矿井回风流中低浓度瓦斯利用现状及前景

矿井回风流瓦斯直接排放到大气中 ,不仅造成了资源的浪费 ,而且加剧了温室效应 ,如何利用低浓度瓦斯是迫切需要研究的课题。介绍了矿井瓦斯利用存在的主要问题 ,介绍了作为辅助燃料和主要燃料在国外的研究利用情况 ,重点介绍了TFRR的原理、反应过程及热量的回收利用方式 ,并对低浓度甲烷的应用前景进行了展望。     

黑龙江大兴安岭林区森林草类可燃物潜在能量研究

黑龙江大兴安岭林区森林草类植被能量释放主要取决于可燃物的生物量和发热量，可燃物的能量与含水率有着密切关系，而可燃物的含水率又与气角要素有着相关性。在对大兴安岭樟子松林、柞木林、山杨林、白桦林、落叶松、草类和采伐迹地等不同可燃物类型设置标准地并进行可燃物生物量调查的基础上，收集整理防火期内气象资料，分析可燃物含水率与气象因子的关系。结果表明，雨量多，相对湿度大，气温低，风小，含水率就多，相反则少；不同可燃物的发热量和生物量不同，潜在能量也不同，火的强度也不一样；不同可燃物类型，由于树种组成、年龄以及立地条件等不同，能量释放和火强度等也大不相同。     

汽车排放标准与改进燃料品质降低排放污染

本文综述了美国、日本、欧洲经济委员会（ＥＣＥ）及中国的汽车（主要是汽油车）排放标准；汽车排放与燃料品质有直接关系，通过改进燃料品质如使用无铅汽油，含氧燃料和替代燃料以及降低汽油中芳烃及硫含量等都能改善汽车排放污染。     

Assessing the impact of CO2 emission control scenarios in Finland on radiative forcing and greenhouse effect

Carbon dioxide emission reduction scenarios for Finland are compared with respect to the radiative forcing they cause (heating power due to the absorption of infrared radiation in the atmosphere). Calculations are made with the REFUGE system model using three carbon cycle models to obtain an uncertainity band for the development of the atmospheric concentration. The future emissions from the use of fossil fuels in Finland are described with three scenarios. In the reference scenario (business-as-usual), the emissions and the radiative forcing they cause would grow continuously. In the scenario of moderate emission reduction, the emissions would decrease annually by 1% from the first half of the next century. The radiative forcing would hardly decrease during the next century, however. In the scenario of strict emission reductions, the emissions are assumed to decrease annually by 3%, but the forcing would not decrease until approximately from the middle of the next century depending on the model used. Still, in the year 2100 the forcing would be considerably higher than the forcing in 1990. Due to the slow removal of CO₂ from the atmosphere by the oceans, it is difficult to reach a decreasing radiative forcing only by limiting fossil CO₂ emissions. The CO₂ emissions from fossil fuels in Finland contribute to the global emissions presently by about 0.2%. The relative contribution of Finnish CO₂ emissions from fossil fuels to the global forcing due to CO₂ emissions is presently somewhat less than 0.2% due to relatively smaller emissions in the past. The impact of the nonlinearity of both CO₂ removal from the atmosphere and of CO₂ absorption of infrared radiation on the results is discussed.     

Blocking pipelines,unsettling environmental justice: from rights of nature to responsibility to territory

ABSTRACT

Indigenous peoples are among the most affected by environmental injustices globally, however environmental justice theory has not yet meaningfully addressed decolonisation and the resistance of Indigenous communities against extractivism in the settler-colonial context. This paper suggests that informing environmental justice through decolonial analysis and decolonising practices can help transcend the Western ontological roots of environmental justice theories and inform a more radical and emancipatory environmental justice. The Unist’ot’en Resistance and Action Camp blocking pipelines in northwestern British Columbia, Canada, their “Reimagined Free Prior and Informed Consent protocol” and the Delgamuukw case are described to discuss limitations of the state and legal framework for accommodating a decolonial and transformative environmental justice. A decolonial analysis informed by these two moments of Wet’sewet’ten history suggests limits and adaptations to the trivalent EJ framework based on recognition, participation and distribution. It is argued that a decolonising and transformative approach to environmental justice must be based on self-governing authority, relational ontologies of nature and epistemic justice and the unsettling of power through the assertion of responsibility and care through direct action. This discussion is placed in the context of the expansion of the concept of ecological rights, for example through the enshrining of the “Rights of Nature” in the constitutions of countries such as Bolivia and Ecuador, to highlight the Inherent tensions in the translation of Indigenous cosmo-visions into legal systems based on universalist values.     

Impact of nonuniform reactant flow rate on the performance of proton exchange membrane fuel cell stacks

ABSTRACT

In this study, a proton exchange membrane (PEM) fuel cell stack composed of five cells in series is numerically investigated to study the impact of the nonuniform reactant flow rate on the performance of the stack. A comparison of the water concentration, temperature, reaction heat source, and current density of change rule of two groups of fuel cell stacks with uniform and nonuniform reactant flow rate reveals the performance degradation mechanism caused by nonuniform reactant flow. The results indicate that while operating under low-voltage conditions, the nonuniform reactant flow rate will cause the accumulation of excess liquid water near the PEM that is near the cathode exhaust outlet, and the local area reacts strongly on the catalyst, whereas the local area reacts slowly. When the average voltage of the stack is 0.55 V, the current density under the nonuniform reactant flow rate condition is 12.9% lower than that of the uniform reactant flow rate condition. In the case of uniform and nonuniform reactant flow rate at low current densities, the performance difference is not evident, but it is expected to be pronounced with the increase in current density. The simulation results are compared with the experimental data reported in the literature through a polarization curve, and they turn out to be well correlated with the experimental results.     

