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Showing records 1704 to 1728 of 43292. [First] Page: 1 66 67 68 69 70 71 72 73 74 Last
Efficiency of Supercritical CO2 and Ultrasound-Assisted Extraction Techniques for Isolation of Bioactive Molecules from Sea Buckthorn (Elaeagnus rhamnoides (L.) A. Nelson) Berry Oils and Cakes
Patricija Čulina, Sandra Balbino, Stela Jokić, Verica Dragović-Uzelac, Sandra Pedisić
June 5, 2024 (v1)
Keywords: antioxidant activity, sea buckthorn berry oil and cake, sea buckthorn lipophilic and hydrophilic bioactive molecules, Soxhlet extraction, supercritical CO2 extraction, ultrasound-assisted extraction
This study compared the efficiency of advanced supercritical CO2 extraction (SC-CO2) and conventional Soxhlet extraction (SE) in the isolation of lipophilic bioactive molecules (BAMs) from the oils of different sea buckthorn (SB) berries (Leikora and Ascola). A SB cake, a valuable by-product of oil extraction, was analyzed for phenolic compounds and antioxidant activity (AA). For this purpose, ultrasound-assisted extraction (UAE) with 70% (v/v) ethanol was optimized, and the following optimal UAE conditions were determined: ultrasonic power of 60%, temperature of 50 °C, and extraction time of 20 min. The individual BAMs in the oils and cake extracts were analyzed chromatographically, while the AAs were determined using the ORAC method. The oils extracted with SC-CO2 had a higher content of lipophilic BAMs and a higher AA value than the oils extracted with SE. Palmitic and palmitoleic acids, β-sitosterol, and α-tocopherol dominated the Leikora oil, while a higher content of oleic, linol... [more]
Nano Zero-Valent Iron (nZVI) Encapsulated with ABS (nZVI/(ABS + EC)) for Sustainable Denitrification Performance and Anti-Aggregation
Fanbin Meng, Yuning Yang, Miao Li, Qizhi Zhu, Bing Qin, Chunpeng Yang
June 5, 2024 (v1)
Subject: Materials
Keywords: aggregation, denitrification performance, nano zero-valent iron, permeable reactive barrier, reactivity decrease
Aggregation and sharp reactivity decrease are the key problems of using nano zero-valent iron (nZVI) as a potential reaction medium for a permeable reactive barrier (PRB). In this study, nZVI particles encapsulated within an acrylonitrile−butadiene−styrene (ABS) matrix (nZVI/(ABS + EC)) was fabricated, which for the first time successfully simultaneously solved the above problems via accurately regulating the distribution of nZVI particles in the ABS matrix and regulating the contact between nZVI particles and the contaminated aqueous environment. In addition, the size and number of the pores throughout the ABS matrix were first regulated by ethyl cellulose (EC) for the purpose of controlling the contact between nZVI particles and the nitrate contaminant, affording apparent rate constants (kobs) for denitrification performance in the range of 0.0423 to 0.0820 min−1. The remediation of simulated nitrate-contaminated solution by nZVI/(ABS + EC) was suitably described by the first-order k... [more]
Ultra-Short-Term Power Prediction of Large Offshore Wind Farms Based on Spatiotemporal Adaptation of Wind Turbines
Yuzheng An, Yongjun Zhang, Jianxi Lin, Yang Yi, Wei Fan, Zihan Cai
June 5, 2024 (v1)
Keywords: DCGRU, graph structure learning, Gumbel–softmax, spatiotemporal correlation, ultra-short-term power prediction, wind power
Accurately predicting the active power output of offshore wind power is of great significance for reducing the uncertainty in new power systems. By utilizing the spatiotemporal correlation characteristics among wind turbine unit outputs, this paper embeds the Diffusion Convolutional Neural Network (DCNN) into the Gated Recurrent Unit (GRU) for the feature extraction of spatiotemporal correlations in wind turbine unit outputs. It also combines graph structure learning to propose a sequence-to-sequence model for ultra-short-term power prediction in large offshore wind farms. Firstly, the electrical connection graph within the wind farm is used to preliminarily determine the reference adjacency matrix for the wind turbine units within the farm, injecting prior knowledge of the adjacency matrix into the model. Secondly, a convolutional neural network is utilized to convolve the historical curves of units within the farm along the time dimension, outputting a unit connection probability vec... [more]
Study on the Hydrodynamic Evolution Mechanism and Drift Flow Patterns of Pipeline Gas−Liquid Flow
Qing Yan, Donghui Li, Kefu Wang, Gaoan Zheng
June 5, 2024 (v1)
Keywords: dynamic banded distribution, flow pattern, gas–liquid slug flow, hydrodynamic characteristic, multiphase mixed-transport pipeline, pipe optimization design
