• Title/Summary/Keyword: Material discontinuity

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Cathodic Protection of Onshore Buried Pipelines Considering Economic Feasibility and Maintenance

  • Choi, Byoung-Yeol;Lee, Sang-Gil;Kim, Jin-Kwang;Oh, Jin-Soo
    • Journal of Advanced Research in Ocean Engineering
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    • v.2 no.4
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    • pp.158-168
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    • 2016
  • During the installation of crude oil or gas pipelines, which pass through onshore buried pipelines or onshore pipeline from subsea pipeline to onshore plant, countermeasures need to be implemented so as to ensure a sufficient design life by protecting the steel pipes against corrosion. This can be achieved through impressed current cathodic protection method for onshore pipelines and through galvanic sacrificial anode corrosion protection method for offshore pipelines. In particular, in the case of impressed current cathodic protection, isolation joint flanges should be used. However, this makes maintenance control difficult with its installation having a negative impact on price. Therefore, in this study, the most suitable methodology for onshore pipeline protection between galvanic sacrificial anode corrosion protection and impressed current cathodic protection method will be introduced. In oil and gas transportation facilities, the media can be carried to the end users via onshore buried and/or offshore pipeline. It is imperative for the field operators, pipeline engineers, and designers to be corrosion conscious as the pipelines would undergo material degradations due to corrosion. The mitigation can be achieved with the introduction of an impressed current cathodic protection method for onshore buried pipelines and a galvanic sacrificial anode corrosion protection method for offshore pipelines. In the case of impressed current cathodic protection, isolation joint flanges should be used to discontinuity. However, this makes maintenance control to be difficult when its installation has a negative impact on the price. In this study, the most suitable corrosion protection technique between galvanic sacrificial anode corrosion protection and impressed current cathodic protection is introduced for (economic life of) onshore buried pipeline.

Shear Load-Transfer Function of Rock-Socketed Drilled Shafts Considering Borehole Roughness (굴착면 거칠기를 고려한 암반 근입 현장타설말뚝의 주면 하중전이함수 제안)

  • Seol, Hoon-Il;Woo, Sang-Yoon;Han, Keun-Taek;Jeong, Sang-Seom
    • Journal of the Korean Geotechnical Society
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    • v.22 no.7
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    • pp.23-35
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    • 2006
  • Shear load transfer characteristics of rock-socketed drilled shafts were analyzed. The constant normal stiffness (CNS) direct shear tests were performed to identify the major influencing factors of shaft resistance, i.e., unconfined compressive strength, borehole roughness, normal stiffness, initial confining stress, and material properties. Based on the CNS tests, shear load transfer function of drilled shafts in rocks is proposed using borehole roughness and the geological strength index (GSI), which indicates discontinuity and surface condition of rock mass in Hoek-Brown criterion (1997). The proposed load-transfer function was verified by the load test results of seven rock-socketed drilled test shafts subjected to axial loads. Through comparisons of the results of load tests, it is found that the load-transfer function by the present study is in good agreement with the general trend observed by in situ measurements, and thus represents a significant improvement in the prediction of load transfer of drilled shafts.

The Internal Deconstruction Trend Expressed in the Works of Jean Paul Gaultier (장 폴 골티에 작품에 나타난 내적 해체경향)

