bluuebunny/crossref_metadata_2025 huggingface dataset:
Response of Bilayer and Trilayer Graphene to High-Energy Heavy Ion Irradiation
Authors: Iveković Damjan , Kumar Sunil , Gajović Andrea , Čižmar Tihana , Karlušić Marko
Published: February 2023

High-energy heavy ion irradiation is a very useful tool for the nanostructuring of 2D materials because defects can be introduced in a controlled way. This approach is especially attractive for the mass production of graphene nanomembranes when nanopore size and density can easily be tuned by ion irradiation parameters such as ion energy and applied fluence. Therefore, understanding the basic mechanisms in nanopore formation due to high-energy heavy ion impact is of the highest importance. In the present work, we used Raman spectroscopy to investigate the response of bilayer and trilayer graphene to this type of irradiation. Spectra obtained from graphene samples irradiated with 1.8 MeV I, 23 MeV I, 3 MeV Cu, 18 MeV Cu, and 12 MeV Si beams were analysed using the Lucchese model. It was found that the efficiency of damage production scales strongly with nuclear energy loss. Therefore, even for the most energetic 23 MeV I beam, the electronic energy loss does not contribute much to damage formation and ion tracks are unlikely to be formed.
Polyphenols Coordinated with Cu (II) in an Aqueous System Build Ion-Channel Coatings on Hair Surfaces
Authors: Jin Lei , Yun Daemyoung , Zhang Wei , Lee Jinsung , Shin Hongchul , Kim Donghyuk , Kang Tae-Bong , Won Hyung-Sik , Jang Hohyoun , Kim Whangi
Published: February 2023

Recently, developments in the field of cosmetics have led to a renewed interest in hair dyeing. However, damage to the hair during the dyeing process has increased hesitation in attempting hair dyeing. As a result, hair dyes with minimal side effects have been in constant demand, and are being developed. In this study, natural-extract polyphenols, pyrogallol, and gallic acid are coordinated by CuCl2 in a NaCl aqueous solution to form an oligomer, which creates an ion-channel coating on the hair surface to protect it. This work attempts to develop fast, simple, and damage-free hair-dye ingredients based on pyrogallol and gallic acid. The morphology and elements of polyphenols coated on hair are characterized. The results reveal that the hair is dyed with the polyphenol-based dye reagent successfully. Moreover, the thickness of the dyed hair continuously rises ten times after dyeing. The tensile strength of the dyed hair is also measured, showing an upward and downward trend. These results reflect the fact that pyrogallol and gallic acid are considered to be the essential and functional polyphenols, and can build ion blocks on hair, which can create new multifunctional coating materials.
Effect of Post-Weld Heat Treatment on Microstructure and Hardness of Laser Beam Welded 17-4 PH Stainless Steel
Authors: Tuz Lechosław , Sokołowski Łukasz , Stano Sebastian
Published: February 2023

This article presents the results of research on the development of the technology of laser beam butt welding of 17-4 PH stainless steel sheets and the technology of post-weld heat treatment (PWHT). The developed technology allows for favorable conditions to be obtained and for the appropriate microstructure and hardness to exist in the weld area. Moreover, it enables the fulfillment of a number of specific requirements beyond the possibilities of manual welding and other methods. The tests performed include the analysis of the microstructure with the use of light microscopy (LM) for the materials after welding and PWHT. The applied PWHT showed changes in the microstructure and mechanical properties. In all weld areas the martensitic microstructure was observed. The homogeneity of the microstructure in the area of the welded joint after PWTH was revealed. In the as-welded condition and after the PWHT with aging at 481 °C, the hardness was 440 HV5, but after aging at 621 °C, it decreased to 330–340 HV5.
Synthesis of Micro- and Mesoporous Carbon Foams with Nanodispersed Metals for Adsorption and Catalysis Applications
Authors: García Roberto , Rodríguez Elena , Díez María A. , Arenillas Ana , Villanueva Sara F. , Rey-Raap Natalia , Cuesta Cristóbal , López-Antón María A. , Martínez-Tarazona M. Rosa
Published: February 2023

This work focuses on carbon foams, whose peculiarity is a predominant open macroporous cellular network that can be provided with tailored texture and morphology by the modification of the preparation process. The goal was to obtain macroporous carbonaceous structures capable of being activated by following a simple thermo-foaming procedure using a few reagents. With this purpose in mind, carbon foams with different textural properties were synthesized from sucrose using two foaming processes: at atmospheric pressure and in a pressurized reactor. Iron and silver nitrates added to sucrose gave rise, after carbonization, to materials with iron oxides and elemental silver particles nano-dispersed in the carbon matrix and promoted microporosity in both cases and mesoporosity in the case of iron nitrate. Iron nitrate also catalyzes the graphitization of the carbon material during carbonization. All these findings show the potential of sucrose thermo-foaming process as a viable and sustainable path to produce versatile carbon materials, capable of being used in various applications.
The Influence of Fly Ash on the Tensile Creep Prediction of High-Strength Concrete at Early Ages
Authors: Yao Jikai , Yao Shuifeng , Huang Senle , Ni Tongyuan , Jiang Chenhui , Yang Yang , Kong Deyu
Published: February 2023

