• Smart Structures and Systems
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• v.4 no.1
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• pp.1-17
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• 2008

This study proposes a conceptual framework of in-situ vibration tests and analyses for quality appraisal of non-slender, cast-in-place piles with irregular cross-section configuration. It evaluates a frequency index from vibration recordings to a series of impulse loadings that is related to total soil-resistance forces around a pile, so as to assess if the pile achieves the design requirement in terms of bearing capacity. In particular, in-situ pile-vibration tests in sequential are carried out, in which dropping a weight from different heights generates series impulse loadings with low-to-high amplitudes. The high-amplitude impulse is designed in way that the load will generate equivalent static load that is equal to or larger than the designed bearing capacity of the pile. This study then uses empirical mode decomposition and Hilbert spectral analysis for processing the nonstationary, short-period recordings, so as to single out with accuracy the frequency index. Comparison of the frequency indices identified from the recordings to the series loadings with the design-based one would tell if the total soil resistance force remains linear or nonlinear and subsequently for the quality appraisal of the pile. As an example, this study investigates six data sets collected from the in-situ tests of two piles in Taipu water pump project, Jiangshu Province of China. It concludes that the two piles have the actual axial load capacity higher than the designed bearing capacity. The true bearing capacity of the piles under investigation can be estimated with accuracy if the amplitude of impact loadings is further increased and the analyses are calibrated with the static testing results.

• Environmental Engineering Research
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• v.15 no.2
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• pp.63-70
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• 2010

In this study, the response surface method and experimental design were applied as an alternative to conventional methods for the optimization of coagulation tests. A central composite design, with 4 axial points, 4 factorial points and 5 replicates at the center point were used to build a model for predicting and optimizing the coagulation process. Mathematical model equations were derived by computer simulation programming with a least squares method using the Minitab 15 software. In these equations, the removal efficiencies of turbidity and total organic carbon (TOC) were expressed as second-order functions of two factors, such as alum dose and coagulation pH. Statistical checks (ANOVA table, $R^2$ and $R^2_{adj}$ value, model lack of fit test, and p value) indicated that the model was adequate for representing the experimental data. The p values showed that the quadratic effects of alum dose and coagulation pH were highly significant. In other words, these two factors had an important impact on the turbidity and TOC of treated water. To gain a better understanding of the two variables for optimal coagulation performance, the model was presented as both 3-D response surface and 2-D contour graphs. As a compromise for the simultaneously removal of maximum amounts of 92.5% turbidity and 39.5% TOC, the optimum conditions were found with 44 mg/L alum at pH 7.6. The predicted response from the model showed close agreement with the experimental data ($R^2$ values of 90.63% and 91.43% for turbidity removal and TOC removal, respectively), which demonstrates the effectiveness of this approach in achieving good predictions, while minimizing the number of experiments required.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.1
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• pp.267-274
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• 2013

The impact of income and education level on the clinical and pathologic characteristics, implementation of clinical breast examination (CBE), and treatment patterns of a small population of Chinese female breast cancer patients was studeied in order to provide a theoretical basis and statistical reference for further nationwide research. We included 484 pathologically confirmed female primary breast cancer inpatients of the First Affiliated Hospital of Medical College of Xi'an Jiaotong University from February 2003 to January 2004. All cases were reviewed and relevant information was collected using a designed case report form (CRF). Chisquare tests, rank-sum tests, and Fisher's exact tests were used in the analysis. Our analysis showed that: (1) women in different occupation groups had significant differences in tumor size, pre-operative mammography, surgical options, post-operative estrogen receptor (ER), progestin receptor (PR) and human epidermal growth factor receptor 2 (Her2) status, and post-operative radiotherapy and chemotherapy (P < 0.05); and (2) women with different education levels had statistically significant differences in tumor size, post-operative ER, PR and Her2 status, and post-operative chemotherapy, radiotherapy, and endocrine therapy (P < 0.05). In Xi'an, China, women in low-income occupations or with low education levels are more likely to have advanced tumor stages at presentation, lower implementation rate of clinical breast examination, and less treatment.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.4
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• pp.107-117
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• 2014

