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.

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.

Mechanical strength characterization and modeling of hydroxyapatite/tricalcium phosphate biocomposite using the diametral-compression test

2021 ◽  
Vol 93 (3) ◽  
pp. 30403
Author(s):  
Mohammed Es-Saddik ◽  
Said Laasri ◽  
Abdelaziz Laghzizil ◽  
Jean-Michel Nunzi ◽  
Mohammed Taha ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Tricalcium Phosphate ◽  
Sintering Temperature ◽  
Rupture Strength ◽  
Mechanical Resistance ◽  
The Finite Element Method ◽  
Maximum Value ◽  
Strength Characterization ◽  
Powder Manufacturing ◽  
Diametral Compression Test

This study reports the enhanced mechanical resistance of the composite bioceramics of hydroxyapatite (HAP) and tricalcium phosphate (β-TCP) used as bone substitute. HAP/β-TCP mixture was prepared by wet mixing of powders and characterized. Effects of powder manufacturing and sintering temperature on the densification, microstructure and mechanical properties of the composite were studied. The rupture strength (σr) was calculated using the Brazilian test. At 1250 °C, the relative density and mechanical strength of the HAP/β-TCP ceramics reached the maximum value of 89% and 43 MPa, respectively. Experimental results were modeled by the finite element method to determine the stress distribution in the compacted disc.

Intrinsic Mode Entropy Analysis of Tube-Wall Pressure Fluctuation Signals in the Kenics Static Mixer

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Hui-Bo Meng ◽  
Zhi-Qiang Liu ◽  
Yan-Fang Yu ◽  
Qiang Xiong ◽  
Jian-Hua Wu
Keyword(s):  
Pressure Fluctuation ◽  
Tube Wall ◽  
Sample Entropy ◽  
Wall Pressure ◽  
High Frequency Component ◽  
Static Mixer ◽  
Flow Rates ◽  
Multi Scale ◽  
Wall Pressure Fluctuation ◽  
Macro Scale

The multi-scale nonlinear hydrodynamics in Kenics Static Mixer (KSM) with 100 mm in diameter and 2 in aspect ratio was investigated in this work. The time series of tube-wall pressure fluctuation signals were measured at different flow rates ranged of 100~600 L•h-1 and at different axial positions in the range of 420~580 mm away from the cross-section of mixer inlet. It is difficult for composite signals to make an effective analysis by Sample Entropy (SampEn) based on a single scale. The complexity of tube-wall pressure fluctuation signals in a Kenics static mixer was investigated using Intrinsic Mode Entropy (IMEn) based on Sample Entropy algorithm and Empirical Mode Decomposition (EMD) method. Data sampling length and tolerance are optimized based on intrinsic mode entropy. Results of multi-scale analysis of pressure fluctuations indicated that the Sample entropy reaches maximum in the first scale and progressively decreases according to increase of the decomposed order. It is clear that the movement of high frequency component of the pressure signal is the most complicated and is rich in randomness. With the decomposition scales increasing, the complexity of signal decreases and approaches periodic motion eventually. The intrinsic mode entropy of the tube wall pressure signals in KSM has similar development tendencies in different flow rates. Besides, as the flow rates increased, the macro-scale vortexes play a more and more important role and guide the system to develop toward the stable state.

Incorporation of Petroleum Coke into Red Ceramic

2010 ◽  
Vol 660-661 ◽  
pp. 681-685
Author(s):  
Carlos Maurício Fontes Vieira ◽  
Lussandra Arêdes Freitas ◽  
Rubén Jesus Sánchez Rodríguez ◽  
Sérgio Neves Monteiro
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
Water Absorption ◽  
Optical Microscopy ◽  
Petroleum Coke ◽  
Rupture Strength ◽  
Physical And Mechanical Properties ◽  
Refining Plant

This work has as its objective to evaluate the effect in the physical and mechanical properties of a red ceramic by the incorporation of petroleum coke from a refining plant. The characterization of the coke was done by optical microscopy and DTA/TG. Compositions were prepared with 0, 1, 2 and 4 wt.% of petroleum coke incorporated into a kaolinitic clayey body. Rectangular specimens were formed by extrusion before firing at 950°C. The determined physical and mechanical properties were: flexural rupture strength and water absorption. The microstructure of the fired ceramics was evaluated by SEM. The results showed that the incorporation of up to 4 wt.% of petroleum coke is not deleterious to the water absorption and mechanical strength of the clayey ceramic fired at 950oC.

