<p>Free-flowing water currents such as tides and unregulated water courses could contribute to world electricity production given the emergence of robust technical solutions for extracting the energy. At Uppsala University, a concept for converting water currents to electricity using a vertical axis turbine with fixed blade pitch and a direct drive permanentmagnet generator is studied. A system approach is desired, and in this thesis, a first analysis of two system components, the generator and the turbine, is presented. This thesis also deals with some issues concerning the design and construction of a low speed generator for this application. An experimental generator for verification of simulations has been designed and constructed. For the electromagnetic design, a FEM simulation tool has been used. The construction work has given valuable practical experience concerning for example handling permanent magnets and winding the generator with cable. Simulations and measurements of the experimental generator have been carried out for different speeds and loads. The generator can operate at the speeds and loads corresponding to maximum power capture for different turbines for water current velocities between approximately 0.5 and 2.5 m/s. At higher water current velocities the turbines may need to be run at a tip speed ratio that gives a lower power capture in order to limit the electrical currents in the generator, cavitation of the blades, or mechanical loads. Comparisons of measurements and simulations show an agreement. The FEM simulation tool can be used to simulate and design electrical machines with a low electrical frequency, i.e. 2–16 Hz.</p>

No description available.

<p>Hydrokinetic energy, referring to the energy contained in moving water, is a renewable energy source that has gained much attention the past years. The energy is found in all moving water masses, but is only economical to convert for water masses moving with high velocity, i.e. likely around 1 m/s and above. This energy can for example be found in tidal, ocean and river currents which flow through narrow straits and channels. Along the west coast of Norway, there are many sites where kinetic energy conversion would be possible due to the strong current present. The driving force behind the currents is the tidal wave that progresses northward along the coast and increases in strength. The models that so far have been used for estimating the resource in Norway have been shown to be uncertain since they do not account for the fact that the velocities and the water levels are altered when energy is extracted. These effects can be simulated with numerical models. A channel in the Dal river, the Söderfors channel, is situated downstream a hydropower plant and was simulated with the numerical model MIKE. The water level alteration due to turbines was simulated. It was shown to be a lot less than the water level alteration caused by the level change in the downstream lake. Velocity profiles measured at several different locations were used to estimate how the power coefficient was changed. Four turbine configurations were studied and it was shown that changes in the power coefficient were prominent only for a vertical shear profile with a strong gradient. At the Division of Electricity, studies have been conducted on how to convert hydrokinetic energy to electricity since 2003. The main idea has been to use a system that limits the need for maintenance. The concept studied is a vertical axis turbine directly coupled to a permanent magnet generator. The Söderfors channel has, due to aspects such as the flow properties and velocity, been chosen as a site for an experimental station.</p>

<p>Diamond is a promising material for high-power, high-frequency and hightemperatureelectronics applications, where its outstanding physical propertiescan be fully exploited. It exhibits an extremely high energy gap, veryhigh carrier mobilities, high breakdown field strength, and the highest thermalconductivity of any wide bandgap material. It could therefore producethe fastest switching, the highest power density, and the most efficient electronicdevices obtainable, with applications in the RF power, automotive andaerospace industries. Lightweight diamond devices, capable of high temperatureoperation in harsh environments, could also be used in radiationdetectors and particle physics applications where no other semiconductordevices would survive.The high defect and impurity concentration in natural diamond or polycrystallinehigh-pressure-high-temperature (HPHT) diamond substrates hasmade it difficult to establish reliable results when studying the electronicproperties of diamond. However, recent progress in the growth of high puritySingle-Crystal Chemical Vapor Deposited Diamond (SC-CVD) has openedthe perspective of applications under such extreme conditions based on thistype of artificial diamond.Despite the improvements, there are still many questions which must beanswered. This work will focus on electrical characterization of (SC-CVD)diamond by different measurements techniques such as internal photoemission,I-V, C-V, Hall and in particular, time-of-flight (TOF) carrier driftvelocity measurements. With the mentioned techniques, some importantproperties of diamond such as drift mobilities, lateral carrier transit velocities,compensation ratio and Schottky barrier heights have been investigated.Low compensation ratios (ND/NA) < 10-4 have been achieved in boron-dopeddiamond and a drift mobility of about 860 cm2 / V for the hole transit nearthe surface in a lateral TOF configuration could be measured.</p>

