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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Nitrat i grundvattnet : Modellanalys av vattenflöde till Hörviks vattentäkt / Nitrate in the groundwater : Model analysis of water flow to Hörvik’s water supply

Petersson, Terje January 2004 (has links)
A well, situated on Listerlandet in the western part of Blekinge in Sweden, has a very high content of nitrate. Water with a too high content of nitrate is hazardous to human health, in particular to small children. The area surrounding the well is mostly drained agricultural land with some larger farms for chicken and mink. The well takes its water from the bedrock and is deeper than most other wells affected by nitrate. The bedrock in the area is dominated by limestone with a relatively high flow of water. This thesis was performed in order to find the source of the nitrate. A groundwater model, simulating the water flow, was created. The model was used to trace the particles flowing to the well in order to find the most likely source. GMS Modflow and Modpath were used to create the model. The validation of the model shows that the model is good enough to be used for further investigation of the groundwater in the area. The model result indicates that the original source for most of the nitrate is some large mink farms situated on the slope of a hill south of the well. Calculation shows that it takes the water 25 years to flow from the farms to the well. There is also a probable contribution of nitrate from the agriculture in the vicinity of the well. But an extensive drainage system brings most of the water from the cultivated area into the Baltic Sea. Conclusions are that a large amount of mink farms placed in a small area contributes to the high content of nitrate in the well. Further examinations are needed to show which measures should be taken in order to diminish the content of nitrate in the well. / En brunn som förser Hörvik med dricksvatten har en hög halt av nitrat. Hörvik ligger på Listerlandet i västra Blekinge. Vatten med för hög nitrathalt är hälsovådligt för människor i allmänhet och spädbarn i synnerhet. Området som omger brunnen består till största delen av dränerad jordbruksmark med några större djurgårdar för broiler och mink. Brunnen är bergborrad och går djupare än de flesta andra nitratpåverkade brunnar i Sverige. Berggrunden i området domineras av kalkberg med ett relativt högt vattenflöde. Ett projektarbete utfördes för att ta reda på ursprungskällan till nitratet. I arbetet skapades en grundvattenmodell som skulle simulera vattenflödena i området och sedan spåra en partikels väg till brunnen för att ta reda på den mest troliga källan. GMS Modflow och Modpath är de dataverktyg som användes. Valideringen av modellen visar att den fungerar tillfredsställande och kan användas för fortsatta undersökningar av grundvattenförhållanden i området. Modellresultat tyder på att ursprungskällan för den största delen av nitratet är några stora minkfarmar som ligger på en sluttning upp mot Listers huvud söder om brunnen; dock har det tagit ca 25 år för vattnet att ta sig från ursprungskällan till brunnen. Jordbruket i närheten av brunnen bidrar sannolikt med en del nitrat, men en omfattande dränering leder den större delen av vattnet från jordbruksområdet ut i Östersjön. Slutsatsen är att ett stort antal minkfarmar i ett begränsat område är en bidragande orsak till brunnens höga nitrathalt. Vidare undersökningar bör visa vilka åtgärder som behövs för att minska nitrathalten i brunnen.
72

Industrial Pollution and Economic Compensation : A  Study of Down Stream Villages in Noyyal River, Tirupur, Tamil Nadu, South India

Santhi Kanna, Dorai Kannan January 2008 (has links)
Tirupur is an Indian textile town which constitutes many dyeing and bleaching units situated in the upstream. Tirupur serves as one of the major exporters of textiles. The industrial pollution have affected not only the surface water but also the soils and ground water. This thesis studies the impacts of industrial pollution on agriculture and livestock. It also explores the implicated problems involved in putting an economic compensation mechanism into practise. The impact study was made on the detailed primary data collected from an intensive study of comparing a pollution affected villages located downstream of the Orathapalyam dam, Tamil Nadu, South India with a control village. The cost estimates that the impact of industrial pollution on predominant crops is quite substantial in monetary terms. This paper argues that the compensation principle might work if the assessment is done to all affected victims. Both quantifying and non quantifying benefits should be incurred in the mechanism. Further, mere passing of fines and creating institutional structures are not sufficient to address the environmental problems. Policies should be implemented in their right perspective. Institutions should be strong enough, with more autonomy and powers, to deal with problems and to monitor the RO plants in dyeing units in Tirupur.
73

Transienta effekter under Lugeon-tester i borrhål / Transient effects during Lugeon-tests in boreholes

