• Title/Summary/Keyword: demand strength

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Clinical Study on the Alveolar Bone Repair Capacity of Dentin Matrix Block (Dentin Matrix Block의 치조골 복원 능력에 관한 임상적 연구)

  • Kim, Kyung-Wook
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.35 no.1
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    • pp.55-59
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    • 2013
  • In the oral and maxillofacial area, bone defects are created by various reasons and demand for bone grafts, while dental implant implantation has been increased consistently. To solve these problems, there has been development of autogenous tooth-bone graft material (AutoBT$^{(R)}$, Korea Tooth Bank Co., Korea), and we have collected ground reasons to substitute free autobone graft with this material in clinical use. This autogenous tooth-bone graft material is produced in powder type and block type. Block type is useful in esthetic reconstruction of the defect site and vertical and horizontal augmentation of alveolar bone because this type has high strength value, well maintained shape and is less absorbed. Therefore, the author of this study gained favorable result by grafting the block type autogenous tooth-bone graft material after dental implant implantation on the bone defects of the mandibular molar extraction site. Moreover, the author represents this case with literature review after confirming bone remodeling on the computed tomography image and by histological analysis.

A Study on Electrical $MoSi_2$ High Temperature Heating Elements by Additives (첨가제 변화에 따른 $MoSi_2$ 고온발열체의 전기적 특성)

  • Lee, H.I.;Han, S.O.;Koo, K.W.
    • Proceedings of the KIEE Conference
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    • 2001.07c
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    • pp.1405-1407
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    • 2001
  • It was studied to prepare high temperature heating elements using molybdenum disilicide($MoSi_2$). Molybdenum disilicide is widely used as material for manufacturing high temperature heating elements. $MoSi_2$ heating elements could be used at 1700-1900$^{\circ}C$. However, it is relatively expensive, and its demand depends on import. $MoSi_2$ powders was mixed with 4-5wt% of montmorillonites type bentonite as plasticizer and a small amount of $Si_3N_4$, $ThO_2$, and B as additives to prepare specimen of heating elements. Then, it was extruded, dried, sintered and machined followed by heating test. Effects of sintering conditions and amount of additives were investigated, It was sintered effectively at 1,350$^{\circ}C$ for five hours. Electrical resistivity was decreased with increasing of sintering temperature and time, and related with apparent density of the specimens. It was linealy decreased with increasing of sintered density. The heating elements thus prepared was stable at 1700$^{\circ}C$ and the physical properties such as specific electrical resistivity, hardness, apparent density, thermal expansion coefficient, and bending strength were almost identical with those of commercial heating elements.

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Synthesis of Spherical Carbons Containing Titania and Their Physicochemical and Photochemical Properties

  • Oh, Won-Chun;Kim, Jong-Gyu;Kim, Hyuk;Chen, Ming-Liang;Zhang, Feng-Jun;Meng, Ze-Da;Choi, Jong-Geun;Zhang, Kan
    • Journal of the Korean Ceramic Society
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    • v.48 no.1
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    • pp.6-13
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    • 2011
  • In this study, we used activated carbon (AC) and charcoal (CH) as carbon sources with $TiO_2$ powder to prepare spherical carbons containing titania (SCCT) by using phenolic resin (PR) as a bonding agent. The physicochemical characteristics of the SCCT samples were examined by BET, XRD, SEM, EDX, iodine adsorption and compressive strength. The photocatalytic activity was evaluated by measuring the removal efficiency of three kinds of organic dyes: methylene blue (MB), methyl orange (MO) and rhodamine B (Rh.B) under a UV/SCCT system. In addition, evaluation of chemical oxygen demand (COD) of piggery waste was done at regular intervals and gave a good idea about the mineralization of wastewater.

