Análise dos sprays de jatos de injetores de motor foguete utilizando um sistema de processamento digital de imagens

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Nutrient contents and production of rocket as affected by nitrogen concentrations in the nutritive solution

O empirismo no uso das soluções nutritivas é freqüente. Muitas vezes a mesma solução nutritiva é usada para diferentes espécies baseando-se apenas em semelhanças morfológicas. No entanto esta situação pode proporcionar desequilíbrio nutricional prejudicando tanto a produção quanto a qualidade do produto face o acúmulo de nitrato. Foi conduzido um trabalho em sistema hidropônico - NFT, com o objetivo de avaliar o efeito da concentração de nitrogênio na solução nutritiva na produção, nos teores de nutrientes e de nitrato em folhas de rúcula (Eruca sativa). O trabalho foi conduzido na primavera de 2003. Foram avaliadas quatro concentrações de nitrogênio na solução nutritiva (60,8; 121,6; 182,5; 243,5 mg L-1) e três cultivares de rúcula (Cultivada, Folha Larga e Selvática), sob delineamento de blocos ao acaso, fatorial 4 x 3, com quatro repetições. A cv. Cultivada apresentou maior estatura e fitomassa fresca de folhas, não diferindo da 'Folha Larga' quanto a número de folhas, teor de nitrato nas folhas e fitomassa seca e fresca da raiz. Houve incremento de NO3-, N, Ca e P e diminuição de Mg, K e S com o aumento da concentração de N na solução nutritiva. O cultivo da cv. Cultivada na concentração de 93 mg L-1 é a mais recomendada em função da maior produtividade e baixo teor de nitrato.

Nitrogen fertilization on intercropping of lettuce and rocket

O trabalho foi conduzido na UNESP, Jaboticabal-SP, de setembro a dezembro de 2006, com objetivo de avaliar o efeito da adubação nitrogenada em consórcio de alface e rúcula. O delineamento experimental foi de blocos casualizados completos, com quatro repetições, sendo os tratamentos arranjados em esquema fatorial 4 x 4 + 2. Os tratamentos resultaram da combinação de quatro doses de N para a alface (0, 65, 130 e 195 kg ha-1) e quatro doses de N para a rúcula (0, 65, 130 e 195 kg ha-1), mais dois tratamentos adicionais, correspondentes aos monocultivos de alface e rúcula. As cultivares utilizadas foram Verônica (alface) e Folha Larga (rúcula). O aumento da dose de N para ambas as culturas, em consórcio, proporcionou incrementos na massa fresca e produtividade de alface e da rúcula e maximizou o índice de eficiência de uso da área (1,84) na dose 127 kg ha-1 de N para a alface e 195 kg ha-1 de N para rúcula.

Assessment of agroeconomic indices in polycultures of lettuce, rocket and carrot through uni- and multivariate approaches in semi-arid Brazil

The polyculture among vegetables is an activity that to have good results, needs a proper planning. Although it often requires more labor, has several advantages over monoculture, among them is that polycultures are generally are more productive, provide with productivity of various plant constituents and a more balanced human diet, contribute to economic return, economic and yield stability, social benefits and farmer's direct participation in decision-making. The objective of this study was to evaluate agroeconomic indices of polycultures derived from the combination of two cultivars of lettuce with two cultivars of rocket in two cultures strip-intercropped with carrot cultivar 'Brasilia' through uni-multivariate approaches in semi-arid Brazil. The experimental design used was of randomized complete blocks with five replications and the treatments arranged in a factorial scheme of 2 x 2. The treatments consisted of the combination of two lettuce cultivars (Baba de Verao and Taina) with two rocket cultivars (Cultivada and Folha Larga) in two cultures associated with carrot cv. Brasilia. hi each block were grown plots with two lettuce cultivars and two rocket cultivars, and carrot in sole crop. In each system was determined the lettuce leaf yield, rocket green mass yield and carrot commercial yield. Agrieconomic indices such as operational cost, gross and net income, monetary advantage, rate of return, profit margin, land equivalent ratio and yield efficiency for DEA were used to measure the efficiency of intercropping systems. In the bicropping of lettuce and rocket associated with carrot cv. 'Brasilia', suggests the use of lettuce cultivar 'Taina' combined with rocket cultivars 'Cultivada' or 'Folha Larga'. It was observed significant effect of lettuce cultivars in the evaluation of polycultures of lettuce, carrot and rocket, with strong expression for the lettuce cultivar 'Taina'. Both uni- and multivariate approaches were effective in the discrimination of the best polycultures. (C) 2011 Elsevier Ltd. All rights reserved.

