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Effect of Order of Addition and Precursor/Reductor Ratio on Direct Synthesis of TiO2 Nanoparticles: Synthesis, Characterization, and Photocatalytic Performance

SSRN

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SSRN 2022年

作者： Goulart, Silviany de Souza Pereira, Mariana Benetti, Renata Martins Bellettini, Gécica Cardoso Elyseu, Fábio Dal-Bó, Alexandre Gonçalves Bernardin, Adriano Michael Graduate Program on Materials Science and Engineering Universidade do Extremo Sul Catarinense Santa Catarina Criciúma88806-000 Brazil Ceramic Materials Group Parque Científico e Tecnológico Santa Catarina Criciúma88807-420 Brazil

Titanium dioxide (TiO2) is the most used semiconductor for heterogeneous photocatalysis. However, there is a limitation of its application, since TiO2 is activated only under ultraviolet radiation. Sunlight has only about 5% of UV radiation and, consequently, there are limitations for the application and commercialization of this semiconductor. The present study aimed to obtain nanostructured TiO2 powders for photocatalysis under UV light by a direct synthesis route, obtaining anatase and rutile phases without further heat treatment. A 2k factorial experimental design was used to evaluate the effect of the order of addition of precursors and their ratio on the synthesis of NPs. TiO2 nanoparticles with large surface area were synthesized via controlled precipitation method. The NPs were characterized by XRD, DSC/TG, FTIR, BET, DLS, ELS, UV-Vis, FESEM-EDS, and photocatalytic activity test. The commercial TiO2 NP P25 was used as standard photocatalyst for comparison with the obtained samples. The surface area measured by the BET method for the synthesized samples was approximately three to five times higher when compared to P25. The photoactivity of the synthesized samples and P25 were determined for the degradation of the methylene blue and rhodamine B dyes under UVA radiation. The results showed that the synthesized samples have an efficiency equivalent to the P25 sample. The synthesis of nanoparticles via the controlled precipitation method using only two reagents proved to be a viable and promising route. The method does not require heat treatment for titanium dioxide crystallization and is still capable of producing a mixture of ideal phases to delay the recombination of the photogenerated electron-hole pair, contributing to the increase of the photocatalytic efficiency. © 2022, The Authors. All rights reserved.

关键词： Titanium dioxide

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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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Chiral metal-organic framework based spin-polarized flexible photodetector with ultrahigh sensitivity

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materials Today Nano 2023年 21卷

作者： Mustaqeem, M. Kamal, S. Ahmad, N. Chou, P.-T. Lin, K.-H. Huang, Y.-C. Guo, G.-Y. Paul Inbaraj, C.R. Li, W.-K. Yao, H.-C. Lu, K.-L. Chen, Y.-F. Department of Chemistry National Taiwan University No. 1 Section 4 Roosevelt Rd Taipei10617 Department of Physics National Taiwan University No. 1 Section 4 Roosevelt Rd Taipei10617 Nano-Science and Technology Program Taiwan International Graduate Program Institute of Physics Academia Sinica Taipei106 Taiwan Institute of Chemistry Academia Sinica Taipei115 Taiwan Department of Materials Science and Engineering National Taiwan University of Science and Technology Taipei10607 Taiwan Institute of Physics Academia Sinica Taipei11529 Taiwan Department of Materials Engineering Ming Chi University of Technology

Spin-optoelectronics plays a key role in developing next-generation technologies with potential applications covering from pharmaceutical synthesis and quantum computing to optical communication. One of the most feasible ways to achieve high-performance spin optoelectronic devices is based on chiral materials. Chiral metal-organic frameworks (CMOFs), an emerging class of chiral hybrid materials, have sparked interest due to their structural variety and flexibility, order nanopores, cost-effectiveness, and unique chirality features. Herein, we have developed CMOF [Sr (9,10-adc) (DMAc)2]n based on achiral building blocks [(9,10-adc)] to detect circularly polarized light (CPL) with ultrahigh sensitivity. Their application in spin-polarized flexible detectors gives a detectivity (D∗) as high as 1.83 × 1012 jones, superior to all reported heterochiral MOF-based detectors. Meanwhile, the anisotropy factor (gIph) is up to 0.38 for CPL detection. The maximum photoresponsivity (Rph) and photogain (η) values of CMOFs reach up to 6.0 × 105 (A/W) and 1.8 × 106, respectively, which are also the record values among reported chiral MOFs. Additionally, the photodetector is mechanically flexible and durable, manifesting an important feature for wearable devices. Therefore, our study shown here is significant and timely to open a route for advancing spin-optoelectronics based on CMOF. © 2023 Elsevier Ltd