In this study, the tensile creep (TC) of high-strength concrete (HSC) containing 30 wt% fly ash was measured at early ages to investigate the applicability of creep prediction models for concrete containing FA, and to provide ideas to study the prediction model of concrete creep containing other SCMs in the future. The TC values obtained from the experiment were compared with the predicted values of six TC models. Then the accuracy of different models was evaluated by the ratio of predicted values to experimental values. Finally, the applicability of these models to the TC of HSC with fly ash was discussed at an early age. By comparison, it was found that when the loading age was 1d, 2d, and 3d, the ZC model (ZC are the initials for the word “Self-developed” in Chinese), which is a rheology-based model for TC, proposed by Yang.Y et al. agreed with the experimental values. The predicted values of the other five models deviated significantly from the tested ones. When the loading age was 5d and 7d, the calculated results of the ACI 2009R model were more accurate. Compared with the other five models, the time dependency of the paste with fly ash was considered in the ZC model, and parameter q of the ZC model was introduced in order to characterize the influence of fly ash on the paste at early ages. Therefore, this paper demonstrated both theoretically and experimentally that the ZC model can better predict the early-age TC of HSC with fly ash.
Comparative Study of the Magnetic Behavior of FINEMET Thin Magnetic Wires: Glass-Coated, Glass-Removed, and Cold-Drawn
Authors: Corodeanu Sorin , Hlenschi Costică , Chiriac Horia , Óvári Tibor-Adrian , Lupu Nicoleta
Published: February 2023

In this paper, a comparative investigation of the magnetic behavior and its stress dependence in the case of FINEMET glass-coated, glass-removed, and cold-drawn microwires at low and high frequencies, respectively, is presented. The experimental results show major differences between their magnetic properties depending on the preparation method and microwire diameter. The evolution of the magnetic permeability, coercivity, and magnetoimpedance responses with the applied tensile force was investigated and analyzed in correlation with the stresses induced during preparation, their relief following annealing, and the annealing-induced structural transformations. The coercivity dependence on applied force was found to show the highest sensitivity in the glass-removed microwires, while the magnetic permeability and magnetoimpedance sensitivity to force were found to be higher in the cold-drawn samples. The results of this comparative study will enable an enhanced material selection process for various applications in miniaturized magnetic and stress sensors with increased sensitivity.
Review on Performance of Asphalt and Asphalt Mixture with Waste Cooking Oil
Authors: Luo Yaofei , Zhang Ke
Published: February 2023

To make full use of the regenerative value of waste cooking oil, and to solve the environmental pollution and food security issues caused by waste cooking oil, waste cooking oil was suggested for use in asphalt. Waste cooking oil was used to adjust the performance of virgin and aged asphalt. This review article summarizes research progress on the performance of asphalt and asphalt mixture with waste cooking oil. The results showed that a moderate dosage of waste cooking oil will improved the low-temperature performance and construction workability of petroleum asphalt and aged asphalt. The mixing and compaction temperature of asphalt mixture with waste cooking oil are reduced by up to 15 °C. The rutting resistance and fatigue resistance of modified asphalt and modified asphalt mixture with waste cooking oil are damaged. After the addition of waste cooking oil in aged asphalt, the high-temperature performance and shear rheologic property of aged asphalt will be recovered. The regeneration effect of waste cooking oil on aged asphalt and aged asphalt mixture is close to that of a traditional regeneration agent, and the partial performance of asphalt or asphalt mixture with waste cooking oil is better. There is no chemical reaction between waste cooking oil and asphalt, but the asphalt component and absorption peak intensity of partial functional groups are changed. The light components content of asphalt binder is usually increased. Further research regarding the engineering application of asphalt mixture with waste cooking oil should be conducted. The method for improving the performance of asphalt and asphalt mixture with waste cooking oil will be mainly researched.
Influence of the Addition of Alumina Nanofibers on the Strength of Epoxy Resins
Authors: Simunin M. M. , Voronin A. S. , Fadeev Yu. V. , Dobrosmyslov S. S. , Kuular A. A. , Shalygina T. A. , Shabanova K. A. , Chirkov D. Yu. , Voronina S. Yu. , Khartov S. V.
Published: February 2023

The paper describes the effect of the addition of alumina nanofibers on the mechanical properties of the epoxy resin. Alumina nanofibers functionalized with epoxypropyl functional groups are used in this work. The dependence of the mechanical characteristics on the amount of the additive, as well as the features of its distribution in the material, is investigated. In the work, nanocomposites were obtained, which are epoxy resin with aluminum oxide nanofibers. The mechanical properties of the samples were studied by bending tests and differential mechanical analysis (DMA). It has been shown that the addition of alumina nanofibers leads to an increase in ultimate flexural strength. The maximum of this increase is near the percolation threshold of alumina nanofibers in epoxy resin. With the addition of 0.2% alumina nanofibers, the ultimate flexural strength increases from 41 to 71 MPa. It is shown that after exceeding the percolation threshold of nanofibers, the ultimate strength decreases. In this case, the elastic modulus increases from 0.643 to 0.862 GPa. DMA is shown that the glass transition temperature decreases with increasing amount of the additive. This indicates a decrease in the molecular weight of the polymer. By implication, this suggests that the hardener connects the epoxypropyl functional groups on the nanofibers and the epoxy groups in the resin, and as a result of this process, the nanofibers become natural polymer chain length limiters. The data obtained from mechanical testing and differential mechanical analysis can be used to strengthen epoxy resins in polymer composite materials and molding compositions.
Molecular Dynamics Simulation of Ti Metal Cutting Using a TiN:Ag Self-Lubricating Coated Tool
Authors: Lenzi Veniero , Marques Luís
Published: February 2023

