Hollow fibre and spiral wound membrane (SWM) modules are the most common commercially available membrane modules. The latter dominate especially for RO, NF and UF and are the focus of this study. The main difficulty these types of modules face is concentration polarisation. In SWM modules, the spacer meshes that keep the membrane leaves apart also help reduce the effects of concentration polarisation. The spacer filaments act as flow obstructions, and thus encourage flow destabilisation and increase mass transfer enhancement. One of the detrimental aspects of the use of spacers is an increase of pressure losses in SWM modules. This study analyses the mechanisms that give rise to mass transfer enhancement in narrow spacer-filled channels, and investigates the relationship between flow destabilisation, energy losses and mass transfer. It shows that the regions of high mass transfer on the membrane surface correlate mainly with those regions where the fluid flow is towards the membrane. Based on the insights gained from this analysis, a series of multi-layer spacer designs are proposed and evaluated. In this thesis, a Computational Fluid Dynamics (CFD) model was used to simulate steady and unsteady flows with mass transfer in two- and three-dimensional narrow channels containing spacers. A solute with a Schmidt number of 600 dissolving from the wall and channel Reynolds numbers up to 1683 were considered. A fully-developed concentration profile boundary condition was utilised in order to reduce the computational costs of the simulations. Time averaging and Fourier analysis were performed to gain insight into the dynamics of the different flow regimes encountered, ranging from steady flow to vortex shedding behind the spacer filaments. The relationships between 3D flow effects, vortical flow, pressure drop and mass transfer enhancement were explored. Greater mass transfer enhancement was found for the 3D geometries modelled, when compared with 2D geometries, due to wall shear perpendicular to the bulk flow and streamwise vortices. Form drag was identified as the main component of energy loss for the flow conditions analysed. Implications for the design of improved spacer meshes, such as extra layers of spacer filaments to direct the bulk flow towards the membrane walls, and filament profiles to reduce form drag are discussed.

The ubiquity of Internet connectivity means there is a greater need for computer network safety and security. Cost-effective secure computing networks and broadband applications not only need a sophisticated cryptosystem to accelerate data encryption, but also need substantial computational power to handle large data streams. Reconfigurable System-on-Chip (rSoC) technology is well suited to accelerate network cryptographic applications by implementing the entire computing application on a single reconfigurable chip. Hardware-software co-design and hardware-software communication are some key questions involved in using this rSoC technology. This thesis investigates how best to accelerate a cryptographic application using rSoC technology. Some background on FPGAs, reconfigurable computing, inter-process communication methods, hardware/software co-design, cryptography in general, and 3DES in particular are firstly introduced. Some existing reconfigurable computing systems and 3DES implementations on FPGA are then reviewed and analyzed. A new general hardware-software architecture, which consists of a CPU, memories, customized peripherals and buses on a single FPGA chip, is designed to accelerate the security application. The 3DES application is divided into four functional modules: input, subkey generation, data processing, and output modules. Shared memory with semaphores is chosen for the inter-module communication. A complete inter-module communication solution is presented for hardware and software module communications. A generic component, HWCOM, is designed for those communications which involve hardware modules. Experimental results show that using two buffers as shared memories between communication modules and increasing shared memory size are good methods for transferring data between hardware/software modules more efficiently. When investigating the best hardware/software partition scheme, all 3DES modules are first executed in software on the FPGA. The experimental results of 83Kbps encryption throughput indicate that the software-only solution is not satisfactory. Through profiling, the bottleneck is shown to be the data processing module and the subkey generation module, which are then implemented in hardware. Experimental results show an improved 179Mbps throughput. This presents over 2000 times acceleration compared to software and shows that the hardware-software co-implementation can efficiently accelerate the 3DES application with good performance and flexibility.

The current energy situation is taking a turn towards renewable energies, due to the new pacts to curb global warming. These agreements, together with governmental aid, are facilitating an escalation in the production and improvement of new energy systems and the price decrease due to a larger-scale production. Within these energy alternatives, solar energy is found, specifically the subject to be treated in this project is photovoltaic energy, due to its exponential growth in the last 10 years, new tools are being developed for its monitoring and modelling. Therefore, the main objective of this thesis is to develop a method  for installation testing of a PV-system. The method should give the installed nominal power of the system and show if the maximum power point trackers work as expected. A large PV-system was installed on the roof of Gävle Arenaby during 2017. A measurement system for monitoring of the power of the system and of the solar irradiance was installed. Different parameters have been taken into account for the adjustment of the model that vary the performance of the system. These factors are: the irradiance received, the module temperature and the angle of incidence. It has been concluded that the results obtained indicate a correct adjustment of the theoretical power against the real power, which means, a correct operation of the generated model. Besides, the expected power follows a linear trend, reaching the power set by the manufacturer for Standard Test Conditions. The results show that the monitored modules-strings fulffill the promised performance and the method for installation testing work as expected. The linear correlation between corrected power and irradiance means that the maximum power point tracker in the inverter works independent of the power.

