A neural approach for determination of global energetic efficiency indicator in groundwater wells

In most of the cases, the systems of water distribution from groundwater wells use electrical submersible pumps. All electrical energy is applied to the pumps; however, other components (pipes, valves, etc.) of these systems are also responsible by the higher or lower consumption of electric energy. The supervisors and operators of the systems should thus have knowledge of the global energetic behavior of the process in order to administrate it properly. This work suggests a 'Global Energetic Efficiency Indicator' for groundwater wells by using mathematical equations and neural networks. Simulation results will be presented in order to demonstrate the validity of the proposed approach.

Conjugated linoleic acid and cardiac health: Oxidative stress and energetic metabolism in standard and sucrose-rich diets

Studies on conjugated linoleic acid ingestion and its effect on cardiac tissue are necessary for the safe utilization of this compound as supplement for weight loss. Male Wistar 24-rats were divided into four groups (n = 6):(C)given standard chow, water and 0.5 ml saline, twice a week by gavage; (C-CLA)receiving standard chow, water and 0.5 ml of conjugated linoleic acid, twice a week, by gavage; (S)given standard chow, saline by gavage, and 30% sucrose in its drinking water; (S-CLA)receiving standard chow, 30% sucrose in its drinking water and conjugated linoleic acid. After 42 days of treatment S rats had obesity with increased abdominal-circumference, dyslipidemia, oxidative stress and myocardial lower citrate synthase(CS) and higher lactate dehydrogenase(LDH) activities than C. Conjugated linoleic acid had no effects on morphometric parameters in C-CLA, as compared to C, but normalized morphometric parameters comparing S-CLA with S. There was a negative correlation between abdominal adiposity and resting metabolic rate. Conjugated linoleic acid effect, enhancing fasting-VO2/surface area, postprandial-carbohydrate oxidation and serum lipid hydroperoxide resembled to that of the S group. Conjugated linoleic acid induced cardiac oxidative stress in both fed conditions, and triacylglycerol accumulation in S-CLA rats. Conjugated linoleic acid depressed myocardial LDH comparing C-CLA with C, and beta-hydroxyacyl-coenzyme-A dehydrogenase/CS ratio, comparing S-CLA with S. In conclusion, dietary conjugated linoleic acid supplementation for weight loss can have long-term effects on cardiac health. Conjugated linoleic acid, isomers c9, t11 and t10, c12 presented undesirable pro-oxidant effect and induced metabolic changes in cardiac tissue. Nevertheless, despite its effect on abdominal adiposity in sucrose-rich diet condition, conjugated linoleic acid may be disadvantageous because it can lead to oxidative stress and dyslipidemic profile. (c) 2007 Elsevier B.V All rights reserved.

Hydrochemistry on a waste disposal area of sand mining activities at Analandia, Sao Paulo State, Brazil, and their implications on the mobilization of uranium

Groundwaters and surface waters from an area of treatment of sand for industrial purposes at Analandia municipality, nearly in the center of Sao Paulo State, Brazil, were chemically and isotopically analyzed with two aims: to evaluate if the anthropogenic activities that has taken place for the last 6 years is affecting the quality of the hydrological resources and to relate the hydrogeochemical behaviour of the uranium isotopes 234U and 238U with the pattern of circulation of groundwaters.

Energetic cost of predation: Aerobic metabolism during prey ingestion by juvenile rattlesnakes, Crotalus durissus

We investigated the cost of prey ingestion in the South American rattlesnake, Crotalus durissus, to see if the capacity to generate energy aerobically could be a constraint on the size of the prey that can be ingested. To accomplish this goal, we measured time and aerobic metabolism (inferred from oxygen consumption) of juvenile C. durissus ingesting prey ranging from 10 to 50% of their own body mass. Time needed for prey ingestion increased with prey size, with prey representing 10 and 20% of snake size being ingested with the same effort. Whole animal rates of oxygen consumption increased linearly with prey size, but at a slower pace for snakes ingesting prey larger than 30% of their body mass. Aerobic factorial power input necessary for prey ingestion increased with prey size, and for snakes ingesting prey representing 50% of their body mass it equaled the aerobic factorial scope for exercise. For the maximum prey size tested, the aerobic derived energy necessary for prey ingestion represented 0.02% of the total energy content of the prey. Within the prey size range we studied, the cost of ingestion did not constitute any constraint on the size of the prey that can be ingested. These constraints are set by morphological (gape size), ecological (predation risk), and, probably, by physiological parameters, as suggested by the tendency of V̇O2 during ingestion to increase at a slower pace at relative larger prey sizes.