The hydrodynamic characteristic of the multiphase mixed-transport pipeline is essential to guarantee safe and sustainable oil−gas transport when extracting offshore oil and gas resources. The gas−liquid two-phase transport phenomena lead to unstable flow, which significantly impacts pipeline deformation and can cause damage to the pipeline system. The formation mechanism of the mixed-transport pipeline slug flow faces significant challenges. This paper studies the formation mechanism of two-phase slug flows in mixed-transport pipelines with multiple inlet structures. A VOF-based gas−liquid slug flow mechanical model with multiple inlets is set up. With the volumetric force source term modifying strategy, the formation mechanism and flow patterns of slug flows are obtained. The research results show that the presented strategy and optimization design method can effectively simulate the formation and evolution trends of gas−liquid slug flows. Due to the convective shock process in the ei... [more]
Application of Corn Straw, an Agro-Waste, to Remove Dyes in an Aqueous Medium, Producing Blue or Red Fibers
Andressa dos Santos, Anne R. Sotiles, Fauze J. Anaissi
June 5, 2024 (v1)
Subject: Environment
Keywords: agro-industrial residue, color stability, corn straw, dyeing artificial, Wastewater
The contaminant dyes that, even at low concentrations, may cause a series of adverse effects in humans and animals, and their removal by adsorption methods using alternative adsorbents as natural fibers, are regarded as a research topic that has become increasingly relevant. In this study, corn straw (CS), an agro-industrial residue, was used to remove dyes. The samples were characterized by ATR-FTIR, SEM-EDS, zeta potential, diffuse spectra, and colorimetry, before and after dye removal. The analyses allowed us to differentiate the morphology of CS after the treatment’s fiber on the adsorbent surface. The zeta potential showed a negative surface charge, but the acidic or alkaline treatment affected the surface charge of the sample, influencing the adsorption of cationic or anionic dyes. Adsorption data presented an increased removal when alkaline treatment was applied for the methylene blue (MB; qmax = 16.7 mg g−1), and the acid treatment was more effective for the Congo red (CR; qmax... [more]
Physical Modeling of a Water Hydraulic Proportional Cartridge Valve for a Digital Twin in a Hydraulic Press Machine
Oscar Bautista Gonzalez, Daniel Rönnow
June 5, 2024 (v1)
Keywords: hydraulic press, proportional cartridge valve, steel industry, system identification, water hydraulics, white box modeling
Digital twins are an emerging technology that can be harnessed for the digitalization of the industry. Steel industry systems contain a large number of electro-hydraulic components as proportional valves. An input−output model for a water proportional cartridge valve was derived from physical modeling based on fluid mechanics, dynamics, and electrical principles. The valve is a two-stage valve with two two/two-way water proportional valves as the pilot stage and a marginally stable poppet-type cartridge valve as the main valve. To our knowledge, this is the first time that an input−output model was derived for a two-stage proportional cartridge valve with a marginally stable main valve. The orifice equation, which is based on Bernoulli principles, was approximated by a polynomial, which made the parameter estimation easier and modeling possible without measuring the pressure of the varying control volume, in contrast with previous studies of similar types of valves situated in the pilo... [more]
Experimental Investigation on Oxy-Hydrogen Gas Flame Injecting Coal Powder Gasification and Combustion
Jie Cui, Honglei Zhao, Youning Xu, Shuo Yang, Honggang Pan, Wenke Xiao, Yudong Fu, Zhijia Xue
June 5, 2024 (v1)
Keywords: burning performance, coal powder with different concentrations, hydrogen ignition, Oxy-hydrogen Gas, stable combustion
Hydrogen energy is an important carrier for energy terminals to achieve green and low-carbon transformation. Hydrogen, as a carbon-free fuel, has great research and development value in the field of thermal power generation. This article proposes a solution for the stable combustion of coal powder using Oxy-hydrogen Gas ignition technology. An Oxy-hydrogen Gas flame injection coal powder combustion testing device was constructed to experimentally study the temperature distribution in the combustion chamber under Oxy-hydrogen Gas ignition technology, with primary air coal powder concentrations of 0.27, 0.32, and 0.36 (kg coal powder/kg air), as well as the concentration changes of volatile CO emissions during the ignition of coal powder using both Oxy-hydrogen Gas and CH4 flames. The sensitivity of the NO generation during coal gasification combustion under the Oxy-hydrogen Gas ignition was simulated and analyzed. The results show that at a coal powder concentration of 0.32 (kg coal/kg... [more]
Anomaly Identification for Photovoltaic Power Stations Using a Dual Classification System and Gramian Angular Field Visualization
Zihan Wang, Qiushi Cui, Zhuowei Gong, Lixian Shi, Jie Gao, Jiayong Zhong
June 5, 2024 (v1)