Silver-ceramic nanocomposite coatings, such as TiN:Ag, are among the most interesting solutions to improve the machining and cutting process of hard-to-cut Ti alloys, since they combine the TiN matrix hardness with the lubricating and protective action of Ag nanoparticles. Therefore, it is important to understand how, when present, Ag distributes at the tool-workpiece interface and how it affects the tribolayer formation and the tool wear. Molecular dynamics simulation results, obtained using a MEAM-based force field, are presented here for the cutting process of a Ti workpiece with a TiN tool, with and without the presence of Ag at the interface, for different cutting speeds. Ag is shown to form a thin protective layer at the workpiece-tool interface that prevents a direct contact between the parts and greatly reduces the tool degradation. Our simulations confirm the importance of Ag in self-lubricating nanocomposite coatings to realize the machining of otherwise hard-to-cut materials.
Elastic Critical Resistance of the Simple Beam Grillage Resulting from the Lateral Torsional Buckling Condition: FEM Modelling and Analytical Considerations
Authors: Piotrowski Rafał , Szychowski Andrzej , Vičan Josef
Published: February 2023

Transversely loaded beam grillages are quite often used in industrial construction. In order to produce a safe design of such structures, it is necessary to account for the lateral torsional buckling phenomenon, which reduces load-bearing capacity. To be able to calculate the relevant reduction factor, the elastic critical load must be determined. As regards the existing design practice for such structures, simplified conditions are assumed for the mutual restraint of the component beams. However, this approach does not correspond to reality. This study discusses the results of numerical investigations and analytical calculations concerning the effect of the elastic action of simple beam grillage (SBG) joints on the critical load, which results from the lateral torsional buckling (LTB) condition. The SBG was defined as a flat system of interconnected beams, unstiffened laterally and loaded perpendicularly to the grillage plane. The analysis covered H-shaped grillages with different span ratios of component beams, in which the main (coupling) beam was decisive for instability. The effectiveness of the use of closed-section stiffeners at the grillage joints was also investigated. The grillage elastic critical resistances (ECR) were determined for two variants of joint stiffening. The computations were performed by means of FEM numerical simulations. The spatial models were discretised with the following elements: (1) solid ones in Abaqus, (2) shell ones in ConSteel, and (3) thin-walled bars in ConSteel. The LTB critical moments of the weakest beam (critical beam), elastically restrained against warping and against lateral rotation (in the LTB plane), were computed using the analytical methods developed by the authors. To this end, the methods were proposed to determine the indexes of the critical beam elastic restraint in the adjacent stiffening beams. In the study, it was demonstrated that (1) taking into account the conditions of mutual elastic restraint and interaction of the component beams provides a more accurate assessment of the grillage ECR, (2) the use of closed-section stiffeners in the grillage joints increase the ECR compared with classic flat stiffeners, (3) the grillage ECR can be estimated based on the critical moment Mcr of the weakest beam (critical beam) when the conditions of its elastic restraint in joints are accounted for.
Direct Recycling of WC-Co Grinding Chip
Authors: Pacini Alessio , Lupi Francesco , Rossi Andrea , Seggiani Maurizia , Lanzetta Michele
Published: February 2023

Grinding is a finishing process for high precision, high surface quality parts, and hard materials, including tool fabrication and sharpening. The recycling of grinding scraps, which often contain rare and costly materials such as tungsten carbide (WC-Co), has been established for decades. However, there is a growing need for more energy-efficient and environmentally friendly recycling processes. Currently, grinding sludges, which are a mixture of abrasives, lubricants, and hard metal chips, are only treated through chemical recycling. Direct recycling (“reuse” of chips as raw material) is the most effective but not yet viable process due to the presence of contaminants. This paper presents an oil-free dry grinding process that produces high-quality chips (i.e., oil-free and with few contaminants, smaller than 60 mesh particle size) that can be directly recycled, as opposed to the oil-based wet grinding that generates sludges, which require indirect recycling. The proposed alternative recycling method is validated experimentally using WC-Co chips from a leading hard metals’ processing specialized company. The contaminant level (oxygen 0.8 wt.%, others < 0.4 wt.%), granulometry (chip D50 = 10.4 µm with grain size < 3 µm) and morphology of the recycled chips’ powder is comparable to commercial powders proving the research and industrial potential of direct recycling. The comparison of sintered products using recycled and commercial powder provided equivalent characteristics for hardness (HRA of 90.7, HV30 of 1430), porosity grade (A02-04) and grain size (<3 µm).
Properties of TiAlN Coatings Obtained by Dual-HiPIMS with Short Pulses
Authors: Grenadyorov Alexander , Oskirko Vladimir , Zakharov Alexander , Oskomov Konstantin , Rabotkin Sergey , Semenov Vyacheslav , Solovyev Andrey , Shmakov Alexander
Published: February 2023

