A GIS based assessment of potential for windfarms in India

The Wind Energy Potential for India has been assessed, assuming as if the whole of the country (apart from the urban and the Himalayan areas) is covered with windfarms, by an innovative approach using GIS platform, wind speed measurements under government’s program and the NCEP/NCAR Reanalysis data.¹ The methodology involves setting up a grid of 1 sqkm resolution over areas other than urban settlements and Himalayan regions, computation of wind speeds at boundary layer level through vertical extrapolation of known or measured mean annual wind speed and interpolation of the extrapolated wind speeds to arrive at a mean annual wind field at boundary layer level and then computation of wind speed at the hub-height of the wind turbine. Power output from a standard wind turbine is computed and only areas showing a Plant Load Factor (PLF) higher than 15% are considered in the potential assessment. The results of this exercise indicate the potential for windfarms in India to be significantly higher than what was assumed earlier. The analysis and its revalidation using data measured at varying heights in different parts of the country establishe this approach as useful and perhaps a powerful tool to undertake wind resource potential assessments. This analysis and the results are discussed in the backdrop of the general energy scenario in India and earlier assessments of wind potential in the country.     

Performance analysis of artificial bee colony (ABC) algorithm in optimizing release policy of Aswan High Dam

The paper presents a study on developing an effective reservoir operation policy by using artificial bee colony (ABC) algorithm. The decision maker of a reservoir system always needs a guideline to operate the reservoir in an optimal way. Such guidelines named ‘release curves’ have developed for high-, medium-, and low-inflow category that can answer how much water needs to be released for a month by observing the reservoir level (storage condition). The Aswan High Dam of Egypt has been considered for the case study. For comparing the model efficiency, another heuristic approach—genetic algorithm (GA)—has been used. So far, GA is well established and most popular in reservoir release optimization. Historical inflow data for 18 years have been used for simulation purpose, and the general system performance-measuring indices (such as reliability, resiliency, and vulnerability) have been measured. The application procedure and problem formulation of ABC are very simple and can be used in optimizing reservoir system. After using the actual historical inflow, the release policy succeeded in meeting demand for about 98 % of the total time period. According to the simulation results, ABC algorithm showed better performance than the GA approach in reservoir release optimization.     

Assessment of hydraulic conductivity in the multi-layered aquifer system of the Bengal Basin,Bangladesh, by performing slug tests

Bulletin of Engineering Geology and the Environment - Various studies have described upon importance of the performance of multilevel slug tests to assess hydraulic conductivity of aquifer...     

Photocatalysis of xenobiotic organic compounds in greywater using zinc oxide nanoparticles: a critical review

The direct discharge of raw bathroom greywater has increased the concentrations of various pollutants in the water bodies. Typically, greywater contains large quantities of xenobiotic organic compounds (XOCs) owing to an increase in consumption of personal care and bath products. Therefore, it urges for a suitable technology to eliminate these compounds from contaminated waters. Photocatalytic degradation using Zinc Oxide nanoparticles (ZnO NPs) has the potentiality to eliminate various XOCs. However, ZnO NPs have high tendency to aggregate, which may lower the photocatalytic degradation rate. Therefore, there is an urgency to modify ZnO NPs to overcome the limitation. The present review was conducted to determine a suitable method for the modification ZnO NPs. Besides, the potential of the modified ZnO NPs in degrading XOCs in greywater as a photocatalyst was also discussed.     

Nanoforests composed of ZnO/C core–shell hexagonal nanosheets: fabrication and growth in a sealed thermolysis reactor and optical properties

An efficient method was developed for fabricating a highly porous nanoforest structure composed of ZnO/C core–shell hexagonal nanosheets (HNSs). Compact thermolysis of zinc acetate dihydrate in a sealed bath reactor at 400 °C over 20 h yielded the nanoforest structures. A carbon shell layer coating was applied in situ during the growth of the ZnO nanosheet core. The structures, morphologies, growth processes, compositions, and binding characteristics of the ZnO/C core–shell HNS nanoforests were analyzed using multi-purpose high-performance X-ray diffraction (XRD), scanning electron microscopy, energy-dispersive X-ray spectroscopy, Raman spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy (XPS) techniques. XRD and XPS results suggest the existence of oxygen vacancy defects in the core surface of ZnO/C core–shell. The ZnO/C core–shell HNS nanoforests exhibited strong absorption features from the visible to the near-IR region (400–1670 nm), and the nanoforest films showed high electrical conductivity.     

Variation in arsenic speciation and concentration in paddy rice related to dietary exposure

Ingestion of drinking water is not the only elevated source of arsenic to the diet in the Bengal Delta. Even at background levels, the arsenic in rice contributes considerably to arsenic ingestion in subsistence rice diets. We set out to survey As speciation in different rice varieties from different parts of the globe to understand the contribution of rice to arsenic exposure. Pot experiments were utilized to ascertain whether growing rice on As contaminated soil affected speciation and whether genetic variation accounted for uptake and speciation. USA long grain rice had the highest mean arsenic level in the grain at 0.26 microg As g(-1) (n = 7), and the highest grain arsenic value of the survey at 0.40 microg As g(-1). The mean arsenic level of Bangladeshi rice was 0.13 microg As g(-1) (n = 15). The main As species detected in the rice extract were AsIII, DMAV, and AsV. In European, Bangladeshi, and Indian rice 64 +/- 1% (n = 7), 80 +/- 3% (n = 11), and 81 +/- 4% (n = 15), respectively, of the recovered arsenic was found to be inorganic. In contrast, DMAV was the predominant species in rice from the USA, with only 42 +/- 5% (n = 12) of the arsenic being inorganic. Pot experiments show that the proportions of DMAV in the grain are significantly dependent on rice cultivar (p = 0.026) and that plant nutrient status is effected by arsenic exposure.     

IN‐RESERVOIR FRACTIONATION AND THE ACCUMULATION OF OIL AND CONDENSATES IN THE SURMA BASIN,NE BANGLADESH

Petroleum in the Surma basin, NE Bangladesh (part of the Bengal Basin) ranges from waxy crude oils to condensates. The origin and source rocks of these hydrocarbons were investigated based on the distributions of saturated and aromatic hydrocarbons in 20 oil samples from seven oil and gas fields. The relative compositions of pristane, phytane and adjacent n‐alkanes suggest that the source rock was deposited in a non‐marine setting. The abundance and similar distribution of biphenyls, cadalene and bicadinanes in most of the crude oils and condensates indicates a significant supply of higher‐plant derived organic matter to the source rocks. Maturity levels of the crude oils and condensates from the Surma basin correspond to calculated vitrinite reflectance (R_c) values of 1.0–1.3%, indicating hydrocarbon expulsion from the source rock at a comparatively high maturity level. The R_c values of oils from the Titas field in the southern margin of the Surma basin are relatively low (0.8–1.0%). Some oils were severely biodegraded. The similar distribution of diamondoid hydrocarbons in both biodegraded and non‐biodegraded oils indicated similar types of source rocks and similar maturity levels to those of oils from the Surma basin. The Oligocene Jenam Shale and/or underlying non‐marine deposits located at greater depths may be potential source rocks. The diversity of the petroleum in the Surma basin was likely due to evaporative fractionation, resulting in residual waxy oils and lighter condensates which subsequently underwent tertiary migration and re‐accumulation. Evaporative fractionation due to modification of the reservoir structure occurred during and after the Pliocene, when large‐scale tectonic deformation occurred in and around the Bengal Basin.