bluuebunny/crossref_metadata_2025 huggingface dataset:
Treatment of Mechanical Corneal Wounds Emergencies during the COVID-19 Pandemic: Absorbable 10-0 Vicryl (Polyglactin 910) Sutures as a Suitable Strategy
Authors: Abihaidar Nicolas , Thuret Gilles , Gain Philippe , Garcin Thibaud
Published: May 2022

Background—The COVID-19 pandemic has changed our standard practices: operating rooms were only available for functional emergencies and outpatient visits were drastically reduced in favor of telemedicine. Aim: To report the personalized “one-shot” surgery using absorbable 10-0 Vicryl (V10-0) or polyglactin 910 monofilament in mechanical corneal injuries from February 2020 to December 2021. Methods—Prospective case series with at least 12-months’ follow-up, in a French university hospital. Among the overall population of open or closed-globe emergencies (n = 40), non-penetrating corneal lamellar lacerations (long axis > 2 mm) in zone 1 (OTC group) were treated with V10-0 suture(s) (n = 10), replacing traditional non-absorbable 10-0 nylon suture(s) or medical options in first line. The outpatient visits were performed on day (D)10, month (M)2, M6 then every six months. One interim visit by phone teleconsultation was scheduled between D10 and M2, and other(s) as needed. The main outcome was best-corrected visual acuity (BCVA) at M6. Secondary outcomes included mainly corneal astigmatism (CA) at M6 complications. Results—Among the ten corneal wounds, there were three children (30%), eight domestic accidents (80%), three eyes with metallic foreign bodies (30%), four open-globe injuries (40%), and nine eyes that received high-speed projectiles or sharp objects (90%). The complete V10-0 suture(s) absorption occurred in all eyes between D10 and M2. At M6, mean far and near BCVA decreased from 0.680 ± 0.753 and 0.490 ± 0.338 preoperatively to 0.050 ± 0.071 and 0.220 ± 0.063 logMAR (p = 0.019 and p = 0.025 respectively), mean CA decreased from 4.82 ± 3.86 preoperatively to 1.15 ± 0.66 diopters (p = 0.008). BCVA and CA were unchanged thereafter. No serious adverse event nor repeated surgery occurred. The mean number of teleconsultations was 1.20 ± 0.63 without an additional nonscheduled outpatient visit. Conclusions—The absorbable V10-0 sutures might be a safe and effective alternative for eligible corneal wounds, while reducing the number of outpatient visits, especially for children (no suture removal). The COVID-19 pandemic highlighted that they are ideally suited to logistical challenges.
Linking Supply Chain Disruption Orientation to Supply Chain Resilience and Market Performance with the Stimulus–Organism–Response Model
Authors: Stephens Aaron Rae , Kang Minhyo , Robb Charles Arthur
Published: May 2022

Since 2020, supply chain disruptions have emerged as an ever-present challenge. This research provides a glimpse into the organizational structures that develop supply chain resilience and market performance amid continuous supply chain disruptions. Utilizing psychosomatic variables and empirical modeling, a model was constructed through a review of extant literature and tested with PLS-SEM analysis. Uniquely, this research model is framed with the stimulus–organism–response model; thus, placing a firm within the context of a tumultuous environment where stimuli elicit responses from an organization that behaves as an organism. Results demonstrate that organizational culture plays a critical role in developing supply chain resilience amid supply chain dynamism. Market performance was also developed but only through supply chain resilience; supply chain disruption orientation alone did not improve market performance. Mediation effects highlight the importance of supply chain disruption orientation, a strategic orientation that cements an organization’s ability to develop supply chain resilience.
Climate Adaptation Heuristic Planning Support System (HPSS): Green-Blue Strategies to Support the Ecological Transition of Historic Centres
Authors: Trovato Maria Rosa , Cappello Cheren
Published: May 2022

The issue of climate has posed major and urgent challenges for the global community. The European Green Deal sets out a new growth strategy aimed at turning the European Union into a just and prosperous society, with a modern, resource-efficient, and competitive economy, which will no longer generate net greenhouse gas emissions by 2050. Cities in this context are committed on several fronts to rapid adaptation to improve their resilience capacity. The historic centre is the most vulnerable part of a city, with a reduced capacity for adaptation, but also the densest of values, which increase the complexity of the challenge. This study proposes an integrated tool, Heuristic Planning Support System (HPSS), aimed at exploring green-blue strategies for the historic centre. The tool is integrated with classic Planning Support System (PSS), a decision process conducted from the perspective of heuristic approach and Geographic Information System (GIS). It comprises modules for technical assessment, environmental assessment Life Cycle Assessment (LCA), economic assessment Life Cycle Cost (LCC), Life Cycle Revenues (LCR), and Discounted Cash Flow Analysis (DCFA) extended to the life cycle of specific interventions, the Multi-Attribute Value Theory (MAVT) for the assessment of energy, environmental, identity, landscape, and economic values. The development of a tool to support the ecological transition of historic centres stems from the initiative of researchers at the University of Catania, who developed it based on the preferences expressed by a group of decision makers, that is, a group of local administrators, scholars, and professionals. The proposed tool supports the exploration of green-blue strategies identified by decision makers and the development of the plan for the historic district of Borgata di Santa Lucia in Syracuse.
Contribution of Incorporating the Phosphorus Cycle into TRIPLEX-CNP to Improve the Quantification of Land Carbon Cycle
Authors: Ding Juhua , Zhu Qiuan , Li Hanwei , Zhou Xiaolu , Liu Weiguo , Peng Changhui
Published: May 2022

