The steady and aggressive downscaling of the physical dimensions of the conventional metal-oxide-semiconductor field-effect-transistor (MOSFET) has been the main driving force for the IC industry and information technology over the past decades. As the device dimensions approach the fundamental limits, novel double/trigate device architecture such as FinFET is needed to guarantee the ultimate downscaling. Furthermore, Schottky barrier source/drain technology presents a promising solution to reducing the parasitic source/drain resistance in the FinFET. The ultimate goal of this thesis is to integrate Schottky barrier source/drain in FinFETs, with an emphasis on process development and integration towards competitive devices. First, a robust sidewall transfer lithography (STL) technology is developed for mass fabrication of Si-nanowires in a controllable manner. A scalable self-aligned silicide (SALICIDE) process for Pt-silicides is also developed. Directly accessible and uniform NWs of Ni- and Pt-silicides are routinely fabricated by combining STL and SALICIDE. The silicide NWs are characterized by resistivity values comparable to those of their thin–film counterparts. Second, a systematic experimental study is performed for dopant segregation (DS) at the PtSi/Si and NiSi/Si interfaces in order to modulate the effective SBHs needed for competitive FinFETs. Two complementary schemes SIDS (silicidation induced dopant segregation) and SADS (silicide as diffusion source) are compared, and both yield substantial SBH modifications for both polarities of Schottky diodes (i.e. φbn and φbp). Third, Schottky barrier source/drain MOSFETs are fabricated in UTB-SOI. With PtSi that is usually used as the Schottky barrier source/drain for p-channel SB-MOSFETs, DS with appropriate dopants leads to excellent performance for both types of SBMOSFETs. However, a large variation in position of the PtSi/Si interface with reference to the gate edge (i.e., underlap) along the gate width is evidenced by TEM. Finally, integration of PtSi NWs in FinFETs is carried out by combining the STL technology, the Pt-SALICIDE process and the DS technology, all developed during the course of this thesis work. The performance of the p-channel FinFETs is improved by DS with B, confirming the SB-FinFET concept despite device performance fluctuations mostly likely due to the presence of the PtSi-to-gate underlap. / QC 20100923

Växande städer leder till att naturmark omvandlas till stadsmiljöer. Det skapar mer hårdgjorda ytor och därmed ökade volymer dagvatten som behöver hanteras. Modellering av dagvattennätet används ofta för att bedöma kapaciteten och risk för översvämningar. Avrinningsområdets storlek är en avgörande parameter för att bedöma hur mycket vatten som kommer till en viss ledning. Traditionellt har automatisk bestämning av avrinningsområden gjorts enbart utifrån topografin. I områden med dagvattennät styr däremot ledningarnas sträckning i första hand hur vattnet rinner, och de följer inte nödvändigtvis terrängen. ArcHydro Tools, som är ett tilläggsprogram till ArcMap, har utvecklats för att beräkna topografiska avrinningsområden. Genom att programmera en tilläggsfunktion i Python har processen i ArcHydro Tools anpassats för att kunna ta hänsyn till dagvattennätet. Dagvattennätet approximerades som vattendrag. Tryckledningar och tunnlar tillåter inte något inflöde av vatten. Därför beskrevs dessa som ändpunkter i ledningsnätet, varifrån vattnet inte rann vidare. Funktionen som skapades i det här examensarbetet tillät att vattnet stannade i dessa punkter, till skillnad från i den ursprungliga metoden. Den utgick istället från att vattnet rann till kanten av det undersökta området, vilket i de här fallen skulle ha resulterat i felaktigt avgränsade avrinningsområden. Tilläggsfunktionen anpassades för att användas som övriga funktioner i ArcMap och testades på data över Lidingö stad. Resultatet visade att det var möjligt att utnyttja topografiskt baserade metoder för bestämning av avrinningsområden så att avgränsningen istället skedde med utgångspunkt i dagvattennätet. Det är ett steg mot att effektivisera processen för bestämning av avrinningsområden för användning vid hydrologisk modellering av dagvattennätet. Behovet av manuell bearbetning minskas. Ett försök att i ArcMap implementera en funktion för efterbehandling av avrinningsområden gjordes också. Funktionen letar upp avrinningsområden som bedöms som för små och lägger ihop dem