Energetic Evaluation of Biomass Originating from Forest Waste by Bomb Calorimetry

Calorific values and flammability changes during a year for forest waste originating from silviculture task in Galicia (NW Spain) are reported. These waste materials are becoming to be used as alternative fuels. The present study was made on several hardwood forest species. These forest species occupy nowadays approximately 30% of the total forest surface of Galicia. Calorific values were measured by static bomb calorimeter in an oxygen atmosphere. Flammability was determined using a standard epiradiator. Simultaneously, some other parameters such as elementary chemical composition, heavy metal contents, moisture, density, ash percentage after combustion in the bomb, and main bioclimatic characteristics, were also determined. This revised version was published online in July 2006 with corrections to the Cover Date.     

陕西关中农田螽斯群落结构及生物量研究

对陕西关中农田螽斯群落结构及生物量进行了研究 .结果表明 ,陕西关中农田有 1 0种螽斯 ,其中 5种属于螽斯科 .根据螽斯种类分布 ,可以把关中农田螽斯群落分为 2群 5类 ,螽斯群落种类丰富度和多样性指数在 6— 8月最高 ,晚期优势种不明显 ,中华寰螽和暗褐蝈螽是早期优势种类 ,它们也占整个螽斯种类数量的 81 .35 % ,占总生物量的 86 .9% .     

Simultaneous Laser-Induced Fluorescence Imaging of Unburnt and Reacting Areas in Combustion Fields Using a KrF Excimer Laser

Simultaneous two-dimensional imaging of an unburnt area and a reacting area was performed using laser-induced fluorescence. Acetone was added to fuel as a tracer, and OH radical was used as a marker of the reacting area. A narrow band tunable KrF excimer laser (248 nm) was employed to excite acetone and OH simultaneously. Two intensified CCD cameras with different wavelength filters were used to detect these two kinds of species respectively. Detecting 294-314 nm (A-X (3, 2), etc.) for OH and 335-410 nm for acetone, we obtained images of each species without interference of a signal from the other. The method was also successfully applied to flames in a pressurized combustion chamber under the pressure of 0.5 MPa.     

Influence of chemical composition and sequence length on the transport properties of proton exchange membranes

One of the integral parts of the fuel cell is the proton exchange membrane. Our research group has been engaged in the past few years in the synthesis of several sulfonated poly(arylene ether) random copolymers. The copolymers were varied in both the bisphenol structure as well as in the functional groups in the backbone such as sulfone and ketones. To compare the effect of sequence length, multiblock copolymers based on poly(arylene ether sulfone)s were synthesized. This paper aims to describe our investigation of the effect of chemical composition, morphology, and ion exchange capacity (IEC) on the transport properties of proton conducting membranes. The key properties examined were proton conductivity, methanol permeability, and water self diffusion coefficient in the membranes. It was observed that under fully hydrated conditions, proton conductivity for both random and block copolymers was a function of IEC and water uptake. However, under partially hydrated conditions, the block copolymers showed improved proton conductivity over the random copolymers. The proton conductivity for the block copolymer series was found to increase with increasing block lengths under partially hydrated conditions. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2226–2239, 2006     

Preparation of solid alkaline fuel cell binders based on fluorinated poly(diallyldimethylammonium chloride)s [poly(DADMAC)] or poly(chlorotrifluoroethylene‐co‐DADMAC) copolymers

A membrane or an electrode binder to be used in a solid alkaline fuel cell (SAFC) needs to (i) be insoluble in both aqueous solutions and the required fuels, and (ii) exhibit an hydroxide ion conductivity. To achieve these goals, two pathways were employed: (i) one consists of the radical copolymerization of diallyldimethylammonium chloride (DADMAC) with chlorotrifluoroethylene (CTFE) while (ii) the other one is based on the counter‐ion exchange of a poly(DADMAC) by fluorinated anions. First, the radical copolymerization of CTFE with DADMAC under various experimental conditions was achieved in yields up to 85%, and DADMAC percentages in the copolymers were higher than those in the feed compositions. To obtain insoluble copolymers, high CTFE feed contents (>70 mol %) were required. The other route consisting in the partial replacement of the Cl^? counter‐ions in the water‐soluble poly(DADMAC) by bistrifluoromethanesulfonimide (TFSI^?) did confer the starting material insolubility in water while maintaining its conductivity. When the fluorinated poly(DADMAC) was obtained from concentrated solutions of fluorinated surfactant, it was observed that the amount of counter‐ions exchanged was difficult to control, which limits optimization. Nevertheless, under diluted conditions, membranes with ion exchange capacity up to 0.7 meq g^?1, and conductivities close to 1 mS cm^?1 were obtained. Although their conductivities were low, these membranes fulfill the requirements for a SAFC membrane in terms of solubility in DMSO, water insolubility, and thermal stability (T_d,10% > 320 °C). When used in a fuel cell, as a binder in the membrane‐electrode assembly (MEA), significant improvements were noted (+50% of the open circuit voltage, +580% in current density, and +540% in accessible power). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2043–2058, 2009     

