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1
Wu, Tong-Ching Tom. "The performance of the ice hockey slap and wrist shots : the effects of stick construction and player skill." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33949.
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This thesis was to examine the interaction of players' skill level, body strength, and various types of stick construction and stiffness on the performance of the hockey shots. Forty subjects were tested, and each subject performed the slap and wrist shots with different stick shaft constructions and stiffness. Shot mechanics were evaluated by simultaneously recording of ground reaction forces, stick movements and peak puck velocity. Data analyzed with a 4-way ANOVA for several dependent variables. The results indicated that: (1) the slap shot was faster than the wrist shot corresponding to greater vertical force, stick bending and hand placement; (2) the puck velocity was influenced by skill level and body strength not stick type; and, (3) the skilled players generated greater vertical force and stick bending by adjusting their hand positions. Further studies are needed to address the specific stick material and construction properties.
2
Bennink, Dirk. "Design of solids separation equipment : a thesis." Thesis, Queensland University of Technology, 1989. https://eprints.qut.edu.au/36450/1/36450_Bennink_1989.pdf.
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This work covers a reassessment of the 'Hot Break'
separation problem by a mechanical engineer from outside the
brewing industry. The solid-liquid separation problem was
therefore investigated without prior knowledge of
constraints or current practices.
During the brewing of beer an unwanted, insoluble
precipitate, 'trub' is formed, reported to have undesirable
effects on the finished beer quality.
The existing equipment, 'whirlpool' separators, designed to
eliminate this 'trub' performed poorly, allowing much of the
precipitate to be carried over to subsequent processes.
To remedy the problem, a program to either:
1. design suitable replacement separators or;
2 • modify existing separators to enhance their
performance,
was pursued.
To evaluate possible alternative separators determination of
the relevant physical (solid, liquid) properties,
measurement of the process parameters at peak production,
and review of the chemical constraints was necessary.
Performance of the current whirlpool separators was
ascertained to establish the extent of the ~xisting problem.
Existing efficiencies set a benchmark for comparison against
proposed alternatives.
Through exhaustiv~ literature review, consultive advice, a
series of experiments and rig testing, an extensive range of
separation techniques was evaluated, A review of over
forty-five reports on whirlpool performance and design
practices, the majority of which being the basis of doctoral dissertations, combined with the evaluation of a third
whirlpool at Milton Brewery revealed whirlpools to be the
most suitable and logical choice.
It seemed that the inherent problems in whirlpool design
stem from the haphazard approach adopted by the brewing
industry. To redress this problem an exp~rimental program
to optimize whirlpool tank geometry and operation was
initiated. Both experimental and hardware design were
fundamentally different to all previous endeavors to
establish whirlpool design guidelines. A pilot plant was
designed and commissioned such that direct measurement of
the 'whirlpool' response independent of other secondary
effects was possible.
The experimental program produced · over two hundred
comparative whirlpool indices over a range of geometric and
operational configurations. These suggested that whirlpool
performance could be optimised in shallow vessels using low
inlet velocities.
Finally, the need for secondary separators to be used in
conjunction with whirlpool tanks would diminish with
improved primary separation.
3
Platten, A. K. "A study of evaporation and drying in porous building materials." Thesis, University of Manchester, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373625.
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Blaxton, Allen C. Fay Michael J. Hansen Cheryl M. Zuchristian Christopher M. "An analysis of USMC heavy construction equipment (HCE) requirements /." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Jun%5FBlaxton.pdf.
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Thesis (M.B.A.)--Naval Postgraduate School, June 2003.Thesis advisor(s): Donald R. Eaton, Joe G. San Miguel, Raymond E. Franck, Keebom Kang. "MBA professional report." Joint authors: Michael J. Fay, Cheryl M. Hansen, Christopher M. Zuchristian. Includes bibliographical references (p. 129-130). Also available online.
5
Spyrou, Evangelos. "The effect of shell geometry on the impact attenuating capabilities of ice hockey helmets relative to liner structural characteristics and impact conditions." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ29578.pdf.
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Parks, L. F. "A study of Kuwait marine clay and its suitability for production of synthetic aggregate and other building materials." Thesis, Brunel University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370679.
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Brocklesby, Martin. "The environmental impact of frame materials : an assessment of the embodied impacts for building frames in the UK construction industry." Thesis, University of Sheffield, 1999. http://etheses.whiterose.ac.uk/15041/.
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There are many important environmental issues involved in the construction and use of buildings which are either undergoing or require further research. The lack of detailed embodied energy assessments models has been identified and limits possible environmental analysis. This study examines the current state of research into the environmental impact of frame materials, assesses the quality and range of data available, sets up a new framework for evaluation of materials and uses several example structures to assess the environmental impact This has been achieved by, firstly, studying the environment related literature available concerning the frame of the building, separate from other considerations, to provide a clear understanding of the processes involved. Second, data is extracted from the literature and processed to provide a homogenous approach and level field from which frame analysis can take place. Gaps in the available data are identified. Third, the identified gaps are filled using data derived from sources ranging from manufacturers' literature to direct analysis of on site activities. Fourth, a model has been created to assess the environmental impact of the building frame. The factors assessed within the remit of environmental impact are: embodied energy, embodied CO2 and transportation hours. The embodied energy includes the primary energy for all raw materials, transportation, office overheads and contractor operations. These are calculated from the winning of raw materials, through manufacture, to demolition and recycling. Embodied CO2 encompasses the same range of data, but with respect to the CO2 transportation hours estimate the time spend on the road by vehicles involved in the embodied energy and CO2 calculations. Finally data from several buildings has been used, to evaluated the environmental merits of each with respect to each other and to other buildings for which calculations have been performed. Conclusions have been draw and. further work suggested.
8
Borthwick, Fiona. "The impact of the European Construction Products Directive on UK construction product manufacturers." Thesis, De Montfort University, 2002. http://hdl.handle.net/2086/13253.
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The research is based on the European Directive aimed at harmonising standards for construction products. Harmonised standards remove technical barriers to trade allowing manufacturers to sell their products anywhere in the European Economic Area (EEA) provided the product complies with the standard and has affixed the CE marking. This should lead to greater competition in all EEA markets. A review of relevant literature covered three distinct areas; developments of the European Union and the Construction Products Directive (CPD), the UK construction industry and materials sector and strategic management concentrating on market barriers and entry strategies. The research combined these areas together by investigating the impact of the CPD on the UK construction product manufacturers specifically considering the strategic decisions of the UK brick industry. As there was little previous empirical research into this area, data was generated through exploratory interviews with manufacturers and bodies involved with the UK implementation of the Directive, through a self-completion postal questionnaire survey with manufacturers from six product groups and by a case study approach used to examine the UK brick industry. The research demonstrated that the Directive is having little impact to date on the strategic decisions of UK construction product manufacturers. Also, there are a disturbing number of producers that were not aware of the Directive and its possible implications. By applying previous research findings to the UK brick industry, conclusions were drawn highlighting the specific nature of this industry and identifying specific characteristics that influence its competitiveness. The Directive and the UK brick industry have never previously been examined in such a manner and areas for further research have been suggested.
9
Webster, James. "The perception of comfort and fit of personal protective equipment in sport." Thesis, Loughborough University, 2010. https://dspace.lboro.ac.uk/2134/6242.
