• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 432
  • 332
  • 71
  • 64
  • 20
  • 20
  • 13
  • 9
  • 8
  • 7
  • 6
  • 3
  • 3
  • 2
  • 2
  • Tagged with
  • 1124
  • 1124
  • 304
  • 291
  • 277
  • 179
  • 168
  • 154
  • 144
  • 129
  • 129
  • 124
  • 105
  • 92
  • 87
  • 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

Model upravljanja otpadom zasnovan na principima smanjenja negativnog uticaja na životnu sredinu i ekonomske održivosti / Waste Management Model Based on Principles of Reduction of the Negative Impact on Environment and Economic Sustainability

Mihajlović Višnja 11 March 2016 (has links)
<p>U okviru disertacije, razvijen je model upravljanja otpadom na nivou regiona Novi Sad, kori&scaron;ćenjem analize tokova materijala i diskontovanih novčanih tokova. Model omogućava da se na osnovu identifikovanih količina otpada, koje je potrebno tretirati kako bi se ispunili ciljevi propisani Direktivama Evropske unije (EU), kvantifikuje uticaj upravljanja otpadom na životnu sredinu kroz emisiju CO2 eq. u atmosferu. Na osnovu identifikovanih količina otpada, model omogućava procenu investicionih i operativnih tro&scaron;kova postrojenja za tretman otpada. Dobijene ekonomske vrednosti mogu se optimizovati kako bi se uspostavio ekonomski održiv sistem upravljanja otpadom na dug rok uvođenjem naknade za tretman otpada. Razvijeni model i dobijeni podaci omogućavaju definisanje budućeg pravca razvoja sistema upravljanja otpadom u regionu čijom implementacijom bi se smanjio negativni uticaj na životnu sredinu, uspostavio ekonomski održiv sistem i ispunili ciljevi EU.</p> / <p>Using the method of analysis of material flows and discounted cash flows a<br />model for waste management for the Novi Sad Waste Management Region is<br />developed. Using the identified waste quantites in the region, model estimates<br />the waste quantites in order to meet the objectives in the Directives of the<br />European Union (EU) and quantify their impact on environment through the<br />emission of CO2 eq. in the atmosphere. In addition, based on the identified<br />amount of waste, the model estimates investment and operational costs of<br />waste treatment plants. Obtained economic values in the model can be<br />optimized in order to establish a waste management system that is<br />economically sustainable introducing the gate fee. The developed model could<br />be used as a tool for development of waste management system in the region<br />which will reduce the negative impact on the environment, will be economically<br />sustainable and fulfill the objectives of the EU Directives.</p>
482

Waste to Value : A study of reverse logistics system for Post-consumer textiles in Nässjö municipality

Rashid, Affan, Venskute, Ruta January 2017 (has links)
Background:   The demand of textiles and clothing is constantly increasing; as a result the post-consumer textile waste increase as well. This point is bringing the focus on creating the value from waste by recycling. Sweden, municipalities are responsible for handling the textile waste that is currently categorized as the household waste. The post-consumer textile when disposed is mixed with the other household waste, which eliminates the commercial value of the material Purpose:          The purpose of this study is to explore the current system in Nässjö municipality to manage post-consumer textiles and identify the possibilities for value creation through reverse logistics processes.  Method:          To fulfil the research purpose a qualitative study employing single case is used. Study caters multi-perspectives from different actors i.e. municipality, logistics service providers and consumers. Purposive sampling is used to select the respondents from each actor seeing their position in the companies and knowledge on the subject. Primary data is gathered by conducting 11 semi-structured interviews and field visit to the waste collection site. Secondary data is obtained using web sources and also from different project reports from government and other agencies. The empirical data is categorized and then analysed by thematic analysis with the developed theoretical framework of systems’ theory. Findings:         Legislation to collect textiles as the separate entity and put it in the reverse logistics system is on the way. Today, input in the system is very low due to the unawareness of consumers about the available options. Municipality is processing the waste as a normal household waste and it is incinerated to produce energy for the residents.  LSP are coordinating with municipality and tend to increase their resources for effective participation in the new system. Municipality requires strategic changes to meet the coming legislative requirements. Conclusion:     A sub-system could be developed for post-consumer textile in Nassjo municipality. Input in the system has to be determined by consumers education and convenience. Municipality has to define their roles for manage sub-system effectively. The study has provided the rich description of potential possibilities in this context.
483

