scholarly journals Dynamic Disturbance and Error Analysis of Flexible Support System for Large Optical Mirror Processing

2021 ◽  
Vol 11 (6) ◽  
pp. 2715
Author(s):  
Zujin Jin ◽  
Gang Cheng ◽  
Shichang Xu ◽  
Wei Gu
Keyword(s):  
Ambient Temperature ◽  
Temperature Change ◽  
Support System ◽  
Support Pressure ◽  
Ambient Temperatures ◽  
Flexible Support ◽  
Working Medium ◽  
Lower Chamber ◽  
Disturbance Model ◽  
Pressure Changes

To improve the accuracy of a flexible support system (FSS) used for optical mirror processing, the influence of air content in the working medium and ambient temperature change on the FSS is analyzed and studied. First, the disturbance model of the FSS and single support cylinder affected by different air contents in the working medium and ambient temperature is established, and the mapping relationship between the influencing factors and the affected factors is analyzed. Then, the effects of ambient temperature change on volume, support height, and support pressure for different air contents are simulated and analyzed separately. The results of the simulation obtained show that when the working medium is mixed with different volume fractions of air and the ambient temperature changes, upper and lower chamber volumes, support rigidity, and support height of the support cylinder are also changed. Finally, an experimental study of pressure changes in the upper and lower chambers, support height, and support rigidity changes at different ambient temperatures and air contents are carried out. By measuring the support height, support pressure, and support rigidity error, the effectiveness of the established mathematical disturbance model of FSS is further verified. It not only provides a theoretical basis for improving the support accuracy of the FSS but also provides a foundation for the application of the FSS in the processing stage of large optical mirrors.

Effects of Ambient Temperature and Forced-air Warming on Intraoperative Core Temperature

2018 ◽  
Vol 128 (5) ◽  
pp. 903-911 ◽  
Author(s):  
Lijian Pei ◽  
Yuguang Huang ◽  
Yiyao Xu ◽  
Yongchang Zheng ◽  
Xinting Sang ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Temperature Change ◽  
Core Temperature ◽  
Negative Slope ◽  
Anesthesia Induction ◽  
Temperature Changes ◽  
Ambient Temperatures ◽  
Forced Air Warming ◽  
Factorial Trial ◽  
Forced Air

Abstract Background The effect of ambient temperature, with and without active warming, on intraoperative core temperature remains poorly characterized. The authors determined the effect of ambient temperature on core temperature changes with and without forced-air warming. Methods In this unblinded three-by-two factorial trial, 292 adults were randomized to ambient temperatures 19°, 21°, or 23°C, and to passive insulation or forced-air warming. The primary outcome was core temperature change between 1 and 3 h after induction. Linear mixed-effects models assessed the effects of ambient temperature, warming method, and their interaction. Results A 1°C increase in ambient temperature attenuated the negative slope of core temperature change 1 to 3 h after anesthesia induction by 0.03 (98.3% CI, 0.01 to 0.06) °Ccore/(h.°Cambient) (P < 0.001), for patients who received passive insulation, but not for those warmed with forced-air (–0.01 [98.3% CI, –0.03 to 0.01] °Ccore/[h.°Cambient]; P = 0.40). Final core temperature at the end of surgery increased 0.13°C (98.3% CI, 0.07 to 0.20; P < 0.01) per degree increase in ambient temperature with passive insulation, but was unaffected by ambient temperature during forced-air warming (0.02 [98.3% CI, –0.04 to 0.09] °Ccore/°Cambient; P = 0.40). After an average of 3.4 h of surgery, core temperature was 36.3° ± 0.5°C in each of the forced-air groups, and ranged from 35.6° to 36.1°C in passively insulated patients. Conclusions Ambient intraoperative temperature has a negligible effect on core temperature when patients are warmed with forced air. The effect is larger when patients are passively insulated, but the magnitude remains small. Ambient temperature can thus be set to comfortable levels for staff in patients who are actively warmed.

