scholarly journals Thermal Load of Mine Rescuer in the Underwear and Protective Clothing with Phase Change Materials in Simulated Utility Conditions

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4320 ◽  
Author(s):  
Grażyna Bartkowiak ◽  
Anna Marszałek ◽  
Anna Dąbrowska
Keyword(s):  
Phase Change ◽  
Thermal Load ◽  
Protective Clothing ◽  
Phase Change Materials ◽  
The Body ◽  
Oxygen Breathing ◽  
Breathing Apparatus ◽  
Complete Set ◽  
Physiological Tests ◽  
Microclimate Conditions

A new set of underwear and protective clothing with phase change materials (PCM) for mine rescuers has been developed in order to increase their safety of work. It includes PCM pouches absorbing excess heat from the body. In order to evaluate thermal load of mine rescuers, physiological tests were carried out for three variants of possible use of the developed set of clothing: for mine rescuers wearing only the underwear with PCM; for a set of underwear and protective clothing; and for a complete set of clothing with closed-circuit compressed oxygen breathing apparatus. Tests were performed in difficult microclimate conditions, reflecting the typical working conditions of rescuers that cause a significant thermal load. The use of outer clothing shortened safe time of exposure to such conditions by about 36%, while the addition of respiratory protective device to this set further shortened this time to a lesser extent (by another 13%).

scholarly journals Enhanced Performance and Diffusion Robustness of Phase-Change Metasurfaces via a Hybrid Dielectric/Plasmonic Approach

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 525
Author(s):  
Joe Shields ◽  
Carlota Ruiz de Galarreta ◽  
Jacopo Bertolotti ◽  
C. David Wright
Keyword(s):  
Melting Point ◽  
Phase Change ◽  
Noble Metals ◽  
Phase Change Materials ◽  
High Efficiency ◽  
The Body ◽  
Design Stage ◽  
High Melting ◽  
Optical Performance ◽  
Electrical Conductors

Materials of which the refractive indices can be thermally tuned or switched, such as in chalcogenide phase-change alloys, offer a promising path towards the development of active optical metasurfaces for the control of the amplitude, phase, and polarization of light. However, for phase-change metasurfaces to be able to provide viable technology for active light control, in situ electrical switching via resistive heaters integral to or embedded in the metasurface itself is highly desirable. In this context, good electrical conductors (metals) with high melting points (i.e., significantly above the melting point of commonly used phase-change alloys) are required. In addition, such metals should ideally have low plasmonic losses, so as to not degrade metasurface optical performance. This essentially limits the choice to a few noble metals, namely, gold and silver, but these tend to diffuse quite readily into phase-change materials (particularly the archetypal Ge2Sb2Te5 alloy used here), and into dielectric resonators such as Si or Ge. In this work, we introduce a novel hybrid dielectric/plasmonic metasurface architecture, where we incorporated a thin Ge2Sb2Te5 layer into the body of a cubic silicon nanoresonator lying on metallic planes that simultaneously acted as high-efficiency reflectors and resistive heaters. Through systematic studies based on changing the configuration of the bottom metal plane between high-melting-point diffusive and low-melting-point nondiffusive metals (Au and Al, respectively), we explicitly show how thermally activated diffusion can catastrophically and irreversibly degrade the optical performance of chalcogenide phase-change metasurface devices, and how such degradation can be successfully overcome at the design stage via the incorporation of ultrathin Si3N4 barrier layers between the gold plane and the hybrid Si/Ge2Sb2Te5 resonators. Our work clarifies the importance of diffusion of noble metals in thermally tunable metasurfaces and how to overcome it, thus helping phase-change-based metasurface technology move a step closer towards the realization of real-world applications.