Influence of the Granite Waste into a Clayey Ceramic Body for Rustic Wall Tiles

2012 ◽  
Vol 727-728 ◽  
pp. 1057-1062 ◽  
Author(s):  
Monica Castoldi Borlini Gadioli ◽  
Mariane Costalonga de Aguiar ◽  
Abiliane de Andrade Pazeto ◽  
Sérgio Neves Monteiro ◽  
Carlos Maurício Fontes Vieira
Keyword(s):  
Mechanical Strength ◽  
Water Absorption ◽  
Raw Materials ◽  
Rupture Strength ◽  
Ceramic Body ◽  
Linear Shrinkage ◽  
Ceramic Production ◽  
Ornamental Stones ◽  
Error Bar ◽  
Press Molding

This work has as its objective to evaluate the influence of a granite waste into a clayey ceramic body for obtaining of rustic wall tiles. As raw materials, a clayey ceramic body for red ceramic production and a granite waste, resulting from ornamental stones cutting with the multi-wire technology were used. Compositions using 0, 10, 20 and 30% of waste incorporated into ceramic body were prepared. Specimens were fabricated by uniaxial press-molding at 20 MPa and sintered at 1050°C. The following properties were determined: linear shrinkage, water absorption and flexural rupture strength. In general, within the error bar, there was no influence of the waste in the values of water absorption of the clayey ceramic body. The results showed that all investigated formulations used in this work for the production of rustic wall tiles attend the standards for water absorption and mechanical strength.

scholarly journals Evaluation and validation of technical procedure for foundry coke mechanical strength testing

2020 ◽  
Author(s):  
Bartosz Mertas ◽  
Aleksander Sobolewski ◽  
Grzegorz Rozycki
Keyword(s):  
Sample Preparation ◽  
Mechanical Strength ◽  
Physical Properties ◽  
International Standards ◽  
Strength Testing ◽  
Strength Index ◽  
Technical Procedure ◽  
Foundry Coke ◽  
Simplified Procedure ◽  
Testing And Evaluation

Abstract Foundry coke is a special type of coke with lumps size usually bigger than 100 mm. Therefore it is difficult to asses its physical properties representatively for whole lot. There exist international standards for coke sampling and testing strength index (usually Micum test). Nevertheless companies dealing with foundry coke notified problems with methodology of sampling and sample preparation for the test. Manual sampling according to ISO 18283 is very labour extensive and with connection with literally proceeding with ISO 566 gives non-representative results for foundry coke +100 mm. For this reason on the basis of these standards there was evaluated procedure for coke sampling and testing strength indexes which is more practical for plant routine use and gives more reliable results in comparison to international standard. This article presents results of work aimed at checking usability of ISO standards provisions for foundry coke testing and evaluation and validation of simplified procedure.

scholarly journals Environmental and diagenetic controls on the morphology and calcification of the Ediacaran metazoan Cloudina

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amy Shore ◽  
Rachel Wood
Keyword(s):  
Mechanical Strength ◽  
Tube Wall ◽  
High Energy ◽  
Early Diagenesis ◽  
Low Energy ◽  
Post Mortem ◽  
Relative Thickness ◽  
Controlled Morphology ◽  
Globally Distributed

