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This paper presents a new discretization technique of the hydrodynamic energy balance model based on a finite‐element formulation. The concept of heat source lumping is introduced, and the thermal conductivity model includes the effect of varying both carrier concentrations and temperatures. The energy balance equation is formulated to account for kinetic energy as a convective flow. The new discretization method has the advantage that it allows for assembling the functions out of elementary variables available over elements instead of along element links. Therefore, theoretically, calculation of the Jacobian should be three times faster than by the classic method. Results are given for three examples. The method suffers from mathematical instabilities, but provides a good basis for future work to solve these problems.

The purpose of this paper is to search an energy balance routing in the wireless sensor networks (WSN) and lengthen the life of the networks.

To save energy in the WSN, some routing protocols search routing with the minimum total energy consumption of the network, and others reduce data redundancy by data aggregation. But if the distribution of energy consumption was not even, the energy of some nodes would be exhausted rapidly and thus the whole network would break down. Thus, an energy balance routing notion, including communication energy cost of the routing, remaining energy of communication sensors and sensor load have been involved. Then a new algorithm, mouse colony optimization and simulated annealing (SA), is advanced to solve the problem of energy balance routing in the network.

The energy balance routing, based on mouse colony optimization and SA, performs well and yields better performance than other congener algorithms.

The appointed times of the algorithm is the main limitation which increase the complexity of the algorithm.

A very useful routing in wireless sensor networks.

The new approach of energy balance routing notion, including communication energy cost of the routing, remaining energy of communication sensors and sensor load. The new algorithm, mouse colony optimization algorithm, simulated mice action, was proposed to solve the energy balance routing of the network.

The purpose of this paper is to compare well‐known technologies of sludge utilization on the basis of energy and economical balances of real processes. The calculations are based on pilot tests in the Central Waste Water Treatment Plant (CWWTP) in Prague, the biggest waste water treatment plant in the Czech Republic.

A key issue for the comparison of mass and energy flow of sludge management is the attainable level of sludge dewaterability. Results of dewatering of anaerobic digested sludge are available from real applications since most sewage plants use digesters. The existing limited knowledge about mixed raw sludge (MRS) dewaterability have driven authors to make pilot tests targeted to establishment of an attainable level of MRS dewaterability. To get as close results as possible even anaerobic stabilized sludge was dewatered and various other data were collected to obtain a comprehensive data set for energy balance of the sludge management calculation. The pilot tests took place at CWWTP in 2005. Measured data were used to calculate energy balance of a number of different sludge managements.

To produce self‐reliant combusting sludge, a dry matter content of 35‐45 per cent for MRS and 45‐55 per cent for digested sludge has to be achieved by means of dewatering and potentially drying. In recent measurements at CWWTP a dry matter content of about 33 per cent was achieved by dewatering of MRS. This value is very close to the range of the dry matter content at which a self reliant combustion can be expected.

This comparison together with investment cost analysis should be one of the most important parameters in case of design a new or revamp an old waste water treatment plant.

The paper provides results from pilot tests at CWWTP together with three different energy balances comparison.

The use of energy balance and simplified hydrodynamic models for simulating GaAs devices is investigated. The simplified hydrodynamic model predicts velocity spikes that are not present in more detailed Monte Carlo simulation results. These velocity spikes are associated with overestimation of thermal diffusion. The simplified hydrodynamic model can predict terminal currents that are significantly lower than those predicted by the energy balance model. The differences between the models are significantly greater than those observed previously for silicon devices. The main conclusion of this study is that the energy balance model is preferable to the simplified hydrodynamic model as the basis for GaAs device simulation, but the energy balance model still needs refinement to improve the agreement with more general simulation and experimental results.

The aim of this paper is to revisit the albedo for uncertainty. The albedo is considered as a fuzzy value due to some realistic reasons which they will be discussed in details. After defining an appropriate uncertain albedo by using fuzzy set theory, the related energy balance model is also redefined as a fuzzy differential equation by using the concept of fuzzy derivative.

The well-known Earth energy balance model is redefined as a fuzzy differential equation by using the concept of fuzzy derivative. Thus, instead of an ordinary differential equation, a fuzzy differential equation arises which it's solution procedure will be discussed in details.

