No description available.

Arsenic contamination in groundwater is a worldwide problem. The existing portable field test kits can not provide accurate results when the arsenic concentration is around 10 μg L-1 or lower. This research first was focused on the development and validation of methods in which portable instrumentation, such as electrochemistry instruments or quartz crystal microbalances, could be used to accurately determine arsenic concentrations in water even when the concentration is below 10 μg L-1. A modified anodic stripping voltammetry (ASV) and cathodic stripping voltammetry (CSV) method with measurement at a microarray electrode manufactured by TraceDetect Inc. was developed. When the ASV method with a gold electrode was applied for real water analysis, the detection limit of arsenite was 2.2 μg L-1, and for arsenate was 0.13 μg L-1. In the CSV method the more commonly used hanging mercury drop electrode was replaced with a mercury film array electrode. Under the optimum condition, this method had a detection limit for arsenite of 0.58 μg L-1 and for arsenate of 2.7 μg L-1. A method for the determination of arsenic using a quartz crystal microbalance was developed in which the crystal surface was modified in situ by dithiolthreitol, an arsenite-selective ingand. The method was applied to real water sample analysis with a limit of 0.6 μg L-1. The second was concerned with an investigation of the kinetics of the reactions that are the basis of several currently available field test kits (as exemplified by the Hach Kit) using inductively coupled plasma mass spectrometry (ICP-MS) with the goal of improving the performance of the test kit. The time for arsine gas reaches to the maximum concentration in the headspace of the vessel was about 60 min without continuous stirring and only 20% of arsenic was absorbed on the test strip. To speed up the arsine generation, continuous stirring condition can be applied. It also made more arsine absorbed on the test strip. The SEM study proves the structure of the darker colored compound. For the lighter colored compounds, the information is not enough to make a conclusion.

No description available.

The work presented in this thesis involves the development of a new analytical method for predicting the transient behaviour of squirrel cage induction motors subjected to pulsating mechanical loads such as a reciprocating compressor. The objective of this project is to develop analysis that will better inform the subsequent design method for determining the rating of industrial induction motors driving an oscillatory load. The analytical approach used to determine the transient response of the motor is based upon the harmonic coupling inductance method which is capable of accommodating any stator winding arrangement used in industrial motor designs. The analytical work described in this thesis includes the response of an induction motor subjected to a general oscillating load in terms of the damping and synchronous torque components. These torque components can be used to determine the additional system inertia required to limit the motor speed and current oscillations to predetermined levels. The work further identifies the motor-load natural resonant frequency and demonstrates the potential issues when driving a general oscillatory load at or close to this frequency. The analytical model was cross-checked using software modelling in Matlab for an industrial squirrel cage induction motor driving a selection of compressor loads. The simulation results were finally correlated with a detailed experimental validation in the laboratory using a squirrel cage induction motor connected to a permanent magnet synchronous motor controlled electronically to simulate general oscillatory load.

abstract: This dissertation studies the scheduling in two stochastic networks, a co-located wireless network and an outpatient healthcare network, both of which have a cyclic planning horizon and a deadline-related performance metric. For the co-located wireless network, a time-slotted system is considered. A cycle of planning horizon is called a frame, which consists of a fixed number of time slots. The size of the frame is determined by the upper-layer applications. Packets with deadlines arrive at the beginning of each frame and will be discarded if missing their deadlines, which are in the same frame. Each link of the network is associated with a quality of service constraint and an average transmit power constraint. For this system, a MaxWeight-type problem for which the solutions achieve the throughput optimality is formulated. Since the computational complexity of solving the MaxWeight-type problem with exhaustive search is exponential even for a single-link system, a greedy algorithm with complexity O(nlog(n)) is proposed, which is also throughput optimal. The outpatient healthcare network is modeled as a discrete-time queueing network, in which patients receive diagnosis and treatment planning that involves collaboration between multiple service stations. For each patient, only the root (first) appointment can be scheduled as the following appointments evolve stochastically. The cyclic planing horizon is a week. The root appointment is optimized to maximize the proportion of patients that can complete their care by a class-dependent deadline. In the optimization algorithm, the sojourn time of patients in the healthcare network is approximated with a doubly-stochastic phase-type distribution. To address the computational intractability, a mean-field model with convergence guarantees is proposed. A linear programming-based policy improvement framework is developed, which can approximately solve the original large-scale stochastic optimization in queueing networks of realistic sizes. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2020

