Purpose – The purpose of this paper is to deal with performance verification of thermal insulation fillings that are used for outer clothes into cold environments. Thermal properties of filling materials (down and three sophisticated fillings) were tested under condition approaching real weather conditions in Middle Europe. Design/methodology/approach – In the paper, modern method of thermal resistance Rct measurement, by Sweating Guarded-Hotplate system, was compared with method of Technical University of Liberec (TUL method). The TUL method shows good results and it is applicable even at ambient temperatures below zero, which fully corresponds to real application of the insulation filling. Findings – Evaluation of fibre battings were carried out even at temperatures below the freezing point, which is important for simulation of actual application of these filling structures. The highest thermal resistance of goose down confirm that natural materials have their irreplaceable position, especially in application into clothes for extreme conditions. Research limitations/implications – There does not include effect of the humidity change on thermal insulation properties. It will be subject of further research of authors. Originality/value – The investigation of thermal insulation properties were carried out under conditions approaching real application of tested materials, namely, at low ambient temperature.
The main objective of the current research is the development of a new mathematical model for the prediction of compression pressure based on the incorporation of some new parameters. These new parameters include deformed width (wf), true stress ([Formula: see text]), true/logarithm strain ([Formula: see text]), true modulus of elasticity ([Formula: see text]), along with measurement of engineering stress ([Formula: see text]), engineering strain ([Formula: see text]) and engineering modulus of elasticity ([Formula: see text]) at ankle position. Various brands of compression socks comprising similar fibrous combinations, as well as knit type, were purchased. Initially they were hand washed, put on the leg for marking, marked in a square, sliced, and cut into rectangular strips. The rectangular cut strips were evaluated for force–elongation characterization at different strain values considering the requisite practical elongation values (circumferential difference between leg and sock at ankle portion). For pressure measurement, a Salzmann MST MK IV pressure measuring device using a standard-sized wooden leg (circumference = 240 mm) was used. For tensile evaluation, a Testometric tensile tester was used. In this research we developed the two mathematical models based on true Young’s modulus and engineering Young’s modulus were compared with Hooke’s law and Laplace’s law. The developed models were also compared with previously existing models statistically.
The experimental work presented in this study is related to the investigation of thermal protective performance of fi refi ghter clothing, which plays a pivotal role in the fi refi ghters' safety and performance. The fi refi ghter clothing usually consists of three layers, i.e. an outer shell, moisture barrier and thermal liner. Four samples were used for the purpose of this study. The samples were characterized on Alambeta for the evaluation of thermal resistance and thermal conductivity, respectively. Afterwards, the samples were evaluated on a thermal manikin "Maria" at room temperature to measure the insulation values. Moreover, air permeability was evaluated by using an air permeability tester. The samples were then analysed for their thermal protective behaviour in line with a lightly modifi ed ISO standard 12127, i.e. the samples were subjected toa150 °C heat plate at constant speed. In addition, transmitted heat fl ux density and percentage transmission factor of all samples were determined with the help of a radiant heat fl ux density machine at 10 kW/m 2 and 20 kW/m 2. It was concluded that sample 4 had higher thermal resistance and insulation values. The outer shell of sample 4 had lower air permeability values as compared to the outer shell of samples 1, 2 and 3. Similarly, the combination of the outer shell 4 and the thermal barrier 4 led to lower air permeability values as compared to the combination of the outer shell 1 and thermal barrier 1, outer shell 2 and thermal barrier 2, and outer shell 3 and thermal barrier 3. The rate of temperature rise in sample 4 occurred at a slower rate against the heated plate in comparison with samples 1, 2 and 3. Furthermore, sample 4 exhibited lower transmitted heat fl ux density and percentage transmission factor as compared to samples 1, 2 and 3.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.