Print ISSN: 1681-6900

Online ISSN: 2412-0758

Volume 33, Issue 2

Volume 33, Issue 2, February 2015, Page 285-525

The Influence of Magnesia Addition and Sintering Temperature on The Properties of Synthesized Electrical Porcelain

Fadhil A. Chyad; Fadhaa G. Salem; Innam W. Waten; Zahraa F.Attiya

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 285-293

The influence ofmagnesia (MgO) content at different sintering temperatures on the physical and dielectric properties of synthesized electrical porcelain was investigatied.Feldspar is one of the major components of porcelain,since feldspar is not available in Iraq, so it was synthesized from Iraqi raw materials.MgO was progressively added in the range (2-30 wt. %) into electrical porcelain. The composed bodies were sintered at temperature in the range(1200-1350 C),Physical properties such bulk density, open porosity beside the Vickers microhardness and dielectric properties such as dielectric constant, loss tangent and dielectric loss factor were measured. The improvement of these properties could associate with an increasing of MgOadditive and sintering temperatures. Bulk density, microhardness and dielectric constant are increased with the increasing of MgO content and sintering temperatures. The results reveal that the highest value of density at 30wt. %MgO and at 1350 C for density, hardness and dielectric constant, while it has the lowest value for porosity and loss tangent.

Design of RF Power Amplifiers Using Parallel-Series Power Combining Transformers

Suhad. H. Jasim; Ahmed S. Ezzulddin

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 294-307

This paper presents the design of a one watt-level RF CMOS Power Amplifier (PA) based on power combining transformers PSCT in 0.13 µm technology using ADS 2011.10. The PA incorporates a parallel combination of four differential PA cores to generate high output power with acceptable efficiency and linearity. The first part the design for class-AB PA for WLAN applications is presented. The PA delivers an Output Power (Pout) of 30 dBm, Power Gain (Gp) of 30 dB and 40% PAE using 2.5 V supply. In the second part class-E PA is designed to provide an output power of 30 dBm, power gain of 30 dB, and 54% PAE at 2.45 GHz using 1.6 V supply. The layout of the transformers is designed and simulated with momentum RF EM simulator of ADS 2011.10 in order to realize a fully integrated power amplifier. The simulated efficiency of the designed transformer was 78% with minimum insertion losses (ILmin) of 0.87 dB.

An Automated Optimization Technique of a MSPA for Broadband Communication

Ali Owda Abid Noor

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 308-319

In this research paper, an automated design technique is used to optimize the variables of a microstrip patch antenna (MSPA), for reliable broadband communication systems. The method is based on a computerized procedure to produce a special defect in the ground plane, alongside with dimensions optimizing using genetic algorithm. Conventionally, either cut and try, or dimension optimization is used separately for this purpose. The novelty of the method presented here resides in the fact that the cut and the optimization techniques are automated to produce an wideband antenna. The resulting antenna gave a return loss of less than -10dB between 3GHz and 8GHz i.e. a bandwidth of 5GHz. Compared to other literature techniques, the achieved bandwidth is considered to be the best. The dimensions and the bandwidth of the designed antenna are attractive for next generation communication systems.

Effect of Degassing Process of Squeeze Casting Aluminum Alloy on Tensile Strength Under Different Pressures

Hussain J. Al-alkawi; Dhafir S. Al-Fattal; Samih K. Al-najjar

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 320-330

Degassing technique currently applied to cast aluminum alloys due to its technological and economic advantages. The present work aimed to study the effect of degassing technique of cast aluminum alloy (LM2) under different pressures using squeeze casting process. Inert argon gas was pumped into the molten aluminum with flow rate (2,5-5-7)l/min. at constant pumped duration (5min.). Different applied pressures were used(17, 35, 52) MPa. The test was performed at room temperature. The physical and mechanical properties of degassed samples were measured and compared with non-degassing (ND) samples. The results showed that the best condition of degassing is found at 2.5 l/min flow rate and 35 MPa applied pressure. It was found that a slight difference is observed for the density and the lowest value of porosity was obtained at 2.5 l/min flow rate and 52 MPa applied pressure.

