This dissertation is directed towards the fundamental understanding of the controlled synthesis of noble-metal (silver, gold, and palladium) and metal oxide (manganese and copper oxide) nanostructures as well as their applications in heterogeneous and plasmonic catalysis. In the first part of this work (Section 1), we provided a general background concerning the science of controlled nanomaterials, their syntheses, properties, and applications in catalysis and plasmonic catalysis. Then, we describe and developed a series of protocols for the synthesis of these nanomaterials with controlled sizes and structures (spheres, cubes, rods, shells, flowers, dendrites, and tadpoles), mainly focusing on the mechanistic understanding of their formation and how physical and chemical parameters (size, shape, composition, surface morphology) may influence/modify their catalytic properties (Sections 2 and 3). In Section 4, we turned our attention for the design of simple protocols for the synthesis of advanced nanomaterials that are interesting for green catalytic transformations applications. In this case, we envisioned the use of MnO2-Au nanomaterials (nanowires and nanoflowers) displaying several properties (unique pore structure, high surface area, ultrasmall Au NPs at the surface, high concentration of oxygen vacancies and Auδ+ species, strong metal-support interactions, and uniform shapes and sizes) that are desirable for catalyzing a series of green oxidation reactions in mild conditions (low temperatures and molecular oxygen or atmospheric air as the oxidants). In Section 5, we have demonstrated that catalysis and optical properties can be merged together to improve catalytic processes, the so called-plasmonic catalysis. This allowed us the use of visible light as the energy input to drive chemical transformations in mild conditions and then provide new insights regarding the various factors that affect SPR-mediated catalytic activities in plasmonic nanostructures. Finally, in Section 6, we focused our attention on how important is to introduce both nanoscience and the synthesis/characterization of nanomaterials having controlled physicochemical features to undergraduate students. Specifically, we have described simple laboratory experiments for the synthesis of nanomaterials (gold nanospheres and Cu(OH)2/CuO nanowires) displaying uniform sizes and shapes in order to investigate and explain their optical properties, catalytic activities and formation mechanisms. / Não consta resumo na publicação.

The goal of this thesis is to demonstrate how user testing can be used to identify and remediate learnability issues of a web application. Experimentation revolved around ASSISTments (www.assistments.org), an intelligent tutoring web application in which teachers create virtual classrooms where they can assign problem sets to their students and gain valuable data which can be used to make informed decisions. Recent log analysis uncovered very low task completion rates for new users on tasks that were intended to be trivial. Suspecting that this could be due to poor user interface design, user tests were conducted to help identify usability problems. Sessions were analyzed, and changes were made between each user test to address issues found. Feedback from user testing led to the implementation of an embedded support system. This support system consisted of a splash page which gave an overview of how the system should be used and a collection of context-sensitive tooltips which tried to give the user instructions on what to do as well as explain various parts of the interface. A randomized control trial was performed to measure the effectiveness of the embedded support. 69 participants were shown one of two interfaces: one with embedded support and one without. Task completion rates were analyzed for each of the groups. We found that the support system was able to influence which links a user clicked. However, although the support system was intended to address poor task completion rates, users in the conditions had similar task completion rates regardless of whether the support system was enabled.

Because of its high specific strength, durability, and biocompatibility, titanium is a widely used material for orthopedic implants. However, its insufficient binding with the surrounding bone tissue regularly leads to stress shielding, bone resorption and implant loosening. A promising solution to improve adhesion is to modify the implant surface chemistry and topography by coating it with a protein-eluting polyelectrolyte complex. Bone morphogenetic protein 2 (BMP-2), a potent osteoconductive growth factor, was adsorbed onto the surface of anodized titanium, and polyelectrolyte multilayer (PEM) coatings prepared from solutions of poly-L-histidine (PLH) and poly(methacrylic acid) (PMAA) were built on top of the BMP-2. The effect of solution pH during the deposition process was investigated. High levels of BMP-2 released over several months were achieved. Approximately 2 μg/cm² of BMP-2 were initially adsorbed on the anodized titanium and a pH-dependent release behavior was observed, with more stable coatings assembled at pH = 6-7. Three different diffusion regimes could be determined from the release profiles: an initial burst release, a sustained release regime and a depletion regime. Mass adsorption monitoring using quartz crystal microbalance with dissipation monitoring (QCM-D) showed that PLH was adsorbed in greater quantities than PMAA, and that more mass was adsorbed per bilayer as the number of bilayers grew. Moreover, the pH of the water used during the rinsing step significantly impacted the composition of the multilayer. Atomic force microscopy (AFM) and contact angle analysis (CAA) were used to determine the topography and surface energy of the PEMs. No visible change was observed in surface morphology as the assembly pH was varied, whereas the surface energy decreased for samples prepared at more basic pH. These variations indicate that the influence of the initial BMP-2 layer can be felt throughout the PEM and impact its surface structure.

