• Steel and Composite Structures
• /
• v.38 no.6
• /
• pp.671-690
• /
• 2021

Seismic responses of RC core wall with two outriggers are investigated in this study. In the models analyzed here, one of the outriggers is fixed at the top of the building and the second is placed at different levels along the height of the system. Each of the systems resulting from the placement of the outrigger at different locations is designed according to the prescriptive codes. The location of the outrigger changes along the height. Linear design of all the structures is accomplished by using prescriptive codes. Buckling restrained braces (BRBs) are used in the outriggers and forward directivity near fault and far fault earthquake record sets are used at maximum considered earthquake (MCE) level. Results from nonlinear time history analysis demonstrate that BRB outriggers can change the seismic responses like force distribution and deformation demand of the RC core-walls over the height and lead to the new plastic hinge arrangement over the core-wall height. Plasticity extension in the RC core wall occurs at the base as well as adjacent to the outrigger levels. Considering the maximum inter-story drift ratio (IDR) demand as an engineering parameter, the best location for the second outrigger is at 0.75H, in which the maximum IDR at the region upper the second outrigger level is approximately equal to the corresponding value in the lower region.

• Earthquakes and Structures
• /
• v.23 no.6
• /
• pp.503-515
• /
• 2022

Global or partial damage to a structure due to the failure of gravity or lateral load-bearing elements is called progressive collapse. In the present study, the alternate load path (ALP) method introduced by GSA and UFC 4-023-03 guidelines is used to evaluate the progressive collapse in special steel moment-resisting frame (SMRF) buildings. It was assumed that the progressive collapse is due to the earthquake force and its effects after the removal of the elements still remain on the structures. Therefore, nonlinear dynamic time history analysis employing 7 earthquake records is used to investigate this phenomenon. Internal and external column removal scenarios are investigated and the stiffness of the connections is changed from semi-rigid to rigid. The results of the analysis performed in the OpenSees program show that the loss of the bearing capacity of an exterior column due to a seismic event and the occurrence of progressive collapse can increase the inter-story drift of the structure with semi-rigid connections by more than 50% and make the structure unable to satisfy the life safety performance level. Furthermore, connection stiffness severely affects the redistribution of forces and moments in the adjacent elements of the removed column.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.14
• /
• pp.5517-5522
• /
• 2014

Oral contraceptive use is the most common type of contraception. More than 300 million women worldwide take oral contraceptives every day. However, there is a concern about the relationship with the incidence of cancer. This analytical retrospective study aimed to investigate the relationship between the incidence of cervical and breast cancers and oral contraceptive use in 128 Iranian patients with cervical cancer, 235 with breast cancer and equal numbers of controls. Data were collected through interviews with an organized set of questions. Details were also extracted from patient files. Data were analyzed using Student's t-test, chi-square and Fisher's exact tests, and Pearson's correlation analysis. The result revealed correlations between both cervical and breast cancers and history of contraceptive pills use. While cervical cancer significantly correlated with duration of use of pills, breast cancer had significant correlations with the type of oral contraceptive and age at first use. No significant relationships were found between the two types of cancer and age at discontinuation of oral contraceptives, patterns of use, and intervals from the last use. The use of oral contraceptives may triple the incidence of cervical cancer and doubles the incidence of breast cancer. Therefore, performing Pap smears every six months and breast cancer screening are warranted for long-term oral contraceptive users.

• Steel and Composite Structures
• /
• v.34 no.4
• /
• pp.487-497
• /
• 2020

During the last few decades, fluid viscous dampers have been significantly improved in terms of performance and reliability. Viscous dampers dissipate the input energy into heat and the increased temperature may damage internal seals of the damper. As a result, thermal compensation is crucial for almost all fluid viscous dampers. In this study, while referring to the main working principles of the recently developed bypass viscous damper in Iran, a comprehensive case study is conducted on a RC building having diagonal braces equipped with such viscous dampers. Experimental results of a small-scale bypass viscous damper is presented and it is shown that the currently available simplified Maxwell models can simulate behavior of the bypass viscous damper with good accuracy. Using a case study, contribution of bypass viscous dampers to seismic behavior of structural and non-structural elements are investigated. A designed procedure is adopted to increase damping ratio of the building from 3% to 15%. In this way, reductions of 25% and 13% in the required concrete and steel rebar materials have been achieved. From nonlinear time history analyses, it is observed that bypass viscous dampers can greatly improve seismic behavior of structural elements and non-structural elements.

