Iranica Journal of Energy and Environment (IJEE)

265-274

Authors: Krityanand Kumar Mahatman, Neha Garg, Ranjeeta Chauhan, Anil Kumar

Xylanase (EC. 3.2.1.8) has been isolated from an alkalo-thermophilic bacteria, Bacillus halodurans strain KR-1 isolated from the soil near river bed at Indore. The bacteria secreted xylanase in the growth medium in the presence of xylan. The production of the enzyme was induced in the presence of glucose, mannose, lactose and maltose whereas presence of starch, cellulose and sucrose retarded in enzyme production. The presence of casein, peptone, sodium nitrate and potassium nitrate as nitrogen source in the growth medium resulted in more xylanase production, whereas presence of ammonium sulfate, ammonium nitrate and yeast extract resulted in lesser enzyme production. The enzyme has been partially purified using sodium sulfate fractionation, DEAE-cellulose and Sephadex G-200 chromatographies. The molecular weight of the enzyme has been found to be 45±02 kDa as determined by Sephadex G-200 chromatography as well as sodium dodecyl sulfate polyacrylamide gel electrophoresis. The enzyme protein is monomeric exhibiting maximum activity at pH 9.0. The optimum temperature for exhibiting maximum activity has been found to be 40oC. The metal ions viz. Mg2+ and Fe2+ when present in the enzyme assay medium stimulated the xylanase activity, whereas Hg2+, Co2+ and Mn2+ strongly inhibited the enzyme activity. The Km value for birchwood xylan was calculated to be 12.0 g/l.

280-286

Authors: Neeta Sharma, Seema Rana, Anunidhi Sharma

The densities, viscosities and ultrasonic velocities of binary mixtures of methanol with acetonitrile and dimethyl formamide have been determined at 298.15, 303.15, 308.15 and 313.15 K over the whole composition range. From the experimental data the values of compressibility (Ks), excess compressibility (Kse) and excess viscosity (ηe¬) have been calculated. The results are discussed and interpreted in terms of molecular package and specific interaction predominated by hydrogen bonding. The data at various temperatures also provide an opportunity to study the effect of temperature on the sign and magnitude of the deviation in viscosity and compressibility. Results show that excess properties are found to be either negative or positive depending on the molecular interactions and the nature of liquid mixtures.

293-298

Authors: S. H. Sengar, A.K. Kurchania

Dual purpose solar oven (DPSO) was designed and constructed. It observed that by using the new design of solar oven, both function of cooking and drying were possible for meeting the requirement of a family. The maximum stagnation temperature of 119°C and water temperature of 93.25°C were obtained in winter in DPSO while using as cooker. The calculated values of figure of merit F in DPSO was 0.119 and the time duration 1 for raising water temperature from 60 C to 90°C in hot box was 120 min. Cooking trials have also been conducted 0.5 kg of rice in 1 kg of water and 0.250 Kg of green gram split washed in one and half hrs in winter while it took about one hour in summer. The maximum temperature of 58 °C was recorded at 14:00 hrs of the day at level of tray no.2 when used as dryer. The time required to dry maize on different trays upto average moisture content 7.13 %( w.w.) for winter and 5.43 %( w.w.) for summer (w.w.)was 420 minute and 360 minute respectively. The total cost of solar oven was worked out to be Rs().2,715. Its pay back period varied between 1.3 to 1.86 years depending upon fuel it replaced.

