Increasing energy consumption is a result of the rapid growth in cellular communication technologies and a massive increase in the number of mobile terminals (MTs) and communication sites. In cellular communication networks, energy efficiency (EE) and spectral efficiency (SE) are two of the most important criteria employed to evaluate the performance of networks. A compromise between these two conflicting criteria is therefore required, in order to achieve the best cellular network performance. Fractional frequency reuse (FFR), classed as either strict FFR or soft frequency reuse (SFR), is an intercell interference coordination (ICIC) technique applied to manage interference when more spectrum is used, and to enhance the EE. A conventional cellular model's downlink is designed as a reference in the presence of inter-cell interference (ICI) and a general fading environment. Energy-efficient cellular models,such as cell zooming, cooperative BSs and relaying models are designed, analysed and compared with the reference model, in order to reduce network energy consumption without degrading the SE. New mathematical models are derived herein to design a distributed antenna system (DAS), in order to enhance the system's EE and SE. DAS is designed in the presence of ICI and composite fading and shadowing with FFR. A coordinate multi-point (CoMP) technique is applied, using maximum ratio transmission (MRT) to serve the mobile terminal (MT), with all distributed antenna elements (DAEs), transmit antenna selection (TAS) being applied to select the best DAE and general selection combining (GSC) being applied to select more than one DAE. Furthermore, a Cloud radio access network (C-RAN) is designed and analysed with two different schemes, using the high-power node (HPN) and a remote radio head (RRH), in order to improve the EE and SE of the system. Finally, a trade-off between the two conflicting criteria, EE and SE, is handled carefully in this thesis, in order to ensure a green cellular communication network.

Made available in DSpace on 2014-07-29T15:03:38Z (GMT). No. of bitstreams: 1 dissertacao ricardo.pdf: 2894239 bytes, checksum: c7ade6470d36ad62bc264e4ee243965b (MD5) Previous issue date: 2007-10-17 / The increasing demand for aggregate for uses in engineering stimulated the search for alternative materials. In this way, the civil construction potentially started to be a great consumer of residues from other industries, becoming a great recycle plant. The use of by-product, brings great environmental benefits in relation to the degradation of the environment, as for example, less settlement of residues in earth fill, the reduction of extraction of natural resources, and the exploration of aggregate ores. Steel plants from around the world have a commom problem, that is what to do with all the steel slags generated as a by-product from the steel refining in electric steel plants or oxygen steel plants. There are two points of these process where slags can be generated: the first comes from the electric or oxygen furnace itself (called oxidizing refining) and the second is the laddle metallurgy slag (reduction refining slag), which is the last stage of the steel production. This aims to demonstrate related studies to the use of steel slags (EAF slags) in electric steel plants as coarse aggregate. Expansibility of the steel slag tests had been carried through, compressive strength, tensile strength for diametrical compression, related modulus of deformation and durability tests, such as: intensity of corrosion, potential of corrosion, ohmic resistivity and depth of carbonation. After this, it was observed the similarity of the results between the concrete made with steel slag and the concrete made with conventional aggregates, natural aggregate known as mica schist. It was observed improvements in the properties of the concrete with steel slag, such as: increase in its strength (compressive / tensile) and increase of the modulus of deformation. Concerning the durability, it was noted, in a general way, that the substitution of the aggregates, conventional for siderurgical, has not influenced in the performance of the concrete. / A crescente demanda por agregados para usos em engenharia estimulou a procura por materiais alternativos. Desta forma, a construção civil passou a ser potencialmente uma grande consumidora de resíduos provenientes de outras indústrias, tornando-se uma grande usina recicladora. A utilização de subprodutos traz benefícios ambientais bastante expressivos em relação à degradação do meio ambiente, como por exemplo, a menor deposição de resíduos em aterros, a diminuição da extração predatória de recursos naturais e a exploração de jazidas de agregados. As siderúrgicas, em nível mundial, vêm enfrentando um problema comum, que consiste no que fazer para que a totalidade da escória gerada no refino do aço em aciarias elétricas ou a oxigênio tenha uma solução de aproveitamento melhor do que vem sendo feito atualmente. Na fabricação do aço as escórias são geradas em duas etapas: a primeira provém do chamado refino oxidante (forno elétrico a arco ou convertedor à oxigênio) e a segunda do refino redutor em processos de metalurgia na panela (forno-panela). Este trabalho tem como objetivo específico demonstrar, por meio de estudos, a potencialidade do uso das escórias de aciaria elétrica (escórias FEA) como agregado graúdo. Foram realizados ensaios de expansibilidade, resistência à compressão, à tração por compressão diametral, módulo de deformação e ensaios relacionados à durabilidade, tais como: intensidade de corrente de corrosão, potencial de corrosão, resistência ôhmica e profundidade de carbonatação. Após o estudo realizado observou-se a semelhança dos resultados dos concretos confeccionados com escória de aciaria elétrica com os concretos confeccionados com agregados convencionais, no caso o micaxisto. Podem-se constatar melhorias nas propriedades dos concretos produzidos com escória, tais como: aumento em suas resistências (compressão / tração) e aumento do módulo de deformação. No que diz respeito à durabilidade verificou-se, de uma maneira geral, que a substituição dos agregados, convencional por siderúrgico, não influenciaram no desempenho dos concretos.

