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Fuel
Kinds of Fuel Terms modified by Fuel Selected AbstractsDUNG BY PREFERENCE: THE CHOICE OF FUEL AS AN EXAMPLE OF HOW ANDEAN POTTERY PRODUCTION IS EMBEDDED WITHIN WIDER TECHNICAL, SOCIAL, AND ECONOMIC PRACTICES,ARCHAEOMETRY, Issue 1 2000B. SILLAR A discussion of how Andean potters acquire and use their fuels is used to demonstrate the ,embedded'nature of ceramic technology. The most common choice of fuel in the highlands of Peru and Bolivia is animal dung (mainly cow, sheep, and llama). This technological choice is related to wider social and economic practices (particularly in relation to animal husbandry) which has further repercussions that affect other technologies (such as agriculture practices). Such a succession of interrelated activities is not unique to pottery; it is fundamental to all technologies and should be considered within archaeological analysis. [source] Combustion of a substitution fuel made of cardboard and polyethylene: influence of the mix characteristics,modelingFIRE AND MATERIALS, Issue 7 2008S. Salvador Abstract The model proposed in this paper describes the combustion of a porous medium subjected to a radiative heat flux at its surface. There is no forced convection of air through the medium; hence this situation corresponds to the one encountered at the surface of fuel elements such as pellets, bricks or ballots, inside a furnace or kiln. Ash is not removed from the surface. No assumption is made a priori in terms of the limiting phenomena. The medium is composed of cardboard and polyethylene (PE). Based on previous experimental work (Fuel 2004; 83:451,462), the material is assumed to be a macroscopically homogeneous porous medium. Local thermal equilibrium is also assumed. Most of the parameters required for the modeling were determined from specific experiments. Good predictions of the sample mass evolution and of the temperature levels inside the sample body were obtained for a large range of densities and PE content. A devolatilization front of about 20,mm first propagates inside the medium. The volatile matter flux is advected to the surface, which leads to the formation of the flame above the surface. Then a second char oxidation front propagates, starting from the surface. The front thickness is approximately 25,mm under the experimental conditions. Copyright © 2008 John Wiley & Sons, Ltd. [source] Hydrogen Production via Autothermal Reforming of Diesel FuelFUEL CELLS, Issue 3 2004J. Pasel Abstract Hydrogen, for the operation of a polymer electrolyte fuel cell, can be produced by means of autothermal reforming of liquid hydrocarbons. Experiments, especially with ATR 4, which produces a molar hydrogen stream equivalent to an electrical power in the fuel cell of 3,kW, showed that the process should be preferably run in the temperature range between 700,° and 850,°. This ensures complete hydrocarbon conversion and avoids the formation of considerable amounts of methane and organic compounds in the product water. Experiments with commercial diesel showed promising results but insufficient long-term stability. Experiments concerning the ignition of the catalytic reaction inside the reformer proved that within 60,s after the addition of water and hydrocarbons the reformer reached 95% of its maximum molar hydrogen flow. Measurements, with respect to reformer start-up, showed that it takes approximately 7,min. to heat up the monolith to a temperature of 340,° using an external heating device. Modelling is performed, aimed at the modification of the mixing chamber of ATR Type 5, which will help to amend the homogeneous blending of diesel fuel with air and water in the mixing chamber. [source] Utilization of semi-natural grassland through integrated generation of solid fuel and biogas from biomass.GRASS & FORAGE SCIENCE, Issue 4 2009Abstract A procedure (Integrated Generation of Solid Fuel and Biogas from Biomass, IFBB) was developed which uses a screw press to separate the readily digestible constituents of mature grassland biomass into a press fluid for conversion into biogas and a fibrous press cake for processing into a solid fuel. Effects of mechanical dehydration and prior hydrothermal conditioning at different temperatures (5, 60 and 80°C) on concentrations of organic compounds in the press fluid and on methane production in batch experiments were evaluated for five