• Title/Summary/Keyword: Extreme Process

Search Result 445, Processing Time 0.023 seconds

Negative Corona Onset Characteristic of the UHV Conductors Based on the Corona Cage

  • Liu, Yun-Peng;Zhu, Lei;Lv, Fang-Cheng;Xie, Xiongjie
    • Journal of Electrical Engineering and Technology
    • /
    • v.9 no.6
    • /
    • pp.2089-2097
    • /
    • 2014
  • Negative corona onset characteristics of the stranded conductors based on the ultra-high voltage (UHV) corona cage were studied in the paper. Based on the corona self-sustaining criterion in extreme uneven electric fields and the secondary emission process of the photoelectrons, the corona onset calculation model in the UHV corona cage is established and the corona current tests of the single LGJ900-75, 6 bundle LGJ900-75, 8 bundle LGJ400-35 conductors in dry and rain conditions were done in the UHV corona cage, and the rain rates are 2.4 mm/h, 20 mm/h and 30 mm/h. Corona onset electric field strength is gained by E-I tangent method, and the onset electric field strength in dry condition proves that the calculation model can be used to calculate the corona onset characteristics of the bundle conductors in the UHV corona cage. A further analysis proves that: the negative corona onset voltage of the conductor increases with the bundle number and the diameter of the sub conductor, but decreases with the bundle space in the corona cage. The onset electric field strength is influenced little by bundle space and bundle number, but decreases with the increase of the diameter of the sub-conductor. The surface irregularity coefficient decreases with the rain rate.

Significance of Viable but Nonculturable Escherichia coli: Induction, Detection, and Control

  • Ding, Tian;Suo, Yuanjie;Xiang, Qisen;Zhao, Xihong;Chen, Shiguo;Ye, Xingqian;Liu, Donghong
    • Journal of Microbiology and Biotechnology
    • /
    • v.27 no.3
    • /
    • pp.417-428
    • /
    • 2017
  • Diseases caused by foodborne or waterborne pathogens are emerging. Many pathogens can enter into the viable but nonculturable (VBNC) state, which is a survival strategy when exposed to harsh environmental stresses. Pathogens in the VBNC state have the ability to evade conventional microbiological detection methods, posing a significant and potential health risk. Therefore, controlling VBNC bacteria in food processing and the environment is of great importance. As the typical one of the gram-negatives, Escherichia coli (E. coli) is a widespread foodborne and waterborne pathogenic bacterium and is able to enter into a VBNC state in extreme conditions (similar to the other gram-negative bacteria), including inducing factors and resuscitation stimulus. VBNC E. coli has the ability to recover both culturability and pathogenicity, which may bring potential health risk. This review describes the concrete factors (nonthermal treatment, chemical agents, and environmental factors) that induce E. coli into the VBNC state, the condition or stimulus required for resuscitation of VBNC E. coli, and the methods for detecting VBNC E. coli. Furthermore, the mechanism of genes and proteins involved in the VBNC E. coli is also discussed in this review.

Engineering CotA Laccase for Acidic pH Stability Using Bacillus subtilis Spore Display

  • Sheng, Silu;Jia, Han;Topiol, Sidney;Farinas, Edgardo T.
    • Journal of Microbiology and Biotechnology
    • /
    • v.27 no.3
    • /
    • pp.507-513
    • /
    • 2017
  • Bacillus subtilis spores can be used for protein display to engineer protein properties. This method overcomes viability and protein-folding concerns associated with traditional protein display methods. Spores remain viable under extreme conditions and the genotype/phenotype connection remains intact. In addition, the natural sporulation process eliminates protein-folding concerns that are coupled to the target protein traveling through cell membranes. Furthermore, ATP-dependent chaperones are present to assist in protein folding. CotA was optimized as a whole-cell biocatalyst immobilized in an inert matrix of the spore. In general, proteins that are immobilized have advantages in biocatalysis. For example, the protein can be easily removed from the reaction and it is more stable. The aim is to improve the pH stability using spore display. The maximum activity of CotA is between pH 4 and 5 for the substrate ABTS (ABTS = diammonium 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate). However, the activity dramatically decreases at pH 4. The activity is not significantly altered at pH 5. A library of approximately 3,000 clones was screened. A E498G variant was identified to have a half-life of inactivation ($t_{1/2}$) at pH 4 that was 24.8 times greater compared with wt-CotA. In a previous investigation, a CotA library was screened for organic solvent resistance and a T480A mutant was found. Consequently, T480A/E498G-CotA was constructed and the $t_{1/2}$ was 62.1 times greater than wt-CotA. Finally, E498G-CotA and T480A/E498G-CotA yielded 3.7- and 5.3-fold more product than did wt-CotA after recycling the biocatalyst seven times over 42 h.

