The Numerical Thermal Simulation of the Human Body When Undergoing Exercise or Nonionizing Electromagnetic Irradiation

1976 ◽  
Vol 98 (2) ◽  
pp. 284-291 ◽  
Author(s):  
A. F. Emery ◽  
R. E. Short ◽  
A. W. Guy ◽  
K. K. Kraning ◽  
J. C. Lin
Keyword(s):  
Human Body ◽  
Numerical Procedure ◽  
Thermal Response ◽  
Analytical Models ◽  
Entire Body ◽  
Local Skin ◽  
Temperature Changes ◽  
Major Mode ◽  
Average Skin ◽  
Skin Temperatures

The human body was modeled by a finite difference numerical procedure to determine the effect of simulating the sweating rate by different analytical models. Six different models were used in which the hypothalamus, muscle, average skin, and local skin temperatures were used as the controlling parameters for the rate of local sweating. These different models were tested by comparing their predictions of local temperatures for an exercising man with measured values. The computer program was then used to compute the thermal response of a man subjected to microwave irradiation of the entire body and the head only. Transient head and body temperatures and sweating rates were computed and compared with the temperature changes due to an equivalent exercise level. Significant differences in the results found by using the different sweat models point out the need for further work in determining accurate analytical descriptions of this major mode of body heat loss.

scholarly journals On the use of facial and neck cooling to improve indoor occupant thermal comfort in warm conditions

2021 ◽  
Author(s):  
Bin Yang ◽  
Tze-Huan Lei ◽  
Faming Wang ◽  
Pengfei Yang
Keyword(s):  
Thermal Comfort ◽  
Thermal Sensation ◽  
Average Energy ◽  
Entire Body ◽  
Cooling Mode ◽  
Local Skin ◽  
Scale Unit ◽  
Cooling Fans ◽  
Skin Temperatures ◽  
Neck Cooling

Face and neck cooling has been found effective to improve thermal comfort during exercise in the heat despite the surface area of human face and neck regions accounts for only 5.5% of the entire body. Presently, very limited work in the literature has been reported on face and neck cooling to improve indoor thermal comfort. In this work, two energy-efficient wearable face and neck cooling fans were used to enhance occupant thermal comfort in two warm indoor conditions (30 & 32 °C). Local skin temperatures and perceptual responses while using those two wearable cooling fans were examined and compared. Results showed that both cooling fans could largely reduce local skin temperatures at the forehead, face and neck regions up to 2.1 °C. Local thermal sensation votes at the face and neck were decreased by 0.82-1.21 scale unit at two studied temperatures. Overall TSVs dropped by 1.03-1.14 and 1.34-1.66 scale unit at 30 and 32 °C temperatures, respectively. Both cooling fans could extend the acceptable HVAC temperature setpoint to 32.0 °C, resulting in an average energy saving of 45.7% as compared to the baseline HVAC setpoint of 24.5 °C. Further, the free-control cooling mode is recommended to occupants for further improving thermal comfort while using those two types of wearable cooling fans indoors. Lastly, it is concluded that those two wearable cooling fans could greatly improve thermal comfort and save HVAC energy despite some issues on dry eyes and dry lips associated with those wearable cooling fans were noted.

scholarly journals On the Use of Wearable Face and Neck Cooling Fans to Improve Occupant Thermal Comfort in Warm Indoor Environments

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8077
Author(s):  
Bin Yang ◽  
Tze-Huan Lei ◽  
Pengfei Yang ◽  
Kaixuan Liu ◽  
Faming Wang
Keyword(s):  
Thermal Comfort ◽  
Energy Efficient ◽  
Thermal Sensation ◽  
Entire Body ◽  
Cooling Mode ◽  
Local Skin ◽  
Cooling Fans ◽  
The Face ◽  
Skin Temperatures ◽  
Neck Cooling

Face and neck cooling has been found effective in improving thermal comfort during exercise in the heat despite the fact that the surface area of human face and neck regions accounts for only 5.5% of the entire body. Presently very little documented research has been conducted to investigate cooling the face and neck only to improve indoor thermal comfort. In this study, two highly energy efficient wearable face and neck cooling fans were used to improve occupant thermal comfort in two warm indoor conditions (30 and 32 °C). Local skin temperatures and perceptual responses while using the two wearable cooling fans were examined and compared. Results showed that both cooling fans could significantly reduce local skin temperatures at the forehead, face and neck regions by up to 2.1 °C. Local thermal sensation votes at the face and neck were decreased by 0.82–1.21 scale unit at the two studied temperatures. Overall TSVs decreased by 1.03–1.14 and 1.34–1.66 scale units at 30 and 32 °C temperatures, respectively. Both cooling fans could raise the acceptable HVAC temperature setpoint to 32.0 °C, resulting in a 45.7% energy saving over the baseline HVAC setpoint of 24.5 °C. Furthermore, occupants are advised to use the free-control cooling mode when using those two types of wearable cooling fans to improve thermal comfort. Finally, despite some issues on dry eyes and dry lips associated with those wearable cooling fans, it is concluded that those two highly energy-efficient wearable cooling fans could greatly improve thermal comfort and save HVAC energy.

