Volume Changes in the Stretching of Vulcanized Natural Rubber

1951 ◽  
Vol 24 (4) ◽  
pp. 767-772 ◽  
Author(s):  
Geoffrey Gee ◽  
Jan Stern ◽  
L. R. G. Treloar
Keyword(s):  
Tensile Stress ◽  
Natural Rubber ◽  
Volume Change ◽  
Isotropic Material ◽  
Volume Changes ◽  
Change Mechanism ◽  
Hydrostatic Component

Abstract Measurements are presented of the volume changes accompanying small (≯100%) elongations of vulcanized natural rubber completely free from undissolved particles. The small expansions found agree with those calculated from the known compressibility of rubber and the hydrostatic component of the stretching force. It is pointed out that this volume change mechanism applies generally to any isotropic material, and does not contribute significantly (in rubber) to the tensile stress.

Volume Change Associated to Carbon Partitioning from Martensite to Austenite

2012 ◽  
Vol 706-709 ◽  
pp. 2290-2295 ◽  
Author(s):  
M. J. Santofimia ◽  
Lie Zhao ◽  
Jilt Sietsma
Keyword(s):  
Volume Change ◽  
Chemical Potential ◽  
Theoretical Models ◽  
Carbon Partitioning ◽  
Volume Changes ◽  
Measured Volume

Annealing of martensite/austenite microstructures leads to the partitioning of carbon from martensite to austenite until the chemical potential of carbon equilibrates in both phases. This work calculates the volume change associated with this phenomenon using theoretical models for the carbon partitioning from martensite to austenite. Calculations are compared with experimentally determined volume changes. This comparison reveals that in the case of steels with higher contents of austenite-stabilizing elements, reported volume changes are satisfactory predicted assuming a low mobilily martensite/austenite interface. In the case of a steel with lower additions of austenite-stabilizing elements, experimentally measured expansions are considerably larger than predicted ones. The large measured volume expansions probably reflect the decomposition of the austenite.

A New Micro-Respirometer with Automatic Setting and Recording Apparatus

1950 ◽  
Vol 27 (3) ◽  
pp. 334-349
Author(s):  
PETER TUFT
Keyword(s):  
Volume Change ◽  
Constant Pressure ◽  
Volume Changes ◽  
Recording Apparatus

A new micro-respirometer is described, capable of measuring rates of volume change from 5 µl./hr. down to 0.01 µl./hr. to the nearest 0.001 µl. It is a constant-pressure nul-reading instrument and the actual volumes of gas absorbed or evolved are obtained from readings of the instrument by a simple multiplication. A device is described which sets the instrument automatically and records the volume changes at regular intervals.

Pressure response to quick volume changes in tetanized isolated ferret hearts

1989 ◽  
Vol 257 (1) ◽  
pp. H38-H46 ◽  
Author(s):  
K. B. Campbell ◽  
A. R. Rahimi ◽  
D. L. Bell ◽  
R. D. Kirkpatrick ◽  
J. A. Ringo
Keyword(s):  
Cardiac Muscle ◽  
Muscle Fiber ◽  
Volume Change ◽  
Initial Pressure ◽  
Recovery Phase ◽  
Left Ventricular ◽  
Fast Recovery ◽  
Volume Changes ◽  
Slow Recovery ◽  
Length Changes

Observed pressure responses to quick volume changes in the isolated tetanized heart of ferrets were compared with previously reported tension responses to quick length changes in isolated cardiac muscle. Hearts were isolated from ferrets, perfused with ryanodine solution, and stimulated rapidly (50 ms between stimulations) to produce repeated 4-s intervals of tetanus. During each tetanus interval, volume increments of different amplitudes were rapidly removed and then reinfused into the left ventricular chamber. The pressure responses to these volume changes were evaluated for differences between withdrawals and infusions and for dependence on the amplitude of the volume change. It was found for both withdrawal and infusion that the response could be divided into three phases: 1) an immediate phase coincident with volume change, 2) a fast-recovery phase, and 3) a slow-recovery phase. The amplitude of the immediate phase was linearly dependent on the volume change so that a single regression line fit all the data (withdrawal and infusion). The fast recovery phase was 2.5 times faster for infusion than for withdrawal and generated a rebound effect with the pressure going below the initial pressure in the response to infusion. The pressure never went above the initial pressure in the response to withdrawal. The slow-recovery phases in infusion and withdrawal did not differ. These responses in the isolated heart bear striking similarities to tension responses to quick length changes in isolated constantly activated cardiac muscle. We concluded that muscle fiber dynamics were being faithfully transformed to left ventricular (LV) chamber dynamics without appreciable distortion because of the many intervening factors between the wall muscle fiber and the LV chamber.(ABSTRACT TRUNCATED AT 250 WORDS)

