Preparation and Properties Study of Cementitious Grouts Containing Crumb Rubber

This article aims to improve the toughness of pre-packaged grouts (PPG) by incorporating crumb rubber. The mechanism for toughness of PPG with crumb rubber was analyzed based on the uniaxial compression model. Crumb rubber with surfaces treated by different methods (NaOH solutions or microwave treatment) was observed by scanning electron microscopy (SEM). The effects of mesh sizes, amounts, surface-treated methods of crumb rubber, and mixing procedures on the PPG’s mechanical strength and rheological properties were investigated. The results showed that, firstly, the addition of crumb rubber improves the PPG’s toughness, while its mechanical strength is reduced. Adding NaOH solutions or microwave-treated crumb rubber into PPG can weaken the negative effects of crumb rubber on the PPG’s mechanical strength; however, this function is limited. Secondly, the crumb rubber grouts’ rheological properties can be fully exploited by increasing the stirring rate and time so that the fluidity of crumb rubber grouts is improved, which fulfils the characteristics of no bleeding and micro-expansion. Finally, the optimal formula and mixing technique of crumb rubber grouts were proposed in this paper.The results of this paper can provide a significant reference for the application of scrap tires.

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Silica Microspheres for Economical Advanced Solar Applications

Crystals ◽

10.3390/cryst11111409 ◽

2021 ◽

Vol 11 (11) ◽

pp. 1409

Author(s):

Maha M. Khayyat

Keyword(s):

Electron Microscopy ◽

Mechanical Strength ◽

Rheological Properties ◽

Microwave Treatment ◽

Crumb Rubber ◽

Negative Effects ◽

Silica Microspheres ◽

Scrap Tires ◽

Scanning Electron ◽

Optimal Formula

This article aims to improve the toughness of pre-packaged grouts (PPG) by incorporating crumb rubber. The mechanism for toughness of PPG with crumb rubber was analyzed based on the uniaxial compression model. Crumb rubber with surfaces treated by different methods (NaOH solutions or microwave treatment) was observed by scanning electron microscopy (SEM). The effects of mesh sizes, amounts, surface-treated methods of crumb rubber, and mixing procedures on the PPG’s mechanical strength and rheological properties were investigated. The results showed that, firstly, the addition of crumb rubber improves the PPG’s toughness, while its mechanical strength is reduced. Adding NaOH solutions or microwave-treated crumb rubber into PPG can weaken the negative effects of crumb rubber on the PPG’s mechanical strength; however, this function is limited. Secondly, the crumb rubber grouts’ rheological properties can be fully exploited by increasing the stirring rate and time so that the fluidity of crumb rubber grouts is improved, which fulfils the characteristics of no bleeding and micro-expansion. Finally, the optimal formula and mixing technique of crumb rubber grouts were proposed in this paper. The results of this paper can provide a significant reference for the application of scrap tires.

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Influence of the Treatment Temperature on the Microstructure and Hydration Behavior of Thermoactivated Recycled Cement

Materials ◽

10.3390/ma13183937 ◽

2020 ◽

Vol 13 (18) ◽

pp. 3937

Author(s):

Sofia Real ◽

Ana Carriço ◽

José Alexandre Bogas ◽

Mafalda Guedes

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Mechanical Strength ◽

Water Demand ◽

Isothermal Calorimetry ◽

Setting Time ◽

Treatment Temperature ◽

Diffraction Field ◽

Resonance Spectroscopy ◽

Scanning Electron

This paper intends to contribute to a better knowledge of the production and rehydration of thermoactivated recycled cement and its incorporation in cement-based materials. To this end, the influence of the treatment temperature on the properties of recycled cements and recycled cement pastes was assessed by means of a wide array of tests. Anhydrous recycled cement as well as the resulting pastes were characterized through density and particle size, water demand and setting time, thermogravimetry, X-ray diffraction, field emission gun scanning electron microscopy, isothermal calorimetry, 29Si nuclear magnetic resonance spectroscopy, flowability, mechanical strength, mercury intrusion porosimetry and scanning electron microscopy. The treatment temperature had a significant influence on the dehydration and hydration of recycled cement, essentially resulting in the formation of C2S polymorphs of varying reactivity, which led to pastes of different fresh and hardened behaviors. The high water demand and the pre-hydration of recycled cement resulted in high setting times and low compressive strengths. The highest mechanical strength was obtained for a treatment temperature of 650 °C.