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During the design of sports equipment, the main focus is usually on physical performance attributes, neglecting key subjective factors such as feel and comfort. The personal protective equipment worn in sport is a typical example, where injury prevention has taken precedence over user comfort, but it is anticipated that with a new approach to the design process, comfort can be improved without sacrificing protection. Using cricket leg guards and taekwondo chest guards as an example, this study aimed to develop a systematic method for assessing user perceptions and incorporating them into the design process. Players perceptions of the factors that influence the comfort of cricket leg guards and taekwondo chest guards were elicited through the use of co-discovery sessions, focus groups and individual interviews, and analysed through an inductive process to produce a comfort model. The relative importance of each different comfort dimension was identified through the use of an online questionnaire utilising the analytical hierarchy process method. Through the combination of these methods, six general dimensions were identified with a weighting regarding the amount to which each one determines a user's perceived comfort. For both cricket and taekwondo, the majority of players ranked Fit as the most important factor affecting comfort. Experimental procedures were developed to objectively test the Fit of cricket leg guards, with regards to batting kinematics, running performance and contact pressure. These methods were combined with subjective assessments of leg guard performance, to determine if there was a relationship between users perceived comfort and objective test results. It was found that shot ROM and performance were not significantly affected by cricket leg guards, despite perceptions of increased restriction whilst wearing certain pads. Wearing cricket leg guards was found to significantly decrease running performance when compared to running without pads (p<0.05). In addition, it was found that the degree of impedance depended on pad design and could not solely be attributed to additional mass. These results correlated with the subjective assessment of three different leg guards, with respondents identifying the pad which had the largest influence on their running biomechanics and impeded their performance the most, as the most restrictive pad. Contact pressure under the pad and straps was also measured for four different leg guards whilst running. The results found that the top strap applied the greatest amount of pressure to the leg, especially at the point of maximum knee flexion. The peak pressure under the top strap was found to reach up to three times that of any other area of the pad. These results were reflected in the subjective assessment of the leg guards, with all nine subjects identifying the top strap as an area of discomfort for certain pads. The results also suggested there was a preference for pads with a larger more consistent contact area, as pad movement was perceived to increase when contact area variation was greater. Finally the results from this research were used to develop a product design specification (PDS) for a cricket leg guard, specifying size, mass, contact pressure and shape. The PDS was used to develop a concept design which would maximise comfort, whilst maintaining protection.
10
Al-Nakeeb, Ahmed A. R. "An assessment of the effectiveness of Quality Assurance Systems in the construction industry." Thesis, University of South Wales, 2000. https://pure.southwales.ac.uk/en/studentthesis/an-assessment-of-the-effectiveness-of-quality-assurance-systems-in-the-construction-industry(bb4ec2f0-37e6-46dc-85e6-3945cfc1da57).html.
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More than two decades have passed since the introduction of Quality Assurance Systems in the form of BS 5750/ISO 9000 yet the effectiveness of these systems are still a matter of controversy and debate. Although the implementation of Quality Assurance Systems in the construction industry has been slow to emerge, most large construction organisations are currently implementing such systems. Much has been written about the advantages and disadvantages of Quality Assurance Systems but unfortunately without any direct reference to any hard data. Most of the reported advantages and disadvantages are based purely on perceptions and views of individuals involved. The British Standards Institution (BSI) acts as a collaborating establishment for this research. This is the first research that attempts to assess the effectiveness of Quality Assurance Systems, in the construction industry. Based on data collected from literature, construction companies and experts in the field of Quality Management, the research provides a better understanding of the objectivity of available data regarding the effectiveness of QA Systems and examines the possibility of fording reliable measures. This thesis shows that no construction company has managed to assess the effectiveness of its Quality Assurance Systems in an objective manner. Regarding measures of the effectiveness of QA Systems, most experts believed that such measures are very important because an organisation must justify the existence of such systems, which are considered as overheads. However, all experts declared 1 that they are not aware of any construction company that has managed to assess the effectiveness of its ISO 9000 in any reliable manner. This research is of a particular value to construction companies who are considering implementing an ISO 9000 as well as those companies that are already implementing such systems.
11
Branch, James. "Plastic properties of fresh high strength concrete." Thesis, University of Surrey, 2001. http://epubs.surrey.ac.uk/842953/.
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This thesis describes the novel test techniques that were developed to measure the parameters associated with the plastic shrinkage, and subsequent possible plastic shrinkage cracking, of high strength concrete. The parameters measured during the first 24 hours after placing were the stress- strain relationship, negative pore pressure and free shrinkage strain development. The plastic behaviour of eight high strength concrete mixes was quantified and these mixes were then tested to assess their propensity towards plastic shrinkage cracking, using restrained ring tests. A review of the parameters associated with plastic shrinkage cracking was carried out. The general view was that as the particle size in a cement matrix gets smaller, then the negative pore pressures developed are greater and hence shrinkage increases. This meant that the presence of secondary cementing materials, of very small diameter, such as microsilica, in high strength concretes would explain their apparent susceptibility to plastic shrinkage cracking. Eight high strength concrete mixes were tested in exposed and sealed conditions. It was found that when tested in sealed conditions none of the parameters measured presented itself as the sole driving force behind plastic shrinkage or plastic shrinkage cracking. Also, when cured in sealed conditions, none of the mixes tested in the restrained ring test apparatus cracked. When tested in exposed conditions, the presence of wind had little effect on the stress-strain relationship of the mixes tested. However the presence of wind seemed to cause negative pore pressures to develop earlier than in the sealed samples and increased free shrinkage by 3 to 40 times depending on the mix. The samples that exhibited the highest free shrinkage strains, in exposed conditions, were the mixes that cracked when tested in the restrained shrinkage rings. The mixes that cracked all contained microsilica and these mixes did not crack when the same mixes were tested without microsilica. Polypropylene fibres were found to reduce the cracked area of the samples that cracked. The supplementary cementing materials used in this study were ground granulated blast furnace slag, metakaolin, microsilica and pulverised fuel ash.
12
McNeely, James Noah. "The design of a mechanical device for making baby food." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/23159.
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Zuo, Yiying 1974. "Design, analysis, and implementation of multi-port refraction based electro-optic switches." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103035.
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Electro-optic (EO) beam deflectors are voltage-controlled devices widely used for scanning and switching applications. For example, high-speed, low-loss optical switches aimed at future optical networks can be built on EO deflectors. Novel EO deflectors distinguish themselves with a much-improved steering performance, high-speed response and simple fabrication requirements. Patterned ferroelectric crystals such as LiTaO3 are first poled to provide the required prism shaped domain structures. The application of an electrical field across the entire crystal can then be used to drive the trajectory of the beam as it travels through the poled wafer. The electric field induces an index change of opposite magnitude on the adjacent domain regions in the EO device, causing the optical beam to refract at the interfaces.Although rectangular geometry is extensively employed in EO devices, nonrectangular scanners have demonstrated better deflection performance. Two new nonrectangular geometries capable of further enhancing the deflection performance of EO beam scanners, proposed in this dissertation, were constructed. Their parabola and half-horn geometries provide 2-3 degrees of steering, which is 2-3 times greater than the steering provided by rectangular deflectors.
EO deflectors based on the parabola and the half-horn geometries, which can provide larger deflection angles, were built. These devices demonstrated a deflection angle of 3.1°, less than 5 dB of insertion loss from fiber to fiber, and -40 dB of crosstalk.
Two packaged optical switches using rectangular EO deflectors were demonstrated. By combining these EO deflectors with fiber collimators and high voltage packaging, high speed optical switches were built and characterized. The switch design was based on a 500mum z-cut LiTaO3 single crystal wafer fabricated using the domain inversion method. The 1x2 switch had a maximum deflection angle of 1.22° with an applied voltage of 1.1 kV and the 1x4 switch had a maximum deviation angle of 2.14°, with an applied voltage of 1 kV. The average insertion loss and crosstalk figures were 2.36 dB and -36 dB, respectively. The worst case switching time was 86 ns.
14
Bibby, Lee. "Improving design management techniques in construction." Thesis, Loughborough University, 2003. https://dspace.lboro.ac.uk/2134/793.
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Recent years has seen a significant drive away from traditional procurement routes with contractors finding themselves with an increasing responsibility for control of design - a process they have had little experience in managing. They now have to adapt accordingly. The learning curve is steep, not least because many projects must now be delivered fast track while co-ordinating increasingly complex fabric and content of buildings without a platform of accepted good practice to manage the design process. This is a major factor preventing the UK construction industry from delivering projects on time, to budget and to the specified quality. There is a need to educate an increasing number of people in design management techniques to equip them to manage today's fast moving and demanding projects. However, many current design management tools are insufficiently developed for industry application. Therefore, to improve design management in the industry, current techniques must be modified to align them with the needs of the modern design manager. This research has developed and tested a training initiative aimed at improving design management practice within a major UK Design and Construct Contractor. It comprises a Design Management Handbook, Design Management Training, Team Support and Project Monitoring. The Design Management Handbook is the core of the training initiative. It addresses critical aspects of design management practice and provides design management tools. Training provides guidance to project teams on the tools and practices. In Team Support project teams are supported in the implementation of the new practices and tools to help embed new ways of working in company practice. Project Monitoring establishes the impact of the new practices on project performance to demonstrate that they are working and thus reinforce change. To establish the training initiative's effectiveness and key findings, the impact of the initiative on design management performance has been explored. The research has established which practices and tools were used, which were not, as well as an understanding the applicability and performance of each Handbook practice and tool. From this, barriers to implementing new design management tools in industry were identified and strategies developed in order to overcome such barriers.
