Amount Of Available Energy Research Articles

Investigation of an Energy Efficient Hydraulic Propulsion System for a Railway Machine

Many railway construction and maintenance machines have large masses and perform repetitive working cycles with frequent stops that require precise positioning. For these reasons, a hydraulic propulsion system is a convenient choice. Common existing solutions make use of valve-controlled hydraulic circuits where inefficient fluid throttling takes place. Most of the time, dissipative braking is realized resulting in a remarkable quantity of available energy being wasted (up to 36 kJ of kinetic energy is available in the reference application). Additionally, the machine's automated positioning is a critical aspect. On some commercialized solutions, an overshoot of the desired final position is commonplace requiring a reverse motion in order to match the location of the desired working point. This is a negative characteristic as it introduces unnecessary fuel consumption and slows down productivity. Moreover, consideration of the limited adhesion in the wheel/rail interface is of critical importance. The propulsion system needs to be capable of differentiating the tractive or the braking torques between the driven axles. To this end, the paper proposes and analyzes a displacement-controlled (DC) propulsion system for a railway maintenance machine. The target is the removal of the fluid throttling mentioned above by defining an efficient hydraulic system. The ability to recover energy via regenerative breaking becomes a key process in improving the global machine efficiency. Simultaneously, an implementable control strategy is required for the proposed architecture to prevent overshoot of the desired position while stopping. To that end, this paper presents the mathematical model of the proposed layout used to simulate the system's behavior in order to confirm proper functioning. This work concludes with a discussion and definition of future improvements.

Cooperative Topology Control with Adaptation for improved lifetime in wireless sensor networks

Topology control algorithms allow each node in a wireless multi-hop network to adjust the power at which it makes its transmissions and choose the set of neighbors with which it communicates directly, while preserving global goals such as connectivity or coverage. This allows each node to conserve energy and contribute to increasing the lifetime of the network. In this paper, we consider (i) both the energy costs of communication as well as the amount of available energy at each node, (ii) the realistic situation of varying rates of energy consumption at different nodes, and (iii) the fact that co-operation between nodes, where some nodes make a sacrifice by increasing energy consumption to help other nodes reduce their consumption, can be used to extend network lifetime. This paper introduces a new distributed topology control algorithm, called the Cooperative Topology Control with Adaptation (CTCA), based on a game-theoretic approach that maps the problem of maximizing the network’s lifetime into an ordinal potential game. We prove the existence of a Nash equilibrium for the game. Our simulation results indicate that the CTCA algorithm extends the life of a network by more than 50% compared to other algorithms. We also study the performance of the distributed CTCA algorithm in comparison to an optimal centralized algorithm as a function of the communication ranges of nodes and node density.

Controlling directionality and the statistical regime of the random laser emission

Unlike a conventional optical cavity laser, a random laser system is generally characterized by a nondirectional output emission. In this work we report an experimental and theoretical study on the angular properties of the random laser emission and its dependence on the diffusive properties of the sample and the spatial gain profile, showing the possibility of controlling it by the total amount of available energy. We show that the directional characteristics are associated with the statistical regime of fluctuations in the emission spectrum and, in particular, with a L\'evy statistical regime. A model based on a phase-insensitive feedback mechanism has been used in order to explain the experimental data and two different L\'evy subregimes have been identified.

Contrasting characteristics of the surface energy balance between the urban and rural areas of Beijing

A direct comparison of urban and rural surface energy balances, as well as a variety of other variables including incoming shortwave/longwave radiation and aerosol optical depth, is conducted for the Beijing metropolitan area. The results indicate that, overall, the urban area receives a smaller amount of incoming shortwave radiation but a larger amount of incoming longwave radiation. However, comparisons in the aerosol optical depth and cloud fraction at the two locations suggest that neither aerosol optical depth nor cloud fraction alone can explain the difference in the incoming shortwave radiation. The urban-rural differences in the incoming longwave radiation are unlikely to be caused by the presence of more abundant greenhouse gases over the urban area, as suggested by some previous studies, given that water vapor is the most dominant greenhouse gas and precipitable water is found to be less in urban areas. The higher incoming longwave radiation observed over the urban area is mostly likely due to the higher temperatures of the ambient air. The urban area is also found to always produce higher sensible heat fluxes and lower latent heat fluxes in the growing season. Furthermore, the urban area is associated with a larger amount of available energy (the sum of sensible and latent heat fluxes) than the rural area, except in May and October when evapotranspiration in the rural area significantly exceeds that in the urban area. This study provides observational evidence of urban-rural contrasts in relevant energy-balance components that plausibly arise from urban-rural differences in atmospheric and land-surface conditions.

