Magma fragmentation by rapid decompression

Nature ◽  
1996 ◽  
Vol 380 (6570) ◽  
pp. 146-148 ◽  
Author(s):  
Mikhail Alidibirov ◽  
Donald B. Dingwell
Keyword(s):  
Magma Fragmentation ◽  
Rapid Decompression

scholarly journals The products of primary magma fragmentation finally revealed by pumice agglomerates

Geology ◽  
2021 ◽  
Author(s):  
Thomas Giachetti ◽  
Kathleen R. Trafton ◽  
Joshua Wiejaczka ◽  
James E. Gardner ◽  
James M. Watkins ◽  
...  
Keyword(s):  
Potential Energy ◽  
Size Distributions ◽  
Secondary Fragmentation ◽  
Entire Process ◽  
Magma Fragmentation ◽  
Primary Products ◽  
Primary Fragmentation ◽  
Rapid Decompression ◽  
Original Size ◽  
Pumice Aggregates

Following rapid decompression in the conduit of a volcano, magma breaks into ash- to block-sized fragments, powering explosive sub-Plinian and Plinian eruptions that may generate destructive pyroclastic falls and flows. It is thus crucial to assess how magma breaks up into fragments. This task is difficult, however, because of the subterranean nature of the entire process and because the original size of pristine fragments is modified by secondary fragmentation and expansion. New textural observations of sub-Plinian and Plinian pumice lapilli reveal that some primary products of magma fragmentation survive by sintering together within seconds of magma break-up. Their size distributions reflect the energetics of fragmentation, consistent with products of rapid decompression experiments. Pumice aggregates thus offer a unique window into the previously inaccessible primary fragmentation process and could be used to determine the potential energy of fragmentation.

Lung Volumes, Pulmonary Ventilation, and Hypoxia Following Rapid Decompression to 60,000 ft (18,288 m)

2013 ◽  
Vol 84 (6) ◽  
pp. 551-559
Author(s):  
Desmond M. Connolly ◽  
Timothy J. D’Oyly ◽  
Amanda S. McGown ◽  
Vivienne M. Lee
Keyword(s):  
Pulmonary Ventilation ◽  
Lung Volumes ◽  
Rapid Decompression

Oxygen Poisoning in a Hyperbaric Environment

1970 ◽  
Vol 56 (1) ◽  
pp. 39-47
Author(s):  
J. Murray Young
Keyword(s):  
Partial Pressure ◽  
Sea Water ◽  
Signs And Symptoms ◽  
Pressure Chamber ◽  
Partial Pressure Of Oxygen ◽  
Oxygen Exposure ◽  
Rapid Decompression ◽  
Hyperbaric Environment ◽  
Biochemical Mechanisms ◽  
Oxygen Poisoning

AbstractThe biochemical mechanisms of oxygen poisoning are discussed together with the signs and symptoms produced clinically. Investigation of 35 subjects performing work (mean 02 consumption 1.4 l./min) for 40 minutes in a pressure chamber at simulated depths of 20 to 47 feet of sea water showed that this degree of exercise markedly reduced the oxygen exposure tolerance of the subjects. This investigation also showed that rapid decompression of subjects breathing oxygen can produce an exacerbation of existing symptoms and these results are discussed.It is stressed that any breathing mixture containing a partial pressure of oxygen in excess of 150 torr constitutes an environment which is hyperbaric with respect to oxygen and caution is advised in the administration of oxygen to any patient.

Hearing Aids Performance in Hypobaric Environments

2021 ◽  
Vol 92 (9) ◽  
pp. 738-743
Author(s):  
Marco Lucertini ◽  
Filippo Sanjust ◽  
Roberto Manca ◽  
Luigi Cerini ◽  
Lorenzo Lucertini ◽  
...  
Keyword(s):  
High Altitude ◽  
Hearing Aids ◽  
Ambient Air ◽  
Recording System ◽  
Simulated Altitude ◽  
Acoustic Transducers ◽  
Before And After ◽  
Rapid Decompression ◽  
Pressure Changes ◽  
First Session

OBJECTIVE: High altitudes imply exposure to a decreased ambient air pressure. Such a situation may also alter the performance of acoustic transducers using vibrating diaphragms due to air rarefaction. This study aimed at analyzing the performance at high altitude of hearing aids (HAs) where mechano-electric and electro-mechanic transducers are used. METHODS: A hypobaric chamber was used to perform two separated experimental sessions. In the first one two commercial models of HAs were exposed to a simulated altitude of 25,000 ft (7620 m) and to a subsequent rapid decompression profile, with a rapid climb (< 3 s) from 8000 (2438 m) to 25,000 ft. The second session separately analyzed the performance of microphone and receiver at an altitude of 9000 and 15,000 ft (2743 and 4572 m). Before and after the first session, the HAs were tested with an electronic ear while a dedicated recording system was used in the second session. RESULTS: No HA damage or dysfunction was detected during the first session. In the second one, the microphone showed a mild decrease of its output, while the receiver exhibited a much higher reduction of its output. CONCLUSION: Our findings highlight the safe use of HAs even under extreme environmental pressure changes. For altitudes exceeding 10,000 ft (3048 m), a recalibration of the HAs output via a dedicated program may be suggested. Lucertini M, Sanjust F, Manca R, Cerini L, Lucertini L, Sisto R. Hearing aids performance in hypobaric environments. Aerosp Med Hum Perform. 2021; 92(9):738743.

Loss of cabin pressure and rapid decompression

2019 ◽  
pp. 77-82
Author(s):  
Nicholas Green ◽  
Steven Gaydos ◽  
Hutchison Ewan ◽  
Edward Nicol
Keyword(s):  
Rapid Decompression

Transient Hyperemia Immediately after Rapid Decompression of Chronic Subdural Hematoma

Neurosurgery ◽  
1999 ◽  
Vol 45 (3) ◽  
pp. 484-489 ◽  
Author(s):  
Kuniaki Ogasawara ◽  
Keiji Koshu ◽  
Takashi Yoshimoto ◽  
Akira Ogawa
Keyword(s):  
Subdural Hematoma ◽  
Chronic Subdural Hematoma ◽  
Rapid Decompression

scholarly journals A Rare Complication of Chronic Subdural Hematoma Evacuation: Brain Stem Hemorrhage: A Case Report

2018 ◽  
Vol 32 (3) ◽  
pp. 462-465 ◽  
Author(s):  
Ghassen Gader ◽  
Mouna Rkhami ◽  
Maher Ben Salem ◽  
Mohamed Badri ◽  
Kamel Bahri ◽  
...  
Keyword(s):  
Brain Stem ◽  
Subdural Hematoma ◽  
Rare Complication ◽  
Chronic Subdural Hematoma ◽  
The Elderly ◽  
Burr Hole ◽  
Sudden Increase ◽  
Vascular Disruption ◽  
Rapid Decompression ◽  
Surgical Modality

Abstract Chronic subdural hematoma (CSDH), which commonly affects the elderly, is one of the most frequent, but also benign neurosurgical pathologies. Burr hole drainage is the standard surgical modality for evacuation of a CSDH. This technique is known to be safe, with low morbidity and mortality rates. However, postoperative complications have occasionally been reported. We report the case of a 70-year-old man who presented a fatal brain stem hemorrhage after burr-hole drainage for unilateral chronic subdural hematoma. Asymmetrical and rapid decompression were thought to be leading to vascular disruption or sudden increase in cerebral blood flow, was probably responsible for the secondary brain stem bleeding. Therefore, a slow rate of evacuation of chronic subdural hematomas, as well as rigorous postoperative reanimation, are recommended in order to prevent serious complications.

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