The imperfections in the semiconductor fabrication process and uncertainty in operating environment of VLSI circuits have emerged as critical challenges for the semiconductor industry. These are generally termed as process and environment variations, which lead to uncertainty in performance and unreliable operation of the circuits. These problems have been further aggravated in scaled nanometer technologies due to increased process variations and reduced operating voltage. Several techniques have been proposed recently for designing digital VLSI circuits under variability. However, most of them have targeted ASICs and custom designs. The flexibility of reconfiguration and unknown end application in FPGAs make design under variability different for FPGAs compared to ASICs and custom designs, and the techniques proposed for ASICs and custom designs cannot be directly applied to FPGAs. An important design consideration is to minimize the modifications in architecture and circuit to reduce the cost of changing the existing FPGA architecture and circuit. The focus of this work can be divided into three principal categories, which are, improving timing yield under process variations, improving power yield under process variations and improving the voltage profile in the FPGA power grid. The work on timing yield improvement proposes routing architecture enhancements along with CAD techniques to improve the timing yield of FPGA designs. The work on power yield improvement for FPGAs selects a low power dual-Vdd FPGA design as the baseline FPGA architecture for developing power yield enhancement techniques. It proposes CAD techniques to improve the power yield of FPGAs. A mathematical programming technique is proposed to determine the parameters of the buffers in the interconnect such as the sizes of the transistors and threshold voltage of the transistors, all within constraints, such that the leakage variability is minimized under delay constraints. Two CAD techniques are investigated and proposed to improve the supply voltage profile of the power grids in FPGAs. The first technique is a place and route technique and the second technique is a logic clustering technique to reduce IR-drops and spatial variation of supply voltage in the power grid.

The permanent and intensive changes taking place nowadays in societal, social, economical, organizational and even private lives shift a great responsibility on a comprehensive school that has to create equal opportunities for every learner to acquire education and abilities to adapt in a constantly changing environment. The implemented educational reforms constituted a significant progress of the educational system of the Republic of Lithuania, however, the increasing number of learners that do not acquire qualitative comprehensive education are not able to compete in society and face social exclusion. The following are thought to be the most urgent educational problems in European Union and Lithuania: qualitative education, education for all, as drop-out of every child from a formal education system is a great loss for a state in terms of demography, morality, economy, culture and etc. With consideration to all the mentioned above, the following research problem has been formulated – what are the possibilities of a basic school in decreasing the drop-out of the school children. The object of the research - the possibilities of a basic school in decreasing the drop-out of the school children. The aim of the research is to analyse the possibilities of a basic school in decreasing the drop-out of the school children. The following objectives assist in revealing the aim of the research: 1) Carry out the theoretical analysis of school children drop-out from school by... [to full text]

The objective of the present work was systematic investigation of water-based headspace single-drop microextraction (SDME) technique, its conjunction with capillary electrophoresis, and application for the analysis of volatile inorganic compounds (cyanide and ammonium) in biomedical and environmental samples. Theoretically evaluated and experimentally confirmed that the manipulation in the volatility of the analyte by its chemical modification in the sample and/or in the acceptor phase is the most effective way to enhance the extraction performance in headspace SDME. Maximum extraction efficiency for cyanide was observed in the pH range 4.5–7.5, where cyanide anion is completely transferred into volatile HCN. Complete cyanide recoveries (≥96%) from metal-cyanide complexes were obtained by using two ligand-exchange reagents (ethylenediamine and dithizone). Maximum extraction efficiency was observed by the extraction of ammonia from alkaline samples (pH≥11) with neutral or slightly acidic acceptor phase (pH 3-7). Compared to existing methods water-based headspace SDME is significantly faster and simpler. In addition, proposed technique does not require any sample pre-treatment (deproteinization, acidic/alkaline distillation, etc.) and thus is much less susceptible to interferences. Finally, it offers possibility to choice of a wider variety of solvents and, consequently, enhances the range of extractable analytes as well as the range of analytical methods that can be coupled... [to full text] / Daktaro disertacijoje nuodugniai ištirtas mikroekstrakcijos iš viršerdvės vandens lašu metodas, apjungtas su kapiliarine elektroforeze bei pritaikytas lakių neorganinių junginių (cianido ir amonio) koncentravimui ir nustatymui biomedicininiuose ir aplinkos objektuose. Teoriniais skaičiavimais parodyta ir eksperimentiškai patvirtinta, kad efektyviausias būdas mikroekstrakcijos iš viršerdvės efektyvumui pagerinti – analitės lakumo didinimas chemiškai modifikuojant ją prieš ekstrakciją ir/arba jos lakumo mažinimas modifikuojant ją akceptorinėje fazėje. Maksimalus cianido mikroekstrakcijos efektyvumas pasiekiamas pH srityje 4,5- 7,5, kur cianidas kiekybiškai pervedamas į lakų HCN. Ištyrus cianido mikroekstrakciją tirpiklio lašu iš metalų cianidinių kompleksų tirpalų nustatyta, kad kiekybiškas silpnai surišto cianido suardymas (cianido išgavos siekia ≥96%) pasiekiamas panaudojus ligandų mainus etilendiamino ir ditizono mišiniu. Maksimalus amonio mikroekstrakcijos efektyvumas pasiekiamas ekstrahuojant jį iš pašarmintų mėginių (pH≥11) akceptorine faze, kurios pH 3-7. Lyginant su standartiniais metodais, siūlomas metodas yra greitesnis ir paprastesnis, visiškai eliminuojama mėginio matricos įtaka, nereikalingos jokios drastiškos (deproteinizacija, veikimas rūgštimis/šarmais, distiliacija ir pan.) manipuliacijos su mėginiu, todėl išvengiama mėginio matricos įtakos. Mikroekstrakcija iš viršerdvės vandens lašu praplečia mikroekstrakcijos metodų taikymo sritis: atveriama galimybė labai... [toliau žr. visą tekstą]

