bluuebunny/crossref_metadata_2025 huggingface dataset:
Phosphorus Concentration in Water Affects the Biofilm Community and the Produced Amount of Extracellular Polymeric Substances in Reverse Osmosis Membrane Systems
Authors: Javier Luisa , Pulido-Beltran Laura , Kruithof Joop , Vrouwenvelder Johannes S. , Farhat Nadia M.
Published: November 2021

Biofouling is a problem that hinders sustainable membrane-based desalination and the stratification of bacterial populations over the biofilm’s height is suggested to compromise the efficiency of cleaning strategies. Some studies reported a base biofilm layer attached to the membrane that is harder to remove. Previous research suggested limiting the concentration of phosphorus in the feed water as a biofouling control strategy. However, the existence of bacterial communities growing under phosphorus-limiting conditions and communities remaining after cleaning is unknown. This study analyzes the bacterial communities developed in biofilms grown in membrane fouling simulators (MFSs) supplied with water with three dosed phosphorus conditions at a constant biodegradable carbon concentration. After biofilm development, biofilm was removed using forward flushing (an easy-to-implement and environmentally friendly method) by increasing the crossflow velocity for one hour. We demonstrate that small changes in phosphorus concentration in the feed water led to (i) different microbial compositions and (ii) different bacterial-cells-to-EPS ratios, while (iii) similar bacterial biofilm populations remained after forward flushing, suggesting a homogenous bacterial community composition along the biofilm height. This study represents an exciting advance towards greener desalination by applying non-expensive physical cleaning methods while manipulating feed water nutrient conditions to prolong membrane system performance and enhance membrane cleanability.
Effects of Channel Thickness on Electrical Performance and Stability of High-Performance InSnO Thin-Film Transistors
Authors: Li Qi , Dong Junchen , Han Dedong , Wang Yi
Published: November 2021

InSnO (ITO) thin-film transistors (TFTs) attract much attention in fields of displays and low-cost integrated circuits (IC). In the present work, we demonstrate the high-performance, robust ITO TFTs that fabricated at process temperature no higher than 100 °C. The influences of channel thickness (tITO, respectively, 6, 9, 12, and 15 nm) on device performance and positive bias stress (PBS) stability of the ITO TFTs are examined. We found that content of oxygen defects positively correlates with tITO, leading to increases of both trap states as well as carrier concentration and synthetically determining electrical properties of the ITO TFTs. Interestingly, the ITO TFTs with a tITO of 9 nm exhibit the best performance and PBS stability, and typical electrical properties include a field-effect mobility (µFE) of 37.69 cm2/Vs, a Von of −2.3 V, a SS of 167.49 mV/decade, and an on–off current ratio over 107. This work paves the way for practical application of the ITO TFTs.
Development of Absorbent Using Amylose-Graphite Composite Electrode for Removal of Heavy Metals
Authors: Li Shuang , Mokhtar Guizani , Ito Ryusei , Kawaguchi Toshikazu
Published: November 2021

Amylose of Phragmites Australis captures heavy metals in a box consisting of sugar chains. However, its absorption rate is low in the period of the month scale. Therefore, the electrochemical driving force was used to promote the absorption rate in this research. Amylose was doped with TiO2 porous graphite electrode. The composted absorbent was characterized using XRD(X-ray diffraction), SEM (Scanning Electrode Microscopy), Raman spectroscopy, and electrochemical methods. The affinity and maximum absorption amount were calculated using the isotherm method. In this study, Pb2+, Cu2+, Cd2+, and Cr6+ were chosen to demonstrate because these heavy metals are significant pollutants in Japan’s surface water. It was found that the maximum absorption was Cu2+ (56.82-mg/L) > Pb2+ (55.89-mg/L) > Cr6+ (53.97-mg/L) > Cd2+ (52.83.68-mg/L) at −0.5 V vs. Ag/AgCl. This is approximately the same order as the hydration radius of heavy metals. In other words, the absorption amounts were determined by the size of heavy metal ions. Subsequently, the mixed heavy metal standard solution was tested; the maximum absorption amount was 21.46 ± 10.03 mg/L. It was inferred that the electrochemical driving force could be shown as the ion size effect in the mixed solution. Despite there being no support for this hypothesis at this time, this study succeeded in showing that the electrochemical driving force can improve the ability of the absorbent.
Membrane Distillation: Recent Configurations, Membrane Surface Engineering, and Applications
Authors: Parani Sundararajan , Oluwafemi Oluwatobi
Published: November 2021

Membrane distillation (MD) is a developing membrane separation technology for water treatment that involves a vapor transport driven by the vapor pressure gradient across the hydrophobic membrane. MD has gained wide attention in the last decade for various separation applications, including the separation of salts, toxic heavy metals, oil, and organic compounds from aqueous solutions. Compared with other conventional separation technologies such as reverse osmosis, nanofiltration, or thermal distillation, MD is very attractive due to mild operating conditions such as low temperature and atmospheric pressure, and 100% theoretical salt rejection. In this review, membrane distillation’s principles, recent MD configurations with their advantages and limitations, membrane materials, fabrication of membranes, and their surface engineering for enhanced hydrophobicity are reviewed. Moreover, different types of membrane fouling and their control methods are discussed. The various applications of standalone MD and hybrid MD configurations reported in the literature are detailed. Furthermore, studies on the MD-based pilot plants installed around the world are covered. The review also highlights challenges in MD performance and future directions.
Transport and Separation of the Silver Ion with n–decanol Liquid Membranes Based on 10–undecylenic Acid, 10–undecen–1–ol and Magnetic Nanoparticles
Authors: Nechifor Gheorghe , Păncescu Florentina Mihaela , Albu Paul Constantin , Grosu Alexandra Raluca , Oprea Ovidiu , Tanczos Szidonia-Katalin , Bungău Constantin , Grosu Vlad-Alexandru , Ioan Mihail-Răzvan , Nechifor Aurelia Cristina
Published: November 2021

