The effects of high pressure on foil strain gages

1964 ◽  
Vol 4 (2) ◽  
pp. 25-36 ◽  
Author(s):  
R. V. Milligan
Keyword(s):  
High Pressure ◽  
Strain Gages

Geotechnical Instrumentation: Monitoring Longitudinal Stress of a High Pressure Pipeline During Longwall Mining Operations — A Case Study in West Virginia

2016 ◽  
Author(s):  
Martin P. Derby ◽  
Mark D. Saunders ◽  
Benjamin Zand
Keyword(s):  
High Pressure ◽  
West Virginia ◽  
Stress Analysis ◽  
Longwall Mining ◽  
Monitoring Program ◽  
Solar Array ◽  
Strain Gages ◽  
Mining Operations ◽  
Strain Monitoring ◽  
Implementation Program

Longwall mining operations could compromise the integrity of high pressure pipelines by way of surface subsidence and soil strains. Prior to implementing field programs for monitoring subsidence, a preliminary mitigation/stress analysis study should be designed to determine the possible effects of the longwall mining operations on the pipeline(s). If the stress analysis indicates possible high stresses beyond the allowable limits of a pipeline, then a mitigation plan should be developed and implemented. Regardless of the anticipated stress level in a pipeline, a strain monitoring program is usually recommended. The purpose of this paper is to discuss the design of a pipeline strain monitoring program, which includes the installation of strain gages at critical locations along two adjacent pipelines. The study area includes a 12 inch diameter steel pipeline (for natural gas transport) and a 12 inch HDPE pipeline for water transport. The study area is located in a mountainous region of West Virginia. Prior to the field program, a laboratory pilot study was performed with strain gages on a test section of HDPE pipe to determine the best mounting procedures. The field implementation program included the installation of strain gages on the gas and water pipelines. Multiplexers, data loggers, a solar array and a satellite modem for 24/7 data transfer were installed, and monitored throughout the study. During the field implementation program several meteorological and geologic events occurred which caused some design changes in the field program.

Static Testing High-Pressure Piping Components

1960 ◽  
Vol 82 (1) ◽  
pp. 15-22 ◽  
Author(s):  
T. G. Moore ◽  
E. J. Opersteny
Keyword(s):  
High Pressure ◽  
Safety Factor ◽  
Tube Wall ◽  
Strain Gages ◽  
Working Pressure ◽  
Exterior Surface ◽  
Static Testing ◽  
Wire Strain ◽  
Pressure Tubing ◽  
Piping Systems

A method for testing high-pressure piping systems for service in the 20,000 to 40,000-psi range is described. Tubing systems were pressure tested and their behavior followed by means of resistance-wire strain gages mounted on the exterior surface. A method is described for graphically determining the pressure at which a tube wall becomes fully plastic. The allowable working pressure of a tube is determined by applying a safety factor to this pressure. Tubing bends and fittings, including metal gaskets, flanges, and tees, are evaluated by comparing their behavior under pressure with that of the tube with which they are to be used.

High-pressure freezing of cells in suspension for low-voltage scanning electron microscopy (LVSEM)

1991 ◽  
Vol 49 ◽  
pp. 64-65
Author(s):  
Marek Malecki ◽  
James Pawley ◽  
Hans Ris
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Low Voltage ◽  
Culture Media ◽  
Cell Structure ◽  
Freeze Substitution ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Cell Culture Media ◽  
Voltage Scanning

The ultrastructure of cells suspended in physiological fluids or cell culture media can only be studied if the living processes are stopped while the cells remain in suspension. Attachment of living cells to carrier surfaces to facilitate further processing for electron microscopy produces a rapid reorganization of cell structure eradicating most traces of the structures present when the cells were in suspension. The structure of cells in suspension can be immobilized by either chemical fixation or, much faster, by rapid freezing (cryo-immobilization). The fixation speed is particularly important in studies of cell surface reorganization over time. High pressure freezing provides conditions where specimens up to 500μm thick can be frozen in milliseconds without ice crystal damage. This volume is sufficient for cells to remain in suspension until frozen. However, special procedures are needed to assure that the unattached cells are not lost during subsequent processing for LVSEM or HVEM using freeze-substitution or freeze drying. We recently developed such a procedure.

