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Records Added in July 2023
Records added in July 2023
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Showing records 126 to 150 of 277. [First] Page: 2 3 4 5 6 7 8 9 10 Last
Column-Hemispherical Penetration Grouting Mechanism for Newtonian Fluid Considering the Tortuosity of Porous Media
Zhiquan Yang, Junfan Xiong, Xuguang Zhao, Xiangrui Meng, Shaobin Wang, Rui Li, Yuan Wang, Mao Chen, Na He, Yi Yang, Hanhua Xu
July 7, 2023 (v1)
Keywords: column-hemispherical diffusion, Newtonian fluid, penetration grouting mechanism, porous media, tortuosity effect
The intricate morphology of porous media can considerably affect the progression of penetration and the diffusion of grouting slurry. In this study, a Newtonian fluid’s refined seepage motion equation was proposed to incorporate the impact of tortuosity on the grouting process into gravel soil, and the column-hemispherical penetration grouting mechanism was analyzed using the method of theoretical analysis. Utilizing secondary-development programming techniques, a numerical simulation program was developed with COMSOL Multiphysics to model the penetration grouting mechanism of a Newtonian fluid in a column-hemispherical pattern, considering a medium’s tortuosity. The penetration grouting process of Newtonian cement into gravel soils was then simulated. Finally, the theoretical analysis, experimental values, and numerically simulated values were compared.The findings suggested that incorporating the tortuosity of porous media is more efficacious in depicting the penetration and diffusio... [more]
Energy Consumption Optimization Strategy of Hybrid Vehicle Based on NSGA-II Genetic Algorithm
Xuanxuan Wang, Wujun Ji, Yun Gao
July 7, 2023 (v1)
Subject: Other
Keywords: drive system, economy, hybrid vehicle, NSGA-II genetic algorithm, power
Hybrid electric vehicles (HEVs) have certain advantages over internal combustion engines in terms of energy consumption and emission performance. However, the transmission system parameters are uncertain. The low matching between the engine and the power transmission system makes it a big problem to improve the efficiency of hybrid vehicles. Therefore, the multi-objective optimization design of hybrid vehicles is studied. The transmission system parameters of hybrid vehicles are analyzed from the objective function, decision variables, and constraints. The NSGA-II algorithm with elite strategy is introduced to realize the optimal selection of parameters and formulation of energy consumption optimization strategy. The results showed that the multi-objective optimization algorithm could adjust the position of the working point of the engine and improve the efficiency by more than 10%. There was an average difference of 2.15% after the improvement in the fuel consumption of four-gear vehi... [more]
Using Direct Solar Energy Conversion in Distillation via Evacuated Solar Tube with and without Nanomaterials
Bahaa Saleh, Fadl A. Essa, Zakaria M. Omara, Mohamed H. Ahmed, Mahmoud S. El-Sebaey, Mogaji Taye Stephen, Lingala Syam Sundar, Mohammed A. Qasim, Eskilla Venkata Ramana, Sengottiyan Shanmugan, Ammar H. Elsheikh
July 7, 2023 (v1)
Subject: Materials
Keywords: condensation, direct immediate distillation, evacuated pipe, separation, solar collector
As is widely known, the issue of freshwater scarcity affects practically all people, and all are looking for innovative and workable ways to attempt to solve this issue. In this work, a novel method of desalination is proposed. The proposed system consists of a solar collector (PTSC), evacuated pipe (EP), condenser (CU), and separation unit (SU). The working principle of the system is heating the feed saline water using the PTSC and EP and controlling the water flow rate to control the output conditions of the EP. The produced vapor is therefore separated from salty water using the SU. In addition, the generated steam is condensed into the CU to produce a freshwater distillate. Consequently, the effect of solar radiation on the affecting temperatures was tested. In addition, the effect of using different water flow rates (6, 7.5, 10, 20, 40, and 60 L/h) inside the EP on the system productivity was investigated. The primary findings of this work may be highlighted in relation to the exp... [more]
