• Title/Summary/Keyword: Cyclic Change

Search Result 404, Processing Time 0.028 seconds

A Study on the Cycle of Western Hair Style′s Change in 20th Century (20세기 서구 여성 헤어스타일 변화의 주기성 연구)

  • 박길순;이주연
    • The Research Journal of the Costume Culture
    • /
    • v.4 no.3
    • /
    • pp.383-394
    • /
    • 1996
  • Even it's not easy to in the cycle of the change without the qualification of the data, but we can try to figure out a cycle of change in fashion as Kroeber used content analysis. As content analysis with quantitative data increases the objectivity, especially in the case of highly complex materials like s appearance, multi-directional research method; quantitative and qualitative methods are combined in this study. In this research, first the change in hair length(HL), hair width(HW), hair height(HH) was examined to find out possible cyclic aspects of change in each elements and the significant relationships among the hair style was probed and the cyclic aspects between hair style elements and skirt style elements were compared. The data was analyzed by using Time series analysis and Pearson correlation coefficients. The statistical analysis of the hair style of 20th century showed that the hair style's elements changed independently and indicated the cyclic aspects in hair style as Kroeber's fashion cycle. To consider of this result, the hair style changed in a cyclic pattern, its pattern were different from skirt style's. And as hair style's change was affected by change, the hair styles change appeared during wars and disappeared during a social stabilization; this result supports social change theory.

  • PDF

The Effect of Cyclic Loading History on the Creep of $SiC_f/Si_3N_4$ Fiber-reinforced Composite (사이클 하중이력이 $SiC_f/Si_3N_4섬유강화 복합재료의 크리프에 미치는 영향)

  • 박용환
    • Journal of the Korean Society of Safety
    • /
    • v.15 no.4
    • /
    • pp.35-40
    • /
    • 2000
  • The influence of cyclic loading history on the creep behavior of the 30 vol% hot-pressed $SiC_f/Si_3N_4copmposite was experimentally investigated at $1200^{\circ}C$. The duration of loading/unloading had great effects on the creep behaviors. The short term duration cyclic loading history test results showed significant reduction in the primary and steady-state creep rates. For example, 300sec loading/300sec unloading history resulted in 70% lower steady-state creep rate than that of the continuous loading. However the long term duration cyclic loading history test results showed little change in creep rates compared to those of the continuous one. The reason for the significant change in the short term duration cycles was estimated due to the change in the stress redistribution between the fiber and matrix during the creep recovery in the primary stage.

  • PDF

Behaviour of Nak-dong River Sand on Cyclic Stress History (낙동강 모래의 반복응력이력에 의한 거동)

  • 김영수;박명렬;김병탁;이상복
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2000.11a
    • /
    • pp.295-302
    • /
    • 2000
  • Earthquakes not only produce additional load on the structures and underlying soil, but also change the strength characteristics of the soil. Therefore, in order to analyze soil structures for stability, the behaviour after earthquake must be considered. In this paper, a series of cyclic triaxial tests and monotonic triaxial tests were carried out to investigate the undrained shear strength and liquefaction strength characteristics of Nak-Dong River sand soils which were subjected to cyclic loading. The sample was consolidated in the first stage and then subjected to stress controlled cyclic loading with 0.1Hz. After the cyclic loading, the cyclic-induced excess pore water pressure was dissipated by opening the drainage valve and the sample was reconsolidated to the initial effective mean principal stress(p/sub c/'). After reconsolidation, the monotonic loading or cyclic loading were applied to the specimen. In the results, the undrained shear strength and liquefaction strength characteristics depended on the pore pressure ratio(Ur=U/p/sub c/'). The volume change following reconsolidation can be a function of cyclic-induced excess pore water pressure and the maximum double amplitude of axial strain.

