Iraqi journal of mechanical and material engineering

This paper is aimed to study the effect of solution heat treatment on mechanical properties of Al alloy AA 2024-T6 (Tensile, hardness, wear resistance), many specimens were prepared according to ASTM and then heated to 500ºC for one hour and water quenched.Artificial aging carried out at 190ºC for (1, 2, 5) hours and cooled slowly by air to show the effect of aging time on mechanical properties, many examinations (Microstructure, hardness Tensile and wear test) were done for specimens.From the obtained results it can be see that heat treatment contributed in mechanical properties improvement.

This research studies the effects of adding industrial wastes admixtures with different percentages on the thermal and mechanical properties of concrete hollow blocks (CHB).Different types of admixtures were used in this work ,including ,rubber cuttings ,wood saw dust and barley reeds ash with(5% ,10% ,15% ,20% ) percent of each one . Thermal conductivity ,specific heat capacity, compressive strength ,flexural tensile strength and variation of density have been examined for each specimen at all percents of admixtures , and comparing with the reference concrete specimens.. From the obtained test result ,the study concluded that the use of these admixtures in (CHB) significantly effects of thermal conductivity , specific heat capacity ,compressive strength ,flexural tensile strength ,especially at (5%) of adding materials ,as well as utilization of additives in (CHB) to produce low density mixtures with barley reeds or as high density concrete using when rubber cuttings in the (CHB) mixture.

An reciprocating air compressor type ( V-AK 150 ) of three compression rings is employed in this work to accomplish the experimental work . The indicator diagram is recorded at different compressor speeds. The present work elucidates the measurement and indication of gas pressure within compression space as a function of crank angle. The study contains the prediction of pressure in inter-ring volume pressure behind piston ring during compressor operation. For verification of a mathematical model a static test rig apparatus is designed in order to measure the inter-ring volume pressure within the range of compression pressure (1-50 bar).The comparison between mathematical and experimental results show good agreement.

The energy saving is very important in the practical application engineering . This research studies on this subject in the field of air conditioning. A numerical program has been developed to obtain the thermal response of different walls to energy sources ( solar and ambient temperature ) in summer of Iraq. Anew local natural insulation is used to reduce heat gain to air-conditioned space. This work proposed to used local natural insulation from palm fiber , local cane mat and local plastic mat to save energy required to condition a space . A finite element solution for heat flow through wall is used with suitable iteration solution where boundary conditions are varying due to solar radiation and environment thermal load. The result- in saving of about 50% of energy that may pass through walls when used mat cane local compared to the mat plastic local and palm fiber.

The study was done to predict rates of wear which occurred as a result of friction process between a brass material and a carbon steel disc was rotated with speed equal to 675 r.p.m. The wear rates were calculated for a dwell time equal to 30 minutes for each case of applied loads of 250g, 750g and 1250g. This research investigated the effects of loads applications on the variation in temperatures which were taken place due to rubbing action at contact area that may play role in specifying the wear rates. These results have indicated the style of wear rates expressed by volume and by weight that may be a guide for the designers when using those materials at similar friction conditions

Natural materials that are available in large quantities or certain waste from agricultural operations may have the potential to be used as low cost adsorbents, as they represent solid waste, widely available and are environmentally friendly after use it. The aim of this research is to evaluate the applicability of using one of these locally available materials (sawdust) to improve the sewage effluent quality.The sawdust, low cost locally available material and solid waste, was tested as biosorbent for the removal of biochemical oxygen demand (BOD5) from effluent sewage. Adsorption of BOD5 onto this low-cost adsorbent was studied by continuous mode system. The effects of initial BOD5 concentration, flow rate, bed height, particle size, activated carbon/sawdust ratios and pH on adsorption capacity were studied. The experiments showed that the adsorption through the sawdust instead of commercial activated carbon was found to be very effective for the removal of BOD5, where the maximum removal percentage reached 86.23%.

This paper proposes a control of robust active damping for a quarter car model with three degrees of freedom by using an optimal control approach. The design takes into consideration the uncertainty of system parameters. The solution to the robust damping problem is obtained by translating it into an optimal control problem, and the subsequent design of appropriate feedback controllers for the active suspension system can be obtained by solving the LQR (linear quadratic regulator) problem. The results show that the proposed robust design provides superior kinematic and dynamic performance compared to those of the passive system.

