Experimental and numerical study of heat transfer through a synchronous belt transmission type AT10
Highlights • An experimental study on pulley-belt temperature measurement is presented.• The effects of torque, setting tension and angular speed on the belt.• A heat transfer model is proposed to calculate pulley-belt heat flux.• Validation based on experimental thermal surveys and thermocouple measures.• A comparative analysis between two heat fluxes (calculated and simulated) is done.
Stability and coupling dynamic characteristics of a vibrating system with one internal degree of freedom and two vibrators
Abstract In present work the stability and coupling dynamic characteristics for a vibrating system with one internal degree of freedom, driven by two vibrators, are investigated, which is a further extension and innovation of a previous literature. In theory, the responses of the relative and absolute motion of the system are given; the synchronization criterion of the system is obtained based on the average method, and the stability criterion of the synchronous states is derived by Hamilton principle. According to the above theory results, the frequency-amplitude characteristics of the system are discussed qualitatively by numeric, as well as the stable states, phase relationships and corresponding motion types of the system in different resonant regions. The Runge-Kutta routine is employed to verify the feasibility of the used theory method. Finally, an experimental vibrating mill corresponding to the present dynamical model is designed and manufactured, and the experiments are carried out to further examine the validity of the present investigations. It is known that, in order to obtain the reasonable relative circular motion of two rigid frames, in engineering, not only the working point of the system, should be set in the sub-resonant region with respect to the natural frequency of the main vibrating system in x- and y- directions, but also the distance between the rotational center of each vibrator and the centroid of the system, must be adjusted to be larger to meet the above requirements. Only in this way, can the greater relative vibration amplitude of the system characterized by the circular motion be realized, the energy be saved, and the ideal isolation effect be satisfied.
Sustainable production of toxin free marine microalgae biomass as fish feed in large scale open system in the Qatari desert.
Mass cultivation of microalgae biomass for feed should be cost effective and toxin free. Evaporation loss in Qatar can be as high as 2 cm/d. Hence, production of marine microalgae biomass in Qatar would also require mitigating water loss as there was only very limited groundwater reserve. To address these issues, a combination of four growth conditions were applied to a 25,000 L raceway pond: locally isolated microalgae strain was selected which could grow in elevated salinity; strain that did not require silica and vitamins; volume of the culture would increase over time keeping denser inoculum in the beginning, and evaporation water loss would be balanced by adding seawater only. A local saline tolerant Nannochloropsis sp. was selected which did not require silica and vitamins. When the above conditions were combined in the pond, average areal biomass productivities reached 20.37 g/m(2)/d, and the culture was not contaminated by any toxic microalgae.