• 제목/요약/키워드: strain-rate sensitivity

검색결과 174건 처리시간 0.027초

Rapid Identification of Candida albicans Using Colorimetric Method

  • Kim, Shin Young;Park, Hun-Hee
    • 대한임상검사과학회지
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    • 제45권4호
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    • pp.149-153
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    • 2013
  • Candidiasis is a fungal infection of the most common causes; generally, opportunistic infections occur often in patients with weakened immune systems. Because of high rates in fungal infection patients and increasing frequency of being isolated from clinical materials, quickly identifying of Candida albicans is critical. By identifying 404 yeast cell strains of referred samples via API 20C kits, NGL and PRO tests and Germ tube (GT) test were conducted and compared. In the 3.0 McFarland yeast cells, 0.1% ${\rho}-nitrophenyl-N-acetyl-{\beta}-D-galactosaminide$ (NGL) and 0.04% ${\small{L}}$-proline ${\beta}$-naphtylamide (PRO) were each put in test tubes and incubated at $35^{\circ}C$ for 15, 30, 60 and 90 minutes. Afterwards, 1 drop of 2% NaOH was applied, and if the color turned yellow; it was positive for NGL test. Afterwards, 1% ${\rho}$-dimethylaminocinnamaldehyde was applied, and if the upper layer turned pink or red, it was positive for PRO test. NGL and PRO tests were conducted for all C. albicans and identified accurately within 30 minutes. In NGL, PRO test, false-positive, negative were not seen, whereas, GT test showed false-positive in 1 strain and false-negative in 3 strains. Therefore, sensitivity and specificity of NGL, PRO tests were 100% and 99.5%, respectively, and positive and negative predictive rate were 99.5% and 100%, respectively. However, GT test sensitivity and specificity were 98.5% and 99.5%, respectively, and positive and negative predictive rates were 99.5% and 98.5%, respectively. In conclusion, NGL, PRO tests are better than GT tests for sensitivity and specificity, therefore, these reliable tests will be useful in clinical laboratories.

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Sc과 Misch Metal을 첨가한 Al-Mg 합금의 고온 변형 거동 (High temperature deformation behavior of Sc and Misch metal added Al-Mg alloys)

  • 우기도;유용석;김석원;김동건;양창호
    • 열처리공학회지
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    • 제17권1호
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    • pp.23-28
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    • 2004
  • In this work, the effect of Sc and Mm(misch metal) on the high temperature behavior of Al-Mg alloys was observed. Hardness was increased due to appearance of fine $Al_3Sc$ precipitates. The elongation of Al-Mg-Sc alloy at high temperature was higher than that of Al-Mg-Sc-Mm alloy because Al-Mg-Sc alloy has finer grain sizes than Al-Mg-Sc-Mm alloy. The strain rate sensitivity factor, "m" of Al-Mg-Sc and Al-Mg-Sc-Mm at $475^{\circ}C$ and $1{\times}10^{-2}s^{-1}$ were 0.33 and 0.46, respectively. The activation energy of Al-Mg-Sc and Al-Mg-Sc-Mm alloy for superplastic deformation was 133KJ/mol and 103KJ/mol respectively. The elongation of Al-Mg-Sc alloy at high temperature was decreased by the addition of Mm, but the strength at high temperatures and low strain rate was improved.

Physiological Characteristics and Anti-Diabetic Effect of Pediococcus pentosaceus KI62

  • Kim, Seulki;Hong, Sang-pil;Lim, Sang-Dong
    • 한국축산식품학회지
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    • 제41권2호
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    • pp.274-287
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    • 2021
  • The purpose of this study is to examine the physiological characteristics and anti-diabetic effects of Pediococcus pentosaceus KI62. The α-amylase and α-glucosidase inhibitory activity of P. pentosaceus KI62 was 94.86±3.30% and 98.59±0.52%, respectively. In MRS broth containing 3% maltodextrin inoculated by P. pentosaceus KI62, the amounts of short chain fatty acids (SCFA) were propionic acid 18.05±1.85 mg/kg, acetic acid 1.12±0.07 g/100 mL, and butyric acid 2.19±0.061 g/kg, and those of medium chain fatty acids (MCFA) were C8 0.262±0.031 mg/kg, C10 0.279±0.021 mg/kg, and C12 0.203±0.009 mg/kg. Compared to sixteen antibiotics, P. pentosaceus KI62 had the highest sensitivity to penicillin-G and rifampicin, as well as the highest resistance to vancomycin and ampicillin. The strain also showed higher leucine arylamidase and valine arylamidase activities than other enzyme activities, but it did not produce β-glucuronidase which is carcinogenic enzymes. The survival rate of P. pentosaceus KI62 in 0.3% bile was 91.67%. Moreover, the strain showed a 98.63% survival rate in pH 2.0. P. pentosaceus KI62 exhibits resistance to Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus at rates of 29.41%, 38.10%, 51.72%, and 50.47%, respectively. P. pentosaceus (23.31%) showed a similar adhesion ability to L. rhamnosus GG, the positive control (24.49%). These results show that P. pentosaceus KI62 has possibility as a probiotic with anti-diabetic effects.

