bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance Analysis of a Solar Heating Ammonia Decomposition Membrane Reactor under Co-Current Sweep
Authors: Xie Tianchao , Xia Shaojun , Huang Jialuo , Wang Chao , Jin Qinglong
Published: October 2022

Ammonia is an excellent medium for solar thermal chemical energy storage and can also use excess heat to produce hydrogen without carbon emission. To deepen the study of ammonia decomposition in these two fields, finite-time thermodynamics is used to model a solar-heating, co-current sweeping ammonia decomposition membrane reactor. According to the needs of energy storage systems and solar hydrogen production, five performance indicators are put forward, including the heat absorption rate (HAR), ammonia conversion rate (ACR), hydrogen production rate (HPR), entropy generation rate (EGR) and energy conversion rate (ECR). The effects of the light intensity, ammonia flow rate, nitrogen flow rate and palladium membrane radius on system performances are further analyzed. The results show that the influences of the palladium membrane radius and nitrogen flow rate on reactor performances are very slight. When the light intensity is increased from 500 W/m2 to 800 W/m2, the ACR, EGR, HAR and HPR increase obviously, but the ECR decreases by 14.2%. When the ammonia flow rate is increased by 100%, the ECR, EGR and HPR increase by more than 70%, the HAR increases by 15.6% and the ACR decreases by 12.9%. At the same time, the ammonia flow rate needs to be adjusted with the light intensity. The results can provide some guiding significance for the engineering application of ammonia solar energy storage systems and solar hydrogen production.
Amphiphilic Chitosan Porous Membranes as Potential Therapeutic Systems with Analgesic Effect for Burn Care
Authors: Enache Andra-Cristina , Samoila Petrisor , Cojocaru Corneliu , Bele Adrian , Bostanaru Andra-Cristina , Mares Mihai , Harabagiu Valeria
Published: October 2022

Eliminating or at least lessening the pain is a crucial aspect of burns management, as pain can negatively affect mental health and quality of life, and it can also induce a delay on wound healing. In this context, new amphiphilic chitosan 3D porous membranes were developed and investigated as burns therapeutic systems with analgesic effect for delivery of lidocaine as local anesthetic. The highly porous morphology of the membranes and the structural modifications were evidenced by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis and infrared spectroscopy (FTIR). Improved compression mechanical properties, long-term hydrolytic degradation (28 days) evaluation and high swelling capacities (ranging from 8 to 22.6 g/g) indicate an increased capacity of the prepared membranes to absorb physiological fluids (burns exudate). Lidocaine in vitro release efficiency was favored by the decreased content of cross-linking agent (reaching maximum value of 95.24%) and the kinetic data modeling, indicating that lidocaine release occurs by quasi-Fickian diffusion. In addition to the in vitro evaluation of analgesic effect, lidocaine-loaded chitosan membranes were successfully investigated and proved antibacterial activity against most common pathogens in burns infections: Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus.
Active Starch-Polyester Bilayer Films with Surface-Incorporated Ferulic Acid
Authors: Hernández-García Eva , Vargas Maria , Chiralt Amparo
Published: October 2022

Bilayer films of cassava starch-based (with 10% gellan gum) and polylactic (PLA): Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) polyester blend (with 75% PLA) monolayers were obtained by melt-blending and compression-molding, and the subsequent thermocompressing of both monolayers. Ferulic acid (FA) was incorporated into the polyester sheet by spraying and drying. Films were characterized in terms of their microstructure and functional properties throughout two months of storage at 25 °C and 53% relative humidity. The laminates exhibited improved tensile and barrier properties compared to the respective monolayers, which makes them more adequate for food packaging purposes. Surface incorporation of ferulic acid did not significantly modify the barrier and mechanical properties of the films while providing them with antioxidant and antibacterial capacity when applied in aqueous systems, where a complete release of active compounds occurred. The physical properties of the bilayers and layer thermo-sealing were stable throughout storage. Likewise, the antioxidant and antimicrobial active properties were preserved throughout storage. Therefore, these active bilayers represent a sustainable packaging alternative to non-biodegradable, non-recyclable synthetic laminates for food packaging purposes, which could extend the shelf-life of food due to their antioxidant and antibacterial properties.
Atomistic-Scale Energetic Heterogeneity on a Membrane Surface
Authors: Tan Shiliang (Johnathan) , Ong Chisiang , Chew Jiawei
Published: October 2022

Knowing the energetic topology of a surface is important, especially with regard to membrane fouling. In this study, molecular computations were carried out to determine the energetic topology of a polyvinylidene fluoride (PVDF) membrane with different surface wettability and three representative probe molecules (namely argon, carbon dioxide and water) of different sizes and natures. Among the probe molecules, water has the strongest interaction with the PVDF surface, followed by carbon dioxide and then argon. Argon, which only has van der Waals interactions with PVDF, is a good probing molecule to identify crevices and the molecular profile of a surface. Carbon dioxide, which is the largest probing molecule and does not have dipole moment, exhibits similar van der Waals and electrostatic interactions. As for water, the dominant attractive interactions are electrostatics with fluorine atoms of the intrinsically hydrophobic PVDF membrane, but the electrostatic interactions are much stronger for the hydroxyl and carboxyl groups on the hydrophilic PVDF due to strong dipole moment. PVDF only becomes hydrophilic when the interaction energy is approximately doubled when grafted with hydroxyl and carboxyl groups. The energetic heterogeneity and the effect of different probe molecules revealed here are expected to be valuable in guiding membrane modifications to mitigate fouling.
Novel O-Methylglucoside Derivatives of Flavanone in Interaction with Model Membrane and Transferrin
Authors: Cyboran-Mikołajczyk Sylwia , Bonarska-Kujawa Dorota , Męczarska Katarzyna , Krawczyk-Łebek Agnieszka , Kostrzewa-Susłow Edyta
Published: October 2022

