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Showing records 51 to 75 of 4403. [First] Page: 1 2 3 4 5 6 7 Last
Evolution of Rheological and Microscopic Properties of Asphalt Binders under Fuel Corrosion
Ming Lv, Hongjun Li, Shiping Zhang, Wenchang Liu, Hongchao Zhang, Hongwei Lin, Mutian Sun
June 10, 2024 (v1)
Subject: Materials
Keywords: asphalt binder, fuel corrosion, microscopic morphology, physical component, rheological
Vehicle fuel leaks can adversely affect the performance of asphalt pavements. To study the mechanisms of fuel corrosion damage in asphalt, four asphalt binders were selected in this study, and the evolution of their rheological and microscopic properties was investigated. Fuel corrosion caused continuous mass loss in asphalt binders. Base asphalt lost more than 50% of its mass after 24 h of fuel corrosion, while modified asphalts had better resistance. According to dynamic shear rheometer tests and multiple stress creep recovery tests, modifiers improved the high-temperature rheological properties of these asphalt binders. As the degree of fuel corrosion deepened, the indexes characterizing the high-temperature performance deteriorated. Rubber-modified asphalt showed the best resistance to high-temperature deformation, while the performance of LDPE-modified asphalt was more stable. In contrast, fuel corrosion improved the resistance of asphalt binders to low-temperature cracking to som... [more]
Use of Thermodynamically Consistent Phase Equilibrium Data to Obtain a Generalized Padé-Type Model for the Henry’s Constants of Gases in Ionic Liquids
Claudio A. Faúndez, Luis A. Forero, José O. Valderrama
June 10, 2024 (v1)
Subject: Materials
Keywords: Henry’s constant, ionic liquids, Padé approximants, solubility, thermodynamic consistency
A generalized Padé-type expression is proposed for Henry’s constant of gases in ionic liquids. The constants are determined using an equation of state, and generalized expressions for the Henry’s constants of the gases in the ionic liquids are proposed. The solute gases included in the study were oxygen, hydrogen, and carbon monoxide in three solvent ionic liquids ([MDEA][Cl], [Bmim][PF6], and [Hmim][TF2N]). The Valderrama−Patel−Teja equation of state with the mixing rules of Kwak and Mansoori are employed to correlate the solubility data, to examine the thermodynamic consistency of the experimental data, and to determine the fugacity (fi) for each concentration (xi) of the solute gas in the liquid phase. From these data, the fugacity coefficients (fiL/xi) are determined to obtain Henry´s constant as Hi = lim(fiL/xi) when xi→0. The calculated Henry’s constants are correlated in terms of the temperature and acentric factor of the gases to finally obtain a generalized expression for Henr... [more]
Experimental Research on Deep Silicon Removal in Spent SCR Catalysts
Weihong Wu, Li Wang, You Zhang, Zhesheng Hua, Hao Song, Shaojun Liu, Sihui Song, Dingzhen Wang, Xiang Gao
June 10, 2024 (v1)
Subject: Materials
Keywords: alkali leaching, hydrofluoric acid, silicon removal, spent SCR catalyst, TiO2
In this research, hydrofluoric acid (HF) was used as a leaching agent to remove silicon impurities from titanium dioxide powder regenerated from a spent SCR catalyst. Further, the effects of HF concentration, liquid−solid ratio, leaching temperature, and leaching time on the leaching rate of regenerated titanium dioxide powder were investigated. The results revealed that the leaching rate of silicon in alkali-leached samples could reach 99.47% under the following conditions: 4% HF concentration, a leaching temperature of 50 °C, and a liquid−solid ratio of 5:1. When compared under identical experimental conditions, the silicon leaching rate in the alkali leached sample using HF surpassed that of the spent SCR catalyst. This suggests that high-temperature alkali leaching led to the degradation of the catalyst and the glass fiber within it, rendering this process more favorable for silicon leaching.
