Papers by Keyword: Rotation

Abstract: The in vivo measurement of the cartilage contact area (CCA) during shoulder rotation remains unexplored. This study, therefore, investigates changes in the CCA and cartilage contact pattern (CCP) between the humeral head and glenoid during static rotation with abduction using magnetic resonance imaging (MRI) in subjects with normal shoulders. The study subjects were 14 Japanese men without a previous history of shoulder injury or disorder. MRI data were obtained from the transverse sections of the shoulder using a 3T-MRI scanner in the following four postures: neutral posture, posture at neutral rotation with 120° of abduction (AB posture), posture at 100° of external rotation with 120° of abduction (ER posture), and posture at 30° of internal rotation with 120° of abduction (IR posture). The CCA and CCP (contact centroid) of the glenohumeral joint were determined from the MRI data. The CCA in the AB posture was significantly smaller than that in the neutral posture (p = 0.015). The CCAs in the ER and IR postures were approximately 23.1% and 35.2% larger, respectively, than that in the AB posture. The contact centroid at the AB posture was located significantly more superior to those at the neutral, ER, and IR postures (p < 0.001, p = 0.012, p < 0.001, respectively). Results offer new insights into the CCA and CCP of the glenohumeral joint during in vivo shoulder rotation. This study provides a useful reference dataset obtained from young participants with normal shoulders for understanding cartilage contact mechanics. Improved understanding of the contact pattern can help detect shoulder joint disorders and develop subsequent treatment and surgical strategies.

Abstract: Even though the descriptive definition of orientation is the same in both settings, the explicitnotation of a crystallographic orientation as (3 3) matrix in terms of Euler angles featuredby the popular MATLAB toolbox MTEX differs by an inversion from the quasi-standard notation datedback to the early days of quantitative texture analysis championed by H.-J. Bunge. The origin of thisdiscrepancy is revealed by an enlightening view provided in algebraic terms of a change of basis.Understanding the effect of inversion is instrumental to do proper computations with crystallographicorientations and rotations, e.g. when multiplying with elements of a crystallographic symmetry group,and to compare results of texture analyses accomplished in different settings.

Abstract: In the present research study a mathematical analysis has been presented for unsteady MHD natural convective flow of a rotating fluid over an infinite vertical plate immersed in a fluid saturated porous medium with oscillating free-stream. The effects of Hall and ion-slip currents also considered on the fluid flow. The unsteady MHD flow over the vertical plate is induced due to thermal and concentration buoyancy forces and oscillatory movement of the free-stream. The partial differential equations governing the motion for the fluid flow are solved analytically. The effects of various pertinent flow parameters on the fluid velocity, fluid temperature and species concentration are presented in graphical form whereas that on skin friction and rate of heat and mass transfer at the plate are presented in tabular form. An interesting observation recorded from the present analysis that there appears reversal flow in the secondary flow direction due to presence of thermal and/or concentration buoyancy forces. However, in the absence of both reversals flow does not exist in the secondary flow direction. It is also noted that the thickness of momentum boundary layer decreases with rise in frequency of oscillations of the free-stream.

Abstract: The demand and usage of vegetable oil utilization in lubricants for many applications increased prompting by continued growing environmental concerns. Today, vegetable oil attracts attention as biodegradable alternates for synthetic esters because they are cheaper and can be obtained from sources that are renewable. The main objectives of this experiment were to measure the friction force at various speeds and to observe the surface roughness before and after experiment. In this experiment, RBD palm olein as represented vegetable oil has been tested by compare the result with fully synthetic oil and mineral-based oil by using modified pin-on-disc machine. Pure RBD palm olein, recorded only 7.4% of increment of maximum friction force compared to results for mineral-based oil. Observation based on surface roughness show that RBD palm olein works as effective as fully synthetic and mineral-based oil since only 14.6% increment of overall surface roughness for the whole shaft. Therefore, the performance of vegetable oil which in this experiment is RBD palm olein, can be improve by adding additive so increase it properties such as can withstand at high load, high flash point parameter, small wear scar diameter, less oxidation rate, and coefficient of friction.

