Journal of Engineering and Sustainable Development (JEASD)

In the present work, a numerical and experimental investigation is carried out to evaluate the performance of a helically coiled tube heat exchanger with a wire coil insert. Experimental work included the design of wire coiled and inserted into a vertically positioned plain copper helical tube heat exchanger. The effects of wire coil insert with different parameters on heat transfer and friction loss in the helical tube were examined with Dean numbers ranging from 700 to 2000. The experiments of coiled wire were performed, firstly with three different pitches (P= 15, 20, and 30)mm with a constant circular cross-section(a=1mm), secondly with a different cross-section (circular and square) at a constant pitch of 15mm, and thirdly with two different square wire thickness (a =1, 2) mm at constant pitch 15mm. The numerical analysis was carried out to simulate the flow and heat transfer in a helical coil tube with a wire coil insert at pitch (15mm) with different flow rates by using ANSYS FLUENT package 14.0. The experimental results showed that the use of tubular leads to a considerable increase in heat transfer and friction loss over those of a smooth coiled tube. The Nusselt number increases with the increasing of Dean number and the reduction in pitch for wire coils. The coiled square wire provides higher heat transfer than the circular one under the same conditions. New empirical correlations have been developed to predict the Nusselt number of the helical coil heat exchanger...

The main purpose of this experimental study is to investigate the behavior and strength of self-compacting reinforced concrete corbels with and without steel fibers. The program included (10) specimens, in which the shear span to effective depth ratio (a/d), the amount of steel fiber (Vf), and compressive strength(f'c)of self-compacting concrete were varied. All specimens had the same length, thickness and main reinforcement and they were subjected to concentrated vertical loads only.It was found that the addition of steel fibers delays the formation of the cracking of fibrous corbel relative to nonfibrous corbels and the cracking load and ultimate load for Normal strength self-compacting concrete(NSCC) corbels increase by 31.5% and 25.3% when the volume of steel fibers increases from 0% to 0.4%. While the cracking and ultimate loads increases by 7.3% and 3.1% when the volume of steel fibers increases from 0.4% to 0.8% and the increase in volume of steel fibers from 0% to 0.8% results in increasing the cracking load and ultimate load by about 41.1% and 29.1% respectively.

Self-compacting concrete (SCC) is a relatively new generation of concrete that is characterized by the liquid nature that makes it appropriate for cast narrow members such as deep beams without vibration. The work aims to investigate the behavior of SCC deep beams and evaluate their shear capacity especially when steel fibers are used in their construction. The experimental work includes testing twelve reinforced concrete simply supported deep beams cast using self-compacting concrete (SCC) with steel fibers to evaluate their shear behavior and strength. All tested beams have dimensions of (100×330×1050) mm and have been subjected to two-point loads. The parameters considered are shear span to effective depth ratio (a/d), concrete compressive strength (fʹc), and steel fiber volumetric ratio (Vf). Test results indicated that the increase in (a/d) ratio from 0.6 to 1 leads to decreases in cracking and ultimate shear strengths by average ratios of 25.1 % and 20.6 % respectively. Increasing (fʹc) to twice the original value leads to increases in the cracking and ultimate shear strengths by average ratios of 13.9 % and 48.1 % respectively. Using steel fibers in SCC deep beams improves cracking and ultimate shear strength by average ratios of 33.1 % and 11.4 % respectively when 0.4 % of steel fibers are used while they improve these shear strengths by average ratios of 64.4 % and 23 % when 0.8 % of steel fibers are used...

In this paper, a novel design of a heptagonal slot antenna is proposed to be used for ultra-wideband (UWB) applications. This antenna has a heptagonal slot with suitable dimensions on the lower side of a dielectric substrate which represents the ground plane, and asymmetrical slant cut ends microstrip line on the upper side of the substrate. In order to cover the entire bandwidth that was specified for UWB applications, a bevel rectangular with a rectangular notch cut tuning stub is used to enhance the coupling between the heptagonal slot and the taper microstrip feed line. Several kinds of techniques are used to improve the design of the proposed antenna such as; adjusting the gap between the tuning stub and the lower edge of the heptagonal slot, adjusting the feed position point of the tuning stub, adjusting the end cut angle of the microstrip line and bevel angle of tuning stub. The radiation characteristics of the proposed antenna such as radiation pattern, gain, and impedance bandwidth is investigated and found to be accepted over the whole operating bandwidth. The proposed antenna also shows good time domain characteristics and has a linear phase over this band giving less distortion of the received signal.

