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Energy Consumption (energy + consumption)
Kinds of Energy Consumption Selected AbstractsResidential Energy Consumption: 1987 to 1997FAMILY & CONSUMER SCIENCES RESEARCH JOURNAL, Issue 3 2002Becky L. Yust The purpose of this study was to examine energy-conserving practices and consumption from 1987 to 1997 using a human ecosystem framework. Research on energy consumption and practices at the household level has been minimal in recent years. Factors that influence household energy consumption were examined, including climate, demographic characteristics of the households, housing characteristics including weatherization features and appliances, and occupant behaviors. This study was a secondary analysis of data compiled by the Energy Information Administration from the 1987, 1990, 1993, and 1997 Residential Energy Consumption Surveys and included only owner-occupied, single-family detached residences. Based on multiple regression analyses, more than 30% of the household energy consumption was accounted for by the variables representing the environments of the human ecosystem. [source] Optimization of Train Speed Profile for Minimum Energy ConsumptionIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 3 2010Masafumi Miyatake Member Abstract The optimal operation of railway systems minimizing total energy consumption is discussed in this paper. Firstly, some measures of finding energy-saving train speed profiles are outlined. After the characteristics that should be considered in optimizing train operation are clarified, complete optimization based on optimal control theory is reviewed. Their basic formulations are summarized taking into account most of the difficult characteristics peculiar to railway systems. Three methods of solving the formulation, dynamic programming (DP), gradient method, and sequential quadratic programming (SQP), are introduced. The last two methods can also control the state of charge (SOC) of the energy storage devices. By showing some numerical results of simulations, the significance of solving not only optimal speed profiles but also optimal SOC profiles of energy storage are emphasized, because the numerical results are beyond the conventional qualitative studies. Future scope for applying the methods to real-time optimal control is also mentioned. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Energy Consumption, Density, and Rehydration Rate of Vacuum Microwave- and Hot-Air Convection- Dehydrated TomatoesJOURNAL OF FOOD SCIENCE, Issue 6 2002T.D. Durance ABSTRACT: Vacuum to lower boiling temperature and microwaves for energy transfer can provide very rapid dehydration at low temperatures. Tomato sections were dehydrated in a batch convection air dryer (AD), a 16 kW vacuum microwave (VM) dryer, or by 1 of 3 combination processes. Drying rate of the 100% VM process was 18 times that of the 100% AD process. Only a slight falling rate effect was noted in VM drying AD and VM in sequence allowed the operator to choose any process time between 0.8 and 14.75 h. In this instance the least energy consumption occurred in the 100% VM process. Lowest energy cost was found for the 70% AD / 30% VM process. These results are expected to be strongly dependent upon the scale and design of dryers. Tomatoes finish-dried by VM exhibited a puffed structure associated with faster rehydration. [source] Evaluating Energy Consumption and Efficiency of a Twin-Screw ExtruderJOURNAL OF FOOD SCIENCE, Issue 5 2002M. Liang ABSTRACT: Using the results from twin-screw extrusion of corn meal, both energy consumption and extruder efficiency were found to be significantly correlated with screw speed and specific feeding load (SFL). An increase in the SFL decreased the total specific mechanical energy, but increased the extruder efficiency. SFL influenced the extruder efficiency more than the screw speed. Increasing the screw speed from 300 to 450 rpm at a constant SFL level increased the extruder efficiency by 6 to 11%, whereas an increase of SFL from 0.0026 to 0.0038 kg rev 1 raised the extruder efficiency by 30%. Of the mechanical energy consumed per unit mass of extrudate, over 98% were used for shearing or viscous dissipation and less than 1.5% were for pumping during twin-screw extrusion of corn meal. [source] When fish meet fish as determined by physiological sensorsECOLOGY OF FRESHWATER FISH, Issue 4 2009O. Slavík Abstract,,, Electromyogram (EMG) biotelemetry allows a description of the spatial distribution of fish together with a simultaneous measurement of individual energy consumption. Using this technique, we observed behaviour of the largest European freshwater predator, Silurus glanis, in the Elbe River, Central Europe. In total, 52 diurnal cycles and 1248 individual fish positions were recorded with 12,480 EMG records during the period from March to May 2006; 1013 fish positions with 10,130 EMG records were further used for statistical analyses. Energy consumption increased with decreasing mutual distance between specimens, an effect that occurred predominantly when both of them were simultaneously in overlapping preferred areas [core areas (CAs)] appointed within their home ranges (HRs). Furthermore, with increasing energy consumption individual's movement range in longitudinal and lateral profiles decreased; i.e., the fish were positioned within a small area. When the CAs of tested individuals did not overlap, no relationship between EMG signals and mutual distance of conspecifics was found. Our results indicate that movement activity and also social behaviour can be determined with physiological sensors. [source] Enhanced Treatment of Trace Pollutants by a Novel Electrolytic Cell,ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 6 2006Y. Sakakibara Abstract Continuous experiments were conducted to evaluate the electrolytic performance of a novel 3-dimensional electrolytic cell consisting of granular Pt/Ti electrodes. The electric current efficiency to decompose indigotrisulfonate was approx. 