scholarly journals Elastic-viscous properties of acrylic acid 2-propenamide gel

2021 ◽  
pp. 79-88
Author(s):  
A.K. Dorosh ◽  
N.M. Bilko ◽  
D.I. Bilko
Keyword(s):  
Elastic Modulus ◽  
Acrylic Acid ◽  
Modulus Of Elasticity ◽  
Deformation Temperature ◽  
Complex Viscosity ◽  
Equilibrium Structure ◽  
Relative Deformation ◽  
Logarithmic Scale ◽  
Linear Scale ◽  
Biophysical Properties

The rheological properties of the gel-like material, the monomer of which is a crosslinked and modified 2-propenamide of acrylic acid, were determined by relaxation rheometry methods. The values of its elastic modulus and modulus of losses and complex viscosity depending on: deforming stress and its frequency are determined; relative deformation; temperature in the range (20-100) ° C and the regularities of these dependences are noted. It is established that: 1) the dependence of the modulus of elasticity (G'); modulus of loss (G'') and complex viscosity from: relative deformation; voltage; temperature; frequencies indicate that in the linear scale they change according to nonlinear dependencies, and in the transition to the logarithmic scale contain plateau-like areas; 2) analytical dependences of the above parameters on stress, strain rate and temperature are complex and difficult to establish; 3) in the range (20-80) ° C and relative deformations (10-100)% hydrogel has a virtually unchanged value of the modulus (G ') ten times greater than the modulus (G' '), whichdetermines the uniqueness of its rheological and biophysical properties ;  4) in the region (20-80) ° C hydrogel in terms of modulus of elasticity and tangent of the angle of loss is close to a completely elastic body; 5) when the frequency of the deforming voltage is more than 15.8 Hz and the relative deformation ≥100%, the gel is brittlely deformed; while the modulus of its elasticity decreases abruptly and the modulus of losses increases rapidly with increasing frequency of the deforming stress. 6) the dependence of the elastic-viscosity characteristics of the samples washed and unwashed in saline gel in the temperature range (20-80) ° C differ little and indicate that the equilibrium structure of the hydrogel 2-propenamide acrylic acid belongs to the typical colloidal dispersed structure of gelatinous substances.

Effect Of Elevated Temperatures On Complete Concrete Deformation Diagrams

2019 ◽  
pp. 9-14
Keyword(s):  
Experimental Data ◽  
Elastic Modulus ◽  
Elevated Temperatures ◽  
Peak Load ◽  
Relative Deformation ◽  
Deformation Characteristics ◽  
Compression Tests ◽  
Strain Behavior ◽  
Different Temperatures ◽  
Deformation Diagrams

The analysis of the previous results of the study on concrete stress-strain behavior at elevated temperatures has been carried out. Based on the analysis, the main reasons for strength retrogression and elastic modulus reduction of concrete have been identified. Despite a significant amount of research in this area, there is a large spread in experimental data received, both as a result of compression and tension. In addition, the deformation characteristics of concrete are insufficiently studied: the coefficient of transverse deformation, the limiting relative compression deformation corresponding to the peak load and the almost complete absence of studies of complete deformation diagrams at elevated temperatures. The two testing chambers provided creating the necessary temperature conditions for conducting studies under bending compression and tension have been developed. On the basis of the obtained experimental data of physical and mechanical characteristics of concrete at different temperatures under conditions of axial compression and tensile bending, conclusions about the nature of changes in strength and deformation characteristics have been drawn. Compression tests conducted following the method of concrete deformation complete curves provided obtaining diagrams not only at normal temperature, but also at elevated temperature. Based on the experimental results, dependences of changes in prism strength and elastic modulus as well as an equation for determining the relative deformation and stresses at elevated temperatures at all stages of concrete deterioration have been suggested.

scholarly journals Logarithmic Axis Graphs Distort Lay Judgment

2020 ◽  
Author(s):  
William Ryan ◽  
Ellen Riemke Katrien Evers
Keyword(s):  
Logarithmic Scale ◽  
Linear Scale ◽  
Policy Interventions ◽  
Linear Graphs

COVID-19 data is often presented using graphs with either a linear or logarithmic scale. Given the importance of this information, understanding how choice of scale changes interpretations is critical. To test this, we presented laypeople with the same data plotted using differing scales. We found that graphs with a logarithmic, as opposed to linear, scale resulted in laypeople making less accurate predictions of growth, viewing COVID-19 as less dangerous, and expressing both less support for policy interventions and less intention to take personal actions to combat COVID-19. Education reduces, but does not eliminate these effects. These results suggest that public communications should use logarithmic graphs only when necessary, and such graphs should be presented alongside education and linear graphs of the same data whenever possible.

