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1999 Uppsatser om Ground water modeling - Sida 36 av 134
Nitrogen flow in Scania : substance flow analysis on a regional level
In this thesis, the flows of reactive nitrogen (Nr) in Scania were investigated and quantified. The thesis was also intended to form a basis for comparison between the urban nitrogen flow and other flows of nitrogen within Scania. The management of nitrogen in society has disturbed the natural nitrogen cycle. This is linked to a series of environmental problems such as eutrophication, acidification, global warming and smog.
The method used was Substance Flow Analysis (SFA) for Nr. For calculation and flow charts Scania was divided into three subsystems; air, water and society.
Fosforprocesser i Bornsjön, Stockholms reservvattentäkt - dynamisk massbalansmodellering med LakeMab
Bornsjön är Stockholms viktigaste reservvattentäkt och kan tillgodose staden med dricksvatten i flera månader om Mälaren skulle slås ut. Det är därför viktigt att Bornsjön håller en god vattenkvalitet. Under de senaste åren har vattenkvaliteten avseende totalfosfor i Bornsjön försämrats. Hög belastning av fosfor kan leda till övergödning i en sjö. När en sjö är övergödd uppstår ökad syreförbrukning som kan leda till syrebrist.
Marktäckande, lågväxt vegetation på ställverksmark : en biologisk bekämpningsmetod mot ogräs
Unwanted vegetation on the land of electric transforming stations is a problem, in the sense that it contributes to higher fire risks and also constitutes an obstacle for people performing maintenance operations at the station. Such unwanted vegetation is controlled using herbicides and mechanical measures. Since the use of herbicides implies environmental hazards, there is a need to find alternative ways of fighting the unwanted vegetation.
Investigation into suitable plants for ground cover, trials in the greenhouse, trials in the field, soil analyses and compilation of experiences from similar trials are parts of this work. The paper also contains analyses of possible environmental benefits and economical gains. There is also a final discussion of some proposals regarding alternative weed controlling methods.
Uthållig sanitet : en förstudie i staden Picota, Peru
The access to good sanitary facilities is an important factor that elevates the experienced living standard as it improves hygiene and reduces the transmission of deseases. The ratification of the millennium goals by 189 countries demonstrates that this is an important international issue. Together the countries have taken upon themselves that the proportion of the population that lacked access to sustainable safe drinking water and sanitary facilities in the year 2000 will have been reduced by half by the year 2015.
In Peru, the construction of sewage pipe networks to transport the sewage out of the direct human environment is progressing. The safety and sustainability of these systems can be questioned, since in Peru the sewage seldom receive any treatment before being emitted to a recipient. This is taking place in Picota and sorrunding villages as well.
In the last 25 years several systems implementing small-scale onsite treatment have been introduced throughout Latin America in an attempt to give more people access to sustainable and safe sanitary facilities, reducing water consumption and taking advantage of the agricultural values of the sewage fractions while protecting the environment from its negative impact.
In this study three different sanitary systems and the effects of different population growths were compared.
Analys och förbättring av en mätenhet för laddning av elfordon
Reducing the CO2-pollution, resulting from the combustion of fossil coal for energyproduction, is important to affect environmental changes. One way to achieve a reductionis to use the oxy-fuel technology. The technology uses O2 and re-circulated flue gasduring the combustion which results in a flue gas mainly consisting of CO2. The flue gascould then be compressed and stored without environmental effects. A problem thatfollows from the compression is the risk of acidification in sensitive parts of the process.Acidification can occur because of reactions following from the contact of condensedwater and sulphur- and nitrogen-oxides which are also present in the flue gas.This report compiles and evaluates the basis of a scientific unit with the purpose ofexploring the possibilities of extracting impurities of SOx and NOx from the flue gases.The dimensions of the unit are based on basic conditions, defined for an existing oxy-fuelprocess at Chalmers, and on the results of computer modelling.
Termomekanisk utmattning av Sanicro 25 : Materialmodellering med finita elementmetoden
The report aims to describe the austenitic stainless steel Sanicro 25 from a thermomechanical point of view. The thermal and mechanical properties of the material make it suitable for use in coal ? and thermal power plants. By the use of Sanicro 25 it would be possible to bring the efficiency of these plants up while bringing the carbon emissions down.A material model is created from material testing and validated through simulation in the finite element software Abaqus. The model that has been derived describes the material behavior during loading and stress relaxation for the first cycle in a thermomechanical fatigue test well.
SYNS VI I SVERIGE? : En rättssäkerhetsstudie om barn i migrationsprocessen
The current thesis is on the rule of law and how the principles of the rule of law are met in thenew Swedish migration process. The migration process has been subjected to criticism duringseveral years and on different occasions. The migrations process is viewed through a ?rightsof the child? perspective, foremost to seek if the rights of the child are met. The children are avulnerable group, not the least in the process of migration.
Analys och gestaltning av miljön kring vattentornet i Uppsalas stadsskog
The water tower in Uppsala city forest was built in the late 1950's in what is now a nature reserve. The unique place was supposed to be visited by people, which is currently not the situation. This bachelor thesis aimed to perform an analysis and make a design proposal for the environment surrounding the water tower. The analysis was performed using the methodology previously described by architect Arne Branzell. The methodology focuses on how a space is perceived by a person moving through it.
