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Multiple problems caused by urban runoff have emerged as a consequence to the continuing development of urban areas in recent decades. The increase of impervious land areas can significantly alter watershed hydrology and water quality. Typical impacts to downstream hydrologic regimes include higher peak flows and runoff volumes, shorter concentration times, and reduced infiltration. Urban runoff increases the transport of pollutants and nutrients and thus degrades water bodies adjacent to urban areas. One of the most frequently used practices to restore the hydrology and water quality of urban watersheds is bioretention (also known as a rain garden). Despite its wide applicability, an understanding of its multiple physiochemical and biological treatment processes remains an active research area. To provide a wide ability to evaluate the hydrologic input to bioretention systems, spatial and temporal distribution of storm events in Virginia were studied. Results generated from long-term frequency analysis of 60-year precipitation data demonstrate that the 90 percentile, or 10-year return period rainfall depth and dry duration in Virginia are between 22.9 – 35.6 mm and 15.3 – 25.8 days, respectively. Monte-Carlo simulations demonstrated that sampling programs applied in different regions would likely encounter more than 30% of precipitation events less than 2.54 mm, and 10% over 25.4 mm. Further experimental research was conducted to evaluate bioretention recipes for retaining stormwater nitrogen (N) and phosphorus (P). A mesocosm experiment was performed to simulate bioretention facilities with 3 different bioretention blends as media layers with underdrain pipes for leachate collection. A control group with 3 duplicates for each media was compared with a replicated vegetated group. Field measurement of dissolved oxygen (DO), oxidation-reduction potential (ORP), pH, and total dissolved solids (TDS) was combined with laboratory analyses of total suspended solids (TSS), nitrate (NO3), ammonium (NH4), phosphate (PO4), total Kjeldahl nitrogen (TKN) and total phosphorus (TP) to evaluate the nutrient removal efficacies of these blends. Physicochemical measurements for property parameters were performed to determine characteristics of blends. Isotherm experiments to examine P adsorption were also conducted to provide supplementary data for evaluation of bioretention media blends. The results show that the blend with water treatment residuals (WTR) removed >90% P from influent, and its effluent had the least TDS / TSS. Another blend with mulch-free compost retained the most (50 – 75%) total nitrogen (TN), and had the smallest DO / ORP values, which appears to promote denitrification under anaerobic conditions. Increase of hydraulic retention time (HRT) to 6 h could influence DO, ORP, TKN, and TN positively. Plant health should also be considered as part of a compromise mix that sustains vegetation. Two-way analysis of variance (ANOVA) found that single and interaction effects of HRT and plants existed, and could affect water quality parameters of mesocosm leachate. Based upon the understanding of the physiochemical and hydrologic conditions mentioned previously, a design model of a bioretention system became the next logical step. The computational model was developed within the Matlab® programming environment to describe the hydraulic performance and nutrient removal of a bioretention system. The model comprises a main function and multiple subroutines for hydraulics and treatment computations. Evapotranspiration (ET), inflow, infiltration, and outflow were calculated for hydrologic quantitation. Biomass accumulation, nitrogen cycle and phosphorus fate within bioretention systems were also computed on basis of the hydrologic outputs. The model was calibrated with the observed flow and water quality data from a field-scale bioretention in Blacksburg, VA. The calibrated model is capable of providing quantitative estimates on flow pattern and nutrient removal that agree with the observed data. Sensitivity analyses determined the major factors affecting discharge were: watershed width and roughness for inflow; pipe head and diameter for outflow. Nutrient concentrations in inflow are very influential to outflow quality. A long-term simulation demonstrates that the model can be used to estimate bioretention performance and evaluate its impact on the surrounding environment. This research advances the current understanding of bioretention systems in a systematic way, from hydrologic behavior, monitoring, design criteria, physiochemical performance, and computational modeling. The computational model, combined with the results from precipitation frequency analysis and evaluation of bioretention blends, can be used to improve the operation, maintenance, and design of bioretention facilities in practical applications. / Ph. D.

