Thesis (M.S.) in Resource Economics and Policy--University of Maine, 2002. / Includes vita. Includes bibliographical references (leaves 63-67).

All machined surfaces inherently have roughness. The level of control of this surface is dependeat on the specifications outlined for its intended use. In strictly controlled situatiom, the monitoring and characterization of these surfaces becomes increasingly important to ensure that each component conforms to specifications. For this reason, the need for in-situ monitoring systems has increased in order to optimize manufacturing time and minimize generated scrap for companies to remain competitive in industry. Current in-situ roughness monitoring systems, such as optical methods, are limited by the harsl: environments in which these systems are required to operate and the requirement for highly reflective materials. Accordingly, the need to develop a more robust system is required. The objective of this work was to develop and test a noncontact surface roughness characterization system which can be implemented into a machining center in order to provide in-situ measurements where currently available methods are rendered inappropriate. Through the use of a pneumatic technique, a non-contact surface assessment tool has been developed and tested for use in a machining center. The development began offline for characterization of surfaces created by different machining operations and was then introduced in to a turning center for in-situ evaluation. The developed system is capable of distinguishing surfaces created from different machining operations with the same Ra values, characterize milled and turned surfaces down to R^a values of 0.8 μm that are comparable with stylus measurements, impervious to external influences on the measurement process such as cutting fluid, capable of characterizing moving surfaces with surface speeds up to 100 m/min, provides surface characterization around the entire workpiece instead of along a single line, and can be operated in-process to monitor the entire workpiece or be used to make spot checks for important surface features. The developed system is capable of providing a method for in-situ monitoring of machined surfaces where currently available techniques fall short. The limitations caused by the harsh environment in which these in-situ monitoring devices operate and the limitations of workpiece materials have been eliminated and the developed system has been proven to provide results comparable to stylus measurements that are the industrial standard. This work is the basis for the development of a non-contact, in-situ surface roughness assessment tool. Limitations of the current device are also presented. Further research and development avenues are identified to expand the operating envelope of the developed pneumatic system. / Thesis / Master of Applied Science (MASc)

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In most mine clearing or earth moving equipment such as bulldozers, the working tool is a blade. The blade geometry and operating conditions, such as cutting speed, cutting angle, and cutting depth, have a great effect on overall machine productivity. Most of the published experimental studies confirm these effects. However experimental studies are expensive and their results are highly dependant on the accuracy of measurement devices and the reliability of experimental procedures employed. Numerical techniques have recently shown more promise especially with the current increase in computational power and development of more sophisticated material models. However in order to simulate the soil-tool interface process accurately, careful selection of the appropriate material model for the soil and the interface is required. This should, ideally, be based on a reasonable number of material parameters that have direct physical meaning. In this study a review of the available constitu tive models for soil (particularly sand) and soil-tool interface was carried out. This review study concluded by selecting the so called hypoplastic model as the most appropriate to simulate the sandy soil behavior over a wide range of stresses. Some modifications were carried out on this selected hypoplastic model to optimize it for simulation of the soil-tool interaction process, which is characterized by monotonic loading and high deformation. The modified model was verified numerically and then implemented into the finite element method via an ABAQUS user defined subroutine UMAT. Then the implemented model was verified through analysis of some benchmark problems and results were compared with results from different classical failure criteria. The finite element analysis revealed the high performance of the hypoplastic model in simulating sand behaviour. Finally an analysis of various factors affecting soil-tool interaction was carried out in both two-dimensions and three-dimensions. Results revealed the significant effect of both geometry and operating conditions on blade cutting forces and confirmed the ability of the finite element method to analyze the soil-tool interaction process.

The quest of this project is to question and better understand the effects of a widening gap between Middle East and West on Middle Easterners’ experiences and feelings in exile, inbetween. This is to articulate this separation, but also to invent a visual and spatial experience that may enable us to traverse the space of the border. For those not in and of this space, as well as for those in it, a new way of looking may furnish a better understanding of both positions and facilitate communication.

The quest of this project is to question and better understand the effects of a widening gap between Middle East and West on Middle Easterners’ experiences and feelings in exile, inbetween. This is to articulate this separation, but also to invent a visual and spatial experience that may enable us to traverse the space of the border. For those not in and of this space, as well as for those in it, a new way of looking may furnish a better understanding of both positions and facilitate communication.

A mathematical model of a discrete sequential search for a target moving in discrete space is given. The model is based on a Bayesian updating algorithm giving successive probability distributions of target position at intervals throughout the search. Updating allows for target movement and for negative information gained from unsuccessful search. The search is conducted by taking a sequence of discrete, instantaneous looks at chosen points, or nodes, of the search area. The sequence of chosen nodes is termed a strategy. The successive target position distributions allow the probability of detecting the target to be found for any strategy. The model is an improvement over previous discrete sequential search models with respect to the following points. Target movement between nodes of the search area is formulated in terms of statistical information of target speed and direction, which are likely to be known. The time interval between looks, and target movement during this time, are related to the distance travelled by the searcher between search nodes. Also, with each look, the searcher has a view of surrounding nodes as well as the chosen search node. Implementation of these refinements is aided by considering the search area to consist of a finite, isometric pattern of nodes. Optimisation of strategies with respect to both detection probability and detection probability per unit cost is considered, and a criterion given in each case to assist optimisation. However, in practice, these criteria are of limited use, and full optimisation can only be carried out in a limited range of cases. Restricting both the planning horizon of the optimisation process, and searcher travel distance, allows sub-optimal strategies to be found in a wider range of cases. Results suggest that the detection probability of strategies found under these restrictions is normally close to optimal.

Thesis--Boston University. / Forced moving is a problem in social change. Reanalyzing survey data from interviews with 102 Boston households who made a forced move between 1968 and 1970, a theoretical model is developed which explains the type and variety of these changes. The household, the residents of one dwelling unit, is the unit or system affected by a forced move. All social systems must solve the four Parsonian functions to continue to exist. Households differ in the adequacy of their solutions. In the model the independent variables are the household's levels of functioning before the forced move and the dependent variables are the housing and attitudinal changes accompanying a forced move. Two hypotheses specified the relationship between the changes accompanying a forced move and influences on these changes. Hypothesis I stated that households with positive functioning before the forced move would report positive changes after the forced move. In the model all four household functions do not contribute equally to forced move outcomes. Assuming that rehousing after a ... [TRUNCATED]

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