Waste management is something that affects most people. Thewaste amounts are still increasing, but the waste treatment ischanging towards recycling and integrated solutions. In Swedenproducers’responsibility for different products, a taxand bans on deposition of waste at landfills implicates areorganisation of the municipal solid waste management. Plansare made for new incineration plants, which leads to that wastecombustion comes to play a role in the reorganisation of theSwedish energy system as well. The energy system is supposed toadapt to governmental decisions on decommission of nuclearplants and decreased use of fossil fuels. Waste from private households consists of hazardous waste,scrap waste, waste electronics and wastes that to a largeextent are generated in the kitchen. The latter type has beenstudied in this thesis, except for newsprint, glass- and metalpackages that by source separation haven’t ended up in thewaste bin. Besides the remaining amount of the above mentionedfractions, the waste consists of food waste, paper, cardboard-and plastic packages and inert material. About 80-90 % of thismixed household waste is combustible, and the major part ofthat is also possible to recycle. Several systems analyses of municipalsolid waste managementhave been performed. Deposition at landfill has been comparedto energy recovery, recycling of material (plastic andcardboard) and recycling of nutrients (in food waste).Environmental impact, fuel consumption and costs are calculatedfor the entire lifecycle from the households, until the wasteis treated and the by-products have been taken care of. To stop deposition at landfills is the most importantmeasure to take as to decrease the environmental impact fromlandfills, and instead use the waste as a resource, therebysubstituting production from virgin resources (avoidingresource extraction and emissions). The best alternative tolandfilling is incineration, but also material recycling andbiological treatment are possible. Recycling of plastic has slightly less environmental impactand energy consumption than incineration. The difference issmall due to that plastic is such a small part of the totalwaste amount, and that just a small part of the collectedamount is recycled. Cardboard recycling is comparable toincineration; there are both advantages and disadvantages.Source separation of food waste may lead to higher transportemissions due to intensified collection, but severalenvironmental advantages are observed if the waste is digestedand the produced biogas substitutes diesel in busses.Composting has no environmental advantages compared toincineration, mainly due to lack of energy recovery. Therecycling options are more expensive than incineration. Theincreased cost must be seen in relation to the environmentalbenefits and decreased energy use. If the work with sourceseparation made by the households is included in the analysis,the welfare costs for source separation and recycling becomesnon-profitable. It is however doubted how much time is consumedand how it should be valuated in monetary terms. In systems analyses, several impacts are not measured.Environmental impact has been studied, but not allenvironmental impact. As the parts of the system are underconstant change, the results are not true forever. Recyclingmay not be unambiguously advantageous today, but it can be inthe future. Despite the fact that systems analysis has been developedduring 10 years in Sweden, there are still many decisions takenregarding waste management without support from systemsanalysis and use of computer models. The minority of users ispleased with the results achieved, but the systems analysis isfar from easy to use. The adaptation of tools and models to thedemands from the potential users should consider thatorganisations of different sizes have shifting demands andneeds. The application areas for systems analysis and models arestrategic planning, decisions about larger investments andeducation in universities and within organisations. Systemsanalysis and models may be used in pre-planning procedures. Apotential is a more general application (Technology Assessment)in predominantly waste- and biofuel based energy processes, butalso for assessment of new technical components in a systemsperspective. The methodology and systems approach developedwithin the systems analysis has here been transformed to anassessment of environmental, economic and technical prestandaof technical systems in a broad sense.

The zinc metalloprotease neprilysin (NEP) has been shown to degrade small bioactive peptides. Crystal structures of seven NEP-inhibitor complexes and biochemical characterization of NEP activity have highlighted amino acid interactions that are crucial to ligand binding. Studies also indicate that NEP is one of a select group of metalloenzymes that degrade the amyloid-beta peptide (Aß) in vivo and in situ. Accumulation of neurotoxic Aß aggregates in the brain appears to be a causative agent in the pathophysiology of Alzheimer's Disease (AD). For this reason the enzymatic degradation of Aß has been studied extensively, but little is known about specific binding interactions underlying NEP degradation of Aß. Using known crystal structures of NEP, we have conducted comparative computational studies of ligand binding that predict NEP residues Arg 102 and 110 form binding interactions specific to Aß. These interactions may provide insight for using NEP degradation of Aß in AD therapy. / Bayer School of Natural and Environmental Sciences; / Chemistry and Biochemistry; / MS; / Thesis;

