Numerical models are used to solve the two-dimensional transient natural convection heat transfer problem in an inclined shallow porous cavity. A constant heat flux is applied for heating and cooling all opposing walls. Solutions for laminar case are obtained within Rayleigh number varied from 20 to 500 and aspect ratio for porous cavity varied from 2 to 4. A finite difference method is used to obtain numerical solutions of full governing equations. Both vorticity and energy equation are solved using alternating direct implicit (ADI) method and stream function equation by successive over relaxation (SOR) method. The results are presented for the flow filed, temperature distributions, and average Nusselt number in terms of the Rayleigh nu

In this study, the electro-hydraulic servo system for speed control of fixed displacement hydraulic motor using proportional valve and (PID) controller is investigated theoretically ,experimentally and simulation . The theoretical part includes the derivation of the nonlinear mathematical model equation of (valve – motor ) combination system and the derivation of the transfer function for the complete hydraulic system , the stability test of the system during the operation through the transfer function using MATLAB package
V7.1 have been done. An experimental part includes design and built hydraulic test rig and simple PID controller .The best PID gains have been calculated experimentally and simulation, speed control performance te

Series compensation is frequently found on long transmission lines used to improve voltage stability. Due to the long transmission lines, voltage begins to decay as the line moves further from the source. Series compensation devices placed strategically on the line to increase the voltage profile of the line to levels near 1.0 p.u.. This paper presents a novel optimum location and optimum percentage compensation value of a series capacitor as a compensation method to enhance the voltage stability and loss reduction. The proposed method is applied to a 11-bus power system.The load flow analysis using Newton-Raphson approach for the 11-bus test system was designed and tested using MATLAB 7 programming language.

This research presents a model for surveying networks configuration which is designed and called a Computerized Integrated System for Triangulation Network Modeling (CISTNM). It focuses on the strength of figure as a concept then on estimating the relative error (RE) for the computed side (base line) triangulation element. The CISTNM can compute the maximum elevations of the highest
obstacles of the line of sight, the observational signal tower height, the contribution of each triangulation station with their intervisibility test and analysis. The model is characterized by the flexibility to select either a single figure or a combined figures network option. Each option includes three other implicit options such as: triangles, quadri

In this study, a 3 mm thickness 7075-T6 aluminium alloy sheet was used in the friction stir welding process. Using the design of experiment to reduce the number of experiments and to obtain the optimum friction stir welding parameters by utilizing Taguchi technique based on the ultimate tensile test results. Orthogonal array of L9 (3³) was used based on three numbers of the parameters and three levels for each parameter, where shoulder-workpiece interference depth (0.20, 0.25, and 0.3) mm, pin geometry (cylindrical thread flat end, cylindrical thread with 3 flat round end, cylindrical thread round end), and thread pitch (0.8, 1, and 1.2) mm) this technique executed by Minitab 17 software. The results showed th

This paper deals with finite element modeling of the ultimate load behavior of double skin composite (DSC) slabs. In a DSC slab, shear connectors in the form of nut bolt technique studs are used to transfer shear between the outer skin made of steel plates and the concrete core. The current study is based on finite element analysis using ANSYS Version 11 APDL release computer program. Experimental programmes were carried out by the others, two simply supported DSC beams were tested until failure under a concentrated load applied at the center. These test specimens were analyzed by the finite element method and the analyses have shown that these slabs displayed a high degree of flexural characteristics, ultimate strength,

An experimental and theoretical works were carried out to model the wire condenser in the domestic refrigerator by calculating the heat transfer coefficient and pressure drop and finding the optimum performance. The two methods were used for calculation, zone method, and an integral method. The work was conducted by using two wire condensers with equal length but different in tube diameters, two refrigerants, R-134a and R-600a, and two different compressors matching the refrigerant type. In the experimental work, the optimum charge was found for the refrigerator according to ASHRAE recommendation. Then, the tests were done at 32˚C ambient temperature in a closed room with dimension (2m*2m*3m). The results showed that th

