Parameter study of chain trenching machines of Underwater Construction Robots via analytical model
Analytical model by considering the kinematics, dynamics, and energetics of the trenching machine is adopted and proposed to design an underwater chain trenching machine at UCRC-KIOST. In this paper, parameter study and sensitivity analysis is conducted to show how the variations of operational and geometric parameters, as well as cutting tools and material condition affect the forces, moment, weight, and power components. The study sheds some important insights about how the trenching machine behaves and thus the information from this study can be used to design a trenching machine for the required working condition. The parameter study shows that minimum weight requirement for self-propelled vehicle is increased during operation at steep bar angle, and to keep the traction of the vehicle getting worst, it is recommended to cut the trench at low bar angle and make sure the cutting tool is still sharp. The results also show that traverse speed, cutting depth, uniaxial compressive strength, and trench width are the most sensitive parameters affecting the power and angular speed. On the other hand, weight of the vehicle, nose radius, bar length, and pivot point location does not affect the total chain power at all.
Mechanics of Cutting and Boring. Part 1: Kinematics of Transverse Rotation Machines.
Abstract : This report, which is one of a series on the mechanics of cutting and boring in rock, deals with the kinematics of machines such as disc saws, drum millers, rotary planers and bucket-wheel excavators, in which the rotary cutting element revolves about an axis that is normal to the direction of working travel. The analysis covers the geometry and motion of various components of the cutting system, touching on topics such as chipping depth, cutting transfer, excavation rate, tool trajectories, tool speeds, rake and relief angles on tools and tool layout. Worked examples are given to illustrate various points.
Development of an Analytical Method for Explosive Residues in Soil
Abstract : An analytical method was developed to determine the concentrations of HMX, RDX, TNB, DNB, Tetryl, TNT and 2,4-DNT in soil. The method involves extracting a 2-g sample with 50 mL of acetonitrile using an ultrasonic bath procedure for 18 hr. A 10-mL portion of the extract is diluted with 10 mL of water, filtered through a 0.45-micrometer Millex SR filter, and analyzed by RP-HPLC using a fixed 254-nm UV detector. Separations were obtained on an LC-18 column eluted with 50:50 water-methanol. Retention times were 2.55, 3.82, 5.16, 6.25, 7.04, 8.47 and 10.15 min for HMX, RDX, TNB, DNB, Tetryl, TNT and 2,4-DNT, respectively. Confirmation of analyte identities is recommended by RP-HPLC on an LC-CN column using 50:50 water-methanol. Kinetic studies using naturally contaminated soil indicated that equilibrium was achieved within 24 hr for the majority of soils and analytes studied. The method provides linear calibration curves over a wide range of concentrations. Reporting limits were conservatively estimated at 1.6, 1.8, 1.5, 0.5, 5.5, 0.8 and 0.8 micro grams/g for HMX, RDX, TNB, DNB, Tetryl, TNT and 2,4-DNT. Analytical precision was estimated at + or - 0.44, 0.51, 0.43, 0.13, 1.24, 0.27 and 0.20 micro grams/g, respectively, in the range of homogeneous variance near the detection limits. At higher concentrations the relative standard deviation was constant at 2% for HMX, RDX, DNB and TNB, 3% for TNT and 2,4-DNT, and 6% for Tetryl.