Engineering and Technology Journal

This study is an attempt to investigate the effect of cutting parameters on the cutting force and tool wear during turning of AISI 304 steel using tungsten carbide tool (WC). The first aim of present work was to employ the Response Surface Methodology (RSM) technique to obtain the influence of input machining parameters, such as cutting feed, cutting speed and cutting depth on the cutting force and wear of tool. Experiments were carried out in a 20 runs experimental matrix by a CNC machine according to the design matrices established by Design of Experiment (DOE) software 'version 8' with RSM technique. Cutting force was measured using a lathe dynamometer and tool wear with the help of an optical microscope. The relationships between parameters of machining and the responses (cutting tool wear and cutting force) were modeled and analyzed by RSM technique. ANOVA analysis was applied to study the impact of machining parameters on the outputs (responses) and to establish empirical equations for these responses in terms of input machining parameters. Significant quadratic models were developed with a probability (p-value ≤ 0.05) for both tool wear and cutting force. Results showed that the depth of cut is the most significant factor affecting the cutting force, closely followed by feed and cutting speed, whereas only the important parameter influencing the tool wear was appeared to be the cutting depth. Also, the results manifested that the optimum value for minimum tool wear and minimum cutting force was found at (80 m/min) cutting speed, (0.2 mm/rev) feed and (0.4 mm) cutting depth. A good agreement was found between the experimental and predicted results with a maximum error of 8%.

This study provides practical results in the use of the composite from sulfate resistance Portland cement (PC) and Quicklime (LQ) to improve and stabilize of soils in Al - Zaafaraniya site in Baghdad governorate and the Garma Ali site in Al Basra governorate, Iraq. PC and LQ were added in percentages of 2,4,6,8 and 10% and 2 and 4%, by dry weight, respectively. Laboratory tests to determine Atterberg,s limits, standard proctor test, USC test and UUU test (unconsolidation, undrained and unsaturated) were conducted. The results achieved a significant improvement in workability, unconfined compressive strength and shear strength. The results of the unconfinedicompressiveistrength test and UUU test for natural and improved soil reveal that the shear strength increase as lime and cement content increase and with increasing curing (0, 7 and 28)days.

This work is focused on some affecting parameters in Wire electrical discharge machining process for AISI 1012 steel by using brass wire and zinc coated brass wire with 0.25mm diameter. Pulse on time, pulse off time, spark gap voltage and servo feed had been studied as input parameters while wire wear ratio, metal removal rate and surface roughness were the outputs. The experiments showed that increasing pulse on time would increase wire wear ratio, metal removal rate and surface roughness. While, increasing pulse off time, spark gap voltage and servo feed will cause a little increase in wire wear ratio, decrease metal removal rate and improve surface roughness. Artificial Neural Network had been used to predict the process outputs for 16 samples, which gave good results and agreement with experimental results. Analysis of Variance had been used to find the contribution of the process parameters on outputs.

The aim of this investigation is to produce high performance lightweight aggregate concrete in actual hot- dry weather conditions, and then study the combined effect of hot-dry weather conditions on the fresh properties of high performance lightweight aggregate concrete such as workability, initial and final setting time, measuring concrete temperature, and hardened concrete properties (compressive strength, splitting tensile strength and flexural strength, modulus of elasticity). The experimental program including the use of fixed mix proportions and was carried out in a typical Iraqi summer days (under actual conditions) of different times during the day, where the mean maximum temperature in shadow in July and August usually is more than 44° C and relative humidity of about 24 %, the results were compared with the specimens prepared and casted in laboratory and others in shadow site. The results indicate that as temperature rises, and relative humidity falls, the initial and final setting time were reduced, beside that actual drop in slump. The results also show that rising placing temperatures more than allowable concrete temperature that recommended in ACI 305 does not, as a rule, lead to lower strengths. The strength performance of concrete can remain unaffected by higher placing temperatures, or it can even improve over that at lower temperatures. Using pre-soaked lightweight aggregates (pumice) as internal water reservoirs for producing this type of concrete under actual hot-dry weather condition played positive role in improvement of concrete properties by compensate the evaporation of water due to the rising temperature and decreasing relative humidity, and provide additional moisture in concrete for a more effective hydration of the cement.

This work aims at comparing between the a new modified catalyst WO3/Si-Zr and catalyst Si-Zr to obtain gasoline and diesel fraction , The new theory of aerosol nanocatalysts technology was used in the cracking of gas oil by vacuum accompanied by the vibration of the layer of the catalyst system . The one of aim of the present work is to reduce the emissions of atmosphere polluting gases such as (H2S and CO) .It is observed that this process is achieved at lower temperature compared to that conducted by industrial cracking process at 250 Co , and lower amount of catalyst concentration in the reactor 2.38 (gm/m3). This technique revealed that the selectivity of light products formation for the WO3 /Si-Zr catalyst is higher than that with the Si-Zr catalyst at the new technology conditions.

