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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.
1

Headfirst into shallow water - Wetland restoration and its contribution to the Habitats Directive

Brandt Korall, Elin January 2024 (has links)
Located in the borderland between aquatic and terrestrial environments, the wetlands cover a wide spectrum of habitats and enable living standards for a great variety of organisms. Although important habitats, a great extent of the original wetlands have disappeared in Europe and Sweden due to anthropogenic disturbances. In recent decades, there has been a significant increase in efforts to restore wetlands due to their popularity as a climate mitigation tool and their suggested multifunctional benefits. However, little is known about what kind of wetlands that have been restored in Sweden. Is it merely amphibian dams or is it fens and bogs? In this thesis, I have investigated whether the projects within LONA (The Local Nature Conservation Program) had contributed to reaching the aims of the Habitats Directive (79/409/EEC). My results showed that eleven (20 %) of the LONA projects from 2021-2022 contributed to favorable conservation status for five of the wetland habitat types listed in the Habitats Directive. In particular, there were positive impacts on Transition mires and quaking bogs (7140), and Bog woodland (91D0) from the hydrological restoration of peatlands. Although a major part of the projects rather resulted in novel ecosystems. A potential future challenge lies therefore in finding ways to increase the contribution to the Habitats Directive through the utilization of LONA funding. However, considering that LONA has unrelated aims and that other funding sources are better suited for this purpose, it is arguable whether this is the most suitable way forward. Hence, I propose adopting a landscape view that considers different funding sources and an integration of the expected ecosystem services in the national database with restored and created wetlands. With this approach, we can determine which wetland types to prioritize on a basin scale and identify the gaps where restoration of high-biodiversity wetlands is absent. Wetland restoration is a crucial aspect of conservation efforts, but if we are to reach the aimed functions, it requires careful planning, effective management, and long-term funding for future management.
2

Analyzing the impact of the financial systems for constructing wetlands in Sweden

Speks, Amanda January 2021 (has links)
Financial support is one of the main ways in which the Swedish government can encourage restoration and construction of wetlands. Despite having the tool of financial support for constructing wetlands in place, there is little information on how the support systems are structured and how they compare to each other. Another knowledge gap is the regional variation in wetland construction among counties and how this differs between them.  The purpose of this study is therefore two-part. Firstly, to map and compare the three main financial systems for constructing wetlands in Sweden, namely LOVA (the Local Water Preservation Grant), LONA (the Local Initiative for Nature Conservation) and the RDP (the Rural Development Programme). Results from the national comparison among financial systems shows that the RDP is the significantly most influential grant in wetland construction, whereas LOVA make up 9% and LONA 1% of the sum of hectares of constructed wetlands. These findings are the reason why this study only uses the RDP as a basis for the second purpose of this study, which is to investigate the regional variation in wetland construction. These results reveal two main findings, firstly that Skåne is the county with the most constructed wetlands, both in terms of hectares and number of wetlands. Finally, the purposes of the constructed wetlands which are financed by the RDP, are reviewed in this study. The purposes differ greatly between counties and do not necessarily align with the targets set in the Regional Action Plans.  The reasons for the large variations between counties, the low numbers of constructed wetlands within LONA and the administrative process of the RDP are topics which are recommended to research further.
3

Uso de aditivo microbiano e de filme plástico no controle da fermentação e da deterioração aeróbia de silagem de milho

Miyazaki, Michele Keiko [UNESP] 12 May 2008 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:30:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-05-12Bitstream added on 2014-06-13T19:39:38Z : No. of bitstreams: 1 miyazaki_mk_me_jabo.pdf: 327234 bytes, checksum: 17b4181adbb90ea06cfaf9d352747271 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O presente trabalho teve o objetivo de avaliar técnicas, como o uso de aditivos microbianos direcionados ao controle de microrganismos aeróbios, bem como a utilização de um filme plástico de baixa permeabilidade ao oxigênio no controle da deterioração aeróbia. No primeiro estudo, o objetivo foi avaliar o efeito do Lactobacillus buchneri sobre a composição química, o perfil de fermentação, a presença de fungos e de leveduras e a estabilidade aeróbia da silagem de milho. No segundo, objetivou-se avaliar as perdas de matéria seca, a composição químico-bromatológicas e a presença de fungos e leveduras das silagens de milho, na região periférica de silos superfícies, quando vedada com filme de baixa permeabilidade ao oxigênio. A inoculação influenciou o perfil fermentativo, indicando que o aumento da dose aplicada na massa ensilada reduziu a recuperação da MS e aumentou as perdas por gases. A composição bromatológica das silagens de milho não foi influenciada, no entanto ocorreu maior estabilidade aeróbia das silagens tratadas. O filme de baixa permeabilidade ao oxigênio reduz a ocorrência de leveduras e de fungos quando é imposto ao silo um avanço satisfatório da massa de silagem durante o desabastecimento, o que poderia melhorar a qualidade sanitária da mesma. / The present work aimed to evaluate techniques, as additives specific for aerobic microorganisms control and plastic film with low oxygen permeability for aerobic deterioration control. In the first study, the aim was to evaluate the effect of Lactobacillus buchneri on the chemical composition, the fermentation profile, the presence of fungi and yeasts and aerobic stability of corn silage. In the second, it was aimed to evaluate the dry matter losses, chemical-bromatologic compound and the presence of fungi and yeasts of corn silage, in the peripheral region of surfaces silos when forbidden to film from low permeability to oxygen. The inoculation influenced the fermentation profile, indicating that the increase of the dose applied in mass ensiled reduced the recovery of MS and increased losses by gases. The corn silage chemical composition was not influenced however there was greater aerobic stability of the treated silage. The low oxygen permeability film reduces the occurrence of yeast and fungi when it is imposed on a breakthrough satisfactory silo of the mass of silage during feedout rate, which could improve the health quality of the same.
4

