An Experimental Investigation of a new Method for Protecting Bends from Erosion in Gas—Particle Flows

Bend erosion is a fairly serious problem in conveyer pipe system. This paper intends to introduce a new anti-erosion method for bend: ribbed anti-erosion method. Experimental research has been done by fixing ribs in the range of 10° – 70° on the outer-wall of inside 90°-bend. As a result, the experiment got anti-erosion efficiency: 93.02%. It shows that ribbed bend technology is a simple and efficient anti-erosion method. Besides, the experiments indicate that rectangle ribs tend to do more obvious anti-erosion effect than square ribs do when they have equal height.     

The Robust Optimization for Large-Scale Space Structures Subjected to Thermal Loadings

Large-scale space structures may experience unexpected thermal-elastic deformation due to thermal loadings in space. This thermal response could be minimized by using optimization method in design phase and the uncertainty of material properties should also be considered to ensure the reliable performance of the produced structure. For this purpose, the robust optimization is applied to this kind of structures in this paper. Firstly, a perturbation based stochastic finite element program is developed, which is tailored for the problem of thermal-elastic deformation of thin-walled structures subjected to incident thermal flux and energy emission through radiation. Based on this program, a robust design scheme is formulated as a two-objective optimization problem, in which all required sensitivities are calculated analytically. Then, the Pareto front of this problem is effectively determined by using the adaptive weighted sum method. Finally, numerical examples are presented to illustrate the validity and capability of this proposed method.     

Influence of the structural and surface characteristics of activated carbon on the catalytic decomposition of hydrogen iodide in the sulfur–iodine cycle for hydrogen production

Coal-based activated carbon (AC-COAL) catalysts subjected to acid treatment were tested to evaluate their performance on hydrogen-iodide (HI) decomposition for hydrogen production in sulfur-iodine (SI or IS) cycle. The effects of acid treatment on catalysts and the relations between sample properties and catalytic activities were discussed. The AC-COAL obtained by non-oxidative acid treatments had the best catalytic activity. However, the catalytic activity of AC-COAL decreased after the treatment of nitric acid. Higher surface area, higher carbon contents, lower ash contents and fewer surface oxidation groups contributed to the catalytic activity of ACs. HI decomposition on the AC surface itself may be due to high densities of unpaired electrons associated with structural defects and edge plane sites with similar structural ordering. Moreover, the oxygen-containing groups reduced the electron transfer capability associated with the basal plane sites.     

双底物双菌种固定化生产乙醇串联发酵的新工艺

酿酒酵母和毕赤酵母经海藻酸钙固定化后分别装入两个串联的固定床内，以保证酿酒酵母代谢葡萄糖的高效及毕赤酵母代谢木糖所需要的供氧。通过对稀释率、初糖浓度及通气量等操作参数进行的实验研究，证明这是一种能实现混合糖连续发酵生产酒精的新工艺。     

造纸污泥流化床燃烧特性及燃烧过程数学模型

对造纸污泥在流化床中燃烧时的失重、粒径和密度变化、水分蒸发和挥发分的析出等过程进行了试验研究,提出了一种适用于高水分的多孔介质污泥并综合考虑传热传质过程的水分蒸发和挥发分析出数学模型,通过求解能量方程和组分守恒方程,用数学方法描述并预测了造纸污泥在流化床内的水分蒸发和挥发分析出过程,并将理论结果与试验结果进行对比,二者吻合较好。     

风险评估在丰满水电站大坝的应用研究

大坝安全管理本质上是一个风险管理、风险决策的过程，近十几年来，风险评估技术在西方发达国家的大坝安全管理中得到了快速的发展和应用。本文根据风险评估的理论和方法，对影响丰满大坝安全的主要初始事件进行了风险分析，对大的失事风险进行了探索研究，并据此对丰满大坝的补强加固提出了初步建议，可供实际工作或类似工程参考。     

Mixed $${L}_{1}$$ norm and $${L}_{2}$$L2 norm regularized sparsity adaptive matching pursuit algorithm

