Journal of Engineering and Sustainable Development (JEASD)

With the evolution of electronics today, a MOSFET transistor is useful in many applications such as computers due to several advantages. In this research, an NMOS transistor differential amplifier circuit with a passive load that uses a modified Wilson current mirror as a biasing circuit is analyzed, designed, and implemented. The width-to-length ratios of transistors are calculated by considering the voltage and current values at the output of the biasing circuit, and parameters such as conduction parameter, base width modulation parameter, and threshold voltage. A MATLAB version 8.1.0.604(R2010a) programming tool is employed for calculations and the simulations are carried out via Multisim 9 software tool. The output resistance obtained for the current mirror is 2.297 "MΩ". CMRR, output resistance, and power dissipation for differential amplifier circuit are 33.351 "dB", 61.274 "kΩ" and 6.66 "mW", respectively. The results show that the width-to-length ratio, differential gain, and common-mode rejection ratio are decreased with decreasing applied voltage at the output of the biasing circuit while approximately the same values were obtained for output resistance and common-mode gain. The results show a good agreement between the measured values from simulation and the calculated one from design.

Recently, the products of dyes and phenols that effluent into the water cause serious environmental complications where they cannot be controlled and sustained in the environment. In this study, a special type of bentonite clay was used to remove two types of reactive dyes (red, green) and 2,4-dichlorophenol from water by adsorption processes, under different operating conditions of pH values between (4-9) contact time (30-180) min, bentonite dose (0.2-1) g/200 ml, initial concentration (5-100) mg/L for reactive dyes, and (5-50) mg/L for 2.4-Dichlorophenol. The adsorption model has been applied to represent fit the experimental data of the adsorption process. The results showed that the Langmuir model was more suitable to represent the removal of reactive dyes (red, green) and the Freundlich model was more suitable to represent the removal of 2,4-dichlorophenol by bentonite clay.

Transportation is an essential element for the development of countries economically, socially, and culturally. The progress in countries is measured through the progress in transportation systems and urban road networks. Al-Fallah intersection which lies northeastern of Baghdad city considered one of the highly congested urban centers, suffers congestion, particularly during morning and evening peak hours. The objective of this study is to analyze the delay time, degree of saturation, level of service in Al-Fallah intersection in Baghdad city using Synchro.10 software, in addition, to evaluate and analyze the intersection for choosing the best suggestion. The technique of video recording has been used for collecting the traffic volume data for all approaches from 7a.m to 4 p.m. for three days: Monday, Tuesday, and Wednesday. The operation analysis of isolated signalized intersection provides valuable and important information about the performance of the transportation systems in the city.The through movements of Al-Fallah Street illustrate the movement from the center of Al-Sadir city to Al-Rusafa and in reverse, they represent the heaviest traffic volumes in the Al-Fallah intersection. The Results of the analysis specified that the Al-Fallah intersection works under a level of service F with an average control delay of (322.1) seconds per vehicle and degree of saturation (2.56) v/c during the peak hours

This research deals with the thermal and thermo-structural behavior of concrete-steel composite box-girder bridges under the amalgamation of environmental thermal loads: global solar radiation, ambient air temperature, and wind speed. To achieve this goal, the experimental composite box-girder bridge segment with a full-scale cross-section erected on a campus of Gaziantep University, Turkey; and the series of numerical thermal analyses are conducted. The hourly fluctuations of the numerical temperatures matched well with the experimental ones. This research also submits a theoretical extensive study of the effect of shear connector’s number and arrangement at the concrete-steel interface on the hourly vertical thermal movements with an emphasis on the degree of composite interaction. Under partial interaction, the hourly vertical thermal displacements findings are presented to more visualize the design life of such constructions, as well as, the economic aspects as regards climatic impacts.

Construction and Demolition ( C&D ) waste constitutes a major portion of total solid waste produced in the world. The main purpose of this research is to study the effect of the addition of waste Yellow Clay brick powder (CBP) on the behavior of cement mortar and concrete of Grade (C25) at both conditions; fresh and hardened on the mechanical properties of concrete through by using of different partial replacement of powdered brick with cement until 100 percent by weight (0%, 5%, 10%, 15%, 20%, 25%, 50%, and 100% ) to produce concrete and to reduce the impact on the environment by consuming the material generally considered as a waste product. The yellow clay brick was crushed and ground manually and also sieve through 75µm sieve size in order to be fineness as cement. Cubes of size 150mm x 150mm x 150mm, Cylinders of size 300mm x 150mm and prisms of size 100mm x 100mm x 500mm were cast and tested, different ratios of waste CBP have been used to study its effect on the workability (slump flow), compressive strength and splitting tensile strength for 7, 14 and 28 days; and the modulus of rupture for 28 days. The results compared with the reference specimens and study the relationship between the mechanical properties of concrete.

