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This paper presents a NDT by a CO 2 Laser infrared thermography applied to defect detection in CFRP. The CO 2 Laser is an infrared laser with the wavelength of 10.6 μm. This excitation has a controllable heating beam by a geometric relation D = 0.01575· d , which allows to heat the samples at a specific position (placed at the distance “ d ”) and area (of a diameter “ D ”). The PPT interpretation principle was used to reduce the non-uniformity’s effect of the excitation causing inhomogeneous heat. The test with this excitation is much faster than the tests with conventional lock-in thermography method. [ABSTRACT FROM AUTHOR]

This study presents a NDT method using infrared thermography associated with a microwave excitation. The advantages of such stimulation lie in the volumic absorption of incoming waves which lead to a greater sounded depth. This method is applied to two types of samples. The first is a concrete slab reinforced with CFRP on which a bonding failure is inserted and the second is a wooden plate on which a metallic insert is placed on the back face. The device generating the microwaves is made of a commercial magnetron associated with a pyramidal horn antenna. An infrared camera is placed on the same side as the stimulated surface and thermograms are recorded at regular intervals. The whole assembly is placed in a protective room against high frequencies. The incident power density leads to heating of less than 1 °C of the surface of the samples. The thermograms show a higher temperature rise in front of the defect area. The non-uniformity of the beam, leads us to treat the thermograms with an algorithm of contrast. These first results show the interest of the microwave excitation to detect defects deeper than in the case of surface excitation. [ABSTRACT FROM AUTHOR]

This paper presents a NDT by infrared thermography with a microwave excitation system. The advantages of such stimulation lie in the volumetric absorption of incoming waves which lead to a greater sounded depth. The device generating the microwaves was made of a commercial magnetron 800W at 2.45GHz associated with a pyramidal horn antenna. This method was applied to detect the steel reinforcements (deformed bar 12mm of diameter placing at every 10cm) in a concrete specimen (1m×1m×6.5cm) with a concrete cover of 3.8cm. The specimen was heated with an average power of 600W for 5min. An infrared camera was placed on the same side as the stimulated surface and thermograms were recorded at regular intervals. The whole assembly was placed in a protective enclosure against high frequency electromagnetic fields. The method based on a contrast algorithm was used to analyze the thermogram series. The result shows a higher temperature rise in front of the steel reinforcement areas. The effect of microwave caused an increase in moderate temperature does not lead to alteration of inspected concrete. [ABSTRACT FROM AUTHOR]

Natural stone is a traditional building material used worldwide for millennia. Its mechanical properties are rather well known, but only a small quantity of data is available regarding its hygrothermal characteristics. However, these characteristics are essential for the design of energy efficient buildings. Stones are in fact associated with insulation materials, which strongly modify the hygrothermal behavior of building walls, thereby impacting their durability and thermal comfort. This study focused on the hygrothermal characterization of a dozen samples of limestone, offering an adequate representation of their use across France. Thermal conductivity and heat capacity, sorption and desorption isotherms, water vapor permeability, and moisture buffer value (MBV) all were determined and analyzed. These data can be used to model heat and mass transfers in building walls. Limestone features extensive physical properties that can vary from one place to another within the same quarry. A statistical classification of the mechanical properties of thousands of French limestones was carried out. This classification allows estimating the hygrothermal properties previously determined for other stones. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article on the characteristics of limestones for energy-efficient and sustainable building components. The authors have identified errors in the original publication and have provided corrected values for certain measurements. The document includes a table with the corrected values for properties such as density, porosity, and thermal conductivity. The purpose of this correction is to ensure the accuracy of the published information. [Extracted from the article]

In a period of surging energy prices, resource depletion, and concerns over the use of nuclear power, energy savings are paramount and a major component of ongoing sustainable development. Geothermal energy is the energy stored in the form of heat beneath the surface of the Earth. Related to this, the thermal properties of soils are of great importance, particularly with regard to the modern trends of utilizing the subsurface for transmission of either heated fluids or high power currents. For example, in geothermal hydrology or geotechnical engineering applications, the thermal conductivity must be determined to assess the energy potential of the soil. The presence of water (groundwater, rainfall, natural moisture) improves both the thermal conductivity and thermal capacity fields. We present an original method-based on a thermal study and the use of non-integer order models-to determine the thermophysical parameters of different soils in near-surface layers, and link them to the water content variations of different soils. The results are compared with those obtained using a capacitive profile probe. [ABSTRACT FROM AUTHOR]