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Effect of TiO 2 concentration in PVDF-TiO 2 -PVP mixed matrix membrane performance using ultrafiltration process

materials Today: Proceedings 2024年 96卷 1-5页

作者： Rianyza Gayatri Erna Yuliwati Ahmad Noor Syimir Fizal Muhamad Zulhilmi Zailani Juhana Jaafar Muzafar Zulkifli Wirach Taweepreda Ahmad Naim Ahmad Yahaya Universiti Kuala Lumpur Malaysian Institute of Chemical and Bioengineering Technology Alor Gajah Melaka 78000 Malaysia Department of Material Science and Technology Faculty of Science Prince of Songkla University (PSU) Hat Yai Songkla 90110 Thailand Program Study of Chemical Engineering Faculty of Engineering Universitas Muhammadiyah Palembang Jalan A.Yani 13 Ulu Kota Palembang 30263 Indonesia Centre for Sustainability of Ecosystem & Earth Resources (Pusat ALAM) Universiti Malaysia Pahang Lebuh Persiaran Tun Khalil Yaakob 26300 Gambang Pahang Malaysia Advanced Membrane Technology Research Centre (AMTEC) Faculty of Chemical and Energy Engineering Universiti Teknologi

This study investigated how the addition of hydrophilic TiO 2 to a porous asymmetric polyvinylidene fluoride (PVDF) Ultrafiltration (UF) membrane altered its properties and performance. The hydrophilicity and flux of PVDF and polyvinylpyrrolidone (PVP) combinations will be lower, and TiO 2 will significantly impact raising those values. By mixing titanium dioxide (TiO 2 ) nanoparticles with a pore-forming agent in a dope solution, PVDF-TiO 2 -PVP membranes were prepared via non-solvent-induced phase inversion method. Experiments using PVDF membranes with varying concentrations of TiO 2 (0, 0.25, 0.5, 1, 1.5, and 2% wt) were applied to evaluate pure water flux and Bovine Serum Albumin (BSA) flux. The functional group composition of membranes was investigated by Fourier transform infrared spectroscopy. The wettability of porous membranes was determined by measuring contact angles. Results demonstrated that membranes constructed from PVDF/PVP/TiO 2 with a lower loading of TiO 2 nanoparticles had a smaller mean pore size, more apertures inside the membrane, and better membrane hydrophilicity. The highest flux of pure water (121 L/m 2 h) was achieved by the PVDF-TiO 2 -PVP mixed-matrix membrane at a TiO 2 concentration of 2 wt%.

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Quantum oscillation studies of the nodal line semimetal Ni3In2S2-xSex

arXiv

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arXiv 2025年

作者： Sharma, M.M. Chhetri, Santosh Karki Acharya, Gokul Graf, David Upreti, Dinesh Dahal, Sagar Un Nabi, Md Rafique Rahman, Sumaya Sakon, Josh Churchill, Hugh O.H. Hu, Jin Department of Physics University of Arkansas FayettevilleAR72701 United States National High Magnetic Field Lab TallahasseeFL32310 United States MonArk NSF Quantum Foundry University of Arkansas FayettevilleAR72701 United States Material Science and Engineering Program Institute for Nanoscience and Engineering University of Arkansas FayettevilleAR72701 United States Department of Chemistry & Biochemistry University of Arkansas FayettevilleAR72701 United States

Ternary shandite compounds with the general formula T3M2X2 (T = Ni, Co, Rh or Pd;M = Sn, In, or Pb;and X = S or Se) have emerged as a large pool of topological semimetals. This family of compounds hosts different topological phases for various combinations of T, M and X. This paper reports the observation of quantum oscillations under the high magnetic fields in Ni3In2S2-xSex single crystals. Angular dependence of oscillation frequency suggests an evolution of the Fermi surface from three-dimensional to two-dimensional on Se substitution for S in Ni3In2S2. The effective mass obtained for each composition by fitting the oscillation amplitude with the Lifshitz-Kosevich formula, shows no significant change, suggesting that the topological phase might be relatively robust against enhanced SOC upon Se doping in Ni3In2S2 Copyright © 2025, The Authors. All rights reserved.

