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111.
Abdul Rani Abdullah Norhayati Mohd. Tahir Tong Soo Loong Tafazzal Mohd. Hoque Abdul Halim Sulaiman 《Marine pollution bulletin》1999,39(1-12):229-233
The Straits of Malacca is subjected to a great variety of environmental stresses due to its strategic location as a major international shipping lane and the concentration of agriculture, industry and urbanisation which predominate on the west coast of Peninsular Malaysia. This paper gives an overview of the study conducted in the Malacca Straits as part of the GEF/UNDP/IMO Regional Programme on the Prevention and Management of Marine Pollution in the East Asian Seas, in particular pertaining to the identification of land and sea-based sources of pollution in Malaysia which contributes to the pollution load in the Straits, as well as the assessment of the relative contribution of each source. 相似文献
112.
Globally, shrimp farming has been a significant agro-based economic activity since the early 1970s. Because it offered a huge immediate economic return, shrimp farming showed a booming expansion and soon became a multimillion dollar industry. However, it has been under extreme criticism because of its devastating ecological and socio-economic impacts. Because seed is the primary input, the impact from farming has started from the source of seed supply, so that not only are natural stocks of shrimp seeds now overexploited worldwide but seed collection activities also significantly reduce stocks of other living resources. Although hatcheries were developed as potential alternative and have replaced the natural seed source to a great extent, large-scale hatchery productions provide a potential source of coastal pollution. However, this area is still poorly studied. The present paper provides a review of the environmental impacts of the wild shrimp seed fishery as well as the possibility of environmental degradation from artificial shrimp seed production in hatcheries. 相似文献
113.
A simple relationship has been developed between the wall coordinate y+ and Kolmogorov's length scale using direct numerical simulation (DNS) data for a steady boundary layer. This relationship is then utilized to modify two popular versions of low Reynolds number k–ε model. The modified models are used to analyse a transitional oscillatory boundary layer. A detailed comparison has been made by virtue of velocity profile, turbulent kinetic energy, Reynolds stress and wall shear stress with the available DNS data. It is observed that the low Reynolds number models used in the present study can predict the boundary layer properties in an excellent manner. 相似文献
114.
近年来示踪技术作为研究水动力和泥沙冲淤规律的工具得到越来越广泛的应用。示踪技术比传统的水文观测方法方便、准确。传统研究方法往往只能进行定点或走航采样监测,而示踪技术则能准确判定某一区域泥沙或水流的具体运动过程和最终运动结果,甚至给出定量的结论,从而为数学模型参数的确定提供有效的依据。Pujol使用3H监测西班牙Ebro河的横向扩散速率[1],Albert在Ebo河用同样的方法研究水 相似文献
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117.
H. Abdul Aziz M. Böhme A. Rocholl A. Zwing J. Prieto J. R. Wijbrans K. Heissig V. Bachtadse 《International Journal of Earth Sciences》2008,97(1):115-134
A detailed integrated stratigraphic study was carried out on middle Miocene fluvial successions of the Upper Freshwater Molasse
(OSM) from the North Alpine Foreland Basin, in eastern Bavaria, Germany. The biostratigraphic investigations yielded six new
localities thereby refining the OSM biostratigraphy for units C to E (sensu; Heissig, Actes du Congres BiochroM’97. Mem Trav
EPHE, Inst Montpellier 21, 1997) and further improving biostratigraphic correlations between the different sections throughout eastern Bavaria. Radioisotopic
ages of 14.55 ± 0.19 and 14.88 ± 0.11 Ma have been obtained for glass shards from the main bentonite horizon and the Ries
impactite: two important stratigraphic marker beds used for confirming our magnetostratigraphic calibration to the Astronomical
Tuned Neogene Time Scale (ATNTS04; Lourens et al. in Geologic Time Scale 2004, Cambridge University Press, 2004). Paleomagnetic analysis was performed using alternating field (AF) and thermal (TH) demagnetization methods. The AF method
revealed both normal and reverse polarities but proofs to yield unreliable ChRM directions for the Puttenhausen section. Using
the biostratigraphic information and radioisotopic ages, the magnetostratigraphic records of the different sections are tentatively
correlated to the Astronomical Tuned Neogene Time Scale (ATNTS04; Lourens et al. in Geologic Time Scale 2004, Cambridge University
Press, 2004). This correlation implies that the main bentonite horizon coincides to chron C5ADn, which is corroborated by its radioisotopic
age of 14.55 Ma, whereas the new fossil locality Furth 460, belonging to OSM unit E, probably correlates to chron C5Bn.1r.
