首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
This paper examines the scope and limitations of geomorphological investigation of the sites of architectural and engineering works. Various degrees of vulnerability, forms of impact, and types of applied geomorphological response are summarized. Aspects of land development and construction practice that may increase the vulnerability of buildings and structures to geomorphological hazards are discussed. Strengths and weaknesses of the geomorphological input to hazard mitigation are reviewed. Examples are described that show both negative and positive influences exerted by geomorphological site analysis on urban and regional planning for unstable terrains in Italy. It is concluded that societal choice, within the overall matrix of a society's culture (sensu largo), will influence the way in which vulnerability is managed at sites, and hence the scope for utilizing geomorphological analysis of the physical risks.  相似文献   

2.
Lin Liu  Xia Li 《GeoJournal》2014,79(2):127-128
  相似文献   

3.
The impact environment of the Hadean Earth   总被引:1,自引:0,他引:1  
Impact bombardment in the first billion years of solar system history determined in large part the initial physical and chemical states of the inner planets and their potential to host biospheres. The range of physical states and thermal consequences of the impact epoch, however, are not well quantified. Here, we assess these effects on the young Earth's crust as well as the likelihood that a record of such effects could be preserved in the oldest terrestrial minerals and rocks. We place special emphasis on modeling the thermal effects of the late heavy bombardment (LHB) – a putative spike in the number of impacts at about 3.9 Gyr ago – using several different numerical modeling and analytical techniques. A comprehensive array of impact-produced heat sources was evaluated which includes shock heating, impact melt generation, uplift, and ejecta heating. Results indicate that ∼1.5–2.5 vol.% of the upper 20 km of Earth's crust was melted in the LHB, with only ∼0.3–1.5 vol.% in a molten state at any given time. The model predicts that approximately 5–10% of the planet's surface area was covered by >1 km deep impact melt sheets. A global average of ∼600–800 m of ejecta and ∼800–1000 m of condensed rock vapor is predicted to have been deposited in the LHB, with most of the condensed rock vapor produced by the largest (>100-km) projectiles. To explore for a record of such catastrophic events, we created two- and three-dimensional models of post-impact cooling of ejecta and craters, coupled to diffusion models of radiogenic Pb*-loss in zircons. We used this to estimate what the cumulative effects of putative LHB-induced age resetting would be of Hadean zircons on a global scale. Zircons entrained in ejecta are projected to have the following average global distribution after the end of the LHB: ∼59% with no impact-induced Pb*-loss, ∼26% with partial Pb*-loss and ∼15% with complete Pb*-loss or destruction of the grain. In addition to the relatively high erodibility of ejecta, our results show that if discordant ca. 3.9 Gyr old zones in the Jack Hills zircons are a signature of the LHB, they were most likely sourced from impact ejecta.  相似文献   

4.
Silva  Vitor  Schneider  John 《Natural Hazards》2016,83(1):183-199
Carbonation-induced corrosion of the steel reinforcement is the major deterioration factor of the RC infrastructures in urban areas. Carbonation progress in concrete is influenced by the exposure and environmental conditions prevailing at each area. Therefore, the rate of deterioration due to carbonation varies at different areas. Field measurements can quantify this carbonation progress for specific structures and areas. However, the scattered nature of individual field data offers little information to be considered for the assessment of existing structures or the design of new structures. This study aims to bridge this gap and shows that individual field data can be combined to characterise an area using GIS mapping tools. A generated map can depict the variability of carbonation progress with the geographical location. Measurements of the carbonation depth of several buildings at different locations in the Limassol district have been provided by a construction laboratory. Such information can be used to depict the carbonation progress on each structure through the calculation of the carbonation factor and then portray its value using mapping techniques. The result is a corrosion risk map of the Limassol district depicting the variability of carbonation progress with geographical locations. This can be used by engineers and managing authorities as a prediction tool for the initiation of carbonation-induced corrosion in existing structures and also at design stage to set the durability requirements of the concrete cover depth.  相似文献   

5.
在全省组织开展城市环境综合整治活动,用三年左右的时间打一场攻坚战,基本消除城市环境脏乱差现象,着力营造适宜创业发展和生活居住的城市环境,这是山东省委、省政府从全省经济社会发展大局出发,做出的重大战略决策。  相似文献   

6.
天津市经过三十多年的持续发展,经济总量迅猛增长、城市不断扩大、人口不断增长、人民生活水平不断提高的同时,生态环境总体上处于平稳状态,并在某些方面有了明显改善,但是,生态环境总的形势不容乐观:生态环境恶化的威胁依然存在。根据天津市自然地理特征以及地质条件,正确分析其生态现状及存在的问题,提出天津市城市生态建设中有关地质环境课题。  相似文献   

