929 resultados para consumption of fuel
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When using appropriate inflation pressures and load capacity (ballast), it may obtain a higher yield and prolongation of the life of the tire, besides it may minimize the problems of loss of traction, increased slippage and fuel consumption. This study aimed to evaluate the fuel consumption of a tractor operating with new and worn tires in three conditions of ballasting and three inflation pressures, when driving on compacted soil with vegetation cover. The experiment was conducted at the experimental unit from the Department of Animal Science, Federal University of Lavras, state of Minas Gerais, Brazil, in an agricultural soil compacted by cattle trampling and with vegetation cover. It was used a tractor 4x2 with front wheel assist, of a 65.62 kW engine power. The tires were of R1 type, diagonal (front: 12.4 to 24; and rear: 18.4 to 30), the average height of the clutches of the new tires were 0.3 and 0.35 m for front and rear tires, respectively, and for the worn tires were 0.018 and 0.0045 m, for the front and the rear tires, respectively. The results showed advantages for the tractor equipped with new tires.
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The fuel consumption is an important factor in the vehicle development due the fact that it has a direct effect on its trade aims. Besides that, it is known that the petrol is a scarce fuel. In this paper it is presented a procedure of fuel consumption calculation for a vehicle traveling in driving schedule. In such calculation it has been taken into account the operational conditions (load, pavement, climbing road, among others) and the building characteristics (map engine, transmission, frontal area, tire, among others) of road vehicles. There has also been an application of the theoretical model developed in a sample Mercedes-Benz do Brasil vehicle which has been compared with the values of experimental tests. Copyright © 1997 Society of Automotive Engineers, Inc.
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Includes bibliography.
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This paper presents the lifecycle assessment (LCA) of fuel ethanol, as 100% of the vehicle fuel, from sugarcane in Brazil. The functional unit is 10,000 km run in an urban area by a car with a 1,600-cm(3) engine running on fuel hydrated ethanol, and the resulting reference flow is 1,000 kg of ethanol. The product system includes agricultural and industrial activities, distribution, cogeneration of electricity and steam, ethanol use during car driving, and industrial by-products recycling to irrigate sugarcane fields. The use of sugarcane by the ethanol agribusiness is one of the foremost financial resources for the economy of the Brazilian rural area, which occupies extensive areas and provides far-reaching potentials for renewable fuel production. But, there are environmental impacts during the fuel ethanol lifecycle, which this paper intents to analyze, including addressing the main activities responsible for such impacts and indicating some suggestions to minimize the impacts. This study is classified as an applied quantitative research, and the technical procedure to achieve the exploratory goal is based on bibliographic revision, documental research, primary data collection, and study cases at sugarcane farms and fuel ethanol industries in the northeast of SA o pound Paulo State, Brazil. The methodological structure for this LCA study is in agreement with the International Standardization Organization, and the method used is the Environmental Design of Industrial Products. The lifecycle impact assessment (LCIA) covers the following emission-related impact categories: global warming, ozone formation, acidification, nutrient enrichment, ecotoxicity, and human toxicity. The results of the fuel ethanol LCI demonstrate that even though alcohol is considered a renewable fuel because it comes from biomass (sugarcane), it uses a high quantity and diversity of nonrenewable resources over its lifecycle. The input of renewable resources is also high mainly because of the water consumption in the industrial phases, due to the sugarcane washing process. During the lifecycle of alcohol, there is a surplus of electric energy due to the cogeneration activity. Another focus point is the quantity of emissions to the atmosphere and the diversity of the substances emitted. Harvesting is the unit process that contributes most to global warming. For photochemical ozone formation, harvesting is also the activity with the strongest contributions due to the burning in harvesting and the emissions from using diesel fuel. The acidification impact potential is mostly due to the NOx emitted by the combustion of ethanol during use, on account of the sulfuric acid use in the industrial process and because of the NOx emitted by the burning in harvesting. The main consequence of the intensive use of fertilizers to the field is the high nutrient enrichment impact potential associated with this activity. The main contributions to the ecotoxicity impact potential come from chemical applications during crop growth. The activity that presents the highest impact potential for human toxicity (HT) via air and via soil is harvesting. Via water, HT potential is high in harvesting due to lubricant use on the machines. The normalization results indicate that nutrient enrichment, acidification, and human toxicity via air and via water are the most significant impact potentials for the lifecycle of fuel ethanol. The fuel ethanol lifecycle contributes negatively to all the impact potentials analyzed: global warming, ozone formation, acidification, nutrient enrichment, ecotoxicity, and human toxicity. Concerning energy consumption, it consumes less energy than its own production largely because of the electricity cogeneration system, but this process is highly dependent on water. The main causes for the biggest impact potential indicated by the normalization is the nutrient application, the burning in harvesting and the use of diesel fuel. The recommendations for the ethanol lifecycle are: harvesting the sugarcane without burning; more environmentally benign agricultural practices; renewable fuel rather than diesel; not washing sugarcane and implementing water recycling systems during the industrial processing; and improving the system of gases emissions control during the use of ethanol in cars, mainly for NOx. Other studies on the fuel ethanol from sugarcane may analyze in more details the social aspects, the biodiversity, and the land use impact.