Re-defining data visuals for an efficient and sustainable food waste management

Singh, Suhas January 2017 (has links)
The use of visual data representation is increasing the possibilities to exchange information and communicate indifferent contexts all over the world. Communicating food wastage visually to influence consuming patterns isone of these possibilities. Food wastage is currently a much-prioritized topic in Sweden as well as globally due toits negative impacts on society, environment and the economy, and therefore there is much need to bringinnovative solutions supporting reduction of food waste. This thesis presents a qualitative research based on a casestudy of food waste management at Sala municipality in Sweden while exploring the current visual datarepresentation techniques and its further potential to make food waste management more sustainable. The researchframework used in this thesis is based on visual rhetoric and the innovation theories. The thesis analyzes foodwastage from an international perspective, its connection to sustainable development goals and how MatomaticAB uses a visual data representation tool to address food wastage.The thesis further explains how the users associated with Sala municipality interpret the existing tool, thechallenges they face and review their expectations to build a new visual data representation model. The results ofquestionnaires filled by user’s, state that 50% of the respondents understand the current tool to its full capacityand only 50% of the respondents are satisfied with the overall tool. When it comes to the choice of datapresentation 67% of the users showed interest in use of infographics instead of the conventional bar graphs, andtherefore some parameters like, making the tool more interesting using infographics, user friendly by limiting thedata displayed and interactive by giving user options to explore further as per their liking, were thought whiledesigning the new visual data representation model.
484

Strategiskt arbete med att minska invasiva växtarters spridningsrisker : Klimatförändringar och trädgårdsavfallets inverkan på spridning

Lilja, Grace, Appelgren, Victoria January 2019 (has links)
Invasive species are an increasing problem worldwide, threatening indigenous communities and species. In a world where people travel and trade a lot in a global market, many organisms are transported to new parts of the world where they have never existed before. Most do not survive in the new environment but die, but some thrive and thrive. When such species are established and multiply in places outside their natural range, it can be followed by negative consequences for species that have existed there for a long time - so-called indigenous species. Then the new species are often called alien invasive species. An example of this is the beautiful and colourful plant flower lupin (Lupinus polyphyllus)that people on their travels brought with them from North America, among other things, Europe. Global warming and increased trade between countries is the main reason why foreign species are introduced to new ecosystems while climate change means that habitats can change to become more suitable for an invasive alien species. The invasive species currently causes major economic losses worldwide. Lupins, park slides, and giant sheds are examples of invasive plants that have been introduced in European gardens because they are beautiful and easy to care for. They are also invasive, spread aggressively and are detrimental to our nature because they penetrate our native species. To stop these invasive plants and from damaging Europe's nature, the EU countries have decided to take action against certain species. On January 1, 2015, the EU adopted a regulation on invasive alien species and how to combat it within the Union. On February 5, 2016, the Swedish Environmental Protection Agency submitted the Authority's proposal to the Swedish Government on new rules and measures on how to stop invasive harmful species. Already today, great resources are being devoted to combating invading plants such in our nature reserves. However, an early preventive or direct targeted intervention is much more cost effective than a continuous control of unwanted, invasive species with well-established populations. In order to succeed in this, we need an increased awareness of the problem of alien, invasive species among the public and decision makers, but also a sharp global analysis. Only with knowledge and continuous monitoring can we put in early action against future, aggressive invaders.
485