Phosphorus (P) is a key and a limiting nutrient in ecosystems and plays an important role in many physiological and biochemical processes, affecting both terrestrial ecosystem productivity and soil carbon storage. However, only a few global land surface models have incorporated P cycle and used to investigate the interactions of C-N-P and its limitation on terrestrial ecosystems. The overall objective of this study was to integrate the P cycle and its interaction with carbon (C) and nitrogen (N) into new processes model of TRIPLEX-CNP. In this study, key processes of the P cycle, including P pool sizes and fluxes in plant, litter, and soil were integrated into a new model framework, TRIPLEX-CNP. We also added dynamic P:C ratios for different ecosystems. Based on sensitivity analysis results, we identified the phosphorus resorption coefficient of leaf (rpleaf) as the most influential parameter to gross primary productivity (GPP) and biomass, and determined optimal coefficients for different plant functional types (PFTs). TRIPLEX-CNP was calibrated with 49 sites and validated against 116 sites across eight biomes globally. The results suggested that TRIPLEX-CNP performed well on simulating the global GPP and soil organic carbon (SOC) with respective R2 values of 0.85 and 0.78 (both p < 0.01) between simulated and observed values. The R2 of simulation and observation of total biomass are 0.67 (p < 0.01) by TRIPLEX-CNP. The overall model performance had been improved in global GPP, total biomass and SOC after adding the P cycle comparing with the earlier version. Our work represents the promising step toward new coupled ecosystem process models for improving the quantifications of land carbon cycle and reducing uncertainty.
The Impacts of Microgravity on Bacterial Metabolism
Authors: Sharma Gayatri , Curtis Patrick D.
Published: May 2022

The inside of a space-faring vehicle provides a set of conditions unlike anything experienced by bacteria on Earth. The low-shear, diffusion-limited microenvironment with accompanying high levels of ionizing radiation create high stress in bacterial cells, and results in many physiological adaptations. This review gives an overview of the effect spaceflight in general, and real or simulated microgravity in particular, has on primary and secondary metabolism. Some broad trends in primary metabolic responses can be identified. These include increases in carbohydrate metabolism, changes in carbon substrate utilization range, and changes in amino acid metabolism that reflect increased oxidative stress. However, another important trend is that there is no universal bacterial response to microgravity, as different bacteria often have contradictory responses to the same stress. This is exemplified in many of the observed secondary metabolite responses where secondary metabolites may have increased, decreased, or unchanged production in microgravity. Different secondary metabolites in the same organism can even show drastically different production responses. Microgravity can also impact the production profile and localization of secondary metabolites. The inconsistency of bacterial responses to real or simulated microgravity underscores the importance of further research in this area to better understand how microbes can impact the people and systems aboard spacecraft.
Females with Diabetes Mellitus Increased the Incidence of Premenstrual Syndrome
Authors: Huang Yao-Ming , Chien Wu-Chien , Cheng Chun-Gu , Chang Yin-Han , Chung Chi-Hsiang , Cheng Chun-An
Published: May 2022

Background: Premenstrual syndrome (PMS) is a multifactorial disorder caused by hormone and autonomic imbalance. In our study, hyperglycemia-induced insulin secretion increased progesterone secretion and progressive autonomic imbalance. The young patients with diabetes mellitus (DM) revealed hypo-parasympathetic function and hypersympathetic function compared with nondiabetic controls. Young female patients with DM with higher blood sugar and autonomic malfunction may be associated with PMS. However, there is a lack of evidence about DM in females related to PMS. We evaluated female patients with DM who subsequently followed PMS in a retrospective cohort study. Methods: We retrieved data from the National Health Insurance Research Database in Taiwan. Female patients with DM between 20 and 50 years old were assessed by the International Classification of Disease, 9 Revision, Clinical Modification (ICD-9-CM) disease code of 250. Patients who were DM-free females were fourfold matched to the control group by age and disease index date. The ICD-9-CM disease code of 625.4 identified the incidence of PMS followed by the index date as events. The possible risk factors associated with PMS were detected with a Cox proportional regression. Results: DM was a significant risk factor for PMS incidence with an adjusted hazard ratio of 1.683 (95% confidence interval: 1.104–2.124, p < 0.001) in females after adjusting for age, other comorbidities, season, urbanization status of patients and the hospital status of visiting. Conclusions: This study noted an association between DM and PMS in female patients. Healthcare providers and female patients with DM must be aware of possible complications of PMS, aggressive glycemic control, decreased hyperglycemia and autonomic dysfunction to prevent this bothersome disorder.
Beneficial Effects of Pulmonary Vasodilators on Pre-Capillary Pulmonary Hypertension in Patients with Chronic Kidney Disease on Hemodialysis
Authors: Kimuro Keiji , Hosokawa Kazuya , Abe Kohtaro , Masaki Kohei , Imakiire Satomi , Sakamoto Takafumi , Tsutsui Hiroyuki
Published: May 2022

