• 제목/요약/키워드: mechanical character

검색결과 160건 처리시간 0.023초

Role of modifiers on the structural, mechanical, optical and radiation protection attributes of Eu3+ incorporated multi constituent glasses

  • Poojha, M.K. Komal;Marimuthu, K.;Teresa, P. Evangelin;Almousa, Nouf;Sayyed, M.I.
    • Nuclear Engineering and Technology
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    • 제54권10호
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    • pp.3841-3848
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    • 2022
  • The effect of modifiers on the optical features and radiation defying ability of the Eu3+ ions doped multi constituent glasses was examined. XRD has established the amorphous nature of the specimen. The presence of various functional/fundamental groups in the present glasses was analyzed through FTIR spectra. The physical, structural and elastic traits of the glasses were explored. The variation in the structural compactness of the glass structure according to the incorporated modifier was enlightened to describe their suitability for a better shielding media. For the examined glasses, the metallization criterion value varied in the range 0.613-0.692, indicating the non-metallic character of the glasses with possible nonlinear optical applications. The computed elastic moduli expose the Li-containing glass (BTLi:Eu) to be tightly packed and rigid, which is a requirement for a better shielding channel. Furthermore, the optical bandgap and the Urbach energy values are calculated based on the optical absorption spectra. The evaluated bonding parameters revealed the nature of the fabricated glasses covalent. In addition, we investigated the radiation attenuation attributes of the prepared Eu3+ ions doped multi constituent glasses using Phy-X software. We determined the linear attenuation coefficient (LAC) and reported the influence of the five oxides Li2O3, CaO, BaO, SrO, and ZnO on the LAC values. The LAC varied between 0.433 and 0.549 cm-1 at 0.284 MeV. The 39B2O3-25TeO2-15Li2O3-10Na2O-10K2O-1Eu2O3 glass has a much smaller LAC than the other glasses.

Parametric study of the wave dispersion in the hydro-elastic system consisting of an inhomogeneously prestressed hollow cylinder containing compressible inviscid fluid

  • Surkay D. Akbarov;Gurbaneli J. Veliyev
    • Coupled systems mechanics
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    • 제12권1호
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    • pp.41-68
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    • 2023
  • The present work is concerned with the study of the influence of inhomogeneous initial stresses in a hollow cylinder containing a compressible inviscid fluid on the propagation of axisymmetric longitudinal waves propagating in this cylinder. The study is carried out using the so-called three-dimensional linearized theory of elastic waves in bodies with initial stresses to describe the motion of the cylinder and using the linearized Euler equations to describe the flow of the compressible inviscid fluid. It is assumed that the inhomogeneous initial stresses in the cylinder are caused by the internal pressure of the fluid. To solve the corresponding eigenvalue problem, the discrete-analytic solution method is applied and the corresponding dispersion equation is obtained, which is solved numerically, after which the corresponding dispersion curves are constructed and analyzed. To obtain these dispersion curves, parameters characterizing the magnitude of the internal pressure, the ratio of the sound velocities in the cylinder material and in the fluid, and the ratio of the material densities of the fluid and the cylinder are introduced. Based on these parameters, the influence of the inhomogeneous initial stresses in the cylinder on the dispersion of the above-mentioned waves in the considered hydro-elastic system is investigated. Moreover, based on these results, appropriate conclusions about this influence are drawn. In particular, it is found that the character of the influence depends on the wavelength. Accordingly, the inhomogeneous initial stresses before (after) a certain value of the wavelength lead to a decrease (increase) of the wave propagation velocity in the zeroth and first modes.

캉길렘의 생명철학에서 개체성과 내재적 규범의 문제 (The Problem of Individuality and Intrinsic Norms in Canguilhem's Philosophy of Life)