Some aspects of load-rate sensitivity in visco-elastic microplane material model

  • Kozar, Ivica;Ozbolt, Josko
    • Computers and Concrete
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    • 제7권4호
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    • pp.317-329
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    • 2010
  • The paper describes localization of deformation in a bar under tensile loading. The material of the bar is considered as non-linear viscous elastic and the bar consists of two symmetric halves. It is assumed that the model represents behavior of the quasi-brittle viscous material under uniaxial tension with different loading rates. Besides that, the bar could represent uniaxial stress-strain law on a single plane of a microplane material model. Non-linear material property is taken from the microplane material model and it is coupled with the viscous damper producing non-linear Maxwell material model. Mathematically, the problem is described with a system of two partial differential equations with a non-linear algebraic constraint. In order to obtain solution, the system of differential algebraic equations is transformed into a system of three partial differential equations. System is subjected to loadings of different rate and it is shown that localization occurs only for high loading rates. Mathematically, in such a case two solutions are possible: one without the localization (unstable) and one with the localization (stable one). Furthermore, mass is added to the bar and in that case the problem is described with a system of four differential equations. It is demonstrated that for high enough loading rates, it is the added mass that dominates the response, in contrast to the viscous and elastic material parameters that dominated in the case without mass. This is demonstrated by several numerical examples.

젤라틴입자응집반응법을 이용한 국내 시판 고추종자의 Tobamovirus 검출 및 오염률 조사 (Detection of Tobamoviruses and Survey on Contamination Rate in Commercial Pepper Seeds Using Gelatin Particle Agglutination Test)

  • 한정헌;장태호;이철호;김영호;나용준
    • 식물병연구
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    • 제7권3호
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    • pp.170-174
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    • 2001
  • 시판고추 종자로부터 Tobamovirus를 검출하고 Tobamovirus 오염률을 조사하고자 gelatin particle agglutination test (GPAT)의 최적조건을 조사하였다. Gelatin 입자에 감작할 담배 모자이크 바이러스 고추 계통에 대한 ${\gamma}$-globulin G 의 최적농도는 100$\mu\textrm{g}$/$m\ell$이었고, GPAT의 바이러스 검출 감도는 효소면역항체법 및 dot immuno-binding assay와 유사하였으며, Tobamovirus 검출을 위한 종자시료의 최적 희석배수는 5배에서 25배였다. 그리고 최적화된 GPAT에 의한 국내시판 고추종자의 Tobamovirus 오염률은 평균 79.1%인 것으로 판명되었다.

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거미의 감각기관을 모사한 초민감 균열기반 진동압력센서 (Ultrasensitive Crack-based Mechanosensor Inspired by Spider's Sensory Organ)

  • 오수연;김태일
    • 마이크로전자및패키징학회지
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    • 제31권1호
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    • pp.1-6
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    • 2024
  • 거미는 진동감각기관을 통하여 미세한 진동까지도 감지해낸다. 뛰어난 진동 감지 능력을 활용해 먹이나 포식자가 발생시키는 진동을 감지하여 공격을 계획하거나 위협을 파악하며 생존에 활용한다. 본 논문은 거미의 진동감각기관을 모사하여 개발된 초민감 진동압력센서에 대해 기술한다. 거미가 진동을 감지하는데 사용하는 감각기관에 위치한 작은 틈에 착안하여 센서에 균열을 생성하였고, 균열의 깊이를 제어하여 외부로부터 오는 압력이나 진동을 매우 민감하게 감지할 수 있는 센서를 개발하였다. 이 센서는 10 N의 인장응력을 적용하여 2%의 변형률에서 게이지 계수가 16000에 도달한다. 이는 높은 신호대잡음비를 가져 정확하게 원하는 진동을 인식할 수 있는 소자로서 외력(압력, 진동)과 생체 신호측정 등 다양한 평가를 통해 센서의 높은 민감도를 증명하였다. 이를 통하여 생체모사 기술을 활용한 새로운 센서의 개발 및 다양한 산업 분야로의 응용 가능성을 제시한다.

경북 동해안 환경에서 분리된 V. parahaemolyticus 및 V. vulnificus의 생태학적 및 항생제 감수성 특성 (Environmental and Antimicrobial Characteristics of Vibrio spp. Isolated from Fish, Shellfish, Seawater and Brackish water samples in Gyeongbuk Eastern Coast)

