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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.
11

Development of a multi-criteria approach for the selection of sustainable materials for building projects

Akadiri, Oluwole Peter January 2011 (has links)
Construction activity is known to have a major impact on the environment and is a major consumer of a wide range of naturally occurring and synthesized resources. Despite the recognition that environmental issues are important to the survival of the construction industry, the industry continues to degrade the environment, exploiting resources and generating waste, and is slow to change its conventional practices to incorporate environmental matters as part of its decision making process. With increased awareness and knowledge of these impacts, efforts are being made to avoid these adverse effects and to work towards impact mitigation. Among these is sustainable building material selection. Building material selection is an important issue in building design and construction decision-making and environmental issues need to be incorporated into the evaluation process. The research reported in this thesis was initiated to address these issues in the UK, towards developing an assessment model for incorporating sustainability into building material selection process. A questionnaire survey was conducted to investigate the level of awareness, knowledge and implementation of sustainable practices among architects and designers and how this impacts on their design decisions. To facilitate the implementation of sustainable practices into building material selection, a set of sustainable assessment criteria (SAC) for modeling and evaluating sustainability performance of building materials was developed. Building material can be assessed using an index system that combines the principal criteria of sustainable development. The derived criteria were assessed and aggregated into a composite sustainability index using the Analytical Hierarchy Process (AHP) technique which has been praised for its ability to incorporate both objective and subjective considerations in the decision process. The development of a sustainability index is a way of supporting decision makers faced with making numerous and sometimes conflicting evaluation as with building material selection. The methodology adopted in undertaking this research was the mixed method approach involving a detailed review of the relevant literature, followed by an industry-wide survey of UK architects and designers. Following this, case study was conducted to collect data for sustainability criteria used in the assessment model. The data collected were analyzed, with the aid of SPSS, Excel and expert choice software using a variety of statistical methods including descriptive statistics analysis, relative index analysis, Kendall’s concordance and factor analysis. The key finding was the existing gap between awareness and implementation of sustainable construction practices, which has led to failure of realizing the benefits of a sustainable approach to construction. The study showed a discrepancy between what architects and designers claim to be convinced about, and knowledgeable in, and their commitment and practices; they seem to be unable to translate their environmental awareness and knowledge into appropriate design decisions and are in need of a decision support system that can aid the incorporation of sustainability into building design. The model developed satisfy this gap and was validated by application to a roof covering material selection decision process for a case study building project by means of experts’ review via a survey and the findings obtained suggest that the model is valuable and suitable for use in practice. Finally, areas for further research were identified.
12

Avaliação do risco a perda da capacidade hidrica superficial atraves de analise espacial : estudo de caso na bacia do rio Jundiai Mirim

