Datasets:

nirantk

/

triplets-study-short

like 0

Paralleling of dab converter using the gyrator theory

This work presents mathematical analysis, simulations and experimental results of the parallel connection of DAB converters. The gyrator technique is used to model the DAB converter and to determine a simple equivalent circuit. As the DAB converter is a natural gyrator, the paralleling can be easily done, and the control logic is simplified. A simple current sharing strategy is done by applying the same phase-shift angle between the converters. This technique can be used to connect various DAB converters in a dc microgrid system or to supply power to an isolated load. The main contribution of this study is to show converters that natural gyrator behaves, as in the case of DAB converter may be associated in parallel in a simple manner.

Summary In the pilot study, a new geomodeling technology is presented for developing 3D heterogonous geomodels for Athabasca McMurray (MCMR) oil sands. The geomodels were used to simulate SAGD thermal recovery. Both conventional SAGD completions and SAGD with ICD completions were tested. The simulation results show that for a heterogeneous Athabasca McMurray oil sand reservoir, the ICD completion technology enhances oil production and reduces steam consumption. As a result, the economics of SAGD recovery from the heterogeneous sands is improved.

eng_Latn

Behavior of countercurrent liquid‐liquid columns with a liquid metal

Packed columns are being considered for contacting liquid metals with molten salts to extract fission products from spent nuclear fuel. Extraction rates between a liquid cadmium alloy and a liquid chloride salt were measured at 530°C. in a prototype column. With a system of water and a low melting metal alloy, measurements of the pressure drop, limiting flow rates, and hold-up were made and compared with the predictions of existing correlations. These data indicate that packed columns might be effective contacting devices for pyrochemical processes.

This study investigates the hydrodynamic performance of a submerged two layer horizontal plate breakwater. The plate thickness is considered as non-zero in the study. In the context of linear potential theory, an analytical solution for interaction of water waves with the plates is obtained using the matched eigenfunction expansion method. The solution consists of a symmetric part and an antisymmetric part. Its validity is confirmed by comparing the numerical results of reflection and transmission coefficients for limiting cases with previous predictions. Numerical examples are given to examine the major factors that affect the reflection and transmission coefficients of the plates. Some useful results are presented for engineering design.

eng_Latn

Pseudo—particle simulation of multi—scale heterogeneity in fluidization

Fluidization is a process of wide application, but its dynamic behavior is not well understood because of its multi-scale heterogeneity and regime multiplicity which are difficult to simulate in traditional numerical methods. By discretizing the fluid phase into a large number of interactive simple particles, which can incorporate many-body moving boundaries easily, pseudo-particle modeling (PPM) has reproduced reasonable radial and axial heterogeneity on macro-scale as well as solids clustering and fluid flows on meso- and micro-scales. The simulation suggests a consistent evolution of the complexity across different scales with itself serving as an ideal exploring tool.

In this paper, the authors identify the scalability bottlenecks of an unstructured grid CFD code (PETSc-FUN3D) by studying the impact of several algorithmic and architectural parameters and by examining different programming models. The authors discuss the basic performance characteristics of this PDE code with the help of simple performance models developed in their earlier work, presenting primarily experimental results. In addition to achieving good per-processor performance (which has been addressed in the cited work and without which scalability claims are suspect) they strive to improve the implementation and convergence scalability of PETSc-FUN3D on thousands of processors.

eng_Latn

Mechanism of hydration of simple olefins in aqueous solution. cis- and trans-cyclooctene

Hydratation des cis- et trans-cyclooctenes et du dimethyl-2,3 butene-2 en alcools correspondants dans divers milieux

In order to study the unit's movement law,a transient dynamic response model of large hydroelectric machines is established.The model couples the whole unit such as main shaft,generator rotor,turbine runner and various bearing supporting,and involves consistent quality of the unit shaft,gyroscopic inertia and angular inertia.The finite element method and direct numerical integration method are used in the calculation.Through an engineering example,the numerical simulations of time-course response and axes contrail are respectively carried out when the units are acted under transient initial displacements and transient imbalance loads.The calculated results are discussed and analyzed.By means of comparison between calculated and measured data,their results are close.

eng_Latn

Valve regulated batteries-losses of water and hydrogen through the valves and the battery containers at elevated temperatures

During accelerated testing of valve-regulated (VR) batteries there have been uncertainties about the failure modes and the accelerating factors involved. An experimental study has been performed with the batteries in an enclosed environment where the gases given off by the battery at elevated temperatures have been measured. The diffusive leakage of water and hydrogen as well as the vented gases have been measured. The results are discussed in terms of rate of dry out and corrosion. The influence of different VR-technologies is also discussed. >

On the base of building a HEV propulsion model,the simulation synthesis for a closedloop control system of a given HEV is built.By analysing the virtual velocity output and the desired input torque on the time domain of the HEV at different target velocitys and controller parameters,we has found that it is difficult to achieve both the objects of consumption minimization and dynamic function optimization using the conventional control strategies for HEV.In this paper,a control method for the HEV propulsion system based on the dynamic process is proposed,and its principle and implement are discussed.

eng_Latn

Conformational Polymorphism in Autophagy-Related Protein GATE-16

Autophagy is a fundamental homeostatic process in eukaryotic organisms, fulfilling essential roles in development and adaptation to stress. Among other factors, formation of autophagosomes critically depends on proteins of the Atg8 (autophagy-related protein 8) family, which are reversibly conjugated to membrane lipids. We have applied X-ray crystallography, nuclear magnetic resonance spectroscopy, and molecular dynamics simulations to study the conformational dynamics of Atg8-type proteins, using GATE-16 (Golgi-associated ATPase enhancer of 16 kDa), also known as GABARAPL2, as a model system. This combination of complementary approaches provides new insight into a structural transition centered on the C-terminus, which is crucial for the biological activity of these proteins.

Polymer flooding is an important method of enhanced oil recovery,however,after long-term development of polymer injection,the reservoir physical properties has changed,and as the reason of the heterogeneity of reservoir development,exiting high permeability and large pore so on.The M124 fault block in the process of polymer flooding along the dominant path emerges channeling flow problem,it seriously restricted the development effect.In order to quickly identify the advantages of channeling the flow passage,the mathematic model is established for optimization advantage channeling circulation way by the fuzzy comprehensive evaluation method.By case analysis shows,using fuzzy comprehensive evaluation is an objective and effective method for optimization advantages of channeling the flow passage,which convenient calculation,easy to operate and promotion.

eng_Latn

Experiment of Axial Flow Cyclone Dust Collector in Furnace for Industrial Boiler

Efficient dust emission control of axial flow cyclone dust collector for industrial boiler is proposed by experimental study.From research work on the effective factors of collection efficiency and drag coefficient,which are outlet diameter,inlet blade angle,and length of steady flow etc,it is derived that the proper outlet diameter is 0.7 times the size of the diameter of separator,the appropriate inlet blade angle is 60 ° for drag coefficient trends great while inlet blade angle goes small,and the length of steady flow rests with weighing the effect of collection efficiency and drag coneffcient.Therefore,the configuration of axial flow cyclone dust collector suitable for industrial boiler application is achieved,which applies experimental and research information to the improvement of industrial boiler.

The flow through a double throat nozzle is computed using the complete time-dependent compressible Navier-Stokes equations. The computations were performed by using an existing working code, which uses MacCormack’s explicit finite difference scheme. There were no special modifications made in the code for this particular application. The computations were performed on a Cyber 84 5 computer and a CRAY XMP-48 computer using three different grid sizes.

eng_Latn

Coupled study of the film and spray on a basic annular prefilming airblast atomizer

One way to increase efficiency and reduce pollution in transport and energetic domain is designing fuel injectors with better atomization. In this work, experiments were performed on a prefilming airblast atomizer often used in gas turbine engines. For this purpose, a new injector was designed to visualize the prefilming zone and the primary atomization together. The flow configuration corresponds to an annular liquid film sheared by inner high velocity airflows. High speed Shadowgraphy was used to observe film and spray, liquid film frequency, wave velocity and wave deformation, primary breakup regime. Finally, a link between liquid film and the primary atomization are shown first qualitatively and after quantitatively.

Electropneumatic actuators are more and more used in industrial applications. Due to nonlinear phenomena, for many applications, high accuracy can only be obtained when using nonlinear control laws. These strategies allow to get high performances but often need the knowledge of all state variables. Then, there is a real interest to design observers in order to estimate state from the measurements of only one of the chamber pressures in the actuator and carriage position. This paper focuses on a comparison between two nonlinear observers for a half-meter stroke electropneumatic unsymmetrical cylinder controlled by two three-way servodistributors: a high gain observer and a sliding mode one. Simulations are made with a fluid power systems dedicated software, AMESim.

eng_Latn

A numerical study on the effect of vibrator shape on the development of nonlinear standing waves in a 2-D acoustical resonator

The numerical analysis of the effects of different shape of the vibrator on the pressure and velocity profile in 2-D nonlinear standing wave resonator is studied. The wave equation for high-amplitude nonlinear acoustic waves in a thermo-viscous fluid is derived from the basic equations of fluid mechanics along with an appropriate state equation. Three different shapes are considered for the diaphragm which are, constant shape vibrating piston, circular shape and cosine shape, to investigate the effects of the diaphragm shape on the pressure and velocity waveforms of an acoustic resonator. It is observed that for the same maximum vibrational velocity of the diaphragm, the amplitudes of the pressure and velocity for constant shape vibrating piston are largest and for cosine shape are smallest.

Abstract By applying wrapping (Dattatreya Rao et al (2007)), offsetting (Girija et al (2013 and Radhika et al (2013)) and stereographic projection (Phani et al (2012)) have constructed circular models. Further the circular models based on the Rising Sun function are motivated by purely mathematical considerations as a smoothing function and possible application. This work takes a further step in this direction using several mathematical tools such as Real Analysis along with MATLAB and are applied to enlarge the horizon of Mathematical Statistics. Here an attempt is made to construct new circular models using the Rising Sun function and also the circular rising sun lemma is proposed

eng_Latn

Multi-objective optimization for characterization of optical flow methods

Optical flow methods are among the most accurate techniques for estimating displacement and velocity fields in a number of applications that range from neuroscience to robotics. The performance of any optical flow method will naturally depend on the configuration of its parameters. Beyond the standard practice of manual (ad-hoc) selection of parameters for a specific application, in this article we propose a framework for automatic parameter setting that allows searching for an approximated Pareto-optimal set of configurations in the whole parameter space. This final Pareto front characterizes each specific method, enabling proper method comparison. We define two performance criteria, namely the accuracy and speed of the optical flow methods.

A new oxygen-enrich combustion chamber of micro gas turbine running with flue gas circulating was preliminary designed.The basic geometric dimension of the combustion chamber, the location of the secondary air and mixing cooling hole,and the swirl burner's structure were designed to meet the requirements of high combustion efficiency and stability,total pressure recovery coefficient,outlet temperature field regulation and other aspects.Besides,the CFD software was used to study the performance of designed combustion chamber,like hot flow field,combustion stability,combustion efficiency,pressure loss and so on.The results show that,the combustion chamber has reasonable flow field,stable combustion,high combustion efficiency and small pressure loss,which basically satisfies the design requirements.

eng_Latn

Nusselt number influenced by expansion/compression, birth/death, and recirculating direction of vortices in elongated enclosures

Abstract Buoyancy-driven recirculating flows between two parallel plates, whose temperature varies sinusoidally, have been attentively investigated. In this study, we place our emphasis on joint effects rendered by both (a) the existence of two insulated side walls and (b) the phase of the bottom-surface sinusoidal temperature on the overall Nusselt number (Nu) of the system. Using the finite-element-based COMSOL and the finite-volume-based ANSYS Fluent packages, we have discovered that Nu is gradually affected by expansion and compression of vortices, as well as is abruptly affected by birth and death of vortices. Under the width-divided-by-height aspect ratio of ten, these gradual or abrupt variations for airflows remain conspicuous regardless of the wave number and the Rayleigh number.

In this paper, we consider the density-dependent incompressible Navier–Stokes equations in with linearly growing initial velocity at infinity. We obtain a blow-up criterion and global well-posedness of the two-dimensional system. It generalized the local well-posedness results due to the recent work by the first and third authors to the global well-posedness in . Copyright © 2012 John Wiley & Sons, Ltd.

eng_Latn

Air-Mattress Motion Therapy for Respiratory Failure After Cardiothoracic Surgery

Purpose ::: The standard management of respiratory failure after cardiothoracic surgery involves prolonged mechanical ventilation, drug support, and chest physiotherapy. We report the effectiveness of a novel type of respiratory physiotherapy, the air mattress V-CUE unit, which utilizes a computerized automatic combination of three movements: rotation, percussion, and vibration.