med ett närliggande område. Avrinningsområden som beräknats med den modifierade metoden har senare använts vid modellering av dagvattennätet i Molkom, Värmland. / Growing populations result in expanding cities. An increase in the amount of impervious surfaces in the area will follow and thereby generate more storm water. The capacity of the drainage system can be evaluated using hydraulic modelling. The model highly depends on the catchment areas, which will determine the water volume each pipe section receive. Watershed delineation is usually done based on the topography. However, if a storm water drainage system is present, it may route the water in a different direction than the slope indicates. ArcHydro Tools is an extension to ArcMap and is commonly used to delineate catchment areas. The method heavily relies on topography during this process. A function has been developed during the course of this project to allow for the drainage system to be the primary source of information for watershed delineation. This function made sure that outlets in the model were to be evaluated as such, even if they happen to be located in the middle of the area of interest. The water is therefore not necessarily routed to the edge of the elevation model, but can be allowed to stay at the appropriate position. In order to do this, the drainage system was represented as a stream network. The new method was applied to test data supplied by Lidingö city, Stockholm, Sweden, and included elevation data and information about the drainage system. The result implies that it is indeed possible to use the drainage system as a base for delineation of catchment areas. A more efficient method of calculating catchment areas will reduce the required amount of manual processing, thereby saving time and resources. Another function, for finishing up the resulting catchment areas, is proposed but not fully implemented. The whole process was used to delineate catchment areas for Molkom, County of Värmland, Sweden. The resulting watersheds were later successfully used for modelling the storm water drains in the area.

This thesis describes the design, fabrication and characterization of AlGaN/GaN Heterostructure Field E ect Transistors (HFETs) grown by a Metal Organic Chemical Vapor Deposition (MOCVD) on sapphire substrates. The objective of this research is to develop AlGaN/GaN power devices with high breakdown voltage (greater than 1 kV) and low turn-on resistance. Various characteristics such as current drive (Idss), transconductance (gm) and threshold voltage (Vth) have also been measured and the results have been discussed. Two major challenges with the development of high breakdown voltage AlGaN/GaN HFETs in the past have been high material defect density and non-optimized fabrication technologies which gives rise to bu er leakage and surface leakage, respectively. In this thesis, mesa isolation, ohmic and gate metal contacts, and passivation techniques, have been discussed to improve the performance of these power transistors in terms of low contact resistance and low gate leakage. The relationship between breakdown voltage and Rds(ON)A with respect to the gate-drain length (Lgd) is also discussed. First, unit cell devices were designed (two-fingered cells with Wg = 100, 300, 400 m) and characterized, and then they were extended to form large area devices (upto Wg = 40 mm). The design goals were classied into three parts: - High Breakdown Voltage: This was achieved by designing devices with variations in Lgd, - Low turn-on resistance: This was achieved by optimizing the annealing temperatures as well as incorporating additional thick metal pads, as well as optimizing the passivation etch recipe, - Low Gate Leakage: The gate leakage was reduced signicantly by using a gate metal with a larger barrier height. All devices with Lgd larger than 10 m exhibited excellent breakdown voltage characteristics of over 800 V, and it progressed as the Lgd increased. The turn-on resistance was also reduced signicantly below 20 m-cm2, for devices with Lgd = 15, 25, and 20 m. The gate leakage was measured for all devices upto 200 V, and was in the range of 10-100 nA, which is one of the best values reported for multi-ngered devices with Lgd in the range of 2.4-5 mm. Some of the key challenges faced in fabrication were determining a better gate metal layer to reduce gate leakage, optimizing the passivation via etch recipe, and reducing surface leakage.