Picolo, Conrado Eugenio Borges 30 August 2005 (has links)
Orientadores: Carlos Roberto de Souza Filho, Jener Fernando de Morais Leite / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociencias / Made available in DSpace on 2018-08-05T08:21:53Z (GMT). No. of bitstreams: 1 Picolo_ConradoEugenioBorges_M.pdf: 3955298 bytes, checksum: cfe9d59f8c1d2f4be316895c7d4a394d (MD5) Previous issue date: 2005 / Resumo: A bacia do Rio Jundiaí Mirim, compreendida nos municípios de Jundiaí, Jarinu e Campo Limpo Paulista, embora seja considerada, na sua maior parte, como uma área de conservação ambiental, tem sido atingida por pressões antrópicas, incluindo ocupação desordenada, operações mineiras, práticas agrícolas inadequadas, desmatamento, entre outras. Cerca de 97% do abastecimento de água da cidade de Jundiaí, o principal pólo consumidor local, é captado dessa bacia. Apesar dessa situação preocupante do uso da terra na área da bacia, nenhum estudo consistente foi realizado até hoje sobre seu impacto potencial sobre o abastecimento de água na região. Nesse contexto, esta pesquisa teve como principal objetivo traçar uma metodologia de análise do risco a perda da capacidade hídrica da bacia do Rio Jundiaí Mirim em função da impermeabilização do solo ocasionada pela ação antrópica, relacionando características morfométricas da bacia à informações pedológicas e ocupacionais. Dois métodos básicos foram utilizados para integração e análise espacial dos dados: o Processo Analítico Hierárquico (PAR) (método dirigido pelo conhecimento) e a Regressão de Multivariáveis (RM) (método dirigido pelos dados). Mapas de favorabilidade da manutenção da capacidade hídrica da bacia foram gerados através do método PAR, retro-ajustado pelo método RM, para dois cenários: (i) ocupação atual da bacia e, (ü) ocupação máxima para manutenção da capacidade hídrica dos canais principais da bacia. A análise cruzada nem os mapas gerados para esses dois cenários permitiu a derivação do produto-alvo desse estudo: um mapa de classes de risco a perda da capacidade hídrica da bacia. Dez Cinco sub-bacias foram classificadas como de muito baixo e baixo risco a perda de suas capacidades hídricas. Segundo os critérios utilizados na análise e considerando as condições atuais de ocupação, a bacia do rio Jundiaí Mirim não apresenta áreas de alto risco quanto a sua capacidade de fornecer água para as cidades da região / Abstract: The Jundiai Mirim river watershed (JMRW) is comprised within the cities of Jundiaí, Jarinu and Campo Limpo Paulista. Although a large portion of this watershed is considered a site of environmental protection, the area has been increasingly submitted to anthropic-related changes, including intricate house settlement, mining operations, damaging farming practices, deforesting, etc. Some 97% of the city of Jundiaí water supply, the main consuming center in the area, comes :&om the JMRW. Albeit this improper land use within the watershed is widely acknowledged, there have been no comprehensive scientific investigations as regards the potential impacts and threats that such anthropic changes may inflict in the water supply of the region. In this context, the main objective of this project is to develop a method for risk assessment of the potential loss of the JMRW hydric capacity, focusing on the effects of soil impermeability driven by antropic events and considering the synergy between morphometric, pedological and landuse characteristics of the watershed. Two basic methods were employed for data integration and spatial analysis: the Analytical Hierarchy Process (AHP - a knowledge-driven method) and the Multivariables Regression (MR - a data-driven method). Maps of favorability of hydric capacity maintenance were produced through AHP, and the mo deI was retro-adjusted by MR calculations. Two scenarios were considered: (i) present occupation of the watershed; and (ii) maximum possible occupation within a protective limit to maintain the hydric capacity of the main rivers of the watershed. Cross analysis of the favorability maps created for these two scenarios yielded the aimed risk assessment map for the JMRW. Five sub-basins were classified within very low and low risk to loose their hydric capacity. Considering the criteria employed in this work and the existent pattern of landuse, the JMRW shows a situation of overall low risk and it has the necessary resources to keeping the water supply of the region / Mestrado / Metalogenese / Mestre em Ciências
13

Estimating the effectiveness of a mobile phone network's deferred revenue calculated through the use of a business automation and support system