Background: In patients with chronic kidney disease (CKD) on hemodialysis, comorbid pulmonary hypertension (PH) aggravates exercise tolerance and eventually worsens the prognosis. The treatment strategy for pre-capillary PH, including combined pre- and post-capillary PH (Cpc-PH), has not been established. Objectives: This study aimed to evaluate the impact of pulmonary vasodilators on exercise tolerance and pulmonary hemodynamics in patients with CKD on hemodialysis. Methods and Results: The medical records of 393 patients with suspected PH who underwent right heart catheterization were reviewed. Of these, seven patients had isolated pre-capillary PH and end-stage CKD on hemodialysis. Pulmonary vasodilators decreased pulmonary vascular resistance from 5.9 Wood units (interquartile range (IQR), 5.5–7.6) at baseline to 3.1 Wood units (IQR, 2.6–3.3) post-treatment (p = 0.02) as well as increased pulmonary capillary wedge pressure from 10 mmHg (IQR, 7–11) to 11 mmHg (IQR, 8–16) (p = 0.04). Pulmonary vasodilators increased the World Health Organization functional class I or II from 0% to 100% (p = 0.0002) and the 6 min walk distance from 273 m (IQR, 185–365) to 490 m (IQR, 470–550) (p = 0.03). Conclusions: Pulmonary vasodilators for PH in patients with CKD on hemodialysis decrease pulmonary vascular resistance and eventually improve exercise tolerance. Pulmonary vasodilators may help hemodialysis patients with pre-capillary PH, although careful management considering the risk of pulmonary edema is required.
Fractal Analysis of a Non-Newtonian Fluid Flow in a Rough-Walled Pipe
Authors: Bouchendouka Abdellah , Fellah Zine El Abiddine , Larbi Zakaria , Louna Zineeddine , Ogam Erick , Fellah Mohamed , Depollier Claude
Published: May 2022

The fully developed laminar flow of a viscous non-Newtonian fluid in a rough-walled pipe is considered. The fluid rheology is described by the power–law model (covering shear thinning, Newtonian, and shear thickening fluids). The rough surface of the pipe is considered to be fractal, and the surface roughness is measured using surface fractal dimensions. The main focus of this study lies in the theoretical investigation of the influence of the pipe surface roughness on the velocity profile and the Darcy friction factor of an incompressible non-Newtonian fluid. The plotted results demonstrate that shear thinning fluids are the most sensitive to the surface roughness compared with Newtonian and shear thickening fluids. For a particular value of the surface fractal dimension, there exists an intersection point where shear thinning, Newtonian, and shear thickening fluids behave the same way regarding the amplitude of the velocity profile and the friction factor. This approach has a variety of potential applications, for instance fluid dynamics in hydrology, blood flow in the cardiovascular system, and many industrial applications.
Experimental Research on the Preparation of K2CO3/Expanded Vermiculite Composite Energy Storage Material
Authors: Zou Dequan , Yue Xiangji , He Tianyi , Ding Jianan , Ba Dechun
Published: May 2022

Thermochemical adsorption energy storage is a potential energy utilization technology. Among these technologies, the composite energy storage material prepared by K2CO3 and expanded vermiculite (EVM) shows excellent performance. In this paper, the influence of the preparation process using the impregnation method and vacuum impregnation method on K2CO3/EVM composite material is studied. The preparation plan is further optimized with the solution concentration and the expanded vermiculite particle size as variables. In the experiment, mercury intrusion porosimetry (MIP) is used to measure the porosity and other parameters. Additionally, with the help of scanning electron microscopy (SEM), the morphological characteristics of the materials are obtained from a microscopic point of view. The effects of different preparation parameters are evaluated by comparing the experimental results. The results show that the K2CO3 specific gravity of the composite material increases with the increase of the vacuum degree, up to 70.440 wt.% (the vacuum degree is 6.7 kPa). Expanded vermiculite with a large particle size (3~6 mm) can carry more K2CO3, and content per cubic centimeter of K2CO3 can be as high as 0.466 g.
Microstructure Evolution and Its Correlation with Performance in Nitrogen-Containing Porous Carbon Prepared by Polypyrrole Carbonization: Insights from Hybrid Calculations
Authors: Li Shanshan , Bian Fang , Wu Xinge , Sun Lele , Yang Hongwei , Meng Xiangying , Qin Gaowu
Published: May 2022

The preparation of nitrogen-containing porous carbon (NCPC) materials by controlled carbonization is an exciting topic due to their high surface area and good conductivity for use in the fields of electrochemical energy storage and conversion. However, the poor controllability of amorphous porous carbon prepared by carbonization has always been a tough problem due to the unclear carbonation mechanism, which thus makes it hard to reveal the microstructure–performance relationship. To address this, here, we comprehensively employed reactive molecular dynamics (ReaxFF-MD) simulations and first-principles calculations, together with machine learning technologies, to clarify the carbonation process of polypyrrole, including the deprotonation and formation of pore structures with temperature, as well as the relationship between microstructure, conductance, and pore size. This work constructed ring expressions for PPy thermal conversion at the atomic level. It revealed the structural factors that determine the conductivity and pore size of carbonized products. More significantly, physically interpretable machine learning models were determined to quantitatively express structure factors and performance structure–activity relationships. Our study also confirmed that deprotonation preferentially occurred by desorbing the dihydrogen atom on nitrogen atoms during the carbonization of PPy. This theoretical work clearly reproduces the microstructure evolution of polypyrrole on an atomic scale that is hard to do via experimentation, thus paving a new way to the design and development of nitrogen-containing porous carbon materials with controllable morphology and performance.
Infill Density Influence on Mechanical and Thermal Properties of Short Carbon Fiber-Reinforced Polyamide Composites Manufactured by FFF Process
Authors: Chicos Lucia-Antoneta , Pop Mihai Alin , Zaharia Sebastian-Marian , Lancea Camil , Buican George Razvan , Pascariu Ionut Stelian , Stamate Valentin-Marian
Published: May 2022

