Thermoelectric generator (TEG) has important applications in automotive exhaust waste heat recovery. The Back propagation neural network (BP) can predict the electrical generating performance of TEG efficiently and accurately due to its advantage of being good at handing nonlinear data. However, BP algorithm is easy to fall into local optimum, and its training data usually have deviation since the data are obtained through the simulation software. Both of the problems will reduce the prediction accuracy. In order to further improve the prediction accuracy of BP algorithm, we use the genetic algorithm (GA) to optimize BP neural network by selection, crossover, and mutation operation. Meanwhile, we create a TEG for the heat waste recovery of automotive exhaust and test 84 groups of experimental data set to train the GA−BP prediction model to avoid the deviation caused by the simulation software. The results show that the prediction accuracy of the GA−BP model is better than that of the B... [more]

The exhaustion of fossil energy and the severe pollution induced by using plastics has forced people to embark on the road to sustainable development. The high value of the recycling of plastics has become an important part of energy conservation. Microwave treatment, owning specific interactions between the electric field and the molecules of treated materials, presents potential advantages in the application of plastic pyrolysis. Therefore, the research status of the microwave-assisted pyrolysis (MAP) of plastics to produce high-value-added liquid oil, gas, and solid carbon was reviewed in this paper. The effects of plastic properties, microwave treatment parameters, microwave absorbers, co-pyrolysis, catalysts, and reactor devices on the process and the products were analyzed. It is essential to optimize the experimental design by studying microwave-assisted co-pyrolysis technology and the application of catalysts, understanding the mechanism of co-pyrolysis to improve product selec... [more]

This study examines the literature on improving the low performance of Savonius wind turbines, which are a type of vertical axis wind turbine. The literature studies on improving the performance of Savonius turbines have been summarized into two categories: interior structural design and exterior additional design. Due to the extensive nature of studies focusing on interior design changes, this research primarily focuses on performance studies related to exterior design modifications of Savonius wind turbines, particularly in recent years. This study aimed to provide a comprehensive examination of these performance studies and contribute to the existing literature by presenting a systematic reference on this issue. To achieve this objective, a thorough review of turbine exterior design studies has been conducted. The focus was on determining the percentage increase in power coefficient achieved by turbines with exterior design modifications compared to the classical turbine versions. H... [more]

The concept of geological engineering-integrated fracturing is widely applied in the conventional and unconventional reservoirs, aiming to achieve efficient and economic development. There is no doubt that fine reservoir evaluation is the basis and core of geological engineering-integrated fracturing. Therefore, in this paper, we performed a series of investigations on the basis of formation fine evaluation by using RoqScan technology. Firstly, the physical parameters of the target well located in Daniudi Gas Field were evaluated by a laboratory test and logging interpretation. Next, the composition and function of the RoqSCAN tool were introduce in detail. Furthermore, the elements, minerals, and rock mechanical parameters of the target well were evaluated by the RoqSCAN tool. Finally, the fine reservoir model was established on the basis of fine formation evaluation. Moreover, we conducted a series of research on porosity and principal stress of the target formation to compare the di... [more]

The use of Horizontal wells is a common method of underground natural gas storage (UGS), but there is still a need to discuss whether they are more suitable for slotted liner or perforation completions. To address this issue, a numerical model is developed to predict the gas injection rate of horizontal wells while considering the skin factor. Here, a novel uncoupled iteration method is employed to determine the skin factor deriving from turbulence in each time step when the bottom hole pressure is fixed. The uncoupled method begins with an estimate of the initial gas injection rate, which is then used to calculate a turbulent skin factor. This turbulent skin factor is then used to update the gas injection rate, iterating continuously until convergence is achieved. The effects of slotted liner and perforation design parameters, formation damage, and injection pressure on the skin factor are analyzed. The main findings suggest that the error in the gas injection rate calculated by the n... [more]