semi-natural grasslands typical of mountain areas of Germany. Results show that the crude protein concentration of the press fluids was higher and crude fibre concentration was lower than that of the parent material (herbage conserved as silage). Digestion tests in batch fermenters showed that the methane yield of the press fluids was double [397,426 normal litre (NL) kg,1 volatile solids (VS) after 13 d] that of the whole-crop grassland silage (218 NL kg,1 VS after 27 d) but no consistent effect of higher temperature during conditioning was observed. Within 13 d of fermentation the decomposition of the organic matter (OM) that occurred in the press fluids was 0·90, whereas after 27 d of fermentation more than 0·40 of the OM remained undigested in the whole-crop silage, pointing at a marked reduction in retention time for anaerobic digestion of press fluids in continuous systems. Press fluids produced 0·90 of the maximum methane yield after 4 to 7 d compared with 19 days for the whole-crop silage. [source] Drag reduction by flow separation control on a car after bodyINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 11 2009Mathieu Rouméas Abstract New development constraints prompted by new pollutant emissions and fuel consumption standards (Corporate Average Economy Fuel) require that automobile manufacturers develop new flow control devices capable of reducing the aerodynamic drag of motor vehicles. The solutions envisaged must have a negligible impact on the vehicle geometry. In this context, flow control by continuous suction is seen as a promising alternative. The control configurations identified during a previous 2D numerical analysis are adapted for this purpose and are tested on a 3D geometry. A local suction system located on the upper part of the rear window is capable of eliminating the rear window separation on simplified fastback car geometry. Aerodynamic drag reductions close to 17% have been obtained. Copyright © 2008 John Wiley & Sons, Ltd. [source] The effect of fire season, fire frequency, rainfall and management on fire intensity in savanna vegetation in South AfricaJOURNAL OF APPLIED ECOLOGY, Issue 4 2006NAVASHNI GOVENDER Summary 1Fire is important for the maintenance and conservation of African savanna ecosystems. Despite the importance of fire intensity as a key element of the fire regime, it is seldom measured or included in fire records. 2We estimated fire intensity in the Kruger National Park, South Africa, by documenting fuel loads, fuel moisture contents, rates of fire spread and the heat yields of fuel in 956 experimental plot burns over 21 years. 3Individual fires were conducted in five different months (February, April, August, October and December) and at five different return intervals (1, 2, 3, 4 and 6 years). Estimated fire intensities ranged from 28 to 17 905 kW m,1. Fire season had a significant effect on fire intensity. Mean fire intensities were lowest in summer fires (1225 kW m,1), increased in autumn fires (1724 kW m,1) and highest in winter fires (2314 kW m,1); they were associated with a threefold difference between the mean moisture content of grass fuels in winter (28%) and summer (88%). 4Mean fuel loads increased with post-fire age, from 2964 kg ha,1 on annually burnt plots to 3972 kg ha,1 on biennial, triennial and quadrennial burnt plots (which did not differ significantly), but decreased to 2881 kg ha,1 on sexennial burnt plots. Fuel loads also increased with increasing rainfall over the previous 2 years. 5Mean fire intensities showed no significant differences between annual burns and burns in the biennial, triennial and quadrennial categories, despite lower fuel loads in annual burns, suggesting that seasonal fuel moisture effects overrode those of fuel load. Mean fire intensity in sexennial burns was less than half that of other burns (638 vs. 1969 kW m,1). 6We used relationships between season of fire, fuel loads and fire intensity in conjunction with the park's fire records to reconstruct broad fire intensity regimes. Changes in management from regular prescribed burning to ,natural' fires over the past four decades have resulted in a decrease in moderate-intensity fires and an increase in high-intensity fires. 