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Records added in 2023
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Showing records 576 to 600 of 36336. [First] Page: 20 21 22 23 24 25 26 27 28 Last
Phycoremediation of Synthetic Dyes Laden Textile Wastewater and Recovery of Bio-Based Pigments from Residual Biomass: An Approach towards Sustainable Wastewater Management
Vivek Kumar Nair, Koushalya Selvaraju, Saurabh Samuchiwal, Farah Naaz, Anushree Malik, Pooja Ghosh
July 7, 2023 (v1)
Subject: Environment
Keywords: algal-bacterial consortia, bio-based pigments, dye degradation, phycoremediation, textile wastewater
The textile industry is a growing sector worldwide and has immense opportunity in terms of providing employment and boosting a nation’s economy. However, there exist severe environmental risks associated with textile effluents that impact the surrounding ecosystem. This review offers an approach for sustainable water management using phycoremediation to treat dye-laden wastewater and recover bio-based pigments from the residual biomass. Microalgae such as Chlorella, Scenedesmus, Phormidium, and macroalgae like Sargassum, Enteromorpha, and Codium has been extensively used in several phycoremediation-based studies, and their residual biomass could be a potent source for extraction of bio-based pigments. This review also recommends studies involving the algal-bacterial consortia approach for treating dye-laden wastewater as an alternative to conventional, biobased methods. The outcome of this study will provide policymakers and researchers with new insight to manage water and wastewater r... [more]
Is Regulatory Approval without Autonomous Operation for Natural Extract Manufacturing under Economic Competitiveness and Climate-Neutrality Demands Still Permissible?
Alexander Uhl, Larissa Knierim, Martin Tegtmeier, Axel Schmidt, Jochen Strube
July 7, 2023 (v1)
Keywords: autonomous operation, digital twins, digitalization, green technology, natural extraction, natural remedies, regulatory approval
Natural extracts are broadly utilized as remedies, nutrition additives, cosmetics or flavors as well as natural pesticides, fungicides or herbicides. Green manufacturing technologies are of added market value and are sustainable towards the climate neutrality politically demanded for 2045. The concept of digital twins involves experimentally distinct validated process models combined with process analytical technology that is to be adapted to the existing operations. This is a key technology for the autonomous operations in industry 4.0. This paper exemplifies this approach and evaluates the results of the application and implementation efforts of regulated industries. A conductivity sensor for the measurement of the dry residue content and/or Fourier-transformed infrared spectroscopy for marker/lead or reference substance concentration determination are the most feasible and straight forward solutions. Different process control concepts from simple PID controllers (proportional, integ... [more]
Numerical Experiments on Performance Comparisons of Conical Type Direct-Acting Relief Valve—With or without Conical Angle in Valve Element and Valve Seat
Huiyong Liu, Qing Zhao
July 7, 2023 (v1)
Keywords: AMESIM, CTDARV, performance comparisons
This paper conducts numerical experiments on performance comparisons of CTDARV—with or without conical angle in the valve element and valve seat. The working principles of three kinds of CTDARV are introduced. The simulation models of three kinds of CTDARV are established by utilizing AMESIM. Numerical experiments on CTDARV, with or without a conical angle in the valve element and the valve seat, are conducted and the performance comparisons of three kinds of CTDARV are obtained. The results show that: (1) When all parameters of VED, VSD, VEM, SS, CAVE&CAVS, and OD have the same value, respectively, CA-VE has the highest stable pressure, CA-VE&VS has the highest stable displacement, CA-VS has the lowest stable pressure, and CA-VE has the lowest stable displacement. The stable pressure of CA-VE is significantly higher than that of CA-VS and CA-VE&VS. The stable displacement of CA-VE&VS is significantly higher than that of CA-VE and CA-VS, and the stable displacement of CA-VE and CA-VS h... [more]
A Damage Identification Method Based on Minimum Mean Square Error Estimation for Wind Tunnel Flexible Plate Condition Monitoring System
Kang Yun, Mingyao Liu, Jingliang Wang, Cong Li
July 7, 2023 (v1)
Keywords: damage identification, generalized likelihood ratio test, minimum mean square error estimation, wind tunnel flexible plate
