• Elastomers and Composites
• /
• v.56 no.1
• /
• pp.20-31
• /
• 2021

There is an increasing demand for the rolling resistance reduction in truck bus radial (TBR) tires in the tire industry. In TBR tires, natural rubber is used as a base polymer to prevent wear and satisfy required physical properties (cut and chip). A binary filler system (silica and carbon black) is used to balance the durability of the tire and rolling resistance performance. In this study, natural rubber (NR) compounds applied with a binary filler system were manufactured at different cure temperatures for vulcanizate structure analysis. The vulcanizate structures were categorized into carbon black bound rubber, silica silane rubber network, and chemical crosslink density by sulfur. Regardless of the cure temperature, the cross-link density per unit content of carbon black had a greater effect on the properties than silica due to affinity with NR. The relationship analysis between the mechanical, viscoelastic properties with vulcanizate structure could be a guideline for manufacturing practical TBR compounds.

• Advances in nano research
• /
• v.16 no.1
• /
• pp.71-79
• /
• 2024

Nanotechnology is the latest technology developed by humanity, trying to use the molecular properties of materials found in nature to create devices that solve the problems plaguing humanity and their efficiency. Man is also trying to change the meaning of molecules to nano so that a body made up of these particles has all the properties of these particles. Nanotechnology is not a new field but a new approach in all areas. A new perspective in concrete technology has been created by the use of nanoparticles in recent years. Adding silica nanoparticles to concrete mixes improves its properties and increases its strength. However, different results and reported mechanisms explain the behavior of nanoparticles in the mixture; Therefore, it took much work to generalize the results and predict the behavior of nano concretes. This article is about the construction simulation technology of civil engineering based on artificial intelligence, which deals with the effect of nanoparticles on improving concrete properties. This was demonstrated by analyzing laboratory samples in various mixture configurations and observing how silica nanoparticles affected their microstructure with scanning electron microscopy (SEM). Based on SEM measurements, silica nanoparticles have a powerful effect because of their specific surface area. Their increase and decrease must be sought in interacting with the filling and nucleation mechanism and the pozzolanic activity. Each of these mechanisms dominates at different ages of hydration and affects the microstructure and mechanical properties of concrete.

• Journal of Korean Society of Environmental Engineers
• /
• v.30 no.6
• /
• pp.673-679
• /
• 2008

In this study, Mesoporous silica were prepared from hydrothermal synthesis using gel mixture of tetraethylorthosilcate (TEOS) as silica source and cetyltrimethylammonium bromide(CTMABr) as a template. In the optimum synthesis cause, molar ratio of template and silica changed. The surface and structure properties of Mesoporous silica were determined by XRD, SEM, and BET. N$_2$ adsorption isotherm characteristics, including the specific surface area(S$_{BET}$), total pore volume(V$_T$), and average pore diameter(D$_{BJH}$), were determined by BET. Also, the adsorption character of Pb(II) and Cd(II) ion on Mesoporous silica were measured using ICP. As a result, a SBET of 100$\sim$1,500 m$^2$/g was determined from the N$_2$ adsorption isotherm. Also, the average pore diameter of 2$\sim$4 nm. The adsorption of Pb ion and Cd ion on Mesoporous silica become different depending on the pH of solution. The adsorption amount of Mesoporus silica had higher than that of silicagel.

• Journal of the Korean Institute of Gas
• /
• v.13 no.5
• /
• pp.26-32
• /
• 2009

Ni catalysts on mesoporous silica and commercial silica were prepared for the methanation. XRD and TPR analyses indicated that Ni/mesoporous silica had smaller metal particle size and higher metal dispersion than that of Ni/commercial silica. In addition, Ni/mesoporous silica had stronger metal-support interaction. In methanation, Ni/mesoporous silica showed higher CO conversion and methane yield (65%) than Ni/commercial silica (58%). In the characterization results of catalysts after reaction, Ni/commercial silica was deactivated by the collapse of structure and metal sintering, but Ni/mesoporous silica showed stable catalytic performance.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.765-768
• /
• 2008

Silica fume is a very important gradient in UHPC(Ultra High Performance Concrete) and its amount is normally over 25% of cement(wt.%). But we surely need to comprehend the influence of the amount of silica fume on the UHPC. In this paper, it was investigated how the amount of silica fume influence on the properties such as fluidity, compressive strength, elastic modulus, and flexural strength. Furthermore, it was examined the internal micro structure on UHPC through the test of SEM and MIP. In results, If we properly use silica fume in UHPC, fluidity and strength of UHPC was increased. It can be ascertained through the test of MIP that silica fume effectively increased density of UHPC by posolanic reaction and acting as filler. Especially, In case of Cement to silica fume ratio$0.1{\sim}0.25%$, we can be concluded that UHPC has similar to mechanical property.

