• Title/Summary/Keyword: historical structures

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A case study for determination of seismic risk priorities in Van (Eastern Turkey)

  • Buyuksarac, Aydin;Isik, Ercan;Harirchian, Ehsan
    • Earthquakes and Structures
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    • v.20 no.4
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    • pp.445-455
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    • 2021
  • Lake Van Basin, located in Eastern Turkey, is worth examining in terms of seismicity due to large-scale losses of property and life during the historical and instrumental period. The most important and largest province in this basin is Van. Recent indicators of the high seismicity risk in the province are damage occurring after devastating earthquakes in 2011 (Mw=7.2 and Mw=5.6) and lastly in 2020 Khoy (Mw=5.9). The seismic hazard analysis for Van and its districts in Eastern Turkey was performed in probabilistic manner. Analyses were made for thirteen different districts in Van. In this study, information is given about the tectonic setting and seismicity of Van. The probabilistic seismic hazard curves were obtained for a probability of exceedance of 2%, 10% and 50% in 50-year periods. The PGA values in the Van province vary from 0.24 g - 0.43 g for earthquakes with repetition period of 475 years. Risk priorities were determined for all districts. The highest risk was calculated for Çaldıran and the lowest risk was found for Gürpınar. Risk priorities for buildings in all districts were also determined via rapid seismic assessment for reinforced-concrete and masonry buildings in this study.

Importance of Convergency Researches for the Appropriate Application of Oil Dispersant (오일분산제 적용을 위한 융합연구의 필요성)

  • Oh, Kyeongseok
    • Journal of the Korea Convergence Society
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    • v.9 no.12
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    • pp.181-187
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    • 2018
  • The historical consumption of oil dispersant was recorded during the protection plans after huge oil spill occurred in the Gulf of Mexico in 2010. As a well-known oil dispersant, Corexit 9500 was used and continuously blamed for the negative effects on environmental ecology. Nevertheless, US EPA still recognizes Corexit 9500 as a future oil dispersant that might be possibly sprayed again to oil slick. In order to develop alternative oil dispersants, it is important to impel the convergency works mainly from microbiologist, ecologist, environmentalist, chemist, and chemical engineer. In this paper, the major components of Corexit 9500 were introduced by chemical structures and physical properties. Presented were also the biodegradable process of dispersed oils and the possible candidates of biosurfactants.

Effectiveness of non-linear fluid viscous dampers in seismically isolated buildings

  • Guler, Elif;Alhan, Cenk
    • Earthquakes and Structures
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    • v.17 no.2
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    • pp.191-204
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    • 2019
  • Near-field earthquake records including long-period high-amplitude velocity pulses can cause large isolation system displacements leading to buckling or rupture of isolators. In such cases, providing supplemental damping in the isolation system has been proposed as a solution. However, it is known that linear viscous dampers can reduce base displacements in case of near-field earthquakes but at the potential expense of increased superstructure response in case of far-field earthquakes. But can non-linear dampers with different levels of non-linearity offer a superior seismic performance? In order to answer this question, the effectiveness of non-linear viscous dampers in reducing isolator displacements and its effects on the superstructure response are investigated. A comparison with linear viscous dampers via time history analysis is done using a base-isolated benchmark building model under historical near-field and far-field earthquake records for a wide range of different levels of non-linearity and supplemental damping. The results show that the non-linearity level and the amount of supplemental damping play important roles in reducing base displacements effectively. Although use of non-linear supplemental dampers may cause superstructure response amplification in case of far-field earthquakes, this negative effect may be avoided or even reduced by using appropriate combinations of non-linearity level and supplemental damping.

Fault Diagnosis Method based on Feature Residual Values for Industrial Rotor Machines