关键词： Single crystals

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Imaging 3D Chemistry at 1 nm Resolution with Fused Multi-Modal Electron Tomography

arXiv

引用

arXiv 2023年

作者： Schwartz, Jonathan Di, Zichao Wendy Jiang, Yi Manassa, Jason Pietryga, Jacob Qian, Yiwen Cho, Min Gee Rowell, Jonathan L. Zheng, Huihuo Robinson, Richard D. Gu, Junsi Kirilin, Alexey Rozeveld, Steve Ercius, Peter Fessler, Jeffrey A. Xu, Ting Scott, Mary Hovden, Robert Department of Materials Science and Engineering University of Michigan Ann ArborMI United States Mathematics and Computer Science Division Argonne National Laboratory LemontIL United States Advanced Photon Source Facility Argonne National Laboratory LemontIL United States Department of Material Science and Engineering Northwestern University EvanstonIL United States Department of Materials Science and Engineering University of California at Berkeley BerkeleyCA United States Department of Chemistry and Chemical Biology Cornell University IthacaNY United States Argonne Leadership Computing Facility Argonne National Laboratory LemontIL United States Department of Material Science and Engineering Cornell University IthacaNY United States Kavli Institute at Cornell for Nanoscale Science Cornell University IthacaNY United States Dow Chemical Co. MidlandMI United States National Center for Electron Microscopy Molecular Foundry Lawrence Berkeley National Laboratory BerkeleyCA United States Department of Electrical Engineering and Computer Science University of Michigan Ann ArborMI United States Materials Science Division Lawrence Berkeley National Laboratory BerkeleyCA United States Applied Physics Program University of Michigan Ann ArborMI United States

Measuring the three-dimensional (3D) distribution of chemistry in nanoscale matter is a longstanding challenge for metrological science. The inelastic scattering events required for 3D chemical imaging are too rare, requiring high beam exposure that destroys the specimen before an experiment completes. Even larger doses are required to achieve high resolution. Thus, chemical mapping in 3D has been unachievable except at lower resolution with the most radiation-hard materials. Here, high-resolution 3D chemical imaging is achieved near or below one nanometer resolution in a Au-Fe3O4 metamaterial, Co3O4 - Mn3O4 core-shell nanocrystals, and ZnS-Cu0.64S0.36 nanomaterial using fused multi-modal electron tomography. Multi-modal data fusion enables high-resolution chemical tomography often with 99% less dose by linking information encoded within both elastic (HAADF) and inelastic (EDX / EELS) signals. Now sub-nanometer 3D resolution of chemistry is measurable for a broad class of geometrically and compositionally complex materials. © 2023, CC BY.

关键词： Zinc sulfide

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Pressure-driven homogenization of lithium disilicate glasses

arXiv

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arXiv 2023年

作者： Bakhouch, Yasser Buchner, Silvio Silveira, Rafael Abel Resende, Leonardo Pereira, Altair Soria Hasnaoui, Abdellatif Atila, Achraf LS2ME Faculté Polydisciplinaire Khouribga Sultan Moulay Slimane University of Beni Mellal B.P 145 Khouribga25000 Morocco Graduate Program in Materials Science Federal University of Rio Grande do Sul Porto Alegre Brazil Department of Material Science and Engineering Saarland University Saarbrücken66123 Germany

Lithium disilicate glasses and glass-ceramics are good potential candidates for biomedical applications and solid-state batteries, and serve as models of nucleation and crystal growth. Moreover, these glasses exhibit a phase separation that influences their nucleation and crystallization behavior. The atomistic mechanisms of the phase separation and their pressure dependence are unclear so far. Here, we used molecular dynamics simulations supported by experiments to assess the spatial heterogeneity of lithium disilicate glasses prepared under pressure. We show that the glass heterogeneity decreases with increasing the cooling pressure and almost disappears at pressures around 30 GPa. The origin of the heterogeneity is due to the attraction between Li cations to form clustering channels, which decreases with pressure. Through our results, we hope to provide valuable insights and guidance for making glass-ceramics with controlled crystallization. Copyright © 2023, The Authors. All rights reserved.

