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Coating Composites Based on Polyurea Elastomers with Increased Fire Resistance and Their Use as Roofing Systems
Wojciech Dukarski, Iwona Rykowska, Piotr Krzyżanowski, Joanna Paciorek-Sadowska, Marek Isbrandt
September 21, 2023 (v1)
Subject: Materials
Keywords: cone calorimetry, flame retardancy, polyurea, tensile strength, thermal properties
This paper presents the results of tests on elastomer coatings based on polyurea−polyurethane formulation with increased fire parameters. Coatings modified with flame retardants: bis(phenylphosphate) resorcinol (RDP), trischloropropyl phosphate (TCPP), and aluminum hydroxide (ATH) were tested. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA/DTG) were used to investigate the structure and thermal stability. The effectiveness of resorcinol bis(phenylphosphate) (RDP), tris chloropropyl phosphate (TCPP), and aluminum hydroxide (ATH) on heat release rate (HRR), smoke release rate (RSR), and oxygen consumption was evaluated using cone calorimetry. The cone calorimetry results were correlated with the mechanical properties of the coatings. The cone calorimetry analysis showed suitable organophosphorus flame retardant (FR) performance, significantly decreasing HRR and oxygen consumption. Additionally, 15% TCPP caused a reduction of HRR by over 50%, obtaining... [more]
Combining α-Al2O3 Packing Material and a ZnO Nanocatalyst in an Ozonized Bubble Column Reactor to Increase the Phenol Degradation from Wastewater
Adnan K. Majhool, Khalid A. Sukkar, May A. Alsaffar
September 21, 2023 (v1)
Subject: Materials
Keywords: multiphase reactor, ozone gas, phenol removal, reaction mechanism, removal efficiency
The ozonation reaction in a bubble column reactor (BCR) has been widely used in the removal of phenol from wastewater, but the phenol removal efficiency in this type of reactor is limited because of low ozone solubility and reactivity in the system. In the present study, the phenol degradation in the BCR was enhanced by using α-Al2O3 as a packing material and a ZnO nanocatalyst. The reactor diameter and height were 8 cm and 180 cm, respectively. The gas distributor was designed to include 52 holes of a 0.5 mm diameter. Also, the gas holdup, pressure drop, and bubble size were measured as a function of the superficial gas velocity (i.e., 0.5, 1, 1.5, 2, 2.5, and 3 cm/s). The evaluation of the hydrodynamic parameters provided a deeper understanding of the ozonation process through which to select the optimal operating parameters in the reactor. It was found that the best superficial gas velocity was 2.5 cm/s. A complete (100%) phenol removal was achieved for phenol concentrations of 15,... [more]
Analysis of Hydrothermal Ageing on Mechanical Performances of Fibre Metal Laminates
Costanzo Bellini, Vittorio Di Cocco, Francesco Iacoviello, Larisa Patricia Mocanu, Gianluca Parodo, Luca Sorrentino, Sandro Turchetta
September 21, 2023 (v1)
Subject: Materials
Keywords: end-notched flexure test, fibre metal laminates, hydrothermal ageing
Fibre Metal Laminates (FMLs) are very interesting materials due to their light weight coupled with their high stiffness, high fatigue resistance, and high damage tolerance. However, the presence of the polymeric matrix in the composite layers and of polymeric adhesive at the metal/composite interface can constitute an Achille’s heel for this class of materials, especially when exposed to a hot environment or water. Therefore, in the present article, aluminium/carbon fibre FML specimens were produced, aged by considering different hydrothermal conditions, and then, subjected to mechanical testing. The End-Notched Flexure (ENF) test was considered for this activity. It was found that the first ageing stage, consisting of submersion in saltwater, was very detrimental to the specimens, while the second stage, composed of high and low temperature cycles, showed an increase in the maximum load, probably due to a post-curing effect of the resin during the higher temperatures of the ageing cyc... [more]
Sequential Processing Using Supercritical Carbon Dioxide and High-Intensity Ultrasound in Sunflower Protein Flour Production: Nutritional Value, Microstructure, and Technological Functionality
Mariana Pacífico dos Santos Friolli, Eric Keven Silva, Janaíne Chaves, Marcos Fellipe da Silva, Rosana Goldbeck, Fabiana Andrea Barrera Galland, Maria Teresa Bertoldo Pacheco
