•Application of nanosilica or microsilica increased the compressive strength of AAS concrete.•Application of microsilica decreased the short-term and total water absorption of AAS ...concrete.•Application of nanosilica led to increase in measured water penetration depths.•Microsilica has a positive effect and nanosilica has a negative effect on Carbonation resistance.•Application of nanosilica in AAS concrete mix leads to Tilleyite formation with negative effects.
The reliability and durability of concrete are issues which often draw marginal attention and are partially overshadowed by other performance factors, in particular the compressive strength of concrete. However, properties such as permeability and microstructural features of concrete matrix and the arrangement of its pores are known to have significant effects on concrete durability. Considering the adverse environmental impacts of cement production, the use of alkali activated slag concrete can be considered as a more environmentally friendly approach to concreting. This study investigated the effect of partial replacement of the slag used in alkali activated slag concrete with nanosilica and microsilica on its permeability. The effect of nanosilica and microsilica, both individually and in combination, on permeability of alkali activated slag concrete was examined through water impermeability test, rapid chloride permeability test, carbonation test, short-term and total water absorption tests, and compressive strength test. In addition, changes in paste microstructure were examined by Scanning Electron Microscopy (SEM) and X-ray Diffraction analysis. The results showed that partial replacement of slag with nanosilica has some effect on microstructure of the paste, leading to undesirable results in regard with permeability; however the use of microsilica improved permeability.
•Steel surface was treated by Ce and acid phosphoric solutions.•Ce treatment considerably enhanced the surface energy and produce nanoscale roughness.•Ce treated samples showed enhanced adhesion to ...FBE coating.•Ce treatment of steel significantly reduced the FBE cathodic delamination rate.•Ce treated sample showed enhanced corrosion resistance.
The effect of surface pre-treatment of pipe surface by green cerium compound and phosphoric acid solution on the fusion-bonded epoxy (FBE) coating performance was studied. The composition and surface morphology of the steel samples treated by acid and Ce solutions were characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), equipped with energy dispersive spectroscopy (EDS). Also, the surface free energy was evaluated on these samples through contact angle measurements. In addition, the effect of Ce and acid washing procedures on the adhesion properties and corrosion protection performance of the FBE was examined by pull-off, salt spray and electrochemical impedance spectroscopy (EIS) tests. Results showed that compared to acid washing, the chemical treatment by Ce solution noticeably increased the surface free energy of steel, improved the adhesion properties of FBE, decreased the cathodic delamination rate of FBE, and enhanced the coating corrosion resistance compared to the acid washed samples.
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•Surface of ZnO nanoparticles was treated with different silane coupling agents.•Amino- and glycidoxy-functional silane modifiers (at three concentration levels) were used.•The ...modified particles were incorporated in the epoxy matrix and exposed to QUV chamber.•The weathering performance was studied using different surface techniques.•Results approved the considerable weathering improvement of the filled epoxy.
This paper aims at improving the weathering performance of an epoxy coating via surface treatment of zinc oxide (ZnO) nanoparticles with different silane coupling agents. The main target of treatment is to suppress the photocatalytic activity of ZnO nanoparticles during weathering exposure. Amino- and glycidoxy-functional silane coupling agents (at three concentration levels) were used for this purpose. The positive influence of such treatment on the weathering performance was approved using different (aesthetic, mechanical, chemical, and topological) techniques. The color change variations results exhibited that ΔE decreased to half (from 6.5 for unfilled to 3.3 for the ZG 1.5-filled coating after 450 h accelerated weathering) in the presence of both modified nanoparticles, especially those treated with glycidoxy silane. FTIR results also approved that carbonyl index, which has increased around 83 % upon weathering for Neat epoxy, varied only 18 % in the presence of glycidoxy-modified ZnO. It was also revealed that modification with the stoichiometric or higher (1.5 stoichiometric) level of silane coupling agents was more effective in such improvement.
•Corrosion inhibitive pigment based on ZnOCo was synthesized through combustion method.•Doping ZnO nanoparticle with Co enhanced its inhibition properties considerably.•ZnOCo nanoparticle could ...enhance corrosion protective performance of epoxy coating.•Co doped ZnO nanoparticles behaved as efficient barrier and inhibitive pigment.
