Статті в журналах: "Sweat Evaporation"

1

Guan, Manhao, Simon Annaheim, Martin Camenzind, Jun Li, Sumit Mandal, Agnes Psikuta, and René Michel Rossi. "Moisture transfer of the clothing–human body system during continuous sweating under radiant heat." Textile Research Journal 89, no. 21-22 (March 19, 2019): 4537–53. http://dx.doi.org/10.1177/0040517519835767.

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Mass transfer due to perspired moisture in a clothing system is critical for the understanding of thermo-physiology and thermal protection of a clothed body. Previous studies usually investigated moisture transfer without considering the effect of liquid sweating or external heat hazards. To understand the mechanisms of sweat evaporation, accumulation and dripping with continuous sweating under radiant heat, a multi-phase experiment was designed with a sweating Torso. The concept of clothed wettedness was proposed to understand sweat evaporation of the clothed body. Results showed that the evaporation rate of the clothed body increased with increasing perspiration rate and the rate increase can be explained by the material properties (e.g., material composition, hydrophilicity and evaporative resistance ([Formula: see text])), which affected the sweat accumulation ability. Results also demonstrated a dual relationship of [Formula: see text] with the evaporation rate of the clothed body. Firstly, the evaporation rate was increased for greater [Formula: see text] due to the higher moisture accumulation. Secondly, when [Formula: see text] exceeded a certain value, the evaporation rate decreased with greater [Formula: see text] due to the reduction in the mass transfer coefficient. For radiant heat exposure, evaporated sweat may condense on the skin surface, decreasing the evaporation rate and increasing the dripping rate. The sweat transfer process was also investigated in detail by the combined analysis of the sweat transfer rate and the evaporative cooling efficiency. This study provides insights into how continuous liquid sweat transfers and evaporates in the clothed body and its interaction with clothing material and environment radiant heat, contributing to the understanding of thermo-physiological burden and thermal protection of the clothed body with intensive activities.

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2

Shrestha, Dev Chandra, Saraswati Acharya, and Dil Bahadur Gurung. "A Finite Element Approach to Evaluate Thermoregulation in the Human Body due to the Effects of Sweat Evaporation during Cooking, Cleaning, and Walking." Mathematical Problems in Engineering 2021 (May 26, 2021): 1–14. http://dx.doi.org/10.1155/2021/5539151.

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Sweat evaporation is the principal process of dissipating heat energy in a hot environment and during activities. Sweat loss is significantly affected by the level of energy expenditure, hormones, and the number of sweat glands. The thickness of the skin layer plays a vital role to maintain body temperature. The rate of sweat evaporation varies with ambient temperature and activity level. On increasing both metabolism and ambient temperature, sweat rate loss also increases and controls the body in the thermoregulatory system. The evaporative sweat release rate has a linear behavior. The appropriate physical and physiological parameters that affect thermoregulation have been incorporated into the model. The study presents the temperature distribution in three layers: epidermis, dermis, and subcutaneous tissue (SST) of the human dermal parts during cooking, cleaning, and walking. The solution is obtained by using the finite element method. The results demonstrate that the body mechanism keeps the body in thermoregulation by increasing the sweat evaporation rate exhibited by increasing the ambient temperature and metabolism during strenuous activities.

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3

Cramer, Matthew N., and Ollie Jay. "Compensatory hyperhidrosis following thoracic sympathectomy: a biophysical rationale." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 302, no. 3 (February 1, 2012): R352—R356. http://dx.doi.org/10.1152/ajpregu.00419.2011.

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A side-effect of endoscopic thoracic sympathectomy (ETS) is compensatory hyperhidrosis (CH), characterized by excessive sweating from skin areas with intact sudomotor function. The physiological mechanism of CH is unknown, but may represent an augmented local sweat rate from skin areas with uninterrupted sympathetic innervation based on evaporative heat balance requirements. For a given combination of activity and climate, the same absolute amount of evaporation (if any) is needed to balance the rate of metabolic heat production both pre- and post-ETS. However, the rate of local sweating per unit of skin surface area with intact sudomotor activity must be greater post-ETS as evaporation must be derived from a smaller skin surface area. Under conditions with high evaporative requirements, greater degradations in sweating efficiency associated with an increased dripping of sweat should also occur post-ETS, further pronouncing the sweat rate required for heat balance. In conclusion, in addition to the potential role of psychological stimuli for increased sudomotor activity, the existence of CH post-ETS can be described by the interplay between fundamental thermoregulatory physiology and altered heat balance biophysics and does not require a postoperative alteration in physiological control.

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4

Chen, Xiao-Ming, Yong-Jiang Li, Dan Han, Hui-Chao Zhu, Chun-Dong Xue, Hsiang-Chen Chui, Tun Cao, and Kai-Rong Qin. "A Capillary-Evaporation Micropump for Real-Time Sweat Rate Monitoring with an Electrochemical Sensor." Micromachines 10, no. 7 (July 7, 2019): 457. http://dx.doi.org/10.3390/mi10070457.

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Sweat collection and real time monitoring of sweat rate play essential roles in physiology monitoring and assessment of an athlete’s performance during exercise. In this paper, we report a micropump for sweat simulant collection based on the capillary–evaporation effect. An electrochemical sensor is integrated into the micropump, which monitors the flow rate in real-time by detecting the current using three electrodes. The evaporation rate from micropore array, equivalent to the sweat rate, was theoretically and numerically investigated. The designed micropump yields the maximum collection rate as high as 0.235 μ L/min. In addition, the collection capability of the micropump was validated experimentally; the flow rate through the microchannel was further detected in real-time with the electrochemical sensor. The experimental maximum collection rate showed good consistency with the theoretical data. Our proposed device shows the potential for sweat collection and real-time monitoring of sweat rate, which is a promising candidate for being a wearable platform for real-time physiology and performance monitoring during exercise.

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5

Otomasu, Kinuyo, Masaki Yamauchi, Nobu Ohwatari, Takaaki Matsumoto, Katsuhiko Tsuchiya, and Mitsuo Kosaka. "Analysis of sweat evaporation from clothing materials by the ventilated sweat capsule method." European Journal of Applied Physiology 76, no. 1 (June 1, 1997): 1–7. http://dx.doi.org/10.1007/s004210050205.

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6

Lolla, Venkata Yashasvi, Pranav Shukla, Stevan D. Jones, and Jonathan B. Boreyko. "Evaporation-Induced Clogging of an Artificial Sweat Duct." ACS Applied Materials & Interfaces 12, no. 47 (November 16, 2020): 53403–8. http://dx.doi.org/10.1021/acsami.0c13493.

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7

Shimazaki, Yasuhiro, and Shunpei Katsuta. "Spatiotemporal sweat evaporation and evaporative cooling in thermal environments determined from wearable sensors." Applied Thermal Engineering 163 (December 2019): 114422. http://dx.doi.org/10.1016/j.applthermaleng.2019.114422.

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8

Zhao, Mengmeng, Chuansi Gao, Faming Wang, Kalev Kuklane, Ingvar Holmér, and Jun Li. "The torso cooling of vests incorporated with phase change materials: a sweat evaporation perspective." Textile Research Journal 83, no. 4 (September 27, 2012): 418–25. http://dx.doi.org/10.1177/0040517512460294.

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Cooling vests incorporated with phase change materials (PCMs) add extra insulation and restrict sweat evaporation. It is still unclear how much cooling benefit they can provide. The aim of this study was to investigate the torso cooling of the PCM vests in two hot environments: hot humid (HH, 34°C, 75% relative humidity (RH)) and hot dry (HD, 34°C, 37% RH). A pre-wetted torso fabric skin was used to simulate torso sweating on a thermal manikin. Three cooling vests incorporated with three melting temperatures ( Tm) of PCMs were tested ( Tm = 21°C, Tm = 24°C and Tm = 28°C). They were worn under a military ensemble (total thermal insulation 1.60 clo; evaporative resistance 0.0516 kPaċm2/W), respectively. In a HH environment all the three cooling vests provided effective torso cooling; in a HD environment the cooling benefit was negative. In both environmental conditions, the evaporative cooling was greatly restricted by the cooling vests. The study indicated that when wearing the protective clothing with the relatively low evaporative resistance and when sweat production was high, the cooling vests were effective in a HH environment, but not in a HD environment.