This research project incorporates the theory that global integration is shaped by national, regional and local dynamics South Africa's integration into the globa arena is affected by its attempts to enhance empowerment, restructure the labour market, remove discrimination and increase participation. In this case study, the factors that encourage the retention of skilled IT professionals and graduates in KZN were investigated, to explore the reasons why despite opportunities for global advancement in the IT sector, skilled Individuals choose to remain in localities that are assumed to be " skill-exporting" areas This study has revealed that innovation is the key 10 a dynamic and successful IT sector in KZN. The formation of technology-intensive organizations is vital in order to develop local capabilities and 10 compete effectively in the global economy. They are also necessary to reinforce the relationship between academia, industry, and government and to encourage technological innovation. Innovation will not only contribute to the growth and development of the SMME sector, but also attract and retain skilled IT professionals and graduates in KZN. The potential of KZN to develop a successful IT sector can be significantly improved by employing a "cluster based approach" to attend to its development needs. The establishment of the Innovation Support Centre in KZN, therefore, can be regarded as a significant tool to promote regional development, and foster innovation and the development of a successful SMME sector in the province, which will in turn contribute to the retention of the skilled IT workforce in KZN. / Thesis (M.A.)-University of Natal, Durban, 2001.

As scaling of CMOS technology continues, the control of parasitic source/drain (S/D) resistance (RSD) is becoming increasingly challenging. In order to control RSD, metallic source/drain MOSFETs have attracted significant attention, due to their low resistivity, abrupt junction and low temperature processing (≤700 °C). A key issue is reducing the contact resistance between metal and channel, since small Schottky barrier height (SBH) is needed to outperform doped S/D devices. A promising method to decrease the effective barrier height is dopant segregation (DS). In this work several relevant aspects of Schottky barrier (SB) contacts are investigated, both by simulation and experiment, with the goal of improving performance and understanding of SB-MOSFET technology:First, measurements of low contact resistivity are challenging, since systematic error correction is needed for extraction. In this thesis, a method is presented to determine the accuracy of extracted contact resistivity due to propagation of random measurement error.Second, using Schottky diodes, the effect of dopant segregation of beryllium (Be), bismuth (Bi), and tellurium (Te) on the SBH of NiSi is demonstrated. Further study of Be is used to analyze the mechanism of Schottky barrier lowering.Third, in order to fabricate short gate length MOSFETs, the sidewall transfer lithography process was optimized for achieving low sidewall roughness lines down to 15 nm. Ultra-thin-body (UTB) and tri-gate SB-MOSFET using PtSi S/D and As DS were demonstrated. A simulation study was conducted showing DS can be modeled by a combination of barrier lowering and doped Si extension.Finally, a new Schottky contact model was implemented in a multi-subband Monte Carlo simulator for the first time, and was used to compare doped-S/D to SB-S/D for a 17 nm gate length double gate MOSFET. The results show that a barrier of ≤ 0.15 eV is needed to comply with the specifications given by the International Technology Roadmap for Semiconductors (ITRS). / QC 20111206

Brain drain and brain circulation are forms of skilled labour migration which have a significant impact on New Zealand’s economic growth. Based on their importance, it is suggested that economies rethink how they compete for skilled labour in an international labour market. This research study reviews economic and non-economic factors that influence an individual’s decisions to stay or leave New Zealand. Data is collected from a survey sample of Lincoln University final year undergraduate and postgraduate students, who represent New Zealand’s future skilled labour. The research study employs a data reduction technique called factor analysis to collate large sets of variables into small sets for econometric analysis. The key econometric tool, logit analysis, provides probabilities of graduates leaving New Zealand and marginal effects of changes in key economic and non-economic variables. These key findings, providing new knowledge, are used to engage in a policy discussion in the last chapter. The research study importantly maintains focus on three key stakeholders, the government, the business community and the individual/student when addressing and analysing New Zealand’s brain drain and brain circulation issues.

