Pureza é um dos principais atributos de qualidade de matérias-primas farmacêuticas, já que a identificação e determinação quantitativa de impurezas podem ajudar a controlar/minimizar o risco de efeitos adversos de medicamentos. O papel dos métodos de doseamento, tanto específicos como não específicos, em caracterizar a qualidade de matérias-primas farmacêuticas, tem sido questionado. Por outro lado, a abordagem do balanço de massas, que quantifica cada impureza orgânica bem como substâncias voláteis e cinzas, e então subtrai a soma destas impurezas de 100%, pode oferecer uma melhor maneira de determinar com exatidão se o fármaco atende aos critérios regulatórios de aceitação e de detectar com confiança mudanças não esperadas na qualidade do fármaco. O objetivo do estudo foi comparar métodos de doseamento compendiais com essa abordagem de balanço de massas na determinação do conteúdo de substância ativa e caracterização da qualidade de matérias-primas farmacêuticas. Os fármacos empregados neste estudo foram o nifedipino, o diazepam, a glibenclamida e a estavudina. A identificação e caracterização dos fármacos foram realizadas por meio de determinação do ponto de fusão e espectroscopia no infravermelho. Para a determinação quantitativa foram empregados os métodos presentes na Farmacopéia Brasileira, United States Pharmacopeia e British Pharmacopeia. O detector de aerossol carregado (CAD) foi acoplado ao sistema de cromatografia à líquido de alta eficiência para comparação das respostas com o detector ultravioleta. Os resultados demonstraram a viabilidade do método indireto, que oferece dados mais precisos que os do método direto, além de favorecer um controle de qualidade mais focado no perfil de impurezas. / Purity is one of the main attributes of quality of bulk drug materials, since the identification and quantitative determination of impurities can help to avoid or at least control/minimize the risk of their contribution to the side effects profile of drug materials. The role of assay methods, either specific or non-specific, in characterizing the quality of bulk drug materials, has been questioned. On the other hand, the mass balance approach, which quantifies every organic impurity as well as volatile substances and ashes, and then subtracts the sum of these impurities from 100%, can provide a better way to accurately determine if the drug substance meets the regulatory acceptance criteria and to reliably detect unexpected changes in the quality of the drug substance. The objective of this study was to compare compendial assay methods with a mass balance approach in the determination of the active ingredient content and characterization of the quality of bulk drug materials. The identification and characterization of the drugs were accomplished through determination of melting point and infrared spectroscopy. The methods from the Farmacopeia Brasileira, United States Pharmacopeia and British Pharmacopoeia were used for the quantitative determination of the drugs. The drug related impurities were determined by high performance liquid chromatography (HPLC) equipped with an ultraviolet (UV) detector and charged aerossol detector (CAD) in tandem. The results demonstrated the feasibility of the indirect method, which offers more precise data than those from the direct method, besides it enables the quality control to be focused on the impurity profile.

