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In this work the influence of the microstructure at the vicinity of the interface on the fracture behavior of particulate-reinforced aluminum alloy matrix composites (Al/SiCp composites) is studied by using thermographic tools. In particular, infrared thermography was used to monitor the plane crack propagation behavior of the materials. The deformation of solid materials is almost always accompanied by heat release. When the material becomes deformed or is damaged and fractured, a part of the energy necessary to initiate and propagate the damage is transformed in an irreversible way into heat. The thermal camera detects the heat wave, generated by the thermo-mechanical coupling and the intrinsic dissipated energy during mechanical loading of the sample. By using an adapted detector, thermography records the two dimensional "temperature" field as it results from the infrared radiation emitted by the object. The principal advantage of infrared thermography is its noncontact, non-destructive character. This methodology is being applied to characterise the fracture behavior of the particulate composites. Infrared thermography is being used to monitor the plane crack propagation behavior of such materials. Furthermore, an innovative approach to use microscopic measurements using IR microscopic lenses was attempted, in order to enable smaller features (in the micro scale) to be imaged with accuracy and assurance.

Up to now, the sun-pulse recorded during the heating (day) and cooling (night) phases has not yet been analyzed by using the infrared thermography (IRT) method through the complex wavelet transform (CWT) technique. CWT can be used with the sun-pulse data in a similar way as the discrete Fourier transform (DFT). In addition, CWT preserves the time information of the signal both in the phasegrams and in the amplitudegrams . In this work, a mosaic sample containing artificial flaws positioned at different depths was inspected into the long wave IR spectrum. It is possible to observe that by comparing defective and defect-free areas, a difference in phase during the thermal diffusion appears. The signal reference, measured on the defect-free area, was subtracted from the other measurement points. The resulting signal thermal contrast, representing the difference of the temporal evolutions of the surface temperature above the defective and defect-free positions, was also plotted. Subsequently, the wavelet phase contrast was computed. The solar radiation influencing the sample was estimated bearing in mind the sun path in the sky, the mosaic orientation and the inclination with respect to its local geographical coordinates. Finally, the ambient parameters have been recorded by a control unit. Although the CWT technique did not provided a sound visualization of the shape of the flaws, it permitted to reflect on the heat release coming from the bituminous material behind the statumen layer. Indeed, it is not atypical to find inclined mosaics to be restored.

This paper reports significant results about the effects of repeated treatments to protect a mediaeval Italian mortar from capillarity-absorbed water, by using for the treatments, our no-commercial hydro-alcoholic suspensions ofcalcium hydroxidenanoparticles(nanolime). The mortars samples came from the historical site, where preliminary thermographic inspection were performed to detect the damp zones. Before treatments, the samples were analyzed from a mineralogical and chemical point of view, by means of several techniques, asoptical microscopy(OM), thin section observations (PFM), porosimetric investigations, X-ray fluorescence (XRF), X-ray diffraction (XRD),infrared spectroscopy(FT-IR) and thermal analysis (TG-DTA). The size-grading curve of the aggregate and the binder/aggregate ratio were examined too. Then, the efficacy of nanolime protective treatments on this mortar versus the nanolime concentrations was investigated. For this aim, capillarity tests as well as porosimetric investigations, before and after the treatments, were performed. The obtained results were remarkably promising both in terms of the reduction of water absorbed by capillarity (up to 60%) together with an adequate decrease of porosity (up to 23%), fixing the protective effect of such eco-friendly and very compatible approach.

In this paper, chemical and structural studies of medieval wall paintings in Ocre (L’Aquila, Italy) are presented. During the latest restoration campaign, non-destructive (Near-Infrared Reflectography and Infrared Thermography) and micro-invasive (Nuclear Magnetic Resonance, Fourier Transform Infrared Spectroscopy, μ-Raman, Scanning Electron Microscopy with X-ray Microanalysis, X-Ray Diffraction, X-Ray Fluorescence, Optical Microscopy, Mass Spectrometry, Thermogravimetry) analyses were performed in order to determine the detachments of wall surfaces and the characterization of original and restoration materials. Data integration allowed to reconstruct the conservative history, the execution techniques and the conservation problems of the artefact, as well as to assess the effectiveness of restoration activities adopted. The combined use of physical and micro-chemical techniques proved to be effective for an in-depth study of materials stratification of paintings.