Establishing a process to reduce, recycle and reuse the waste electrolyte from fluorine generation

Fourie, Elna 17 November 2006 (has links)
MSc dissertation - Faculty of Engineering and the Built Environment / Waste electrolyte from fluorine cells is a major waste problem for the fluorine chemical industry. Processes have to be developed to reduce, recycle and re-use the spent electrolyte that has up to now been stockpiled. This dissertation is a compilation of the research work that has been done to derive a process to treat waste electrolyte for re-use. Different conversion processes were investigated to develop a Waste Management plan for the fluorine generating facility in respect of the electrolyte. Gravity settling, centrifuging, filtration, the addition of KF.HF to the to the electrolyte to decrease the HF concentration in the electrolyte and consequently decrease the solubility of Fe, Cu and Ni and addition of NaOH to the electrolyte to convert soluble Fe to the insoluble triple salt were tested. Gravity settling and centrifuging were shown to produce the best solution. However, significant sedimentation of the insoluble metal impurities in the electrolyte is timeously. The implementation of sedimentation as an industrial separation process to purify waste electrolyte of excess metal impurities is therefore impractical. The results indicated that sparging molten electrolyte with N2 gas to remove HF (thus precipitating soluble Fe, Cu and Ni, and removing moisture to reduce corrosion of metal components), followed by sediment centrifuging, appears to be a practical basis for an industrial waste electrolyte treatment process. During an assessment carried out by the Economics Trends Research Group (ETRG) (3) at the University of Cape Town a strong argument was made for the need to direct companies in South Africa to address environmental concerns with high priority. In South Africa there is very little awareness of the concept of Clean Technology. Not only must the level of contamination be reduced before waste is released into the environment, but natural resources like water must be conserved, and energy consumption must be reduced. Public concern over degradation of the environment can no longer be ignored. Globally, the chemical industries are considered to be the main culprits in the degradation of the environment. The assessment carried out by the ETRG showed that the chemical industries are classed among the top 5 generators of toxic and hazardous waste in every country. The metallurgical sector (mining) is in most cases classed as the top waste generator. Development and implementation of technologies that are more efficient are not a matter of choice any more. Each new facility that is developed should meet the challenge of generating as little waste as possible. Unfortunately, many old industries and facilities did not focus on increasing efficiency and minimising waste. These old facilities experience a challenge now to develop technology to make them part of this Cleaner Production and Technology era. Cleaner Production implies generating less effluent or waste and recycling waste to be used as raw material in the same or another facility. Cleaner Production also concentrates on the increase of efficiency but this is often limited by the chemical properties of substances. This research was based on the ideas for implementation of Cleaner Production in the fluorine generation facility at Necsa. Waste reduction almost always implies investment in equipment and development of new technologies. However there is ample evidence to show that the cost of rehabilitation of contaminated environment is exceedingly high in comparison with the precautionary steps taken to prevent contamination. Waste/Effluent Management have become new buzz words in the industrial environment.
486

The policy and practice of reclaimer integration in the City of Johannesburg

Sekhwela, Maite Mmakgomo January 2017 (has links)
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science (Geography). Johannesburg, 11 June 2017. / Reclaimer integration in South Africa has been identified as a priority, but how to integrate reclaimers remains a challenge. Crucially, there is not yet a coherent approach or a clear understanding of what reclaimer integration means in South Africa, let alone whether this same understanding of integration is shared by the reclaimers who are being integrated. By focusing on the integration initiatives of the Environment and Infrastructure Services Department (EISD) and Pikitup, this thesis conducts a comparative study of two reclaimer integration projects in Johannesburg. It investigates the breakdown and mismatch of understandings between social actors who do not share the same view of integration and implications thereof. In doing so, it contributes to discourse on the transformation of Johannesburg’s waste management system. Social constructivism theory by Berger and Luckmann (1966) provides the theoretical grounding for this dissertation by exploring how different milieus and experiences shape people’s understanding of realities. Findings illustrate that there is no clear conceptualisation of integration that underpins waste management policy. Drawing on social constructivism theory, the paper concludes that integration is a socially constructed and contested concept. Essentially, there are inconsistent understandings of integration among different groups of reclaimers as well as officials. For that reason, integration programmes created a new form of exclusion and imposed negative effects on reclaimers. KEYWORDS: Integration, Reclaimers, Waste, Policy, Recycling, cooperatives / LG2018
487

