bluuebunny/crossref_metadata_2025 huggingface dataset:
Connexin43 in Post-Surgical Peritoneal Adhesion Formation
Authors: Chua Jia Wang , Thangaveloo Moogaambikai , Lim Debbie Xiu En , Madden Leigh E. , Phillips Anthony R. J. , Becker David L.
Published: October 2022

Objective: Post-surgical peritoneal adhesions are a serious problem for the quality of life and fertility. Yet there are no effective ways of preventing their occurrence. The gap junction protein Cx43 is known to be involved in fibrosis in several different organs and disease conditions often associated with inflammation. Here we examined the Cx43 dynamic expression in an ischemic button model of surgical adhesions. Methods: Using the mouse ischemic button model, Cx43 antisense was delivered in Pluronic gel to attenuate Cx43 expression. The severity of button formation and immunofluorescence analysis of Cx43 and TGF-β1 were performed. The concentration of tissue plasminogen activator via ELISA was also performed. Results: As early as 6 h after button formation, the Cx43 levels were elevated in and around the button and some weak adhesions were formed. By 24 h Cx43 levels had increased further and adhesions were more defined. At 7 days the adhesions were much more robust, opaque, and vascularized, requiring blunt or sharp dissection to break them. Cx43 antisense attenuated its upregulation and, reduced the number and severity of adhesions that formed. Conclusion: Targeting Cx43 after surgical procedures may be a potential therapeutic strategy for preventing adhesion formation or at least reducing their severity.
Associations between Deformation of the Thoracolumbar Fascia and Activation of the Erector Spinae and Multifidus Muscle in Patients with Acute Low Back Pain and Healthy Controls: A Matched Pair Case-Control Study
Authors: Brandl Andreas , Egner Christoph , Reer Rüdiger , Schmidt Tobias , Schleip Robert
Published: October 2022

Background: The thoracolumbar fascia (TLF) is thought to play a role in the development of LBP, but it is not yet clear which factor of TLF changes is a cause and which is an effect. Therefore, some studies used the cross-correlation function (CCR) to reveal time-dependent relationships between biomechanical and neuromotor factors. Methods: Ten patients with acute low back pain (aLBP) were matched to healthy controls. Simultaneous recording of surface electromyography (sEMG) of the erector spinae and multifidus muscle (ESM) and dynamic ultrasound (US) images of TLF deformation were performed during trunk extension. CCR functions and Granger causality (GC) were used to describe the relationship between the two measures. Results: CCR time lags were significant higher in the aLBP group (p = 0.04). GC showed a direct effect of TLF deformation on ESM activation only in the aLBP group (p < 0.03). Conclusions: The results suggest that in aLBP, ESM activity is significantly affected by TLF, whereas this relationship is completely random in healthy subjects studied with CCR and GC comparisons of dynamic US imaging and sEMG data signals. Fascia-related disturbances in neuromotor control, particularly due to altered muscle spindle functions, are suspected as a possible mechanism behind this.
Autologous Matrix-Induced Chondrogenesis (AMIC) for Osteochondral Defects of the Talus: A Systematic Review
Authors: Migliorini Filippo , Maffulli Nicola , Bell Andreas , Hildebrand Frank , Weber Christian , Lichte Philipp
Published: October 2022

Autologous matrix-induced chondrogenesis (AMIC) has been advocated for the management of talar osteochondral lesions (OCLs). This systematic review, which was conducted according to the PRISMA 2020 guidelines, investigated the clinical and imaging efficacy and safety of the AMIC technique in the management of OCLs of the talus. Only studies investigating AMIC for talar chondral defects that were published in peer-reviewed journals were considered. In September 2022, the following databases were accessed: PubMed, Web of Science, Google Scholar, and Embase. Data on the visual analogue scale (VAS), American Orthopaedic Foot and Ankle Score (AOFAS), Tegner activity scale, and Foot Function Index (FFI) were retrieved. To evaluate the morphological MRI findings, data obtained from the magnetic resonance observation of cartilage repair tissue (MOCART) scores were evaluated. Data on hypertrophy, failures, and revision surgeries were also collected. Data from 778 patients (39% women, 61% men) were collected. The mean length of the follow-up was 37.4 ± 16.1 months. The mean age of the patients was 36.4 ± 5.1 years, and the mean BMI was 26.1 ± 1.6 kg/m2. The mean defect size was 2.1 ± 1.9 cm2. Following the AMIC technique, patients demonstrated an improved VAS (p < 0.001), AOFAS (p < 0.001), and FFI (p = 0.02) score. The MOCART score also improved from the baseline (p = 0.03). No difference was observed in the Tegner score (p = 0.08). No graft delamination and hypertrophy were reported in 353 patients. 7.8% (44 of 564) of patients required revision surgeries, and 6.2% (32 of 515) of patients were considered failures. The AMIC technique could be effective in improving symptoms and the function of chondral defects of the talus.
Cerebello-Thalamo-Cortical MR Spectroscopy in Patients with Essential Tremor Undergoing MRgFUS Thalamotomy: A Pilot Study
Authors: Bruno Federico , Tommasino Emanuele , Catalucci Alessia , Piccin Veronica , Innocenzi Antonio , Carugno Maria Ester , Colarieti Filippo , Pertici Leonardo , Di Gioia Antonio , D’Alessandro Claudia , Fagotti Cristina , Sucapane Patrizia , Pistoia Francesca , Palumbo Pierpaolo , Arrigoni Francesco , Di Cesare Ernesto , Marini Carmine , Barile Antonio , Splendiani Alessandra , Masciocchi Carlo
Published: October 2022

