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Development of System Model for Integrated Information Management of Construction Material (건설자재 통합정보 관리를 위한 시스템 모델 구현)

  • Han, Choong-Han;Ju, Ki-Bum
    • The KIPS Transactions:PartD
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    • v.16D no.3
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    • pp.433-440
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    • 2009
  • As information technology of constructional area develops recently, web-based on-line system is rapidly increasing to provide information on diverse constructional materials so as to enhance productivity of constructional business and to reduce cost. Since the constructional materials information provided by these systems, i.e., quality, specification, etc are not standardized, however, the staffs on the constructional site suffer considerable difficulties in using materials information when acquiring information on specific materials, e.g., using diverse information systems or repeating similar jobs. Thus, this research typified information items of constructional materials on the basis of GDAS and designed multi system model to control integrated information on constructional materials. This system can efficiently control and utilize materials information by supporting automatic classification of constructional materials to which OmniClass Part-22 and UNSPSC are applied, conditional complex retrieval of materials information, real-time automatic embodiment of electronic catalog and retrieving/controlling RFID.

Two-body wear behavior of human enamel versus monolithic zirconia, lithium disilicate, ceramometal and composite resin

  • Habib, Syed Rashid;Alotaibi, Abdulaziz;Al Hazza, Nawaf;Allam, Yasser;AlGhazi, Mohammad
    • The Journal of Advanced Prosthodontics
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    • v.11 no.1
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    • pp.23-31
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    • 2019
  • PURPOSE. To investigate and compare the surface roughness (SR), weight and height of monolithic zirconia (MZ), ceramometal (CM), lithium disilicate glass ceramic (LD), composite resin (CR), and their antagonistic human teeth enamel. MATERIALS AND METHODS. 32 disc shaped specimens for the four test materials (n=8) and 32 premolars were prepared and randomly divided. SR, weight and height of the materials and the antagonist enamel were recorded before and after subjecting the specimens to 240,000 wear-cycles ($49N/0.8Hz/5^{\circ}C/50^{\circ}C$). SR, height, weight, and digital microscopic qualitative evaluation were measured. RESULTS. CM ($0.23+0.08{\mu}m$) and LD ($0.68+0.16{\mu}m$) exhibited the least and highest mean difference in the SR, respectively. ANOVA revealed significance (P=.001) between the materials for the SR. Paired T-Test showed significance (P<.05) for the pre- and post- SR for all the materials. For the antagonistic enamel, no significance (P=.987) was found between the groups. However, the pre- and post- SR values of all the enamel groups were significant (P<.05). Wear cycles had significant effect on enamel weight loss against all the materials (P<.05). CR and MZ showed the lowest and highest height loss of 0.14 mm and 0.46 mm, respectively. CONCLUSION. MZ and CM are more resistant to SR against the enamel than LD and CR. Enamel worn against test materials showed similar SR. Significant variations in SR values for the tested materials (MZ, LD, CM, and CR) against the enamel were found. Wear simulation significantly affected the enamel weight loss against all the materials, and enamel antagonist against MZ and CM showed more height loss.

Evaluation of Surface Macrostructure and Mechanical Properties of Porous Surface Ti-HA Biomaterial Fabricated by a Leaching Process (Leaching 공정으로 제조한 표면 다 기공 Ti-HA 생체재료의 표면 조직 및 기계적 성질의 평가)

  • Woo, Kee Do;Kang, Duck Soo;Moon, Min Seok;Kim, Sang Hyuk;Liu, Zhiguang;Omran, Abdel-Nasser
    • Korean Journal of Metals and Materials
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    • v.48 no.4
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    • pp.369-375
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    • 2010
  • Ti-6Al-4V ELI alloy, which is commonly used as a biomaterial, is associated with a high elastic modulus and poor biocompatibility. This alloy presents a variety of problems on several areas. Therefore, the development of good non-toxic biocompatible biomaterials with a low elastic modulus is necessary. Particularly, hydroxyapatite (HA) is an attractive material for human tissue implantation. This material is widely used as artificial bone due to its good biocompatibility and similar composition to human bone. Many scientists have studied the fabrication of HA as a biomaterial. However, applications of bulk HA compact are hindered by the low strength of HA when it is sintered. Therefore, HA has been coated on Ti or Ti alloy to facilitate good bonding between tissue and the HA surface. However, there are many problems when doing this, such as the low bonding strength between HA and Ti due to the different thermal expansion coefficients and mechanical properties. In this study, a Ti-HA composite with a porous surface was successfully fabricated by pulse current activated sintering (PCAS) and a subsequent leaching process.

