• Applied Chemistry for Engineering
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• v.28 no.1
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• pp.17-22
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• 2017

This review deals with scale-up strategies for optimized chemical processes particularly for micron and submicron products. The method of finding scale-up factors was also introduced for two systems, a system with chemical reaction and a system without chemical reaction. This review is expected to serve as an initial guideline for process engineers who are to scale up their current chemical processes for small products of micron or submicron size.

• Corrosion Science and Technology
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• v.7 no.3
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• pp.139-144
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• 2008

The results of microstructure observations of the $Al_2O_3$ scale formed on a Fe-Cr-Al steel during high temperature oxidation in the $SO_2$ atmosphere are presented. Morphology of the scale has been studied by SEM and TEM techniques. Phase and chemical compositions have been studied by EDX and XRD techniques. The alumina oxide is a primary component of the scale. TEM observations showed that the scale was multilayer. The entire surface of the scale is covered with "whiskers", which look like very thin platelets and have random orientation. The cross section of a sample shows, that the "whiskers" are approximately $2{\mu}m$ high, however the compact scale layer on which they reside is $0.2{\mu}m$ thick. The scale layer was composed mainly of small equiaxial grains and a residual amount of small columnar grains. EDX analysis of the scale surface showed that the any sulfides were found in the formed outer and thin inner scale layer. A phase analysis of the scale formed revealed that it is composed mainly of the $\theta-Al_2O_3$ phase and a residual amount of $\alpha-Al_2O_3$.

• Bulletin of the Korean Chemical Society
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• v.6 no.1
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• pp.19-23
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• 1985

Solvolysis of 1-adamantyl chloride, -bromide and -tosylate have been studied in methanol-acetonitrile mixtures. Rate maxima were found for 1-adamantyl bromide and tosylate at 80-90 % methanol mixtures. The rate maximum observed was interpreted as a result of cooperative enhancement of cation and anion solvation. 1-Adamantyl tosylate had small cation solvation but had extensive anion solvation. It was concluded that the Y scale based on adamantyl tosylate is superior to others since it varies in a wide range especially for weakly ionizing medium.

• Journal of the Korean Society of Combustion
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• v.14 no.3
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• pp.29-36
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• 2009

Simulation is performed to analyze the characteristics of turbulent spray combustion in a diesel engine condition. An extended Conditional Moment Closure (CMC) model is employed to resolve coupling between chemistry and turbulence. Relevant time and length scales and dimensionless numbers are estimated at the tip and the mid spray region during spray development and combustion. The liquid volume fractions are small enough to support validity of droplets assumed as point sources in two-phase flow. The mean scalar dissipation rates (SDR) are lower than the extinction limit to show flame stability throughout the combustion period. The Kolmogorov scales remain relatively constant, while the integral scales increase with decay of turbulence. The chemical time scale decreases abruptly to a small value as ignition occurs with subsequent heat release. The Da and Ka show opposite trends due to variation in the chemical time scale. More work is in progress to identify the spray combustion regimes.

• Journal of Gifted/Talented Education
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• v.20 no.2
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• pp.487-502
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• 2010

The purpose of this study was to examine the effect of SSC(Small-Scale Chemistry) lab program applying to scientifically gifted students' classes. The participants were 15 the middle school scientifically gifted students selected and enrolled in science-gifted education center of university. SSC lab program was applied for 3 month with 5 topics. The research design was one group pretest-posttest design, the data were analyzed using the PASW 18 statistics program. The results of this study were as follows: First, the scientific attitude of scientifically gifted students was improved significantly(p<.01) after applying SSC lab program. Especially, there were significant difference between pre-test and post-test in the scores of cooperativity, spontaneity, perseverance, which were the sub-region of scientific attitude. Second, the creative personality characteristics of scientifically gifted students showed statistically significant improvements(p<.01) after applying SSC lab program. Especially, there was significant difference between pre-test and post-test in the scores of adhesion, which was a sub-region of the creative personality characteristics. Third, there were no significant differences in the science inquiry skills between before and after applying the SSC lab program in the scientifically gifted students' classes(p>.05). The results suggest that SSC Lab program is an effective program in scientifically gifted students' classes.

• Journal of The Korean Association For Science Education
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• v.27 no.9
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• pp.787-795
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• 2007

The purpose of this study was to examine the effects of experimental learning using Small-Scale Chemistry (SSC) on science achievement and scientific attitude of high school students. SSC experiments were devised for 5 experiment themes of high school science textbook. Two classes were chosen from a high school in Busan and adopted into the comparison group and the experimental group; one group with thirty-four students participated in the class with an experimental learning using the SSC (experimental group), and another group with thirty-seven students participated in the class with the traditional learning (comparison group). The major discoveries of this study were as follows: Experimental learning using SSC has shown a significant difference between two groups in the science achievement of the students. Also there was a statistical difference between these two groups in the test which was conducted after a month to find out the durability of the experiment. Thus, the learning using SSC is assumed to be durable. Furthermore, there was a significant difference in scientific attitude between the two groups. It seemed that the learning using SSC had a good influence on fanning students' scientific attitude. In conclusion, an experimental learning using SSC has a positive effect on scientific achievement, the durability and scientific attitude of the students. We hope to develop suitable and various experimental learning materials using the SSC program that can be adopted in the classroom soon.

