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The brick masonry of Pietrasanta bell tower in Naples. Knowledge and conservation of an iconic medieval building
Published in Claudio Modena, F. da Porto, M.R. Valluzzi, Brick and Block Masonry, 2016
In the diagnostics sector applied to cultural heritage non-destructive methods of analysis are crucial for evaluating criticalities not evident in an initial visual investigation. In 1993, the European Committee for Standardization (ECS) issued European standard EN 473/ISO 9712, published in Italy as UNI EN 473/ISO 9712, with the aim of establishing single, standardized operational protocols in the field of non-destructive diagnostic tests, such as thermography. It is a technique of non-destructive analysis based on the acquisition of infrared images through remote sensing, and yielding a two-dimensional display of the irradiation measurement. A thermal imaging camera detects radiation in the infrared range of the electromagnetic spectrum and performs measurements correlated with the emission of these radiations (Carbonara, 1996). The use of thermal imaging in the study of the Pietrasanta Bell Tower is of great interest because it makes possible to define more precisely the different morphological characteristics of the various materials making up the Bell Tower's external walls, the presence of discontinuities and the state of conservation of parts of it. First, a survey project was put in place to ascertain which parts of the monument needed to be investigated and what resources were needed to carry it out. Subsequently we analyzed the climatic conditions inherent to the context and focused in particular on the monument's exposure to sunlight, in order to understand what the ideal time of day. The ideal condition for the thermography inspection of the bell Tower is during the afternoon, when the façade was exposing to direct sunlight at least three or four hours.
Assessment
Published in Paul F. McCombie, Jean-Claude Morel, Denis Garnier, Drystone Retaining Walls, 2015
Paul F. McCombie, Jean-Claude Morel, Denis Garnier
Thermal imaging can reveal aspects of a wall’s construction that could not be discovered otherwise without dismantling. Temperature variations within the ground are much less than the variation in air temperature, as the ground acts as an insulator, and because of its heat capacity it can change temperature only slowly. At a metre depth, temperature changes during the course of a day are very unlikely to have any effect. Drystone retaining walls have earth resting against them, and so are connected with material that is at a more stable temperature than the face of the wall, which is exposed to the air, rain, and if it is facing in the right direction, to the heat of the sun. The temperature of stone in good contact with the retained soil will therefore be more stable than that of the surrounding stone which is not. A through-stone that extends from the retained fill right to the face will be the most stable. When the air temperature is lower than the ground temperature, the face of such stones will be warmer than the face of surrounding stones and vice versa. Investigations have shown that this effect is clearest in the morning after a cold night. Later in the day, once the air has warmed up, especially if the sun is shining on the face of the stones, the stone with better contact with the soil may be cooler than the surrounding stone, but the thermal conductivity of individual stones plays a larger role. The surface of the stones may heat up to similar temperatures in the sun, and the effect of the contact with the ground becomes secondary. As thermal imaging cameras may have a temperature resolution of 0.1°C, subtle differences can be detected. It should be noted that as we are only interested in temperature differences between objects in the same view, the absolute accuracy of temperature measurement does not matter.
Autonomous Vehicles for Infrastructure Inspection Applications
Published in Diego Galar, Uday Kumar, Dammika Seneviratne, Robots, Drones, UAVs and UGVs for Operation and Maintenance, 2020
Diego Galar, Uday Kumar, Dammika Seneviratne
Thermal imaging cameras are able to capture even very small differences in temperature, in the order of 0.1°C. The image presented by a thermal imaging camera is multicolored, with each color representing a different temperature. Different scales may be used, depending on the presented objects. Thermal imaging studies have many uses in many fields and can be a useful diagnostic tool in the analysis of the state of a building. Noninvasive methods are very important, for example, in historic buildings.