This paper presents a transport and recovery of silver ions through bulk liquid membranes based on n–decanol using as carriers 10–undecylenic acid and 10–undecylenyl alcohol. The transport of silver ions across membranes has been studied in the presence of two types of magnetic oxide nanoparticles obtained by the electrochemical method with iron electrodes in the electrolyte with and without silver ions, which act as promoters of turbulence in the membrane. Separation of silver ions by bulk liquid membranes using 10–undecylenic acid and 10–undecylenyl alcohol as carriers were performed by comparison with lead ions. The configuration of the separation module has been specially designed for the chosen separation process. Convective-generating magnetic nanoparticles were characterized in terms of the morphological and structural points of view: scanning electron microscopy (SEM), high-resolution SEM (HR–SEM), energy dispersive spectroscopy analysis (EDAX), Fourier Transform InfraRed (FTIR) spectroscopy, thermal gravimetric analysis (TGA), differential scanning calorimetry and magnetization. The process performance (flux and selectivity) was tested were tested for silver ion transport and separation through n–decanol liquid membranes with selected carriers. Under the conditions of the optimized experimental results (pH = 7 of the source phase, pH = 1 of the receiving phase, flow rate of 30 mL/min for the source phase and 9 mL/min for the receiving phase, 150 rot/min agitation of magnetic nanoparticles) separation efficiencies of silver ions of over 90% were obtained for the transport of undecenoic acid and about 80% for undecylenyl alcohol.
Effect of Point Mutations on Structural and Allergenic Properties of the Lentil Allergen Len c 3
Authors: Melnikova Daria N. , Finkina Ekaterina I. , Bogdanov Ivan V. , Ignatova Anastasia A. , Matveevskaya Natalia S. , Tagaev Andrey A. , Ovchinnikova Tatiana V.
Published: November 2021

Plant lipid transfer proteins (LTPs) are known to be clinically significant allergens capable of binding various lipid ligands. Recent data showed that lipid ligands affected the allergenic properties of plant LTPs. In this work, we checked the assumption that specific amino acid residues in the Len c 3 structure can play a key role both in the interaction with lipid ligands and IgE-binding capacity of the allergen. The recombinant analogues of Len c 3 with the single or double substitutions of Thr41, Arg45 and/or Tyr80 were obtained by site-directed mutagenesis. All these amino acid residues are located near the “bottom” entrance to the hydrophobic cavity of Len c 3 and are likely included in the IgE-binding epitope of the allergen. Using a bioinformatic approach, circular dichroism and fluorescence spectroscopies, ELISA, and experiments mimicking the allergen Len c 3 gastroduodenal digestion we showed that the substitution of all the three amino acid residues significantly affected structural organization of this region and led both to a change of the ligand-binding capacity and the allergenic potential of Len c 3.
The Role of Sulphonic and Phosphoric Pendant Groups on the Diffusion of Monovalent Ions in Polyelectrolyte Membranes: A Molecular Dynamics Study
Authors: Abdulazeez Ismail , Salhi Billel , Baig Nadeem , Peng Qing
Published: November 2021

Lithium-ion consumption has risen significantly in recent years due to its use in portable devices. Alternative sources of lithium, which include the recovery from brine using the sustainable and eco-friendly electrodialysis technology, has been explored. This technology, however, requires effective cation-exchange membranes that allow the selective permeation of lithium ions. In this study, we have investigated, via molecular dynamics simulations, the role of the two common charged groups, the sulfonic and the phosphoric groups, in promoting the adsorption of monovalent ions from brine comprising Li+, Na+, Mg2+, and Ca2+ ions. The analysis of the mean square displacement of the ions revealed that Li+ and Na+ ions exhibit superior diffusion behaviors within the polyelectrolyte system. The O-atoms of the charged groups bind strongly with the divalent ions (Mg2+ and Ca2+), which raises their diffusion energy barrier and consequently lowers their rate of permeation. In contrast, the monovalent ions exhibit weaker interactions, with Na+ being slightly above Li+, enabling the permeation of Li+ ions. The present study demonstrates the role of both charged groups in cation-exchange membranes in promoting the diffusion of Li+ and Na+ ions, and could serve as a guide for the design of effective membranes for the recovery of these ions from brine.
Using of Amniotic Membrane Derivatives for the Treatment of Chronic Wounds
Authors: Schmiedova Iveta , Dembickaja Alena , Kiselakova Ludmila , Nowakova Beata , Slama Petr
Published: November 2021

