Properties of Microfibers of Various Compositions as a Component of Cellular Composites

2021 ◽  
Vol 1040 ◽  
pp. 132-138
Author(s):  
Daria Dmitrievna Netsvet ◽  
Alexandr L. Popov ◽  
Viktoriya Viktorovna Nelubova ◽  
Svetlana V. Lasunova
Keyword(s):  
Weight Loss ◽  
Active Sites ◽  
Glass Fibers ◽  
Basalt Fiber ◽  
Alkali Resistance ◽  
Cement Matrix ◽  
Ambient Conditions ◽  
Model Medium ◽  
Adsorption Sites ◽  
High Durability

The paper presents studies on the properties of various types of micro-reinforcing fibers to assess their role and effectiveness in the structure formation of the cellular composite. Based on the data on the weight loss after exposure in a model medium of cement, analysis of the alkali resistance of fibers of five different types – basalt fiber, heat-treated basalt fiber, polymer fiber and glass fibers from two different manufacturers – was carried out. It is shown that the fibers have a sufficiently high durability in the medium of hardening cement, which is expressed by a relatively insignificant weight loss of the original fiber after exposure in a model medium for 28 days in ambient conditions. The weight loss for some fibers sharply increases when hardening conditions are changed to hydrothermal ones. The images of fibers exposed in a model medium of cement, obtained using scanning microscopy, were also analyzed, and the character of distribution of acidic and basic adsorption sites on the surface of fibers depending on the type was assessed. Based on the analysis of the obtained data, we can talk about a high number of active sites on the surface of basalt and glass fibers, which ensures the formation of crystalline new formations on them and makes it possible to predict their high adhesion to the cement matrix.

Effect of the Addition of ZrSiO4 on Alkali-Resistance and Liquidus Temperature of Basaltic Glass

2018 ◽  
Vol 766 ◽  
pp. 145-150
Author(s):  
Napaporn Vaiborisut ◽  
Chanittha Chunwises ◽  
Dararat Boonbundit ◽  
Sirithan Jiemsirilers ◽  
Apirat Theerapapvisetpong
Keyword(s):  
Liquidus Temperature ◽  
Glassy Phase ◽  
Glass Composition ◽  
Glass Fibers ◽  
Basalt Fiber ◽  
Alkali Resistance ◽  
Cement Matrix ◽  
X Ray Diffraction ◽  
Basalt Glass ◽  
Zirconium Silicate

Basalt fiber has been used as a reinforced material in cement-based materials because it has higher mechanical strength and cheaper than common silicate based glass-fibers. However, silicate-based glass fibers have low alkali resistance especially in cement matrix composite. In this work, we studied the improvement of alkali resistance by addition of zirconium silicate (ZrSiO4) in original basalt glass composition. The batch of basalt glass with additional ZrSiO4 contents of 0.00, 2.50, 5.00, 7.50 and 10.00 wt% were melted at 1500 °C. The liquidus temperature (TL) is important in for the fiber glass manufacturing. It need to formulate glass composition which requires a lower melting temperature and is crystallization resistant. TL as a function of composition is usually determined experimentally. In this study, glassy phase was determined by X-ray Diffraction (XRD). The glass transition temperature (Tg), the crystallization temperature (Tc) and TL were analyzed by Differential Thermal Analysis (DTA). The results found that the addition of ZrSiO4 in a basalt glass batch increased Tg while Tc of each sample was closed to original basalt fiber. Moreover, the alkali resistance of these glasses increased with an increasing of ZrSiO4 content. However, excessive ZrSiO4 contents (7.50 and 10.00 wt%) resulted in crystallization of ZrO2 which separated from glassy phase.

Modeling and experimental study on the mechanical behavior of glass/basalt fiber metal laminates after thermal cycling

2021 ◽  
pp. 105678952199873
Author(s):  
Mehdi Abdollahi Azghan ◽  
F Bahari-Sambran ◽  
Reza Eslami-Farsani
Keyword(s):  
Thermal Cycling ◽  
Glass Fibers ◽  
Basalt Fiber ◽  
Tensile Modulus ◽  
Alloy Sheet ◽  
Experimental Results ◽  
Weibull Function ◽  
Basalt Fibers ◽  
Thermal Stabilities ◽  
Fiber Metal

In the present study, the effect of thermal cycling and stacking sequence on the tensile behavior of fiber metal laminate (FML) composites containing glass and basalt fibers was investigated. To fabricate the FML samples, fibers reinforced epoxy composite were sandwiched between two layers of 2024-T3 aluminum alloy sheet. 55 thermal cycles were implemented at a temperature range of 25–115°C for 6 min. The tensile tests were carried out after the thermal cycling procedure, and the results were compared with non-thermal cycling specimens. Scanning electron microscopy (SEM) was employed for the characterization of the damage mechanisms. The FMLs containing four basalt fibers’ layers showed higher values of tensile strength, modulus, and energy absorption. On the other hand, the lowest strength and fracture energy were found in the asymmetrically stacked sample containing basalt and glass fibers, due to weak adhesion between composite components (basalt and glass fibers). The lowest tensile modulus was found in the sample containing glass fibers that was due to the low modulus of the glass fibers compared to basalt fibers. In the case of the samples exposed to thermal cycling, the highest and the lowest thermal stabilities were observed in basalt fibers samples and asymmetrically stacked samples, respectively. In accordance with the experimental results, a non-linear damage model using the Weibull function and tensile modulus was employed to predict the stress-strain relationship. The simulated strain–strain curves presented an appropriate agreement with the experimental results.