7.
 The economic and environmental consequences of soil nitrogen tests can have significant impacts on agricultural production. Some of these are explored here. The pre-side-dress soil N-test is evaluated for a hypothetical farmer growing corn at the ARS Sustainable Agriculture Demonstration Farm site in southern Maryland. For a farmer not currently using a soil N-test, adoption of this technology can lead to the enhancement of net farm income and the reduction in nitrogen loss to the environment. This will transpire only if the farmer is currently underestimating nitrogen carryover by more than 25% or applying nitrogen fertilizer based solely on an expected plateau-yield goal. Received: 13 February 1997 · Accepted: 13 May 1997  相似文献   

8.
深圳市国土规划地质环境管理体系的构想   总被引:1,自引:0,他引:1  
本文从深圳市地区地质环境现状出发,初步查明了开发区活动断裂及隐伏岩溶地面塌陷等多种地质灾害对城市规划建设的影响和危害。市哒,府有关主管部门借鉴了美国、香港的某些管理经验,结合城市地区的环境地质问题及时采取了治理措施,科学、合理地开展国土规划和城市建设,总结出一套城市国土规划和地质环境管理体系。可供同类型城市管理工作借鉴和参考。  相似文献   

9.
江西省县(市)域生态环境综合评价   总被引:13,自引:0,他引:13  
系统地探讨了江西省生态环境综合评价指标体系,以县(市)区域为基本单元,利用因子分析方法确定各主要生态环境评价因子的权重,进而对全省各县(市)进行生态环境综合评价,确定了生态环境类型,为江西省制定生态经济建设宏观规划,为生态环境的辩证施治,为国民经济发展和环境保护提供客观决策依据。  相似文献   

10.
In this paper, we consider the present-day situation and outlooks of the development of nuclear power generation in Russia and other countries. It was noted that the implementation of the concept of a closed nuclear-fuel cycle accepted in Russia relies on the solution of the problem of the disposal of spent nuclear fuel (SNF) and radioactive waste (RAW). This paper presents the main results of investigations focused on the development of radiation-safe methods of manufacturing nuclear fuel elements, including mixed uranium–plutonium oxide fuel for fast-neutron reactors; creation of low waste-production technologies of SNF processing and RAW disposal; and the analysis of fundamental features of the behavior and speciation of radionuclides in environmental objects for the development of efficient methods of radioecological monitoring and remediation of radionuclide-contaminated areas.  相似文献   

11.
Fossil energy consumption is one of the main reasons for the deterioration of environmental pollution and decline in public health. This paper tests for the long-run and short-run relationship among energy consumption, environment pollution and public health using the autoregressive-distributed lag approach in China for the period 1985–2014. The study used energy consumption variables (i.e., the proportion of coal consumption, that of oil and clean energy, abbreviated as PCC, POIL and PCE, respectively), environmental pollution ones (i.e., SO2 emissions, abbreviated SO2, soot and dust emissions,), two health proxies (i.e., the proportion of cardiovascular and respiratory diseases mortality, abbreviated as PCD and PRD, respectively). These variables were selected due to vital importance in China. The overall results indicate that there was co-integration relationship under the study with statistically significantly positive relationship between environmental pollution and energy consumption, public health and environmental pollution in the short and long run. Comparing the long-run and short-run coefficients of energy use variable with respect to SO2 and soot indicates that the long-run coefficients are the same as the short-run. The long-run coefficients of soot and dust emissions with respect to PCD and PRD, respectively, are higher than the short-run coefficients. This implies that environment pollution level is found to worsen with respect to fossil energy use presently and over time, while public health level descending with reference to soot and dust emission over time in China. The Granger causality results suggested a unidirectional Granger causality between energy use and environment pollution, environment pollution and public health. The results emphasized the importance of energy transformation and sustainable development policies that help to adjust the structure of energy consumption and to improve public health level.  相似文献   

12.
 This paper explores the implications of a misspecification of the production function on the use of factor inputs in the context of the adoption of an alternative production practice (a technological innovation) designed to mitigate the impact of agricultural production on human health and the environment. It is demonstrated that if the level of the use of some inputs is considered rather than their consumptive use (i.e., the actual amount used by a plant), the productivity of the input is inaccurately measured. It is also demonstrated that an aggregate production function approach can lead to overestimation of the value of the marginal product of an input due to the frequently implicit assumptions that the output supply, output demand, and fertilizer demand are infinitely price elastic. The implications of the results are important for determining the optimal use of inputs such as fertilizer and pesticides which have known adverse impacts on the environment and human health. Received: 22 November 1996 · Accepted: 4 May 1998  相似文献   

