Implosion of living Nautilus under increased pressure

Paleobiology ◽  
1980 ◽  
Vol 6 (1) ◽  
pp. 44-47 ◽  
Author(s):  
Yasumitsu Kanie ◽  
Yoshio Fukuda ◽  
Hideaki Nakayama ◽  
Kunihiro Seki ◽  
Mutsuo Hattori
Keyword(s):  
Hydrostatic Pressure ◽  
Hyperbaric Chamber ◽  
Depth Limit ◽  
Mature Specimen ◽  
Nautilus Pompilius ◽  
Increased Pressure

In a hyperbaric chamber, a living mature specimen of Nautilus pompilius withstood a hydrostatic pressure of 8.05 MPa (80.5 kg/cm2) equivalent to 785 m deep in the sea. Thereafter it was killed instantly by implosion of the shell. Before implosion, the animal reacted physiologically to increasing pressure. Therefore, the depth of 785 m can be assigned the depth limit of N. pompilius. The result bears on critical interpretations on the paleoecology and paleobiology of extinct nautiloids and ammonoids with similar shells.

Hematologic response of fish to changes in gas or hydrostatic pressure

1980 ◽  
Vol 239 (1) ◽  
pp. R161-R167 ◽  
Author(s):  
E. Casillas ◽  
L. S. Smith ◽  
J. J. Woodward ◽  
B. G. D'Aoust
Keyword(s):  
Hydrostatic Pressure ◽  
Plasma Proteins ◽  
Fibrinolytic Activity ◽  
Coagulation System ◽  
Related Phenomenon ◽  
Protein Levels ◽  
Diffuse Intravascular Coagulation ◽  
Rapid Decompression ◽  
Increased Pressure ◽  
Increased Susceptibility

Hematologic changes were studied in fingering salmon after rapid decompression from combined or independent exposure to gas and hydrostatic pressure. After decompression, fingerling salmon saturated with excess gas under pressure (10.1-40.6 m of seawater) suffered a decrease in thrombocyte counts and fibrinogen, prolonged prothrombin (PT) times, and increased fibrinolytic activity, plasma proteins, and erythrocyte counts in proportion to severity of the dive. After decompression, fingerling salmon exposed to increased pressure experienced an increase in thrombocyte counts and available fibrinogen, shortened PT times, increased erythrocyte counts, and decreased plasma protein levels. It appeared that pressure causes activation of the blood coagulation system of fish. This activation may predispose the fish to increased susceptibility to bubble-induced diffuse intravascular coagulation after rapid decompression. Furthermore, hemoconcentration after decompression may be a pressure-related phenomenon and not a response to bubble-induced anoxia.

Observations on the Effects of Changes of Hydrostatic Pressure on the Behaviour of Some Marine Animals

1964 ◽  
Vol 44 (1) ◽  
pp. 163-175 ◽  
Author(s):  
A. L. Rice
Keyword(s):  
Hydrostatic Pressure ◽  
Experimental Method ◽  
Relative Importance ◽  
Marine Plankton ◽  
Marine Animals ◽  
The Hours ◽  
Gravity Receptors ◽  
Pressure Changes ◽  
Increased Activity ◽  
Increased Pressure

An apparatus and experimental method for the investigation of the effects of changes of pressure on the behaviour of marine animals is described.In 43 of a total of 53 species examined in this apparatus definite responses to abrupt pressure changes of 1000 millibars or less have been observed, increased pressure generally causing increased activity and movement upwards or towards the light, and decreased pressure causing decreased activity and movement downwards or away from the light. The relative importance of light and gravity in the orientation of these movements is generally correlated with the degree of development of the light and gravity receptors in the species concerned.The possible significance of these pressure responses in nature is discussed and it is suggested that pressure may be an important factor affecting the distribution of marine plankton, particularly during the hours of darkness.

Effect of High Hydrostatic Pressure on the Permeability of Elastomers to Water

1966 ◽  
Vol 39 (4) ◽  
pp. 1298-1307 ◽  
Author(s):  
Alexander Lebovits
Keyword(s):  
Hydrostatic Pressure ◽  
Thermodynamic Analysis ◽  
Atmospheric Pressure ◽  
High Hydrostatic Pressure ◽  
Polymeric Materials ◽  
Butyl Rubber ◽  
Pressurized Water ◽  
Simple Method ◽  
Increased Pressure

Abstract The permeability of butyl rubber to pressurized water was measured at 10,000 psi hydrostatic pressure using a relatively simple method which consisted of constructing pouches from rubber, filling these with desiccant and exposing them to pressurized water. At this high hydrostatic pressure the permeability was found to be smaller than at atmospheric pressure which suggests the suitability of butyl rubber for the construction of hydrophone boots used at great depths. Similar results found by other investigators for other polymeric materials are cited. A thermodynamic analysis of the process of permeation by activated diffusion was made and a mechanism was discussed which explains the decrease in permeability of butyl rubber to water with increased pressure.

