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Records with Type: Published Article
2787. LAPSE:2023.36669
Soy Protein Nanofibers Obtained by Solution Blow Spinning
September 20, 2023 (v1)
Subject: Biosystems
Keywords: nanofibers, polyethylene oxide, solution blow spinning, soy protein isolate
The climate crisis, growing pollution of the environment with waste, and ubiquitous microplastics have encouraged the search for new methods and new opportunities to use natural materials in the least harmful processes. Replacing synthetic materials with raw materials is not only a matter of “fashion”, but also a necessity. Therefore, this study aimed to produce fibers from an aqueous solution containing the highest possible concentration of soy protein isolate (SPI) through solution-blowing. As the aqueous solution of SPI has no fiber-forming potential, polyethylene oxide (PEO) was used as the carrier/matrix. The rheology of the aqueous PEO solution and PEO/SPI blends (flow curves, loss modulus, and storage modulus) was then analyzed. The proportions of the PEO/SPI mixtures and the process parameters were determined on this basis. As a result of the conducted research, nanofibers were produced from water solutions of PEO/SPI with a soy protein content of up to 7.88%, with a PEO share... [more]
2788. LAPSE:2023.36668
An Early Study on the Synthesis of Lignin-Graft-(Net-Poly(acrylamide-co-N,N′methylenebisacrylamide)), Characterization of the Produced Copolymer, and Evaluation of Its Performance as Adsorbent for Lead Removal from Wastewater Purposes
September 20, 2023 (v1)
Subject: Materials
Keywords: adsorbents, lead adsorption, polymer grafting, polymer modification
A lignin-graft-(net-poly(acrylamide-co-N,N′methylenebisacrylamide)) copolymer was synthesized by conventional free-radical crosslinking copolymerization using conventional and microwave heating. Grafting of the polymer network onto lignin was confirmed by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), and elemental analysis. The performance of the modified materials for the removal of lead from water was evaluated. The materials obtained by the two types of heating showed excellent removal efficiencies: sample HLigAM4h, 96%; and sample HLigAMMW5, 86%. The maximum adsorption capacity of HLigAM4h was 209.82 mg g−1. The obtained copolymer (sample HLigAM4h) was characterized by X-ray photoelectron spectroscopy (XPS) and SEM/EDS after its evaluation as an adsorbent, which confirm the adsorption of Pb2+. This is the first of a series of st... [more]
2789. LAPSE:2023.36667
Pressurized Liquid Extraction (PLE) in an Intermittent Process as an Alternative for Obtaining Passion Fruit (Passiflora edulis) Leaf Hydroalcoholic Extract (Tincture)
September 20, 2023 (v1)
Subject: Food & Agricultural Processes
Keywords: Extraction, Fick’s Law, high-pressure, intermittent process, isovitexin, phenolic compounds
Tinctures are medicinal plant extracts obtained by extraction with a hydroalcoholic solution (70%) by percolation (PER). This process takes about 26 h to prepare, in addition to using a large amount of solvent. In our research, passion fruit leaf tinctures were obtained using extract with the same pressurized hydroalcoholic solution as in an intermittent process. The objective was to demonstrate that this emerging technology can be economical and profitable. An optimization using Central Composite Rotatable Design (CCRD) was performed to evaluate the influence of process variables on the yields and compositions of the extracts. The temperature (T) was the factor that most influenced the responses. Extraction with pressurized liquid (PLE) provided total yields and total phenolic and flavonoid contents in greater amounts than PER. The optimized conditions of the process variables studied in the CCRD for the highest content of total phenolics (43.2 mg GAE/g) and flavonoids (58.8 mg QE/g)... [more]
2790. LAPSE:2023.36666
Plasma-Arc-Flow Technology for Sustainable Treatment of High-Impact Fluid Waste: A Graphene-Based Material for Industrial-Wastewater Purification
September 20, 2023 (v1)
Subject: Materials
Keywords: Energy Efficiency, graphene, Optimization, plasma arc flow, wastewater treatment
