Al-Nahrain Journal for Engineering Sciences

Commercial purity iron powders were produced by using a new hydrometallurgy process. It was found that the most important factor in enhancing the purity of iron was the number of water washing process. X-ray diffraction pattern showed that the high peak purity of iron powder increased with increasing the number of water washing. The developed new methodology was based on the reaction between the aqueous ferrous sulfate and the hydrochloric acid with the presence of high purity aluminum flake. The purity of iron powders increased considerably with increasing the multi-water washing for leachate containing iron powders. The purity of iron powders was reached up to approximately 93.5%. The mean particle size distribution and apparent density for the highest value of purity are 50-100 µm and 2.85 g/cm3 respectively

The experimental results showed increasing in ultimate load capacity and higher chlorides resisting for hybrid reactive powder concrete in comparison with normal concrete in both types of curing (tap and chloride water). Through studying load deflection, test results for Normal Strength Concrete (NSC) and Hybrid Fiber Reactive Powder Concrete (HFRPC) columns that deflection for columns cured in chloride water more than tap water when compared at the same load that also by increase eccentricity leads to an increase in deflection for both cured and The neutral axis depth for HFRPC columns is more than NSC at the same load also when eccentricity increases, the compression zone decreases and neutral axis also decrease by increase eccentricity. These results occur when columns are cured in tap and chloride water.

Free Space Optics (FSO) plays a vital role in modern wireless communications due to its advantages over fiber optics and RF techniques where a transmission of huge bandwidth and access to remote places become possible.
The specific aim of this research is to analyze the Bit-Error Rate (BER) for FSO communication system when the signal is sent the over medium of turbulence channel, where the fading channel is described by the Gamma-Gamma model. The signal quality is improved by using Optical Space-Time Block- Code (OSTBC) and then the BER will be reduced. Optical 2×2 Alamouti scheme required 14 dB bit energy to noise ratio (Eb/N0) at 10-5 bit error rate (BER) which gives 3.5 dB gain as compared to no diversity scheme.
The results show that using Multiple-Input-Multiple-Output (MIMO) technique represented by Alamouti scheme gives the improved BER performance as compared with no diversity (Single-Input-Single-Output (SISO)) technique.

The main idea behind this paper is to design and implement a cheap, smaller size, easily operable, easy interface and flexible 3-axis Computer Numerical Control (CNC) plotter machine. The lower cost is achieved by using 2 CD drives from old PC’s with their stepper motors as the main structure for the hardware. The two stepper motors already found in the CD drives used to control the pen movements onto X and Y axis and one servo motor on the Z axis. An Arduino Uno microcontroller is used to controls the proper synchronization of these three motors during printing/drawing process. The Arduino Uno is programmed with G-Code parser from PC that is connected to the Arduino via a USB cable to control the motors movement and synchronization. The plotter machine is implemented and tested by printed different images and texts on papers (8cm × 8cm) using a pen, the small size of the papers because of the small plotter size. The motors winding voltages were displayed on the oscilloscope during the printing process to investigate the synchronization between the three motors. The design of the circuit is simple, inexpensive and can be accomplished using commercially available components.

In this study, the analytic model (Azmi Model) had been considered for computation the load capacities of the composite open web steel joists and compared them with those obtained from experimental tests. The capacities of seven joists had been studied, each including one of the following variables (distribution of headed studs, connection degree of the connectors, inclination of the web, shape of the web, density of slab concrete, length of connectors).Theoretically, according to the Analytic model, the referenced joist of (45° web inclination , uniformly distributed ,over connected ,short headed studs) exhibited maximum load capacity of (18.45) ton, while the joist of (45° web inclination, uniformly distributed, under connected, short headed studs) exhibited minimum load capacity of (16.23) ton at yield point of bottom chord. Experimentally, the referenced joist exhibited maximum load capacity of (15.51) ton, while the joist of (34° web inclination, uniformly distributed, over connected, short headed studs) exhibited (12.49) ton load capacity. The load capacities values of the tested joists ranged between (67%-85%) of the predicted values according to the analytic model.