The numerical investigation has been performed in this work to evaluate the performance of a triangular finned tube heat exchanger. In numerical work, the effect of space (2.5, 3 and 3.5 mm) distance between every two finned shaped and the volumetric flow rate on the heat transfer coefficient are examined consisting of cold water loop, hot air loop and the test section which is a concentric parallel flow double pipe heat exchanger. Coldwater and hot air are used as working fluids in the tube side and shell side, respectively. water at Reynold's numbers ranging from (3019.892 to 8035.044 ) flows through the inner tube. The inlet cold water temperatures are (45, 35, 25 and15) oC respectively. Numerical simulation has been carried out on the present heat exchangers to analyze both flow field and heat transfer using ANSYS, FLUENT15 computational fluid dynamic (CFD) package model. The finned tubes provide higher Nusselt numbers than the smooth tube. In the less pitch (p=2.5mm) compared with other pitches.

Moisture damage is one of the most common reasons for the premature deterioration of Hot Mix Asphalt (HMA) pavements. Over the years, extensive research has been carried out by scientists and engineers on this subject; however, pavements still succumb to early failure from infiltrating moisture. A very popular method of minimizing the moisture susceptibility of asphalt pavements is the use of anti-stripping agents. These additives are chemical substances that alter the physicochemical properties of the asphalt by making it more hydrophobic. This study focuses on the effect of anti-stripping agents on the moisture susceptibility of asphalt concrete mixture. The anti-stripping agents used were(SBS, Silica fume,and SBS with Silica fume)with different percentages. The laboratory tests include indirect tensile strength test, Marshall and retained Marshall Stability test (RMS) and double punching shear strength test. The test results show that the asphalt mixtures modified by (Silica fume+ SBS) have the highest values in Marshall Stability, RMS and it increased the moisture and stripping resistance. However, using (3% Silica fume+3% SBS) has the best effect on Marshall Stability, TSR value and stripping resistance. While (4% Silica fume+3% SBS) has the best effect on RMS value. From the experimental results, it is observed that the addition of anti-stripping agents had a significant positive influence on the results of the test properties being evaluated in each test

The safety factor is the most important point to consider when using medical radiology, as the walls of X-ray rooms must be immune to the radiation at a safe level. The theinsulationsthat are currently used in large rooms in the radiation is a lead substance and because of this substance of toxic effects on the human was only touch or inhalation of its evaporation. So Our research is aimed at reducing the amount of lead used by increasing the susceptibility of the concrete wall to insulate the radiation by addition of two types of polymers Rheobuild 833 and Rheomac uw450 to the standard M15Mix IS-10262 concrete mixture for the construction of insulating walls using molds metals with dimensions (20,20,10) cm, and in quantities of ( 100, 200, 300) mg and evaluated to determine their susceptibility to radiation capture. The best isolating was found at the addition of 200 mg, with an improvement rate of 29% for the Rheobuild 833 polymer and23% for the Rheomac uw450 polymer.

This work includes the design, manufacture and improvement of a Waste Heat Recovery System (WHRS) for thermal energy storage unit by using the PCM technique. Paraffin wax produced by Al- Durra refinery (a major Iraqi oil company) has been used as a phase change material for this purpose. The heat transfer enhancement has been investigated experimentally and numerically by using perforated and smooth copper strips inserted within paraffin wax in the form of fins. These coppers fins were welded with copper pipes in which water is flow inside it during the discharge process. The effect of fins and perforated fins with three different sizes of diameters (2,3 and 4 mm), on the heat transfer of PCM during the melting process, has been investigated to select the optimum among them. The results obtained indicate that inserting copper strips mainly rises heat transfer by conduction inside PCM and decreases the time of melting by about, 16% due to the high thermal conductivity of these strips and the smooth fins are more useful than perforated fins for improving the thermal properties of paraffin wax and the rate of heat transfer. It is also found that the increase in the diameter of the perforations led to a decrease in the thermal performance of the fins.

