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Silva, Ana Margarida Barradinhas da. "Heat recovery from wastewater: numerical modelling of sewer systems." Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/8473.
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Dissertação para obtenção do Grau de Mestre em
Engenharia do Ambiente, perfil Engenharia SanitáriaThis thesis was carried as a collaboration of Delft University of Technology (TU Delft) and the companies Waternet and KWR. The main project aims to study the possibility of thermal energy recovery from wastewater, reducing the carbon dioxide (CO2) emissions linked to the energy sector. The present work is based on a previous computational model that was developed to simulate heat recovery from wastewater for constant flow rate and temperature of water. The first goal is to simulate a wastewater discharge. In order to achieve this, a Gaussian function was added to the boundary conditions for water flow rate and water temperature. As a second goal, this work aims to assess the significance of the terms present in the water heat balance and air heat balance equations. Binary coefficients were added in each term of both equations and then all the combinations were computed. The unsteady situation successfully simulated a main discharge and numerical predictions for water temperature and flow rate are presented. The deviations associated with the modified cases for the two equations suggest that the heat flux pipe to water (!!") and heat flux pipe to air (!!") terms are crucial for water and air heat balance predictions,respectively. In order to smooth extra oscillations, the time step (dt) was reduced and a smaller relative size of oscillations was obtained. This work concludes with a section of future developments in order to improve the results obtained. Despite of the fact that the current state of these routines does not allow us to accurately assess heat exchanges in pipes, promising results were obtained, proving that numerical modelling of heat recovery will contribute greatly to the development of the main project.
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Moregård, Daniel. "Heat Maps : En metod för att uvärdera banor." Thesis, Högskolan i Skövde, Institutionen för kommunikation och information, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-6357.
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Denna rapport har undersökt om game metrics genom heat maps kan användas för att hitta en choke point i en bana gjord till spelet Team Fortress 2. Game metrics och kvantitativa metoder erbjuder ett objektivt och nästan automatiserat alternativ till kvalitativa metoder när det kommer till balansering. En bana har konstruerats med en choke point och har speltestats för att generera en heat map. För att undersöka om det går att hitta en choke point med hjälp av en heat map så har en enkät gjorts där respondenter bads hitta choke pointen med hjälp av den heat mapen som genererades från speltestningen av banan. Alla respondenter lyckades hitta mitten av choke pointen med hjälp av heat mapen. I framtiden skulle arbetet kunna utökas genom att undersöka om användandet av bottar eventuellt skulle helt kunna automatisera balanseringsprocessen. Det skulle också gå att undersöka hur olika klasser rör sig i en bana.
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Mählkvist, Simon, and Netzell Pontus. "Pulp mill heat and mass balance model : Exploring the benefits and possibilities of process modelling as an applied method in a case study." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-41292.
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This thesis focused on the modelling of a pulping process. The purpose was to see if an accurate model can be crated based on relatively simple premises and if the errors can be identified or analysed. To realise this, the authors conducted a literature study to identify the current state of the art regarding the chemical pulping process. In addition, flow charts and sample data from a case study were examined. Based on the literature review and case study, model assumptions were derived. The model is divided into sixteen components. Where mixing occurs, lumped conditions are assumed. The model has five validation points, four of which are temperatures and a mass flowrate. These are shown as deviations from the measured values. In conclusions, it was the model could produce stable results over a narrow time frame. More so if the transition period at the start of the simulation is overlooked. Several new model assumptions are presented with the purpose to increase accuracy e.g. account for the components ability to store mass.
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Domingues, Catia Motta, and Catia Domingues@csiro au. "Kinematics and Heat Budget of the Leeuwin Current." Flinders University. SOCPES, 2006. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20060612.211358.
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This study investigates the upper ocean circulation along the west Australian coast, based
on recent observations (WOCE ICM6, 1994/96) and numerical output from the 1/6 degree Parallel Ocean
Program model (POP11B 1993/97). Particularly, we identify the source regions of the Leeuwin
Current, quantify its mean and seasonal variability in terms of volume, heat and salt transports,
and examine its heat balance (cooling mechanism). This also leads to further understanding of the
regional circulation associated with the Leeuwin Undercurrent, the Eastern Gyral Current and the
southeast Indian Subtropical Gyre.
The tropical and subtropical sources of the Leeuwin Current are understood from an
online numerical particle tracking. Some of the new findings are the Tropical Indian Ocean source
of the Leeuwin Current (in addition to the Indonesian Throughflow/Pacific); the Eastern Gyral
Current as a recirculation of the South Equatorial Current; the subtropical source of the Leeuwin
Current fed by relatively narrow subsurface-intensified eastward jets in the Subtropical Gyre, which
are also a major source for the Subtropical Water (salinity maximum) as observed in the Leeuwin
Undercurrent along the ICM6 section at 22 degrees S.
The ICM6 current meter array reveals a rich vertical current structure near North West
Cape (22 degrees S). The coastal part of the Leeuwin Current has dominant synoptic variability and
occasionally contains large spikes in its transport time series arising from the passage of tropical
cyclones. On the mean, it is weaker and shallower compared to further downstream, and it only
transports Tropical Water, of a variable content. The Leeuwin Undercurrent carries Subtropical
Water, South Indian Central Water and Antarctic Intermediate Water equatorward between
150/250 to 500/750 m. There is a poleward flow just below the undercurrent which advects a
mixed Intermediate Water, partially associated with outflows from the Red Sea and Persian Gulf.
Narrow bottom-intensified currents are also observed.
The 5-year mean model Leeuwin Current is a year-round poleward flow between 22 degrees S and
34 degrees S. It progressively deepens, from 150 to 300 m depth. Latitudinal variations in its volume
transport are a response to lateral inflows/outflows. It has double the transport at 34 degrees S (-2.2 Sv)
compared to at 22 degrees S (-1.2 Sv). These model estimates, however, may underestimate the transport
of the Leeuwin Current by 50%. Along its path, the current becomes cooler (6 degrees C), saltier (0.6 psu)
and denser (2 kg m -3). At seasonal scales, a stronger poleward flow in May-June advects the
warmest and freshest waters along the west Australian coast. This advection is apparently spun up
by the arrival of a poleward Kelvin wave in April, and reinforced by a minimum in the equatorward
wind stress during July.
In the model heat balance, the Leeuwin Current is significantly cooled by the eddy heat
flux divergence (4 degrees C out of 6 degrees C), associated with mechanisms operating at submonthly time scales.
However, exactly which mechanisms it is not yet clear. Air-sea fluxes only account for ~30% of the
cooling and seasonal rectification is negligible. The eddy heat divergence, originating over a narrow
region along the outer edge of the Leeuwin Current, is responsible for a considerable warming of a
vast area of the adjacent ocean interior, which is then associated with strong heat losses to the
atmosphere. The model westward eddy heat flux estimates are considerably larger than those
associated with long lived warm core eddies detaching from the Leeuwin Current and moving
offshore. This suggests that these mesoscale features are not the main mechanism responsible for
the cooling of the Leeuwin Current. We suspect instead that short lived warm core eddies might
play an important role.
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Dantas, Thayse Naianne Pires. "Avaliacao de dados de secagem de suspensoes de polpas de frutas em leito de jorro com alimentacao intermitente." Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15840.
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Previous issue date: 2013-08-08Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
The objective of this work was the development and improvement of the mathematical models based on mass and heat balances, representing the drying transient process fruit pulp in spouted bed dryer with intermittent feeding. Mass and energy balance for drying, represented by a system of differential equations, were developed in Fortran language and adapted to the condition of intermittent feeding and mass accumulation. Were used the DASSL routine (Differential Algebraic System Solver) for solving the differential equation system and used a heuristic optimization algorithm in parameter estimation, the Particle Swarm algorithm. From the experimental data food drying, the differential models were used to determine the quantity of water and the drying air temperature at the exit of a spouted bed and accumulated mass of powder in the dryer. The models were validated using the experimental data of drying whose operating conditions, air temperature, flow rate and time intermittency, varied within the limits studied. In reviewing the results predicted, it was found that these models represent the experimental data of the kinetics of production and accumulation of powder and humidity and air temperature at the outlet of the dryer
O objetivo principal deste trabalho foi o estudo e aperfei?oamento de modelos matem?ticos, baseados em balan?os de massa e de energia, que representem o processo de secagem transiente de polpas de frutas em secador de leito de jorro com alimenta??o intermitente. Os balan?os de massa e de energia para a secagem, representados por um sistema de equa??es diferenciais, foram desenvolvidos em linguagem Fortran e adaptados para a condi??o de alimenta??o intermitente e de ac?mulo de massa no interior do equipamento. Este programa realiza a integra??o deste sistema de equa??es diferenciais utilizando a rotina DASSL (Differential Algebraic System Solver) e o procedimento de estima??o do par?metro do modelo foi fundamentado na minimiza??o da fun??o objetivo da t?cnica de m?nimos quadrados utilizando um m?todo heur?stico de otimiza??o PSO (Particle Swarm Optimization). Utilizando dados experimentais gerados nas pesquisas de secagem de alimentos realizadas nos laborat?rio de Tecnologia de Alimentos e de Sistemas Particulados da UFRN, determinaram-se equa??es emp?ricas estat?sticas e aplicaram-se os modelos referentes aos balan?os para verifica??o da quantidade de ?gua e da temperatura do ar de secagem na sa?da do leito de jorro e da massa de material acumulada no secador. Os modelos foram validados a partir dos dados experimentais de secagens cujas condi??es operacionais, de temperatura do ar, vaz?o da pasta e tempo de intermit?ncia, variavam dentro dos limites estudados. Na an?lise dos resultados preditos, foi constatado que estes modelos representam bem os dados experimentais da cin?tica de produ??o e de ac?mulo de p? e da umidade e da temperatura do ar na sa?da do secado
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Rafiee, Nima. "Process design and energy efficiency analysis of an oil and gas processing plant." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
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The objective of this thesis is process design to prepare a heat and mass balance and associated equipment list that will process untreated reservoir fluids to allow export of saleable gas and oil in an oil and gas processing plant. Gas will be exported to an existing pipeline, oil to a nearby shuttle tanker. By energy efficiency analysis, some energy saving opportunities has been found such as heat integration, replacing control valves with expanders and improving pumps and compressors adiabatic efficiency and then the amount of power recovered through these opportunities have been calculated. After that by considering water added to the feed stream, gas dehydration unit is needed for gas drying. In this reason, a design of TEG dehydration unit has been done and compared with the energy consumption by molecular sieve dehydration unit. Comparison shows that molecular sieve dehydration unit consumes energy about two times more than TEG dehydration unit does. Furthermore, by designing fractionation unit and introducing dividing wall column, consumption of energy decreased about 33% in comparison with conventional columns. In the final part, some energy efficiency opportunities of pumps and compressors, which are the most energy consuming equipment in the oil and gas industries have been introduced. Moreover, the means of power generation for oil and gas plants have been studied. Most plants use gas turbine for power generation and introduce means of increasing gas turbine efficiency and its performance. In the final part some methods for recovery the low-grade heat, variable speed drive which shows significant energy saving, power recovery turbines and reducing friction losses through pipes have been defined.