AbstractCloudina is a globally distributed Ediacaran metazoan, with a tubular, funnel-in-funnel form built of thin laminae (ca. 1–10 μm). To what degree local environmental controlled morphology, and whether early diagenesis controlled the degree of calcification of Cloudina, is debated. Here we test these hypotheses by considering assemblages from four, coeval localities from the Upper Omkyk Member, Nama Group, Namibia, from inner ramp to mid-ramp reef across the Zaris Subbasin. We show that sinuosity of the Cloudina tube is variable between sites, as is the relative thickness of the tube wall, suggesting these features were environmentally controlled. Walls are thickest in high-energy reef settings, and thinnest in the low-energy, inner ramp. While local diagenesis controls preservation, all diagenetic expressions are consistent with the presence of weakly calcified, organic-rich laminae, and lamina thicknesses are broadly constant. Finally, internal ‘cements’ within Cloudina are found in all sites, and pre-date skeletal breakage, transport, as well as syn-sedimentary botryoidal cement precipitation. Best preservation shows these to be formed by fine, pseudomorphed aragonitic acicular crystals. Sr concentrations and Mg/Ca show no statistically significant differences between internal Cloudina cements and botryoidal cements, but we infer all internal cements to have precipitated when Cloudina was still in-situ and added considerable mechanical strength, but may have formed post-mortem or in abandoned parts of the skeleton.

Pressure-driven fusion of amorphous particles into integrated monoliths

Science ◽  
2021 ◽  
Vol 372 (6549) ◽  
pp. 1466-1470
Author(s):  
Zhao Mu ◽  
Kangren Kong ◽  
Kai Jiang ◽  
Hongliang Dong ◽  
Xurong Xu ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Mechanical Strength ◽  
Applied Pressure ◽  
Bound Water ◽  
External Pressure ◽  
Temperature Sensitive ◽  
Mass Transportation ◽  
Amorphous Calcium Carbonate ◽  
Amorphous Particles ◽  
Biological Organisms

Biological organisms can use amorphous precursors to produce inorganic skeletons with continuous structures through complete particle fusion. Synthesizing monoliths is much more difficult because sintering techniques can destroy continuity and limit mechanical strength. We manufactured inorganic monoliths of amorphous calcium carbonate by the fusion of particles while regulating structurally bound water and external pressure. Our monoliths are transparent, owing to their structural continuity, with a mechanical strength approaching that of single-crystal calcite. Dynamic water channels within the amorphous bulk are synergistically controlled by water content and applied pressure and promote mass transportation for particle fusion. Our strategy provides an alternative to traditional sintering methods that should be attractive for constructing monoliths of temperature-sensitive biominerals and biomaterials.

To Slip or Not to Slip: Water Flows in Hydrophilic and Hydrophobic Microchannels

2002 ◽  
Author(s):  
Chang-Hwan Choi ◽  
K. Johan A. Westin ◽  
Kenneth S. Breuer
Keyword(s):  
Shear Rate ◽  
Slip Length ◽  
Surface Condition ◽  
Applied Pressure ◽  
Good Control ◽  
Channel Height ◽  
Self Assembled Monolayer ◽  
Flow Rates ◽  
Hydrophilic Surfaces ◽  
Slip Effects

The slip effects of water flow in hydrophilic and hydrophobic microchannels of 1 and 2 μm depth are examined experimentally. Fabrication processes for silicon/Pyrex microchannels were chosen to ensure good control of the channel height and to obtain atomically smooth surfaces. Hydrophilic surfaces were prepared with an RCA-1 cleaning, while hydrophobic surfaces were created by coating the channel surface with the self-assembled monolayer of octadecyltrichorosilane (OTS). The flow rates of pure DI water at various applied pressure differences for each surface condition were measured using a high precision flow metering system and it was observed that the flow rates in hydrophobic channels is larger than in the same hydrophilic channel. The increase of the flow rate can be explained by assuming a slip velocity at the wall. The slip effects become more pronounced as the channel height decreases and the wall shear rate increases. The slip length was found to vary as approximately the square root of the shear rate and had values of approximately 40 nm in the hydrophobic channels and 15 nm in the hydrophilic channels at a shear rate of 105 s−1.

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