Keywords: anomaly detection, attention matrix, CNN, Gramian angular field, PV power station, time series data
With the increasing scale of photovoltaic (PV) power stations, timely anomaly detection through analyzing the PV output power curve is crucial. However, overlooking the impact of external factors on the expected power output would lead to inaccurate identification of PV station anomalies. This study focuses on the discrepancy between measured and expected PV power generation values, using a dual classification system. The system leverages two-dimensional Gramian angular field (GAF) data and curve features extracted from one-dimensional time series, along with attention weights from a CNN network. This approach effectively classifies anomalies, including normal operation, aging pollution, and arc faults, achieving an overall classification accuracy of 95.83%.
Non-Thermal Plasma Technology for Further Purification of Flue Gas in the Resource Utilization Process of Waste Mercury Catalyst: A Case Study in Xinjiang, China
Qinzhong Feng, Kaiyue Wang, Shitong Yang, Jianbo Guo, Jun Chen, Tongzhe Wang, Liyuan Liu, Yang Chen
June 5, 2024 (v1)
Subject: Environment
Keywords: environmentally friendly, mercury-containing flue gas, non-thermal plasma technology, resource utilization process, waste mercury catalyst
This study aims to advance the recycling of mercury-containing waste and promote sustainable development within the polyvinyl chloride (PVC) industry. Our innovative system integrates pre-treatment technology (spraying potassium permanganate and demisting and dust removal) with efficient non-thermal plasma oxidation, resulting in excellent treatment efficiency, low cost, and simple operation. With a processing capacity of 3000 m3/h, the concentration of mercury emissions in flue gas can achieve the target of <0.01 mg/m3, boasting a removal efficiency exceeding 98%, which satisfies the standard “Emission standard of air pollutants for industrial kiln and furnace” (GB 9078-1996). Our results can provide technical support for the comprehensive purification of mercury-containing flue gas during the resource recovery process from mercury-containing waste. The application of our system can contribute to reducing mercury emissions in the PVC industry, lowering occupational exposure risks f... [more]
Phenolic Compounds, Fatty Acid Composition, and Antioxidant Activities of Some Flaxseed (Linum usitatissimum L.) Varieties: A Comprehensive Analysis
Mehmet Zeki Koçak
June 5, 2024 (v1)
Keywords: antioxidant activity, linseed, Linum usitatissimum, phenolic ingredient, α-linolenic acid
Flaxseed, also known as flax or linseed (Linum usitatissimum L.), is one of the oldest crops. It is used for oil and fiber production. The species displays a broad range of biological activities due to its chemical compounds. It has a widespread geographical distribution, and a large number of its varieties have been evaluated for their biological efficacy and nutritional value. This study investigates fifteen varieties of the species, some of which are examined for the first time. In this regard, a series of chemical composition analyses and antioxidant assays were carried out. Accordingly, total phenolic content ranged between 613.6 (Michael) and 3164.6 (Atalanta) mg GAE/g, whilst total flavonoid content varied from 176.25 (BonnyDoon) to 689.20 (Mcduff) mg QE/g. Regarding the radical scavenging assays, the values obtained were significantly higher than those of the standard antioxidant (ascorbic acid). Furthermore, the extracts exhibited chelating activity for ferrous ions and a cupr... [more]
On Designing a New Control Chart Using the Generalized Conway−Maxwell−Poisson Distribution to Monitor Count Data
Fakhar Mustafa, Rehan Ahmad Khan Sherwani, Muhammad Ali Raza, Jumanah Ahmed Darwish
June 5, 2024 (v1)
Keywords: control chart, count data, longer tail, over-dispersion, under-dispersion, zero-inflation
Many researchers employed Poisson distribution-based control charts to monitor count data. Nevertheless, these charts can handle count data that deviate from the Poisson assumption of equal mean and variance. This paper suggests a new control chart (CC) that uses the generalized Conway−Maxwell−Poisson (GCOMP) distribution, which can deal with count data that have different levels of dispersion and zero-inflation (ZI). The proposed chart is designed considering the total number of counts. The main advantage of this study is that it pays attention to the tails of the count data when monitoring the process. The performance is measured by the average run length using L control limits at different sample sizes and parametric settings. The findings demonstrate that, for count data with varying tail behaviors, the proposed chart performs better compared to existing CCs. ZI count data can also be monitored with the proposed chart. The proposed chart can be applied in a variety of fields, as ve... [more]
