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Effect of Build Direction on Fatigue Performance of L-PBF 316L Stainless Steel

Acta Metallurgica Sinica(English Letters) 2020年第4期33卷 539-550页

作者： Chenfan Yu Yuan Zhong Peng Zhang Zhenjun Zhang Congcong Zhao Zhefeng Zhang Zhijian Shen Wei Liu State Key Laboratory of New Ceramic and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Department of Materials and Environmental Chemistry Arrhenius LaboratoryStockholm University10691 StockholmSweden Laboratory of Fatigue and Fracture for Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

The microstructure and fatigue and tensile properties of 316 L stainless steel fabricated via laser powder bed fusion(L-PBF)were *** 316 L stainless steel specimens with different loading directions which are either perpendicular to or parallel to building direction were prepared by L-PBF *** results of X-ray diffraction tomography showed that there was no significant difference in morphology and size/distribution of the defects in the HB and VB *** long axis of columnar grains is generally parallel to the build direction,the fatigue crack encounters more grain boundaries in VB samples under cyclic loading,which led to enhanced fatigue resistance of VB samples compared with HB *** contrast to HB sample,the VB sample has a higher fatigue strength due to a higher resistance to localized plastic deformation under cyclic *** differences in fatigue properties of L-PBF 316 L SS with different build directions were predominantly controlled by solidification microstructures.

关键词： Austenitic stainless steel Laser powder bed fusion Tensile properties Fatigue strength

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Gallium Oxide as Photonic Integrated Platforms in the UV-Visible Spectra

Gallium Oxide as Photonic Integrated Platforms in the UV-Vis...

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2023 Conference on Lasers and Electro-Optics, CLEO 2023

作者： Zhou, Jingan Zhao, Xuan Xu, Rui Zhang, Xiang Fu, Kai Li, Tao Xu, Mingfei Luo, Shisong He, Ziyi Robinson, Jacob T. Zhu, Hanyu Ajayan, Pulickel M. Zhang, Xiaodong Zhao, Yuji Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States School of Electrical Computer and Energy Engineering Arizona State University TempeAZ85287 United States Nanofabrication facility Suzhou Institute of Nano-Tech and Nano-Bionics Chinese Academy of Sciences Jiangsu Suzhou215123 China

We report the Ga2O3 as photonic integrated platforms and its nonlinear optical effects in the UV-visible spectra. A low propagation loss of 3.7 dB/cm and second-order susceptibility of x(2)=4.89xl03pm/V were obtained.... 详细信息

ISBN: (纸本)9781957171258

关键词： Gallium compounds

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Real-Time In Situ Spectroscopic and Electrochemical Analysis of Ion-Water-Polymer Interactions at Functionalized PEDOT Interfaces

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Analytical chemistry 2025年第22期97卷 2025 May 25页

作者： Chia-Hsin Lin Ya-Chen Gong Hsuan-Yu Chen Heng-Liang Wu Shyh-Chyang Luo Department of Materials Science and Engineering National Taiwan University No. 1 Sec. 4 Roosevelt Road Taipei 10617 Taiwan. Center for Condensed Matter Sciences and Center of Atomic Initiative for New Materials National Taiwan University No. 1 Sec. 4 Roosevelt Road Taipei 10617 Taiwan. International Graduate Program of Molecular Science and Technology National Taiwan University Taipei 10617 Taiwan.

Understanding water dynamics at material interfaces is crucial for applications in biotechnology, electrochemistry, and energy systems. In this study, we employed Fourier transform infrared spectroscopy and electrochemical quartz crystal microbalance with dissipation monitoring to investigate the hydration states and ion interactions of functionalized poly(3,4-ethylenedioxythiophene) (PEDOT) films. By applying controlled potentials, we monitored ion absorption and desorption while using Gaussian fitting to analyze the O-H stretching bands. Our results revealed that sulfate ions (SO) compete with water molecules at PEDOT interfaces with hydroxyl groups, whereas perchlorate ions (ClO) exhibit minimal interference due to their weak water interactions. For PEDOT functionalized with zwitterionic phosphorylcholine groups, higher levels of intermediate water and nonfreezing water mitigated dehydration in saline environments. This work highlights the synergy between electrochemical and spectroscopic methods for real-time analysis of ion-water-polymer interactions, providing critical insights into interfacial phenomena regulated by applied potential.

