Criteria of Acceptance for Constant Rate of Strain Consolidation Test for Tropical Cohesive Soil     

Khairul Anuar Kassim  Ahmad Safuan A. Rashid  Ahmad Beng Hong Kueh  Chong Siaw Yah  Lam Chee Siang 《Geotechnical and Geological Engineering》2016,34(4):931-947

In this study, the rapid consolidation equipment (RACE) was developed as an alternative device to the conventional consolidation test using Oedometer, consuming merely a few hours for the whole precedure to determine the consolidation characteristics of cohesive soil. RACE operates based on the constant rate of strain (CRS) consolidation theory, which is a continuous loading method of testing, requiring a good estimation of the loading rate such that it is ideal for the achievement of steady state condition during testing. The steady state condition is achieved when the c _v values from drained and undrained face of CRS converged with the c_v from Oedometer test. A slightly modification has been made on the normal constant rate of strain (CRS) test by proposing a direct back pressure system to the specimen using a tube to saturate the soil sample. This research has produced a set of criteria for determining the suitable rate for the rapid consolidation test based on the ratio of normalized strain rate, β, and proposed a new coefficient in terms of a ratio of β to clay fraction (CF), as a part of new criteria for testing a fine soil. Four types of sample were tested with different rates of strain using the RACE and their results were compared with those conducted using the Oedometer on the same soil type, from which fairly good agreements were evident in many specimens. It was found from the study that the minimum value of normalized strain rate, β, for the CRS test is 0.005 and for the u _a /σ _v ratio is suggested as 0.01. Also, the maximum β/CF for soils with clay friction lower and higher than 50 % are 0.008 and 0.001, respectively. The minimum β/CF value for both conditions is 0.0001.  相似文献   

Statistical downscaling of rainfall: a non-stationary and multi-resolution approach     

Md. Mamunur Rashid  Simon Beecham  Rezaul Kabir Chowdhury 《Theoretical and Applied Climatology》2016,124(3-4):919-933

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Assessing changes in the above ground biomass and carbon stocks of Lidder valley,Kashmir Himalaya,India   总被引：1，自引：0，他引：1  

Irfan Rashid  Mudasir Ahmad Bhat  Shakil Ahmad Romshoo 《国际地球制图》2017,32(7):717-734

The changes in the land use and land cover (LULC), above ground biomass (AGB) and the associated above ground carbon (AGC) stocks were assessed in Lidder Valley, Kashmir Himalaya using satellite data (1980–2013), allometric equations and phytosociological data. Change detection analysis of LULC, comprising of eight vegetation and five non-vegetation types, indicated that 6% (74.5 km²) of the dense evergreen forest has degraded. Degraded forest and settlement increased by 20 and 52.8 km², respectively. Normalized difference vegetation index was assessed and correlated with the field-based biomass estimates to arrive at best-fit models for remotely sensed AGB estimates for 2005 and 2013. Total loss of 1.018 Megatons of AGB and 0.5 Megatons of AGC was estimated from the area during 33-year period which would have an adverse effect on the carbon sequestration potential of the area which is already facing the brunt of climate change.  相似文献   

Potential economic benefits from sablefish farming in British Columbia     

Ussif Rashid Sumaila  John Volpe  Yajie Liu 《Marine Policy》2007

We present in this paper results of an analysis of the potential economic contribution of sablefish farming in British Columbia (BC). This is necessary because a BC sablefish hatchery has recently begun production of juvenile sablefish for grow-out in marine net pens. The production from this single hatchery is anticipated to effectively support sablefish production that will match the entire current BC sablefish capture fishery. Two key questions we address are, how will net benefits (added value) to BC from the sablefish sector be affected if (i) BC and the rest of the world engage in sablefish farming, and (ii) BC bans sablefish farming while the rest of the world does not. We find that at low BC aquaculture production levels, small economic gains are possible. However, gains quickly disappear as production increases towards anticipated levels. A sablefish-farming ban in BC could be beneficial to the province and Canada if BC wild sablefish landings command a price premium of at least 20–25%.  相似文献   

Farm income,inequality, and poverty among farm families of a flood-prone area in Bangladesh: climate change vulnerability assessment     

Alamgir  Md. Shah  Furuya  Jun  Kobayashi  Shintaro  Mostafiz  Rubaiya Binte  Ahmed  Md. Rashid 《GeoJournal》2021,86(6):2861-2885

GeoJournal - This paper examines the farm income differences, income inequality of farm households, parameters of income variability that ascertain vulnerability levels, and cost-income variability...  相似文献   

Comments on ‘Does the Agulhas Current amplify global temperatures during super‐interglacials?’     

