oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Dynamics of viscous coalescing droplets in a saturated vapor phase  [PDF]
Lina Baroudi,Sidney R. Nagel,Jeffrey F. Morris,Taehun Lee
Physics , 2015,
Abstract: The dynamics of two liquid droplets coalescing in their saturated vapor phase are investigated by Lattice Boltzmann numerical simulations. Attention is paid to the effect of the vapor phase on the formation and growth dynamics of the liquid bridge in the viscous regime. We observe that the onset of the coalescence occurs earlier and the expansion of the bridge initially proceeds faster when the coalescence takes place in a saturated vapor compared to the coalescence in a non-condensable gas. We argue that the initially faster evolution of the coalescence in the saturated vapor is caused by the vapor transport through condensation during the early stages of the coalescence.
EFFECT OF HIGH MOLECULAR PARAFFINS ON THE EXPLOITATION PROPERTIES OF MOTOR FUELS
Dobromir Ivanov Yordanov,Stoyanka Petkova Petkova,Petko Stoyanov Petkov
Petroleum and Coal , 2007,
Abstract: The isomerization of paraffin with different molecular mass has been studied and the reaction products have been tested as components for motor gasoline and diesel fuels. It has been shown that the isomerization reaction carried out at lower temperatures (300-400K) results in the formation of isomers, which has a greater impact on the performance characteristics of motor fuels.
New technologies in the production of motor fuels from renewable materials  [PDF]
Adna?evi? Borivoj K.
Thermal Science , 2012, DOI: 10.2298/tsci120131063a
Abstract: This work presents resources of the Autonomous Province of Vojvodina available for bioethanol and motor fuels (gasoline and diesel fuel) from sustainable resources: corn-stalks, straw, sweet sorghum, pork fat. The physicochemical basis for novel processes for motor fuel production is coupling microwave pyrolysis of oil shale and catalytic cracking of purified pyrolysis oil, hydrothermal liquefaction of algae and swine manure. The effects of the degree of purification of crude pyrolysis oil and oil shale on the degree of their conversion to gasoline and diesel fuel, as well as the product distribution are investigated. The effects of the duration and temperature of hydrothermal liquefaction of microalga, Botryoccocus braunii, and swine manure on their degrees of conversion into bio-oil and its thermal properties are investigated. The development of novel strategy of biofuel in the Autonomous Province of Vojvodina is presented.
ВПЛИВ ДОМ ШОК НА ТИСК НАСИЧЕНО ПАРИ ВУГЛЕВОДНЕВИХ СЕРЕДОВИЩ The influence of impurities on the saturated vapor pressure hydrocarbon media Влияние примесей на давление насыщенного пара углеводородных сред  [cached]
М.Б. Степанов,?.В. Дрогобицька,В.М. Ледовських
Proceedings of National Aviation University , 2009,
Abstract: Наведено експериментальн результати досл джень впливу нелетких дом шок на тиск насичено пари вуглеводневих середовищ. Показано, що за х наявност спостер га ться позитивне в дхилення в д деального стану, п дпорядкованого закону Рауля. Законом рне зменшення величини позитивного в дхилення тиску насичено пари в д закону Рауля в посл довност вуглеводн в С6Н14 – С13Н28 –С16Н34, можна пояснити зб льшенням енерг дисперс йно м жмолекулярно вза мод з зростанням молекулярно маси та здатн стю молекул до поляризац . Here are presented experimental result due to the research of the impact non – volatile admixture on the pressure of saturated steam of Hydrocarbonic medium. It is showed, that in their presence is watched the positive deflection from ideal state due to the Raul's low. Also is watched an appropriate decrease of the quantity of positive deflection of saturated steam from Raul's law in Hydrocarbonic consequence C-6H14 - C13H28 – C16H34,, which could be explained by increasing of depressive intermolecula cooperation energy with increasing of molecule's possibility to polarize. Приведены экспериментальные результаты исследований влияния нелетучих примесей на давление насыщенного пара углеводородных сред. Показано, что при их наличии наблюдается положительное отклонение от идеального состояния, подчиненного закону Рауля. Закономерное уменьшение величины положительного отклонения давления насыщенного пара от закона Рауля в последовательности углеводородов С6Н14 - С13Н28-С16Н34, можно объяснить увеличением энергии дисперсионной межмолекулярного взаимодействия с ростом молекулярной массы и способностью молекул к поляризации.