Experimental and Modeling Studies for the Adsorption of Phenol from Water Using Natural and Modified Algerian Clay

  • Djemai, Ismahane;Messaid, Belkacem
    • Korean Chemical Engineering Research
    • /
    • v.58 no.4
    • /
    • pp.624-634
    • /
    • 2020
  • The ability of natural and modified clay to adsorb phenol was studied. The clay samples were analyzed by different technical instruments, such as X-ray fluorescence (XRF), X-ray diffraction (XRD) and FT-IR spectroscopy. Surface area, pore volume and average pore diameter were also determined using B.E.T method. Up to 73 and 99% of phenol was successfully adsorbed by natural and activated clay, respectively, from the aqueous solution. The experiments carried out show that the time required to reach the equilibrium of phenol adsorption on all the samples is very close to 60 min. The amount of phenol adsorbed shows a declining trend with higher pH as well as with lower pH, with most extreme elimination of phenol at pH 4. The adsorption of phenol increases proportionally with the initial phenol concentration. The maximum adsorption capacity at 25 ℃ and pH 4 was 29.661 mg/g for modified clay (NaMt). However, the effect of temperature on phenol adsorption was not significant. The simple modification causes the formation of smaller pores in the solid particles, resulting in a higher surface area of NaMt. The equilibrium results in aqueous systems were well fitted by the Freundlich isotherm equation (R2 > 0.98). Kinetic studies showed that the adsorption process is best described by the pseudo-second-order kinetics (R2 > 0.99). The adsorption of phenol on natural and modified clay was spontaneous and exothermal.

The use of spectroscopic Ellipsometey for the observation of diamond thin film growth by microwave plasma chemical vapor deposition (마이크로웨이브 플리즈마 화학기상증착에 의한 다이아몬드 박막의 성장 관찰을 위한 분광 Ellipsometry의 이용)

  • 홍병유
    • Journal of the Korean Crystal Growth and Crystal Technology
    • /
    • v.8 no.2
    • /
    • pp.240-248
    • /
    • 1998
  • The plasma chemical vapor deposition is one of the most utilized techniques for the diamond growth. As the applications of diamond thin films prepared by plasma chemical vapor deposition(CVD) techniques become more demanding, improved fine-tuning and control of the process are required. The important parameters in diamond film deposition include the substrate temperature, $CH_4/H_2$ gas flow ratio, total, gas pressure, and gas excitation power. With the spectroscopic ellipsometry, the substrate temperature as well as the various parameters of the film can be determined without the physical contact and the destructiveness under the extreme environment associated with the diamond film deposition. It is introduced how the real-time spectroscopic ellipsometry is used and the data are analyzed with the view of getting the growth condition and the accompanied features for a good quality of diamond films. And it is determined the important parameters during the diamond film growth, which include the final sample will be measured with Raman spectroscopy to confirm the diamond component included in the film.

  • PDF

The Aesthetic Qualities Featured in Vivienne Westwood's Works (비비안 웨스트우드(Vivienne Westwood)의 작품세계와 미적특성)

  • 염혜정
    • Journal of the Korean Society of Costume
    • /
    • v.37
    • /
    • pp.71-88
    • /
    • 1998
  • This study will analyze the aesthetic qual-ities revealed in the work of Vivienne Wes-twood in order to gain an understanding of the development process and uniqueness of modern avant-garde fashion. Westwood gained worldwide recognition in the 1970s as the Punk movement emerged in London. Although her works have often been described as decadent and anti-establishment, her anarchic view of fashion has had a considerable influence on other designers, both in England and around the world. Vivienne Westwood's works can be divided into three periods. In the first period(1971∼78). Westwood design demonstrated elements which were variations of the subcultural Punk style. The noteworthy designs of this period included ripped T-shirts, bondage clothes, and fetishist accoutrements. In the second period(1979∼83), her designs expressed elements from ethnic and primitive tribal societies through the 'Pirate', 'Savages', 'Buffalo Girls', 'Witches' collections, which inspired New Romanticism movement. In the third period (1985∼ ), through works such as 'Mini-Crini'collection, her works identified elements from the old west and used materials such as crinoline and Harris tweed and contemporized them by rearranging the innovative technique. In the end the news synthesis helped formulate new ideas. The aesthetic qualities in Vivienne Wes-twood's works can bed identified with the following themes : Punkature, Erotic Intelligent-sia, Anarchic Collage. First, within Punkature, Westwood's ideas are at the forefront as her impact on the cut of clothes and creative detailing have been considerable. Also, while her ideas can be extreme, her clothes are wear-able, resulting in the synthesis of Punk and couture. Second, as Erotic Intelligentsia, Vivienne Westwood does not present sexuality as a straight forward attribute that fashion so often tends to do, but instead as a matter for inquiry, exploration and debate. She asserts that sexuality is always an interplay between the polarities of masculine and feminine, of dress and undress. Third, as Anarchic Collage, she has taken, juxtaposed, and transformed objects and symbols from dominant culture, like every modern subversive movement from Dada to Punk. She has continued this form of anarchic collage, mixing styles from various times and places, taking them out of their traditional context. From thiss viewpoint, Vivienne Westwood's works can be considered to be made up of past themes merged with is contemporary. The usage of contrasting elements such as Punk and couture to communicate her ideas visually or technically.