Exergy analysis permits meaningful efficiencies to be evaluated for a system or process, and the sources, causes and locations of thermodynamic losses to be determined. This study presents exergetic modeling of a small turbojet engine via exergetic response surfaces. Turbojet engine consists of an inlet, a centrifugal compressor, reverse flow combustion chamber, axial-flow turbine and exhaust nozzle. The flight Mach number and altitude are examined on the exergetic efficiencies of total engine performance. The results of analysis are given as three dimensional exergetic response surface plots related to these operating parameters.

eng_Latn

Numerical study on oxygen-enriched combustion chamber of micro gas turbines

A new oxygen-enrich combustion chamber of micro gas turbine running with flue gas circulating was preliminary designed.The basic geometric dimension of the combustion chamber, the location of the secondary air and mixing cooling hole,and the swirl burner's structure were designed to meet the requirements of high combustion efficiency and stability,total pressure recovery coefficient,outlet temperature field regulation and other aspects.Besides,the CFD software was used to study the performance of designed combustion chamber,like hot flow field,combustion stability,combustion efficiency,pressure loss and so on.The results show that,the combustion chamber has reasonable flow field,stable combustion,high combustion efficiency and small pressure loss,which basically satisfies the design requirements.

Adopt optimum compound design to study the regression relation of hybrid maize yield, relating to density ,quantity applied of feirtilizer-N、 fertilizer-P_2O_5、 fertilizer-K_2O Regression model was set and the optimum cultivation technique was obtained by the aid of computer statistics.

eng_Latn

Liquid-gas phase transition and its order in finite

The liquid-gas phase transition in finite nuclei is studied in a heated liquid-drop model where the drop is assumed to be in thermodynamic equilibrium with the vapour emanated from it. Changing pressure along the liquid-gas coexistence line of the systems, symmetric or asymmetric, suggests that the phase transition is a continuous one. This is further corroborated from the study of the thermal evolution of the entropy at constant pressure.

This paper presents a novel p tubular linear generator (PMTLG) buoy sy convert the linear motion of the ocean wav energy. The design incorporates no working water airgap bearing surface integration betw components. The internal generator design w addition to the system integration with the bu the linear test bed performance results.

eng_Latn

Dissipative control system for the stochastic nonlinear H∞ problems

Abstract We characterize functions satisfying a dissipative inequality associated with a stochastic control problem. Such a characterization is provided in terms of an upper generalized Gaussian solution, or a viscosity supersolution to a partial differential equation called Hamilton–Jacobi equation (H–J). Links between upper generalized Gaussian solutions and viscosity supersolutions to Hamilton–Jacobi equation are studied. Finally it shows that generalized Gaussian solutions is identical to viscosity solutions to Hamilton–Jacobi equation.

Abstract The present investigation deals with a theoretical analysis of direct contact sensible heat transfer between two immiscible liquids in a countercurrent spray column. The non-dimensional parameters governing the heat transfer process are identified and a study of the effects of the variation of these parameters is made. The predicted column heights and the temperature profiles of both the phases along the column compare favourably with the available experimental data.

eng_Latn

Research on Self-adaptive Fuzzy Control for Keeping Engine Speed Constant During Vehicle Starting

Keeping engine speed constant during vehicle starting is an effective control method, but how to make engine speed vary with the target speed curve so as to improve starting quality is a difficult issue. To solve the problem, a new clutch control principle was proposed, and a control system comprised of a self-adaptive fuzzy controller constructed by engine speed and its target speed and clutch displacement and rule harmonizing controller was devised. The simulation experiment show that engine can reach its target speed with little overshot under diversiform situation and vehicle starts successfully with constant engine speed and small friction loss as well. The start quality is proved to be improved through applying the strategy.

AbstractThe numerical analysis of two-dimensional laminar vortex shedding from a rectangular cylinder within a confined channel flow is presented. This study, carried out using a computational fluid dynamics (CFD) code based on the SIMPLEST algorithm, considers the influence of numerical diffusion on the prediction of the vortex shedding frequency. The computational analysis compares the commonly used first-order accurate UPWIND scheme with the well-known third-order scheme QUICK and its derivative SMART, used for the discretization of convective transport. For the temporal differencing, a fully implicit scheme has been adopted. Plots of Strouhal number against Reynolds number suggest that the implementation of a higher-order scheme is beneficial for the accurate capture of the vortex shedding transient in unsteady flows of this nature.

eng_Latn

Visual study of capabilities of managing IC engine filling degree vs engine ecological indicators

The operation of an internal combustion engine in a transient state is related to constant changes in cylinder filling degree. Managing a steady course of engine torque demands constant corrections in the volume of air delivered to the engine. In this work, different engine throttle management strategies were analyzed. The effect of throttle velocity on emissions was depicted. The research has shown that the greatest value of work density is reached by the IC engine for relatively low values of throttle angle. For shown values, disturbances in air flow in engine intake which may adversely affect emissions due to uneven cylinder filling were researched with the use of Digital Particle Image Velocimetry. The conducted research has shown significant unevennes in air supply to individual cylinders in the engine. This effect may cause discrepancies in air excess ratio for each cylinder, and result in heightened harmful substance emission.

A suit of integrity emission factor for burning fuel is important when we calculate the emission of air pollutants by counting the fuel consumption In this article, we have taken five difference ways to have obtained a suit of emission factor for various burning fuels and many kinds of burning modes through deep research in Guangzhou

eng_Latn

A Study on the Propeller Blade Singing Place of an 86,000 Ton Deadweight Crude Oil Tanker

A study was conducted to investigate the propeller singing place of an 86, 000 ton Deadweight Crude Oil Tanker. In preliminary study, proper use of finite element analysis was verified by comparing with the result of hammering test in the air. Then the finite element analysis was carried out for the blade in the water and compared with the noise measurement during sea trial, which enabled to confirm the local resonances of blade structure. Result of the study showed that the singing occurred most probably at trailing edges on the blade tip over 95% of propeller diameter. Owing to edge cutting of a successfoul remdial action, the singing excitation forces seemed to be reduced whereas the vibration characteristics of the blade was not changed.

This paper presents a novel p tubular linear generator (PMTLG) buoy sy convert the linear motion of the ocean wav energy. The design incorporates no working water airgap bearing surface integration betw components. The internal generator design w addition to the system integration with the bu the linear test bed performance results.

eng_Latn

Design study of certain high efficiency micro-centrifugal pump

According to the requirements of the manufacturer about the performance of the computer water-cooling centrifugal pump,the structural shape of water pump was determined by the elementary theory of vane type oil pump and blower fan,based on the basic design parameters which were selected reasonably,the calculated mode of the impeller vane and the volute contour of the water pump were obtained by introducing the methods of implicit function derivation and coordinate transformation,the physical design of this kind of water pump was completed.Experiment indicated that the actual performance of the recycle pump satisfied the end requirements with the advantage of small size,rational distribution and low cost.

ABSTRACTThis paper aims to develop, assess, and numerically implement analytical models for the newly introduced Quintuple Friction Pendulum Isolator (QFPI) which can identically capture its real e...

eng_Latn

Icing Limit and Wet-Surface Temperature Variation for Two Airfoil Shapes Under Simulated High-Speed Flight Conditions

Report presenting a study of the wet-surface temperature and stream conditions that result in ice-free surfaces for bodies in flight through icing clouds and a comparison of these experimental results with calculated results using the analytical method. Two symmetrical airfoil models were used in the investigation and testing occurred for a range of Mach numbers and pressure altitudes. Results regarding chordwise variation of pressure distribution, chordwise variation of recovery factor, results with the diamond airfoil and circular-arc airfoil, and the experimental and analytical results are presented.

A model for forecasting enroute controller requirements was developed by Tien and Schonfeld [1] for incorporation into the FAA's NAS Strategy Simulator. In this study, one critical component in their work is improved by using probit regression model in order to more reasonably predict the number of controller positions per sector. Probabilities of using between 0 and 4 controllers per sector are estimated from the controller work history based on traffic densities and other sector characteristics. The improved controller estimation model is then demonstrated for its practicability and can provide an estimate of annual controller requirements in response to future traffic growth and capacity for evaluating future enroute performance.

eng_Latn

Flow of a Polar Fluid between Two Eccentric Rotating Cylinders

The flow of a creeping polar fluid between two eccentric rotating cylinders is analyzed. A perturbation series is applied to solve the system of partial differential equations. The dependence of the velocity components and the spin on the coupling number N and the length ratio L is discussed.

In the oil production and thermal recovery in the application of oil and gas field, well of curves are regarded as the crooked canal(namely not only the canal has horizontal section but also vertical section), it instead the horizontal well before. Thus establishmented the new elbow well model, the solution of the model not only suitable for theoretical study but also easy to calculate in practical production. This article considered the problem of indeterminate percolation of spherical symmetry infinite domain described by the initial boundary value problem of the system of partial differential equation and obtained the point-source accurate solution when research on the problem of indeterminate percolation for double porosity medium. Abtained the accurate solution about mathematical model of line source from appling the point-source accurate solution, and applied the results to mathematical model of well of curves, obtained the integral expression of it’s accurate solution.

eng_Latn

Regulation and Optimal Error Reduction in Linear Multivariable Systems

Abstract In this paper, we study a general problem of optimal error reduction in linear multivariable systems. We show how a symptotic regulation can be achieved along with minimization of the H∞ norm of the error transfer function matrix. These resulte are of significance in the development of a new approach to the design of multivariable control systems.

Simulating a radial-inflow turboexpander from its nozzle inlet to the impeller output as the single nozzle, and through theoretic analysis, this thesis concludes two general characteristic models for design and off-design steady-state of the turboexpanders. Based on experiment data, and generalized least squares method is used in imitation of the data, the coefficient solutions which are needed to describe the models have been obtained. Using the model to predict performance of the other two turboexpanders, the results show that the two general characteristic models in this thesis are more accurate and universal. Therefore, in design of turboexpanders, as two important models, they can give a base for optimizing design and off-design characteristic.

eng_Latn

Gas Dynamics in a Counterflow Cyclone with Conical Nozzles on the Exhaust Pipe

Countercurrent cyclones have been quite widely applied in various industries [1-12]. In this paper, on the example of classical construction of countercurrent cyclone considers the impact of the conical nozzle on the exhaust pipe to the gas-dynamic picture and efficiency dedusting.

Synchrotron X-ray diffraction study for solid CO2 at 40?100 GPa and around 2,000 K has shown that the diffraction pattern of the high pressure phase CO2-V is consistently interpreted in terms of a tetragonal uni_t cell (Z = 4, a = 3.584 ?, c = 5.908 ? at 50GPa). A ?-cristobalite structure (space group I2d) gives a good account of our data qualitatively. Isothermal molar volume (300K) of the CO2-V in the present study is smaller than that indexed as a tridymite structure proposed by previous studies at any pressures.

eng_Latn

Horizontal well top end steam injection device

The utility model provides a horizontal well top end steam injection device, and relates to a device used for oilfield production. The horizontal well top end steam injection device is provided with an outer tube provided with a steam outlet, a cone-shaped guide head is arranged at the front end of the outer tube, an inner tube is arranged inside the outer tube, a joint is arranged at the outer end of the inner tube, and a support plate is arranged between the outer tube and the inner tube. The horizontal well top end steam injection device can send steam to a far-well zone, and effectively reduces thickened oil viscosity; and good heating can be obtained by a near-well zone and the far-well zone, and exploitation of thickened oil is benefited.

This numerical study pertains to characterizing flow and heat transfer interactions for an interrupted fin design with wavy profile in a compact tube-and-fin heat exchanger. Sinusoidal wavy fin is ...

eng_Latn

Pattern formation in self-propelled particles with density-dependent motility

We study the behavior of interacting self-propelled particles, whose self-propulsion speed decreases with their local density. By combining direct simulations of the microscopic model with an analysis of the hydrodynamic equations obtained by explicitly coarse graining the model, we show that interactions lead generically to the formation of a host of patterns, including moving clumps, active lanes, and asters. This general mechanism could explain many of the patterns seen in recent experiments and simulations.

