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961.
The theory of collective action has been extensively used to explain the relationship between common-based property regimes and the conservation of natural resources. However, there are two key components of the theory that literature reports as puzzles in which no consensus exists about their effect on the performance of common-pool resources. These are group size and heterogeneity. This study analyzes the effects of these two key components on the effectiveness of community-based forestry, called ejidos, to protect their forest resources in northern Mexico. We used a multinomial logit model to determine the contribution of 16 explanatory variables to the dependent variable, a measure of success of ejidos defined by the presence of deforested, degraded, or forested conditions. The results show that corn yield, marginality, percent of forest area, total population, a forest value index, distance to markets, roads and towns, were all statistically significant in driving deforested conditions. Deforestation becomes more attractive for poor communities and as corn yield and distance to towns, roads, and markets decrease. In general, group size and heterogeneity had no significant effects on the presence of deforested conditions. Deforestation is driven by resource-specific characteristics, such as location and soil productivity, not by ejidos' attributes, such as total area or number of members. We argue that current institutional policies focusing on the structure of property right arrangements should be shifted (1) to provide better technology for land cultivation; (2) to reduce the marginality problem in poor communities; and (3) to strengthen local institutions. 相似文献
962.
Water quality modeling is an ideal tool for simulating physical, chemical, and biological changes in aquatic systems. It has been utilized in a number of GIS-based water quality management and analysis applications. However, there is considerable need for a decision-making process to translate the modeling result into an understandable form and thereby help users to make relevant judgments and decisions. This paper introduces a water quality index termed QUAL2E water quality loading index (QWQLI). This new WQI is based on water quality modeling by QUAL2E, which is a popular steady-state model for the water quality of rivers and streams. An experiment applying the index to the Sapgyo River in Korea was implemented. Unlike other WQIs, the proposed index is specifically used for simulated water quality using QUAL2E to mainly reflect pollutant loading levels. Based on the index, an iterative modeling-judgment process was designed to make decisions to decrease input pollutants from pollutant sources. Furthermore, an indexing and decision analysis can be performed in a GIS framework, which can provide various spatial analyses. This can facilitate the decision-making process under various scenarios considering spatial variability. The result shows that the index can evaluate and classify the simulation results using QUAL2E and that it can effectively identify the elements that should be improved in the decision-making process. In addition, the results imply that further study should be carried out to automate algorithms and subsidiary programs supporting the decision-making process. 相似文献
963.
Hyun-Jung Choi Hwa Woon Lee Kyoung-Hee Sung Min-Jung Kim Yoo-Keun Kim Woo-Sik Jung 《Atmospheric environment (Oxford, England : 1994)》2009,43(27):4124-4136
In order to incorporate correctly the large or local scale circulation in the model, a nudging term is introduced into the equation of motion. Nudging effects should be included properly in the model to reduce the uncertainties and improve the air flow field. To improve the meteorological components, the nudging coefficient should perform the adequate influence on complex area for the model initialization technique which related to data reliability and error suppression. Several numerical experiments have been undertaken in order to evaluate the effects on air quality modeling by comparing the performance of the meteorological result with variable nudging coefficient experiment. All experiments are calculated by the upper wind conditions (synoptic or asynoptic condition), respectively. Consequently, it is important to examine the model response to nudging effect of wind and mass information. The MM5–CMAQ model was used to assess the ozone differences in each case, during the episode day in Seoul, Korea and we revealed that there were large differences in the ozone concentration for each run.These results suggest that for the appropriate simulation of large or small-scale circulations, nudging considering the synoptic and asynoptic nudging coefficient does have a clear advantage over dynamic initialization, so appropriate limitation of these nudging coefficient values on its upper wind conditions is necessary before making an assessment. The statistical verifications showed that adequate nudging coefficient for both wind and temperature data throughout the model had a consistently positive impact on the atmospheric and air quality field. On the case dominated by large-scale circulation, a large nudging coefficient shows a minor improvement in the atmospheric and air quality field. However, when small-scale convection is present, the large nudging coefficient produces consistent improvement in the atmospheric and air quality field. 相似文献
964.
