This thesis demonstrates the feasibility of methods developed to increase the quality of the crescent bond together with the tail bond quality. Low pull force of the crescent bond limits the usage of insulated Au wire in microelectronics assembly. Premature break of the tail which results in the stoppage of the bonding machine is one of obstacles to overcome for Cu wire. The primary focus of this thesis is to understand the tail and crescent bonding process and then to propose methodologies to improve thermosonic wire bonding processes when Cu and insulated Au wires are used. Several series of experiments to investigate the crescent and tail bonding processes are performed on auto bonders. Cu and insulated Au wires with diameters of 25mm are bonded on the diepads of Ag leadframes. For simplicity, wire loops are oriented perpendicular to the ultrasonic direction. It was found that the crescent bond breaking force by pulling the wire loop (pull force) with insulated Au wire is about 80 % of that of bare Au wire. A modification of the crescent bonding process is made to increase the pull force with insulated Au wire. In the modified process, an insulation layer removing stage (cleaning stage) is inserted before the bonding stage. The cleaning stage consists of a scratching motion (shift) toward to the ball bond in combination with ultrasound. Bonds are then made on the fresh diepad with the insulation removed from the contact surface of the insulated Au wire. This process increases the pull force of the crescent bond up to 26% which makes it comparable to the results obtained with bare Au wire. An online tail breaking force measurement method is developed with a proximity sensor between wire clamp and horn. Detailed understanding of tail bond formation is achieved by studying tail bond imprints with scanning electron microscopy and energy dispersive x-ray analysis. Descriptions are given of the dependence of the tail breaking force on the bonding parameters, metallization variation, and cleanliness of the bond pad. Simultaneous optimization with pull force and tail breaking force can optimize the Cu wire bonding process both with high quality and robustness. It is recommended to first carry out conventional pull force optimization followed by a minimization of the bonding force parameter to the lowest value still fulfilling the pull force cpk requirement. The tail bond forms not only under the capillary chamfer, but also under the capillary hole. The tail breaking force includes both the interfacial bond breaking strength and the breaking strength of the thinned portion of the wire that will remain at the substrate as residue. Close investigations of the tail bond imprint with scanning electron microscopy indicate the presence of fractures of the substrate indicating substrate material being picked up by Cu wire tail. Pick up is found on Au and Cu wires, but the amount of pick up is much larger on Cu wire. The effect on the hardness of the subsequently formed Cu free air ball (FAB) as investigated with scanning electron microscopy and micro - hardness test shows that Cu FABs containing Au and Ag pick ups are softer than those without pick up. However, the hardness varies significantly more with Au pick up. The amount of Au pick up is estimated higher than 0.03 % of the subsequently formed FAB volume, exceeding typical impurity and dopant concentrations (0.01 %) added during manufacturing of the wire.

The compatibility properties of some contemporary finish coats together with their complementary layers used in insulated exterior walls were examined in terms of water vapour permeability and modulus of elasticity. Basic physical and mechanical properties of some synthetic-, cement- and polymer-based external finish coats were analyzed in laboratory. Some additional samples, complementing the wall section, were also examined for their water vapour permeability. Results showed that the finish coats were high vapour permeable although they had high resistance to water vapour permeation, which was achieved by their application in thin layers. Cement-based undercoats were found to be medium permeable. The application of primer and/or paint was found to decrease the permeability of finish coats in different ranges. Thermal insulation layer was found to interrupt water vapour flow considerably. Among polystyrene- and mineral-wool-based thermal insulation boards, rockwool was recommended as the insulation layer due to its medium vapour permeability. In conclusion, walls insulated externally with rockwool boards and plastered with polymer-based finish coat, FC8ACB or synthetic-based finish coat FC3SB were found to be the most proper combination in terms of breathing and thermal resistance capabilities. All finish coats seemed to have sufficient strength and except the synthetic-based finish coat, FC2SB, they seemed to be compatible with each other and with the masonry in terms of their Emod values. Further studies were recommended on some other compatibility properties of finishing systems, such as thermal and moisture dilatation properties, and on the relation between the resistance to water vapour permeation and water permeability.

