Application of dn/dc Data for Determination of Partial Specific Volumes of Dissolved Macromolecules

1967 ◽  
Vol 40 (4) ◽  
pp. 1281-1295
Author(s):  
Wilfried Heller
Keyword(s):  
Specific Volume ◽  
Solution Process ◽  
Time Rate ◽  
Interpolation Procedure ◽  
Specific Volumes

Abstract The principles of a method are outlined whereby one can determine the partia specific volume of a solute, V, by means of measurements of dn/dc using a suitable pair of equations and a simple graphical interpolation procedure. The method yields V data which compare well with densitometrically obtained V data if the polarizability of both solvent and solute molecules is unaffected by the solution process. It is tested successfully on solutions of polystyrene in various solvents. The method appears to be particularly attractive for measurements of the change of V with temperature and also for conveniently following the time rate of changes in V such as during the coil → helix transition.

scholarly journals Calculation of changes in specific volumes of Fe – C system alloys depending on carbon content and temperatures

2019 ◽  
Vol 62 (8) ◽  
pp. 627-631 ◽  
Author(s):  
D. I. Gabelaya ◽  
Z. K. Kabakov ◽  
M. A. Mashchenko
Keyword(s):  
Specific Volume ◽  
Linear Expansion ◽  
Equilibrium Diagram ◽  
Continuous Cast ◽  
Equilibrium System ◽  
A New Technique ◽  
Coefficient Of Linear Expansion ◽  
Carbon Concentrations ◽  
Specific Volumes

The work presents a new technique for determining the temperature dependence of the alloy specific volumes in Fe – C equilibrium system based on known from the literature calculated and empirical dependence for account of the phases’ specific volumes. These data were based on the independent reports of S.F. Yuryev and were obtained for temperatures below 1200 °C. When using these forms at temperatures above 1200 °C, the specific volume of austenite exceeds specific volume of ferrite. However, it is known that austenite has the smallest specific volume among all phases of the Fe – C system. In this regard, in the field of high temperatures, it is proposed to use other dependences that do not contradict the physics of polymorphic and phase transformations in this system. Thus the authors have obtained the general expressions for calculating the alloys’ specific volumes separately for three intervals of carbon concentrations in which the change in shares of the temperature phases are calculated according to Fe – C equilibrium diagram using the lever relation. As an example, results of the calculated determination of specific volumes of alloys with carbon vontent of 0.05, 0.13 and 0.33 % in the temperature range of 20 – 1600 °C are considered. The presented results are compared with the results obtained with the help of the phase diagram calculation package JMatPro®, on the basis of which the adequacy of the proposed calculation method was established. The developed technique can be used to calculate not only specific volumes of alloys, but also their density and coefficient of linear expansion depending on temperature and carbon concentration. It is the basis for the correct use of methods for determining the size of continuous cast billets due to shrinkage in order to correctly configure the equipment of continuous casting machines.

THE DETERMINATION OF PARTIAL SPECIFIC VOLUMES BY DIFFERENTIAL SEDIMENTATION

1956 ◽  
Vol 34 (6) ◽  
pp. 809-814 ◽  
Author(s):  
W. G. Martin ◽  
W. H. Cook ◽  
C. A. Winkler
Keyword(s):  
Polyvinyl Alcohol ◽  
Sodium Alginate ◽  
Heavy Water ◽  
Specific Volume ◽  
Partial Specific Volume ◽  
Plasma Albumin ◽  
Bovine Plasma ◽  
Differential Sedimentation ◽  
Specific Volumes

Sedimentation in aqueous and heavy water solutions has been used to determine the partial specific volume of bovine plasma albumin, sodium alginate, and polyvinyl alcohol, resulting in 0.74 ± 0.01 (S.D.), 0.54 ± 0.06, and 0.79 ± 0.01 ml./gm. at 25 °C, respectively. The sedimentation method yields results comparable with those given by conventional methods for macromolecules.

Device for the Experimental Determination of Control Objects' Mathematical Models

2013 ◽  
Vol 650 ◽  
pp. 493-497 ◽  
Author(s):  
Valerij I. Goncharov ◽  
Vadim A. Onufriev ◽  
Ilya O. Ilyin
Keyword(s):  
Control Systems ◽  
Computer Technology ◽  
Interpolation Method ◽  
Facilities Management ◽  
Operational Conditions ◽  
Automatic Control Systems ◽  
Interpolation Procedure ◽  
Real Interpolation Method ◽  
Inverse Problems Of Dynamics

Authors review methods of determining a plant’s mathematical model. Then, they show a numerical method of pulse automatic control systems’ (ACS) identification, focused on computer technology, the interpolation procedure and iterative methods of approximation to the desired solution. The basis of the approach is the method of inverse problems of dynamics and real interpolation method for calculating the linearized dynamical systems. An algorithm and the mobile device designed for the identification of facilities management in operational conditions are proposed. There is results’ application in the conclusion.

scholarly journals Experimental and Theoretical Study on Three Combustion Models for the Determination of the Performance Parameters of Nitrocellulose - Based Propellants

2020 ◽  
Vol 71 (9) ◽  
pp. 87-97
Author(s):  
Titi Paraschiv ◽  
Tudor Viorel Tiganescu ◽  
George Ovidiu Iorga ◽  
Raluca Elena Ginghina ◽  
Octavian Constantin Grigoroiu
Keyword(s):  
Chemical Composition ◽  
Energetic Materials ◽  
Specific Volume ◽  
Flame Temperature ◽  
Performance Parameters ◽  
Heat Of Explosion ◽  
Combustion Gases ◽  
Combustion Models ◽  
Double Base