Previous literature studies explored the association between brain neurometabolic changes detected by MR spectroscopy and symptoms in patients with tremor, as well as the outcome after deep brain stimulation (DBS) treatment. The purpose of our study was to evaluate the possible changes in cerebello-thalamo-cortical neurometabolic findings using MR spectroscopy in patients submitted to MRgFUS thalamotomy. For this pilot study, we enrolled 10 ET patients eligible for MRgFUS thalamotomy. All patients were preoperatively submitted to 3T MR spectroscopy. Single-voxel MRS measurements were performed at the level of the thalamus contralateral to the treated side and the ipsilateral cerebellar dentate nucleus. Multivoxel acquisition was used for MRS at the level of the contralateral motor cortex. At the 6-month follow-up after treatment, we found a statistically significant increase in the Cho/Cr ratio at the level of the thalamus, a significant increase of the NAA/Cr ratio at the level of the dentate nucleus and a significant decrease of the NAA/Cho ratio at the level of the motor cortex. We found a significant positive correlation between cortical NAA/Cr and clinical improvement (i.e., tremor reduction) after treatment. A significant negative correlation was found between clinical improvement and thalamic and cerebellar NAA/Cr. Confirming some previous literature observations, our preliminary results revealed neurometabolic changes and suggest a possible prognostic role of the MRS assessment in patients with ET treated by MRgFUS.
Multi-Omics Analysis Reveals Clinical Value and Possible Mechanisms of ATAD1 Down-Regulation in Human Prostate Adenocarcinoma
Authors: Chen Chun-Chi , Chu Pei-Yi , Lin Hung-Yu
Published: October 2022

Prostate adenocarcinoma (PRAD) is the most common histological subtype of prostate cancer. Post-treatment biochemical recurrence is a challenging issue. ATAD1 (ATPase Family AAA Domain Containing 1) plays a vital role in mitochondrial proteostasis and apoptosis activity, while its clinical value in PRAD and its impact on the tumor microenvironment (TME) remain unanswered. In this study, we aimed to investigate the clinical value and possible mechanisms of ATAD1 in PRAD via multi-omics analysis. Using cBioPortal, we confirmed that ATAD1 alteration was associated with gene expression and unfavorable DFS. Deep deletion predominantly occurred in PRAD. By integrating DriverDBv3 and GEPIA2, we noted ATAD1 downregulation in PRAD tissues compared to normal tissues, associated with unfavorable DFS in PRAD patients. DNA repair genes ATM, PARP1and BRCA2 had positive associations with ATAD1 expression. We found that the generalization value of ATAD1 could be applied to other cancers such as KIRC and UCEC. In addition, LinkedOmics identified that the functional involvement of ATAD1 participates in mitochondrial structure and cell cycle progression. Using TIMER analysis, we demonstrated that ATAD1 downregulation correlated with an immunosuppressive TME. Furthermore, we accessed a GSE55062 dataset on UALCAN and discovered the involvement of ERG-mediated transcriptional repression on ATAD1 downregulation. Cross-association screening of shATAD1 efficacy vs. altered mRNAs identified 190 perturbed mRNAs. Then, functional enrichment analysis using the Metascape omics tool recognized that shATAD1-perturbed mRNAs are primarily in charge of the activation of Wnt/β-catenin pathway and lipid metabolic processes. In conclusion, multi-omics results reveal that ATAD1 downregulation is a clinical biomarker for pathological diagnosis and prognosis for patients with PRAD. Reduced ATAD1 may be involved in the enhanced activity of mitochondria and cell cycle, as well as possibly shaping an immunosuppressive TME. ERG serves as an upstream transcriptional repressor of ATAD1. Downstream mechanisms of ATAD1 are involved in Wnt/β-catenin pathway and lipid metabolic processes.
The Significance of Machine Learning in the Manufacturing Sector: An ISM Approach
Authors: Lakra Alisha , Gupta Shubhkirti , Ranjan Ravi , Tripathy Sushanta , Singhal Deepak
Published: October 2022

Background: Our day-to-day commodities truly depend on the industrial sector, which is expanding at a rapid rate along with the growing population. The production of goods needs to be accurate and rapid. Thus, for the present research, we have incorporated machine-learning (ML) technology in the manufacturing sector (MS). Methods: Through an inclusive study, we identify 11 factors within the research background that could be seen as holding significance for machine learning in the manufacturing sector. An interpretive structural modeling (ISM) method is used, and inputs from experts are applied to establish the relationships. Results: The findings from the ISM model show the ‘order fulfillment factor as the long-term focus and the ‘market demand’ factor as the short-term focus. The results indicate the critical factors that impact the development of machine learning in the manufacturing sector. Conclusions: Our research contributes to the manufacturing sector which aims to incorporate machine learning. Using the ISM model, industries can directly point out their oddities and improve on them for better performance.
Influence Analysis of Lubricant Recesses on the Working Capacity of the Bridge Span Spherical Bearing
Authors: Nosov Yuriy O. , Kamenskikh Anna A.
Published: October 2022

