Low Temperature Testing of Ultrasound Sensors in Liquid Nitrogen

2021 ◽  
Author(s):  
Joseph Chul Chung ◽  
Michael Myung-Sub Lee ◽  
Sejong Chun ◽  
Inseok Yang
Keyword(s):  
Low Temperature ◽  
Liquid Nitrogen ◽  
Flow Measurement ◽  
Temperature Scale ◽  
Fiber Optic ◽  
Measurement Techniques ◽  
Fiber Optic Sensors ◽  
Ultrasound Waves ◽  
Flow Metering ◽  
Temperature Ranges

Abstract Ultrasonic flow metering is one of flow measurement techniques applicable to low temperature environment. Unlike pipe provers or Coriolis mass flowmeters, ultrasonic flowmeters require waveguides in front of ultrasound sensors. The waveguides can prevent heat conduction from the ultrasound sensors to low temperature liquids, such as liquid nitrogen. The ultrasound sensors can maintain its piezoelectricity within the specified temperature ranges by thermal insulation of the waveguides. In this study, low temperature testing on a pair of ultrasound sensors was performed to see if ultrasound waves could be transmitted normally through liquid nitrogen. A flowmeter cell with diameter of 300 mm (equivalently, 12”) was used as a container for liquid nitrogen. Three pairs of ultrasound sensors were installed in the flowmeter cell. Fiber-optic sensors were also attached on its inner wall to measure the temperature of liquid nitrogen. As a result, ultrasound waves were successfully transmitted between a pair of ultrasound sensors by using a preamplifier. The fiber-optic sensors could measure the temperature of liquid nitrogen although the sensors were not calibrated by the reference temperature scale at KRISS.

Preparation and Properties of Amorphous Tl2SexTe1−x Films

1974 ◽  
Vol 52 (2) ◽  
pp. 187-192 ◽  
Author(s):  
J. J. Harris ◽  
D. E. Brodie ◽  
P. C. Eastman
Keyword(s):  
Low Temperature ◽  
Liquid Nitrogen ◽  
Growth Temperature ◽  
Activation Energies ◽  
Amorphous Semiconductors ◽  
Compositional Dependence ◽  
Flash Evaporation ◽  
Thermally Activated ◽  
Temperature Ranges ◽  
Temperature Conduction

Films of amorphous Tl2SexTe1−x, with x values of 0, 0.25, 0.5, 0.75, and 1, have been prepared by flash evaporation of mixed powders of Tl2Se and Tl2Te. These films show thermally activated conduction with up to four distinct activation energies, in different temperature ranges, as the samples are warmed from their liquid-nitrogen growth temperature; they then undergo spontaneous recrystallization at temperatures near 300 K. The low-temperature conduction in these samples is consistent with the model of amorphous semiconductors proposed by Davis and Mott, and the compositional dependence of the parameters of this model are presented and discussed.

Intracellular structures of rapid frozen biological samples observed by high-resolution low-temperature Scanning Electron Microscopy

1989 ◽  
Vol 47 ◽  
pp. 736-737
Author(s):  
T. Inoué ◽  
H. Koike
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Low Temperature ◽  
Liquid Nitrogen ◽  
Specimen Preparation ◽  
Chemical Fixation ◽  
Brown Adipose ◽  
Critical Point Drying ◽  
Temperature Scanning ◽  
Scanning Electron