  • Kim, Donghwan;Kim, Younhwan;Jung, Joon-Ha;Sohn, Seokman
    • KEPCO Journal on Electric Power and Energy
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    • v.4 no.2
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    • pp.89-99
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    • 2018
  • Downtime and malfunction of industrial rotor machines represents a crucial cost burden and productivity loss. Fault diagnosis of this equipment has recently been carried out to detect their fault(s) and cause(s) by using fault classification methods. However, these methods are of limited use in detecting rotor faults because of their hypersensitivity to unexpected and different equipment conditions individually. These limitations tend to affect the accuracy of fault classification since fault-related features calculated from vibration signal are moved to other regions or changed. To improve the limited diagnosis accuracy of existing methods, we propose a new approach for fault diagnosis of rotor machines based on the model generated by supervised learning. Our work is based on feature residual values from vibration signals as fault indices. Our diagnostic model is a robust and flexible process that, once learned from historical data only one time, allows it to apply to different target systems without optimization of algorithms. The performance of the proposed method was evaluated by comparing its results with conventional methods for fault diagnosis of rotor machines. The experimental results show that the proposed method can be used to achieve better fault diagnosis, even when applied to systems with different normal-state signals, scales, and structures, without tuning or the use of a complementary algorithm. The effectiveness of the method was assessed by simulation using various rotor machine models.

Effect of various aspects on the seismic performance of a curved bridge with HDR bearings

  • Gupta, Praveen K.;Ghosh, Goutam
    • Earthquakes and Structures
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    • v.19 no.6
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    • pp.427-444
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    • 2020
  • The performance of an isolated horizontally curved continuous bridge with High Damping Rubber (HDR) Bearings has been investigated under seismic loading conditions. The effectiveness of response controls of the bridge by HDR bearings for various aspects viz. variation in ground motion characteristics, multi-directional effect, level of earthquake shaking, varying incidence angle, have been determined. Three recorded ground motions, representative of historical earthquakes along with near-field, far-field and forward directivity effects, have been considered in the study. The efficacy of the bearings with bidirectional effect considering interaction behavior of bearing and pier has also been investigated. Modeling and analysis of the bridge have been done by finite element approach. Sensitivity studies of the bridge response with respect to design parameters of the bearings for the considered ground motions have been performed. The importance of the nonlinearity of HDR bearings along with crucial design parameters has been identified. It has been observed that the HDR bearings performed well in different variations of ground motions, especially for controlling torsional moment. However, the deck displacement has been found to be increased significantly in case of Turkey ground motions, considering forward directivity effect, which needs to be paid more attention from designer point of view.

Regular pattern design using tartan proportions and grid manipulations

  • Wang, Chaoran;Hann, Michael A.
    • The Research Journal of the Costume Culture
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    • v.29 no.6
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    • pp.932-948
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    • 2021
  • Tartan, the woven, checked, and wool textile considered by many to be originally from Scotland, has in fact been in use in a range of forms across numerous cultures and during various historical periods. The characteristic checked feature is due to the assembly of different coloured threads in both warp and weft directions which intersect at 90 degrees in a combination known as a sett. For well over one hundred years, different setts and thus different colour combinations have been associated closely with different geographical regions within Scotland, as well as different clans or families. Tartan-type textiles have reached popularity at various times and those have often been a predicted fashion trend suggested, for example, by contributors to fashion gatherings such as Premier Vision in Paris. Often proposed designs are best considered based on tartan combinations rather than simple reproductions. Promotional terms such as "patched checks" or "textured checks" have been common, and often these have been derived from tartan-type constructions. This paper explores novel pattern design methods by identifying the underlying grid structures and proportions exhibited by various well-known tartan setts. The possibility of pattern development from tartan grids and their manipulations is thus the focus of attention. An insight into the methodology associated with the production of original pattern designs is thus provided.

Civil legal relations in the context of adaptation of civil legislation to the legislation of the EU countries in the digital age

  • Kizlova, Olena;Safonchyk, Oksana;Hlyniana, Kateryna;Mazurenko, Svetlana
    • International Journal of Computer Science & Network Security
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    • v.21 no.12spc
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    • pp.521-525
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    • 2021
  • An essential area is the creation of a single digital market between the EU and Ukraine through information technology. Purpose: to investigate and analyze civil law relations in the field of adaptation of Ukrainian civil law to civil law regulations of the EU. The object of research: Ukrainian civil law and civil law of the EU. The subject of the study is civil law in the context of adaptation of civil law to the legislation of the EU. The following methods of scientific cognition were used during the research: semantic, historical, comparison, analysis and synthesis, generalization. The results of the study show that the harmonization of the legal system of Ukraine with EU law is caused by several goals: successful integration of Ukraine into the EU, legal reforms based on the positive example of EU countries, promoting access of Ukrainian enterprises to the EU market; attracting foreign investment, increasing the welfare of Ukrainian citizens. The adaptation includes three stages, the final of which is the preparation of an expanded program of harmonization of Ukrainian legislation with EU legislation. In the process of adaptation, it is important to take into account the legal history, tradition, features and mentality of Ukraine and before borrowing legal structures to analyze the feasibility of their application in the Ukrainian legal field.