关键词： Photodetectors

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Air-liquid microfluidics-integrated surface-enhanced Raman spectroscopy for selective molecular adsorption and detection to achieve bacterial discrimination

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Biosensors and Bioelectronics 2025年 285卷 117576页

作者： Ku, Chi-Yao Chiang, Yu-Wei Hsu, Huai-Yuan Cheng, Ho-Wen Chen, Ko-Lun Han, Yin-Yi Wang, Juen-Kai Wang, Yuh-Lin Huang, Nien-Tsu Graduate Institute of Biomedical Electronics and Bioinformatics National Taiwan University Taipei Taiwan Institute of Atomic and Molecular Sciences Academia Sinica Taipei Taiwan Molecular Science and Technology Taiwan International Graduate Program Academia Sinica Taipei Taiwan International Graduate Program of Molecular Science and Technology National Taiwan University Taipei Taiwan Department of Anesthesiology National Taiwan University Hospital Taipei100229 Taiwan Department of Trauma National Taiwan University Hospital Taipei100229 Taiwan Center for Condensed Matter Sciences National Taiwan University Taipei Taiwan Center for Atomic Initiative for New Materials National Taiwan University Taipei Taiwan Department of Electrical Engineering National Taiwan University Taipei Taiwan

Bacterial discrimination is crucial for accurate microbiological diagnosis and timely antibiotic treatment. Surface-enhanced Raman spectroscopy (SERS) is an ideal technique due to its non-invasive, label-free molecular sensing capabilities. By analyzing bacterial supernatants, containing various purine derivatives, SERS can differentiate bacterial species based on their unique spectral distributions. However, the same bacterial species with different antibiotic resistance may secrete similar purine derivatives, differing only slightly in composition. Furthermore, each purine derivative may have a different molecular affinity to the SERS substrate, making it difficult to distinguish the exact molecular ratio. To improve SERS-based bacterial discrimination, we propose an air-liquid microfluidics-integrated SERS system (ALM-SERS) that selectively adsorbs and detects bacterial secretions. By taking features of precise microdroplet manipulation and contact area from microfluidics and features of selective molecular adsorption and fingerprints characterization from the SERS technique, we successfully perform a "sequential molecular adsorption" strategy to address the signal interference of complicated molecular mixtures in existing SERS methods. As a proof of concept, we first evaluate the molecular affinity of purine derivatives and then demonstrate the competitive analyte adsorption using adenine/cytosine and hypoxanthine/uracil sample mixtures. Finally, we tested six bacterial supernatants, including two Gram types and four strains with identical taxonomy but differing antibiotic resistance. Another six clinically isolated bacterial samples with different antibiotic resistance were also applied. Our results showed that a successful bacterial discrimination between similar species was not possible using a single SERS spectrum. In summary, the ALM-SERS system offers a powerful approach for bacterial discrimination, even when spectral differences are subtle. Beyond microb

关键词： Raman spectroscopy

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A First-Principles and Calphad-Assisted Phase-Field Model for Microstructure Evolution: Application to Mo-V Binary Alloy Systems

SSRN

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SSRN 2023年

作者： Thakur, Abhishek Kumar Kovacevic, Sasa Manga, Venkateswara Rao Deymier, Pierre Alix Muralidharan, Krishna Department of Materials Science and Engineering University of Arizona TucsonAZ85721 United States Department of Civil and Environmental Engineering Imperial College London LondonSW7 2AZ United Kingdom Lunar and Planetary Laboratory University of Arizona TucsonAZ85721 United States Graduate Interdisciplinary Program in Applied Mathematics India