Η παρούσα έρευνα πραγματοποιήθηκε στο Εργαστήριο Ρευστομηχανικής και Εφαρμογών Αυτής του Τμήματος Μηχανολόγων και Αεροναυπηγών Μηχανικών του Πανεπιστημίου Πατρών και χρηματοδοτήθηκε από το πρόγραμμα «Ηράκλειτος ΙΙ» στα πλαίσια του Επιχειρησιακού Προγράμματος Εκπαίδευση και Δια Βίου Μάθησης, Επένδυση στη κοινωνία της γνώσης. Ο έλεγχος του θερμικού φορτίου στη λειτουργία διαφόρων μηχανολογικών ή ηλεκτρολογικών συστημάτων από συστήματα ψύξης, γίνεται όλο και πιο αναγκαίος στη σημερινή εποχή. Τα συστήματα ψύξης κατηγοριοποιούνται σε ενεργά, που μεταφέρουν ενέργεια υπό μορφή αισθητής θερμότητας μέσω ενός υγρού και σε παθητικά συστήματα ψύξης που χρησιμοποιούν τη λανθάνουσα θερμότητα εξάτμισης του ρευστού λειτουργίας που κυκλοφορεί στην εγκατάσταση, εξαιτίας των τριχοειδών δυνάμεων που αναπτύσσονται από την ύπαρξη πορώδους υλικού. Τα παθητικά συστήματα ψύξης προτιμώνται έναντι των ενεργών, καθώς έχουν τη δυνατότητα να απάγουν περισσότερη θερμότητα, παρουσιάζουν πιο αξιόπιστη λειτουργία, εξαιτίας της έλλειψης κινητών μερών και τέλος, εμφανίζουν μεγαλύτερη διάρκεια ζωής. Μία διάταξη που προσφέρει δυνατότητες ελέγχου του θερμικού φορτίου είναι το κύκλωμα τριχοειδούς αντλίας, Capillary Pump Loop (CPL), που αποτέλεσε και το αντικείμενο μελέτης στην παρούσα διδακτορική διατριβή. Αξιοποιεί τις τριχοειδείς δυνάμεις που αναπτύσσονται στη διεπιφάνεια υγρής-αέριας φάσης του ρευστού λειτουργίας στο πορώδες υλικό που περικλείει ο εξατμιστής στο εσωτερικό του, καθώς και τη λανθάνουσα θερμότητα εξάτμισης και συμπύκνωσης του ρευστού. Με τον τρόπο αυτό, επιτυγχάνει την κυκλοφορία του ρευστού λειτουργίας στην εγκατάσταση, χωρίς την παρουσία μηχανικής αντλίας, και τη μεταφορά των απαιτούμενων θερμικών φορτίων σε μεγάλες αποστάσεις. Ένα κύκλωμα τριχοειδούς αντλίας αποτελείται από έναν εξατμιστή, ένα συμπυκνωτή, τις γραμμές υγρού και ατμού καθώς και ένα ρεζερβουάρ. Από τη μέχρι τώρα έρευνα είχαν μελετηθεί πειραματικά αρκετά μοντέλα CPL, δίνοντας ιδιαίτερη έμφαση στη διαδικασία εκκίνησης της διάταξης καθώς και στις συνθήκες μόνιμης λειτουργίας. Σε όλα αυτά τα μοντέλα το θερμικό φορτίο επιβάλλονταν μέσω ηλεκτρικών αντιστάσεων. Στην παρούσα διερεύνηση η διάταξη ενσωμάτωσε τη δυνατότητα η προσφερόμενη θερμότητα να παρέχεται και από την ηλιακή ακτινοβολία αναπτύσσοντας έναν εργαστηριακό ηλιακό προσομοιωτή. Προκειμένου να βελτιώσουμε τη συγκέντρωση της ακτινοβολίας και να επιτύχουμε υψηλότερη θερμοκρασία στον εξατμιστή του CPL χρησιμοποιήθηκε παραβολικό κάτοπτρο σε συνδυασμό με συγκεντρωτικό συλλέκτη. Η πειραματική εγκατάσταση που σχεδιάσθηκε και κατασκευάστηκε είχε ως στόχο τη μελέτη της συμπεριφοράς του CPL σε θερμικά φορτία υπό μεταβλητές συνθήκες πλήρωσης της εγκατάστασης, ενώ εξετάστηκε και η συμπεριφορά της τριχοειδούς αντλίας όταν ο εξατμιστής βρίσκονταν υπό κλίση ως προς το επίπεδο, και έγινε σύγκριση των πειραματικών αποτελεσμάτων που προέκυψαν με τα αντίστοιχα για λειτουργία σε οριζόντιο επίπεδο. Η παραμετροποίηση της πειραματικής διερεύνησης του CPL αφορούσε τέσσερις τιμές θερμοκρασίας εισόδου του ρευστού, 15, 25, 35 και 45 οC, τρεις τιμές πίεσης πλήρωσης του κυκλώματος, 0,05, 0,15 και 0,25 bar, και, τέλος, τρεις γωνίες κλίσης, 8ο, 16ο και 23ο. Η διάρκεια των πειραμάτων ήταν αρχικά δέκα ώρες, ώστε να προσομοιώνει τη λειτουργία της εγκατάστασης σε διάστημα ηλιοφάνειας κατά τη διάρκεια της καλοκαιρινής περιόδου, αλλά και εικοσιτέσσερις, ώστε να αποτυπωθεί η απρόσκοπτη διατήρηση της κατάστασης σταθερής λειτουργίας του κυκλώματος. Στο δεύτερο μέρος της διατριβής παρουσιάζονται τα υπολογιστικά μοντέλα δύο και τριών διαστάσεων, 2Δ και 3Δ, όπως σχεδιάστηκαν στο λογισμικό GAMBIT της Fluent Inc., βάση των διαστάσεων του εξατμιστή της πειραματικής εγκατάστασης. Τα αποτελέσματα της διερεύνησης που πραγματοποιήθηκε αφορούσαν το νερό, την ακετόνη, την αμμωνία σαν ρευστά λειτουργίας, τόσο στο επίπεδο όσο και υπό γωνίες κλίσης, παραμετροποιώντας τόσο το θερμαινόμενο μήκος πορώδους επί του συνολικού μήκους του πορώδους του εξατμιστή, όσο και τη θερμοκρασία κορεσμού. Τα δεδομένα για όλα τα ρευστά συγκεντρώθηκαν σε συγκριτικά διαγράμματα, ώστε να εξαχθούν συμπεράσματα για τα περιθώρια αξιοποίησης αυτών, είτε υπάρχει κλίση είτε όχι. Επιπλέον, τεκμηριώθηκε η επιλογή του νερού σαν καταλληλότερο ρευστό λειτουργίας κάτω από δεδομένες συνθήκες. Στο τρίτο μέρος παρουσιάζεται ο αριθμητικός κώδικας που δημιουργήθηκε για τη μοντελοποίηση ολόκληρης της εγκατάστασης του CPL και παραθέτουμε