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Hydrogen-free carbon monoxide production through decomposition of formic acid over a HPW/TiO2 catalyst
No full textThe dehydration of formic acid over supported phosphotungstic acid (H3PW12O40, HPW) catalysts was investigated for the production of hydrogen-free carbon monoxide (CO). The variations in the support type (SiO2, Al2O3, ZrO2, and TiO2) and HPW content (0.0-20.0 wt.%) affect the acidity of catalysts, which was demonstrated by the temperature-programed desorption of iso-propanol (IPA-TPD) and pyridineadsorbed infrared spectroscopy (Py-IR). The catalytic activity in formic acid dehydration exhibited a volcano-type distribution in accordance with the HPW content and was maximized at 15 wt.% loading. Furthermore, the catalytic activity was more closely related to the density of Bronsted acids than that of Lewis acids and inversely proportional to the peak temperature of propylene desorption during IPATPD. The strongly adsorbed H2O on the catalysts, which is generated during formic acid dehydration, induces deactivation of the catalyst, particularly at lower reaction temperatures (<230 degrees C). (c) 2023 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved
A novel optical coherence tomography-based in vitro method of anti-aging skin analysis using 3D skin wrinkle mimics
No full textBackgroundWrinkles represent a characteristic symptom of skin aging. In recent years, various studies have focused on their prevention and/or cure. However, clinical tests are still the only method available to directly detect and evaluate the anti-wrinkle efficacy of various substances. Moreover, no in vitro strategy for such anti-aging skin analysis has been reported. Therefore, in this study, we aimed to develop a novel technology to overcome these limitations. Materials and methodsFull-thickness (FT) skin wrinkle mimics with various widths and depths were fabricated using a collagen stamping method. These were analyzed and compared using 2D and 3D Swept Source-Optical Coherence Tomography (SS-OCT) imaging technologies. ResultsSS-OCT demonstrated superficial and cross-sectional images of the wrinkle mimics, and the size of the wrinkles was validated using image analysis. Retinoic acid treatment significantly decreased both the depth and width of wrinkles formed in the FT skin wrinkle mimics. ConclusionsUsing 3D tissue engineering and SS-OCT imaging technologies, we developed a novel in vitro technique that can directly detect skin wrinkles. This significantly efficient method could lead to an alternative strategy for animal experiments and preclinical anti-aging research on the skin
Robust topology optimization of continuum structures with smooth boundaries using moving morphable components
No full textTopology optimization has been increasingly used in various industrial designs as a numerical tool to optimize the material layout of a structure. However, conventional topology optimization approaches implicitly describe the structural design and require additional post-processing to generate a manufacturable topology with smooth boundaries. To this end, this paper proposes a novel robust topology optimization approach to produce an optimized topology with smooth boundaries directly. A truncated Karhunen-Loeve expansion and a sparse grid collocation method are integrated with the explicit moving morphable components method for uncertainty representation and propagation, respectively. The performance of the proposed method is assessed on three numerical examples of continuum structures under loading and material uncertainties through comparison with several robust topology optimization approaches. Results show that the proposed method is superior to the benchmark methods in terms of the balance among robustness of the objective function, boundary smoothness, and computational efficiency
Enhanced Optical Contrast and Switching in Near-Infrared Electrochromic Devices by Optimizing Conjugated Polymer Oligo(Ethylene Glycol) Sidechain Content and Gel Electrolyte Composition
No full textA detailed investigation addressing the effects of functionalizing conjugated polymers with oligo(ethylene glycol) (EG(n)) sidechains on the performance and polymer-electrolyte compatibility of electrochromic devices (ECDs) is reported. The electrochemistry for a series of donor-acceptor copolymers having near-infrared (NIR)-optical absorption, where the donor fragment is 3,4-ethylenedioxythiophene (EDOT) or anEG(n) functionalized bithiophene (g2T) and the acceptor fragment is diketopyrrolopyrrole (DPP) functionalized with branched alkyl or EG(n) sidechains, is extensively probed. ECDs are next fabricated and it is found that EG(n) sidechain incorporation must be finely balanced to promote polymer-electrolyte compatibility and provide efficient ion exchange. Proper electrolyte-cation pairing and polymer structural tuning affords a 2x increase in optical contrast (from 12% to 24%) and >60x reduction in switching time (from 20 to 0.3 s). Atomic force microscopy (AFM)/grazing incidence wide-angle X-ray scattering (GIWAXS) characterization of the polymer film morphology/microstructure reveals that an over-abundance of EG(n) sidechains generates large polymer crystallites, which can suppress ion exchange. Lastly, time-of-flight secondary ion mass spectrometry (ToF-SIMS) indicates sidechain/electrolyte identity does not influence the electrolyte penetration depth into the films, and EG(n) sidechain inclusion increases electrolyte cation uptake. The material structural design insight and guidelines regarding the polymer-electrolyte ion insertion/expulsion dynamics reported here should be of significant utility for developing next-generation mixed ionic-electronic conducting materials
Regulating electrostatic phenomena by cationic polymer binder for scalable high-areal-capacity Li battery electrodes
