The gas explosion process in pipes is often accompanied by an intense wall heat effect. A considerable part of the explosion energy is dissipated, and the process of gas explosion and its propagationis affected. In order to study the influence of wall heat effect on gas explosion and its propagation, numerical models of gas explosion in pipes with different adiabatic degrees were established by ANSYS/LS-DYNA. The propagation process of gas explosion in pipes under the influence of the wall heat effect was numerically simulated and analyzed, and the thermal stress and temperature distribution of pipes with different adiabatic degrees were studied. The results show that with a decrease in pipe insulation, the wall heat effect increases, the heat loss of gas explosion increases, and the overpressurizationof the shock wave, the explosion intensity, and the thermal stress of the pipe wall are significantly reduced. The results indicate that the wall heat effect can weaken the gas explosion... [more]

This article considers the design and control of the 2-butene metathesis process. The process transforms a low-value feedstock derived from a fluid catalytic cracking unit into more valuable products. The economical optimization is applied to the preheat−reaction and separation sections, with the objective of minimizing the total annual cost. The dynamic response and control of the plant are evaluated for feed flow perturbations. Although the process control system acts as a first line of defense against potential hazards, other independent safety layers are discussed with safety limits specific to the critical equipment of the 2-butene metathesis unit. The results prove that the metathesis reaction of 2-butene over a mesoporous tungsten catalyst is economically attractive. For a 5.7 t/h feed rate consisting of 2-butene (70% molar) and n-butane (30% molar), a reaction−separation plant (without recycle) requires 6570 × 103 $ investment and has a profitability of 2300 × 103 $/year.

This work aimed to evaluate the chemical composition of essential oils from Catha edulis Forsk collected in the Day Forest of the Republic of Djibouti. Additionally, in vivo toxicity studies, biochemical profiling, and hematological tests were conducted to determine the biological activity of the investigated essential oils. Finally, in vitro tests were performed to investigate the antibacterial activity of the essential oils. The essential oils were obtained at yields of 0.75%. Chromatographic analysis identified 39 compounds, of which cathinone (81.4%) and cathine (10.55%) were determined as the two major components, representing 91.95% of the total composition. Catha edulis essential oil had a rat LD50 of 2500 mg/kg, indicating very low toxicity. Chronic exposure studies revealed that use of the essential oil in rats resulted in persistent stimulant action at dosages of 100 and 200 mg/kg, whereas the weight gain of control rats was faster than that of the essential oil-treated rats.... [more]

The Y oilfield reservoir is characterized by ultra-depleted reservoir and multiple pressure systems in each well section. If conventional PLUS/KCL drilling fluid is used in directional drilling, the following problems are found: the rheological stability of drilling fluid is not sufficient, resulting in increased viscosity and thickening after aging, and the single plugging material may cause loss-circulation when the drilling differential pressure is more than 26 MPa, resulting in poor reservoir protection effects. To solve the above problems, based on the conventional PLUS/KCL drilling fluid formula, a PLUS/KCL drilling fluid system suitable for directional drilling in multi-pressure systems was formed by optimizing the addition of a treating agent to improve the rheological stability of the drilling fluid, optimizing the plugging agent and compound combination to improve plugging ability, and optimizing the particle size distribution of a temporary plugging agent to improve the rese... [more]

A novel UV-light-active MCC/S-VO2 photocatalyst was successfully synthesized by a simple and reliable hydrothermal route. XRD, FT-IR, Raman analysis, XPS, FE-SEM, EDX, TEM, DRS, and thermal analysis techniques were utilized for the characterization of the as-prepared photocatalysts. The photocatalytic activities of the V2O5, doped S-VO2, and MCC/S-VO2 nanostructures were investigated by monitoring the fading out of the methylene blue (MB) concentration under UV-light irradiation. The results revealed that the photocatalytic degradation of MB via MCC/S-VO2 was superior compared with that exhibited by pure V2O5 and doped S-VO2. It was found that 72.3% of MB (100 mL; 20 mg·L−1) was degraded after 6 h in contact with MCC/S-VO2. Interestingly, the photodegradation of MB dye was enhanced dramatically by adding H2O2, while 92.5% of MB was degraded within 55 min. The kinetic studies revealed that the MB degradation followed the pseudo-first-order model with a rate constant (kobs) of 3.9 × 10−2... [more]