96,%, while energy consumption was one to two orders of magnitude smaller than that for O3 treatment. Furthermore, the cell was successfully applied to treat trace endocrine disrupting chemicals (EDCs) and chlorinated compounds. Energy consumption was in the range of 2 to 10 Wh/m3. From these results, it was concluded that the present electrolytic cell would be a feasible alternative to conventional oxidation processes in water treatment. [source] Use of various processes for pilot plant treatment of wastewater from a wood-processing factoryJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2001Nikolaos S Athanasopoulos Abstract The wastewater from a wood-processing factory is characterized by a high COD, chlorides and nitrogen content. Various treatment processes were applied to treat this wastewater in pilot-scale units. By applying one-stage denitrification,activated sludge biological treatment it was not possible to remove nitrogen. Nitrification was inhibited by wastewater compounds. By applying a second stage of a nitrification biofilter it was possible to have a high degree of nitrification. The denitrification was complete. With biological methods the reduction of COD, and -N and -N concentrations to acceptable values was not achievable. Physical,Chemical methods as H2O2/UV, electrolysis and ozonation were used as post-treatment of effluents from the biological system. Radical degradation, initiated by the powerful hydroxyl radicals which are generated from H2O2 by UV activation, is used for wastewater post-treatment. The combination of H2O2/UV was not suitable for post-treatment of this wastewater. With electrolysis, -N and COD removal can be complete. The total amount of ammonia and organic nitrogen converted to nitrate nitrogen for current density of 1.15,Adm,2 and energy consumption of 71.6,kWhm,3 was 0.35,gdm,3. Further biological denitrification is required for -N removal to permitted values. Energy consumption for the elimination of 1,kg COD was 40.4,kWh and 35.8,kWh for current densities of 0.7,Adm,2 and 1.15,Adm,2 respectively. The energy required to reach the limit value of COD equal to 150,mgdm,3 for current density of 1.15,Adm,2 was 71.6,kWhm,3. With ozonation, the COD removal can be complete. Further biological nitrification,denitrification is required to remove -N and -N to permitted values. At pH 7.0, in order to reach the limit value of COD equal to 150,mgdm,3, specific ozone dose was 6.0,g per g of COD removed and the total amount of ammonia and organic nitrogen converted to nitrate nitrogen was 0.25,gdm,3. The total equivalent energy required is estimated to be 75.0,kWhm,3. © 2001 Society of Chemical Industry [source] Energy consumption and economic growth: causality relationship for NigeriaOPEC ENERGY REVIEW, Issue 1 2010Suleiman Sa'ad In this paper, cointegration and causality between energy consumption and gross domestic product (GDP) in Nigeria over the period 1971,2006 were analysed. The study used vector error correction models to test the relationships. The results of these tests showed the existence of cointegration as well as unidirectional causality-running from GDP to energy in Nigeria. The conclusion from these results was that decline in GDP or economic recession may have an adverse effects on energy consumption in Nigeria. However, energy conservation policies could be effectively implemented without any negative consequence on the growth of GDP in Nigeria. [source] Energy consumption in the Islamic Republic of IranOPEC ENERGY REVIEW, Issue 3 2000A.M. Samsam Bakhtiari During the 20th century, energy consumption in the Islamic Republic of Iran was continually on the increase, from a per capita level of 200 kilogrammes of oil equivalent (koe) for traditional energies at the onset to more than 1,700 koe for commercial energies at the century's close. The main stimulants fuelling Iran's energy consumption were: (i) revenue from oil exports (wealth-creating); (ii) a growing population; (iii) the countrywide rural-urban shift; and (iv) relatively low domestic retail prices charged for energy vectors. For a country well endowed with hydrocarbon resources, it is not surprising that the internal consumption of refined products and natural gas grew to fill 99 per cent of its primary energy needs. During the 1990s, domestic consumption of natural gas exploded. Gas even came to rival refined products, securing up to 45 per cent of total primary energy. Future natural gas expansion will be based upon the country's ample reserves, and gas will undoubtedly become Iran's dominant source of internal energy in the 21st century,thereby liberating liquid fuels for export. Iran's dwindling crude oil production will also put pressure on the internal use of refined products, as consumption and exports come to vie for the same barrel. Exports being vital to the