• Journal of the Korea Concrete Institute
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• v.28 no.5
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• pp.519-525
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• 2016

This paper reports on analyzing the free and restrained shrinkage characteristic of ternary grout used cementitious admixture. In this study, the cementitious admixture was used such as fly ash, ziricania silica fume by combination of expansive additive (a, b) and shrinkage reducing agent. And a number of basic performance tests were conducted to investigate bleeding, volume change, fluidity and compressive strength behavior. According to the results, within appropriate mixing ratio, even the fluidity is not influenced by expansive additive and shrinkage reducing agent, the resistant properties of bleeding, volume change, shrinkage and compressive strength are increased. Comparing with plain grout, the free shrinkage reduced by a minimum of 29% which specimens are added expansive additive and shrinkage reducing agent. The combination of expansive additive a and shrinkage reducing agent is the most effective for reduction of shrinkage. And increasing the mixing ratio of expansive additive and shrinkage reducing agent extended cracking time. Nevertheless, combined addition of expansive additive a 2.0% and shrinkage reducing agent 0.50% has best shrinkage reduction behavior and not appeared cracking. From the above, the mixing ratio of 2.0% of expansive additive a and 0.50% of shrinkage reducing agent is high performance ternary grout for PSC bridge.

• Journal of the Korea Concrete Institute
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• v.21 no.5
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• pp.565-572
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• 2009

In this study, corrosion resistance of palm oil fuel ash (POFA) concrete as a blended concrete is evaluated by using electrochemical technique. The POFA is an industrial byproduct obtained from fuel ash after extracting palm oil from palm-tree. In order to obtain basic material characteristics of the POFA concrete, tests on compressive strength, slump, weight loss, bleeding and expansion ratio were carried out the early-aged POFA concrete. On the other hand, durability characteristics, both chloride penetration and carbonation depth test, were also conducted. Finally, corrosion resistance were evaluated by applying electro-chemical artificial crack healing technique, and the tests on the impressed voltage characteristic, galvanic current and linear polarization resistance. From the experimental results, it was found that long-term strength, bleeding, lower slump ratio, expansion ratio, chloride penetration, carbonation and corrosion resistance were improved by using the POFA due to activated pozzolanic reaction. It can be also mentioned that POFA concrete has a potential to be used as a cementitious binder for green-recycling resources.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2384-2389
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• 2007

The 2nd order response surface method (RSM) has been carried out to get optimum thermal design for enhanced heat transfer on square channel with bleed holes. The RSM was used as an optimization technique with Reynolds-averaged navier-stokes equation. Turbulence model for heat transfer analysis used RNG k-epsilon model. The wall function used enhanced wall function. Numerical local heat transfer coefficients were similar to the experimental tendency. Two design variables such as attack angle of rib (${\alpha}$), rib pitch-to-rib height ratio (p/e) were chosen. Operation condition considered bleeding ratio per bleed hole ($BR_{hole}$). A response surface were constructed by the design variables and operation condition. As a result, adjusted $R^2$ was more than 0.9. Optimization results of various objective function were similar to heat transfer in channel with and without bleed flow. But friction factor was lower than channel without bleed flow.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.3
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• pp.324-331
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• 2016

The present study focuses on the characteristics of a supersonic jet flowing from a rectangular nozzle exit on a flat plate. Flow visualization techniques using schlieren and kerosene-lampblack tracing are utilized to investigate shock reflection structures and boundary-layer separations over a flat plate. Wall pressure measurements are also carried out to quantitatively analyze the flow structures. All observations are repeated for multiple jet flow boundary conditions by varying the flap length and nozzle pressure ratio. The experimental results show that the jet flow structures over the flat plate are highly three-dimensional with strong bleeding flows from the plate sides, and that they are sensitive to plate length and nozzle pressure ratio. A multi-component force measurement device is also utilized to observe the characteristics of the jet flow thrust vectoring over the plate. The maximum thrust deflection angle of the jet is about $8^{\circ}$, demonstrating the applicability of thrust vector control via a flat plate installed at the nozzle exit.