Clusters de alta tecnologia são vistos como importantes centros de inovação e produção em uma economia atual global e interconectada. Observa-se um maior interesse da comunidade acadêmica pela relação entre o desenvolvimento de clusters de alta tecnologia em economias emergentes e suas conexões globais através da ‘circulação de talentos entre os clusters’ (em inglês, IBC). IBC representa, tipicamente, a difusão e transferência de tecnologias, conhecimentos e práticas através de redes individuais entre clusters emergentes e clusters já estabelecidos, os quais estão globalmente interconectados através dos laços destas redes. O foco deste estudo está no papel controverso da IBC no estímulo ao crescimento e melhoria de clusters maiores/em crescimento versus clusters menores/nascentes. Este estudo tem como objetivo propor formas de governança da IBC para conduzir estes processos nos seus diferentes estágios de desenvolvimento. O contexto empírico investigado está baseado em (a) dois casos consolidados da literatura: as conexões de Bangalore (IN) - Vale do Silício e Hsinchu (TW) - Vale do Silício; e, (b) dois casos originais: as conexões de Daedeok Innopolis (KR) – EUA e Vale dos Sinos (BR) – Coreia. O método de pesquisa utilizado é qualitativo com a aplicação de 26 entrevistas em profundidade como fonte principal de evidência. Com base nos casos estudados, é possível argumentar que os clusters maiores/em crescimento se beneficiam de uma IBC orgânica, estimulada pelas dinâmicas e forças do mercado, enquanto os clusters menores/nascentes dependem de um esforço coordenado devido à falta de atratividade inicial para empresas e indivíduos. Além disto, com vistas à eficácia da IBC no estimulo ao crescimento e melhoria de clusters, também se pode argumentar que a intervenção nas dinâmicas da IBC se reduz ao longo da evolução dos clusters, passando de um esforço coordenado nos estágios iniciais de desenvolvimento do cluster para um processo orgânico da IBC guiado pelo mercado em estágios mais avançados de desenvolvimento. Este estudo tem implicações importantes no entendimento da conectividade de clusters, do papel da governança para o crescimento e melhoria de clusters e das estratégias efetivas de catch-up para economias emergentes. / High-tech clusters are important hubs of innovation and production in an increasingly interconnected global economy. There has been an increasing interest from scholars in the embeddedness of local cluster development, in particular of high-tech industries in emergent economies, and global connectivity, in particular in the dynamics and role of inter-cluster brain circulation (IBC). IBC denotes knowledge, technology and practice diffusion and translation through individual networks between emergent and typically more established clusters that are globally interconnected through these network ties. Of particular interest to this study is the controversial role of IBC in stimulating the growth and upgrading of larger/growing versus smaller/nascent clusters. Using the lens of network governance, this study aims to propose forms of IBC governance for steering these processes. The empirical context of investigation is composed of (a) two prior studies of IBC in the cases of Bangalore (IN) - Silicon Valley and Hsinchu (TW) - Silicon Valley connections and (b) two original empirical cases examining the Sinos Valley (BR) - Korea connection and Daedeok Innopolis (KR) - US connection. A qualitative research method strategy is employed in these two original cases using 26 in-depth interviews across both cases as a source of evidence. Based on the studied cases, it is possible to argue that for larger-scale growing clusters, IBC-growth dynamics may unfold as an ‘organic process’ through self-reinforcing market forces, whereas small-scale embryonic clusters depend on a ‘coordinated effort’ of this process because they lack initial market attractiveness for both individuals and firms. Further, focusing on the effectiveness of IBC in steering the growth and upgrading of clusters, it can also be argued that IBC governance changes through a gradual decreasing in the intervention to stimulate IBC, from a ‘coordinated effort’ in the early stage to a spontaneous increase in the marketdriven process of IBC as an ‘organic process’ in the mature stage of cluster development. This study has important implications for understanding cluster connectivity, the role of governance in cluster growth and upgrading, and the effective catch-up strategies of emerging economies.