September 21, 2023 (v1)
Subject: Materials
Keywords: food technology, innovative technologies, plant protein, plant-based ingredient, sunflower seed
Sunflowers are among the world’s most widely cultivated oilseeds with an interesting nutritional composition. A biomass composed mainly of carbohydrates, fibers, and proteins is generated from sunflower oil production. In this context, the objective of this study was to investigate the application of emerging technologies to sunflower biomass to obtain an edible protein-rich flour with the potential to be exploited in the food industry. The effects of the optimized conditions for the sequential processing of sunflower meal using supercritical carbon dioxide (SCO2) and high-intensity ultrasound (HIUS) were investigated. The protein structure was preserved even after the application of HIUS to the flour as verified through differential scanning calorimetry (DSC) and the electrophoresis curves. The fact that the HIUS treatment did not modify the protein structure demonstrates that this emerging technology could be incorporated into the processing chain of this new food ingredient (sunflow... [more]
Role of Biosynthesized Silver Nanoparticles with Trigonella foenum-graecum Seeds in Wastewater Treatment
Manal A. Awad, Promy Virk, Awatif A. Hendi, Khalid Mustafa Ortashi, Najla AlMasoud, Taghrid S. Alomar
September 21, 2023 (v1)
Subject: Materials
Keywords: green synthesis, photo degradation, sewage effluent, silver nanoparticles, Trigonella foenum-graecum seed, wastewater treatment
As the human population continues to escalate, its requirement for clean water is also increasing. This has resulted in an increased dependency on wastewater effluent to maintain the base flow of urban streams, especially in water-stressed regions. The present study reports the synthesis of AgNPs with green credentials using an aqueous extract of Trigonella foenum-graecum seeds. The observance of surface plasmon resonance (SPR) with UV−Vis spectrophotometry confirmed the presence of spherical/oblong particles with a mean diameter of 43.8 nm and low polydispersity index (PDI) of 0.391 measured by transmission electron microscopy (TEM) and DLS (dynamic light scattering) technique, respectively. The elemental map of AgNPs was demonstrated with energy-dispersive spectroscopy (EDS) and the constituent functional groups were identified by the FTIR spectra, which were similar to the bulk seed extract with a slight shift in the pattern. The emission spectrum of nanoparticles was recorded for t... [more]
Effects of Process Parameters on the Microstructure and Mechanical Properties of Large PE Pipe via Polymer Melt Jetting Stacking
Shenglin Wu, Wei Zhang, Yafeng Zhu
September 21, 2023 (v1)
Subject: Materials
Keywords: impact strength, large diameter pipe, microstructure, polymer melt jetting and stacking, tensile strength
The conventional methods for producing large-diameter pipes, such as extrusion and winding fusion welding, suffer from various drawbacks including difficulties in forming, complex molds, and high costs. Moreover, the flexibility and production efficiency of traditional manufacturing processes are relatively low. To address these challenges, this study proposes a new manufacturing process for polymer melt jetting and stacking based on fused deposition modeling (FDM) and rolling forming principles. This innovative approach aims to overcome the limitations of conventional methods and improve the flexibility and production efficiency in large-diameter pipe manufacturing. In the polymer melt jetting and stacking process, a plastic melt with a specific temperature and pressure is extruded by an extruder. The melt is then injected through the nozzle embedded in the previous layer of the pipe blank. By utilizing the localized rolling action of the forming device and adjusting the diameter usin... [more]
Gelatin and Gelatin/Rice Starch Coatings Affect Differently Fresh-Cut Potatoes and Colocasia Slices
Anastasia Bari, Persephoni Giannouli
September 21, 2023 (v1)
Subject: Materials
Keywords: Colocasia, color, gelatin, potato, rice starch, texture
