Archives-April 2011

Ceramic whiteware represents one of the most complex ceramics, formulated from a mix of china clay, ball clay and quartz are sintered to conform a ceramic composite. Ceramic whiteware has excellent technical characteristics. Nowadays, research of new materials, for example non-hazardous wastes, that are able to replace the traditional fluxing agent without changing the process or quality of the final products has been realized. The aim of this work is to study the possibility of the use of quartz, in ceramic whiteware mixtures, for manufacturing of electrical ceramic whiteware bodies. It was prepared by mixtures containing different amounts of china clay, ball clay, feldspar and quartz. The samples were fired reaching different maximum temperatures in the range 950-1250 ºC, with a soaking time of 1 hour. The fired samples were characterized and the use of small amounts of quartz in addition with whiteware samples showed good results of mechanical technological properties. The optimum quartz percentage (25%) S1 samples at 1250 ?C gives the maximum bending strength.

The use of a latent heat storage system using Phase Change Materials (PCM) is an effective way of storing thermal energy (solar energy, off-peak electricity, industrial waste heat) and has the advantages of high storage density and the isothermal nature of the storage process. In the present era the utilizations of electricity and other conventional modes are quite in effective to the present demand and in other hand the role of alternative energy resources which compensates the present energy demands of the world will be not enough for the future. Meanwhile by the year 2020 the renewable energy resources are depleting so that it will become in need of very high energy demand due to over population in India comparing to the world resources and their populations. Now it clearly shows that trapping the solar energy and storing the heat by means of suitable PCMs will give other hand support to solve the energy crisis will help to bring out a new milestone in energy storage revolutions. It has been demonstrated that, for the development of a latent heat storage system, choice of the PCM plays an important role in addition to heat transfer mechanism. The information on the latent heat storage materials and systems is enormous and published widely in the literatures. In this paper, an attempt has been made to provide information from the previous works on PCMs and latent heat storage systems. This review may have been planned to be useful to the scientists and researchers to investigate more on PCMs.

In this paper, we apply our generalized theorem on summability to derive some approximation formulae of the series involving quadruple hypergeometric function K12. This work may be useful in the field for computation of the solution of hydrodynamical problems. 2000 AMS Classification: 32A05, 33C47, 33C70, 33C90, 40A05, 40A25, 40D05.

Graft copolymerization of acrylamide (AAm) on Gum Karaya GK using diode laser (532 nm) was investigated. The results showed that, the optimum conditions to achieve efficient graft copolymerization were: 60 minutes laser irradiation time and 0.5 gm of GK, 0.142 gm of acrylamide (monomer). The percentage of graft efficiency and percentage of graft yield were 28.00%, and 98.59%, respectively. The graft copolymers were characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Thermogravimetric analysis (TGA) and Scanning Electron Microscope (SEM) which proved a successful production of GK-g-AAm. Thus, Laser irradiation was found to be effective and clean method for producing GK-g-AAm.

In Tilapia aquaculture, it is more desirable to culture all male (monosex) population because they grow bigger and faster. The synthetic steroid hormones such as 17-?-methyl testosterone are commonly used to reverse sex in tilapia. Due to its latent health and environmental hazards, attention is presently being focused on the use of alternatives, such as plant extracts called phytochemicals. This study investigated the phytochemical “genistein” as a possible enzymatic aromatase inhibitor that could modulate the sex differential response in the gonad of sexually undifferentiated tilapia. Experimental diet supplemented with genistein (500mg/kg) along with a control diet were evaluated in the feeding of three days old tilapia fry (6mg-8mg) for eight weeks. Result shows that the presence of dietary genistein did not have any significance positive effect on the weight gain, SGR (%) and survival (%), although higher number of males were produced in the genistein fed fish but the phenotypic sex ratio was not significantly different (p>0.05) from the control.

Reliability assessment popularly known as Weibull analysis is an exercise primarily concerned with reliability estimation and prediction with which failure process of a system can better be analyzed. Many situations like modeling failure processes, decision of effective maintenance policy, estimation of maintenance float factors, downtime assessment and reduction greatly rely on the parameters of the life distributions fitted to the failure data. As the Weibull distribution involves transcendental equation, determining parameters is quite difficult task. To this effect, a Nomograph is developed and presented in this paper to closely determine the Weibull parameters. The paper articulates the development of Nomograph and procedure for its implementation. Results and discussions carried out proves statistically that the results obtained using the Nomograph are better than the commonly used its counterparts.

The Mechanical ore handling plant in Goa, India comprises of receiving and shipping section. Receiving section deals with the unloading of ore from barge. This is accomplished by wire rope operated grab un-loader. Since the unloading is being done round the clock, frequent failure of wire rope is observed. The unloading process gets disrupted when the wire rope fails. This results in significant loss in unloading hours. Detailed investigation is carried out to reduce the down time and recommendations regarding maintenance are made in this paper. Details of the maintenance policy model and results and discussions carried out are presented in this paper.

The molecular vibrations of 2-bromo-4,6-dinitroaniline (BDNA) were investigated in solid phase, at room temperature by FT-IR and FT-Raman spectroscopy. The molecular geometry and vibrational frequencies of BDNA in the ground state were calculated by using the Hartree-Fock (HF) and density functional theory (DFT) methods (B3LYP) with 6-311++G** as basis set. Comparison of the observed fundamental vibrational frequencies of BDNA with calculated results by HF and density functional methods indicates that B3LYP is superior to HF method for molecular vibrational problems. The Mulliken atomic charges have also been computed at HF/6-311++G** and B3LYP/6-311++G** level. Finally the calculated HOMO and LUMO energies show that charge transfer occur in the molecule.

Entrepreneurship is a growing phenomenon in the competitive markets. In the past, marketing and entrepreneurship have been regarded as two distinct fields of study. A growing awareness of the importance of entrepreneurship and innovation to marketing, and of marketing to successful entrepreneurship, has recently led to attempts to combine the two disciplines as “entrepreneurial marketing”. The purpose of this paper is to address entrepreneurship perspectives, differences between small firms and entrepreneurial firms, entrepreneurial marketing processes, determinants of entrepreneurship and its implications for marketing, and finally, opportunities for marketers.

The water quality index (WQI) method rather than the conventional water quality standard approach was applied in evaluating the surface water quality of the Jakara basin, Kano, Northern Nigeria. The objective of this study is to provide water quality index reference values and pattern for targeted environment. Thirty surface water samples were collected: twenty three samples along River Getsi and seven surface water samples along the main channel River Jakara. Twenty three quality parameters namely: pH, temperature, turbidity, electrical conductivity, dissolve oxygen, biochemical oxygen demand, Fecal Coli form, total solids, nitrates, phosphates, cobalt, iron, nickel, manganese ,copper, sodium, potassium, mercury, chromium, cadmium, lead ,magnesium, and calcium were analyzed. The study used nine physicochemical and bacteriological parameters converge into single value as suggested by National Science Foundation-Water Quality Index (NSF-WQI). The result reveled that S2,S3,S4,S5,S12,S15,S17 of the River Getsi fall under very bad water quality while other sampling points within the same stream shows Bad water quality. On the other hand out of the seven sampling points within River Jakara, only S25 shows Very bad, others fall within Bad water quality. In general water in the Jakara basin fall under very bad category and pose a danger in any form of water consumption. The water quality index scheme performed better in water quality pollution trend analysis due to its sensitivity to changes in water quality at different point in time.