• Explosives and Blasting
• /
• v.41 no.4
• /
• pp.9-16
• /
• 2023

To compare the global warming impact of the TBM and NATM method, which are representative tunnel excavation methods, a life cycle assessment was performed for each method. Life cycle assessment should compare the sum of carbon emissions by considering the pre-manufacturing stage, product manufacturing stage, usage stage, and disposal stage. However, access to TBM (Tunnel Boring Machine) manufacturing and disposal data is limited, so I had no choice but to focus on the analysis for the usage stage. In general, carbon emissions during the pre-product manufacturing stage and product manufacturing stage often exceed 90% of carbon emissions throughout the entire process. Therefore, since it is difficult to achieve the analysis goal only by comparing the usage stage, the analysis scope was expanded, and carbon emissions for the process were calculated for the NATM method with access to manufacturing data. As a result of comparing the relative impact on global warming, the carbon emissions of the TBM method were found to be higher than those of the NATM method even though TBM method was only considered for the usage stage. So there it is, the NATM method can be seen as environmentally friendly in the future when considering the impact of climate change (global warming), which has recently attracted attention among environmental impact fields.

• Journal of The Korean Association For Science Education
• /
• v.28 no.4
• /
• pp.316-330
• /
• 2008

During the past two decades or so, science (or scientific or scientific & technological) culture has become one of the main themes not only of policy makers but also of science educators. Although, the idea of science culture has been taken as a desirable goal, there is little agreement about what it means and how to measure it. Particularly in Korea, there has been a rapid growth of science culture projects and programs, either by governmental or non-governmental, but with little systemic monitoring and evaluation for its practice. The purpose of this study is, thus, to explore a model of measuring science culture and develop a comprehensive indicator system for it. We reviewed many literatures on definitions of science culture and the surveys for related terms, particularly, of recent national and international surveys (e.g. US Science and Engineering Indicators, Eurobarometer, Japanese Science and Technology Indicators). Based on this review, a model for science culture is proposed and then used to define the Science Culture Indicators (SCI). This model encompasses two dimensions(i.e. individual and social), which are further divided into two aspects (i.e. potential and practice). Each dimension is expected to represent citizen literacy of and national infrastructure of science culture respectively. Each category in this $2{\times}2$ matrix is further divided into several sub-categories. The discussion concerning how the model and the indicators can be used to check the states of science culture at social as well as individual levels will be given with some concrete examples, such as indicators particularly related to science education.

• Journal of The Korean Association For Science Education
• /
• v.26 no.7
• /
• pp.856-869
• /
• 2006

J. J. Schwab is usually considered as the founder of the concept of scientific enquiry, perhaps the most important key word of science education of the 20th century. Mainly through the method of literature review, this study reappraises Schwab's life as a science educator as well as a curriculum scholar, and his ideas concerning several important issues about science and science education. Like other eminent science educators, before the 1950s, who were originally talented scientists but later became engaged in educational activities, Schwab were trained and known as a genetic scientist, but later he concentrated on university reform, curriculum studies and science education. His academic interest was very diverse across different disciplines, from biology and science in general to history, philosophy and education. The essence of his theory of scientific enquiry was 'to teach science as science', and the best way to do it was 'to teach science as enquiry'. With enquiry, however, he tried to deliver some important but differentiated meanings, for example by distinguishing 'science as enquiry' and 'teaching as enquiry', and 'static enquiry' and 'fluid enquiry'. Scientific enquiry was the core concept upon which many of his ideas concerning science education and education in general were based, such as the diversity of science, textbooks, curriculum and roles of teachers. In summary, Schwab can be characterized as a rational reformist of science education, who tried to identify the very nature and goals of the discipline and to bring its substantial changes with concrete and practical guidelines. Nevertheless, some of his ideas, like the diversity of science and conceptual invention, have been handed down by his followers frequently with considerable distortion.

