International Journal of Engineering
Volume:37 Issue: 10, Oct 2024

Since the population and economic activities have increased energy demands, researchers and scientists have turned to recover wasted energy in various systems. This study aims to maximize energy recovery from marine diesel engines through heat exchange in four different types of wasted streams (exhaust gas, engine coolant, and engine oil coolant). In this research, four cycles of carbon dioxide critical recovery have been designed and modeled to utilize wasted heat energy from marine diesel engines (MAN B&W L35MC6-TII). The EES engineering software has been used for mathematical calculations. In each cycle, the effect of various parameters such as compressor outlet pressure, compressor inlet temperature, and turbine inlet temperature on output power, exergy efficiency, and compressor power consumption has been investigated. The results of this study indicate that the use of a heat recovery cycle in a diesel engine prevents the loss of a significant amount of energy in the engine. Additionally, increasing the fluid temperature at the compressor inlet reduces the output power and exergy efficiency in all recovery cycles. Increasing the fluid temperature at the turbine inlet reduces the compressor power consumption, increases the output power, and enhances the exergy efficiency in all recovery cycles. When the engine body coolant is used in the recovery cycle, the output power and energy system efficiency increase. Moreover, the cycle includes a generator to recover the heat output of carbon dioxide from the turbine. According to the findings of this study, despite the highest turbine output power (611.5 kW) belonging to the exhaust gas recovery system with two heat exchangers, the recovery system with a single heat exchanger has the highest usable output power (228.3 kW). This system had the highest energy and exergy efficiency of 17.72% and 12.85%, respectively.

The presents study numerically investigates the fiber-reinforced polymer (FRP) retrofitted short-damaged reinforced concrete (RC) columns subjected to axial compression load. The main parameter considered to evaluate the effectiveness of FRP retrofitting on circular columns with different aspect ratios, concrete grade, and FRP material. To simulate the behaviour of a short RC column under a uniaxial compression load, a finite element model of the column was developed. The model was then modified to simulate the various level of damage to the column and the behaviour of the column under uniaxial load. The effectiveness of FRP retrofit was studied comparing the behaviour of the retrofitted column to the damaged column. For M20 concrete column retrofitted with carbon fiber reinforced polymer (CFRP) showed a higher strength (2 to 3 times) than glass fiber reinforced polymer (GFRP) retrofitted columns. For M30 concrete, the range is quite similar (1.5 – 2.3 times more). The effectiveness of both FRPs retrofitted columns increases with increasing aspect ratio from 2 and 3, but slightly decreases for an aspect ratio of 4 compared to the damaged specimen. The maximum effectiveness achieved for CFRP retrofitted columns is of 19.45% and for GFRP retrofitted column is of 10.71%, and the other grade of concrete (M30) followed a similar trend. The load-bearing capacity of columns has no significant effect by the increase in aspect ratio from 2 to 4.

In addressing the critical challenge of developing sustainable energy solutions for electric vehicle (EV) battery charging, this study introduces an innovative direct current (DC) microgrid system optimized for areas with high solar irradiance, such as Ain El Ibel, Djelfa. The research confronts two primary difficulties: maximizing solar energy utilization in the microgrid system and ensuring system stability and response accuracy for reliable EV charging. To tackle these challenges, the study presents two original achievements. Firstly, it develops a neural network-enhanced Maximum Power Point Tracking (MPPT) controller, which is further optimized with Particle Swarm Optimization (PSO) to increase the efficiency of solar energy capture. Secondly, it refines the system's reliability through the advanced calibration of a Fractional Order Proportional-Integral (FOPI) controller using the Grey Wolf Optimization (GWO) technique, marking a notable improvement in microgrid system stability and response accuracy. The integration of a solar panel array, battery storage, and a supercapacitor, coupled with these advanced optimization techniques, exemplifies a significant leap forward in enhancing efficiency and reliability of EV battery charging through renewable energy sources. Comprehensive simulation and evaluation of the system underscore its superiority over conventional methods, demonstrating the effectiveness of combining neural network-based optimization with PSO and GWO. This breakthrough not only advances the field of renewable energy, particularly for solar-powered EV charging stations, but also aligns with global efforts towards sustainable transportation solutions.