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Patel, Umesh. "Control authority and the design of active controllers for buffet suppression of the F-15 and F/A-18." Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/12161.
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Argon, Cenk. "Turbo product codes for optical communications and data storage." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/15350.
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Schmitt, Robert Joseph. "The design of a flexible fixturing system." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/17958.
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Liu, Li, and 劉荔. "Compact planar UWB antennas for wireless device applications." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/207199.
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The thesis report presents the designs of compact planar ultra-wideband (UWB) antennas for wireless devices applications. Three main designs of UWB antennas are studied, namely, single UWB antennas, UWB multiple-input-multiple-out(MIMO)antennas, and transparent UWB antennas on the screens of mobile phones.
For single UWB antennas, the designs of two compact planar monopole antennas with compact sizes of 26×28 mm2and 30×39.3mm2are presented. The UWB operations of the antennas are achieved using a ground slot under the feed line, offsetting the feed line and the radiator from the middle of the ground plane and smoothly transforming the feed line. Simulation and measurement show that the two antennas can achieve an ultra-wide bandwidth with approximately omnidirectional patterns. A deep notch-band in5.1-5.85 GHz is created in one of the UWB antennas by employing two pairs of meander lines (MLs), one pair being close to the feed line and the other pair along the upper edge of the ground plane. At the notch frequency, the simulated efficiency is only 4%.
Three compact UWB-MIMO antennas with very compact sizes of 26×40 〖mm〗^2, 21×38 〖mm〗^2, and 22×36 〖mm〗^2 are designed. Each of them is designed using two UWB antenna elements perpendicularly or symmetrically placed. Different techniques such as using ground stubs besides the radiators, cutting inclined slots on the ground, and adding a T-shaped protruding from ground are proposed to lower mutual coupling between the two antenna elements. One of the antennas is designed to generate a notched band in 5.15-5.85 GHz using two ground strips. Simulation and measurement results show that these antennas can cover the entire UWB of 3.1-10.6GHz with mutual coupling of less than -15 dB, and envelope correlation coefficient of less than 0.1.
An UWB antenna is designed using a transparent conductive film for applications on mobile phone screens. The effects of a finger touching the screen are studied. Results show that, with the radiator on the bottom side of the screen and a thin film with a thickness of 0.05 mm on the top side to separate the finger and the antenna, the effects of the finger can be minimized.
In measurement of monopole antennas with small ground planes, due to the feeding cable used, there are always discrepancies between the simulated and measured results in radiation patterns, efficiencies, and gains at lower frequencies. To verify that the discrepancies in the results of these studies are indeed due to the feeding cable used in measurement, the models of the feeding cables are developed and used for simulation. Results show that, by using the cable model, the simulated and measured results in radiation patterns, efficiencies, and gains agree very well.published_or_final_version
Electrical and Electronic Engineering
Doctoral
Doctor of Philosophy
19
Bowden, Sarah L. "Application of mobile IT in construction." Thesis, Loughborough University, 2005. https://dspace.lboro.ac.uk/2134/794.
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In recent years, the construction industry has been compelled to explore all possible options for improving the delivery of their products and services. Clients are now expecting a better service and projects that meet their requirements more closely. This has challenged the industry to become more efficient, integrated and more attractive, with benefits for its potential workforce and for society as a whole. Information and communication technologies (ICT) are an enabler to facilitate the improvements required for modernisation. However, due to the geographically dispersed and nomadic nature of the construction industry's workforce, many people are prevented from efficiently and effectively using the ICT tools adopted to date. Mobile technologies providing the 'last mile' connection to the point-of activity could be the missing link to help address the ongoing drive for process improvement. Although this has been a well-researched area, several barriers to mainstream adoption still exist: including a perceived lack of suitable devices; a perceived lack of computer literacy; and the perceived high cost. Through extensive industry involvement, this research has taken the theoretical idea that mobile IT use in the construction industry would be beneficial, a step further; demonstrating by means of a state of the art assessment, usability trials, case studies and demonstration projects that the barriers to mainstream adoption can be overcome. The findings of this work have been presented in four peer-reviewed papers. An ongoing dissemination programme is expected to encourage further adoption.
20
Mony, Madeleine. "Reprogrammable optical phase array." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103276.
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The evolving needs of network carriers are changing the design of optical networks. In order to reduce cost, latency, and power consumption, electrical switches are being replaced with optical switching fabrics at the core of the networks. An example of such a network is an Agile All-Photonic Network (AAPN).This thesis presents a novel device that was designed to operate as an optical switch within the context of an AAPN network. The device is a Reprogrammable Optical Phase Array (ROPA), and the design consists of applying multiple electric fields of different magnitudes across an electro-optic material in order to create a diffractive optical element. The configuration of the electric fields can change to modify the properties of the diffractive device.
Such a device has a wide range of potential applications, and two different ROPA designs are presented. Both designs are optimized to function as 1xN optical switches. The switches are wavelength tunable and have switching times on the order of microseconds. The ROPA devices consist of two parts: a bulk electro-optic crystal, and a high-voltage CMOS chip for the electrical control of the device. The design, simulation, fabrication and testing of both the electrical and optical components of the devices are presented.
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Park, Jin-Woo. "Core lamination technology for micromachined power inductive components." Diss., Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-06072004-131319/unrestricted/park%5Fjin-woo%5F200405%5Fphd.pdf.
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Huang, Hong. "Hybrid and resilient WDM mesh optical networks." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/15751.
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Tan, Junyi, and 譚軍毅. "Investigation of novel liquid desiccant cooling system." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42664251.
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Sun, Yiye, and 孫憶業. "Design of UWB and multiple-band monopole antennas for body-centric wireless communications." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/207208.
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This thesis presents the designs of Ultra-wideband (UWB) monopole antennas, textile monopole antennas and transparent UWB textile antennas using planar technology for body-centric wireless communications (BCWC).
A planar antenna designed using offset-fed and slotted ground plane to extend the operating bandwidth for the industrial, scientific and medical (ISM)band and UWB is proposed. Results show that the antenna can achieve a bandwidth from 2.38 to 14.5 GHz with omni-directional radiation patterns in the E-plane. Agroup of nine planar UWB monopole antennas using different radiator shapes such as triangle, rectangle, square, annual ring, circle, horizontal ellipse, vertical ellipse, pentagon and hexagon for BCWC is studied using computer simulation and measurement. Results show that the monopole antenna having a vertical-elliptical-shape radiator has a relatively better performance than other monopole antennas.
Three textile antennas fabricated on fabric materials are studied. The first design is a triple-band textile antenna for wireless-local-area network (WLAN) and worldwide interoperability for microwave access (WiMAX) wireless communication applications. The radiator is composed of two branches and a short stub to generate the resonances at about 2.45, 3.5 and 5.5 GHz, respectively. Simulated and measured results show that the three frequency bands can be set independently. The second design is an UWB antenna consisting of a circular radiator, a tapered feed line and a slotted ground plane. Results show that the antenna can achieve a bandwidth of 3 to 12 GHz. The third design is a compact belt-loop UWB antenna with microstrip-fed. The antenna has a simple elliptical-shaped radiator, a three-step staircase on both sides of the feed line and a slot on the ground plane. It has a very compactsize of 11×40=440 mm2and can still achieve a bandwidth of 3.1 to 12.8 GHz. To emulate the on-body conditions, the two UWB antennas are studied in the bending and crumpling conditions due to the curvature of human body. Results show that both UWB textile antennas have quite stable performances throughout the UWB band.