7The highest fire intensities measured in our study (11 000 , > 17 500 kW m,1) were significantly higher than those previously reported for African savannas, but were similar to those in South American cerrado vegetation. The mean fire intensity for late dry season (winter) fires in our study was less than half that reported for late dry season fires in savannas in northern Australia. 8Synthesis and applications. Fire intensity has important effects on savanna vegetation, especially on the dynamics of the tree layer. Fire intensity varies with season (because of differences in fuel moisture) as well as with fuel load. Managers of African savannas can manipulate fire intensity by choosing the season of fire, and further by burning in years with higher or lower fuel loads. The basic relationships described here can also be used to enhance fire records, with a view to building a long-term data set for the ongoing assessment of the effectiveness of fire management. [source] TEM/STEM Observation of ZrC Coating Layer for Advanced High-Temperature Gas-Cooled Reactor Fuel, Part IIJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2009Jun Aihara The Japan Atomic Energy Agency (JAEA) has started to study and develop zirconium carbide (ZrC)-coated fuel particles for advanced high-temperature gas-cooled reactors. The ZrC coating layer has been fabricated at JAEA by chemical vapor deposition using a pyrolytic reaction of zirconium bromide. The microstructures of the ZrC layers, whose nominal deposition temperatures could be measured and controlled during the deposition process, were characterized by means of TEM and STEM. In the present study, three batches were prepared and compared with each other as well as the previous batches. The crystallographic orientation of ZrC with regard to the growth direction in the ZrC layers deposited at a constant temperature of 1630 K was different from that deposited at varying temperatures in the 1493,1823 K range. A thin layer of turbostratic carbon was observed at the boundary between pyrolytic carbon and ZrC in particles deposited at the highest temperature among those used in this study (the nominal temperature was 1769 K); no such structure was found in a batch deposited at a lower temperature (the nominal temperature was 1632 K). Therefore, precise control of temperature is shown to be critical to the formation of good ZrC coatings. [source] The Sociological Department at the Colorado Fuel and Iron Company, 1901 to 1907: Scientific paternalism and industrial controlJOURNAL OF THE HISTORY OF THE BEHAVIORAL SCIENCES, Issue 3 2005Frank J. Weed The Colorado Fuel and Iron Company's Sociological Department represented an industrial welfare plan based on an early understanding of applied sociology. The Department was created as a response to the demands of integrating coal and coke production with steel manufacturing, and the necessity of combating strikes among the immigrant workers. The "settlement house model" used by the Sociological Department was intended to foster labor stability by transforming the lifestyles and habits of the immigrant workers and their families. It is concluded that the industrial welfare programs that were intended to inspire loyalty to the company merely added to the workers' grievances with the company. © 2005 Wiley Periodicals, Inc. [source] Erosion-corrosion of laser and thermally deposited coatings exposed in fluidised bed combustion plantsMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 4 2006A. Hjörnhede Abstract Coated low alloyed steel tubes were exposed in two combustion power plants of the type Circulating Fluidised Bed (CFB) and Pressurised Fluidised Bed Combustion (PFBC). The power plants were fired with wood chips and coal with a small addition of olive seeds, respectively. In addition to laser coating two thermal spray techniques were used; arc-spray (air as carrier gas) and High Velocity Oxy Fuel (HVOF). The sample locations in the PFBC plant were at the highest and lowest loops of a platen immersed in the fluidising bed. The material temperatures in each loop were 450 °C and 400 °C, respectively. The exposure lasted over two firing seasons for a total time of 8089 h. In the CFB plant a probe was located at the cyclone entrance where the material temperature was 630 °C for an exposure time of about 2100 h before being reduced to 480 °C for a further 920 h. The material wastage was determined from metallographic studies on cross-sections of rings cut from the exposed tubes. The nature and chemical composition of the corrosion products and deposits formed were determined