  • 최영옥
    • The Research Journal of the Costume Culture
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    • v.9 no.4
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    • pp.574-591
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    • 2001
  • This study reviews the concept and characteristics of the deconstruction philosophy in order to analyze the major aspects of the fashion world called the deconstruction fashion based on the deconstruction philosophy, and analyzes the works of Jean Paul Gaultier in terms of Derrida's deconstruction theory. The scope of this research is from 1980 to present, and this study fashion on the many kinds of literature on philosophy, aesthetics and literary criticism, and the domestic and international fashion journals and magazines. The deconstructionism is the philosophical theory which denies the traditionally recognized logocentric metaphysical theory and refuses the closed world and pursues the open world, opposing the dichotomic theory which is the deep-rooted tradition of the Western philosophy. The results of analyses centering on the internal deconstruction trend expressed in the works of Jean Paul Gaultier are as follows. 1 The past style combined with the present appears in the form of the entirely new trace, not the past emotion and meaning in Gaultier's works transcending the time and space. 2 Gaultier presents the unconventional intermeaning of meanings, producing various possibilities according to the wearing method of the wearer by layering several clothes. 3. Gaultier breaks from masculinity and femininity in the intertextuality of gender, and decomposes the fixed idea of men's or ladies'wear through the design sharing bisexual text. 4. In the intertextuality of T.P.O., Gaultier presents the problem of how to wear by mixing different items through obscuring the division of the nature of time, space, and purpose. Especially Gaultier can be called the first designer who, worthy of the father of the deconstructionism, has introduced in the fashion making inner wear like outer wear. 5. In the intertextuality of coordination, Gaultier presents a new perspective of coordination through free combination and contrast, raising a question about the man-made harmony criterion and deconstructing the clothes. On the other hand, Gaultier expresses the intertextuality of the material through the heterogeneous combination of the material. 6. The decomposition trend expressed in the many works of Gaultier reflects an open mind presenting a new perspective through the distortion of the form, exaggeration, and break from the existing construction method. 7. The decentering trend in the works of Gaultier is found to deconstruct the Western-dominated elements against the background of subcultural elements, the elements borrowed from the minority race, md the Oriental culture. 8. The discontinuity clothes of Gaultier present the disordered principle of design without the uniform rules, and express the unrestrained freedom without captivation by the preconceived idea through the disruption of the dress and its ornaments just like Gaultier.

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Thermal Bridge and Heat Transfer Analysis for Each Part in Residential Building According to Construction of Wood-based Finishing Material (목질 마감재 구성에 따른 주거용 건축물 부위별 열교 및 전열성능 분석)

  • Seo, Jungki;Jeong, Su-Gwang;Kim, Sumin
    • Journal of the Korean Wood Science and Technology
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    • v.45 no.3
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    • pp.343-359
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    • 2017
  • Many researches and policies have been carried out for saving energy in buildings. However, there are a few studies of thermal characteristics of wood-based materials that have been widely used as structural materials and finishing materials in buildings. In this study, thermal bridging areas were found to investigate thermal performance of residential building using non wood-based materials and wood-based materials. And heat transfer analysis of 16 case studies according to composition of structural materials and finishing materials was conducted. Also in this experiment, Physibel Trisco was used as the heat transfer analysis simulation tool, which conforms to the calculation method of ISO 10211. Analytical modeling was also carried out according to the ISO 10211, and the boundary temperature conditions were set at room temperature $20^{\circ}C$ and outdoor temperature $-11.3^{\circ}C$ (Seoul standard) according to the energy saving design standard in South Korea. Applied structures are classified according to the cases of concrete structure with non wood-based finishing materials, concrete structure with wood-based finishing materials and wood structure. Analyzed building elements were divided into a wall, a roof, an interlayer floor and a bottom floor. As a result, it can be confirmed that the thermal bridge of the concrete structure and wood structure were caused by the geometrical and material causes. In addition, the structural thermal bridge was caused in the discontinuity of the insulation in the concrete structure. Also it was confirmed that the linear heat transfer coefficient of the wall decreases when the wood-based materials are applied to the concrete structure.

Effects of Reduced Sediment Dynamics on Fluvial Channel Geomorphology in the Jiseok River (유사계의 역동성 감소가 지석천 충적하도의 지형변화에 미치는 영향)

  • Ock, Gi-Young;Lee, Sam-Hee
    • Journal of Korea Water Resources Association
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    • v.45 no.5
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    • pp.445-454
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    • 2012
  • The present study aims to investigate the long-term channel morphological changes derived from channelization, embankment and levee construction works in unregulated fluvial channel of the Jiseock River. Analyses of aerial photographs taken past (Year 1966) and recent (Year 2002) showed the temporally remarkable changes in channel planform such as channel shape, bar migration, vegetation encroachment in bar. During the period, the natural single threading changed into braided types together with decreasing sinuosity by 9.2%, increasing vegetation occupied bar ranged 97% of total bars area. Because such channel morphological changes are closely similar to those in dam downstream channels, we assume that both/either flow regime alteration and/or sediment transport discontinuity may be critical for the fixed channel and spread of vegetated bars even in unregulated river without dam reservoir upstream. We found more reduced frequency and magnitude of flooding water level comparing with past, but no significant alteration of inter annual water level variation. Bed material has been coarsened by 4~5 times and the riverbed has been degraded in overall channel but aggraded locally in conjunction reach of tributaries. The results indicates that reduced sediment dynamics in fluvial channel which derived by bed material coarsening, river bed degradation and unbalanced sediment transport capacity between tributary and mainstem can be a causal factor to trigger channel morphological changes even in unregulated rivers.

