This paper is interested in studying a system consisting of a wind turbine operating at variable wind speeds, and a two-feed asynchronous machine (DFIG) connected to the grid by a stator and fed by a transducer at the side of the rotor. The conductors are separately controlled for active and reactive power flow between the stator (DFIG) and the grid. The proposed controllers generate reference voltages for the rotor to ensure that the active and reactive power reaches the required reference values, to ensure effective tracking of the optimum operating point and to obtain the maximum electrical power output. Dynamic analysis of the system is performed under variable wind speeds. This analysis is based on active and reactive energy control. The new work in this paper is to introduce theories of genetic algorithms into the control strategy used in the switching chain of wind turbines in order to improve performance and efficiency. Simulation results applied to genetic algorithms give grea... [more]

With the uncertainty concerning the future use of natural resources due to depletion and lack of access caused by the pandemic and recent political events that led to increased prices, nuclear energy may become an alternative efficient energy. NPPs raise serious concerns, including waste management, and any case of an NPP accident has the potential to disrupt the positive impact of energy production in terms of circular economies. Our research analyzed the impact of nuclear incidents as examples of disasters worldwide to decide whether any of the different forms of insurance coverage could be useful in future events. By using 2533 historical records of incidents from 1901 to June 2022, we set out to find the best predictor of damage causes and further observe whether the validation of current forms of insurance may be possible. The disaster subtype and declaration represent the best predictor of the total damage value (adjusted or not) for all types of disasters, including nuclear. The... [more]

To improve energy efficiency and to recover energy, various mathematical models, such as pinch analysis, entropy analysis, exergy analysis, and entransy analysis, have been established to analyze heat transfer networks. In this study, these methods were applied to analyze the energy-saving effect of the epichlorohydrin unit in a certain enterprise. The results showed that when the minimum heat transfer temperature difference (ΔTmin) was 10K, 15K, and 20K, the efficiencies of the second law of thermodynamics calculated by entropy analysis were 88.02%, 93.52%, and 99.49%, respectively. The analytical method calculated an efficiency of 61.01%, 59.28%, and 57.27%, respectively, with public works’ savings of 16.59%, 14.86%, and 12.02%. The pinch analysis method achieved public works’ savings of 22.80%, 21.50%, and 19.35%. The entransy analysis method calculated an entransy transfer efficiency of 42.81%, 42.13%, and 41.00%, respectively, with public works’ savings of 19.41%, 18.01%, and 15.7... [more]

Industry 4.0 houses diverse technologies including wireless communication and shared networks for internal and external operations. Due to the wireless nature and remote operability, the exposure to security threats is high. Cyber risk detection and mitigation are prominent for secure industrial operations and planned outcomes. In addition, the system faces the threat of intelligence attacks, security standards issues, privacy concerns and scalability problems. The cyber risk related research problems influence overall data transmission in industry wireless communication networks. For augmenting communication security through cyber risk detection, this article introduces an Explicit Risk Detection and Assessment Technique (ERDAT) for cyber threat mitigation in the industrial process. A fuzzy harmony search algorithm powers this technique for identifying the risk and preventing its impact. The harmony search algorithm mimics the adversary impact using production factors such as process... [more]

The discharge of groundwater and the load on the lining structure are both significantly impacted by the obstruction of the tunnel drainage system. In this study, the fluid−structure interaction model was established based on the finite difference software FLAC3D. Then, this research explored the effects of symmetric and asymmetric blockage in the circular drainpipe, the transverse drainpipe and at the pipe joint in the tunnel on the pore water pressure, displacement and stress of surrounding rock. Our research revealed the following points: (1) When a symmetrical or asymmetrical blockage occurred in a circular drainpipe, only the blocked part of the drainpipe would be affected, but the pore water pressure at the back side of the tunnel crown and side wall lining between two adjacent circular drainpipes would increase by 200%, stress increase would increase by 22% and displacement would increase by 41%. (2) When a symmetrical or asymmetrical blockage occurred in a transverse drainpipe,... [more]

