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An innovative ceramic material has been developed as a possible substitute of the traditional rock-wool as thermal insulating material. It should be used in the future inside a machine working at a temperature greater than 200 degrees C. The effect of exposition to this temperature for several hours has been evaluated to check if a degradation of the insulating properties can be measured. Experiments did not show any evidence of degradation. Nonetheless the value of the thermal conductivity measured both at high and ambient temperature was not so good as expected. At the same time, the same measurements on rock-wool (the traditional choice for insulation in this machinery) revealed to be very difficult as it is not possible to prepare samples to be tested in a laser flash. To overcome this problem in the measurement of the performance at high temperature a new experiment was prepared by heating one side of the material by means of an electric heater and by looking and comparing (at least qualitatively) the temperature increase on the other side. On the purpose, two parallelepiped samples of the two rival materials, with the same thickness have been prepared and put in contact with the electric heater plate. The temperature evolution of the side facing the ambient has been measured by means of a thermographic camera for almost one hour. The experiment shows that the traditional material owns better insulation performance than the innovative one. Attention has been paid on the properties of the innovative material that, being highly hygroscopic, can maintain a low temperature during the drying process due to the very high value of the latent heat of water when changing from liquid to gas phase.

Applications of Infrared Thermography in buildings surveys are not limited to the identification of the temperature distribution and heat losses on building envelopes. As it is well known from NDT testing in industrial applications, active IR thermographic methods such as heating-up/cooling-down or lock-in thermography improve the results in many investigations. In civil engineering these techniques have not been used widely. Mostly, thermography is used in a quasistatic manner. This paper illustrates a new approach to achieve, by the lock-in technique, an in depth view of the structure of the wall evidencing the presence of buried elements, interfaces and cracks. The idea is to take advantage of the periodic heating and cooling of earth surface due to the alternating of day and night. The corresponding thermal wave has a period equal to 24 hours that can probe the walls of buildings with a penetration depth of the order of some centimeters. The periodic temperature signal is analysed to extract amplitude and phase. It is expected that the phase image gives the indication of inhomogeneity buried in the wall structure. As a case study, the exterior surface of Palazzo Ducale in Venice is analysed and illustrated. In addition to IR images, visible electromagnetic band is considered to evaluate the strength of the solar radiation and the geometrical distortion. Indeed, the periodicity due to the Earth rotation is only approximately of 24 hours. The passing clouds or the possibility of rainy days can superimpose other heating or cooling frequencies to the main one. The Fourier analysis of the impinging radiation on the wall is performed. The facade of Palazzo Ducale is tiled with stone of two different colours and types. A final attempt to automatically classify the stone tiles in the visible and infrared images is conducted.

Thermography is one of many techniques used for nondestructive testing for which both passive and active approach could be taken. The passive approach is effective for materials and structures which are naturally at a different temperature than the environment. The active approach requires an external heating source to stimulate the materials or structures to be tested. These methods can be also applied to detect mines hidden in the ground. Passive approach is used when natural heating of soil by sun radiation is exploited. In the case of active approach it is used an external heating source for example a microwave source to provide thermal stimulation. In this paper the results of our experiments with both methods carried out in the laboratory set-up and in the outdoor measuring field are presented.

An alternative model to determine the wind influence from themographic inspections is addressed in this paper. A wind velocity dependent temperature reduction factor is developed and applied in order to estimate the target temperature in the absence of wind. The model makes use of only two unknown coefficients, which are identified for each case. Tests were conducted in laboratory using an aclimatiezed chamber developed to simulate actual conditions, as well in the field. The results of application were also compared to those obtained from other researchers, showing very good agreement.