In this work, the use of advanced thermographic techniques for the post-impact defect detection in basalt fibre reinforced composite laminates was investigated. The laminates were previously impacted at different energies, namely 7.5, 15 and 22.5 J and then subjected to accelerated environmental aging or to a coating process in order to conceal the previous damage due to low velocity impact. In both cases the defects could be identified using infrared thermography in the mid-wave infrared (MWIR) spectrum even after the treatments. In addition, short-wave infrared (SWIR) results were employed with the aim to clearly identify unsuspected resin-rich areas. Therefore, the non-thermal part of the infrared spectrum (SWIR) can be coupled with the thermal part (MWIR) providing a complete infrared vision beyond what is perceptible to the naked eye, i.e., in the visible spectrum.

Damage following static indentation of jute/hemp (50 wt.% total fiber content) hybrid laminates was detected by a number of nondestructive testing (NDT) techniques, in particular, near (NIR) and short-wave (SWIR) infrared reflectography and transmittography, infrared thermography (IRT), digital speckle photography (DSP), and holographic interferometry (HI), to discover and evaluate real defects in a laminate with a complex structure. A comparative study between thermographic data acquired in the mid- (MWIR) and long-wave infrared (LWIR) spectrum bands, by pulsed (PT) and square pulse (SPT) thermography, is reported and analyzed. A thermal simulation by COMSOL® Multiphysics (COMSOL Inc., Burlington, MA, USA) to validate the heating provided is also added. The robust SOBI (SOBI-RO) algorithm, available into the ICALAB Toolbox (BSI RIKEN ABSP Lab, Hirosawa, Japan) and operating in the MATLAB® (The MathWorks, Inc., Natick, MA, USA) environment, was applied on SPT data with results comparable to the ones acquired by several thermographic techniques. Finally, segmentation operators were applied both to the NIR/SWIR transmittography images and to a characteristic principal component thermography (PCT) image (EOFs) to visualize damage in the area surrounding indentation.

Holographic and thermographic techniques have been recently applied in artwork diagnostics for the quantitative evaluation of defect size and depth in laboratory samples of artworks. The aim of this study is a comparison between holographic interferometry (both double exposure and real time), and pulsed thermography (PT) processing techniques such as differential absolute contrast (DAC) and pulsed phase thermography (PPT) for the detection of the subsurface flaws on wooden panel paintings. The performance of holographic techniques can be reserved for investigation of particular defects (cracks, detachments) at incipient stages, where high resolution/sensitivity is required, while PT can provide interesting quantitative results in situ.

In this study, experimental data from two artwork specimens was acquired and processed by pulsed phase thermography (PPT) and holographic interferometry. The first specimen was a wood painting with a variety of damages typical of this kind of pieces. A comparative study between thermography and interferometry results showed the potential complementarities of both techniques. The second inspected specimen was a fresco with fabricated inserts inspected by PPT to detect and characterize the subsurface defects. The well-known concept of Signal-to-Noise Ratio (SNR) is proposed for the selection of the proper phasegram frequency at which defect sizing is performed. A de-noising step was required prior to the application of the Canny edge detection algorithm. It is demonstrated with this investigation that PPT and holographic interferometry are valuable tools for the qualitative and quantitative assessment of artworks.

Infrared (IR) vision for the nondestructive testing (NDT) of materials has considerably grown in the last few years as a results of the continual technological progress and the development of advanced signal processing techniques. Typical applications can be divided into two groups: (1) reflectography/transmittography in the near (NIR) and short-wave (SWIR) infrared spectra, which have been recently applied in the inspection of semitransparent composite materials such as glass, aramid-phenolic, and a variety of natural fibers; and (2) infrared thermography, which involves the detection of surface and subsurface defects based on the differences in thermal signatures in the mid-wave (MWIR) and long-wave (LWIR) infrared bands. Infrared reflectography and thermography have shown interesting complementarities between them as well as with other NDT methods such as ultrasound testing, eddy current testing, and holographic interferometry. In this chapter, a review of classical and recent applications of infrared vision is provided and discussed in detail with examples., Series: Advances in Computer Vision and Pattern Recognition

The main goal of this work was the non-destructive testing (NDT) of an ancient fresco (15th century) preserved in the Santa Maria di Collemaggio Church (L’Aquila, Italy) and damaged after the 2009 earthquake. Active infrared thermography (IRT), near-infrared (NIR) reflectography and ultraviolet imaging (UV) were used. In addition, the state of the fresco prior to the earthquake was analyzed by electronic speckle pattern interferometry (ESPI), digital speckle correlation (DSC), raking light, tap, and chemical NDT techniques. The use of these techniques was important for the monitoring of new damages and for a comparison between the results over the years. Square heating thermography (SHT) data were processed using principal component thermography (PCT) and pulsed phase thermography (PPT) algorithms, in order to improve the defects’ signature and to reduce the impact of non-uniform heating and emissivity variations due to the painting’s pigments. A multi-analysis approach, segmentation operators and a speci...

