Transient Thermal Response of Skin Tissue

2008 ◽  
Author(s):  
Muge Pirtini Cetingul ◽  
Cila Herman
Keyword(s):  
Temperature Distribution ◽  
Surface Temperature ◽  
Thermal Imaging ◽  
Imaging Techniques ◽  
Thermal Response ◽  
Sensitivity Study ◽  
Subsurface Structures ◽  
Surface Temperature Distribution ◽  
Transient Thermal ◽  
Transient Thermal Response

The increased availability of thermal imaging cameras has led to a growing interest in the application of infrared imaging techniques to the detection and identification of subsurface structures. These imaging techniques are based on the following principle: when a surface is heated or cooled, variations in the thermal properties of a structure located underneath the surface result in identifiable temperature contours on it. These contours are characteristic of the structure’s shape, depth, and its thermal properties. We study the use of the transient thermal response of skin layers to determine to which extent the surface temperature distribution reflects the properties of subsurface structures, such as lesions. A numerical model using the finite element method is described to obtain this response and key results are reported in the paper. A sensitivity study is conducted first to better understand the thermal response of the system and the role of various system and model parameters. We explore the extent to which we are able to draw conclusions regarding the size, depth and nature of subsurface structures and accuracy of these conclusions based on the surface temperature response alone. This work validates the idea of examining the transient thermal response and using thermal imaging as a solution for lesion identification. A sensitivity study of surface temperature distribution to variations of thermophysical properties, blood perfusion rate, and thicknesses of skin layers is performed. It is observed that variations in these parameters have little impact on the surface temperature distribution. The work reported in the paper is a portion of a comprehensive research effort involving experiments on a phantom model as well as measurements on patients. Future work will focus on comparing the results of our 2D numerical modeling efforts with the experimental results using a skin tissue-mimicking phantom. Knowledge gained from the modeling and experimental efforts will be utilized in characterizing lesions in patient studies. The focus of this paper is the computational sensitivity analysis.

The use of thermal imaging measurements in dairy cow herds

2018 ◽  
Vol 14 (1) ◽  
pp. 55-69
Author(s):  
Przemysław Racewicz ◽  
Jakub Sobek ◽  
Michał Majewski ◽  
Jolanta Różańska-Zawieja
Keyword(s):  
Temperature Distribution ◽  
Surface Temperature ◽  
Environmental Conditions ◽  
Thermal Imaging ◽  
Blood Perfusion ◽  
Individual Characteristics ◽  
The Body ◽  
Technical Parameters ◽  
Surface Temperature Distribution ◽  
Imaging Parameters

temperature distribution on the surface of an animal’s body. The surface temperature values obtained in IRT depend on the quantitative impact of the conditions of the surrounding environment and the thermoregulatory response of the animal. Besides the blood perfusion volume, the skin temperature depends on the metabolic rate of tissues, the type and colour of the hair coat, and the thickness of the adipose tissue. In a healthy organism, the temperature distribution between individual parts of the body shows a high degree of symmetry. Analysis of the surface temperature distribution of a given area of the body of an animal which is in homeostasis with the external environment provides a great deal of valuable information. By comparing the same parts of the body, we can easily identify hot spots, and the additional knowledge gained during more extensive veterinary diagnostics increases the chance of establishing the cause of this condition. The reliability of IRT depends on the technical parameters of the cameras, environmental conditions, the operator’s experience, the animal’s individual characteristics, and the testing methodology. As many factors can affect the surface temperature distribution of an animal’s body, and thus the result of the thermographic measurement, the effect of any stimuli interfering with the measurements should be minimized during thermal imaging. Additionally, in order to reduce the risk of misinterpretation of the image, normalization protocols for imaging parameters, i.e. standards ensuring reliable results, should be applied. The main limitation in the implementation of these standards in thermography of livestock animals is that it is not possible to compare thermograms made under different environmental conditions. Research has been carried out to assess the suitability of thermal imaging cameras in diagnosing inflammatory changes in the skin of cattle. The technique was found to have great potential in predicting local inflammation (hoof, udder or skin disease). Normalization protocols must be developed for imaging parameters, i.e. standards that will ensure reliable results in a variety of environmental conditions.

