• Steel and Composite Structures
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• v.31 no.5
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• pp.437-452
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• 2019

In this study, in-situ static and dynamic tests of four pre-stressed concrete (PC) track beams with different span lengths and curvatures in a straddle monorail transit system were reported. In the static load tests, the strain and deflection at critical sections of the PC track beams were measured to determine the load bearing capacity and stiffness. The dynamic responses of strain, deflection, acceleration, and displacement at key positions of the PC track beams were measured under different train speeds and train loads to systematically study the dynamic behaviors of the PC track beams. A three-dimensional finite element model of the track beam-vehicle coupled vibration system was established to help understand the dynamic behavior of the system, and the model was verified using the test results. The research results show that the curvature, span length, train speed, and train loads have significant influence on the dynamic responses of the PC track beams. The dynamic performance of the PC track beams in the curve section is susceptible to dynamic loads. Appropriate train loads can effectively reduce the impact of the train on the PC track beam. The PC track beams allow good riding comfort.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.1
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• pp.85-94
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• 2022

To detect anomaly signs of thermal runaway in advance, this study analyzed the signals from various sensors installed in lithium-ion batteries. The thermal runaway mechanism was analyzed, and measurement variables for anomalies of a battery cell were surface temperature, strain, and gas concentration. The changes and characteristics of three variables during the thermal runaway process were analyzed under the abuse environment: the overheat and the overcharge. In experiment, the thermal runaway of the battery proceeded in the initial developing stage, the outgassing stage, and the ignition stage. Analysis from the measured data indicated that the suitable variable to detect all stages of thermal runaway is the surface temperature of the battery, and surface strain is alternative.

• Corrosion Science and Technology
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• v.22 no.6
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• pp.457-465
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• 2023

Irradiation-assisted stress corrosion cracking (IASCC) is one of the main degradation mechanisms of austenitic stainless steels, which are used as reactor internal materials. Slow strain rate testing (SSRT) has been widely applied to evaluate the IASCC initiation characteristics of proton-irradiated tensile specimens. Tensile specimens require low surface roughness for micro-crack observation, and electropolishing is the most important specimen pre-treatment process used for this. In this study, optimal electropolishing conditions were examined through analyzing results of polarization experiments and surface roughness measurements after electropolishing. Corrosion cell and electropolishing equipment were fabricated for polarization tests and electropolishing experiments using SSRT specimens. The experimental parameters were electropolishing time, current density, electrolyte temperature, and stirring speed. The optimal electropolishing conditions for SSRT tensile specimens made of type 316 stainless steel were evaluated as a polishing time of 180 seconds, a current density of 0.15 A/cm², an electrolyte temperature of 60 ℃, and a stirring speed of 200 RPM.

• The Plant Pathology Journal
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• v.40 no.2
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• pp.205-217
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• 2024

Brown rot disease, caused by Monilinia spp., poses a significant threat to pome and stone fruit crops globally, resulting in substantial economic losses during pre- and post-harvest stages. Monilinia fructigena, M. laxa, and M. fructicola are identified as the key agents responsible for brown rot disease. In this study, we employed the amplified fragment length polymorphism (AFLP) method to assess the genetic diversity of 86 strains of Monilinia spp. isolated from major stone fruit cultivation regions in South Korea. Specifically, strains were collected from Chungcheong, Gangwon, Gyeonggi, Gyeongsang, and Jeolla provinces (-do). A comparative analysis of strain characteristics, such as isolation locations, host plants, and responses to chemical fungicides, was conducted. AFLP phylogenetic classification using 20 primer pairs revealed the presence of three distinct groups, with strains from Jeolla province consistently forming a separate group at a high frequency. Furthermore, M. fructicola was divided into three groups by the AFLP pattern. Principal coordinate analysis and PERMANOVA were applied to compare strain information, such as origin, host, and fungicide sensitivity, revealing significant partition patterns for AFLP according to geographic origin and host plants. This study represents the utilization of AFLP methodology to investigate the genetic variability among M. fructicola isolates, highlighting the importance of continuous monitoring and management of variations in the brown rot pathogen.

• Transactions of Materials Processing
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• v.33 no.3
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• pp.185-192
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• 2024

This study examined how varying tempering temperatures affect the susceptibility of Cr-Mo low alloy steels to hydrogen embrittlement. A slow strain-rate test (SSRT) was carried out on the steels electrochemically pre-charged with hydrogen in order to examine the hydrogen embrittlement behavior. The results showed that the hydrogen embrittlement resistance of the Cr-Mo low alloy steels improved with increasing tempering temperature. Thermal desorption analysis (TDA) revealed that diffusible hydrogen content decreased with increasing tempering temperature, accompanied by a slight increase in the peak temperature. This decrease in hydrogen content was likely due to a reduction in dislocation density which served as reversible hydrogen trap sites. These findings underline the significant role of tempering temperature in enhancing the hydrogen embrittlement resistance of Cr-Mo low alloy steels.

