Effect of low-cycle fatigue on the hot ductility of plain carbon steel

In a continuous casting steelmaking operation, the surface of a slab is under a condition that can be characterized as high-temperature, low-cycle fatigue in which the tensile and compressive stress is repeatedly developed. For this reason, for the evaluation of the hot ductility of a slab, considering the fatigue deformation is more feasible before a tensile or compressive test. In this study, the effects of low-cycle fatigue on the hot ductility of steels with a carbon content of 0.06–0.8 wt.% are investigated at various temperatures. For a carbon content of 0.06%, there were no significant differences between the RA values from a simple tensile test and those from a tensile test after fatigue deformation. The tendency of ductility deterioration with fatigue deformation is evident in 0.1 %C steel, and is due to the deformation-induced ferrite film that forms around the prior austenite grain. Conversely, high carbon steel containing 0.8 %C did not show a recovery of hot ductility in a low temperature region, and the specimen on which the tensile was measured after fatigue showed a higher hot ductility in the low temperature region, which is thought to result from the pearlite refinement effects. As the results obtained in this work showed noticeable differences in the hot ductility of carbon steel through the test conditions, it is suggested that for more accurate data, fatigue deformation be adopted in which the temperature range in an unbending operation is determined in the steelmaking factory.     

Separation of oxide inclusions from liquid metal in an applied electrostatic field

It is known that oxide inclusions in liquid metal carry mostly positive charges on their surfaces. In an electrostatic field, therefore, such charged particles suspended in a liquid metal experience forces and accumulate in the region of the negatively charged surface, resulting in the separation of oxide inclusions from the liquid metal. In this study, this principle was experimentally demonstrated for the case of a capacitor cell by the imposition of a d.c. potential on electrodes. The capacitor cell consisted of a dielectric container of Pyrex tube, a high voltage d.c. source, and two electrodes, which were symmetrically attached onto the outer surface of the Pyrex. tube. Experiments were carried out for suspensions of liquid tin/metal oxides, such as SnO₂, WO₃, and PbO under an applied potential of up to 12 kV. All experimental results were in good agreement with the theoretical prediction and showed that the degree of separation was significantly increased with the applied potential.     

Thermodynamic reassessment of the Cd−Zn system

The Cd−Zn system has been thermodynamically reassessed with the CALPHAD method by combining more recent experimental data, in particular the activities of zinc in the liquid phase. A good agreement is obtained between the calculated and experimental thermodynamic parameters as well asphase boundaries.     

How purchase intention consummates purchase behaviour: the stochastic nature of product valuation in electronic commerce

This study challenges the conventional assumption that online customers with high purchase intention routinely move to the purchase stage. To this end, the process of how online customers form purchase intention and behaviour is examined. On the basis of product value distribution (PVD), we propose that the hypothetically expected product value (i.e. PVD average) determines purchase intention, whereas the actual probability of attaining the expected product value (i.e. PVD variance) moderates purchase behaviour. This proposal indicates that the expected product value has significance only when repeated purchase is assumed given that most consumers do not repeatedly purchase the same product in reality. Thus, the actual probability of attaining the expected product value more critically affects customer behaviour than does its expected value. The effectiveness of the research model is verified by conducting a survey on 300 online mall shoppers in Korea. The results confirm model effectiveness.     

A disturbance observer based practical coordinated tracking controller for uncertain heterogeneous multi‐agent systems

This paper presents a coordinated tracking controller for multi‐agent systems. We assume that agents are uncertain, nonidentical, and affected by external disturbances. The information available to the tracking controller is a weighted sum of relative measurements. A coordinated tracking controller based on the disturbance observer, which is known as a robust output feedback controller, is designed so that the disturbances acting on agents are attenuated and at the same time the weighted sum of relative measurements approximately satisfies a differential equation defined by the leader's dynamics, which results in practical coordinated tracking. Systematic design procedures of the controller as well as numerical simulations are provided. Copyright © 2014 John Wiley & Sons, Ltd.     

Retracted: Antecedents and Consequences of Gender Swapping in Online Games

This study examines the reasons underlying gender swapping and its impacts on online gaming behavior. While previous studies considered gender swapping to be an abnormal or rare exception in one's self‐presentation, this study hypothesized that people swap genders as a rational choice based on practical benefits. An online survey was conducted with 318 male players of MMORPGs in Korea. Players swapped gender in games to gain benefits from other players under the condition of anonymity rather than to represent their own gender identity. Men playing female avatars displayed more socially amiable behaviors conventionally characterized as more feminine. Moreover, players were more willing to purchase virtual goods to decorate their gender swapped avatars, mediated by their emotional attachment to their avatar.     

Korean-English bilingual videotext recognition for news headline generation based on a split-merge strategy

This paper deals with Korean-English bilingual videotext recognition for news headline generation. Because videotext contains semantic content information, it can be effectively used for understanding videos. Despite its usefulness, it is a challengeable task to apply text recognition technologies to practical video applications because of the computational complexity and recognition accuracy. In this paper, we propose a novel Korean-English bilingual videotext recognition method to overcome the computational complexity as well as achieve comparable recognition accuracy. To recognize both Korean and English characters effectively, the proposed method employs an elaborate split-merge strategy in which the split segments are merged into characters using the recognition scores. Moreover, it avoids unnecessary computation using geometric features such as squareness and internal gap, and thus its computational overhead is remarkably reduced. Therefore, the proposed method is successfully employed in generating news headlines. The effectiveness and efficiency of the proposed method are verified by extensive experiments on a challenging database containing 51,290 text images (176,884 characters).     

Distinct element method analysis of a retaining wall using a steel frame and fill materials

A technique is developed to clearly establish the shear resistance of a cellular structure, retaining wall composed of a steel frame and fill materials with both continuous and discontinuous characteristics. To overcome the limitation of the existing analysis approach based on continuum mechanics, in which the shear behavior and interaction between the frames and fill material of this type of structure are difficult to describe, this paper introduces displacement incremental analysis into the distinct element method. The results obtained by using the proposed approach are compared with experimental results to verify its accuracy. The results show an internal friction angle of fill materials and overburdening load are major factor determining the shear resistance of a retaining wall with a cellular structure type. From the results of the parametric study on the shear behavior of this type of structure, this paper also proposes a shear resistance moment-shear displacement formula for designing a retaining wall with a cellular structure type.