Effect of Local Hand Thermal Insulation on Total and Local Comfort Under Different Levels of Body Heat Deficit

2005 ◽  
Author(s):  
Victor S. Koscheyev ◽  
Aitor Coca ◽  
Gloria R. Leon ◽  
Robert Treviño
Keyword(s):  
Thermal Insulation ◽  
Heat Deficit ◽  
Different Levels ◽  
Body Heat

Effects of Clothing Ventilative Designs on Thermal Insulation under Varying Wind Conditions

2011 ◽  
Vol 332-334 ◽  
pp. 1927-1930 ◽  
Author(s):  
Xiang Hui Zhang ◽  
Jun Li
Keyword(s):  
Experimental Investigation ◽  
Thermal Comfort ◽  
Thermal Insulation ◽  
The Body ◽  
Thermal Manikin ◽  
Clothing Insulation ◽  
Vertical Side ◽  
Wind Velocities ◽  
Heat And Moisture ◽  
Body Heat

This paper reports on an experimental investigation of the effects of clothing ventilative designs on thermal comfort measured in terms of thermal insulation. Eight T-shirts with varying areas and locations of mesh fabric were designed and produced for testing on a dry thermal manikin. Clothing thermal insulation of T-shirts was measured under three wind velocities: 0.5, 1 and 2m/s. The results showed that, the areas and locations of ventilation panels affect the total thermal insulation. The T-shirts with larger area of mesh fabric are preferable in terms of releasing more body heat. Among various designs tested, mesh fabrics applied at two vertical side seams can most effectively release heat and moisture from the body. Clothing insulation is also greatly affected by wind.

Changing physiological relationships in men under acute cold stress

1970 ◽  
Vol 48 (1) ◽  
pp. 1-10 ◽  
Author(s):  
James F. O'Hanlon Jr. ◽  
Steven M. Horvath
Keyword(s):  
Rectal Temperature ◽  
Heat Production ◽  
Cold Exposure ◽  
Heat Content ◽  
Body Temperatures ◽  
Older Subjects ◽  
Skin Temperatures ◽  
Different Levels ◽  
Body Heat ◽  
Thigh Temperature

Thirty-four men were exposed to 8 °C for 2 h. Their reactions were studied to indicate how physiological relationships change during exposure to cold. Measurements of various body temperatures, MST, MBT, body heat content (BHC), [Formula: see text], heat production, and heart rate (HR) were made before the onset of and periodically during cold exposure. Various skin temperatures fell to different levels while rectal temperature rose slightly, then fell 0.3 °C by the end of the exposure. BHC declined by 6%, [Formula: see text] nearly doubled, [Formula: see text] and heat production increased by 66 and 75% respectively, and HR changed little during cold exposure. Relationships which changed most significantly during cold exposure were those between MST and rectal temperature, certain skin temperatures and rectal temperature, [Formula: see text] (also heat production) and BHC, [Formula: see text] and rectal temperature, and finally, those between every body temperature and the age of the subjects. Relationships which also changed were those between finger and toe temperature as well as those between [Formula: see text] (also heat production) and each of the following: [Formula: see text], rectal temperature, thigh temperature, HR, and age. These results indicated that (1) temperature in the upper extremities was actively maintained at a higher level than temperature in the lower extremities, (2) increased metabolism became a progressively more effective adaptation than redistribution of blood volume, (3) subjects with the lowest BHC tended to increase their metabolism the most, (4) [Formula: see text] was inversely related to core temperature after the latter fell below normal, (5) HR was unrelated to the increase in [Formula: see text], (6) the usual inverse relationship between age and metabolism was not found in the cold, and finally, (7) older subjects generally tended to maintain higher body temperatures than younger subjects.

