• Title/Summary/Keyword: Mesostructure

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Phosphate removal in water by mesostructure based on titanium and silica (티타늄과 실리콘 기반의 메조구조체를 이용한 수중의 인 제거)

  • Lee, Seung-Yeon;Choi, Jae-Woo;Lee, Sang-Hyup;Lee, Ki-Bong;Hong, Seok-Won
    • Journal of Korean Society of Water and Wastewater
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    • v.25 no.5
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    • pp.725-730
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    • 2011
  • In this study, it was investigated that the feasibility of utilizing inorganic mesostructures for removal of phosphate in water. The comparison of the efficiency for phosphate adsorption between inorganic mesostructures was conducted. X-ray diffraction(XRD) and Brunauer-Emmett-Teller(BET) methods were used to characterize these mesostructures. The efficiencies of silica and titanium mesostructures for the removal of phosphate from aqueous solution were investigated. Equilibrium data were analyzed using the Langmuir isotherm. The maximum adsorption capacities of mesostructure adsorbents were found to be 49.3 and 19.5 mg $g^{-1}$ for the titanium and silica mesostructures, respectively. The adsorption kinetics was described by a pseudo third-order kinetic model. The results from this study indicated that the titanium mesostructure has the potential to be utilized for the cost-effective removal of phosphate from wastewater.

A cohesive model for concrete mesostructure considering friction effect between cracks

  • Huang, Yi-qun;Hu, Shao-wei
    • Computers and Concrete
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    • v.24 no.1
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    • pp.51-61
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    • 2019
  • Compressive ability is one of the most important mechanical properties of concrete material. The compressive failure process of concrete is pretty complex with internal tension, shear damage and friction between cracks. To simulate the complex fracture process of concrete at meso level, methodology for meso-structural analysis of concrete specimens is developed; the zero thickness cohesive elements are pre-inserted to simulate the crack initiation and propagation; the constitutive applied in cohesive element is established to describe the mechanism of crack separation, closure and friction behavior between the fracture surfaces. A series of simulations were carried out based on the model proposed in this paper. The results reproduced the main fracture and mechanical feature of concrete under compression condition. The effect of key material parameters, structure size, and aggregate content on the concrete fracture pattern and loading carrying capacities was investigated. It is found that the inner friction coefficient has a significant influence on the compression character of concrete, the compression strength raises linearly with the increase of the inner friction coefficient, and the fracture pattern is sensitive to the mesostructure of concrete.

Characteristics of Phosphorus Adsorption on Titanium Meso-structure Synthesized under Various Conditions of Surfactant (계면활성제의 다양한 조건에서 합성된 티타늄 메조구조체를 이용한 수중의 인 흡착 특성 연구)

  • Choi, Jae-Woo;Choi, Ji-Youn;Lee, Seung-Yeon;Lee, Sang-Hyup
    • Journal of Korean Society of Water and Wastewater
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    • v.24 no.4
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    • pp.413-423
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    • 2010
  • Eutrophication caused by the excessive supply of phosphorus to water has been considered as one of the most important environmental problems. In this study, the titanium mesostrcture, which was prepared with the template of different surfactant, was tested to confirm the applicability as an adsorbent for phosphorus removal and evaluate the phosphorus removal efficiency. X-ray diffraction analysis, phosphorus adsorption istotherm and kinetic test were performed for the titanium mesostructure, synthesized at various base material/surfactant molar ratio and with different surfactant templates. From the results, we found that mesostructure was synthesized at the base material/surfactant molar ratio of 1/0.25 was most uniformly and clearly formed and thus the adsorption capacity was also maximized.

Thermally Induced Mesophase Development in Ethanesilica Films via Macromolecular Templating Approach

  • Cho, Whirang;Char, Kook-Heon;Kwon, Su-Yong
    • Macromolecular Research
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    • v.17 no.9
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    • pp.697-702
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    • 2009
  • Mesoporous ethanesilica thin film was prepared using PEO-PLGA-PEO triblock copolymers as structure-directing agents and (1,2-bis(triethoxysilyl) ethane BTESE; bridged organosilicates) as inorganic precursors via one-step sol-gel condensation of ethanesilica precursors. The mesostructure of ethanesilica films is critically dependent on the processing experimental parameters after the hydrolyzed silica sol mixture was spin-cast. This study examined the effects of the block copolymer template/organosilica precursor ratio in the casting solution and aging period before calcination of the mesostructure. It was further demonstrated that mesoscopic ordering of organosilicate thin films is induced by the rearrangement of block copolymer template/organosilica hybrid during thermal decomposition of the PEO-PLGA-PEO triblock copolymer. The mesoporous structure and morphology were characterized by SAXS, TEM and solid-state NMR measurement.

Modeling mesoscale uncertainty for concrete in tension

  • Tregger, Nathan;Corr, David;Graham-Brady, Lori;Shah, Surendra
    • Computers and Concrete
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    • v.4 no.5
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    • pp.347-362
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    • 2007
  • Due to heterogeneities at all scales, concrete exhibits significant variability in mechanical behavior from sample to sample. An understanding of the fundamental mechanical performance of concrete must therefore be embedded in a stochastic framework. The current work attempts to address the connection between a two-dimensional concrete mesostructure and the random local material properties associated within that mesostructure. This work builds on previous work that has focused on the random configuration of concrete mesostructures. This was accomplished by developing an understanding of the effects of variations in the mortar strength and the mortar-aggregate interfacial strength in given deterministic mesostructural configurations. The results are assessed through direct tension tests that are validated by comparing experimental results of two different, pre-arranged mesostructures, with the intent of isolating the effect of local variations in strength. Agreement is shown both in mechanical property values as well as the qualitative nature of crack initiation and propagation.

