<p>Disturbances in power systems are common and they result in electromechanical oscillations called power swing. The power swings could be severe and it may lead to loss of synchronism among the interconnected generators. This is referred to as out-of-step condition. The voltage and current swings during an out-of-step condition damage power system equipments and also cause unwanted operations of various protective devices. The protection systems require an effective algorithm for fast and accurate detection of out-of-step condition. </p> <p>This research is focused on the development of a simple and effective out-of-step relay capable of detecting out-of-step condition in a complex power system. To achieve this, the research has gone through four distinct stages: development of an algorithm, simulation, hardware implementation and its testing. </p> <p>An out-of-step algorithm is proposed based on equal area criterion in time domain. The equal area criterion in time domain is obtained by modifying the traditional equal area criterion in power angle domain. A single machine infinite bus system, a two machine infinite bus system and a three machine infinite bus system and a 17-bus multiple machines system are used as case studies and are modeled using simulation tool(PSCAD). </p> <p>To test the effectiveness of the proposed algorithm, various out-of-step conditions are simulated by applying disturbances at various locations in the above chosen power system configurations. For hardware implementation and testing of the algorithm, a digital signal processing board (ADSP-BF533 from Analog Devices ) is used. To test the performance of the developed digital relay in a closed loop, real time power system signals are necessary and therefore for this purpose, a Real Time Digital Simulator (RTDS) available in the power research laboratory is used. The RTDS simulator mimics the actual power systems in real time. The signals required by the relays can be tapped from the RTDS and the signals coming from relay can be fed back into the RTDS, which makes the closed loop testing of the digital relay possible. This research has yielded a simple out-of-step algorithm and unlike the other out-of-step detection techniques proposed in the literature does not need offline system studies to arrive at a solution.The developed digital out-of-step relay is capable of making decisions based only on the information available from its point of installation, thus it avoids the communication devices which is advantageous for the out-of-step protection of a complex power system. Finally, the simulation results show that the proposed algorithm can be applied to any power configurations and is faster compared to the conventional concentric rectangle schemes used in the literature.</p>

A child’s level of physical activity is an important component of that child’s health. Our understanding of physical activity patterns in children is limited in rural settings, and virtually absent for climates with snow cover. Opportunities for physical activity intervention need to be identified. PURPOSE: Investigation of the relationships between pedometer-measured physical activity, body composition and aerobic performance in rural children in the winter and examination of within-day variation in stepping behavior using interval pedometry. METHODS: Aerobic performance (20 m shuttle run) with “talk test” validation and body composition (BMI, BF) were measured during mid-winter during the school year in 8 to 10 year old children. Pedometer step counts were recorded at 6 intervals throughout the day for 7 days. RESULTS: Fifty-six subjects (22 males and 34 females, mean age 9.09 (0.49), had the following measurements; BMI 17.9 (3.3), BF% 24.3 (9.5) (tricep/calf), 10,465 (±2506) steps/day, VO2 45.12 ml/kg/min (±2.87), shuttle run stage 3.0 (±1.34). Weekday steps/day (11,422 ±2573) were greater than weekend (8,112, ±3499) steps/day for both boys and girls (p<0.01). Town children recorded 1800 more steps/day than out of town children (p<0.01). All measures of body composition were found to be significantly related to aerobic power (p<0.01). Weekday steps were related to aerobic performance. The fittest (upper 1/3) children were leaner and had more afternoon school steps, and higher afternoon school step rates. CONCLUSION: Daily step counts were 2000-4000 steps lower than other studies and may be an impact of winter in Manitoba or the rural setting. This was consistent with overall low aerobic performance and higher adiposity of the children. Interval pedometry was capable of identifying differences in activity patterns between most and least fit children in rural Manitoba providing for targeted intervention strategies. / October 2006