Energy consumption of buildings could be significantly reduced by improving the efficiency of the envelope. Currently, the estimation of the energy performance of existing buildings requires the knowledge of the overall heat transfer coefficient (U-value) of the walls. U-values can be calculated through a theoretical approach, knowing the thermal conductivity and thickness of each material that constitutes the wall stratigraphy, from project data or coring. Alternatively, U-values can be obtained experimentally, through the ISO recommended heat flow meter measurements. Although generally accepted, the heat flow meter method suffers from some disadvantages. Recently, an alternative approach based on infrared thermography (IRT) has been proposed for in situ measurements. Main advantages of this new approach are non invasivity and the possibility of inspecting relatively large areas in real time. In this paper, after a brief description of the state of the art in the field of U-value measurement by IRT, a case study is described. In particular, the results obtained by IRT on an existing building are compared with U-values given by the standard ISO calculation and heat flow meter measurements; advantages and limitations of the new method are outlined. Some suggestions for a successful exploiting of the IRT approach are also given.

Among the several issues to be considered during fresco’s restoration, the understanding of the effectiveness of the intervention, the identification of the main chemical elements used in previous restorations and the attention to weak areas of the building structure, adjacent to frescoes, are of paramount importance. This work describes an integrated, non-destructive testing approach focusing on these three main issues. In particular, two frescoes of Giacomo Farelli are analyzed herein. These artworks were affected by a strong earthquake in 2009, which had a heavy impact on several cultural heritage objects in L’Aquila (Italy), including on the Santa Maria della Croce di Roio Church (1625), where these two frescoes are located. One of the frescoes, which underwent a restoring before the quake, was previously tested by electronic speckle pattern interferometry (ESPI) before and after the restoration. These previous results are compared with new measurements carried out after the 2009 earthquake using infrared thermography (IRT). The combined approach, ESPI-IRT, clearly highlighted that the structure of the frescoes was significantly affected by the earthquake, since the old subsurface cracks, restored before 2009, were once again evident after the earthquake. In addition, the presence of a subsurface niche containing an ancient statue, also detected by means of IRT, might contribute to increase the severity of the damages. Finally, the joint examination of these frescoes using near-infrared reflectography and X-ray diffractometry was crucial to confirm the presence of a radioactive chemical element in the wall painting.

Natural fibers constitute an interesting alternative to synthetic fibers, e.g. glass and carbon, for the production of composites due to their environmental and economic advantages. The strength of natural fiber composites is on average lower compared to their synthetic counterparts. Nevertheless, natural fibers such as flax, among other bast fibers (jute, kenaf, ramie and hemp), are serious candidates for seismic retrofitting applications given that their mechanical properties are more suitable for dynamic loads. Strengthening of structures is performed by impregnating flax fiber reinforced polymers (FFRP) fabrics with epoxy resin and applying them to the component of interest, increasing in this way the load and deformation capacities of the building, while preserving its stiffness and dynamic properties. The reinforced areas are however prompt to debonding if the fabrics are not mounted properly. Nondestructive testing is therefore required to verify that the fabric is uniformly installed and that there are no air gaps or foreign materials that could instigate debonding. In this work, the use of active infrared thermography was investigated for the assessment of (1) a laboratory specimen reinforced with FFRP and containing several artificial defects; and (2) an actual FFRP retrofitted masonry wall in the Faculty of Engineering of the University of L’Aquila (Italy) that was seriously affected by the 2009 earthquake. Thermographic data was processed by advanced signal processing techniques, and post-processed by computing the watershed lines to locate suspected areas. Results coming from the academic specimen were compared to digital speckle photography and holographic interferometry images.

An integrated system between infrared vision and optical non-destructive testing techniques can be considered a viable, robust and reliable approach for both aerospace manufacturing and in-service inspections. In this paper, infrared vision is applied in different spectral bands on two impacted panels made of aramid–phenolic composite by applying two different methods, respectively: (1) near and short-wave infrared reflectography and transmittography, and (2) mid-wave active infrared thermography. Furthermore, optical methods, namely digital speckle photography and holographic interferometry, are used as well to highlight the damages due to the impacts on the samples. Some techniques provide more straightforward detection capabilities than others for different defect types.

