870 resultados para traffic fuel
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National Highway Traffic Safety Administration, Office of Research and Development, Washington, D.C.
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National Highway Traffic Safety Administration, Office of Research and Development, Washington, D.C.
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Includes bibliographical references.
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"January 1986."
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National Highway Traffic Safety Administration, Office of Research and Development, Washington, D.C.
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A tanulmány azt a kérdést vizsgálja, hogy versenyeznek-e az európai kormányok gázolajra vonatkozó jövedékiadó-kulcsaikkal a nagyobb adóbevételekért, és ha igen, befolyásolja-e az országok mérete kormányaik adóztatási stratégiáját. Az üzemanyagturizmussal szembesülő kormányok adókivetési magatartását egy kétországos adóverseny modellel jelezzük előre, amelyben a standard modellektől eltérően a fogyasztók kereslete árrugalmas. Megmutatjuk, hogy ha a kereslet nem teljesen rugalmatlan, mint Nielsen [2001], illetve Kanbur-Keen [1993] modelljeiben, akkor a nagy ország kormányának egyensúlyi viselkedése nemcsak abban különbözik a kicsiétől, hogy nagyobb adót állapít meg, hanem abban is, hogy válaszfüggvénye meredekebb. Az aszimmetrikus adóverseny általunk használt modelljét a dízelüzemanyagoknak 16 európai ország 1978 és 2005 közötti jövedékiadó-adatain vizsgáljuk. Az 1995 és 2005 közötti időszakra vonatkozó becslési eredményeink megerősítik, hogy az európai országok szomszédaik adókulcs-változtatásának hatására változtattak saját adókulcsaikon, és hogy a területileg/gazdaságilag kisebb országok kisebb intenzitással reagáltak szomszédaik adóváltoztatásra, mint a nagyobbak. Tanulmányunk ezzel magyarázatot nyújt arra is, hogy miért erősödött fel a tagállamok jövedéki adókulcsainak méret szerinti differenciálódása az elmúlt bő tíz évben, valamint hogy miért nem sikerült az Európai Uniónak a minimumadószintre vonatkozó előírásával előbbre lépnie az egységes adóztatás megvalósításában. / === / The paper assesses spatial competition in diesel taxation among European governments. By adding an extension to the standard model, it is shown that asymmetric competition – small countries undercutting large – implies that small countries respond less strongly to tax changes by their neighbours than large countries do. An estimate is then made of the fiscal reaction functions for national governments, employing a first-difference regression model with a weighting scheme constructed from road-traffic density data at national borders. Data from 16 countries (EU-15 minus Greece plus Norway and Switzerland) between 1978 and 2005 provides evidence that European governments set their diesel tax interdependently, and moreover, that small European countries tend to react less strongly to changes in their competitors' tax rate than large countries do.
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This paper proposes an en route speed reduction to complement current ground delay practices in air traffic flow management. Given a nominal cruise speed, there exists a bounded range of speeds that allows aircraft to fly slower with the same or lower fuel consumption than the nominal flight. Therefore, flight times are increased and delay can be partially performed in the air, at no extra fuel cost for the operator. This concept has been analyzed in an initial feasibility study, computing the maximum amount of delay that can be performed in the air in some representative flights. The impact on fuel consumption has been analyzed, and two scenarios are proposed: the flight fuel remains the same as in the nominal flight, and some extra fuel allowance is permitted in order to face uncertainties. Results show significant values of airborne delay that may be useful in many situations, with the exception of short hauls where airborne delay may be too short. If cruise altitude is changed, the amount of airborne delay increases, since changes in cruise speed modify the optimal flight altitudes. From the analyzed flights, a linear dependency is found relating the airborne delay with the amount of extra fuel allowance.
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The results of a study which evaluates the Iowa Motor Vehicle Fuel Reduction Program have been summarized and described in this report. The Iowa Motor Vehicle Fuel Reduction Program was designed to demonstrate fuel savings through traffic signal modernization projects and provide direct benefits to motorists in Iowa.
