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Kuang, Meng, Junhao Li, Jinjun Zhang, Jianhong Ding, Ziwang Zhang, Kangrong Huang, Nan Yang, Ziheng Zhang, Mingming Yang i Haiyong Ni. "A novel Dy3+-activated single-phase white light-emitting phosphor for solid-state lighting". New Journal of Chemistry 45, nr 45 (2021): 21066–73. http://dx.doi.org/10.1039/d1nj04570a.
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Taide, S. T., N. B. Ingle i S. K. Omanwar. "Standard approach for energy transfer scheme and tunable emission for white light-emitting diodes (W-LEDs)". International Journal of Modern Physics B 30, nr 25 (28.09.2016): 1650179. http://dx.doi.org/10.1142/s0217979216501794.
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Rare-earth (RE) activated (Dy[Formula: see text]/Sm[Formula: see text] and Ce[Formula: see text]/Tb[Formula: see text]) polycrystalline CaSO4 phosphors were prepared by co-precipitation method. Powder XRD pattern confirmed their structure and phase, while FE-SEM investigation reflected the particle morphology. The optical absorption and emission analysis were carried out to find efficient energy transfer within codoped phosphors, a possible energy transfer mechanism was discussed and energy transfer efficiencies were calculated. The multicolor emission from these materials suggests sustainable and well-defined approach towards possibility of obtaining tunable emission for producing while light emission, which finds potential applications in field emission display (FED) and white light-emitting diodes (W-LEDs).
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Ding, Jingwen, i Challa V. Kumar. "Non-Covalent Assembly of Multiple Fluorophores in Edible Protein/Lipid Hydrogels for Applications in Multi-Step Light Harvesting and White-Light Emission". Molecules 28, nr 16 (12.08.2023): 6028. http://dx.doi.org/10.3390/molecules28166028.
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The design and production of biodegradable and sustainable non-toxic materials for solar-energy harvesting and conversion is a significant challenge. Here, our goal was to report the preparation of novel protein/lipid hydrogels and demonstrate their utility in two orthogonal fundamental studies—light harvesting and white-light emission. Our hydrogels contained up to 90% water, while also being self-standing and injectable with a syringe. In one application, we loaded these hydrogels with suitable organic donor-acceptor dyes and demonstrated the energy-transfer cascade among four different dyes, with the most red-emitting dye as the energy destination. We hypothesized that the dyes were embedded in the protein/lipid phase away from the water pools as monomeric entities and that the excitation of any of the four dyes resulted in intense emission from the lowest-energy acceptor. In contrast to the energy-transfer cascade, we demonstrate the use of these gels to form a white-light-emitting hydrogel dye assembly, in which excitation migration is severely constrained. By restricting the dye-to-dye energy transfer, the blue, green, and red dyes emit at their respective wavelengths, thereby producing the composite white-light emission. The CIE color coordinates of the emission were 0.336 and 0.339—nearly pure white-light emission. Thus, two related studies with opposite requirements could be accommodated in the same hydrogel, which was made from edible ingredients by a simple method. These gels are biodegradable when released into the environment, sustainable, and may be of interest for energy applications.
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Gao, Pao, Jun Xin, Cheng Feng Yan, Hai Kuan Kong, Jian Jun Chen, Xue Chao Liu i Er Wei Shi. "Research on the Key Problems in the Industrialization of SiC Substrate Materials". Materials Science Forum 963 (lipiec 2019): 56–59. http://dx.doi.org/10.4028/www.scientific.net/msf.963.56.
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The development of semiconductor materials and devices will lead to a new industrial technology revolution, in which the Silicon Carbide (SiC) substrate material has very excellent performance and it is especially suitable for manufacturing wave length lasers, white light emitting tubes, high-frequency, high-temperature and high-power devices, etc. This paper focuses on solving the key problems for producing large size and low defects of SiC crystals by the PVT method, such as the preparation and purification of the high purity raw material, the simulation of the temperature field, the control of the crystal defects and the growth of the large size SiC crystals.It is critical for the development of SiC industry.
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Kadim, Akeel M. "Zinc Selenide Quantum Dots Light Emitting Devices (ZnSe QDs-LEDs) with Different Organic Polymers". Nano Hybrids and Composites 18 (listopad 2017): 11–19. http://dx.doi.org/10.4028/www.scientific.net/nhc.18.11.
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The physical and chemical characterize of quantum dots (QDs) extensively depend upon the optical and morphological factors such as size and shape. The zinc selenide (ZnSe) quantum dots (QDs) have been prepared by chemical method and used to fabricate quantum dot hybrid junction devices with different types of organics polymers. The optical studies illustrate that the band gap value from the photoluminescence (PL) with high intensity of these QDs is found about 3.1 eV. The electroluminescence's (EL) hybrid devices were demonstrated by room temperature PL and electroluminescence (EL). Current-voltage (I–V) characteristics indicate that the output current is good compared to the few voltages (5.5 V) used which gives good results to get a generation of white light. The EL spectrum reveals a broad emission band covering the range from 350 - 700 nm. The emissions producing this white luminescence were recognized depending on the chromaticity coordinates (CIE 1931). The correlated color temperature (CCT) was found to be about 5759, 3500 and 3498 K for ITO/TPD/ZnSe, ITO/PPV/ZnSe and ITO/PEDOT/ZnSe QDs respectively. Fabrication of EL- hybrid devices from semiconductors materials (ZnSe QDs) with holes injection organic polymer (TPD, PPV and PEDOT) was effective in white light generation.
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Wojtania, Agnieszka, Bożena Matysiak, Monika Mieszczakowska-Frąc, Jacek S. Nowak i Justyna Szwejda-Grzybowska. "Responses of Micropropagated Rhubarb (Rheum rhaponticum) Plantlets to Different Growing Media and Light Conditions in the Greenhouse". Agriculture 13, nr 4 (18.04.2023): 890. http://dx.doi.org/10.3390/agriculture13040890.
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Cultivating red-stalked rhubarb plants is an important source of raw materials for producing health-promoting foods. The quality and quantity of rhubarb crops are significantly dependent on planting material. To obtain high-quality planting material for the value selection of the rhubarb ‘Raspberry’, we evaluated the morphological and physiological responses of micropropagated plantlets to different growth substrates and light quality during early growth ex vitro in the greenhouse. The plantlets were grown in high-EC (GM1) and low-EC (GM2) peat substrates under four light-emitting diodes (LED) light treatments as supplementary lighting (SL) in the wintertime: 100% red (R), 100% blue (B), white light [44.4% green (G), 24.4% B, 28.9% R; 2.2% far red (FR)] and R+B+G+FR (49.4/16.3/10.3/23.8%) light. Compared to the control (natural sunlight), applied LED lighting significantly increased all growth parameters, but only in plantlets grown in GM1 substrate. Among LED treatments, R+B+G+FR light had the most stimulative effect on all growth parameters (length of leaf petioles, leaf area, biomass) and soluble sugar production. Still, it decreased the levels of phenolic compounds in the leaf petioles. Phenolic synthesis, mainly anthocyanins, was the highest under white light (622.8 mg·100 g−1 dry mass), followed by red (601.8 mg·100 g−1), blue (464.4 mg·100 g−1), and R+B+G+FR light (416.4 mg·100 g−1). High anthocyanin accumulation under R-LED light was associated with high antioxidant activity and growth cessation. Hence, for optimal effects related to plant growth and anthocyanin biosynthesis, the use of W-LED lighting is recommended for the early growth ex vitro of micropropagated rhubarb plantlets.
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Li, Qinfeng, Zheng He, Hussein E. Rozan, Chao Feng, Xiaojie Cheng i Xiguang Chen. "An improved blood hemorrhaging treatment using diatoms frustules, by alternating Ca and light levels in cultures". Marine Life Science & Technology 5, nr 3 (18.08.2023): 316–25. http://dx.doi.org/10.1007/s42995-023-00180-3.
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AbstractHemorrhage control requires hemostatic materials that are both effective and biocompatible. Among these, diatom biosilica (DBs) could significantly improve hemorrhage control, but it induces hemolysis (the hemolysis rate > 5%). Thus, the purpose of this study was to explore the influence of Ca2+ biomineralization on DBs for developing fast hemostatic materials with a low hemolysis rate. Here, CaCl2 was added to the diatom medium under high light (cool white, fluorescent lamps, 67.5 µmol m−2 s−1), producing Ca-DBs-3 with a particle size of 40–50 μm and a Ca2+ content of Ca-DBs-3 obtained from the higher concentration CaCl2 group (6.7 mmol L−1) of 0.16%. The liquid absorption capacity of Ca-DBs-3 was 30.43 ± 0.57 times its dry weight; the in vitro clotting time was comparable to QuikClot® zeolite; the hemostatic time and blood loss using the rat tail amputation model were 36.40 ± 2.52 s and 0.39 ± 0.12 g, which were 40.72% and 19.50% of QuikClot® zeolite, respectively. Ca-DBs-3 showed no apparent toxicity to L929 cells (cell viability > 80%) and was non-hemolysis (the hemolysis rate < 2%). This study prepared Ca-DBs-3 with a rapid hemostatic effect and good biocompatibility, providing a path to develop diatom biosilica hemostatic materials.
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Jung, Choong-Hwan, Young-Min Han i Sang-Jin Lee. "Characteristics of Porous YAG:Ce Nano-Powders Phosphor Fabricated by a Solution Combustion Synthesis". Journal of Nanoscience and Nanotechnology 21, nr 9 (1.09.2021): 4886–90. http://dx.doi.org/10.1166/jnn.2021.19259.
