Engineering and Technology Journal

The present research intended to determine thermal properties (thermal
conductivity, thermal diffusivity and specific heat) of concrete manufactured by recycle waste of clay brick and thermostone for using it as aggregate after crushing process. For this purpose, three concrete mixes were prepared one of them using crushed clay brick as aggregate and two others were used crushed thermostone as aggregate too, these three mixes compared with reference normal concrete mix.
Specific heat was measured by using semi-adiabatic calorimeter method whereas thermal diffusivity was measured by using heating-cooling system. Thermal conductivity was obtained by multiplying the thermal diffusivity, specific heat and density. From experimental laboratory work, it was concluded that the thermal diffusivity increase with concrete density increment, but the specific heat was decreased with concrete density increment. Thermal conductivity had a linear relationship with thermal diffusivity. Mixing ratio also had an influence on thermal properties of concrete.

The properties that make plastic of direct interest to designers and engineers are its good strength to weight ratio, low manufacturing installation costs, and high durability. The strength of polymers is known to be sensitive to temperature and this generally limits their use under service temperatures. The present work addresses the effect of temperatures ranging from 0 to 70 on the shear properties of high-density polyethylene (HDPE) and polyvinyl chloride (PVC) materials. The results show that Yield stress increase with temperature by (15.4%) for HDPE and the temperature has no effect on yield stresses of PVC.
The modulus of elasticity varied in each temperature for both materials selected and the maximum shear strength, however, showed a slight increase in this temperature range by (1.4%) for HDPE but slightly decrease by (2%) for PVC. Shear rupture and elongation reduced by (0.02%) with increasing temperature by (1 °C) for both materials .Ductile fracture is observed to be the controlling failure mechanism at all temperatures of interest for both material and no data were recorded at 70 due to distortion of all specimens in this temperature selected.

This paper deals with the problem of optimum design of reinforced concrete flat slabs by genetic algorithm. Four case studies are discussed; flat slabs with and without edge beams, and, flat-plate with and without edge beams. The cost function represents the cost of concrete, steel reinforcement, and formwork. The design variables are: the effective depth of the slab, dimensions of drop panel, the area of flexural reinforcement at the critical sections of slab, and of edge beams. The constraints are taken on slab dimensions, and area of steel reinforcements. The results showed that the optimum ratio of (effective depth /span length) are within the ranges (1/39-1/27) for flat slabs without edge beams, (1/43-1/30) for flat slabs with edge beams , (1/30-1/23) for flat-plate without edge beams and (1/35-1/25) for flat-plates with edge beams. It is also found, that for same span length, the flat slab without edge beams is more economical slab types.

This paper proposes a novel method for controlling the output DC-link voltage of the Z-source inverter foradjustable speed drive applications. An adaptive neuro-fuzzy controller is used to control the DC-link. The novelty of the proposed controller is the direct feedback from the DC-link, which is a discontinuous (chopped) signal, without any additional estimation or peak detection circuits. Where,this discontinuous feedback can't be used in conventional controllerswithout additional circuits. Design and simulation of the proposed control system are illustrated in this paper. Simulation results give excellent performance of the Z-source inverter with ripple free DC-link voltage. The robustness of the proposed intelligent controller is demonstrated for different output voltage commands. The response of the DC-link voltage, output AC voltage, AC current and speedfor 20% and 40% input voltage sag is investigated.

The aim of this paper is to study the corrosion rates and porosity of industrial paints used for car body coating. Seven types of industrial paints were used for car body structuresincluded 2K clear coat (Lacquers), Auto Paint 2K top coat, TS 16949 (Easi coat), Clear coat (Palinal), National Numix top coat, DENSO and ICI 2K solvent based (Tinters P420) were tested and studied using the electrochemical impedance spectroscopic (EIS) method. The liquefaction potable water solution was used as electrolyte for test. The obtained results showed that the Palinal paint has high impendence and lower porosity while TS 16949 (Easi coat) shows lower impedance and high porosity. Other types showed moderates values. Microscopic inspection of the surface coatings after EIS test showed that most paints had pitting corrosion except Auto paint shows blisters.

This work proposes a close form solution algorithm to solve the inverse kinematics for a five degree of freedom (DOF) robot manipulator, close form solution is preferable to numerical solutions because analytical ones yield complete solutions and are computationally fast and reliable. The motion path of a robot arm is calculated using the geometric analysis. The proposed algorithm is verified using developed simulation modules. Computer simulation is conducted to demonstrate accuracy of the proposed algorithm to generate an appropriate joint angle for reaching desired Cartesian coordinate. The algorithm has been tested yield fair, which have also compared with the robot arm's actual reading.