A dissertação versa sobre a lateritização do depósito Madeira que ocorre associado à fácies albita granito do granito Madeira (tipo A, ~ 1,82 Ga). O depósito Madeira situa-se na floresta amazônica, onde intemperismo químico é intenso e lateritização é um importante processo de formação de depósitos minerais. Este depósito representa um caso particular, onde a rocha-mãe é um depósito mineral; assim, mineralização primária e mineralização laterítica ocorrem no mesmo perfil. A rocha-mãe tem uma associação mineral incomum, que inclui quartzo, albita, k-feldspato, zircão, criolita (Na3AlF6), fluorita, polilitionite, riebeckita rica em Zn, F-anita rica em Zn, torita, cassiterita, pirocloro, columbita, xenotima, gagarinita- (Y), fluocerita-(Ce) e genthelvite. Uma característica importante da rocha é a sua riqueza em flúor (2 a 6% em peso), principalmente sob a forma de criolita ou fluroita na matriz. Inicialmente foram investigadas as alterações micromorfológicas destes minerais ao longo de perfis de intemperismo. Em seguida, os realizados estudos geoquímicos em perfis selecionados. Os dados químicos foram convertidos em proporções volumétricas para quantificar as variações nos teores de elementos em amostras com diferentes graus de lateritização, e foram realizados cálculos de balanço de massa tendo o Al como elemento de referência. Desta forma, foram obtidas muitas informações sobre os processos que atuaram na formação do perfil laterítico a partir do depósito Madeira. A rocha-mãe representava claramente um sistema aluminoso com quantidades mais baixas de Fe. A perda total de álcalis e perda parcial de SiO2 originou argilas cauliníticas. A razão molar de SiO2/Al2O3~2 foi adequada para a geração de minerais de argila aluminosos com estrutura 1:1, tais como a caulinita. Com a maior perda de SiO2 na parte superior do perfil ocorreu a formação de gibsita. Hematita é principal mineral de ferro formado porque o meio foi alcalino com alta razão OH/Fe (>2). A lixiviação de elementos alcalinos conduziu ao enriquecimento relativo de alguns elementos economicamente importantes, tais como Sn, Nb e ETR. No entanto, a distribuição de alguns metais, tais como o Pb, Zn e ETR, difere do padrão normalmente esperado no intemperismo, o que pode ser explicado por algumas características especiais da paragênese e pela alta atividade de F nas soluções, que influenciou os processos intempéricos de duas maneiras diferentes: intensa corrosão até mesmo de minerais muito resistentes e formação de complexos estáveis, especialmente com cátions duros, tais como os ETR. / The paper deals on the laterization of the Madeira deposit associated with the albite-enriched granite facies of the A-type Madeira granite (~1.82 Ga). The Madeira deposit is located in the Amazon rain forest, where chemical weathering is intensive and lateritization is a major process of ore deposit formation. This deposit represents a particular case, where the parent rock is an ore deposit; thus primary mineralization and lateritic mineralization occur in the same profile. The parent rock has an unusual mineral association, which includes quartz, albite, k-feldspar, zircon, cryolite (Na3AlF6), fluorite, polylithionite, Zn-rich riebeckite, Zn-F-rich annite, thorite, cassiterite, pyrochlore, columbite, xenotime, gagarinite-(Y), fluocerite-(Ce), and genthelvite. An important feature of the rock is the F richness (2 to 6% wt) mainly in the form of cryolite or fluorspar in the matrix. We first investigated the micromorphological changes of these minerals throughout the soil profile and then focused the geochemical studies in selected profiles. The chemical data were converted into volumetric proportions to quantify the variations in element contents in samples with different degrees of lateritization, and we performed mass balance calculations with Al as the reference element. In this way, we obtain many new constraints on the processes that formed the weathering profile from the Madeira deposit. The parental rock was a clearly aluminous system with lower amounts of Fe. The total loss of alkalis and partial loss of SiO2 created kaolinitic clay minerals. The SiO2/Al2O3 molar ratio ≈2 was suitable for generating aluminous clay minerals with 1:1 structures, such as kaolinite. Greater losses of SiO2 occurred and gibbsite formed at the top of the weathering profiles. Hematite formed as the main ferric mineral because the medium was alkaline with a high OH-/Fe ratio (> 2). The leaching of alkaline elements led to relative enrichment in some economically important elements, such as Sn, Nb, and REEs, in the lateritic profiles. However, the distribution of some of the metals, such as Pb, Zn, and REEs, in the weathering profile is very unusual and may be explained by some special characteristics of the paragenesis and the high activity of F in the solutions, which greatly influenced the weathering processes in two different ways. This halogen was responsible for the intense corrosion of even very resistent minerals and formed stable complexes, especially with hard cations such as REEs.