In three-dimensional (3D) printing, one of the main parameters influencing the properties of 3D-printed materials is the infill density (ID). This paper presents the influence of ID on the microstructure, mechanical, and thermal properties of carbon fiber-reinforced composites, commercially available, manufactured by the Fused Filament Fabrication (FFF) process. The samples were manufactured using FFF by varying the infill density (25%, 50%, 75%, and 100%) and were subjected to tensile tests, three-point bending, and thermal analyses by Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). It was shown that the samples with 100% ID had the highest values of both tensile, 90.8 MPa, and flexural strengths, 114 MPa, while those with 25% ID had the lowest values of 56.4 MPa and 62.2 MPa, respectively. For samples with infill densities of 25% and 50%, the differences between the maximum tensile and flexural strengths were small; therefore, if the operating conditions of the components allow, a 25% infill density could be used instead of 50%. After DSC analysis, it was found that the variation in the ID percentage determined the change in the glass transition temperature from 49.6 °C, for the samples with 25% ID, to 32.9 °C, for those with 100% ID. TGA results showed that the samples with IDs of 75% and 100% recorded lower temperatures of onset degradation (approximately 344.75 °C) than those with infill densities of 25% and 50% (348.5 °C, and 349.6 °C, respectively).
Finite Element Simplifications and Simulation Reliability in Single Point Incremental Forming
Authors: Pepelnjak Tomaž , Sevšek Luka , Lužanin Ognjan , Milutinović Mladomir
Published: May 2022

Single point incremental forming (SPIF) is one of the most promising technologies for the manufacturing of sheet metal prototypes and parts in small quantities. Similar to other forming processes, the design of the SPIF process is a demanding task. Nowadays, the design process is usually performed using numerical simulations and virtual models. The modelling of the SPIF process faces several challenges, including extremely long computational times caused by long tool paths and the complexity of the problem. Path determination is also a demanding task. This paper presents a finite element (FE) analysis of an incrementally formed truncated pyramid compared to experimental validation. Focus was placed on a possible simplification of the FE process modelling and its impact on the reliability of the results obtained, especially on the geometric accuracy of the part and bottom pillowing effect. The FE modelling of SPIF process was performed with the software ABAQUS, while the experiment was performed on a conventional milling machine. Low-carbon steel DC04 was used. The results confirm that by implementing mass scaling and/or time scaling, the required calculation time can be significantly reduced without substantially affecting the pillowing accuracy. An innovative artificial neural network (ANN) approach was selected to find the optimal values of mesh size and mass scaling in term of minimal bottom pillowing error. However, care should be taken when increasing the element size, as it has a significant impact on the pillow effect at the bottom of the formed part. In the range of selected mass scaling and element size, the smallest geometrical error regarding the experimental part was obtained by mass scaling of 19.01 and tool velocity of 16.49 m/s at the mesh size of 1 × 1 mm. The obtained results enable significant reduction of the computational time and can be applied in the future for other incrementally formed shapes as well.
Microfluidic Fabrication and Thermal Properties of Microencapsulated N-Hexadecane with a Hybrid Polymer Shell for Thermal Energy Storage
Authors: Yang Luxi , Dai Linchuan , Ye Lu , Yang Rui , Lu Yangcheng
Published: May 2022

In this study, a strategy based on microfluidic method is developed toward a facile fabrication of phase change material microcapsules with uniform and controllable particle size as well as high encapsulation ratio and thermal stability. N-hexadecane, as a phase change material, was successfully encapsulated by a hybrid shell of poly (methyl methacrylate) and polyurea. The fabrication process includes the following three steps: (1) Formation of oil-in-water droplets with uniform micron size in the microfluidic chip; (2) formation of the first polyurea shell to encapsulate droplets by fast interfacial polymerization when the droplets pass through the coiled transport microchannel; and (3) completion of free radical polymerization of methyl methacrylate inside the microspheres by heating to form the hybrid microcapsule shell. The average size, encapsulation ratio, and phase change enthalpy of microcapsules changed by varying the flow rate of the dispersion phase and raw material composition. The highest melting enthalpy of 222.6 J g−1 and encapsulation ratio of 94.5% of the microcapsule were obtained when the flow rates of the continuous and dispersion fluids were 600 μL min−1 and 24 μL min−1, respectively. It is shown that the phase change material microcapsules were stable after 50 heating/cooling cycles.
Investigation of Surface Integrity Induced by Various Finishing Processes of AISI 52100 Bearing Rings
Authors: Jouini Nabil , Revel Philippe , Thoquenne Guillaume
Published: May 2022