Amniotic membrane grafts have some therapeutic potential for wounds healing. Early application of amniotic membrane turned out as beneficial in healing ulcers, burns, and dermal injuries. Since the second half of the 20th century, the autotransplants of amniotic/chorion tissue have been also used for the treatment of chronic neuropathic wounds, cornea surface injuries, pterygium and conjunctivochalasis, and dental and neurosurgical applications. The aim of this publication is to prepare a coherent overview of amniotic membrane derivatives use in the field of wound healing and also its efficacy. In total 60 publications and 39 posters from 2000–2020 were examined. In these examined publications of case studies with known study results was an assemblage of 1141 patients, and from this assemblage 977 were successfully cured. In case of posters, the assemblage is 570 patients and 513 successfully cured. From the investigated data it is clear that the treatment efficacy is very high—86% and 90%, respectively. Based on this information the use of the amniotic membrane for chronic wounds can be considered highly effective.
Investigation of the Extrapolation Capability of an Artificial Neural Network Algorithm in Combination with Process Signals in Resistance Spot Welding of Advanced High-Strength Steels
Authors: El-Sari Bassel , Biegler Max , Rethmeier Michael
Published: November 2021

Resistance spot welding is an established joining process for the production of safety-relevant components in the automotive industry. Therefore, consecutive process monitoring is essential to meet the high quality requirements. Artificial neural networks can be used to evaluate the process parameters and signals, to ensure individual spot weld quality. The predictive accuracy of such algorithms depends on the provided training data set, and the prediction of untrained data is challenging. The aim of this paper was to investigate the extrapolation capability of a multi-layer perceptron model. That means, the predictive performance of the model was tested with data that clearly differed from the training data in terms of material and coating composition. Therefore, three multi-layer perceptron regression models were implemented to predict the nugget diameter from process data. The three models were able to predict the training datasets very well. The models, which were provided with features from the dynamic resistance curve predicted the new dataset better than the model with only process parameters. This study shows the beneficial influence of process signals on the predictive accuracy and robustness of artificial neural network algorithms. Especially, when predicting a data set from outside of the training space.
Understanding the Radiation Resistance Mechanisms of Nanocrystalline Metals from Atomistic Simulation
Authors: Zhang Liang
Published: November 2021

Metallic materials produce various structural defects in the radiation environment, resulting in serious degradation of material properties. An important way to improve the radiation-resistant ability of materials is to give the microstructure of materials a self-healing ability, to eliminate the structural defects. The research and development of new radiation-resistant materials with excellent self-healing ability, based on defects control, is one of the hot topics in materials science. Compared with conventional coarse-grained materials, nanocrystalline metals with a high density of grain boundary (GB) show a higher ability to resist radiation damage. However, the mechanism of GB’s absorption of structural defects under radiation is still unclear, and how to take advantage of the GB properties to improve the radiation resistance of metallic materials remains to be further investigated. In recent decades, atomistic simulation has been widely used to study the radiation responses of different metals and their underlying mechanisms. This paper briefly reviews the progress in studying radiation resistance mechanisms of nanocrystalline metals by employing computational simulation at the atomic scale.
The Effect of Current Supply Duration during Stepwise Electrical Sintering of Silver Nanoparticles
Authors: Lee Iksang , Hussain Arif , Lee Hee-Lak , Moon Yoon-Jae , Hwang Jun-Young , Moon Seung-Jae
Published: November 2021

We studied the effect of current supply duration at final-step currents during the stepwise electrical sintering of silver (Ag) nanoparticles (NPs). Ag NPs ink was inkjet-printed onto Eagle-XG glass substrates. Constant final-step currents of 0.4 and 0.5 A with various time intervals were applied to the printed samples. The final-step current of 0.5 A damaged the line at a comparatively shorter time duration. On the other hand, the lower final-step current of 0.4 A prevented the line damage at longer time durations while producing comparatively lower Ag NPs specific resistance. The minimum specific resistances of the printed samples sintered at 0.4 and 0.5 A were 3.59 μΩ∙cm and 3.79 μΩ∙cm, respectively. Furthermore, numerical temperature estimation and scanning electron microscope (SEM) analysis were conducted to elaborate on the results. The numerical temperature estimation results implied that the lower estimated peak temperature at the final-step current of 0.4 A helped prevent Ag NP line damage. The SEM micrographs suggested that a high surface porosity—caused by higher sintering peak temperatures—in the case of the 0.5 A final-step current resulted in a comparatively higher Ag NP line-specific resistance. This contribution is a step forward in the development of Ag NP sintering for printed electronics applications.
Simultaneous Improvement in Mechanical Properties and Fatigue Crack Propagation Resistance of Low Carbon Offshore Structural Steel EH36 by Cu–Cr Microalloying
Authors: Peng Xingdong , Zhang Peng , Hu Ke , Yan Ling , Li Guanglong
Published: November 2021