This study tests homogeneity and performs multiple comparison analysis among treatment levels of each factor group through t-test by materials and analysis of variance by structural type and service period. For that descriptive statistical analysis is performed for static and dynamic response characteristics and their ratios of calculated versus measured values based on a good many safety assessment reports for bridges. Homogeneity and post hoc test based on descriptive statistical analysis provide the measures for homogeneity identification among comparison groups in addition to the statistical reference values such as central tendency, variation and shape. This study is expected to be valuable for structural integrity assessment and design by comparing the measured and calculated values with the reference values for the homogeneous group identified, which can help the engineers review the adequacy of the values and put the group database to practical use.

• Journal of Pharmaceutical Investigation
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• v.34 no.3
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• pp.229-254
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• 2004

The objective of this study was to scrutinize the rationale of SUPAC-MR and its application in processing postapproval changes to modified release solid oral dosage forms. The types of postapproval changes that were primarily covered with SUPAC-MR included variations in the components and composition, the site of manufacturing, batch size, manufacturing equipment, and manufacturing process. SUPAC-MR defined levels of postapproval changes that the industry might make. Classification of such categories was based on the likelihood of risk occurrence and potential impact of changes upon the safety and efficacy of approved drug products. In most cases, the changes could be classified into 3 levels. It described what chemistry, manufacturing, and control tests should be conducted for each change level. The important tests specified in SUPAC-MR were batch release, stability, in vitro dissolution, and in vivo bioequivalence tests. It then suggested what type of a filing report should be submitted to the FDA for each change level. In general, level 1 changes could be reported in an annual report, whereas level 2 and/or 3 changes could be submitted in changes-being-effected or prior approval supplements. It could be understood that the purpose of SUPAC-MR was to maintain the safety and quality of approved modified release solid oral dosage forms undergoing certain changes. At the same time, it contributed to providing a less burdensome regulatory process with the manufacturers when they wanted to make postapproval changes. European regulatory agencies also implemented SUPAC-like regulations in handling such changes to drug products. Therefore, in this study a recommendation was made for KFDA and the Korean industry to evaluate thoroughly the usefulness of these guidances and regulations in dealing with postapproval changes to modified release solid oral dosage forms.

• Journal of Radiation Protection and Research
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• v.26 no.1
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• pp.35-43
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• 2001

All of sealing capsules to transport a special form radioactive material should be designed and fabricated in accordance with the design criteria prescribed in IAEA standards and domestic regulations. The objective of this study is to demonstrate the safety of a shipping capsule for $^{192}Ir$ special form radioisotope which produced in the HANARO. The safety tests were carried out for the impact, percussion, bending and heat test conditions. And leakage tests were carried out before and after the each test. Also, the safety analyses wert performed using computer codes in order to verify the test results. The capsule showed slight scratches and deformation, and maintained its structural and thermal integrities in all tests without any severe damage or melting. It also met the allowable limits of leakage rate after each test. Therefore, it has been verified that the capsule was designed and fabricated to meet all requirements for the special form.

• Journal of Auto-vehicle Safety Association
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• v.7 no.3
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• pp.14-18
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• 2015

Toughened glass is known to have about four times larger external impact resistance than that of original glass. This study is aimed to verify that ceramic-printed toughened glass does not meet of GTR(Global Technical Regulations) No. 6 and its strength is lower than that of original glass through tests. The tests were conducted on the test pieces of original glass, toughened glass, and ceramic-printed toughened glass from five glass manufacturers. In Test 1, a 227g steel ball was dropped from a height of 2 meters, and damage was checked according to the test method of GTR No. 6. In Test 2, a steel ball was freely dropped from different heights and limited damage height was determined. In the result of Test 1 according to the test method of GTR No. 6, while all five test pieces of toughened glasses were not damaged, all the ceramic-printed toughened glass from the five manufacturers were damaged. In the result of Test 2, none of the five test pieces of toughened glass were damaged by a 10m ball drop, meanwhile, the original glasses were damaged by an average of 3m ball drop. And the results of the tests show that the ceramic-printed toughened glass does not have the features of toughened glass due to its very low strength. Therefore, this study contributes to the safety of consumers by considering the GTR No. 6, and by revising the toughened glass test method.