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9

Bariya, Mallika, Lu Li, Rahul Ghattamaneni, Christine Heera Ahn, Hnin Yin Yin Nyein, Li-Chia Tai, and Ali Javey. "Glove-based sensors for multimodal monitoring of natural sweat." Science Advances 6, no. 35 (August 2020): eabb8308. http://dx.doi.org/10.1126/sciadv.abb8308.

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Sweat sensors targeting exercise or chemically induced sweat have shown promise for noninvasive health monitoring. Natural thermoregulatory sweat is an attractive alternative as it can be accessed during routine and sedentary activity without impeding user lifestyles and potentially preserves correlations between sweat and blood biomarkers. We present simple glove-based sensors to accumulate natural sweat with minimal evaporation, capitalizing on high sweat gland densities to collect hundreds of microliters in just 30 min without active sweat stimulation. Sensing electrodes are patterned on nitrile gloves and finger cots for in situ detection of diverse biomarkers, including electrolytes and xenobiotics, and multiple gloves or cots are worn in sequence to track overarching analyte dynamics. Direct integration of sensors into gloves represents a simple and low-overhead scheme for natural sweat analysis, enabling sweat-based physiological monitoring to become practical and routine without requiring highly complex or miniaturized components for analyte collection and signal transduction.

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10

Hsing, Wen Hao, Wei Jay Yang, and Ya Lan Hsing. "Far-Infrared Emission of Filled Fabric by Sweat." Advanced Materials Research 287-290 (July 2011): 2610–13. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.2610.

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In this experiment, use of far infrared filled fabric of instillation of sweat on the man the purpose of detecting artificial sweat on the far-infrared radiation rate of fiber influence and change the fiber type, weight, the proportion of artificial sweat to detect far-infrared radiation rate of thick fabrics change. The results showed that the infrared fiber’s radiation rate of cotton fiber to be higher about 0.07. Far-infrared on a thick layer of fabric at the instillation of 3% weight, 6% of the weight, 9% of the weight of artificial sweat, its far-infrared radiation rate would be the relationship between the rapid decline due to sweat, but with the artificial sweat evaporation, radiation will slow the rate of rise, Another far-infrared fiber samples of 3g weights repeated titration sweat, the far-infrared fiber samples of the far-infrared radiation rate will be increased about 0.005 ~ 0.007

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11

Reeder, Jonathan T., Jungil Choi, Yeguang Xue, Philipp Gutruf, Justin Hanson, Mark Liu, Tyler Ray, et al. "Waterproof, electronics-enabled, epidermal microfluidic devices for sweat collection, biomarker analysis, and thermography in aquatic settings." Science Advances 5, no. 1 (January 2019): eaau6356. http://dx.doi.org/10.1126/sciadv.aau6356.

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Noninvasive, in situ biochemical monitoring of physiological status, via the use of sweat, could enable new forms of health care diagnostics and personalized hydration strategies. Recent advances in sweat collection and sensing technologies offer powerful capabilities, but they are not effective for use in extreme situations such as aquatic or arid environments, because of unique challenges in eliminating interference/contamination from surrounding water, maintaining robust adhesion in the presence of viscous drag forces and/or vigorous motion, and preventing evaporation of collected sweat. This paper introduces materials and designs for waterproof, epidermal, microfluidic and electronic systems that adhere to the skin to enable capture, storage, and analysis of sweat, even while fully underwater. Field trials demonstrate the ability of these devices to collect quantitative in situ measurements of local sweat chloride concentration, local sweat loss (and sweat rate), and skin temperature during vigorous physical activity in controlled, indoor conditions and in open-ocean swimming.

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12

Kenney, W. L., D. A. Lewis, D. E. Hyde, T. S. Dyksterhouse, C. G. Armstrong, S. R. Fowler, and D. A. Williams. "Physiologically derived critical evaporative coefficients for protective clothing ensembles." Journal of Applied Physiology 63, no. 3 (September 1, 1987): 1095–99. http://dx.doi.org/10.1152/jappl.1987.63.3.1095.

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When work is performed in heavy clothing, evaporation of sweat from the skin to the environment is limited by layers of wet clothing and air. The magnitude of decrement in evaporative cooling is a function of the clothing's resistance to permeation of water vapor. A physiological approach has been used to derive effective evaporative coefficients (he) which define this ability to evaporate sweat. We refined this approach by correcting the critical effective evaporative coefficient (K for sweating efficiency (Ke,eta') since only a portion of the sweat produced under such conditions is evaporated through the clothing. Six acclimated men and women walked at 30% maximal O2 consumption (150–200 W.m-2) at a constant dry bulb temperature as ambient water vapor pressure was systematically increased 1 Torr every 10 min. Critical pressure was defined as the partial pressure of water vapor (Pw) at which thermal balance could no longer be maintained and rectal temperature rose sharply. Each test was performed in various clothing ensembles ranging from cotton shirt and pants to “impermeable” suits. This approach was used to derive he by solving the general heat balance equation, M - W +/- (R + C) = w.he.(Psk - Pw), where M is metabolic heat production, W is external work, R is radiant heat exchange, C is convective heat transfer, w is skin wettedness, and Psk is water vapor pressure of fully wet skin.(ABSTRACT TRUNCATED AT 250 WORDS)

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13

Serup, J., and I. Rasmussen. "Dry hands in scleroderma. Including studies of sweat gland function in healthy individuals." Acta Dermato-Venereologica 65, no. 5 (September 1, 1985): 419–23. http://dx.doi.org/10.2340/0001555565419423.

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Complaints of dry hands were evaluated in 68 patients with generalized scleroderma (GS) and 66 healthy individuals (HI) for comparison. Studies included evaporimetry of the hands and forearms as performed under physiological conditions indicating sweat gland function. Complaints of dry hands were more frequent (p less than 0.001) in GS (71%) than in HI (32%) as was the use of emollients (68% and 32% respectively). Evaporimetry at eight different locations (flexor and extensor aspects of middle phalanx, proximal phalanx, hand and forearm) showed decreased evaporation (p less than 0.01 and p less than 0.001) in GS. However, there was no difference in evaporation between patients complaining of dry hands and patients without complaints. In a few locations the evaporation was negatively correlated (r from -0.287 to -0.376, p less than 0.05 and p less than 0.01) to the duration of GS and positively correlated to parameters of cutaneous thickening (ultrasound measurement skin thickness r = 0.252, p less than 0.05; ring size r = 0.294, p less than 0.05). In the group of healthy individuals complaints of dryness was more frequent (p less than 0.05) in females (39%) than in males (7%), and females also used emollients more frequently (p less than 0.01). HI complaining of dryness had similar evaporation as HI with no complaints. Physiological evaporation was negatively correlated to age, in particular in the palm and volar side of fingers (r from -0.424 to -0.454, p less than 0.01 and p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

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14

Ayling, J. H. "Regional rates of sweat evaporation during leg and arm cycling." British Journal of Sports Medicine 20, no. 1 (March 1, 1986): 35–37. http://dx.doi.org/10.1136/bjsm.20.1.35.

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15

LIGHT, I. M., M. G. GIBSON, and A. I. AVERY. "Sweat evaporation and thermal comfort wearing helicopter passenger immersion suits." Ergonomics 30, no. 5 (May 1987): 793–803. http://dx.doi.org/10.1080/00140138708969768.