INTRODUCTION: Medical school curricula are shifting away from passive traditional lecture styles to a more engaging active learning style. This includes flipped-classroom and problem-based learning. While there is evidence that active learning promotes memory retention, critical thinking and self-directed learning, it is also met with resistance from both educators who lack the time or pedagogical training and students who have grown comfortable with passive lecture-based learning. In 2015, Boston University School of Medicine implemented an active learning online learning module, Softchalk, utilized by first year students in an integrated course, Principles Integrating Science and Medicine. Based on survey analysis, Softchalk was a successful learning tool and was once again used in 2016. Improvements were made to Softchalk for the upcoming 2016 class. These consisted of making the learning modules more condensed, consistent and Softchalk was no longer requiring them to be completed for a grade. OBJECTIVE: Assess and compare 2015 vs. 2016 survey results to gauge the student’s perceived effectiveness of Softchalk. METHODS: A mixed-methods survey analysis study was administered to first year medical students enrolled in the biochemistry course at Boston University School of Medicine (total of 180 matriculates). The survey was a voluntary and anonymous. It consisted of two open-ended free response questions and six Likert Scale questions. RESULTS: Softchalk has been incorporated into the curriculum for two years, 2015 and 2016 and thus student responses were compared. There was a significant difference in both student perception of Softchalk providing a foundation for the course (p= 0.001) and helping the students stay on track (p=0.024). However, there was no significant difference between the 2015 and 2016 cohorts in regards to Softchalk providing more effective questions (p= 0.08) or the use of Softchalk as a teaching tool (p=0.051). In the free-response questions, student responses were compared and showed that Softchalk was much more favorable in 2016 than 2015. CONCLUSION: Perceptions of Softchalk were much more favorable in 2016 in comparison to 2015. This thesis is arguing that the main factor in the increased perception of Softchalk was based on the fact that it was no longer required to complete. In 2015, Softchalk was presented as an optional tool for learning instead of another requirement to complete. Students who utilized Softchalk were more likely to have a favorable outlook because it conducive to their learning style. In addition, Softchalk allows students to develop self-directed learning skills by allowing them to be in control of their learning experience, which becomes increasingly important for the clinical clerkship learning and beyond.

This thesis explores the relatively under-researched experiences of module design of academics employed within one UK university. In all, 96 people responded to an initial e-questionnaire survey, and 23 of these participated in follow-up semi-structured interviews. The qualitative data collected from both sources is the main focus of discussion. The thesis contextualises the research by presenting a brief description of the university of study and a sense of the social and political context of higher education in the few years preceding the onset of the project. Following this, there is a review of the existing literature around module and curriculum design. A separate chapter outlines the mixed methods employed to collect the data and the form of Interpretative Phenomenological Analysis (IPA) used to theme the qualitative data provided by the survey and interviews. The findings supported previous studies, but there was some contradictory data concerning assessment design, the value of the institutional approval procedures, and the usefulness of involving students in the design process. This study found that, as a result of the effect of institutional processes and documents on design, the consequence of changing student profiles (particularly around assessment), and the obligation staff feel to their students (despite their expressed lack of available time and resources), module design (and redesign) is more situation-informed than evidence-informed. It concludes that module designers employ a realistic and pragmatic approach to the process, even when their views, attitudes, and consciences around the rights and wrongs of the design process are sometimes questioned.

