ABSTRACT Extreme rainfall can lead to heavy damage and losses, such as landslides, floods and agricultural productivity as well as the loss of human and animal lives. To mitigate these losses, water resources management policies are needed, among other goals, to study and predict the frequency of such events in a given region to minimize their harmful effects. The present study investigated the Generalized Extreme Value (GEV) probability distribution applied to the annual maximum daily precipitation data from rainfall stations in the southeastern Brazil. A total of 1,921 rainfall stations were considered, among which the stations with at least 15 years of uninterrupted observations were selected. Subsequently, the stationarity and adherence were tested. GEV probability distribution parameters were then estimated. The results enabled satisfactory spatial interpolation by ordinary kriging and the generation of maps of the distribution parameters. The semivariogram model with the best fit to the three GEV distribution parameters was the exponential model.

In this work a re-investigation of the solubility limits of the (Nb), Nb3Al, Nb2Al and the Nb-rich side of the NbAl3 phases on the Nb-Al system is presented. Alloys in the binary fields ((Nb)+Nb3Al, Nb3Al+Nb2Al and Nb2Al+NbAl3) were arc-melted, and then equilibrated at 1000, 1200 and 1400 ºC. The phases were confirmed via X-ray powder diffractometry, and their compositions were determined via EPMA measurements. The results showed agreement with the literature concerning the solubility limits of (Nb), Nb3Al and NbAl3 phases, while important differences in the values were found for the Nb2Al phase. In addition, the lattice parameters of the Nb2Al phase were determined via Rietveld refinement. This new set of more accurate experimental information indicates that a thermodynamic reassessment is necessary to precisely describe this system.

Resumo O conhecimento da disponibilidade hídrica é básico para a gestão e planejamento dos recursos hídricos. O objetivo deste trabalho foi interpretar as unidades de mapeamento de solos do estado de Minas Gerais sob a ótica dos grupos hidrológicos conforme método do Número da Curva (Curve Number - Soil Conservation Service). Para avaliar os produtos gerados, aplicou-se o procedimento em três ambientes fisiográficos distintos do estado. De acordo com os resultados, a maior parte do estado de Minas Gerais se enquadra nos Grupos Hidrológicos A e B, indicando que os solos nestas áreas apresentam baixo escoamento superficial e alta taxa de infiltração de água. A caracterização e espacialização do regime hidrológico, com ênfase na informação sobre os solos do Estado de Minas Gerais, aplicados neste estudo, tem um nível de detalhe ainda não empregado em estudos deste escopo, além da iniciativa de interpretá-los na perspectiva de grupos hidrológicos do solo. O mapeamento das três unidades de planejamento e gestão de recursos hídricos, compostas por ambientes distintos, na perspectiva dos grupos hidrológicos, permitiu verificar a potencialidade da metodologia proposta, que pode ser utilizada para subsidiar a gestão e o planejamento dos recursos hídricos do Estado de Minas Gerais. Estudos sobre interpretações de mapas de solo do ponto de vista hidrológico são essenciais para melhorar a nossa compreensão sobre os excedentes de água em determinada região.

Abstract The knowledge of water availability is the basis for water resource planning and management. The Soil Map Units of the State of Minas Gerais were interpreted from the perspective of Hydrologic Groups based on the Curve Number - Soil Conservation Service method, with the addition of pedological elements of the mapped units. The generated products were used in three different physiographic environments of the Minas Gerais State. According to results, most of Minas Gerais falls within Hydrologic Groups A and B, indicating that the soils in these areas present low surface runoff and high water infiltration rates. The characterization and spatialization of the hydrological regime, with emphasis on information about the soils of Minas Gerais, as applied this study, has a level of detail not yet employed in studies of this scope, apart from the initiative to interpret them from the perspective of soil hydrological groups. The mapping of the three water resources planning and management units, composed of distinct environments, from the perspective of hydrological groups, allowed verification of the proposed methodology’s potential, which can be used to support the management and planning of the water resources of Minas Gerais. Interpretive studies of soil maps from a hydrological perspective are essential to improve our understanding of water surpluses in a given region.