A destinação dos resíduos sólidos domiciliares em megacidades: o caso de São Paulo / Household waste management in megacities: the case study of São Paulo

Ruberg, Claudia 09 February 2006 (has links)
A alta complexidade da destinação dos resíduos sólidos nas megacidades, como é o caso do Município de São Paulo advém, não apenas da grande quantidade de resíduos gerados, mas também da sua extensão urbana.Os dois aterros sanitários localizados na periferia da Capital paulista – Bandeirantes e São João – recebem, diariamente, doze mil toneladas de resíduos urbanos, dentre as quais quase nove mil de resíduos domiciliares. Esses aterros ocupam, respectivamente, 140 e 85 hectares e estarão esgotados até o início da próxima década. O mero afastamento dos resíduos, destinação amplamente empregada nos municípios brasileiros, tem se mostrado como uma opção pouco viável nas megacidades, principalmente devido aos problemas urbanos a ele associados. Faz-se mister reduzir, significativamente, o volume de resíduos enviados aos aterros, meta não alcançada somente com o emprego da reciclagem. Através da incineração tem-se a redução necessária, sendo essa tecnologia já utilizada em diversos países.Com objetivo de modificar a atual destinação dos resíduos domiciliares de São Paulo para um sistema de estações redutoras de volume associado ao sistema viário principal, foi elaborada a proposta de implantação de seis incineradores localizados nas imediações de um anel viário metropolitano. Em cada unidade foi previsto um buffer de vegetação com a finalidade de minimizar os ruídos e os particulados no entorno, bem como proteger visualmente a área.A distribuição de unidades de redução de volume de resíduos permitiu a montagem de um sistema mais racional de transporte, com a eliminação das estações de transferência de resíduos e a diminuição das distâncias de transporte.Essa proposta, que respeita o zoneamento e as áreas de proteção ambiental, visa diminuir a dependência de grandes áreas para aterramento dos resíduos, reduzir os problemas resultantes do deslocamento de veículos coletores, ao mesmo tempo em que minimiza os efeitos negativos ao meio ambiente. / The extreme complexity of the solid waste management in mega cities like São Paulo is caused not only by the great amount of waste the city generates, but also by its huge urban area.The two existent sanitary landfills located in the outskirts of the city of São Paulo – namely Bandeirantes and São João – receive twelve thousand metric tons of urban solid waste daily, almost nine thousand metric tons of which are originated by household waste. These sanitary landfills occupy 140 and 85 hectares respectively, and it has been prognosticated that both areas will close before the next decade. The simple waste removal to areas outside the urban perimeter, a waste management concept implemented by most Brazilian cities, has been proved inefficient when mega cities are concerned, mainly due to urban problems associated with it. It is then necessary to reduce significantly the amount of waste sent to the sanitary landfills, a goal that has not been reached by simply recycling the waste. The technology of incineration on the other hand is an alternative that promotes this reduction and has been successfully used in many countries. A proposal has been devised to change the present management of household waste in São Paulo city to a system of reduction stations of the amount of waste linked to the main metropolitan road system. This proposal consists on the implementation of six incinerators placed in the vicinity of the metropolitan ring road. Each unit includes a vegetation buffer that both reduces the noise and particulates in the surroundings, and protects the area from visual pollution. The distribution of waste reduction units allowed the implementation of a more rational system of transportation, resulting in the elimination of the waste transfer stations and the shortening of the transportation distances. This proposal pays heed to the zone division of the city and the areas under environment protection, and aims at reducing the destination of large areas to the burying of waste as well as reducing the problems caused by the flow of the collecting vehicles, at the same time that it lessens the negative effects on the environment.
488

