Seletividade de herbicidas: II - aplicação de herbicidas em pós-emergência inicial e tarida da cana-de-açúcar na época das chuvas

Objetivou-se com este trabalho testar a seletividade dos herbicidas diuron+hexazinone, azafenidin+hexazinone, metribuzin e isoxaflutole, aplicados em pósemergência inicial e tardia das plantas de cana-de-açúcar, cultivar RB835089, na época das chuvas, em soqueira de terceiro corte, após colheita com queima prévia do canavial, em Araras-SP. O delineamento experimental foi o de blocos casualizados com testemunhas pareadas, com cinco tratamentos e quatro repetições, existindo uma testemunha capinada para cada tratamento químico dentro de cada bloco. Os tratamentos foram: diuron+hexazinone (1.170+330 g ha-1), azafenidin+hexazinone (192,5+247,5 g ha-1), metribuzin (1.920 g ha-1), isoxaflutole (127,5 g ha-1) e testemunha. Concluiu-se que os herbicidas foram mais fitotóxicos quando aplicados na pós-emergência tardia. em pós-emergência inicial, o isoxaflutole foi o único produto que afetou a produtividade agrícola. Na pós-emergência tardia, todos os herbicidas prejudicaram a produtividade agrícola, sendo o diuron+hexazinone o único produto que não afetou as características tecnológicas e o rendimento de açúcar.

Perdas de nutrientes por erosão e sua distribuição espacial em área sob cana-de-açúcar

O presente trabalho teve como objetivo principal determinar as perdas de nutrientes por erosão em entressulcos, sulcos e global (entressulcos + sulcos, A), em área cultivada com cana-de-açúcar submetida à queima da palhada na sua pré-colheita, na Fazenda Santa Bárbara, localizada em Guariba - SP, sob um Latossolo Vermelho eutroférrico (LVef). Parcelas experimentais foram submetidas à chuva simulada com intensidade de 80 mm h-1, durante 65 minutos. Análises do sedimento erodido indicaram altas taxas de enriquecimento: 1,62 (matéria orgânica, MO); 4,30 (P); 1,17 (K); 1,33 (Ca) e 1,24 (Mg) vezes em relação ao solo original. As perdas de solo e nutrientes, em função do tipo de erosão, obedeceram à seguinte ordem: sulcos > global > entressulcos. Análises geoestatísticas indicaram que as perdas de solo (A), MO, P, K e Ca por erosão apresentaram forte grau de dependência espacial, enquanto as perdas de Mg tiveram moderado grau de dependência espacial. Mapas da distribuição dos padrões de variabilidade espacial das perdas por erosão indicaram que o cultivo de cana-de-açúcar conserva as propriedades químicas e físicas do solo na maior parte da área.

Avaliação da incorporação de cinzas de lodo de esgoto como adição mineral em concretos de cimento Portland

O desenvolvimento das grandes cidades tem gerado um dos maiores desafios ambientais enfrentados na atualidade, que é a gestão eficaz de resíduos sólidos. A grande variedade e quantidade dos resíduos produzidos diariamente, tem tornado a destinação ecologicamente correta e sustentável destes materiais cada vez mais difícil. Dentre os vários resíduos produzidos diariamente destacam-se os lodos oriundos de estações de tratamento de esgotos, denominados de lodos de esgoto, cuja destinação final segura tem sido discutida mundialmente em diversos estudos, tendo em vista que a tendência de geração deste tipo de resíduo tende a crescer com o aumento do saneamento das cidades. Uma forma amplamente difundida nos países desenvolvidos para destinação dos lodos de esgoto é a incineração destes materiais para posterior envio das cinzas geradas neste processo a aterros sanitários. Porém, tem-se estudado formas alternativas de disposição, destacando-se a utilização destas cinzas como adição mineral em concretos e argamassas de cimento Portland. Sabe-se que o desempenho de resíduos de incineração como adição mineral em matrizes cimentícias, depende em grande parte da capacidade de atuação destes materiais como elementos pozolânicos ou como fileres, podendo estas características serem influenciadas pela temperatura de queima ao qual estes resíduos foram submetidos. Neste sentido, verificou-se com esta pesquisa a influência da temperatura empregada na queima dos lodos sépticos no índice de atividade pozolânica (IAP) das cinzas geradas como resíduo deste processo, aqui denominadas de cinzas de lodo séptico (CLS), sendo em seguida, avaliadas as implicações técnicas e microestruturais da utilização deste resíduo em teores de 10%, 20% e 30% como adição mineral em concretos de cimento Portland. Os resultados obtidos demonstraram não haver alterações significativas no IAP das CLS em decorrência da temperatura utilizada durante o processo de queima dos lodos de esgoto. Além disso, verificou-se que embora a utilização das CLS tenham provocado diminuição da trabalhabilidade dos concretos para todos os teores de incorporação, estas melhoraram a resistência mecânica à compressão, o índice de vazios, a absorção de água e o comportamento microestrutural dos concretos contendo 10% e 20% de resíduo