Measurement uncertainty is an indication of the quality of a given measurement and ultimately translates into the confidence with which a decision can be made. In the context of PV, measurement uncertainties propagate into energy yield uncertainty, which in turn culminates into financial risk associated with an investment. This risk increases the cost of a PV installation. The aim of this thesis is to contribute towards the reduction of PV related measurement uncertainties. This is done in two ways. One is via developing and utilising more comprehensive methodologies for uncertainty propagation of complex measurands. The other is via more detailed estimates of the uncertainty contributors. In particular, the areas addressed in this thesis are the uncertainty estimation of the temperature coefficient measurements of modules; the uncertainty estimation of energy rating and module performance ratio measurements; and the uncertainties due to spectral effects on measurements performed with a flash solar simulator. The reported deviation in measurements of the temperature coefficients of P_MAX of modules is in the order of ±10% to ±15%. This is larger than the difference in the temperature coefficients of modules of the same type. The first step to improving the deviation between measurements is to estimate the uncertainty in a robust way. It was identified that there was no accepted approach of doing this. These measurements are strongly correlated, which complicates the uncertainty estimates. For the sake of simplicity, previously correlations have been avoided and conservative estimates used instead. In this work, uncertainties in both temperature and power and their correlations are estimated and propagated into the overall temperature coefficient uncertainty. Furthermore, temperature coefficients were calculated via weighing the measurements with their associated uncertainties. This was done for five different measurement setups that represent the majority of setups used worldwide. The approach was validated with measurement intercomparison of two modules measured on all systems. The approach reduced the overall uncertainty by half compared to the previous conservative estimates. It was demonstrated that uncertainties as low as 3% are achievable. The improved uncertainty estimates enabled the identification of a systematic effect due to a class B spectrum. This work culminated in the lowest reported measurement deviation of ±3.2% for module P_MAXtemperature coefficient measurements that was within the stated measurement uncertainties. The clear benefit of accounting for correlations was extended to measurements at different irradiance conditions and into the calculation of module performance ratio and energy rating. This was done via defining all the correlations between measurements and then propagating them with Monte Carlo simulations. The simulations are done with samples of a multivariate normal distribution with a variance-covariance matrix that corresponds to the estimated measurement correlations. It is demonstrated that both the energy rating and module performance ratio uncertainties strongly depend on the correlation estimates and that they cannot be conservatively overestimated. The module performance ratio uncertainty can be significantly lower than the measurement uncertainty at STC. This is because of the additional knowledge encoded into the selection of the underlying model used for calculating the energy rating. Therefore, the significance of the choice of model in the upcoming standard has been highlighted. It was confirmed that both bilinear interpolation and the proposed climatic datasets could be used for energy rating, but there are some areas that may need further investigation. An alternative way of improving uncertainty estimates and in turn reducing the associated uncertainty is via a more detailed characterisation of the uncertainty sources. A key uncertainty source is due to spectral effects in flash solar simulators. To better quantify this source, a complementary device was built to monitor the spectrum. The device is based on a matrix of photodiodes with commercially available interference filters situated on top and custom designed data acquisition electronics. This device is used in conjunction with the spectroradiometer to estimate the effects of flash-variation on the spectrum, the spectral temporal stability of the flash and spectral uniformity of the simulator and the attenuation masks used for altering the irradiance levels. It was demonstrated that the spectrum changes significantly during the flash and between flashes. While this effect is partially corrected for via the monitoring cell, it introduces additional uncertainty for non c-Si modules. This uncertainty is minimised by changes in the operational procedures. The spectral non-uniformity of the attenuation masks was shown to be significant, i.e. as large as 4%, in the NIR, prompting further investigation of the additional uncertainty for non c-Si modules. In this work, the methodology of estimating and propagating correlations in PV related measurements and the benefits of doing so are demonstrated. It is also highlighted that the uncertainty due to spectral effects goes beyond the uncertainty of spectroradiometer measurements. Finally, it is shown how they can be estimated with a complementary spectral monitor.

The present study evaluated the utility of the methods outlined in the Promoting the Emergence of Advanced Knowledge Relational Training System Equivalence Module (PEAK-E) through a single-case evaluation. Validity, reliability, and effectiveness were the variables explored to assess the degree to which the assessment was able to identify appropriate skills for targeted intervention, and the degree to which the programs were efficacious in teaching the targeted skills. Baseline results suggested that the programs identified through the PEAK-E assessment were not within the participants’ repertoires prior to the intervention. Following the implementation of 9 programs across three participants with autism, mastery was achieved for all of the directly trained relations, and all targeted derived relations emerged for 8 of the 9 programs

