• International journal of steel structures
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• v.18 no.4
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• pp.1139-1152
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• 2018

Many studies on the application of stainless steels as structural materials in buildings and infra-structures have been performed thanks to superior characteristics of corrosion resistance, fire resistance and aesthetic appeal. Experimental investigation to estimate the ultimate strength and fracture mode of the fillet-welded connections of cold-formed austenitic stainless steel (STS304L) with better intergranular corrosion resistance than that of austenitic stainless steel, STS304 commonly used has carried out by authors. Specimens were fabricated to fail by base metal fracture not weld metal fracture with main variables of weld lengths according to loading direction. All specimens showed a block shear fracture mode. In this paper, finite element analysis model was developed to predict the ultimate behaviors of welded connection and its validity was verified through the comparison with test results. Since the block shear behavior of welded connection due to stress triaxiality and shear-lag effects is different from that of bolted connection, stress and strain distributions in the critical path of tensile and shear fracture section were investigated. Test and analysis strengths were compared with those by current design specifications such as AISC, EC3 and existing researcher's proposed equations. In addition, through parametric analysis with extended variables, the conditions of end distance and longitudinal weld length for block shear fracture and tensile fracture were suggested.

• Nuclear Engineering and Technology
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• v.53 no.4
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• pp.1266-1276
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• 2021

The mask parameters of a coded aperture are critical design features when optimizing the performance of a gamma-ray camera. In this paper, experiments and Monte Carlo simulations were performed to derive the minimum detectable activity (MDA) when one seeks a real-time imaging capability. First, the impact of the thickness of the modified uniformly redundant array (MURA) mask on the image quality is quantified, and the imaging of point, line, and surface radiation sources is demonstrated using both cross-correlation (CC) and maximum likelihood expectation maximization (MLEM) methods. Second, the minimum detectable activity is also derived for real-time imaging by altering the factors used in the image quality assessment, consisting of the peak-to-noise ratio (PSNR), the normalized mean square error (NMSE), the spatial resolution (full width at half maximum; FWHM), and the structural similarity (SSIM), all evaluated as a function of energy and mask thickness. Sufficiently sharp images were reconstructed when the mask thickness was approximately 2 cm for a source energy between 30 keV and 1.5 MeV and the minimum detectable activity for real-time imaging was 23.7 MBq at 1 m distance for a 1 s collection time.

• Earthquakes and Structures
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• v.19 no.6
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• pp.445-457
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• 2020

An ultra-high voltage (UHV) transmission system has the advantages of low circuitry loss, high bulk capacity and long-distance transmission capabilities over conventional transmission systems, but it is easier for this system to cross fault rupture zones and become damaged during earthquakes. This paper experimentally and numerically investigates the seismic responses and collapse failure of a UHV transmission tower-line system crossing a fault. A 1:25 reduced-scale model is constructed and tested by using shaking tables to evaluate the influence of the forward-directivity and fling-step effects on the responses of suspension-type towers. Furthermore, the collapse failure tests of the system under specific cross-fault scenarios are carried out. The corresponding finite element (FE) model is established in ABAQUS software and verified based on the Tian-Ma-Qu material model. The results reveal that the seismic responses of the transmission system under the cross-fault scenario are larger than those under the near-fault scenario, and the permanent ground displacements in the fling-step ground motions tend to magnify the seismic responses of the fault-crossing transmission system. The critical collapse peak ground acceleration (PGA), failure mode and weak position determined by the model experiment and numerical simulation are in relatively good agreement. The sequential failure of the members in Segments 4 and 5 leads to the collapse of the entire model, whereas other segments basically remain in the intact state.