by SEM/EDX, Auger spectroscopy, XPS and XRD. Cobalt based coatings show the best performance in both the PFBC plant and the CFB plant, while nickel based coatings are resistant to a corrosive atmosphere but very sensitive to erosion. The degree of corrosion is much larger in the CFB plant as is clearly seen from the chromium carbide containing coating, which totally degraded in this environment. Contrary the performance of the same coating was excellent in the fluidised bed due to its high erosion resistance. The material wastage of a coating with a specific composition is independent of the deposition method. No significant differences in spallation behaviour occurred among coatings deposited with the different techniques. [source] Efficient Production of the Liquid Fuel 2,5-Dimethylfuran from Fructose Using Formic Acid as a Reagent,ANGEWANDTE CHEMIE, Issue 37 2010Todsapon Thananatthanachon Dr. Drei in einem: Für die Erzeugung flüssiger Kraftstoffe aus Biomasse werden neue, vielseitige Reagentien benötigt. Ein Beispiel hierfür ist Ameisensäure, die bei der Umsetzung von Fructose in die Titelverbindung 1 drei Funktionen erfüllt: Sie vermittelt die Isomerisierung-Dehydratisierung, dient als H2 -Quelle für die Hydrierung und unterstützt die Desoxygenierung von Alkoholfunktionalitäten. [source] Dissipative Self-Assembly of a Molecular Gelator by Using a Chemical Fuel,ANGEWANDTE CHEMIE, Issue 28 2010Job Boekhoven Die Natur macht's vor: Die dissipative Selbstorganisation eines synthetischen Gelbildners (blau, siehe Bild) wird durch ein Alkylierungsreagens angetrieben und führt über einen aktivierten Baustein (rot) als Zwischenstufe zur Bildung eines Fasernetzwerks. Nach vollständiger Ausschöpfung der Energieressourcen kehrt das System in das thermodynamische Gleichgewicht zurück. [source] Efficient Regeneration of Partially Spent Ammonia Borane Fuel,ANGEWANDTE CHEMIE, Issue 37 2009Benjamin Der Kreis schließt sich: Ammoniakboran ist ein potenzieller H2 -freisetzender Brennstoff. Aus Polyborazylen, einer Form des verbrauchten Brennstoffs, lässt sich durch schrittweise Zugabe von abbauenden und reduzierenden Reagentien in einem Eintopfprozess H3B-NH3 regenerieren. Ein besonderes Merkmal dieses Prozesses ist die Bildung von NH3, das von einigen der Abbauprodukte fixiert wird. [source] Grassfires: Fuel, Weather and Fire Behaviour, 2nd editionAUSTRAL ECOLOGY, Issue 8 2009F. PATRICK GRAZ No abstract is available for this article. [source] An Investigation into the Transient Behavior of a Microreactor System for Reforming of Diesel Fuel in the kW RangeCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 11 2009M. O'Connell Abstract A diesel reformer based on microreaction technology was developed for application in an auxiliary power unit (APU) system. The transient characteristics of this reactor for reforming of diesel fuel are reported. Diesel steam reforming was performed at various S/C ratios with load changes ranging from 30 % LL to 80 % LL, i.e., a 1.5 kW to a 4 kW electrical equivalent. The reactor itself was based on an integrated reformer/burner heat exchange reactor concept. The reforming was performed at temperatures above 750,°C and at various S/C ratios, down to a minimum of 3.17. Variation of experimental parameters, such as O/C and S/C ratios, are critical for optimum and efficient operation of the reformer. [source] Kinetic and Statistical Studies of Adsorptive Desulfurization of Diesel Fuel on Commercial Activated CarbonsCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 3 2008M. Muzic Abstract Diesel fuel desulfurization by different commercial activated carbons was studied in a batch adsorber. Experiments, carried out to determine the sulfur adsorption dependency on time, were used to perform kinetic characterization and to screen the best performing activated carbon. The equilibrium characterization of the adsorption process was also performed. The statistical study of the process was undertaken by way of a two-level one-half fractional factorial experimental design with five process parameters. Individual parameters and their interaction effects on sulfur adsorption were determined and a statistical model of the process was developed. Chemviron Carbon SOLCARBTM C3 was found to be the most efficient adsorbent. The kinetic pseudo-second order model and Freundlich isotherm are shown to exhibit the best fits of experimental data. The lowest