Effect of the Compatibility of Rubbers on the Viscous Flow Properties of Their Binary Mixtures

1973 ◽  
Vol 46 (5) ◽  
pp. 1188-1192 ◽  
Author(s):  
G. S. Kongarov ◽  
G. M. Bartenev
Keyword(s):  
Strain Rate ◽  
Viscous Flow ◽  
Binary Mixtures ◽  
Binary Systems ◽  
Flow Properties ◽  
Entrance Effect ◽  
The Individual

Abstract The viscosity of binary systems of incompatible polymers is lower than that of the individual rubbers. In the case of compatible polymers, the viscosity of the systems changes additively with its composition or may increase somewhat. The degree of compatibility of the polymers affects the size of the entrance effect and the character of its dependence on strain rate.

scholarly journals Powder properties of binary mixtures of chloroquine phosphate with lactose and dicalcium phosphate

2010 ◽  
Vol 46 (3) ◽  
pp. 531-537
Author(s):  
Michael Ayodele Odeniyi ◽  
Collins Chidi Onyenaka ◽  
Oludele Adelanwa Itiola
Keyword(s):  
Binary Mixtures ◽  
Internal Flow ◽  
Optical Microscope ◽  
Volume Reduction ◽  
Dicalcium Phosphate ◽  
Flow Properties ◽  
Maximum Volume ◽  
Cohesive Properties ◽  
Particle Size And Shape ◽  
The Individual

A study was conducted on the packing and cohesive properties of chloroquine phosphate in binary mixtures with lactose and dicalcium phosphate powders. The maximum volume reduction due to packing as expressed by the Kawakita constant, a, and the angle of internal flow, θ, were the assessment parameters. The individual powders were characterized for their particle size and shape using an optical microscope. Binary mixtures of various proportions of chloroquine phosphate with lactose and dicalcium phosphate powders were prepared. The bulk and tapped densities, angles of repose and internal flow, as well as compressibility index of the materials were determined using appropriate parameters. The calculated and determined values of maximum volume reduction for the binary mixtures were found to differ significantly (P< 0.05), with the Kawakita plot being more reliable in determining the packing properties. Diluent type was found to influence the flow properties of the mixtures, with dicalcium phosphate giving predictable results while mixtures containing lactose were anomalous with respect to flow. The characterization of the packing and cohesive properties of the binary mixtures of chloroquine with lactose and dicalcium phosphate would be useful in the production of powders, tablets, capsules and other drug delivery systems containing these powders with desirable and predictable flow properties.

scholarly journals Thermal and Photophysical Studies of Binary Mixtures of Liquid Crystal with Different Geometrical Mesogens

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 223 ◽  
Author(s):  
Omaima A. Alhaddad ◽  
Hoda A. Ahmed ◽  
Mohamed Hagar ◽  
Gamal R. Saad ◽  
Khulood A. Abu Al-Ola ◽  
...  
Keyword(s):  
Binary Mixtures ◽  
Density Functional ◽  
Binary Systems ◽  
Uv Spectroscopy ◽  
Twist Angle ◽  
Optical Microscope ◽  
Geometrical Parameters ◽  
Scanning Calorimetry ◽  
Photophysical Studies ◽  
The Individual

Three binary systems were prepared by mixing of two different mesogenic derivatives, homologues, the first is azo/ester, namely 4-alkoxyphenylazo-4′-phenyl-4″-alkoxybenzoates (IIn+m) and the second is Schiff base/ester, namely 4-(arylideneamino)phenyl-4″-alkoxy benzoates (In+m). The two corresponding analogues from both series in the binary mixtures investigated are of the same terminal alkoxy chain length. Mesomorphic properties were investigated by differential scanning calorimetry (DSC) and phases identified by polarized optical microscope (POM). Photophysical studies were investigated by UV spectroscopy connected to a hot stage. Results were discussed based on constructed binary phase diagrams. All mixtures were found to exhibit eutectic compositions, with linear or slightly linear nematic and smectic A stability/composition dependences. Geometrical parameters were predicted applying density functional theory (DFT) calculations. Twist angle (θ), aspect ratio, dipole moment and the polarizability of the individual compounds were discussed and correlated with the experimental results to illustrate the enhanced the mesophase stability and the mesophase range of the mixture at the eutectic composition compared with those of their individual components.

scholarly journals Double-Peaked Flare Events on red Dwarf Stars and Solar ‘Sympathetic’ Flares

1976 ◽  
Vol 71 ◽  
pp. 475-475
Author(s):  
M. Rodonò
Keyword(s):  
Proximity Effect ◽  
Binary Systems ◽  
Angular Separation ◽  
Dwarf Stars ◽  
Multiple Systems ◽  
Photometric Observations ◽  
Red Dwarfs ◽  
Flare Stars ◽  
Red Dwarf Stars ◽  
The Individual