This paper aimed to introduce multiple-rack strategies in miniload automated storage and retrieval systems (AS/RSs), which included first fit (FF) and best fit (BF) assignment methods based on a matrix real-coded genetic algorithm (MRCGA) in the storage and retrieval process. We validated the probability occurrence of item sizes as a contributory factor in multiple-rack strategies, and compared their capacities, utilization of units and space by equal probabilities or the 80/20 law. According to the analytical methods, BF showed a reduction of more than 11.2% than FF on travel distance, and Type B-FF, Type B-BF and Type C-BF were better able to meet high-density requirements. These strategies provide diversified storage and retrieval solutions for the manufacturing and express delivery industry.

Coal pillars from old mines undergo creep, a type of time−dependent deformation. Research on underground engineering stability of coal mines has increasingly focused on long−term strength as an important mechanical index of the creep characteristics of coal pillars. This study performed conventional triaxial compression and triaxial creep tests of anthracite under different confining pressures. The creep law of anthracite and the long−term strength of anthracite was studied according to the test results. The test results demonstrated the following: (1) The conventional elastic modulus and peak strain of anthracite increased exponentially with the confining pressure. (2) Under low stress levels, anthracite exhibited only instantaneous deformation and attenuation creep. In contrast, anthracite exhibited instantaneous deformation, attenuation creep, and steady creep under high stress levels; accelerated creep occurred until failure when the stress reached a particular value. (3) By fittin... [more]

The isolation of single homologs of polyethylene glycol by preparative reversed-phase chromatography is investigated. A thermodynamic model developed accurately previously describes the retention times of individual homologs as function of their size, temperature, and mobile phase composition under linear, diluted conditions. The model is extended to predict limiting retention times for linear gradient operation in preparative applications. Isocratic and gradient-based separations are studied under strongly overloaded conditions. Baseline separation of homologs up to 3000 g/mol is demonstrated. Quantitative production of pure single homologs up to molar weights of 1000 g/mol was performed using an automated setup.

Hydrolysis of 2-Chlorobenzal chloride is the primary production method of 2-chlobrobenzaldehyde in industry, but the reactor technologies and reaction processes of this method are traditional and underdeveloped, in which the dichotomous leaf hydrolysis agitator is commonly used, resulting in low efficiency during the hydrolysis process. In this article, ANSYS software was utilized to enhance the hydrolytic reactors used in industrial production by simulating and analyzing the dispersion characteristics of droplets in the reactor. The particle size distribution of dispersed phase droplets and the Sauter mean diameter (D32) were used to characterize the dispersion effect, and the dispersion characteristics of the dichotomous leaf agitator and the three-bladed back-curved impeller, three-bladed propeller impeller, open turbine impeller, and crescent impeller were compared and studied. The results showed that there was a log-linear relationship between the D32 of the dispersed phase and th... [more]

A mechanistic model on catalyst deactivation by coke formation in a continuous stirred tank reactor (CSTR) has been developed in the paper. Catalyst deactivation by coke formation was treated as a surface reaction. Four reaction mechanisms representing coke formation through different routes were proposed. The evolved system of ordinary differential equations (ODEs) was solved numerically using MATLAB. This approach was validated by applying it to the skeletal isomerization of 1-pentene over ferrierite. Simulation results were compared qualitatively to those obtained from the literature. Simulation results indicated that coke formation is an extremely rapid process with fast formation of coke components on the strongest acid sites leading to final coke. The coke deposition is slower at higher residence times resulting in more stable product formation and weaker deactivation. The results obtained from this work revealed that the developed model is indeed able to successfully demonstrate... [more]