In this study, Impact Acoustics parameters obtained from received sound generated by the impact on reinforced concrete slab surface were investigated to develop an evaluation system of flaws in concrete. As Impact Acoustics parameters, frequency distribution was employed. In addition to the experiment, a three-dimensional FEM analysis was carried out to understand the theoretical background of the parameters. The results of the FEM analysis showed good agreement with experimental ones. From analytical and experimental results, it was likely possible to estimate flaw size using the relation between the resonance frequencies of impact sounds and flaws diameter.

In this research, experimental investigations have been carried out to assess the effect of partial replacement of fine aggregate by crushed concrete passed through a sieve size of No. 4.75 mm on workability, splitting tensile strength, and compressive strength of recycled concrete at 7 and 28 days curing periods. Two sets of fine aggregate have been used, the first set containing salts in conformity with the Iraqi Standard Specifications and another set not in conformity with the Iraqi Standard Specifications. The fine aggregate is replaced with crushed concrete in various percentages ( 25%, 50%, 75%, and 100%), while 0% represents the control. Results showed that by replacing 100% of crushed concrete after 28 days of curing, the compressive strength has increased by 79% from the compressive strength of the control mix, while the splitting tensile strength has decreased, reaching 24% of the splitting tensile strength of the control mix.

his paper presents a scheme of serially concatenated codes. It is formed by Bose Chaudhuri Hocquenghem (BCH) as outer code and Low-density Parity Check (LDPC) inner code in order to real-time applications by getting rid of the delay time stem from a large number of iterations of LDPC decoder. Also analyzing the performance of each code individually by several example simulations using Matlab version R2012a tested by Additive White Gaussian Noise (AWGN) channel model with Binary Phase Shift Keying (BPSK) modulation to pick up appropriate parameters for this purpose. The proposed approach presents a high performance and reduces the Bit Error Rate (BER). Proposed parameters get nearly to zero BER at a very low Signal to Noise Ratio (SNR).

An experimental investigation has been carried out on the microstructure, microhardness distribution, and corrosion behavior of weld butt joints of 6061 T6 aluminum alloy. Arc welding processes by tungsten inert gas (TIG) have been carried out on a Rolled sheets of 4mm thickness to obtain many welding joints with dimensions of (100 *50* 4)mm using ER4030 (Al Si5 ) as filler metal and argon as shielding gas. The other parameters were: welding current 180 amperes, voltage 20 volts, filler rod diameter 1.2 mm, welding speed120 mm/min, gas flow 20 L/min and two passes of the weld All welded pieces were tested by X-ray radiography and faulty pieces were excluded. The joints without defects were used to prepare many specimens for corrosion tests by the dimensions of (15*15*3) mm according to ASTM G71-31 then Optical microscopy was used to observe the welded joint microstructure. The corrosion test was implemented by using potential static polarization measurements in seawater 3.5%NaCl at a temperature of 25°C, and different velocities (1, 2, and 3) m/min. The potential of the circuit was determined by an open circuit depending on AL in electrochemical series after that the rate of the cell’s current is changed due to 100± (m v). The obtained results by the Tafel equation show that velocity contributed to increasing the corrosion resistance of 6061 T6 Al alloy for all specimens and TIG weld joints give low corrosion rates than the base metal because of changes in microstructure in the weld zone.

The present study aims to investigate the effect of adding discrete coiled wire to enhance the heat transfer in the heat exchanger. The coiled wire used in experiments was made from steel circular cross-section wire with (b = 4 mm) diameter. The outer coil wire's diameter was (B=36.5 mm) and length after been winding is (l = 100 mm), the discrete distribution of coil wires, by different spacing (S) between them with (S/l = 0.22,0.57 &1.2), which require to distribute 10, 8 & 6 coiled wires along test section respectively, were considered in the experimental study. The experiments have been carried out at constant heat flux rate and different flow rates of air that started from (Re=6000) and increased gradually to reach the following Re. (7500, 9000, 10500, 12000 and 13500). The results show that the use of the S/l=0.57 results in the augmentation of pressure loss around 33.2% higher than that of the S/l=0. In addition, it can be found that for using coiled wire turbulator with spacing ratios(0, 0.22, 0.57,& 1.2 ), the improvement of average heat transfer rate is, respectively, about 112%, 119.3%, 141.3%&132% higher than those the plain tube while the friction factor is 300%,392%,432%, and 322% times of the plain tube.