Nitrocellulose based propellants are the main materials used for ballistic and rocket applications. The chemical composition of the propellants, the loading density and propellant grain geometry are the decisive parameters that influence the performance parameters in ballistic application. In this paper the authors evaluate three models of combustion for energetic materials for the determination of heat of explosion and specific volume together with the adiabatic flame temperature. The authors select six types of propellant (two simple base propellants, two double base propellants based on nitroglycerine and two triple base propellants based on nitroguanidine) and the authors determined the heat of explosion and specific volume using a bomb calorimeter and a Julius-Peters device. The results obtained from the combustion models were compared to the experimental results and assumptions were done on the influence of pressure and temperature on the chemical composition of combustion gases produced by the confined deflagration of nitrocellulose-based propellants.

scholarly journals Determination of partial specific volume and absolute concentration by densimetry

1984 ◽  
Vol 219 (3) ◽  
pp. 1049-1052 ◽  
Author(s):  
P H Stothart
Keyword(s):  
Absorption Coefficient ◽  
Neutron Scattering ◽  
Prior Knowledge ◽  
Small Angle ◽  
Specific Volume ◽  
Small Angle Neutron Scattering ◽  
Partial Specific Volume ◽  
Absolute Concentration ◽  
Non Destructive

The apparent partial specific volume, phi, of a protein (or other macromolecule) and the absolute concentration, c, can be determined from the densimetry of solutions and diffusates in 1H2O, 2H2O and 1H2O/2H2O mixtures if the ratios of concentrations (relative concentrations) are known. The densimetry method allows a non-destructive check on total macromolecule concentrations without prior knowledge of specific u.v.-absorption coefficient. The method may be especially useful in small-angle neutron-scattering studies.

Infrared Determination of Dithianon

1969 ◽  
Vol 52 (3) ◽  
pp. 659-662
Author(s):  
R C Double
Keyword(s):  
Infrared Absorption ◽  
Spectrophotometric Method ◽  
Specific Volume

Abstract An infrared spectrophotometric method of analysis of dithianon in concentrates and formulated powders containing zineb and sulfur has been developed. Dithianon is extracted with chloroform from the concentrate or formulation; the extract is evaporated and diluted to a specific volume with chloroform; and the dithianon present is determined from the infrared absorption at 1275 cm-1. From 20 to 80 mg dithianon in 10 ml chloroform are readily determined.

Isotope shifts in the Cl2B–X system

1988 ◽  
Vol 66 (8) ◽  
pp. 721-723
Author(s):  
G. Gouédard ◽  
N. Billy ◽  
B. Girard ◽  
J. Vigué
Keyword(s):  
Excitation Spectrum ◽  
Fluorescence Excitation Spectrum ◽  
Abundant Species ◽  
Precise Determination ◽  
Dye Laser ◽  
Fluorescence Excitation ◽  
Isotope Shifts ◽  
Quantum Numbers ◽  
Interpolation Procedure

We have studied the fluorescence excitation spectrum of natural Cl2 molecules induced by a monomode ring dye laser around various X(ν″ = 0) → B(ν′ ≥ 18) bandheads. Contrary to the main 35–35Cl2 isotope, the less abundant species 35–37Cl2 and 37–37Cl2 have not, up to now, been thoroughly investigated in this region. Our experiment has allowed a precise determination of a number of isotope shifts, which are shown to be calculable by a local interpolation procedure of Coxon's data, using the concept of mass-reduced quantum numbers.

scholarly journals Packing volume of sedimented microtubules: regulation and potential relationship to an intracellular matrix.

1985 ◽  
Vol 101 (4) ◽  
pp. 1492-1500 ◽  
Author(s):  
P A Brown ◽  
R D Berlin
Keyword(s):  
Theoretical Analysis ◽  
Specific Volume ◽  
Mechanical Stability ◽  
Large Fraction ◽  
Bovine Brain ◽  
Associated Proteins ◽  
Irreducible Space ◽  
Specific Volumes

To determine the contribution of microtubules to a hypothetical intracellular matrix, we have analyzed the space occupied by microtubules in vitro. Taxol-stabilized microtubules assembled from purified (three-times-cycled) bovine brain microtubule protein were pelleted by centrifugation under standardized conditions. The specific volume of the pellet, defined as the microliter volume per milligram protein, was 22.4. As suggested by others, this volume was strongly dependent on microtubule-associated proteins (MAPs), as shown by quantitation of the effects of purified MAP supplementation on specific volume. The specific volumes of microtubule pellets stripped of MAPs by high salt or chymotryptic digestion approached the mathematically optimal (least occupied space) and increased 14-fold with the highest MAP concentrations employed. Packing was also dependent on pH. Specific volumes comparable to those of MAP-depleted microtubules were attainable at pH's from 5.5 to 6.0, and specific volumes more than doubled at pH 7.5. MAP content was unaffected by pH. We present a theoretical analysis that suggests that as microtubules are centrifuged the mixture behaves as a liquid crystal. With packing, the mixture undergoes an isotropic-nematic phase transition in which the microtubules become oriented principally as parallel rods, mimicking their orientation in vivo. From the known concentration of microtubules in vivo, it can be inferred from our measurements that in some cells a large fraction, perhaps 40-50% of the cytosolic volume, is occupied by microtubules that form a mechanically irreducible space. Further theoretical analysis employing Ogston's formulation of the penetrability of fibrous networks suggests that the space between microtubules (in contrast to the extracellular matrix) imposes little barrier to the diffusion of macromolecules. A microtubule array thus achieves mechanical stability without affecting transport by diffusion. The space can accommodate other fibrous networks that could then affect transport, and, as we show, the space itself may be regulated by MAP content and intracellular pH.

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