Discussion: “Conical Acrylic Windows Under Long-Term Hydrostatic Pressure of 10,000 psi” (Stachiw, J. D., 1972, ASME J. Eng. Ind., 94, pp. 1053–1059)

1972 ◽  
Vol 94 (4) ◽  
pp. 1059-1059
Author(s):  
J. L. Akterson
Keyword(s):  
Hydrostatic Pressure

A Deep-Ocean Mass Spectrometer to Monitor Hydrocarbon Seeps and Pipelines

2005 ◽  
Author(s):  
Gary M. McMurtry ◽  
John C. Wiltshire ◽  
Arnaud Bossuyt
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
Mass Spectrometer ◽  
Deep Ocean ◽  
Rechargeable Batteries ◽  
Vacuum System ◽  
Power Cable ◽  
Electron Multiplier ◽  
Trace Contaminant

New developments in instrumentation for ocean environmental engineering are allowing unprecedented levels of trace contaminant measurement in the deep ocean. With funding from the U.S. National Science Foundation (NSF), our engineering design team constructed a new mass spectrometer-based in situ analysis system for work in the deep ocean environment over prolonged deployment periods. Our design goals were a depth capability of up to 4,000 m water depth (400 bars hydrostatic pressure) and autonomous operation for periods of up to six months to a year, depending upon the type of external battery system used or other deployment circumstances, e.g., availability of a power cable or fuel cell power source. We chose a membrane introduction mass spectrometry (MIMS) sampling approach, which allows for dissolved gases and volatile organics introduction into the mass spectrometer vacuum system. The MIMS approach and the hydrophobic, silicon-coated membrane chosen both draw upon our previous experience with this technology in the deep ocean. The membrane has been tested to 400 bars in a series of long-term hydrostatic pressure tests, which extend the 200-bar working depth rating of this membrane by a factor of 2. Long-term deployment capability of the moderately powered, approximately 100 W system, was accomplished by power management of the embedded computer system and custom electronics with Windows-based and custom software now fully-developed and bench tested. The entire system fits within a 6.5-inch outside diameter pressure housing that is approximately five feet long. It consists of a 1 to 200 amu range quadrupole mass spectrometer equipped with Faraday and electron multiplier detectors, compact turbo-molecular and backing diaphragm vacuum pumps, internal rechargeable batteries, and internal waste vacuum chamber. Sample routing past the MIMS is accomplished by computer-controlled solenoid valves. We designed the pressure housings of both 6AL4V and type 2 titanium alloys that are rated to working depths of >4,000 m and are essentially corrosion proof over long-term deployments. We designed and integrated a fail-safe valving system for both rapid response to high-pressure MIMS failure and a pressure-switch circuit and high-pressure solenoid valve to detect and protect against slow leaks of the MIMS. To route sample waters to the MIMS-based instrument, we also designed and built a rugged plastic plenum that couples to the face of the sampler head, the latter of which consists of the MIMS inlet and a full-ocean rated thermister temperature probe with an operational range from −5 to 50°C. These instrumentation innovations will be described in the paper.

Integration of Hydrostatic Pressure Information by Identified Interneurones in the Crab Carcinus maenas (L.); Long-Term Recordings

2001 ◽  
Vol 54 (1) ◽  
pp. 71-79 ◽  
Author(s):  
P. J. Fraser ◽  
A. G. Macdonald ◽  
S. F. Cruickshank ◽  
M. P. Schraner
Keyword(s):  
Hydrostatic Pressure ◽  
Gas Phase ◽  
Progress Monitoring ◽  
Carcinus Maenas ◽  
Shore Crab ◽  
Pressure Sensitive ◽  
Animal Navigation ◽  
Tidal Changes ◽  
Pressure Changes

This paper was first presented at the RIN97 Conference held in Oxford under the auspices of the Animal Navigation Special Interest Group, April 1997.Migrating species may utilise hydrostatic pressure. In the aquatic environment, hydrostatic pressure changes much more rapidly than in air. In shallow water, tidal changes will impose larger percentage changes on organisms than those experienced in deep water. Small changes in pressure often cause locomotion (barokinesis) accompanied by orientation to light or gravity, often partially compensating for the equivalent depth change. Until recently, identification of hydrostatic pressure receptors without a gas phase has proved elusive, but it is now known that thread hair receptors in the statocyst of the shore crab Carcinus maenas respond to small changes in hydrostatic pressure. Using a tide machine, the responses of thread hairs to sinusoidally changing pressure cycles have been examined, and this paper reports progress monitoring this receptor and making long-term recordings from hydrostatic pressure sensitive pathways in the crab's nervous system.

Conical Acrylic Windows Under Long-Term Hydrostatic Pressure of 5000 psi

1972 ◽  
Vol 94 (3) ◽  
pp. 843-848
Author(s):  
J. D. Stachiw
Keyword(s):  
Hydrostatic Pressure ◽  
Diameter Ratio ◽  
Axial Displacement ◽  
Included Angle ◽  
Temperature Range ◽  
Hydrostatic Loading ◽  
General Service

Conical acrylic windows with included angle 30 deg ≤ α ≤ 150 deg and thickness to minor diameter ratio of 0.375 ≤ t/D ≤ 1.00 have been subjected to 5,000 psi sustained hydrostatic loading of 1,000 hr duration in 65–75 deg F temperature range while the axial displacement of the windows through the flange has been monitored. The magnitude of axial displacement was found to be a function of α, t/D, temperature and duration of loading. Only windows with t/D ratios ≥1.000, 0.625, 0.500, 0.500, and 0.500 for 30, 60, 90, 120, and 150 deg conical angles, respectively, were found to be free of cracks. It is recommended that only windows with included angle α ≥ 60 deg be utilized for general service (long-term and cyclic) under 5,000 psi maximum hydrostatic pressure. The corresponding t/D ratios recommended for general service are 0.750 for α = 60 deg, and 0.625 for α ≥ 90 deg.