Thesis advisor: Juliet B. Schor / This dissertation examines the climate movement as a social field where actors vie for position and capital. This competition strongly influences framing, tactics, and strategy, while it ultimately bears on the effectiveness of mobilization. I analyzed the climate activist field (CAF) through a case study of resistance against a gas pipeline project. In the first phase of resistance, I found there to be a divergence between local activists with little to no experience in the CAF and climate activists operating within it. In the second phase, after climate activists had taken over, there was a division among climate activists themselves. Here, climate activists carried themselves and made decisions based on what they thought was objectively the correct thing to do. However, activists’ practices (encompassing decisions around tactics and strategy but also their judgments and disposition) were structured through the competition for the rewards of the CAF—Climate Activist Capital (CAC), especially Symbolic CAC—and the associated increased status for activists. I used a mixed method approach involving a survey (N=146), participant observation (200 hours), and interviews (N=51). The survey collected data on activist background and preferences, as well as subjective assessments of their own participation and indicators of economic and cultural capital. Participant observation in a range of groups and social spaces allowed for analysis of activist practices in real, observable ways. Both the survey and participant observation informed a purposive interviewing strategy that collected data from the most heavily involved to more peripheral activists. The analysis sought to locate patterns in activist background, quantity and composition of capital, and practices. Differences in activist practices were hypothesized to be the outcome of the interrelation among: an actor’s background embedded in the habitus; an actor’s volume and composition of capital, as well as their social trajectory; and the competition for capital and position within the CAF (itself structured by actors, their backgrounds and practices, and influence from other fields). The hypothesis received mixed support in the data. Participants in the resistance were not conscious of how their preferences for tactics and strategy were guided by the competition to valorize Symbolic CAC inflected by activist orientation, relatively internal or external. Structured by the field that they help construct, climate activists’ practices and the overall effort to stop the pipeline project became increasingly internally oriented, situated antagonistically with the field of power. This resulted in an increased distance between climate activists and non-climate activists as well as a focus on civil disobedience to the exclusion of other tactics. The dissertation represents a novel approach to understanding dynamics within the climate movement and contributes to three areas of research. First, my research on resistance against fossil fuel infrastructure addresses a deficit of empirical scholarship on climate activism, especially at the local level. Second, I contribute to the social movement scholarship on strategic choices by locating them between individual rational calculation and predetermined agency-less decisions by focusing on the effects of activist field position. Third, the research extends Bourdieusian scholarship by testing his theoretical schema built around social reproduction in a field that is organized around social change. In bringing a Bourdieusian approach to movement scholarship and the climate movement in particular, the research delivers an analysis that weaves together micro-level social processes—activists and their practices objectively positioned in the CAF—with an historically developed CAF at the macro-level. The analysis is pertinent not just to scholars but to climate activists and activists more broadly. Ultimately, I argue that the climate movement will be served best by drawing on the distinct advantages of both internal and external spaces in the CAF. This requires more reflexivity and introspection among climate activists so they may understand how their position informs their practices and how they can more consciously mediate the position-to-practices process and bend them in contextually appropriate ways, which will lead to more effective climate activists and enhanced climate movement efficacy. / Thesis (PhD) — Boston College, 2019. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Sociology.

An integrated field and structural analysis of the Mitten Park fault-fold structure, northwestern Colorado and northeastern Utah, examines its structural origin. The Mitten Park structure is a modified fault-propagation-fold. This new model incorporates faulting, folding, and fracturing in one deformational event to produce the Mitten Park fault and associated monocline. The largest structure in the study area is the Mitten Park fault and associated monocline. The Mitten Park fault has approximately 127 meters (415 feet) of net slip, strikes S28°W and dips 55°WNW. In the footwall, net shortening was accommodated by reverse and normal faulting. Faulting was the result of northwest-southeast directed shortening. Reverse faulting accommodated the majority of the fault-related strain along the fault's trace and resulted in net shortening. However, normal faults in the overturned limb of the footwall of the Mitten Park fault also accommodated northwest-southeast directed shortening. Folds in the study area are asymmetrical and statistically cylindrical in both the footwall and the hanging wall. Folding facilitates northwest-southeast directed shortening. There is a direct correlation between changes in the strike and dip of the fault plane and changes in the trend and plunge of fold axis in the footwall. Fracture orientations show no significant variation in geometry from hanging wall to footwall. Fracture intensity increases with proximity to the Mitten Park fault. Balanced cross sections of the Mitten Park area use a modified fault-propagation- fold model and are also constrained by field observations and interlimb angles of folds. Total shortening in the study area is 13.5% and was accommodated by the hanging wall, the footwall, and the Mitten Park fault. The hanging wall accommodated 70.8% of total shortening, the footwall accommodated 14.9% of total shortening, and the Mitten Park fault accommodated 14.3% of total shortening. The significant amount of strain in the footwall of the fault is different from classical models of fault-propagation-folds, which depict a rigid undeformed footwall.

