20 research outputs found
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Genesis of silica-enriched agricultural pans in soils managed under wheat-fallow cropping systems
Molecular dynamics and density functional theory study on the corrosion inhibition of austenitic stainless steel in hydrochloric acid by two pyrimidine compounds
Energy overview for the sultanate of oman
Since 1967, exporting crude oil has been the leading hard-currency earner for Oman: ~9x105 barrels of crude oil per day being extracted in 1997. The total remaining oil reserves, which can be harnessed economically now, amount to approximately 5.2x109 barrels, but this commercially-available resource is expected to be depleted completely by the year 2015. The second most important source of energy in the country is natural gas: present economically-harnessable reserves are approximately 724x109 Nm3. In 1994, the amount extracted was merely 2.4x109 Nm3. This resource is expected to be exhausted by the year 2064. From 1990 to 1995, the Government-run electricity-generation power-capability rose from 1277 to 1642 MW: the peak demand has grown simultaneously by 59%. The total-power generation in 1995 was 6500 GWh, while the annual consumption was 6173 GWh; the domestic sector accounting for approximately 60% of the total consumption. The rate of energy consumption pattern is seasonal in nature, with the mid-summer electric demand being nearly triple that of mid-winter. Private cars accounted for 54% of the total number of vehicles in Oman in 1994, and this number is rising rapidly. The associated freedom of choice to use the private car in order to satisfy the desires for increased mobility and privacy will not be sustainable in the long term.
Prospects for harnessing wind-power economically in the sultanate of Oman
Wind power as a source of harnessible energy is assessed. Average data over the 10 year period, 1985-1994, have been compiled for 12 different widely spaced locations in Oman. It is concluded that the three most promising sites for the economic harnessing of wind-power are Thumrait (latitude 17.67°N and altitude 466.86 m above sea level), Masirah (latitude 20.67°N and altitude 18.80 m above sea level) and Sur (latitude 22.54°N, and altitude 13.7 m above sea level). These locations are situated in the Southwest monsoon region of influence. The largest wind speeds occur during the summer from June to August. The highest (i.e. ~10 m s-1) long-term (i.e. over 10 years) monthly mean wind speed is that for Thumrait and ensues during the month of July.
Water table rise in arid urban area soils due to evaporation impedance and its mitigation by intelligently designed capillary chimney siphons
Waterlogging of urban area soil in a hyperarid climate, caused by impedance of evapotranspiration due to land cover by an impervious pavement, is studied by a multidisciplinary team of researchers (hydropedeologists, hydrogeologists, groundwater engineers, soil physicists and mathematical modelers). In this paper, a study unique for an arid/hyperarid MENA region has been conducted: from soil pedons’ data, a thin vadose zone superjacent to a shallow water table of a coastal aquifer in Oman is described with emphasis on soil profile morphology layering and determination of the van Genuchten hydraulic parameters, used in HYDRUS modeling of evaporation-driven saturated/unsaturated flows. On a large scale, for capillarity-free groundwater flow, the Dupuit–Forchheimer model is used and an analytical solution is obtained. Intensive evaporation from the water table to a bare unpaved soil surface is impeded by an impermeable surface strip (land pavement) with an ensued rise of the water table. Waterlogging is quantified by the “dry area,” Sd, under the strip. This integral is explicitly evaluated as a function of the model parameters: aquifer’s size and evaporation-normalized conductivity, the width of the strip, d, and its locus with respect to the shoreline, u1. Nontrivial extremes of Sd(d,u1) are found. Contrary to the surface pavement, intensification of evaporation by capillary siphons, i.e., structural heterogeneities of a porous massif, is proposed as an engineering mitigation of groundwater inundation. Composite porous media with siphons (small-size rectangular inclusions of a contrasting finer texture) are numerically tackled by MODFLOW and HYDRUS2D. A constant flux or a constant pressure head condition is imposed on the top of the flow domain. The water table is shown to drop and Sd to increase as a result of such “passive moisture pumping” from the aquifer. A potential model for 2D tension-saturated flow is used to solve a mixed boundary-value problem in a rectangular wick. Its flow rate is analytically evaluated as a function of evaporating width and the height of the “window” through which the aquifer feeds the wick. Conformal mapping of a rectangle in the physical domain onto a rectangle in the complex potential plane is realized via two reference planes and elliptic functions