  • 황수영
    • 의철학연구
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    • 제15권
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    • pp.3-37
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    • 2013
  • 조르주 캉길렘의 의철학에서 의학은 기술이라고 주장된다. 이는 실용적 의미가 아니라 인간의 전체성을 반영하는 가치론적 지평에서 제시된다. 이러한 의학의 특징이 캉길렘의 철학적 사유의 동기가 된다. 의학적 지식은 생리학의 단순한 응용이 아니라 환자 개인의 체험에 기초한 임상적 관찰에서 비롯한다. 의학이 과학이고 그 실행이 순수 지식의 응용이라면 환자는 수동적 대상에 머물게 된다. 그러나 환자는 질병에 수동적으로 노출되기보다는 자신의 생애를 통해 이미 습득된 능동적 태도에 의해 질병의 위협에 대처한다. 캉길렘은 이 점을 '규범성'이라고 특징짓는다. 규범성은 개인의 삶의 핵심이지만 실증주의 의학은 이를 설명할 수 없다. 여기서 캉길렘의 의학사상의 생기론적 특징이 나타난다. 캉길렘의 규범성 개념은 일인칭 주관과 관련되기 때문에 기계론적 설명방식을 벗어난다. 캉길렘의 독창성은 개체성과 가치 그리고 규범에서 의학의 본질을 도출하는 데 있다.

인종적 타자의 매혹 -로런스의 『께짤코아틀』에 그려진 인종과 성 (The Lure of the Racial Other: Race and Sexuality in D. H. Lawrence's Quetzalcoatl)

  • 김성호
    • 영어영문학
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    • 제55권4호
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    • pp.693-718
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    • 2009
  • Kate Burns, a disillusioned Irish woman in Quetzalcoatl, has alternating feelings of fear, repulsion, oppression, compassion, and fascination vis-à-vis Mexican people. Together, these feelings are constitutive of a psychic process in which an imaginary appropriation of the other takes place. In this process white subjectivity represents or reconstructs the dark race precisely as its other. At the same time, Kate's feelings register her anxious recognition of the resistant, unappropriated being of the dark people: their true 'otherness,' or what Žižek calls "the excess of existence over representation." The otherness, frequently racial and sexual, evokes mixed feelings in the white subject. Kate's at once amorous and aggressive response to Ramón's body provides a case in point. Kate's emotional undulation is considerably mitigated in The Plumed Serpent, the revised version of the novel in which the theme of 'blood-mixing' is pushed to the ultimate point. Yet the interracial marriage resolves neither the racial nor the ontologico-sexual issues raised in the first version. Kate is still attracted to Ramón in his sagacious sensuality but goes on to get married to Cipriano, a pure Indian, only to find his mechanical masculinity ever unpalatable. This shows, not just Lawrence's wilful commitment to the 'blood-mixing' theme, but perhaps his lingering taboo against miscegenation as well. Changes in the plot entail those in the narrative voice. In Quetzalcoatl, Owen, a spectatorial and gossipy character, frequently competes for narration with the fully participant third-person narrator. In The Plumed Serpent, the third-person narrator becomes predominant, now attempting with greater confidence to present the reality of the racial other immediately to European readership. While such immediacy is illusional, narrative insistence on it implies a struggle to displace racial stereotypes and offer an experiential understanding of the other.

Testing and evaluation of the corrosion behavior of Aluminum/Alumina bulk composites fabricated via combined stir casting and APB process

  • Abdalkareem Jasim;Ghassan Fadhil Smaisim;Abduladheem Turki Jalil;Surendar Aravindhan;Abdullah Hasan Jabbar;Shaymaa Abed Hussein;Muneam Hussein Ali;Muataz S. Alhassan;Yasser Fakri Mustafa
    • Advances in materials Research
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    • 제12권4호
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    • pp.263-271
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    • 2023
  • In this study, AA1060/Alumina composites were fabricated by combined stir casting and accumulative press bonding (APB). The APB process was repeated up to six press bonding steps at 300Ċ. As the novelty, potential dynamic polarization in 3.5Wt% NaCl solution was used to study the corrosion properties of these composites. The corrosion behavior of these samples was compared and studied with that of the annealed aluminum alloy 1060 and versus the number of APB steps. So, as a result of enhancing influence on the number of APB process, this experimental investigation showed a significant enhancement in the main electrochemical parameters and the inert character of the Alumina particles. Together with Reducing the active zones of the material surfaces could delay the corrosion process. Also, at higher number of steps, the corrosion resistance of composites improved. The sample produced after six number of steps had a low corrosion density in comparison with high corrosion density of annealed specimens. Also, the scanning electron microscopy (SEM), was used to study the corrosion surface of samples.