Surface integrity induced by finishing processes significantly affects the functional performance of machined components. In this work, three kinds of finishing processes, i.e., precision hard turning, conventional grinding, and sequential grinding and honing, were used for the finish machining of AISI 52100 bearing steel rings. The surface integrity induced by these finishing processes was studied via SEM investigations and residual stress measurements. To investigate rolling contact fatigue performance, contact fatigue tests were performed on a twin-disc testing machine. As the main results, the SEM observations show that precision hard turning and grinding introduce microstructural alterations. Indeed, in precision hard turning, a fine white layer (<1 μm) is observed on the top surface, followed by a thermally affected zone in the subsurface, and in grinding only, a white layer with 5 μm thickness is observed. However, no microstructural changes are found after sequential grinding and honing processes. White layers induced by precision hard turning and grinding possess compressive residual stresses. Grinding and sequential grinding and honing processes generate similar residual stress distributions, which are maximum and compressive at the machined surface and tensile at the subsurface depth of 15 μm. Precision hard turning generates a “hook”-shaped residual stress profile with maximum compressive value at the subsurface depth and thus contributes as a prenominal factor to the obtainment of the longest fatigue life with respect to other finishing processes. Due to the high quality of surface roughness (Ra = 0.05 μm), honing post grinding improves the fatigue life of bearing rings by 2.6 times in comparison with grinding. Subsurface compressive residual stresses, as well as low surface roughness, are key parameters for extending bearing fatigue life.
Three-Dimensional Smooth Particle Hydrodynamics Modeling and Experimental Analysis of the Ballistic Performance of Steel-Based FML Targets
Authors: Kubit Andrzej , Trzepieciński Tomasz , Kiciński Radosław , Jurczak Kamil
Published: May 2022

In this paper, shields made of 1.3964 stainless steel bonded to a fiber laminate were subjected to ballistic impact response of 7.62 × 51 mm ŁPS (light projectile with a lead core) projectiles. Additionally, between the steel sheet metal and the laminate, a liquid-filled bag was placed, which was a mixture of ethylene glycol (C2H6O2) with 5 wt.% SiO2 nanopowder. Numerical modeling of the projectile penetrating the samples was carried out using the finite element method in the Abaqus program. The elasto-plastic behavior of the projectile material and the component layers of the shields was taken into account. Projectile penetration through glycol-filled bag has been performed using the smooth particle hydrodynamics technique. The morphology of the penetration channel was also analyzed using a scanning electron microscope. For the shield variant with a glycol-filled bag between the steel and laminate plates, the inlet speed of projectile was 834 m/s on average, and 366 m/s behind the sample. For the variant where there was no glycol-filled bag between the steel and laminate plates, the inlet and outlet average velocities were 836 m/s, after 481 m/s, respectively. Referring to the steel-glycol-laminate and steel-laminate variants, it can be concluded that the laminate-glycol-laminate is more effective.
Mechanical Behavior and Structural Characterization of a Cu-Al-Ni-Based Shape-Memory Alloy Subjected to Isothermal Uniaxial Megaplastic Compression
Authors: Pushin Vladimir , Kuranova Nataliya , Svirid Alexey E. , Ustyugov Yurii
Published: May 2022

For the first time, uniaxial megaplastic compression was successfully applied to a polycrystalline shape-memory Cu-Al-Ni-based alloy. The samples before and after uniaxial megaplastic compression were examined by methods of X-ray diffraction, optical, electron transmission, and scanning microscopy. The temperature dependences of electrical resistance and the mechanical properties of the alloys under uniaxial tension were also measured. The mechanical behavior under uniaxial megaplastic compression in isothermal conditions in the range of 300–1073 K was studied using the Instron 8862 electric testing machine. The microstructure, phase composition, and martensitic transformations in the eutectoid alloy (Cu-14wt.%Al–4 wt.%Ni) were studied. The radical refinement of the grain structure of the initial hardened D03 austenite was found under controlled isothermal compression, due to dynamic recrystallization in the temperature range 673–1073 K and velocities of 0.5–5 mm/min. Compression at 873–1073 K was accompanied by simultaneous partial pro-eutectoid decomposition with the precipitation of the γ2 phase. Compression at temperatures of 673 and 773 K—that is, below the eutectoid decomposition temperature (840 K)—was accompanied by the precipitation of disperse γ2 and α phases, and ultradisperse B2’ particles. Cooling of the deformed alloy to room temperature after performing each regime of compression led to thermoelastic martensitic transformation, together with the precipitation of the β′ and γ′ phases. The formation of a fine-grained structure produced an unusual combination of strength and plasticity of the initially brittle alloy both under controlled uniaxial compression, and during subsequent tensile tests at room temperature.
Effect of Ultrasonic-Assisted Modification Treatment on the Microstructure and Properties of A356 Alloy
Authors: Hu Xinyi , Song Dongfu , Wang Huiping , Jia Yiwang , Zou Haiping , Chen Mingjuan
Published: May 2022

Ultrasonic treatment was applied to an A356 aluminum melt with different modifiers, and the effects of ultrasonic treatment on the structure and properties of the A356 alloy were studied. The results showed that α-Al was effectively refined with different ultrasonic modification treatments. In particular, ultrasonic treatment showed the most obvious refinement with macroscopic grains of unmodified alloy and optimized the refinement of secondary dendrite arm spacings in the Sr/Ce synergistic alloys. The eutectic Si of the unmodified A356 alloy had no obvious change after the ultrasonic treatment, but the branch diameter of the eutectic Si reduced in the Sr and Sr/Ce modification alloys after the ultrasonic treatment. The ultrasonic treatment significantly improved the ultimate tensile strength and elongation of the as-cast A356 alloy with the unmodified material, which was due to refinement of the α-Al grains by the ultrasonic treatment. After the T6 heat treatment, the ultimate tensile strength values of the alloys showed no obvious change due to the ultrasonic treatment, but the plasticity of the alloy was significantly improved. Mg2Si precipitation was the dominant strengthening mechanism during the T6 heat treatment, while the plasticity was determined by the size and distribution of the eutectic Si. Acoustic cavitation caused by the ultrasound-activated impurities and the induced heterogeneous nucleation and supercooled nucleation in the groove melt was the main cause of the α-Al refinement, the eutectic Si modification and the improvement in the mechanical properties.
Strengthening of 0.18 wt % C Steel by Cold Differential Speed Rolling
Authors: Kang Jee-Hyun , Ko Young-Gun
Published: May 2022