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Tissue-engineered vascular grafts for cardiovascular disease management: Current strategies, challenges, and future perspectives

MedComm - Biomaterials and Applications

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MedComm - Biomaterials and Applications 2024年第3期3卷

作者： Das, Kuntal Kumar Mishra Tiwari, Ruchi Shankar, Om Maiti, Pralay Dubey, Ashutosh Kumar Bioelectronics Laboratory Department of Ceramic Engineering Indian Institute of Technology (BHU) Symbiosis Centre for Stem Cell Research (SCSCR) Symbiosis International University (SIU) Department of Cardiology Institute of Medical Sciences Banaras Hindu University School of Materials Science and Technology Indian Institute of Technology (BHU)

Cardiovascular diseases are the leading cause of mortality which primarily occurs due to the blood vessel obstruction or narrowing. Surgical procedures such as, coronary artery and peripheral artery bypass grafting frequently require vascular grafts for long-term revascularization. However, using autogenous vessels, such as the internal thoracic artery and saphenous vein, especially for vessels with diameters less than 6 mm, are associated with number of concerns due to limited availability, invasive retrieval procedures, and aptness. To overcome these limitations, the development of tissue-engineered vascular grafts (TEVGs) is in continuous thrust. This review comprehensively provides the potentiality of a range of artificial and naturally occurring biopolymers and their fabrication techniques, cell sources and seeding techniques to realize the state-of-the-art TEVGs. Moreover, this review article presents a synopsis of insights obtained from a variety of in vitro and in vivo studies, including human clinical trials. It underscores the need for further exploration into key areas such as optimal cell sources, seeding techniques, mechanical properties, hemodynamics, graft integration, the impact of patient conditions, optimum burst pressure, sufficient suture strength, hydrophilicity, biodegradability, and related factors. In summary, the review offers insights into the current strategies, challenges, and future perspectives of TEVG. © 2024 The Author(s). MedComm – Biomaterials and Applications published by John Wiley & Sons Australia, Ltd on behalf of Sichuan International Medical Exchange & Promotion Association (SCIMEA).

关键词： biomaterials biopolymers cardiovascular diseases tissue-engineered vascular grafts (TEVGs) vascular tissue engineering (VTE)

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Exploring the electronic properties of shallow donor impurities in modified ∩-shaped potential: effects of applied electric field, parabolicity, compositions, and thickness

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The European Physical Journal B 2023年第6期96卷 1-12页

作者： En-nadir, Redouane El Ghazi, Haddou Tihtih, Mohammed Zaki, Shrouk E. Belaid, Walid Maouhoubi, Ibrahim Zorkani, Izeddine Faculty of Sciences University of Sidi Mohamed Ben Abdullah Fez Morocco ENSAM University Hassan-II University Casablanca Morocco Institute of Ceramic and Polymer Engineering University of Miskolc Miskolc Hungary Department of Physics Faculty of Science Sélçuk University Konya Turkey Department of Nanotechnology and Advanced Materials Sélçuk University Konya Turkey

In this paper, we employed numerical modeling to investigate the influence of crucial parameters, namely electric field, confinement parabolicity, compositions, and structure parameters, on the electron probability, impurity polarizability, diamagnetic susceptibility, and ionization energy of hydrogenic donor impurities within a modified ∩-shaped potential. The Schrödinger equation is solved using the finite element approach within the framework of the effective mass theory to analyze the resulting electronic properties. Our results demonstrate a significant impact of these factors on both electrons and impurities, with the ability to fine-tune these properties through parameter adjustments. These findings hold significant implications for the advancement of precise and efficient III-nitride-based optoelectronic devices, including solar cells, photodetectors, and lasers.

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Potential of caffeic acid as an effective natural antioxidant for polypropylene-polyethylene copolymers: A DFT and experimental study

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Current Research in Green and Sustainable Chemistry 2024年 9卷

作者： Hernández Fernández, Joaquín Alejandro Ortiz Paternina, Katherine Liset López Martínez, Juan Chemistry Program Department of Natural and Exact Sciences University of Cartagena Chemical Engineering Program School of Engineering Universidad Tecnológica de Bolivar Parque Industrial y Tecnológico Carlos Velez Pombo Department of Natural and Exact Science Universidad de la Costa Polytechnical University of Valencia (UPV) Institute of Materials Technology (ITM)