• Geotechnical Engineering
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• v.8 no.1
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• pp.19-28
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• 1992

Recently, testing equipment which can run resonant column test altogether with the torsional shear test at the very highly controlled condition was developed at the University of Texas at Austin(U.S.A). With this equipment, the effects of high amplitude pre-straining vibrations on the dynamic properties of clean sands were studied. Tests showed the following results. Low amplitude shear modulus was gradually increased with little void ratio change as the number of high amplitude vibration cycles increased. Variation of volumetric strain with confining pressure for the pre -strained specimen under vibration was smaller than that of fresh specimen. Also the slope of the diagram for shear modulus and confining pressure relationship of the prestrained specimen was smaller than that of fresh specimens. These results agreed well with the analytical results.

• Advances in Computational Design
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• v.2 no.2
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• pp.107-119
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• 2017

The Micro circular diaphragm (MCD) is the mechanical actuator part used in the micro electro-mechanical sensors (MEMS) that combine electrical and mechanical components. These actuators are working under harsh mechanical and thermal conditions, so it is very important to study the mechanical and thermal behaviors of these actuators, in order to do with its function successfully. The objective of this paper is to determine the thermo-mechanical behavior of MCD by developing the traditional bulge test technique to achieve the aims of this work. The specimen is first pre-stressed to ensure that is no initial deflection before applied the loads on diaphragm and then clamped between two plates, a differential pressure (P) and temperature ($T_b$) is leading to a deformation of the MCD. Analytical formulation of developed bulge test technique for MCD thermo-mechanical characterization was established with taking in-to account effect of the residual strength from pre-stressed loading. These makes the plane-strain bulge test ideal for studying the mechanical and thermal behavior of diaphragm in both the elastic and plastic regimes. The differential specimen thickness due to bulge effect to describe the mechanical behavior, and the temperature effect on the MCD material properties to study the thermal behavior under deformation were discussed. A finite element model (FEM) can be extended to apply for investigating the reliability of the proposed bulge test of MCD and compare between the FEM results and another one from analytical calculus. The results show that, the good convergence between the finite element model and analytical model.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.1 no.1
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• pp.105-112
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• 1995

This study was designed to investigate the efficiency of subjective assessment that exams the subjective symptom of patients with back pain at the department of physical therapy. To assess the subjective symptom, we used the pain questionnaire using visual analogue scale (VAS) that was developed by Wang on 1995. Questionnaires were administered to 31 adult patients(male : 11, female : 20) with herniated lumbar disk(13), low back pain(8), myofascial pain syndrom(5), lumbar strain(4), ankylosing spondylitis(1). Mean age was 36.3 ranged from 20 to 65. The results of this study were as follows : 1) In each of 15 subjects, there was a significant decrease in VAS between pre- and post-treatment(p<0.05). 2) Mean VAS of total subjects was $6.26{\pm}2.55$ in pre-treatment, $4.50{\pm}2.47$ in post-treatment (p<0.001). Result of this study was shown efficiency of pain management by subjective assessment. The continuous study is needed for many interesting illue of pain management using VAS.

• Korean Journal Plant Pathology
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• v.14 no.4
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• pp.319-324
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• 1998

Induction of systemic acquired resistance (SAR) against phytophthora blight and pathogenesis-related (PR) protein accumulation by TMV infection in pepper plant (Capsicum annuum cv. Nockwang) were examined to understand the mechanism of the systemic acquired resistance in pepper plant. The zoospore suspension of Phytophthora capsici was inoculated on stem of pepper plant in which TMV-pepper strain had been inoculated on fully expanded upper leaves, and thephytopha blight incidence was examined. Both disease severity and lesion length of phytophthora blight were much smaller in TMV pre-inoculated pepper plant than in uninoculated control plants. The phytophthora blight incidence was decreased about 50% in the TMV pre-inoculated pepper, compared to the uninoculated control plant at 10 days after P. capsici inoculation. Accumulation of PR1 and PR5 proteins in intercellular fluid of TMV-inoculated and uninoculated upper leaves were monitored by immuno-blot with tobacco P1b and PR5a, antibody during induction of SAR. PR1 and PR5 were detected from 24 hours after TMV inoculation in both TMV-inoculated and uninouclated upper leaves, and increased rapidly in TMV-inoculation in uninoculated upper leaves were defoliated. PR5 could be detected upto 20 days after TMV inoculation in uninoculated upper leaves. These results suggest that TMV infection induces SAR against phytophthora blight in pepper plant, and that PR proteins are accumulated very rapidly during induction of SAR and maintained for quite long time in pepper plant.

• Journal of Korean Physical Therapy Science
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• v.2 no.3
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• pp.679-689
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• 1995

This study was designed to investigate the efficiency of subjective assessment that exams the subjective symptom of patients with back pain at the department of physical therapy. To assess the subjective symptom, we used the pain questionnaire using visual analogue scale(VAS) that was developed by Wang on 1995. Questionnaires were administered to 31 adult patients(male : 11, female: 20) with herniated lumbar disk(13), low back pain(8), myofascial pain syndrom(5), lumbar strain(4), ankylosing spondylitis(1). Mean age was 36.3 ranged from 28 to 65. The results of this study were as follows: 1) In each of 15 subjects, there was a significant decrease in VAS between pre-and post-treatment(p < 0.05 -p<0.001). 2) Mean VAS of total subjects was $6.26{\pm}2.55$ in pre-treatment, $4.50{\pm}2.47$ in post-treatment(p < 0.001). The result of this study was shown efficiency of pain management by subjective assessment. The continuous study is needed for many interesting issue of pain management using VAS.