In this paper, we propose a damage identification method based on minimum mean square error estimation for a wind tunnel flexible plate condition monitoring system. Critical structural members of important equipment are large in size, and the measurement systems used to monitor their condition are often complex. The proposed damage identification method is based on the minimum mean squared error estimator and the generalized likelihood ratio test. It introduced activation function to generate the standard deviation of the data, which can then simulate the sensor output. A single sensor damage only affects a single dimension of the output data matrix of the measurement system. However, structural damage affects the output of multiple sensors. The damage identification method proposed in this paper can not only distinguish the sensor damage from the structure damage, but also locate the damaged sensor or structure damage location. This method can identify the measurement system output an... [more]
Pd-M (M = Ni, Co) Bimetallic Catalysts with Tunable Composition for Highly Efficient Electrochemical Formic Acid Oxidation
Qingwei Ding, Qing Luo, Liang Lin, Tianlun Yang, Xingping Fu, Laisen Wang, Caixia Lei
July 7, 2023 (v1)
Keywords: bimetallic alloy, electrocatalysts, formic acid oxidation, fuel cell
Bimetallic Pd-based catalysts for formic acid oxidation (FAO) are one of the most promising anode materials for the next generation of direct formic acid fuel cells (DFAFC). It is imperative to develop a simple strategy for preparing efficient, stable, and clean nanoparticle catalysts. Herein, we prepared a series of Pd, PdNi, and PdCo nanoparticle catalysts using the nanoparticle beam composite deposition system, which revealed good catalytic activity and stability in the process of FAO. The incorporation of Ni or Co prevents the adsorption of active intermediates and the accumulation of toxic intermediates in the process of FAO. Therefore, more Pd active centers can be used to decompose formic acid directly by dehydrogenation. The results indicate that PdNi-2 (Pd0.9Ni0.1) and PdCo-3 (Pd0.89Co0.11) catalysts exhibit the optimal catalytic performance, with the mass activity of 1491.5 A g−1Pd and 1401.7 A g−1Pd, respectively, which is 2.1 and 2 times that of the pure Pd sample. By optim... [more]
Pulmonary Delivery for miRs: Present and Future Potential
Archana Shrestha, Md Anamul Haque, George Mattheolabakis
July 7, 2023 (v1)
Subject: Materials
Keywords: liposomes, micro-RNAs, naked miRs, nanocarriers, pulmonary delivery, RNA interference
Administration through the respiratory tract can be advantageous, with high drug bioavailability, limited enzymatic activity, reduced dose requirements compared to oral, and potentially diminished side effects. Among the different types of drugs studied for pulmonary delivery, genetic material delivery has gained favorable scientific interest, using polymer-, lipid-, inorganic-, or vector-based nanocarriers. As pulmonary drug delivery has been associated with challenges, including physiological barriers and lung metabolism, the delivery of sensitive molecules such as nucleic acids can exacerbate these challenges. While short-interfering RNAs (siRNAs) have been extensively reported as suitable ribonucleic acid interference (RNAi) candidates for pulmonary delivery, discussion on micro-RNA (miR) pulmonary delivery is limited despite their significant therapeutic potential. Recently, these non-coding RNAs have been explored in targeted or non-targeted pulmonary administration against vario... [more]
Enhancing Power Generation Stability in Oscillating-Water-Column Wave Energy Converters through Deep-Learning-Based Time Delay Compensation
Chan Roh
July 7, 2023 (v1)
Keywords: Artificial Intelligence, deep learning algorithm, maximum power point tracking, optimal control, oscillating-water-column wave energy converter, output power performance, rated power control, Renewable and Sustainable Energy, time delay
Oscillating-water-column wave energy converters (OWC-WECs) are gaining attention for their high energy potential and environmental friendliness. However, their irregular input energy characteristics pose challenges to achieving stable power generation, particularly due to high peak power compared to average power. This study focuses on stable rating control to enable continuous power generation in the presence of irregular wave energy. It is difficult to precisely configure the existing rated power controllers due to physical time delays; this impacts system stability and utilization. To address this, we propose a rated power controller that compensates for system time delays using a deep learning algorithm. By predicting the valve control angle in advance and analyzing the input data for angle estimation, we successfully compensate for the physical time delay. The performance of the proposed rated power controller, incorporating the deep learning algorithm, is evaluated by analyzing t... [more]
