Nine adults with single-sided deafness previously implanted with a Baha were given a two-week trial with a CROS hearing aid and tested in unaided and aided conditions. Both devices were compared on head shadow effect reduction, speech perception measures, self-assessment questionnaires, and daily diaries. The CROS reduced the head shadow effect for more frequencies than the Baha. Participants performed well across all conditions with speech to the poor ear in quiet. The QuickSIN showed both devices adversely affected speech perception with noise to the poor ear; the CROS was more disadvantageous. Neither device improved speech perception with noise to the better ear. The BBSS and SSQ demonstrated subjective benefit and the diaries indicated frequent use of both devices. Five participants preferred the CROS for sound quality; three preferred the Baha for comfort. As both devices seem comparable, a CROS should be the first intervention option recommended before considering Baha surgery.

Master of Science / Department of Electrical and Computer Engineering / William B. Kuhn / An important concern for high speed circuit designs is that of crosstalk and electromagnetic interference. In PCB board-level designs, crosstalk at microwave frequencies may result from imperfections in shielding of PCB interconnects or more generally transmission lines. Several studies have been done to characterize and improve the isolation between PCB transmission lines for both digital and RF circuits. For example, previous studies in the microwave region have examined the effect that line type, line length, and separation have on crosstalk and suggest that without full shielding, the upper limit of isolation is on the order of 60dB for traditional board-level lines [1]. In order to more fully characterize crosstalk and improve isolation above 60 dB, this thesis studies signal-to-ground-plane separation, considers advanced line types, and examines the effect of 3D shielding. Results are presented from 100MHz to 30GHz for the traditional transmission line structures of microstrip, CPW, differential pair and CPW differential pair. This study shows that with a halving of distance between signal and ground planes, isolation between transmission lines can be reduced by as much as 20dB, making this one of the best ways to improve performance. Advanced methods of shielding are then presented. Direct launch stripline and single-sided CPW improve upon existing crosstalk reduction techniques, while split shielding and ablation of dielectric PCB material are also proposed. The data and additional crosstalk reduction techniques discussed in this thesis serve two purposes. One: with a more complete understanding of the effects that transmission line types and parameters have on crosstalk, engineers can quickly identify potential crosstalk issues and resolve them before manufacturing. Second, this thesis presents the engineer with four new additional techniques that may become available in advanced manufacturing environments. Such techniques can further reduce crosstalk and may allow for isolation values to approach 100 dB at the PC board level.

Natural ventilation is an effective method to save energy required to condition buildings and to improve indoor air quality. Computational fluid dynamics (CFD) was used to model single-sided buoyancy-driven natural ventilation in a single room with a heater and door. The velocity and temperature profiles at the doorway agreed fairly well with published literature that includes Mahajan's experimental [2] and Schaelin et al's numerical studies [1]. The 2D and 3D models predicted the neutral level with a difference of 5.6 % and 0.08 % compared to the experimental results, respectively. Using solutions at the doorway, heat transfer rates were calculated. More realistic situations were studied considering conduction, various ambient conditions, wind speeds, and additional heat sources and furniture in the room. The heat loss through the wall was modeled and the airflow and temperature within the room showed no significant changes despite modeling conduction through the walls. Various ambient temperatures and wind speeds were tested, and the neutral level height and total heat transfer rate through the doorway increased with decreasing ambient temperatures. However, the neutral level did not significantly change as wind speeds varied. Total heat transfer rate at the doorway became positive, that is heat transferred into the room, with wind speed. Lastly, the effect of additional heat sources (mini-refrigerator, monitor and computer) and furniture (bookshelf, desk, chair and box) on airflow and heat transfer in the room was analyzed by comparing with a simple case of a room with a heater. Large velocities and high temperatures were predicted in the vicinity of the heat sources. However, the spatially averaged velocity and temperature did not change significantly despite additional heat sources. The room with furniture was modeled at lower ambient temperature, where the spatially averaged velocities were larger and temperatures were lower than the simple case. The room heated up and reached its thermal comfort level, but the velocities exceeded the maximum acceptable level set by ASHRAE guidelines [8]. Wind was considered simultaneously with the lower temperature, and the room was cooled faster with wind. However, the room was never able to achieve the comfortable level both in velocity and temperature. / Master of Science

The University of Gotland has between the years 2006-2011 conducted seminar excavations in Västergarn parish, Gotland. During this time 167 comb fragments have been registered. Out of these are 51 of importance for this study, since they are defined as either a single-sided composite comb or a comb case. The purpose of this thesis is to enlighten the earliest period in the history of Västergarn by focusing on the earliest forms of combs and their cases. And as the title expresses do the combs date to the Viking Age or the Middle Ages? The combs from the excavations will be compared to different type schemes, both Viking Age and Middle Age and different places in Scandinavia such as Lund, Oslo, Lödöse and Gotland. The conclusion of the analysis is that the combs from Västergarn are from the late 11th century to the early 13th century, during the Early Middle Age.