Determination of ecological efficiency in internal combustion engines: The use of biodiesel

This paper evaluates and quantifies the environmental impact from the use of some renewable fuels and fossils fuels in internal combustion engines. The following fuels are evaluated: gasoline blended with anhydrous ethyl alcohol (anhydrous ethanol), conventional diesel fuel, biodiesel in pure form and blended with diesel fuel, and natural gas. For the case of biodiesel, its complete life cycle and the closed carbon cycle (photosynthesis) were considered. The ecological efficiency concept depends on the environmental impact caused by CO(2), SO(2), NO(x) and particulate material (PM) emissions. The exhaust gases from internal combustion engines, in the case of the gasoline (blended with alcohol), biodiesel and biodiesel blended with conventional diesel, are the less polluting; on the other hand, the most polluting are those related to conventional diesel. They can cause serious problems to the environment because of their dangerous components for the human, animal and vegetable life. The resultant pollution of each one of the mentioned fuels are analyzed, considering separately CO(2), SO(2), NO(x) and particulate material (PM) emissions. As conclusion, it is possible to calculate an environmental factor that represents, qualitatively and quantitative, the emissions in internal combustion engines that are mostly used in urban transport. Biodiesel in pure form (B100) and blended with conventional diesel as fuel for engines pollute less than conventional diesel fuel. The ecological efficiency for pure biodiesel (B100) is 86.75%: for biodiesel blended with conventional diesel fuel (B20, 20% biodiesel and 80% diesel), it is 78.79%. Finally, the ecological efficiency for conventional diesel, when used in engines, is 77.34%; for gasoline, it is 82.52%, and for natural gas, it is 91.95%. All these figures considered a thermal efficiency of 30% for the internal combustion engine. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.

Preconcentration and determination of metal ions in commercial ethanol used as fuel for automotive engines

The present investigation reports the synthesis, characterization, and adsorption properties of a new nanomaterial based on organomodified silsesquioxane nanocages. The adsorption isotherms for CuCl,, CoCl2, ZnCl2, NiCl2, and FeCl3 from ethanol solutions were performed by using the batchwise method. The equilibrium condition is reached very quickly (3 min), indicating that the adsorption sites are well exposed. The results obtained in the flow experiments, showed a recovery of ca. 100% of the metal ions adsorbed in a column packed with 2 g of the nanomaterial, using 5 mL of 1.0 mol L-1 HCl solution as eluent. The sorption-desorption of the metal ions made possible the development of a method for preconcentration and determination of metal ions at trace level in commercial ethanol, used as fuel for car engines. The values determined by recommended method for plants 1, 2, and 3 indicated an amount of copper of 51, 60, and 78 mu g L-1, and of iron of 2, 15, and 13 mu g L-1, respectively. These values are very close to those determined by conventional analytical methods. Thus, these similar values demonstrated the accuracy of the determination by recommended method.

TG studies of a composite solid rocket propellant based on HTPB-binder

Thermal decomposition kinetics of solid rocket propellants based on hydroxyl-terminated polybutadiene-HTPB binder was studied by applying the Arrhenius and Flynn-Wall-Ozawa's methods. The thermal decomposition data of the propellant samples were analyzed by thermogravimetric analysis (TG/DTG) at different heating rates in the temperature range of 300-1200 K. TG curves showed that the thermal degradation occurred in three main stages regardless of the plasticizer (DOA) raw material, the partial HTPB/IPDI binder and the total ammonium perchlorate decompositions. The kinetic parameters E-a (activation energy) and A (pre-exponential factor) and the compensation parameter (S-p) were determined. The apparent activation energies obtained from different methods showed a very good agreement.