Effect of Crude Oil Quality on Properties of Hydrocracked Vacuum Residue and Its Blends with Cutter Stocks to Produce Fuel Oil
Iliyan Kolev, Dicho Stratiev, Ivelina Shishkova, Krassimir Atanassov, Simeon Ribagin, Sotir Sotirov, Evdokia Sotirova, Danail D. Stratiev
July 7, 2023 (v1)
Keywords: blending, hydrocracking, intercriteria analysis, Petroleum, sedimentation, vacuum residue, viscosity modeling
The production of heavy fuel oil from hydrocracked vacuum residue requires dilution of the residue with cutter stocks to reduce viscosity. The hydrocracked residue obtained from different vacuum residue blends originating from diverse crude oils may have divergent properties and interact with the variant cutter stocks in a dissimilar way leading to changeable values of density, sediment content, and viscosity of the obtained fuel oil. H-Oil hydrocracked vacuum residues (VTBs) obtained from different crude blends (Urals, Siberian Light (LSCO), and Basrah Heavy) were diluted with the high aromatic fluid catalytic cracking (FCC) light cycle, heavy cycle, and slurry oil, and the low aromatic fluid catalytic cracking feed hydrotreater diesel cutter stocks and their densities, sediment content, and viscosity of the mixtures were investigated. Intercriteria analysis evaluation of the data generated in this study was performed. It was found that the densities of the blends H-Oil VTB/cutter sto... [more]
Simulation of Unsafe Behavior in Mine Operation Based on the SMAPP Model
Xidi Jiang, Shuheng Zhong, Jialu Liang
July 7, 2023 (v1)
Keywords: fuzzy rules, simulation framework, SMAPP model, unsafe behavior
Mine accidents are mostly caused by human unsafe behavior. To reduce the unsafe behavior of mine operation and reduce the accident of mine operation, the main body of unsafe behavior ‘people’ is analyzed, and 24 attribute factors are selected from five aspects of people’s emotions, motivation, ability, personality, and pressure to construct the comprehensive model of human behavior SMAPP (sentiment−motivation−ability−personality−pressure). The program tool for recording, saving, and executing the mutual and interactive influence relationship of 24 attribute factors under different state values and the simulation process framework of SMAPP was constructed by using 1071 rule statements written in Python language. The fuzzy rules are used to simulate different scenarios. The simulation results are consistent with the actual research results, which shows the reliability and scientificity of the model. In addition, additional events are added to the simulation process to make the model more... [more]
Crude Glycerol Hydrogenolysis to Bio-Propylene Glycol: Effect of Its Impurities on Activity, Selectivity and Stability
Martín N. Gatti, Francisco Pompeo, Nora N. Nichio, Gerardo F. Santori
July 7, 2023 (v1)
Keywords: 1,2-propylen glycol, biodiesel, crude glycerol, hydrogenolysis, nickel catalysts
The wide availability of crude glycerol and its low market price make this by-product of the biodiesel industry a promising raw material for obtaining high-value-added products through catalytic conversion processes. This work studied the effect of the composition of different industrial crude glycerol samples on the catalytic hydrogenolysis to 1,2-propylene glycol. A nickel catalyst supported on a silica−carbon composite was employed with this purpose. This catalyst proved to be active, selective to 1,2-propylene glycol and stable in the glycerol hydrogenolysis reaction in the liquid phase when analytical glycerol (99% purity) was employed. In order to determine the effect of crude glycerol composition on the activity, selectivity and stability of this catalyst, industrial crude glycerol samples were characterized by identifying and quantifying the impurities present in them (methanol, NaOH, NaCl and NaCOOH). Reaction tests were carried out with aqueous solutions of analytical glycero... [more]
Study on Multi-Objective Optimization of Logistics Distribution Paths in Smart Manufacturing Workshops Based on Time Tolerance and Low Carbon Emissions
Chao Wu, Yongmao Xiao, Xiaoyong Zhu, Gongwei Xiao
July 7, 2023 (v1)
Keywords: low carbon emission, path optimization, smart manufacturing, time tolerance, workshop logistics distribution