天然气管网压力能利用技术分析

天然气管网蕴含着巨大的压力能资源可供开发利用，利用㶲分析理论计算了天然气管网可用能量，当管网天然气由压力10 MPa、温度293.15 K，降到压力0.8 MPa、温度210.15 K时，可回收压力能达到356.63 kJ/kg。对于年输气能力1500 × 108 m3的天然气管网，可回收能量相当于120 × 104 kW的电站一年的发电量。介绍了天然气管网压力能利用的各种方式，分析了压力能利用技术存在的问题。 The natural gas pipeline network has great potential pressure energy which has not been devel-oped yet. The energy analysis theory is used to calculate the total amount of available energy of the natural gas pipeline network. When the pressure and the temperature of the pipeline network are reduced from 10 MPa to 0.8 MPa and from 293.15 K to 210.15 K, respectively, the recyclable energy can reach 356.63 kJ/kg. For the natural gas pipeline network having annual gas transmission capacity of 1500 × 108 m3, the recyclable energy is equivalent to the annual power generating ca-pacity of 120 × 104 kW. This paper introduces various ways that the natural gas pipeline network pressure can use, and analyzes the existing problems of pressure energy utilization technology.

More individuals drive the species energy–area relationship in an experimental zooplankton community

The shape of the species–area relationship (SAR) often varies with the amount of available energy; SARs from high‐energy habitats typically have higher intercepts and steeper slopes than SARs from low‐energy habitats. Such patterns are often assumed to result from a shift in the mechanisms of coexistence between high and low energy habitats. However, a plausible but unexplored alternative mechanism emerges from proportional sampling, if there are simply more individuals in larger or more productive habitats, without the need to invoke differing coexistence mechanisms. Here, we examined proportional versus disproportional responses of a diverse assemblage of freshwater zooplankton to manipulations of experimental pond size and energy inputs. We found that higher energy treatments had higher species richness in large, but not small, ponds, leading to a steeper SAR with higher energy input. The total abundances of individuals also increased with energy in large, but not small ponds. By using a sample‐independent rarefaction technique (probability of interspecific encounter), we found that SAR patterns resulted from changes in the total, but not relative, abundance of individuals, and thus proportional, rather than disproportional, responses of species. Overall, our results emphasize the need to consider how both the total and relative abundances of species respond to ecological drivers such as energy and area before inferring the underlying mechanisms that lead to biodiversity patterns. Further, our results may implicate a proportionally smaller influence of energy on patterns of biodiversity when habitats are destroyed.

An inner membrane cytochrome required only for reduction of high redox potential extracellular electron acceptors.

ABSTRACTDissimilatory metal-reducing bacteria, such as Geobacter sulfurreducens, transfer electrons beyond their outer membranes to Fe(III) and Mn(IV) oxides, heavy metals, and electrodes in electrochemical devices. In the environment, metal acceptors exist in multiple chelated and insoluble forms that span a range of redox potentials and offer different amounts of available energy. Despite this, metal-reducing bacteria have not been shown to alter their electron transfer strategies to take advantage of these energy differences. Disruption of imcH, encoding an inner membrane c-type cytochrome, eliminated the ability of G. sulfurreducens to reduce Fe(III) citrate, Fe(III)-EDTA, and insoluble Mn(IV) oxides, electron acceptors with potentials greater than 0.1 V versus the standard hydrogen electrode (SHE), but the imcH mutant retained the ability to reduce Fe(III) oxides with potentials of ≤−0.1 V versus SHE. The imcH mutant failed to grow on electrodes poised at +0.24 V versus SHE, but switching electrodes to −0.1 V versus SHE triggered exponential growth. At potentials of ≤−0.1 V versus SHE, both the wild type and the imcH mutant doubled 60% slower than at higher potentials. Electrodes poised even 100 mV higher (0.0 V versus SHE) could not trigger imcH mutant growth. These results demonstrate that G. sulfurreducens possesses multiple respiratory pathways, that some of these pathways are in operation only after exposure to low redox potentials, and that electron flow can be coupled to generation of different amounts of energy for growth. The redox potentials that trigger these behaviors mirror those of metal acceptors common in subsurface environments where Geobacter is found.