Flavonoids were biotransformed using various microorganisms, in order to obtain new compounds with potentially high biological activity. The aim of this work was to determine and compare the biological activity of four novel 6-methylflavanone O-methylglucosides. The tested compounds have the same flavonoid core structure and an attached O-methylglucose and hydroxyl group at different positions of ring A or B. The studies on their biological activity were conducted in relation to phosphatidylcholine membrane, erythrocytes and their membrane, and with human transferrin. These studies determined the compounds’ toxicity and their impact on the physical properties of the membranes. Furthermore, the binding ability of the compounds to holo-transferrin was investigated. The obtained results indicate that used compounds bind to erythrocytes, change their shape and decrease osmotic fragility but do not disrupt the membrane structure. Furthermore, the used compounds ordered the area of the polar heads of lipids and increased membrane fluidity. However, the results indicate the binding of these compounds in the hydrophilic region of the membranes, like other flavonoid glycosides. The used flavanones formed complexes with transferrin without inducing conformational changes in the protein’s structure. The relationship between their molecular structure and biological activity was discussed.
Structural and Electrotransport Properties of Perfluorinated Sulfocationic Membranes Modified by Silica and Zirconium Hydrophosphate
Authors: Shkirskaya Svetlana A. , Kononenko Natalia A. , Timofeev Sergej V.
Published: October 2022

A correlation between changes in structural and electrotransport properties of membranes after modification by silica and zirconium hydrophosphate was established. The total water volume, volume fraction of the free water in the membrane and the volume fraction of the water having high binding energy were considered as structural characteristics, which were found from the curves of water distribution on the water binding energy and the effective pore radii. The conductivity, diffusion and electroosmotic permeabilities were investigated as electrotransport properties. The influence of the modifier type on the current flow paths in the membrane was analyzed within the framework of the extended three-wire model. It has been established that the treatment of membranes with alcohol before the intercalation of a modifier leads to the appearance of cavities with an effective size of more than 100 nm filled with free water with the binding energy less than 10 J/mol. It is accompanied with an increase in the diffusion permeability of hybrid membranes by approximately 3–6 times in NaCl and HCl solutions, which limits the application of such materials in proton exchange membrane fuel cells. The different conditions of modification of perfluorinated membranes with similar properties by the dopant with same type allow for the preparation of the hybrid materials for various applications such as electrodialysis concentration or electric current generation devices.
Comparative Investigation of the Corrosion Behavior and Biocompatibility of the Different Chemical Conversion Coatings on the Magnesium Alloy Surfaces
Authors: Meng Lingjie , Liu Xuhui , Liu Li , Hong Qingxiang , Cheng Yuxin , Gao Fei , Chen Jie , Zhang Qiuyang , Pan Changjiang
Published: October 2022

Due to their good biodegradability and biocompatibility, magnesium alloys are widely favored as the potential candidate for the biodegradable cardiovascular stent. However, the rapid degradation and the limited biocompatibility in vivo remain the main bottlenecks that inhibit their clinical applications. The construction of the chemical conversion coating on the magnesium alloy surface represents one of the effective strategies to control the degradation rate and enhance the biocompatibility. In the present study, the different chemical conversion layers were prepared on the magnesium alloy surface by chemical conversion treatment, including sodium hydroxide (NaOH), hydrofluoric acid (HF), phosphoric acid (H3PO4) and phytic acid (C6H18O24P6) treatment, and the corrosion behaviors and biocompatibility of the chemical conversion layers were comparatively investigated in detail. The results showed that the different chemical treatments can produce the different conversion layers on the magnesium alloy surfaces with a variety of physicochemical characteristics, corrosion resistance and biocompatibility, and all treatments can enhance the corrosion resistance to varying degrees. The hydrophilicity and corrosion resistance of the sodium hydroxide-treated magnesium alloy were the best among all the materials. Although the hydrofluoric acid-treated magnesium alloy had produced a hydrophobic coating, the corrosion resistance still needed to be improved. Magnesium alloys treated by sodium hydroxide showed a selective promotion of albumin adsorption, while the other samples simultaneously promoted albumin and fibrinogen adsorption. For the blood compatibility, the hemolysis rates of all of the treated materials were reduced to below 5%. The samples treated by phytic acid had the smallest hemolysis rate, and the NaOH-treated magnesium alloy had the least amount of platelet adhesion and activation. An appropriate microenvironment for cell growth could be achieved by the chemical conversion treatment, according to the results of the endothelial cell adhesion and proliferation, and the NaOH-treated surface showed the best endothelial cell growth behaviors among all of the samples. In summary, the corrosion resistance and biocompatibility of the magnesium alloy were significantly improved by the sodium hydroxide treatment, and thus this treatment can be used as a pretreatment for the surface modification of the magnesium alloy in order to further enhance the biocompatibility when used as the cardiovascular implants.
Investigation of the Microstructure and Mechanical Properties of an Ultrahigh Strength Martensitic Steel Fabricated Using Laser Metal Deposition Additive Manufacturing
Authors: Wang Min , Zhang Qican , Li Wengang , Zhang Zhen , Chui Pengfei , Yu Zhiting , Zhang Kun
Published: October 2022