συγκριτικά διαγράμματα, για τις ίδιες συνθήκες λειτουργίας, με τα πειραματικά, τα αριθμητικά και τα υπολογιστικά αποτελέσματα. Στο τελευταίο μέρος έχουμε σχεδιάσει κυκλώματα, αξιοποιώντας την τριχοειδή αντλία, για τη ψύξη/θέρμανση των χώρων μιας κατοικίας για ολόκληρο το έτος. Μια πρόταση που βασίζεται στην αξιοποίηση της ηλιακής ενέργειας και ανταποκρίνεται στην επιτακτική ανάγκη για εκμετάλλευση των ανανεώσιμων πηγών ενέργειας και τη μείωση της χρήσης ηλεκτρικής ενέργειας, εξοικονομώντας χρήματα και προστατεύοντας το περιβάλλον / Present research was conducted in Fluid Mechanics Laboratory of the Mechanical Engineering and Aeronautics Department, University of Patras, and was financed by the operational programme «Herakleitos II», Education and Lifelong Learning Investing in knowledge society. Modern demands in controlling heating load of the cooling systems of mechanical or electrical components are increasing. Cooling systems are divided in active and passive systems. In active systems energy is transported due to sensual heat. While in passive systems due to working fluid latent heat of evaporation because of capillary forces developed in the porous wick inside the evaporator. Passive systems are preferred compared to active systems because they can transfer larger amount of heat, are more reliable, since there are no moving parts, and, finally, lifetime period is longer. The Capillary Pumped Loop (CPL) is a device proper for thermal management control, and was investigated in the present PhD study. The CPL operating principle is based on capillary action, developed in the liquid-vapor phase interface of the working liquid in the porous wick inside the evaporator, and working fluid evaporation and condensation latent heat. The result is that the working fluid is displaced inside the loop without any mechanical pump and heat load is transported in large distances. CPL main components are an evaporator, a condenser, a liquid line, a vapor line and a reservoir. Research regarding the CPL experimental models so far concentrated in the evaporator start-up and steady working state conditions. For all those cases heat load was applied through electric resistances. In the present study heat load was alternatively applied through solar radiation using a solar simulator, designed for this purpose. In order to achieve higher temperature in the evaporator external wall and increase solar radiation exploited, a parabolic mirror was used in combination with a solar collector. The experimental installation was designed in such a way to study the behavior of a CPL when heat load was imposed under different loop charging pressures and for several evaporator inclination angles. Experimental results where compared to the results acquired for evaporator operating at zero inclination angle. The initial values of the working fluid temperature were 15, 25, 35 and 45 oC, of the charging pressure 0,05, 0,15, 0,25 bar and of the inclination angle 8, 16 and 23o. The duration of the experiments was initially ten hours, in order to simulate CPL operating during a typical summer day, and then increased to twenty four hours to investigate continuous operation during all day. In the second section of this study two and three dimensions, 2D and 3D, computational models are presented designed in Gambit, Fluent Inc., based on the exact dimensions of the experimental ones. Computational results were derived for water, acetone and ammonia, as working fluid, for zero inclination and the three values of angles mentioned above. Models were customized for different porous wick heated length and working liquid of different saturation temperature. Comparative figures for all working fluids are presented whether evaporator was under inclination angle or not. Moreover, those comparative figures reviled that water was more suitable as working fluid under steady operating state. In the third section the numerical model simulating the overall CPL function is presented and comparative figures between experimental, computational and numerical results are given, for the same operating conditions. In the last section a potential solar CPL heating/cooling system for domestic use is presented. This potential system could meet the demands for using renewable energy sources in order to reduce electrical energy consumption, save money and protect the environment at the same time.

