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Records added in June 2024
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Showing records 201 to 225 of 1043. [First] Page: 5 6 7 8 9 10 11 12 13 Last
Theoretical Simulation of the Resistivity and Fractured−Cavernous Structures of Carbonate Reservoirs
Zhaohui Zhang, Chuqiao Gao, Yongde Gao, Chunzhen Niu, Shenglun Ma
June 21, 2024 (v1)
Keywords: carbonate reservoirs, geologic model, resistivity, theoretical simulation
Recently, theoretical modeling based on rock physics has emerged as a pivotal approach to studying the resistivity of complex fractured−cavernous microstructures. In this work, to study the effects of fractured−cavernous structures on carbonate reservoir resistivity, electrical conductivity models were developed based on the effective medium theory and Ohm’s Law, and theoretical simulations were performed to examine how the porosity and resistivity of the rock matrix, the formation water resistivity, and the parameters of the fractured−cavernous microstructure affect the resistivity of rocks saturated with petroleum or water. Furthermore, the modeling results revealed the specific relationships between these factors in petroleum-saturated and water-saturated rocks. For vuggy reservoirs, a significant negative correlation between throat diameter and resistivity was revealed when variations in the rock matrix and formation water resistivity were negligible. Furthermore, the pore shape—es... [more]
A Human-Centric Design Method for Industrial Centrifugal Pump Based on Digital Twin
Yue Shi, Buyun Sheng, Jiaxing Zhu, Geng Chen, Tianao Zhang, Ruiping Luo
June 21, 2024 (v1)
Keywords: digital twin, industrial centrifugal pump, intelligent linkage design, optimize design, parameterized correlation model
The worldwide demand for customized centrifugal pumps in numerous industries is intensifying steadily, posing significant challenges to the traditional design model characterized by extended design cycles, numerous errors, and elevated development costs. To address these issues, this paper introduces an intelligent collaborative design methodology for industrial centrifugal pumps grounded in digital twin (DT) technology. The methodology aims to handle the diversified types and intricate design requirements of industrial pumps and is specifically tailored to predict pump performance through a detailed multi-physics model. This model encapsulates various physical processes, including fluid dynamics, thermodynamics, and structural mechanics, and incorporates the designer’s professional knowledge and experience to support enhanced decision-making. Furthermore, the application of intelligent parametric models has facilitated the interconnected design of pump components. This advancement has... [more]
Study on the Unsteady Flow Characteristics of a Pump Turbine in Pump Mode
Fei Zhang, Zhenmu Chen, Shuangqian Han, Baoshan Zhu
June 21, 2024 (v1)
Keywords: hump characteristics, pressure fluctuation, pump mode, pump turbine, unsteady flow
Extensive research has been conducted on the performance of pump turbines, particularly focused on understanding the generation mechanism of S-shaped characteristics. However, there has been a lack of research on unsteady flow characteristics in hump characteristics with small guide vane openings. This study focuses on the hump characteristics of a pump turbine in pump mode. The unsteady numerical simulation method is used along with experimental testing to examine the internal flow characteristics and induced pressure fluctuations under pump operating conditions. The results indicate that flow separation occurs in the impeller when the flow rate decreases to the valley operating condition, and recirculation flow occurs near the impeller inlet at the partial flow rate. Moreover, the unstable flow on the positive slope exhibits a low-frequency characteristic of 0.15fn. The pressure fluctuation from the hub to shroud areas of the guide vane region diminishes sequentially. Notably, distin... [more]
Intensification of Hydrogen Production: Pd−Ag Membrane on Tailored Hastelloy-X Filter for Membrane-Assisted Steam Methane Reforming
Serena Agnolin, Luca Di Felice, Alfredo Pacheco Tanaka, Margot Llosa Tanco, Wout J. R. Ververs, Fausto Gallucci
June 21, 2024 (v1)