A request of material change when performing repairs on composite parts of SAABs JAS 39 Gripen has lead to the initiation of this project. The aim is to create a quicker and more robust repair method. The requested method of repair is to use a direct-cured repair patch made of CFRP fabric instead of CFRP tape and to mount the patch with a scarf joint, see Figure 1.1. The fabric patch should then provide a robust quasi-isotropic repair, where the operator not is dependent of complete design data such as ply-directions etc. Today tape repairs are made on tape laminate and fabric repairs made on fabric laminate. The new method is to repair tape laminate with a fabric patch. This project will evaluate the possibility of implementing this method. The work started with a literature study to find out how repairs in composite parts of the airframe are being performed today. SAABs in-house analytical tools were then used to try to predict the results and examine some of the details in the questions at issue. Finite element models were then constructed to simulate a previous physical test program conducted to validate a repair method using a step joint and a direct-cured repair patch. If the FE models could show similar results as the physical tests the results from the FE models then can be assumed to be credible. The results of this project indicate that the change from fabric to tape in the repair patch can be done without disturbing the load path of a quasi isotropic composite laminate. Fabric repairs in orthotropic composite plates results in a knock-down of about 40%. The use of a scarf joint instead of a step joint should also work well as the repair patches show similar strains in the centre of the patches. The difference between step joint and scarf joint is the strain near the edge of the patch. It increases with scarf joint and it may lead to an earlier fibre failure in the repair patch. Results from the analysis of the bonded joint indicate that a scarf joint yields in a lower and more evenly distributed shear stress than the step joint. This indicates that the bonded joint in the step joint will reach failure earlier then the scarf joint.

For over a century, physicians have prescribed x-ray radiation to destroy or impede the growth of cancerous tumours. Modern radiation therapy machines shape the radiation beam to balance the competing goals of maximizing irradiation of cancerous tissue and minimizing irradiation of healthy tissue, an objective complicated by tumour motion during the treatment and errors positioning the patient to align the tumour with the radiation beam. Recent medical imaging advances have motivated interest in using feedback during radiation therapy to track the tumour in real time and mitigate these complications. This thesis investigates how real-time feedback control can be used to track the tumour and focus the radiation beam tightly around the tumour. Improving on these results, a feedback control system is proposed for intensity modulated radiation therapy which allows a non-uniform radiation dose to be applied to the tumour. Motivated by the results of the proposed control systems, this thesis also examines two theoretical control problems: estimating the output of an unknown system when a sensor delay prevents its direct measurement, and designing a controller to provide an arbitrarily fast nonovershooting step response.

<p>Disturbances in power systems are common and they result in electromechanical oscillations called power swing. The power swings could be severe and it may lead to loss of synchronism among the interconnected generators. This is referred to as out-of-step condition. The voltage and current swings during an out-of-step condition damage power system equipments and also cause unwanted operations of various protective devices. The protection systems require an effective algorithm for fast and accurate detection of out-of-step condition. </p> <p>This research is focused on the development of a simple and effective out-of-step relay capable of detecting out-of-step condition in a complex power system. To achieve this, the research has gone through four distinct stages: development of an algorithm, simulation, hardware implementation and its testing. </p> <p>An out-of-step algorithm is proposed based on equal area criterion in time domain. The equal area criterion in time domain is obtained by modifying the traditional equal area criterion in power angle domain. A single machine infinite bus system, a two machine infinite bus system and a three machine infinite bus system and a 17-bus multiple machines system are used as case studies and are modeled using simulation tool(PSCAD). </p> <p>To test the effectiveness of the proposed algorithm, various out-of-step conditions are simulated by applying disturbances at various locations in the above chosen power system configurations. For hardware implementation and testing of the algorithm, a digital signal processing board (ADSP-BF533 from Analog Devices ) is used. To test the performance of the developed digital relay in a closed loop, real time power system signals are necessary and therefore for this purpose, a Real Time Digital Simulator (RTDS) available in the power research laboratory is used. The RTDS simulator mimics the actual power systems in real time. The signals required by the relays can be tapped from the RTDS and the signals coming from relay can be fed back into the RTDS, which makes the closed loop testing of the digital relay possible. This research has yielded a simple out-of-step algorithm and unlike the other out-of-step detection techniques proposed in the literature does not need offline system studies to arrive at a solution.The developed digital out-of-step relay is capable of making decisions based only on the information available from its point of installation, thus it avoids the communication devices which is advantageous for the out-of-step protection of a complex power system. Finally, the simulation results show that the proposed algorithm can be applied to any power configurations and is faster compared to the conventional concentric rectangle schemes used in the literature.</p>