As energy certification programs and mandatory governmental building codes demand better building energy performance, the development of durable, highly insulated wall systems has become a top priority. Wood framed walls are the most common form of residential wall in North America and the materials used are vulnerable to moisture damage. This damage typically occurs first at the wall sheathing in the form of mould, fungal growth and rot. Increased thermal resistance can lead to two potential issues related to moisture durability: 1) increased potential for air leakage condensation at the sheathing and 2) decreased ability of the wall to dry after a wetting event. A natural exposure experimental study was performed at the University of Waterloo’s BEGHUT test facility to evaluate the hygrothermal performance of exterior insulated wall systems utilizing 3 different insulation types. These walls had approximately 2/3 of their total thermal resistance interior to the sheathing and 1/3 exterior to the sheathing. These walls were compared to a standard construction wall and a highly insulated double stud wall system. The test walls were evaluated during as-built conditions and during imposed wetting conditions. Moisture was introduced into the walls in two phases. The air injection wetting phase was designed to evaluate air leakage condensation potential during winter conditions, and the wetting mat wetting phase simulated an exterior rain leak and was used to evaluate the drying potential of the test walls. Hourly temperature, relative humidity and moisture content measurements were taken at multiple locations within each test wall. This data was analyzed to determine the air leakage condensation potential and the drying capability of each test wall. Results showed that the effective thermal resistance of the polyisocyanurate (PIC) insulation was significantly less than its nominal R-value rating under cold and moderate temperature conditions, and slightly higher under hot conditions. The effective thermal resistance of the extruded polystyrene (XPS) insulation was slightly less than its rated value under cold and moderate temperature conditions and significantly less under hot conditions. The rockwool (RW) insulation performed slightly above its rated thermal resistance under cold and moderate conditions and slightly less under hot conditions. Results also showed that only the double stud wall was vulnerable to winter-time interstitial condensation during the as-built (air-sealed) condition. This was a result of the hygroscopic nature of the cellulose insulation and a large temperature gradient across the insulation cavity. During the air leakage wetting phase, all of the exterior insulated walls showed a significantly decreased risk of air leakage condensation compared to the Datum and Double stud walls. During and following the wetting mat wetting phase, the PIC and XPS walls showed significantly reduced drying capability, while the RW wall showed a small reduction in drying capacity compared to the Datum and Double stud walls. It was concluded that adding insulation exterior to the wall sheathing can be an effective method to minimize air leakage condensation. The minimum ratio of exterior to interior insulation, however, must be suitable for the local climate and interior humidity conditions. Exterior insulation materials with low vapour permeability can significantly reduce the drying capacity of a wall system, but may be appropriate where exterior solar vapour drive is a concern or sufficient drying to the interior is available. Exterior insulation materials with high vapour permeability facilitate drying to the exterior and dry nearly as well as wall systems with no exterior insulation.

Thesis (Ph. D.)--Michigan State University. Dept. of Electrical and Computer Engineering, 2008. / Title from PDF t.p. (viewed on July 23, 2009) Includes bibliographical references (p. 243-252). Also issued in print.

Sulphur hexafluoride gas is the dominant insulation and interruption material in high voltage gas insulated substation. Its usage remains a concern of transmission system operators owing to the global warming potential of the gas. The work carried out in this thesis aims to find the environment-friendly materials that can replace SF6. These candidates are required to have a strong dielectric strength for high voltage busbar insulation and well arc extinguishing capability necessary for high voltage circuit breaker.A range of alternative insulation types including CF3I gas and its mixture, high pressure air and solid insulating foam are considered as substitute of SF6. Theoretical studies on the dimensions of busbars used in substations are carried out for these options. The dimension of the dielectric system and its ampacity of respect system are calculated using heat transfer models considering their boiling point and proper working pressure which is related with the dielectric strength of some gas.On the other hand, SF6 gas circuit breaker is extremely popular on the medium and high voltage power networks owning to its effective arc extinguishing performance. It would be ideal if a substitute material could be found for SF6 as an interruption material. Biodegradable oil PTFE ablation, other gas candidates including N2, CF3I are investigated as possible replacement of SF6 through literature study.The usage of vacuum circuit breaker is eventually capable to operate in high voltage transmission system. Simulations have been carried out with software ATP/EMTP to investigate the influence of different characteristics of vacuum circuit breaker including chopping current level, the dielectric strength of vacuum gap and the opening time. And then the probability of overvoltages when vacuum circuit breakers installed is studied by statistical study in MATLAB.