The research presented aimed to address the treatment of fluid waste with significant environmental impact by utilizing plasma technology, specifically plasma arc flow (PAF). The goal was to develop a novel purification material based on graphene for industrial applications and to optimize the treatment process. Analysis and monitoring of a submerged arc plasma reactor were the main goals of this research. This entailed a careful examination of the incoming wastewater that needed to be treated with the goal of identifying its precise composition characteristics with the relative tolerances needed for the reactions that were to follow in the reactor. The focus of the analysis was on input-parameter optimization, production of characteristic curves, and analysis of the factors affecting hydrogen evolution in syngas. Additionally, the study investigated how to determine the best viscosity for a particular input matrix by carrying out an evaluation study. The effects of this parameter were... [more]
2791. LAPSE:2023.36665
Pyridazinic Bioisosteres with Potential Applications in Medicinal Chemistry and Agriculture
September 20, 2023 (v1)
Subject: Biosystems
Keywords: antibacterial and antifungal activity, classical and nonclassical bioisosteres, height and weight of plantlets, microwave, pyridazine compounds, seedling growth, spectral characterisation, stereochemistry, synthesis, wheat germination
Bioisosteres are substituents or groups (atoms, ions, or molecules) with similar chemical or physical properties, and which usually have similar biological properties. Pyridazine and its derivatives are invaluable scaffolds in medicinal chemistry, having a large variety of activities such as antibacterial, antifungal, antimalarial, anticancer, antituberculosis, antihypertensive, etc. Also, the pyridazine core is of high interest in agriculture, being used as a growth factor for plants, herbicides, etc. This study aims to review our previous contributions related to antimicrobials and the germination and seedling capabilities of some seeds and plants of some pyridazine classical and nonclassical bioisosteres. So, we present herein the synthesis (under conventional thermal heating and microwave irradiation) and spectral characterization of seven series of pyridazine bioisosteres, the in vitro antimicrobial activity (against different strains of Gram-positive and Gram-negative bacteria an... [more]
2792. LAPSE:2023.36664
Deformation Characteristics of Asymmetric Gradient Extrusion in Preparing Ultra-Fine-Grained Bulk Materials
September 20, 2023 (v1)
Subject: Materials
Keywords: asymmetric gradient extrusion, deformation characteristics, finite element analysis, slip line field, ultra-fine-grained bulk materials
In this paper, a novel method for the preparation of ultra-fine-grained bulk materials called asymmetric gradient extrusion (AGE) is proposed. In AGE, the cross-section of the extrusion channel is a rectangle, and two inclined planes are staggered along the extrusion direction. To realize repetitive extrusion, the thickness of the workpiece is limited to be equal to the width of the channel outlet. In order to study the mechanism of ultra-fine grain formation in AGE, the deformation characteristics of AGE were investigated. First, the slip line field method was used to theoretically analyze the deformation characteristics and grain splitting in AGE. Then, the plastic deformation behavior of bulk samples in AGE and traditional extrusion was investigated and compared with the finite element method. In addition, the deformation characteristic and microstructure variation of pure copper bulk samples in AGE were experimentally investigated. The results showed that the deformation characteri... [more]
2793. LAPSE:2023.36663
Three-Dimensional Analysis of the Flow Characteristics Induced by a Cubic Artificial Reef with Diversions
September 20, 2023 (v1)
Subject: Process Design
Keywords: cubic artificial reef with diversion, cut-opening ratio, flow characteristics, flow velocity, three-dimensional analysis
In this paper, the flow characteristics induced by a cubic artificial reef with diversions (DCAR) were investigated using computational fluid dynamics (CFD). The results showed that the design of a DCAR can greatly improve the flow field range compared to typical cubic artificial reefs. The upwelling volume of the DCAR was more than 16 times that of a typical cubic artificial reef. The flow field effect produced the best results when the cut-opening ratio (COR) was 0.1−0.2 with constant flow. The parameters of the upwelling and back vortex increased with an increase in the flow velocity, and it decreased with an increase in the COR. The drag coefficient was less affected by the flow velocity, which remained between 1.32 and 1.44. The new type of artificial reef can improve the flow characteristics around the reefs.