• Journal of Korean Elementary Science Education
• /
• v.43 no.2
• /
• pp.337-352
• /
• 2024

This study develops an informal science education program based on a creative design for the promotion of participation and action and explores the validity and effectiveness of the program. The program consists of three mini-projects, namely, The Martian: Surviving from the Mars, So Good to Have Seonjeongneung, and Designing a Sunshine Restaurant, with distinct topics focusing on the localization and contextualization of the region in which the program was implemented to encourage students' participation and action. The researchers selected three topics for each mini-project through discussions and revisions. The program is designed for 42 lessons across the three mini-projects and offers a presentation session in which students present their learnings from the program, constructed to facilitate personal contextualization. Participants included 15 elementary school students from Grades 5 and 6 who took surveys before and after the program. The pre-post surveys comprised two dimensions, 'Participation and Action' and 'Positive Experience about Science,' to examine the effectiveness of the program. At the end of the survey, we added a self-descriptive question that allows students to freely write down their feelings and thoughts. We checked the students' thoughts. The effectiveness of the program was illustrated by the largest increase in the "safe society" category, whereas there was little increase in other categories under the 'participation and Action' dimension in the Korean Science Education Standards. 'Science-related Self-concept' exhibited the largest increase, whereas the other categories displayed little increase from the 'Positive Experience about Science' dimension category.

• Tuberculosis and Respiratory Diseases
• /
• v.49 no.4
• /
• pp.421-431
• /
• 2000

Background : The length of postoperative drug therapy remains controversial in pulmonary tuberculosis. We analyzed our experiences to determine the postoperative duration of chemotherapy after resection. Method : A retrospective review was performed in 66 of 95 patients that underwent pulmonary resection for pulmonary tuberculosis between January 1993 and December 1998. We compared the relapse rates according to the length of postoperative chemotherapy in each group, classified by the results of sputum AFB culture before the surgery, the number of resistant drugs, the number of prior treatment and the division of anti-TB drugs used postoperatively. Results : Fifty three of 66(80.3%) were men and 13(19.7%) were women with a median age of 33.5 years(range, 16 to 63). The mean lengths of the pre- and post-operative chemotherapies were 4.9 months, and 12.9 months respectively. Five of 66 patients (7.6%) relapsed during the mean period of follow up (39.7 months). In the group less than three times of the prior treatment, there were two relapses (20%) in Ed-the highlight above-rephrase 10 patients that were medicated for 6 months or less, and one relapse in 43 patients (2.3%) that took medicine for more than 6 months (p=0.03). In the group using second-line drugs postoperatively, there was one relapse (25%) in four patients that were medicated for 12 months or less. No patient in a total of 17 that received medicine for more than 12 months relapsed (p=0.03). Conclusion : We recommend that patients with the prior treatment less than three times should be treated for more than 6 months after resection and patients using the second-line drugs postoperatively should be medicated for more than 12 months.

• Journal of Mushroom
• /
• v.12 no.4
• /
• pp.357-362
• /
• 2014

Pathogenicity of Steinernema carpocapsae GSN1 strain was evaluated against Morophagoides moriutii larvae. In Petridish tests, insect mortality by the nematode was dose dependent, which increased with dose from 5 to 160 infective juveniles(IJs)/larva. Pathogenicity against fourth-instar larvae was higher than the rate of corresponding second- and third-instar larvae, showing 100% insect mortality with the dose of 40 IJs/$4^{th}$ instar larva and 80 IJs/$2^{nd}$ or $3^{rd}$ instar larvae. Lethal concentration values at 50% ($LC_{50}$) of S. carpocapsae GSN1 strain were 4.2 IJs/$2^{nd}$ instar larva; 8.5 IJs/$3^{rd}$ instar larva; and 2.3 IJs/$4^{th}$ instar larva, respectively. The number of nematodes established in M. moriutii larvae after infection increased in the increment of dose and insect developmental stage. The highest number of nematodes was harvested from fourth instar larvae of M. moriutii at a dose of 160 IJs per larva, showing 22.5 nematodes per insect larva. Nematode reproductive capacity was related to insect developmental stage, showing 6,335 IJs/$2^{nd}$ instar larva, 21,660 IJs/$3^{rd}$ instar larvae, and 88,700 IJs/$4^{th}$ instar larvae.