The diploma thesis deals with the optimization of powder-coating process resulting in a reduction of labor intensity during finishing components in gas insulated switchgear (GIS). The thesis is divided into five main chapters that describe characteristic and function of gas insulated switchgear (GIS), the theory of powder-coating, including mechanical and chemical pretreatment of surfaces, the studies of contemporary quality of coating process in the company ABB s.r.o. with classification of components of GIS according to their function. This chapter also contains detailed analysis of section of coating process during the processing of selected parts (housing and conductor). The thesis also contains detailed studies of masking of surfaces at coating parts, specifies the most common defects and determines the main cause presented in a well-arranged chart, design, description and realization of optimization solutions with selection and evaluation of final version. An economic comparison of contemporary condition of powder-coating process with designed optimization solution is stated at the end of the thesis.

Die Arbeit beschreibt die Entwicklung und Evaluierung einer Technologieplattform für die Herstellung von oberflächennahen Mikrostrukturen mit hohen Aspektverhältnissen. Grundlage dieser Technologieplattform stellt ein neuartiges Konzept zur mechanischen und elektrischen Kontaktierung beweglicher Elemente mittels spezieller Träger dar, deren typische Breite unterhalb eines Mikrometers liegt. Basierend hierauf werden drei unterschiedliche Prozessabläufe zur Herstellung der Mikrostrukturen, auch als Air gap Insulated Microstructures (AIM) bezeichnet, vorgestellt. Der Schwerpunkt dieser Arbeit liegt dabei auf der mehrschichtigen Trägervariante mit Isolationsebene und Leitungsebene. Verschiedene Schichtkombinationen, bestehend aus Siliziumnitrid, Siliziumdioxid und Aluminium, sind in ihrem mechanischen, thermischen und Langzeitverhalten charakterisiert und im Hinblick auf ihre Anwendbarkeit für die Träger bewertet. Für die Strukturierung der Siliziumelemente wird ein Verfahren basierend auf einem CF-Polymer als Passivierungsschicht beschrieben. Neben verschiedenen Ausfallmechanismen für die Passivierung werden gezielte Optimierungen der Abscheide- und Ätzprozesse erläutert sowie deren Resultate dargestellt. Für die vollständige Trennung von Substrat und seismischer Masse ist eine isotrope, vom Aspektverhältnis nahezu unabhängige Siliziumstrukturierung nötig. Entsprechende Betrachtungen und Untersuchungen hierzu, unter Verwendung der Reaktionsgase SF6 und O2, stellen den Abschluss der Untersuchungen zur Prozessentwicklung dar. Um die Leistungsfähigkeit der Technologieplattform zu demonstrieren, erfolgt die Herstellung verschiedener Sensoren und Aktoren. Die Charakterisierung dieser Elemente in ihrem mechanischen, thermischen und Langzeitverhalten stellt den Abschluss dieser Arbeit dar.