2794. LAPSE:2023.36662
Effect of Atmospheric Cold Plasma on the Aroma of Pineapple Juice: Improving Fresh and Fruity Notes and Reducing Undesired Pungent and Sulfurous Aromas
September 20, 2023 (v1)
Subject: Food & Agricultural Processes
Keywords: Ananas comosus, aroma, dielectric barrier discharge plasma, food chemistry, quality
Pineapple aroma is characterized by several esters, which confers its fresh and fruity aroma. However, high concentrations of methyl hexanoate and thioesters bring an undesired pungently sweet aroma and sulfurous notes to pineapple juice. This study investigates the chemical effects of cold plasma on the aroma compounds and descriptors of pineapple juice, evaluating the effects of plasma on its esters and thioesters. Dielectric barrier discharge plasma was applied to pineapple juice, varying the excitation frequency (50 to 1000 Hz) and processing time (10 to 20 min) at constant voltage (20 kV). Plasma treatment induced successive demethylation of esters and the conversion of methyl esters into ethyl esters. Thioesters showed to be more stable under plasma treatment. Proper setting of plasma operating conditions enabled an improvement in the fresh and fruity descriptors of pineapple juice, a reduction of its undesired pungently sweet aroma, but an increase in the influence of sulfurous... [more]
2795. LAPSE:2023.36661
Sedimentary Genesis and Model Analysis of Shale Lithofacies in Jiyang Depression
September 20, 2023 (v1)
Subject: Other
Keywords: Jiyang depression, lithofacies types, paleogene, sedimentary genesis, sedimentary model, shale
Based on core observation, rock thin sections, logging data, and testing data, taking the shale of the upper submember of the 4th Member to the lower submember of the 3rd Member of Paleogene Shahejie Formation in Jiyang Depression of Bohai Bay Basin as an example, we determine the lithofacies division scheme, divide the main lithofacies types, analyze the sedimentary origin and development location of different shale lithofacies, establish the continental lake basin sedimentary model, determine the types and enrichment areas of favorable lithofacies, and provide guidance for the exploration and development of Shale oil. The results show that: (1) According to the mineral composition, sedimentary structure, and organic matter abundance, the division scheme of shale lithofacies in the study area is proposed, and the shale lithofacies of the study area was mainly divided into 17 types. (2) Based on the lithologic changes, the lacustrine sedimentary shale area was divided into muddy water... [more]
2796. LAPSE:2023.36660
Prediction of Marine Thin Shale Gas Reservoir with Seismic Phase-Controlled Nonlinear Stochastic Inversion
September 20, 2023 (v1)
Subject: Energy Systems
Keywords: nonlinear stochastic inversion, reservoir prediction, seismic facies, shale gas, thin layer
Due to the complicated interference sources and low signal-to-noise ratio of seismic records, conventional seismic inversion methods are difficult to accurately identify shale gas reservoirs with a thickness of less than 10 m. This presents great challenges to shale gas exploration and development in China. Seismic phase-controlled nonlinear stochastic inversion (SPCNSI) is related to the heterogeneity of underground media. With the constraints of the stratigraphic sequence or seismic facies models, the minimum value between the seismic model and seismic record can be solved through iterative processes. Based on the solved acoustic velocity in formation, the constraints for SPCNSI can be formed with the matching relationship between target layers and different sequences in three-dimensional space. The prediction resolution of an unconventional reservoir can be effectively improved by combining logging, geological and seismic information. The method is suitable for predicting thin shale... [more]
2797. LAPSE:2023.36659
Breaking New Ground: Exploring the Promising Role of Solid-State Fermentation in Harnessing Natural Biostimulants for Sustainable Agriculture
September 20, 2023 (v1)
Subject: Food & Agricultural Processes
Keywords: crop improvement, natural biostimulant, organic waste, solid-state fermentation, sustainable agriculture
Agriculture has been experiencing a difficult situation because of limiting factors in its production processes. Natural biostimulants (NBs) have emerged as a novel alternative. This study reviews NBs produced through solid-state fermentation (SSF) from organic waste, focusing on processes and production methods. The aim is to highlight their potential for improving agricultural productivity and promoting sustainable agriculture. Through a literature review, the effects of NBs on crops were summarized, along with the challenges associated with their production and application. The importance of standardizing production processes, optimizing fermentation conditions, and assessing their effects on different crops is emphasized. Furthermore, future research areas are introduced, such as enhancing production efficiency and evaluating the effectiveness of SSF-produced NBs in different agricultural systems. In conclusion, SSF-produced NBs offer a promising alternative for sustainable agricul... [more]
