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Dudkiewicz, Edyta, Natalia Fidorów-Kaprawy, and Paweł Szałański. "Environmental Benefits and Energy Savings from Gas Radiant Heaters’ Flue-Gas Heat Recovery." Sustainability 14, no. 13 (June 30, 2022): 8013. http://dx.doi.org/10.3390/su14138013.
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This paper demonstrates the need and potential for using waste heat recovery (WHR) systems from infrared gas radiant heaters, which are typical heat sources in large halls, due to the increasing energy-saving requirements for buildings in the EU and the powerful and wide-spread development of the e-commerce market. The types of gas radiant heaters are discussed and the classification of WHR systems from these devices is performed. The article also presents for the first time our innovative solution, not yet available on the market, for the recovery of heat from the exhaust gases of ceramic infrared heaters. The energy analysis for an industrial hall shows that this solution allows for environmental benefits at different levels, depending on the gas infrared heater efficiency, by reducing the amount of fuel and emissions for domestic hot water (DHW) preparation (36.8%, 15.4% and 5.4%, respectively, in the case of low-, standard- and high-efficiency infrared heaters). These reductions, considering both DHW preparation and hall heating, are 16.1%, 7.6% and 3.0%, respectively. The key conclusion is that the innovative solution can spectacularly improve the environmental effect and achieve the highest level of fuel savings in existing buildings that are heated with radiant heaters with the lowest radiant efficiency.
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Grafita, Elizabeth Steffina. "Study of PET Spectral Absorbance in Designing Infrared Heating Control of Vacuum Forming Machine." ACMIT Proceedings 3, no. 1 (March 18, 2019): 146–54. http://dx.doi.org/10.33555/acmit.v3i1.37.
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Heating process is the first step in vacuum forming that transforms the plastic sheet from its glassy state to rubbery state, pliable enough to be formed to mold’s shape. Infrared ceramic heaters with zoning control are commonly used in thermoforming industry, in which temperature distribution and its consistency throughout processing time become very important in determining the thickness and properties of manufactured parts. Compared to other thermoplastics, Polyethylene Terephthalate (PET) with its crystallization characteristics is known to have narrower process window. Slight uneven temperature distribution and overheating will degrade PET as well as cause visible defects in final product. In order to obtain proper parameter setting of infrared ceramic heater in PET vacuum forming, a numerical approach that considers PET spectral absorbance was deployed and two methods to control temperature were compared. The experiment resulted in a reliable temperature distribution by means of voltage potentiometer control for pre-heating and implanted thermocouple inside ceramic emitter for main heating in PET vacuum forming machine.
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Matsui, Yuko, Terumi Ueda, Yumi Koizumi, Chinatsu Kato, and Yuiko Suzuki. "Crossover trial of the effects of a far-infrared heater that heats the feet with ceramic balls on autonomic nervous activity and mood states." Science Progress 106, no. 1 (January 2023): 003685042311584. http://dx.doi.org/10.1177/00368504231158452.
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Introduction: The accumulation of fatigue and stress creates problems, including reductions in quality of life and productivity. Objectives: To investigate the effects of a far-infrared heater that heats the feet with ceramic balls on autonomic nervous activity and mood states. Methods: This study was performed as a crossover trial. Participants comprised 20 women. On different days, each participant underwent 15 min of foot warming with the far-infrared heater (far-infrared group) or remained seated for 15 min (control group). Autonomic nervous activity (low-frequency component/high-frequency component, high-frequency) and mood states scales (Profile of Mood States Second Edition and Two-Dimensional Mood Scale for Self-monitoring and Self-regulation of Momentary Mood States) during the study intervention were measured and compared between groups. Results: Low-frequency/high-frequency was significantly higher in the control group 10 min after the start of intervention than at baseline ( P = .033). Low-frequency/high-frequency was significantly lower in the far-infrared group than in the control group at 5 min ( P = .027), 10 min ( P = .011), and 15 min ( P = .015). High-frequency was significantly higher in the far-infrared group at 5 min ( P = .008), 10 min ( P = .004), and 15 min ( P = .015) than at baseline. High-frequency 5 min after the start of intervention was significantly higher in the far-infrared group than in the control group ( P = .033). POMS2 scores improved significantly more in the far-infrared group than in the control group, including in fatigue-inertia ( P = .019), tension-anxiety ( P = .025), and total mood disturbance ( P = .019). Finally, the far-infrared group showed greater improvements in Two-Dimensional Mood Scale-Short Term scores such as stability ( P = .002) and pleasure ( P = .013). Conclusion: Using the far-infrared heater to heat the feet with ceramic balls stabilized and improved mood, reduced Fatigue-Inertia and Tension-Anxiety, and alleviated total mood disturbance. Parasympathetic nervous system activation was observed from 5 min after the start of heating, suggesting that short-duration heat stimulation of the feet is effective.
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Lin, R., and R. L. White. "A Ceramic Sample Heater for Variable Temperature Diffuse Reflectance Fourier Transform Infrared Spectroscopy." Instrumentation Science & Technology 24, no. 1 (February 1996): 37–45. http://dx.doi.org/10.1080/10739149608000464.
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Besov, A. S., A. G. Gribovsky, A. V. Kulikov, V. N. Rogozhnikov, and P. V. Snytnikov. "Prospects and advantages of using metal grid catalytic reactors for gas heating systems and household heating appliances." Proceedings of the Russian higher school Academy of sciences, no. 1 (March 29, 2023): 7–17. http://dx.doi.org/10.17212/1727-2769-2023-1-7-17.
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This article aims to acquaint as many specialists in the field of heat engineering and thermal power engineering as possible with the possibilities and advantages of metal-mesh catalytic heaters developed at the Institute of Catalysis SB RAS. They are shown to be fundamentally different from catalytic heaters in which ceramic or glass-fiber structures are used as carriers of oxidation catalysts. Practical examples of the implementation of this technology on the example of a hot water boiler, infrared heaters and other small-sized household appliances are given. It was shown experimentally that the supplied gas is oxidized completely, and the efficiency of the laboratory, even unoptimized sample of hot water boiler determined by the inlet and outlet water temperature is not lower than 85 % in the range from 15 to 100 % of nominal capacity and 93 % in the low-power mode. The presented technology enables smooth regulation of the heater output within the whole range from 1.5 to 10 kW with power overlap factor of about 7.
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Park, Chung Hee, Myoung Hee Shim, and Huen Sup Shim. "Far IR Emission and Thermal Properties of Ceramics Coated Fabrics by IR Thermography." Key Engineering Materials 321-323 (October 2006): 849–52. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.849.
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The purpose of this study was to develop the warm-up suit that is comfortable as well as has good thermal performance. The function of warm-up suit is to keep the body warm and thus to lose it’s weight by sweating. Ceramic powders, such as zirconium and magnesium oxide have been incorporated into the textile structures to utilize the far infrared radiation effect of ceramics, which heat substrates homogeneously by activating molecular motion. Thermal manikin tests were conducted to determine the clothing insulation and evaporative resistance of the selected warm-up suits. Also, the far IR emission effects of ceramics containing laminate on the body heat transfer were evaluated with the thermogram data using IR camera. The results showed that the ceramics inside laminate slightly increased the thermal insulation and the evaporative resistance. Thermogram showed that when the fabric was heated with the thermal manikin, surface mean temperatures of fabrics were increased as the ceramic incorporated, and the heat storage performance was confirmed.
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Jin, Shuai Yong, Kang Kang Guo, Hui Min Qi, Ya Ping Zhu, and Fan Wang. "High Yield Polyborosilazane Precursor for SiBN Ceramics." Advanced Materials Research 1004-1005 (August 2014): 409–14. http://dx.doi.org/10.4028/www.scientific.net/amr.1004-1005.409.
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The processible and high yield polyborosilazane (PBSZ) precursor for SiBN ceramics was prepared by coammonolysis reaction of dichlorosilane and trichloroborazine. The synthesized PBSZ precursor was characterized by Fourier Transform Infrared spectroscopy (FTIR),1H,11B, and29Si Nuclear Magnetic Resonance (NMR), and its ceramic conversion chemistry was investigated by differential scanning calorimetric (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and thermal gravimetric analysis (TGA). The PBSZ precursor is a viscous liquid and changes to an insoluble solid via a cross-linking reaction between the N-H group and Si-H group as post-heated from 60 to 180°C. The insoluble solid is transformed to Si3N4and BN amorphous structures with an approximately 95% ceramic yield after being pyrolyzed to 1000°C.
