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The removal effectiveness of the M0F-808 material for organic chloride in a plastic cracking oil was studied in light of its excellent adsorption properties. The M0F-808 materials was prepared, and then the Zrx: Fey@M0F-808 materials with different doping ratios were prepared by using a hydrothermal synthesis method. Four typical organic chlorides in the plastic cracking oil were selected to prepare a model oil, and the optimal x/y ratio was determined to be 1: 0. 67 according to the removal rate of organic chlorides in the model oil. The optimal reaction conditions and reuse performance of adsorption dechlorination experiments were determined, and the corresponding adsorption mechanism was investigated. The results indicated that the as-prepared Zr: Fe067@M0F-08 adsorption material exhibited has good structure and stability. The removal rate of chloride in the model oil was as high as 97. 66 % at an adsorption temperature of 50 °C, an adsorption time of 2 h, and an agent/oil mass ratio of 1/40. The dechlorination rate remained to be above 85 % after repeatedly using the adsorbent for 6 times. The adsorption process conformed to a pseudo-second-order kinetic model, belonging to a spontaneous chemisorption process. [ABSTRACT FROM AUTHOR]

The effects of different hot air speeds and temperatures on the drying characteristics of half-ripe rice paper were investigated by hot air convection drying experiments. The thin-layer drying experiments were carried out at three different combinations of air speeds of 1.97 m/s, 3.00 m/s, and 3.90 m/s and temperatures of 85 °C, 100 °C and 115 °C. The results show that among the 10 drying kinetic models selected, the Modified Page model is the most suitable model to describe the drying characteristics of the thin layer of half-ripe rice paper; the whole drying process exists obvious ascending, constant and descending processes; the effective moisture diffusion coefficient of half-ripe rice paper is in the range of 1.52656 × 10−9 m2/s–3.15816 × 10−9 m2/s, whose size increases with the increase of the hot wind speed and temperature. Its magnitude increases with the increase of wind speed and temperature; the drying activation energy of half-ripe rice paper is 6.55 kJ/mol calculated by Arrhenius equation. [ABSTRACT FROM AUTHOR]

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Women's participation in the tourism workforce is growing intensely in response to Saudi Vision 2030. Notwithstanding this, Saudi women still have limited access to senior management positions. This study explores the barriers that Saudi women face to reach top managerial positions in the tourism industry and explores how Saudi women could crack the glass ceiling. For these reasons, this study undertook a phenomenological approach using in-depth interviews with Saudi women who were able to reach senior management. The purpose of the interviews is to explore their lived experience and their accessibility to senior management positions. The results of a thematic analysis showed that there were four overlapped barriers for the glass ceiling among Saudi women: cultural and social barriers, regulatory barriers, organizational barriers, and personal barriers. These main barriers have sub-barriers that contribute to the glass ceiling and prevent many women from reaching senior positions. This study shows that overcoming these barriers, particularly cultural and social barriers, could help Saudi women to crack the glass ceiling and achieve their dream of leadership. This study discusses the implications for policy makers, academics, and practitioners on the effective contribution of Saudi women to the tourism labor market, which contributes to sustainable tourism development and, ultimately, to Saudi Vision 2030. [ABSTRACT FROM AUTHOR]

Hydrogen-Bonded organic frameworks (HOFs) are a type of emerging porous materials. At present, little research has been conducted on their solution state. This work demonstrates that HOFs fragment into small particles while maintaining their original assemblies upon dispersing in solvents, as confirmed by Cryo-electron microscopy coupled with 3D electron diffraction technology. 1D and 2D-Nuclear Magnetic Resonance (NMR) and zeta potential analyses indicate the HOF-based colloid solution and the isolated molecular solution have significant differences in intermolecular interactions and aggregation behavior. Such unique solution processibility allows for fabricating diverse continuous HOF membranes with high crystallinity and porosity through solution-casting approach on various substrates. Among them, HOF-BTB@AAO membranes show high C3H6 permeance (1.979 × 10−7 mol·s−1·m−2·Pa−1) and excellent separation performance toward C3H6 and C3H8 (SF = 14). This continuous membrane presents a green, low-cost, and efficient separation technology with potential applications in petroleum cracking and purification. Hydrogen-bonded organic frameworks (HOFs) attract increasing attention as porous materials. Despite the widely studied solid-state properties, little research has been done on the solution state. Here, the authors demonstrate that HOFs fragment into small particles while maintaining their original assemblies upon dispersing in solvents. [ABSTRACT FROM AUTHOR]