Net radiation estimated by remote sensing in Cerrado areas in the Upper Paraguay River Basin

The Cerrado is a heterogeneous landscape which is shrinking due to deforestation, giving rise to managed ecosystems. The land cover changes alter net radiation (Rn), which determines the quantity of available energy to the energy balance partition. The objectives of this study were (1) to determine the spatial pattern of the vegetation indices, albedo, and land surface temperature (LST) and (2) to evaluate the Rn estimated by Landsat 5 Thematic Mapper (TM) images over Cerrado areas in the Upper Paraguay River Basin. We estimated the vegetation indices, albedo, LST, and Rn of five selected vegetation types. The values estimated by Landsat 5 TM images had seasonal variations with higher values of the vegetation indices and lower values of the albedo and the LST during the wet season. The riparian and Cerrado strictu sensu had higher values of vegetation indices and lower albedo and LST than grasslands. The Rn estimated by Landsat 5 TM images was highly correlated with the measured Rn. The Rn had a seasonal pattern, following the solar radiation, with higher values during the wet season and varied spatially with higher values in the riparian forest and Cerrado strictu sensu and lower in the grasslands. This study showed the applicability of the Landsat 5 TM images to estimate Rn, which can help to understand the heterogeneity in the study area.

무선 센서네트워크에서 다종 센서(Different Types of Sensors)가 미치는 영향에 대한 분석

In this paper, we constructed a sensor network environment where various sensors are used. Then, we evaluated the performance when this environment adopted existing clustering algorithms that are designed for only single type sensors network. In our experiments, we considered two different types of the networks. In the first, all nodes are equipped with identical sensors. In the second, all nodes are equipped with three different types of sensors. We measured performance variations of several clustering schemes in accordance with sensor data accuracy, sensor node ∙제1저자 : 최동민 ∙교신저자 : 김성열 ∙투고일 : 2014. 8. 5, 심사일 : 2014. 8. 17, 게재확정일 : 2014. 9. 3. * 조선대학교 자유전공학부(Div. of Undeclared Majors, Chosun University) ** 조선대학교 컴퓨터공학과(Def. of Computer Eng., Chosun University) *** 울산과학대학교 컴퓨터정보학부(School of Information Technology, Ulsan college) 76 Journal of The Korea Society of Computer and Information September 2014 resource depletion timing, amount of available energy, node isolation ratio, and network lifetime. According to our performance analysis, we proved that existing clustering algorithms are partially inefficient to maintain the various-sensor network. Consequently we suggest that a new algorithm is required to take aim at the various sensor network. ▸

Study on the supply capacity of crop residue as energy in rural areas of Heilongjiang province of China

Abstract Heilongjiang is the most northeastern province of China. The climate of Heilongjiang consists of very cold winters, leading to large energy demands for space heating by local residents. Rich food crop yields in Heilongjiang results in large amounts of crop residues. To fully accommodate rural energy demand and facilitate the effective utilization of crop residues, this study builds a mathematical model of supply capacity of crop residues as energy, then, based on the data from a field survey and literature review, calculates the local annual effective heat demands for living, the supply rates for effective heat of different crop residue utilization patterns, and the supply capacities of crop residues as energy in rural areas of Heilongjiang. Results show that the supply capacity of traditional direct burning of crop residues is less than 1, indicating that direct burning of crop residues cannot fully supply rural living heat demands. The supply capacity of densification is more than 1.6, indicating that introducing densification can not only achieve full supply for rural living heat demands, but also result in a large proportion of crop residues remaining for other uses. Because part of the crop residues is converted to products other than gas, dry distillation can only supply 55% of the rural living heat demands. Introducing efficient technologies of crop residue utilization for energy in rural areas of Heilongjiang can make the available amount of energy from crop residues larger than the amount of energy demand. This study found that the combination of densification and dry distillation of crop residues can be used as a high-efficiency centralized supplement of living heat, achieving multiple benefits such as use of alternatives to fossil fuel energy, economic development, environment protection, and improvement in quality of life.

