Influence of Intermetallic Particles on the Corrosion Properties of Extruded ZK60 Mg Alloy Containing Cu

The microstructure and corrosion behavior of the extruded ZK60 Mg alloys with different Cu content were comparatively investigated. The ZK60 alloy had a microstructure consisting of ??-Mg grains with intermetallic MgZn2 and Zn2Zr3 particles. The addition of 1 wt % Cu resulted in the additional presence of CuMgZn particles. In a 0.6 M NaCl solution at 25 ??C, the corrosion rate of the alloy with the added Cu appeared to be about 16% faster than that of the alloy without the addition of Cu. The factors affecting the degraded corrosion resistance of the Cu-added ZK60 alloy are discussed

Simultaneous detection of the nonlinear restoring and excitation of a forced nonlinear oscillation: an integral approach

We address in this article, how to calculate the restoring characteristic and the excitation of a nonlinear forced oscillating system. Under the assumption that the forced nonlinear oscillator has a periodic solution with period, we constructed a system of linear equations by introducing time-dependent multipliers. The periodicity assumption helps simplify the system of linear equations. The stability and uniqueness are also presented for the inverse problem. Numerical testing is conducted to show the effectiveness of our presented methodology.Peer ReviewedPostprint (author's final draft

Statistical Analysis of the Metropolitan Seoul Subway System: Network Structure and Passenger Flows

The Metropolitan Seoul Subway system, consisting of 380 stations, provides the major transportation mode in the metropolitan Seoul area. Focusing on the network structure, we analyze statistical properties and topological consequences of the subway system. We further study the passenger flows on the system, and find that the flow weight distribution exhibits a power-law behavior. In addition, the degree distribution of the spanning tree of the flows also follows a power law.Comment: 10 pages, 4 figure

An Exploratory Study on the Association Between Social Capital and Self-Rated Health of South Korean Women with Disabilities

The purpose of this chapter was to explore the relationship between social capital and self-rated health status as assessed in the activities of the everyday life of South Korean women with disabilities. For this purpose, the authors analyzed the 8th data of the panel survey of employment for the disabled (PSED) that included a sample of 275 women with disabilities who are paid worker. The authors found that working environment, working hours, personal development possibilities, communication-and interpersonal-relationships, the fairness of performance assessment, welfare benefits, training opportunities, and job satisfaction differed significantly in relation to the self-rated health status of women with disabilities. The authors also found that for working hours, communication, and interpersonal relationships, significantly higher self-rated health status was found for satisfied compared to the satisfaction group. For personal development possibilities, welfare benefits, and training opportunities, self-rated health status was significantly higher for the satisfaction group than the dissatisfied group. For fairness of the performance assessment, self-rated health status of the satisfaction group was significantly higher than in the dissatisfied and the normal group. Therefore, in order to improve the self-rated health of South Korean women with disabilities, it is necessary to provide working environment considering their disability characteristics and various training opportunities in their workplace

The Utilization of Traditional Herbal Medicine for Treatment in Traditional Korean Medicine Clinics

A cross-sectional study has been conducted to detect the facts about the use of traditional herbal medicines (THMs) in South Korea. The questionnaire has been adopted from the 2017 National Survey for the usage of traditional Korean medicine (TKM) and consumption of THMs. A total number of 1346 participants have been involved in this study. Results showed that the non-decoction types of herbal medicines, which are mostly used for therapeutic purposes (89.0%), and the decoction types of herbal medicines were not only used for the purpose of treatment of diseases (62.5%) but also health improvement purposes (21.9%). Results presented that decoction types of THMs are used for musculoskeletal diseases (56.0%), digestive diseases (21.3%), and respiratory diseases (6.3%), whereas the non-decoction types of THMs are commonly used in musculoskeletal diseases (55.6%), respiratory diseases (20.5%), and digestive diseases (18.1%). Future studies are highly recommended to detect more details about the medical use of THMs in South Korea

Improved Reliability of FWD Test Results and Correlations with Resilient Modulus

Resilient modulus (MR) is a key factor in the Mechanistic Empirical Pavement Design Guide (MEPDG) which was adopted by INDOT in January 2009. The resilient modulus can be determined in new pavement projects from subgrade soil samples collected at the site. However, for a pavement rehabilitation project, it becomes difficult to obtain soil information, and coring for samples may not be feasible because of traffic. The literature is rich with correlations between the MR of the subgrade obtained in the laboratory with that estimated from FWD tests in the field. However, the review conducted shows very contradictory and inconsistent findings, thus existing correlations seem to apply only to the cases investigated, i.e., they are ad hoc correlations and cannot be generalized. To improve the interpretation of the FWD data and enhance the reliability of the results in Indiana, FWD and GPR tests were performed at five different road construction projects at the same locations where soil samples were collected and tested in the laboratory for resilient modulus. The selected sites included roads with rigid pavement and treated subgrade and flexible pavement with untreated subgrade. The study showed that (1) FWD backcalculation is greatly affected by pavement thickness; (2) GPR can provide actual thicknesses and can identify discrepancies between as-built and design pavement thickness; (3) for flexible pavements, a one-to-one correlation exists between FWD modulus and laboratory resilient modulus values for untreated subgrade soils; (4) MODTAG or ELMOD codes can both be used to estimate the resilient modulus of the subgrade in flexible pavements; (5) for rigid pavements, results of FWD backcalculation analysis using ELMOD or MODTAG greatly overestimate the resilient modulus of the soil, with backcalculated moduli 1.3 to 6 times higher than laboratory results; (6) ELMOD is recommended for routine analysis of FWD data, while MODTAG is recommended for research or to evaluate the quality of the data, when needed