Keywords: hydrogen separation, metallic supports, methane steam reforming, Pd membranes, surface modification
H2 production via membrane-assisted steam methane reforming (MA-SMR) can ensure higher energy efficiency and lower emissions compared to conventional reforming processes (SMR). Ceramic-supported Pd−Ag membranes have been extensively investigated for membrane-assisted steam methane reforming applications, with outstanding performance. However, costs, sealings for integration in the reactor structure, and resistance to solicitations remain challenging issues. In this work, the surface quality of a low-cost, porous Hastelloy-X filter is improved by asymmetric filling with α-Al2O3 of decreasing size and deposition of γ-Al2O3 as an interdiffusion barrier. On the modified support, a thin Pd−Ag layer was deposited via electroless plating (ELP), resulting in a membrane with H2/N2 selectivity >10,000. The permeation characteristics of the membrane were studied, followed by testing for membrane-assisted methane steam reforming. The results showed the ability of the membrane reactor to overcome t... [more]
Power Generation Prediction for Photovoltaic System of Hose-Drawn Traveler Based on Machine Learning Models
Dan Li, Delan Zhu, Tao Tao, Jiwei Qu
June 21, 2024 (v1)
Keywords: hose-drawn traveler, Machine Learning, prediction model, PV power generation
A photovoltaic (PV)-powered electric motor is used for hose-drawn traveler driving instead of a water turbine to achieve high transmission efficiency. PV power generation (PVPG) is affected by different meteorological conditions, resulting in different power generation of PV panels for a hose-drawn traveler. In the above situation, the hose-drawn traveler may experience deficit power generation. The reasonable determination of the PV panel capacity is crucial. Predicting the PVPG is a prerequisite for the reasonable determination of the PV panel capacity. Therefore, it is essential to develop a method for accurately predicting PVPG. Extreme gradient boosting (XGBoost) is currently an outstanding machine learning model for prediction performance, but its hyperparameters are difficult to set. Thus, the XGBoost model based on particle swarm optimization (PSO-XGBoost) is applied for PV power prediction in this study. The PSO algorithm is introduced to optimize hyperparameters in XGBoost mo... [more]
Optimizing Production Schedules: Balancing Worker Cooperation and Learning Dynamics in Seru Systems
Weiguo Liu, Weizhe Dai, Xuyin Wang
June 21, 2024 (v1)
Keywords: learning effects, seru scheduling, shuffled frog leaping algorithm, worker cooperation
This paper aims to investigate the seru scheduling problem while considering the dual effects of worker cooperation and learning behavior to minimize the makespan and order processing time. Given the complexity of this research problem, an improved shuffled frog leaping algorithm based on a genetic algorithm is proposed. We design a double-layer encoding based on the problem, introduce a single point and uniform crossover operator, and select the crossover method in probability form to complete the evolution of the meme group. To avoid damaging grouping information, the individual encoding structure is transformed into unit form. Finally, numerical experiments were conducted using numerical examples of large and small sizes for verification. The experimental results demonstrate the feasibility of the proposed model and algorithm, as well as the necessity of considering worker dual behavior in the seru scheduling problem.
The Impact of Farm and Industrial Feed Waste on the Safety Parameters of Tenebrio molitor Larvae
Agnė Jankauskienė, Dominykas Aleknavičius, Šarūnas Antanaitis, Sandra Kiseliovienė, Philipp Wedi, Marijona Šumskienė, Ignė Juknienė, Žydrūnė Gaižauskaitė, Aistė Kabašinskienė
June 21, 2024 (v1)
Keywords: biogenic amines, glycoalkaloids, heavy metals, mealworms, pesticides, PHA, plants by-products