The load on transport and logistics systems is increasing every year. This is due to car park growth around the world. Thus, increasing bridge structure durability is an urgent task for bridge-building companies. This study analyses the contact deformation of spherical bearing elements through an anti-friction polymer layer with different geometrical configurations of recesses for the lubricant, i.e., annular grooves and spherical holes. The material of the anti-friction layer (a modified polytetrafluoroethylene (PTFE)) is modelled within the framework of the deformation theory of plasticity. The procedure of automating the numerical model construction depends on the input parameters, including the thickness of the layer, the basic geometrical parameters of the recesses for the lubricant, and the distance between the rows of recesses, etc. The influence of the arrangement of filling sliding anti-friction layers on recesses for lubricants in the form of spherical holes on the contact deformation behaviour of bridge bearings has been considered. The reduction of lubricant volume in the sliding anti-friction layer with the geometry of recesses in the form of spherical holes ranges from 26 to 48.4%, depending on the filling scheme, has been found. In this case, structures with lubrication recesses in the form of spherical holes have several advantages, including a more uniform distribution of contact parameters in the interface areas of the steel plates with the anti-friction layer, reduction of the maximum level of the plastic deformation intensity, displacements along the normal relative to the free end of the sliding layer, and the settlement of the bearing.
Occurrence of Grease Lubricated Impact-Sliding Composite Wear
Authors: Lv Zhendong , Han Yiming , Zhang Rui , Wang Jing
Published: October 2022

In industrial chain drives, the sleeve slides on the pin and impact loading occurs due to the polygon effect, while the collision between the ball and cage usually produces an impact-sliding motion in the rolling element bearings. Aiming at addressing the occurrence of surface damage caused by the impact-sliding motion, a ball–disk test rig employing optical interference technology was designed and built to realize load variation. Two kinds of commercial grease types, Klüber Centoplex 3 and Centoplex 2EP, were used in the experiments when the glass disk slides at a constant speed while the steel ball collides into them. The sliding and impact motions were controlled by PLC programming. After the experiments, the mid-section grease film distributions were measured using DIIM software. The results show that surface damage can rapidly occur even in the first working cycle, and that the phenomenon is affected by the sliding speed, maximum load, and grease consistency. When the sliding speed is low, multiple contacts of asperity peaks occur in the interior contact region and develop into adhesive wear. When the sliding speed increases, surface wear starts to occur at the side-lobe position of the elastohydrodynamic lubrication (EHL) horseshoe shape and extends with time accompanied by obvious surface scratches. The wear mechanism investigated provides valuable visible information for the further exploration of impact-sliding composite wear. It is suggested that great attention should be paid to impact-sliding wear occurring with grease lubrication since such working conditions are very common in industrial applications.
Tribological and Mechanical Properties of the Nanostructured Superlattice Coatings with Respect to Surface Texture
Authors: Jansons Ernests , Lungevics Janis , Kanders Uldis , Leitans Armands , Civcisa Guna , Linins Oskars , Kundzins Karlis , Boiko Irina
Published: October 2022

Ceramic Nanostructured Superlattice Coatings (NSC) have broad applicability to improve the parts’ and assemblies’ tribological and mechanical properties for the needs of the automotive and aerospace industries. Improving the material properties using nanocoatings for such a widely used material as, for example, bearing steel 100Cr6 makes it possible to improve the service life of machine parts. In this paper, the correlation dependence between tribological and mechanical properties of the NSC and its surface texture are considered to determine how much surface texture will affect the tribological performance of the coated workpieces, as well as the measuring and evaluation procedure of the nanocoatings, are presented. Three different NSC described by a general empirical formula {TiMe1Me2-CN/TiAlSi-N}n and based on the modified carbonitride/nitride non-stoichiometric chemical composition were created, and their tribological and mechanical properties measured and analyzed in the context with surface texture. NSC deposited by the advanced PVD (Physical vapor deposition) technique demonstrated significantly higher wear resistance (up to 28 times), reasonably lower friction coefficient (CoF) (up to 4 times), and significantly higher hardness of the coated workpieces (up to 7 times) versus substrate material. A strong correlation between the steady-state dry sliding friction, CoF, and the amplitude and functional surface texture parameters of tribo-track were observed. The first results of the initiated research regarding the correlation analysis of the tribological and mechanical properties, on the one hand, and surface texture, on the other hand, of the NSC are reported here.
Identification and Validation of Linear Friction Models Using ANOVA and Stepwise Regression
Authors: Strobl Patrick , Schermer Elias , Groetsch Daniel , Pointner-Gabriel Lukas , Voelkel Katharina , Pflaum Hermann , Stahl Karsten
Published: October 2022

For wet disk clutches, the energy input is strongly influenced by its friction behavior. However, the friction behavior cannot be simulated and therefore is mostly derived from experimental data for specific clutch systems. This paper presents a new approach for the identification and validation of linear friction models using analysis of variance (ANOVA) and stepwise regression. Therefore, we use experimental data of three different friction systems with paper- and carbon-based friction lining. The designed experiments support an efficient parameter-based analysis of the friction behavior. The obtained models can be used as an input for thermal simulations, for example, but can also support a better understanding of the main influencing factors and are applicable to various friction systems. For validation, the obtained models are applied to measured data. A good correspondence between the simulated and measured friction behavior can be shown for speeds in the investigated operating range. The presented procedure can be easily adapted, for different factors and operation modes, as well as other applications.
6-Bromo-1-hydroxyhexane-1,1-bisphosphonic Acid Monosodium Salt
Authors: Turhanen Petri A.
Published: October 2022

