• Education of Primary School Mathematics
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• v.5 no.2
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• pp.111-119
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• 2001

Over the years, the benefits of instructional manipulatives in mathematics education have been verified by classroom practice and educational research. The purpose of this paper is to introduce how the instructional material, specifically, geoboard could be used and integrated in elementary mathematics classroom in order to develop student's mathematical concepts and process in terms of the following areas: (1) Number '||'&'||' Operation : counting, fraction '||'&'||' additio $n_traction/multiplication (2) Geometry : geometric concepts (3) Geometry : symmetry '||'&'||' motion (4) Measurement : area '||'&'||' perimeter (5) Probability '||'&'||' Statistics : table '||'&'||' graph (6) Pattern : finding patterns Further, future study will continue to foster how manipulatives will enhance children's mathematics knowledge and influence on their mathematics performance.

• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2881-2892
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• 2024

Annular flow refers to a special type of two-phase flow pattern in which liquid flows as a thin film at the periphery of a pipe, tube, or conduit, and gas with relatively high velocity flows at the center of the flow section. This gas also includes dispersed liquid droplets. The liquid film flow rate continuously changes inside the tube due to two processes-entrainment and deposition. To determine the liquid holdup, pressure drop, the onset of dryout, and heat transfer characteristics in annular flow, it is important to have proper knowledge of flow characteristics. Especially a better understanding of entrainment fraction is important for the heat transfer and safe operation of two-phase flow systems operating in an annular two-phase flow regime. Therefore, the objective of this work is to develop a computational model for the simulation of the annular two-phase flow regime and assess the various existing models for the entrainment rate. In this work, Computational Fluid Dynamics (CFD) in ANSYS FLUENT has been applied to determine annular flow characteristics such as liquid film thickness, film velocity, entrainment rate, deposition rate, and entrainment fraction for various gas-liquid flow conditions in a vertical upward tube. The gas core with droplets was simulated using the Discrete Phase Model (DPM) which is based on the Eulerian-Lagrangian approach. The Eulerian Wall Film (EWF) model was utilized to simulate liquid film on the tube wall. Three different models of Entrainment rate were implemented and assessed through user-defined functions (UDF) in ANSYS. Finally, entrainment for fully developed flow was determined and compared with the experimental data available in the literature. From the simulations, it was obtained that the Bertodano correlation performed best in predicting entrainment fraction and the results were within the ±30 % limit when compared to experimental data.

• Korean Journal of Adult Nursing
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• v.23 no.3
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• pp.244-254
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• 2011

Purpose: The objective of this study was to evaluate adherence to self-care and identify associated factors in outpatients with Heart Failure (HF). Methods: Using a cross-sectional design, a convenience sample of 249 outpatient clinic patients were recruited at S university hospital. Between October 2009 and December 2009, data were collected through questionnaires and medical record review. Results: The total mean score of adherence to self-care was $18.07{\pm}3.56$ out of a possible 45 points. Among self-care dimensions, adherence to medication and low salt diet was high, while lower adherence was reported in contact with health professionals if symptoms such as weight gain, edema and fatigue were presented. Multivariate analysis adjusted for other socio-demographic and clinical factors showed that disease knowledge related to heart failure (p<.001) and left ventricular ejection fraction (p=.027) were independent predictors of adherence to self-care. These factors explained 23% of total variance in the adherence to self-care. Conclusion: Heart failure patients with higher disease knowledge and those who have good systolic function may be more likely to engage in adherence to self-care than those with lack of disease knowledge and low contractility. Further research is needed to confirm these results and identify other predictors of adherence to self-care.

• The Journal of the Korean bone and joint tumor society
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• v.5 no.1
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• pp.1-8
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• 1999