In this paper the application of centrifugal type gas separator as a part of submersible electric screw pumping unit is considered. A number of bench tests have been carried out to study the centrifugal gas separator on viscous gas-liquid mixture. Calculation of the dependence of delivery on the developed pressure of a single screw pump at the angular speed of rotation of the rotor 225 rpm for different gas content has been made. Also, characteristic curves of gas separators of groups 5 and 5A at different gas contents and different viscosity of gas-liquid mixture are obtained. A methodology for bench testing of gas separators has been developed, which takes into account the influence of gas-liquid mixture properties, changes in the angular speed of the electric motor shaft rotation, and natural separation parameters. The operating parameters of a gas separator of group 5A were determined experimentally, taking into account a residual gas content of 50%, in the range of angular speeds of 252 – 1000 rpm (4.2 – 16.7 Hz).

This article presents a study on influence of Copper Concentration Electrolyte (CCE) and voltage on deposition rate of electroformed Conductive Acrylonitrile Butadiene Styrene (CABS) produced through Fused Deposition Modeling. Additive manufacturing is widely recognized as a rapid production technology. In this research, copper electroforming was selected as subsequent treatment following additive manufacturing. The novelty lies in implementation of pre-treatment process involving electroforming. The pre-treatment process employs carbon conductive paint to render the ABS part conductive. The copper electroforming process involves the use of variable parameters such as electrolyte content of (100, 150, and 200 gram CuSO4 and 50 ml H2SO4) in 1 liter H2O, voltage (1, 2, and 3 Volts), and time (2, 4, 6 and 8 hours). The variables under observation include the copper deposition rate and the microstructure. The analysis of research based on Kruskal-Wallis test. The difference in electrolyte copper concentration and the coating time does not provide significant differences, while the duration of electroforming affects the thickness of the copper deposit. Furthermore, the concentration of copper electrolyte influences the solution’s conductivity, at high concentrations leading to improve conductivity and consequently facilitating a fast deposition rate. The difference in voltage has a significant effect on the deposition rate and microstructure.

Aerosol particle charging is widely used in various technical applications. A model of a needle-plate type charger for efficient charging of aerosol nanoparticles in a corona plasma discharge has been developed and investigated. The main difference from similar devices in the modernization of the grounded plate hole's geometry and the number of corona needles exist. This has resulted in a substantial increase in the charger's efficiency by over 25%. The effects of two types of discharge plates, one with cylindrical and the other with conical inner holes, on the extrinsic charging efficiency of aerosol particles were experimentally investigated. Metallic nanoparticles of Ag with sizes ranging from 20 to 160 nm and a number concentration of 106 to 108 cm-3 were utilized as the test aerosol. This system shows that the maximum efficiency of particle charging is attained by using a plate with a conical hole, which reduces electrostatic losses from 37±3% to 20±2%. Furthermore, an additional effect of increasing the particle charging efficiency was also observed by using a multi-pointed needle, which resulted in lower electrostatic losses compared to a single needle. Experimental evidence confirms that utilizing a conical hole in the plate and a multi-pointed needle has increased the particle charging efficiency from 47±3% to 59±4%, as opposed to the standard design featuring a cylindrical hole and a single-pointed needle.  In this paper, an increase in the efficiency of charging particles in a charger with a multi-pointed needle compared to a single-pointed one is shown for the first time.

Nowadays, using social media has expanded in societies and organizations. So the question arises: What are the effects of social media on organizations? It seems the varied effects of social media on organizations altogether form a complex, dynamic system. This study examines this issue with system dynamics to model the dynamic complexity. The concept absorptive capacity is used as a mediator to apply the social media effects on the system. Absorptive capacity means the organization's ability to recognize valuable external information, assimilate, and utilize it in the organization, explaining the difference in the performance of organizations. After modeling, using the data obtained from a company active in the Iranian food industry, the relationships between the model variables are defined. To generalize the model, its variables are normalized so that the results can be applicable for different organizations. To improve the current situation, four policies are proposed and exerted to the model. The results demonstrate that proactively managing social media, compared to increasing the investment share of social media, has a more considerable effect on the organization's financial performance and market share.