In the Industry 4.0 environment, an ideal smart factory should be intelligent, green, and humanized, and the logistics transportation from raw materials to final products in the factory should be completed by smart logistics. In order to address the problems of low efficiency, poor workstation service satisfaction, high distribution costs, and non-greening during the logistics distribution processes in discrete smart manufacturing workshops are required. A mathematical model of optimized multi-objective green logistics distribution paths in a smart manufacturing workshop has been constructed in this study, with low costs, high efficiency, and workstation service satisfaction taken into consideration. Then, this mathematical model was solved with an improved ant colony optimization algorithm. A “time window span” was introduced in the basic ant colony optimization algorithm to prioritize the services to workstations with a relatively high urgency in material demand, with the aim of impr... [more]
Natural Deep Eutectic Solvent Optimization to Obtain an Extract Rich in Polyphenols from Capsicum chinense Leaves Using an Ultrasonic Probe
Kevin Alejandro Avilés-Betanzos, Juan Valerio Cauich-Rodríguez, Marisela González-Ávila, Matteo Scampicchio, Ksenia Morozova, Manuel Octavio Ramírez-Sucre, Ingrid Mayanin Rodríguez-Buenfil
July 7, 2023 (v1)
Subject: Optimization
Keywords: Capsicum chinense, green extraction, natural deep eutectic solvent, Optimization, polyphenols, ultrasonic probe
Jacq., from the Yucatan peninsula, is recognized worldwide for its pungency, flavor, and secondary metabolites content. This has resulted in an increase in its production, which has led to an increase in the number of byproducts considered waste, mainly its leaves. Capsicum chinense leaves have been demonstrated to contain polyphenols with bioactive properties (antioxidant, anti-inflammatory, antiobesogenic capacity, etc.); hence, the extraction of polyphenols through the use of natural deep eutectic solvents (NADES) with a green technology, such as an ultrasonic probe, could help to revalue these leaves by maximizing the extraction efficiency and preserving their bioactive properties. The objective of this study was to optimize the composition of a eutectic solvent for obtaining an extract rich in polyphenols from the Capsicum chinense leaf using a sonic probe. The optimum conditions of the composition of NADES for obtaining the highest Antioxidant capacity (Ax, 79.71% inhibition) wer... [more]
Performance of a Nanofluid-Cooled Segmented Thermoelectric Generator: Hollow/Filled Leg Structures and Segmentation Effects
Cristian Francisco Ramos-Castañeda, Miguel Angel Olivares-Robles, Ana Elisabeth Olivares-Hernandez, Leobardo Hernandez-Gonzalez
July 7, 2023 (v1)
Keywords: Exergy, leg structure variation, nanofluids, numerical simulation, segmentation, thermoelectric generator (TEG)
A thermoelectric generator (TEG) is studied by considering different leg structures of hollow/filled legs, using new cooling nanofluids, and analyzing the segmentation effect. TEG performance is characterized by power output, conversion efficiency, and exergy efficiency. This study shows the impact of different cooling nanofluids (TiO2, graphene, and Al2O3) on the performance of the thermoelectric generator. Furthermore, in the comparative analysis of nanofluid cooling enhancement for TEG, different hollow/filled thermoelectric legs recently proposed in the literature are considered. Likewise, three segmentation types are used, 2n-2p, 1n-2p, and 2n-1p, thus will be compared with the results of the unsegmented legs. This study calculates the performance of thermoelectric leg structures through a validated numerical simulation on the ANSYS Workbench (modeling, design, and simulation). In addition, the optimal working conditions are evaluated. This study found that quenching of nanofluids... [more]
A Review on Impacting Parameters for Photocatalytic Degradation of Organic Effluents by Ferrites and Their Nanocomposites
Gurpinder Singh, Manpreet Kaur Ubhi, Kiran Jeet, Chetan Singla, Manpreet Kaur
July 7, 2023 (v1)
Subject: Materials
Keywords: ferrites, mechanism, nanocomposites, parameters, photocatalyst, photodegradation