A new simple system for measuring volume changes in unsaturated soils

2002 ◽  
Vol 39 (3) ◽  
pp. 757-764 ◽  
Author(s):  
C W.W Ng ◽  
L T Zhan ◽  
Y J Cui
Keyword(s):  
Volume Change ◽  
Unsaturated Soils ◽  
Volumetric Strain ◽  
Apparent Volume ◽  
Differential Pressure ◽  
Simple System ◽  
Measuring System ◽  
Volume Changes ◽  
Ambient Temperatures ◽  
Triaxial Apparatus

A new simple system for accurately measuring overall total volume changes in unsaturated soil specimens with a triaxial apparatus is introduced in this paper. The basic principle of the measuring system is to record changes in the differential pressure due to changes in the water level inside an open-ended, bottle-shaped inner cell caused by volume change in the specimen and inside a reference tube using an accurate differential pressure transducer. Several important steps were taken to improve the accuracy and sensitivity of the measuring system. Detailed calibrations were carried out to account for apparent volume changes as a result of changes in cell pressure, fluctuation in the ambient temperatures, creep in the inner cell wall, and relative movement between the loading ram and the inner cell. The calibration results demonstrate that the measuring system is reasonably linear, reversible, and repeatable. The estimated accuracy of the measuring system is in the order of 32 mm3 (or 0.04% volumetric strain for a triaxial specimen 38 mm in diameter and 76 mm in height) once the system is properly calibrated.Key words: unsaturated soils, volume-change measurement, open-ended, bottle-shaped, inner cell, differential pressure, calibration.

The Attack of Ozone on Stretched Rubber Vulcanizates. II. Conditions for Cut Growth

1960 ◽  
Vol 33 (4) ◽  
pp. 1156-1165
Author(s):  
M. Braden ◽  
A. N. Gent
Keyword(s):  
Experimental Study ◽  
Tensile Stress ◽  
Natural Rubber ◽  
Critical Value ◽  
Rubber Sheet ◽  
Test Pieces ◽  
Rubber Vulcanizate ◽  
Present Part ◽  
Applied Tensile Stress ◽  
Made In

Abstract In Part I an experimental study was reported of the factors determining the rate of propagation of a cut through a stretched rubber sheet under the action of an atmosphere containing ozone. It was remarked that no growth took place from a small razor cut made in one edge of the test pieces unless a critical value of the applied tensile stress was exceeded. The value was quite small, of the order of 100 g/cm2 for a soft natural rubber vulcanizate. In the present part an examination is reported of the conditions necessary for a crack to form or, being present, to grow.

Buccal Fat Pad Sculpting for Lower Facial Contouring With 3-Dimensional Volume Assessment

2020 ◽  
pp. 074880682098086
Author(s):  
Robert T. Cristel ◽  
Benjamin P. Caughlin
Keyword(s):  
Soft Tissue ◽  
Volume Change ◽  
3D Imaging ◽  
Fat Pad ◽  
Buccal Fat Pad ◽  
Volume Changes ◽  
Tissue Volume ◽  
Soft Tissue Volume ◽  
The Face ◽  
The Mean

Buccal fat pad sculpting and removal (BFPS) can create narrowing of the lower 1/3rd of the face by selective removal and reduction of soft tissue volume. Three-dimensional (3D) imaging allows for quantitative and objective assessment of volume changes over traditional 2-dimensional photographs that has not been previously studied in BFPS. A prospective study was designed in consecutive subjects undergoing BFPS from April 2018 through March 2020. Only those patients that underwent solely BFPS were included. VectraXT 3D imaging and software was used to compare preoperative and postoperative volume changes. Fifteen patients were enrolled in the study with 2 males and 13 females. The mean length of follow up was 7.7 months (range: 1-21 months). All patients were found to have volume reduction in the area evaluated. The mean volume reduction of the selected mid-lower face in the frontal view was 7.2 mL on the left side and 7.5 mL on the right side. There was no statistical difference between the volume change when the 2 sides were compared (P= 0.82). This study demonstrate the use of 3D photography to objectively and quantitatively assess volume change following BFPS and that the volume removed is significant enough to demonstrate favorable results using 3D imaging. Buccal fat pad sculpting is a safe and reliable option for creating a narrowed lower one-third of the face. This is accomplished by selective fat removal and cautery induced reduction of the lower one-third of the face soft tissue volume. VectraXT 3D imaging and analysis is a powerful tool to objectively and quantitatively assess volume changes in BFPS.