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16

Liu, Song-Rui, Xiao-Qun Dai, and Yan Hong. "Prediction of the water evaporation rate of wet textile materials in a pre-defined environment." International Journal of Clothing Science and Technology 32, no. 3 (January 8, 2020): 356–65. http://dx.doi.org/10.1108/ijcst-06-2019-0077.

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Purpose The water evaporation rate (WER) is not only crucial for fabric drying, but also an important parameter affecting cooling from a body wearing sweat wetted clothing. The purpose of this paper is to predict the WERs of wet textile materials in a pre-defined environment. Design/methodology/approach The maximum water evaporation rate (WERmax) from a saturated surface in a pre-defined environment was first predicted based on the Lewis relationship between the evaporative and the convective heat transfer in this paper. The prediction results were validated by the comparisons with experimental measurements in various environments obtained in this paper and reported in the literature. Findings Experiment results show that the ratios of WERs to WERmax are lower than 100 percent but higher than 50 percent, which confirmed that the prediction of WERmax is reliable. The temperature decrease of the wet material surface due to evaporation was considered to account for the difference between measured WERs and the WERmax, and the WER variation among materials. The lower ratios of WERs to WERmax in the higher wind condition were speculated to be due to the greater temperature decrease caused by the increased evaporation. Practical implications It provides a reliable way to obtain both WERmax and WER (WERmax multiplied by a proper ratio), which can be useful in clothing physiological modeling to predict clothing comfort. Originality/value This study contributes to the understanding of the evaporation process of textile materials.

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17

Herten, Anne, Robert Csapo, Philipp Kofler, Giuliamarta Bottoni, Michael Hasler, Thomas Bechtold, and Werner Nachbauer. "Effects of functional shirts with different fiber compositions on thermoregulation in well-trained runners." Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology 231, no. 2 (April 24, 2016): 75–82. http://dx.doi.org/10.1177/1754337116632418.

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This study aimed to investigate the effects of two functional sport shirts with different fiber compositions (polyester: 100% polyester vs polyester–lyocell combination: 67%–33%) on thermoregulation and wearing comfort during treadmill walking at an average intensity under moderate environmental conditions. It was hypothesized that the hydrophilic lyocell fibers would benefit sweat evaporation and, thus, provide a superior cooling effect. Using a repeated-measures study design, core, surface and between skin-and-shirt temperatures were measured in 11 men while wearing either the polyester or polyester–lyocell shirt. Additionally, sweat loss, heart rate and subjective perception of comfort were determined. In spite of significantly greater sweat production, relative humidity was lower with the polyester–lyocell shirt. In the later phases of the walking intervention, the temperatures were consistently higher with polyester–lyocell, although between-shirt differences failed to reach significance. These results suggest that greater water retention limits the thermoregulatory efficiency of cellulosic fibers when excessive sweat production occurs.

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18

Zhang, Qian, Buyang Li, and Weiwei Sun. "Heat and sweat transport through clothing assemblies with phase changes, condensation/evaporation and absorption." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 467, no. 2136 (July 20, 2011): 3469–89. http://dx.doi.org/10.1098/rspa.2011.0125.

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The paper is concerned with the heat and sweat transport in porous textile media with complex phase changes, which is described as a non-isothermal, multi-phase and multi-component fluid flow and governed by a nonlinear, degenerate and strongly coupled parabolic system. The phase change, condensation/evaporation and fibre absorption, play an important role in the design of functional clothing. In this paper, we present some more precise formulations on condensation/evaporation, fibre absorption and heat capacity to maintain the physical conservation of mass and energy. A typical clothing assembly with a hydrophobic batting material and two different types of cover is investigated numerically. Numerical results show that for the hydrophobic material, the evaporation and condensation zones arise simultaneously in the batting area and that the proposed formulations are more realistic to describe the phase change. Existence and uniqueness of a classical positive solution for the incompressible model are also proved.

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19

Aich, Tarkeswar. "Uremic frost- A rare skin manifestation of severe kidney disease." Journal of Medical Research 5, no. 6 (January 4, 2019): 208–9. http://dx.doi.org/10.31254/jmr.2019.5602.

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Uremic frost is a rare dermatological manifestation of severe azotemia. It is rarely seen today because of early dialytic intervention. It occurs when high concentration of urea and other nitrogenous waste products accumulate in the sweat and then crystallizes as deposit on the skin after evaporation in a process called uridrosis or urinous sweat. Its a sign of impending renal failure and portends bad prognosis. Involvement of urea transporters may have a role in its development. Damage to the cutaneous microvasculature, eccrine sweat and sebaceous glands may be responsible for the high level of urea accumulation on skin. The test to analyze that the crystalline material is urea or nitrogenous waste products, the scrapings of the sample can be dilutad in normal saline and then tested for elevated urea nitrogen level. No specific therapy except correcting the underlying etiology

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20

Kakitsuba, Naoshi, and Tetsuo Katsuura. "Direct Determination of Local Evaporative Heat Transfer Coefficientsby Simultaneous Measurement of Local Sweat Rate and Evaporation Rate." Journal of the Human-Environment System 1, no. 1 (1997): 93–97. http://dx.doi.org/10.1618/jhes.1.93.

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21

Budd, GM, JR Brotherhood, AL Hendrie, SE Jeffery, FA Beasley, BP Costin, W. Zhien, et al. "Project Aquarius 13. The Thermal Burden of High Insulation and Encapsulation in Wildland Firefighters' Clothing." International Journal of Wildland Fire 7, no. 2 (1997): 207. http://dx.doi.org/10.1071/wf9970207.

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Light, heavy, and encapsulating clothing were compared in a climatic chamber during 60 minutes of moderate exercise (energy expenditure 382-464 W) in warm, dry conditions with no added radiant heat (air and mean radiant temperature 30°C, relative humidity 33 %, air velocity 0.5 m s-1). The results showed that high insulation and reduced ventilation restricted the evaporation of sweat and thus hindered the dissipation of metabolic heat. These adverse effects were apparent in (1) a reduced cooling efficiency of sweat and hence a higher sweat rate; (2) increased heat storage, cardiovascular strain, discomfort, and fatigue; and (3) a failure to attain thermal equilibrium even after 60 minutes of work. Comparison with the effects of fire, previously reported, on lightly dressed firefighters showed that the above penalties would outweigh any benefit that extra insulation or encapsulation could confer during wildland fire suppression with hand tools.

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22

Salvesen, R., T. Sand, and O. Sjaastad. "Cluster Headache: Combined Assessment with Pupillometry and Evaporimetry." Cephalalgia 8, no. 3 (September 1988): 211–18. http://dx.doi.org/10.1046/j.1468-2982.1988.0803211.x.

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Twenty-nine patients with cluster headache have been examined with the pupillometer and the evaporimeter. Pupils were dilated by sympathicomimetic drugs instilled into the conjunctival sacs, and responses of the two sides were compared. Forehead sweating was stimulated by body heating and by pilocarpine injection, and sweat evaporation on the two sides was compared. Most patients demonstrated the known patterns of hyposecretion on heating, of pilocarpine supersensitivity, and of deficient pupillary dilatation on OH-amphetamine stimulation on the symptomatic side and a supersensitivity of this pupil to phenylephrine. There were deviations from the rule for all methods of testing. Sixteen patients demonstrated a typical supersensitivity response of the pupil and of the sweat glands on the symptomatic side. Six patients had no such response, and seven patients had a discrepancy between the pupillary and the sweat gland response to stimulation, supersensitivity being present in one system only. There was a high degree of concordance between the results of the various methods of examination.

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23

Gerrett, Nicola, Katy Griggs, Bernard Redortier, Thomas Voelcker, Narihiko Kondo, and George Havenith. "Sweat from gland to skin surface: production, transport, and skin absorption." Journal of Applied Physiology 125, no. 2 (August 1, 2018): 459–69. http://dx.doi.org/10.1152/japplphysiol.00872.2017.