This research explored emergent trends in technical/engineering graphics education as prior research suggested that changes had occurred in the instructional topics and practices of the field. Prior research also showed that instructors wondered if the same topics were taught by graphics professionals as a part of their curriculum at other institutions. The areas researched in this study were: course offerings, student populations, professional development, technical/engineering graphics education, and future research. The study sample of fifty-six (N=56) graphics education instructors was selected from Engineering Design Graphics Division (EDGD) members that were listed in the 2007-2008 membership directory, provided a valid email address to American Society for Engineering Educators (ASEE), had achieved at least a Bachelorâs degree, and taught at least one graphics course a year. The EDGD members were contacted via email and responses were collected by an online survey instrument. Overall, the results were checked for invalid responses, compiled, and then compared to the results of previous research from 1998 and 2004. The results of this study showed a decline in the instruction of: GD&T, manual instruments, 2-D CAD, 3-D modeling, and CAM. The results indicated no change in 3-D constraint-based modeling instruction, but an increase in the instruction of animation. A decline in female students enrolled in technical/engineering graphics courses was also reported; however, an increase was reported in ethic minority students enrolled in the same courses. The results indicated a decline in the number of educational institutions that offered technical/engineering graphics as a major degree, but an increase in institutions that offered a minor in the same field. Furthermore, the results indicated that as time progressed and technology advanced, the topics taught within technical/engineering graphics courses shifted from traditional topics and to new emergent topics. Common concerns of respondents were difficulties remaining up-to-date with changes within the field and the preparedness of incoming students to the field. Possible future trends identified in this study were all software related and included: an increased emphasis on 3-D CAD, the increased instruction of animation, and a migration to online and distance education from traditional classroom instruction. The field of technical/engineering graphics education appeared to be strong and had adapted to industrial advancements and curriculum changes.

This study was conducted in order to discover existing barriers that discourage females from enrolling in technology education (TED) classes in high school and college and to offer suggestions on ways to overcome those barriers. A pilot study was conducted in 2005 at an International Technology Educatorâs Association (ITEA) National Conference to help inform the researcher on the best way to collect data for the study. Participants for the pilot study included female technology education students from several major universities around the country. As a result of the pilot study, qualitative research methods were utilized including a survey for demographics, focus groups, small group interviews, and document analysis. The subjects for the current study were male and female students attending a major university who were enrolled in technology education courses as well as a group of females who were not technology education majors. Three groups were interviewed for the study: one group was comprised of females majoring in technology education, a second group was made up of females enrolled in an introductory graphic communications class who were not technology education majors, and the final group was a group of male technology education majors. Analysis of the data explored possible explanations for and solutions to low female enrollment in technology education and technology-related fields which could influence the way technology education and STEM classes are taught in the future.

The purpose of this study was to identify the quality indicators of visual-based learning material in technology education for grades 7-12. A three-round modified Delphi method was used to answer the following research questions: RQ1: What indicators should quality visual-based learning material in technology education have to be effective and efficient in transmitting information for grades 7-12? RQ2: What are the indicators of the learner?s characteristics that impact the selection of visual-based learning material in technology education for grades 7-12? The quality indicators were determined by consensus reached by a panel of 21 educational experts randomly selected from participants in two NSF funded projects that pilot and field-tested visual learning material in technology education courses. The two funded projects were VisTE and TECH-Know. In the first round, the experts? panel was provided with examples of quality indicators. The example indicators in the first round instrument derived from the literature review. The first round of the modified Delphi method used an open-ended questionnaire format in which the experts were asked to keep, reject, modify or add a new characteristic. The responses generated by the first round contributed to the development of the Round II instrument. In the second round, panelists were asked to value and rank from lowest to highest the items identified on Round I on a 5 point Likert-scale. In Round III the experts? panel was asked to accept or reject the quality indicators derived by the second round. Based on an analysis of data collected on Rounds I, II and III conclusions were drawn.

Thesis (Ph. D.)--Virginia Commonwealth University, 2006. / Prepared for: Dept. of Information Systems. Bibliography: leaves 151-163 .