A fault is a common geological structure in coal mining. Large deformation or even instability and collapse often occur in roadways in fault areas, which restricts the safe and efficient production of mines. With the track roadway of the 5206 working face of Xin’an Coal Mine as the engineering background, this study aims to explore the failure mechanism of surrounding rock under the influence of fault structures. Field investigation and numerical simulation were used comprehensively to analyze the failure characteristics of the surrounding rock under the influence of a unidirectional fault structure. Based on the principle of thick-layer transboundary anchorage, the hierarchical continuous support technology of transboundary anchoring in the fault structure area was proposed. The results show that the stress near the fault area is relatively concentrated, and the rock mass strength is low, which may easily cause the deformation and failure of the surrounding rock under the dynamic stre... [more]

Petroleum-derived gasoline is still the most widely used liquid automotive fuel for ground vehicles equipped with spark-ignition engines. One of the most important properties of gasoline fuels is their antiknock performance, which is experimentally evaluated via the octane number (ON). It is widely accepted that the standard methods for ON measuring (RON: research octane number and MON: motor octane number) are very expensive due to the costs of the experimental facilities and are generally not suitable for field monitoring or online analysis. To overcome these intrinsic problems, it is convenient that the ON of gasoline fuels is estimated via faster methods than the experimental tests and allows for acceptable results with acceptable reproducibility. Various ON prediction methods have been proposed in the literature. These methods differ in the type of fuels for which they are developed, the input features, and the analytical method used to underlie the link between input features and... [more]

The integration of industrial batteries with photovoltaic applications is a common practice to charge the batteries using solar energy. Long-duration flow batteries are useful in dealing with the intermittency of renewable energy sources and offer a great opportunity for total fossil fuel replacement. In this study, the effects of different battery operation time and load profiles on the temperature dynamics of a containerised vanadium flow battery system are modelled and simulated for a range of locations and seasons to identify active cooling or heating requirements that might be needed to maintain safe operating temperatures. This paper explores and analyses the stack, tank, and container temperature dynamics of 6 h and 8 h containerised vanadium flow batteries (VFBs) during periods of higher charge and discharge current using computer simulations that apply insulation with passive or active hybrid cooling thermal management where needed to keep the battery temperature within a safe... [more]

One of the problems with the doubly-fed induction generator (DFIG) is its high vulnerability to network perturbations, notably voltage dips, because of its stator windings being coupled directly to the network. As the DFIG’s stator and rotor are electromagnetically mated, the stator current peak occurs during a voltage dip causing an inrush current to the critical converter back-to-back and an overload of the DC-link capacitor. For this purpose, a series of researchers have achieved a linear and non-linear controller with a crowbar-based protection scheme. With this type of protection, the Rotor Side Converter (RSC) is disconnected momentarily, and consequently, its control of both the active and reactive output power of the stator is totally lost, leading to incorrect power quality at the point of common coupling (PCC). In this document, a robust nonlinear controller by Advanced Backstepping with Integral Action Control (ABIAC) is initially employed to monitor the rotor and the networ... [more]

Research on the boiling vaporization process of liquid hydrogen spilled on solid ground is very important for the safety risk assessment of liquid hydrogen. Since the main source of the heat flux in the vaporization process comes from the ground, the heat flux from the ground into the liquid pool should be studied in-depth. In this paper, the boiling vaporization process of liquid hydrogen on the surface of concrete is studied. The analysis of the boiling process of a liquid pool is conducted by utilizing the boiling curve and historical temperature data collected in close proximity to the surface of the concrete. It was found that the boiling regime of a liquid hydrogen pool on the concrete surface presents non-uniformity, and the film boiling of liquid hydrogen on the concrete surface ended earlier than the results calculated by boiling regime correlations. When the measured temperature in the experiment indicates a transition from film boiling to the transition boiling, the temperat... [more]