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Rafaj, Svatomír. "Rotační sušící a sintrovací pece." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-377759.
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This thesis deals with rotary drying and sintering kilns. The first part focused upon construction of the kilns, kiln processes and the options of technological arrangement of the kilns. The thesis second part presents two experiments. The first one is targeted to find the relation between residence time, kiln rotary speed and kiln slope in longitudinal direction. The examinations analysed individually the relation between kiln rotary speed and residence time and the relation between kiln slope and residence time. Finally, the regression equation describing the relation between holding time, kiln rotary speed and kiln rake was established. The results given by regression equation much closer to the real one then the results given by literature. The difference between real residence time and the regression one is about one minute. The second one is concerned with producing a set of equations with respect of mass and heat balance in case of drying process. The input material was wet crushed tetra packs. There were established technological conditions of the material, necessary burner energy input, heat losses and distribution of heat between material and flue gas. There were taken away almost 80 percent of heat energy by flue gases. The remaining 20 percent was divided between latent heat, material and heat losses through the shell of the rotary kiln.
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Oudart, Didier. "Modélisation de la stabilisation de la matière organique et des émissions gazeuses au cours du compostage d'effluents d'élevage." Phd thesis, INSA de Toulouse, 2013. http://tel.archives-ouvertes.fr/tel-00935691.
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Le compostage est un procédé aérobie de stabilisation de la matière organique (MO). Les transformations de la MO conduisent à des émissions gazeuses (NH3, N2O, CH4, CO2) et une perte d'azote utile pour la fertilisation. La variété des pratiques et les différences de nature des substrats modifient la vitesse de dégradation de la MO, la qualité finale du compost produit et la part d'émissions sous forme de polluants gazeux. L'optimisation du procédé nécessite la prédiction de ces transformations ou la réalisation d'essais empiriques. Cette thèse analyse les interactions entre les processus biologiques, biochimiques, physico-chimiques et thermodynamiques majeurs à l'origine de la stabilisation de la MO et des émissions gazeuses de CO2, H2O, NH3, N2O. Elle se focalise sur le compostage par aération passive en andain d'effluents d'élevage. La méthode s'appuie sur la modélisation dynamique, semi-empirique, du procédé et sur des expérimentations sur des andains de petite taille. Dans un premier temps, l'impact des interactions entre les facteurs clés du compostage, soit la biodégradabilité du carbone, la disponibilité de l'azote, l'humidité et la porosité, sur la cinétique et la stœchiométrie des émissions gazeuses est analysé à partir de données acquises en conditions contrôlées et sur une plateforme de compostage à la Réunion sur des périodes allant de 20 à 80 jours. Les facteurs ont été hiérarchisés : l'effet de la porosité couplé à l'effet de l'humidité joue le rôle majeur dans la régulation des transformations de la MO et des émissions gazeuses. Les effets de la porosité, de l'humidité et du type de structurant sur les transformations de la MO, observés en conditions commerciales, confirment les observations en conditions contrôlées. Alors que les écarts de répétabilité en conditions contrôlées sont faibles sur les températures et bilans de masse, ces écarts deviennent élevés en conditions de reproductibilité sur le terrain. Dans un deuxième temps, un modèle dynamique de compostage a été développé simulant la stabilisation du carbone et de l'azote ainsi que les émissions gazeuses de CO2, H2O, NH3 et N2O. Ce modèle est composé de quatre modules couplés. Le premier simule les cinétiques d'oxydation de la MO par une population microbienne hétérotrophe produisant du CO2 et de la chaleur. Le deuxième décrit les échanges thermiques se déroulant lors du compostage, à l'origine de l'aération passive de l'andain et des cinétiques de température interne et d'évaporation d'H2O. Le troisième module décrit le transfert d'oxygène au sein de l'andain modulé par la porosité et l'humidité. Le quatrième module simule les transformations et la stabilisation de l'azote ainsi que les cinétiques d'émissions d'NH3 et de N2O. Le système global représentant un andain de compostage en aération naturelle est considéré comme homogène en termes de composition et de caractéristiques thermiques. Lors de la phase thermophile, le facteur limitant le plus rapidement l'organisation de la MO est la disponibilité de l'azote. L'abaissement de la porosité entraîne une diminution des pertes gazeuses par l'augmentation de l'organisation de la MO. Le fractionnement initial de la MO ainsi que la teneur initiale en biomasse microbienne sont les facteurs clés pour prédire les cinétiques d'organisation du carbone et de l'azote. Les paramètres spécifiques des émissions d'NH3, d'H2O et de N2O sont initialisés en fonction de la nature du substrat et des caractéristiques physiques de l'andain. La calibration du modèle reste à améliorer, et par la suite le modèle devra être validé en condition industrielles. Les effets modélisés de la porosité, de l'humidité et du type de structurant sur les transformations de la MO permettent d'envisager l'usage du modèle pour optimiser le compostage d'effluents d'élevage.
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Gedye, Sharon Jane. "Mass balance in recent peats." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266139.
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Herrero, Miriam Leire. "Heat Balance of a historical church - Solar Heat Gain." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-17152.
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Andersson, Emil. "Online Metallurgical Mass Balance and Reconciliation." Thesis, Umeå universitet, Institutionen för fysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-185252.
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In mineral processing, one of the most important and versatile separation methods is flotation. Flotation utilizes the different surface properties of the valuable minerals in the ore to separate them from the less valuable gangue material in the ore. Crushed and ground ore is mixed with water and fed into flotation tanks. In the flotation tanks, the particles of valuable mineral are made hydrophobic. That way, they can be floated by attaching to air bubbles and gather on top of the flotation tank as froth. This froth, containing higher concentrations of valuable mineral, is recovered and then processed further. The flotation circuit is controlled and maintained using measurements on the mass flows and grades of different materials. Due to economical, practical, and technological limitations, these measurements are performed at a chosen number of points in the circuit and at discrete points in time. Poor measurement data can have devastating consequences if the operators are left with limited information and errors in the circuit remain undetected. The accuracy of the acquired measurements is improved by performing mass balance and reconciliation. Traditionally, mass balance uses the sum of the total mass flows and the average grades over long times to avoid including the internal mass of the circuit in the calculations. It is desirable to perform mass balance directly to allow for faster intervention if any failures occur in the circuit during the on-line process. This report describes an on-line dynamic approach towards mass balancing and reconciliation of the mass flows and grades in a flotation circuit. Here, physical models of the flotation circuit are used to construct mass balance constraints using interpolation and test functions and the mass balance problem is posed as an optimization problem. The optimization problem is to adjust the assay such that the residual, the difference between the measured and the adjusted assay, is minimized while maintaining mass balance. An implementation in MATLAB and tests on synthetic data show that the dynamic formulation of mass balance does adjust 'erroneous' measurements such that mass balance is fulfilled. Given this result, there are still important aspects of the implementation that have to be addressed. The model uses the unknown and cell specific parameters flotation rate and recovery. Thus, these must be found or properly modeled. This report proposes a possible model for flotation rate as well as a strategy to find the recovery. The requirements of accuracy and speed of the implementation are also discussed. Possible next steps of this project is to further confirm a time effective implementation using synthetic data. Consequently, the implementation can be adapted for natural data in order to verify correctness of models.I malmanrikning, är flotation en av de viktigaste och mest mångsidiga metoderna. Flotation utnyttjar de fysikaliska ytegenskaperna som partiklar av värdemineral har för att separera dessa från det mindre värdefulla gråberget i malmen. Krossad och mald malm blandas med vatten och matas in i flotationstankar. I flotationstankarna görs partiklarna av värdemineral hydrofobiska. På så vis kan de fästa sig vid luftbubblor och flyta till ytan och bilda ett skum. Detta skum samlas sedan ihop och behandlas vidare eftersom det innehåller en högre koncentration av värdemineral. Flotationskretsen styrs och underhålls med hjälp av mätningar av massflödena och halterna av de olika ämnena som finns i kretsen. På grund av ekonomiska, praktiska, och teknologiska hinder kan dessa mätningar bara göras på ett utvalt antal punkter i kretsen samt bara vid diskreta tillfällen. Felaktigt data kan ha förödande konsekvenser om operatörerna lämnas med begränsad information och processen fortlöper med oupptäckta fel. Mätsäkerheten kan förbättras med hjälp av massbalansering och haltjustering. Traditionellt görs massbalansering genom att summera den totala massan som löpt genom kretsen samt medelvärden av halterna över lång tid för att undvika att räkna in den interna massan i systemet. Det är önskvärt att utföra massbalansering direkt för att möjliggöra snabbare ingrepp ifall fel uppstår i kretsen under den fortlöpande processen. Denna rapport beskriver en dynamisk lösning för massbalansering och justering av massflöden och halter i en flotationskrets. Här används fysikaliska modeller av kretsen för att konstruera bivillkor för massbalans med hjälp utav interpolation och testfunktioner och massbalanseringsproblemet ställs upp som ett optimeringsproblem. Optimeringen sker genom att justera mätserien så att residualen, skillnaden mellan det uppmätta värdet och det justerade värdet, minimeras under uppfyllande av mass balans. En implementation i MATLAB och tester på syntetisk data visar att den dynamiska formuleringen av massbalans justerar de felaktiga mätvärdena så att massbalans uppfylls. Med det resultatet i åtanke, finns det fortfarande viktiga aspekter av implementationen som bör tas hänsyn till. Modellen använder de okända och cellspecifika parametrarna flotationshastighet och utbytet och dessa måste kunna bestämmas för att denna modell ska kunna användas. Ett förslag på modellering av flotationshastigheten föreslås i rapporten. Dessutom ges förslag på strategier att hitta utbytet. Kraven på noggrannhet och snabbhet diskuteras också. Möjliga nästa steg för projektet är att vidareutveckla en tidseffektiv implementation genom att använda syntetiska data. Därefter kan en implementation för naturligt data verifiera modellerna.