The effect of thermal shock on bending test of composite laminated simply supported rectangular beam is investigated experimentally and numerically.In experimental part, three types of fiber reinforcement [Matt fiber glass (600 kg/mP3P) and Random fiber glass(450 kg/mP3P, and 300 kg/mP3P)] are used with polyester resin. The flexural bending test with and without thermal shock load on top or bottom surfaces of the specimen are investigated. The heating and cooling temperature applied are (70CPoP and -30CPoP) respectively. In numerical part, the ANSYS software is used to compare the results with the experimental work. Effect of volume fraction is also investigated. The results showed that, the increasing volume fraction causes decreasing the maximum deflection. Random fiber glass (300 kg/mP3P)composite materials gives minimum deflectionwhen compared with other two types of fiber for same volume fraction. The heating on top surface and cooling on bottom surface of the beam causes decreasing in maximum deflection.The cooling on top surface and heating on bottom surface of the beam causes increasing in maximum deflection. Good comparisons are found between experimental data and numerical work.

This research involved a study of aerodynamic analysis to determine the load on a wing of a manned aircraft using ANSYS11 software program. Awing of aircraft at Mach number (M=0.4) has been modeled in this program to determine the pressure distribution on both wing sides for steady and unsteady states. The wing has been tested at three angles of attack, namely ( , , ). The pressure distribution on the wing has been used to evaluate the stress distribution and displacement for the wing structure. The stress analysis has been carried out for the skin shell of the wing and the internal stiffeners of the wing box. The result obtained in the present work showed that the maximum Von Misses stress occurs at distance of 0-15% from the edge of wing, especially at the corners at which spars web extending from the wing and root ribs intersects the wing skin.

This work presents nonlinear proportional feedback controller design for the active braking system. The controller objective is to maximize the deceleration braking force by forcing the slip ratio to attain the maximum value, where a magic formula is utilized to model the friction force to slip ratio for various road conditions. The validity of the proposed controller is proved, first, based on Liapunov function approach taking into consideration the uncertainty in system model. Then, the simulation results using MATLAB/Simulink showed the effectiveness of the proposed nonlinear controller in reducing the vehicle velocity to the desired velocity (5 km/hr) in a minimal period of time in presence of model uncertainty and for various road conditions.

This paper presents an analytical model of the pressure force and vibratory response of the cylinder induced by the piston movement of compression ignition engine. In this method, the equation of motion for the coupled system of piston and cylinder is derived, taking account of three – degree of freedom system of the piston to simulate accurately time of the pressure force and vibratory response. The characteristics under different engine torque conditions of acoustic emission and vibration signals of the compression ignition engine from a baseline test are presented in this work. The purpose of this research is to investigate relation the engine vibration and noise with engine performance parameters ( indicated specific fuel consumption, indicated power, indicated pressure and indicated thermal efficiency), and the effect of different pressure forces on vibrations in a small diesel engine. The investigated parameters are indicated engine performance parameters, sound pressure level (SPL) and vibration generated from engine are calculated using cylinder pressure measurements. A MATLAB program is developed to get the pressure forces and vibration amplitudes in the three – dimensions. It was found that the peak amplitude of acoustic emission root mean square (RMS) signals correlating to the impact like combustion related events decreased in general as the engine torque increases. It is also noticed that the peak amplitude of the acoustic emission RMS attributing to indicated specific fuel consumption increases as the engine torque decreases. The calculation performance of the combined system is 76.72% when tested on the validation (theoretical) set and 75.47% on the final test set. The calculated results by MATLAB program show that the pressure forces and the piston vibration amplitudes agree well with measured results with relative true error of 3%.