<p>Min målsättning med denna uppsats har varit att forska kring hur kortvågsradion kan öka rörligheten på svenska förband i utlandsstyrkan. Inledningsvis har jag definerat vad jag menar med manöverkrigsföring, uppdragstaktik, de sex grundläggande förmågorna och radio. Jag har intervjuat individer som varit på enheter som rört sig i terrängen i Afghanistan och Kosovo. Jag har sedan diskuterat kring hur man kan öka rörligeheten genom att använd sig av uppdragstaktik och kortvågsradion. Jag har jämfört ledningsätt och radioanvändande mellan Afghanistan och Kosovo och dragit slutsatser från detta.</p><p>En av slutsatserna som har dragits ur uppsatsen är att det är räckvidden som möjliggör en högre rörlighet genom att enheterna inte blir styrda till att hålla sig inom t.ex. en RAP-täckningskarta utan ger dem större möjlighet att själva välja framryckningsväg och möjliggöra att uppdragstaktik[1] kan utnyttjas på ett effektivare sätt.</p><p>Denna slutsats beskriver hur rörlighet och uppdragstaktik blir effektivare genom att använda sig av kortvågsradion.</p><p>Jag anser att kortvågsradion är ett radiosystem som försvarsmakten böra behålla och utveckla. Det som bör utvecklas är antenner och radio utrustningen som har tagit upp i uppsatsen. Förslag på förbättringar är att antennerna utvecklas så att man kan ha en antenn för alla frekvensområden så man inte behöver stanna fordonet och upprätta en deltaantenn[2] för att kunna sända på den lämpligaste frekvensen vid tillfället. Att det finns en individ vid campen som har som uppgift att uppdaterade frekvenspaketen varje vecka eftersom frekvenserna är väderberoende, för att mögligöra att radioförbindelsen blir så bra som mögligt. Radioapparaterna borde byggas med dagen elektronikkomponenter vilket skulle medföra mindre radioapparater, bättre batteritid och en mer lättmanövrerad radioapparat. </p><p>Jag kommer att avsluta med ett citat ur doktrin för markoperationer som jag anser styrker min uppsats:</p><p><em>”De ledningssystem som försvarsmakten använder ska medge en så stor flexibilitet som mögligt i valet av medel och metoder. Detta innebär att det bör finnas en inbyggd förmåga som möjliggör ledning från såväl en framskjuten plats inom ett operationsområde som från en stabsplats<strong>[3]</strong>”.</em></p><p> </p>

The theme of this dissertation is the design of IT artefactsfor increased well-being in the home. The goal has been toprovide a better understanding of the coupling between designand health, and to give examples of how to design for increasedwell-being. The context for the investigation has been thehome, and various research initiatives in smart homes andIT-supported care. We create our reality in the form of material structuressuch as buildings, products, workplaces and homes. Theseartefacts are a reflection of ourselves, we have created themand we understand ourselves through them. Together withimmaterial artefacts like political systems, educationalsystems and healthcare, they constitute our society. Thetotality of these material and immaterial artefacts forms theconditions of our everyday life. This investigation points at anew way to look at artefacts as social actors in an interactiveworld. In this perspective, use becomes a dialogue andcooperation with the artefact. Design work becomes a carefulcreative practice in which the focus is the interplay betweenthe artefact and its social environment. Stress and ill-healthis an indication that there is an unbalance in the interplay.Well-being on the other hand means that there is a balancebetween the artificial world and the individual. Designpractitioners, and others that create our world, have animportant task in designing new artefacts that do not reproduceobsolete or dysfunctional behaviour. Inspired by coping theories, a salutogenic approach todesign aims at identifying and strengthening the aspects ofartefacts that help us handle adversities. This means to createartefacts that form a world, which is comprehensible,manageable and meaningful. People that live in environmentswhere they cannot influence decisions, with high demands andlow control, are likely to become ill. But people that haveenvironments, in which they receive feedback, support and cancontrol their own situation stay well. With new, complextechnology such as ubiquitous computing, it becomes even moreimportant to support recognition and routines. And it becomesessential in domestic use and in IT-support for the disabledand elderly. The empirical work reported here consists of four casestudies related to IT artefacts for well-being. The casestudies include field studies, critical analysis, designconcepts, prototype building and evaluation. Based on thefindings in these studies, four considerations for design ofinteractive systems for the home are suggested: design forunderstanding, for detecting and managing of errors, fordisabling and for alternative coping. Finally it is suggested that if research is to concernitself not only with evaluations and general laws, but alsowith ideas and practical examples of a better future life–then design knowledge becomes an essential element inresearch. In this endeavour we need more cooperation betweenpractitioners from the social and technical sciences, thehumanities and design. / QC 20100618