The paper focuses on the dual high-power impulse magnetron sputtering of TiAlN coatings using short pulses of high power delivered to the target. The surface morphology, elemental composition, phase composition, hardness, wear resistance, and adhesive strength of TiAlN coatings with different Al contents were investigated on WC–Co substrates. The heat resistance of the TiAlN coating was determined with synchrotron X-ray diffraction. The hardness of the TiAlN coating with a low Al content ranged from 17 to 30 GPa, and its wear rate varied between 1.8∙10−6 and 4.9∙10−6 mm3·N−1·m−1 depending on the substrate bias voltage. The HF1–HF2 adhesion strength of the TiAlN coatings was evaluated with the Daimler–Benz Rockwell C test. The hardness and wear rate of the Ti0.61Al0.39N coating were 26.5 GPa and 5.2∙10−6 mm3·N−1·m−1, respectively. The annealing process at 700 °C considerably worsened the mechanical properties of the Ti0.94Al0.06N coating, in contrast to the Ti0.61Al0.39N coating, which manifested a high oxidation resistance at annealing temperatures of 940–950 °C.
Production of Activated Carbons from Food/Storage Waste
Authors: Wiśniewska Małgorzata , Pawlak Natalia , Sternik Dariusz , Pietrzak Robert , Nowicki Piotr
Published: February 2023

This paper deals with the adsorption of organic and inorganic pollutants on the surface of carbonaceous adsorbents prepared via the chemical activation of expired or broken food products—the solid residue of the “cola-type” drink as well as spoilt grains of white rice and buckwheat groats. The activation process was conducted in the microwave furnace with the use of two activating agents of different chemical nature—potassium carbonate and orthophosphoric acid. The activated carbons were characterized based on the results of elemental analysis, low-temperature nitrogen adsorption/desorption, Boehm titration, thermal analysis, and scanning electron microscopy. Additionally, the suitability of the materials prepared as the adsorbents of methylene blue and iodine from the aqueous solutions was estimated. The materials obtained via chemical activation with H3PO4 turned out to be much more effective in terms of both model pollutant adsorptions. The maximum sorption capacity toward iodine (1180 mg/g) was found for the white-rice-based activated carbon, whereas the most effective in the methylene blue removal (221.3 mg/g) was the sample obtained from the solid residue of the expired “cola-type” drink. For all carbonaceous materials, a better fit for the experimental adsorption data was obtained with the Langmuir isotherm model than the Freundlich one.
Thorium and Rare Earth Monoxides and Related Phases
Authors: Ushakov Sergey V. , Hong Qi-Jun , Gilbert Dustin A. , Navrotsky Alexandra , Walle Axel van de
Published: February 2023

Thorium was a part of energy infrastructure in the 19th century due to the refractory and electronic properties of its dioxide. It will be a part of future energy infrastructure as the most abundant energy reserve based on nuclear fission. This paper discusses the solid-state chemistry of the monoxides and related rocksalt phases of thorium and the rare earths, both at atmospheric and at high pressure. The existence of solid thorium monoxide was first suggested more than 100 years ago; however, it was never obtained in bulk and has been studied mostly theoretically. Monoxides of lanthanides from Eu to Ho are ferromagnetic semiconductors sought for spintronics and were studied in thin films. La to Sm metallic monoxides were synthesized in bulk at pressures below 5 GPa. Recently, ThO formation in thin films has been reported and the stability of bulk ThO at high pressure was theoretically predicted based on first principles computations at 0 K. New ab initio computations were performed accounting for temperature effects up to 1000 K using lattice dynamics in the quasi-harmonic approximation. New computational results confirm the stabilization of pure ThO above 30 GPa and suggest the possibility of high-pressure synthesis of (Th,Nd)O at 1000 K and 5 GPa.
Phase Transformations Caused by Heat Treatment and High-Pressure Torsion in TiZrHfMoCrCo Alloy
Authors: Gornakova Alena S. , Straumal Boris B. , Tyurin Alexander I. , Afonikova Natalia S. , Druzhinin Alexander V. , Davdian Gregory S. , Kilmametov Askar R.
Published: February 2023

In this work the high-entropy alloy studied contained six components, Ti/Zr/Hf/Mo/Cr/Co, and three phases, namely one phase with body-centered cubic lattice (BCC) and two Laves phases C14 and C15. A series of annealings in the temperature range from 600 to 1000 °C demonstrated not only a change in the microstructure of the TiZrHfMoCrCo alloy, but also the modification of phase composition. After annealing at 1000 °C the BCC phase almost fully disappeared. The annealing at 600 and 800 °C leads to the formation of new Laves phases. After high-pressure torsion (HPT) of the as-cast TiZrHfMoCrCo alloy, the grains become very small, the BCC phase prevails, and C14 Laves phase completely disappears. This state is similar to the state after annealing at high effective temperature Teff. The additional annealing at 1000 °C after HPT returns the phase composition back to the state similar to that of the as-cast alloy after annealing at 1000 °C. At 1000 °C the BCC phase completely wets the C15/C15 grain boundaries (GBs). At 600 and 800 °C the GB wetting is incomplete. The big spread of nanohardness and Young’s modulus for the BCC phase and (C15 + C14) Laves phases is observed.
In Vitro Investigation of Material Combinations for Meso- and Suprastructures in a Biomimetic Approach to Restore One-Piece Zirconia Implants
Authors: Nueesch Reto , Karlin Sabrina , Fischer Jens , Rohr Nadja
Published: February 2023