In this work prepared and study a polymer composite, where use polyester resin with asbestos fiber ratio (5%, 10% and 15%). First study effect of changing reinforcement percentage by asbestos fiber on coefficient thermal conductivity (k) of polymer composite. Result show decrease in the coefficient thermal conductivity (k) of composite materials with increase of weight percentage of asbestos fiber. Second, study effect of it above reinforcement ratio on the some of mechanical properties (Impact, tensile, fracture and hardness) for polymer composite. The result indicate increase value of mechanical properties with increase weight percentage of asbestos fiber. The impact strength was (2.7 kj/m2) for pure resin where reach to maximum value (7.83 kj/m2) at 15wt% of fiber .Hardness and tensile reach to maximum value at 15% weight percentage for asbestos fiber. The result illustrate improvement mechanical properties after reinforcing by asbestos fiber and these properties rises with increased in reinforcement percentage.

Controlling the position of Direct Current servo motor is the first aim of this paper, by Bacterial Foraging Algorithm (BFA), the best Proportional – Integral - Derivative (PID) controller parameters were obtained through Mat-Lab application, including the simulation and modeling of Direct Current servo motor, BFA controller and conventional PID Controller as benchmark to the performance of BFA. Proportional – Integral - Derivative controller is a closed loop system, the error made by the Direct Current motor was corrected and determine the correct position to the desired point were controlled By integrating the Proportional – Integral - Derivative controller. Kp, Ki and Kd parameters was tuned to the find best values, which make the Direct Current Motor reached quickly the accurate position without any mistake.

In this paper a lower ratio of nano powder were used from (Al2O3 and ZrO2) (0.5, 1.5and 2. 5 wt %) from cement weight, the average particle size of nano-powder were (20nm). These powders were used in fabrication of Concrete with recycle fine aggregate was replaced Natural fine aggregate(sand) in order to be used in construction application and studies the effect on the concrete. Investigation were done on the concrete including dry density, water absorption%, porosity%, compression strength, and wear rate. The results shows that The nano-Al2O3, nano-ZrO2, and recycle aggregate were adding causes difference effect in the physical and mechanical properties of concrete. Compared with control concrete specimens (Co) results for same curing time, the density, and compression strength of concrete were decreased with addition recycle fine aggregate(RFA), while wear rate, water absorption, and porosity % were increased, the lower values of density, compression strength were decreased by (2.3%, 10.8% ), respectively, while the higher values wear rat for 7 and 28 day curing time, water absorption and porosity % were increased by (19.8%, 21.4%, 8.8%, and 5.6%), respectively were obtained with addition (50%)RFA. While, the addition nano-Al2O3 and ZrO2 with RFA were increasing the density, and compression strength, but decreasing wear rate, water absorption, and porosity %, the higher values of compression strength was increased by (9.8%), while the lower values water absorption and porosity % were decreased by (24.1%, and 16.6% ), respectively were obtained with addition (1.5%) of nano-Al2O3 and 50% RFA. But the higher values of density was increased by (9.8% ) and lower values of wear rate for 7 and 28 day curing time were decreased by (71.1%, and 66.9%), respectively was obtained with addition (1.5%) of nano-ZrO2 and 50% RFA.

Reliability is a key aspect of power system design and planning. This work aims to evaluate and improve the reliability of a power distribution network in Baghdad city. The minimal cut set method has been adopted for reliability evaluation. Evaluating the reliability requires calculating and evaluating a set of reliability indices. In this research, the reliability indices are calculated for Al_Mansour 11kV distribution network in Baghdad city. According to these indices several improvements have been proposed and simulated on the network as follows:
 Adding N/C manually switches in the network for isolating fault area and restoring the service to the remaining parts.
 Adding N/O manually switches to interconnect feeders and provide alternative supply.
 Replacing the manually switches by remotely controlled or fully automated switches with fault indicators to reduce interruption times.
 Replacing the overhead lines by underground cables to reduce the fault rates. The software CYMDIST version 7.1 has been used as a tool for the simulation of the distribution network and performing the required analysis.