• KCI Concrete Journal
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• v.13 no.2
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• pp.58-66
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• 2001

Recently, polymer-modified mortar has been studied for proposed use on industrial floors as top coat with thin thickness, typically 5~15mm. The purpose of this study is to evaluate basic properties of self-leveling materials using polymer dispersions as kinds of SBR, PAE, St/BA with thin coat (under 3mm). Superplasticizer and thickener have been included in the mixes to reduce bleeding and drying shrinkage as well as to facilitate the workability required. The self-leveling materials using four types of polymer dispersion are prepared with polymer-cement ratio which respectively range from 50% and 75%, and tested for basic characteristics such as unit weight, air content, flow, consistency change and adhesion in tension. From the test results, the self-leveling materials using PAE emulsion at curing age of 28days are almost equal to those of conventional floor using urethane and epoxy resin. The adhesion in tension of self-leveling mortars using SBR latex and PAE emulsion at curing age of 3days is over 17 kgf/cm$^2$(1.67MPa). Consistency change is strongly dependent on the type of polymer dispersion. It is concluded that the self-leveling materials using polymer dispersions can be used in the same manner as conventional floor using thermosetting resin in practical applications, in the selection of polymer dispersions.

• Journal of Chest Surgery
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• v.19 no.1
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• pp.140-147
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• 1986

A clinical study was made on 72 cases of primary lung cancer operated in the department of thoracic & cardiovascular surgery, Kyungpook national university hospital from January 1975 to May 1985. The ratio of male to female was 13.4: I and mean age was 53. Histologically, squamous cell carcinoma comprised 72.2% of 72 operated cases. Before admission to our hospital, the erroneous diagnoses were made at local clinics on the 43 cases[59.7%] and a large percentage of them was diagnosed as pulmonary tuberculosis. And then, total of 56 cases received inadequate treatment or delayed the operation. For the location of the tumor, right to left ratio is 1.2:1 and the right upper lobe was most often involved [23.6%]. Operation was performed on the 72 cases and resection on the 59 cases[8.2%]. Postsurgical staging showed that stage III was found most frequently [59.4%] and T,N,M, was 28% of total cases. Two common surgical complications were bleeding in 7 and acute respiratory failure in 6 cases, and these 6 cases of acute respiratory failure were all died. On the basis of these experiences, we conclude that aggressive effort is needed for the early accurate diagnosis and adequate treatment of lung cancer.

• International Journal of Oral Biology
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• v.48 no.3
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• pp.19-31
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• 2023

Peri-implantitis is a disease affecting the tissue surrounding dental implants, destroying both soft and hard tissues. A total of 2,015 studies were collected by searching items in the National Library of Medicine, including keywords, such as "peri-implantitis," "microbiota," and "microbiome." Of them, 62 studies were screened and considered eligible for analysis. Only 16 studies qualified all criteria mentioned here: "Using PCR methods for microorganism detection," "Suggesting quantified results," "Stating obvious clinical diagnosis criteria ("Bleeding on probing," "Probing pocket depth," "Suppuration," and "Radiographic bone loss")." Only 8 studies were included in the meta-analysis because the others had special issues. Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Aggregatibacter actinomycetemcomitans, Prevotella intermedia, and Epstein-Barr virus were the microbiological subjects of analysis. The odds ratio (OR) between the healthy implants and peri-implantitis were calculated for each microorganism to compare two groups, and the forest plots were suggested as the visual materials. P. gingivalis (1.392 < OR < 2.841), T. forsythia (1.345 < OR < 3.221), T. denticola (2.180 < OR < 5.150), A. actinomycetemcomitans (1.975 < OR < 6.456), P. intermedia (1.245 < OR < 3.612), and Epstein-Barr virus (1.995 < OR < 9.383). The species showed that their 95% confidence interval of odds ratio was higher than 1, indicating that they were detected more frequently in periimplantitis than in healthy implants. Meanwhile, other species, such as Fusobacterium nucleatum and Staphylococcus aureus, were not included in the meta-analysis because the number of studies was insufficient.

