• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 304
  • 108
  • 46
  • 42
  • 41
  • 21
  • 9
  • 5
  • 5
  • 4
  • 4
  • 3
  • 3
  • 2
  • 2
  • Tagged with
  • 716
  • 716
  • 114
  • 98
  • 87
  • 79
  • 69
  • 59
  • 56
  • 55
  • 55
  • 53
  • 52
  • 51
  • 51
  • 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.
471

O \'técnico-científico\' e o \'sociopolítico\' na gestão da água urbana: drenagem e manejo de águas pluviais no Município de São Paulo / Technical-scientific and sociopolitical aspects of urban water management: stormwater drainage in the city of São Paulo.

Borba, Maria Lucia Guilherme 23 April 2014 (has links)
Na cidade de São Paulo, as inundações, consideradas a consequência das chuvas intensas e da impermeabilização do solo urbano, têm causado impactos consideráveis. As contínuas e frequentes inundações e as intervenções para contê-las, de alto custo para o Poder Público, justificam a busca de uma abordagem complementar à puramente técnica-hidráulica, que dê atenção aos aspectos sociopolíticos inerentes à drenagem urbana e ao manejo de águas pluviais, o foco principal desta pesquisa. Seus objetivos são: uma análise crítica sobre a incorporação do sociopolítico na malha de disciplinas do curso de Engenharia Civil; uma análise crítica da visão dos profissionais envolvidos, direta ou indiretamente, com a gestão urbana sobre a incorporação de aspectos sociais no planejamento e na implantação de obras de drenagem urbana; e se estes aspectos são incorporados aos projetos de obras de drenagem e se atores sociais localizados na área de uma bacia hidrográfica valorizam esta incorporação. A pesquisa concluiu que, ainda que aspectos sociopolíticos estejam incorporados na malha de disciplinas dos cursos de Graduação em Engenharia Civil e ainda que os profissionais da gestão urbana valorizem os aspectos sociais tanto quanto os aspectos técnicos das obras de drenagem, o planejamento e a implantação de obras de drenagem em construção na área da bacia hidrográfica, foco geográfico desta pesquisa, não incorporam os aspectos relativos ao sociopolítico. A bibliografia consultada e os exemplos concretos apresentados mostram a importância da incorporação dos aspectos sociopolíticos nas intervenções. Os conceitos discutidos ajudaram a formular recomendações para a incorporação do sociopolítico na malha das disciplinas e nos projetos de obras hidráulicas. São recomendações que visam, além da preservação ambiental e do atendimento ao interesse público, maximizar os benefícios da solução técnica. / In the city of São Paulo, intensive rains and urban impervious cover are being held responsible for flooding events which have been causing increase in runoff volume and in peak discharge. The high costs of technical hydraulic interventions to contain the frequent flooding impacts justify the search for an alternative approach: the incorporation of the sociopolitical complexities of urban stormwater drainage, the main theme of this research. Its objectives are: understand if and how sociopolitical complexities are being incorporated to Civil Engineering education; how professionals directly or indirectly involved in urban stormwater management see the incorporation of sociopolitical complexities in planning and implementation of stormwater drainage construction works and, finally, if these complexities are integrated in the projects being planned and being implemented in an urban watershed area. The research concluded that Civil Engineering education incorporate courses which open space for the discussion of sociopolitical aspects; that professionals involved in urban management value the incorporation of sociopolitical aspects in planning and implementation of storm water construction projects, but that in the watershed area where projects are being implemented such aspects are not taken into account. The bibliography and the concrete examples examined show the importance of incorporating sociopolitical aspects in drainage construction projects. The concepts brought forward help identify recommendations for the incorporation of sociopolitical aspects in Civil Engineering education and in the planning and implementation of stormwater constructions projects. These are recommendations which aim at increasing environmental preservation, meeting the public interest and maximizing the benefits of the technical solution.
472