Energetic and physiological correlates of prey handling and ingestion in lizards and snakes

In this review, we summarize the energetic and physiological correlates of prey handling and ingestion in lizards and snakes. There were marked differences in the magnitude of aerobic metabolism during prey handling and ingestion between these two groups, although they show a similar pattern of variation as a function of relative prey mass. For lizards, the magnitude of aerobic metabolism during prey handling and ingestion also varied as a function of morphological specializations for a particular habitat, prey type, and behavior. For snakes, interspecific differences in aerobic metabolism during prey handling seem to be correlated with adaptations for prey capture (venom injection vs. constriction). During ingestion by snakes, differences in aerobic metabolism might be due to differences in cranial morphology, although allometric effects might be a potentially confounded effect. Anaerobic metabolism is used for prey handling and ingestion, but its relative contribution to total ATP production seems to be more pronounced in snakes than in lizards. The energetic costs of prey handling and ingestion are trivial for both groups and cannot be used to predict patterns of prey-size selection. For lizards, it seems that morphological and ecological factors set the constraints on prey handling and ingestion. For snakes, besides these two factors, the capacity of the cardio-respiratory system may also be an important factor constraining the capacity for prey handling and ingestion. © 2001 Elsevier B.V.

Study of a hybrid solid oxide fuel cell: Energetic analysis and sankey diagram

In this paper a hybrid solid oxide fuel cell (SOFC) system is analyzed. This system applies a combined cycle utilizing gas turbine associated to a SOFC for rational decentralized energy production. Initially the relative concepts about the fuel cell are presented, followed by some chemical and technical informations such as the change of Gibbs free energy in isothermal fuel oxidation (or combustion) directly into electricity. This represents a very high fraction of the lower heating value (LHV) of a hydrocarbon fuel. In the next step a methodology for the study of SOFC associated with a gas turbine system is developed, considering the electricity and steam production for a hospital, as regard to the Brazilian conditions. This methodology is applied to energetic analysis. Natural gas is considered as a fuel. In conclusion, it is shown by a Sankey Diagram that the hybrid SOFC system may be an excellent opportunity to strengthen the decentralized energy production in Brazil. It is necessary to consider that the cogeneration in this version also is a sensible alternative from the technical point of view, demanding special methods of design, equipment selection and mainly of the contractual deals associated to electricity and fuel supply.

Windrowing and prismatic baling of sugar cane vegetal residues: Some operational parameters and energetic efficiency

It was evaluated the energetic efficiency and operational parameters of a windrowing and prismatic baling, both from CASE NEW HOLLAND® operations in sugarcane vegetal residues (green leaves, dry leaves and tops) picked mechanically in green cane. The area belongs to COSTA PINTO MILL (COSAN® Group) which was harvested mechanically by combines in the State of Sao Paulo, Brazil. The geographic location of the area is: Latitude 22°40'30S, Longitude 47°36'38W and Altitude of 605m. The variety was RB 82-5336, planted in 1.40m row spacing, with 78t.ha-1 yield. The vegetal residues analysis obtained 69.93% of leaves, 21.44% of stalks fractions, 2.27% of tops and 6.36% of total strange matter. The vegetal residues values were: gross heat of 18.43MJ.kg-1, low heat of 17.00MJ.kg'1 and useful heat of 12.94MJ.kg-1. The vegetal residues average energetic potential was 342.48GJ.ha-1. The treatments were simple, double and triple windrowing. The use of the rake and prismatic baler to pick up the residues was viable. The simple windrowing treatment presented the best results: effective capacity of 83.06t.ha-1, fuel consumption of 0.18L.t -1 and 99.95% of positive energetic efficiency. The bales obtained in the treatment of triple windrowing presented the largest specific mass average of 221.11kg.m-3. The soil amount in the bales increased with successive windrowing. The baling operation in the triple windrowing treatment obtained better results, presenting the effective capacities of 20.29t.h -1 and 1.45ha.h-1 and fuel consumption of for baled in 1.37L.t-1. The high total energetic efficiency of 99.53% indicates that is technically viable the withdrawal of the vegetal residues.

Windrowing and cylindrical baling of sugar cane vegetal residues: Some operational parameters and energetic efficiency

The objective of this study was to analyze the sugar cane vegetal residues collection, as well as determining its energetic potential, using a rake and cylindrical baler, both from NEW HOLLAND® under two different windrowing process (simple and double). The field tests were carried out in an area that belongs to COSTA PINTO MILL (COSAN® Group) in the city of Piracicaba, Sao Paulo State, Brazil. The geographic location of the area is: Latitude 22°4030'S, Longitude 47°3633'W and altitude of 605m. From the trash analysis, before the baling, the following average results were obtained: 69.93% of leaves; 2.27% of stalks fractions; 21.44% of tops and 6.36% of total strange matter. The estimated residues yield was 27.01 tons.ha -1 with a gross heat of 18.43 MJ.kg-1, low heat of 17.01 MJ.kg-1, useful heat of 13.32 MJ.kg-1, average moisture of 20.76% and an energetic potential of 494,875.09 MJ.ha-1. In the windrowing operations (simple and double) the averages of the 5 out of 13 analyzed variable presented differences between them in a 1% level of significance in the Tukey Test. The averages comparison of the results for bale's specific mass and the effective capacities (ton.h-1) e (ha.h-1) had been significant at a 5% level in the Tukey Test. The comparisons of the averages for the results had been significant to 1% level. The strange matter averages of the bales did not differed between them.