Improving the mechanical performance of low-carbon offshore steel is of great significance in shipbuilding applications. In this paper, a new Cu-Cr microalloyed offshore structural steel (FH36) was developed based on EH36. The microstructure, mechanical properties, and fatigue crack propagation properties of rolled plates of FH36, EH36, and normalizing rolled EH36 plates (EH36N) manufactured by a thermo-mechanical control process (TMCP) were analyzed and compared (to simplify, the two rolled specimens are signified by FH36T and EH36T, respectively). FH36T showed an obvious advantage in elongation with the value of 29%, 52.2% higher than the EH36T plates. The normalizing process led to a relatively lower yield stress (338 MPa), but substantially increased the elongation (33%) and lessened the yield ratio from 0.77 to 0.67. Electron back-scattered diffraction (EBSD) analysis showed that SFs of the deformation texture of FH36T and EH36N along the transverse direction (TD) and normal direction (ND) were much higher than those of the EH36T plate, which enhanced the lateral movement ability in the width and thickness direction, enhancing the ductility. Moreover, FH36 plates showed a better fatigue crack propagation resistance than rolled EH36 plates. The formation of the jagged shape grain boundaries is believed to induce a decrease of effective stress intensity factor during the fatigue crack propagation process.
The Grain Boundary Wetting Phenomena in the Ti-Containing High-Entropy Alloys: A Review
Authors: Straumal Boris B. , Korneva Anna , Kuzmin Alexei , Lopez Gabriel A. , Rabkin Eugen , Straumal Alexander B. , Gerstein Gregory , Gornakova Alena S.
Published: November 2021

In this review, the phenomenon of grain boundary (GB) wetting by melt is analyzed for multicomponent alloys without principal components (also called high-entropy alloys or HEAs) containing titanium. GB wetting can be complete or partial. In the former case, the liquid phase forms the continuous layers between solid grains and completely separates them. In the latter case of partial GB wetting, the melt forms the chain of droplets in GBs, with certain non-zero contact angles. The GB wetting phenomenon can be observed in HEAs produced by all solidification-based technologies. GB leads to the appearance of novel GB tie lines Twmin and Twmax in the multicomponent HEA phase diagrams. The so-called grain-boundary engineering of HEAs permits the use of GB wetting to improve the HEAs’ properties or, alternatively, its exclusion if the GB layers of a second phase are detrimental.
Dynamic Simulations of Manufacturing Processes: Hybrid-Evolving Technique
Authors: Horr Amir M. , Kronsteiner Johannes
Published: November 2021

Hybrid physical-data-driven modeling techniques have steadily been developed to address the multi-scale and multi-physical aspects of dynamic process simulations. The analytical and computational features of a new hybrid-evolving technique for these processes are elaborated herein and its industrial applications are highlighted. The authentication of this multi-physical and multi-scale framework is carried out by developing an integrated simulation environment where multiple solver technologies are employed to create a reliable industrial-oriented simulation framework. The goal of this integrated simulation framework is to increase the predictive power of material and process simulations at the industrial scale.
Multi-Level Resistive Switching of Pt/HfO2/TaN Memory Device
Authors: Ryu Hojeong , Jung Hoeje , Lee Kisong , Kim Sungjun
Published: November 2021

This work characterizes resistive switching and neuromorphic simulation of Pt/HfO2/TaN stack as an artificial synaptic device. A stable bipolar resistive switching operation is performed by repetitive DC sweep cycles. Furthermore, endurance (DC 100 cycles) and retention (5000 s) are demonstrated for reliable resistive operation. Low-resistance and high-resistance states follow the Ohmic conduction and Poole–Frenkel emission, respectively, which is verified through the fitting process. For practical operation, the set and reset processes are performed through pulses. Further, potentiation and depression are demonstrated for neuromorphic application. Finally, neuromorphic system simulation is performed through a neural network for pattern recognition accuracy of the Fashion Modified National Institute of Standards and Technology dataset.
Tailoring the Austenite Fraction of a Cu and Ni Containing Medium-Mn Steel via Warm Rolling
Authors: Xu Zigan , Li Jiyao , Shen Xiao , Allam Tarek , Richter Silvia , Song Wenwen , Bleck Wolfgang
Published: November 2021

Developing medium-Mn steels (MMnS) demands a better understanding of the microstructure evolution during thermo-mechanical treatments (TMTs). This study demonstrates the relationship among processing, microstructure, and mechanical properties of a warm-rolled medium-Mn steel (MMnS) containing 1.5 wt. % Cu and 1.5 wt. % Ni. After short-time warm rolling (WR) in an intercritical temperature range, a significant quantity (40.6 vol.%) of austenite was reverted and retained after air cooling. The microstructure and tensile properties of the WR specimens were compared with two typical process routes, namely hot rolling+ cold rolling+ annealing+ tempering (CRAT) and warm rolling+ annealing+ tempering (WRAT). The WR specimen exhibited comparable tensile properties with the CRAT specimens (967 MPa yield strength, 1155 MPa tensile strength, 23% total elongation), with a remarkably shortened process route, which was derived from the dislocation accumulation and austenite reversion during rolling. The WR route stands out among the traditional CRAT and the extended WRAT routes for its excellent tensile properties and compact processing route.
Advanced Trends in Metallurgy and Weldability of High-Strength Cold-Resistant and Cryogenic Steels
Authors: Rudskoi Andrei I. , Parshin Sergey G.
Published: November 2021