Performance Deterioration of High Strength Concrete under Mixed Erosion and Freeze-Thaw Cycling

2010 ◽  
Vol 163-167 ◽  
pp. 1655-1660
Author(s):  
Jian Zhang ◽  
Bo Diao ◽  
Xiao Ning Zheng ◽  
Yan Dong Li
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Mass Loss ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
High Strength Concrete ◽  
High Strength ◽  
Freeze Thaw ◽  
Strength Concrete ◽  
Dynamic Modulus Of Elasticity

The mechanical properties of high strength concrete(HSC) were experimentally investigated under mixed erosion and freeze-thaw cycling according to ASTM C666(Procedure B), the erosion solution was mixed by weight of 3% sodium chloride and 5% sodium sulfate. The mass loss, relative dynamic modulus of elasticity, compressive strength, elastic modulus and other relative data were measured. The results showed that with the increasing number of freeze-thaw cycles, the surface scaled more seriously; the mass loss, compressive strength and elastic modulus continued to decrease; the relative dynamic modulus of elasticity increased slightly in the first 225 freeze-thaw cycles, then decreased in the following 75 cycles; the corresponding strain to peak stress decreased with the increase of freeze-thaw cycles. After 200 cycles, the rate of deterioration of concrete accelerated obviously.

scholarly journals Preparation and Preliminary Study on Irradiated and Thermally Treated Polypropylene (PP) - Styrene Butadiene Rubber (SBR) Composite

2011 ◽  
Vol 3 (3) ◽  
pp. 471-479
Author(s):  
M. S. I. Mozumder ◽  
M. M. Rahman ◽  
M. A. Rashid ◽  
M. A. Islam ◽  
M. E. Haque
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Radiation Dose ◽  
Aging Time ◽  
Modulus Of Elasticity ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Preliminary Study ◽  
Styrene Butadiene ◽  
Thermally Treated

The tensile strength (TS) and elastic modulus (ES) of non-irradiated (thermally treated) and irradiated Polypropylene (PP) - styrene butadiene rubber (SBR) composites were studied. The content of SBR (mass %) on PP and radiation dose play an important role on tensile strength and modulus of elasticity of PP-SBR composites. Tensile strength (TS) decreased markedly on increasing the SBR content on PP and even on exposing to radiation. The elastic modulus (EM) of PP-SBR composite has a tendency to increase with radiation dose and aging time but decreases with SBR loading. The water uptakes increase with SBR loading which accelerate with aging.Keywords: Polypropylene; Styrene butadiene rubber; Tensile strength; Elastic modulus.© 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi:10.3329/jsr.v3i3.3288               J. Sci. Res. 3 (3), 481-489 (2011)

Influences of Scarf-Joint of the Laminae in the Strength and Elasticity of Glued Laminated Timber Beams

2017 ◽  
Vol 864 ◽  
pp. 336-340 ◽  
Author(s):  
E.V.M. Carrasco ◽  
J.N.R. Mantilla ◽  
M.A. Smits ◽  
V.D. Pizzol ◽  
P.V. Krüger ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Linear Regression ◽  
Modulus Of Elasticity ◽  
Effective Elastic Modulus ◽  
Araucaria Angustifolia ◽  
Timber Beam ◽  
Glued Laminated Timber ◽  
Scarf Joint ◽  
Timber Beams

The objective of this work is to determinate the influence of the scarf-jointed in the strength and the modulus of elasticity of the glued laminated timber beam. To determine this influence, several tests with the outer laminae with scarf-joint and the bevel with different inclinations has been made. The models were made of Parana Pine, Araucaria angustifolia. For the tests were performed three points bending. With the load values and the deflection at mid-span and by linear regression were determined the effective elastic modulus. The results indicate that the performance is reduced considerably in the presence of a scarf-joint in the external laminae and also the reduction is greater when the scarf angle increases.

