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101.
A discussion is presented here to the work of Wang and Qiu including some notes about the analysis and the correlations of the results. First, we show that there is no clear relationship between the critical hydraulic gradient and the uniformity coefficient. Also we show that the internal erosion mechanism of soils with bimodal structure is different from that for soils with no bimodal structure. Finally, we emphasis that the anisotropy in the hydraulic conductivity is not related to the uneven compaction only but also to the particle arrangements and connectivity between pores. 相似文献
102.
Divisional morphogenesis in the marine ciliate Anteholosticha manca (Kahl, 1932) Berger, 2003 (Ciliophora: Urostylida) 总被引：1，自引：1，他引：0
LI Liqiong HU Xiaozhong WARREN Alan AL-RASHEID Khaled A S AL-FARRAJ Saleh A SHAO Chen SONG Weibo 《海洋学报(英文版)》2008,27(2):157-163
The cortical development and macronuclear evolution of the marine hypotrichous ciliate Anteholosticha manca, collected from the coastal waters near Qingdao, China, were investigated using the protargol impregnation method. The morphogenesis of A. manca is generally typical for the genus, and can be characterized as the following features ： （ 1 ） in the proter, a new oral primordium is formed on the bottom （beneath the pellicle） of the buccal cavity, disorganization of the parental undulating membranes do not contribute to the formation of this primordium ; （2） FVT-cirral anlagen in both dividers develop independently, and very likely only a few midventral cirri join in the formation of these primordia; （ 3 ） both marginal row and dorsal kinety anlagen develop intrakinetally within the parental structure; （4） at the middle stage, macronuclear segments fuse together to form a single mass as observed in most of its related forms. 相似文献
103.
One hundred and thirty nine samples have been studied from the Late Campanian–Early Maastrichtian of three deep wells drilled in Jiza’-Qamar Basin, Eastern Yemen to determine the calcareous nannofossil zones and the age of the sediments. Forty-seven calcareous nannofossil species were identified and four biozones were determined in the present study (CC21–CC24). These biozones are assigned to the Late Campanian–Early Maastrichtian ages. Most of the studied species in this work refer to tropical–subtropical environment. The Campanian–Maastrichtian Boundary was determined in Al-Fatk well based on the last occurrence of Eiffelithus eximus and the last occurrences of Uniplanarius sissinghii and Uniplanarius trifidus. 相似文献
104.
Khaled K. Al-Taha Richard T. Snodgrass Michael D. Soo 《International journal of geographical information science》2013,27(1):95-103
Abstract There now exist several microcomputer processing systems which incorporate algorithms and display techniques appropriate for the class of objects known as images. Zooming, histogram equalization, contrast stretching, ratioing, edge enhancement, and filtering are common options used in these systems. In the present discussion a system is proposed for the equivalent processing of general resolution elements (resells), instead of the homogeneous picture elements (pixels) which are found in image processing systems. The resel processing system requires a new, generalized, repertoire of processing algorithms and a high resolution display. A summary is provided of the facilities and procedures required, a computational metaphor using computer spreadsheets is described, and the applicability to censels (census data elements) and to medical data is suggested. 相似文献
105.
Magmatism at continental passive margins inferred from Ambient‐Noise Phase‐velocity in the Gulf of Aden 
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下载免费PDF全文 Félicie Korostelev Sylvie Leroy Derek Keir Cornelis Weemstra Lapo Boschi Irene Molinari Abdulhakim Ahmed Graham W. Stuart Frédérique Rolandone Khaled Khanbari Ali Al‐Lazki 《地学学报》2016,28(1):19-26
Non‐volcanic continental passive margins have traditionally been considered to be tectonically and magmatically inactive once continental breakup has occurred and seafloor spreading has commenced. We use ambient‐noise tomography to constrain Rayleigh‐wave phase‐velocity maps beneath the eastern Gulf of Aden (eastern Yemen and southern Oman). In the crust, we image low velocities beneath the Jiza‐Qamar (Yemen) and Ashawq‐Salalah (Oman) basins, likely caused by the presence of partial melt associated with magmatic plumbing systems beneath the rifted margin. Our results provide strong evidence that magma intrusion persists after breakup, modifying the composition and thermal structure of the continental margin. The coincidence between zones of crustal intrusion and steep gradients in lithospheric thinning, as well as with transform faults, suggests that magmatism post‐breakup may be driven by small‐scale convection and enhanced by edge‐driven flow at the juxtaposition of lithosphere of varying thickness and thermal age. 相似文献
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M. A. Khaled 《Astrophysics and Space Science》2014,350(2):607-614
The head-on collision of two ion acoustic solitary waves propagating in opposite directions in a weakly relativistic electron-positron-ion plasma composed of weakly relativistic warm ion fluid and nonextensive electrons, positrons is investigated. Using extended Poincaré-Lighthill-Kuo method, the Korteweg-de Vries equations and the analytical phase shifts after the head-on collision of two solitary waves are derived. The effects of the nonextensive parameter, positron-to-electron density ratio, ion-to-electron temperature ratio, electron-to-positron temperature ratio and relativistic factor on the phase shifts are studied. It is found that these parameters can significantly influence the phase shifts of solitary waves. 相似文献
109.
The best way of reducing roll motion is by increasing roll damping. Bilge keels are the most common devices for increasing roll damping. If more control is required, anti-roll tanks and fins are used. Tanks have the advantage of being able to function when the ship is not underway. Our objective is to develop design procedures for passive tanks for roll reduction in rough seas. This paper focuses on the design of passive U-tube tanks. The tank-liquid equation of motion is integrated simultaneously with the six-degree-of-freedom (6DOF) equations of the ship motion. The coupled set of equations is solved by using the Large Amplitude Motion Program ‘LAMP’, which is a three-dimensional time-domain simulation of the motion of ships in waves. The unstabilized and stabilized roll motions of a S60-70 ship with forward speed and beam waves have been analyzed. For high-amplitude waves, the unstabilized roll angle exhibits typical nonlinear phenomena: a shift in the resonance frequency, multi-valued responses, and jumps. The performance of a S60-70 ship with a passive tank is investigated in various sea states with different encounter wave directions. It is found that passive anti-roll tanks tuned in the linear or nonlinear ranges are very effective in reducing the roll motion in the nonlinear range. The effect of the tank damping, frequency, and mass on the tank performance is studied. Also, it is found that passive anti-roll tanks are very effective in reducing the roll motion for ships having a pitch frequency that is nearly twice the roll frequency in sea states 5 and 6. 相似文献
110.
This paper deals with the efficacy of creating artificial carbonate sand from crushed chalk to model the natural carbonate
sand. Direct drained shear using 100 mm shear box and compressibility tests using 150 mm Rowe cell have been performed on
artificial carbonate sand in order to determine the shear stress-strain and compressibility characteristics of the artificial
material. These are compared with data from natural carbonate sands given in the literature. The results obtained demonstrate
that shear stress-strain and compressibility characteristics of the artificial material closely mirror that of natural carbonate
soils. The artificial carbonate sand shows generally similar characteristics, which are in the range of the natural carbonate
material. 相似文献