Co-pyrolysis of swine manure with agricultural plastic waste: Laboratory-scale study

Manure-derived biochar is the solid product resulting from pyrolysis of animal manures. It has considerable potential both to improve soil quality with high levels of nutrients and to reduce contaminants in water and soil. However, the combustible gas produced from manure pyrolysis generally does not provide enough energy to sustain the pyrolysis process. Supplementing this process may be achieved with spent agricultural plastic films; these feedstocks have large amounts of available energy. Plastic films are often used in soil fumigation. They are usually disposed in landfills, which is wasteful, expensive, and environmentally unsustainable. The objective of this work was to investigate both the energetics of co-pyrolyzing swine solids with spent plastic mulch films (SPM) and the characteristics of its gas, liquid, and solid byproducts. The heating value of the product gas from co-pyrolysis was found to be much higher than that of natural gas; furthermore, the gas had no detectable toxic fumigants. Energetically, sustaining pyrolysis of the swine solids through the energy of the product gas could be achieved by co-pyrolyzing dewatered swine solids (25%m/m) with just 10% SPM. If more than 10% SPM is used, the co-pyrolysis would generate surplus energy which could be used for power generation. Biochars produced from co-pyrolyzing SPM and swine solid were similar to swine solid alone based on the surface area and the 1H NMR spectra. The results of this study demonstrated the potential of using pyrolysis technology to manage two prominent agricultural waste streams (SPM and swine solids) while producing value-added biochar and a power source that could be used for local farm operations.

A Joint Duty-Cycle and Transmission Power Management for Energy Harvesting WSN

In this paper, we propose a global power management approach for energy harvesting sensor nodes. Our approach is based on a joint duty-cycle optimization and transmission power control. By simultaneously adapting both parameters, the node can maximize the number of transmitted packets while respecting the limited and time-varying amount of available energy. We obtain a high-packet delivery by using an original predictive transmission power control that can efficiently adapt the transmission power to the wireless channel conditions. To accurately model the wireless channel and the node communication hardware, a waveform-level radio frequency simulator has been developed. Simulation results show 6.5 times improvement in energy efficiency and a packet reception ratio which is 9 times more efficient than a recently published technique. A 15% increase in energy efficiency, with respect to a fixed transmission power configuration, has also been observed. Finally, the global power management strategy has been validated on a real wireless sensor networks platform. Experimental results are very similar to those obtained in simulations, and thus confirm the efficiency of our power management approach.

Energía del futuro: bioalcoholes a partir de Residuos Sólidos Urbanos (RSU)

Rev.esc.adm.negEl presente artículo tiene como objetivo presentar un panorama ambiental, técnico y económico de la producción de bioalcohol, a partir de la Fracción Orgánica de Residuos Sólidos Urbanos (FORSU), tema que ha sido trabajado en investigaciones conjuntas con la Universidad de Castilla La Mancha (UCLM-España) y complementado con otros desarrollos realizados a través de la línea de investigación en Residuos Sólidos de la Universidad EAN, con el apoyo de estudiantes de especialización tanto en gestión de residuos sólidos, como en finanzas y negocios internacionales.El aprovechamiento no convencional de los Residuos Sólidos Urbanos (RSU), y en particular, para las condiciones de América Latina en donde más del 50% de los RSU corresponden a residuos de características orgánicas, termina siendo una posibilidad para agregar valor, generar crecimiento económico y crear condiciones de trabajo dignas para las personas vinculadas al aprovechamiento informal de residuos. Por ello, aprovechando el potencial de la biotecnología que ofrece diversas opciones para la generación de energías renovables, se busca abordar la producción de bioetanol a partir de procesos biológicos de metabolización de la materia orgánica mediante fermentación.En este artículo se presentará inicialmente, el contexto global de la producción de biocombustibles en Colombia, para posteriormente presentar el desarrollo de una fase preliminar a escala de laboratorio para la obtención de bioalcohol mediante una unidad de fermentación anaerobia experimental. Posteriormente se mencionarán los elementos económicos y financieros relativos a la implementación de este tipo de tecnologías y que por consiguiente podrían afectar el desarrollo a escala industrial de dicho proceso. Los resultados permitirán evaluar la viabilidad técnica y económica, al menos en una etapa preliminar, de implementación de este tipo de procesos en Colombia.