Traditional food packaging materials maintain food quality and safety during storage, but they cause significant environmental pollution. For this reason, there has been an increased demand in designing packaging materials from biodegradable ingredients such as edible proteins and polysaccharides. In the current study, biodegradable coatings from gelatin (Gel) or gelatin−rice starch (Gel-RS) mixtures were applied to fresh-cut Colocasia (Colocasia esculenta) and potato (Solanum tuberosum) samples, and main quality properties such as weight loss, firmness, breaking force, and color were evaluated during storage for seven days at 5 °C. Gel-coated potato samples kept moisture at higher levels compared to untreated samples or Gel-RS-coated samples (weight loss 41.40 ± 3.33%), while no differences in weight loss were observed for all fresh-cut Colocasia samples. Furthermore, the gelatin−rice starch coating increased the breaking force (1181.40 ± 159.73) and hardness (1609.6 ± 76.79) of fresh... [more]
Perovskite Nano-Powder and Nano-Film Catalysts in Mineralization of Aqueous Organic Contaminants through Solar Simulated Radiation
Tamara Zorba, Heba Nassar, Muath H. S. Helal, Jeheon Song, Tae Woo Kim, Shehdeh Jodeh, Hikmat S. Hilal
September 21, 2023 (v1)
Subject: Materials
Keywords: batch and continuous flow reactions, methylene blue photodegradation, MnTiO3, solar simulated radiation, ZnTiO3
Water contamination with various contaminants, including organic species, is a global concern. Reclamation through safe, economic and technically feasible methods is imperative. Two perovskites, zinc titanate (ZnTiO3) and manganese titanate (MnTiO3), mixed with TiO2 phases, were prepared as nano-powders and nano-films. The materials were characterized and used as catalysts in photodegradation of aqueous methylene blue, a hazardous model contaminant, using solar simulated radiation. The effects of various reaction conditions on the photodegradation were examined. The kinetics indicated the suitability of using the process at various contaminant concentrations and catalyst loadings. Both powder and film catalysts completely removed the contaminant in less than 6 h. Powder and film forms of the MnTiO3 mixture were more efficient than their ZnTiO3 counterparts. In both perovskite mixtures, the films exhibited higher catalytic efficiency than the powders. The film materials exhibited high c... [more]
Preparation and Characterization of Polyhedron Mn(III) Oxide/-β-Mn(IV) Oxide/Poly-o-chloroaniline Porous Nanocomposite for Electroanalytical Photon Detection
Mohamed Rabia, Asmaa M. Elsayed, Maha Abdallah Alnuwaiser
September 21, 2023 (v1)
Subject: Materials
Keywords: Mn2O3/β-MnO2, nanocomposite, optoelectronic, poly-o-chloroaniline
Poly-o-chloroaniline (POCA) and Mn2O3/β-MnO2/POCA porous nanocomposite are both synthesized using oxidative polymerization, with K2S2O8 and KMnO4 as oxidants, respectively. The materials are characterized to confirm their optical, morphological, crystalline, chemical, and elemental properties. The nanocomposite exhibits superior optical properties compared to POCA. The promising optical characteristics make the nanocomposite an attractive candidate for light-sensing applications. Through electrical estimation, the nanocomposite photodetector displays the highest sensitivity between 340 and 440 nm, with Jph (current density) of 0.14 and 0.13 mA cm−2, correspondingly, and an estimated photon number of 7.461021 and 6.93 × 1021 photons/s, respectively. At 340 and 440 nm, the calculated photoresponsivity (R) values are 0.73 and 0.64 mA W−1, respectively, while the estimated detectivity (D) values are 1.64 × 108 and 1.45 × 108 Jones, respectively. These promising results indicate that the fa... [more]
Pulsed Laser Deposition of Carbon-Based Materials: A Focused Review of Methods and Results
Rosalba Gaudiuso
September 21, 2023 (v1)
Subject: Materials
Keywords: carbon-atom wire (CAW), carbyne, diamond-like carbon (DLC), graphene, pulsed laser deposition (PLD)
Pulsed Laser Deposition (PLD) is a highly flexible experimental methodology for the growth of thin films of a broad variety of materials, based on the generation of laser-induced plasmas (LIP) with material ablated from a solid target and on the transfer of the ablated material to a substrate. This review is focused on carbon-based materials—specifically, diamond-like carbon (DLC), graphene and carbyne—and will both discuss the influence of the most critical experimental parameters on the obtained materials and present the experimental developments proposed in the recent literature to tailor the properties of the deposited films and optimize the standard PLD technique for production of various carbon-based materials.
