Multi-Compartment Cooling∕Warming Garment for Human Thermal Dynamic Research and Medical Applications

2008 ◽  
Vol 2 (2) ◽  
Author(s):  
Victor S. Koscheyev ◽  
Gloria R. Leon ◽  
Joo-Young Lee ◽  
Joe M. Warpeha ◽  
Daniel A. Saltzman
Keyword(s):  
Heat Transfer ◽  
The Body ◽  
Heat Extraction ◽  
Thermal Environments ◽  
Body Regions ◽  
Cooling Garment ◽  
Conductive Properties ◽  
Occupational Settings ◽  
Thermal Stimuli ◽  
Simultaneous Heat

Human thermoregulatory research is fraught with multifaceted physiological issues. A notable quandary is the fact that the human body has several different types of tissues, each with unique heat transfer/conductive properties. The primary goal of our research is to determine how to effectively and appropriately regulate human thermal physiology in the context of medical, occupational, and sporting fields. Of paramount importance is quantifying heat extraction/insertion from various body regions under different heat surplus/deficit situations imposed by environmental conditions and/or metabolic fluctuations, and understanding the associated mechanisms and their relationships. Our laboratory has conducted research involving the simulation of contradictory thermal regimes on the body surface to observe the dynamic process of simultaneous heat insertion and extraction. To achieve this, we have designed a tubing cooling/warming garment through which water circulates and controller (patent #7,089,995) that can provide the desired thermal stimuli in uniform/non-uniform and symmetrical/non-symmetrical patterns. We believe this methodology of divided surfaces for the application of concurrent cooling/warming regimes affords the greatest opportunity to quantify the maximum zonal capabilities for heat transfer. This paradigm allows for the regulation of heat flow in dynamic non-uniform conditions and is particularly suited for the comfort/support of a range of clinical populations (e.g., surgical, multiple sclerosis, burns/trauma, hyper/hypothermia). It is also applicable for the design of protective clothing for personnel in occupational settings (e.g., military, firefighting, space flyers), and for sporting apparel (i.e., a cooling garment/hood/blanket). Our laboratory has used the physiologically designed cooling/warming garment to evaluate individual thermoregulatory profiles elicited by conditions representative of extreme terrestrial and space thermal environments.

scholarly journals A Computational Study on the Role of Parameters for Identification of Thyroid Nodules by Infrared Images (and Comparison with Real Data)

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4459
Author(s):  
José R. González ◽  
Charbel Damião ◽  
Maira Moran ◽  
Cristina A. Pantaleão ◽  
Rubens A. Cruz ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thyroid Nodules ◽  
Numerical Study ◽  
Computational Study ◽  
Internal Heat ◽  
Heat Transfer Process ◽  
The Body ◽  
Physical Parameters ◽  
Infrared Sensors ◽  
Wide Range

According to experts and medical literature, healthy thyroids and thyroids containing benign nodules tend to be less inflamed and less active than those with malignant nodules. It seems to be a consensus that malignant nodules have more blood veins and more blood circulation. This may be related to the maintenance of the nodule’s heat at a higher level compared with neighboring tissues. If the internal heat modifies the skin radiation, then it could be detected by infrared sensors. The goal of this work is the investigation of the factors that allow this detection, and the possible relation with any pattern referent to nodule malignancy. We aim to consider a wide range of factors, so a great number of numerical simulations of the heat transfer in the region under analysis, based on the Finite Element method, are performed to study the influence of each nodule and patient characteristics on the infrared sensor acquisition. To do so, the protocol for infrared thyroid examination used in our university’s hospital is simulated in the numerical study. This protocol presents two phases. In the first one, the body under observation is in steady state. In the second one, it is submitted to thermal stress (transient state). Both are simulated in order to verify if it is possible (by infrared sensors) to identify different behavior referent to malignant nodules. Moreover, when the simulation indicates possible important aspects, patients with and without similar characteristics are examined to confirm such influences. The results show that the tissues between skin and thyroid, as well as the nodule size, have an influence on superficial temperatures. Other thermal parameters of thyroid nodules show little influence on surface infrared emissions, for instance, those related to the vascularization of the nodule. All details of the physical parameters used in the simulations, characteristics of the real nodules and thermal examinations are publicly available, allowing these simulations to be compared with other types of heat transfer solutions and infrared examination protocols. Among the main contributions of this work, we highlight the simulation of the possible range of parameters, and definition of the simulation approach for mapping the used infrared protocol, promoting the investigation of a possible relation between the heat transfer process and the data obtained by infrared acquisitions.

scholarly journals Numerical Investigation on the Influence of Surface Flow Direction on the Heat Transfer Characteristics in a Granite Single Fracture

2021 ◽  
Vol 11 (2) ◽  
pp. 751
Author(s):  
Xuefeng Gao ◽  
Yanjun Zhang ◽  
Zhongjun Hu ◽  
Yibin Huang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Flow Rate ◽  
Flow Direction ◽  
Heat Extraction ◽  
Geothermal System ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Heat Transfer Capacity

