Elastic and structural properties of alkaline-calcium silica hydrogels

2005 ◽  
Vol 20 (2) ◽  
pp. 344-349 ◽  
Author(s):  
John W. Phair ◽  
Sergey N. Tkachev ◽  
Murli H. Manghnani ◽  
Richard A. Livingston
Keyword(s):  
Elastic Moduli ◽  
Network Formation ◽  
Brillouin Scattering ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Silica Hydrogels ◽  
Infrared Measurements ◽  
Alkaline Calcium

Brillouin scattering has been used to study the elastic properties of alkaline-calcium silica hydrogels synthesized from the precipitation of sodium silicate solution with calcium hydroxide. To the best of our knowledge, this is the first determination of the bulk elastic moduli for this type of alkaline-calcium silica hydrogel, also referred to as the alkali-silica reaction (ASR) gel. The measured bulk moduli for the alkaline-calcium silica hydrogels were found to be between 4 and 8 GPa for the gel containing 0.08 M Ca(OH)2 and between 10 and 25 GPa for the gel containing 0.8 M Ca(OH)2, increasing with increasing pressure. Fourier transform infrared measurements were made to correlate the moduli to the silica speciation and network formation within the gels as a function of Ca(OH)2 content. Significantly, for the concentrations considered, both the interconnection of the silica species and the bulk modulus increased with increasing Ca(OH)2 content. On this basis, Brillouin scattering was confirmed to be a useful method for distinguishing between the bulk moduli of alkaline-calcium silica hydrogels in terms of chemical composition. The potential for further characterization of ASR gels as a function of composition and water content by this technique is highly promising.

Extraction and Characterization of Silica Powders from Natural Waste for Environmental Remediation

2018 ◽  
Vol 934 ◽  
pp. 147-153
Author(s):  
Areeya Ti-Iatyor ◽  
Thawatchai Kongkue ◽  
Tawat Chanadee
Keyword(s):  
Environmental Remediation ◽  
Sodium Hydroxide Solution ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Waste Materials ◽  
Ft Ir ◽  
Groundnut Shell ◽  
Banana Leaves ◽  
Groundnut Shell Ash

The present work describes the preparation and characterization of silica powder from the natural waste materials stink bean pod, Barbados pride pod, banana leaves, coconut shell, sugar palm shell and groundnut shell. Ash was produced by incineration of the natural wastes at 650 °C for 1, 3 and 5 h in atmospheric air. Silica was then extracted from the natural waste ash using 1 M sodium hydroxide solution to produce a sodium silicate solution from which silica was precipitated by adding 5 M hydrochloric acid solution. The results showed that the low content of residual carbon from the natural waste was incinerated at the optimal condition of 650°C for 5 h. FT-IR indicated that the as-prepared silica had Si-O-Si and Si-OH functional groups consistent with the XRF analysis, which detected SiO2 content between 73.76 and 95.72 wt%. In analysis of XRD and SEM, the as-prepared silica exhibited an amorphous, irregular shape and particle sizes in a range from 1 to 2 μm. The results obtained by the reported method proved that natural waste materials can be used for the production of valuable silica.

Extended characterization of materials based on continuous instrumented indentation diagrams

2021 ◽  
Vol 2021 (3) ◽  
pp. 10-23
Author(s):  
B. A. Galanov ◽  
◽  
S. M. Ivanov ◽  
V. V. Kartuzov ◽  
◽  
...  
Keyword(s):  
Material Flow ◽  
Elastic Moduli ◽  
Contact Stiffness ◽  
Relative Size ◽  
Indentation Hardness ◽  
Instrumented Indentation ◽  
Characterization Of Materials ◽  
Instrumental Indentation

In addition to the traditional determination of hardness and elastic moduli from continuous diagrams of instrumental indentation, it is proposed to determine the yield stress, the characteristic of plasticity, the characteristic relative size of the elastoplastic zone under the indenter, and the volumetric deformation of the material in the area of contact of the indenter with the sample. The indentation diagram shows the transition point to the unconstrained material flow under the indenter. Keywords: indentation, hardness, elastic moduli, contact stiffness, elastic-plastic strains.

scholarly journals Micromechanical Characterization of Complex Polypropylene Morphologies by HarmoniX AFM

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
S. Liparoti ◽  
A. Sorrentino ◽  
V. Speranza
Keyword(s):  
Elastic Moduli ◽  
Force Microscopy ◽  
Atomic Force ◽  
Indentation Tests ◽  
Injection Molded ◽  
Micromechanical Characterization ◽  
Complex Polymer ◽  
Good Agreement

This paper examines the capability of the HarmoniX Atomic Force Microscopy (AFM) technique to draw accurate and reliable micromechanical characterization of complex polymer morphologies generally found in conventional thermoplastic polymers. To that purpose, injection molded polypropylene samples, containing representative morphologies, have been characterized by HarmoniX AFM. Mapping and distributions of mechanical properties of the samples surface are determined and analyzed. Effects of sample preparation and test conditions are also analyzed. Finally, the AFM determination of surface elastic moduli has been compared with that obtained by indentation tests, finding good agreement among the results.

scholarly journals Synthesis and characterization of mesoporous silica core-shell particles