Steel sheets containing 0.18 wt % C were deformed by differential speed rolling (DSR) up to four passes and compared to the steel sheets processed by equal speed rolling (ESR). Not only microstructure, but also mechanical properties and rolling load, were studied, which enlightens the relationship between microstructure, mechanical properties, and rolling load. Moreover, microstructure and properties resulting from ESR were systematically compared. During the rolling deformation, coarse grains were elongated first parallel to the rolling direction, and ultrafine grains were subsequently formed via continuous dynamic recrystallization. Microstructural analysis revealed that DSR was more effective than ESR in terms of achieving grain refinement and microstructure homogeneity. High-angle grain boundaries surrounding the ultrafine grains contributed to grain boundary strengthening, resulting in a dramatic increase in both hardness and strength after DSR. Although the steel was strengthened by rolling, the rolling load firstly increased and subsequently decreased as the number of passes increased, and lower force was required during DSR than during ESR. These can be explained by considering deformation volume and sticking friction.
Study on Corrosion Resistance and Conductivity of TiMoN Coatings with Different Mo Contents under Simulated PEMFC Cathode Environment
Authors: Jin Jie , Cao Rui , Zhang Jinzhou , Tao Yi , Tian Xu , Kou Xianli
Published: May 2022

TiMoN coatings with different Mo contents on a SS316L substrate are deposited by using closed field unbalanced magnetron sputtering ion plating (CFUMSIP) technology to enhance the corrosion resistance and durability of stainless steel (SS) bipolar plates (BPs) in proton exchange membrane fuel cell (PEMFC) during the start-up/shut-down process. The electrochemical test results illustrate that TiMoN-4A coating has extremely good corrosion resistance compared to other coatings. The potentiostat polarization (+0.6 VSCE) tests indicate that the corrosion current density (Icorr) of TiMoN-4A coating is 5.22 × 10−7A cm−2, which meets the department of energy 2020 targets (DOE, ≤1 × 10−6 A cm−2). Otherwise, TiMoN-4A coating also exhibits the best corrosion resistance and stability in potentiostatic polarization, electrochemical impedance spectroscopy (EIS), and high potential (+1.2VSCE) polarization tests. The interfacial contact resistance (ICR) measurement results show that TiMoN-4A coating has the minimum ICR of 9.19 mΩ·cm2, which meets the DOE 2020 targets (≤10 mΩ·cm2).
Prediction of Medical Conditions Using Machine Learning Approaches: Alzheimer’s Case Study
Authors: Stoleru Georgiana Ingrid , Iftene Adrian
Published: May 2022

Alzheimer’s Disease (AD) is a highly prevalent condition and most of the people suffering from it receive the diagnosis late in the process. The diagnosis is currently established following an evaluation of the protein biomarkers in cerebrospinal fluid (CSF), brain imaging, cognitive tests, and the medical history of the individuals. While diagnostic tools based on CSF collections are invasive, the tools used for acquiring brain scans are expensive. Taking these into account, an early predictive system, based on Artificial Intelligence (AI) approaches, targeting the diagnosis of this condition, as well as the identification of lead biomarkers becomes an important research direction. In this survey, we review the state-of-the-art research on machine learning (ML) techniques used for the detection of AD and Mild Cognitive Impairment (MCI). We attempt to identify the most accurate and efficient diagnostic approaches, which employ ML techniques and therefore, the ones most suitable to be used in practice. Research is still ongoing to determine the best biomarkers for the task of AD classification. At the beginning of this survey, after an introductory part, we enumerate several available resources, which can be used to build ML models targeting the diagnosis and classification of AD, as well as their main characteristics. After that, we discuss the candidate markers which were used to build AI models with the best results in terms of diagnostic accuracy, as well as their limitations.
A Rescue Use of ECPELLA for Sepsis-Induced Cardiogenic Shock Followed by Mitral Valve Replacement
Authors: Nakamura Makiko , Imamura Teruhiko , Oshima Akira , Sobajima Mitsuo , Yokoyama Shigeki , Doi Toshio , Fukahara Kazuaki , Kinugawa Koichiro
Published: May 2022

The use of veno-arterial extracorporeal membrane oxygenation (ECMO) in patients with sepsis-induced cardiogenic shock has been reported, but the clinical implication of the Impella percutaneous axial-flow left ventricular assist device for such patients remains unknown. We had a 37-year-old man with septic shock and severely reduced cardiac function. Veno-arterial ECMO and concomitant Impella CP support ameliorated his end-organ dysfunction and achieved cardiac recovery, whereas severe mitral valve regurgitation due to chordal rupture developed later. Mitral valve replacement concomitant with ECMO removal as well as an Impella upgrade successfully treated the patient. ECMO and Impella support might be an effective therapeutic strategy for the bridge to recovery in patients with sepsis-induced cardiogenic shock; however, paying attention to mitral chordal rupture is highly encouraged.
Influence of Degassing Treatment on the Ink Properties and Performance of Proton Exchange Membrane Fuel Cells
Authors: Liu Pengcheng , Yang Daijun , Li Bing , Zhang Cunman , Ming Pingwen
Published: May 2022

