• 제목/요약/키워드: Mechanical Stability Evaluation

검색결과 284건 처리시간 0.026초

위생용 부직포의 키토산/은나노 혼합용액 처리에 의한 역학적 특성 변화 (Changes in Mechanical Properties of Sanitary Nonwoven Fabrics by Chitosan/Nanosilver Mixed Solution Treatment)

  • 배현숙
    • 한국염색가공학회지
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    • 제22권2호
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    • pp.163-172
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    • 2010
  • In order to investigate the changes in mechanical properties of sanitary nonwoven fabrics actually used as a top sheet, the fabric was treated with a mixture of chitosan and nanosilver colloidal solution in accordance with the prescribed ratio. The former is a natural polymer with excellent biocompatibility and the latter can give an additional performance while compensating the weaknesses of chitosan of deteriorating adherence efficiency. It was shown that the bending and shearing characteristics of the chitosan/nanosilver treated fabrics decreased, which helped to make it softer, smoother and more flexible. The shape stability and drapability of the treated fabrics improved. As KES-FB system evaluation showed that Koshi was deduced, and both Numeri and Fukurami were increased. Thereby, the chitosan/nanosilver treated fabrics were smoother to provide elasticity. In the change of hand value compared to chitosan only treatment, a better THV was shown in the fabrics treated with chitosan/nanosilver mixed solution than the fabric treated with chitosan alone.

연삭가공조건에 따른 티타늄 합금의 물성치 향상에 관한 연구 (A Study on the Improvement of Physical Properties for Titanium Alloy by the Grinding Conditions)

  • 김원일;이윤경;왕덕현;허순
    • 한국산업융합학회 논문집
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    • 제4권3호
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    • pp.237-242
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    • 2001
  • Ti-6Al-4V alloy can be obtained the stability of organization and product treasure, the evaluation of the cutting ability and the mechanical characteristics after the heat treatment of annealing, solution and aging. The difficulty in machining titanium alloy is how treat the heat generated during the process. Because the heat conductivity of titanium alloy is regardfully low, the heat generated during grinding is accumulated in workpiece. and it causes the increasing of grinding wheel grits' wear and makes the ground surface rough. So, these characteristics in grinding of titanium alloy will change the mechanical properties of the titanium alloy. From this study. the mechanical characteristics of annealed one and solution and aging one treated Ti-6Al-4V alloy after grinding was concerned with checking out the bending strength and hardness. For the result, both of bending strength and hardness were increased at the burned area on the surface. Roughness value was remarkably high at the table speed of 10m/min.

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Establishments of Fabrication and Evaluation Methods for Innovative SiC Fiber Reinforced SiC Matrix Composites

  • Park, Joon-Soo;Kohyama, Akira;Hinoki, Tatsuya
    • 한국해양공학회:학술대회논문집
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    • 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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    • pp.21-24
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    • 2006
  • Based on the improvement in reinforcing SiC fibers and the utilization of very fine nano-SiC powders, the well known liquid phase sintering (LPS) process was drastically improved to become a new process called the Nano Infiltration and Transient Eutectic Phase (NITE) Process. Laboratory scale NITE-SiC/SiC composites demonstrated excellent mechanical properties, thermal conductivity, hermeticity and microstructure stability which made them attractive for not only energy application but many other industrial applications. For the real deployments of these materials, mass production system and evaluation methods, together with the design code and safety assurance systems are essential. The current efforts to establish these bases were introduced.

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이중 암 작업모듈 유압시스템의 안정성 해석 (Stability Analysis of the Hydraulic System for a Dual Arm Work Module)

  • 이재천
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집B
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    • pp.283-288
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    • 2001
  • This study provides analytical evaluation of the Dual-Ann Work Module. The current hydraulic system was modeled using the HyPneu and analyzed to find the cause of the instability. The cause of the instability was determined to be primarily an interacting involving the pilot operated check valves and the counterbalance valves for fail safe mode of operation. A new design concept was developed to eliminate the potential for unstable operation while adequately meeting the need for a fail-safe feature.

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소방 고가사다리차의 설계 변수에 따른 안정성 평가를 위한 구조해석 연구 (A Study on Structural Analysis for Stability Evaluation According to Design Parameters of a Fire Ladder Vehicle)

  • 정훈;김철중;김홍건
    • 한국기계가공학회지
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    • 제19권8호
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    • pp.64-72
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    • 2020
  • In this study, a stability analysis was conducted through finite element analysis (FEA) of a simplified model of a fire ladder truck by changing the ascending angle, turning angle, and boundary conditions between the outrigger and the ground. The results of the analysis showed that decreasing the angle of the ladder car increases the moment due to the ladder weight, decreasing the safety factor despite being under the same load conditions. In the case of a rotating radius, the stability was found to vary depending on the boundary conditions. A comparative analysis in the future with these results and the experimental values from the actual fire ladder truck may determine the most appropriate boundary conditions based on the analysis program. It is expected to predict the risk of damage and rollover by assessing the stability of aerial ladder vehicles under different conditions.

