Experimental Study of the Ductility of a Submerged Arc Welded Corner Joint in a High-Performance Steel Built-Up Box Column

Satoshi Yamada,Yuko Shimada,Takanori Ishida,Yuka Matsumoto,Jun Iyama,Hiroumi Shimokawa,Hiroshi Ito,Satoshi Aoyagi 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.5

Submerged arc welding, which is generally used for the corner joint of box-section columns, is a welding process with a high heat input. The influence on the strength and toughness of the heat-affected zone is an important concern, especially when used with a high-performance steel that may be more susceptible to heat input. The ductility of the welded corner joint is one of the important factors to ensure safety against external forces, such as during severe earthquakes. In this study, a series of material and cyclic loading tests of the corner joint comprising SA440C high-performance steel fabricated by submerged arc welding were conducted. The experimental results indicated that the welded corner joint comprising SA440C steel is ductile enough to dissipate input energy caused by the strong ground motion from an earthquake.

International ‘Dialogue’ among Courts in Light of Democracy

Satoshi YAMADA(야마다 사토시) 강원대학교 비교법학연구소 2015 江原法學 Vol.45 No.-

세계화 시대에, 법원은 과거에 가졌던 역할과는 상당히 다른 역할을 채택하고 있다. 몇몇 사람들은 법원이 또한 국제 수준에서 일종의 ‘네트워크’를 형성한다고 지적했다. 여기에서 ‘네트워크’라는 단어는 법원간의 상호작용, 그 중에서도 선례를 따르는 상호작용을 의미한다. 이들은 이를 국제적 ‘대화’라고 부른다. 그러나, 세계화된 법률시스템 내에서 법원의 이러한 상호작용의 역할이 무엇인지가 불확실한 상태로 남아있다. 게다가, 우리는 미국에서 외국 또는 국제적인 법과 선례의 참조를 민주주의의 관점에서 강하게 비판해왔다는 사실을 간과할 수 없다. 이것은 우리가 반드시 민주적 정당성을 고려해야 함을 알려주는 것이다. 이러한 이유로, 본 논문에서는 주로 민주주의의 관점에서 법원간의 국제적 대화의 기능과 한계를 검토한다. 그리고 국내의 법원뿐만 아니라 국제적인 법원 사이의 대화에 대해 논해본다. Von Bogdandy교수는 국제법원이 공권력을 발휘하는 데에는, 특별한 민주적 합법화가 요구된다고 주장한다. 이는 투명성, 공중참여, 국제법의 체계적 해석의 중요성을 제기한다. 또한 본 논문에서는 국내법원의 외국 또는 국제 판결의 참조를 정당화시키고자 한다. 이를 위해, 정당화를 위한 몇 가지 방법을 소개하면서, 그 중에서 Condorcet’s Jury Theorem가 가장 적합함을 밝히고 있다. Condorcet’s Jury Theorem는 국내법원과 국제법원의 판결에 초국가적인 참고를 정당화하는 것과 제한하는 것 모두를 가능하게 하기 때문이다. In our globalized world, courts have come to adopt roles that differ significantly from those typically held in the past. Some have pointed out that courts also create a kind of ‘network’ on the international level. The word ‘network’ here refers to the interaction among courts inter alia mutual in reference to their precedents. Some call this international ‘dialogue’. However, it remains unclear what the role of this network of courts or international dialogue among courts is in our globalized legal system. Furthermore, we cannot overlook the fact that in the United States strong criticism has been levied against reference to foreign or international law and precedents in light of democracy. This teaches us we must take democratic legitimacy into account. For that reason, in this essay we examine the functions and limits of international dialogue among courts mainly in light of democracy. In addition, we discuss the dialogue between not only domestic courts but also international courts. Prof. von Bogdandy insists international courts exercise a kind of public authority and this requires a certain democratic legitimization. We submit the importance of transparency, public participants and systematic interpretation of international law. Here we also try to justify the reference to foreign or international judgments by domestic courts. To that end, we introduce several ways/methods of justification, but find in Condorcet’s Jury Theorem the greatest potential. This theorem offers the possibility of both justifying and limiting the transnational references to judgments by not only domestic courts but also international ones.

Hysteretic Behavior of RHS Columns Under Random Cyclic Loading Considering Local Buckling

Satoshi Yamada,Takanori Ishida,Yu Jiao 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.5

In this paper, a hysteretic model of rectangular hollow section (RHS) columns that includes the deteriorating range caused by local buckling is proposed. The proposed model consists of the skeleton curve, the Bauschinger part that appears before reaching the maximum strength, the strength increasing part of the deteriorating range, and the unloading part. Of these, the skeleton curve, including the deterioration range caused by local buckling, which is considered to be equivalent to the load-deformation relationship under monotonic loading, is obtained through an analytical method. Bi-linear hysteretic models based on experimental results are applied to the Bauschinger part and the strength increasing part. The elastic stiff ness is applied to the unloading part. The proposed model is verifi ed by comparing with experimental results of RHS columns under monotonic and cyclic loading.

