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Showing records 1529 to 1553 of 43292. [First] Page: 1 59 60 61 62 63 64 65 66 67 Last
Determining Optimal Assembly Condition for Lens Module Production by Combining Genetic Algorithm and C-BLSTM
Hyegeun Min, Yeonbin Son, Yerim Choi.
June 6, 2024 (v1)
Subject: Optimization
Keywords: convolutional–bidirectional long short-term memory, Genetic Algorithm, lens module, lens module production, optimal assembly condition, part lens assembly.
Mobile camera modules are manufactured by aligning and assembling multiple differently shaped part lenses. Therefore, selecting the part lenses to assemble from candidates (called cavities) and determining the directional angle of each part lens for assembly have been important issues to maximize production yield. Currently, this process is manually conducted by experts at the manufacturing site, and the manual assembly condition optimization carries the risk of reduced production yield and increased failure cost as it largely depends on one’s expertise. Herein, we propose an AI framework that determines the optimal assembly condition including the combination of part lens cavities and the directional angles of part lenses. To achieve this, we combine the genetic algorithm with convolutional bidirectional long-term short-term memory (C-BLSTM). To the best of our knowledge, this is the first study on lens module production finding the optimal combination of part lens cavities and direct... [more]
Optimization of Exergy Efficiency in a Walking Beam Reheating Furnace Based on Numerical Simulation and Entropy Generation Analysis
Dijie Wang, Xinru Zhang, Youxin Zhu, Zeyi Jiang.
June 6, 2024 (v1)
Keywords: entropy generation, exergy efficiency optimization, heat transfer, numerical simulation, reheating furnace.
An analysis of entropy generation and exergy efficiency can effectively explore the energy-saving potential of reheating furnaces. This paper simulated the combustion, flow, and heat transfer in a walking beam reheating furnace by establishing a half-furnace model. The entropy generation rate distribution of different thermal processes was numerically calculated. The effect of slab residence time and fuel distribution in the furnace was studied to optimize exergy efficiency. The results indicated that combustion and radiative heat transfer are the primary sources of entropy generation. Irreversible losses accounted for 26.39% of the total input exergy, in which the combustion process accounted for 16.43%, and radiative heat transfer accounted for 8.47%. Reducing the residence time by 60 min decreased irreversible exergy loss by about 2.5% but increased heat dissipation and exhaust exergy loss by 5.8%. Energy saving can only be achieved when the heat exchanger’s exergy recovery efficien... [more]
New Approach to the Analysis of Manufacturing Processes with the Support of Data Science
Martin Krajčovič, Vsevolod Bastiuchenko, Beáta Furmannová, Milan Botka, Dávid Komačka.
June 6, 2024 (v1)
Keywords: data analysis, information systems, methodical procedure, process maps, process mining.
This article introduces process mining as an innovative approach to enterprise data analysis, offering a systematic method for extracting, analyzing, and visualizing digital traces within information systems. The technique establishes connections within data, forming intricate process maps that serve as a foundation for the comprehensive analysis, interpretation, and enhancement of internal business processes. The article presents a methodical procedure designed to analyze processes using process mining. This methodology was validated through a case study conducted in the Fluxicon Disco software (version 3.6.7) application environment. The primary objective of this study was to propose and practically validate a methodical procedure applied to industrial practice data. Focusing on the evaluation and optimization of manufacturing processes, the study explored the integration of a software tool to enhance efficiency. The article highlights key trends in the field, providing valuable insi... [more]
Analysis of Influencing Factors of Slippage and the Dynamic Process of Fault Slip Caused by Multi-Stage Fracturing
Zongyu Lu, Wei Lian, Jun Li, Nenghao Wang.
June 6, 2024 (v1)
Keywords: casing deformation, fault slippage, multi-stage fracturing, shale oil and gas wells.