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By combining galvanic skin conductance (GSC), stratum corneum hydration (HYD) and regional surface sweat rate (RSR) measurements at the arm, thigh, back and chest, we closely monitored the passage of sweat from gland to skin surface. Through a varied exercise-rest protocol, sweating was increased slowly and decreased in 16 male and female human participants (25.3 ± 4.7 yr, 174.6 ± 10.1 cm, 71.3 ± 12.0 kg, 53.0 ± 6.8 ml·kg−1·min−1). ∆GSC and HYD increased before RSR, indicating pre-secretory sweat gland activity and skin hydration. ∆GSC and HYD typically increased concomitantly during rest in a warm environment (30.1 ± 1.0°C, 30.0 ± 4.7% relative humidity) and only at the arm did ∆GSC increase before an increase in HYD. HYD increased before RSR, before sweat was visible on the skin, but not to full saturation, contradicting earlier hypotheses. Maximal skin hydration did occur, as demonstrated by a plateau in all regions. Post exercise rest resulted in a rapid decrease in HYD and RSR but a delayed decline in ∆GSC. Evidence for reabsorption of surface sweat into the skin following a decline in sweating, as hypothesized in the literature, was not found. This suggests that skin surface sweat, after sweating is decreased, may not diffuse back into the dermis, but is only evaporated. These data, showing distinctly different responses for the three measured variables, provide useful information about the fate of sweat from gland to surface that is relevant across numerous research fields (e.g., thermoregulation, dermatology, ergonomics and material design). NEW & NOTEWORTHY After sweat gland stimulation, sweat travels through the duct, penetrating the epidermis before appearing on the skin surface. We found that only submaximal stratum corneum hydration was required before surface sweating occurred. However, full hydration occurred only once sweat was on the surface. Once sweating reduces, surface sweat evaporation continues, but there is a delayed drying of the skin. This information is relevant across various research fields, including environmental ergonomics, dermatology, thermoregulation, and skin-interface interactions.

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24

Gagnon, Daniel, Ollie Jay, and Glen P. Kenny. "The evaporative requirement for heat balance determines whole-body sweat rate during exercise under conditions permitting full evaporation." Journal of Physiology 591, no. 11 (April 5, 2013): 2925–35. http://dx.doi.org/10.1113/jphysiol.2012.248823.

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25

KAKITSUBA, Naoshi, and Tetsuo KATSUURA. "MEASUREMENTS OF LOCAL SWEAT RATES AND EVAPORATION RATES AND THE DIRECT DETERMINATION OF LOCAL EVAPORATIVE HEAT TRANSFER COEFFICIENTS." Journal of Architecture and Planning (Transactions of AIJ) 59, no. 464 (1994): 65–70. http://dx.doi.org/10.3130/aija.59.65_3.

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26

Gonzalez, Richard R., Samuel N. Cheuvront, Brett R. Ely, Daniel S. Moran, Amir Hadid, Thomas L. Endrusick, and Michael N. Sawka. "Sweat rate prediction equations for outdoor exercise with transient solar radiation." Journal of Applied Physiology 112, no. 8 (April 15, 2012): 1300–1310. http://dx.doi.org/10.1152/japplphysiol.01056.2011.

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We investigated the validity of employing a fuzzy piecewise prediction equation (PW) [Gonzalez et al. J Appl Physiol 107: 379–388, 2009] defined by sweat rate (msw, g·m−2·h−1) = 147 + 1.527·(Ereq) − 0.87·(Emax), which integrates evaporation required (Ereq) and the maximum evaporative capacity of the environment (Emax). Heat exchange and physiological responses were determined throughout the trials. Environmental conditions were ambient temperature (Ta) = 16–26°C, relative humidity (RH) = 51–55%, and wind speed ( V) = 0.5–1.5 m/s. Volunteers wore military fatigues [clothing evaporative potential (im/clo) = 0.33] and carried loads (15–31 kg) while marching 14–37 km over variable terrains either at night ( N = 77, trials 1–5) or night with increasing daylight ( N = 33, trials 6 and 7). PW was modified ( Ṗw,sol) for transient solar radiation (Rsol, W) determined from measured solar loads and verified in trials 6 and 7. PW provided a valid msw prediction during night trials ( 1–5) matching previous laboratory values and verified by bootstrap correlation (rbs of 0.81, SE ± 0.014, SEE = ± 69.2 g·m−2·h−1). For trials 6 and 7, Ereq and Emax components included Rsol applying a modified equation Ṗw,sol, in which msw = 147 + 1.527·(Ereq,sol) − 0.87·(Emax). Linear prediction of msw = 0.72· Ṗw,sol + 135 ( N = 33) was validated ( R2 = 0.92; SEE = ±33.8 g·m−2·h−1) with PW β-coefficients unaltered during field marches between 16°C and 26°C Ta for msw ≤ 700 g·m−2·h−1. PW was additionally derived for cool laboratory/night conditions (Ta < 20°C) in which Ereq is low but Emax is high, as: PW,cool (g·m−2·h−1) = 350 + 1.527·Ereq − 0.87·Emax. These sweat prediction equations allow valid tools for civilian, sports, and military medicine communities to predict water needs during a variety of heat stress/exercise conditions.

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Falk, Bareket, and Raffy Dotan. "Children’s thermoregulation during exercise in the heat — a revisit." Applied Physiology, Nutrition, and Metabolism 33, no. 2 (April 2008): 420–27. http://dx.doi.org/10.1139/h07-185.

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The review revisits some child–adult differences relevant to thermoregulation and offers alternatives to accepted interpretations. Morphologically, children have a higher body surface area to mass ratio — a major factor in “dry” heat dissipation and effective sweat evaporation. Locomotion-wise, children are less economical than adults, producing more heat per unit body mass. Additionally, children need to divert a greater proportion of their cardiac output to the skin under heat stress. Thus, a larger proportion of their cardiac output is shunted away from the body’s core and working muscles — particularly in hot conditions. Finally, under all environmental conditions and allometric comparisons, children's sweating rates are lower than those of adults. The differences appear to suggest thermoregulatory inferiority, but no epidemiological data show higher heat-injury rates in children, even during heat waves. We suggest that children employ a different thermoregulatory strategy. In extreme temperatures, they may indeed be more vulnerable, but under most ambient conditions they are not necessarily inferior to adults. Children rely more on dry heat dissipation by their larger relative skin surface area than on evaporative heat loss. This also enables them to evaporate sweat more efficiently with the added bonus of conserving water better than adults.

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Lund, R. J., A. J. Guthrie, H. J. Mostert, C. W. Travers, J. P. Nurton, and D. J. Adamson. "Effect of three different warm-up regimens on heat balance and oxygen consumption of thoroughbred horses." Journal of Applied Physiology 80, no. 6 (June 1, 1996): 2190–97. http://dx.doi.org/10.1152/jappl.1996.80.6.2190.

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Horses were exercised at 105% of their maximal O2 uptake until fatigued after three different warm-up regimens (no warm-up, a light warm-up, and a warm-up until the central venous temperature was > 39.5 degrees C) to assess the effect of the warm-up on the various avenues of heat loss. Approximately 12.79, 15.10, and 18.40 MJ of heat were generated in response to the warm-up and exercise after the three different warm-up regimens, respectively. Of the heat generated, 17.5, 17.2, and 17.4% remained as stored heat after 20 min of active recovery. Heat loss from the respiratory system was 63.6, 33.7, and 40.3% of the heat produced during and after the three warm-up intensities, respectively. The balance of the heat loss was assumed to be via the evaporation of sweat. On this basis, the heat loss by sweating was 14.9, 49.1, and 42.3% of the heat produced during and after the three warm-up intensities, which represented evaporation of 0.8, 3.1, and 3.0 liters of sweat, respectively. O2 consumption during exercise and heart rates 20 min postexercise, after two of the warm-up regimens, was significantly lower than that after no prior warm-up.