Smuts, Francois 03 1900 (has links)
Thesis (MComm (Logistics))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Mobile phone networks form an integral part of economic and social development globally. Mobile phones have become an everyday part of life and it is hard to imagine a competitive economy without the availability of mobile communications. Emerging markets benefit most from the implementation of mobile technology and growth trends are outperforming earlier predictions. The most popular and sustainable payment model used by mobile phone networks in emerging markets is the pre paid mechanism used for the distribution of airtime. This mechanism brings about unique challenges for networks in emerging markets. In this thesis the importance of the mobile phone network pre paid value channel is introduced through an analysis of pre paid revenue. A brief introduction is given to the systems and products that contribute to the functioning of the pre paid value channel. The revenue generation process is described with regards to the pre paid sector of the market and an in-depth explanation of the importance of deferred revenue is given, how it is recorded and what role it fulfils in the generation of revenue. The complexity of the network environment, both technical and operational makes the use of a business automation and support system (BSS) a necessary tool for effective execution of tasks and processes within the network environment. These systems record information from a wide spectrum of available technical network resources and use this information to automate the flow of network products. The use of such a system for the calculation of deferred revenue is suggested. Saaty‟s Analytical Hierarchy Process (AHP) algorithm and the Elimination and Choice Expressing Reality (ELECTRE) method are used to compare the newly proposed method for the calculation of deferred revenue using a BSS. Using Saaty's algorithm to estimate the effectiveness of deferred revenue as reported through the use of a BSS yields favourable results for the proposed method. This helps to bridge the gap in the poorly researched mobile telecommunications industry. ELECTRE is used to substantiate the findings of the model using AHP and meaningful tests are done to motivate correctness and accuracy of the results obtained throughout. Most importantly, the findings were shared with academic and industry experts, adding meaningful resemblance to the goals set out to achieve. / AFRIKAANSE OPSOMMING: Mobiele foon netwerke is wêreldwyd 'n onlosmaakbare deel van ekonomiese en sosiale ontwikkeling. Mobiele fone is deel van ons alledaagse lewe en dit is moeilik om 'n kompeterende ekonomie te bedink sonder die beskikbaarheid van mobiele kommunikasie. Ontluikende markte trek die meeste voordeel uit die implementering van mobiele tegnologie en groeitendense vertoon beter as wat vroeër voorspel is. Die mees gewilde en volhoubare betaalmetode wat deur mobiele foon netwerke in ontluikende markte gebruik word, is die voorafbetalingsmeganisme wat vir die verspreiding van lugtyd gebruik word. Hierdie meganisme bring unieke uitdagings vorendag in ontluikende markte. Die tesis beskryf die belangrikheid van die mobiele foon netwerk voorafbetalingswaardekanaal deur 'n analise te maak van vooruitbetalingsinkomste. 'n Kort oorsig oor die sisteme en produkte wat bydra tot die funksionering van die vooruitbetalingswaardekanaal word verskaf. 'n Beskrywing van die inkomste-genereringsproses vir die vooruitbetaling-sektor van die mark word verskaf en 'n in-diepte verduideliking van die belangrikheid van uitgestelde inkomste, hoe dit vasgelê word en watter rol dit speel in die generering van inkomste word verduidelik. Die kompleksiteit van die netwerkomgewing, beide op 'n tegniese en operasionele vlak, maak die gebruik van 'n besigheidsoutomatisering en ondersteuningsisteem (BSS) 'n noodsaaklike instrument vir die effektiewe uitvoer van take en prosesse binne die netwerkomgewing. Hierdie sisteme stoor informasie vanuit 'n wye spektrum van beskikbare tegniese netwerkbronne en gebruik die inligting om die vloei van netwerkprodukte te outomatiseer. Die gebruik van sodanige sisteem word voorgestel vir die berekening van uitgestelde inkomste. Saaty se Analitiese Hierargie Proses-algoritme (AHP) en die Eliminasie en Realiteit-Deur-Keuse Uitdrukkingsmetode (ELECTRE) word gebruik vir die vergelyking van die voorgestelde metode vir die berekening van uitgestelde inkomste deur middel van 'n BSS. Die gebruik van Saaty se algoritme om die effektiwiteit te bereken van uitgestelde inkomste soos gemeld deur die gebruik van 'n BSS, lewer gunstige resultate vir die voorgestelde metode. Dit vul 'n leemte in die swak nagevorsde mobiele telekommunikasie industrie. ELECTRE word gebruik om die bevindinge van die AHP-model te substansieer en betekenisvolle toetse word deurentyd gedoen om die korrektheid en akkuraatheid van die resultate te motiveer. Die belangrikste aspek van die navorsing is dat die bevindinge gedeel is met kenners binne die akademie sowel as die industrie, wat nou aansluit by die doelstellings wat aanvanklik beoog is.
14

Generator maintenance scheduling models in power systems : integrated cost models for generator maintenance strategy under market environment