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Anderlini, Tia K., and Diane Beauchemin. "Improvements to the analytical performance of inductively coupled plasma optical emission spectrometry by coupling a multi-mode sample introduction system to an infrared heated pre-evaporation tube." Journal of Analytical Atomic Spectrometry 33, no. 6 (2018): 1068–75. http://dx.doi.org/10.1039/c8ja00051d.
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Bauer, Reinhard, Leszek J. Golonka, Torsten Kirchner, Karol Nitsch, and Heiko Thust. "Optimization of thermal distribution in ceramics and LTCC structures applied to sensor elements." Microelectronics International 15, no. 2 (August 1, 1998): 34–38. http://dx.doi.org/10.1108/13565369810215618.
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Thermal properties of Pt or RuO2 thick‐film heaters made on alumina, aluminum nitride or low temperature co‐fired ceramics (LTCC) were compared in the first step of our work. Special holes to improve the heat distribution were included. Several heater layouts were analysed. The heat distribution was measured by an infrared camera, at different heating power. Second, the optimization of LTCC constructions was carried out. The simple structure of LTCC permitted the achievement of a high package density. It was possible to integrate a heating element made from special thick‐film ink as a buried film, inside a substrate. An important step in our technology was the making of the holes. A pattern of holes (achieved by punching or laser cutting) around the heating area permitted a changeable heat gradient. The quality of lamination and the structure of the buried elements were investigated with an ultrasonic microscope.
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Sugiyama, Toyohiko, Keiji Kusumoto, Masayoshi Ohashi, and Akinori Kamiya. "Environmental Friendly Ceramic Building Materials." Key Engineering Materials 690 (May 2016): 150–55. http://dx.doi.org/10.4028/www.scientific.net/kem.690.150.
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The global warming is one of the most serious problems. The decrease of CO2 emissions in our daily life is an important subject today. Recently, an application of water retentive materials as a paving material has attracted a great deal of attention in Japan. This material is effective for reducing heat island phenomenon, which is also a recent problem in many cities in Japan. Water retained in the material during rainfall evaporates when heated by sunshine. The latent heat absorbed by evaporating water works to cool the surroundings. The water retentive ceramic products are expected to be useful for building materials as well as pavements. Several performances are required on the water retentive ceramics when it is used as building materials. Its cost and quality are the important factors. Porous ceramic materials formed by pressing without firing is one of ideal low cost and eco-friendly candidates. The porous ceramics is also expected to be produced from recycled ceramic materials. By optimizing its composition and forming method, a water retentive material with high performance was developed. The trial product had the properties as follows; fracture toughness: 1300N, bending strength: 175N/cm, water absorption: larger than 30%, and precision in size (length): +-0.5mm for 150mm. The product showed also enough frost resistance. In this paper, the fundamental properties of the porous ceramics prepared without firing are discussed with referring to the results of the field experiments.Another subject recently studied by several tile manufactures in Japan is the glazed tile with high solar reflectance. The exterior walls covered with such a high solar reflectance tile keeps the surface temperature of the wall lower under the strong sunshine of summer. It is effective against heat-island phenomenon. In this paper, the outline of the research results on visible and infrared reflectance of many kinds of glazes is also discussed.
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Al Hejami, Ahmed, and Diane Beauchemin. "Infrared heating of commercially available spray chambers to improve the analytical performance of inductively coupled plasma optical emission spectrometry." Journal of Analytical Atomic Spectrometry 33, no. 11 (2018): 2008–14. http://dx.doi.org/10.1039/c8ja00239h.
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Xiao, Mi, Xia Wan Wu, and Kuan Xiu Song. "(Ag1-xNax)(Nb1-yTay)O3 Dielectric Ceramic Prepared through Citrate Precursor Method." Key Engineering Materials 280-283 (February 2007): 15–18. http://dx.doi.org/10.4028/www.scientific.net/kem.280-283.15.
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(Ag1-xNax)(Nb1-yTay)O3 (ANNT) dielectric ceramic material with perovskite structure was prepared through a wet chemical synthetic method. The precursor solution for the material was obtained from the citric acid solutions of different metal oxides or nitrates with exact molar ratio by a sol-process. The precursor solution thus prepared was then heated under an infrared lamp to evaporate the solvent. This period showed a self-propagating combustion behavior. Ceramic powder was obtained after the residue was calcined at a certain temperature. It is proved that ANNT sintered at 1040°C was finely grained. The obtained ceramic showed excellent high frequency dielectric properties with considerable high dielectric constant and rather low dissipation factor under 1MHz.
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Klesner, Catherine, Jay A. Stephens, Emilio Rodriguez-Alvarez, and Pamela B. Vandiver. "Reconstructing the Firing and Pigment Processing Technologies of Corinthian Polychrome Ceramics, 8-6th Centuries B.C.E." MRS Advances 2, no. 35-36 (2017): 1889–909. http://dx.doi.org/10.1557/adv.2017.257.
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ABSTRACTDecorative, polychrome ceramics from Corinth, Greece, produced during the 8th-6th centuries B.C.E. were luxury goods widely traded throughout Greece and the Mediterranean. Corinthian pottery is the first 5-color polychrome ceramic technology, having slip-glazes in distinctive white, black, red, yellow, and purple colors, and in a variety of surface finishes from glossy, to semi-matte, to matte. The firing temperature range, 925-1075°C, was determined experimentally to be to be higher than previously reported, similar to the Corinthian amphorae and other ceramic products. This firing range is higher than that of the better known, more prestigious Athenian Black-figure and Red-figure ceramics. In this study three examples of Corinthian and one example of Athenian Black-figure ceramics from the Marie Farnsworth collection at the University of Arizona were tested and compared to thirteen clays from Corinth. Analytical techniques included Fourier-transform infrared spectroscopy (FTIR), scanning-electron microscopy with energy-dispersive spectroscopy (SEM-EDS), micro-Raman spectroscopy, and wavelength-dispersive electron microprobe (EPMA with BSE-SEM).Artisans in Corinthian workshops experimented to change the colors of the slips by varying the type and amount of iron-rich raw material, as well as the composition of the clay used as a binder and the amount of flux used as a sintering aid to promote glass formation. Corinthian artisans developed not only different recipes to produce the various colors, but also they were able to control raw-material particle size and composition to produce variations in surface luster (matte, semi-matte and glossy). This research suggests that Corinthian polychrome-slip technology was based on careful control of particle processing, of compositional control of raw materials and their admixtures, and of firing temperature. The behavior or practice of adding different ratios of pigments and glass-forming fluxes to form various optical effects implies a detailed knowledge of what happens when these are heated and fired. This is a process of experimentation focused on developing a distinctive craft practice, which produced a distinctive and highly valued material. The Corinthians developed a more complex, easily recognizable, and culturally distinctive ceramic technology that was intentionally established as a cultural brand, and probably as a luxury brand of high socio-economic value. This research deepens our understanding of the complex pigment processing and firing technologies employed in the production of Corinthian ceramics.
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Zhang, Shao Peng, Xiao Hui Wang, and Long Tu Li. "Synthesis and Characterization of Nanocrystalline PZT Powders by a Simple Sol-Gel Method." Key Engineering Materials 512-515 (June 2012): 147–52. http://dx.doi.org/10.4028/www.scientific.net/kem.512-515.147.
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Nanocrystalline lead zirconate titanate (PZT) powders with composition at the morphotropic phase boundary (MPB) were synthesized by a simple aqueous based sol-gel method, using lead nitrate, zirconium nitrate and tetrabutyl titanate as the starting materials. The sol could be easily transformed into gel, firstly heated at 120°C for 10h, then at 180°C for 24h. The thermal decomposition process of the gel was investigated by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) techniques. The effect of citrate addition amount on the calcining temperature was discussed. The results reveal that pure perovskite phase PZT powders can be obtained at a calcining temperature as low as 600°C. The average grain size of the powders was determined by transmission electron microscope and X-ray diffraction. The influences of calcining temperature and the pH value of the solution on the grain size were investigated. The sintering temperature and electrical properties of the ceramics derived by nano-powders were compared with those prepared by the conventional ceramic processing. The result shows that using the nanopowder, the sintering temperature could be reduced by about 100°C and the ferroelectric properties were enhanced.
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Preshelkov, Boris, Rosen Borisov, Radoslav Kartov, and Milan Blagojević. "A Study of Determening Safe Distances Between Ceramic Infrared Gas Heaters and Combustible Materials." Safety Engineering 1, no. 1 (October 15, 2011): 7–10. http://dx.doi.org/10.7562/se2011.1.01.02.
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Wang, Moo-Chin, Ming-Hong Lin, and Hok-Shing Liu. "Effect of TiO2 addition on the preparation of β-spodumene powders by sol-gel process." Journal of Materials Research 14, no. 1 (January 1999): 196–203. http://dx.doi.org/10.1557/jmr.1999.0029.
