Development of an extended environmental multimedia modeling system (EEMMS)

All pollutant contamination problems have both short and long term impacts on ambient air, water, and soil environments. Previous environmental pollution control programmes mainly focused on a single environmental medium (e.g., groundwater). Traditional environmental multimedia models (EMM) usually simulate pollutants' fate and transport in separate zones, based on one-dimensional, first-order mechanisms. This may lead to biased results and simulation errors. In this study, firstly, a new extended environmental multimedia model system (EEMMS) was set up, which includes four sub-modules (sources, air quality, unsaturated zone, groundwater) on a regional spatial-temporal scale. Three different approaches were evaluated for solving multi-dimensional coupled pollutants equations using experimental data from the literature: a) EEMMS/FEM (numerical finite element method); b) EEMMS /FDM (numerical finite difference method); and, c) EEMMS /analytical method. Furthermore, three validations related to the three approaches are conducted. First, experimental results from a pilot scale landfill were used to verify the spatial temporal accuracy of predicted emission fluxes and concentrations in both numerical spatial and temporal scale. Further systematic model validations were implemented and tested comparing with the dual domain mass transfer model and 2-D analytical model. Complicated 3-D real site validation was conducted through the Trail Road Sanitary Landfill site. 3-D reasonable results have been obtained through the comparisons of analytical and numerical solutions (FDM and FEM) in non-uniform and unsteady conditions. Implementing the EEMMS/FEM solution in the above three validations was found to be better than that of EEMMS/FDM, and EEMMS /analytical solutions. EEMMS/FEM solution also provided more stabilization technique, a better mesh that minimizes the error or even a faster solution. In addition, given a large amount of uncertainties associated with EMMS practices, sensitivity analyses approach such as retardation factor, Peclet number (Pe), hydraulic conductivity, bulk density, porosity, were embedded into the developed EEMMS. Lastly, the new EEMMS model containing both new environmental multimedia system (EMS) and Monte Carlo Method (MCM) was developed to an integrated tool for the risk assessment of contaminants. The new EEMMS would serve as a risk assessment tool to address the fate and transport of the pollutants in complex, multimedia environments and subsequently to help in the management of the resulting environmental impacts

Early wildfire detection by air quality sensors on unmanned aerial vehicles: Optimization and feasibility

“Millions of acres of forests are destroyed by wildfires every year, causing ecological, environmental, and economical losses. The recent wildfires in Australia and the Western U.S. smothered multiple states with more than fifty million acres charred by the blazes. The warmer and drier climate makes scientists expect increases in the severity and frequency of wildfires and the associated risks in the future. These inescapable crises highlight the urgent need for early detection and prevention of wildfires. This work proposed an energy management framework that integrated unmanned aerial vehicle (UAV) with air quality sensors for early wildfire detection and forest monitoring. An autonomous patrol solution that effectively detects wildfire events, while preserving the UAV battery for a larger area of coverage was developed. The UAV can send real-time data (e.g., sensor readings, thermal pictures, videos, etc) to nearby communications base stations (BSs) when a wildfire is detected. An optimization problem that minimized the total UAV’s consumed energy and satisfied a certain quality-of-service (QoS) data rate were formulated and solved. More specifically, this study optimized the flight track of a UAV and the transmit power between the UAV and BSs. Finally, selected simulation results that illustrate the advantages of the proposed model were proposed”--Abstract, page iii

Étude CFD du système de ventilation d'une chambre d'hôpital pour réduire les infections et atteindre le confort thermique

