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Showing records 35487 to 35511 of 36336. [First] Page: 1 1417 1418 1419 1420 1421 1422 1423 1424 1425 Last
Research on Driving Factors of Collaborative Integration Implementation of Lean-Green Manufacturing System with Industry 4.0 Based on Fuzzy AHP-DEMATEL-ISM: From the Perspective of Enterprise Stakeholders
Xiaoyong Zhu, Yongmao Xiao, Gongwei Xiao, Xiaojuan Deng
February 21, 2023 (v1)
Keywords: driving factors, enterprise stakeholders, fuzzy AHP-DEMATEL-ISM, Industry 4.0, lean-green manufacturing
The existing research and practices have shown that the coordinated implementation of lean-green manufacturing can have a positive impact on the economic and environmental benefits, which is an effective means to ensure the environmental protection of the production process of manufacturing without damaging their profitability. Within the field of lean-green research, there is still a lack of research to analyze the driving factors for the collaborative implementation of integrated lean and green integration. Although, some scholars and researchers have studied lean and green integration paradigms, their research has mostly focused on lean-green integration practices and their impact on environmental performance and their respective operations. In the context of Industry 4.0, this article investigates the driving forces behind the collaborative integration implementation of a lean-green manufacturing system from the viewpoint of stakeholders. Specifically addressing the issues of corre... [more]
Optimal DGs Siting and Sizing Considering Hybrid Static and Dynamic Loads, and Overloading Conditions
Mariam A. Sameh, Abdulsalam A. Aloukili, Metwally A. El-Sharkawy, Mahmoud A. Attia, Ahmed O. Badr
February 21, 2023 (v1)
Subject: Optimization
Keywords: DGs, dynamic loads, HSA optimization, hybrid loads, static loads
There is no doubt that Distributed Generation (DG) has proved to be an effective solution for satisfying the growing demand within a fleeting period and improving system performance, voltage profile, and power quality, especially on the end user’s side. Thus, in modern distribution systems, DG is preferable to be installed in the vicinity of the end user to enhance the system performance, reduce power losses, and improve grid voltage. In this paper, hybrid static and dynamic load types (100% static, 50% static and 50% dynamic, and 100% dynamic loads) at different overloading conditions, for the standard IEEE 33-bus system, are considered, and power system performance is recorded. Moreover, to improve the power system performance, Distributed Generations (DGs) are optimally sized and allocated in the IEEE 33-bus system using the Harmony Search Algorithm (HSA), and two analytical approaches, respectively, and compared to other reported optimization methods. The results show that, at 100%... [more]
Differences in Physiological Metabolism and Antioxidant System of Different Ecotypes of Miscanthus floridulus under Cu Stress
Jianqiao Qin, Zhiqiang Yan, Xueding Jiang, Huarong Zhao, Shasha Liu, Min Dai, Dexin Xiong, Xi Chen
February 21, 2023 (v1)
Keywords: antioxidant system, copper, Miscanthus floridulus, non-enzymatic substance
To reveal the similarities and differences in the resistance mechanisms of different ecotypes to Cu stress, a pot experiment was used to systematically compare the physiological responses of non-mining ecotype Miscanthus floridulus (collected from Boluo County, Huizhou City) and mining ecotype Miscanthus floridulus (collected from Dabaoshan mining area) under different Cu concentrations. The results showed that chlorophyll a, chlorophyll b and total chlorophyll in the leaves of the two ecotypes of M. floridulus were negatively correlated with Cu stress concentration (p < 0.01), but the extent of decrease for the ecotypes in the mining area was lower than that for the ecotypes in the non-mining area. The values of chlorophyll a/b for both ecotypes increased with increasing Cu treatment concentration, indicating that Cu is more harmful to chlorophyll b than to chlorophyll a for M. floridulus. Cu stress can lead to the accumulation of malondialdehyde (MDA) in the leaves of M. floridulu... [more]
High Efficiency and High Voltage Conversion Ratio Bidirectional Isolated DC−DC Converter for Energy Storage Systems
Yu-En Wu, Kuan-Chi Chen
February 21, 2023 (v1)
Keywords: bidirectional DC–DC converter, three-winding coupled inductor, zero-voltage switching (ZVS)