The synthesis of 6-bromo-1-hydroxyhexane-1,1-bisphosphonic acid monosodium salt has been described in detail and characterized by 1H, 13C, 31P NMR spectroscopy and high-resolution MS methods. Bisphosphonates are highly important compounds having a lot of medicinal and non-medicinal applications.
Acridine and Its Derivatives: Synthesis, Biological, and Anticorrosion Properties
Authors: Goni Lipiar K. M. O. , Jafar Mazumder Mohammad A. , Tripathy Divya B. , Quraishi Mumtaz A.
Published: October 2022

The phenomenon of corrosion threatens metallic components, human safety, and the economy. Despite being eco-friendly and promising as a corrosion inhibitor, acridine has not been explored to its full potential. In this review, we have discussed multiple biological activities that acridines have been found to show in a bid to prove that they are environmentally benign and much less toxic than many inhibitors. Some synthetic routes to acridines and substituted acridines have also been discussed. Thereafter, a multitude of acridines and substituted acridines as corrosion inhibitors of different metals and alloys in various corrosive media have been highlighted. A short mechanistic insight into how acridine-based compounds function as corrosion inhibitors have also been included. We believe this review will generate an impression that there is still much to learn about previously reported acridines. In the wake of recent surges to find efficient and non-toxic corrosion inhibitors, acridines and their analogs could be an appropriate answer.
The Comparison of the Effects of Nodular Cast Iron Laser Alloying with Selected Substances
Authors: Paczkowska Marta
Published: October 2022

The aim of this research was to compare the effects of laser treatment, with the same heating conditions, using four selected alloying substances (silicon, cobalt, silicon nitride and titanium), in the surface layer of nodular cast iron. The treatment was performed with a molecular laser. As the microstructure observation revealed, the greatest amount of implemented elements was diluted during the treatment in a solid solution. In all cases (except during the alloying process with cobalt), in the alloying zone, a fine and homogeneous microstructure was found. In the alloying zone, cobalt counteracted the formation of the martensitic microstructure so effectively that austenite turned into exclusively fine perlite (or bainite at most). The size of the obtained alloyed zone was different, despite the same laser heat treatment parameters. A 30% smaller depth of zone after laser alloying with silicon nitride, as compared with alloying with cobalt or silicon, was observed. The highest strengthening of the alloyed zone could be expected when silicon (hardness was approx. 980HV0.1 and the modulus of elasticity was 208 GPa) and titanium (hardness was approx. 880HV0.1 and the modulus of elasticity was 194 GPa) were used. The lowest hardness (700HV0.1) was observed for the zone alloyed with cobalt due to pearlite (or bainite) existence.
Does Multifunctional Acrylate’s Addition to Methacrylate Improve Its Flexural Properties and Bond Ability to CAD/CAM PMMA Block?
Authors: Maruo Yukinori , Yoshihara Kumiko , Irie Masao , Nagaoka Noriyuki , Matsumoto Takuya , Minagi Shogo
Published: October 2022

This study investigated the effects of a multifunctional acrylate copolymer—Trimethylolpropane Triacrylate (TMPTA) and Di-pentaerythritol Polyacrylate (A-DPH)—on the mechanical properties of chemically polymerized acrylic resin and its bond strength to a CAD/CAM polymethyl methacrylate (PMMA) disk. The methyl methacrylate (MMA) samples were doped with one of the following comonomers: TMPTA, A-DPH, or Trimethylolpropane Trimethacrylate (TMPTMA). The doping ratio ranged from 10 wt% to 50 wt% in 10 wt% increments. The flexural strength (FS) and modulus (FM) of PMMA with and without comonomer doping, as well as the shear bond strength (SBS) between the comonomer-doped PMMA and CAD/CAM PMMA disk, were evaluated. The highest FS (93.2 ± 4.2 MPa) was obtained when doped with 20 wt% of TMPTA. For TMPTMA, the FS decreased with the increase in the doping ratio. For SBS, TMPTA showed almost constant values (ranging from 7.0 to 8.2 MPa) regardless of the doping amount, and A-DPH peaked at 10 wt% doping (8.7 ± 2.2 MPa). TMPTMA showed two peaks at 10 wt% (7.2 ± 2.6 MPa) and 40 wt% (6.5 ± 2.3 MPa). Regarding the failure mode, TMPTMA showed mostly adhesive failure between the CAD/CAM PMMA disk and acrylic resin while TMPTA and A-DPH showed an increased rate of cohesive or mixed failures. Acrylate’s addition as a comonomer to PMMA provided improved mechanical properties and bond strength to the CAD/CAM PMMA disk.
Evaluation of a Laboratory-Scale Gas-Atomized AlSi10Mg Powder and a Commercial-Grade Counterpart for Laser Powder Bed Fusion Processing
Authors: Marinucci Fabrizio , Aversa Alberta , Manfredi Diego , Lombardi Mariangela , Fino Paolo
Published: October 2022