national economy, consumption will have to be reined in. [source] Electrochemical bleaching of kraft bagasse pulp using a new cell designTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2010El-Sayed Z. El-Ashtoukhy Abstract In situ single-stage electrochemical bleaching of kraft bagasse pulp was carried out in a cylindrical agitated vessel fitted with four graphite rod anodes and a cylindrical stainless steel screen cathode, using NaCl as an electrolyte. The effect of current density, pH, NaCl concentration, impeller rotational speed, temperature, and pulp consistency on the rate of bleaching was studied. It was found that the rate of bleaching increased with increasing current density, NaCl concentration, and temperature and decreased with increasing pH and pulp consistency. The effect of temperature was found to fit Arrhenius equation with an activation energy of 0.515,kcal/mol, which denotes a diffusion-controlled mechanism. Energy consumption (EC) calculation showed that EC ranged from 0.225 to 3.11,kWh/kg dry pulp depending on the current density. The strength of bleached pulp was little affected by bleaching lying within an acceptable range. Le blanchiment électrochimique à une étape in situ de pâte de bagasse kraft a été effectué dans un réservoir cylindrique agité doté d'une anode sous forme de tige au graphite (4) et de cathode sous forme de treillis cylindrique en acier inoxydable, utilisant le NaCl comme électrolyte. L'effet de la densité du courant, du pH, de la concentration de NaCl, de la vélocité rotationnelle de la roue et de la température de la consistance de la pâte sur le taux de blanchiment a été étudié. L'effet de la température s'est avéré s'inscrire dans l'équation d'Arrhenius avec une énergie d'activation de 0,515 kcal/mol, ce qui dénote un mécanisme de diffusion contrôlé. Le calcul de consommation d'énergie montre que la consommation d'énergie se situe de 0,225 à 3,11,kWh/kg de pâte sèche, selon la densité du courant. La résistance de la pâte blanchie est peu touchée par le blanchiment et se situe en deçà de la plage acceptable. [source] Application of Visual Analytics for Thermal State Management in Large Data CentresCOMPUTER GRAPHICS FORUM, Issue 6 2010M. C. Hao I.3.3 [Computer Graphics]: Picture/Image Generation,Display Algorithms; H.5.0 [Information Systems]: Information Interfaces and Presentation,General Abstract Today's large data centres are the computational hubs of the next generation of IT services. With the advent of dynamic smart cooling and rack level sensing, the need for visual data exploration is growing. If administrators know the rack level thermal state changes and catch problems in real time, energy consumption can be greatly reduced. In this paper, we apply a cell-based spatio-temporal overall view with high-resolution time series to simultaneously analyze complex thermal state changes over time across hundreds of racks. We employ cell-based visualization techniques for trouble shooting and abnormal state detection. These techniques are based on the detection of sensor temperature relations and events to help identify the root causes of problems. In order to optimize the data centre cooling system performance, we derive new non-overlapped scatter plots to visualize the correlations between the temperatures and chiller utilization. All these techniques have been used successfully to monitor various time-critical thermal states in real-world large-scale production data centres and to derive cooling policies. We are starting to embed these visualization techniques into a handheld device to add mobile monitoring capability. [source] An optimal multimedia object allocation solution in multi-powermode storage systemsCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 13 2010Yingwei Jin Abstract Given a set of multimedia objects R={o1, o2, ,, ok} each of which has a set of multiple versions oi.v={Ai.0, Ai.1, ,, Ai.m}, i=1, 2, ,, k, there is a problem of distributing these objects in a server system so that user requests for accessing specified multimedia objects can be fulfilled with the minimum energy consumption and without significant degrading of the system performance. This paper considers the allocation problem of multimedia objects in multi-powermode storage systems, where the objects are distributed among multi-powermode storages based on the access pattern to the objects. We design an underlying infrastructure of storage system and propose a dynamic multimedia object allocation policy based on the designed infrastructure, which integrate and prove the optimality of the proposed policy. Copyright © 2010 John Wiley & Sons, Ltd. [source] AMP-activated protein kinase: role in metabolism and therapeutic implicationsDIABETES OBESITY & METABOLISM, Issue 6 2006Greg Schimmack AMP-activated protein kinase (AMPK) is an enzyme that works as a fuel gauge which becomes activated in situations of energy consumption. AMPK functions to restore cellular ATP levels by modifying diverse metabolic and cellular pathways. In the skeletal muscle, AMPK is activated during exercise and is involved in contraction-stimulated glucose transport and fatty acid oxidation. In the heart, AMPK activity increases during ischaemia and functions to sustain ATP, cardiac function and myocardial viability. In the liver, AMPK inhibits the production of glucose, cholesterol and triglycerides and stimulates fatty acid oxidation. Recent studies have shown