A recarga do aquífero livre é um dos processos mais importantes na hidrologia das águas subterrâneas, pois constitui reserva renovável deste manancial. Portanto, uma boa estimativa desta variável é fundamental para uma gestão adequada dos recursos hídricos, sobretudo frente à variabilidade climática inerente ao regime climático, assim como o avanço da poluição das águas superficiais e aumento da demanda por águas subterrâneas de boa qualidade. No presente trabalho, foi utilizado um modelo de balanço hídrico do solo para estimar a recarga potencial (Rp) do aquífero livre e os demais componentes do ciclo hidrológico. O modelo foi aplicado em duas bacias hidrográficas de cabeceira do Rio Grande, em Minas Gerais: a Bacia Hidrográfica do Ribeirão Lavrinha (BHRL) e a Bacia Hidrográfica do Ribeirão Marcela (BHRM). A BHRL apresentou maiores valores de Rp, com média anual de 895 mm, o que corresponde a 40% da precipitação média anual, enquanto que na BHRM estes valores foram de 393,3 mm e 25%, respectivamente. Os valores de escoamento de base confirmam essa maior recarga na BRHL, onde este componente da hidrógrafa correspondeu à 76% do total escoado, contra 40% para a BHRM. Com a modelagem empregada, foi possível captar essa diferença, porém seus resultados só foram satisfatórios para um dos anos na BHRL e para todo o período na BHRM, o que reforça a necessidade de utilizar este modelo para longos períodos de tempo.

The free aquifer recharge is a process of major importance in groundwater hydrology because it represents the renewable reserves of the water source. A good estimate of this variable is therefore critical to the proper management of water resources, particularly in light of climate variability inherent to the climate regime, as well as the increasing of surface water pollution and increased demand for good quality water groundwater. This study used a water balance model in soil to estimate the potential recharge (Rp) of the unconfined aquifer and the other components of the hydrological cycle. The model was applied in two watershed headwaters of the Rio Grande in Minas Gerais, Brazil: the Lavrinha River Basin (BHRL) and the Marcela River Basin (BHRM). The BHRL presents higher values of Rp, with an annual average of 895 mm, which corresponds to 40% of rainfall, while at the BHRM these values were 393.3 mm and 25%, respectively. The base runoff values confirm the greater recharge in BRHL, where this hydrograph component corresponded to 76% of the total discharge, compared with 40% for BHRM. The BALSEQ model allowed us to capture this difference, but the results were satisfactory for only one of the years in the BHRL and for the entire period for the BHRM, which reinforces the need to use this model for long time periods.

Alloys containing Me-Si-B (Me - Refractory Metal) are of great interest for high temperature structural applications and accurate knowledge of its low order systems (binaries and ternaries) is important to predict the phase relations in the multicomponent alloys. Recent reevaluations of binaries containing Me-Si found out that the accuracy of the description of this type of systems could be improved. Knowing this, a reevaluation of the invariant reactions in the V-Si system via microstructural characterization of as-cast alloys is presented. Alloys of key compositions were prepared by arc melting pure V (min. 99.75%) and Si (min. 99.998%) and characterized via scanning electron microscopy (SEM) using back-scattered electron (BSE) mode, energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The results of this study confirmed the solid phases, the nature of the invariant reactions and determined new compositions for the liquid participating in certain invariant reactions.

The focus of this work was to determine microstructural features in commercial Ni-Cr alloys which could be used to identify indirectly the presence of beryllium. Thus, eight commercial alloys were characterized by chemical analysis, thermal analysis, X-ray diffraction (XRD), scanning electron microscopy - back-scattered electron images (SEM/BSE), energy-dispersive spectroscopy (EDS). The results indicate that the presence of beryllium can be inferred from microstructural analysis via XRD and SEM/BSE. The X-ray diffractograms of the beryllium-containing alloys showed clearly the existence of the NiBe intermetallic phase. SEM/BSE images of these alloys show a very characteristic eutectic microstructure which also indicates the presence of this element. These characteristics are not observed in the beryllium-free alloys.