Transportation of waxy crude oil in a production pipeline often encountered flow assurance issues, such as wax deposition. In a case where pipeline shutdown is needed, wax deposit is likely to form within the pipelines, which leads to operational complexity during the restart phase. Commonly, crude oil restarts to flow after a significantly high restart pressure is pumped longer than is necessary. This is due to the physical hindrance caused by the solid wax, which requires additional pressure to disintegrate it before achieving a steady crude oil flow. This study aims to investigate the effect of crude oil and nitrogen gas flow rates on the time taken for crude oil flow initiation using a flow loop rig, which is connected to a nitrogen gas injection system. The nitrogen gas was injected into the test section pipeline at predetermined flow rates within specified periods. After 45 min of static cooling, the crude oil gear pump is switched on to build sufficient pressure to initiate the... [more]

The continued use of energy sources based on fossil fuels has various repercussions for the environment. These repercussions are being minimized through the use of renewable energy supplies and new techniques to decarbonize the global energy matrix. For many years, hydrogen has been one of the most used gases in all kinds of industry, and now it is possible to produce it efficiently, on a large scale, and in a non-polluting way. This gas is mainly used in the chemical industry and in the oil refining industry, but the constant growth of its applications has generated the interest of all the countries of the world. Its use in transportation, petrochemical industries, heating equipment, etc., will result in a decrease in the production of greenhouse gases, which are harmful to the environment. This means hydrogen is widely used and needed by countries, creating great opportunities for hydrogen export business. This paper details concepts about the production of green hydrogen, its associ... [more]

The interaction mechanism between oil shale and catalyst is very important for the design and synthesis of related catalysis. In this work, dimethyl sulfoxide (DMSO) serves as a model molecule for organic sulfur compounds in oil shale to explore the catalytic effect and mechanism of the pure and transition metal Cu−doped SBA−15 molecular sieves regarding the decomposition of organic sulfur compounds in oil shale using the density functional theory (DFT) method. It is found that DMSO adsorption on both surfaces is primarily attributed to hydrogen bonding or the interaction between the S and O moieties within the molecule and the surface Cu atoms. The adsorption energies on both surfaces are indistinguishable; however, the Cu−doped SBA−15 shows enhanced catalytic activity in dissociation reactions. The Gibbs free energy changes for both possible reaction pathways of DMSO breaking C−S bonds on the pure SBA−15 surface are positive, and the activation energy barriers are as high as ~75 kcal... [more]

Several metaheuristic algorithms have been implemented to solve global optimization issues. Nevertheless, these approaches require more enhancement to strike a suitable harmony between exploration and exploitation. Consequently, this paper proposes improving the arithmetic optimization algorithm (AOA) to solve engineering optimization issues based on the cuckoo search algorithm called AOACS. The developed approach uses cuckoo search algorithm operators to improve the ability of the exploitation operations of AOA. AOACS enhances the convergence ratio of the presented technique to find the optimum solution. The performance of the AOACS is examined using 23 benchmark functions and CEC-2019 functions to show the ability of the proposed work to solve different numerical optimization problems. The proposed AOACS is evaluated using four engineering design problems: the welded beam, the three-bar truss, the stepped cantilever beam, and the speed reducer design. Finally, the results of the prop... [more]

Cement production is the third largest source of nitrogen oxides (NOx), an air pollutant that poses a serious threat to the natural environment and human health. Reducing NOx emissions from cement production has become an urgent issue. This paper aims to explore and investigate more efficient denitrification processes to be applied in NOx reduction from precalciner. In this study, firstly, the flow field, temperature field, and component fraction in the precalciner are studied and analyzed using numerical simulation methods. Based on this, the influence of the reductant injection height and amount on the SNCR was studied by simulating the selective non-catalytic reduction (SNCR) process in the precalciner. The effect of natural gas on the NOx emissions from the precalciner was also investigated. The simulation results showed that, with the increase in height, the NOx concentration in the precalciner decreased, then increased, then decreased, and then increased again. The final NOx conc... [more]

