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Various recently proposed biomass fuels are reviewed from the point of view of their safety. Many biomass materials are proposed for use as fuels, such as refuse derived fuel (RDF), wood chips, coal-wood mixtures, etc. However, these fuels have high energy potentials and can cause fires and explosions. We have experienced many such incidents. It is very difficult to extinguish fires in huge piles of biomass fuel or storage facilities. Here current studies on heat generation for these materials and proposed evaluation methods for these new developing materials in Japan are introduced, which are consistent with measurements using highly sensitive calorimeters such as C80, or TAM, and gas emission tests. The highly sensitive calorimeters can detect small heat generation between room temperature and 80 °C, due to fermentation or other causes. This heat generation sometimes initiates real fires, and also produces combustible gases which can explode if fuel is stored in silos or indoor storage facilities.

A systematic method to calculate anharmonic force constants of crystals is presented. The method employs the direct-method approach, where anharmonic force constants are extracted from the trajectory of first-principles molecular dynamics simulations at high temperature. The method is applied to Si where accurate cubic and quartic force constants are obtained. We observe that higher-order correction is crucial to obtain accurate force constants from the trajectory with large atomic displacements. The calculated harmonic and anharmonic force constants are, then, combined with the Boltzmann transport equation (BTE) and non-equilibrium molecular dynamics (NEMD) methods in calculating the thermal conductivity. The BTE approach successfully predicts the lattice thermal conductivity of bulk Si, whereas NEMD shows considerable underestimates. To evaluate the linear extrapolation method employed in NEMD to estimate bulk values, we analyze the size dependence in NEMD based on BTE calculations. We observe strong nonlinearity in the size dependence of NEMD in Si, which can be ascribed to acoustic phonons having long mean-free-paths and carrying considerable heat. Subsequently, we also apply the whole method to a thermoelectric material Mg2Si and demonstrate the reliability of the NEMD method for systems with low thermal conductivities.

SummaryAn electric vehicle has more electronic parts than a gasoline‐powered vehicle. Not only the control circuits but also the driving circuits of electric vehicles are electrical, in contrast to those of gasoline‐powered vehicles. This means that there is a higher possibility of malfunctions in an electric vehicle due to electromagnetic disturbances caused by a lightning stroke. Therefore, it is important to establish lightning protection methodologies for electric vehicles. To clear up with the mechanisms whereby the lightning current following through the vehicle body and some other parts causes the malfunctions, it is important to clarify the transient magnetic fields and current distributions in electric vehicles. In this paper, the transient magnetic fields and the current distributions in an electric vehicle are simulated by the FDTD method, and the probability of lightning damage is discussed.

Abstract In order to improve the accuracy, validity, reliability and reproducibility of reported power conversion efficiencies for solar cells, the journal, Solar Energy Materials and Solar Cells (SOLMAT), wishes to define how power conversion efficiencies should be reported. This expands upon what is specified in our Guide for Authors. This editorial also serves as a guide on how efficiency data should be checked within the reporting laboratory before sending cells or materials for testing at an independent laboratory. The threshold where the accuracy of efficiency values is important to the journal is whenever power conversion efficiencies require external quantum efficiencies (EQE) values above 50% over a large range of wavelengths or when reported power conversion efficiencies exceed 2.5%. Extra care should be taken in submitted manuscripts to document the measurement's quality, relevance and independent verification.

Abstract The clathrate hydrate formation at the interface between liquefied carbon dioxide (CO 2 ) and liquid water is one of the key processes in the course of direct CO 2 disposal into deep seas—an option to mitigate the emission of CO 2 into the atmosphere. Eight different models have been proposed so far on the formation and metabolic self-preservation of a hydrate film at the interface and also the mass transfer of CO 2 across the hydrate film. This paper reviews those rival models one by one and illustrates how they are discrepant. Each model is critically examined, and if any, its weakness in physical reality or mathematical formulation is pointed out. The state of the art of hydrate-film modeling thus revealed suggests the necessity of more careful consulting of pertinent experimental observations to establish our physical view about hydrate films, which should serve as the base of any further work on hydrate-film modeling.

AbstractVery high photocurrent densities of up to 80 mA/cm2, observed at H2‐evolving p‐Si electrodes having high electric resistivity under AM1 (100 mW/cm2) illumination, are caused by the electron injection from the back side metal into the conduction band of p‐Si.

A shell-and-tube absorber and an ammonia absorption refrigeration (AAR) system were constructed to study falling film absorption on a horizontal tube. An empirical and numerical combined method (ENCM) was developed to estimate the actual falling film thickness using parametric analysis with a simplified mathematical falling film model and experimental results. Numerical and experimental studies showed that the simplified mathematical falling film model has an exact physical response about ammonia absorption process in the absorber. The temperature difference of solution decreases with the increasing inlet coolant temperature. The heat transfer performance of a real type shell-and-tube absorber with the AAR system is a more sensitive function of the coolant inlet temperature than the solution inlet temperature. The ENCM developed in the present study can be used to estimate the actual thickness of a falling film along a horizontal tube in the shell-and-tube absorber of the AAR system, which is very difficult to measure experimentally. The ammonia absorption rate decreases with inlet temperature of a weak ammonia solution and inlet coolant temperature.

Abstract published in Advance ACS Abstracts, April 1, 1995. 0022-365419512099-7 1 14$09.0010 oscillator approach will account for guest-water interactions as well as effects of guest movements on the chemical potential of water. In this work we extend these studies to simplified models of some larger molecules filling the large cavity of structure I. As in previous studies guest molecules are still modeled as spherical Lennard-Jones 12-6 particles. Chosen parameters correspond to previously published parameters applied to represent proper- ties of methane, ethane, ethylene, and carbon dioxide. Calcula- tions have been performed for several temperatures in the region of experimentally measured equilibrium between hydrate and ice, Le., up to a temperature of 273.15 K. A brief summary of the theory is given in section 2. The results obtained from the harmonic oscillator approach and the single-particle integrations are summarized in section 3. Cal- culated dissociation pressures for hydrate in equilibrium with ice are presented in section 4 and compared to experimental data. In section 5 we extrapolate these data to the region of hydrate in equilibrium with liquid water and compare derived results with experimental data. In section 6 we present some calculations for binary mixtures. Our conclusions are given in section 7.