Fabrication of a Charge-Conversion Polymer—Liposome for Enhancing Endosomal Escape of Drug Delivery System for α−Mangostin
Trang Thi Kieu Phan, Hoang Huy Nguyen, Xuan Thi Nguyen, Tung Van Nguyen, Linh Anh Duong, Linh Phuong Nguyen, Uyen Thu Pham, Hong Nhung Le, Toan Quoc Tran, Duong Thanh Nguyen, Dung Thuy Nguyen Pham
September 20, 2023 (v1)
Subject: Materials
Keywords: charge-conversion polymer, DDS, liposome, α–mangostin
α−Mangostin, which is a natural xanthone compound, inhibits the metastasis and survival of various cancer cell types. However, its therapeutic effectiveness is limited by low water solubility and very poor absorption. There are several studies that developed the drug delivery system for α−mangostin, but they are still a remaining challenge. Drug delivery techniques are severely hampered by the breakdown of nanoparticles inside endosomes. The abrasive chemical environment in these compartments causes both the nanoparticles and the encapsulated α−mangostin to degrade throughout the course of the voyage. Intracellular defenses against external materials refer to this collective mechanism. A pH-responsive liposome named PAsp(DET-Cit)−Toc, made of lipids and a charge-conversion polymer (CCP), has been created for the targeted transport of α−mangostin in order to avoid this deteriorative outcome. The average hydrodynamic size of CCP−liposome particles is 98.59 ± 5.1 nm with a PDI of 0.098 ±... [more]
The Thermodynamic Characterizations of Hydrogen Production from Catalyst-Enhanced Steam Reforming of Bio-Oil over Granulated Blast Furnace Slag as Heat Carrier
Zhijun Ding, Yang Liu, Xin Yao, Yuekai Xue, Chenxiao Li, Zhihui Li, Shuhuan Wang, Jianwei Wu
September 20, 2023 (v1)
Subject: Materials
Keywords: catalyst-enhanced steam reforming, granulated BF slag, heat recovery, thermodynamic analysis
To promote the efficiency of waste heat recovery from granulated blast furnace (BF) slag, a novel method of catalyst-enhanced steam reforming of bio-oil to recover heat from slag is proposed. CaO is utilized as a superior catalyst for the process of catalyst-enhanced steam reforming. The thermodynamic production of the catalyst-enhanced steam reforming of bio-oil in granulated BF slag is obtained using HSC 6.0 software. The optimal conditions are mainly assessed according to the hydrogen yield, hydrogen concentration and carbon production. Through the thermodynamic production and industrial application, the temperature of 608 °C, S/C of eight and pressure of 1 bar are found as the optimal conditions. At the optimal conditions, the hydrogen yield, hydrogen concentration and carbon production are 95.25%, 76.89% and 0.28 mol/kg, respectively. Taking the temperature of 625 °C, S/C of eight and pressure of 1 bar as an example, the catalyst could improve the hydrogen yield and hydrogen conce... [more]
Coal Pillar Size Determination and Surrounding Rock Control for Gob-Side Entry Driving in Deep Soft Coal Seams
Zaisheng Jiang, Wenke Guo, Shengrong Xie
September 20, 2023 (v1)
Subject: Materials
Keywords: deep mine, gob-side entry driving, joint control, small coal pillar, soft coal seam
In response to the large-scale instability failure problem of designing coal pillars and support systems for gob-side entry driving (GSED) in high-stress soft coal seams in deep mines, the main difficulties in the surrounding rock control of GSED were analyzed. The relationship between the position of the main roof breaking line, together with the width of the limit equilibrium zone and a reasonable size for the coal pillar, were quantified through theoretical calculations. The theoretical calculations showed that the maximum and minimum widths of the coal pillar are 8.40 m and 5.47 m, respectively. A numerical simulation was used to study the distribution characteristics and evolution laws of deviatoric stress and plastic failure fields in the GSED surrounding rock under different coal pillar sizes. Theoretical analysis, numerical simulation, and engineering practice were comprehensively applied to determine a reasonable size for narrow coal pillars for GSED in deep soft coal seams, w... [more]