Conserving architectural heritage usually requires a multidisciplinary approach involving a variety of professionals and organizations. Since the evaluation of the state of conservation of historical buildings using destructive techniques should be avoided to prevent the integrity of the cultural heritage, the development of non-destructive and non-contact techniques is very important. InfraRed (IR) thermography is a non-destructive powerful tool for fast and accurate building diagnostics. In the investigation of historical structures, where a restoration or conservation treatment can cause irreversible damage to the structure, it is considered to be of most importance. A campaign of thermographic surveys were conducted on a large part of the historical cultural heritage of L’Aquila and its surroundings. In this paper we present the results of the study for the Church of Santa Maria ad Cryptas (XIII century), one of the most ancient buildings in the surroundings of L’Aquila and one of the best examples of Gothic art in Abruzzo, with the aim to evaluate the correspondence between the damage induced by the earthquake and the previous thermographic results, in order to validate the effectiveness of thermography and its role in preventive diagnosis.

A limited number of comparative studies on falling weight impact properties of different composites exist, especially using non-destructive techniques (NDTs). In this work, two types of woven fabric composites, reinforced respectively with E-glass fibres and basalt fibres, were subjected to low velocity impact at different energies (7.5, 15 and 22.5 J). Comparative indications were offered by impact hysteresis cycles and the integration of data between different enhanced vision methods, namely interferometric and IR thermographic techniques. The integrated application of these techniques suggests that the increased directionality of impact damage observed in basalt fibre reinforced composites, though their impact performance appears to be slightly superior, may represent a limitation on the predictability of their behaviour.

Up to now, infrared thermographic approaches have been considered either passive or active. In the latter case, the heat flux is historically attributed to a non-natural heat source. The use of the sun has recently been incorporated into the active approach thanks to multi-temporal inspections. In this paper, an innovative hybrid thermographic (HIRT) approach is illustrated. It combines both the time component and the solar source to obtain quantitative information such as the defect depth. Thermograms were obtained by inspecting the facade of the Santa Maria Collemaggio church (L’Aquila, Italy), whereas quantitative results related to the sub-superficial discontinuities were obtained thanks to the use of advanced techniques. Experimental results linked to passive approach (i.e., the mosaicking procedure of the thermograms) performed by selecting a set of historic churches are also included in order to explain, when and where, the hybrid procedure should be used.

In this research work, experimental procedures by means of Transient Thermography and Holographic Interferometry were performed in order to detect subsurface tesserae areas of plastered mosaics. A mosaic sample consisted of various types of tesserae and covered with hydraulic lime mortar was evaluated in the laboratory with various transient thermal processing techniques such as Pulsed Phase Thermography, Thermographic Signal Reconstruction and Principal Component Thermography, as well as Holographic Interferometry in both real-time and double-exposure configurations. Results from the non-invasive investigation are presented and discussed, revealing that the above approaches can obtain a seeing through investigation of plastered mosaics.

The 33rd UIT (Italian Union of Thermo-Fluid Dynamics) Heat Transfer Conference was organized by the Dept. of Industrial and Information Engineering and Economics, University of L'Aquila (Italy) and was held at the Engineering Campus of Monteluco di Roio, L'Aquila, June 22-24, 2015. The annual UIT conference, which has grown over time, came back to L'Aquila after 21 years. The scope of the conference covers a range of major topics in theoretical, numerical and experimental heat transfer and related areas, ranging from energy efficiency to nuclear plants. This year, there was an emphasis on IR thermography, which is growing in importance both in scientific research and industrial applications. 2015 is also the International Year of Light. The Organizing Committee honored this event by introducing a new section, Technical Seminars, which in this edition was mainly devoted to optical flow visualization (also the subject of three different national workshops organized in L'Aquila by UIT in 2003, 2005 and 2008). The conference was held in the recently repaired Engineering buildings, six years after the 2009 earthquake and 50 years after the beginning of the Engineering courses in L'Aquila. Despite some logistical difficulties, 92 papers were submitted by about 270 authors, on eight different topics: heat transfer and efficiency in energy systems, environmental technologies and buildings (32 papers); micro and nano scale thermo-fluid dynamics (5 papers); multi-phase fluid dynamics, heat transfer and interface phenomena (16 papers); computational fluid dynamics and heat transfer (15 papers); heat transfer in nuclear plants (6 papers); natural, forced and mixed convection (6 papers); IR thermography (4 papers); conduction and radiation (3 papers). The conference program scheduled plenary, oral and poster sessions. The three invited plenary Keynote Lectures were given by Prof. Antonio Barletta (University of Bologna, Italy), Prof. Jean-Christophe Batsale (Arts et Metiers Paris Tech, Talence, France) and Prof. Walter Grassi (University of Pisa, Italy). The two invited Technical Seminars were given by Dr. Maurizio Santini (University of Bergamo, Italy) and Prof. Giovanni Tanda (University of Genova, Italy). There were also 13 oral sessions and three poster sessions. This special issue collects the five papers presented in the plenary sessions (keynote lectures and technical seminars) plus 60 papers selected from those presented and discussed during the congress. The UIT 2015 conference has been a useful occasion to stimulate discussion, further the understanding of heat transfer and related phenomena, present the state-of-the-art of some topics, discuss emerging trends and promote collaborations. We hope this issue will maintain and extend some of these features. A special thank you is due to the Organizing and Scientific Committees, to the sponsors and to all the participants.