<p>Waste management is something that affects most people. Thewaste amounts are still increasing, but the waste treatment ischanging towards recycling and integrated solutions. In Swedenproducers’responsibility for different products, a taxand bans on deposition of waste at landfills implicates areorganisation of the municipal solid waste management. Plansare made for new incineration plants, which leads to that wastecombustion comes to play a role in the reorganisation of theSwedish energy system as well. The energy system is supposed toadapt to governmental decisions on decommission of nuclearplants and decreased use of fossil fuels.</p><p>Waste from private households consists of hazardous waste,scrap waste, waste electronics and wastes that to a largeextent are generated in the kitchen. The latter type has beenstudied in this thesis, except for newsprint, glass- and metalpackages that by source separation haven’t ended up in thewaste bin. Besides the remaining amount of the above mentionedfractions, the waste consists of food waste, paper, cardboard-and plastic packages and inert material. About 80-90 % of thismixed household waste is combustible, and the major part ofthat is also possible to recycle.</p><p>Several systems analyses of municipalsolid waste managementhave been performed. Deposition at landfill has been comparedto energy recovery, recycling of material (plastic andcardboard) and recycling of nutrients (in food waste).Environmental impact, fuel consumption and costs are calculatedfor the entire lifecycle from the households, until the wasteis treated and the by-products have been taken care of.</p><p>To stop deposition at landfills is the most importantmeasure to take as to decrease the environmental impact fromlandfills, and instead use the waste as a resource, therebysubstituting production from virgin resources (avoidingresource extraction and emissions). The best alternative tolandfilling is incineration, but also material recycling andbiological treatment are possible.</p><p>Recycling of plastic has slightly less environmental impactand energy consumption than incineration. The difference issmall due to that plastic is such a small part of the totalwaste amount, and that just a small part of the collectedamount is recycled. Cardboard recycling is comparable toincineration; there are both advantages and disadvantages.Source separation of food waste may lead to higher transportemissions due to intensified collection, but severalenvironmental advantages are observed if the waste is digestedand the produced biogas substitutes diesel in busses.Composting has no environmental advantages compared toincineration, mainly due to lack of energy recovery. Therecycling options are more expensive than incineration. Theincreased cost must be seen in relation to the environmentalbenefits and decreased energy use. If the work with sourceseparation made by the households is included in the analysis,the welfare costs for source separation and recycling becomesnon-profitable. It is however doubted how much time is consumedand how it should be valuated in monetary terms.</p><p>In systems analyses, several impacts are not measured.Environmental impact has been studied, but not allenvironmental impact. As the parts of the system are underconstant change, the results are not true forever. Recyclingmay not be unambiguously advantageous today, but it can be inthe future.</p><p>Despite the fact that systems analysis has been developedduring 10 years in Sweden, there are still many decisions takenregarding waste management without support from systemsanalysis and use of computer models. The minority of users ispleased with the results achieved, but the systems analysis isfar from easy to use. The adaptation of tools and models to thedemands from the potential users should consider thatorganisations of different sizes have shifting demands andneeds.</p><p>The application areas for systems analysis and models arestrategic planning, decisions about larger investments andeducation in universities and within organisations. Systemsanalysis and models may be used in pre-planning procedures. Apotential is a more general application (Technology Assessment)in predominantly waste- and biofuel based energy processes, butalso for assessment of new technical components in a systemsperspective. The methodology and systems approach developedwithin the systems analysis has here been transformed to anassessment of environmental, economic and technical prestandaof technical systems in a broad sense.</p>