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Khedekar, Mayur. "Temperature Based Estimation of the Time-Resolved Massflux of ICE Exhaust Gas Flow." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-300050.
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The aim ofthe study was to provideinformation and experience gained with fine wire thermocouples (TCs)or resistance wire thermometers (RWTs) temperature signals to estimate the timeresolved heat transfercoefficient. Constant current method was assumed in the study and medium used in this study was air. Here the heat balance equation has been described, different Nucorrelations and further discusses potential hurdles and difficulties one may encounter while calculating heat transfer coefficient. As asolution, the use of an appropriate heatbalance equation and lowpass filter was suggested as this provides a more accurate fitting. The investigation was carried out for Reynolds number (Re) 103 to 107 and Prandlt number (Pr) 0.734. The impact of the Re and Pr on the Nusselts number (Nu) around a cylinder was represented and all the results were compared with GT-POWER engine simulation software.Syftet med studien var att tillhandahålla information och erfarenhet från fina trådtermoelement (TC) eller motståndstrådstermometrar (RWT) temperatursignaler för att uppskatta den tidsupplösta värmeöverföringskoefficienten. Metoden med konstant flöde antogs i studien och mediet som användes i denna studie var luft. Här har värmebalansekvationen beskrivits, olika Nu-korrelationer och diskuterat ytterligare potentiella hinder och svårigheter man kan stöta på vid beräkning av värmeöverföringskoefficienten. Som en lösning föreslogs användning av en lämplig värmebalansekvation och lågpassfilter eftersom detta ger en mer exaktpassform. Undersökningen genomfördes för Reynoldsnummer (Re) 103 till 107 och Prandlt nummer (Pr) 0,734. Effekten av Re och Pr på Nusselts-numret (Nu) runt en cylinder representerades och alla resultat jämfördes med GT-POWER-motorns simuleringsprogram.
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Lauvdal, Anders. "Mass balance model for Hammerfest LNG plant Snøhvit." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-23363.
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The goal of the task is to develop and test a mass balance model for the entire Snøhvit facility which makes it possible to balance all streams inn and out. The model is implemented in an excel sheet. Also production rate calculations for LNG, LPG and condensate are made based on updated well and field data.
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Huss, Matthias. "Past and future changes in glacier mass balance /." Zürich : ETH, 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000256345.
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Schwartz, Vegar. "Greenland ice mass balance using GRACE gravity data." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for bygg, anlegg og transport, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-24543.
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The mass balance of Greenland has been assessed with data from the Gravity Recovery and Climate Experiment (GRACE) satellite mission. Monthly data has been used through the time span of the study; January 2003 - December 2012. Level 2 data from three providers has been used. These are the Jet Propulsion Laboratory (JPL) , GeoForschungsZentrum (GFZ) and the Center for Space Research (CSR). The linear trend in this study points to -181±11 Gt/yr, -172±10 Gt/yr and -183±11 Gt/yr for the three data providers respectively. Notable corrections applied to improve the accuracy of this study are gravity leakage correction, adjustment for post-glacial rebound and non-isotropic smoothing filtering.This master thesis also gives an insight some of the mathematical background of physical geodesy and how this can be applied to use GRACE data to track changes in the gravity field. The methodology of applying this theory is explained in-depth with explanations of some natural assumptions along the way. Results are presented from correction calculations, important secular trend graphs and different time series plots of data from the three data providers. These results are compared to the works of other mentionable authors in the field of polar mass redistribution. Lastly, the thesis enlists some noteworthy strengths and weaknesses of the conducted study. To the author's knowledge, this is the first ice mass loss estimation of Greenland using GRACE level 2 Release 05 data decorrelated by non-isotropic filtering.
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Huss, Matthias Boes Robert. "Past and future changes in glacier mass balance /." Zürich : Versuchsanstalt für Wasserbau, Hydrologie und Glaziologie, ETH Zürich, 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000263371.
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Greenfield, David W. J. "A local authority waste management mass balance model." Thesis, University of Brighton, 2010. https://research.brighton.ac.uk/en/studentTheses/2f7bca16-407c-44d0-a102-d03e3875e542.
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The pressure at the turn of the 21st century for Waste Disposal Authorities to change their waste disposal systems was both urgent and comprehensive, with emphasis being placed on moving towards the 3Rs; Reducing, Recycling and Recovering value from Municipal Wastes. This thesis explores how a mass balance model was created for the Brighton & Hove City and East Sussex County council Private Finance Initiative (PFI) contract, in response to the pressures for change and need for investment up to 2002. An identification and evaluation of the drivers for change at the time has been undertaken; with it being demonstrated that legislation, lack of landfill space and underlying public pressure were the stimulus for change.
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Depoorter, Mathieu A. "Mass balance investigation of Antarctica from budget methods." Thesis, University of Bristol, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.702166.
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During the last 20 years, West Antarctica has experienced enhanced ice discharge to the ocean due to loss of buttressing from melting and collapsing ice shelves. On the other hand, increases in precipitation have been reported in East Antarctica in line with an expected wetter atmosphere in a warming climate. The big questions that still lie ahead are therefore: (i) Will the enhanced precipitations in East Antarctica compensate the dynamic mass losses observed in West Antarctica in the future? (ii) And what will be the resulting contribution to sea level rise (SLR)? To answer those questions we need to have a firm grip on the present day mass balance (MB) of Antarctica and on the mechanisms that govern both the surface mass balance (SMB) and the ice discharge (D) into the ocean. This thesis investigates the MB of Antarctica using the input-output method (10M) allowing for a direct diagnoses of local, regional and global MB in Antarctica. It does this for both the Antarctic Ice Sheet (AIS) and the ice shelves. Because the mass imbalance of AIS is of the order of 5-10% of both accumulation and attrition terms of the mass budget (~2000 Gt yr-1), all glaciers around Antarctica as well as each assumption made require precise attention. This thesis starts with a chapter exploring the grounding zone (Chapter 2), and then goes on to the actual mass balance calculations of the AIS in Chapter 3 and of the Antarctica ice shelves in Chapter 4. The Grounding lines (GL) of Antarctica have been widely studied using various techniques at a local and regional scale. In recent years GL datasets aiming for circumpolar coverage have been published using different approaches. However these datasets still bear unexplained discrepancies of up to tens of kilometres in numerous places around Antarctica. In Chapter 2 four recent datasets are compared which track either the surface break of slope (h) or the inward limit of tidal flexure (F) as proxies for the grounding point (G). From visual examination and from a particle tracking scheme (PTS), it is found that all GL datasets agree within 1-2 km on slow moving ice and on the sides of fast flowing features (FFFs). However it is confirmed that h, obtained from photogrametry or photo clinometry, is not a reliable proxy in central parts of FFFs because of multiple breaks-in-slope and artefacts. It is further confirmed that the most reliable methods to map G in such places are those tracking F. In addition, a gravitational driving stress (td) is computed from a 1 km Antarctic digital model elevation (DEM) and leads to the finding that driving stress mapping (DSM) supports dynamic approaches in grounding line location. This reconciles static and dynamic grounding line methods by showing that they map the same features providing that altimetry is used rather than imagery for static methods. Guided by these analyses a new, up-to-date, and complete grounding line of Antarctica is compiled. The potential of DSM is successfully tested on a grounding line migration case study in West Antarctica. To investigate the grounding zone around Antarctica and its ice dynamics, DSM is further used. DSM allows to map sharp transitions across G for slow moving ice, as well as complicated transitions on fast flowing features (FFFs). Complicated transitions on FFFs contradict the idea of there being an ideal transition occurring at G, whereby the ice flow regime switches from basal drag-dominated to lateral drag-dominated. Rather, it is found that acceleration occurs upstream of G and that deceleration occurs downstream of G. This changes the understanding of the grounding zone ice dynamics, where ice was believed to accelerate at G due to loss of basal drag. Using DSM in combination with ice penetrating radar (lPR), reported and new ice plains (i .e. lightly grounded areas) are detected and mapped. They extents cover ~55,000 km2 around the Ross, the Filchner-Ronne, and the Larsen C ice shelves. These findings have implications for our understanding of ice sheet stability since ice plains are particularly prone to grounding line migration and can stretch up to ~300 km inland of G. In Chapter 3 the MB of the AIS is assessed using the input-output method (lOM). The grounding line fluxes (GLF) and 5MB are estimated for 110 drainage basins covering the whole AIS. The GLF is computed using up to date grounding lines and additional radar ice thicknesses data compared to previous 10M studies. 