scholarly journals BASIC MECHANISM OF HYPERBARIC OXYGEN IN INFECTIOUS DISEASE

2016 ◽  
Vol 2 (1) ◽  
pp. 49 ◽  
Author(s):  
Prihartini Widiyanti
Keyword(s):  
Infectious Disease ◽  
Wound Healing ◽  
Hyperbaric Oxygen ◽  
Hyperbaric Oxygen Therapy ◽  
Side Effect ◽  
Oxygen Therapy ◽  
Basic Mechanism ◽  
Cumulative Number ◽  
Hyperbaric Chamber ◽  
Increased Pressure

Hyperbaric oxygen therapy (HBOT) is the inhalation of 100 percent oxygen inside a hyperbaric chamber that is pressurized to greater than 1 atmosphere (atm). HBOT causes both mechanical and physiologic effects by inducing a state of increased pressure and hyperoxia. HBOT is typically administered at 1 to 3 atm. While the duration of an HBOT session is typically 90 to 120 minutes, the duration, frequency, and cumulative number of sessions have not been standardized. HBO has been use widely in treating gangrene diabetic, stroke, osteomyelitis and accelerating wound healing. The use of HBO in infectious disease is wide, so the mechanism of hyperbaric oxygen in infectious disease should be well-understand. This understanding could bring the proper and wise management of infectious disease and to prevent the side effect of each therapy.

Increased pressure of nitrogen-oxygen mixture and the temperature in animals

2015 ◽  
Vol 9 (4) ◽  
pp. 0-0 ◽  
Author(s):  
Вётош ◽  
A. Vetosh ◽  
Лучаков ◽  
Yu. Luchakov ◽  
Несмеянов ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
High Pressure ◽  
Oxygen Consumption ◽  
Mathematical Models ◽  
Oxygen Mixture ◽  
Neutral Zone ◽  
Hyperbaric Chamber ◽  
Gas Medium ◽  
Increased Pressure

The work is devoted to the study of thermoregulation of rats under high pressure in the respiratory- gas medium, both experimentally and in mathematical models. Experiments conducted on rats in a hyperbaric chamber, where the pressure of the gas medium was raised to 4,1 MPa. The pressure increase in the hyperbaric chamber up to 2,1 MPa leds to augmentation of oxygen consumption by 1.7 times and at a pressure of 4.1 MPa – to oxygen consumption by 2,3 times. Thermo-neutral zone in animals, on the contrary, is progressively decreased with increasing pressure in the hyperbaric chamber. Using a mathematical model, it has been shown that the augmentation of pressure in the hyperbaric chamber to 2,1 MPa leads to increase the heat transfer in 1,9 times. The augmentation of pressure in the hyperbaric chamber to 4,1 MPa increases the heat transfer from the organism body in the medium in 2,6 times.

The Microstructure of Diene Polymers. II. Polyisoprenes and Polybutadienes Prepared at High Pressures

1954 ◽  
Vol 27 (4) ◽  
pp. 958-961
Author(s):  
W. S. Richardson
Keyword(s):  
Free Radical ◽  
Hydrostatic Pressure ◽  
Chemical Reactions ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
High Pressures ◽  
Bulk Polymerization ◽  
Extensive Investigation ◽  
Very High ◽  
Increased Pressure

Abstract The rapid bulk polymerization of isoprene at room temperature under high hydrostatic pressure was apparently first observed by Bridgman and Conant. A more extensive investigation by Conant and Tongberg established the free radical nature of the polymerization (peroxide catalysis and hydroquinone inhibition). The latter workers also noted the solubility and elasticity of polymers made to moderate conversion and the insoluble crumbly nature (gelation) of the polymers made to very high conversion. In view of the well known effect of increased pressure in driving chemical reactions in the direction of the products of least specific volume, it is of interest to consider the possibility that diene polymers made at high pressures may be different in microstructure from polymers made at comparable temperatures but near atmospheric pressure.

Rupture strength and flow rate of Nautilus siphuncular tube

Paleobiology ◽  
1982 ◽  
Vol 8 (4) ◽  
pp. 408-425 ◽  
Author(s):  
John A. Chamberlain ◽  
William A. Moore
Keyword(s):  
Mechanical Strength ◽  
Tube Wall ◽  
Rupture Strength ◽  
Applied Pressure ◽  
Strength Index ◽  
Live Animal ◽  
Depth Limit ◽  
Flow Rates ◽  
Nautilus Pompilius ◽  
Index Ratio