With the wide usage of online tutoring systems, researchers become interested in mining data from logged files of these systems, so as to get better understanding of students. Varieties of aspects of students’ learning have become focus of studies, such as modeling students’ mastery status and affects. On the other hand, Randomized Controlled Trial (RCT), which is an unbiased method for getting insights of education, finds its way in Intelligent Tutoring System. Firstly, people are curious about what kind of settings would work better. Secondly, such a tutoring system, with lots of students and teachers using it, provides an opportunity for building a RCT infrastructure underlying the system. With the increasing interest in Data mining and RCTs, the thesis focuses on these two aspects. In the first part, we focus on analyzing and mining data from ASSISTments, an online tutoring system run by a team in Worcester Polytechnic Institute. Through the data, we try to answer several questions from different aspects of students learning. The first question we try to answer is what matters more to student modeling, skill information or student information. The second question is whether it is necessary to model students’ learning at different opportunity count. The third question is about the benefits of using partial credit, rather than binary credit as measurement of students’ learning in RCTs. The fourth question focuses on the amount that students spent Wheel Spinning in the tutoring system. The fifth questions studies the tradeoff between the mastery threshold and the time spent in the tutoring system. By answering the five questions, we both propose machine learning methodology that can be applied in educational data mining, and present findings from analyzing and mining the data. In the second part, we focused on RCTs within ASSISTments. Firstly, we looked at a pilot study of reassessment and relearning, which suggested a better system setting to improve students’ robust learning. Secondly, we proposed the idea to build an infrastructure of learning within ASSISTments, which provides the opportunities to improve the whole educational environment.

Catalisadores Ziegler-Natta (Z-N) de 4ª geração são preparados com suporte de dicloreto de magnésio com morfologia controlada, obtidos a partir de adutos etanólicos de dicloreto de magnésio (MgCl2.nEtOH). O objetivo deste trabalho foi otimizar o balanço entre as variáveis independentes concentração de reagentes, velocidade de agitação da emulsão e pressão de transferência, na preparação do aduto com controle morfológico. Os adutos etanólicos com controle da morfologia esférica foram preparados pela transferência controlada do aduto fundido a 125 ºC e precipitação por resfriamento brusco (quenching) em não-solvente a – 50 ºC, utilizando o método Controlled Turbulence Emulsion Method (CTEM). A ativação do MgCl2.nEtOH foi feita pela rota química para remoção do etanol e consequente aumento da área superficial do suporte. Os adutos foram preparados com razão molar EtOH/MgCl2 de 3,5 ou 63% (p/p) de etanol. Os experimentos foram realizados segundo planejamento fatorial 23 a dois níveis e ponto central replicado. As variáveis dependentes foram o diâmetro médio e distribuição de tamanho das partículas do suporte, densidade aparente compactada, morfologia e teor de álcool incorporado no aduto. Os catalisadores Z-N’s foram obtidos a partir dos suportes tratados com TiCl4 e um doador de elétrons interno, e testados em polimerização padrão de propileno. Foi observado que o controle do tamanho (diâmetro médio) da partícula do suporte é altamente dependente da velocidade de transferência, controlada pela pressão no reator de fusão. A concentração do reagente ([MgCl2]) teve efeito significativo nas quatro variáveis dependentes. A velocidade de agitação no reator de fusão ou da emulsão do aduto fundido teve efeito significativo somente na morfologia do suporte, sendo este efeito menor que o observado para a pressão de transferência. A velocidade de agitação não teve significância no processo de transferência CTEM, sendo este mais suscetível a variação da pressão no reator. / 4th Generation Ziegler-Natta catalysts (Z-N catalysts) are prepared with magnesium dichloride support with controlled morphology, obtained from ethanolic adducts of magnesium dichloride (MgCl2.nEtOH). The objective of this work was to optimize the balance between the independent variables reagent concentration, emulsion agitation speed and transfer pressure, in the preparation of the adduct with morphological control. The ethanolic adducts with spherical morphology control were prepared by controlled transfer of the molten adduct at 125 °C and quenching in nonsolvent at - 50 °C using the Controlled Turbulence Emulsion Method (CTEM). The activation of MgCl2.nEtOH was done by chemical route to remove the ethanol and consequently increase the surface area of the support. The adducts were prepared with EtOH/MgCl2 molar ratio of 3.5 or 63% (w/w) ethanol. The experiments were performed according to factorial design 23 at two levels and replicated central point. The dependent variables were the mean diameter and particle size distribution of the carrier, compacted bulk density, morphology and alcohol content incorporated in the adduct. The Z-N’s catalysts were obtained from TiCl4-treated media and an internal electron donor, and tested in standard polypropylene polymerization. It has been observed that size control (median diameter) of the carrier particle is highly dependent on the transfer rate, controlled by the pressure in the fusion reactor. The concentration of the reagent ( [MgCl2] ) had a significant effect on the four dependent variables. The stirring rate in the melt reactor or the cast adduct emulsion had significant effect only on the morphology of the support, this effect being smaller than that observed for the transfer pressure. The stirring speed was not significant in the CTEM transfer process, which is more susceptible to pressure variation in the reactor.