H. Rashid  F. O. Otieno  M. K. Konfirst 《第四纪科学杂志》2011,26(8):866-869

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Unroofing history of a suture zone in the Himalaya of Pakistan by means of fission-track annealing ages     

Peter K. Zeitler  Rashid A.K. Tahirkheli  Charles W. Naeser  Noye M. Johnson 《Earth and Planetary Science Letters》1982,57(1):227-240

The uplift history of the Swat Valley and Hazara region of northwestern Pakistan has been established using 22 fission-track dates on apatite, zircon and sphene. A major fault, the Main Mantle Thrust (MMT) strikes east-west across the Swat Valley, separates regions of markedly differing fission-track age regimesm, and may be a suture zone separating an extinct island arc terrane on the north from the Indian plate to the south. Fission-track ages ranging from about 55 to 58 m.y. for sphene, 18 to 53 m.y. for zircon, and 9 to 17 m.y. for apatite were obtained from the region north of the MMT. To the south the fission-track age ranges are 20 to 25 m.y. for sphene, 17 to 26 m.y. for zircon, and 16 to 23 m.y. for apatite. Disparate zircon and sphene ages on each side of the MMT imply different cooling histories for each side of the fault prior to 15 m.y. Similar apatite ages on both sides of the fault imply similar cooling histories during the past 15 m.y. This may indicate that faulting ceased by 15 m.y. Mean uplift rates have been derived from the fission-track data using mainly the mineral-pair method. Uplift rates in the region north of the MMT increased from 0.07 to 0.20 mm/yr during the period 55 to 15 m.y. South of the fault, uplift rates averaged in excess of 0.70 mm/yr for the period 25 to 15 m.y. During the past 15 m.y. uplift across the MMT in the Swat Valley showsno discontinuities, ranging from 0.16 mm/yr in the south to 0.39 mm/yr in the north. A plausible interpretation for the fission-track uplift data has the MMT verging to the south with overthrusting taking place at a depth between 3.5 and 6.0 km, juxtaposing two terranes that were originally separated by a substantial, but unknown distance. In this model, regional uplift followed cessation of faulting just prior to 15 m.y.  相似文献   

The influence of a salt dome on the diagenesis of organic matter in the Jeanne d'Arc Subbasin of the northeast Grand Banks of Newfoundland     

M.A. Rashid 《Organic Geochemistry》1978,1(2):67-77

This study elucidates the geothermal influence of a salt dome on the diagenesis of organic matter present in sedimentary sequences directly overlying the salt strata. Despite similarities in geological setting, geochemical characteristics in sedimentary column and proximity of location (～3 km), the exploratory wells Adolphus 2-k-41 and D-50 drilled on the crest and flank of a salt dome respectively, show considerable differences in the quantitative and qualitative distribution of hydrocarbons. The well drilled on the crest of the salt dome tested oil of 31°APl gravity. The concentrations of gaseous (C₁-C₄) and heavy (C₁₅⁺) hydrocarbons of this well were several times higher than those found in the corresponding sequences of a flank well. The coloration studies of isolated kerogen and gas chromatographic investigations of hydrocarbons suggest that the organic matter present in Adolphus 2-k-41 has undergone a greater degree of thermal alteration than that of D-50. The heat radiating from the salt strata is believed to be responsible for the early diagenesis of the organic matter.  相似文献   

Geological environment of a methane-rich Recent sedimentary basin in the Gulf of St. Lawrence     

M.A. Rashid  G. Vilks  J.D. Leonard 《Chemical Geology》1975,15(2):83-96

Two sediment cores collected in Chaleur Trough, Gulf of St. Lawrence are compared in terms of organic geochemistry, sediment texture and foraminifera. One of the cores was collected from a depression and contained methane in the range of 5,970–14,230 ppm, in comparison to 42–106 ppm in the core of open environment. The sediments of the methanerich core are finer, higher in organic carbon, extractable organic matter, plant pigments and contained more diverse foraminiferal assemblages. The results of these geological investigations tend to suggest a relatively fast rate of sedimentation in the depression. This results in the preservation of organic compounds and development of anaerobic subsurface conditions, consequently giving rise to high concentrations of methane through fermentative processes. No other gaseous hydrocarbons were detected hence the possibility of seepage of petroleum gases appears to be remote.  相似文献   

Influence of marine organic compounds on the engineering properties of a remoulded sediment     

M.A. Rashid  J.D. Brown 《Engineering Geology》1975,9(2):141-154

Rashid, M.A. and Brown, J.D. 1975. Influence of marine organic compound on the engineering properties of a remoulded sediment. Eng. Geol., 9: 141–154The effect of low to moderate organic content on the engineering properties of a remoulded marine sediment was investigated by classificatin tests, undrained shear-strength tests, consolidation tests and triaxial compression tests. Sediment with a naturally occuring organic content of 2%, was treated to provide 0, 3, and 4% organic matter; first by reaction with hydrogen peroxide to remove the organic matter and then by addition of a naturally occuring humic compound in the latter two cases. In its natural state the sediment was classified as an organic sediment of low plsticity. Addition of the stated amounts of organic content did not result in the sediment being classified as organic; however, the remoulded undrained shear stregnth, the compressability, and the rheological behaivior of the sediment were significantly affected by ht evariations in the organic content. By contrast, the effects of these variations on the specific gravity, permeability, rate of consolidation and consolidated-undrained shear stregnth were not very marked.  相似文献