29/03/2024
New Zealand field-scale fire experiments to test convective heat transfer in wildland firesWildfire physics has traditionally been studied through intensive modelling that requires numerous assumptions of combustion and heat transfer (Sullivan 2009) adapted from established structure-fire engineering relations. Renewed emphasis in experimental research has caused rethinking of some of the most basic concepts in wildland fuel particle ignition and flame spread. New findings from la...
29/03/2024
Rate dependency and ply thickness influence on transverse cracking evolution in cross-ply laminatesF. Coussa, J. Berthe, M. Ragonet.
In this study, the rate dependency of transverse cracking evolution in cross-ply laminates is investigated for several 90° plies thicknesses. The crack detection methodology is based on a recently proposed protocol relying on the use of infrared thermography. A new analysis methodology is proposed to make it more robust and to directly link the spatial...
29/03/2024
Using Longwave Infrared Hyperspectral Imaging for a Quantitative Atmospheric Tracer Monitoring in Outdoor EnvironmentsEitan Hirsch, Eyal Agassi, Alon Manor.
Quantitative real-time retrieval of concentration-lengths (CL) through gaseous plumes is an important tool for environmental monitoring, enabling remote monitoring of emissions from industrial facilities and risk assessment
in scenarios of toxic gas releases. The adoption of LWIR (Long Wave Infra-Red) hyperspectral imaging as a leading techniqu...
29/03/2024
Status and Developments in Geological Remote SensingR.D. Hewson et al.
Recent improvements and availability of optical to infrared to thermal satellite and airborne sensors opens up the opportunity for advancing surface mineralogy and geological mapping. Such mapping may include the identification of alteration zones for exploration activities or monitoring ore quality and inventory within open cuts. Remote sensing technology is also on...
29/03/2024
Thermomechanical Behavior of Steels in Tension Studied with Synchronized Full-Field Deformation and Temperature MeasurementsG.C. Soares, N.I. Vázquez-Fernández, M. Hokka
Despite tensile testing being commonly used for investigating the mechanical behavior of materials, the occurrence of heterogeneous strain and increasing temperature at high strain rates make the experiment much more complex. This work presents a method integrating synchronous full-field stereo Digital Image Correlation (DIC) and Infrared T...
29/03/2024
Ground-Based Remote Sensing of CH4 and N2O Fluxes from a Wastewater Treatment Plant and Nearby Biogas Production with Discoveries of Unexpected SourcesM. Gålfalk, S.N. Påledal, R. Sehlén, D. Bastviken.
This study is an attempt to assess CH4 and N2O emissions from all the treatment steps of a wastewater treatment plant (WWTP) in Sweden, serving 145 000 persons, and an adjacent biogas production facility. We have used novel mid-IR ground-based remote sensing with a hyperspectral camera to visualize and quantify the emissions on 21 days...
29/03/2024
Active Thermography for Panel Paintings Inspection: A Comparative Study of Midwave and Long-Wave Infrared Spectral AnalysisActive thermography was used as a multispectral non-destructive approach for characterisation of multi-layered panel paintings and analysis of their defects caused by aging and environmental effects. Two oil compositions painted on canvas, provided by C2RMF in the Louvre museum (Centre de Recherche et de Restauration des Musées de France) were under inspection. Active Thermography was demons...
29/03/2024
Detection of Gaseous Plumes in Airborne Hyperspectral ImageryThe thermal hyperspectral sensor Hyper-Cam was mounted on a light aircraft and measured continuous releases of several atmospheric tracers from a height of 2 km. A unique detection algorithm that eliminates the need for clear background estimation was operated over the acquired data with excellent detection results. The data-cubes were acquired in a “target mode”, which is a unique method of...
29/03/2024
Background Radiance Estimation for Gas Plume Quantification for Airborne Hyperspectral Thermal ImagingHyperspectral imaging in the long-wave infrared (LWIR) is a mean that is proving its worth in the characterization of gaseous effluent. Indeed the spectral and spatial resolution of acquisition instruments is steadily decreasing, making the gases characterization increasingly easy in the LWIR domain. The majority of literature algorithms exploit the plume contribution to the radiance corresp...
29/03/2024
Radiometry – The basicsWhat is radiometry? The etymology of radiometry links to “radiation” and “measurement”. More precisely, radiometry is the science studying the transport of energy through radiation.
The present document aims at presenting a summary of the principal laws of radiometry involved in the understanding of the world surrounding us, as seen through light-sensitive instruments! Among these are ...
29/03/2024
How to Interpret Images From Infrared CamerasA field campaign. A laboratory testbed. A volcano. Different applications of infrared cameras, but the very same modus operandi. Turn the camera on, point it toward the scene, and get images on the screen. It looks so simple! And the image is even calibrated in real temperature units. Great!
Real life conditions are unfortunately a bit more complex. Accurate interpretation of the infra...
28/03/2024
Direct Imaging of Shale Gas Leaks Using Passive Thermal Infrared Hyperspectral ImagingThere are many types of natural gas fields including shale formations that are common especially in the St-Lawrence Valley (Canada). Since methane (CH4), the major component of shale gas, is odorless, colorless and highly flammable, in addition to being a greenhouse gas, methane emanations and/or leaks are important to consider for both safety and environmental reasons.
Telops recently...
28/03/2024
High-Speed Infrared Imaging of a Split-Hopkinson Pressure Bar ExperimentIn order to illustrate this concept, high-speed infrared imaging was carried out at 13 000 frames per second during a split-Hopkinson pressure bar experiment on a polymer sample at the Structural Impact Laboratory (SIMLab) of the Norwegian University of Science and Technology. The results illustrate how high-speed infrared imaging can provide detailed information about the thermal properties...
28/03/2024
Volcanic Eruption Observations from an Elevated Point of Stromboli Using Thermal Infrared Hyperspectral ImagingThe Stromboli volcano is well known for its periodic eruptions of small magnitude containing various proportions of ash, lava and gases. Imaging was carried out at a relatively high spectral and spatial resolution before and during eruptions from the North-East crater. Both sulfur dioxide (SO2) and silicon tetrafluoride (SiF4) could be successfully identified within the volcano’s plume from ...
28/03/2024
High-Speed Infrared Imaging of Metal Parts Fabrication by Additive ManufacturingAdditive manufacturing, also known as 3D printing, is considered by many to be the biggest industrial revolution since the Internet. This method allows rapid fabrication of metal pieces with various compositions, shapes and sizes. However, the extremely high thermal gradients involved in this fabrication process can induce stress and deformation in the materials. In an effort to better under...