Development and Validation of High-Performance Liquid Chromatography for Identification and Quantification of Phytoecdysteroids Ecdysterone and Turkesterone in Dietary Supplements
Velislava Todorova, Kalin Ivanov, Diana Karcheva-Bahchevanska, Stanislava Ivanova
July 7, 2023 (v1)
Subject: Materials
Keywords: 20-hydroxyecdysterone, dietary supplements, high-performance liquid chromatography, phytoecdysteroids, Rhaponticum carthamoides Willd, turkesterone
Phytoecdysteroids are a group of naturally occurring ecdysteroid hormones found in certain plant families and used for centuries for their adaptogenic, tonifying, and antioxidant properties. Ecdysterone and turkesterone are the dominant phytoecdysteroids found in the plant species Rhaponticum carthamoides Willd., Cyanotis arachnoidea C.B.Clarke and Ajuga turkestanica (Regel) Briq., and have been recognized for their adaptogenic potential and ability to enhance physical performance. However, over the past few years, supplementation with ecdysterone by professional athletes has raised some concerns about its safety and quality, leading to its inclusion in the World Anti-Doping Agency monitoring program. This study proposes a simple and reliable method for quality control of ecdysterone- and turkesterone-containing products using high-performance liquid chromatography (HPLC) analysis. The HPLC method is based on reversed-phase chromatography and gradient elution to achieve a superior sepa... [more]
Synthetic Minority Oversampling Enhanced FEM for Tool Wear Condition Monitoring
Yuqing Zhou, Canyang Ye, Deqiang Huang, Bihui Peng, Bintao Sun, Huan Zhang
July 7, 2023 (v1)
Keywords: finite-element modeling, sample missing and insufficiency, synthetic minority oversampling technique, tool wear condition
Recent advances in artificial intelligence (AI) technology have led to increasing interest in the development of AI-based tool wear condition monitoring methods, heavily relying on large training samples. However, the high cost of tool wear experiment and the uncertainty of tool wear change in the machining process lead to the problems of sample missing and insufficiency in the model training stage, which seriously affects the identification accuracy of many AI models. In this paper, a novel identification method based on finite-element modeling (FEM) and the synthetic minority oversampling technique (SMOTE) is proposed to overcome the problem of sample missing and sample insufficiency. Firstly, a few tool wear monitoring experiments are carried out to obtain experimental samples with low cost. Then, a FEM model based on the Johnson−Cook constitutive model was established and verified according to the experimental samples. Based on the verified FEM model, the simulated missing sample i... [more]
Experimental Study on the Working Efficiency and Exergy Efficiency of the Vehicle-Mounted Thermoelectric Generator for Cold Chain Logistics Transportation Vehicle
Yunchi Fu, Yanzhe Li
July 7, 2023 (v1)
Keywords: cold chain logistics transport vehicle, copper foam, logistics and supply chain, thermoelectric generator, working efficiency and exergy efficiency
This paper investigates a vehicle-mounted thermoelectric generator system working efficiency and exergy efficiency in a cold chain logistics transport vehicle (CLVTEG). The study examines the impact of factors such as load resistance, temperature difference, and copper foam on the performance of CLVTEG. Results demonstrate that adding copper foam significantly improves the output power of CLVTEG, with 40 PPI copper foam showing a 1.8 times increase compared to no copper foam. Additionally, copper foam enhances working and exergy efficiency, with 10 PPI copper foam achieving the best overall efficiency. The study also explores the effect of temperature difference on CLVTEGs efficiency, observing an initial increase followed by a decrease. Overall, this research underscores the importance of considering work and exergy efficiency when evaluating thermoelectric generators. Adding copper foam in the CLVTEG central area enhances heat transfer, resulting in improved efficiency. These finding... [more]
Development of a Process to Recycle NdFeB Permanent Magnets Based on the CaO-Al2O3-Nd2O3 Slag System
Ludwig W. Blenau, Daniel Vogt, Oliver Lonski, Abuzar Abrar, Olga Fabrichnaya, Alexandros Charitos
July 7, 2023 (v1)
Keywords: CALPHAD, Nd-rich minerals, neodymium recycling, pyrometallurgical magnet recycling, REPM recycling, slag system design, thermo-calc