• Journal of The Korean Association For Science Education
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• v.29 no.2
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• pp.179-192
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• 2009

The purpose of this study was to examine the effects of Small-Scale Chemistry (below SSC) Lab Program with respect to students' extroversions and introversions. For this study, an SSC Lab Program was developed on the basis of analyzing the chemistry part of the high school science textbook in the 7th curriculum. The experimental group received SSC experiment lessons, and the comparison group received traditional experiment lessons based on textbook for 5 class periods. Afterwards, students were grouped into extrovert and introvert according to their personality test scores, the differences between the two groups were investigated using 2-way ANCOVA. Prior to the instructions, three test regarding the scientific attitude and academic self-efficacy were administered. After the instructions, the scientific attitude, academic self-efficacy, and students' perceptions on SSC Lab Program were examined. The scores in mid-term and end-of-term science exams were used as pre-test and post-test science achievement scores, respectively. Two-way ANCOVA results revealed that there were effects in the score of the academic achievement score, but there was no interactive effect between extroversion/introversion and treatment. In addition, a significant interactive effect was found in the scientific attitude, but there was no significant main effect. It was interpreted that extrovert students had many opportunities in SSC experiment classes and were able to experiment with initiative, but introverts would feel the responsibility and the pressure owing to the small group experiment. There were no main and interactive effects in the score of the academic self-efficacy test. Survey of students' perceptions on SSC Lab Program revealed that both over 90% extrovert and introvert students showed very positive perceptions in 'three-membered small group composition,' 'understanding,' and 'convenience' items. It was found to be a very different perception between extrovert and introvert students in 'comparing result with other students' item.

• Steel and Composite Structures
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• v.31 no.5
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• pp.517-527
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• 2019

To move forward in large steps rather than in small increments, the community would benefit from a systematic and comprehensive database of multi-scale composites and measured properties, driven by comprehensive studies with a full range of types of fiber-reinforced polymers. The multi-scale hierarchy is a promising chemical approach that provides superior performance in synergistically integrated microstructured fibers and nanostructured materials in composite applications. Achieving high-efficiency thermal conductivity and mechanical properties with a simple surface treatment on single-walled carbon nanotubes (SWCNTs) is important for multi-scale composites. The main purpose of the project is to introduce ozone-treated SWCNTs between an epoxy matrix and basalt fibers to improve mechanical properties and thermal conductivity by enhancing dispersion and interfacial adhesion. The obvious advantage of this approach is that it is much more effective than the conventional approach at improving the thermal conductivity and mechanical properties of materials under an equivalent load, and shows particularly significant improvement for high loads. Such an effort could accelerate the conversion of multi-scale composites into high performance materials and provide more rational guidance and fundamental understanding towards realizing the theoretical limits of thermal and mechanical properties.

• Journal of Science Education
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• v.34 no.2
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• pp.291-305
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• 2010

The aim of this study was to survey the perceptions of the elementary school teachers on the smallscale chemistry(SSC) following its training session. The teachers participating in the survey were 266 teachers in the Gyeongnam province. They were given a questionnaire that focused on the nine areas of the SSC: Needs for the teacher training and its application, its benefits, issues of safety and danger as well as treatment of environmental pollution, its economic efficiency and the development of investigative skills. The designed questionnaire was checked by an authority, and the responses to each question were tallied and analyzed. The results are as follows. The biggest problems of the traditional experimental methods as rated by the teachers were, in the order of importance, the preparation time, the legal liability of teachers for the safety and accidents, financial issues, disposal of the experimental wastes and the lack of relevant data. Since most of the teachers had not experienced the SSC lab programs in the field, they responded positively to the questions of need for its introduction and training. The implementation of the experimental SSC lab programs should proceed in the following order: introduction into the textbook, teacher training program, after-school education and the invitation of instructors. The most useful materials for the SSC program were CDs, videos, books and various printed materials, in that order. The responses regarding benefits of the SSC program included its simplicity, convenience, time savings, diversity, qualitative and quantitative aspects, integration into the regular class and use of toys. In particular, the teachers mentioned the increased safety due to the small amount of experimental reagents needed and the durability of plastic instruments. The familarity from the use of everyday tools as well as easy access to and the low-cost of the instruments were other important benefits. The teachers in general rated the educational content of the program highly, but many also found it to be average. Some pointed out the lack of sufficient discussion due to the individual or pair groupings as a potential shortcoming. The potential for development of problem solving ability and improvement of skills was rated positively. The number of teacher who rated the development of creativity positively was just over the half. As for the area of improving investigative skills, many found its assessment difficult and confusing because of the lack of its systemic definition and categorization. Based on the findings of this study, I would like to recommend the application and a wider dissemination of the small-scale chemistry lab program into the elementary school science curriculum.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.1092-1095
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• 1999

The well-known mixed-acid process for the aromatic nitration requires subsequent separation of spent acid, mainly dilute sulfuric acid. A novel nitration process using $HNO_3-NO_2-O_3$ was tested in a small pilot scale with 3 mol of p-nitrotoluene. Nitrogen dioxide(14.3 mol) was added three times in parts into the solution of p-nitrotoluene and $HNO_3$(6 mol) in dichloroethane. The nitration proceeded to more than 97% conversion within 5.5 h using 0.871 mol/h of ozone. As a clean process of aromatic nitration, this method is expected to replace the present process which causes the environmental problems.