Casing deformation is evident during the development of shale oil and gas wells in the Sichuan and Junggar Basins in China. Their casing deformation characteristics, distribution law of deformation points, and main controlling factors were analyzed. According to the analysis results, shear is the main cause of casing deformation of shale oil and gas wells in the Sichuan and Junggar Basins in China and has the characteristics of “a dense heel end and a sparse toe end”. Faults account for 75% of casing deformation points, and fault slip caused by multi-stage fracturing is the primary factor responsible. The calculation model for fault slip that takes into account fracturing fluid invasion was established, and the dynamic variation law of fault slip was clarified: the fracturing fluid intruded into the fault, the relative dislocation of the damaged fault was caused by gravity, and the fault slippage was caused by the increase in fault activation length. This resulted in a linear increase... [more]
Co-Injection of Foam and Particles: An Approach for Bottom Water Control in Fractured-Vuggy Reservoirs
Jianhai Wang, Yibo Feng, Aiqing Cao, Jingyu Zhang, Danqi Chen.
June 6, 2024 (v1)
Keywords: flow characteristic, fractured-vuggy reservoir, particle, plugging, polymer foam.
Fractured-vuggy carbonate reservoirs are tectonically complex; their reservoirs are dominated by holes and fractures, which are extremely nonhomogeneous and are difficultly exploited. Conventional water injection can lead to water flooding, and the recovery effect is poor. This paper takes the injection of foam and solid particles to control bottom water as the research direction. Firstly, the rheological properties of foam were studied under different foam qualities and the presence of particles. The ability of foam to carry particles was tested. By designing a microcosmic model of a fractured-vuggy reservoir, we investigated the remaining oil types and the distribution caused by bottom water. Additionally, we analyzed the mechanisms of remaining oil mobilization and bottom water plugging during foam flooding and foam−particle co-injection. The experimental results showed that foam was a typical power-law fluid. Foam with a quality of 80% had good stability and apparent viscosity. Dur... [more]
Configuration Strategy and Performance Analysis of Combined Heat and Power System Integrated with Biomass Gasification, Solid Oxide Fuel Cell, and Steam Power System
Xinyao Zhu, Zeqiu Li, Ying Tian, Xiuhui Huang.
June 6, 2024 (v1)
Keywords: biomass gasification, configuration strategy, solid oxide fuel cell (SOFC), steam power system (SPS).
Renewable energy integration is a crucial approach for achieving a low-carbon energy supply in industrial utility systems. However, the uncertainty of user demand often leads to a mismatch between the system’s real operating conditions and the optimal operating points, resulting in energy wastage and high emissions. This study presents a multi-source heat and power system that integrates biomass gasification, solar collecting, solid oxide fuel cell (SOFC), gas turbine, and steam power systems. A scheduling strategy that varies the heat-to-power ratio is proposed to accommodate changes in user requirements. A simulation model of this multi-source system is established and validated. The influence of three key parameters on system performance under different configurations is explored. Energy and economic evaluations are conducted for three different configurations, and the system’s energy production and adjustable range are determined. The analysis reveals that, under the optimal config... [more]
A Finite-Element-Analysis-Based Feasibility Study for Optimizing Pantograph Performance Using Aluminum Metal Matrix Composites
Masengo Ilunga, Abhishek Agarwal.
June 6, 2024 (v1)
Keywords: aluminum MMC, CAD model, equivalent stress, FEA simulation, feasibility analysis, metal matrix composites (MMCs), pantograph, strain energy, structural enhancement.
A pantograph is a key component on the tops of trains that allows them to efficiently tap electricity from power lines and propel them. This study investigates the possibility of using metal matrix composites (MMCs), specifically aluminum MMCs, as a material for making pantograph parts regarding the dynamics of the train’s movement and external meteorological conditions. In this study, a computer-aided design (CAD) model is created using PTC Creo design software and moves to detailed finite element analysis (FEA) simulations executed by the ANSYS software suite. These simulations are important in examining how the dynamic performance of pantographs can vary. The incorporation of Al MMC materials into the structure of the pantograph resulted in significant improvements in structural robustness, with equal stress reduced by up to 0.18%. Similarly, aluminum MMC materials reduced the strain energy by 0.063 millijoules. The outcomes not only give a new perspective to the implementation of m... [more]
A Numerical Study on the Process of the H2 Shaft Furnace Equipped with a Center Gas Distributor
Shan Yu, Lei Shao, Zongshu Zou.
June 6, 2024 (v1)
Keywords: center gas distributor, CO2-lean steelmaking, gas utilization, H2 shaft furnace, solid reduction degree.