Co doped ZnO nanoparticles were synthesized by combustion method. Then, the epoxy nanocomposites were prepared using various amounts of nanoparticles. Salt spray and electrochemical impedance spectroscopy (EIS) were used in order to investigate the corrosion inhibition effects of nanoparticles on the steel substrate. The morphology and composition of the films precipitated on the steel surface were investigated by scanning electron microscope (SEM) and energy dispersive spectroscopy. Results revealed that the corrosion inhibition properties of ZnO nanoparticle were significantly enhanced after doping with Co. Moreover, Co doped ZnO nanoparticles enhanced the corrosion resistance of the epoxy coating effectively.
•Aluminum nanoparticle was modified with amino trimethylene phosphonic acid.•2wt% of zinc dust in zinc-rich paint was substituted by aluminum nanoparticles.•Surface modified aluminum nanoparticle ...improved the cathodic period of protection.•Aluminum nanoparticles enhanced the corrosion protection of the zinc-rich coating.
Aluminum nanoparticle was modified with amino trimethylene phosphonic acid (ATMP). The surface characterization of the nanoparticles was done by X-ray photo electron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis. The influence of the replacement of 2wt% of zinc dust in the standard zinc-rich epoxy coating by nanoparticles on the electrochemical action of the coating was studied by electrochemical impedance spectroscopy (EIS) and salt spray tests. The morphology and phase composition of the zinc rich paints were evaluated by X-ray diffraction (XRD) and filed-emission scanning electron microscopy (FE-SEM). Results showed that the ATMP molecules successfully adsorbed on the surface of Al nanoparticles. Results obtained from salt spray and electrochemical measurements revealed that the addition of surface modified nanoparticles to the zinc rich coating enhanced its galvanic action and corrosion protection properties.
Higher risk of fracture reported in individuals with autism spectrum disorder (ASD) might be linked to poor bone health and development in childhood. This study aimed to systematically review studies ...comparing imaged bone outcomes between children with ASD and typically developing children (TDC) or reference data, and to perform a meta-analysis comparing commonly reported bone outcomes. We searched articles published since August 2020 from PubMed, Cochrane Library, Web of Science, EMBASE, and Scopus databases. We included studies comparing areal bone mineral density (aBMD) between children with ASD and TDC in the qualitative analysis (meta-analysis), and evaluated other imaged bone outcomes qualitatively. Seven publications were identified for the systematic review, and four studies were included in the meta-analysis. The meta-analysis indicated lower aBMD at the total body (standardized mean difference = − 0.77; 95% CI, − 1.26 to − 0.28), lumbar spine (− 0.69; − 1.00 to − 0.39), total hip (− 1.00; − 1.82 to − 0.17), and femoral neck (− 1.07; − 1.54 to − 0.60) in children with ASD compared to TDC. Based on our qualitative review, limited evidence suggested 13% lower bone mineral content at the total body and 10–20% lower cortical area, cortical and trabecular thickness, and bone strength at the distal radius and tibia in children with ASD. Children with ASD have lower aBMD at the total body, lumbar spine, and hip and femoral neck compared to TDC. Limited evidence also suggests deficits in bone mineral content, micro-architecture, and strength in children with ASD.
•Non-uniform magnetic field effects on melting & solidification of NEPCM investigated.•Electrical conductivity has negative impact on solidification & melting process time.•Impact of FHD of ...non-electrical conductive ferrofluid in melting process is high.•Increasing magnetic number accelerates the solidification process.•An increase in Hartman number slows solidification process down.
In this study, the effects of non-uniform magnetic fields on melting and solidification of Nanoparticle-Enhanced Phase Change Materials (NEPCM) in an annulus enclosure are numerically investigated. Magnetic fields are applied on electrically conductive magnetic nanofluids by positioning a wire carrying the electric current in the center of the annulus. For the numerical simulation, a homogenous single-phase model and finite volume method are used and the melting and solidification processes are studied using the enthalpy-porosity method, where, instead of explicitly tracking the liquid-solid interface, the so-called liquid fraction quantity is computed based on the enthalpy balance in each cell and in each time iteration. The results show that, for the case with non-electrical conductive magnetic nanofluids, by increasing the magnetic number, the time required for the melting and solidification processes are reduced up to 39.91% and 14.29%, respectively. However, for the case with electrical conductive magnetic nanofluids at Ra = 104 and at specific magnetic numbers, the rate of both melting and solidification processes decreases by increasing the Hartmann number.