A Study on Hybrid Expressed in Modern Fashion - Focusing on the End of 1990s - (현대패션에 표현된 하이브리드 경향 연구 - 1990년대 후반을 중심으로 -)

  • 임영자;한윤숙
    • Journal of the Korean Society of Costume
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    • v.51 no.5
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    • pp.113-134
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    • 2001
  • This study was carried out with an objective to prepare the framework of conformity for the 21st century modern fashion, which is interactive with mankind, based on a position that the 21st century contemporary fashion with its amalgamating trend of diversified artistic forms may not be elucidated on a standpoint centering on one certain modality. The hybrid fashion trend of historical modality which provides freedom and satisfaction in creation of an individuals expressive power in expressing true desire of mans inside through man-centered thought of the times has made multifarious motives of the past and present fragmentary. It thus extracts inner divisions and the concept of consolidation through three-dimensional form. Modern fashion is newly interpreted by the material and details of high technologies. and is harmonized by mix and match with various expressions. By having it, it is being expressed together with many types of dresses and ornaments. Modern fashion is being expressed together with many types of dresses and ornaments by new interpretations with the material and details of high technologies and by being harmonized with mix and match with various expressions. The hybrid fashion design trend of regional elements formed by stimuli and contacts of diverse local culture by globalization of network that was achieved by scientific technologies of the contemporary information society has disintegrated varied boundaries in the conventional culture by the latest communication technology-new media on the basis of newly created culture. The fact that regional elements could be expressed as if they were interrelated without each being deprived of originality may be explained with an interpretation on pluralism. The hybrid fashion design trend of cultural aspect, which manifests in the background of scientific technological culture as it transcends the societal-cultural boundaries based on the de-centralization theory of Frederic Jameson, has supplemented the imperfect meanings through conversional correlation with other forms and internal program changes. The middle stratal and polyhedral characteristics are seen as each cultural element is dismantled and reassembled by application of 'multiple-time point expression'. Design forming method is not to bring destruction from outside, but to embrace instability and chaos through radical dismantling of the inside. and to pursue diversity and openness. Thus. it is implemented by an approach that takes the role of design process. In communication of discontinuity, continuity was dismantled through forms of mixing, overlap, perversion, insertion and coincidence.

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Geomorphic Processes of Masung Basin (마성분지(麻城盆地)의 지형생성작용(地形生成作用))

  • Son, Myoung-Won
    • Journal of the Korean association of regional geographers
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    • v.2 no.1
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    • pp.39-49
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    • 1996
  • There is a limestone basin surrounded by the mountains consisted of Paleozoic sedimentary and metamorphic rocks in the Masung, Munkyung city, Kyungsangpook do. The purpose of this paper is to elucidate the geomorphic processes of the gentle hillslopes in the marginal piedmont of Masung basin. To do so, I analyzed deposits over hillslopes and the relation ship between the distance from the divide and the height(above sea level) at the longitudinal profile of the hillslope, and considered interrelation between the distributions of the gentle hillslopes(less than 230m) and lithology. Geomorphic processes of Masung basin are as follow: (1) The depth of deposits over hillslope increases toward downstream of the hillslope. Most gravels within deposits, whose lithology is limestone, are those eroded at the boundary(overthrust fault zone) between the back-mountain and the hillslope. Deposits at the outward margin of hillslope is well sorted. and moderately imbricated. (2) Hillslope at the margin of the basin(160-230m asl) is formed by the action of 'the flow with channel'. At the boundary between the soft rock(limestone; basin floor) and hard rock(sedimentary and metamorphic rock; back-mountain), the relatively weak limestone is eroded to fresh bedrock by the subsequent action of the overland flow, and therefore discontinuity in slope appeared. (3) After hills lopes were formed, sediments(boulders and fine material) produced during dissection in back-mountain buried deposits over hillslope. In conclusion, geomorphic processes of Masung basin is 'differential erosion due to differentiation of lithological hardness' having suggested as geomorphic processes of granitic basin. However it is not 'removal of weathering material due to sheetflow' but 'erosion due to the overland flow with channel'.