Study on Drying of Seaweeds and Importance of Glass Transition and Stabilization
Ignat Tolstorebrov, Wijitha Senadeera, Trygve Magne Eikevik, Michael Bantle, Maren Sæther, Inna Petrova
June 7, 2024 (v1)
Subject: Materials
Keywords: brown seaweeds, low temperature drying, sorption isotherms, thermal transitions
In this study, the thermal transition of seaweed Saccharina latissima (raw and blanched) during drying and quality stabilization was considered in view of understanding physico-chemical changes, color changes, sorption changes and thermal property changes with respect to drying kinetics. The variations in the effective moisture diffusivity coefficient with shrinkage changes and temperature lie between 1.0 and 5.0 × 10−10 m2 s−1 (raw) and 0.5 and 3.6 × 10−10 m2 s−1 (blanched), respectively. Noticeable physical and chemical changes were observed during longer drying times, especially in the case of blanched seaweeds. At the temperature of 38.0 °C, a more yellow-colored product was obtained from raw form input materials. The blanched seaweeds accumulated moisture in a linear manner with an increase in the relative humidity of the drying air in the range of 20.0~80.0%, which resulted in high level of hysteresis between the sorption and desorption behavior. Shrinkage changes during the dryi... [more]
Investigation of Heat Transfer Performance in Deionized Water−Ethylene Glycol Binary Mixtures during Nucleate Pool Boiling
Chen Xu, Jie Ren, Zuoqin Qian, Lumei Zhao
June 7, 2024 (v1)
Subject: Materials
Keywords: heat transfer coefficient, non-azeotropic mixtures, temperature glide, thermophysical properties
Pool boiling heat transfer is recognized as an exceptionally effective method, widely applied across various industries. The adoption of non-azeotropic binary mixtures aligns with the environmental objectives of modern industrial development and enhances the coefficient of performance (COP) in numerous systems. Therefore, investigating the boiling heat transfer characteristics of these mixtures is crucial to improving their industrial usability. In this study, mixtures of ethylene glycol and deionized water (EG/DW) in varying concentrations were chosen as the working fluids. A comprehensive experimental setup was developed, followed by a series of experiments to assess their pool boiling performance. Simultaneously, the thermophysical parameters of these mixtures underwent detailed examination and analysis. The research revealed that the concentration of EG in the mixture markedly affects its thermal properties and temperature glide, both of which are crucial in influencing the heat tr... [more]
Advances in Supported Nanoparticle Catalysts
Sónia Alexandra Correia Carabineiro
June 7, 2024 (v1)
Subject: Materials
In catalysis, the design and application of supported nanoparticle catalysts is a cornerstone for addressing contemporary challenges in environmental remediation, sustainable synthesis, and analytical methodologies [...]
The Development of Anti-Salt Fluid Loss Additive for Cement-Metakaolin Slurry with Semi-Saturated/Saturated Saline Water: The Application of Maleic Anhydride
Xiaojiang Li, Hui Yin, Shiming Zhou, Huajie Liu, Junfeng Zhao, Hongxu Zhang
June 7, 2024 (v1)
Subject: Materials
Keywords: characterization analysis, fluid loss additive, molecular structure design, salt resistance
Conventional fluid loss additives have difficultly controlling the water loss of cement−metakaolin slurry with semi-saturated brine cement slurry and limiting it to less than 50 mL (30 min)−1. This paper describes the development of an anti-salt fluid loss additive for metakaolin−cement systems. This study adopted the aqueous solution polymerization method; selected four kinds of monomers, namely 2-Acrylamido-2-methylpropane sulfonic acid (AMPS), N,N-Dimethylacrylamide (DMAA), acrylamide (AM), and methyl acrylate (MA); and performed a single-factor experiment on the proportion of monomer, reaction temperature, initiator dosage, and developed fluid loss additive, which has a high salt tolerance and temperature tolerance. This fluid loss additive can resist salt until saturation, and it can control fluid loss in 24 mL·(30 min)−1 when its dosage is 2%. The fluid loss additive can achieve the effect of fluid loss reduction by increasing the filtrate viscosity, forming a flexible elastic ad... [more]
Polyimide (PI) Composite Spunlace Nonwovens for Hygiene Material with Excellent Comfort and Antimicrobial Properties
Hao Lu, Minggang Lin, Tan Li, Hongjie Zhang, Lili Feng, Chuyang Zhang
June 7, 2024 (v1)
Subject: Materials
Keywords: air plasma treatment, antibacterial, facing materials, polyimide, spunlace nonwovens