A partial isothermal section (Ti-TiSi2-TiB2 region) of the ternary Ti-Si-B system at 1250 ° C was determined from heat-treated alloys prepared via arc melting. Microstructural characterization has been carried out through scanning electron microscopy (SEM), x-ray diffraction (xRD) and wavelength dispersive spectrometry (WDS). The results have shown the stability of the near stoichiometric Ti6Si2B phase and a negligible solubility of boron in the Ti-silicides as well as of Si in the Ti-borides. The following three-phase equilibria have been observed in the Ti- TiSi2-TiB2 region: Ti ss+TiB+Ti6Si2B, Ti ss+Ti6Si2B+Ti5Si3, Ti5Si3+Ti6Si2B+TiB, Ti5Si3+TiB+Ti3B4, Ti5Si3+Ti3B4+TiB2, Ti5Si3+TiB2+Ti5Si4, Ti5Si4+TiB2+TiSi and TiSi+TiB2+TiSi2.

As nascentes são afloramentos dos aquíferos superficiais, e o ciclo da água neste ambiente passa pela recarga que é definida, de maneira geral, como a quantidade de água que é acrescentada ao aquífero, podendo ocorrer localmente a partir da infiltração das águas das chuvas. Neste trabalho, apresenta-se o método de flutuação das superfícies livres (Water Table Fluctuation- WTF) para estimativa da recarga direta e um balanço hídrico subterrâneo para estimativa da recarga profunda, em aquíferos livres. O método WTF utiliza dados de monitoramento do nível do aquífero e rendimento específico do aquífero para a determinação da recarga direta. O balanço hídrico subterrâneo assume a recarga direta estimada pelo método WTF como sendo a entrada de água no sistema, e as saídas, como sendo o escoamento de base e a recarga profunda. As estimativas de recarga foram aplicadas a quatro áreas de recarga de aquíferos superficiais da região do Alto Rio Grande-MG. A estimativa da recarga direta foi de 121,11; 64,62; 83,99 e 152,46 (mm/ano) para as áreas L1, L2, M1 e M2. O efeito da presença de mata na área de recarga pode prevalecer sobre o da declividade do relevo, proporcionando maior recarga direta, mesmo em áreas de recarga com relevo mais íngreme. A drenagem do aquífero superficial (deflúvio propiciado pelas nascentes) no período avaliado superou a recarga direta, indicando uma situação em que a zona saturada, alimenta a zona vadosa.

Springs are outcrops of aquifers surface, and the water cycle in this environment pass through the recharge, generally defined as the amount of water added to the aquifer, which may occur locally from rainwater infiltration. This study uses the Water Table Fluctuation (WTF) method to estimate the direct recharge and a groundwater balance to estimate the deep recharge on unconfined aquifers. The WTF method employs data of the aquifer water levels and its specific yield to estimate the direct recharge. The groundwater balance considers the direct recharge estimated by the WTF method, as the water input in the system and outputs as the base flow and deep recharge. The recharge was estimated at four areas at the watershed of Alto Rio Grande city, Minas Gerais (MG) state, in Brazil. The direct recharge estimate was 121.11; 64.62; 83.99; 152.46 (mm/year) for the L1, L2, M1 and M2 areas. The effect of the presence of forest in the recharge area can prevail over slope of relief, allowing more direct recharge, even in sources with steeper relief. The runoff from the springs in the study period exceeded the direct recharge, indicating a situation in which the saturated zone feeds the vadose zone. The annual flow was above the direct recharge pointing a situation of over exploitation of the aquifer, a non sustainable situation. The specific yield of the aquifers could also have been underestimated.

Recently, a new ternary phase was discovered in the Ti-Si-B system, located near the Ti6Si2B composition. The present study concerns the preparation of titanium alloys that contain such phase mixed with α-titanium and other intermetallic phases. High-purity powders were initially processed in a planetary ball-mill under argon atmosphere with Ti-18Si-6B and Ti-7.5Si-22.5B at. (%) initial compositions. Variation of parameters such as rotary speed, time, and ball diameters were adopted. The as-milled powders were pressureless sintered and hot pressed. Both the as-milled and sintered materials were characterized by X-ray diffraction, scanning electron microscopy and energy-dispersive spectrometry. Sintered samples have presented equilibrium structures formed mainly by the α-Ti+Ti6Si2B+Ti5Si3+TiB phases. Silicon and boron peaks disappear throughout the milling processes, as observed in the powder diffraction data. Furthermore, an iron contamination of up to 10 at. (%) is measured by X-ray spectroscopy analysis on some regions of the sintered samples. Density, hardness and tribological results for these two compositions are also presented here.