Incorporation of amoxicillin-loaded microspheres in mineral trioxide aggregate cement: an in vitro study

  • Fabio Rocha Bohns;Vicente Castelo Branco Leitune;Isadora Martini Garcia;Bruna Genari;Nelio Bairros Dornelles Junior;Silvia Staniscuaski Guterres;Fabricio Aulo Ogliari;Mary Anne Sampaio de Melo;Fabricio Mezzomo Collares
    • Restorative Dentistry and Endodontics
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    • v.45 no.4
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    • pp.50.1-50.11
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    • 2020
  • Objectives: In this study, we investigated the potential of amoxicillin-loaded polymeric microspheres to be delivered to tooth root infection sites via a bioactive reparative cement. Materials and Methods: Amoxicillin-loaded microspheres were synthesized by a spray-dray method and incorporated at 2.5% and 5% into a mineral trioxide aggregate cement clinically used to induce a mineralized barrier at the root tip of young permanent teeth with incomplete root development and necrotic pulp. The formulations were modified in liquid:powder ratios and in composition by the microspheres. The optimized formulations were evaluated in vitro for physical and mechanical eligibility. The morphology of microspheres was observed under scanning electron microscopy. Results: The optimized cement formulation containing microspheres at 5% exhibited a delayed-release response and maintained its fundamental functional properties. When mixed with amoxicillin-loaded microspheres, the setting times of both test materials significantly increased. The diametral tensile strength of cement containing microspheres at 5% was similar to control. However, phytic acid had no effect on this outcome (p > 0.05). When mixed with modified liquid:powder ratio, the setting time was significantly longer than that original liquid:powder ratio (p < 0.05). Conclusions: Lack of optimal concentrations of antibiotics at anatomical sites of the dental tissues is a hallmark of recurrent endodontic infections. Therefore, targeting the controlled release of broad-spectrum antibiotics may improve the therapeutic outcomes of current treatments. Overall, these results indicate that the carry of amoxicillin by microspheres could provide an alternative strategy for the local delivery of antibiotics for the management of tooth infections.

Development of Discharge Electrode for Machining Connector Mold applying MIM Process (MIM 공법 적용 커넥터 금형 가공용 방전 전극 개발)

  • Shin, Kwang-Ho;Jeon, Yong-Jun;Heo, Young-Moo
    • Design & Manufacturing
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    • v.8 no.2
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    • pp.37-40
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    • 2014
  • A discharge electrode plays a role of shaving off workpiece with spark generated by current in discharge machining. Accordingly, for the discharge electrode, an electrode with excellent wear resistance is necessary. Generally, Graphite and Cu are used as the materials of the electrode, and recently Cu-W is mainly used as an electrode with excellent wear resistance. However, the form of the electrode generally used is produced mostly using cutting work, so a lot of costs incur if several similar forms are needed. Thus, this study developed a Cu-W electrode using Metal Injection Molding (MIM) process to produce similar forms with excellent productivity and a great quantity of electrodes in a similar form in discharge machining and carried out a discharge machining test. In developing an electrode applying MIM, predicting contraction of a product in a sintering process, a mold expansion ratio of 1.29486 was given, but the actual product showed a percentage of contraction 24% to 32%, which showed a difference of 3% to 5%. In addition, to verify wear resistance of the discharge electrode, abrasion loss was measured after the discharge.

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Object Material Confirmation for Source Code Comparison on Embedded System (임베디드 시스템의 동일기능 소스코드 유사도 분석 요구사항)

  • Kim, Do-Hyeun;Lee, Kyu-Tae
    • Journal of Software Assessment and Valuation
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    • v.17 no.1
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    • pp.25-30
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    • 2021
  • In case of evaluating the similarity of the source code analysis material in the embedded system, the provided source code must be confirmed to be executable. However, it is currently being in which compilation and interface matching with hardware are provided in an unconfirmed materials. The complainant assumes that many parts of the source code are similar because the characteristics of the operation are similar and the expression of the function is similar. As for the analysis result, the analysis result may appear different than expected due to these unidentified objects. In this study, the improvement direction is sugested through the case study by the analysis process of the source code and the similarity of the unverified source code.