A Fine-grained Approach for Power Consumption Analysis and Prediction

Power consumption has became a critical concern in modern computing systems for various reasons including financial savings and environmental protection. With battery powered devices, we need to care about the available amount of energy since it is limited. For the case of supercomputers, as they imply a large aggregation of heavy CPU activities, we are exposed to a risk of overheating. As the design of current and future hardware is becoming more and more complex, energy prediction or estimation is as elusive as that of time performance. However, having a good prediction of power consumption is still an important request to the computer science community. Indeed, power consumption might become a common performance and cost metric in the near future. A good methodology for energy prediction could have a great impact on power-aware programming, compilation, or runtime monitoring. In this paper, we try to understand from measurements where and how power is consumed at the level of a computing node. We focus on a set of basic programming instructions, more precisely those related to CPU and memory. We propose an analytical prediction model based on the hypothesis that each basic instruction has an average energy cost that can be estimated on a given architecture through a series of micro-benchmarks. The considered energy cost per operation includes both the overhead of the embedding loop and associated (hardware/software) optimizations. Using these precalculated values, we derive a linear extrapolation model to predict the energy of a given algorithm expressed by means of atomic instructions. We then use three selected applications to check the accuracy of our prediction method by comparing our estimations with the corresponding measurements obtained using a multimeter. We show a 9.48% energy prediction on sorting.

An energy aware algorithm for OLSR clustering

One of the important aspects of a mobile ad hoc network (MANET) is the limitation of the amount of available energy and the network lifetime. The tremendous amount of using mobile nodes in wireless communication medium makes energy efficiency a fundamental requirement for MANETs. In this paper, we propose a novel energy aware clustering algorithm for the optimized link state routing (OLSR) routing protocol. This algorithm takes into account the node density and mobility and gives major improvements regarding the number of elected cluster heads. Our objective is to elect a reasonable number of cluster heads that will serve for hierarchical routing based on OLSR. The proposed algorithm aims to increase the network lifetime by considering the ad hoc residual energy while taking routing decisions. It also optimizes the delay of carried flows by adopting a selective forwarding approach based on a hierarchical routing model.

A simple model for spatial disaggregation of evaporative fraction: Comparative study with thermal sharpened land surface temperature data over India

Evaporative fraction (EF) is a measure of the amount of available energy at the earth surface that is partitioned into latent heat flux. The currently operational thermal sensors like the Moderate Resolution Imaging Spectroradiometer (MODIS) on satellite platforms provide data only at 1000 m, which constraints the spatial resolution of EF estimates. A simple model (disaggregation of evaporative fraction (DEFrac)) based on the observed relationship between EF and the normalized difference vegetation index is proposed to spatially disaggregate EF. The DEFrac model was tested with EF estimated from the triangle method using 113 clear sky data sets from the MODIS sensor aboard Terra and Aqua satellites. Validation was done using the data at four micrometeorological tower sites across varied agro‐climatic zones possessing different land cover conditions in India using Bowen ratio energy balance method. The root‐mean‐square error (RMSE) of EF estimated at 1000 m resolution using the triangle method was 0.09 for all the four sites put together. The RMSE of DEFrac disaggregated EF was 0.09 for 250 m resolution. Two models of input disaggregation were also tried with thermal data sharpened using two thermal sharpening models DisTrad and TsHARP. The RMSE of disaggregated EF was 0.14 for both the input disaggregation models for 250 m resolution. Moreover, spatial analysis of disaggregation was performed using Landsat‐7 (Enhanced Thematic Mapper) ETM + data over four grids in India for contrasted seasons. It was observed that the DEFrac model performed better than the input disaggregation models under cropped conditions while they were marginally similar under non‐cropped conditions.

Feed energy evaluation for growing pigs.