(Rupr. Maxim.; AS) is a medicinal plant used in the clinical treatment of cerebrovascular diseases and central nervous system disorders, and it significantly improves blood lipid levels and endothelial cell function in patients with acute cerebral infarction. Isofraxidin, one of the active ingredients of AS, is the core of the plant’s medical effects, and its extraction depends on organic solvents. Deep eutectic solvents (DESs) are new green solvents synthesized by intermolecular hydrogen bonding between hydrogen bond donors (HBD) and hydrogen bond acceptors (HBA) which are non-toxic, have a high separation and extraction efficiency, and are environmentally friendly compared to traditional organic solvents. In this paper, DES was used for the extraction of isofraxidin from AS. The primary findings demonstrated that the DES had a viscosity higher than that of ethanol, and even adding a small amount of water (approximately 10%) would trigger solvent redistribution, leading to a considera... [more]

Solar photovoltaic (PV) irrigation is increasingly used in agriculture, driven by its low operation cost and virtually zero emissions, providing electricity access in rural areas. However, the high investment cost requires an optimal design. The objective of this work was to develop a user-friendly tool to optimally size a PV generator that satisfies crop irrigation needs under local constrictions. The ODSIS (Optimal Design of Solar Irrigation System) tool, was organized in three calculation modules, preceded by two complements, which determine the daily crop irrigation needs and power demand of the pumping system. Then, the first module sizes the PV plant, considering a multiplication factor, and provides the PV production potential throughout each day of the season. The second and third modules evaluate the total investment cost and equivalent greenhouse gas emissions avoided by comparison with traditional energy sources. This tool was applied to a case study in Senegal for which a m... [more]

Industrial processes often involve a long time delay, which adversely affects the stability of closed-loop control systems. The traditional Smith Predictor (SP) is a model-based controller used in processes with large time delays. The variation of system parameters and load disturbance situations are disadvantages of the traditional SP, and researchers have, therefore, proposed modified SP structures. In this paper, a design method based on the direct synthesis approach on a modified SP structure is discussed. In the design, an I-PD controller structure is used on the set-point tracking side of the SP, and a cascading PD lead−lag controller is used on the disturbance rejection side. In contrast with other studies in the literature, the use of simpler controllers enables the mathematical expressions that arise in the direct synthesis method to be significantly reduced. The proposed method is examined under the disturbance input effects for normal and parameter-changing conditions on sys... [more]

Measuring the void fraction of different multiphase flows in various fields such as gas, oil, chemical, and petrochemical industries is very important. Various methods exist for this purpose. Among these methods, the capacitive sensor has been widely used. The thing that affects the performance of capacitance sensors is fluid properties. For instance, density, pressure, and temperature can cause vast errors in the measurement of the void fraction. A routine calibration, which is very grueling, is one approach to tackling this issue. In the present investigation, an artificial neural network (ANN) was modeled to measure the gas percentage of a two-phase flow regardless of the liquid phase type and changes, without having to recalibrate. For this goal, a new combined capacitance-based sensor was designed. This combined sensor was simulated with COMSOL Multiphysics software. Five different liquids were simulated: oil, gasoil, gasoline, crude oil, and water. To estimate the gas percentage... [more]

Precision medicine—of which precision prescribing is a core component—is becoming a new frontier in today’s healthcare. Both artificial intelligence (AI) and machine learning (ML) have the potential to enhance our understanding of data and therefore our ability to accurately diagnose and treat patients. By leveraging these technologies and processes, we can uncover associations between a person’s genomic makeup and their health, identify biomarkers associated with diseases, fine-tune patient selection for clinical trials, reduce costs, and accelerate drug discovery and vaccine development. Although real-world data pose challenges in terms of collection, representation, and missing or inaccurate data sets, the integration of precision medicine into healthcare is critical. Clearly, precision medicine can benefit from health information innovations that empower decision-making at the patient level. is an example of an innovative framework and process [K Zhai et al. ECKM 2022, 20(3), pp. 1... [more]