that AMPK is involved in the mechanism of action of metformin and thiazolidinediones, and the adipocytokines leptin and adiponectin. These data, along with evidence that pharmacological activation of AMPK in vivo improves blood glucose homeostasis, cholesterol concentrations and blood pressure in insulin-resistant rodents, make this enzyme an attractive pharmacological target for the treatment of type 2 diabetes, ischaemic heart disease and other metabolic diseases. [source] When fish meet fish as determined by physiological sensorsECOLOGY OF FRESHWATER FISH, Issue 4 2009O. Slavík Abstract,,, Electromyogram (EMG) biotelemetry allows a description of the spatial distribution of fish together with a simultaneous measurement of individual energy consumption. Using this technique, we observed behaviour of the largest European freshwater predator, Silurus glanis, in the Elbe River, Central Europe. In total, 52 diurnal cycles and 1248 individual fish positions were recorded with 12,480 EMG records during the period from March to May 2006; 1013 fish positions with 10,130 EMG records were further used for statistical analyses. Energy consumption increased with decreasing mutual distance between specimens, an effect that occurred predominantly when both of them were simultaneously in overlapping preferred areas [core areas (CAs)] appointed within their home ranges (HRs). Furthermore, with increasing energy consumption individual's movement range in longitudinal and lateral profiles decreased; i.e., the fish were positioned within a small area. When the CAs of tested individuals did not overlap, no relationship between EMG signals and mutual distance of conspecifics was found. Our results indicate that movement activity and also social behaviour can be determined with physiological sensors. [source] Proposal and evaluation of a gas engine and gas turbine hybrid cogeneration system in which cascaded heat is highly utilizedELECTRICAL ENGINEERING IN JAPAN, Issue 3 2009Pyong Sik Pak Abstract A high-efficiency cogeneration system (CGS) is proposed for utilizing high-temperature exhaust gas (HTEG) from a gas engine (GE). In the proposed system, for making use of heat energy of HTEG, H2O turbine (HTb) is incorporated and steam produced by utilizing HTEG is used as working fluid of HTb. HTb exhaust gas is also utilized for increasing power output and for satisfying heat demand in the proposed system. Both of the thermodynamic characteristics of the proposed system and a gas engine CGS (GE-CGS) constructed by using the original GE are estimated. Energy saving characteristics and CO2 reduction effects of the proposed CGS and the GE-CGS are also investigated. It was estimated that the net generated power of the proposed CGS has been increased 25.5% and net power generation efficiency 6.7%, compared with the original GE-CGS. It was also shown that the proposed CGS could save 27.0% of energy consumption and reduce 1137 t-CO2/y, 1.41 times larger than those of GE-CGS, when a case study was set and investigated. Improvements of performance by increasing turbine inlet temperature were also investigated. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(3): 37, 45, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20708 [source] Enhanced Treatment of Trace Pollutants by a Novel Electrolytic Cell,ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 6 2006Y. Sakakibara Abstract Continuous experiments were conducted to evaluate the electrolytic performance of a novel 3-dimensional electrolytic cell consisting of granular Pt/Ti electrodes. The electric current efficiency to decompose indigotrisulfonate was approx. 96,%, while energy consumption was one to two orders of magnitude smaller than that for O3 treatment. Furthermore, the cell was successfully applied to treat trace endocrine disrupting chemicals (EDCs) and chlorinated compounds. Energy consumption was in the range of 2 to 10 Wh/m3. From these results, it was concluded that the present electrolytic cell would be a feasible alternative to conventional oxidation processes in water treatment. [source] Treatment of Process Water Containing Heavy Metals with a Two-Stage Electrolysis Procedure in a Membrane Electrolysis CellENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 2 2005R. Fischer Abstract The capability of a two-stage electrochemical treatment for the regeneration of acidic heavy-metal containing process water was examined. The process water came from sediment bioleaching and was characterized by a wide spectrum of dissolved metals, a high sulfate content, and a pH of about 3. In the modular laboratory model cell used, the anode chamber and the cathode chamber were separated by a central chamber fitted with an ion exchanger membrane on either side. The experiments were carried out applying a platinum anode and a graphite cathode at a current density of 0.1,A/cm2. The circulation flow of the process water in the batch process amounted to 35,L/h, the electrolysis duration was 5.5,h at maximum and the total electrolysis current was about 1,A. In the first stage, the acidic process water containing metals passed through the cathode chamber. In the second stage, the cathodically pretreated process water was electrolyzed anodically. In the cathode chamber the main load of dissolved Cu, Zn, Cr and Pb was eliminated. The sulfuric acid surplus of 3,4,g/L decreased to about 1,g/L, the pH rose from initially 3.0 to 4,5, but the desired pH