For rubble mound breakwaters, incorporating a berm in the seaward slope can be very effective in reducing wave overtopping and mitigating wave loads acting on the breakwater armor elements. This research aims to investigate the effect of horizontal berm on the seismic response of conventional rubble mound breakwaters, considering various amplitudes and frequencies characterizing seismic loads. Finite element models of conventional rubble mound breakwaters, with and without berm, are developed using Plaxis 2D software for this purpose. Additionally, the stability of rubble mound breakwaters with berms is studied through various numerical models, considering different lengths and height levels of the berm. A comparative analysis of the results shows that rubble mound breakwaters incorporating berms exhibit lower deformation characteristics compared to those without berm. The numerical study results suggest that berms can significantly enhance the stability and reduce displacements of rubble mound breakwaters under seismic loading compared to breakwaters without berm.

The Covid-19 pandemic has caused changes in the field of business activities. The fear of the pandemic has increased consumer awareness of the economic benefits of e-commerce platforms and the desire of people to absentee shopping, resulting in the growth of e-commerce in the world. Iran is not an exception to this rule. In this article, in order to analyze the behavior of e-commerce consumers, before and during covid-19, Iran's largest online retail site has been studied. In the analysis of consumers' behavior, parameters such as spatial distribution, gender and age range of consumers, product groups, payment method for orders according to the amount of use of information and communication technology in the country before and during covid-19 and the death rate due to corona, were considered. In this research, data mining method has been used to analyze the behavior of e-commerce consumers. In the procedure, first the required data is collected and then in the next step, the data has been refined with the KNIME Analytics platform, and then consumer behavior has been analyzed using k-means and Fuzzy c-means algorithms. The results of the analysis showed that the spread of covid-19 has made the amount of shopping at the country level more uniform, leading older people to shop online and increasing their share of the total e-commerce consumers and the desire to pay for orders online. Also, the examination of product groups showed that the sales growth of health product groups was higher than other groups.

This study presents an evaluation of the conductivity of in-situ synthesis of LiFePO4/C-MAF-5 through the use of Response Surface Methodology (RSM) in optimizing process parameters.. Performance and optimization were established by combining RSM with the experimental carbonation process, crystallographic analysis using X-ray diffraction (XRD), and Fourier infrared spectroscopy (FT-IR). The results revealed that crystal structure is important in determining electrical properties, with conductivity consistently higher at smaller sample sizes. Furthermore, the main focus is provided on how the lattice parameters and electrical conductivity of LiFePO4 are affected by particle size. The higher electrical conductivity is due to the smaller particles, where reduced lattice strain is indicated. Furthermore, the success of the synthesis process was confirmed by the absorption peaks that corresponded to the expected LiFePO4 features and corresponded to specific vibrational methods as presented in the FT-IR spectrum results. The complex relationship between conductivity, LiFePO4 amount, and imidazole concentration is  demonstrated  by  the  RSM  contour  plot.  It  was  found  that  the  optimal  LFP  concentration  was 4 mol, the ideal Imidazole concentration was 58.79 mol, and the optimal temperature was set at 700 °C. Under  these  recommended  operating  conditions,  the  resulting  conductivity  was  determined  to  be 0.0000592 S cm-1.

Present study investigates the effects of managing a mobile energy storage system's (MESS) charging and discharging within a multi vector energy network (MVEN) to improve resilience, self-adequacy, load restoration capabilities, and cost-efficiency. It integrates renewable sources like photovoltaics and wind, with energy demands met via the grid, combined heat and power (CHP) systems, and renewables. The electrical and gas networks primarily meet electrical and heating demands, with gas fueling CHP and boiler units. The model also features gas and heat storage to balance demands and uses probability distributions function to account for uncertainties paramaters such as renewable outputs and loads. It tests the system's robustness against power disruptions from natural disasters, examining four case studies and three electric vehicle (EV) charging main scenarios, including a demand response program (DRP). The simulation results validate the effectiveness of the proposed approach in lowering energy costs and improving system resilience. The strategy of coordinated charging and discharging of EVs, combined with the use of DRP, results in significant cost savings and a more stable energy supply. Furthermore, the model's ability to scale and adapt to larger networks is highlighted, showcasing its potential for application in more complex energy systems.