Al-Arfaj, Khalid Abdulaziz January 2009 (has links)
Change from a regulated to deregulated structure means that, the centralized maintenance system is not valid any more. In the surveyed published literature, there is not a single model which incorporates all maintenance cost components to analyze the effect of different maintenance strategies for generator companies (GENCOs). The work enclosed in this thesis demonstrates that there is a considerable requirement for accurately modelling cost components of the maintenance model, to be used in maintenance scheduling for deregulated power system, in order to attain a superior schedule with major financial and operational impact. This research investigates and models most cost factors that affect the maintenance activities of the deregulated GENCOs, and demonstrates the utilization of the developed cost models in maintenance scheduling. It also presents the data gathering process for the developed maintenance cost model. A generator maintenance scheduling model that considers direct and indirect maintenance costs, opportunity costs (i.e. loss of customer goodwill), effective maintenance strategies, failures, and interruptions is developed. A Genetic Algorithm (GA) based approach is employed to achieve maintenance schedules to various generators maintenance scenarios. An Analytical Hierarchy Process (AHP) approach is proposed for modelling customer goodwill. The maintenance model was redeveloped under the Reliability Centred Maintenance (RCM) strategy to analyze the effect of a maintenance strategy on maintenance costs. Case studies are presented to demonstrate the utilisation of the developed models.The investigation shows that the market prices, opportunity costs and maintenance strategy have an effect on the final maintenance schedule. The research demonstrates that the cost components are critical factors to achieve an effective maintenance schedule, and they must be considered and carefully modelled in order to reflect more realistic situation for maintenance scheduling of generator units in deregulation environment.
15

Avaliação de susceptibilidade de movimento de massa em linhas de transmissão: estudo de caso na região da Serra da Mantiqueira / Evaluation of mass movement susceptibility over transmission lines: case study at Serra da Mantiqueira region

Junqueira, Adriano Martins [UNESP] 18 January 2017 (has links)
Submitted by ADRIANO MARTINS JUNQUEIRA null (adriano@geopx.com.br) on 2017-03-11T20:17:10Z No. of bitstreams: 1 Mestrado - Adriano Martins Junqueira - 2017.pdf: 8109678 bytes, checksum: d1e6cf6e83e8eac0c87d3eb5b494f810 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2017-03-16T20:19:44Z (GMT) No. of bitstreams: 1 junqueira_am_me_guara.pdf: 8109678 bytes, checksum: d1e6cf6e83e8eac0c87d3eb5b494f810 (MD5) / Made available in DSpace on 2017-03-16T20:19:44Z (GMT). No. of bitstreams: 1 junqueira_am_me_guara.pdf: 8109678 bytes, checksum: d1e6cf6e83e8eac0c87d3eb5b494f810 (MD5) Previous issue date: 2017-01-18 / A maioria dos empreendimentos do setor elétrico brasileiro não apresentam uma avaliação sistemática espaço-temporal de suas estruturas para identificar vulnerabilidades ambientais nos empreendimentos. Assim, este estudo teve como objetivo analisar a susceptibilidade de movimento de massa em linhas de transmissão, na região da Serra da Mantiqueira, sujeitas aos efeitos de chuvas tropicais e operacionalizar uma plataforma dinâmica de análise e alerta nas áreas de maior criticidade. Para este trabalho, foram levantados dados estáticos e dinâmicos na região a partir de fontes de acesso público e privado. A seguir, foram definidos os múltiplos critérios através do processo de análise hierárquica (AHP). Utilizando Sistemas de Informações Geográficas (SIG) e álgebra de mapas, foi possível determinar o mapa de susceptibilidade em cinco classes e operacionalizar a plataforma de monitoramento, análise e alerta a riscos ambientais baseando-se nas áreas identificadas e nos dados dinâmicos meteorológicos e hidrológicos. Como resultado, foi gerado um banco de dados geográfico com abrangência regional (14.000 km²), que envolveu 7 critérios: declividade, distância das linhas de transmissão, densidade de drenagem, uso do solo, tipo do solo, densidade de fraturas e falhas, e precipitação. A distribuição das classes de susceptibilidade encontradas na região de estudo foram: muito baixa (1,5%), baixa (12%), média (34,9%), alta (45,3%) e muito alta (6,2%). Foi possível ainda, identificar diferentes movimentos de massa em áreas próximas à linhas de transmissão, quanto próximas aos outros elementos de risco, como moradias, estradas, bordas de reservatórios e torres de telecomunicações. A plataforma de monitoramento operacionalizada possibilitou o estabelecimento de análises dinâmicas sobre a ocorrência de eventos naturais extremos, através do envio de notificações e acesso WEB com o mapa das áreas afetadas. Assim, este estudo pode se tornar um instrumento de avaliação, acompanhamento e gerenciamento para a gestão pública e agências reguladoras do setor elétrico. / Most of the Brazilian electric sector enterprises do not present a systematic space-time evaluation of their structures to identify environmental vulnerabilities in the projects. Thus, this study aimed to analyze the susceptibility of mass movement in transmission lines, in the Serra da Mantiqueira region, subject to the effects of tropical rains and to operationalize a dynamic platform of analysis and alertness in the most critical areas. For this work, static and dynamic data were collected in the region from public and private sources. Next, the multiple criteria were defined through the hierarchical analysis process (AHP). Using Geographic Information Systems (GIS) and map algebra, it was possible to determine the susceptibility map in five classes and to operationalize the monitoring platform for monitoring, analysis and alert to environmental risks based on identified areas and dynamic meteorological and hydrological data. As a result, a geographic database with a regional coverage (14.000 km²) was generated, involving 7 criteria: slope, distance of transmission lines, drainage density, soil use, soil type, fracture and failure density, and precipitation. The distribution of susceptibility classes found in the study region were very low (1.5%), low (12%), average (34.9%), high (45.3%) and very high (6, 2%). It was also possible to identify different mass movements in areas close to the transmission lines, as well as to other risk elements such as dwellings, roads, reservoir borders and telecommunications towers. The operationalized monitoring platform allowed the establishment of dynamic analyzes on the occurrence of extreme natural events, by sending notifications and WEB access with the map of the affected areas. Thus, this study can become an instrument of evaluation, monitoring and management for the public management and regulatory agencies of the electric sector.
16