The two UWB textile antennas are re-designed using a transparent conductive film (TCF)as the radiator and ground plane on fabric substrate. Results show that the measured reflection coefficients of transparent antennas agree well with the simulated results. However, the measured radiation patterns have large discrepancies with the simulated results, which are mainly due to the uncertain electric properties of TCF in radio frequency. Results show that the antennas have a better performance, in terms ofbandwidth, peak gain and radiation efficiency ,than those of other transparent antennas studied before, making our proposed antennas suitable for body-centric wireless communications.published_or_final_version
Electrical and Electronic Engineering
Doctoral
Doctor of Philosophy
25
Zaerr, Jon Benjamin 1963. "Development and evaluation of a dynamic phantom using four independently perfused in vitro kidneys as a tool for investigating hyperthermia systems." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/291341.
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A dynamic phantom for use in investigating hyperthermia heating systems has been designed, constructed, and tested. A computer controlled the flow rate of 80% Ethanol to each of 4 preserved in vitro canine kidneys which acted as the phantom material. The flow rates were regulated with stepper motor controlled valves and measured with flow meters by the computer. This provided a flexible system for adjusting the perfusion as desired. The system was tested with step and ramp changes in perfusion under constant power ultrasound and with a temperature controlled perfusion algorithm, all of which yielded repeatable results. The dynamic phantom developed in this work shows potential for expediting investigations of hyperthermia controllers, temporal blood flow patterns, and inverse problems. Its computer based nature gives it great flexibility which would lend itself well to automated testing procedures.
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Chang, Jae Joon. "CMOS differential analog optical receivers with hybrid integrated I-MSM detector." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/14998.
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Imam, Neena. "Analysis, design, and testing of semiconductor intersubband devices." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/15664.
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Ramukhubathi, Collin. "A business plan for launching a material handling company - HELM solutions." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/96202.
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Thesis (MBA)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Mobile lifter (ML) is a product that is used to lift loads or materials ranging from 20–600 kilograms (kg), and to move the loads to anywhere within the factory up to a height of 2.3 metres (m). The ML is ideal for loads heavier than human comfort, dangerous to touch by hands, requiring repetitive moving and not heavy enough for a forklift. As the need for labour rises and manufactures want to increase productivity, the ML becomes the solution. Currently, there is no company that specialises in ML, and that provides good service to the customers. HELM intends filling that gap in the markets. HELM plans to acquire exclusive distribution rights with a European base supplier of MLs. HELM will become the distributor of MLs in Southern Africa. HELM will have its base or office in Cape Town (CT), but also secure subcontractors in three other provinces, namely Gauteng, KwaZulu- Natal (KZN), and the Eastern Cape (EC). HELM will sell products from its supplier partner and it will offer services and a maintenance plan to its clients at a competitive rate. The ML can be used in manufacturing, wholesale, the retail trade and motor trade, and transport and storage. The three sectors account for over 35 percent of South Africa’s gross domestic product. The manufacturing sector is the largest sector with many industries. The most attractive industries are the fast moving consumer goods, automotive, pharmaceutical and chemical manufacturing industries. Although the industry or market is fragmented, Gauteng has the largest target market with over 9000 registered manufacturing enterprise. It is followed by KwaZulu-Natal, then the Western Cape and finally the Eastern Cape. The ML industry is still in its infancy, and HELM Solutions intend to sell 25 units in the first year, 33 in the second and then 36 in the third year. The current distributors of MLs only have one point of service per distributor in South Africa and MLs are non-core products for them. HELM also intends differentiating itself from other distributors by being a solution provider to clients, and not a product distributor. HELM wants to understand the clients’ business, understand their needs, and provide them with solution that will also increase their profit. This should give HELM a competitive advantage and make it difficult for clients to substitute the HELM products and service. Franck Tshilombo is one of the three entrepreneurs who will be directly involved in the business. He will start as the only employee of the business. He has been working with MLs for the past four years. His experience ranges from selling and marketing to ordering, assembling, service and maintenance of MLs. Kevin French brings experience in the financial field of investments. He holds a B Com degree and is a CFA charter holder. He has 25 years combined experience in financial services at large corporates and smaller entrepreneurial start-ups. He owns an investment management business and two paint distribution businesses. His experience includes starting new businesses, takeovers and turnarounds in financial services, and construction and electrical engineering. Collin Ramukhubathi who has a mechanical engineering degree and is an MBA candidate, has 15 years working experience in general management in construction and the mining sector. HELM Solutions require funding for fixed assets and working capital. The fixed asset will be funded by shareholders in the form of assets worth R30 000 and cash of R15 000. The amount of external funding required is R154 000. The desired funding should be in the form of an overdraft loan, as not all the funds will be needed in the beginning. This funding will be used towards the monthly expenses for the period of three months and towards increases in sales within the first five months. The funds will be needed during sales growth as the cash conversion cycle of the business is long. The overdraft loan is based on the interest rate of 12 percent. Based on these estimates, the loan will be fully repaid within 11 months.
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Fitzgerald, Nicholas B. "The Small Volume Autonomous Water Sampler (SVAWS): An Innovative, Cost- Effective, Adaptable Protocol." PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/1533.
Full textAbstract:
As of 2007, U.S. pesticide use stood at 1.1 billion pounds with 80% of all usage in agriculture. Such realities pose a potentially dangerous threat to our surface water bodies. This research provides a detailed analysis of the design, operation and field testing of a prototype water sampler, the Small Volume Autonomous Water Sampler (SVAWS). The research includes a discussion of the design and construction of the SVAWS. Seven USGS employees operated the SVAWS in a number of different states and conditions in order to collect samples for pesticide analysis. Field-testing outcomes of the SVAWS were measured through a Participant Survey Request and a Likert-Scale Assessment.
Overall, survey data proved the SVAWS to be an effective device for collecting water samples in different locations and conditions. Users also understood the SVAWS has significant potential for applications other than pesticide studies. While feedback did show a number of alterations or modifications could improve the design, the device proved to be effective across many of its goals, from valid water sampling to reducing costs of sample acquisition. Recommendations for future research include these and other avenues of research. A conclusion addresses the potential future of the SVAWS with respect to water sampling applications.
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Peterson, Zachariah Marcus. "Physical and Electrical Characterization of Triethanolamine Based Sensors for NO₂ Detection and the Influence of Humidity on Sensing Response." PDXScholar, 2011. https://pdxscholar.library.pdx.edu/open_access_etds/418.
Full textAbstract:
Triethanolamine (TEA) is a semiconducting polymer which exhibits a resistance change when exposed to various gases. The polymer also exhibits a number of reactions with nitrogen dioxide, with the reaction products being heavily dependent on the presence or absence of water vapor. Previous studies have attempted the incorporation of a TEA-carbon nanoparticle composite as the active sensing layer in a chemresistive sensor for detection of NO₂. The incorporation of carbon nanoparticles in the polymer nanocomposite was thought to amplify the sensor's response. There are a number of chemical reactions that can occur between TEA and NO₂, with the reaction products being heavily dependent on the presence and amount of water vapor in the environment. Because of this influence, it becomes necessary to know to what degree the presence of water vapor interferes with the sensing response. In this work we show that the sensor exhibits a reversible resistance change as background humidity changes. This sensitivity to humidity changes is so large that it renders undetectable any resistance change that could be caused by the reaction of TEA with NO₂. Furthermore, we show that the presence of low levels of NO₂ do not interfere with adsorption of water vapor. The detection mechanism is based on measuring resistance changes in the TEA film due to the adsorption/desorption of water vapor. The sensing response can be described by Langmuir adsorption by using a site-based model for the polymer film resistance. Breakdown of the polymer film over time due to continuous adsorption of water vapor, as well as photodegradation of the polymer film, will be discussed. SEM images will also be presented showing growth of crystallites on the electrode walls, as well as experimental results demonstrating degradation of the sensing film during sensor operation.
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Dody, Joseph W. "Study of biomass combustion characteristics for the development of a catalytic combustor/gasifier." Thesis, Virginia Tech, 1985. http://hdl.handle.net/10919/43039.
Full textAbstract:
The research reported here explored, a "new" approach to biomass
energy conversion for small-scale process heat-applications. The conversion process uses close-coupled catalytic. combustion to burn combustibles in effluent generated by primary combustion or gasification of biomass fuels. Computer control of primary and secondary air flow rates allow control of the devices output power while maintaining fuel-lean or stoichiometric conditions in the effluent entering the catalytic combustion zone. The intent of the secondary combustion system is to ensure "clean" exhaust (i.e., promote complete combustion).