scholarly journals Synthesis of Valeric Acid by Selective Electrocatalytic Hydrogenation of Biomass-Derived Levulinic Acid

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 692
Author(s):  
Yan Du ◽  
Xiao Chen ◽  
Ji Qi ◽  
Pan Wang ◽  
Changhai Liang
Keyword(s):  
Levulinic Acid ◽  
Active Sites ◽  
Valeric Acid ◽  
Future Research ◽  
Adsorbed Hydrogen ◽  
Electrocatalytic Hydrogenation ◽  
Ambient Conditions ◽  
Metallic Lead ◽  
Faradaic Efficiency ◽  
Lead Electrode

The electrocatalytic hydrogenation (ECH) of biomass-derived levulinic acid (LA) is a promising strategy to synthetize fine chemicals under ambient conditions by replacing the thermocatalytic hydrogenation at high temperature and high pressure. Herein, various metallic electrodes were investigated in the ECH of LA in a H-type divided cell. The effects of potential, electrolyte concentration, reactant concentration, and temperature on catalytic performance and Faradaic efficiency were systematically explored. The high conversion of LA (93%) and excellent “apparent” selectivity to valeric acid (VA) (94%) with a Faradaic efficiency of 46% can be achieved over a metallic lead electrode in 0.5 M H2SO4 electrolyte containing 0.2 M LA at an applied voltage of −1.8 V (vs. Ag/AgCl) for 4 h. The combination of adsorbed LA and adsorbed hydrogen (Hads) on the surface of the metallic lead electrode is key to the formation of VA. Interestingly, the reaction performance did not change significantly after eight cycles, while the surface of the metallic lead cathode became rough, which may expose more active sites for the ECH of LA to VA. However, there was some degree of corrosion for the metallic lead cathode in this strong acid environment. Therefore, it is necessary to improve the leaching-resistance of the cathode for the ECH of LA in future research.

scholarly journals A Study of Mild Steel Corrosion UsingAdhatoda Vasica(AV) Extract as Inhibitor in Different Acid Medium

2010 ◽  
Vol 7 (4) ◽  
pp. 1284-1289 ◽  
Author(s):  
P. Matheswaran ◽  
A. K. Ramasamy
Keyword(s):  
Weight Loss ◽  
Mild Steel ◽  
Acid Medium ◽  
Acidic Medium ◽  
Active Sites ◽  
Mixed Type ◽  
Steel Corrosion ◽  
Adhatoda Vasica ◽  
Mild Steel Corrosion ◽  
Inhibitive Action

Corrosion behavior of mild steel in acidic medium usingAdhatoda Vasica(AV) extract was investigated. The inhibitive effective ofAdhatoda Vasicaon the corrosion of mild steel in different acidic medium has been studied by weight loss and polarization methods. The Ecorrvalues are shifted slightly towards negative side in presence of inhibitors which indicate the inhibitors inhibit the corrosion of mild steel in acids solution by controlling both anodic and cathodic reactions due to the blocking of active sites on the metal surface. It is evident that inhibitors bring about considerable polarization of the cathode as well as anode. It was, therefore, inferred that the inhibitive action is of mixed type.

scholarly journals Morphological and Elemental Investigations on Co–Fe–B–O Thin Films Deposited by Pulsed Laser Deposition for Alkaline Water Oxidation: Charge Exchange Efficiency as the Prevailing Factor in Comparison with the Adsorption Process

2021 ◽  
Author(s):  
Y. Popat ◽  
M. Orlandi ◽  
S. Gupta ◽  
N. Bazzanella ◽  
S. Pillai ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Water Oxidation ◽  
Active Sites ◽  
High Surface ◽  
Pulsed Laser ◽  
Industrial Applications ◽  
Active Species ◽  
Laser Deposition ◽  
Core Shell ◽  
Adsorption Sites

Abstract Mixed transition-metals oxide electrocatalysts have shown huge potential for electrochemical water oxidation due to their earth abundance, low cost and excellent electrocatalytic activity. Here we present Co–Fe–B–O coatings as oxygen evolution catalyst synthesized by Pulsed Laser Deposition (PLD) which provided flexibility to investigate the effect of morphology and structural transformation on the catalytic activity. As an unusual behaviour, nanomorphology of 3D-urchin-like particles assembled with crystallized CoFe2O4 nanowires, acquiring high surface area, displayed inferior performance as compared to core–shell particles with partially crystalline shell containing boron. The best electrochemical activity towards water oxidation in alkaline medium with an overpotential of 315 mV at 10 mA/cm2 along with a Tafel slope of 31.5 mV/dec was recorded with core–shell particle morphology. Systematic comparison with control samples highlighted the role of all the elements, with Co being the active element, boron prevents the complete oxidation of Co to form Co3+ active species (CoOOH), while Fe assists in reducing Co3+ to Co2+ so that these species are regenerated in the successive cycles. Thorough observation of results also indicates that the activity of the active sites play a dominating role in determining the performance of the electrocatalyst over the number of adsorption sites. The synthesized Co–Fe–B–O coatings displayed good stability and recyclability thereby showcasing potential for industrial applications. Graphic Abstract