scholarly journals A validation study on the thermal simulation of the human body-clothing-environment system through wear trials

2021 ◽  
Vol 16 ◽  
pp. 155892502110413
Author(s):  
Muhammad Awais ◽  
Sybille Krzywinski ◽  
Bianca-Michaela Wölfling ◽  
Edith Classen
Keyword(s):  
Human Body ◽  
Validation Study ◽  
Thermal Simulation ◽  
3D Analysis ◽  
Local Skin ◽  
Air Gaps ◽  
Deformation Properties ◽  
Clothing Fit ◽  
Core Body ◽  
Skin Temperatures

The following analysis deals with the validation study for the already published thermal simulation of the human body-clothing-environment system through wear trials. Three test persons and a clothing system were selected for this study. The simulation process chain includes 3D scanning, clothing fit considering the deformation properties of fabrics, 3D analysis of air gaps between skin and clothing, and thermophysiological analysis of the human body taking into account different metabolic rates. Moreover, subjective wear trials were performed in a climatic chamber to validate the simulation results. The results show good validation for the core body and mean skin temperature, however, discrepancies were observed on comparing the local skin temperatures. The presented simulation approach offers a holistic solution for product development in the areas of sportswear, workwear, outdoor, and protective clothing.

Characterization of Thermal and Acoustic Profiles of Potential Underwater Pipeline Leaks

2014 ◽  
Author(s):  
Shane Siebenaler ◽  
Eric Tervo ◽  
Mohan Kulkarni ◽  
Sandeep Patni ◽  
Glenn Gesoff
Keyword(s):  
Near Field ◽  
Thermal Response ◽  
Third Party ◽  
Analytical Models ◽  
Distributed Temperature Sensing ◽  
Offshore Installations ◽  
Underwater Pipeline ◽  
Optic Systems ◽  
Measurement Mechanism ◽  
Gas Leaks

Reliable detection of small potential leaks is a topic of significant interest for remote offshore pipelines. Potential leak cases of interest are pinhole leaks out of the bottom of the pipe due to corrosion, weld or seam cracks, or damage due to third-party contact. There are several emerging technologies that may have the potential to provide a means of detecting such leaks over long segments of underwater pipe. These technologies include distributed acoustic and distributed temperature sensing. A key element of evaluating the applicability of these systems is to characterize the behavior of leaks. It is critically important to understand how leaks behave when employing a technology that has only been previously used for other conditions. A joint-industry program was initiated to evaluate the thermal and acoustic behavior of hypothetical underwater leaks. The environments studied range from shallow, Arctic applications to deep offshore installations. Analytical models were assessed to predict the jetting behavior of simulated leaks and their near-field thermal response. This analysis was performed for both liquid and gas media. These models were validated by means of laboratory experiments. Acoustic characteristics of hypothetical liquid and gas leaks were determined by means of testing with hydrophones. This information can be leveraged by a number of technologies as the data are independent of the measurement mechanism. While the motivation of this work is to evaluate distributed fiber-optic systems, the data on leak characteristics may also provide indications on applicability of other techniques for detecting potential underwater leaks. The data from this project will allow the industry to improve the understanding of potential leaks from underwater pipelines and, hence, lay the foundation for determining appropriate detection systems.

scholarly journals High-Performance Workwear for Coal Miners in Northern China: Design and Performance Evaluation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ying Ke ◽  
Qing Zheng ◽  
Faming Wang ◽  
Min Wang ◽  
Yi Wang
Keyword(s):  
Performance Evaluation ◽  
Thermal Comfort ◽  
High Performance ◽  
Northern China ◽  
Coal Miners ◽  
Climate Chamber ◽  
Local Skin ◽  
Worker Performance ◽  
And Performance ◽  
Skin Temperatures

Abstract The design of workwear has significant effects on worker performance. However, the current workwear for coal miners in Northern China is poor in fitness and thermal comfort. In this study, new workwear (NEW) for coal miners was developed with the design features providing better cold protection and movement comfort performance, as compared with a commonly worn workwear (CON). To evaluate the effectiveness of NEW, we conducted human trials which were performed using simulated work movements (i.e., sitting, shoveling, squatting, and crawling) in a climate chamber (10°C, 75% RH). Physiological measurements and perceptual responses were obtained. The results demonstrated that the local skin temperatures at chest, scapula, thigh, and calf; mean skin temperatures,; and thermal comfort in NEW were significantly higher than those in CON. NEW also exerted an improvement in enhancing movement comfort. We conclude that NEW could meet well with the cold protective and mobility requirements.