  • 손진창;박승우;민경진
    • 한국환경보건학회지
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    • 제29권2호
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    • pp.94-102
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    • 2003
  • This study was carried out to investigated the distribution and characteristics of Vibrio spp. isolated from fish and shellfish, seawater and brackish water samples collected from Pohang, Uljin, Yeongduk and Gyeongju in Gyeongbuk Province from April 2000 to October 2000. Total 155 strains of genus Vibrio were isolated from 439 collected samples, and numbers of isolated strains of V. parahaemolyticus and V. vulnificus were 140 and 15, respectively. The isolation rate from the samples collected in Pohang was the highest as 41.5% (76 strains), and wat the highest as 71.4% (30 strains) in brackish water, and was the highest as 55.7% (34 strains) in August. And the optimal pH, temperature, and NaCl concentration for growth of V. parahaemolyticus and V. cholerae were 8.0, 3$0^{\circ}C$ and 2.0%, respectively. In a resistance test for environmental factors, heat and cold resistants of V. parahaemolyticus were higher than those of V. vulnificus, withstanding for 15 minutes at 6$0^{\circ}C$ and 6 days at -18$^{\circ}C$. The pH range for existence of V. parahaemolyticus and V. vulnificus were 4.5~l1.0 and 4.5~10.0, showing the similar resistance to pH. V. parahaemolyticus and V. vulnificus could grow in media containing up to 10.0% and 7.0% NaCl, respectively, Salt-tolerance of V. parahaemolyticus was higher than that of V. vulnificus. In an antibiotics sensitivity test against 16 strains of V. parahaemolyticus, twelve strains were resistant to ampicillin, eight strains were resistant to cephalothin. one strain was resistant to streptomycin, and one strain was resistant to ticarcillin.

A Method to Protect Mine Workers in Hot and Humid Environments

  • Sunkpal, Maurice;Roghanchi, Pedram;Kocsis, Karoly C.
    • Safety and Health at Work
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    • 제9권2호
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    • pp.149-158
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    • 2018
  • Background: Work comfort studies have been extensively conducted, especially in the underground and meteorological fields resulting in an avalanche of recommendations for their evaluation. Nevertheless, no known or universally accepted model for comprehensively assessing the thermal work condition of the underground mine environment is currently available. Current literature presents several methods and techniques, but none of these can expansively assess the underground mine environment since most methods consider only one or a few defined factors and neglect others. Some are specifically formulated for the built and meteorological climates, thus making them unsuitable to accurately assess the climatic conditions in underground development and production workings. Methods: This paper presents a series of sensitivity analyses to assess the impact of environmental parameters and metabolic rate on the thermal comfort for underground mining applications. An approach was developed in the form of a "comfort model" which applied comfort parameters to extensively assess the climatic conditions in the deep, hot, and humid underground mines. Results: Simulation analysis predicted comfort limits in the form of required sweat rate and maximum skin wettedness. Tolerable worker exposure times to minimize thermal strain due to dehydration are predicted. Conclusion: The analysis determined the optimal air velocity for thermal comfort to be 1.5 m/s. The results also identified humidity to contribute more to deviations from thermal comfort than other comfort parameters. It is expected that this new approach will significantly help in managing heat stress issues in underground mines and thus improve productivity, safety, and health.

Microseismic monitoring and its precursory parameter of hard roof collapse in longwall faces: A case study

  • Wang, Jun;Ning, Jianguo;Qiu, Pengqi;Yang, Shang;Shang, Hefu
    • Geomechanics and Engineering
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    • 제17권4호
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    • pp.375-383
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    • 2019
  • In underground retreating longwall coal mining, hard roof collapse is one of the most challenging safety problems for mined-out areas. Identifying precursors for hard roof collapse is of great importance for the development of warning systems related to collapse geohazards and ground control. In this case study, the Xinhe mine was chosen because it is a standard mine and the minable coal seam usually lies beneath hard strata. Real-time monitoring of hard roof collapse was performed in longwall face 5301 of the Xinhe mine using support resistance and microseismic (MS) monitoring; five hard roof collapse cases were identified. To reveal the characteristics of MS activity during hard roof collapse development and to identify its precursors, the change in MS parameters, such as MS event rate, energy release, bursting strain energy, b value and the relationships with hard roof collapse, were studied. This research indicates that some MS parameters showed irregularity before hard roof collapse. For the Xinhe coalmine, a substantial decrease in b value and a rapid increase in MS event rate were reliable hard roof collapse precursors. It is suggested that the b value has the highest predictive sensitivity, and the MS event rate has the second highest.

마찰교반용접(FSW) 된 알루미늄 합금(AA6111-T4, AA5083-H18) 및 DP강 판재의 인장 실험시 파단 현상 해석 (Analysis of Failure Phenomena in Uni-axial Tension Tests of Friction Stir Welded AA6111-T4, AA5083-H18 and DP-Steel)

  • 박상준;엄기문;마닝;안강환;정경환;;;;정관수
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2007년도 춘계학술대회 논문집
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    • pp.258-261
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    • 2007
  • Failure phenomena in uni-axial tension test were experimentally and numerically investigated for AA6111-T4, AA5083-H18 and DP-Steel, which were friction-stir welded with the same and different thicknesses. Forming limit diagram(FLD) was measured using hemispherical dome stretching tests for base materials and also predicted by Hill's bifurcation and M-K theories for welded areas. Finite element simulations well predicted hardening behaviors, failure locations as well as failure patterns for the uni-axial tension tests especially utilizing very fine meshes and FLD along with stress softening.

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