Impact of electrical heating on effective thermal Insulation of a multi-layered winter clothing system for optimal heating efficiency

2016 ◽  
Vol 28 (2) ◽  
Author(s):  
Huiju Park ◽  
Soo-kyung Hwang ◽  
Joo-Young Lee ◽  
Jintu Fan ◽  
Youngjin Jeong
Keyword(s):  
Ambient Temperature ◽  
Heat Loss ◽  
Thermal Insulation ◽  
Electric Heating ◽  
The Body ◽  
Electrical Heating ◽  
Thermal Manikin ◽  
Heating Unit ◽  
Heating Efficiency ◽  
Body Heat

Purpose This paper investigated the impact of the distance of the heating unit from the body in a multi-layered winter clothing system on effective thermal insulation and heating efficiency. Design/methodology/approach To identify changes in the thermal insulation and heating efficiency of electrical heating in different layers inside a winter clothing ensemble, a series of thermal manikin tests was conducted. A multi-layered winter ensemble with and without activation of a heating unit was tested on the thermal manikin under two different ambient temperature conditions (10°C and -5°C). Findings Results show that the effective thermal insulation of test ensembles increased by 5-7% with the activation of the heating unit compared to that without the activation. The closer the heating unit to the body, the higher the effective thermal insulation was in both ambient temperature conditions. This trend was more significant at lower ambient temperature. Research limitations/implications The results of this study indicate that providing electric heating next to the skin is the most effective in increasing effective thermal insulation and decreasing body heat loss in both ambient temperature (-5°C and 10°C). This trend was more remarkable in colder environment at -5°C of ambient temperature as evidenced by sharp decrease in heating efficiency and effective thermal insulation with an increase in distance between the manikin skin and heating unit at -5°C of ambient temperature compared to at 10°C of ambient temperature. Practical implications Based on the results, it is expected that proximity heating next to the skin, in cold environment, may reduce the weight and size of the battery for the heating unit because of the higher efficiency of electric heating and the potentially immediate perception of warmth supported by the greatest increase in effective thermal insulation, as well as the lowest heat loss that comes with activation of heating on the first layer in cold environment. Originality/value The finding of this study provides guidelines to sportswear designers, textile scientists, sports enthusiasts, and civilians who consider electric heating benefits for improved thermal comfort and safety in cold environments, especially in the areas of outdoor and winter sports and in military service. The results of this study indicate that providing electric heating next to the skin is the most effective in increasing effective thermal insulation and decreasing body heat loss in both ambient temperature (-5°C and 10°C).

scholarly journals Review: Radiation Heat Transfer Through Fire Fighter Protective Clothing

2017 ◽  
Vol 25 (0) ◽  
pp. 65-74 ◽  
Author(s):  
Jawad Naeem ◽  
Adnan Ahmed Mazari ◽  
Antonin Havelka
Keyword(s):  
Heat Flux ◽  
Thermal Insulation ◽  
Protective Clothing ◽  
Radiant Heat ◽  
Fire Fighter ◽  
Radiation Heat ◽  
Thermal Protective Performance ◽  
Firefighter Protective Clothing ◽  
Protective Performance ◽  
Different Levels

A fire fighter garment is multilayer protective clothing with an outer shell, moisture barrier and thermal barrier, respectively. Fire fighters encounter different levels of radiant heat flux while performing their duties. This review study acknowledges the importance and performance of fire fighter protective clothing when subjected to a low level of radiation heat flux as well as the influence of air gaps and their respective position on the thermal insulation behaviour of multilayer protective clothing. Thermal insulation plays a vital role in the thermal comfort and protective performance of fire fighter protective clothing (FFPC). The main emphasis of this study was to analyse the performance of FFPC under different levels of radiant heat flux and how the exposure time of fire fighters can be enhanced before acquiring burn injuries. The preliminary portion of this study deals with the modes of heat transportation within textile fabrics, the mechanism of thermal equilibrium of the human body and the thermal protective performance of firefighter protective clothing. The middle  portion is concerned with thermal insulation and prediction of the physiological load of  FFPC. The last section deals with numerical models of heat transmission through firefighter protective clothing assemblies and possible utility of aerogels and Phase Change Materials  (PCMs) for enhancing the thermal protective performance of FFPC.

