• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 731
  • 198
  • 22
  • Tagged with
  • 951
  • 951
  • 951
  • 951
  • 871
  • 871
  • 372
  • 361
  • 216
  • 216
  • 138
  • 97
  • 83
  • 80
  • 80
  • 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.
481

Cultivating Social Capital in Thessaloniki : Contesting neoliberal governance on Urban Agricultural Gardens

Gallagher, Andrew January 2018 (has links)
The economic crisis of 2008 and subsequent implementation of austerity policies in Greece has had profound negative socio-economic impacts on Greek citizens. One way people seek to improve their socio-economic conditions is through participation in community organisations that have been studied for their ability to provide access to resources and representation. Through the application of a conceptual framework that connects the concepts of Social Capital and empowerment, this thesis investigates in what ways participation in Urban Agricultural Gardens (UAGs) in Thessaloniki benefits citizens. Specifically, the research aims to identify in what ways the formation of social relationships on these organisations produces and distributes Social Capital and whether this has empowering effects on individuals. The research positions itself within an ongoing discussion in what is referred to as a ‘neoliberal transition’, where in the last two decades social movements have increasingly contested forms of neoliberal governance and sought alternative forms of social organisation. Using empirical data from two Urban Agricultural Gardens in Thessaloniki, this thesis further investigates in what ways citizen empowerment may lead to contestations of neoliberal governance. While Social Capital was found to be generated at both organisations, there were differences in the ways it was produced and distributed. Stronger social ties were formed at PERKA due to an organisational structure that was conducive to social interaction. Similarly, narratives of contestation were found to be intensified by the physical and ideational practices at the organisation.
482

Utredning av lakvattnets ursprung på Brista deponi

Nordin, Joel January 2018 (has links)
Utredning av lakvattnets ursprung på Brista deponiJoel NordinBrista deponi har uppvisat oväntat höga lakvattenflöden trots att deponin har sluttäckts. Före sluttäckning var genomförd förväntades flödena reduceras till 700 m3 per år från flöden på några tusen m3. Brista deponi är belägen utanför Märsta i Mellansverige.Söder om deponikroppen finns lakvattendammar som är nyrenoverade med täta dukar från vilka förorenat vatten pumpas upp underifrån dammarna. Pumpningen sker då dammduken annars bucklar upp på grund av för högt grundvattentryck. Vattnet som pumpas upp är för påverkat, av främst närsalter, för att direkt släppas ut till recipienten vilket gör att det pumpas in i de befintliga dammarna. Syftet med detta arbete har varit att utreda ursprunget till de höga lakvattenflöden som fortsätter att rinna ut från deponin samt att utreda ursprunget till de föroreningar som pumpas upp underifrån lakvattendammarna.Marken under deponikroppen har undersökts genom att geologin från flera olika befintliga undersökningar och flygfoton har bearbetats i ArcMap och lagts in i programvaran Rockworks. I programvaran har en modell byggts upp och tvärsektioner över marken tagits ut och tolkats tillsammans med grundvattenytor. Utifrån modellen i Rockworks framkommer det att huvuddräneringen under deponikroppen ligger lågt i förhållande till dräneringen runt deponikroppen. Denna information tillsammans med att deponin inte har någon tät botten har lett till en slutsats att den huvudsakliga anledningen till de höga lakvattenflödena är inträngande grundvatten.Det påverkade vattnet under lakvattendammarna har undersökts med hjälp av programvarorna SIMCA, Rockworks och genom att studera analysserier av provtagningar på vattnet som pumpas upp och vatten från provpunkter på anläggningen. I SIMCA har analysserier lagts in från olika provpunkter i området t.ex. grundvattenrör, och en principalanalys genomfördes för att hitta mönster i föroreningsnivåer. Rockworks användes för att se relationen mellan dammarna, grundvattnet och geologin. Efter sammanställning av kemin, där närsalter varit den kraftigaste föroreningen, tillsammans med analys av redoxförändring, har de olika delarna från SIMCA och Rockworks vägts ihop med kemin. Sammanvägningen gav slutsatsen att det påverkade vattnet under lakvattendammarna härstammar ifrån tiden före lakvattendammarna renoverats och belagts med täta dukar. / Investigation of leachate water origin at the Brista landfillJoel NordinBrista landfill has showed unexpectedly high volumes of leachate out from the landfill even though it has been covered. Before the cover over the landfill was done, leachate volumes were expected to be 700 m3 after the cover would be finished compared to leachate volumes of a couple of thousand m3. Brista landfill is situated south of the city Märsta, in the middle part of Sweden.South of the landfill are newly renovated leachate ponds where polluted water is pumped up from beneath the ponds. The water is pumped up due to high pressure from the groundwater which makes the liner to buckle up if the water is not removed. The water is too polluted, mostly by nutrients, to be released to the recipient directly and is therefore pumped in to the ponds. The purpose of this project has been to investigate the origin of the high volumes leachate water from the landfill and to find an answer to the origin of the polluted water under the leachate ponds.The ground beneath the landfill has been investigated by putting the geology from several old investigations and aerial photos together in ArcMap and exported that information to Rockworks. With the help of Rockworks a model was build and cross sections of the soil could be produced with levels of the groundwater. From the cross sections, it can be seen that the main drainage under the landfill body is lower than the drainage that is around the landfill body. This information together with the information that the landfill doesn’t have any liner in the bottom, have concluded in the conclusion that the main reason of the high volumes of leachate water is due to groundwater intrusion.The polluted water beneath the leachate ponds have been investigated with the software SIMCA, Rockworks and by studying the test results from analyses of the water from different sample points on the facility, compared to the water that is pumped up. In the software SIMCA the test results from the different sample points, as groundwater wells, was imported and a principal component analysis was done to find patterns in the pollutants. Rockworks was used to see the relation between the ponds, geology and the groundwater. After revision of the chemistry, where nutrients were the biggest problem, together with studies of the redox change, the different parts from SIMCA and Rockworks has been weighted together with the chemistry. The parts combined led to a conclusion that the polluted water beneath the leachate ponds is derived from the time before the ponds was renovated and installed with liners.
483