Caffeic acid (CAF) i is a polyphenolic compound commonly found in plants, valued for its ability to act as an antioxidant. This study focused on investigating the impact of a natural antioxidant, specifically caffeic acid (CAF), compared to two synthetic antioxidants, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), on the thermal stability of propylene/ethylene copolymer (C-PP/PE), Aiming to establish a theoretical framework for the advancement of novel polymeric antioxidant compounds. Theoretical calculations were conducted to determine each compound's thermodynamic properties and antioxidant activity. The phenolic hydroxyl bond dissociation enthalpy (BDE) values revealed that BHA had the lowest value (325.6 kJ mol⁻¹), trailed by CAF (328.2 kJ mol⁻¹) and BHT (341.3 kJ mol⁻¹), indicating a higher electron-donating capacity of BHA. Transition energy (TS) calculations indicated that BHA had the lowest TS energy (49.29 kJ mol⁻¹), succeeded by CAF (57.61 kJ mol⁻¹) and then BHT (75.57 kJ mol⁻¹), suggesting greater efficiency in radical scavenging. Additionally, the obtained rate constants showed that CAF had the highest hydrogen abstraction rate (k = 1.05 × 10⁵ M⁻¹ s⁻¹), followed by BHA (k = 1.17 × 10⁴ M⁻¹ s⁻¹), and then BHT (k = 4.2 × 10³ M⁻¹ s⁻¹). These results support the effectiveness of CAF as a potentially more active antioxidant. In the experimental part of this study, it was observed that C-PP/PE with BHA showed a lower melt flow index (MFI) (8.51), indicating more excellent thermal stability. On the other hand, samples containing natural caffeic acid extracts exhibited a gradual decrease in MFI with increasing CAF concentration (MFI of 9.4, 8.82, 7.59, 6.44, and 5.98 for concentrations of 0.025, 0.05, 0.075, 0.1, and 0.125 ppm, respectively), suggesting a progressive improvement in the thermal stability of C-PP/PE

关键词： Activation energy Antioxidant Bond dissociation energy Caffeic acid MFI Stability

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Biodegradable Pbat/Pla Blend Films Incorporated with Turmeric and Cinnamomum Powder: A Potential Alternative for Active Food Packaging

SSRN

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SSRN 2023年

作者： de Castro, Layara L.R.L. Abreu, Iago R. Braz, Cristiano J.F. Rodrigues, Samara C.S. dos Araújo, Regilda S.R.M. Folkersma, Rudy de Carvalho, Laura H. Barbosa, Renata Alves, Tatianny S. Graduate Program in Materials Science and Engineering Federal University of Piauí Teresina64.049-550 Brazil Department of Physics Federal Institute of Education Science and Technology of Piauí Teresina Central Campus Teresina64.000-040 Brazil Department of Nutrition Federal University of Piauí Teresina64.049-550 Brazil NHL Stenden University of Applied Sciences Groningen9727 Netherlands Graduate Program in Materials Science and Engineering Federal University of Campina Grande PI TeresinaCEP: 58.100-000 Brazil

Active packaging made from biodegradable polymers and natural additives appears as an ecological alternative. In addition to having antioxidant activity and enhancing food preservation, it allows mitigating the negative impacts caused by improper disposal. This study pursued to produce biodegradable films based on a polymer blend PBAT/PLA (Ecovio®) using the flat extrusion method. The films were prepared with the incorporation of 5 wt% of powdered turmeric or cinnamon as natural additives. The films obtained, and those reprocessed twice, were characterized in terms of colorimetric, UV light transmittance, water contact angle, water vapor permeability, morphology, mechanical properties, and antioxidant activity. Cinnamon reduced the UV light transmittance and made a surface more hydrophobic. Reprocessing led to greater elongation and maximum load, associated with increased dispersion and distribution, as evidenced in the morphological analysis. The films developed have significant potential for applications in active food packaging, with emphasis on cinnamon-additivated films. © 2023, The Authors. All rights reserved.

关键词： Biodegradable polymers

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Electronic and Optical Excitations in van der Waals materials from a Non-Empirical Wannier-Localized Optimally-Tuned Screened Range-Separated Hybrid Functional

arXiv

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arXiv 2024年

作者： Camarasa-Gómez, María Gant, Stephen E. Ohad, Guy Neaton, Jeffrey B. Ramasubramaniam, Ashwin Kronik, Leeor Department of Molecular Chemistry and Materials Science Weizmann Institute of Science Rehovoth7610001 Israel Department of Physics University of California BerkeleyCA94720 United States Materials Sciences Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Kavli Energy NanoSciences Institute at Berkeley University of California BerkeleyCA94720 United States Department of Mechanical and Industrial Engineering University of Massachusetts Amherst AmherstMA01003 United States Materials Science and Engineering Graduate Program University of Massachusetts AmherstMA01003 United States

