Archives-December 2012

This paper describes three phase bi-directional battery charger widely used in Energy storage application. The full bridge scheme is widely used for the high power application. The high-frequency transformer is used for the isolation purpose. This paper describes the design and simulation of a 7.75-kW, full-bridge, bi-directional isolated dc-dc converter with active front-end converter (AFC). The AFC is connected with the 3-phase ac system, which provides 650 to 700 dc voltage to dc-dc converter with lower value of THD (according to IEEE- 915) and improve power factor at input side. The dc-dc converter converts 310V from 650V for charging the battery. Software tool PSIM is used to obtain the simulation result of the converter. The closed loop system is simulated to achieved voltage and current ripple at output side less than 1% rms of rated voltage.

In this modern age, civil engineering constructions have their own structural and durability requirements. Fiber Reinforced Concrete (FRC) is a composite material made primarily from hydraulic cements, aggregates and discrete reinforcing fibers. Fiber incorporation in concrete, mortar and cement paste enhances many of the engineering properties of these materials such as fracture toughness, flexural strength, resistance to fatigue, impact, thermal shock and spalling. The SFRC is a composite material made of cement, fine and coarse aggregates and discontinuous discrete steel fibers. Recently developed an analytical model to predict the shear, torsional strength and bending torsion behavior of fiber reinforced concrete beam with experimental substantiation. However, very little work has been reported in combined torsion and shear. Similarly to beam with conversional reinforcement, the presence of shear may significance influence on torsional strength of fiber concrete beams. Present investigate the mechanical properties like as shear strength, and torsion strength of concrete with different types of steel fiber with constant volume fractions and different aspect ratio.

Computer and network based technologies now hold great potential for increasing the access to information as well as a means of promoting learning and that shape the process of education. Schools and classrooms never before had such universal access to information. Technologies are transforming classrooms into more engaging, collaborative and productive learning environments in which instructions can be customized to student’s specific needs, interests and learning styles. It is also redefining the way educators teach as well as the role they serve – from being the sole source of information to being a guide, facilitator and coach in the learning process.

Recent investigation was performed to explore the cytotoxic activity of various extracts from the leaves of Adina Cordifolia against Ehrlich Ascites Carcinoma (EAC) cell lines using different In-vitro cytotoxic assay at 200µg/ml. Results found that acetone and ethanol extract exhibited significant cytotoxic activity, but higher cytotoxic activity was found in acetone extract.

Willingness to communicate (WTC) is one of the affective factors assumed to influence success in second and foreign language learning. Although the nature of the construct of WTC has been thoroughly investigated in both first and second language its relationship with different modalities of communication in a foreign language has not been studied. The present study explores the possible relationship between WTC and its components and success in foreign language learning. For the purposes of this study a willingness to communicate scale was correlated with a C-Test, which is a measure of general language proficiency. Results show that two out of the three subscales of WTC, namely, willingness to communicate in the school context and willingness to communicate with native speakers of English, were moderately correlated with success in learning English as foreign language as measured by C-Test. The other subscale of WTC, i.e., willingness to communicate with non-native speakers of English was not correlated with success in foreign language learning. Implications of the study are discussed.

Metal monitoring in food, like teas, provides basic information on safety aspects of food in regulatory processes in terms of suitability of food for consumption, as well as its nutritional value. The aim of this work was to measure the total content of Cd, Cr, Co, Cu, Fe, Mn, Pb and Zn in ten brands of commercially available black tea, on the Ghanaian market. All of the samples were microwave-assisted acid digested followed by measurement of the elemental contents by flame atomic absorption spectrometry (FAAS). The concentrations of all the elements varied among the different brands of tea analysed. The total contents of Fe were comparatively higher than the other analyzed elements and varied between 302.95–27.30 µg/g. the ranges of the other elements observed, in µg/g, were as follows: Cr (<0.006-0.90), (3.85- 9.95), Mn (5.34-219.25), Pb (<0.001-2.05) and Zn(2.80-5.50). Cadmium and Cobolt were below detection limits. All values recorded were below the maximum permissible limit set by the WHO.