A single fraction of 50 Gy extracorporeal irradiation, as a modality of limb-sparing operation, has been used to achieve tumor necrosis in osteosarcoma. Although this modality of radiation therapy preserving the mobility of a joint is commonly practiced, the precise knowledge on the radiobiological response of osteosarcoma cell has remained to be elucidated. We therefore observed whether a single high dose irradiation caused apoptosis in osteosarcoma cells and whether the commitment to apoptosis was associated with cell kinetics. We also investigated radiation dose response along the time course for development of apoptosis following single high dose irradiation. The morphologic change in apoptosis was observed by fluorescence with Hoechst 33258 and the degree and the fraction of cells by flow cytometry. Irradiation of osteosarcoma cells with 10, 30 and 50 Gy resulted in chromatin condensation and apoptotic body formation. The degree of apoptosis in osteosarcoma cells was $29.5{\pm}3.56%$, $39.9{\pm}4.83%$ at 24 and 48 hours after 10 Gy irradiation ; $41.1{\pm}3.93%$, $66.9{\pm}5.21%$ at 24 and 48 hours after 30 Gy irradiation ; and $48.0{\pm}3.69%$, $75.6{\pm}4.65%$ at 24 and 48 hours after 50 Gy irradiation. The fraction of cells in cell-cycle kinetic was $39.2{\pm}4.3%$ in G2/M, $22.1{\pm}4.65%$ in G1 at 24 hours after 10 Gy irradiation ; $51.0{\pm}4.3%$ in G2/M, $20.4{\pm}4.7%$ in G1 at 48 hours after 10 Gy irradiation ; $40.3{\pm}3.9%$ in G2/M, $26.1{\pm}4.7%$ in G1 at 24 hours after 30 Gy irradiation ; $59.2{\pm}3.9%$ in G2/M, $5.9{\pm}5.1%$ in G1 at 48 hours after 30 Gy irradiation ; and $44.3{\pm}4.2%$ in G2/M, $21.1{\pm}3.5%$ in G1 at 24 hours after 50 Gy irradiation. The fraction of cells at 48 hours after 50 Gy irradiation could not be observed because of irradiation induced cell death of most of cells. All values for irradiated cells showed accumulation in G2/M phase and reduction in G1 phase, irrespective of irradiation dose. The results suggest that a single fraction of high dose irradiation with 50 Gy results in accumulation of cells at G2/M phase, leading to apoptosis.

• CELLMED
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• v.4 no.1
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• pp.5.1-5.8
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• 2014

Healthcare-associated infection represents a frequent cause of mortality that increases hospital costs. Due to increasing microbial resistance to antibiotics, it is necessary to search for alternative therapies. Consequently, novel alternatives for the control of resistant microorganisms have been studied. Among them, plant antimicrobial protein presents enormous potential, with flowers being a new source of antimicrobial molecules. In this work, the antimicrobial activity of protein-rich fractions from flower tissues from 18 different species was evaluated against several human pathogenic bacteria. The results showed that protein-rich fractions of 12 species were able to control bacterial development. Due its broad inhibition spectrum and high antibacterial activity, the protein-rich fraction of Hibiscus rosa-sinensis was subjected to DEAE-Sepharose chromatography, yielding a retained fraction and a non-retained fraction. The retained fraction inhibits 29.5% of Klebsiella pneumoniae growth, and the non-retained fraction showed 31.5% of growth inhibition against the same bacteria. The protein profile of the chromatography fractions was analyzed by using SDS-PAGE, revealing the presence of two major protein bands in the retained fraction, of 20 and 15 kDa. The results indicate that medicinal plants have the biotechnological potential to increase knowledge about antimicrobial protein structure and action mechanisms, assisting in the rational design of antimicrobial compounds for the development of new antibiotic drugs.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.9 s.240
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• pp.1065-1073
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• 2005

The thermal conductivity of water- and ethylene glycol-based nanofluids containing alumina $(Al_2O_3)$, zinc oxide (ZnO) and titanium dioxide $(TiO_2)$ nanoparticles is measured by varying the particle diameter and volume fraction. The transient hot-wire method using an anodized tantalum wire for electrical insulation is employed for the measurement. The experimental results show that nanofluids have substantially higher thermal conductivities than those of the base fluid and the ratio of thermal conductivity enhancement increases linearly with the volume fraction. It has been found that the ratio of thermal conductivity enhancement increases with decreasing particle size but no empirical or theoretical correlation can explain the particle-size dependence of the thermal conductivity. This work provides, for the first time to our knowledge, a set of consistent experimental data over a wide range of nanofluid conditions and can therefore serve as a basis for developing theoretical models to predict thermal conduction phenomena in nanofluids.