5MB values are re-evaluated in light of new drainage basins defined from an ice velocity field rather than from topography. 5MB is taken as the 30 years mean of three regional climate models. Due to a number of improvements in the GLF methodology, an unprecedented 94% of the ice sheet area is surveyed, i.e. an increase of + 13% from the latest 10M study. Un-surveyed areas are accounted for using mass trends (MT) from a Bayesian hierarchical modelling solution from the RATES (Resolving Antarctic ice mass TrEndS) project. The integrated AIS mass balance is -63 ± 83 Gt yr- I and divides into -22 ± 28, -62 ± 45, and 22 ± 64 Gt yr- I for the Antarctic Peninsula (AP), the West Antarctic Ice Sheet (WAIS), and the East Antarctic Ice Sheet (EAIS), respectively. The integrated MB is therefore a lower 10M estimate compared to previous 10M studies and reconciles the 10M with the other MB methods of satellite gravimetry and altimetry. Because the stability of the AIS is intimately linked to the stability of ice shelves, Chapter 4 finally focuses on the mass balance of ice shelves around Antarctica, giving the partition between calving fluxes (CF) and basal mass balance (BMB), the main processes by which Antarctic ice is lost. Before this study, iceberg calving had been assumed the dominant cause of mass loss for the Antarctic ice sheet, with previous estimates of the calving flux exceeding 2,000 Gt yr- I . More recently, the importance of melting by the ocean had been demonstrated close to the grounding line and near the calving front. So far, however, no study had reliably quantified the calving flux and the BMB (the balance between accretion and ablation at the ice-shelf base) for the whole of Antarctica. The distribution of fresh water in the Southern Ocean and its partitioning between the liquid and solid phases was therefore poorly constrained. Here, a first estimate of the mass balance components for all ice shelves in Antarctica is produced using calving flux and grounding-line flux from satellite and airborne observations, modelled ice-shelf snow accumulation rates, and a regional scaling that accounts for un-surveyed areas. The total CF is 1321 ± 144 Gt yr- I and the total BMB is -1454 ± 174 Gt yr-1 . These numbers mean that about half of the ice-sheet surface mass gain is lost through oceanic erosion before reaching the ice front, and that the calving flux is about 34% less than previous estimates derived from iceberg tracking. In addition, the fraction of mass loss due to basal processes varies from about 10 to 90 % between ice shelves. A significant positive correlation between BMB and surface elevation change is found for ice shelves experiencing surface lowering and enhanced discharge. It is therefore suggested that basal mass loss is a valuable metric for predicting future ice-shelf vulnerability to oceanic forcing.
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Wiklund, Sara. "Long-term glacier mass balance of Nordenskiöldbreen, Svalbard." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-295789.
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The global warming that’s taking place have an impact over the Earth and the glaciers on Svalbard are undergoing rapid changes as a result. The annual air temperature has been rising on Svalbard since the early 1900’s and in a climate projection expected temperatures continue to rise. The glacial mass balance is important for monitoring glacier response to climate change. In this study the mass balance of Nordenskiöldbreen from 1957 to 2016 is modelled with a temperature-index model. The meteorological data used in the model, precipitation and air temperature, has been measured at a weather station located in Longyearbyen since 1957. The long simulation run makes trends in mass balance, precipitation and air temperature apparent. The mass balance can also be correlated to the temperature and precipitation, which provide important information on how these affect the behavior of glaciers. The results obtained can be used to predict how glaciers change in the future with climate change. In the simulation Nordenskiöldbreen’s mass balance has a negative trend, precipitation doesn’t have any trend and air temperature has a positive trend. The long-term mass balance is controlled by air temperature and the short-term interannual mass balance is caused by precipitation fluctuations.Den globala uppvärmningen som sker just nu har en påverkan över hela jorden och glaciärer på Svalbard genomgår snabba förändringar som följd. På Svalbard har den årliga medeltemperaturen stigit sedan början av 1900-talet och i en klimatprojicering förväntas temperaturen att fortsätta stiga. Den glaciala massbalansen är viktig för att övervaka glaciärers respons till klimatförändringar. I detta arbete modelleras Nordenskiöldbreens massbalans från 1957 till 2016 med hjälp av en temperaturindex modell. Den meteorologiska data som används i modellen, nederbörd och temperatur, har mätts vid en väderstation i Longyearbyen sedan 1957. Med den långa tidsperioden i modellen blir långsiktiga trender i massbalans, nederbörd och temperatur tydliga. Massbalansen kan även korreleras mot temperatur och nederbörd, vilket ger viktig information om hur dessa påverkar glaciärers beteenden. De resultat som framkommer kan användas för att förutspå hur glaciärer förändras i framtiden med en klimatändring. I simuleringen har Nordenskiöldbreens massbalans en negativ trend, nederbörd har ingen trend och temperatur har en positiv trend. Det är temperatur som styr den långsiktiga massbalansen och den kortsiktiga mellanårs-massbalansen styrs av nederbörds fluktuationer.
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au, taiga@westnet com, and John Rich. "Integrated Mass, Solute, Isotopic and Thermal Balances of a Coastal Wetland." Murdoch University, 2004. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20040520.130717.
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Mass, solute (chloride), isotope (deuterium) and thermal balances were completed at Perry Lakes, two semi-permanent 'water table' lakes near Perth, Western Australia. All balance components except groundwater discharge/recharge were measured independently. These difficult to measure groundwater components of lake-aquifer interaction were estimated by integrating mass, solute and chloride data in sequential 4 day balances spanning two years. Before urbanisation, such wetlands functioned predominantly as flow-through lakes. Now, large winter storm water inputs (and summer artificial level maintenance pumped locally from groundwater) dominate. In East Lake these inputs together comprise 42% of the annual water budget; groundwater discharge is reduced to just 2%. Even under flow-through conditions, these 'non natural' inputs are so large East Lake always tends towards a recharge state and commonly becomes a local groundwater mound. Flow-through is established in both lakes over winter. Initially each lake functions separately however as winter progresses shared capture and release zones are established. Maintenance of lake levels in early summer forces East Lake back to recharge status.
Sediment heat flux (Qse) is significant in these very shallow lakes. Over summer Qse was negative, with a net movement of heat from the water into the sediments which act as a seasonal heat sink. In winter Qse was positive and stored summer heat was returned to the water column. This flux at times exceeded 40 W m-2. Evaporation was determined independently by floating pan, leaving Qse as the thermal balance residual. Ignoring Qse, annual evaporation determined by thermal balance was over estimated by 7%. Over and under estimates of individual 12 day balance period evaporation exceeded 50%.
Monthly Class A (Perth airport) pan coefficients varied from 0.54 (January) to 0.86 (September). Ten empirical equations for evaporation were calibrated and compared with the East Lake floating pan. Best performer was the Makkink which tracked the floating pan closely throughout all seasons. Poorest were the Penman, DeBruin-Keijman, Priestly-Taylor and Brutsaert-Stricker which grossly over estimated late winter evaporation. Transpiration from Typha orientalis, estimated using hydrograph techniques was 43% of open water evaporation in summer and 28% annually. Temperature controlled evaporation pans (tracking lake temperature) experimentally determined the local deuterium content of lake evaporate ÔE, required for isotopic balances. Techniques employing pans evaporated to dryness and pans evaporated at constant volume were run in tandem continuously for two years.
This study singularly integrates mass, solute and isotope balances thereby allowing groundwater components to be accurately quantified. The isotope balances are unique, being the only such balances incorporating experimentally derived local deuterium values of lake evaporate. This study represents the only thermal balance, the only accurate determination of pan-lake coefficients and the first calibration of commonly used empirical evaporation equations for Swan Coastal Plain wetlands.
Groundwater levels in the western suburbs of Perth have declined over 40 years and a disproportionate larger decline now seriously threatens Perry Lakes. Modelling suggests regional groundwater extraction exceeds recharge. Wetland managers can no longer maintain East Lake via local groundwater extraction. Artificial recharge using imported surface and waste water are possible future management options.
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Galarraga, Maider. "Heat balance of a historical church- transmission losses." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-17137.