Nd, Pr and Dy are critical raw materials as major components for rare earth permanent magnets (REPM). These are integral for several components placed for example within electric vehicles and wind turbine generators. REE primary production is mainly realized in China (~80%) and no REPM recycling industry has been established. Hydrometallurgical recycling routes lead to iron dissolution (66 wt. % Fe in REPM), while pyrometallurgical approaches that utilize SiO2 risk contaminating the produced iron phase. A two-step process is presented that (i) creates an FeOx-CaO-Al2O3-REE2O3 molten slag at 1500 °C through oxidative smelting and (ii) separates an iron-depleted slag phase (CaO-Al2O3-REE2O3) and a molten iron phase via carbothermic or metallothermic reduction at 1700−2000 °C. The slag has been designed as a selective collector phase and the REE2O3 loading within the bulk slag can reach up 25 wt. % REE2O3 at 1700 °C. The contained minerals within the slag exhibit >40 wt. % REE (a higher R... [more]
Investigation on the Catalytic Cracking Mechanism of CuO on Dimethyl Sulfoxide (C2H6OS) and Surface Modification Effects: Insights from Density Functional Theory Calculations
Yan-Qun Wang, Xiang-Long Meng, Hao-Hai Xia, Jian-Zheng Su, Li-Lin Lu, Wei-Chu Yu
July 7, 2023 (v1)
Keywords: catalytic activity, decomposition mechanism, dimethyl sulfoxide, nano copper oxide, oil shale, pyrolysis
To explore the catalytic cracking mechanism of CuO on oil shale and the catalytic activity of surface modifications of CuO on oil shale, dimethyl sulfoxide (C2H6OS) is used as a model molecule representative of organic sulfur compounds in oil shale, and the adsorption and dissociation behaviors of C2H6OS molecules on pure and OH pre-adsorbed CuO(111) surfaces were investigated by density functional theory calculations. The results indicate that C2H6OS selectively adsorbs at the Cusub sites via the S atom and decomposes through cleavage of the C−H bond prior to the breaking of the C-S bond on both surfaces. The presence of OH on the CuO(111) surface promoted the dissociation of C2H6OS. The energy barriers of dehydrogenation and desulfurization of C2H6OS on the OH pre-adsorbed CuO(111) surface were 20.0 and 19.3 kcal/mol, respectively, which are 41% and 49% lower than those on pure surfaces. The present results provide crucial guidance for the synthesis and improvement of high-performanc... [more]
Mathematical Modelling and CFD Simulation for Oxygen Removal in a Multi-Function Gas-Liquid Contactor
Mengdie Wang, Qianqian Nie, Guangyuan Xie, Zhongchao Tan, Hesheng Yu
July 7, 2023 (v1)
Keywords: Computational Fluid Dynamics, degassing, gas-liquid contactor, mass transfer, reactor modelling
This paper presents and compares the mathematical models and computational fluid dynamics (CFD) models for degassing of oxygen from water in a laboratory-scale multi-function gas-liquid contactor under various operating conditions. The optimum correlations of the overall volumetric liquid-phase mass transfer coefficient (kLa) are determined by the mathematical models of specific contactors. Both the continuous-reactor model and semi-batch model can evaluate the degassing efficiency with relative errors within ±13%. Similarly, CFD models agree with experimental data with relative errors of ±10% or less. Overall, the mathematical models are deemed easy to use in engineering practice to assist the selection of efficient contactors and determine their optimum operation parameters. The CFD models have a wider applicability, and directly provide the local mass transfer details, making it appropriate for harsh industrial scenarios where empirical correlations for important quantities are unav... [more]
Effects of Superheated Surface on the Deposition Behavior of Na2SO4 in Supercritical Water
Qiao Zhu, Zhe Li, Yafei Song, Yujun Tong, Tao Yang, Zhenmin Cheng
July 7, 2023 (v1)
Keywords: desalination, supercritical water, surface fouling, temperature effect
The reduced solubility of inorganic salts in supercritical water has a significant impact on the stable operation of desalination facilities as it may lead to surface fouling due to salt deposition. In this study, the solubility of Na2SO4 was experimentally determined to be 0.04−15.34 mmol/kg water at 23−25 MPa and 390−420 °C. To investigate the precipitation behavior of Na2SO4 in supercritical water, a reactor with a heating bar was designed and the deposition effect of salt on the superheated surface in an autoclave was tested at a temperature of 390 °C and a pressure of 23 MPa. Then, the deposition mechanism of salt in the autoclave was analyzed and the temperature field in the reactor was simulated using CFD commercial software. The experimental results showed that Na2SO4 was present on both the heating rod and the bottom of the autoclave with a loose salt layer. The simulation results indicated that the temperature near the heating rod was significantly higher than the bulk fluid... [more]
Geochemical Characteristics and Development Model of the Coal-Measure Source Rock in the Kuqa Depression of Tarim Basin