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The Study of Electroless Ni-B Coating on 45 Steel

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.501.185 ◽

2012 ◽

Vol 501 ◽

pp. 185-189

Author(s):

Jian Zhang Guo ◽

Qian Liu

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Corrosion Resistance ◽

Energy Dispersive Spectrometer ◽

Salt Spray ◽

High Hardness ◽

Experimental Results ◽

Electroless Ni ◽

Scanning Electron ◽

Optimal Formula

In order to improve the corrosion resistance and the hardness of the 45 steel, under comparison tests, the electroless Ni-B was prepared on the 45 steel. We made a contrast test to get the optimal formula. The coating under the optimal formula was characterized by Scanning Electron Microscopy(SEM), Energy Dispersive Spectrometer(EDS), metallurgical microscope and salt spray cabinet. The experimental results showed that the electroless Ni-B coating on 45 steel was low boron coating, with high hardness, and the hardness of the coating could catch HV524; the thickness of the coating was 16μm.

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Sodium alginate/cellulose nanocrystal fibers with enhanced mechanical strength prepared by wet spinning

Journal of Engineered Fibers and Fabrics ◽

10.1177/1558925019847553 ◽

2019 ◽

Vol 14 ◽

pp. 155892501984755

Author(s):

Jie Liu ◽

Rui Zhang ◽

Meiyu Ci ◽

Shuying Sui ◽

Ping Zhu

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Mechanical Strength ◽

Sodium Alginate ◽

Cellulose Nanocrystals ◽

Cellulose Nanocrystal ◽

Wet Spinning ◽

Transmission Electron ◽

Alginate Fibers ◽

Scanning Electron

Sodium alginate/cellulose nanocrystal fibers were prepared using a wet spinning method to enhance the mechanical strength of sodium alginate fibers. Cellulose nanocrystals were prepared by sulfuric acid hydrolysis method. The particle diameter size was measured, and the morphology of cellulose nanocrystals was characterized by transmission electron microscopy and scanning electron microscopy. The structure and mechanical properties of sodium alginate/cellulose nanocrystal fibers were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and mechanical strength testing. The incorporation of cellulose nanocrystals significantly improved the strength of alginate fibers because of the uniform distribution of cellulose nanocrystals in the alginate matrix. The tensile strength and elongation at break of the alginate fibers increased from 1.54 to 2.05 cN/dtex and from 8.29% to 15.05% with increasing cellulose nanocrystals content from 0 to 2 wt%, respectively.

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Pectin Extraction from Lemon By-product with Acidified Date Juice: Rheological Properties and Microstructure of Pure and Mixed Pectin Gels

Food Science and Technology International ◽

10.1177/1082013209353093 ◽

2010 ◽

Vol 16 (2) ◽

pp. 105-114 ◽

Cited By ~ 5

Author(s):

M. Masmoudi ◽

S. Besbes ◽

I. Ben Thabet ◽

C. Blecker ◽

H. Attia

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Rheological Properties ◽

Gel Formation ◽

Open Network ◽

Date Juice ◽

Pectin Gels ◽

Scanning Electron

The microstructure and the rheological properties of lemon-pectin mixtures were studied and compared to those of pure lemon (high methoxyl: HM) and date (low methoxyl: LM) pectins. Rheological properties were carried out in the presence of 30%, 45% and 60% sucrose, and increasing calcium concentrations (0-0.1%). The presence of date with lemon pectin led to a gel formation at 45% sucrose and in the presence of calcium, which was not the case for lemon pectin alone under the same conditions. It is suggested that lemon and date pectins interacted, leading to gel formations at different gelling temperatures, which were strongly dependant on degree of methylation. These results were confirmed by scanning electron microscopy, which revealed inhomogeneous gels where dense aggregated network and loose, open network areas were present. Addition of calcium to pectin mixture gels led to stronger and faster gel formation.

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Novel Methods to Manipulate Autolysis in Sparkling Wine: Effects on Yeast

Molecules ◽

10.3390/molecules26020387 ◽

2021 ◽

Vol 26 (2) ◽

pp. 387

Author(s):

Gail B. Gnoinski ◽

Simon A. Schmidt ◽

Dugald C. Close ◽

Karsten Goemann ◽

Terry L. Pinfold ◽

...