In this paper, a novel high-efficiency bidirectional isolated DC−DC converter that can be applied to an energy storage system for battery charging and discharging is proposed. By integrating a coupled inductor and switched-capacitor voltage doubler, the proposed converter can achieve isolation and bidirectional power flow. The proposed topology comprises five switches and a common core coupled inductor that uses only a set of complementary pulse-width-modulated signals to control and achieve high voltage gain without requiring high turn ratios or excessive duty cycles. Moreover, the proposed topology can recover the leakage inductance energy to improve the conversion efficiency. The main switches exhibit zero-voltage switching, which reduces the switching losses. A 500-W bidirectional converter is used to verify the feasibility of the proposed bidirectional converter through theoretical analysis and experiments. The experimental results indicate that the highest efficiency of the propo... [more]
Deep Learning Based Target Tracking Algorithm Model for Athlete Training Trajectory
Yue Wang
February 21, 2023 (v1)
Keywords: attention mechanism, deep learning, search strategy, SiamRPN, targettracking algorithm
The main function of the athlete tracking system is to collect the real-time competition data of the athletes. Deep learning is a research hotspot in the field of image and video. With the rapid development of science and technology, it has not only made a breakthrough in theory, but also achieved excellent results in practical application. SiamRPN (Siamese Region Proposal Network) is a single target tracking network model based on deep learning, which has high accuracy and fast operation speed. However, in long-term tracking, if the target is completely obscured and out of the sight of SiamRPN, the tracking of the network will be invalid. Considering the difficulty of long-term tracking, the algorithm is improved and tested by introducing channel attention mechanism and local global search strategy into SiamRPN. Experimental results show that this algorithm has higher accuracy and prediction average overlap rate than the original SiamRPN algorithm when performing tracking tasks on lon... [more]
A Data-Driven Fine-Management and Control Method of Gas-Extraction Boreholes
Xiaoyang Cheng, Haitao Sun
February 21, 2023 (v1)
Keywords: borehole design, borehole repair, gas extraction, refined management
In order to improve the efficiency of gas extraction in coal mines, a data-driven fine-management and control method for gas extraction is proposed. Firstly, the accurate prediction of coal seam thickness and gas content was used to evaluate the gas reserves. Based on the time relationship between mining activities and gas extraction, the calculation model of borehole distance in different extraction units is established, and the differential borehole design is realized. Then, a drilling video-surveillance system and drilling trajectory measurement device are used to control the drilling process and the construction effect. Finally, the model of extraction data-correction and the identification of failed boreholes is established, then the failed boreholes are repaired. The technology method provided in the paper has realized the fine control of gas-extraction borehole design, construction, measurement, and repair, and formed a more scientific gas-extraction borehole control technology... [more]
Pilot-Plant-Scale Extraction of Antioxidant Compounds from Lavender: Experimental Data and Methodology for an Economic Assessment
Encarnación Cruz Sánchez, Jesús Manuel García-Vargas, Ignacio Gracia, Juan Francisco Rodríguez, María Teresa García
February 21, 2023 (v1)
Keywords: antioxidant potential, economic evaluation, financial analysis, lavender essential oil, price curve, supercritical fluid extraction (SFE)
The techno-economic feasibility of lavender essential oil supercritical CO2 extraction was studied. The process was scaled up to a pilot plant, and the extraction yield, composition, and antioxidant potential of the extracts were evaluated at 60 °C and 180 bar or 250 bar, achieving a maximum yield of 6.9% and a percentage inhibition of the extracts of more than 80%. These results drove the development of a business plan for three scenarios corresponding to different extraction volumes (20, 50, and 100 L) and annual production. The SWOT matrix showed that this is a promising business idea. The COM was calculated and an investment analysis was performed. The profitability of this process was demonstrated by means of a financial analysis for 8 years, considering a selling price of 1.38 EUR/g for the extract from the 20 L plant and 0.9 EUR/g for industrial-scale plants, supported by the price curve. The sensitivity analysis showed that the price of the equipment was the factor that could m... [more]
Discrete and Continuous Glucose Monitoring Systems: The Point of View of a Patient Affected by Type-1 Diabetes
Paolo Trucillo
February 21, 2023 (v1)
Keywords: carbohydrates, continuous glucose monitoring, delivery systems, glucose levels, glycosylated hemoglobin, insulin administration