We present a novel numerical method based on finite differences to solve the problem of impurities' migration from a hollow core multilayer cylinder filled with a known liquid medium. We expose the numerical method and the developed application. The validation is performed by calculating the migration in a configuration which allows an analytic solution. Applications are foreseen in modeling impurities' migration from modern multilayer water pipes into drinking water.

eng_Latn

The design of transonic aerofoils by a well‐posed inverse method

This paper describes a numerical method for designing closed aerofoils that correspond to given surface speed distributions including flows with shock waves. The prescribed surface speed distribution in general contains three parameters whose values are found as part of the solution. The inverse aerofoil design problem is not well posed unless the prescribed speed satisfies three constraints that can be used to fix the value of the three adjustable parameters. The computational method is based on the numerical solution of the full potential equation in conservation form by an approximate factorization–multigrid scheme. The nature of the constraints and several strategies for introducing the necessary freedom in the prescribed speed are discussed along with typical solutions illustrating the method.

Some results of studying thermodynamics of the tropical tropopause and lower stratosphere performed with the help of the stratospheric M-55 Geofizika research aircraft during the international TROCCINOX experiment in 2005 in Brazil are considered. New data on a mesoscale structure of the wind, temperature, and humidity fields over the continental tropics are derived.

eng_Latn

An Integrated Humidification System for a Fuel Cell Vehicle

In this study, we suggested an integrated humidification system for a fuel cell electric vehicle (FCEV) as an efficient method of humidification under the various driving condition of the fuel cell vehicle and system. It is improving air humidification system combined the existing membrane humidifier and water injection. As a result, we verified it through experiments and the vehicle test and could get a result of improvement of humidification performance. The results show that an integrated humidification system is a useful method for FCEV applications.

An excessive level of moisture in building damages their quality. Key factors associated to the development of this damages mainly depend on the hygrothermal fields inside building envelope. These key factors can be associated with HAM models to predict the development of moisture damages. Different granularities of HAM modelling exist in literature and can be used. In this paper, main advantages and drawback of most common approaches are presented and discussed. A test case is chosen to illustrate the different issues.

eng_Latn

Compressibility Effects in Unsteady Thin-Airfoil Theory

This is the same equation as obtained by Goodman, for the melting rate, using the heat balance integral method Results for surface temperature-time history <D(i) and the melting rate f/(i) for different values of /? are plotted in Figs. 1 and 2, respectively, and compared with Goodman's solution. It is concluded that Biot's variational method is applicable to the phase-change problem with aerodynamic heating. The simplicity of the method lies in using only a linear temperature profile, yielding satisfactory results.

Some results of studying thermodynamics of the tropical tropopause and lower stratosphere performed with the help of the stratospheric M-55 Geofizika research aircraft during the international TROCCINOX experiment in 2005 in Brazil are considered. New data on a mesoscale structure of the wind, temperature, and humidity fields over the continental tropics are derived.

eng_Latn

A stochastic turbulence theory-based numerical model of 3-D flow in a dredged channel

A 3D numerical model is established based on the stochastic turbulence theory developed by Dou Guoren, which can simulate flow in dredged channels in coastal and estuarine areas. The governing equations are discretized using a controlvolume method and the pressure term is divided into dynamic and static terms. The solution procedure is based on the wellknown SIMPLE method, and the free surface level is obtained by solving the watersurface equation. The turbulence closure model used in this study is nonisotropic in terms of eddy viscosity and turbulence stress calculations, which is different from the k-e model and can include the k-e model as a special case. The numerical model is applied to several dredged channels and the predicted flow agrees well with experimental measurements.

This paper is concerned with the Free boundary problem for the one-dimensional compressible Navier-Stokes equations with density-dependent viscosity. A local (in time) existence result is established when the initial density is of compact support and connects to the vacuum continuously. (C) 2002 Elsevier Science (USA).

eng_Latn

The Origin of Aerodynamic Instability of Supersonic Inlets at Subcritical Conditions

Memorandum presenting an investigation of the phenomenon of the starting of aerodynamic instability or buzz in supersonic inlets with external compression. The starting of the buzz has been related to the existence in the flow field of a velocity discontinuity across a vortex sheet which originates at a shock intersection. Results regarding the inlets without separation on the central body, inlets with separation on the central body, the regulation of entering volume flow at angles of attack, experimental performance of various inlets, and an application of the results are provided.

Abstract : This thesis presents a study of radiation patterns for low-gain antennas installed on aircraft. With the aid of the computer program APATCH, a simulation of the radian on patterns for a given antenna located at various points on an aircraft structure can he evaluated. The program uses a technique referred. to as Shooting and Bouncing Rays (SBR), which is valid for structures that have typical dimensions of ten wavelengths or more. A Cessna 172 aircraft with a quarter-wavelength monopole antenna and an F-18 aircraft with a telemetry antenna are analyzed.

eng_Latn

Flow Investigation on Different Combustion Chamber Configuration in a DI Diesel Engine – A CFD Approach

The main objective of the present investigation is to make a computational study of flow structure inside the engine cylinder in a DI diesel engine during the end of compression stroke at an engine speed of 1000 rev/min. The analysis has been carried out for four different piston configurations viz., flat piston, centre bowl on flat piston, inclined and inclined offset bowl piston. A polyhedral trimmed cell has been adopted for meshing the geometries using the code called STAR-CD Es-ice. The flow has been simulated by solving the governing equations of conservation of mass, momentum and energy using the SIMPLE algorithm. From this numerical prediction, the best possible combustion chamber configuration and the location of fuel injector on the cylinder head have been arrived.

In this paper,the key point of drawing die process?of wide flange drawing workpiece is exhaustively discussed,the plan of designing an optimized drawing die process is given and the development of the drawing die CAD system is discussed.After inputting the interrelated parameter,the designing and 3D drawing of drawing dies could be given by the CAD system,which could improve observably the quality and efficiency of the die design.

eng_Latn

Numerical Analysis of Fluid Flow and Heat Transfer in Wavy and Hybrid-Slit-Wavy (HSW) Fin-and-Tube Heat Exchangers

This numerical study pertains to characterizing flow and heat transfer interactions for an interrupted fin design with wavy profile in a compact tube-and-fin heat exchanger. Sinusoidal wavy fin is ...

For better control of the hydro turbine generating units,it is desirable to identify the model of the subject of the hydro turbine governing system before optimizing its control parameters.The nonlinear model of the hydro turbine governing system is established first.Its parameters are identified with the Recursive Least Square method(RLS).The simulation experiments demonstrate that the difference between the identified model and the real one is rather small.The method is simple,effective and easy to implement.The optimization of the control parameters can be further made based on the identified model to improve the dynamic performance.Therefore it is valuable and practical.

eng_Latn

The lift on an aerofoil in starting flow

An analysis is given of the initial development of the lift on an aerofoil in inviscid starting flow. It is shown that because of the spiral shape of the vortex sheet shed initially from the trailing edge the lift and drag are both singular at the start of impulsive motion. This result is in contrast with the prediction of finite forces by methods that assume the vortex sheet to be initially planar. The effect of a steady rate of change of incidence following the sudden onset of transverse (heaving) motion of an aerofoil in a steady stream is also discussed.

In this paper, we study the asymptotical optimal solutions for the general airline revenue management problem, considering both customer cancelations and no-shows. We study a simple case where there is only one fare-class; the management controls the opening and closing of the fare-class, with the objective of maximizing the total revenue. We first develop a fluid control problem, where the customer arrival and cancelation processes are treated as deterministic, whereas the no. of no-shows is random. The optimal fluid solution is shown to have a simple structure of accepting up to a single time point t* and rejecting afterwards. We show that this policy acts as an upper bound for the MDP problem. Applying the optimal fluid solution to the stochastic environment, we show that this policy is asymptotically optimal on the fluid scaling.

eng_Latn

Numerical study of unsteady turbulent cavitating flows

Abstract The simulation of cavitating flows is a challenging problem both in terms of modelling the physics and developing robust numerical methodologies. Such flows are characterized by important variations of the local Mach number, compressibility effects on turbulence and involve thermodynamic phase transition. To simulate these flows by applying homogeneous models and Reynolds averaged codes, the turbulence modelling plays a major role in the capture of unsteady behaviours. This paper presents a one-fluid compressible Reynolds-Averaged Navier–Stokes (RANS) solver with a simple equation of state (EOS) for the mixture. A special focus is devoted to the turbulence model influence. Unsteady numerical results are given for Venturi geometries and comparisons are made with experimental data.

Populations oscillations in isolated populations of flies are considered. Qualitative methods of analysis are applied to the functional differential equation representing the system and conditions for the occurrence of oscillations are derived. These conditions are readily visualized in terms of parameters which are easily measured and have a straightforward biological interpretation.

eng_Latn

Turbulent Heat Transfer in the Entrance Region of a Tube

Correlation of the data for heat transfer between a fluid in turbulent flow and the entrance region of a tube is made for the entrance shapes normally used in heat exchangers. Equations representing the variation of the “average heat transfer” with tube length, Reynolds number, and Prandtl number are suggested.

Exergy analysis permits meaningful efficiencies to be evaluated for a system or process, and the sources, causes and locations of thermodynamic losses to be determined. This study presents exergetic modeling of a small turbojet engine via exergetic response surfaces. Turbojet engine consists of an inlet, a centrifugal compressor, reverse flow combustion chamber, axial-flow turbine and exhaust nozzle. The flight Mach number and altitude are examined on the exergetic efficiencies of total engine performance. The results of analysis are given as three dimensional exergetic response surface plots related to these operating parameters.

eng_Latn

Experimental study on three dimensional movements of particles II Effects of particle diameter on turbulence characteristics

Abstract Based on the 3D PTV (Particle Tracking Velocimetry) measuring system, the 3D movement characteristics of particles with four different diameters were investigated. Under specific flow conditions, the impact of particle diameters on 3D motion of particles was studied, and the turbulence characteristics were analyzed by different statistical methods. The results showed that the turbulence intensity of coarse particle decreased as the diameter increased. In near wall region, the probability density distributions of longitudinal and vertical fluctuation velocities both deviated from the normal distribution; while in the outer region, the probability density distribution of vertical fluctuation velocity approximately agreed with the normal distribution.

Summary First a short analysis and description is given about the profile geometry of special twist drill. Different groups of profiles are defined. The influence of the cross section profile to the torsional stiffness was determined and related to the drilling process. Torque and thrust were measured under variation of speed, feed, depth and point geometry. Testing the different dynamic behaviour of the twist drills is included.

eng_Latn

Teaching Rayleigh–Plateau instabilities in the laboratory

The breakup of a liquid jet into spherical droplets via the Rayleigh–Plateau instability is a common and fundamental part of fluid mechanics. However, teaching this instability in a laboratory setting is challenging, requiring sophisticated methods to generate and study the jet dynamics. Recently, toroidal droplets were shown to break into one or more spherical droplets in the thin-drop limit via the Rayleigh–Plateau instability. We propose a simple experimental setup to generate toroidal droplets that break up on the order of tens of seconds, allowing for easy video capture using a basic CCD camera. With this setup, it is possible to quantify the Rayleigh–Plateau instability in a pedagogical laboratory setting. In addition, the role of curvature on jet breakup can be explored using thick toroidal droplets. We envision this setup as a powerful teaching tool for one of the most fundamental fluid dynamics processes.

In this paper,the stability of a class of stage structure SIS model with small delay is studied.The sufficient conditions for asymptotical stability of the equilibrium are given.Some simulations are carried out by matlab software to support the correctness of our analysis results.Owing to the small delay,the results are the continuation and complement of the previous authors.

eng_Latn

Morawetz 's research was mainly in the study of the partial differential equations governing fluid flow , particularly those of mixed type occurring in transonic flow .

Morawetz 's research was mainly in the study of the partial differential equations governing fluid flow .

Most ballistic mathematical models and hence tables or software assume that one specific drag function correctly describes the drag and hence the flight characteristics of a bullet related to its ballistics coefficient .

eng_Latn

what does aerodynamic mean in an adjective

noun, (used with a singular verb) 1. the branch of mechanics that deals with the motion of air and other gases and with the effects of such motion on bodies in the medium. Compare aerostatics (def 1). Origin of aerodynamics.

