Physical Sciences and Engineering

In the recent years utilization of polymeric materials increased due to their good mechanical properties and easy manufacturing. Starting from automotive industry up to food industry polymeric materials are used for obtaining components by molding or by machining. Taking into account the wide range of applications, it is important to know the mechanical behavior of the materials in different loading conditions. Rapid Prototyping Techniques (RPT) are widely used to produce objects with good dimensional accuracy, surface roughness and material strength by adding the material layer by layer.

At present, bad debt has become a stubborn enemy of financial industry in every country. So there arises a need of a technique which will identify the risk in loan approval. Fuzzy logic is a computing model which deals with uncertainty rather than the traditional True (1) and False (0) values and has caught some eyes in recent years. Fuzzy logic is a valid and novel means of problem solving with intelligent systems which deals with imprecision, vagueness and uncertainty in the financial applications like loan processing.

This paper describes the evaluation of the wave profile of submarine at surface condition and deck flooding which occurred by the wave making pattern at the bow. Movement of ships and submarines on the free surface of calm water creates the surface wave. Because of the difference in the bow shape and freeboard height, the wave making system in ships and submarines is different. Rounded or elliptical bow shape of submarines generates a high bow wave which causes deck and bow wetness. This is because of the fact that, in submarines this situation arises a small freeboard.

This study aimed at finding out the perceptions of secondary school mathematics teachers who had attended in-service training under Secondary Science Mathematics Teachers’ programme. A mixed methods approach was used in this study and data was collected using a survey questionnaire and focus group discussion. Findings from this study indicate that most teachers perceive the programme to have positively impacted on their teaching skills i.e. towards the implementation of the main objectives of SESMAT in-service training.

Vehicular ad hoc networks (VANETs) are a special form of wireless networks made by vehicles communicating among themselves on roads which includes communications among vehicles and between vehicles and road side units. However, due to the high mobility and the frequent changes of the network topology, the communication links are highly vulnerable to disconnection in VANETs. This paper extend the well-known ad hoc on-demand distance vector (AODV) routing protocol with evolving graph theory to propose reliable routing protocol EG-RAODV.

Des échantillons de Pb(X0.20,Ti0.80)O3 (X= Lanthane, Magnésium, Manganèse, Calcium, Cuivre, Bismuth et Vanadium) ont été élaborés par la voie solide conventionnelle. Les températures de calcination, pour les différents échantillons élaborés, ont été choisies dans l’intervalle [800 °C, 900 °C]. La durée de calcination a été de 4 heures. La caractérisation par spectroscopie de diffraction des rayons X montre l’effet de l’élément dopant sur la phase cristalline, la température de calcination et la taille des cristallites des poudres fines élaborées.

Ceramic powders of lead titanate, co- doped with copper (Pb0.9Cu0.1TiO3) and cobalt or zinc, of a perovskite structure were prepared by the sol-gel process by adopting the mode of the destabilization of colloidal solution. The effect of temperature and dopants on the structure of the obtained samples was studied by X-ray diffraction (RX), Raman spectroscopy and scanning electron microscopy (SEM). Analysis of the samples with fluorescence spectroscopy shows that Zn simultaneously occupies the sites A (Cu) and B (Ti) of the structure, creating oxygen vacancies.

Multilevel inverter is a very popular in various fields like FACTS devices,HVDC systems, industrial drives,photovoltaic systems etc. It has a large number of advantages like low stress on switches,lower harmonics,low switching losses etc. There are different topologies available like neutral point or diode clamped inverter, flying capacitor inverter etc. each having numerous disadvantages and advantages. The efficiency of this inverter is greatly improved by minimising the number of switches of the configuration used.

Let G = (V,E) be a graph with p vertices and q edges. A Extended Mean Cordial Labeling of a Graph G with vertex set V is a bijection from V to {0, 1,2} such that each edge uv is assigned the label ( (⌈f(u)+f(v))⌉)⁄2 where ⌈ x ⌉ is the least integer greater than or equal to x with the condition that the number of vertices labeled with 0 and the number of vertices labeled with 1 differ by at most 1 and the number of edges labeled with 0 and the number of edges labeled with 1 differ by at most 1. The graph that admits a Extended Mean Cordial Labeling is called Extended Mean Cordial Graph.

This study demonstrates the efficiency of the multi-component induction tool (3DEX) that simultaneously measures the vertical and horizontal resistivity of the formation, by presenting a comparative petrophysical evaluation of thinly bedded reservoirs using Conventional logs and 3DEX data acquired from two different fields of which one is an oil-bearing reservoir formation from Olu field in the Niger Delta province and the other is a gas-bearing reservoir formation from Balda field in North Sea.