Made available in DSpace on 2015-09-25T12:18:45Z (GMT). No. of bitstreams: 1 IsraelNunesHenrique.pdf: 1394330 bytes, checksum: 72328b064472d745a8632e5b12e4b28c (MD5) Previous issue date: 2006-02-20 / The treated domestic sewer when available for the agricultural activities provides economy of water of good quality and chemical fertilizers and it motivates to the agricultural activities. In the semi-arid area of Brazil the reuse of water can be an alternative for the coexistence with the shortage of the hydric resources. In this context, the rural workers of the Municipal district of Lagoa Seca, PB, that produce vegetables during all year as source of revenue happening of the family agriculture. Several researches were already accomplished with the purpose of developing technologies of treatment of sewers that produces effluents with smaller risks of transmission of diseases, but guaranteeing appropriate concentrations of nutrients to the irrigated cultures. The present study had as objective to evaluate the sanitary aspects and nutricionais of the effluents of treated sewers in a system formed by a reactor UASB followed by polishing pond. The use of those effluents was also verified in the fertigation of bell pepper (Capsicum annuum L.). Compared with treatments of the soil using mineral and organic manuring, the planting of the bell pepper obeyed the statistical planning of blocks random, with 5 treatments and 4 repetitions. During the experimental period weekly analyses of the effluents were accomplished and of the culture of bell pepper. The pos-treatment of the sewer in the polishing pond produced effluent with sanitary quality inside of the values recommended by the World Organization of Health (OMS, 1989) for irrigation of vegetables consumed raw. The bell pepper irrigated with effluent of the reactor UASB didn't present significant difference of productivity (at the level of 5% of probability for the test Tukey), when compared to the application of mineral and organic manuring. / O esgoto doméstico tratado quando disponibilizado para as atividades agrícolas proporciona economia de água de boa qualidade e fertilizantes químicos e incentiva às atividades agrícolas. Na região semi-árida do Brasil o reúso de água poderá ser uma alternativa para a convivência com a escassez dos recursos hídricos. Neste contexto, estão inseridos os trabalhadores rurais do Município de Lagoa Seca, PB, que produzem hortaliças durante todo ano como fonte de renda advindo da agricultura familiar. Diversas pesquisas já foram realizadas com a finalidade de desenvolver tecnologias de tratamento de esgotos que produza efluentes com menores riscos de transmissão de doenças, mas garantindo concentrações adequadas de nutrientes às culturas irrigadas. O presente estudo teve como objetivo avaliar os aspectos sanitários e nutricionais dos efluentes de esgotos tratados em um sistema formado por um reator UASB seguido de lagoa de polimento. Também foi verificada a utilização desses efluentes na fertirrigação de pimentão (Capsicum annuum L.). Comparada com tratamentos do solo utilizando adubação mineral e orgânica, o plantio do pimentão obedeceu ao delineamento estatístico de blocos ao acaso, com 5 tratamentos e 4 repetições. Durante o período experimental foram realizadas análises semanais dos efluentes e da cultura de pimentão. O pós-tratamento do esgoto na lagoa de polimento produziu efluente com qualidade sanitária dentro dos valores recomendados pela Organização Mundial de Saúde (OMS, 1989) para irrigação de vegetais consumidos crus. O pimentão irrigado com efluente do reator UASB não apresentou diferença significativa de produtividade (ao nível de 5% de probabilidade pelo teste Tukey), quando comparado à aplicação de adubação mineral e orgânica.