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Flow Cytometry ◽

Yeast Cell ◽

Microwave Treatment ◽

Control Flow ◽

Yeast Cells ◽

Sparkling Wine ◽

The Impact ◽

Scanning Electron

Sparkling wine made by the traditional method (Méthode Traditionelle) develops a distinct and desirable flavour and aroma profile attributed to proteolytic processes during prolonged ageing on lees. Microwave, ultrasound and addition of β-glucanase enzymes were applied to accelerate the disruption of Saccharomyces cerevisiae, and added to the tirage solution for secondary fermentation in traditional sparkling winemaking. Scanning electron microscopy and flow cytometry analyses were used to observe and describe yeast whole-cell anatomy, and cell integrity and structure via propidium iodide (PI) permeability after 6-, 12- and 18-months post-tirage. Treatments applied produced features on lees that were distinct from that of the untreated control yeast. Whilst control yeast displayed budding cells (growth features) with smooth, cavitated and flat external cell appearances; microwave treated yeast cells exhibited modifications like ‘doughnut’ shapes immediately after treatment (time 0). Similar ‘doughnut’-shaped and ‘pitted/porous’ cell features were observed on progressively older lees from the control. Flow cytometry was used to discriminate yeast populations; features consistent with cell disruption were observed in the microwave, ultrasound and enzyme treatments, as evidenced by up to 4-fold increase in PI signal in the microwave treatment. Forward and side scatter signals reflected changes in size and structure of yeast cells, in all treatments applied. When flow cytometry was interpreted alongside the scanning electron microscopy images, bimodal populations of yeast cells with low and high PI intensities were revealed and distinctive ‘doughnut’-shaped cell features observed in association with the microwave treatment only at tirage, that were not observed until 12 months wine ageing in older lees from the control. This work offers both a rapid approach to visualise alterations to yeast cell surfaces and a better understanding of the mechanisms of yeast lysis. Microwave, ultrasound or β-glucanase enzymes are tools that could potentially initiate the release of yeast cell compounds into wine. Further investigation into the impact of such treatments on the flavour and aroma profiles of the wines through sensory evaluation is warranted.

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Graphene as a stimulus for mechanical strength in glass-fiber reinforced polymers composite

World Journal of Engineering ◽

10.1108/wje-02-2021-0110 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Vijay Kumar Dwivedi ◽

Dipak Kumar

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Mechanical Strength ◽

Glass Fiber ◽

Fiber Reinforced Polymers ◽

Synthesis Process ◽

Fiber Reinforced ◽

Content Type ◽

Glass Fiber Reinforced ◽

Scanning Electron

Purpose The purpose of this paper is related with the comparative study between graphene-based glass fiber–reinforced polymer composites and without graphene composite on polymer matrix. The current study explains the result of amalgamation of 4 Wt.% graphene oxide (GO), in comparison to without graphene, on the mechanical strength of glass fiber/epoxy (GE). Design/methodology/approach A hand layup technique is used for the experimental study. For this, chemical synthesis process is approached based on Hummer’s theory. For mechanical testing of glass fiber–reinforced graphene composites and without graphene composites, American Society for Testing and Materials-3039 (ASTM3039) standards was adopted. Furthermore, comparatively, composites were characterized by field emission scanning electron microscopy. Findings Reinforcement of 4.0 Wt.% GO in epoxy matrix material showed 7.46% and 12.31% improvement in mechanical strength and elongation, respectively. Scanning electron microscopy results showed the influence of graphene cumulations in the failure of GO-reinforced GE (GO-GE) composites. Originality/value The inimitable things of graphene grounded nanofillers have encouraged in the world of material for their thinkable manipulation in glass fiber polymeric composites. In this work, for the first time, graphene is used as nanofiller in glass fiber epoxy coatings, and their fractography study is investigated.

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The morphology of the parasitic isopod Tachaea chinensis (Isopoda, Cymothoida) revealed through scanning electron microscopy and histological analysis

Crustaceana ◽

10.1163/15685403-bja10058 ◽

2021 ◽

Vol 94 (1) ◽

pp. 63-75

Author(s):

Xin Li ◽

Qijun Chen ◽

Yingdong Li

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Histological Analysis ◽

Body Cavity ◽

Future Research ◽

Negative Effects ◽

Internal Organs ◽

Parasitic Isopods ◽

Commercially Important ◽

Scanning Electron

Abstract Parasitic isopods have negative effects on several commercially important fishes and crustaceans. However, studies on these parasites, especially on their morphology, are limited. In the present study, scanning electron microscopy and simultaneous histological analysis were carried out to examine the external structure and composition of the internal organs of Tachaea chinensis (Isopoda, Corallanidae). Seven pairs of pereopods are sharp and hook-like, which are used for attaching to the host. Four pairs of the paddle-shaped pleopods indicate that it has the ability to swim freely. Analysis of the mouth appendages revealed that T. chinensis mainly feeds on the host’s blood. Moreover, we found numerous glands, including the salivary glands and hepatopancreas, in the coelom; loose connective tissue was also found in the ventral body cavity, which appeared to be a vestigial gonad. In addition, the description of the gland also provides valuable empirical data for future research.