Comparison of Damping Capacities in Mg-Al and Mg-Zn Solid Solutions (Mg-Al 및 Mg-Zn 고용체의 진동감쇠능 비교)

  • Joong-Hwan Jun
    • Journal of the Korean Society for Heat Treatment
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    • v.36 no.6
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    • pp.389-395
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    • 2023
  • Damping capacities of Mg-2.5%Al and Mg-2.5%Zn (in atomic) solid solutions were comparatively investigated in order to clarify the influence of solutionized Al and Zn elements on the damping characteristics of Mg. In this study, solid solutions with similar grain size were obtained by solution treatment at 678 K for different times (24 h for Mg-2.5%Al and 36 h for Mg-2.5%Zn), followed by water quenching at RT. The Mg-2.5%Al and Mg-2.5%Zn solid solutions showed similar damping capacities in the strain-amplitude independent region of 1 × 10-6 ~ 1 × 10-5 and in the strain-amplitude dependent region below 6 × 10-4, over which the Mg-2.5%Zn solid solution possessed better damping capacity than the Mg-2.5%Al solid solution. The damping tendencies depending on strain-amplitude for the two solid solutions were analyzed and discussed in terms of similar length between weak pinning points (solutes) and different solute/dislocation interaction forces in Granato-Lücke model.

Basic Experimental Study on Drying Characteristics of Household Textiles (가정용 직물들의 건조 특성에 대한 기초 실험 연구)

  • Soo-Jin Park;Jeong-Su Kim;Hyo-Young Cha;Kyoung-Min Noh;Jeongbae Kim
    • Journal of Institute of Convergence Technology
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    • v.13 no.1
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    • pp.1-6
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    • 2023
  • Fast drying after squeezing has known as important for fabrics such as household towels and dishcloths due to the nature of their use. In this study, drying experiments with time were conducted on various fabrics made of materials widely used in homes using a simple experimental device. Similar to the results of previous experimental studies, it was found that in the case of fabrics of the same material with different weight (or thickness), the drying rate over time was similar. In the case of dimensionless weight and time, which are non-dimensionalized by initial weight and complete drying time, the drying characteristics of the fabrics tested in this study were found to have similar drying rates for each mode at both high and low speeds.

A study on the black core formation of artificial lightweight aggregates at various sintering atmospheres (인공경량골재의 소성조건이 블랙코어에 미치는 영향)

  • Kim, Yoo-Taek;Ryu, Yu-Gwang;Jang, Chang-Sub;Lee, Ki-Gang;Kang, Seung-Gu;Kim, Jung-Hwan
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.19 no.6
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    • pp.318-323
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    • 2009
  • The lightweight aggregates made of bottom ash (70 wt%) and dredged soil (30 wt%) were prepared to investigate the property differences at various sintering atmospheres. The green aggregates were sintered at $1150^{\circ}C$ and $1200^{\circ}C$ with oxidized, neutralized and reduced atmospheres. The aggregates sintered with oxidized atmosphere showed a clear border between shell and black core area. However, the aggregates sintered with a reduced atmosphere showed only black core area in the entire cross-section of the aggregates. The black core area of the aggregates sintered with a neutralized atmosphere increased with increasing $N_2$ gas flow rates. It was determined that the sintering atmosphere was similar to that of rotary kiln when the CO gas flow was 100 cc/min to make a reduced atmosphere in tube furnace. The water absorption rates of both aggregates from tube furnace with reduced atmosphere and rotary kiln were very similar to each other.

Observations on the Modulated Structure in Pyrochlore-type Compounds, $In_2(Ti_{1.7}Zn_{0.3})O_{0.67}$ and $In_2(Ti_{1.7}Mg_{0.3})O_{6.7}$ (Pyrochlore형 화합물 $In_2(Ti_{1.7}Zn_{0.3})O_{0.67}$$In_2(Ti_{1.7}Mg_{0.3})O_{6.7}$에서의 변조구조 관찰)

  • Lee, Hwack-Joo;Park, Hyun-Min;Cho, Yang-Koo;Ryu, Hyun;Nahm, Sahn;Bando, Y.
    • Applied Microscopy
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    • v.29 no.4
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    • pp.471-477
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    • 1999
  • Microstructural observations on the pyrochlore-type $Lu_2Ti_2O_7$ and the similar type of compounds, $In_2(Ti_{1.7}Zn_{0.3})O_{6.7}$ and $In_2(Ti_{1.7}Mg_{0.3})O_{6.7}$ which were made by the isothermal heat-treatment at 1623K for 18 days in Pt tube, were carried out using a top-entry HRTEM working at 200 kV. The modulated structures were found in both compounds, however, not in $Lu_2Ti_2O_7$. From the electron diffraction pattern analysis, the modulated superlattices are incommensurate and are 2.69 times of sublattices along (220) direction. The high resolution TEM images have shown that the superlattices consist of alternate superlattices which are composed of two or three sublattices, resulting in the average of 2.7 times of sublattices in accordance with the analysis of electron diffraction patterns. The crystal structures of both compounds are found to quite similar to those of pyrochlore, however the evidence that the cubic axes are slightly deviated from right angle. The modulated structure has gradually changed to the unmodulated structure induced by electron irradiation.

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