• Journal of Life Science
• /
• v.13 no.6
• /
• pp.836-842
• /
• 2003

1-(2-Aminophenyl)pyrrole 5 was synthesized by using 1,2-phenylenediamine with 2,5-dimethoxy-tetrahydrofuran in glacial acetic acid. 1-(3-Aminophenyl)pyrrole 7 and 1,3-dipyrrolylbenzene 8 were obtained by using 1,3-phenylene-diamine with 2,5-dimethoxytetrahydrofuran in glacial acetic acid. 1,4-Dipyrrolylbenzene 10 was synthesized by using 1,4-phenylenediamine with 2,5-dimethoxy-tetrahydrofuran in glacial acetic acid. Aminophenylpyrroles 5, 7 and dipyrrolylbenzenes 8, 10 were respectively synthesized by treatment of 1,2-phenylenediamine, 1,3-phenylenediamine, 1,4-phenylene-diamine and 2,5-dimethoxytetrahydrofuran in (1) no solvent or (2) acrylic acid or (3) silica gel or (4) acrylic acid and silica gel or (5) silica gel and glacial acetic acid instead of glacial acetic acid. The best yield for dipyrrolylbenzene 10 was obtained when silica gel and glacial acetic acid was used. 9-Phenyl-carbazole 11 was synthesized by treatment of 1-phenylpyrrole with 2,5-dimethoxy-tetrahydrofuran in glacial acetic acid.

• Journal of the Korea Concrete Institute
• /
• v.27 no.1
• /
• pp.21-28
• /
• 2015

Recent studies on concrete floating structure development focused on connection system of concrete modules. Precast concrete modules are designed to be attached by prestressing in the water, exposing the structure to the loads from water and making the construction difficult. Therefore, a development of bond material became a key issue in successful connection of floating concrete modules. In this study, micro-silica mixed aqua epoxy (MSAE) is developed for the task. Existing primer aqua epoxy, originally used as a bond material for the retrofit of concrete structures using fiber reinforced polymers, is evaluated to find the optimum micro-silica added mix proportion. Micro-silica of 0~4 volume % was mixed in standard mixture of aqua epoxy. Then, the material property tests were performed to study the effect of micro-silica in aqua epoxy by controlling the epoxy silane proportion by 0, ${\pm}5$, ${\pm}10%$. The optimum mix design of MSAE was derived based on the test results. The MSAE was used to connect concrete module specimens with the epoxy thickness variation of 5, 10, and 20mm. Then, 3-point loading test was performed to verify the bond capacity of MSAE. The results show that MSAE improves the bond capacity of concrete module.

• Asian-Australasian Journal of Animal Sciences
• /
• v.6 no.1
• /
• pp.41-44
• /
• 1993

This study was conducted to investigate the chemical components of culm that influencing the resistance to lodging and the in vitro digestibility in indica type rice plants. Indica type rice plants with three levels of lodging resistance were used; resistant type (RT), intermediate type (IT) and susceptible type (ST). For each type there were four varieties. Culm length was shorter in RT and longer in ST (98.1 cm vs. 151.8 cm). Silica content in the culm was highest in RT and lowest in ST (11.0% vs. 7.6%). There was no difference in the level of acid detergent lignin (ADL) between the 3 levels of lodging. For the 12 straw samples, in vitro organic matter digestibility (IVOMD) was negatively correlated with silica content (r = -0.664, p<0.05) but ADL had no significant effect (r = -0.454, p>0.05). Digestibility was more closely correlated with the sum of silica and ADL (r = -0.747, p<0.01) than silica alone. It was concluded that rice plants showed resistance to lodging when the culm was short and its structure was reinforced with larger quantities of silica. However these silicified straws were less digestible.

• Korean Journal of Materials Research
• /
• v.19 no.7
• /
• pp.391-396
• /
• 2009

2-dimensional silica-silica Continuous Fiber-reinforced Ceramic.matrix Composites (CFCCs) were fabricated by a sol-gel infilitration method that has a changing processing condition, such as the repetitions of infilitration. In order to investigate the relationship between the processing condition and the mechanical properties of composites, the mechanical properties of specimens were measured by means of a 4-point flexural strength test while the evidence of strength degradation were microstructurally characterized. There seemed to be a minimum density value that existed at which the delamination between the fabrics would not occur. In the case that the density of silica CFCCs exceeded 1.55 g/$cm^3$, the flexural strength also exceeded approximately 18 MPa at least. By applying the Minimum Solid Area (MSA) analysis of the porous structure, the correlation between the relative density and the mechanical properties of composites will be discussed.

• Clean Technology
• /
• v.16 no.2
• /
• pp.140-144
• /
• 2010

Titania-silica composite materials were obtained by sol-gel method from TiCl4 and TEOS precusors, and they were applied to anode materials of lithium ion battery. Uniformly distributed composite materials can be manufactured by sol-gel method. The composite materials were heat treated by microwave to obtain materials with new properties. The experimental variables were composition of the material, heat treatment temperature, and microwave exposure. The structure and surface properties of the materials were analyzed by XRD, SEM, and the electrochemical capacity was measured with charge/discharge cycler.