A series of research studies have recently identified an issue called strain localization in welded wire reinforced (WWR) members. This phenomenon reportedly concentrates strains at welded cross wire locations and severely limit ductility. Those that identified the phenomenon used it to imply that WWR is unsafe because it does not warn of failure. This dissertation is investigating details to mitigate the strain localization effect and demonstrate the WWR can be used safely. A moment curvature analysis is developed using Response2000 program and calibrated using experimental data. Parametric study was developed to present a recommendation of details and minimum reinforcement required for WWR slabs. The effect of different types of WWR coating on mechanical properties were investigated. The dissertation next examined the effects of strain rate on the mechanical properties of WWR and traditional rebar. In total, fifty four slabs have been constructed using WWR and rebar with various cross wire spacing, using a realistic design. The strain localization phenomenon was not demonstrated, but WWR slabs are somewhat less ductile than traditionally reinforced members. The WWR members were shown to provide adequate ductility for warning of impending failure visually and with a well-accepted ductility measure. The WWR members were also shown the ability of load redistribution. The effect of coating demonstrates that both galvanizing WWR and coating WWR with epoxy has a positive effect on mechanical properties, along with adding corrosion resistance. The effect of strain rate shows that increase in loading rate tend to increase the yield and ultimate stresses and percent area reduction, however the loading rate increase does not have a significant effect on elastic modulus, elongation and uniform elongation.

Mechanically Stabilized Earth (MSE) walls have provided an effective solution to constructing retaining walls. The engineering and construction industry is continually striving to provide more cost-effective and design-efficient means to building MSE walls. Hilfiker Retaining Walls has developed a new semi-extensible metal mat reinforcement technology which does not fit into the current extensible or inextensible categories as defined by regulating authorities. The objective of this project was to construct and observe the behavior collect quantitative data for a 20-foot tall MSE wall using the prototype semi-extensible reinforcement technology. The results were compared to expected American Association of State Highway and Transportation Officials Load Reduction Factored Design values and was also compared to another case study, Prediction of Reinforcement Loads in Reinforced Soil Walls as conducted by Tony M. Allen, P.E., and Richard J. Bathurst, Ph. D., P. Eng. Comparing the behavior of the 20-foot prototype MSE wall to these design regulations and case studies allowed for proper classification and will facilitate future industry design efforts.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Robert Erik Grip. / M.S.

The focus of this thesis is the design, manufacturing and testing of a deployable radio antenna for the ORCASat nanosatellite. First, the context, motivation, requirements, as well as constraints for this project are introduced. Next, a brief overview of theoretical concepts relevant to the contents of this thesis are presented. After the introduction of the relevant background and theory, a literature review is undertaken, and an experiment-based methodology is established. Prior to conceptualizing a new design, detailed consideration is also given to previous attempts at designing a dipole for ORCASat. The root cause of the problems with these attempts is determined experimentally as the presence of ground planes on the circuit board supporting the antenna. After this preliminary investigation, the blocks required for the ORCASat antenna are introduced as the transmission line feeder, the balun, the impedance matching block, and the antenna arm feed. For each of these components, competing design concepts are developed, and the advantages and disadvantages of each of these concepts are presented. After this, the winning design concept is selected and developed into a manufacturable design. This design is identified as a tunable tape spring half wave dipole antenna featuring a specialized feed with electrically and mechanically optimal characteristics, no impedance matching, and a lossy choke balun wound from the coaxial cable feeder, all mounted on a circuit board in a pre-existing Delrin antenna deployer. Next, the manufacturing and assembly of this design is undertaken, followed by the consideration of an informal commissioning procedure. As part of this, a test article consisting of an incomplete prototype of the dipole is tested, and it is shown to have desirable voltage standing wave ratio, input impedance, and return loss characteristics, as well as excellent tunability. Having established that this test article is a good candidate to meet project requirements, it is updated to include as many of the final components of the antenna as possible. Then, formal test procedures for the verification of the tunability, return loss, VSWR, input impedance, antenna pattern, and absolute gain are established, and executed. Based on the results of this formal verification test campaign, it is concluded that the test article meets the requirements presented at the beginning of this thesis, and it is suitable as a radio antenna for the ORCASat mission. After this, the work is concluded by a set of recommendations for future work to prepare the antenna developed in this thesis for flight. / Graduate

No description available.