In order to explore technically feasible options for improving the performance of the H2 shaft furnace (HSF), a previously built and validated computational fluid dynamics (CFD) model was employed in the current work to assess the potential of the operation based on a center gas distributor (CGD). A set of simulations was performed to mimic scenarios where different amounts of feed gas (0−30% of 1400 Nm3/t-pellet) are injected via the CGD located at the bottom of the HSF. The results showed that a relatively large stagnant zone (approximately 8.0-m in height and 0.3-m in diameter) exists in the furnace center where the gas flows are weak owing to an overly shortened penetration depth of the H2 stream solely injected from the circumferentially installed bustle-pipe. When adopting the CGD operation, however, the center gas flows can be effectively enhanced, consequently squeezing the stagnant zone and thus leading to a better overall performance of the HSF. In particular, the uniformity... [more]
Preparation of PVA/SA-FMB Microspheres and Their Adsorption of Cr(VI) in Aqueous Solution
Jinlong Zuo, Jin Ren, Liming Jiang, Chong Tan, Junsheng Li, Zhi Xia, Wei Wang.
June 6, 2024 (v1)
Subject: Materials
Keywords: Adsorption, biochar, Cr(VI), sodium alginate microspheres.
Biochar, a carbon-dense material known for its substantial specific surface area, remarkable porosity, diversity of functional groups, and cost-effective production, has garnered widespread acclaim as a premier adsorbent for the elimination of heavy metal ions and organic contaminants. Nevertheless, the application of powdered biochar is hindered by the challenges associated with its separation from aqueous solutions, and without appropriate management, it risks becoming hazardous waste. To facilitate its use as an immobilization medium, biochar necessitates modification. In this investigation, sodium alginate, celebrated for its superior gelation capabilities, was amalgamated with polyvinyl alcohol to bolster mechanical robustness, thereby embedding biochar to formulate sodium alginate biochar microspheres (PVA/SA-FMB). A meticulously designed response surface methodology experiment was employed to ascertain the optimal synthesis conditions for PVA/SA-FMB. Characterization outcomes un... [more]
Influence of Mining Sequence of Branch on Stope Pressure Behaviour on Continuous Mining and Continuous Backfilling
Hai Lin, Yang Yang, Cheng Chen, Chenxi Ding.
June 6, 2024 (v1)
Keywords: continuous mining and continuous backfilling, mining sequences, stress distribution, surrounding rock control.
Instability in coal pillars and filling bodies is a common occurrence during the mining process of continuous mining and continuous backfilling (CMCB). In view of this, combining numerical simulation, similarity simulation, and on-site testing approaches, backfill mining models were established in Flac3d5.01 software, similarity model test bench, and “two-stage”, “three-stage”, and “four-stage” mining sequences were conducted; the stress characteristics of coal pillar-filling body and the displacement evolution law of surrounding rock have been compared under three typical mining sequences. The results show that compared to two-stage mining sequence, three-stage and four-stage mining sequences provide sufficient time for the solidification of the filling body. The coal pillar exhibits better stability in the early stage of mining, but the stress concentration phenomenon is more significant in the later stage of mining. The stress concentration coefficient is the highest when the width... [more]
The Prediction of Flow Stress in the Hot Compression of a Ni-Cr-Mo Steel Using Machine Learning Algorithms
Tao Pan, Chengmin Song, Zhiyu Gao, Tian Xia, Tianqi Wang.
June 6, 2024 (v1)
Keywords: constitutive model, error evaluation, flow stress, hot deformation, machine learning algorithm, Ni-Cr-Mo steel.
The constitutive model refers to the mapping relationship between the stress and deformation conditions (such as strain, strain rate, and temperature) after being loaded. In this work, the hot deformation behavior of a Ni-Cr-Mo steel was investigated by conducting isothermal compression tests using a Gleeble-3800 thermal simulator with deformation temperatures ranging from 800 °C to 1200 °C, strain rates ranging from 0.01 s−1 to 10 s−1, and deformations of 55%. To analyze the constitutive relation of the Ni-Cr-Mo steel at high temperatures, five machine learning algorithms were employed to predict the flow stress, namely, back-propagation artificial neural network (BP-ANN), Random Committee, Bagging, k-nearest neighbor (k-NN), and a library for support vector machines (libSVM). A comparative study between the experimental and the predicted results was performed. The results show that correlation coefficient (R), root mean square error (RMSE), mean absolute value error (MAE), mean squar... [more]
Performance Degradation Modeling and Continuous Worktime Assessment of Ultrasonic Vibration Systems
Ruoyu Wang, Lei You, Xiaoping Hu.