A small-scale combustor/gasifier was built and instrumented.
Characteristics of combustion were studied for three biomass fuels so
that primary and secondary air flow control strategies could be devised. A bang-bang type controller was devised for primary air flow
control. Secondary air as controlled based on feedback signals from an inexpensive automobile exhaust gas oxygen sensor. The control strategies and catalytic combustion were implemented on prototype combustor/gasifier and the device was tested with good results.
Power turn down ratios of 4 to 1 and 3 to 1 were achieved. The
zitconia-type automobile exhaust gas oxygen sensors adapted well to the combustion environment of biomass fuel, at least for short periods (long term durability tests were not conducted). The secondary air control system was able to maintain fuel-lean flows for the most part and, the secondary combustion system provided reductions of approximately three fourths in carbon monoxide emissions.Master of Science
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Deo, Nitin. "Completion and validation of the design of a reconfigurable image processing board." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/53064.
Full textAbstract:
Starting in September 1984, the Telesign project is an extensive and complex project proposed and undertaken by Dr. Nadler at Virginia Tech. The emphasis of this project is to enable the members of the deaf community to communicate visually using sign language or lip reading over the telephone network.
The Image Processing Board (IPB) is the 'Brain' of the whole system. The IPB processes a given frame of an image to transmit only selected data. It uses the pseudo-laplacian operator, invented by Dr. Nadler, for edge detection. According to a recent survey of various edge detection algorithms by D. E. Pearson, [1], the pseudo-laplacian operator is the most efficient one and it produces the most natural pictures.
The whole IPB hosts about one hundred LSI/VLSI chips according to the present hardware description. In the case of such a big system, hardware simulation becomes mandatory in order to ensure reliability of the design and to anticipate any kind of logic or timing errors in the design. This thesis describes the modifications to the original design to make it reconfigurable with proper initialization and the Hardware Simulation of the IPB, using General Simulation Program (GSP), including some comments on the simulators available at Virginia Tech and in particular a critique of the simulator used here. Many improvements to the simulator are suggested. Precautions to be taken while preparing the lay-out and wiring of the IPB, suggestions to simplify the design at some points at the cost of a few more chips, and lastly the instructions to run the models to get the required results, are outlined in this thesis.Master of Science
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Xing, Chengwen, and 邢成文. "Linear minimum mean-square-error transceiver design for amplify-and-forward multiple antenna relaying systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B44769738.
Full text
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Mach, Phillip M. "Design Considerations and Implementation of Portable Mass Spectrometers for Environmental Applications." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc984177/.
Full textAbstract:
Portable mass spectrometers provide a unique opportunity to obtain in situ measurements. This minimizes need for sample collection or in laboratory analysis. Membrane Inlet Mass Spectrometry (MIMS) utilizing a semi permeable membrane for selective rapid introduction for analysis. Polydimethylsiloxane membranes have been proven to be robust in selecting for aromatic chemistries. Advances in front end design have allowed for increased sensitivity, rapid sample analysis, and on line measurements. Applications of the membrane inlet technique have been applied to environmental detection of clandestine drug chemistries and pollutants. Emplacement of a mass spectrometer unit in a vehicle has allowed for large areas to be mapped, obtaining a rapid snapshot of the various concentrations and types of environmental pollutants present. Further refinements and miniaturization have allowed for a backpackable system for analysis in remote harsh environments. Inclusion of atmospheric dispersion modeling has yielded an analytical method of approximating upwind source locations, which has law enforcement, military, and environmental applications. The atmospheric dispersion theories have further been applied to an earth based separation, whereby chemical properties are used to approximate atmospheric mobility, and chemistries are further identified has a portable mass spectrometer is traversed closer to a point source.
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Shelton, Debra Kay. "A selection model for automated guided vehicles." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/101465.
Full textAbstract:
This research identifies the attributes to be considered in the selection of an automated guided vehicle (AGV). A distinction is made between automated guided vehicles (AGVs) and an automated guided vehicle system (AGVS). This research is concerned only with the selection of automated guided vehicles (AGVs).
A selection model is developed which forces the user to evaluate attributes. his requirements and preferences for AGV The first step of the model allows the user to enter his specifications for AGV attributes which are applicable to his production environment. The second step in the selection model is for the user to determine 8-15 attributes to use as selection criteria. In the third phase, the user inputs his preferences and priorities with respect to the attributes chosen as selection criteria in the second step. model ranks the Based on this information, the selection AGV models in the feasible set. A description of the model and a numerical example are included.
Steps 1 and 2, described above, are implemented using an R:BASE™ program. The BASIC computer language was used to perform the interrogation of the user with respect to his priorities and preferences among attributes in Step 3. The IBM PC™ is the hardware chosen for running the selection model.M.S.
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Pietersen, Richard Gordon. "Thermoelectric cooling for microwave transmitters located at remote sites." Thesis, Cape Technikon, 1992. http://hdl.handle.net/20.500.11838/2158.
Full textAbstract:
Thesis (MDiploma (Mechanical Engineering))--Cape Technikon, 1992.An investigation into the use of thermoelectric cooling energised by photovoltaic (PV) panels for removing sensible heat from electronic telecommunications equipment. The thermoelectric cooler consists of a solid-state heat pump which operates on the principle of the Peltier effect. The thermoelectric device transfers heat through a cold sink to ambient outside air via a hot sink. A major prerequisite was that the system should be selfsufficient in terms of power because the sites for the microwave transmitters are often remote. Solar power was the only alternative source of energy and the cooler was designed to accept direct current from PV panels which are usually used to power transmitters on distant locations. The cooling device had to be reliable, virtually maintenance-free and simple to repair.
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Gurganus, Heath Alan. "Battery Energy Storage Systems to Mitigate the Variability of Photovoltaic Power Generation." PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/1495.
Full textAbstract:
Methods of generating renewable energy such as through solar photovoltaic (PV) cells and wind turbines offer great promise in terms of a reduced carbon footprint and overall impact on the environment. However, these methods also share the attribute of being highly stochastic, meaning they are variable in such a way that is difficult to forecast with sufficient accuracy. While solar power currently constitutes a small amount of generating potential in most regions, the cost of photovoltaics continues to decline and a trend has emerged to build larger PV plants than was once feasible. This has brought the matter of increased variability to the forefront of research in the industry. Energy storage has been proposed as a means of mitigating this increased variability -- and thus reducing the need to utilize traditional spinning reserves -- as well as offering auxiliary grid services such as peak-shifting and frequency control. This thesis addresses the feasibility of using electrochemical storage methods (i.e. batteries) to decrease the ramp rates of PV power plants. By building a simulation of a grid-connected PV array and a typical Battery Energy Storage System (BESS) in the NetLogo simulation environment, I have created a parameterized tool that can be tailored to describe almost any potential PV setup. This thesis describes the design and function of this model, and makes a case for the accuracy of its measurements by comparing its simulated output to that of well-documented real world sites. Finally, a set of recommendations for the design and operational parameters of such a system are then put forth based on the results of several experiments performed using this model.
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Hillig, Mark Alexander. "Automated Channel Assessment for Single Chip MedRadio Transceivers." PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/1005.
Full textAbstract:
Modern implantable and body worn medical devices leverage wireless telemetry to improve patient experience and expand therapeutic options. Wireless medical devices are subject to a unique set of regulations in which monitoring of the available frequency spectrum is a requirement. To this end, implants use software protocols to assess the in-band activity to determine which channel should be used. These software protocols take valuable processing time and possibly degrade the operational lifetime of the battery. Implantable medical devices often take advantage of a single chip transceiver as the physical layer for wireless communications. Embedding the channel assessment task in the transceiver hardware would free the limited resources of the microprocessor. This thesis proposes hardware modifications to existing transceiver architectures which would provide an automated channel assessment means for implantable medical devices. The results are applicable beyond medical device applications and could be employed to benefit any low-power, wireless, battery-operated equipment.
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Kwiatkowski, Terese Marie. "The miniature electrical cone penetrometer and data acquisition system." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/90934.