This dissertation presents the development of a new framework for international commercialization of innovative structural products in residential construction. Development of his framework required the examination of six subjects related to international commercialization. 1) commercialization models previously developed, locally and internationally, 2) barriers to the process, 3) stakeholders, actions, and decisions critical to the process, 4) characteristics of innovations that are suitable for international use, 5) characteristics of foreign markets that are ideal to adopt such innovations, and 6) strategies to overcome barriers The framework development was based on one structural product, SIPs. This product has been successfully developed and implemented in the United States and is being considered for commercial use in Saudi Arabia. Structural product clusters are particularly appropriate because of their innovative nature and their major influence on the structure of residential buildings. The study relies on sequential explanatory mixed-method research design, consisting of two distinct phases (Creswell 2003), to gain insight into processes surrounding commercialization. The rationale for this approach is that quantitative data and its results provide a general picture of the barriers to international commercialization in the available sample, which can mapped onto an initial framework. The qualitative data and its analysis help to refine and expand statistical results by exploring participants' actual decision processes that can be also mapped to a second framework. Both data sets can be merged, mapped onto one final framework. Variables related to the six subjects, mentioned above, were distilled from literature into open-ended questionnaires for two groups of key stakeholders in the supply chain of innovative structural products: 1) SIPs stakeholders in the US and 2) stakeholders of innovative structural products in Saudi Arabia. The primary purpose of the open-ended questionnaires was to ensure usage of correct terminology used in this study and to encourage full, meaningful answers—capturing all possible factors affecting the process of international commercialization. The author collected responses using web-based surveys. The results yielded the development of a reliable instrument to be implemented in further steps of this research. Next, the researcher collected variables related to the questions from previous open-ended questionnaires into closed-ended questionnaires to collect the data (on perceived barriers to international commercialization), using web-based surveys, and performed a preliminary analysis of the data using frequency analysis. This process yielded market-based strategies for developing an initial framework for international commercialization in residential construction. Subsequently, a focused examination of barriers to international commercialization was needed. The researcher collected such data through an applied understanding of the specific development processes for SIPs to be introduced to a new, international market, namely Saudi Arabia. Based on the model's structure, the researcher conducted six case studies of real stakeholder processes along the supply chain, SIPs development domestically and internationally, and tracked data for real risks of the commercialization process. Findings suggested perceived versus actual risks and barriers to the commercialization process for an integral product to the residential construction process. This was an important distinction because of proposed development methods and the application of market diffusion. Based on the barriers identified, the researcher developed market-based strategies to be incorporated into a second framework. This framework along with the initial framework and the literature-based framework have been triangulated to develop one final framework. The final framework was then introduced to a few experts in the industry to increase its validity. / Ph. D.

The main goal of this research is to develop new and innovative designs for insulated rail joints for improved life cycle and higher cost effectiveness. The research focuses on using electrically insulating materials that replace the epoxy used in current bonded insulated joints. Insulated joints (commonly known as "IJ") are widely used on railways to electrically insulate rail segments from each other, while mechanically connecting them together. The electrical insulation is necessary for accommodating track signals. The mechanical strength is needed to ensure the rail and IJs are able to withstand the vertical, longitudinal, and lateral forces that commonly occur on track. Insulating materials that can replace the epoxy used in bonded insulated joints are researched. The electrical insulation properties and mechanical strength of different materials are examined to determine the suitability of different materials for use in insulated joint. The most promising materials for use are determined to be fiber reinforced polymers and ceramics. Insulated joint designs are developed to accentuate the strengths of these two materials. The Insulating Metal Composite (IMC) insulated joint design that uses ceramics is determined to be the most promising of the new designs and is pursued through prototype fabrication. This particular joint design is analyzed structurally using both closed form analysis and FEA analysis using the software package ABAQUS. Electrical analysis using PSPICE is carried out on the joint. Prototypes of several design iterations of the insulating metal composites are built and tested. A proof of concept static bending test of the insulating metal composites used to build the IMC insulated joint is performed using a Tinius Olsen compressive tester. A rolling-wheel load test is performed on a prototype IMC component installed in rail. Finally, a prototype of a complete IMC insulated joint is fabricated and installed on the FAST test track at TTCI facility in Pueblo, Colorado for field evaluation. Electrical testing using a megohmmeter is performed on a complete prototype joint. Structural analysis shows that the components used to construct the IMC insulated joint can withstand the vertical and longitudinal loads applied to them. Electrical analysis shows that the joint can provide adequate electrical insulation and provides the required dielectric strength in the AREMA Manual for Railway Engineering. The proof of concept test shows that an IMC component can withstand 100 kips of static load without damage. The rolling-wheel load test shows that the ceramic in the IMC components can withstand a large shock load and that the rail used in the IMC insulated joints can survive repeated and shock loads. The testing of the prototype joint on the FAST track, which is ongoing at this time has shown that the new joint concept is fully capable of providing adequate electrical insulation and mechanical strength throughout the expected life of IJs. / Master of Science

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