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A cerium-doped YAG (Y3Al5O12) phosphor is used as a rare-earth element phosphor for blue light absorption and yellow light emission for a white light source. A solution combustion synthesis, which is a method for producing nano-powder, is a reaction that is spontaneous ignition by reaction heat released through oxidation/reduction reaction between metal nitrate and fuel. Since the reaction speed is fast and it does not go through a separate firing process, it is a method of easily synthesizing nano-powder by simple process. In this study, YAG:Ce nano-powders were prepared by using various fuels in the combustion synthesis method. Depending on the kind of the additive fuel, the reaction of the combustion synthesis process was different, and the shape of the powder particles according to the fuels was also different. The agglomerated particles of nanoparticles were observed and the characteristics of YAG:Ce powders synthesized under various conditions were analyzed.
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Markovskyi, Anton, Vitaliy Gorbenko, Tetiana Zorenko, Karol Bartosiewicz, Alexander Fedorov i Yuriy Zorenko. "Development of Tb1.5Gd1.5Al5O12:Ce Single-Crystalline Film Converters for WLED Using a Liquid Phase Epitaxy Growth Method". Crystals 12, nr 12 (13.12.2022): 1814. http://dx.doi.org/10.3390/cryst12121814.
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The investigation of the structural, luminescent and photoconversion properties (color coordinates, correlated color temperature, color rendering index and luminous efficacy) of the single-crystalline films of Ce3+-doped Tb1.5Gd1.5Al5O12:Ce mixed garnet with variable film thickness was performed in this work. These film converters were grown on undoped Y3Al5O12 substrates using the liquid phase epitaxy technique. When combined directly with blue LEDs that were commercially available in the market, the developed garnet film converters were responsible for producing white light. The trend line on the color coordinate diagram was obtained for the first time for the Tb1.5Gd1.5Al5O12:Ce converters with the systematic variation in film thickness in the range of 45–82 µm. Under 464 nm blue LED excitation, the investigated converters with a thickness of 55 µm resulted in an ideal white color.
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Hu, Lijun, Zhichao Ding, Fei Yan, Kuan Li, Li Feng i Hongqing Wang. "Construction of Hexagonal Prism-like Defective BiOCL Hierarchitecture for Photocatalytic Degradation of Tetracycline Hydrochloride". Nanomaterials 12, nr 15 (5.08.2022): 2700. http://dx.doi.org/10.3390/nano12152700.
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Oxygen vacancy manipulation and hierarchical morphology construction in oxygen-containing semiconductors have been demonstrated to be effective strategies for developing high efficiency photocatalysts. In most studies of bismuth-based photocatalysts, hierarchical morphology and crystal defects are achieved separately, so the catalysts are not able to benefit from both features. Herein, using boiling ethylene glycol as the treatment solution, we developed an etching-recrystallization method for the fabrication of 3D hierarchical defective BiOCl at ambient pressure. The target hierarchical 3D-BiOCl is composed of self-assembled BiOCl nanosheets, which exhibit a hexagonal prism-like morphology on a micron scale, while simultaneously containing numerous oxygen vacancies within the crystal structure. Consequently, the target catalyst was endowed with a higher specific surface area, greater light harvesting capability, as well as more efficient separation and transfer of photo-excited charges than pristine BiOCl. As a result, 3D-BiOCl presented an impressive photocatalytic activity for the degradation of tetracycline hydrochloride in both visible light and natural white light emitting diode (LED) irradiation. Moreover, an extraordinary recycling property was demonstrated for the target photocatalyst thanks to its hierarchical structure. This study outlines a simple and energy-efficient approach for producing high-performance hierarchically defective BiOCl, which may also open up new possibilities for the morphological and crystal structural defect regulation of other Bi-based photocatalysts.
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Gunasekera, Deshani H. A. T., SzeLee Kuek, Denis Hasanaj, Yinfeng He, Christopher Tuck, Anna K. Croft i Ricky D. Wildman. "Three dimensional ink-jet printing of biomaterials using ionic liquids and co-solvents". Faraday Discussions 190 (2016): 509–23. http://dx.doi.org/10.1039/c5fd00219b.
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1-Ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]) and 1-butyl-3-methylimidazolium acetate ([C4C1Im][OAc]) have been used as solvents for the dissolution and ink-jet printing of cellulose from 1.0 to 4.8 wt%, mixed with the co-solvents 1-butanol and DMSO. 1-Butanol and DMSO were used as rheological modifiers to ensure consistent printing, with DMSO in the range of 41–47 wt% producing samples within the printable range of a DIMATIX print-head used (printability parameter < 10) at 55 °C, whilst maintaining cellulose solubility. Regeneration of cellulose from printed samples using water was demonstrated, with the resulting structural changes to the cellulose sample assessed by scanning electron microscopy (SEM) and white light interferometry (WLI). These results indicate the potential of biorenewable materials to be used in the 3D additive manufacture process to generate single-component and composite materials.
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Alamri, Sabri, Paul A. Sürmann, Andrés F. Lasagni i Tim Kunze. "Interference-based laser-induced micro-plasma ablation of glass". Advanced Optical Technologies 9, nr 1-2 (25.02.2020): 79–88. http://dx.doi.org/10.1515/aot-2019-0061.
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AbstractGlass is one of the most important technical surfaces for numerous applications in automotive, optical, and consumer industries. In addition, by producing textured surfaces with periodic features in the micrometre range, new functions can be created. Although laser-based methods have shown to be capable to produce structured materials in a wide amount of materials, due to its transparency large bandgap dielectrics can be only processed in a controlled manner by employing high-power ultra-short pulsed lasers, thus limiting the employable laser sources. In this article, an interference-based method for the texturing of soda-lime glass using a 15 ns pulsed (1 kHz repetition rate) infrared (1053 nm) laser is proposed, which allows fabricating different periodic patterns with micrometre resolution. This method consists on irradiating a metallic absorber (stainless steel) put in direct contact with the glass sample and inducing locally an etching process on the backside of the glass. Then, the produced plasma at the interference maxima positions leads to the local fabrication of well-defined periodic line-like and dot-like surface patterns. The produced patterns are characterised using white light interferometry and scanning electron microscopy.
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Kaur, Sawinder, Vivek Mumbarkar, Paramjit S. Panesar, Sushma Gurumayum i Prasad Rasane. "Exploring the potential of Epicoccum nigrum for pigment production under variable conditions". Pigment & Resin Technology 48, nr 6 (4.11.2019): 555–62. http://dx.doi.org/10.1108/prt-12-2018-0127.
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Purpose The purpose of this study is to isolate yellow pigment producing fungal strain and to determine the media requirement for growth and secondary metabolite production. Design/methodology/approach Fifteen soil samples were collected and studied for a pigment producing fungal sources. Selection of a fungus was based on pigment produced and further conditions, such as effect of media composition and light wavelength on pigment production and growth parameters were optimised. Findings Out of the isolates analysed, Epicoccum nigrum was selected for further study as this strain has the potential for pigment production. Among all the media evaluated, potato dextrose agar (PDA) was found to be the best media for growth and sporulation, whilst sabouraud dextrose agar (SDA) was only 29 per cent as capable as the best medium. The radial growth rate in case of PDA was 3 ± 0.02 mm/day, while in case of SDA, it was only 1.09 mm/day. Whilst starch as a carbon source was found to increase the radial growth to 5.15 ± 0.02 mm/day, sucrose significantly (p < 0.05) influenced the sporulation (224,000 ± 1,550 spores/ml) of Epicoccum nigrum. Amongst the various nitrogen sources analysed, peptone significantly increased (p < 0.05) the radial growth (6.55 ± 0.02 mm/day) as well as sporulation (220,000 ± 2,100 spores/ml). The observations also indicated that E. nigrum is able to sense and differentiate between light in different wavelength ranges and respond differently in growth and sporulation. The light passing through a red colour sheet resulted in better radial growth (8.5 ± 0.02 mm/day) in comparison to unfiltered light (3 ± 0.02 mm/day). Yellow pigment production in terms of hue values was significantly influenced by the presence of dextrose, peptone and darkness. Research limitations/implications The isolated strain could be studied for variable conditions and stress factors for optimal production of the pigment. Recovery and purification studies could be carried out at pilot and industrial scale. Practical implications The isolation of a strain producing valuable microbial pigment will increase the alternatives of natural food colours and enhance the its commercial applications Originality/value This study identifies Epicoccum nigrum as a potential source of microbial pigment and facilitates its growth and production for possible applications in industrial pigment production.
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Keshri, Sanjay, Brian Rogers, Kevin Murphy, Kevin Reynolds, Izabela Naydenova i Suzanne Martin. "Development and Testing of a Dual-Wavelength Sensitive Photopolymer Layer for Applications in Stacking of HOE Lenses". Applied Sciences 11, nr 12 (16.06.2021): 5564. http://dx.doi.org/10.3390/app11125564.
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Diffractive optical elements (DOEs) have been in development for many years and are an exciting technology with the capability to re-direct light, using diffraction rather than refraction. Holographic Optical Elements (HOEs) are a subset of diffractive optical elements for which the photonic structure is created holographically, i.e., by recording a specific interference pattern in a suitable, photosensitive optical material. Volume HOEs are of particular interest for some applications because of their very high diffraction efficiency and single diffracted order; however, high dispersion and angular wavelength selectivity still present significant challenges. This paper explores a method for producing a compound DOE useful for situations where elements designed for two separate target wavelengths can be advantageously combined to achieve a highly efficient HOE with reduced dispersion. A photopolymer material consisting of two independently sensitized laminated layers is prepared and used in sequential holographic recording at two different wavelengths. The photonic structures recorded are investigated through examination of their diffraction peaks and comparison with the structure predicted by modeling. Finally, the device is illuminated with an expanded diverging beam at both target wavelengths and with white light, and a strong diffracted beam is observed.
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Martín-Pérez, Lucía, i Enrique Burzurí. "Optimized Liquid-Phase Exfoliation of Magnetic van der Waals Heterostructures: Towards the Single Layer and Deterministic Fabrication of Devices". Molecules 26, nr 23 (4.12.2021): 7371. http://dx.doi.org/10.3390/molecules26237371.