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The structure of old monumental churches differs a lot from contemporary buildings. The structural materials were wood, brick and stone. In order to construct high buildings with huge spans, thick massive walls and many massive columns were needed. Originally these buildings had no heating and for centuries the outdoor temperature determined the indoor climate. As churches are considered historical heritage buildings their renovation should be thoroughly studied. In this thesis the transmission losses of Hamrånge church will be analysed. Hence, the transmission trough walls and windows as well as the heat buffering of materials will be examined. In addition, the effect of possible reformation measurements will be concluded. Finally, this project belongs to a complete study of the church, were not only transmission losses are considered but also air infiltration losses and solar heat gain. That way, a comparison between them will be carried out in order to contribute to attain the objective of the project: possible restoration for church heating system with respect to preservation, energy requirements, thermal comfort and aesthetics.Church project
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Rainville, Simon 1974. "A two-ion balance for high precision mass spectrometry." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/16934.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2003.Includes bibliographical references (leaves 121-124).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
This thesis describes the demonstration of a new technique that allows masses to be compared with fractional uncertainty at or below 1 x 10-11, an order of magnitude improvement over our previous results. By confining two different ions in a Penning trap we can now simultaneously measure the ratio of their two cyclotron frequencies, making our mass comparisons insensitive to many sources of fluctuations (e.g. of the magnetic field). To minimize the systematic error associated with the Coulomb interaction between the two ions, we keep them about 1 mm apart from each other, on a common magnetron orbit. We have developed novel techniques to measure and control all three normal modes of motion of each ion, including the two strongly coupled magnetron modes. With the help of a new computer control system we have characterized the electric field anharmonicities and magnetic field inhomogeneities to an unprecedented level of precision. This allows us to optimize the trap so that our measurement of the cyclotron frequency ratio is to first order insensitive to the field imperfections. Using the ions 13C2H2+ and 14N2+, we performed many tests of our understanding of the ions dynamics and of the various sources of errors in this technique. From these we conclude that there should be no systematic error in our measurements at the level of 5 x 10-12. Thus we feel confident reporting a value for the mass ratio of these ions with an uncertainty of 10-11.
(cont.) In this thesis, we also report measurements of the two mass ratios m[33S+]/m[32SH+] and m[29Si+]/m[28SiH+] with a relative uncertainty of less than 10-1l, which makes them the best known mass ratios to date. These can be combined with precise measurements of high-energy gamma-rays to provide a direct test of the relation E = mc2. This is a test of special relativity which does not rely on the assumption of a preferred reference frame. The uncertainty on the atomic mass of 29Si is also reduced by about an order of magnitude.
by Simon Rainville.
Ph.D.
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da, Silva Cerozi Brunno, and Silva Cerozi Brunno da. "Phosphorus Dynamics, Mass Balance and Mineralization in Aquaponics Systems." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/620832.
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This study involves tracing inputs, partitioning, and outputs of phosphorus (P) through an aquaponics system. A mathematical model was developed to describe the dynamics of phosphorus in an aquaponics nutrient solution, and to maximize P use efficiency and minimize P waste. We assessed the influence of pH on the availability and speciation of phosphorus in an aquaponics nutrient solution. By using Visual MINTEQ, a freeware chemical equilibrium model for the calculation of element speciation, solubility equilibria, and sorption for natural waters, it was discovered that high pH values favor the formation of calcium phosphate complexes, decreasing the concentration of free phosphorus in aquaponics nutrient solutions. In addition, the mineralization of organic phosphorus in aquaponics systems was evaluated using treatments with phytase supplementation to fish diets, and incorporation of a microbial inoculant in the aquaponics nutrient solution. Overall, dietary phytase and microorganisms promoted phosphorus mineralization and enhanced phosphorus utilization in aquaponics systems. In the end, we conclude that aquaponics systems can keep the same growth performance and quality of vegetable crops grown in conventional systems when the availability and dynamics of phosphorus are well managed.
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Filipovic, Marko. "Mass balance of perfluoroalkyl acids in the Baltic Sea." Licentiate thesis, Stockholms universitet, Institutionen för tillämpad miljövetenskap (ITM), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-88779.
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Perfluoroalkyl acids (PFAAs) are man-made chemicals. Their unique properties make them beneficial for a wide range of industrial and consumer applications, such as constituents in fire fighting foams, hydraulic oils and food packaging materials.PFAAs have shown to be highly persistent in the environment, and the toxicological potential of long chain PFAA homologues is of a concern. International regulation and voluntary actions by the industry have been implemented and led to reduced primary emissions of PFAAs to the environment. However, the concentrations of some PFAAs in e.g. birds from the Baltic Sea are still very high and of ecotoxicological concern. Measures to reduce the PFAA contamination require an understanding of the sources and how the PFAAs are being transported in the environment.In this licentiate thesis a mass balance was assembled for perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDA) and perfluorooctane sulfonic acid (PFOS) in the Baltic Sea. A one-box model was used including the input pathways river inflow, atmospheric deposition, wastewater discharges and inflow from the North Sea via the Danish Straits, while the loss processes considered were sediment burial, transformation of the chemicals and outflow to the North Sea via the Danish Straits. Additionally, the inventories of the four target PFAAs in the Baltic Sea were estimated. Both chemical fluxes and inventories were estimated using recently published monitoring data (2005-2010).In order to obtain a detailed perspective on the current knowledge regarding PFAAs in the Baltic Sea, challenges and uncertainties in data selection were discussed for the most dominant input pathways. This included WWTP emissions and calculation of emission factors (EFs), atmospheric deposition and riverine inflow.River inflow and atmospheric deposition were the dominant inputs, while wastewater treatment plant (WWTP) effluents made a minor contribution. The input to the Baltic Sea exceeded the output for all 4 PFAAs, suggesting that inputs were higher during 2005-2010 than during the previous 20 years despite efforts to reduce emissions of PFAAs. Comparing the difference between PFAA input and output with the PFAA inventory, the doubling time for the concentration in the Baltic Sea was estimated to be 8-94 yr for PFHxA, 12-16 yr for PFOA, 3-5 yr for PFDA and 4 yr for PFOS. The surplus of the input can be an effect of retention and delayed release of PFAAs from atmospheric deposition in the soils and groundwater of the watershed.The licentiate thesis contributes to a holistic understanding of the major input and output pathways and inventories of PFAAs in the Baltic Sea. Furthermore, it points out current knowledge gaps in our understanding of sources and fate of PFAAs in the aquatic environment.At the time of the defence the following papers were unpublished and had a status as follows: Paper 1: Manuscript
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Akhand, Victoria. "Mass Balance Model of Impurities for the WoodRoll Process." Thesis, KTH, Skolan för kemivetenskap (CHE), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-215931.
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The depletion time for fossil fuels calculated from 2009 is 35 years for oil, 37 years for gas and 107 years for coal. Hence, it has become essential to reduce the dependence on fossil fuels by switching over to renewable resources. This in turn will also help in combating the negative effects on the environment like global warming. Thermochemical processes such as pyrolysis and gasification of biomass are considered the most efficient technology for converting biomass to useful energy carriers. Cortus Energy AB is a Swedish company that has developed a patented gasification technology called WoodRoll ® for gasification of fuels derived from biomass. However, ash in a thermochemical conversion process can cause corrosion, sintering, slag and poisoning of catalysts, which leads to operational problems. In addition, heavy metals such as Zn, Pb and Cd are environmentally problematic. These metals contribute to environmental pollution by contaminating the soil, which in turn can harm humans and the ecosystem via the food chain. The undesired elements should therefore be identified to minimize their impact on the overall thermochemical process and to reduce the emission of these harmful substances. The objective of this master thesis project, on behalf of Cortus Energy AB, was to investigate possible key numbers that can be used to describe and predict how the ash behaves in their patented WoodRoll® process. The key numbers that have been identified are empirically developed based on experience of coal combustion. These key numbers are regularly used for fuel derived from biomass by companies specializing in analyzing, although knowledge about whether they can actually be used on biomass is limited. In order to ensure that the use of these for biomass is correct, they must be experimentally verified in the future. In addition, a theoretical investigation is conducted to study which species can form and in what phase this occurs. The investigation reveals that there are no clear trends for how the inorganic elements behave since contradicting results from different studies have been reported. Formation of species and their phase depends on several parameters such as temperature, heating rate, particle size, volatility, quantity and interaction between the elements in the biomass. The thesis project ends with a mass balance model on selected inorganic elements for wood residues, as well as for bark. The model could be a tool for Cortus Energy AB to identify approximately how much of each element is present in each stream in the WoodRoll® process. The models are verified with analysis results. Inorganic elements that affect the overall process and its equipment have been selected for modelling. The volume percent of H2, CO, CO2 and CH4 in the models agree well with the values obtained by Cortus Energy AB. This shows that the thermodynamic equilibrium calculations performed are reasonable.De fossila bränslena beräknas vara förbrukade om 35 år för olja, 37 år för gas och 107 år för kol, räknat från år 2009. Användningen av fossila bränslen måste därför minskas genom övergång till förnybara resurser. Detta kommer i sin tur bidra till att motverka de fossila bränslenas negativa effekter på miljön, såsom den globala uppvärmningen. Termokemiska processer, som pyrolys och förgasning av biomassa, anses vara den mest effektiva tekniken för att omvandla biomassa till användbara energibärare. Cortus Energy AB är ett svenskt företag som har utvecklat en patenterad förgasningsteknik kallad WoodRoll ® för förgasning av biomassa. Aska i en termokemisk omvandlingsprocess kan ge upphov till korrosion, sintring, slagg samt förgiftning av katalysatorer vilket leder till operativa problem. Dessutom är tungmetaller såsom Zn, Pb och Cd miljömässigt relevanta. Dessa metaller bidrar till förorening av miljön, vilket i sin tur kan skada människor och ekosystemet via näringskedjan. De oönskade elementen bör därför identifieras för att minimera deras inverkan på den övergripande termokemiska processen och för att reducera utsläppet av dessa ämnen. Syftet med detta examensarbete, på uppdrag av Cortus Energy AB, var att undersöka möjliga nyckeltal som kan användas för att beskriva och förutse hur askan beter sig i deras patenterade WoodRoll® process. De nyckeltal som har undersökts teoretiskt är empiriskt utvecklade utifrån erfarenhet av förbränning av kol. Dessa nyckeltal används regelbundet av analysföretag på bränslen från biomassa trots att kunskapen om huruvida dessa faktiskt kan användas på biomassa är begränsad. För att säkerställa att användningen av dessa nyckeltal för aska från biomassa är korrekt måste de verifieras experimentellt i framtiden. Vidare görs en teoretisk undersökning för att studera vilka föreningar som möjligen kan bildas och i vilken fas detta sker. Denna undersökning visar att det inte finns en tydlig trend för hur de oorganiska elementen beter sig då olika studier har rapporterat motstridiga resultat. Vilka föreningar som bildas och i vilken fas i processen det i så fall sker beror på flera parametrar såsom temperatur, hastighet av uppvärmning, partikelstorlek, volatilitet, mängd samt interaktionen mellan de element som finns i biomassan. Arbetet avslutas med en massbalansmodell på utvalda oorganiska element för grenar och toppar, förkortat GROT, samt för bark. Detta kan bli ett verktyg för Cortus Energy AB för att identifiera ungefär hur mycket av varje element som finns i varje flöde WoodRoll®-processen. Modellen verifieras med analysresultat. Oorganiska element som påverkar processen och dess utrustning har valts för denna modell. Volymprocenten för H2, CO, CO2 and CH4 i modellen stämmer väl överens med de värden som Cortus Energy AB har erhållit. Detta visar att de termodynamiska jämviktsberäkningar är rimliga.