Degradation occurs in catalyst inks because of the catalytic oxidation of the solvent. Identification of the generation process of impurities and their effects on the properties of HSC ink and LSC ink is crucial in mitigating them. In this study, gas chromatography-mass spectrometry (GC-MS) and cyclic voltammetry (CV) showed that oxidation of NPA and EA was the primary cause of impurities such as acetic acid, aldehyde, propionic acid, propanal, 1,1-dipropoxypropane, and propyl propionate. After the degassing treatment, the degradation of the HSC ink was suppressed, and the concentrations of acetic acid, propionic acid, and propyl propionate plummeted from 0.0898 wt.%, 0.00224 wt.%, and 0.00046 wt.% to 0.0025 wt.%, 0.0126 wt.%, and 0.0003 wt.%, respectively. The smaller particle size and higher zeta potential in the degassed HSC ink indicated the higher utilization of Pt, thus leading to optimized mass transfer in the catalyst layer (CL) during working conditions. The electrochemical performance test result shows that the MEA fabricated from the degassed HSC ink had a peak power density of 0.84 W cm−2, which was 0.21 W cm−2 higher than that fabricated from the normal HSC ink. However, the introduction of propionic acid in the LSC ink caused the Marangoni flux to inhibit the coffee ring effect and promote the uniform deposition of the catalyst. The RDE tests indicated that the electrode deposited from the LSC ink with propionic acid possessed a mass activity of 84.4 mA∙mgPt−1, which was higher than the 60.5 mA∙mgPt−1 of the electrode deposited from the normal LSC ink.
Faceting and Twin–Twin Interactions in {1121} and {1122} Twins in Titanium
Authors: Barrett Christopher , Martinez Jose , Nitol Mashroor
Published: May 2022

Twin–twin interactions are an important component of the microstructural evolution of hexagonal close-packed metals undergoing plasticity. These interactions are prevalent because of the predominance of twinning due to limited easy slip modes. Despite their importance, the complexities of the atomic-scale behavior of interacting twins has limited robust characterization. Using interfacial defect theory, we developed a three-dimensional model of twin–twin interactions, double twinning and other complex interfacial reactions that occur between twins acting on different interface planes. Using molecular dynamics, {1122} and {1121} twins in titanium were activated and produced facets, twin–twin interactions and double twins that we characterized with our model. The results showed excellent agreement between the molecular dynamics results and the model. Surprisingly, some highly ordered and mobile boundaries can be produced by these complex reactions, which could provide important insights for higher scale models of plasticity.
Effect of Different Heat Treatments on Tensile Properties and Unnotched and Notched Fatigue Strength of Cold Work Tool Steel Produced by Powder Metallurgy
Authors: Morri Alessandro , Ceschini Lorella , Messieri Simone
Published: May 2022

The present study investigates the effect of two heat treatments on the microstructure, the tensile and the fatigue properties of a powder metallurgy tool steel that has undergone two heat treatments: quenching and multiple tempering (conventional for powder metallurgy tool steel), and quenching and multiple tempering with an intermediate cryogenic step at −80 °C (new solution). The findings of the research indicated that the new heat treatment promotes the development of a homogeneous distribution of carbides in the martensitic matrix, with an increase of about 10% in tensile strength and about 7% in elongation to failure. This combination of exceptional strength with a high degree of toughness leads to an improvement in the fatigue behaviour of the steel, which exhibits a higher unnotched and notched fatigue strength (about 15% and 25% respectively) and a lower fatigue notch factor (about 15%) compared to conventionally heat-treated steel. These results highlight that the powder metallurgy tool steel, with the new heat treatment, could be a viable option for the production not only of tools and dies, but also for high-performance automotive components, including even those with complex geometries, such as camshafts or crankshafts.
Metabolomics Study Suggests the Mechanism of Different Types of Tieguanyin (Oolong) Tea in Alleviating Alzheimer’s Disease in APP/PS1 Transgenic Mice
Authors: Tu Youying , Kang Hyunuk , Kim Eunhye , Yang Jiangfan , He Puming , Wu Yuanyuan , Li Bo , Liu Xiaobo , Liu Junsheng
Published: May 2022