Damage Detection in Composite Beam Using the Temperature Distribution

2006 ◽  
Author(s):  
Ezequiel Medici ◽  
Andres Cecchini ◽  
David Serrano ◽  
Frederick Just
Keyword(s):  
Temperature Distribution ◽  
Damage Detection ◽  
Mathematical Formulation ◽  
Thermal Response ◽  
Sandwich Composite ◽  
Approximation Technique ◽  
Beam Model ◽  
Transient Thermal ◽  
Transient Thermal Response ◽  
Damage Type

Marine, aerospace, ground and civil structures can receive unexpected loading that may compromise integrity during their life span. Therefore, improvement in detecting damage can save revenue and lives depending upon the application. The prognostic capability is usually a function of the examiner's experience, background and data collection during the evaluation. Nondestructive evaluation (NDE) methods are varied and specific to a given type of system (material, damage type, loading and environmental scenarios). As a result, one method of damage detection alone cannot examine all possible conditions and may even give false readings. This work examined the transient thermal response technique to assess damage in a sandwich composite structure. The mathematical formulation of the problem is presented. Then, a numerical approximation technique is used to solve the governing equations. The thermal distribution on the surface of a beam model is analyzed when damage is introduced. Then, an experimental setup with an Infrared (IR) thermography camera was assembled in order to provide the necessary information about the surface temperature distribution over the beam. Several damages scenarios will be tested by the technique with the purpose of determining the limitations of the method. The obtained experimental data was used to validate the numerical model. Finally, the feasibility of this feature to use in damage detection is discussed.

Transient Thermal Response of Skin Tissue

2008 ◽  
Author(s):  
Muge Pirtini Cetingul ◽  
Cila Herman
Keyword(s):  
Thermal Properties ◽  
Computer Technology ◽  
Infrared Imaging ◽  
Imaging Techniques ◽  
Thermal Response ◽  
Skin Tissue ◽  
Infrared Sensor ◽  
Transient Thermal ◽  
Transient Thermal Response ◽  
Structure Result

Recent improvements in infrared sensor and computer technology led to the resurgence of the infrared imaging in medicine. The technique has many advantages such as being noninvasive and relatively less expensive than MRI or ultrasound. These imaging techniques are based on the following principle: when a surface is heated or cooled, variations in the thermal properties of a structure result in identifiable temperature contours on it. These contours are characteristic of the structure’s shape, depth, and its thermal properties.

Evaluation of Package Defects by Thermal Imaging Techniques

2002 ◽  
Author(s):  
Yongmei Liu ◽  
Rajen Dias
Keyword(s):  
Infrared Thermography ◽  
Thermal Imaging ◽  
High Speed ◽  
Imaging Techniques ◽  
Thermal Response ◽  
Analysis Tool ◽  
Nondestructive Analysis ◽  
Ir Camera ◽  
External Heating

Abstract Study presented here has shown that Infrared thermography has the potential to be a nondestructive analysis tool for evaluating package sublayer defects. Thermal imaging is achieved by applying pulsed external heating to the package surface and monitoring the surface thermal response as a function of time with a high-speed IR camera. Since the thermal response of the surface is affected by the defects such as voids and delamination below the package surface, the technique can be used to assist package defects detection and analysis.

Influence of Phonon Dispersion on Transient Thermal Response of Silicon-on-Insulator Transistors Under Self-Heating Conditions

2006 ◽  
Vol 129 (7) ◽  
pp. 790-797 ◽  
Author(s):  
Rodrigo A. Escobar ◽  
Cristina H. Amon
Keyword(s):  
Computational Models ◽  
Phonon Dispersion ◽  
Thermal Response ◽  
Domain Size ◽  
Phonon Transport ◽  
Silicon On Insulator ◽  
Nonlinear Relation ◽  
Temperature Levels ◽  
Transient Thermal ◽  
Transient Thermal Response

Lattice Boltzmann method (LBM) simulations of phonon transport are performed in one-dimensional (1D) and 2D computational models of a silicon-on-insulator transistor, in order to investigate its transient thermal response under Joule heating conditions, which cause a nonequilibrium region of high temperature known as a hotspot. Predictions from Fourier diffusion are compared to those from a gray LBM based on the Debye assumption, and from a dispersion LBM which incorporates nonlinear dispersion for all phonon branches, including explicit treatment of optical phonons without simplifying assumptions. The simulations cover the effects of hotspot size and heat pulse duration, considering a frequency-dependent heat source term. Results indicate that, for both models, a transition from a Fourier diffusion regime to a ballistic phonon transport regime occurs as the hotspot size is decreased to tens of nanometers. The transition is characterized by the appearance of boundary effects, as well as by the propagation of thermal energy in the form of multiple, superimposed phonon waves. Additionally, hotspot peak temperature levels predicted by the dispersion LBM are found to be higher than those from Fourier diffusion predictions, displaying a nonlinear relation to hotspot size, for a given, fixed, domain size.

Transient thermal response in ultrasonic additive manufacturing of aluminum 3003

2011 ◽  
Vol 17 (5) ◽  
pp. 369-379 ◽  
Author(s):  
David Schick ◽  
Sudarsanam Suresh Babu ◽  
Daniel R. Foster ◽  
Marcelo Dapino ◽  
Matt Short ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Thermal Response ◽  
Ultrasonic Additive Manufacturing ◽  
Transient Thermal ◽  
Transient Thermal Response
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