By developing strong, self-sustaining individuals in organisations, employees will need to withstand the forces of stressors and be able to cope with continuous changes within their working environment. To move the equilibrium level from the current to the desired condition, the field of forces must be altered - by adding driving forces and by removing restraining forces. An individual's sense of coherence may either alleviate or aggravate reactions to a stressor and moderate the impact of occupational stressors on the individual's affective outcomes. The objectives of this study were to validate the 13-item version of the Orientation to Life Questionnaire (OLQ) (Antonovsky, 1987) and to determine the experience of employees with high levels of sense of coherence regarding helping and restraining factors within the workplace (compared to that of those with a low sense of coherence). A cross-sectional s w e y design was used. The total population (N = 2 678) of employees in a financial institution in Gauteng was used in this study. Random samples of groups with a strong (n = 300) and low (n = 300) sense of coherence were taken for purposes of the qualitative study. The OLQ (Antonovsky, 1987) and a biographical questionnaire were administered. The scale showed acceptable reliability and construct validity. The study set out to determine the applicability of the theoretical model of sense of coherence to employees in a financial institution. Reliability analysis revealed that the three subscales of sense of coherence were sufficiently internally consistent. The reliability of the measuring instrument were assessed with the use of Cronbach alpha coefficients. Descriptive statistics (e.g. mean and standard deviations) were used to analyse the data. By using the structural equation modelling approach, a one-dimensional factor structure for sense of coherence amongst employees in a financial institution emerged. The reliability analysis revealed that the alpha scores were acceptable. It can therefore be concluded that the 13-item version of the OLQ is a reliable and valid measuring instrument. The results showed that although employee groups with high and low levels of sense of coherence are experiencing similar helping and restraining factors within their working environment, helping factors are being experienced with a higher frequency by groups with high levels of sense of coherence and restraining factors with a higher frequency by groups with low levels of sense of coherence. Recommendations were made for future research. / Thesis (M.A. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2007

