Engineering and Technology Journal

In this paper, the authors aim to introduce contamination in Al Tuwaitha nuclear
site, Iraq using GIS techniques and visual interpretation. This contamination problem
draws attention to the new result of high-radiation dose equivalents found in part of
the country. The radiation levels in Al Tuwaitha nuclear site, compared with the
international standards of UNSCEAR 2000 and world nuclear association (WNA
2011), the absorbed doses in the study area vary between (0.01-140) mrad/hr, in Al
Tuwaitha nuclear research center. The maximum radiation dose was nearby the
Russian 5 MW reactor. The absorbed dose in Russian 5 MW reactor was about (140)
mrad/hr which is the highest hotspot in Al Tuwaitha nuclear research center. The
obtained values of the average absorbed dose rate level are exceeding the permitted
level by (9500) times higher than environmental levels given by UNSCEAR (2000).

In order to produce a coating with suitable properties, many additives are included in a coating formulation to achieve specific property modifications .
In this work , two kinds of flame retardant materials were used as additives to increase the combustion resistance , and to decrease the flame spread of oil paint , these are : soluble Sodium Silicate and Sodium Silicate powder with oil paint. Different weight percent ratios (2.5 , 5 , 7.5 , 8.5 , 10 , 12.5 ,15 ) % for the two additives were added to oil paint to obtain different samples. It was found that , good flame retardant , and distinct decreasing in flame spread ( flame speed ) , of oil paint was obtained , in all weight percent ratios for all the samples of the two additives . Self extinguishing was observed at the ratios (7.5 , 8.5 , 10 , 12.5 ) % for the two additives , and ( no burning ) for them , were observed at (15) % . The mechanical properties tests ( adhesion force , impact strength ) were carried out to painted samples with oil paint mixed with second additive for all the above ratios, after about month from its preparation , the samples complied with Iraqi standard specifications No. 960 .

In this paper, the finite element analysis was carried out on boom of telescopic crane using ANSYS package software and the manual calculation as well as the analysis by the strength of materials procedure. The stress picture along the boom model was conducted under the maximum load carrying capacity. The stress developed at the interception of hydraulic rod with the first tube is higher than that developed along the rest of the boom. Moreover, the maximum deflection occurs at the boom head sheave.
In order to investigate the accuracy of the results, a comparison between the two approaches and the exact obtained by the strength of materials procedure is carried out.
Although the high capabilities of ANSYS software, the results are somewhat less accurate than that obtained by the manual calculations. Besides that, the results obtained by the finite element manual calculations are wholly similar to that of strength of materials procedure. Model taken for this paper is TADANO TR-350 XL 35-ton capacity.

This research presents the theoretical model, simulation and experimental verification of the maximum stepover estimation for different cases on the machine surface profile using the end-filleted cutter in multi-axis machining. Where in this research, the equations that detect the maximum stepover at allowable scallop height value have been taking into consideration and derived to predict the tool path generation for different inclination angles of tool axis. A set of inclination angles of cutter tool axis that can machine the workpiece have been taken into consideration depending on the shape of the workpiece. The inclination angle of the tool axis, effective cutter radius, and the geometrical shape of the workpiece have been studied and experimentally verified for milling operation. The results show that the proposed model for estimating stepover at constant scallop height can predict the tool path generation for machining sculpture surfaces using CNC multi-axis machine

The cure process of epoxy resin diglycidyl ether of bisphenol-A (DGEBA) with aromatic amine (m-PDA) as curing agent was studied by means of differential scanning calorimetry (DSC) Perkin Elmer Pyris 6, at ratio (15 phr). Isothermal DSC measurements were conducted between 80 and 110 oC, at 10 oC intervals. The maximum degree of cure at isothermal cure temperature 110 oC was 0.9. The isothermal cure process was simulated with Kamal modifier with diffusion model, the model agrees well with the experimental data. For dynamic cure process, the activation energy was determined by two methods. One was based on Kissinger and Ozawa approach, given only one activation energy for the whole curing process. There was a slightly difference between the obtained activation energy and pre-exponential factor, 63.6 and 70.7 kJ mol-1 respectively. Another method was based on isoconversional, given activation energy at any conversion, and observed the Ea decrease with increment conversion (67-63) KJ/mol