Conical Acrylic Windows Under Long Term Hydrostatic Pressure of 20,000 Psi

1970 ◽  
Vol 92 (1) ◽  
pp. 237-256
Author(s):  
J. D. Stachiw
Keyword(s):  
Hydrostatic Pressure ◽  
Room Temperature ◽  
Cone Angle ◽  
Diameter Ratio ◽  
Model Scale ◽  
Hydrostatic Loading ◽  
Pressure Application ◽  
Temperature Test

Conical acrylic windows with cone angles 30 deg ≤ α ≤ 150 deg have been subjected to sustained hydrostatic pressure of 20,000 psi for up to 1,000 hr duration. The thickness to minor diameter ratio (t/D) of the more than 200 windows varied from 0.750 to 2.000. Model scale windows served as the bulk of test specimens, and the majority of the tests were conducted at room temperature. Test findings indicate that only windows with t/D > 1 and cone angle α ≥ 60 deg will not fail in less than 1,000 hr of sustained hydrostatic loading although considerable cracking will take place. For optically acceptable service of 1000 hr duration under 20,000 psi hydrostatic pressure, the windows must have t/D ≥ 2 and a cone angle α ≥ 90 deg. The axial displacements of such windows after 1000 hr of hydrostatic loading at 20,000 psi, are approximately 0.1 times their minor diameter, with approximately 50 percent of this displacement taking place during the first hour of pressure application.

Conical Acrylic Windows Under Long-Term Hydrostatic Pressure of 10,000 psi

1972 ◽  
Vol 94 (4) ◽  
pp. 1053-1059 ◽  
Author(s):  
J. D. Stachiw
Keyword(s):  
Hydrostatic Pressure ◽  
Deep Ocean ◽  
Diameter Ratio ◽  
Conical Cavity ◽  
Ambient Temperatures ◽  
Hydrostatic Loading ◽  
Pressure Application ◽  
Sustained Loading ◽  
General Service

Over 150 conical frustum acrylic plastic windows were subjected to 10,000 psi hydrostatic loading of up to 1000-hr duration in deep ocean simulators maintained at 65–75 deg F ambient temperature. Axial displacements of the windows under hydrostatic loading through the conical cavity in the flange were recorded and plotted as a function of time, thickness to minor diameter ratio (t/D), and included conical angle α. Data indicate that only windows with α ≥ 90 deg and t/D ≥ 0.75 are satisfactory for sustained long-term hydrostatic loading of 1000-hr duration at 10,000 psi in ambient temperatures ≤80 deg F. For general service, which includes also cyclic pressurizations to 10,000 psi, an included angle α ≥ 90 deg and t/D ratio of ≥ 1.0 are recommended. The axial displacement of windows recommended for 10,000 psi service is approximately 0.04D after 1000 hr of sustained loading. Approximately 75 percent of this displacement takes place during the first hour of pressure application.

scholarly journals Elevated hydrostatic pressure activates sodium/hydrogen exchanger-1 in rat optic nerve head astrocytes

2009 ◽  
Vol 297 (1) ◽  
pp. C111-C120 ◽  
Author(s):  
Amritlal Mandal ◽  
Mohammad Shahidullah ◽  
Nicholas A. Delamere ◽  
Marcos A. Terán
Keyword(s):  
Optic Nerve ◽  
Hydrostatic Pressure ◽  
Protein Expression ◽  
Optic Nerve Head ◽  
Elevated Hydrostatic Pressure ◽  
Cultured Astrocytes ◽  
Sodium Hydrogen Exchanger ◽  
Recovery From Acidification ◽  
Nhe1 Activity

Optic nerve head astrocytes become abnormal in eyes that have elevated intraocular pressure, and cultured astrocytes display altered protein expression after being subjected for ≥1 days to elevated hydrostatic pressure. Here we show that 2-h elevated hydrostatic pressure (15 or 30 mmHg) causes phosphorylation of ERK1/2, ribosomal S6 protein kinase (p90RSK), and Na/H exchanger (NHE)1 in cultured rat optic nerve head astrocytes as judged by Western blot analysis. The MEK/ERK inhibitor U0126 abolished phosphorylation of NHE1 and p90RSK as well as ERK1/2. To examine NHE1 activity, cytoplasmic pH (pHi) was measured with BCECF and, in some experiments, cells were acidified by 5-min exposure to 20 mM ammonium chloride. Although baseline pHi was unaltered, the rate of pHi recovery from acidification was fourfold higher in pressure-treated astrocytes. In the presence of either U0126 or dimethylamiloride (DMA), an NHE inhibitor, hydrostatic pressure did not change the rate of pHi recovery. The findings are consistent with NHE1 activation due to phosphorylation of ERK1/2, p90RSK, and NHE1 that occurs in response to hydrostatic pressure. These responses may precede long-term changes of protein expression known to occur in pressure-stressed astrocytes.

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