Stress-Strain Relationship of Ca (

This study examined the stress-strain behavior of 10 calcium hydroxide (Ca(OH)2)-activated Hwangtoh concrete mixes. The volumetric ratio of the coarse aggregate (Vagg) and the water-to-binder (W/B) ratio were selected as the main test variables. Two W/B ratios (25% and 40%) were used and the value of Vagg varied between 0% and 40.0%, and 0% and 46.5% for W/B ratios of 25% and 40%, respectively. The test results demonstrated that the slope of the ascending branch of the stress-strain curve of Ca(OH)2-activated Hwangtoh concrete was smaller, and it displayed a steeper drop in stress in the descending branch, compared with those of ordinary Portland cement (OPC) concrete with the same compressive strength. This trend was more pronounced with the increase in the W/B ratio and decrease in Vagg. Based on the experimental observations, a simple and rational stress-strain model was established mathematically. Furthermore, the modulus of elasticity and strain at peak stress of the Ca(OH)2-activated Hwangtoh concrete were formulated as a function of its compressive strength and Vagg. The proposed stress-strain model predicted the actual behavior accurately, whereas the previous models formulated using OPC concrete data were limited in their applicability to Ca(OH)2-activated Hwangtoh concrete

Mycobacterium seoulense sp. nov., a slowly growing scotochromogenic species

A previously undescribed, slowly growing, scotochromogenic mycobacterium was isolated from a patient with symptomatic pulmonary infection during hsp65 sequence-based identification of Korean clinical isolates. Phenetic characteristics of this strain were generally similar to those of Mycobacterium nebraskense and Mycobacterium scrofulaceum. However, some phenetic characteristics differentiated it from these two species. Its 16S rRNA gene sequences were unique and phylogenetic analysis based on 16S rRNA gene sequences placed the organism in the slowly growing Mycobacterium group close to M. nebraskense and M. scrofulaceum. Its unique mycolic acid profiles and the results of phylogenetic analysis based on two independent alternative chronometer molecules, hsp65 and rpoB, confirmed the taxonomic status of this strain as representing a novel species. These data support the conclusion that this strain represents a novel mycobacterial species, for which the name Mycobacterium seoulense sp. nov. is proposed. The type strain is strain 03-19(T) (=DSM 44998(T)=KCTC 19146(T))

Analysis of Scientific Papers Included in the Sciences Citation Index Expanded Written by South Korean Plastic Surgeons: 2001-2010

BackgroundThe purpose of our study was to analyze scientific papers published by South Korean plastic surgeons in journals included in the Science Citation Index Expanded (SCIE), and to evaluate the publication and research activities of Korean plastic surgeon.MethodsWe conducted a survey of SCIE papers in the field of plastic surgery published by South Korean authors between 2001 and 2010 using Web of Science software. We further analyzed these results according to the number of publications per year, journals, institution, and type of papers. We also compared the total number of citations to published scientific papers. We analyzed the rank of South Korea among other countries in representative journals.ResultsOverall, 667 papers were published by South Korean authors between 2001 and 2010. The number of publications increased dramatically from 2003 (n=31) to 2010 (n=139). Subsequently, the ten most productive Korean medical colleges were identified. All published papers received 2,311 citations and the citation to paper ratio was 3.49. The rank of Korea among other countries in terms of the number of published papers remained in the top 10 during the recent 10 years.ConclusionsPublication output of Korean plastic surgeon over the last 10 years showed a remarkable growth in terms of quantity and quality. Currently, Korea is among the top six countries in representative plastic surgery journals. Korean plastic surgeons have played a central role in this progress, and it is anticipated that they will continue to do so in the future

Analysis of Scientific Papers Included in the

Background The purpose of our study was to analyze scientific papers published by SouthKorean plastic surgeons in journals included in the Science Citation Index Expanded (SCIE),and to evaluate the publication and research activities of Korean plastic surgeon.Methods We conducted a survey of SCIE papers in the field of plastic surgery published bySouth Korean authors between 2001 and 2010 using Web of Science software. We furtheranalyzed these results according to the number of publications per year, journals, institution,and type of papers. We also compared the total number of citations to published scientificpapers. We analyzed the rank of South Korea among other countries in representative journals.Results Overall, 667 papers were published by South Korean authors between 2001 and 2010.The number of publications increased dramatically from 2003 (n=31) to 2010 (n=139).Subsequently, the ten most productive Korean medical colleges were identified. All publishedpapers received 2,311 citations and the citation to paper ratio was 3.49. The rank of Koreaamong other countries in terms of the number of published papers remained in the top 10during the recent 10 years.Conclusions Publication output of Korean plastic surgeon over the last 10 years showed aremarkable growth in terms of quantity and quality. Currently, Korea is among the top sixcountries in representative plastic surgery journals. Korean plastic surgeons have playeda central role in this progress, and it is anticipated that they will continue to do so in thefuture