One of the key parameters that "meter" the energy performance of the whole structure of buildings is the thermal transmittance.This parameter can be evaluated with a theoretical approach, regulated by standard ISO 6946, once the stratigraphy of the envelope and the properties of the constituent materials are known, or by using a heat flow meter (HFM), following the recommendations provided in standard ISO 9869.Recently, the use of quantitative IR Thermography (IRT) has been proposed by several researchers; this method allows to determine the overall transmittance of an envelope in a short time (especially in comparison with HFM method). However, the theoretical or experimental transmittance, measured on real buildings having walls composed by different materials, can be rather distant from those calculated or measured with different procedures.For this reason, for a correct certification of the thermal performance of a building envelope, it is necessary the availability of experimental procedures for a direct and reliable evaluation of the thermal transmittance, suitable for different walls.Research has found that, especially in historical constructions, faults in the building envelope and the age of the materials can greatly affect the HFM measurements.The aim of this work is to analyze in situ the thermal performance of three different walls which have been selected according to: different materials, different age, and different construction. On each envelope, a comparison between U-values, measured by HFM and IRT, and computed according the standard procedure, has been effected.

The durability of an exterior finish is affected by the characteristics of the wood. Satisfactory finish life is usually more difficult to achieve on woods of higher density. All wood shrinks as it loses moisture and swells as it absorbs moisture, but some species are more stable than others. Species that shrink and swell the most cause more stress on paint films than woods that are more stable [1]. To this end, let us recall that a painting on wood can be considered as a layered structure: The wood support is coated with a number of superposed priming layers made from mixtures of gesso and glue. A frequent fault resulting from such a system is the formation of detached regions inside the layered structure caused by the shrinkage process of the wood support [2]. Obviously, wood deteriorates more rapidly in warm, humid regions with respect to cool or dry places [3]. The influence of wood conditions on surface coatings is a critical point that should be monitored and that depends on environmental parameters such as microclimate. To prevent and control the effects, keeping costs down, a non-destructive monitoring of wood support behavior under thermal stress is needed. In this work, an integrated approach based on traditional and innovative (HI, PT and NIR) techniques was conducted on a primed support of poplar wood with a complex-shape surface containing areas of artificial defects at several depths due to the influence of the support on the various layers. The obtained results could be arranged, if integrated into a multidisciplinary approach, in order to define and design the conservation of the wooden artifacts.

Advanced ceramic materials are increasingly employed in varied and new applications where improved electrical, mechanical and/or thermal properties are sought. For instance, in a manner similar to carbon or glass fiber reinforced plastics, ceramic matrix composites (CMCs) are designed to improve the naturally brittle characteristics of monolithic ceramics thanks to the inclusion of fibers. Among the main interests for advanced ceramics are the increase in the operation temperature of components, the elimination of the use of cooling fluids, and weight savings. In this paper, the capabilities of infrared thermography and holographic interferometry are investigated and compared for the nondestructive assessment of advanced ceramic materials using three experimental specimens: (1) a monolithic green ceramic tile with fabricated defects, (2) a CMC specimen (from production reject) with a porous alumina matrix reinforced with glass fibers, and (3) a sandwich structure consisting on a carbon fiber honeycomb core with a ceramic plate bonded in one side.