The aim of this study was to find a suitable material combination to avoid cement excess in the marginal region of one-piece zirconia implant-supported restorations by means of a hybrid crown consisting of a meso- and a suprastructure. One-piece zirconia implants (n = 120) were embedded in epoxy resin. Microfilled resin composite mesostructures (n = 60), designed as caps, were bonded on the implant abutment with a primer only. A molar crown was constructed and cemented with a resin cement on top of the mesostructure as a suprastructure out of feldspar ceramic (n = 12), lithium-disilicate (n = 24), or zirconia (n = 24). Fracture load (n = 6) and retention force (n = 6) were measured immediately after storage in distilled water at 37 °C for 24 h, as well as after an additional exposure to artificial aging in a chewing simulator and simultaneous thermal cycling. For the measurement of the fracture load, monolithic crowns made of the employed restorative materials and identical in shape to the hybrid crowns served as controls (n = 6 each). Fracture load values for feldspar ceramic and lithium-disilicate hybrid crowns were slightly higher than those for the respective monolithic crowns at baseline and after aging, which was statistically significant only for feldspar crowns after aging. In contrast, fracture load values for zirconia monolithic crowns were higher than those for zirconia hybrid crowns, which was only statistically significant after aging. Artificial aging reduced the fracture load of feldspar and lithium-disilicate crowns both for hybrid and monolithic crowns. The effect was only statistically significant for lithium disilicate hybrid crowns. The fracture load for hybrid and monolithic zirconia crowns was increased by artificial aging without reaching statistical significance. The retention force of lithium-disilicate and zirconia hybrid crowns was not affected by artificial aging. Taking into account retention force and fracture load, lithium-disilicate hybrid crowns showed promising results.
Contribution of Tin to the Strain Hardening of Self-Lubricating Sintered Al-30Sn Alloy and Its Wear Resistance under Dry Friction
Authors: Rusin Nikolay M. , Skorentsev Alexander L. , Dmitriev Andrey I.
Published: February 2023

Aluminum alloys, which have been widely used in various manufacturing industries as an upper layer of bearing inserts, are alloyed with Sn to decrease the intensity of adhesive wear. A relationship between the mechanical properties, wear resistance, and structure of sintered Al-30Sn alloy containing a large amount of the soft phase was studied in this work. The above-mentioned characteristics were determined by testing the investigated material under compression and wear under dry friction in the pin-on-disk geometry at a sliding speed of 0.6 m/s and pressures of 1–5 MPa. The studied alloy was prepared by sintering of compacts consisting of a mixture of commercial powders in a vacuum furnace at a temperature of 600 °C for an hour. Then, the sintered Al-30Sn samples were subjected to processing by equal channel angular pressing (ECAP) with routes A and C. It has been established that the hardening value of the alloy subjected to ECAP virtually does not depend on the Sn content, but it depends on the number of passes and the processing route. The maximum increase in the strength of the alloy was found after the first and second passes. At the fixed Sn content, its effect on the wear resistance of the alloy does not depend on the strain hardening value of the aluminum matrix.
Polycrystalline WO3−x Thin Films Obtained by Reactive DC Sputtering at Room Temperature
Authors: Guillén Cecilia
Published: February 2023

Tungsten oxide thin films have applications in various energy-related devices owing to their versatile semiconductor properties, which depend on the oxygen content and crystalline state. The concentration of electrons increases with intrinsic defects such as oxygen vacancies, which create new absorption bands that give rise to colored films. Disorders in the crystal structure produce additional changes in the electrical and optical characteristics. Here, WO3−x thin films are prepared on unheated glass substrates by reactive DC sputtering from a pure metal target, using the discharge power and the oxygen-to-argon pressure ratio as control parameters. A transition from amorphous to polycrystalline state is obtained by increasing the sputtering power and adjusting the oxygen content. The surface roughness is higher and the bandgap energy is lower for polycrystalline layers than for amorphous ones. Moreover, the electrical conductivity and sub-bandgap absorption increase as the oxygen content decreases.
Procedure to Obtain Cu2O Isolate Films, Structural, Electrical, and Morphological Characterization, and Its Use as an Electrical Isolator to Build a New Tube Furnace
Authors: Correa Hernando , Pineda Sánchez Ricardo , Peña Lara Diego
Published: February 2023

Copper oxide is a widely studied compound in wastewater decontamination, hydrogen production, solar cell production, and sensor fabrication. In recent years, many architectures and structures with the potential for developing clean technologies have been synthesized. A procedure by thermal oxidation to grow electrical insolate Cu2O films on copper surfaces in an air atmosphere was developed. The results of the morphological and structural characterization of the copper oxide layers evidence the presence of Cu2O polycrystalline films. The films have polyhedral architectures of approximately 1.4 μm thickness and are electrically insulating. A novel copper resistive furnace was built using this copper oxide film which was used as an electrical insulator between the electrical resistance of the heater and the surface of the copper thermal block. The application improves the efficiency of the resistive furnace in terms of the temperature reached and the thermal coupling response time relative to the performance of conventional furnaces using ceramic insulation. Over the entire operating temperature range explored for the same power supply, the copper oxide-coated furnace achieved higher temperatures and faster response times than the traditionally coated furnace.
The Influence of the ITO Layers’ Thicknesses on Their Chosen Physical Surface Parameters
Authors: Musztyfaga-Staszuk Małgorzata , Gawlińska-Nęcek Katarzyna , Socha Robert , Panek Piotr
Published: February 2023