Object oriented modeling of piston engines

This work reports a conception phase of a piston engine global model. The model objective is forecast the motor performance (power, torque and specific consumption as a function of rotation and environmental conditions). Global model or Zero-dimensional is based on flux balance through each engine component. The resulting differential equations represents a compressive unsteady flow, in which, all dimensional variables are areas or volumes. A review is presented first. The ordinary differential equation system is presented and a Runge-Kutta method is proposed to solve it numerically. The model includes the momentum conservation equation to link the gas dynamics with the engine moving parts rigid body mechanics. As an oriented to objects model the documentation follows the UML standard. A discussion about the class diagrams is presented, relating the classes with physical model related. The OOP approach allows evolution from simple models to most complex ones without total code rewrite. Copyright © 2001 Society of Automotive Engineers, Inc.

A load cell for grain-propelled ballistic rocket thrust measurement

A 1000-kgf resistive strain-gauge load cell has been developed for quality testing of rocket propellant grain. A 7075-T6 aluminum alloy has been used for the elastic column, in which 8 uniaxial, 120-Ω strain gauges have been bonded and connected to form a full Wheatstone bridge to detect the strain. The chosen geometry makes the transducer insensitive to moments and, also, to the temperature. Experimental tests using a universal testing machine to imposed compression force to the load cell have demonstrated that its behavior is linear, with sensitivity of 2.90 μV/kgf ± 0.34%, and negligible hysteresis. The designed force transducer response to a dynamic test has been comparable to that of a commercial load cell. © 2005 IEEE.

Thermodynamic analysis and comparison of downdraft gasifiers integrated with gas turbine, spark and compression ignition engines for distributed power generation

The objective of the present article is to assess and compare the performance of electricity generation systems integrated with downdraft biomass gasifiers for distributed power generation. A model for estimating the electric power generation of internal combustion engines and gas turbines powered by syngas was developed. First, the model determines the syngas composition and the lower heating value; and second, these data are used to evaluate power generation in Otto, Diesel, and Brayton cycles. Four synthesis gas compositions were tested for gasification with: air; pure oxygen; 60% oxygen with 40% steam; and 60% air with 40% steam. The results show a maximum power ratio of 0.567 kWh/Nm(3) for the gas turbine system, 0.647 kWh/Nm(3) for the compression ignition engine, and 0.775 kWh/Nm(3) for the spark-ignition engine while running on synthesis gas which was produced using pure oxygen as gasification agent. When these three systems run on synthesis gas produced using atmospheric air as gasification agent, the maximum power ratios were 0.274 kWh/Nm(3) for the gas turbine system, 0.302 kWh/Nm(3) for CIE, and 0.282 kWh/Nm(3) for SIE. The relationship between power output and synthesis gas flow variations is presented as is the dependence of efficiency on compression ratios. Since the maximum attainable power ratio of CIE is higher than that of SIE for gasification with air, more research should be performed on utilization of synthesis gas in CIE. (C) 2014 Elsevier Ltd. All rights reserved.

Processing and characterization of ablative composites used in rocket motors

The main objective of this research work was to obtain two formulations of ablative composites. These composites are also known as ablative structural composites, for applications in atmospherically severe conditions according to the high-temperature, hot gaseous products flow generated from the burning of solid propellants. The formulations were manufactured with phenolic resin reinforced with chopped carbon fiber. The composites were obtained by the hot compression molding technique. Another purpose of this work was to conduct the physical and chemical characterization of the matrix, the reinforcements and the composites. After the characterization, a nozzle divergent of each formulation was manufactured and its performance was evaluated through the rocket motor static firing test. According to the results found in this work, it was possible to observe through the characterization of the raw materials that phenolic resins showed peculiarities in their properties that differentiate one from the other, but did not exhibit significant differences in performance as a composite material for use in ablation conditions. Both composites showed good performance for use in thermal protection, confirmed by firing static tests (rocket motor). Composites made with phenolic resin and chopped carbon fiber showed that it is a material with excellent resistance to ablation process. This composite can be used to produce nozzle parts with complex geometry or shapes and low manufacturing cost.