Abstract: The objective of this project is to design a center pivot irrigation system and determine the efficiency of the system by using experimental method by build a model of the system. For that, a literature study is carried out to understand the theories of center pivot irrigation system. Center pivot irrigation system is the system that can rotate 360 degree around the center pivot. Before model build, the theoretical calculation need to be done to calculate the specification of the model. The model of the experiment purpose build not included the rotation part because the rotation part not gives an effect to the water flow. The experiment procedure follows the standard of North Carolina State University that conducts this type of experiment. From the experiment, the uniformly efficiency of the irrigation system can be defined. Scaled model use in this experiment to determine the uniformly efficiency by using specification from the theoretical calculation. From the previous experiment the uniformly efficiency of the irrigation system is 50% - 60% and the uniformly efficiency of center pivot irrigation system is about 75% - 90%.

Abstract: A mathematical model has been proposed for analyzing the momentum, heat and mass transfer in Bio-convection flow towards a rotating cone/plate in a rotating fluid with nonlinear thermal radiation and chemical reaction. In this study we considered gyrotactic microorganism’s contained Williamson fluid. Numerical results are carried out by using Runge-Kutta based shooting technique. The effects of dimensionless governing parameters on the flow, heat and mass transfer are illustrated graphically. It is also computed the friction factors for the tangential and azimuthal directions, local Nusselt and Sherwood numbers along with the local density of the motile organisms. It has been observed a good agreement of the present results with the existed literature. The obtained results indicate that the heat and mass transfer rate is significantly increases for higher values of buoyancy parameter and Biot number. It is also found that the heat and mass transfer performance in Bio-convection flow is significantly high on the flow over a rotating plate while compared with the rotating cone.

Abstract: In this study we investigated the effect of nonlinear thermal radiation on magnetohydrodynamic flow between horizontal rotating plates in the presence of homogeneous-heterogeneous reactions. By making use of the appropriate similarity transformations, the equations which govern the flow are reduced to a set of nonlinear ordinary differential equations. Further, these equations are solved numerically using the Runge-Kutta based shooting technique. Also, the effects of various pertinent parameters on velocity, temperature and concentration profiles along with the friction factor, local Nusselt and Sherwood numbers are discussed and presented with the help of graphs and tables. We found an excellent agreement of the present results with the existed literature under some special limited cases. Results indicate that concentration profiles are highly influenced by the homogeneous-heterogeneous parameters. Nonlinear thermal radiation have tendency to enhance the thermal boundary layer thickness.

Abstract: The efficiency of the technological operations executed by robots depends on how their kinematic parameters were calculated. This paper presents the exactly calculus of the robots kinematics parameters. As the algorithm has a substantial number of operations, it is necessary to use the computer.

Abstract: SiC_f/SiC composites are one of the candidates for high temperature structural applications because of their high strength and corrosion resistance under severe conditions and stability under neutron irradiation [1~3]. A silicon carbide fuel cladding for the light water cooled reactors (LWRs) may allow a number of advances, including: the increased safety margins under transients and accident scenarios, such as loss of coolant accident; the improved resource utilization via a higher burn-up beyond the present limit of 62 GWd/MTU; and improved waste management [3~5]. Some components of SiC_f/SiC composite will be applied as tubular geometry for the high-temperature core parts. The proposed design of an advanced LWR fuel cladding, referred to as Triplex, consists of three layers: an inner SiC monolith, a central SiC_f/SiC composite, and an outer dense SiC evrionmental barrier coating. The inner SiC layer provides the strength and hermeticity to contain fission products. The SiC_f/SiC composite layer fabricated by the CVI process provides a pseudo-ductile failure mode. The outer SiC thin coating layer protects against corrosion [5]. The chemical vapor deposition (CVD) technique is an effective approach for the fabrication of SiC_f/SiC composite and coated SiC monolith [6]. To increase the homogeneity of the microstructure and the deposition rate of a SiC tube, the process parameters should be optimized and modified.

Abstract: In order to adapt to the needs of internal combustion engine speed variation of the turbocharger. Using waste gas regulator control exhaust gas inlet device. The effect of exhaust gas regulator is for adjusting the gas flow velocity and direction. When the internal combustion engine running at low speed raising the impeller speed. Exhaust gas regulator and axial moving blades rotating blades of two kinds of structure. The axial moving blade structure is changing the way nozzle ring opening work. Rotating blade structure is working on changing the way of blade Angle. Exhaust gas to adjust the turbocharger is a control of internal combustion engine air pressurization value of the speed changes.