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Nadim, Pedram. "Irreversibility of combustion, heat and mass transfer." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-13651.
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Combustion is by far the most commonly used technology for energy conversion. The analysis of entropy generation and exergy loss is normally used to optimize thermal energy technologies such as gas turbines. The loss of exergy in the combustor is the largest of all component losses in gas turbine systems. The exergy efficiency of gas turbine combustors is typically 20-30%. In recent years the focus on reduction of climate gas and pollutant emissions from combustion has been a driving factor for research on combustion efficiency. The emphasis on fuel economy and pollution reduction from combustion motivates a study of the exergy efficiency of a combustion process. A bulk exergy analysis of the combustor does not take into account the complexity of the combustion process. The spatial dimensions of the flame must be accounted for in order gain detailed information about the entropy generation. This motivates a study of the local entropy production in a flame and quantifying the mechanisms that reduce the exergetic efficiency. The entropy production in combustion is also believed to have an effect on the stability of the flame. As most combustors operate with turbulent flow the emphasis of this report is on turbulent combustion.The source of exergy destruction or irreversibility in combustion is generally attributed to four different mechanisms: chemical reaction, internal heat transfer, mass diffusion of species, and viscous dissipation. The irreversibilities from the first three sources have been computed for a turbulent hydrogen H2 jet diffusion flame using prescribed probability density functions and data from experiments. The contribution of each source of exergy destruction is locally quantifed in the flame. Two different modeling assumptions are made, one based on a fast chemistry assumption and the other based on curve fitted relations from experimental data. The second law efficiency of the flame was found to be 98.7% when assuming fast chemistry, and 76.0% when curve fits from experimental data where used.The contribution from viscous dissipation has in previous studies been found to be negligible, and in order to simplify the modeling of the turbulent flow its contribution to the total entropy production has not been studied in this report.
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Keyhani, Alireza. "Heat and mass transfer in layered seedbed." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq23997.pdf.
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Wee, H. K. "Heat and mass transfer in confined spaces." Thesis, University of Canterbury. Chemical and Process Engineering, 1986. http://hdl.handle.net/10092/5879.
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A novel experimental technique had been used to investigate the simultaneous transfer of heat and moisture in a simulated building cavity by natural convection. This technique employed two porous plastic plates as the two cavity walls and this arrangement allowed the imposition of a simultaneous moisture gradient on top of a temperature gradient and vice-versa. Both aiding and opposing-flow conditions were investigated for the vertical and horizontal cavity configuration. The aspect-ratio of the experimental cavity used was 7.0 and the fluid investigated was air.
The experimental results were correlated in the form of Nusselt and/or Sherwood number versus an appropriately defined Rayleigh number which depended on the type of gradient causing the flow. The Nusselt and Sherwood numbers were found to agree well with the theoretical values of this work obtained from numerical calculation using a finite-difference technique. The temperature, concentration, stream-function and velocity fields from the numerical calculation also augmented the experimental results.
As no previous results on the rate of moisture-transfer and s interaction with the rate of heat-transfer in an actual building cavity were available, the results of this work addresses this gap in the literature. Under the conditions investigated, which corresponded to the actual temperature and moisture gradients in a typical building cavity in New Zealand, the simultaneous temperature gradient had increased significantly the rate of moisture transfer while the presence of the simultaneous moisture gradient had not increased significantly the rate of heat transfer.
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Zhang, Guodong. "Heat and mass transfer in porous media." Thesis, University of Leeds, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392321.
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Reichrath, Sven. "Convective heat and mass transfer in glasshouses." Thesis, University of Exeter, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391213.
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Arístegui, Jesús Jaime. "Heat balance of a historical church : Air infiltration losses." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-17150.
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James, Kelley J. "Impact of Heat Exposure on Postural Balance of Firefighters." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1397235487.
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Gannon, Maureen Aine. "The energy balance of pigs outdoors." Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308769.
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Arendt, Anthony Alan. "Approaches to modelling the mass balance of High Arctic glaciers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq22565.pdf.
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Spikes, Vandy Blue. "A Mass Balance Study of the West Antarctic Ice Sheet." Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/SpikesVB2003.pdf.
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Vernon, Christopher L. "Surface mass balance model intercomparison for the Greenland ice sheet." Thesis, University of Bristol, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.633454.
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our simulations of the surface mass balance (SMB) of the Greenland ice sheet (GrIS) are compared over the period 1960-2008. Three use a regional climate model to downscale ECMWF reanalysis (ERA-40) and operational analysis data, while the fourth uses the same inputs but an empirical downscaling approach and melt model. These reconstructions have been used in a variety of applications but prior to this study little was known about their consistency with each other and the impact of the downscaling method on the result. The reconstructions are compared to assess the consistency in regional, seasonal and integrated 5MB components and evaluated against a suite of observational data. Three key areas of difference between the models have been identified. Firstly differences in how the ERA-40 reanalysis data are downscaled by the models. Secondly differences in how the 5MB components are calculated. And thirdly differences in the domain, the ice sheet mask used. Total 5MB estimates for the GrIS are in agreement within 34% of the four-model average when a common ice sheet mask is used. When models' native land/ice/sea masks are used this spread increases to 57%. The components of 5MB, with the exception of refreeze, show a similar level of agreement once a common mask is used. Previously noted differences in the models I estimates are partially explained by ice sheet mask differences. Agreement is higher (18% spread) in the accumulation area than the ablation area (38% spread) suggesting relatively high uncertainty in the estimation of ablation processes. Regionally there is less agreement, suggesting spatially compensating errors improve the integrated estimates. Modelled 5MB estimates are compared with in situ observations, gravimetric observations from GRACE and altimetry observations from ICESat. Through the use of a surface density and firn compaction model individual components of 5MB are, indirectly, able to be evaluated against altimetry observation.
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Ranasinghe, Milinda A. "Modelling the mass and energy balance in a compost biofilter." Thesis, University of Canterbury. Chemical and Process Engineering, 2003. http://hdl.handle.net/10092/7492.
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A biofilter model was developed using the mass and energy balances in the gas, liquid and solid phases, which related the biofilter performance to the water content in the packing material. A key simplification of the model was that the concentration gradients in the biofilm were neglected by treating the biofilm/water layer as well mixed and in instantaneous equilibrium with the gas phase. Thus, the biofilm geometry and density parameters were lumped into the overall degradation term. The solid phase was treated as a separate well-mixed layer but solid phase dynamics were accounted for by using the Linear Driving Force (LDF) mass transfer model. The mixed form of Richard's equation together with experimentally obtained unsaturated hydraulic conductivity and water retention curves for compost were used in the continuity equation for the liquid water phase. This approach produced a model where all parameters could be potentially independently determined.
The model was used to test suitable irrigation strategies for a biofilter system degrading toluene subject to different operational conditions. Under this approach both unidirectional and directionally switched biofilter configurations were tested for a 1 m long column. The unidirectional schemes incorporated both open and closed loop irrigation schemes, where the latter was based on commonly used on-line moisture measurement techniques. All schemes were evaluated based on the removal efficiency achieved and the leachate produced. Simulations under a constant irrigation rate of 5.46x 10⁻²g/m²s for a mass loading range of 13-60 g/m³h yielded removals ranging from 88%-26%. An order of magnitude drop in leachate under the high loading indicated severe drying in the system. For a high mass loading of 60 g/m³h, directional switching with a one-day frequency yielded a removal of 33% Vs 26% in an up flow scheme with similar leachate rates. Feedback control on water content provided an improved removal of 84% as compared to 73% under constant irrigation, when both schemes were subjected to load and inlet air step disturbances from 13 g/m³h to 62 g/m³h and from 298 K to 283 K respectively. A sensitivity analysis indicated that the model was most sensitive to the relationship between moisture content and degradation, which was also reflected by the high sensitivity of the model to the kinetic parameters in the degradation term.
