Assessment of the energy and exergy utilization efficiencies in the Turkish agricultural sector

This study deals with evaluating the energy and exergy utilization efficiencies in the Turkish agricultural sector over a 12‐year period from 1990 to 2001. In the energy and exergy analyses, two main energy sources, namely fuels and electricity, are taken into consideration, while the sectoral energy and exergy efficiencies are compared for this period. These main energy sources include diesel for tractors and other vehicles, and electricity for pumps. Overall energy utilization efficiencies are obtained to vary between 29.1 and 41.1%, while overall exergy utilization efficiencies are found to range from 27.9 to 37.4% in the analysed years, respectively. It may be concluded that the present technique proposed here may be used as a useful tool in analysing and evaluating the energy and exergy utilization efficiencies, identifying energy efficiency and/or energy conservation opportunities and dictating the energy strategies of countries. Copyright © 2005 John Wiley & Sons, Ltd.     

刚性圆板自由落体在水面上的冲击压力

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。     

回顾与展望──庆祝建院40周年

介绍了我院资源开发工程系的历史、现状和前景，指出了面临的问题及摆脱困境的途径。     

关于加强国土资源管理的思考

全文围绕树立和落实科学发展观这一主题 ,研究和探索如何在新时期、新阶段进一步做好国土资源管理工作的新思路、新途径和新方法。提出要进一步加强国土资源宏观管理 ,更好地为甘肃省经济社会的协调、可持续发展提供保障服务。     

NETWORK6000在脱离子水处理过程中的应用

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。     

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     

轧后穿水冷却工艺对棒材组织性能的影响

针对轧机产量提高后冷床冷却能力不足的问题 ,研制开发了棒材轧后穿水冷却技术。通过对小规格 2 0MnSiV热轧带肋钢筋进行轧后穿水冷却 ,钢材上冷床温度降低了 90～ 110℃ ,提高了产品质量 ,改善了各项力学性能 ,抗拉强度平均提高了 3 5～ 40MPa ,钢材性能合格率由 97.5 %提高到了 99.6% ,解决了冷床冷却能力不足、制约生产的瓶颈问题。     

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。     

Gender differences in computerised and conventional educational tests

Abstract Research has demonstrated girls to outperform boys on conventional literacy tests. The present studies concern gender differences on computerised educational tests. Seventy-one children were tested using LASS Secondary and a set of seven conventional measures. No significant gender differences were found on any of the LASS Secondary modules, although females did outperform males on a conventional spelling test. A further 126 pupils were tested on computerised and paper versions of the LASS Secondary reading, spelling and reasoning modules. No gender differences were found on the computerised versions, but there were significant differences on the paper versions of the reading and spelling modules favouring females. In a third study, 45 children were administered computerised and paper versions of the LASS Junior reading and spelling modules. There were no significant differences on the computerised modules, but girls performed significantly higher than boys on the paper version of the spelling module. It is possible that computerised assessment does not detect the established gender effect due to differences between males and females in motivation, computer experience and competitiveness. Further large-scale studies are necessary to confirm these findings.