thermal kinetics
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2021 ◽  
pp. 131622
Author(s):  
Aluizio F. Carvalho-Filho ◽  
Ana C.S. Alcântara ◽  
Antônio E.M. Paiva ◽  
Jorge J. Passinho-Silva ◽  
Javier Perez-Carvajal ◽  
...  

2021 ◽  
Vol 514 ◽  
pp. 230582
Author(s):  
Yu Wang ◽  
Dongsheng Ren ◽  
Xuning Feng ◽  
Li Wang ◽  
Minggao Ouyang
Keyword(s):  

Author(s):  
M Marc Abreu ◽  
Ricardo L Smith ◽  
Trevor M Banack ◽  
Alexander C Arroyo ◽  
Robert F Gochman ◽  
...  

For centuries, temperature measurement deficiencies attributable to biological barriers and low thermo-conductivity (k) have precluded accurate surface-based fever assessment. At this stage of the pandemic, infection detection in children (who due to immature immune system may not effectively respond to vaccines) is critical because children can be readily infected and also become a large mutation reservoir. We reveal hitherto-unrecognized worldwide body temperature measurements (T°), in children and adults, over tissue typified by low-k similar to wood that may reach 6.8°C in thermal variability, hampering thereby COVID-19 control. Brain-eyelid thermal tunnels’ (BTT) integration of low-k and high-k regions creating a thermal pathway for undisturbed heat transmission from hypothalamus to high-k skin eliminates current shortcomings and makes the brain indispensable for defeating COVID-19 given that brain thermoregulatory signals are not limited by mutations. Anatomo-histologic, emissive, physiologic, and thermometric bench-to-bedside studies characterized and overcome biophysical limitations of thermometry through high-k eyelid-enabled brain temperature measurements in children and adults. BTT eyelid features fat-free skin (~900 µm) and unique light emission through a blood/fat configuration in the underlying tunnel. Contrarily, forehead features variable and thick dermis (2000–2500 µm) and variable fat layers (1100–2800 µm) resulting in variable low-k as well as temperatures 1.97 °C lower than BTT temperature (BTT°). Highest emission present in only ~3.1% of forehead averaged 1.08±0.49 °C (mean±SD) less than BTT° (p=0.008). Environmental and biological impacts during fanning revealed thermal imaging limitations for COVID-19 screening. Comparison of paired measurements for 100 pediatric patients showed that in the children subgroup above 37°C, BTT° exceeded body core temperature (Core°) in 60/72 patients; the average difference in the 72 patients was 0.62±0.7°C  (p<0.001 by unpaired t-test); and in the subgroup beyond 37.5°C, BTT° exceeded Core° in 30/32 patients. Delineating hypothalamic activity in children facilitates early infection detection, which is essential because children’s immunogenicity prevents effective vaccination and causes accelerated viral evolution. Capturing hypothalamic thermal signals from BTT was further supported by brain thermal kinetics via BTT using wearables during anesthesia, sedation, sleep, brain injury, exercise, and asymptomatic infection, which revealed brain/core discordance and enabled automated noninvasive afebrile infection detection for interrupting asymptomatic human-to-human transmission. BTT-based spot-check thermometry can be harmlessly implemented for children worldwide without undue burden and costs; meanwhile, continuous brain-eyelid T° in concert with biological and physical principles affords a new dimension for combating pandemics. The “detection–vaccination” pair solution presented is required to mitigate COVID-19 from spreading indefinitely through mutations and vaccine evasion while opening a viable path for eradicating COVID-19.


2021 ◽  
Vol 9 (2) ◽  
pp. 700-711
Author(s):  
Sani Jirasatid ◽  
Montira Nopharatana

The thermal kinetics of changes of –aminobutyric acid (GABA) and antioxidant activity (DPPH assay) in germinated red jasmine rice milk (GRJM) at heating temperatures of 80, 90, 100 and 121C using Arrhenius, Eyring–Polanyi and Ball models was examined in this study. Under isothermal conditions, the increasing of heating temperature from 80C to 121C resulted in the decreasing of GABA. However, DPPH radical scavenging activity increased under temperature range of 80–100C, but decreased at 121C. The highest residue of GABA was 94% after heating at 80C for 30 min, while the highest increasing of DPPH radical scavenging activity was 230% at 90C for 30 min. Thermal degradation of GABA followed a second–order reaction kinetic, while the increasing of antioxidant activity (80–100C) followed a first–order kinetic as well as the degradation of antioxidant activity (121C). The heating temperature dependence of rate constant for degradation of GABA and increasing of antioxidant activity were described by Arrhenius, Eyring–Polanyi and Ball models. Following the Arrhenius law, activation energies were 59.62 kJ/mol and 30.31 kJ/mol, respectively for degradation of GABA (80–121C) and increasing of antioxidant activity in GRJM (80–100C). Arrhenius, Eyring–Polanyi and Ball models could be used to predict accurately GABA content and antioxidant activity in GRJM during isothermal heat treatment.


Silicon ◽  
2021 ◽  
Author(s):  
Saikat Das ◽  
R. Govinda Rao ◽  
Prasanta Kumar Rout

Author(s):  
Xiaoliang Zhang ◽  
Haobo Wang ◽  
Zhangrui Liu ◽  
Fanjie Liang ◽  
Boyang Shen

Author(s):  
Sandip Karmakar ◽  
Tapas Kumar Roy

The price of raw polymers used for making most of the waste plastics has confined the implementation of polymer modified bitumen (PMB) only to the major road projects. In view of the same, an attempt to make a PMB by such wastes was considered as a “state-of-art” in this investigation. Therefore, the different proportions of waste plastic fractions were blended with the pristine bitumen and the resulting blend characterized by thermal kinetics analysis, microstructural analysis, and Marshall mix design, respectively. The major findings have predicted the highest thermal stability of the blend was achieved by mixing plastic bags, plastic milk pouches, and plastic cups together in proportion of 2:0.25:1 to virgin bitumen with no thermal decomposition. Further, uniform dispersion of “bee-like structure” in that blend has reflected its homogeneity. Besides, such modified bitumen has elevated the Marshall quotient of the bituminous mix by 16%, which can preferentially be used in the rural roads safely, confirmed by Marshall mix design.


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