Desenvolvimento de metodologia para a caracterização de fontes radioativas seladas / Development of methodology for the characterization of radioactive sealed sources

Ferreira, Robson de Jesus 15 September 2010 (has links)
Fontes radioativas seladas são largamente empregadas no mundo. A Agência Internacional de Energia Atômica AIEA estima em dezenas de milhões de fontes radioativas no mundo. No Brasil, este número é próximo de 500 mil unidades, considerando-se as fontes de pára-raios e detectores de fumaça. Uma fonte selada pode tornar-se desnecessária, seja devido ao seu decaimento ou outro motivo, sendo classificada como fontes radioativas seladas fora de uso (FRS). No Brasil, a maioria das FRS é considerada rejeito radioativo e são encaminhadas a um dos institutos da CNEN. Sem uma estratégia definida para a deposição das FRS, estas são armazenadas aguardando uma solução. A Gerência de Rejeitos Radioativos - GRR do IPEN-CNEN/SP é o principal centro de recepção desse material e até meados de 2010 havia recebido cerca de 14.000 fontes. O processo proposto para a gestão dessas FRS consiste em retirá-las de suas blindagens originais e transferi-las a outra blindagem, projetada para esse fim. As operações de transferência são realizadas em uma cela quente, garantindo a segurança radiológica. Uma das exigências da CNEN é que todas as fontes seladas sejam caracterizadas. No processo estudado, a avaliação da atividade de cada fonte será feita utilizando-se um detector, do tipo câmara de ionização tipo poço. O presente trabalho tem por objetivo desenvolver uma metodologia para aferir ou determinar a atividade de FRS armazenadas na GRR de acordo com sua geometria e determinar suas incertezas. / Sealed radioactive sources are widely used in many applications of nuclear technology in industry, medicine, research and others. The International Atomic Energy Agency (IAEA) estimates tens of millions sources in the world. In Brazil, the number is about 500 thousand sources, if the Americium-241 sources present in radioactive lightning rods and smoke detectors are included in the inventory. At the end of the useful life, most sources become disused, constitute a radioactive waste, and are then termed spent sealed radioactive sources (SSRS). In Brazil, this waste is collected by the research institutes of the Nuclear Commission of Nuclear Energy and kept under centralized storage, awaiting definition of the final disposal route. The Waste Management Laboratory (WML) at the Nuclear and Energy Research Institute is the main storage center, having received until July 2010 about 14.000 disused sources, not including the tens of thousands of lightning rod and smoke detector sources. A program is underway in the WML to replacing the original shielding by a standard disposal package and to determining the radioisotope content and activity of each one. The identification of the radionuclides and the measurement of activities will be carried out with a well type ionization chamber. This work aims to develop a methodology for measuring or to determine the activity SSRS stored in the WML accordance with its geometry and determine their uncertainties.
489

Potencial de resíduos madeireiros gerados em Roraima para a produção de energia e carvão vegetal / Potential of wood residues generated in Roraima for the production of energy and charcoal