About 50% of the flare events observed on red dwarfs are at least double-peaked. As the majority of flare stars are members of double or multiple systems, the possibility that time-overlapping flares originate quasi-simultaneously on the individual components is discussed.Assuming a poissonian occurrence of flares in both components, the expected probability of observing double-peaked flares is lower than 1% for the most active binary systems.However, from photometric observations of the double flare star EQ Peg (BD +19°5116 AB) carried out by the author with an area scanner (the components' angular separation is 3.7″) about 20% of the observed flares have been found to be double-peaked flares resulting from separate flares, one in each component. A direct flare triggering of the following flare by the preceding one can be ruled out since the light travel-time between the two components is 3.5 h, while the observed time delay between the flare peaks is about 10 min. Moreover, the proximity effect does not seem to play an important triggering role.It is concluded that, although the analogy with solar ‘sympathetic’ flares is not always applicable, it is the most promising framework within which the majority of double-peaked flare events on red dwarfs must be interpreted.

scholarly journals Ολοκληρωμένη συστοιχία αισθητήρων βασισμένη σε πολυμερή για την αναγνώριση πτητικών αερίων

2012 ◽  
Author(s):  
Πέτρος Οικονόμου
Keyword(s):  
Binary Mixtures ◽  
Sensor Array ◽  
Gas Sensing ◽  
Limit Of Detection ◽  
Principal Component ◽  
Polymeric Materials ◽  
Integrated Sensor ◽  
Electromagnetic Model ◽  
The Individual ◽  
Electronic Elements

In this research the sensor type of planar InterDigitated Capacitors (IDCs), also known as chemcapacitors, is demonstrated and its application in the detection of Volatile Organic Compounds (VOCs) and humidity is explored. The IDC layout configuration is studied by using a dedicated electromagnetic model and the behavior of different planar IDE structures/geometries coated with different polymeric materials of different dielectric permittivity values (εp) is determined. This study leads to the optimum design geometry of the planar IDCs that will be used for the detection of analytes. In order to identify the more suitable sensing materials for the targeted application, a methodology based on swelling measurements of the polymeric material upon exposure to analytes of interest was developed and applied in the prediction of the response of a chemcapacitor upon exposure to different VOCs. The integrated sensor array is characterized by the responses of each sensor to exposure to several pure analytes, binary mixtures of analytes and complex environments. Several parameters were examined such as sensitivity, selectivity, limit of detection, aging. Also the total response of the sensor array is analyzed by conjunction of the individual responses of each sensor and the use of suitable Principal Component Analysis, PCA, models that have been developed. Fabrication of a hybrid low-power gas sensing module is presented. This module is realized with integration on the same device of the sensor array with the appropriate electronic elements. The latter provide the power, control and read-out electronics of the output signal. The proposed hybrid micro-device is characterized in terms of the response of each sensor of the sensor array upon exposure to different pure analytes and their binary mixtures. Evaluation of the results obtained by the characterization of the hybrid gas sensing module demonstrate the ability of use such a device in analytical methods under conditions of constant or alterable concentration of VOCs/humidity or their mixtures in applications either at constant temperature or at temperature changing over time simulating that way real time applications.

Excess molar volumes and viscosities of binary mixtures of some polyethers with propylamine at 298.15 K

2002 ◽  
Vol 80 (5) ◽  
pp. 467-475 ◽  
Author(s):  
Amalendu Pal ◽  
Rakesh Kumar Bhardwaj
Keyword(s):  
Experimental Data ◽  
Viscous Flow ◽  
Binary Mixtures ◽  
Entire Range ◽  
Excess Volume ◽  
Excess Molar Volumes ◽  
Liquid Mixtures ◽  
Molar Volumes ◽  
Binary Liquid ◽  
Volume Viscosity

Excess molar volumes (VmE) and dynamic viscosities (η) have been measured as a function of composition for binary liquid mixtures of propylamine with 2,5-dioxahexane, 2,5,8-trioxanonane, 2,5,8,11-tetraoxadodecane, 3,6,9-trioxaundecane, and 5,8,11-trioxapentadecane at 298.15 K. The excess volumes are positive over the entire range of composition for the systems propylamine + 2,5-dioxahexane, and + 3,6,9-trioxaundecane, negative for the systems propylamine + 2,5,8,11-tetraoxadodecane, and + 5,8,11-trioxapentadecane, and change sign from positive to negative for the remaining system propylamine + 2,5,8-trioxanonane. From the experimental data, deviations in the viscosity (Δln η) and excess energies of activation for viscous flow (ΔG*E) have been derived. These values are positive for all mixtures with the exception of propylamine + 2,5-dioxahexane.Key words : excess volume, viscosity, binary mixtures.