Differential Analysis of Pomelo Peel Fermentation by Cordyceps militaris Based on Untargeted Metabolomics
Yannan Xiang, Siyi Tian, Xinyu Luo, Chenggang Cai, Yaowen Du, Hailong Yang, Haiyan Gao
June 5, 2024 (v1)
Keywords: Cordyceps militaris, Fermentation, multivariate statistical analysis, pomelo peel, untargeted metabolomics
The content of differentially abundant metabolites in the fermentation broth of grapefruit peels fermented by Cordyceps militaris at different fermentation times was analyzed via LC−MS/MS. Small molecule metabolites and differential metabolic pathways were analyzed via multivariate analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. A total of 423 metabolites were identified at 0, 2, 6, and 10 days after fermentation. Among them, 169 metabolites showed differential abundance, with significant differences observed between the fermentation liquids of every two experimental groups, and the metabolite composition in the fermentation liquid changed over the fermentation time. In summary, the upregulation and downregulation of metabolites in cancer metabolic pathways collectively promote the remodeling of cancer cell metabolism, facilitating increased glycolysis, alterations in TCA cycle flux, and enhanced biosynthesis of the macromolecules required for rapid proliferatio... [more]
Numerical Study of Cavitation Characteristics through Butterfly Valve under Different Regulation Conditions
Guang Zhang, Runhua Hu, Dapeng Yin, Desheng Chen, Haolin Zhou, Zhe Lin
June 5, 2024 (v1)
Keywords: butterfly valve, cavitation, cavitation coefficient, flow coefficient, vapor volume fraction
Butterfly valves are widely used in the pipeline transportation industry due to their safety and reliability, as well as their low manufacturing and operation costs. Cavitation is a common phenomenon in the butterfly valve that can lead to serious damage to a valve’s components. Therefore, it is important to investigate the generation and evolution of cavitation in butterfly valves. In this study, LES and the Zwart model were used as the turbulence and cavitation models, respectively, to simulate cavitation through a butterfly valve. The influence of the valve opening degree and inlet flow velocity on dynamic cavitation through the butterfly valve were studied. Furthermore, the cavitated flow field was examined, along with the performance coefficients of the butterfly valve. With the increase in the incoming flow velocity, the high-speed jet zone over a large-range and low-pressure zone appeared inside the downstream of butterfly valve, which affected its stability and the cavitation g... [more]
The Optimization of Nickel-Rich Cathode-Material Production on a Pilot Plant Scale
Agus Purwanto, Muhammad Nur Ikhsanudin, Putri Putih Puspa Asri, Afifah Salma Giasari, Miftakhul Hakam, Cornelius Satria Yudha, Hendri Widiyandari, Endah Retno Dyartanti, Arif Jumari, Adrian Nur
June 5, 2024 (v1)
Subject: Materials
Keywords: cathode, electric vehicle, Li-ion battery, NMC-811, pilot scale
Lithium-ion batteries (LIBs) remain the cornerstone of EV technology due to their exceptional energy density. The selection of cathode materials is a decisive factor in LIB technology, profoundly influencing performance, energy density, and lifespan. Among these materials, nickel-rich NCM cathodes have gained significant attention due to their high specific capacity and cost-effectiveness, making them a preferred choice for EV energy storage. However, the transition from the laboratory-scale to industrial-scale production of NMC-811 cathode material presents challenges, particularly in optimizing the oxidation process of Ni2+ ions. This paper addresses the challenges of transitioning NMC-811 cathode material production from a lab scale to a pilot scale, with its high nickel content requiring specialized oxidation processes. The important point emphasized in this transition process is how to produce cathode materials on a pilot scale, but show results equivalent to the laboratory scale.... [more]
Exploring Safety of Machineries and Training: An Overview of Current Literature Applied to Manufacturing Environments
Maria Elena Del Giudice, Mahnaz Sharafkhani, Mario Di Nardo, Teresa Murino, Maria Chiara Leva
June 5, 2024 (v1)
Subject: Environment
Keywords: review, safety, safety of machinery, systematic literature review
A machine is described as an assembly that has a drive system installed or is planned to have a drive system installed and that is constituted of linked elements or components, at least one of which moves, that are connected for a particular application (ISO12100). Different types of risks are present in machines, and exposure to them can cause harm or even death. When risk has been adequately reduced, machinery safety considers a machine’s ability to complete its intended duty throughout its life cycle. A literature review was carried out using “safety of machinery” as a keyword, which produced an analysis of 29 papers published from 2008 to 2024. The papers were examined through bibliometric analysis of the year of publication, country, citation statistics, and study of the keywords. These studies were classified into accident analysis papers, papers focused on the normative, papers that addressed risk assessment tools, and papers that conducted quantitative research. In addition, a... [more]