关键词： Phase separation

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Subdiffusive wave transport and weak localization transition in three-dimensional stealthy hyperuniform disordered systems

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Physical Review B 2022年第6期105卷 064204-064204页

作者： F. Sgrignuoli S. Torquato L. Dal Negro Department of Electrical and Computer Engineering & Photonics Center Boston University 8 Saint Mary's Street Boston Massachusetts 02215 USA Department of Chemistry Department of Physics Princeton Institute for the Science and Technology of Materials and Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08540 USA Division of Material Science and Engineering Boston University 15 Saint Mary's Street Brookline Massachusetts 02446 USA Department of Physics Boston University 590 Commonwealth Avenue Boston Massachusetts 02215 USA

The purpose of this work is to understand the fundamental connection between structural correlations and light localization in three-dimensional (3D) open scattering systems of finite size. We numerically investigate the transport of vector electromagnetic waves scattered by resonant electric dipoles spatially arranged in 3D space by stealthy hyperuniform disordered point patterns. Three-dimensional stealthy hyperuniform disordered systems are engineered with different structural correlation properties determined by their degree of stealthiness χ. Such fine control of exotic states of amorphous matter enables the systematic design of optical media that interpolate in a tunable fashion between uncorrelated random structures and crystalline materials. By solving the electromagnetic multiple scattering problem using Green's matrix spectral method, we establish a transport phase diagram that demonstrates a distinctive transition from a diffusive to a weak localization regime beyond a critical scattering density that depends on χ. The transition is characterized by studying the Thouless number and the spectral statistics of the scattering resonances. In particular, by tuning the χ parameter, we demonstrate large spectral gaps and suppressed subradiant proximity resonances, facilitating light localization. Moreover, consistently with previous studies, our results show a region of the transport phase diagram where the investigated scattering systems become transparent. Our work provides a systematic description of the transport and weak localization properties of light in stealthy hyperuniform structures and motivates the engineering of photonic systems with enhanced light-matter interactions for applications to both classical and quantum devices.

关键词： Anderson localization Light-matter interaction Mesoscopics Photonics Scattering theory Weak localization Metamaterials

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Effects of numbers of wells on optical properties of periodic InGaN graded structure

Effects of numbers of wells on optical properties of periodi...

引用

Low-Dimensional materials and Devices 2021

作者： Sarollahi, Mirsaeid Allaparthi, Rohith Alhelais, Reem Aldawsari, Manal A. Refaei, Malak A. Maruf, Md Helal Uddin Ware, Morgan E. University of Arkansas Electrical Engineering Department 3217 Bell Engineering Center FayettevilleAR72701 United States University of Arkansas Microelectronics-Photonics Program 731 West Dickson Street FayettevilleAR72701 United States University of Arkansas Material Science and Engineering 731 West Dickson Street FayettevilleAR72701 United States Institute for Nanoscience and Engineering FayettevilleAR72701 United States

ISBN: (数字)9781510644397

ISBN: (纸本)9781510644380

The optical properties of periodic graded GaN/InGaN are studied. We have designed graded InGaN quantum well (QW) structures with the indium composition increasing then decreasing in a zigzag pattern. Through polarization doping, this naturally creates alternating p-type and n-type regions. Separate structures are designed by varying the number of repeating periods (1 to 3), while maintaining constant overall structure thicknesses. Calculation of the transition probabilities and the electron and hole wave-functions between the conduction band and the valence band reveals a complex energy structure which predicts the photoluminescence peaks for band to band transitions. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