Evaluation Of Settlement Sites Beyond The Scope Of Natural Conditions And Hazards By Means Of Gis Based Mcda: Yesilirmak Catchment

Cintimur, Mehmet Bilgekagan 01 June 2010 (has links) (PDF)
Our country is a risky position in terms of natural disasters. In the long run, preferentially settlement areas were selected to ensure maximum benefits in terms of both economic and security aspects, other criteria is not taken account when selection of sites. The main purpose of this study is to examine and compare the properties of settlement location based on natural hazard and environmental constraints to be able to understand the interaction between the settlements and natural conditions at the regional scale of YeSilirmak Basin. A MCDA was set up with 10 different data layers in two data domains (environmental and natural hazards domains), are evaluated. The results of the MCDA scores are then transferred to settlement databases in order to evaluate the number of existing settlements in different environmental and natural hazard related suitability classes. It is found that almost 29% of YeSilirmak catchment is environmentally favorable for settlement, and in coherence with that 41% of all existing settlements are located in this zone, indicating a clear preference among the perception of environmentally better places to be settled in. On the other hand with respect to the natural hazards dataset, the locations of the settlements fail to create any preference, as 73,32% of the area is used by 73,50% of existing settlements, which indicates that the perception of natural hazards are low and do not effect settlement criteria, while the acceptable risk of community is high.
17

Vulnerabilidade ambiental aos processos erosivos lineares de parte dos municípios de Marabá Paulista-SP e Presidente Epitácio-SP / Environmental vulnerability to linear erosive processes in parts of Marabá Paulista-SP and Presidente Epitácio-SP