A multiscale computational framework combining the first-principles calculations and the CALPHAD approach with the phase-field method is presented to simulate the microstructure evolution in multicomponent steel alloys. We demonstrate the potential of the framework by predicting the microstructural evolution in elastically periodic arrays of the Mo-V binary sub-system. The framework utilizes the first-principles calculations using special quasi-random structures. Hitherto unavailable thermodynamic and material properties of the alloy are obtained by employing the first-principles calculations and the CALPHAD approach and fed into the phase-field model to predict the microstructure evolution at different temperatures within the miscibility gap region. In addition to the temperature and cooling rates, the model incorporates the role of mechanical fields in decomposition kinetics in the Mo-V binary alloy system. Regimes for temperatures and cooling rates at which spinodal decomposition occurs are identified. Applying external loading leads to directional phase separation in the Mo-V binary system. The elastic inhomogeneity in terms of material properties between the two phases initiates the directional alignment while eigenstrains and applied external loading control the degree of alignment. The framework developed is general and extendable to higher multicomponent sub-systems in steel alloys. © 2023, The Authors. All rights reserved.

关键词： Temperature

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Effect of hydrocooling on postharvest storage of sorrel (Rumex acetosa L.)

Food Chemistry Advances

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Food Chemistry Advances 2023年 3卷

作者： Gomes, Bianca Almada Ferreira de Barros, Hanna Elísia Araújo Natarelli, Caio Vinicius Lima Zitha, Elídio Zaidine Maurício Carvalho, Elisângela Elena Nunes de Barros Vilas Boas, Eduardo Valério Food Science Department Federal University of Lavras P.O. Box 3037 Minas Gerais Lavras 37200-900 Brazil Graduate Program in Materials Science and Engineering Federal University of São Carlos São Paulo São Carlos 13565-905 Brazil

The objective of this work was to determine the effect of the binomial time/temperature of hydrocooling (10 and 20 min at 0 °C, 10 °C, and 20 °C) on the shelf life of sorrel, a non-conventional vegetable. The experimental design was entirely randomized in a 2 × 3 × 6 factorial scheme with three repetitions. The vegetables were stored at 10±1 °C and 99% relative humidity for 10 days. The effects of time and temperature of hydrocooling on physical and chemical characteristics were observed. The degradation of bioactive compounds was higher in the control samples and samples hydrocooled at 0 °C, resulting in lower antioxidant capacity at 10 days. Hydrocooling at 20 °C for 10 min maintained the color of the vegetables until the tenth day, with a chlorophyll content of 34.54 mg.100 g⁻¹, related to the reduction of the respiration rate and weight loss. Hydrocooled sorrel for 20 min at the same temperature showed a vitamin C content of 63.71 mg.100 g⁻¹ and total phenolics of 249.57 mg of EAG.100 g⁻¹ of fresh matter, by the Fast Blue method. Thus, 20 °C for 10 or 20 min was the most efficient parameter for preserving sorrel samples. © 2023

关键词： Artificial neural network Bioative compounds Postharvest losses Pre-cooling. Shelf life Unconventional vegetable

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Effect of pyrolysis temperature on characteristics of tunable magnetic biochar synthesized from watermelon rind and its tetracycline adsorption performance

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Journal of the Taiwan Institute of Chemical Engineers 2024年 160卷

作者： Thairattananon, Phisit Le, Giang T.T. Matsumura, Yukihiko Wu, Kevin C.W. Charinpanitkul, Tawatchai Department of Chemical Engineering Faculty of Engineering Center of Excellence in Particle and Material Processing Technology Chulalongkorn University Bangkok10330 Thailand Institute of Fundamental and Applied Sciences Duy Tan University Ho Chi Minh700000 Viet Nam Faculty of Environmental and Chemical Engineering Duy Tan University Da Nang550000 Viet Nam Mechanical Engineering Program Graduate School of Advanced Science and Engineering Kagamiyama Hiroshima Higashi-Hiroshima739-8527 Japan Department of Chemical Engineering National Taiwan University Taipei10617 Taiwan Department of Chemical Engineering and Materials Science Yuan Ze University Chung-Li Taoyuan Taiwan Research Network of NANOTEC-KU on Nanocatalyst and Nanomaterials for Sustainable Energy and Environment Bangkok10900 Thailand