The paper presents the results concerning the influence of the thickness of the ITO and In2O3 layers deposited by the magnetron sputtering method on the physical parameters characterising their surface properties. The characterisation parameters were obtained by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and Kelvin probe. The increase in the layers’ thickness related to the time of their fabrication causes an increase in the surface roughness and the value of the work function, followed by a decrease in the concentration of elements and compounds in the near-surface area.
3D-Printed Soft Membrane for Periodontal Guided Tissue Regeneration
Authors: Vahdatinia Farshid , Hooshyarfard Amirarsalan , Jamshidi Shokoofeh , Shojaei Setareh , Patel Kishan , Moeinifard Erfan , Haddadi Rasool , Farhadian Maryam , Gholami Leila , Tayebi Lobat
Published: February 2023

Objectives: The current study aimed to perform an in vivo examination using a critical-size periodontal canine model to investigate the capability of a 3D-printed soft membrane for guided tissue regeneration (GTR). This membrane is made of a specific composition of gelatin, elastin, and sodium hyaluronate that was fine-tuned and fully characterized in vitro in our previous study. The value of this composition is its potential to be employed as a suitable replacement for collagen, which is the main component of conventional GTR membranes, to overcome the cost issue with collagen. Methods: Critical-size dehiscence defects were surgically created on the buccal surface of the roots of canine bilateral mandibular teeth. GTR treatment was performed with the 3D-printed membrane and two commercially available collagen membranes (Botiss Jason® and Smartbrane-Regedent membranes) and a group without any membrane placement was considered as the control group. The defects were submerged with tension-free closure of the gingival flaps. Histologic and histometric analyses were employed to assess the periodontal healing over an 8-week experimental period. Results: Histometric evaluations confirmed higher levels of new bone formation in the 3D-printed membrane group. Moreover, in all defects treated with the membranes, the formation of periodontal tissues, bone, periodontal ligaments, and cementum was observed after 8 weeks, while in the control group, only connective tissue was found in the defect sites. There was no clinical sign of inflammation or recession of gingiva in any of the groups. Significance: The 3D-printed gelatin/elastin/sodium hyaluronate membrane can be safe and effective for use in GTR for periodontal tissue regeneration therapies, with better or comparable results to the commercial collagen membranes.
Laser Treatment of Surfaces for Pool Boiling Heat Transfer Enhancement
Authors: Orman Łukasz J. , Radek Norbert , Pietraszek Jacek , Wojtkowiak Janusz , Szczepaniak Marcin
Published: February 2023

The laser treatment of surfaces enables the alteration of their morphology and makes them suitable for various applications. This paper discusses the use of a laser beam to develop surface features that enhance pool boiling heat transfer. Two types of structures (in the ‘macro’ and ‘micro’ scale) were created on the samples: microfins (grooves) and surface roughness. The impact of the pulse duration and scanning velocity on the height of the microfins and surface roughness at the bottom of the grooves was analyzed with a high precision optical profilometer and microscope. The results indicated that the highest microfins and surface roughness were obtained with a pulse duration of 250 ns and scanning velocity of 200 mm/s. In addition, the influence of the ‘macro’ and ‘micro’ scale modifications on the boiling heat transfer of distilled water and ethyl alcohol was studied on horizontal samples heated with an electric heater. The largest enhancement was obtained for the highest microfins and roughest surfaces, especially at small superheats. Heat flux dissipated from the samples containing microfins of 0.4 mm height was, maximally, over three times (for water) and two times (for ethanol) higher than for the samples with smaller microfins (0.2 mm high). Thus, a modification of a selected model of boiling heat transfer was developed so that it would be applicable to laser-processed surfaces. The correlation proved to be quite successful, with almost all experimental data falling within the ±100% agreement bands.
Soft Actor–Critic-Driven Adaptive Focusing under Obstacles
Authors: Lu Huan , Zhu Rongrong , Wang Chi , Hua Tianze , Zhang Siqi , Chen Tianhang
Published: February 2023

Electromagnetic (EM) waves that bypass obstacles to achieve focus at arbitrary positions are of immense significance to communication and radar technologies. Small-sized and low-cost metasurfaces enable the accomplishment of this function. However, the magnitude-phase characteristics are challenging to analyze when there are obstacles between the metasurface and the EM wave. In this study, we creatively combined the deep reinforcement learning algorithm soft actor–critic (SAC) with a reconfigurable metasurface to construct an SAC-driven metasurface architecture that realizes focusing at any position under obstacles using real-time simulation data. The agent learns the optimal policy to achieve focus while interacting with a complex environment, and the framework proves to be effective even in complex scenes with multiple objects. Driven by real-time reinforcement learning, the knowledge learned from one environment can be flexibly transferred to another environment to maximize information utilization and save considerable iteration time. In the context of future 6G communications development, the proposed method may significantly reduce the path loss of users in an occluded state, thereby solving the open challenge of poor signal penetration. Our study may also inspire the implementation of other intelligent devices.
The Use of Toothpastes Containing Different Formulations of Fluoride and Bioglass on Bleached Enamel
Authors: Ergucu Zeynep , Yoruk Inci , Erdoğan Ayşegül , Boyacıoğlu Hayal , Hill Robert , Baysan Aylin
Published: February 2023

