Dispersion of dense gas puffs released in the atmosphere at ground level

1981 ◽  
Vol 15 (4) ◽  
pp. 509-525 ◽  
Author(s):  
R.G. Picknett
Keyword(s):  
Ground Level ◽  
Dense Gas

scholarly journals CFD Analysis of Indoor Chlorine Gas Dispersion Storage: Temperatures, Wind Velocities and Ventilation Effects Studies

2016 ◽  
Vol 16 (1) ◽  
pp. 1
Author(s):  
M. Safakar ◽  
S. Syafiie ◽  
R. Yunus
Keyword(s):  
Ground Level ◽  
Dense Gas ◽  
Human Beings ◽  
Potential Health ◽  
Gas Dispersion ◽  
Indoor Space ◽  
Hazardous Chemical ◽  
Chlorine Gas ◽  
Different Temperatures ◽  
Wind Velocities

The Chemical products factories encounter inherent environmental risks in the process. The indoor release of hazardous chemical gases that are heavier than the air is nowadays a special subject for scrutiny because the dense clouds of the gas have a tendency to insist on the ground level or near the human breath level, causing fatal injuries or other potential health threats to human beings. In this study, a computational fluid dynamics (CFD) code FLUENT was employed in order to model the accidental indoor dispersion of a dense gas (chlorine) from a small undetected leak in an indoor industrial environment. Furthermore, the effects of different temperatures, wind velocities and ventilation on diffusion of chlorine are investigated in this paper. Results of the simulations represented that the chlorine gas dispersion would behave like the liquid and currents on the floor. It was also found that the chlorine concentration above the ground level increased slowly. Showing the effects of various temperatures and wind on spreading the dense gas will help to better identify the potential risks. In this research, the effects of the environmental situations with the release and spread of chlorine in the indoor space were meticulously investigated.

scholarly journals Hazards Generated by an LNG Road Tanker Leak: Field Investigation of Vapour Propagation under Class B Conditions of Atmospheric Stability

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8483
Author(s):  
Tomasz Węsierski ◽  
Robert Piec ◽  
Małgorzata Majder-Łopatka ◽  
Bernard Król ◽  
Wiktor Gawroński ◽  
...  
Keyword(s):  
Discharge Rate ◽  
Temperature Drop ◽  
Atmospheric Stability ◽  
Ground Level ◽  
Field Investigation ◽  
Dense Gas ◽  
Maximum Value ◽  
Propagation Axis ◽  
Class B ◽  
Gas Cloud

The publication presents the results of a field test of 2–4 min releases of 96% LNG from a road tanker designed to carry the gas. The release was performed at a pressure of 5.9–6.1 atm at a discharge rate of 1.67–1.78 kg/s from a height of 0.75 m under class B conditions of atmospheric stability. Comparison of the obtained experimental results of the maximum concentrations and the simulation carried out with the EFFECS (11.2.0) software showed that the Gaussian gas model better describes the gas cloud propagation at most control points at this release intensity than the dense gas model. The dense gas model gave only slightly better results along the cloud propagation axis at close distances, not exceeding 25/30 m at ground level. It is shown that concentrations between 71% and 110% LEL are observed at the cloud visibility limit. The maximum value of the temperature drop, in the release axis, at a distance of 4 m amounts to ∆Tmax = 93.3 °C. This indicates that the cloud of the released LNG is almost entirely in the vapour state already in the short distance from the point of release, due to the turbulent outflow of the pressurised gas.

Effects of Vibration on the Preparation of Ultrathin Sections

1973 ◽  
Vol 31 ◽  
pp. 358-359
Author(s):  
Joseph M. Blum ◽  
Edward P. Gargiulo ◽  
J. R. Sawers
Keyword(s):  
Cutting Speed ◽  
Ground Level ◽  
Environmental Vibration ◽  
Block Face ◽  
Ultrathin Sections ◽  
Embedding Medium ◽  
Thickness Variations ◽  
Building Walls ◽  
Cutting Direction ◽  
Diamond Knife

It is now well-known that chatter (Figure 1) is caused by vibration between the microtome arm and the diamond knife. It is usually observed as a cyclical variation in “optical” density of an electron micrograph due to sample thickness variations perpendicular to the cutting direction. This vibration might be induced by using too large a block face, too large a clearance angle, excessive cutting speed, non-uniform embedding medium or microtome vibration. Another prominent cause is environmental vibration caused by inadequate building construction. Microtomes should be installed on firm, solid floors. The best floors are thick, ground-level concrete pads poured over a sand bed and isolated from the building walls. Even when these precautions are followed, we recommend an additional isolation pad placed on the top of a sturdy table.

A global perspective of ground level, 'ambient' carbon dioxide for assessing the response of plants to atmospheric CO2

2001 ◽  
Vol 7 (7) ◽  
pp. 789-796 ◽  
Author(s):  
L. H. Ziska ◽  
O. Ghannoum ◽  
J. T. Baker ◽  
J. Conroy ◽  
J. A. Bunce ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Ground Level ◽  
Global Perspective ◽  
Atmospheric Co2

The Sovereign States of Vietnam, 1945–1955

2016 ◽  
Vol 11 (3-4) ◽  
pp. 103-139 ◽  
Author(s):  
Brett Reilly
Keyword(s):  
Ground Level ◽  
Indochina War

This paper revisits the “bricolage” State of Vietnam and the fractured system of sovereignty that characterized its halting practice of sovereignty at the ground level during the First Indochina War. In addition, it examines how the French Union’s concept of shared external sovereignty became discredited by the end of the war.

Bones at ground level

2015 ◽  
Author(s):  
Elaine Walker
Keyword(s):  
Ground Level

The study of ground-level ozone over Kyiv and its impact on public health

2011 ◽  
Vol 17 (1) ◽  
pp. 52-59
Author(s):  
A.V. Shavrina ◽  
◽  
I.A. Mikulskaya ◽  
S.I. Kiforenko ◽  
V.A. Sheminova ◽  
...  
Keyword(s):  
Public Health ◽  
Ground Level ◽  
Ground Level Ozone
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