UNIT HYDROGRAPHS – A COMPARATIVE STUDY1

ABSTRACT. Unit hydrographs derived by using two methods, linear programming and least squares, are compared. Test data comprise rainfall and runoff information from four storms over the North Branch Potomac River near Cumberland, Maryland. The mathematical bases of these methods for unit-hydrograph derivation are explained. The linear programming method minimizes the sum of absolute deviations, and the least squares method minimizes the sum of the squares of deviations. Computer subroutines are readily available for application of these methods. The unit hydrographs derived with the two methods are practically the same for storms 2 and 3, but differ somewhat for storms 1 and 4. However, the reconstituted direct surface runoff hydrographs are similar to those observed with the exception of the hydrograph for storm 4 which had a relatively more non-uniform rainfall excess of a considerably larger duration.     

计算机在城建档案管理中的应用

由于城市建设的不断加快,城建案卷成倍增加,传统的手工操作已不能适应档案文献增长的速度.随着现代化科学技术的发展,新的科学技术,如光盘技术、缩微技术、声像技术也在冲击着城建档案工作的领域,成为城建档案工作中不可缺少的组成部分.所有这一切,都对城建档案的管理提出了更高的要求.计算机是现代化科学技术发展的重要标志,正以它独特的高效率统占着各个领域.利用计算机管理档案是城建档案管理现代化的核心.     

电脑使用工效学评价方法的研究：键盘和鼠标使用及人体疲劳

为了进行电脑相关肌肉骨骼疾病（Computer Related Musculoskeletal Disorders）的办公室工效学研究,需要研发更有效的电脑使用工效学评价方法。鉴于键盘和鼠标是电脑操作者最主要的输入工具,而且高重复性的操作动作会增加患肌肉骨骼疾病的风险,为了保护电脑操作者的职业健康,本研究研发一套键盘和鼠标使用的工效学评价方法并且使用该评价方法评价键盘和鼠标的使用以及使用过程中的人体疲劳。评价方法设计包括：＂键盘鼠标使用统计软件＂、＂疲劳问卷系统软件＂和数据处理和结果可视化。应用此评价方法对25个对象进行了8周的纵向观察与评价。键盘鼠标使用的评价结果能够准确反映评价对象操作键盘鼠标的实际情况;对疲劳程度的分析结果也与实验室研究结论一致,得到了理论支持,成功研发了一套创新、有效的电脑键盘和鼠标使用的工效学评价方法。     

Factors influencing the willingness to pay for sustainable tourism: a case of mass tourism destinations

A 17-month research programme focused on development of an Education for Sustainability (EFS) Global Media Network at Ball State University Indiana was recently concluded. The study results include some surprising conclusions related to the contradictions between the benefits of education for global sustainability and the use of technology to facilitate that educational process in achieving a more sustainable world. This article provides an overview of the EFS Network research programme and a discussion of some of the key results and conclusions related to advantages and disadvantages of technology-based learning. The article then addresses the environmental impact of computer technology manufacturing, use, and after-use. Research findings are utilized to illustrate the ecological footprint of computer-based education. The article concludes with a discussion about achieving a balance between the need for global-to-local sustainable education and the environmental impact of technology use for sustainable education.     

A SURVEY OF HYDROLOGY COURSE CONTENT IN NORTH AMERICAN UNIVERSITIES1

ABSTRACT: This report presents the results of a survey of hydrology faculties of colleges and universities in the United States and Canada. Information is presented on topics covered in classes, allocation of class periods to individual topics, textbooks, prerequisites, computer use, and accreditation categories for hydrology courses offered by engineering departments. Hydrology courses generally require courses in fluid mechanics, mathematics, statistics, and computer science as prerequisites. Topics that receive the largest allocation of time in both introductory and advanced courses include rainfall-runoff relations, the hydrologic cycle, routing and open channel flow, and statistics. Advanced courses place greater emphasis on watershed models than do the introductory courses. Hydrology courses at both levels allocate the smallest amounts of time to snow hydrology ground-water hydrology, and “other topics.” Very few courses include field or experimental work. In a discipline where computer modeling is a major tool, this lack of field and data-collection experience may lead students to underestimate the uncertainties associated with data used to calibrate models and the modeling results themselves. Survey responses on hydrology courses taught in departments other than civil engineering were too few to permit detailed analysis. Most of these courses spend approximately two-thirds of available class time on the same topics as presented in engineering hydrology courses. The balance of class time is spent on topics that emphasize the specialized interest of the particular discipline, such as soil physics and soil moisture in agricultural engineering.     