A produção brasileira de frangos de corte evidenciou-se com o sistema de produção integrada, ao elevar a eficiência e a qualidade na conversão de proteína animal. Contudo, devido à rápida evolução tecnológica com crescente demanda energética e a diversificação dos sistemas de produção em diferentes microclimas, elucidar os processos de conversão de massa e energia tornou-se uma tarefa desafiadora neste sistema de produção. Constantemente, pesquisadores, produtores e agroindústria buscam processos mais rentáveis, reduzindo a demanda em mão de obra e o impacto ambiental. No entanto, nunca foi feita uma avaliação integrada do sistema produtivo de frangos de corte, considerando-se os aspectos quantitativos, energéticos e ambientais. Deste modo, o objetivo deste trabalho é promover um detalhado balanço de massa e energia, além de avaliar por meio da análise exergética, a qualidade das conversões de energia no processo produtivo de frangos de corte. Com o levantamento de insumos, produtos e rejeitos diretos, vinculados ao ciclo de produção, foram quantificadas as vazões mássicas para os diferentes processos do ciclo e, aplicando-se a avaliação exergética, obteve-se um diagnóstico completo da quantidade e qualidade energética envolvidas. Considerando o cenário adotado, em termos mássicos, as maiores demandas identificadas para os insumos foram a água (69,2%) e a ração (24,9%). Na saída do processo, os Gases de Efeito Estufa (GEE)/particulados extraídos através da ventilação (39,4%), os gases de combustão da lenha (25,6%) e a cama (14,2%) formam os principais rejeitos. A massa de frangos representa 20% das saídas. Foi identificado que a relação entre o consumo de água e ração é função da temperatura. Em termos energéticos, as maiores contribuições identificadas para os insumos foram a ração (77,7%) acompanhada do material absorvente (9,7%) e da lenha (9,6%). Na saída do processo lideram as energias associadas aos frangos (33,2%) e da cama gerada (32,1%). O rendimento energético obtido para galpões convencionais foi de 27%. Os processos que mais destroem exergia dentro do ciclo produtivo são a formação da cama de frangos a partir das excretas (51,5% em convencionais e 48,2% em climatizados) e a combustão da lenha para aquecimento (21,9% em convencionais e 20,5% em climatizados). Além disso, foi estimado o rendimento de Segunda Lei para o ciclo próximo de 26%. Foram introduzidos os índices energético e exergético de produção permitindo a comparação entre diferentes sistemas. Como principal resíduo, a cama de frangos gerada no ciclo, quando reutilizada como insumo para aquecimento do próprio aviário na forma de briquetes, pode elevar as eficiências. Comparando-se as demandas médias para as duas formas de aquecimento, foi constatado que o uso do GLP é mais favorável ao ambiente se comparado à lenha, devido à forma direta de transferência de calor aos frangos. É aconselhável, em dias quentes, elevar a velocidade do ar, utilizando o resfriamento evaporativo somente em casos de elevada temperatura ambiente, pois a introdução de água eleva a exergia dissipada no ciclo. / Brazilian production of broilers has been highlighted with the implantation of the integrated production system, which improved the efficiency and quality in animal protein conversion. However, due to the rapid technological evolution with the increasing energy demand and the diversification of production systems in different microclimates, elucidating mass and energy conversion processes has become a challenging task regarding this production system. Constantly, researchers, producers and agribusiness look for more profitable processes, reducing the labour demand and environmental impact. However, an integrated evaluation of the productive system of broilers, considering the quantitative, energy and environmental aspects has never been carried out. Thus, this study aims at promoting a detailed mass and energy balance and to evaluate the quality of the energy conversions in the productive process of broilers by means of exergy analysis. With the survey of inputs, products and direct wastes, linked to the production cycle, the mass flow rates for the different processes of the cycle were quantified and a complete diagnosis of the quantity and quality energetic involved was obtained applying the exergy evaluation. Considering the scenario adopted, in mass terms, the greatest demands identified for the inputs were water (69.2%) and feed (24.9%). At the exit of the process, the greenhouse gases/dust extracted through ventilation (39.4%), the firewood combustion gases (25.6%) and the litter poultry generated (14.2%) are the main outputs. The broilers mass was quantified in 20%. The relation between water and feed consumption has shown to be the temperature. Regarding energy, the largest contribution identified for the inputs was feed (77.7%) followed by the absorbent (9.7%) and firewood (9.6%). At the exit of the process lead the energy associated with the broilers (33.2%) and the poultry litter generated (32.1%). The energy performance obtained for conventional shed was 27%. The processes of the largest exergy destroyed within the productive cycle are the litter poultry converted from excreta (51.5% in conventional and 48.2% in air conditioning) and the combustion of wood for heating (21.9% in conventional and 20.5% in air conditioning). In addition, the second law performance for the cycle was estimated in about 26%. The energy and exergy production index was introduced allowing for the comparison among different systems. As the main residue, the litter poultry generated in the cycle when reused as an input for heating the aviary itself in the form of briquettes, can increase these efficiencies. The use of LPG is more environmentally friendly compared to wood, considering the average demands for the too forms of heating, due to the direct form of heat transfer to the broilers. It is advisable, on hot days, to raise the air speed using the evaporative cooling only in cases of high ambient temperature, as the introduction of water raises the exergy dissipated in the cycle.

