No description available.

Thesis (Ph. D.)--Columbia University, 1929. / Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: p. 68.

The physical quantity of the square of tensile strength over Young’s modulus has been proposed as a criterion of comminution of rock by Oka and Majima. The value was determined for five different rocks, measuring tensile strength and Young's modulus. The testing method used to determine both rock properties was a point-load tensile strength test and measurement of propagation velocity of P-wave. In order to verify the applicability of the criterion thus obtained, the drop-weight impact test and ball mill grinding were carried out using the identical specimen used for tensile strength and Young's modulus test. The experimental result was obtained that the square of tensile strength is more applicable than the square of tensile strength over Young's modulus. In chapter 2, grinding tests were performed with a 12 inch batch mill. A torque meter was installed to estimate the energy consumption.necessary to achieve size reduction. From the torque measurement, the required torque for the mill turning remained almost constant regardless of the material being ground. A new concept, Energy Index, was introduced to evaluate grinding results and to study grinding problems. For each rock sample tested, the energy index was determined from torque measurements and the quantity of the products. It was found the energy index has a linear relationship with Bond work index under selected grinding condition. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate

This thesis is aimed to apply cylindrical polishing system to a large flat workpiece (ex:wafer) to obtain high degree of planarization, low surface roughness and no crack layer. First, a mathematical model is presented which describes the axially symmetric form error compensation by cylindrical polishing process. The dwelling time-distribution of tool and the machining depth distribution are solved using the methods of simultaneous equations and least square error with non-negativity constraints. Then, using the simulation analysis and experimental method to examine the machining rate distribution effects on machining precision and the dwelling time-distribution of the tool when the workpiece is machining by cylindrical tool. The examined effects will include machining length effect, boundary effect and inclined effect. Under the range of the machining precision required, the approach to smooth the dwelling time-distribution of tool that will benefit layer-by-layer removing strategy. After these analyses, an adequacy dwelling time-distribution of the tool can be designed according to the workpiece form error. In addition, the relative between the machining probability due to the an-isotropic polishing property and surface roughness will be discussed. The contents of this thesis include three parts. First, a mathematical model is presented which describes the axially symmetric form error compensation by cylindrical polishing process. And, the polishing angles and polishing probability of the an-isotropic polishing property will be identified according to the mathematical model. Second, the design of dwelling time-distribution of tool and the analysis of the geometric effects will be discussed by computer simulation. Third, the experimental results will show the suitable of the machining strategy and compare the machining effects with the simulated results. And, the planarization of the workpiece that has axially symmetric form error will be done.

No description available.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2008. / Includes bibliographical references.

QC 351 A7 no. 71 / Generalized ray tracing is a method of calculating the principal curvatures and directions of the wavefront associated with a ray as it is traced through an optical system. The results of such a ray trace provide important information about the structure of the image and have immediate application to lens design and image analysis. The caustic surface formed by an optical system can be easily determined from the results of a generalized ray trace. An examination of several caustic surfaces formed by different optical systems provides valuable information about the relative quality of the images and indicates some of the advantages of the generalized ray tracing method.

Call number: LD2668 .T4 1951 M377 / Master of Science

Call number: LD2668 .T4 1951 W3 / Master of Science

A process planning strategy was proposed to suppress the wear effect of tool in a polishing of axially symmetrical work. This strategy can keep machining rate of tool to be constant. In study, we need to design the proper dwelling time distribution for tool to remove error of axially symmetrical surface and use computer to simulate. Observe the residual error on surface of work. Analyze the outcome of experiment and estimate feasibility of the strategy. According to the way of motion of tool, it could cause two difficulties: 1.To design the dwelling time distribution of tool will be more difficult. 2.The load of tool will be unstable. In order to solve this first difficulty, in a new strategy of working, the dwelling time distribution of tool must be a multiple of integral of the period of work rotation. And experiment to prove it, analyze and discuss the outcome of experiment. Second problem cause the load of tool to be unstable in experiment. To improve the load of tool, a new strategy was proposed to control load and to verify effectiveness for the strategy. Finally, analysis and discuss the outcome of experiment, and estimate the practicability of the strategy.