Most electrical machines available in the market utilise some form of silicon iron (SI) as the core material. Although SI based electrical machine manufacturing methods are well established and simple, SI has significant iron losses specifically in high frequency variable-speed motor drive applications. Two alternative magnetic materials have recently been developed: amorphous magnetic material (AMM) and soft magnetic composite, which can each offer unique characteristics that can be utilised to improve the performance of electric machines. AMM offers extremely low iron losses which makes it a good candidate for high-efficiency and variable-speed motor applications. However, due to handling and cutting limitations, AMM has not been utilised widely in rotating electrical machines. A commercially viable AMM cutting technique was recently developed by the industrial partner of this project. It is thus now practical to cut the AMM ribbon into a machine stator, particularly for axial-field stators which generally require less cutting than radial-field stators. This thesis investigates an innovative motor design based on applying the cut AMM in an axial-field permanent magnet (AFPM) machine for general drive applications. It includes a detailed review of the analytical approach, finite element analysis (FEA), iron loss investigation and prototype performance comparisons. Analytical analysis of the AFPM machine was performed and the key design variables were evaluated to optimise the design parameters based on the use of AMM. The AMM cutting constraints, design and performances trade-offs were also investigated in the design. The research study provides a design procedure to determine the basic physical size and configuration (e.g. combination of the number of slots and poles, slot width and depth, number of winding layers, air gap length, magnet thickness) based on certain basic specifications. In addition, a comprehensive investigation was conducted on the iron loss of various materials to compare these with AMM. Due to the three dimensional (3D) nature of the AFPM structure, the theoretical design was validated using 3D FEA and extensive simulation results are provided. A number of AMM AFPM prototypes were successfully designed and constructed. Due to limited available materials, the prototypes were built using uncoatedAMMribbon which has substantially higher iron loss characteristics. Nevertheless, it is believed that it would still provide a valuable understanding of the real machine characteristics and allow initial design validation. The prototype was tested in a custom-built test rig to validate the analytical and 3D FEA predictions. Overall, a good correspondence between the results and predictions has been achieved. Extensive experiments have been conducted to investigate and demonstrate the characteristics of the AMM prototype machines which are based on fractional-slot concentratedwinding single-sided AFPM machines. This includes comparisons against identical silicon iron and soft magnetic composite prototypes. In addition, the laboratory experimental results also highlighted the significant effect of the open-circuit losses on the overall machine performance. Therefore, the open-circuit loss components which includes bearing, windage, magnet and iron losses were separated based on 3D FEA and experimental results. The above research studies demonstrated the potential and feasibility of cut AMM to produce highly efficient AFPM machines. In addition, the innovative cutting technique also has the potential for mass production of low-cost AMM machines. The research work in this thesis makes a significant contribution to the design of axial-field permanent magnet machines based on AMM. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1375647 / Thesis (Ph.D.) -- University of Adelaide, School of Electrical and Electronic Engineering, 2009

No description available.

Composite beams are frequently used in building, combining a steel beam with either a concrete-filled steel deck or solid concrete slab. To ensure proper composite action, shear connectors, typically in the form of headed shear studs, are utilized. Traditionally, the strength assessment of these headed shear studs is made using empirical design specifications that are based on push-out tests, which have been widely conducted and standardized over the years. However, the standardized push-out tests have short-comings, such as uneven slab bearing, slab buckling, questions regarding the distribution of load to each stud, etc. A study was conducted to evaluate and compare the existing push-out test setup with two alternative test setups. The study also aimed to examine the behavior of headed shear studs in composite beams having deck deeper the current allowable limit of 3 in., as specified by American Institute of Steel Construction (AISC) design specification. While the standard specification allows for steel decks with rib heights of up to 3 in., there are deck profiles deeper than 3 in. available in the market. Utilizing these deeper decks in composite beams offers several advantages, including faster and more cost-effective construction by reducing the number of beams required. This research therefore found that a major challenge in creating an alternative test setup involves eliminating moment at the interface between the concrete-filled steel deck and the steel beam. This moment leads to tension in the headed shear stud/stud group closest to the actuator, thus affecting the shear strength of the headed shear studs. Further, these headed shear studs have significant strength when used with 3.5 in. decks but further research is necessary. / Master of Science / Composite beams are widely used in building construction, combining a steel beam with either a concrete-filled steel deck or a solid concrete slab. To ensure their proper function, shear connectors are used, typically in the form of headed shear studs. Traditionally, the strength of these shear studs is determined using standardized push-out tests, but these tests some challenges like uneven slab bearing, questions about even load distribution, etc. In this study, the existing push-out test setup was evaluated and compared with two alternative setups. The behavior of headed shear studs in composite beams with deeper decks than the current allowable limit specified by design standards was also investigated. Using these deeper decks offers advantages such as faster and more cost-effective construction. One major challenge in creating an alternative test setup was eliminating the moment at the interface between the concrete-filled steel deck and the steel beam. This moment caused tension in the headed shear stud closest to the actuator, impacting the overall shear strength of the studs. Additionally, it was found that these shear studs show promising strength when used with 3.5 in. decks, but more research is needed to fully understand their capabilities. By exploring new test setups and considering deeper decks, this research contributes to improving the design and construction of composite beams, making them more efficient and reliable for future building projects.

