• Computers and Concrete
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• v.32 no.4
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• pp.373-381
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• 2023

Fly ash, granulated blast furnace slag, marble waste powder, etc. are just some of the by-products of other sectors that the construction industry is looking to include into the many types of concrete they produce. This research seeks to use surrogate machine learning methods to forecast the compressive strength of self-compacting concrete. The surrogate models were developed using Gradient Boosting Machine (GBM), Support Vector Machine (SVM), Random Forest (RF), and Gaussian Process Regression (GPR) techniques. Compressive strength is used as the output variable, with nano silica content, cement content, coarse aggregate content, fine aggregate content, superplasticizer, curing duration, and water-binder ratio as input variables. Of the four models, GBM had the highest accuracy in determining the compressive strength of SCC. The concrete's compressive strength is worst predicted by GPR. Compressive strength of SCC with nano silica is found to be most affected by curing time and least by fine aggregate.

• Structural Engineering and Mechanics
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• v.76 no.2
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• pp.175-191
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• 2020

In this study, the effect of Nano silica (SiO2) on the buckling strength of the glass fiber reinforced laminates containing the machining process causes holes were investigated. The tests have been applied on two status milled and non-milled. To promote the mechanical behavior of the fiber-reinforced glass epoxy-based composites, Nano sio2 was added to the matrix to improve and gradation. Nano sio2 is chosen because of flexibility and high mechanical features; the effect of Nanoparticles on surface serenity has been studied. Thus the effect of Nanoparticles on crack growth and machining process and delamination caused by machining has been studied. We can also imply that many machining factors are essential: feed rate, thrust force, and spindle speed. Also, feed rate and spindle speed were studied in constant values, that the thrust forces were studied as the main factor caused residual stress. Moreover, entrance forces were measured by local calibrated load cells on machining devices. The results showed that the buckling load of milled laminates had been increased by about 50% with adding 2 wt% of silica in comparison with the neat damaged laminates while adding more contents caused adverse effects. Also, with a comparison of two milling tools, the cylindrical radius-end tool had less destructive effects on specimens.

• Advances in nano research
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• v.16 no.5
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• pp.459-472
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• 2024

Nanotechnology is a popular field in the construction industry due to its multiple functions. It mitigates CO₂ emissions and enhances the desirable properties of concrete by replacing small amounts of cement with supplements. This study assess the sustainability impact of using two different nanoparticles partially replacing the cement with 0.3%, 0.6%, 1.0% of nano silica (NS) and 0.03%, 0.045%, 0.06% of Multi-Walled Carbon Nanotubes (MWCNT) in the green concrete mix developement. Nano-sized fragments at the atomic scale tends to modify the properties of concrete. Concrete may increase its strength, durability by adding nanocomposite materials, which will decrease the amount of nano and micropores in structural parts. The strength of the structural elements can be greatly improved and allowing them to withstand higher loads and resist deformation. It improved durability properties by 64.8% in water absorption, 56.4% in acid attack, 78.1% in sulphate attack, and 53.4% in chloride attack. There was an improvement in compressive strength of 37% and split tensile strength of 90%. SEM, FTIR, and XRD investigations have used to look at the microstructural characteristics of nanoconcrete dictated the microstructure characteristics may be made more consistent and dense by adding nanocomposite materials.

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1664-1668
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• 2012

In this study, we have expanded the applicability of the pre-established generalized preparation protocol to MIPs with a neutral template. The ($4S,5R$hyl-5-phenyl-2-oxazolidinone MIP layer was formed inside a pretreated and silanized fused silica capillary, and its chiral separation performance was examined. Optimization of chiral separation was also carried out. This is the very first report of somewhat successful application of the generalized preparation protocol to a MIP with a genuine neutral template.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.98-98
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• 2010

A epoxy/multilayered silicate nanocomposite was prepared by a new AC electric application method and micro silica particle was poured into the nanocomposite in order to prepare epoxy/micro-and-nano- mixed composites (EMNC). Electric insulation breakdown strength was measured in a sphere-sphere electrode system designed for the prevention of edge breakdown and the data were estimated by Weibull plot. As the exfoliated silicate nano-plates were homogeniously dispersed in the micro silica particles, the insulation property was higher.

• Journal of the Korean Chemical Society
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• v.52 no.4
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• pp.387-393
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• 2008

• Bulletin of the Korean Chemical Society
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• v.27 no.10
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• pp.1562-1566
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• 2006

Mesoporous silica films with three different pore sizes were prepared by using cationic surfactant, non-ionic surfactant, or triblock copolymer as structure directing agents with tetramethylorthosilicate as silica source in order to control the pore size and wall thickness. They were synthesized by an evaporation-induced self-assembly process and spin-coated on Si wafer. Mesoporous silica films with three different pore sizes of 2.9, 4.6, and 6.6 nm and wall thickness ranging from $\sim$1 to $\sim$3 nm were prepared by using three different surfactants. These materials were optically transparent mesoporous silica films and crack free when thickness was less than 1 m m. The photoluminescence spectra found in the visible range were peaked at higher energy for smaller pore and thinner wall sized materials, consistent with the quantum confinement effect within the nano-sized walls of the silica pores.

• Korean Chemical Engineering Research
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• v.47 no.3
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• pp.332-336
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• 2009

When NCAs(non-conductive adhesives) are used for adhesion of micro-electronic devices, they often show problems such as delamination and cracking, due to the differences of CTE(coefficients of thermal expansion) between NCAs and substrates. Additions of inorganic particles or flexibilizers have been performed to solve those problems. The effects of silica addition on thermal/mechanical properties of amino modified siloxane(AMS)/silica/epoxy-nanocomposites were examined. The silica was treated by 3-glycidoxypropyltrimethoxysilane(GPTMS) for better compatibility between silica and epoxy matrix. AMS/silica/epoxy-nanocomposites filled with various amounts of AMS(1 and 3 phr) and various amounts of silica(3, 5 and 7 phr) were prepared. And Tg, moduli and CTE of nanocomposites were analyzed. Tg of AMS/Aerosil(non-modified silica)/epoxy-nanocomposites decreased from 125 to $118^{\circ}C$ with increasing Aerosil contents and moduli increased from 2,225 to 2,523 MPa with increasing Aerosil contents. Tg of AMS/M-silica (modified silica)/epoxy-nanocomposites decreased from 124 to $120^{\circ}C$ with increasing M-silica contents and moduli increased from 1,981 to 2,743 MPa with increasing M-silica contents. CTE of AMS/Aerosil/epoxy-nanocomposites and AMS/M-silica/epoxy-nanocomposites showed decreasing tendency regardless of the surface treatments.

• Bulletin of the Korean Chemical Society
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• v.27 no.7
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• pp.1059-1062
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• 2006

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.3105-3108
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• 2011