-
Particle Focusing in Microchannel with Multi-Parallel Channels or Porous Orifice
Hiroshige Kumamaru,
Hirofumi Sugami,
Masaki Nakahira,
Naohisa Takagaki
Issue:
Volume 6, Issue 3, June 2018
Pages:
46-54
Received:
22 April 2018
Accepted:
7 May 2018
Published:
28 May 2018
Abstract: The sheathless particle focusing in a microchannel installing one set of multi-parallel channels or one porous orifice is proposed in this study. Numerical calculations have been carried out by the Lagrange two-phase model (i.e. the particle tracking model) in PHOENICS software for the microchannel including the porous orifice, in simulating both the channels installing the multi-parallel channels and the porous orifice. It becomes clear from calculation results that the particle focusing may be achieved at lower inlet velocities by using the porous orifice. Low velocities correspond to reduction in the sample flow including particles (i.e. cells). It also becomes obvious that the particle focusing is improved if the porous orifice with taper shape is used. Furthermore, particle focusing experiments have been conducted in the channel including the multi-parallel channels. It becomes clear that the particle focusing may be achieved by using the multi-parallel channels.
Abstract: The sheathless particle focusing in a microchannel installing one set of multi-parallel channels or one porous orifice is proposed in this study. Numerical calculations have been carried out by the Lagrange two-phase model (i.e. the particle tracking model) in PHOENICS software for the microchannel including the porous orifice, in simulating both t...
Show More
-
Modification and Manufacturing of Cereal Crop Harvesting Machine
Issue:
Volume 6, Issue 3, June 2018
Pages:
55-58
Received:
19 April 2018
Accepted:
16 May 2018
Published:
11 June 2018
Abstract: Today the development of agricultural sector is increasing from year to year. The rice, wheat and other cereals are the focus of many farmers in Ethiopia. But to harvest on time the cereals, intensive human power is needed. Most of the time students starting from elementary level up to university level participate on harvesting of cereals due to unbalance rainfall. To solve this problem, harvesting machines are very essential. Harvesting machinery or equipment is a mechanical device used for harvesting different types of crops. The use of modern tractors, combine harvesters and related heavy machineries is still very limited in Ethiopia. On the other hand, a rising trend in the import of tractors and harvesters is being observed as of recent years. Small-scale farmers on their part are looking more into the use of small mechanically-powered equipment both for crop production and post-harvest activities. From the available machines in the world, different cereal crop harvesting machines were assessed. Using different selecting criteria mower is selected. The design and economic analysis is performed for the selected harvesting machine. Different parts of the machine are designed including material selection and different force analysis like bending, shear stress. Finally parts and assembly drawings are drawn and the prototype is manufactured from the available materials.
Abstract: Today the development of agricultural sector is increasing from year to year. The rice, wheat and other cereals are the focus of many farmers in Ethiopia. But to harvest on time the cereals, intensive human power is needed. Most of the time students starting from elementary level up to university level participate on harvesting of cereals due to un...
Show More
-
Research and Development of Economical CNC Software for 2D Lean Friction Stir Welding Machine
Diop Sokhna Anta Balla,
Zhou Hu,
Xu Chi
Issue:
Volume 6, Issue 3, June 2018
Pages:
59-63
Received:
19 June 2018
Published:
20 June 2018
Abstract: This project is developing a two-dimensional friction stir machine, relatively low cost to achieve four axis friction stir welding equipment with real-time servo control, where the corresponding trajectory planning function in cam is relatively independent by making a full use of Galil motion controller has a strong multi axis linkage control capability and fast real-time communication capabilities and the Galil motion controllet G code analysis software module is developped. This paper is studying the trajectory planning software system design and development of friction stir for different trajectories in the plan and is aiming to solve the motion trajectory control problem with complex welding path. A deep study of three polynomial spline function trajectory planner is done, and the complex motion trajectory of the multi axis welding machine controlled by acceleration and speed is realized. The micro arc transition approximation method is applied to optimize the inflection point with abrupt change of track path and achieve smooth inflection motion.
