Archives-May 2012

The Next Generation Wireless Networks (NGWN) are heterogeneous in nature and Call Admission Control (CAC) in NGWN is a challenging problem. User differentiation is becoming increasingly important to the service providers as Quality of Service (QoS) requirements vary amongst users. The number of users in the network is directly controlled by CAC and hence must be carefully designed to guarantee the varying QoS needs of users. This paper proposes a channel partitioning model for CAC in NGWN by taking into account the users QoS needs and the simulation results for the call blocking probability of different user classes is presented.

Biofuel, is committed to becoming a worldwide leader in the development and deployment of renewable energy resources. Biofuels have been one of the substances at the forefront of the discussion. A number of sources for the production of biofuels have been considered. The production of energy from renewable and waste materials is an attractive alternative to the conventional agricultural feed stocks. Algae mainly microalgae have recently gained a lot of attention as a new biomass source for the production of renewable energy. Microalgae can provide several different types of renewable biofuel including methane produced by anaerobic digestion of the algal biomass, biodiesel derived from microalgal oil and photobiologically produced biohydrogen. Algae have received global attention as a renewable resource of biodiesel and may play an important role as a component contributing to the economic growth of the northeastern (NE) region of India. Exploitation of algal diversity and its sustainable use as a feedstock for biodiesel through biotechnological interventions is the need of the hour to ensure future energy security. Many microalgae are exceedingly rich in oil which can be converted to biodiesel using existing technology. In dramatic contrast with the best oil-producing crops, microalgal biodiesel has the potential to be able to completely displace petroleum-derived transport fuels without adversely affecting supplies of food and other agricultural products.

Students were to research on a particular industry sector, study their governance and point out the good, bad and ugly practices of their governance. Here, in this report, I have selected Swissair airline sector for my study. Swissair, considering their dramatic fall (it used to be one of the best airlines and nation’s pride that apparently got market failure, gone under debt in 2002 and the government had to bail it out) was a very good choice for this report. The structure of this report is very simple since the scope was just to point out governance and ethics practices of this company. In my report, I have given a little background information about the company that is followed by the bad governance and ethics practices in Swissair. These bad points are followed by the ugly practices. Now when Swissair saw itself failing they started taking steps that included some governance and ethical changes as well. I have tried to include them in the good points. Overall, my report is a short paper describing governance in Swissair, where I have tried my best to include all major and critically important points.

Rice husk, agricultural waste material of environmental  impact,  was carbonized at temperatures of 300 - 600⁰C in an oven for 2h, after which its adsorption capacities was investigated for the adsorption of acenaphthene in synthetic aqueous solution, at increasing concentrations (50–150mg/L). The yields of carbon obtained from the raw rice husk ranged from 20 - 40 % (w/w), while the adsorption capacities of rice husk increased with increasing carbonization temperature and increasing initial concentration of acenaphthene. The removal efficiencies of the rice husk increased from 71.37 - 80.56% as the carbonization temperature increased from 300 - 600⁰C, but decreased with increasing initial concentration of acenaphthene. The adsorption equilibrium data obtained, fitted well to the Freundlich, Langmuir, Temkin and Dubnin-Radushkevich isotherms with minimum correlation values of 0.9981, 0.9262, 0.9667 and 0.9215, respectively, although, generally decreases with increasing carbonization temperature. The error analysis showed the order of suitability of the isotherm models selected to be Temkin > Freundlich > Dubnin-Radushkevich > Langmuir. This study shows that carbons rice husk possesses high potency of being used as activated carbon for the removal of acenaphthene from wastewater.

Mobile banking system plays a major role in mobile commerce. As wireless networks are existed, today new generation of electronic commerce applications are emerged and expanded, that are known as mobile commerce. In this field one of services that served in bank industry with cell phones is mobile banking. Although many studies have been conducted to assess users’ satisfaction with mobile applications, none has focused on ranking the effective alternatives. So the goal of this article is to extract the effective alternatives of user’s satisfaction and rank them with VIKOR. The research extract 42 alternatives based on Delone and McLean’s Revised Model and chooses 21 effective alternatives by expert’s ideas and then ranking them. VIKOR shows that data accuracy and security are ranked as first and second alternatives.

