Development of hysteretic energy compatible endurance time excitations and its application

2018 ◽  
Vol 177 ◽  
pp. 753-769 ◽  
Author(s):  
Mohammadreza Mashayekhi ◽  
Homayoon E. Estekanchi ◽  
Hassan Vafai ◽  
S. Ali Mirfarhadi
Keyword(s):  
Endurance Time ◽  
Hysteretic Energy

scholarly journals Performance-based optimal distribution of viscous dampers in ‎structure using hysteretic energy compatible endurance time excitations

2021 ◽  
Vol 5 (3) ◽  
pp. 46-55
Author(s):  
A. Shirkhani ◽  
B. Farahmand Azar ◽  
M. Charkhtab Basim ◽  
M. Mashayekhi ◽  
◽  
...  
Keyword(s):  
Optimal Distribution ◽  
Viscous Dampers ◽  
Endurance Time ◽  
Hysteretic Energy

Skin Cooling on Breath-Hold Duration and Predicted Emergency Air Supply Duration During Immersion

2020 ◽  
Vol 91 (7) ◽  
pp. 578-585
Author(s):  
Victory C. Madu ◽  
Heather Carnahan ◽  
Robert Brown ◽  
Kerri-Ann Ennis ◽  
Kaitlyn S. Tymko ◽  
...  
Keyword(s):  
Minute Ventilation ◽  
Hold Time ◽  
Whole Body ◽  
Breath Hold ◽  
Endurance Time ◽  
Skin Exposure ◽  
Breathing Apparatus ◽  
Air Supply ◽  
Skin Cooling ◽  
Breath Hold Duration

PURPOSE: This study was intended to determine the effect of skin cooling on breath-hold duration and predicted emergency air supply duration during immersion.METHODS: While wearing a helicopter transport suit with a dive mask, 12 subjects (29 ± 10 yr, 78 ± 14 kg, 177 ± 7 cm, 2 women) were studied in 8 and 20°C water. Subjects performed a maximum breath-hold, then breathed for 90 s (through a mouthpiece connected to room air) in five skin-exposure conditions. The first trial was out of water for Control (suit zipped, hood on, mask off). Four submersion conditions included exposure of the: Partial Face (hood and mask on); Face (hood on, mask off); Head (hood and mask off); and Whole Body (suit unzipped, hood and mask off).RESULTS: Decreasing temperature and increasing skin exposure reduced breath-hold time (to as low as 10 ± 4 s), generally increased minute ventilation (up to 40 ± 15 L · min−1), and decreased predicted endurance time (PET) of a 55-L helicopter underwater emergency breathing apparatus. In 8°C water, PET decreased from 2 min 39 s (Partial Face) to 1 min 11 s (Whole Body).CONCLUSION: The most significant factor increasing breath-hold and predicted survival time was zipping up the suit. Face masks and suit hoods increased thermal comfort. Therefore, wearing the suits zipped with hoods on and, if possible, donning the dive mask prior to crashing, may increase survivability. The results have important applications for the education and preparation of helicopter occupants. Thermal protective suits and dive masks should be provided.Madu VC, Carnahan H, Brown R, Ennis K-A, Tymko KS, Hurrie DMG, McDonald GK, Cornish SM, Giesbrecht GG. Skin cooling on breath-hold duration and predicted emergency air supply duration during immersion. Aerosp Med Hum Perform. 2020; 91(7):578–585.

Application of the endurance time methodology on seismic analysis and performance assessment of hydraulic arched tunnels

2021 ◽  
Vol 115 ◽  
pp. 104022
Author(s):  
Benbo Sun ◽  
Mingjiang Deng ◽  
Sherong Zhang ◽  
Chao Wang ◽  
Yang Li ◽  
...  
Keyword(s):  
Performance Assessment ◽  
Seismic Analysis ◽  
Endurance Time ◽  
And Performance

scholarly journals Simultaneously Enhanced Thermal Conductivity and Breakdown Performance of Micro/Nano-BN Co-Doped Epoxy Composites

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3521
Author(s):  
Chuang Zhang ◽  
Jiao Xiang ◽  
Shihang Wang ◽  
Zhimin Yan ◽  
Zhuolin Cheng ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
High Frequency ◽  
Breakdown Strength ◽  
Epoxy Composites ◽  
Endurance Time ◽  
Insulating Materials ◽  
Power Frequency ◽  
High Frequency Devices ◽  
Co Doped ◽  
Enhanced Thermal Conductivity

Micro/nano- BN co-doped epoxy composites were prepared and their thermal conductivity, breakdown strength at power frequency and voltage endurance time under high frequency bipolar square wave voltage were investigated. The thermal conductivity and breakdown performance were enhanced simultaneously in the composite with a loading concentration of 20 wt% BN at a micro/nano proportion of 95/5. The breakdown strength of 132 kV/mm at power frequency, the thermal conductivity of 0.81 W∙m−1∙K−1 and voltage endurance time of 166 s were obtained in the composites, which were approximately 28%, 286% and 349% higher than that of pristine epoxy resin. It is proposed that thermal conductive pathways are mainly constructed by micro-BN, leading to improved thermal conductivity and voltage endurance time. A model was introduced to illustrate the enhancement of the breakdown strength. The epoxy composites with high thermal conductivity and excellent breakdown performance could be feasible for insulating materials in high-frequency devices.

Thermal Stress and the Contribution of Radiant Heat

1980 ◽  
Vol 66 (1) ◽  
pp. 45-49
Author(s):  
D. J. Smith
Keyword(s):  
Radiant Heat ◽  
The Other ◽  
Endurance Time ◽  
Deep Body Temperature ◽  
Cardiovascular Stress ◽  
Globe Temperature ◽  
Climatic Severity ◽  
The Relationship ◽  
Deep Body ◽  
Different Climates

AbstractSixteen young, healthy volunteers were exposed to eight thermally severe environments, each subject being exposed to four different climates. Four climates had a radiant heat component; globe temperature some 10°C above dry bulb. In the other four climates, the globe temperature was close to the dry bulb. Measurements of endurance time in the different climates were made, as were changes in deep body temperature and heart rate. The relationship between the wet bulb globe thermometer index (WBGT) and stay times in the non-radiant climates agreed well with that of previous workers. Further, the WBGT index appeared adequate, in the situation under study, in terms of its ability to quantify climatic severity, thermal and cardiovascular stress and hence endurance in climates with a high radiant heat component.

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