scholarly journals On the cooling of a 360� video camera to observe fire dynamics in situ

2019 ◽  
Author(s):  
Jiann C Yang
Keyword(s):  
Video Camera ◽  
Fire Dynamics

scholarly journals Development of a Field Deployable Firebrand Flux and Condition Measurement System

2020 ◽  
Author(s):  
Simone Zen ◽  
Jan C. Thomas ◽  
Eric V. Mueller ◽  
Bhisham Dhurandher ◽  
Michael Gallagher ◽  
...  
Keyword(s):  
Imaging Techniques ◽  
Time History ◽  
Infrared Camera ◽  
Thermal Conditions ◽  
Particle Characterization ◽  
Fire Dynamics ◽  
Rate Of Spread ◽  
New Instrument ◽  
History Of

AbstractA new instrument to quantify firebrand dynamics during fires with particular focus on those associated with the Wildland-Urban Interface (WUI) has been developed. During WUI fires, firebrands can ignite spot fires, which can rapidly increase the rate of spread (ROS) of the fire, provide a mechanism by which the fire can pass over firebreaks and are the leading cause of structure ignitions. Despite this key role in driving wildfire dynamics and hazards, difficulties in collecting firebrands in the field and preserving their physical condition (e.g. dimensions and temperature) have limited the development of knowledge of firebrand dynamics. In this work we present a new, field-deployable diagnostic tool, an emberometer, designed to provide measurement of firebrand fluxes and information on both the geometry and the thermal conditions of firebrands immediately before deposition by combining a visual and infrared camera. A series of laboratory experiments were conducted to calibrate and validate the developed imaging techniques. The emberometer was then deployed in the field to explore firebrand fluxes and particle conditions for a range of fire intensities in natural pine forest environments. In addition to firebrand particle characterization, field observations with the emberometer enabled detailed time history of deposition (i.e. firebrand flux) relative to concurrent in situ fire behaviour observations. We highlight that deposition was characterised by intense, short duration “showers” that can be reasonably associated to spikes in the average fire line intensity. The results presented illustrate the potential use of an emberometer in studying firebrand and spot fire dynamics.

In Situ Observation Method for Quantitative Evaluation of Solidification Phenomena and Solidification Cracks during Welding

2014 ◽  
Vol 782 ◽  
pp. 3-7
Author(s):  
Kenji Shinozaki ◽  
Motomichi Yamamoto ◽  
Kohta Kadoi ◽  
Peng Wen
Keyword(s):  
High Speed ◽  
Video Camera ◽  
Solidification Cracking ◽  
In Situ Observation ◽  
High Speed Video Camera ◽  
Varestraint Test ◽  
Solidification Cracks ◽  
Observation Method ◽  
Solidification Crack

Solidification cracking during welding is very serious problem for practical use. Therefore, there are so many reports concerning solidification cracking. Normally, solidification cracking susceptibility of material is quantitatively evaluated using Trans-Varestraint test. On the other hand, local solidification cracking strain was tried to measure precisely using in-situ observation method, called MISO method about 30 years ago. Recently, digital high-speed video camera develops very fast and its image quality is very high. Therefore, we have started to observe solidification crack using in site observation method. In this paper, the local critical strain of a solidification crack was measured and the high temperature ductility curves of weld metals having different dilution ratios and different grain sizes to evaluate quantitatively the effects of dilution ratio and grain size on solidification cracking susceptibility by using an improved in situ observation method.

Evaluation of Non-Uniform Deformation of Multi-Layered Ceramic Sheets with Printed Electrodes during Compression

2011 ◽  
Vol 418-420 ◽  
pp. 1647-1653
Author(s):  
Fumio Naruse ◽  
Naoya Tada
Keyword(s):  
Deformation Behavior ◽  
Recent Trend ◽  
Video Camera ◽  
Transverse Displacement ◽  
Compression Tests ◽  
Electronic Components ◽  
Uniform Deformation ◽  
Digital Video Camera ◽  
Layered Ceramic

With the recent trend of down-sizing and more efficient use of electric power in electric appliances, there is a growing need of smaller electronic components, such as multi-layered ceramic capacitors (MLCCs). However, it was found that the non-uniform deformation occurred in MLCC block during the pressing process and it hinders the miniaturization of MLCCs. In this study, compression tests of multi-layered ceramic sheets with printed electrodes were carried out and the deformation behavior was observed in situ and recorded by digital video camera. The change in area fraction and transverse displacement were evaluated and the deformation mechanism was inferred from the results.

Time and Space Evolution of Emitting Carbon Nanoparticles – Correlation with the Formation of Fullerenes and Carbon Nanotubes –

2000 ◽  
Vol 633 ◽  
Author(s):  
Shinzo Suzuki ◽  
Rahul Sen ◽  
Hirofumi Yamaguchi ◽  
Toshinobu Ishigaki ◽  
Yohsuke Ohtsuka ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanoparticles ◽  
High Speed ◽  
Video Camera ◽  
Laser Vaporization ◽  
High Speed Video Camera ◽  
Higher Fullerenes ◽  
Sublimation Method ◽  
Graphite Rod

AbstractThe temporal and spatial evolution of emitting carbon nanoparticles were investigated using a laser furnace apparatus combined with a high-speed video camera. An apparent increase in the blackbody emission intensity at Δt > 400 [.proportional]sec after laser vaporization of a graphite rod was clearly recognized. Also, it was found that this increasing tendency corresponds well to that of the fullerene yield, where fullerene species was obtained as sublimed carbon material using in situ sublimation method. These findings suggest that a certain exothermic process related to the formation of C60, other higher fullerenes, and carbon nanotubes should occur at Δt > 400 νsec inside the furnace.