알루미늄 허니컴(HC) 구조재 적용 주조형 복합화약 (Structural Support of Aluminum Honeycomb on Cast PBX)

  • 김성한;이근득;박하늘;한민구
    • 한국군사과학기술학회지
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    • 제27권2호
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    • pp.222-229
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    • 2024
  • As the operating condition for the penetrating missile has been more advanced, the survivability of main charge has been strongly required when the warhead impacts the target. Lots of efforts to desensitize explosives such as the development of insensitive molecular explosives or optimizing plastic-bonded explosives(PBX) systems has been made to enhance the survivability of main charge. However, these efforts face their limits as the weapon system require higher performance. Herein, we suggest a new strategy to secure the survivability of main charge. We applied structurally supportable aluminum honeycomb(HC) structure to cast PBX. The aluminum HC structure reinforces the mechanical strength of cast PBX and helps it to withstand external pressure without the reaction like detonation. In this study, impact resistance character, shock sensitivity and internal blast performance of PBXs reinforced with HC structure were investigated according to the application of aluminum HC structure. The newly suggested aluminum HC structure applied to cast PBX was proved to be a promising manufacturing method available for high-tech weapon systems.

치아 및 임플랜트 지지 고정성 국소의치에서 내가동 연결장치의 변형에 관한 유한요소법적 분석 (A FINITE ELEMENT ANALYSIS ON THE DEFLECTION OF IMC IN THE TOOTH AND IMPLANT SUPPORTED FIXED PARTIAL DENTURE)

  • 김창호;최아영;계기성;조규종
    • 대한치과보철학회지
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    • 제35권2호
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    • pp.308-329
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    • 1997
  • A lot of the research paper was reported about the result of influence of IMC (Intra-mobile connector) in the IMZ implant placed solely in the alveolar bone, but reports about the effect of IMC on functional load at state of connecting with natural teeth ere rare. The major propose of this study was find the mechanical character of IMC itself by using the finite element analysis program after simulated variance of condition connected with the natural teeth and implant on funcional load. When first and second premolar was lost, IMZ implant was placed with a diameter of 3.3mm and a length of 13mm with IMC in second premolar area. Rigid connection was done and the non-figid connention was located on the female part of the canine abutment and the implant respectively and then both the infraocclusion of $30{\mu}m$ and the non-infraocclusion under the load of 40kg applied to the portion of the natural teeth, the pontic and the implant. The displacement and the stress of it was estimated and analyzed IMC itself of the rigid connection and the non-rigid connection was grouped. The following result were obtained. 1. In all groups, the displacement of Y-axis was greater than that of X-axis and the aspect of displacement showed that IMC was displaced downward and to the center. 2. There was no differences in the displacement of IMC regardless of the connection type. 3. In the displacement of IMC, I 4 was the least, I 1 and I 3 are similar and I 2 was the greatest. 4. There was no differences in the peak value of maximal stress of IMC regardless of the connection type. 5. In the peak value of maximal stress of IMC, I 4 was the least, I 1 and I 3 were similar, and I 2 was the largest.

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알칼리금속 열전기변환장치의 접합과 출력성능 (Joining and Performance of Alkali Metal Thermal-to-electric Converter (AMTEC))

  • 서민수;이욱현;우상국
    • 대한기계학회논문집A
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    • 제41권7호
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    • pp.665-671
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    • 2017
  • 알칼리금속을 이용한 열전기변환장치(Alkali-Metal Thermal-to-electric Converter)는 열을 전기로 직접 변환하는 기술이다. AMTEC 기술은 기존 에너지기술 대비 고효율성과 고밀도성을 지니는 정적 에너지 변환 장치로서 이론 발전효율이 40%로 높고 단위발전량이 500 W/kg, $2.01W/cm^2$로 우수하다. AMTEC의 작동원리는 작동유체인 소듐이 분압차이에 의해서 고체전해질인 베타알루미나(BASE)의 내부에서 외부로 이온화를 거쳐며 통과하는데, 이때 전자를 주고 받으며 전기를 생성한다. BASE내외부의 분압차 형성을 위해서는 고온내구성과 기밀성이 높은 접합기술이 요구된다. 개발된 접합기술을 이용하여BASE/절연부/금속부 시스템의 안정적인 전기적/구조적 시스템을 구성하고 멀티-셀 모듈들을 제작하여 개방회로 전압과 전류-전압특성을 측정하는 방법으로 AMTEC 모듈전지들의 출력성능과 수명을 평가하였다.