Reducing global warming potential (GWP) of refrigerants is needed to the decrease of ozone-depleting of refrigeration systems leakages. Refrigerant R1234yf is now used to substitute R134a inside mobile air conditioning systems. Thermodynamic properties of R1234yf are similar to R134a. Also, it has a very low GWP of 4, compared to 1430 for R134a, making it a proper choice for future automobile refrigerants. The purpose of this research is to represent the main operating and performance differences between R1234yf and R134a. Experimental analysis was carried out on the automotive air conditioning system (AACS) with 3 kW nominal capacity, to test and compare the performance of R134a with R1234yf. Experiments were accomplish

An experimental study was performed to estimate the forced convection heat transfer performance and the pressure drop of a single layer graphene (GNPs) based DI-water nanofluid in a circular tube under a laminar flow and a uniform heat flux boundary conditions. The viscosity and thermal conductivity of nanofluid at weight concentrations of (0.1 to 1 wt%) were measured. The effects of the velocity of flow, heat flux and nanoparticle weight concentrations on the  enhancement of the heat transfer are examined. The Nusselt number of the GNPs nanofluid was enhanced as the heat flux and the velocity of flow rate  increased, and the maximum Nusselt number  ratio (Nu nanofluid/ Nu base fluid)   and thermal performance factor

Electrocardiogram (ECG) is an important physiological signal for cardiac disease diagnosis. With the increasing use of modern electrocardiogram monitoring devices that generate vast amount of data requiring huge storage capacity. In order to decrease storage costs or make ECG signals suitable and ready for transmission through common communication channels, the ECG data
volume must be reduced. So an effective data compression method is required. This paper presents an efficient technique for the compression of ECG signals. In this technique, different transforms have been used to compress the ECG signals. At first, a 1-D ECG data was segmented and aligned to a 2-D data array, then 2-D mixed transform was implemented to compress the

To damp the low-frequency oscillations which occurred due to the disturbances in the electrical power system, the generators are equipped with Power System Stabilizer (PSS) that provide supplementary feedback stabilizing signals. The low-frequency oscillations in power system are classified as local mode oscillations, intra-area mode oscillation, and interarea mode oscillations. Double input multiband Power system stabilizers (PSSs) were used to damp out low-frequency oscillations in power system. Among dual-input PSSs, PSS4B offers superior transient performance. Power system simulator for engineering (PSS/E) software was adopted to test and evaluate the dynamic performance of PSS4B model on Iraqi national grid. The res

The aim of this research was to apply a numerical model capable of describing the thermal pollution in rivers. For this purpose a two-dimensional numerical model was applied for estimating temperature distribution in a river Momentum Conservation Equation and Thermal Energy Equation were used to describe the fdistribution and diffusion of temperature along the river subjected to thermal pollution point source. Furthermore the model incorporates the (k-e) turbulence model to calculate the distribution of turbulent viscosity The pressure distribution was determined using hydrostatic pressure equation. The partial differential equations were formalized and simplified to be solved using Alternative direction implicit- explicit method (ADI) w

The study presents the test results of Completely Decomposed Granite (CDG) soil tested under drained triaxial compression, direct shear and simple shear tests. Special attention was focused on the modification of the upper halve of conventional Direct Shear Test (DST) to behave as free
head in movement along with vertical strain control during shear stage by using Geotechnical Digital System (GDS). The results show that Free Direct Shear Test (FDST) has clear effect on the measured shear stress and vertical strain during the test. It has been found that shear strength
parameters measured from FDST were closer to those measured from simple shear and drained triaxial compression test. This study also provides an independent check on

A new mathematical model for three-dimensional thin-walled curved beam element of closed
section with seven degree-of-freedom per node is derived using the finite element procedure. The
seventh degree-of-freedom is to account for warning restraint effects in thin-walled closed sections.
These effects may become significant and should be fully considered in such sections for which
warping deformations are relatively large. This model considers the coupled action due to the
curved geometry of the element using its exact static behavior in the derivation of the displacement
field. Also, the modei considers the non-uniform torsional behavior of closed thin-walled sections
in cases where additional axial direct stresses a

_{The aim of this paper, is to analyze the assignment problem in industry where the constraint of allowing to allocate only one job to each machine is relaxed. Thus, splitting the job is permitted and processed by more than one machine. The problem is demonstrated with a real life case study. We solved the problem by splitting the jobs and converting lot of jobs as well as the actual hours of each machine to Standard Machine Hours (SMH). Transportation model is also suggested to overcome the problem, and the optimum solution is obtained by using POM software}