  • PDF

Dielectric and Remnant Mechanical Properties Due to Cyclic Stress in PZT Ceramics (반복응력에 따른 PZT 세라믹스의 유전 및 잔류 기계적 특성)

  • 태원필;김송희
    • Journal of the Korean Ceramic Society
    • /
    • v.31 no.8
    • /
    • pp.829-834
    • /
    • 1994
  • The aim of this study is to investigate the changes in dielectric properties, Young's modulus and remnant compressive strength with compressive cyclic loading in PZT of tetragonal, MPB and rhombohedral composition. Higher relative dielectric constants appeared in the poled condition than the unpoled condition for all the compositions. After poling treatment remarkably higher relative dielectric constants were observed particularly in MPB, tetragonal compositions. Until five percent of the expected fatigue life was exhausted, the dielectric constant increased with compressive cyclic stress in MPB and rhombohedral while it remained nearly constant in tetragonal. During the subsequent compressive cyclic stress, dielectric constant decreased in all the three compositions. As the compressive cyclic stress is applied the change of Young's modulus was coincided with the change of remnant compressive strength.

  • PDF

Determination of Chaboche Cyclic Combined Hardening Model for Cracked Component Analysis Using Tensile and Cyclic C(T) Test Data (표준 인장시험과 반복하중 C(T) 시험을 이용한 균열해석에서의 Chaboche 복합경화 모델 결정법)

  • Hwang, Jin Ha;Kim, Hune Tae;Ryu, Ho Wan;Kim, Yun Jae;Kim, Jin Weon;Kweon, Hyeong Do
    • Transactions of the Korean Society of Pressure Vessels and Piping
    • /
    • v.15 no.2
    • /
    • pp.31-39
    • /
    • 2019
  • Cracked component analysis is needed for structural integrity analysis under seismic loading. Under large amplitude cyclic loading conditions, the change in material properties can be complex, depending on the magnitude of plastic strain. Therefore the cracked component analysis under cyclic loading should consider appropriate cyclic hardening model. This study introduces a procedure for determining an appropriate cyclic hardening model for cracked component analysis. The test material was nuclear-grade TP316 stainless steel. The material cyclic hardening was simulated using the Chaboche combined hardening model. The kinematic hardening model was determined from standard tensile test to cover the high and wide strain range. The isotropic hardening model was determined by simulating C(T) test under cyclic loading using ABAQUS debonding analysis. The suitability of the material hardening model was verified by comparing load-displacement curves of cyclic C(T) tests under different load ratios.

Mutant cAMP Receptor Protein Binds to DNA without DNA Bending (DNA 벤딩(휨) 없이 돌연변이 cAMP 수용체 단백질의 결합)

  • Gang, Jong-Back
    • Journal of Life Science
    • /
    • v.16 no.7 s.80
    • /
    • pp.1225-1228
    • /
    • 2006
  • Cyclic AMP receptor protein (CRP) complexed with cAMP binds to DNA and induces sharp DNA bending around ${\sim}90$ degree. Previous publication (5), however, reported that mutant CRP:cGMP complex showed high migration rate relative to mutant CRP:cAMP complex on native polyacrylamide gel. To confirm DNA structural change in the presence of CRP and cyclic nucleotide, molar cyclization factor $(j_M)$ [13] was measured with 6 constructed DNA fragments. Nonlinear regression analysis of $j_M$ data indicated that mutant CRP did not induce DNA bending in the presence of cGMP but bent DNA in the presence of cAMP without any helical twist change in DNA.

The Change of the Cyclic Aging Characteristics under Salt-fog/Heating on Silicone Rubber by ATH Additions (ATH 첨가에 의한 실리콘 고무의 염무/열 반복열화 특성 변화)

  • Lee, Chung;Kim, Ki-Yup;Kim, Gyu-Baek;Ryu, Boo-Hyung
    • Journal of the Korean Society of Safety
    • /
    • v.20 no.3 s.71
    • /
    • pp.58-63
    • /
    • 2005
  • In this research, silicone rubber with additions of inorganic filler, alumina trihydrate$(Al(OH)_3\;:\;ATH)$, was aged acceleratedly and cyclically by the salt-fog and heating. The optimum amount of ATH addition to silicone rubber have been investigated by measurements of leakage current in the change of electrical properties and tensile strength, %elongation in mechanical properties and FT-IR, TG, SEM in the change of the chemical properties. With regard to un-aged silicone rubber, as the ATH addition amount increases, conductive path formation time was shortened in the electrical properties and tensile strength was increased, %elongation was decreased. In case of identical ATH addition amount, as cyclic aging increases, surface resistivity, tensile strength and %elongation were decreased. Considering the cyclic aging, the most effective amount of ATH addition was about 90phr.