Laser powder bed fusion (LPBF) is an additive manufacturing technology that implies using metal powder as a raw material. The powders suitable for this kind of technology must respect some specific characteristics. Controlled gas atomization and post-processing operations can strongly affect the final properties of the powders, and, as a consequence, the characteristics of the bulk components. In fact, a complete characterization of the powders is mandatory to fully determine their properties. Beyond the most used tests, such as the volume particle size distribution (PSD) and flowability, the PSD number, the Hausner ratio and the oxidation level can give additional information otherwise not detectable. The present work concerns the complete characterization of two AlSi10Mg powders: a commercial-grade gas atomized powder and a laboratory-scale gas atomized counterpart. The laboratory-scale gas atomization allows to better manage the amount of the fine particles and the oxidation level. As a consequence, a higher particle packing can be reached with an increase in the final density and tensile strength of the LPBF bulk samples.
The Effect of Extrusion and Heat Treatment on the Microstructure and Tensile Properties of 2024 Aluminum Alloy
Authors: Li Qilun , Zhang Xiaobo , Wang Lei , Qiao Jisen
Published: October 2022

Hot extrusion forming is one of the best cost-effective processing methods to obtain high-strength aluminum alloys. In order to obtain high performance 2024 aluminum alloy for the aero and automobile industries, this research comprehensively uses heat treatment and reverse isothermal extrusion technology to prepare 2024 alloy. The effects of homogenization, extrusion and post-extrusion annealing treatment on the microstructure and mechanical properties of 2024 aluminum alloy were discussed in detail. The results indicate that the grain refinement of the extruded alloy material is significant. The coarse eutectic microstructure at the grain boundaries was refined, and these grains tended to be uniformly distributed after the annealing treatment. Extruded 2024 aluminum alloy material mainly has S (Al2CuMg) and Al7Cu2Fe second phases. The appearance of a large number of S phases led to a significant improvement in the properties of the alloy with an increase in tensile strength and elongation of 176% and 547%, respectively. In addition, EBSD analysis showed a significant meritocratic growth in the extrusion direction with the appearance of Copper {112} <111> rolling weaving, which led to process hardening and the strength improvement of the alloy.
Concurrence of High Corrosion Resistance and Strength with Excellent Ductility in Ultrafine-Grained Mg-3Y Alloy
Authors: Zemková Mária , Minárik Peter , Jablonská Eva , Veselý Jozef , Bohlen Jan , Kubásek Jiří , Lipov Jan , Ruml Tomáš , Havlas Vojtěch , Král Robert
Published: October 2022

In the field of magnesium-based degradable implantable devices, the Mg-Y-RE-Zr alloying system (WE-type) has gained popularity due to its satisfying degradation rate together with mechanical strength. However, utilization of RE and Zr in the WE-type alloys was originally driven to improve Mg-based alloys for high-temperature applications in the industry, while for medical purposes, there is a question of whether the amount of alloying elements may be further optimized. For this reason, our paper presents the Mg-3Y (W3) magnesium alloy as an alternative to the WE43 alloy. This study shows that the omission of RE and Zr elements did not compromise the corrosion resistance and the degradation rate of the W3 alloy when compared with the WE43 alloy; appropriate biocompatibility was preserved as well. It was shown that the decrease in the mechanical strength caused by the omission of RE and Zr from the WE43 alloy could be compensated for by severe plastic deformation, as achieved in this study, by equal channel angular pressing. Ultrafine-grained W3 alloy exhibited compression yield strength of 362 ± 6 MPa and plastic deformation at maximum stress of 18 ± 1%. Overall, the early results of this study put forward the motion of avoiding RE elements and Zr in magnesium alloy as a suitable material for biodegradable applications and showed that solo alloying of yttrium is sufficient for maintaining desirable properties of the material at once.
Applicability of Pre-Plastic Deformation Method for Improving Mechanical Properties of Bulk Metallic Glasses
Authors: Zhou Changshan , Zhang Hezhi , Yuan Xudong , Song Kaikai , Liu Dan
Published: October 2022

Pre-plastic deformation (PPD) treatments on bulk metallic glasses (BMGs) have previously been shown to be helpful in producing multiple shear bands. In this work, the applicability of the PPD approach on BMGs with different Poisson’s ratios was validated based on experimental and simulation observations. It was found that for BMGs with high Poisson’s ratios (HBMGs, e.g., Zr56Co28Al16 and Zr46Cu46Al8), the PPD treatment can easily trigger a pair of large plastic deformation zones consisting of multiple shear bands. These PPD-treated HBMGs clearly display improved strength and compressive plasticity. On the other hand, the mechanical properties of BMGs with low Poisson’s ratios (LBMG, e.g., Fe48Cr15Mo14Y2C15B6) become worse due to a few shear bands and micro-cracks in extremely small plastic deformation zones. Additionally, for the PPD-treated HBMGs with similar high Poisson’s ratios, the Zr56Co28Al16 BMG exhibits much larger plasticity than the Zr46Cu46Al8 BMG. This phenomenon is mainly due to more defective icosahedral clusters in the Zr56Co28Al16 BMG, which can serve as nucleation sites for shear transformation zones (STZs) during subsequent deformation. The present study may provide a basis for understanding the plastic deformation mechanism of BMGs.
Selective Laser Melting and Mechanical Properties of Stainless Steels
Authors: Gatões Daniel , Alves Ricardo , Alves Bernardo , Vieira Maria Teresa
Published: October 2022