Analysis of the inherent characteristics of rotor-diaphragm coupling – flexible support system

2017 ◽  
Vol 3 (1) ◽  
pp. 9-16
Author(s):  
Yu Guangbin ◽  
◽  
Duan Yuanwang ◽  
Zhao Xinhui ◽  
Tian Ren ◽  
...  
Keyword(s):  
Support System ◽  
Flexible Support

scholarly journals Influence of Ambient Temperature on Radiative and Convective Heat Dissipation Ratio in Polymer Heat Sinks

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2286
Author(s):  
Jan Kominek ◽  
Martin Zachar ◽  
Michal Guzej ◽  
Erik Bartuli ◽  
Petr Kotrbacek
Keyword(s):  
Heat Transfer ◽  
Ambient Temperature ◽  
Convective Heat ◽  
Heat Dissipation ◽  
High Surface ◽  
Heat Sinks ◽  
Fourth Power ◽  
Molding Process ◽  
Ambient Temperatures ◽  
University Of Technology

Miniaturization of electronic devices leads to new heat dissipation challenges and traditional cooling methods need to be replaced by new better ones. Polymer heat sinks may, thanks to their unique properties, replace standardly used heat sink materials in certain applications, especially in applications with high ambient temperature. Polymers natively dispose of high surface emissivity in comparison with glossy metals. This high emissivity allows a larger amount of heat to be dissipated to the ambient with the fourth power of its absolute surface temperature. This paper shows the change in radiative and convective heat transfer from polymer heat sinks used in different ambient temperatures. Furthermore, the observed polymer heat sinks have differently oriented graphite filler caused by their molding process differences, therefore their thermal conductivity anisotropies and overall cooling efficiencies also differ. Furthermore, it is also shown that a high radiative heat transfer leads to minimizing these cooling efficiency differences between these polymer heat sinks of the same geometry. The measurements were conducted at HEATLAB, Brno University of Technology.

scholarly journals Insufficient Stability of Clavulanic Acid in Widely Used Child-Appropriate Formulations

Antibiotics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 225
Author(s):  
Ines Mack ◽  
Mike Sharland ◽  
Janneke M. Brussee ◽  
Sophia Rehm ◽  
Katharina Rentsch ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Clavulanic Acid ◽  
Storage Conditions ◽  
Essential Medicines ◽  
Active Components ◽  
Middle Income ◽  
Ambient Temperatures ◽  
Essential Medicines List ◽  
Dispersible Tablets ◽  
The Stability

Amoxicillin-clavulanic acid (AMC) belongs to the WHO Essential Medicines List for children, but for optimal antimicrobial effectiveness, reconstituted dry powder suspensions need to be stored in a refrigerated environment. Many patients in low- and middle-income countries who are sold AMC suspensions would be expected not to keep to the specified storage conditions. We aimed to assess the stability of both ingredients in liquid formulations and dispersible tablets, combined with nationally representative data on access to appropriate storage. Degradation of amoxicillin (AMX) and clavulanic-acid (CLA) was measured in suspensions and dispersible tablets commercially available in Switzerland at different ambient temperatures (8 °C vs. 28 °C over 7 days, and 23 °C vs. 28 °C over 24 h, respectively). Data on access to refrigeration and electricity were assessed from the USAID-funded Demographic and Health Survey program. In suspensions, CLA degraded to a maximum of 12.9% (95% CI −55.7%, +29.9%) at 8°C and 72.3% (95% CI −82.8%, −61.8%) at a 28 °C ambient temperature during an observation period of 7 days. Dispersible tablets were observed during 24 h and CLA degraded to 15.4% (95% CI −51.9%, +21.2%) at 23 °C and 21.7% (−28.2%, −15.1%) at a 28 °C ambient temperature. There is relevant degradation of CLA in suspensions during a 7-day course. To overcome the stability challenges for all active components, durable child-appropriate formulations are needed. Until then, prescribers of AMC suspensions or pharmacists who sell the drug need to create awareness for the importance of proper storage conditions regarding effectiveness of both antibiotics and this recommendation should be reflected in the WHO Essential Medicines List for children.