Serosurveillance for Japanese encephalitis, Akabane, and Aino viruses for Thoroughbred horses in Korea

Recent global warming trends may have a significant impact on vector-borne viral diseases, possibly affecting vector population dynamics and disease transmission. This study measured levels of hemagglutination-inhibition (HI) antibodies against Japanese encephalitis virus (JEV) and neutralizing antibodies against Akabane virus (AKAV) and Aino virus (AINV) for Thoroughbred horses in Korea. Blood samples were collected from 989 racehorses in several provinces, between October 2005 and March 2007. Sera were tested using either an HI assay or a virus neutralization test. Approximately half (49.7%; 492/989) of the horses tested were antibody-positive for JEV. The HI titer against JEV was significantly correlated with racehorse age (p < 0.05). Horses with an HI antibody titer of 1:160 or higher accounted for 3.9% of the animals tested, indicating that vectors transmitting arthropod-borne viruses bit relatively few horses. In contrast, 3.8% (19/497) and 19.5% (97/497) of horse sera collected in March 2007 were positive against AKAV and AINV, respectively. The presence of antibodies against AKAV and AINV may indicate the multiplication of AKAV and AINV in these horses

Cyclic Flexural and Shear Performances of Beam Elements with Longitudinal Glass Fiber Reinforced Polymer (GFRP) Bars in Exterior Beam-Column Connections

The objective of this study is to examine the effect of the poor anchorage length of glass fiber reinforced polymer (GFRP) bars used for longitudinal reinforcement on the flexural and shear performances of beam elements in exterior beam&#8315;column connections made using high-strength materials. Six exterior beam&#8315;column connection specimens were tested under reversal cyclic loads applied at the free-end of the beam. The selected strength categories of materials in the beam element were as follows: 35 MPa and 70 MPa for the design compressive strength of concrete, 400 MPa and 600 MPa for the yield strength of conventional longitudinal steel bars, and 800 MPa for the tensile strength of the GFRP bar. All the longitudinal steel bars of the beams satisfied the minimum requirements of the provisions of ACI 318&#8315;14, whereas all the longitudinal GFRP bars of the beam were linearly anchored into the column section, resulting in poor anchorage length, especially for the beam with the concrete compressive strength of 35 MPa. The flexure-governed beams with GFRP bars exhibited a greater increasing rate in displacement at the pre-peak state and did not display the plastic flow characteristic after the peak load when compared with companion beams with steel bars. The beams with GFRP bars possessed lower diagonal cracking strengths and shear capacities than the companion beams with steel bars although the shear capacities of the beams with GFRP bars could be conservatively predicted using the design equation of ACI 440.1R&#8315;15 provision. The low elastic modulus and elongation capacity of GFRP bars resulted in large displacements and brittle post-peak beam performances. Furthermore, the lack of anchorage length of GFRP bars in exterior beam&#8315;column connection significantly reduced the flexural strength and ductility of the beam element

A Stress-Strain Model for Unconfined Concrete in Compression considering the Size Effect

In this study, a stress-strain model for unconfined concrete with the consideration of the size effect was proposed. The compressive strength model that is based on the function of specimen width and aspect ratio was used for determining the maximum stress. In addition, in stress-strain relationship, a strain at the maximum stress was formulated as a function of compressive strength considering the size effect using the nonlinear regression analysis of data records compiled from a wide variety of specimens. The descending branch after the maximum stress was formulated with the consideration of the effect of decreasing area of fracture energy with the increase in equivalent diameter and aspect ratio of the specimen in the compression damage zone (CDZ) model. The key parameter for the slope of the descending branch was formulated as a function of equivalent diameter and aspect ratio of the specimen, concrete density, and compressive strength of concrete. Consequently, a rational stress-strain model for unconfined concrete was proposed. This model reflects trends that the maximum stress and strain at the peak stress decrease and the slope of the descending branch increases, when the equivalent diameter and aspect ratio of the specimen increase. The proposed model agrees well with the test results, irrespective of the compressive strength of concrete, concrete type, equivalent diameter, and aspect ratio of the specimen