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This study has shown the possibility of achieving two primary considerations for the advanced fabrication of spodumene with a composition of Li2O · Al2O3 · 4SiO2 · nTiO2 (LAST) glass-ceramics by a sol-gel process, namely, an enormous reduction of sintering temperature from 1600 to 1200 °C together with the appearance of simple phases of β-spodumene/rutile as opposed to products via the conventional melting-crystallization process. Fine glass-ceramic powders with a composition of Li2O · Al2O3 · 4SiO2 (LAS) have been synthesized by the sol-gel process using Si(OC2H5)4, Al(OC2H5)3, LiOCH3, and Ti(OC2H5)4 as the starting materials. The process included well-controlled hydrolysis polycondensation of the raw alkoxides. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron diffraction (ED) analysis were utilized to study the effect of TiO2 addition on the preparation of β-spodumene powders by the sol-gel process. The gelation time of the LAST solution increases as the TiO2 content increases. For the low (<3) or high (>11) pH value, the gelation time was shortened. At pH = 5, regardless of the TiO2 content, the gel has the longest time of gelation. When the dried gels of the LAST system are heated from 800 to 1200 °C, the crystallized samples are composed of the major phase of β-spodumene and a minor phase of rutile (TiO2).
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Lau, W. S. "The use of far‐infrared ceramic heaters for radiation heating of glass in vacuum deposition processes." Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 6, no. 1 (January 1988): 163–65. http://dx.doi.org/10.1116/1.575003.
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Zhang, Gui-Yu, Sung-Chul Bae, Run-Sheng Lin, and Xiao-Yong Wang. "Effect of Waste Ceramic Powder on the Properties of Alkali–Activated Slag and Fly Ash Pastes Exposed to High Temperature." Polymers 13, no. 21 (November 2, 2021): 3797. http://dx.doi.org/10.3390/polym13213797.
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This paper presents the effects of alkali-activated blast furnace slag and fly ash (AASF) paste added with waste ceramic powder (WCP) on mechanical properties, weight loss, mesoscopic cracks, reaction products, and microstructure when exposed to 300, 600, and 900 °C. Using waste ceramic powder to replace blast furnace slag and fly ash, the replacement rate was 0–20%. The samples cured at 45 °C for 28 days were heated to 300, 600, and 900 °C to determine the residual compressive strength and weight loss at the relevant temperature. We evaluated the deterioration of the paste at each temperature through mesoscopic images, ultrasonic pulse velocity (UPV), thermogravimetric analysis (TG), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and with a scanning electron microscope (SEM). Relevant experimental results show that: (1) with the increase in waste ceramic powder content, the compressive strength of samples at various temperatures increased, and at 300 °C, the compressive strength of all the samples reached the highest value; (2) the residual weight increased with the increase in the content of the waste ceramic powder; (3) with a further increase in temperature, all the samples produced more mesoscopic cracks; (4) at each temperature, with the rise in waste ceramic powder content, the value of the ultrasonic pulse velocity increased; (5) the TG results showed that, as the content of waste ceramic powder increased, the formation of C-A-S-H gel and hydrotalcite decreased; (6) XRD and FTIR spectra showed that, at 900 °C, the use of waste ceramic powder reduced the formation of harmful crystalline phases; (7) the SEM image showed that, at 900 °C, as the content of waste ceramic powder increased, the compactness of the sample was improved. In summary, the addition of waste ceramic powder can improve the mechanical properties of the alkali-activated paste at high temperatures, reduce the occurrence of cracks, and make the microstructure denser.
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Lu, Huan, Shu Long Wang, Ning He, Liang Li, and Xiu Qing Hao. "Heat Transfer Model for Pulse Laser Assisted Machining of ZrO2." Materials Science Forum 836-837 (January 2016): 430–35. http://dx.doi.org/10.4028/www.scientific.net/msf.836-837.430.
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Laser assisted machining (LAM) is one important solution for machining difficult-to-machine materials. The heat transfer model of quasi steady state in laser assisted micro machining is built, and the simulation software for temperature distribution measurement is developed based on MATLAB. The simulated temperature distribution of the ZrO2 ceramic heated by pulse laser shows a good agreement of tendency with the corresponding experimental results through the infrared temperature measurement method, while the simulated temperature is consistently overestimated. This difference maybe results from the neglect of the heat loss caused by the heat radiation and the heat convection in the model. The proposed model in this paper could provide reference for the selection of optimal process parameters and improve the machining quality, which are closely related to the temperature distribution.
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Ranga, Narender, Atul Kumar, C. R. Mariappan, and Surender Duhan. "In-Vitro Study of Sol Gel Synthesized Bioactive Glass Ceramics for Anti-Microbial Properties." Journal of Nanoscience and Nanotechnology 21, no. 3 (March 1, 2021): 1606–12. http://dx.doi.org/10.1166/jnn.2021.18978.
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In this research work new type of bioglass ceramics successfully synthesized the bioglass composition: 50SiO2−30CaO−10P2O5−10MgO by sol–gel technique which was further heated up to 600 °C. Different characterization techniques were applied on the prepared bioglass powder to obtain the structural information. X-ray powder diffraction (XRD) and fourier-transform infrared spectroscopy (FTIR) analysis confirms the amorphous nature and apatite formation on surface of the sample. The time dependent biological activity was tested on immersed samples with simulated body fluid (SBF). Structural configuration of the hydroxyapatite layer along with nano-size as well as texture properties of the samples were confirmed using field emission scanning electron microscope (FE-SEM), high-resolution transmission electron microscopy (HR-TEM) and Brunauer–Emmett–Teller (BET) techniques, respectively. It was found that magnesium performs a pivotal role in bone proliferation and improves the thermophysical properties of the synthesized bioglass ceramics. The antibacterial effects were studied by two well-known pathogen Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus).
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Yoshito, Walter Kenji, Marcos A. Scapin, Valter Ussui, Dolores Ribeiro Ricci Lazar, and José Octavio Armani Paschoal. "Combustion Synthesis of NiO/YSZ Composite." Materials Science Forum 591-593 (August 2008): 777–83. http://dx.doi.org/10.4028/www.scientific.net/msf.591-593.777.
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Nickel oxide-yttria stabilized zirconia (NiO-YSZ) anode materials were synthesized by combustion process involving metal nitrate-urea decomposition. The precursor was heated to evaporate water undergoing dehydration, and then the mixtures froth and swell. Further heating produces large amounts of gases that ignite at ambient atmosphere. Different nitrate/urea initial molar ratios were employed in order to investigate the influence of the reaction temperature in the physical characteristics of the powder composite. The flame temperature was measured by infrared optical pyrometer. The combustion was rapid and self-sustaining, with flame temperatures ranging from 870 to 1330°C. The as-synthesized powders were uniaxially pressed and sintered in air. Powders were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), helium picnometry for density measurements and gas adsorption technique (BET). The ceramic samples were evaluated by SEM and Archimedes density measurements.
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Jörgen Sandell and Mark Davies. "Benefits of sauna on lung capacity, neurocognitive diseases, and heart health." World Journal of Advanced Research and Reviews 17, no. 1 (January 30, 2023): 057–62. http://dx.doi.org/10.30574/wjarr.2023.17.1.1414.
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Sauna refers to passive heat therapy that involves exposure of the body to a high-temperature environment for an appropriately short period, contingent on the therapy’s purpose. Ideally, the therapy aims to raise the internal body temperature by a few degrees, and its effect happens in two phases. The first phase occurs during the first ten minutes, encouraging the body to perspire while maintaining a temperature of around 98.6 degrees. The extra heat is dispersed by increased blood circulation, blood pushing on the skin's surface, and sweating. The body enters the second phase after 10-30 minutes in the sauna. During this period, the body cannot disperse the sauna heat, thereby increasing the body temperature. In return, the heart rate and sweating increase. There are four different types of saunas. These include traditional saunas, usually heated with wood-burning stoves, rocks, or an electric coil. Far-infrared saunas are usually heated by metallic or ceramic elements that produce a small spectrum of light, referred to as far-infrared. Infrared lamp saunas are heated using heat lamps that produce radiant heat. The last type is steam saunas, traditionally heated, but water increases the humidity and air temperatures. During sauna therapy, the heart rate of an individual increase from the standard range up to 120 or 150 beats per minute. Unlike physical activity, sauna therapy does not involve any active function of the skeletal muscles. Even though skeletal muscles are inactive during a sauna session, blood volume is partially redirected to the internal organs' exterior body parts due to decreased venous return. Sauna therapy assists in liberating toxins piled in our tissues, facilitating lymph and blood circulation and strengthening one's immune system. Sauna bathing has mainly been used for purposes of relaxation and pleasure. Today, the activity is increasingly becoming popular as a form of treatment therapy. Several pieces of evidence claim that sauna bathing has numerous health benefits, including hemodynamic regulation processes, reduced risk of vascular diseases, cardiovascular disease, neurocognitive diseases, mortality, pulmonary diseases, stabilized arterial blood pressure, and enhancement of conditions such as flu, headache, and arthritis. However, response to stress from heat can increase muscle blood flow. This report will precisely explore the benefits of sauna bathing on lung capacity and heart health for people with cardiovascular, lung-related or respiratory-related, and neurocognitive diseases.
