scholarly journals Novel Multilayer SAW Temperature Sensor for Ultra-High Temperature Environments

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 643
Author(s):  
Xuhang Zhou ◽  
Qiulin Tan ◽  
Xiaorui Liang ◽  
Baimao Lin ◽  
Tao Guo ◽  
...  
Keyword(s):  
High Temperature ◽  
Temperature Sensor ◽  
X Ray Diffraction ◽  
Aero Engine ◽  
Before And After ◽  
Application Potential ◽  
Passive Sensors ◽  
Temperature Exposure ◽  
Engine Systems

Performing high-temperature measurements on the rotating parts of aero-engine systems requires wireless passive sensors. Surface acoustic wave (SAW) sensors can measure high temperatures wirelessly, making them ideal for extreme situations where wired sensors are not applicable. This study reports a new SAW temperature sensor based on a langasite (LGS) substrate that can perform measurements in environments with temperatures as high as 1300 °C. The Pt electrode and LGS substrate were protected by an AlN passivation layer deposited via a pulsed laser, thereby improving the crystallization quality of the Pt film, with the function and stability of the SAW device guaranteed at 1100 °C. The linear relationship between the resonant frequency and temperature is verified by various high-temperature radio-frequency (RF) tests. Changes in sample microstructure before and after high-temperature exposure are analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The analysis confirms that the proposed AlN/Pt/Cr thin-film electrode has great application potential in high-temperature SAW sensors.

Improvement of the Crystalline Quality of β-Ga2O3 Films by High-Temperature Annealing

2012 ◽  
Vol 725 ◽  
pp. 273-276
Author(s):  
Motoki Takahara ◽  
Suguru Funasaki ◽  
Jyun Kudou ◽  
Isao Tsunoda ◽  
Kenichiro Takakura ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Crystalline Quality ◽  
High Temperature Annealing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Si Doped ◽  
Scanning Electron

For the purpose of improving the crystalline quality of undoped and Si doped β-Ga2O3 films, high temperature annealing at 900°C was performed. The crystalline quality of the films investigated using scanning electron microscopy and X-ray diffraction. Also the conductivity of the films is compared before and after the annealing. After the 900°C annealing, the XRD peaks intensity corresponding to β-Ga2O3 is increased. This result indicates that the crystalline quality improves by the high temperature annealing.

scholarly journals X-ray diffraction analysis of kaolin M1 and M2 via the Williamson–Hall and Warren–Averbach methods

2021 ◽  
pp. 174751982098472
Author(s):  
Lalmi Khier ◽  
Lakel Abdelghani ◽  
Belahssen Okba ◽  
Djamel Maouche ◽  
Lakel Said
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Low Temperature ◽  
Diffraction Analysis ◽  
Mechanical Resistance ◽  
X Ray Diffraction ◽  
Integral Breadth ◽  
X Ray ◽  
Mullite Phase

Kaolin M1 and M2 studied by X-ray diffraction focus on the mullite phase, which is the main phase present in both products. The Williamson–Hall and Warren–Averbach methods for determining the crystallite size and microstrains of integral breadth β are calculated by the FullProf program. The integral breadth ( β) is a mixture resulting from the microstrains and size effect, so this should be taken into account during the calculation. The Williamson–Hall chart determines whether the sample is affected by grain size or microstrain. It appears very clearly that the principal phase of the various sintered kaolins, mullite, is free from internal microstrains. It is the case of the mixtures fritted at low temperature (1200 °C) during 1 h and also the case of the mixtures of the type chamotte cooks with 1350 °C during very long times (several weeks). This result is very significant as it gives an element of explanation to a very significant quality of mullite: its mechanical resistance during uses at high temperature remains.

Influence of high-temperature exposure on sugar content and chipping quality of potatoes

1968 ◽  
Vol 45 (10) ◽  
pp. 359-365 ◽  
Author(s):  
Herman Timm ◽  
M. Yamaguchi ◽  
M. D. Clegg ◽  
J. C. Bishop
Keyword(s):  
High Temperature ◽  
Sugar Content ◽  
High Temperature Exposure ◽  
Temperature Exposure ◽  
Chipping Quality

Annealing Time Dependence on 1.5μm Photoluminescence of Laser-Ablated β-FeSi2

2005 ◽  
Vol 891 ◽  
Author(s):  
Shin-ichiro Uekusa ◽  
Kunitoshi Aoki ◽  
Mohammad Zakir Hossain ◽  
Tomohiro Fukuda ◽  
Noboru Miura
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Thermal Diffusion ◽  
Annealing Time ◽  
Crystal Quality ◽  
Photoluminescence Intensity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Long Time