Pigs require energy for maintenance and productive purposes, and an accurate amount of available energy in feeds should be provided according to their energy requirement. Available energy in feeds for pigs has been characterized as DE, ME, or NE by considering sequential energy losses during digestion and metabolism from GE in feeds. Among these energy values, the NE system has been recognized as providing energy values of ingredients and diets that most closely describes the available energy to animals because it takes the heat increment from digestive utilization and metabolism of feeds into account. However, NE values for diets and individual ingredients are moving targets, and therefore, none of the NE systems are able to accurately predict truly available energy in feeds. The DE or ME values for feeds are important for predicting NE values, but depend on the growth stage of pigs (i.e., BW) due to the different abilities of nutrient digestion, especially for dietary fiber. The NE values are also influenced by both environment that affects NE requirement for maintenance (NEm) and the growth stage of pigs that differs in nutrient utilization (i.e., protein vs. lipid synthesis) in the body. Therefore, the interaction among animals, environment, and feed characteristics should be taken into consideration for advancing feed energy evaluation. A more mechanistic approach has been adopted in Denmark as potential physiological energy (PPE) for feeds, which is based on the theoretical biochemical utilization of energy in feeds for pigs. The PPE values are, therefore, believed to be independent of animals and environment. This review provides an overview over current knowledge on energy utilization and energy evaluation systems in feeds for growing pigs.

Energetic cost of learning and memory can cause cognitive impairment in honeybees

The energetic cost of cognitive functions can lead to either impairments in learning and memory, or to trade-offs with other functions, when the amount of available energy is limited. However, it has been suggested that, under such conditions, social groups such as honeybees might be able to ward off cognitive impairments in individual bees by adjusting resource allocation at the colony level. Using two complementary experiments, one that tests the effect of learning on subsequent energetic state and survival, and another that tests the effect of energetic state on learning and retention, we show that individual bees pay a significant energetic cost for learning and therefore suffer from significant cognitive deficits under energetic stress. We discuss the implications of such cognitive impairments for the recent observations of bees disappearing from their colonies as well as for social life in general.

Taxonomically and functionally diverse microbial communities in deep crystalline rocks of the Fennoscandian shield

Microbial life in the nutrient-limited and low-permeability continental crystalline crust is abundant but remains relatively unexplored. Using high-throughput sequencing to assess the 16S rRNA gene diversity, we found diverse bacterial and archaeal communities along a 2516-m-deep drill hole in continental crystalline crust in Outokumpu, Finland. These communities varied at different sampling depths in response to prevailing lithology and hydrogeochemistry. Further analysis by shotgun metagenomic sequencing revealed variable carbon and nutrient utilization strategies as well as specific functional and physiological adaptations uniquely associated with specific environmental conditions. Altogether, our results show that predominant geological and hydrogeochemical conditions, including the existence and connectivity of fracture systems and the low amounts of available energy, have a key role in controlling microbial ecology and evolution in the nutrient and energy-poor deep crustal biosphere.

Energy utilization and heat production of embryos from eggs originating from young and old broiler breeder flocks

Two experiments were conducted to study the interaction between breeder age and egg size on the energy utilization (experiment 1) and heat production (experiment 2) of broiler embryos. In experiment 1, a total of 4,800 Ross-308 hatching eggs from 2 breeder ages (29 and 53 wk of age, or young and old) and, within each age, 2 egg sizes (57 to 61 g and 66 to 70 g, or small and large) were used. In experiment 2, a total of 240 Ross-308 hatching eggs from 2 breeder flocks at 29 (young) and 53 (old) wk of age, and which were selected from the same egg weight range (58 to 61 g), were tested in 2 replicate chambers. In experiment 1, it was shown that the amount of yolk relative to albumen was higher in the old flock eggs, and this effect was more pronounced in the large eggs. The old flock eggs, especially the larger egg size, contained more energy as a result of a greater yolk size. Energy utilization of the embryos was positively related to yolk size and the amount of energy transferred to yolk-free body (YFB) was largely determined by the available egg energy. The efficiency of converting egg energy into chick body energy (E(YFB)) was equal for both egg sizes and both breeder age groups. Chick YFB weight of young and old flock eggs was equal. However, dry YFB weight of chicks from old flock eggs was higher than in chicks from young flock eggs, which was associated with more protein and fat content and thus more energy accumulated into YFB. As a consequence, embryos derived from old flock eggs produced more heat from d 16 of incubation onward than those of the young flock eggs. In conclusion, the higher energy deposition into chick YFB of old flock eggs, leading to higher embryonic heat production, is the result of a higher amount of available energy in the egg and is not due to changes in E(YFB).