Full textAbstract:
The static cone penetrometer is an in-situ testing tool which was originally developed to derive information on soil type and soil strength. More recently, it has found application in liquefaction assessment. Typical cone penetrometers are heavy duty devices which are operated with the assistance of a drill rig. However, this capacity is not necessary in the case of field studies of liquefaction, since liquefaction usually occurs at relatively shallow depths. This thesis is directed to the goal of the development of a miniature, lightweight cone penetrometer which can be used in earthquake reconnaissance studies related to liquefaction problems.
The research for this thesis involved four principal objectives:
1. Development of procedures to automatically acquire and process measurements from a miniature electrical cone;
2. Develop and perform tests in a model soil-filled bin to calibrate the cone;
3. Evaluate the utility and accuracy of the cone results as a means to assess conventional soil properties; and,
4. Conduct a preliminary evaluation of the cone results in the context of recently developed methods to predict liquefaction potential.
The work in regard to the first objective involved assembling and writing software for a microcomputer based data acquisition system. Successful implementation of this system allowed data from the tests to be rapidly processed and displayed. Calibration tests with the cone were carried out in a four foot high model bin which was filled ten times with sand formed to variety of densities. The sand used is Monterey No. 0/30, a standard material with well known behavioral characteristics under static and dynamic loading.
The test results showed the cone to produce consistent data, and to be able to readily distinguish the varying density configurations of the sand. Using the results in conventional methods for converting cone data into soil parameters yielded values which were consistent with those expected. Liquefaction potential predictions were less satisfying, although not unreasonable. Further research is needed in this area both to check the reliability of the prediction procedures and the ability to achieve the desired objectives.M.S.
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Thakare, Aditya. "A Study of Microwave curing of Underfill using Open and Closed microwave ovens." PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2246.
Full textAbstract:
As the demand for microprocessors is increasing with more and more consumers using integrated circuits in their daily life, the demand on the industry is increasing to ramp up production.
In order to speed up the manufacturing processes, new and novel approaches are trying to change certain aspects of it. Microwaves have been tried as an alternative to conventional ovens in the curing of the polymers used as underfills and encapsulants in integrated circuits packages. Microwaves however being electromagnetic waves have non uniform energy distribution in different settings, causing burning or incomplete cure of polymers.
In this study, we compare the two main types of microwaves proposed to perform the task of curing the polymers. To limit the study and obtain comparable results, both microwaves were limited to propagate in a single mode, TE10. The first is a closed microwave cavity using air as the propagation medium, and the second is an open microwave oven with a PTFE cavity that uses an evanescent field to provide energy.
The open air cavity was studied with different orientations of a substrate placed inside it so as to find the best case scenario in the curing process. This scenario was then compared with the best case scenario found for a sample cured in an evanescent field.
This comparison yielded results showing an advantage of the open microwave in maximum field present, thus leading to higher localized energy absorption and temperatures in the substrate, however this case also lead to a higher temperature gradient. The substrate cured in the closed microwave has a lower temperature gradient, but also a lower maximum field which leads to slower cure.
In the TE10 mode therefore, a closed microwave has an overall advantage as the heating process is only slightly slower than that of an open cavity, but the temperature gradient in this case is significantly lower.
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Enriquez, Vivanco Jaime Gabriel Jesús, and Giagun Kioshi Alberto Shimabukuro. "Diseño de mezcla de concreto f’cr 210 kg/cm2 mediante la adición de vidrio molido reciclado en reemplazo parcial de cemento tipo I en Lima-Perú." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2019. http://hdl.handle.net/10757/628155.
Full textAbstract:
Este proyecto tiene la finalidad de informar al lector sobre una forma en que el vidrio desaprovechado puede ser empleado en el sector construcción brindando beneficios para la ingeniería civil. Esta investigación se lleva a cabo utilizando vidrio molido reciclado como adición al concreto y logrando un diseño de mezcla con una resistencia requerida a la compresión de 210 kg/cm2 a los 28 días de curado y un asentamiento de 3 - 4 pulgadas.
Para averiguar las ventajas de utilizar vidrio molido reciclado como adición al concreto, es necesario hacer una comparación entre un concreto patrón y los adicionados con polvo de vidrio. Se plantearon tres tipos de concreto con diferentes dosis de sustitución parcial de cemento Tipo I por polvo de vidrio, estas son 0%, 10% y 20%. Se realizaron múltiples diseños de mezcla hasta llegar a los diseños finales, los cuales cumplen con un asentamiento de 3 a 4 pulgadas y un f’cr de 210 kg/cm2 a los 28 días. Luego, se realiza un análisis de precios unitarios para los diseños finales y se procede a la comparación de estos.
Finalmente, los resultados muestran que el concreto con 20% de sustitución tiene un costo de producción menor que el resto. Otro resultado importante es que, a más vidrio adicionado en el concreto, menor es su resistencia a edades tempranas. En resumen, al reemplazar el 20% del cemento por polvo de vidrio se puede obtener un beneficio económico.This project aims to inform the reader about a way in which wasted glass can be used in the construction sector providing benefits for civil engineering. This investigation is carried out using recycled ground glass as an addition to concrete and achieving a mix design with a required compressive strength of 210 kg / cm2 after 28 days of curing and a 3-4 inch slump. To find out the advantages of using recycled ground glass as an addition to concrete, it is necessary to make a comparison between a standard concrete and those added with glass powder. Three types of concrete were proposed with different doses of partial replacement of Type I cement with glass dust, these are 0%, 10% and 20%. Multiple mixing designs were made until reaching the final designs, which comply with a 3 to 4 inch slump and a f’cr of 210 kg / cm2 at 28 days. Then, a unit price analysis for the final designs is carried out and these are compared. Finally, the results show that concrete with 20% replacement has a lower production cost than the rest. Another important result is that, the more glass added to the concrete, the lower its resistance at an early age. In summary, by replacing 20% of the cement with glass dust, an economic benefit can be obtained.
Tesis
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Brinkman, Karen L. "Design of a microcomputer-based open heart surgery patient monitor." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/76031.
Full textAbstract:
A patient monitor device for use during open heart surgery has been designed and constructed. The device uses a VIC 20 microcomputer along with some additional circuitry to monitor 3 separate functions. The first patient variable monitored is the blood flow rate through the extracorporeal blood circuit during surgery. The device also continuously monitors and displays 6 separate temperatures. Finally, 3 individual timers are monitored and displayed with the device. Both the hardware and the software used in the design are fully described.Master of Science
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Greif, Steffi. "Ökonomische Analyse der Rückgewinnung von hochwertigen Metallen aus elektrischen und elektronischen Altgeräten in Deutschland." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1243336773453-61654.
Full textAbstract:
Die vorliegende Ausgabe beschäftigt sich mit dem Thema „Ökonomische Analyse der Rückgewinnung von hochwertigen Metallen aus elektrischen und elektronischen Altgeräten in Deutschland“. Elektro- und Elektronikgeräte sind aus dem täglichen Leben nicht mehr wegzudenken; die Unternehmen entwickeln und produzieren immer leistungsfähigere Produkte, wobei durch die immer schnelleren und kurzlebigeren Innovationszyklen die Abfallberge ausgedienter Elektro(nik)geräte beständig wachsen. Mit Inkrafttreten des Elektro- und Elektronikgerätegesetz am 24. März 2005 werden alte Elektro(nik)geräte zukünftig getrennt gesammelt und weitgehend verwertet. Neu ist, dass die Hersteller mehr Verantwortung für ihre Produkte übernehmen und zur Verwertung der getrennt gesammelten Elektro- und Elektronik-Altgeräten verpflichtet sind. Das Elektro- und Elektronikgerätegesetz geht zum einen aus der europäischen Richtlinie über die Entsorgung von Elektro- und Elektronik-Altgeräten (WEEE) und zum anderen aus der europäischen Richtlinie über die Verwendung bestimmter gefährlicher Stoffe in Elektro- und Elektronikgeräten (RoHS) hervor und gilt als Reaktion auf die wachsenden Elektro(nik)schrott-Berge. Für die Unternehmen der Entsorgungs- und Recyclingbranche ergeben sich mit diesen gesetzlichen Neuerungen neue Chancen auf Weiterentwicklung ihres Geschäftsfeldes. Besonderes Augenmerk gilt den Demontageunternehmen, mit deren Hilfe erst die gesetzlichen Forderungen, hinsichtlich der zu erzielenden Rückgewinnungsquoten und der notwendigen selektiven Behandlung einiger Baugruppen, erfüllt werden können. Die Rückgewinnung hochwertiger Metalle aus Elektro(nik)schrott bedarf im Hinblick der Preissteigerungen auf den Rohstoffmärkten höchster Priorität. Mit Etablierung eines Sekundärrohstoffmarktes kann ein rohstoffarmes Land wie Deutschland der Abhängigkeit des Importes von Primärrohstoffen signifikant entgegenwirken.