Objectives: To investigate the application of toothpaste either containing calcium sodium phospho-silicate bioglass (NovaMin) or calcium fluorosilicate bioglass (BioMinF) on the surface mineral composition and morphology of enamel after bleaching procedure. Methods: Thirty extracted noncarious human teeth were allocated into five groups (n = 6). Group 1: Bleaching using 40% hydrogen peroxide (HP) and fluoridated toothpaste containing bioactive glass (1450 ppm fluoride). Group 2: Bleaching using 40%HP and toothpaste containing calcium fluorosilicate bioglass (540 ppm fluoride). Group 3: Bleaching using 40%HP and fluoridated toothpaste (1450 ppm fluoride). Group 4: Bleaching alone using 40%HP. Group 5: Negative control with distilled water alone. The surface morphology was evaluated using Scanning Electron Microscope (SEM) and Scanning Probe Microscope (SPM). The concentration of elements as atomic percentages were determined by X-ray Photoelectron Spectroscopy (XPS) and Energy-Dispersive X-ray Spectroscopy (EDS). Results: This laboratory-based study reported that SPM and SEM detected minor changes on the surfaces of all toothpaste-treated enamel samples (Groups 1–3) after 45 days. Bioactive glass deposits were observed on enamel surfaces in Groups 1 and 2, whilst the bleaching-alone samples (Group 4) had rough enamel surfaces. XPS reported that toothpaste containing calcium fluorosilicate bioglass (Group 2) had a high atomic% of calcium and phosphate, whilst silicon values were high in the toothpaste containing bioactive glass and 1450 ppm fluoride (Group 1) after bleaching procedure when compared to other groups (p < 0.05). In addition, EDS detected the highest %F in Groups 1, 2 and 5. Conclusions: Within the limitations of this laboratory-based study, there was no significant decrease in the Ca%, P% values and surface properties of enamel after the bleaching procedure following the use of different formulations of toothpastes for a period of 45 days. However, the Ca% and P% values were significantly high for the toothpaste containing calcium fluorosilicate bioglass (BioMinF) on the bleached enamel. Clinical relevance: The bleaching process can provide optimum aesthetic outcomes, but the effect of peroxides on hard tissues is still in question. Toothpastes containing different formulations of fluoride and bioactive glass might have the potential to prevent mineral loss on bleached enamel. However, further laboratory-based studies and controlled double-blind randomised clinical trials are required to interpret the effects of toothpastes with different fluoride and bioactive glass formulations on enamel surfaces following bleaching procedures.
Market Demand Optimization Model Based on Information Perception Control
Authors: Yuan Guanghui , Liu Zhiqiang , Wang Yaqiong , Pu Dongping
Published: February 2023

The development of Internet technology and the rise of social networks have expanded the means of product information dissemination. Nowadays, consumers can obtain not only product quality information through real life contacts, but can also obtain product cognitive information through virtual networks, which constitute consumers’ information perception together. However, information in the market can be controlled, and companies can change the perceptions of their consumer base towards their products by enhancing the dissemination of information on the Internet, thus achieving higher corporate revenue. This article aims to study the evolution process of market demand under the control of consumers’ information perception, and a two-layer network model consisting of a cognitive information layer and a quality information layer were constructed. In order to improve product information dissemination efficiency, the opinion leaders who are more active in responding to mentions of the product across social networks are selected, and these opinion leaders are influenced in a stepwise manner using the maximum influence model, thus investigating the relationship between resources and corporate revenue. Using scale-free networks for simulation analysis, there are three main conclusions. First, the cognitive information and quality information of the product could affect market demand. Second, product demand and company profits would increase significantly if key individuals were added to the cognitive information layer. Third, the incremental marginal effect of key individuals decreases as their number increases.
Integration of Pre-Treatment with UF/RO Membrane Process for Waste Water Recovery and Reuse in Agro-Based Pulp and Paper Industry
Authors: Dagar Sumit , Singh Santosh , Gupta Manoj
Published: February 2023

This recent study aims to evaluate the efficacy of membrane filtration on recovery of water resource from agro-waste such as bagasse, crop-based pulp and paper mill waste. A mini pilot scale membrane system having a combination of pre-treatment filter unit (pre-filter, sediment filter and pre-carbon filter), ultra-filtration and reverse osmosis with spiral wound configuration were employed to evaluate the water reuse efficacy of effluent coming from the secondary clarifier of the conventional treatment plant of the mill. The operational conditions were optimized using Taguchi method at pH 8, temperature 32 °C, and pressure 2 bar and a flow rate of 60 l/hr. The qualities of the effluent from the secondary clarifier, and the permeate from both the combination, viz. Combination 1 (pre-treatment + ultra-filtration) and Combination 2 (pre-treatment + ultra-filtration+ reverse osmosis) were analyzed and the percentage reduction in pH, TDS, TSS, BOD, COD, Color, Lignin, Potassium and Sodium were calculated. The elimination of TDS, COD and BOD with Combination 1 was not promising (<22%). However, the installation of a RO membrane greatly reduced (>88%) the contaminants in both paper mill effluents. The obtained qualities of water from all the combinations were compared with the tolerance standard for reuse as process water. The quality of effluent from the secondary clarifier did not agree with any class of water quality. The permeate from the combination of pre-treatment and UF sufficiently reduced the TSS to reach the requirement. However, the combination of (pre-treatment + UF + RO) adequately complied with the quality standard required for reuse in the making of all grades of paper.
Quercetin Induces Apoptosis in HepG2 Cells via Directly Interacting with YY1 to Disrupt YY1-p53 Interaction
Authors: Guan Hui , Zhang Wenyuan , Liu Hui , Jiang Yang , Li Feng , Wu Maoyu , Waterhouse Geoffrey I. N. , Sun-Waterhouse Dongxiao , Li Dapeng
Published: February 2023

