Viscometric Studies of Rubber Solutions

1935 ◽  
Vol 8 (2) ◽  
pp. 259-265 ◽  
Author(s):  
Markus Reiner
Keyword(s):  
Inflection Point ◽  
Rotational Diffusion ◽  
Viscosity Measurement ◽  
Stress Axis ◽  
Convex Part ◽  
Cent Concentration ◽  
Straight Line ◽  
Newtonian Liquids ◽  
Consistency Curve ◽  
Newtonian Behavior

Abstract A former communication reported viscometric observations on rubber-toluene solutions in different capillary and rotation viscometers. The consistency curve of solutions from 0.08 to 1.77 per cent concentration starts at the origin as a straight line, inclined at a definite angle until it reaches a certain point a (see Fig. 1). From there it becomes convex toward the stress axis. This convex part extends to an inflection point b where the curve becomes concave up to a point c, where it again becomes a straight line which by extrapolation passes through the origin. The solutions therefore behave as Newtonian liquids between points o and a, and c and ∞. Between point a and c they are non-Newtonian liquids. It was furthermore shown that the “relative” consistency curve, i. e., a curve in which the shearing stress is reduced or the rate of shear increased in proportion to the viscosity of the solvent, is independent of the temperature at which the viscosity measurement is made. From this latter property the conclusion was drawn that the phenomenon of non-Newtonian behavior is a purely mechanical one. It cannot be due, as has been suggested by Staudinger, to a competition between orientation due to laminar flow and rotational diffusion due to Brownian movement because the magnitude of the latter depends on the temperature.

Viscosity Measurement Technique Using Standard Glass Burette for Newtonian Liquids

2005 ◽  
Vol 33 (1) ◽  
pp. 101-125 ◽  
Author(s):  
C. Igathinathane ◽  
V. K. Malleswar ◽  
U. Appa Rao ◽  
L. O. Pordesimo ◽  
A. R. Womac
Keyword(s):  
Measurement Technique ◽  
Viscosity Measurement ◽  
Standard Glass ◽  
Newtonian Liquids

The programm for highlighting the main components resulting in the algebraic model of constructive logic

10.12737/5612 ◽  
2014 ◽  
Vol 8 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Хромушин ◽  
Viktor Khromushin ◽  
Хромушин ◽  
Oleg Khromushin
Keyword(s):  
Mathematical Model ◽  
Inflection Point ◽  
Detection Limits ◽  
Algebraic Model ◽  
Constructive Logic ◽  
Straight Line ◽  
Nonlinear Mathematical Models ◽  
Main Components ◽  
Combined Mark

The article presents the program to determine the principal components resulting in the algebraic model of constructive logic, which is designed for construction multivariate nonlinear mathematical models. The resulting mathematical model is represented by a set of resulting components as factors indicating the detection limits, combined mark of conjunction (indicating joint impact). Each resulting component is characterized by power, which is the essence of the number of rows in the table that match the specified detection limits factors in their joint action. The program provides two methods to determine the main result components. The first method is based on determining the minimum difference between increasing amounts of capacity resulting components of the top and bottom. The second method is based on the determination of the inflection point of the curve decreasing capacity of the resulting components. The authors give recommendations on the choice of allocation method the main result components. If the curve changes power has a dedicated point of inflection and more like a straight line, it is recommended to use method 1. If the curve changes power has a dedicated point of inflection, it is recommended to use method 2. The program should be used in the package of analytical programs algebraic model of constructive logic when performing complex analytical calculations in biophysics, medicine and biology.

scholarly journals Effect of a Non-Newtonian Load on SignatureS2for Quartz Crystal Microbalance Measurements

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Jae-Hyeok Choi ◽  
Kay K. Kanazawa ◽  
Nam-Joon Cho
Keyword(s):  
Quartz Crystal Microbalance ◽  
Quartz Crystal ◽  
Volume Concentration ◽  
Interfacial Interaction ◽  
Quartz Resonator ◽  
Measurement Analysis ◽  
Wide Range ◽  
Experimental Subjects ◽  
Newtonian Liquids ◽  
Newtonian Behavior