A material balance equation (MBE) is usually employed to estimate well-controlled dynamic reserves, but a more accurate calculation of these reserves is crucial. For abnormally pressured reservoirs with aquifers, the abnormally pressure and aquifer are difficult to determine, which leads to inaccurate calculations of well-controlled dynamic reserves. In this work, the MBE was established. Then, the correction function and abnormally pressure effect were deduced to determine well-controlled dynamic reserves calculations for weak aquifers and strong aquifers, respectively. For a weak aquifer, a pressure correction was determined to exist at a pressure coefficient of 1.2, and then the correction function was established to calculate the dynamic reserves. For a strong aquifer, the MBE derived by Walsh was employed to calculate the dynamic reserves and water influx. The relationship between the abnormally pressure effect and the dimensionless formation pressure was proposed. Classical, abno... [more]

Vitamins are a unit of organic chemical substances that are essential for the adequate working of the human body. Water-soluble B vitamins are involved in the regulation of many metabolic and regulatory processes. Due to the inability to synthesize endogenously, they must be supplied to the body with edibles or in the form of supplementation as drugs or dietary supplements. Maintaining the correct level of vitamins is extremely important in the treatment of various diseases. In the presented work, the qualitative and quantitative procedure of the assay of vitamins B1, B2, B5, B6 and B12 in pharmaceutical products by chromatographic technique coupled with densitometric detection was developed, optimized and validated. During the optimization process, TLC Silica gel 60 F254 plates were chosen as a suitable stationary, and the mixture consisted of chloroform: ethanol: water: glacial acetic acid (2:8:2:0.5 v/v/v/v) as a mobile phase. Densitometric detection was conducted at a maximum absor... [more]

Most large commercial vessels are propelled by low-speed two-stroke diesel engines due to their fuel economy and reliability. With increasing international concern about emissions and the rise in oil prices, improvements in engine efficiency are urgently needed. In the present work, a zero-dimensional model for a low-speed two-stroke diesel engine is developed that considers the exhaust gas bypass and geometry structures for the gas exchange model. The model was applied to a low-speed two-stroke 7G80 ME-C9 marine diesel engine and validated with engine shop test data, which consisted of the main engine performance parameters and cylinder pressure diagrams at different loads. The simulation results were in good agreement with the experimental data. Thus, the model has the ability to predict engine performance with good accuracy. After model validation, the variations in compression ratio, fuel injection timing, exhaust gas bypass valve opening portion, exhaust valve opening timing, and... [more]

With regard to speed, comfort, and a dense network of destinations, the popularity of air transport is on the rise. For this reason, jet fuel is a commodity with rapidly growing consumption and interesting refinery margins. At the same time, however, it is becoming a focus of attention in terms of reducing negative environmental impacts. As a response to these trends, it will be necessary to coprocess alternative petroleum fractions with sustainable aviation components in oil refineries. Six alternative jet fuel samples of different origin were used to investigate their jet fuel-specific properties, that is, aromatics (from 0 to 59.7 vol%), smoke point (from 12.2 to >50 mm), freezing point (from −49 to 50 mm) and freezing point (<80 °C).

Slivers on the surface of rolled plates, which are serious defects for interstitial-free (IF) steel, occur mainly as a result of inclusions in continuous casting (CC) slabs. It is, therefore, important to study inclusions in CC slabs in terms of their migration towards the surface during hot rolling. To investigate inclusion migration during the hot rolling of ultralow carbon steel, a 3D numerical model was constructed using the finite element method. The positions of the inclusions in the surface layer of an IF steel slab (50 mm) were tracked during hot rolling using a node-tracking method. Furthermore, the study analyzed the effects of scarfing on inclusion migration during hot rolling and inclusion distribution in a hot-rolled plate. During the hot-rolling process, inclusions in the wide faces of the intermediate slab gradually migrated to the surface of the intermediate slab. Owing to a thickness reduction, accumulation areas of inclusions were finally generated at the edge of the... [more]

