Apparatus for the Direct Determination of the Dynamic Bulk Modulus

1957 ◽  
Vol 30 (2) ◽  
pp. 449-459
Author(s):  
J. E. McKinney ◽  
S. Edelman ◽  
R. S. Marvin
Keyword(s):  
Natural Rubber ◽  
Bulk Modulus ◽  
Direct Measurement ◽  
Static Pressure ◽  
Direct Determination ◽  
Preliminary Evaluation ◽  
Air Bubbles ◽  
Frequency Range ◽  
Piezoelectric Crystals

Abstract An apparatus has been developed for the direct measurement of the real and imaginary parts of the dynamic bulk modulus of solid and liquid materials over the frequency range of 50 to 10,000 cps. Piezoelectric crystals serving as driver and detector, together with the sample and a confining liquid, are contained in a cavity small compared with the wavelength of sound at these frequencies. Static pressure is superposed to eliminate the effect of small air bubbles. The complex compliances of the sample, confining liquid, and the cavity, are additive in this region, where the compliance is pure dilatation. The dynamic compliances of several natural rubber-sulfur mixtures were obtained in a preliminary evaluation of the behavior of the apparatus.

scholarly journals Snow Stratigraphy and Water Equivalence Measured With an Active Microwave System

1980 ◽  
Vol 26 (94) ◽  
pp. 225-233
Author(s):  
D. A. Ellerbruch ◽  
H. S. Boyne
Keyword(s):  
Electromagnetic Scattering ◽  
Direct Determination ◽  
Snow Pack ◽  
Frequency Range ◽  
Microwave Radar ◽  
Snow Stratigraphy ◽  
Microwave System ◽  
The Relationship ◽  
System Operating

AbstractThis paper reports on research on the relationship between the electromagnetic scattering properties and physical properties of snow-pack. An FM-CW active microwave radar system operating in the frequency range 8-12 GHz is used to scatter electromagnetic radiation from surface and subsurface stratigraphic layers in the snow-pack. The amplitude of the scattered radiation as a function of depth in the snow-pack can be correlated with such physical characteristics as density, hardness, stratigraphy, and moisture content. A direct determination of snow-pack water equivalence can be made from these observations.

Snow Stratigraphy and Water Equivalence Measured With an Active Microwave System

1980 ◽  
Vol 26 (94) ◽  
pp. 225-233 ◽  
Author(s):  
D. A. Ellerbruch ◽  
H. S. Boyne
Keyword(s):  
Electromagnetic Scattering ◽  
Direct Determination ◽  
Snow Pack ◽  
Frequency Range ◽  
Microwave Radar ◽  
Snow Stratigraphy ◽  
Microwave System ◽  
The Relationship ◽  
System Operating

Abstract This paper reports on research on the relationship between the electromagnetic scattering properties and physical properties of snow-pack. An FM-CW active microwave radar system operating in the frequency range 8-12 GHz is used to scatter electromagnetic radiation from surface and subsurface stratigraphic layers in the snow-pack. The amplitude of the scattered radiation as a function of depth in the snow-pack can be correlated with such physical characteristics as density, hardness, stratigraphy, and moisture content. A direct determination of snow-pack water equivalence can be made from these observations.

Determination of Dynamic Bulk Modulus of Elastomers Using Pressure Measurement

1993 ◽  
Vol 66 (5) ◽  
pp. 749-753 ◽  
Author(s):  
B. P. Holownia ◽  
E. H. James
Keyword(s):  
Bulk Modulus ◽  
Pressure Measurement ◽  
Frequency Range ◽  
Novel Method ◽  
Pressure Changes

Abstract A novel method of determining dynamic bulk modulus of elastomers, by measurement of pressure changes of the fluid in which the specimen is immersed, was successful in principle. The frequency range covered was between 100 Hz and 1200 Hz which was limited by the power of the oscillator used.

Apparatus for the Direct Determination of the Dynamic Bulk Modulus

1956 ◽  
Vol 27 (5) ◽  
pp. 425-430 ◽  
Author(s):  
John E. McKinney ◽  
Seymour Edelman ◽  
Robert S. Marvin
Keyword(s):  
Bulk Modulus ◽  
Direct Determination

A New Method for the Direct Determination of Rubber. A Preliminary Communication

1938 ◽  
Vol 11 (2) ◽  
pp. 438-438
Author(s):  
E. Kheraskova ◽  
E. Korsunskaya
Keyword(s):  
Acetic Acid ◽  
Natural Rubber ◽  
Direct Determination ◽  
Methyl Groups ◽  
Butadiene Rubber ◽  
Double Bonds ◽  
Synthetic Rubber ◽  
Oxidation Of Organic Compounds ◽  
Preliminary Communication