of 9,10 was not achieved. Precipitation in the proximity to the cathode evidently takes place at a higher pH than farther away. The dominant process in the anode chamber was the precipitation of amorphous MnO2 owing to the oxidation of dissolved Mn(II). The further depletion of the remaining heavy metals in the cathodically pretreated process water by subsequent anodic treatment was nearly exhaustive, more than 99,% of Cd, Cr, Cu, Mn, Ni, Pb, and Zn were removed from the leachate. The high depletion of heavy metals might be due to both the sorption on MnO2 precipitates and/or basic ferrous sulfate formed anodically, and the migration of metal ions through the cation exchanger membrane via the middle chamber into the cathode chamber. In the anode chamber, the sulfuric acid content increased to 6,7,g/L and the pH sank to 1.7. All heavy metals contained, with the exception of Zn, were removed to levels below the German limits for discharging industrial wastewaters into the receiving water. Moreover, the metal-depleted and acid-enriched process waters could be returned to the leaching process, hence reducing the output of wastewater. The results indicated that heavy metals could be removed from acidic process waters by two-stage electrochemical treatment to a large extent. However, to improve the efficiency of metal removal and to establish the electrochemical treatment in practice, further work is necessary to optimize the operation of the process with respect to current density, energy consumption, discharging of metal precipitates deposited in the electrode chambers and preventing membrane clogging. [source] Greenhouse gas emission policies in the UK and Germany: influences and responsesENVIRONMENTAL POLICY AND GOVERNANCE, Issue 3 2002Bettina Schrader Climate change is considered to be one of the greatest environmental threats. In response to this threat, developed countries agreed in Kyoto to legally binding targets, which will reduce their atmospheric emissions. In April 1999 Germany introduced an environmental tax. At the same time the UK announced the introduction of a levy on energy consumption, from April 2001. This paper investigates the proposals from both governments and the influences upon them of a variety of institutions (NGOs, industry and business organizations). The similarities and differences between the consultation experiences, and the resulting policies, will be discussed for the two countries. Lessons are drawn applicable to the wider context of EU environmental legislation. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment [source] Design of dual-purpose membrane desalination systemsENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 3 2010Rajindar Singh Abstract Reverse osmosis (RO) and nanofiltration (NF) membrane plants are used extensively for brackish water desalination and industrial water purification. The operating range of RO plants is 60,80% product water recovery depending on the quality of raw water and feed water pretreatment. Typically, these plants operate at 75% recovery. The disposal of RO reject streams (20,40% of plant feed water) containing high concentration of salts is becoming an environmental problem. To reduce brine disposal costs and to increase product water recovery, several high-recovery energy-efficient membrane processes were analyzed. Generally speaking, a balance is required between brine volume reduction, capital and operating costs, energy consumption, and process simplicity. The analyses showed that up to 90% product water recovery can be achieved for low to medium brackish feed waters using RO/NF membrane systems with minimal feed water chemical pretreatment. The benefits of hybrid membrane systems integrated with fuel cell alternate energy systems are discussed. © 2009 American Institute of Chemical Engineers Environ Prog, 2010 [source] Ultrasonic treatment of waste activated sludgeENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 2 2006Raf Dewil Abstract Activated sludge processes are key technologies to treat wastewater. These biological processes produce huge amounts of waste activated sludge (WAS), now commonly called biosolids. Mechanical, thermal, and/or chemical WAS conditioning techniques have been proposed to reduce the sludge burden. The ultrasonic treatment of WAS is quite novel. The present paper reports on extensive investigations using an ultrasonic treatment of WAS, to study its potential to meet one or all of four objectives: (1) reduce WAS quantities; (2) achieve a better dewaterability; (3) provoke a release of soluble chemical oxygen demand (COD) from the biosolids, preferably transformed into biodegradable organics; and (4) possibly destroy the filamentous microorganisms responsible for sludge bulking. Although meeting these objectives would help to solve the problems cited, the energy consumption could be a considerable drawback: the paper will thus assess whether all or some objectives are met, and at what operational cost. A literature survey defines the occurring phenomena (cavitation) and the important operation parameters [such as frequency, duration, specific energy input (SE)]. The experiments are carried out in a batch reactor of volume up to 2.3 L. The ultrasonic equipment consisted of a generator, a converter, and a sonotrode, supplied by Alpha Ultrasonics under the brand name of Telsonic. Three different kinds of sludge were tested, with different concentrations of