Low temperature scanning electron microscopy (LTSEM) is useful to avoid artifacts such as deformation and extraction, because specimens are not subjected to chemical fixation, dehydration and critical-point drying. Since Echlin et al developed a LTSEM, many techniques and instruments have been reported for observing frozen materials. However, intracellular structures such as mitochondria and endoplasmic reticulum have been unobservable by the method because of the low resolving power and inadequate specimen preparation methods. Recently, we developed a low temperature SEM that attained high resolutions. In this study, we introduce highly magnified images obtained by the newly developed LTSEM, especially intracellular structures which have been rapidly frozen without chemical fixation.[Specimen preparations] Mouse pancreas and brown adipose tissues (BAT) were used as materials. After the tissues were removed and cut into small pieces, the specimen was placed on a cryo-tip and rapidly frozen in liquid propane using a rapid freezing apparatus (Eiko Engineering Co. Ltd., Japan). After the tips were mounted on the specimen stage of a precooled cryo-holder, the surface of the specimen was manually fractured by a razor blade in liquid nitrogen. The cryo-holder was then inserted into the specimen chamber of the SEM (ISI DS-130), and specimens were observed at the accelerating voltages of 5-8 kV. At first the surface was slightly covered with frost, but intracellular structures were gradually revealed as the frost began to sublimate. Gold was then coated on the specimen surface while tilting the holder at 45-90°. The holder was connected to a liquid nitrogen reservoir by means of a copper braid to maintain low temperature.

Nursing Movement Monitoring System Utilizing Hetero-core Fiber Optic Sensors Embedded in Medical Thin Films

2018 ◽  
Vol 138 (12) ◽  
pp. 525-532
Author(s):  
Masahiko Ito ◽  
Yuya Koyama ◽  
Michiko Nishiyama ◽  
Emi Yanagisawa ◽  
Mariko Hayashi ◽  
...  
Keyword(s):  
Thin Films ◽  
Monitoring System ◽  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Core Fiber ◽  
Movement Monitoring

Embedded Fiber Optic Sensors for Integral Armor

2000 ◽  
Author(s):  
Bruce K. Fink ◽  
Kelli Corona-Bittick
Keyword(s):  
Fiber Optic ◽  
Fiber Optic Sensors

Erratum to “Angle-Resolved Characterization and Ray-Optics Modeling of Fiber-Optic Sensors”

2021 ◽  
Vol 39 (1) ◽  
pp. 336-336
Author(s):  
George. Y. Chen ◽  
Christophe A. Codemard ◽  
Philip M. Gorman ◽  
Jaclyn S. Chan ◽  
Michalis N. Zervas
Keyword(s):  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Ray Optics

scholarly journals Compressive Strength Gain Behavior and Prediction of Cement-Stabilized Macadam at Low Temperature Curing

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yongli Xu ◽  
Guang Yang ◽  
Hongyuan Zhao
Keyword(s):  
Compressive Strength ◽  
Low Temperature ◽  
Curing Temperature ◽  
Strength Development ◽  
Construction Process ◽  
Strength Gain ◽  
Estimation Model ◽  
Maturity Method ◽  
Temperature Ranges ◽  
Natural Temperature

For cement-based materials, the curing temperature determines the strength gain rate and the value of compressive strength. In this paper, the 5% cement-stabilized macadam mixture is used. Three indoor controlled temperature curing and one outdoor natural curing scenarios are designed and implemented to study the strength development scenario law of compressive strength, and they are standard temperature curing (20°C), constant low temperature curing (10°C), day interaction temperature curing (varying from 6°C to 16°C), and one outdoor natural temperature curing (in which the air temperature ranges from 4°C to 20°C). Finally, based on the maturity method, the maturity-strength estimation model is obtained by using and analyzing the data collected from the indoor tests. The model is proved with high accuracy based on the validated results obtained from the data of outdoor tests. This research provides technical support for the construction of cement-stabilized macadam in regions with low temperature, which is beneficial in the construction process and quality control.

Fiber optic sensors for characterization of composite structural materials and structural monitoring

1997 ◽  
Author(s):  
Robert P. Kenny ◽  
E. Gutierrez ◽  
Alfredo C. Lucia ◽  
Maurice P. Whelan ◽  
F. Gaiazzi
Keyword(s):  
Fiber Optic ◽  
Structural Materials ◽  
Fiber Optic Sensors ◽  
Structural Monitoring
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