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41.
天然含水量ω是土的最基本物理量指标之一。采用数理统计方法,建立经验方程来修正土的天然含水量ω的测定值,使修正后的天然含水量数值与实际中的真值符合程度更为接近,效果甚好。 相似文献
42.
Simulation of water and nitrogen dynamics in soils during wastewater applications by using a finite-element model 总被引:4,自引:0,他引:4
Vassilis Z. Antonopoulos 《Water Resources Management》1993,7(3):237-251
A mathematical model was developed to simulate water movement, mass transport, and nitrogen transformations in soils during wastewater applications. The model is one-dimensional and based on the Galerkin finite-element method. The submodel of mass transport of nitrogen incorporates the convection-dispersion processes of ammonium and nitrate nitrogen, nitrification, denitrification, ammonium exchange and uptake of ammonium and nitrate ions. The accuracy and validity of the proposed model was examined by comparison with an explicit-implicit finite-difference model results. The model was used for simulation of water and nitrogen dynamics during wastewater application in homogeneous and multi-layered soils under different N concentration, rate, duration and scheduling of application. 相似文献
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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. 相似文献
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No authorship indicated 《Canadian Metallurgical Quarterly》2004,59(8):787
Provides the biography of Cortney S. Warren and announces that she has received the APA Psi Chi/APA Edwin B. Newman Graduate Research Award (2004) for an outstanding research paper whose findings examine the potential for ethnicity to protect against body image disturbance by moderating the relationships between awareness and internalization of a thin physical ideal and body dissatisfaction. A selected bibliography is also provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
47.
刚性圆板自由落体在水面上的冲击压力 总被引:2,自引:0,他引:2
本文对一个刚性圆板自由落体在水面上的冲击过程建立了比较精确的理论模型,并建立了相应的数值格式。计算结果与已有的实验结果符合良好,通过计算进一步给出了下落质量和下落高度对冲击压力峰值的影响。 相似文献
48.
脱离子水处理单元是一种顺序控制单元,对时序控制有严格的要求。文中介绍了一种新型的控制系统NETWORK6000在PTA装置脱离子水单元中的应用状况,为中小规模的装置应用提供了一种较典型的思路和借鉴,最后对系统的应用状况进行了评价。 相似文献
49.
Takaaki Wajima Tomoe Shimizu Yasuyuki Ikegami 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(6):921-927
BACKGROUND: This study aimed to investigate the synthesis of zeolites from paper sludge ash (PSA) with added diatomite to remove both NH4+ and PO43? 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 PO43?. 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 PO43? by precipitation, which is preferable for water purification applications. Copyright © 2008 Society of Chemical Industry 相似文献
50.