<p>Controlled drainage is a management strategy designed to mitigate water quality issues caused by subsurface drainage. To improve controlled drainage system management and better understand its hydrological and environmental effects, this study analyzed water table recession rate, as well as drain flow, nitrate and phosphorus loads of both free and controlled drainage systems, and simulated the hydrology of a free drainage system to evaluate surface runoff and ponding at the Davis Purdue Agricultural Center located in Eastern Indiana. </p> <p>Statistical analyses, including paired watershed approach and paired t-test, indicated that controlled drainage had a statistically significant effect (<i>p</i>-value <0.01) on the rate of water table fall and reduced the water table recession rate by 29% to 62%. The slower recession rate caused by controlled drainage can have negative impacts on crop growth and trafficability by causing the water table to remain at a detrimental level for longer. This finding can be used by farmers and other decision-makers to improve the management of controlled drainage systems by actively managing the system during storm events. </p> <p>A method was developed to estimate drain flow during missing periods using the Hooghoudt equation and continuous water table observations. Estimated drain flow was combined with nutrient concentrations to show that controlled drainage decreased annual nitrate loads significantly (p<0.05) by 25% and 39% in two paired plots, while annual soluble reactive phosphorus (SRP) and total phosphorus (TP) loads were not significantly different. These results underscore the potential of controlled drainage to reduce nitrate losses from drained landscapes with the higher level of outlet control during the non-growing season (winter) providing about 70% of annual water quality benefits and the lower level used during the growing season (summer) providing about 30%. </p> <p>Three different methods including monitored water table depth, a digital photo time series and the DRAINMOD model simulations were used to determine the generation process of surface ponding and runoff and the frequency of incidence. The estimated annual water balance indicated that only 7% of annual precipitation contributed to surface runoff. Results from both simulations and observations indicated that all of the ponding events were generated as a result of saturation excess process rather than infiltration excess.</p> <p>Overall, nitrate transport through controlled drainage was lower than free drainage, indicating the drainage water quality benefits of controlled drainage, but water table remained at a higher level for longer when drainage was controlled. This can have negative impacts on crop yields, when water table is above a detrimental level, and can also increase the potential of nutrient transport through surface runoff since the saturation excess was the main reason for generating runoff at this field.</p>

