Journal of Engineering and Sustainable Development (JEASD)

An analytical model for the calculation of long term deflections of reinforced concrete two way slab, flat slab and flat plate floor systems is proposed in this paper.The proposed analytical model takes into account the significant factors influencing long-term slab deflections. It follows the short term deflection calculation methods with realization of the time dependent effects on the flexural rigidity of slabs.The calculated deflections using the proposed model are compared with several field measured deflections and show good agreement with them.

Fading problem is a major impairment of the wireless communication channel. In this paper we considers different diversity techniques to mitigate the fading problem in wireless channel for DS CDMA (Direct sequence Code Division Multiple Access) system.
Diversity is an effective method for increasing the received signal-to-noise ratio of a wireless communication system in a flat Rayleigh fading channel. Diversity branches can be established through frequency, time, antenna, or any combination of these diversity mechanisms.
The branch outputs can be processed using schemes such as selection combining, equal gain combining, or maximal ratio combining. The diversity combining technique used in this paper improved the performance of the DS CDMA system. For this system, three spreading code sequences are used to spread the spectrum of the signal namely, an M-sequence, a Gold sequence, and an Orthogonal Gold sequence. The BER performance in a two path flat Raleigh fading environment for DS CDMA system with diversity combining is evaluated using MATLAB 7 computer simulation software

The aim of this study is to investigate of the capability of ultrasonic technique in assessment of the filler content effects in polymer matrix composite and to provide additional data concerning the particulars of the use ultrasonic response, velocity and attenuation measurements for quality control and sorting composite materials. For the experiments, filled acrylic (matrix) with different weight percentages of calcium silicate and carbon black powder (fillers) individually were moulded. The pulse-echo amplitude technique and normal probes of (1, 2 & 4 MHz) was used. The directional dependence of velocity, attenuation, hardness and filler content were investigated. Also the ultrasonic measurements were carried out at various testing frequencies to observe the reliability of the technique employed. Both filler type and filler weight (%) were systematically varied to investigate their effects on the ultrasonic response of thermoplastic acrylic (PMMA). It was observed that, in general, as the filler weight (%) increased, there is decay in the ultrasonic response provided particles dispersion and deagglomeration was maintained. Increase of filler weight (%) also accompanied by increase in the ultrasonic attenuation and reduction in ultrasonic velocity and hardness. Clear correlation between these measurements was obtained beyond (15%) filler weight percent. It was concluded that ultrasonic technique are sensitive to the filler content in composite materials. Because the....

Quantum cryptography is anew branch of physics and cryptography which exploit quantum mechanical phenomena to guarantee the secrecy of cryptographic keys. This paper introduces the basic concepts, problems and methods of quantum key distribution. It introduces some basic knowledge of quantum mechanics and explains how these physical laws can be used in cryptography. The basic protocols of quantum cryptographic used for key distribution based on entangled polarization photons pair are also presented and assessed. The well known concepts based on entangled pairs of photons (Ekert) schemes are presented. In these schemes Alice and Bob perform measurements on each photon along one of two, three or four directions given by unit vectors and (i, j = 1, 2, 3,4) respectively. Therefore the combinations are used from Alice and Bob is four, nine, or sixteen with respect to number of measurement directions (i = 2, 3 or 4) respectively. The analysis and comparative study between these versions are presented

In this study, the effect of fire on the compressive strength of high strength concrete (HSC) is investigated. Two different tests, one of them is the non destructive test which is the ultrasonic pulse velocity (UPV) test and the other is the destructive compression test, are carried out using (10cm) cubes. Forty-five cubes (one third of them are of normal strength concrete (NSC) with original strength of (52.67 MPa) and the other two thirds are of (HSC) with original strength of (61.04 and 72.33 MPa), respectively, are heated to temperature levels of (200, 400, 600, and 800°C). Then after specimens are air cooled and (UPV) test is done, the specimens are destructively tested. The results indicated that, the residual compressive strength after high temperature exposure of the (NSC) is higher than that of (HSC),for example, the residual compressive strength after exposure to temperature level (800°C) for the former is (39.5%) while for the later is(19.5%) at worst case from their original strength. Also, the compressive strength reaches its peak value in the (NSC) earlier than the (HSC). Statistical analysis is made to find mathematical relationships to relate the results of the destructive test with that of non destructive test for both the (NSC) and (HSC), also to relate the results of (HSC) with that of (NSC).