RÉSUMÉ : Dans la conception des bâtiments modernes, les systèmes de climatisation occupent un rôle central. Les systèmes de climatisation sont conçus en tenant compte des deux exigences essentielles aux habitats humains : le confort thermique et la qualité de l'air. Satisfaire ces deux exigences devient de plus en plus difficile surtout dans le contexte de nombreuses maladies aéroportées telles que la SARS-Covid-19. Le but de cette recherche numérique est de simuler différentes conceptions de ventilation avec trois débits 9, 12, et 15 ACH (nombre de changements d'air par heure) pour un modèle de chambre d'hôpital, tout en tenant compte des recherches antérieures. L'objectif ici est d'illustrer comment le réglage du débit d'air et le placement des diffuseurs peuvent affecter le confort thermique et l'élimination des polluants contenant principalement le dioxyde de carbone. Les équations de RANS (Reynolds Averaged Navier Stokes) avec le modèle de turbulence k-e, ont été utilisées comme modèle mathématique pour le flux d'air. Les conditions aux limites ont été extraites des références de ventilation de l'ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers Society) et des études antérieures. Contrairement à la croyance populaire, les données ont montré que l'augmentation de la ventilation n'améliorait pas nécessairement la distribution de l'air ou n'éliminait pas plus de polluants. L'élimination des polluants est fortement affectée par l'emplacement de l'exutoire. Selon le confort thermique, il existe une corrélation entre le débit d'air, la position de l'entrée et l'intensité de la turbulence. Il a été constaté que le cas à débit 9 ACH et le cas à débit 12 ACH présentaient la meilleure élimination des polluants. De plus, le confort thermique obtenu dans les deux derniers cas était le meilleur parmi les cas étudiés même si la cible n'a pas été atteinte. Il est à noter que pour ces deux cas, la sortie est située sous le niveau de la tête du patient, et l'air est introduit près du plafond sur le mur opposé. -- Mot(s) clé(s) en français : Confort thermique, Qualité de l'air, Simulation CFD, Chambre d'isolement, Élimination des contaminants. -- ABSTRACT : The main requirement in designing air conditioning systems is to provide thermal comfort to occupants. In addition, the elimination of pollution is one of the crucial health elements in building design, particularly in the presence of many airborne diseases such as Covid-19 lately. The purpose of this numerical research is to simulate various ventilation designs for a hospital room model by taking into account results obtained by previous researchers. Four designs with three flow rates 9, 12, and 15 ACH (Air Change per Hour), were applied to each. The objective is to determine the effect of airflow and the diffuser location distribution on the thermal comfort and pollutants elimination represented by carbon dioxide. Through SolidWorks Flow Simulation software, Reynold Averaged Navier Stokes (RANS) equations, along with the k-e turbulence model are used as the underlying mathematical model for the airflow. In addition, boundary conditions are extracted from ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers Society) ventilation publications and from relevant literature. Contrary to popular belief, the results of this study have demonstrated that the increase in ventilation does not necessarily improve air distribution or remove more contaminants. In addition, pollutant removal has been significantly affected by the outlet's location. Furthermore, a correlation has been deduced for thermal comfort between airflow, diffuser locations, and turbulence intensity. It has been found that case four at flow 9 ACH and case five at flow 12 ACH had the optimum removal of the contaminants. Although thermal comfort is not totally achieved inside the room, still the latter two cases are the best of the 12 cases. It is noteworthy to mention that for these two cases, the outlet is located below the level of the patient's head, and the air is supplied near the ceiling on the opposite wall. However, thermal comfort has not been entirely achieved in the occupied area too. -- Mot(s) clé(s) en anglais : Thermal Comfort, Air Quality, CFD Simulation, Isolation Room, Contaminant Removal

Pathways for the Oxidation of Sarin in Urban Atmospheres

Terrorists have threatened and carried out chemicalhiological agent attacks on targets in major cities. The nerve agent sarin figured prominently in one well-publicized incident. Vapors disseminating from open containers in a Tokyo subway caused thousands of casualties. High-resolution tracer transport modeling of agent dispersion is at hand and will be enhanced by data on reactions with components of the urban atmosphere. As a sample of the level of complexity currently attainable, we elaborate the mechanisms by which sarin can decompose in polluted air. A release scenario is outlined involving the passage of a gas-phase agent through a city locale in the daytime. The atmospheric chemistry database on related organophosphorus pesticides is mined for rate and product information. The hydroxyl,radical and fine-mode particles are identified as major reactants. A review of urban air chernistry/rnicrophysics generates concentration tables for major oxidant and aerosol types in both clean and dirty environments. Organic structure-reactivity relationships yield an upper limit of 10-1' cm3 molecule-' S-* for hydrogen abstraction by hydroxyl. The associated midday loss time scale could be as little as one hour. Product distributions are difficult to define but may include nontoxic organic oxygenates, inorganic phosphorus acids, sarin-like aldehydes, and nitrates preserving cholinergic capabilities. Agent molecules will contact aerosol surfaces in on the order of minutes, with hydrolysis and side-chain oxidation as likely reaction channels

A national method for predicting environmental pollution

Area based prediction methods are developed for the noise indices LAeq, LA10 and LA90 and winter and annual measures of sulphur dioxide air pollution concentrations. The research examines the relationships between these pollutant variables and a number of key demographic predictor variables. The demographic variables considered include: - traffic density - road network density and - land use for predicting noise and - land use and, - whether an area is subject to smoke control for predicting sulphur dioxide concentrations. Data from the National Survey of Smoke and Sulphur Dioxide, a noise survey of Milton Keynes, Bexley and the West Midland regions and noise data supplied by Open University undergraduate students studying the course T234 'Environmental Control and Public Health' have been used to calibrate and test the proposed theoretical prediction models partially. Two forms of prediction model are presented namely prediction matrices and linear multivariate regression models. The main findings of the research are: 1. That LAeq, LA10 and LA90 can be predicted using industrial land use and traffic density but there are regional differences in noise which are unaccounted for by these variables. 2. That the variability of noise (LA10 - LA90) is related to traffic density. 3. Measures of sulphur dioxide are related to both land use and whether an area is subject to a smoke control order and there are no significant regional differences unaccounted for by these predictor variables (East Anglia excluded). Regression equations are presented which predict sulphur dioxide concentrations with accuracies of between ±1.84 µg/m3 and ±4.36 µg/m3. However, the results from the detailed study of the Midland, North East and North West regions indicate that there is an interaction between the region and smoke control variables. 4. The ratio of Smoke/SO2 is related to whether of not an area is subject to smoke control