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Van der Waals magnetic materials are promising candidates for spintronics and testbeds for exotic magnetic phenomena in low dimensions. The two-dimensional (2D) limit in these materials is typically reached by mechanically breaking the van der Waals interactions between layers. Alternative approaches to producing large amounts of flakes rely on wet methods such as liquid-phase exfoliation (LPE). Here, we report an optimized route for obtaining monolayers of magnetic cylindrite by LPE. We show that the selection of exfoliation times is the determining factor in producing a statistically significant amount of monolayers while keeping relatively big flake areas (~1 µm2). We show that the cylindrite lattice is preserved in the flakes after LPE. To study the electron transport properties, we have fabricated field-effect transistors based on LPE cylindrite. Flakes are deterministically positioned between nanoscale electrodes by dielectrophoresis. We show that dielectrophoresis can selectively move the larger flakes into the devices. Cylindrite nanoscale flakes present a p-doped semiconducting behaviour, in agreement with the mechanically exfoliated counterparts. Alternating current (AC) admittance spectroscopy sheds light on the role played by potential barriers between different flakes in terms of electron transport properties. The present large-scale exfoliation and device fabrication strategy can be extrapolated to other families of magnetic materials.
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Dedov, Stanislav, Gunter Lehmann i Rudolf Kawalla. "Application of Combined Casting-Forging Process for Production of Durable Lightweight Aluminum Parts". Key Engineering Materials 554-557 (czerwiec 2013): 264–73. http://dx.doi.org/10.4028/www.scientific.net/kem.554-557.264.
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Due to the constant development in the automotive industry, where high performance shared with the maximal comfort and safety at low car body weight are the primary goals, gains the lightweight construction in importance. Materials with light weight, high strength and toughness are being engaged. With this background the material aluminum and its alloys become highly attractive to manufacturers. There are mainly two ways of forming the metal materials: casting or forming. Apart from substitution of one method by another there are also many examples of combining of casting and forging processes in practice. Such approach allows using the advantages of both methods, shortening the process chains and saving energy and resources at the same time. Furthermore the form flexibility can be increased and the product quality can be improved. For higher process efficiency a direct transition from casting to forging operation should be applied, so that the heat loss decreases and no additional heat treatment between these operations is necessary. There are processes known, which allow producing the final parts by casting and forging from one a single heat. The application of such processes requires materials, which have simultaneously good casting and forging properties. The Institute of Metal forming TU Freiberg works intensively on development of combined casting-forging technologies for lightweight aluminum parts. A technological chain for this coupled process followed by precipitation hardening heat treatment was developed (Figure 1). Heat treatable aluminum cast and wrought alloys with 1 – 7 % silicon were applied. By the variation of silicon content the optimal cast, forging and hardening properties were achieved. This technology with high energy efficiency allows producing durable light weight parts from aluminum alloys while the mechanical properties of the final parts are equal to or even higher than those in the conventional processes.
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Camacho, N., J. F. May-Crespo, J. B. Rojas-Trigos, K. Martinez, E. Marin i G. C. Mondragon-Rodriguez. "Thermal properties and degradation kinetics of epoxy-γ-alumina and epoxy-zinc oxide light weight composites". Revista Mexicana de Física 66, nr 4 Jul-Aug (1.07.2020): 479. http://dx.doi.org/10.31349/revmexfis.66.479.
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Lightweight composite materials are the gold standard in aeronautical and aerospace applications due to their strength and low mass. To carry higher payloads and decrease launching costs, nanosatellites lightweight. Additionally, nanosatellites must also resist high thermal radiation loads while working in orbit. Polymer-based composite materials maintain low mass and added reinforcing ceramic fillers contributes to increasing radiation resistance, thus producing composites that meet both requirements. In this work, the effects of γ-alumina (Al2O3) and zinc oxide (ZnO) micro- and nanoparticles on the thermal properties and degradation kinetics of epoxy-based composites were investigated. The effective thermal conductivity improved up to 17.8 % for epoxy/γ-Al2O3 and 27.4 % for epoxy/ZnO. The effective thermal diffusivity values show a monotonic decreasing behavior as a function of the particle concentration for the epoxy/γ-Al2O3 composites; for the epoxy/ZnO composites, no correlation on the effective thermal diffusivity values with the ZnO-content was observed. Both oxide-based ceramic fillers increase the thermal stability of epoxy up to 250 °C; however, γ-Al2O3 decreased the maxima decomposition temperature of the epoxy matrix by 6°C. Zinc oxide did not affect the maxima decomposition temperature but decreased the activation energy of epoxy by ~ 45 %. These results provide a feasible manufacturing method for epoxy-based composite materials (i.e. nanosatellites) where efficient heat transfer, heat resistance, and low mass are required.
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Maletin, Aleksandra, Ivan Ristić, Aleksandra Nešić, Milica Jeremić Knežević, Daniela Đurović Koprivica, Suzana Cakić, Dušica Ilić, Bojana Milekić, Tatjana Puškar i Branka Pilić. "Development of Light-Polymerized Dental Composite Resin Reinforced with Electrospun Polyamide Layers". Polymers 15, nr 12 (7.06.2023): 2598. http://dx.doi.org/10.3390/polym15122598.
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As the mechanical properties of resin-based dental composite materials are highly relevant in clinical practice, diverse strategies for their potential enhancement have been proposed in the extant literature, aiming to facilitate their reliable use in dental medicine. In this context, the focus is primarily given to the mechanical properties with the greatest influence on clinical success, i.e., the longevity of the filling in the patient’s mouth and its ability to withstand very strong masticatory forces. Guided by these objectives, the goal of the present study was to ascertain whether the reinforcement of dental composite resins with electrospun polyamide (PA) nanofibers would improve the mechanical strength of dental restoration materials. For this purpose, light-cure dental composite resins were interspersed with one and two layers comprising PA nanofibers in order to investigate the influence of such reinforcement on the mechanical properties of the resulting hybrid resins. One set of the obtained samples was investigated as prepared, while another set was immersed in artificial saliva for 14 days and was subsequently subjected to the same set of analyses, namely Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). Findings yielded by the FTIR analysis confirmed the structure of the produced dental composite resin material. They also provided evidence that, while the presence of PA nanofibers did not influence the curing process, it strengthened the dental composite resin. Moreover, flexural strength measurements revealed that the inclusion of a 16 μm-thick PA nanolayer enabled the dental composite resin to withstand a load of 3.2 MPa. These findings were supported by the SEM results, which further indicated that immersing the resin in saline solution resulted in a more compact composite material structure. Finally, DSC results indicated that as-prepared as well as saline-treated reinforced samples had a lower glass transition temperature (Tg) compared to pure resin. Specifically, while pure resin had a Tg of 61.6 °C, each additional PA nanolayer decreased the Tg by about 2 °C, while the further reduction was obtained when samples were immersed in saline for 14 days. These results show that electrospinning is a facile method for producing different nanofibers that can be incorporated into resin-based dental composite materials to modify their mechanical properties. Moreover, while their inclusion strengthens the resin-based dental composite materials, it does not affect the course and outcome of the polymerization reaction, which is an important factor for their use in clinical practice.
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Shen, Wan Xia, Bo Zhang, Yu Feng Zhang, Xue Chao Wang, Qiang Lu i Cheng Wang. "Research on Life Cycle Energy Consumption and Environmental Emissions of Light-Duty Battery Electric Vehicles". Materials Science Forum 814 (marzec 2015): 447–57. http://dx.doi.org/10.4028/www.scientific.net/msf.814.447.
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Based on producing and manufacturing process of key components, a light-duty battery electric passenger vehicle was selected as a research object, and the energy consumption and environmental emissions from raw materials production, electric vehicle manufacture and operation process in depth were analyzed. The results showed that, the energy consumption for the whole life cycle of EV was 438GJ. The production and operation process of EV accounted for 18.5% and 81.5%, respectively. The GHGs (including CO2, CH4and N2O) emission was 39.3tCO2-eq. The production and operation processed of EV account for 17% and 83%, respectively. Five kinds of other gases emissions from the production and operation process of EV were as follows: 305kg SOx, 206kg NOx, 133kg PM, 69.3kg CO, and 14.6kg NMVOCs. The production and manufacture of key parts and components account for the largest share of the total energy consumption and environmental emissions. Battery system is in the next place, while motor system is least.
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Bugrov, Konstantin D. "Technological Equipment of Light Alloy Processing Plants and its Representation in the Public Sphere of the USSR (1940s–1980s)". Izvestia of the Ural federal university. Series 2. Humanities and Arts 25, nr 2 (2023): 128–47. http://dx.doi.org/10.15826/izv2.2023.25.2.028.
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This paper examines the history of the largest units of the aviation materials industry (processing of light alloys), i.e. heavy-duty hydraulic presses with a power of more than 15,000 tons, which became the basis of the global aviation industry in the 1960s. The author traces the emergence of these units in the US and the USSR and describes the main centers of their deployment. Based on extensive materials from the media, the author scrutinizes the positioning of the technological equipment of the industry for the processing of light alloys in the public sphere of the USSR. The article demonstrates that in the 1950s, press-building was in the focus of attention of the Soviet public sphere as one of the key areas of scientific and technological development. However, starting with the late 1950s, materials on equipping enterprises for the processing of light alloys almost disappeared from the public domain. The second wave of public interest in the machines of the light alloy industry occurred in the late 1960s; it was associated with a general change in approaches to the positioning of the aviation industry of the USSR, and with the important international contract for the construction of a heavy-duty press in France. At this stage, the Novokramatorsk Heavy Machine-Building Plant turned out to be in the spotlight, while the Ural manufacturers and users of such machines continued to remain under a kind of veil of silence. Therefore, the unique equipment of light alloy processing enterprises in Verkhnyaya Salda and Kamensk-Uralsky, as well as the experience of the Ural Heavy Machine-Building Plant in designing and producing such equipment, did not get a place in the industrial mythology of the region, which makes it difficult to position them as valuable elements of the historical and cultural heritage of the Urals.