This research is about liquid-liquid chromatography modelling. While the main focus was on liquid-liquid chromatography, where the stationary and mobile phases are both liquid, theory of different types of chromatography, including the currently most used techniques, were considered as well. The main goal of this research was to develop a versatile liquid-liquid separation model, able to model all potential operating scenarios and modes of operation. A second goal was to create effective and usable interfaces to such a model, implying primarily information visualisation, and secondarily educative visualisation. The first model developed was a model based on Counter-Current Distribution. Next a new more elemental model was developed, the probabilistic model, which better models continuous liquid-liquid chromatography techniques. Finally, a more traditional model was developed using transport theory. These models were used and compared to experimental data taken from literature. The models were demonstrated to model all main liquid-liquid chromatography techniques, incorporated the different modes of operation, and were able to accurately model many sample components and complex sample injections. A model interface was developed, permitting functional and effective model configuration, exploration and analysis using visualisation and interactivity. Different versions of the interface were then evaluated using questionnaires, group interviews and Insight Evaluation. The visualisation and interactivity enhancements have proven to contribute understanding and insight of the underlying chromatography process. This also proved the value of the Insight Evaluation method, providing valuable qualitative evaluation results desired for this model interface evaluation. A prototype of a new graphical user interface developed, and showed great potential for combining model parameter input and exploring the liquid-liquid chromatography processes. Additionally, a new visualisation method was developed that can accurately visualise different modes of operation. This was used to create animations, which were also evaluated. The results of this evaluation show the new visualisation helps understanding of the liquid-liquid chromatography process amongst CCC novices. The model software will be a valuable tool for industry for predicting, evaluating and validating experimental separations and production processes. While effective models already existed, the use of interactive visualisation permits users to explore the relationship between parameters and performances in a simpler yet more powerful way. It will also be a valuable tool for academia for teaching & training, both staff and students, on how to use the technology. Prior to this work no such tool existed or existing tools were limited in their accessibility and educational value.

The research presented in this thesis is aimed at developing a limit state design methodology for railway track for recommendation to Standards Australia's next revision of the 'Permanent way materials: prestressed concrete sleepers' code (AS1085.14, 2003). There is widespread suspicion that the railway track, particularly concrete sleepers, have untapped reserves of strength that has potential engineering and economic advantages for track owners. Through quantifying the effects of train speed, wheel impact loadings and distribution of vehicle loads, track engineers would be able to design railway track more accurately and hence uncover the reserves of strengths in railway track. To achieve this improvement a comprehensive set of wheel/rail impact measurements has been collected over a one year period to establish a distribution of track loadings. The wheel/rail impact data collected showed a logarithmically linear distribution which shows that impact forces are randomly occurring events. The linearity of the data also allows for wheel/rail impact forces to be forecasted allowing for a more rational risk based design of the railway track. To help with an investigation of the influence of changes to train operation on the wheel/rail impact force distributions, development of a new dynamic track computer model capable of simulating the complex interaction between the train and track was completed within this research. The model known as DTRACK (Dynamic analysis of rail TRACK) was benchmarked against other dynamic models and field data to validate its outputs. The field measurements and DTRACK simulations became the basis for development of a limit state design methodology for railway track (risk based approach) for railway track in place of an allowable limit state (compliance based) approach. This new approach will allow track owners to assess the track capacity based on more realistic loads and is expected to allow an increase in the capacity of existing track infrastructure which will allow railways to be more commercially competitive and viable.

<p> A computer model is developed to simulate the emulsion copolymerization of styrene/butadiene in perfectly stirred batch, semi-batch or continuous flow reactors. The model considers free radical initiation by a redox mechanism, micellar particle nucleation, radical concentration as -a function of particle size, radical entry rate and termination rate and diffusion controlled termination and propagation reactions. It predicts conversion, copolymer composition, particle number, number and mass average molecular masses and tri- and tetra-functional branch frequencies. A simple method of estimating the particle size distribution is included in the model. Heat balances over the reactor and cooling jacket are considered and proportional-integra control of the reactor temperature is simulated.</p> <p> The model is used to simulate SBR copolymerization and styrene homopolymerization experimental data from the literature. These simulations tested only certain parts of the model and it is concluded that a more complete verification of the model can only be achieved by running a series of designed experiments. Qualitatively, the molecular mass, particle size distribution and reactor temperature predictions appear to be reasonable. The lack of appropriate temperature dependent rate constants currently limits the molecular mass predictions to isothermal conditions.</p> <p> A comparison of semi-batch operating policies designed to control copolymer composition is presented to illustrate the potential application of the model.</p> / Thesis / Master of Engineering (ME)