Ultrahigh strength steels were additively manufactured (AM) using different batches of powders by means of the laser metal deposition (LMD) technique. After quenching and tempering treatments, the microstructures, mechanical properties, and fracture modes of ultrahigh strength steels were investigated by several testing methods. The results demonstrate that martensite and Fe3C cementite were found in the three specimens after quenching and tempering treatments, and the tempered martensite microstructure had a lamellar structure in all specimens. The widths of these martensite lathes were observed to be different for the APHT-1, APHT-2, and APHT-3 samples, and their sizes were 1.92 ± 0.90 μm, 1.87 ± 1.09 μm, and 1.82 ± 0.85 μm, respectively. The martensitic steel exhibited excellent mechanical properties (tensile strength and impact toughness). The yield strength and the ultimate tensile strength of the APHT-3 sample reached 1582 MPa and 1779 MPa, respectively. Moreover, the value of the impact energy for the APHT-1 sample was 46.4 J. In addition, with the changes in the batches of ultrahigh strength steel powders, the fracture mode changed from ductile fracture to brittle fracture under tensile force and impact loads.
The Role of Microparticles of β-TCP and Wollastonite in the Creation of Biocoatings on Mg0.8Ca Alloy
Authors: Sedelnikova Mariya , Bakina Olga , Ugodchikova Anna , Tolkacheva Tatiana , Khimich Margarita , Uvarkin Pavel , Kashin Alexander , Miller Andrey , Egorkin Vladimir , Schmidt Juergen , Sharkeev Yurii
Published: October 2022

The introduction of particles into the composition of coatings can significantly expand the range of properties and possibilities of the modified materials. In this work, the coatings containing microparticles of β-tricalcium phosphate (β-TCP) and wollastonite separately and in combination with each other were created on the surface of an Mg0.8Ca alloy. The morphology and microstructure of the coatings were examined by scanning and transmission electron microscopy. Their phase composition was determined with the help of X-ray diffraction analysis. The coating-to-substrate adhesion evaluation was carried out via the scratch-test method. Potentiodynamic polarization curves of the coatings were obtained during their immersion in 0.9% NaCl solution and their electrochemical properties were determined. Cytotoxic properties of the coatings were investigated by means of the MTT assay and flow cytometry in the course of the biological studies. In addition, NIH/3T3 cell morphology was analyzed using scanning electron microscopy. The structure, morphology, physical and mechanical, corrosive, and biological properties of the coatings depended on the type of particles they contained. Whereas the coating with β-TCP microparticles had higher adhesive properties, the coatings with wollastonite microparticles, as well as the combined coating, were less soluble and more biocompatible. In addition, the wollastonite-containing coating had the highest corrosion resistance.
Computational Investigation on Cracking Behaviors of AerMet 100
Authors: Zhang Hongbo , Hu Dayong , Meng Kangpei
Published: October 2022

AerMet 100 exhibits excellent mechanical properties, proven in previous studies; however, defects may greatly influence the mechanical behavior during the service of the material, which serves as one of the major challenges in the wider application of the material. To quantify the crack evolution process, the in-plane type I crack propagation behavior is comprehensively investigated based on the extended finite element method (XFEM). The crack growth is characterized in terms of the extracted crack propagation angle, stress intensity factor (SIF) in the crack tip, and stress field profiles during the crack propagation process. An extrapolation method is adopted to calculate the SIF, followed by a series of parametric studies on the influence of the governing factors, i.e., initial crack length, initial crack location, initial crack angle, and the crack number through numerical investigation. It is found that the crack propagation angle enlarges monotonously with the increase of the initial crack location, the initial crack length, and the crack number, increases slowly with the growth of initial crack angle, and rapidly enlarges in reverse at about 45°. The SIF in Mode I, KId, gradually decreases with the increase of the initial crack location and the crack number, and nearly keeps steady when the initial crack length and initial crack angle varies. Results provide further understanding of the failure and fracture behavior of AerMet 100 and guide the future application and design of the structures.
The Role of Dilute Solute Additions on Growth Restriction in Cu-, Al-, Mg- and Ti-Based Alloys
Authors: Balart Maria J. , Gao Feng , Patel Jayesh B. , Miani Fabio
Published: October 2022