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Isenia, Wigbertson Julian, i Eliza Steinbock. "How to Read Dr Betty Paërl’s Whip: Intersectional Visions of Trans/Gender, Sex Worker and Decolonial Activism in the Archive". Feminist Review 132, nr 1 (listopad 2022): 24–45. http://dx.doi.org/10.1177/01417789221137045.
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In this article, the authors take up the historical figure of Dr Betty Paërl, who has surprisingly turned up in very different kinds of specialised archives. The white mathematics professor was located in IHLIA LGBT+ Heritage, the largest queer heritage collection in Europe, as a notable SM sexpert and spokesperson on transgender politics, and also found during archival research into the anti-(neo)colonial struggles of Suriname against the Dutch. Upon closer inspection of the materials, the authors find the recurrent image/item of the whip that presses them to carefully think through how the archive of Dr Paërl casts light on a history that Katherine McKittrick calls being ‘in the shadow of the whip’. The article aims to combine an analysis of these versions of the whip in different visual and discursive registers to detect the liberatory politics underlying her activisms. To do so, the authors develop the intersectional model of the kaleidoscope employed by Dutch Black, migrant and refugee (BMR) feminist theorists to grasp the shifting patterns of power that Paërl battled and embodied as an activist of the anticolonial struggle, for sex workers’ rights, for kinky sex and for transgender people. This is all the more important in the historical study of transgender visual materials that most often arrive in archives via medical and police photography or pornographic materials. The historical researcher, the article argues, should be wary of (re)producing a static vision that would reduce transgender figures to sex and gender politics, or eclipse a vision of trans politics that dilates beyond sexuality.
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Rothschild, Lynn J. "Synthetic biology meets bioprinting: enabling technologies for humans on Mars (and Earth)". Biochemical Society Transactions 44, nr 4 (15.08.2016): 1158–64. http://dx.doi.org/10.1042/bst20160067.
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Human exploration off planet is severely limited by the cost of launching materials into space and by re-supply. Thus materials brought from Earth must be light, stable and reliable at destination. Using traditional approaches, a lunar or Mars base would require either transporting a hefty store of metals or heavy manufacturing equipment and construction materials for in situ extraction; both would severely limit any other mission objectives. Long-term human space presence requires periodic replenishment, adding a massive cost overhead. Even robotic missions often sacrifice science goals for heavy radiation and thermal protection. Biology has the potential to solve these problems because life can replicate and repair itself, and perform a wide variety of chemical reactions including making food, fuel and materials. Synthetic biology enhances and expands life's evolved repertoire. Using organisms as feedstock, additive manufacturing through bioprinting will make possible the dream of producing bespoke tools, food, smart fabrics and even replacement organs on demand. This new approach and the resulting novel products will enable human exploration and settlement on Mars, while providing new manufacturing approaches for life on Earth.
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Ishii, Kelly S., Wenqi Hu, Swapnil A. Namekar i Aaron T. Ohta. "An Optically Controlled 3D Cell Culturing System". Advances in OptoElectronics 2011 (13.12.2011): 1–8. http://dx.doi.org/10.1155/2011/253989.
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A novel 3D cell culture system was developed and tested. The cell culture device consists of a microfluidic chamber on an optically absorbing substrate. Cells are suspended in a thermoresponsive hydrogel solution, and optical patterns are utilized to heat the solution, producing localized hydrogel formation around cells of interest. The hydrogel traps only the desired cells in place while also serving as a biocompatible scaffold for supporting the cultivation of cells in 3D. This is demonstrated with the trapping of MDCK II and HeLa cells. The light intensity from the optically induced hydrogel formation does not significantly affect cell viability.
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Liu, Yan Jun, i Yong Chao Zheng. "Mineral Waste Coupled with Boron Oxide for Producing Active Belite Cement Clinker". Applied Mechanics and Materials 405-408 (wrzesień 2013): 2564–75. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.2564.
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This paper presents a laboratory study on active belite cement clinker using boron oxide as dopant to stabilize high temperature phases of Dicalcium silicate (C2S), and mineral waste as siliceous materials in complete replacement of clay. The clinker samples were soaked in Muffle Furnace at different burning temperatures and for various time durations, and then, cooled down to room temperature using air blower. Quantitative X-ray Diffraction analysis (QXRD) by Rietveld method indicates that major mineral components are Dicalcium Silicate (C2S), Ferrite (C2 (A0.48F1.52) O5) and trace amount of Tricalcium Silicate (C3S) in the cement clinkers. Among them, Dicalcium silicate is over 85 percent, Ferrite around 10 percent and Tricalcium silicate less than 10 percent. Thermogravimetric and Differential Scanning Calorimetric (TGA-DSC) spectrum shows that there is no significant phase change while cement clinker was cooling down, which means significant amount of high temperature polymorphic C2S was stabilized during cooling process. It is agreeable with the results from QXRD analysis. Specifically, among polymorphic belite phases, αH-C2S accounts for around 66% of cement clinker, and αL-C2S for about 22% of cement clinker. In addition, massive belite phase was identified by Scanning Electronic Microscope (SEM) analysis and Light Microscopy analysis. At last, the mechanical tests on active belite cement show that active belite cement clinker has a slow strength development at early ages, but rapid strength gain at 28 days in comparison with belite clinker without adding boron oxide. Thus, this active belite cement clinker demonstrates very promising prospect in sustainable cement industry development. Keywords: Active Belite Cement Clinker; Doped; Boron Oxide; αH-C2S; αL-C2S; Strength Development
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Althabaiti, Shaeel Ahmed, Maqsood Ahmad Malik, Manoj Kumar Khanna, Salem Mohamed Bawaked, Katabathini Narasimharao, Soad Zahir Al-Sheheri, Bushra Fatima i Sharf Ilahi Siddiqui. "One-Pot Facile Synthesis of CuO–CdWO4 Nanocomposite for Photocatalytic Hydrogen Production". Nanomaterials 12, nr 24 (16.12.2022): 4472. http://dx.doi.org/10.3390/nano12244472.
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Hydrogen (H2) is a well-known renewable energy source that produces water upon its burning, leaving no harmful emissions. Nanotechnology is utilized to increase hydrogen production using sacrificial reagents. It is an interesting task to develop photocatalysts that are effective, reliable, and affordable for producing H2 from methanol and acetic acid. In the present study, CuO, CdWO4, and CuO–CdWO4 nanocomposite heterostructures were prepared using a cost-efficient, enviro-friendly, and facile green chemistry-based approach. The prepared CuO, CdWO4, and CuO–CdWO4 nanocomposites were characterized using X-ray diffraction pattern, Fourier-transform infrared spectroscopy, diffuse reflectance ultraviolet–visible spectroscopy, scanning electron microscopy, transmission electron microscopy, selected area electron diffraction (SAED) pattern, N2 physisorption, photoluminescence, and X-ray photoelectron spectroscopy techniques. The synthesized photocatalysts were utilized for photocatalytic H2 production using aqueous methanol and acetic acid as the sacrificial reagents under visible light irradiation. The influence of different variables, including visible light irradiation time, catalyst dosage, concentration of sacrificial reagents, and reusability of catalysts, was studied. The maximum H2 was observed while using methanol as a sacrificial agent over CuO–CdWO4 nanocomposite. This enhancement was due to the faster charge separation, higher visible light absorption, and synergistic effect between the CuO–CdWO4 nanocomposite and methanol.
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Al-Taie, Alya I., i Qasim M. Doos. "Material Selection for Unmanned Aerial Vehicles (UAVs) Wings Using Ashby Indices Integrated with Grey Relation Analysis Approach Based on Weighted Entropy for Ranking". Journal of Engineering 29, nr 7 (1.07.2023): 189–200. http://dx.doi.org/10.31026/j.eng.2023.07.12.
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The designer must find the optimum match between the object's technical and economic needs and the performance and production requirements of the various material options when choosing material for an engineering application. This study proposes an integrated (hybrid) strategy for selecting the optimal material for an engineering design depending on design requirements. The primary objective is to determine the best candidate material for the drone wings based on Ashby's performance indices and then rank the result using a grey relational technique with the entropy weight method. Aluminum alloys, titanium alloys, composites, and wood have been suggested as suitable materials for manufacturing drone wings. The requirements for designing a drone's wings are to make them as light as possible while meeting the stiffness, strength, and fracture toughness criteria. The conclusion indicates that Carbon Fiber-Reinforced Polymer (CFRP) is the best material for producing drone wings. In contrast, wood and aluminum alloys were the cheapest materials when the design had to be inexpensive.
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Atabek, Oguzhan, i Sabahat Burak. "Designing a Teacher’s Handbook: Perspectives of Pre-Service Elementary Teachers Regarding Activities and Songs". International Education Studies 12, nr 11 (25.10.2019): 67. http://dx.doi.org/10.5539/ies.v12n11p67.
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Printed educational materials such as teacher’s handbook may affect the quality of education as much as teachers, curriculum, educational environment, and the other course materials. Perspectives of eighty-two pre-service elementary teachers regarding the activities and songs included in the teacher’s handbook for music course were examined by content analysis for shedding light on the nature of the handbook and for producing knowledge about how an effective teacher’s handbook for music course may be like. Even though the question was deliberately worded to let respondents express their both positive and negative views, the number of respondents who expressed positive views and the frequency of such expressions were considerably lower compared to the negative ones. Inappropriateness for age group and learning outcomes, insufficiency for facilitating learning, requiring hard-to-attain materials, and difficulty of application raised as major concerns for both activates and songs. Additionally, activities were argued to be repetitive and lacking entertainment while songs were criticized for their rhythm, melody, lyrics, quality, and practicability in the classroom.
