Budget constrained energy conservation-an experience with a textileindustry

The conservation and efficient use of energy in industry has, for a long time, been a priority of the Government of India. In anticipation of the enactment of federal legislation on energy management for industry, the State of Government of Tamilnadu, Kerala, and other Southern States, made energy audits mandatory for large-scale energy-consuming industries. So among industrial consumers, the aspect of energy conservation is gaining due importance of the realization that "Energy Saved is Energy Produced and that too at Economical Cost". This paper shares the experiences of the authors on energy conservation projects carried out in a textile industry situated in India's Tamilnadu State. Economic and efficient measures of energy conservation have been followed subject to budget constraints and the effect of such measures were realized through reduction in energy costs with the added advantage of environmental safety     

First differential of temperature dependent ultrasonic parameters as an effective tool for identifying precipitation reactions in a slow heat-treated 8090 Al–Li alloy

Ultrasonic velocities and attenuation measurements have been carried out to characterise the fine scale precipitation events in a slow heat-treated 8090 Al–Li alloy. The alloy was subjected to a slow heating (at the rate of 10 K h⁻¹) to the temperature of 463 K, before and after solution annealing at 803 K for 1 h. The changes in bulk modulus, Young's modulus and Poisson's ratio have been obtained from the ultrasonic velocity data. The variation in hardness and density has been found to be consistent with the changes in velocities and elastic constant. The ultrasonic on-line measurements from 300 to 623 K reveal clearly all the four transitions, including the formation of GP zones at 368 K, formation of δ′ at 470 K, dissolution of δ′ at 532 K and the formation of equilibrium S′ and δ phases at 590 K. The first differential of temperature dependent ultrasonic parameters is found to be particularly effective in clearly diagnosing all the fine scale precipitation/dissolution events. Differentiation between the precipitation and dissolution type reactions is also possible from careful analysis of the first differential plots.     

Fog collection as a source of fresh water supply in the Kingdom of Saudi Arabia

In order to harvest water contained in fog, the topographical features and the climatic conditions of 27 cities in the Kingdom of Saudi Arabia were studied. The topography, altitude and orientation are some of the factors that determined the selection of the site. It was identified that the southwest of the region in the kingdom was the most suitable location for the fog‐collection process. In order to evaluate the effectiveness of fog water collection and the site, three identical standard fog collectors (SFCs) with two different local collection materials were designed and manufactured. Experiments were conducted at two different locations in the area close to Abha, namely Soodha. The maximum amount of water collected was 22.9 L/m² in a day and 7.25 L/m² in a 2‐h period. It was found that there was a high probability of fog when the relative humidity was higher than 95%. The results from the chemical analyses of eight sets of fog water samples collected were compared with World Health Organization drinking water standards. It was found that the level of heavy metals was negligible and the level of Fe was marginally high for the first flush only. The study indicates that in terms of both quality and magnitude of yield, fog is a viable source of water and can be successfully used to supplement water supplies in the fog‐prone regions of the kingdom.     

Structural Basis for Intumescence – Part III – Thermal Degradation Study of Intumescent Polymers Containing Spirophosphorus Moiety in the Backbone

3,9-Dichloro-2,4,8,10-tetraoxo-3,9-disphosphaspiro-[5.5]-undecane-3,9-dioxide (spiro) was melt condensed with structurally different dihydric phenols to form poly aromatic spirophosphates. The thermal volatilization analysis showed eruptive release of gases above 300°C and the temperature region of release depends on the nature of the aromatic units incorporated in the polymer backbone. The thermal degradation in nitrogen atmosphere indicated the formation of phenol, substituted phenols, aromatics, alkyl and alkenyl substituted aromatics and condensed aromatics like azulenes, indanes and fluorenes. The source for the formation of these products is the spiropentadiene released from the spiro unit during degradation.     

Isopropylation of ethylbenzene over MCM-22 molecular sieve

MCM-22 materials (Si/Al ratios 24, 50 and 75) were synthesized and characterized. The catalytic activity was examined in the vapour phase isopropylation of ethylbenzene with isopropyl alcohol. Based on ethylbenzene conversion, the order of activity of the catalysts is found to be MCM-22(50) > MCM-22(24) = MCM-22(75). The selective formation of p-isopropyl ethylbenzene (p-IPEB) suggests that the reaction occurs mainly inside the 10-membered ring channel. The time on stream study over MCM-22(50) showed steady conversion for 6 h with nearly the same selectivity to p-isopropyl ethylbenzene (p-IPEB) and o-isopropyl ethylbenzene (p-IPEB).     