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The effects of nanoclay on thermal, mechanical and rheological properties of LLDPE/chitosan blend

Journal of Polymer Engineering ◽

10.1515/polyeng-2015-0350 ◽

2017 ◽

Vol 37 (2) ◽

pp. 143-149 ◽

Cited By ~ 2

Author(s):

Sadullah Mir ◽

Bisma Asghar ◽

Abida K. Khan ◽

Rehana Rashid ◽

Ahson J. Shaikh ◽

...

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Tensile Strength ◽

Rheological Properties ◽

Loss Modulus ◽

Dynamic Shear ◽

Rheological Characterization ◽

Scanning Calorimetry ◽

High Dynamic ◽

Scanning Electron

Abstract The objective of this study was to prepare linear low density polyethylene (LLDPE)/chitosan/closite nanocomposites by using various concentrations of LLDPE, chitosan, and closite clay mineral. The nanocomposites were then characterized for their thermal, mechanical, and rheological properties by using different analytical techniques including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), rheological characterization, tensile strength study, and scanning electron microscopy. The TGA demonstrated that crosslinked composites are thermally more stable than non-crosslinked composites. The DSC stated that the percentage crystallinity of crosslinked composites is lower than the non-crosslinked composites. It is also observed that the increasing quantity of chitosan and closite also reduces the percentage crystallinity of the prepared nanocomposites. Rheological characterization revealed that, crosslinked composites are viscoelastic in nature and have high complex viscosities (η*) and high dynamic shear storage modulus (G′), while non-crosslinked composites showed high dynamic shear loss modulus (G″). Tensile strength of crosslinked composites was much higher than non-crosslinked composites, however elongation at break (Eb) values of non-crosslinked composites are higher than crosslinked composites. The scanning electron microscopy displayed strong adhesion between matrix-filler-interphase in crosslinked composites, while some gaps were also observed in non-crosslinked composites. As a conclusion, chitosan, closite clay, and the LLDPE based nanocomposites with improved thermal, mechanical, and rheological properties can be successfully prepared by employing a peroxide-initiated melt compounding technique.

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Mechanical strength of stainless steel and titanium alloy mini-implants with different diameters: an experimental laboratory study

Progress in Orthodontics ◽

10.1186/s40510-021-00352-w ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Sérgio Estelita Barros ◽

Viviane Vanz ◽

Kelly Chiqueto ◽

Guilherme Janson ◽

Eduardo Ferreira

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Stainless Steel ◽

Titanium Alloy ◽

Mechanical Strength ◽

Null Hypothesis ◽

Mini Implants ◽

The Mean ◽

Torsional Fracture ◽

Scanning Electron

Abstract Background The mechanical strength of mini-implants is a critical factor due to their small diameters. Currently, it is not possible to state whether there is a relevant difference between the mechanical properties of stainless steel (SS-MIs) and titanium alloy mini-implants (TA-MIs). The objective of this study was to test the null hypothesis that there is no difference in the mechanical strength of SS-MIs and TA-MIs, and to analyze, by scanning electron microscopy (SEM), the SS-MI, and TA-MI threads resistance to morphological damage after insertion. Methods A standardized sample of 504 SS-MIs and TA-MIs with diameters ranging from 1.2 mm to 1.8 mm was used. Torsional fracture was performed in 154 MIs. Flexural strength of 280 MIs was evaluated at 1 mm and 2 mm-deflection. The threads of 70 MIs were morphologically analyzed by scanning electron microscopy (SEM), before and after their insertion in high-density artificial bone blocks. Comparisons between SS-MIs and TA-MIs were performed with t tests or Mann-Whitney U tests. A multiple linear regression analysis was used to evaluate the influence of variables on the ranging of MI mechanical strength. Results SS-MIs had higher fracture torque. The mean difference between the SS-MIs and TA-MIs fracture torque was of 4.09 Ncm. The MI diameter explained 90.3% of the total variation in fracture torque, while only 2.2% was explained by the metallic alloy. The SS-MI group presented a higher deformation force during the 1mm and 2mm-deflection. The mean difference between the flexural strength of SS and TA-MIs at 1 mm and 2 mm-deflection was of 18.21 N and 17.55 N, respectively. There was no noticeable morphological damage to the threads of SS-MIs and TA-MIs. Conclusions The null hypothesis was rejected. SS-MIs were 13.2% and 20.2% more resistant to torsional fracture and deflection, respectively. The threads of the SS-MIs and TA-MIs were not damaged during the insertion and removal process. Thus, the use of SS-MI can reduce the fracture risk without increasing the MI diameter.

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