This paper presents a through investigation into the effect of the external antenna and printed circuit board (PCB) positions in cellular hand-sets on the coupling between the handset and human-head at GSM-900 frequency standard. The antenna performance and the specific absorption rate (SAR) induced in a human head were computed using a Finite Difference Time-Domain based platform (SEMCAD). A numerical correct model of a European female head was adopted and a semi-realistic hand model was designed during the simulation. The results showed that the optimum position for the antenna and PCB in hand-set close to head is the far right-corner for the right-hand users and the far left-corner for the left-hand users, where a minimum SAR in head is achieved.

This research is devoted to investigate the effect of structural geometry on the crushing behaviour, energy absorption, failure mechanism, and failure mode of radial corrugated composite shells. A multi-discipline literature review on the use of composite materials in the field of crashworthiness was carried out. Based on the literature review findings, new composite structure (Radial Corrugated Composite Tube RCCT) was proposed to be fabricated and investigated experimentally.

In this article an investigation was conducted to evaluate the level of conformity of reinforcing steel rods produced from recycled scraps by Zliten Steel Factory (ZSF) with relevant to Libyan specifications and international standards. A series of experimental tests were conducted to find ultimate tensile strength (UTS), yield strength (YS), and hardness. Bending test has been conducted too. Reinforcing steel rods samples of 12 and 14 mm diameter were subjected to mechanical properties investigations. The tests were carried out for samples selected randomly through three batches at different time. Obtained results were compared with Libyan specifications (LNS-75) and ASTM standard (A-615). Results showed that the locally produced reinforcing steel were conform with the Libyan and international standards in terms of yield stress, ultimate tensile stress, and hardness.

Abstract:

A detailed experimental investigation of the quasi-static lateral crushing of composite cylindrical tubes between flat platens has been carried out. Tubes employed were made of glass fibre reinforced with epoxy. Behaviour of tubes as regards the peak crushing load, post collapse load, energy absorbed and mode of crushing has been discussed. The load displacement response is plotted graphically.

Many questions enter our minds, which may take us to another world. However, this is a very brief paper about cosmology and its relation with man and culture with particular reference to reflection in built-form. It can be seen as an approach to amalgamate many subjects.

Abstract

This paper is devoted to study the effect of corrugation geometry on the crushing behavior, energy absorption, failure mechanism, and failure mode of woven roving glass fibre/epoxy laminated composite tubes. A comprehensive experimental program has been carried out on two geometrically different types of composite tubes subjected to axial compressive loading conditions. A cylindrical composite tube has been fabricated and tested in order to provide a means of comparison with corrugated composite tube. Both are tested under the same condition to establish the effect of corrugation geometry. The results showed that the initial failure was dominated by interfacial failure, while a folded zone grows progressively down in a form of mushrooming failure. The results also showed that radial corrugated composite tube (RCCT) exhibited good energy absorption capability than circular composite tube (CCT).

Abstract: The purpose of this work is to investigate the effect of the dimensions of composite tubes on their specific energy absorption capacity. Experimental investigations were carried out on three geometrical different cylindrical composite tubes subjected to compressive loading. More over a radial corrugated composite tube was subjected to the same load conditions in order to examine the varying of shape influence on the energy absorption of composite materials. Initial results indicate that for cylindrical tubes, diameter to thickness ratio has a significant effect on the energy absorption. Reduction in tube d/t ratio results in an increase in energy absorption. More over results show also radial corrugated composite tubes exhibit higher total energy absorption than cylindrical composite tubes. 

Experiments were performed to investigate the diffusion ignition process that occurs when hot inert gas (argon or nitrogen) is injected into the stoichiometric hydrogen-oxygen mixture at the test section. Detonation wave initiated by spark plug in the driver section in stoichiometric acetylene-oxygen mixture at P = 0.5 MPa and room temperature, propagates as incident shock wave in the driven section through inert gas after bursting the diaphragm separating the sections. At the end wall of driver section the inert gas is heated behind the reflected shock wave and then injected into the test section with the stoichiometric hydrogen-oxygen mixture through the hole 8 mm in diameter. An increase of the initial pressure of the combustible mixture in the test section from 0.2 to 0.6 MPa resulted in decrease of the minimum temperature of injected gas causing ignition from 1650 K to 850 K. At the same time the induction time for ignition process has increased from 190 to 320 s when hot argon was injected. For the injection of hot nitrogen an increase of the initial pressure of the combustible mixture from 0.2 to 0.4 MPa resulted in decrease of the minimum temperature of injected inert gas giving ignition from 1150 K to 850 K, and in increase of the induction time from 170 to 240 s. The results of experiments indicate that ignition occurs when the static enthalpy of injected mass of inert gas exceeds some critical value. The mechanism of ignition process was also studied by schlieren photography.

Abstract

           This paper presents the effect of corrugation geometry on the crushing behavior, energy absorption, failure mechanism, and failure mode of woven roving glass fibre/ epoxy laminated composite tube. Experimental investigations were carried out on three geometrical different types of composite tubes subjected to compressive loading. On the addition to a radial corrugated composite tube, cylindrical composite tube, and corrugated surrounded by cylindrical tube were fabricated and tested under the same condition in order to know the effect of corrugation geometry. 

This research presents the effect of radial corrugation geometry on the crushing behavior, energy absorption, failure mechanism, and failure mode of woven roving glass fibre/ epoxy laminated composite tube. Experimental investigations were carried out on three geometrical different types of composite tubes subjected to compressive loading. On the addition to a radial corrugated composite tube, cylindrical composite tube, and corrugated surrounded by cylindrical tube were fabricated and tested under the same condition in order to know the effect of corrugation geometry.