achieved sulfur concentration in treated diesel fuel was 9.1,mg kg,1. [source] Investigation of Soot Formation During Partial Oxidation of Diesel FuelCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 6 2007K. Roth Abstract Soot formation during partial oxidation is a major issue for hydrogen production from liquid hydrocarbon fuels. Measurements were made to investigate the sooting behavior of diesel fuel under variation of the main operating parameters temperature (T = 800 to 1300,°C), pressure (p = 1 to 3,bar), equivalence ratio (, =1 to 3), and steam ratio (H2O/C = 0.2 to 0.6) at constant residence time. The experimental setup was a perfectly stirred/plug flow reactor (PSR/PFR system) providing conditions close to reality. The study proves that soot growth rate strongly depends on temperature, pressure, and equivalence ratio while adding water has a minor effect on soot growth. Experimental results were compared with a kinetic model developed by the Institut Français du Pétrole (IFP), predicting soot formation during the partial oxidation of liquid hydrocarbon fuels. The calculated amount of soot shows good agreement with the measured data. [source] Critical Role of Water Content in the Formation and Reactivity of Uranium, Neptunium, and Plutonium Iodates under Hydrothermal Conditions: Implications for the Oxidative Dissolution of Spent Nuclear Fuel.CHEMINFORM, Issue 30 2007Travis H. Bray Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Application of New Organic Fuels in the Direct MgAl2O4 Combustion SynthesisEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 6 2008Robert Iano Abstract The paper presents a new version of MgAl2O4 solution-combustion synthesis, based on the individual reactivity of Mg(NO3)2 and Al(NO3)3 with respect to various fuels. Beside the traditionally used fuels (urea, glycine, ,-alanine), new organic reducing agents [monoethanolamine, triethanolamine, tris(hydroxymethyl)aminomethane and triethylenetetramine] have also been used. The study of the individual reactivities of Mg(NO3)2 and Al(NO3)3 with respect to each of the previously mentioned fuels suggested that there is a predilection of the two metal nitrates for certain fuels: urea is the optimum fuel for Al(NO3)3, whereas monoethanolamine represents the most suitable fuel for Mg(NO3)2. It has been shown by X-ray diffraction and thermal analysis that the use of a single fuel in the MgAl2O4 low-temperature combustion synthesis leads to the formation of an amorphous powder. In this case, the formation of pure crystalline MgAl2O4 requires a subsequent thermal treatment at 900 °C with 1 h soaking time. On the other hand, the use of fuel mixtures containing urea and monoethanolamine or urea and ,-alanine proved to be the rational solution for the direct formation of MgAl2O4. It has been shown that, by using the above-mentioned fuel mixtures, one can obtain pure nanocrystalline MgAl2O4 straight from the combustion reaction, no additional calcination being necessary. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] The Future of Gaseous Fuels in Hong KongOPEC ENERGY REVIEW, Issue 1 2001Larry Chuen-ho Chow There are three types of gaseous fuel in Hong Kong. Natural gas, exclusively used for power generation and imported under a 20-year contract, accounted for 16 per cent of total primary energy requirements in 1998. Towngas, manufactured from naphtha, and liquefied petroleum gas are the two other kinds, accounting for about 9.5 per cent of the final energy requirement in recent years. The first part of this paper analyses the competition between these two gaseous fuels since 1984, elucidating in detail how towngas came to dominate the gaseous fuel market. The government of the Hong Kong Special Administrative Region would like to boost the use of natural gas in Hong Kong, on account of its environmental benefits and cost competitiveness. It is considering the possibility of using natural gas to replace the other two gaseous fuels and adopting the common carrier system, in order to spur competition in the gaseous fuel market. The second part of the study evaluates the feasibility of converting to natural gas and opening up the pipeline system, putting forth a rough schedule for the whole process. [source] Valeric Biofuels: A Platform of Cellulosic Transportation Fuels,ANGEWANDTE CHEMIE, Issue 26 2010Jean-Paul Lange Dr. Kraftstoff für die Zukunft: Valeriansäureester