Development of an Installation to Emulate Altitude, Ambient Temperature, and Ambient Humidity on Thermal Engines. Application to the Study of the Impact over E6 Engine Performance

[ES] Las normativas cada vez más restrictivas sobre las emisiones contaminantes de los vehículos de motor impuestas por la Unión Europea han obligado a los fabricantes de equipos originales (OEM) a proporcionar a los centros de investigación herramientas e instalaciones que pueden reproducir de forma precisa y repetida diferentes condiciones atmosféricas durante las primeras etapas del desarrollo del motor. En la actualidad la legislación europea incluye pruebas de emisiones reales en conducción (RDE) en diferentes condiciones atmosféricas, con altitudes de hasta 1300 metros sobre el nivel del mar y temperaturas que alcanzan los -7 ºC. Esto se ha hecho típicamente utilizando cámaras climáticas y altimétricas que permiten la reproducción de las condiciones atmosféricas en toda la celda de prueba, y más recientemente conectando a motor simuladores de altitud acoplados con unidades de tratamiento de aire (AHU). En esta Tesis Doctoral, se presenta la mejora del simulador de altitud comercializado por la empresa HORIBA denominado MEDAS, utilizando procedimientos tanto inductivos como deductivos, con el objetivo de ampliar el rango de prestaciones de la instalación, así como mejorar la precisión del control de la presión del aire comburente y reducir el consumo energético global. Además, durante esta fase, se lleva a cabo el desarrollo de un modelo 1D del simulador de altitud, con el que es posible obtener resultados precisos sobre el desempeño de la instalación para diferentes condiciones de contorno, como puede ser el punto operativo del motor, la presión de la sala o la temperatura del agua de refrigeración. A continuación, se han desarrollado dos nuevos equipos: el Módulo de Temperatura del MEDAS (MTM) y el Módulo de Humedad del MEDAS (MHM); mejorando las estrategias de control y algunos componentes clave (por ejemplo, la columna de agua de burbujas) para controlar con precisión la temperatura y la humedad del aire de combustión. Estos dos junto con el MEDAS crean un simulador de atmósfera completo, que permite el control independiente de las tres variables psicrométricas del aire de combustión del motor: presión, temperatura y humedad. Por último, el simulador de atmósfera desarrollado se utiliza para estudiar el efecto que las tres variables psicométricas del aire ambiente tienen sobre el rendimiento y las emisiones contaminantes de un motor Diesel Euro 6 turboalimentado, demostrando el gran efecto que tiene la humedad ambiental sobre las emisiones contaminantes de los motores Diesel y la necesidad de considerar este parámetro en las estrategias de calibración. Algunos resultados obtenidos podrían ser la reducción de potencia que el motor sufre al operar en condiciones de altitud, los cambios que la temperatura ambiente causa en el punto de operación del turbo grupo o como las emisiones de NOx se reducen cuando la humedad ambiente aumenta.[CA] Les normatives cada vegada més restrictives sobre les emissions contaminants dels vehicles de motor imposades per la Unió Europea han obligat als fabricants d'equips originals (OEM) a proporcionar als centres d'investigació eines i instal·lacions que poden reproduir de manera precisa i repetida diferents condicions atmosfèriques durant les primeres etapes del desenvolupament del motor. En l'actualitat la legislació europea inclou proves d'emissions reals en conducció (RDE) en diferents condicions atmosfèriques, amb altituds de fins a 1300 metres sobre el nivell de la mar i temperatures que aconsegueixen els -7 °C. Això s'ha fet típicament utilitzant cambres climàtiques i altimètriques que permeten la reproducció de les condicions atmosfèriques en tota la cel·la de prova, i més recentment connectant a motor simuladors d'altitud acoblats amb unitats de tractament d'aire (AHU). En aquesta Tesi Doctoral, es presenta la millora del simulador d'altitud comercialitzat per l'empresa HORIBA denominat MEDAS, utilitzant procediments tant inductius com deductius, amb l'objectiu d'ampliar el rang de prestacions de la instal·lació així com millorar la precisió del control de pressió de l'aire de combustió i reduir el consum energètic global. A més, durant aquesta fase, es du a terme el desenvolupament d'un model 1D del simulador d'altitud, amb el qual és possible obtindre resultats precisos sobre l'acompliment de la instal·lació per a diferents condicions de contorn, com pot ser el punt d'operació del motor, l'altitud d'instal·lació o la temperatura de l'aigua de refrigeració. A continuació, s'han desenvolupat dos nous equips: el Mòdul de Temperatura del MEDAS (MTM) i el Mòdul d'Humitat del MEDAS (MHM); millorant les estratègies de control i alguns components clau (per exemple, la columna d'aigua de bambolles) per a controlar amb precisió la temperatura i la humitat de l'aire de combustió. Aquests dos juntament amb el MEDAS creen un simulador d'atmosfera complet, que permet el control independent de les tres variables psicromètriques de l'aire de combustió del motor: pressió, temperatura i humitat. Finalment, el simulador d'atmosfera desenvolupat s'utilitza per a estudiar l'efecte que les tres variables psicomètriques de l'aire ambient tenen sobre el rendiment i les emissions contaminants d'un motor Dièsel Euro 6 *turboalimentado, demostrant el gran efecte que té la humitat ambiental sobre les emissions contaminants dels motors Dièsel i la necessitat de considerar aquest paràmetre en les estratègies de calibratge. Alguns resultats obtinguts podrien ser la reducció de potència que el motor pateix en operar en condicions d'altitud, els canvis que la temperatura ambient causa en el punt d'operació del turbo grup o com les emissions de NOx es redueixen quan la humitat ambiente augmenta.