Future wireless communication systems must be able to accommodate a large number of users and simultaneously to provide the high data rates at the required quality of service. In this paper a method is proposed to perform the N-Discrete Hartley Transform (N-DHT) mapper, which are equivalent to 4-Quadrature Amplitude Modulation (QAM), 16-QAM, 64-QAM, 256-QAM, … etc. in spectral efficiency. The N-DHT mapper is chosen in the Multi Carrier Code Division Multiple Access (MC-CDMA) structure to serve as a data mapper instead of the conventional data mapping techniques like QPSK and QAM schemes. The proposed system is simulated using MATLAB and compared with conventional MC-CDMA for Additive White Gaussian Noise, flat, and multi-path selective fading channels. Simulation results are provided to demonstrate that the proposed system improves the BER performance and reduce the constellation energy as compared with the conventional system.

A simple computational model is established to simulate the spark gap discharge phase. The proposed computational approach is based on Rompe- Weizel model for the resistive phase of the spark discharge where the plasma resistance decreases dramatically and rapidly during this phase converting the gap from a non-conducting (off) state to a conducting (on) state . Results obtained from this model are compared with some available published data and acceptable agreements are obtained

The main objective of the research is to find the optimum parameters that
reduce the springback by using the commercially [SPSS] program to analysis data
and find the best parameters which given lowest springback in the U-die bending.
A commercial aluminum alloy [AL-1050] sheet (0.9 mm) thickness that founded
when punch speed increase the springback increase, when rolling direction angle is
90 Lower springback, and when increase the dwell time decrease the springback,
and the value of parameters predicted from [SPSS] have lower springback and
obtain a goal dimension for the products. And predict the springback value by
especial equations which given correlation coefficient 95.4% between the observed
value of the dependent variable and the predicted value.

In this paper, the seepage analysis through and underneath the hydraulic structures is studied at the same time without dividing the structure into parts, and then analyze each part individually. The analysis has been done using the finite volume method using rectangular elements. This method implemented on several types of structures and the comparison of the results is made with the one solved using finite element method. The comparison showed close results. The finite volume method has been implemented on non-rectangular structures. The present work studied the effect of heterogeneous foundations on the uplift pressure and exit gradients at the downstream and comparison with homogenous foundations. Also it studied the evaluation of effect of position and inclination of cut-offs at upstream or downstream of structures on uplift pressure and exit gradients at downstream. In addition, it studied the effect of impervious body inside the structure or foundation on uplift pressure and exit gradients at downstream.

This study describes a three-dimensional nonlinear finite element model suitable for the analysis of high strength reinforced concrete arched beams under static load. The twenty node isoperimetric brick element has been used to model the concrete and reinforcing steel bars have been idealized as axial members embedded within the brick elements. Perfect bond was assumed to occur between the concrete and the reinforcing bars. The behavior of concrete in compression is simulated by an elasto-plastic work hardening model followed by a perfectly plastic response, which is terminated at the onset of the crushing. In tension, a smeared crack model with fixed orthogonal cracks has been used. High and normal strength reinforced concrete arched beams have been analyzed in the present study. Parametric studies have been carried out to investigate the effect of radius to span
length ratio, boundary conditions, (α2) [the sudden loss of stress at the instant of cracking], and effect of compressive strength. In general good agreement between the finite element solutions and the experimental results have been obtained.