• Archives of Plastic Surgery
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• v.41 no.2
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• pp.116-121
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• 2014

Background Understanding risk factors that increase readmission rates may help enhance patient education and set system-wide expectations. We aimed to provide benchmark data on causes and predictors of readmission following inpatient plastic surgery. Methods The 2011 National Surgical Quality Improvement Program dataset was reviewed for patients with both "Plastics" as their recorded surgical specialty and inpatient status. Readmission was tracked through the "Unplanned Readmission" variable. Patient characteristics and outcomes were compared using chi-squared analysis and Student's t-tests for categorical and continuous variables, respectively. Multivariate regression analysis was used for identifying predictors of readmission. Results A total of 3,671 inpatient plastic surgery patients were included. The unplanned readmission rate was 7.11%. Multivariate regression analysis revealed a history of chronic obstructive pulmonary disease (COPD) (odds ratio [OR], 2.01; confidence interval [CI], 1.12- 3.60; P=0.020), previous percutaneous coronary intervention (PCI) (OR, 2.69; CI, 1.21-5.97; P=0.015), hypertension requiring medication (OR, 1.65; CI, 1.22-2.24; P<0.001), bleeding disorders (OR, 1.70; CI, 1.01-2.87; P=0.046), American Society of Anesthesiologists (ASA) class 3 or 4 (OR, 1.57; CI, 1.15-2.15; P=0.004), and obesity (body mass index ${\geq}30$) (OR, 1.43; CI, 1.09-1.88, P=0.011) to be significant predictors of readmission. Conclusions Inpatient plastic surgery has an associated 7.11% unplanned readmission rate. History of COPD, previous PCI, hypertension, ASA class 3 or 4, bleeding disorders, and obesity all proved to be significant risk factors for readmission. These findings will help to benchmark inpatient readmission rates and manage patient and hospital system expectations.

• Journal of Korean Dental Science
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• v.8 no.1
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• pp.10-15
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• 2015

Purpose: The aim of the present study is to assess the importance of proper treatment timing for dental emergency patients by characterizing current patient care in the emergency room. Materials and Methods: A retrospective chart review of 3,211 patients who visited the Chosun University Hospital's dental emergency department (Gwangju, Korea) was conducted from January 1, 2011 to May 31, 2014. Information regarding age, gender, onset date, main causes, and diagnoses were collected and analyzed. The main causes were divided into six categories: assault, household/play, sports, traffic, work, and others. Result: Emergency visits were more common for men (69%), and the ratio of males to females was 2.2:1 On average, the major cause was household/play (49.8%), followed by others (18.9%), traffic (16.6%), assault (9.1%), sports (2.9%), and work (2.6%). The most frequent diagnosis on average was dental trauma with 82.4%, followed by infection (10.7%), others (4.7%), and bleeding (2.2%). Conclusion: The main reasons for visits to the dental emergency department are dental trauma, dental infection, bleeding, and others. The most frequent reason for dental emergency patients to visit the emergency department was dental trauma (82.4%).

• Korean Journal of Clinical Pharmacy
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• v.25 no.4
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• pp.264-272
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• 2015

Background: The over-prescription of acid-suppressive therapy for the provision of stress ulcer prophylaxis (SUP) in hospitalized patients has been identified in a proceeding study. Objective: This study was conducted to evaluate clinicians' beliefs, knowledge and other factors that influence the over-prescribing of SUP in low-risk, non-intensive care unit (non-ICU) patients. Method: A cross-sectional survey consisting of multiple-choice queries and close-ended questions was distributed to healthcare personnel at a major teaching hospital in Korea. Results: More than half of total respondents reported that they would continue SUP following patients discharge from the ICU (77.8%, 43.5%, and 39.7% in the physician, pharmacist, and nurse groups, respectively). Over 55% of physicians would also initiate non-ICU patients on SUP upon hospital admission, and 42.6% of physicians would even continue prophylaxis post hospital discharge. The mean knowledge score regarding SUP indications and side effects was higher in pharmacists compared to physicians and nurses (12.44, 7.40, and 7.28, respectively; p<0.001). High-prescribing behavior was associated with a prescriber's belief that SUP is effective for preventing bleeding (odds ratio 7.40; 95% confidence interval 1.57 to 31.94; p=0.012). Low knowledge score and computerized order set also showed statistically significant association with the overutilization of SUP.