The latter correlation agrees well with the Swiss Molasse locality Frohberg. Correlations of the older sections are not straightforward.
The Brock horizon, which comprises limestone ejecta from the Ries impact, possibly correlates to C5ADr (14.581–14.784 Ma),
implying that, although within error, the radioisotopic age of 14.88 ± 0.11 Ma is somewhat too old. The fossil localities
in Puttenhausen, belonging to the older part of OSM unit C, probably coincide with chron C5Cn.2n or older, which is older
than the correlations established for the Swiss Molasse.
Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users. 相似文献
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119.
Satoru Takanashi Yoshiko Kosugi Shinjiro Ohkubo Naoko Matsuo Makoto Tani Abdul Rahim Nik 《水文研究》2010,24(4):472-480
We measured the fluxes of sensible and latent heat between a low‐land dipterocarp forest in Peninsular Malaysia and the atmosphere. No clear seasonal or interannual changes in latent heat flux were found from 2003 to 2005, while sensible heat flux sometimes fluctuated depending on the fluctuation of incoming radiation between wet and dry seasons. The evapotranspiration rates averaged for the period between 2003 and 2005 were 2·77 and 3·61 mm day?1 using eddy covariance data without and with an energy balance correction, respectively. Average precipitation was 4·74 mm day?1. Midday surface conductance decreased with an increasing atmospheric water vapour pressure deficit and thus restricted the excess water loss on sunny days in the dry season. However, the relationship between the surface conductance and vapour pressure deficit did not significantly decline with an increase in volumetric soil water content even during a period of extremely low rainfall. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
120.
One of the most important considerations in designing cut slopes in sub-horizontal, inter-layered, sedimentary rocks subject to differential weathering is predicting the total depth of undercutting. Undercutting-induced rockfalls are a major problem for many roadways in Ohio. The total depth of undercutting was measured for 59 profiles from 18 cut slope sites in Ohio with references to cut faces of hard rock units containing pre-split blast-hole traces. The presence of blast hole traces ensured that the rock face represented the slope surface that was cut during construction. Additionally, initial design plans were used for reference. Step-wise regression was used to determine the geological, geotechnical, and geometrical factors that have the highest influence on the total depth of undercutting. Selected independent factors used in the regression analysis included the vertical distance of the undercut unit from the slope crest, the relative position of the undercut unit from the slope crest, the total thickness of the undercut unit, the spacing of orthogonal joints within the undercut unit, the slake durability index value of the undercutting unit, the initial slope angle, and the age of the road cut. Factors that showed the most significant correlation with the total depth of undercutting were found to be the vertical distance of the undercut unit from the slope crest, the relative position of the undercut unit from the slope crest, the total thickness of the undercut unit, joint spacing within the undercut unit, and the slake durability index of the undercutting unit. The regression analysis resulted in an R2 value of 0.61, with the depth of undercutting correlating most strongly with a closer relative position of the undercut unit to the slope crest above it and to a closer spacing of orthogonal joints within the undercut unit. These results can be attributed to the fact that more porous and fractured rock units closer to the slope crest intercept and transport greater amounts of infiltrating groundwater, producing greater depths of undercutting. Also, closely jointed rock units are more permeable, allowing more groundwater seepage, which also leads to greater undercutting. 相似文献