Nonwoven fabrics with appropriate hydrophilicity and potent antimicrobial properties hold important promise for hygiene applications. However, existing materials with certain limitations and complex manufacturing steps, along with the unavoidable use of chemicals in the process, are limited to a certain extent in terms of the balance between comfort and antimicrobial properties. In this paper, a polyimide (PI) fiber was reported to be used for the preparation of PI composite nonwoven fabrics (5-P), which can effectively enhance the surface hydrodynamic and antimicrobial properties of the nonwoven by a one-step plasma treatment on one side. After treatment, the one-sided water contact angle (WCA) changed from 121.5° to 68.5°, and the permeation volume from 0.7 to 2.1 g, with a relative increase of 181.9%. Meanwhile, the reverse osmosis amount was only 0.5 g, achieving rapid permeation while keeping a low reverse osmosis amount. The antimicrobial experiment showed that plasma-treated 5-P... [more]
Copper and Copper Nanoparticles Applications and Their Role against Infections: A Minireview
Iliana A. Ivanova, Dragomira S. Daskalova, Lilia P. Yordanova, Elitsa L. Pavlova
June 7, 2024 (v1)
Subject: Materials
Keywords: antibacterial, antifungal, antiviral, coatings, copper, nanoparticles
The focus of this review article is to present a retrospective analysis of copper applications focusing on ions and nanoparticles as broad-spectrum antimicrobials. Copper nanoparticles are presented as an alternative to rising antibiotic resistance. The basic mechanisms of bacterial, fungal, and viral inactivation, which explain their potential, are presented. The green biosynthesis of copper nanoparticles using biomaterials is also presented and considered a very promising trend for future biotechnology and medical applications.
Ionic Liquids as Potential Cleaning and Restoration Agents for Cellulosic Artefacts
Catalin Croitoru, Ionut Claudiu Roata
June 7, 2024 (v1)
Subject: Materials
Keywords: cellulose, cleaning agents, ionic liquids, paper, reconditioning agents, restoration
This study explores the efficacy of 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and 1-hexyl-3-methylimidazolium chloride as cleaning agents for aged cellulosic artifacts. A 10% v/v acetone solution of these ionic liquids (ILs) effectively removes the brownish-yellow color of aged paper in a 10 min immersion treatment. Colorimetric analysis shows a remarkable increase in lightness (L*) by up to 40% and a decrease in red/brownish tones (b*) after IL treatment. The cleaning process also deacidifies the paper, shifting the pH to neutral-slightly basic levels and enhancing its long-term stability. Optimal pH outcomes are achieved, with ionic liquid consumption values of 0.4−0.6 g/g of paper. The FTIR analysis revealed structural changes in cellulose induced by the washing step, which is mainly due to the reorganization effect imparted by the ionic liquids. Furthermore, ILs mobilized degraded compounds and acidic species, aiding in their extraction during the restoration pr... [more]
Dramatically Enhancing Oil Recovery via High-Efficient Re-Fracturing Horizontal Wells in Ultra-Low Permeability Reservoirs: A Case Study in HQ Oilfield, Ordos Basin, China
Shanbin He, Ting Huang, Xiaohu Bai, Jiawei Ren, Kun Meng, Hongyan Yu
June 7, 2024 (v1)
Subject: Materials
Keywords: development programs, horizontal wells, re-fracturing, reservoir evaluation, ultra-low permeability reservoir
The ultra-low permeability oil reservoir in the HQ oilfield within the Ordos Basin exemplifies a classic “three-low” oil reservoir characterized by low pressure, low permeability, and low abundance. Upon the commencement of oil well production, substantial initial production decline and inadequate pressure maintenance levels are encountered. Consequently, these wells commonly face persistent low production issues resulting from ineffective water injection. Currently, the available technical approaches for repeated stimulation of such wells to enhance production and efficiency are limited, thereby restricting the effective utilization of the remaining oil reserves. In response to this challenge, this article presents an innovative technology tailored for high-efficiency re-fracturing to improve oil recovery in ultra-low permeability reservoirs. Grounded in the theory of multiple flow couplings and volume development, this technology introduces a novel integrated process encompassing see... [more]
Tensile Behavior of Parts Manufactured Using a Material Extrusion Process from a Filament with Short Carbon Fibers and PET Matrix
Madalina-Ioana Blaj, Sebastian-Marian Zaharia, Cristin Olimpiu Morariu, Mihai Alin Pop, Mihaela Cosnita, Gheorghe Oancea
June 7, 2024 (v1)
Subject: Materials
Keywords: manufacturing defects, mechanical properties, MEX process, microscopy, PET, short carbon fibers