Traditional wastewater treatment methods, such as reverse osmosis, adsorption, desalination, and others, are outweighed by the photocatalytic degradation of organic pollutants. Ferrites are prominent photocatalysts due to their tunable band gaps, surface areas, and magnetic properties, which render photodegradation economical. Ferrites and their nanocomposites have been reported as promising visible light active photocatalysts. The photocatalytic system is heavily reliant on a number of factors that influence the photodegradation of organic effluents. This review demonstrates various parameters such as substrate concentration, pH of solution, photocatalyst quantity, photocatalyst surface area, metal and non-metal ion doping, light intensity, irradiation time, quenchers, etc. affecting the photocatalytic degradation of organic effluents by ferrite nanoparticles and their nanocomposites in detail. The photodegradation efficiency of the ferrite nanoparticles alters with the change in the... [more]
The Use of Response Surface Methodology to Optimize Assisted Extraction of Bioactive Compounds from Cucurbita maxima Fruit By-Products
Rim Ben Mansour, Hanen Falleh, Majdi Hammami, Lillian Barros, Spyridon A. Petropoulos, Neji Tarchoun, Riadh Ksouri
July 7, 2023 (v1)
Keywords: antioxidant activity, by-products, Cucurbita maxima, response surface methodology, squash, total phenolic compound content
This work aimed to optimize the extraction conditions of bioactive compounds obtained from three squash by-products (e.g., peel, endocarp, and seeds) using the response surface methodology (RSM). The selected independent variables were ethanol concentration, extraction time, and extraction temperature. Squash by-products’ bioactive molecules were extracted according to the matrix proposed by the experimental plan. Significant variability in total phenolic compound content (TPC) and antioxidant activity, depending on the extraction time, the solvent concentration, and the extraction temperature, was recorded for the tested by-products. The experimental results adequately fitted with second-order polynomial models and showed significant linear, quadratic, and interaction effects of the independent variables. Data analysis suggested that the optimal extraction conditions were 12.2% ethanol for 11.2 min at 55 °C for peels; 28.5% ethanol for 10.5 min at 37 °C for endocarp; and 20% ethanol f... [more]
Optimal Allocation Method for Energy Storage Capacity Considering Dynamic Time-of-Use Electricity Prices and On-Site Consumption of New Energy
Wei Hu, Xinyan Zhang, Lijuan Zhu, Zhenen Li
July 7, 2023 (v1)
Keywords: Absorption, demand-side response, dynamic electricity price, Energy Storage, new energy, on site consumption of new energy
Configuring energy storage devices can effectively improve the on-site consumption rate of new energy such as wind power and photovoltaic, and alleviate the planning and construction pressure of external power grids on grid-connected operation of new energy. Therefore, a dual layer optimization configuration method for energy storage capacity with source load collaborative participation is proposed. The external model introduces a demand-side response strategy, determines the peak, flat, and valley periods of the time-of-use electricity price-based on the distribution characteristics of load and new energy output, and further aims to maximize the revenue of the wind and solar storage system. With the peak, flat, and valley electricity price as the decision variable, an outer optimization model is established. Based on the optimized electricity price, the user’s electricity consumption in each period is adjusted, and the results are transmitted to the inner optimization model. The inter... [more]
Production of Kojic Acid by Aspergillus niger M4 with Different Concentrations of Yeast Extract as a Nitrogen Source
Tomasa Quiterio-Gutiérrez, Susana González-Morales, José Antonio González-Fuentes, Adalberto Benavides-Mendoza, Fabián Fernández-Luqueño, Julia Medrano-Macías, Armando Robledo-Olivo
July 7, 2023 (v1)
Keywords: Aspergillus niger, kinetic modeling, kojic acid, liquid fermentation