Nine plantain samples from some communities in the Bibiani mining town and surrounding towns/villages, Abrofrem, Akwawuakrom, Beposo, Besie, Fahiakorbor, Kofikrom, Hwenampori and Old Town – all in the Bibiani-Anhwiaso-Bekwai District – have been analysed using Instrumental Neutron Activation Analysis (INAA) for their levels of the essential elements, Ca, Cl, Cu, K, Mg, Mn, Na and Zn. The aim of the study was to determine the levels of the above essential elements in the plantain samples and also to establish whether the mining activities have had any impact on the levels measured. The concentrations of Ca, Cl, K, Mg and Na referred to as major nutrients measured were in the ranges; 495 – 1895 mg/kg for Ca, 1076 – 3019 mg/kg for Cl, 1800 – 17000 mg/kg for K, 946 – 1337 mg/kg for Mg, and 42.34 – 83.20 mg/kg for Na. The micro/trace elements measured in the samples were in the ranges, 2.55 – 25.44 mg/kg for Cu; 7.40 – 17.20 mg/kg for Mn and 8.25 – 67.96 mg/kg for Zn. The results supported the claim that plantain contains high levels of K and low levels of Na. However, with regard to the RDA/AI values of the various nutrient elements, it could be said that plantain is relatively richer in Mn, followed by Cu and Mg than K. This was due to the fact that relatively lower amount of plantain is required to meet the RDA/AI values of those elements than K. The levels of the nutrient elements measured in the plantain samples did not give any indication of impact of mining activities which could have resulted in loss of soil fertility since the results obtained in this work compared favourably with the results obtained in a similar study conducted by Danso et al (2006) in a non mining area. The only difference observed in the results obtained in this work from that of Danso et al (2006) was with the levels of Mg and Mn. The levels of Mg and Mn measured in this work were however, consistent with the geology of the area as well as their respective RDA/AI values.

During the last two decades, Relation between trade liberalization & increasing exports with the achievement measure to environmental standards has attracted the attention of researchers. In economy area, this subject has been considered with a specific approach. For this purpose, in this article we are tried with the using of dates ways panel, the exports impact of industrial goods, besides the other effective variables on the environment as income, population & Value Added of industry sector for two groups of The organization of economic & development member countries(OECD) and selected developing countries, like Iran in the period of (1991-2007) has been studied on emission measure of carbon dioxide’s greenhouse gas .Also, the effective of variable model on emission measure of sulfur dioxide and nitrogen dioxide as the dependent variable, in OECD member countries has been tested in the period of (1991-2002).The relations between variables with the using of estimation to the ways of fixed impacts , random effects & the way of Generalized method of moments is estimated .The results of model estimation is indicated that the economic development, population growth & the add value of industry sector have positive & significant effect on the emission measure of Pollution in both groups of selected countries. Exports of industrial goods in OECD member countries have positive & significant effect on the emission measure of Pollution & in developing countries have the positive & significant effect too.

Corporate governance is leadership that has the rules, processes, or laws by which businesses are operated, regulated, and controlled, the internal factors are defined by the officers, stockholders or constitution of a corporation, as well as to external forces such as consumer groups, clients, and government regulations. A corporate governance perspective committed to ethical behaviours in business is very essential for business growth, the organization ethical operations and culture has been on the periphery of corporate governance and board leadership, linked mainly to corporate reputation. However, in today’s globalized and interconnected world, investors and other stakeholders have come to recognize that environmental, social, and governance based on the ethical responsibilities of a company as integral to its performance and long-term sustainability. Internal control procedures and policies implemented by an entity's board of directors must be in line with the values of the organization, audit committee, management, and other personnel to provide reasonable assurance of the entity in achieving its objectives related to reliable financial reporting, operating efficiency, and compliance with laws and regulations. Internal auditors in an organization should be able to test the design and implementation of the entity's internal control procedures and the reliability of its financial reporting. The global financial crisis has heightened the need for corporate boards of directors to provide well informed strategic direction and engage in oversight that stretches beyond short-term financial performance. Doing so prepares companies to more comprehensively address risks, by anticipating potentially adverse impacts on people and the environment and managing tangible and reputational risks. It can also generate wealth by creating shareholder value through an increase in business opportunities and broader access to markets. In recent years, corporate governance based on the ethical values has received increased attention because of high-profile scandals involving abuse of corporate power and, in some cases, alleged criminal activity by corporate officers. An integral part of an effective corporate governance regime includes provisions for civil or criminal prosecution of individuals who conduct unethical or illegal acts in the name of the enterprise.

There are many attempts to apply artificial neural networks in mechanical engineering field. In this work an attempt has been made to apply the artificial neural networks in the analysis of automotive tires. The study of tire performance and deformation are challenging owing to the non-linearity associated with geometry as well as composition of material. The tire material is a cord-rubber composite, its properties anisotropic in nature. The present attempt is to analyze the tire using artificial neural network. The tire deformation under various inflation pressures has been modeled by artificial neural network. To train the network, the experimental data has been used. It has been found that the artificial neural network can effectively be used in the analysis of pneumatic tires. The artificial neural network is employed to analyze the displacement of side wall of the tire for various pressures. The pressures are given as the input and the artificial neural network is trained with the displacement of ‘x’ and ‘y’ as the output target. The ultimate purpose of a finite element analysis is to create mathematical behaviour of an actual engineering system. In other words, the analysis must be an accurate mathematical model of a physical prototype. This model comprises all the nodes, element material properties, real constants, boundary conditions, and other features that are used to represent the physical system. In ANSYS terminology, the term model generation usually takes on the narrower nurturing of generating the nodes and elements that represent the spatial volume and connectivity of the actual system. Thus the model generation means the process of defining the geometric configuration of the model nodes and elements.