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Amore, Valentina, Malva I. M. Hernández, Luis M. Carrascal, and Jorge M. Lobo. "Exoskeleton may influence the internal body temperatures of Neotropical dung beetles (Col. Scarabaeinae)." PeerJ 5 (May 18, 2017): e3349. http://dx.doi.org/10.7717/peerj.3349.
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The insect exoskeleton is a multifunctional coat with a continuum of mechanical and structural properties constituting the barrier between electromagnetic waves and the internal body parts. This paper examines the ability of beetle exoskeleton to regulate internal body temperature considering its thermal permeability or isolation to simulated solar irradiance and infrared radiation. Seven Neotropical species of dung beetles (Coleoptera, Scarabaeinae) differing in colour, surface sculptures, size, sexual dimorphism, period of activity, guild category and altitudinal distribution were studied. Specimens were repeatedly subjected to heating trials under simulated solar irradiance and infrared radiation using a halogen neodymium bulb light with a balanced daylight spectrum and a ceramic infrared heat emitter. The volume of exoskeleton and its weight per volume unit were significantly more important for the heating rate at the beginning of the heating process than for the asymptotic maximum temperature reached at the end of the trials: larger beetles with relatively thicker exoskeletons heated more slowly. The source of radiation greatly influences the asymptotic temperature reached, but has a negligible effect in determining the rate of heat gain by beetles: they reached higher temperatures under artificial sunlight than under infrared radiation. Interspecific differences were negligible in the heating rate but had a large magnitude effect on the asymptotic temperature, only detectable under simulated sun irradiance. The fact that sun irradiance is differentially absorbed dorsally and transformed into heat among species opens the possibility that differences in dorsal exoskeleton would facilitate the heat gain under restrictive environmental temperatures below the preferred ones. The findings provided by this study support the important role played by the exoskeleton in the heating process of beetles, a cuticle able to act passively in the thermal control of body temperature without implying energetic costs and metabolic changes.
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Skripnyak, Vladimir V., and Vladimir A. Skripnyak. "Mechanical Behavior of Alpha Titanium Alloys at High Strain Rates, Elevated Temperature, and under Stress Triaxiality." Metals 12, no. 8 (August 2, 2022): 1300. http://dx.doi.org/10.3390/met12081300.
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The paper presents the experimental results of the mechanical behavior of Ti-5Al-2.5Sn alloy at high strain rates and elevated temperature. Flat smooth and notched specimens with notch radii of 10 mm, 5 mm, and 2.5 mm were used. The experimental studies were carried out using the high-velocity servo hydraulic test machine Instron VHS 40/50-20. The samples were heated with flat ceramic infrared emitters on average between 60 s and 160 s. The temperature control in the working part of specimens was carried out in real time using a chromel-alumel thermocouple. The digital image correlation (DIC) method was employed to investigate the evolution of local fields in the gauge section of the specimen. Data on the influence of stress triaxiality on the ductility of Ti-5Al-2.5Sn alloy were obtained under tension with strain rates ranging from 0.1 to 103 s−1 at a temperature of 673 K. It was found that, at 673 K, the ductility of Ti-5Al-2.5Sn alloy increases with the increasing strain rate for both smooth and notched specimens.
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Onoda, H., and R. Sasaki. "Preparation of novel blue phosphate pigments in imitation of turquoise." Cerâmica 65, no. 376 (December 2019): 641–44. http://dx.doi.org/10.1590/0366-69132019653762807.
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Abstract As a novel blue pigment, various hydrated copper aluminum phosphate imitating turquoise, CuAl6(PO4)4(OH)8.4H2O, were prepared by mixing copper nitrate solution, aluminum nitrate solution, phosphoric acid, and sodium hydroxide solution. Samples with similar chemical composition with turquoise were prepared. The obtained powders were evaluated with X-ray diffraction, infrared spectra, ultraviolet-visible reflectance spectra, and L*a*b* color space. Further, other related compositions were also investigated. Samples heated at low temperature were light blue powder. By heating at 700 ºC, the color of materials changed to deep green. Samples with high copper ratio indicated lower L* value and small a* and b* values. The low copper ratio was suitable to obtain light blue and deep green phosphate pigments.
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Donahue, Edward J., Michael Ng, and Patrick Li. "A determination of structural evolution during the processing of glycol-based, sol-gel derived ceramics through the study of ferrimagnetic interactions." Journal of Materials Research 22, no. 11 (November 2007): 3152–57. http://dx.doi.org/10.1557/jmr.2007.0395.
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This work studies the chemical and structural changes that occur in sols upon heating to form ceramics. Ferrimagnetic Y3Fe5O12 (YIG) was chosen because the geometric and structural constraint of ferrimagnetic interactions allow for a direct measurement of the degree of well-defined structure present within the sol at various stages of development. Glycolate sols of 8% mol total metal were prepared using Y(NO3)3 and Fe(NO3)3 hydrates in stoichiometric ratios. Terminal straight-chain diols were used, ranging from 1,2-ethanediol to 1,6-hexanediol. The temperatures at which mass change occurred during heating were determined by thermogravimetric analysis. Samples were heated to these temperatures and examined by Fourier transform infrared spectroscopy (FTIR), x-ray diffraction, and magnetometry to determine chemical, structural, and magnetic changes. Ferrimagnetic ordering was present after the first heating step. Defined structure, determined by x-ray, occurred in the penultimate step. Analysis of FTIR spectra, in conjunction with the results of thermogravimetric analysis, revealed a predictable decomposition pathway.
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Zhang, Gui-Yu, Sihwan Lee, Yi Han, and Xiao-Yong Wang. "The Effect of Oyster Shell Powder on the High-Temperature-Properties of Slag-Ceramic Powder-Based Geopolymer." Materials 16, no. 10 (May 13, 2023): 3706. http://dx.doi.org/10.3390/ma16103706.
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There is a lack of scientific understanding of adding an oyster shell powder (OSP) to geopolymer concrete. The purpose of this study is: (1) to evaluate the high-temperature resistance of the alkali-activated slag ceramic powder (CP) mixture added with OSP at different temperatures, (2) to address the lack of application of environmentally friendly building materials, and (3) to reduce solid waste of OSP pollution and protect the environment. OSP replaces granulated blast furnace slag (GBFS) and CP at 10% and 20% (based on binder), respectively. The mixture was heated to 400.0, 600.0, and 800.0 °C after curing for 180 days. The results of the experiment are summarized as follows: (1) The thermogravimetric (TG) results indicated that the OSP20 samples produced more CASH gels than the control OSP0. (2) As the temperature increased, the compressive strength and ultrasonic pulse velocity (UPV) both decreased. (3) Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results reveal that the mixture undergoes a phase transition at 800.0 °C, and compared with the control OSP0, OSP20 undergoes a different phase transition. (4) The size change and appearance image results indicate that the mixture with added OSP inhibits shrinkage, and calcium carbonate decomposes to produce off-white CaO. To sum up, adding OSP can effectively reduce the damage of high temperatures (800.0 °C) on the properties of alkali-activated binders.
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Barauskas, Rimantas, Audrone Sankauskaite, and Ausra Abraitiene. "Investigation of the thermal properties of spacer fabrics with bio-ceramic additives using the finite element model and experiment." Textile Research Journal 88, no. 3 (December 5, 2016): 293–311. http://dx.doi.org/10.1177/0040517516677228.