• Current Applied Physics
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• v.18 no.11
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• pp.1313-1319
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• 2018

The coil-to-globule behavior of poly{${\gamma}$-2-[2-(2methoxyethoxy)ethoxy]ethoxy-3-caprolactone} (PMEEECL) as a ${\gamma}$-substituted poly (${\varepsilon}$-caprolactone) was investigated via atomistic molecular dynamics (MD) simulation. For this purpose, radius of gyration, end-to-end distance and radial distribution function of the chain in the presence of water were calculated. Consequently, the lower critical solution temperature (LCST) of PMEEECL chain at which the coil-to-globule transition takes place, was determined in each calculated parameter curve. The simulation results indicated that the LCST of PMEEECL was occurred at close to 320 K, which is in a good agreement with previous experimental results. Additionally, the appearance of sudden change in both Flory-Huggins interaction parameter (${\chi}$) and interaction energy between the PMEEECL chain and water molecules at about 320 K confirmed the calculated LCST result. The radial distribution function (RDF) results showed that the affinity of the PMEEECL side chain to water molecules is lower than its backbone.

• Journal of the Society of Naval Architects of Korea
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• v.57 no.5
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• pp.271-277
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• 2020

Recoverability and vulnerability of navy ships under underwater explosion are critical verification factors in the acquisition phase of navy ships. This paper aims to establish numerical analysis techniques for the underwater explosion of navy ships. Doubly Asymptotic Approach (DAA) Equation of Motion (EOM) of primary shock wave and secondary bubble pulse proposed by Geers-Hunter was introduced. Assuming a non-compressive fluid, reference solution of the DAA EOM of Geers-Hunter using Runge-Kutta method was derived for the secondary bubble pulse phase with an assumed charge conditions. Convergence analyses to determine fluid element size were performed, suggesting that the minimum fluid element size for underwater explosion analysis was 0.1 m. The spherical and cylindrical fluid domains were found to be appropriate for the underwater explosion analyses from the fluid domain shape study. Because the element size of 0.1 m was too small to be applied to the actual navy ships, a very slender beam with the square solid section was selected for the study of fluid domain existence effect. The two underwater explosion models with/without fluid domain provided very similar results in terms of the displacement and stress processes.

• Clinics in Shoulder and Elbow
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• v.25 no.3
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• pp.173-181
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• 2022

Background: Healing of the tendon itself is not always related to successful clinical outcomes after rotator cuff repair. It was hypothesized that certain radiologic factors affecting clinical outcomes could exist in case of the retear after arthroscopic rotator cuff repair (ARCR) and the radiologic factors could help predict clinical process. The purpose of this study was to identify the radiologic factors associated with clinical outcomes of the retear after ARCR. Methods: Between January 2012 and December 2019, among patients with sufficient footprint coverage for ARCR, 96 patients with Sugaya classification 4 or higher retear on follow-up magnetic resonance imaging were included. The association between clinical outcomes such as American Shoulder and Elbow Surgeons (ASES) score, Constant score and range of motion and radiologic variables such as initial tear dimension, retear dimension, variance of tear dimension, critical shoulder angle, acromial index, and acromiohumeral distance was analyzed. Results: Preoperatively, the ASES and Constant scores were 59.81±17.02 and 64.30±15.27, respectively. And at the last follow-up, they improved to 81.56±16.29 and 78.62±14.16, respectively (p<0.01 and p<0.01). In multiple linear regression analysis, the variance of the mediolateral dimension of tear had statistically significant association with the ASES and Constant scores (p<0.01 and p=0.01). Conclusions: In patients with the retear after ARCR, the variance in the mediolateral dimension of tear had significantly negative association with the clinical outcomes. This could be considered to be reference as relative criteria and needed more sample and mechanical study.

• Earthquakes and Structures
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• v.23 no.1
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• pp.101-113
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• 2022

A new type of fabricated subway station construction technology can effectively solve these problems. For a new type of metro structure form, it is necessary to clarify its mechanical properties, especially the seismic performance. A soil-structure elastoplastic finite element model is established to perform three-dimensional nonlinear dynamic time-history analysis based on the first fabricated station structure-Yuanjiadian station of Changchun Metro Line 2, China. Firstly, the nonlinear seismic response characteristics of the fabricated and cast-in-place subway stations under different seismic wave excitations are compared and analyzed. Then, a comprehensive analysis of several important parameters that may affect the seismic response of fabricated subway stations is given. The results show that the maximum plastic strain, the interlayer deformation, and the internal force of fabricated station structures are smaller than that of cast-in-place structure, which indicates that the fabricated station structure has good deformation coordination capability and mechanical properties. The seismic responses of fabricated stations were mainly affected by the soil-structure stiffness ratio, the soil inertia effect, and earthquake load conditions rarely mentioned in cast-in-place stations. The critical parameters have little effect on the interlayer deformation but significantly affect the joints' opening distance and contact stress, which can be used as the evaluation index of the seismic performance of fabricated station structures. The presented results can better understand the seismic responses and guide the seismic design of the fabricated station.