Palmfjord, Erik January 2013 (has links)
Hydrogeologiska tester av borrhål har länge varit en viktig metod för att estimera sprickigt bergs hydrogeologiska parametrar såsom transmissivitet och magasinskoefficient. Lugeon-tester är borrhålstester där vatten injekteras i en sektion under konstant tryck som höjs och sänks i steg. Utvärderingen av testet kan ge information om flödet i de vattenledande sprickorna är turbulent eller laminärt samt om det uppstår några geomekaniska effekter, såsom elastisk vidgning av sprickor under testets gång. De ekvationer som rutinmässigt används för utvärdering av testet förutsätter stationärt flöde och tryck i slutet på varje trycksteg, förhållanden som sällan återfinns i verkligheten. Antagandet om stationaritet tros ge en felaktig utvärdering av testet och därför har konsultföretaget Geosigma tagit fram en transient numerisk modell som beskriver Lugeon‑tester och som kan användas för utvärdering av testet. Modellen har i detta examensarbete använts för att utvärdera Lugeon-tester utförda i Rönnskär av Geosigma, men också Lugeon-tester utförda av författaren i Uppsala. Resultatet från utvärderingen har jämförts med utvärderingar med antagande om stationära förhållanden och utvärderingar genomförda med modeller i programvaran AQTESOLV. Dessutom har en känslighetsanalys genomförts för den numeriska modellen. Undersökningar utförda med den numeriska modellen visar att stationära utvärderingar av Lugeon-tester ger en felaktig tolkning av resultatet om stationära förhållanden inte råder. Detta beror på den transienta effekten, där flöde och tryck under ett trycksteg påverkar flöde och tryck under de efterföljande tryckstegen. Utvärderingsmetoden där den numeriska modellen används går ut på att relatera skillnaden mellan modellerat och uppmätt flöde i slutet på varje trycksteg till det rådande differenstrycket i borrhålet. Den nya utvärderingsmetoden ger en säkrare utvärdering av Lugeon-tester eftersom den tar hänsyn till de transienta effekterna. Utvärdering av Lugeon-tester med den nya metoden ger i flera fall andra tolkningar än den stationära utvärderingsmetoden. De båda utvärderingsmetoderna ger samma tolkningar när stationära förhållanden verkligen råder. Utvärderingsmetoden är dock känslig för brusigt data.   ISO-standarden 22282-3 beskriver Lugeon-tester och där rekommenderas att tryckstegen skall vara 10-30 minuter långa. Med den numeriska modellen har dock Lugeon-tester med 2 minuter långa trycksteg kunnat utvärderas på ett tillfredställande sätt. Lugeon‑testernas testtid kan således förkortas betydligt i förhållande ISO-standardens vilket skulle innebära en lägre kostnad för att utföra den här typen av tester. / Hydraulic testing has long been an important method to estimate hydrogeological parameters, such as transmissivity and storativity for fractured rock. Lugeon-tests are single-borehole tests which are performed by injecting water into a borehole section under constant pressure. The pressure is raised and lowered in steps, called pressure steps. The evaluation of the test can give information if the water flow is turbulent or laminar and if the test gives rise to any geomechanical effects, such as an elastic expansion of fractures. The equations that are used for the evaluation of the test assume that the flow and the pressure are stationary at the end of each pressure step. Stationary conditions are however seldom encountered under field conditions. The assumption of staionarity was believed to give rise to incorrect test evaluations. Geosigma has therefore developed a transient numerical model that can describe the transient lapse and can be used for the evaluation of the test. The model has been used to evaluate Lugeon-tests performed by Geosigma in Rönnskär and Lugeon-tests performed by the author in Uppsala. The results have been compared with stationary evaluations and evaluations performed with models in AQTESOLV. Investigations with the numerical model have shown that stationary evaluations of Lugeon-tests give rise to incorrect interpretations when stationary conditions are not present. This depends on the transient effect, where flow and pressure during one pressure step influence the others. The new evaluation method uses the model to relate the difference between modeled and measured flow to the pressure at the end of a pressure step. The new method gives a more correct evaluation of a Lugeon-test since it takes the transient effects into consideration. Evaluations of Lugeon-tests with the new method often give rise to different interpretations of the geomechanical effects and flow conditions compared to the stationary evaluation. The two methods give the same interpretations if the flow is stationary. The new ISO-standard 22282-3 recommends that the pressure steps should last for 10‑30 minutes. Tests with two minute long pressure steps have been evaluated with the new method with satisfying results. This means that the time it takes to perform a test can be shortened considerably and still receive a good result. In the end the method can cut the costs for performing Lugeon-tests.
74

Constructed Wetlands and Buffer Zones as Measures for Agricultural Phosphorus Leakage on a Sub-catchment Scale : The Söderköping River Project