The research progress of heavy oil catalytic cracking technology at home and abroad is summarized from three aspects: the research survey of reaction mechanism of heavy oil catalytic cracking, the analysis and comparison of molecular sieve catalytic materials for heavy oil catalytic cracking, the technical characteristics and industrial application of different heavy oil catalytic cracking processes. Firstly, modified molecular sieve catalyst materials, small-crystal molecular sieves, hierarchical pore molecular sieves have become hot spots in current research and application, so as to strengthen the hydrothermal stability of catalyst, the intracrystalline diffusion and the graded cracking of heavy oil macromolecules in the hierarchical pores of the heavy oil catalytic cracking catalyst; secondly, based on the research of the carbonium ion mechanism and the free radical mechanism of the catalytic cracking reaction and the like, the reaction severity of heavy oil catalytic cracking technologies such as DCC, CPP, HCC, RTC and HSFCC is continuously improved, and in order to match the optimal reaction environment for different feeds, new reactor or multi-reactor combination technology has become the main direction of process technology research, which has achieved the purpose of improving the yield and selectivity of light olefins. [ABSTRACT FROM AUTHOR]

Introduction: The occurrence of mixed fracture mechanisms in mechanical elements is frequent, due to the action of multiple factors that intervene during their design, manufacturing and operation. Objective: To establish the causes of failures in tripod columns on trucks, based on the characterization of the base metal and the welded joints in the failure region. Materials and Methods: Visual inspection of the failures, chemical and microstructural characterization by optical microscopy of the columns, as well as tensible test of the base material were carried out. Results and Discussion: The integrated visual inspection analysis and the results of chemical and metallographic characterization reveal that the material of the columns is not recommended for welded structures and that measures such as preheating and thermal treatment after welding were not taken. Due to the characteristics of the steel and the location of the detected cracks, they may be associated with diffusible hydrogen cracking. Conclusions: The failure of the columns was the result of a combination of several factors, highlighting design and manufacturing errors in the selection of a non-recommended material and the non-execution of attenuation measures during the execution of the welding, also linked to factors such as, possible overloads or improper operation of the equipment. [ABSTRACT FROM AUTHOR]

Conducting a study on this topic becomes relevant due to the great importance of the safety of critical infrastructure facilities and the presence of operational defects in equipment elements and pipelines, which poses serious threats, including the possibility of equipment destruction and negative environmental impact. The purpose of this work is to study the possibility of using the diffraction-time technique of ultrasonic non-destructive testing together with a deep convolutional neural network to accurately determine the numerical value of the height of an operational crack. The methods used include the analytical method, classification method, functional method, statistical method, synthesis method, and others. The study found that an automated approach to measuring crack height, based on diffraction signals and the use of neural networks, significantly improved the quality and accuracy of non-destructive testing. Ultrasonic testing is one of the most common inspection methods for detecting service cracks and is considered to be the most effective. It allows for reliable detection of defects and determination of their size without destroying the product. The results of the study emphasize the high potential and efficiency of the method in analysing the data obtained and provide confirmation of its applicability for determining the condition of objects during ultrasonic inspection. The paper emphasizes that these technologies are particularly important and effective. It is noted that their widespread use in various industries, such as medicine, aviation, and machine learning, demonstrates their power in solving complex problems. The practical significance of the work lies in the development of advanced approaches that provide new insights and methods to improve the efficiency of analysing the results, which can be applied in industry to improve the quality of control and reliability of technical facilities. [ABSTRACT FROM AUTHOR]

• The effect of CNTs on the thermal expansion coefficient (CTE) of FSC at early age was investigated. • A time-varying model of FSC at early age CTE was developed based on maturity theory. • The time-varying CTE can reflect the actual thermal cracking situation of FSC. • The addition of 0.1 wt% CNTs can reduce the early CTE of FSC and improve its crack resistance. Temperature stresses are a major cause of thermal cracking in face slab concrete (FSC) at an early age. Time-varying coefficient of thermal expansion (CTE) can reflect the real thermal cracking of FSC. Carbon nanotubes (CNTs) can improve the mechanical properties of concrete, but its thermal cracking performance is rarely reported. In this study, CTE of FSC at an early age was investigated based on the maturity theory. The mechanism of CNTs on the CTE of FSC at early age was revealed, and a time-varying model for CTE at early age was developed. The results showed that CNTs can effectively reduce the CTE of FSC at an early age and can significantly improve the cracking resistance of FSC at early age. [ABSTRACT FROM AUTHOR]