The energetic cost of maintenance in ruminants: From classical to new concepts and prediction systems

The cost of maintenance makes up a large part of total energy costs in ruminants. Metabolizable energy (ME) requirement for maintenance (MEm) is the daily ME intake that exactly balances heat energy (HE). The net energy requirement for maintenance (NEm) is estimated subtracting MEm from the HE produced by the processing of the diet. Men cannot be directly measured experimentally and is estimated by measuring basal metabolism in fasted animals or by regression measuring the recovered energy in fed animals. MEm and NEm usually, but not always, are expressed in terms of BW0.75. However, this scaling factor is substantially empirical and its exponent is often inadequate, especially for growing animals. MEm estimated by different feeding systems (AFRC, CNCPS, CSIRO, INRA, NRC) were compared by using dairy cattle data. The comparison showed that these systems differ in the approaches used to estimate MEm and for its quantification. The CSIRO system estimated the highest MEm, mostly because it includes a correction factor to increase ME as the feeding level increases. Relative to CSIRO estimates, those of NRC, INRA, CNCPS, and AFRC were on average 0.92, 0.86, 0.84, and 0.78, respectively. MEm is affected by the previous nutritional history of the animals. This phenomenon is best predicted by dynamic models, of which several have been published in the last decades. They are based either on energy flows or on nutrient flows. Some of the different approaches used were described and discussed.

Energetic, ecologic and fluid-dynamic analysis of a fluidized bed gasifier operating with sugar cane bagasse

This work aims to study the thermodynamic, ecological and fluid-dynamic aspects of a circulating fluidized bed gasifier using sugar cane bagasse as biomass, in order to estimate a model of its normal operation. In the initial stage was analysed the composition of biomass selected (sugar cane bagasse) and its lower heating value (LHV) was calculated. The energy balance of the gasifier was done, being the volumetric flow of air, synthesis gas and biomass estimated. Also the power produced by this gasifier was theoretically estimated. Then the circulating fluidized bed gasifier was designed for operation with approximately 100 kg/h of processed biomass. Cross-sectional area of the reactor, feeder size, diameter of the exit zone of the gases and minimum height of the expanded bed were selected. Some bed gasifier hydrodynamic factors were also studied. The minimum fluidization velocity, fluidization terminal velocity, and average fluidizing velocity were calculated, in order to understand the fluid-dynamic behaviour of gasification of this fuel. It was obtained a theoretical model that can support a possible prototype of circulating fluidized bed gasifier biomass. Finally, there were studied the ecological aspects of the gasifier, through an overall methodology. Ecological efficiencies were estimated for two scenarios: first considering the carbon cycle and thereafter disregarding the carbon cycle. In both cases, it can be proved the ecological viability of the project. © 2013 Elsevier Ltd. All rights reserved.

Desempenho operacional de um subsolador de hastes com curvatura lateral (“Paraplow”), em função de diferentes velocidades de deslocamento e profundidades de trabalho

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Mecanismos sulcadores de semeadora-adubadora na cultura do milho (Zea mays L.) no sistema de plantio direto

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Desempenho operacional de máquinas agrícolas na implantação da cultura do sorgo forrageiro

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Energetic efficiency of an agricultural tractor in function of tire inflation pressure

The tire inflation pressure, among other factors, determines the efficiency in which a tractor can exert traction. It was studied the effect of using two tire inflation pressures, 110.4 kPa in the front and rear wheels, 124.2 kPa in the front wheel and 138 kPa in the rear wheels, the energetic efficiency of an agricultural tractor of 147 kW of engine power, in the displacement speed of 6.0 km.h-1, on track with firm surface, with the tractor engine speed of 2000 rpm. For each condition of the tire pressure, the tested tractor was subjected to constant forces in the drawbar of 45 kN and 50 kN, covering 30 meters. It was used a randomized complete block with a 2x2 factorial arrangement (tire pressure and drawbar power) with four replications, totaling 16 experimental units. Data were subjected to analysis of variance, using the Tukey test at 5% probability for comparison averages. The lowest hourly and specific fuel consumption, the lowest slippage of the wheelsets and the highest efficiency in the drawbar was obtained with the tire inflation pressure of 110.4 kPa in the front and rear tires of the tractor, highlighting that lower pressures improve energetic and operational performance of the tractor.