http://nopr.niscair.res.in/handle/123456789/4980 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/5153 Title: Convective effects in air layers bound by cellular honeycomb arrays <br/> <br/>Authors: Kumar, Pawan; Kaushika, N D <br/> <br/>Abstract: Rayleigh-Benard convection in a fluid (air) layer in presence of transparent cellular structure (honeycomb) is reviewed for application to the engineering design of transparent insulation materials devices. The explicit numerical computations of Rayleigh numbers of the characteristic equation at higher wave numbers corresponding to the onset of instability are carried out. Results highlight a new facet of theory that it can indeed be used to estimate the critical Rayleigh number, which corresponds to the layer bound by vertical walls of cellular structure. A relationship between wave number and aspect ratio of honeycomb structure is evolved. Subsequently the stability of inclined fluid layer is considered and base flow existence and the need for its consideration in terms of Nusselt number is discussed. An outline of governing equations of the square celled air temperature, vorticity, stream functions and velocity are presented and it is found that the Nusselt number has a value in the range 1-1.5 for a wide range of Rayleigh numbers in near critical Rayleigh regime. This range may be considered as a trade off region for the engineering design of honeycomb devices. Convection can be suppressed by varying the aspect ratio of honeycomb cell. Honeycomb structure of aspect ratio 10-15 seems suitable for suppression of convection in air layer of depth 5-20 cm for temperature difference (<img src='/image/spc_char/delta.gif'>T)of 20 to 120°. <br/> <br/>Page(s): 602-612 Fri, 29 Jul 2005 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/5148 Title: Optimization of apple pomace based medium and fermentation conditions for pigment production by <i style="">Micrococcus </i>species <br/> <br/>Authors: Attri, Devender; Joshi, V K <br/> <br/>Abstract: The effect of carbon and nitrogen sources on yield and carotenoids production by <i style="">Micrococcus </i>sp. was studied in apple pomace (AP) based medium. AP (20 g/l) have shown maximum yield of biomass and carotenoids in the basic medium. The addition of fructose (0.2%) to AP-based medium gave the maximum yield of biomass (4.13g/l) and carotenoids (9.97 mg/100g). Among the different nitrogen sources tried, sodium nitrate (0.2%) gave the highest production of biomass (4.63 g/l) and carotenoids (9.87 mg/100g). Beyond 0.2% concentration, there was decrease in biomass and carotenoids. Optimum parameters standardized were: temp, 35 ^oC; incubation period, 96 h; and pH 6.0. <br/> <br/>Page(s): 598-601 Fri, 29 Jul 2005 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/5146 Title: Air pollution dispersion studies through environmental wind tunnel (EWT) investigations: A review <br/> <br/>Authors: Sharma, N; Chaudhry, K K; Rao, C V Chalapati <br/> <br/>Abstract: <smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="country-region"><smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="City"><smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place"> Environmental Wind Tunnel (EWT) has emerged as one of the most widely used technique to carry out a wide rage of air pollution studies. EWT technique has shown promising results in analyzing complex fluid dynamical problems that are presently intractable through analytical/numerical technique. In EWT, the emission conditions, different meteorological situations, terrain and topographical features can be changed at will and useful data translatable to the real life situations can be obtained. Recently, EWT technique is being used to bridge the gap between the actual field conditions and various mathematical assumptions. Most of the EWTs throughout the world are located in few industrialized countries. In India, an EWT has been constructed and put operational at the Indian Institute of Technology (IIT), Delhi. This facility is first of its kind in South Asia, the nearest in the east is in Japan and that in the west is in Europe and USA. It is expected that with the operation of first EWT in India, an excellent and world-class facility will be made available to the Indian scientists and researchers. At present, the investigations are being carried out to understand the complex vehicular pollution dispersion phenomena under urban environmental conditions for Indian traffic and climatic conditions. </smarttagtype></smarttagtype></smarttagtype> <br/> <br/>Page(s): 549-559 Fri, 29 Jul 2005 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/5138 Title: Effect of 2-mercaptoethanoic acid treatment of fluted pumpkin waste (<i style="">Telfairia occidentalis </i>Hook. f.) on the sorption of Ni²⁺ ions from aqueous solution <br/> <br/>Authors: Jnr, M Horsfall; Spiff, A I <br/> <br/>Abstract: Differential sorption behaviour of pure and acid treated pumpkin waste biomass on the sorption of Ni²⁺ion from aqueous solution was assessed by an ensemble of sorption techniques. Biomass was chemically treated by 0.50 <i style="">N</i> and 1.00 <i style="">N</i> 2-mercaptoethanoic acid solutions. Sorption capacity calculations from Langmuir isotherm model reveals the following amounts of Ni²⁺ions bound per gram of biomass: pure, 12.69; 0.5 <i style="">N</i> acid treated, 40.0; and 1.0 <i style="">N</i> acid treated, 42.19 mg/g. The sorption probabilities for Ni²⁺onto pure and differentially acid treated biomass were 0.19, 0.22 and 0.31 respectively. Acid treatment significantly enhanced the adsorption potential, adsorption density and sorption probability of biomass towards the metal ion. The negative values of E_a suggest that sorption process is exothermic. This study demonstrates that fluted pumpkin waste could be utilized as low cost, environment friendly biosorbent for the removal of Ni²⁺ and other trace metals from aqueous solution. <br/> <br/>Page(s): 613-620 Fri, 29 Jul 2005 22:58:59 GMT