Heat transfer mechanism model was predicted in order to simulate the temperature distribution of the two phases (glass-air) through the macrostructure of porous media sample in depth 20 mm at local equilibrium. It has been heating the sample from left side through x-axis with different values of heat flux. The model contain two stages: firstly, predict the temperature distribution in solid phase by transient 2-dimensional conduction heat equation; secondly, switching was happened in the program to simulate the temperature distribution in fluid phase of sample by energy balance. It has been found the temperature distribution in glass and air through the first two layers of series configuration of the sample. It showed very small values of heat transfer coefficient between these layers. That means high insulation property was observed from this structure of porous media sample. Due to the heating process, it has been noted the air inside the first layer was accelerated a very little bit as marks the onset of convection. This is due to the pressure gradient was produced between the outside and inside layers of sample through heating process with time. Darcy law was used to calculate this air velocity. Heat transfer coefficient inside porous media, effective Nusslet number and Nusslet number of fluid phase were calculated.

Zinc borate was added as a surface layer of (4mm) thickness on the surface of araldite resin reinforced by woven roving carbon-kevlar fibers .This system was exposed under different exposure intervals (10,15, and 20mm) to a direct flame which generated from oxyacetylene and gas flame (3000ºC,2000ºC) respectively, and study the range of resistance of flame retardant material layer to the flames and protected the substrate . Surface temperature opposite to the flame method was used to measuring the temperature transferred through this system. The experimental results show that a great increment in thermal resistance and flame retardancy after coating by zinc borate and the best percentage was (20%) from zinc borate, as well as rising flame resistance increased exposure intervals to flame

This research investigates experimentally the thermal conductivity and the pressure drop of a new kind of engineering materials consisting of nanometer sized particles dispersed in base fluid named nanofluid. The study investigatesnanofluids containing CuO and γ-AlR2ROR3R oxide nanoparticles in distilled water as base fluid in different particle sizes and concentrations. The experimental results emphasize the enhancement of the thermal conductivity due to the nanoparticles presence in the fluid.Also the effect of the particle size and concentration on the thermal conductivity. These results show noticeable enhancement in the thermal conductivity especially for the CuO/distilled water nanofluid which reaches to (1.07%), while reaches to (1.05%) for theγ- AlR2ROR3R/distilled water nanofluidat the concentration of (6 % vol.) and at the room temperature.The experimental results of pressure drop show that the nanofluids in the laminar flow will not cause extra penalty in the pumping power. A good agreement was found between the experimental obtained data for this research and other results from published papers.

The vibration analysis and stability of curved pipe with linear spring stiffener for fixed-fixed ends conveying fluid consisting from several of straight pipe elements is investigated by using three dimensional finite element model. The characteristic matrices consisting of stiffness, inertia, damping and contradictory terms which derived by finite element method and the effect of the internal flow velocity, axial force, Coriolis force and force of spring stiffener in connected elbow are considered. Some parameters that affect the dynamic characteristic have been studied such as curved pipe angle, location of spring stiffener, diameter ratio and wall pipe thickness. It is found that the location of spring stiffener would influence the critical flow velocity and the natural frequency of the system. Where the natural frequency of curved pipe increased with closed the spring stiffener to center of curved pipe as the flow velocity increase. The results are compared with the numerical approach and gives good agreement of used technique

The main aim of this research is to find the most suitable correlations which relating the rheological properties of invert emulsions of different densities (2.2, 2.4, and 2.5 gm/cm3) with temperature and pressure. According to that an theoretical study has been done to predict these correlations, depending on Rosenbrock optimization technique. Rheological properties such as plastic viscosity, and yield point data at different temperatures and pressures were selected from literature. New correlations were predicted which show firstly the effect of temperature on the plastic viscosity and yield point, and secondly the effect of pressure on these rheological properties. The results indicated that there are a correlations with high accuracy which can represented the effect of temperature and pressure on the rheological properties of invert emulsions (both plastic viscosity, and yield point) for each density which show that the rheological properties of invert emulsions decreased with increasing temperature and increased with increasing pressure. New empirical formulae for the combined effect of temperature and pressure on the rheological properties of invert emulsions for different densities have been developed by using Rosenbrock optimization technique.