In agro-industrial processes, microorganisms that are not pathogenic and that generate molecules are generally recognized as safe (GRAS). The Aspergillus niger fungus has different industrial applications, being used to produce citric acid and 166 other secondary metabolites. The objective of this research was to optimize a culture medium to induce the production of kojic acid (KA) by the Aspergillus niger M4 strain in a liquid fermentation process. Four fermentative kinetics were developed in flasks, using different levels of yeast extract in (1) 0.05 g/L, (2) 0.10 g/L, (3) 2.5 g/L, and (4) 2.5 g/L + Zinc sulfate. The culture medium conditions influenced the formation and speed of biomass and the synthesis and yield of KA. The optimum production points were from 72 h and 96 h with 0.552 g/L and 0.510 g/L of KA using 2.5 g/L of yeast extract and with a pH of 5.5. The Aspergillus niger M4 strain had the ability to produce kojic acid, which was induced by the concentration of the nitroge... [more]
Changes in Surface Hydrophobicity of Coal Particles and the Formation of Coarse Particle−Bubble Clusters in the Process of High-Intensity Conditioning
Xiaofu Jia, Yuexian Yu, Jiahui Liu, Chen Min, Fan Liu, Ningning Zhang, Songjiang Chen, Zhanglei Zhu
July 7, 2023 (v1)
Keywords: coal flotation, high-intensity conditioning, particle surface hydrophobicity, particle–bubble cluster
The mechanism of high-intensity conditioning (HIC) has not been thoroughly revealed, and therefore this work investigates the effect of HIC on the surface hydrophobicity of coal with different particle sizes and the possible formation of particle−bubble clusters. The results show that different HIC conditions are required for coarse and fine particles. Coarse particles (+75 μm) require a higher turbulence intensity to increase collector dispersion, thereby increasing the adsorption of the collector. Fine particles (−75 μm) require a lower turbulence intensity to reduce the desorption of the collector. In this study, the optimum HIC conditions for coarse and fine particles are “2200 rpm + 1 min” and “1300 rpm + 1 min”, respectively. Interestingly, it seems that the adsorption capacity between fine particles and the collector is weaker than that for coarse particles. A non-enclosed HIC system produces up to 1.78 × 104/g bubbles in coarse particle−bubble clusters, and the mean bubble diam... [more]
STITCH, Physicochemical, ADMET, and In Silico Analysis of Selected Mikania Constituents as Anti-Inflammatory Agents
Narayanaswamy Radhakrishnan, Vasantha-Srinivasan Prabhakaran, Mohammad Ahmad Wadaan, Almohannad Baabbad, Ramachandran Vinayagam, Sang Gu Kang
July 7, 2023 (v1)
Subject: Biosystems
Keywords: ADMET, cyclooxygenase, docking, human neutrophil elastase, lipoxygenase, methyl-3,5-di-O-caffeoyl quinate, Mikania, STITCH
The Mikania genus has been known to possess numerous pharmacological activities. In the present study, we aimed to evaluate the interaction of 26 selected constituents of Mikania species with (i) cyclooxygenase 2 (COX 2), (ii) human neutrophil elastase (HNE), (iii) lipoxygenase (LOX), matrix metalloproteinase ((iv) MMP 2 and (v) MMP 9), and (vi) microsomal prostaglandin E synthase 2 (mPGES 2) inhibitors using an in silico approach. The 26 selected constituents of Mikania species, namely mikamicranolide, kaurenoic acid, stigmasterol, grandifloric acid, kaurenol, spathulenol, caryophyllene oxide, syringaldehyde, dihydrocoumarin, o-coumaric acid, taraxerol, melilotoside, patuletin, methyl-3,5-di-O-caffeoyl quinate, 3,3′,5-trihydroxy-4′,6,7-trimethoxyflavone, psoralen, curcumene, herniarin, 2,6-dimethoxy quinone, bicyclogermacrene, α-bisabolol, γ-elemene, provincialin, dehydrocostus lactone, mikanin-3-O-sulfate, and nepetin, were assessed based on the docking action with COX 2, HNE, LOX, M... [more]
Monitoring and Analysis of the Driving Forces of Changes in the Ecological Environment of a Mining Area of Western China from 1986 to 2022
Lu Bai, Yingming Yang, Kai Zhang, Shuyu Liu, Gang Liu
July 7, 2023 (v1)
Subject: Environment
Keywords: coal mining area, ecological environment change, remote sensing ecological index