Comportamento de atributos físicos de um Latossolo Amarelo sob agroecossistemas do Amazonas

O desmatamento da floresta tropical da Amazônia e a utilização do solo para fins agrícolas potencializam sua degradação física, química e biológica, quando realizados de forma inadequada. Este estudo teve o objetivo de avaliar o efeito de sistemas de uso e manejo de um Latossolo Amarelo, muito argiloso, mediante avaliações de atributos físicos determinados nas profundidades de 0,0-0,2 e 0,2-0,4 m, em área da Universidade do Amazonas, Manaus (AM). Os sistemas de uso e manejo foram: milho, laranja, pupunha, guaraná, pastagem, capoeira e floresta. Nos sistemas com milho, laranja, pupunha e pastagem, foram realizados o desmatamento, a queima e as operações de preparo e cultivo mecanizados. Foram avaliados a composição granulométrica, o grau de floculação da argila, o teor de matéria orgânica, a densidade de partículas, a densidade do solo, a porosidade total, a macro e microporosidade, e a infiltrações inicial e básica. Utilizou-se o delineamento experimental inteiramente casualizado, com três repetições. Os agroecossistemas, em ordem crescente: capoeira, guaraná, milho, laranja, pupunha e pastagem induziram uma degradação dos atributos físicos do solo cultivado em relação ao de floresta, quantificada pelos maiores valores de densidade do solo e menores de macroporosidade, infiltração de água e matéria orgânica.

Spatial variability of soil physical properties in two management systems in sugarcane crop

O objetivo deste trabalho foi caracterizar a variabilidade espacial da densidade do solo (Ds), teor de água no solo (θ) e porosidade total (Pt) em dois sistemas de manejo da colheita da cana-de-açúcar, com queima e sem queima, em um Latossolo Vermelho, na camada de 0-0,20 m. A área de estudo está localizada no município de Rio Brilhante-MS, na Usina Eldorado. A parcela de cada talhão apresentou malha com comprimento de 180 m e largura de 145,6 m, perfazendo 90 pontos distribuídos na forma de uma grade de nove colunas por dez linhas, com pontos distanciados 20 m de seu vizinho. Foram coletadas amostras de solo na camada de 0-0,20 m, nos anos agrícolas de 2007/2008 e 2008/2009. O sistema de colheita com queima apresentou maior densidade em relação ao mecanizado, nos dois períodos de análise. O teor de água no solo, assim como a porosidade, teve aumento proporcional com relação à diminuição da densidade do sistema de colheita com queima para com o mecanizado.

Utilização de redes neurais artificiais para detecção e diagnóstico de falhas

In a real process, all used resources, whether physical or developed in software, are subject to interruptions or operational commitments. However, in situations in which operate critical systems, any kind of problem may bring big consequences. Knowing this, this paper aims to develop a system capable to detect the presence and indicate the types of failures that may occur in a process. For implementing and testing the proposed methodology, a coupled tank system was used as a study model case. The system should be developed to generate a set of signals that notify the process operator and that may be post-processed, enabling changes in control strategy or control parameters. Due to the damage risks involved with sensors, actuators and amplifiers of the real plant, the data set of the faults will be computationally generated and the results collected from numerical simulations of the process model. The system will be composed by structures with Artificial Neural Networks, trained in offline mode using Matlab®

Estudo da Potencialidade da produção de tijolos de adobe misturado com outros materiais: uma alternativa de baixo custo para a construção civil