werden durch Säurehydrolyse von Lignocellulose zu Lävulinsäure und anschließende Hydrierung zu Valeriansäure mit nachfolgender Veresterung synthetisiert (siehe Schema). Valerianbiokraftstoffe sind vollständig kompatibel für Mischungen mit Benzin und Diesel und bestanden einen Straßentest über 250,000,km. [source] Development of a Characterization Method for the Combustion Behavior of Solid Recovered FuelsCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 7 2004O. Kock Apart from coal, fuels like solid biogenic or recovered fuels will gain increasing importance in power generation plants because of their potential to lower CO2 emissions. In order to produce a constant fuel quality and to guarantee a safe power plant operation, it is rather important to know the combustion behavior of the different fuel types. A characterization method is proposed by which the combustion behavior of solid fuels can be analyzed with low-cost equipment and reliable results. [source] Catalytic Production of Fuels and Chemicals from Biomass-derived Oxygenated HydrocarbonsCHEMIE-INGENIEUR-TECHNIK (CIT), Issue 9 2008J. A. Dumesic No abstract is available for this article. [source] Influence of oil-atomized air on flow and combustion characteristics in a 300 MWe down-fired boilerASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2010Zhengqi Li Abstract A method of admitting oil-atomized air into a furnace to adjust coal combustion in a down-fired boiler is described. Experiments with a small-scale furnace simulating a down-fired, pulverized-coal, 300-MWe utility boiler were carried out at a single-phase test facility to investigate the influence of oil-atomized air on the aerodynamic field in the furnace. With the acceleration of oil by secondary air, the primary air/fuel can reach a more distant position with respect to the burner nozzle and the volume of the recirculation zone shrinks. Industrial experiments were also performed in a 300-MWe full-scale boiler. The gas temperature distribution along the primary air/fuel flow in the furnace and the gas components in the near-wall region were measured with the dampers of the oil-atomized air box open and closed. When open, the oil-atomized air does not impede the ignition of the primary air/fuel and can carry the primary air/fuel to a position much deeper in the furnace, resulting in a lowered carbon content in the fly ash. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] The regulation of muscle glycogen: the granule and its proteinsACTA PHYSIOLOGICA, Issue 4 2010T. E. Graham Abstract Despite decades of studying muscle glycogen in many metabolic situations, surprisingly little is known regarding its regulation. Glycogen is a dynamic and vital metabolic fuel that has very limited energetic capacity. Thus its regulation is highly complex and multifaceted. The stores in muscle are not homogeneous and there appear to be various metabolic pools. Each granule is capable of independent regulation and fundamental aspects of the regulation appear to be associated with a complex set of proteins (some are enzymes and others serve scaffolding roles) that associate both with the granule and with each other in a dynamic fashion. The regulation includes altered phosphorylation status and often translocation as well. The understanding of the roles and the regulation of glycogenin, protein phosphatase 1, glycogen targeting proteins, laforin and malin are in their infancy. These various processes appear to be the mechanisms that give the glycogen granule precise, yet dynamic regulation. [source] Fat as a fuel: emerging understanding of the adipose tissue,skeletal muscle axisACTA PHYSIOLOGICA, Issue 4 2010K. N. Frayn Abstract The early pioneers in the field of metabolism during exercise such as Lindhard and Krogh understood the importance of fat as a fuel for muscle contraction. But they could not have understood the details of the pathways involved, as neither the metabolic role of adipose tissue nor the transport role of non-esterified fatty acids (NEFA) in the plasma was clearly understood at the time. We now recognize that the onset of muscular contraction coincides with an increase in the delivery of NEFA from adipose tissue, probably coordinated by the sympatho-adrenal system. During light exercise, adipose tissue-derived NEFA make up the majority of the oxidative fuel used by muscle. As exercise is prolonged, the importance of NEFA