The rising global demand for animal-based food has an increasingly detrimental ecological impact, exacerbated by significant food waste (approximately one-third of all food). This research aimed to analyze the possibility of changing the usually balanced feed with sustainable alternatives that remain as a by-product of the production of farms, grain processing, and breweries, thus promoting the sustainability of agriculture. The mealworm larvae were reared on different substrates: (1) agar-agar gels, wheat bran, and brewer’s yeast, (2) carrots, wheat bran, and brewer’s yeast, (3) sprouted potatoes, wheat bran, and brewer’s yeast, and (4) carrots, brewers’ spent grain and brewer’s yeast. For analysis, the frozen larvae were lyophilized and tested for chemical safety in three accredited laboratories. The results have shown that all tested samples had lower levels of pesticides than the detection limit. In scientific literature, we didn’t find studies on polycyclic aromatic hydrocarbons (... [more]
Multi-Objective Optimization of Injection Molding Process Parameters for Moderately Thick Plane Lens Based on PSO-BPNN, OMOPSO, and TOPSIS
Feng Liu, Jianjun Pang, Zhiwei Xu
June 21, 2024 (v1)
Subject: Optimization
Keywords: clamping force, injection molding, moderately thick plane lens, multi-objective optimization, sink marks, warpage
Injection molding (IM) is an ideal technique for the low-cost mass production of moderately thick plane lenses (MTPLs). However, the optical performance of injection molded MTPL is seriously degraded by the warpage and sink marks induced during the molding process with complex historical thermal field changes. Thus, it is essential that the processing parameters utilized in the molding process are properly assigned. And the challenges are further compounded when considering the MTPL molding energy consumption. This paper presents a set of procedures for the optimization of injection molding process parameters, with warpage, sink marks reflecting the optical performance, and clamping force reflecting the molding energy consumption as the optimization objectives. First, the orthogonal experiment was carried out with the Taguchi method, and the S/N response shows that these three objectives cannot reach the optimal values simultaneously. Second, considering the experimental data scale, th... [more]
Hydrodynamics and Mass Transfer in an Airlift Loop Reactor: Comparison between Using Two Kinds of Spargers
Xiao Xu, Yingchun Zhang
June 21, 2024 (v1)
Keywords: airlift loop reactor, gas holdup, jet nozzle, liquid loop velocity, mass transfer, ring orifice distributor
The effects of different spargers on the hydrodynamics and mass transfer of an airlift loop reactor were investigated. The gas holdup, liquid loop velocity, and volumetric mass transfer coefficient of the reactor were tested using a ring orifice distributor and a jet nozzle. The study was conducted in a 6 m high airlift loop reactor at a superficial gas velocity of 0.01~0.04 m/s, and the superficial liquid velocity was maintained at 0.0154 m/s. The results showed that using the jet nozzle provided a higher gas holdup, liquid loop velocity, and mass transfer. When the superficial gas velocity was less than 0.0325 m/s, the liquid loop velocity generated by the jet nozzle was approximately 1.1-fold higher than that generated by the ring orifice distributor, and the disparity in gas holdup between the riser and downcomer enhanced the power of liquid circulation. When the superficial gas velocity was more than 0.0325 m/s, the jet kinetic power dominated the improvement in the liquid loop ve... [more]
Analysis of Essential Oil of Salix babylonica Collected in Vietnam: Phytochemical Components and Antibacterial and Anticancer Activity
Phu Hiep Hoang, Thien Hien Tran, Van Khang Pham
June 21, 2024 (v1)
Subject: Biosystems
Keywords: anti-cancer activity, antibacterial activity, essential oil, Salix babylonica, volatile oil
This study investigated the chemical compositions and inhibitory activities of essential oils (EOs) of Salix babylonica from Vietnam. The gas chromatography−mass spectrometry (GC/MS) system was used to analyze the chemical compositions of Salix babylonica essential oils. A total of twenty-eight and thirty-one compounds were identified in essential oils of the leaves and bark, among which many chemical compositions were identified for the first time in this plant. Salix babylonica essential oils demonstrated antibacterial activities against Gram-negative strains such as Pseudomonas aeruginosa (PA) and Escherichia coli and Gram-positive strains such as Staphylococcus aureus (SA), and demonstrated anti-cancer activities against three cancer cell lines (HepG2, MCF-7 cell, and A549). The evaluation of the ability to inhibit three strains of microorganisms and inhibit the growth of three cancer cell lines was first conducted using essential oils extracted from the plant species S. babylonica... [more]