June 6, 2024 (v1)
Keywords: copula function, degradation model, lifetime prediction, reliability theory, ultrasonic vibration system.
In order to assess the stable operating duration of an ultrasonic vibration system, a reliability-based analysis method for the stability of the ultrasonic vibration system is proposed. Firstly, the failure mechanisms of the ultrasonic vibration system are analyzed, and the resonant frequency and amplitude are selected as two degradation features of the system. Subsequently, accelerated degradation experiments under different force loads were conducted, and the degradation model of the ultrasonic vibration system was established by comparing experimental data with degradation, distribution, and acceleration models. Finally, Copula functions were introduced to connect the two degradation features, resonant frequency, and amplitude, and lifetime curves were plotted under the influence of univariate and bivariate degradation factors. Through the analysis of the lifetime curves, the conclusion is drawn that the decay of amplitude is the primary indicator of system lifetime, and it is predi... [more]
Novel Method on Mixing Degree Quantification of Mine Water Sources: A Case Study
Qizhen Li, Gangwei Fan, Dongsheng Zhang, Wei Yu, Shizhong Zhang, Zhanglei Fan, Yue Fu.
June 6, 2024 (v1)
Keywords: decision tree, discriminant function equation, mine water inrush source, mixing degree of water sources.
After a mine water inrush occurs, it is crucial to quickly identify the source of the water inrush and the key control area, and to formulate accurately efficient water control measures. According to the differences in water chemical characteristics of four aquifers in the Fenyuan coal mine, the concentrations of K+~Na+, Ca2+, Mg2+, Cl−, SO42−, and HCO3− were taken as water source identification indexes. A decision tree classification model based on the C4.5 algorithm was adopted to visualize the chemical characteristics of a single water source and extract rules, and intuitively obtained the discrimination conditions of a single water source with Mg2+, Ca2+, and Cl− as important variables in the decision tree: Mg2+ < 39.585 mg/L, Cl− < 516.338 mg/L and Mg2+ ≥ 39.585 mg/L, Ca2+ < 160.860 mg/L. Factor analysis and Fisher discriminant theory were used to eliminate the redundant ion variables, and the discriminant function equations of the two, three, and four types of mixed wate... [more]
How Would Structural Change in Electricity and Hydrogen End Use Impact Low-Carbon Transition of an Energy System? A Case Study of China
Nuobei Zhang, Zheng Li, Xiaoying Zheng, Pei Liu.
June 6, 2024 (v1)
Keywords: bottom-up model, China, electricity, Hydrogen, scenarios.
Driven by global targets to reduce greenhouse gas emissions, energy systems are expected to undergo fundamental changes. In light of carbon neutrality policies, China is expected to significantly increase the proportion of hydrogen and electricity in its energy system in the future. Nevertheless, the future trajectory remains shrouded in uncertainty. To explore the potential ramifications of varying growth scenarios pertaining to hydrogen and electricity on the energy landscape, this study employs a meticulously designed bottom-up model. Through comprehensive scenario calculations, the research aims to unravel the implications of such expansions and provide a nuanced analysis of their effects on the energy system. Results show that with an increase in electrification rates, cumulative carbon dioxide emissions over a certain planning horizon could be reduced, at the price of increased unit reduction costs. By increasing the share of end-use electricity and hydrogen from 71% to 80% in 20... [more]
Synergetic Mechanism of Multiple Industrial Solid Waste-Based Geopolymer Binder for Soil Stabilization: Optimization Using D-Optimal Mixture Design
Xiaoli Wang, Xiancong Wang, Pingfeng Fu, Bolan Lei, Jinjin Shi, Miao Xu.
June 6, 2024 (v1)
Subject: Optimization
Keywords: D-optimal mixture approach, hydration mechanism, industrial solid waste, soil stabilization.