Linear thermoelasticity

2020 ◽  
pp. 257-285
Author(s):  
Lallit Anand ◽  
Sanjay Govindjee
Keyword(s):  
Linear Theory ◽  
Mechanical Response ◽  
Thermal Response ◽  
Engineering Applications ◽  
Temperature Changes ◽  
Weakly Coupled ◽  
Linear Thermoelasticity ◽  
Basic Equations ◽  
Fully Coupled ◽  
Coupled Theory

This chapter presents a theory for the coupled thermal and mechanical response of solids under circumstances in which the deformations are small and elastic, and the temperature changes from a reference temperature are small --- a framework known as the theory of linear thermoelasticity. The basic equations of the fully-coupled linear theory of anisotropic thermoelasticity are derived. These equations are then specialized for the case of isotropic materials. Finally, as a further specialization a weakly-coupled theory in which the temperature affects the mechanical response, but the deformation does not affect the thermal response, are discussed; this is a specialization which is of importance for many engineering applications, a few of which are illustrated in the examples.

scholarly journals Prediction of physiological exertion in hot environments using the JOS-2 thermoregulation model

2019 ◽  
Vol 111 ◽  
pp. 02058
Author(s):  
Akihisa Nomoto ◽  
Yoshito Takahashi ◽  
Yoshiichi Ozeki ◽  
Masayuki Ogata ◽  
Shin-ichi Tanabe
Keyword(s):  
Metabolic Rate ◽  
Human Body ◽  
Heat Stroke ◽  
High Accuracy ◽  
Outdoor Environment ◽  
Heat Island ◽  
Rate Measurement ◽  
Mean Skin Temperature ◽  
Local Skin ◽  
Hot Environments

In recent years, the outdoor summer environment in Japan has become progressively warmer due to the severity of the heat island phenomenon. The danger of heat stroke and thermal comfort outdoors in summer are regarded as problems. In order to evaluate these problems, it is important to evaluate physiological exertion in the human body. The purpose of this research is to demonstrate the possibility of predicting physiological exertion in the human body with high accuracy in an outdoor environment during summer using the JOS-2 thermoregulation model developed by our research group. First, the Japanese metabolic rate in summer and autumn was measured for various activities, including sitting, standing, and walking. As a result, we found that the metabolic rate during sitting and standing was lower by about 10% in summer than in autumn. Next, using the obtained metabolic rate measurement as an input to the model, the experiment in an outdoor environment during summer was reproduced using JOS-2. The accuracy of the predicted mean skin temperature and local skin wettedness in an outdoor environment during summer was improved by choosing the appropriate input to the model.

A STUDY OF THE EFFECT OF COLD ON JOINT TEMPERATURE AND MOBILITY

1951 ◽  
Vol 29 (5) ◽  
pp. 255-262 ◽  
Author(s):  
John Hunter ◽  
M. G. Whillans
Keyword(s):  
Knee Joint ◽  
Test Object ◽  
Joint Stiffness ◽  
Ambient Temperatures ◽  
Significant Fall ◽  
Average Skin ◽  
Skin Temperatures ◽  
Rectal Muscle

Exposure to zero and subzero ambient temperatures results in a significant fall in joint temperature, where the knee joint of the cat was used as test object. The fall in rectal, muscle, and “average” skin temperatures for similar exposures is considerably less. Low joint temperature is associated with increased joint stiffness.

Physiological reactions of Caucasian and Bantu males in acute exposure to cold

1964 ◽  
Vol 19 (4) ◽  
pp. 583-592 ◽  
Author(s):  
C. H. Wyndham ◽  
J. S. Ward ◽  
N. B. Strydom ◽  
J. F. Morrison ◽  
C. G. Williams ◽  
...  
Keyword(s):  
Body Temperature ◽  
Ethnic Differences ◽  
Metabolic Response ◽  
Climatic Chamber ◽  
Air Temperatures ◽  
Metabolic Reactions ◽  
The Difference ◽  
Physiological Reactions ◽  
Average Skin ◽  
Skin Temperatures

Eleven men per sample of Caucasian and Bantu males were exposed for 2 hr in a climatic chamber at various air temperatures ranging from 5 to 27 C, and a wind velocity of 80–100 ft/min. When expressed per square meter surface area the metabolism of the Bantu was greater in the range above 18 C and below 6 C. Average skin temperatures were similar for both groups, but between 27 and 17 C the toe and finger temperatures of the Caucasians were significantly higher than that of the Bantu—the difference at 27 C being 5 C for the fingers and 3.6 C for the toes. Rectal temperatures of both groups were similar between 27 and 17 C. With the rectal temperatures at 27 C air temperature as the criterion, it was found that as the air temperatures decreased below the 27–17 C range the rectal temperatures of the Bantu fell linearly, while the rectal temperatures of the Caucasians rose steadily. There is no doubt that in certain ranges of air temperatures there are significant differences between the cold reactions of Caucasians and the Bantu. cold adaptation; ethnic differences in response to cold; metabolic and body temperature reactions to cold; metabolic response to body temperature; metabolic reactions of ethnic groups Submitted on July 15, 1963

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