ABSTRACTWe prepared β-FeSi2 thin-films by using a Pulsed Laser Deposition (PLD) method and succeeded to observe photoluminescence (PL) around 1.5 μm corresponding to β-FeSi2 band from the long-time and high-temperature annealed β-FeSi2 thin-films. The β-FeSi2 thin-films were ablated on Si(111) substrates heated at 550°C. After ablation, long-time and high-temperature thermal annealing was performed in order to improve the crystal-quality. Annealing times were 5, 10, 20 and 40 hrs, and annealing temperature was kept at 900 °C. Crystallinity was evaluated by an X-ray diffraction (XRD) measurement. We have observed eminent improvement on crystal-quality of β-FeSi2 thin-films. Annealed samples show (220) or (202) X-ray diffraction signals of β-FeSi2 and the full width at half maximum (FWHM) of these peaks were 0.27° although the thickness of the samples decreased with annealing time. Thermal-diffusion of Si atoms was observed from substrate to thin-films. Fe atoms in the ablated thin-films also diffused into the substrate. The relationship between the thickness of β-FeSi2 thin-films and the thermal-diffusion were investigated with rutherford backscattering (RBS) measurement. Maximum photoluminescence intensity around 1.5 μm was observed from the thickest β-FeSi2 thin-film with only 5 hrs annealing.

scholarly journals Low-Power Laser Graphitization of High Pressure—High Temperature Nanodiamond Films

2020 ◽  
Vol 10 (9) ◽  
pp. 3329
Author(s):  
Konstantin G. Mikheev ◽  
Tatyana N. Mogileva ◽  
Arseniy E. Fateev ◽  
Nicholas A. Nunn ◽  
Olga A. Shenderova ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Laser Excitation ◽  
X Ray Diffraction ◽  
Power Laser ◽  
Green Luminescence ◽  
X Ray ◽  
Atomic Force ◽  
High Pressure High Temperature ◽  
Before And After

Laser-induced graphitization of 100 nm monocrystals of diamond particles synthesized by high-pressure high-temperature (HP-HT) methods is not typically observed. The current study demonstrates the graphitization of 150 nm HP-HT nanodiamond particles in ca. 20-μm-thick thin films formed on a glass substrate when the intensity of a focused 633 nm He-Ne laser exceeds a threshold of ~ 33 kW/cm2. Graphitization is accompanied by green luminescence. The structure and morphology of the samples were investigated before and after laser excitation while using X-ray diffraction (XRD), Raman spectroscopy, atomic force (AFM), and scanning electron microscopy (SEM). These observations are explained by photoionization of [Ni-N]- and [N]-centers, leading to the excitation of electrons to the conduction band of the HP-HT nanodiamond films and an increase of the local temperature of the sample, causing the transformation of sp3 HP-HT nanodiamonds to sp2-carbon.

scholarly journals Microstructure and Tensile Properties of Diffusion Bonded Austenitic Fe-Base Alloys—Before and After Exposure to High Temperature Supercritical-CO2

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 480 ◽  
Author(s):  
Sung Hwan Kim ◽  
Ji-Hwan Cha ◽  
Changheui Jang ◽  
Injin Sah
Keyword(s):  
High Temperature ◽  
Tensile Properties ◽  
Heat Exchangers ◽  
Boundary Migration ◽  
Bond Line ◽  
Grain Boundary Migration ◽  
Compact Type ◽  
Before And After ◽  
Temperature Exposure ◽  
Co2 Environment

Austenitic Fe-base alloys, SS 316H and Alloy 800HT, were diffusion bonded for use in compact-type heat exchangers in supercritical-carbon dioxide (S-CO2) Brayton cycles. For diffusion bonded 316H, grain boundary migration across the bond-line was observed despite the formation of some Cr-rich carbide, and its tensile properties were similar to those of as-received 316H. However, diffusion bonded Alloy 800HT exhibited severely degraded elongation compared to as-received 800HT due to the formation of continuous Ti-rich carbides along the bond-line. Post-bond heat treatment (PBHT) was found to improve elongation at fracture for diffusion bonded alloys. However, a subsequent corrosion test in S-CO2 at 600 °C (20 MPa) for 1000 h resulted in a loss of elongation. This was much more severe for PBHT-ed 800HT due to the formation of Cr-rich carbides at the bond-line. Meanwhile, it was found that the effect of ageing on loss of elongation during high temperature exposure was greater than that of S-CO2 environment.