The glenohumeral joint is the most dislocated joint in the body due to the lack of bony constraints and dependence on soft tissue, primarily muscles and ligaments, to stabilize the joint. The goal of this study was to develop a computational model of the glenohumeral joint whereby joint behavior was dictated by articular contact, ligamentous constraints, muscle loading, and external perturbations. Validation of this computational model was achieved by comparing predicted results from the model to the results of a cadaveric experiment in which the relative contribution of muscles and ligaments to anterior joint stability was examined. The results showed the subscapularis to be critical to stabilization in both neutral and external rotations, the biceps stabilized the joint in neutral but not external rotation, and the inferior glenohumeral ligament resisted anterior displacement only in external rotation. Knowledge gained from this model could assist in pre-operative planning or the design of orthopedic implants. Use of this model as a companion to cadaveric testing could save valuable time and resources.

Made available in DSpace on 2017-07-21T14:19:23Z (GMT). No. of bitstreams: 1 Albino Szesz Junior.pdf: 2551855 bytes, checksum: ad2fa2da3cef74797c4e91a3da0e453b (MD5) Previous issue date: 2015-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this work is to present the SEMEARE, a methodology for defining periods of sowing of crops, with four stages, including planning, modeling, experimentation and decision making. At the planning stage the goals and strategies for defining the sowing periods are defined and analyzed the agricultural context of the study area. In the modeling stage, the simulation models are set to be used, sowing dates and other necessary data. After system modeling and simulations performed are obtained yield values, germination time, number of days to harvest, among others, for each specific date. At the trial stage analysis of the information and you can set the best times for sowing culture defined and then make decision making. For validation, the methodology we used the MarkSimGCM a climate data simulator, to generate daily weather data, and the DSSAT, Version 4.5, using CERES-Maize model to simulate growth of corn. The simulation was applied to a hypothetical maize cultivar with average maturity characteristics in a real location (S25 ° 09'18.70 "W 50 ° 05'15.65"),with planting carried out under rainfed conditions, sowing depth 5 cm spacing planting 20 cm between seeds and 50 cm between plant rows and plant population: 10 plants / m2. Thus the DSSAT addresses the data of corn, while the MarkSimGCM simulates weather data for use in DSSAT in creating a weather station with daily data of maximum and minimum temperature, precipitation and solar radiation between 2011 and 2014. We simulated in 29 different sowing dates in Vintage 2011-2012, 2012- 2013, 2013-2014. From this income was generated graphs, maturation cycle,information used in decision making. This research resulted in the development of a generic methodology, which enables the use of different simulation models of crops and climate data, interacting with different systems of decision support as agricultural. / O objetivo desta dissertação é apresentar a SEMEARE uma metodologia para definição de períodos de semeadura de culturas agrícolas, com quatro etapas, incluindo planejamento, modelagem, experimentação e tomada de decisão. Na etapa de planejamento são definidos os objetivos e estratégias para definição dos períodos de semeadura, bem como analisado o contexto agrícola da área de estudo. Na etapa de modelagem são definidos os modelos de simulação a serem utilizados, datas de semeadura e demais dados necessários. Após a modelagem do sistema e executadas as simulações são obtidos os valores de rendimento, tempo de germinação, número de dias para colheita, entre outros, para cada data definida. Na etapa de experimentação são analisadas as informações sendo possível definir os melhores períodos de semeadura para a cultura definida e, então, realizar a tomada de decisão. Para validação, a metodologia utilizou-se do MarkSimGCM, um simulador de dados climáticos, para geração de dados climáticos diários, e o DSSAT, Versão 4.5, através do Modelo CERES-Maize, para simulação de crescimento da cultura do milho. A simulação foi aplicada em um cultivar hipotético do milho com características de maturidade média, em uma localização real (S25°09'18.70" W50°05'15.65"), com plantio realizado em condições de sequeiro, profundidade de semeadura 5 cm, espaçamento de plantio 20 cm entre sementes e 50 cm entre linhas de plantio e população de plantas: 10 plantas/m2. Dessa forma o DSSAT aborda os dados da cultura do milho, enquanto o MarkSimGCM simula dados climáticos para serem utilizados no DSSAT na criação de uma estação meteorológica com dados diários de temperatura máxima e mínima, precipitação e radiação solar entre 2011 e 2014. Foram realizadas simulações em 29 diferentes datas de semeadura, nas Safras 2011- 2012, 2012-2013, 2013-2014. A partir disso gerou-se gráficos de rendimento, ciclo de maturação, informações utilizadas na tomada de decisão. Esta pesquisa resultou no desenvolvimento de uma metodologia genérica, a qual possibilita a utilização de diferentes modelos de simulação de culturas agrícolas e de dados climáticos, interagindo com diferentes sistemas de apoio a decisão no âmbito agrícola.

