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171.
Bayramin I Basaran M Erpul G Canga MR 《Environmental monitoring and assessment》2008,140(1-3):249-265
There has been increasing concern in highlands of semiarid Turkey that conversion of these systems results in excessive soil
erosion, ecosystem degradation, and loss of sustainable resources. An increasing rate of land use/cover changes especially
in semiarid mountainous areas has resulted in important effects on physical and ecological processes, causing many regions
to undergo accelerated environmental degradation in terms of soil erosion, mass movement and reservoir sedimentation. This
paper, therefore, explores the impact of land use changes on land degradation in a linkage to the soil erodibility, RUSLE-K,
in Cankiri–Indagi Mountain Pass, Turkey. The characterization of soil erodibility in this ecosystem is important from the
standpoint of conserving fragile ecosystems and planning management practices. Five adjacent land uses (cropland, grassland,
woodland, plantation, and recreational land) were selected for this research. Analysis of variance showed that soil properties
and RUSLE-K statistically changed with land use changes and soils of the recreational land and cropland were more sensitive
to water erosion than those of the woodland, grassland, and plantation. This was mainly due to the significant decreases in
soil organic matter (SOM) and hydraulic conductivity (HC) in those lands. Additionally, soil samples randomly collected from
the depths of 0–10 cm (D
1) and 10–20 cm (D
2) with irregular intervals in an area of 1,200 by 4,200 m sufficiently characterized not only the spatial distribution of
soil organic matter (SOM), hydraulic conductivity (HC), clay (C), silt (Si), sand (S) and silt plus very fine sand (Si + VFS)
but also the spatial distribution of RUSLE-K as an algebraically estimate of these parameters together with field assessment
of soil structure to assess the dynamic relationships between soil properties and land use types. In this study, in order
to perform the spatial analyses, the mean sampling intervals were 43, 50, 64, 78, 85 m for woodland, plantation, grassland,
recreation, and cropland with the sample numbers of 56, 79, 72, 13, and 69, respectively, resulting in an average interval
of 64 m for whole study area. Although nugget effect and nugget effect–sill ratio gave an idea about the sampling design adequacy,
the better results are undoubtedly likely by both equi-probable spatial sampling and random sampling representative of all
land uses. 相似文献
172.
The long-term behavior of 90Sr was investigated from 1987 to 1997 in fifteen lakes in southern and central Finland following the 1986 Chernobyl accident. Both water and fish samples (perch, pike, vendace) were analyzed. 90Sr stays long in the freshwater ecosystem; the observed half-lives during the study period were generally around 10 years in water and even longer in fish. One lake exhibited very different behavior for 90Sr, with elevated levels in fish and water and very short observed half-life in fish, less than 2 years. Concentration factors of 90Sr in fish (Bqkg−1 f.w. in fish/Bqkg−1 in water) among the studied lakes significantly correlated with both the Ca concentration and electrical conductivity of the water. More 90Sr was transferred into fish in lakes with a low electrical conductivity and a low Ca concentration. Among other water parameters evaluated were pH, color, total nitrogen, and phosphorus. 相似文献
173.
174.
IEC61508标准指导城市轨道交通设备安全功能指标实施 总被引:1,自引:0,他引:1
IEC61508标准提出电气/电子/叮编程电子(E/E/PE)安全相关系统的功能安全,成为了电气/电子/可编程电子(E/E/PE)安全相关系统的功能安全的基本和核心标准。城市轨道交通设备越来越多地采用了电气/电子/可编程电子系统(E/E/PES),确保这些设备功能安全指标的落实是工程建设,以及运营安全的一个重要组成环节。 相似文献
175.
It is well known that atmospheric electrical conductivity is mainly due to the presence of small ions. Near the surface of the earth, radon and its daughter products predominantly produce small ions. In the presence of aerosol particles, the small ion concentration is reduced due to attachment of small ions to aerosol particles which decreases mobility and conductivity in the atmosphere. The ion pair production rate is estimated from the measured radon and its progeny concentrations and correlated with electrical conductivity of the atmosphere. Measurement of concentrations of suspended particulate matter (SPM), SO2, and NO2 of air was also carried out. Data showed that reduced electrical conductivity was related to concentration of airborne SPM. 相似文献
176.
机电产品可靠性研究与探讨 总被引:1,自引:0,他引:1
机电产品越来越广泛地应用于社会各个领域,随着自动化、小型化程度的提高,很多机电产品结构越来越复杂,并且其使用条件也越来越严酷,由此产生的产品可靠性问题必然越来越多,可靠性技术也越来越受到重视。本文针对机电产品,从可靠性管理、可靠性设计和分析、可靠性试验和评定三个方面,对可靠性研究工作进行初步探讨。 相似文献
177.
Applicability of grid-net detection system for landfill leachate and diesel fuel release in the subsurface 总被引:1,自引:0,他引:1
The grid-net system estimating the electrical conductivity changes was evaluated as a potential detection system for the leakage of diesel fuel and landfill leachate. Aspects of electrical conductivity changes were varied upon the type of contaminant. The electrical conductivity in the homogeneous mixtures of soil and landfill leachate linearly increased with the ionic concentration of pore fluid, which became more significant at higher volumetric water contents. However, the electrical conductivity in soil/diesel fuel mixture decreased with diesel fuel content and it was more significant at lower water contents. The electrode spacing should be determined by considering the type of contaminant to enhance the electrode sensitivity especially when two-electrode sensors are to be used. The electrode sensitivity for landfill leachate was constantly maintained regardless of the electrode spacings while that for the diesel fuel significantly increased at smaller electrode spacings. This is possibly due to the fact that the insulating barrier effect of the diesel fuel in non-aqueous phase was less predominant at large electrode spacing because electrical current can form the round-about paths over the volume with relatively small diesel fuel content. The model test results showed that the grid-net detection system can be used to monitor the leakage from waste landfill and underground storage tank sites. However, for a successful application of the detection system in the field, data under various field conditions should be accumulated. 相似文献
178.
Acidity and conductivity of Pinus massoniana bark as indicators to atmospheric acid deposition in Guangdong, China 总被引:2,自引:0,他引:2
Introduction The ever-increasing development of human activities has given significant rise to atmospheric pollutants which have negative impacts on natural ecosystems, as for example the severe decrease of the forests (Soikkeli, 1981; Hirano and Hijii, 1… 相似文献
179.
Status quo of e-waste management in mainland China 总被引:2,自引:1,他引:2
Jinhui Li Baoguo Tian Tongzhou Liu Hao Liu Xuefeng Wen Shun'ichi Honda 《Journal of Material Cycles and Waste Management》2006,8(1):13-20
In China, the use and obsolescence of both electronic and electrical equipment have increased rapidly in recent years. China
has also begun to take measures to cope with this problem since it began experiencing a rapid process of industrialization
and urbanization in the 1990s. In this paper, the profile of the electrical and electronic waste (e-waste) problem in China
is depicted from such aspects as domestic e-waste and imported e-waste, along with their recycling systems, policies, and
regulations. Based on statistics of the consumption of major household appliances and personal computers, a forecast is made
of the numbers of obsolete major household appliances and personal computers. The results show that currently the number of
electrical and electronic products in use in China is tremendous. An investigation on household appliances and personal computers
in Beijing was made to assess the use and obsolescence of these products. Also, the legal issues relating to e-waste in China
are summarized, and these will be the juristic foundation for the solution of e-waste problems. 相似文献
180.