关键词： Optical properties

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Frustrated metastable-to-equilibrium grain boundary structural transition in NbMoTaW due to segregation and chemical complexity

arXiv

引用

arXiv 2023年

作者： Geiger, Ian Apelian, Diran Pan, Xiaoqing Cao, Penghui Luo, Jian Rupert, Timothy J. Material and Manufacturing Technology University of California IrvineCA92697 United States Department of Materials Science and Engineering University of California IrvineCA92697 United States Department of Physics and Astronomy University of California IrvineCA92697 United States Department of Mechanical and Aerospace Engineering University of California IrvineCA92697 United States Department of NanoEngineering University of California San Diego La Jolla CA92093 United States Program in Materials Science and Engineering University of California San Diego La Jolla CA92093 United States

Grain boundary structural transitions can lead to significant changes in the properties and performance of materials. In multi-principal element alloys, understanding these transitions becomes complex due to phenomena such as local chemical ordering and multi-component segregation. Using atomistic simulations, we explore a metastable-to-equilibrium grain boundary structural transition in NbMoTaW. The transition, characterized by structural disordering and reduced free volume, shows high sensitivity to its local chemical environment. Most notably, the transition temperature range of the alloy is more than twice that of a pure metal. Differences in composition between coexisting metastable and equilibrium structures highlight the change in local site availability due to structural relaxation. Further examination of grain boundaries with fixed chemical states at varying temperatures reveals that the amount of segregation significantly influences the onset temperature yet has minimal effect on the transition width. These insights underscore the profound effect of chemical complexity and ordering on grain boundary transitions in complex concentrated alloys, marking a meaningful advancement in our understanding of grain boundary behavior at the atomic level. Copyright © 2023, The Authors. All rights reserved.

关键词： Grain boundaries

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Effect of Surface Activation on the Corrosion Resistance of a MAO/Ni-P Composite Coating on LZ91 Magnesium Alloy

引用

Journal of the Taiwan Institute of Chemical Engineers 2023年第1期147卷

作者： Chen, Chi-An Lee, Jeou-Long Jian, Shun-Yi Lee, Chia-Yu Ger, Ming-Der Combination Medical Device Technology Division Medical Devices R&D Service Department Metal Industries Research & Development Centre Kaohsiung802 Taiwan Department of Chemical and Materials Engineering Lung Hwa University of Science and Technology Taoyuan330 Taiwan Department of Material Engineering Ming Chi University of Technology New Taipei City Taiwan Center for Plasma and Thin Film Technologies Ming Chi University of Technology New Taipei Taiwan Graduate School of Defense Science Chung Cheng Institute of Technology National Defense University Taoyuan Taiwan Department of Chemical & Materials Engineering Chung Cheng Institute of Technology National Defense University Taoyuan Taiwan System Engineering and Technology Program National Chiao Tung University Hsin-Chu Taiwan

Background: LZ91 Magnesium alloy with a dual-phase structure has improved mechanical properties and a low density of about 1.48 g/cm3 but their limited resistance to corrosion limits their application. Therefore, it is a great challenge to increase the stability of LZ91 alloys under corrosive factors and environments. Methods: This study uses micro-arc oxidation (MAO) and an electroless nickel-phosphorus (Ni-P) plated composite film to increase the corrosion resistance of LZ91 magnesium alloy. Before electroless Ni-P plating, the MAO layers are activated by palladium catalysts at different pH values to produce composite coatings. SEM, EDS and Image J are used to determine the surface properties and elemental composition of the samples. The corrosion resistance is measured using a potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS) in 3.5 wt.% NaCl solution. Findings: The results show that the MAO coating is activated by an acid catalyst and the surface is obviously corroded. The electroless Ni-P plating grows into the MAO coating and the substrate corrodes. Therefore, corrosive medium (chloride ion) easily enter to the substrate and pitting corrosion occurred. On the contrary, activation by a neutral catalyst (pH=7) maintains the original structure of the MAO coating and provides a good bonding interface for the Ni-P coating. Form the potentiodynamic analysis can be finds that the corrosion potential for the neutral catalyst treated sample is -0.35V and the corrosion current density value is 1.77×10−6 A/cm2, so the corrosion characteristic become better than the acid catalyst treated samples. In terms of the long-term resistance after 48 h, EIS analysis shows that the resistance value remains at about 7.6×104 Ω•cm2. A composite coating that is compact and with excellent resistance to corrosion resistance is produced, which provides better protection for LZ91 magnesium alloys. © 2023 Taiwan Institute of Chemical Engineers