Compared with conventional pyrolysis, microwave pyrolysis has superior heat transfer performance and promotes the decomposition of organic matter. The paper focuses on the harmless treatment and resource utilization of pharmaceutical sludge (PS) by microwave heating and conventional heating methods. The experimental results showed that the conventional pyrolysis gas is dominated by CO 2 , CO and H 2. For microwave pyrolysis gas, the "microwave effect" promoted secondary cracking of volatile fractions and increases the content of CH 4 , C x H y , H 2 and CO through condensation, aromatization, and dehydrogenation. Conventional pyrolysis oils contained the highest percentage of oxygenated compounds. However, high-temperature microwave radiation accelerated the cleavage of polar oxygenated molecular bonds and long-chain hydrocarbons, thereby increasing the aromatics content of pyrolysis oils. The solid residues obtained from microwave pyrolysis is highly graphitized and porous, with a surface area of 146.2 m2/g. Furthermore, the solid residue was rich in pyridine-N and pyrrole-N that could be utilized for adsorption and catalysis. The MA-600 removes up to 99% of tetracycline (TC) in 6 h. It was also found that the adsorption process of TC by the two pyrolysis residues was consistent with the proposed secondary and Freundlich models. [Display omitted] • Microwave pyrolysis oil has a smaller carbon number. • Hot spots and dehydrogenation are key factors in increasing C x H y yields. • Microwave pyrolysis residue surfaces are dominated by pyrrole nitrogen. • Porosity of microwave pyrolysis residues facilitates TC adsorption. [ABSTRACT FROM AUTHOR]

Several studies conducted at industrial sites have documented the infiltration of dense non-aqueous phase liquids (DNAPLs) into clay layers, a phenomenon potentially influenced by the coexistence of chemicals like surfactants in some common pollutants. Bentonite (Ben), monochlorobenzene (MCB), and Tween 80 (T80) were selected as reference components to investigate the influences of nonionic surfactants on DNAPLs migration in clays. Results showed that T80 promotes MCB dissolution and encourages MCB adsorption on Ben. This process reduces the hydrophilicity of Ben, resulting in water loss and shrinkage, which creates cracks and facilitates the migration of MCB within the clay. Tw80 notably enhances MCB solubility, as indicated by a molar solubilization ratio of 7.80. The MCB adsorption on Ben (Q MCB) displays a linear increase with raising the T80 adsorption on Ben (Q T80), especially when Q T80 are below the thresholds, e.g., 408.4 mg/g at pH 3 and 339.3 mg/g at pH 7; however, Q MCB is decreased with increasing adsorbed T80 further. The average fracture ratio, crack length, and crack width of cracked samples in the cracking experiments were 0.794%, 11.29 mm, and 0.209 mm, respectively. The findings here contribute to understanding the role of surfactants in VOC transport in contaminated sites. [Display omitted] • Tween 80 and MCB mutually enhance their adsorption onto bentonite. • Dissolved and adsorbed T80 has a competitive effect on MCB adsorption. • Upon Tween 80 or MCB adsorption, the hydrophilicity of bentonite is reduced. • Tween 80 induce cracks in bentonite to facilitate the migration of MCB. [ABSTRACT FROM AUTHOR]