Sometimes, the speed of an object is described relative to the speed of something else; preferably some physical phenomena. 1 Aerodynamics is the study of moving air and how objects interact with it. 2 In this field, the speed of an object is often measured relative to the speed of sound.

eng_Latn

“Glassy” low-temperature thermal properties in crystalline superconducting ZrNb alloys☆

The Anisotropic Glassy Properties of Decagonal Quasicrystals

An NQR study of the crystalline structure of TNT

eng_Latn

Numerical study of the stress condition in the coatings surface layers obtained by electro-spark alloying of hard alloys

Modeling of the Temperature Field on the Cathode's Surface during Electrophysical Impact

Inability of the Submaximal Treadmill Stress Test to Predict the Location of Coronary Disease

eng_Latn

Formation and evolution of MnNi clusters in neutron irradiated dilute Fe alloys modelled by a first principle-based AKMC method

Stability and mobility of small vacancy–solute complexes in Fe–MnNi and dilute Fe–X alloys: A kinetic Monte Carlo study

Mdm2 promotes the rapid degradation of p53

eng_Latn

A detailed correlation of the tribological performance of arc-evaporated TiC 1− x N x coatings with testing temperature, atmosphere as well as variation in load and sliding velocity is presented in this paper. The low-friction behavior in combination with its mechanical integrity are the reasons for the extensive industrial application of TiC 1− x N x over the last decades. Still the tribo-mechanisms behind this performance are not yet completely understood. The present study adds further understanding, as the low-friction behavior degrades at elevated temperatures and dry or inert environments, which is related to the different constitution of the tribo-layer formed as investigated by Raman spectroscopy. Surprisingly, the wear rate of the coatings does not correlate with the coefficient of friction indicating the presence of different wear regimes.

An extensive survey of the papers pertaining to the thermodynamic approach to tribosystems, particularly using the concept of entropy as a natural time base, is presented with a summary of the important contributions of leading researchers.

Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights.

eng_Latn

Biomaterials have been out of commonly used materials in biomedical applications in recent years. Today among the mostly-used biocompatible metals are especially Ni-Ti alloys. For conducting this study, having extensive usage area in biomedical applications, Ni and Ti materials were utilized for an alloy production. Following being mixed using a suitable mixer at 49Ni/51Ti %wt., the alloy was exposed to cold pressure of 200 MPa and sintered in a mold. In addition, the material gained porosity appearance thanks to usage of the synthesized (SHS) method and then the final shape of the specimen was taken using the method of wire electro erosion discharge machining (WEDM). Afterwards, the specimen was subjected to the biocompatibility test in in-vivo environment by means of on a 3-year-old female dog.

Metallic biomaterials are mainly used for replacing failed hard tissue. The main metallic biomaterials are stainless steels, Co-based alloys, and titanium and its alloys. Recently, titanium alloys are getting much attention for biomaterials. The various kinds of new high strength α+β and low-modulus β-type titanium alloys composed of nontoxic elements, such as Nb, Ta, Zr, etc., are developed for biomedical applications because of the toxicity of alloying elements and lack of mechanical biocompatibility of conventional titanium alloys, such as Ti-6Al-4V. Recent research and development in other metallic alloys, such as stainless steels and Co-based alloys, also will be discussed.

Metallic biomaterials are mainly used for replacing failed hard tissue. The main metallic biomaterials are stainless steels, Co-based alloys, and titanium and its alloys. Recently, titanium alloys are getting much attention for biomaterials. The various kinds of new high strength α+β and low-modulus β-type titanium alloys composed of nontoxic elements, such as Nb, Ta, Zr, etc., are developed for biomedical applications because of the toxicity of alloying elements and lack of mechanical biocompatibility of conventional titanium alloys, such as Ti-6Al-4V. Recent research and development in other metallic alloys, such as stainless steels and Co-based alloys, also will be discussed.

eng_Latn

This paper presents calculations of screw dislocation cross slip in copper and nickel systems, using the nudged elastic band method and interatomic potentials based on the effective-medium theory. The validity of recent attempts to predict cross slip activation energies by ‘elastic scaling’ between fcc metals is investigated, finding that reasonable predictions can be made using the approach suggested by Rasmussen [T. Rasmussen, Phil. Mag. A 80 (2000) 1291]. The experimentally determined cross slip activation energy and the minimum stable screw dislocation dipole height for copper are explained on the basis of cross slip of jogged screw dislocations.

In this study, a dislocation-based model is presented for investigating the evolution of microstructure and mechanical properties of thin lms during a wide range of straining. The model is applied to the High Pressure Torsion (HPT) process of thin nickel disks that provides valuable information on the evolution of material parameters during deformation. The model considers a free surface theory for thin lms and can explain the size e ect phenomenon in agreement with previous reported trends in literature.

We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero.

eng_Latn

Analysis of steam oxidation of crystalline SI1-XGEX using AFM and CABOOM

Characterization of the Ge concentration in a Si1-xGe x heterojunction for x varying from 5% to 40% in steps of 5% is done by beveling and wet thermal oxidation of the exposed layers. The resulting difference in oxide thickness as a function of Ge concentration is visualized due to light interference. Different Ge concentrations are seen as different colors through an optical microscope. CABOOM - Characterization of the Alloy concentration by Beveling, Oxidation and Optical Microscopy - in combination with AFM - Atomic Force Microscopy, is used as a tool to study the oxidation kinetics of unstrained, crystalline Si1-xGex by wet thermal oxidation.

Leveraging grid computing technology, i.e. the visualization of distributed computing and data resources such as processing, network bandwidth and storage capacity to create a single system image, we present a Grid Air Quality Forecast System (G-AQFS). The modeling system consists of meteorological and dispersion models coupled in cascade. The computational workflow of the modeling system is defined by means of DAGs (direct acyclic graph). A simple system is presented to manage and schedule the computational grid resources. As case study the system has been applied over Salento area, in the Apulia region (South-eastern Italy), to simulate ground level ozone concentration. Model predictions have been compared with field measurements, with reasonable results.

eng_Latn

The effect of dispersion hardening on the regularities and mechanisms of the creep of copper with submicron grain sizes

Regularities and mechanisms of the creep of submicrocrystalline copper and Cu-1.1 vol % Al2O3 dispersion-hardened powder composite in a temperature range of (0.2–0.35) T m Cu have been investigated. The role that the grain-boundary state and dispersion-hardening material with Al2O3 nanosized (10–40 nm) particles plays in the development of plastic deformation during creep is analyzed.

Abstract A study has been made of surface diffusion in the evaporated thin film couple Ni-Au. Structural changes within the diffusion zone were examined by electron microscopy in situ . Apart from a slight migration of the layers, crystallization was quite pronounced. The results obtained by means of an electron microprobe analyser showed that the diffusion rate was higher than in the bulk.

eng_Latn

An experimental study on the initiation and growth of frost formation on a horizontal plate

An experimental study was made to clarify the fundamental nature of the early stage of crystal growth period of frost formation phenomena. The effect of four dominant parameters on frost formation, namely, plate temperature, air temperature, air humidity ratio, and Reynolds number, are demonstrated through several frost formation properties such as frost height, frost deposition rate, and frost density. The thickness of the frost layer is affected primarily by the air humidity ratio, plate temperature, and air temperature, while the effect of Reynolds number is less significant. High humidity ratio, Reynolds number, and temperature difference between the air stream and the plate all yield high mass deposition rates. Frost density depends primarily on frost surface temperature, besides the other parameters. Vapor diffusion in the frost layer during the crystal growth period was found to be insignificant,

Abstract In this letter, we report clear correlations between the glass transition temperature Tg, the crystallization temperature Tx, the Curie temperature TC and the electronegativity based on statistically analyzing more than 200 kinds of soft magnetic Fe-based amorphous alloys. The underlying physical origin of these correlations is discussed. Based on these correlations, the influences of various alloying elements are classified. These results are helpful for designing new soft magnetic amorphous alloys with high thermal stability.

eng_Latn

Acoustic-Emission Testing of Failure in Samples of CFRP Exposed to Static and Heat Loads

The results of testing samples made of T700 carbon fiber reinforced plastic with a stress concentrator in the form of a hole 14 mm in diameter are considered. Some of the samples were heated to a temperature of +100°C, followed by exposure to a static tensile load, with the remaining samples statically loaded at a temperature of +20°C. In the process of loading, information was recorded using the method of acoustic emission. At first, the samples were loaded statically up to 50 kN, which was 50% of the average breaking load. Then the load was increased in increments ΔP = 10 kN until sample failure. It was observed that the simultaneous exposure of samples to static and heat loads decreased the load capacity of the samples.

We present a computer simulation study of thin crystalline multilayers constructed from two FCC solids with differing lattice constants and binding energies. Both materials are described by Lennard-Jones interatomic potentials and initially have the same orientation and coherent interfaces. We have studied systems in which interfaces are perpendicular to the common [100] and [111] directions, respectively. A novel technique for analyzing local atomic ordering, Common Neighbor Analysis, is used to identify structural characteristics in these systems. We have found several structural changes in the layers of smaller atoms, including an FCC to HCP transition. In a system with (111) texture, a coherent interface to incoherent interface transformation is observed. Calculations of elastic constants of these multilayer structures show that elastic anomalies are associated with the structural variations.

eng_Latn

Reduction of classical thermal conductivity under the influence of high‐power lasers

Observation of the front and rear plasma expansions from a laser‐irradiated thin film has been used to study the thermal conduction of polystyrene targets. The existence of reduced conductivity has been inferred above a threshold of 1014 W/cm2. The percentage of laser radiation transmitted through the thin film decreased by an order of magnitude as the laser flux increased from 1013 to 1014 W/cm2.

AbstractThe present paper reports on the production of oxide coatings on an aluminium alloy by microplasma oxidation and on their properties. The surface characteristics of the coatings were determined by surface and structural analytical techniques, i.e. SEM and X-ray diffraction. Thermo-analysis of the coatings was evaluated by means of differential scanning calorimetry and thermogravimetric analyses. It was ascertained that the coatings with a mixture of crystallised γ-Al2O3 and α-Al2O3 have significant microhardness, good electric resistance and good thermostability.

eng_Latn

Photoluminescence of the PbS quantum dots fabricated by the Langmuir-Blodgett technique

The optical and structure properties of the PbS nanoclusters in the Langmuir-Blodgett matrix as well as their properties after the matrix removal in the ammonium atmospheres have been studied. According to the electron microscopy data, it has been established that there are PbS nanoclusters formed on the surface of the samples. It has been found that the matrix removal results in a significant enlargement of the PbS nanocrystals accompanied by the shift of the luminescence into the infra-red range. It has been shown that the PL intensity of PbS quantum dots (QDs) in the matrix decreases with the temperature decrease due to the carrier transfer into defect QDs whereas the the luminescence intensity of the PbS nanocrystals without a matrix grows at the temperature increase.

Abstract A simple pseudopotential (PP) model developed by us earlier was used here to study lattice dynamics and lattice statics of copper. Comparison of the accuracy attainable in different model calculations of the off-symmetry phonon frequencies was made, and the PP model appeared to be at least as accurate as the embedded atom method (EAM). We suggest that calculation of further lattice properties is necessary to evaluate any microscopic model properly. As an example we give a brief review of the PP model application in the lattice dynamics of alloys including the calculation of frequency shifts in different palladium-based alloys.

eng_Latn

A nucleation model associated with phase transitions in the indium-rich and Au-Cu-Zn alloys

This paper is concerned with the calculation of the critical radius and the wavelength of modulation associated with the strained inclusion during first order phase transition. For this purpose the forth order spatial gradient term was included into the free energy density inside the inclusion. Numerical results were obtained for indium-rich alloys such as In-21 at.% Tl, In-4.4 at.% Cd and In-(13−X) at% Pb-X at.% Sn, and also the alloy Au-30 at.% Cu-47 at.% Zn. The effect of the temperature and the atomic fraction of alloying element on critical radius and wavelength of modulation is also discussed and compared to the experimental results.

Abstract An experimental study of convective effects in horizontal zone melting of InSb at large inertial accelerations (up to 30 times earth gravity) is reported. The experiments were carried out on a centrifuge arrangement which permits to vary the driving force of convection in a wide range. The occurrence of temperature fluctuations in the melt zone and of doping striations in the growing crystal is investigated in dependence on resulting acceleration. This is explained by unsteady convection which is discussed in relation to existing theoretical work. A suppression of unsteady convection and doping striations at large acceleration is reported which has been observed for the first time in horizontal zone melting.

eng_Latn

Conductive Interactions of a Wrinkled Flame with a Cold Flat Burner

Abstract We study the dynamics of a wrinkled flame held downstream of a cold, isothermal, flat burner The analysis is conducted in the framework of a thermal diffusional flame model. An Arrhenius rate with a large activation temperature and a single reactant with Lewis number unity are postulated We show that the nonlinear evolution equation for the front shape and position is no longer local, neither in time nor in space, when the flame is sufficiently close to the burner surface.