dry solids (DS) between approximately 3.5 and 14 g DS/L WAS. Ultrasonic energy was introduced in a continuous manner (against possible pulsed operation). The major operational parameters studied include duration of the ultrasonic treatment and specific energy input. The applied frequency was set at 20 kHz. The release of COD from the WAS phase into the filtrate phase is a function of the specific energy input with yields of nearly 30% achievable at SE values of 30,000 kJ/kg DS. A major fraction of the COD is transformed into biodegradable organics (BOD). The reduction in DS fraction of the sludge is proportional to the COD release rates. Although the DS content is reduced, the dewaterability of the sludge is not improved. This reflects itself in increased filtration times during vacuum filtration and in increased values of the capillary suction time (CST). This more difficult dewaterability is the result of considerably reduced floc sizes, offering an extended surface area: more surface water is bound (CST increases) and the filterability decreases as a result of clogging of the cake. To reach the same dryness as for the untreated cake, the required dosage of polyelectrolyte is nearly doubled when the SE of the ultrasound treatment is increased from 7500 to 20,000 kJ/kg DS. The ultrasonic reduction of filamentous WAS organisms is not conclusive and very little effect is seen at low intensities and short treatment durations. Microscopic analysis of the WAS identified the dominant presence of Actynomyces. The release of soluble COD and BOD certainly merit further research. © 2006 American Institute of Chemical Engineers Environ Prog, 2006 [source] Power efficiency of thin clientsEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 6 2010Willem Vereecken Worldwide, awareness for energy consumption is rising because of global energy production limits as well as because of environmental concerns. As the energy fraction currently consumed by ICT-related equipment is substantial (about 8 per cent of electricity consumption worldwide in the use phase) and the growth rate in this particular sector is spectacular, in the ICT sector, adequate solutions are needed to allow sustainable growth. In this paper we aim at reducing power consumption of desktop applications by applying a thin client approach and we analyse the conditions necessary. To this end, estimates on power consumptions in typical desktop scenarios and analogous thin client settings are made and analysed. The paper concludes with an experimental study on currently available equipment, to translate the generic conclusions into their current implications and trade-offs. Copyright © 2010 John Wiley & Sons, Ltd. [source] Cocaine- and amphetamine-regulated transcript (CART) peptide as an in vivo regulator of cardiac function in Rana ridibunda frogEXPERIMENTAL PHYSIOLOGY, Issue 6 2007Iliyana V. Ivanova The aim of this study was to investigate the effect of CART peptide on cardiac performance and on the physiological signalling pathways involved using Rana ridibunda frog heart preparations in vivo. The CART peptide, when injected into the venous sinus, significantly and reproducibly increased the force of frog heart contractions by up to 33.0 ± 6.4% during the first 15 min after its application but did not influence the chronotropic activity of the frog heart. The positive inotropic effect was entirely blocked by prazosin, pertussis toxin, Rp -adenosine 3,,5,-cyclic monophosphorothioate, autosauvagine 30 or metyrapone, as well as by extirpation of the pituitary gland, functional elimination of the inter-renal glands and long-lasting starvation, and was not observed on isolated heart preparations. Propranolol and double pithing were without significant effect on this phenomenon. It was concluded that: (i) CART peptide, administered to frogs in vivo, increases the force of heart contractions; (ii) this effect of the peptide is exerted via activation of the hypothalamic,pituitary,inter-renal gland axis through a corticoliberin-sensitive mechanism; (iii) CART augments the pumping function of the heart via a corticosteroid-dependent potentiation of myocardial ,1 -adrenoreceptors signalling; and (iv) prolonged food deprivation abolishes the positive inotropic effect of CART, suggesting the participation of endogenous CART in the physiological adaptation of the circulatory system to limitations of energy consumption. [source] Residential Energy Consumption: 1987 to 1997FAMILY & CONSUMER SCIENCES RESEARCH JOURNAL, Issue 3 2002Becky L. Yust The purpose of this study was to examine energy-conserving practices and consumption from 1987 to 1997 using a human ecosystem framework. Research on energy consumption and practices at the household level has been minimal in recent years. Factors that influence household energy consumption were examined, including climate, demographic characteristics of the households, housing characteristics including weatherization features and appliances, and occupant behaviors. This study was a secondary analysis of data compiled by the Energy Information Administration from the 1987, 1990, 1993, and 1997 Residential Energy Consumption Surveys and included only owner-occupied, single-family detached residences. Based on multiple regression analyses, more than 30% of the household energy consumption was accounted for by the variables representing the environments of the human ecosystem. [source] Temporal variation of energy reserves in mayfly nymphs (Hexagenia spp.) from Lake St Clair and western Lake ErieFRESHWATER BIOLOGY, Issue 10 2003J.F. Cavaletto Summary 1. We analysed changes in energy reserves (lipid and glycogen) and length,weight relationships of burrowing mayflies (Hexagenia spp.) in 1997,99 to compare an established population in Lake St Clair with a recovering population in western Lake Erie of the Laurentian Great Lakes. In addition, we measured changes in water temperature and potential food in both water columns and sediments. 