Fushimi, Melina [UNESP] 17 June 2016 (has links)
Submitted by MELINA FUSHIMI (melinafushimi@yahoo.com.br) on 2016-06-27T15:24:06Z No. of bitstreams: 1 TESE_FINAL_Melina Fushimi.pdf: 21884758 bytes, checksum: 0c1b17ce557210c1ae752004961a846d (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-06-28T17:14:34Z (GMT) No. of bitstreams: 1 fushimi_m_dr_prud.pdf: 21884758 bytes, checksum: 0c1b17ce557210c1ae752004961a846d (MD5) / Made available in DSpace on 2016-06-28T17:14:34Z (GMT). No. of bitstreams: 1 fushimi_m_dr_prud.pdf: 21884758 bytes, checksum: 0c1b17ce557210c1ae752004961a846d (MD5) Previous issue date: 2016-06-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / No atual momento histórico, diante das transformações aceleradas das paisagens, em que as dinâmicas da sociedade se interpenetram e, muitas vezes, se sobressaem às dinâmicas da natureza, a questão ambiental assume importância em vários campos do conhecimento, sobretudo, na Geografia. Em meio aos diversos trabalhos desenvolvidos no âmbito geográfico e ambiental, tem-se a erosão como um dos assuntos mais enfatizados. Neste contexto, o objetivo geral da tese foi analisar os principais elementos que influenciam na vulnerabilidade ambiental aos processos erosivos lineares (sulcos, ravinas e voçorocas) de parte dos municípios de Marabá Paulista-SP e Presidente Epitácio-SP. Sob a perspectiva teórico-metodológica do pensamento da complexidade, foram caracterizados os aspectos do relevo, declividade, solos, substrato rochoso, cobertura vegetal, curvatura da superfície e uso da terra, além da elaboração de documentos cartográficos em ambiente de Sistemas de Informação Geográfica, em especial, o mapa de vulnerabilidade ambiental aos processos erosivos lineares. Em virtude das possibilidades de integração dos dados e atribuição de pesos, o referido mapa foi realizado a partir da lógica fuzzy, especificamente, da Técnica do Processo Analítico Hierárquico (AHP), a qual proporcionou o mapeamento de maneira classificada: baixa (0.32%), média (65.15%), alta (34.45%) e muito alta vulnerabilidade (0.08%). A baixa vulnerabilidade está elencada às matas ciliares remanescentes. A média vulnerabilidade se localiza nos topos das colinas com declividades inferiores a 5%. O uso da terra predominante é a pastagem e os solos são, em sua maioria, desenvolvidos e arenosos. A alta vulnerabilidade está, principalmente, nas vertentes convexas e retilíneas, em que as inclinações podem alcançar 15%. A pastagem prevalece, todavia, verificou-se a expansão do cultivo de cana de açúcar e do solo exposto para seu consecutivo plantio. A muito alta vulnerabilidade apresenta-se nas vertentes côncavas, cuja curvatura favorece a convergência das águas pluviais e, portanto, o fluxo linear. Tal evento se intensifica perante às declividades acentuadas – superiores a 20% para a região. Combinado a estes atributos, sobre solos rasos tem-se o pastoreio intensivo do gado, o qual acelera a compactação do solo e acarreta a erosão, sendo uma das formas de degradação mais recorrente no Extremo Oeste Paulista. Assim, o presente estudo pode contribuir no sentido de orientar a implantação de medidas preventivas e corretivas de controle à erosão por intermédio do planejamento ambiental. / In the current historical moment, given the accelerated changes in landscapes, in which the dynamics of society interpenetrate and, often, exceed the dynamics of nature, the environmental issue assumes importance in several fields of knowledge, especially, Geography. Among the diverse assignments developed in geographical and environmental contexts, erosion is one of the most commonly emphasized subjects. Therefore, this thesis aimed to analyze the main elements that influence environmental vulnerability to linear erosive processes (rills, ravines and gullies) in parts of Marabá Paulista-SP and Presidente Epitácio-SP. From the theoretical-methodological perspective of thought complexity, the relief, slope plans, soils, bedrocks, vegetation, surface curvature and land use aspects were characterized, in addition to the elaboration of cartographic documents using the Geographic Information System, in particular, the map of environmental vulnerability to linear erosive processes. Due to the possibilities of integrating data and assigning weights, the map was performed based on fuzzy sets, specifically, the Analytical Hierarchy Process (AHP), which provided classified mapping: low (0.32%), medium (65.15%), high (34.45%) and very high vulnerability (0.08%). The low vulnerability is identified in the reminiscent cilliary forests. The medium vulnerability is located on the hilltops with slopes of less than 5%. The land use is predominantly for pasture and soils are for the most part developed and sandy. The high vulnerability is primarily the convex and rectilinear aspects, where the slopes can reach 15%. On the prevailing pasture, however, the expansion of the sugar cane crop was found and soil exposed to its successive planting. The very high vulnerability is present in the concave slopes, whose curvature favors the convergence of rainwater and thus, linear flow. This event is intensified towards the steep slopes – more than 20% of the region. Combined with these attributes, on shallow soils there is intensive grazing of livestock, which accelerates soil compaction and leads to erosion, one of the most recurrent means of degradation in the Far West of São Paulo. Thus, the present study may contribute to guiding the management of preventive and corrective measures to control erosion through environmental planning.
18