Strengthening Engineering Technology Innovation to Accelerate the Progress in Fuel Cleaning Course

1Introduction　Thedemandforpetroleumproductsissurgingwiththede velopmentofnationaleconomy ,whilethedomesticpetroleumprocessingcapacityexpandscontinuously .Bytheendof2 0 0 2thecrudedistillationcapacityofChinareached 2 76Mt a,rankingthefourthintheworldwhereasChinaactuallypro cessed 2 0 6Mtofcrudein 2 0 0 2withatotalproductionofgasoline,keroseneanddieselequatingto 1 2 5 6Mt,andnowChinaranksthesecondintermsofcrudeconsumptionaftersurpassingthatinJapan .AlongwithpromptimprovementofChineseeconomi…     

直喷式柴油机喷油及燃烧过程循环波动的研究

用试验与计算两种方法,研究直喷式柴油机喷油过程及燃烧过程的循环波动,指出用平均指示压力p_1来表征整个循环波动较其他方法为好.通过试验得出p_1随负荷、转速和喷油器惯量的变化情况.文中还分析了影响波动的机理,并提出了循环波动的定义,以此可算出波动率的量值.     

Determination of permeability in fibrous porous media using the lattice Boltzmann method with application to PEM fuel cells

The lattice Boltzmann method (LBM) is used to simulate the flow through an idealized proton exchange membrane fuel cell (PEMFC) porous transport layer (PTL) geometry generated using a Monte Carlo method. Using the calculated flow field, Darcy's law is applied and the permeability is calculated. This process is applied in both through‐ and in‐plane directions of the paper as both of these permeability values are important in computational fluid dynamics models of PEMFCs. It is shown that the LBM can be used to determine permeability in a random porous media by solving the flow in the microstructure of the material. The permeability in the through‐ and in‐plane directions is shown to be different and the anisotropic nature of the geometry creates anisotropic permeability. It is also found that fiber arrangement plays a large role in the permeability of the PTL. New correlations are presented for in‐ and though‐plane permeabilities of fibrous porous media with (0.6<ε<0.8). Copyright © 2008 John Wiley & Sons, Ltd.     

Effect of acidification treatment and morphological stability of sulfonated poly(arylene ether sulfone) copolymer proton‐exchange membranes for fuel‐cell use above 100 °C

Directly copolymerized wholly aromatic sulfonated poly(arylene ether sulfone) copolymers derived from 4,4′‐biphenol, 4,4′‐dichlorodiphenyl sulfone, 3,3′‐disulfonated, and 4,4′‐dichlorodiphenyl sulfone (BPSH) were evaluated as proton‐exchange membranes for elevated temperature operation (100–140 °C). Acidification of the copolymer from the sulfonated form after the nucleophilic step (condensation) copolymerization involved either immersing the solvent‐cast membrane in sulfuric acid at 30 °C for 24 h and washing with water at 30 °C for 24 h (method 1) or immersion in sulfuric acid at 100 °C for 2 h followed by similar water treatment at 100 °C for 2 h (method 2). The fully hydrated BPSH membranes treated by method 2 exhibited higher proton conductivity, greater water absorption, and less temperature dependence on proton conductivity as compared with the membranes acidified at 30 °C. In contrast, the conductivity and water absorption of a control perfluorosulfonic acid copolymer (Nafion 1135) were invariant with treatment temperature; however, the conductivity of the Nafion membranes at elevated temperature was strongly dependent on heating rate or temperature. Tapping‐mode atomic force microscope results demonstrated that all of the membranes exposed to high‐temperature conditions underwent an irreversible change of the ionic domain microstructure, the extent of which depended on the concentration of sulfonic acid sites in the BPSH system. The effect of aging membranes based on BPSH and Nafion at elevated temperature on proton conductivity is also discussed. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2816–2828, 2003     

MC68HC811E2单片机在柴油机喷油泵电控系统中的应用

介绍了以美国Ｍｏｔｏｒｏｌａ半导体公司生产的增强型８位单片机ＭＣ６８ＨＣ８１１Ｅ２为核心的柴油机喷油泵电控系统．该单片机的卓越性能以及采用电液式电控执行器使整个系统具有可靠性高，抗干扰能力强和反应速度快的特点．