A hipertensão é uma doença crônica não transmissível e mais freqüente na população sendo o principal fator de risco para complicações cardiovasculares, tais como acidente vascular cerebral e infarto agudo do miocárdio. Na presente pesquisa estão sendo estudados os fármacos utilizados no tratamento da hipertensão mais especificamente, os bloqueadores do canal de cálcio do grupo diidropiridínicos: besilato de anlodipino, nifedipino e nimodipino. O objetivo desse trabalho foi verificar a estabilidade intrínseca dos fármacos besilato de anlodipino, nifedipino e nimodipino, para isto foram utilizadas as seguintes técnicas: testes indicativos de estabilidade utilizando as técnicas de espectrofotometria na região do Ultravioleta/Visível (UV/VIS) e Cromatografia em fase Líquida de Alta Eficiência (CLAE). Termogravimetria/ Termogravimetria Derivada (TG/DTG), Calorimetria Exploratória Diferencial (DSC), Difração de Raios X (DRX), Espectroscopia de absorção na região do Infravermelho com Transformada de Fourier (FTIR) e Microscopia Eletrônica de Varredura (MEV). Para o fármaco besilato de anlodipino (AB) pelo método de degradação forçada, analisado por espectrofotometria no UV/VIS, as condições para a análise espectrofotométrica foram metanol e água a uma proporção de (5:45 v/v) e a segunda diluição com água. A leitura foi efetuada a 364,4nm. A linearidade foi estabelecida na faixa de 40,0-65,0 µg/mL e o coeficiente de correlação foi (r) 0,9992. O método cromatográfico, mostrou o diferente comportamento das substâncias nifedipino e nimodipino diante dos meios básicos, ácido, neutro e oxidativo. As condições para a substância nifedipino foram coluna LiChrospher®100 RP-18 (5µm) Merck® fase móvel constituída por metanol e água (45:55v/v), fluxo 1.0 mL/min, tempo de retenção 5,1min, detecção UV a 234nm e vazão de 1.0 mL/min. Foi obtida uma linearidade no intervalo de 5.0-55.0 µg/mL coeficiente de correlação (r) =0,9964. E para a substância nimodipino foram coluna LiChrospher®100 RP-18 (5µm) Merck® fase móvel constituída por acetonitrila e água (55:45v/v), fluxo 1.0mL/min, tempo de retenção 5,8 min, detecção UV a 235 nm e vazão de 1.0mL/min. Foi obtida uma linearidade no intervalo de 5.0-55.0 µg/mL coeficiente de correlação (r) =0,9964. Os resultados obtidos das curvas TG/DTG e DSC mostraram o perfil da decomposição térmica das substâncias estudadas pela Calorimetria Exploratória Diferencial. A análise dos resultados de DRX e DSC mostraram que não há evidências de polimorfismo nessas substâncias. No entanto nas análises de Espectroscopia de absorção na região do infravermelho com Transformada de Fourier (FTIR) não foram encontradas diferenças significativas na matéria-prima e no padrão de referência. As análises de MEV permitiram observar a cristalinidade das substâncias estudadas. / Hypertension is the most frequent non-communicable chronic disease in the population being the main factor of risk for cardiovascular complications, such as stroke and acute myocardial infarction. In this work, active pharmaceutical ingredients used to treat hypertension were studied, more specifically the blockers calcium channel dihydropyridine group: amlodipine besylate, nifedipine and nimodipine. The aim of this study was to determine the intrinsic stability of amlodipine besylate, nifedipine and nimodipine. For this purpose the following stability test techniques were used: UV/VIS spectrophotometry and chromatography Net phase High Performance. Thermogravimetry/Derivative Thermogravimetry (TG/ DTG), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), Fourier Transformed Infrared absorption (FTIR) and Scanning Electron Microscopy (MEV). For drug amlodipine besylate (AB) by forced degradation method analyzed by spectrophotometry UV/VIS spectrophotometric conditions for the analysis were methanol and water at a ratio (5:45v/v) and the second dilution with water. The reading was made at 364,4nm. The linearity was established in the range of 40.0 to 65.0 mg/mL and the correlation coefficient was (r) 0.9992. The chromatographic method showed different behavior of nifedipine and nimodipine substances on the basic means, acid, neutral and oxidative. The conditions for nifedipine were LiChrospher®100 RP-18 column (5µm) Merck® mobile phase consisting of methanol and water (45:55v/v), flow 1.0 mL/min, retention time 5,1min, UV detection at 234 nm and flow of 1.0 mL/min. Linearity was obtained within the range of 5.0-55.0 mg/mL correlation coefficient (r) = 0.9964. And for nimodipine the parameters were: LiChrospher®100 RP-18 column (5µm) Merck® mobile phase consisted of acetonitrile: water (55:45v/v), flow 1.0 mL/min, retention time 5,8min, UV detection at 235nm and flow of 1.0 mL/min. The linearity was obtained within the range of 5.0- 55.0 mg/mL correlation coefficient (r) = 0.9964. The results of TG/DTG and DSC curves presented the profile of the thermal decomposition of the substances studied by DSC. The results of XRD and DSC presented no evidence of polymorphism in these analyzes, however, according to analyzes of absorption spectroscopy in the infrared (FTIR) there were no significant differences in the raw materials and standard reference. SEM analyzes allowed to observe the crystallinity of the studied substances.