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The heat resistance of fabric enhanced by bio-ceramic additives (BCAs) is investigated theoretically and experimentally in order to determine the influence of modification of the infrared (IR) absorption property of the fabric. The enhanced IR sensitivity of textiles improves the thermoregulatory processes when worn in cold environments. The finite element model has been developed by taking into account the coupled phenomena of heat conduction, surface convection and the interaction of the fabric with IR power flux by employing heat transfer differential equations and the Stefan–Boltzmann law. Evaluations of IR absorptivity, reflectivity and transmissivity, the temperature transients during the hot plate chamber test and heat retaining properties of the fabric heated by an IR lamp have been obtained experimentally and simulated by means of the developed finite element model. The values of model parameters have been found, which provided a satisfactory match between the computation and the experiment in all considered cases. Simultaneously, the obtained values were reasonably close to rough theoretical estimations. Efforts have been made to distinguish from each other the influence of diffusive and radiative components of heat transfer, which affect the results of thermal resistance tests. The comparative analysis of contributions of different heat exchange mechanisms allows a better understanding of the peculiarities of standard heat resistance measurement procedures applied to BCA-enhanced fabrics and facilitates the validation of the computational models.
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Kaminski, D. A., and S. Kar. "Parametric Studies of a Spectrally Selective, Two-Layered, Porous, Volumetric Solar Collector." Journal of Solar Energy Engineering 114, no. 3 (August 1, 1992): 150–56. http://dx.doi.org/10.1115/1.2929998.
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A porous, packed bed, volumetric solar collector consisting of two dissimilar layers of spherical beads is numerically modeled. The bed is irradiated on the top surface by concentrated solar flux isotropic within a known cone angle. A gas stream perfusing the bed is heated by convection with the solid particles. The equation of radiative transfer, which accounts for absorption, emission, and linearly anisotropic scattering in the bed, is simplified by employing the P1 differential approximation. The bed materials are spectrally selective in the solar and infrared wavelengths. Sensitivity studies are used to identify the critical input parameters of the system, and a baseline configuration, which incorporates the key requirements of an efficient solar collector, is adopted. Parametric studies are conducted on the mass flow rate, incident solar flux, top layer porosity, solar absorptivity, particle diameter, and degree of back scatter. Tailoring of the particle and fluid temperature profiles and enhancing the efficiency of the collector by an appropriate selection of these critical parameters is demonstrated. Various high-temperature ceramics with suitable radiative properties are identified and their relative performance in the collector is assessed.
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Arrais, CAG, CL Chagas, A. Munhoz, M. Oliveira, AF Reis, and JA Rodrigues. "Effect of Simulated Tooth Temperature on the Degree of Conversion of Self-adhesive Resin Cements Exposed to Different Curing Conditions." Operative Dentistry 39, no. 2 (March 1, 2014): 204–12. http://dx.doi.org/10.2341/13-091-l.
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SUMMARY Objectives This study evaluated the degree of conversion (DC) of two commercial, self-adhesive resin cements (SARCs) using Fourier transform infrared analysis (FTIR) polymerized at simulated prepared tooth surface temperatures and under different curing conditions. Materials and Methods RelyX U100 (U100, 3M ESPE) and Maxcem Elite (MX, Kerr Corporation) were mixed at 25°C and applied to the surface of a horizontal attenuated total reflectance (ATR) unit, which was near room temperature (RT, control) (25°C) or heated to simulate prepared tooth surface temperatures (28°C and 32°C) and then attached to an infrared spectrometer. The products were polymerized using one of three conditions: direct light exposure through a glass slide (DLE), exposure through a 1.5-mm thick ceramic disc overlay (CO) (A2 shade, IPS e.max, Ivoclar Vivadent), or self-curing (SC). FTIR spectra were recorded for 12 minutes (1 spectrum/s, 16 scans/spectrum, resolution 4 cm−1) immediately after application to the ATR. The DC was calculated using standard techniques of observing changes in aliphatic-to-aromatic peak ratios before and 12 minutes after curing, as well as during each 1-second interval. DC data (n=7) were analyzed by two-way analysis of variance and Tukey's post-hoc test (p=0.05). Results Both simulated tooth temperatures significantly increased DC in all groups of MX and in the CO and SC groups of U100 compared with the RT control. For MX, the self-cure groups exposed to tooth temperatures showed DC values similar to those of the CO groups. For U100, the CO groups showed higher DC values than SC groups regardless of temperature. Time-based conversion profiles ranged according to product, temperature, and curing mode. Conclusions Causing SARCs to polymerize at simulated tooth temperatures increases DC of SARCs compared with room-temperature curing values, mainly in the SC mode.
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Zainal, Mustaffa, Ragunathan Santiagoo, Afizah Ayob, Azlinda Abdul Ghani, Wan Azani Mustafa, and Nurul Syazwani Othman. "Thermal and mechanical properties of chemical modification on sugarcane bagasse mixed with polypropylene and recycle acrylonitrile butadiene rubber composite." Journal of Thermoplastic Composite Materials 33, no. 11 (April 8, 2019): 1533–54. http://dx.doi.org/10.1177/0892705719832072.
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The goal of this research is to investigate the thermal, chemical, and tensile properties of chemical modification of sugarcane bagasse (SCB)-filled polypropylene (PP) and recycled acrylonitrile butadiene rubber (NBRr). The composites with different SCB loading (5, 15, and 30 per hundred resin) were prepared using a heated two-roll mill at temperature of 180°C.Thermal and the tensile properties of the modified SCB composite have shown improvement. The silane-treated composites have higher thermal stability compared to treated NaOH. The degradation temperature at 70% weight ( T 70%) of NaOH and silane composite increase by 6% and 15%, respectively. Meanwhile, the tensile strength and Young’s modulus for the both treatment showed an improvement of 20% and 25% for NaOH and 30% and 32% for silane compared to untreated composites, respectively. The chemical properties were investigated using Fourier transform infrared analysis. The modification SCB fiber has improved the adhesion and interfacial bonding between SCB fiber and PP/NBRr matrices.
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Al Khasawneh, Sahar, Andrew S. Murray, Stephen Bourke, and Dominik Bonatz. "Testing feldspar luminescence dating of young archaeological heated materials using potshards from Pella (Tell Tabqat Fahl) in the Jordan valley." Geochronometria 44, no. 1 (May 2, 2017): 98–110. http://dx.doi.org/10.1515/geochr-2015-0056.
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Abstract Recent developments in the use of more stable feldspar signals in the luminescence dating of sediments offer the possibility of obtaining accurate feldspar luminescence ages for ceramic artefacts; this is especially interesting in locations which do not provide suitable quartz extracts. Here we examine the application of the stable infrared stimulated luminescence signal measured at elevated temperature (in this case 290°C; pIRIR290) after stimulation at about room temperature to Levantine pottery samples. A total of 52 potsherds were collected from three superimposed iron-age units at Pella (Jordan); based on 14C dating, typology and seriation these units were deposited between 700 and 900 BCE. Sand-sized quartz extracts were unsuitable, and there was insufficient sand-sized feldspar, and so polymineral fine grains were chosen for dating. Various tests for reliability were undertaken (dose recovery, dependence of De on first stimulation temperature etc.). The pIRIR signals are weak, and 14 potsherds were rejected on this basis. Of the remainder, 3 were confidently identified as outliers. Based on those sherds for which IR signals were sufficiently intense, we use the ratio of the IR50 to pIRIR290 signals to argue that these outliers do not arise from incomplete resetting during manufacture. The ages from each layer are considerably over dispersed (typically by ∼25%) but average ages for each unit are consistent with each other and with the expected age range. The average OSL age for the site is 2840 ± 220 years (n = 35), with the overall uncertainty dominated by systematic uncertainties; this average is consistent with the range of 14C ages from 970–1270 BCE reported from across the destruction horizon. We conclude that the pIRIR290 signal is delivering accurate ages, but that the variability in age from shard to shard is much greater than would be expected from known sources of uncertainty. This demonstrates the need for site ages to be based on multiple samples; individual shard ages are unlikely to be sufficiently accurate.
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Swanson, D., and J. Wolfrum. "Time to failure modeling of carbon fiber reinforced polymer composites subject to simultaneous tension and one-sided heat flux." Journal of Composite Materials 52, no. 18 (February 5, 2018): 2503–14. http://dx.doi.org/10.1177/0021998317749711.
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This study focuses on observing and analyzing the time to failure of carbon fiber reinforced polymers subject to mechanical loading and one-sided heat flux simulating fire damage. The purpose of this investigation is to understand the rate of thermal degradation and mechanical property loss from fire exposure, resulting in catastrophic failure under simultaneous tensile loading. Composite samples of varying thicknesses and layup patterns are subject to a constant tensile load below the ultimate strength of the material. A thermal load is applied to one side by an infrared band heater, emitting a constant heat flux. The time to failure is monitored to determine how long the material can withstand this combined loading condition. A consistent trend is observed for various heat flux settings. High mechanical loads contribute to a shorter time to failure, and low mechanical loads contribute to a longer time to failure. Similarly, higher heat flux settings result in shorter failure times, and lower heat flux settings result in longer failure times. Temperature profiles are created based on heat flux exposure time and position through the sample thickness, establishing failure criteria for different loading conditions. The resulting trends are observed and extrapolated to create a predictive model using an Arrhenius exponential decay function.