This investigation provides an experimental study about the structural behavior of reinforced hollow core slabs (HCS)by using recycled lightweight material. Sixhollow core slab specimens were cast with dimensions 1200mm length, 450mm width and different thicknesses (200mm, 250mm and 325mm). The shear reinforcement was used for each thickness to resist the shear failure that occur in the thick hollow core slab. The Recycled materials were crushed clay brick and iron powder waste. The crushed clay brick was used as a coarse aggregate instead of gravel to get lightweight concrete. The hollow core slab specimens were tested with age 28-day. The test was done by applying two-line loads up to failure. The experimental results showed an increase in the shear strength up to 50% and a decrease in the maximum deflection up to 50% with increasing thickness specimen. Also, the experimental results showed an increase in the shear strength up to 50% and an increase in the maximum deflection up to 50% with using shear reinforcement compare with hollow core slab specimens without shear reinforcement. The experimental results of this investigation can avoid the shear failure and change the mode of failure from the shear to flexural failure

Seven simply supported steel beams were tested to explain the effect of strengthening by external prestressing strands. All of these beams have the same steel section, clear span length and the strengthening samples implemented by two external prestressing strands. The tested beams are divided into two categories according to existing of external prestressing strands, the first category consists of one steel beam as a reference, while, the second group deals with steel beams strengthened by external prestressing strands and consists of six steel beams divided according to the eccentricity location of prestressing strand with jacking stress (814.589 MPa). During the test, it was found that the load-deflection curves for tested beams strengthening with external prestressing strand are stiffer as compared with the reference beams and the percentage of stiffening increases with increasing the eccentricity locations, while, the maximum load-deflection increase to 0.173%, 26.086%, 33.043%, 48.521%, 13.739

This research offers the ability to use natural waste as a biosorbent such as eggshells and their efficiency on heavy metals adsorption, like cadmium. Maximum removal was observed at pH 6.0. The efficiency of eggshells for the removal of cadmium was 89.7% at a 5g adsorbent dose. Effect of temperature change has been calculated, and parameters of thermodynamic indicated that the sorption of cadmium is favored at high temperatures and endothermic. FTIR was recorded before and after adsorption to show the number and position of the functional groups available for cadmium binding onto the studied adsorbent. It was found that Freundlich isotherm fitted well to the data; the Pseudo-second order model explains the cadmium kinetics more effectively. The results appeared that cadmium is considerably adsorbed on eggshells and it could be an economic method for the removal of cadmium from aqueous solutions.

The main objective of this research was to study the flexure behavior of hybrid reinforced concrete beams combining reactive powder concrete (RPC) and lightweight concrete (LWC). The experimental work consists of casting and testing in flexure seven simply supported reinforced concrete beams. The dimensions of (7) beams were geometrically similar, having rectangular cross-sections, of dimensions (125×200×1600) mm. Lightweight concrete was used in the tension layer and reactive powder concrete was used in the compression layer for all hybrid concrete beams. The main variables were; type of concrete (LWC and RPC), thicknesses of RPC layer (hR =0, 50, 100 and 200) mm and longitudinal reinforcement ratios (ρ= 0.0033 and 0.0227). The type of LWC used in the experimental work was porecilenite aggregate. The results showed that the characteristic strength (first and ultimate loads) was increased when the thickness of RPC layer was increased. In addition to that, these parameters have decreased the values of deflection. All beams failed by flexure mode without any shear cracks which were achieved by yielding tensile steel in the tension zone. Also, for all hybrid beams, the slip was absent between the concrete layers. Finally, the reinforcement ratio (ρ) had a more effective factor of all parameters used to increase the stiffness value of the beams which increased the characteristic strength and reduced the deflection values.

In this study, the effect of a commercially available titanium dioxide (TiO2) as a coupling on wood-filled polyethylene (PE) was investigated. The study revealed that the viscosity of the PE decreased with the addition of TiO2. The coupling agents help to improve the dispersion quality of the PE. The increase in the temperature of the wood-filled PE resulted in a corresponding decrease in the viscosity decreases. The thermal conductivity was found to increase with an increase in the volume fraction of the TiO2. Finally, the electrical resistivity of the wood-filled PE decreased with increasing volume fraction of the TiO2.

The research examines the possibility of producing insulating castable Refractory from locally available raw materials consisting of thermal aggregates represented by alumina bricks, which produce in large quantities in factories as industrial residues, and lightweight raw porcelainite aggregates as a partial replacement for thermal aggregates to give a lightweight character to thermal concrete, the white cement was also used at 25% and the white kaolinite at 5% to bind the ingredients, the castable which obtained is insulation refractory castable conforming to the requirements of the American specification ASTM C401 by porcelainizing aggregate in percentages (10, 15%) as a partial replacement of the thermal Alumina bricks aggregate, the dry density of manufactured refractory castable is (1.21, 1.24) g/cm3 with linear shrinkage at 1150c ° (1.38, 1.22)%, respectively.