The Selective Oxidation of Hydrocarbons on Isolated Iron Active Sites under Ambient Conditions

2019 ◽  
Vol 41 (6) ◽  
pp. 946-946
Author(s):  
Zhengliang Qi Zhengliang Qi ◽  
Junmei Liu Junmei Liu ◽  
Wanwan Guo and Jun Huang Wanwan Guo and Jun Huang
Keyword(s):  
Ionic Liquid ◽  
Activated Carbon ◽  
Carbon Material ◽  
Active Sites ◽  
High Selectivity ◽  
Good Activity ◽  
Ambient Conditions ◽  
Oxidation Of Hydrocarbons ◽  
Fe Catalysts ◽  
Iron Active Sites

The N-doped carbon material supported Fe catalysts were developed for the oxidation of C-H bond of hydrocarbons to ketones and alcohols. The supported Fe catalysts were prepared by pyrolysis of [CMIM]3Fe(CN)6 ionic liquid in activated carbon. And the Fe(Ⅲ)@CN-600 showed good activity and high selectivity for the oxidation of alfa C-H bond of alkylbenzenes. The isolated Fe(Ⅲ) iron active sites should be responsible for the high activity and selectivity for the oxidation of hydrocarbons to ketones. Several ketones were obtained in good to excellent yields. Moreover, cyclohexanone can also be obtained through the oxidation of cyclohexane.

scholarly journals Color change and quality response of ‘lane late’ orange submitted to degreening process

2015 ◽  
Vol 35 (1) ◽  
pp. 144-153 ◽  
Author(s):  
FRANCISCA L. DE C. MACHADO ◽  
JOÃO P. CAJAZEIRA ◽  
JOSÉ M. C. DA COSTA
Keyword(s):  
Weight Loss ◽  
Relative Humidity ◽  
Color Change ◽  
Titratable Acidity ◽  
High Relative Humidity ◽  
Soluble Solids ◽  
Ambient Conditions ◽  
Peel Color ◽  
Golden Yellow ◽  
Puncture Force

This study aimed at evaluating the effects of ethylene on peel color and compositional changes in ‘Lane late’ orange stored under refrigerated and ambient conditions. Physiologically mature, but green-peeled, oranges were exposed to ethylene gas under room temperature and high relative humidity for 24 hours. Storage chamber was ventilated with fresh air after 12 hours to mitigate consequences derived from fruit respiration. Both nondestructive analysis, such as peel color (hue angle, chromaticity, and brightness) and weight loss, and destructive ones (soluble solids, titratable acidity, pH, soluble solids to acidity ratio, and puncture force) were performed upon harvest, after degreening, and every three days during eighteen days in storage. Experiment was carried out using an entirely randomized design with thirty replications for nondestructive and four replications for destructive analyses, in a split plot scheme. Exposure to ethylene ensured a golden yellow peel for both fruit stored under ambient and refrigerated conditions. High relative humidity, associated with low temperature prevented fruit from losing moisture. Fruit exposure to ethylene did not affect weight loss, soluble solids, titratable acidity, pH, soluble solids, acidity ratio, or puncture force.

Basalt Fiber Reinforce Cement-Based Composite Materials

2011 ◽  
Vol 374-377 ◽  
pp. 1837-1842
Author(s):  
Ming Tang ◽  
Jing Qi Li ◽  
Hong Liang Liu ◽  
Ning Chen
Keyword(s):  
Composite Materials ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Basalt Fiber ◽  
Physical And Mechanical Properties ◽  
Alkali Resistance ◽  
Orthogonal Experimental Design ◽  
Enhancement Effect ◽  
Cement Ratio ◽  
Water Cement Ratio

In order to obtain the high performance cement-based consistent materials，the enhancement effect of basalt fiber was studied to develop the building mortar with a high flexural strength . Three factors such as basalt fibers fraction，water-cement ratio and sand-lime ratio are studied on compressive and flexural strength on 7 days and 28 days through the orthogonal experimental design and statistical analysis. According to project needs, the best combination of flexural strength is optimized. The enhancement mechanism and damage features are analyzed and evaluated by SEM, the result shows that the basalt fiber as enhanced component have a very good flexural strength enhancement effect, the maximum increased rate will reach 2.91 times. The effect on the strength of different age period is remarkable with different fiber fraction which is far greater than the water-cement ratio and sand-lime ratio. Basalt fiber have better physical and mechanical properties and better alkali resistance, some performance are second only to carbon fiber, and the cost of basalt fiber is far lower than carbon fiber, So the basalt fiber have a broad application prospects in the field of cement-based composite materials.

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