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Mørkved, P. T., A. K. Søvik, B. Kløve i L. R. Bakken. "Removal of nitrogen in different wetland filter materials: use of stable nitrogen isotopes to determine factors controlling denitrification and DNRA". Water Science and Technology 51, nr 9 (1.05.2005): 63–71. http://dx.doi.org/10.2166/wst.2005.0289.
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Laboratory incubations with varying O2 and NO3 concentrations were performed with a range of filter materials used in constructed wetlands (CWs). The study included material sampled from functioning CWs as well as raw materials subjected to laboratory pre-incubation. 15N-tracer techniques were used to assess the rates of denitrification versus dissimilatory nitrate reduction to ammonium (DNRA), and the relative role of nitrification versus denitrification in producing N2O. The N2O/(N2+N2O) product ratio was assessed for the different materials. Sand, shell sand, and peat sustained high rates of denitrification. Raw light-weight aggregates (LWA) had a very low rate, while in LWA sampled from a functioning CW, the rate was similar to the one found in the other materials. The N2O/(N2+N2O) ratio was very low for sand, shell sand and LWA from functioning CWs, but very high for raw LWA. The ratio was intermediate but variable for peat. The N2O produced by nitrification accounted for a significant percentage of the N2O accumulated during the incubation, but was dependent on the initial oxygen concentration. DNRA was significant only for shell sand taken from a functioning CW, suggesting that the establishment of active DNRA is a slower process than the establishment of a denitrifying flora.
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Hicks, M. John, i Catherine Flaitz. "Occlusal caries formation in vitro: comparison of resinmodified glass ionomer with fluoride-releasing sealant". Journal of Clinical Pediatric Dentistry 24, nr 4 (1.07.2000): 309–14. http://dx.doi.org/10.17796/jcpd.24.4.hv752511776h5001.
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The purpose of this laboratory study was to evaluate caries-like lesion formation in occlusal enamel adjacent to a light-cured resin-modified glass ionomer utilized as a pit and fissure sealant and a conventional light-cured, fluoride-releasing sealant. Fluoride-free prophylaxis was done on occlusal surfaces of 12 caries-free mandibular molar teeth that had not been exposed to the oral cavity. Occlusal surface morphology was examined by SEM on the uncoated specimens. Each tooth was then sectioned into 2 portions buccolingually, producing mesial and distal tooth halve. Occlusal surfaces of mesial tooth halves were prepared for an experimental light-cured resin-modified glass ionomer (RMG) sealant (PH-SE II, ESPE), and for comparison, a light-cured fluoride-releasing pit and fissure (PFS) sealant (Helioseal F, Ivoclar) was placed on occlusal surfaces of the corresponding distal tooth halves. The sealed occlusal surfaces were examined uncoated by SEM to compare RMG and PFS adaptation. After thermocycling in artificial saliva, caries-like lesions were formed in the occlusal surfaces adjacent to RMG and PFS. Longitudinal sections were taken for comparison of lesion formation adjacent to RMG and PFS. Mean lesion depths in occlusal surfaces were 64±17mm for RMG, and 116±27mm for PFS (p<0.05, paired t-test). Occlusal lesions terminated at the point where bonding occurred between the occlusal enamel and RMG or PFS. SEM surface topography demonstrated adequate adaptation of the materials with obliteration of the typical pit and fissure surface morphology by both RMG and PFS. While both the resin-modified glass ionomer and fluoride-releasing sealant materials protected the pit and fissure enamel from caries development, the resin-modified glass ionomer reduced the extent of caries involvement in the adjacent unsealed occlusal incline enamel, when compared with the resin sealant.
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Mironov, Viktor, Tarmo Koppel, Mihails Lisicins i Irina Boiko. "Screen Elements Made of Perforated Steel Tape and their Application for Shielding Electromagnetic Fields". Key Engineering Materials 674 (styczeń 2016): 41–47. http://dx.doi.org/10.4028/www.scientific.net/kem.674.41.
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In the present work the methods for producing flat and three-dimensional shielding screens from the perforated steel tape are proposed. The possible application variants of mentioned screens are offered and analyzed. Main attention is given for producing one-layer and multi-layer screens with cellular structure due to its relatively low weight and technological elasticity – complex three-dimensional structures could be done successfully.Examples of produced shielding screens from the perforated steel tape for protection from electromagnetic fields in different frequency range are offered and tested. The efficiency of a shielding material was determined by measuring the magnetic field before and after applying the shielding material. Distribution of the magnetic field behind the shielding screen was determined by software vector mapping. Shielding efficiency was measured for 1) a three-layer perforated steel screen; 2) an one-layer perforated steel screen - shielding screen was placed in between the magnetic field source and the measurement point forming a two dimensional screen; 3) copper composite sprayed screen. During experimental investigation it was established, that a three-layer perforated steel screen application allowed the 27% reduction in the magnetic field, while one-layer perforated steel screen gave only 12% reduction. Copper composite sprayed screen reduced magnetic field by 15%.Recommendations for producing the multi-layer perforated steel screen accordingly to shielding efficiency are elaborated and laid down. The discussed material carries also ecological significance, since the material is produced by waste products (after stumping etc.). Therefore the production of such materials comes with reduced cost both in light of capital expenditures and ecological footprint.
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Rani, Suman, Bansi Lal, Sumit Saxena i Shobha Shukla. "Modifications in the Structural and Optical Properties of ZnO Nanophosphor on Doping with Tb". Nanoscience & Nanotechnology-Asia 9, nr 3 (4.09.2019): 353–61. http://dx.doi.org/10.2174/2210681208666180221123044.
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Background: The characteristic visible emission from ZnO being attributed to the defect energy states can be tailored by doping as well as by synthesis techniques. Rare-earth elements, among various dopants, are interesting because of their unique emission properties in the visible region. Terbium (Tb), in particular, is reported to contribute significantly to the creation of the defect energy states when doped in ZnO. This study investigated the Tb concentration dependent modifications in the structural and optical properties of ZnO nanophosphor. Methods: Tb (0.1, 0.5, 01.0 mol%) doped nanophosphor powder samples prepared by low temperature precipitation method, were sintered in air at 700oC using a home-built temperature controlled (±1oC) muffle furnace. Powder XRD and EDX spectra at room temperature were recorded using Philips X perts x-ray spectrometer while Jeol JSM-7600F was used to record SEM images. Photoluminescence spectra excited by the 280, 300, 380 and 460nm radiation from a Xe lamp were recorded using Carry 8000 spectrophotometer. Raman spectra excited by 514.5nm radiation from an Ar-ion laser, was investigated using Morrison microscope Olympus Bx 41 while UV-VIS absorption spectra were recorded on UV- 1800 UV-VIS Spectrophotometer. Results: FTIR and XRD spectra showed that the basic ZnO wurtzite crystal structure remained unchanged on doping. However, XRD data analysis indicated that the 0.1 mol% Tb might be incorporated in ZnO unit cell at an interstitial and / or substitutional site(s) while at 0.5 and 1.0 mol% doping levels migration of Tb to the surface could be the dominant process. This was further confirmed by Raman and photoluminescence studies. Broad emission (122nm FWHM) peaking around 510nm was observed when the doped samples were excited with 280 and 300nm radiation while characteristic ZnO emission was observed with 380 and 460nm radiation. The calculated chromaticity color coordinates (x,y) of the emission excited by 280nm in 0.5 mol% doped ZnO were: x=0.29 and y=0.31, which are very close to those of the daylight at noon. Conclusion: Concentration dependent lattice distortions were observed; it was concluded that at 0.1mol% concentration level Tb was incorporated in ZnO lattice resulting in interstitial or substitutional defects. On the other hand, at 0.5 and 1.0 mol% doping levels diffusion of Tb to the surface producing strain due to "hydrostatic like pressure" seemed to be the dominating process; maximum strain was observed at 0.5mol% doping. The calculated chromaticity color coordinates of the 280nm excited emission from ZnO:Tb (0.5mol%) were found to be very close to those of the "day light at noon” indicating the suitability of the material for the realization of white light sources.
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Nádas, József, i Vilmos Rakovics. "High Intensity Broad Spectrum LEDs in the Near Infrared Range". Materials Science Forum 885 (luty 2017): 141–46. http://dx.doi.org/10.4028/www.scientific.net/msf.885.141.
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IR LEDs are widely used in the near-infrared (NIR) spectroscopy, especially in hand-held devices for the detection and measurement of organic materials, allowing faster and cheaper examinations. The -OH, -NH and -CH functional groups found in organic substances can frequently be detected by spectroscopy through absorbance measurement at the resonance wavelength of valence-bond vibrations. The measured wavelengths are 4-2.5 μm, while signal to noise ratio of photon detectors is low due to thermal noise at room temperature. The 1st-3rd harmonic absorption bands are located in the range of the NIR, where smaller signals can be measured effectively in practice. The LEDs have tunable narrow wavelength range therefore they are suitable for such measurements as radiation sources. Further advantages of LEDs compared to incandescent lamps are small dimensions, high efficiency, and low power consumption. In order to tune the emission wavelength of the LED, the composition of the semiconductor light-emitting layer has to be properly set. The change in chemical composition will generally affect the lattice constant too. The crystal defects caused by lattice-mismatch often reduce the efficiency. The emission wavelength is tunable in the quaternary GaInAsP/InP material system meanwhile the lattice-constant remains unchanged. Absorption band of the organic materials is generally broader than the emission spectrum of the LED, therefore a broader emitter is preferred. To achieve this, a number of solutions are known. One of these is to use multiple layers with different composition, where the primary light comes from the active layer at the p-n junction of the diode, then excites the second smaller band gap layer producing longer wavelength secondary light by photoluminescence. The transmitted part of the primary light, together with the secondary light, results in a broader spectrum. This method is not yet implemented in this material system, so my work is focused mainly on this approach.