Valuation of Spatial Configurations and Forest Types in the Southern Appalachian Highlands 总被引:1,自引:0,他引:1
Site-specific estimates of the values of spatial configuration and forest composition are presented. Amenity values of forest
patches are found to vary the most by urban and sprawling development patterns of specific areas and forest types. For example,
smaller patches of deciduous forest are more highly valued in the urban and sprawling areas of Greensboro, North Carolina,
whereas larger patches of deciduous forest are more highly valued in the urban and sprawling areas of Greenville, South Carolina.
Within the Greenville and Greensboro areas, visible landscape complexity is highly valued for deciduous and evergreen forest
patches, whereas lower visible landscape complexity, i.e., smoothly trimmed forest patch boundaries, is highly valued for
mixed forest patches. 相似文献
965.
Application of recycled paper sludge and biomass materials in manufacture of green composite pallet 总被引:1,自引:0,他引:1
Rice straw, rice husk and paper sludge are by-products and industrial waste, and are beneficial resources as raw biomass materials used for manufacturing value-added composite products. We investigated the effect on selected mechanical properties of adding rice straw, rice husk and paper sludge to wood composites to replace wood particles for manufacturing green pallets. Results showed that increasing the contents of rice straw and rice husk dramatically decreased the mechanical strength of the composites. This is because the wax and silicate coating of these materials obstructed the strong bonding with UF resin. When 10 wt.% of wood particle was replaced with 10 wt.% of paper sludge, the wood–paper sludge composites showed similar mechanical properties to those of wood particle. Wood particle can be replaced by 10 wt.% of dried paper sludge in accordance with the minimum requirement recommended by standards in green pallet manufacturing. 相似文献
966.
Junghwan Kim Jinkyung Kim Younghee Lee Wonsub Lim Il Moon 《Journal of Loss Prevention in the Process Industries》2009,22(6):1039-1043
This study develops a modified method of TRIZ to improve safety in chemical process design. This method is modified by the theory of TRIZ, which is inventive problem solving theory, for retrofit design of chemical process considering safety.The original TRIZ is difficult to access to chemical process safety due to inapplicability and ambiguity of terminology in classification of these parameters. It is necessary to be modified TRIZ for chemical process safety. This study reorganized thirty-nine parameters of the TRIZ into six categories such as mechanic, operator, process upset, design, natural hazard and material. The modified TRIZ is tested to jacketed reactor and polyethylene reactor. 相似文献
967.
Methane production potential of leachate generated from Korean food waste recycling facilities: a lab-scale study 总被引:3,自引:0,他引:3
This paper examines the applicability of food waste leachate (FWL) in bioreactor landfills or anaerobic digesters to produce methane as a sustainable solution to the persisting leachate management problem in Korea. Taking into account the climatic conditions in Korea and FWL characteristics, the effect of key parameters, viz., temperature, alkalinity and salinity on methane yield was investigated. The monthly average moisture content and the ratio of volatile solids to total solids of the FWL were found to be 84% and 91%, respectively. The biochemical methane potential experiment under standard digestion conditions showed the methane yield of FWL to be 358 and 478 ml/g VS after 10 and 28 days of digestion, respectively, with an average methane content of 70%. Elemental analysis showed the chemical composition of FWL to be C(13.02)H(23.01)O(5.93)N(1). The highest methane yield of 403 ml/g VS was obtained at 35 degrees C due to the adaptation of seed microorganisms to mesophilic atmosphere, while methane yields at 25, 45 and 55 degrees C were 370, 351 and 275 ml/g VS, respectively, at the end of 20 days. Addition of alkalinity had a favorable effect on the methane yield. Dilution of FWL with salinity of 2g/l NaCl resulted in 561 ml CH(4)/g VS at the end of 30 days. Considering its high biodegradability (82.6%) and methane production potential, anaerobic digestion of FWL in bioreactor landfills or anaerobic digesters with a preferred control of alkalinity and salinity can be considered as a sustainable solution to the present emergent problem. 相似文献
968.
