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Hidradenitis suppurativa (HS) is a chronic, inflammatory, and recurrent skin disease. Surgical excision of wounds appears to be the only curative treatment for the prevention of recurrence of moderate to severe stages. Magnetic resonance imaging (MRI) is a standard reference examination for the detection of HS peri-anal inflammatory fistula. In this case study, the use of real-time medical infrared thermography, in combination with MRI as appropriate imaging, is proposed. The aim is to assist surgeons in the pre- and peri-surgical management of severe perianal hidradenitis suppurativa with the intent to ensure that all diseased lesions were removed during surgery and therefore to limit recurrence. The results show that medical infrared thermography (MIT), coupled with MRI, could be highly effective strategy to address thermally distinguished health tissues and inflammatory sites during excision, as characterised by differential increases in temperature. Medical infrared thermography could be used to check the total excision of inflammatory lesions as a noninvasive method that is not painful, not radiant, and is easily transportable during surgery. Ultimately, this method could be complementary with MRI in providing clinicians with objective data on the status of tissues below the perianal skin surface in the pre- and per-operating management of severe hidradenitis suppurativa.

In the present paper, an application of infrared thermography to inverse heat conduction problems is presented. The study involves the identification of conductive losses at the jaws of a tensile testing machine, which must be assessed in situ, because of variable fastening conditions of the specimen, inducing variable thermal resistances at the jaws. For this purpose, a photo-thermal technique has been developed to identify all the heat exchanges of the sample. An optical excitation, based on a halogen lamp projector, illuminates the specimen in situ on the tensile machine, while the radiative flux excitation is measured using a photodiode. The conductive fluxes are identified, transient and steady, then the equivalent exchange coefficients at the jaws. For this purpose, a direct numerical model by finite differences and an inverse procedure allow to estimate these exchange coefficients. The resolution of the inverse problem is based on the optimization by the conjugate gradient method, of a least square criterion between the temperatures measured by infrared thermography and the temperatures calculated from the direct model.

The pressure ulcers are injuries caused by a constant pressure and without slackening, which damage skin and the subcutaneous flesh, because of the lack of mobility and blood circulation. The injur...

Thermal resistances between liners and engine blocks are nondestructively studied by photothermal infrared thermography. Under controlled sinusoidal light irradiation, the thermal response of the sample is measured by means of an infrared camera. A numerical lock-in procedure yields amplitude and absolute phase maps of the thermal field periodic component. Then, apart from classical qualitative detection of air layers, a quantitative characterization of thermal resistance becomes available. An analytical modeling, associated with an inverse procedure using the Gauss–Newton parameter estimation method, allows to identify the thermal resistance on academic samples representative of the liner-engine block interface. Simply joined cast iron and aluminum plates present thermal resistances about 2 × 10 −3 K m 2 W −1 . The implementation of a numerical modeling allows to study two-dimensional defects. When the samples are pressed on their periphery, thus straightened, contact resistances ranging from 2 × 10 −4 to 7 × 10 −4 K m 2 W −1 have been measured. Then, the method is applied to liner-engine block interfaces where the thermal resistances fall to about 2 × 10 −5 K m 2 W −1 , matching the values obtained when a cast iron plate is locally pressed against an aluminum plate.

Thermographic lock-in investigation of thermal interaction between a thermal probe used in scanning thermal microscopy and a thin composite sample is used for estimating the relative fraction of heat flux transferred to the sample by conduction through the air and by direct local contact. The latter is determined by vector subtraction of out-of-contact data from in-contact data, for different modulation frequencies. It represents only 8% of the total modulated heat flux dissipated by the probe, and is frequency-independent. The heat transfer by air conduction varies between 23% and 6% for f = 0.2...40 Hz with a broad equivalent heat source radius of r 0.2 mm.

This paper presents a measurement method of the thermal dissipation in metallic samples submitted to a plastic strain. Its interest is to extend the field of experimental investigation of the irreversible plastic transformations. The method is applied to the quantification of the thermal dissipation effects associated to the impact of a ball on a thin metallic sample. The final aim of the study consists in proposing a complementary method for controlling and monitoring the shot-peening process. The temperature rise at the rear face after the impact of the ball at the front-face is measured by infrared thermography. Then, the dissipated heat is deduced from the registered thermograms, via a parameter estimation procedure, by a comparison with a specially developed heat diffusion model. The first results presented here show that a preliminary shot-peening of the samples induces a reduction in the energy dissipated during the impact. Then, a specific study has been carried out in order to point out the diminution of the dissipated heat with the number of previous shots.

