稠油火驱开采技术节能减排效果分析

火驱作为稠油热采的有效接替技术,与注蒸汽开采技术相比,具有采收率高,能耗低,CO_2排放少的优势。文章从火驱驱油机理特征阐述了火驱与注蒸汽技术的不同点,从燃料开采能耗、热效率、注入剂资源、数据对比四个方面分析火驱比注蒸汽热效率高,无燃料开采成本,能耗是注蒸汽的50%;从CO_2气体排放方式和排放量对比可知,火驱能够减少温室气体排放,为油田节能减排、环保生产起到积极作用。     

转基因植物及其对生态坏境的影响

转基因植物的大量释放在给人类带来希望和益处的同时,也会对生态环境造成一定的影响。文章就国内外近年来关于转基因植物对植物、动物、病毒、尘物多样性以及土壤微生物等方面影响的研究作一评述。     

火驱尾气排放系统研究及应用

针对火驱开发过程中尾气存在的安全隐患及对油井产量的影响,对现有的工艺流程进行优化,实现气液分输、安全外排,保证集输系统的安全性,同时建立安全防控体系、定时监测,消除安全隐患;并对现有的尾气处理工艺进行改造,将传统的脱硫罐串联改为并联,增大了处理能力。同时增加管径尺寸,降低了收气阻力,提高了尾气处理速度,最终提高单井产量。解决了火驱开发过程中的瓶颈难题,为火驱项目的规模化应用提供了保障。     

因素食而诞生的动物伦理学名著

彼得·辛格和汤姆·雷根都是素食者,他们从关注素食问题开始,走上了动物伦理学的研究道路,创立了关于动物解放和动物权利的学说。作为动物伦理学领域的权威学者,二者的研究进路有很大不同,辛格是效用主义者,雷根是权利论者,但他们都主张一种比较彻底的动物保护观,主张动物与人类平等,反对为了人类的贪欲和利益而伤害动物。他们的观点给了动物保护以强大的推动力。     

实验动物:有谁在乎我们的生与死?

孟子曾经说过:"君子之于禽兽也,见其生,不忍见其死,闻其声,不忍食其肉。"庄子亦不主张人们费尽心机,设计弓剑、钩网和陷阱等各种技巧装置,用来射鸟、捉鱼和捕兽;反对给马进行火烙剪削的手术。古人尚且如此,今人又是如何做的呢?我们暂且抛开大量人类"施暴"动物的残酷之事不说,     

濒危的动物

[活动设计思路] 大自然中的人与动物、植物之间有着十分密切的关系。植物是很多动 物的食物,动物之间也存在捕食与被捕食的关系,同时人类为了自己生存 的需要,杀死了大量的动物,部分动物、植物从地球上永久地消失了。它 们的消失,会给大自然带来哪些变化呢?人类消灭动植物的方法仅仅是狩 猎吗?可能导致物种濒危的环境因素有哪些呢？如何避免？我们能做些什 么？ 让学生通过下面的活动,在体验中领悟其中的道理,领悟人与自然这 种相互依存的关系有多重要。在活动中,培养学生学会与他人合作、同情 弱小等情感、态度、价值观。     

浅谈防治城市汽车尾气污染之责任

汽车是人类社会进步的产物，是现代社会物质文明的标志之一。但汽车在给人们的生活带来便捷、带来享受，给社会带来财富的同时也给人类生存的大气环境带来了“麻烦”，特别是对大中城市的空气环境质量构成了严重威胁。采取积极有效措施，控制、减少汽车尾气排放污染是保护和改善城市空气环境质量、保证城市可持续发展的当务之急。     

