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71.
Aziz Ghaderpour Khairul Nazrin Mohd Nasori Li Lee Chew Ving Ching Chong Kwai Lin Thong Lay Ching Chai 《Marine pollution bulletin》2014
The deltaic estuarine system of the Matang Mangrove Forest Reserve of Malaysia is a site where several human settlements and brackish water aquaculture have been established. Here, we evaluated the level of fecal indicator bacteria (FIB) and the presence of potentially pathogenic bacteria in the surface water and sediments. Higher levels of FIB were detected at downstream sampling sites from the fishing village, indicating it as a possible source of anthropogenic pollution to the estuary. Enterococci levels in the estuarine sediments were higher than in the surface water, while total coliforms and E. coli in the estuarine sediments were not detected in all samples. Also, various types of potentially pathogenic bacteria, including Klebsiella pneumoniae, Serratia marcescens and Enterobacter cloacae were isolated. The results indicate that the Matang estuarine system is contaminated with various types of potential human bacterial pathogens which might pose a health risk to the public. 相似文献
72.
An atmospheric electric field exerts a torque on both column and plate ice crystals. Columns tend to align along the direction of the field. One diameter of plate crystals also aligns parallel to a field, while a non-uniform diverging field leads to further orientation and proscribes a secondary orientation along the direction of least divergence. A laboratory investigation treats the electrical orientation of thin plate ice crystals in a non-uniform field as a two-step process. In the model, the average field provides the primary torque and aligns one diameter of the plate crystal while simultaneously a spatially varying component of the field aligns the perpendicular diameter. The first element of the process, the primary torque, has been investigated previously. The complete reorientation, caused by a secondary torque, is investigated herein. Experimentally a stronger field with sufficient non-uniformity is required to demonstrate the secondary torque. The realignment caused by this torque depends also on the strength of the aerodynamic torques on the falling ice crystals. Experiments in a laboratory cold chamber with small thin plate crystals in an electric field provided by a charged rod demonstrate crystal reorientation by changing the reflections of a beam of white light. A model incorporating electrical torques is applied to the laboratory observation and used to investigate the possibility of the effects occurring in the atmosphere. Fields near lightning strokes, which are strong but of short duration, may reorient small crystals. Larger crystal aggregates like planar snowflakes are governed by the same electrical torques. It is suggested that the secondary torque realignment might be observable for aggregates large enough to be detected by radar in cases pertaining to weaker but longer duration fields associated with cloud electrification. A simplification of the model is used to investigate electrically caused crystal motion and linear aggregation, with applications to the atmosphere and to lightning initiation. 相似文献
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Space technologies, such as kinematic Global Positioning System (GPS), often combined with an inertial navigation system (INS), provide an efficient direct georeferencing tool for remote sensing and aerial surveying. Practically, these systems are now able to deliver high-precision orientation data for spatial data acquisition platforms in a timely manner, at relatively low cost, as compared to traditional methods. The Airborne Integrated Mapping System (AIMS (TM)), developed at The Ohio State University Center for Mapping, integrates high-resolution digital imagery, differential GPS/INS, and precise timing for high-quality data acquisition supporting large-scale mapping and other precise positioning applications. In this article, the AIMS (TM) system hardware/software configuration, its current operational capabilities, and the test results of airborne mapping of the coastal zone are presented. 相似文献
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A new rock mass classification for Coal Measures Rocks 总被引:2,自引:0,他引:2
Ergül Ya
ar 《Engineering Geology》2001,62(4):293-300
This paper examines a new rock mass classification system (RMCR) for Coal Measures Rocks which is based on extensive laboratory testing results. The new system has been developed using 12 parameters which consist of mineral content index, uniaxial compressive strength, uniaxial tensile strength, Young's modulus of elasticity, shear strength, cohesion of rocks, angle of internal friction, point load index, cone indenter index, Cerchar index, Shore schleroscope hardness and specific energy index. The RMCR value was obtained by a number of laboratory and in situ testing results which were obtained from the coal site. The objective of the RMCR is to estimate the rock mass properties for engineering purposes. 相似文献
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磁通门磁变仪实际工作在弱铁磁环境。本文分析了弱铁磁环境等对磁通门磁定仪定向的影响,得出了弱铁磁影响等环境中磁通门磁变仪准确定向的方法。 相似文献
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