This thesis deals with the development of an Airspace Sector Occupancy Model (ASOM). The model determines the occupancy of Air Traffic Control Center (ARTCC) sectors for a given geometry of sectors and flight schedules, and can be used to study the impact of alternative flight schedules on the workload imposed on the sectors. Along with complimentary airspace analysis models, this can serve as an advisory tool to approve flight plans in the Free Flight Scenario, or to reschedule flights around a Special Use Airspace (SUA). ASOM is developed using Matlab 5.2, and can be run on an IBM compatible PC, Macintosh, or Unix Workstation. The computerized model incorporates the powerful features of graphics and hierarchical modeling inherent in Matlab, to design an effective tool for analyzing air traffic scenarios and their respective sector occupancies. / Master of Science

No description available.

This dissertation presents novel methodologies in the field of stochastic computer model calibration and uncertainty quantification. Simulation models are widely used in studying physical systems, which are often represented by a set of mathematical equations. Inference on true physical system (unobserved or partially observed) is drawn based on the observations from corresponding computer simulation model. These computer models are calibrated based on limited ground truth observations in order produce realistic predictions and associated uncertainties. Stochastic computer model differs from traditional computer model in the sense that repeated execution results in different outcomes from a stochastic simulation. This additional uncertainty in the simulation model requires to be handled accordingly in any calibration set up. Gaussian process (GP) emulator replaces the actual computer simulation when it is expensive to run and the budget is limited. However, traditional GP interpolator models the mean and/or variance of the simulation output as function of input. For a simulation where marginal gaussianity assumption is not appropriate, it does not suffice to emulate only the mean and/or variance. We present two different approaches addressing the non-gaussianity behavior of an emulator, by (1) incorporating quantile regression in GP for multivariate output, (2) approximating using finite mixture of gaussians. These emulators are also used to calibrate and make forward predictions in the context of an Agent Based disease model which models the Ebola epidemic outbreak in 2014 in West Africa. The third approach employs a sequential scheme which periodically updates the uncertainty inn the computer model input as data becomes available in an online fashion. Unlike other two methods which use an emulator in place of the actual simulation, the sequential approach relies on repeated run of the actual, potentially expensive simulation. / Doctor of Philosophy / Mathematical models are versatile and often provide accurate description of physical events. Scientific models are used to study such events in order to gain understanding of the true underlying system. These models are often complex in nature and requires advance algorithms to solve their governing equations. Outputs from these models depend on external information (also called model input) supplied by the user. Model inputs may or may not have a physical meaning, and can sometimes be only specific to the scientific model. More often than not, optimal values of these inputs are unknown and need to be estimated from few actual observations. This process is known as inverse problem, i.e. inferring the input from the output. The inverse problem becomes challenging when the mathematical model is stochastic in nature, i.e., multiple execution of the model result in different outcome. In this dissertation, three methodologies are proposed that talk about the calibration and prediction of a stochastic disease simulation model which simulates contagion of an infectious disease through human-human contact. The motivating examples are taken from the Ebola epidemic in West Africa in 2014 and seasonal flu in New York City in USA.

Agent-based simulation models are an important tool to study the effectiveness of policy interventions on the uptake of residential photovoltaic systems by households, a cornerstone of sustainable energy system transition. In order for these models to be trustworthy, they require rigorous validation. However, the canonical approach of validating emulation models through calibration with parameters that minimize the difference of model results and reference data fails when the model is subject to many stochastic influences. The residential photovoltaic diffusion model PVact features numerous stochastic influences that prevent straightforward optimization-driven calibration. From the analysis of the results of a case-study on the cities Dresden and Leipzig (Germany) based on three error metrics (mean average error, root mean square error and cumulative average error), this research identifies a parameter range where stochastic fluctuations exceed differences between results of different parameterization and a minimization-based calibration approach fails. Based on this observation, an approach is developed that aggregates model behavior across multiple simulation runs and parameter combinations to compare results between scenarios representing different future developments or policy interventions of interest.