Phosphate Adsorption Characteristics of Zirconium Mesostructure Synthesized under Different Conditions (지르코늄 메조구조체의 합성조건 변화에 따른 인 흡착 특성)

  • Lee, Seung-Hak;Lee, Kwan-Yong;Lee, Sang-Hyup;Choi, Yong-Su
    • Journal of Korean Society of Environmental Engineers
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    • v.28 no.6
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    • pp.583-587
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    • 2006
  • In this study, the phosphate adsorption characteristics of zirconium mesostructures synthesized under different conditions were estimated. X-ray diffraction analysis, phosphate adsorption isotherm test and kinetic test was performed for the zirconium mesostructures synthesized at different inorganic/surfactant molar ratio and with different surfactant templates. The test results were analyzed with adsorption models. From this work, it was found that at the inorganic/surfactant molar ratio of 1/0.50($0.013{\cdot}Zr(SO_4){_2}:0.068{\cdot}surfactant:5.55{\cdot}H_2O$), the meso-pores in the material could be most uniformly and clearly formed and thus the adsorption capacity and reaction rate of material could be maximized. And the pore size in the mesostructure increased with the chain length of surfactant template used, and maximum phosphate adsorption amount and reaction rate could be achieved with the zirconium mesostructure synthesized with the surfactant template of dodecyltrimethylammonium bromide.

Analysis of the Type of 3D Printing Development Linked with the Textile Structure Principle (텍스타일 스트럭처 원리와 연계된 3D 프린팅 개발 유형 분석)

  • Kim, Hyojin;Kim, Seongdal
    • Journal of Fashion Business
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    • v.22 no.2
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    • pp.1-13
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    • 2018
  • 3D printing technology, which is expected to play a leading role within the Fourth Industrial Revolution, is becoming distinguished not only in the space, automotive, medical and engineering industries, but also in the area of design. The fashion and textile structures created by 3D printing technology were classified into three types - basic structure, unified structure, and a new physical structure. When traditional weaving, knitting, and stitching was reinterpreted through 3D printing, there were apparent limitations in reproducing the characteristics of fabric structures due to differences in the materials and structures of traditional textiles. New physical structures are being developed to break away from merely reproducing traditional textile structures, and to bring out the characteristics of 3D printing technology. As examples of new physical structures, there are the kinematics structure which utilizes the hinge method, mesostructure cellular material, and the N12 disk structure. Such techniques potentially open a new paradigm of fashion and textile structures. Some innovative aspects of 3D printing technology may result in changes in the methods of collaboration, manufacturing, and distribution. Designers are receiving help from specialists of various backgrounds to merge 3D printing technology to create original works. Also, 3D printing not only makes personalized custom designs available, but shortens the distribution channels, foretelling a change within the fashion and textile industry.

Graphitic Mesostructured Carbon from an Aliphatic Hydrocarbon Precursor

  • Kim, Chy-Hyung;Oh, Teresa
    • Bulletin of the Korean Chemical Society
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    • v.30 no.9
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    • pp.1978-1980
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    • 2009
  • A mesostructured form of carbon was fabricated from a template of mesostructured silica by using pentane, an aliphatic hydrocarbon precursor. To synthesize the mesostructured silica, a buffered (pH of 6.5) mixture of nonionic Pluronic P123 surfactant, sodium silicate, and acetic acid were used. The impregnated silica with Fe$(CO)_5$ (wt 5%) and pentane was placed in a quartz tube, treated with pentane vapor at 800 ${^{\circ}C}$ for two hours to synthesize the mesostructured carbon. The XRD patterns of the carbon replica in the low/wide angle regions, its TEM images, and nitrogen adsorption-desorption isotherm revealed that the long-range framework order of mesostructure with the pore size centered on 2.8 nm was maintained to some extent mainly due to some portions of mesophase carbon that work as a support to fix the hexagonal frameworks by anchoring on the pore surface with an improved graphitic character. The dc conductivity of the mesostructured carbon in pressed powder form at 6.0 MPa was 2.08 S/cm.

Effect of Template Existence on the Textural Properties of Iron-based Catalyst for Fischer Tropsch Reaction

  • Sirikulbodee, Papahtsara;Tungkamani, Sabaithip;Phongksorn, Monrudee;Ratana, Tanakorn;Sornchamni, Thana
    • International Journal of Internet, Broadcasting and Communication
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    • v.7 no.2
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    • pp.96-104
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    • 2015
  • Fischer Tropsch reaction is one of the interesting topic for renewable and clean energy. Polymerization of carbon monoxide or carbon dioxide with hydrogen over metal supported catalyst can produce long chain hydrocarbons. Synthetic liquid hydrocarbons are promising alternative to fossil fuels. This research work has been focused on the synthesis of Fe based catalyst for Fischer Tropsch reaction. Mesoporous silica (MS) support prepared by a precipitation method using two different washing solution, distilled water (DW) and acid in ethanol solution (ET), and different calcination temperature. Then, Fe/MS was prepared by an incipient wetness impregnation method. All of samples were systematically characterized using various physical and chemical techniques. TEM and XRD analysis were used to ensure that the cubic Ia3d mesostructure is stable after calcination. FTIR spectra are useful to ascertain the existence of template in the support. TPR studies were also used to understand the nature of Fe species and their reducibility. The results reveal that washing the support with distilled water and calcination at $550^{\circ}C$ can efficiently remove the triblock copolymer templates. The existence of template in the support affects the textural properties of all catalyst investigated.