Both developing and developed countries have witnessed the very heart position of small business in the contribution of economic growth and job creation. Nevertheless, the appetite for funds of new enterprises is still not satisfied nowadays, which limits the further blossom of entrepreneurship. Concerning about this problem, our research tries to investigate and describe financing sources of companies in seed/early stage and understand the implications of entrepreneurial leadership in the process of fundraising. Besides, this study involves three business ecosystems: America, France and China in the international context.Following the grounded theory as the researching path, this thesis is considered as a combination of realistic research about financing sources and interpretative research about entrepreneurial leadership. The study is based upon secondary data, which are widely gathered from USA, France and China. In order to achieve in-depth perspectives, empirical explorations are conducted mainly through example studies and face-to-face dialogues with experts including an entrepreneur, a consultant in relation with investors, a bank manager and a project manager.A comprehensive understanding is realized as a result of this research:• American business ecosystem proves its leading position in fundraising support for bootstrap-step companies. As to French ecosystem, it is evolving and represents various particularities regarding regulations, structural mentalities and policies. The Chinese one is fairly different due to the affection of the Communism regime but also the particularly important role of network in doing business.• Entrepreneurial leadership is helpful in fundraising process. And enactment of leadership is quite different due to diverse culture and financing sources. Through the thesis, we interpret how entrepreneurial leadership could be helpful for fundraising in each business ecosystem.• Beyond academic sphere, this research reveals significant benefits and potentials for bridging fund flow among three business ecosystems. It shows a big entrepreneurial opportunity for people who have knowledge and network to break cultural boundaries and construct this “bridge”.In no wise this study aims at explaining or prescribing. By studying each ecosystem for entrepreneurial leaders, we hope to establish an understanding of this topic that could be further examined.

The main purpose of this study was to compare how the Step-by-Step™ (S-b-S) and the newly developed How Was School Today (HWST) prototype can support participation in narrative activities for a 10-year-old boy with complex communication needs (CCN) when he interacts with two typically developed peers. The researchers wanted to find out how the use of the different communication aids affected interaction. The S-b-S is a low technology communication device with a voice recording function. The HWST prototype is a simulation of the HWST system, which is a high technology system that automatically collects information and creates stories about what the user has done in school. The researchers focused on different aspects of gaze and questions as vital communicative practices for the boy‟s involvement in the interaction, and hence, thestory telling activity. The data was analysed mainly qualitatively with conversation analysis (CA). A descriptive quantitative analysis was also developed. The results indicate that the HWST prototype provides a framework for establishment of joint orientation towards the prototype and questions about it. The S-b-S on the other hand creates a context in which it is easier to establish eye contact. There is an uneven distribution of questions with a much higher frequency in the session where the HWST prototype was used. There are not many studies on narrative ability in children with CCN together with peers. Future research on shared stories in natural environments is suggested. / Denna studies huvudsyfte var att jämföra hur kommunikationshjälpmedlen Step-by-Step™ (S-b-S) och den nyligen utvecklade How Was School Today-prototypen (HWST) kan stödja deltagandet i berättandeaktiviteter för en 10-årig pojke med komplexa kommunikativa behov när han interagerar med två typiskt utvecklade kamrater. Forskarna ville ta reda på hur användandet av de olika kommunikationshjälpmedlen påverkade interaktionen. S-b-S är ett lågteknologiskt kommunikationshjälpmedel med röstinspelningsfunktion. HWST-prototypen är en simulering av HWST-systemet, som är ett högteknologiskt system som automatisk samlar in information och skapar berättelser om vad användaren har gjort i skolan. Forskarnas fokuserade på olika aspekter av blickriktning och frågor, som centrala kommunikativa praktiker för pojkens involvering i interaktionen, och därmed i berättandet. Data analyserades främst kvalitativt med metoden samtalsanalys. Det utvecklades även en deskriptiv kvantitativ analys. Resultaten visar att HWSTprototypen förser samtalet med ett ramverk som underlättar etablerandet av gemensam orientering till prototypen och frågor som rör den. S-b-S skapar å andra sidan en kontext i vilken det är lättare att utveckla ögonkontakt. Det är en ojämn fördelning av frågor, med en mycket högre frekvens i sessionen där HWST-prototypen användes. Det finns inte många studier om narrativ förmåga hos barn med CCN i samtal med kamrater. Framtida studier av berättande i naturliga miljöer föreslås. / "How was School today…?" in the Wild