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Kintz, Pascal, Rudolf Brenneisen, Petra Bundeli, and Patrice Mangin. "Sweat testing for heroin and metabolites in a heroin maintenance program." Clinical Chemistry 43, no. 5 (May 1, 1997): 736–39. http://dx.doi.org/10.1093/clinchem/43.5.736.

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Abstract Recent advances in sensitive analytical techniques have enabled the analysis of drugs in unconventional biological materials such as sweat. In a study conducted during a heroin maintenance program, 14 subjects had sweat patches applied, then received intravenously two or three doses of heroin hydrochloride ranging from 80 to 1000 mg/day. The sweat patch was applied 10 min before the first dosage and removed ∼24 h later, minutes before the next dosage. Absorbent pads were stored at −20 °C in plastic tubes until analysis. The target drugs were extracted in 5 mL of acetonitrile in the presence of 100 ng each of heroin-d9, 6-acetylmorphine-d3, and morphine-d3. After agitation for 30 min, the acetonitrile solution was divided into two portions: 2 mL for heroin testing and the remainder for testing for the other compounds. After evaporation, the residue of the first portion was reconstituted in 35 μL of acetonitrile; the second was derivatized by silylation with 40 μL of N,O-bis(trimethylsilyl)trifluoroacetamide containing 10 mL/L trimethylchlorosilane. Drugs were analyzed by GC-MS in electron impact mode. Concentrations (nanograms per patch) ranged from 2.1 to 96.3 for heroin, 0 to 24.6 for 6-acetylmorphine, and 0 to 11.2 morphine. Except in one case, heroin was the major drug present in sweat, followed by 6-acetylmorphine and morphine. We observed no correlation between the doses of heroin administered and the concentrations of heroin measured in sweat.

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Anitaş, Özgül. "The sweat fatty acid content of Holstein and Jersey cows in Summer." Pakistan Journal of Agricultural Sciences 59, no. 06 (November 1, 2022): 901–6. http://dx.doi.org/10.21162/pakjas/22.1534.

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Sweat is important in thermoregulation, helping to dissipate heat in the body by evaporation in hot conditions in dairy cows. The purpose of this study was to evaluate the variation of sweat fatty acid compositions in summer conditions in Jersey and Holstein dairy cattle for their potential thermoregulatory roles in animal health protection. Temperature, relative humidity and Temperature-Humidity Index (THI) values were calculated for the intensity of stress in the indoor environment. The chemical compounds of sweat were determined by gas chromatography device and inter-breeds differences were revealed. As a result of analyzes, a total of 23 fatty acids were detected in both breeds. It was understood that there were 15 fatty acids in the Jersey breed. Palmitic acid was detected at a rate of 27.72 % in Holstein cows and 25.16 % in jersey cows that may be due to a higher rate of fatty acid release from muscle tissue, so that it may be less resistant than the jersey breed in heat stress conditions. It can be said that palmitic acid can be an indicator for heat stress conditions. ∑SFA and ∑PUFA contents of the sweat of Holstein cows were lower than those of Jersey breeds while ∑MUFA content was higher than those of Jersey breeds. The high expulsion of ∑SFA and ∑PUFA in the sweat of the Jersey cows can provide the function of delaying the body's dehydration by forming a hydrolipid film on the skin surface in hot conditions

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Guan, Hongye, Tianyan Zhong, Haoxuan He, Tianming Zhao, Lili Xing, Yan Zhang, and Xinyu Xue. "A self-powered wearable sweat-evaporation-biosensing analyzer for building sports big data." Nano Energy 59 (May 2019): 754–61. http://dx.doi.org/10.1016/j.nanoen.2019.03.026.

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Kakitsuba, Naoshi. "Dynamic changes in sweat rates and evaporation rates through clothing during hot exposure." Journal of Thermal Biology 29, no. 7-8 (October 2004): 739–42. http://dx.doi.org/10.1016/j.jtherbio.2004.08.048.

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Alber-Wallerstr�m, B., and I. Holm�r. "Efficiency of sweat evaporation in unacclimatized man working in a hot humid environment." European Journal of Applied Physiology and Occupational Physiology 54, no. 5 (November 1985): 480–87. http://dx.doi.org/10.1007/bf00422956.

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34

Budd, GM, JR Brotherhood, AL Hendrie, SE Jeffery, FA Beasley, BP Costin, W. Zhien, MM Baker, NP Cheney, and MP Dawson. "Project Aquarius 7. Physiological and Subjective Responses of Men Suppressing Wildland Fires." International Journal of Wildland Fire 7, no. 2 (1997): 133. http://dx.doi.org/10.1071/wf9970133.

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The responses of four crews of 7-8 men were measured while they attempted to suppress well-developed experimental bushfires of intensities commonly faced by hand-tool crews, and also while they built fireline in the same way without fire, during three summers in dry eucalypt forests of SW and SE Australia. Average values were sweat rate 1,144 g h-1, heart rate (HR) 152 beats min-1, and rectal temperature (Tre) 38.2° C. Changes in the average temperatures of clothed and unclothed skin were negligible, indicating efficient evaporation of sweat. Firefighters considered the work 'somewhat hard', and felt 'just too warm' and 'wet' with sweat. By contrast, the responses of the scientific observers, doing less strenuous work in the same environment, were minimal: sweat rate 292 g h-1, HR 80 beats min-1, and Tre 37.6°C. Firefighters' responses were mainly due to exertion rather than fire, confirming an identical finding from measurements of their energy expenditure and thermal environment. Differences between attacks with and without fire were small in both groups (HR 8-9 beats min-1, Tre 0.1-0.2 degrees C) except for sweat rate (firefighters 401 g h-1, observers 181 g h-1), and were usually present before the attacks began. All responses were highly consistent over the four crews, three summers, and two regions. The above findings show that the firefighters worked within their capacity and paced themselves to sustain their own preferred equilibrium levels of strain. They also demonstrate the effectiveness of the firefighters' clothing and work practices.

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35

Faradilla, Arnes. "PENGARUH JENIS BAHAN PAKAIAN TERHADAP RESPON FISIOLOGI DAN PSIKOLOGI MANUSIA PADA SAAT BEROLAHRAGA DI LINGKUNGAN PANAS." J@ti Undip : Jurnal Teknik Industri 12, no. 3 (September 22, 2017): 181. http://dx.doi.org/10.14710/jati.12.3.181-188.

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Abstrak Penyebaran panas (thermal) dan kelembaban/ uap air melalui pakaian melibatkan proses penguapan, kondensasi, penyerapan, dan desorpsi. Pakaian bertindak sebagai penghalang yang menghambat penguapan sehingga pakaian yang memiliki kemampuan penguapan yang baik akan menguntungkan pada saat melakukan berolahraga. Tujuan dari penelitian ini adalah mengetahui respon fisiologi dan psikologi manusia pada saat berolahraga di lingkungan panas.Penelitian dilakukan pada 4 orang laki-laki dengan memakai dua jenis pakaian dengan bahan berbeda, yakni: katun dan poliester pada kondisi temperatur di lingkungan 30°C. Mereka berolahraga menggunakan treadmill dengan kecepatan 7 km/ jam untuk setiap jenis pakaian selama 30 menit, dimana setiap 10 menit melakukan treadmill kemudian istirahat selama 5 menit. Setelah itu, dilakukan proses recovery selama 30 menit sebanyak dua kali.Hasil penelitian menunjukan bahwa kemampuan absorbsi keringat pada saat exercise pada bahan pakaian katun lebih tinggi dibandingkan bahan poliester, sedangkan kemampuan evaporasi keringat ketika proses recovery, bahan pakaian poliester lebih baik dibandingkan katun, sehingga pada saat ini berolahraga, bahan poliester cenderung lebih kering dibandingkan bahan pakaian katun. Untuk respon psikologi, pada saat responden berolahraga menggunakan bahan pakaian katun, mereka merasakan badan lebih terasa panas, basah dan sangat berkeringat. Abstract Thermal and humidity can be transfered using evaporation, condensation and absorption process. Clothing as a mediator to evaporation process. There are many kinds of clothing which can help to evaporating the thermal, especially while exercise. The purpose of this research is to know the Psychological and Physiological responds of human while exercise in hot environment.This research is conducted to four man who using two different kinds of clothing, which are cotton and polyester. The condition of hot environment is 30°C. They are doing exercise using treadmill with speed 7 km/hour for every kind of cloth during 30 minutes; where every 10 minutes is exercise then 5 minutes is break. After that, recovery process is 30 minutes in two times.The result of this research is shown that the ability of sweat absorbtion when exercise using cotton is higher than polyester, and the ability of sweat evaporation when recovery using polyester is more drying rather than using cotton. Polyester is better than cotton when it was used in exercise, because of polyester is easier to be dried. In Psychologycal respond, the respondences said that when using cotton while exercise, they feel the body is more warm, wet and vigorously sweating. Keywords: Pshycological, Phisiological, Cotton, Polyester, Treadmill