浸出时间、H2SO和Fe^3＋浓度对硫脲浸金的影响

目前废旧电脑的产生量日益增加,废旧电脑主板中含有丰富的可回收金属资源,对其回收处理意义重大。本实验采用硫脲对电脑主板中的金进行浸取研究,在硫脲浸金过程中,主要通过调整时间、硫酸浓度、Fe^3＋浓度,考察对浸金的影响。研究结果表明：当t=60min、硫酸浓度为15％、Fe^3＋浓度为0.45％时,金的浸出最大,可达91.14％。因硫脲具有浸金速率快,试剂易再生,对环境污染小、反应条件易控制等优点适于应用于实际生产。     

SUITABILITY OF SOME FRESH WATER AND MARINE FISHES FOR USE WITH A MINICOMPUTER INTERFACED BIOLOGICAL MONITORING SYSTEM1

ABSTRACT: Electronic modifications necessary to adapt an existing fish opercular movement monitor for use in salt water are described. Ten species of fresh and salt water fishes were tested for suitability as test organisms for future studies of pollutional effects. It was concluded that with proper tank design most species would provide useful data and that the system could be easily adapted for use in marine situations.     

Estimation of waste from computers and mobile phones in Iran

The amount of waste electrical and electronic equipment (WEEE) has been rapidly growing in recent years. Estimation close to reality of the future amounts of WEEE as a function of time is critical to effective their management. Wastes from mobile phones and computers are one of the several subgroups of WEEE. The objective of this study was to estimate past and future trends in the generation of obsolete computers and mobile phones in Iran. For this purpose a combination of two models were used. At the beginning, time-series multiple lifespan model was used to estimate outflows end-of-life obsolete equipment. Then, using the simplified logistic function model by Excel software, the values of obsolete computers and mobile phones in the future were estimated. The study found that the amount of E-waste generation in the country was 20 million wasted computers until 2016 and 39 million wasted mobile phones until 2014. Results of the time series model analysis showed a total amount of 2.8 million waste computers would be reused by 2016 and 4.2 million mobile phones would be reused by 2014. The results of the logistic equation indicate that by the year 2040 there will be 50 million units of obsolete computers. According to the same model 90 million mobile phones will be obsolete by 2035. Increase in the number of computers and mobile phones was fitted into the logistic model and the results showed that the saturation level of generation of obsolete computers and mobile phones are 24 and 21 years respectively following the base year 2016 and 2014.     

High technology firms and planning policy: a case study of research machines limited,Oxford

This article reviews planning issues relating to “high‐tech” industry in Britain, and uses a case study of a manufacturer of micro‐computers in Oxford, England as a focus for a discussion. It concludes that town planning categories are not, in themselves, a constraint on high technology firms, and suggests that the provision of sites and premises by local authorities is a useful and undervalued task.     

A WATER QUALITY MODEL FOR A CONJUNCTIVE SURFACE-GROUNDWATER SYSTEM: AN OVERVIEW1

ABSTRACT. A mathematical model to predict water quality in a surface-groundwater system is under development. This project is being sponsored by the Environmental Protection Agency. The ultimate goal of this study is to obtain cause and effect relationships between pollutant sources and the ensuing concentrations at different locations in a basin. Several programs are used to model the various hydrologic processes occurring in nature, namely: rainfall, runoff, flow in surface bodies of water, infiltration, and groundwater flow. At every time step in the simulation, the water quantity computations for the above hydrologic models are performed first. Subsequently, the results of these computations, typically in the form of flow velocities, are used as input to the water quality calculations. The water quality routines involve the modeling of the associated physical, chemical, and biological processes. In this study, emphasis is being placed on pollution in agricultural areas. Accordingly the Lake Apopka basin in Central Florida is being used as the application site.