Chapter 1 presents a mini-review of the prominent theoretical models which are employed in the prediction of the outcome of organic chemical reactions. The chapter covers the most widely used empirical and semi-empirical models, as well as some more recently developed models. Most have a common theme in that they were developed using electrophilic aromatic substitution as a model reaction. Chapter 2 describes the development of a predictive model based on the average local ionisation energy. The model is shown to be of use in predicting both the regioselectivity and relative reactivity of a wide range of molecules in electrophilic aromatic substitution reactions. An attempt is made to expand the model beyond electrophilic aromatic substitution to various other electrophilic reactions. Chapter 3 details the investigation into the predicted enhancement of reactivity of aromatic rings. Calculations of electrostatic surface potential surfaces show that the proximity of an electron rich atom to an aromatic ring increases the electron density of the ring. Analysis of the local ionisation energy surfaces of these molecules suggests that the reactivity of these rings towards electrophiles is also increased. Preliminary studies on model systems using NMR spectroscopy aim to determine whether this effect can be observed experimentally. Chapter 4 introduces a method for applying the average local ionisation energy to nucleophilic reactions. The ability of the model to predict the regiochemical outcome and relative reaction rates of various molecules is examined in a variety of reaction types, including nucleophilic aromatic substitution. Chapter 5 reports studies into the polarisation-induced cooperative effects that exist between hydrogen bonding groups. The cooperative effect has been measured quantitatively in some simple hydroxybenzene derivatives. An improved understanding of this effect, developed using small molecule models, should lead to an improved ability to predict the extent of this effect in larger systems.

Investigating the arrangement of the packed DNA inside the nucleus has revealed the essential role of genome organisation in controlling genome function. Furthermore, genome architecture is highly dynamic and significant chromatin re-organisation occurs in response to environmental changes. However, the mechanisms that drive the 3D organisation of the genome remain largely unknown. To understand the effect of biophysical properties of chromatin on the dynamics and structure of chromosomes, I developed a 3D computational model of the nucleus of the yeast S. cerevisiae during interphase. In the model, each chromosome was a hetero-polymer informed by our bioinformatics analysis for heterogeneous occupancy of chromatin-associated proteins across the genome. Two different conditions were modelled, normal growth (25°C) and heat shock (37°C), where a concerted redistribution of proteins was observed upon transition from one temperature to the other. Movement of chromatin segments was based on Langevin dynamics and each segment had a mobility according to their protein occupancy and the expression level of their corresponding genes. The model provides a significantly improved match with quantitative microscopy measurements of telomere positions, the distributions of 3D distances between pairs of different loci, and the mean squared displacement of a labelled locus. The quantified contacts between chromosomal segments were similar to the observed Hi-C data. At both 25°C and 37°C conditions, the segments that were highly occupied by proteins had high number of interactions with each other, and the highly transcribed genes had lower contacts with other segments. In addition, similar to the experimental observations, heat-shock genes were found to be located closer to the nuclear periphery upon activation in the simulations. It was also shown that the determined distribution of proteins along the genome is crucial to achieve the correct genome organisation. Hence, the heterogeneous binding of proteins, which results in differential mobility of chromatin segments, leads to 3D self-organisation.