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Fabrication and photocatalytic activity of TiO2 composite membranes via simultaneous electrospinning and electrospraying process

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Journal of Environmental sciences 2018年第10期30卷 13-24页

作者： Taddao Pahasup-anan Kowit Suwannahong Wipada Dechapanya Ratthapol Rangkupan International Program in Hazardous Substance and Environmental Management Graduate School Chulalongkorn UniversityBangkok 10330Thailand Center of Excellence on Hazardous Substance Management (HSM) Bangkok 10330 Thailand Department of Public Health Faculty of Public Health Western UniversityKanchanaburi 71170 Thailand Department of Chemical Engineering Faculty of Engineering Ubonratchathani UniversityUbonratchathani 34190 Thailand Metallurgy and Materials Science Research Institute Chulalongkorn University Bangkok 10330 Thailand Nanotec-CU Center of Excellence on Food and Agriculture Chulalongkorn UniversityBangkok 10330 Thailand

In present study, a simultaneous electrospinning and electrospraying（SEE） process was employed to produce microclusters of TiO2 nanoparticles and interlock them in nanofibrous network. The photocatalytic composite membranes（PCMs） were fabricated by electrospraying TiO2 nanoparticle suspension into microcluster form that dispersed and entrapped within nylon-6 electrospun fiber membrane. Three PCMs membrane with TiO2 content of 52.0, 83.6,and 91.7 wt.% were successfully fabricated. The membrane consisted of TiO2 microclusters,ranging in sizes from around 0.3 to 10 μm, distributed uniformly within the nylon-6 nanofibrous network. PCMs photocatalytic activity against Methylene Blue（MB） in aqueous solution showed more than 98% MB removal efficiency after 120 min of photocatalytic oxidation（PCO） for all PCMs. For PCM with the highest TiO2 content tested for 5 PCO cycles, it was found that most of their TiO2 content remained incorporated within the nanofibrous structure. The concept of nanoparticles clusters entrapment with SEE fabrication employed here provide a simple and effective method for reducing detachment of nanostructure phase from nanocomposite membrane.

关键词： Nanocomposites Electrospinning Electrospraying TiO2 Photocatalysis

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LZS/Al2O3 glass-ceramic composites sintered by fast firing

LZS/Al2O3 glass-ceramic composites sintered by fast firing

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作者： Arcaro, Sabrina Nieto, Maria Isabel Moreno, Rodrigo Salvador, Maria Dolores Borrell, Amparo Moreno, Berta Chinarro, Eva De Oliveira, Antonio Pedro Novaes Laboratory of Glass-Ceramic Materials VITROCER Federal University of Santa Catarina - UFSC Florianópolis SC88040-900 Brazil Graduate Program in Materials Science and Engineering - PGMAT Federal University of Santa Catarina - UFSC Florianópolis SC88040-900 Brazil Institute of Ceramics and Glass - CSIC Madrid Spain Institute of Materials Technology Polytechnic University of Valencia Spain

In this work, nanometric Al2O3 (1-5 vol.%) particles (13 nm, 100 m2/g) were added to a 19.58Li2O•11.10ZrO2•69.32SiO2 (mol%) (3.5 µm, 2.5 m2/g) parent glass-ceramic matrix to prepare composites with the purpose of studying the influence of Al2O3 on their structure, microstructure, mechanical, thermal and electrical properties when sintered by fast firing. The parent glass-ceramic was prepared by melting and fast cooling (in water) to obtain a glass frit. The resulting glass frit was milled according to a two-step procedure consisting on a dry milling stage followed by a long wet milling step down. Each composition was wet homogenized and then dried at 110 ºC for 48 h for disaggregation. The obtained powders were uniaxially pressed (100 MPa) and compacts sintered by fast firing (175 ºC/min) between 800 and 900 ºC for 30 min. The composites, with relative densities ranging from 89% to 93%, showed zircon and β-spodumene as main crystalline phases. The hardness and Young's modulus varied from 4.5 to 6.5 GPa, and from 65 to 102 GPa, respectively. The formation of β-spodumene in the obtained composites leads to reduce the CTEs, whose values ranged from 13 to 7 x 10-6 ºC-1 © 2017 Universidade Federal de Sao Carlos. All rights reserved.