Optimal control of irrigation systems : an analysis of water allocation rules

Bright, John Charles January 1986 (has links)
A feasibility study of an irrigation development proposal should include an analysis of the effects of water supply conditions on the degree to which development objectives are expected to be realised. A method of making this analysis was developed based on procedures for solving two problems. These were; (a) optimally allocating a property's available supply of water among competing crops, and, (b) optimally controlling an open channel distribution system to meet temporally and spatially varying water demand. The procedure developed for solving (a) was applied. A stochastic dynamic programming procedure was developed to optimally schedule the irrigation of a single crop, subject to constraints on the timing of water availability and total application depth. A second procedure was developed, employing a constrained differential dynamic programming algorithm, for determining optimal irrigation schedules for use with variable application depth systems, and when several crops compete for an intra-seasonally limited supply of water. This procedure was called, as frequently as water supply conditions allowed, to provide short-term irrigation schedules in a computer simulation of the optimal irrigation of several crops. An application system model was included in these procedures to transform a crop water-use production function into the required irrigation water-use production function. This transformation was a function of the application device type and the mean application depth. From an analysis of the on-property effects of water supply conditions, it was concluded that in order to achieve high economic and irrigation efficiencies, water supply conditions must be sufficiently flexible to allow the application system operator to vary the mean application depth but not necessarily the time periods of water availability. Additionally, irrigation scheduling procedures which seek economically optimum strategies offer the potential to achieve a maximum level of net benefit at levels of water availability significantly lower than has previously been used for design purposes.
473

Making water information relevant on local to global scale – the role of Information Systems for Integrated Water Management

Hannerz, Fredrik January 2008 (has links)
<p>Relevant information is essential for finding solutions in Integrated Water Management (IWM). Complex water systems and a need for increasing integration of sectors, actors and scales in IWM require new methods for developing and managing such information. This thesis investigates the role of information within the IWM process, as well as the main challenges for development of representative, accessibleand harmonized information. Results show how information needs and the information production process for IWM may be systematized, and indicate a large potential for information system development for IWM. However, in order to reach the full potential, today’s limited and heterogeneous water information needs to become more comprehensive, transparent, interoperable, dynamic, scalable and openly accessible. Large pressures on water systems are found in coastal catchment areas that are unmonitored across the local to the global scale, indicating a large importance of these areas for nutrient and pollutant loading. The globally accessible runoff data from catchment areas that are rich in pressures from population, agriculture and general economic activity further exhibit a rapidly declining trend during recent years. Major water system changes may therefore pass unnoticed if analyzed on the basis of openly accessible runoff global data. Furthermore, large discrepancies are found between land cover databases, which may result in major uncertainties in quantification of water and evapotranspiration flows. Identified information challenges may be relatively easily overcome by making better use of available information, while other challenges such as development of consistent baselines of core data and a possible re-prioritization of water-environmental monitoring programs may be both difficult and costly.</p>
474

Local Cooperation in Water Management : A Minor Field Study from South India

Ståhlberg, Camilla January 2006 (has links)
<p>Decentralized development approaches have in recent years gained wide acceptance in policy circles. In India the national and the state</p><p>governments have for a long time undertaken the primary responsibility for water management. In recent years however, there has been a clear shift of policy towards increased reliance on the local communities. This thesis deals with the capacity of rural communities in India to manage their water resources in a sustainable way.</p><p>Through a case study of water management in a South Indian village opportunities and barriers for rural communities in India to manage their water resources in a sustainable way is analysed. The thesis deals with both formal and informal institutions involved in the water management.Factors that can promote and obstruct locals’ contribution in water management are discussed. Also the role of external actors such as NGOs, the Panchayats and the government is dealt with, and how they may facilitate a development towards sustainability and increased locals’ contribution in order to achieve a sustainable community bases water management.</p><p>Theories on collective action and the commons have been used in the analysis. These theories deal with how to get people to cooperate regarding the management of common resources such as water in order to achieve higher collective benefits. The study is primarily based on 66 semistructured qualitative interviews with local water users in a village in Andhra Pradesh.</p> / <p>Decentralized development approaches have in recent years gained wide acceptance in policy circles. In India the national and the state</p><p>governments have for a long time undertaken the primary responsibility for water management. In recent years however, there has been a clear shift of policy towards increased reliance on the local communities. This thesis deals with the capacity of rural communities in India to manage their water resources in a sustainable way.</p><p>Through a case study of water management in a South Indian village opportunities and barriers for rural communities in India to manage their water resources in a sustainable way is analysed. The thesis deals with both formal and informal institutions involved in the water management.Factors that can promote and obstruct locals’ contribution in water management are discussed. Also the role of external actors such as NGOs, the Panchayats and the government is dealt with, and how they may facilitate a development towards sustainability and increased locals’ contribution in order to achieve a sustainable community bases water management.</p><p>Theories on collective action and the commons have been used in the analysis. These theories deal with how to get people to cooperate regarding the management of common resources such as water in order to achieve higher collective benefits. The study is primarily based on 66 semistructured qualitative interviews with local water users in a village in Andhra Pradesh.</p> / The ISRN in the pdf-file is incorrect. The correct ISRN is shown below.
475