I den här rapporten presenteras en konstruktion av en ny rörrensningsmaskin som beställts av ett företag verkande inom rörrensningsbranschen. Konstruktionen som togs fram har; en grund i plast, vilken kan formgjutas i ett stycke, en modul med alla komponenter samlade inne i rörrensningsmaskinens trumma, teleskophandtag som gör den lätt att förvara, samt förvaringsmöjligheter för extra tillbehör. Prestandan på maskinen har optimerats genom mätserier och beräkningar, vilket gett en optimal effekt, vikt och storlek. Rörrensningsmaskinen modellerades i Solid Edge, och vissa av delarna analyserades därefter i Ansys. Till rörrensningsmaskinens vajer konstruerades en växel som ska lösa problemen med vibrationer och värmeutveckling. En prototyptillverkning på denna växel gjordes för att testa om den löste problemen, vilket dock inte kommer att presenteras i denna rapport av konfidentiella skäl. / This report will present a design study of a new development of a pipe cleaning machine, which is ordered by a company working in the plumbing industry. The design that has been developed consists of; a base structure made in plastic material, which can be mold casted in one piece, a module that places all the components inside the drum, telescopic handles which make the machine easy to store, and storage locations for additional accessories. The performance of the machine has been optimized by test studies and calculations, which has given the optimal power, weight and dimensions. The pipe cleaning machine was modeled in Solid Edge, and then imported into Ansys for further calculations. To solve problems with vibrations and heat generations along the wire, a gear was designed. This gear was later manufactured and tested to be able to verify that the described problems were solved. This part is, however, not included in this report for reasons of confidentiality.

No description available.

Through Silicon Vias (TSVs) are vertical interconnections providing the shortest possible signal paths between vertically stacked chips in 3D packaging. In this thesis, TSVs are fabricated and two novel approaches for the metal filling of TSVs are investigated. A wire bonder is utilized to apply TSV core material in the form of gold stud bumps. The metal filling approaches are carried out by 1) squeezing stud bumps down the TSV holes by utilizing a wafer bonder and 2) stacking stud bumps on the outer periphery of the TSV holes and thereby forcing the material further down. Both approaches have successfully filled TSV holes of varying depths and no voids have been observed. The squeezing approach reaches measured depths of up to 52.9 μm and the stacking approach reaches depths of up to 100 μm.

Through translations and transformations, my degree project aims to explore what makes something – space, or an object– charged. I am investigating ways to create objects with the starting point in two pieces of furniture, analyzing them both in their everyday contexts, and in certain works of art. This has resulted in the creation of two works that I have called an imprint and a bench and a bed. The quality that I have been searching for in this project is what activates a subjective feeling of recognition that will stay in the mind of the beholder, a charge in an object that affects memory or consciousness. The way I explore this quality is by analyzing the terms Eros and punctum and by investigating the relationship between the abstract and the figurative, examining the bodily connection to the objects and the surrounding.

Aging aircraft wiring poses a significant threat to both commercial and military aircraft. Recent air disasters involving aging aircraft wiring have made it clear that aging wiring can be catastrophic. Aging of an electrical wiring system can result in loss of critical functions of equipment or loss of information regarding equipment operation. Either result can lead to an electrical failure causing smoke and fire, consequently being a danger to public health and aircraft safety. Conventional maintenance practices do not effectively manage aging wiring problems. More proactive methods are needed so that aircraft wiring failures can be anticipated and wiring systems can be repaired or replaced before failures occur. This thesis will identify the effects of aging wiring systems, the potential degradation to aircraft safety and regulations regarding aircraft wire safety. This thesis will evaluate the conventional wire maintenance practices and transition wire integrity programs in the aviation industry.