Thermomechanical Controlled Processing (TMCP), the initial microstructure and mechanical properties of rolled products made of high-strength steels, have a significant influence on the properties and reliability of welded structures for low temperature and cryogenic service. This paper systematizes advanced research trends in the field of metallurgy and weldability of high-strength cold-resistant and cryogenic steels. The classification and properties of high-strength steels are given and TMCP diagrams and phase transformations are considered. Modern methods of improving the viscoplasticity of rolled steel and welded joints are analyzed. The problems of the weldability of high-strength steels are reduction of impact toughness at low temperatures, hydrogen embrittlement, anisotropy, and softening of welded joints in the heat-affected zone. The authors propose a systemic concept and methods for improving the metallurgy and weldability of high-strength steels for low temperature and cryogenic service.
Permeability Measurements of 3D Microstructures Generated by Phase Field Simulation of the Solidification of an Al-Si Alloy during Chill Casting
Authors: Berger Ralf , Apel Markus , Laschet Gottfried , Jessen Wilhelm , Schröder Wolfgang , Wipperfürth Jens , Austermann Johannes , Hopmann Christian
Published: November 2021

The permeability of the semi-solid state is important for the compensation of volume shrinkage during solidification, since insufficient melt feeding can cause casting defects such as hot cracks or pores. Direct measurement of permeability during the dynamical evolution of solidification structures is almost impossible, and numerical simulations are the best way to obtain quantitative values. Equiaxed solidification of the Al-Si-Mg alloy A356 was simulated on the microscopic scale using the phase field method. Simulated 3D solidification structures for different stages along the solidification path were digitally processed and scaled up to generate 3D models by additive manufacturing via fused filament fabrication (FFF). The Darcy permeability of these models was determined by measuring the flow rate and the pressure drop using glycerol as a model fluid. The main focus of this work is a comparison of the measured permeability to results from computational fluid flow simulations in the phase field framework. In particular, the effect of the geometrical constraint due to isolated domain walls in a unit cell with a periodic microstructure is discussed. A novel method to minimize this effect is presented. For permeability values varying by more than two orders of magnitude, the largest deviation between measured and simulated permeabilities is less than a factor of two.
Upscaling Severe Torrefaction of Agricultural Residues to Produce Sustainable Reducing Agents for Non-Ferrous Metallurgy
Authors: Demey Hary , Rodriguez-Alonso Elvira , Lacombe Elie , Grateau Maguelone , Jaricot Nicolas , Chatroux André , Thiery Sebastien , Marchand Muriel , Melkior Thierry
Published: November 2021

Torrefaction of almond shells and olive stones, which are typically considered agricultural waste in the southern regions of the European Union, was investigated in this work for application as reducing agents in the metallurgical industry. Four different temperatures were tested: 250, 280, 300 and 350 °C. The evolution of the solid yields with the temperature was determined with TGA measurements. This showed that the duration of torrefaction should not exceed 45 min. The kinetic profiles were successfully fitted using the pseudo-first-order rate equation (PFORE). Then, torrefaction for 45 min was systematically carried out at every temperature and for each resource in a laboratory-scale batch device. The raw and torrefied biomasses were characterized using proximate, ultimate and calorific analyses. The carbon/oxygen ratio and the heating values were increased as a result of the torrefaction severity (from 20 MJ/kg for both raw biomasses to 30 MJ/kg at 350 °C). The highest mass losses were obtained at the highest temperature (67.35 and 65.04 %w for almond shells and olive stones, respectively, at 350 °C). The fixed carbon value also increased, being higher than 67 %w for torrefaction at 350 °C. The large-scale torrefaction at 350 °C (45 min) of these biomasses was carried out in a continuous pilot plant. The solids were characterized as well, and their properties were close to those of the biomasses torrefied in the laboratory-scale batch reactor under the same conditions. This thermal treatment provided biochars with all the required properties to be used as reducing materials in metallurgy.
Response of Floc Networks in Cemented Paste Backfill to a Pumping Agent
Authors: Zhu Jiaqi , Wu Shunchuan , Cheng Haiyong , Geng Xiaojie , Liu Jin
Published: November 2021

Cemented paste backfill is critical for the development of green mines, the safe exploitation of mineral resources deep underground, and the efficient disposal of solid wastes produced by mining. In this paper, the mechanism underpinning how the pumping agent works was studied. The number, area, and fractal dimension of pores in the microstructure of fresh paste were quantitatively analyzed using scanning electron microscopy (SEM), image processing, and fractal theory, and the response of flocs was investigated. The results show that floc networks disintegrated and the liquid network became the dominant structure under the action of the pumping agent, which enhanced the lubrication and promotion of multi-scale particles. In addition, the force chains became fragile and scattered, diminishing the yield stress of the paste. The pores had a more homogenized dimension and the porosity was 15.52% higher. The increase in the fractal dimension of the pores indicated that there was a higher self-similarity, in terms of microstructure, with a strengthened liquid network. The migration of floc structures contributed to the enhancement of the fluidity and rheology of the paste. This study provides insights into the effects of floc and liquid networks on the performance of paste, and it is of engineering significance in terms of realizing safe and efficient CPB operations.
Solid Solution Strengthening of Mo, Re, Ta and W in Ni during High-Temperature Creep
Authors: Haußmann Lukas , ur Rehman Hamad ur , Matschkal Dorothea , Göken Mathias , Neumeier Steffen
Published: November 2021