Thermal Insulators' Performances in Simulated Mars Environment

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Diego Scaccabarozzi ◽  
Bortolino Saggin ◽  
Marco Tarabini
Keyword(s):  
Thermal Conductivity ◽  
Thermal Insulation ◽  
Thermal Control ◽  
Experimental Characterization ◽  
Hot Plate ◽  
Carbon Dioxide Atmosphere ◽  
Different Levels ◽  
Plate Apparatus ◽  
Gas Pressures

This paper describes the experimental characterization of the thermal insulation properties of a multilayer insulator (MLI) and of an aerogel. Materials characterization was performed to optimize the thermal control design of a small interferometer devoted to planetary observation. In order to simulate the Martian environment, tests were performed in a carbon dioxide atmosphere, with pressures between 10 and 104 Pa and temperatures from 193 to 353 K. MLI was tested at different levels of layers compression to investigate thermal insulation changes deriving from the constraining of the mechanical structure. The thermal conductivity was measured with a purposely designed guarded hot plate apparatus. Results showed that the aerogel exhibits a lower thermal conductivity for gas pressures larger than 100 Pa and that the layer compression of the MLIs does not affect the heat conduction for gas pressures above 103 Pa.

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

Immunoenzymatic demonstration of the simultaneous presence of transferrin, hemopexin and albumin in a same hepatocyte and their ultrastructural localization

1978 ◽  
Vol 36 (2) ◽  
pp. 88-89
Author(s):  
M. Kraemer ◽  
J. Foucrier ◽  
J. Vassy ◽  
M.T. Chalumeau
Keyword(s):  
Plasma Proteins ◽  
Rat Hepatocytes ◽  
Ultrastructural Localization ◽  
Carrier Proteins ◽  
Normal Cells ◽  
Adult Rat ◽  
Adult Rat Hepatocytes ◽  
Monospecific Antisera ◽  
Different Levels

Some authors using immunofluorescent techniques had already suggested that some hepatocytes are able to synthetize several plasma proteins. In vitro studies on normal cells or on cells issued of murine hepatomas raise the same conclusion. These works could be indications of an hepatocyte functionnal non-specialization, meanwhile the authors never give direct topographic proofs suitable with this hypothesis.The use of immunoenzymatic techniques after obtention of monospecific antisera had seemed to us useful to bring forward a better knowledge of this problem. We have studied three carrier proteins (transferrin = Tf, hemopexin = Hx, albumin = Alb) operating at different levels in iron metabolism by demonstrating and localizing the adult rat hepatocytes involved in their synthesis.Immunological, histological and ultrastructural methods have been described in a previous work.

Memory Processes, Aging, Cognitive Decline, and Neurodegenerative Diseases

2006 ◽  
Vol 11 (4) ◽  
pp. 304-311 ◽  
Author(s):  
Lars-Göran Nilsson
Keyword(s):  
Cognitive Impairment ◽  
Cognitive Decline ◽  
Neurodegenerative Disease ◽  
Genetic Markers ◽  
Brain Activity ◽  
Memory Performance ◽  
Modeling And Simulations ◽  
Aging And Health ◽  
Explained Variance ◽  
Different Levels

This paper presents four domains of markers that have been found to predict later cognitive impairment and neurodegenerative disease. These four domains are (1) data patterns of memory performance, (2) cardiovascular factors, (3) genetic markers, and (4) brain activity. The critical features of each domain are illustrated with data from the longitudinal Betula Study on memory, aging, and health ( Nilsson et al., 1997 ; Nilsson et al., 2004 ). Up to now, early signs regarding these domains have been examined one by one and it has been found that they are associated with later cognitive impairment and neurodegenerative disease. However, it was also found that each marker accounts for only a very small part of the total variance, implying that single markers should not be used as predictors for cognitive decline or neurodegenerative disease. It is discussed whether modeling and simulations should be used as tools to combine markers at different levels to increase the amount of explained variance.

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