As fluid passes through the fracture of an enhanced geothermal system, the flow direction exhibits distinct angular relationships with the geometric profile of the rough fracture. This will inevitably affect the heat transfer characteristics in the fracture. Therefore, we established a hydro-thermal coupling model to study the influence of the fluid flow direction on the heat transfer characteristics of granite single fractures and the accuracy of the numerical model was verified by experiments. Results demonstrate a strong correlation between the distribution of the local heat transfer coefficient and the fracture morphology. A change in the flow direction is likely to alter the transfer coefficient value and does not affect the distribution characteristics along the flow path. Increasing injection flow rate has an enhanced effect. Although the heat transfer capacity in the fractured increases with the flow rate, a sharp decline in the heat extraction rate and the total heat transfer coefficient is also observed. Furthermore, the model with the smooth fracture surface in the flow direction exhibits a higher heat transfer capacity compared to that of the fracture model with varying roughness. This is attributed to the presence of fluid deflection and dominant channels.

scholarly journals Inter-body coupling in electro-quasistatic human body communication: theory and analysis of security and interference properties

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mayukh Nath ◽  
Shovan Maity ◽  
Shitij Avlani ◽  
Scott Weigand ◽  
Shreyas Sen
Keyword(s):  
Channel Capacity ◽  
Body Surface ◽  
Human Body ◽  
Communication Theory ◽  
The Body ◽  
Body Area ◽  
Theoretical Understanding ◽  
Communication Modality ◽  
Conductive Properties ◽  
Human Body Communication

AbstractRadiative communication using electromagnetic fields is the backbone of today’s wirelessly connected world, which implies that the physical signals are available for malicious interceptors to snoop within a 5–10 m distance, also increasing interference and reducing channel capacity. Recently, Electro-quasistatic Human Body Communication (EQS-HBC) was demonstrated which utilizes the human body’s conductive properties to communicate without radiating the signals outside the body. Previous experiments showed that an attack with an antenna was unsuccessful at a distance more than 1 cm from the body surface and 15 cm from an EQS-HBC device. However, since this is a new communication modality, it calls for an investigation of new attack modalities—that can potentially exploit the physics utilized in EQS-HBC to break the system. In this study, we present a novel attack method for EQS-HBC devices, using the body of the attacker itself as a coupling surface and capacitive inter-body coupling between the user and the attacker. We develop theoretical understanding backed by experimental results for inter-body coupling, as a function of distance between the subjects. We utilize this newly developed understanding to design EQS-HBC transmitters that minimizes the attack distance through inter-body coupling, as well as the interference among multiple EQS-HBC users due to inter-body coupling. This understanding will allow us to develop more secure and robust EQS-HBC based body area networks in the future.

Heat transfer depends on the region of the body and the thickness of the skin

Burns ◽  
2021 ◽  
Author(s):  
Judith C.J. Holzer-Geissler ◽  
Petra Kotzbeck ◽  
Lars-Peter Kamolz
Keyword(s):  
Heat Transfer ◽  
The Body

Influence on Skin Burns by Water Absorbed Station Wear and Underwear in Firefighter Clothing

2013 ◽  
Vol 796 ◽  
pp. 623-629
Author(s):  
Kaoru Wakatsuki ◽  
Norimasa Morii ◽  
Yoshio Ogawa ◽  
Hajime Tsuji
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Evaluation Method ◽  
The Body ◽  
Electric Heater ◽  
Copper Sensor ◽  
Wet Condition ◽  
Transfer Index ◽  
Wear Condition

During firefighting, within firefighter clothing, underwear and station wear gets heavily wet due to firefighting water and moisture from the body. Water has higher thermal conductivity relative to air and it has been expected that heavily wet condition within the firefighter clothing makes faster skin burns. The objective of this study is how the wet condition within a firefighter clothing makes faster heat transfer from feeling pain and to being 2nd degree of skin burns relative to the dry condition in case of routine firefighting operation in a building (up to 20 kW/m2). Aramid station wear and cotton underwear, generally used by a Japanese firefighter, have been selected and cut 0.15 m x 0.15 m to attach an ISO 9151 copper sensor. A cone shape electric heater, which produces 12 kW/m2 to 20 kW/m2, was used to heat the fabrics. Scenario of fabrics are that (1) wet station wear and dry underwear, (2) wet station and wet underwear, (3) dry station wear and wet underwear, and (4) dry station wear and dry underwear. Evaluation method was by a heat transfer index (HTI) by ISO 9151. The time to rise temperature of 12 and 24 °C (HTI12 and HTI24), and heat transfer rate (dT/dt) were investigated for above four scenarios. The result shows that there was significant impact by condition of station wear, but little impact by underwear. In heat transfer rate (dT/dt) analysis, for the situation of feeling pain to the 2nd degree of skin burns (from HTI12 to HTI24), heat transfer rate was about 50% higher relative to the dry station wear condition. This result indicates that it is possible to be 2nd degree of skin burns easily as soon as a firefighter feels the pain, if he/she wears wet station wear.