Mechanical stresses, applied or residual, are identified by means of photothermal infra- red thermography. Stresses are detected via their influence on thermophysical properties and more particularly on the thermal conductivity tensor. Because this influence remains weak, a sufficiently accurate identification procedure is needed as well as a significant enhancement of the signal-to-noise ratio, by means of a focal plane array camera.

Using complementary thermal wave methods, the irradiation damaged region of zirconium carbide (ZrC) is characterized by quantifiably profiling the thermophysical property degradation. The ZrC sample was irradiated by a 2.6 MeV proton beam at 600 °C to a dose of 1.75 displacements per atom. Spatial scanning techniques including scanning thermal microscopy (SThM), lock-in infrared thermography (lock-in IRT), and photothermal radiometry (PTR) were used to directly map the in-depth profile of thermal conductivity on a cross section of the ZrC sample. The advantages and limitations of each system are discussed and compared, finding consistent results from all techniques. SThM provides the best resolution finding a very uniform thermal conductivity envelope in the damaged region measuring ∼52 ± 2 μm deep. Frequency-based scanning PTR provides quantification of the thermal parameters of the sample using the SThM measured profile to provide validation of a heating model. Measured irradiated and virgin thermal conductivities are found to be 11.9 ± 0.5 W m−1 K−1 and 26.7 ±1 W m−1 K−1, respectively. A thermal resistance evidenced in the frequency spectra of the PTR results was calculated to be (1.58 ± 0.1) × 10−6 m2 K W−1. The measured thermal conductivity values compare well with the thermal conductivity extracted from the SThM calibrated signal and the spatially scanned PTR. Combined spatial and frequency scanning techniques are shown to provide a valuable, complementary combination for thermal property characterization of proton-irradiated ZrC. Such methodology could be useful for other studies of ion-irradiated materials.

International audience; This paper aimed to study the feasibility of application of infrared thermography to detect osteoarthritis of the knee and to compare the distribution of skin temperature between participants with osteoarthritis and those without pathology. All tests were conducted at LACM (Laboratory of Mechanical Stresses Analysis) and the gymnasium of the University of Reims Champagne Ardennes. IR thermography was performed using an IR camera. Ten participants with knee osteoarthritis and 12 reference healthy participants without OA participated in this study. Questionnaires were also used. The participants with osteoarthritis of the knee were selected on clinical examination and a series of radiographs. The level of pain was recorded by using a simple verbal scale (0-4). Infrared thermography reveals relevant disease by highlighting asymmetrical behavior in thermal color maps of both knees. Moreover, a linear evolution of skin temperature in the knee area versus time has been found whatever the participant group is in the first stage following a given effort. Results clearly show that the temperature can be regarded as a key parameter for evaluating pain. Thermal images of the knee were taken with an infrared camera. The study shows that with the advantage of being noninvasive and easily repeatable, IRT appears to be a useful tool to detect quantifiable patterns of surface temperatures and predict the singular thermal behavior of this pathology. It also seems that this non-intrusive technique enables to detect the early clinical manifestations of knee OA.

The aim of the present study is to characterize the variations of thermal resistances between liners and engine blocks of cars; a non-destructive evaluation is proposed: photothermal infrared thermography. The thermal response of the sample submitted to a modulated optical stimulation is measured by means of an infrared camera. Then, a numerical lock-in procedure yields both amplitude and absolute phase maps of the thermal field periodic component. On the one hand, an analytical modelling, associated with an inverse procedure using the Gauss-Newton parameter estimation method, allows the identification of the thermal resistance on academic samples, representative of the liner-engine block interface. On the other hand, the implementation of a numerical modelling allows studying two-dimensional defects at the cast iron-aluminium interface. Finally, the method is applied to liner-engine block interfaces. The measured thermal resistances match the values obtained when a cast iron plate and an aluminium plate are pressed together.

Integral transforms (Laplace, Fourier, Hankel) are widely used to solve the heat diffusion equation. Moreover, it often appears relevant to realize the estimation of thermophysical properties in the transformed space. Here, an analytical model has been developed, leading to a well-posed inverse problem of parameter identification. Two black coatings, a thin black paint layer and an amorphous carbon film, were studied by photothermal infrared thermography. A Hankel transform has been applied on both thermal model and data and the estimation of thermal diffusivity has been achieved in the Hankel space. The inverse problem is formulated as a non-linear least square problem and a Gauss-Newton algorithm is used for the parameter identification.