One of the latest tendencies in research related to material extrusion based on additive manufacturing is to determine the mechanical characteristics of parts taking into consideration the most influential manufacturing parameters. The main research objective is to describe how the manufacturing parameters, part orientation, layer thickness and infill density influence the tensile behavior of specimens made from PET with 15% short carbon fibers. The most advantageous result is obtained for a layer thickness of 0.15 mm, with 100% material infill, and material deposition on the longitudinal direction of the part. The obtained mean values are: 65.4 MPa tensile strength, 1.93% strain at rupture, and 9 GPa Young Modulus. For these values, the tensile behavior of specimens manufactured along transverse and thickness directions are presented. The least favorable results are obtained for manufacturing by thickness. The novelty of the discussed research consists in all these aspects together wi... [more]
Preparation of Nickel-Based Bimetallic Catalyst and Its Activation of Persulfate for Degradation of Methyl Orange
Bo Zhang, Jiale Li, Zhizhi Xu, Xiaohong Xu, Chundu Wu
June 7, 2024 (v1)
Subject: Materials
Keywords: advanced oxidation, catalyst, methyl orange, persulfate
In this research, a new catalyst for activating persulfate was developed by loading iron and nickel ions onto powdered activated carbon (PAC) for treating methyl orange, and the preparation process was optimized and characterized. The efficacy of the treatment was evaluated using the Chemical Oxygen Demand (COD) removal rate, which reflects the impact of various process parameters, including catalyst dosage, sodium persulfate dosage, and reaction pH. Finally, the recovery and reuse performance of the catalyst were studied. The optimal conditions for preparing the activated sodium persulfate catalyst were determined to be as follows: a molar ratio of Fe3+ and Fe2+ to Ni of 4:1, a mass ratio of Fe3O4 to PAC of 1:4, a calcination temperature of 700 °C, and a calcination time of 4 h. This preparation led to an increase in surface porosity and the formation of a hollow structure within the catalyst. The active material on the surface was identified as nickel ferrite, comprising the elements... [more]
Migration and Transformation of Heavy Metal and Its Fate in Intertidal Sediments: A Review
Nan Geng, Yinfeng Xia, Dongfeng Li, Fuqing Bai, Cundong Xu
June 7, 2024 (v1)
Subject: Materials
Keywords: bioaccumulation, heavy metal, intertidal sediment, migration, transformation
Intertidal sediments are rich in biological resources, which are important for material circulation and energy exchange. Meanwhile, these areas can be treated as sinks as well as sources of coastal heavy metal pollutants. Due to the influence of the tide, the intertidal sediments are in a state of periodic flooding and exposure, and environmental factors such as dissolved oxygen, salinity and overlying water pressure are changeable. Heavy metals in sediments are prone to migration and transformation with the dynamic effects of tidal water and the changes in the environment factors, which increase the bioavailability of heavy metals. In this review, the characteristics of distribution and the bioavailability of heavy metals in intertidal sediments are described; the migration and transformation behavior of heavy metals and its influencing factors under tidal conditions are analyzed; and the mechanisms of heavy metal’s migration and transformation in the intertidal zone are summarized. M... [more]
Recent Progress in Electrochemical CO2 Reduction at Different Electrocatalyst Materials
Marcela Miranda Barcelos, Maria de Lourdes Soprani Vasconcellos, Josimar Ribeiro
June 7, 2024 (v1)
Subject: Materials
Keywords: Carbon Dioxide, copper, electrocatalysts, electroreduction of CO2, nickel, zinc
Given the environmental problems caused by burning fossil fuels, it is believed that converting carbon dioxide (CO2) into chemical inputs is a great ally to generating clean energy. In this way, investigative studies related to electrochemical CO2 reduction (CO2RE) concerning the behavior of metal catalysts have received attention about the processes involved. CO2RE can be an important tool to mitigate the presence of this gas in the Earth’s atmosphere. Given these considerations, in this review, we report the main catalysts used to act as CO2RE. Among them, we emphasize catalysts based on Ni, Zn, and Cu, which encompass the main properties related to the electrochemical conversion of CO2. Regarding the Cu-based catalyst, it presents high conversion efficiency but low selectivity. Furthermore, we also describe the main mechanisms related to the electrochemical conversion of CO2.