Thermal runaway occasionally happens in batteries. A single battery, after thermal runaway, will release heat and transfer it to neighboring batteries, leading to thermal runaway of battery packs. Thus, it is necessary to explore the diffusion law of thermal runaway in battery modules. Heating is by far the most common way to trigger thermal runaway propagation of battery modules. In this paper, experiments and simulations were conducted to explore the influence of different heat insulation thicknesses on the thermal propagation of lithium iron phosphate batteries, and the result shows that the best thickness between adjacent batteries is 2 mm. For complex modules, the simulation analysis shows that when the spacing between adjacent modules in the battery pack was 10 mm and thermal runaway occurred on one side of the battery pack, it did not occur on the other side for a certain period of time. Therefore, the recommended spacing between modules in the battery pack is 10 mm. This lays a... [more]

With the increasing proportion of close-distance coal seam mining in China, the problem of strong mining pressure during the mining of close-distance coal seams is becoming more and more severe. This article focuses on the complex stress environment and severe mining pressure encountered in the mining of thick coal seams under the multi-coal-seam goaf of Zhunnan Coal Mine. By using research methods, such as similar material simulation, theoretical analysis, and numerical simulation, it studies in depth the instability characteristics of the overlying rock structure of the W1701 working face, the inducing factors and mechanisms of strong mining pressure during the mining process, and control measures. The results show that the roof structure of the W1701 working face can be divided into “high-level key layer (hard rock)−giant thick soft and weak rock group−low-level key layer (hard rock)”, and the law of mining pressure manifestation presents a small cycle formed by the instability of “... [more]

The mobile phone industry, one of the fastest advancing sectors in production over the last few decades, has been associated with a high e-waste generation rate. Simultaneously, a high demand for the production of new electronic equipment has led to the scarcity of certain metals. In this context, many recent studies have focused on recovering certain metals from e-waste through the use of bioprocesses. Such recovery processes are based on the action of microorganisms that produce Fe(III) as an oxidant, in order to leach the copper contained in printed circuit boards. During the oxidation-reduction reaction between Fe(III) and metallic Cu, the color of the solution evolves from an initial reddish color, due to Fe(III), to a bluish-green color, due to the oxidized Cu. In this work, a hardware-software prototype is developed, through which the concentrations of the key analytes—Fe(III) and Cu(II)—can be determined in real time by monitoring the color of the solution. This is achieved thr... [more]

Unexpected instances have posed challenges to production lines over the last few years. The latest COVID-19 global epidemic is one notable example. In addition to its social impact, the virus has destroyed the traditional industrial production system. Industry 4.0 requires adapting to changing prerequisites with adaptability. However, the next movement, Industry 5.0, has emerged in recent years. Industry 5.0 takes a more coordinated approach than Industry 4.0, with increased collaboration among humans and machines. With a human-centered strategy, Industry 5.0 improves Industry 4.0 for greater sustainability and resilience. The concept of Industry 4.0 is the interconnection via cyber-physical systems. Industry 5.0, also associated with systems enabled by Industry 4.0, discusses the relationship between “man and machine,” called robots or cobots. This paper discusses the industry 5.0 possibilities, the restrictions, and future analysis potentials. Industry 5.0 is a new paradigm change th... [more]

The construction of new renewable energy infrastructures and the development of new ocean resources continues to proceed apace. In this regard, the increasing size and capacity of offshore wind turbines demands that the size of their accompanying supporting marine structures likewise increase. The types of marine structures utilized for these offshore applications include gravity base, monopile, jacket, and tripod structures. Of these four types, monopile structures are widely used, given that they are comparatively easy to construct and more economical than other structures. However, constant exposure to harsh cyclic environmental loads can cause material deterioration or the initiation of fatigue cracks, which can then lead to catastrophic failures. In this paper, a 3D fatigue finite element analysis was performed to predict both the fatigue life and the crack initiation of a welded monopile substructure. The whole analysis was undertaken in three steps. First, a 3D non-steady heat c... [more]

Joining similar or dissimilar materials has recently become a hot topic in industries. In this study, an adhesive technique was used to join plastic materials produced by additive manufacturing (3D printing) with metal materials. The effects of the type of material that forms the joint pairs on the joint strength were investigated. In addition, a case study was carried out on the “rubber-metal buffer” part, which is a rubber industry product. The “rubber-metal buffer” part, traditionally produced by vulcanization, was re-manufactured by changing the body material and production technique. Samples were produced from Tough PLA and TPU materials using a 3D printer at 80% and 100% fill rates. Adhesive joints were made by bonding dissimilar (Tough PLA/Galvanized steel, TPU/Galvanized steel, Tough PLA/TPU) and similar materials (Tough PLA/Tough PLA, TPU/TPU, Galvanized steel/Galvanized steel) using Loctite 9466 adhesive. The mechanical properties of the joints were determined using tensile a... [more]