关键词： Sintering

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Machine-learned molecular surface and its application to implicit solvent simulations

arXiv

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arXiv 2021年

作者： Wei, Haixin Zhao, Zekai Luo, Ray Departments of Materials Science and Engineering Molecular Biology and Biochemistry Chemical and Biomolecular Engineering and Biomedical Engineering Graduate Program in Chemical and Materials Physics University of California IrvineCA92697 United States

Implicit solvent models, such as Poisson-Boltzmann models, play important roles in computational studies of biomolecules. A vital step in almost all implicit solvent models is to determine the solvent-solute interface, and the solvent excluded surface (SES) is the most widely used interface definition in these models. However, classical algorithms used for computing SES are geometry-based, thus neither suitable for parallel implementations nor convenient for obtaining surface derivatives. To address the limitations, we explored a machine learning strategy to obtain a level-set formulation for the SES. The training process was conducted in three steps, eventually leading to a model with over 95% agreement with the classical SES. Visualization of tested molecular surfaces shows that the machine-learned SES overlaps with the classical SES on almost all situations. We also implemented the machine-learned SES into the Amber/PBSA program to study its performance on reaction field energy calculation. The analysis shows that the two sets of reaction field energies are highly consistent with 1% deviation on average. Given its level-set formulation, we expect the machine-learned SES to be applied in molecular simulations that require either surface derivatives or high efficiency on parallel computing platforms. © 2021, CC BY.

关键词： Solvents

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The failure of the Classical Nucleation Theory at low temperatures resolved

arXiv

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arXiv 2019年

作者： Cassar, Daniel R. Serra, André H. Peitl, Oscar Rodrigues, Alisson M. Zanotto, Edgar D. Vitreous Materials Laboratory Department of Materials Engineering Federal University of São Carlos São Carlos SP Brazil Federal University of Sao Carlos Graduate Program in Materials Science and Engineering

A relevant observation about crystal nucleation kinetics in glass-forming substances has been a matter of intense debate for several decades. The Classical Nucleation Theory (CNT) allegedly fails to describe the temperature dependence of the homogeneous crystal nucleation rates below the temperature of maximum nucleation rate. This failure was reported for several glass-forming substances and is known as nucleation "breakdown". Some reasonable explanations for this apparent break have been advanced in the literature, however, the simplest hypothesis has never been tested: that this break is a byproduct of nucleation datasets that have not reached the steady-state regime. In this work, we tested this hypothesis by thoroughly analyzing new and published nucleation data for supercooled Li2Si2O5, BaSi2O5, Na4CaSi3O9, and Na2Ca2Si3O9liquids, using only datasets for which steady-state conditions (likely) have been reached. For that purpose, we used three restraining conditions: i) Nucleation and diffusion data were measured in the same glass batch, and each batch was individually analyzed;ii) only nucleation rate data that passed a steady-state regime test were used in the analysis;iii) the uncertainty and regression confidence bands were computed and considered. With this strategy, we proved that the alleged nucleation break is indeed an experimental artifact! This result ends a four decade-old dilemma and corroborates the use of CNT for analyses of crystal nucleation rates. Copyright © 2019, The Authors. All rights reserved.

关键词： Silicates

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Surface tension assisted dynamic and uniform size generation of 3D spherical hydrogels (STA-DUH) 22

Surface tension assisted dynamic and uniform size generation...

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22nd International Conference on Miniaturized Systems for Chemistry and Life sciences, MicroTAS 2018

作者： Koduri, Manohar Prasad Garden, Tom Hunt, John A. Henstock, James Curran, Judith Tseng, Fan-Gang International Intercollegiate PhD Program NTHU Hsinchu Taiwan Department of Mechanical Materials and Aerospace School of Engineering University of Liverpool United Kingdom School of Science and Technology Nottingham Trent University NottinghamNG11 8NS United Kingdom Institute of Ageing and Chronic Disease William Henry Duncan Building University of Liverpool United Kingdom Engineering and System Science Frontier Research Center on Fundamental and Applied Sciences of Matters National Tsing Hua University Taiwan

ISBN: (纸本)9781510897571

Technologies like additive manufacturing, microfluidics, and electrospray show a possibility of generating a variety of 3-Dimensional structures but seriously suffer in adapting and utilizing the wide variety of available biocompatible materials because of innate diverse physical and chemical properties of biomaterials. It is very important to have a technology which can be viable and dynamically adaptable for different types of materials in generating uniform structures. This work presents a novel cell-laden hydrogel generation using the surface tension phenomenon in controlling the size of the hydrogel. Copyright © (2018) by Chemical and Biological Microsystems Society. All rights reserved.