Sjöars känslighet för klimatförändringar ? vilka faktorer påverkar?
The Earths climate is changing at a higher rate, i.e between 1861 and 1994 the annual mean temperature in Scandinavia increased with 0,68º C and according to recent climate models the annual mean temperature is likely to rise with another 3º C during this century.A warmer climate in many ways is associated with changing conditions for lake ecosystems. An expected higher water temperature and a stronger summer stratification of the water column increases the risk of anoxic conditions at the lake bottom. Thus anoxic conditions are likely to cause a phosphate leakage from the sediment, i.e. a higher internal loading of phosphate.In this project, the extremely warm summer of 2002 has been used as an example for a possible scenario for a future climate. By comparing levels of phosphorus in the summer of 2002 with a ten-year median value, a phosphorus related sensitivity to climate change has been analyzed for 55 Swedish lakes.
Föroreningstransport i grundvatten : En modelljämförelse
This thesis compares different methods for risk assessment of a creosote contaminated site in Vansbro, Dalarna. In a complementary study the importance of using representative data for calibration and validation of stationary groundwater models is discussed. The time dependency between surface water levels and groundwater levels on the site in Vansbro is evaluated by step response analysis. The results show that the groundwater levels reflect only long-term variation in the surface water levels. Hence the use of such long-term means for calibration and validation of the stationary groundwater models is the only theoretically defendable alternative.As a first step in the comparison of risk assessment methods the degree of contamination is evaluated on the basis of generic guideline values for contaminated soils, developed by the Swedish Environmental Protection Agency.
Tillagning i mikrovågsugn och dess effekt på livsmedel : En jämförelse med konventionell tillagning
Microwave is a time- efficient device for heating and reheating of foods. Despite the fact that its effects on foods have been evaluated during a long period of time, without any more negative effects shown compared to conventional cooking, one third of the Swedish population believes (in 2010) it accounts for a higher loss of nutrition.
This literature review aim to compile studies regarding how food is affected by cooking in microwave, with respect to cooking losses, nutrition, secondary metabolites as well as sensory and textural aspects and compare it with conventional cooking.
The compilation shows that different combination of effect (W), time and amount of water during microwave cooking have different effects on foods. The contents of proteins, vitamin B and carbohydrates are generally higher after microwave cooking, while anti-nutritional substances are affected much less during conventional cooking. This also depends on if it is of animal or non-animal origin. However, for the majority of nutrition values the differences are quite small.
Är plöjningsfri jordbearbetning bättre än konventionell plöjning? :
The background of this study is the fact that it nowadays is more common to grow wheat after wheat. Usually we plow every autumn to remove the straw, and we wanted to study the effect of alternative methods to do it. We have done this experiment to answer the question if no tillage is better than conventional plowing. The results of the field experiment indicate that there is a link between plant establishment and the choice of equipment, but also a higher weed pressure in experimental plots with only ground tillage. The equipments which left much straw on the top of the ground the problems with fungi were more severe.
Vindpark Vänern : Fundamentteknik och Logistik
An analysis of a specific application of anaerobic wastewater treatment at a pulp and board mill, Stora Enso Skoghall, was carried out. A literature study was done and effluent wastewater from CTMP pulp production was analyzed. The analysis consisted of a broad constituent analysis and an anaerobic treatment trial. Results from these test where used to calculate the treatment effectiveness and resulting energy potential at the mill.The literature study and constituent analysis showed that toxicity of the water to be treated, due to wood extractives and sulphur content, was of concern. Detoxification chemicals targeting these constituents where used in the anaerobic treatment trial.
Tillagning i mikrova?gsugn och dess effekt pa? livsmedel : en ja?mfo?relse med konventionell tillagning
Microwave is a time- efficient device for heating and reheating of foods. Despite the fact that its effects on foods have been evaluated during a long period of time, without any more negative effects shown compared to conventional cooking, one third of the Swedish
population believes (in 2010) it accounts for a higher loss of nutrition.
This literature review aim to compile studies regarding how food is affected by cooking in microwave, with respect to cooking losses, nutrition, secondary metabolites as well as sensory and textural aspects and compare it with conventional cooking.
The compilation shows that different combination of effect (W), time and amount of water during microwave cooking have different effects on foods. The contents of proteins, vitamin B and carbohydrates are generally higher after microwave cooking, while anti-nutritional substances are affected much less during conventional cooking. This also depends on if it is of animal or non-animal origin.
However, for the majority of nutrition values the differences are quite small.
NEDKYLNING HOS VANLIG B?NA, PHASEOLUS VULGARIS
Beans are a global source of plant-based protein, and in some countries, they constitute a primary source of protein intake. With ongoing climate change, including rising temperatures, it is necessary to adapt beans to ensure a reliable food supply. An important mechanism that many plants have, to cope with high temperatures, is cooling through transpiration. During transpiration, stomata open and release water vapor. Water molecules use heat energy from the leaf to convert into gas, thereby cooling the leaf.