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1.
In recent years, bulk carriers have been identified with high risks of catastrophic structural failure and foundering, and with heavy loss of human life. This study, based upon Lloyd's of London casualty records, identified four risk factors that had significant, independent effect upon the likelihood of a bulk carrier foundering. The risk of foundering increased with the age of the ship, and was related to the ship's flag of registration. Most importantly, however, increased risks were found for heavy cargoes of iron ore and scrap steel or iron, and for trading routes to the Far East and from Europe to North America. Additional safety measures, in particular regarding ship design and high-risk trades, may well be necessary to reduce the high casualty rates. 相似文献
2.
A. B. Yavuz 《Environmental Geology》2006,51(2):211-227
?zmir is the third largest city in Turkey and has being the centre of art, culture, tourism and trade activities throughout the 5,000 years of its history. Natural stones brought from different parts of the world have been widely used for construction of the prestigious buildings, monuments and roads etc., in the past in the city. Renovation of the street pavements and public gathering areas in the city centre has been undertaken by the Metropolitan Municipality in 2000 and continued through the year of 2001. These renovation activities have mainly been carried out in the streets running parallel to the sea shore. Volcanic rocks brought from the Central Anatolia Ankara-Gölba?? (andesites) and Kayseri-?ncesu (tuffs) have been used in the renovation works. These rocks have shown extensive deteriorations within 4 years of their usage between 2001 and 2005 under the influence of different environmental factors. In this study, the deteriorations developed in the recently placed volcanic rocks used as kerb and pavement stones in the city centre of ?zmir in the light of their mineralogical, chemical, physical and mechanical properties, used locations and the environmental factors are presented. 相似文献
3.
矢量数字地图数据质量的综合评估 总被引:1,自引:0,他引:1
研究和确定了矢量数字地图数据的质量评估因子和评估标准,介绍了利用模糊综合评估方法进行质量评估的过程和做法,并给出了实例. 相似文献
4.
High-frequency (≥2 Hz) Rayleigh wave phase velocities can be inverted to shear (S)-wave velocities for a layered earth model up to 30 m below the ground surface in many settings. Given S-wave velocity (VS), compressional (P)-wave velocity (VP), and Rayleigh wave phase velocities, it is feasible to solve for P-wave quality factor QP and S-wave quality factor QS in a layered earth model by inverting Rayleigh wave attenuation coefficients. Model results demonstrate the plausibility of inverting QS from Rayleigh wave attenuation coefficients. Contributions to the Rayleigh wave attenuation coefficients from QP cannot be ignored when Vs/VP reaches 0.45, which is not uncommon in near-surface settings. It is possible to invert QP from Rayleigh wave attenuation coefficients in some geological setting, a concept that differs from the common perception that Rayleigh wave attenuation coefficients are always far less sensitive to QP than to QS. Sixty-channel surface wave data were acquired in an Arizona desert. For a 10-layer model with a thickness of over 20 m, the data were first inverted to obtain S-wave velocities by the multichannel analysis of surface waves (MASW) method and then quality factors were determined by inverting attenuation coefficients. 相似文献
5.
根据地震资料,对东南沿海地震区地震活动特下及未来趋势进行了初步分析与研究,结果表明:(1)从地震活动轮回分析,东南沿海地震区从1959年开始的第五个轮回中的地震活动时段,估计将延续到2031年前后结束,而后转入本轮回的平静时段;(2)2000年以前,研究区有可能发生1次Ms≥6.0地震,到2005到则最多发生2次;(3)东南沿海地震区下一次发生Ms≥6.0地震的地区可能在河源-邵武地震带上,尤其可 相似文献
6.
环境问题已成为全世界共同关心的问题。地质环境是影响人类生存的重要因素。本文述及了因自然地质因素引起的地震灾害、火山灾害、滑坡灾害等,以及因人为地质因素引发的水污染灾害、水库失事灾害、水土流失、沙漠扩大灾害等诸方面内容,指出在今后应重视对地质灾害的监测和预防。 相似文献
7.
地下水中氟形成的控制因素及其分布规律 总被引:11,自引:0,他引:11
本文研究了地下水中氟元素形成的主要控制因素及其分布规律。结果表明,地下水氟的形成与断裂构造,地下水温度、气候条件、含水介质及其上覆土层中的氟含量,地下水的酸碱度与径流条件有密切的关系。深成断裂脉状地下水和萤石矿区的地下水氟含量高,不有作为生活饮用水源; 而浅层的地下水氟含量较低,大多数仍作为生活饮用水源。 相似文献
8.
Effects of geology and human activity on the dynamics of salt-water intrusion in three coastal aquifers in southern Spain 总被引:4,自引:0,他引:4
Mathematical modelling of salt-water intrusion processes in three aquifers on the southern coast of Spain (Río Verde, Río
Vélez and Castell de Ferro) reveals that, although all three systems are subject to the same climate and seasonal over-exploitation,
geological and human factors have very different effects on the dynamics of contamination. In the Río Verde aquifer, the most
important influence is the high volume of extractions occurring during the dry season; in Río Vélez, the intrusion is strongly
controlled by infiltration of water from the river to the aquifer, and, in the Castell de Ferro system, an intensely karstified
carbonate massif lying in contact with both the sea water and the detrital aquifer represents the main entrance point for
influx of sea water and subsequent washing of the aquifer. We have undertaken a mathematical simulation of various possible
measures to counteract intrusion, according to the specific characteristics of the process in each aquifer. These measures
include artificial recharge, use of natural recharge from the river as a hydraulic barrier, and the construction of a low-permeability
barrier.
Received: 5 December 1995 · Accepted: 12 April 1996 相似文献
10.
从铬的地球化学性状、铬铁矿的形成过程, Al3+, Fe3+对 Cr3+的制约机制及矿石矿物共生组合特征讨论了控制铬铁矿矿石质量的因素,这一研究对评价矿石质量有重要意义。 相似文献