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36

Simmonds, L. P., and E. J. Burke. "Application of a coupled microwave, energy and water transfer model to relate passive microwave emission from bare soils to near-surface water content and evaporation." Hydrology and Earth System Sciences 3, no. 1 (March 31, 1999): 31–38. http://dx.doi.org/10.5194/hess-3-31-1999.

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Abstract. The paper examines the stability of the relation between microwave emission from the soil and the average near-surface water content in the case of relatively smooth, bare soils, and then considers the extent to which microwave radiometry can be used to estimate the effective surface resistance to vapour transfer, which is also related to the near-surface water status. The analysis is based on the use of a model (MICRO-SWEAT) which couples a microwave radiative transfer model with a SVAT scheme that describes the exchanges of water vapour, energy and sensible heat at the land surface. Verification of MICRO-SWEAT showed good agreement (about 3K RMSE) between predicted L band (1.4 GHz) brightness temperature over soils with contrasting texture during a multi-day drydown, and those measured using a truck-mounted radiometer. There was good agreement between the measured and predicted relations between the average water content of the upper 2 cm of the soil profile and the brightness temperature normalised with respect to the radiometric surface temperature. Some of the scatter in this relationship was attributable to diurnal variation in the magnitude of near-surface gradients in temperature and water content, and could be accounted for by using the physically-based simulation model. The influence of soil texture on this relationship was well-simulated using MICRO-SWEAT. The paper concludes by demonstrating how MICRO-SWEAT can be used to establish a relationship between the normalised brightness temperature and the surface resistance for use in the prediction of evaporation using the Penman-Montheith equation.

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Nett, Jeniel E., Tarika Patel, Chad Johnson, and John Kernien. "2889. Skin Niche Conditions Trigger C. auris to Form Robust Biofilms That Resist Desiccation." Open Forum Infectious Diseases 6, Supplement_2 (October 2019): S78. http://dx.doi.org/10.1093/ofid/ofz359.167.

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Abstract Background Emerging pathogen Candida auris, the first fungus to be labeled as a public health threat, causes nosocomial outbreaks of invasive candidiasis with mortality as high as 60%. Little is known about the pathogenesis of this species that has newly arisen in the last 10 years. It is unclear why this species readily colonizes the skin and transmits efficiently in healthcare settings. We considered the possibility that C. auris may proliferate in conditions of the skin niche. Methods We analyzed the growth of C. auris (B11203) in synthetic sweat media that was designed to mimic human axillary sweat. We included C. albicans SC5314 as a comparison. To simulate sweat evaporation, we examined fungal growth in sweat media that had been concentrated up to 2.5-fold. We utilized OD600 readings to quantify planktonic and biofilm growth. Biofilm architecture was assessed by scanning electron microscopy. To determine the resilience of biofilms, biofilm viability was assessed by viable burden following desiccation. Results In the various concentrations of sweat media, C. auris formed biofilms that were 3.5- to 5-fold greater that those observed for C. albicans (A). In contrast, C. auris biofilms formed in RPMI-MOPS were approximately half the density of the C. albicans biofilms. During planktonic growth in synthetic sweat media, C. auris and C. albicans replicated similarly, including in media that had been concentrated 2.5-fold. This suggests that the various media conditions differently trigger biofilm formation for the two species. The C. auris biofilm formed in sweat media was approximately 100-fold more resistant to 1 week of desiccation (B). Conclusion Skin niche conditions trigger C. auris to form resilient biofilms that resist desiccation. We propose that this unique characteristic may account for the propensity of this species to colonize the skin and for its capacity to persist on the surface of contaminated medical devices. Disclosures All Authors: No reported Disclosures.

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Heising, M., and J. Werner. "Influences of overall thermal balance on local inputs for drive of evaporation in men." Journal of Applied Physiology 62, no. 3 (March 1, 1987): 926–31. http://dx.doi.org/10.1152/jappl.1987.62.3.926.

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Three kinds of experiments were carried out in a climatic chamber: experiments with warm load on the whole body at 36 degrees C (4 subjects); experiments at 36 degrees C with reduction of thermal load (28 degrees C) on the left leg (right leg at 36 degrees C) (8 subjects); and experiments at 36 degrees C with antisymmetric thermal load on the legs of 44 degrees C (right leg) and 28 degrees C (left leg), which resulted in additional thermal loads of +/- 30 W/leg (8 subjects). The additional thermal loads, which were applied via two climatic boxes, produced measurable effects on sweat rate when applied to one leg only. In comparison to the experiment 1, experiment 2 brought about a significant reduction of local evaporation on the left leg. With antisymmetric thermal loads on both legs (experiment 3), which did not influence the overall thermal balance, there was no significant influence on local evaporation, although significant changes of local temperatures were measured. It is suggested that the well-known regulatory models, declaring local, mean skin, and core temperatures as local evaporation drive should be supplemented with an important additional feature: local control of evaporation by local skin temperature may be blocked by an overall thermal balance.

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Cho, Myung-Yeon, Ik-Soo Kim, Seok-hun Kim, Chulhwan Park, Nam-Young Kim, Sang-Wook Kim, Sunghoon Kim, and Jong-Min Oh. "Unique Noncontact Monitoring of Human Respiration and Sweat Evaporation Using a CsPb2Br5-Based Sensor." ACS Applied Materials & Interfaces 13, no. 4 (January 26, 2021): 5602–13. http://dx.doi.org/10.1021/acsami.0c21097.

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Lee, CheongCheon, Seulki Kang, Jiwon Seo, and Jonghwi Lee. "Temperature-Responsive On–Off Control over Water Evaporation Achieved via Sweat-Gland-Mimetic Composites." ACS Applied Materials & Interfaces 13, no. 3 (January 11, 2021): 4442–49. http://dx.doi.org/10.1021/acsami.0c16292.

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García, Zoilo Andrés Correa, Rómulo Campos Gaona, and Hernando Flórez Díaz. "Design and testing of a sweat meter for the cutaneous evaporation determination in cattle." Journal of Animal Behaviour and Biometeorology 8, no. 3 (2020): 223–28. http://dx.doi.org/10.31893/jabb.20029.

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42

Amin, Rafiul, and Rose T. Faghih. "Physiological characterization of electrodermal activity enables scalable near real-time autonomic nervous system activation inference." PLOS Computational Biology 18, no. 7 (July 28, 2022): e1010275. http://dx.doi.org/10.1371/journal.pcbi.1010275.