The quartz crystal microbalance (QCM) is increasingly used for monitoring the interfacial interaction between surfaces and macromolecules such as biomaterials, polymers, and metals. Recent QCM applications deal with several types of liquids with various viscous macromolecule compounds, which behave differently from Newtonian liquids. To properly monitor such interactions, it is crucial to understand the influence of the non-Newtonian fluid on the QCM measurement response. As a quantitative indicator of non-Newtonian behavior, we used the quartz resonator signature,S2, of the QCM measurement response, which has a consistent value for Newtonian fluids. We then modified De Kee’s non-Newtonian three-parameter model to apply it to our prediction ofS2values for non-Newtonian liquids. As a model, we chose polyethylene glycol (PEG400) with the titration of its volume concentration in deionized water. As the volume concentration of PEG400 increased, theS2value decreased, confirming that the modified De Kee’s three-parameter model can predict the change inS2value. Collectively, the findings presented herein enable the application of the quartz resonator signature,S2, to verify QCM measurement analysis in relation to a wide range of experimental subjects that may exhibit non-Newtonian behavior, including polymers and biomaterials.

Viscosity (Part 1)

1981 ◽  
Vol 14 (3) ◽  
pp. 73-78 ◽  
Author(s):  
D. C-H. Cheng
Keyword(s):  
Apparent Viscosity ◽  
Absolute Measurement ◽  
Viscosity Measurement ◽  
Newtonian Fluids ◽  
Current Work ◽  
Practical Implementation ◽  
Newtonian Viscosity ◽  
Know How ◽  
The Subject ◽  
Newtonian Liquids

This article reviews the standard specifications related to viscosity measurement, issued by ASTM, BSI, IP and other standard bodies, and their applications. The know-how embodied in these specifications is discussed in relation to knowledge recorded in the literature and some aspects of practical implementation and use are considered. It is shown that standards and calibration are well established for Newtonian liquids and viscosity measurement can be accurate and precise. But, for non-Newtonian fluids, the specifications give apparent viscosity, not absolute values; and even then the results, although they can be precise, are of uncertain accuracy. It is pointed out that information exists in the literature on the subject of absolute measurement of non-Newtonian viscosity but that it needs to be simplified and codified before it can be incorporated into standard specifications. Current work towards this end is referred to.

Extensive small cell lung cancer (SCLC) chemotherapy: A population kinetics assessment.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e21101-e21101
Author(s):  
David J. Stewart ◽  
Stephanie Yasmin Brule
Keyword(s):  
Induction Therapy ◽  
Half Life ◽  
Inflection Point ◽  
Small Cell Lung ◽  
Maintenance Strategies ◽  
Convex Curves ◽  
Line Therapy ◽  
Straight Line ◽  
Log Linear