The effect of dilute solute additions on growth restriction in Cu-, Al-, Mg- and Ti-based binary and ternary alloys was assessed by means of the heuristic growth restriction parameter (β) modelling framework. The CALPHAD (calculation of phase diagrams) methodology was used to calculate β values from the m and k values, at first approximation, as well as from the liquid-to-solid fraction to obtain true β values. Grain size values from the literature were plotted against the corresponding true β values, showing a negative or inverse correlation between the two.
Effect of Heat Input on Microstructure and Corrosion Resistance of X80 Laser Welded Joints
Authors: Zhao Wei , Wang Jia , Li Zhen , Guo Ning , Gao Song
Published: October 2022

Using fiber laser welding technology, X80 pipeline steel welded joints with different welding heat inputs were obtained. Their microstructure, mechanical properties, and corrosion resistance (in NACEA solution saturated with hydrogen sulfide) were studied. Findings indicated that with the increase in heat input, the proportion of ferrite, strength, elongation, and corrosion resistance increased within a certain range and the sum of the proportion of martensite and bainite and hardness decreased. The heat input has a greater effect on the microstructure of weld metal (WM) and coarse-grained heat-affected zone (CGHAZ), while that of fine-grained heat-affected zone (FGHAZ) is basically unchanged. Obvious differences are also found in the corrosion resistance of different regions of the welded joints, among which FGHAZ has the strongest corrosion resistance, followed by WM and CGHAZ. The heat input mainly affects the microstructure type of the welded joint to affect the corrosion resistance. Therefore, we model the heat input as a function of Rct and icorr from this relationship. In addition, the corrosion products film produced by the long-term immersion of the welded joint in the saturated H2S NACEA solution can hinder the development of corrosion and enhance the corrosion resistance to a certain extent.
Microstructure and Texture of 2205 Duplex Stainless Steel Additive Parts Fabricated by the Cold Metal Transfer (CMT) Wire and Arc Additive Manufacturing (WAAM)
Authors: Bi Xiaolin , Li Ruifeng , Hu Zhenxing , Gu Jiayang , Jiao Chen
Published: October 2022

Additive parts made of 2205 duplex stainless steel were fabricated by cold metal transfer (CMT) wire and arc additive manufacturing (WAAM), and their microstructure and properties were systematically studied. The X-ray diffraction results show that austenite phase and ferrite phase were formed in the additive parts. Due to the low heat input characteristics of CMT-WAAM, no σ phase was observed. The microstructure in the additive parts was different from the bottom to the top, with the content of austenite phase gradually increasing and that of ferrite gradually decreasing. The EBSD results indicate that the ferrite phase in the bottom part grew parallel to the normal direction of {100}. However, the ferrite phase in the middle part grew parallel to the plane composed of the build direction and normal direction, and along {100} and {111}. The effect of the ferrite and austenite contents on the mechanical performance of the additive parts was simulated using the LAMMPS software. The simulation results exhibit a common characteristic in that the dislocations move mainly along the 1/6<112> crystallographic direction families. The simulated maximum tensile stress values of the bottom, middle, and top parts were 23.3 GPa, 22.3 Gpa, and 22.5 Gpa, respectively. The data from the bottom tensile strength simulation were consistent with the actual data, and the bottom tensile strength was the largest in the actual tensile process.
Process Modelling Applied to Aluminium-Steel Butt Welding by Hybrid Metal Extrusion and Bonding (HYB)
Authors: Leoni Francesco , Grong Øystein , Celotto Ambra , Fjær Hallvard Gustav , Ferro Paolo , Berto Filippo
Published: October 2022

In the present investigation, the numerical code WELDSIM is used to simulate butt welding of 4 mm thick plates of S355 steel and AA6082-T6 by Hybrid Metal Extrusion and Bonding (HYB). This is a new solid state joining process using continuous extrusion as a technique to enable aluminium filler metal additions. In WELDSIM, the finite element heat flow model is coupled to a frictional heating model, an isokinetic diffusion model for the interfacial intermetallic compound (IMC) formation and a nanostructure model for simulating reversion and re-precipitation of hardening phases inside the aluminium part of the joints during welding and subsequent natural ageing. The HYB process model is validated by comparison with experimental data obtained from in-situ thermocouple measurements and hardness testing carried out on three different Al-steel butt welds. Furthermore, scanning electron microscope examinations of the Al-steel interfaces have been conducted to check the predicted power of the IMC diffusion model. It is concluded that the process model is sufficiently relevant and comprehensive to be used in simulations of both the thermal, microstructure, and strength evolutions fields in these dissimilar butt welds. Some practical applications of the process model are described toward the end of the article, where particularly its potential for optimising the load-bearing capacity of the joints, is highlighted.
Strength–Ductility Matching Mechanism for Multi-Phase Microstructure Control of High-Ductility Ship Plate Steel
Authors: Wang Enmao , Wu Huibin , Mi Zhenli , Liu Jinxu
Published: October 2022