In this paper two cameras have been used to determined the interior orientation parameters (IOP) for each camera. To carry out the calibration, Photomodeler Scanner software was used. The lab calibration process was completely automatic using a calibration grid. The focal length was fixed at narrowest and widest angle and the network includes a total of twelve images with ± 90º roll angles. Each zoom was calibrated for five times. After the software processing, the camera calibration parameter values were obtained.The paper presents the results and the accuracy of this calibration method, Furthermore the overall RMSs obtained from the calibration for both cameras are in micron but calibration cannot be considered as constant or fixed for non-metric cameras, because such cameras have different (IOP) for each capture

Analytical solution have to obtained of contact problem for indentation of flat punch with rounded edges in axi symmetric extrusion to both surface pressure and interior stress fields for a given die shape at different velocity fields. Both sliding friction and partial slip condition must be concluded in the equation of metal flow for extruded material taking into consideration von Mises yield criterion and the complicated high elastic contact stress in the flat and rounded edges dies. An experimental method using prototype sample of photo elastic material to determine the effect of rounded edges on the stress distribution in the contact zone. A numerical method used programming for solving the analytical equations of metal flow using quick basic and comparing the theoretical with the experimental results .A kinematically admissible metal flow cylindrical velocity using strain rate of plastic flow has been proposed to obtain the load of contact on the elastic punch face during the axi-symmetric backward extrusion. The theoretical results predict the forming force , rule of friction , area reduction and the metal flow quite satisfactorily when compared with the experimental results.

Hard decision of Viterbi decoder suffer from the need of high Signal to Noise Ratio (SNR) to achieve reasonable Bit Error Rate (BER). For the purpose of improving the efficiency of its performance, it must increase the constraint length of the code, in this case highlights the problem of complexity in the structure. Several methods are used to solve this problem. In this paper the Log-Likelihood Ratio (LLR) with 3 bit soft decision and unquantized scheme has been implemented with simple transceiver using Convolutional codes. Results are achieved using the last version of Matlab (R2011b) illustrates that such scheme 2.7 dB over conventional system. In addition it has been examine such system with increasing the speed of data rate to double, the results of simulation confirm that it need 7 dB to achieve 10-6 BER

This paper deals with the results of an experimental study carried out on compacted clayey soil, to investigate the strength and consolidation characteristics of this soil. This soil having special case of standard compaction curve contain two values of maximum dry unit weight and two values of optimum moisture content between these point minimum dry unit weight was occurred.
The results show that the maximum compressive and tensile strength lies on point near the point of second peak on standard compaction curve. Also the maximum bearing capacity and minimum settlement at the same point on standards compaction curve. Finally the preferred zone to conducted the compaction in field at this point where the dry unit weight at this point was 16.5kN/m3 while the moisture content was 18%.

Heat transfer augmentation due to twisting parameter was investigated in atwisted tube of square cross sectional area. Twisting parameter is defined as the ratio of the length of the tube where it completed twisting of360 degrees to its hydraulic diameter.
Four twist parameters were chosen;5, 10, 25 and 50, and a comparison is made with a straight untwisted duct.
Two sets of Reynolds numbers were considered for laminar and transient flow. The laminar flow is performed at . While for transient flow the range of Reynolds number are and .Theinfluence of twist parameter on convective heat transfer coefficient in laminar and transient flow was investigated.
Numerical simulations were performed for three-dimensional, steady state incompressible flow in body-fitted coordinate using finite volume method and standard turbulence model. For the heat transfer problem the uniform wall temperature (UWT) boundary condition at tube wall is considered.
It was observed that the heat transfer coefficient increases with decreasing twist parameter. This is interpreted to the nature of span wise swirling flow generated. The swirling increases cross flow velocity vectors as it becomes far from tube center towards walls. At tube wall the thickness of boundary layer becomes thinner as near wall velocity become larger which leads to a boundary layer of good thermal characteristics. Also swirling increases internal mixing process which enhances internal thermal equilibrium. The heat transfer coefficient also increases as Reynolds number increased as velocity components are increased