Nowadays supply chain sustainability efforts are continuing to grow globally.  While the focus of typical supply chain management mostly is on the speed, cost and reliability of operations, sustainable supply chain management adds the goals of upholding environmental, financial and social responsibilities. Although the worth of supply chain management in large-scale projects, in particular, the construction industry has been recognized currently, its execution remains subject to significant challenges. One of the main challenges is the complexity of the sustainable suppliers’ selection. They can enhance the profitability and success of the project-oriented construction organizations. In this respect, this article aims to apply fuzzy Utilities-Additives STAR (UTASTAR), the extended Utilities Additives Method for multiple criteria decision, to select sustainable suppliers and evaluate general utility function of the problem. Finally, since this method belongs to compensatory multi-criteria decision-making models the results obtained through the application of the fuzzy UTASTAR were compared with some selected models from the compensatory subgroup. According to comparative results, fuzzy UTASTAR can identify deviation from actual utility of alternatives using upper and lower estimations. As a result, this study shows that the rankings produced by the fuzzy UTASTAR method are more trustworthy for selecting suppliers in ensuring the sustainable development.

There have recently been several initiatives to develop eco-sustainable materials because of the growing concern over ecological contamination caused by the overuse of synthetic materials. Previous studies in literature have explored the development of rice straw waste-based epoxy composites. Another waste hazard of concern in the current times is that of waste tire rubber. The present study investigates the physico-mechanical properties of a unique hybrid composite consisting of recycled waste tire rubber and rice straw reinforced composite, which has not been investigated in the literature. Their density, water absorption, hardness, tensile and flexural strengths were examined with variations in the proportion of rubber particles and rice husk. Increase in the rubber content resulted in proportional rise in the water uptake, hardness, tensile strength, and flexural strength. The composite with 25 wt.% of rubber and 5 wt.% of rubber showed the highest tensile strength and strain of 12.5 MPa and 0.015, respectively. The composite with 15% RS and WTR showed a 14.26% increase in flexural strength, with the neat composite exhibiting the highest strength. The composite material can be used as structural panels for instruments or devices in low load bearing applications. The developed sustainable material with waste generated from used tires and rice husk can aid in decreasing the harmful effects caused on the environment and human health during their disposal.

The design of a flying vehicle autopilot poses a significant challenge to the controller performance and the effectiveness of the flight control system. This challenge arises from uncertainties and extreme variations in parameters. To enhance the performance of the flight autopilot, the application of adaptive control techniques becomes crucial. Flight control systems extensively employ adaptive control methods due to their capacity to swiftly and automatically adapt to environmental changes and system dynamics, consequently achieving greater speed and accuracy. This paper aims to simulate scenarios where in the flight control system of an flying vehicle approach, with a specific focus on aerodynamic control in the roll, pitch, and yaw channels. The main purpose of the paper is to be able to provide an adaptive flight control system that can perform properly in the face of sharp and sudden changes in parameters. The paper compares the performance of the multiple model adaptive control method, particularly the switching and tuning technique, for the autopilot's roll, pitch, and yaw with other methods such as the reference model adaptive control used in previous research. The results demonstrate the superiority of the multiple adaptive controller utilizing switching and tuning techniques in handling parameter changes, exhibiting faster and more responsive behavior compared to traditional adaptive controllers.

The development of oil and gas infrastructure requires the development of new fields or the renewal of existing ones, which are mainly located in complex mining and geological conditions. Drilling intervals with abnormal formation pressures can cause a number of complications during cementing and subsequent well operation. The most common problem is inter-column pressures and cross-flow between formations. Gas migration may occur due to the fact that the mud has not been completely replaced by the cement slurry during cementing, and therefore there is no adhesion in the rock-cement contact zone. Understanding the process formation of cement slurry structural and rheological properties can reduce the risk of this problem and increase the casing anchoring efficiency. The study reveals that the rheological model of the same slurry can vary depending on various factors (temperature, water-cement ratio, cement slurry additives). Comparative results of laboratory studies on the effect of different concentrations of filtration loss reducer (FLR) from 0.1 to 0.5% and temperature in cement slurry are presented. As a result, the optimum concentration of FLR is selected, the range of which is from 0.2 to 0.3%. The analysis revealed that the accuracy of calculation of rheological parameters using the least squares method is higher than the industry standard. The deviation of numerical values of rheological model coefficients ranges from 7 to 60%. The approximation quality is assessed based on the sum calculation of the squared deviations.