Pore Structure Change in the Continental Shale Oil Reservoir and Its Main Influencing Factors: A Case Study of the Chang 7 Member in the Ordos Basin
Xin He, Shijia Chen, Cong Hu, Haifeng Zhang, Feisheng Mou, Linfeng Dai, Yifan Lu, Xiaoyan Fu, Meimei Han
September 20, 2023 (v1)
Subject: Materials
Keywords: Chang 7 member, influencing factors, oil content, Ordos Basin, reservoir, shale oil
Shale oil in the Chang 7 member is the main target for further exploration in the Ordos Basin. However, the lack of research on the characteristics of the Chang 7 member’s mudstone and shale reservoir has seriously affected the next stage of exploration for shale oil in the Chang 7 member. This study analyzed in detail the changes in the pore structure of different types of reservoirs and their influencing factors in detail through experiments such as gas adsorption, nuclear magnetic resonance, and high-pressure mercury intrusion. The results showed that black shale is mainly composed of micropores, with a micropore ratio of up to 79.88%. Dark mudstone and silty mudstone are mainly composed of mesopores, with a mesopore ratio greater than 30%. Argillaceous sandstone is mainly composed of large pores, accounting for 78.57%. From black shale to muddy sandstone, the proportion of micropores decreases, while the proportion of macropores increases. The micropore volume is mainly controlled... [more]
Study on Mechanism of MSWI Fly Ash Solidified by Multiple Solid Waste-Based Cementitious Material Using the Rietveld Method
Xiaoli Wang, Pingfeng Fu, Wei Deng, JinJin Shi, Miao Xu
September 20, 2023 (v1)
Subject: Materials
Keywords: cementitious material, heavy metals, MSWI fly ash, multiple solid waste, Rietveld method, solidification, X-ray diffraction
A novel multiple solid waste-based cementitious material (MSWCM) was developed to immobilize municipal solid waste incineration (MSWI) fly ash. The compressive strength of MSWCM with different ratios of MSWI fly ash reached the standard requirements after curing for 28 days. X-ray powder diffraction (XRD) in combination with the Rietveld method was employed to investigate the content and phase transformation of hydration products. The main hydration products of pure MSWCM paste were C-S-H, hydroxyapatite, ettringite and C-A-S-H. With increases in curing time, the content of ettringite and C-A-S-H increased significantly. The main hydration products of MSWCM paste with MSWI fly ash were C-S-H and Friedel’s salt. The contents increased markedly with increased curing time from 21.8% to 28.0% and from 8.53% to 16.7%, respectively. Additionally, a small amount of PbHPO4 (0.51−0.96%) and lead phosphate Pb3(PO4)2 (0.14−0.51%) were detected, indicating that phosphate had an effective curing ef... [more]
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
María Fernanda Munguía-Quintero, Miguel Ángel Vega-Hernández, Alberto Rosas-Aburto, Martín Guillermo Hernández-Luna, Simón López-Ramírez, José Fernando Barragán-Aroche, Eduardo Vivaldo-Lima
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]
Plasma-Arc-Flow Technology for Sustainable Treatment of High-Impact Fluid Waste: A Graphene-Based Material for Industrial-Wastewater Purification
Carmine Mongiello, Mohammad Ghoreishi, Vinod Kumar Sharma, Liberato Verdoliva, Sabato Aprea, Paolo Venturini, Gianluca Pesce
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]
Deformation Characteristics of Asymmetric Gradient Extrusion in Preparing Ultra-Fine-Grained Bulk Materials
Junkai Fan, Jikang Li, Wei Liu, Chengpeng Wang
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]
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
Jiaqi Li, Liang Xiao, Hui Xi, Ruiqiang Chi, Hucheng Wen, Wenjing Zhang
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]
Physical and Chemical Phenomena during the Production of Hydrogen in the Microwave Discharge Generated in Liquid Hydrocarbons with the Barbotage of Various Gases
Timur S. Batukaev, Igor V. Bilera, Galina V. Krashevskaya, Yuri A. Lebedev
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.