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Tönbül, Beyza, Hilal A. Can, Tayfur Öztürk, and Hasan Akyıldız. "Solution processed glass/fluorine-doped tin oxide/aluminum-doped zinc oxide double layer thin films for transparent heater and near-infrared reflecting applications." Journal of Sol-Gel Science and Technology 99, no. 3 (August 11, 2021): 482–96. http://dx.doi.org/10.1007/s10971-021-05591-1.
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Saltan, Fehmi, Hakan Akat, and Fatih Sefa Arıkan. "Synthesis, characterization, and thermal degradation kinetics of poly(styrene-co-N-maleimide isobutyl polyhedral oligosilsesquioxane)." Journal of Thermoplastic Composite Materials 30, no. 4 (August 3, 2016): 490–503. http://dx.doi.org/10.1177/0892705715604676.
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This study demonstrated that poly(styrene- co- N-maleimide isobutyl polyhedral oligosilsesquioxane (POSS)) (P(S- co-NMIP)) was successfully prepared using free radical polymerization. For this purpose, firstly, N-maleimide isobutyl POSS (NMIP) was synthesized using aminopropyllsobutyl POSS (POSS-NH2) and maleic anhydride. Secondly, P(S- co-NMIP) was synthesized using styrene, NMIP, and 2,2-azobis(isobutyronitrile) as initiator in tetrahydrofuran for 24 h at 75°C to give copolymer. The synthesized polymer and compounds were characterized by proton nuclear magnetic resonance, gel permeation chromatography, and Fourier transform infrared spectroscopy. Thermal behaviors of P(S- co-NMIP) were analyzed using thermogravimetric and differential scanning calorimetric analyses. The apparent activation energies ( Es) for thermal degradation of P(S- co-NMIP) were obtained by integral methods (Flynn–Wall–Ozawa (FWO) and Kissinger). P(S- co-NMIP) was heated thermogravimetrically under various heating rates such as 5, 10, 15, and 20°C min−1 at a temperature range of 30–1000°C to determine their thermal degradation mechanisms. The values of E for P(S- co-NMIP) were found to be 127.5 ± 2.3 and 134.4 ± 14.8 kJ mol−1 for FWO and Kissinger methods, respectively. Also, the values of E of synthesized copolymer (P(S- co-NMIP)) were compared with styrene- co-maleic anhydride copolymer in literature.
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Cheng, Liangliang, Zongfei Tong, Shejuan Xie, and Mathias Kersemans. "IRT-GAN: A generative adversarial network with a multi-headed fusion strategy for automated defect detection in composites using infrared thermography." Composite Structures 290 (June 2022): 115543. http://dx.doi.org/10.1016/j.compstruct.2022.115543.
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Malecha, Karol. "The utilization of LTCC-PDMS bonding technology for microfluidic system applications – a simple fluorescent sensor." Microelectronics International 33, no. 3 (August 1, 2016): 141–48. http://dx.doi.org/10.1108/mi-03-2016-0027.
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Purpose This paper aims to present a research on utilization of an irreversible bonding between non-transparent low temperature co-fired ceramics (LTCC) and transparent poly(dimethylsiloxane) (PDMS). The research presented in this paper is focused on the technology and performance of the miniature microfluidic module for fluorescence measurement. Design/methodology/approach The chemical combination of both materials is achieved through surface modification using argon-oxygen dielectric barrier discharge (DBD) plasma. According to the performed spectroscopic analyses (X-ray photoelectron spectroscopy, XPS; attenuated total reflection-Fourier infrared spectroscopy, ATR-FTIR) and contact angle measurements, the LTCC and PDMS surfaces are oxidized during the process. The presented microfluidic module was fabricated using LTCC technology. The possibility for the fabrication of LTCC-PDMS microfluidic fluorescent sensor is studied. The performance of the sensor was examined experimentally. Findings As a result of DBD plasma oxidation, the LTCC and PDMS surfaces change in character from hydrophobic to hydrophilic and were permanently bonded. The presented LTCC-PDMS bonding technique was used to fabricate a microfluidic fluorescent sensor. The preliminary measurements of the sensor have proven that it is possible to observe the fluorescence of a liquid sample from a very small volume. Research limitations/implications The presented research is a preliminary work which is focused on the fabrication of the LTCC-PDMS fluorescent sensor. The microfluidic device was positively tested only for ethanolic fluorescein solutions. Therefore, fluorescence measurements should be performed for biological specimen (e.g. DNA). Practical implications The LTCC-PDMS bonding technology combines the advantages of both materials. One the one hand, transparent PDMS with precise, transparent three-dimensional structures can be fabricated using hot embossing, soft lithography or laser ablation. On the other hand, rigid LTCC substrate consisting of microfluidic structures, electric interconnections, heaters and optoelectronic components can be fabricated. The development of the LTCC-PDMS microfluidic modules provides opportunity for the construction of a lab-on-chip, or micro-total analysis systems-type system, for analytical chemistry and fast medical diagnoses. Originality/value This paper shows utilization of the PDMS-LTCC bonding technology for microfluidics. Moreover, the design, fabrication and performance of the PDMS-LTCC fluorescent sensor are presented.
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Gupta, Ranjeetkumar, James Njuguna, and Ketan Pancholi. "Optimising Crystallisation during Rapid Prototyping of Fe3O4-PA6 Polymer Nanocomposite Component." Journal of Composites Science 6, no. 3 (March 7, 2022): 83. http://dx.doi.org/10.3390/jcs6030083.
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Polymer components capable of self-healing can rapidly be manufactured by injecting the monomer (ε-caprolactam), activator and catalyst mixed with a small amount of magnetic nanoparticles into a steel mould. The anionic polymerisation of the monomer produces a polymer component capturing magnetic nanoparticles in a dispersed state. Any microcracks developed in this nanocomposite component can be healed by exposing it to an external alternating magnetic field. Due to the magnetocaloric effect, the nanoparticles locally melt the polymer in response to the magnetic field and fill the cracks, but the nanoparticles require establishing a network within the matrix of the polymer through effective dispersion for functional and uniform melting. The dispersed nanoparticles, however, affect the degree of crystallinity of the polymer depending on the radius of gyration of the polymer chain and the diameter of the magnetic nanoparticle agglomerates. The variation in the degree of crystallinity and crystallite size induced by nanoparticles can affect the melting temperature as well as its mechanical strength after testing for applications, such as stimuli-based self-healing. In the case of in situ synthesis of the polyamide-6 (PA6) magnetic nanocomposite (PMC), there is an opportunity to alter the degree of crystallinity and crystallite size by optimising the catalyst and activator concentration in the monomer. This optimisation method offers an opportunity to tune the crystallinity and, thus, the properties of PMC, which otherwise can be affected by the addition of nanoparticles. To study the effect of the concentration of the catalyst and activator on thermal properties, the degree of crystallinity and the crystallite size of the component (PMC), the ratio of activator and catalyst is varied during the anionic polymerisation of ε-caprolactam, but the concentration of Fe3O4 nanoparticles is kept constant at 1 wt%. Differential Scanning Calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), XRD (X-ray diffraction) and Thermogravimetric analysis (TGA) were used to find the required concentration of the activator and catalyst for optimum properties. It was observed that the sample with 30% N-acetyl caprolactam (NACL) (with 50% EtMgBr) among all of the samples was most suitable to Rapid Prototype the PMC dog-bone sample with the desired degree of crystallinity and required formability.
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Gao, Xiang, Matt von Boecklin, Ivan Ermanoski, and Ellen B. Stechel. "Low-Cost Radiant Heater for Rapid Response, High-Temperature Heating." Frontiers in Energy Research 9 (April 21, 2021). http://dx.doi.org/10.3389/fenrg.2021.652203.
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High-temperature processing has an irreplaceable role in many research and industrial applications. Despite remarkable development spanning over a century, the pursuit of even higher thermal flux density and more rapid thermal transients has not slowed down. As part of the ongoing energy evolution, many industrial applications are transitioning from direct combustion of fossil fuels as primary energy sources to increasing electrification, capable of adapting to renewable power grids. Thus, there is an emerging need for electrical heaters that can replace burners and supply the heat demand, especially at the highest temperatures. In this study, we report on a radiant heater design that can achieve cyclic heating/cooling rates of up to 400 K min–1 and a temperature range in excess of 1,800 K, comparable to those of commercial infrared gold image furnaces, at high surface and volumetric power densities. The heater consists of a modular unit of incandescent tungsten filament and is enclosed in an evacuated ceramic envelope, chemically inert, tolerant of thermal shock, and impervious to gasses. The material and manufacture cost of such heaters, which is estimated at ∼$0.05/W, is less than 0.03% of that for infrared gold image furnaces, which is at >$2/W. Tests of more than 10,000 demanding cycles (high temperature and high heating/cooling rate) over 350 h of total operational time and in different temperature ranges confirm the robust performance of radiant heater prototypes. The design is widely applicable to high-temperature reactor and furnace designs. In thermochemistry research and practice, these radiant heaters could offer multiple benefits compared to solar simulators, lasers, infrared gold furnaces, ceramic heaters, or direct concentration of solar input.