<p>Daily nitrate-N, soluble reactive phosphorus and total phosphorus loads in subsurface drainage were quantified in an agricultural farm field in eastern Indiana (Davis Purdue Agricultural Center).</p> <p><b>Site description:</b> The data was collected from the field W at Davis Purdue Agricultural Center (DPAC) located in eastern Indiana. Field W is relatively flat (slope < 1%), with 0.16 km2 total area, divided into four plots, northwest (NW), southwest (SW), northeast (NE), and southeast (SE) with areas ranging from 3.5 ha to 3.7 ha. The four soil series at the site range from very poorly to somewhat poorly drained, with a small portion of moderately well drained series. The subsurface drainage system was installed in 2004, with 10-cm laterals having an approximate depth of 1 m and spacing of 14 m, resulting in a drainage intensity of 1.1 cm day-1 and drainage coefficient of 1 cm day-1. Drainage in the SE and NW plots was controlled at two different levels during some periods depending on the season, while the SW and NE were allowed to drain freely. This field has been in a corn-soybean rotation since 2011 and in continuous corn before that, and was managed using chisel-plow tillage in the fall and field cultivator tillage in the spring during the study period. Nitrogen (N) and phosphorus (P) fertilizers were applied at different rates prior to and after planting corn. Phosphorus was also applied prior to soybean planting in two of the three soybean years. The rate and timing of fertilizer applications were uniform for all plots and were based on Purdue Extension recommendations. Further details of the site management and data are available in Abendroth et al. (2017). More information about this site and fertilizer application can be found in Saadat et al., 2018.</p> <p><b>Sampling strategy and load calculation:</b> Automated water samplers (ISCO) were used to draw samples from the drainage outlet flow of each plot. Samples were collected every hour when flow was present except during winter, and combined into weekly composite samples varying in length from twice a week to biweekly. During the winter, water samples were collected manually to avoid freezing problems, approximately every week whenever flow was present. Samples were kept frozen until analysis and then analyzed on a SEAL Analytical AQ2 auto-analyzer to be tested for nitrate+nitrite-N (referred to nitrate-N), soluble reactive phosphorus (SRP) and total phosphorus (TP) according to US EPA methods.</p> <p>Daily nitrate-N, SRP and TP concentration values needed for the load calculations were estimated using linear interpolation. After estimating daily concentrations, daily loads were calculated by multiplying the daily drain flow by estimated daily concentrations.</p> <p><b>References: </b>Saadat, S., Bowling, L., Frankenberger, J. and Kladivko, E., 2018. Nitrate and phosphorus transport through subsurface drains under free and controlled drainage. <i>Water research, 142: </i>196-207.</p><br>

As redes de sensores sem fio (RSSF) ganham maior visibilidade a cada ano, e a sua utilização é cada vez mais imprescindível no sensoriamento dos mais diversos ambientes. Estas redes podem ser instaladas em praticamente todos os tipos de ambientes, graças ao seu tamanho reduzido, sua facilidade de comunicação e seu baixo custo. Esta tecnologia permite transportar os dados através de nós que utilizam algoritmos de roteamento oferecendo resistência a falhas. O conhecimento das principais arquiteturas e dos protocolos envolvidos na comunicação, bem como do comportamento destas redes em ambientes reais, é de extrema importância para a compreensão do funcionamento da rede e dos fenômenos que afetam o seu desempenho. Este trabalho apresenta a utilização de uma RSSF baseada no dispositivo Mica2dot, desenvolvido pela Universidade de Berkeley, no monitoramento de parâmetros ambientais de uma sala limpa utilizada na construção de dispositivos semicondutores. Apresentamos a caracterização dos dispositivos e do ambiente em questão; também avaliamos dois protocolos de roteamento neste ambiente e fatores que afetam o funcionamento do sistema de rádio, como a variação do RSSI (Receive Signal Strength Indicator). Os protocolos de roteamento escolhidos para esta avaliação foram o TOSB (TinyOs Beaconing), que é o protocolo padrão do sistema operacional TinyOS, e o PROC (Proactive ROuting with Coordination), que apresenta características de pró-atividade. Os protocolos foram avaliados segundo as métricas de consumo de energia e taxa média de entrega de pacotes. / Wireless sensor networks (WSNs) are growing year after year, and its use is being more and more indispensable in sensing the most varied environments. These networks can be installed in almost all kinds of environments, thanks to its reduced size, its easiness of communication and its low cost. One of the main characteristics of this technology is the capacity of transporting data through the nodes that use router algorithms, offering a good resistance to failures. The knowledge of the main architectures and of the protocols involved in communication, as well the behavior of these networks in real environments, is of extreme importance to the understanding of the working conditions of the network and of the phenomena that affect its performance. This piece of work aims to present a study related to the use of a WSN based on the Mica2dot device developed by the University of Berkeley, in the monitoring of the environmental parameters of a clean room used to the construction of semiconductor devices. This work presents the characterization of the devices and of the environment in question, as well evaluates some factors that affect the working of the radio system and evaluates two router protocols in this environment. The chosen router protocols for this evaluation were TOSB (TinyOs Beaconing) that is the standard protocol of the operational system TinyOS, and PROC (Proactive Routing with Coordination), that presents some pro-active characteristics. The protocols were evaluated according to the measurement of the energy consumption and average rate of deliver of packages.

