Extraction capacity and the optimal order of extraction

The least-cost-first extraction rule for deposits with different extraction costs previously has been shown to be invalid in general equilibrium. This paper demonstrates that this rule also does not hold in partial equilibrium when extraction capacity is limited. Necessary and sufficient conditions for several surprising extraction orders are presented. If extraction from a high-cost resource is constrained, it may be optimal to begin extraction from a high-cost deposit (or backstop) strictly before extracting from a lower-cost deposit. If extraction from a low-cost resource is limited, it may be optimal to exhaust a high-cost deposit strictly before the low-cost deposit is exhausted or to abandon extraction temporarily from a high-cost deposit and then to exhaust it later. The analysis demonstrates how extraction constraints affect the order of extraction and shows that certain cost reversals are caused by limited extraction capacity rather than by the general equilibrium definition of extraction costs.     

Set-up costs and the existence of competitive equilibrium when extraction capacity is limited

Although set-up costs are prevalent and substantial in natural resource extraction, it is known that a Walrasian competitive equilibrium cannot exist in simple extraction models with set-up costs. This paper demonstrates that this result is sensitive to the assumption of unlimited extraction capacity and derives sufficient conditions for existence. An equilibrium exists if extraction is limited such that each firm earns sufficient surplus to cover its set-up costs or if firms choose extraction capacity subject to non-increasing returns. The resulting competitive equilibrium price either grows at the rate of interest when total extraction is below industry capacity or is constant when industry capacity is fully utilized. In the equilibrium, identical deposits are opened simultaneously, and set-up costs for new deposits are incurred when the industry has excess capacity rather than when capacity is fully utilized.     

Sequential development and exploitation of an exhaustible resource: do monopoly rights promote conservation?

This paper explores the problem of sequential exploitation of exhaustible resources by a monopolist, when a setup cost must be incurred to access the next pool. Under certain circumstances, the monopolist will always follow a more conservationist path of extraction and delay the introduction of new resource pools compared to a social planner. However, with other forms of consumer demand, the monopolist may exhaust the resource more quickly, especially if many new options will follow. These results may apply especially to depletable resources like antibiotics or biotech products, for which significant research and development costs are required, followed by monopoly rights conferred by patents.     

碱性印染废水用于燃煤锅炉烟气脱硫除尘技术

介绍了当前国内利用碱性印染废水进行燃煤锅炉烟气湿法脱硫除尘的技术,并对其进行了技术经济分析。     

气相色谱法测定大气中烯烃的研究

采用硅胶－ＡｇＮＯ３富集样品,热解吸进样,气相色谱法分析大气中的烃一,富集过程在常温下进行。当富集样品０．１Ｌ时,乙烯,丙烯,丁二烯的最小检有度分别为０．０００６ｍｇ／ｍ＾３,０．００１ｍｇ／ｍ＾３、０．００４ｍｇ／ｍ＾３,相对标准偏差小于６％,加标回收率９７％－１０９％。     

高温煤气脱硫剂研究进展

系统地介绍了国外高温煤气脱硫剂的研究开发现状,指出我国重点研究开发铁系、锰系、锌系、铜系和钙系脱硫剂。     

Variations of denitrification in a farming catchment area

We measured denitrification at 15 sites during 1 year in a agricultural catchment in Brittany, France. Our objective was to assess the relative importance of heterotrophic denitrification on the fate of excess nitrogen at the catchment scale, and to quantify the relative importance of riparian areas on the N₂O emissions. Using the C₂H₂ inhibition technique, denitrification rate on soil core and denitrifying enzyme activity (DEA) were each determined, for samples taken from two soil layers: 0–20 and 20–40 cm. Denitrification rates, ranging from 0 to 417 mg N m⁻² d⁻¹, were significantly higher in riparian areas than for hillslopes (median of 24.87 against 10.38 mg N m⁻² d⁻¹). However, since denitrification rates are significant in the hillslope and given that hillslope surface area is much greater (79% of catchment surface), this domain could be responsible for half of the overall denitrified nitrogen (N). Also, the 20–40 cm deep soil layer was found to account for more than 46% of the denitrification. The DEA indicates the potential for denitrifying activity by the soil under non-limiting conditions, measured values ranged from 76.48 to 530.63 ng N g⁻¹ dry soil h⁻¹. The ratio N₂O/(N₂O + N₂) was about 60% with no clear spatial or temporal trends. Soil moisture appeared to be the main limiting factor for denitrification at the field scale. The results suggest that, for this catchment, denitrification is a major route for nitrogen removal, but a significant proportion of this removal occurs as N₂O.     

气浮+CASS组合工艺在肉鸡屠宰废水处理中的应用

屠宰废水是一种常见的食品加工废水,废水中有机污染物浓度较高,且含有脂肪、蛋白质等大分子有机物和毛发、动物内脏等杂物.絮凝气浮 CASS组合工艺在铁岭某肉鸡屠宰公司废水处理工程应用中,取得了较为显著的效果,CODcr去除率98%,BOD5去除率98%,SS去除率98%,氨氮去除率58%,动植物油去除率91%;出水水质均满足GB13457-92<肉类加工工业水污染物排放标准>要求.该工艺具有投资少、操作简单、处理效果好、便于管理的特点,易于在同类食品加工废水处理中推广应用.     

半干法烟道气脱硫影响因素的理论分析

建立了半干法烟气脱硫的理论模型,分析了各种影响因素,以反应时间和液滴干燥时间为基础数据,优化出液滴在脱硫干燥塔内的停留时间,由停留时间确定脱硫塔高度,由处理的烟气流量确定塔径.     

活性炭和天然锰砂混合处理镀锌废水的研究

介绍用活性炭和天然锰砂作反应剂交互作用处理镀水的研究，实验结果表明，活性炭：天少＝２：３，加鼓氧，静置后过滤，废水处理效率更好，Ｚｎ＾２＋的去除率达９９．８％，Ｆｅ＾３＋去除率达９９．６％，废水ＰＨ值上升到６．０达到国家废水排放标准。