Galvanic and free corrosion experiments on carbon steel-copper couple in 3% H2SO4in the presence of NaCl salts were carried out under different operating conditions. The effect of temperature, agitation speed, and air bubbling (O2 concentration) on the free and galvanic corrosion was studied and discussed. The galvanic corrosion was investigated by both weight loss method and by determining the galvanic currents using zero resistance ammeter (ZRA). The results revealed that increasing temperature leads to increase the galvanic corrosion rate and also the free corrosion rate of each metal. Increasing agitation velocity enhanced the galvanic corrosion rate in a manner depending on temperature. The presence of air bubbling increased the corrosion rate and galvanic currents at low air pumping rate, while, at high pumping rate, air bubbling decreased the corrosion rate.

The structural behavior of perforated composite web plate girders under shear loading is studied. Five steel plate girders have been tested. Two of them are reference girders, not perforated and perforated. The perforated webs in the three other girders are strengthened with carbon fiber reinforced polymer (CFRP) laminates in different patterns. The diameter of the central circle opening is 300 mm, where is 60% of the web depth. It is found from the experimental work that the ultimate shear load for the perforated composite web plate girder is higher than the reference perforated girder in a range of 100% to 134% depending on the orientation of the fiber in CFRP laminates. Through the experimental results, new formulas are presented to predict the ultimate shear load of perforated strengthened steel girders by CFRP laminates. A nonlinear finite element analysis is carried out for the tested plate girders using the package software program (ANSYS V.14.5). The analytical results contain the distribution of VonMises stresses, which is useful to have a better understanding to the results obtained from the experimental tests.

The coating thickness is an important factor to evaluate the coating quality and determining the properties of the hot-dip aluminizing (HDA)coating. In the present work, a hot dipping pure aluminum (99%) on stainless steel (AISI 303) rods was carried out for different diameters of rods (8, 10 and 12mm) and different lengths (250 and 500 mm) at different aluminizing conditions of temperature and time. The dipping temperature was set to 700, 740, 780, 820 and 860℃ .The dipping time was set to 1, 2, 3,4 and 5 minutes. A response surface methodology (RSM) using a central composite rotatable design (CCD) for a 2³ factorial, with 5 central points and α = ±2 approach, based on the experimental data, was used to obtain the optimum modelto get the best thickness of coating and the best conditions of dipping. A 2nd polynomial model was obtained with a confiding percentage of 95%.Analysis of the experiments using RSM indicated that 807℃ and3minare optimum dipping conditions for hot-dip aluminizing process with corresponding thickness of coating layers of 134 μmto Al layer,62.9 μm to intermetallic compound (IMC) layer and 197μm to total coating layer.

In this work, the influence of different heat treatments on the mechanical properties and fatigue life under low cycles of wrought 7075 aluminum alloy was experimentally investigated. The heat treatments included peak ageing (T6), over ageing (T73) and annealing (O).The flat fatigue specimens were subjected to constant reverse bending load. The tests were performed at the laboratory environment with a frequency of 23.6 Hz andat a stress ratio (R) of -1.For each temper, strain-life graphs were obtained for specimens with notches in the form of central cylindrical holes made by drilling. The fatigue resistance of specimens with notches was comparedto the results for notch-free specimens. It was observed that the presence of a stress raiser, such as a drilled hole, lowers the fatigue life for all tempers. However, the notch sensitivity of the fatigue life was different for each temper. The fatigue crack growth rate of T73 and annealed temper was investigated; the results showed that T73 treated sample exhibits higher crack growth resistance. Paris` equation was derived for each temper.

This paper presents an orientation filter using complementary filter applicable to low-cost sensors based on micro electro-mechanical system (MEMS). The MEMS implementation incorporates magnetic distortion and gyroscope bias drift compensation. The filter uses a quaternion representation, allowing accelerometer and magnetometer data to be used in an analytically derived andoptimized gradient-descent algorithm to compute the direction of the gyroscope measurement error as a quaternion derivative. The benefits of the filter are: (1) low scalar arithmetic operations for each filter update, (2) It is effective at low sampling rates; e.g. 10 Hz and (3) It contains adjustable parameters defined by observable system characteristics. The Performance was evaluated empirically using a commercially available orientation sensor and reference measurements of orientation obtained usingan accurate servo motor (resolution <0.3 degree). A simple calibration method is presented for the use of the electric-mechanical measurement equipment in this application. Results indicate that the filter achieves levels of accuracy exceeding that of the Kalman-based algorithm; < 0.821◦ for static RMS error and<2.093◦ for dynamic RMS (Root Mean Square) error. The implications of the low computational load and ability to operate at low sampling rates use of MARG(Magnetic, Angular Rate, and Gravity) sensor arrays in real-time applications of limited power, processing resources or applications that demand extremely high sampling rates