• Korean Journal of Geomatics
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• v.4 no.1
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• pp.1-8
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• 2004

In the middle-resolution remote sensing, the Ground Sampled Distance (GSD) that the detector senses and samples is generally larger than the actual size of the objects (or materials) of interest, and so several objects are embedded in a single pixel. In this case, as it is impossible to detect these objects by the conventional spatial-based image processing techniques, it has to be carried out at sub-pixel level through spectral properties. In this paper, we explain the sub-pixel analysis algorithm, also known as the Linear Spectral Mixing (LSM) model, which has been experimented using the Hyperion data. To find Endmembers used as the prior knowledge for LSM model, we applied the concept of the convex geometry on the two-dimensional scatter plot. The Atmospheric Correction and Minimum Noise Fraction techniques are presented for the pre-processing of Hyperion data. As LSM model is the simplest approach in sub-pixel analysis, the results of our experiment is not good. But we intend to say that the sub-pixel analysis shows much more information in comparison with the image classification.

• ALGAE
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• v.37 no.3
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• pp.227-237
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• 2022

Knowledge on the seaweeds of eastern Sorsogon in the Philippines is uneven. Not only is eastern Sorsogon among the areas of high seaweed diversity but locals there have interacted with seaweeds for ages. Despite seaweeds' assumed importance to Sorsoganon, ethnobotanical records are missing. In this study, we documented the traditional knowledge on seaweed use and determined the rate of knowledge transmission among the locals of eastern Sorsogon. Vernacular names and modes of preparation were given of the 12 identified species bearing culinary and medicinal importance. Ten species were eaten while three were used therapeutically. Based on ethnobotanical indices, Caulerpa chemnitzia ecad turbinata and Gelidiella acerosa were the most important seaweeds. The least cited was Caulerpa racemosa. Our study demonstrated that most of the seaweed resources in eastern Sorsogon remain largely untapped, as the identified ethnotaxa were only about 5% of the total seaweed species diversity reported for the area. The seaweed knowledge in eastern Sorsogon appeared to be homogenous across age groups with primary sources of knowledge biased towards female relatives (mothers and grandmothers) and to children as inheritors. Cessation of seaweed knowledge may come at a potential cost, as a significant fraction of the population did not transmit their knowledge to others. Our study furthered the interest in providing sophisticated resource management recommendations that consider the relationships of traditional and scientific knowledge of seaweed selection and use in eastern Sorsogon and beyond.

• The Mathematical Education
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• v.61 no.3
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• pp.441-456
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• 2022

The purpose of the current study is to report a part of our larger project whose focus is to understand a relationship between students' units coordination and K-12 school mathematics. In particular, in this paper we report how students who exhibit distinct levels of units coordinations used their knowledge of proportion to solve quadratic function problems of the form y = ax². To this end, three 7th grade students all of whom assimiliated whole number problem situations with three levels of units but showed different levels for fraction problems were chosen. We carried out clinical interviews not only to understand their ability to coordinate units but to understand their problem solving process of proportion and the quadratic function problems. The analysis suggest that their abilities to coordinate units influenced their ways to solving proportion problems, and in turn influenced their ways to solve the specific form of quadratic functions. We have finalized our study by discussing how students' ability to construct and coordinate units, their proportion knowledge, and their knowledge associated with expressing the specific type of quadractic functions could be related.

• Korean Chemical Engineering Research
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• v.49 no.1
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• pp.83-88
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• 2011

Holdup characteristics of small bubbles were investigated in a viscous slurry bubble column. The phase holdup of small bubbles was obtained from the knowledge of total bubble(gas) holdup and large bubble holdup, which were measured by mean of static pressure drop method and dual resistivity probe method, respectively. Effects of gas velocity, viscosity of continuous liquid phase and solid fraction in the slurry phase on the small bubble holdup as well as holdups of total bubble(gas) and large bubble in a viscous slurry bubble column. The small bubble holdup increased with increasing gas velocity but decreased with increasing liquid viscosity or solid fraction in the slurry phase. In addition the fraction of small bubble in the total bubble(gas) holdup increased with increasing gas velocity but decreased with increasing liquid viscosity or solid fraction in the slurry phase. It was revealed that the rising velocity of large bubble did not related to the holdup of small bubble in a viscous slurry bubble column.