1,721,036 research outputs found
IR Thermography of Ancient Art Monuments
No full textBoth passive and active methods of infrared thermography have been used to analyze air/wall temperature and humidity, as well as wall fresco defects, in two Italian churches. Results of experimental analysis and numerical simulation are presented
Sportswear textiles emissivity measurement: comparison of IR thermography and emissometry techniquBison, P.a, Grinzato, E.a, Libbra, A.b, Muscio, A.
No full textThree sportswear textiles are compared, one normal and two 'special' with Ag+ ions and Carbon powder added, with different colors. The emissivity of the textiles has been measured to determine if it is increased in the 'special' textiles with respect to the normal one. The test implied some non-standard procedure due to the semitransparent nature of the textiles, in comparison with the normal procedure that is commonly used on opaque surfaces. The test is also carried out by a standard emissometry technique, based on a comparative approach with reference samples having known thermal emissivity. The results are compared and discussed
Automatic U-value measurement by local thermographic analysis
No full textThe measurement of U-value is an important issue for energy budget evaluation, but conventional techniques are not satisfactory. To date, IR thermography has barely been used for a qualitative measurement or to support other standardized measuring. The proposed method is able to very accurately detect the temperature difference between the air and a surface. The instantaneous heat flux through the inner surface of a room is monitored starting from a local mapping of such data. The improvements detailed in this paper include the evaluation of both convective and radiative heat flux on a local basis with a space resolution of 1 cm. In particular, the surface heat exchange coefficient is evaluated with a fast algorithm. A steady thermal state, with the help of the outside air temperature, allows for the thermal performance evaluation of the building envelope. In the case of a transient condition, an averaging process or a system identification algorithm must be applied on time-series of such data. An automatic procedure has been set up in order to accomplish this recording. In either case, it is shown that a conventional technique based on heat flux metering for the U-value measurement is much less informative about critical points than quantitative IR thermography. Tests in situ are reported and compared with results obtained both by the standard methods for measurement and computation
R-value estimation by local thermographic analysis
No full textIR thermography applied in a proper way is able to detect very accurately temperature difference between air and surfaces. By means of this tool is now possible to analyse the local instantaneous heat flux through the surface of a building. In case of steady thermal state, this gives the thermal performance evaluation of the building envelope. In case of a transient condition an averaging process or a system identification algorithm must be applied on time-series of such a data. In any case, it is demonstrated that a standard technique based on thermal flux meter for the thermal resistance (R-value) measurements is more affected by errors than thermographic measurements using this new approach. The method is illustrated with experimental results obtained into a residential building. A dedicated thermographic apparatus is used to map the temperature of the indoor surface of an internal wall and to measure in same positions the air temperature at 10 cm from the surface. From these data the local heat flux is detected at any point of the internal surface. A conventional thermogram of the corresponding outside surface or the outdoor air temperature history allows an easy way to achieve both thermal conductance and transmittance of the investigated wall. In this way it is possible the evaluation of both radiative and convective heat flux on a local basis with a space resolution of 1 cm. The results are here presented within a comparison with the local measurement with a thermal flux-meter device. These results are important in order to enhance energy efficiency and comfort in buildings
Automatic Indoor Environmental Conditions Monitoring by IR Thermography
No full textThis paper presents a new approach to moni- tor an indoor environment on thermodynamic basis. It uses temperature as the driving parameter and is especially suited for comfort analysis or evaluation of moisture. The method is based on infrared (IR) thermography, which proved to be very effective in this application. The system measures all fundamental environment parameters (e.g., air temperature, relative humidity and air speed) by imaging with a thermal camera a set of special targets arranged in a grid, which can be placed close to a wall or in any other place of the room . At the same time, the system images the wall surface behind the grid and so can measures the wall’s temperature, as well. The thermal camera was mounted on a pan-til unit to realize the monitoring process in an automatic way. The core of the device is a software that can process the thermal images on- line and control the pan-tilt unit. A fast automatic learning procedure enables to recognize the special target on the grid also in challenging environments and in very different environment conditions. This coupled with the advanced features of modern off the shelve IR cameras allows effective and robust results. This paper illustrates the developed device (both the hard- ware and the software) and shows the current application of evaluating the decay risk of a heritage building covered by Italian renaissance frescoes. However, the presented approach can be applied in different applications, for instance: indoor environmental monitoring, energy saving, NDT of buildings, and information technology with geomatics
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
High resolution and automatic survey of buildings by IR thermography
No full textThe paper illustrates a new approach to achieve the temperature distribution of a buildings composing a global view,
at high resolution. It starts from the state of the art and describes how to manage the thermograms content. The on line
radiometric calibration of raw thermograms allows obtaining a high accuracy of temperature readings. The calibration is
performed using a grid of special targets viewed by the thermographic camera.
An accurate global view of the building envelope is produced with images of thousands per thousands pixels trough
an automatic mosaic composition of thermograms. Advanced image processing, including the geometric correction is
performed in real time. The final result is a 3D model of the building, georeferenced and with capability to perform heat flux
measurements.
In addition, IR images, Near IR and visible electromagnetic bands are fused for the building material evaluation.
As case study, the exterior surface of Palazzo Ducale in Venice, is analyzed and illustrated
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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