Evaluation of Supercapacitive Properties of a PPY/PANI Bilayer Electrodeposited onto Carbon-Graphite Electrodes Obtained from Spent Batteries
Rafaela D. Oliveira, Cleverson S. Santos, Bruna M. Hryniewicz, Luís F. Marchesi, Christiana A. Pessoa
June 21, 2024 (v1)
Keywords: carbon graphite, polyaniline, polypyrrole, supercapacitors
Recently, many efforts have been made to reuse spent batteries in response to the growing demand for sustainable materials production. In parallel, supercapacitors have attracted significant attention for their use in addressing some of the limitations of conventional capacitors and batteries. In this context, this paper describes the preparation, characterization, and supercapacitive performance evaluation of carbon-graphite (CG) electrodes obtained from spent zinc−carbon batteries and modified with polypyrrole (PPY) and polyaniline (PANI). The parameters of PPY and PANI electropolymerization were optimized. CG/PPY, CG/PANI, and CG/PPY/PANI electrodes were obtained to compare their electrochemical responses. Cyclic voltammetry (CV), galvanostatic charge−discharge curves (GCDC), and electrochemical impedance spectroscopy (EIS) were used to evaluate the pseudocapacitive properties of the CG/PPY/PANI-modified electrode. The CG/PPY/PANI electrode showed a specific capacitance of 3416 mF c... [more]
A Multi-Output Regression Model for Energy Consumption Prediction Based on Optimized Multi-Kernel Learning: A Case Study of Tin Smelting Process
Zhenglang Wang, Zao Feng, Zhaojun Ma, Jubo Peng
June 21, 2024 (v1)
Subject: Optimization
Keywords: differential evolutionary algorithm, energy consumption prediction, multi-kernel learning, multi-output support vector regression
Energy consumption forecasting plays an important role in energy management, conservation, and optimization in manufacturing companies. Aiming at the tin smelting process with multiple types of energy consumption and a strong coupling with energy consumption, the traditional prediction model cannot be applied to the multi-output problem. Moreover, the data collection frequency of different processes is inconsistent, resulting in few effective data samples and strong nonlinearity. In this paper, we propose a multi-kernel multi-output support vector regression model optimized based on a differential evolutionary algorithm for the prediction of multiple types of energy consumption in tin smelting. Redundant feature variables are eliminated using the distance correlation coefficient method, multi-kernel learning is introduced to improve the multi-output support vector regression model, and a differential evolutionary algorithm is used to optimize the model hyperparameters. The validity and... [more]
An Effective Mercury Ion Adsorbent Based on a Mixed-Matrix Polyvinylidene Fluoride Membrane with Excellent Hydrophilicity and High Mechanical Strength
Ling Cao, Xia Wu, Fajun He, Xianfeng Meng, Wei He, Jing Li, Guidan Zhu, Hehua Zeng, Chuanyi Wang
June 21, 2024 (v1)
Subject: Materials
Keywords: hydrophilicity, mechanical strength, mercury removal, mixed-matrix membrane, polyvinylidene fluoride
Improving the hydrophilicity and mechanical strength of membranes in water treatment applications remains challenging. In this study, modified vermiculite (VT-M) and a hydrophilic polyvinylpyrrolidone (PVP) were introduced into a polyethyleneimine-functionalized polyvinylidene fluoride composite membrane (PVDF/PEI) to prepare a comprehensively modified mixed-matrix PVDF composite membrane adsorbent that exhibited high mechanical strength and excellent hydrophilicity. The modified composite membrane featured good tensile properties, with a maximum tensile strength of 2.093 MPa, which was 2.5 times that of the PVDF/PEI membrane. After 7 s, the water contact angle of the composite membrane decreased to 0°, leading to significantly improved hydrophilicity. The modified composite membrane exhibited excellent adsorption selectivity for mercury ions, with a fitted maximum adsorption capacity of 807 mg/g. In a mixed-metal ion solution, the selectivity of the membrane for Hg(II) ions was 1.2 ×... [more]