Generally, the development of ship plate steels is mainly concerned with the improvement of strength and toughness, such as F32 and F36. Due to the strength–ductility trade-off, it is difficult to combine excellent ductility with strength improvement, resulting in a poor deformation ability of the traditional ship plate steels during collision. In the present study, a series of high-ductility ship plate steels with property gradients were obtained by multi-phase microstructure control. The strength–ductility matching mechanism was analyzed. Meanwhile, the roles of M/A islands and lamellar pearlites in plastic deformation were also revealed. The results show that the microstructure of “quasi-polygonal ferrite + granular bainite + M/A islands + fewer lamellar pearlites” has the best strength–ductility match. The excellent ductility is mainly dependent on dispersive kernel average misorientation, recrystallized grains without distortion, and soft grains. In addition, the longer branch crack can effectively relieve the stress concentration at the tip of the main crack. Compared with lamellar pearlites, the dispersed M/A island grains have a higher strength contribution and more stable γ-fibers, which is beneficial to delay the appearance of internal micro-voids and micro-cracks. However, the lamellar pearlites can coordinate deformation only when the orientation of thinner lamellae exceeds two.
Influence of the Tool Rotational Speed on Physical and Chemical Properties of Dissimilar Friction-Stir-Welded AA5083/AA6060 Joints
Authors: Laska Aleksandra , Szkodo Marek , Cavaliere Pasquale , Perrone Angelo
Published: October 2022

Aluminum alloys have been successfully used in the railroad and automotive industries because of their potential to significantly reduce component weights, and their good mechanical and anti-corrosion properties. Problems with joining aluminum alloys are characterized by low weldability, which influences the need for studies focused on unconventional methods. The environmentally friendly and low-cost friction-stir-welding method enables the material to be joined without melting. In the following study, dissimilar butt joints were produced from AA5083 and AA6060 alloys. A constant tool traverse speed of 100 mm/min and a tool tilt angle of 2º were used, combined with tool rotational speeds of 800, 1000 and 1200 RPM. It was revealed that as the tool speed increases, the hardness in the weld nugget zone increases, due to higher heat input and more effective recrystallization. The highest hardness of the weld nugget zone was observed for the weld that was produced with the highest tool rotational speed, and was equal to 1.07 GPa, compared to the hardness of both parent materials of 0.75 and 1.15 GPa for AA5083 and AA6060, respectively. Increasing the heat input also decreased the hardness of the heat-affected zone, where recrystallization was not observed. The lowest density of dislocations with the highest mobility was observed in the heat-affected zone on the AA6060 side, which also contributed to the reduction in strength in this zone. The produced welds exhibited corrosion resistance between both parent materials, with the lowest corrosion current density being 6.935 ± 0.199 µA·cm−2 for the weld that was produced at a tool speed of 1200 RPM.
Paste-Injection of Low-Density Barium Hexaferrite Magnets with Soft Magnetic Iron Phase
Authors: Thongsamrit Wannisa , Jantaratana Pongsakorn , Charoensuk Thanida , Sirisathitkul Chitnarong
Published: October 2022

Permanent magnets of varying shapes and sizes are increasingly produced. For hexaferrite magnets, it is challenging to incorporate polymers and a soft magnetic phase in the form of paste before injection molding or extrusion free-forming. In this study, hard magnetic barium hexaferrite/soft magnetic iron composites with a density of 2.28–2.34 g/cm3 are obtained after paste-injection molding and subsequent sintering at 1150 °C for 5 h. Variations of the binder (143.5–287.0 mg poly(vinyl alcohol), PVA) and the plasticizer (75–150 mg poly(ethylene glycol), PEG-400) in the ceramic–polymer paste give rise to comparable remanent magnetization (33.10–33.63 emu/g) and coercivity (3854–3857 Oe). Unlike all-ferrite systems, the presence of a soft magnetic metal phase is not detrimental to the coercivity. However, the remanent and saturation magnetizations are not substantially increased. The addition of 1% and 5% of iron oxide in the ceramic–polymer paste gives rise to hard/soft composites with lower densities of 2.11 and 2.14 g/cm3. The coercivity is increased to 3942–3945 Oe; however, the maximum energy product is reduced.
Shock Hugoniot of Forged and Additively Manufactured 304L Stainless Steel
Authors: Thomas Sarah A. , Hawkins Michelle C. , Hixson Robert S. , Martinez Ramon M. , Gray George T. , Luscher Darby J. , Fensin Saryu J.
Published: October 2022

The purpose of this research was to measure the equation of state for additively manufactured (AM) and forged 304L stainless steel using a novel experimental technique. An understanding of the dynamic behavior of AM metals is integral to their timely adoption into various applications. The Hugoniot of the AM 304L was compared to that of the forged 304L at particle velocities where the material retains a two-wave structure. This comparison enabled us to determine the sensitivity of the equation of state to microstructure as varied due to processing. Our results showed that there was a measurable difference in the measured shock velocity between the AM and forged 304L. The shock wave velocities for the AM 304L were found to be ~3% slower than those for the forged 304L at similar particle velocities. To understand these differences, properties such as densities, sound speeds, and texture were measured and compared between the forged and AM materials. Our results showed that no measurable difference was found in these properties. Additionally, it is possible that differing elastic wave amplitudes may influence shock velocity
Improved SVM Model for Predicting Pellet Metallurgical Properties Based on Textural Characteristics
Authors: Han Yang , Wang Lijing , Wang Wei , Xue Tao , Zhang Yuzhu
Published: October 2022