Efficacy and Safety of Long-Term Thiopurine Maintenance Treatment in Japanese Patients With Ulcerative Colitis

( Satoshi Yamada ),( Takuya Yoshino ),( Minoru Matsuura ),( Masamichi Kimura ),( Yorimitsu Koshikawa ),( Naoki Minami ),( Takahiko Toyonaga ),( Yusuke Honzawa ),( Hiroshi Nakase ) 대한장연구학회 2015 Intestinal Research Vol.13 No.3

Background/Aims: The long-term clinical outcomes of patients with bio-naive ulcerative colitis (UC) who maintain remission with thiopurine are unclear. The aim of this study was to assess the long-term efficacy and safety of maintenance treatment with thiopurine in UC patients. Methods: This was a retrospective observational cohort analysis conducted at a single center. Between December 1998 and August 2013, 59 of 87 patients with bio-naive UC who achieved remission after induction with treatments other than biologics were enrolled. Remission maintenance with thiopurine was defined as no concomitant treatment needed other than 5-aminosalicylate without relapse. We assessed the remissionmaintenance rate, mucosal healing rate, colectomy-free rate, and treatment safety in UC patients who received thiopurineas maintenance treatment. Results: The 84-month cumulative remission-maintenance and colectomy-free survival rates in the UC patients who were receiving maintenance treatment with thiopurine and 5-aminosalicylate were 43.9% and 88.0%, respectively. Of the 38 patients who underwent colonoscopy during thiopurine maintenance treatment, 23 (60.5%) achieved mucosal healing. Of the 59 patients who achieved clinical remission with thiopurine, 6 patients (10.2%) discontinued the thiopurine therapy because of adverse events. Conclusions: Our study demonstrates the long-term efficacy and safety of thiopurine treatment in patients with bio-naive UC. (Intest Res 2015;13:250-258)

Damage Evaluation Method for Steel Beams Subjected to Cyclic Loading

Satoshi Yamada,Yu Jiao 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.6

Evaluating the cumulative damage of seismic members is an important issue in seismic design. Steel beams are the primary components of seismic moment-resisting frames, wherein the story drift angle and ductility factor with respect to the number of cycles are used as indices of the degree of damage. The former is widely used in the United States and several other countries, whereas the latter is used in Japan. Additionally, these indices are used to express the plastic deformation capacity up to the ultimate state determined by fracture or other failure modes. In this study, an appropriate evaluation method was developed based on the numerical analysis of sub-assemblies for determining the cumulative damage and plastic deformation capacity of steel beams. The analytical results indicate that a unifi ed evaluation is possible based on the relationship between the ductility factor of the beam of each steel grade and the number of cycles to fracture. The proposed method can be used regardless of geometric conditions, except in the case of short-span beams.

A Concise Hysteretic Model of 590 N/mm2 Grade High Performance Steel Considering the Bauschinger Effect

Satoshi Yamada,Yu Jiao,Dong-Seok Lee,Takanori Ishida,Shoichi Kishiki 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.6

A concise hysteretic model of 590 N/mm 2 grade high performance steel SA440 which is used in Japan for building structure is proposed. First, cyclic loading tests of steel components under constant and programmed strain amplitude are performed. Then, hysteresis characteristics are modeled by decomposing the hysteresis curve into the skeleton part, Bauschinger part and the elastically unloading part. The skeleton part and the Bauschinger part are modeled by using the monotonic test result and bi-linear model, respectively. The proposed model is examined by comparing with test results. In addition, a series of member analysis is conducted with proposed model as for the example of application.

A Form of Life/Life of a Form : CHOI, Man-Lin Sculpture One Man Show

Satoshi Yamada 서울대학교 미술대학 1992 造形 FORM Vol.- No.15

The movie recently shown in Japn brining about a sort of sensation entitiled "Why did Daruma go to the east?", which was named after one of the essential questions of Zen Buddhism, "Why did the founder of Zen come from the west?". Showed the beautiful image watching closely to the monks practicing various is disciplines of Zen, wordlessly in the quiet and severd nature. It was an excellent movie which in a way invited the audience to meditation. In it there was an impressive sequence; a child lost in the woods feel off a cliff into the mountain stream. Struggling hard in it for a while, he gave u doing so.

A Concise Hysteretic Model of Structural Steel Considering the Bauschinger Effect

Satoshi Yamada,Yu Jiao 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.3

This study proposes a concise hysteretic model of structural steel that is effective at simulating the mechanical behaviour of steel components. A series of plate element specimens made of SS400 structural steel were tested under diverse cyclic axial strain loadings. The hysteresis loops of the specimens are decomposed into skeleton curves and Bauschinger parts. The hysteretic model, which is composed of the skeleton curve, the Bauschinger part, and the elastic unloading part, is proposed based on the test results. To verify the effectiveness of the proposed hysteretic model, three simply supported beam specimens were tested under cyclic loadings. In addition, numerical analyses of the beams were performed using the proposed hysteretic model. The analytical results were compared with the experimental results, and the overall load-deformation relationships and the local strain histories show a good correspondence.

Plastic Deformation Capacity of Steel Beam-to-Column Connection under Long-duration Earthquake

Yamada, Satoshi,Jiao, Yu,Narihara, Hiroyuki,Yasuda, Satoshi,Hasegawa, Takashi Council on Tall Building and Urban Habitat Korea 2014 International journal of high-rise buildings Vol.3 No.3

Ductile fracture is one of the most common failure modes of steel beam-to-column connections in moment resisting frames. Most proposed evaluation methods of the plastic deformation capacity of a beam until ductile fracture are based on steel beam tests, where the material's yield strength/ratio, the beam's moment gradient, and loading history are the most important parameters. It is impossible and unpractical to cover all these parameters in real tests. Therefore, a new attempt to evaluate a beam's plastic deformation capacity through analysis is introduced in this paper. Another important issue is about the loading histories. Recent years, the effect on the structural component under long-duration ground motion has drawn great attentions. Steel beams tends to experience a large number of loading cycles with small amplitudes during long-duration earthquakes. However, current research often focuses on the beam's behavior under standard incremental loading protocols recommended by respective countries. In this paper, the plastic deformation capacity of steel beams subjected to long duration ground motions was evaluated through analytical methodology.

From Two-To Three-Dimensional MolecularAssemblies for Photoelectric Conversion

Satoshi Nitahara,Sunao Yamada 한국광과학회 2004 Journal of Photosciences Vol.11 No.1