Abstract The conventional methods for the direct determination of rubber cannot be used for determining natural rubber in the presence of sodium-butadiene rubber. These methods are based either on precipitation of the rubber from solution or on the determination, by one method or another, of the double bonds in the rubber molecule. Since natural rubber and synthetic rubber differ in their solubilities but little, the method of precipitation obviously cannot be used for their separation. Nor are methods which involve determining the double bonds adequate to distinguish them, because both kinds of rubber are unsaturated compounds. It was therefore of interest to develop a method of analysis based on the determination of the methyl groups, which are present only in the natural rubber molecule. Kuhn and L'Orsa (Z. angew. Chem., 44, 847 (1931)) have shown that, in the oxidation of organic compounds, a methyl group connected with a carbon atom is partially oxidized to acetic acid. The object was to develop this reaction into a method of rubber analysis by establishing the optimum conditions for the quantitative oxidation to acetic acid of all the methyl groups in the rubber hydrocarbon.

scholarly journals Direct Measurement of cGMP in Blood Plasma and Urine by Radioimmunoassay

1978 ◽  
Vol 15 (1-6) ◽  
pp. 25-30 ◽  
Author(s):  
P. J. Wood ◽  
V. Marks
Keyword(s):  
Blood Plasma ◽  
Direct Measurement ◽  
Direct Determination ◽  
In Blood Plasma

Antisera, raised against 2′-O-succinyl-cGMP conjugated to ovalbumin or kehole limpet haemocyanin, have been used to develop radioimmunoassays for the direct determination of urine and plasma cGMP levels. Details of these assays are presented, together with evidence for their validity.

Errors Associated with the Direct Measurement of Human Serum Cholesterol Using the FeCI3 Color Reagent

1963 ◽  
Vol 9 (2) ◽  
pp. 156-162 ◽  
Author(s):  
Robert V Moore ◽  
Edwin Boyle
Keyword(s):  
Acetic Acid ◽  
Human Serum ◽  
Direct Measurement ◽  
Ferric Chloride ◽  
Serum Cholesterol ◽  
Direct Determination ◽  
Color Reagent ◽  
High Bilirubin

Abstract Evidence is presented concerning errors in the direct determination of human serum cholesterol with a ferric-chloride color reagent. It is shown that in physiologic concentrations the vitamins A, D, E, K, and niotinic acid cause no error, but that hemoglobin, anticoagulants, and impurities in acetic acid can cause errors. The control of these errors is discussed. Errors caused by steroids, added salts, and high bilirubin content of serum are discussed.

Determination of Rubber Hydrocarbon by a Gravimetric Rubber Bromide Method

1947 ◽  
Vol 20 (1) ◽  
pp. 320-328 ◽  
Author(s):  
C. O. Willits ◽  
M. L. Swain ◽  
C. L. Ogg
Keyword(s):  
Natural Rubber ◽  
Physical Properties ◽  
Difference Method ◽  
Direct Determination ◽  
Chemical Processes ◽  
Rubber Content ◽  
Low Concentration ◽  
Hydrocarbon Analysis ◽  
The Difference

Abstract Direct determination of rubber hydrocarbon in crude rubbers and in latices has been generally considered so inaccurate and unreliable that determination of rubber hydrocarbon by difference has been a common practice. The difference method usually suffices in the analysis of products derived from Hevea rubber, in which the nonrubber components have been well characterized or occur in low concentration. In the analysis of natural rubber products obtained from sources other than Hevea, such as guayule, kok-saghyz, and Cryptostegia, the situation is different. The chemical and physical properties of the nonrubber components of such products are largely unknown, and in many cases the nonrubber contaminants are present in excessive amounts, sometimes more than 50 per cent of the total. Since the rubber hydrocarbon analysis usually affords the most reliable means for estimating the rubber content of plants and for following the concentration and purification of rubber by mechanical and chemical processes, it appeared desirable to devise or adapt a method which would permit direct determination of this constituent in the presence of relatively large amounts of natural and added contaminants.

scholarly journals Direct Quantitation of the Numbers of Individual Penicillin-Binding Proteins per Cell in Staphylococcus aureus

2002 ◽  
Vol 184 (2) ◽  
pp. 588-591 ◽  
Author(s):  
Michael J. Pucci ◽  
Thomas J. Dougherty
Keyword(s):  
Staphylococcus Aureus ◽  
Direct Measurement ◽  
Binding Proteins ◽  
Specific Activity ◽  
Direct Determination ◽  
Absolute Number ◽  
Penicillin Binding Proteins ◽  
The Absolute ◽  
Bacterial Peptidoglycan

ABSTRACT The penicillin-binding proteins (PBPs) are a set of enzymes that participate in bacterial peptidoglycan assembly. The absolute numbers of each PBP were determined by direct measurement and have been reported for two Staphylococcus aureus strains, RN4220 (methicillin-sensitive S. aureus) and RN450M (methicillin-resistant S. aureus). From the specific activity of the labeled penicillin and the absolute number of disintegrations per minute, and from the number of CFU per milliliter calculated from proteins and optical density, a determination of the number of PBPs per cell was made. These numbers ranged from approximately 150 to 825 PBPs/cell and represent the first direct determination of absolute numbers of PBPs in S. aureus.

The Direct Determination of I131 in Heterogeneous Fecal Specimens

1961 ◽  
Vol 41 (4) ◽  
pp. 380-384 ◽  
Author(s):  
Arthur F. Dratz ◽  
James C. Coberly
Keyword(s):  
Direct Determination
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