Os impactos ambientais de três diferentes tipologias de áreas de disposição de Resíduos Sólidos Urbanos - ADRSU, sobre a qualidade das águas superficiais situadas nas proximidades do aterro sanitário de Campo Belo (Córrego dos Varões), do aterro controlado de Santo Antônio do Amparo (Córrego do Fabiano) e do lixão encerrado de Elói Mendes (Ribeirão Mutuca), municípios situados no Sul de Minas Gerais - Brasil foram avaliados. Para cada curso d'água foram coletadas 5 amostras de água no período chuvoso e 5 amostras no período seco, em três diferentes pontos para cada um dos três cursos d'água sendo: (P1) a montante das ADRSU, (P2) logo após o local de descarga da Estação de Tratamento de Esgoto - ETE (no aterro sanitário, e nas outras tipologias, após ponto de lançamento do escoamento superficial proveniente das ADSRU, e (P3) à jusante das ADSRU. Realizaram-se análises físico-químicas e bacteriológicas, cujos resultados foram analisados com base na estatística descritiva e comparados com valores de referência da Resolução CONAMA 357/2005, bem como utilizados para cálculo do índice de qualidade de água (IQA). Não foi possível detectar efeito significativo das ADRSU, nos parâmetros indicadores da qualidade da água, a qual se apresentou em condições não satisfatórias em função das violações dos parâmetros fósforo, amônia, coliformes termotolerantes e da relação DQO/DBO mesmo à montante da ADSRU. No Ribeirão Mutuca, essa situação foi ainda mais crítica pois o IQA foi classificado como ruim em todos os pontos durante o período monitorado.

The environmental impact of three different urban solid waste facilities (USWF) on the quality of the surface water. The studied areas were the Campo Belo sanitary landfill (Varões River), the controlled landfill of Santo Antônio do Amparo (Fabiano River), and the closed dump of Elói Mendes (Mutuca River), which are cities located in southern Minas Gerais state, Brazil were evaluated. At each sampling point water samples were collected at five occasions in the raining season (October - March) and in the dry season (April - June) at three sampling points: (P1) upstream the solid waste facility, (P2) downstream nearby the point of influx from the sewage treatment plant in the sanitary landfill, or at the drainage point from the surface flow of the dump and controlled landfill, and (P3) downstream the solid waste facility. Physicochemical and bacteriological analyses were performed, and the results were analyzed based on descriptive statistics. The data were also compared with reference values from the National Environmental Council (CONAMA) Resolution 357/2005 and were used to calculate the water quality index (WQI). It was not possible to detect a significant effect of the solid waste facility on the water quality indicators. The water conditions were unsatisfactory due to violations of the concentrations of phosphorus, ammonia, fecal coliform, and the biochemical oxygen demand/chemical oxygen demand ratio (BOD/COD), probably related to other uses along the drainage area upstream the solid waste facility. These conditions were more critical in the Mutuca river, where the WQI was classified as bad during the entire period at all sampling points.

A legislação brasileira estabelece que a água é um recurso natural limitado e dotado de valor econômico; logo, há necessidade de se criar mecanismos para sua adequada gestão. Medidas que estimulam os produtores rurais a adotarem práticas conservacionistas, visando a maior produção de água, melhoria de sua qualidade e redução da produção de sedimentos, vêm sendo estimuladas pelos governos, utilizando para isso até mesmo uma compensação financeira. A partir destas asserções, objetivou-se quantificar os benefícios das ações de conservação nas unidades de gestão e definir um Indicador de Produção de Água (IPA) para a tomada de decisão em uma bacia hidrográfica da região Alto Rio Grande-MG. Para avaliar o impacto das ações, foram definidos 4 cenários de uso e ocupação do solo da bacia hidrográfica do Ribeirão Marcela, localizada na UPGRH-GD1 (Alto Rio Grande). Após a análise dos resultados obtidos, chegou-se à conclusão de que as simulações de diversos cenários demonstraram alterações na produção de água e que a definição do Indicador de Produção de Água, a partir da junção do potencial de erosão com o potencial de armazenamento, demonstrou ser eficaz, pois integrou quantidade e qualidade de água.