Effect of cyclic Change of Wet Bulb Temperature During Yellowing Stage on Chemical Properties of Flue-Cured Tobacco (황색종 cyclic 건조엽의 화학성분 특성)

  • Lee, Chul-Hwan;Jin, Jeong-Eui;Han, Chul-Soo
    • Journal of the Korean Society of Tobacco Science
    • /
    • v.20 no.1
    • /
    • pp.19-25
    • /
    • 1998
  • The bulk curing experiment to the improve the quality of flue-cured leaves were carried out to evaluate relationship between cyclic curing and conventional curing method. We studied the effect of the cyclic change of wet bulb temperature at the yellowing stage of flue curing on chemical properties of cured leaves. The wet bulb temperature was automatically controlled between preset high($38^{\circ}C$) and low point ($35^{\circ}C$) everyone hour cyclically during 12 hours after starting luring. As a result, the acceleration of the increase in the chemical properties of cured leaves were observed. As to the chemical properties, there was decreased in citric acid, increased in malic acid of the nonvolatile organic acids and all higher fatty acids content of leaves cured by this method compared with in that of conventional curing method, while a major chemical compounds in relation to aromatic essence of cigarette smoke in essential oil components of lured leaves was mostly higher in this method than those of conventional ones, and it was evaluated that there was decreased in CO, TPM, Tar, and $CO_2$ content of the cigarette smoke comparing to the conventional luring method.

  • PDF

Mechanical Behavior of Cu Nanowire under Cyclic Loading (반복하중을 받는 구리 나노 와이어의 기계적 거동)

  • Lee, Sang-Jin;Cho, Maeng-Hyo
    • Proceedings of the KSME Conference
    • /
    • 2008.11a
    • /
    • pp.1784-1787
    • /
    • 2008
  • Molecular dynamics (MD) simulations are used to analyze behavior of copper nanowires under cyclic loading. The embedded atom method (EAM) potential is employed to represent atomic interaction. Cyclic load is applied in two ways (Forward Tension / Reverse Compression and Forward Compression / Reverse Tension). The results show that dislocations are piled up as a result of plastic deformation during alternate tensile and compressive loading. After cyclic loading with a change of direction, yield stress decreases in consequence of the effect by the dislocation pileups. On the other hand, under FC/RT cyclic load, phase transformation represent associated with mechanical twinning. And copper nanowire can return to almost former undeformed condition during tensile loading at 300K.

  • PDF

Undrained cyclic shear characteristics and crushing behaviour of silica sand

  • Wu, Yang;Hyodo, Masayuki;Aramaki, Noritaka
    • Geomechanics and Engineering
    • /
    • v.14 no.1
    • /
    • pp.1-8
    • /
    • 2018
  • This paper presents an investigation of the liquefaction characteristics and particle crushing of isotropically consolidated silica sand specimens at a wide range of confining pressures varying from 0.1 MPa to 5 MPa during undrained cyclic shearing. Different failure patterns of silica sand specimens subjected to undrained cyclic loading were seen at low and high pressures. The sudden change points with regard to the increasing double amplitude of axial strain with cycle number were identified, regardless of confining pressure. A higher cyclic stress ratio caused the specimen to liquefy at a relatively smaller cycle number, conversely producing a larger relative breakage $B_r$. The rise in confining pressure also resulted in the increasing relative breakage. At a specific cyclic stress ratio, the relative breakage and plastic work increased with the rise in the cyclic loading. Less particle crushing and plastic work consumption was observed for tests terminated after one cyclic loading. Majority of the particle crushing was produced and majority of the plastic work was consumed after the specimen passed through the phase transformation point and until reaching the failure state. The large amount of particle crushing resulted from the high-level strain induced by particle transformation and rotation.