A novel batch recycle reactor was thus developed to investigate the effect of water content changes on the degradation rate in low water content systems such as biofilters. The reactor tightly controlled the water content of the unsaturated packing material by using the principle of a suction cell. Experimental runs were performed with toluene as the contaminant using unamended compost at a constant temperature of 30°C. Matric potential in the compost was maintained at values between -6 and -36 cm H₂O and the gas phase was monitored by sampling/gas chromatography. A soil water retention curve relating matric potential to gravimetric water content was generated for the compost. Periodic dry weight analyses of reactor samples together with the water retention curve verified moisture content control. Degradation results demonstrated a biologically limited region followed by a non-linear region at lower concentrations. Elimination capacities were obtained along the wetting and drying curves and changes in the water content affected the removal rates in the linear region ranging from 155 g/m³h to 24 g/m³h over the matric potential range investigated. Repeatability studies indicated that moisture content was the most likely parameter that influenced the changes in performance. Batch scale experiments were also performed using microbially inhibited compost, which provided linear sorption isotherms for toluene on compost at concentrations between 0-1000 ppmv and temperature values of 25°C and 35°C.
The simulation model developed here provides a useful tool to implement and evaluate various operational schemes under different irrigation strategies. This is achieved by way of greater flexibility in incorporating the various schemes into the base model and the comparatively low simulation time to obtain the relevant results.
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Meister, R. "Estimating Antarctic ice sheet mass balance from gravimetry and altimetry." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1364858/.
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Estimates of the Antarctic ice sheet mass balance from the past ten years show great discrepancy. Deriving mass values from gravity measurements is a ffected by corrections for postglacial rebound (PGR). Calculating Antarctic ice sheet mass balance from altimetry satellites requires knowledge of surface densities. Here, two instruments were used in conjunction to constrain ice sheet mass balance. Surface height trends from the Envisat radar altimeter and mass trends from GRACE were analysed for the period January 2003 until October 2010. An analysis of errors related to GRACE gravity measurements was carried out and a best method for removal of errors was chosen. Envisat altimetry corrections were examined. Envisat surface height trends were converted into units of mass and smoothed with a 300km Gaussian filter in order to be compatible with the GRACE mass trend. This was done using a) the density of ice (917kg=m3), b) a firn density of 450kg=m3 and c) a variable surface density map of the Antarctic derived from observations of changes in the pattern of surface height trends. Subtracting the altimetry mass trend from the GRACE mass trend provides results dominated by the absence of altimetry data in the Antarctic peninsula and south of 81:6 degrees south. Therefore, ICESat altimetry trend values were added to the Envisat trend map, where available. The GRACE mass trend and the smoothed altimetry trend converted to mass show very good agreement. The diff erence between GRACE and the combined Envisat-ICESat altimetry trends can be interpreted as a combination of PGR and error. Integrating this di fference provides considerably smaller PGR values than all commonly used PGR models. The integrated area trends from both gravimetry and altimetry show mass loss for West Antarctica, mass gain for East Antarctica and an acceleration of melting in the Amundsen Sea Sector.
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Kunzen, Thomas. "HYDROLOGIC MASS BALANCE OF PERVIOUS CONCRETE PAVEMENT WITH SANDY SOILS." Master's thesis, University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3249.
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Use of pervious concrete pavement as a method of stormwater management has shown great promise in previous studies. Reduction in runoff, water quality improvements, and long-term economic benefits are but a few of its many advantages. Regulatory agencies such as the St. Johns River Water Management District require further research into the performance of pervious concrete pavement before granting credits for its use as a best management practice in controlling stormwater. As a part of a larger series of studies by UCF's Stormwater Management Academy, this thesis studies the hydrologic mass balance of pervious concrete pavement in sandy soil common in Florida. In order to conduct this study, a field experiment was constructed at the UCF Stormwater Field Lab. The experiment consisted of three 4-foot tall cylindrical polyethylene tanks with 30-inch diameters. All three tanks were placed into the side of a small embankment and fitted with outlet piping and piezometers. The test tanks were assembled by laying a 6-inch layer of gravel into the bottom of each tank, followed by a layer of Mirafi geofabric, followed by several feet of fine sand into which soil moisture probes were laid at varying depths. Two of the tanks were surfaced with 6-inch layers of portland cement pervious concrete, while the third tank was left with a bare sand surface. Mass balance was calculated by measuring moisture influx and storage in the soil mass. Data collection was divided into three phases. The first phase ran from August to November 2005. Moisture input consisted of normal outdoor rainfall that was measured by a nearby rain gauge, and storage was calculated by dividing the soil mass into zones governed by soil moisture probes. The second phase ran for two weeks in March 2006. Moisture input consisted of water manually poured onto the top of each tank in controlled volumes, and storage was calculated by using probe readings to create regression trendlines for soil moisture profiles. The third phase followed the procedure identical to the second phase and was conducted in the middle of April 2006. Data tabulation in this study faced several challenges, such as nonfunctional periods of time or complete malfunction of essential measuring equipment, flaws in the method of calculating storage in phase one of the experiment, and want of more data points to construct regression trendlines for soil moisture calculation in phases two and three of the experiment. However, the data in all phases of the experiment show that evaporation volume of the tanks with pervious concrete surfacing was nearly twice that of the tank with no concrete. Subsequent infiltration experiments showed that pervious concrete pavement is capable of retaining a portion of precipitation volume, reducing infiltration into the underlying soil and increasing total evaporation in the system.M.S.C.E.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Civil Engineering
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Wong, T.-Y. "Mass balance of heavy metal pollution in a river catchment." Thesis, University of Manchester, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382893.
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VERA, YSRAEL MARRERO. "PREDICTING MERCURY CONCENTRATION IN TUCUNARÉ USING MASS BALANCE AND BIOENERGETICS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=6133@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORO mercúrio usado no garimpo do ouro na região amazônica é liberado para a atmosfera, solo e rios. Uma vez na atmosfera, o metal é oxidado e imediatamente se deposita. Na água, ocorre a transformação para o metilmercúrio principalmente pela ação de microrganismos. A formação do metilmercúrio aumenta a dispersão e biodisponibilidade do elemento no ambiente aquático. O metilmercúrio pode ser incorporado pelo plancton entrando, assim, na cadeia alimentar. A concentração do metal aumenta a medida que se ascende nos níveis tróficos da cadeia, atingindo os valores mais elevados em peixes carnívoros como o tucunaré. Dessa forma, as emissões de mercúrio provocam a contaminação dos recursos naturais e aumentam os riscos para a saúde dos consumidores habituais de pescado. O objetivo deste trabalho é testar um modelo de bioacumulação de mercúrio em peixes para estimar concentrações em predadores de topo da cadeia alimentar. O modelo pode ser usado como ferramenta para a gestão ambiental de ecossistemas aquáticos potencialmente contaminados com mercúrio. Este objetivo foi atingido através da combinação dos modelos de balanço de massa de Trudel e bioenergético de Wisconsin, aplicados em espécies tropicais do gênero Cichla (tucunaré) da bacia do rio Tapajós. O modelo bioenergético de Wisconsin foi usado para determinar as taxas de consumo de alimento a partir de dados de crescimento estimados. Os parâmetros usados nos modelos foram obtidos na literatura. A habilidade da modelagem na predição dos teores de mercúrio em tucunarés foi avaliada através da comparação com dados de campo obtidos nos anos 1992 e 2001, no rio Tapajós e no sistema de lagos Maicá. Os melhores resultados foram alcançados para os espécimes coletados no ano 1992, o que parece estar relacionado com uma melhor estimativa da concentração de mercúrio no alimento neste ano.
The mercury used in the artisanal mining (garimpo) of gold in the Amazon region is emitted to the atmosphere, soil and rivers. Once in the atmosphere, the metal is oxidized and immediately deposited. In the water, the transformation to methylmercury takes place mostly due to the action of microorganisms. The formation of methylmercury increases the dispersion and bioavailability of the element in the aquatic environment. The methylmercury can be assimilated by the plankton and enters the food chain. The concentration of the metal increases further up in the trophic levels of the chain and reaches the highest values in carnivorous fishes like tucunaré. Thus, the mercury emissions cause the contamination of natural resources and enhance the risks to the health of regular fish consumers. The objective of this work is to test a model for bioaccumulation of mercury in fishes. The model calculates concentrations in top predators of the food chain and can be used as a tool for the management of aquatic ecosystems potentially contaminated with mercury. This objective was accomplished through the combination of the Trudel mass balance and Wisconsin bioenergetics models, applied to tropical species of the Cichla (tucunaré) genre of the Tapajós river basin. The Wisconsin bioenergetics model was utilized to determine the rates of food consumption from estimated fish growth data. The parameters used in the models were found in the literature. The ability of the models to predict mercury contents in tucunarés was evaluated by comparison with the field data, obtained in 1992 and 2001, in the Tapajós River and in the Maicá lakes. The best results were attain ed for specimens collected in 1992 what seems to be related to a better estimate of mercury concentration in the food in this year.