A indústria de desenvolvimento de software está em constante evolução e em busca de novos desafios, como por exemplo: novas tecnologias, linguagens de programação e estratégias para aumentar a produtividade no desenvolvimento. Com o passar do tempo, essa evolução desejada tem se concretizado, em especial com o surgimento de conceitos como Service Oriented Architecture (SOA) e Model-Driven Development (MDD). Nesse contexto, ganha importância a reutilização de software, por exemplo por meio do uso de serviços que facilitam a interoperabilidade entre diferentes sistemas. Ambientes de desenvolvimento de software, em especial ambientes de reúso de software, poderiam se adequar à arquitetura SOA para facilitar a disponibilização de serviços a outros ambientes, promovendo sua integração e aumentando a possibilidade de reúso. Após um levantamento bibliográfico sobre ambientes integrados de reúso que utilizassem serviços para permitir o compartilhamento de recursos, percebeu-se que os trabalhos nessa direção são poucos. Ao mesmo tempo, observou-se que para integração de sistemas por meio de serviços é necessário criar camadas de acesso às entidades dos sistemas que compartilharão informações. A implementação desses serviços de forma manual é repetitiva e sujeita a erros, principalmente por programadores que não estão familiarizados com SOA. Por outro lado, diagramas de classes em UML (Unified Modeling Language) são de amplo conhecimento por parte de desenvolvedores e estão em um nível de abstração que é suficientemente detalhado para permitir a derivação de serviços de acesso às suas classes. Desta forma, para atender uma demanda crescente de sistemas que precisam oferecer serviços para possibilitar sua integração com outros sistemas, este mestrado tem por objetivo promover a geração automatizada de código de serviços por meio de transformações de modelo para texto, em que o modelo de entrada é um diagrama de classes derivado da UML e os serviços gerados cobrem operações básicas do tipo CRUD. O gerador resultante foi validado por meio de duas provas de conceito e mostrou-se adequado para cumprir os objetivos estabelecidos, visto que o desenvolvedor trabalha com um modelo em alto nível de abstração, não precisando conhecer os detalhes inerentes à implementação dos serviços. / The software development industry is constantly evolving and looking for challenges, such as: new technologies, programming languages and strategies to increase developers productivity. During the course of time, this required evolution has been concretized, especially with the emergency of concepts such as Service Oriented Architecture (SOA) and Model-Driven Development (MDD). In this context, software reuse gains importance, for example through the use of services that ease the interoperability of different systems. Software development environments, in special reuse environments, could be adapted to the SOA architecture to ease the availability of services to other environments, thus promoting its integration and possibility of reuse. After a literature review about integrated reuse environments that use services to allow resources sharing, it has been observed that there are only a few works in this direction. At the same time, it was observed that for system integration through services it is required to create an access layer for the system entities that share information. The manual implementation of these services is repetitive and error prone, especially for programmers who are not familiar with SOA. On the other hand, UML (Unified Modeling Language) class diagrams are widely known by developers and are at a level of abstraction that is sufficiently detailed to allow the derivation of access services to their classes. Thus, to meet a growing demand for systems that need to provide services to enable its integration with other systems, this masters dissertation aims to promote the automated generation of service code through transformations from model to text, where the input model is a class diagram derived from UML, and the generated services cover the basic CRUD operations. The resulting generator has been validated through two proofs of concepts and was adequate to meet the stated objectives, as the developer works with a model in a high abstraction level, and does not need to know the details related with the service implementation.

Thesis (MSc. (Geography and Environmental Science)) -- University of Limpopo, 2015. / Fresh water is a finite and vulnerable resource, essential to sustain life, development and the environment. Growth in population and economic activities have contributed to water scarcity, which is a frequent challenge in rural and township communities in South Africa. This study aimed at investigating onsite greywater reuse as a water conservation method in Lepelle-Nkumpi local municipality, Limpopo province. The study described the socio-economic characteristics, assessed the accessibility and availability of water supply, and ascertained the coping mechanisms for water scarcity as well as the perceptions and reuse of greywater. Four percent respondents each were selected from two settlements, namely, Mashite village and Lebowakgomo township (Zone F). Mashite village had a population size of 5314 people (1231 households) and Lebowakgomo Zone F had 5903 people and (1924 households). A systematic random sampling method was used to select the required households from the two settlements. Both open and close ended questionnaires were used. A Geographical Positioning System was also used to collect the absolute location of available taps in the study area. Data collected were analysed using SPSS version-22 and Arc GIS 10.1. The study found out that the socio-economic characteristics of importance on onsite greywater reuse included highest qualification, household size and employment status, but they varied in these two areas. In Mashite village the majority of the respondents went to secondary school (59%) as compared to Lebowakgomo Zone F where the majority (72%) attained tertiary qualification. Household size mean in Mashite is 6.18 as compared to Lebowakgomo Zone F (2.77). Sixty four percent of respondents in Mashite village were unemployed, whereas in Lebowakgomo 69% were employed. Water usage in the two areas differed; in Mashite village where they use less water (250 to 840 litres) as compared to Lebowakgomo Zone F, where more water is used (5900 to 8001 litres). In Mashite village, 87% of the respondents could not access water due to inaccessibility of taps and unavailability of water as compared to Lebowakgomo zone F (100%). It was also found that the Mashite community sometimes go for a period of two to three months without tap water whereas in Lebowakgomo water was comparatively regular. As a result both communities resorted to rainwater harvesting and greywater reuse. Seventy six percent (76%) of respondents in Mashite village and 30% of the respondents in ii Lebowakgomo Zone F harvested rainwater as a coping mechanism of water scarcity. Perceptions of greywater reuse were higher (76%) in Lebowakgomo Zone F compared to Mashite village (49%). A higher percentage of Mashite village respondents (98%) reuse greywater compared to Lebowakgomo Zone F respondents (59%). Both areas use greywater as water conservation method. These results reinforce the potential of domestic greywater reuse as an alternative for freshwater requirement. Greywater reuse as a water conservation method especially in villages can be used to alleviate the extent of water scarcity. / National Research Foundation (NRF)