This study includes the behavior of lateral earth structures constructed on gypseous soil, wherein in some cases, we are forced to construct such heavy structures over such collapsible soil which may cause severe damage to the structures constructed. To recognize such a special case, a locally manufactured laboratory model was designed for this study. The model includes a thick and stiffened inside, rectangular plastic container (800*500*400mm). The soil used was natural gypseous soil with 5%gypsum content as a reference. additional gypsum percentages were mixed with the 5% gypseous soil reaches (25%, 40%, and 60%). The gypseous soil was compacted to 18kN/m3 density and placed at the lower portion of the container. A gravity precast concrete structure was prepared and placed over the collapsible soil. Highly permeable granular soil was placed beside the lateral gravity structure. Dial gauges were fixed at the top and beside the lateral concrete structure to investigate the vertical and horizontal deflection of such structures at dry and upon wetting by water from a special device manufactured locally, to simulate the rainfall of water from the top of the model, as in nature. The vertical and horizontal movements of the concrete wall are totally random, that is due to the uneven settlement of the wall resting on gypseous soil especially after 24 hours of continuous flooding of water because of fluctuation of water between soil particles and high dissolution of gypsum may have happened after this period due to leaching process and cavity formation ...

A series of experiments was conducted to evaluate the impact of diesel fuel types that are produced in Iraq and compared with other special types of Ethanol Blended Diesel Fuel. The testing was carried out on a four-stroke single-cylinder direct injection diesel engine under different speeds and loads in the internal combustion engine laboratory, department of machines and equipment, Baghdad Technology Institute. Five types of diesel engine Fuel included Daura, Basra, Beji local Fuel, and two biodiesel Fuels 10%Ethanol Blended Diesel Fuel, and 8%Ethanol Blended Diesel fuel, four levels of engine speeds included 1100, 1600, 2100, and 2600 rpm, and five levels of torques included 2, 4, 6, 8 and 10 Nm were used in this study. Mathematical relationships and computerized programs (ECA 100, VDAS) were used to calculate the performance parameters of the engine which included brake specific fuel consumption, the exhaust emissions included nitrogen oxide, and carbon monoxide and carbon dioxide were measured by using the exhaust gas analyzer type FLUX-2000-4. The study shows that the Beji fuel recorded the highest level of bsfc with variable torque and 8% blended is the highest value with variable speed followed by the other types of fuel. Basra has the greatest value of η_Ith at variable speed, 8% blended has a higher value of η_Ith with variable torque. Daura fuel type recorded the lowest values in emissions than the other types with variable speeds and torque reach to 29.89%, while recorded increasing on indicated thermal efficiency 11.29%.

In this research, modification of the pinhole apparatus is made as required by the specification of the American Society for Testing and Materials (ASTM D4647 – 93)[3], which works on the basis that distilled water is passed horizontally under the influence of the flow of hydraulic amount (50 mm) through a small hole diameter (1 mm) in the soil sample. The nature of the solution, which passes through the sample under the primary head (50 mm) gives an index through which a principle to distinguish between dispersive and non-dispersive clays, where the flow of clay diffuses dark and increasingly hole diameter that operate in the sample quickly resulting in an increase in the flow rate. The apparatus has been modified to take into consideration any angle with the horizon (from zero up to 90o) and thus can represent cases of flow closer to reality, as the standard apparatus is applicable to prove horizontally, i.e., it is assumed inevitably flow horizontal (horizontal flow) and the direction perpendicular to the layers of the soil. Since the primary application to pinholes is in the earth dams, the flow of water through the earth dam rarely is horizontal. So the current development represents more accurate practice. In addition, the modification included a method to prepare the sample in the compaction model in a manner similar to a standard compaction test when the moisture content and dry density are required. This required the use of a pipe pushed in the compaction mold...