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Electrodermal activities (EDA) are any electrical phxenomena observed on the skin. Skin conductance (SC), a measure of EDA, shows fluctuations due to autonomic nervous system (ANS) activation induced sweat secretion. Since it can capture psychophysiological information, there is a significant rise in the research work for tracking mental and physiological health with EDA. However, the current state-of-the-art lacks a physiologically motivated approach for real-time inference of ANS activation from EDA. Therefore, firstly, we propose a comprehensive model for the SC dynamics. The proposed model is a 3D state-space representation of the direct secretion of sweat via pore opening and diffusion followed by corresponding evaporation and reabsorption. As the input to the model, we consider a sparse signal representing the ANS activation that causes the sweat glands to produce sweat. Secondly, we derive a scalable fixed-interval smoother-based sparse recovery approach utilizing the proposed comprehensive model to infer the ANS activation enabling edge computation. We incorporate a generalized-cross-validation to tune the sparsity level. Finally, we propose an Expectation-Maximization based deconvolution approach for learning the model parameters during the ANS activation inference. For evaluation, we utilize a dataset with 26 participants, and the results show that our comprehensive state-space model can successfully describe the SC variations with high scalability, showing the feasibility of real-time applications. Results validate that our physiology-motivated state-space model can comprehensively explain the EDA and outperforms all previous approaches. Our findings introduce a whole new perspective and have a broader impact on the standard practices of EDA analysis.

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Nascimento, Mara Regina Bueno de Mattos, Enéias Aurélio Dias, Thaisa Reis dos Santos, Gustavo Ferreira Ayres, Carolina Cardoso Nagib Nascimento, and Marcelo Emílio Beletti. "Effects of age on histological parameters of the sweat glands of Nellore cattle." Revista Ceres 62, no. 2 (April 2015): 129–32. http://dx.doi.org/10.1590/0034-737x201562020001.

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The sweat glands are important in thermoregulation of cattle in a warm environment as they help dissipate heat through evaporation. Studies on gland histology are important to define its secretion potential and the capacity of perspiration and heat removal. The objective of this study was to determine, by histomorphometry, glandular epithelium height, the depth of the gland, length of the glandular portion and number of glands per cm2 of the sweat glands of the three age groups of Nellore cattle. Thirty females were used in this study. They were equally divided into calves, heifers and cows. Histological sections were obtained and analyzed by digital images in Trinocular BX40 Olympus microscope coupled to an Oly - 200 camera, connected to a computer. The images were obtained with microscope with 2x, 4x, 10x and 40x magnification objectives. The measurements were performed using HL Image 97 program. The height of glandular epithelium, depth of the glands, length and density of the glandular portion per cm2 , were all analyzed. The calves showed greater height of the glandular epithelium than heifers (P = 0.0024), and cows (P = 0.0191). The depth of the gland was not influenced by age. Cows had higher length of secretory portion than heifers (P = 0.0379) and calves (P = 0.0077). Heifers had a greater number of sweat glands per cm2 of skin than cows (P = 0.023). In cattle, the height of glandular epithelium and the density decreases as animals get older. On the other hand, the length of the secretor portion increases but with no changes in the depth of the sweat glands

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Zhang, Xueping, Jiachen Yang, Ramadan Borayek, Hao Qu, Dilip Krishna Nandakumar, Qian Zhang, Jun Ding, and Swee Ching Tan. "Super-hygroscopic film for wearables with dual functions of expediting sweat evaporation and energy harvesting." Nano Energy 75 (September 2020): 104873. http://dx.doi.org/10.1016/j.nanoen.2020.104873.

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45

Monty-Bromer, Chelsea, Zachary Cheney, Shelby Daniels, Dunia Jaffal, Ruth Kurak, Orlando Lopez, Gabe Manzo, Mary Pat Nicodemus, and Ronald Otterstetter. "(Invited) Carbon Nanotube-Based Fabric Sensor for Selective Sodium Detection in Sweat." ECS Meeting Abstracts MA2022-01, no. 8 (July 7, 2022): 674. http://dx.doi.org/10.1149/ma2022-018674mtgabs.

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Despite the recent advancements in sensor detection of biomarkers in sweat, there is no sensor capable of long-term detection in constricted or load-bearing applications where other flexible plastic sensors might cause discomfort. In this work, a carbon nanotube-based fabric sensor capable of real-time detection of sodium in human sweat is presented. The sensor consists of an electrospun nylon-6 base functionalized with multi-walled carbon nanotubes for enhanced conductivity and p-tert-calix[4]arene for enhanced sodium selectivity. Monitoring sweat is a compelling choice to gain insight into a person’s hydration at a molecular level, as sweat is rich in physiological and metabolic information that can be obtained non-invasively. Body surface sweat is approximately 99% water but also contains over 40 other compounds, most notably the presence of extracellular ions: sodium and chloride. Sodium has been shown to have a notable correlation to body fluid balance and is lost in ample quantities during exercise, making it a promising candidate for the detection of dehydration (i.e., hypernatremia) and overhydration (i.e., hyponatremia). Other compounds commonly found in surface sweat include intracellular ions, metabolites, hormones, small proteins, and peptides. This rich composition and its correspondence to blood chemistry can be the key to accessing the body’s biomolecular (health) state through non-invasive monitoring and diagnostics. When monitoring biomarkers in sweat, the sampling step has the greatest impact on accuracy. Traditional methods for monitoring sweat sodium concentration involve collecting a sweat sample and performing chemical analysis in two separate steps. Typical sweat collection procedures include whole body washdown, sweat collection patches, arm bags, and Macroducts® which require some combination of tedious procedures, trained professionals, and large equipment for analysis. These methods are often limited by insufficient sample volumes, non-negligible sample evaporation, possible analyte degradation between sampling and analysis all of which strongly impacts the reliability and sensitivity of the measurement. To circumvent the problems caused by separating sampling and analysis, sweat sampling can also be completed using wearable sensors. Through in-situ sampling and analysis, wearable sweat sensors can perform the necessary real-time measurements with freshly generated sweat rather than a mixture of new and old sweat. Functional absorbent materials (e.g., paper, nonwoven, cellulosic, or hydrogels) are typically introduced between the skin and the sensing component; although as shown in this work, they can also be introduced as sensing components during sampling. The advantages of functional absorbent sensing materials are their low cost, multiple functions, real-time and continuous sensing, and most importantly the enhanced breathability of sweat glands. As such, these wearable sensors avoid the issue of altering the sweat composition underneath because they remove the old sweat accumulation as new sweat wicks into the material and washes away old sweat. This also allows physiological monitoring for longer periods of time than traditional epidermal microfluidic devices. Additionally, functional absorbent materials can also be integrated into fabrics with inherent moisture wicking properties to bring sweat to a sensing area. This work presents the characterization and on-body testing of a previously developed functional absorbent material sensor made of a multi-walled carbon nanotube (MWCNT) functionalized nylon-6 nanocomposite. The wearable-fabric sensor works by measuring resistance of the nanocomposite material as sodium binds to the sensor fabric. The functionalization of the nanocomposite material was verified by FTIR; while XRD spectra show that the electrospun nylon-6 is made of -form crystals and the resulting nanocomposite is intercalated/exfoliated with an increase in crystalline size. The optimized MWCNT/nylon-6 nanocomposite sensor has a MWCNT loading close to the percolation threshold at approximately 1-2 wt%. Experimental results demonstrated that the sensor is selective to sodium in sweat at a sensitivity of 10 mM sodium. When worn on the body (attached to human skin), the sensor is capable of real-time monitoring of sodium concentration in sweat in the physiologically relevant range of 10-110 mM with up to 95% accuracy. Additionally, the obtained signal can be sent out via Bluetooth so that changes in hydration status can be detected in real-time. Overall, this carbon nanotube-based fabric sensor can be integrated into “smarter” clothing to read an array of biomarkers in sweat. This could lead to better understanding of health and disease processes (e.g., analysis of common diabetic neurological complications, diagnosis of cystic fibrosis (CF), sweat monitoring for advanced prosthetic limb applications and bedridden patients, and athlete performance tracking) resulting in better treatments and health outcomes for all patients. Figure 1

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Budd, GM, JR Brotherhood, AL Hendrie, SE Jeffery, FA Beasley, BP Costin, W. Zhien, MM Baker, NP Cheney, and MP Dawson. "Project Aquarius 6. Heat Load From Exertion, Weather, and Fire in Men Suppressing Wildland Fires." International Journal of Wildland Fire 7, no. 2 (1997): 119. http://dx.doi.org/10.1071/wf9970119.