Abstract: This project is developing a two-dimensional friction stir machine, relatively low cost to achieve four axis friction stir welding equipment with real-time servo control, where the corresponding trajectory planning function in cam is relatively independent by making a full use of Galil motion controller has a strong multi axis linkage control capab...
Show More
-
Analytical Solution of Stiffness for a Corner-Fillet Leaf-Spring Type Flexure Hinge with a Long Fatigue Life
Li Rui-qi,
Wu Bai-sheng,
Chen Xin,
Yang Zhi-jun
Issue:
Volume 6, Issue 3, June 2018
Pages:
64-72
Received:
17 May 2018
Accepted:
5 June 2018
Published:
29 June 2018
Abstract: Flexure hinges as the displacement guiding and amplifying mechanism or sensing component are widely used for micro-actuators and sensors. However, the existing flexure hinges, leaf-spring or notch type, cause serious stress concentration which severely weaken the fatigue life of compliance mechanism. Therefore, developing long fatigue life flexure hinges is very important for high working frequency actuators and sensors, such as fast-tool-servo. Corner-fillet leaf-spring type flexure hinge could provide large displacement with lower stress. Stiffness expressions of it with both fixed-fixed and fixed-guided boundary conditions are derived by using Castigliano’s theorem. The main influence factors for stress concentration are investigated and the formulas of stress concentration factor are obtained in terms of ratio of fillet radius to the minimum thickness. These analytical formulas have been verified by comparing with finite element analysis (FEA) results. Stress-life method is chosen to research the influence of fillet radius on fatigue life and the results indicate fillet radius can improve fatigue life of flexure hinge effectively. The proposed analytical solution is the fundamental of optimal design of a leaf-spring type flexure hinge based mechanism with fatigue life constraints.
Abstract: Flexure hinges as the displacement guiding and amplifying mechanism or sensing component are widely used for micro-actuators and sensors. However, the existing flexure hinges, leaf-spring or notch type, cause serious stress concentration which severely weaken the fatigue life of compliance mechanism. Therefore, developing long fatigue life flexure ...
Show More
-
The Effect of the Fluid Film Variable Viscosity on the Hydrostatic Thrust Spherical Bearing Performance in the Presence of Centripetal Inertia and Surface Roughness Part 2, Recessed Fitted Bearing
Ahmad Waguih Yacout Elescandarany
Issue:
Volume 6, Issue 3, June 2018
Pages:
73-90
Received:
12 July 2018
Accepted:
14 August 2018
Published:
11 September 2018
Abstract: The study deals with the fluid viscosity variation, the centripetal inertia and the bearing surface roughness affecting the externally pressurized thrust spherical bearing performance where the partial differential equation of the temperature gradient previously derived from the fluid governing equations, is integrated and applied to this type of bearings to calculate and predict temperature distribution along the fluid film. In this part of the research, the recessed fitted type of bearings has been studied deriving mathematical expressions that not only cover this configuration but also cover the fitted type of this bearing with its different configurations and showing also the recess effect on the bearing performance. The results showed the effect of the viscosity variation on the pressure, the load caring capacity, the fluid flow rate, the frictional torque, the friction factor, the power factor, the stiffness factor and the central pressure ratio as well as the effect of the speed parameter and the eccentricity on the temperature rise. Applying these derived mathematical expressions, which could be considered as a general solution for the fitted type, an optimum design for the fitted type with its different configurations (with and without recess; hemispherical and partial hemispherical seats) has been performed. Using the same bearing dimensions, the application of these equations proved the excellence of the aforementioned optimum design of this bearing in our previous papers where the temperature of the outlet flow was less than 14 degrees centigrade over its inlet temperature.
Abstract: The study deals with the fluid viscosity variation, the centripetal inertia and the bearing surface roughness affecting the externally pressurized thrust spherical bearing performance where the partial differential equation of the temperature gradient previously derived from the fluid governing equations, is integrated and applied to this type of b...
Show More