increases. The onset of exercise is marked by an increased proportion of NEFAs entering ,-oxidation rather than re-esterification and recycling. At moderate intensities of exercise, other sources of fat, potentially plasma- and intramyocellular-triacylglycerol, supplement the supply of plasma NEFA. The delivery of NEFA is augmented by increased adipose tissue blood flow and by other stimuli such as atrial natriuretic peptide. Only during high-intensity exercise is there a failure of adipose tissue to deliver sufficient fatty acids for muscle (which is coupled with an inability of muscle to use them, even when fatty acids are supplied artificially). This limitation of adipose tissue NEFA delivery may reflect some feedback inhibition of lipolysis, perhaps via lactate, or possibly ,-adrenergic inhibition of lipolysis at very high catecholamine concentrations. [source] Regional industrial recycling network in energy supply,the case of Joensuu city, FinlandCORPORATE SOCIAL RESPONSIBILITY AND ENVIRONMENTAL MANAGEMENT, Issue 3 2002Jouni Korhonen Industrial recycling networks offer an example of the practical application of some of the industrial ecology (IE) principles. In the industrial ecosystem and eco-industrial park approaches the material cycles and energy cascades in a natural ecosystem serve as the metaphoric vision for a local/regional industrial system in which waste material and waste (residual) energy are utilized through cooperation between the actors in the system. In this paper, a local/regional recycling network scenario is presented with the energy supply system of the city of Joensuu in Finland. The conditions of success include the co-production of heat and electricity (heat and power, CHP), waste energy utilization for industrial steam and renewable flow use as fuel. Some difficulties in the industrial ecosystem-type development of the system are discussed. Methodological suggestions for industrial ecosystem and eco-industrial park case studies are considered and the experience from this Finnish case is discussed in terms of wider application of IE in local/regional economic energy systems. For future research on the theme, it is suggested that regional industrial ecology may benefit from regional economics theory and, vice versa, regional economics theory may find a new area of application in regional industrial ecology. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment. [source] The role of intramuscular lipid in insulin resistanceACTA PHYSIOLOGICA, Issue 4 2003B. D. Hegarty Abstract There is interest in how altered lipid metabolism could contribute to muscle insulin resistance. Many animal and human states of insulin resistance have increased muscle triglyceride content, and there are now plausible mechanistic links between muscle lipid accumulation and insulin resistance, which go beyond the classic glucose,fatty acid cycle. We postulate that muscle cytosolic accumulation of the metabolically active long-chain fatty acyl CoAs (LCACoA) is involved, leading to insulin resistance and impaired insulin signalling or impaired enzyme activity (e.g. glycogen synthase or hexokinase) either directly or via chronic translocation/activation of mediators such as a protein kinase C (particularly PKC , and ,). Ceramides and diacylglycerols (DAGs) have also been implicated in forms of lipid-induced muscle insulin resistance. Dietary lipid-induced muscle insulin resistance in rodents is relatively easily reversed by manipulations that lessen cytosolic lipid accumulation (e.g. diet change, exercise or fasting). PPAR agonists (both , and ,) also lower muscle LCACoA and enhance insulin sensitivity. Activation of AMP-activated protein kinase (AMPK) by AICAR leads to muscle enhancement (especially glycolytic muscle) of insulin sensitivity, but involvement of altered lipid metabolism is less clear cut. In rodents there are similarities in the pattern of muscle lipid accumulation/PKC translocation/altered insulin signalling/insulin resistance inducible by 3,5-h acute free fatty acid elevation, 1,4 days intravenous glucose infusion or several weeks of high-fat feeding. Recent studies extend findings and show relevance to humans. Muscle cytosolic lipids may accumulate either by increased fatty acid flux into muscle, or by reduced fatty acid oxidation. In some circumstances muscle insulin resistance may be an adaptation to optimize use of fatty acids when