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The Analysis of Mesoscale Circulations Characteristics Caused by the Evaporation-Efficiency of Water Retention Pavement (보수성 도로 포장재의 증발효율 변화에 의한 중규모 순환장 특성 분석)

  • Kim, In-Su;Lee, Soon-Hwan;Kim, Hae-Dong;Suh, Young-Chan
    • Journal of the Korean earth science society
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    • v.30 no.6
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    • pp.709-720
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    • 2009
  • Field observation and numerical experiments were conducted to understand the impact of water retention pavement on the surface heat budget and on the regional circulation. The numerical model applied in this study is the atmospheric dynamic model Local Circulation Model (LCM) with two dimensional grid system, and a field observation was carried out under the clear sky and calm conditions of the weather on 19 July 2007. In the field observation, the maximum value of surface temperature on pavement covered with water retention material reached the $41.2^{\circ}C$ at 1430 LST and the values was lower for $16.1^{\circ}C$ than that of asphalt without the material. The Case BET03 assumed to be 0.3 for the surface evaporation efficiency was in good agreement with the observation and its sensible and latent heat fluxes were numerically estimated to be 229 and 227 $W/m^2$, respectively. Results of the numerical experiments demonstrated that the water retention pavement tends to induce the increase of latent heat flux associated with the lower surface temperature and mixing height during the daytime. Discontinuity of latent heat caused by the water retention pavement also tends to promote the development of mesoscale circulation called as land-land breeze or country breeze.

A Study on the Prediction of Elastoplastic Behavior of Carbon Nanotube/Polymer Composites (계면 결합력과 나노튜브의 응집에 따른 나노튜브/고분자 복합재의 탄소성 거동 예측에 대한 연구)

  • Yang, Seunghwa;Yu, Suyoung;Ryu, Junghyun;Cho, Maenghyo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.26 no.6
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    • pp.423-430
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    • 2013
  • In this research, a paramteric study to account for the effect of interfacial strength and nanotube agglomeration on the elastoplastic behavior of carbon nanotube reinforced polypropylene composites is performed. At first, the elastoplastic behavior of nanocomposites is predicted from molecular dynamics(MD) simulations. By combining the MD simulation results with the nonlinear micromechanics model based on the Mori-Tanaka model, a two-step domain decomposition method is applied to inversely identify the elastoplastic behavior of adsorption interphase zone inside nanocomposites. In nonlinear micromechanics model, the secant moduli method combined with field fluctuation method is used to predict the elastoplastic behavior of nanocomposites. To account for the imperfect material interface between nanotube and matrix polymer, displacement discontinuity condition is applied to the micromechanics model. Using the elastoplastic behavior of the adsorption interphase zone obtained from the present study, stress-strain relation of nanocomposites at various interfacial bonding condition and local nanotube agglomeration is predicted from nonlinear micromechanics model with and without the adsorption interphase zone. As a result, it has been found that local nanotube agglomeration is the most important design factor to maximize reinforcing effect of nanotube in elastic and plastic behavior.

Strength Anisotropy through Artificial Weak Plane of Mudstone (인공연약면을 따른 이암의 강도이방성에 관한 연구)

  • Lee, Young-Huy;Jeong, Ghang-Bok
    • Journal of the Korean Geotechnical Society
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    • v.24 no.11
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    • pp.111-120
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    • 2008
  • The characteristic of induced anisotropy is investigated in this study for the Pohang mudstone involving the cut plane discontinuity. The uniaxial and triaxial compression tests are performed for anisotropic rocks with artificial joint to look into anisotropic strength characteristics. Both the uniaxial compressive strength and triaxial compressive strength show the lowest value at the angle of cut plane, ${\beta}=30^{\circ}$ and the shoulder type of anisotropy is obtained. Anisotropy ratio (Rc) in uniaxial compression measures 9.0, whereas Rc=1.29-1.98 in triaxial compression is appeared. A series of analyses are made with the test results to derive the suitable parameter values when it is applied to the Ramamurthy (1985) failure criterion. The result of uniaxial compression test is analyzed by introducing the n-index into Ramamurthy failure criterion. The result shows that, n=l is suitable for ${\beta}=0^{\circ}{\sim}30^{\circ}$ and n=3 is suitable for ${\beta}=30^{\circ}{\sim}90^{\circ}$. To analyze the result of triaxial compression test by Ramamurthy failure criterion, anisotropy ratio in uniaxial compression test is added to Ramamurthy's equation and material constants are estimated by modified Ramamurthy's equation. When these values are applied back to Ramamurthy failure criterion, the predicted values are well fitted to the test results. And strength anisotropy for failure criteria of Jaeger (1960), McLamore & Gray (1967) and Hoek & Brown (1980) are also investigated.