2798. LAPSE:2023.36658
A Cloud-Edge Computing Method for Integrated Electricity-Gas System Dispatch
September 20, 2023 (v1)
Subject: Energy Policy
Keywords: cloud-edge computing, integrated electric–gas system, MADDPG, optimal dispatch
An integrated electric−gas system (IEGS) is the manifestation and development direction of a modern smart power system. This paper employs the cloud-edge computing method to research IEGS’s optimal dispatch to satisfy data protection requirements between power systems and natural gas systems and reduce data transmission pressure. Based on cloud-edge computing architecture, this paper constructs a cloud-edge computing method based on the Multi-agent Deep Deterministic Policy Gradient (MADDPG) algorithm to solve optimal dispatch problems. Then, this paper proposes an IEGS dispatch strategy based on cloud-edge computing, which conducts distributed computing independently at the edge of power and natural gas, and the cloud implements global dispatch based on boundary information and edge learning parameters. This method does not require the exchange of all information between the power system and natural gas system, effectively protecting data privacy. This paper takes the improved IEGS of... [more]
2799. LAPSE:2023.36657
Evaluation and Prediction of the Effect of Fabric Wetting on Coolness
September 20, 2023 (v1)
Subject: Modelling and Simulations
Keywords: coolness sensation, random forest regression model, sensory evaluation, thermal absorptivity, wet state
As an important parameter of garment comfort, the thermal sensation of fabrics changes with factors such as sweat-induced humidity, making it a crucial area of research. To explore the coolness sensation of fabrics under different humidities, we tested heat transfer between fabrics and skin for 20 different fabrics with varying thermal absorption rates using fuzzy comprehensive evaluation to objectively assess their coolness levels. Subjective evaluation was then obtained by having subjects touch the fabrics and provide feedback, resulting in a subjective evaluation of their coolness levels. We compared the objective and subjective evaluations and found them to be highly consistent (R2 = 0.909), indicating accurate objective classification of fabric coolness levels. Currently, random forest regression models are widely used in the textile industry for classification, identification, and performance predictions. These models enable the prediction of fabric coolness levels by simultaneou... [more]
2800. LAPSE:2023.36656
Formation Characterization and Type Prediction Based on Geophysical Well Log Data in Horizontal Well: A Case Study of Triassic Chang 8 Formation in Shunning Region, Central Ordos Basin
September 20, 2023 (v1)
Subject: Materials
Keywords: anisotropy analysis, formation classification, formation physical properties, pore structure
The role of the horizontal well in developing unconventional oil and gas reservoirs is particularly significant. Different from vertical wells, horizontal wells are greatly affected by many factors, e.g., well track, surrounding mudstone, resistivity, and pore structure heterogeneity in horizontal and vertical directions. These make it difficult to evaluate reservoir parameters and determine optimized test layers. In order to improve formation evaluation in horizontal wells, it is necessary to carry out the research of analyzing formation anisotropy, predict physical property parameters, and classify formation to determine high-quality intervals. In this study, taking Triassic Chang 8 Formation in Shunning Region, Central Ordos Basin as an example, 40 core samples were drilled and applied for nuclear magnetic resonance (NMR), mercury injection capillary pressure (MICP), and resistivity experiments. The porosity, permeability, resistivity, and pore structure anisotropy are analyzed. Res... [more]
2801. LAPSE:2023.36655
A New Approach to the Preparation of Stable Oxide-Composite Cobalt−Samarium Catalysts for the Production of Hydrogen by Dry Reforming of Methane
September 20, 2023 (v1)
Subject: Reaction Engineering
Keywords: cobalt–samarium oxide catalysts, dry reforming of methane, heterogeneous catalysis, Hydrogen, Syngas
A new approach to preparing a series of Co/Sm2O3 catalysts for hydrogen production by the dry reforming of methane has been developed. The catalyst precursors were synthesized with a simple method, including the evaporation of aqueous solutions of cobalt and samarium nitrates, followed by a short-term calcination of the resulting material. The as-prepared and spent catalysts were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, temperature-programmed reduction, and thermogravimetric analysis. The content of cobalt in the synthesized materials affects their phase composition and carbonization resistance in the dry reforming of the methane reaction. It has been shown that preheating in N2 atmosphere produces catalysts that provide a stable yield of hydrogen and CO of 94−98% for at least 50 h at 900 °C. These yields are among the highest currently available for the dry reforming of methane catalysts made from Co-Sm complex oxides. It h... [more]