Konduktivitet i vattendrag som indikator på sura sulfatjordar / CONDUCTIVITY IN RUNNING WATERS AS A METHOD OF IDENTIFYING ACID SULPHATE SOILS

Myrstener, Maria January 2012 (has links)
Increasing attention is being given to acid sulphate soils wherever they occur. The problems that leaching sulphate soils gives with significant lowerings of pH and mobilization of heavy metals influence large spectra of our society from fisheries to agriculture to construction. Mapping these soils is consequently of great importance and the methods of doing this is very much lacking in function and precision. This study was therefore carried out to investigate whether conductivity in running water can be used as a simple instrument to identify acid sulphate soils in the catchment. 31 coastal streams in the county of Västerbotten were analyzed for different catchment properties such as occurence of marine sediments and basic water chemistry including conductivity and sulphate. Sulphate proved to be the dominant factor controling conductivity in most streams, constituting up to 90 % of the anions. The results also showed that the concentrations of sulphate correlated to 67 % with marine sediments in the catchment. Where conductivity values exceeded 90 µS/cm the influence of acid sulphate soils could be determined for certain. The major conclusion drawn from this study is that high conductivity values serves as a reliable indicator of leaching acid sulphate soils whereas lower values can not exclude them. / flisik
484

Analys av ursprunget på löss från sen Pliocen – tidig Kvartär i Kina / Provenance Analysis of Loess from the Late Pliocene - Early Quaternary in China