Clusters de alta tecnologia são vistos como importantes centros de inovação e produção em uma economia atual global e interconectada. Observa-se um maior interesse da comunidade acadêmica pela relação entre o desenvolvimento de clusters de alta tecnologia em economias emergentes e suas conexões globais através da ‘circulação de talentos entre os clusters’ (em inglês, IBC). IBC representa, tipicamente, a difusão e transferência de tecnologias, conhecimentos e práticas através de redes individuais entre clusters emergentes e clusters já estabelecidos, os quais estão globalmente interconectados através dos laços destas redes. O foco deste estudo está no papel controverso da IBC no estímulo ao crescimento e melhoria de clusters maiores/em crescimento versus clusters menores/nascentes. Este estudo tem como objetivo propor formas de governança da IBC para conduzir estes processos nos seus diferentes estágios de desenvolvimento. O contexto empírico investigado está baseado em (a) dois casos consolidados da literatura: as conexões de Bangalore (IN) - Vale do Silício e Hsinchu (TW) - Vale do Silício; e, (b) dois casos originais: as conexões de Daedeok Innopolis (KR) – EUA e Vale dos Sinos (BR) – Coreia. O método de pesquisa utilizado é qualitativo com a aplicação de 26 entrevistas em profundidade como fonte principal de evidência. Com base nos casos estudados, é possível argumentar que os clusters maiores/em crescimento se beneficiam de uma IBC orgânica, estimulada pelas dinâmicas e forças do mercado, enquanto os clusters menores/nascentes dependem de um esforço coordenado devido à falta de atratividade inicial para empresas e indivíduos. Além disto, com vistas à eficácia da IBC no estimulo ao crescimento e melhoria de clusters, também se pode argumentar que a intervenção nas dinâmicas da IBC se reduz ao longo da evolução dos clusters, passando de um esforço coordenado nos estágios iniciais de desenvolvimento do cluster para um processo orgânico da IBC guiado pelo mercado em estágios mais avançados de desenvolvimento. Este estudo tem implicações importantes no entendimento da conectividade de clusters, do papel da governança para o crescimento e melhoria de clusters e das estratégias efetivas de catch-up para economias emergentes. / High-tech clusters are important hubs of innovation and production in an increasingly interconnected global economy. There has been an increasing interest from scholars in the embeddedness of local cluster development, in particular of high-tech industries in emergent economies, and global connectivity, in particular in the dynamics and role of inter-cluster brain circulation (IBC). IBC denotes knowledge, technology and practice diffusion and translation through individual networks between emergent and typically more established clusters that are globally interconnected through these network ties. Of particular interest to this study is the controversial role of IBC in stimulating the growth and upgrading of larger/growing versus smaller/nascent clusters. Using the lens of network governance, this study aims to propose forms of IBC governance for steering these processes. The empirical context of investigation is composed of (a) two prior studies of IBC in the cases of Bangalore (IN) - Silicon Valley and Hsinchu (TW) - Silicon Valley connections and (b) two original empirical cases examining the Sinos Valley (BR) - Korea connection and Daedeok Innopolis (KR) - US connection. A qualitative research method strategy is employed in these two original cases using 26 in-depth interviews across both cases as a source of evidence. Based on the studied cases, it is possible to argue that for larger-scale growing clusters, IBC-growth dynamics may unfold as an ‘organic process’ through self-reinforcing market forces, whereas small-scale embryonic clusters depend on a ‘coordinated effort’ of this process because they lack initial market attractiveness for both individuals and firms. Further, focusing on the effectiveness of IBC in steering the growth and upgrading of clusters, it can also be argued that IBC governance changes through a gradual decreasing in the intervention to stimulate IBC, from a ‘coordinated effort’ in the early stage to a spontaneous increase in the marketdriven process of IBC as an ‘organic process’ in the mature stage of cluster development. This study has important implications for understanding cluster connectivity, the role of governance in cluster growth and upgrading, and the effective catch-up strategies of emerging economies.