Abstract In this letter, we report clear correlations between the glass transition temperature Tg, the crystallization temperature Tx, the Curie temperature TC and the electronegativity based on statistically analyzing more than 200 kinds of soft magnetic Fe-based amorphous alloys. The underlying physical origin of these correlations is discussed. Based on these correlations, the influences of various alloying elements are classified. These results are helpful for designing new soft magnetic amorphous alloys with high thermal stability.

eng_Latn

Latent heats of phase transformations in iron and steels

The latent heat and the temperature of phase transformations in iron and steel have been measured by differential scanning calorimetry (DSC). The samples were provided in the form of cylinders 3 mm in diameter and 3 mm long. The tests on the DSC apparatus were conducted with a heating process to 1000 °C at a constant rate of 5 °C min - 1 and with a cooling process to 300 °C at the same rate. The latent heat of A 3 transformation of iron on heating was 16 kJ kg - 1 and on cooling 19 kJ kg - 1 . The relationship between the temperature of phase transformation and the carbon content of the steel was examined and made clear. For carbon steel, the latent heat on heating and cooling approximately correlated with the carbon content.

Abstract We present a magneto-optical study of p -type Zn 1− x Mn x O diluted magnetic semiconductors (DMS) obtained by thermal oxidation Zn 1− x Mn x Te layers. Photoluminescence spectra were used to determine the “giant” Zeeman splitting and to estimate the exchange integrals N 0 (α−β)∼0.1 eV. This is an extremely small value for a II–VI DMS, and we discuss possible reasons for this effect.

eng_Latn

Aluminum coated steel pipe material with brazing filler metal

The invention provides an aluminum coated steel pipe material with brazing filler metal, which can solve the problems that the production cost is high, and the processing difficulty is high for producing straight cold air coolers by the existing aluminum coated steel pipes. The aluminum coated steel pipe material with brazing filler metal comprises carbon steel as a core material and a skin material; the skin material and the core material are combined and connected. The aluminum coated steel pipe material with brazing filler metal is characterized in that the skin material comprises an aluminum alloy brazing filler metal layer and a connecting layer which are connected in a hot rolling and bonding mode, and the connecting layer and the surface of the core material are combined.

Introduction It is well known that Ni catalysts are very useful for many catalytic reactions. But the size of Ni particles on catalyst is typically 20-100 nm and the preparing the smaller Ni particles on the support is desired. Colloidal metal particles have been expected as a superior catalyst precursor for supported solid catalyst because of their small particle size and the narrow size distribution. In this study, we prepared Ni metal colloid by using tBuONa as a stabilizer and used for the Ni catalyst precursor. Non-porous SiO2 as well as meso-porous SiO2 (HMS) were used as the support. The supported Ni catalysts were reduced by hydrogen and were characterized by XAFS analysis.

eng_Latn

Wear Resistance of High Frequency Pulse Electroplating Ni-SiC Nano-Composite Coating

The Ni-SiC nano-composite coatings were prepared on the ring of stainless steel by using of high frequency pulse electroplating. Orthogonal experiment was used to study optimal dosage of the dispersant. The effect of some factors, such as current density, pH value, temperature , addition agent and so on, were studied. The characterization of Ni-SiC nano-composite coatings were studied by wear test. The effect of pulse frequency and the SiC concentration in the electrolyte on the wear resistance of Ni-SiC nano-composite coatings were studied. The morphology of the nano-composite coatings in wear test before and after were analyzed by SEM and the metaloscope photographs. The results show that Ni-SiC nano-composite coatings of high frequency pulse electroforming have better performance of wear resistance.

We determine from a two-band Hubbard Hamiltonian the spin susceptibility and the self-energy for the holes in the CuO 2 planes. From this, the quasiparticle lifetime τ, the spectral density, the electrical resistivity p resulting from spin scattering, and the NMR relaxation rate l/T 1 at Cu sites are calculated. Our results, which are expected to be valid for larger hole doping, are in reasonable agreement with experiment and indicate that an interplay of narrow-band phenomena and spin fluctuations leads to the observed anomalous normal-state properties

eng_Latn

Anisotropic Elastic Constants of Copper Thin Films: RUS/Laser and Picosecond‐Laser Ultrasound

We propose a combination of the RUS/laser method and picosecond‐laser ultrasound method for measuring anisotropic elastic constants of thin films. The RUS/laser method determines the in‐plane moduli, C11, C12, and C13, of thin films; and picosecond‐laser ultrasound method determines the out‐of‐plane modulus, C33. Therefore, their combination enables us to evaluate elastic anisotropy of thin films. In this study, we measured the elastic constants of copper thin films. They showed elastic anisotropy between the in‐plane and out‐of‐plane directions. This is attributed to columnar grain structure and noncohesive bonds aligned at the columnar grain. This view is supported by micromechanics calculation.

Abstract The inelastic response of primary containment to a high-energy axisymmetric excursion is found by numerical techniques. First, the equation of state of inelastic behavior is discussed. Then the basic conservation laws of mass, momentum, and energy are given in Eulerian coordinates. These equations are then transformed into Lagrangian cooridinates and the finite difference equations for numerical computation. Finally, the results of a sample problem calculation are given.

eng_Latn

Phase diagram and thermodynamic properties of Ag−Cu alloys

Interactive laws of the components described by Gibbs energy functions of CC theory are different from each other, but each G-function can be used to draw the phase diagram of Ag−Cu system with almost the same accuracy. The partial molar properties of the components obtained from all these G-functions are identical. This shows the defects of thermodynamics of alloys. The thermodynamic properties of Ag−Cu alloys and their components have been calculated by the correct G-function which is chosen through a relative study of the energy, volume, atomic arrangement and electronic structure.

We demonstrate GaSb overgrowth over tungsten patterns and that selective area epitaxy is achievable in the W/GaSb system. By controlling the facet growth at low temperatures, it is possible to embed a metal grating in a thin layer.

eng_Latn

The characterization of borided pure tungsten

This study reports on mechanical properties of borided pure tungsten. Boronizing heat treatment was performed in a solid medium consisting of Ekabor powders at 940 °C for 2, 4, and 8 h. The presence of WB on the surface of pure tungsten was confirmed by XRD analysis. Metallographic studies revealed an almost uniform and compact boride layer on the surface of the pure tungsten. The thickness of boride layer ranged from 10 to 42 μm with some scatters. The hardness of borided specimens decreased with the distance from the surface to the interior of the test material. The hardness of the boride on the substrate was 2500 HV while the hardness of the substrate was 445 HV.

In the footsteps of our previous work \cite{RamatonBoschi} we generalize the Stefan-Boltzmann and Wien's displacement laws for the $ \textrm{AdS}_5 \times {\cal S}^5 $ spacetime, the background of the AdS/CFT correspondence foremost realization. Our results take into account the $ \textrm{AdS}_5 \times {\cal S}^5 $ full dimensionality in the electromagnetic field $A^{\mu}$ wave equation, which yields the higher-dimensional blackbody characteristic features suggested in literature. In particular, the total radiated power and the spectral radiancy match the original Stefan-Boltzmann and Wien's displacement laws in the low-energy regime up to available experimental data.

eng_Latn

High-resolution electron microscope study of the ordered lead-calcium titanate ceramics

High-resolution electron microscopy (HREM) has been used to demonstrate the structural characteristics of ordered (Pb0.5Ca0.5) TiO3. The fine structure of both ordered and disordered domains was exposed in lattice level. It was shown that there are 1/2 {111}, 1/2 {110} and 1/2 {111} ordering coexisted in (Pb0.5Ca0.5) TiO3 and all of them are chemical ordering due to the layers of Pb2+ and Ca2+ cations align alternatively along different directions. For 1/2 {111} chemical ordering, a special type of boundary defined as “vernier boundary” was introduced.

The formation of dense layers of slag crust in a rotary furnace when normal electrocorundum sludge is used in the charge to make mullite-corundum fireclay depends on the chemical-mineral composition of the charge and the components of the crust, wetting processes, and the effect of lower compounds of titanium on the physico-chemical processes which take place.

eng_Latn

A New Correlation for Pressure Drop in The Cooling Process of AL2O3-Water Nanofluid in Pipes

This paper discusses the pressure drop of Al2O3-water nanofluid in laminar flow regimes in circular pipes at different temperatures and Al2O3 volume concentrations in both cooling and heating processes. The traditional correlation for calculating pressure drop fails to accurately estimate the pressure drop for laminar flows in cooling processes, but for heating processes there is good agreement with the traditional correlation. Accordingly, this study developed new empirical correlations for calculating friction factors in laminar flows in cooling processes at higher volume concentrations (0.5%). This study found that Al2O3-water nanofluid enhances pressure drop and that temperature rise also reduces pressure drop. The maximum deviations between calculated new correlation and experimental results were reduced to within the -13.64% to +9.98%..

A mathematical model is developed for simulating the formation and growth of phases in the diffusion of aluminum through the nickel matrix of high-temperature alloys. The kinetic laws of diffusion processes in multiphase coatings deposited from a gaseous phase by the method of circulation are determined. The suggested mathematical model is tested experimentally.

eng_Latn

A Convolution Neural Network for Parts Recognition Using Data Augmentation

In order to solve the problem of classifying different kinds of parts automatically, a simplified convolutional neural network was designed. Firstly, image data of the parts that were going to be classified were collected, and were divided into training dataset and testing dataset. Then, a simplified convolutional neural network that was suitable for part recognition was designed. A data augmentation method was raised to augment both train data and test data. The result of the prediction was got by voting. The accuracy was highly improved after the data augmentation was used. The method in this paper classified 29 different sizes of screws, nuts and washers successfully, and validates that data augmentation can improve the performance of the network strongly when the dataset is not big enough.

We present a computer simulation study of thin crystalline multilayers constructed from two FCC solids with differing lattice constants and binding energies. Both materials are described by Lennard-Jones interatomic potentials and initially have the same orientation and coherent interfaces. We have studied systems in which interfaces are perpendicular to the common [100] and [111] directions, respectively. A novel technique for analyzing local atomic ordering, Common Neighbor Analysis, is used to identify structural characteristics in these systems. We have found several structural changes in the layers of smaller atoms, including an FCC to HCP transition. In a system with (111) texture, a coherent interface to incoherent interface transformation is observed. Calculations of elastic constants of these multilayer structures show that elastic anomalies are associated with the structural variations.

yue_Hant

Phase Equilibria in the Aluminum Corner of the Al–Ti–Pt System

A series of physicochemical analysis techniques are employed to study the phase equilibria in the aluminum corner of the Al–Ti–Pt system at subsolidus temperatures and in the alloy crystallization process. It has been established for the first time that a ternary τ1 phase (AuCu3 structural type) forms by peritectic reaction L + + ⇄ τ1 at 1405°C. On the solidus surface in the studied composition range at 1405, 1310, 1275, 1060, 925, 820, and 660°C, there are seven isothermal planes that participate in invariant four-phase equilibria involving the liquid phase, three of them being peritectic and the others transitional.

Problems associated with the modelling and calculation of quasi-steady-state postfault regimes are considered for abrupt power unbalances. A program permitting calculation of quasi-steady-state postfault regimes with allowance for frequency dynamics and the investigation of their stability is described. Results of calculations based on this program are compared with experiments using an electrodynamic model. It is shown that allowance must be made for frequency dynamics in the analysis of postfault regimes. 9 refs.

eng_Latn

Structural and dielectric properties of Ba5LnSn3Nb7O30 (Ln=La, Nd) ceramics

Abstract Two novel Ba 5 LnSn 3 Nb 7 O 30 (Ln=La, Nd) ceramics were prepared and characterized. Both compounds are paraelectric phases adopting the filled tetragonal tungsten bronze (TB) structure at room temperature. Ba 5 LaSn 3 Nb 7 O 30 and Ba 5 NdSn 3 Nb 7 O 30 ceramics show high dielectric constant of 171 and 182 together with low dielectric loss 1.2×10 -3 and 1.8×10 -3 at 1 MHz, respectively. In comparison with dielectric ceramics with TB structure in BaO–Ln 2 O 3 –TiO 2 –Ta 2 O 5 (Ln=La, Nd) system, the temperature coefficients of the dielectric constant ( τ e ) are significantly reduced.