全球气候变暖带来商机

全球气候变暖在给人类生活带来威胁的同时,也给人类提供了一些投资机会,比如,投资开发风能、太阳能等可再生能源。     

美国一电厂办法高 利用火鸡粪发电

平时废弃不用的火鸡粪有了新用途，美国明尼苏达州建造了一个以火鸡粪为愿料的发电厂。     

桑珠日记

"世界动物日"(World Animal Day)——举世同庆人类朋友的节日,源自19世纪意大利修道士坚·弗朗西斯的倡议。他长期生活在阿西西岛上的森林中,热爱动物并和动物们建立了"兄弟姐妹"般的关系。他要求村民们在10月4日这天"向献爱心给人类的动物们致谢"。爱护动物已成为目前世界十大环保工作之一。中国从1997年开始纪念"世界动物日",北京各界环保志愿者自发成立了民间环保慈善机构——首都爱护动物协会,积极开展各种爱护动物的公益活动。本刊编辑部谨以此文献给关爱野生动物,为保护野生动物事业做出贡献的环境保护工作者。     

Integrating fire management into land-use planning: A multiple-use management research,development, and applications program

The traditional view of fire as a destructive agent requiring immediate suppression is giving way to the view that fire can and should be used to meet land management goals. Thus,fire control is being replaced by the more general concept offire management, which is based on the need to integrate fire policy with land management objectives. The social, economic, and ecologic effects of fire must be evaluated in the selection of land management alternatives.The activities of fire management organizations—fire prevention, control, and use of fire—must respond to needs of land management. Many agencies have developed fire organizations as separate entities that set their own objectives. The many land and resource managers who have recognized the need to incorporate fire considerations into land-use planning have so far lacked the techniques to do so.As a natural process, fire has an important function in forest and range ecosystems. Fire can greatly influence the quantity and quality of resource outputs; it is a two-edged sword that can either harm or benefit our goals, depending upon the complex effects of fire and the nature of our wants.The Fire in Multiple-Use Management Research, Development, and Applications (RD&A) Program was initiated by the U.S. Department of Agriculture, Forest Service, at the Northern Forest Fire Lab in Missoula to assist land managers. This profile explains what an RD&A program is; discusses its mission, goals, and approach to the problem; and tells why the approach involves federal laboratories, universities, and private research foundations.     

Restoring fire as an ecological process in shortgrass prairie ecosystems: initial effects of prescribed burning during the dormant and growing seasons

Prior to Anglo-European settlement, fire was a major ecological process influencing the structure, composition and productivity of shortgrass prairie ecosystems on the Great Plains. However during the past 125 years, the frequency and extent of grassland fire has dramatically declined as a result of the systematic heavy grazing by large herds of domestic cattle and sheep which reduced the available levels of fine fuel and organized fire suppression efforts that succeeded in altering the natural fire regime. The greatly diminished role of recurrent fire in these ecosystems is thought to be responsible for ecologically adverse shifts in the composition, structure and diversity of these grasslands, leading specifically to the rise of ruderal species and invasion by less fire-tolerant species. The purpose of this study was to evaluate the ecological effects of fire season and frequency on the shortgrass prairie and to determine the means by which prescribed fire can best be restored in this ecosystem to provide the greatest benefit for numerous resource values. Plant cover, diversity, biomass and nutrient status, litter cover and soil chemistry were measured prior to and following fire treatments on a buffalograss-blue grama shortgrass prairie in northeastern New Mexico. Dormant-season fire was followed by increases in grass cover, forb cover, species richness and concentrations of foliar P, K, Ca, Mg and Mn. Growing-season fire produced declines in the cover of buffalograss, graminoids and forbs and increases in litter cover and levels of foliar P, K, Ca and Mn. Although no changes in soil chemistry were observed, both fire treatments caused decreases in herbaceous production, with standing biomass resulting from growing-season fire approximately 600 kg/ha and dormant-season fire approximately 1200 kg/ha, compared with controls approximately 1800 kg/ha. The initial findings of this long-term experiment suggest that dormant-season burning may be the preferable method for restoring fire in shortgrass prairie ecosystems where fire has been excluded for a prolonged time period.     