Xiujian Ding, Tianze Gao, Xianzhang Yang, Zhenping Xu, Changchao Chen, Keyu Liu, Xueqi Zhang
July 7, 2023 (v1)
Subject: Environment
Keywords: coal-measure source rock, depositional environment, input of terrestrial organic matter, Jurassic system, Kuqa Depression, sedimentary rate
The development model of the coal-measure source rock may be different from that of the lacustrine source rock. The depositional environment of the coal-measure source rock is dominated by weak oxidation and weak reduction, and the majority of the organic material originates from terrestrial higher plants. Taking the Jurassic coal-measure source rock in the Kuqa Depression as the research object, the geochemical characteristics of the source rock are comprehensively analyzed, the primary controlling elements of source rock development are made clear, and the development model of the coal-measure source rock is established. This study contributes to the field of source rock prediction and oil and gas exploration. The lithology of the coal-measure source rock in the Kuqa Depression is mainly mudstone, carbonaceous mudstone, and coal, which are medium- to good-quality source rocks, and the organic matter type is mainly II2 and III. Terrestrial organic matter is a key factor in controlling... [more]
Design and Optimization of the Insulation Performance of a 4000 m3 Liquid Hydrogen Spherical Tank
Yang Yu, Fushou Xie, Ming Zhu, Shuai Yu, Yanzhong Li
July 7, 2023 (v1)
Subject: Optimization
Keywords: 4000 m3 LH2 spherical tank, efficient storage, liquid-nitrogen-cooled shield, multilayer insulation, vapor-cooled shield
Efficient insulation technology is one of the key technologies for the development of large LH2 storage tanks. This paper aimed at a 4000 m3 LH2 spherical tank, many insulation schemes were designed, including multilayer insulation systems integrated with a vapor-cooled shield (VCS) and liquid-nitrogen-cooled shield (LN2CS). The heat transfer model was developed to predict the insulation performance of a LH2 spherical tank. The effect of the VCS position on insulation performance was studied, and the different configurations of double VCSs were compared and discussed. The results showed that the daily evaporation rate of MLI, hollow glass microspheres (HGMs) and vacuum was only 2.05 × 10−3%, 3.62 × 10−3% and 7.94 × 10−2% at 1.34 Pa, respectively. MLI was still the optimal insulation scheme for a 4000 m3 LH2 spherical tank. Meanwhile, it was found that when the single VCS was placed at the 10th layer, the heat leakage was reduced by approximately 40.5% compared with MLI. The heat leakag... [more]
Study on Multi-Mode Switching Control of Intelligent Suspension under Full Road Section
Zhaole Qu, Jianze Liu, Yang Li, Fazhan Yang, Jiang Liu
July 7, 2023 (v1)
Keywords: active suspension, adaptive Kalman filtering algorithm, BP-PID control, GA-LQR control, multi-mode switching
The safety, comfort, and energy feedback of active suspension in a single control mode is mutually restricted. To meet the needs of drivers and passengers for vehicle driving performance under different road conditions, this paper proposes a multi-mode switching control strategy of an intelligent suspension system, aiming at improving the stability and comfort of vehicles under different road conditions. In this paper, the adaptive Kalman filter algorithm with a forgetting factor is used to estimate the road input. The accuracy of the algorithm in estimating the road input is verified by simulation and experiment. The single-double threshold logic judgment method is used to formulate the switching rules between each working mode. In the controller, the PID control of the BP neural network and the LQR control optimized by GA are used to optimize and adjust the vehicle driving performance indexes in different modes, which effectively solves the problem of limited adaptability of suspensi... [more]
Design and Performance Evaluation of Liquid-Cooled Heat Dissipation Structure for Lithium Battery Module
Yifei Zhao, Jianhong Chen, Wanrong He
July 7, 2023 (v1)
Keywords: analytic network process, liquid cooling heat dissipation, NCM battery, system dynamics, thermal management scheme
The current global resource shortage and environmental pollution are becoming increasingly serious, and the development of the new energy vehicle industry has become one of the important issues of the times. In this paper, a nickel−cobalt lithium manganate (NCM) battery for a pure electric vehicle is taken as the research object, a heat dissipation design simulation is carried out using COMSOL software, and a charging heat generation model of the battery pack is established. Combined with the related research on the thermal management technology of the lithium-ion battery, five liquid-cooled temperature control models are designed for thermal management, and their temperature control simulation and effect analysis are carried out. Finally, the performance evaluation system of the thermal management scheme of the lithium-ion battery pack is established based on the analytic network process (ANP) and system dynamics (SD), and the performance of the above five thermal management design mo... [more]