In order to improve the comprehensive utilization rate of industrial solid waste and the road quality, a novel low-carbon and environmental friendly soil stabilizer is proposed. In this study, steel slag (SS), carbide slag (CS), blast furnace slag (BFS), fly ash (FA), and desulfurized gypsum (DG) were used as raw materials to develop a multiple industrial solid waste-based soil stabilizer (MSWSS). The optimal mix ratio of the raw materials determined by D-optimal design was as follows: 5% SS, 50% CS, 15% BFS, 15% DG, and 15% FA. The 7-day unconfined compressive strength (UCS) of MSWSS-stabilized soil was 1.7 MPa, which was 36% higher than stabilization with ordinary portland cement (OPC) and met the construction requirements of highways. After 7 days of curing, the UCS of MSWSS-stabilized soil was significantly higher than that in the OPC group. X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) analysis indicated that the prominent... [more]
Charging and Discharging Optimization of Vehicle Battery Efficiency for Minimizing Company Expenses Considering Regular User Travel Habits
Jiaoyang Lu, Shan Liu, Jing Zhang, Shuang Han, Xingyuan Zhou, Yongqian Liu.
June 6, 2024 (v1)
Keywords: charging and discharging strategy, enterprise electric vehicles, Monte Carlo simulation, user travel habit.
With the increasing popularity and development of electric vehicles, the demand for electric vehicle charging is also constantly increasing. To meet the diverse charging needs of electric vehicle users and improve the efficiency of charging infrastructure, this study proposes an optimization strategy for electric vehicle charging and discharging. This method considers both the user’s travel mode and the operational efficiency of the charging pile. Firstly, a probability model based on travel spatiotemporal variables and Monte Carlo algorithm were used to simulate the travel trajectory of electric vehicles, providing a data foundation for optimizing the charging and discharging schemes of electric vehicles. Then, with the dual objective of minimizing the operating costs of charging piles and user charging costs, a linear programming model was constructed to optimize the charging and discharging strategies of electric vehicles. Finally, the model was validated using an apartment building... [more]
Optimizing the Salt-Processing Parameters of Achyranthes bidentata and Their Correlation with Anti-Osteoarthritis Effect
Jieqiang Zhu, Lisha Shen, Guofang Shen, Yi Tao.
June 6, 2024 (v1)
Subject: Biosystems
Keywords: Achyranthes bidentata, anti-inflammatory, cyclooxygenase-2, salt-processing.
is always salt-processed before being prescribed for treating osteoarthritis. Yet the salt-processing parameters have not been optimized, and the specific bioactive constituents responsible for the osteoarthritis effect of salt-processed A. bidentata have not been fully elucidated. In this study, a Box−Behnken experimental design was chosen for the optimization of the salt-processing parameters of A. bidentata, including stir-frying time, concentration of brine, and soak time. Meanwhile, HPLC−Q-TOF-MS was utilized to analyze the chemical profiles of various batches of raw and salt-processed A. bidentata. The anti-inflammatory potential of nine batches of both raw and salt-processed A. bidentata was assessed via a cyclooxygenase-2 (COX-2) inhibitory assay. A gray correlation analysis was conducted to correlate the peak areas of the compounds in raw and salt-processed A. bidentata with their COX-2 inhibitory effects. Finally, the optimal salt-processing conditions are as follows: soak ti... [more]
Health Management of Bearings Using Adaptive Parametric VMD and Flying Squirrel Search Algorithms to Optimize SVM
Tianrui Zhang, Lianhong Zhou, Jinyang Li, Huiyuan Niu.
June 6, 2024 (v1)
Keywords: feature dimension reduction, health status assessment, rolling bearing, support vector machine, variational mode decomposition.
Bearing, as one of the core parts of rotating machinery, has a running state which is related to the overall operation of the system. Due to the bearing structure and its complex operating environment, running condition monitoring and fault diagnosis is always a key problem in the field of bearing health management, which is of great significance for bearing maintenance and equipment reliability and safety. In view of the difficulty in parameter selection and poor feature extraction ability of variational mode decomposition (VMD) in existing feature extraction, this paper uses the flying squirrel search algorithm (SSA) to optimize the parametric of decomposition layer k and penalty factor α in VMD, and forms an adaptive VMD signal decomposition method. To solve the problem of high dimensionality and long extraction time of multi-domain fault feature set, kernel principal component analysis (KPCA) is used to reduce feature dimensionality. Then, the processed features are input into the... [more]
Microwave Drying of Sewage Sludge: Process Performance and Energy Consumption
Guangyu Wang, Kai Zhang, Bocheng Huang, Kaihua Zhang, Cong Chao.