Metal additive manufacturing (AM) has been evolving in response to industrial and social challenges. However, new materials are hindered in these technologies due to the complexity of direct additive manufacturing technologies, particularly selective laser melting (SLM). Stainless steel (SS) 316L, due to its very low carbon content, has been used as a standard powder in SLM, highlighting the role of alloying elements present in steels. However, reliable research on the chemical impact of carbon content in steel alloys has been rarely conducted, despite being the most prevalent element in steel. Considering the temperatures involved in the SLM process, the laser–powder interaction can lead to a significant carbon decrease, whatever the processing atmosphere. In the present study, four stainless steels with increasing carbon content—AISI 316L, 630 (17-4PH), 420 and 440C—were processed under the same SLM parameters. In addition to roughness and surface topography, the relationship with the microstructure (including grain size and orientation), defects and mechanical properties (hardness and tensile strength) were established, highlighting the role of carbon. It was shown that the production by SLM of stainless steels with similar packing densities and different carbon contents does not oblige the changing of processing parameters. Moreover, alterations in material response in stainless steels produced under the same volumetric energy density mainly result from microstructural evolution during the process.
Exploring Hydrogen Incorporation into the Nb4AlC3 MAX Phases: Ab Initio Calculations
Authors: Fu Yudong , Li Zifeng , Gao Weihong , Zhao Danni , Huang Zhihao , Sun Bin , Yan Mufu , Liu Guotan , Liu Zihang
Published: October 2022

The Nb4AlC3 MAX phase can be regarded as a TMC structure with stacking faults, which has great potential as a novel solid hydrogen storage material. Herein, we used ab initio calculations for understanding the hydrogen incorporation into Nb4AlC3 MAX phases, including equilibrium structural characteristics, energy changes, electronic structures, bonding characteristics, and diffusion paths. According to the calculated results, H has thermal stability in the interstice of the Nb-Al layer, and the most probable insertion site is an octahedron (3-site) composed of three Nb atoms and three Al atoms. When C vacancies are introduced, the Nb-C layer has a specific storage capacity for H. In addition, Al vacancies can also be used as possible sites for H incorporation. Moreover, the introduction of vacancies significantly increase the hydrogen storage capacity of the MAX phase. According to the electronic structure and bonding characteristics, the excellent hydrogen storage ability of the Nb4AlC3 structure may be due to the formation of ionic bonds between H and Nb/Al. It is worth noting that the H-Al bond in the 1-site is a covalent bond and an ionic bond key mixture. The linear synchronous transit optimization study shows that only H diffusion in Al vacancies is not feasible. In conclusion, the Nb-Al layer in Nb4AlC3 can provide favorable conditions for the continuous insertion and subsequent extraction of H, while the vacancy structure is more suitable for H storage. Our work provides solid theoretical results for understanding the hydrogen incorporation into Nb4AlC3 MAX phases that can be helpful for the design of advanced hydrogen storage materials.
Control of Dielectric and Mechanical Properties of Styrenic Block Copolymer by Graphite Incorporation
Authors: Ciuprina Florin , Panaitescu Denis Mihaela , Enache Laura , Damian Celina Maria , Grigorescu Ramona Marina , Gabor Augusta Raluca , Nicolae Cristian Andi , Nistor Cristina Lavinia , Trusca Roxana
Published: October 2022

The structure–property relationship of dielectric elastomers, as well as the methods of improving the control of this relationship, has been widely studied over the last few years, including in some of our previous works. In this paper, we study the control, improvement, and correlation, for a significant range of temperatures, of the mechanical and dielectric properties of polystyrene-b-(ethylene-co-butylene)-b-styrene (SEBS) and maleic-anhydride-grafted SEBS (SEBS-MA) by using graphite (G) as filler in various concentrations. The aim is to analyze the suitability of these composites for converting electrical energy into mechanical energy or vice versa. The dielectric spectroscopy analysis performed in the frequency range of 10 to 1 MHz and at temperatures between 27 and 77 °C emphasized an exponential increase in real permittivity with G concentration, a low level of dielectric losses (≈10−3), as well as the stability of dielectric losses with temperature for high G content. These results correlate well with the increase in mechanical stiffness with an increase in G content for both SEBS/G and SEBS-MA/G composites. The activation energies for the dielectric relaxation processes detected in SEBS/G and SEBS-MA/G composites were also determined and discussed in connection with the mechanical, thermal, and structural properties resulting from thermogravimetric analysis, differential scanning calorimetry, Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses.
Influence of Recycled Fine Aggregate Content on Properties of Soft Soil Solidified by Industrial Waste Residue
Authors: Wang Anhui , Zhan Qiwei , Dong Wanying , Gu Weiyang , Zhou Juanlan , Pan Zhihong
Published: October 2022