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Zimmerman, Nicole P. "Time-Variant Load Models of Electric Vehicle Chargers." PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2297.
Full textAbstract:
In power distribution system planning, it is essential to understand the impacts that electric vehicles (EVs), and the non-linear, time-variant loading profiles associated with their charging units, may have on power distribution networks. This research presents a design methodology for the creation of both analytical and behavioral models for EV charging units within a VHDL-AMS simulation environment.
Voltage and current data collected from Electric Avenue, located on the Portland State University campus, were used to create harmonic profiles of the EV charging units at the site. From these profiles, generalized models for both single-phase (Level 2) and three-phase (Level 3) EV chargers were created. Further, these models were validated within a larger system context utilizing the IEEE 13-bus distribution test feeder system.
Results from the model's validation are presented for various charger and power system configurations. Finally, an online tool that was created for use by distribution system designers is presented. This tool can aid designers in assessing the impacts that EV chargers have on electrical assets, and assist with the appropriate selection of transformers, conductor ampacities, and protection equipment & settings.
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Rodriguez-Anderson, Santiago Martin. "Sensible Air to Air Heat Recovery Strategies in a Passive House." PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2123.
Full textAbstract:
Due to rising energy costs and concerns about global climate change, high performance buildings are more in demand than ever before. With roughly 20% of the total energy consumption in the United States being devoted to residential use, this sector represents a significant opportunity for future savings. There are many guidelines and standards for reducing building energy consumption. One of the most stringent is the Passive House Standard. The standard requires that that air infiltration is less than or equal to 0.6 air changes per hour at a 50 Pascal pressure difference (ACH 50), annual heating energy is less than or equal to 15kWh/m2, and total annual source energy is less than or equal to 120 kWh/m2. For comparison, the typical West coast US residence has an ACH50 of 5 and annually uses more than 174 kWh/m2 of source energy according to the 2009 Residential Energy Consumption Survey. With these challenging requirements, successful implementation of the Passive House Standard requires effective strategies to substantially reduce energy consumption for all end uses.
Heating and cooling loads are low by necessity in a Passive House. As such this makes end uses like water heating a much larger fraction of total energy use than they would be in a typical building. When air to water heat pumps are employed the energy consumption by water heating is lowered significantly. By employing innovative heat recovery strategies the energy consumption for water heating and HVAC can be reduced even further. This study uses energy modeling and project cost analysis to evaluate three innovative control strategies. Results for a Passive House in Portland Oregon show a savings of about $70 annually with a payback period of 10 years. The same Passive House in Fairbanks Alaska with a different strategy would save $150 annually with a payback period of 5 years.
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Sáček, Petr. "Analýza a řízení rizik technologických etap výstavby zděných konstrukcí." Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-240997.
Full textAbstract:
This thesis deals with the analysis and evaluation of quality, environmental, and security risks, hazards and application of appropriate methodology to a particular construction project. For an application is selected the key construction technology - walling. Diploma thesis establishes a framework for risk management on the basis of established integrated management system (IMS) defines the objectives and mechanisms in controlling adherence to standards, evaluation of business risks, defining risk management strategies, the draft risk management procedures, monitoring their functioning, assessing their performance and any improvement and support the process of supplying the required information.
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Riddell, Kevin Donald Alexander. "Design, testing and demonstration of a small unmanned aircraft system (SUAS) and payload for measuring wind speed and particulate matter in the atmospheric boundary layer." Thesis, Arts and Science, 2014. http://hdl.handle.net/10133/3416.
Full textAbstract:
The atmospheric boundary layer (ABL) is the layer of air directly influenced by the Earth’s surface and is the layer of the atmosphere most important to humans as this is the air we live in. Methods for measuring the properties of the ABL include three general approaches: satellite-based, ground- based and airborne. A major research challenge is that many contemporary methods provide a restricted spatial resolution or coverage of variations of ABL properties such as how wind speed varies across a landscape with complex topography. To enhance our capacity to measure the properties of the ABL, this thesis presents a new technique that involves a small unmanned aircraft system (sUAS) equipped with a customized payload for measuring wind speed and particulate matter. The research presented herein outlines two key phases in establishing the proof-of-concept of the payload and its integration on the sUAS: (1) design and testing and (2) field demonstration. The first project focuses on measuring wind speed, which has been measured with fixed wing sUASs in previous research, but not with a helicopter sUAS. The second project focuses on the measurement of particulate matter, which is a major air pollutant typically measured with ground- based sensors. Results from both proof-of-concept projects suggest that ABL research could benefit from the proposed techniques.
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Jůn, Michal. "Výrobní areál LIWA v Pelhřimově - příprava realizace a řízení stavby." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265436.
Full textAbstract:
The aim of the thesis is the process of building technological project LIWA manufacturing facility in Pelhřimov. It deals mainly a technological process for the realization of the main building. The thesis contains a technical report, technological specification, control and test plan. Other parts of the work are time and financial plan, machine and mechanic design, project about equipment of construction site and time schedule. The annexes are further addressed drawings of the building site equipment.
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Fenollosa, Artés Felip. "Contribució a l'estudi de la impressió 3D per a la fabricació de models per facilitar l'assaig d'operacions quirúrgiques de tumors." Doctoral thesis, Universitat Politècnica de Catalunya, 2019. http://hdl.handle.net/10803/667421.