This work represents the point of view of a diabetic patient with an indirect experience in this specific field of research. As a chemical engineer and researcher in drug carrier production, he has always approached type-1 diabetes (T1D) in a scientific manner. Therefore, this work represents a description of almost 20 years of this illness treatment using a multi-injection insulin system, compared with the experience acquired with a newly adopted micro-infusion system, allowing automatized insulin administration. The use of the continuous system reduced significantly the Hb1Ac average values, from 8.8% to 6.6%, in less than 2 years. Moreover, a full 24 h control guaranteed the almost total elimination of the hypoglycemia risk, thanks to the automated control system, that can stop insulin administration in order to prevent critical situations. It is also important to note that the point of view underlined in this work does not presume to be that of a doctor or of a researcher who works... [more]
Modelling of Propylene Polymerization in a Loop Reactor on the Titanium−Magnesium Catalyst Taking into Account the Transformation of Active Centers
Galiya Manuyko, Veronika Bronskaya, Olga Kharitonova, Tatiana Ignashina, Dmitriy Bashkirov, Denis Balzamov, Vladimir Pliushchev, Ramiliya Shaikhetdinova
February 21, 2023 (v1)
Keywords: catalyst, polymerization, polypropylene synthesis process
The volume of consumed and produced polymers is increasing in the market every day. This is due to the indispensability and convenience of polymers in all industries. The article presents the distinctive features of the use of titanium−magnesium catalysts in the process of propylene polymerization. A mathematical model of the polypropylene polymerization is presented. This model is the basis of creating an expert control complex of the propylene−ethylene block copolymer (PEBC) synthesis process and allowing a quantitative connection to be made between technological parameters of reactors, which allows control of the technological mode with the acceptable accuracy. The experiment catalytic system is microspheric titanium trichloride (MS-TiCl3) and co-catalyst-diethylaluminum chloride. Dependences of different parameters on others are illustrated. The result of the research is as follows: according to the calculations, when increasing the number of blocks in the chain, the average values... [more]
Optimization of Grinding Process of Sunflower Meal for Obtaining Protein-Enriched Fractions
Strahinja Vidosavljević, Nemanja Bojanić, Petar Ilić, Dušan Rakić, Olivera Đuragić, Vojislav Banjac, Aleksandar Fišteš
February 21, 2023 (v1)
Subject: Biosystems
Keywords: hammer mill, Optimization, protein content enrichment, roll mill, sunflower meal
In this study, dry fractionation process was proposed in order to obtain protein-enriched sunflower meal fractions. The process includes two-stage grinding using a hammer mill and a roll mill, and fractionation of sunflower meal by sieving. Central composite design (CCD) with four variables on three levels within response surface methodology was applied in order to estimate the influence of grinding parameters (sieve openings diameter of the hammer mill: 2, 4, and 6 mm, roll gap: 0.15, 0.2, and 0.25 mm, feed rate: 0.1, 0.175, and 0.25 kg/cm min, and roll speed: 400, 500, and 600 rpm) on responses (protein content, fraction yield and grinding energy consumption). Sieve openings diameter expressed the highest impact on fraction yield while roll gap expressed the most dominant influence on protein content in the fraction and grinding energy consumption. The highest protein content obtained was 48.06%(dm) with fraction yield of 77.22%. A multi-response optimization procedure was performed... [more]
Dynamic Chaotic Opposition-Based Learning-Driven Hybrid Aquila Optimizer and Artificial Rabbits Optimization Algorithm: Framework and Applications
Yangwei Wang, Yaning Xiao, Yanling Guo, Jian Li
February 21, 2023 (v1)
Keywords: adaptive switching mechanism, Aquila Optimizer, Artificial Rabbits Optimization, chaotic opposition-based learning, industrial engineering design, photovoltaic model
Aquila Optimizer (AO) and Artificial Rabbits Optimization (ARO) are two recently developed meta-heuristic optimization algorithms. Although AO has powerful exploration capability, it still suffers from poor solution accuracy and premature convergence when addressing some complex cases due to the insufficient exploitation phase. In contrast, ARO possesses very competitive exploitation potential, but its exploration ability needs to be more satisfactory. To ameliorate the above-mentioned limitations in a single algorithm and achieve better overall optimization performance, this paper proposes a novel chaotic opposition-based learning-driven hybrid AO and ARO algorithm called CHAOARO. Firstly, the global exploration phase of AO is combined with the local exploitation phase of ARO to maintain the respective valuable search capabilities. Then, an adaptive switching mechanism (ASM) is designed to better balance the exploration and exploitation procedures. Finally, we introduce the chaotic op... [more]