Kokic, Jovana January 2010 (has links)
The Baltic Sea has a major problem with eutrophication where acts have been taken by the EU commission to sign a common action plan, the Baltic Sea Action Plan (BSAP). The overall goal is to reach a good environmental status by the year 2021, where one of the sub-goals is that the Baltic Sea should be unaffected by eutrophication. For Sweden, the goal for phosphorus (P) is to reduce the annual load with 290 tonnes by the year 2021. Since phosphorus is the main limiting nutrient, it is targeted for reduction when it comes to addressing problems with eutrophication. The objective of this thesis is to estimate the effect of constructed wetlands (CW) and buffer zones (BZ), as measures for reducing agricultural phosphorus, in a specific sub-catchment area of the Söderköping river. The waters in this sub-catchment area have the status unsatisfying and poor. If these measures are suitable for this area and where, and if the effect implementation would fulfill a good status for these waters, are questions that this thesis will aim at. An assigned P reduction has been calculated for the sub-catchments where the waters with unsatisfying and poor statuses are present. Areas for CWs have been calculated with the help of the assigned reduction and retentions found in the literature, and location for them has been suggested. With the help of calculated areas for potential BZs for this area, the effect of them have been calculated by retentions found in the literature with 9 and 10 m widths. The results show higher results for assigned P reduction than the actual P load that is present in the sub-catchments. This gives odd results for the effect of the CWs where they show a P reduction of 59-234 %. The method for assigned P reduction is therefore questioned, where the method for the reference value that is used is not without flaws. For BZs, a reduction of 5-14 % is shown, where the reduction is larger with larger areas for potential BZs. Whether the implementation of the measures will fulfill a good status for the waters is difficult to say, due to the inadequate methods and the odd results given in this thesis.
75

Approaches to participative planning : Potential applications in municipal energy planning

Ljung, Stina January 2010 (has links)
This thesis explores potential participatory approaches suitable for a municipal energy planning context. It also analyses the possibility of using those approaches in energy planning processes in ten Swedish municipalities. Swedish municipal energy plans display differences in terms of quality, comprehensiveness and implementation. According to participation literature, planning processes can be improved by stakeholder participation. This study was carried out in four steps: creation of a theoretical framework, survey investigating the municipal energy planners’ views on participation, relating the planners’ views with the theoretical framework and creating suggestions for which participatory approaches to use in the municipalities. Participatory approaches found in literature were categorised into: democracy based, social learning and policy driven participation. Literature states that stakeholder participation should be done as early as possible in a process, but findings from the survey show that those municipalities that have come furthest in their planning process are the ones most interested in stakeholder participation. Indicating that energy planning processes need to gain a sense of maturity before it is even possible to think about involving other stakeholders. Another result shows differences in objectives, central values and targeted stakeholders between the different municipalities. One conclusion from this thesis is the importance for municipalities to understand their objectives for stakeholder participation, since objectives partly determines what kind of participatory approach that will be suitable to use in a given situation.
76

Impacts of Climate Changeson Reservoirs in Northern Sweden : case study of Akkajaure reservoir by modelling

Chang, Yan January 2010 (has links)
Since the middle of the 20th century, the average temperature of the atmosphere near Earthsurface has increased. The global warming causes many effects in hydrological systems, suchas changes in thermal structure, water quality, aquatic ecosystems, etc. This thesis studies theimpact of climate change on Akkajaure reservoir, the second largest regulated reservoir inSweden, by simulating a predicted temperature rise based on the climate and hydrologicalconditions of Akkajaure in 1998-2002. The congeal duration, ice thickness and the turbulentkinetic energy (TKE) in the lake were calculated by the catchment hydrological model and thelake model. The movement of phytoplankton and their mean net production (MeanNP) rateare simulated by the dispersion model and the photosynthesis model. By comparing thesimulation results of past situation and three predicted scenarios, it is obtained that theincreases of temperature shorten the congeal duration, which is a lead factor for shortening thetrough period and amplification of peak value of TKE. The comparison of plankton particlesposition illustrates that the particles stay in a deeper position for a longer time because of thechanges of TKE. Though the plankton stays in euphotic zone longer as the temperatureincreases, the comparison of the mean production rate between the real scenario and thepredicted scenarios concludes that the mean production rate grows as the temperatureincreases because the shortened ice cover period makes the duration of absorbed sunlightincreases in lake. The effects of global warming may influence the distribution of microalgaein on high latitude lakes and reservoirs. The phytoplankton will stay in deeper water layers fora longer time.
77

Reduktion av järn, mangan och CODMn i dricksvatten : Ett pilotförsök vid Högåsens vattenverk / Reduction of iron, manganese and CODMn in potable water : A pilot study atHögåsens water treatment facility