A hipertensão é uma doença crônica não transmissível e mais freqüente na população sendo o principal fator de risco para complicações cardiovasculares, tais como acidente vascular cerebral e infarto agudo do miocárdio. Na presente pesquisa estão sendo estudados os fármacos utilizados no tratamento da hipertensão mais especificamente, os bloqueadores do canal de cálcio do grupo diidropiridínicos: besilato de anlodipino, nifedipino e nimodipino. O objetivo desse trabalho foi verificar a estabilidade intrínseca dos fármacos besilato de anlodipino, nifedipino e nimodipino, para isto foram utilizadas as seguintes técnicas: testes indicativos de estabilidade utilizando as técnicas de espectrofotometria na região do Ultravioleta/Visível (UV/VIS) e Cromatografia em fase Líquida de Alta Eficiência (CLAE). Termogravimetria/ Termogravimetria Derivada (TG/DTG), Calorimetria Exploratória Diferencial (DSC), Difração de Raios X (DRX), Espectroscopia de absorção na região do Infravermelho com Transformada de Fourier (FTIR) e Microscopia Eletrônica de Varredura (MEV). Para o fármaco besilato de anlodipino (AB) pelo método de degradação forçada, analisado por espectrofotometria no UV/VIS, as condições para a análise espectrofotométrica foram metanol e água a uma proporção de (5:45 v/v) e a segunda diluição com água. A leitura foi efetuada a 364,4nm. A linearidade foi estabelecida na faixa de 40,0-65,0 µg/mL e o coeficiente de correlação foi (r) 0,9992. O método cromatográfico, mostrou o diferente comportamento das substâncias nifedipino e nimodipino diante dos meios básicos, ácido, neutro e oxidativo. As condições para a substância nifedipino foram coluna LiChrospher®100 RP-18 (5µm) Merck® fase móvel constituída por metanol e água (45:55v/v), fluxo 1.0 mL/min, tempo de retenção 5,1min, detecção UV a 234nm e vazão de 1.0 mL/min. Foi obtida uma linearidade no intervalo de 5.0-55.0 µg/mL coeficiente de correlação (r) =0,9964. E para a substância nimodipino foram coluna LiChrospher®100 RP-18 (5µm) Merck® fase móvel constituída por acetonitrila e água (55:45v/v), fluxo 1.0mL/min, tempo de retenção 5,8 min, detecção UV a 235 nm e vazão de 1.0mL/min. Foi obtida uma linearidade no intervalo de 5.0-55.0 µg/mL coeficiente de correlação (r) =0,9964. Os resultados obtidos das curvas TG/DTG e DSC mostraram o perfil da decomposição térmica das substâncias estudadas pela Calorimetria Exploratória Diferencial. A análise dos resultados de DRX e DSC mostraram que não há evidências de polimorfismo nessas substâncias. No entanto nas análises de Espectroscopia de absorção na região do infravermelho com Transformada de Fourier (FTIR) não foram encontradas diferenças significativas na matéria-prima e no padrão de referência. As análises de MEV permitiram observar a cristalinidade das substâncias estudadas. / Hypertension is the most frequent non-communicable chronic disease in the population being the main factor of risk for cardiovascular complications, such as stroke and acute myocardial infarction. In this work, active pharmaceutical ingredients used to treat hypertension were studied, more specifically the blockers calcium channel dihydropyridine group: amlodipine besylate, nifedipine and nimodipine. The aim of this study was to determine the intrinsic stability of amlodipine besylate, nifedipine and nimodipine. For this purpose the following stability test techniques were used: UV/VIS spectrophotometry and chromatography Net phase High Performance. Thermogravimetry/Derivative Thermogravimetry (TG/ DTG), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), Fourier Transformed Infrared absorption (FTIR) and Scanning Electron Microscopy (MEV). For drug amlodipine besylate (AB) by forced degradation method analyzed by spectrophotometry UV/VIS spectrophotometric conditions for the analysis were methanol and water at a ratio (5:45v/v) and the second dilution with water. The reading was made at 364,4nm. The linearity was established in the range of 40.0 to 65.0 mg/mL and the correlation coefficient was (r) 0.9992. The chromatographic method showed different behavior of nifedipine and nimodipine substances on the basic means, acid, neutral and oxidative. The conditions for nifedipine were LiChrospher®100 RP-18 column (5µm) Merck® mobile phase consisting of methanol and water (45:55v/v), flow 1.0 mL/min, retention time 5,1min, UV detection at 234 nm and flow of 1.0 mL/min. Linearity was obtained within the range of 5.0-55.0 mg/mL correlation coefficient (r) = 0.9964. And for nimodipine the parameters were: LiChrospher®100 RP-18 column (5µm) Merck® mobile phase consisted of acetonitrile: water (55:45v/v), flow 1.0 mL/min, retention time 5,8min, UV detection at 235nm and flow of 1.0 mL/min. The linearity was obtained within the range of 5.0- 55.0 mg/mL correlation coefficient (r) = 0.9964. The results of TG/DTG and DSC curves presented the profile of the thermal decomposition of the substances studied by DSC. The results of XRD and DSC presented no evidence of polymorphism in these analyzes, however, according to analyzes of absorption spectroscopy in the infrared (FTIR) there were no significant differences in the raw materials and standard reference. SEM analyzes allowed to observe the crystallinity of the studied substances.