Building a Digital Twin Simulator Checking the Effectiveness of TEG-ICE Integration in Reducing Fuel Consumption Using Spatiotemporal Thermal Filming Handled by Neural Network Technique
Ahmed M. Abed, Laila F. Seddek, Samia Elattar
February 21, 2023 (v1)
Keywords: damage detection, digital twin, influencing factors, non-destructive testing, Optimization, thermal filming, waste heat recovery
Scholars seek to recycle wasted energy to produce electricity by integrating thermoelectric generators (TEGs) with internal combustion engines (ICE), which rely on the electrical conductivity, β, of the thermal conductor strips. The TEG legs are alloyed from iron, aluminum and copper in a strip shape with specific characteristics that guarantee maximum thermo-electric transformation, which has fluctuated between a uniform, Gaussian, and exponential distribution according to the structure of the alloy. The ICE exhaust and intake gates were chosen as the TEG sides. The digital simulator twin model checks the integration efficiency through two sequential stages, beginning with recording the causes of thermal conductivity failure via filming and extracting their data by neural network procedures in the feed of the second stage, which reveal that the cracks are a major obstacle in reducing the TEG-generated power. Therefore, the interest of the second stage is predicting the cracks’ positio... [more]
Development of a Continuous Hydrothermal Treatment Process for Efficient Dewatering of Industrial Wastewater Sludge
Douwe S. Zijlstra, Esther Cobussen-Pool, Dennis J. Slort, Mark Visser, Pavlina Nanou, Jan R. Pels, Heather E. Wray
February 21, 2023 (v1)
Keywords: biological paper sludge, dewatering, hydrothermal carbonization, industrial wastewater, TORWASH
Sludges from the papermaking industry represent a challenging residue stream that is difficult to dewater using conventional processes. The successful development and scale-up of innovative processes from lab- to pilot- to industrial-scale are required to tackle challenges for waste treatment, including paper sludges. Biological paper sludge was treated via a mild hydrothermal carbonization process (TORWASH®) to improve dewaterability of the sludge, including long-duration, continuous testing. Initial lab-scale experiments indicated the optimal treatment temperature for sludge dewatering was 190 °C. Dewaterability improved with increasing temperature, but the obtained solid yield decreased. Scaling-up to a continuous flow pilot plant required a temperature of 200 °C to achieve optimum dewatering. Pilot-scale hydrothermal treatment and dewatering resulted in solid cakes with an average dry matter content of 38% and a solid yield of 39%. This study demonstrates the benefits of hydrotherm... [more]
Efficient Adsorption of Tl(I) from Aqueous Solutions Using Al and Fe-Based Water Treatment Residuals
Youze Xu, Yingjun Qing, Ruimin Gu, Shuang Zhou, Guangyi Fu, Yuanyuan Zhao
February 21, 2023 (v1)
Keywords: Adsorption, Al-WTR, Fe-WTR, thallium, wastewater treatment
Iron and aluminum water treatment residuals from a water supply plant were used as adsorbents for Tl(I) to treat thallium-containing Tl(I) wastewater and realize the resource utilization of water treatment residuals. The feasibility study results showed that Fe-WTR and Al-WTR reached adsorption equilibria within 120 min. The Langmuir model showed maximum adsorption capacities of Tl(I) on Fe-WTR and Al-WTR as 3.751 and 0.690 mg g−1 separately at an initial concentration of 5 mg L−1. The adsorption capacities of Fe-WTR and Al-WTR positively correlated with pH. The removal of Tl(I) using Fe-WTR exceeded Al-WTR; the adsorbed Tl(I) in Fe-WTR occurred primarily in the reduced state, while the Tl(I) adsorbed in Al-WTR was mainly in acid-extractable and reduced states. FTIR and XPS data showed that Tl(I) and Fe/Al-OH-functional groups formed stable surface complexes (Fe/Al-O-Tl) during adsorption, and there was no redox reaction. This confirmed that WTR is a highly efficient adsorbent for the... [more]
Validation of a Classical Sliding Mode Control Applied to a Physical Robotic Arm with Six Degrees of Freedom
Andres González-Rodríguez, Rogelio E. Baray-Arana, Abraham Efraím Rodríguez-Mata, Isidro Robledo-Vega, Pedro Rafael Acosta Cano de los Ríos
February 21, 2023 (v1)
Keywords: manipulator, real-time application, six degrees of freedom, sliding mode control
