scholarly journals Research on the Creep Characteristics of Thermal Insulation Shotcrete under the Action of Temperature and Humidity Circulation

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jinsong Zhang ◽  
Yaxing Wang ◽  
Junjun Liu ◽  
Jiuqun Zou
Keyword(s):  
Thermal Insulation ◽  
Deformation Modulus ◽  
Bath Temperature ◽  
Water Bath ◽  
Steady State Creep Rate ◽  
Creep Characteristics ◽  
Temperature And Humidity ◽  
Instantaneous Deformation ◽  
Drying And Wetting Cycles ◽  
Adjacent Cycles

In order to explore the creep characteristics of thermal insulation shotcrete under the action of temperature and humidity circulation, a series of uniaxial compression creep tests were carried out with different cycles of temperature and humidity and hierarchical loading conditions. The test results show that the axial creep deformation and creep strain of the thermal insulation shotcrete specimens increase with the increase of the number of drying and wetting cycles under normal temperature water bath condition. After 28 cycles, the deformation value becomes larger obviously, and the creep strain increases greatly in the precycle period. The thermal insulation shotcrete axial steady-state creep rate increases nonlinearly with the increase of the number of drying and wetting cycles under different stress levels. When the number of adjacent cycles is 0–3, the average increase is larger, and the axial steady-state creep rate of thermal insulation shotcrete for 28 cycles increases with the increase of water bath temperature. The instantaneous deformation modulus of thermal insulation shotcrete decreases logarithmically with the increase of the number of drying and wetting cycles, and the total deterioration degree of the average instantaneous deformation modulus increases gradually, but the deterioration degree between adjacent cycles decreases successively. The thermal insulation shotcrete specimens with 3 cycles of fracture were mainly stretched, and with the increase of the water bath temperature, the specimen was damaged by shear failure. When the water bath temperature is 40°C, the fracture degree of the specimen increases first and then decreases with the increase of the number of cycles.

scholarly journals Creep damage behavior of red sandstone after high temperature

2021 ◽  
Author(s):  
Xiaokang Pan ◽  
Filippo Berto ◽  
Xiaoping Zhou
Keyword(s):  
High Temperature ◽  
Uniaxial Compression ◽  
Deformation Modulus ◽  
Creep Damage ◽  
Viscosity Coefficient ◽  
Creep Tests ◽  
Red Sandstone ◽  
Instantaneous Strain ◽  
Treated Sample ◽  
Instantaneous Deformation

This work discusses the results from tests conducted to investigate the uniaxial compression and creep behavior of red sandstone. The original untreated sample and the 800 ℃ treated sample have been selected to carry out the experiments. It has been found that high temperature has obvious influence on the mechanical properties of red sandstone. The relationship between creep strain and instantaneous strain, as well as instantaneous deformation modulus and creep viscosity coefficient have been analyzed. It has been found that high temperature reduces the ability of red sandstone to resist instantaneous deformation and creep deformation. Acoustic emission (AE) technology has been also used in the loading process of uniaxial compression and creep tests, providing a powerful means for damage evolution analysis of red sandstone.

Research of Artificial Rumen Constant Temperature Water Bath Based on Fuzzy Logic Controller

2014 ◽  
Vol 602-605 ◽  
pp. 2487-2490
Author(s):  
Xi Wu Li ◽  
Bo Xu
Keyword(s):  
Fuzzy Control ◽  
Constant Temperature ◽  
Fuzzy Logic Controller ◽  
Control Unit ◽  
Bath Temperature ◽  
Water Bath ◽  
Dynamic Responses ◽  
Test Operation ◽  
Constant Temperature Water Bath ◽  
Temperature Water

In the artificial rumen device constant temperature water bath temperature control for model and parameter uncertainty is proposed that 89S51 microcontroller as the control core, using fuzzy control algorithm, realized thermostatically control of water bath temperature. This paper presents the overall system architecture and design philosophy of fuzzy control unit and associated circuits. Systematic simulation and test operation showed that: the good dynamic responses of the system, high precision control, strong robustness, achieve better control of the water bath temperature.

scholarly journals Preparation and Optimization of Waterborne Acrylic Core Microcapsules for Waterborne Wood Coatings and Comparison with Epoxy Resin Core