• Journal for History of Mathematics
• /
• v.29 no.6
• /
• pp.325-333
• /
• 2016

Chinese Mathematics during the period of Jin (1115-1234) and Yuan (1271-1368) is an integral part of the high achievements of traditional mathematics during the Song (962-1279) and Yuan dynasties, which is another peak in the history of Chinese mathematics, following the footsteps of the high accomplishments during the Warring States period (475-221 BCE), the Western Han (206 BCE-24 ADE), Three Kingdoms (220-280 AD), Jin dynasty (265-420 AD), and Southern and Northern Dynasties (420-589 AD). During the Jin-Yuan period, Quanzhen Taoism was a dominating branch in Taoism. It offered certain political protection and religious comforts to many during troubled times; it also provided a relatively stable environment for intellectual development. Li Ye (1192-1279), Zhu Shijie (fl. late 13th C to early 14th C) and Zhao Youqin (fl. late 13th C to early 14th C), the major actors and contributors to the Jin-Yuan Mathematics achievements, were either heavily influenced by the philosophy of Quanzhen Taoism, or being its followers. In certain Taoist Classics, Li Ye read the records of the relations of a circle and nine right triangles which has been known as Dongyuan jiurong 洞渊九容 of Quanzhen Taoism. These relations made significant contributions in the study of the circles inscribed in a right triangle, the reasoning of which directly led to the birth of the Method of Celestial Elements (Tianyuan shu 天元术), which further developed into the Method of Two Elements (Eryuan shu ⼆元术), the Method of Three Elements (Sanyuan shu 三元术) and the Method of Four Elements (Siyuan shu 四元术).

• Journal of architectural history
• /
• v.27 no.5
• /
• pp.39-48
• /
• 2018

The Agricultural Experimental Organizations[勸業模範場] in Suwon is Korea's first agricultural promotion facility. It was founded in 1906. This study aim to find the area and spatial composition of 勸業模範場. The results are as follows. When it founded, the Agricultural Experimental Organizations was operated centering on the main hall, and then since the pillage of national sovereignty in 1910, it was moved to the jurisdiction of the Japanese Government General of Korea and operated with the addition of the agricultural/forestry school. In 1913, the reductive egg production/distribution was moved from Yongsan branch to Suwon, and reductive egg producing site and female sericulture training office were installed in Suwon. It is supposed that at the time, the Agricultural Experimental Organizations was divided into the main hall-centered area, the Suwon agricultural/forestry school at the south side, and the reductive egg producing site and female sericulture training office even more down south. Since 1920, the agricultural/forestry school came out of the jurisdiction of the Agricultural Experimental Organizations, such that the Agricultural Experimental Organizations was left with only the main hall-centered area and the area with the reductive egg producing site and female sericulture training office. In this study, these two areas are referred to as 'the main hall area' and 'the sericulture area.

• Structural Engineering and Mechanics
• /
• v.67 no.5
• /
• pp.427-437
• /
• 2018

Structural pounding is commonly observed phenomenon during major ground motion, which can cause both structural and architectural damages. To reduce the amount of damage from pounding, the best and effective way is to increase the separation distance. Generally, existing design procedures for determining the separation distance between adjacent buildings subjected to structural pounding are based on approximations of the buildings' peak relative displacement. These procedures are based on unknown safety levels. The aim of this research is to estimate probabilistic separation distance between adjacent structures by considering the variability in the system and uncertainties in the earthquakes characteristics through comprehensive numerical simulations. A large number of models were generated using a robust Monte-Carlo simulation. In total, 6.54 million time-history analyses were performed over the adopted models using an ensemble of 25 ground motions as seismic input within OpenSees software. The results show that a gap size of 50%, 70% and 100% of the considered design code for the structural periods in the range of 0.1-0.5 s, leads to have the probability of pounding about 41.5%, 18% and 5.8%, respectively. Finally, based on the results, two equations are developed for probabilistic determination of needed structural separation distance.

