甲烷/空气混合气燃爆特性的实验研究

对不同初始压力和温度条件下的甲烷/空气混合气的爆炸极限进行实验研究,利用最大-最小准则来确定爆炸极限.分析了温度和压力对甲烷/空气混合气燃爆特性的影响.采用氮气作为惰性气体,对其防爆抑爆效果进行了实验研究.     

开发秋季气候资源,发展再生稻生产

南充地区秋季气候资源丰富,近几年由于推广良种良法,再生稻由零星试种到区域性种植获得成功,预示着新耕作制度的出现,这是开发秋季气候资源的一项重大突破。本文以大量数据阐述发展再生稻的生产潜力,分析了再生稻的生态气候适应性,指出伏旱高温和秋季低温冷害是发展再生稻的两个不利气象条件,并将全区划分为适宜、比较适宜和不适宜3个区,提出了相应的技术措施,为趋利避害发展再生稻提供了气象科学依据。     

THE APPLICABILITY OF MORTON'S AND PENMAN'S EVAPOTRANSPIRATION ESTIMATES IN RAINFALL-RUNOFF MODELING1

ABSTRACT: Estimates of the upper constraint on actual evapotranspiration are required as input data in the majority of rainfall-runoff models. This paper compares and discusses the applicability of Penman's potential evapotranspiration estimates and Morton's wet environment evapotranspiration estimates in rainfall-runoff modeling applications. Morton's wet environment evapotranspiration depends only on the atmospheric variables and is the estimate of evapotranspiration that would occur when water supply is not limiting. It is a conceptually more correct representation of the upper constraint on actual evapotranspiration compared to Penman's potential evapotranspiration which is dependent on the water supply to the soil-plant surfaces. Although Penman's potential evapotranspiration and Morton's wet environment evapotranspiration are two different quantities, comparison of the two estimates using data from different climatic regions throughout Australia indicate that they provide similar magnitudes of the upper limit of actual evapotranspiration at moderate climatic conditions when reliable estimates are required in rainfall-runoff models. The two estimates can therefore be used interchangeably in rainfall-runoff modeling applications.     

Forest product use at an upper elevation village in Nepal

This paper describes forest product use at Chimkhola, an upper elevation village of west central Nepal. Villagers have large herds of livestock that they use to fertilize agricultural fields by holding the animals on cropland for one to several weeks prior to planting. Herds are moved sequentially from one group of fields to another until all are planted, and then families take animals into the forests. Herders, therefore, live in temporary shelters away from the homestead throughout the year, and for much of the year feed their livestock fodder cut from forest trees. By combining repeated interviews of sample households, one-time interviews with a large sample of village families, and direct measurements of forest products being used, I found that livestock maintenance consumes 74% of the hand-harvested wild biomass: 26.4% for green fodder, 32.3% for fuelwood at the herder's hut, and 13.8% for construction of the herder's hut. Fuelwood burned at the homestead is the next largest consumer, 17.6%. Villagers also use small amounts of forest materials for house construction, charcoal, agricultural implements, and bamboo for baskets and mats. The large amounts used by herders and livestock at Chimkhola mean that wild vegetation use there far exceeds the measurements made by previous reliable studies at other communities. This system of forest use is, however, degrading Chimkhola's forests and gradually converting them to shrublands.     

ECONOMIC ANALYSIS OF WATER-SAVING TECHNIQUES IN IRAN1

ABSTRACT: The possibility of increasing the water supply for irrigation through adoption of more efficient water-application techniques as an alternative to new irrigation projects was studied in an irrigated region of Iran. Excessive water application at the farm level ranks high among the causes of water shortages in the selected region. An empirical analysis of the effect of water-saving technology on the farm operator's net return was made choosing two farms in the region as a case study. The problems facing these farms are common to most farms throughout the country. The results of the budgeting analysis of the selected farms indicated that an improvement in irrigation technique can result in the expansion of water supply and higher marginal value product for water. Comparing the costs of irrigation systems with the net returns resulting from the higher efficiency showed that such an investment is economically feasible.     

PROFITS,JOINT COSTS AND WATER QUALITY CONTROL1

ABSTRACT. Federal guidelines for the establishment of water quality standards prohibit degradation of the properties of all or part of the nation's aquatic resources. It is probably correct that streams, lakes and aquifers should be free of toxic substances while non-poisonous deposits should be abated. However, an extreme opposing position is held by some proponents of pollution who intend to continue discharging waste materials until forced to stop. Although it would seem otherwise, the underlying problem is that polluters' points of altercation possess merit in particular instances. Accordingly, efficient abatement will require that appropriate laws be formulated in such a manner that the nature of economic reasons for the disposal of waste materials be disclosed. Moreover, the technological ability to create byproducts from these particular elements or compounds can advance only over time. This, coupled with the fact that scientists have not developed inexpensive treatment methods which are totally effective, justifies more flexible formal regulations. Excessive rigidity of standards could impose a burden on polluters that is greater than the cost to society which the damaging firm or individual is generating. On the other hand, uniform rules in some cases could be considered so lenient as to allow flagrant contamination which unduly injures downstream users.     

输油管道对环境的影响及其环境保护措施

使用管道长距离输送原油和成品油（管输）是石油工业一种现代文明的生产手段，它具有密闭、效率高、成本低和安全可靠等优点，在油品输送方面占据着主导地位。我国应用长距离输油管线始于５０年代末期，在七、八十年代有了较快的发展。在管道建设的施工期会对地表造成破坏，管输油品的首站、中间泵站、末站及沿途管线由于腐蚀、事故等产生漏失油品而造成环境污染。本文介绍了几种漏失检测方法。     

南昌市名特优农产品生产基地布局规划

本文通过对南昌市名特优农产品资源、生产现状和市场条件的综合分析，确立了发挥地区资源优势，重点发展的名特优农产品，并进行了科学合理的规划和布局。     

把污染预防纳入化工过程和产品的研究开发与设计中

介绍了污染预防的概念以及在化工过程和产品的研究开发和设计中考虑污染预防的基本方法。并给出了一些简单实例予以说明。     

Measures of speeding from a GPS-based travel behavior survey

Objective: Lacking information about actual driving speed on most roads in the Minneapolis–St. Paul region, we determine car speeds using observations from a Global Positioning System (GPS)-based travel survey. Speed of travel determines the likelihood and consequences of collisions. We identify the road segments where speeding occurs. This article then analyzes the relationship between link length, traveler characteristics, and speeding using GPS data collected from 152 individuals over a 7-day period as part of the Minneapolis–St. Paul Travel Behavior Inventory.

Methods: To investigate the relationship, we employed an algorithm and process to accurately match the GPS data with geographic information system (GIS) databases. Comparing actual travel speed from GPS data with posted speed limits, we measure where and when speeding occurs and by whom. We posit that link length and demographics shape the decision to speed.

Results: Speeding is widespread under both high speed limits (e.g., 60?mph [97?km/h]) and low speed limits (less than 25?mph [40?km/h]); in contrast, speeding is less common at 30–35?mph (48–56?km/h). The results suggest that driving patterns depend on the road type. We also find that when there are many intersections, the average link speed (and speeding) drops. Long links are conducive to speeding. Younger drivers and more educated drivers also speed more, and speeding occurs more often in the evening.

Conclusions: Road design and link length (or its converse, frequency of intersections) affect the likelihood of speeding. Use of increasingly available GPS data allows more systematic empirical analysis of designs and topologies that are conducive to road safety.