13.
14.
In China, coal mining wastes have traditionally been dumped in cone-shaped heaps that have the potential to pollute air, soil and water environments and landscapes through dust generation, leachate production, self-ignition and as a consequence of an absence of vegetation cover. Since 1980s, the disposal technique for coal mining wastes has been changing and in many instances the wastes are now transported directly to subsided land as a fill to enable the reuse of that land. Thus, today, both coal mining waste dumps from the past and filled subsided lands are in existence. However, the comparative impacts of these different disposal techniques on the environment and farmland productivity have not been studied in detail. Using Dongtan (DT), Nantun (NT) and Xinglongzhuang (XLZ) coal mines as examples, the components of coal mining wastes and their potential pollution contribution to soil, surface water and ground water are tested in-situ. The results show that contaminants are released after self-ignition and weathering of coal mining wastes, but they are not above the allowable environmental standards. However, despite these findings, more and closer attention needs to be paid to the mobility, transportation and accumulation of these contaminants in the environment over time.  相似文献   

15.
In this paper, the relationship between sulfate reduction potential and mercury methylation potential was studied in the Aha, Baihua and Hongfeng reservoirs from Guiyang City. The methylmercury (MeHg) concentrations of lake water in the Aha Reservoir were greatly elevated as compared to those of the Hongfeng and Baihua reservoirs, which was correlated with its distinctly high SRB abundance, SO42-, and S2- concentrations. Among the three reservoirs, however, the highest MeHg was observed in in the top several centimenters of pore water profile in the Hongfeng Reservoir where the lowest S2- in pore water occurred. The distributions of MeHg in lake water and pore water showed the highest methylation potential occurred at water-sediment surface for the Aha Reservoir and the in the top several centimenters of sediments for the Hongfeng Reservoir. It is guessed that the highest mercury methylation only occurs at the sites with certain sulfide concentrations.  相似文献   

16.
Cathodic protection using Al sacrificial anodes is a method of corrosion control that is often applied to submerged metallic structures. This technique leads to the progressive dissolution of the sacrificial anode and the metal(s) constituting the anode are inevitably released into the surrounding aquatic environment with potentially detrimental effects. The chemistry of sediments and waters from a French harbour where Al sacrificial anodes are deployed is examined in this study. In order to assess the potential influence of Al dissolution from the anode on the aquatic environment, total Al concentrations in water and sediment were determined and corresponding Al enrichment factors were calculated. Single and sequential extractions were also undertaken in order to evaluate the mobility of Al in the sediments. Results showed that whilst anodic dissolution does not significantly increase the concentration of Al in the water, both enrichment and an increase in the mobility of Al were evident in sediments sampled from the vicinity of the sacrificial anodes.  相似文献   

17.
18.
The university and the city   总被引:2,自引:0,他引:2  
Peter Hall 《GeoJournal》1997,41(4):301-309
Universities were originally urban institutions with a vocational mission, though later some of them lost these categories. The outstanding cases of university-industrial synergy are all American: Highway 128 around Boston, Silicon Valley in the San Francisco bay Area, and Los Angeles Aerospace Alley. They display common features, notably their dependence on defence contracts during the Cold war, but there are differences in the subsequent history. Europe and Japan provide more negative examples: the English M4 corridor west of London, the French Cité Scientifique Ile-de-France Sud and the Japanese science town of Tsukuba have all been less successful than their American counterparts, though Cambridge seems to have been an exception; interestingly, its origins were different.  相似文献   

19.
海绵城市建设是近年来城市规划和雨洪管理的重要方向。针对不同的地质环境条件特征,海绵城市建设的适宜性和措施建议各不相同。本文通过对郑州市白沙和高新两个典型地貌单元的海绵城市建设示范区进行研究,在查明区域地质环境条件的基础上,运用层次分析法对两个示范区的天然地质海绵体的适宜性进行评价。评价指标选取地表海绵体中的土地利用现状、地表岩性、地形坡度、土壤环境质量,地下海绵体中的岩性结构组合、厚度。评价结果显示白沙示范区适宜性整体优于高新示范区一个级别。白沙示范区浅层地下水埋深较浅,地层渗透性强,若加大开采力度,其海绵城市建设的蓄水能力会大大增强,海绵城市建设的适宜性也会随之提升;高新示范区虽水位埋藏深,但地层渗透性差,海绵城市建设潜力相对较小。针对不同的天然海绵体条件特征,应辅以相应的LID设施建议。  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号