Electric discharge machining(EDM) is one of the nonconventional machining process which has been used in manufacturing complex shapes on hard material that are difficult to cut by conventional processes, especially, die casting, parts of aircraft, medical equipment, automobile industries. Powder mixed electric discharge machining(PMEDM), has emerged as one of the advanced techniques in the direction of the enhancement of the capabilities of EDM. The objective of the present research is to study the influence of process parameters such as peak current, pulse on time, manganese,aluminum, and aluminum-manganese mixing powder concentration on machining performance of different types of die steel (AISID3,AISID6,H13)with round copper electrode(20 mm diameter) on machining performance. Experiments have been designed using Taguchi method. Taguchi L27 orthogonal array has been selected for five factors 3 levels design. The machining performance has evaluated in terms of metal removal rate (MRR).It is found that manganese powder concentration mixed in dielectric fluid significantly affect the machining performance, maximum (MRR) is obtained at a high peak current(12 A), pulse on(200µs), and (4g/L) concentration of manganese powder,the optimum MRR is 17.56mm3/min with percent of error about 5.61% compared with the Experimental value.

In this work, the effect of sodium chloride (NaCl) powder addition with different amounts on microstructure and mechanical properties of Al-12 wt. %Si alloy was investigated. In this technique, modification by NaCl was used because of its availability and low price comparing to other modifiers such as Sr and Sb. A 1000 °C as pouring temperature of molten alloy was used. The present results showed that there is a significant change in the mechanical properties and microstructure compared with unmodified alloy. The optimum properties were found by adding 0.5wt% NaCl to the alloy, and also the modification of microstructure alloy. Mechanical properties and microstructure of Al-12wt. %Si alloys that poured from 1000 °C with NaCl additives were compared with the corresponding alloys but at 800 °C pouring temperature, it is found that alloys poured from 1000 °C have best properties as compared with the same alloys poured from 800 °C.

This paper is to analyze the impact of optical signal degradation on the quality of optical fiber communication systems, and enhance the way of reducing the signal degradation mechanism. In this paper, different investigation has been carried out in order to: Investigate the stability of various modulation formats to the effects of chromatic, polarization mode dispersion and nonlinear effects. And achieve the desired interest in the optical communications from the viewpoint of improving the stability to the dispersion, and find the optimum receiver bandwidth at which the system error rate is minimized. And find new ways of compensating chromatic dispersion in communication systems at 40 Gb/s. And find new ways to increase the range of transmission in a communication system transmitters based on semiconductor lasers with direct modulation.

ABSTRACT
The stone column material is one of the main controlling parameters in the design of stone columns. It is shown to be affecting the stiffness of the stone columns and hence settlement of the treated soil. Severalmaterials with friction angles of stone column material used to reinforce weak soil as stone columns. Finite element analyses were carried out to evaluate the settlement of soft clay reinforced with stone columns using 15-noded triangular elements in Plaxis 2D v8 software. An analysis carried out using Mohr-Coulomb’s criterion model for stones columns and soft soil clay. The numerical results from the FEM provide calculated settlement, excess pore water pressure and lateral bulging of the stone column. It was found that friction angle 40o reduces the total settlement and lateral bulging to approximately 0.038m, 0.00086mrespectively of that of reinforced clay with friction angle of crushed stone 27.5o.

The Multiple Signal Classification (MUSIC) algorithm is the most popular algorithm to estimate the Angle of Arrival (AOA) of the received signals. This algorithm is based on the calculation of thermal noise Eigen values and their corresponding Eigen vectors and then using them in a matrix form in the MUSIC direction finding (DF) formula. All researches in this field assumed isotropic sensors for array antennas. But for practical application in V/UHF, a practical antenna is to be used like half-wave dipole or any type of wired antenna. When MUSIC algorithm is tested with a well-known half-wave dipole which has a directive pattern in E-plane, a false reading is raised from the two angles coincide with the dipole element axis. It is found that the MUSIC algorithm does not take into consideration the nulls that result from the pattern multiplication between array factor AF (θ) and element pattern f (θ). This paper suggests an alternative approach for angle of arrival estimation. A new DF formula is derived. The suggested approach is based on the use of modified array processor in conjunction with minimum noise variance constrain algorithm as an angle of arrival estimator in spite of interference canceller as it is used for. The results show that the alternative approach gives a quite good result without any false reading or any degradation in the performance of AOA estimation.