Although production of sewage sludge increases every year, its proper treatment has only been recently raised as a new issue, as current landfill and ocean dumping arrangements are expected to become increasingly difficult to manage in the future. The Korean Ministry of Environment plans to diversify its processing facilities and expand its processing systems by 2011, with the purpose of processing all sludge produced in Korea. According to this plan, incineration (including incineration of municipal wastes) will process 30% of the entire sewage sludge throughout the country in 2011. This study reviews the characteristics of PAH, which is one of the organic substances found in sewage sludge during the incinerating process. The total amount of PAH produced from sewage sludge incineration was found to be 6.103 mg/kg on average, and investigation performed on 16 PAHs of inlets and outlets of the air control devices at five full-scale incineration facilities showed that concentrations of the PAHs on the inlet and on the outlet ranged from 3.926 to 925.748 microg/m(3) and from 1.153 to 189.449 microg/m(3), respectively. In the case of the incineration facility fed with municipal waste (95%) and sewage sludge (5%), the total of the PAH emissions concentration was higher than that found at the incineration facilities used exclusively to treat sewage. The combustion of waste vinyl and plastics contained in municipal waste fed into the facility might contribute to the high levels of PAHs in the stack gas. However more investigation is needed on the production mechanism of PAHs at different operating conditions of the incineration facilities, such as the types of waste, and other relevant factors. 相似文献
969.
Jong-Sub Ban Su-Jin Kim Sang-Hagk Kwon Chae-Gun Phae 《Journal of Material Cycles and Waste Management》2009,11(3):222-228
The reduction and stabilization of biodegradable waste were studied using three operational stages in an aerobic stabilization
system. The system used for mechanical/biological treatment utilized two-shaft screws in multiple box reactors. In the first
operational stage, 50-kg batches of biodegradable waste were charged in each of the three reactors, with peat moss used as
a bulking agent. Analysis revealed that peat moss can be used at this initial stage, based on the observed increase in temperature
and carbon dioxide levels. The second stage of operation involved adding 100 kg/day of biodegradable waste to the first reactor.
It was confirmed that a continuous reaction is possible by the addition of more waste. In the third stage of operation, 20
kg/day of the 100 kg/day of biodegradable waste feed was replaced with material fed back from the third reactor. At this stage,
final product was also removed from the third reactor. The temperature was not controlled, and up to 8%–9% carbon dioxide
was formed, enabling normal activation of decomposition. This three-stage operational test confirmed the expected decomposition
of organic matter and biodegradable materials. The rate of mass reduction calculated for the final product compared with the
input amount was 94.3%, which confirmed that this system would be a useful means for the reduction and stabilization of biodegradable
waste. This study also measured the water content of the material in the reactors: the water content decreased as the reaction
progressed. This indicated that the activation of microorganisms did not occur sufficiently in the second and third reactors.
Future studies of methods to control the internal water content of each reactor should improve the decomposition efficiency. 相似文献
970.
Using a scenario‐based experiment, this study examined how employee attitude and employee communication styles affected managers' reactions to employees' objections to a company policy. In the experiment, employee attitude (cynical versus trusting) and employee communication styles (aggressive versus diplomatic) were manipulated, and managers' reactions to voicing discontent were assessed through a questionnaire. Based on a sample of 185 middle managers working in various organizations in South Korea, the results showed that managers were more likely to engage in social undermining and were less likely to provide social support when cynical (rather than trusting) employees objected to a company policy. Also, attributed motives (i.e., personal attack and health concern) fully mediated the relationship between employee attitude and social support and social undermining. In addition, managers more likely attributed the objection to moral concerns when trusting (rather than cynical) employees communicated in an aggressive manner. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献