Making water information relevant on local to global scale – the role of Information Systems for Integrated Water Management

Hannerz, Fredrik January 2008 (has links)
Relevant information is essential for finding solutions in Integrated Water Management (IWM). Complex water systems and a need for increasing integration of sectors, actors and scales in IWM require new methods for developing and managing such information. This thesis investigates the role of information within the IWM process, as well as the main challenges for development of representative, accessibleand harmonized information. Results show how information needs and the information production process for IWM may be systematized, and indicate a large potential for information system development for IWM. However, in order to reach the full potential, today’s limited and heterogeneous water information needs to become more comprehensive, transparent, interoperable, dynamic, scalable and openly accessible. Large pressures on water systems are found in coastal catchment areas that are unmonitored across the local to the global scale, indicating a large importance of these areas for nutrient and pollutant loading. The globally accessible runoff data from catchment areas that are rich in pressures from population, agriculture and general economic activity further exhibit a rapidly declining trend during recent years. Major water system changes may therefore pass unnoticed if analyzed on the basis of openly accessible runoff global data. Furthermore, large discrepancies are found between land cover databases, which may result in major uncertainties in quantification of water and evapotranspiration flows. Identified information challenges may be relatively easily overcome by making better use of available information, while other challenges such as development of consistent baselines of core data and a possible re-prioritization of water-environmental monitoring programs may be both difficult and costly.
476

Responsible resource management in hotels : attitudes, indicators, tools and strategies

Bohdanowicz, Paulina January 2006 (has links)
Hotels constitute one of the main, and still expanding, pillars of the tourism sector and are highly unique among other commercial buildings. Resource intensive and frequently inefficient systems and operational routines applied in the sector, result in considerable environmental impact and indicate an urgent need for more environmentally sound practices and products in the hotel industry. A certain level of activity in the area of reducing resource use has been observed for quite some time but the motivation for this was related to cost-benefit issues rather than the environment. Furthermore, most of the initiatives are still considered to be best practice case studies and not daily routines. The constantly increasing prices of basic commodities, such as energy resources and water, encourage the implementation of energy and water efficiency and conservation measures in hotel facilities. To this end, numerous guidelines and initiatives have been produced by hotel-related organisations. The study of attitudes among 610 European hoteliers indicated that, at the moment, the level of environmental awareness among hotel managers is not high enough to introduce significant changes, although attitudes differ depending on the country of origin and the corporate policy. The prospects of significant cost savings, as well as customer demand were identified as the most likely parameters to enhance environmental responsibility among hoteliers. The popularity of CSR reporting and sustainability indices, especially among the larger companies, leads the author to believe that the industry is preparing to change. Many of the companies running hotels are also reporting their environmental management goals and indicators of environmental performance, while benchmarking and all types of comparison league tables are gaining popularity. There is, however, no system or methodology of data collection and monitoring that is universally accepted or applicable throughout the hotel sector. Furthermore, the accuracy and validity of the published performance indicators and benchmarks is widely debated due to large variations in the figures reported. The analyses performed on data from over 180 upscale and mid-market European chain hotels (Hilton International and Scandic) indicated that even among relatively uniform (service-wise) hotels the amenities offered did influence consumption, further complicating the concept and applicability of uniform benchmarking and resource consumption modelling. It was thus concluded that, creating a uniform model for all hotels is almost impossible, or would require a significant amount of very detailed input data, and that the results could still be highly inaccurate. Instead, it was suggested that it might actually be more accurate to develop models for individual hotels. Such an approach would allow for the modelling of the behaviour of all types of hotels with no size, type of services or standard limitations. Multi-variate step-wise regression analyses performed on individual Scandic hotels in Sweden indicated that energy consumption was dependent on the outdoor air temperature/actual heating degree days, while water consumption was mainly influenced by the number of guest-nights sold. Experience gained by the author during the process of the Hilton Environmental Reporting system upgrade allowed for the formulation of a set of rules of thumb that ought to be followed in the design of similar schemes. The experience of various regions and numerous companies also suggests that well designed and implemented environmental and resource management programs bring significant benefits at an individual as well as a corporate level. This study provides an indication of the strategies that can be used by various stakeholders in the process of development and implementation of such programs. This research further suggests that future developments in environmental performance indicators and benchmarking may best be served by disaggregating hotels into modules (such as guest-rooms, catering outlets, conference centres) and developing consumption models and best practice indicators for these particular components. The individual efficiencies/performance indicators should then be combined and weighted to provide a just overall evaluation of a facility that could then be compared to a benchmark (developed in the same manner). In a similar manner, sustainability assessment schemes and indicators for destinations and communities could be developed. However, more accurate and differentiated knowledge of the individual performance of sub-systems is necessary to proceed with such an alternative. In addition, the methodologies for data collection and reporting procedures, at all levels of the company and sector, need to be standardized and detailed / QC 20100818
477