In this work, different mosaics covered with various plaste rs (of thickness and compositions) were evaluated in lab by means of active long wave and mid wave thermography approaches, with the intention of detecting the tesserae beneath the plastered surface. Thermal images as well as thermal contrast curves between plastered surfaces and plastered mosaics were recorded. Special considerations concerning the applicability and accuracy of the used approaches for this specific application are presented. Results from the assessment are presented and discussed, indicating that images seeing through the mortar–plast er on plastered mosaic surfaces can be obta ined using active thermography approaches. Keywords: Thermography, non - destructive testing, plastered mosaics, detection 1. INTRODUCTION During their lifetime the different historic structural complexes have subjected to various conservation and restoration interventions. In a large number of cases such interventions have led to the covering of materials of great historical value and significance, as in the case of mosaics. With a view to the strict conservation regulations concerning historical sites and in particular mosaics, where sampling for destructive testing and investigation is prohibited, the development and use of Non- Destructive Testing and Evaluation (NDT&E) techniques is considered to be essential. NDT&E techniques such as infrared thermography have been widely used on a number of occasions in the cu ltural heritage protection area, and have been proved to provide substantial information rega rding the investigation and evaluation of historic materials and structures. There is a vast amount of research works in the literature concerning the application of IR thermography for the characterization of building materials [1], the inspection of historic buildings [2] and moisture monitoring and assessment in ancient buildings [3], the diagnosis of surface and near-surface defects [4] as well as subsurface defects [5], the subsurface investigation of materi als [6], the assessment of conservation interventions and materials in historic structures [7], the detection of subsurface layers [8], through various active approaches. In this work different plastered mosaic surfaces were investigated in the laboratory with the use of Cooling-down Thermography (CDT), Pulse Phase Thermography (PPT) an d Thermographic Signal Reconstruction (TSR) techniques, in order to identify their sub surfaces – reveal of mosaics.

This paper presents some difficulties encountered when evaluating information from infrared thermal inspections conducted in uncovered power substations. Procedural, technical and environmental are the main factors of influence identified. Based on field data and in laboratory tests, preliminary mathematical models are derived, which are suitable either to forecast the system behavior under specified conditions or to remove the influence such components.

The interaction of materials with the atmosphere has recently received increased attention. Although the interaction between atmosphere chemistry, weathering and pollutants deposition is complex, there is a need for measuring the surface materials lost through weathering and acid rain by art objects. In fact, data regarding material response to different conditions can be used to predict long-term trends in degradation as well as to assess deterioration process parameters. Conventional inspection techniques, such as ultrasonic measurements or X-ray radiography, can be time-consuming and/or expensive. In principle, methods to monitor artwork corrosion should have the following features: non-contact nature, fast and inexpensive operations, good sensitivity. In this paper an investigation on detection and monitoring of artwork corrosion by infrared thermography and optical techniques is carried out. In IR thermography, material loss is related to thermal contrast, which is defined as a suitable normalization of temperature differences on the specimen. Optical techniques basically rely on optical contouring, which leads to a 3D map of the surface. Experimental results obtained using simple inversion procedure for IR data are compared with optical results.

Monuments are continuously submitted to external events like water infiltration or condensation, temperature variation, soil instability, that lead to internal damage of the structure itself as well as of its surfaces. Wall paintings are then submitted to stresses that may cause cracks, internal de-lamination of the plaster or de-bonding between canvas and plaster. In the frame of the restoration of the "galerie des glaces" in the "château de Versailles", TV-Holography and IR Thermography have been used to investigate the wall paintings of the vault. The surfaces to control were either direct paintings on the plaster or paintings on canvas backed on the plaster. IR Thermography for art work and in particular for wall paintings has only recently been used. The technique allows to record transient temperature maps, when slightly heating the surface during a short time. Then, nonhomogeneities in the conductive heat transfer are related to de-bonding or de-lamination. The time parameter gives information on the depth of the defect. A calibration procedure has to be carried out to ensure reliable defect detection. Speckle interferometry is a Non Destructive Testing technique that is currently used in industry. For the wall paintings, we have used TV-Holography associated with a continuous wave laser. The technique allows, 13 metres away from the surface, to detect parts of the paintings that were vibrating due to an acoustic excitation. The control processes based on these two technologies is detailed as well as the results obtained and a comparison with manual investigation is done.