Olausson, Tommy January 2012 (has links)
Högåsens vattenverk som förser Nyköping och Oxelösunds tätorter med vatten använder sig av konstgjord grundvattenbildning. Verket har under en längre tid haft besvär med att producera önskad kvantitet dricksvatten. Kapaciteten begränsas av att ur marken pumpat vatten vid höga uttag innehåller järn- och manganhalter som överstiger lagstadgade gränsvärden. I förhoppning om att öka kapaciteten vid vattenverket borrades 2011 en ny grundvattenbrunn, benämnd V7. Kemiska analyser på vattnet från V7 i samband med provpumpning av brunnen visade dock på förhöjda halter järn, mangan samt COD Mn – kemisk syreförbrukning.För att utreda möjligheterna att använda V7 för dricksvattenproduktion samt komma till rätta med Högåsens mangan- och järnproblem utfördes på vatten från V7 ett pilotförsök, där syresättning och filtrering användes för att reducera halterna av järn och mangan i vattnet. Resultaten visar på att järnhalten reduceras effektivt, medan manganhalten ej förändras genom pilotanläggningen. Den kemiska syreförbrukningen i råvattnet från V7 är hög, vilket ger bilden av ett syrefattigt grundvattenmagasin som under lång tid belastats med syreförbrukande organiskt material. För att kunna använda grundvattenbrunn V7 för dricksvattenproduktion föreslås tillsats av ett starkare oxidationsmedel än syre, följt av en avskiljning av utfällda oxider. Alternativt föreslås en fällning och flockning samt sedimentation/flotation följt av filtrering av råvattnet från både ytvattentäkten och grundvattenbrunn.
78

Sustainable development analysis of national methods of assessing potentially contaminated sites

Holmström, Christina January 2010 (has links)
In this thesis, several national methods used for investigating and/or assessing potentially contaminated sites have been analysed from a sustainable development perspective. To add a practical perspective to the analysis, a case study of the Swedish method’s initial site investigation was performed. The aim was to see how the national methods take the sustainable development aspects into consideration and based on the results see which method that would be most suitable when working towards sustainable development. The results showed that the methods do take the aspects of sustainable development into consideration. Based on how the aspects were taken into consideration, the methods used in the United Kingdom (England and Wales) and Norway are considered to be the most suitable when working towards sustainable development. The case study showed that differences between the theoretical and practical work can be found, and that the economic aspect in particular is given more priority in praxis.
79

Nutrients and runoff in a small catchment during spring 2010

Skoog, Peter, Bodin-Sköld, Henrik January 2010 (has links)
Eutrophication is an increasing problem in the Baltic Sea and is caused by an excess of nutrients in the water which are primarily transported with the runoff from cultivated land. The peninsula Vikbolandet in Östergötland is dominated by arable land and has stream outflows to the bays of Bråviken and Slätbaken. In this study five streams of Vikbolandet have been sampled during the spring flood period with the aim of connecting concentrations of nutrients in the streams with turbidity and runoff in the catchment. This analysis has then been related to the land use in the small catchment of Vadsbäcken in order to investigate the impact of land uses with areal losses of phosphorus. The results indicate that there are increasing concentrations of phosphorus downstream in the sites of Vadsbäcken and that the transported amounts of phosphorus increases with the spring flood and at a rainstorm event. It is shown that the distribution of agricultural blocks in the catchment of Vadsbäcken has a major impact on the nutrient leakage. There is a co-variation between turbidity and runoff during a rainstorm event and between particulate-bound phosphorus and runoff over time. A further aim has been to investigate possibilities for use of an easily managed, cost-effective environmental monitoring method for nutrient measurements in watercourses. Within four out of five streams at Vikbolandet there is a significant co-variation between turbidity and total phosphorus. Using field measurements of turbidity for environmental monitoring could provide a viable alternative for environmental monitoring of watercourses but will need further investigations of co-variation before being brought into use. Further, this study shows that the transport of phosphorus is underestimated in environmental monitoring
80

Transport of Multi-Walled Carbon Nanotubes in Saturated Porous Media

Dixiao, Bao January 2012 (has links)
Carbon nanotubes (CNTs) have been one of the most studied nanoparticles and incorporated into various consumer products. It has been reported that CNTs can enter groundwater systems by accidental or intentional release into the subsurface. As transport mechanisms of CNTs are not well understood, investigation on mobility of CNTs in the subsurface will be helpful to define disposal regulations of CNTs. The objective in this study is to investigate the effect of solution chemistry (pH and ionic strength) and physical factors (collector grain size and flow rate) on the transport of multi-walled carbon nanotubes (MWCNTs). One-dimensional convection-dispersion model incorporated with collector efficiency for cylindrical nanoparticles was used to simulate the transport of MWCNTs in porous media. It was observed that higher pH led to increase in mobility of MWCNTs. The critical point of ionic strength for MWCNTs getting mobilized was narrowed down in the range of 2 to 5 mM. It was observed that the finer porous media could retain more nanoparticles. The decrease in pore water velocity resulted in a clear retardation, lowered the hydrodynamic force acting on the particles and led to more retention.

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