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2366 ◽  
Author(s):  
Xiaoxing Yan ◽  
Yu Tao ◽  
Xingyu Qian
Keyword(s):  
In Situ Polymerization ◽  
Urea Formaldehyde ◽  
Paint Film ◽  
Bath Temperature ◽  
Water Bath ◽  
Core Material ◽  
Wall Material ◽  
Formaldehyde Resin ◽  
The Core ◽  
Resin Core

Microcapsules were prepared by in situ polymerization with urea formaldehyde resin as the wall material and Dulux waterborne acrylic acid as the core material. The effects of the core–wall ratio, water bath temperature and depositing time on the morphology, particle size, yield and encapsulation ratio of microcapsules were investigated by orthogonal experiment of three factors and two levels. The results showed that the core–wall ratio had the greatest influence on the performance of microcapsules. When the core–wall ratio was 0.58:1, the water bath temperature was 70 °C, and the depositing time was 5 d, the microcapsule performance was the best. With the increase in depositing time, the yield of microcapsule particles increased gradually, and the microcapsules appeared to show an adhesive phenomenon. However, the long-term depositing time did not lead to complete deposition and agglomeration of microcapsules. When 10.0% concentration of the waterborne acrylic microcapsules with 0.58:1 of core–wall ratio was added to the coatings, the mechanical and optical properties of the coatings did not decrease significantly, but the elongation at break increased significantly. Therefore, this study offers a new prospect for using waterborne acrylic microcapsules to improve the toughness of waterborne paint film which can be cured at room temperature on a wood surface.

Glass Micro-Bubbles as Additional Thermal Insulation/Shielding for Translucent and Non-Transparent Materials

2018 ◽  
Vol 776 ◽  
pp. 140-146
Author(s):  
František Novotný ◽  
Lenka Prokopová ◽  
Daniela Bošová
Keyword(s):  
Thin Layer ◽  
Surface Temperature ◽  
Thermal Insulation ◽  
Indoor Temperature ◽  
Hollow Glass ◽  
Cargo Container ◽  
Temperature And Humidity ◽  
Micro Bubble ◽  
Transparent Materials

Our research is based on innovative use of the hollow glass micro-spherical material "Glass micro-bubbles" 3MTM. We apply this material like a thin-layer additional thermal insulation/shielding for polycarbonate and steel matrices. 3 identical cargo container units with polycarbonate roof skylight are used for the research: A - without application, B - with inner application of Glass micro-bubble coating and C - with outside application of Glass micro-bubble coating.Observed parameters are translucence of daylight through layer of micro-glass bubbles on the skylight, the indoor temperature and humidity and the surface temperature of the outer and inner shell are measured.

Effect of digital nerve blockade on heat-induced vasoconstriction in the human finger

1995 ◽  
Vol 78 (2) ◽  
pp. 746-749 ◽  
Author(s):  
S. Sakurada ◽  
O. Shido ◽  
K. Yamamoto ◽  
N. Sugimoto ◽  
T. Kobayashi ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Local Anesthetic ◽  
Index Finger ◽  
Middle Finger ◽  
Bath Temperature ◽  
Water Bath ◽  
Arterial Blood ◽  
Human Finger ◽  
Local Anesthetic Injection

The present study was performed to investigate the mechanism of heat-induced vasoconstriction (HIVC) in human fingers. The left fingers of five male subjects were immersed in water controlled at an initial temperature of 35.0 degrees C. The blood flows (BF) of the left index and fourth fingers were measured continuously with laser-Doppler flowmeter probes, and the temperatures of the middle finger and water bath were also monitored continuously using thermistor probes. Arterial blood pressure and heart rate were measured every minute before and during local finger warming. A local anesthetic (0.5% bupivacaine hydrochloride) or saline at a volume of 5.0–8.0 ml was aseptically injected into the base of the fourth or index finger, respectively. After finger BFs had been stabilized for > or = 10 min, the fingers were warmed by raising the water bath temperature from 35.0 to 41.5 degrees C in 14 min. The BF of the index finger fell significantly for 6 min after local warming was commenced (at water bath temperatures between 35.5 and 37.5 degrees C) without associated changes in mean arterial blood pressure, indicating the occurrence of HIVC. Then BF increased toward prewarming levels. The local anesthetic injection, however, completely abolished HIVC in the fourth finger. These results suggest that, in humans, innervation to finger vessels is indispensable for producing HIVC and hence that a local mechanism, such as myogenic vascular response to high temperature, may not be involved in the induction of HIVC.

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