Utilization of Silicon Dust to Prepare Si3N4 Used for Steelmaking Additives: Thermodynamics and Kinetics
Qian Hu, Zhengliang Xue, Shengqiang Song, Robert Cromarty, Yiliang Chen
June 7, 2024 (v1)
Subject: Materials
Keywords: catalytic nitridation, dynamics, growth mechanism, silicon dust, silicon nitride
Silicone monomers are the basic raw materials for the preparation of silicone materials. The secondary dust generated during the preparation of silicone monomer by the Rochow−Müller method is a fine particulate waste with high silicon content. In this paper, the physical and chemical properties of silicon powder after pretreatment were analyzed, and an experimental study was conducted on the use of silicon dust in the preparation of Si3N4, a nitrogen enhancer for steelmaking, by direct nitriding method in order to achieve the resourceful use of this silicon dust. Furthermore, the thermodynamics and kinetics of the nitriding process at high temperatures were analysed using FactSage 8.1 software and thermogravimetric experiments. The results indicate that after holding at a temperature range of 1300~1500 °C for 3 h, the optimal nitriding effect occurs at 1350 °C, with a weight gain rate of 26.57%. The nitridation of silicon dust is divided into two stages. The first stage is the chemical... [more]
Mechanical Characterization of the Frozen and Thawed States of Coal after the Action of LN2 at In Situ Formation Pressure
Lei Qin, Pengfei Liu, Hui Wang, Botao Li, Ruizhe Wang, Jiawei Li, Rongwei Luo, Shiyin Lv
June 7, 2024 (v1)
Subject: Materials
Keywords: different freezing states, different siege pressures, energy evolution, LN2 fracturing, mechanical properties
Coal penetration enhancement technology is the key to increase the production of coalbed methane. Coal bodies are subjected to different peripheral pressures in the in situ strata, and the study of the changes in the mechanical strength of coal bodies under different peripheral pressures after the action of liquid nitrogen is crucial for the penetration enhancement of liquid nitrogen (LN2)-fractured coal. In this paper, an MTS universal testing machine was utilized to carry out experiments to obtain the stress−strain curves of the coal under different freezing times under 1 MPa surrounding pressure and different surrounding pressures after 50 min of LN2 action. The experimental results showed the following: (1) the uniaxial compressive strength and peak strain of coal samples in a frozen state are positively correlated under two conditions. The modulus of elasticity decreased before 100 min at different times of LN2 action, and the modulus of elasticity was maximum at 5 MPa at differen... [more]
Expansion Characteristics and Creep Test of New Curing Expansion Material for Gas Extraction Boreholes
Lijuan Jiang, Ruoyu Bao, Changkui Lei
June 7, 2024 (v1)
Subject: Materials
Keywords: concentric ring, creep characteristics, drilling sealing, gas extraction, stress concentration
In order to find the optimal expansion effect of a new curing expansion material so that it can better meet the requirements of the efficient sealing of drilled holes, the expansion and creep characteristics of the new curing expansion material were studied. Based on the creep results of graded loading, the Kelvin−Volgt model was selected to analyze its mechanical parameters, and a new “concentric ring” reinforcement sealing method was proposed. Numerical simulation was employed to analyze and discuss the reinforcement radius and depth of the “protective wall rock hole ring” in the “concentric ring” model, and on-site application experiments were carried out in a soft coal seam. The results show that the “concentric ring” reinforcement sealing method can effectively solve the problems of easy collapse and stress concentration instability in the sealing section of soft coal seams, ensuring long-term and efficient sealing of gas extraction boreholes in soft coal seams. When the diameter... [more]
Optimization of Ternary Activator for Enhancing Mechanical Properties of Carbonized Cementitious Material Based on Circulating Fluidized Bed Fly Ash
Nuo Xu, Suxia Ma, Nana Wang, Yuchuan Feng, Yunqi Liu, Ke Ren, Shanshui Bai
June 7, 2024 (v1)
Subject: Materials
Keywords: artificial neural network, Box–Behnken design, Genetic Algorithm, response surface methodology, ternary activator