Neste trabalho, foram levantados dados sobre o tratamento da água e os resíduos gerados nos decantadores e filtros da ETA Fonte Luminosa, localizada em Araraquara, que é do tipo convencional com decantadores de alta taxa, objetivando-se obter parâmetros sobre a qualidade e quantidade dos resíduos gerados na ETA referida. Foram analisados e relacionados fatores relevantes na geração e composição destes resíduos, tais como: consumo de produtos químicos, procedimentos operacionais e qualidade da água bruta. O trabalho foi dividido em três etapas. Na primeira, foi realizada a caracterização física e operacional da ETA Fonte Luminosa através de visitas e levantamento de dados históricos da água afluente à estação, da água tratada, dos produtos químicos e dos dados operacionais da estação no período de 2001 a 2003. Na segunda etapa, realizou-se a caracterização qualitativa da água nas diversas etapas do tratamento em termos de pH, cor aparente, turbidez e sólidos; nos resíduos originados nos decantadores e filtros, também, foi realizada a caracterização qualitativa (DQO, nitrogênio total, fosfato total, pH, cor aparente, turbidez e sólidos) e quantitativa (medida e estimada com o emprego de balanço de massas) dos. A ultima etapa, foi a avaliação da ocorrência de metais (Fe, Cd, Zn, Ni, Cu, Pb, Cr e Mg) na água ao longo do tratamento e nos resíduos. Os processos e as operações empregadas no tratamento influenciaram diretamente na qualidade e na quantidade dos resíduos. No período observado, os resultados indicaram grande semelhança entre os resíduos gerados nos decantadores de alta taxa e filtros da ETA Fonte Luminosa. Notou-se grande divergência entre os resíduos gerados em decantadores convencionais (ETA São Carlos) e de alta taxa (descargas diárias). Observou-se a ocorrência de chumbo, níquel e cromo total na água tratada em valores acima do Padrão de Potabilidade fixado pela Portaria nº 518/MS de 25/03/2004. / In this work, it was made a data survey about the water treatment and the residuals generated in the settling tanks and filters from the Fonte Luminosa WTA located at Araraquara-SP, a conventional type WTA with high rate settling tanks; aiming to obtain parameters about the quality and quantity of residuals generated at this WTA. The relevant parameters in the residuals generation and composition, like the chemical consume, the operational proceedings and the raw water quality, were evaluated and related to each other. The work was divided in three stages. In the first, it was made the physic and operational characterization from the Fonte Luminosa WTA by means of visits and historical data surveys from the water that enters the WTA, the treated water, the chemicals used and the operational data from the period of 2001 to 2003. In the second stage, it was made a qualitative characterization from the water in several stages of the treatment, with the parameters: pH, apparent color, turbidity and solids; to the residuals generated in the settling tanks and filters, it was also made the qualitative characterization with the parameters: COD, total nitrogen, total phosphate, pH, apparent color, turbidity and solids; and it was made a quantitative characterization for these residuals (measured and estimated by the mass balance). The last stage was the evaluation of the occurrence of metals (Fe, Cd, Zn, Ni, Cu, Pb, Cr and Mg) in the total water treatment and in the residuals. The processes and operations applied in the water treatment have a direct influence in the quality and quantity of the generated wastes. In the observed period, the results show a great similarity between the wastes generated in the high rate settling tanks and filters from this WTA. It was observed a great difference between the residuals generated in conventional settling tanks (São Carlos WTA) and high rate settling tanks (daily discharge). It was observed the occurrence of lead, nickel and chrome in the treated water, with values bigger than the ones fixed by the Portaria nº 518/MS from 03/25/2004 to a drinking water.