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Firefighters' thermal environment was continuously measured while they attempted to suppress well-developed experimental bushfires of intensities commonly faced by hand-tool crews, and also while they built fireline in the same way without fire, during three summers in Australian eucalypt forests. They worked far enough from the flames to avoid painful intensities of radiant heat (>2 kW m-2) on bare skin and usually experienced 1.6 kW m-2 - little more than the intensity of sunlight Fire had negligible effects on average air temperature, humidity, or wired speed. Exertion accounted for 71% of the total heat load, fire and weather for the remainder. Evaporation was effectively the sole means of heat dissipation, and predicted sweat loss exceeded one litre per hour. Indices of heat stress usually exceeded occupational limits proposed for heat-acclimatized men, although little additional strain resulted. We conclude that firefighters should be fit and acclimatized, wear light and loose clothing that imposes minimal resistance to evaporation, and drink at least 1 litre of water per hour.

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Kolibu, Hesky Stevy, and Verna Albert Suoth. "Kajian Eksperimen Pengaruh Lingkungan Panas Terhadap Suhu Kulit Manusia Menggunakan Fast Response Temperature Probe PS-2135 dan Temperature Array PS-2157." Jurnal MIPA 8, no. 2 (July 22, 2019): 67. http://dx.doi.org/10.35799/jmuo.8.2.2019.24252.

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Fisika merupakan ilmu alam yang saling berkaitan dengan ilmu lainnya. Salah satu keterkaitannya mempelajari sistem adaptasi tubuh manusia terhadap perubahan suhu. Suhu kulit adalah faktor mendasar dalam pertukaran panas antara tubuh dan lingkungannya. Tingkat suhu kulit secara langsung mempengaruhi transfer energi oleh konveksi dan radiasi dan juga memengaruhi kehilangan panas dari penguapan keringat. Dalam studi eksperimental ini, nilai perubahan suhu kulit dikumpulkan menggunakan Fast Response Temperature Probe PS-2135 dan Temperature Array PS-2157. Tujuan dari studi ini adalah untuk menyelidiki efek dari lingkungan panas pada respon fisiologis suhu kulit tubuhPhysics is a natural science that is interrelated with other sciences. One connection is studying the human body's adaptation system to temperature changes. Skin temperature is a fundamental factor in heat exchanges between the body and its environment. The level of skin temperature directly affects the energy transfer by convection and radiation and also influences heat losses from sweat evaporation. In this experimental study, the skin temperature changes values are collected using Fast Response Temperature Probe PS-2135 and Temperature Array PS-2157. The purpose of this study was to investigate the effects of warm environmental on physiological responses of body skin temperaturePhysics is a natural science that is interrelated with other sciences. One connection is studying the human body's adaptation system to temperature changes. Skin temperature is a fundamental factor in heat exchanges between the body and its environment. The level of skin temperature directly affects the energy transfer by convection and radiation and also influences heat losses from sweat evaporation. In this experimental study, the skin temperature changes values are collected using Fast Response Temperature Probe PS-2135 and Temperature Array PS-2157. The purpose of this study was to investigate the effects of warm environmental on physiological responses of body skin temperature

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48

McLellan, Tom M., and Yukitoshi Aoyagi. "Heat Strain in Protective Clothing Following Hot-Wet or Hot-Dry Heat Acclimation." Canadian Journal of Applied Physiology 21, no. 2 (April 1, 1996): 90–108. http://dx.doi.org/10.1139/h96-009.

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The purpose of the present study was to compare the heat strain while wearing nuclear, biological, and chemical (NBC) protective clothing following a hot-wet (HW) or hot-dry (HD) heat acclimation protocol. Twenty-two males were assigned to groups HW (n = 7), HD (n = 8), or control (C, n = 7). Subjects were evaluated during continuous treadmill walking while wearing lightweight combat clothing and during intermittent exercise while wearing the NBC protective clothing. While wearing Combat clothing, greater decreases in rectal temperature (Tre), mean skin temperature [Formula: see text], and heart rate were observed for both acclimation groups. For the NBC clothing trials, lower Tre, [Formula: see text], and heart rates were observed only for group HW. The time required for Tre to increase 1.0 °C and 1.5 °C was significantly delayed for groups HW and HD. Sweat evaporation increased for HW, whereas no change was found for HD. The most significant changes in Tre, [Formula: see text], and heart rate while wearing the NBC protective clothing occur following heat acclimation that involves wearing the clothing during exercise. Key words: rectal temperature, mean skin temperature, heart rate, sweat rate

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49

Moran, D., Y. Epstein, A. Laor, A. Vitalis, and Y. Shapiro. "Predicting heart rate response to various metabolic rates, environments, and clothing." Journal of Applied Physiology 78, no. 1 (January 1, 1995): 318–22. http://dx.doi.org/10.1152/jappl.1995.78.1.318.

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A mathematical model that describes heart rate (HR) responses to different combinations of metabolic levels, climatic conditions, and clothing ensembles was developed. The database that served to construct the model consisted of 48 variations representing a wide range of environmental conditions, clothing ensembles, and metabolic rates. The model, which correlates highly with the observed values (r = 0.88, P < 0.0001), is based on physiological and environmental parameters: HR = 57.1 + 0.6HRi + [0.07M - 19.06 – 0.011(Emax - Ereq)] log t, where HRi is initial HR in beats per minute (at rest before the exposure), t is the time of exposure in minutes, M is the metabolic rate in watts, Ereq is the required sweat evaporation for thermal equilibrium in watts, and Emax is the maximal evaporative capacity of the environment in watts. The model's validity was tested by using two independent databases representing wide ranges of conditions; the correlation between measured and predicted values was found to be highly significant (r = 0.83, P < 0.001 and r = 0.77, P < 0.001, respectively). In summary, the present study suggests a valid predictive model for HR that overcomes some of the difficulties observed in other models.

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50

Yum, Seoung-Mok, In-Keun Baek, Dongpyo Hong, Juhan Kim, Kyunghoon Jung, Seontae Kim, Kihoon Eom, et al. "Fingerprint ridges allow primates to regulate grip." Proceedings of the National Academy of Sciences 117, no. 50 (November 30, 2020): 31665–73. http://dx.doi.org/10.1073/pnas.2001055117.

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Fingerprints are unique to primates and koalas but what advantages do these features of our hands and feet provide us compared with the smooth pads of carnivorans, e.g., feline or ursine species? It has been argued that the epidermal ridges on finger pads decrease friction when in contact with smooth surfaces, promote interlocking with rough surfaces, channel excess water, prevent blistering, and enhance tactile sensitivity. Here, we found that they were at the origin of a moisture-regulating mechanism, which ensures an optimal hydration of the keratin layer of the skin for maximizing the friction and reducing the probability of catastrophic slip due to the hydrodynamic formation of a fluid layer. When in contact with impermeable surfaces, the occlusion of the sweat from the pores in the ridges promotes plasticization of the skin, dramatically increasing friction. Occlusion and external moisture could cause an excess of water that would defeat the natural hydration balance. However, we have demonstrated using femtosecond laser-based polarization-tunable terahertz wave spectroscopic imaging and infrared optical coherence tomography that the moisture regulation may be explained by a combination of a microfluidic capillary evaporation mechanism and a sweat pore blocking mechanism. This results in maintaining an optimal amount of moisture in the furrows that maximizes the friction irrespective of whether a finger pad is initially wet or dry. Thus, abundant low-flow sweat glands and epidermal furrows have provided primates with the evolutionary advantage in dry and wet conditions of manipulative and locomotive abilities not available to other animals.

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