The control of robotic manipulators has become increasingly difficult over recent years due to their high accuracy, performance, speed, and reliability in a variety of applications, such as industry, medicine, research, etc. These serial manipulator systems are extremely complex because their dynamic models include perturbations, parametric variations, coupled nonlinear dynamics, and non-modular dynamics, all of which require robust control for trajectory tracking. This paper compares two control techniques: computational torque control (CTC) and sliding mode control (SMC). In this study, the latter was used for a physical robotic arm with six degrees of freedom (DOF) and online experiments were conducted, which have received little attention in the literature. As a result, the contribution of this work was based on the real-time application of this controller via a self-developing interface. The great resilience of sliding mode controllers to disturbances was also demonstrated in this... [more]
Experimental Characterization of a Microfluidic Device Based on Passive Crossflow Filters for Blood Fractionation
Inês M. Gonçalves, Inês Castro, Filipe Barbosa, Vera Faustino, Susana O. Catarino, Ana Moita, João M. Miranda, Graça Minas, Patrícia C. Sousa, Rui Lima
February 21, 2023 (v1)
Subject: Materials
Keywords: blood analogue, blood on chip, cell separation, crossflow microfluidic device, optical absorbance spectrophotometry, passive microfluidic device
The separation of red blood cells (RBCs) from blood plasma and the analysis of individual RBCs are of great importance, as they provide valuable information regarding the health of their donor. Recent developments in microfluidics and microfabrication have contributed to the fabrication of microsystems with complex features to promote the separation and analysis of RBCs. In this work, the separation capacity of a multi-step crossflow microfluidic device was evaluated by using a blood analogue fluid made by Brij L4 micelles and human RBCs separated from whole blood, suspended in a solution with hematocrits (Ht) of 0.5 and 1%. All the samples collected at the outlets of the device were experimentally analyzed and compared. The absorbance spectrum was also measured for the prepared blood samples. The results indicate that the tested blood analogue fluid has exhibited a flow behavior similar to that of blood. In addition, the optical absorbance spectrophotometry revealed that it was possib... [more]
Effects of Reynolds Number on the Overall Characteristics of Flow and Heat Transfer in the Long Micro-Tube with Dimples
Ruibai Qi, Fangfang Chen, Linjie Xu, Jiawen Yu, Xiaoping Chen
February 21, 2023 (v1)
Keywords: flow, heat transfer, micro-tube, Reynolds number
The flow and heat transfer characteristics in micro-tube are very important research fields. In order to study the influence of the Reynolds number on the overall characteristics of flow and heat transfer, a 510 mm long micro-tube with dimples was constructed. Thirty-five different working conditions are considered, and the Reynolds number is between 1500 and 8100. At the same time, the change of physical properties of coolant with temperature is considered. The reliability of numerical simulation results is verified by the grid independence verification and the comparison of experimental data. The results show that the dimple will promote the instability of the flow state and improve the heat transfer efficiency. The flow state evolution formed in the stream-wise direction is basically similar, and its fully developed position remains at 76 mm, which is independent of the Reynolds number. For the fully developed region, the partial derivation of static pressure in the stream-wise comp... [more]
Simulated Handling to Investigate the Effect of Mechanical Damage on Stored Pomegranate Fruit
Pankaj B. Pathare, Mai Al-Dairi, Rashid Al-Yahyai, Adil Al-Mahdouri
February 21, 2023 (v1)
Keywords: bruising, mechanical damage, pendulum test, storage, titratable acidity
Mechanical damage is a threat to both food security and sustainability. Bruising is the most common type of mechanical damage, and it causes a huge economic loss due to rejection of fresh produce and downgrading of the appearance quality by consumers. Therefore, this study aims to examine the effect of bruising during postharvest handling using a pendulum test technique. Pomegranate fruit were bruised once at two impact levels (1.189 ± 0.109 and 2.298 ± 0.239 J) and then stored (at 5 °C ± 1 °C and 22 °C ± 1 °C) for 28 days. The study evaluated the effect of impact bruising, storage temperature, and duration on the bruise magnitude and quality attributes of the bruised and non-bruised pomegranates. The results showed that the investigated factors affect the bruise size of bruised pomegranates. Increasing storage temperature from 5 to 22 °C and impact level from 1.189 to 2.298 J increased the bruise area, bruise volume, and bruise susceptibility over time. Alterations in total soluble so... [more]
Exploration of Cucumber Waste as a Potential Biorefinery Feedstock
Yang Gao, Hannah K. Briers, Avtar S. Matharu, Jiajun Fan
February 21, 2023 (v1)