로잉운동의 부하편차 방식 적용에 따른 상하지 생체 역학적 평가 (Evaluation of Bio-Mechanical Character istics According to Loading Deviation Methods dur ing Rowing Exercise)

  • 강승록;정구영;문동안;정장식;김정자;권대규
    • 한국운동역학회지
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    • 제21권3호
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    • pp.369-382
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    • 2011
  • The purpose of this study was to verify the validation of exercise effect with loading deviation during rowing exercise. We performed evaluation of based physical fitness and joint torque before the experiment for finding muscle unbalance. So we recruited twenty four subjects who have bigger muscle strength in more 20% than average one. Subjects divided two groups. One is dominant upper limbs(DU) and the other was dominant lower limbs(DL). Subjects performed rowing exercise using electric equipment (Robo.gym.Humonic.korea). Exercise is performed four sets a day including 25 times a set, and three days a week. Measurement consist of evaluation of based physical fitness and joint torque using biodex(biodex system3.USA). Evaluation of exercise effect performed each week in joint torque of shoulder, lumbar and knee joint and each month in based physical fitness. Also we adapted 30% of 1RM for muscular endurance and 70% of 1RM for muscle strength as exercise load. The results showed that the difference of maximal peak torque were getting increase significantly during exercise. Also difference of various factor in based physical fitness were getting increase significantly except flexibility and agility. This interpreted that rowing exercise with loading deviation types could provide muscle strength and muscular endurance exercise in same time. These results could be interpret to two ways. One is effect of improving physical fitness for rowing exercise and the other meaned validation of loading deviation in rowing exercise. Our study is going to verify the validation of loading deviation during rowing and we found out that loading deviation could provide muscle strength and muscular endurance exercise for improving muscle unbalance. Our study can be used development of exercise equipment and program for normal people with muscle unbalance. Also that provide effect of whole body exercise to anybody.

마산로봇랜드 조경설계 (Landscape Design for Masan Robot Land)

  • 윤성융
    • 한국조경학회지
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    • 제38권3호
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    • pp.115-125
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    • 2010
  • 테마파크는 단순히 여가활동을 위한 오락적 공간이 아닌, 주제라는 관념적 울타리를 가지고 다양한 이야기를 담아내는 곳이다. 그 이야기는 방문자가 얻고, 채우고, 남기고 싶어 하는 '의미를 전하는 공간'으로 로봇랜드는 로봇과 인간 그리고 자연을 담아내고 있다. 본 연구는 민간사업자 선정을 위한 마산로봇랜드 설계공모에서 차순위협상대상자로 당선된 작품의 설계전략과 내용을 서술한 것이다. 계획의 주안점은 첫째, 테마파크의 성공여부인 재방문력을 위한 각 공간들의 구성력과 테마의 전달력에 있으며, 둘째, 기계산업의 핵심적 허브이자 아름다운 해안자원을 지니고 있는 마산의 잠재력을 적극으로 이용함에 있다. 먼저, 로봇, 인간, 자연의 요소별 특성을 융합할 수 있는 신진대사의 선형을 모티브로 이용하여 자연훼손을 최소화하면서 이용자의 욕구와 형태의 변화에 따라 유연하게 반응할 수 있는 공간을 창출하였다. 식재계획은 컬러로 규정된 상징적 의미를 이용하여 진입광장, 기존 산림지, 경사지, 휴양지, 단지 내부, 에코아일랜드 등에 각 공간적 특성에 맞추어 도입하였다. 또한 로봇의 전시 및 교육, 숙박자를 위한 휴양 시설, 다양한 놀이 및 상업시설, 유토피아형 가든의 공간을 테마로 대상지의 용도 및 성격에 맞게 조닝을 설정하여 세부공간을 모색하였으며, 마산로봇랜드가 단순히 경제적 효과뿐 아니라 지역적 정서를 근간으로 정신적 풍요를 만들어내는 참된 문화공간으로 조성될 수 있도록 계획하였다.