We investigated the thermal stability of e-beam deposited Mo/B 4C/Si/B 4C layered systems, with and without ion assistance during the growth of the B 4C diffusion barrier layers. The thermal stability was investigated by in situ thermal annealing during grazing incidence X-ray reflection. By studying partially treated B 4C barrier layers, we found that the improvement in thermal stability is caused by an enhanced density of the B 4C layer. © 2012 American Institute of Physics.

eng_Latn

Preparation and Damping Properties of NiCrAlY Coating by Arc Ion Plating

NiCrAlY coatings were prepared on stainless steel substrates by arc ion plating technique.The coating samples were tested in phase,surface morphology,micro-determination chemical composition,storage modulus and loss modulus.The results showed that uniform NiCrAlY coating can be fabricated on steel substrate by arc ion plating technique.The variation of arc current during the preparation influenced the surface topography and chemical constitution of the coatings to a certain extent,while the influence on the sample phases was not observed.The testing results of storage modulus and loss modulus were obtained to study the damping characteristics of NiCrAlY coatings.It approved that the damping properties of the substrates are prominently ameliorated by NiCrAlY coating.

Abstract Cation concentration profiles in solid—solution scales on NiCo alloys have been calculated by making use of Wagner's theoretical analysis. As a result of the computation method used, it becomes unnecessary to incorporate experimental values in the calculation for either the parabolic rate constant, k p , or the boundary conditions of the cation profile. The agreement between the independently determined theoretical and experimental cation profiles provides strong support for Wagner's model. The calculated variation of k p with alloy composition is also in agreement with the experimental data.

eng_Latn

Fatigue life of preceramic soldered and postceramic soldered joints.

This research investigated the fatigue life (ie, the number of cycles of a given stress that can be sustained by a sample prior to catastrophic failure) of metal ceramic soldering. One metal ceramic alloy was joined using four postceramic solders and one preceramic solder. All specimens received appropriate heat treatment simulating ceramic application although no porcelain was applied. Five specimens were fabricated for each solder type, and a 35,000 psi (241.4 MPa) fatigue stress was applied to each solder joint during specimen testing. The test variable was the number of stress cycles required to fail each specimen. The postceramic solders exhibited significantly higher fatigue lives than did the preceramic solder. Scanning electron microscope analysis showed that the preceramic solder not only exhibited a larger grain size, but also showed micropores between these grains.

Abstract The moving parts of any mechanism and machine parts are always subjected to a significant wear due to the development of friction. It is utmost important aspect to address the wear problems in present environment. But the complexity goes on increasing to replace the worn out parts if they are very precision. Technology advancement in surface engineering ensures the minimum surface wear with the introduction of polycrystalline nano nickel coating. In this study, tribological behavior of the nano nickel coating developed through pulsed electro deposition technique has been investigated. The nano structured coated specimen were admitted for pin and disc method of wear testing. The nature of wear has been examined over the surface of the specimen through Atomic Force Microscope (AFM) in order to validate the prior results. The results yielded from pin and disc and AFM registered the negligible deviations.

eng_Latn

Enhancement Effect of Combining Interaction with Comparison on Teaching of Heat Transfer and Absorption

Using the method of combining interaction with comparison,the similarities and differences of heat transfer and absorption in Principles of Chemical Engineering were summarized in review sections.This method was effective for students to understand and master the basic concepts of heat transfer and absorption,which created a better teaching atmosphere and was helpful to improve the students' ability to analyze and solve the problems,and the enthusiasm and initiative for the study of Principles of Chemical Engineering.

Abstract In this letter, we report clear correlations between the glass transition temperature Tg, the crystallization temperature Tx, the Curie temperature TC and the electronegativity based on statistically analyzing more than 200 kinds of soft magnetic Fe-based amorphous alloys. The underlying physical origin of these correlations is discussed. Based on these correlations, the influences of various alloying elements are classified. These results are helpful for designing new soft magnetic amorphous alloys with high thermal stability.

eng_Latn

Magnetic properties of Ni(NO3)2•2H2O

Abstract This work is concerned with the magnetic properties of Ni(NO 3 ) 2 ·2H 2 O from ( H in - T ) and ( H ap - T ) phase diagrams. From these diagrams we have obtained the values of H c (0), T N and T t . A comparison between experimental and theoretical values of T t is made, where a T t relation for a spin 1 metamagnetic model is found.

NiCrAlY coatings were prepared on stainless steel substrates by arc ion plating technique.The coating samples were tested in phase,surface morphology,micro-determination chemical composition,storage modulus and loss modulus.The results showed that uniform NiCrAlY coating can be fabricated on steel substrate by arc ion plating technique.The variation of arc current during the preparation influenced the surface topography and chemical constitution of the coatings to a certain extent,while the influence on the sample phases was not observed.The testing results of storage modulus and loss modulus were obtained to study the damping characteristics of NiCrAlY coatings.It approved that the damping properties of the substrates are prominently ameliorated by NiCrAlY coating.

eng_Latn

First-principles study of conduction through a sodium atomic sheet

Electronic conduction in an atomic sheet is examined theoretically from first principles as an example of a typical two-dimensional system. The conductance per atomic chain, calculated assuming a bias voltage of 0.1 V, is 0.87 G0 for the atomic sheet, which is lower than for the corresponding single chain (1.0 G0; G0 = 2e2/h). The difference is attributed to a reduction of the local density of states around the Fermi level, particularly in the region where the bridge comes into contact with the electrode. [DOI: 10.1380/ejssnt.2006.507]

Recently it has been possible to obtain very pure (99.999+%) metals at a very reasonable cost due to the development of improved large scale purifying processes(1). Studies may now be performed cheaply on pure single crystal specimens of a type approximating the “ideal” specimen assumed in most theories of normal and superconducting metals. In this lecture we summarize the results obtained from experiments involving the superconducting properties (and some normal state properties) of such materials. These results are indicative of the new and interesting phenomena one might observe in very pure single crystal specimens. We will discuss only our own results, for reasons of time limitation and familiarity, although similar data are now found with increasing frequency in the literature.

eng_Latn

THE TENSILE STRENGTH OF SOME REFRACTORY METALS AT HIGH TEMPERATURES

The tensile strengths of the refractory metals niobium, tantalum, tungsten, and molybdenum were measured in the range 0 to 2300 deg C. Up to 800 C a standard Hounsfield tensometer was used, but from 800 to 2200 deg C the measurements were made in a carbon-tube vacuum furnace. The behavior of these metals was comparable in every respect, at equivalent homologous temperatures, with that of the lower-melting-point metals. The upper temperature limit was imposed by a reaction between carbon vapor from the furnace tube and the specimen. Above 2000 deg C a carbide was formed on the surface and diffused into the specimen, thereby affecting the mechanical properties appreciably. (auth)

We study the basic properties of tensor random fields (TRFs) of the wide-sense homogeneous and isotropic kind with generally anisotropic realizations. Working within the constraints of small strains, attention is given to antiplane elasticity, thermal conductivity, classical elasticity and micropolar elasticity, all in quasi-static settings albeit without making any specific statements about the Fourier and Hooke laws. The field equations (such as linear and angular momentum balances and strain–displacement relations) lead to consequences for the respective dependent fields involved. In effect, these consequences are restrictions on the admissible forms of the correlation functions describing the TRFs.

yue_Hant

Effects of Aging Temperature on Microstructure and Thermal Properties of CuAlMn Shape Memory Alloys

The use of copper-based shape memory alloys is increasing rapidly. In this study, the aging effects of CuAlMn shape memory alloys were investigated. Three different alloys were produced during the work. These alloys were then aged for one hour at temperatures of 200 ° C, 300 ° C, 400 ° C and 500 ° C. DSC, XRD and microstructural investigations were carried out on samples which were not aged and aged at different temperatures. Experiments have shown that aging at high temperatures has an adverse effect on shape memory effect on alloys.

Quantitative texture analysis, including calculation of the orientation distribution function, is used to demonstrate textures in alumina hot-forged at 1800°C. As suggested by earlier investigations, strong basal textures can be produced by pressing and forging alumina. Experiments in plane strain support arguments for slip-based texture development. Since the earlier investigations provided incomplete information on preferred orientation, a comparison is made of current and past procedures used to report textures in alumina.

eng_Latn

Theoretical study of a melting curve for tin

The melting curve of Sn has been calculated using the dislocation-mediated melting model with the 'zone-linking method'. The results are in good agreement with the experimental data. According to our calculation, the melting temperature of γ-Sn at zero pressure is about 436 K obtained by the extrapolation of the method from the triple point of Sn. The results show that this calculation method is better than other theoretical methods for predicting the melting curve of polymorphic material Sn.

A sampling cone 3 and/or a cone gas cone 4 and/or an extraction cone 8 of a mass spectrometer are disclosed having a metallic carbide surface or coating. The metallic carbide surface or coating may comprise a transition metal carbide, a carbide alloy, or a mixed metal carbide alloy, but preferably comprises titanium carbide. The coated surface is intended to reduce adsorption of material on contact with the surface of the sampling or extraction cone.

eng_Latn

A high strength, heat treatable aluminum alloy

A high strength aluminum alloy is suitable for ultra thick gauge wrought product. The alloy can have 6 to 8 wt % zinc, 1 to 2 wt % magnesium, and dispersoid forming elements such as Zr, Mn, Cr, Ti, and /or Sc with the balance made of aluminum and incidental elements and/or impurities. The alloy is suitable for many uses, including in moulds for injection-molded plastics.

We report the yield and D/H of water released by stepped heating of bulk Shergotty, Zagami, Chassigny, and the newest martian meteorite, ALH 84001. For comparison, we also report data from Nakhla using the same procedure since the heating steps in this study are slightly different than our previously reported nakhlite analyses.

eng_Latn

X-ray absorption study of the GeSe system: II. GeSey glasses: Bulk and thin film samples

Abstract EXAFS measurements on Se Ge ratios greater than 2 have been undertaken for different forms of the GeSe y family, bulk or thin films. Data analysis was made both at the Ge and Se K edges and special attention was first paid to the effect of the grain size on the absorption amplitude. The results of the various investigations led to the conclusions that if the germanium tetrahedral environment is constant, that of selenium varies strongly between (i) GeSe 3 and GeSe y , y > 3, and (ii) bulk phases and thin films. A model taking into account these differences is discussed, explaining these changes by the existence of selenium clustering in the more enriched Se compositions.

This article describes screening of fine granular materials, including minerals. The first part of the study presents a description of screening and an analysis of resulting conclusions. The second part describes screens that have been developed in Lodz Technical University labs. From a number of screens only three have been chosen and described in this article. Additionally, results of some pilot-plant-scale tests involving these screens made at Lodz Technical University are discussed. Experimental tests covered first motion of the sieves, and then the process of screening on these sieves. Results are presented both in a graphic form as diagrams and in the analytical form as correlations.

eng_Latn

A thermal cycling reliability study of ultrasonically bonded copper wires

In this work we report on a reliability investigation regarding heavy copper wires ultrasonically bonded onto active braze copper substrates. The results obtained from both a non-destructive approach using 3D X-ray tomography and shear tests showed no discernible degradation or wear out from initial conditions to 2900 passive thermal cycles from − 55 to 125 °C. Instead, an apparent increase in shear strength is observed as the number of thermal cycles increases. Nanoindentation hardness investigations suggest the occurrence of cyclic hardening. Microstructural investigations of the interfacial morphologies before and after cycling and after shear testing are also presented and discussed.

The interconversion of mononuclear AuI/II/III centres in thioether macrocyclic complexes is related to the stereochemical properties of the parent AuI species; the structure of [Au([18]aneS6)]+ shows a distorted tetrahedral [2 + 2] coordination at AuI, while the AuI complex of [15]aneS5 is binuclear with AuI ions bridging [15]aneS5 ligands in a macrobicyclic structure.

eng_Latn

Impact Influence on Deposited Metal of Flux-cored Wire DG7

The shield machine cutter suffers from strong im- pact and grain-abrasion in high stress when it works in Bei- jing.The cutter wears down quickly and the import cutter's drive life is about 250 meters.Flux-cored wire named DG7 was developed for the cutter's repair and reproducing.The cutter's drive life in drive testing reached 780 meters when it was improved by DG7.The article impactes DG7's deposited metal different times by different weight shots and tests the transformation of the deposited metal's hardness,microstruc- ture and anti-abrasive performance.