Catalysts Based on Nanoscale Iron and Cobalt Immobilized on Polymers for Catalytic Oxidation of Aromatic Hydrocarbons: Synthesis, Physico-Chemical Studies, and Tests of Catalytic Activity
Binara T. Dossumova, Larissa R. Sassykova, Tatyana V. Shakiyeva, Madina S. Ilmuratova, Albina R. Sassykova, Aigul A. Batyrbayeva, Zhanar M. Zhaxibayeva, Ulzhan N. Dzhatkambayeva, Bedelzhan B. Baizhomartov
June 21, 2024 (v1)
Subject: Materials
Keywords: aromatic hydrocarbons, catalysts, chitosan, nanoscale magnetic composites, oxidation, polyethylenimine, polyvinylpyrrolidone
It is known that highly efficient catalysts for the catalytic oxidation of aromatic hydrocarbons can be obtained based on magnetic nanoparticles. The development of nanosized magnetically controlled catalysts for the oxidation of aromatic hydrocarbons with oxygen deserves especially close attention in the territory of the Republic of Kazakhstan, which does not have its own industrial production of oxygen-containing compounds. The aim of this work is to create catalysts based on Fe and Co nanoparticles stabilized with polymers: polyvinylpyrrolidone, chitosan, and polyethylenimine, study them by methods of physico-chemical research, and conduct preliminary tests of catalysts to predict their effectiveness. Magnetic nanoparticles were prepared by the co-precipitation method. Based on the results of the SEM analysis, it was concluded that polymers form composites together with metal nanocrystals. According to preliminary data, the most efficient oxidation of phenol in a non-flowing glass g... [more]
Mechanical Property Comparison of Geopolymer Brick Dried by Electrical and Passive Solar Devices with Phase Change Material (Paraffin Wax)
Jeevan Ashok Kumar, Sattanathan Muthuvel, Rajay Vedaraj Issac Selvaraj, Monsuru Ramoni, Ragavanantham Shanmugam, Ranjitharamasamy Sudhakara Pandian
June 21, 2024 (v1)
Subject: Materials
Keywords: compressive strength, flexural strength, geopolymer brick (GPB), latentheat of fusion, paraffin wax, phase change material (PCM), Renewable and Sustainable Energy, solar dryer, specific heat, tensile strength, thermal conductivity
In geopolymer bricks (GPBs), fly ash content, which is waste from power plants, is converted into bricks by chemical treatment. GPBs can be dried by using appropriate curing methods. Conventionally, electric oven curing is one of the prominent methods. Using a solar dryer instead of an electric oven provides the added advantage of saving high-grade electrical energy. So, in this work, a solar dryer with the phase change material (PCM) paraffin wax and without a PCM is used for curing applications. GPBs gain an added advantage when compared to conventional bricks like cement and sand bricks in terms of strength. A GPB has been taken as a specimen for comparing the compressive strength, tensile split strength, and flexural strength of electrical-energy-based curing and solar-energy-based curing. It has been experimentally observed that solar-energy-based curing with and without a PCM exhibits higher compressive strength, higher tensile split strength, and flexural strength when compared... [more]
Xylose Hydrogenation Promoted by Ru/SiO2 Sol−Gel Catalyst: From Batch to Continuous Operation
Anna Barone, Benedetta Anna De Liso, Henrik Grénman, Kari Eränen, Francesco Taddeo, Claudio Imparato, Antonio Aronne, Vincenzo Russo, Martino Di Serio, Tapio Salmi
June 21, 2024 (v1)
Subject: Materials
Keywords: Catalysis, kinetics, scale-up, xylitol, xylose hydrogenation
Xylose is nowadays converted into xylitol, a popular special chemical sweetener. Xylitol can be used not only in the pharmaceutical and food industries, but also in cosmetics and synthetic resins because of its countless properties. Conventionally, xylitol is produced by slurry reactors operating in batch with dispersed or supported catalysts. Hydrogen is continuously fed to maintain a constant pressure. In this work, the kinetics of the reaction were investigated to find the optimal operating conditions to minimize the by-products obtained. Given the great performances shown by the new Ru/SiO2 sol−gel derived catalyst in glucose hydrogenation, in this work the mentioned catalyst was tested in the hydrogenation of xylose to xylitol both in batch and in continuous production to prove its stability and activity.