Comportamento tribológico dos compósitos poliméricos utilizados no anel de atrito do amortecedor torcional de discos de embreagem / Tribological behavior of polymeric composites used ring of friction in the torcional damper of clutch disc.

Rosa, Avital Gabriel de Almeida 18 November 2017 (has links)
Submitted by Avital Rosa (avitalgabriel@hotmail.com) on 2018-01-23T16:54:36Z No. of bitstreams: 2 Dissertação de Mestrado_PPGCM _Aluno Avital Gabriel de Almeida Rosa.pdf: 5418816 bytes, checksum: f6f7f278fa5c0f54a96a91c4b6a87ad0 (MD5) Carta comprovante da versão final - Avital.png: 3621222 bytes, checksum: 7228740ac2bf0d70ebaad75deb22b89d (MD5) / Approved for entry into archive by Milena Rubi ( ri.bso@ufscar.br) on 2018-01-23T17:13:20Z (GMT) No. of bitstreams: 2 Dissertação de Mestrado_PPGCM _Aluno Avital Gabriel de Almeida Rosa.pdf: 5418816 bytes, checksum: f6f7f278fa5c0f54a96a91c4b6a87ad0 (MD5) Carta comprovante da versão final - Avital.png: 3621222 bytes, checksum: 7228740ac2bf0d70ebaad75deb22b89d (MD5) / Approved for entry into archive by Milena Rubi ( ri.bso@ufscar.br) on 2018-01-23T17:13:31Z (GMT) No. of bitstreams: 2 Dissertação de Mestrado_PPGCM _Aluno Avital Gabriel de Almeida Rosa.pdf: 5418816 bytes, checksum: f6f7f278fa5c0f54a96a91c4b6a87ad0 (MD5) Carta comprovante da versão final - Avital.png: 3621222 bytes, checksum: 7228740ac2bf0d70ebaad75deb22b89d (MD5) / Made available in DSpace on 2018-01-23T17:13:44Z (GMT). No. of bitstreams: 2 Dissertação de Mestrado_PPGCM _Aluno Avital Gabriel de Almeida Rosa.pdf: 5418816 bytes, checksum: f6f7f278fa5c0f54a96a91c4b6a87ad0 (MD5) Carta comprovante da versão final - Avital.png: 3621222 bytes, checksum: 7228740ac2bf0d70ebaad75deb22b89d (MD5) Previous issue date: 2017-11-18 / Não recebi financiamento / The three cylinder motors tend to vibrate more than the conventional four cylinder ones. In this new condition the transmission system and in particular the torsional damper of the clutch disc is subjected to sever wear and friction. The great challenge is to select new materials with low wear rate and adequate friction coefficient to attenuate this new vibration level. In this work three different candidate materials to be used as friction rings inside the torsional damper of clutch discs were tested in terms of wear resistance and friction. Two of the studied materials are currently used in the market (PA66 35 GF and NBR) in four cylinder motors and the third is currently used in clutch facing (NBR matrix composite). The materials were purchased from Schaeffler suppliers. The first step was the microstructural characterization and determination of the thermal stability of the three materials without the influence of friction. For that, the microstructure was analyzed by optical and electronic microscopy of Scanning (SEM), the amount of fibers and inorganic reinforcers was determined by burning tests and,the transition temperatures were determined by differential calorimetry. Two aging temperatures were studied 80 and 150oC. The effect of the ageing time was determined by hardness and infrared spectroscopy measurements. Among the three materials and clutch facing, they show a more stable structure in the temperature range between 80 and 150ºC. The PA66GF35 suffered changes in crystalline content and the NBR thermal degradation. The second step consisted in determining the wear characteristics of the material in bench tests with the objective of measuring the wear rate and friction coefficient of the material under extreme conditions of specific pressure and velocity (DIN50320, 1979). The results of the friction test had the following classification: NBR (0.13)> PA66GF35 (0.11)> clutch facing (0.09). Despite having a lower coefficient of friction, the clutch facing was the only material that achieved the minimum wear resistance required for the friction ring. Therefore the clutch facing is the best material for a 3 cylinder engine that requires a higher wear and thermal resistance on the clutch plate. / O motor de três cilindros tende a ter vibrações maiores que do motor de quatro cilindros. Nesta nova configuração o sistema de transmissão e, em particular, o amortecedor torcional do disco de embreagem fica sujeito a condições de desgaste e atrito mais severas. O grande desafio atual está na busca de componentes com baixo desgaste e um coeficiente de atrito adequado e que elimine os ruídos. Neste trabalho foram caracterizados os materiais utilizados na fabricação de anéis de atrito do amortecedor torcional de discos de embreagem quanto à resistência ao desgaste e atrito. Dois dos três materiais são hoje utilizados no mercado como componente de anel de atrito (PA66GF35 e elastômero NBR) em motores de quatro cilindros e o terceiro é atualmente utilizado em Lonas de embreagem. A primeira etapa consistiu na caracterização microestrutural e determinação da estabilidade térmica dos três materiais sem a influência de atrito. Para isso foram realizadas análises em microscopia óptica e eletrônica de varredura (MEV), teste de queima para porcentagem de fibra e tratamentos de envelhecimento, seguido de análises através de calorimetria diferencial, dureza, espectroscopia no infravermelho. Dentre os três materiais a lona de embreagem mostrou ser a mais estável na faixa de temperaturas entre 80 e 150ºC. O PA66GF35 sofreu alteração de cristalinidade e o NBR endurecimento devido à degradação térmica. A segunda consistiu na determinação das características de desgaste do material em função das variáveis de influência em condições controladas de laboratório. Para isso foi realizado um teste de bancada com o objetivo de medir a taxa de desgaste e coeficiente de atrito do material em condições extremas de pressão específica e velocidade (DIN50320, 1979). Os resultados do ensaio o atrito teve a seguinte classificação: NBR (0,13) >PA66GF35 (0,11)>Lona (0,09). Apesar de ter um coeficiente de atrito menor, a Lona de embreagem foi o único material que atingiu a resistência ao desgaste mínima exigida para o anel de atrito. Portanto a Lona de embreagem é o melhor material para um motor 3 cilindros que exige uma maior resistência ao desgaste e térmica, no disco de embreagem.
5