The maximum ground level air concentration from elevated point source over simple terrain is estimated using previous work by Essa et al. (2007). The eddy diffusivities in linear forms are used. The critical of the wind speed, plume height and downwind distance are estimated. The results of the maximum concentrations are applied using meteorological data of a plant stack located in, Inshas, Egypt.

Food substances worthy of consumption have nutritive values of great dietary effect which in the first place attract people to eat them. As they contain the required nutrients, they also may contain some anti-nutritive substances which may or may not be in trace amounts. In this study sixteen commercial baby foods, comprising five different brands, available on the Ghanaian market have been analysed for their anti-nutrients content (oxalate and cyanogenic glycoside) adopting the method of Andrew and Visser (1951) and the Official Methods, (AOAC 915.03, 17^th Ed) together with their mineral Fe and Zn content using the method of Hernandez et al. (2004) with modification.  The total oxalate concentration levels in the 16 selected cereal brand baby food products ranged from 0.08 to 0.27 mg/g. The HCN concentration levels in the 16 selected cereal brand baby food products ranged from 0.07 to 0.36 mg/g. The concentration levels of Fe and Zn in the brand samples ranged between 24.12-220.76 mg/kg and 0.82-33.88 mg/kg respectively. The concentration levels ranged between 1.67-12.88 mg of total oxalate per serving for BFN-3 (rice based product) and BFB-2 (milk and honey based product) respectively whilst that of cyanogenic glycoside is 1.96-17.06 mg per serving for BFF-1(Lactea based product) and BFN-1 (fiber based product) respectively. Fe concentration levels ranging between 0.68-4.41mg per serving for BFC-3 (fruit and wheat based product) and BFN-4 (oat based product) respectively whilst that of Zn is 0.01- 1.15 mg per serving for BFBN-3 (muesli with apple) and BFN-3 (rice based product). Fourteen of the 16 cereal brand baby foods contained less than 10 mg oxalate per serving, defined as a low oxalate food. Differences in anti-nutritional factors within the brands were observed. The results of the analysis suggest that  oat based product, appear to offer better nutritional value partly due to its low ANF coupled with its relatively high mineral iron content.

This paper presents the comparison of hybrid multilevel inverters for different voltage and power applications. Hybrid multilevel inverters improve the number of the output voltage level based on a hybrid connection of power cells. Therefore, a given number of levels can be synthesized by several multilevel configurations, significantly increasing flexibility and complexity in the design of hybrid multilevel inverter. The purpose of the circuits presented here is to minimize the reverse voltage stress and the harmonic distortion of the voltage applied to the load. As a characteristic of the proposed cells, some of the switches operate at low frequency while others are switched at high frequency. Different topologies are discussed and reviewed in brief. Voltage sharing and low output-voltage distortion are achieved. This paper presents a survey of different topologies, control strategies and modulation techniques used by these inverters.

The in vitro antimicrobial activity of crude methanolic extracts of various plant parts of Phyllanthus niruri was investigated. The extracts exhibited antimicrobial activities with zones of inhibition ranging from 6 to 16 mm. All the extracts exhibited appreciable activity against all the clinically important bacterial and fungal species clinically investigated. Maximum Inhibition zone (16mm) was observed in seeds against Staphylococcus aureus and minimum in roots (5mm) against E. coli. Phytochemical screening revealed the presence of carbohydrates, proteins, alkaloids and flavonoids in the extracts. The antimicrobial activity of the extract was compared with the standard drugs. The ability of the crude extracts of P. niruri plant parts to inhibit the growth of various bacteria and fungi showed its broad spectrum antimicrobial potential, which may be employed in the management of microbial infections.

Today the world is at the risk of environmental disarray. The main reason is population explosion. The result of the uncontrollable population, forces us to maintain the inventory of all products at a higher level. The suppliers are comparatively lesser than buyers. To retain the confidence of the buyers, the suppliers seek logistics and packaging for the deliverance of the goods to the customers at the right time and in the right manner respectively. This paper deals with an Economic Order Quantity model (EOQ) which associates the package cost along with the costs of ordering, purchasing and holding. The need for packaging and the impact of its inclusion in the classical EOQ model together with transportation cost are discussed.