Synthesis and Optimization of Nisin-Silver Nanoparticles at Different Conditions

Qusay J.Rasheed

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 331-341

Silver nitrate and commercial sigma Nisin were used to synthesize Nisin-Silver nanoparticles; different concentrations of Nisin at different pH conditions were used to optimize the characterization.10 μg/ml at pH 6.0 had the greatest observation and the deferent conditions characterization of Nisin-Silver nanoparticles agreed with that different methods were used to prepare the Nisin-Silver nanoparticles and the results showed that the best method to prepare the nanoparticles (Nisin-Silver) was sunlight method.

Experimental Study of the Thermal Contact Resistance in Fin and Tube

Ahmed A. M. Saleh; Abd al-satar Hamid Hussein

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 342-349

In this paper, experimental study has been done to show the effect of the Thermal Contact Resistance (1/hc) in fin and tube. Three types of fin-tube design Embedded, Welded and L-footed are used in the test. Vacuum chamber with dimensions (45 cm length, 35 cm height, and 15 cm width) has been used for testing the sample of fin-tube, that’s placed inside the vacuum chamber. Vacuum pump is used to provide surrounding approximate emptied from air. The sample of fin-tube consists of hot water tube and cold water tube, the fin is fitted between themes. The experimental results showed that the thermal contact resistance decreases as the heat supply (source) increase. And the thermal contact resistance decreases when temperature drop at interface contact surfaces decreases. The results obtained of (1/hc) are least for embedded type and greatest for L-footed type. The thermal contact resistance (1/hc) of L-footed finned tube is higher than the others, by (250%) than the Embedded fin- tube type, and by (160%) of welded fin-tube type.

Tool Path Generation for CNC Milling Based on STL File

Nadia Sami Hasan; Laith Abdullah Mohammed

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 350-361

This paper proposes and develops algorithms to read (STL) files and extract engineering entities required in CNC milling processes. The proposed algorithms are dependent on some mathematical modeling and manipulations of the engineering models by slicing an (STL) file to many slices and then building the required algorithms to adopt these slices to generate machining paths for CNC milling machines as (G-Codes).
The proposed system is divided into three parts, in the first part, an algorithm proposed to extract engineering object entities to some proposed models based on their (STL) files using Matlab program. The proposed models include cube, cylinder, dome, cone and cavity models. In the second part, a slicing algorithm is proposed to enable the slices along the proposed models z-axis to find and navigate the required manufacturing data. UGS program was used also to generate the tool paths and to simulate the machining process and then generate NC part program of the proposed objects (G-Code). Finally, the third part of this work includes comparing results produced based on both (STL) and (UGS), to achieve the required aim of this paper by experimentally comparing objects surface roughness, resulted values show that the maximum difference in average Ra is equal to (0.27µm).

One- Dimensional Cutting Stock Problem in Al- Mansour Company

Sawsan Sabeeh; Salam Qaddoori Dawood

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 362-371

When short items are being cut out from long objects, the One- Dimensional Cutting Stock Problem (1D-CSP) is being appeared and caused increment in wastage material amounts, so the primary purpose of this paper is to use integer linear programming (ILP) based on Advance Interactive Mathematical Modeling System (AIMMS) software to minimize the trim losses which are resulting from one dimensional- long objects and also to reduce the total number of used stocks. Reinforcement Steel (Rebar) is used in building structure at Al-Aziziyah Housing Project by Al- Mansour Company as long objects with standard lengths and different diameters which are representing four problems according to these diameters (25 mm, 16 mm, 12 mm, and 10 mm). The implementation of that software is very effective to present optimal solutions, where the utilization stock ratio reached to (99.51%).