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This article analysed scenarios for Brazilian consumption of ethanol for the period 2006 to 2012. The results show that if the country`s GDP sustains a 4.6% a year growth, domestic consumption of fuel ethanol could increase to 25.16 billion liters in this period, which is a volume relatively close to the forecasted gasoline consumption of 31 billion liters. At a lower GDP growth of 1.22% a year, gasoline consumption would be reduced and domestic ethanol consumption in Brazil would be no higher than 18.32 billion liters. Contrary to the current situation, forecasts indicated that hydrated ethanol consumption could become much higher than anhydrous consumption in Brazil. The former is being consumed in cars moved exclusively by ethanol and flex-fuel cars, successfully introduced in the country at 2003. Flex cars allow Brazilian consumers to choose between gasoline and hydrated ethanol and immediately switch to whichever fuel presents the most favourable relative price.
Analysis of oxy-fuel combustion as an alternative to combustion with air in metal reheating furnaces
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Using oxygen instead of air in a burning process is at present being widely discussed as an option to reduce CO2 emissions. One of the possibilities is to maintain the combustion reaction at the same energy release level as burning with air, which reduces fuel consumption and the emission rates of CO2. A thermal simulation was made for metal reheating furnaces, which operate at a temperature in the range of 1150-1250 degrees C, using natural gas with a 5% excess of oxygen, maintaining fixed values for pressure and combustion temperature. The theoretical results show that it is possible to reduce the consumption of fuel, and this reduction depends on the amount of heat that can be recovered during the air pre-heating process. The analysis was further conducted by considering the 2012 costs of natural gas and oxygen in Brazil. The use of oxygen showed to be economically viable for large furnaces that operate with conventional heat recovering systems (those that provide pre-heated air at temperatures near 400 degrees C). (C) 2014 Elsevier Ltd. All rights reserved.
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Alternative fuel sources have been extensively studied. Hydrogen gas has gained attention because its combustion releases only water, and it can be produced by microorganisms using organic acids as substrates. The aim of this study was to enrich a microbial consortium of photosynthetic purple non-sulfur bacteria from an Upflow Anaerobic Sludge Blanket reactor (UASB) using malate as carbon source. After the enrichment phase, other carbon sources were tested, such as acetate (30 mmol l(-1)), butyrate (17 mmol l(-1)), citrate (11 mmol l(-1)), lactate (23 mmol l(-1)) and malate (14.5 mmol l(-1)). The reactors were incubated at 30 degrees C under constant illumination by 3 fluorescent lamps (81 mu mol m(-2) s(-1)). The cumulative hydrogen production was 7.8, 9.0, 7.9, 5.6 and 13.9 mmol H-2 l(-1) culture for acetate, butyrate, citrate, lactate and malate, respectively. The maximum hydrogen yield was 0.6, 1.4, 0.7, 0.5 and 0.9 mmol H-2 mmol(-1) substrate for acetate, butyrate, citrate, lactate and malate, respectively. The consumption of substrates was 43% for acetate, 37% for butyrate, 100% for citrate, 49% for lactate and 100% for malate. Approximately 26% of the clones obtained from the Phototrophic Hydrogen-Producing Bacterial Consortium (PHPBC) were similar to Rhodobacter, Rhodospirillum and Rhodopseudomonas, which have been widely cited in studies of photobiological hydrogen production. Clones similar to the genus Sulfurospirillum (29% of the total) were also found in the microbial consortium. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Index of the relative importance of fuel efficiency (IFE) in the motor vehicle market. Final report.
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National Highway Traffic Safety Administration, Office of Research and Development, Washington, D.C.
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Digestate from the anaerobic digestion conversion process is widely used as a farm land fertiliser. This study proposes an alternative use as a source of energy. Dried digestate was pyrolysed and the resulting oil was blended with waste cooking oil and butanol (10, 20 and 30 vol.%). The physical and chemical properties of the pyrolysis oil blends were measured and compared with pure fossil diesel and waste cooking oil. The blends were tested in a multi-cylinder indirect injection compression ignition engine.Engine combustion, exhaust gas emissions and performance parameters were measured and compared with pure fossil diesel operation. The ASTM copper corrosion values for 20% and 30% pyrolysis blends were 2c, compared to 1b for fossil diesel. The kinematic viscosities of the blends at 40 C were 5–7 times higher than that of fossil diesel. Digested pyrolysis oil blends produced lower in-cylinder peak pressures than fossil diesel and waste cooking oil operation. The maximum heat release rates of the blends were approximately 8% higher than with fossil diesel. The ignition delay periods of the blends were higher; pyrolysis oil blends started to combust late and once combustion started burnt quicker than fossil diesel. The total burning duration of the 20% and 30% blends were decreased by 12% and 3% compared to fossil diesel. At full engine load, the brake thermal efficiencies of the blends were decreased by about 3–7% when compared to fossil diesel. The pyrolysis blends gave lower smoke levels; at full engine load, smoke level of the 20% blend was 44% lower than fossil diesel. In comparison to fossil diesel and at full load, the brake specific fuel consumption (wt.) of the 30% and 20% blends were approximately 32% and 15% higher. At full engine load, the CO emission of the 20% and 30% blends were decreased by 39% and 66% with respect to the fossil diesel. Blends CO2 emissions were similar to that of fossil diesel; at full engine load, 30% blend produced approximately 5% higher CO2 emission than fossil diesel. The study concludes that on the basis of short term engine experiment up to 30% blend of pyrolysis oil from digestate of arable crops can be used in a compression ignition engine.