Pettersson, Kevin January 2017 (has links)
The boundary between the Pliocene and the Quaternary marks a major transition in Earth’s climate, before which relatively warm climate prevailed and after which large scale glaciation of the Northern Hemisphere developed. In China a record of windblown dust deposits on the Chinese loess plateau forms loess sequences. These loess and red clay sequences cover the boundary between the Pliocene and Quaternary and a key question that needs to be answered is where the dust that has formed the loess comes from over this sequence transition and whether large global climate changes were matched by changes in dust source over this period. This can be hard to answer as often there are several places that may contribute dust to form a loess sequence. The goal of this project will be to investigate material from this boundary from the Chinese loess plateau to find out if there is a change in dust source. This will be achieved through XRF-analysis of several loess samples from a Quaternary-Pliocene site to examine the chemical components of the material, and with this information find out if it is possible to see a change in provenance. Weathering effects of the sequence will also be analyzed using the results. Analysis from the ratio of Al/Si, K/Al, Ti/AL and Ti/K indicates a possible change in dust source as the amount of Al increase compared to the other elements in the red clay. Proxies of weathering however gave vague or incomplete results. / Gränsen mellan Pliocen och Kvartär utgör en stor förändring av jordens klimat, då tidigare ett relativt varmt klimat hade dominerat ersattes nu av storskaliga glaciationer som utvecklades i den norra hemisfären. I Kina ligger ett arkiv av lufttranporterat stoft deponerat som löss på de kinesiska lössplatån för att forma löss sekvenser. Dessa sekvenser med löss och röd lera täcker gränsen mellan Pliocen och Kvartär och nyckelfrågan som måste besvaras är varifrån det stoft som bildat lössen kommer ifrån över denna övergång i sekvensen och om storskaliga globala klimatförändringar hade en inverkan på stoftkällan under denna period. Detta kan bli svårt att besvara då det oftast finns flera platser som kan bidra med stoft för att forma löss sekvenser. Målet med detta projekt kommer vara att undersöka material från denna gräns från den kinesiska lössplatån för att ta reda på om det finns en förändring i stoftkälla. Detta kommer utföras genom att göra en XRF-analys på flera lössprover från Kvartär-Pliocen för att undersöka den kemiska sammansättningen av materialet, och med denna information ta reda på om det är möjligt att se en ändring av källa för materialet. Även vittringseffekter i sekvensen kommer bli analyserade med hjälp av resultaten. Analys av förhållandet mellan Al/Si, K/Al, Ti/Al och Ti/K indikerade på en möjlig förändring av källa då mängden av Al ökade i den röda leran jämfört med övriga grundämnen. Undersökning av vittring gav däremot oklara eller ofullständiga resultat.
485

The behaviour of melt water within a glacial system

Tingdal, Love, Ceder, Nils January 2017 (has links)
A glacier contains of many different layers of different properties. Each layer is formed during a calendar year similar to tree rings and their layers. A glacier has two different zones, the first one referred to as accumulation zone, where the addition of snow exceeds the loss of snow. The second, the ablation zone, is the zone where the loss of snow exceeds the addition of snow. These two zones are divided by the equilibrium line, where the addition of snow equals the loss of snow. Lenses of ice, caused by the summer melt, usually divide the horizontal layers within the glacier from one another. During the winter, snow will accumulate on top of the glacier and during the upcoming summer, the same snow will partly melt due to solar radiation. Some of this meltwater will penetrate the ice lenses and the layers of snow beneath, while some of it will refreeze as the winter once again returns. As the seasons change, freshly fallen snow will be compacted and somewhat water saturated. Compaction will lead to air passages being sealed off into separate air bubbles, which also leads to a change in density; a fixed volume gets heavier due to ongoing compaction. Snow that gets compacted turns into firn which has a larger mass per volume than snow does. Further compaction leads to glacier ice. The purpose of this study is to determine what effect the ice lenses has on the permeating meltwater and whether differences in snow density have similar effects. To achieve this purpose, a glacier was simulated inside a freezing room, with the help of a box that was packed with a few layers of snow. The amount of layers represented the same amount of years for a natural glacier. The experiment was performed twice, once without ice lenses but with varying densities and once with ice lenses but with similar densities. The very top layer was dyed red to track the descending meltwater accurately. To cause the melting, five infrared lamps were used to simulate solar radiation on the very top. / En glaciär består av många olika lager med olika egenskaper. Var lager uppstår under ett kalenderår likt trädringar och de lager de består av. En glaciär har två olika zoner. Den första benämns som ackumulationszonen, där tillförseln av snö överskrider förlusten av snö. Den andra, ablationszonen, är den zon där förlusten av snö överstiger tillförseln av snö. Dessa två zoner skiljs åt av jämviktslinjen, där tillförseln av snö är lika med förlusten av snö. Islinser, som skapas av sommarens smältvatten, skiljer oftast de horisontella lagrena inom glaciären åt. Under vinterhalvåret ansamlas snö på glaciärytan och smälter delvis under sommaren av värme från solen. En del av detta smältvatten penetrerar islinserna och den underliggande snön, medan en del av det åter smälter under vintern. När säsongerna ändras kompakteras snön och blir delvis vattenmättad. Kompaktion leder till att passager inom isen separeras till enskilda luftbubblor, vilket också ökar densiteten; en specifik volym får högre massa på grund av ett ökat tryck. Snö som kompakteras övergår till firn, vilket har högre massa i förhållande till volymen än vad snö har. Fortsatt kompaktion leder till att firnen övergår till en glaciäris. Syftet med denna studie är att bestämma vilken effekt islinser har på perkolerande smältvatten och om skillnader i densitet hos snö har liknande påverkan. För att uppnå detta syfte simulerades en glaciär i ett frysrum, med hjälp av en låda som packades med några lager snö. Mängden lager representerade samma antal år i en naturlig glaciär. Experimentet utfördes två gånger, en gång utan islinser men med varierande densitet och en gång med islinser men med liknande densitet. Det översta lagret färgades rött för att kunna undersöka det sjunkande smältvattnet exakt. För att ge upphov till smältan användes fem infraröda lampor för att representera solens strålar längs ytan.
486