Ambient temperature effects on physiological traits of white-tailed deer

1975 ◽  
Vol 53 (6) ◽  
pp. 679-685 ◽  
Author(s):  
J. B. Holter ◽  
W. E. Urban Jr. ◽  
H. H. Hayes ◽  
H. Silver ◽  
H. R. Skutt
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Energy Expenditure ◽  
Ambient Temperature ◽  
Temperature Effects ◽  
Temperature Changes ◽  
Wind Chill ◽  
Ambient Temperatures ◽  
Energy Equilibrium ◽  
Body Energy

Six adult white-tailed deer (Odocoileus virginianus borealis) were exposed to 165 periods of 12 consecutive hours of controlled constant ambient temperature in an indirect respiration calorimeter. Temperatures among periods varied from 38 to 0 (summer) or to −20C (fall, winter, spring). Traits measured were energy expenditure (metabolic rate), proportion of time spent standing, heart rate, and body temperature, the latter two using telemetry. The deer used body posture extensively as a means of maintaining body energy equilibrium. Energy expenditure was increased at low ambient temperature to combat cold and to maintain relatively constant body temperature. Changes in heart rate paralleled changes in energy expenditure. In a limited number of comparisons, slight wind chill was combatted through behavioral means with no effect on energy expenditure. The reaction of deer to varying ambient temperatures was not the same in all seasons of the year.

Research on Thermally Induced Deformation of Reinforcing Plate Based on Finite Element Simulation

2012 ◽  
Vol 197 ◽  
pp. 139-143
Author(s):  
Hua Bai ◽  
Yi Du Zhang
Keyword(s):  
Finite Element ◽  
Ambient Temperature ◽  
Finite Element Simulation ◽  
Temperature Change ◽  
Large Scale ◽  
Machining Process ◽  
Reinforcement Structure ◽  
Thermally Induced ◽  
Finite Element Software ◽  
Element Simulation

The change of ambient temperature will cause deformation during the machining process of large-scale aerospace monolithic component. Based on finite element simulation, thermally induced deformation of reinforcing plate is studied in such aspects as reinforcement structure, clamping method and temperature change, and contact function in finite element software is used to simulate the unilateral constraint between workpiece and worktable. The results indicate that reinforcing plate will produce warping deformation due to the change of ambient temperature. Different reinforcement structures and clamping methods have important influence on the deformation positions and degrees, and the deformation is proportional to the temperature change.

Design and Fabrication of a Magnetocaloric Microcooler

2005 ◽  
Author(s):  
Sangchae Kim ◽  
Bharath Bethala ◽  
Simone Ghirlanda ◽  
Senthil N. Sambandam ◽  
Shekhar Bhansali
Keyword(s):  
Magnetic Field ◽  
Ambient Temperature ◽  
Temperature Change ◽  
Entropy Change ◽  
Temperature Sensors ◽  
Experimental Results ◽  
Maximum Temperature ◽  
Alternative Technology ◽  
Temperature Conditions ◽  
Si Wafer

Magnetocaloric refrigeration is increasingly being explored as an alternative technology for cooling. This paper presents the design and fabrication of a micromachined magnetocaloric cooler. The cooler consists of fluidic microchannels (in a Si wafer), diffused temperature sensors, and a Gd5(Si2Ge2) magnetocaloric refrigeration element. A magnetic field of 1.5 T is applied using an electromagnet to change the entropy of the magnetocaloric element for different ambient temperature conditions ranging from 258 K to 280 K, and the results are discussed. The tests show a maximum temperature change of 7 K on the magnetocaloric element at 258 K. The experimental results co-relate well with the entropy change of the material.

Change in the Properties of a Lead-acid Battery Depending on the Cycling Speed and the Ambient Temperature

2021 ◽  
Vol 105 (1) ◽  
pp. 119-134
Author(s):  
Jana Zimáková ◽  
Petr Baca ◽  
Martin Langer ◽  
Tomáš Binar
Keyword(s):  
Ambient Temperature ◽  
High Temperatures ◽  
Room Temperature ◽  
Lead Acid Battery ◽  
Ambient Temperatures ◽  
Lead Acid Batteries ◽  
Temperature Dependences ◽  
Cycling Speed ◽  
Lead Acid

This work deals with lead-acid batteries, their properties and individual types that are available on the market. The temperature dependences of the battery parameters at different ambient temperatures and at different discharging and charging modes are measured. 6 batteries are tested at different charging currents, which provides information about their behavior both during discharge and at the time of charging. During the experiments, testing is not only performed at room temperature, but the batteries are also exposed to high temperatures up to 75 °C.

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