Effect of water inlet velocity on thermal stratification in a mantled hot water storage tank

Thermal stratification in a mantled hot water storage tank is analysed numerically for different water inlet velocities. The aim is to obtain higher thermal stratification and supply hot water for usage as long as possible. Twelve different water inlet velocities to the hot water storage tank are considered. The numerical method is validated by comparing its results against experimental and numerical results from the literature. It turned out that the results obtained from the numerical analysis have shown very good agreements with the results from previous works. As a result, the water temperature in the tank increases with the increase of the water inlet velocities to the mantle but this increment is not proportional. After a period of operation of 7.2 h, which corresponds to the average sunshine duration in Turkey, temperature increments of 6.5 and 35 K have been estimated for the hot water inlet velocities of 0.01 and 0.3 m s^?1, respectively, at a radial distance of 0.1 m and a height of 1 m inside the storage tank. Copyright © 2005 John Wiley & Sons, Ltd.     

Biodesulphurization of Hungarian lignite and sub-bituminous coal

The annual SO₂ emission is approx. 0.6 million tons in Hungary because of the high amount of sulphur in the power plant coals. Since Hungary has signed the European Environmental Agreement, the high sulphur emission has to be gradually reduced. To overcome the acid rain problem, the biodesulphurization of Hungarian power plant coals has also been started in Hungary. The R&D programe of biodesulphurization has been launched in 1990. According to our findings the biodesulphurization process is a suitable tool for reducing the pyritic sulphur content in lignite and sub-bituminous coal.     

坑道用水下堵漏剂的研制

坑道水下堵漏剂的研制包括F－1、F－2和F－3型。其中F－1是一种有机堵漏剂，它可以在水中固化；F－2是一种无机防水堵漏剂，施工方便；F－3是速凝型，它可在瞬间固化，能对坑道的涌水口进行堵漏。     

煤炭企业管理的激励方式及运用

本文介绍了煤炭企业管理的激励方式以及激励机制的具体运用。     

马鞍山煤矿瓦斯地质理论在防突工作中的应用

总结了实际工作中防突管理的经验和问题 ,探讨了科学理论与具体实际的有机结合与统一 ,采取针对性强的有效措施 ,确保突出矿井的安全生产     

煤矸石作水泥混合材的活化方法研究

论述了煤矸石用作水泥混合材时如何激发其活性的若干方法 ,介绍了通常所用的热激活、物理激活和化学激活煤矸石的机理。实验显示了各种激活方法的效果 ,近而讨论了提高煤矸石活性时应注意的问题     

Zeolite synthesis from paper sludge ash with addition of diatomite

BACKGROUND: This study aimed to investigate the synthesis of zeolites from paper sludge ash (PSA) with added diatomite to remove both NH₄⁺ and PO₄^3? for water purification. The PSA had low Si and significant Ca contents. Four types of diatomite: white (T‐W) and brown (T‐B) from deposits of marine origin in Takanosu, and white (S‐W) and gray (S‐G) from lacustrine deposits in Shonai, were added to NaOH solution to increase the Si content and thereby synthesize zeolites with high cation exchange capacity (CEC). RESULTS: The order of the amounts of Si extracted from the diatomite to the alkali solution was S‐W > T‐W = T‐B > S‐G, which correlates with the amorphous SiO₂ content of diatomite. The original ash without addition of diatomite yielded hydroxysodalite with CEC of about 1.0 mmol g^?1. For all samples, the addition of diatomite to the solution yielded zeolite‐P with a higher CEC, but the addition of excess Si inhibited the synthesis of zeolite‐P, and the CEC of the product was low. A product with high CEC including zeolite‐P was obtained in a solution with around 500 mmol L^?1 of Si concentration, and had the ability to remove both NH₄⁺ and PO₄^3?. CONCLUSION: Diatomite has the potential for used as an additive for the synthesis of high CEC zeolite from PSA. The product with zeolite‐P exhibited relatively high CEC, capacity for NH₄⁺ uptake, and the ability to remove PO₄^3? by precipitation, which is preferable for water purification applications. Copyright © 2008 Society of Chemical Industry     

GPS在水面流速流向测量中的应用

传统的水面流速流向测量多采用经纬仪交会法,此法需要大量的人力和设备,工作量大且费时。近几年,随着全球定位系统(GPS)的广泛应用和实践,在一定范围内,采用GPS定位法替代经纬仪交会法施测水面流速流向。介绍了GPS定位法的测量原理、设备,以及测量方法。通过对GPS定位法的精度和优缺点的分析,得出采用GPS定位法施测水面流速流向具有较高的推广价值。     

水上地震折射互换法误差分析

在理论上，用源检互换的方法进行折射地震勘探是没有误差的，在某些特殊条件下无法铺设检波器而又必须进行折射地震勘探时它也是唯一的选择，然而，在实际工作中，由于各种因素的影响，其误差是不可忽略的。为此，本文从地震折射运动学的角度对水上地震折射互换法因过河钢丝绳的重量、水的流速和流向、炮点深度等客观因素造成的解释误差进行了分析，揭示了水上地震折射互换法应注意的问题。这对水上地震折射互换法的资料解释进行误差校正提供了理论基础。     

Effect of olive residue benzylation on the thermal and mechanical properties of poly(vinyl chloride)/olive residue composites

The changes in mechanical properties, the thermal stability, and the water absorption capacity of poly (vinyl chloride)/olive residue flour composites were studied as a function of various residue olive flour ratios, i.e., 0, 5, 15, and 25% by weight taking into account the effect of benzylation chemical treatment of the filler. The study showed that composite samples prepared with the untreated filler exhibited higher tensile modulus and hardness compared with the neat resin, whereas elongation and tensile strength were observed to decline. On the other hand, the PVC hardness was found to increase with addition of the untreated olive residue flour (ORF), however the composite samples prepared with the benzylated flour exhibited lower hardness than those prepared with untreated olive residue. Moreover, the amount of absorbed water depends on the amount of filler in the composite. The comparison of the results obtained from the samples of F5, F20, and F30 formulations between the untreated and treated ORF indicated a reduction in absorbed water for the composite samples containing treated ORF with benzyl chloride. As a result, the mechanical properties of the treated composites were improved. Furthermore, the thermal characterization of the different samples carried out by color change test and thermogravimetric analysis revealed an increase in the onset temperatures of decomposition for the treated composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008