2802. LAPSE:2023.36654
Cadmium Elimination via Magnetic Biochar Derived from Cow Manure: Parameter Optimization and Mechanism Insights
September 20, 2023 (v1)
Subject: Numerical Methods and Statistics
Keywords: artificial neural network, cadmium removal, cow manure, magnetic biochar, response surface methodology
Designing an efficient and recyclable adsorbent for cadmium pollution control is an urgent necessity. In this paper, cow manure, an abundant agricultural/animal husbandry byproduct, was employed as the raw material for the synthesis of magnetic cow manure biochar. The optimal preparation conditions were found using the response surface methodology model: 160 °C for the hydrothermal temperature, 600 °C for the pyrolysis temperature, and Fe-loading with 10 wt%. The optimal reaction conditions were also identified via the response surface methodology model: a dosage of 1 g·L−1, a pH of 7, and an initial concentration of 100 mg·L−1. The pseudo-second-order model and the Langmuir model were used to fit the Cd(II) adsorption, and the adsorption capacity was 612.43 mg·g−1. The adsorption was dominated by chemisorption with the mechanisms of ion-exchange, electrostatic attraction, pore-filling, co-precipitation, and the formation of complexations. Compared to the response surface methodology m... [more]
2803. LAPSE:2023.36653
CuFe2O4 Magnetic Nanoparticles as Heterogeneous Catalysts for Synthesis of Dihydropyrimidinones as Inhibitors of SARS-CoV-2 Surface Proteins—Insights from Molecular Docking Studies
September 20, 2023 (v1)
Subject: Biosystems
Keywords: Biginelli reaction, copper ferrite, COVID-19, dihydropyrimidinones, heterocycles, heterogeneous catalyst, hydroxychloroquine, molecular docking, multicomponent reaction, nanoparticles
In this study, we present the highly efficient and rapid synthesis of substituted dihydropyrimidinone derivatives through an ultrasound-accelerated approach. We utilize copper ferrite (CuFe2O4) magnetic nanoparticles as heterogeneous catalysts, employing the well-known Biginelli reaction, under solvent-free conditions. The impact of the solvent, catalyst amount, and catalyst type on the reaction performance is thoroughly investigated. Our method offers several notable advantages, including facile catalyst separation, catalyst reusability for up to three cycles with the minimal loss of activity, a straightforward procedure, mild reaction conditions, and impressive yields, ranging from 79% to 95%, within short reaction times of 20 to 40 min. Furthermore, in the context of fighting COVID-19, we explore the potential of substituted dihydropyrimidinone derivatives as inhibitors of three crucial SARS-CoV-2 proteins. These proteins, glycoproteins, and proteases play pivotal roles in the entry... [more]
2804. LAPSE:2023.36652
An Interpretable Predictive Model for Health Aspects of Solvents via Rough Set Theory
September 20, 2023 (v1)
Subject: Modelling and Simulations
Keywords: health indices, Machine Learning, organic solvents, rough set theory, rough set-based machine learning
This paper presents a machine learning (ML) approach to predict the potential health issues of solvents by uncovering the hidden relationship between substances and toxicity. Solvent selection is a crucial step in industrial processes. However, prolonged exposure to solvents has been found to pose significant risks to human health. To mitigate these hazards, it is crucial to develop a predictive model for health performance by identifying the contributing factors to solvent toxicity. This research aims to develop a predictive model for health issues related to solvent toxicity. Among various algorithms in ML, Rough Set Machine Learning (RSML) was chosen for this work due to its interpretable nature of the generated models. The models have been developed through data collection on the toxicity of various organic solvents, the construction of predictive models with decision rules, and model verification. The results reveal correlations between solvent toxicity and the Balaban index, vale... [more]
2805. LAPSE:2023.36651
Physical and Chemical Phenomena during the Production of Hydrogen in the Microwave Discharge Generated in Liquid Hydrocarbons with the Barbotage of Various Gases
September 20, 2023 (v1)
Subject: Materials
Keywords: discharge in liquids, gas chromatography, hydrogen production, microwave discharge, optical emission spectroscopy, shadow photographs
The physical and chemical characteristics of the microwave discharge in petroleum solvent during hydrogen production processes involving Ar, He, and CO2 barbotage were studied. Gas chromatography, emission spectroscopy, high-speed photography, and shadow photography were used for diagnosis. The results demonstrated the dependence of hydrogen yield on the flow rates of Ar, He, and CO2. The maximum yield values of hydrogen were 791 mL/min and 811 mL/min, while the maximum energy efficiency reached 135.6 NL/kWh and 162.2 NL/kWh in Nefras with Ar and He barbotage, respectively. The dynamics of discharge structure and the rotational and vibrational temperatures of C2 molecules were studied.