The production of the red pottery brick, made traditionally with clay, is a technique that is already stabled. However, in spite of the little complexity that involves the conventional process of these bricks production, it are exposed to many problems that begin in the fase of exploration of the mines, the problems get worse because of the lack of the clay's characterization, and they continue through the steps of the dough preparation, conformation of the products, the drying and the burning process. The wastefulness is shown and so is the low quality of the material produced. Among other factors, the high use of energy in the burning makes the cost of this material inaccessible to the low income consumer. Besides this, the destruction of the environment around the mines and the use of native vegetation to produce wood - the most used fuel in the pottery industry - make serious environmental damage. The production technique of a new type of simple brick (adobe), that has low cost and no environmental damage, can be the viable altemative to lower the cost of this part of the civil construction, and, consequently, in the building of cheaper houses. In this paper, the results of the mechanical resistance of the adobe brick are shown, using in its composition, clay, natural vegetable fibers, cement and plaster in a process that is completely handcrafted and manual. It is intented to make clear that are possible alternatives to be put in practice, with the simple process, using "raw earth" that has been used in the construction of houses in thousands of years, trying to solve these severe problems. Analysis and tests were performed to find results that could prove the possibility of the utilization of this kind of material. Other studies are in progress, and the new researches are necessary to enrich this work, but it stays the certainty that there is potential to produce bricks from adobe, as an alternative that has low cost to civil construction

Utilização de resíduos de rochas ornamentais na produção de cerâmica branca

The marble and granite waste come from the process of mining of those ornamental rocks for use in the building industry. Brazil is one of the largest producers of blocks or finished products of ornamental rocks, extracting about 5.2 tons / year. The largest national producers are the states of Espírito Santo, Minas Gerais and Bahia which account for 80% of the Brazilian production. However, the waste total amount during processing of these blocks reaches 40% of the total. The use of the waste produced by this industry in white ceramics could be a form of disposition, because these materials, are thrownasa mud directly at decantation ponds, wastelands or in rivers, without any treatment. The present work has as main purpose to study the influence that reject of the ornamental rocks on the physical and mechanical properties of white ceramics. X-Ray characterizations of raw materials by were performed X-Ray fluorescence, X-Ray diffraction, granulometric, thermogravimetric and thermodiferencial analysis, five formulations were made (0, 10, 20, 30, 40% in granite weight) wich were burned at three temperatures: 1100°C, 1150°C and 1200ºC with 60 minutes of sorling time. After sintering, the samples were submitted to different analyser absorption of water, linear retraction, apparent porosity, apparent specific mass, flexival stronght, and scanning were obtained microscopy. Compatible technological properties within the limits demanded for the production of porcelainized stoneware

Efeito da introdução de resíduo de cinza de forno cerâmico em massa para cerâmica estrutural

The red ceramics and structural ceramics, as they are known, include ceramic materials made by blocks of seals and structures, bricks, tiles, smail flagstones manacles, rustic floors and ornamental materials. Their fabrication uses raw material such as clay and clay sites, with some content of impurity. It has good durability and mechanical strength to compression, low cost, making it one of the mainly used materials in civil engineering. The incorporation of many industrial activities residue to ceramic products is a technological alternative for reducing the environmental impact caused by its carefree disposal. This incorporation can promote chemical change and inertness of metals from residue, by fixation in the glassy phase of ceramic during the burning stage. The main aim of this project is to study the technical feasibility of the addition of ceramic oven ash into formulations of mass for structural ceramics. In this project two kinds of clay (plastic and non-plastic) were used, as well as the ash from firewood used in the process of burning of structural ceramics. A group of experiments was outlined, which permitted the evaluation of the influence of the burning cycle in different temperatures of the ash content in formulations for ceramic blocks through technological properties, mechanical behavior and microstructure. Five samples were processed of each one of the masses of plastic and non-plastic clay without addition of ash and with addition of ash on the percentages of 10 % and 20 %, for temperatures of 850 °C, 950 °C, 1050 °C and 1150 °C, obtained through sinterization process. Among the studied compositions, the one which presented best performance was the mass of clay with 10 % of ash, at temperature of 1150 °C, with the smallest absorption of water, the smallest apparent porosity, specific apparent mass a bit over the others and greatest mechanical resistance to flexion. The composition made confirmed the technical feasibility of the use of ash in the mass for structural ceramics with maintenance of its necessary characteristics for its purposes