Corrosion of airport pavements is a major problem involved with materials engineering and transportation engineering. Airport pavements frequently start to deteriorate slowly primarily, gradually progressing to failure. Such failure can be expensive in terms of both money and lives, but can also be prevented. For that reason, intelligent techniques should be suggested, with the intention of examining the condition of such engineering structures. IR thermography and ground penetrating radar are two NDT (non-destructive testing) techniques that have the ability to inspect effectively substantial areas, such as airport pavements. In this work, two different airport pavements located at the International Airport of Athens, in Greece, were investigated by the use of the above two mentioned techniques. Successful detection of cracks, voids and other imperfections appearing either from the aging of the materials or due to poor workmanship was attained. Furthermore, this paper describes the problem of deteriorated airport pavements, shows the process and the apparatus used for the in situ tests, and finally presents results obtained from the investigations.

The paper contains theoretical and experimental thermal diffusivity data on anisotropic carbon and glass fiber reinforced composite laminates up to 5 mm thick. The effectiveness of the theory is evaluated by using a 3D numerical model. Both spot-mask and slit-mask techniques for determining lateral thermal diffusivity components are analyzed.

The simple approach to estimating corrosion detection limits in thick metallic samples has been proposed by taking into account 3D heat diffusion phenomena for circle-like defects. Experimental data has been obtained for both flash and long heating of steel samples with the thickness up to 10 mm.

Within the past five years, the Pest Management industry has become aware that IR thermography can aid in the detection of pest infestations and locate other conditions that are within the purview of the industry. This paper will review the applications that can be utilized by the pest management professional and discuss the advanced techniques that may be required in conjunction with thermal imaging to locate insect and other pest infestations, moisture within structures, the verification of data and the special challenges associated with the inspection process.

Infrared thermography is a non-destructive evaluation technique that can be used to identify debonded areas in FRP strengthening systems applied to concrete. This research provides a summary of IR thermography experiments that were conducted on full-scale AASHTO girders strengthened with four different FRP composite systems. Significant findings were that the thickness of the FRP system as well as the material composition strongly influences the ability to detect defects at the FRP/concrete interface. Additional experiments were conducted on small-scale specimens with implanted defects. Results from these experiments indicate that IR thermography is capable of detecting defects under multi-layer FRP composite systems; however the defect signal strength and time to maximum signal vary significantly from single-layer systems.

Laser welds in light-weight transit bus panels were studied by IR imaging. The corrugated structural panels were made from 3mm thick stainless steel. The panels were welded by a high power laser with lines of equally spaced 1” stitches. After discovering problems by visual and tapping inspections, the panels were sent to our laboratory for further investigation. The IR thermography method was chosen to study the welds because of its non-contact nature and potential for large area, high-speed inspections. We used thermophysical properties of the panels and finite element modeling to predict temperature variations of “good” and “bad” welds. Surface heating and “heat leak” methods were used to inspect each weld. The IR images clearly showed characteristic temperature signatures of “good” and “bad” welds. We also discovered a number of partial welds and questionable welds. In the follow-up destructive inspection, the welds interfaces were imaged and related to the infrared images. None or partial penetrations were found on a number of bad and partial welds. Even in the good welds, the weld stitch appeared to be discontinuous. This study helped the bus manufacturer to assess their welding process and make necessary improvement.

In this paper a technique based on microwave heating and IR thermography measurement for dielectric constant estimation is proposed. The effect of the propagating EM wave on the temperature distribution inside the sample under test is studied for short observations time. A model was derived and a suitable data reduction is accomplished. Preliminary results are presented and discussed for the pure water case.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