e21101 Background: Most progression-free (PFS) and overall survival (OS) curves fit exponential decay models on nonlinear regression analysis (NLRA). Log-linear curve shape varies with tumor & therapy type: straight line vs inflection to right (2 phase decay due to 2 distinct subpopulations with differing sensitivities) vs convex (downward inflection, eg due to stopping therapy that is slowing tumor growth).1 We compared SCLC to other cancers. Methods: As previously described,1 we did NLRA of published PFS & OS curves for etoposide-platinum in SCLC. We also assessed various therapies in other cancers. We calculated PFS & OS half-lives and classified curves by log-linear shape. Results: Of 18 evaluable SCLC PFS curves, 14 (78%) were highly convex & 18 (100%) were moderately or highly convex, compared to 35/888 (4%) highly convex & 186 (21%) moderately or high convex curves for other cancers (p < 0.0001). Of 24 evaluable SCLC OS curves, 12 (50%) were highly convex & 24 (100%) were moderately or highly convex, compared to 15/363 (4%) being highly convex & 87 (24%) moderately or highly convex for other cancers (p < 0.0001). In SCLC, 6 vs 4 cycles induction therapy minimally changed PFS half-life (median across studies 5.5 vs 5.2 months, p = 0.27) or OS half-life (9.5 vs 10.4 months, p = 0.06). PFS half-life correlated with OS half-life for other cancers (n 320, Spearman r 0.81, p < 0.0001) but not for SCLC (n 18, r 0.04, p = 0.86). Post progression survival (PPS) correlated positively with PFS half-life for other cancers (n 376, r 0.68, p < 0.0001) but correlated negatively for SCLC (n 18, r -0.43, p = 0.07). SCLC PFS curves had an initial downward inflection at a median of 2.9 months (where 87% of patients are still progression-free), followed by a 2nd inflection point at 4.5 months (where 71% are still progression-free). Median PFS half-life was 14.6 months prior to the 1st inflection point vs 1.9 months after the 2nd inflection point. Our analysis methods1 suggest that after the 2nd PFS inflection point, 23% of patients would progress by the next scan if scans are done every 3 weeks, while 40% would progress by the next scan if they are done every 6 weeks. Conclusions: PFS & OS curves for SCLC are more often highly convex than for other cancers since SCLC is sensitive to chemotherapy but progresses rapidly after induction therapy is completed. Giving 6 rather than 4 induction cycles makes no OS difference. New maintenance strategies are needed. Very short PFS half-lives post induction suggest that frequent follow up scans should be done for patients who are candidates for 2nd line therapy. 1. Stewart. Cancer Med 2019; 8:6871

The straight‐slope method for basement depth determination revisited

Geophysics ◽  
1993 ◽  
Vol 58 (4) ◽  
pp. 593-595 ◽  
Author(s):  
Jan Reidar Skilbrei
Keyword(s):  
Magnetic Anomaly ◽  
Inflection Point ◽  
Horizontal Projection ◽  
Slope Method ◽  
Source Estimation ◽  
Magnetic Source ◽  
Straight Line ◽  
Depth Determination ◽  
Basement Depth ◽  
General Reliability

The straight‐slope method is still popular for depth to magnetic source estimation due to its simplicity and general reliability in manual interpretation (e.g., Nettleton, 1976). Other commonly used manual slope methods are Peters rule (Peters, 1949) and Sokolov rule (Åm, 1972). The straight‐slope method uses the horizontal projection of the straightline part of the magnetic anomaly curve at the inflection point as the depth estimator (see Figure 1). Because no straight line exists mathematically, the rule is purely empirical, even though visually a certain part of a curve will appear to be straight.

scholarly journals Evaluation of different methods to identify preconsolidatin pressure of Champlain Sea Clay from CRS tests

2021 ◽  
Author(s):  
Andries Kirstein
Keyword(s):  
Numerical Methods ◽  
Test Data ◽  
Inflection Point ◽  
Ease Of Use ◽  
Graphical Methods ◽  
Identification Methods ◽  
Straight Line ◽  
Preconsolidation Pressure ◽  
Constant Rate ◽  
Geotechnical Problems

Identifying precisely the preconsolidation pressure of any soil is one of the most challenging geotechnical problems. For sensitive soils, misjudging the preconsolidation pressure can lead to a large overestimation or underestimation of settlement due to the high compressibility after p’c. The performances of eleven graphical identification methods are evaluated on constant rate of strain (CRS) consolidation tests conducted on Champlain Sea clay. The tests include unloading/reloading cycles that are used to evaluate the accuracy of the methods based on known maximum past pressure. A number of numerical procedures are developed to aid in the use of the graphical methods for CRS test data, including locating the inflection point and the point of the maximum curvature on an e-logp curve. Preconsolidation pressure is calculated using straight line equations rather than interpreting it visually. These numerical methods are applied to the test data and their validities and ease of use are evaluated.

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