Kvarvarande grundvattennivåförändringar efter tunnelbygget genom Hallandsås

Fjällman, Elisabeth, Rylander, Viktor January 2016 (has links)
No description available.
487

Long-term glacier mass balance of Nordenskiöldbreen, Svalbard / Långsiktig glacial massbalans för Nordenskiöldbreen, Svalbard

Wiklund, Sara January 2016 (has links)
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.
488

Two Simple Soil Temperature Models: Applied and Tested on Sites in Sweden

Kjellander, Kalle January 2015 (has links)
No description available.
489

Status, trends and values of wintering and migrating birds in Gialova lagoon, Messenia, Greece

Norrby, Viggo January 2017 (has links)
Areas of wetland have for the last century declined globally, mostly as a cause of anthropogenic activitities. Since many bird species are depending on wetlands, this have affected their populations negatively, and today many of the remaining wetlands are protected. This study has investigated the status and trends of Gialova lagoon in Greece, both as a stopover for spring migrating birds and as a wetland for wintering waterbirds. This has been done by doing an own field inventory for two weeks in March, and by compiling and analysing data from winter censuses from the last thirty years. Results showed that Gialova supported many migrating birds during the inventory, and several of these are threatened in Europe. The eastern parts of the lagoon are the most important and sensitive areas, due to the suitable habitat for foraging and protection. The analysis of winter data showed that only one species was increasing, while the rest and the total amount of waterbirds were stable or decreased. The number of birds during winter did not reach thresholds for qualifying as a Ramsar-site of international importance. However, the wetland’s geographical location and context makes it a important area to protect for migrating birds, and it also has values for the local community in terms of different ecosystem services.
490

Abolishing Stockholm’s Public Transport Fares

Fuentes, Andrés January 2017 (has links)
The decrease of car emission levels has stagnated in the latter years in Stockholm, Sweden. Since the city’s publictransit system is highly developed via its large access to areas located in the city’s outskirts, it could serve as a tool topartially replace the city's car traffic and reduce emissions. This study therefore aims to examine expected travelbehavior changes from a fare-free public transport system and investigate potential limitations when increasing thepublic transport travel degree in Stockholm. The theoretical background consists of the mode choice theory thatdissects the reasons behind travel habits, and the zero-price effect which explains the effects from abolishing priceswhen purchasing a service product. The methodological approach was conducted through a random probabilitysurvey conducted in a face-to-face mix mode survey interviews in outdoor environments and via computer-assistedtelephone interviewing. The data was then analyzed through MS Excel and SPSS to extract patterns and correlations.The results thereafter implicated preferences from the survey participants implying their desire to primarily reduce orabolish the public transport fares, which would lead to significant travel habits changes among the majority ofrespondents. This would result in a high number of both frequent car drivers and frequent public transit commutersthat would commute more by public transit and drive less.

Page generated in 0.1379 seconds