From the point of view that pellet microstructure determines its metallurgical properties, an improved support vector machine (SVM) model for pellet metallurgical properties forecast is studied based on the mineral phase characteristics, in order to improve the evaluation efficiency of pellet metallurgical properties. The forecast model is composed of a SVM with self-adaptive selection of kernel parameters and a SVM with self-adaptive compounding of kernel types. This not only guarantees the super interpolation ability of the forecast model, but also takes into account its good generalization performance. Based on 200 sets of original sample information, the quantitative relationship between the main characteristics of mineral phase and the grade labels of pellet metallurgical properties (reduction expansion index RSI, reduction index RI, low temperature reduction and pulverization index RDI) was determined by the improved SVM model. With the simulation results of RSI, RI, and RDI with the accuracy of 100%, 98%, and 100% respectively, the precise forecast of pellet metallurgical properties based on mineral phase is realized.
Improvement in Electrical Stability of a-IGZO TFTs Using Thinner Dual-Layer Dielectric Film
Authors: Kim Jong-Woo , Seo Hyun Kyu , Lee Su Yeon , Park Minsoo , Yang Min Kyu , Ju Byeong-Kwon
Published: October 2022

This study investigates the effect of gate insulators on thin-film transistors (TFTs) using an amorphous InGaZnO4 (a-IGZO) channel layer. TFTs with single-layer Ta2O5 and dual-layer Ta2O5/SiO2 gate insulators were fabricated on a glass substrate. An evaluation of the insulating film using the MIM (Metal-Insulator-Metal) structure confirmed its electrical characteristics. Microscopic imaging showed that the dual-layer Ta2O5/SiO2 dielectric significantly improved surface characteristics. A reduction in the leakage current, better on/off ratios, and a decreased subthreshold swing (SS) compared to a single-layer Ta2O5 dielectric were reported. The dual-layer insulator composed of SiO2/Ta2O5 was highly effective in improving device characteristics.
Void Mediated Failure at the Extremes: Spallation in Magnesium and Aluminum
Authors: Williams Cyril Labode
Published: October 2022

This paper reviews the role of void nucleation, growth, and coalescence on the spall failure process in light metals. Based on the review of the open literature, the preponderance of evidence show that void nucleation, growth, and coalescence are prevalent in light metals such as HCP magnesium and FCC aluminum alloys. The as-received microstructure and its evolution play a crucial role on how voids nucleate, grow, and coalesce. Nucleation of voids in these light metals and metallic alloys can be either homogeneous and heterogeneous but at high enough stresses, both homogeneous and heterogeneous nucleation can be activated simultaneously. Secondary phase particles and intermetallics can strongly influence spall failure, through matrix-precipitate/intermetallic debonding or precipitate/intermetallic cracking during shock compression. Studying spall failure through modeling has proven to be an invaluable tool in developing a fundamental understanding of void nucleation, growth, coalescence, and consequent spall failure. However, since new alloys are currently been developed, more experimental and modeling research are needed to further understand how spall failure initiate and grow in these new alloys.
Influence Evaluation of Tungsten Content on Microstructure and Properties of Cu-W Composite
Authors: Li Xiuqing , Zhang Minjie , Zhang Guoshang , Wei Shizhong , Wang Qi , Lou Wenpeng , Liang Jingkun , Chen Liangdong , Xu Liujie , Zhou Yucheng , Pan Kunming
Published: October 2022

At present, most studies focus on Cu-W composites with high W content (W content > 50 wt%), while there are only sporadic reports on Cu-W composites with low W content (W content < 50 wt%). In this work, Cu-W composites with different W contents (0, 10 wt%, 20 wt% and 30 wt%) were prepared, and the effects of W content on microstructure, density, hardness, electrical conductivity, strength and electrical contact properties were systematically studied, with the expectation of providing an experimental basis and theoretical support for expanding the application range of Cu-W composites with low W content. The results showed that, with the increase in W content, the Cu matrices divided into finer and more uniform grains; the density and electrical conductivity of Cu-W composites decreased; and the compressive yield strength and hardness gradually increased. As the content of W increased, the arc burning time of the Cu-W composite contacts began to fluctuate. There was a loss of both the cathode and the anode contacts of the pure Cu, but the mass transfer of the Cu-W composite contacts occurred as follows: the anode weight increases, while the cathode weight decreases. The addition of W particles changed the non-uniform ablation of the pure Cu, and the surface ablation of the Cu-W composite contacts remained uniform.
Effects of Laser-Deposited Maraging Steel on L-PBF 316L Component
Authors: Errico Vito , Posa Paolo , Mazzarisi Marco , Angelastro Andrea , Campanelli Sabina Luisa
Published: October 2022