The influence of recycled fine aggregate content on the properties of soft soil solidified by industrial waste residue was systematically studied. First, the addition of recycled fine aggregate may provide skeleton support, which was conducive to improving the solidification properties. Comparing the addition of recycled fine aggregate content and a composite solidification agent separately, the compressive strength increased 48.01 times and 1.32 times, respectively. Second, the composition and quantity of the hydration products were analyzed by X-ray diffraction (XRD) and thermal gravity analysis (TG/DTG). In addition to silicon dioxide and aluminum oxide, a number of new minerals, including hydrated calcium silicate, calcium hydroxide and ettringite, were produced under different recycled fine aggregate contents. The diffraction peak of hydrated calcium hydroxide was weak, which indicated that the crystallinity and relative content was low. The main reason for this was that it was consumed as the activator of the secondary hydration reaction of blast furnace slag. With the increase in recycled fine aggregate content, the total weight loss (hydration products, crystal water, impurities) increased significantly, at rates of 6.9%, 7.0%, 7.2%, 8.8% and 9.7%. The addition of recycled fine aggregate does not change the composition and quantity of the hydration products, and the increased weight loss in this part might be caused by the cement paste attached to the surface of the recycled fine aggregate. Finally, their microstructure was analyzed by scanning electron microscopy (SEM). Larger and more pores appeared in the solidification system with the increase in recycled fine aggregate, and a large amount of ettringite was prepared. An excess in recycled fine aggregate caused more pores, and the negative impact of too many pores exceeded the lifting effect of the aggregate, resulting in the decline of its mechanical properties. Therefore, there was a suitable range for the use of recycled fine aggregate, which was not more than 40%. In conclusion, recycled fine aggregate not only acts as a skeleton to improve solidification strength, but could also realize the comprehensive utilization of waste, which provided a new scheme for solid waste utilization and soft soil solidification.
Effects of Laser Forming on the Mechanical Properties and Microstructure of DP980 Steel
Authors: Dong Wenbin , Bao Le , Li Wenqi , Shin Kyoosik , Han Changsoo
Published: October 2022

Due to its high strength and good plasticity, dual-phase (DP) steel is widely used for manufacturing the structural and reinforcement components of automobiles. Therefore, it is urgent to investigate the mechanical properties and microstructure variation in DP steel after deformation, especially those subjected to hot-forming processes. In this study, the mechanical properties and microstructure of laser-formed DP980 steel plates under different laser parameters were investigated by means of monotonic tensile tests, microhardness tests, and metallographic tests. The results showed that both yield strength and tensile strength increased with increasing laser line energy in the range of 5~19 J/mm due to the increasing volume content of martensite laths. Elongation was slightly improved after the laser-forming process due to the existence of residual austenite. The average microhardness of the heat-affected zone also increased with an increase in laser line energy and reached a maximum of 412.8 HV0.2—an improvement of 23.5% compared to that of the parent material.
Experimental Study on Mechanical Properties of Concrete at Super-Early Age
Authors: Yang Qiuwei , Sun Yun , Peng Xi
Published: October 2022

Few studies have reported the cohesion and friction angle of concrete at a super early age. However, these two mechanical parameters are necessary to study the influence of engineering vibration on super-early-age concrete. In view of this, the mechanical properties of the super-early age-concrete are investigated in this work by direct shear testing. Firstly, the shear strength of the super-early-age concrete is measured by the direct shear experiment under different normal pressures at different times. Secondly, the cohesion and friction angle of the super early age concrete are calculated according to the Mohr–Coulomb criterion of failure. To overcome the great discreteness and randomness in the measured data, a new robust regression analysis algorithm is presented to replace the traditional regression analysis method to obtain more reliable and reasonable mechanical parameters. According to the experimental and theoretical analysis results, it is found that the friction angles of the super early age concrete are located in the interval of [50°, 70°]. The cohesion of the concrete is about 78.7 kPa at the initial setting state and about 190.9 kPa at the final setting state, respectively. It has been shown that the cohesion of the concrete at a super-early age tends to increase rapidly with time. The method and test results of this work can be used as a reference for relevant engineering practice. Specifically, the proposed regression method can be extended to the data analysis of other mechanical parameters of concrete, as well as other brittle materials such as rock. The test results of early concrete cohesion and friction angle can be used to analyze the adverse effects of vibration on newly cast concrete members in pile driving and blasting engineering.
Analysis of Size-Dependent Linear Static Bending, Buckling, and Free Vibration Based on a Modified Couple Stress Theory
Authors: Tang Feixiang , He Siyu , Shi Shaonan , Xue Shun , Dong Fang , Liu Sheng
Published: October 2022

The purposes of this paper are to study bending, buckling, and vibration by considering micro-scale effects using the Kirchhoff thin-plate theory and to consider small deflections, neglecting higher-order nonlinear terms. The governing equations for the bending, buckling, and vibration of the system are obtained using the equilibrium method coupled with the Kirchhoff thin-plate theory and a modified couple stress theory (MCST). The concept of the equivalent bending stiffness (EBS) of micro-thin plates is proposed to describe the scale effect. The Navier method is used to obtain analytical solutions for the bending, buckling, and free vibration of thin plates under simply supported boundary conditions with scale effects. The numerical results are presented to investigate the influence of scale effects on deflection, critical buckling load, buckling topography, and thin-plate natural frequency. The results show that the scale effect increases the equivalent stiffness of the thin plate, which leads to a decrease in deflection, a larger critical buckling load, and an increase in natural frequency, but does not affect the buckling topography. The MSCT is invalid when the thickness is greater than 10 times the scale effect parameter, thus defining the scope of application of the scale effect. This research study may contribute to the design of micro-scale devices such as MEMSs/NEMSs.
Numerical Simulation in the Melt Pool Evolution of Laser Powder Bed Fusion Process for Ti6Al4V
Authors: Xu Yixuan , Zhang Dongyun , Deng Junyuan , Wu Xuping , Li Lingshan , Xie Yinkai , Poprawe Reinhart , Schleifenbaum Johannes Henrich , Ziegler Stephan
Published: October 2022