A influência da adição de caulim, quartzo e feldspato potássico na formulação de massas cerâmicas para telhas: Modelo estatístico

The production of roof tiles in the state of Rio Grande do Norte accounts for around 60% of the total of ceramic pieces produced. There is a need for investment to improve quality and productivity, thereby promoting technological innovations. Accordingly, the aim of this study is to determine the effect of kaolin, potassium feldspar and quartz in two standard formulations, as well as the effect of sintering temperature on the technological properties of linear firing shrinkage, water absorption and bending rupture stress, by fitting the statistical model and using multiple linear regression to assess the relationship between technological properties and independent variables. The raw materials were characterized using the following techniques: X-ray fluorescence (XRF), X-ray diffraction (XRF), rational analysis (RA), differential thermal analysis (DTA) and granulometric analysis (GA). The test specimens were compacted by uniaxial pressure (25 MPa), dried in a stove at 110 ºC for 24 hours and sinterized at 850 ºC, 950 ºC and 1050 ºC and held isothermal for 30 minutes. The results obtained indicate that the addition of kaolin to two standard formulations (M and R) promoted a reduction in water absorption values and an increase in bending rupture stress values. The sintering temperatures for group M that resulted in the lowest linear firing shrinkage and water absorption values were 850 ºC and 950 ºC, respectively, and the highest bending rupture stress values were reached at a temperature of 950 ºC. In the case of group R, the sintering temperature that obtained the lowest water absorption and linear firing shrinkage values was 850 ºC, and the highest bending rupture stress values were attained at a temperature of 1050 ºC. This work explains the statistical approach used to fit the model that describes the relationship between the technological properties and percentage of kaolin, quartz and feldspar, as well as the models that enable predictions, provided that the lower and upper limits of the percentage of clay minerals, flux and quartz used in this study are respected. Statistica 6 software was used and results were obtained by stepwise forward regression

Estudo da formulação de massas cerâmicas provenientes da região do Seridó-RN para fabricação de telhas

This work has for objective study compared the characteristics and technological properties of ceramic bodies from the region of Seridó-RN. The region under study has identified 23 cities where they were 80 ceramics industries. To define the universe of search, there was a survey of pottery that are part of APL Seridó next to the IEL. The characteristics and operating conditions of ceramics industries of the region were identified through a socio-economic questionnaire applied locally, which addressed issues such as: profiles of companies, production process etc. The analysis of information collected from 24 companies identified in seven cities shows that the vast majority of industries is small, with family structure, obsolete equipment and labo, little qualified. Most of the pottery works with low technical knowledge, poor control of the production process and product technology. The raw collected were submitted to analysis of X ray diffraction, chemical composition, termical analysis, particle size distribution and plasticity. Then were produced five formulations and made by uniaxial pressure at 25 MPa for firing in temperatures varying from 850 to 1050 °C. The firing technological properties evaluated were: mass loss to fire, lineal shrinkage, apparent density, apparent porosity, water absorption and flexural strength (3 points). The results indicated that the raw materials from the region have significant similarities in the composition chemical and mineralogical. Furthermore, it indicates the possibility of the use of cycles of firing faster and efficient than the current, limited to some clay mass burning of certain conditions

Caracterização de matérias-primas regionais e desenvolvimento de formulações de massas cerâmicas para porcelanato

Initially concentrated in some poles at the South and Southeast regions of Brazil, the ceramic tiles industry became wide during the 80 s decade, with a disconcentration industrial and regional pulverization. The competitiveness in the ceramic tiles internal and external consumers markets, it has debtor the industries to invest in sophisticated products each time more, either in design or the technology, but, mainly, in its final properties. Amongst the diverse types of ceramic coating, the porcelanato if has detached had to its process of technological production and excellent characteristics techniques. The Porcelanato is currently the material for coatings that presents the best technical and aesthetic features when compared with others ceramics found on the market. The chemical composition and the others raw materials characteristics have an importance that must to be ally to the inherent characteristics of fabrication process, essentially those related to the cycle of burning. This work had as purpose to develop formularizations of ceramic mass for production of porcelanato without glass coating, pertaining to the group BIa (text of absorption of water ≤ 0.5%) and with resistance superior mechanics 35MPa from raw materials characterized. The ceramic raw materials selected to the development of this study (A1 and A2 clays, feldspate, talc and quartz) were submitted to the following tests: X-ray fluorescence - chemical analysis determination; X-ray diffraction - Analysis of the stages mineralogics; Laser granulometry - size distribution of particles; and Differential thermal analysis - thermal behavior. Were performed tests of absorption of water, lineal retraction of it burns, apparent specific mass and rupture tension the flexing. The results had evidenced that the formularizations that had the A1 clay and talc on its composition were efficient for the porcelanato production remaining their technological characteristics inside of the intervals of variation desired by the Norms of the ABNT