• Journal of Ocean Engineering and Technology
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• v.30 no.4
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• pp.268-276
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• 2016

This paper presents a study on the crashworthiness of the scaled-down stiffened panels used on a Korean icebreaker. In order to validate the crashworthiness of the panels, this paper provides various mechanical properties such as the results of a CVN test, quasi-static tensile test, and high-speed tensile test at arctic temperatures. Two types of steels (EH32 and FH32) were chosen for the material tests. CVN tests revealed that the two steels were equivalent up to −60℃ in terms of their impact energy absorption capacity. However, the toughness of FH32 was significantly superior to that of EH32. EH32 showed slightly higher flow stresses at all temperature levels compared to FH32. The improvement ratios of the yield strengths, tensile strengths, plastic hardening exponents, etc. for FH32, which were obtained from quasi-static tensile tests, showed an apparent ascending tendency with a decrease in temperature. Dynamic tensile test results were obtained for the two temperatures levels of 20℃ and −60℃ with two plastic strain rate levels of 1 s⁻¹ and 100 s⁻¹. A closed form empirical formula proposed by Choung et al. (2011;2013) was shown to be effective at predicting the flow stress increase due to a strain rate increase.

• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.2982-2989
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• 2021

One of the consequences of the 475 ℃ embrittlement of duplex stainless steels is the reduction of the resistance to localized corrosion. Therefore, the detection of this type of embrittlement before the material exhibits significant loss in toughness, and corrosion resistance is important to ensure the structural integrity of critical components under corrosion threats. In this research, conductivity measurements are performed using the alternating current potential drop (ACPD) technique with using a portable four-point probe as a nondestructive evaluation (NDE) method for detecting the embrittlement in a 2507 (UNS S32750) super duplex stainless steel (SDSS) aged at 475 ℃ from as-received condition to 300 h. The electric conductivity results were compared against two electrochemical tests namely double loop electrochemical potentiokinetic reactivation (DL-EPR) and critical pitting temperature (CPT). Mechanical tests and the microstructure characterized using scanning electron microscopy (SEM) imaging are conducted to track the progress of embrittlement. It is shown that the electric conductivity correlates with the changes in impact energy, microhardness, and CPT corrosion tests result demonstrating the feasibility of the four-point probe as a possible field-deployable method for evaluating the 475 ℃ embrittlement of 2507 SDSS.

• The Journal of Korean Academic Society of Nursing Education
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• v.28 no.2
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• pp.193-203
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• 2022

Purpose: This study explored the mediating role of resilience between post-traumatic stress and emotional exhaustion in nurses during the COVID-19 pandemic. Methods: The data were collected from 193 nurses working at a hospital in Daegu from October 16 to 30, 2020, in the middle of the COVID-19 pandemic. Participants conducted self-reported surveys of post-traumatic stress (Impact of Event Scale-Revised Korean version), emotional exhaustion (Maslach Burnout Inventory), and resilience (Korean Resilience Quotient Test). The data were analyzed using descriptive statistics, frequency, t-tests, Mann-Whitney U tests, Kruskal-Wallis tests, Pearson correlation coefficients, and multiple regression. Mediation analysis was performed using the Baron and Kenny method and Sobel test. Results: The mean scores for post-traumatic stress, resilience, and emotional exhaustion were 16.18±16.18, 183.41±18.29, and 32.64±9.66, respectively. A higher level of post-traumatic stress was associated with lower resilience (r=-.20, p=.004) and with higher emotional exhaustion (r=.33, p<.001). A higher level of resilience was associated with lower emotional exhaustion (r=-.35, p<.001). The resilience was confirmed to have a partial mediating effect in the relationship between post-traumatic stress and emotional exhaustion, verified by the Sobel test (Z=2.31, p=.02). Conclusion: Resilience had a partial mediating effect in the relationship between post-traumatic stress and emotional exhaustion. Thus, nurses should develop individual strengths to reduce emotional exhaustion, and managers should also make efforts to increase the nurses' resilience. It is also necessary to develop and apply a program to strengthen nurses' resilience.