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"5494003 Water heater with perforated ceramic plate infrared burner." Journal of Cleaner Production 4, no. 1 (January 1996): 81–82. http://dx.doi.org/10.1016/s0959-6526(96)80210-1.
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Lebel, Larry, Sylvain Turenne, and Rachid Boukhili. "An Experimental Apparatus and Procedure for the Simulation of Thermal Stresses in Gas Turbine Combustion Chamber Panels Made of Ceramic Matrix Composites." Journal of Engineering for Gas Turbines and Power 139, no. 9 (April 11, 2017). http://dx.doi.org/10.1115/1.4035906.
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This paper presents an experimental procedure developed to simulate the behavior of ceramic matrix composites (CMCs) under the cyclic thermal stresses of a gas turbine combustion chamber. An experimental apparatus was assembled that produces a temperature gradient across the thickness of a CMC specimen while holding the specimen at its two extremities, which simulates the bending stress that would be observed at the center of a combustor panel. Preliminary validation tests were performed in which A-N720 oxide–oxide CMC specimens were heated to a surface temperature of up to 1160 °C using an infrared heater, which allowed for the calibration of heat losses and material thermal conductivity. The specimen test conditions were compared with predicted conditions in generic annular combustor panels made of the same material. Provided that a more powerful heat source is made available to reach sufficiently high temperatures and through-thickness temperature gradients simultaneously, the proposed experiment promises to allow laboratory observation of representative deterioration modes of a CMC inside an actual combustion chamber.
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Zhu, Mengya, Guangyong Li, Wenbin Gong, Lifeng Yan, and Xuetong Zhang. "Calcium-Doped Boron Nitride Aerogel Enables Infrared Stealth at High Temperature Up to 1300 °C." Nano-Micro Letters 14, no. 1 (December 6, 2021). http://dx.doi.org/10.1007/s40820-021-00754-9.
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AbstractBoron nitride (BN) aerogels, composed of nanoscale BN building units together with plenty of air in between these nanoscale building units, are ultralight ceramic materials with excellent thermal/electrical insulation, great chemical stability and high-temperature oxidation resistance, which offer considerable advantages for various applications under extreme conditions. However, previous BN aerogels cannot resist high temperature above 900 °C in air atmosphere, and high-temperature oxidation resistance enhancement for BN aerogels is still a great challenge. Herein, a calcium-doped BN (Ca-BN) aerogel with enhanced high-temperature stability (up to ~ 1300 °C in air) was synthesized by introducing Ca atoms into crystal structure of BN building blocks via high-temperature reaction between calcium phosphate and melamine diborate architecture. Such Ca-BN aerogels could resist the burning of butane flame (~ 1300 °C) and keep their megashape and microstructure very well. Furthermore, Ca-BN aerogel serves as thermal insulation layer, together with Al foil serving as both low-infrared-emission layer and high-infrared-reflection layer, forming a combination structure that can effectively hide high-temperature target (heated by butane flame). Such successful chemical doping of metal element into crystal structure of BN may be helpful in the future design and fabrication of advanced BN aerogel materials, and further extending their possible applications to extremely high-temperature environments.
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С, Саран, Тэнгис С, Оргил Б, Мөнхтулга Р, and Хублин Ж. Ж. "Полиминералын post IR болон кварцын кристаллын люминесценцийн аргыг хослуулан олдворын он цагийг тогтоох нь." Proceedings of the Mongolian Academy of Sciences, July 7, 2017, 42–51. http://dx.doi.org/10.5564/pmas.v53i207.828.
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Given the need to date the series of unknown burials at the site Khutag Uul, Arkhangai province (Mongolia), different luminescence dating methods were applied: p-IRIR (IR at lower temperature and post infrared stimulation at an elevated temperature) and SGL (single grain luminescence) on both heated ceramics consisting of fine grains of quartz and feldspar and unheated coarse quartz from surrounding sediments. Detailed study has been done in order to analyze the composition of the IR and p-IRIR decay curves which suggest that the equivalent doses obtained from the IR50 and IR at elevated temperature might originate from one trap. Experimental results of IR, p-IRIR suggest a date 3±75BC and 203±95BC, respectively; the single grain (SG) luminescence measurements yield a date 198±94BC for the production of pottery. The surrounding sediment material, which was originally used for the determination of the dose-rate, was an mixed population with an indication that a grave was robbed around 588±70AD.
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Solanki, Pushpkant, Mahatta Oza, Girish Joshi, H. O. Jethwa, and Mihir Joshi. "Synthesis, Structural, FT-IR, UV-Vis. Spectroscopic, Thermal, and BET Studies of Magnesium Ion Doped Strontium Pyrophosphate Nano-Particles." ECS Journal of Solid State Science and Technology, February 16, 2023. http://dx.doi.org/10.1149/2162-8777/acbc98.
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Abstract Pyrophosphates are very useful as bioactive ceramics; in particular, calcium pyrophosphate has made impressive progress as biocompatible material promoting tissue formation. 2% Mg, 5% Mg, and 10% Mg ion doped SrPPi nano-particles are synthesized using a surfactant-mediated approach. The powder X-ray diffraction pattern confirms the tetragonal structure of materials and nano-structured in nature. Transmission electron microscopy study confirmed the nano-size and the dimensions in the range from 7.46 to 51.70 nm. P-O-P and PO3 have both symmetric and asymmetric stretching vibrations, according to the Fourier transform infrared (FT-IR) spectroscopy investigation. The direct optical energy band gap for 2% Mg, 5% Mg, and 10% Mg ion doped Sr2P2O7 samples is found to be 4.98, 4.75, and 4.55 eV using UV-nuclear imaging resonance absorption spectroscopy spanning the spectral range of 210-1200 nm. EDAX analysis confirmed the elemental presence. Thermogravimetric analysis proved that the sample included water molecules. According to thermogravimetric analysis, the samples become anhydrous and almost remain stable when heated over 600–1000°C. Photoluminescence study is indicating the emission in the visible range. Brunnauer-Emmett-Teller (BET) analysis gives information on surface area and pore size.
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Popp, Julian, Tobias Kleffel, David Römisch, Thomas Papke, Marion Merklein, and Dietmar Drummer. "Fiber Orientation Mechanism of Continuous Fiber Reinforced Thermoplastics Hybrid Parts Joined with Metallic Pins." Applied Composite Materials, April 17, 2021. http://dx.doi.org/10.1007/s10443-021-09892-0.
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AbstractContinuous Fiber Reinforced Thermoplastic (CFRT) hybrid parts offer interesting possibilities for lightweight application, which can exceed the capabilities of mono material metal or CFRT parts. In this case, the joining technology oftentimes is the limiting factor. This study investigates a joining operation with metal pin structures which are additively manufactured via powder bed fusion featuring different diameters and tip geometries, which are inserted into the locally infrared heated CFRT part. The resulting fiber rearrangement is assessed using transmitted light microscopy, confocal laser scanning microscopy as well as micro-computer-tomography. It could be shown that for all assessed pin variants a similar distinct fiber displacement can be seen and that the pin diameter has a significant effect on the resulting fiber orientation with smaller pin diameters being advantageous because of gentle fiber displacement and reduced undulation. The tip geometry has only minor effect on the fiber orientation. Especially in the X/Y plane no systematic influence of the tip geometry on the fiber displacement could be observed. Based on the gained insights a three-stage model of the fiber orientation processes is proposed.
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Myers, Philip D., D. Yogi Goswami, and Elias Stefanakos. "Molten Salt Spectroscopy for Quantification of Radiative Absorption in Novel Metal Chloride-Enhanced Thermal Storage Media." Journal of Solar Energy Engineering 137, no. 4 (March 17, 2015). http://dx.doi.org/10.1115/1.4029934.