Masters of Science / Over the years, South Africa has produced over 468 million tons of mine waste yearly, in which gold mining waste accounted for 221 million tons (47%) of all mine waste produced, making it the largest, single source of waste and pollution. The exposure of these mine wastes such as tailings dams, waste rocks to oxidation and leaching has been the source of heavy metal release into the environment. This study assessed the magnitude of possibly leachable metals, its distribution and associations and predicted the AMD load discharge over time, from Mogale’s tailings dam into the environs in Randfontein area, Witwatersrand Basin, South Africa. Fifty-one tailings dam samples were analysed for their mineral and multi-elements contents. Petrography studies was done by X-Ray Diffraction (XRD) technique to determine the mineralogical composition. X-ray fluorescence (XRF) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) techniques were used to determine the multi-elements content in the tailings dam samples. The dataset were evaluated using multivariate statistics, Geographical Information Systems (GIS) and geochemical mass balance techniques. From the results, the tailings dam lithology was grouped into four distinct layers. The uppermost oxidized layer is siliceous and contains the highest SiO2 (87.32%) contents, which is with the lowest contents in Tot/S, U, As, Zn, Ni, Co, and Cu. A downward decrease in SiO2 (76.39%) contents occurs, coupled by an increase in Fe2O3, Tot/S, U, As, Zn, Ni, Co, and Cu, reaching maximum contents in layer 3. Layer 4 is the least weathered horizon. The cluster analysis grouped the samples into four sub-clusters based on the variation in SiO2 and Al2O3 contents. Factor analysis (83.542% total data variance) related the four controlling factors of element distribution to the occurrence in ore elements (sulphides), silicates, mining additives and refractory minerals. Elements of the same origin show a similar concentration trend down hole in the GIS interpolation analysis. The geochemical mass balance showed variable gain and loss of oxides and trace elements within each layer. Based on the variation patterns of the Tot/S contents and other mobile elements, about 0.164kg/tonne/yr(±0.02) of the tailings materials are leached yearly. Layer 1 is the most altered. This assessment and prediction study therefore gives an insight to the geochemical behaviour of an abandoned tailings dam, highlighting its extent of oxidation. However, the interaction between the oxidized zone and transition zone should be given more attention, to determine the actual extent of damage.