Investigation of New Forward Osmosis Draw Agents and Prioritization of Recent Developments of Draw Agents Using Multi-Criteria Decision Analysis

Yu, Jodie Wei 01 June 2020 (has links) (PDF)
Forward osmosis (FO) is an emerging technology for water treatment due to their ability to draw freshwater using an osmotic pressure gradient across a semi-permeable membrane. However, the lack of draw agents that could both produce reasonable flux and be separated from the draw solution at a low cost stand in the way of widespread implementation. This study had two objectives: evaluate the performance of three materials — peptone, carboxymethyl cellulose (CMC), and magnetite nanoparticles (Fe3O4 NPs) — as potential draw agents, and to use multi-criteria decision matrices to systematically prioritize known draw agents from literature for research investigation. Peptone showed water flux and reverse solute flux values comparable to other organic draw agents. CMC’s high viscosity made it impractical to use and is not recommended as a draw agent. Fe3O4 NPs showed average low fluxes (e.g., 2.14 LMH) but discrete occurrences of high flux values (e.g., 14 LMH) were observed during FO tests. This result indicates that these nanoparticles have potential as draw agents but further work is needed to optimize the characteristics of the nanoparticle suspension. Separation of the nanoparticles from the product water using coagulation was shown to be theoretically possible if only electrostatic and van der Waals forces are taken into account, not steric repulsion. If coagulation is to be considered for separation, research efforts on development of nanoparticle suspensions as FO draw agents should focus on development of electrostatically stabilized nanoparticles. A combination of Fe3O4 NP and peptone showed a higher flux than Fe3O4 NPs alone, but did not produce additive or synergistic flux. This warrants further research to investigate more combinations of draw agents to achieve higher flux than that obtained by individual draw agents. Potential draw agents were prioritized by conducting a literature review of draw agents, extracting data on evaluation criteria for draw agents developed over the past five years, using these data to rank the draw agents using the Analytical Hierarchy Process (AHP) and Technique for Order of Preference by Similarity to Ideal Solutions (TOPSIS). The evaluation criteria used in the ranking matrices were water flux, reverse solute flux, replenishment cost, regeneration cost, and regeneration efficacy. The results showed that the top five ranked draw agents were P-2SO3-2Na, TPHMP-Na, PEI-600P-Na, NaCl, and NH4-CO2. The impact of the assumption made during the multi-criteria decision analysis process was evaluated through sensitivity analyses altering criterion weighting and including more criteria. This ranking system provided recommendations for future research and development on draw agents by highlighting research gaps.
19

Generator Maintenance Scheduling Models in Power Systems. Integrated Cost Models for Generator Maintenance Strategy under Market Environment.

Al-Arfaj, Khalid A. January 2009 (has links)
Change from a regulated to deregulated structure means that, the centralized maintenance system is not valid any more. In the surveyed published literature, there is not a single model which incorporates all maintenance cost components to analyze the effect of different maintenance strategies for generator companies (GENCOs). The work enclosed in this thesis demonstrates that there is a considerable requirement for accurately modelling cost components of the maintenance model, to be used in maintenance scheduling for deregulated power system, in order to attain a superior schedule with major financial and operational impact. This research investigates and models most cost factors that affect the maintenance activities of the deregulated GENCOs, and demonstrates the utilization of the developed cost models in maintenance scheduling. It also presents the data gathering process for the developed maintenance cost model. A generator maintenance scheduling model that considers direct and indirect maintenance costs, opportunity costs (i.e. loss of customer goodwill), effective maintenance strategies, failures, and interruptions is developed. A Genetic Algorithm (GA) based approach is employed to achieve maintenance schedules to various generators maintenance scenarios. An Analytical Hierarchy Process (AHP) approach is proposed for modelling customer goodwill. The maintenance model was redeveloped under the Reliability Centred Maintenance (RCM) strategy to analyze the effect of a maintenance strategy on maintenance costs. Case studies are presented to demonstrate the utilisation of the developed models.The investigation shows that the market prices, opportunity costs and maintenance strategy have an effect on the final maintenance schedule. The research demonstrates that the cost components are critical factors to achieve an effective maintenance schedule, and they must be considered and carefully modelled in order to reflect more realistic situation for maintenance scheduling of generator units in deregulation environment.
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Identifiering av lämpliga platser för bostadsexploatering med hänsyn till översvämningsrisk