Formate Formation and Formate Conversion in Biological Fuels Production  [PDF]
Bryan R. Crable,Caroline M. Plugge,Michael J. McInerney,Alfons J. M. Stams
Enzyme Research , 2011, DOI: 10.4061/2011/532536
Abstract: Biomethanation is a mature technology for fuel production. Fourth generation biofuels research will focus on sequestering CO2 and providing carbon-neutral or carbon-negative strategies to cope with dwindling fossil fuel supplies and environmental impact. Formate is an important intermediate in the methanogenic breakdown of complex organic material and serves as an important precursor for biological fuels production in the form of methane, hydrogen, and potentially methanol. Formate is produced by either CoA-dependent cleavage of pyruvate or enzymatic reduction of CO2 in an NADH- or ferredoxin-dependent manner. Formate is consumed through oxidation to CO2 and H2 or can be further reduced via the Wood-Ljungdahl pathway for carbon fixation or industrially for the production of methanol. Here, we review the enzymes involved in the interconversion of formate and discuss potential applications for biofuels production. 1. Introduction Methane has been recognized as an important fuel source since at least 1778 when Alessandro Volta first identified methane as the primary component of swamp gas.In 1884 Louis Pasteur proposed using methane produced from the anaerobic decay of horse dung to light the streets of Paris. Naturally occurring methane, otherwise known as natural gas, currently provides approximately 20–25% of the US energy demand. The United States’ 2010 methane consumption was estimated to be approximately 2 . 4 3 × 1 0 1 6 ?kJ and demand is anticipated to grow at an annualized rate of 0.4% annually through 2035 to 2 . 7 4 × 1 0 1 6 ?kJ [1]. Current government support and investment underscores the important role of biomethanation. Several countries, including Japan, the United States, and Sweden, have taken leadership roles in designing the next generation of methane-fueled vehicles [2]. As of 2006, Germany had invested in nearly 3500 biogas production facilities that provided approximately 900?MW of electricity [3]. Denmark and Sweden have made similar investments into biogas production facilities and biomethanation will be one of many tools the Dutch dairy industry relies on to achieve energy self-sufficiency by 2020 [4]. Biomethanation is a complex biological process. It is well established that methanogenic ecosystems require multipart cooperation between at least three trophic guilds. This includes fermentative bacteria, acetogenic bacteria, and methanogens. In short, complex organic molecules are fermented to acetate, hydrogen, formate, and a variety of organic acids (lactate, propionate, and butyrate) and ethanol. Acetogenic bacteria convert
Vapor Pressure of Saturated Aqueous Solutions of Potassium Sulfate from 310?K to 345?K  [PDF]
Matias O. Maggiolo,Francisco J. Passamonti,Abel C. Chialvo
Journal of Thermodynamics , 2011, DOI: 10.1155/2011/432132
Abstract: The experimental evaluation of the vapor pressure of saturated aqueous solutions of potassium sulfate was carried out in the range of temperatures 310K≤≤345K. The experimental data were used to determine the corresponding values of the water activity in such solutions. The analytical expressions as a function of temperature of both, vapor pressure and water activity, were obtained from the correlation of the experimental results. The vapor pressure expression was also extrapolated to a different temperature range in order to make a comparison with the results obtained by other authors.
Vapor Pressure of Saturated Aqueous Solutions of Potassium Sulfate from 310?K to 345?K  [PDF]
Matias O. Maggiolo,Francisco J. Passamonti,Abel C. Chialvo
Journal of Thermodynamics , 2011, DOI: 10.1155/2011/432132
Abstract: The experimental evaluation of the vapor pressure of saturated aqueous solutions of potassium sulfate was carried out in the range of temperatures . The experimental data were used to determine the corresponding values of the water activity in such solutions. The analytical expressions as a function of temperature of both, vapor pressure and water activity, were obtained from the correlation of the experimental results. The vapor pressure expression was also extrapolated to a different temperature range in order to make a comparison with the results obtained by other authors. 1. Introduction The dependence on temperature of the vapor pressure of saturated aqueous solutions has been already determined for most of the inorganic salts, particularly halides, sulfates, and nitrates [1–3]. However, for the case of potassium sulfate the available information is surprisingly scarce and restricted to the temperature range [4–7] plus one evaluation at 374?K [8]. On this context, the present work studied experimentally the vapor pressure of saturated aqueous solutions of potassium sulfate from 310?K to 345?K and evaluated from these data the dependence of the water activity on temperature. For this purpose, an isothermal static apparatus has been constructed and the reliability of the methodology employed was verified through the determination of the vapor pressure of pure water. 