For any business, surviving in a competitive market while maintaining all the operational performance indices up to mark is very crucial. There are several theories and techniques to improve the efficiency of the operational performances. Line balancing is one of those well practiced techniques used daily in most of the industries. Line balancing helps balance the assembly lines with regards to man, machine, takt times, etc. This thesis research was done with Electrolux laundry systems, Ljungby in Sweden. With the varying customer demands the case company was balancing its line manually using basic methods. As a part of lean development schemes, Electrolux Ljungby, wanted to transform the line balancing techniques from manual to a fully automated software. The purpose of this research is to determine the company-specific line balancing criteria which should be considered before performing line balancing. This research furthermore lays out a guideline to follow a smooth transition from the manual system of LB to an automated software by concluding the features the software must handle to perform the LB according to required objectives. A case study approach was utilized to collect all the required data to achieve the results. Using the data collection techniques such as interviews, observations and historical analysis we arrived at the data required to design the guidelines with regards to line balancing software features.  The findings suggest that the desired line balancing constraints which are very important in the multi model single sided straight-line balancing problems are flow of materials, assembly precedence, physical constraints, product demand, bill of materials, restricted processes, man power and desired line balancing objectives. Keeping these constraints into consideration the features which are desired in an onlooking line balancing software are the Integration of data and documents/ maximum control, mixed model and option intelligence and analysis, multiple resources, smart variant management, scenario management, yamazumi chart, constraints and reporting tabs. The findings of this thesis can be used as guidelines by any manufacturing industry while they consider buying a new software which can handle Line balancing problems. This research is one of its kind which talks purely about the constraints and desired features only in a specific line balancing scenario. Practitioners can use this as a base for conducting further research on constraints and features pertaining to it, for different line balancing scenarios.

Spatial hearing is crucial in real life but deteriorates in participants with severe sensorineural hearing loss or single-sided deafness. This ability can potentially be improved with a unilateral cochlear implant (CI). The present study investigated measures of sound localization in participants with single-sided deafness provided with a CI. Sound localization was measured separately at eight loudspeaker positions (4°, 30°, 60°, and 90°) on the CI side and on the normal-hearing side. Low- and high-frequency noise bursts were used in the tests to investigate possible differences in the processing of interaural time and level differences. Data were compared to normal-hearing adults aged between 20 and 83. In addition, the benefit of the CI in speech understanding in noise was compared to the localization ability. Fifteen out of 18 participants were able to localize signals on the CI side and on the normal-hearing side, although performance was highly variable across participants. Three participants always pointed to the normal-hearing side, irrespective of the location of the signal. The comparison with control data showed that participants had particular difficulties localizing sounds at frontal locations and on the CI side. In contrast to most previous results, participants were able to localize low-frequency signals, although they localized high-frequency signals more accurately. Speech understanding in noise was better with the CI compared to testing without CI, but only at a position where the CI also improved sound localization. Our data suggest that a CI can, to a large extent, restore localization in participants with single-sided deafness. Difficulties may remain at frontal locations and on the CI side. However, speech understanding in noise improves when wearing the CI. The treatment with a CI in these participants might provide real-world benefits, such as improved orientation in traffic and speech understanding in difficult listening situations.

Este trabalho apresenta um estudo numérico e experimental do comportamento estrutural das ligações viga mista-pilar com cantoneiras de assento e alma. No estudo teórico foi desenvolvido, com base nos EUROCODES 3 e 4, um procedimento para avaliação do comportamento das ligações mistas com cantoneiras de alma e assento e com chapa de topo. O trabalho de investigação experimental, abrangendo modelos submetidos a carregamentos monotônico e cíclico, foi realizado no Instituto Superior Técnico (IST), Portugal, em que o objetivo principal foi avaliar a influência da força axial de compressão no pilar para o comportamento do painel da alma do pilar, e conseqüentemente no comportamento global da ligação mista localizada em nó de extremidade. Nos ensaios experimentais foram analisadas as rotações e deformações no painel da alma do pilar sem e com enrijecedor na alma do pilar. Adicionalmente, a eficiência da ancoragem das barras de armadura longitudinal foi verificada. Paralelamente à investigação experimental, um estudo numérico de ligações mistas foi realizado por meio do modelo em elementos finitos, o qual mostrou-se representativo, tornando-se uma ferramenta para análises paramétricas. / This work presents a numerical and experimental study of the structural behavior of beam-to-column composite joints with bottom and web angle connections. In the theoretical study, basing in EUROCODES 3 and 4, an analytic procedure for evaluation the static behavior of beam-to-column composite joints with bottom and web angle connections was developed. The experimental test program, enclosing monotonic tests and a cyclic test, was carried out at the Instituto Superior Técnico of Lisbon (IST), where the main objective was to evaluate the effect of column axial load on column web panel and consequently in the global behavior of single-sided composite joint. In the tests, the panel zone rotations and deformations were analyzed for stiffened and unstiffened column web. In addition, the efficiency of the main rebar was verified. Finally, a thorough of finite element model, a numerical study of composite joints was developed. This model was found to be representative and reliable as a tool to futures parametric analyses.