The load carrying capacity of piles resulting from base resistance and shaft resistance, the load transfer mechanism of piles is complicated since the mode of failure of these components is different in addition to the effect of pile installation on the soil surrounding of piles .The intended task of this paper is studying the behavior of pile group model driven in clayey soil subjected to vertical axial loading, and the assessment of the development of resistance of each of the two components, tip resistance and skin friction of the piles of during loading. Twelve piles group tests are conducted at three grades of undrained shear strength (cu) of clayey soil which are (20 or 40 or 60 kPa) where the configuration of the pile groups used in all tests is (2 x 2). Two different pile lengths (L) are selected (300 and 450 mm), these lengths represent the slenderness ratio (L/D) of (10) and (15) respectively, so that the center to center spacing between the piles (Sp) used are (3D) and (5D). It was observed that the most of the load capacity of piles is mobilized at settlement of around (1 – 2 mm), corresponding to (5 %) of pile diameter (D) , however, the development of full shaft resistance of piles appears at a low displacement range and is only of about (1 to 2 %) of the pile diameter while the pile end bearing will mobilize at a higher displacement range in the range of (5 to 10%).The changing of undrained shear strength of clay from (20 to 60 kPa) has no significant effect on the load transfer mechanism and the mobilization of shaft resistance and end bearing with increasing the settlement. It was concluded that a low ratio load sharing of piles tip, especially with increasing slenderness ratio (L/D) , which supports the fact that the piles in the weak clayey soils behave as a floating pile which leads to neglecting end bearing capacity in calculating the total pile load capacity as indicated by some references.

In this paper the buckling behavior of composite specimen manufactured from polyester reinforced with fiberglass, jute fiber and eggshell powder were studied. Several samples with rectangular cross section area of (1.5*19) mm are prepared with length of (400, 500, and600) mm and with addition weight ratio of (5%) of different material for reinforcement, used for tensile and buckling test. Different types of natural and synthetic materials (matrix and random glass fibers
(are used first without any addition then with adding (5% SiC or 5% Eggshell powder or 5% ) to the matrix, and Jute fibers. The critical load for its best results was to the random016 fiberglass without addition but its worst results were with jute addition. The results of other additions (SiC, Egg shell powder, and matrix without addition was in between. The experimental with theoretical results has been calculate and then compared

Present work deals with the examination of the mechanical properties of Al 6061 composites, which were successfully fabricated by stir casting technique and then reinforced by using different percentages of Al2O3 nanoparticles up to 10 wt%. The required samples were carefully prepared. Evaluation of the mechanical properties such as hardness, yield tensile stress and ultimate tensile stress were effectively obtained at various percentages of Al2O3 nanoparticles .It was found that the mechanical properties of 6061 /Al2O3 nanoparticles are critically influenced by the concentrations of the reinforced Al2O3 nanoparticle, since there was a substantial enhancement in the mechanical properties, as the fractions of Al2O3 nanoparticles increased. This improvement in the mechanical properties was attributed to the uniform distribution of reinforcement nanoparticles as well as the grain refinement of aluminum matrix with minimal porosity.

The power losses in distribution system are high, which form 70 – 80% of total transmission and distribution losses. High losses have severe impact on stability, reliability as well as economy. Therefore, minimization of these losses is very necessary. In this paper proposed various schemes to reduce the active power losses in distribution network, given as:
- Optimum reconfiguration network,
- Optimum Distributed Generation (DG) placement and
- Optimum reconfiguration with optimum (DG) placement.
Using Cymdist software to implement the optimal reconfiguration algorithm and proposed Genetic Algorithm (GA) to find the size and location, which programmed under MATLAB software package. Whereon the proposed methodology (GA) simplifies the problem by dividing it in two phases, namely Placement Planning Model (PPM) and Size Planning Model (SPM) thereby reducing the search space. It was the integration of the two methods were used after each method individually to obtain minimum real power losses with better bus voltage (better efficiency for network).To verify the proposed algorithms, IEEE 33-bus system and al – jihad neighborhood distribution system (Baghdad distribution sector) are tested. The simulation results are compared with proposed works in literature.

In the present study, the effects of laser surface melting (LSM) on chromium carbide of heat treated (AISI 304) austenitic stainless steels (ASS) was studied with the aim to suppress sensitization of 304SS. Austenitic stainless steels were heated (aging) up to (800) ºC at constant holding time for two hours. LSM was conducted by using a (600 W) Yb-YAG laser. The microstructure was characterized by using optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results shows, refined and homogeneous microstructure which contains austenite (γ) as basically phase and delta ferrite (δ) as the secondary phase, however, chromium carbide (Cr23C6) phase are fully dissolved. Desensitization of heat treated ASS has been successfully achieved by LSM which reduced Cr depletion at the grain boundaries..

In this paper, the robustness properties of H-infinity control to produce a dynamic output feedback controller is applied to a human swing leg system. The double pendulum structure is usually used to model this system. The pendulum links will represent the thigh and shank of a human leg. The upper body will be connected to the thigh and then the shank via hip and knee joints. The muscles of thigh and shank are moved by applied two external (servomotor) torques at the hip and knee joints. The mathematical model of the system is developed. The results show that the proposed controller can robustly stabilize the system and achieve a desirable time response specification. The results were obtained by using Matlab program and the achieved time response specifications are raise time tr=0.18 seconds, settling time ts=0.25 seconds and maximum over shoot Mp=0.03 for hip joint and tr=0.13 seconds, ts=0.21 seconds and Mp=0.01 for knee joint.