<p>Our understanding of the climate of northern Sweden during the late Holocene is largely dependent on proxy-data series. These datasets remain spatially and temporally sparse and instrumental series are rare prior to the mid 19th century. Nevertheless, the glaciology and paleo-glaciology of the region has a strong potential significance for the exploration of climate change scenarios, past and future. The aim of this thesis is to investigate the 19th and 20th century climate in the northern Swedish mountain range. This provides a good opportunity to analyse the natural variability of the climate before the onset of the industrial epoch. Developing a temporal understanding of fluctuations in glacier front positions and glacier mass balance that is linked to a better understanding of their interaction and relative significance to climate is fundamental in the assessment of past climate.</p><p>I have chosen to investigate previously unexplored temperature data from northern Sweden from between 1802 and 1860 and combined it with a temperature series from a synoptic station in Haparanda, which began operation in 1859, in order to create a reliable long temperature series for the period 1802 to 2002. I have also investigated two different glaciers, Pårteglaciären and Salajekna, which are located in different climatic environments. These glaciers have, from a Swedish perspective, long observational records. Furthermore, I have investigated a recurring jökulhlaup at the glacier Sälkaglaciären in order to analyse glacier-climate relationships with respect to the jökulhlaups. </p><p>A number of datasets are presented, including: glacier frontal changes, in situ and photogrammetric mass balance data, in situ and satellite radar interferometry measurements of surface velocity, radar measurements, ice volume data and a temperature series. All these datasets are analysed in order to investigate the response of the glaciers to climatic stimuli, to attribute specific behaviour to particular climates and to analyse the 19th and 20th century glacier/climate relationships in northern Sweden.</p><p>The 19th century was characterized by cold conditions in northern Sweden, particularly in winter. Significant changes in the amplitude of the annual temperature cycle are evident. Through the 19th century there is a marked decreasing trend in the amplitude of the data, suggesting a change towards a prevalence of maritime (westerly) air masses, something which has characterised the 20th century. The investigations on Salajekna support the conclusion that the major part of the 19th century was cold and dry. The 19th century advance of Salajekna was probably caused by colder climate in the late 18th and early 19th centuries, coupled with a weakening of the westerly airflow. The investigations on Pårteglaciären show that the glacier has a response time of ~200 years. It also suggests that there was a relatively high frequency of easterly winds providing the glacier with winter precipitation during the 19th century.</p><p>Glaciers have very different response times and are sensitive to different climatic parameters. Glaciers in rather continental areas of the Subarctic and Arctic can have very long response times because of mass balance considerations and not primarily the glacier dynamics. This is of vital importance for analyzing Arctic and Subarctic glacier behaviour in a global change perspective. It is far from evident that the behaviour of the glacier fronts today reflects the present climate.</p>

<p>This work is about finding an appropriate modelling complexity for a mass-balance model for phosphorus in Lake Vänern, Sweden. A statistical analysis of 30 years of water quality data shows that epilimnion and hypolimnion have different water quality and should be treated separately in a model. Further vertical division is not motivated. Horizontally, the lake should be divided into the two main basins Värmlandssjön and Dalbosjön. Shallow near shore ares, bays and areas close to point sources have to be considered as specific sub-basins if they are to be modelled correctly.</p><p>These results leads to the use of a model based on ordinary differential equations. The model applied is named LEEDS (Lake Eutrophication Effect Dose Sensitivity) and considers phosphorus and suspended particles. Several modifications were made for the application of the model to Lake Vänern. The two major ones are a revision of the equations governing the outflow of phosphorus and suspended particle through the outflow river, and the inclusion of chemical oxygen demand (COD) into the model, in order to model emissions from pulp and paper mills. The model has also been modified to handle several sub-basins.</p><p>The LEEDS model has been compared to three other eutrophication models applied to Lake Vänern. Two were simple models developed as parts of catchment area models and the third was a lake model with higher resolution than the LEEDS model. The models showed a good fit to calibration and validation data, and were compared in two nutrient emission scenarios and a scenario with increased temperature, corresponding to the green house effect.</p>

In order to improve our knowledge on the current state and variability of the Greenland ice sheet surface mass balance (SMB), a 27-year simulation (1979-2005) has been performed with the coupled atmosphere-snow regional model MAR. This simulation reveals an increase in the main factors of the SMB which are, on the one hand, the snowfall (+ 1.6 ± 1.8 km3 yr-1) in winter and on the other hand, the run-off (+ 4.2 ± 1.9 km3 yr-1) in summer. The net effect of these two competing factors leads to a SMB loss rate of – 2.7 ± 3.0 km3 yr-1, which has a significance of 87%. The melt extent derived from the passive microwave satellite data since 1979 also shows this trend. The melt water supply has increased because the Greenland ice sheet has been warming up by + 0.09 ± 0.04 °C yr-1 since 1979. This warming comes from a uniform increase of downward infra-red radiation which can not be explained by the natural variability. These changes result very likely from the global warming induced by human activities. As a result, it seems that: i) increased melting dominates over increased accumulation in a warming scenario, ii) the Greenland ice sheet has been significantly losing mass since the beginning of the 1980's by an increasing melt water run-off as well as by a probable increase of iceberg discharge into the ocean due to the "Zwally effect" (the melt water-induced ice sheet flow acceleration) and iii) the Greenland ice sheet is projected to continue to lose mass in the future. The Greenland ice sheet melting could have an effect on the stability of the thermohaline circulation (THC) and the global sea level rise. On the one hand, increases in the freshwater flux from the Greenland ice sheet (glacier discharge and run-off) could perturb the THC by reducing the density contrast driving it. On the other hand, the melting of the whole Greenland ice sheet would account for a global mean sea level rise of 7.4 m.