Spatial variability analysis of soil strength to slope stability assessment

  • Lombardi, Mara;Cardarilli, Monica;Raspa, Giuseppe
    • Geomechanics and Engineering
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    • 제12권3호
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    • pp.483-503
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    • 2017
  • Uncertainty is a fact belonging to engineering practice. An important uncertainty that sets geotechnical engineering is the variability associated with the properties of soils or, more precisely, the characterization of soil profiles. The reason is due largely to the complex and varied natural processes associated with the formation of soil. Spatial variability analysis for the study of the stability of natural slopes, complementing conventional analyses, is able to incorporate these uncertainties. In this paper the characterization is performed in back-analysis for a case of landslide occurred to verify afterwards the presence of the conditions of shear strength at failure. This approach may support designers to make more accurate estimates regarding slope failure responding, more consciously, to the legislation dispositions about slope stability evaluation and future design. By applying different kriging techniques used for spatial analysis it has been possible to perform a 3D-slope reconstruction. The predictive analysis and the areal mapping of the soil mechanical characteristics would support the definition of priority interventions in the zones characterized by more critical values as well as slope potential instability. This tool of analysis aims to support decision-making by directing project planning through the efficient allocation of available resources.

각종 편성소재에 따른 스포츠양말의 위생성과 형태안정성에 관한 연구 (A Study of Sports Socks Varying Knitted Fabrics on Hygienic and stability Properties)

  • 이명자;김칠순
    • 복식문화연구
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    • 제7권5호
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    • pp.165-176
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    • 1999
  • The purpose of this study was to evaluate the effect of various knitted fabrics of sports socks on their properties of hygiene and stability. Seventeen men\`s sports socks to represent five groups with different fiber content, knit structure, yarn fineness, and finishing were used. Properties of hygiene and stability of socks were determined. The results were as follows ; 1. Evaluation of Water, vapor and heat transport properties in socks with varing fiber content showed that cotton 100% socks had the highest drop absorbency, wickability, water absorbency and water retention. Polypropylene 100% socks had an excellent wickability and moisture permeability. Acrylic blend socks had the highest thermal resistance. 2. The greatest knit stretch and knit growth of socks having lower power were found to be with cotton 100% socks had the lowest stretch. Acrylic blend socks had a excellent stretch but low fabric growth, which could give a good fir sensation during wear. 3. The commerical antimicrobial finished socks showed excellent durability after repeated cycles of laundering. 4. Length and width shrinkages were found in all laundered samples during initial cycles due to rearrangement by mechanical relaxation. Shrinkages showed no further changes and reached equilibriums after 5 cycles. Cotton 100% or cotton blend socks showed lower dimensional stability than other socks during fabric care.

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350A 벨로우즈형 신축관이음의 내진특성 평가 (Seismic Stability Evaluation of Bellows Type Expansion Joints Piping System(350A))

  • 손인수
    • 한국산업융합학회 논문집
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    • 제23권4_2호
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    • pp.653-659
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    • 2020
  • In this study, seismic verification of the bellows used in the plant field was conducted. The pressure used in the analysis was analyzed by applying the design pressure of 15.7bar. For the seismic analysis, the natural frequency of the bellows system was obtained and the stability of the system was evaluated by static seismic analysis comparing the lowest order natural frequency with the dominant frequency of 33 Hz. The material of the bellows system is STS304, and the safety factor is obtained in comparison with the allowable stress. For the seismic analysis, the design response spectrum was prepared and the maximum acceleration was applied to the static seismic analysis and the stability of the entire system was confirmed. Compared to the structural analysis results, the maximum stress of the bellows system increased by about 16.4% and the maximum strain increased by about 3 times when seismic analysis was performed.

Computer-aided design/computer-aided manufacturing of hydroxyapatite scaffolds for bone reconstruction in jawbone atrophy: a systematic review and case report

  • Garagiola, Umberto;Grigolato, Roberto;Soldo, Rossano;Bacchini, Marco;Bassi, Gianluca;Roncucci, Rachele;De Nardi, Sandro
    • Maxillofacial Plastic and Reconstructive Surgery
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    • 제38권
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    • pp.2.1-2.9
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    • 2016
  • Background: We reviewed the biological and mechanical properties of porous hydroxyapatite (HA) compared to other synthetic materials. Computer-aided design/computer-aided manufacturing (CAD/CAM) was also evaluated to estimate its efficacy with clinical and radiological assessments. Method: A systematic search of the electronic literature database of the National Library of Medicine (PubMed-MEDLINE) was performed for articles published in English between January 1985 and September 2013. The inclusion criteria were (1) histological evaluation of the biocompatibility and osteoconductivity of porous HA in vivo and in vitro, (2) evaluation of the mechanical properties of HA in relation to its porosity, (3) comparison of the biological and mechanical properties between several biomaterials, and (4) clinical and radiological evaluation of the precision of CAD/CAM techniques. Results: HA had excellent osteoconductivity and biocompatibility in vitro and in vivo compared to other biomaterials. HA grafts are suitable for milling and finishing, depending on the design. In computed tomography, porous HA is a more resorbable and more osteoconductive material than dense HA; however, its strength decreases exponentially with an increase in porosity. Conclusions: Mechanical tests showed that HA scaffolds with pore diameters ranging from 400 to $1200{\mu}m$ had compressive moduli and strength within the range of the human craniofacial trabecular bone. In conclusion, using CAD/CAM techniques for preparing HA scaffolds may increase graft stability and reduce surgical operating time.