The remote sensing ecological index (RSEI) has been widely used in the rapid monitoring and evaluation of the regional ecological environment; however, the research on the main factors that cause changes in RSEI and the impact of human activities in the mining area on RSEI is not often explored. To this end, this paper selected the Landsat (TM/OLI) series of remote sensing images from 1986 to 2022; extracted the four important indicators of the normalized difference vegetation index (NDVI), the wetness component of the tasseled cap transformation (WET), normalized difference built-up and soil index (NDBSI), and land surface temperature (LST); calculated the remote sensing ecological index (RSEI) based on the principal component analysis method; monitored and evaluated the ecological environment changes in the Shendong Mining Area for a period of 36 years; and analyzed the driving forces that cause these ecological environment changes. The results show the following: (1) The ecological... [more]
Fast Deflagration-to-Detonation Transition in Helical Tubes
Igor O. Shamshin, Viktor S. Aksenov, Maxim V. Kazachenko, Pavel A. Gusev, Sergey M. Frolov
July 7, 2023 (v1)
Keywords: blended hydrogenous fuels, detonability, Ethylene, fast deflagration-to-detonation transition, Hydrogen, methane, propane, pulsed detonation tube, run-up distance
When designing a new type of power plants operating on pulsed detonations of gaseous or liquid fuels, the concept of fast deflagration-to-detonation transition (FDDT) is used. According to the concept, a flame arising from a weak ignition source must accelerate so fast as to form an intense shock wave at a minimum distance from the ignition source so that the intensity of the shock wave is sufficient for fast shock-to-detonation transition by some additional arrangements. Hence, the FDDT concept implies the use of special means for flame acceleration and shock wave amplification. In this work, we study the FDDT using a pulsed detonation tube comprising a Shchelkin spiral and a helical tube section with ten coils as the means for flame acceleration and shock amplification (focusing), respectively. To attain the FDDT at the shortest distances for fuels of significantly different detonability, the diameter of the pulsed detonation tube is taken close to the limiting diameter of detonation... [more]
Machine Learning Algorithms and Fundamentals as Emerging Safety Tools in Preservation of Fruits and Vegetables: A Review
Vinay Kumar Pandey, Shivangi Srivastava, Kshirod Kumar Dash, Rahul Singh, Shaikh Ayaz Mukarram, Béla Kovács, Endre Harsányi
July 7, 2023 (v1)
Keywords: Artificial Intelligence, fruit preservation, Machine Learning, nanotechnology
Machine learning assists with food process optimization techniques by developing a model to predict the optimal solution for given input data. Machine learning includes unsupervised and supervised learning, data pre-processing, feature engineering, model selection, assessment, and optimization methods. Various problems with food processing optimization could be resolved using these techniques. Machine learning is increasingly being used in the food industry to improve production efficiency, reduce waste, and create personalized customer experiences. Machine learning may be used to improve ingredient utilization and save costs, automate operations such as packing and labeling, and even forecast consumer preferences to develop personalized products. Machine learning is also being used to identify food safety hazards before they reach the consumer, such as contaminants or spoiled food. The usage of machine learning in the food sector is predicted to rise in the near future as more busines... [more]
Formulation of Nucleic Acids by Encapsulation in Lipid Nanoparticles for Continuous Production of mRNA
Alina Hengelbrock, Axel Schmidt, Jochen Strube
July 7, 2023 (v1)
Keywords: autonomous operation, continuous biomanufacturing, digital twins, in vitro transcription, lipid nanoparticles, Machine Learning, mRNA vaccine manufacturing
