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Gas Consumption (gas + consumption)
Selected AbstractsCuffed endotracheal tubes in children reduce sevoflurane and medical gas consumption and related costsACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2010S. ESCHERTZHUBER Background: This study aims to evaluate sevoflurane and anaesthetic gas consumption using uncuffed vs. cuffed endotracheal tubes (ETT) in paediatric surgical patients. Methods: Uncuffed or cuffed ETT were used in paediatric patients (newborn to 5 years) undergoing elective surgery in a randomized order. Duration of assessment, lowest possible fresh gas flow (minimal allowed FGF: 0.5 l/min) and sevoflurane concentrations used were recorded. Consumption and costs for sevoflurane and medical gases were calculated. Results: Seventy children (35 uncuffed ETT/35 cuffed ETT), aged 1.73 (0.01,4.80) years, were enrolled. No significant differences in patient characteristics, study period and sevoflurane concentrations used were found between the two groups. Lowest possible FGF was significantly lower in the cuffed ETT group [1.0 (0.5,1.0) l/min] than in the uncuffed ETT group [2.0 (0.5,4.3) l/min], P<0.001. Sevoflurane consumption per patient was 16.1 (6.4,82.8) ml in the uncuffed ETT group and 6.2 (1.1,14.9) ml in the cuffed ETT group, P=0.003. Medical gas consumption was 129 (53,552) l in the uncuffed ETT group vs. 46 (9,149) l in the cuffed ETT group, P<0.001. The total costs for sevoflurane and medical gases were 13.4 (6.0,67.3),/patient in the uncuffed ETT group and 5.2 (1.0,12.5),/patient in the cuffed ETT group, P<0.001. Conclusions: The use of cuffed ETT in children significantly reduced the costs of sevoflurane and medical gas consumption during anaesthesia. Increased costs for cuffed compared with uncuffed ETT were completely compensated by a reduction in sevoflurane and medical gas consumption. [source] Study of a fuel cell network with water electrolysis for improving partial load efficiency of a residential cogeneration systemINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 8 2006S. Obara Abstract A fuel cell energy network which connects hydrogen and oxygen gas pipes, electric power lines and exhaust heat output lines of the fuel cell cogeneration for individual houses, respectively, is analysed. As an analysis case, the energy demand patterns of individual houses in Tokyo are used, and the analysis method for minimization of the operational cost using a genetic algorithm is described. The fuel cell network system of an analysis example assumed connecting the fuel cell cogeneration of five houses. If energy is supplied to the five houses using the fuel cell energy network proposed in this paper, 9% of city gas consumption will be reduced by the maximum from the results of analysis. Two per cent included with 9% is an effect of introducing water electrolysis operation of the fuel cells, corresponding to partial load operation of fuel cell cogeneration. Copyright © 2005 John Wiley & Sons, Ltd. [source] Entropy injection as a global feedback mechanismMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2003S. Peng Oh ABSTRACT Both pre-heating of the intergalactic medium and radiative cooling of low entropy gas have been proposed to explain the deviation from self-similarity in the cluster LX,TX relation and the observed entropy floor in these systems. However, severe overcooling of gas in groups is necessary for radiative cooling alone to explain the observations. Non-gravitational entropy injection must therefore still be important in these systems. We point out that, on scales of groups and below, gas heated to the required entropy floor cannot cool in a Hubble time, regardless of its subsequent adiabatic compression. Pre-heating therefore shuts off the gas supply to galaxies, and should be an important global feedback mechanism for galaxy formation. Constraints on global gas cooling can be placed from the joint evolution of the comoving star formation rate and neutral gas density. Pre-heating at high redshift can be ruled out; however, the data do not rule out passive gas consumption without inflow as z, 2. Because for pre-heated gas tcool > tdyn, we speculate that pre-heating could play a role in determining the Hubble sequence; at a given mass scale, high , peaks in the density field collapse early to form ellipticals, while low , peaks collapse late and quiescently accrete pre-heated gas to form spirals. The entropy produced by large-scale shock-heating of the intergalatic medium is significant only at late times, z < 1, and cannot produce these effects. [source] Indonesia fights off oil and gas crisesOIL AND ENERGY TRENDS, Issue 4 2005Article first published online: 12 APR 200 Rising domestic consumption and falling output have turned Indonesia into a net importer of oil, forcing it to consider withdrawing from OPEC. In recent years, Jakarta has depended on gas for its export revenues. Now, the gas industry is in trouble. Output from the Arun gas fields is declining and the state oil and gas company, Pertamina, was recently forced to delay LNG shipments to its three largest customers. The government is looking for new investment in an attempt to stave off an energy crisis, but foreign companies are unhappy about business conditions there. Meanwhile, oil and gas consumption is rising rapidly thanks to a system of domestic price subsidies, which the government has been unable to end. The delay to much needed reforms in the energy sector threatens not only the oil and gas industries but the economic and political stability of the country as well. [source] Industrial energy policy: a case study of demand in KuwaitOPEC ENERGY REVIEW, Issue 2 2006M. Nagy Eltony The purpose behind building the industrial energy demand model was to enable assessment of the impact of potential policy options and to forecast future energy demand under various assumptions, including the impact of the possible removal of energy subsidies in accordance with the World Trade Organization (WTO) agreement. The results of the model, based on three scenarios, underline several important issues: With nominal energy prices staying the same (the status quo) and with inflation and economic growth continuing to expand (i.e. baseline scenario), it is expected that industrial demand will grow. In this sector, energy consumption is projected to grow at an annual growth rate of about 3.5 per cent throughout the forecast period. In the moderate scenario, however, this drops to 1.9 per cent and when all energy subsidies are removed as in the case of the extreme scenario, the energy consumption is projected to grow by only 1.5 per cent annually throughout the same period. Moreover, with regards to inter-fuel substitution, the model forecast indicates that electricity and natural gas consumption will decline, while the consumption of oil products will increase in all scenarios. The results of the model also indicate that the changing price structure of energy resources should be done in a comprehensive manner. In other words, electricity prices should be adjusted upwards instantly with the adjustment of oil products' prices and natural gas otherwise, a massive inter-fuel substitution will occur within the various consuming industries. [source] Study of the Kinetics and Morphology of Gas Hydrate FormationCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 8 2006Abstract The kinetics and morphology of ethane hydrate formation were studied in a batch type reactor at a temperature of ca. 270,280,K, over a pressure range of 8.83,16.67,bar. The results of the experiments revealed that the formation kinetics were dependant on pressure, temperature, degree of supercooling, and stirring rate. Regardless of the saturation state, the primary nucleation always took place in the bulk of the water and the phase transition was always initiated at the surface of the vortex (gas-water interface). The rate of hydrate formation was observed to increase with an increase in pressure. The effect of stirring rate on nucleation and growth was emphasized in great detail. The experiments were performed at various stirring rates of 110,190,rpm. Higher rates of formation of gas hydrate were recorded at faster stirring rates. The appearance of nuclei and their subsequent growth at the interface, for different stirring rates, was explained by the proposed conceptual model of mass transfer resistances. The patterns of gas consumption rates, with changing rpm, have been visualized as due to a critical level of gas molecules in the immediate vicinity of the growing hydrate particle. Nucleation and decomposition gave a cyclic hysteresis-like phenomena. It was also observed that a change in pressure had a much greater effect on the rate of decomposition than it did on the formation rate. Morphological studies revealed that the ethane hydrate resembles thread or is cotton-like in appearance. The rate of gas consumption during nucleation, with different rpm and pressures, and the percentage decomposition at different pressures, were explained precisely for ethane hydrate. [source] | ||||||||||