June 6, 2024 (v1)
Keywords: drying, energy consumption, kinetics, microwave, sludge.
The microwave drying of sewage sludge is characterized by its speed and safety. A novel method for identifying free and bound water is proposed in this study. Experiments were performed to investigate the process performance and energy consumption in a microwave drying unit. The results indicate that the microwave drying process can be described in three stages, i.e., the preheating stage, constant-rate stage, and decreasing-rate stage. The preheating and constant-rate stages mainly remove free water, while the decreasing-rate stage mainly removes bound water. The Linear model effectively describes the kinetic processes in the constant-rate stage, and the modified Page I model is suitable for describing the decreasing-rate stage. The energy conversion process in microwave drying is explored, revealing that heat efficiency and energy consumption are consistent with microwave power changes. The heat efficiency in the constant-rate drying stage ranges from 60.33% to 71.01%, lower than tha... [more]
Recycling PVC Waste into CO2 Adsorbents: Optimizing Pyrolysis Valorization with Neuro-Fuzzy Models
Emilia A. Jiménez-García, Salvador Pérez-Huertas, Antonio Pérez, Mónica Calero, Gabriel Blázquez.
June 6, 2024 (v1)
Keywords: activated carbon, Carbon Dioxide Capture, neuro-fuzzy model, plastic waste, PVC.
Nowadays, the environmental challenges associated with plastics are becoming increasingly prominent, making the exploitation of alternatives to landfill disposal a pressing concern. Particularly, polyvinyl chloride (PVC), characterized by its high chlorine content, poses a major environmental risk during degradation. Furthermore, PVC recycling and recovery present considerable challenges. This study aims to optimize the PVC pyrolysis valorization process to produce effective adsorbents for removing contaminants from gaseous effluents, especially CO2. For this purpose, PVC waste was pyrolyzed under varied conditions, and the resulting solid fraction was subjected to a series of chemical and physical activations by means of hydroxides (NaOH and KOH) and nitrogen. Characterization of the PVC-based activated carbons was carried out using surface morphology (SEM), N2 adsorption/desorption, elemental analysis, and FTIR, and their capacity to capture CO2 was assessed. Finally, neuro-fuzzy mod... [more]
An Integrated Model for Acid Fracturing without Prepad Considering Wormhole Growth
Yuxin Chen, Haibo Wang, Fengxia Li, Tong Zhou, Ning Li, Yu Bai.
June 6, 2024 (v1)
Keywords: acid fracturing, acid-etched fracture, fracture propagation, mathematical model, wormhole growth.
Acid fracturing is an effective stimulation technology that is widely applied in carbonate reservoirs. An integrated model for acid fracturing without prepad treatment has been established. Compared with the previous models which use prepad for generating hydraulic fractures, this model can simultaneously simulate the fracture propagation and the acid etching of fracture surfaces, as well as the wormhole growth during acid fracturing. The influences of some essential factors have been studied through a series of numerical simulations, and the main conclusions are as follows. First, increasing the injected acid volume can expand the size of the formed hydraulic fractures and extend the propagation distance of the wormhole. Increasing the injected acid volume can also expand the etched width and extend the effective distance of the injected acid. Second, a high injection rate impels more acid to flow into the depth of a fracture before infiltration and reaction, resulting in the augmenta... [more]
Numerical Study of the Buckling Response of Stiffened FG Graphene-Reinforced Multilayer Composite Cylindrical Panels
Zhihong Liu, Francesco Tornabene, Rossana Dimitri, Masoud Babaei.
June 6, 2024 (v1)
Subject: Materials
Keywords: axial buckling, FEM, FSDT, functionally graded material, graphene-reinforced composite multilayer cylindrical panel.