The development and optimization of lipid nanoparticle (LNP) formulations through hydrodynamic mixing is critical for ensuring the efficient and cost-effective supply of vaccines. Continuous LNP formation through microfluidic mixing can overcome manufacturing bottlenecks and enable the production of nucleic acid vaccines and therapeutics. Predictive process models developed within a QbD Biopharma 4.0 approach can ensure the quality and consistency of the manufacturing process. This study highlights the importance of continuous LNP formation through microfluidic mixing in ensuring high-quality, in-specification production. Both empty and nucleic acid-loaded LNPs are characterized, followed by a TFF/buffer exchange to obtain process parameters for the envisioned continuous SPTFF. It is shown that LNP generation by pipetting leads to a less preferable product when compared to continuous mixing due to the heterogeneity and large particle size of the resulting LNPs (86−104 nm). Particle siz... [more]
Digital Twin Implementation for Manufacturing of Adjuvants
Poonam Phalak, Emanuele Tomba, Philippe Jehoulet, André Kapitan-Gnimdu, Pablo Martin Soladana, Loredana Vagaggini, Maxime Brochier, Ben Stevens, Thomas Peel, Laurent Strodiot, Sandrine Dessoy
July 7, 2023 (v1)
Keywords: adjuvant particles, digital twins, Machine Learning, process analytical technology, process modeling, quality by design
Pharmaceutical manufacturing processes are moving towards automation and real-time process monitoring with the help of process analytical technologies (PATs) and predictive process models representing the real system. In this paper, we present a digital twin developed for an adjuvant manufacturing process involving a microfluidic formation of lipid particles. The twin uses a hybrid model for estimating the current state of the process and predicting system behavior in real time. The twin is used to control the adjuvant particle size, a critical quality attribute, by varying process parameters such as the temperature and inlet flow rates. We describe steps in the design and implementation of the twin, starting from the conception of the mechanistic model, up to the generation of its surrogate model used as state estimator, PATs and the setup of the information technology—Operational technology architecture. We demonstrate the performance of the twin by introducing different disturbances... [more]
Mechanical Properties of Full-Grouted Prestressed Anchor Bolts under Typical Bed-Separation Conditions
Zhen Zhu, Fulu Shang, Yubin Gao, Zelin Lu, Peng Zhang, Mingqing Du, Xiaoming Guan, Xuchun Wang
July 7, 2023 (v1)
Subject: Materials
Keywords: bed separation, full-grouted anchor bolts, mechanical property, prestressing force
For tunnel-support engineering, the bed separation of surrounding rock has a great influence on the support performance of bolts. In order to reveal the mechanical properties of the full-grouted prestressed bolt under the influence of bed separation, three typical working conditions of single-separation, multi-separation and different separation positions were set up, and theoretical models and numerical models were established. Furthermore, the characteristics of bolt axial force and anchorage−interface shear stress were analyzed by numerical method, and the sensitivity based on an orthogonal test was studied by means of range analysis and variance analysis. The results showed that: (1) under the single-separation condition, the separation value has a significant effect on the mechanical properties of the bolt, and with the increase in the separation value, the sliding failure unit of the bolt increases; (2) for multi-separation conditions, if the total separation value is the same, t... [more]
Production of Value-Added Products as Food Ingredients via Microbial Fermentation
Attia Iram, Ali Ozcan, Irfan Turhan, Ali Demirci
July 7, 2023 (v1)
Keywords: enzymes, food ingredients, microbial fermentation, value-added products, vitamins
Humankind has been unknowingly utilizing food fermentations since the first creation of bread, cheese, and other basic foods. Since the beginning of the last century, microbial fermentation has been extensively utilized for production of commodity chemicals. It has also gained substantial interest in recent decades due to its underlying applications in the preparation of natural and safe food ingredients including enzymes, antimicrobial agents, vitamins, organic acids, sweeteners, stabilizers, emulsifiers, oligosaccharides, amino acids, and thickening agents. In addition, some novel food ingredients that were conventionally made from some other sources such as plant tissue cultures or animals are now being introduced in the industry as ‘fermentation products.’ Some examples of such novel fermentation food ingredients include flavonoids, cultured meat products, food colorants, antioxidants, lipids, and fatty acids. This review summarizes some of the most prominent food ingredients and n... [more]