Thermal efficiency enhancement using a ceramic coating on the cylinder liner and the piston head of the IC engine
Published in International Journal of Ambient Energy, 2021
P. Anand, D. Rajesh, M. Shunmugasundaram, I. Saranraj
A thermal imaging camera (colloquially known as a TIC) is a type of a thermographic camera used in firefighting. By rendering infrared radiation as visible light, such cameras allow firefighters to see areas of heat through smoke, darkness, or heat-permeable barriers. Thermal imaging cameras are typically handheld but may be helmet-mounted. They are constructed using heat- and water-resistant housings, and ruggedised to withstand the hazards of fire ground operations (Gatowski 1990). While they are expensive pieces of equipment, their popularity and adoption by firefighters in the United States are increasing markedly due to the increased availability of government equipment grants following the September 11 attacks in 2001. Thermal imaging cameras pick up body heat, and they are normally used in cases where people are trapped where rescuers cannot find them. A thermal imaging camera consists of five components: an optic system, detector, amplifier, signal processing, and display. Fire-service specific thermal imaging cameras incorporate these components in a heat-resistant, ruggedised, and waterproof housing (Miyairi et al. 1989). These parts work together to render infrared radiation, such as that given off by warm objects or flames, into a visible light representation in real time. The camera display shows infrared output differentials, so two objects with the same temperature will appear to be the same ‘colour’. Many thermal imaging cameras use greyscale to represent normal temperature objects, but highlight dangerously hot surfaces in different colours.
Investigation of intermittent microwave convective drying (IMCD) of food materials by a coupled 3D electromagnetics and multiphase model
Published in Drying Technology, 2018
Chandan Kumar, M. U. H. Joardder, Troy W. Farrell, M. A. Karim
A Flir i7 thermal imaging camera was used to capture the temperature distribution on the sample surface. Accuracy of measurement of temperature by thermal imaging camera depends on the emissivity values of the sample. The emissivity value for apple was found in the range between 0.94 and 0.97[67]; therefore, an average value of 0.95 was set in the camera before taking images.
Machinability analysis during finish turning Ti6Al4V with varying cutting edge radius
Published in Materials and Manufacturing Processes, 2023
Joyson Selvakumar S, Samuel Raj. D
The composition (weight %) of the Ti6Al4V alloy is tabulated in Table 1. The workpiece used was in the form of a 40 mm rod, 300 mm in length. An HMT semi-automatic machine with rated motor power of 7.5 kW and a maximum rotating speed of 2000 rpm was used for the finish turning experiments. The depth of cut (d), cutting speed (Vc) and feed rate (f) were chosen as 0.1 mm, 110 m/min, and 0.2 mm/rev respectively. A square WC insert (SNMG 120408) fixed on a tool holder (WIDAX PSBNR2020K12) with rake and lead angles of −6° and 15°, respectively, was used. The holder with cutting WC insert was fixed on the Kistler 9257B dynamometer to measure the process forces and moments in three axes (X, Y and Z directions) during machining. The forces measured using a dynamometer in the X-Y-Z axis are considered as feed (Ff), radial (Fr) and cutting (Fc) force components, respectively. The thrust force is calculated from the resultant of forces in the X and Y directions (i.e. resultant of feed (Ff) and radial (Fr) forces). To measure the temperature at the machining zone, an infrared thermal imaging camera (FLIR T540) was used. Temperature measurements were made with a thermal imaging camera that had a rated accuracy of 2%. The material emissivity values were obtained after several comparative measurements by heating the workpiece to different temperatures and measuring the surface temperature at a point using a K-type thermocouple and comparing these values with those provided by the IR camera where the emissivity was adjusted to provide the best match with the values measured using the thermo-couple. Since the chip flow obscures the hottest portion of the tool–chip interface, the maximum temperature measured (recorded) in the camera at any instant can be assumed to be the maximum temperature on the chip’s free surface. The chips mounted in cold setting resin were prepared and polished to measure the serration height (ts) and core thickness (tc) of the chip using OLYMPUS measuring microscope. SURFCOM 1500 SD3 with ACCTee measurement software is utilized to measure the chip segmentation height (Pt) on the chip-free surface and surface roughness (Ra) of machined surface. The stylus traces over the peak and valley on the chip’s surface. The segmentation height (Pt) value and its profile can be analyzed using the software. Multiple traces were done on the free surfaces of several chips, and the average value was used to determine the chip segmentation height (Pt).