scholarly journals Inverse Contrast in Non-Destructive Materials Research by Using Active Thermography

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 835 ◽  
Author(s):  
Paweł Noszczyk ◽  
Henryk Nowak
Keyword(s):  
Oriented Strand Board ◽  
Front Surface ◽  
High Heat ◽  
Materials Testing ◽  
Active Thermography ◽  
Infrared Radiator ◽  
Depth Analysis ◽  
Materials Research ◽  
High Heat Capacity ◽  
Non Destructive

Background: it is undesirable for defects to occur in building partitions and units. There is a need to develop and improve research techniques for locating such defects, especially non-destructive techniques for active thermography. The aim of the experiment was to explore the possibility of using active thermography for testing large-sized building units (with high heat capacity) in order to locate material inclusions. Methods: as part of the experiment, two building partition models—one made of gypsum board (GB) and another made of oriented strand board (OSB)—were built. Three material inclusions (styrofoam, granite, and steel), considerably differing in their thermal parameters, were placed in each of the partitions. A 7.2 kW infrared radiator was used for thermally exciting (heating) the investigated element for 30 min. The distribution of the temperature field was studied on both sides of the partition for a few hours. Results: using the proposed investigative method, one can detect defects in building partitions under at least 22 mm of thick cladding. At a later cooling down phase, inverse temperature contrasts were found to occur—the defects, which at the beginning of cooling down were visible as warmer areas, at a later phase of cooling down are perceived as cooler areas, and vice versa (on the same front surface). In the transmission mode, the defects are always visible as areas warmer than defect-free areas. Moreover, a quantitative (defect location depth) analysis with an accuracy of up to 10% was carried out using the Echo Defect Shape method. Conclusions: active thermography can be used in construction for non-destructive materials testing. When the recording of thermograms is conducted for an appropriate length of time, inverse contrasts can be observed (on the same front surface).

Main Provisions Of The Concept Of Technology Of Diamond Cutting And Drilling Of Building Structures

2019 ◽  
pp. 59-63
Keyword(s):  
Combustion Engine ◽  
Front Surface ◽  
The Body ◽  
Building Structures ◽  
Diamond Cutting ◽  
Variable Diameter ◽  
Diamond Drilling ◽  
Single Structure ◽  
New Construction ◽  
Non Destructive

The main provisions of the concept of technology of diamond cutting and drilling of building structures are considered. The innovativeness of the technology, its main possibilities and advantages are presented. Carrying out works with the help of this technology in underwater conditions expands its use when constructing and reconstructing hydraulic structure. The use of diamond drilling equipment with motors equipped with an internal combustion engine is considered. Drilling holes with a variable diameter during the reconstruction of the runways of airfields makes it possible to combine the landing mats into a single structure. The ability to cut inside the concrete mass, parallel to the front surface, has no analogues among the methods of concrete treatment. The use of this technology for producing blind openings in the body of concrete without weakening the structure is also unique. Work with precision quality in cutting and diamond drilling of concrete and reinforced concrete was noted by architects and began to be implemented in the manufacture of inter-room and inter-floor openings. Non-destructive approach to the fragmentation of building structures allows them to be reused. The technology of diamond cutting and drilling is located at the junction of new construction, repair, reconstruction of buildings and structures, and dismantling of structures. Attention is paid to the complexity and combinatorial application of diamond technology. Economic efficiency and ecological safety of diamond technology are presented. The main directions of further research for the development of technology are indicated.

scholarly journals An overview on the non-destructive in-depth surface analysis of corrosion-resistant films: A case study of W-xCr deposits in 12 M HCl solution

BIBECHANA ◽  
2021 ◽  
Vol 18 (1) ◽  
pp. 201-213
Author(s):  
Jagadish Bhattarai
Keyword(s):  
Corrosion Resistance ◽  
Depth Profiling ◽  
Surface Films ◽  
High Corrosion Resistance ◽  
Corrosion Rates ◽  
High Corrosion ◽  
Depth Analysis ◽  
Sputter Deposited ◽  
Non Destructive ◽  
Hcl Solution

Non-destructive in-depth analysis of the surface films formed on the sputter-deposited binary W-xCr (x = 25, 57, 91 at %) alloys in 12 M HCl solution open to air at 30 °C was investigated using an angle-resolved X-ray photoelectron spectroscopic (AR-XPS) technique to understand the synergistic corrosion resistance effects of showing very low corrosion rates, even lower than both alloying metals of the deposits. The average corrosion rates of these three tungsten-based sputter deposits found to be more than five orders of magnitude (between 3.1 × 10−3 and 7.2 × 10−3 mm/y) to that of chromium and also nearly one order of magnitude lower than that of tungsten metals. Such high corrosion resistance of the sputter-deposited W-xCr alloys is due to the formation of homogeneous passive double oxyhydroxide film consisting of Wox and Cr4+ cations without any concentration gradient in-depth after immersion in 12 M HCl solution open to air at 30 °C from the study of the non-destructive depth profiling technique of AR-XPS. Consequently, both alloying elements of tungsten and niobium are acted synergistically in enhancing high corrosion resistance properties of the alloys in such aggressive electrolyte. BIBECHANA 18 (2021) 201-213