This work deals with the production of light fuel cuts of (gasoline, kerosene and gas oil) by catalytic cracking treatment of secondary product mater (heavy vacuum gas oil) which was produced from the vacuum distillation unit in any petroleum refinery. The objective of this research was to study the effect of the catalyst -to- oil ratio parameter on catalytic cracking process of heavy vacuum gas oil feed at constant temperature (450 °C). The first step of this treatment was, catalytic cracking of this material by constructed batch reactor occupied with auxiliary control devices, at selective range of the catalyst –to- oil ratio parameter (  2, 2.5, 3 and 3.5) respectively.  The conversion of heavy vacuum gas

In this paper different channel coding and interleaving schemes in DS/CDMA system over multipath fading channel were used. Two types of serially concatenated coding were presented. The first one composed of Reed-Solomon as outer code, convolutional code as inner code and the interleaver between the outer and inner codes and the second consist of convolutional code as outer code, interleaved in the middle and differential code as an inner code. Bit error rate performance of different schemes in multipath fading channel was analyzed and compared. Rack receiver was used in DS/CDMA receiver to combine multipath components in order to enhance the signal to noise ratio at the receiver.

Housing planning is one of the most important subjects in the housing sector studies. It
is wide and has many branches . .
Housing planning according to the cost and social benefit is the solution to prevent the
escalating rise in Housing shortage .
This fact is combined with which is estimated at more than three million housing unit .
And big a reduction in housing construction rate , which lead to increase the housing problem
in the country. This matter needs a clear policy from the authorities to accelerate the planning
process and to adopt that strategy to solve the housing problem in Iraq.
This strategy should adopt the principal of constructing low – cost housing complexes
through the

Experimental and theoretical studies have been carried out to study the adsorption of methane and carbon dioxide on 5A molecular sieve. Adsorption equilibrium isotherms of methane and carbon dioxide are reported for the temperature range 303– 333 K and pressure up to 2.5MPa. Experimental data were obtained using a static system for gas–solid adsorption. The Langmuir adsorption equilibrium equation gave
good predictions. Adsorption of methane and carbon dioxide on 5A molecular sieve is purely physical since the isosteric heat of adsorption was found to be equal to 14.804 and 37.218 kJ mole-1 for methane and carbon dioxide, respectively.

The aesthetic and architectural shapes of the beam-column elements may enhance the elements strength depending on the maximum and minimum bending moments effect. Therefore, the stability value of the non-linear taper member in concave configuration may be more efficient than linear taper or prismatic members. The modified stability functions will be obtained from the solution of the basic differential equation, where this basic differential equation depends on the non-linearity factor of the beam-column shape and the shape factor of the cross-sectional area. These two factors, multiplied by others, produce the modified shape factor, which affects the results of the basic differential equation solutions.

Different methods of encryption that are widely used in smart card have been presented. Because of the usefulness and widespread application of Food Ration Card throughout our country, three models of designing and simulations are developed. A comparison between the different models is done. The first model is the Food Ration Card without using any security method. The second model is the Food Ration Card with using an AES algorithm as a security method. The third model is the Food Ration Card with using RSA method. All models are implemented and simulated using  BasicCard Development kit Environment. For the first model, a Compact BasicCard version ZC1.1 is used. While for the second and third models, a Professional BasicCard versi

This paper reports the conversion of a large unsignalised roundabout (HURIYA SQUARI!) relatively close to the University of Baghdad campus to a signalized intersection. The study focused on reduction of vehicle delay and queue length at this  intersection area. During the course of this research project, two software packages for the analysis and design of isolated intersection, SIDRA (Akcelik, R.1986 and 1991) and HCS (Transportation Research Board, National Research Council 1994) were available. A trial site selected and the observed dara used in the evaluation of the SIDRA and HCS outputs. The evaluation process indicated that SIDRA produce vehicle delay, which is reasonably consistent with the observed vehicle dela