This research presents the modification of ZnO nanoparticles by Glycidoxypropyltrimethoxysilane (GPTMS) to produce hybrid nanostructured additives to improve the weathering resistance of epoxy ...silicone coatings. The modified ZnO nanoparticles were incorporated into epoxy silicone coatings at different loading dosages. The coatings were then weathered in an accelerated weathering chamber and removed after specific intervals (0, 500, and 1000 h) for further characterization. The effect of different loadings of modified ZnO nanoparticles (0.1, 0.5, and 1 wt%) on the weathering resistance of epoxy silicone coatings was studied using SEM, AFM, FTIR, and contact angle measurement, UV–visible spectroscopy, optical microscope, gloss, Vickers hardness, and gonio-spectrophotometer. All results showed that the addition of modified nanoparticles effectively promoted (6 times improvement based on carbonyl index) the weathering resistance of the epoxy silicone coating. It was also concluded that the coatings filled at a low level (0.1 wt%) of GPTMS-modified ZnO provided much more superior weathering performance than those loaded with higher filler content (0.5 and 1 wt%). It was explained by the more crosslinked network formed and the fine distribution of modified filler within the matrix at low filler content.
The purpose of this study is to analyze the relationship between the occurrence of the National Brain Injury Awareness Week and public interest in the concussion topic in Australia through an ...analysis of Internet search activity data from Google Trends.
Online retrospective observational study.
For the keyword “concussion”, the search interest rate over a period of 10 years between August 2012 and August 2022 within Australia has been analyzed using the Google Trends tool. The rising related topics that contributed to the months with the highest search interest were extracted for each year and a trendline analysis was performed to capture temporal patterns.
There was a significant difference in the average search interest between the month of August, when the Brain Injury Awareness Week is annually held, and the rest of the year (d = 0.09, p = 0.017). Also, May and August were the two months with the overall highest search interests (mean ± SD: 73.3 ± 5.16 and mean ± SD: 70.1 ± 5.49, respectively). Trendline analysis showed a positive slope of 0.3081 with R2 = 0.4462 for search interests of concussion over the 10-year period.
The data suggest that there is a growing interest and potential awareness of concussion in Australia that seems highly limited to the context of sports such as football, rugby, and soccer. Major sports events, news coverage, and media exposure appear to be associated with this trend. The study highlights the importance of more investment in producing engaging media content to educate the public on concussion of different causes and improving strategies for National Brain Injury Awareness Week.
•Aluminium nanoparticles were modified by cerium nitrate and silane coupling agent.•Surface modification of the particles significantly enhanced their corrosion resistance.•Silane coupling agent ...enhanced the particle dispersion in the epoxy coating.•Surface modified particles notably improved the corrosion resistance of epoxy.
Aluminium nanoparticles were modified by cerium oxides/hydroxides in order to enhance their corrosion resistance. Then, Ce-Al nanoparticles were functionalized with 3-aminopropyltriethoxy silane (APTES) to enhance their dispersion properties and interfacial interactions. Surface chemistry of the Ce-Al nanoparticles was characterized by energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Field emission scanning electron microscopy (FE-SEM) was utilized to investigate the surface morphology of nanoparticles before and after modification by cerium nitrate. Furthermore, nanoparticles modified with APTES were characterized by Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA). The corrosion resistance of the Ce-Al, Si-Al and Si-Ce-Al samples was studied by measuring the volume of hydrogen gas evolved in an acidic solution. The effect of three types of modified nanoparticles (Ce-Al, Si-Al and Si-Ce-Al) on the corrosion protection properties of the epoxy coatings was studied by an electrochemical impedance spectroscopy (EIS). Results obtained from FE-SEM analysis revealed that the surface modified aluminium particles remained unchanged after modification with cerium nitrate in acidic solution. It was revealed that surface treatment of Ce-Al nanoparticles by APTES changed their surface nature to more hydrophobic and enhanced their dispersion properties in the epoxy coating. Deposition of Ce oxide/hydroxide layer on the nanoparticles surface was realized by XPS and EDS analyses. It was shown that surface modification by Ce film and functionalization of the nanoparticles by APTES significantly enhanced their corrosion resistance. It was shown that addition of Ce- and Si-modified nanoparticles significantly improved the corrosion protection properties of the epoxy coating. Better results were obtained when Si-Ce-Al nanoparticles were incorporated into the coating.