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BARRETO, GISELE DE OLIVEIRA. "MASS BALANCE DATA RECONCILIATION OF THE URUCU- MANAUS GAS PIPELINE." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2015. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=26316@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
Se por um lado à privatização do setor de energia, que induz acirrada concorrência, tem estimulado a inovação tecnológica e a adoção de mecanismos de incentivos à eficiência operacional, a regulação do mercado introduz mecanismos de controle requerendo maior responsabilidade no uso consciente da energia de sorte a assegurar a eficiência energética e a proteção ambiental. Pressões de organizações ambientalistas internacionais e a crescente demanda por energia explicam a tendência mundial pelo uso de combustíveis fósseis mais limpos. O baixo nível de emissões e resíduos associados ao processo de combustão de gás natural qualifica esta commodity energética como um elemento estratégico para integrar a matriz energética de organizações e países comprometidos com a sustentabilidade global. O impacto econômico associado à medição de gás natural exige uma otimização do controle do balanço de massa no sistema de entrega. A aplicação da Metodologia de Reconciliação de Dados constitui o objetivo deste trabalho. A técnica provou ser uma ferramenta eficaz para a avaliação do balanço de massa em um gasoduto durante o período de operação associado ao transporte de gás natural. A natureza intrínseca do seu algoritmo de cálculo, que leva em conta a redundância nas medições, qualifica a metodologia para aumentar a confiabilidade da medição assim reduzindo a incerteza individual associada a cada grandeza física capaz de interferir na medição e identificar erros grosseiros. Fundamentado na avaliação metrológica do balanço de massa de um gasoduto brasileiro, os resultados do estudo permitem discutir a adequação da técnica proposta de reconciliação de dados. Dentre as conclusões do trabalho, foi possível mostrar que o uso da técnica de tratamento dos dados do gás não contado (unaccounted for gas) pode atingir valores inferiores a 0,3 porcento, comparando-se, assim, à tolerância preconizada em nível internacional.
If on the one hand, privatization of the energy sector, which induces keen competition, has stimulated technological innovation and the adoption of incentive mechanisms for operational efficiency, regulation of the market introduces control mechanisms requiring greater responsibility in the conscious use of energy so as to ensure energy efficiency and environmental protection. Pressure from international environmental organizations and the growing demand for energy, explain the worldwide tendency for the use of cleaner fossil fuels. The lower levels of emissions and residues associated with the combustion process of natural gas classify this energy commodity as a strategic element to enter into the energy matrix of organizations and countries committed to global sustainability. The economic impact associated with the measurement of natural gas, demands optimization in controlling the mass balance in the delivery system. Application of the Data Reconciliation Methodology constitutes the objective of this work. The technique proved to be an efficient tool for the evaluation of the mass balance in a gas pipeline for the period of operation associated with the transport of natural gas. The intrinsic nature of its calculation algorithm, which takes into account the redundancy of measurements, qualifies the methodology to increase the confidence of measurement, thereby reducing the individual uncertainty associated with each physical volume capable of interfering with the measurement and identify gross errors. Based on the metrological evaluation of the mass balance of a Brazilian pipeline, the results of the study enable discussion on the adequacy of the data reconciliation technique proposed. Among the conclusions of the work, it was possible to demonstrate that the use of the technique in treating the data of unaccounted for gas, could achieve values lower than 0.3 percent, thereby comparable with the tolerances advocated at international level.
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Rivera, Andres. "Mass balance investigations at Glaciar Chico, Southern Patagonia Icefield, Chile." Thesis, University of Bristol, 2004. http://hdl.handle.net/1983/987b1d4c-49ea-4dab-b53d-a054a453faa6.
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The Southern Patagonia Icefield (SPI) is the largest temperate ice mass at mid-latitudes in the Southern Hemisphere, and an area where most glaciers have been retreating during the last 50 years. Based on field data, vertica aerial photographs and satellite images, the changes experienced by Glaciar Chico, are presented. These glacier variations are compared to climatic changes recorded in Patagonia during recent decades through modelling of the glacier mass balance, using a degree-day factor model forced with climatic and field data. The main aim of this work is to analyse the mass balance of Glaciar Chico, in order to distinguish climatically driven glacier behaviour from tha which could be related to ice dynamics. Between the end of the Little Ice Age and the middle of the 20`h century the glacier retreated at relatively low rates, but in recent decades there has been an acceleration in the rate of ice thinning and area loss of up to 0.33 ± 0.22 km2 a"1. In total, the volume lost due to frontal retreat and area change between 1975 and 2001 is -1.73 ± 1.43 km3 water equivalent (w. eq. ). Although the glacier was slowly thinning before 1975, during recent decades the rate of thinning has accelerated to reach a maximum of -5.4 ± 0.55 m a-1 at the glacier front. From GPS data, ice thinning was also observed at the lower elevations of the accumulation area, at an average rate of -1.9 ± 0.14 m a"' between 1998 and 2001. Interestingly, the thinning rate in the lower accumulation zone is three times higher than the mass balance estimated for that part of the glacier. Analysis of climatic data showed a warming trend of up to +0.033°C a-' between 1969 and 1990, and a trend of decreasing precipitation of up to -27 mm a"2 between 1961 and 1990. The mass balance model was run several times in order to obtain the best-fit parameters which were calibrated with direct observations of accumulation and ablation from glaciers across Patagonia. The resulting net mass balance for Glaciar Chico obtained from the model yielded an average of -0.165 ± 0.059 km3 a-' w. eq. between 1975 and 2001, but this only accounts for three quarters of the volume lost by the glacier due to ice elevation changes (-0.226 ± 0.081 km3 a"1 w. eq. ). It is therefore concluded that in addition to the response of Glaciar Chico to climatic changes, a dynamic component also affects its behaviour, which could possibly be related to enhanced sliding generated by an increase in melt water, and/or a long term change in the glacier and its neighbours in the SPI.
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Taylor, Astrea. "Phosphorus mass balance for hypertrophic Grand Lake St. Marys, Ohio." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1347933945.
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Okumura, Yutaka. "Mass Balance and Bioaccumulation of Major Dioxins in Sendai Bay." Kyoto University, 2011. http://hdl.handle.net/2433/135409.
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Fang, Yuan-Hao, Xingnan Zhang, Chiara Corbari, Marco Mancini, Guo-Yue Niu, and Wenzhi Zeng. "Improving the Xin'anjiang hydrological model based on mass–energy balance." COPERNICUS GESELLSCHAFT MBH, 2017. http://hdl.handle.net/10150/625180.
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Conceptual hydrological models are preferable for real-time flood forecasting, among which the Xin'anjiang (XAJ) model has been widely applied in humid and semi-humid regions of China. Although the relatively simple mass balance scheme ensures a good performance of runoff simulation during flood events, the model still has some defects. Previous studies have confirmed the importance of evapotranspiration (ET) and soil moisture content (SMC) in runoff simulation. In order to add more constraints to the original XAJ model, an energy balance scheme suitable for the XAJ model was developed and coupled with the original mass balance scheme of the XAJ model. The detailed parameterizations of the improved model, XAJ-EB, are presented in the first part of this paper. XAJ-EB employs various meteorological forcing and remote sensing data as input, simulating ET and runoff yield using a more physically based mass–energy balance scheme. In particular, the energy balance is solved by determining the representative equilibrium temperature (RET), which is comparable to land surface temperature (LST). The XAJ-EB was evaluated in the Lushui catchment situated in the middle reach of the Yangtze River basin for the period between 2004 and 2007. Validation using ground-measured runoff data proves that the XAJ-EB is capable of reproducing runoff comparable to the original XAJ model. Additionally, RET simulated by XAJ-EB agreed well with moderate resolution imaging spectroradiometer (MODIS)-retrieved LST, which further confirms that the model is able to simulate the mass–energy balance since LST reflects the interactions among various processes. The validation results prove that the XAJ-EB model has superior performance compared with the XAJ model and also extends its applicability.
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Guastella, L. A.-M. "The sea surface heat balance in the Benguela upwelling region." Master's thesis, University of Cape Town, 1987. http://hdl.handle.net/11427/22447.
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Bibliography: pages 191-202.The surface heat balance of the Benguela upwelling area on the west coast of southern Africa is analysed. Measurements of the components of the heat balance were made in the St Helena Bay area from 14-21 October 1986. Additional long-term data was obtained from Alexander Bay and Cape Town. An average net heat gain of 227 W.m⁻² was received over the eight days of the field study. The presence of cold water determined that latent heat loss by the sea surface was small, while the sensible heat flux represented a small gain by the sea. These two turbulent heat fluxes are roughly equal and opposite and therefore approximately cancel each other. Use of a model, assuming idealised conditions, indicated that most turbulent heat exchange between the air and takes place in the nearshore region where air-sea contrasts are greatest. The net radiation was found to provide a good estimate of the total heat balance, thus the major contributing term to a high heat balance over the Benguela area is the input solar radiation. Minimal synoptic variation in the heat balance during the eight-day field programme was observed, but additional global radiation data analysed revealed that synoptic variations over the 3-6 day period are in fact more significant than the longer term seasonal variations. Both synoptic and seasonal variations in the heat balance are greater in the south than in the north. The high heat flux into the sea surface is capable of increasing the temperature of the upwelled water at a fairly rapid rate. During summer the heat exchange is capable of increasing the temperature of the upper 10 m mixed layer by as much as 0.65°C over one day. This input heat is used to realise the high biological potential of the upwelled waters.
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Knapke, Robert. "High-Order Unsteady Heat Transfer with the Harmonic Balance Method." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1427962937.
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Kilic, Ilker. "Heat And Mass Transfer Problem And Some Applications." Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614140/index.pdf.
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Numerical solutions of mathematical modelizations of heat and mass transfer in cubical and cylindrical reactors of solar adsorption refrigeration systems are studied. For the resolution
of the equations describing the coupling between heat and mass transfer, Bubnov-Galerkin method is used. An exact solution for time dependent heat transfer in cylindrical multilayered annulus is presented. Separation of variables method has been used to investigate the temperature behavior. An analytical double series relation is proposed as a solution for the temperature distribution, and Fourier coefficients in each layer are obtained by solving some
set of equations related to thermal boundary conditions at inside and outside of the cylinder.
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Lindblom, Jenny. "Condensation irrigation : simulations of heat and mass transfer." Licentiate thesis, Luleå : Luleå University of technology, 2006. http://epubl.luth.se/1402-1757/2006/08.
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