Journal of Engineering and Sustainable Development (JEASD)

novel approach for identifying friend aircrafts from foe (IFF) using public-key cryptosystem is introduced. Tow schemes of public-key cryptosystem which provide higher security than convention(IFF) are presented computer simulation examples are also included to illustrate the identification procedure.

In this paper a composite beam element has been developed in this study, the composite beam element can be used to model the nonlinear behavior of composite beams. The element is implemented in a nonlinear finite element program (written by the researchers) and its implementation is verified by the analysis of simply supported composite beam tested by others. A good comparison between the computed results and the experimental data demonstrates the accuracy of the used element.
It was found that the increase in cover plate thickness gives an increase in the ultimate load and a decrease in a maximum slip at the same load level.

This investigation deals with the estimation of bubble growth rate during nucleate pool boiling of pure liquids and miscible wide boiling range binary mixture such as n-Pentane/Tetradecene mixture. Understanding the process of heat exchange between the heating surface and the adjacent liquid during boiling should start from the ability to understand the mechanism of bubble growth rate and departure parameters (diameter and frequency). For binary mixtures, the mass balance of the more volatile component (n-Pentane) and energy balance at the vapor/liquid interface were used to predict the bubble radius, R(t), as a function of time. Whereas, for pure liquids the energy balance at the bubble boundary was used to estimate the bubble radius together with the temperature distribution in the liquid domain. The bubble growth rate of binary mixtures predicted by this model was compared with existing
theories. The discrepancy in the bubble growth constant between this analysis and those of other investigators was explained and verified by the present model. The model of pure liquids showed well agreement with available experimental data.

This research is carried out to evaluate the amount of bed sediment load entering Haditha reservoir. The proper selection of a sediment transport formula to evaluate river\'s response is important. However, there are no definitive guidelines for the selection of transport formula. Therefore, an analysis was made on six sediment transport formulas, (Engelund-Hansen, Ackers-White, Yang, Maddock, Graf-Acaroglu and Karim-Kennedy) to check the applicability of each transport formula. The data used have been investigated by depth-integrated sampling over a period from 26/1/2003 to 10/3/2003 and from 15/6/2003 to 16/9/2003. Besides, a new formula was developed as sediment transport predictor for expected ranges of hydraulic and sediment characteristics of Euphrates river up-stream of Haditha dam. It was concluded from the analyses that the used six formulas required adjustments to closely describe the measured data. Engelund-Hansen and Maddock formulas are better than other four formulas in predicting the total sediment load.

In this work, the enthalpy potential theory is used in conjunction with a formula derived by Uchida and a set of data available on the cooling tower of Baghdad international airport to predict the thermal performance of a mechanical draft counter flow cooling tower of closed type.Computer calculations are made to determine the number of transfer units, water-cooling range and tower capacity. The computer results are presented in graphical form as performance curves showing the predictable thermal performance of the tower under different conditions of air inlet wet bulb temperature and water-to-air flow ratio, when the load on the tower, denoted by the water inlet temperature, remains unchanged. The results indicated that the performance of the tower and hence its capacity are affected by the air inlet wet bulb temperature and the water-to-air flow ratio. They face a considerable decline with increase of air inlet wet bulb temperature and with increase of water-to-air flow ratio too. Then, the decline with increase of air inlet wet bulb temperature reduces with increase of water-to-air flow ratio. The agreement of the present results with results of the others and with measurement would give a sufficient support to the analysis adopted in this work.

This work is intended to evaluate the flexural and cracking behavior of both Dense and Gap graded Asphalt concrete. Slab samples of 30×30×7cm size have been constructed in the laboratory using the TRRL roller wheel compactor. Various Asphalt percentages were adopted.Beams were sawed from the slabs at two different positions (parallel and perpendicular to rolling direction). Beams were tested for flexural strength at 8˚C and the load-deformation relationships were obtained. The flexural modulus, the stiffness and E- Modulus were determined. The deflection and cracking of beams were observed and the various modes of displacement were studied. It was concluded that rolling direction has a significant effect on fracture strength for both Dense and Gap graded Asphalt Concrete; The predicted displacement of beams with Gap gradation were higher especially at high Asphalt content when compared to Dense mixes while the variation of measured displacement between Dense and Gap mixes is not significant. E- Modulus of dense mixes was higher at various Asphalt percentages. On the other hand, the variation of both flexural and stiffness modulus at optimum Asphalt content was not significant for all of the mixes studied.

One of the problems that face the designer in the cooling load calculation in Iraq is the usage of CLTD-CF or TETD method. The problem is the difficulty in finding a roof in the tables like the roofs that are used in our buildings in Iraq. This paper is focused on the problem and analyzing the temperature distribution across the roof. The analysis uses the explicit Finite Difference method to find the temperature gradient and the cooling load for a building in June and July. To check the validity of the computer program, a measurement of the roof surface temperature has been made which gives very good agreement.

his study includes a series of pullout tests which contain fifty four specimens with short bonded length (5db) to study the effect of many variables on bond strength for normal and high strength concrete. The variables are: (bar diameter, concrete compressive strength and cover). The study also studies the effect of each variable on bond strength, and suggests two equations to link bond strength with the variables mentioned above. The test results show that, the bond strength increases with the increase of compressive strength and/or cover and decreases with the increase of bar diameter and vice versa. Also, the test results obviously show that, increasing compressive strength reduces the need for cover, where with the increase of the compressive strength from 20 MPa to 75 MPa, the need for cover reduces by34% for the same bar diameter depending on nonlinear regression analysis for the resultant of experimental work, two equations are suggested in this study, the first links the variables (bar diameter, concrete compressive strength and cover) with bond strength where the value of (R) is 0.923. While the second equation links the ultimate bond strength with the variables mentioned above where the value of (R) is 0.927.

Experimental results are presented for the preparation of an electrode to replace platinum in the perchlorate cell. Compact anode of multi-layer lead dioxide on titanium (TSLD) anode has been developed for obtaining a suitable anode size of geometrical electrode shape and type of joining and assembling within the electrochemical cell. This can be considered as a feeding behavior by D.C. current and the suitable quantity of anode electrode to apply cell electrolysis of perchlorate production of high current application.Current-potential curves of the electrolytic oxidation of chlorate were determined. The polarogram obtained has two potential stages; the lower one is the potential of oxygen evaluation and the higher one is the potential of perchlorate formation which is less than that reported for the platinum anode by 0.3 V.The prepared TSLD anode has been used successfully in the presence of certain additive (NaF), as a replacement for platinum anode in sodium perchlorate preparation experiments.

Two specimens of pure aluminum, deformed by 4% were cut in “Trapezoidal Strip” shapes. The first specimen was heated by D.C current with a current density of up to 4500 Amp/cm2 and for a duration of 8 hours, whereby the temperature had risen up to 590 oC at the top of the specimen, and up to 4505C at the regions near the two terminals of the specimen, the recrystallization process appeared with different grain sizes (g.s), which was 2.5mm on the top region of specimen, and 1.5mm, 1.3 mm on the Cathode and anode terminal respectively. This difference in g.s was due to the appearance of ionic accumulation on the grain boundaries (g.b) only at the anode terminal. The second specimen was also heated in a normal furnace at 450oC for 8 hours, then the recrystallization process was seen with the same (g.s) on both terminals of the specimen, and there was no ionic accumulation found in any part of this specimen. This study indicated that the effect of D.C caused the presence of ionic accumulation which took place on the (g.b) as half-spherical caps at regions near the anodic terminal of the first specimen. This caused the difference in (g.s) at both terminals in the first specimen.