In order to track the free interface of the melt pool and understand the evolution of the melt pool, the flow of fluid, and the interface behavior of gas and liquid, a physical model is developed by using the VOF method in this paper. Its characteristics are a combined heat source model, including a parabolic rotation and a cylindrical distribution, and a powder bed stochastic distributed model with powder particle size. The unit interface between the metallic and gas phase in the laser–powder interaction zone can only be loaded by the heat source. Only the first and second laser scanning tracks are simulated to reduce the calculation time. The simulation results show that process parameters such as laser power and scanning speed have significant effects on the fluid flow and surface morphology in the melt pool, which are in good agreement with the experimental results. Compared with the first track, the second track has larger melt pool geometry, higher melt temperature, and faster fluid flow. The melt flows intensely at the initial position due to the high flow rate in the limited melt space. Because there is enough space for the metal flow, the second track can obtain smooth surface morphology more easily compared to the first track. The melt pool temperature at the laser beam center fluctuates during the laser scanning process. This depends on the effects of the interaction between heat conduction or heat accumulation or the interaction between heat accumulation and violent fluid flow. The temperature distribution and fluid flow in the melt pool benefit the analysis and understanding of the evolution mechanism of the melt pool geometry and surface topography and further allow regulation of the L-PBF process of Ti6Al4V.
An HGA-LSTM-Based Intelligent Model for Ore Pulp Density in the Hydrometallurgical Process
Authors: Zou Guobin , Zhou Junwu , Li Kang , Zhao Hongliang
Published: October 2022

This study focused on the intelligent model for ore pulp density in the hydrometallurgical process. However, owing to the limitations of existing instruments and devices, the feed ore pulp density of thickener, a key hydrometallurgical equipment, cannot be accurately measured online. Therefore, aiming at the problem of accurately measuring the feed ore pulp density, we proposed a new intelligent model based on the long short-term memory (LSTM) and hybrid genetic algorithm (HGA). Specifically, the HGA refers to a novel optimization search algorithm model that can optimize the hyperparameters and improve the modeling performance of the LSTM. Finally, the proposed intelligent model was successfully applied to an actual thickener case in China. The intelligent model prediction results demonstrated that the hybrid model outperformed other models and satisfied the measurement accuracy requirements in the factory well.
Mid-Infrared Broadband Achromatic Metalens with Wide Field of View
Authors: Jiang Yurong , Cui Cheng , Zhao Jinmin , Hu Bin
Published: October 2022

Metasurfaces have the ability to flexibly control the light wavefront, and they are expected to fill the gaps of traditional optics. However, various aberrations pose challenges for the application of metasurfaces in the wide angle and wide spectral ranges. The previous multi-aberration simultaneous optimization works had shortcomings such as large computational load, complex structure, and low generality. Here, we propose a metalens design method that corrects both monochromatic and chromatic aberrations simultaneously. The monochromatic aberration-corrected phase distribution is obtained by the optical design, and the chromatic aberration is reduced by using the original search algorithm combined with dispersion engineering. The designed single-layered wide-angle achromatic metalens has a balanced and efficient focusing effect in the mid-infrared band from 3.7 μm to 5 μm and a wide angle of ±30°. The design method proposed has the advantages of low computational load, wide application range, and easy experimental fabrication, which provides new inspiration for the development of generalized software for the design and optimization of metasurfaces.
Synthesis and Characterization of the Mixed Metal Oxide of ZnO-TiO2 Decorated by Polyaniline as a Protective Film for Acidic Steel Corrosion: Experimental, and Computational Inspections
Authors: Al-Masoud May Ahmed , Khalaf Mai M. , Gouda Mohamed , Dao Van-Duong , Mohamed Ibrahim M. A. , Shalabi Kamal , Abd El-Lateef Hany M.
Published: October 2022

In this work, the preparation, characterization, and evaluation of a novel nanocomposite using polyaniline (PANi) functionalized bi-metal oxide ZnO-TiO2 (ZnTiO@PANi) as shielding film for carbon steel (CS)-alloy in acidic chloride solution at 298 K was studied. Different spectroscopic characterization techniques, such as UV-visible spectroscopy, dynamic light scattering (DLS), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR) approaches, as well as other physicochemical methods, such as X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), and field emission scanning electron microscope (FESEM), were used to describe the produced nanocomposites. The significance of these films lies in the ZnO-TiO2 nanoparticle’s functionalization by polyaniline, a material with high conductivity and electrochemical stability in acidic solutions. The mechanistic findings of the corrosion inhibition method were obtained by the use of electrochemical methods including open-circuit potentials (OCP) vs. time, potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS). The results indicate that the synthesized ZnTiO@PANi is a powerful acidic corrosion inhibitor, and its inhibition effectiveness is 98.86% in the presence of 100 ppm. Additionally, the charge transfer resistance (Rp) value augmented from 51.8 to 432.7, and 963.7 Ω cm2 when the dose of PANi, and ZnTiO@PANi reached 100 ppm, respectively. The improvement in Rp and inhibition capacity values with an increase in nanocomposite dose is produced by the nanocomposite additives covering a larger portion of the surface, resulting in a decrease in alloy corrosion. By identifying the probable regions for molecule adsorption on the steel substrate, theoretical and computational studies provided significant details regarding the corrosion mitigation mechanism. The possibility of substituting old poisonous small substances with inexpensive and non-hazardous polymeric materials as shielding layers for utilization in the oilfield sectors is an important suggestion made by this research.