In this study, circulating fluidized bed fly ash (CFBFA) non-sintered ceramsite was innovatively developed. The CFBFA was addressed by adding ternary activator (including cement, hydrated lime, and gypsum) to prepare ceramsite. In the curing process, the use of power plant flue gas for curing not only captured greenhouse gas CO2, but also enhanced the compressive strength of the ceramsite. The compressive strength of the composite gravels prepared by the CFBFA was modeled using a novel approach that employed the response surface methodology (RSM) and artificial neural network (ANN) coupled with genetic algorithm (GA). Box−Behnken design (BBD)-RSM method was used for the independent variables of cement content, hydrated lime content, and gypsum content. The resulting quadratic polynomial model had an R2 value of 0.9820 and RMSE of 0.21. The BP-ANN with a structure of 3-10-1 performed the best and showed better prediction of the response than the BBD-RSM model, with an R2 value of 0.9932... [more]
The Textural and Physical Characteristics of Red Radishes Based on a Puncture Test
Mariana Lupu, Valentin Nedeff, Mirela Panainte-Lehadus, Emilian Mosnegutu, Claudia Tomozei, Dana Chitimus, Dragos-Ioan Rusu
June 7, 2024 (v1)
Subject: Materials
Keywords: penetration force, puncture test, red radishes, storage conditions, texture analysis
Texture is an important indication of the quality of food products, and the analysis of texture involves the measurement of their response when subjected to mechanical forces, such as cutting, scissoring, chewing, and compression or stretching. There is a close correlation between the texture of agri-food products and their mechanical properties. In this study, the textural characteristics of red radish roots were analyzed under different storage conditions using a penetration test. The physical parameters analyzed are the skin strength and elasticity, breaking point, ripening and softening profile, and flesh firmness. The results of the breaking point after the products’ storage at room temperature (tested after one, two, and three days, respectively) are: 184.96 N, 151.29 N, and 154.42 N, respectively; for radishes stored at a temperature of 2.8 °C, the breaking point is: 132.12 N, 109.76 N, and 141.16 N, respectively. The lowest value of firmness is recorded for the radishes tested... [more]
Biofilm Formation in Water Distribution Systems
Patrícia Erdei-Tombor, Gabriella Kiskó, Andrea Taczman-Brückner
June 7, 2024 (v1)
Subject: Materials
Keywords: chlorine-resistant bacteria (CRB), DWDS, HDPE, pipes, Pseudomonas, PVC
A biofilm is a biologically active matrix attached to the surface of cells and their extracellular products. As they are a mixture of many microorganisms, the microbiological activity of biofilms varies according to their position in the aggregate. With particular emphasis on drinking water distribution systems, this review focuses on the process of biofilm formation, associated bacteria, chlorine resistance of bacteria, and the predominant surface materials. We have compiled studies on the bacteria in drinking water distribution systems and their interactions with biofilm formation on different materials, and we also analysed the chlorine-resistant bacteria and their problems in the water networks. The materials used in the drinking water network are significantly affected by the disinfection method used to produce the biofilm that adheres to them. Some studies propose that the material is inconsequential, with the disinfection process being the most significant factor. Studies sugges... [more]
Quantitative Analysis of Near-Infrared Spectroscopy Using the BEST-1DConvNet Model
Gang Li, Shuangcheng Deng
June 7, 2024 (v1)
Subject: Materials
Keywords: Bayesian optimization, chemometric predictions, convolutional neural networks (CNN), near-infrared spectroscopy (NIRS), quantitative analysis, support vector machine (SVM)
In the quest for enhanced precision in near-infrared spectroscopy (NIRS), in this study, the application of a novel BEST-1DConvNet model for quantitative analysis is investigated against conventional support vector machine (SVM) approaches with preprocessing such as multiplicative scatter correction (MSC) and standard normal variate (SNV). We assessed the performance of these methods on NIRS datasets of diesel, gasoline, and milk using a Fourier Transform Near-Infrared (FT-NIR) spectrometer having a wavelength range of 900−1700 nm for diesel and gasoline and 4000−10,000 nm for milk, ensuring comprehensive spectral capture. The BEST-1DConvNet’s effectiveness in chemometric predictions was quantitatively gauged by improvements in the coefficient of determination (R2) and reductions in the root mean square error (RMSE). The BEST-1DConvNet model achieved significant performance enhancements compared to the MSC + SNV + 1D + SVM model. Notably, the R2 value for diesel increased by approximat... [more]