Subject: Materials
Keywords: biorefinery, cellulosic materials, cucumber, essential oils, hydro-distillation, vacuum microwave hydro-distillation
The exploration of cucumber waste as a potential biorefinery feedstock is reported. Initially, extractives (essential oils) were isolated from cucumber waste via vacuum microwave hydro-distillation (VMHD). The yield and quality of the extractive were compared with respect to traditional hydro-distillation (HD). The essential oils were obtained over a range of microwave power (500, 750, 1000 W) and vacuum pressures (100, 200, 300 mbar). The highest quality (0.49 wt %) was obtained at a microwave irradiation power of 500 W and a vacuum of 300 mbar. VMHD is much quicker and more energy-efficient than HD. Within the context of a zero-waste biorefinery, the extractive-free residues were the solid residues from two different extraction methods were compared and characterized by ATR-IR, 13C solid-state NMR spectroscopy, SEM, TGA, and CHN elemental analysis. The resultant residues are cellulosic-rich, and no significant changes were observed with VMHD and HD treatment. The results indicated th... [more]
Insight into the Acidity and Catalytic Performance on Butane Isomerization of Thermal Stable Sulfated Monoclinic Zirconia
Daofeng Huang, Wenhua Feng, Li Zhang, Bin Yue, Heyong He
February 21, 2023 (v1)
Subject: Materials
Keywords: butane isomerization, monoclinic, solid-state NMR, sulfated zirconia
Sulfated monoclinic zirconia (M-SZ) with high thermal stability and high catalytic performance on butane isomerization were obtained by hydrothermal method followed with sulfation treatment. The acidity of M-SZ was studied by 31P MAS NMR, with trimethylphosphine (TMP) as the probe molecule, and the catalytic performance of 1-13C-n-butane over M-SZ was monitored by 13C MAS NMR spectroscopy. Both Brønsted and Lewis acids were observed on M-SZ. Only Brønsted acid strength shows close relation to the activation energy of butane isomerization, and the M-SZ catalyst with the strongest Brønsted acid strength shows the lowest activation energy of 46.4 kJ·mol−1. The catalytic stability tests were evaluated at 673 K for 240 h, which shows that sulfated monoclinic zirconia has higher thermal stability than sulfated tetragonal zirconia.
Potential Efficacy of Bacillus coagulans BACO-17 to Modulate Gut Microbiota in Rats Fed High-Fat Diet
Zu Chan, Chiou-Yeong Saw, Yi-Ching Wu, Der-Kai Lau, Wei-Jen Chen, Hui-Fang Chu, Cheng-Yen Liu, Ai-Lun Tseng, Chi-Fai Chau
February 21, 2023 (v1)
Keywords: Bacillus coagulans BACO-17, fat accumulation, high-fat diet, microbiota
This study aimed to evaluate the potential efficacy of Bacillus coagulans BACO-17 in ameliorating body fat accumulation as well as gut microbiota dysbiosis in animals, which were given a high-fat diet to mimic the adverse effect of an unhealthy dietary pattern. Compared with normal control, high-fat consumption resulted in significant (p < 0.05) elevations in weight gain (168%), feed efficiency (176%), visceral fat accumulation (228%), and a lesser total fecal short-chain fatty acids (SCFAs) (−27.5%). A significant shift of fecal Fimicutes:Bacteroidetes ratio from 1.13 to 3.14 was also observed. After 12 weeks of experiment, a supplementation of B. coagulans BACO-17 at high dose (9 log CFU/day) along with a high-fat diet could exert an apparent fat reduction ability by decreasing weight gain (by 23.7%) and visceral fat mass (by 24.0%). It was found that B. coagulans BACO-17 was able to increase fecal SCFA concentrations and revert Fimicutes:Bacteroidetes ratio back to the level... [more]
Study of the Dynamic Behavior of an Autonomous Inflow-Control Device Using a Digital Twin
Luis Alfonso Ramirez Cerquera, Jorge Andrés Pinilla, Nicolás Ríos Ratkovich, Miguel Asuaje
February 21, 2023 (v1)
Keywords: Computational Fluid Dynamics, heavy oil, inflow-control device, RCP, water management
Solutions that aim to reduce water production in heavy oil wells have led to the design of devices known as rate-controlled production (RCP) autonomous inflow-control device (AICD) valves, which are placed in well completions and autonomously open with the oil inflow and close with water by choking the flow. These devices, which are based on Bernoulli’s principle, use a levitating disk that chokes the flow of the phase with the lowest flow resistance. This study proposes a numerical model based on computational fluid dynamics (CFD) technology to understand these devices’ operations and propose better designs without experimentation. The numerical model was based on dynamic fluid−body interaction (DFBI) and volume of fluid (VOF) models. The model was found to respond as expected depending on the physical properties of the fluids involved in heavy oil production. Finally, some limitations were found in the numerical study that can be improved in future studies.