Seasonal changes in the body surface temperature of Hanwoo (Bos taurus coreanae) steers

2014 ◽  
Vol 54 (9) ◽  
pp. 1476 ◽  
Author(s):  
N. Y. Kim ◽  
S. J. Kim ◽  
J. H. Park ◽  
M. R. Oh ◽  
S. Y. Jang ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Ambient Temperature ◽  
Body Surface ◽  
Seasonal Changes ◽  
Bos Taurus ◽  
The Body ◽  
Body Regions ◽  
Extreme Cold ◽  
Body Surface Temperature ◽  
Average Body

The present study aimed to gather basic information on measuring body surface temperature (BST) of cattle by using infrared thermography (IRT) and find out whether BST measurement is a useful method to detect thermal balance of livestock. Twenty-seven Hanwoo steers were examined in a field trial. The BST of five body regions (eye, nose, horn, ear, rear) was measured five times daily, with three replicates, during 3 days each season. Body surface temperature of cattle is directly affected by ambient temperature and humidity, and showed different ranges for each region. The BSTs of nose, horns and ears were significantly (P < 0.05) lower than those of eyes and rear area. Rear-area BST was significantly lower than eye-area BST when the ambient temperature was low (P < 0.05). Eye BST (EBST) was highest (P < 0.05) and the least variable of all BSTs measured. Therefore, the eye area of cattle was the most thermostable part of the body. There were significant (P < 0.05) differences among seasonal EBSTs of steers. The EBST range was highest in the summer (37.9–42.2°C), followed by autumn (34.3–37.4°C), spring (33.8–36.5°C) and winter (29.8–32.6°C). During extreme cold, EBST showed a large standard deviation. During conditions of extreme heat, EBST was above the average body temperature of cattle. The results of the present study indicated that BST well reflects the thermal circumstances surrounding animals and may be used as one of the effective tools for precision cattle farming.

Predicting heat extraction due to boiling in the cooling channels during the pressure die casting process

2000 ◽  
Vol 214 (3) ◽  
pp. 465-482 ◽  
Author(s):  
L D Clark ◽  
I Rosindale ◽  
K Davey ◽  
S Hinduja ◽  
P J Dooling
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Die Casting ◽  
Casting Process ◽  
Nucleate Boiling ◽  
Heat Extraction ◽  
Film Boiling ◽  
Cooling Channels ◽  
Die Casting Process ◽  
Pressure Die Casting

The effect of boiling on the rate of heat extraction by cooling channels employed in pressure die casting dies is investigated. The cooling effect of the channels is simulated using a model that accounts for subcooled nucleate boiling and transitional film boiling as well as forced convection. The boiling model provides a continuous relationship between the rate of heat transfer and temperature, and can be applied to surfaces where forced convection, subcooled nucleate boiling and transitional film boiling are taking place in close proximity. The effects of physical parameters such as flow velocity, degree of subcooling, system pressure and bulk temperature are taken into account. Experimental results are obtained using a rig that simulates the pressure die casting process. The results are compared with the model predictions and are found to show good agreement. Instrumented field tests, on an industrial die casting machine, are also reported. These tests show the beneficial effects of boiling heat transfer in the pressure die casting process, including a 75 per cent increase in the production rate for the test component.

Computational Study on Radiative Aerothermodynamics of a Reentry Space Vehicle

2021 ◽  
Author(s):  
Qi Li ◽  
Sijun Zhang
Keyword(s):  
Heat Transfer ◽  
Thermal Protection ◽  
Computational Study ◽  
Space Vehicle ◽  
The Body ◽  
Stagnation Region ◽  
Convective Flux ◽  
Transit Times ◽  
Key Issues ◽  
Nonequilibrium Flows

Abstract Under hypersonic flight conditions, a vehicle travelling through the atmosphere could excite the air that flows around the body to very high temperatures as the kinetic energy of the vehicle is dissipated to the gas. Depending on the flight velocity, various chemical reactions will be produced behind a shock wave for stagnation region. These reactions greatly change the properties of air and cause considerable deviation from those of a thermally and calorically perfect gas. A vehicle flying through the higher altitude of the atmosphere at high velocities may also experience thermal non-equilibrium since the lower density reduces the collision frequency and the high velocity results in smaller transit times for the air molecules. Under such extremely thermal circumstances, the heat transfer by convection and radiation around a vehicle has been one of key issues for thermal protection system (TPS). In this paper, the computational aerothermodynamics with fully coupled radiative heat transfer is developed. To validate the proposed approach, it is employed to simulate the thermal and chemical nonequilibrium flows over Stardust. The computed results on the reentry space vehicle reveal both of convective flux and radiative flux are in good agreements with other predicted results.

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