Production of mullite‒TiC‒с-BN‒с-ZrO2-materials by the method of plasma-spark sintering and their properties

2019 ◽  
pp. 23-29 ◽  
Author(s):  
A. V. Hmelov
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Elastic Modulus ◽  
Linear Correlation ◽  
Modulus Of Elasticity ◽  
Physical And Mechanical Properties ◽  
Linear Shrinkage ◽  
Physicomechanical Properties ◽  
Intensive Development ◽  
Crystalline Microstructure

The effect of different с-BN and с-ZrO2 ratios on the phase composition, microstructure, relative density, open porosity, linear shrinkage, physicomechanical properties, and linear correlation of the elastic modulus and toughness of samples during plasma-spark sintering at pressing load 70 MPa in the range of 1200‒1600 °C is shown. The synthesized powders of TiC, c-BN and c-ZrO2, sintered at 1400 °C by the plasma-spark method, are characterized by intense crystallization of the phases. Sintered samples with different ratios of c-BN and c-ZrO2 show the intensive development of mullite and TiC. An increase in the c-BN / c-ZrO2 ratio promotes an active increase in c-BN and a less intensive increase in с-ZrO2 in the range of 1200‒1600 °C, and it causes the formation of a less uniform and densely sintered crystalline microstructure with a large number of pores at 1500 °C. This sample has lower values of physical and mechanical properties and a lower linear correlation of the modulus of elasticity and toughness in the range of 1200‒1600 °C and lower crack resistance at 1500 °C. Ill. 9. Ref. 13. Tab. 1.

Influence of Aggregates on the Strength and Elastic Modulus of High Strength Mortars Containing Microsilica

1984 ◽  
Vol 42 ◽  
Author(s):  
E. Dingsøyr ◽  
T. Mosberg ◽  
J. F. Young
Keyword(s):  
Elastic Modulus ◽  
Modulus Of Elasticity ◽  
High Strength ◽  
Strength Development ◽  
Aggregate Model ◽  
Electron Microscopic ◽  
Bond Failure ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

AbstractThe strength development of mortars made with a high strength paste containing microsilica was investigated as a function of aggregate type and content. Strength could be modelled using composite theory; the predicted strengths of the paste and aggregate component reflected the influence of the cement-aggregate bond. Scanning electron microscopic examinations gave a qualitative idea of the extent of bond failure, which correlated satisfactorily with the predicted behavior. The modulus of elasticity for SiC mortars could be predicted well by Hirsch's model or the aggregate model.

NANOINDENTATION STUDY OF NANOCRYSTALLINE NICKEL

2005 ◽  
Vol 04 (02) ◽  
pp. 197-205 ◽  
Author(s):  
R. JAYAGANTHAN ◽  
K. MOHANKUMAR ◽  
A. A. O. TAY
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Grain Boundary ◽  
Modulus Of Elasticity ◽  
Loading Rate ◽  
Defect Density ◽  
Rate Sensitivity ◽  
Load Rate ◽  
Loading And Unloading ◽  
Force Displacement

The mechanical properties of nanocrystalline (Nc) Ni (electrodeposited, sintered, rolled) and microcrystalline (Mc) Ni were investigated by nanoindentation technique. Force-displacement curves generated during loading and unloading of the nanoindenter tip (Berkovich diamond tip) were used to determine the hardness and elastic properties of the Nc-nickel. The influence of loading rate on the hardness of electrodeposited Nc- Ni and microcrystalline (Mc) Ni were studied in the present work. The electrodeposited Nc-nickel exhibits higher hardness and elastic modulus when compared to sintered Nc-nickel. The higher modulus of elasticity is observed for the rolled Nc-nickel due to the increased defect density and less porosity in the samples. The higher modulus of elasticity is observed for Mc-nickel when compared to that of Nc-nickel (electrodeposited) with varying load rate. The strain rate sensitivity of Nc-nickel is due to the grain boundary affected zone.

Repeatability and Reproducibility of the Static Elastic Modulus of Concrete Measurement

2018 ◽  
Vol 272 ◽  
pp. 214-219
Author(s):  
Petr Misák ◽  
Tomáš Vymazal ◽  
Dalibor Kocáb ◽  
Barbara Kucharczyková
Keyword(s):  
Elastic Modulus ◽  
Statistical Methods ◽  
Modulus Of Elasticity ◽  
Interlaboratory Comparison ◽  
Hardened Concrete ◽  
Test Results ◽  
Static Modulus ◽  
Repeatability And Reproducibility ◽  
Expected Values ◽  
Static Modulus Of Elasticity

In recent years, the static modulus of elasticity is one of the most discussed property of hardened concrete. The aim of this article is to show results of 6 performed experiments focused on test results precision. The measurements were made according to the standards ISO 6784 and ISO 1920-10. More than 20 participants (laboratories) from Europe took part in these experiments. Test results were compared using the statistical methods for interlaboratory comparison. Repeatability and reproducibility, which provide more detailed information about range of expected values of elastic modulus, are the most discussed characteristics in the article.

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