Design of forming tool (Extrusion die) is one of the most important factors that affect the mechanical properties of formed products (specific tension) . Other factors as die profile along ,friction,temperature and reduction of area will produce aspecific deformation mode that affect on the mechanical properties of the extrusion product . The aim of this research to study the efficiency of extrusion dies on the basis of both theoretical design concepts (CRHS, CMSR) and industrial concept (TAPER ) . This research studied final tension property of the extrusion products through these dies with theoretical concepts and industrial concept .The reduction of area of all this dies is (50%) . The results show that extrusion die (CMSR) is the most efficient die in design ,at the same time ,design of taper die show lost efficiency .

The international companies compete between them to gain the markets; these companies are facing many challenges to ensure stay in competition market. Now the industrial organizations concentrate on customers’ needs and they work seriously to satisfy the customers. So the industrial organizations continuously search about competition characteristics and improve the current products quality to ensure stay in the markets. Today quality considers the important tools that ensure to the company gains the market, competition and customers loyalty. one of the most way to improve quality of products or services is apply the seven basic tools of quality , these tools help the industrial organization to understands and improves the production processes by collect information ,generate ideas ,improve , analysis and evaluate the production processes. The main objectives of quality tools are to prevent or minimize production of defects products. In this research we apply two tools of quality; Pareto chart and cause and effect diagram to diagnosis and to find the defects types and causes for one products of the state company of leather industries; the female shoe that produce in factory No (1) , we find that the largest defects 55% (Vital Few )occur in molding operation(Withdraw the leather) and this defects can be avoid be increase the workers attention and also be maintains the cutting tools of leather . There are many causes that cause defects in female shoes such as; workers, machines, leather raw material and work environment. the workers consider the largest source of defects because most of factory operations based on the worker accuracy ,quality of work, so solve these problems are possible by concentration the effort towards the factory workers to improve the product quality , specially, the company products have good reputation in the Iraqi market

This research aims to evaluate of using the crushed gravel of Kerbala quarries in product self compacting concrete (SCC) , American method (ACI) and (Common mix design method for SCC) are used to design the concrete mixes, the mix proportion of these mixes is (1:1.8:2), and water cement ratio is (0.5) the work involves four mixes, the first without any admixture ,and in the another mixes use limestone powder of (100Kg /m3) and superplasticizer (KUT Plast RNA) by (2, 4 , 6 ) % of cement content respectively. Slump test, Slump flow test, L-Box test and V-funnel test are using to determine the workability of all mixes , the values of slump and slump flow are (80, 230, 420, 760) mm, the blocking ratio (H2/H1) value is (0.83) and the flow time through the V-funnel is (11) seconds respectively, the mechanical properties studied in this work are compressive strength by using cubes of (100*100*100) mm, with average value of nine spacements are (19.4, 23, 26.5, 30.2), (27.6, 38.2, 41, 56.7) and (32.3, 45, 57.6, 68) N/mm2 of (7, 28, 90) day ages respectively , and splitting tensile strength by using cylinders of (150*300) mm, with average values of six spacements are (4, 4.5, 5.9, 7.4), (4.5, 5.2, 6.4, 8.3) and (4.7, 5.5, 6.7, 8.4) N/mm2 of (28, 56, 90) days ages respectively . The results indicate that the fourth concrete mix with using (6%) of superplasticizer gives a self compacting concrete

The present work is devoted to experimental measurement of combustion gasses and calculation of the energy losses with leaving gasses during exhaust nozzle for furnace of boiler Didacta-Italia power plant. The energy losses are presented by (1) – the comprehensive energy losses as, a – the losses energy with outlet exhaust gasses to the atmosphere, b - the fuel chemical energy which are not burned. (2) The comprehensive exchange losses due to the losses of water pipe leakage and the losses in steam or hot water leaving the boiler. By use of ORSAT device the combustion gasses are analyzed to calculate the percentage of concentration and molars of volumes of these gasses and ) , the result of calculation for the energy losses leaving with the gasses was (179.147 kj/kg) .Theoretical heat amount produced by combustion of fuel (gas oil) and the heat amount released by combustion gasses of steam in the boiler are also calculated , the difference between theme represent the steam generation unit losses .The comprehensive energy losses in steam generation unit for one Kg of fuel was (25.466 kW). Also the mass flow rate of burning gasses is calculated which was (430 kg /h).