they are the predominant available energy fuel. The interactions described here are fundamental to optimizing therapy of insulin resistance based on alterations in muscle lipid metabolism. [source] Fate of fatty acids at rest and during exercise: regulatory mechanismsACTA PHYSIOLOGICA, Issue 4 2003M. D. Jensen Abstract Fatty acids are a major fuel source for humans both at rest and during exercise. Plasma free fatty acids (FFA), although present only in micromolar concentrations, are the major circulating lipid fuel. FFA availability can increase two- to four-fold with moderate intensity exercise. Other potential sources of fatty acids include circulating very low-density lipoprotein (VLDL) triglycerides (TGs) (,1/5 the fuel availability of FFA) and intramyocellular TGs (,2 mmol kg,1 muscle). At rest ,40% of systemic FFA uptake occurs in the splanchnic bed and uptake in legs is ,15,20%. During leg exercise the uptake of FFA in leg tissue increases to 30,60% of systemic uptake and splanchnic uptake decreases to 15%. The fate of VLDL TG fatty acids has not been adequately studied. Intramyocellular TG hydrolysis increases during exercise, but the factors that regulate this response are not clear. The fact that contraction of isolated muscles can stimulate the hydrolysis and oxidation of intramyocellular TGs (in the absence of hormonal or neural input) suggests an intracellular regulation of this process. Additional regulation from changes in catecholamines and insulin may also occur. During moderate intensity exercise circulating FFA and intramyocellular TG provide roughly equal portions of fatty acids for oxidation. In addition to endurance training, dietary factors have been shown to modulate the fatty acid oxidation response to exercise. Much remains to be learned about fatty acid trafficking during exercise. What role do VLDL TG play? How is the oxidation of intramyocellular TGs regulated? Techniques to address these questions in humans are only now becoming available. [source] An Analysis of Independent Power Projects in Africa: Understanding Development and Investment OutcomesDEVELOPMENT POLICY REVIEW, Issue 3 2008Katharine Nawaal Gratwick This study analyses the outcomes of African independent power projects (IPPs). Nearly 40 such projects have taken root to date, concentrated mainly in 8 countries. More balanced outcomes are perceived in North Africa than across sub-Saharan Africa (SSA), for reasons linked to more attractive investment environments, more robust policy frameworks, fewer planning mishaps, abundant low-cost fuel and secure fuel contracts as well as credit enhancements such as sovereign guarantees. With few exceptions, these elements were absent in SSA, where the role of development finance institutions and the strategic management of projects seem more important. [source] Diabetes mellitus and alcoholDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 4 2004Albert van de Wiel Abstract Alcohol influences glucose metabolism in several ways in diabetic patients as well as in non-diabetic patients. Since alcohol inhibits both gluconeogenesis and glycogenolysis, its acute intake without food may provoke hypoglycaemia, especially in cases of depleted glycogen stores and in combination with sulphonylurea. Consumed with a meal including carbohydrates, it is the preferred fuel, which may initially lead to somewhat higher blood glucose levels and hence an insulin response in type 2 diabetic patients. Depending on the nature of the carbohydrates in the meal, this may be followed by reactive hypoglycaemia. Moderate consumption of alcohol is associated with a reduced risk of atherosclerotic disorders. Diabetic patients benefit from this favourable effect as much as non-diabetic patients. Apart from effects on lipid metabolism, haemostatic balance and blood pressure, alcohol improves insulin sensitivity. This improvement of insulin sensitivity may also be responsible for the lower incidence of type 2 diabetes mellitus reported to be associated with light-to-moderate drinking. In case of moderate and sensible use, risks of disturbances in glycaemic control, weight and blood pressure are limited. Excessive intake of alcohol, however, may not only cause loss of metabolic control, but also annihilate the favourable effects on the cardiovascular system. Copyright © 2004 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||||||||||||||||||||||||||||||||