Methodology for Calculating the Technical State of a Reinforced-Concrete Fragment in a Building Influenced by High Temperature

2020 ◽  
Vol 1006 ◽  
pp. 166-172
Author(s):  
Olha Bashynska ◽  
Yurii Otrosh ◽  
Oleksandr Holodnov ◽  
Andrey Tomashevskyi ◽  
Galyna Venzhego
Keyword(s):  
Reinforced Concrete ◽  
High Temperature ◽  
Technical State ◽  
Temperature Fields ◽  
Fire Extinguishing ◽  
Load Carrying ◽  
Calculation Methodology ◽  
Temperature Exposure ◽  
Temperature Heating

The purpose of research was to develop a methodology for testing the fire-resistant quality of a building fragment influenced by a real fire to substantiate the main calculation methodology provisions and determine the residual load-carrying ability. While testing, it was supposed to determine the technical state of reinforced-concrete structures after high-temperature exposure and further intensive extinguishment. High-temperature heating and further fire extinguishing with water leads to the surface layers’ destruction and weakening of concrete. Impact on the structures of the open air leads to destruction and delamination of weakened concrete with further exposing of reinforcement and its corrosion. The approach, implemented in LIRA-SAPR software package, makes possible to take into account the influence of changes in the temperature regime of operation on the stress-strain state of the structure. After determining the temperature fields, it is necessary to reduce the rigidity characteristics of materials and perform a calculation of strength. When using this approach in order to determine the total deformations of the structure, it is necessary to take into account the creep deformation.

Evaluation on Microstructure Stability and Thermal Resistant Ability at High Temperature of Ternary-Blended Geopolymer

2021 ◽  
Vol 321 ◽  
pp. 73-79
Author(s):  
Hoc Thang Nguyen
Keyword(s):  
High Temperature ◽  
Rice Husk Ash ◽  
High Thermal Stability ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microstructure Stability ◽  
Before And After ◽  
Materials Used

Stability of microstructure and heat resistant ability at high temperature is one of the important properties in ceramics or silicate materials which are normally exposed with fire such as refractories and insulation or other materials used in furnaces. This study used a ternary-blended geopolymer which was synthesized from an optimized mixture of red mud (RM), rice husk ash (RHA), diatomaceous earth (DE), and water glass solution (WGS) with silica modulus of 2.5. The geopolymer samples were tested thermal properties of heat resistance (%), volumetric shrinkage (%), mass loss (%) at 1000°C to evaluate thermal resistant ability. Changes of microstructure of the ternary-blended geopolymer samples were also characterized before and after exposed at high temperature using methods of X-ray diffraction (XRD), Thermogravimetric analysis or thermal gravimetric analysis (DTA-TGA), and Scanning electron microscope (SEM). The experimental results showed the ternary-blended geopolymer has high thermal stability and unchanged microstructure even at high temperatures. Hence, the geopolymer in this study is suggested to apply as an insolation with the upper limit of temperature to work at 1000°C.

scholarly journals Response of Mycorrhizal ’Touriga Nacional‘ Variety Grapevines to High Temperatures Measured by Calorespirometry and Near-Infrared Spectroscopy

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1499
Author(s):  
Amaia Nogales ◽  
Hugo Ribeiro ◽  
Julio Nogales-Bueno ◽  
Lee D. Hansen ◽  
Elsa F. Gonçalves ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Near Infrared ◽  
Nir Spectroscopy ◽  
Temperature Adaptation ◽  
Biochemical Processes ◽  
Before And After ◽  
Heat Shocks ◽  
Temperature Exposure ◽  
Sensitive Parameters

Heat stress negatively affects several physiological and biochemical processes in grapevine plants. In this work, two new methods, calorespirometry, which has been used to determine temperature adaptation in plants, and near-infrared (NIR) spectroscopy, which has been used to determine several grapevine-related traits and to discriminate among varieties, were tested to evaluate grapevine response to high temperatures. ‘Touriga Nacional’ variety grapevines, inoculated or not with Rhizoglomus irregulare or Funneliformis mosseae, were used in this study. Calorespirometric parameters and NIR spectra, as well as other parameters commonly used to assess heat injury in plants, were measured before and after high temperature exposure. Growth rate and substrate carbon conversion efficiency, calculated from calorespirometric measurements, and stomatal conductance, were the most sensitive parameters for discriminating among high temperature responses of control and inoculated grapevines. The results revealed that, although this vine variety can adapt its physiology to temperatures up to 40 °C, inoculation with R. irregulare could additionally help to sustain its growth, especially after heat shocks. Therefore, the combination of calorespirometry together with gas exchange measurements is a promising strategy for screening grapevine heat tolerance under controlled conditions and has high potential to be implemented in initial phases of plant breeding programs.

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