In this research work, a polyester composite material was prepared to contain a matrix which is a polyester resin and reinforced with (15, 25, 35, and 45) (wt %) of alumina particles phases (crystal structure & amorphous). All samples were prepared according to the standard measurements. Mechanical tests were done for the polyester composite materials to calculate the compressive strength and hardness, and the results showed a significant improvement in the properties of the polyester composite material reinforced with alumina with phase crystal (corundum-α), also noted the positive effect of the increase in the weight of the particles on the properties of the polyester composite material with that this increase has given better results.

This work focuses on the effect of electrodeposition of nickel on corrosion behavior of mild steel substrate with ultra-fine Al2O3 and SiC using electroplating technology. The experimental results exhibited the substrate microstructure was sensitive to both current density and temperature. Grain growth was increased with increasing each current density and temperature and thereafter decreased. Optimal values were 0.2A/cm2 and 45°C, respectively. The concentration of each Al2O3 and SiC were essential to electro-deposition, it was found at 4gm/l after the traditional weight loss technique was performed, it was found that the corrosion rate of Ni and Ni- Al2O3 was deceased with exposure time in 3.5% NaCl solution whereas Ni-SiC exhibited higher corrosion rate. the addition of Al2O3 inhibited corrosion in acid solution.

In this study Rainstorm hydrograph peak discharge and unit-hydrograph peak discharge in small basins were calculated and evaluated using various methods for peak discharge assessment applying 6-hour storm rainfall duration. Rainfall-runoff models: HEC-1 option of the WMS software based on the American Soil Conservation Service (SCS) Curve Number (CN) Method and Mockus Method were used to compute runoff hydrograph peak discharge, and time to peak discharge in the Khazir river basin near the Mosul city North Iraq for dry, normal and wet soil cases. The aim of this study was to assess the ability of these two methods to predict design peak discharge in comparison with the observed data obtained. The results demonstrate that the peak discharges computed by HEC-1 in the WMS software method are mostly closest to the data observed. And the dry state of soil at CN=66 showed the best agreement with the observed data.

The combination of wavelet theory and neural networks has lead to the development of wavelet networks. Wavelet networks are feed-forward neural networks using wavelets as activation function. Wavelet networks have been used in classification and identification problems with some success. The strength of wavelet networks lies in their capabilities of catching essential features in ''frequency-rich" signals. In wavelet networks, both the position and the dilation of the wavelets are optimized besides the weights. Proposed multi wavelet network are used in identification problems of nonlinear systems. A multiwavelet network is constructed as an alternative to a neural network to approximate a nonlinear system.

Evolution in visual devices in all their forms has led to the development of a compatible in the areas of communications, image compression, broadcast satellite, terrestrial broadcasting.. etc., as well as color systems, which have grown consistently since the advent of the first simple color space in 1931 to this day with the advent of many modern systems with outstanding performance as a system of adaptive colors in 2002 and the system of higher quality now widespread. This research has been to focus on some of the color schemes with different patterns derived from the primary colors (RGB) and spaces of color inspired ones, which can be dealt with in mathematics and then represented in a technique to provide us with the possibility of conversion, transport, and core processors them, using mathematical formulas appropriate each system or chromatic space with the inclusion of equations necessary for the conversion processes between them and the electronic circuitry needed for their work. We selected different known test images from Baghdad, and the used the program MATLAB for analysis of some spaces of common use, such as color space(Y ', Cr, Cb) and space (Y', I, Q), the test results are compatible, as proved assess the changing colors outcomes in the application analyzes the foreground color, which applied to the image of the selected test.

This research deals with the subject of urban sprawl and its impact on agricultural land in the city of Baghdad, which is the subject of attention to him becoming a problem faced by the city of Baghdad by razing agricultural land and turning them into the role of residential or other construction, whether organized urban or be free of any organization of urban and surpassing the services despite the existence of laws to prevent overtaking on the planning Automat farmland within the design basis for the city. This has led to urban sprawl throughout the city of Baghdad and the expansion of its size dramatically over the past several decades. The research study the causes of urban sprawl on farmland and its effects and studies how to reduce it through the use of means Altaktith Urban process. And crystallized in the research problem: There is a lack of cognitive role in unplanned urban sprawl on agricultural uses of territory in the city of Baghdad. The research was based on the achievement of his goal of the hypothesis that: (whenever changed laws Urban are unplanned and non-compliance schemes foundation and the increasing population growth in a particular area the greater the expansion and urban sprawl are unplanned and thus reducing the acreage of arable land and green areas surrounding and beneficial to the environment of that area) .