Dilatometric study of streptococcal growth and metabolism

1969 ◽  
Vol 15 (8) ◽  
pp. 933-940 ◽  
Author(s):  
Robert E. Marquis ◽  
Wallace O. Fenn
Keyword(s):  
Lactic Acid ◽  
Volume Change ◽  
Small Volume ◽  
Partial Molar Volumes ◽  
Pressure Sensitivity ◽  
Volume Changes ◽  
Streptococcus Faecalis ◽  
Dilatometric Study ◽  
Cell Synthesis ◽  
Metabolic Volume

A simply constructed dilatometer or volumeter was used to measure small volume changes (ca. 6 × 10−4 ml per milliliter) accompanying growth of Streptococcus faecalis cultures. Polymerization reactions involved in cell synthesis appeared to contribute little to the observed changes, and dilatation of cultures in glucose-containing media could be interpreted mainly in terms of volume changes associated with cleavage of glucose to lactic acid, ionization of lactic acid, and protonation of buffer ions in the culture. Glycolysis in suspensions of nongrowing cells was accompanied by similar increases in volume. In contrast, arginine degradation by S. faecalis was accompanied by contraction, and in this case the volume change could be almost completely accounted for by differences in partial molar volumes of products and reactants. Possible relationships between metabolic volume changes and pressure sensitivity of bacteria are discussed.

scholarly journals Elevation and volume changes on the Harding Icefield, Alaska

1998 ◽  
Vol 44 (148) ◽  
pp. 570-582 ◽  
Author(s):  
G. Adalgeirsdóttir ◽  
K. A. Echelmeyer ◽  
W. D. Harrison
Keyword(s):  
Volume Change ◽  
Geological Survey ◽  
Surface Elevation ◽  
Elevation Change ◽  
Volume Changes ◽  
South Central ◽  
Ice Field ◽  
The 1950S ◽  
Estimated Error ◽  
Made In

AbstractAirborne surface elevation profiles of the Harding Ice field, south-central Alaska, were made in 1991 and 1996. Thirteen glaciers were profiled, along with the tipper region of the icefield. The profiles were compared to U.S. Geological Survey topographie maps made in the 1950s, to obtain elevation and volume changes. Comparison of the changes for the different glaciers shows no significant correlation between volume change and the type of glacier or characteristics such as location, aspect, size, slope or terminus changes. Estimated total volume change tor this ~43 year period is about -34 km3, which corresponds to an area-average elevation change of-21 m. The estimated error in this elevation change of 5 m is mainly due to errors in the maps at higher elevations. Our measurements provide an accurate baseline against which future determinations of volume change can be made.

PVT Measurements on 4′-n-Octyl-Biphenyl-4-Carbonitrile (8CB) up to 300 MPa

1998 ◽  
Vol 53 (9) ◽  
pp. 787-792
Author(s):  
M. Sandmann ◽  
A. Würflinger
Keyword(s):  
Volume Change ◽  
Atmospheric Pressure ◽  
Volume Changes ◽  
First Order ◽  
Smectic A ◽  
Enthalpy Changes ◽  
Second Order Transition ◽  
Clearing Temperature ◽  
Pvt Measurements ◽  
Period Of Oscillation

Abstract P, Vm , Tdata have been measured for the smectic, nematic and isotropic phases of 4'-n-octyl-biphen-yl-4-carbonitrile (8CB) in the temperature range 300-370 K and pressures up to 300 MPa. At atmospheric pressure all phase transitions appear to be of first order due to a discontinuity in the density. The volume change at the smectic A -nematic transition is only a tenth of the volume change at the clearing temperature. At moderate pressures below 80 MPa the SA -N transition could be detected as a discontinuity in the period of oscillation in measurements with a high-pressure vibrating tube densimeter. At higher pressures the discontinuity seems to die away, possibly indicating a change from first order to second order transition. From the volume changes and the slopes of the transition lines we calculate the enthalpy changes at the phase transition. The p, Vm , T data enable us to calculate the volume part of the entropy and the molecular field parameter γ=δln TNI/δln VNI .

Heats of Reaction of Natural Rubber with Sulfur

1970 ◽  
Vol 43 (6) ◽  
pp. 1275-1293 ◽  
Author(s):  
N. Bekkedahl ◽  
J. J. Weeks
Keyword(s):  
Hydrogen Sulfide ◽  
Standard Deviation ◽  
Natural Rubber ◽  
Volume Change ◽  
Side Reaction ◽  
Enthalpy Change ◽  
Heat Of Reaction ◽  
Use Of Data ◽  
Heats Of Reaction

Abstract An adiabatic copper calorimeter was used to determine the heats of vulcanization of pale crepe natural rubber with sulfur for mixtures varying in composition from 0 to 32 per cent added sulfur. The side reaction that produces hydrogen sulfide was avoided by using reaction temperatures near 155° C. Heats of reaction at 25° C and at 155° C are reported. The enthalpy change at 25° C for compounds containing up to about 18 per cent sulfur is given in joules per gram of vulcanizate by the equation, ΔH25=−21.1·S with a standard deviation of 11 J/g. Here S is the percentage of combined sulfur. Above 18 per cent sulfur the heat of reaction at 25° C remains approximately constant at 380 ± 8 J/g. A comparison is made between the heat of vulcanization and the volume change on vulcanization, both as functions of combined sulfur, by making use of data in the literature.

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