It is generally accepted that normal pressure beneath a track laying vehicle has great influence on the slip and the tractive effort developed by the vehicle. However, and for simplicity, most of the previous works assume uniform pressure underneath the track. Consequently values of experimental results were quiet different from those of the predicted theoretical values.
In this paper, emphasizes have been directed towards proper selection of vehicle configuration which is of almost importance. So, and as a result , different types of normal pressure underneath the track have been analyzed, ranging from constant , to uniform sinusoidal, and then to non uniform values. The magnitudes of drawbar pull for each type of pressure distribution on soft ground were evaluated theoretically with the aid of computer, using (''MATLAB'' package). The aim is to obtain the best value of draw-bar pull among these pressure distributions, thus achieving the optimum design criteria

This paper focuses on the antenna synthesis of uniformly spaced linear phase array using artificial neural network (ANN), and describes the basics of artificial neural network. Chebyshev method is used to compare with this approach. Although, Chebyshev method is able to generate perfectly leveled side lobes, ANN does not have the phenomena of up-swing in edges amplitude of the excitation and grating lobes does not appear in ANN when the distances between elements are increased.
The basic rule is to alter the weights (current distributions of elements) such that the error between the output values and the target values (desired values) is minimized.
In this paper, single layer feed forward neural network with supervised learning is used. An adaptive linear element algorithm (ADALINE) is used for training artificial neural network

The effect of exposure to elevated temperatures up to (500 oC) on shear transfer strength of concrete was investigated experimentally in this study using push-off specimens. Three groups of specimens were used, each of four specimens. One specimen from each group was heated to (150 oC), the second specimen was heated to (350 oC) and the third specimen was heated to (500 oC), while one specimen from each group was tested without heating as a reference specimen. The three groups of specimens differed from each others by the amount of shear reinforcement crossing the shear plane.The test results of this study showed that shear transfer strength decreased by about (18% to 42%) and that the higher shear reinforcement specimens retained higher strength values than those of lower shear reinforcement ones after exposure to all the studied temperatures. Also, a comparison was made between the post heat exposure behavior of shear transfer strength and the compressive and tensile strengths of concrete. It was observed that the behavior of shear transfer strength of concrete after high temperature exposure can be closely related to compressive strength than splitting tensile strength.

A polyester and composite polyester thin plate have been tested under a certain constant distributed load (q=8N/mm2) so as to give a linear behavior over the plane of area at constant temperature (T=15ºC). The plate has been tested for thickness values (t=2,3,4mm). The type of boundary condition used here is two sides are fixed and the other two sides are simply supported. For the linear behavior of the polymer, a linear finite element program is achieved with the aid of FORTRAN power station program. The results of the FEM, theoretical and the experimental were compared. A good accuracy has been observed between the FEM, theoretical and the experimental work. In general the deflection behavior depends on the creep compliance. Increasing thickness results in decreasing the deflection, this decreasing depend on the value of thickness increasing. The deflection rate decrease during time for polyester, which depend on the creep function. The increasing in the plate dimensions ratio results in increasing the plate surface deflection for both plates (polyester and composite polyester plate). A composite plate shows a small increasing in the deflection during increasing the plate dimension ratio as comparing with that of polyester.

The effect of changing impulsivity of noise and different relative power of impulsive noise are investigated and are compared with Additive Whit Gaussian Noise (AWGN) case. Also the performance of the OFDM receiver with blanking nonlinearity in the presence of impulsive noise will be studied.
Closed form analytical expressions for the signal-to-noise ratio (SNR) at the output of blanking nonlinearity and the optimal blanking threshold that maximizes SNR are derived.

In this research a computerized fault data collection and analysis system has been developed. The system described is called Computer Aided Failure Mode and Effects Analysis (CAFMEA).

This paper studies the shear capacity of normal strength concrete (NSC) reinforced beams with and without web reinforcement, as indicated by available research and explain the effect of beam size on shear strength of reinforced concrete beams. Two equations are proposed for design which is simple to use, safe and have low coefficient of variation (COV) when used for NSC.The results of analysis for NSC indicate that the proposed equations are conservative and give lower COV and smaller range of results when compared with the available methods of design which are based on the ACI.318M-02 [1], Canadian [2], B.S.8110-97 [3], New Zealand [4] codes and one equation proposed by Zsutty [5].By applying regression analysis was applied to both types of beams, with and without web reinforcement, two design shear equations are proposed, one for each type of beam.The computer programs which are used for this purpose are (QBASIC, Graph Win, and SPSS).

This investigation deals with the performance prediction of air conditioning unit. Theoretical and experimental studies were conducted to simulate the performance of vapor compression refrigeration cycle, using R-22 as a circulating refrigerant. The experimental work was carried out on an available air cooling unit which allows variation of different parameters such as air dry bulb temperature, flow rate and humidity affecting the operation conditions of the unit. The comparison between the predicted and experimental data of (COP), cooling load, compressor work and condenser load showed a very good agreement. Also a detailed design of finned tube evaporator heat exchanger coil in air conditioning unit was developed. Here, the vaporization and superheating portions of heat exchanger have been modeled separately to predict the exit air condition, dry bulb temperature and humidity content, at the leaving section of the cooling coil. The evaporator mathematical model showed a well agreement with the experimental data of this research.