[EN] Increasingly restrictive regulations on pollutant emissions for motor vehicles imposed by the European Union have forced original equipment manufacturers (OEMs) to provide research centers with tools and facilities that can accurately and repeatedly reproduce different atmospheric conditions during the early stages of engine development. Nowadays, the European legislation includes real driving emissions (RDE) tests at different atmospheric conditions, with altitudes up to 1300 meters above sea level and temperatures reaching -7 ºC. This has been done typically using altimetric and climatic chambers, which allow the reproduction of the atmospheric conditions in the whole test cell. More recently, connecting to the engine altitude simulators coupled with air handling units (AHU). In this Ph.D. Thesis, the improvement of the altitude simulator commercialized by the company HORIBA called MEDAS, carried out by inductive and deductive procedures, is presented to extend the installation's performance range, improve the combustion air pressure control accuracy, and reduce the installation global energy consumption. Furthermore, during this phase, the development of a 1D model of the altitude simulator is carried out, with which it is possible to obtain accurate results about the performance of the installation for different boundary conditions such as the engine operation point, the room pressure, or the cooling water temperature. Following, two new pieces of equipment have been developed: MEDAS Temperature Module (MTM) and MEDAS Humidity Module (MHM), improving the control strategies and some key components (i.e., the bubbles water-column) to increase the accuracy of the combustion air temperature and humidity control. Together with the MEDAS, these two create a complete atmosphere simulator, which allows the independent control of the three psychrometric variables of the engine combustion air: pressure, temperature, and humidity. Lastly, the atmosphere simulator developed is used to study the effect that the three psychometric variables of the ambient air have on the performance and the pollutant emissions of a Euro 6 turbocharged diesel engine, proving the significant effect that the ambient humidity has on the diesel engines pollutant emissions and the necessity of considering this parameter in the calibration strategies. Some results could be the reduction in power that the engine suffers when operating in altitude conditions, the changes that the ambient temperature causes at the turbocharger operative point, or the decrease in NOx emissions that happen when the ambient humidity increases.Tabet Aleixandre, R. (2022). Development of an Installation to Emulate Altitude, Ambient Temperature, and Ambient Humidity on Thermal Engines. Application to the Study of the Impact over E6 Engine Performance [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/183753TESI

Accidents caused by hazardous materials released in an urban environment: a numerical and experimental approach.

This research studies the transport and dispersion of hazardous materials after a fire accident in an urban setting and the unpredictable threats provoked for the population and the environment. A fire accident may result, inter alia, from industrial activity or during the transportation of hazardous materials, such as diesel, petrol or kerosene liquids. In the current research, mineral oil pool fire accidents are examined in order to define the toxic smoke zones at different urban scale geometries. Three different urban scale geometries are examined: a) an isolated building, b) a street canyon and c) a staggered array of urban blocks. The fluid flow, the hazardous dispersion and the safety limits are studied using the Computational Fluid Dynamics (CFD) techniques and wind tunnel experiments. The Computational simulations were conducted using the CFD solver of Fluent and the Fire Dynamic Simulator (FDS). Both Reynolds-average Navier-Stokes (RANS) modes and Large Eddy Simulations (LES) methods were applied. Wind tunnel experiments were conducted in order to better understand the flow around these geometries and evaluate them with LES models. The numerical models were validated with wind tunnel experiments and with additional experimental data selected from the bibliography. The numerical results defined the toxic smoke limits and allowed the creation of simplified risk maps. The latter can define the mitigation measures after a fire accident.PhD in Aerospac