Design of cellular manufacturing systems with refixturing considerations.

The objective of this research is to deal with some specific production planning and design problems during cell formation. Important manufacturing realities such as refixturing and material handling during operation allocation and cell formation were considered. Model 1 and model 2 consider the problem of assigning operation(s) of part types to one or more machines in a cellular manufacturing environment. Model 1 is developed for the case of a single cell and model 2 extends the operation allocation problem for multiple cells. Model 3 and model 4 are developed to determine machine groups and assignment of part operations to machines. Model 3 is used to simultaneously assign operations of parts to machines and form machine groups. Model 4 is developed for the situation where new machines are procured for the cellular manufacturing environment. Considerations of physical limitations such as an upper bound on cell size, machine capacity, etc., were also incorporated into cell formation and presented. These models bring forth the trade-offs between refixturing, inter cell movement and investment costs. A few illustrative examples were solved using the package LINDO (PC version) and the results were analyzed. (Abstract shortened by UMI.)Dept. of Industrial and Manufacturing Systems Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1991 .D356. Source: Masters Abstracts International, Volume: 30-04, page: 1450. Thesis (M.A.Sc.)--University of Windsor (Canada), 1990

Numerical simulation of flow through pipes with multiple constrictions and with moving walls.

A numerical method has been developed to solve steady laminar flow through a tube with multiple constrictions and pulsatile flow through tubes with moving boundaries. The governing equations were formulated in body fitted curvilinear coordinates so that arbitrary domains and moving boundaries could be handled. A finite volume discretization procedure was used to solve the governing equations. Four practical flow problems were numerically simulated in this work. In the first case, tubes with one, two, three, four and seven constrictions were considered. For the second case, the flow through a tube with multiple constrictions was solved by considering a single module where the flow field was assumed to be periodic. By comparing the results of these two cases, the effects of the number of constrictions on wall shear stress, pressure drop, vorticity, streamlines and velocity distributions as the flow passed through the tube were studied and the development of periodicity characteristics was investigated. The computations were carried out for a range of Reynolds numbers between 50 and 250. The third case studied had a pulsatile flow at the inlet of a tube having a constriction which changed in shape periodically with time at a prescribed frequency. The fourth case also had a pulsatile flow at the inlet with a portion of the wall that changes shape periodically with time. In this case, however, the variation caused contraction of the pipe at one portion of the cycle and distention at another portion alternatively. The presence of moving boundaries in the above mentioned cases caused additional unsteadiness to occur in the flow. This unsteady behaviour in the flow was investigated over a range of frequencies.Dept. of Mechanical, Automotive, and Materials Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1995 .D35. Source: Dissertation Abstracts International, Volume: 57-07, Section: B, page: 4651. Advisers: G. W. Rankin; C. Zhang. Thesis (Ph.D.)--University of Windsor (Canada), 1996

Recent Advances in MEMS-Based 3D Hemispherical Resonator Gyroscope (HRG)—A Sensor of Choice

Macro-scale, hemispherical-shaped resonating gyroscopes are used in high-precision motion and navigation applications. In these gyroscopes, a 3D wine-glass, hemispherical-shaped resonating structure is used as the main sensing element. Motivated by the success of macroscale hemispherical shape gyroscopes, many microscale hemispherical-shaped resonators have been produced due to the rapid advancement in semiconductor-based microfabrication technologies. The dynamic performance of hemispherical resonators depends on the degree of symmetry, uniformity of thickness, and surface smoothness, which, in turn, depend on the type of materials and fabrication methods. The main aim of this review paper is to summarize the materials, characterization and fabrication methods reported in the literature for the fabrication of microscale hemispherical resonator gyroscopes (µHRGs). The theory behind the development of HRGs is described and advancements in the fabrication of microscale HRGs through various semiconductor-based fabrication techniques are outlined. The integration of electrodes with the hemispherical structure for electrical transduction using other materials and fabrication methods is also presented. A comparison of different materials and methods of fabrication from the point of view of device characteristics and dynamic performance is discussed. This review can help researchers in their future research and engineers to select the materials and methods for µHRG development