Analysis of Wind Farm Output: Estimation of Volatility Using High-Frequency Data

In the financial year 2011–2012, wind farms supplied 26 % of South Australia’s electricity demand according to the Australian Energy Market Operator’s report. This contribution has risen from zero in 2003. The operation of the electricity grid depends heavily on knowledge of the variability of supply. Wind farm output displays similar conditional volatility as financial market variables. In this paper, a new method of estimating wind farm output volatility on a 5-min time scale is developed through the use of higher-frequency wind farm output data. First, an autoregressive model for the high-frequency data is developed, and it is used to derive a volatility measure for 5-min data. The results are also true in certain general situations when the high-frequency data follow an autoregressive moving average process or exhibits long memory features. The methods described here are analogous to realised volatility measures used in financial series, except that wind farm output data are measured at uniform intervals, unlike random trading times for financial transactions.     

Anaerobic digestion of fruit and vegetable waste: a critical review of associated challenges

Environmental Science and Pollution Research - The depletion of fossil fuels coupled with stringent environmental laws has encouraged us to develop sustainable renewable energy. Due to its numerous...     

Distribution of detoxifying genes polymorphism in Maharastrian population of central India

The present study is aimed at evaluating the genotype frequency of detoxifying genes such as GSTM1, GSTT1 and NQO1 in Maharastrian population of central India. The study revealed about 64.6% of GSTM1-positive and 35.4% GSTM1-null population. GSTT1-positive genotype was found to be 87.5% and GSTT1-null showed 12.5%. The NQO1 genotype of Maharastrian population showed 52.3% of C/C, 42.48% C/T and 5.18% T/T. The NQO1 of this population does not deviate from the expected Hardy-Weinberg equilibrium. The genotype frequencies GSTM1 and GSTT1 of the population when compared with other ethnic groups of Asia and Caucasians show distinct nature of Maharastrian population from other Asian and Caucasian population.     

Heavy metal (Cu, Zn, Cd and Pb) contamination of vegetables in urban India: a case study in Varanasi

The contributions of heavy metals in selected vegetables through atmospheric deposition were quantified in an urban area of India. Deposition rate of Zn was recorded maximum followed by Cu, Cd and Pb. The concentrations of Zn and Cu were highest in Brassica oleracea, Cd in Abelmoschus esculentus and B. oleracea, while Pb was highest in Beta vulgaris. Heavy metal pollution index showed that B. oleracea was maximally contaminated with heavy metals followed by A. esculentus and then B. vulgaris. The results of washing showed that atmospheric deposition has contributed to the increased levels of heavy metals in vegetables. Both Cu and Cd posed health risk to local population via test vegetables consumption, whereas Pb posed the same only through B. oleracea. The study concludes that atmospheric depositions can elevate the levels of heavy metals in vegetables during marketing having potential health hazards to consumers.     

Validation of a standardized portable fluorescence method for determining trace beryllium in workplace air and wipe samples

Beryllium is widely used in industry for its unique properties; however, occupational exposure to beryllium particles can cause potentially fatal disease. Consequently, exposure limits for beryllium particles in air and action levels on surfaces have been established to reduce exposure risks for workers. Field-portable monitoring methods for beryllium are desired in order to facilitate on-site measurement of beryllium in the workplace, so that immediate action can be taken to protect human health. In this work, a standardized, portable fluorescence method for the determination of trace beryllium in workplace samples, i.e., air filters and dust wipes, was validated through intra- and inter-laboratory testing. The procedure entails extraction of beryllium in 1% ammonium bifluoride (NH(4)HF(2), aqueous), followed by fluorescence measurement of the complex formed between beryllium ion and hydroxybenzoquinoline sulfonate (HBQS). The method detection limit was estimated to be less than 0.02 microg Be per air filter or wipe sample, with a dynamic range up to greater than 10 microg. The overall method accuracy was shown to satisfy the accuracy criterion (A< or = +/-25%) for analytical methods promulgated by the US National Institute for Occupational Safety and Health (NIOSH). Interferences from numerous metals tested (in >400-fold excess concentration compared to that of beryllium) were negligible or minimal. The procedure was shown to be effective for the dissolution and quantitative detection of beryllium extracted from refractory beryllium oxide particles. An American Society for Testing and Materials (ASTM) International voluntary consensus standard based on the methodology has recently been published.     