Industrial Data-Driven Processing Framework Combining Process Knowledge for Improved Decision-Making—Part 2: Framework Application Considering Activity-Based Costing Concepts
Émilie Thibault, Christian Ledoux, Paul Stuart
June 21, 2024 (v1)
Keywords: activity-based costing, framework, operating regimes, optimization analysis, pulp mill
Operating time series data collected and stored in historian must be managed to extract their full potential. Part 1 of this paper proposed a structured way (a sophisticated approach) to process industrial data; this first part explains in detail the data processing framework used as the basis for the costing analysis present in the second part of this series. The framework considers the analysis scope definition, data management steps, and operating regimes detection and identification. The added value of this proposed framework is demonstrated in Part 2 via the use of cost accounting for operational problem-solving (debottlenecking), i.e., its practicality is validated via its application alongside a cost analysis on the brownstock washing department of a kraft pulp mill. The traditional debottlenecking approach assumes a single operating condition considering that operating regimes allow for a much more sophisticated debottlenecking study of the washing department. With the use of o... [more]
An Energy-Efficient Adaptive Speed-Regulating Method for Pump-Controlled Motor Hydrostatic Drive Powertrains
Huashuai Wang, Yanbin Zhang, Zhangshun An, Rongsheng Liu
June 21, 2024 (v1)
Keywords: adaptive speed control, energy saving, hydrostatic drive, pump-controlled motor
In this paper, a closed hydrostatic drive powertrain (HSDP) composed of an engine, a variable pump, a variable motor, and an energy-efficient adaptive speed-regulating controller (ADC) based on power following is proposed and investigated. The controller can more than guarantee accurate regulation of motor speed through online efficiency estimation based on established loss models of the pump and the motor. It also facilitates the optimal efficiency control of the engine and hydrostatic system through two redundant control freedoms of the HSDP system, making an energy-saving adjustment of the motor speed. At the same time, the controller can prevent engine overload stall and high system pressure by limiting the displacement of the pumps and motors in real time based on the system loads to improve the automatic adaptability of the system to varying loads. Field testing experiments performed by means of a heavy transportation vehicle under different conditions were conducted to verify th... [more]
Novel Betulin-1,2,4-Triazole Derivatives Promote In Vitro Dose-Dependent Anticancer Cytotoxicity
Alexandra Prodea, Andreea Milan, Marius Mioc, Alexandra Mioc, Camelia Oprean, Roxana Racoviceanu, Roxana Negrea-Ghiulai, Gabriel Mardale, Ștefana Avram, Mihaela Balan-Porcărașu, Slavița Rotunjanu, Cristina Trandafirescu, Irina Şoica, Codruța Șoica
June 21, 2024 (v1)
Subject: Biosystems
Keywords: betulin, breast cancer, colorectal cancer, cytotoxicity, melanoma, triazole derivatives
Betulin is a birch bark-derived lupane-type pentacyclic triterpene with a wide spectrum of biological activities. Given their enhanced antiproliferative potential and enhanced pharmacological profile, betulin derivatives are continuously investigated in scientific studies. The objective of the current study was to in vitro assess the antiproliferative properties of novel synthesized 1,2,4-triazole derivatives of diacetyl betulin. The compounds were investigated using three cancer cell lines: A375 (melanoma), MCF-7 (breast cancer), HT-29 (colorectal cancer), and HaCaT (human keratinocytes). Bet-TZ1 had the lowest recorded IC50 values (ranging from 22.41 to 46.92 μM after 48 h of exposure) than its precursor and other tested compounds in every scenario, with the highest cytotoxicity against the A375 cell line. Bet-TZ3 demonstrated comparable cytotoxicity to the previously mentioned compound, with an IC50 of 34.34 μM against A375. Both compounds caused apoptosis in tested cells, by induci... [more]
Development of Chitosan-Based Active Films with Medicinal Plant Extracts for Potential Food Packaging Applications
Kwanele Andy Nxumalo, Olaniyi Amos Fawole, Adeyemi Oladapo Aremu
June 21, 2024 (v1)
Keywords: edible film, food preservation, functional compounds, green packaging, oxidation
In this study, 2% chitosan (Ch) (w/v) was enriched with 1% Lippia javanica, Syzygium cordatum, and Ximenia caffra extract to form Ch+L, Ch+S, and Ch+X, respectively. The control film was the chitosan (Ch) film without plant extracts. The composite films were assessed for their antifungal ability using the agar diffusion method against economically relevant plant pathogens, Botrytis cinerea, and Penicillium expansum. These chitosan films were further evaluated using an X-ray diffractometer and scanning electron microscope, and their physical and mechanical properties were also assessed. The medicinal plants in the chitosan matrix had the highest inhibition zone (10 mm) against P. expansum, while the chitosan-only films had the lowest inhibition zone (3.3 mm). Notably, Ch+S and Ch+X films had the highest inhibition zone (10 mm) against B. cinerea, while chitosan-only films did not avert the spread of B. cinerea. Ch+L films had the highest film thickness (0.189 mm), density (1.62 g·cm3),... [more]