The Brazilian Law stipulates that water is a limited natural resource doted of economic value, thus it is necessary to develop mechanisms for its adequate management. Actions that encourage the farmers to apply soil conservation practices with the purpose of increase water yield from springs and to promote improvement of its quality, reducing production of sediment transportation, is being encouraged by governments, even with financial compensation for owners. From these assertions, this study aims to quantify the benefits of the conservation actions of the management units and to characterize a Water Yield Indicator (WYI) to support sustainable actions in the watershed of Alto Rio Grande region, in the state of Minas Gerais (MG). To assess the impact of actions it were identified four scenarios of land use and occupation of the watershed from Marcela stream which is located in Alto Rio Grande Region. After analyzing the results, it can be stated that the scenarios simulation has demonstrated important changes in water yield and that the definition of the Water Yield Index from the junction of the erosion potential with the water storage potential, has proved effective, as it integrate quantity and quality of water.

An accurate knowledge of several metal-boron phase diagrams is important to evaluation of higher order systems such as metal-silicon-boron ternaries. The refinement and reassessment of phase diagram data is a continuous work, thus the reevaluation of metal-boron systems provides the possibility to confirm previous data from an investigation using higher purity materials and better analytical techniques. This work presents results of rigorous microstructural characterization of as-cast hafnium-boron alloys which are significant to assess the liquid composition associated to most of the invariant reactions of this system. Alloys were prepared by arc melting high purity hafnium (minimum 99.8%) and boron (minimum 99.5%) slices under argon atmosphere in water-cooled copper crucible with non consumable tungsten electrode and titanium getter. The phases were identified by scanning electron microscopy, using back-scattered electron image mode and X-ray diffraction. In general, a good agreement was found between our data and those from the currently accepted Hafnium-Boron phase diagram. The phases identified are αHfSS and B-RhomSS, the intermediate compounds HfB and HfB2 and the liquide L. The reactions are the eutectic L ⇔ αHfSS + HfB and L ⇔ HfB2 + B-Rhom, the peritectic L + HfB2 ⇔ HfB and the congruent formation of HfB2.

Neste trabalho se estimaram os valores prováveis de precipitação pluvial para períodos quinzenais e suas respectivas distribuições espaciais, em Guiné-Bissau. Utilizou-se a distribuição log-normal a dois parâmetros para estimar os valores prováveis de precipitação associados ao nível de probabilidade de 75%, entre os meses de junho a outubro. A variabilidade espacial foi estimada pela modelagem dos semivariogramas experimentais e expressa com o emprego do interpolador espacial krigagem. Em média pode-se esperar, para períodos quinzenais em 3 de cada 4 anos pelo menos 100mm de chuvas, excetuando-se a 1ª quinzena de junho e a 2ª quinzena de outubro, cujos valores estimados estão abaixo de 50mm. Essas duas quinzenas correspondem, respectivamente ao início e ao fim do período de chuvas sinalizando, portanto, a necessidade de uso de irrigação suplementar para os cultivos agrícolas, visto que, em junho ocorre a semeadura e outubro antecede a colheita para culturas de ciclo longo. Quanto à variabilidade espacial, ela é elevada, com evidente decréscimo dos índices pluviométricos do eixo sul-sudoeste, exceto no mês de setembro, quando há homogeneidade espacial nas duas quinzenas.

The aim of this study was to estimate the probable values of rainfall in the first and second halves of the months and its spatial distribution in Guinea-Bissau. Distribution functions Log-normal 2 parameters were used to estimate the probable values of rainfall adopting the probability level of 75%. The spatial interpolation (kriging) was applied by semi-variogram modeling demonstrating that the probable rainfall estimates have high spatial variability, except in the month of September, when the behavior is homogeneous for both first and second halves. The lowest probable values of rainfalls under 50 mm occur in June and October throughout the country, supporting the use of supplemental irrigation to avoid compromising the periods of sowing (June) and minimize damage at harvest (October, November) for long cycle crops.