Heteroatom-Doped Carbon-Based Catalysts Synthesized through a “Cook-Off” Process for Oxygen Reduction Reaction
Ruiquan Zhang, Qiongyu Liu, Ming Wan, Zhenhua Yao, Maocong Hu
June 7, 2024 (v1)
Subject: Materials
Keywords: “cook-off” process, heteroatom doping, metal-free catalyst, oxygen reduction reaction
The development of efficient and low-cost non-metallic catalysts is of great significance for the oxygen reduction reaction (ORR) in fuel cells. Heteroatom-doped carbon-based catalysts are one of the popular candidates, although their preparation method is still under exploration. In this work, single (CS)-, double (NCS)-, and triple (NBCS)-heteroatom-doped carbon-based catalysts were successfully prepared by a “cook-off” process. The morphology, elemental composition, and bonding structure of the catalysts were investigated by SEM, TEM, Raman spectra, BET, and XPS. ORR catalytic performance measurements suggested an activity trend of CS < NCS < NBCS, and NBCS demonstrated better methanol resistance and slightly higher stability than the commercial Pt/C catalyst, as evaluated with both rotating disk electrode (RDE) and rotating ring-disk electrode (RRDE) systems. The mechanism for the promoted performance was also proposed based on the conductivity of the catalysts. In this paper... [more]
Modeling of Triphenyl Phosphate Surfactant Enhanced Drying of Polystyrene/p-Xylene Coatings Using Artificial Neural Network
Devyani Thapliyal, Rahul Shrivastava, George D. Verros, Sarojini Verma, Raj Kumar Arya, Pramita Sen, Shiv Charan Prajapati, Chahat, Ajay Gupta
June 7, 2024 (v1)
Subject: Materials
Keywords: ANN modeling, poly(styrene), surfactant enhanced drying, thin films, triphenyl phosphate
The drying process of polymeric coatings, particularly in the presence of surfactants, poses a complex challenge due to its intricate dynamics involving simultaneous heat and mass transfer. This study addresses the inherent complexity by employing Artificial Neural Networks (ANNs) to model the surfactant-enhanced drying of poly(styrene)-p-xylene coatings. A substantial dataset of 16,258 experimentally obtained samples forms the basis for training the ANN model, showcasing the suitability of this approach when ample training data is available. The chosen single-layer feed-forward network with backpropagation adeptly captures the non-linear relationships within the drying data, providing a predictive tool with exceptional accuracy. Our results demonstrate that the developed ANN model achieves a precision level exceeding 99% in predicting coating weight loss for specified input values of time, surfactant amount, and initial coating thickness. The model’s robust generalization capability e... [more]
Xylanase Production by Cellulomonas phragmiteti Using Lignocellulosic Waste Materials
Kata Buda, Tünde Fekete, Ornella M. Ontañon, Eleonora Campos, Csaba Fehér
June 7, 2024 (v1)
Subject: Materials
Keywords: bacterial enzymes, enzyme fermentation, enzyme stability, hemicellulases, waste valorization, xylanase characterization
Lignocellulosic biomass holds promise as a renewable feedstock for various applications, but its efficient conversion requires cost-effective degradation strategies. The main objective of this study was to investigate the effect of the growth conditions of Cellulomonas phragmiteti in the production of (hemi)cellulosic supernatants. To meet this aim, different lignocellulosic residues were used as carbon sources for growth using defined mineral or nutritive culture media. Cell-free culture supernatants with xylanolytic activity were produced in all the conditions evaluated, but the highest xylanase activity (15.3 U/mL) was achieved in Luria−Bertani (LB) medium containing 1% waste paper. Under these conditions, almost negligible β-glucosidase, cellobiohydrolase, β-xylosidase, and α-arabinofuranosidase activity was detected. The xylanolytic supernatant showed tolerance to salt and displayed maximal catalytic efficiency at pH 6 and 45 °C, along with good activity in the ranges of 45−55 °C... [more]
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