The siphuncular tube is a key component of the buoyancy control and mechanical strength systems in both Nautilus and fossil cephalopods. We measured the rate of hydrostatically induced fluid flow across the tube wall and tube rupture strength of Nautilus pompilius at hydrostatic pressures in the range of 10–85 bars. We found that in fresh, undecayed tubes, rupture occurs at pressures of about 80–85 bars. This is equivalent to the strength of the shell proper and to the depth limit of the live animal. The siphuncular tube is neither markedly stronger, nor weaker, than the shell. Siphuncle rupture strength is constant in the last 20 chambers of the shell despite a strong decrease in the siphuncle strength index (ratio of tube thickness to radius). The notion that strength index gives an accurate indication of tube strength is therefore in error. This suggests that the geometry of the siphuncular tube can not be straightforwardly used as an index of living depth in fossil cephalopods. Rupture occurs at the siphuncle-septum contact. The junction of the tube to its mechanical supports is thus weaker than the tube itself. Measured flow rates are in the range of 1–20 ml/h/chamber. Flow rates increase linearly with applied pressure and in successively larger chambers as a result of size-related variation in surface area and thickness of the tube wall. Rates of osmotic pumping in live animals are up to three orders of magnitude lower than hydrostatically induced flow rates across the siphuncular tubes of empty shells. Pumping capacity of live animals is apparently limited by functional constraints of the osmotic pump rather than by the fluid conductance properties of the tube wall. Living depth in evolving cephalopod lineages may be limited ultimately by physiologic or chemical restrictions of the osmotic pumping mechanism rather than by mechanical strength of the shell or siphuncle.

scholarly journals The Circulatory Effects of Increased Hydrostatic Pressure Due to Immersion and Submersion

2021 ◽  
Vol 12 ◽  
Author(s):  
Robert P. Weenink ◽  
Thijs T. Wingelaar
Keyword(s):  
Blood Flow ◽  
Hydrostatic Pressure ◽  
Vertical Gradient ◽  
Body Part ◽  
The Body ◽  
Cardiovascular Collapse ◽  
Circulatory Effects ◽  
Main Effect ◽  
Cold Liquid ◽  
Increased Pressure

Increased hydrostatic pressure as experienced during immersion and submersion has effects on the circulation. The main effect is counteracting of gravity by buoyancy, which results in reduced extravasation of fluid. Immersion in a cold liquid leads to peripheral vasoconstriction, which centralizes the circulation. Additionally, a pressure difference usually exists between the lungs and the rest of the body, promoting pulmonary edema. However, hydrostatic pressure does not exert an external compressing force that counteracts extravasation, since the increased pressure is transmitted equally throughout all tissues immersed at the same level. Moreover, the vertical gradient of hydrostatic pressure down an immersed body part does not act as a resistance to blood flow. The occurrence of cardiovascular collapse when an immersed person is rescued from the water is not explained by removal of hydrostatic squeeze, but by sudden reinstitution of the effect of gravity in a cold and vasoplegic subject.

scholarly journals Comparative cephalopod shell strength and the role of septum morphology on stress distribution

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2434 ◽  
Author(s):  
Robert Lemanis ◽  
Stefan Zachow ◽  
René Hoffmann
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Hydrostatic Pressure ◽  
High Stress ◽  
Wall Stress ◽  
Empirical Models ◽  
Element Analysis ◽  
Nautilus Pompilius ◽  
Computed Tomographic ◽  
Controversial Topic

The evolution of complexly folded septa in ammonoids has long been a controversial topic. Explanations of the function of these folded septa can be divided into physiological and mechanical hypotheses with the mechanical functions tending to find widespread support. The complexity of the cephalopod shell has made it difficult to directly test the mechanical properties of these structures without oversimplification of the septal morphology or extraction of a small sub-domain. However, the power of modern finite element analysis now permits direct testing of mechanical hypothesis on complete, empirical models of the shells taken from computed tomographic data. Here we compare, for the first time using empirical models, the capability of the shells of extantNautilus pompilius,Spirula spirula, and the extinct ammoniteCadocerassp. to withstand hydrostatic pressure and point loads. Results show hydrostatic pressure imparts highest stress on the final septum with the rest of the shell showing minimal compression.S. spirulashows the lowest stress under hydrostatic pressure whileN. pompiliusshows the highest stress.Cadocerassp. shows the development of high stress along the attachment of the septal saddles with the shell wall. Stress due to point loads decreases when the point force is directed along the suture as opposed to the unsupported chamber wall.Cadocerassp. shows the greatest decrease in stress between the point loads compared to all other models. Greater amplitude of septal flutes corresponds with greater stress due to hydrostatic pressure; however, greater amplitude decreases the stress magnitude of point loads directed along the suture. In our models, sutural complexity does not predict greater resistance to hydrostatic pressure but it does seem to increase resistance to point loads, such as would be from predators. This result permits discussion of palaeoecological reconstructions on the basis of septal morphology. We further suggest that the ratio used to characterize septal morphology in the septal strength index and in calculations of tensile strength of nacre are likely insufficient. A better understanding of the material properties of cephalopod nacre may allow the estimation of maximum depth limits of shelled cephalopods through finite element analysis.

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