The effect of temperature on sedimentation volume of pigment suspensions

1959 ◽  
Vol 162 (1) ◽  
pp. 47-47 ◽  
Author(s):  
Leopold Dintenfass
Keyword(s):  
Effect Of Temperature ◽  
Sedimentation Volume

scholarly journals EVALUATION OF THE SUSPENDING PROPERTIES OF A NEW PLANT GUM IN SULPHAMETOXAZOLE FORMULATIONS

2017 ◽  
pp. 47-50
Author(s):  
John Oluwasogo AYORINDE ◽  
Michael Ayodele ODENIYI
Keyword(s):  
Flow Rate ◽  
Volume Flow Rate ◽  
Dosage Forms ◽  
Volume Flow ◽  
Effect Of Temperature ◽  
Cedrela Odorata ◽  
Natural Polymer ◽  
Sedimentation Volume ◽  
Suspending Agents ◽  
Natural Gum

Suspension dosage forms require the use of suspending agents in order to deliver a uniform dose of the active ingredient. The purpose of this study is to investigate the properties of a new plant gum as a cheap and effective natural polymer in the formulation of pharmaceutical suspensions. The gum obtained from the incised trunk of Cedrela odorata (family Meliaceae) was compared with hydroxypropylmethylcellulose and gelatin in Sulphamethoxazole suspension formulations at concentrations of 1.0 – 4.0%w/w. Assessment parameters were sedimentation volume, flow rate, viscosity and the effect of temperature on these parameters. The suspending characteristics of Cedrela gum compared well with that of hydroxypropylmethylcellulose in term of sedimentation volume, flow rate and viscosity and the natural gum could be used as a substitute in pharmaceutical suspensions.

scholarly journals THE EFFECT OF TEMPERATURE ON SUSPENSIONS OF GLASS BEADS IN TOLUENE CONTAINING VARIOUS PERCENTAGES OF WATER

1954 ◽  
Vol 32 (2) ◽  
pp. 86-93 ◽  
Author(s):  
A. E. J. Eggleton ◽  
I. E. Puddington
Keyword(s):  
Room Temperature ◽  
Relative Yield ◽  
Glass Beads ◽  
Effect Of Temperature ◽  
Steady Increase ◽  
Equilibrium Sedimentation ◽  
Yield Value ◽  
Influence Of Temperature On ◽  
Yield Values ◽  
Sedimentation Volume

The influence of temperature on the sedimentation volume and relative yield values of suspensions of spherical glass beads in toluene containing varying percentages of water has been measured. The increased sedimentation volume and yield value, due to the presence of water, found at room temperature virtually disappeared below approximately 0 °C. This is in agreement with the theory which ascribes the effect of water to its interfacial tension against toluene. At temperatures above 0 °C. there was a gradual fall in the sedimentation volume and yield value from the maximum found at 0 °C. This is attributed to the increasing solubility of water in toluene. Suspensions containing no water or only a small quantity showed an unexpected steady increase in sedimentation volume and yield value as the temperature was lowered to −60 °C. This effect was also observed with a suspension of glass beads in pentane. The results indicate a close connection between yield value and equilibrium sedimentation volume.

Nucleation of Disorder in Fe3Al Alloys

1967 ◽  
Vol 25 ◽  
pp. 312-313
Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
Antiphase Domain ◽  
Effect Of Temperature ◽  
Domain Structures ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Higher Temperature ◽  
The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

The effect of temperature on high-resolution TEM image contrast

1995 ◽  
Vol 53 ◽  
pp. 640-641
Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz
Keyword(s):  
Form Factor ◽  
Inelastic Scattering ◽  
Accurate Method ◽  
Waller Factor ◽  
Effect Of Temperature ◽  
Specimen Thickness ◽  
Influence Of Temperature ◽  
Debye Waller Factor ◽  
Influence Of Temperature On ◽  
Atomic Form Factor

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).

The development of dormancy in bulblets of Lilium speciosum generated in vitro. II. The effect of temperature

1990 ◽  
Vol 80 (3) ◽  
pp. 431-436 ◽  
Author(s):  
Isabelle Delvallee ◽  
Annie Paffen ◽  
Geert-Jan De Klerk
Keyword(s):  
Effect Of Temperature ◽  
Lilium Speciosum

Effect of Temperature on ADP-Induced Platelet Aggregation

1973 ◽  
Vol 29 (01) ◽  
pp. 183-189
Author(s):  
C. A Praga ◽  
E. M Pogliani
Keyword(s):  
Platelet Aggregation ◽  
Incubation Period ◽  
Room Temperature ◽  
Important Variable ◽  
Practical Significance ◽  
Effect Of Temperature ◽  
Induce Platelet Aggregation ◽  
Cuvette Holder ◽  
Exact Temperature

SummaryTemperature represents a very important variable in ADP-induced platelet aggregation.When low doses of ADP ( < 1 (μM) are used to induce platelet aggregation, the length of the incubation period of PRP in the cuvette holder of the aggregometer, thermostatted at 37° C, is very critical. Samples of the same PRP previously kept at room temperature, were incubated for increasing periods of time in the cuvette of the aggregometer before adding ADP, and a significant decrease of aggregation, proportional to the length of incubation, was observed. Stirring of the PRP during the incubation period made these changes more evident.To measure the exact temperature of the PRP during incubation in the aggre- gometer, a thermocouple device was used. While the temperature of the cuvette holder was stable at 37° C, the PRP temperature itself increased exponentially, taking about ten minutes from the beginning of the incubation to reach the value of 37° C. The above results have a practical significance in the reproducibility of the platelet aggregation test in vitro and acquire particular value when the effect of inhibitors of ADP induced platelet aggregation is studied.Experiments carried out with three anti-aggregating agents (acetyl salicyclic acid, dipyridamole and metergoline) have shown that the incubation conditions which influence both the effect of the drugs on platelets and the ADP breakdown in plasma must be strictly controlled.

Effect of Temperature, Velocity Gradient and I.V. Heparin on in Vitro Blood Coagulation and Platelet Aggregation

1967 ◽  
Vol 17 (01/02) ◽  
pp. 112-119 ◽  
Author(s):  
L Dintenfass ◽  
M. C Rozenberg
Keyword(s):  
Blood Coagulation ◽  
Velocity Gradient ◽  
Elevated Temperatures ◽  
Morphological Changes ◽  
Effect Of Temperature ◽  
Clotting Time ◽  
Progressive Change ◽  
Aggregation Of Platelets ◽  
Microscopic Techniques

SummaryA study of blood coagulation was carried out by observing changes in the blood viscosity of blood coagulating in the cone-in-cone viscometer. The clots were investigated by microscopic techniques.Immediately after blood is obtained by venepuncture, viscosity of blood remains constant for a certain “latent” period. The duration of this period depends not only on the intrinsic properties of the blood sample, but also on temperature and rate of shear used during blood storage. An increase of temperature decreases the clotting time ; also, an increase in the rate of shear decreases the clotting time.It is confirmed that morphological changes take place in blood coagula as a function of the velocity gradient at which such coagulation takes place. There is a progressive change from the red clot to white thrombus as the rates of shear increase. Aggregation of platelets increases as the rate of shear increases.This pattern is maintained with changes of temperature, although aggregation of platelets appears to be increased at elevated temperatures.Intravenously added heparin affects the clotting time and the aggregation of platelets in in vitro coagulation.

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