2806. LAPSE:2023.36650
Valorization of Peanut and Walnut Shells through Utilisation as Biosorbents for the Removal of Textile Dyes from Water
September 20, 2023 (v1)
Subject: Food & Agricultural Processes
Keywords: adsorption kinetics, biosorbents, dye removal, methylene blue, peanut shells, walnut shells
The present research focuses on the application of peanut and walnut shells, in their natural state, for the removal of methylene blue (MB) from water solutions in batch and dynamic (flow-through) conditions. Under batch conditions, at a 100 mg/L MB concentration of aqueous solution, the optimum dose of the studied biosorbents was determined to be 2.5 g/L, reaching about 95−97% efficiency of MB removal for both materials. Langmuir and Freundlich isotherms were used to model and evaluate the experimental data under different initial concentrations of MB (25 to 100 mg/L). The determined maximum adsorption capacities are 41.50 mg/g for walnut shells and 46.80 mg/g for peanut shells. Under flow-through conditions, breakthrough curves are determined for three sizes of fractions (<0.25 mm, 0.315−0.5 mm, and 0.8−1.6 mm). For peanut shells, the smaller the particle size, the higher the adsorption capacity and the column breakthrough time. For walnut shells, however, the particle size seems... [more]
2807. LAPSE:2023.36649
Environmental Life Cycle Analysis of Açaí (Euterpe oleracea) Powders Obtained via Two Drying Methods
September 20, 2023 (v1)
Subject: Environment
Keywords: açaí crop, environmental life cycle analysis, Euterpe oleracea, spray drying, vacuum drying, waste management
Açaí is a fruit native to Brazil that is found in Colombia, and it is recognized for containing more than 90 compounds with anticancer, anti-inflammatory, and other biological activities. In this study, a cradle-to-gate life cycle analysis (LCA) was conducted for the production of açaí powder, following the methodology outlined in the ISO 14040 standard. The investigation focused on examining the impact of utilizing or not utilizing the residues generated during the pulp extraction step as fertilizers. Four scenarios were analyzed and compared: (i) production of açaí powder via vacuum drying, (ii) via spray drying, and via the same two types of drying but using residues from the pulping operation as fertilizer (Scenarios 3 and 4). It was found that to produce 1 kg of açaí in a crop cycle, 1.17 kg of CO2 eq is produced. The drying stage in Scenarios 1 and 2 generated 8.04 and 7.93 kg of CO2 eq, respectively. Similarly, when solid waste is used as fertilizer, CO2 emissions barely increas... [more]
2808. LAPSE:2023.36648
Pore-Scale Experimental Investigation of the Residual Oil Formation in Carbonate Sample from the Middle East
September 20, 2023 (v1)
Subject: System Identification
Keywords: flow rate, micro-CT, microscopic remaining oil, pore-scale, porosity
Select porous carbonate cores are used to carry out water-flooding oil micro-CT flooding experiments, and use image processing to separate oil, water, microfacies, and rock skeleton. The gray value is used to determine the distribution position of the microfacies sub-resolution remaining oil. The gray image resolution is improved by the SRCNN method to improve the pore identification accuracy. The distribution and evolution law of the sub-resolution remaining oil after the displacement is determined by the oil-water distribution results. Using the SRCNN method, the pore recognition accuracy of the original scanned images of the two samples was increased by 47.88 times and 9.09 times, respectively. The sub-resolution residual oil and the macro-pore residual oil were determined from the CT scan images after the brine was saturated and divided into five categories. With the increase in the displacement ratio, the columnar and droplet residual oil of the low-permeability samples first incr... [more]