The Study of Kogas Membrane Performance Test for LNG Storage Tank (Kogas 멤브레인 성능평가에 관한 연구)

  • Kim Y.K.;Hong S.H.;Yoon I.S.;Oh B.T.;Seo H.S.
    • Journal of the Korean Institute of Gas
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    • v.6 no.4 s.18
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    • pp.17-22
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    • 2002
  • LNG demand has been rapidly increasing in Korea for a variety of reasons including stable supply, non-polluting, and high combustion efficiency characteristics. One of the most important structural core element of the LNG storage tank is the membrane, consisting of stainless steel. The membrane to be applied inside of LNG storage tank is provided with corrugations to absorb thermal contraction and expansion caused by LNG temperature. Experimental studies are presented to investigate the deformation and strength of the membrane which is designed by Kogas. All experiments are conducted on the basis of RPIS, and we found the results is fully satisfied with the RPIS.

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Properties and Casting Characteristics of Al-Zn-Fe-Si Alloys (Al-Zn-Fe-Si 합금의 물성 및 주조특성)

  • Yun, Ho-Seob;Kim, Jeong-Min;Park, Joon-Sik;Kim, Ki-Tae
    • Journal of Korea Foundry Society
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    • v.33 no.1
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    • pp.8-12
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    • 2013
  • Although aluminum-silicon based commercial casting alloys have been used in applications that demand high electrical or thermal conductivity, new aluminum casting alloys that possess higher conductivities are currently required for advanced applications. Therefore, there is much research into the development of new high conductivity aluminum casting alloys that contain lower amounts of or no silicon. In this research, the properties and casting characteristics of Al-Zn-Fe-Si alloys with various Fe and Si contents were investigated. Two types of AlFeSi phases were formed depending on the Fe and Si contents. As the silicon content increased, the tensile strength of the Al-Zn-Fe-Si alloy increased slightly, while the electrical conductivity decreased slightly. It was also observed that both the fluidity and hot cracking susceptibility of the investigated alloys were closely related to the formation of the AlFeSi phases.

A Study on the Injection Molding Process of Inline Skate Frame Using Moldflow (Moldflow를 이용한 인라인스케이트 프레임의 사출성형공정에 관한 연구)

  • Lee, Hyoung-Woo;Park, Chul-Woo
    • Journal of Advanced Marine Engineering and Technology
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    • v.34 no.2
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    • pp.289-295
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    • 2010
  • Injection molding process is one of the most important methods to produce plastic parts with high efficiency and low cost. Today, injection molded parts have been increased dramatically the demand for high strength and quality applications. In this study, In-line skates are made of Al alloy and plastic materials to replace the frame for the optimization process is all about. I interpreted through mold design, Injection molding process that minimizes the runner and the gate dimension will determine the size and shape. Runner and gate dimensions of change based on availability of the product, I'll discuss the injection molding. This report investigates that the optimum injection molding condition for minimum of shrinkage. The FEM Simulation CAE tool, Moldflow, is used for the analysis of injection molding process.

Development and Durability Evaluation of a Bimaterial Composite Frame by Pultrusion Process (인발성형 공정을 통한 이종재료 복합소재 프레임 개발 및 내구성 평가)

  • Lee, Haksung;Kang, Shinjae
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.23 no.2
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    • pp.145-151
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    • 2014
  • Recently, the growing demand for weight reduction and improved structure durabilityfor commercial vehicles has led to active research into the development and application of suitablecomposite materials. This studysuggests abimaterial composite frame produced by apultrusion process to replace steel frames. We focused on the development of a composite frameconsisting of two types of materialsby mixing anorthotropic material with anisotropic material. The inside layer consisted of an aluminum pipe, and the outside layer was composed of a glass fiber pipe. To determine the strength and failure mechanisms of the composite material, tensile tests, shear tests, and three-point bending tests were conducted, followed by fatigue tests. After static testing, the fatigue tests were conducted at a load frequency of 5 Hz, a stress ratio (R) of 0.1, and an endurance limit of $10^6$ for the S-N curve. The resultsshowed that the failure modes were related to both the core design and the laminating conditions.