Solid solution strengthening of the unordered γ matrix phase by alloying elements is of great importance during creep of Ni-based superalloys, particularly at high temperatures above 1000 °C. To study the role of different potent solutes, we have conducted creep experiments on binary Ni-2X alloys (X = Mo, Re, Ta, W) at 1000 °C, 1050 °C, and 1100 °C at a constant stress of 20 MPa. Compared to mechanical tests below 800 °C, where the size of the elements mostly determines the solid solution hardening contribution, the strengthening contribution of the different alloying elements above 1000 °C directly correlates with their diffusivity. Therefore, elements such as Ta that lead to strong solid solution hardening at low temperatures become less effective at higher temperatures and are exceeded by slower diffusing elements, such as Re.
The Effect of Silica Sand Proportion in Laser Scabbling Process on Cement Mortar
Authors: Huynh Tam-Van , Seo Youngjin , Lee Dongkyoung
Published: November 2021

Cement mortar composite has a wide range of applications on construction sites, including masonry, plastering and concrete repair. In construction sites, scabbling process is a method to remove from a few millimeters to several centimeters of defect concrete surfaces. As a result, it is essential to investigate the scabbling characteristics for cement mortar with different silica sand proportion in laser scabbling process. In this study, 5 types of cement mortar with different silica sand proportions in mixing were fabricated and scabbled by using a high-density power laser beam. The effects of silica sand proportion in color changing and penetration depth of the samples after laser scabbling process were studied. Furthermore, the generation of micro-cracks and pores were observed by using scanning electron microscopy (SEM). In addition, chemical composition changes between processed zone and non-processed zone were also evaluated by Energy Dispersive X-ray (EDX) analysis. The results of this study are expected to provide valuable knowledge in understanding of the laser scabbling process for cement-based materials.
High-Pressure Cooling in Finishing Turning of Haynes 282 Using Carbide Tools: Haynes 282 and Inconel 718 Comparison
Authors: Díaz-Álvarez Antonio , Díaz-Álvarez José , Cantero José Luis , Miguélez María Henar
Published: November 2021

Despite the interest of industry in nickel-based superalloys and its main features (high temperatures resistance, hardness, low thermal conductivity, among others), even today they are still materials that are difficult to cut. Cutting tools withstand both high pressures and temperatures highly localized at the cutting area because of the elevated work hardening of the alloy and the problems for the cutting fluid to access the region, with the consequent strong tool wear. The use of cutting fluids at high pressures improves coolant access and heat removal. This paper analyzed the machining of Haynes 282 alloy by means of coated carbide tools under high-pressure cutting fluids at finishing conditions. Tests were developed at different cutting speeds and feeds quantifying the machining forces, surface roughness, tool wear, and tool life. Values of 45.9 min and Ra between 2 µm and 1 µm were obtained in this study for tool life and roughness, respectively, for the combination of cutting speed 50 m/min and feed 0.1 mm/rev. Likewise, a comparative analysis is included with the results obtained in previous works developed by the authors relating to the finishing turning of Haynes 282 and Inconel 718 under conventional pressure cooling. The comparative analysis with Inconel 718 is included in the study due to its importance within the nickel base superalloys being widely used in industry and widely analyzed in scientific literature.
Critical Assessment of the Electric Effect in Electric Arc Welding
Authors: Qin Rongshan
Published: November 2021

This work provides a critical assessment of electric effects on the microstructure evolution at the heat-affected zone in electric arc welding. Electric effects are the interactions between electromagnetic fields and materials’ microstructures. They differ from the arc effect and the Joule heating effect by providing an alternative contribution to nucleation, grain growth, recrystallisation and tempering. The influence of the electric effect on grain size, defects, anisotropic properties, precipitates and residual stress has been examined kinetically and thermodynamically. The use of adaptable electric current densities, pulse durations, pulse frequencies and electrode movements is suggested to achieve desirable microstructures and mechanical properties for the weldments.
Production and Characterization of a 316L Stainless Steel/β-TCP Biocomposite Using the Functionally Graded Materials (FGMs) Technique for Dental and Orthopedic Applications
Authors: Kuffner Bruna Horta Bastos , Capellato Patricia , Ribeiro Larissa Mayra Silva , Sachs Daniela , Silva Gilbert
Published: November 2021

Metallic biomaterials are widely used for implants and dental and orthopedic applications due to their good mechanical properties. Among all these materials, 316L stainless steel has gained special attention, because of its good characteristics as an implantable biomaterial. However, the Young’s modulus of this metal is much higher than that of human bone (~193 GPa compared to 5–30 GPa). Thus, a stress shielding effect can occur, leading the implant to fail. In addition, due to this difference, the bond between implant and surrounding tissue is weak. Already, calcium phosphate ceramics, such as beta-tricalcium phosphate, have shown excellent osteoconductive and osteoinductive properties. However, they present low mechanical strength. For this reason, this study aimed to combine 316L stainless steel with the beta-tricalcium phosphate ceramic (β-TCP), with the objective of improving the steel’s biological performance and the ceramic’s mechanical strength. The 316L stainless steel/β-TCP biocomposites were produced using powder metallurgy and functionally graded materials (FGMs) techniques. Initially, β-TCP was obtained by solid-state reaction using powders of calcium carbonate and calcium phosphate. The forerunner materials were analyzed microstructurally. Pure 316L stainless steel and β-TCP were individually submitted to temperature tests (1000 and 1100 °C) to determine the best condition. Blended compositions used to obtain the FGMs were defined as 20% to 20%. They were homogenized in a high-energy ball mill, uniaxially pressed, sintered and analyzed microstructurally and mechanically. The results indicated that 1100 °C/2 h was the best sintering condition, for both 316L stainless steel and β-TCP. For all individual compositions and the FGM composite, the parameters used for pressing and sintering were appropriate to produce samples with good microstructural and mechanical properties. Wettability and hemocompatibility were also achieved efficiently, with no presence of contaminants. All results indicated that the production of 316L stainless steel/β-TCP FGMs through PM is viable for dental and orthopedic purposes.
Development of Ultrafine Grain IF Steel via Differential Speed Rolling Technique
Authors: Ko Young Gun , Hamad Kotiba
Published: November 2021