Prolonged Fixation Studies For Spaceflight

1973 ◽  
Vol 31 ◽  
pp. 332-333
Author(s):  
Robert Corbett ◽  
Delbert E. Philpott ◽  
Sam Black
Keyword(s):  
High Pressure ◽  
Living Systems ◽  
Prolonged Storage ◽  
Time Intervals ◽  
Early Signs ◽  
Large Numbers

Observation of subtle or early signs of change in spaceflight induced alterations on living systems require precise methods of sampling. In-flight analysis would be preferable but constraints of time, equipment, personnel and cost dictate the necessity for prolonged storage before retrieval. Because of this, various tissues have been stored in fixatives and combinations of fixatives and observed at various time intervals. High pressure and the effect of buffer alone have also been tried.Of the various tissues embedded, muscle, cartilage and liver, liver has been the most extensively studied because it contains large numbers of organelles common to all tissues (Fig. 1).

Cryosectioning plant roots prepared by high-pressure freezing

1987 ◽  
Vol 45 ◽  
pp. 662-663
Author(s):  
R.E. Crang ◽  
M. Mueller ◽  
K. Zierold
Keyword(s):  
High Pressure ◽  
Cell Walls ◽  
Plant Tissues ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Vitreous State ◽  
Radial Depth ◽  
Irregular Topography ◽  
Considerable Depth ◽  
Conventional Freezing

Obtaining frozen-hydrated sections of plant tissues for electron microscopy and microanalysis has been considered difficult, if not impossible, due primarily to the considerable depth of effective freezing in the tissues which would be required. The greatest depth of vitreous freezing is generally considered to be only 15-20 μm in animal specimens. Plant cells are often much larger in diameter and, if several cells are required to be intact, ice crystal damage can be expected to be so severe as to prevent successful cryoultramicrotomy. The very nature of cell walls, intercellular air spaces, irregular topography, and large vacuoles often make it impractical to use immersion, metal-mirror, or jet freezing techniques for botanical material.However, it has been proposed that high-pressure freezing (HPF) may offer an alternative to the more conventional freezing techniques, inasmuch as non-cryoprotected specimens may be frozen in a vitreous, or near-vitreous state, to a radial depth of at least 0.5 mm.

High-pressure freezing and freeze substitution of plant tissue

1992 ◽  
Vol 50 (1) ◽  
pp. 748-749
Author(s):  
William P. Sharp ◽  
Robert W. Roberson
Keyword(s):  
High Pressure ◽  
Cell Structure ◽  
Leaf Tissue ◽  
Freeze Substitution ◽  
Crystal Formation ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Cell Components ◽  
Cold Metal ◽  
Brome Grass

The aim of ultrastructural investigation is to analyze cell architecture and relate a functional role(s) to cell components. It is known that aqueous chemical fixation requires seconds to minutes to penetrate and stabilize cell structure which may result in structural artifacts. The use of ultralow temperatures to fix and prepare specimens, however, leads to a much improved preservation of the cell’s living state. A critical limitation of conventional cryofixation methods (i.e., propane-jet freezing, cold-metal slamming, plunge-freezing) is that only a 10 to 40 μm thick surface layer of cells can be frozen without distorting ice crystal formation. This problem can be allayed by freezing samples under about 2100 bar of hydrostatic pressure which suppresses the formation of ice nuclei and their rate of growth. Thus, 0.6 mm thick samples with a total volume of 1 mm3 can be frozen without ice crystal damage. The purpose of this study is to describe the cellular details and identify potential artifacts in root tissue of barley (Hordeum vulgari L.) and leaf tissue of brome grass (Bromus mollis L.) fixed and prepared by high-pressure freezing (HPF) and freeze substitution (FS) techniques.

Microstructural Study of Diamond Deformed Under High Pressure and Temperature

1985 ◽  
Vol 43 ◽  
pp. 230-231
Author(s):  
E. F. Koch
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Lattice Structure ◽  
Diamond Particle ◽  
Polycrystalline Diamond ◽  
Sintering Process ◽  
Ion Milling ◽  
Sintered Compact ◽  
Transmission Electron ◽  
High Pressure Sintering

Because of the extremely rigid lattice structure of diamond, generating new dislocations or moving existing dislocations in diamond by applying mechanical stress at ambient temperature is very difficult. Analysis of portions of diamonds deformed under bending stress at elevated temperature has shown that diamond deforms plastically under suitable conditions and that its primary slip systems are on the ﹛111﹜ planes. Plastic deformation in diamond is more commonly observed during the high temperature - high pressure sintering process used to make diamond compacts. The pressure and temperature conditions in the sintering presses are sufficiently high that many diamond grains in the sintered compact show deformed microtructures.In this report commercially available polycrystalline diamond discs for rock cutting applications were analyzed to study the deformation substructures in the diamond grains using transmission electron microscopy. An individual diamond particle can be plastically deformed in a high pressure apparatus at high temperature, but it is nearly impossible to prepare such a particle for TEM observation, since any medium in which the diamond is mounted wears away faster than the diamond during ion milling and the diamond is lost.

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