Thermal desorption technologies have been extensively applied for the disposal of oil-based drill cuttings. Fluent-software-based phase changes in multiphase flow models within thermal desorption chamber temperature field simulations were examined to study the effects of oil-based drill cuttings fluid content and feed rates, nitrogen content, thermal desorption chamber length and diameter, and extraction tube position on the thermal desorption chamber and temperature field. Our results demonstrate that these factors had a considerable influence on the temperature field of the chamber, with the liquid content of the oil-based drill cuttings having the greatest influence. The heat transfer process was enhanced by appropriately increasing the diameter and length of the chamber and reasonably setting the extraction tube. When the chamber length was insufficient, there was a risk that the outlet temperature would be extremely low and the oil content of the residue would exceed the standard.... [more]

This paper presents results obtained for the thermal and hydrothermal ageing of seven commercial precious metals-based catalysts for the combustion of methane. Experiments are performed in a large excess of oxygen representing lean conditions. Temperatures used are those typically found in lean burn compression ignition engines. The precious metals used were platinum, palladium and rhodium, present either singly or in combination. The most active catalyst contains a platinum and palladium mixture, with palladium being dominant. This catalyst was also the least affected by both thermal and hydrothermal ageing. The second most active catalyst contained only palladium, but this catalyst also demonstrated more susceptibility to ageing. The least active catalyst contained only platinum, although this catalyst was also the least affected by hydrothermal ageing. The addition of rhodium to either palladium or platinum−palladium catalysts caused a more rapid loss in activity at higher temperatu... [more]

Nineteen percent of global final energy consumption is used to generate electricity and heat in buildings. Therefore, it is undisputed that the building sector needs to cut consumption. However, this reduction needs to be driven by data analysis from real building operations. Starting from this concept and with the aim of proving the benefits deriving from the installation of a monitoring system in a real operating environment, in this work a monitoring system has been installed to monitor the centralised heating and cooling system of a residential building composed of 57 residential units. The data acquired from the installed sensors are collected and subsequently analysed in an ad hoc tool to detect anomalies, performance decay, malfunctions, and failures of the machines, as well as to understand if the implemented management strategy is appropriate in terms of energy and cost savings. The results show the key role of the data acquired by the monitoring system and analysed by the dev... [more]

Unmanned aerial vehicles (UAV)s have unique requirements that demand engines with high power-to-weight ratios, fuel efficiency, and reliability. As such, combustion engines used in UAVs are specialized to meet these requirements. There are several types of combustion engines used in UAVs, including reciprocating engines, turbine engines, and Wankel engines. Recent advancements in engine design, such as the use of ceramic materials and microscale combustion, have the potential to enhance engine performance and durability. This article explores the potential use of combustion-based engines, particularly microjet engines, as an alternative to electrically powered unmanned aerial vehicle (UAV) systems. It provides a review of recent developments in UAV engines and micro combustors, as well as studies on flame stabilization techniques aimed at enhancing engine performance. Heat recirculation methods have been proposed to minimize heat loss to the combustor walls. It has been demonstrated th... [more]

Land-based gas turbines (GTs) are continuous-flow engines that run with permanent flames once started and at stationary pressure, temperature, and flows at stabilized load. Combustors operate without any moving parts and their substantial air excess enables complete combustion. These features provide significant space for designing efficient and versatile combustion systems. In particular, as heavy-duty gas turbines have moderate compression ratios and ample stall margins, they can burn not only high- and medium-BTU fuels but also low-BTU ones. As a result, these machines have gained remarkable fuel flexibility. Dry Low Emissions combustors, which were initially confined to burning standard natural gas, have been gradually adapted to an increasing number of alternative gaseous fuels. The paper first delivers essential technical considerations that underlie this important fuel portfolio. It then reviews the spectrum of alternative GT fuels which currently extends from lean gases (coal b... [more]