(Received 19 June 2011 ; in final form 25 February 2012) Abstract In this study, we investigated the spin dependent electronic transport of a fishbone-like nanostructure including two magnetic atoms at its ends. The electronic conductance of this nanostructure for three different orientations of atomic magnetic moments was numerically studied when the structure was sandwiched between two nonmagnetic leads. By using Green’s function technique at the tight-binding model, we calculated the spin dependent electronic transmission coefficient. The calculated results revealed that the conductance depends on the incident electron energy as well as the magnitude and orientation of atomic magnetic moments in the nanostructure.

eng_Latn

Damping Evolution During Precipitation in Al-Mg-Si Alloys

Damping capacity and shear elastic modulus measurements have been carried out during precipitation in AlMgSi alloys. After the specimen has been aged at the temperature corresponding to the lowest thermoelectric power, both damping and elastic modulus increase comparing with the as-quenched state. The effect of strain amplitude was investigated in specimens aged at different temperatures. A critical strain amplitude, e c , has been observed. For strain amplitudes higher than e c , the damping capacity increases strongly with strain amplitude. In addition a relaxation peak appears around 420K after ageing. The strong damping-amplitude effect and the relaxation peak are attributed to the breakaway of the dislocation from the solute atoms at low temperature and to the dragging of these solute atoms by the dislocations at high temperature respectively.

Background and aims ::: Arabidopsis halleri is a pseudometallophyte plant model hyperaccumulating zinc and cadmium. This study investigates which abiotic parameters may cause phenotypic divergence among accessions for hyperaccumulation traits.

eng_Latn

Growth of Al2O3/Y3Al5O12 Eutectic Fiber by Micro-Pulling-Down Method and Its High-Temperature Strength and Thermal Stability

Fiber growth of Y3Al5O12 (YAG) matrix composite reinforced with the sapphire phase was investigated to manufacture sapphire/YAG eutectic composites using the micro-pulling-down (µ-PD) method. Both the sapphire and YAG phases were crystalline. We have controlled the fiber diameter from 200 µm to 2 mm. The maximal length was about 500 mm. The eutectic fibers have superior high-temperature strength properties, 580 MPa at 1500°C. In the tensile test at this temperature, the fiber showed considerable (about 10%) plastic deformation due to dislocation motion. The microstructure of this eutectic fiber has a very high thermal stability. No grain growth was observed after even 75 h of heat treatment at 1500°C in air atmosphere.

Upstream Electromigration (EM) study was performed on different multiple via structures with different Cu line dimensions. EM performance was found to be dependent on both via layout and Cu line dimension. Failure analysis showed different EM failure modes and diffusion paths on these structures with their different grain morphology. Finite element analysis is applied to find out the current density profiles of these structures and explain their EM results. Simulated resistance increase was found to be dependent on the size and location of EM induced void in these structures.

eng_Latn

Stress Relief Cracking in Heat-Affected Zone (Report 1)

Heat-affected zone cracking due to stress relief heat treatment has been investigated on a wide variety of ferritic steels by simple welding tests and a bend restraint SR cracking test.The results indicate that intercrystalline cracking may occur during the heat treatment ; local stress raisers are necessary to initiate this cracking ; this cracking may not occur in deposited metal and parent metal inaffected ; and susceptibility to cracking depends markedly on chemical composition.Suggested remedies for the cracking problems are : the use of (1) buttering technique prior to welding, (2) grinding off the excess weld metal to remove the notch of the weldment before stress relieving, and/or (3) preventive bead technique before stress relieving.

We study the relaxational dynamics of the one-spin facilitated Ising model introduced by Fredrickson and Andersen. We show the existence of a critical time which separates an initial regime in which the relaxation is exponentially fast and aging is absent from a regime in which relaxation becomes slow and aging effects are present. The presence of this fast exponential process and its associated critical time is in agreement with some recent experimental results on fragile glasses. @S0163-1829~96!04426-8#

eng_Latn

The Reaction between Alkali Vapor and the Theoretical Composition MgAl2O4

The theoretical composition was made from MgO-rich MgAl2O4 (MR66) and alumina powder. The static crucible method was used to study alkali-resistance of the block samples. It has been observed that alkali steam permeated into the hole and reacted with corundum particles that produced β-Al2O3 by means of XRD, SEM and EDS. It led to volume expansion, cracks and melting erosion of corundum particles. The specimen of the 32% content of MgO has good physical and chemical properties and excellent alkali erosion performance. So the specimen is suitable for oxy-fuel combustion for glass melting furnace.

A mathematical model is developed for simulating the formation and growth of phases in the diffusion of aluminum through the nickel matrix of high-temperature alloys. The kinetic laws of diffusion processes in multiphase coatings deposited from a gaseous phase by the method of circulation are determined. The suggested mathematical model is tested experimentally.

eng_Latn

RESEARCH PROGRESS OF FIVE-FOLD SYMMETRY CLUSTERS

Since 1984, Shechtman et al. published a paper which marked the discovery of quasicrystals. The local five fold symmetry (LFFS) structure is becoming an unsocial hero, who walks a muricated way against classical crystallography. As well known, the LFFS clusters have largely potential application prospect in catalysis, in recomposing physical, mechanical and eYVcAR)aVcWCcAR_TVCWSf)?AVeR))ZTX)RddVdZ_TCAaCdZ_XodfaVcReCApAReVcZR)dZ_dCAV creative manufacture technologies of crystal metal from amorphous straightly. In this paper, we summarize the ubiquitous existence, particularity, performance and research progress of LFFS clusters in metallic glasses, and put forward some urgent problems.

To work in a center hole fixrure problem of Italian S530 exists for the product scratch point,the linkage mechanism for the study,three-dimensional design software by Pro/Engineer 4.0 exercise of its movement mechanism simulation analysis gripper movement trajectories and parts scratched the real reasons for the further transformation of the structure of the fixture,fixture work solve the process of scratching the bottom of the problem,on the basis of kinematics simulation summarized Pro/E4.0 mechanical maintenance process in the modern areas of application

yue_Hant

Pion Interferometry in Au+Au Collisions at the Ags

Two-pion Bose-Einstein correlations have been studied using the BNL-E866 Forward Spectrometer in 11.6 A {center_dot} GeV/c Au + Au collisions. The data were analyzed using three-dimensional correlation parameterizations to study transverse momentum-dependent source parameters. The freeze-out time and the duration of emission were derived from the source radii parameters.

Abstract In this letter, we report clear correlations between the glass transition temperature Tg, the crystallization temperature Tx, the Curie temperature TC and the electronegativity based on statistically analyzing more than 200 kinds of soft magnetic Fe-based amorphous alloys. The underlying physical origin of these correlations is discussed. Based on these correlations, the influences of various alloying elements are classified. These results are helpful for designing new soft magnetic amorphous alloys with high thermal stability.

eng_Latn

Gradient nature shaping of the 20X2H4A steel structure as a carbonitriding result

The study of the shaping of the gradient structure nature appearing in constructional alloy martensite 20X2H4A steel (0.2%C, 2%Cr, 4%Ni), as a result of surface saturation by carbon and nitrogen (carbonitriding) at 920℃ in industrial conditions is made in present work by methods of optical and transmission electron microscopy.

A hybrid hydrazine–nitroxide monoradical and the corresponding heterohydrazyl– nitroxide diradical were used as probes in 4-cyano-4′-pentylbiphenyl liquid crystal. EPR data (hyperfine constants, rotational time, and anisotropy parameter values) are reported in the range of 25°C–55°C. It was shown by EPR spectrometry that the nitroxide moiety gives an anisotropic triplet line, while the hydrazyl moiety cannot be detected under these conditions.

eng_Latn

pH’s Effection to Electroplating Ni-SiC Plating on Aluminum Alloy

This study is of aluminum alloy electroplating process pH alloy electroplating Ni-SiC properties. Research shows that the results show that, when the bath pH for 4.0, plating coating uniform structure, compact, the best performance, coating and maximum SiC content.

An investigation was made of how the conditions of formation affect the porous structure, sorption properties and strength properties of nanocomposite sodium alginate fibres. It was found that the sorption properties of these fibres are determined by the hydrophilic nature of the material. The strength properties, given low deformability at the stretching stage, depend mainly on the value of the as-spun draw ratio. In SEM+EDS testing the presence of the natural hydroxyapatite (HAp) or SiO2 nanoadditives which had been added to the fibres was detected.

eng_Latn

Influence of Nitrogen Flows on Properties of CrAlN Film Prepared by Mid-frequency Unbalanced Magnetron Sputtering

CrAlN films were deposited by mid-frequency unbalanced magnetron sputtering in order to study the deposition rate,composition,structure,mechanical features and corrosion resistance as a function of nitrogen flow compared with CrN film.The results show CrAlN films present higher hardness value,denser structure and better corrosion resistance as compared with CrN film.With the nitrogen flow increasing,the deposition rate of CrAlN films is decreasing and Cr/Al ratio increasing,the relative intensity of the(200) peak increases and hexagonal crystalline AlN disappears.In addition,the roughness of CrAlN film decreases from 39 nm to 10 nm and the corrosion potential increases.When the nitrogen flow comes to 53 mL/min,the hardness of CrAlN film reaches a maximum value and the film shows the best excellent corrosion resistance.

The development of coating materials and processes was carried out with the objective to reduce material degradation in supercritical water. Based on the test results of bulk coating alloys (FeCrAlY and NiCrAl), two coating processes, plasma spray of dense NiCrAlY and pack aluminizing, have been developed to apply coatings to candidate stainless steels and Ni-based alloys. The SCW test results and microstructure characterization of both coating alloys and coated candidate alloys are presented in this short paper.

eng_Latn

Study of the thermal transformations of Co- and Fe-exchanged zeolites A and X by “in situ” XRD under reducing atmosphere

Abstract “In situ” high temperature X-ray diffraction under reducing atmosphere is used for the first time to study the thermal stability and transformations of Co- and Fe-exchanged A and X zeolites. TG-DTA and “ex situ” XRD characterization were also carried out. The temperature of incipient crystallization of metallic phase was found to be 700 °C in Fe-zeolites and 800 °C in Co-zeolites. Moreover, ex situ X-ray experiments, after thermal treatment both under inert and reducing atmosphere, revealed the formation of ceramic phases upon the thermal collapse of the zeolitic framework. Metal nanoparticles were obtained by reduction and the size of metal clusters was found to range between 24 and 40 nm.

1. ::: ::: In the course of the application of the enamel coating to 08sp steel, a diffusion redistribution of elements takes place accompanied by the formation in the metal surface layers of a diffusion zone which lost some manganese and gained silicon, boron, and titanium. ::: ::: ::: ::: ::: 2. ::: ::: The diffusion processes at the metal-enamel interface are accompanied by a change in the mechanical properties of surface layers of steel which can considerably affect its strength. ::: ::: ::: ::: ::: 3. ::: ::: The mechanical properties of surface layers of steel depend on the number of enamel firing cycles.

eng_Latn

Superconformal Electrodeposition in Submicron Features

Superconformal electrodeposition is explained based on a local growth velocity that increases with coverage of a catalytic species adsorbed on the copper-electrolyte interface. For dilute concentration of the catalyst precursor in the electrolyte, local coverage in fine features changes more due to interface area change than by accumulation from the electrolyte, yielding superconformal growth. The model is supported by experiments and simulations of copper deposition in 350--100 nm wide features, helping to explain the influence of adsorbates on roughness evolution.

Abstract The moving parts of any mechanism and machine parts are always subjected to a significant wear due to the development of friction. It is utmost important aspect to address the wear problems in present environment. But the complexity goes on increasing to replace the worn out parts if they are very precision. Technology advancement in surface engineering ensures the minimum surface wear with the introduction of polycrystalline nano nickel coating. In this study, tribological behavior of the nano nickel coating developed through pulsed electro deposition technique has been investigated. The nano structured coated specimen were admitted for pin and disc method of wear testing. The nature of wear has been examined over the surface of the specimen through Atomic Force Microscope (AFM) in order to validate the prior results. The results yielded from pin and disc and AFM registered the negligible deviations.

eng_Latn

Precipitation Behaviors of Rapidly Solidified and Hot Worked Al-Zr Base Alloys

Rapidly Solidified (RS) Al-Zr base splats with various alloy contents were prepared by atomization-splat quenching method to understand the continuous and discontinuous precipitation in the aged alloys. And the RS alloys were consolidated by hot extrusion and swaging to analyze the effect of plastic deformation on the precipitation behavior. Discontinuous precipitation dominated at relatively low temperature in the Al-Zr alloy, whereas both V additions to Al-Zr alloys and hot metal working appeared to suppress the discontinuous precipitation. As continuous precipitation is favored in the grain interiors, the driving force for discontinuous precipitation become to disappear with a further process.