In the present study, we pyrolyzed a waste tire at various temperatures under an N 2 atmosphere and a water environment in an autoclave reactor to investigate the effect of water on tire degradation. The analysis involved a comparison of product distribution, char properties, oil composition, and the behavior of heteroatom elements (especially oxygen, nitrogen, and sulfur) under different atmospheres. Elemental analysis, functional-group identification, and chemical state analysis of sulfur were performed for chars. In addition, the chemical composition, elemental composition, and molecular weight of the produced oils were evaluated. The heavy fraction of oils, not detectable by gas chromatography-mass spectrometry (GC-MS), was analyzed through Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The findings revealed that high temperatures promoted oil cracking, resulting in the formation of light oils in both pyrolysis and hydrolysis processes. Compared to pyrolysis, hydrolysis generated a higher yield of low molecular–weight oil. Elevated hydrolysis temperatures promoted aromatization, yielding an oil with a low H/C ratio and a high double bond equivalent number. Consequently, the concentration of aromatics in the light fraction of oils generated from the hydrolysis process exceeded that in oils from the pyrolysis process. Temperature exhibited a limited impact on oil composition during the pyrolysis process. Hydrolysis promoted the release of heteroatom-containing compounds at low temperatures. During pyrolysis, nitrogen was gradually released from the solid phase, whereas nitrogen-containing compounds were released early during hydrolysis, with gas-phase nitrogen accounting for more than 50 wt% at 320 °C. A maximum D-limonene yield of 45.58% was obtained at 360 °C within 0 min of hydrolysis, with the potential conversion of D-limonene into aromatics at higher hydrolysis temperatures. These results contribute to the understanding of tire valorization via hydrolysis. [Display omitted] • Higher temperatures can promote the formation of aromatics. • Hydrolysis promote the early release of nitrogen-containing compounds. • Higher hydrolysis temperatures can promote the formation of sulfide. • Temperature has a weak effect on oil composition for pyrolysis process. • Extensive of NxOy, NxOySz, NxSy, Nx and Ox classes formed. [ABSTRACT FROM AUTHOR]

This study quantitatively and fundamentally evaluated the effects of B and Hf on weld solidification cracking susceptibility for 247LC superalloy, and the behavior was compared with that of 247LC's original composition. To this end, the transverse-Varestraint test was performed by measuring the cracking temperature during weld solidification. The solidification brittle temperature range (BTR) values of the Boron (B)- and Hafnium (Hf)-free 247LC alloys were 206 and 172 K, respectively, which were significantly lower than that of the original 247LC alloy (400 K). Contrastingly, the minimum strain for solidification cracking ε min was similar in both alloys. The metallurgical mechanism for the largely reduced BTR (from 400 K to 172 K) was elucidated especially for the Hf-free 247LC alloy, which was highly dependent on its weld mushy zone range (170 K) calculated by non-equilibrium weld solidification. It was attributed to the suppression of carbide (MC + M 23 C 6) formation for Hf-free 247LC (area fraction: 0.15%) as compared with that of 247LC (area fraction: 4.72%) by direct identifying the solidification cracking surfaces. • Solidification cracking susceptibilities of 247LC and Hf,B-free alloys studied. • Brittle temperature range (BTR) reduced from 400 K to 170 K by nonaddition of Hf. • The reduced BTR attributed to suppressed carbide formation. [ABSTRACT FROM AUTHOR]

Recently, sp2-hybridized single-layer SiC, analogous to graphene, has received much attention in nanoelectronics and nanoelectromechanical systems because of its remarkable thermal, electrical, and mechanical properties. However, the unique properties and related applications strongly depend on the growth of a single-crystal and large-area two-dimensional SiC. The majority of synthesized SiC monolayers exhibit a natural polycrystalline structure, comprising single-crystalline grains with diverse sizes and orientations. Moreover, the emergence of structural defects, including cracks and notches, poses challenges that are difficult to overcome during both the fabrication and subsequent processing stages. In this paper, we explore the atomistic details of grain, crack, and notch effect on the mechanical behaviors and fracture mechanisms of single-layer SiC using molecular dynamics simulations. Increasing grain size from 2 nm to 35 nm gradually increases the elastic modulus and fracture strength, which fits well with the inverse Pseudo Hall-Petch relationship. However, an anomalous trend of decreasing as well as increasing fracture strain is observed with the increasing grain size. For polycrystalline SiC with a 2 nm grain size, the elastic modulus and fracture strength are roughly 87% and 41% of those observed in single-crystalline SiC. Notably, when comparing the impact of rectangular crack and circular notch defects, the circular notch exhibited a more pronounced effect in diminishing mechanical behavior under both armchair and zigzag orientational loading. The circular notch produces considerable amorphization around the notch, but the rectangular crack does not show any significant dislocation or amorphization around the crack. The critical stress intensity factor, energy release rate, radial distribution function, and potential energy per atom are calculated to explain all the fracture properties. The effect of temperature and strain rate is also investigated for all the defect-induced samples. Overall, our results provide new insight and understanding of the mechanical behavior and fracture mechanisms of polycrystalline, crack- and notch-induced SiC, and set a standard for making and designing new nanodevices and nanostructures made of SiC. [Display omitted] • Grain, crack, and notch effects on the mechanical behavior of 2D SiC are studied. • The MEAM potential is used to describe the atomistic interactions of monolayer SiC. • 2D SiC shows an inverse pseudo-hall-petch relation with increasing grain size. • Notch creates a higher decrease in mechanical properties than crack defects. • Fracture toughness and energy release rate are estimated to define defect actions. [ABSTRACT FROM AUTHOR]