The capabilities of additive manufacturing (AM) techniques have been extensively examined in the literature. However, scientific gaps persist on the feasibility of realizing a coated component manufactured by using various materials processed by combining different AM processes. From this perspective, this study focuses on the manufacturing of a directed energy deposition (DED) coating by using 18Ni (300) maraging steel powder on AISI 316L components realized by laser-powder bed fusion (L-PBF), in order to assess the production of components with high geometrical complexity combined with high mechanical surface properties in selected areas. The quality of the manufactured coatings was assessed in-process through the implementation of an optical monitoring system and real-time image processing. In addition, an in-depth metallurgical analysis (microstructural and chemical) of the interface between the DED coating and the L-PBF component was carried out. Finally, hardness tests were performed on both the as-deposited and heat-treated coatings to confirm the high mechanical performance of the final component surface. The results revealed the potential of producing cost-effective and geometrically complex parts, such as molds or tools with internal cooling channels, that implement mechanically high-performance surfaces.
Surface Nanocrystallization and Numerical Modeling of 316L Stainless Steel during Ultrasonic Shot Peening Process
Authors: Li Pengyi , Hu Shan , Liu Yanxiong , Hua Lin , Yin Fei
Published: October 2022

Surface nanocrystallization of metals and alloys via high-frequency ultrasonic shot peening (USP) can significantly increase the mechanical properties of the materials. However, the relationship between the external process parameters and the internal microstructure of the materials is still unclear and an accurate numerical model to simulate the USP process is urgently required for better control of the grain refinement process. In this study, we successfully realized surface nanocrystallization of 316L stainless steel using USP with an ultrasonic frequency and amplitude of 20 kHz and 50 μm, respectively. The microstructure evaluation of 316L stainless steel during USP was revealed. We established a finite element numerical model to simulate the high-frequency USP process and calculated the plastic strain and stress distribution of 316L stainless steel during the grain refinement process. We investigated the effects of the ultrasonic frequency, working distance, and ultrasonic amplitude on the plastic strain and stress distribution on the materials using the finite element simulation method. The dynamic behavior of the shot during the USP process was studied using a high-speed camera, and the FE simulation results agreed well with the experimental results. We also investigated the impact of multiple shots during the USP process by the high-speed camera observation and FE simulation. Research results indicate that high-frequency USP is an effective method to obtain large-scale bulk nanocrystalline materials and the finite element simulation can help materials scientists and engineers to better understand the relationship between the process parameters and microstructure evaluation of 316L stainless steel.
Understanding Fe-Containing Intermetallic Compounds in Al Alloys: An Overview of Recent Advances from the LiME Research Hub
Authors: Que Zhongping , Wang Yun , Mendis Chamini L. , Fang Changming , Xia Junhai , Zhou Xiaorong , Fan Zhongyun
Published: October 2022

Control of Fe in Al alloys is a severe challenge for the full metal circulation to produce the recycled alloys with mechanical and physical performance as high as the primary alloys. The high restriction of Fe content is mainly due to the deterioration caused by the large-scale Fe-containing intermetallic compounds (FIMCs) in Al alloys. In this paper, recent knowledge gained regarding nucleation, formation, and technical developments on microstructural control and refinement of FIMCs are overviewed. Specific characteristics of the multiple types of FIMCs in Al alloys are presented in two- and three- dimensional (2D and 3D) form. Phase relationships between the FIMCs in different structures, such as primary phase, binary eutectic, and ternary eutectic, formed at different solidification stages are studied. Phase transformations between the FIMCs with or without intermediate phases during the solidification process are examined in different Al alloys, with the mechanisms being clarified. Various approaches to microstructural control of FIMCs are proposed and validated. Significant refinement of FIMCs has been achieved through inoculation of TiB2 particles that had been previously modified with deliberately interfacial segregation of desirable alloying elements, leading to the development of the novel “compositional templating” concept.
Investigating the Effect of SiCp Particle Shape on the Mechanical Behaviors of SiCp/WE43 Magnesium Matrix Composites by Finite Element Simulation
Authors: Wu Hulin , Li Weihan , Feng Yongjun , Xiang Lin , Xie Zhiwen
Published: October 2022

Previous results reported that SiCp (Silicon Carbide particles) particle doping proved to be effective in enhancing the wear performance of WE43 magnesium alloy. In this work, finite element simulation was employed to investigate the effect of SiCp particle shape on the mechanical behaviors of SiCp/WE43 magnesium matrix composites. SiCp particles underwent larger load internally and a smaller plastic deformation under tensile loading, leading to the enhanced strength and stiffness of the composites. Polygonal SiCp particles provided a better enhancement in strength for the composites than round SiCp particles, but the enhancement in stiffness was opposite. Meanwhile, the damage is likely to initiate at the interface between the matrix and particle, at the location of the highest stress concentration. This phenomenon was more prominent in polygonal particle-reinforced composites. These current findings provide a comprehensive understanding of the effect of SiCp particle shape on the mechanical behaviors of magnesium matrix composites.
Galectin-1 in Obesity and Type 2 Diabetes
Authors: Fryk Emanuel , Silva Vagner R. R. , Jansson Per-Anders
Published: October 2022