As a follow-up to previous studies, the effects of Thymus vulgaris essential oil on selected virulence factors (growth, sessile cell survival, swimming, swarming, and exopolysaccharide production) were evaluated in phytopathogenic Pseudomonas syringae strains isolated from soybean fields in Argentina; reference strains Pseudomonas savastanoi pv. glycinea B076 and Pseudomonas aeruginosa PAO1. P. syringae are responsible for bacterial blight, a disease that affects crops worldwide. Plant bacterioses are usually treated with antibiotics and copper compounds, which may contribute to the development of resistance in pathogens and damage the environment. For these reasons, eco-friendly alternatives are necessary. Although aromatic plants are a natural source of antimicrobial substances, the effects of these substances on phytopathogenic bacteria remain largely unexplored. Subinhibitory concentrations of the oil significantly reduced the slope and rate of bacterial growth. In addition, biofil... [more]

Hydrogen liquefaction is an essential section for efficient storage and transportation of hydrogen energy. Both the Claude cycle and Brayton refrigeration cycle are available for large-scale hydrogen liquefaction systems. Two large-scale hydrogen liquefiers with the liquefaction capacity of 120 t/d based on the Brayton refrigeration cycle and the Claude cycle, respectively, are analyzed and compared in this study. Sensitivity analysis is used to optimize the parameters of two liquefaction systems in HYSYS. According to the results, the exergy loss and specific energy consumption of the Claude liquefier are 18.98 MW and 5.62 kWh/kgLH, which are 6.6% and 4.4% less than those of the Brayton liquefier, respectively. Exergy analysis reveals the exergy loss of compression and expansion systems in the Claude liquefier is less than that of the Brayton liquefier, while the exergy loss of the throttle valve in the Claude liquefier is more notable. In addition, the molar flow rate of hydrogen use... [more]

This study proposed a novel continuous roll-forming process of elastomer molds, which can control the deformation of the mold using the rolling belt stack combination method. This study analyzed various rolling belt combinations, assembled the system based on simulation and experimental data according to the deformation requirement design, and obtained a controllable microstructure mold rolling belt with tensile deformation. Mold thickness and microstructure size are key microstructure mold deformation parameters. This study designed and assembled a controllable microstructure mold rolling belt-type imprint molding system and conducted a series of experiments. The impact and application of different experimental system operation procedures and fabrication methods of the auxetic structure rolling belt on replication molding were analyzed. The innovative controllable microstructure mold rolling belt-type imprint replication molding technique proposed in this study had a stable and contro... [more]

Vitamin D (VitD) is essential for health and preventing diseases. This study aimed to investigate the possible association between VitD status and health status in 306 Libyan male and female young adults (18−25 Y) and adults (26−65 Y). There were 89.54% of subjects that had VitD levels below normal (<30 ng/mL), of which 45.42% were VitD deficient (<10 ng/mL) and 44.12% were VitD insufficient (10−29.9 ng/mL). VitD deficiency was associated with higher fasting blood sugar (FBS), low-density lipoprotein (LDL), and triacylglycerol (TAG) levels. Young adults had lower VitD levels than adults, which was associated with some health conditions. VitD insufficiency was associated with higher body mass index (BMI) values in adults, especially females, with higher FBS levels in adult males and higher hemoglobin A1c (HbA1c) levels in adult females. VitD deficiency in young adults was associated with higher TAG levels (more likely in adults) and lower high-density lipoprotein (HDL) values. Fur... [more]

The solid heat carrier moving bed with internals is an advanced oil shale retorting technology. However, the retorting gas produced by pyrolysis is generally used as fuel gas. The content of CO, H2, and CH4 in the retorting gas is high, and direct combustion leads to resource waste and environmental pollution. In addition, heteroatomic sulfur and nitrogen, as well as unsaturated hydrocarbons, reduce the quality of shale oil. To solve these problems, this paper proposed a chemical looping enhanced oil shale-to-liquid fuels (CLeSTL) process. The chemical looping hydrogen production technology is applied to convert retorting gas to hydrogen, and the hydrogen produced is used for shale oil hydrogenation to improve the oil quality. In this paper, the new process is modeled and simulated; then technoeconomic analysis is carried out. Technical analysis shows that shale oil yield is increased from 65% to 95.7% and the yield of light fraction is increased from 20% to 64%−83%. Economic analysis... [more]