Safety Issues Concerning Robotic Welding of Large Elements

2015 ◽  
Vol 220-221 ◽  
pp. 818-823 ◽  
Author(s):  
Wojciech J. Klimasara ◽  
Zbigniew Pilat ◽  
Marcin Słowikowski
Keyword(s):  
Risk Factors ◽  
Health Risks ◽  
Occupational Safety ◽  
High Heat ◽  
Robotic Welding ◽  
European Directives ◽  
Safety Issues ◽  
Safety Regulations ◽  
High Heat Capacity ◽  
Welding Processes

Robotic welding of large elements poses significant difficulties regarding the technological process, robot functions and the safety of the operator and other people. The health risks involved arise out of the weight of elements, high heat capacity, harmful gases and fumes. Under the Eureka project, the PIAP team is developing a model of a robotized cell designed mainly for welding large elements. Occupational safety is of paramount importance and hence is a constructive discussion on occupational health risk factors. The replacement of human workers with robots on assembly nests, especially in SMEs, eliminates the exposure of workers to hazard, but is focused on a reduction in employment rather than in significant improvements to the workplace. The paper analyzes and discusses European safety regulations contained in the European directives and applicable EN standards. Appropriate safety programs of diverse welding processes and materials to be implemented by designers and suppliers of robotic welding stations and lines, as well as by the users thereof, will be indicated.

scholarly journals Effects of sleep on a high-heat capacity mattress on sleep stages, EEG power spectra, cardiac interbeat intervals and body temperatures in healthy middle-aged men‡

SLEEP ◽  
2019 ◽  
Vol 43 (5) ◽  
Author(s):  
Sebastian Herberger ◽  
Kurt Kräuchi ◽  
Martin Glos ◽  
Katharina Lederer ◽  
Lisa Assmus ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heat Capacity ◽  
Body Temperature ◽  
Wave Energy ◽  
Sleep Stage ◽  
High Heat ◽  
Body Temperatures ◽  
High Heat Capacity ◽  
Eeg Power ◽  
Core Body

Abstract Study Objectives This study deals with the question whether a slow (non-disturbing) reduction of core body temperature (CBT) during sleep increases sleep stage N3 and EEG slow wave energy (SWE) and leads to a slowing of heart rate in humans. Participants Thirty-two healthy male subjects with a mean ± SD age 46 ± 4 years and body mass index 25.2 ± 1.8 kg/m2. Methods A high-heat capacity mattress (HM) was used to lower body temperatures in sleep and was compared to a conventional low-heat capacity mattress (LM) in a double-blinded fashion. Polysomnography was performed accompanied by measurements of skin-, core body- and mattress surface-temperatures, and heart rate. EEG power spectral analyses were carried out using Fast Fourier Transform. Interbeat intervals were derived from the electrocardiogram. Results The HM led to a larger decline in CBT, mediated through higher heat conduction from the core via the proximal back skin onto the mattress together with reduced heart rate. These effects occurred together with a significant increase in sleep stage N3 and standardized slow wave energy (sSWE, 0.791–4.297 Hz) accumulated in NREM sleep. In the 2nd half of the night sSWE increase was significantly correlated with body temperature changes, for example with CBT decline in the same phase. Conclusions A HM subtly decreases CBT, leading to an increased amount of sleep stage N3 and of sSWE, as well as a slowing of heart rate.

scholarly journals CFD-Guided Development of Test Rigs for Studying Erosion and Large-Particle Damage of Thermal Barrier Coatings

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Maria A. Kuczmarski ◽  
Robert A. Miller ◽  
Dongming Zhu
Keyword(s):  
Thermal Barrier Coatings ◽  
Large Particle ◽  
Turbine Blades ◽  
High Heat ◽  
Heat Fluxes ◽  
Materials Testing ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Particle Damage ◽  
Computational Fluid Dynamics Cfd

Burner rigs are routinely used to qualify materials for gas turbine applications. The most useful rig tests are those that can replicate, often in an accelerated manner, the degradation that materials experience in the engine. Computational fluid dynamics (CFD) can be used to accelerate the successful development and continuous improvement of combustion burner rigs for meaningful materials testing. Rig development is typically an iterative process of making incremental modifications to improve the rig performance for testing requirements. Application of CFD allows many of these iterations to be done computationally before hardware is built or modified, reducing overall testing costs and time, and it can provide an improved understanding of how these rigs operate. This paper describes the use of CFD to develop burner test rigs for studying erosion and large-particle damage of thermal barrier coatings (TBCs) used to protect turbine blades from high heat fluxes in combustion engines. The steps used in this study—determining the questions that need to be answered regarding the test rig performance, developing and validating the model, and using it to predict rig performance—can be applied to the efficient development of other test rigs.

Non-destructive inspection of drilled holes in reinforced honeycomb sandwich panels using active thermography

2012 ◽  
Vol 55 (6) ◽  
pp. 491-498 ◽  
Author(s):  
R. Usamentiaga ◽  
P. Venegas ◽  
J. Guerediaga ◽  
L. Vega ◽  
I. López
Keyword(s):  
Sandwich Panels ◽  
Active Thermography ◽  
Honeycomb Sandwich ◽  
Non Destructive
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