The present research aims at determining the axial buckling load of stiffened multilayer cylindrical shell panels made of functionally graded graphene-reinforced composites (FG-GPL RCs). Rings and stringers are applied as stiffening tools for shell panels, whose elastic properties are determined according to the Halpin−Tsai relations. The virtual work principle and finite element approach are implemented here, according to a first-order shear deformation theory (FSDT) and Lekhnitskii smeared stiffener approach, in order to determine the governing equations of the stability problem. Four different dispersions of nanofillers are assumed in the thickness direction, including the FG-X, FG-A, FG-O, and UD distributions. A large systematic investigation considers the effect of different geometric and material parameters on the buckling loads and mode shapes of the stiffened FG-GPL RC cylindrical shell panel, primarily the dispersion and weight fractions of the nanofiller, the number of rings... [more]
Thermodynamic Modeling of a Solar-Driven Organic Rankine Cycle-Absorption Cooling System for Simultaneous Power and Cooling Production
José C. Jiménez-García, Isaías Moreno-Cruz, Wilfrido Rivera.
June 6, 2024 (v1)
Keywords: absorption system, organic Rankine cycle, parabolic trough, solar cooling and power, solar energy.
Humanity is facing the challenge of reducing its environmental impact. For this reason, many specialists worldwide have been studying the processes of production and efficient use of energy. In this way, developing cleaner and more efficient energy systems is fundamental for sustainable development. The present work analyzed the technical feasibility of a solar-driven power-cooling system operating in a particular location in Mexico. The theoretical system integrates organic Rankine and single-stage absorption cooling cycles. A parabolic trough collector and a storage system integrated the solar system. Its performance was modeled for a typical meteorological year using the SAM software by NREL. The analyzed working fluids for the organic cycle include benzene, cyclohexane, toluene, and R123, while the working fluid of the absorption system is the ammonia-water mixture. The cycle’s first and second-law performances are determined in a wide range of operating conditions. Parameters such... [more]
Process Intensification in Human Pluripotent Stem Cell Expansion with Microcarriers
Misha Alexander Teale, Samuel Lukas Schneider, Dieter Eibl, Regine Eibl.
June 6, 2024 (v1)
Keywords: microcarriers, perfusion, single-use, stirred bioreactor, upstream processing.
Given the demands human induced pluripotent stem cell (hiPSC)-based therapeutics place on manufacturing, process intensification strategies which rapidly ensure the desired cell quality and quantity should be considered. Within the context of antibody and vaccine manufacturing, one-step inoculation has emerged as an effective strategy for intensifying the upstream process. This study therefore evaluated whether this approach could be applied to the expansion of hiPSCs in flasks under static and in microcarrier-operated stirred bioreactors under dynamic conditions. Our findings demonstrated that high density working cell banks containing hiPSCs at concentrations of up to 100 × 106 cells mL−1 in CryoStor® CS10 did not impair cell growth and quality upon thawing. Furthermore, while cell distribution, growth, and viability were comparable to routinely passaged hiPSCs, those subjected to one-step inoculation and expansion on microcarriers under stirred conditions were characterized by impro... [more]
The Treatment of Natural Calcium Materials Using the Supercritical Antisolvent Method for CO2 Capture Applications
Luís C. S. Nobre, Paula Teixeira, Carla I. C. Pinheiro, António M. F. Palavra, Mário J. F. Calvete, Carlos A. Nieto de Castro, Beatriz P. Nobre.
June 6, 2024 (v1)
Subject: Materials
Keywords: Carbon Dioxide Capture, dolomite, marble, micronization, supercritical antisolvent method.
The potential of the supercritical antisolvent micronization (SAS) technique was evaluated for the production of CaO-based particles with a size and a physical structure that could enable high performance for CO2 capture through the calcium looping process. Two sources of calcium derivative compounds were tested, waste marble powder (WMP) and dolomite. The SAS micronization of the derivate calcium acetate was carried out at 60 °C, 200 bar, a 0.5 mL min−1 flow rate of liquid solution, and 20 mg mL−1 concentration of solute, producing, with a yield of more than 70%, needle-like particles. Moreover, since dolomite presents with a mixture of calcium and magnesium carbonates, the influence of the magnesium fraction in the SAS micronization was also assessed. The micronized mixtures with lower magnesium content (higher calcium fraction) presented needle-like particles similar to WMP. On the other hand, for the higher magnesium fractions, the micronized material was similar to magnesium aceta... [more]
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