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This study describes the development and characterization of novel high-temperature thermal storage media, based on inclusion of transition metal chlorides in the potassium–sodium chloride eutectic system, (K–Na)Cl (melting temperature of 657 °C, latent heat of 278 J/g). At the melting temperature of (K–Na)Cl, infrared (IR) radiation can play a major role in the overall heat transfer process—90% of spectral blackbody radiation falls in the range of 2–13 μm. The authors propose inclusion of small amounts (less than 0.2 wt.%) of IR-active transition metal chlorides to increase radiative absorption and thereby enhance heat transfer rates. A new IR-reflectance apparatus was developed to allow for determination of the spectral absorption coefficient of the newly formulated phase-change materials (PCMs) in the molten state. The apparatus consisted of an alumina crucible coated at the bottom with a reflective (platinum) or absorptive (graphite) surface, a heated ceramic crucible-holder, and a combination of zinc sulfide (ZnS) and zinc selenide (ZnSe) windows for containment of the salt and allowance of inert purge gas flow. Using this apparatus, IR spectra were obtained for various transition metal chloride additives in (K–Na)Cl and improved IR activity, and radiative transfer properties were quantified. Further, thermophysical properties relevant to thermal energy storage (i.e., melting temperature and latent heat) are measured for the pure and additive-enhanced thermal storage media.
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Bibinger, Johannes, Sebastian Eibl, and Hans-Joachim Gudladt. "Influence of Low and Extreme Heat Fluxes on Thermal Degradation of Carbon Fibre-reinforced Polymers." Applied Composite Materials, June 24, 2022. http://dx.doi.org/10.1007/s10443-022-10043-2.
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AbstractThis study considers the influence of different irradiation scenarios on the thermal degradation of carbon fibre-reinforced polymers (CFRP). Real threats are simulated, such as fires with long-lasting low heat fluxes and nuclear heat flashes with short-lasting high heat fluxes. For this purpose, coated and uncoated quasi-isotropic samples of the commercially available CFRP HexPly® 8552/IM7 are thermally irradiated from one side by an electrical heater of a cone calorimeter and a xenon short-arc lamp of a laboratory heat flash simulator with heat fluxes between 5 and 175 W/cm2 at varying time intervals. The specimens’ temperature is recorded on the front and back side as well as at different laminate depths. The CFRP are analyzed with ultrasonic testing (UT), infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM) and micro-focused computed X-Ray tomography (μCT). Destructive tests are performed to determine the mechanical properties in terms of interlaminar shear, compressive and tensile strength. When samples of CFRP are exposed to higher heat flux, high temperatures and temperature gradient values occur along the cross-section. As a result, extreme damage gradients appear in the material, leading to changes in damage behavior and loss of mechanical properties within seconds. However, to ensure the safety of the material in case of thermal exposure, loading limits are introduced, indicating the threshold for strength collapse. In addition, with the application of coatings, thermal degradation of CFRP can be delayed. Finally, the time-heat flux superposition principle is established to predict the residual strength under different loading scenarios.
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Simões, Carlos D., and Vera Aldeias. "Thermo-microstratigraphy of shells reveals invisible fire use and possible cooking in the archaeological record." Frontiers in Earth Science 10 (September 1, 2022). http://dx.doi.org/10.3389/feart.2022.869487.
Full textAbstract:
The archaeological visibility of hearths related to shellfish cooking methods is limited, particularly in pre-ceramic shell midden contexts. Important evidence for use of fire is the thermal alteration of components, namely the identification of burnt shells. Mollusk shells that mineralize as aragonite are particularly indicative of burning due to the conversion of aragonite to calcite through recrystallization at known temperature thresholds. However, roasting temperatures needed to open bivalves, do not necessarily cause thermal alterations in the cooked shell. This complicates the significance of shell mineralogy by itself to recognize cooking, and discerning pre-depositional from in situ heating. To distinguish between cooking and burning, we combine micromorphological analyses with microscopic Fourier transformed infrared spectroscopy to investigate mineralogical thermo-alterations alongside microstratigraphic formation studies. Experimentally heated specimens of Cerastoderma edule and Scrobicularia plana are used to identify the temperature thresholds of biogenic calcium carbonate phase alteration at the micro-scale. These results are then used to interpret mineral alterations in deposits from two Mesolithic shell midden contexts from Portugal. Micro-stratigraphically controlled mineralogy proved to be particularly useful to distinguish between pre-depositional heating from in situ heating, configuring a novel methodology for recognition of traces of cooking shellfish versus traces of fire used for other purposes. Mapping the mineral phase conversion at a micro stratigraphic scale also allows us to identify instances of in situ fire events that were invisible macroscopically. This combined microstratigraphic and mineralogical methodology considerably increases our capacity of deciphering intricate shell midden stratigraphy and occupational events.
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Schuster, Thomas J., Lars Weller, Johannes Wolfrum, and Sebastian Eibl. "Silver nanoparticle modified carbon fiber-reinforced polymer material for resistance against thermal damage induced by irradiation." Journal of Composite Materials, October 26, 2020, 002199832096890. http://dx.doi.org/10.1177/0021998320968908.
Full textAbstract:
We investigated the resistance of carbon fiber-reinforced plastics (CFRP) to thermal radiation when silver nanoparticles are added to the resin. An epoxy based CFRP material filled with up to 10 wt.% silver nanoparticles, with respect to the polymer matrix, shows an increase in time to ignition of up to ∼ 30% when irradiated from one side with an electrical heater with heat fluxes of 35 and 80 kW/m2. Scattering and specular reflectance of infrared light was analyzed before thermal irradiation, showing enhanced scattering of samples with increasing silver particle content, which correlates linearly to the time to ignition. The reaction to fire properties of the CFRP, analyzed by cone calorimetry, are also influenced positively by the silver nanoparticles. The thermal conductivity, as measured by laser-flash-analysis, shows no influence by the nanoparticles. Therefore, the increase in time to ignition, as well as the more homogeneous combustion, are not due to changes in conductivity, but to scattering and reflection effects caused by the nanoparticles. The modified material shows no decline in interlaminar shear strength, representing structural properties. Health and environmental risks by nanoparticle release during production, combustion, and machining of the modified CFRP are also investigated. The preliminary results show no additional hazards.
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Green, Danielle, Fereidoun Rezanezhad, Sean Jordan, Claudia Wagner-Riddle, Hugh A. L. Henry, Stephanie Slowinski, and Philippe Van Cappellen. "Effects of winter pulsed warming and snowmelt on soil nitrogen cycling in agricultural soils: A lysimeter study." Frontiers in Environmental Science 10 (October 12, 2022). http://dx.doi.org/10.3389/fenvs.2022.1020099.
Full textAbstract:
In cold regions, climate change is expected to result in warmer winter temperatures and increased temperature variability. Coupled with changing precipitation regimes, these changes can decrease soil insulation by reducing snow cover, exposing soils to colder temperatures and more frequent and extensive soil freezing and thawing. Freeze-thaw events can exert an important control over winter soil processes and the cycling of nitrogen (N), with consequences for soil health, nitrous oxide (N2O) emissions, and nearby water quality. These impacts are especially important for agricultural soils and practices in cold regions. We conducted a lysimeter experiment to assess the effects of winter pulsed warming, soil texture, and snow cover on N cycling in agricultural soils. We monitored the subsurface soil temperature, moisture, and porewater geochemistry together with air temperature, precipitation, and N2O fluxes in four agricultural field-controlled lysimeter systems (surface area of 1 m2 and depth of 1.5 m) at the University of Guelph’s Elora Research Station over one winter (December 2020 to April 2021). The lysimeters featured two soil types (loamy sand and silt loam) which were managed under a corn-soybean-wheat rotation with cover crops. Additionally, ceramic infrared heaters located above two of the lysimeters were turned on after each snowfall event to melt the snow and then turned off to mimic snow-free winter conditions with increased soil freezing. Porewater samples collected from five depths in the lysimeters were analyzed for total dissolved nitrogen (TDN), nitrate (NO3−), nitrite (NO2−), and ammonium (NH4+). N2O fluxes were measured using automated soil gas chambers installed on each lysimeter. The results from the snow removed lysimeters were compared to those of lysimeters without heaters (with snow). As expected, the removal of the insulating snow cover resulted in more intense soil freeze-thaw events, causing increased dissolved N loss from the lysimeter systems as N2O (from the silt loam system) and via NO3− leaching (from the loamy sand system). In the silt loam lysimeter, we attribute the freeze thaw-enhanced N2O fluxes to de novo processes rather than gas build up and release. In the loamy sand lysimeter, we attribute the increased NO3− leaching to the larger pore size and therefore lower water retention capacity of this soil type. Overall, our study illustrates the important role of winter snow cover dynamics and soil freezing in modulating the coupled responses of soil moisture, temperature, and N cycling.