Background and aims ::: Arabidopsis halleri is a pseudometallophyte plant model hyperaccumulating zinc and cadmium. This study investigates which abiotic parameters may cause phenotypic divergence among accessions for hyperaccumulation traits.

eng_Latn

Effect of raw materials and heat treatment on peanut allergy

The allergic reaction of peanuts seriously impacts on health. This article describes the general characteristics of the main allergens in peanut. It specifically introduced several different peanut cultivars and the impact of processing including heating (curing, boiling, frying, and roasting) on peanut allergens. Base on the information, it provides some scientific basis for researches and development of non-allergenic or hypo-allergenic peanut products.

Abstract Composites with aluminium alloy matrix and ceramic reinforcements are popular candidates in automotive, aerospace, defense and other industries because of their high strength-to-weight ratio, stiffness, impact strength, wear resistance, etc. In the present study AA 5083 / Nano SiC composite were fabricated by stir casting. A 2-level Full Factorial design of experiments (DOE) was used to study the influence of process parameters like casting temperature, stirrer speed, and weight percent of reinforcement on hardness of composites. Mathematical model was developed to investigate which parameters significantly affect the hardness of composites. The effect of parameters on the response and adequacy of hardness model developed were tested by employing ANOVA and Fisher’s F-test. This model can be used to select the optimum process parameters for obtaining the composites hardness within the range of experimental frame work.

eng_Latn

Surface diffusion in thin film couples

Abstract A study has been made of surface diffusion in the evaporated thin film couple Ni-Au. Structural changes within the diffusion zone were examined by electron microscopy in situ . Apart from a slight migration of the layers, crystallization was quite pronounced. The results obtained by means of an electron microprobe analyser showed that the diffusion rate was higher than in the bulk.

Abstract In this study, the influences of the changes in fin geometry on heat transfer and pressure drop of a plate fin and tube heat exchanger are investigated, numerically. A computational fluid dynamics (CFD) program called Fluent is used in the analysis. The segment of one tenth of fin is used in the modeling, due to symmetrical condition. The results of heat transfer, static, and total pressure drop values of ten different fins are tabulated and the normalized values of them are, also, given for the comparison of the models. The distance between fins is found to have a considerable effect on pressure drop. It is observed that placing the fin tube at downstream region affects heat transfer positively. Another important result of the study is that increasing ellipticity of the fin tube increases the heat transfer while it, also, results in an important reduction in pressure drop.

eng_Latn

Microstructure Morphology Evolution of Single Crystal Copper Rod by Ohno Continuous Casting in Copper Manufacturing System

Heated-mould continuous casting (Ohno continuous casting, OCC) is a kind of special continuous directional solidification technique in copper manufacturing system. Copper rod solidification process is cooperative controlled by heated mould and water cooler. Single crystal metal rod of any length can be produced by OCC. In this paper, based on continuous nucleation model, microstructure morphology evolution process of single crystal copper rod has been studied by coupled cellular automata method and finite element method. Competitive growth process has been described that tiny equiaxed crystal merged into big columnar crystals towards heat flow direction. Single crystal evolution distance changing rule has been study under different drawing speed and mould temperature by simulation and experiment results. This study provides reference for high quality single crystal copper rod in copper deep manufacturing processing.

Abstract Electronic structure calculations of MS10−6 clusters (M = Mn, Fe, Co, Ni) have been performed making use of the Xα discrete variational method. The results of the calculations are used for the detailed interpretation of the X-ray emission and photoelectron spectra for Mn, Fe, Co and Ni monosulphides and in a discussion of the physical-chemical properties of the compounds under investigation.

eng_Latn

Electrodeposition of PbSe epitaxial films on (111) InP

Epitaxial growth of PbSe is addressed on (111) InP single crystals by electrodeposition from aqueous solutions containing Se(IV), Pb(II) and Cd(II). The structure of the deposits is studied by reflection high-energy electron diffraction and X-ray diffraction. It is shown that an epitaxial growth is only observed in the presence of cadmium in the electrolyte. The best epitaxy is obtained for an optimal 0.5 M cadmium concentration.

While alloy deposition is a frequently studied topic analysis of the alloy phases formed is a complex and often destructive process. In the current study the complex copper–tin alloy system has been studied in deep eutectic solvents using a variety of electrochemical and surface analysis techniques to determine the mechanism of alloy deposition and composition of deposits. The use of electrochemical quartz crystal microbalance is shown to enable real-time monitoring of alloy composition and the latter is shown to be very dependent upon the concentration of ions in solution. For this system X-ray diffraction was also used to study the phase behaviour of the deposits as a function of solution composition and current density. Finally it was shown for the first time that brighteners used for copper deposition in aqueous solutions also work in ionic liquids.

eng_Latn

IU Progress Report January 2013

Abstract : Our group has been working in the following directions: 1. Testing and tuning our time series classification algorithm, 2. Perfectioning the use of entropy in language models as a tool to reconstruct the context of a given meme/conversation, 3. formalizing in an operational sense the definition of campaign and its associated features, 4. collecting relevant datasets to test detection algorithms.

Abstract Some new possibilities of using specular neutron reflection in the study of roughness and interdiffusion in thin-film structures have been proposed and tested (the use of polychromators and supermirrors, direct measurement of the thickness of nonmagnetic interdiffusion layers). A statistical roughness growth law was found to be satisfactory in the interpretation of results, the growth rate being dependent on the materials used, film deposition techniques, etc. The use of ( λ 4 , λ 2 ) -sequences is proposed to increase the sensitivity of the method to the nonmagnetic interdiffusion layer thickness.

eng_Latn

PPE study of water migration in starch sheets under moist atmosphere

The photopyroelectric method in a non contact detection configuration is proposed to study water migration in starch sheets. This allows the exchange of humidity between the moist atmosphere and the starch sample during the experiment. The sensitivity for the total water content measurement was about 0.3%. A theoretical model was developed, taking into account a continuous depth profile of humidity in the starch sample. A water profile in the material and its evolution in time were evidenced when exposing one side of the sample to a humid atmosphere.

1. ::: ::: In the course of the application of the enamel coating to 08sp steel, a diffusion redistribution of elements takes place accompanied by the formation in the metal surface layers of a diffusion zone which lost some manganese and gained silicon, boron, and titanium. ::: ::: ::: ::: ::: 2. ::: ::: The diffusion processes at the metal-enamel interface are accompanied by a change in the mechanical properties of surface layers of steel which can considerably affect its strength. ::: ::: ::: ::: ::: 3. ::: ::: The mechanical properties of surface layers of steel depend on the number of enamel firing cycles.

eng_Latn

Mathematical Simulation of Phase Formation and Growth in Nickel Aluminizing

A mathematical model is developed for simulating the formation and growth of phases in the diffusion of aluminum through the nickel matrix of high-temperature alloys. The kinetic laws of diffusion processes in multiphase coatings deposited from a gaseous phase by the method of circulation are determined. The suggested mathematical model is tested experimentally.

Many physical phenomena can be described by biexponential curve. To study the physical phenomena, there is a need to obtain their mathematical expressions. Generally, the expressions are acquired based on the fitting of experimental data, and the general method to fit exponential curve is nonlinear least squares (NLLS). In the NLLS method, it is crucial to choose good enough starting values for the parameters, otherwise, the fitting might fail to converge. In this paper, one new method is proposed to solve the problem, which utilizes the Fourier transform to transform the non-linear exponential fitting model into a linear one. It makes the estimation of the parameters independent of the initial values and easy to converge. The fitting result shows that the proposed method can be used to fit the curve expressed by difference of double exponentials.

eng_Latn

Molecular dynamics study of the alloy (N2)67(Ar)29

Molecular dynamics calculations are used to investigate the effect of isobaric cooling on the hexagonal alloy (N2)67(Ar)29. Particular attention is given to the behavior of the reorientational motion of the N2 molecules. No orientational or structural transition was found to accompany the cooling from 60 to 10 K at either P = 4 × 103 or P = 1 × 103 bar (1 bar = 100 kPa). However, the power spectrum of the angular-velocity autocorrelation function clearly reveals the freezing out of rotational diffusion at low temperature.

In this paper, an optimization technique based on the Adaptive Response Surface Method (ARSM) is combined with a finite element solution of heat conduction to investigate an aircraft engine cooling problem. The overall purpose of this optimization is to improve the thermal effectiveness of an aircraft deicing strategy. The finite element procedure uses a two-dimensional discretization of an engine intake surface with quadrilateral, isoparametric elements. Based on a comparison between the ARSM predicted results and the plotted objective function, it is observed that the combined techniques provide an effective method for thermal optimization.

eng_Latn

Mg/MmNi5-x(CoAlMn)x Hydrogen Absorption Composite Synthesized by Mechanical Alloying

Mg/MmNi5-x(CoAlMn)x composite hydrogen storage alloy has been synthesized by mechanical alloying.Xray diffraction and SEM have been used to study the microstructure characteristics of the materials.The results showed that Mg/MmNi5-x(CoAlMn)x granule structure was formed after certain milling time.These granules were composed of very fine MmNi5-x(CoAlMn)x particles and magnesium,in which the magnesium acted as binder.According to the Xray diffraction result,the grain size of MmNi5-x(CoAlMn)x and magnesium phases was estimated for the composites of different compositions and milling conditions estimated.

The most widespread lithic elements in manganese nodules are elements of the group of alkaline and alkaline-earth elements, namely, potassium, sodium, calcium, magnesium, barium; elements of the lithogenic group or hydrolysate elements: aluminium and titanium; silicon which is of a polygenic nature (litho- and biogenic); and elements of the biogenic group, namely, carbon, phosphorus and sulphur (we shall also consider nitrogen as being related to this group). We shall also consider pore water, which plays an important role but which is sometimes ignored.

eng_Latn

Corrosion Resistance of Three Arc-sprayed Zinc Coatings in 3.5% NaCl Solution

Pure Zn,Zn-Al alloy and Zn-Al pseudo-alloy coatings were prepared on Q235 steel surface by arc spraying technique.The corrosion resistance of these coatings was investigated by immersion testing and electrochemical measurements in 3.5% NaCl solution.The surface morphology of the samples after test and the phase composition of corrosion products were analyzed by using electron microscopy(SEM) and X-ray diffraction(XRD).The results show that the corrosion resistance of the coatings decreased sequentially in the order of Zn-Al pseudo alloy coating,Zn-Al alloy coating,and pure Zn coating.

The role of ZnS shell on the photo-physical properties within CuInS2/ZnS quantum dots (QDs) is carefully studied in optoelectronic devices. Linearly increasing voltage technique has been employed to investigate the charge carrier dynamics of both CuInS2 and CuInS2/ZnS QDs films. This study shows that charge carriers follow a similar behavior of monomolecular recombination in this film, with their charge transfer rate correlates to the increase of applied voltage. It turns out that the ZnS shell could affect the carrier diffusion process through depressing the trapping states and would build up a potential barrier.

eng_Latn

temperature affects on steel hardness

CONCLUSIONS. The present study of the effect of temperature on the electrodeposition of chromium on 1045 steel showed that the hardness increases while the grain size of the chromium deposited decreased with increase in temperature. Between 50 °C and 60 °C the results showed barely perceptible differences.

Fig 4 Effect of nitrogen on strain ageing index of steel. Effect during welding – Nitrogen generally affects the toughness of the heat affected zone (HAZ) of welded steel. Since the weld metal should not be weaker in a welded structure, the role of nitrogen is important. The loss of toughness is normally known as HAZ embrittlement.

eng_Latn

A Data Mining Approach to Expressive Music Performance Modeling

In this chapter we present a data mining approach to one of the most challenging aspects of computer music: modeling the knowledge applied by a musician when performing a score in order to produce an expressive performance of a piece. We apply data mining techniques to real performance data (i.e., audio recordings) in order to induce an expressive performance model. This leads to an expressive performance system consisting of three components: (1) a melodic transcription component that extracts a set of acoustic features from the audio recordings, (2) a data mining component that induces an expressive transformation model from the set of extracted acoustic features, and (3) a melody synthesis component that generates expressive monophonic output (MIDI or audio) from inexpressive melody descriptions using the induced expressive transformation model. We describe, explore, and compare different data mining techniques for inducing the expressive transformation model.

Dennis M. Ray is a visiting scholar at both the Institute of South-east Asian Studies, Singapore, and the Institute of International Relations, Sophia University, Tokyo, Japan. This research note reports on a pilot study conducted in Singapore to test whether two scales correlated with either the level of exports or the manner in which export sales were pursued by venture business in Singapore. The study suggests that a cross-cultural experience scale along and in combination with the craftsman-opportunist typology modified to fit various culture settings may be a powerful tool for predicting export activity.

kor_Hang