The growing trend for electric vehicles (EVs) and fast-charging stations (FCSs) will cause the overloading of grids due to the high current injection from FCSs’ converters. The insensitive nature of the state of charge (SOC) of EV batteries during FCS operation often results in grid instability problems, such as voltage and frequency deviation at the point of common coupling (PCC). Therefore, many researchers have focused on two-stage converter control (TSCC) and single-stage converter (SSC) control for FCS stability enhancement, and suggested that SSC architectures are superior in performance, unlike the TSCC methods. However, only a few research works have focused on SSC techniques, despite the techniques’ ability to provide inertia and damping support through the virtual synchronous machine (VSM) strategy due to power decoupling and dynamic response problems. TSCC methods deploy current or voltage control for controlling EVs’ SOC battery charging through proportional-integral (PI),... [more]

In this article, a new non-isolated interleaved DC−DC converter is proposed to provide a high voltage conversion ratio in renewable energy systems. The converter configuration is composed of a two-phase interleaved boost converter integrating a voltage-lift capacitor and three-winding coupled inductor-based voltage multiplier modules to achieve high step-up voltage conversion and reduce voltage stresses on the semiconductors (switches and diodes). The converter can achieve a high voltage conversion ratio when working at a proper duty ratio. The voltage stresses on the switches are significantly lower than the output voltage, which enables engineers to adopt low-voltage-rating MOSFETs with low on-state resistance. The switches can turn on under zero-current switching (ZCS) conditions because of the leakage inductor series reducing switching losses. Some diodes can naturally turn off under ZCS conditions to alleviate the reverse−recovery issue and to reduce reverse−recovery losses. The i... [more]

This review investigates the effects of the Brazilian agriculture production and forestry sector on carbon dioxide (CO2) emissions. Residual biomasses produced mainly in the agro-industrial and forestry sector as well as fast-growing plants were studied. Possibilities to minimize source-related emissions by sequestering part of carbon in soil and by producing biomass as a substitute for fossil fuel were extensively investigated. The lack of consistency among literature reports on residual biomass makes it difficult to compare CO2 emission reductions between studies and sectors. Data on chemical composition, heating value, proximate and ultimate analysis of the biomasses were collected. Then, the carbon sequestration potential of the biomasses as well as their usability in renewable energy practices were studied. Over 779.6 million tons of agricultural residues were generated in Brazil between 2021 and 2022. This implies a 12.1 million PJ energy potential, while 4.95 million tons of for... [more]

Due to the high operating temperature of solid oxide fuel cells (SOFC), the system efficiency depends on efficient thermal integration and the effective construction of system configuration. In this study, nine configurations of system integration design were investigated to evaluate the possible improvement of system efficiency with energy separation devices. The models were developed under the Matlab/Simulink® platform with Thermolib® module. The reference layout of the simulation included an SOFC stack, a compressor, an external reformer with a burner, a three-way valve, a heat exchanger, and a water pump. From the reference case, eight cases extended layouts for the capability of thermal energy utilization with a catalytic converter, SOFC hybridization, and an energy separation device. Since the energy separation device was beneficial to thermal energy utilization via a boost to the gas temperature, electric efficiency, and combined heat and power (CHP) efficiency was improved with... [more]

Airborne dust and dust storms are natural disasters that transport dust over long distances from the source basin, sometimes reaching hundreds of kilometers. Today, Iraq is a basin that produces dust storms that strike all neighboring countries such as Iran, Kuwait and Saudi Arabia. These storms affect the productivity and capacity of the photovoltaic modules and reduce the amount of electricity that is generated clearly. Airborne dust reduces the intensity of solar radiation by scattering and absorbing it. In addition, the dust accumulated on the photovoltaic modules causes a deterioration in their productivity. In this study, an extensive review of wind movement and its sources, especially those that hit the city of Baghdad, the capital of Iraq, was conducted. Practical experiments were also carried out during a storm to measure important variables that had not been measured practically before at this site. The experimental tests were carried out starting from 1 April 2022 and contin... [more]