Data-Driven Synthesis of a Geometallurgical Model for a Copper Deposit
Yuyang Mu, Juan Carlos Salas
July 7, 2023 (v1)
Keywords: cluster analysis, copper deposit, geometallurgy, Machine Learning, unsupervised learning
Geometallurgy integrates aspects of geology, metallurgy, and mine planning in order to improve decision making in mining schedules. A geometallurgical model is a 3D space that is typically synthesized from early-stage small-scale samples and is composed of several metallurgical units, or domains. This work explores the synthesis of a geometallurgical model for a copper deposit using a purely data-driven unsupervised approach. To this end, a dataset of 1112 drill samples is used, which are clustered using different methods, namely, k-means, hierarchical clustering (AGG), self-organizing maps (SOM), and DBSCAN. Two cluster validity indices (Silhouette and Calinski−Harabasz) are used to select the final model. To validate the potential of the proposed approach, a simulated economic evaluation is conducted. Results demonstrate that k-means exhibits a better performance in terms of modeling and that using the obtained geometallurgical model for mining scheduling increases the project’s Net... [more]
Research on Assembly Method of Threaded Fasteners Based on Visual and Force Information
Yibang Zhou, Xiaoyong Wang, Lanzhu Zhang
July 7, 2023 (v1)
Keywords: compliant control, force sensor, position and orientation estimation, threaded fasteners assembly, vision
Threaded fastening operations are widely used in assembly and are typically time-consuming and costly. In low-volume, high-value manufacturing, fastening operations are carried out manually by skilled workers. The existing approaches are found to be less flexible and robust for performing assembly in a less structured industrial environment. This paper introduces a novel algorithm for detecting the position and orientation of threaded holes and a new method for tightening bolts. First, the elliptic arc fitting method and the three-point method are used to estimate the initial position and orientation of the threaded hole, and the force impact caused by switching from the free space to the constrained space during bolt tightening is solved. Second, by monitoring the deformation of passive compliance, the position information is introduced into the control process to better control the radial force between the bolt and the threaded hole in the tightening process. The constant force contr... [more]
Monitoring Temperature Profile and Drying Kinetics of Thin-Layer Banana Slices under Controlled Forced Convection Conditions
Baher M. A. Amer, Mostafa M. Azam, AbdelGawad Saad
July 7, 2023 (v1)
Keywords: banana, diffusivity, drying kinetics, infrared camera, shrinkage, thin-layer
The drying kinetics of banana slices were examined in a forced convection dryer using an infrared camera to monitor the temperature profile and drying kinetics under control conditions. The air temperature was tested at 40 °C, 50 °C, 60 °C, and 70 °C and the air velocity at 0.2 m/s, 0.5 m/s, and 0.75 m/s, with initial moisture contents of the banana ranging from 76−80% wet basis. The thicknesses of the banana slices being dried were 2, 4, 6, and 8 mm. The optimum drying conditions for the highest drying rate and best color were found to be a temperature of 70 °C, an air velocity of 0.75 m/s, a low relative humidity of 5 to 7%, and banana slices with a thickness of 2 mm. As the air temperature increased, the drying rate and shrinkage also increased. Shrinkage varies concerning moisture loss, and the reduction in radial dimension of banana slices was around 17−23% from the original slice before drying. An empirical mathematical equation was derived by applying the technique of multiple l... [more]
Ataulfo Mango (Mangifera indica L.) Peel Extract as a Potential Natural Antioxidant in Ground Beef
Dalia I. Zafra Ciprián, Guadalupe V. Nevárez Moorillón, Sergio Soto Simental, Ludmila E. Guzmán Pantoja, Luis H. López Hernández, Joaquín T. Santiago Castro, Luz H. Villalobos Delgado
July 7, 2023 (v1)
Keywords: colour stability, ground beef, mango peel extract, natural antioxidants, oxidative stability