The consequence of mixing pure ethanol with gasoline on the pollution and performance of SI engine are investigated experimentally in the existent study. The SI engine that employed in the experiment is a single cylinder four stroke. Analysis is carried out for engine operation parameter, CO2, CO and unburned HC productions. The measurements are recorded for several engine speeds from 1500 – 3000 rpm with load and ethanol addition of (0E, 10E, 20E, 30E, 40E, 50E,). The results displayed increasing in brake power, and brake thermal efficiency while the brake specific fuel consumption decreases when the ethanol- gasoline blends fuel increases. Also it was found that CO, HC, and CO2 concentrations decrease when the ethanol- gasoline increases. The best results obtained in the study is for the blend of E-50

In this paper, the experimental thermal performance for a parabolic trough solar concentrator (PTSC) combined with helical tube receiver and directed by two axes solar tracking system at different amount of water flow rates has been analyzed. The experimental test results of thermal performance with regard to temperature rise of water, useful heat gain and collector thermal efficiency for the PTSC prototype at controlled water flow rates (2.3, 22.5 and 29.4 L/h) are collected. The results show that the increase of water mass flow rates causes decrease in the average water output temperature as (120.8, 63.82 and 46.08oC), respectively, the maximum outlet temperature becomes (160.5, 76, 47) oC, respectively, and thus, the average useful heat gain will be (1249.4, 732, 732.5W), respectively and the average thermal efficiency decreases as (73.021, 49.51 and 44.31 %), respectively. The experimental results show that decrease the water mass flow rate by 74.4%, causes an increase in the thermal efficiency of the PTSC by 64.7%.

Low Level Laser Therapy (LLLT) is one of biotechnology its useful as produced treatment for diseases that were previously difficult to treat. Some studies claim that an improvement in hearing threshold and tinnitus symptoms by Low Level Laser therapy and others set no significant effect of laser treatment. The aim of this project was to evaluation effect of low level laser (LLLT) treatment on senserinurail hearing loss. The study including 16 patients divided into two groups each group consists of 8patients (first group consist of 14 ear and second group consist of 16 ears), and each group has λ=650nm+532nm and 2.78mW/cm2. The result of this project found statistically significant differences in each group ( before and after laser application) as well as a significant change in the threshold of pure tone audiometry for patients having hearing degree (40-75)dB in each group.

One of the major usages for Al–Pb alloy are bearing alloys because of its lubricant behavior of Pb phase component. Applications of these alloys are in heavy duty, such as boring mills, presses, lathes, milling machines and hydraulic pump bushings. In present work, SiC powder was selected as additive for improving the mechanical properties of Al-Pb alloy that produced by mechanical alloying method. The percentage weight of SiC powder are (2.5, 5,10, 15 %) which mixing together with Al- Pb alloy for two hours in ball milling device, then compacted and sintering to obtain the improved alloy, and examine the mechanical properties (compressive strength and microhardness) of produced alloy . Results show that the additive of SiC powder on the Al-Pb alloy lead to improve the microhardness which increased with increased the percentage of additive, in the other hand , the compressive strength had a reverse effective with increased the percentage of SiC powder.

The composite opened web steel joist supported floor systems have been common for many years. It is economic and has light weight and can embed the electrical conduit, ductwork and piping, eliminating the need for these to pass under the member, consequently eliminate the height between floors. In order to study the joist strength capacity under the various conditions, it had been fabricated seven joists composed of the steel and concrete slab connected to the top chord by shear connectors (headed studs). These joist have 2820 mm length c/c of the supports and 235 mm overall depth. In the present study, six variable parameters are adopted (Studs distribution, Degree of shear connection, Degree of the web inclination, Shape of the web, Density of concrete for slab and length of the shear connector). The test results exhibited that minimum strength capacity was 160kN for light weight joist and maximum capacity was 225kN for joist of long shear connectors at failure. The results were compared by ultimate flexural model by Azmi.