Saudi Arabia initiated its much-anticipated Vision 2030 campaign, a long-term economic roadmap aimed at reducing the country’s reliance on oil. The vision, which is anticipated to be accomplished in the future, underlines compliance, fiscal, and strategy adjustments that will significantly affect all the important features of Saudi economic growth. Technology will be a critical facilitator, as well as controller, of the initiative’s significant transformation. Cloud computing, with the Internet of things (IoT), could make significant contributions to Saudi Vision 2030’s efficient governance strategy. There are multiple IoT applications that cover every part of everyday life, as well as enabling users to use a variety of IoT applications. Choosing the best IoT applications for specific customers is a difficult task. This paper concentrates on the Kingdom’s advancement towards a fresh, as well as enhanced, method of advancing the development phases pertaining to digital transformation, t... [more]

Gas−liquid transportation is an efficient and economical transportation technology developed in recent years. It mainly uses some transportation equipment to simultaneously transport crude oil, associated natural gas, produced water, and so on for the purpose of reducing costs and energy consumption. In this paper, a double-chamber gas−liquid transferring device was selected as the research object. The VOF multiphase flow model of FLUENT software was used to simulate the gas−liquid two-phase flow performance under the design condition. The relationships between the two-phase flows, pressure, temperature, liquid level in the tank, outlet flow rate of the device, and time were calculated and analyzed. The results show that the operating cycle of the device can be divided into three processes, namely ‘suction-compression-discharge’, in which the cycle period formula is proposed as well. The pressures of gas and liquid in the device are basically the same, but the temperatures of the two p... [more]

The Xihu sag has two main oil−gas fields: Huagang Gas Field and Pinghu Oil Field. The Huagang formation is the reservoir of the Huagang Gas Field in the Central Tectonic Zone, while the Pinghu formation is the reservoir of the Pinghu Oil Field in the Western Slope Zone. In this paper, which mainly focusses on the Huagang formation, we conducted gas-driven water displacement−magnetic resonance imaging (GWD-MRI) experiments to simulate the charging characteristics of the sandstone migration layer, centrifugal magnetic resonance (Cen-NMR) experiments to simulate the short-term rapid trap charging process, and semi-permeable baffle (SPB) charging experiments to simulate the slow trap accumulation process. The results indicate that a start-up pressure exists for migration layer charging, where the start-up pressure for a core with a permeability of 0.3 mD is about 0.6 MPa. Our experimental simulations confirm that a planar front of changing water saturation exists, which has a width of abou... [more]

This work focuses on introducing new sustainable chemicals in the wool grease removal processes by aiming to understand the effect of an eco-friendly solvent, cyclopentyl methyl ether (CPME), in solvent-based wool grease extraction and, in addition, the impact of the wool protein hydrolyzate (WPH) as a biosurfactant derived from green hydrolysis in the wool scouring process. In the green solvent extraction process assisted using solvent CPME, the effect of CPME on grease extraction and the presence of four primary fatty acids were evaluated and compared with conventional solvents. The quantity of grease extracted using green solvent CPME was more significant than the conventional solvents. An extraction using green solvent CPME resulted in 11.95% extracted wool grease, which is more when compared with 8.19% hexane and 10.28% diethyl ether. The total quantity of four fatty acids was analyzed and found to be ~15% for CPME ~17% for Hexan compared with ~20% for commercial lanolin. FTIR of... [more]

The Zeta converter is an essential and widely used high-order converter. The current modeling studies on Zeta converters are based on the model that devices, such as capacitors and inductors, are of integer order. For this reason, this paper takes the Zeta converter as the research object and conducts an in-depth study on its fractional-order modeling. However, the existing modeling and analysis methods have high computational complexity, the analytical solutions of system variables are tedious, and it is difficult to describe the ripple changes of state variables. This paper combines the principle of harmonic balance with the equivalent small parameter method (ESPM); the approximate analytic steady-state solution of the state variable can be obtained in only three iterative steps in the whole solving process. The DC components and ripples of the state variables obtained by the proposed method were compared with those obtained by the Oustaloup’s filter-based approximation method; the s... [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]