Skillnader i vatten- och avloppshantering inom EU : En jämförelse mellan Slovakien och Sverige

Öhman, Camilla January 2010 (has links)
The management of water resources and waste water varies between the countries of the EU. For many years, a large part of the water in Europe has been contaminated by, among other things, insufficiently treated waste water and emissions from agriculture. The EU Water Framework Directive 2000/60/EC and the Urban Waste Water Directive 91/271/EEC are intended to harmonize fresh-water management and waste water management within the whole EU, aiming at safeguarding drinking water of good quality and a high quality of all water within the EU today and in the future. There are however some problems concerning the waste-water directive. One problem is the huge investment needed in Slovakia to fulfil the demands of the waste-water directive for waste-water management in larger communities (with more than 2000 inhabitants). Many waste-water treatment plants need to be upgraded or built, and in addition a large part of the households in eastern Slovakia are not yet connected to a municipal water-supply and waste-water collecting system (including waste-water treatment). Subsidies from the EU’s structural funds are needed for Slovakia to fulfil the requirements of the waste-water directive. Because this directive only applies to larger communities, smaller communities and private sewage are not affected by the directive and therefore, in general, not eligible for financial funding from EU. Financial funding, however, is needed for addressing inadequate sewage in small communities with poor socioeconomic and municipal financial resources. For water protection to be effective, it is important to take also private sewage emissions into consideration, even though they might appear insignificant. Point emissions from insufficient private sewage (private sewage systems with insufficient waste-water treatment or emission of untreated waste water), primarily in small, tightly clustered communities in Slovakia or for example in Sweden in areas where weekend houses are being converted into permanent dwellings, are potential sources of pollution that can cause health or/and environmental problems. Inadequate private sewage can thus reduce the quality of both surface and ground water and have a negative impact on aquatic ecosystems, which in turn makes it more difficult to reach the quality standards of the Water Framework Directive and its daughter directives. This applies to both Slovakia and Sweden. The private sewage solutions that are recommended today are often satisfactory but not without problems. To give an example, miniature waste water treatment plants are expensive to put in place, require technological knowledge on the part of the property owner and they also require a daily flow of waste water to function properly. Improper handling of the miniature water treatment plant may cause inefficient or no water treatment at all, in some cases the bacterial content of the waste water may increase instead of being reduced. To address the problem concerning private sewage it is important that (1) waste-water solutions are adapted to local circumstances and financial funding are given to economically week municipalities (2) the property owner (owner of the private sewage) regularly controls the quality of the out-going treated wastewater (if it is possible) and (3) that efficient inspections with injunctions (from authorities) are carried out to discover faulty private sewage. Unfortunately financial funding, in general, is not given to small municipalities and/or inappropriate private sewage and inspections, both in Slovakia and Sweden, are generally slow.
478