A major drawback in the application of AlCoCrFeNiCu high-entropy alloy (HEA) coatings is a susceptibility to hot-cracking, which is closely related to a grain boundary segregation due to the low melting point Cu component. Reducing or eliminating the grain boundary segregation of Cu is an effective means of reducing cracking in the HEA coating. In this study, blended and partial pre-alloyed powders were used as feedstock to fabricate the AlCoCrFeNiCu coating. The application of electron beam (EB) cladding to partial pre-alloyed powders, prepared by resistance seam welding (RSEW), resulted in an appreciable reduction of crack density in the coating. This response is attributed to the formation of Ni 3 Al and Al 4 Cu 9 promoted by the relatively low heat generated during the RSEW process. In subsequent EB cladding, nanoscale Me 3 Al (Me = Cu, Ni) replaced the Cu-rich phase at grain boundaries. The hardness and wear resistance of coatings using partially pre-alloyed powders were 17.2 % and 15.8 % higher, respectively, than blended powders. The findings of this study indicate that the use of partial pre-alloyed powders can offer a new effective approach to reducing the hot cracks in EB cladding AlCoCrFeNiCu HEA coatings. [Display omitted] • AlCoCrFeNiCu coatings were fabricated by blended and partial pre-alloyed powders. • Cracks were reduced using partial pre-alloyed powders by electron beam cladding. • Ni 3 Al and Al 4 Cu 9 phases reduced the interdendritic segregation of Cu in RE coatings. • Wear resistance of RE coating was optimal 20.4 % higher than EB coating. [ABSTRACT FROM AUTHOR]

In this study, anodized aluminum oxide (AAO) films were fabricated in situ on the surface of a high-strength and robust 2024 aluminum alloy using step voltage and constant voltage modes, respectively. Our study included examination of the microstructure, thickness, microhardness, and electrochemical characteristics of the AAO films. Cross-sectional morphology analysis revealed that the AAO film produced via the step-voltage approach exhibited remarkable density, uniformity, and good quality. In contrast, conspicuous cracks were observed in the AAO film generated under constant-voltage conditions when applied to the 2024 aluminum alloy substrate. Notably, the microhardness of the AAO film prepared using the step voltage method surpassed that of its constant-voltage counterpart. Specifically, the microhardness of the AAO film produced at 30 V via the step voltage reached 289 HV, whereas the equivalent AAO film produced at a constant voltage of 30 V registered only 174 HV. Furthermore, the self-corrosion potential and polarization resistance of the AAO films created using the step voltage were markedly higher than those achieved using a constant voltage. Specifically, the AAO films produced under step voltage conditions, specifically at 30 V and 60 min, exhibited the highest self-corrosion potential and polarization resistance values of namely −0.52 V and 34,888.6 Ω, respectively. In contrast, AAO films prepared under constant voltage conditions displayed values of −0.61 V and 23,292.0 Ω, respectively. Conducting AC impedance measurements and subsequent fitting calculations, the maximum thickness of the AAO film generated via step voltage and constant voltage methods amounted to 132.43 nm and 106.70 nm, respectively. Overall, the microstructure and corrosion resistance of the AAO film formed on the surface of the 2024 aluminum alloy using the step voltage approach demonstrated that it outperformed that of the AAO layer prepared under constant-voltage conditions. Chinese library classification number:TG178 Document ID:A Article ID. • A new method and new idea for preparing anodic oxide film on aluminum alloy surface were explored. • Anodic oxide film produced using the step voltage approach exhibited a dense and uniform microstructure, forming a strong bond with the 2024 aluminum alloy substrate. • Anodic oxide film prepared the step voltage method exhibited a thinner thickness while demonstrating higher microhardness. • The corrosion resistance of the anodic oxide film prepared using the step voltage technique substantially exceeded that of the film produced using constant voltage. [ABSTRACT FROM AUTHOR]