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Macgilchrist, Felicitas. "Global subjects". Pragmatics. Quarterly Publication of the International Pragmatics Association (IPrA) 22, nr 3 (1.09.2012): 417–45. http://dx.doi.org/10.1075/prag.22.3.04mac.
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What does it mean to represent events from the Holocaust in a graphic novel? And what if this is done not in the stark design of Art Spiegelman’s Maus but in the light ligne claire (known from Tintin)? This paper explores the discursive practices surrounding The Search, a graphic novel produced specifically to teach children and young adults about the Holocaust. It asks how (novel) forms of subjectivation are articulated in the everyday, mundane practices of educational media workers. Drawing on poststructuralist theories of the subject and close micro-analysis of language (and semiotic) practices, the paper presents extracts from ethnographic observations of a team of authors designing teaching and learning materials to accompany The Search. These materials – and their practices of production – are participating in transforming memories of the Holocaust and thus (co)producing forms of globalisation. Findings suggest that while the Holocaust has traditionally been seen as a matter of ‘national’ responsibility, The Search and its teaching materials invite readers to see it as (global/universal) ‘individualised’ responsibility. Students are subjectivated as global subjects: Firstly, as universal-ethical subjects and, secondly, as contingency-tolerant subjects. These materials thus constitute a mundane, everyday element shaping new ways of being.
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Yuan, Cunyang, Fuwei Sun, Haibo Liu, Tianhu Chen, Ziyang Chu, Hanlin Wang, Xuehua Zou, Peixun Zhai i Dong Chen. "Synthesis of CaWO4 as a Photocatalyst for Degradation of Methylene Blue and Carmine under Ultraviolet Light Irradiation". Processes 11, nr 4 (31.03.2023): 1050. http://dx.doi.org/10.3390/pr11041050.
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Photocatalysis is considered a promising method for wastewater treatment; however, most synthesized photocatalysts have complex structures and are costly. Thus, in this study, a novel CaWO4 sample was synthesized by a co-precipitation method in one step. The characteristic results show that CaWO4 has good dispersibility, a large specific surface area, and good photoresponse under UV light. The synthesized CaWO4 can be used to degrade methylene blue (MB) and carmine (CR) under UV light without the addition of oxidants. The effects of a water matrix, including pH value, solid–liquid ratio, light intensity, and initial concentration of pollutants on photocatalytic degradation were studied. According to the optimization of these factors, the optimal photocatalytic degradation condition was found under the catalyst concentration of 1.0 g/L and ultraviolet light intensity of 80 W. The optimal pH is 8.2 for the MB system and 6.0 for the CR system. The optimal photocatalytic degradation of MB and CR at 100 mg/L can be achieved as 100%. According to the results of scavenger experiments, holes and hydroxyl radicals dominate the degradation of MB while hydroxyl radicals and superoxide anions are mainly responsible for the degradation of CR. Further analyses showed that photogenerated electrons generated on the surface of the CaWO4 can form electron–hole pairs, thereby producing hydroxyl radicals and superoxide anions to degrade dyes. In addition, the CaWO4 has a good cycling performance in the process of degrading MB (more than 80% after five cycles). It provides a new idea for the photocatalytic degradation of dyes using mineral-like materials.
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El Chawich, Ghenwa, Joelle El Hayek, Vincent Rouessac, Didier Cot, Bertrand Rebière, Roland Habchi, Hélène Garay i in. "Design and Manufacturing of Si-Based Non-Oxide Cellular Ceramic Structures through Indirect 3D Printing". Materials 15, nr 2 (8.01.2022): 471. http://dx.doi.org/10.3390/ma15020471.
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Additive manufacturing of Polymer-Derived Ceramics (PDCs) is regarded as a disruptive fabrication process that includes several technologies such as light curing and ink writing. However, 3D printing based on material extrusion is still not fully explored. Here, an indirect 3D printing approach combining Fused Deposition Modeling (FDM) and replica process is demonstrated as a simple and low-cost approach to deliver complex near-net-shaped cellular Si-based non-oxide ceramic architectures while preserving the structure. 3D-Printed honeycomb polylactic acid (PLA) lattices were dip-coated with two preceramic polymers (polyvinylsilazane and allylhydridopolycarbosilane) and then converted by pyrolysis respectively into SiCN and SiC ceramics. All the steps of the process (printing resolution and surface finishing, cross-linking, dip-coating, drying and pyrolysis) were optimized and controlled. Despite some internal and surface defects observed by topography, 3D-printed materials exhibited a retention of the highly porous honeycomb shape after pyrolysis. Weight loss, volume shrinkage, roughness and microstructural evolution with high annealing temperatures are discussed. Our results show that the sacrificial mold-assisted 3D printing is a suitable rapid approach for producing customizable lightweight highly stable Si-based 3D non-oxide ceramics.
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Service, R. F. "Organic LEDs Begin Producing Bright White Light". Science 267, nr 5202 (3.03.1995): 1262. http://dx.doi.org/10.1126/science.267.5202.1262.
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Gorbenko, Vitaliy, Tetiana Zorenko, Anna Shakhno, Paweł Popielarski, Andres Osvet, Miroslaw Batentschuk, Alexander Fedorov i in. "Single Crystalline Films of Ce3+-Doped Y3MgxSiyAl5−x−yO12 Garnets: Crystallization, Optical, and Photocurrent Properties". Materials 16, nr 5 (24.02.2023): 1869. http://dx.doi.org/10.3390/ma16051869.
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This research focuses on LPE growth, and the examination of the optical and photovoltaic properties of single crystalline film (SCF) phosphors based on Ce3+-doped Y3MgxSiyAl5−x−yO12 garnets with Mg and Si contents in x = 0–0.345 and y = 0–0.31 ranges. The absorbance, luminescence, scintillation, and photocurrent properties of Y3MgxSiyAl5−x−yO12:Ce SCFs were examined in comparison with Y3Al5O12:Ce (YAG:Ce) counterpart. Especially prepared YAG:Ce SCFs with a low (x, y < 0.1) concentration of Mg2+ and Mg2+–Si4+ codopants also showed a photocurrent that increased with rising Mg2+ and Si4+ concentrations. Mg2+ excess was systematically present in as-grown Y3MgxSiyAl5−x−yO12:Ce SCFs. The as-grown SCFs of these garnets under the excitation of α–particles had a low light yield (LY) and a fast scintillation response with a decay time in the ns range due to producing the Ce4+ ions as compensators for the Mg2+ excess. The Ce4+ dopant recharged to the Ce3+ state after SCF annealing at T > 1000 °C in a reducing atmosphere (95%N2 + 5%H2). Annealed SCF samples exhibited an LY of around 42% and similar scintillation decay kinetics to those of the YAG:Ce SCF counterpart. The photoluminescence studies of Y3MgxSiyAl5−x−yO12:Ce SCFs provide evidence for Ce3+ multicenter formation and the presence of an energy transfer between various Ce3+ multicenters. The Ce3+ multicenters possessed variable crystal field strengths in the nonequivalent dodecahedral sites of the garnet host due to the substitution of the octahedral positions by Mg2+ and the tetrahedral positions by Si4+. In comparison with YAG:Ce SCF, the Ce3+ luminescence spectra of Y3MgxSiyAl5−x−yO12:Ce SCFs greatly expanded in the red region. Using these beneficial trends of changes in the optical and photocurrent properties of Y3MgxSiyAl5−x−yO12:Ce garnets as a result of Mg2+ and Si4+ alloying, a new generation of SCF converters for white LEDs, photovoltaics, and scintillators could be developed.
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Ťažký, Martin, Rudolf Hela i Michala Hubertová. "Cement-Bonded Sub-Base Layers of Walkable and Running Structures for Rainwater Management". Solid State Phenomena 325 (11.10.2021): 150–55. http://dx.doi.org/10.4028/www.scientific.net/ssp.325.150.
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Sub-base layers of walkable and running road structures usually consist of a stable subsoil with sufficient load-bearing capacity under the surface layer itself in the form of concrete covers or prefabricated paving elements. Due to their load-bearing capacity, these sub-base layers are most often constructed using cement-bonded aggregate technology. The current hot topic of rainwater management brings opportunities for the construction of water-permeable structures with good water retention capacity. The retention capacity of such a structure can be ensured in ideal conditions by making this sub-base partially permeable and with an absorbent layer while maintaining its mechanical advantages. The experiment confirmed the possibility of producing cement-bonded sub-base layers using light porous aggregates based on expanded clays. The high absorption rate of the type of aggregate used is a good starting point for increasing the retention capacity of the entire system.
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Azman, Muhammad Imran, Nunthawan Kwangsawart, Jitima Preechawong, Manit Nithitanakul i Pornsri Sapsrithong. "Fabrication of Poly(pentaerythritol tetrakis (3-mercaptopropionate)/dipentaerythritol penta-/hexa-acrylate)HIPEs Macroporous Scaffold with Alpha Hydroxyapatite via Photopolymerization for Fibroblast Regeneration". Crystals 10, nr 9 (24.08.2020): 746. http://dx.doi.org/10.3390/cryst10090746.