<p>In the context of climate change, increasing demands for freshwater make it necessary to manage our water resources in a sustainable way and find innovative ways to extend their life. An integrated water management approach needs to consider anthropogenic water use and reuse which represent major components of the current water cycle. In particular, unplanned, or de facto, indirect water reuse occurs in most of the U.S. river systems; however, there is little real-time documentation of it. Despite the fact that there are national and state agencies that systematically collect data on water withdrawals and wastewater discharges, their databases are organized and managed in a way that limits the ability to combine reported water data to perform large scale analysis about water use and indirect reuse. To better document these issues and to demonstrate the utility of such an analysis, I studied the Wabash River Watershed located in the U.S. Midwest. Existing data for freshwater extraction, use, discharge, and river streamflow were collected, curated and reorganized in order to characterize the water use and reuse within the basin. Indirect water reuse was estimated by comparing treated wastewater discharges with stream flows at selected points within the watershed. Results show that during the low flow months of July-October 2007, wastewater discharges into the Wabash River basin contributed 82 to 121% of the stream flow, demonstrating that the level of water use and unplanned reuse is significant. These results suggest that intentional water reuse for consumptive purposes such as landscape or agricultural irrigation could have substantial ecological impacts by diminishing stream flow during vulnerable low flow periods. This research also completed a time series watershed-scale analysis of water use and unplanned indirect reuse for the Wabash River Watershed from 2009 to 2017. Results document the occurrence of indirect water reuse over time, ranging from 3% to 134% in a water-rich area of the U.S. The time series analysis shows that reported data effectively describe the water use trends through nine years, clearly reflecting both anthropogenic and natural events in the watershed, such as the retirement of thermoelectric power plants, and the occurrence of an extreme drought in 2012. Results demonstrate the feasibility and significance of using available water datasets to perform large scale water use analysis, describe limitations encountered in the process, and highlight areas for improvement in water data management.</p>