Experimental Investigations of Hole - EDM to Optimize ElectrodeWear through Full Factorial of Design of Experiment

Shukry H. Aghdeab; Laith A. Mohammed

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 372-379

Electrical discharge machining (EDM) is a process where the material removal of the workpiece is achieved through high frequency sparks between the tool (electrode) and the workpiece immersed into the dielectric solution. It is commonly used to produce moulds and dies, to drill small, burr free holes and to make prototypes for the aerospace and electronics markets. In this work, micro-holes were fabricated on copper alloys by using EDM. The output responses investigated was electrode wear weight (EWW). Full factorial of Design of Experiment (DOE) module in Minitab was used as a principal methodology to examine the effects of current and machining time over output responses. Experimental results indicate that the EWW was mainly affected by current, and can be reduced by increasing the current parameter. Minimum EWW (0.12gm) obtained at 10A.

Application of Adaptive Neuro-Fuzzy Inference System for Prediction of Surface Roughness in Incremental Sheet Metal Forming Process

Aws K. Ibrahim; Wisam K. Hamdan

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 380-399

In manufacturing processes, surface finish of a product is very crucial in determining the quality. Therefore, the surface quality including the surface roughness is still the most important obstacles against the incremental sheet metal forming (ISMF) process. As a consequence, the possibility to predict the surface roughness values in incremental forming and to correlate these values with the forming parameters can be useful in order to control this important target. Accordingly, an adaptive neuro-fuzzy inference system (ANFIS) is used to predict the surface roughness of parts produced by single-point incremental forming (SPIF) process. The hybrid learning algorithm is applied in ANFIS to determine the most suitable membership functions (MFs) and to simultaneously find the optimal premise and consequent parameters by directly minimizing the root mean squared error (RMSE) as a performance criterion. In order to achieve this target, five forming parameters, namely (tool diameter, incremental step size, tool shape, rotational speed and slope angle) are studied to form pyramid like shapes for the purpose of roughness measurement. Experimental results show that the difference sigmoidal MF gives the minimum RMSE. The predicted surface roughness values using ANFIS are compared with actual data. The comparison indicates that the utilization of difference sigmoidal MF in ANFIS could achieve a satisfactory prediction accuracy using both training and testing data when this MF is adopted. The training and testing prediction accuracy are 95.972% and 85.799% respectively.

Simulation & Evaluation of (OADM) Based on Bragg Gratings and 3dB MMI Couplers

Aied K. Mohammed; Raheel J. Hassoon

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 400-414

In this paper, an approach has been proposed to design an (OADM) made in silica- on silicon waveguide by combining Bragg gratings (BGs) and 2x2 3dB multimode interference couplers (3dB MMI coupler) in a Mach-Zehnder interferometer. This design technique shows an interesting result to obtain low insertion loss, low return loss, insensitive to polarization, high thermal stability, large optical bandwidth and low crosstalk.

Effect of Post-Buckling on The Stiffness and Stress of Plate

Hani Aziz Ameen; Kayser Aziz Ameen; Ibtissam Mahdi shihab

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 415-430

This paper presents a theoretical investigation of post and pre-buckling of the simply supported plate. The effect of post and pre buckling on the stiffness of plate is determined. The full derivation of the equation described the ratio of stiffness of plate in the post to pre buckling is derived and from this equation it can be deduced that the simply support plates lose about (3/5) of their initial compressional stiffness after buckling also it can be concluded that after buckling the maximum stress increases at almost four times the pre-buckling.

Analysis of Traffic Operation for AL-Kafa’at Signalized Intersection in Al-Kut City

Abbas Z. Khalaf; Hasan Hamodi; Mohammed Riyadh

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 431-439

Traffic Studies Aim (Traffic analysis) to estimate some of the important indicators to determine the level of service (LOS) at intersections in the cities. That's where the increase in traffic volumes at intersections is one of the main problems that makes the traffic difficult in these intersections and which raises congestion in these areas.
The objective of this research is to evaluate the operational capacity of intersection (AL-Kafa’at) in AL-Kut city and show better proposals to improve the performance in terms of capacity.
To achieve these objectives traffic information has been collected using digital camera to various directions for the purposes of analysis and traffic engineering while HCS traffic program is used for the purposes of traffic analysis process. The operational analysis of the existing conditions of this intersection indicates that the LOS is (F) with an intersection delay value of 105.1 sec. /vehicle .Because of the reasons above, it is important to enhance the performance of AL-Kafa’at Intersection by increasing the number of lanes to the right turn for Alhaidariya Approach. The results indicate that the intersection LOS is hanged to (D) with a cycle time of 91 sec. and an intersection delay of 38.1 sec. /vehicle.