The determinants of local government involvement in nature conservation programs : Evidence from Swedish municipalities

Kessler, Marco January 2021 (has links)
Environmental degradation is a coining issue of our time. Hardly any place in the world is spared from its repercussions. Governments on all administrative levels have begun to take action. It has been acknowledged that local governments are playing a key role in combating the sources and adverse effects of environmental degradation. However, there is considerable variation in the extent to which local governments adopt environmental policies and activities. This paper investigates the determinants of local government involvement in the Local Nature Conservation Program (LONA), a nature protection initiative in Sweden, by analyzing a panel data set covering all 290 Swedishmunicipalities from 2010 to 2019. The study aims to contribute to the longstanding debate in the field whether economic or political variables matter more for explaining local differences in environmental policy adoption. For that purpose, four hypotheses have been derived from four competing theories of urban politics - capacity theory; the economic imperatives model; pluralist theory; and regime theory. The hypotheses are tested by building four statistical models using Poisson fixed effects estimation techniques and including functional form transformations and interaction effects. The results found cultural diversity in the local polity, political interest in the constituency, and socioeconomic characteristics of the residents to be the strongest predictors of municipal LONA-involvement. Contrary to previous research findings, municipal administrative capacity and population size are found to have no effect. The influences of fiscal capacity and political orientation of the governing coalition are ambivalent. Hence, whether economic or political variables are more important for LONAinvolvement is inconclusive. Findings suggest that both matter but that their explanatory power seems more pronounced when considering their joint effects. It appears that fiscal characteristics function as opportunity constraints but that the way local governments manage these circumstances is causing the differences between municipal LONAapplication outcomes. Moreover, it seems that LONA has been successful in engaging smaller and fiscally strapped municipalities by helping them overcome the barriers usually associated with these constraints.

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