Knapsack problems are a class of common but difficult (NP-complete or NP -hard) problems. Since, it is believed that no knapsack problem algorithm can be constructed whose computation time optimality increases as any polynomial function of the problem size. There is a variety of knapsack-type problems in which a set of entities, together with their values (profits) and sizes, is given, and it is desired to select one or more disjoint subsets so that the total of the sizes in each subset does not exceed given bounds and the total of the selected values is maximized. Diploid representation and dominance operator are advanced operators that attempt to improve upon the power of traditional genetic algorithms. Pseudo Meiosis Genetic Algorithm

This article proposes a current mode inverting and non-inverting Schmitt trigger circuit, which utilizes a Current Follower Transconductance Amplifier (CFTA) and its application in square and triangular wave generators. The hysteresis of a Schmitt trigger is directly influenced by the process variations and transistor mismatches. This issue is more challenging in applications where the level of noise and disturbances is not predictable. To overcome this deficiency, Schmitt triggers with tunable hysteresis can be used as a practical solution. The suggested circuit consists of a single CFTA analog building block laterally with one grounded resistor. The grounded resistor makes the realization of the above-mentioned circuit

The cost management of cost indicators in housing projects, on the level of planning and design, is the most important quality indicators, for adoption of strategies of planning and design efficient in managing these indicators. So this research points out the need to highlight the most effective and influential cost indicators in housing projects, and to determine strategies in the management of these indicators in order to raise the efficiency of housing projects quality, to seemly the income level target group, taking into consideration the quality of housing standards, to achieve the basic requirements of housing. This paper highlights the importance of the cost  management, the types of housing cost, the method

Fiber reinforced polymers are typically comprised of high strength fibers (e.g. carbon and glass) impregnated with an epoxy (often termed the matrix). Experimental investigations of the behavior of reinforced concrete beams, strengthened or repaired by CFRP for flexural case have been presented in this paper. The experimental program consisted of 14 test beams. The study took into account strengthened and repaired cases in using CFRP; therefore, similar beams were used once for strengthening and once for repairing to make a comparison between them. All beams had been tested in a simply supported span and subjected to two-point loading while the main variable is the quantity, distribution and location of CFRP. The beams included additiona

Shallow foundations are usually used for structures with light to moderate loads where the soil underneath can carry them. In some cases, soil strength and/or other properties are not adequate and require improvement using one of the ground improvement techniques. Stone column is one of the common improvement techniques in which a column of stone is installed vertically in clayey soils. Stone columns are usually used to increase soil strength and to accelerate soil consolidation by acting as vertical drains. Many researches have been done to estimate the behavior of the improved soil. However, none of them considered the effect of stone column geometry on the behavior of the circular footing. In this research, finite ele

Theoretical and experimental investigations have been carried out on developing laminar
combined free and forced convection heat transfer in a vertical concentric annulus with uniformly
heated outer cylinder (constant heat flux) and adiabatic inner cylinder for both aiding and opposing
flows. The theoretical investigation involved a mathematical modeling and numerical solution for
two dimensional, symmetric, simultaneously developing laminar air flows was achieved. The
governing equations of motion (continuity, momentum and energy) are solved by using implicit
finite difference method and the Gauss elimination technique. The theoretical work covers heat flux
range from (200 to 1500) W/m2, Re range from 400 to 2000 an

Every year, millions of tons of waste glass are created across the globe. It is disposed of in landfills, which is unsustainable since it does not disintegrate into the environment. This study aims to produce reactive powder concrete by using recycled glass powder and determine the influence on the mechanical properties. This study investigated the effect of partial replacement of cement with recycled glass powder at two percentages (0, 20) % by weight of cement on some mechanical properties (Fresh density, Splitting tensile strength, Impact Strength, and voids%) of reactive powder concrete containing 1 % micro steel (MSRPC). Furthermore, using steam curing for (5 hours) at 90 degrees celsius after hardening the sample directly, RPC was

Efficient operations and output of outstanding quality distinguish superior manufacturing sectors. The manufacturing process production of bending sheet metal is a form of fabrication in the industry of manufacture in which the plate is bent using punches and dies to the angle of the work design. Product quality is influenced by plate material selection, which includes thickness, type, dimensions, and material. Because no prior research has concentrated on this methodology, this research aims to determine V-bending capacity limits utilizing the press bending method. The inquiry employed finite element analysis (FEA), along with Solidworks was the tool of choice to develop drawings of design and simulations. The ASTM E290