A presente Tese de Doutorado apresenta uma análise de diversos fatores que influenciam nos resultados da caracterização elétrica de módulos fotovoltaicos e na obtenção de seus principais parâmetros. A principal análise refere-se aos efeitos que ocorrem ao traçar a curva I-V (corrente versus tensão) de um módulo fotovoltaico decorrentes da rapidez e da direção da varredura (de Isc para Voc e vice-versa) utilizada na tensão de polarização necessária para traçar a curva I-V. Quando a caracterização elétrica é realizada com tempo de varredura reduzido, como por exemplo, em simuladores solares pulsados, há desvios significativos nos resultados, dependendo da tecnologia de fabricação do módulo fotovoltaico. Também é analisada a importância do fator de descasamento espectral no resultado da caracterização elétrica de módulos fotovoltaicos. Uma comparação entre os resultados dos valores dos coeficientes térmicos determinados com simulador solar (indoor) e sob iluminação natural (outdoor) é realizada, concluindo-se que são equivalentes dentro do intervalo de incerteza das medidas. Finalmente é apresentada uma comparação entre medidas realizadas sob iluminação natural e com simulador solar, levando-se em conta os fatores investigados na tese, isto é, os efeitos decorrentes da rapidez da varredura de tensão, da medida da temperatura do módulo e do descasamento espectral no momento da caracterização. / This doctoral thesis presents an analysis of several issues that influences the electrical characteristics of photovoltaic modules and its parameters. The main analysis is about sweep time effects that arise due to the speed and direction (Isc to Voc and vice versa) used to polarize the module in order to trace the I-V curve. A fast voltage sweep, as used in pulsed solar simulators, can cause discrepancies in the results of some photovoltaic module technologies. It is also analyzed the importance of the spectral mismatch factor in the characterization of photovoltaic devices. A comparison of indoor and outdoor measurements of thermal coefficients is performed and it is concluded that they are equivalent and the results are equivalent among the experimental uncertainties. Finally a comparison between indoor and outdoor measurements of photovoltaic modules is presented where it is discussed the issues studied in the thesis, i.e., sweep time effects, temperature measurement and spectral mismatch factor.

I projektet dimensionerades ett tre våningar högt flerbostadshus i KL-trämoduler med utgångspunkt från dagens byggande av moduler som främst görs i träregelstommar. Vägg- och bjälklagsdimensioner beräknades och ritades upp. Metoder för infästningar och lyft av moduler med träregelstommar undersöktes genom intervjuer och applicerades i den mån som är möjlig för KL-trämoduler. Syftet var att ta fram en konstruktionsutformning för moduler av KL-trä avsedda för bostadsbyggande. Utformningen skall principiellt även kunna användas för andra liknande byggnader. Dimensioneringen visade att KL-träskivorna klarar av lasterna med god marginal. Avgörande för vägg- och bjälklagstjockleken var branddimensioneringen. Infästningar mellan olika byggnadsdelar kan göras på liknande sätt med KL-trä som med träregelstomme. Metoden att använda sig av stålförband i form av vinkelbeslag eller spikplåtar kan användas till de båda stomalternativen. Modullyft kan i viss mån utföras på samma sätt i de båda stommarna. / A three storey tall building was used as a reference object in this project and dimensioned with a starting point from timber frame modular constructions. Wall and floor dimensions are calculated and drawn. Methods for attachment and lifting of modules are examined through interviews and are, when possible, applied for the CLT modules. The purpose of this project was to design CLT modules intended for residential use. The goal of the design was that it can be used in similar buildings. The calculations showed that the fire requirements were the decisive factor when deciding the thickness of the walls and floors. Attachments between different building parts can be designed similarly in both timber frame modules and CLT modules. The method of using angle irons and nail plates is possible for both timber frame and CLT. The lifting of the modules can to some extent be executed similarly for the two frameworks.

abstract: This is a two-part thesis. Part 1 of this thesis investigates the influence of spatial temperature distribution on the accuracy of performance data of photovoltaic (PV) modules in outdoor conditions and provides physical approaches to improve the spatial temperature distribution of the test modules so an accurate performance data can be obtained in the field. Conventionally, during outdoor performance testing, a single thermocouple location is used on the backsheet or back glass of a test module. This study clearly indicates that there is a large spatial temperature difference between various thermocouple locations within a module. Two physical approaches or configurations were experimented to improve the spatial temperature uniformity: thermally insulating the inner and outer surface of the frame; backsheet and inner surface of the frame. All the data were compared with un-insulated conventional configuration. This study was performed in an array setup of six modules under two different preconditioning electrical configurations, Voc and MPPT over several clear sunny days. This investigation concludes that the best temperature uniformity and the most accurate I-V data can be obtained only by thermally insulating the inner and outer frame surfaces or by using the average of four thermocouple temperatures, as specified in IEC 61853-2, without any thermal insulation. Part 2 of this thesis analyzes the field data obtained from old PV power plants using various statistical techniques to identify the most influential degradation modes on fielded PV modules in two different climates: hot-dry (Arizona); cold-dry (New York). Performance data and visual inspection data of 647 modules fielded in five different power plants were analyzed. Statistical tests including hypothesis testing were carried out to identify the I-V parameter(s) that are affected the most. The affected performance parameters (Isc, Voc, FF and Pmax) were then correlated with the defects to determine the most dominant defect affecting power degradation. Analysis indicates that the cell interconnect discoloration (or solder bond deterioration) is the dominant defect in hot-dry climate leading to series resistance increase and power loss, while encapsulant delamination is being the most dominant defect in cold-dry climate leading to cell mismatch and power loss. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2015