O estudo da usinagem em torneamento da superliga à base de níquel Pyromet 31v

The search for materials with higher properties and characteristics (wear resistance, oxidation, corrosion, etc.) has driven research of various materials. Among the materials that are being studied with such properties and characteristics are super alloys based on nickel which has an important role in the aeronautical, automotive, marine, production of gas turbines and now in space vehicles, rocket engineering , experimental aircraft, nuclear reactors, steam-powered plants, petrochemical and many other applications because besides having all the characteristics and properties mentioned above also have an excellent performance at high temperatures. The super alloy based on nickel studied in this work is the super alloy Pyromet 31v normally used in the manufacture of exhaust valves in common engines and diesel engines of high power by cater requirements such as mechanical strength and corrosion resistance at temperatures of approximately 815 ° C. The objective of this work is to produce results to demonstrate more specific information about the real influence of coatings on cutting tools and cutting fluids in turning and thus promote the optimization of the machining of these alloys. The super alloy Pyromet 31v was processed through turning, being performed with various machining parameters such as cutting speed, feed rate, depth in conditions of Minimum Amount of Fluid (MAF), abundant fluid, cutting tools with coating and without coating in early in his work life and with wear. After turning were obtained several samples of chips and the part generated during the machining process, was measured roughness of the material, subsequently made macrostructural analysis of the tools used order to detect possible wear and microstructural analysis of samples collected being that the latter was used for Optical Microscopy, Scanning Electron Microscopy (SEM) and ... (Complete abstract click electronic access below)

Viabilidade da consorciação de pimentão com repolho, rúcula, alface e rabanete

O trabalho foi conduzido na UNESP, Jaboticabal-SP, de setembro/2003 a janeiro/2004, com objetivo de avaliar a viabilidade da consorciação de pimentão com as culturas de repolho, rúcula, alface e rabanete. O experimento constou de 15 tratamentos, correspondentes a 10 cultivos consorciados (combinações das cinco hortaliças) e cinco monocultivos. Utilizou-se o delineamento experimental em blocos casualizados, com seis repetições. Foram utilizados os híbridos Magali R e Kenzan, respectivamente, para pimentão e repolho; e as cultivares Vera, Cultivada e Crimson Gigante, respectivamente, para alface, rúcula e rabanete. As produtividades de pimentão e repolho em cultivo consorciado não diferiram significativamente das obtidas em monocultivo. Maior massa fresca de parte aérea de plantas de alface (438,86 g/planta) foi observada quando a alface foi consorciada com pimentão, diferindo estatisticamente dos demais cultivos que obtiveram em média 323,05 g/planta de alface. Aumento na produtividade de raízes comerciais de rabanete foi observado quando consorciado com pimentão, porém, foi significativamente superior apenas ao cultivo consorciado de pimentão+repolho+rabanete. A massa fresca da parte aérea da rúcula mostrou diferença estatística apenas entre os consórcios de pimentão+rúcula+alface e pimentão+repolho+rúcula. Exceto o consórcio pimentão+repolho que obteve índice de uso eficiente da terra (UET) de 1,92; todos os outros consórcios apresentaram UET superior a 2,0, com maior UET (2,64) obtido no consórcio pimentão+alface. A superioridade de 92 a 164% na produção de alimento por área dos consórcios sobre os monocultivos, demonstra a viabilidade dos policultivos e maior eficiência do uso da terra.

Envelhecimento acelerado de sementes de espécies oleráceas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Viabilidade produtiva e econômica do consórcio entre chicória e rúcula em função da época de plantio

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)