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Applications
Published in Raj P. Chhabra, CRC Handbook of Thermal Engineering Second Edition, 2017
Joshua D. Ramsey, Ken Bell, Ramesh K. Shah, Bengt Sundén, Zan Wu, Clement Kleinstreuer, Zelin Xu, D. Ian Wilson, Graham T. Polley, John A. Pearce, Kenneth R. Diller, Jonathan W. Valvano, David W. Yarbrough, Moncef Krarti, John Zhai, Jan Kośny, Christian K. Bach, Ian H. Bell, Craig R. Bradshaw, Eckhard A. Groll, Abhinav Krishna, Orkan Kurtulus, Margaret M. Mathison, Bryce Shaffer, Bin Yang, Xinye Zhang, Davide Ziviani, Robert F. Boehm, Anthony F. Mills, Santanu Bandyopadhyay, Shankar Narasimhan, Donald L. Fenton, Raj M. Manglik, Sameer Khandekar, Mario F. Trujillo, Rolf D. Reitz, Milind A. Jog, Prabhat Kumar, K.P. Sandeep, Sanjiv Sinha, Krishna Valavala, Jun Ma, Pradeep Lall, Harold R. Jacobs, Mangesh Chaudhari, Amit Agrawal, Robert J. Moffat, Tadhg O’Donovan, Jungho Kim, S.A. Sherif, Alan T. McDonald, Arturo Pacheco-Vega, Gerardo Diaz, Mihir Sen, K.T. Yang, Martine Rueff, Evelyne Mauret, Pawel Wawrzyniak, Ireneusz Zbicinski, Mariia Sobulska, P.S. Ghoshdastidar, Naveen Tiwari, Rajappa Tadepalli, Raj Ganesh S. Pala, Desh Bandhu Singh, G. N. Tiwari
Heat transfer internal to the body is due to the conductance which governs the flow of energy between the core, through the tissue, and to the surface. This transport process is governed significantly by peripheral blood flow, the core-skin temperature gradient, and the conductivity of the various body tissues. Transient blood perfusion provides an effective variable path of peripheral energy transport via convection between blood and tissue and countercurrent heat exchange between the arteries and the veins. Blood flow distribution is controlled according to metabolic needs of the body, local tissue temperature, and the need to maintain the appropriate core temperature. When the core becomes too hot, the blood vessels in the skin dilate to allow increased perfusion to the body surface. The blood is cooled by the environment, and the cooler blood is returned to the core. Increased blood flow to the skin surface also enables greater sweat production, adding to the cooling process. In contrast, when the core becomes too cold, blood flow to the skin is constricted to conserve the body’s internal energy. Sweating occurs when the arterial blood is elevated in temperature, causing the hypothalamus to increase nerve impulses to the sweat glands. Shivering, on the other hand, is an involuntary response of the skeletal muscles when passive body cooling exceeds metabolic energy production.79
How we experience indoor and outside climates
Published in Karl H.E. Kroemer, Fitting the Human, 2017
Normally, we replenish our bodies’ need for water from our food (which by volume is mostly water) and by taking sips of fluids°. However, sweating due to strenuous efforts, especially in a hot environment, can dehydrate the body. Dehydration of only one or two percent of body weight can critically affect the ability of the body to control its functions. (One percent of a 100 kg body mass converts to 1 L of water.) Maintaining a sufficient fluid level is easily done by frequently drinking small amounts of water. Sweating not only extracts water from the plasma but also carries some salt from the blood onto the skin. Generally, it is not necessary to add salt to drinking water since, in western diets, the salt in the food is more than sufficient to resupply the salt lost by sweating. Heat distress
Thermal Comfort
Published in Fergus Nicol, Michael Humphreys, Susan Roaf, Adaptive Thermal Comfort, 2012
Fergus Nicol, Michael Humphreys, Susan Roaf
When water evaporates it extracts a quantity of heat (the latent heat of evaporation) from its surroundings. Evaporation is an endothermic process – called so because energy, in the form of heat, is required to change water into a vapour. This cooling effect is very powerful, and cools the body and the air in its vicinity when we sweat. It is not the sweating that cools us but the evaporation of the sweat from the skin. Evaporative cooling becomes increasingly important as ambient operative temperatures rise through and above skin temperatures, from around 28°C through to 35°C, above which temperature the body relies solely on evaporation to cool itself.
The effect of dynamic friction with wet fabrics on skin wetness perception
Published in International Journal of Occupational Safety and Ergonomics, 2020
Zhaohua Zhang, Xiangning Tang, Jun Li, Wenyi Yang
Sweating is one of the important factors that help the human body to dissipate heat in a hot environment [1]. The interactions among skin, sweat and clothes may lead to discomfort and promote the growth of microbes, and even result in skin allergies [2,3]. In most cases, humans can sense wetness on the skin although they are not provided with specific receptors for this sensation. According to previous studies, the perception of wetness is a synthetic response through a complex multisensory integration of thermal (i.e., heat transfer) and tactile (i.e., mechanical pressure and friction) inputs, and a result of perceptual learning [4,5]. Therefore, it is hard to explain the discomfort caused by skin contacting wet fabrics without considering the heat, moisture transfer and surface performance of fabrics.
Effects of whey protein in carbohydrate-electrolyte drinks on post-exercise rehydration
Published in European Journal of Sport Science, 2018
Liang Li, Feng-Hua Sun, Wendy Ya-Jun Huang, Stephen Heung-Sang Wong
Sweating is a major evaporative water loss pathway during exercise, and dehydration often occurs after exercise due to excessive sweat loss (Passe, Horn, Stofan, Horswill, & Murray, 2007). Dehydration impairs exercise performance, muscular strength and cognitive functions (Popkin, D'Anci, & Rosenberg, 2010), so rapid and effective post-exercise rehydration are highly recommended to retain fluid balance (Shirreffs & Sawka, 2011). The volume and composition of ingested drinks are the main factors affecting post-exercise rehydration (Evans, James, Shirreffs, & Maughan, 2017; Shirreffs & Sawka, 2011). Commercially available sports drinks are more effective for rehydration than plain water because they contain water, carbohydrates (CHO) and electrolytes (Na+, K+, etc.), all of which are important for fluid balance in the body (Shirreffs, 2009; Wong & Chen, 2011).
Impulsive Behavior Detection System Using Machine Learning and IoT
Published in IETE Journal of Research, 2021
Soumya Jyoti Raychaudhuri, Soumya Manjunath, Chithra Priya Srinivasan, N. Swathi, S. Sushma, Nitin Bhushan K. N., C. Narendra Babu
Observations reveal that higher body temperatures and psychogenic fever arise in people who are prone to acute stress conditions [7]. Such elevated temperatures can be measured at the skin surface. The parameter variations cause continuous changes in the electrical conductance of the human skin and can be measured as an electro-dermal activity or Skin Conductance Response (SCR). Studies have shown that there are significant variations in the SCR when the human is exposed to stressful and relaxed situations [8]. Also, excessive sweating or hyperhydrosis has been observed in people suffering from anxiety disorders and sweat has been observed to be a very dependable parameter to detect stress [3].