2. Although overall mean values of lipid and glycogen levels of Hexagenia nymphs from Lake St Clair and western Lake Erie were not significantly different, there were differences in seasonal patterns between the two lakes. In Lake St Clair, levels were highest in early spring, declined throughout the year, and reached their lowest levels in fall during all 3 years of study. In contrast, levels in western Lake Erie were lower in spring, increased to a maximum in summer, then declined in fall. Seasonal patterns in length,weight relationships were similar to those for lipid and glycogen. 3. Total lipid as a percentage of dry weight did not increase with developmental stage of nymphs until just prior to metamorphosis and emergence from water. However, the major reserve lipid, triacylglycerols, increased systematically with development stage. In the final stage of development, triacylglycerols declined, probably as a result of energy consumption and its conversion to other biochemical components for metamorphosis and reproduction. 4. Indicators of potential food (algal fluorescence in the water column and chlorophyll a and chlorophyll a/phaeophytin ratio in sediments) suggest that Hexagenia in Lake St Clair have a food source that is benthic based, especially in early spring, whereas in western Lake Erie nymphs have a food source that is water column based and settles to the lake bottom during late spring and summer. [source] Hydrogen for the Mobility of the Future Results of GM/Opel's Well-to-Wheel Studies in North America and EuropeFUEL CELLS, Issue 3 2003U. Winter Abstract General Motors conducted two well-to-wheel studies for fundamental clarification on the question of which is the cleanest and most environmentally sustainable source of energy for the mobility of the future. In both studies the complete energy chains were analyzed from fuel production using primary energy to the actual consumption of the fuel in the car, i.e. from the well up to the wheels of the vehicle (well to wheel). The aim of the studies was to evaluate total energy consumption on the one hand and, on the other, the total greenhouse gas emissions arising between the production of a fuel and its final use to power an automobile. The results of the studies clearly show that fuel cell vehicles can greatly reduce greenhouse gas emissions from passenger cars or, if they run on hydrogen from renewable energy sources, they can eliminate them entirely. Regenerative fuels, however, will be more expensive than current products. With the fuel cell, because of its superior efficiency (35 , 45% less energy consumption well to wheel), it will be possible to keep individual mobility affordable in the future. [source] Developmental, metabolic and immunological costs of flea infestation in the common voleFUNCTIONAL ECOLOGY, Issue 6 2008Godefroy Devevey Summary 1Parasites use resources from their hosts, which can indirectly affect a number of host functions because of trade-offs in resource allocation. In order to get a comprehensive view of the costs imposed by blood sucking parasites to their hosts, it is important to monitor multiple components of the development and physiology of parasitized hosts over long time periods. 2The effect of infestation by fleas on body mass, body length growth, haematocrit, resistance to oxidative stress, resting metabolic rate and humoral immune response were experimentally evaluated. During a 3-month period, male common voles, Microtus arvalis, were either parasitized by rat fleas (Nosopsyllus fasciatus), which are naturally occurring generalist ectoparasites of voles, or reared without fleas. Then voles were challenged twice by injecting Keyhole Limpet Haemocyanin (KLH) to assess whether the presence of fleas affects the ability of voles to produce antibodies against a novel antigen. During the immune challenge we measured the evolution of body mass, haematocrit, resistance to oxidative stress and antibody production. 3Flea infestation negatively influenced the growth of voles. Moreover, parasitized voles had reduced haematocrit, higher resting metabolic rate and lower production of antibodies against the KLH. Resistance to oxidative stress was not influenced by the presence of fleas. 4During the immune challenge with KLH, body mass decreased in both groups, while the resistance to oxidative stress remained stable. In contrast, the haematocrit decreased only in parasitized voles. 5Our experiment shows that infestation by a haematophageous parasite negatively affects multiple traits like growth, energy consumption and immune response. Fleas may severely reduce the survival probability and reproductive success of their host in natural conditions. [source] Influence of temperature on hydrodynamic costs of morphological defences in zooplankton: experiments on models of Eubosmina (Cladocera)FUNCTIONAL ECOLOGY, Issue 3 2000R. Lagergren Abstract 1.,If swimming speed is correlated to fitness (e.g. by affecting food intake or the chance to evade predators) or considerable energy is expended in swimming, zooplankton wearing protruding structures (as predator defence) that significantly increase drag resistance must pay a cost for the better protection against predators that these traits imply. 