2018 startade några boende i Björkhagen söder om Stockholm föreningen ”Björkhagens Hjärta”. De saknade gemensamma lokaler och ville arbeta för ett kulturhus i den nedlagda och rivningshotade panncentralen, fastigheten ”Åskvädret 2” på Halmstadsvägen/ Hässleholmvägen. I en slagning på panncentraler i Stockholm visade det sig att det finns många panncentraler i området som befinner sig i en liknande situation. I och med byte till fjärrvärme uttjänade byggnaderna på 1960- och 70-talen sitt syfte, och blev stående tomma eller uthyrda till verksamheter på korta och tillfälliga kontrakt. Då marken där dessa panncentraler ligger blivit dyrare och kommunen behöver mark till bostäder, finns ofta ett rivningshot kopplat till dessa byggnader. I mitt masterarbete undersöker jag specifikt panncentralen Åskvädret 2 som möjlig gemensam plats för de boende i området Björkhagen men spekulerar även vidare om strategier jag testar skulle kunna användas för att utveckla och skapa gemensamma rum i andra panncentraler. Med rummens storskaliga och industriella karaktär, ofta placerade centralt i ett bostadsområde finns en potential som jag blev nyfiken på att undersöka. Vad händer om man utgår från det befintliga och anpassar verksamheter och arkitektoniska tillägg utifrån det? Genom att med små medel förändra och förvalta det material som redan finns och har funnits på platsen, vill projektet inkludera både social och ekologisk hållbarhet med mål att återaktivera stadens rum för demokrati. Idag ser vi en stadsplanering som mest fokuserar på att maximera antal kvadratmeter boyta. Vi behöver fler bostäder, men var finns platserna för umgänge, dans, lek och debatt? / In 2018, residents in Björkhagen, south of Stockholm, started the association “Björkhagens Hjärta”. The lack of a communal space spurred their desire to develop a community center in a disused abandoned and demolition-threatened local heating plant, the property “Åskvädret 2”. In a Google-search for local heating plants in Stockholm, it became apparent that many others in the area are in a similar situation. These buildings served their purpose in the 1960s and 70s, after the transition to district heating, however, they were left empty or rented out to businesses on short and temporary contracts. As the land where these plants are located has become more valuable and municipalities need land for housing, there is often a threat of demolition linked to these buildings. In my master's thesis I investigate specifically the heating plant Åskvädret 2 as a possible community centre for residents in the Björkhagen area, additionally I speculate further whether the strategies I test could be used to develop and create similar spaces in other disused heating plats. The large scale and industrial character of these spaces, often located centrally in residential areas, was recognized as a potential that I became curious to explore. What happens if we start off with something that already exsist and adapt activities and architectural additions based on that? By using minimal funds to change and manage the material that already exists and has existed on the site, the project wants to include both social and ecological sustainability with the goal of reactivating the city's space for democracy. Today we see an urban planning that focuses mostly on maximizing the number of square meters of living space. We need more housing, but where are the places for socializing, dance, play and debate?

No description available.

Thesis (M. Sc. (Geography)) -- University of Limpopo, 2021 / Great interests in the geographical dimensions of poverty, food security, natural resources such as land and water, and livelihoods have been motivated by global efforts of reducing poverty and food insecurity, as part of the millennium development agenda. The achievement of household food security is a major concern facing the world at large, including South Africa due to the lack of land and water resources availability and accessibility. The study aimed at evaluating the potential reuse of greywater to improve household food security in two villages of Fetakgomo Local Municipality. The objectives of the study were to establish background characteristics, determine household food accessibility and availability, assess the reuse of greywater in relation to home gardening activities, ascertain the perceptions on greywater reuse and lastly to determine the household food security status of the households. The study adapted a mixed research approach and a 4% sample size was used. Ninety five and seventy eight households were randomly selected for Ga-Seroka and Ga-Nkwana villages, respectively. Data was collected using a structured questionnaire and the results were analysed using Statistical Package for the Social Sciences (SPSS) version-23 software. General Household Survey (GHS) in combination with Household Food Insecurity Access Scale (HFIAS) were used to assess household food security status of the two villages. The key results revealed that background characteristics of importance on greywater reuse include household size, educational level and employment status even though they varied in these two areas. Accessibility and availability of food was found to be more of a challenge in Ga-Seroka village than in Ga-Nkwana village. Respondents from Ga-Seroka village reused their greywater more as they drained it directly into their gardens. According to the HFIAS classification measure, 85% and 73% of households were categorised as least food insecure, 15% and 26% as medium food insecure and 0% and 1% as severely food insecure in Ga-Nkwana and Ga-Seroka villages respectively. Ga-Seroka village respondents preferred to reuse their greywater more often as compared to respondents in Ga-Nkwana village and were not reluctant to use it in their gardens. In conclusion, reuse of greywater has a potential to improve household food security. There is a need for the government to subsidize the households with incentives such as quality seeds and fertilizers in order to enhance their productivity and thus improving their household food security. Keywords: Food security, availability, accessibility, land, water, Fetakgomo Local Municipality, greywater reuse. / National Research Foundation (NRF)

This study determined effects of addition of secondarily treated municipal wastewater effluent on an urban reservoir receiving system. Monthly water quality monitoring of the receiving reservoir and the wastewater, chemical analysis, and monthly laboratory algal assays, were conducted from September 1984 to September 1985. The nutrient status and algal growth potential of the receiving water and the wastewater confirmed the biostimulatory properties of the wastewater. Field validation studies were conducted using limnocorrals. Tertiary treatment of the wastewater using chemical coagulation precipitation with alum and ferric chloride reduced phosphorus concentrations in the wastewater to levels which supported significantly less algal biomass than untreated wastewater. These studies indicate ferric chloride to be a more effective coagulant for phosphorous removal alum.