Galectin-1 is a carbohydrate-binding protein expressed in many tissues. In recent years, increasing evidence has emerged for the role of galectin-1 in obesity, insulin resistance and type 2 diabetes. Galectin-1 has been highly conserved through evolution and is involved in key cellular functions such as tissue maturation and homeostasis. It has been shown that galectin-1 increases in obesity, both in the circulation and in the adipose tissue of human and animal models. Several proteomic studies have independently identified an increased galectin-1 expression in the adipose tissue in obesity and in insulin resistance. Large population-based cohorts have demonstrated associations for circulating galectin-1 and markers of insulin resistance and incident type 2 diabetes. Furthermore, galectin-1 is associated with key metabolic pathways including glucose and lipid metabolism, as well as insulin signalling and inflammation. Intervention studies in animal models alter animal weight and metabolic profile. Several studies have also linked galectin-1 to the progression of complications in diabetes, including kidney disease and retinopathy. Here, we review the current knowledge on the clinical potential of galectin-1 in obesity and type 2 diabetes.
Transcriptomic-Metabolomic Profiling in Mouse Lung Tissues Reveals Sex- and Strain-Based Differences
Authors: Fernandes Jolyn , Dunigan-Russell Katelyn , Zhong Hua , Lin Vivian , Silverberg Mary , Moore Stephanie B. , Tran ViLinh , Jones Dean P. , Vitiello Peter F. , Rogers Lynette K. , Tipple Trent E.
Published: October 2022

Omics analyses are commonly used for identifying pathways and genes responsible for physiologic and pathologic processes. Though sex is considered a biological variable in rigorous assessments of pulmonary responses to oxidant exposures, the contribution of the murine strain is largely ignored. This study utilized an unbiased integrated assessment of high-resolution metabolomic profiling and RNA-sequencing to explore sex- and strain-dependent pathways in adult mouse lungs. The results indicated that strain exhibited a greater influence than sex on pathways associated with inflammatory and oxidant/antioxidant responses and that interaction metabolites more closely resembled those identified as differentially expressed by strain. Metabolite analyses revealed that the components of the glutathione antioxidant pathway were different between strains, specifically in the formation of mixed disulfides. Additionally, selenium metabolites such as selenohomocystiene and selenocystathionine were similarly differentially expressed. Transcriptomic analysis revealed similar findings, as evidenced by differences in glutathione peroxidase, peroxiredoxin, and the inflammatory transcription factors RelA and Jun. In summary, an multi-omics integrated approach identified that murine strain disproportionately impacts baseline expression of antioxidant systems in lung tissues. We speculate that strain-dependent differences contribute to discrepant pulmonary responses in preclincal mouse models, with deleterious effects on clinical translation.
Scopoletin Induced Metabolomic Profile Disturbances in Zebrafish Embryos
Authors: Yao Weixuan , Chen Jingpei , Lin Zhanyu , Wang Nani , Wang Anli , Wang Binjie , Wu Yuanzhao , Xu Zhongshi , Wang Jiye
Published: October 2022

Scopoletin, a typical example of a coumarin compound, exists in several Artemisia species and other plant genera. However, the systemic metabolic effects induced by scopoletin remain unclear. In the present study, we evaluated the metabolic profiles in scopoletin-exposed zebrafish embryos using UHPLC-Q-Obitrap-HRMS combined with multivariate analysis. Compared with the control group, 33 metabolites in scopoletin group were significantly upregulated, while 27 metabolites were significantly downregulated. Importantly, scopoletin exposure affected metabolites mainly involved in phosphonate and phosphinate metabolism, vitamin B6 metabolism, histidine metabolism, sphingolipid metabolism, and folate biosynthesis. These results suggested that scopoletin exposure to zebrafish embryos exhibited marked metabolic disturbance. This study provides a perspective of metabolic impacts and the underlying mechanism associated with scopoletin exposure.
Cheminformatics Identification and Validation of Dipeptidyl Peptidase-IV Modulators from Shikimate Pathway-Derived Phenolic Acids towards Interventive Type-2 Diabetes Therapy
Authors: Balogun Fatai Oladunni , Naidoo Kaylene , Aribisala Jamiu Olaseni , Pillay Charlene , Sabiu Saheed
Published: October 2022

Recently, dipeptidyl peptidase-IV (DPP-IV) has become an effective target in the management of type-2 diabetes mellitus (T2D). The study aimed to determine the efficacy of shikimate pathway-derived phenolic acids as potential DPP-IV modulators in the management of T2D. The study explored in silico (molecular docking and dynamics simulations) and in vitro (DPP-IV inhibitory and kinetics assays) approaches. Molecular docking findings revealed chlorogenic acid (CA) among the examined 22 phenolic acids with the highest negative binding energy (−9.0 kcal/mol) showing a greater affinity for DPP-IV relative to the standard, Diprotin A (−6.6 kcal/mol). The result was corroborated by MD simulation where it had a higher affinity (−27.58 kcal/mol) forming a more stable complex with DPP-IV than Diprotin A (−12.68 kcal/mol). These findings were consistent with in vitro investigation where it uncompetitively inhibited DPP-IV having a lower IC50 (0.3 mg/mL) compared to Diprotin A (0.5 mg/mL). While CA showed promising results as a DPP-IV inhibitor, the findings from the study highlighted the significance of medicinal plants particularly shikimate-derived phenolic compounds as potential alternatives to synthetic drugs in the effective management of T2DM. Further studies, such as derivatisation for enhanced activity and in vivo evaluation are suggested to realize its full potential in T2D therapy.