This paper gives a short introduction into the possibility of detecting foreign bodies in food by using IR thermography. The first results shown for combinations of cherries and chocolate and berries contaminated with leaves, stalks, pedicel and thorns could be easily evaluated manually. Therefore the differing emissivity coefficients or the different heat conductivities and/or capacities are used for differentiation. Applying pulse thermography, first heat conductivity measurements of different food materials are performed. Calculating the contrast of possible food / contaminant combinations shows the difficulty of differentiating certain materials. A possible automatic evaluation for raisins contaminated with wooden sticks and almonds blended with stones could be shown. The power of special adapted algorithms using statistical or morphological analysis is shown to distinguish the foreign bodies from the foodstuff.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Knowledge of an historic monument can be substantially improved by locating hidden structures, openings and the wall bonding beneath the plaster. When restoring buildings, the physical connection between the walls must be known in order to predict the risk areas for structural weakness. IR Thermography produces remarkable results, especially by means of the quantitative approach. The temperature pattern detected by thermography and analyzed in space and time maps the hidden structure of the wall. Thick walls exposed to the weather represent a challenge in detecting hidden structures by means of thermography. Frequently output is very poor because testing conditions are not optimized. Hence, appropriate testing requires careful analysis of the wall system before and after taking the thermograms. Otherwise, false alarms render the images useless. This paper describes a general procedure applied to see the hidden wall structure. It works in three steps: a) a mathematical simulation of the real test by a dedicated software, implementing the 3D thermal problem; b) a transient thermographic test, delivering a suitable heating flux on the surface for the proper time; c) processing test data, including a thermogram sequence and air temperature analysis. Here, are reported tests achieved on a XV-XVIIth century Palace at Cremona (Italy) and in the Westcott House in Springfield (OH).

Infrared thermography is used to reveal the establishment of Erwinia amylovora harpin-induced hypersensitive response (HR) in Nicotiana sylvestris leaves. We observed a decrease in temperature (1-2 degree(s)C) in the harpin infiltrated zone, correlated with an increase in stomatal opening, strongly suggesting that the temperature decrease is due to higher transpiration rate. IRT experiments were conducted in a laboratory environment and could be widely applied for genotype screening and monitoring drug effects.

The paper aims to illustrate the relevant use of IR thermography as a non-destructive, real-time and noncontact technique (a) to observe the physical processes of damage, fatigue and failure on metallic specimens subject to fatigue testing, 9B0 to detect the occurrence of intrinsic dissipation and (c) to evaluate the fatigue strength in a very short time. In addition, this IR thermographic technique readily describes the damage location and the mechanisms of structural failure.

This paper presents findings based on IR thermography in the spectral range of 3-5 micrometers of mine-like objects buried in gravel, where the surface is actively thermally stimulated. Enhanced detectability of buried objects, specifically land mines, is demonstrated to be possible. Priority is given to buried plastic AP mines. Results show that it seems possible to actively provoke an IR signature of near surface mine- like objects and that a time-domain method will be able to distinguish mines from other types of buried objects. Actively provoked IR signatures combined with a time-domain treatment method appear to have potential for further improvement of the localization of buried mines.

The use of finite element analysis for predicting surface temperatures in response to hidden features is presented. Examples of predicted temperatures for buried pipes using passive IR and for subsurface flaws using active IR are presented. The impact of various depths for the pipe and the flaw, as well as the size of the flaw are examined. The use of the approach to improve the likelihood of successful application of IR Thermography for problem solution is discussed. It is my purpose in this paper to acquaint those of you who are not aware of FEA's capabilities with those capabilities, and to demonstrate, in particular, two applications for it in the area of thermography. Many other applications are possible and I hope that the two cases presented will suggest some of them.

Bearing wear and the threat of downtime have plagued assembly lines for many years. Bearings on slow moving equipment, such as conveyors, are no exception to this problem. At the General Motors Fairfax Assembly Plant in Kansas City, Kansas, we are trying to find a solution to prevent these occurrences. Due to the slow moving nature of the production process, regular preventive maintenance has been the traditional method to regulate these problems. Now, with the aid of IR Thermography, we are able to find potential problems before they occur. The presentation will show visual and thermal images, before and after repairs, along with our reporting methods of any exceptions. This paper will touch on a few of our slow moving equipment finds.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The paper aims to illustrate three advantages of IR thermography as a nondestructive, noncontact and real time technique, (a) to observe the progressive damage processes and mechanisms of leather failure, and (b) to detect the occurrence of intrinsic dissipation localization. The parameter, investigated in this paper, is the heat generation due to intrinsic dissipation caused by inelasticity and/or inelasticity of leather. It readily describes the damage location and the failure evolution of leather for sport foot-wear.