Cause Analysis of Condensed Water Induced Bulging in High-Pressure Steam Tee Joints of a Pyrolyzer
Weiqi Lian, Zhiwei Sun, Yunrong Lyu, Zhihong Duan
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]
Ammonia Decomposition over Alkali Metal (Li, K, Cs)-Promoted Bulk Mo2N Catalyst
Hisham S. Bamufleh, Sharif F. Zaman
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.
Research and Development of Anti-High-Pressure Sealing Material and Its Bonding Performance
Shigang Hao, Xianzhong Li, Tao Wu, Weilong Zhou, Jinhao Zhang
September 20, 2023 (v1)
Subject: Materials
Keywords: bond performance, fiber materials, fractal dimension, high-pressure sealing materials, hydraulic fracturing
To solve the problem of the field application of downhole hydraulic fracturing technology due to the difficulty in sealing holes, this study analyzes the influence of special cement, expansion agents, stabilizers, and fiber material on basic properties, such as the setting time, fluidity, and compressive strength of high-pressure sealing materials through systematic tests based on a summary of conventional sealing materials. It was determined that with 20−30% special cement and 4% expansion agent added, and a fiber material length of 8 mm and volume of 1%, the high-pressure sealing material had high fluidity and a large expansion rate, demonstrating early strength. The bond performance of the high-pressure sealing material was tested through the variable-angle shear test. The relationship between the fractal dimension of the coal-rock mass around the borehole and the bond performance of the high-pressure sealing material was also explored.
Optimization of Abrasive Water Jet Machining Process Parameters on Onyx Composite Followed by Additive Manufacturing
Dharmalingam Ganesan, Sachin Salunkhe, Deepak Panghal, Arun Prasad Murali, Sivakumar Mahalingam, Hariprasad Tarigonda, Sharad Ramdas Gawade, Hussein Mohamed Abdel-Moneam Hussein
September 20, 2023 (v1)
Subject: Materials
Keywords: abrasive water jet machining, delamination, onyx composite, surface roughness, Taguchi analysis
Fiber-reinforced additive manufacturing components have been used in various industrial applications in recent years, including in the production of aerospace, automobile, and biomedical components. Compared to conventional methods, additive manufacturing (AM) methods can be used to obtainin lighter parts with superior mechanical properties with lower setup costs and the ability to design more complex parts. Additionally, the fabrication of onyx composites using the conventional method can result in delamination, which is a significant issue during composite machining. To address these shortcomings, the fabrication of onyx composites via additive manufacturing with the Mark forged 3D-composite printer was considered. Machinability tests were conducted using abrasive water jet machining (AWJM) with various drilling diameters, traverse speeds, and abrasive mass flow rates. These parameters were optimized using Taguchi analysis and then validated using the Genetic algorithm (GA) and the M... [more]
Concurrent Biocatalytic Oxidation of 5-Hydroxymethylfurfural into 2,5-Furandicarboxylic Acid by Merging Galactose Oxidase with Whole Cells
Fan-Feng Zhu, Jian-Peng Wang, Min-Hua Zong, Zhao-Juan Zheng, Ning Li
September 20, 2023 (v1)
Subject: Materials
Keywords: aldehyde dehydrogenases, biobased chemicals, biocatalysis, bioplastics, cascade oxidation, oxidases
2,5-Furandicarboxylic acid (FDCA) is an important monomer for manufacturing biobased plastics. Biocatalysis has been recognized as a sustainable tool in organic synthesis. To date, the efficiencies of most biocatalytic processes toward FDCA remain low. So, it is highly desired to develop efficient processes. In this work, a biocatalytic route toward FDCA was developed by integrating a cell-free extract of galactose oxidase variant M3−5 with a whole-cell biocatalyst harboring NAD+-dependent vanillin dehydrogenases and NADH oxidase, starting from 5-hydroxymethylfurfural. FDCA was produced in a concurrent mode with >90% yields within 36 h at 20 mM substrate concentration. In addition, biocatalytic synthesis of FDCA was performed on a preparative scale, with 78% isolated yield. The present work may lay the foundation for sustainable production of FDCA.
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