关键词： Corrosion resistance

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Dynamic twisting and imaging of moiré crystals

arXiv

引用

arXiv 2023年

作者： Zhang, Qixuan Senaha, Trevor Zhang, Ruolun Wu, Chen Lyu, Lingyuan Cao, Leonard W. Tresback, Jason Dai, Andrew Watanabe, Kenji Taniguchi, Takashi Allen, Monica T. Program in Material Science and Engineering University of California San DiegoCA92093 United States Department of Physics University of California San DiegoCA92093 United States Center for Nanoscale Systems Harvard University CambridgeMA02138 United States National Institute for Materials Science Namiki 1-1 Ibaraki Tsukuba305-0044 Japan

The electronic band structure is an intrinsic property of solid-state materials that is intimately connected to the crystalline arrangement of atoms. Moiré crystals, which emerge in twisted stacks of atomic layers, feature a band structure that can be continuously tuned by changing the twist angle between adjacent layers [1–4]. This class of artificial materials blends the discrete nature of the moiré superlattice with intrinsic symmetries of the constituent materials, providing a versatile platform for investigation of correlated phenomena whose origins are rooted in the geometry of the superlattice, from insulating states at "magic angles" [5–8] to flat bands in quasicrystals [9]. Here we present a route to mechanically tune the twist angle of individual atomic layers with a precision of a fraction of a degree inside a scanning probe microscope, which enables continuous control of the electronic band structure in situ. Using nanostructured rotor devices, we achieve the collective rotation of a single layer of atoms with minimal deformation of the crystalline lattice. In twisted bilayer graphene, we demonstrate nanoscale control of the moiré superlattice periodicity via external rotations, as revealed using piezoresponse force microscopy [10]. We also extend this methodology to create twistable boron nitride devices, which could enable dynamic control of the domain structure of moiré ferroelectrics [11–13]. This approach provides a route for real-time manipulation of moiré materials, allowing for systematic exploration of the phase diagrams at multiple twist angles in a single device. © 2023, CC BY.

关键词： Atoms

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Depth-Dependent Photoluminescence Characteristic of Gesn/Sigesn Multi-Quantum Wells

SSRN

引用

SSRN 2022年

作者： Ojo, Solomon Stanchu, Hryhorii Acharya, Sudip Said, Abdulla Amoah, Sylvester Benamara, Mourad Li, Chen de Oliveira, Fernando M. Mazur, Yuriy I. Yu, Shui-Qing Salamo, Gregory J. Department of Electrical Engineering University of Arkansas FayettevilleAR72701 United States Material Science and Engineering Program University of Arkansas FayettevilleAR72701 United States Institute for Nanoscience and Engineering University of Arkansas FayettevilleAR72701 United States Department of Physics University of Arkansas FayettevilleAR72701 United States

Multi quantum wells (MQWs) structures based on (Si)GeSn hold promise for near- and mid-infrared light emission and photodetection applications on the Si platform. An MQW consisting of four GeSn/SiGeSn repetitions is grown by chemical vapor deposition (CVD) on Ge/Si(001) virtual substrate to study the interface quality and its effect on optical properties. Intermixing at GeSn/SiGeSn interfaces is found by secondary ion mass spectrometry, which is notably stronger at larger depths. The depth-dependent photoluminescence (PL) characteristic of the MQWs was performed by utilizing different excitation wavelengths and by tailoring the MQW thickness using H2O2-based etching. The results clearly indicate that PL emission is relatively weaker for the QWs with stronger intermixing. © 2022, The Authors. All rights reserved.

关键词： Chemical vapor deposition

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