The sparsity adaptive matching pursuit (SAMP) algorithm has an advantage of reconstructing signals without the prior information of the sparsity level. However, the required computational power is high and the reconstruction performance is not satisfied for perturbed systems. This is because this algorithm is based on the expectation maximization algorithm. Also, a pseudo-inverse operation of the matrix is employed to select the element candidates of the sensing matrix in each iteration. In this paper, a mixed \(L_{1}\) norm and \(L_{2}\) norm regularized algorithm is proposed to address these issues. Similar to the SAMP algorithm, the regularized algorithm also reconstructs the signals without the prior information of the sparsity level. Different from the SAMP algorithm, the element candidates of the sensing matrix are selected by the \(L_{2}\) norm strategy in each iteration. Experiments are performed on an ideal simulation system, a perturbed simulation system and real image reconstruction. Simulation and real image reconstruction experimental results indicate that the regularized algorithm has lower computational power than the SAMP algorithm. Also, the proposed algorithm has better reconstruction performance on the perturbed system compared to the SAMP algorithm.     

Hydrogen production from water hyacinth through dark- and photo- fermentation

This article discusses the method of producing hydrogen from water hyacinth. Water hyacinth was pretreated with microwave heating and alkali to enhance the enzymatic hydrolysis and hydrogen production in a two-step process of dark- and photo- fermentation. Water hyacinth with various concentrations of 10–40 g/l was pretreated with four methods: (1) steam heating; (2) steam heating and microwave heating/alkali pretreatment; (3) steam heating and enzymatic hydrolysis; (4) steam heating, microwave heating/alkali pretreatment and enzymatic hydrolysis. Water hyacinth (20 g/l) pretreated with method 4 gave the maximum reducing sugar yield of 30.57 g/100 g TVS, which was 45.6% of the theoretical reducing sugar yield (67.0 g/100 g TVS). The pretreated water hyacinth was used to produce hydrogen by mixed H₂-producing bacteria in dark fermentation. The maximum hydrogen yield of 76.7 ml H₂/g TVS was obtained at 20 g/l of water hyacinth. The residual solutions from dark fermentation (mainly acetate and butyrate) were used to further produce hydrogen by immobilized Rhodopseudomonas palustris in photo fermentation. The maximum hydrogen yield of 522.6 ml H₂/g TVS was obtained at 10 g/l of water hyacinth. Through a combined process of dark- and photo- fermentation, the maximum hydrogen yield from water hyacinth was dramatically enhanced from 76.7 to 596.1 ml H₂/g TVS, which was 59.6% of the theoretical hydrogen yield.     

Partial oxidation of methane in a reciprocal flow porous burner with an external heat source

A reciprocal flow porous burner with an external heat source in the middle section was studied numerically to access the reactor efficiency for synthesis gas generation. The temperature and species profiles were predicted using a two temperature model with a detailed chemical mechanism. The effect of the variation of the power of the external heat source on the hydrogen and carbon monoxide yields was studied. The energy conversion efficiencies of the system with various power levels of the external heat source were evaluated. It is found that H₂ and CO yields increase significantly with the addition of the external heat source due to the temperature increase in the middle section of the burner. The CO₂ emissions remain small. The methane conversion ratio increases with increase of the power of the external heat source reaching 97%. The H₂ and CO conversion ratios yields are nearly doubled as the power of the external heat source increases from 0 to 750 W. The cold gas energy conversion efficiency decreases as the power of the external heat source increases. At the same time, the syngas energy conversion efficiency increases from 41% to 70%, while hydrogen energy conversion efficiency increases from 28% to 46%.     

IEC 60870-5-101的应用与实践

IEC 60870-5-101协议在实践普及过程中,由于用户和制造厂家的理解和使用方式上的不同,效果也不同。文中就通信效率、实时性、数据传输的可靠性等问题进行了分析,并介绍了华东电网的应用经验。