Thermoelectric Generator Design and Characterization for Industrial Pipe Waste Heat Recovery
Di Xiao, Peng Sun, Jianlin Wu, Yin Zhang, Jiehua Wu, Guoqiang Liu, Haoyang Hu, Jun Hu, Xiaojian Tan, Shi He, Jun Jiang
July 7, 2023 (v1)
Keywords: engineering application, generating performance, industrial pipeline wall, thermoelectric generator, waste heat recovery
Thermoelectric technology is an effective strategy to convert low−grade waste heat to electrical energy directly. Thermoelectric generators (TEGs) have been extensively studied in various waste heat scenarios, such as vehicle exhaust, metal casting processes and more. However, industrial pipelines also possess high levels of heat and wide distribution, yet there is limited research on TEGs for use in these pipes. The challenge in designing a TEG lies in the heat collector, which is complicated by the distinct structural differences between pipe and plate−shaped TEMs. Ultimately, we propose an arch bridge−shaped heat collector for the pipe to recover wasted thermal energy. The effects of some key factors, such as topology of TEMs, heat source temperature, cooling water temperature and velocity, on the generating performance are studied. The TEG achieved a temperature difference of 65.98 °C across the two ends of the TEM, resulting in an output power of 17.89 W at an open−circuit voltage... [more]
Numerical Simulation of the Effect of Heat Conductivity on Proton Exchange Membrane Fuel Cell Performance in Different Axis Directions
Longsheng Zhao, Kang Shang, Jiyao Wang, Zhenqian Chen
July 7, 2023 (v1)
Keywords: heat conductivity, heat transfer, mass transfer, porous electrodes, proton exchange membrane fuel cell
In this paper, the effect of changes in the thermal conductivity of porous electrodes in three coordinate directions on the capability of proton exchange membrane fuel cells is investigated on the basis of current density versus voltammetry curves, and the temperature distribution and water-carrying capacity distribution of the membrane. The results show that when the cell discharge voltage of the PEMFC is 0.3 V, the thermal conductivity in the Z-direction of the porous electrode has a greater effect on the performance of the PEMFC than in the other directions, with the thermal conductivity in the X- and Y-directions of the porous electrode having less than a 5% effect on the performance of the PEMFC, which can therefore be neglected. When the thermal conductivity of the porous electrode in the Z-direction of the PEMFC is 500 W/(m·K) and 1000 W/(m·K), the performance of the PEMFC is improved by 5.78% and 5.87%, respectively, and when the thermal conductivity of the porous electrode in... [more]
Active Disturbance Rejection Control of Five-Phase Motor Based on Parameter Setting of Genetic Algorithm
Rongtao Zeng, Jinghong Zhao, Yiyong Xiong, Xiangyu Luo
July 7, 2023 (v1)
Keywords: active disturbance rejection controller, five-phase induction motor, genetic algorithms, parameter setting
Five-phase induction motors have the characteristics of high torque density, low torque ripple, and flexible control, making them suitable for medium- and low-voltage power supply situations. However, with the expansion of application scenarios, five-phase motors need to cope with increasingly complex operating conditions. Five-phase motors for propeller propulsion will face various complex sea conditions during actual use, and five-phase motors for electric vehicles will also face various complex road conditions and operating requirements during use. Therefore, as a propulsion motor, its speed control system must have strong robustness and anti-disturbance performance. The use of traditional PI algorithms has problems, such as poor adaptability and inability to adapt to various complex working conditions, but the use of an active disturbance rejection controller (ADRC) can effectively solve these problems. However, due to the significant coupling between the variables of induction mot... [more]
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