Full textAbstract:
La present tesi doctoral s’ha centrat en el repte d’aconseguir, mitjançant Fabricació Additiva (FA), models per a assaig quirúrgic, sota la premissa que els equips per fer-los haurien de ser accessibles a l’àmbit hospitalari. L’objectiu és facilitar l’extensió de l’ús dels prototips com a eina de preparació d’operacions quirúrgiques, transformant la pràctica mèdica actual de la mateixa manera que en el seu moment ho van fer tecnologies com les que van facilitar l’ús de radiografies. El motiu d’utilitzar FA, en lloc de tecnologies més tradicionals, és la seva capacitat de materialitzar de forma directa les dades digitals obtingudes de l’anatomia del pacient mitjançant sistemes d’escanejat tridimensional, fent possible l’obtenció de models personalitzats. Els resultats es centren en la generació de nou coneixement sobre com aconseguir equipaments d’impressió 3D multimaterials accessibles que permetin l’obtenció de models mimètics respecte als teixits vius. Per facilitar aquesta buscada extensió de la tecnologia, s’ha focalitzat en les tecnologies de codi obert com la Fabricació per Filament Fos (FFF) i similars basades en líquids catalitzables. La recerca s’alinea dins l’activitat de desenvolupament de la FA al CIM UPC, i en aquest àmbit concret amb la col·laboració amb l’Hospital Sant Joan de Déu de Barcelona (HSJD). El primer bloc de la tesi inclou la descripció de l’estat de l’art, detallant les tecnologies existents i la seva aplicació a l’entorn mèdic. S’han establert per primer cop unes bases de caracterització dels teixits vius -sobretot tous- per donar suport a la selecció de materials que els puguin mimetitzar en un procés de FA, a efectes de millorar l’experiència d’assaig dels cirurgians. El caràcter rígid dels materials majoritàriament usats en impressió 3D els fa poc útils per simular tumors i altres referències anatòmiques. De forma successiva, es tracten paràmetres com la densitat, la viscoelasticitat, la caracterització dels materials tous a la indústria, l’estudi del mòdul elàstic de teixits tous i vasos, la duresa d’aquests, i requeriments com l’esterilització dels models. El segon bloc comença explorant la impressió 3D mitjançant FFF. Es classifiquen les variants del procés des del punt de vista de la multimaterialitat, essencial per fer models d’assaig quirúrgic, diferenciant entre solucions multibroquet i de barreja al capçal. S’ha inclòs l’estudi de materials (filaments i líquids) que serien més útils per mimetitzar teixits tous. Es constata com en els líquids, en comparació amb els filaments, la complexitat del treball en processos de FA és més elevada, i es determinen formes d’imprimir materials molt tous. Per acabar, s’exposen sis casos reals de col·laboració amb l’HJSD, una selecció d’aquells en els que el doctorand ha intervingut en els darrers anys. L’origen es troba en la dificultat de l’abordatge d’operacions de resecció de tumors infantils com el neuroblastoma, i a la iniciativa del Dr. Lucas Krauel. Finalment, el Bloc 3 té per objecte explorar nombrosos conceptes (fins a 8), activitat completada al llarg dels darrers cinc anys amb el suport dels mitjans del CIM UPC i de l’activitat associada a treballs finals d’estudis d’estudiants de la UPC, arribant-se a materialitzar equipaments experimentals per validar-los. La recerca ampla i sistemàtica al respecte fa que s’estigui més a prop de disposar d’una solució d’impressió 3D multimaterial de sobretaula. Es determina que la millor via de progrés és la de disposar d’una pluralitat de capçals independents a fi de capacitar la impressora 3D per integrar diversos conceptes estudiats, materialitzant-se una possible solució. Cloent la tesi, es planteja com seria un equipament d’impressió 3D per a models d’assaig quirúrgic, a fi de servir de base per a futurs desenvolupaments.La presente tesis doctoral se ha centrado en el reto de conseguir, mediante Fabricación Aditiva (FA), modelos para ensayo quirúrgico, bajo la premisa que los equipos para obtenerlos tendrían que ser accesibles al ámbito hospitalario. El objetivo es facilitar la extensión del uso de modelos como herramienta de preparación de operaciones quirúrgicas, transformando la práctica médica actual de la misma manera que, en su momento, lo hicieron tecnologías como las que facilitaron el uso de radiografías. El motivo de utilizar FA, en lugar de tecnologías más tradicionales, es su capacidad de materializar de forma directa los datos digitales obtenidos de la anatomía del paciente mediante sistemas de escaneado tridimensional, haciendo posible la obtención de modelos personalizados. Los resultados se centran en la generación de nuevo conocimiento para conseguir equipamientos de impresión 3D multimateriales accesibles que permitan la obtención de modelos miméticos respecto a los tejidos vivos. Para facilitar la buscada extensión de la tecnología, se ha focalizado en las tecnologías de código abierto como la Fabricación por Hilo Fundido (FFF) y similares basadas en líquidos catalizables. Esta investigación se alinea dentro de la actividad de desarrollo de la FA en el CIM UPC, y en este ámbito concreto con la colaboración con el Hospital Sant Joan de Déu de Barcelona (HSJD). El primer bloque de la tesis incluye la descripción del estado del arte, detallando las tecnologías existentes y su aplicación al entorno médico. Se han establecido por primera vez unas bases de caracterización de los tejidos vivos – principalmente blandos – para dar apoyo a la selección de materiales que los puedan mimetizar en un proceso de FA, a efectos de mejorar la experiencia de ensayo de los cirujanos. El carácter rígido de los materiales mayoritariamente usados en impresión 3D los hace poco útiles para simular tumores y otras referencias anatómicas. De forma sucesiva, se tratan parámetros como la densidad, la viscoelasticidad, la caracterización de materiales blandos en la industria, el estudio del módulo elástico de tejidos blandos y vasos, la dureza de los mismos, y requerimientos como la esterilización de los modelos. El segundo bloque empieza explorando la impresión 3D mediante FFF. Se clasifican las variantes del proceso desde el punto de vista de la multimaterialidad, esencial para hacer modelos de ensayo quirúrgico, diferenciando entre soluciones multiboquilla y de mezcla en el cabezal. Se ha incluido el estudio de materiales (filamentos y líquidos) que serían más útiles para mimetizar tejidos blandos. Se constata como en los líquidos, en comparación con los filamentos, la complejidad del trabajo en procesos de FA es más elevada, y se determinan formas de imprimir materiales muy blandos. Para acabar, se exponen seis casos reales de colaboración con el HJSD, una selección de aquellos en los que el doctorando ha intervenido en los últimos años. El origen se encuentra en la dificultad del abordaje de operaciones de resección de tumores infantiles como el neuroblastoma, y en la iniciativa del Dr. Lucas Krauel. Finalmente, el Bloque 3 desarrolla numerosos conceptos (hasta 8), actividad completada a lo largo de los últimos cinco años con el apoyo de los medios del CIM UPC y de la actividad asociada a trabajos finales de estudios de estudiantes de la UPC, llegándose a materializar equipamientos experimentales para validarlos. La investigación amplia y sistemática al respecto hace que se esté más cerca de disponer de una solución de impresión 3D multimaterial de sobremesa. Se determina que la mejor vía de progreso es la de disponer de una pluralidad de cabezales independientes, a fin de capacitar la impresora 3D para integrar diversos conceptos estudiados, materializándose una posible solución. Para cerrar la tesis, se plantea cómo sería un equipamiento de impresión 3D para modelos de ensayo quirúrgico, a fin de servir de base para futuros desarrollos.
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Van, der Merwe Ryno. "Corrosion characteristics of steels and metallic alloys used as construction materials in plants exposed to fluorine containing acids." Thesis, 2018. https://hdl.handle.net/10539/26652.
Full textAbstract:
A dissertation submitted in fulfilment of the requirement for the degree of Master of Science in Engineering, to the Faculty of Engineering and the Built Environment, School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg, 2018The two hydrofluoric acid (HF) storage tanks used for holding 70% technical grade HF product at the HF plant at Necsa started leaking in March 2012. An evaluation of the failure was conducted in the form of a corrosion failure analysis. It was confirmed that a higher than usual nitric acid (HNO3) content in the technical grade HF stream changed the corrosion mechanisms typically experienced within the HF storage vessels, which then caused the tanks to fail. Immersion type corrosion experiments were done to safely simulate the corrosive environment experienced by the mild steel, stainless steel and nickel alloys used on site, and to predict the change in corrosion rates and characteristics associated with the HNO3 contamination in the HF production plant circuit. Since the corrosion resistance of mild steel in HF is heavily dependent on the thickness of the protective scale on the steel, a series of planned interval corrosion tests (PICTs) was done to reproduce and then examine the oxidefluoride barrier on mild steel coupons in pure 70% HF prior to corrosion tests. These shorter PICTs were also done on the stainless steel and nickel alloys and showed that the prepassivation step had a surface cleaning effect when exposed for only 24 h. Eleven day corrosion tests were conducted to establish the effect of HNO3 concentration and temperature on mild steel corrosion in 70% HF, and to determine the change in corrosion rates and mechanisms associated with HNO3 contamination (0.1-1% HNO3) of the downstream HF products. The corrosion was characterized by analysing the corroded coupons for mass loss, apparent corrosion rates, acid consumptions, visual observations of scale formation and pits, as well as depth profiles from scanning electron microscopy and energy dispersive spectroscopy analyses. Linear relationships were frequently observed when analysing mass losses for the coupons over time, making it possible to define corrosion rates in terms of first order reaction kinetics. The harshest corrosive condition for mild steel in HF was determined to be 1% HNO3 in 70% HF at a constant temperature of 25ºC. The corrosion characteristics of alloys used in the HF plant, as affected by HNO3 impurities (in the range 50–10000 ppm) in the final HF acid product (70% Technical grade) were successfully established. Normalized SA516 Grade 70 mild steel and Monel 400 were found not adequate for use as construction materials in a plant where HNO3 contamination was >100 ppm. However, the corrosion resistance of SS 904 L was suitable under these conditions and was recommended for applications in HF solutions where the presence of an oxygen-containing acid (e.g. HNO3) is consistent. It was recommended that Alloy 31, Alloy 33 or Nirosta 4565S, with higher chromium content (>20 wt% Cr), should be considered for construction material of the HF plant when HNO3 contamination becomes unavoidable. However, if the continued use of mild steel at the plant cannot be avoided, other inhibition strategies tailored to the selective consumption of HNO3 in the HF product stream need to be investigated.
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