2809. LAPSE:2023.36647
Cause Analysis of Condensed Water Induced Bulging in High-Pressure Steam Tee Joints of a Pyrolyzer
September 20, 2023 (v1)
Subject: Materials
Keywords: altering thermal stress, bulging, condensed water, ratcheting, tee joint
High-pressure steam pipes inevitably suffered from the reciprocal interaction of high pressure and temperature during a long-period service, causing deformation and cracking. However, only limited studies about abnormal bulging caused by condensed water have been carried out. To study the relationship between bulging and condensed water, bulging tee joints belonging to high-pressure steam pipes were investigated with a macro visual inspection, chemical composition analysis, and metallographic microscopy. According to the analysis of the bulging samples, pearlite spheroidization was found in the abnormal bulging tee joint. The ANSYS FLUENT modeling indicated that the tube wall of bulging tees was continuously subjected to alternating stress, causing the cyclic transformation of the liquid−gas phase inside the tee joint. The results indicate that the stress produced by a condensed water droplet ranges from 532.8 MPa to 59 MPa, continuously exerting pressure on the tube wall of the tee jo... [more]
2810. LAPSE:2023.36646
Ammonia Decomposition over Alkali Metal (Li, K, Cs)-Promoted Bulk Mo2N Catalyst
September 20, 2023 (v1)
Subject: Materials
Keywords: alkali-metal promotion, COX free H2, MoN2 catalyst, NH3 cracking, solgel method of preparation
Ammonia (NH3), which has a 17.7 wt% gravimetric hydrogen density, has been considered as a potential hydrogen storage material. This study looked at the thermocatalytic decomposition of NH3 using a bulk Mo2N catalyst that was boosted by alkali metals (AM: 5 wt% Li, K, Cs). The K-Mo2N catalyst outperformed all other catalysts in this experiment in terms of catalytic performance. At 6000 h−1 GHSV, 100% conversion of NH3 was accomplished using the K-Mo2N, Cs-Mo2N, and Mo2N catalysts. However, when compared to other catalysts, K-Mo2N had the highest activity, or 80% NH3 conversion, at a lower temperature, or 550 °C. The catalytic activity exhibited the following trend for the rate of hydrogen production per unit surface area: K-Mo2N > Cs-Mo2N > Li-Mo2N > Mo2N. Up to 20 h of testing the K-Mo2N catalyst at 600 °C revealed no considerable deactivation.
2811. LAPSE:2023.36645
A Comprehensive Model for Evaluating Titanium Industry Security in China
September 20, 2023 (v1)
Subject: Environment
Keywords: entropy weight-TOPSIS, grey correlation analysis, security system, Sustainability, titanium industry chain
Currently, China is the largest consumer of titanium (Ti), yet the development of its Ti industry is limited by numerous factors, such as industrial structure imbalance. This study aimed to evaluate the security of China’s Ti industry from 2010 to 2020, seeking to identify relevant issues and propose policy strategies. Firstly, a comprehensive evaluation system for Ti industry security was established, encompassing aspects of availability, economics, and sustainability. Secondly, the entropy weight technique for order preference by similarity to an ideal solution (TOPSIS) combination method and gray correlation method were employed to assess the safety level of China’s Ti industry chain in each year from 2010 to 2020. Additionally, the coupling degree and sensitivity were used to analyze the dimension layers and index system to determine those that negatively impact the safety level of the Ti industry chain. The analysis results reveal that the economic level exerts a significant influ... [more]
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