Clinical decision-making about psychological interventions is best supported by robust evidence and informed patient choice. Randomised controlled trials (RCTs) are the current gold standard in evaluating intervention effectiveness and identifying harm. At present, RCTs of psychological intervention are unlikely to include measurement of adverse effects and this is in part due to lack of consensus about this topic. A Delphi study was conducted with a panel of both professionals and people with personal experience of face-to-face psychotherapy across the spectrum of mental health difficulties to seek consensus on what to include on a measure of adverse effects. Fifty-four items derived from an initial list of 147 items generated by the panel, are included on the APTMOS outcome measure, which now in it's preliminary form now requires validation before use in RCTs. To date, the evidence for psychological interventions for psychosis and schizophrenia has not been synthesised, which is important to inform patient choice and decision-making. Network meta-analysis compares multiple interventions using direct evidence from randomised controlled trials (RCTs) and indirect evidence from the network. A systematic review of the literature identified 91 RCTs across 23 different intervention/control group categories. Psychological interventions were more effective at reducing total symptoms of psychosis than control groups. One intervention with a low risk of bias, mindfulness-based psychoeducation, was consistently identified as most effective, with large effect sizes. Subgroup analyses identified differential effectiveness in different settings and for different subgroups. Further high quality RCT evidence of the highest ranked interventions is required to inform updates to clinical guidelines of psychological interventions for psychosis.

<p>Potassium is an essential nutrient, that has been labeled a shortfall nutrient by recent Dietary Guidelines for Americans Advisory Committees. Increases in potassium intake have been linked to improvements in cardiovascular and other metabolic health outcomes. Blood pressure (BP) has often been cited as the primary criterion for determining potassium requirements. Hypertension (HTN), or high BP, is a primary risk factor for cardiovascular disease and other circulatory diseases. Cardiovascular disease (CVD) is responsible for the 31% of deaths worldwide. Findings from the Agency for Healthcare Research and Quality report (which informed the recently released Dietary Reference Intakes for sodium (Na) and potassium) on potassium intake and chronic disease concluded, with a moderate strength of evidence, that increasing potassium intake decreases BP, particularly among those with HTN. Although, of the 18 randomized controlled trials assessed by the AHRQ, only 4 were dietary interventions, the rest involved potassium supplementation. Observational studies also show a consistent bone benefit with increased potassium rich fruit and vegetable intakes in cohorts spanning adolescents to the elderly. In clinical trials, higher potassium intakes through supplementation have been associated with reduced urinary calcium (Ca) excretion and improvement in Ca balance. Although, similar to BP, intervention trials assessing the impact of dietary potassium on bone are lacking. Controlled feeding studies looking specifically at increases in potassium from food are sparse, leaving a large knowledge gap in the field for a nutrient with an important potential health impact. In general, little is known about whole-body potassium retention, with the few studies conducted lacking consistency and rigor in methods and design. What potassium retention means in terms of adequacy, or how higher or lower retention may influence specific health outcomes is understudied and not well understood. </p> <p>Utilizing a randomized, cross-over, controlled feeding clinical study with complete metabolic balance measures, our research aims to begin filling these gaps, looking specifically at the effects of potassium intake via potato sources and a potassium supplement on BP and vascular outcomes, as well as how the source of potassium may influence potassium, Na and Ca whole-body balance. </p> <p>This dissertation will discuss the physiology of potassium intake, how this may affect potassium, Na, and Ca retention, and in turn what influence this has on vascular and bone related health outcomes. Overall the goal of this research is to address the question: What is the importance of dietary potassium, and how can it benefit cardiovascular and skeletal health?</p>