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Synthetic biomaterials that can be structured into porous scaffolds for support cell growth have played a role in developing the field of tissue engineering. This research focused on combination of biodegradable emulsion template along with the assisting of low-cost polymerization reaction. The appendage of ester-based surfactant, Hypermer B246, played a vital role which gave an outstanding dispersion in HIPEs system and degradability. PolyHIPEs were prepared by using domestic ultraviolet light source for producing a multiscale porosity material. The morphology showed a promising result of poly(pentaerythritol tetrakis (3-mercaptopropionate)/dipentaerythritol penta-/hexa-acrylate)HIPEs with varied Hypermer B246 surfactant concentration resulting in the pores size increased in between 51.2 ± 9.8 µm to 131.4 ± 26.32 µm. Cellular moieties of poly(TT/DPEHA) HIPEs were confirmed by using SEM while inclusion of hydroxyapatite were confirmed by SEM, FTIR and EDX-SEM and quantified by thermogravimetric analysis. The maximum stress and compressive modulus of the obtained materials were significantly enhanced with HA up to five percent by weight. Poly(TT/DPEHA)HIPEs with HA showed the ability for the cell attachment and the adhesion/proliferation of the cells, suggested that poly(TT/DPEHA) HIPEs with HA were suitable for biomaterial application.
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Joyce, Logan, i Yi Xie. "A Rapid Sintering Method for Cerium Nitride Pellet: A Uranium Mononitride Surrogate". Ceramics 5, nr 4 (18.11.2022): 1009–18. http://dx.doi.org/10.3390/ceramics5040072.
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Uranium mononitride (UN) is a candidate fuel material for light water reactors with higher uranium (U) loading and thermal conductivity than uranium dioxide (UO2). However, the sintering of UN pellets is challenging as the UN powder particles oxidize rapidly at high temperatures unless the oxygen concentration is extremely low. Oxidation during sintering either reduces the relative density of the sintered UN pellet or disintegrates the sintered UN pellet to powder. To address this problem, the present work developed a rapid sintering method for producing highly densified UN surrogate pellets with minimal oxidation. Cerium nitride (CeN) is used as a surrogate for UN to reduce radiation hazards. With the custom-developed fast-heating system, the sintering process was completed within 150 s. The sintering atmosphere was flowing nitrogen (N2). The sintered CeN pellet density was 95% of the theoretical density (TD) or higher. The microstructure was uniform with a 10–25 µm grain size as demonstrated by scanning electron microscopy (SEM) and contained trivial levels of oxides as demonstrated by X-ray diffraction (XRD). The resultant pellets indicate that the rapid sintering method is a promising method to make UN fuel pellets with equivalent or higher density to pellets made by conventional sintering methods, while also being more efficient in time and costs.
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Szczucka-Lasota, Bożena, Tomasz Węgrzyn, Abílio Pereira Silva i Adam Jurek. "AHSS—Construction Material Used in Smart Cities". Smart Cities 6, nr 2 (13.04.2023): 1132–51. http://dx.doi.org/10.3390/smartcities6020054.
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With the level of development of the smart city, there are more and more research sub-areas in which the latest material and technological solutions are used, enabling the proper management and functioning of these cities. On the one hand, the introduced materials and technologies are designed to facilitate the functioning of residents both in the urban space and at home; on the other hand, the implemented solutions strive to be consistent with the principles of sustainable development. As shown in this article, reports on new technical and technological solutions and their positive and negative effects are strongly emphasized in publications on the development of smart cities. The most highlighted materials research in the smart city area concerns smart materials and their characteristics and applications. A research gap in this area is in the presentation of material solutions, particularly materials intended for the load-bearing structures of vehicles (electric vehicles, flying vehicles) or infrastructure elements (buildings, shelters, etc.) designed to increase the durability of the structure while reducing its weight. This paper aims to comprehensively present the most important research areas related to the functioning of smart cities in light of previous research, with particular emphasis on new material solutions used for thin-walled load-bearing structures in smart cities made of AHSS (advanced high-strength steel). These solutions are very essential for smart cities because their use allows for the installation of additional devices, sensors, transmitters, antennas, etc., without increasing the total weight of the structure; they reduce the number of raw materials used for production (lighter and durable thin structures), ensure lower energy consumption (e.g., lighter vehicles), and also increase the passive safety of systems or increase their lifting capacity (e.g., the possibility of transporting more people using transports at the same time; the possibility of designing and arranging, e.g., green gardens on buildings; etc.). AHSS-welded joints are usually characterized by too-low strength in the base material or a tendency to crack. Thus, the research problem is producing a light and durable AHSS structure using welding processes. The research presented in this article concerns the possibility of producing welded joints using the Metal Active Gas (MAG) process. The test methods include the assessment of the quality of joints, such as through visual examination (VT); according to the requirements of PN-EN ISO 17638; magnetic particle testing (MT); according to PN-EN ISO 17638; and the assessment of the selected mechanical properties, such as tensile strength tests, bending tests, and fatigue strength checks. These methods enable the selection of the correct joints, without welding defects. The results have a practical implication; advanced production technology for obtaining AHSS joints can be used in the construction of the load-bearing elements of mobile vehicles or parts of point infrastructure (shelters, bus stops). The obtained joint is characterized by adequate strength for the production of the assumed structures. The originality of the manuscript is the presentation of a new, cheaper, and uncomplicated solution for obtaining an AHSS joint with good mechanical properties. The application of the presented solution also contributes to sustainable development (lower fuel and material consumption use by mobile vehicles) and may contribute to increasing the load capacity of mobile vehicles (the possibility of transporting more people).
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Li, Shuangjiang, Yongfei Wang, Zeyuan Li, Xiaoming Liu i Shengdun Zhao. "Study on the Semi-Solid Thixotropic Forging Forming Process for the Low-Carbon Steel Claw Pole". Materials 16, nr 13 (3.07.2023): 4790. http://dx.doi.org/10.3390/ma16134790.
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Low-carbon steel has been popularly applied in numerous applications because of its unique features, such as good plasticity, high strength, great hardness, and excellent toughness. Additionally, the semi-solid thixotropic forging forming method has been widely used in light alloys, due to its advantages of low forming force and high forming quality, whereas its application in ferrous materials is still limited. In this study, the semi-solid thixotropic forging forming process is proposed for producing the low-carbon steel claw pole, with the main stages being radial forging deformation, isothermal treatment, and forging forming. The effect of the area reduction rate on the effective strain from the cross sections of the radial-forged metal bar was studied using numerical simulations. The effect of the isothermal holding process on the microstructures of radial-forged billets was investigated, to obtain the ideal semi-solid microstructures. The microstructure and mechanical properties of low-carbon steel claw poles from the thixotropic forging experiment are presented and discussed. It was found that when the area reduction rate was 67%, the effective strain at the edge of the metal bar exceeded 5.0, while the effective strain at the center was above 1.2, indicating an excellent quality of forging for the bar. The optimization of the process parameters for preparing low-carbon steel semi-solid billets with fine and globular microstructures was achieved with an area reduction rate of 67%, an isothermal temperature of 1500 °C, and a duration time of 15 min. Moreover, the low-carbon steel claw pole fabricated with the optimized operating parameters was found fully filled, with a sharp profile and a flat surface, where the yield strength and tensile strength increased by 88.5% and 79.8%, respectively, compared to the starting materials.
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Lwin, Wai Wai, Napaphol Puyathorn i Takron Chantadee. "Cold-Pressed Coconut Oil Cream: Preparation and Evaluation". Key Engineering Materials 914 (21.03.2022): 23–29. http://dx.doi.org/10.4028/p-408j21.
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Typically, the emollient effect of the vegetable oil has attributed to its usefulness in skin care preparation. The present study aims to prepare the oil in water emulsion cream containing virgin coconut oil (CO) comprisinghydrophilic and lipophilic surfactants (Tween 80 and Span 80). Stability of creams containing CO upon addition of peppermint oil (PO), co-surfactant (Solutol HS 15, ST), solubilizer (benzyl benzoate, BB) was investigated after the temperature cycling. All prepared creams showed the shear thinning flow behavior. Addition of BB gave the lowest viscosity while that comprising ST exhibited the higher viscosity. The highest viscosity formula was the CO andPO containing cream. The particle size determined using light scattering particle analyzer revealed that the mean particle size of all prepared creamswaslower than 35.56 ± 0.62 µm. The homogenous dispersion of oil globules in emulsion was evident, especially, in formulation II (CO) and IV (COand ST). Although the temperature cycling influenced more or less on the compact structure of gel network of cream, the decrement of viscositywasminimal and not much different for cream containing CO and ST (formulation IV). In addition, the mean particle size wasthe smallest for formulation II (CO) which was followed by formulation IV (CO and ST). There wasthe homogenous dispersion of oil globules in formulation II and IV after temperature cycling. All of the above finding was beneficial for employingCO as the oil phase in producing cream such as the foot massage cream where the addition of ST provided the better stability for the prepared cream containing CO.
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Gomes, Bárbara R., Joana L. Lopes, Lorena Coelho, Mattia Ligonzo, Monica Rigoletto, Giuliana Magnacca i Francesca Deganello. "Development and Upscaling of SiO2@TiO2 Core-Shell Nanoparticles for Methylene Blue Removal". Nanomaterials 13, nr 16 (8.08.2023): 2276. http://dx.doi.org/10.3390/nano13162276.
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SiO2@TiO2 core-shell nanoparticles were successfully synthesized via a simple, reproducible, and low-cost method and tested for methylene blue adsorption and UV photodegradation, with a view to their application in wastewater treatment. The monodisperse SiO2 core was obtained by the classical Stöber method and then coated with a thin layer of TiO2, followed by calcination or hydrothermal treatments. The properties of SiO2@TiO2 core-shell NPs resulted from the synergy between the photocatalytic properties of TiO2 and the adsorptive properties of SiO2. The synthesized NPs were characterized using FT-IR spectroscopy, HR-TEM, FE–SEM, and EDS. Zeta potential, specific surface area, and porosity were also determined. The results show that the synthesized SiO2@TiO2 NPs that are hydrothermally treated have similar behaviors and properties regardless of the hydrothermal treatment type and synthesis scale and better performance compared to the SiO2@TiO2 calcined and TiO2 reference samples. The generation of reactive species was determined by EPR, and the photocatalytic activity was evaluated by the methylene blue (MB) removal in aqueous solution under UV light. Hydrothermally treated SiO2@TiO2 showed the highest adsorption capacity and photocatalytic removal of almost 100% of MB after 15 min in UV light, 55 and 89% higher compared to SiO2 and TiO2 reference samples, respectively, while the SiO2@TiO2 calcined sample showed 80%. It was also observed that the SiO2-containing samples showed a considerable adsorption capacity compared to the TiO2 reference sample, which improved the MB removal. These results demonstrate the efficient synergy effect between SiO2 and TiO2, which enhances both the adsorption and photocatalytic properties of the nanomaterial. A possible photocatalytic mechanism was also proposed. Also noteworthy is that the performance of the upscaled HT1 sample was similar to one of the lab-scale synthesized samples, demonstrating the potentiality of this synthesis methodology in producing candidate nanomaterials for the removal of contaminants from wastewater.