Background: Tetracycline is an emerging contaminant in water reservoirs, causing undesirable influences on human society. The promising usage of magnetic biochar (MBC) derived from watermelon rind has been explored in the adsorption of various contaminants owing to its high specific surface area and separability;however, the temperature-dependent changes of MBC and its sorption ability toward antibiotics have not been widely examined. Method: Tunable MBCs could be synthesized via simple pyrolysis of watermelon rind impregnated with FeCl3 at different temperatures (700–900 °C). The as-synthesized MBCs were characterized using scanning electron microscopy (SEM), an elemental analyzer, N2 adsorption/desorption, Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffractometry (XRD), and vibrating sample magnetometry (VSM). Then Tetracycline, an emerging contaminant in water reservoirs, was employed as the target contaminant, while adsorption kinetics, isotherm, the effect of pH, and reusability were investigated. Significant findings: The tunability of as-synthesized MBCs could be observed by their distinct changes in structural characteristics when varying pyrolysis temperature. MBC synthesized at 900 °C (MBC900) possessed a high-specific surface area (401 m2.g−1) and saturation magnetization (55.29 emu.g−1), resulting in a greater amount of sorption sites. Tetracycline adsorption by MBCs followed a pseudo-second-order kinetic model and fitted well with the Freundlich model. MBC900 is an excellent adsorbent with a maximum adsorption capacity of 77.6 mg.g−1 and could be used for at least five cycles with an insignificant decrease in the adsorption capacity. © 2024 Taiwan Institute of Chemical Engineers

关键词： Adsorption

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Designing the pressure-dependent shear modulus using tessellated granular metamaterials

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Physical Review E 2023年第3期108卷 034901-034901页

作者： Jerry Zhang Dong Wang Weiwei Jin Annie Xia Nidhi Pashine Rebecca Kramer-Bottiglio Mark D. Shattuck Corey S. O'Hern Department of Mechanical Engineering & Materials Science Yale University New Haven Connecticut 06520 USA Benjamin Levich Institute and Physics Department The City College of New York New York New York 10031 USA Department of Physics Yale University New Haven Connecticut 06520 USA Department of Applied Physics Yale University New Haven Connecticut 06520 USA Integrated Graduate Program in Physical and Engineering Biology Yale University New Haven Connecticut 06520 USA

Jammed packings of granular materials display complex mechanical response. For example, the ensemble-averaged shear modulus 〈G〉 increases as a power law in pressure p for static packings of soft spherical particles that can rearrange during compression. We seek to design granular materials with shear moduli that can either increase or decrease with pressure without particle rearrangements even in the large-system limit. To do this, we construct tessellated granular metamaterials by joining multiple particle-filled cells together. We focus on cells that contain a small number of bidisperse disks in two dimensions. We first study the mechanical properties of individual disk-filled cells with three types of boundaries: periodic boundary conditions (PBC), fixed-length walls (FXW), and flexible walls (FLW). Hypostatic jammed packings are found for cells with FLW, but not in cells with PBC and FXW, and they are stabilized by quartic modes of the dynamical matrix. The shear modulus of a single cell depends linearly on p. We find that the slope of the shear modulus with pressure λc<0 for all packings in single cells with PBC where the number of particles per cell N≥6. In contrast, single cells with FXW and FLW can possess λc>0, as well as λc<0, for N≤16. We show that we can force the mechanical properties of multicell granular metamaterials to possess those of single cells by constraining the end points of the outer walls and enforcing an affine shear response. These studies demonstrate that tessellated granular metamaterials provide a platform for the design of soft materials with specified mechanical properties.