Improvement of Motor Performance By Applying 6-Sigma (Dmadv)

May George Kassir; Shatha Mouayad Mahdi

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 440-450

Highly competitive markets justify the use of advanced technologies and methods to improve product’s quality and sales, which are the survival of any organization involved in business to be adaptive, proactive, and responsive to changes and has the capability to provide customer expectations. The success of products depends on how well they meet customer requirements. In order to achieve competition in Iraqi market, and to get high quality performance, Six Sigma has been applied in the “State Company for Electrical Industries” on motor of (1/4) HP. It is important to evaluate product strengths and weaknesses among competitive products available in Iraqi market to get the needed specifications to implement it in QFD )HOQ). The calculations were carried out by using “sigma xl version 6.2” program. Six sigma methodology: DMADV was adopted. Quality Function Deployment (QFD) was applied to improve motor performance. Thirty questionnaires were distributed and collected back to build QFD Matrix which determines four problematic issues with high scores: starting current, losses, coil winding, and rotor dimensions which indicates the need to resolve. Referring to QFD results which indicate the starting current is one of the main problems of motor performance, the researchers suggest motor redesign by adding “Soft Starting Circuit” to resolve this problem. Starting current for motor was measured and found to be 5.2 amp, while it decreased to 3.2 amp after redesign. Motor performance will be improved, cause the reduction of losses from 312 to 128 watt.

Prediction of Bead Width In Submerged ArcWelding of Low Carbon Steel (AISI 1005)

Husham Jawad Kadhim; Ahmed Ali Akbar Akbar

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 451-462

This paper used Taguchi technique to determine the optimal SAW parameters, an effort has been made to study the effect of SAW process parameters (current I, voltage V, speed S) on the weld bead width (W) of low carbon steel AISI 1005. S/N ratios are computed to determine the optimum parameters. Statistical model was checked by used multiply regression method; the adequacy and significance of the model were checked by using ANOVA technique. The model employed easily in form of executed program designed by using visual basic 6 software, the objective of designed program is to predict and control weld bead width, which enable to put in the desired weld parameters and select the weld bead width. Main and Interaction effects of the process parameters on bead width were presented graphically. The experimental results were analyzed by using Minitab 16 software.

Groundwater Quality Assessment in Urban Area of Baghdad, Iraq, Using Multivariate Statistical Techniques

Alhassan H. Ismail; Muntasir A.H; Reem J. Channo

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 463-476

An attempt has been made to assess the overall groundwater quality and identify major variables affecting the groundwater quality in the urban area of Baghdad, Iraq. Groundwater samples from tube wells of 66 sampling sites were analyzed for the major physicochemical variables during May 2010. From the Hill–Piper trilinear diagram, it is observed that the majority of ground water from sampling sites are Ca2+ -Mg2+ -Cl- -SO42- type and Na2+ -K+ -Cl- -SO42- type water. Multivariate statistical techniques such as factor analysis and cluster analysis were applied to identify the major factors (variables) corresponding to the different source of variation in groundwater quality of Baghdad. Factor analysis identified three major factors explaining 82.506% of the total variance in water quality; and the major variations are related to degree of mineralization of the geological components of soils, irrigation return flow, agricultural activities and mixing of wastewater. Hierarchical cluster analysis revealed three different groups of similarities between the sampling sites, reflecting different physicochemical properties and pollution levels in the groundwater quality.

Forecasting the Final Cost of Iraqi Public School Projects Using Regression Analysis

Zeyad S. M. Khaled; Qais Jawad Frayyeh; Gafel Kareem Aswed

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 477-486

The actual final cost of public school building projects, like other construction projects, is unknown to the owner till the final account statement is prepared. An attempt to predict the final cost of such projects before work starts, using backward elimination regression analysis technique is carried out. The study covers two story (12 classes) school projects awarded by the lowest bid system. Records of (65) school projects completed during (2007-2012) are employed to develop and verify the regression model. Based on experts ‘convictions, nine factors are considered to have the most significant impact on the final cost. Hence they are used as model input parameters. These factors are; awarded bid price, average bid price, estimated cost, contractor rank, resident engineer experience, project location, number of bidders, year of contracting, and contractual project duration. It was found that the developed regression model have the ability to predict the final cost (FC) for school projects, as an output, with a very good accuracy having a correlation coefficient (R) of (93%), determination coefficient (R2)of(86.5%)and average accuracy percentage of(92.02%).