Os vegetais apresentam defesa natural contra os fatores externos, bióticos e abióticos, por meio da síntese de compostos fenólicos no metabolismo secundário, as quais variam com as fases fenológicas e com o clima. O aumento dos compostos fenólicos nas plantas está, diretamente, relacionado com a resistência à infecção por patógenos e à infestação de pragas. Entretanto, pouco se sabe sobre a variação dos teores dessa substância durante os estádios fenológicos do cafeeiro, em particular, nas fases de frutificação, e em razão das condições climáticas. Tais conhecimentos são fundamentais para a previsão dos riscos de ataques aos vegetais, uma vez que a defesa natural da planta deve mudar ao longo do ciclo. O experimento foi realizado em uma cultura de Coffea arabica L., cultivar Obatã IAC 1669-20, instalada no campo experimental do Departamento de Produção Vegetal, da Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo, Piracicaba/SP. Para a realização do experimento foi adotado o delineamento experimental inteiramente casualizado, utilizando quatro tratamentos (plantas com e sem frutos - folhas dreno e plantas com e sem frutos - folhas fonte) e cinco repetições constituídas por plantas individuais. Após a análise de variância dos resultados foi aplicado o teste t de Student ao nível de 5 % de significância para a comparação das médias entre os tratamentos. Os teores de fenóis totais (µg g-1) foram extraídos das folhas maduras (fonte) e novas (dreno) e analisados em relação à produção de café, fenologia e clima. As variáveis climáticas adotadas foram temperatura atmosférica (média, mínima e máxima; oC), radiação global (MJ m-2 dia-1) e insolação diária (h dia-1). Durante a condução do experimento foram realizadas avaliações de altura da planta (cm), diâmetro do caule (mm) e comprimento de ramos plagiotrópicos (cm) para determinar as respectivas taxas de crescimento vegetativo das plantas. As quantidades de fenóis totais determinadas nas plantas com produção (17.40 µg g-1 e 13.89 µg g-1 folhas dreno e fonte, respectivamente) e sem produção de café (18.65 µg g-1 e 12.76 µg g-1 folhas dreno e fonte, nessa ordem) não variaram. No entanto, a concentração de fenóis totais nas folhas novas (dreno) das plantas com e sem produção de café foi maior que a quantidade determinada nas folhas maduras (fonte), da ordem de 25 % e 46 %, respectivamente. A síntese de fenóis nas fases de expansão (16.35 µg g-1) e granação dos frutos (14.68 µg g-1) foi 31 % inferior em relação às quantidades determinadas na fase de maior produção dessas substâncias – fruto em maturação (21.24 µg g-1). A metabolização de fenóis totais depende, indiretamente, da temperatura (oC) e da radiação global (MJ m-2 dia-1), apresentando tendência inversa em relação a estas variáveis climáticas. A orientação do manejo fitossanitário deve levar em consideração as épocas em que há comprometimento da defesa natural da planta, em relação à produção de substâncias protetivas – os fenóis. / The vegetables show a natural defense against external factors, biotic and abiotic, by the synthesis of the phenolic compounds in the secondary metabolism, which varies with the maturity state and with the climate. The increase of phenolic compounds in the plants is directly related to the resistance to the infection thought pathogens and insect infestation. However, little is known about the variation in the content of this substance during the maturity state of the coffee tree, particularly in the fructification phases due to the climatic variations. Such knowledge is the base for the risks analyses of attacks to vegetables, since the natural defense of the plant shall change during the cycle. The experiment was carried out in a Coffea arabica L. crop, to cultivar Obatã IAC 1669-20, installed in the experimental field of the department of vegetal production of the Escola Superior de Agricultura "Luiz de Queiroz", University of São Paulo, Piracicaba/SP. For the accomplishment of the experiment it was adopted a totally randomized experimental design, using four treatments (plants with and without fruits – drain leaves and plants with and without fruits – source leaves) and five repetitions consisting of individual plants. After analysing the variance of the results it was applied Student t test at the level of 5 % of significance to compare the averages between the treatments. The total phenol grade (µg g-1) have been extracted from the mature (source) and new (drain) leaves and have been analyzed in relation to the coffee yield, phenology and climate. The climatic conditions adopted were atmospheric