2010 ◽  
Vol 4 (2) ◽  
pp. 81-85 ◽  
Author(s):  
Milan Nikolic ◽  
Konstantinos Giannakopoulos ◽  
Vladimir Srdic
Keyword(s):  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Silica Particles ◽  
Core Shell ◽  
Functionalized Silica ◽  
Silica Core ◽  
Shell Particles ◽  
Average Size ◽  
Core Particles

Core-shell particles were formed by deposition of primary silica particles synthesized from sodium silicate solution on functionalized silica core particles (having size of ~0.5 ?m) prepared by hydrolysis and condensation of tetraethylortosilicate. The obtained mesoporous shell has thickness of about 60 nm and consists of primary silica particles with average size of ~21 nm. Scanning electron microscopy and zeta potential measurements showed that continuous silica shell exists around functionalized core particles which was additionally proved by FTIR and TEM results.

scholarly journals Elastic Properties of a Polyimide Film Determined by Brillouin Scattering and Mechanical Techniques

1993 ◽  
Vol 308 ◽  
Author(s):  
R. Sai Kumar ◽  
Ivan K. Schuller ◽  
Sudha S. Kumar ◽  
A. Fartash ◽  
M. Grimsditch
Keyword(s):  
Elastic Properties ◽  
Brillouin Scattering ◽  
Direct Determination ◽  
Polyimide Film ◽  
Complete Characterization ◽  
Elastic Behavior ◽  
Complete Determination ◽  
Vibrating Membrane

ABSTRACTWe discuss here the complete determination of the elastic properties of a polyimide film using two experimental techniques. One technique employs the polymer film as a vibrating membrane and allows a direct determination of the ’macroscopic’ biaxial modulus. Brillouin scattering, which measures the elastic properties on a ∼ 100 μ scale, allows for a complete characterization of the elastic behavior. The results obtained by the two techniques are in agreement within the reported error bars.

scholarly journals Mechanical and microstructural characterization of geopolymer synthesized from low calcium fly ash

2015 ◽  
Vol 21 (1-1) ◽  
pp. 13-22 ◽  
Author(s):  
Sabina Kramar ◽  
Vilma Ducman
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Content ◽  
Sodium Silicate Solution ◽  
Microstructural Characterization ◽  
Silicate Solution ◽  
Low Calcium ◽  
Pore Size Distributions ◽  
Compressive Tests

This study deals with the mechanical and microstructural characterization of geopolymers synthesized from locally available fly ash. A low calcium fly ash was activated using a sodium silicate solution. Samples were characterized by means of flexural and compressive tests, Fourier Transform Infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). Porosity and pore size distributions were identified using mercury intrusion porosimetry and gas sorption. The compressive strength of the produced geopolymers, which is in the range of 1.6 to 53.3 N/mm2, is strongly related to the water content as well as SiO2/Na2O mass ratio of an alkali activator. The compressive strength significantly increased with decreases in the water content and increased silicon concentration used for the synthesis of geopolymers.

scholarly journals Synthesis and Characterization of Industrial Casting Sand Based Silica Aerogel

2021 ◽  
Vol 9 (12) ◽  
pp. 1254-1258
Author(s):  
Tuba Arkan
Keyword(s):  
Silica Aerogel ◽  
Ph Value ◽  
Sol Gel ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Chemical Components ◽  
Ft Ir ◽  
Casting Sand ◽  
Xrf Analyses

Abstract: In this study, a commercial foundry sand (Seydisehir Eti Aluminium Co. Inc.) was provided as the starting material. Using this supplied casting sand, silica aerogel production was carried out by sol-gel method. Starting materials chemical components were determined by doing XRD and XRF analyses to starting industrial casting sand respectively. After analysing studies, sodium silicate solution was produced from commercial casting sand. During silica aerogel synthesize, 5 different pH degree was investigated including 2-4-6-8 and 9. Silica aerogel modification (Super hydrophobic) was made by choosing the optimum pH value. Afer then, on the synthesized experiment sample, FT-IR, BET, SEM and contact angle characterization studies were realised respectively. As a result of preliminary experiments done with different pH experiments, sample with the lowest density was determined as pH 8 value. Keywords: Casting sand, Sol-gel, Silica aerogel

Mechanical Characterization of Apricena Marble by Ultrasonic Immersion Tests

2014 ◽  
Vol 628 ◽  
pp. 109-116 ◽  
Author(s):  
Anna Castellano ◽  
Pilade Foti ◽  
Aguinaldo Fraddosio ◽  
Salvatore Marzano ◽  
Mario Daniele Piccioni
Keyword(s):  
Wave Propagation ◽  
Elastic Moduli ◽  
Mechanical Characterization ◽  
Experimental Results ◽  
Elastic Response ◽  
Ultrasonic Velocities ◽  
Elastic Materials

We characterize the elastic response of Apricena marble by using advanced ultrasonic nondestructive techniques. An innovative experimental device for ultrasonic immersion tests is employed for the determination of ultrasonic velocities of waves travelling into the sample for any angle of propagation. The interpretation of the experimental results within the theoretical framework of wave propagation in elastic materials allows for both the classification of the anisotropy and the determination of the elastic moduli.

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