In this paper an experimental works conducted to study the behavior of R.C. beam with large web opening at different locations and fortified with reactive powder composite (RPC) at the extreme tension zone (bottom edge of opening) and/or extreme compression zone (Top edge of opening).The experimental study is investigate the behavior of twelve beams and study the ability of using normal strength concrete together with RPC in the same section to exploit the advantages of these two materials in optimal way. The main variables are RPC layers locations in tension zone and/or in compression zone and the locations of openings. The ultimate loads, load mid-span deflection behavior and strain for steel and concrete were discussed. The experimental results showed that the ultimate strength was decreases with increasing number of opening about 4% for beams with two openings located in shear zone and 21% for beams with three openings, thus indicating that the stiffness decreases accordingly. The using RPC layers effectively enhanced performance of hybrid beams when compared with using the normal strength concrete layers only. The using RPC layers in compression and tension zones increased the ultimate load about 47 % for beams with two opening located in shear zone, when using RPC in the tension zone and normal strength concrete in the compression zone the ultimate flexural load and ultimate deflection increase little compared with normal concrete.

This research deals with the extent to which corrosion affects the behavior of buckling for 6061-T4 aluminum alloy under increasing compressive dynamic loads. Two types of columns, long, and intermediate were used.1% of the length column is the allowable lateral deflection. This is called the critical buckling of the columns. For the purpose of calculating the critical deflection, a digital dial gauge was used and set at a distance of 0.7 of column length from the fixed end condition for the column. The experimental analysis revealed that the corrosion time negatively affects the mechanical properties of materials such as the corroded specimens of 60 days (The least time to observe the corrosion of aluminum in the soil) which have approximately 2.7 % reduction in ultimate strength compared with the non-corroded specimen. Increasing the corrosion time reduces the critical load such as the maximum reduction will be 4.24% in critical buckling load for 60 days’ corrosion time. The results obtained were experimentally compared with the theoretical formulas of the Perry-Robertson and Euler-Johnson formula with the results of the ANSYS. It was found that the Perry-Robertson formula has a good agreement with the experimental results with a safety factor of 1.2, while the Euler-Johnson formula agreed with the experimental results taking a safety factor of 1.5. The ANSYS results showed a good agreement between the measured and calculated values by taking 1.1 factor of safety.

Fourier transformation Infrared spectroscopy (FTIR) has been used to characterize and measure the concentration of acid sites (Si-OH-Al groups) in NaH-13 X Zeolites. Ion exchange was followed by dealumination to get (28, 40, 65, 85.8 and 97.5 Wt. %) of NaH-13 X Zeolites samples. The conclusion of homogeneity of OH groups was obtained by analysis of Fourier transformation infrared spectroscopy absorption bands of OH groups after adsorption and desorption of Ammonia. It found that there were different acid sites on a broader absorption (3,800-3,000 cm-1) corresponds to hydroxyl groups of the less acidic Brønsted acid sites approximately at 3464cm-1 and the more acidic at 3441cm-1 and Lewis acid sites was found at 1636 cm-1 which is few and weak acid sites .It can be conclusion that concentrations of OH groups increased with increasing the exchange degree and delamination. The concentration of acid sites in samples were calculated from stretching frequencies and extinction coefficients of OH bands, also the frequency shift ΔνOH = 23 cm-1 which was due to the hydrogen bonding of OH groups with ammonia in 97.5 % NaH-13 X Zeolites. Knowing the acidity of catalyst is important for the reactions which required acidic surface.

Diabetes is one of the most critical diseases in the world which requires measuring the concentration of glucose also the injection of insulin to control the glucose rate in the body. The proposed controller is applied to the Bergman’s three-state minimal patient model, where the model is considered certain but with unknown meal. In the present work, a nonlinear controller is designed to control the concentration of glucose based on the Backstepping approached with a sliding mode for observing the disturbance meal. So will have estimated the meal and have canceled the effect that the glucose concentration has regulating to the basal level.
The effectiveness of the proposed controller, which represent the insulin dose, is proved via simulating the Bergman’s model with designed controller via MATLAB Simulink software. The result clarify the ability and the robustness of the proposed controller.