Viscous-flow properties of acetone solutions of vinylidene fluoride ? tetrafluoroethylene copolymer

1983 ◽  
Vol 14 (3) ◽  
pp. 210-211
Author(s):  
B. S. Vesaite ◽  
A. Girlyavichyus ◽  
A. I. Logvinov ◽  
L. Ya. Madorskaya ◽  
A. V. Bezprozvannykh ◽  
...  
Keyword(s):  
Viscous Flow ◽  
Vinylidene Fluoride ◽  
Flow Properties

scholarly journals Observational Evidence for Mass Exchange in Close Binary Systems

1977 ◽  
Vol 42 ◽  
pp. 371-382
Author(s):  
Horst Drechsel ◽  
Jürgen Rahe ◽  
Gudrun Wolfschmidt ◽  
Yoji Kondo ◽  
George E. McCluskey
Keyword(s):  
Northern Hemisphere ◽  
Mass Exchange ◽  
Binary Systems ◽  
Variable Stars ◽  
Observational Evidence ◽  
Close Binary ◽  
Wide Angle ◽  
Close Binary Systems ◽  
The Individual

In 1925 a photographic search for new variable stars was begun at the Remeis-Observatory in Bamberg. Initially the sky patrol covered only the northern hemisphere, but in 1964 it was also extended to the southern sky. At the individual observing stations, the sky is systematically photographed with several wide-angle patrol cameras which are attached to the same mounting, and which have f/6 Tessar lenses of 4-inch aperture. Each camera covers a 13-by-13 degree field. The plates are usually exposed for one hour and a photographic magnitude of 14m is reached.

scholarly journals Origin of Binary Systems

1992 ◽  
Vol 151 ◽  
pp. 9-19
Author(s):  
Peter Bodenheimer
Keyword(s):  
Angular Momentum ◽  
Binary Systems ◽  
Theoretical Calculations ◽  
Pressure Effects ◽  
Close Binaries ◽  
Rotating Stars ◽  
Multiple Systems ◽  
The Individual ◽  
Protostellar Collapse ◽  
Three Body

Recent observational studies of the properties of binary systems among young stars indicate that the majority of binaries are formed very early in the history of a star, perhaps during the protostellar collapse. Major observational facts to be explained include the overall binary frequency, the non-negligible occurrence of multiple systems, and the distributions of period, eccentricity, and mass ratio among the individual binaries. Theoretical calculations of the collapse of rotating protostars during the isothermal phase indicate instability to fragmentation into multiple systems. This process in general produces systems with periods greater than a few hundred years, although somewhat shorter periods are possible. Fragmentation during later, optically thick, phases of collapse tends to be suppressed by pressure effects. Therefore, major theoretical problems remain concerning the origin of close binaries. Fission of rapidly rotating stars, tidal capture, and three-body capture have been shown to be improbable mechanisms for formation of close binaries. Mechanisms currently under study include gravitational instabilities in disks, orbital interactions and disk-induced captures in fragmented multiple systems, hierarchical fragmentation, and orbital decay of long-period systems. Single stars, on the other hand, could result by escape from multiple systems or by the collapse of clouds of low angular momentum, coupled with angular momentum transport after disk formation.

scholarly journals Colliding Stellar Winds in O-type Close Binary Systems

1992 ◽  
Vol 135 ◽  
pp. 146-148
Author(s):  
D.R. Gies ◽  
M.S. Wiggs
Keyword(s):  
Binary Systems ◽  
Optical Emission ◽  
Emission Lines ◽  
Optical Observations ◽  
Close Binary ◽  
High Dispersion ◽  
Stellar Winds ◽  
Close Binary Systems ◽  
Circumstellar Gas ◽  
The Individual

In close binary systems of O-type stars, the individual stellar winds will collide between the stars to form shock fronts (Stevens et al. 1992). Binaries with equally luminous stars will have winds of comparable strength, and the shock will occur near the mid-plane between the stars, but in binaries of unequal luminosity, the interaction will occur along a bow shock wrapped around the star with the weaker wind. The presence of the shock region can be detected through excess X-ray emission (Chlebowski & Garmany 1990), and orbital phase-related variations in the UV P Cygni lines (Shore & Brown 1988) and optical emission lines (formed in high density regions of circumstellar gas).We have begun a search for colliding winds through a study of the optical emission lines and UV P Cygni lines in four massive binaries, AO Cas (Gies & Wiggs 1991), Plaskett’s star = HD 47129 (Wiggs & Gies 1992), 29 UW CMa and ι Ori. The optical observations consist of high S/N spectra of the Hα and He I λ6678 region obtained with the University of Texas McDonald Observatory 2.1-m telescope and coudé Reticon system. The UV observations were culled from archival IUE high dispersion spectra of several P Cygni features (N V λ1240, Si IV λ1400, C IV λ1550).

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