Estudo do efeito do óxido de bário no comportamento de massas para porcelanato

In this work, it is proposed the study of the effect of barium oxide acting as synthetic flow in the behavior of masses for stoneware from the use of raw materials found in the deposits of minerals of the Rio Grande do Norte that it makes use of a great natural potential for the industrialization of the product. The porcelanato is a sophisticated product with excellent final properties being applied as ceramic coating in buildings of high standard of engineering. The raw materials selected for the development of the study had been two types of argilas, two types of feldspatos, dolomita, talco, barium carbonate and silica, being characterized by X-ray fluorescence, X-ray diffraction, granulometric analysis, dilatometric analysis and thermal analysis. Thus, it is intended to define four formulations using the cited raw materials that will be processed, conformed and sintered in the temperatures of 1150 °C, 1175 °C, 1200 °C, 1225 °C e 1250 °C. From the physical characterizations, chemical and morphologic of the formed formulations, the effect of barium oxide is determined in the physical and mechanical properties of the studied system carrying water absorption tests, linear retraction, apparent porosity, apparent specific mass, compacting curve, flexural strength and microstructural analysis by XRD and SEM. After analyzing the results, indicated that barium oxide acts as a flux of high temperature and as the ordering of structure, where the embedded glass phase has the nucleating effect phase potassium silico-aluminum reacting with free silica which together with the high content of potassium concentrated form a new crystalline phase called microcline. The masses studied with the addition of barium oxide present physical-mechanical properties highly satisfactory in reduced firing temperatures, which implies a saving in energy given off in the production and increased productivity

Sorção de petróleo por fibras vegetais

Nowadays, when accidents with oil tanker or shore tanks occur and there is oil spill, some arrangements are made in order to repress and to fix the situation. For the containment, barriers or detours are usually made of synthetic materials such as polyurethane foam. In order to clear water away, techniques like in loco burning, biodegradant agents, dispersant agents and sorbent materials application are used. The most of the sorbent materials are also synthetic and they are used because it is easy to store them and their availability in market. This dissertation introduces the study of vegetable fibers of pineapple leaf fibers (Ananas comosus (L.) Merr.), cotton fibers (Gossypium herbaceum L.), kapok fibers (Ceiba pentandra (L.) Gaertn.), curauá fibers (Ananas erectifolius L.B. Sm.) and sisal fibers (Agave sisalana Perrine) related to their capacity of sorption of oil in case of accidental spill in the ocean. This work evaluates the substitution possibility of synthetic materials by natural biodegradable materials with less cost

Produção de grês porcelanato a partir de matérias-primas do estado da Bahia

The State Bahia, Brazil, presents different geological sites it with a very expressive variety minerals. It is situated among the very important States which produces minerals for industries, such as pointed aggregate, ornamentals stones and ceramics raw materials. Nowadays only four companies producting ceramics tiles. Porcelainized stoneware tiles is one of the noblest ceramics, depicting low water absorption (typically below of 0,5%), in addition to excellent staining resistance and mechanical strength. The present work aims at investigating the potential of local raw materials for the production of porcelainized stoneware tiles. For this purpose, these materials were characterized by X-ray fluorescence, X-ray diffraction, particle size analysis, thermal gravimetric analysis, thermal differential analysis and dilatometric analysis. Admixtures containing different compositions were prepared and fired at four temperatures, 1100 ºC, 1150 ºC, 1200 ºC and 1250 ºC with isotherm for 60 minute and heathing rate of 5 oC/min. After firing the samples, they were characterized by water absorption tests, linear retraction, analysis, apparent porosity, apparent specific mass, flexural strength, and microstructural analysis by X-ray diffraction and scanning electron microscopy . The results revealed three ceramics with porcelainized stoneware tiles characteristics and porcelain tile will be produce from raw materials originated in the State of Bahia