Fire hazard after prescribed burning in a gorse shrubland: implications for fuel management

Prescribed burning is commonly used to prevent accumulation of biomass in fire-prone shrubland in NW Spain. However, there is a lack of knowledge about the efficacy of the technique in reducing fire hazard in these ecosystems. Fire hazard in burned shrubland areas will depend on the initial capacity of woody vegetation to recover and on the fine ground fuels existing after fire. To explore the effect that time since burning has on fire hazard, experimental tests were performed with two fuel complexes (fine ground fuels and regenerated shrubs) resulting from previous prescribed burnings conducted in a gorse shrubland (Ulex europaeus L.) one, three and five years earlier. A point-ignition source was used in burning experiments to assess ignition and initial propagation success separately for each fuel complex. The effect of wind speed was also studied for shrub fuels, and several flammability parameters were measured. Results showed that both ignition and initial propagation success of fine ground fuels mainly depended on fuel depth and were independent of time since burning, although flammability parameters indicated higher fire hazard three years after burning. In contrast, time since burning increased ignition and initial propagation success of regenerated shrub fuels, as well as the flammability parameters assessed, but wind speed had no significant effect. The combination of results of fire hazard for fine ground fuels and regenerated shrubs according to the variation in relative coverage of each fuel type after prescribed burning enabled an assessment of integrated fire hazard in treated areas. The present results suggest that prescribed burning is a very effective technique to reduce fire hazard in the study area, but that fire hazard will be significantly increased by the third year after burning. These results are valuable for fire prevention and fuel management planning in gorse shrubland areas.     

Analysis of the prescribed burning practice in the pine forest of northwestern Portugal

The ignition of low-intensity fires in the dormant season in the pine stands of north-western Portugal seeks to reduce the existing fuel hazard without compromising site quality. The purpose of this study is to characterise this practice and assess its effectiveness, based on information resulting from the normal monitoring process at the management level, and using operational guidelines, fire behaviour models and a newly developed method to classify prescribed fire severity. Although the region's humid climate strongly constrains the activity of prescribed fire, 87% of the fires analysed were undertaken under acceptable meteorological and fuel moisture conditions. In fact, most operations achieved satisfactory results. On average, prescribed fire reduces by 96% the potential intensity of a wildfire occurring under extreme weather conditions, but 36% of the treated sites would still require heavy fire fighting resources to suppress such fire, and 17% would still carry it in the tree canopy. Only 10% of the prescribed burns have an excessive impact on trees or the forest floor, while 89% (normal fire weather) or 59% (extreme fire weather) comply with both ecological integrity maintenance and wildfire protection needs. Improved planning and monitoring procedures are recommended in order to overcome the current deficiencies.     

Slash fire hazard analysis on the Siskiyou National Forest

Potential increase in fire hazard as a result of timber harvesting is a concern of forest managers throughout the United States. Treating fuels can help reduce unacceptable fire hazards. To evaluate alternative fuel treatments, managers need to know their effects on fire hazard. A decision analysis approach to estimating fire hazard in terms of expected burned area was applied to a watershed in the Siskiyou National Forest (Oregon). Three treatment alternatives (do nothing and two levels of yarding unmerchantable material) were evaluated, and the effects of the treatments were projected over a 90-yr period. Initially, the effects of applying a treatment are small. After 50 years of treatment, the most intense alternative can be expected to show almost a 50% reduction in burned area compared to no treatment. The procedure also estimates burned are by fire size and fire intensity classes. Managers may find this useful for estimating expected fire effects associated with a particular fuel treatment regime.     