Results indicate that the fuzzy uncertainty for albedo causes more real results after solving the fuzzy energy balance equation. Considering albedo as a fuzzy number is more realistic than considering a single certain number for albedo of a surface. This is due to this fact that the Earth's surface coverage is not crisp and the boundaries of different types of lands are not consistent. The proposed approach of this paper can help us to provide more realistic climate models and construct dynamical models which can model the albedo based on its variability.

In this paper, we defined fuzzy energy balance model as a fuzzy differential equation for the first time. We also, considered albedo as a fuzzy number which is another novel approach.

The purpose of this paper is to show a thermodynamic analysis to determine the contribution of each term of the total energy balance.

The thermodynamic analysis comprises a number of numerical simulations where some terms, typically ignored by the commonly used approximations, are removed from the total energy equation to quantify the effects in the flow and heat transfer fields. The case study is the differentially heated square cavity flow, in which the effects of work done by the pressure forces contribute significantly to the energy balance. Because local magnitudes are computed here for discussion, the dimensional form of the governing equations is preferred and a numerical model without any restrictive approximation about the role of the pressure is used.

The results show that the work of gravity forces term is in perfect balance with the work of pressure forces term, and thus, ignoring the contribution of one of them yields an incorrect solution. In addition, it is shown that the assumption of zero divergence of the Boussinesq approximation can be erroneous, even for a natural convection flow case where the temperature difference is very small.

As the flow and heat transfer governing equations are complex, simplifying assumptions are generally used; that is, the Boussinesq and low Mach number approximations. These assumptions are systematically adopted without any validation process and without considering that they modify the physical meaning of one or more of the thermodynamic quantities, particularly the pressure. This fact results in inconsistencies of the different forms of energy.

This is the first time that the terms of the total energy balance are quantified in such a way, in a differentially heated square cavity flow, which is a case study addressed by several authors.

An energy balance equation model coupled with drift‐diffusion transport equations are solved in heterojunction p‐i‐n diodes with embedded single quantum well to model hot electron effects. A detailed formulation of hot electron transport is presented. In the well, the carrier energy levels are estimated from the analytical expressions applied to a quantum well with finite height. Both bound and free carriers are modeled by Fermi‐Dirac statistics. Both size quantization and the two dimensional density of states in the well are considered. Thermionic emission is applied to the heterojunctions and quantum wells boundary. Energy transfer among the charge carriers and crystal lattice is modeled by an energy relaxation lifetime. Two sets of devices are simulated. First, the simulated kinetic energy and carrier density profiles were compared with published Monte Carlo results on an GaAs n⁺/n/n⁺ diode. Second, the current‐voltage characteristics of an embedded single quantum well AlGaAs/GaAs p‐i‐n structure was compared with measured data. Both comparisons are satisfactory and demonstrate the usefulness of the model for studying quantum well structures.

The purpose of this paper is to present an analytical approximate technique to solve nonlinear conservative oscillator based on the He’s energy balance method (improved version recently presented by Khan and Mirzabeigy). The method is illustrated by solving double well Duffing oscillator.

The Duffing equation with a double-well potential (with a negative linear stiffness) is an important model of a mass particle moving in a symmetric double well potential. This form of the equation also appears in the transverse vibrations of a beam when the transverse and longitudinal deflections are coupled (Thompsen, 2003).

The approximate solutions obtained by the present technique have good agreement with the numerical solution and also provide better results than other existing methods.

The results are more accurate than those obtained by other existing methods. The relative errors obtained by the present paper are less than those obtained by other existing methods. Therefore, the present technique is very effective and convenient for solving nonlinear conservative oscillator.

In this extract from his paper, Professor Hervey discusses some of the mechanisms which may be responsible for maintaining energy balance and normal body weight.

The purpose of this study was to determine body composition, energy balance and tendencies towards eating disorders of female competitive athletes in two countries, USA and Greece. Data were collected using similar methodology in both countries during the non‐competitive (training) and the competitive seasons. Forty‐two athletes and 11 controls in the USA and 35 athletes and ten controls in Greece participated in the study. Comparison of the results between the countries showed that US athletes weighed more than Greek athletes but there was no significant difference in the percentage of body fat between the two groups. No significant differences were found in the energy intakes between athletes in either country. Athletes appeared to be in negative energy balance (‐380 to ‐580 kcals daily) in both seasons, in both countries.