Impact assessment of a hydroelectric project on the flora in the Western Himalayan region based on vegetation analysis and socio-economic studies

This study provides an overview of the impacts of a proposed hydroelectric power project in the Western Himalayan region in India, using a primary database on floristic diversity and vegetation analysis. The remote sensing data revealed that in the submergence zone only mixed deciduous forest that occupies 807.5 ha area and has a wood biomass volume of 4,027,503 m³ is likely to be lost due to impoundment. A total of 165 plant species found in the submergence zone also occur in the influence and free draining catchment area of the project. In the influence zone of the project area only one tree species (Acer oblongum) is found under conservation threat category, which is also present in the free draining catchment of the project. The project affected population (6716 people) residing in the submergence and influence zone depend upon the surrounding forests for fuel wood, fodder, wild edibles etc., and most likely they will settle in the nearby areas, thus mounting more pressure on residual forests of the influence zone for various forest products. Further, from the vegetation analysis it is evident that several tree species (e.g. Lannea coromandelica, Terminalia alata, T. bellerica etc.), may face more pressure from exploitation as they provide a number of useful products and are represented in lower numbers in the forests of the project area. To compensate for the loss of various goods and services provided by the forests falling in the submergence zone and to offset the increased pressure of the project affected families on the forests of influence zone, a biodiversity management plan is suggested incorporating socio-economic considerations.     

Differential protection of ethylenediurea (EDU) against ambient ozone for five cultivars of tropical wheat

The antiozonant EDU (ethylenediurea) was used to assess the impact of ambient O₃ under field conditions on five cultivars of tropical wheat (Triticum aestivum L.). EDU solution (0 ppm and 400 ppm) was applied as soil drench (100 ml plant^?1) 10 days after germination (DAG) at an interval of 12 days. EDU-treated plants showed significant increments in stomatal conductance, photosynthetic rate, variable fluorescence, total chlorophyll, ascorbic acid, proline and protein contents and protective enzymes (POX, SOD and APX) activities in HUW468, HUW510 and HUW234 cultivars, while, a reverse trend was observed for lipid peroxidation. EDU application restored grain yield significantly by maintaining higher levels of antioxidants, metabolites and enzymes in cultivars HUW468 and HUW510. Sonalika and PBW343 showed least response of measured parameters under EDU treatment suggesting their greater resistance to O₃. EDU, thus proved its usefulness in screening suitable wheat cultivars for areas experiencing elevated concentrations of O₃.     

Response of ultraviolet-B induced antioxidant defense system in a medicinal plant, Acorus calamus

Ultraviolet-B (UV-B) radiation generates an oxidative stress in plant cells due to excessive generation of reactive oxygen species (ROS). ROS can denature enzymes and damage important cellular components. In the present study, an important medicinal plant Acorus calamus (Sweet flag) was subjected to two doses of supplemental UV-B radiation (sUV-B): sUV1 (+ 1.8 kJ m(-2) d(-1)) and sUV2 (+3.6 kJ m(-2) d(-1)) to evaluate the relative response of antioxidant defense potential. Stimulation of activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) was observed at initial growth period while the activities of CAT and SOD decreased at later age of sampling. sUV-B induced lipid peroxidation (LPO) was observed showing alteration of membrane properties. No definite trend of change was observed for ascorbic acid (AsA), while increments in thiol, proline, phenol and protein contents were observed due to sUV-B. Results suggested that sUV-B radiation may stimulate the enzymatic and non-enzymatic defense system of Acorus plants, showing its better adaptation at lower dose of sUV-B.     

Differential effects of hydroxylamine and ethyl methane sulphonate on potato virus X

The Science of Nature -