The aim of this paper was to investigate the microstructural development and properties of interstitial free (IF) steel fabricated using the DSR (differential speed rolling) process. Severe plastic deformation of the DSR passes was imposed on the sample for up to four passes, leading to ~1.7 total strain with a speed ratio of 1:4 between the two rolls. Microstructural observation revealed that the equiaxed grain size of ~0.7 µm, including the formation of grain boundaries with a high angle of misorientation, was reached after four operations of DSR, which was attributed to the grain subdivision of severely elongated ferrite grain. Since the deformation mode of the DSR operation was dominated by severe shear deformation, the main shear texture of the bcc components appeared in all DSR operations in which the α-fiber of the {110} slip became a main component in accommodating the severe plastic deformation of the DSR process. The intensity of the shear texture, the {110} and {112} slip, increased by increasing the number of passes. Moreover, the γ-fiber of the <112>-type planes was activated as a result of the alternation of the shear direction during sample rotation. The microhardness and room temperature tensile tests revealed that the strength of the IF steel improved as the amount of strain increased, and this was attributed to the grain refinement and texture characteristics of the samples after the DSR processing.
The Effect of a Slow Strain Rate on the Stress Corrosion Resistance of Austenitic Stainless Steel Produced by the Wire Laser Additive Manufacturing Process
Authors: Bassis Maxim , Kotliar Abram , Koltiar Rony , Ron Tomer , Leon Avi , Shirizly Amnon , Aghion Eli
Published: November 2021

The wire laser additive manufacturing (WLAM) process is considered a direct-energy deposition method that aims at addressing the need to produce large components having relatively simple geometrics at an affordable cost. This additive manufacturing (AM) process uses wires as raw materials instead of powders and is capable of reaching a deposition rate of up to 3 kg/h, compared with only 0.1 kg/h with common powder bed fusion (PBF) processes. Despite the attractiveness of the WLAM process, there has been only limited research on this technique. In particular, the stress corrosion properties of components produced by this technology have not been the subject of much study. The current study aims at evaluating the effect of a slow strain rate on the stress corrosion resistance of 316L stainless steel produced by the WLAM process in comparison with its counterpart: AISI 316L alloy. Microstructure examination was carried out using optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction analysis, while the mechanical properties were evaluated using tensile strength and hardness measurements. The general corrosion resistance was examined by potentiodynamic polarization and impedance spectroscopy analysis, while the stress corrosion performance was assessed by slow strain rate testing (SSRT) in a 3.5% NaCl solution at ambient temperature. The attained results highlight the inferior mechanical properties, corrosion resistance and stress corrosion performance, especially at a slow strain rate, of the WLAM samples compared with the regular AISI 316L alloy. The differences between the WLAM alloy and AISI 316L alloy were mainly attributed to their dissimilarities in terms of phase compositions, structural morphology and inherent defects.
Numerical and Non-Destructive Analysis of an Aluminum-CFRP Hybrid 3D Structure
Authors: Silva Leandro Soares , Fernandes Henrique , Schwarz Michael , Herrmann Hans-Georg , Cavalini Aldemir
Published: November 2021

Advanced materials are widely used in many industries. They play an important role especially in the aeronautic and automotive sectors where weight reduction is required in order to reduce fuel consumption. Composite materials have a high strength to weight ratio and are applied in airplane construction. Nevertheless, sometimes it is not viable to replace all metal parts by composite ones due to the cost factor. In this sense, hybrid structures are highly welcome. In order to ensure the safety of these hybrid components during their entire life cycle, non-destructive testing evaluation (NDT&E) methods are used and sometimes they are the only option. In this study, we use infrared thermography (IRT) to inspect an aluminum-composite hybrid structure with a 3D shape. The sample has a composite part with a small metal inlay (EN AW-6082) overmolded with a thermoplastic layer. The inlay is bended to reach the desired 3D geometry. This sample was design to be used for the connection between an A- or B-pillar and a car roof made of carbon fiber reinforced polymer (CFRP). A dual-band infrared camera is used in order to capture images in two different spectral ranges. In addition, two data processing techniques for infrared images are applied to enhance the images: principal component thermography (PCT) and partial least squares thermography (PLST). Then, a signal-to-noise ratio analysis is performed with three randomly chosen previous known defects to assess the quality of the images and detected defects. Results showed that principal component thermography has a slight advantage over partial least squares thermography in our specific experiments. Specifically, for the long-wave infrared band, PCT presented, among the defects analyzed, PCT presented a mean value 12.5% higher while the standard deviation was almost three times lower than PLST. In parallel to the non-detructive analysis, a numerical finite element model was formulated in ANSYS® to analyze the total deformations to which the metal-composite-hybrid structure is subjected during a possible use. Results obtained with the numerical model indicate that the interface region between composite and metal parts is where the highest degree of deformation occur, which indicates possible regions where defects and failures may occur in real use cases.
β-Cell Death in Diabetes: Past Discoveries, Present Understanding, and Potential Future Advances
Authors: Mukherjee Noyonika , Lin Li , Contreras Christopher J. , Templin Andrew T.
Published: November 2021