Conduziu-se este trabalho, com principal objetivo de estudar o comportamento da qualidade da água, ao longo do tempo, em uma bacia hidrográfica de cabeceira do Rio Grande, MG. A bacia hidrográfica apresenta uma área de 687 ha e está situada na Serra da Mantiqueira. Foram amostrados seis pontos no Ribeirão Lavrinha no período de maio de 2006 a janeiro de 2007, totalizando sete amostragens. O mapa de uso atual do solo foi gerado a partir de levantamento em campo com auxilio de GPS. Os parâmetros analisados foram: potencial hidrogeniônico (pH), oxigênio dissolvido (OD), condutividade elétrica, salinidade, temperatura, demanda bioquímica de oxigênio (DBO), demanda química de oxigênio (DQO), nitrato (NO3-), nitrogênio amoniacal (NH3), fósforo (PO4), turbidez, sólidos totais, sólidos totais dissolvidos (TDS), coliformes termotolerantes (Escherichia coli), coliformes totais. Para os dados calculou-se o Índice de Qualidade da Água (IQA), proposto pelo Instituto Mineiro de Gestão das Águas (IGAM) e fez-se o enquadramento em classes conforme Resolução 357/05 CONAMA. As condições ambientais refletiram-se tanto nos valores do IQA quanto no processo de enquadramento. Constatou-se ainda que o principal fator causador do quadro crítico é o NMP de coliformes, o qual se associa com a pecuária. Em menor escala o OD e a DBO são também fatores limitantes.

The main purpose of this work was to study the surface water quality behavior, continuously throughout the time, at the headwater watershed of the Grande River, MG. The watershed drains into Grande River area of 687 ha and is enclosed by the Mantiqueira Mountains. The samples were collected at six points in Lavrinha Stream, main tributary of the watershed, from May 2006 to January 2007, with a total of seven evaluations for each point. Current watershed land use map was developed through GPS device, based on field observations. The parameters evaluated were: hydrogen potential (pH), Dissolved Oxygen (DO), electric conductivity (EC), salinity, temperature, Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), nitrate (NO3-), ammonia (NH3), phosphorous (PO4), turbidly, total soil, total dissolved soil (TDS), fecal coliform (Escherichia coli), total coliform. Water Quality Index (WQI), proposed by "Minas Gerais State Water Resources Institute" (IGAM), was calculated for all samples, classifying the water quality class according to CONAMA Resolution 357/05. The environmental conditions reflected on WQI values as well as on CONAMA water quality classification. It was evidenced that the main parameter of the critical situation of the water quality at watershed was the fecal and total coliform, which is associated to livestock. Although less important than coliform, DO and BOD are also limiting parameters at watershed.

Objetivou-se, no presente trabalho, avaliar o efeito de épocas de irrigação e de parcelamentos de adubação sobre a produtividade do cafeeiro. O delineamento experimental utilizado foi em blocos casualizados com parcelas subdividas em faixas. O experimento foi composto por 4 blocos (repetições), cada bloco foi dividido em 4 parcelas, que receberam o efeito de diferentes parcelamentos de adubação (4, 12, 24 e 36 aplicações de fertilizantes), as parcelas foram subdivididas em 5 subparcelas, correspondentes às diferentes épocas de irrigação: "A" entre 01/06 e 30/09, "B" entre 15/07 e 30/09, "C" de 01 a 30/09, "D" entre 01/06 e 30/09 com adubação manual e "E" não irrigada. Promoveu-se análise de variância sobre os dados de produtividade, identificando-se que houve efeito apenas do fator épocas de irrigação sobre a mesma. O teste de comparação de médias possibilitou concluir que a irrigação entre 01/06 e 30/09, seja com o uso de fertirrigação ou com aplicação manual de fertilizantes, proporcionou as melhores médias de produtividade.

This work aimed to evaluate the irrigation time and fertilizer splitting effects on coffee crop productivity. Random blocks with parcels subdivided into strips were the experimental design applied. The blocks had four replications and were divided into four plots. These plots (4, 12, 24 and 36 fertilizer applications) were subdivided into five subplots associated to different irrigation times: "A" between 06/01 and 09/30, "B" between 07/15 and 09/30, "C" between 09/01 and 09/30, "D" between 06/01 and 09/30 with manual application of fertilizer and "E" without irrigation. Analysis of variance was applied to evaluate the coffee crop productivity, which showed that only the irrigation time factor was effective. The mean comparison test allowed concluding that irrigation between 06/01 and 09/30, with fertigation or with manual application of fertilizer, produced the best productivity means.