Engineering and Technology Journal

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,sjnce feldspar is not available in Iraq, so it 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 microhardnss and dielectric properties such dielectric constant, loss tangent and dielectric loss factor were measured. The improvement of these properties could associate with an increasing of MgO additive 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

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 a 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

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.

Degassing technique is currently applied to cast aluminum alloys due to their technological and economic advantages. The present work aimed to study the effect of degassing technique of cast aluminum alloy (LM2) under different pressure 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 pressure 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 resultsshowed 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.

Nucleate pool boiling regime can be considered one of most effective ways to make viable a 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 TiO2were 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.

Silver nitrate combined with commercial sigma Nisin were used to synthesize Nisin-
Silver nanoparticles; different concentration 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.

In this paper, experimental study has been done to showing 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 providing 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) is 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

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).

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 is 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%).

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-holeswere 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.

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.

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 in obtaining low insertion loss, low return loss, insensitive to polarization, high thermal stability, large optical bandwidth and low crosstalk

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 loss about (3/5) of its initial compressional stiffness after buckling also it can be concluded that after buckling the maximum stress increases at almost four times the pre-buckling

Traffic Studies Aims (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 make traffic in this difficult intersections and which rise to 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 number of lane to 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.

Highly competitive markets are justifies the use of advanced technologies and methods to improve product’s quality and sales, which is 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.

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 were 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 presented graphically. The experimental results were analyzed by using Minitab 16 software

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.

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 ofsuch projects before work starts, using backward elimination regression analysis technique is carried out.The study covers two story (12 classes) school projectsawardedby 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 inputparameters. These factorsare;awarded bid price, average bid price, estimated cost, contractor rank, resident engineerexperience,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 avery good accuracy havinga correlation coefficient(R)of(93%),determination coefficient (R2)of(86.5%)and average accuracy percentage of(92.02%).

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).

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 little 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 by 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.