Generation Mechanism of Hydroxyl Free Radicals in Micro−Nanobubbles Water and Its Prospect in Drinking Water
Tianzhi Wang, Ci Yang, Peizhe Sun, Mingna Wang, Fawei Lin, Manuel Fiallos, Soon-Thiam Khu
June 5, 2024 (v1)
Keywords: biofilm, drinking water security, engineering application, hydroxyl radical, micro–nanobubbles, pollutants
Micro−nanobubbles (MNBs) can generate ·OH in situ, which provides a new idea for the safe and efficient removal of pollutants in water supply systems. However, due to the difficulty in obtaining stable MNBs, the generation efficiency of ·OH is low, and the removal efficiency of pollutants cannot be guaranteed. This paper reviews the application research of MNB technology in water security from three aspects: the generation process of MNBs in water, the generation rule of ·OH during MNB collapse, and the control mechanisms of MNBs on pollutants and biofilms. We found that MNB generation methods are divided into chemical and mechanical (about 10 kinds) categories, and the instability of the bubble size restricts the application of MNB technology. The generation of ·OH by MNBs is affected by the pH, gas source, bubble size, temperature, and external stimulation. And the pH and external stimulus have more influence on ·OH generation in situ than the other factors. Adjusting the pH to alkal... [more]
Time-Specific Thresholds for Batch Process Monitoring: A Study Based on Two-Dimensional Conditional Variational Auto-Encoder
Jinlin Zhu, Zhong Liu, Xuyang Lou, Furong Gao, Zheng Zhang
June 5, 2024 (v1)
Keywords: batch process monitoring, conditional dynamic variational auto-encoder, deep reconstruction-based contribution, fault detection and diagnosis
This paper studies the use of varying threshold in the statistical process control (SPC) of batch processes. The motivation is driven by how when multiple phases are implicated in each repetition, the distributions of the features behind vary with phases or even the time; thus, it is inconsistent to uniformly bound them by an invariant threshold. In this paper, we paved a new path for learning and monitoring batch processes based on an efficient framework integrating a model termed conditional dynamic variational auto-encoder (CDVAE). Phase indicators are first used to split the data and are then separated, serving as an extra input for the model in order to alleviate the learning complexity. Dissimilar to the routine using features across all timescales, only features relevant to local timestamps are aggregated for threshold calculation, producing a varying threshold that is more specific for the process variations occurring among the timeline. Leveraged upon this idea, a fault detect... [more]
Energy Efficiency in Heat Pumps and Solar Collectors: Case of Slovakia
Stefan Kuzevic, Marcela Tausova, Katarina Culkova, Lucia Domaracka, Danylo Shyp
June 5, 2024 (v1)
Subject: Energy Policy
Keywords: consumption of resources, green economy, process of energy production, Renewable and Sustainable Energy, renewable resources
Sustainable energy presently represents the energy of the future, which should be based on the application respecting the importance of energy priorities, increasing regional self-sufficiency, regional control of energy, and regulation of resource use. In the area of energy supply, the use of RES has been increasingly popular, mainly due to the instability in the energy market and the political situation worldwide. Paper’s ambition is to evaluate the efficiency of the selected RES use in the specific conditions of Slovakia, with the aim to achieve the EU targets. This is important due to the increasing use of RES in Slovakia. The objective of this paper is achieved through an analysis of the energy profit of the RES system, comparing the costs of the proposed solutions. The evaluation is carried out by calculating the energy and economic efficiency of three possible buildings used in the research. Using the data obtained, the results show the most suitable alternative for each building... [more]
Calculation Method of Support Load Zoning and Mechanism of Mine Pressure Behavior in Upward Mining Face across Half of the Goaf along the Panel Direction
Yujiang Zhang, Fudong Ma, Guorui Feng, Shuai Zhang, Jie Li, Qian Wang, Xianfeng Zhang, Shule Li, Yexing Chen
June 5, 2024 (v1)
Keywords: across half of goaf along panel direction, mine pressure behavior, support load, upward mining, zoning calculation method