Quercetin is a flavonol found in edible plants and possesses a significant anticancer activity. This study explored the mechanism by which quercetin prevented liver cancer via inducing apoptosis in HepG2 cells. Quercetin induced cell proliferation and apoptosis through inhibiting YY1 and facilitating p53 expression and subsequently increasing the Bax/Bcl-2 ratio. The results revealed that YY1 knockdown promoted apoptosis, whilst YY1 overexpression suppressed apoptosis via direct physical interaction between YY1 and p53 to regulate the p53 signaling pathway. Molecular docking using native and mutant YY1 proteins showed that quercetin could interact directly with YY1, and the binding of quercetin to YY1 significantly decreased the docking energy of YY1 with p53 protein. The interactions between quercetin and YY1 protein included direct binding and non-bonded indirect interactions, as confirmed by cellular thermal shift assay, UV-Vis absorption spectroscopy, fluorescence spectroscopy and circular dichroism spectroscopy. It was likely that quercetin directly bound to YY1 protein to compete with p53 for the binding sites of YY1 to disrupt the YY1-p53 interaction, thereby promoting p53 activation. This study provides insights into the mechanism underlying quercetin’s anticancer action and supports the development of quercetin as an anticancer therapeutic agent.
Metabolomic Strategies to Improve Chemical Information from OSMAC Studies of Endophytic Fungi
Authors: da Silva Fernanda Motta Ribeiro , Paggi Gecele Matos , Brust Flávia Roberta , Macedo Alexandre José , Silva Denise Brentan
Published: February 2023

Metabolomics strategies are important tools to get holistic chemical information from a system, but they are scarcely applied to endophytic fungi to understand their chemical profiles of biosynthesized metabolites. Here Penicillium sp. was cultured using One Strain Many Compounds (OSMAC) conditions as a model system to demonstrate how this strategy can help in understanding metabolic profiles and determining bioactive metabolites with the application of metabolomics and statistical analyses, as well as molecular networking. Penicillium sp. was fermented in different culture media and the crude extracts from mycelial biomass (CEm) and broth (CEb) were obtained, evaluated against bacterial strains (Staphylococcus aureus and Pseudomonas aeruginosa), and the metabolomic profiles by LC-DAD-MS were obtained and chemometrics statistical analyses were applied. The CEm and CEb extracts presented different chemical profiles and antibacterial activities; the highest activities observed were against S. aureus from CEm (MIC = 16, 64, and 128 µg/mL). The antibacterial properties from the extracts were impacted for culture media from which the strain was fermented. From the Volcano plot analysis, it was possible to determine statistically the most relevant features for the antibacterial activity, which were also confirmed from biplots of PCA as strong features for the bioactive extracts. These compounds included 75 (13-oxoverruculogen isomer), 78 (austalide P acid), 87 (austalide L or W), 88 (helvamide), 92 (viridicatumtoxin A), 96 (austalide P), 101 (dihydroaustalide K), 106 (austalide k), 110 (spirohexaline), and 112 (pre-viridicatumtoxin). Thus, these features included diketopiperazines, meroterpenoids, and polyketides, such as indole alkaloids, austalides, and viridicatumtoxin A, a rare tetracycline.
Nanoantioxidant Materials: Nanoengineering Inspired by Nature
Authors: Fragou Fotini , Theofanous Annita , Deligiannakis Yiannis , Louloudi Maria
Published: February 2023

Oxidants are very active compounds that can cause damage to biological systems under specific environmental conditions. One effective way to counterbalance these adverse effects is the use of anti-oxidants. At low concentrations, an antioxidant is defined as a compound that can delay, control, or prevent an oxidative process. Antioxidants exist in plants, soil, and minerals; therefore, nature is a rich source of natural antioxidants, such as tocopherols and polyphenols. In nature, antioxidants perform in tandem with their bio-environment, which may tune their activity and protect them from degradation. In vitro use of antioxidants, i.e., out of their biomatrix, may encounter several drawbacks, such as auto-oxidation and polymerization. Artificial nanoantioxidants can be developed via surface modification of a nanoparticle with an antioxidant that can be either natural or synthetic, directly mimicking a natural antioxidant system. In this direction, state-of-the-art nanotechnology has been extensively incorporated to overcome inherent drawbacks encountered in vitro use of antioxidants, i.e., out of their biomatrix, and facilitate the production and use of antioxidants on a larger scale. Biomimetic nanoengineering has been adopted to optimize bio-medical antioxidant systems to improve stability, control release, enhance targeted administration, and overcome toxicity and biocompatibility issues. Focusing on biotechnological sciences, this review highlights the importance of nanoengineering in developing effective antioxidant structures and comparing the effectiveness of different nanoengineering methods. Additionally, this study gathers and clarifies the different antioxidant mechanisms reported in the literature and provides a clear picture of the existing evaluation methods, which can provide vital insights into bio-medical applications.