Design wind speed prediction suitable for different parent sample distributions

  • Zhao, Lin;Hu, Xiaonong;Ge, Yaojun
    • Wind and Structures
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    • v.33 no.6
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    • pp.423-435
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    • 2021
  • Although existing algorithms can predict wind speed using historical observation data, for engineering feasibility, most use moment methods and probability density functions to estimate fitted parameters. However, extreme wind speed prediction accuracy for long-term return periods is not always dependent on how the optimized frequency distribution curves are obtained; long-term return periods emphasize general distribution effects rather than marginal distributions, which are closely related to potential extreme values. Moreover, there are different wind speed parent sample types; how to theoretically select the proper extreme value distribution is uncertain. The influence of different sampling time intervals has not been evaluated in the fitting process. To overcome these shortcomings, updated steps are introduced, involving parameter sensitivity analysis for different sampling time intervals. The extreme value prediction accuracy of unknown parent samples is also discussed. Probability analysis of mean wind is combined with estimation of the probability plot correlation coefficient and the maximum likelihood method; an iterative estimation algorithm is proposed. With the updated steps and comparison using a Monte Carlo simulation, a fitting policy suitable for different parent distributions is proposed; its feasibility is demonstrated in extreme wind speed evaluations at Longhua and Chuansha meteorological stations in Shanghai, China.

Conflicts and Resolutions due to the Expansion of Urban Heritage - Focusing on Historic Sites and Hanok Areas in Seoul -

  • Hyun Chul Youn;Seong Lyong Ryoo
    • Architectural research
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    • v.25 no.2
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    • pp.29-40
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    • 2023
  • The purpose of this study is to analyze the conflicts caused by the spatial expansion in two types of urban heritage in Seoul. To explain the national and professional orientation found in each spatial transformation, the study brought the concept of 'historic state' and 'epitome,' thereby examining the operating system of the conflicts. Field observations and stakeholder interviews were performed based on literature and historical research. The study results are as follows. ①In the case of Gwanghwamun and Donuimun, the spatial expansion is to find the historic state of the sites. Gwanghwamun with high national status and substance, conflicts show a pattern that spreads to memory conflicts. Donuimun is relatively unknown and has no substance so that a flexible method of digital restoration was applied. ② In the case of Ikseon-dong and Bukchon hanok, they show heterogeneous spatial expansion. The conflicts in relation to this is caused by the epitome of hanok. In Ikseon-dong, illegal installation of structures(non-epitome) is prevalent, while in Bukchon, there was a process of transferring the new basement(non-epitome) as part of the hanok. ③Conflicts in Gwanghwamun can be coordinated by referring to the digital restoration of Donuimun, and conflicts in Ikseon-dong can be resolved by taking Bukchon as a precedent.

Improvement of hysteretic constitutive model for reinforcements considering buckling

  • Weng Weipeng;Xie Xu;Wang Tianjia;Li Shuailing
    • Earthquakes and Structures
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    • v.25 no.1
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    • pp.57-67
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    • 2023
  • The buckling of longitudinal reinforcements under seismic loading accelerates the degradation of the bearing capacity of reinforced concrete columns. The traditional hysteretic constitutive model of reinforcement, which does not consider buckling, usually overestimates the seismic performance of pier columns. Subsequent researchers have also proposed many models including the buckling effects. However, the accuracy of these hysteretic constitutive models proposed for simulating the buckling behavior is inadequate. In this study, based on their works, the influence of historical events on buckling is considered, the path of the re-tensioning phase is corrected by adjusting the boundary lines, and the positions of the onset buckling point and compressive buckling path during each buckling deformation are corrected by introducing correction parameters and a boundary line. A modified hysteretic constitutive model is obtained, that can more accurately reflect the buckling behavior of reinforcements. Finally, a series of hysteresis tests of reinforcements with different slenderness ratios were then conducted. The experimental results verify the effectiveness of the proposed modified model. Indicating that the modified model can more accurately simulate the equivalent stress-strain relationship of the buckling reinforcement segment.