Experimental study on simplified steel reinforced concrete beam-column joints in construction technology

  • Teraoka, Masaru;Morita, Koji;Sasaki, Satoshi;Katsura, Daisuke
    • Steel and Composite Structures
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    • v.1 no.3
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    • pp.295-312
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    • 2001
  • The purpose of this paper is to propose a new type of steel reinforced concrete (SRC) beam-column joints and to examine the structural performance of the proposed joints, which simplify the construction procedure of steel fabrication, welding works, concrete casting and joint strengthening. In the proposed beam-column joints, the steel element of columns forms continuously built-in crossing of H-sections (${\Box}$), with adjacent flanges of column being connected by horizontal stiffeners in a joint at the level of the beam flanges. In addition, simplified lateral reinforcement (${\Box}$) is adopted in a joint to confine the longitudinal reinforcing bars in columns. Experimental and analytical studies have been carried out to estimate the structural performance of the proposed joints. Twelve cruciform specimens and seven SRC beam-column subassemblage specimens were prepared and tested. The following can be concluded from this study: (1) SRC subassemblages with the proposed beam-column joints show adequate seismic performances which are superior to the demand of the current code; (2) The yield and ultimate strength capacities of the beam-to-column connections can be estimated by analysis based on the yield line theory; (3) The skeleton curves and the ultimate shear capacities of the beam-column joint panel are predicted with a fair degree of accuracy by considering a simple stress transfer mechanism.

Physical Properties of Hybrid Poplar Flakeboard Bonded with Alkaline Phenolic Soy Adhesives

  • Yang, In;Kuo, Monlin;Myers, Deland J.
    • Journal of the Korean Wood Science and Technology
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    • v.33 no.5 s.133
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    • pp.66-75
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    • 2005
  • Soybean-based adhesives have recently been reconsidered as alternatives to petroleum-based adhesives due to the uncertainty of availability of petrochemical products and the increased demand for wood adhesives. This study was conducted to investigate the adhesive properties of alkaline phenolic soy (APS) resin for hybrid poplar flakeboard. The APS resin was formulated by crosslinking an alkaline soy flour hydrolyzate with lab-prepared PF resin in the soy hydrolyzate to PF resin weight ratios of 70/30, 60/40, and 50/50. The APS resins were used to fabricate homogeneous hybrid poplar flakeboards with different resin solid levels (5%, 7%, and 9%), press temperatures (175 and $200^{\circ}C$), and press times of 8 and 10 minutes. The IB, wet MOR, and dimensional stability properties of board improved with increasing press time, press temperature, and PF level in APS resins. Increasing press time can be used to offset poor IB strength associated with a 9% resin solid level and the excessive moisture content in the mat. The following conditions were concluded to meet the requirements of the CSA standard for exterior-grade flakeboard: a 50% PF level, a 5% resin content, a $200^{\circ}C$ press temperature, and an 8 minute press time.

Seismic performance of RC frames retrofitted with haunch technique

  • Akbar, Junaid;Ahmad, Naveed;Alam, Bashir;Ashraf, Muhammad
    • Structural Engineering and Mechanics
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    • v.67 no.1
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    • pp.1-8
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    • 2018
  • Shake table tests performed on five 1:3 reduced scale two story RC moment resisting frames having construction defects, have shown severe joint damageability in deficient RC frames, resulting in joint panels' cover spalling and core concrete crushing. Haunch retrofitting technique was adopted herein to upgrade the seismic resistance of the deficient RC frames. Additional four deficient RC frames were built and retrofitted with steel haunch; both axially stiffer and deformable with energy dissipation, fixed to the beam-column connections to reduce shear demand on joint panels. The as-built and retrofitted frames' seismic response parameters are calculated and compared to evaluate the viability of haunch retrofitting technique. The haunch retrofitting technique increased the lateral stiffness and strength of the structure, resulting in the increase of structure's overstrength. The retrofitting increased response modification factor R by 60% to 100%. Further, the input excitation PGA was correlated with the lateral roof displacement to derive structure response curve that have shown significant resistance of retrofitted models against input excitations. The technique can significantly enhance the seismic performance of deficient RC frames, particularly against the frequent and rare earthquake events, hence, promising for seismic risk mitigation.