2.,In an experiment with plastic models, the drag and energy consumption of swimming in two species of Eubosmina were examined. Eubosmina longispina has a typical Bosmina morphology with a low carapace and short antennule, whereas E. coregoni gibbera has a very high carapax and long antennule. 3.,At 5 °C, E. c. gibbera had 32,45% higher drag than E. longispina. At 20 °C, the difference is 20,45%. 4.,A mathematical model of swimming predicts that these differences in drag should result in 18,20 (at 5 °C) or 14,16 (at 20 °C) percentage lower speed for E. c. gibbera than for E. longispina if they use the same amount of energy in swimming. 5.,The relative difference in drag or swimming speed between the two species was highest at low Reynolds number (i.e. low speed or low temperature). These results show that hydrodynamic costs of extreme morphology may increase with decreasing temperature. 6.,The increased cost of morphological antipredator defence at low temperatures may be enlightening with regard to the role of temperature in the induction of cyclomorphic traits in zooplankton. This may be one explanation for why extreme forms of E. c. gibbera and some Daphnia are only found in the summer when water temperature is high. [source] Algorithm for determining optimum sequestration depth of CO2 trapped by residual gas and solubility trapping mechanisms in a deep saline formationGEOFLUIDS (ELECTRONIC), Issue 4 2008C. K. LIN Abstract An algorithm is proposed here for determining the optimum sequestration depth (in terms of depth corresponding to maximum net income per unit rock volume) in a saline formation for CO2 trapped by residual gas and solubility trapping mechanisms. The Peng,Robinson equation of state was used to determine the density and fugacity of sequestered CO2 and the compression energy required for CO2 injection. Geochemist's Workbench®, a commercial geochemical software package, was used to estimate CO2 solubility in groundwater. Operational costs and CO2 emissions due to compression energy consumption were estimated. A hypothetical reference case was constructed to illustrate the proposed algorithm, assuming constant values of geothermal gradient, hydrostatic pressure gradient, sweep efficiency and initial groundwater chemistry, with a depth-dependent porosity and porosity-dependent saturation of residual gas. In general, the algorithm was illustrated successfully for the hypothetical reference case and produced the following results. The depth corresponding to maximum trapping capacity was approximately 3000 m, but the depth representing maximum net income was approximately 1300 m. CO2 emissions due to compression energy consumption per unit mass of CO2 sequestration cannot be ignored, but may be <0.15, even down to a depth of 7000 m. Both the trapping capacity and net income of CO2 sequestration decreased with geothermal gradient, but the corresponding optimum depths increased with geothermal gradient. [source] The heat transfer and pressure loss characteristics of a heat exchanger for recovering latent heat (the heat transfer and pressure loss characteristics of the heat exchanger with wing fin)HEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 4 2007Kiyoshi Kawaguchi Abstract In recent years the requirement for reduction of energy consumption has been increasing to solve the problems of global warming and the shortage of petroleum resources. A latent heat recovery type heat exchanger is one of the effective methods of improving thermal efficiency by recovering latent heat. This paper described the heat transfer and pressure loss characteristics of a latent heat recovery type heat exchanger having a wing fin (fin pitch: 4 mm, fin length: 65 mm). These were clarified by measuring the exchange heat quantity, the pressure loss of heat exchanger, and the heat transfer coefficient between outer fin surface and gas. The effects of condensate behavior in the fins on heat transfer and pressure loss characteristics were clarified. Furthermore, the equations for predicting the heat transfer coefficient and pressure loss which are necessary in the design of the heat exchanger were proposed. ©2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(4): 215,229, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20154 [source] Recent Advances in White Organic Light-Emitting Materials and Devices (WOLEDs)ADVANCED MATERIALS, Issue 5 2010Kiran T. Kamtekar Abstract WOLEDs offer new design opportunities in practical solid-state lighting and could play a significant role in reducing global energy consumption. Obtaining white light from organic LEDs is a considerable challenge. Alongside the development of new materials with improved color stability and balanced charge transport properties, major issues involve the fabrication of large-area devices and the development of low-cost manufacturing technology. This Review will describe the types of materials (small molecules and polymers) that have been used to fabricate WOLEDs. A range of device architectures are presented and appraised. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||