关键词： Surface tension

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Elevated temperature-driven coordinative reconstruction of an unsaturated single-Ni-atom structure with low valency on a polymer-derived matrix for the electrolytic oxygen evolution reaction

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Nanoscale 2024年第15期16卷 7467-7479页

作者： Patil, Rahul Rajput, Anubha Matsagar, Babasaheb M. Chen, Norman C. R. Ujihara, Masaki Salunkhe, Rahul R. Yadav, Praveen Wu, Kevin C.-W. Chakraborty, Biswarup Dutta, Saikat Electrochemical Energy & Sensor Research Laboratory Amity Institute of Click Chemistry Research & Studies Amity University Noida India Department of Chemistry Indian Institute of Technology New Delhi India Department of Chemical Engineering National Taiwan University Taipei10617 Taiwan Molecular Science and Technology Program Taiwan International Graduate Program Academia Sinica Taiwan National Taiwan University Taiwan Graduate Institute of Applied Science and Technology National Taiwan University of Science and Technology Taipei Taiwan Materials Research Laboratory Department of Physics Indian Institute of Technology Jammu India Synchrotron X-ray Facility Raja Ramanna Centre for Advanced Technology Rajendra Nagar Madhya Pradesh 452013 Indore India

A high-temperature pyrolysis-controlled coordination reconstruction resulted in a single-Ni-atom structure with a Ni-Nx-C structural unit (x = N atom coordinated to Ni). Pyrolysis of Ni-phen@ZIF-8-RF at 700 °C resulted in NiNP-NC-700 with predominantly Ni nanoparticles. Upon elevating the pyrolysis temperature from 700 to 900 °C, a coordination reconstruction offers Ni-Nx atomic sites in NiSA-NC-900. A combined investigation with X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, and soft X-ray L3-edge spectroscopy suggests the stabilization of low-valent Niδ+ (0 −2 was achieved. The cell potential recorded with Pt(−)/(+)NiSA-NC-900/NF was much lower than that obtained for other cells, i.e., Pt(−)/NF and NF(−)/(+)NF, which enhances the potentials of low-valent NiSAs for insightful understanding of the OER. At a constant applied potential of 1.61 V (vs. RHE) for 12 h, an small increase in current for initial 0.6 h followed by a constant current depicts the fair stability of catalyst for 12 h. Our results offer an insightful angle into the OER with a coordinatively reconstructed single-Ni-atom structure at lower valency ( © 2024 The Royal Society of Chemistry.

关键词： Reaction kinetics

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Development of Avrami's kinetics to describe growth of Bi-2223 crystals

Development of Avrami's kinetics to describe growth of Bi-22...

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2011 International Conference on Applied Superconductivity and Electromagnetic Devices, ASEMD 2011

作者： Chen, Wu Ming Jiang, Xu Chuan Yavuz, Mustafa Kambe, Shiro School of Materials Science and Engineering University of New South Wales Sydney NSW 2052 Australia Waterloo Institute for Nanotechnology University of Waterloo Waterloo ON N2L 3G1 Canada Human Sensing Program Graduate School of Science and Engineering Yamagata University 4-3-16 Johnan Yonezawa 992-8510 Japan

ISBN: (纸本)9781424478521

The Avrami's kinetics was known to be the best theory to describe Bi-2223 crystals growth. Whereas, it cannot explain the fact that maximum product volume appearing at optimum sintering time during synthesis Bi-2223 crystal. Meanwhile, the Avrami's equation can also be used to determine the activation energy of Bi-2223 crystal growth;unfortunately, the determined activation energy, E, had dispersion as much as hard to be accepted by researchers themselves. To solve those problems, we studied and developed Avrami's kinetics and obtained a developed Avrami's kinetics equation in this research. With the developed Avrami equation, the index of growth, n, and E of Bi-2223 crystals were determined, including the periods of Bi-2223 crystals growing and decomposing. The n and E for Bi-2223 crystals were changing during synthesis period, values of which can be positive, zero or negative for different reaction periods. And the negative E and n were no reports to be found before, which caused by the decomposition of the product. The developed kinetics can describe a phase transformation system that with metastable or stable product. The developed kinetics theory, as a universal theoretical tool, is expected to be widely applied in the science and engineering multidisciplines and their related interdisciplines. © 2011 IEEE.