The management implications of fine fuel dynamics in Bushlands Surrounding Hobart, Tasmania

Hobart's bushlands consist of eight distinct vegetation types ranging from open woodland to wet forest. Fine fuel accumulation characteristics are distinctive across this range of vegetation types and mostly seem to conform to the function W_t = W_ss(1−e^−kt)+ l·92(e^−kt), although there is considerable scatter around the lines of best fit in many types.This information contributes to determining the applicability and appropriate frequency of controlled burning as a means of reducing fuels to protect life and property from wildfire. Regular burning of grassy vegetation should ensure relatively safe zones within the urban/bush matrix. It is likely that burning heathy forest types at frequencies that would ensure safe fuel loads would be ecologically detrimental. It would be difficult and futile to use fuel reduction burning in wet forest types as a means of protecting life and property. The fuel accumulation characteristics and the existing ecological knowledge of Allocasuarina verticillata shrubland suggests that fuel reduction burning would be counter-productive in this vegetation type.     

WATER YIELD IMPROVEMENT BY VEGETATION MANAGEMENT1

ABSTRACT: Vegetation management aimed at increasing the amount of usable water yield from precipitation falling on upstream watersheds may be one alternative for supplementing water supplies. Indications are that water yields can be increased within a multiple-use framework, which can benefit or at least be compatible with other natural resource objectives. Through changes in vegetation on a watershed, it is possible to reduce evaporation losses only slightly but significantly increase streamflow runoff. In an assessment of potentials for water yield improvement in Arizona, experimental studies on various vegetation zones are reviewed. Because of either limited acreage or limited rainfall, the alpine, grassland, aspen, and desert shrub vegetation zones are not realistic management areas for Arizona. Furthermore, manipulation of pinyon-juniper woodlands does not appear promising at this time. Conversion of chaparral to grasses and forbs does appear to be a possible treatment for water yield improvement, as well as various silvicultural treatments of mixed conifer and ponderosa pine forests. Streamflow increases are given for experiments in chaparral, mixed conifer, and ponderosa pine vegetation zones. However, complete information on possible constraints for these zones is not currently available. Specific assessment of water yield management options for riparian vegetation is difficult to make, due to incomplete knowledge of water yield changes and other constraints for this vegetation zone. Prior to the final adoption of management practices, results of experimental work must be coupled with economic and social considerations.     

SEDIMENT CHEMISTRY AS INFLUENCED BY VEGETATION AND BEDROCK IN THE SOUTHWESTERN UNITED STATES1

ABSTRACT We hypothesized that sediment from small watersheds with uniform bedrock and a single vegetative community would have uniform chemical characteristics for the sand and fine (silt and clay) size fractions. Channel sediment was collected from three vegetative communities (spruce-fir, mixed conifer, and Ponderosa pine), each on four bedrock types (basalt, limestone, sandstone, and granite), and analyzed for digestable Ca, Mg, Na, K, Cu, Mn, Fe, Zn; total N and P; extractable Ca, Mg, K; cation exchange capacity; and organic matter. With the exception of organic matter content in the sand size fraction, either vegetation, bedrock, or their interaction were significant in explaining the observed variation for all analyses in both size fractions. Replicate studies of sites with similar bedrock and vegetation combinations are needed to determine if each watershed has similar or unique sediment chemistry.     

BIOLOGICAL INDICATORS AND BIOLOGICAL EFFECTS OF ESTUARINE/COASTAL POLLUTION1

ABSTRACT: Sustained interest in and concern about the health status of the aquatic environment has resulted in extensive research focused on (1) effects of pollution on survival, growth, and reproduction of resource species at all life stages; (2) diseases of fish and shellfish, as they may be related to pollution and as they may serve as indicators of environmental stress; and (3) contaminant body burdens in fish and shellfish - their effects on the aquatic animals and their potential effects on humans. Effects, lethal and sublethal, of pollutants on life history stages of fish and shellfish have been documented, as have impacts on local stocks in badly degraded habitats, but as yet there has been no adequate quantitative demonstration of effects on entire aquatic species - probably because of the difficulty in sorting out relative effects of the many environmental factors that influence abundance. Sublethal effects, especially those that result in disease, have been examined intensively, and some diseases and disease syndromes have been associated statistically with pollution. Other pollution indicators (biochemical, physiological, genetic, behavioral, and ecological) have also received some attention, as have body burdens of contaminants in aquatic species. Research, especially that conducted during the past decade, has done much to clarify the many pathways and toxic effects of contaminants on aquatic animals, and has also helped to identify mechanisms for survival of fish and shellfish in the presence of environmental changes caused by human activities.