• Structural Engineering and Mechanics
• /
• v.63 no.4
• /
• pp.497-507
• /
• 2017

During recent earthquakes, a significant number of concrete structures suffered extensive damage. Conventional reinforced concrete structures are designed for life-time safety that may see permanent inelastic deformation after severe earthquakes. Hence, there is a need to utilize adequate materials that have the ability to tolerate large deformation and get back to their original shape. Super-elastic shape memory alloy (SMA) is a smart material with unique properties, such as the ability to regain undeformed shape by unloading or heating. In this research, four different stories (three, five, seven and nine) of reinforced concrete (RC) buildings have been studied and subjected to near-field ground motions. For each building, two different types of reinforcement detailing are considered, including (1) conventional steel reinforcement (RC frame) and (2) steel-SMA reinforcement (SMA RC frame), with SMA bars being used at plastic zones of beams and steel bars in other regions. Nonlinear time history analyses have been performed by "SeismoStruct" finite element software. The results indicate that the application of SMA materials in plastic hinge regions of the beams lead to reduction of the residual displacement and consequently post-earthquake repairs. In general, it can be said that shape memory alloy materials reduce structural damage and retrofit costs.

• Earthquakes and Structures
• /
• v.15 no.2
• /
• pp.123-132
• /
• 2018

In this paper the strain energy density (SED) model is used to analyze the seismic behavior of suspen-domes and a new criterion is established for judging the seismic failure based on a characteristic point in the SED model. Firstly, a nonlinear time-history response analysis was carried out using the finite-element package ANSYS for typical suspen-domes subjected to different ground motions. The seismic responses including nodal displacements, ratios of yielding members, strain energy density and structural maximum deformation energy were extracted corresponding to the increasing peak ground acceleration (A). Secondly, the SED sum ($I_d$) was calculated which revealed that the $I_d-A$ curve exhibited a relatively large change (called a characteristic point) at a certain value of A with a very small load increment after the structures entered the elastic-plastic state. Thirdly, a SED criterion is proposed to judge the seismic failure load based on the characteristic point. Subsequently, the case study verifies the characteristic point and the proposed SED criterion. Finally, this paper describes the unity and application of the SED criterion. The SED method may open a new way for structural appraisal and the SED criterion might give a unified criterion for predicting the failure loads of various structures subjected to dynamic loads.

• The Journal of Korean Medical History
• /
• v.19 no.1
• /
• pp.99-110
• /
• 2006

Lee Heon gil (a.k.a. Mongsoo), who was the pioneer of measles treatment in the 18th century, is the 14th generation of the Deokcheongun branch of the Lee family from Jeonju, living from August 25, 1738 (14th year of King Yeongjo) to April 29, 1784 (8th year of King Jeongjo). Under his teacher Lee Cheol hwan, the eldest grandson of Lee Yik, he learned medicine and studied it deeply. His medical service was most remarkable when measles was prevalent in 1775 (51st year of King Yeongjo) at his age of 38. It seems that he wrote books on measles based on his experiences at that time. Lee Heon gil's academic background can be inferred from his relation with Lee Cheol hwan and Jeong Yak yong. Associating with Lee Cheol hwan, he established close relationships with many scholars including the Lee family from Yeoju, who were the descendents of Seongho Lee Yik, and through this fellowship he was influenced directly and indirectly by Seongho Lee Yik. In addition, he maintained close contact with Jeong Yak yong while treating him several times. As Jeong Yak yong was also in close academic association with scholars in the Seongho School and Lee Yik's pupils, he had a philosophical consensus with Lee Heon gil. These academic backgrounds show that the philosophical flow of the Seongho School from Seongho Lee Yik to Jeong Yak yong also reached Lee Heongil.