The 1515 mining face in Yongming Coal Mine was upward mined across half of the goaf along the panel direction. In this paper, the methods of field measurement, theoretical analysis, and numerical simulation were used to study the overlying rock fracture structure, support load characteristics, and the mechanism of mine pressure behavior across half of the goaf. The results indicate that the support load of the 1515 upward mining face across half of the goaf along the panel direction exhibits distinct zoning characteristics. The maximum support load is 1.37 times the minimum support load. The development height of the roof separation in the up-mining area is 1.74 times that in the entity coal area, at 9.1 m and 5.22 m respectively. The height of separation and hanging roof length increase and decrease, respectively, along the initial rock fracture area, tensile fracture area, structural fracture area, and compacted fracture area. Based on the definition of the variation coefficient “m”... [more]
Analysis of Factors Influencing the Stability of Submarine Hydrate-Bearing Slopes during Depressurization Production
Ting Sun, Zhiliang Wen, Jin Yang, Kaidie Yang, Zengcheng Han, Jiayuan He
June 5, 2024 (v1)
Keywords: coupled thermal–hydraulic–mechanical–chemical mathematical model, depressurization mining, natural gas hydrate, orthogonal experimental design, strength discount method, submarine slope stability
Natural gas hydrate reservoirs, with shallow burial, poor cementation, and low strength, are prone to submarine landslides triggered by hydrate decomposition during extraction. Prior studies have inadequately considered factors such as the dynamic decomposition of hydrates during depressurization, and its impacts on the reservoir’s geomechanical properties. In this paper, a coupled thermal−hydraulic−mechanical−chemical mathematical model of hydrate decomposition is proposed, and the dynamic geomechanical response and the effect of hydrate decomposition on seafloor settlement and slope destabilization during the process of depressurization mining are analyzed by combining the strength discount method with the example of a hydrate-bearing seafloor slope in the Shenhu area. Furthermore, the study employs an orthogonal experimental design along with range and variance analysis to gauge the impact of critical factors (degree of hydrate decomposition, seawater depth, hydrate reservoir burial... [more]
Features of Processes for Preparation and Performance of Foamed Lightweight Soil with Steel Slag Micronized Powder and Granulated Blast Furnace Slag
Hao Liu, Jixin Li, Qiqing He, Zhixiong Yang, Longfan Peng, Yuan Li, Gaoke Zhang
June 5, 2024 (v1)
Subject: Materials
Keywords: alkali excitation, foamed lightweight soil, granulated blast furnace slag, soil stability, steel slag micronized powder
Steel slag micronized powder, granulated blast furnace slag, and cement were used as cementitious materials to prepare a foamed lightweight soil for roadbed filling to reduce the settlement and additional stress of the foundation and to solve the environmental problems caused by the storage of large amounts of steel slag. However, the instability of steel slag and the multi-angular nature of its surface limit the resource utilization of steel slag. Currently, concrete technology is unable to achieve a large amount of steel slag. Therefore, it is necessary to deeply explore the influence of steel slag content and the specific surface area of steel slag on the working performance, compressive strength, durability, and micro-mechanism of foam light soil. Through the modification of steel slag and the improvement of the production process, the preparation of foam light soil with a large amount of steel slag can be realized. In this study, the foamed lightweight soil with 1.0 Mpa was prepar... [more]
Soft Sensor Modeling Method Considering Higher-Order Moments of Prediction Residuals
Fangyuan Ma, Cheng Ji, Jingde Wang, Wei Sun, Ahmet Palazoglu
June 5, 2024 (v1)
Keywords: industrial cracking furnace, kurtosis, normal distribution, skewness
Traditional data-driven soft sensor methods can be regarded as an optimization process to minimize the predicted error. When applying the mean squared error as the objective function, the model tends to be trained to minimize the global errors of overall data samples. However, there are deviations in data from practical operation, in which the model performance in the estimation of the local variations in the target parameter worsens. This work presents a solution to this challenge by considering higher-order moments of prediction residuals, which enables the evaluation of deviations of the residual distribution from the normal distribution. By embedding constraints on the distribution of residuals into the objective function, the model tends to converge to the state where both stationary and deviation data can be accurately predicted. Data from the Tennessee Eastman process and an industrial cracking furnace are considered to validate the performance of the proposed modeling method.