关键词： Jamming Granular solids Mechanical metamaterials

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Characterization of the Root Surface of a Friction Stir Welded Uns S32760 Super Duplex Stainless Steel: Insights into its Microstructure and Corrosion Resistance

SSRN

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SSRN 2023年

作者： Vacchi, G.S. de Carvalho, Willian S. Meinhardt, C.P. Bergmann, Luciano A. Amancio-Filho, Sergio T. Rovere, C.A.D. Munir Rachid Corrosion Laboratory Department of Materials Engineering Federal University of São Carlos Rodovia Washington Luis Km 235 SP São Carlos13565-905 Brazil Federal University of São Carlos Graduate Program in Materials Science and Engineering Brazil Graz University of Technology – TU Graz Institute of Materials Science Joining and Forming BMK Endowed Professorship for Aviation Kopernikusgasse 24/1 Graz8010 Austria Federal University of Pampa Department of Mechanical Engineering Avenida Tiarajú 810 RS Alegrete Brazil Helmholtz-Zentrum Hereon Institute of Materials Mechanics Solid State Materials Processing Max-Planck-Straße 1 Geesthacht Germany

The root surface of a friction stir welded super duplex stainless steel (UNS S32760) was thoroughly characterized in this study. The findings revealed a refined grain structure and a conspicuous increase of 50 HV0.3 in the Root's hardness. Interestingly, the volume fraction of the ferrite phase remained largely unchanged. Rapid cooling in the welding process led to the Cr2N precipitation at the ferrite/ferrite grain boundaries in the root area, significantly increasing sensitization, reducing localized corrosion resistance under high potentials in a neutral pH saline environment, and adversely affecting root passivity in a hydrochloric acid environment compared to the base metal. © 2023, The Authors. All rights reserved.

关键词： Friction stir welding

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Preprocessing Techniques for Enhancing Vision-Based Detection System for Tire Sidewall Extraction

Preprocessing Techniques for Enhancing Vision-Based Detectio...

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International Seminar on Research of Information Technology and Intelligent Systems (ISRITI)

作者： Jia Hao Loo Veronica Lestari Jauw Chin Seong Lim Khairul-Rijal Sarmin Nunung Nurul Qomariyah Ahmad Nurul Fajar Department of Mechanical Materials and Manufacturing Engineering University of Nottingham Malaysia Malaysia Continental Tyre Technology Centre Malaysia Petaling Jaya Malaysia Computer Science Department School of Computing and Creative Arts Bina Nusantara University Jakarta Indonesia Information System Management Department BINUS Graduate Program-Master Information Systems Bina Nusantara University Jakarta Indonesia

ISBN: (数字)9798331519643

ISBN: (纸本)9798331519650

This study aims to develop a system for extracting crucial information from tire sidewalls using Optical Character Recognition (OCR). Initially, images of tire were captured manually by smartphone cameras, including Redmi 9T, iPhone 11, and Galaxy S23 Ultra. The captured images are then transferred to a computer for storage. Subsequently, these images were cropped according to the boundaries identified by Hough Circle Transform (HCT). The cropped images were then further pre-processed. During the pre-processing phase, geometrical transformation and image sharpening techniques are applied to enhance the clarity and readability of the text images. The text is then extracted using Google Vision, with the extracted text categorized by size, DOT, brand and pattern. The results indicated that the effectiveness of image pre-processing was constrained by the accuracy of circle detection, which reached a maximum rate of 87.1%. This causes parts of the text to be cut out inaccurately, leading to a suboptimal extraction accuracy of 55.65%. It is also observed that the Redmi 9T camera produced inconsistent results compared to other devices. Specifically, the iPhone 11 and Samsung Galaxy S23 Ultra demonstrated superior extraction accuracies of 69.71% and 66.37%, respectively, whereas the Redmi 9T achieved a lower extraction accuracy of 37.76%.

关键词： Accuracy Optical character recognition Text categorization Lighting Transforms US Department of Transportation Cameras Tires Internet Data mining

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