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This report documents the results of a three million dollar traffic signal improvement demonstration program, known as the Iowa Motor Vehicle Fuel Reduction Program (the program). The program was funded with the use of oil overcharge funds and administered by the Iowa Departments of Natural Resources and Transportation. The objective of the program was to provide restitution to overcharged motorists by improving the efficiency of traffic signals. More efficient traffic signals reduce fuel consumption, delay, travel time, and automobile pollution while improving traffic safety. The program demonstrated the effectiveness of improving traffic signals and resulted in a 14.20-to-1 benefit-to-cost ratio.
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Urbanization has occasionally been linked to negative consequences. Traffic light system in urban arterial networks plays an essential role to the operation of transport systems. The availability of new Intelligent Transportation System innovations paved the way for connecting vehicles and road infrastructure. GLOSA, or the Green Light Optimal Speed Advisory, is a recent integration of vehicle-to-everything (v2x) technology. This thesis emphasized GLOSA system's potential as a tool for addressing traffic signal optimization. GLOSA serves as an advisory to drivers, informing them of the speed they must maintain to reduce waiting time. The considered study area in this thesis is the Via Aurelio Saffi – Via Emilia Ponente corridor in the Metropolitan City of Bologna which has several signalized intersections. Several simulation runs were performed in SUMOPy software on each peak-hour period (morning and afternoon) using recent actual traffic count data. GLOSA devices were placed on a 300m GLOSA distance. Considering the morning peak-hour, GLOSA outperformed the actuated traffic signal control, which is the baseline scenario, in terms of average waiting time, average speed, average fuel consumption per vehicle and average CO2 emissions. A remarkable 97% reduction on both fuel consumption and CO2 emissions were obtained. The average speed of vehicles running through the simulation was increased as well by 7% and a time saved of 25%. Same results were obtained for the afternoon peak hour with a decrease of 98% on both fuel consumption and CO2 emissions, 20% decrease on average waiting time, and an increase of 2% in average speed. In addition to previously mentioned benefits of GLOSA, a 15% and 13% decrease in time loss were obtained during morning and afternoon peak-hour, respectively. Towards the goal of sustainability, GLOSA shows a promising result of significantly lowering fuel consumption and CO2 emissions per vehicle.
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Groundnut shell (GS), after separation of pod, is readily available as a potential feedstock for production of fermentable sugars. The substrate was delignified with sodium sulfite. The delignified substrate released 670 mg/g of sugars after enzymatic hydrolysis (50 degrees C, 120 rpm, 50 hrs) using commercial cellulases (Dyadic Xylanase PLUS, Dyadic Inc. USA). The groundnut shell enzymatic hydrolysate (45.6 g/L reducing sugars) was fermented for ethanol production with free and sorghum stalks immobilized cells of Pichia stipitis NCIM 3498 under submerged cultivation conditions. Immobilization of yeast cells on sorghum stalks were confirmed by scanning electron microscopy (SEM). A maximum of ethanol production (17.83 g/L, yield 0.44 g/g and 20.45 g/L, yield 0.47 g/g) was observed with free and immobilized cells of P. stipitis respectively in batch fermentation conditions. Recycling of immobilized cells showed a stable ethanol production (20.45 g/L, yield 0.47 g/g) up to 5 batches followed by a gradual downfall in subsequent cycles.
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BACKGROUND: Ambient levels of air pollution may affect the health of children, as indicated by studies of infant and perinatal mortality. Scientific evidence has also correlated low birth weight and preterm birth, which are important determinants of perinatal death, with air pollution. However, most of these studies used ambient concentrations measured at monitoring sites, which may not consider differential exposure to pollutants found at elevated concentrations near heavy-traffic roadways. OBJECTIVES: Our goal was to examine the association between traffic-related pollution and perinatal mortality. METHODS: We used the information collected for a case-control study conducted in 14 districts in the City of Sao Paulo, Brazil, regarding risk factors for perinatal deaths. We geocoded the residential addresses of cases (fetal and early neonatal deaths) and controls (children who survived the 28th day of life) and calculated a distance-weighted traffic density (DWTD) measure considering all roads contained in a buffer surrounding these homes. RESULTS: Logistic regression revealed a gradient of increasing risk of early neonatal death with higher exposure to traffic-related air pollution. Mothers exposed to the highest quartile of the DWTD compared with those less exposed exhibited approximately 50% increased risk (adjusted odds ratio = 1.47; 95% confidence interval, 0.67-3.19). Associations for fetal mortality were less consistent. CONCLUSIONS: These results suggest that motor vehicle exhaust exposures may be a risk factor for perinatal mortality.