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Background The growing global childhood obesity pandemic has not spared lowincome countries like Malawi, where 8% of children below the age of five years are overweight. Globally, regular consumption of sweetened beverages is implicated among the factors that fuel childhood obesity. Despite the growing problem, there are no local studies on any aspect of sweetened beverage consumption among children in Malawi that could help in guiding interventions and public health nutrition policies. Aim We aimed to assess sweetened beverage consumption among school-going children in Chilinde, a densely populated township in Lilongwe, the capital city of Malawi. Methods A total of 60 school-going children whose caregivers gave verbal consent were included, and a structured questionnaire was administered to the caregiver (or other knowledgeable and responsible member of the household) of each eligible child. Results Our results showed that 50 of the 60 children sampled were consuming a wide-range of sweetened beverages on a regular basis on any day of the week, mostly during meal times (n = 23), before going to school (n = 22), and after school (n = 19). One-third of the children were reportedly consuming up to 300 mL of several sweetened beverages per day. Conclusion Like in many countries around the world, consumption of sweetened beverages appears to be common among young school-going children in this urban setting in Malawi. As the country builds public health responses to the growing problem of non-communicable diseases, early preventive interventions among children should be given priority.
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The aim of this study was to validate the intake of carotenoids, fruits and vegetables estimated by the Food Frequency Questionnaire for Adolescents (FFQA) using the method of triads. Blood samples were collected from 80 elementary school adolescents to assess serum levels of β-carotene. Partial correlation coefficients (r) were calculated between an estimated intake of carotenoids, fruits and vegetables and the serum levels of β-carotene. Validity coefficients were calculated using the method of triads. With the exception of carotenoids, partial r from the food frequency questionnaire (FFQ) were greater than those of the 24-hour recall (24hR). The fruit/vegetable group showed the highest partial r for the FFQ (r = 0.235) and the 24hR (r = 0.137). The highest validity coefficient was obtained for the vegetable group, as assessed by the FFQ (r = 0.873). On average, the validity coefficient values for the FFQ were greater than those obtained for the 24hR or the β-carotene serum levels. The FFQA is an accurate tool for estimating the intake of carotenoids, fruits and vegetables in this population group.
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The present study sought to assess the impact of an intervention to reduce weight and control risk factors of noncommunicable chronic diseases in overweight or obese adults who are users of primary and secondary healthcare units of the public health system of Pelotas, Brazil. We hypothesized that individuals who received an educational intervention regarding how to lose weight and prevent other noncommunicable chronic disease risk factors through nutrition would lose weight and acquire active habits during leisure time more frequently than individuals under regular care. Two hundred forty-one participants from the Nutrition Outpatient Clinic of the Medical Teaching Hospital of the Federal University of Pelotas, Brazil, aged 20 years or older and classified as overweight or obese were randomly allocated to either the intervention group (IG; n = 120) or control group (CG; n = 121). The IG received individualized nutritional care for 6 months, and the CG received individualized usual care of the health services. Intention-to-treat analyses showed that at 6 months, mean fasting glycemia and daily consumption of sweet foods and sodium were reduced, and the time spent on physical leisure activity was increased in IG. Analysis of adherence to the protocol of the study revealed that individuals from IG had lost more in body weight, waist circumference, and fasting glucose compared to the CG. Leisure time physical activity increased in IG. Individuals adhered equally to the dietetic recommendations, irrespective of the nutrition approach that was used
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Our objective in this work was to test the effects of daily intake of bread produced with partially defatted ground flaxseed on the climacteric symptoms and endometrial thickness of postmenopausal women. A double-blind, placebo-controlled, randomized clinical trial was performed with 38 women who had been postmenopausal for 1–10 y and consumed 2 slices of bread containing 25 g of flaxseed (46 mg lignans) or wheat bran (<1 mg lignans; control) every day for 12 consecutive weeks. The outcome variables were the daily number of hot flashes, the Kupperman Menopausal Index (KMI), and endometrial thickness. The plasma lipid profile (total cholesterol and HDL, LDL, and VLDL cholesterol fractions and triglycerides) and the hormones estradiol, follicle-stimulating hormone, thyroid-stimulating hormone, and free thyroxine also were measured. Food intake was evaluated by means of 2 24-h recalls, before and after the treatment. Twenty patients in the study group and 18 in the control group completed the study. The general characteristics did not differ between the 2 groups at the start of the study. Both had significant, but similar, reductions in hot flashes and KMI after 3 mo of treatment. Moreover, endometrial thickness was not affected in either group. Our findings clearly show that although flaxseed is safe, its consumption at this level (46 mg lignans/d) is no more effective than placebo for reducing hot flashes and KMI