Accurate prediction of electronic and optical excitations in van der Waals (vdW) materials is a long-standing challenge for density functional theory. The recently proposed Wannier-localized optimally-tuned screened range-separated hybrid (WOT-SRSH) functional has proven successful in non-empirical determination of electronic band gaps and optical absorption spectra for various covalent and ionic crystals. However, for vdW materials the tuning of the material- and structure-dependent functional parameters has, until now, only been attained semi-empirically. Here, we present a non-empirical WOT-SRSH approach applicable to vdW materials, with the optimal functional parameters transferable between monolayer and bulk. We apply this methodology to prototypical vdW materials: black phosphrous, moldybdenum disulfide, and hexagonal boron nitride (in the latter case including zero-point renormalization). We show that the WOT-SRSH approach consistently achieves accuracy levels comparable to experiments and ab initio many-body perturbation theory (MBPT) calculations for band structures and optical absorption spectra, both on its own and as an optimal starting point for MBPT calculations. Copyright © 2024, The Authors. All rights reserved.

关键词： Energy gap

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Optical library of Ga2O3 polymorphs

arXiv

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arXiv 2024年

作者： Galeckas, Augustinas Cernescu, Adrian Kaźmierczak-Balata, Anna García-Fernández, Javier Bazioti, Calliope Azarov, Alexander Park, Ji-Hyeon Jeon, Dae-Woo Lee, Halin Lee, Won-Jae Zhu, Rui Mei, Zengxia Prytz, Øystein Kuznetsov, Andrej Department of Physics Centre for Materials Science and Nanotechnology University of Oslo PO Box 1048 Blindern OsloN-0316 Norway attocube systems AG Haar85540 Germany Institute of Physics Silesian University of Technology Gliwice44-100 Poland Korea Institute of Ceramic Engineering & Technology Jinju52851 Korea Republic of Department of Advanced Materials Engineering Dong-Eui University Busan47340 Korea Republic of Songshan Lake Materials Laboratory Guangdong Dongguan523808 China Institute of Physics Chinese Academy of Sciences Beijing100190 China

Gallium oxide is a novel advanced material gaining increasing attention for its unique combination of functional properties. It forms in several phases or polymorphs—α, β, γ, and κ—having variable properties because of different lattice symmetries. Optical properties are of particular importance as they determine specific device applications and can also be used for phase identification. However, a direct comparison of optical polymorph signatures, including such critical parameters as bandgaps, is challenging due to the scattered, limited, or even absent data for certain phases in the literature. To address this issue, in the present work we systematically cross-correlate optical emission and absorption features of α, β, γ, and κ thin films, as well as differently oriented β-phase bulk crystals and γ/β double polymorph structures. We demonstrate that the optical bandgap and emission features scale consistently across these polymorphs upon minimization of the methodological uncertainties. As a result, this work provides a comparative library of near- and far-field optical signatures of the polymorphs for use by the multidisciplinary research community working with gallium oxide. © 2024, CC BY-NC-ND.

关键词： Polymorphism

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Microstructural Effect on the Corrosion Behavior of N- and P-Type Bismuth Tellurides Fabricated by Induction Melting

SSRN

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SSRN 2023年

作者： El-Makaty, Farah M. Nawaz, Muddasir Shakoor, R. Abdul Hammuda, Abdelmagid Youssef, Khaled M. Mechanical and Industrial Engineering Department Qatar University Doha2713 Qatar Qatar University Doha2713 Qatar Materials Science and Technology Graduate Program College of Arts and Sciences Qatar University Doha2713 Qatar

Numerous efforts have been made to understand and enhance the thermoelectric properties of bismuth telluride alloys. However, limited studies have been reported to investigate the corrosion behavior of these alloys and their suitability for industrial applications. This paper examines the corrosion behavior of three different bismuth telluride alloys prepared by induction melting: pristine Bi2Te3, n-type Bi2Te2.55Se0.45, and p-type Bi0.6Sb1.4Te3. The electrochemical response of the samples is tested in 3.5 wt.% NaCl solution at room temperature. Potentiodynamic polarization curves (Tafel plots) revealed that the n-type sample formed a passive layer compared to the pristine and the p-type samples, which showed pitting corrosion. The different trends observed in the samples were related to their evolved microstructures, where fingerprint-like features in the pristine and the p-type samples showed high susceptibility to pitting corrosion. In contrast, a unique needle-like microstructure of the n-type samples acted as nucleation sites for passive layer formation causing higher corrosion resistance in this sample. © 2023, The Authors. All rights reserved.

关键词： Microstructure

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