A heuristic expert system for forest fire guidance in Greece

Forests and forestlands are common inheritance for all Greeks and a piece of the national wealth that must be handed over to the next generations in the best possible condition. After 1974, Greece faces a severe forest fire problem and forest fire forecasting is the process that will enable the Greek ministry of Agriculture to reduce the destruction. This paper describes the basic design principles of an Expert System that performs forest fire forecasting (for the following fire season) and classification of the prefectures of Greece into forest fire risk zones. The Expert system handles uncertainty and uses heuristics in order to produce scenarios based on the presence or absence of various qualitative factors. The initial research focused on the construction of a mathematical model which attempted to describe the annual number of forest fires and burnt area in Greece based on historical data. However this has proven to be impossible using regression analysis and time series. A closer analysis of the fire data revealed that two qualitative factors dramatically affect the number of forest fires and the hectares of burnt areas annually. The first is political stability and national elections and the other is drought cycles. Heuristics were constructed that use political stability and drought cycles, to provide forest fire guidance. Fuzzy logic was applied to produce a fuzzy expected interval for each prefecture of Greece. A fuzzy expected interval is a narrow interval of values that best describes the situation in the country or a part of the country for a certain time period. A successful classification of the prefectures of Greece in forest fire risk zones was done by the system, by comparing the fuzzy expected intervals to each other. The system was tested for the years 1994 and 1995. The testing has clearly shown that the system can predict accurately, the number of forest fires for each prefecture for the following year. The average accuracy was as high as 85.25% for 1995 and 80.89% for 1994. This makes the Expert System a very important tool for forest fire prevention planning.     

Predicting streamflow response to fire-induced landcover change: implications of parameter uncertainty in the MIKE SHE model

Fire is a primary agent of landcover transformation in California semi-arid shrubland watersheds, however few studies have examined the impacts of fire and post-fire succession on streamflow dynamics in these basins. While it may seem intuitive that larger fires will have a greater impact on streamflow response than smaller fires in these watersheds, the nature of these relationships has not been determined. The effects of fire size on seasonal and annual streamflow responses were investigated for a medium-sized basin in central California using a modified version of the MIKE SHE model which had been previously calibrated and tested for this watershed using the Generalized Likelihood Uncertainty Estimation methodology. Model simulations were made for two contrasting periods, wet and dry, in order to assess whether fire size effects varied with weather regime. Results indicated that seasonal and annual streamflow response increased nearly linearly with fire size in a given year under both regimes. Annual flow response was generally higher in wetter years for both weather regimes, however a clear trend was confounded by the effect of stand age. These results expand our understanding of the effects of fire size on hydrologic response in chaparral watersheds, but it is important to note that the majority of model predictions were largely indistinguishable from the predictive uncertainty associated with the calibrated model - a key finding that highlights the importance of analyzing hydrologic predictions for altered landcover conditions in the context of model uncertainty. Future work is needed to examine how alternative decisions (e.g., different likelihood measures) may influence GLUE-based MIKE SHE streamflow predictions following different size fires, and how the effect of fire size on streamflow varies with other factors such as fire location.     

Info-Gap Decision Theory for Assessing the Management of Catchments for Timber Production and Urban Water Supply

While previous studies have examined how forest management is influenced by the risk of fire, they rely on probabilistic estimates of the occurrence and impacts of fire. However, nonprobabilistic approaches are required for assessing the importance of fire risk when data are poor but risks are appreciable. We explore impacts of fire risk on forest management using as a case study a water catchment in the Australian Capital Territory (ACT) (southeastern Australia). In this forested area, urban water supply and timber yields from exotic plantations are potential joint but also competing land uses. Our analyses were stimulated by extensive wildfires in early 2003 that burned much of the existing exotic pine plantation estate in the water catchment and the resulting need to explore the relative economic benefits of revegetating the catchment with exotic plantations or native vegetation. The current mean fire interval in the ACT is approximately 40 years, making the establishment of a pine plantation economically marginal at a 4% discount rate. However, the relative impact on water yield of revegetation with native species and pines is very uncertain, as is the risk of fire under climate change. We use info-gap decision theory to account for these nonprobabilistic sources of uncertainty, demonstrating that the decision that is most robust to uncertainty is highly sensitive to the cost of native revegetation. If costs of native revegetation are sufficiently small, this option is more robust to uncertainty than revegetation with a commercial pine plantation.