• Journal of Korean Physical Therapy Science
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• v.30 no.1
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• pp.23-30
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• 2023

Background: While agility is a critical factor in the performance of sport in the court field, due to the diversity of agility occurrences, it is generally difficult to develop by strength and conditioning training. Previous study reported the correlation with the static balance and agility. However, the correlation between dynamic balance and agility is insufficient. It is necessary to study how static and dynamic balance affect agility respectively, for agility development. Design: Cross sectional correlational study design Methods: Twenty young women participated in the study. Three tests were used : one leg stance(static balance),Y-balance(dynamic balance), side-step(agility). One leg stance measured time, Y-balance measured distance, and side-step measured number of times. Correlation between balance and agility was used by Pearson Correlation. Results: One leg stance and side steps were shown to be not correlated. The Y balance and the side step showed with a moderate positive correlation. Conclusion: Agility is a decisive factor in fast-moving sports performance, which is generally difficult to improve with muscle strength and conditioning training. Since the correlation between dynamic balance and agility was found in this study, the importance of dynamic balance was found to improve agility to promote coordination.

• SUVANNABHUMI
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• v.15 no.2
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• pp.23-55
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• 2023

Just as globalization has many aspects and has developed in various, sometimes contradictory ways with both positive and negative impacts, so too would the reverse process of deglobalization have wide-ranging effects for individuals, communities, and nations. Some parts of globalization began to fray during the coronavirus pandemic (e.g. failing supply chains and disarray in the global shipping industry). Deglobalization would bring about much more significant changes in focusing on local production and consumption, eschewing non-essential flights and international tourism, and replacing personal experience with virtual presence. These impacts would be particularly severe for Vietnam, since its government has placed intensive connectivity with global production at the center of its model for the rapid development on which much of its legitimacy rests and it has joined as many international, multilateral organizations, and protocols as it has been able to do. Through critical analysis of secondary data from a wide range of sources, this paper examines the motivations that people, institutions, and governments might have to pursue deglobalization and then seeks evidence for whether the changes that would bring have started to affect Vietnam. While it is difficult to be too certain about this while the pandemic continues, it is evident that pressures are building in the global north to reconfigure supply chains for greater security, to reduce carbon emissions through regulating long-distance exchanges, and to withdraw from personal contacts. It is argued that a focus on digitalization in economy and society will help to mitigate the negative effects of deglobalization on Vietnam, at least in the medium-term.

• Journal of the Korean Society of Clothing and Textiles
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• v.47 no.1
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• pp.123-136
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• 2023

To develop smart sportswear capable of measuring biometric data, we created a close-fitting pattern using two- and three-dimensional (2D and 3D, respectively) methods. After 3D virtual fitting, the tightness of each pattern was evaluated using image processing of contact points, mesh deviation, and cross-sectional shapes. In contact-point analysis, the 3D pattern showed high rates of contact with the body (84.6% and 93.1% for shirts and pants, respectively). Compared with the 2D pattern, the 3D pattern demonstrated closer contact at the lower chest, upper arm, and thigh regions, where electrocardiography and electromyography were primarily carried out. The overall average gap was also lower in the 3D pattern (5.27 and 4.66 mm in shirts and pants, respectively). In the underbust, waist, thigh circumference, and mid-thigh circumference, the cross-section distance between clothing and body was showed a statistically significant difference and evenly distributed in the 3D pattern, exhibiting more closeness. The tightness and fit of the 3D smart sportswear sensor pattern were successfully evaluated. We believe that this study is critical, as it facilitates the comparison of different patterns through visualization and digitization through 3D virtual fitting.