Report (M.S.)--Virginia Polytechnic Institute and State University. M.S. 1991. / Vita. Abstract. Includes bibliographical references (leaf 105). Also available via the Internet.

Thesis (M. Sc.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 90-96).

International Telemetering Conference Proceedings / October 30-November 02, 1989 / Town & Country Hotel & Convention Center, San Diego, California / The need for ever-increasing miniaturization of airborne instrumentation through the use of surface mounted components closely placed on printed circuit boards highlights problems with traditional board cleaning methods. The reliability of assemblies which have been cleaned with vapor degreasing and spray cleaning can be seriously compromised by residual contaminants leading to solder joint failure, board corrosion, and even electrical failure of the mounted parts. In addition, recent government actions to eliminate fully halogenated chlorofluorocarbons (CFC) and chlorinated hydrocarbons from the industrial environment require the development of new cleaning materials and techniques. This paper will discuss alternative cleaning materials and techniques and results that can be expected with them. Particular emphasis will be placed on problems related to surface-mounted parts. These new techniques may lead to improved circuit reliability and, at the same time, be less expensive and less environmentally hazardous than the traditional systems.

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This dissertation addresses the "multi-machine carryover sequence dependent group-scheduling problem with anticipatory setups," which arises in the printed circuit board (PCB) manufacturing. Typically, in PCB manufacturing different board types requiring similar components are grouped together to reduce setup times and increase throughput. The challenge is to determine the sequence of board groups as well as the sequence of individual board types within each group. The two separate objectives considered are minimizing the makespan and minimizing the mean flow time. In order to quickly solve the problem with each of the two objectives, highly effective metasearch heuristic algorithms based on the concept known as tabu search are developed. Advanced features of tabu search, such as the long-term memory function in order to intensify/diversify the search and variable tabu-list sizes, are utilized in the proposed heuristics. In the absence of knowing the actual optimal solutions, another important challenge is to assess the quality of the solutions identified by the proposed metaheuristics. For that purpose, methods that identify strong lower bounds both on the optimal makespan and the optimal mean flow time are proposed. The quality of a heuristic solution is then quantified as its percentage deviation from the lower bound. Based on the minimum possible setup times, this dissertation develops a lower bounding procedure, called procedure Minsetup, that is capable of identifying tight lower bounds. Even tighter lower bounds are identified using a mathematical programming decomposition approach. Novel mathematical programming formulations are developed and a branch-and-price (B&P) algorithm is proposed and implemented. A Dantzig-Wolfe reformulation of the problem that enables applying a column generation algorithm to solve the linear programming relaxation of the master problem is presented. Single-machine subproblems are designed to identify new columns if and when necessary. To enhance the efficiency of the algorithm, approximation algorithms are developed to solve the subproblems. Effective branching rules partition the solution space of the problem at a node where the solution is fractional. In order to alleviate the slow convergence of the column generation process at each node, a stabilizing technique is developed. Finally, several implementation issues such as constructing a feasible initial master problem, column management, and search strategy, are addressed. The results of a carefully designed computational experiment for both low-mix high-volume and high-mix low-volume production environments confirm the high performance of tabu search algorithms in identifying extremely good quality solutions with respect to the proposed lower bounds. / Graduation date: 2006

Stress constitutes a more and more common cause for many health disorders inmodern society. Salivary -amylase (AA), the most abundant enzyme in humanwhole saliva, has in recent years been found to be a good surrogate biomarker formonitoring stress levels in individuals. This work aims to form the foundation ofa novel approach for measuring the activity of the enzyme in saliva samples bymeans of electrochemistry. The idea is to implement several enzymes along witha starch substrate and an electron mediator in a single system. This system isthen to be coated onto a screen-printed electrode (SPE), which is used along withan electrical component, designed to give rise to a quantifiable, electrical signalwhen the starch is broken down by the AA contained in an added saliva sample.Several such enzyme systems are here qualitatively evaluated. As electron mediator,ferro-/ferricyanide is used. Two different enzymes, glucose oxidase (GOx) andpyrroloquinoline quinone dependent glucose dehydrogenase (PQQ-GDH), are testedfor making up the saccharide oxidising part of the system. Both prove themselvescapable in terms of qualitatively giving rise to an electrical signal. But, in terms ofinternal quantitative comparisons between the two, no practical experiments areperformed in this work. In some runs, the enzyme -glucosidase (AG) is used asan intermediate for breaking down the AA/starch oligosaccharide products intomonosaccharides. This to increase the system’s electrical signal output when usingGOx as oxidising agent. Regrettably, due to lack of AG enzyme, these runs do notprovide any conclusive data, and so further investigations of systems including thisenzyme are needed. Otherwise, all systems tested seem to work, and neither ofthem appear better than the others. Therefore, all of them will require furtherquantitative testing to determine which one is best to implement in the final designof the enzyme system to be applied onto the SPE.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: welding; ultrasonic. Includes bibliographical references (p. 100-101).