temperature (average, minimum and maximum; oC), global radiation (MJ m-2 day-1) and daily insolation (h day-1). During the conduction of the experiment it was analyzed the evaluations of the height (cm), diameter (mm) and length of the reproductive branches (cm) to determine the respective vegetative growth rates of the plants. The determined amounts of total phenols in the plants with production (17.40 µg g-1 and 13.89 µg g-1 drain and source leaves, respectively) and without coffee production (18.65 µg g-1 and 12.76 µg g-1 drain and source leaves, respectively) did not varied. However, the total phenol concentrations in new leaves of the plants with and without coffee production were greater than the amount determined in mature leaves around 25 % and 46 %, respectively. The secondary substance synthesis in the phases of expansion (16.35 µg g-1) and grain filling of the fruits (14.68 µg g-1) was 31% lower than the amounts determined in the phase of the greatest production of these substances - fruit in maturation (21.24 µg g-1). The total phenol metabolization depends indirectly on the temperature (oC) and on the global radiation (MJ m-2 day-1), presenting inverse trend in relation to these climatic variable. The orientation of the crop protection managing shall take into consideration the period when it has endangerment of the natural defense of the plant.

A escassez de água no planeta já é uma realidade pontual, inclusive já despontando no horizonte, em nosso país, fora do polígono da seca: na região metropolitana de São Paulo, o modelo de adução, a partir de bacias circunvizinhas, está perto de exaurir, pelos custos que esse tipo de solução adotada desde a época do império romano acarreta nas tarifas para o consumidor final. Assim, a busca pelas chamadas soluções racionais têm, cada vez mais, ganhado adeptos e, dentre estas, a que se tem mostrado mais eficiente e mais eficaz é a tecnologia do esgotamento sanitário a vácuo, visto ser a bacia sanitária a responsável por aproximadamente 40% do consumo residencial de água, e por um percentual semelhante também em edifícios comerciais. A partir do estudo de caso no edifício-sede da Secretaria de Orçamento Federal SOF, em Brasília, foi constatada economia de 30% no consumo médio de água, medido em metros cúbicos, depois da implantação do sistema a vácuo - em substituição ao sistema gravitacional, ocorrida em janeiro de 2008 a par de um aumento de apenas 2% no consumo de energia elétrica, medido em kWh, não produzindo ônus, por força do contrato com a concessionária local de eletricidade, do tipo azul. Foram feitas, ainda, comparações com alternativas de abastecimento, quais sejam água de reuso e o aproveitamento de águas pluviais, este mais comum no Brasil embora nitidamente mais recomendável para construções com até dois pavimentos, enquanto aquele, por enquanto, pode ser considerado uma prospecção teórica para as condições de nosso país / The water shortage in the planet is already a punctual reality that is already rising in our country outside the drought polygon (in northeastern part of Brazil). In the metropolitan area of São Paulo the adduction model coming from the neighboring basins is on the brinks of exhaustion, because this kind of solution costs, adopted since the Roman Empire times, brings up to tariffs to the final customer. In this manner, the search for the so called rational solutions has gained more and more followers and among these the one that has shown more efficiency and accuracy is the vacuum sewerage technology, considering that sanitary basin is responsible for almost 40% of the residential water consumption and a similar percentage occurs also in trade buildings. Taking the case study in the headquarter building of Secretaria de Orçamento Federal (SOF), in Brasília, it was verified a 30% economy in the average water consumption, measured in cubic meters, since the vacuum system was established (replacing the gravitational system), on January 2008, informed about only 2% increase in the electricity consumption, measured in kWh, it means that there was no effective increase in the electricity bill, once the local provide company contract, of the blue type, has foretold small oscillations in the supply without deduction on the bill. It was still done some comparative descriptions with others alternatives water supplies, whichever be grey water and rainwater harvesting, this one widely used in Brazil although it is more suggested to up to two floor buildings while the other, for the time being, can be considered as a theoretical prospection in our country