Ceramics are inorganic materials fabricated by a high-temperature chemical reaction. Most ceramics are oxides, but the term is also used for silicides, nitrides and oxynitrides, hybrids and other inorganic materials. It is convenient to consider ceramics that are essentially silicates, called traditional ceramics, separately from all of the others. In the ceramic industry testing systems are seldom employed for detecting on-line the presence of defects in ceramic tiles. Defects in the ceramic body are usually originated during the pressing stage due to the incorrect use of process parameters or to the improper selection of raw materials. These defects are generally characterized by the inclusion of heterogeneous materials or agglomerates, which decreases the structural strength jeopardizing the final quality of the produced piece. Disagreeable repercussions on the sale market, especially on higher-quality ceramics such as porcelain, are characterized by the lack of specific nondestructive testing (NDT) techniques that “certify”, pre-emptive, the quality of the produced piece. The integration of IRT and HI for the NDT of a green ceramic tile with both fabricated and real defects (cracks caused by the natural shrinkage process), allowed us to produce a clear “defects map”.

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.

In this work the possibility of modeling manufacturing ceramic products is analyzed through the application of transient thermography, holographic interferometry and digital speckle photography, in order to identify the subsurface defects characteristics. This integrated method could be used to understand the nature of heterogeneous materials (such as plastic, sponge simulating a void, wood, aluminum) potentially contained within ceramic materials, as well as to predict crack formation due to them. The paper presents the analysis of green ceramic tile containing defects of different types and sizes located at different depths. The finite element method is used for solving the problem of transient heat transfer occurring in experimental conditions. Unknown parameters of the numerical model (such as convective heat transfer coefficients and sample surface emissivity) were adjusted to obtain numerical simulation results as close as possible to those obtained experimentally. Similarities and differences between experimental and simulated data are analyzed and discussed. Possibilities for improving the results and further developments are proposed.

The monitoring of heritage objects is necessary due to their continuous deterioration over time. Therefore, the joint use of the most up-to-date inspection techniques with the most innovative data processing algorithms plays an important role to apply the required prevention and conservation tasks in each case study. InfraRed Thermography (IRT) is one of the most used Non-Destructive Testing (NDT) techniques in the cultural heritage field due to its advantages in the analysis of delicate objects (i.e., undisturbed, non-contact and fast inspection of large surfaces) and its continuous evolution in both the acquisition and the processing of the data acquired. Despite the good qualitative and quantitative results obtained so far, the lack of automation in the IRT data interpretation predominates, with few automatic analyses that are limited to specific conditions and the technology of the thermographic camera. Deep Learning (DL) is a data processor with a versatile solution for highly automated analysis. Then, this paper introduces the latest state-of-the-art DL model for instance segmentation, Mask Region-Convolution Neural Network (Mask R-CNN), for the automatic detection and segmentation of the position and area of different surface and subsurface defects, respectively, in two different artistic objects belonging to the same family: Marquetry. For that, active IRT experiments are applied to each marquetry. The thermal image sequences acquired are used as input dataset in the Mask R-CNN learning process. Previously, two automatic thermal image pre-processing algorithms based on thermal fundamentals are applied to the acquired data in order to improve the contrast between defective and sound areas. Good detection and segmentation results are obtained regarding state-of-the-art IRT data processing algorithms, which experience difficulty in identifying the deepest defects in the tests. In addition, the performance of the Mask R-CNN is improved by the prior application of the proposed pre-processing algorithms. Ministerio de Ciencia, Innovación y Universidades (España) | Ref. FPU16/03950 Universidad de Salamanca | Ref. Cátedra Iberdrola VIII Centenario

The present work aims at investigating a new challenging use of oxide (TiO2, Al2O3, etc.) nanoparticles to enhance the thermal properties: thermal conductivity, specific heat, and latent heat of pure paraffin waxes to obtain a new class of Phase Change Materials (PCMs), the so-called nano-PCMs. The nano-PCMs were obtained by seeding different amounts of oxide nanoparticles in a paraffin wax having a melting temperature of 45°C. The thermophysical properties such as latent heat and thermal conductivity were then measured to understand the effects of the nanoparticles on the thermal properties of both the solid and liquid PCM. Finally, a numerical comparison between the use of the pure paraffin wax and the nano-PCM in a typical electronics passive cooling device was implemented. Numerical simulations were carried out using the Ansys-Fluent 15.0 code. Results in terms of solid and liquid phase temperatures, melting time and junction temperature were reported. Moreover, a comparison with experimental results was also performed.