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Background: Extracellular vesicles in yeast cells are involved in the molecular traffic across the cell wall. In yeast pathogens, these vesicles have been implicated in the transport of proteins, lipids, polysaccharide and pigments to the extracellular space. Cellular pathways required for the biogenesis of yeast extracellular vesicles are largely unknown. Methodology/Principal Findings: We characterized extracellular vesicle production in wild type (WT) and mutant strains of the model yeast Saccharomyces cerevisiae using transmission electron microscopy in combination with light scattering analysis, lipid extraction and proteomics. WT cells and mutants with defective expression of Sec4p, a secretory vesicle-associated Rab GTPase essential for Golgi-derived exocytosis, or Snf7p, which is involved in multivesicular body (MVB) formation, were analyzed in parallel. Bilayered vesicles with diameters at the 100-300 nm range were found in extracellular fractions from yeast cultures. Proteomic analysis of vesicular fractions from the cells aforementioned and additional mutants with defects in conventional secretion pathways (sec1-1, fusion of Golgi-derived exocytic vesicles with the plasma membrane; bos1-1, vesicle targeting to the Golgi complex) or MVB functionality (vps23, late endosomal trafficking) revealed a complex and interrelated protein collection. Semi-quantitative analysis of protein abundance revealed that mutations in both MVB- and Golgi-derived pathways affected the composition of yeast extracellular vesicles, but none abrogated vesicle production. Lipid analysis revealed that mutants with defects in Golgi-related components of the secretory pathway had slower vesicle release kinetics, as inferred from intracellular accumulation of sterols and reduced detection of these lipids in vesicle fractions in comparison with WT cells. Conclusions/Significance: Our results suggest that both conventional and unconventional pathways of secretion are required for biogenesis of extracellular vesicles, which demonstrate the complexity of this process in the biology of yeast cells.
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Oscillatory kinetics is commonly observed in the electrocatalytic oxidation of most species that can be used in fuel cell devices. Examples include formic acid, methanol, ethanol, ethylene glycol, and hydrogen/carbon monoxide mixtures, and most papers refer to half-cell experiments. We report in this paper the experimental investigation of the oscillatory dynamics in a proton exchange membrane (PEM) fuel cell at 30 degrees C. The system consists of a Pt/C cathode fed with oxygen and a PtRu (1:1)/C anode fed with H(2) mixed with 100 ppm of CO, and was studied at different cell currents and anode flow rates. Many different states including periodic and nonperiodic series were observed as a function of the cell current and the H(2)/CO flow rate. In general, aperiodic/chaotic states were favored at high currents and low flow rates. The dynamics was further characterized in terms of the relationship between the oscillation amplitude and the subsequent time required for the anode to get poisoned by carbon monoxide. Results are discussed in terms of the mechanistic aspects of the carbon monoxide adsorption and oxidation. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3463725] All rights reserved.
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The objective of this study is to graft the Surface of carbon black, by chemically introducing polymeric chains (Nafion (R) like) with proton-conducting properties. This procedure aims for a better interaction of the proton-conducting phase with the metallic catalyst particles, as well as hinders posterior support particle agglomeration. Also loss of active surface call be prevented. The proton conduction between the active electrocatalyst site and the Nafion (R) ionomer membrane should be enhanced, thus diminishing the ohmic drop ill the polymer electrolyte membrane fuel cell (PEMFC). PtRu nanoparticles were supported on different carbon materials by the impregnation method and direct reduction with ethylene glycol and characterized using amongst others FTIR, XRD and TEM. The screen printing technique was used to produce membrane electrode assemblies (MEA) for single cell tests in H(2)/air(PEMFC) and methanol operation (DMFC). In the PEMFC experiments, PtRu supported on grafted carbon shows 550 mW cm(-2) gmetal(-1) power density, which represents at least 78% improvement in performance, compared to the power density of commercial PtRu/C ETEK. The DMFC results of the grafted electrocatalyst achieve around 100% improvement. The polarization Curves results clearly show that the main Cause of the observed effect is the reduction in ohmic drop, caused by the grafted polymer. (C) 2009 Elsevier B.V. All rights reserved.