  • PDF

Middle School Science Teachers' Philosophical Perspectives of Science (중학교 과학교사들의 과학철학적 관점에 관한 연구)

  • Soh, Won-Ju;Kim, Beom-Ki;Woo, Jong-Ok
    • Journal of The Korean Association For Science Education
    • /
    • v.18 no.2
    • /
    • pp.221-231
    • /
    • 1998
  • Middle school science teachers performed activities to identify their philosophical perspectives of science through a series of "card game" planned for this research. The subjects of the research were 156 middle school science teachers participated in the 1997 in-service science teachers' training course of the Gyeong Sang Nam Do province. The teachers performed the activities for this research for three hours during their workshops. We found that the subjects in the research were turned out predominant in the inductivistic views regardless of their major. gender, and career. In addition, in the process of collective consensus making, views of (a) the criteria of demarcation and (b) the patterns of scientific change were shifted to the extreme inductivism, (c) the epistemological status of scientific knowledge to the relativism, and (d) the scientific methods to the falsificationism, respectively.

  • PDF

A Plastic Analysis of Structures under the Impact Loading (충격하중(衝擊荷重)을 받는 구조물(構造物)의 소성(塑性)모델에 따른 거동분석(擧動分析))

  • Ahn, Byoung Ki;Lee, Sang Ho
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.12 no.2
    • /
    • pp.21-33
    • /
    • 1992
  • Under the intense-impulsive loading, structures are subjected to the wide range of pressures at an instantaneous time. The constitutive laws capable to describe the material behavior under the extreme pressure as well as the low pressure are necessary for the analysis of the structural behavior under the intense -impulsive loadings. In this study, two plastic models, the pressure independent Von-Mises model and the pressure dependent Drucker-Prager model, are employed for the wave propagation analysis. Governing equations of this study are conservation equations of momentum and mass in Lagrangian coordinate system which is fixed to the material. Due to the shock-front which violates the continuity assumptions inherent in the differential equations numerical artificial viscosity is used to spread the shock front over several computational zones. These equations are solved by Finite Difference Method with discretized time and space coordinates. The associate normality flow rule as a plastic theory is implemented to find the plastic strains.

  • PDF

Numerical simulation of VOC decomposition in an arc plasma reactor (수치해석 기법을 이용한 아크 플라즈마 반응기의 VOCs 분해성능 평가연구)

  • Park, Mi-jeong;Jo, Young-min
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.17 no.8
    • /
    • pp.1-7
    • /
    • 2016
  • A range of techniques have been being developed to remove the volatile organic compounds from paining processes. High temperature decomposition of harmful VOCs using arc plasma has recently been proposed, and this work analyzed the extreme hot process by computer-aided fluid dynamics prior to the reactor design. Numerical simulations utilized the conservation equations of mass and momentum. The simulation showed that the fluid flowed down along the inner surface of the centrifugal reactor by forming intensive spiral trajectories. Although the high temperature gas generated by plasma influences the bottom of the reactor, no heat transfer in radial direction appeared. The decomposition efficiency of a typical VOCs, toluene, was found to be a maximum of 67% across the reactor, which was similar to the value (approximately 70%) for the lab-scale test.

A Study of Predicting 3-dimensional Welding Residual Stresses Distribution for T-joint Fillet Specimen (십자형 용접 시편의 3차원 용접 잔류응력 분포 예측에 관한 연구)

  • Yoo, Mi-Ji;Lee, Jang-Hyun;Hwang, Se-Yun;Kim, Kyung-Su;Kim, Sung-Chan
    • Journal of Welding and Joining
    • /
    • v.28 no.2
    • /
    • pp.84-90
    • /
    • 2010
  • Fillet welding accounts for about 80% of all constructing process of ship and ocean structure. T-joint is one of the typical shapes which are frequently reported to experience the fatigue damage when the marine structure meets the storm loads. The fatigue damage is affected by the magnitude of residual stresses on the weld. Recently, many shipping registers and design guidances have required that the fatigue strength assessment method should be compensated by the effect of the residual stress in case that the random loading or storm loading is applied to the marine vessels. This study suggests the computational procedure to analyze the residual stresses of T-joint specimen that is frequently reported to get damaged by the storm loading. Experiment by XRD as well as the 3-D computational welding model is presented in order to get the profile of residual stress. Throughout the comparison of experimental result with the computational result, the computational model was validated. Thereafter, characteristics of he residual stresses in the joint are discussed.