305-314

Authors: Ritesh Joshi, Rambir Singh

Every year wildfires in Rajaji National Park, north-west India destroys more than 250 hectares of landscape encompassing tall grasslands and mixed forests. This is not only making a negative impact on wild species, but also causing a drastic impact on elephant’s seasonal movements. This study evaluated the impact of three fire seasons in 2007, 2008 and 2009 on the elephants of Chilla and Haridwar forest ranges. The 2008 forest fire burned 95 (0.64%) hectare of the Chilla forest followed by 2007 (75 hectare, 0.50%) and 2009 (60 hectare, 0.40%) whereas the 2007 fire burned 120 hectare (1.40%) of Haridwar forest followed by 2009 (105 hectare, 1.23%) and 2008 (95 hectare, 1.11%) fires. Scarcity of natural water during dry periods is another major factor which is affecting elephant’s movements within their home range. Chilla and Haridwar forests are currently facing water scarcity as far the elephant distribution is concerned, most of the perennial water sources have shrinked or remaining are on the verge of it, whereas before 2002 all of these water sources were fulfilled with tremendous water. Our review of available evidence suggests that wildfires and shrinkage of natural water sources have caused a catastrophic decline of free-ranging elephants from the Chilla and Haridwar forest ranges. All of these data support the importance of protecting the Rajaji National Park and its adjoining protected habitats as an important elephant range, linking different protected areas in north-west India.

321-325

Authors: K. Varunprasath, Nicholas A. Daniel

The study on some physico-chemical characteristics of River Bhavani at its source and Mettupalayam and Sirumugai has been calculated for the period of one year (July 2007 to June 2008). The sampling points were selected on the basis of their importance. For surface water determination of water quality index becomes essential and pre-requisite. Analysis of some physico-chemical characteristics like water temperature, colour, electrical conductivity, transparency, total suspended solids, total dissolved solids, pÇ, dissolved oxygen,BOD, total alkalinity; total hardness has been done during the investigation period. Increase in temperature, turbidity, pH, electrical conductivity, total solids, suspended solids, dissolved solids, BOD values were higher in Sirumugai station, whereas the increase in total hardness, bicarbonate values were higher in Mettupalayam due to the intensity of expulsion of contamination. The dissolved oxygen values higher in Pillur dam station owing to unpolluted water. The Bhavani river has been facing severe anthropogenic activities, mostly due to municipal sewage and industrial waste and dense population etc.

331-338

Authors: Meriem Azaiez, Ikram Zbali, Saber Ben Abdessalem

Textile cardiovascular prostheses are woven or knitted structures made generally from biocompatible polyester fibres. After production, they have to undergo special treatments before packaging such as compaction. This treatment is necessary to reduce porosity especially for knitted structures, but it can modify poly(ethylene terephthalate) (PET) polymer’s properties. We have studied the effect of chemical and thermal compaction process parameters on physical properties of PET with DSC and XRD techniques. The obtainedresults show changes of glass transition temperature according to compaction parameters. A multiple melting peaks thermograms were observed for untreated and most compacted samples indicating differences between crystallites sizes. The compaction treatment involves an increase of PET crystallites size because of molecular bonds rearrangement among the polymeric chains. With DRX, we have showed crystallites size increases for compacted samples when compared with untreated samples. This increase is particularly important in perpendicular direction to (010) crystallographic plane.

347-351

Authors: Nagaraj Naik, K.S. Jagadeesh, M.N. Noolvi

Four microorganisms isolated from samples of mangrove areas were found to be promising and significantly decolorized spent wash. Incidentally, they showed higher phenol degradation and COD reductionas well. The individual colorants imparting the color to spent wash were fractionated. Degradation of melanoidin and caramel was confirmed by UV and FTIR spectral analysis. Decrease in OD of melanoidin and caramel at their 8 max and appearance of new peaks and changes in functional groups of compounds in the IR spectra with respect to control suggest their degradation. K1 was the best melanoidin (77%) as well as caramel (54%) degrader followed by other three isolates (Ku3, Rtb2 and EB4).

359-366

Authors: Rashid Nizam, S. Mahdi, A. Rizvi, Ameer Azam

The electronic structure and the conductance of carbon nanotube based metal/semiconductor/metal intramolecular junctions are investigated numerically. The nature of electronic states at the interfaces and in the semiconductor section is analysed with the help of tight-binding method. The quantum conductance of the system is calculated in the logical regime and its variations with energy have been observed. These quantum conductances have been compared among the different carbon nanotubes and that have been correlated with the pentagon and heptagon that formed in the intramolecular junction.