The moving average filter-based phase-locked loop (MAF-PLL) can obtain grid synchronization signals accurately under adverse grid conditions with a large amount of harmonics due to the high filtering capability of the MAF. However, MAF-PLL cannot achieve a fast dynamic response in the case of frequency drift, phase angle steps, and unbalanced voltage sag. MAF is essentially an FIR filter, and its filtering performance is hard to be adjusted. To address this issue, this paper proposes an alternative to MAF consisting of a set of cascading second-order IIR filters (CIIRF). Based on MAF, CIIRF introduces multiple zeros and poles from the zero−pole replacement perspective, and by changing the position of the poles, the filter performance can be adjusted. To improve the anti-interference ability of PLL based on CIIRF (CIIRF-PLL) in the presence of grid frequency drift, a frequency-adaptive scheme is also proposed. Simulation and experimental results show that CIIRF-PLL can accurately track... [more]

It is important to consider the thermal management of lithium-ion batteries to overcome their limitations in usage and improve their performance and life cycles. In this study, a novel cooling system for the thermal management of lithium-ion battery packs is proposed by using an inner cylinder in the cooling channel and different-shaped nanoparticles in the base fluid, which is used as the cooling medium. The performance improvements in a 20 Ah capacity battery are compared by using a water−boehmite alumina (AlOOH) nanofluid, considering cylinder-, brick-, and blade-shaped nanoparticles up to a solid volume fraction of 2%. The numerical analysis is conducted using the finite element method, and Reynolds numbers between 100 and 600 are considered. When the efficacy of the coolants utilized is compared, it is apparent that as the Reynolds number increases, both cooling media decrease the highest temperature and homogenize the temperatures in the battery. The utilization of the cylinder i... [more]

The tremendous and fast green transition in Denmark has initiated the large-scale grid-integration of renewable energy sources, electrification of energy consumption, and establishment of PtX and Energy Islands, setting goals for transmission grid development—such as the establishment of new connections—and for grid reconstruction—such as the extensive substitution of overhead lines (OHLs) with underground cables (UGCs). The share of UGCs in the Danish transmission grid is increasing. Presence of UGC has resulted in that resonances of the harmonic impedance characteristics of the transmission grid are brought within the harmonic order range coinciding with the harmonic emission sources and causing systemwide increase of the harmonic voltage distortion in the 400 kV transmission grid. The transformation of the 400 kV transmission grid has given rise to the need to predict harmonic voltage distortion using simulation models to secure an adequate power quality and support investment decis... [more]

Nowadays, stationary battery storage systems are generally used to optimize the self-consumption of electricity generated locally or to limit the peak load of the local grid connection. Self-consumption optimization aims to achieve economic benefits by using more of the self-generated electricity within the local grid. Batteries used for the optimization of self-consumption tend to present low states of charge and, therefore, normally do not contribute to peak load limitation. Peak load limitation is used to minimize the grid connection power to enable more cost-efficient grid connections. However, this function can only be achieved year-round if there is sufficient surplus electricity production or if the battery can be charged from the grid. In the latter case, the batteries are often fully charged and do not significantly optimize the self-consumption. This study presents a new operating strategy that combines all the advantages of the previous operating modes with none of the disad... [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]

After the Paris Agreement was signed in 2015, many countries worldwide focused on the hydrogen economy, aiming for eco-friendly and renewable energy by moving away from the existing carbon economy, which has been the primary source of global warming. Hydrogen is the most common element on Earth. As a light substance, hydrogen can diffuse quickly; however, it also has a small risk of explosion. Representative explosion accidents have included the Muskingum River Power Plant Vapor Cloud Explosion accident in 2007 and the Silver Eagle Refinery Vapor Cloud Explosion accident in 2009. In addition, there was an explosion in a hydrogen tank in Gangneung, Korea, in May 2019, and a hydrogen refueling station (HRS) in Norway exploded in 2018. Despite this risk, Korea is promoting the establishment of HRSs in major urban centers, including downtown areas and public buildings, by using the Regulatory Sandbox to install HRSs. This paper employed the Hydrogen Risk Assessment Model (HyRAM) of Sandia... [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]

Advanced metering infrastructure (AMI) is becoming increasingly popular as an efficient means of energy demand management. By collecting energy data through AMI, it is possible to provide users with information that can induce them to change their behavior. To ensure that AMI continues to expand and to encourage the use of energy data, it is important to increase consumer participation and analyze their preferred service attributes. This study utilized a choice experiment to analyze consumer preferences for and acceptance of smart energy services based on AMI data. The results of a mixed logit model estimation show that consumers prefer the electricity information service for individual households and the social safety-net service among convergence services. A scenario analysis confirms that monetary compensation to offset any additional charges is important to maintain the level of consumer acceptance. These empirical findings offer insights for policymakers and companies seeking to d... [more]