Total phenolic content (TPC), total flavonoid content (TFC), antioxidant and antimicrobial in vitro activity of ethanolic (EE) and hydroethanolic (HE) extracts of mango peel Ataulfo were evaluated. The highest TPC, TFC and antioxidant capacity were as shown in EE. Ethanolic extract was incorporated into ground beef at 1000 (BBEA) and 2000 mg/kg meat (BEEB) concentrations and then compared with 250 mg of sodium ascorbate/kg meat (ASC) along with a control (without antioxidant). The effects of adding EE on instrumental colour, metmyoglobin content, thiobarbituric acid reactive substances (TBARS), pH, microbial load and sensorial analysis of ground beef were evaluated for 11 days at 4 °C. BEEB added in raw ground beef improved colour stability while the lipid oxidation in raw and raw-cooked ground beef was inhibited with a greater antioxidant effect than ASC and a similar overall acceptability score (cooked ground beef). However, incorporating BEEB into ground beef did not show significan... [more]
An Artificial Intelligence Method for Flowback Control of Hydraulic Fracturing Fluid in Oil and Gas Wells
Ruixuan Li, Hangxin Wei, Jingyuan Wang, Bo Li, Xue Zheng, Wei Bai
July 7, 2023 (v1)
Keywords: Artificial Intelligence, deep learning neural network, hydraulic fracture, process control
Hydraulic fracturing is one of the main ways to increase oil and gas production. However, with existing methods, the diameter of the nozzle cannot be easily adjusted. This therefore results in ‘sand production’ in flowback fluid, affecting the application of hydraulic fracturing. This is because it is difficult to identify the one-dimensional series signal of fracturing fluid collected on site. In order to avoid ‘sand production’ in the flowback fluid, the nozzle should be properly controlled. Aiming to address this problem, a novel augmented residual deep learning neural network (AU-RES) is proposed that can identify the characteristics of multiple one-dimensional time series signals and effectively predict the diameter of the nozzle. The AU-RES network includes three parts: signal conversion layer, residual and convolutional layer, fully connected layer (including regression layer). Firstly, a spatial conversion algorithm for multiple one-dimensional time series signals is proposed,... [more]
Robust Cascade MRAC for a Hybrid Grid-Connected Renewable Energy System
Juan Carlos Travieso-Torres, Abdiel Ricaldi-Morales, Adolfo Véliz-Tejo, Felipe Leiva-Silva
July 7, 2023 (v1)
Keywords: cascade model reference adaptive control, hybrid grid-connected renewable energy system, nonlinear time-varying systems, robust adaptive control
Hybrid grid-connected renewable energy systems have gained significant importance in sustainably responding to an increased electrical energy demand. These are time-varying nonlinear dynamical plants, where the value of their parameters depends on changing weather conditions and the alternating grid voltage with randomly fluctuating amplitude. This paper proposes a robust cascade MRAC for nonlinear plants representing a class of these systems, which includes n renewable energy converts and a DC/AC single-phase full bridge inverter. The proposal reduces commissioning time by avoiding linearization and knowledge of the plant parameters. Moreover, it includes specific formulas for tuning the controller parameters that decrease their adjustments based on trial and error. Finally, it uses a direct adaptive method with adaptive laws having σθ modification and an inner loop at least five times faster than the outer loop. The proposition validation includes the theoretical stability proof base... [more]
Application of Life Cycle of Aeroengine Mainshaft Bearing Based on Digital Twin
Yunfeng Li, Ming Li, Zhong Yan, Ruoxuan Li, Ao Tian, Xinming Xu, Hang Zhang
July 7, 2023 (v1)
Keywords: aeroengine mainshaft bearing, digital twin, fault diagnosis, grinding process, heat treatment process, life prediction, metallurgical process
Aeroengine mainshaft bearings are key components in modern aeroengines, and their main functions are to support the rotation of the main shaft of the aeroengine in harsh environments, such as high temperature, heavy load, high speed and oil break; reduce the friction coefficient during the high-speed rotation of the main shaft; and reliably ensure the rotation accuracy and power transmission of the aeroengine’s main shaft during operation. The manufacture of aeroengine mainshaft bearings requires complex processes and precise machining to ensure high performance and reliability, and how to intelligently complete the production and manufacture of mainshaft bearings and ensure the strength and accuracy of the bearings, quickly distinguish the fault types of the bearings and efficiently calculate, analyze and predict the life of the bearings are the current research hotspots. Therefore, building a high-fidelity and computationally efficient digital twin life cycle of aeroengine mainshaft... [more]
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