No full textDespite the enormous interest in high-areal-capacity Li battery electrodes, their structural instability and nonuniform charge transfer have plagued practical application. Herein, we present a cationic semi-interpenetrating polymer network (c-IPN) binder strategy, with a focus on the regulation of electrostatic phenomena in electrodes. Compared to conventional neutral linear binders, the c-IPN suppresses solvent-drying-induced crack evolution of electrodes and improves the dispersion state of electrode components owing to its surface charge-driven electrostatic repulsion and mechanical toughness. The c-IPN immobilizes anions of liquid electrolytes inside the electrodes via electrostatic attraction, thereby facilitating Li+ conduction and forming stable cathode-electrolyte interphases. Consequently, the c-IPN enables high-areal-capacity (up to 20 mAh cm-2) cathodes with decent cyclability (capacity retention after 100 cycles = 82%) using commercial slurry-cast electrode fabrication, while fully utilizing the theoretical specific capacity of LiNi0.8Co0.1Mn0.1O2. Further, coupling of the c-IPN cathodes with Li-metal anodes yields double-stacked pouch-type cells with high energy content at 25 & DEG;C (376 Wh kgcell-1/1043 Wh Lcell-1, estimated including packaging substances), demonstrating practical viability of the c-IPN binder for scalable high-areal-capacity electrodes. Binders employed in battery electrodes are conventionally neutral linear polymers. Here, authors present a cationic semi-interpenetrating polymer network binder to regulate electrostatic phenomena, improving the properties and performance of high-capacity positive electrodes for Li metal batteries
SO2 resistance of V-based catalyst for Selective Catalytic Reduction of NOx with NH3 from WS2 Hydrogen-Reducing
No full textExtending the Shelf-Life of Immunoassay-Based Microfluidic Chips through Freeze-Drying Sublimation Techniques
No full textPoint-of-care testing (POCT) platforms utilizing immunoassay-based microfluidic chips offer a robust and specific method for detecting target antibodies, demonstrating a wide range of applications in various medical and research settings. Despite their versatility and specificity, the adoption of these immunoassay chips in POCT has been limited by their short shelf-life in liquid environments, attributed to the degradation of immobilized antibodies. This technical limitation presents a barrier, particularly for resource-limited settings where long-term storage and functionality are critical. To address this challenge, we introduce a novel freeze-dry sublimation process aimed at extending the shelf-life of these microfluidic chips without compromising their functional integrity. This study elaborates on the mechanisms by which freeze-drying preserves the bioactivity of the immobilized antibodies, thereby maintaining the chip's performance over an extended period. Our findings reveal significant shelf-life extension, making it possible for these POCT platforms to be more widely adopted and practically applied, especially in settings with limited resources. This research paves the way for more accessible, long-lasting, and effective POCT solutions, breaking down previous barriers to adoption and application
Multi-Layered Triboelectric Nanogenerators with Controllable Multiple Spikes for Low-Power Artificial Synaptic Devices
No full textIn the domains of wearable electronics, robotics, and the Internet of Things, there is a demand for devices with low power consumption and the capability of multiplex sensing, memory, and learning. Triboelectric nanogenerators (TENGs) offer remarkable versatility in this regard, particularly when integrated with synaptic transistors that mimic biological synapses. However, conventional TENGs, generating only two spikes per cycle, have limitations when used in synaptic devices requiring repetitive high-frequency gating signals to perform various synaptic plasticity functions. Herein, a multi-layered micropatterned TENG (M-TENG) consisting of a polydimethylsiloxane (PDMS) film and a composite film that includes 1H,1H,2H,2H-perfluorooctyltrichlorosilane/BaTiO3/PDMS are proposed. The M-TENG generates multiple spikes from a single touch by utilizing separate triboelectric charges at the multiple friction layers, along with a contact/separation delay achieved by distinct spacers between layers. This configuration allows the maximum triboelectric output charge of M-TENG to reach up to 7.52 nC, compared to 3.69 nC for a single-layered TENG. Furthermore, by integrating M-TENGs with an organic electrochemical transistor, the spike number multiplication property of M-TENGs is leveraged to demonstrate an artificial synaptic device with low energy consumption. As a proof-of-concept application, a robotic hand is operated through continuous memory training under repeated stimulations, successfully emulating long-term plasticity. Three-layered triboelectric nanogenerator (3-TENG) generates multiple spikes from a single touch and its integration with an organic electrochemical transistor (OECT) to accomplish a highly efficient artificial synaptic device. These multiple spikes not only enhance the triboelectric performance of the TENG but can also be utilized to successfully emulate neural functions by delivering high-frequency gate voltage to the OECT.imag
Reinforcement of cobalt leaching resistance of solidified sludge for disposal of radioactive sludge waste by hot isostatic pressing
No full textCobalt leaching resistance of the solidified radioactive sludge subject to disposal was evaluated. The sludge powders ((Fe2O3), NiO, and Cr2O3) with non-radioactive cobalt powder was homogeneously mixed with ferro frit and treated in hot isostatic pressing process. Although the mixing ratio of the ferro frit in total solidified sludge waste was less than 25% and heating temperature in HIP process was lower than 1000 ??C, the cobalt leachability indices in all the solidified sludge were ranged from 13.9 to 18.4. The study showed the solidified sludge waste satisfied the leachability index criteria for waste disposal, which was six