Different Shapes of Carbon Nanotubes via Water Assisted Chemical Vapor Deposition

Kahtan Kalaf Al-Khazraji; Ali Hussain Ataiwi; Mayyadah S. Abed Al-Fatlawi

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 487-499

Carbon nanotubes with different shapes have been prepared using water assisted chemical vapor deposition technique (WA-CVD). Different thicknesses of nickel layers were sputtered on alumina substrate. These were treated under high temperature (700 °C) at hydrogen gas to grow nickel nanoparticles (Ni-NPs). Tube furnace (single type), argon and acetylene gases were used for Carbon Nanotubes (CNTs) growth. The FESEM, TEM, HRTEM, Raman spectroscopy, and XRD were used for characterization of the carbon product. The results show that Water Assisted CVD produces CNTs with no trace of amorphous carbon. Nickel catalyst thicknesses (0.5,1,3,3.45,6.8,100 nm) offer different shapes of carbon nanotubes (single walled carbon nanotube, plain MWCNT, helical carbon nanotube, carbon nanofiber).

Effect of Practical Curing Methods on the Properties of Roller Compacted Concrete

Hisham K. Ahmed; Intesar Kadhim Gata

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 500-511

Roller Compacted Concrete (RCC) is a technology characterized mainly by the use of rollers for compaction. This construction method permits considerable reduction in costs and construction time of dams and roads. It is necessary to study the curing of RCC especially in hot weather because RCC has no slump and has low W/C ratio. Therefore the primary scope of this research is to study the effect of various curing methods (continuous watering, wet burlap, nylon, sprinkling, curing cycles, and curing compound) after 24 hrs from casting on the physical properties of roller compacted concrete.
The mix proportion which was used in this investigation, was designed and laboratory tried on the basis of using 250 kg/m³ of Ordinary Portland Cement. This work involves preparing cylindrical specimens with (diameter of 150 mm and height of 300 mm) for measuring the compressive strength, splitting-tensile strength, and static modulus of elasticity. And it also includes prism specimens with (100×100×400 mm) for measuring the modulus of rupture (flexural strength).
Results show that the curing of RCC with continuous watering clearly improved the RCC properties. The results also indicate that the RCC specimens without curing (left in air) suffered from permanent loss of strengths ranging between 20 to 25 % when compared with continuous watering at age of 28 days.

Pool Boiling Heat Transfer Using Nanofluids

Jamal M.Ali; Balasim Ahmed Abid; Kheria M. Essa

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 512-525

Nucleate pool boiling regime can be considered as one of the most effective ways to make a viable great amount of heat exchange in a relatively small area. To investigate the characteristics of HTC (Heat Transfer Coefficient) enhancement using nanofluids, pool boiling HTC experiments of two water – based nanofluids with alumina Al2O3and titanium TiO2 were performed using electrically heated flat plate and heating element made of stainless steel under atmospheric pressure.Systematic experiments were carried out with pure water and nanofluids containing, Al2O3 and TiO2 nanoparticles in different concentrations of (0.05w %, 0.1w %, 0.3 w%, and 0.5 w %). A comparison is made between nucleate boiling of pure water and a widely used correlation proposed in 1952 by Rohsenow is done. The results show good correspondence. Pool boiling heat transfer coefficient and phenomena of nanofluids are compared with those of pure water. The experimental results show increase in the heat transfer coefficient value and decrease in the surface superheat temperatures of heating element. This value increases with increasing nanoparticles concentration. The best nucleate boiling heat transfer performance enhancement is generally observed to be at Al2O3 nanofluid, compared to that of TiO2nanofluid and pure water.