Unsteady Mass Transfer in Bubble Wakes Analyzed by Lagrangian Coherent Structures in a Flat-Bed Reactor
Lotta Kursula, Felix Kexel, Jürgen Fitschen, Marko Hoffmann, Michael Schlüter, Alexandra von Kameke
February 21, 2023 (v1)
Keywords: flat-bed reactor, gas-liquid reactions, Lagrangian Coherent Structures, mass transfer phenomena, reactive bubbly flows
To increase the yield and selectivity in reactive bubbly flows, the gas-liquid interactions have to be understood in depth. In the current fundamental study, flow and concentration data of the wakes of two-dimensional bubbles in an organic solvent are obtained experimentally in a flat-bed reactor. The unsteady mass transport phenomena in these turbulent wakes of two freely rising, two-dimensional bubbles with bubble Reynolds numbers Re=949 and Re=388 are evaluated by analyzing Lagrangian Coherent Structures (LCS). To reveal how LCS govern the transport of dissolved gas in bubble wakes, and therefore affect gas-liquid reactions, LCS in two-dimensional velocity fields are computed and compared with concentration fields of dissolved gas. The analysis of backward Finite Time Lyapunov Exponent (bFTLE) fields reveals coherent fluid dynamic structures for both bubble Reynolds numbers studied. In the higher bubble Reynolds number case, two types of coherent structures are found, which hinder t... [more]
Research on the Application of Coal Gasification Slag in Soil Improvement
Ruimei Zhang, Xiaonan Li, Kai Zhang, Pengfei Wang, Peifeng Xue, Hailong Zhang
February 21, 2023 (v1)
Keywords: coal gasification slag, contaminant analysis, microscopic characterization
SEM, particle size analysis, and contaminant content of coarse coal gasification slag (CCGS) produced by Shenhua Xinjiang Chemical Co., Ltd. were measured, respectively, and the physicochemical properties of the soil after improvement using gasification slag were investigated in this paper. The results showed that the slag was porous, the particle size was small and the pollutant content was extremely low. Its pollutants were closely related to the pollutants in the raw coal. The coarse slag had a limited effect on soil particle size and texture improvement; the soil water retention performance increased with the increase of proportion of the slag, while pH and conductivity decreased; the improvement effect on soil SOM and available potassium was remarkable; the larger the proportion of the slag, the stronger the effect on maintaining soil alkali-hydrolyzed nitrogen, ammonium nitrogen, and available phosphorus. However, the effect was small, and increased the ion content, especially th... [more]
ZIF for CO2 Capture: Structure, Mechanism, Optimization, and Modeling
Kishor Kalauni, Ajitanshu Vedrtnam, Magdalena Wdowin, Shashikant Chaturvedi
February 21, 2023 (v1)
Keywords: characterisation, CO2 absorption, metal-organic framework, zeolites, ZIF
The requirement to counter carbon emissions is becoming urgent. Zeolitic Imidazolate Frameworks (ZIFs) have been extensively investigated recently for storing and separating gases, especially carbon dioxide. The present review aims to summarise the state of the art of ZIFs for carbon dioxide capture focusing on the structure, mechanism, optimisation, and modelling. The methods utilised for carbon capture are briefly summarized. The morphology of ZIFs with different topologies, N2-CO2 adsorption-desorption isotherms, X-ray diffraction patterns, thermo-gravimetric analysis (TGA) results are discussed to give insights into the textural properties, structure-activity relationship and structural-thermal stability of ZIFs. Finally, the experimental optimisation techniques, modelling and simulation studies for improving CO2 capture by ZIFs are discussed. This review should provide a comprehensive and quick understanding of this research area. It is timely to summarize and review ongoing devel... [more]
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