2. Experimental Section 2.1. Equipment The apparatus used for the vapor pressure measurements, which is a modified version of the device employed by Kim et al. [9], is shown in Figure 1. It consists of a round-bottom flask (A) of 125?cm3 which contains the solution to be evaluated. It is connected to a U-tube mercury manometer (F) and to a vacuum pump (H) through the valve (G). The flask, the manometer, and the connecting tubes are immersed in an isothermal water bath (B), which temperature is controlled by a Lauda Thermostat UB20 Ultra (E), thermostated to within ±0.01?K. To ensure the uniformity of the bath temperature, a recirculation pump (D) was used with a flow rate of 4?dm3?min?1. Moreover, a magnetic stirrer (C) was used in order to ensure the highest mass transfer rate between the liquid and vapor phases and also the temperature uniformity inside the equilibration flask. The temperature was measured by a digital thermometer Lauda R46, with a Pt resistance of 100?Ω which precision is ±0.01?K. The pressure was measured by an open U-tube mercury manometer and the manometric readings were made with a cathetometer to ±0.1?mm (±0.015?kPa). The reading performed at the temperature of
Calculation of the Dimer Equilibrium Constant of Heavy Water Saturated Vapor  [PDF]
L. A. Bulavin,S. V. Khrapatiy,V. N. Makhlaichuk
Physics , 2015,
Abstract: Water is the most common substance on Earth.The discovery of heavy water and its further study have shown that the change of hydrogen for deuterium leads to the significant differences in their properties.The triple point temperature of heavy water is higher,at the same time the critical temperature is lower.Experimental values of the second virial coefficient of the EOS for the vapor of normal and heavy water differ at all temperatures.This fact can influence the values of the dimerization constant for the heavy water vapor.The equilibrium properties of the dimerization process are described with the methods of chemical thermodynamics.The chemical potentials for monomers (m) and dimers (d)are the functions of their concentrations.The interactions of monomer-dimer and dimer-dimer types are taken into account within the solution of equation for chemical potentials.The obtained expression for the dimerization constant contains the contributions of these types.The averaged potentials are modeled by the Sutherland potential.Theoretical values of the dimerization constant for the heavy water vapor at different temperatures are compared to those for normal water.We see the exceeding of the values for the heavy water at all temperatures.This fact is in good agreement with all experimental data that is available.The excess is related to the differences in the character of the heat excitations of the dimers of normal and heavy water,their rotational constants and energy of their vibrational excitations.Significant role is also played by the monomer-dimer and dimer-dimer interactions.
Effect of unsaturated fatty acid esters of biodiesel fuels on combustion, performance and emission characteristics of a DI diesel engine  [PDF]
A. Gopinath, Sukumar Puhan, G. Nagarajan
International Journal of Energy and Environment , 2010,
Abstract: Many studies have reported that exhaust from biodiesel fuel gives higher oxides of nitrogen or lower, while HC and smoke emissions are significantly lower than that of diesel fuel. Possible explanations are: the physical properties and fatty acid composition of biodiesel affecting the spray and the mixture formation with reduced heat losses. The aim of this present investigation is to study the effect of unsaturated fatty acid composition of biodiesel on combustion, performance and emissions characteristics of a diesel engine. For this experiment thirteen different biodiesel fuels with different fatty acid compositions were selected. The performance and emissions tests on a single cylinder DI diesel engine were conducted using same biodiesel fuels. The results showed that biodiesel having more unsaturated fatty acids emit more oxides of nitrogen and exhibit lower thermal efficiency compared to biodiesel having more saturated acids. No significant differences in HC and smoke emissions among the biodiesel fuels were noticed. Thermal efficiency and NOX emission of saturated biodiesel is comparatively better than other biodiesel. Combustion analysis results show that high unsaturated fatty acid biodiesel has longer premixed combustion and high peak pressure compared to that of high saturated fatty acid biodiesel.
ВПЛИВ НГ Б ТОР В НА КОРОЗ ЙНУ АГРЕСИВН СТЬ ПАЛИВ, ЩО М СТЯТЬ ОКСИГЕНАТИ Inhibitors on fuels corrosivity, containing oxygenates Влияние ингибиторов на коррозионную агрессивность топлива, содержащих оксигенаты  [cached]
О.Б. Шевченко,Ю.М. Гулямов
Proceedings of National Aviation University , 2006,
Abstract: Подано результати п дбору нг б тор в для палив, що м стять спирти. Розглянуто ефективну сум ш з трьох компонент в комб новано д . Results of inhibitor selection for fuels containing spirits aresubmitted. The effective composition from 3 components of combined action is developed. Представлены результаты подбора ингибиторов для топлив, содержащих спирты. Рассмотрен эффективный состав из трех компонентов комбинированного действия.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.