A novel technique to synthesize hydroxyapatite at low temperature

Hydroxyapatite (HAP), a well known biomaterial, was synthesized by a novel technique using agarose gel in a high alkaline medium at a relatively low temperature 85 °C. The XRD analysis of the as-synthesized material revealed the absence of either brushite or or β tricalcium phosphate phases. Sintering studies at 750 and 1200 °C revealed the conversion of HAP into pyrophosphate without leaving any additional phases. A considerable decrease in the transformation temperature of HAP phase to that of -calcium pyrophosphate (-CPP) phase was found compared to the reported values.     

Phosphoric acid modified-Y zeolites: a novel, efficient and versatile ion exchanger

Large pore HY zeolite was modified with phosphoric acid by wet method. The modified zeolite was converted to Na(+) form using aqueous NaHCO(3) solution(.) The Na(+) form of modified zeolite, represented as PNa(2)Y, was characterized by XRD, BET surface area, SEM, and AAS techniques. The XRD analysis showed diffraction patterns same as that of parent HY zeolite, as a result there has been no structural degradation during modification. It was then tested for sorption of Cu(2+) ions from aqueous solution. The Cu(2+) content of the solution was analyzed by AAS. PNa(2)-Y shows higher sorption capacity ( approximately 40%) than the parent Na-Y ( approximately 23%) zeolite, which is attributed to the double of amount Na(+) content in PNa(2)-Y compared to the Na-Y zeolite. Equilibrium modeling data were found to fit more to the linear Langmuir model than the Freundlich model. The thermodynamic parameters such as change in free energy (DeltaG degrees ), enthalpy (DeltaH degrees ), and entropy (DeltaS degrees ), were also calculated. These parameters confirmed that the sorption of Cu(2+) is feasible, spontaneous and endothermic.     

Solar photocatalytic degradation of azo dye: comparison of photocatalytic efficiency of ZnO and TiO2

The photocatalytic activity of commercial ZnO powder has been investigated and compared with that of Degussa P25 TiO₂. Laboratory experiments with acid brown 14 as the model pollutant have been carried out to evaluate the performance of both ZnO and TiO₂ catalysts. Solar light was used as the energy source for the photocatalytic experiments. These catalysts were examined for surface area, particle size and crystallinity. The effect of initial dye concentration, catalyst loading, irradiation time, pH, adsorption of acid brown 14 on ZnO and TiO₂, intensity of light and comparison of photocatalytic activity with different commercial catalysts were studied. The progress of photocatalytic degradation of the acid brown 14 has been observed by monitoring the change in substrate concentration of the model compound employing HPLC and measuring the absorbance in UV–Visible spectrophotometer for decolourisation. The photodegradation rate was determined for each experiment and the highest values were observed for ZnO suggesting that it absorbs large fraction of the solar spectrum and absorption of more light quanta than TiO₂. The complete mineralisation was confirmed by total organic carbon (TOC) analysis, COD measurement and estimation of the formation of inorganic ions such as NH₄⁺, NO₃⁻, Cl⁻ and SO₄²⁻.     

Prominent catalytic activity of mesoporous molecular sieves in the vapor phase dehydration of cyclohexanol to cyclohexene

Cerium incorporated KIT-6 mesoporous materials were synthesized through direct hydrothermal method and characterized by using X-ray diffraction (XRD), nitrogen sorption isotherm (BET), Fourier transform infrared spectroscopy (FT-IR), inductively coupled plasma -atomic emission spectroscopy (ICP-AES), diffuse reflectance ultraviolet visible spectroscopy (DRS-UV-Vis), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) methods. It appeared that stable cerium ions were inserted into the silica framework of KIT-6, thus generating acid properties in their host materials. The catalytic activity of Ce-KIT-6 materials was evaluated in the vapor phase dehydration of cyclohexanol to cyclohexene and dicyclohexyl ether at different temperatures with various Si/Ce molar ratios. Ce-KIT-6 (25) showed higher activity with 54% cyclohexanol conversion and 64% selectivity to cyclohexene. The catalytic results indicated that Ce-KIT-6 mesoporous materials could be used as versatile and stable acid catalysts.     

Ultrasonic velocity measurements for estimation of grain size in austenitic stainless steel

Ultrasonic velocity measurements have been used to estimate average grain size in an AISI type 316 stainless steel. For precise ultrasonic transit time measurements, the pulse-echo-overlap technique has been used. Master graphs relating ultrasonic velocity with metallographically obtained grain size have been generated. Using these graphs, grain sizes in new specimen have been obtained. The results indicate that grain size can be predicted with good confidence level using ultrasonic velocity measurements. Shear waves are found to be more sensitive for grain size measurement, as compared to longitudinal waves. The grain size estimated by velocity measurements is found to be more accurate when compared to that obtained by attenuation measurements.