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Campos Montiel, S., S. Jiménez-Sandoval, L. Lira i R. Carranza Lopez-Padilla. "Design of a 1 ampere high-precision thin-film resistive current transducer with negligible frequency dependence from DC to 100 KHz". Revista Mexicana de Física 66, nr 5 Sept-Oct (1.09.2020): 589. http://dx.doi.org/10.31349/revmexfis.66.589.
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Currently, non-linear loads are found virtually anywhere with the promise of high electrical efficiency. Examples of this type of non-linear loads are compact fluorescent lamps and light-emitting diode lamps which can now be found in any home. However, they produce highly distorted currents that pollute the power grid and cause stability problems, and making the measurement of the distorted electrical current a non-trivial issue. For the reliable measurement of distorted waveforms within a wide bandwidth, magnetic current transducers present disadvantages over resistive current transducers, such as those caused by the magnetic material which attenuates the high-frequency components while producing heating on the magnetic material. This research presents the design principles to develop a thin-film wideband current transducer. Principles such as the selection of high-purity materials, high-symmetry coaxial design, size, geometry, and aspect ratios were used to obtain a linear relationship between its input and output, i.e.: a flat frequency response from DC to 100 kHz, and the ability to operate continuously with a custom passive thermal system for heat dissipation and reliable measurement. An exhaustive effort has been made on the refinement of the design aimed at understanding the effects that govern the frequency behavior of the transducer and the ways to compensate them. The manufacturing feasibility of the proposed design is well confirmed by the results obtained from the simulation process.
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Zhang, Qilin, Haichao Li, Zongwei Guo i Feng Xu. "High Purity and Low Molecular Weight Lignin Nano-Particles Extracted from Acid-Assisted MIBK Pretreatment". Polymers 12, nr 2 (8.02.2020): 378. http://dx.doi.org/10.3390/polym12020378.
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A simple and economical biorefinery method, organosolv methyl isobutyl ketone (MIBK) pretreatment assisted by Lewis acid ferric trichloride hydrolysis, was proposed for fractionating the lignin from extractive-free Eucalyptus powder at the nanoscale, accompanied by another product furfural, derived from hemicellulose. Under the conditions (180 °C, 1 h) optimized based on the best yield of furfural, 40.13% of the acid-insoluble lignin (AIL) could be obtained with a high purity of 100%, a low molecular weight of 767 (Mn) and improved thermostability. The extracted lignin was characterized by its chemical structure, thermostability, homogeneity, molecular weight, and morphology as compared with milled wood lignin (MWL). The results showed significant variations in chemical structures of the extracted lignin during the pretreatment. Specifically, the aryl ether linkage and phenylcoumarans were broken severely while the resinols were more resistant. The G-type lignin was more sensitive to degradation than the S-type, and after the pretreatment, H-type lignin was formed, indicating the occurrence of a demethoxylation reaction at high temperature. Moreover, the lignin nano-particles were identified visually by AFM and TEM images. The dynamic light scattering (DLS) showed that the average diameter of the measured samples was 131.8 nm, with the polydispersity index (PDI) of 0.149. The MIBK-lignin nano-particles prepared in our laboratory exhibit high potentials in producing high functional and valuable materials for the application in wide fields.
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Kim, W. G., J. K. Park i W. Y. Lee. "Tissue-Engineered Heart Valve Leaflets: An Effective Method of Obtaining Acellularized Valve Xenografts". International Journal of Artificial Organs 25, nr 8 (sierpień 2002): 791–97. http://dx.doi.org/10.1177/039139880202500807.
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To determine the most effective method of producing the acellularized xenograft heart valve leaflets, we compared pathological findings of the xenograft heart valve leaflets produced by three methods; freeze-thawing, Triton and NaCl-SDS treatment and further analyzed the pattern of endothelial cells seeded onto them. Materials and methods Two pigs were sacrificed and three pulmonary valve leaflets were harvested from each animal. They were immediately stored in a tissue preservation solution and assigned in one of the three preparation methods for acellularization. Endothelial cells from the jugular vein of a goat were isolated and seeded onto the acellularized xenograft heart valve leaflets. Light and Electron microscopic analyses were performed. Result and conclusion H & E stain showed that cells were almost absent in the leaflet treated with NaCl-SDS, while cells were partly present in the leaflets treated, one with Triton and the other Freeze-thawing. Transmission microscopic analyses showed cell-free matrix with well preserved collagen architecture under the seeded endothelial cells in the leaflets treated with NaCl-SDS. In conclusion, the valve leaflets treated with NaCl-SDS among three representative methods of acellularization of tissues (freeze-thawing, Triton X-l00, and NaCl-SDS) showed the better results than the others in terms of the efficacy of decellularization and response to endothelial cell seeding.
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Yang, Seong Baek, Jungeon Lee, Sabina Yeasmin, Jae Min Park, Myung Dong Han, Dong-Jun Kwon i Jeong Hyun Yeum. "Blown Composite Films of Low-Density/Linear-Low-Density Polyethylene and Silica Aerogel for Transparent Heat Retention Films and Influence of Silica Aerogel on Biaxial Properties". Materials 15, nr 15 (2.08.2022): 5314. http://dx.doi.org/10.3390/ma15155314.
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Blown films based on low-density polyethylene (LDPE)/linear low-density polyethylene (LLDPE) and silica aerogel (SA; 0, 0.5, 1, and 1.5 wt.%) were obtained at the pilot scale. Good particle dispersion and distribution were achieved without thermo oxidative degradation. The effects of different SA contents (0.5–1.5 wt.%) were studied to prepare transparent-heat-retention LDPE/LLDPE films with improved material properties, while maintaining the optical performance. The optical characteristics of the composite films were analyzed using methods such as ultraviolet–visible spectroscopy and electron microscopy. Their mechanical characteristics were examined along the machine and transverse directions (MD and TD, respectively). The MD film performance was better, and the 0.5% composition exhibited the highest stress at break. The crystallization kinetics of the LDPE/LLDPE blends and their composites containing different SA loadings were investigated using differential scanning calorimetry, which revealed that the crystallinity of LDPE/LLDPE was increased by 0.5 wt.% of well-dispersed SA acting as a nucleating agent and decreased by agglomerated SA (1–1.5 wt.%). The LDPE/LLDPE/SA (0.5–1.5 wt.%) films exhibited improved infrared retention without compromising the visible light transmission, proving the potential of this method for producing next-generation heat retention films. Moreover, these films were biaxially drawn at 13.72 MPa, and the introduction of SA resulted in lower draw ratios in both the MD and TD. Most of the results were explained in terms of changes in the biaxial crystallization caused by the process or the influence of particles on the process after a systematic experimental investigation. The issues were strongly related to the development of blown nanocomposites films as materials for the packaging industry.
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Spinelli, Giovanni, Rumiana Kotsilkova, Evgeni Ivanov, Vladimir Georgiev, Radost Ivanova, Carlo Naddeo i Vittorio Romano. "Dielectric Spectroscopy and Thermal Properties of Poly(lactic) Acid Reinforced with Carbon-Based Particles: Experimental Study and Design Theory". Polymers 12, nr 10 (20.10.2020): 2414. http://dx.doi.org/10.3390/polym12102414.
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In the present study, polylactic acid (PLA) enriched with carbonaceous particles like multi-walled carbon nanotubes (MWCNTs), graphene nanoplates (GNPs) or a combination of both up 12 wt % of loading are used for producing 3D-printed specimens with fused deposition modeling (FDM) technology which are then experimentally and theoretically investigated. The goal is to propose a non-conventional filaments indicated for additive manufacturing process with improved dielectric and thermal properties, compared to the performances exhibited by the unfilled polymer. In the light of the above, a wide dielectric spectroscopy and a thermal analysis, supported by a morphological investigation, are performed. The results highlight that the introduction of 1-dimensional filler (MWCNTs) are more suitable for improving the dielectric properties of the resulting materials, due to the enhancement of the interfacial polarization and the presence of functionalized groups, whereas 2-dimensional nanoparticles (GNPs) better favor the thermal conduction mechanisms thanks to the lower thermal boundary resistance between the two phases, polymer/filler. In particular, with a loading of 12 wt % of MWCNTs the relative permittivity reaches the value of 5.35 × 103 much greater than that of 3.7 measured for unfilled PLA while for the thermal conductivity the enhancement with 12 wt % of GNPs is about 261% respect the thermal behavior of the neat polymer. The experimental results are correlated to theoretical findings, whereas a design of experiment (DoE) approach is adopted for investigating how the different fillers influence the dielectric and thermal performances of the 3D-printed parts, thus assisting the design of such innovative materials that appear promising for development and applications in the electromagnetic (EM) field and heat transfer.
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Mukherjee, Sanjoy, i Pakkirisamy Thilagar. "Organic white-light emitting materials". Dyes and Pigments 110 (listopad 2014): 2–27. http://dx.doi.org/10.1016/j.dyepig.2014.05.031.
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