Aerostructural Design Optimization of Wind Turbine Blades
Sagidolla Batay, Aigerim Baidullayeva, Yong Zhao, Dongming Wei, Akerke Baigarina, Erkhan Sarsenov, Yerkin Shabdan
June 21, 2024 (v1)
Keywords: aerostructural optimization, DAFoam, multidisciplinary design optimization, OpenMDAO, TACS
This study presents an aerostructural optimization process for wind turbine blades aimed at enhancing the turbine’s performance. The optimization framework integrates DAFoam as the computational fluid dynamics (CFD) solver, TACS as the finite element method (FEM) solver, Mphys for fluid−structure coupling, and SNOPT as the optimizer within the OpenMDAO framework. The objective is to simultaneously increase the torque generated by the wind turbine while decreasing the mass of the blade, thereby improving its efficiency. The design variables in this optimization process are the blade shape and panel thickness. The aerodynamic objective function is torque, a key performance indicator for wind turbine efficiency. The structural objective function is the blade mass, as reducing mass is essential to minimize material and manufacturing costs. The optimization process utilizes the integrated capabilities of DAFoam, TACS, Mphys, and SNOPT to iteratively evaluate and modify the blade shape and p... [more]
Sizing and Selection of Pressure Relief Valves for High-Pressure Thermal−Hydraulic Systems
Palash K. Bhowmik, Piyush Sabharwall
June 21, 2024 (v1)
Keywords: pressure relief valve, pressure vessel, pressurized system, safety
This study covers the critical concerns related to the sizing, selection, installation, maintenance, and testing of pressure safety valves (PSVs). The aim is to ensure the safety of pressurized systems, hydrostatic transmission systems, and hydraulic plants, including process plants, thermal power plants, and nuclear reactor systems. PSVs are devices that ensure the safety and reliability of pressurized vessels, lines, and systems during overpressure events. The task of selecting which PSV features are of greatest value for a specific purpose is complex—especially in the design of a high-pressure experimental thermal−hydraulic facility for hydrostatic and transient testing of the reactor system—when the systems are in the design and development phases and require qualification and demonstration to prove that they have reached a given level of technological readiness. The present study highlights the required steps for users to follow the associated rules, guidelines, and recommendation... [more]
Coal Molecular Structure Evolution for Methane Adsorption Molecular Mechanism
Wu Li
June 21, 2024 (v1)
Coal is complex as it includes organic matter (macerals) and inorganic matter (minerals) [...]
Electric DQ0 Library Model for Smart Grid Simulation
Víctor Pordomingo, Alejandro Merino, Almudena Rueda
June 21, 2024 (v1)
Keywords: electric modeling and simulation, electric phasor, object oriented modeling, Power2X, smart grid
This paper addresses the pressing need for advanced simulation tools in electric phasor modeling and Smart Grid-Power to X systems. The motivation for this study stems from the critical importance of enhancing the balance between performance and the detailed dynamic representation of the system behavior in the simulations. The identified problem lies in the absence of a comprehensive framework that seamlessly integrates electric phasor DQ0 components into a multi-purpose object-oriented environment. The primary objective of this research is to develop and introduce two simulation libraries, centered around the core component, Electric_DQ0. These libraries aim to establish a robust phasor-based framework, incorporating essential electric components such as sources, loads, branches, power converters, and electric machines. The main goal is to enable dynamic frequency and voltage simulations, particularly focusing on transients in alternators and facilitating Voltage and Frequency Rate of... [more]
A Study of the Physical Characteristics and Defects of Green Coffee Beans That Influence the Sensory Notes Using Machine Learning Models
Blanca Gonzalez-Sanchez, Oscar Sandoval-Gonzalez, Jose de Jesus Agustin Flores-Cuautle, Ofelia Landeta-Escamilla, Otniel Portillo-Rodriguez, Gerardo Aguila-Rodriguez
June 21, 2024 (v1)
Subject: Materials
Keywords: green coffee, Machine Learning, physical properties, sensory notes
This paper presents a detailed analysis of the relation between physical characteristics and defects of green coffee beans and the sensory profile that influence the sensory notes of fragrance, aroma, flavor, and aftertaste of coffee. Machine learning models were used to identify the variables of importance and identify the ways in which these variables affect the sensory note of coffee, to determine which algorithm and its hyperparameters have greater precision in determining the sensory values of coffee such as floral, fruity, herbal, nutty, caramel, chocolate, spicy, resinous, pyrolytic, earthy, fermented, and phenolic. The result indicates the relationship and importance that exist between the physical variables, defects, and size of the green coffee bean, with respect to their respective sensory notes. The data of the proposed system demonstrate that by combining the scores of several experts, a precision can be achieved analogously to that obtained by cupping experts; therefore,... [more]
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