Effect Of Relative Humidity Of Reactant Gases On Proton Exchange Membrane Fuel Cell Performance

Ozsan, Burcu 01 May 2012 (has links) (PDF)
Fuel cells are expected to play a major role in the economy of this century and for the foreseeable future. The use of hydrogen and fuel cells can address critical challenges in all energy sectors like commercial, residential, industrial, and transportation. Fuel cells are electrochemical devices that convert energy of a chemical reaction directly into electrical energy by combining hydrogen fuel with oxygen from air. If hydrogen is used as fuel, only byproducts are heat and water. The objective of this thesis is to investigate the effect of operating temperature and relative humidity (RH) of reactant gases on proton exchange membrane (PEM) fuel cell performance by adjusting the operation temperature of the fuel cell and humidification temperature of the reactant gases. In this study, the effect of the different operating parameters on the performance of single proton exchange membrane (PEM) fuel cell have been studied experimentally using pure hydrogen on the anode side and air on the cathode side. Experiments with different fuel cell operating temperatures, different air and hydrogen humidification temperatures have been carried out. The experimental results are presented in the form of polarization curves, which show the effects of the various operating parameters on the performance of the PEM fuel cell. The polarization curves data have been fit to a zero dimensional model, and the effect of the fuel cell operation and humidification temperatures on the kinetic parameters and the cell resistance have been determined. The fuel cell has been operated with 1.2 and 2 stoichiometry ratio for hydrogen and air, respectively. Fuel cell performance was detected at different fuel cell operation temperatures changing from 60 to 80 &ordm / C, and relative humidity of the entering gases changing from 20 to 100 % for air and 50 % and 100 % for hydrogen. Tests were performed in a PEM fuel cell test station. The highest performance of 275 mA/cm2 at 0.6 V and 650 mA/cm2 at 0.4 V was obtained for 50 % RH air with a constant 100 % relative humidity of hydrogen for working at atmospheric pressure and 60 oC fuel cell temperature. However, the highest performance of 230 mA/cm2 at 0.6 V for 50 % RH of air with a constant 100 % relative humidity of hydrogen and the highest performance of 530 mA/cm2 at 0.4 V for both 70 % RH and 100% RH air with a constant 100 % relative humidity of hydrogen was obtained for working at atmospheric pressure and 70 oC fuel cell temperature. Besides, the highest performance of 200 mA/cm2 at 0.6 V and 530 mA/cm2 at 0.4 V was obtained for 100 % RH air with a constant 100 % RH of hydrogen for working at atmospheric pressure and 80 oC fuel cell temperature.
479

Water policy informatics : a topic and time series analysis of the Texas state water plans

Wehner, Jenifer Elizabeth 15 July 2011 (has links)
The disciplines of informatics and information visualization have developed in response to societal needs to find new insight in complex datasets and have been enabled by technological advancements. Joint application of these fields can demonstrate themes and connections that are otherwise not apparent. Methodological approaches, such as direct network analysis, can be applied to policy documents to determine if action or policy recommendations match the goals or objectives stated in the within the same documents. Informatics and information visualization can also be used to analyze changes of themes found within the documents over time. This paper seeks to leverage informatics and information visualization methodologies as a novel approach to policy analysis. In particular, directed network and time burst techniques are used to analyze water management policy documents for the State of Texas. The congruency between the stated goals or objectives and recommendations sections is evaluated at a topical level within each planning document and possible changes in important water policy concepts over time are highlighted by comparing among multiple planning documents. Although there limitations to the process at the time of publication due to the newness of the software utilized, this paper demonstrates that the products still lead to unique and insightful conclusions. / text
480

Gestion de l'eau en milieu urbain : étude de la ville de Québec entre 1840 et 1920 /

Labrecque, Annie-Claude January 2009 (has links)
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Page generated in 0.1222 seconds