This paper presented a three-dimensional continuous autonomous chaotic system, modified from the Arnold system which has a single product termin each equation of thesystem; therefore it's different from Arnold system and other existing system. This system has nine parameter (i.e. A,B,C,D,E, and F) which gives a more flexibility in generation chaotic behavior throughout these parameters. Basic properties of the presented system were analyzed by means of Lyapunov exponent spectrum, Poincar'e mapping, fractal dimension, power spectrum and chaotic behaviors. Theoretical and numerical analysisprove that the system shows chaoticbehavior. Furthermore the cited chaotic system was implemented in robotics field for coverage area purposes, where it's used to generate chaotic motion for mobile robot that's guarantee ofscanning the whole connected workspace as an example of advantage of this system

The present work represents an investigation for the pollutants emission when adding water to air in a continuous combustion chamber. Direct water injection into the chamber with water/fuel ratio up to 0.8, as well as, humidifying the inlet air with water prior to the chamber by changing humidity between 20 to 100%, has been examined at different equivalence ratio with gas oil fuel. The results with fuel droplet size of 80µm and Φ=0.8, show that when water directly injected, NOx and soot will decrease by 53% and 56.6% respectively. Nevertheless, CO and UHC are to increase by 108% and 84% respectively. On the other hand, when inlet air has humidified, the decrease in NOx and soot will be 17.15% and 17.94% respectively. But, CO and UHC show an increase of 13.5% and 8.47% respectively.

In this work, reverse froth flotation technique has been adopted to upgrade the Iraqi phosphate ore from Akashat deposit as an alternative method to the existing calcination method. Prior to flotation experiments, a feed flotation was prepared by washing and desliming operations on 300 and 75 µm ASTM sieve opening to eliminate fine materials. In flotation experiments, the effect of the parameters, collector (oleic acid) quantity, phosphate depressor (sodium sulfate) quantity, solid%, pH value of the pulp (using H2SO4) and flotation time were investigated. The experimental results obtained showed that the flotation method applied has managed to beneficiate Akashat phosphate ore to the acceptable level for commercial utilization. The phosphate concentrate obtained under the optimum conditions (1kg/t of oleic acid ,10kg/t of sodium sulfate, 30% solid concentration, 6.5 pH and 3 minutes for flotation time) containing 32% P2O5, 0.5% MgO and CaO/P2O5 ratio less than of 1.6% with a recovery of 93%.

The Curriculum does not arise from nothing ... but there are many foundations or determinants that affect them, that gain the utmost importance when Designing ,Evaluating &Organizing the Curriculum and it’s a multi-overlapping determinants, and the fact that today's world is passing through a stage of scientific development and massive technological advances, this stage is Known by the scientific and technological Revolution, which added to the human civilization huge toll of knowledge in many areas, that increasing in quantity and quality day after day, and while the educational or academic institutions is a social institutions created by the community for the continuation and preparation of individuals to carry out their responsibilities in it, and also are considered a tributary which supplies the community with different scientific persons that advance the reality for the better, many efforts have been made in the research and studies in the field of evaluation and the quality of the Curriculum in academic institutions, given the escalating emphasis on the concept of Reliability and Quality in the educational institutions in general and higher education in particular, such as universities and research centers. And in considering the above statements , the research seeks todiagnose or explore the weaknesses in the quality of the curriculum in one of the engineering colleges departments after being selected the University of AL-Nahrain, where was the workplace of the researcher and after his contribution in the preparation and study of the self-Assessment reports in one of its scientific Department, that was the Architectural Department ,so it has emerged the need for exploring the weaknesses in the curriculum after doing the self-Assessment reports according to CRITERIA of (ABET) for Reliability . The research has selects some academic years that was (2011-2012) and (2013-2014) to review the self-Assessment reports pertaining to curriculum, which has been adopted and available in Department Documentation section which has been possible for the researcher to make use of them. The research concluded that the Curriculum for those years had suffered from a certain weakness in some factors that have been drawn from the case study process, which we can summarize it in the lack of availability of textbooks and references that allocated to support and enhance the vocabulary of subjects, in addition to the educational potential and laboratories were not suitable.. as well as the limited availability of lecture halls and its supplementary educational equipment which impacted directly on the quality of the implementation of the Curriculum ,the research has proceeds a set of recommendations, including the need to pay attention in addition to avoiding the weaknesses diagnosed towards maintaining the quality of the performance and implementation of the Curriculum on one hand, it has recommended the need to activate the lecture methods appropriate to vocabulary for different subjects, to maintain quality performance and implementation of the Curriculum to deal with the diagnosed weaknesses on the other.