Nordlander, Hanna, Holm, Mie January 2022 (has links)
Klimatförändringarna och den globala uppvärmningen är ett faktum som kan leda till kraftigare nederbördstillfällen samt öka risken för bland annat översvämningar. Översvämningsrelaterade katastrofer har under de senaste 20 åren ökat och översvämningsrelaterade händelser står för 44 procent av världens naturkatastrofer. Samtidigt ökar tillväxten av många städer och samhällen vilket sätter större krav på beslutsfattare och kommuner att välja lämpliga platser för exploatering. Syftet med studien är att undersöka hur en GIS-baserad multikriterieanalys kan användas för att identifiera översvämningsrisker samt hur karteringen över översvämningsrisker vidare kan användas för att identifiera lämpliga platser för bostadsexploatering. Studien utfördes genom att intervjua översvämningsexperter och samhällsplanerare, samt genom att använda geografiska informationssystems (GIS)-baserade metoder såsom Multikriterieanalys (MKA), Analytisk hieratisk process (AHP) och känslighetsanalys. Intervjuerna gav värdefulla synpunkter på kriterier, rangordning och viktning. Resultaten av översvmningsriskkarteringen visar de områden som har mycket hög till mycket låg risk att exponeras för en översvämning. För att identifiera lämpliga platser för bostadsutveckling användes översvämningsriskkarteringen som ett kriterium tillsammans med andra viktiga komponenter såsom fysiska och sociala faktorer. Resultaten visar att den lämpligaste platsen är lokaliserad i den sydvästra delen av Näringen och har en storlek på 25 737 kvadratmeter (kvm). Den känslighetsanalys som utfördes i studien, genom att ändra rangordningen på kategorierna (översvämningsrisk, fysiska- och sociala faktorer), visade det att den största förändringen skedde när de sociala faktorerna fick en hög rangordning och vikt. Diskussionen och slutsatsen visar hur bland annat valet av kriterier och intervjupersoner kan påverka resultatet och att det finns många osäkerheter med att använda MKA. Resultatet av en MKA bör därför utvärderas om det ska vara möjligt att avgöra om bostäder kan exploateras på Näringen. / Climate change and global warming are some causes that can lead to heavier precipitation and increased risk of floods. Flood-related disasters have increased over the past 20 years and 44 percent of the world's natural disasters are due to flood-related events. At the same time, the growth is increasing in many of the world's cities and communities, which places greater demands on decision-makers and municipalities to choose suitable places for exploitation. The purpose of the study is to investigate how a GIS-based multi-criteria analysis can be used to identify flood risks and how the mapping of flood risks can be used further to identify suitable sites for housing development. The study was conducted by interviewing flood experts and urban planners and implementing Geographic Information Systems (GIS)-based method such as Multi-criteria Analysis (MCA), Analytical Hierarchy Process (AHP) and Sensitivity Analysis to produce the results. The respondents provided valuable views on the criteria, ranking and weighting of criteria. The results of the flood hazard map show the areas that are at high and low risk of being flooded. In finding suitable sites for housing development, the flood hazard map was used as an input together with other important components such physical and social factors. The results show that the most suitable place is in the southwestern part of Näringen, which has a size of 25 737 m2. In the sensitivity analysis that was performed where ranking of the categories was changed (flood risk, physical and social factors), it showed that the biggest change took place when the social factors received high ranking and weight. The discussion and conclusion show how the choice of criteria, weighting and interviews can affect the results and the many uncertainties with using MCA. The results of an MCA should therefore be evaluated if it is to be possible to decide whether housing can be exploited on Näringen.

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