For large scale chicken and turkey raising operations, automated 'candling' of eggs for monitoring embryonic development is effective and efficient. Candling is accomplished by the transmission of high intensity light such that it penetrates the translucent egg and gives indications of embryonic position and development. When monitoring the development of other species, however, mixed results are obtained with this technique. For instance, the Emu egg is virtually opaque to transmitted visible light, and thus cannot be candled by traditional means. During the development cycle all avian embryos, and for that mater all egg-laying creatures, exhibit changes in shell surface temperatures that indicate on-going development, or a lack of that development. Additionally, such hazards as bacterial or viral growth within the shell produce atypical thermal signatures. Analysis of the shell surface temperatures may be useful in monitoring the development of these embryos. Further applications of IR thermography in farming of avian species may make it an economically viable monitoring technique.

Performance of IR building thermography has reached its limits in analyzing qualitative IR images only. Future progress could be traced in using new thermal pattern characterization algorithms applied both to quantitative static and dynamic IR images.

Railroad track failure, attributed to moisture trails and erosion voids in the rock ballast and subsoils that support the tracks, slowly deteriorate the railbed to a critical point in which iron rail shift occur. All railroad lines experience failures on a regular basis, but the recent Flood of '93, that inundated thousands of square miles of land and hundreds of miles of railroad tracks in the midwestern United States, brought a new impetus to quickly locate and repair these hidden subsurface defect areas. This paper illustrates a new technology combination of nondestructive remote sensing, computer-enhanced IR thermography and ground penetrating radar, that was used to detect buried moisture trails and erosion voids of railroad track beds. This technology combination is described in theory and by discussion of a case study based upon a successful project, conducted immediately following the flood, for Burlington Northern Railroad.

Justifying the costs of starting and maintaining an in-house IR thermography program is essential in ensuring continued funding and sponsorship. Cost benefit studies, whether brief and general, or strictly formalized, tend to focus on costs associated with projected equipment failure and production downtime. While these numbers can be quite dramatic, their validity rests on acceptance of the predicted failure which is inevitably the subject of some conjecture.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Analytical and experimental research has been conducted to assess the feasibility of detecting and diagnosing deep cracks in concrete dams by means of IR Thermography measurements. A simplified scale-down model of the nonoverflow section in a conventional concrete gravity dam and its reservoir has been designed with the capability of simulating both air-filled and water-filled deep cracks. A high-resolution CMT thermal imager (BSI 7000 equipment) has been utilized for mapping the temperatures at the downstream face of the latter model, under realistic quasi-static thermal conditions, in similar situations both with and without deep cracks present in the concrete body. The results obtained from these measurements compare reasonably well with calculations based on an ad hoc one-dimensional heat-transfer model of the simulated dam-reservoir complex. Appropriate thermal correlations have been found that appear to indicate the feasibility of detecting and diagnosing both air-filled and water-filled deep cracks in concrete dams using IR Thermography. The operating requirements imposed on the IR Thermography equipment to be used, and the reliability of the above detection and diagnosis process have been explicitly addressed.

A methodology based on IR Thermography measurements is proposed to estimate real istic values of hardware failure rates corresponding to secondary failures that is those caused by past or present outoftolerance or abnormal operating conditions. The methodology allows the establishment of useful correlations between these failure rates and the corresponding relevant thermal patterns as mapped using IR Thermography. The methodology is applied to practical cases of secondary failures in typical electrical and mechanical components having to do with failure modes due to abnormal stress corrosion and friction. The application of this technique to fault and failure diagnosis and both Reliability Availability and Maintainability (RAM) Analysis and Probabilistic Risk Assessment (PEA) is also briefly discussed. 1.

A 10 micron imaging camera has been used to identify subtle and not-so-subtle thermal pollution of the near telescope environment at several large telescopes, and can also be used to monitor progress in eliminating such pollution. This paper reports some highlights of data taken at the Multiple Mirror Telescope (MMT), the Kitt Peak National Observatory (KPNO), and Cerro Tololo Inter-American Observatory (CTIO) 4 meter telescopes, and Canada-France-Hawaii (CFHT) 3.6 meter telescope on Mauna Kea, the McDonald Observatory 2.7 and 2.1 telescopes and the 5 meter telescope at Mt. Palomar. This portable television equipment was purchased by the MMT with funding from the National Science Foundation and can be made available with some trained technical assistance.