Previously, we found that three types of Tieguanyin tea (Tgy-Q, Tgy-N and Tgy-C) extracts could alleviate Alzheimer’s disease (AD) in a mouse model among which Tgy-C was more effective. In this study, APP/PS1 transgenic mice were used to investigate the metabolomic changes in the feces of mice treated with Tieguanyin tea extracts. Results showed that the profile of fecal metabolites was obviously changed in AD mice. Metabolomics analysis found the effects of Tgy-C, especially its decreasing effect on the fecal metabolites in AD mice—132 of the 155 differential metabolites were decreased. KEGG enrichment revealed that differential metabolites could participate in functional pathways including protein digestion and absorption, biosynthesis of amino acids and ABC transporters. Further comparisons of the metabolites between groups showed that although Tgy-N and Tgy-Q exerted a decreasing effect on the fecal metabolites, Tgy-C was more effective. Moreover, correlation analysis found that the levels of the fecal metabolites were highly correlated with the contents of functional components in tea extracts. Finally, 16S rDNA sequencing presented that Tieguanyin extracts modified the gut microbiota by targeting diverse bacteria. In this study, we investigated the differences of three types of Tieguanyin tea extracts on the fecal metabolites as well as the bacterial community of the gut microbiota in AD mice. The identified differential metabolites and the changed intestinal bacteria might provide potential diagnostic biomarkers for the occurrence and progression of AD.
Hole Injection Effect and Dynamic Characteristic Analysis of Normally Off p-GaN HEMT with AlGaN Cap Layer on Low-Resistivity SiC Substrate
Authors: Wang Hsiang-Chun , Liu Chia-Hao , Huang Chong-Rong , Chiu Hsien-Chin , Kao Hsuan-Ling , Liu Xinke
Published: May 2022

A p-GaN HEMT with an AlGaN cap layer was grown on a low resistance SiC substrate. The AlGaN cap layer had a wide band gap which can effectively suppress hole injection and improve gate reliability. In addition, we selected a 0° angle and low resistance SiC substrate which not only substantially reduced the number of lattice dislocation defects caused by the heterogeneous junction but also greatly reduced the overall cost. The device exhibited a favorable gate voltage swing of 18.5 V (@IGS = 1 mA/mm) and an off-state breakdown voltage of 763 V. The device dynamic characteristics and hole injection behavior were analyzed using a pulse measurement system, and Ron was found to increase and VTH to shift under the gate lag effect.
Geological Significance of Late Permian Magmatic Rocks in the Middle Section of the Ailaoshan Orogenic Belt, SW China: Constraints from Petrology, Geochemistry and Geochronology
Authors: Zhang Yaoyao , Liu Kai , Wang Ye , Zhang Da , Mo Xuanxue , Deng Yuefei , Yu Tingxi , Zhao Zenan
Published: May 2022

The Ailaoshan orogenic belt, located in the SE margin of the Qinghai–Tibet Plateau, is an important Paleo-Tethys suture zone in the eastern margin of the Sanjiang Tethys tectonic domain. The areas of Mojiang and Zhenyuan, located in the middle part of the Ailaoshan orogenic belt, are the key parts of the Ailaoshan Paleo-Tethys Ocean closure and collision orogeny. The rhyolites outcropped in the Mojiang area, and the granite porphyries outcropped in Zhenyuan area, are systematically studied for petrology, isotope geochemistry and geochronology. The Zircon U-Pb geochronology of rhyolites and granite porphyries give weighted average ages of 253.4 ± 4.2 Ma and 253.3 ± 2.0 Ma, respectively, both of which were formed in the late Permian period. The rhyolites belong to potassic calc-alkaline to subalkaline series. The patterns of the rare earth elements (REE) show a right-inclined seagull-type distribution, and the trace elements plot is right-inclined. The granite porphyries are high potassic calc-alkaline to subalkaline. The REE patterns show a right-inclined distribution, and the trace elements plot is right-inclined, which is consistent with the typical patterns observed in the crust. The peraluminous, highly differentiated and high ASI values suggest that rhyolites and granite porphyries are S-type granites. The zircon εHf(t) of the rhyolites range from −7.22 to −0.72, and two-stage Hf zircon model ages are (TDMC) 1771–2352 Ma, indicating that the magma source area is mainly crust-derived. The zircon εHf(t) of the granite porphyries range from −0.97 to 4.08, and two-stage Hf zircon model ages are (TDMC) 1336–1795 Ma, indicating that the magma is derived from a depleted mantle source and the partial melting of ancient crustal materials. The rhyolites and granite porphyries were possibly formed in the syn-collisional tectonic setting during the late Permian, and their ages limited the time of the final closure of the Ailaoshan Ocean and the initiation of collisional orogeny.
Geophysical Implications for Prospective Prediction of Copper Polymetallic Ore Bodies: Northern Margin of Alxa Block, China
Authors: Meng Yinsheng , Chen Xiaoqiang , Wang Wenguo , Li Ruihong , Wang Gang
Published: May 2022

The Alxa Block is located in the middle part of the Central Asian orogenic belt, which is the coupling belt of the North China, Tarim, and Kazakhstan Plates. The east–west-trending deep faults control stratigraphic distribution and magmatic activity in the region. To detect the EW-trending ore-controlling deep structures, a 440 km NS section of magnetotelluric sounding was conducted from Minle to Ejinaqi. The phase tensor and electrical principal axis were analyzed based on the measured data to build the exploration model. The electrical structure model along the section was obtained using nonlinear conjugate gradient (NLCG) 2D inversion. Combined with the geological, geophysical, and deposit distribution characteristics in the area, the comprehensive study of magnetotelluric sounding profile shows that the resistivity presents as zoned along the profile. The Engelwusu ophiolite mélange belt is stacked in clumps with high and low resistivity, indicating that the northern margin of the Engelwusu Belt subducts below the high-resistivity zone, representing the passive continental margin. The southern end of the Engelwusu ophiolite belt is primarily the prospecting potential area for copper–gold deposits, whereas the northern end of the Engelwusu ophiolite belt corresponds to copper polymetallic deposits.