关键词： Activation energy

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Terahertz Magnetospectroscopy of Gadolinium Gallium Garnet in Fields up to 25 T

Terahertz Magnetospectroscopy of Gadolinium Gallium Garnet i...

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JSAP-OSA Joint Symposia, JSAP 2021

作者： Bao, J. Peraca, N. Marquez Tay, F. Kritzell, T.E. Li, X. Noe, G.T. Katayama, I. Takeda, J. Nojiri, H. Yamahara, H. Tabata, H. Baydin, A. Kono, J. Department of Physics and Astronomy Rice University HoustonTX United States Department of Electrical and Computer Engineering Rice University HoustonTX United States Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX United States Department of Physics Graduate School of Engineering Science Yokohama National University Yokohama Japan Institute for Materials Research Tohoku University Sendai Japan Department of Electrical Engineering and Information Systems Graduate School of Engineering University of Tokyo Japan Smalley-Curl Institute Rice University HoustonTX United States Department of Materials Science and NanoEngineering Rice University HoustonTX United States

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Phosphors as Sensors for Radiation-Induced Displacement Damage

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MRS Online Proceedings Library 2012年第1期1471卷 68-74页

作者： Gollub, S. L. Harl, R. R. Weeden-Wright, S. L. Rogers, B. R. Walker, D. G. Interdisciplinary Graduate Program in Materials Science Vanderbilt University USA Department of Chemical and Biomolecular Engineering Vanderbilt University USA Department of Electrical Engineering Vanderbilt University USA Department of Mechanical Engineering Vanderbilt University USA

The radiation-induced displacement damage in yttrium borate (YBO3) is studied under X-ray, proton, and alpha irradiation. The photoluminescence (PL) was tested before and after irradiation to determine whether damage occurred and whether it could be queried by examining the PL spectrum. Two different dopants (cerium and europium) were used to activate the phosphor because each provides not only a different spectral signature but also a different mechanism for altering the spectrum between the pre- and post-PL measurements. X-rays, being primarily ionizing radiation, did not show any significant change between the pre and post measurements. We expected protons and alphas to damage the crystal structure, evidence of which could be seen in the change in the spectra before and after irradiation. However, we found no change under alpha exposure (3.6 × 1010 particles/cm2) and a significant change after proton exposure (5 × 1015 particles/cm2). While the material appears to be sensitive to protons, we cannot rule out its sensitivity to alphas because the alpha fluence may be too low to show an effect. This result provides strong indication that our materials are being damaged by particle radiation and that the radiation effects can be quantified.

关键词： luminescence radiation effects optical properties

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Enhancement of Interface Properties between Passivation Layers and InSb by Using Remote PECVD

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AIP Conference Proceedings 2011年第1期1399卷 105-106页

作者： Jaeyel Lee Jong‐Seok Woo Sehun Park Jungsub Kim Changjae Yang Sujin Kim Chulkyun Seok Kang Il Lee Jinsub Park Min‐Koo Han Kwang‐Seok Seo Euijoon Yoon aDepartment of Materials Science and Engineering Seoul National University Seoul Korea dDepartment of Electrical Engineering Seoul National University Seoul Korea bHybrid Materials Program (WCU) Department of Materials Science and Engineering Seoul National University Seoul Korea cDepartment of Nano Science and Technology Graduate School of Convergence Science and Technology Seoul National University Suwon Korea

We report the enhanced interface properties between passivation layers and InSb by using remote PECVD system. SiO2 and Si3N4 layers deposited by remote PECVD showed lower interface trap densities than layers deposited by normal PECVD. SiO2 layers deposited by remote PECVD showed 7.1×1011 cm−2 eV−1 of interface trap density at midgap which is slightly lower than SiO2 layers deposited by PECVD. Si3N4 layers deposited by remote PECVD showed 1.6∼1.7×1012 cm−2 eV−1 at midgap which is 3 times lower than Si3N4 layers deposited by PECVD. Interface properties of SiO2 are superior to that of Si3N4 in both case of PECVD and remote PECVD. To investigate the interface properties between SiO2 and InSb, X‐ray photoelectron spectroscopy was conducted. Indium and antimony oxide phases were found at the interface and these oxide phases could act as the origin of interface traps.

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