HUBBLE SPACE TELESCOPEIMAGING OF DECOUPLED DUST CLOUDS IN THE RAM PRESSURE STRIPPED VIRGO SPIRALS NGC 4402 AND NGC 4522

This paper first addresses the question: what is a dust explosion? Afterwards, some specific issues are briefly reviewed: materials that can give dust explosions, factors influencing ignitability and explosibility of dust clouds, the combustion of dust clouds in air, ignition sources that can initiate dust explosions, primary and secondary dust explosions, dust flash fires, explosions of “hybrid mixtures”, and detonation of dust clouds. Subsequently, measures for dust explosion prevention and mitigation are reviewed. The next section presents the case history of an industrial dust explosion catastrophe in China in 2014. In the final section, a brief review is given of some current research issues that are related to the prevention and mitigation of dust explosions. There is a constant need for further research and development in all the areas elucidated in the paper.

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Driving in the Dust: Challenges and Lessons Learned from Field Testing in Degraded Visual Environments

Proceedings of the Human Factors and Ergonomics Society Annual Meeting ◽

10.1177/1071181320641462 ◽

2020 ◽

Vol 64 (1) ◽

pp. 1916-1920

Author(s):

Kayla L. Riegner ◽

Kelly S. Steelman

Keyword(s):

Research Program ◽

Field Tests ◽

Field Testing ◽

Driving Performance ◽

Lessons Learned ◽

Current Paper ◽

Ground Vehicle ◽

Significant Safety ◽

Dust Clouds

Degraded visual environments (DVEs) pose significant safety and efficiency problems in military ground vehicle operations. As part of a larger research program, two field tests were conducted to evaluate driving aids while indirect driving in DVEs. The current paper presents the results of one of these field tests, and focuses on the challenges and lessons learned in designing a challenging test course and producing consistent dust clouds for assessing Soldier driving performance and workload in degraded visual environments.

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Morphometry as a probe of the evolution of jellyfish galaxies: evidence of broadening in the surface brightness profiles of ram-pressure stripping candidates in the multicluster system A901/A902

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3226 ◽

2020 ◽

Vol 500 (1) ◽

pp. 40-53

Author(s):

Fernanda Roman-Oliveira ◽

Ana L Chies-Santos ◽

Fabricio Ferrari ◽

Geferson Lucatelli ◽

Bruno Rodríguez Del Pino

Keyword(s):

Star Formation ◽

Surface Brightness ◽

Quantitative Measurement ◽

Star Formation Rate ◽

Hubble Space Telescope ◽

Formation Rate ◽

Structural Evolution ◽

Star Forming ◽

Irregular Structures ◽

Ram Pressure

ABSTRACT We explore the morphometric properties of a group of 73 ram-pressure stripping candidates in the A901/A902 multicluster system, at z∼ 0.165, to characterize the morphologies and structural evolution of jellyfish galaxies. By employing a quantitative measurement of morphometric indicators with the algorithm morfometryka on Hubble Space Telescope (F606W) images of the galaxies, we present a novel morphology-based method for determining trail vectors. We study the surface brightness profiles and curvature of the candidates and compare the results obtained with two analysis packages, morfometryka and iraf/ellipse on retrieving information of the irregular structures present in the galaxies. Our morphometric analysis shows that the ram-pressure stripping candidates have peculiar concave regions in their surface brightness profiles. Therefore, these profiles are less concentrated (lower Sérsic indices) than other star-forming galaxies that do not show morphological features of ram-pressure stripping. In combination with morphometric trail vectors, this feature could both help identify galaxies undergoing ram-pressure stripping and reveal spatial variations in the star formation rate.

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R Coronae Borealis Stars: Long-Term Photometric & Spectroscopic Studies

Highlights of Astronomy ◽

10.1017/s1539299600021298 ◽

1998 ◽

Vol 11 (1) ◽

pp. 379-379

Author(s):

P.L. Cottrell ◽

L. Skuljan ◽

P.M. Kilmartin ◽

C. Gilmore ◽

W.A. Lawson

Keyword(s):

Radial Velocity ◽

Spectroscopic Studies ◽

Photometric Data ◽

Decline Phase ◽

Dust Clouds ◽

Medium Resolution ◽

Formation And Evolution ◽

R Coronae Borealis Stars ◽

Insight Into

For more than a decade we have been able to acquire and analyse a significant amount of photometric data of the highly variable R Coronae Borealis (RCB) stars. This has made been possible by a photometric service observing programme instigated at the Observatory. These photometric data have been combined with less extensive spectroscopic coverage, particularly of the decline phase of these stars. These have been supplemented by observations obtained at Mount Stromlo and Siding Spring Observatories for a radial velocity study. Significantly more spectroscopic observations are now being acquired with the development of a new medium resolution spectrograph at Mount John University Observatory. In this poster we will present recent photometric and spectroscopic results for a number of the RCB stars in our sample. This observational and analysis work can be used to provide further insight into the nature of these stars, their likely progeny and progenitors and the processes that are involved in the formation and evolution of the obscuring dust clouds which cause the decline phase.

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Radial Flow Velocity Field for Predicting Upper-Bound Solutions for Plane Strain Extrusion

Journal of Basic Engineering ◽

10.1115/1.3605063 ◽

1968 ◽

Vol 90 (1) ◽

pp. 45-50

Author(s):

R. G. Fenton

Keyword(s):

Velocity Field ◽

Flow Field ◽

Flow Velocity ◽

Plane Strain ◽

Upper Bound ◽

Radial Flow ◽

Flow Velocity Field ◽

Wide Range ◽

Ram Pressure ◽

Considerable Range

The upper bound of the average ram pressure, based on an assumed radial flow velocity field, is derived for plane strain extrusion. Ram pressures are calculated for a complete range of reduction ratios and die angles, considering a wide range of frictional conditions. Results are compared with upper-bound ram pressures obtained by considering velocity fields other than the radial flow field, and it is shown that for a considerable range of reduction ratios and die angles, the radial flow field yields better upper bounds for the average ram pressure.

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