Comparative Analysis of Synthetic Natural Gas versus Hydrogen Production from Bagasse

A rigorous and comparative evaluation of two biomass‐to‐gases (BtG) conversion routes was performed and, according to this outcome, it is suggested which of the options evaluated is most desirable. These options, the hydrogen and synthetic natural gas (SNG) production, were designed in Aspen Plus process simulation software. Sugar cane bagasse was considered as feedstock. Mass and energy balance data were extracted from the simulations, and consequently thermodynamic (exergy analysis), economic (financial and uncertainty analysis), and environmental (CO₂ emissions) evaluations were carried out. Exergy and environmental analysis favor the SNG production while the hydrogen route provides higher profits.     

Control of the gas medium in diffusion welding

Methods of controlling the gas medium in diffusion welding are investigated. A method of control using film gas analysers is proposed. The method increases the accuracy, and can be used to detect the distribution of the composition of the gas medium in the cross section of the contact gap and determine the oxygen concentration in small gaps between the welded components.     

The combustion behavior of epoxy-based multifunctional electrolytes

Multifunctional or structural electrolytes are characterized by ionic conductivity high enough to be used in the electrochemical devices and mechanical performance suitable for the structural applications. Preliminary insights are provided into the combustion behavior of structural bi-continuous electrolytes based on bisphenol A diglycidyl ether (DGEBA), synthesized using the techniques of reaction induced phase separation and emulsion templating. The effect of the composition of the structural electrolytes and external heat flux on the behavior of the formulations were studied using a cone calorimeter with gases formed during testing analyzed using FTIR. The composition of the formulations investigated was changed by varying the type and amount of the ion conductive part of the bi-continuous electrolyte. Two ionic liquids, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIM-TFSI) and 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF₄), as well as a deep eutectic solvent (DES) based on ethylene glycol and choline chloride, were used. The results obtained confirm that time to ignition, heat release rate (HRR), total mass loss, as well as the composition of the gases released during tests depend on the composition of the formulations. Addition of liquid electrolyte is found to reduce the time to ignition by up to 10% and the burning time by between 28% and 60% with the added benefit of reducing the HRR by at least 34%. Gaseous products such as CO₂, CO, H₂O, CH₄, C₂H₂, N₂O, NO, and HCN were detected for all formulations with the gases SO₂, NH₃, HCl, C₂H₄, and NH₃ found to be for certain formulations only.     

Computational Fluid Dynamics (CFD) Modeling of Gaseous Pollutants Dispersion in Low Wind Speed Condition: Isfahan Refinery,a Case Study

A 3D computational fluid dynamics (CFD) model is developed to predict the dispersion of gaseous pollutants released from different stacks in Isfahan refinery in Iran. Three types of turbulent models including the standard k–?, the RNG k–?, and the realizable k–? models are compared and considered. The results of model are compared with the experimental data obtained by measuring the CO₂ concentration inside and close to the refinery boundaries. The comparison shows the sufficient precision of model predictions. By using the design of experiment (DOE) technique, the effects of model parameters are investigated on the results. The results of standard k–? model for Sc _t = 0.5 and h_r = 2 m, the realizable k–? model for h_r = 2 m, and the RNG.k–? model for h_r = 2.5 m provide more acceptable results when these results are compared with the models responses with ideal values of these parameters. The latter gives some better results for the case of Isfahan refinery.     

气体放电动力学方程组的数值方法

气体放电动力学方程组是一组时变、非线性的偏微分方程组,求得其数值解决非易事。本文给出了用伽略金有限元法求解这组方程的主要步骤,计算结果证明了这种方法是有效的,可信的。本文是用大型高速计算机分析气体放电过程的尝试,所得结果与实验结果十分接近(计算结果另文发表),证明将计算方法用于气体放电研究是很有前景的。     

Finite-Volume-Particle Methods for Models of Transport of Pollutant in Shallow Water

We present a new hybrid numerical method for computing the transport of a passive pollutant by a flow. The flow is modeled by the Saint-Venant system of shallow water equations and the pollutant propagation is described by a transport equation. The idea behind the new finite-volume-particle (FVP) method is to use different schemes for the flow and the pollution computations: the shallow water equations are numerically integrated using a finite-volume scheme, while the transport equation is solved by a particle method. This way the specific advantages of each scheme are utilized at the right place. This results in a significantly enhanced resolution of the computed solution     

洗浴废水回用处理的水质控制研究

采用混凝-沉淀-过滤-消毒处理工艺处理洗浴排水，在水温10℃时，主要控制指标浊度、COD、BOD5和ABS平均平除率分别为98.1%，95.2%，93.3%和68.2%，出水水质完全满足中水控制指标要求，试验中发现出水浊度与COD和BOD5有着很好的相关性，可以出水浊度监测COD和BOD5指标，使运行管理简便、结果完全可靠。     

高斯扩散模式平均风速_u~－取值的合理性研究

高斯扩散模式在实际应用中平均风速的取值混乱，本文从理论上阐明的合理取值应为有效源高Ｈｅ处的平均风速（），并指出了采用地面风速或烟囱出口高度处平均风速（）计算污染物地面浓度的误差范围。     

岩石集中装药爆炸能量分布的计算

本文分析了岩石集中装药爆炸破坏过程,计算了爆破过程所消耗的各种能量的分布。计算结果表明,岩石中2~#岩石硝铵集中药包爆炸所消耗的爆炸气体膨胀能量、冲击波能量分别占装药总能量的50％～60％和10％～20％,无用能约占20％～30％。     

加强空调风管清洗维护的必要性

阐述了空调风管清洗维护的必要性，介绍了风管尘埃污染物的分布情况与危害性，论述了风管清扫的方法与技巧，以提高空调效率，节约能源，提高人民的生活水平。