In order to improve our knowledge on the current state and variability of the Greenland ice sheet surface mass balance (SMB), a 27-year simulation (1979-2005) has been performed with the coupled atmosphere-snow regional model MAR. This simulation reveals an increase in the main factors of the SMB which are, on the one hand, the snowfall (+ 1.6 ± 1.8 km3 yr-1) in winter and on the other hand, the run-off (+ 4.2 ± 1.9 km3 yr-1) in summer. The net effect of these two competing factors leads to a SMB loss rate of – 2.7 ± 3.0 km3 yr-1, which has a significance of 87%. The melt extent derived from the passive microwave satellite data since 1979 also shows this trend. The melt water supply has increased because the Greenland ice sheet has been warming up by + 0.09 ± 0.04 °C yr-1 since 1979. This warming comes from a uniform increase of downward infra-red radiation which can not be explained by the natural variability. These changes result very likely from the global warming induced by human activities. As a result, it seems that: i) increased melting dominates over increased accumulation in a warming scenario, ii) the Greenland ice sheet has been significantly losing mass since the beginning of the 1980's by an increasing melt water run-off as well as by a probable increase of iceberg discharge into the ocean due to the "Zwally effect" (the melt water-induced ice sheet flow acceleration) and iii) the Greenland ice sheet is projected to continue to lose mass in the future. The Greenland ice sheet melting could have an effect on the stability of the thermohaline circulation (THC) and the global sea level rise. On the one hand, increases in the freshwater flux from the Greenland ice sheet (glacier discharge and run-off) could perturb the THC by reducing the density contrast driving it. On the other hand, the melting of the whole Greenland ice sheet would account for a global mean sea level rise of 7.4 m.

Traditionally, textiles were dried outdoors with the wind and the sun enhancing the drying process. Tumble dryers offer a fast and convenient way of drying textiles independent of weather conditions. Tumble dryers, however, consume large amounts of electrical energy. Over 4 million tumble dryers are sold each year in Europe and a considerable amount of energy is used for drying of clothes. Increasing energy costs and the awareness about environmental problems related to a large energy use has increased the demand for dryers with better energy efficiency. The aim with this thesis is to show how to improve the energy efficiency of domestic tumble dryers. Two types of tumble dryers are available on the market today: the open cycle dryer and the closed cycle dryer. In the open cycle dryer room air is heated and led into the drying drum. The exhaust air leaves the dryer and is often evacuated outside the building. In the closed cycle dryer an internal airflow is recirculated inside the dryer. When the hot air has passed through the drying drum it is led through a heat exchanger where the water vapour is condensed before the air is heated again and led to the drum. The heat exchanger is cooled with room air. Drying at low temperature has been shown to reduce the specific energy use for an open cycle tumble dryer. In Paper I a correlation between the specific energy use, the drying time and the heat supply was established for a specific load by using the exhaust air temperature. It was shown that the total drying time and specific energy use could be predicted from data during the first hour of the process. This result indicated a possibility to create a control system that makes it possible for the user to choose between low energy use or short drying time. The focus of Paper II is to reduce the energy use for a closed cycle tumble dryer. Energy and mass balances were established in order to determine feasible improvements. Energy and mass flows in the dryer indicated that reducing leakage from the internal system of the dryer gave the largest reduction of specific energy use. Insulation of the back cover of the dryer and opening the internal system during the falling drying rate period also gave positive results on the energy use. In total a feasible reduction of the energy use of approximately 17% was calculated.