The Georgia Institute of Technology (Georgia Tech), one of the nations leading engineering schools, has limited institutional history of collaboration with surrounding K-12 schools. K-12 outreach is not a part of Georgia Techs mission, though recent years have seen greater outreach activities. Campus organizations have sponsored tutoring, academic schools have sponsored recruitment fairs and the College of Engineering has established a partnership with a high school. Two offices within Georgia Tech, the Center for the Enhancement of Teaching and Learning (CETL) and the Center for Education Integrating Science, Math and Computers (CEISMC), have been working to expand and deepen Georgia Techs K-12 outreach through a National Science Foundation grant program combining graduate student development and K-12 outreach. Through this program, the Student and Teacher Enhancement Partnership (STEP), CETL and CEISMC seek to build meaningful and lasting relationships between Georgia Tech and local high schools. Given the novelty of mutually rewarding relationships between Georgia Tech and local high schools, this study attempts to account for differences in outcomes of the (STEP) program over its first three years. STEPs Project Officers at Georgia Tech developed dyadic relationships with high school personnel with the same programmatic goals in mind. However, at the end of three years, some of these pairings were more mutually rewarding. A narrative analysis of these relationships is presented through case studies and tested against a literature-based logic model depicting factors likely to lead to successful, inter-organizational partnerships.

The aims of this thesis to investigate the two step loading of Ti/APC-2 hybrid nanocomposite laminates and their notched effect. Ti/APC-2 laminates were composed of three layers of titanium sheets and two layers of APC-2. Nanoparticles SiO2 were dispersed uniformly on the interfaces of APC-2 with the optimal amount of 1 wt %. Then, APC-2 was stacked according to cross-ply [0/90]s and quasi-isotropic [0/45/90/-45] sequences. The modified diaphragm curing process was adopted to fabricate the hybrid panels for minimal impact of production. The panels were cur into samples and drilled an diameter hole in the center with diameters of 4 or 6 mm. Both tension and fatigue tests were carried out with MTS 810 universal testing machine at room temperature. Also, two-step loading tests include high¡÷low and low¡÷high tests, were conducted. 0.9£mnom is denoted as high load and 0.7£mnom low load for two-step loading spectrum. In both high¡÷low and low¡÷high step loadings the first step is to do cyclic tests at a half life of the corresponding load, and then finish it due to last step load. From the received results, some conclusions were made. First, the ultimate load of notched cross-ply samples was reduced about 50% and the notched quasi-isotropic samples reduced about 30% compared to their unnotched counterparts. Second, the S-N curves are very close for both centrally notched samples of diameters 4 mm and 6 mm in cross-ply and quasi-isotropic samples. Third, quasi-isotropic samples had higher average values of cumulative damage than cross-ply samples. Because of notched effect centrally notched samples of diameters 4 mm had higher average values of cumulative damage than centrally notched samples of diameters 6 mm.

This dissertation presents a numerical simulation of three-dimensional flow and heat transfer in a channel with a backward-facing step. Flow was considered to be steady, incompressible, and laminar. The flow medium was treated to be radiatively participating. Governing momentum equations, energy equation, and the radiative equation were solved by a finite volume method. Extensive validation studies were carried out. As part of the validation study, three-dimensional combined convection and radiation in a rectangular channel without a backward-facing step was studied. The SIMPLE algorithm was used to link pressure and velocity fields. The combined convective-radiative heat transfer were studied by varying three parameters, i.e. optical thickness ( H τ =0.1, 0.2, and 0.4) and scattering albedo ( ω=0, 0.25, 0.5, 0.75 and 1). Variation of thermophysical properties with temperature was considered in this study. In this work consideration was given only to cooling. Effects of those radiative parameters on velocity, bulk temperature, and Nusselt number are presented in detail. The fluid with a hot inlet compared to a cold wall was cooled in a relatively short distance from the channel inlet because of the radiation effect. The thermal penetration decreased with a decrease in optical thickness and an increase in scattering albedo. Thermal penetration increased with increasing optical thickness and decreasing scattering albedo. The reattachment length varied with temperature due to variation of thermophysical properties with temperature.