A Theoretical Investigation into Phase Change Clothing Benefits for Firefighters under Extreme Conditions

2009 ◽  
Vol 4 (3) ◽  
Author(s):  
Geoffry N. Mercer ◽  
Harvinder S Sidhu
Keyword(s):  
Mathematical Model ◽  
Thermal Properties ◽  
Phase Change ◽  
Protective Clothing ◽  
The Body ◽  
Extreme Conditions ◽  
Heat Absorption ◽  
Fire Exposure ◽  
Subcutaneous Layer ◽  
The Mathematical Model

We investigate the thermal performance of protective clothing that has an embedded phase change layer. Heat absorption due to phase change within the material is used to limit the thermal penetration of heat into the material and hence to the firefighter. The distribution of temperature within the fabric and skin during the exposure to an extreme firefighting situation is determined. To determine the protective nature of the clothing, we also include a model of the skin as three layers with differing thermal properties namely the epidermis, dermis and the subcutaneous layer. In our model, we have also incorporated the air gap between the garment and the body. The mathematical model is used to predict the duration of fire exposure during which the garment is able to protect the firefighter from getting first and second degree burns.

Design of a Novel Temperature Self-Operating Protective Clothing Based on Phase Change Material

2012 ◽  
Vol 627 ◽  
pp. 160-163
Author(s):  
Tai Qi Liu ◽  
Fu Rui Ma ◽  
Qi Song Shi ◽  
Jin Fang Chu ◽  
Tan Qiu Li ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Low Temperatures ◽  
Protective Clothing ◽  
Thermal Stresses ◽  
The Body ◽  
Large Heat ◽  
High And Low Temperatures ◽  
Change Material ◽  
Inorganic Composite

The clothing containing phase change material (PCM) with function of absorbing the body-released heat has wide applications. In this paper, a novel protective clothing based phase change material was investigated. The results show that PCM has suitable melting temperature, large heat flow, stability after repeating applications, and it is convenient for application in cooling. Moreover, the manufacturing process has a great affect on the property of the titled material. The above inorganic composite was selected to prepare the temperature self-operating protective clothing, which can efficiently lighten the demic thermal stresses at high and low temperatures.

scholarly journals A Meta Study of the Relationship Between Phase Change Material Parameters and Temperature Reduction in Fire Fighter Protective Clothing

2019 ◽  
Vol 6 ◽  
pp. 28-37
Author(s):  
Josef Richmond ◽  
Lesley Spencer ◽  
Tommy Tran ◽  
Evan Williams
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Protective Clothing ◽  
Phase Change Materials ◽  
High Heat ◽  
Heat Fluxes ◽  
Fire Fighter ◽  
High Flux ◽  
Temperature Reduction ◽  
Change Material

Firefighters are exposed to high risk scenarios in which the prevention of extreme heat injuries is largely dependent on the effectiveness of their protective clothing. The following meta-study examines contemporary literature to determine the usefulness of phase change materials (PCM’s) in improving the effectiveness of the current firefighter protective clothing (FFPC) model in order to better protect firefighters. The time- temperature for multiple PCM’s in environments with low, medium and high heat fluxes (taken as 2.5-5 kW/m2 for 700 seconds, 10-15 kW/m2 for 300 seconds and 20-40 kW/m2for 30 seconds respectively) were compared in terms of the rate of temperature increase and final temperature. The study found that PCM I produced the best temperature reduction in a low flux, PCM K did so in a medium flux, and PCM B did so in a high flux. The study also found that overall the PCMs were most effective in a low flux, therefore further study should be directed towards creating PCMs that are more effective in high-flux environments. Keywords: Phase Change Material; Fire Fighter Protective Clothing; Heat Flux

Thermal Requirement Analysis of Phase Change Protective Clothing in Low Temperature Environment

2013 ◽  
Vol 796 ◽  
pp. 649-652 ◽  
Author(s):  
Xiao Xiao Li ◽  
Yu Chai Sun ◽  
Jing Yu Xu ◽  
Rou Xi Chen
Keyword(s):  
Low Temperature ◽  
Phase Change ◽  
Protective Clothing ◽  
Phase Change Materials ◽  
Thermal Protection ◽  
Working Environment ◽  
Computational Method ◽  
Protective Material ◽  
Environment Temperature ◽  
Temperature Environment

In low temperature environment, the lack of a proper thermal protection can cause human body frostbite, or even cause death. In this paper, the computational method of theoretical relationship between the phase change materials content in protective clothing, protective time and the working environment temperature was proposed when took into account the comfort requirement of human bodies, clothing thermal properties and heat loss through clothing system. This theoretical model could be used to predict the relationship between the protective material content and the protection time of phase change protective clothing. Experimental results show good accordance with the theoretical prediction.

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