Performance of Mg/Al and Zn/Al Hydroxide Double Lamellar-Bentonite for Removal of Anionic Azo Dye from Aqueous Solution
Mohammed Mustapha Bouhent, Kahina Bentaleb, Abdulrahman Al-Ameri, Ulrich Maschke
June 5, 2024 (v1)
Subject: Environment
Keywords: Adsorption, azoic orange II dye, bentonite, layered double hydroxides, wastewater treatment
This paper presents the preparation and characterization of bentonite coated with hydroxide double lamellar Mg/Al-bentonite and Zn/Al-bentonite as a potential adsorbent material. The coating process involved co-precipitation of mixed metal nitrate solution (Mg-Al) or (Zn-Al), followed by immersion of bentonite (B-Na+) dispersion. The structures and morphologies of the coated bentonites were characterized using XRD, FTIR, BET, and SEM analysis. The results of the BET analysis indicate that Mg/Al-bentonite and Zn/Al-bentonite have larger surface areas and pore volumes compared to bentonite alone. Specifically, the surface area of Mg/Al-bentonite is 209.25 m2/g with a pore volume of 0.423 cm3/g, while Zn/Al-bentonite has a surface area of 175.95 m2/g and a pore volume of 0.313 cm3/g. In contrast, the surface area and pore volume of bentonite alone are 110.43 m2/g and 0.132 cm3/g, respectively. The Mg/Al-bentonite reaches 85% uptake within 3 h (equivalent to 724.20 mg/g at 25 °C and pH 7),... [more]
Research on the Control and Performance of Integrated Self-Assembled Micro-Scale Structure of NC-Coated CL-20
Haoran Wang, Yibo Hao, Lei Su, Jingyu Wang, Xiaodong Li, Xiaofeng Shi
June 5, 2024 (v1)
Subject: Materials
Keywords: CL-20, energetic materials, NC, self-assembled, spray-drying method, thermal sensitivity
A novel self-assembly approach was employed to produce micro-spherical composite energetic material (EM) comprising 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane/nitrocellulose (CL-20/NC) via the spray-drying method, with precise control over parameters such as droplet diameter, ambient temperature, and nozzle injection rate. In this method, NC was utilized as a coating for CL-20 to imbue it with distinct spatial characteristics, thereby mitigating its high sensitivity. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses were conducted to investigate the morphology of the CL-20/NC micro-spheres. Additionally, differential scanning calorimetry (DSC) was employed to study the thermal decomposition kinetics of both CL-20 and CL-20/NC. XRD findings revealed that the crystal structure of CL-20/NC micro-spheres prepared using acetone as the solvent remained unchanged, albeit with noticeable attenuation in diffraction peaks. DSC analysis indicated an increase... [more]
Mathematical Model of Graphene Yield in Ultrasonic Preparation
Jinquan Yi, Baoshan Gu, Chengling Kan, Xudong Lv, Zhifeng Wang, Peiyan Yang, Haoqi Zhao
June 5, 2024 (v1)
Keywords: graphene yield, optimal process parameters, regression model, ultrasonic
Based on the Box−Behnken design (BBD) methodology, an experimental study of the preparation of graphene using ultrasonication was conducted. The yield of graphene served as the response variable, with ultrasonication process time, ultrasonic power, the graphite initial weight, and their interactive effects acting as the independent variables influencing the yield. A multivariate nonlinear regression model was established to describe the ultrasonic production of graphene. Verification of the experiments suggests that the developed multivariate nonlinear regression model is highly significant and provides a good fit, enabling an effective prediction of the graphene yield. The yield of graphene was found to increase with higher ultrasonic power but decrease with longer ultrasonication times and the initial weight of the graphite. The optimal process parameters according to the regression model were determined to be 30 min of ultrasonication time, an ultrasonic power of 1500 W, and a graph... [more]
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