In situ Temperature Measurement During Spray Forming of A2-tool Steel and Axisymmetric Two-dimensional Analysis

2000 ◽  
Vol 15 (8) ◽  
pp. 1669-1678 ◽  
Author(s):  
B. C. Moon ◽  
Z. H. Lee ◽  
D. R. White ◽  
E. J. Lavernia
Keyword(s):  
Experimental Data ◽  
Temperature Measurement ◽  
Tool Steel ◽  
Video Camera ◽  
Spray Forming ◽  
Cooling Curve ◽  
Two Dimensional ◽  
Forming Process ◽  
Infrared Video

An in situ temperature measurement was performed during spraying of A2-tool steel, and the results were used to verify an axisymmetric two-dimensional computer simulation program, which was developed for the prediction of shape and temperature variation in a spray-forming process. A thin thermocouple was placed inside of the chamber in advance and brought to the surface of the deposit during spraying. The temperature was then recorded. The surface temperature of the deposit was also measured by an infrared video camera. The emissivity of the surface of A2-tool steel during spraying was determined to be 0.23 through comparison of the temperatures measured by the thermocouple with the ones measured by the infrared video camera. The heat transfer coefficient at the top surface was estimated by comparing the calculated results with the experimental data. The cooling curve predicted on the basis of the numerical simulation showed good agreement with the experimental data.

Dynamic Ice Forces Analysis of Conical Structure Based on Direct Measurement

2010 ◽  
Author(s):  
Ning Xu ◽  
Qianjin Yue
Keyword(s):  
Direct Measurement ◽  
Failure Process ◽  
Video Camera ◽  
Ice Load ◽  
Conical Structure ◽  
Force Variation ◽  
Ice Force ◽  
Bending Failure ◽  
Ice Forces

The dynamic ice force is produced by failure process during ice interaction with structure. The best way for describing and modeling this process is using directly measured ice force on full scale structure in situ. In this paper, the ice force variation and corresponded failure process of ice sheet were recorded by ice load panel and video camera. It is demonstrated that when ice acting on upward narrow cone and in bending failure and well clearing by side of the cone. The form of ice force history looks like impulse signal.

scholarly journals In-Situ Observation of Adhesion Behavior During Ultrasonic Al Ribbon Bonding

2019 ◽  
Vol 9 (9) ◽  
pp. 1835 ◽  
Author(s):  
Yasuo Takahashi ◽  
Kazumasa Takashima ◽  
Kouta Misawa ◽  
Yusuke Takaoka
Keyword(s):  
Ultrasonic Vibration ◽  
High Speed ◽  
Peel Test ◽  
Video Camera ◽  
In Situ Observation ◽  
Direction Parallel ◽  
Central Belt ◽  
Silica Substrate ◽  
Adhesion Behavior

In-situ observation was performed on a transparent silica substrate during ultrasonic Al ribbon bonding, using a high-speed video camera with differing frame rates, 104 fps and 103 fps, to clarify the adhesion behavior. The bonding process was observed as follows. Initially, friction slip occurred, producing multiple island streaks in the direction parallel to the ultrasonic vibration. The island streaks were formed as a scratch, due to surface waviness of the Al ribbon. Momentarily, a belt-shaped bond zone was formed at the center, normally due to the ultrasonic vibration. The island streaks could be clearly observed at 104 fps. However, the central belt zone was unclear and appeared translucent at 104 fps; although it was clear when observed at 103 fps. The island streaks were unclear at 103 fps. The positional relation of the island streaks and the central belt zone was confirmed from in-situ observation results of a twist and peel test of Al ribbon bonded to silica substrate. The central belt zone was between the island streaks and the silica substrate.

scholarly journals A Balloonborne Particle Size, Imaging, and Velocity Probe for in Situ Microphysical Measurements

2015 ◽  
Vol 32 (9) ◽  
pp. 1562-1580 ◽  
Author(s):  
Sean M. Waugh ◽  
Conrad L. Ziegler ◽  
Donald R. MacGorman ◽  
Sherman E. Fredrickson ◽  
Doug W. Kennedy ◽  
...  
Keyword(s):  
Particle Size ◽  
Video Camera ◽  
Cloud Microphysics ◽  
High Definition ◽  
Spatiotemporal Resolution ◽  
Winter Storms ◽  
Convective Clouds ◽  
Chemistry Experiment ◽  
Initial Results

AbstractA balloonborne instrument known as the Particle Size, Image, and Velocity (PASIV) probe has been developed at the National Severe Storms Laboratory to provide in situ microphysical measurements in storms. These observations represent a critical need of microphysics observations for use in lightning studies, cloud microphysics simulations, and dual-polarization radar validation. The instrument weighs approximately 2.72 kg and consists of a high-definition (HD) video camera, a camera viewing chamber, and a modified Particle Size and Velocity (Parsivel) laser disdrometer mounted above the camera viewing chamber. Precipitation particles fall through the Parsivel sampling area and then into the camera viewing chamber, effectively allowing both devices to sample the same particles. The data are collected on board for analysis after retrieval. Taken together, these two instruments are capable of providing a vertical profile of the size, shape, velocity, orientation, and composition of particles along the balloon path within severe weather.The PASIV probe has been deployed across several types of weather environments, including thunderstorms, supercells, and winter storms. Initial results from two cases in the Deep Convective Clouds and Chemistry Experiment are shown that demonstrate the ability of the instrument to obtain high-spatiotemporal- resolution observations of the particle size distributions within convection.

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