β-cell death is regarded as a major event driving loss of insulin secretion and hyperglycemia in both type 1 and type 2 diabetes mellitus. In this review, we explore past, present, and potential future advances in our understanding of the mechanisms that promote β-cell death in diabetes, with a focus on the primary literature. We first review discoveries of insulin insufficiency, β-cell loss, and β-cell death in human diabetes. We discuss findings in humans and mouse models of diabetes related to autoimmune-associated β-cell loss and the roles of autoreactive T cells, B cells, and the β cell itself in this process. We review discoveries of the molecular mechanisms that underlie β-cell death-inducing stimuli, including proinflammatory cytokines, islet amyloid formation, ER stress, oxidative stress, glucotoxicity, and lipotoxicity. Finally, we explore recent perspectives on β-cell death in diabetes, including: (1) the role of the β cell in its own demise, (2) methods and terminology for identifying diverse mechanisms of β-cell death, and (3) whether non-canonical forms of β-cell death, such as regulated necrosis, contribute to islet inflammation and β-cell loss in diabetes. We believe new perspectives on the mechanisms of β-cell death in diabetes will provide a better understanding of this pathological process and may lead to new therapeutic strategies to protect β cells in the setting of diabetes.
A Core Metabolome Response of Maize Leaves Subjected to Long-Duration Abiotic Stresses
Authors: Joshi Jaya , Hasnain Ghulam , Logue Taylor , Lynch Madeline , Wu Shan , Guan Jiahn-Chou , Alseekh Saleh , Fernie Alisdair R. , Hanson Andrew D. , McCarty Donald R.
Published: November 2021

Abiotic stresses reduce crop growth and yield in part by disrupting metabolic homeostasis and triggering responses that change the metabolome. Experiments designed to understand the mechanisms underlying these metabolomic responses have usually not used agriculturally relevant stress regimes. We therefore subjected maize plants to drought, salt, or heat stresses that mimic field conditions and analyzed leaf responses at metabolome and transcriptome levels. Shared features of stress metabolomes included synthesis of raffinose, a compatible solute implicated in tolerance to dehydration. In addition, a marked accumulation of amino acids including proline, arginine, and γ-aminobutyrate combined with depletion of key glycolysis and tricarboxylic acid cycle intermediates indicated a shift in balance of carbon and nitrogen metabolism in stressed leaves. Involvement of the γ-aminobutyrate shunt in this process is consistent with its previously proposed role as a workaround for stress-induced thiamin-deficiency. Although convergent metabolome shifts were correlated with gene expression changes in affected pathways, patterns of differential gene regulation induced by the three stresses indicated distinct signaling mechanisms highlighting the plasticity of plant metabolic responses to abiotic stress.
AMPK-Mediated Metabolic Switching Is High Effective for Phytochemical Levo-Tetrahydropalmatine (l-THP) to Reduce Hepatocellular Carcinoma Tumor Growth
Authors: Yin Xunzhe , Li Wenbo , Zhang Jiaxin , Zhao Wenjing , Cai Huaxing , Zhang Chi , Liu Zuojia , Guo Yan , Wang Jin
Published: November 2021

Targeting cancer cell metabolism has been an attractive approach for cancer treatment. However, the role of metabolic alternation in cancer is still unknown whether it functions as a tumor promoter or suppressor. Applying the cancer gene-metabolism integrative network model, we predict adenosine monophosphate-activated protein kinase (AMPK) to function as a central hub of metabolic landscape switching in specific liver cancer subtypes. For the first time, we demonstrate that the phytochemical levo-tetrahydropalmatine (l-THP), a Corydalis yanhusuo-derived clinical drug, as an AMPK activator via autophagy-mediated metabolic switching could kill the hepatocellular carcinoma HepG2 cells. Mechanistically, l-THP promotes the autophagic response by activating the AMPK-mTOR-ULK1 and the ROS-JNK-ATG cascades and impairing the ERK/AKT signaling. All these processes ultimately synergize to induce the decreased mitochondrial oxidative phosphorylation (OXPHOS) and mitochondrial damage. Notably, silencing AMPK significantly inhibits the autophagic flux and recovers the decreased OXPHOS metabolism, which results in HepG2 resistance to l-THP treatment. More importantly, l-THP potently reduces the growth of xenograft HepG2 tumor in nude mice without affecting other organs. From this perspective, our findings support the conclusion that metabolic change is an alternative approach to influence the development of HCC.