Morais, Weslley Wilker Corrêa 05 December 2018 (has links)
De acordo com o Plano Nacional de Resíduos Sólidos - PNRS, a destinação de resíduos industriais é de responsabilidade do seu gerador. Serrarias do estado de Roraima enfrentam uma série de dificuldades para cumprimento desta norma, principalmente, pela falta de informações e ausência de estudos que comprovem alternativas viáveis específicas para a região. Sabe-se, contudo, que de uma forma ampla e genérica, alternativas poderiam ser propostas. Dentre elas, a conversão direta dos resíduos para geração de energia e a pirólise visando a produção de carvão vegetal e seus co-produtos. Neste sentido, o objetivo geral deste estudo foi identificar, caracterizar e realizar análises a isto vinculadas, considerando os resíduos madeireiros gerados nas serrarias localizadas no pólo de Rorainópolis, Roraima, Brasil. Foram realizadas aferições da granulometria, umidade, composição química, densidade e poder calorífico do material in natura (CAPÍTULO 1). Ainda sobre este material foram realizadas carbonizações à temperatura de 450°C e 650°C e avaliação do carvão vegetal e gases do processo (CAPÍTULO 2). Além disso, foram avaliadas as características físicas, químicas, energéticas dos resíduos obtidos em diferentes seções das pilhas preexistentes nas serrarias (CAPÍTULO 3). / According to the National Solid Waste Plan - PNRS, a destination of industrial solid waste is responsibility of it generator. Roraima\'s sawmills face a series of difficulties to comply this standard, mainly for lack of studies proving feasible alternatives specific to region. It is known, however, that of broad and generic form can be applied alternatives. Among them, the direct conversion of the waste to the generation of energy and pyrolysis for the production of charcoal and co-products. In this sense, the general objective of this study was to identify, characterize and carry out related analyzes, considering the wood residues generated at sawmills located at the Rorainópolis Timber Hub, state of Roraima, Brazil. The granulometry, moisture, chemical composition, density and calorific value of the in natura material were measured (CHAPTER 1). Carbonisations were also carried out at 450°C and 650°C and charcoal and process gases were evaluated (CHAPTER 2). In addition, the physical, chemical and energetic characteristics of residues obtained in different sections of the pre-existing piles in the sawmills were evaluated (CHAPTER 3).
490

Proposta de implantação de um sistema de gestão ambiental no laboratório de rejeitos radioativos do IPEN-SP / Proposal of implementation of environmental management system the laboratory of radioactive waste in IPEN-SP

Moura, Luiz Antonio Abdalla de 28 March 2008 (has links)
Constata-se, atualmente, um uso crescente da energia nuclear no Brasil, para geração de eletricidade e outras aplicações (na medicina, na indústria, em agricultura, em técnicas ambientais, em radio-esterilização). Na realização das atividades de pesquisa do ciclo do combustível nuclear, em outras atividades de pesquisa, nas atividades industriais de produção de combustível e de energia e em todas as aplicações da energia nuclear, são gerados rejeitos radioativos, de atividades alta, média ou baixa. Atualmente, existem técnicas adequadas e seguras para o tratamento e armazenagem desses rejeitos, comentadas neste trabalho e que, sendo aplicadas, facilitam a aceitação da energia nuclear pela Sociedade. Com a crescente preocupação com o meio ambiente, a Organização Internacional de Normalização preparou e emitiu a Norma ISO 14.001 - Sistemas de Gestão Ambiental, aplicável a todos os tipos e portes de organizações, visando a melhoria de seu desempenho ambiental. Seus requisitos foram detalhadamente comentados neste trabalho, sendo particularizados para a sua aplicação no Laboratório de Rejeitos Radioativos do IPEN, como um estudo de caso. / An increasing use of nuclear technology in the form of its several applications (electricity generation, medical, industrial, agricultural, environment and radiosterilization) is currently being observed in Brazil. Radioactive waste of high, medium or lower activity is produced in all fuel cycle and other research activities, industrial activities of fiiel production and electricity generation. Appropriate and safe technologies are available for the treatment and storage of radioactive waste and, when applied, contribute for the acceptance of nuclear energy by the Society. With the increasing importance of demands related to environmental issues, the International Organization for Standardization issued the Standard ISO 14.001 - Environmental Management System, applied to all types and size of organizations, helping them to increase their environment performance. In this research, the standard requirements were commented in detail, being particularized to the Laboratory of Radioactive Waste from IPEN, as a case study.

Page generated in 0.109 seconds