This study sought to understand the lived experience of disengagement from formal schooling of five young Aboriginal women in a mid-Northern community. Using the qualitative methodology of narrative inquiry, and through a series of guided open-ended interviews, this research explored each participant’s experiences as a learner; informally and in school. Analysis of the personal histories of learning shared by the participants enabled the identification of attributes of best-remembered learning experiences and also elements that contributed to marginalization and dis-continuing of school. Key elements for each learner clustered around relationship and connectedness. Contexts of optimal learning as revealed in the narratives can be characterized as authentic, situated, experiential, guided, and often culturally-relevant. Marginalization and dis-continuing of school were related to: a sense of emotional insecurity in the school, the need for community and a sense of belonging, disrespectful treatment and relational bullying by teachers and/or peers, administrative policy related to placement and psycho-social needs, and restrictive curricular decisions. The participants’ desire to learn and continuing pursuit of learning goals, although out of school, is expressed in the title of this thesis by Participant A as she speaks for all in saying, “I’m still learning” (PA#1, p. 3). Recommendations for formal schooling are made based on the needs and preferences expressed by the participants and by the institutional circumstances revealed in the narratives that affected engagement and dis-engagement. / Thesis (Master, Education) -- Queen's University, 2007-08-09 15:48:56.987

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An experimental study was conducted in order to investigate the two-phase-flow phenomena in a mini-size, horizontal impacting tee junction. The test section was machined in an acrylic block with a rectangular cross-section of 1.87-mm height × 20-mm width on the inlet and outlet sides. Air-water mixtures at 200 kPa (abs) and room temperature were used as the test fluids. Four flow regimes were identified visually: bubbly, plug, churn, and annular over the ranges of gas and liquid superficial velocities of 0.04 ≤ JG ≤ 10 m/s and 0.02 ≤ JL ≤ 0.7 m/s, respectively, and a flow regime map was developed. The present flow-regime map was compared with several experimental maps. It is thought from those comparisons that the channel height has a more significant role in determining the flow-regime boundaries than the hydraulic diameter. The two-phase fully-developed pressure gradient was measured in the inlet and the outlet sides of the junction for six different inlet conditions and various mass splits at the junction. Comparisons were conducted between the present data and former correlations. The correlations that agreed best with the present data were identified. Five single-phase test sets were performed. In each set of experiments, the pressure distribution was measured for the whole range of the mass split ratio, Wi/W1. The pressure drop at the junction at each value of Wi/W1 was calculated. Values of the pressure-loss coefficient, , were calculated at various Wi/W1 and inlet Reynolds number. The pressure-loss coefficient was strongly dependent on the inlet Reynolds number in the laminar region, while the results for the turbulent region were almost coincident. Numerical simulations of single-phase flow in an impacting tee junction of identical dimensions to that of the present test-section were performed to confirm the results of the experiments. Phase-redistribution experiments were conducted covering all four inlet flow regimes and models were proposed for predicting the experimental data. Good agreement in terms of magnitude and trend was obtained between the present experimental data and the proposed model. New correlations were developed for the single- and two-phase pressure drop in the junction.

An experimental apparatus was designed and built to study the thermal autoxidative carbon deposition, or coking, in the fuel injection nozzles of small gas turbine engines. The apparatus is a simplified representation of an aircraft fuel system, consisting of a preheating section and a test section, which is a passage that simulates the geometry, temperatures, pressures and flow rates seen by the fuel injection nozzles. Preliminary experiments were performed to verify the functionality of the apparatus. Pressure drop across the test section was measured throughout the experiments to monitor deposit buildup, and an effective reduction in test section diameter due to deposit blockage was calculated. The preliminary experiments showed that the pressure drop increased more significantly for higher test section temperatures, and that pressure drop measurement is an effective method of monitoring and quantifying deposit buildup.

An experimental apparatus was designed and built to study the thermal autoxidative carbon deposition, or coking, in the fuel injection nozzles of small gas turbine engines. The apparatus is a simplified representation of an aircraft fuel system, consisting of a preheating section and a test section, which is a passage that simulates the geometry, temperatures, pressures and flow rates seen by the fuel injection nozzles. Preliminary experiments were performed to verify the functionality of the apparatus. Pressure drop across the test section was measured throughout the experiments to monitor deposit buildup, and an effective reduction in test section diameter due to deposit blockage was calculated. The preliminary experiments showed that the pressure drop increased more significantly for higher test section temperatures, and that pressure drop measurement is an effective method of monitoring and quantifying deposit buildup.