Journal of Engineering

This paper presents the ability to use a cheap adsorbent (corn leaf) for the removal of Malachite Green (MG) dye from its aqueous solution. A batch mode was used to study several factors, including dye concentration (50-150 ppm), adsorbent dosage (0.5-2.5 g/L), contact time (1-4 days), pH (2-10), and temperature (30-60°C). The results indicated that the removal efficiency increases with the increase of adsorbent dosage and contact time, while inversely proportional to the increase in pH and temperature. An SEM device characterized the adsorbent corn leaves. The adsorption's resulting data were in agreement with the Freundlich isotherm according to the regression analysis, and the kinetics data followed pseudo-first-order kinetics with a correlation coefficient of 0.9309. The thermodynamic data show that the process is exothermic and reversible. The highest removal of MG was 91%, which gave proof that the corn leaves as adsorbent material have the capability of adsorbing the MG dye for aqueous solutions.

This paper presents the design and analysis of a narrow-band frequency amplifier operating in the 1.5GHz to 1.6GHz range using InGaP Heterojunction Bipolar Transistor (HBT) and GaAs HBT technologies. The design focuses on achieving high gain, low noise, and stability within the specified frequency range. The performance of the amplifier is evaluated through simulation and experimental results, demonstrating its suitability for applications requiring precise frequency amplification.

This paper investigates the characteristics of microstrip monopole antennas in free space and their performance when worn on the human body for wearable communications. Different patch shapes of microstrip monopole antennas are chosen to operate at two bands: industrial scientific and medical band (ISM) and ultra-wideband (UWB)1. The studied antenna consists of a radiating element on one side of the substrate and a partial ground plane on the other side. The antenna is supposed to be fabricated on cloth fabric with a relative dielectric constant of Ɛr = 1.7, and pure copper is used as the conducting part1. The software program of Computer Simulation Technology (CST) for Microwave Studio (MWS) is utilized to simulate the studied antennas. The results show that the proposed antennas of slotted hexagonal, rectangular, and circular shapes can operate from 2-12 GHz with bandwidths of 10.31 GHz, 10.19 GHz, and 9.67 GHz, respectively1. The hexagonal antenna is selected to investigate the effects of the human body on its performance. The human body is simulated, and its effects on the performance of the proposed antenna are studied1. The reflection coefficient, Voltage Standing Wave Ratio (VSWR), gain, and efficiency are found over that frequency range. The simulated results indicate that the human body effects are significant, and the proposed antenna showed to be a good candidate for wearable communications

his paper presents a numerical simulation of the flow around elliptic groynes using CFD software. The flow was simulated in a flume with dimensions of 4m long, 0.4m wide, and 0.175m high, with a constant bed slope. The first groyne was placed 1m from the flow inlet, with a constant height of 10cm and a thickness of 1cm. The width of the groynes was 7cm, and a submergence ratio of 75% was assumed, corresponding to a discharge of 0.0057m³/sec. The CFD model showed good accuracy in simulating the flow around groynes. The results indicated that using double elliptic groynes decreased bed shear stress with increased spacing between groynes. The best spacing between groynes was found to be twice the groyne width. Additionally, the number of groynes used had minimal impact on velocity and shear stress values.

This paper investigates the moisture and aging susceptibility of cold mix asphalt concrete. Laboratory experiments were conducted on two asphalt concrete mixtures used for the base course, prepared using conventional cold-mixing techniques. The mixtures included cutback and emulsion binders, different fillers, and curing times. The indirect tensile strength (ITS) of the samples was measured at 25°C. The results showed that the cold mix with the medium setting cationic emulsion (MSCE) binder had a higher ITS value compared to the cold mix with the cutback asphalt binder (MC-250). The MSCE mix demonstrated better moisture resistance and higher resistance to aging compared to the MC-250 mix.

This study investigates the use of electrical conductivity (EC) as a predictor for multiple water quality parameters in the Tigris River. Samples from different locations within the river's boundaries in Baghdad city were analyzed for drinking purposes. Correlation coefficients among different parameters were determined, and linear regression equations were developed to predict the concentration of water quality constituents such as total hardness (TH), calcium (Ca), chloride (Cl), sulfate (SO4), and total dissolved solids (TDS). Five regression models were produced and validated using EC as a predictor, showing good/excellent prediction ability for the parameters mentioned. This study provides a useful method for predicting surface water quality parameters and can be applied to other locations.

This paper reviews the synergic effects of mineral admixtures in ternary blended cement and its impact on concrete properties such as fresh properties, strength, durability, and efficiency factors. The review highlights that using two different types of mineral admixtures in ternary blended cement can achieve significant improvements in concrete properties, depending on the types of mineral admixtures used, replacement percentages by weight of cement, and age of concrete. The main conclusion is that concrete with ternary blended cement exhibits superior properties compared to binary blended cement.

his study evaluates the impact of variation orders on the cost and time of construction projects in the Sulaimani Governorate. Two hundred twenty-eight projects from various construction sectors built between 2007-2012 were analyzed to calculate the contract cost and schedule overruns due to variation orders. Data analysis included descriptive statistics and one-way ANOVA to determine whether the overrun of project cost and schedule significantly varied depending on project type, size, duration, location, and awarded years. The findings indicated that cost overruns are very common due to variation orders, with 95.6% of the projects studied being impacted, and overrun in project cost being significant at 16%. Time overruns were even more common, with 98.7% of the projects studied being affected by an average of 46.3% of the initial duration observed. The study highlights the need for better management of variation orders to minimize their impact on project costs and schedules.

This paper investigates the effectiveness of using nanomaterials in the roof of buildings to achieve energy conservation and improve indoor environment quality. The research focuses on the high thermal loads that roofs are exposed to compared to other elements in a building envelope. The study aims to determine the efficiency of nanomaterials in improving thermal performance and achieving energy conservation in the indoor environment of buildings. The theoretical aspect of the research involves the application of nanomaterials in roof systems, while the experimental aspect includes the simulation of standard roofs with nanomaterials, cool roofs, and standard roof systems using the Ecotect program. The results show that nanomaterials significantly affect thermal performance and enhance indoor environment quality by reducing energy consumption in buildings, especially in hot-dry climates like Iraq.