• Journal of the Korean Society of Radiology
• /
• v.17 no.3
• /
• pp.385-392
• /
• 2023

Caroli's disease is a fibrocystic liver disease. Autosomal recessive disorder is characterized by congenital multiple dilatation of the bile duct. Computerized tomography, magnetic resonance imaging, cholangiography and ultrasound are among the methods for diagnosing caroli disease. Computerized tomography is essential for detecting and distinguishing fibroplastic liver disease and is useful for determining intrahepatic bile duct dilatation. However, awareness of the possible side effects of using contrast mediums is necessary. A typical method of magnetic resonance cholangiography is used for magnetic resonance imaging. A non-invasive examination can reduce the pain of the patient, and the anatomical structure of the bile pancreatic duct and the presence or absence of lesions can be easily and quickly observed. Biliary contrast is an effective diagnostic method that can directly visualize various cystic dilatations throughout the enlarged bile duct. However, since this procedure is also an invasive procedure, it is recommended not for diagnosis but for treatment purposes. Ultrasonography can confirm similar findings to computerized tomography. The hepatic artery root is difficult to prove with conventional grayscale ultrasound. However, it is of clinical value in that it can not only describe dilated bile ducts with vascular roots in the tube but also easily identify color Doppler signals in the tube. With the development of video diagnostics, early diagnosis has become possible through computerized tomography, magnetic resonance imaging, cholangiography, and ultrasound. In order to further contribute to the development of video diagnostics so that long-term prognosis can be improved after treatment through early diagnosis, we examined what aspects of each test's caroli disease appear.

• Korean Journal of Materials Research
• /
• v.1 no.3
• /
• pp.115-124
• /
• 1991

In this study, the relationship between mechanical properties and the effects of second phase in tri-phase steel which was composed of ferrite-martensite-bainite was investigated. In order to obtain different microstructure of ferrite+martensite(DP), ferrite+bainite(F+B), and ferrite+martensite+bainite(TP, different heat treatment has been accomplished. The effects of volume fraction and microstructure of each specimen were studied on tensile property, Charpy impact energy and stretch-flangeability. As the bainite content in triphase steels increased, the tensile strength, and yield strength decreased as well as the reduction of area and strength-uniform elongation increased. However, ferrite-bainite steel had high yield ratio and yield point elongation. The Charpy impact energy of TP and F+B steel was higher than that of DP steel. In addition, the characteristics of hole expanding limit($\lambda$) of TP steel and F+B steel were higher than that of DP steel. These mechanical properties of tri-phase steel have been improved, because bainite could be deformed easily within ferrite matrix. The effect of bainite on ductility in tri-phase steel has been found to be favorable. In this experiment, tri-phase steel contained within 27% bainite volume fraction had good nechanical properties and superior stretch-flangeability.

• Journal of The Korean Association For Science Education
• /
• v.24 no.2
• /
• pp.277-286
• /
• 2004

This study investigated the types and frequencies of student-student questioning (SSQ) in a small group activities, 5 in one group or 2 in one group, during school experiments. Five girls of seventh grade were observed during school experiments and interviewed afterward. Between students, information-type questions were asked more frequently than thought-type questions. Most of the information-type questions were procedural ones and most of the thought-type questions were comprehension ones. However, thought-type questions did not make further discussion in the activities. The rate of answers in the case of 2 in one group was higher than that of 5 in one group. Moreover, the similar tendency was found when we investigated the rate of helpful question-answers. In a pair, lower achiever usually asked questions, not answered as much as in 5 in one group, and higher achiever answered. The frequency of SSQ in a pair was relatively low when there was a big difference of science achievements between pair members. In conclusion, information-type questions were asked more frequently than thought-type questions during school experiments and the rate of helpful question-answers was higher when group members was fewer.

• Journal of The Korean Association For Science Education
• /
• v.23 no.3
• /
• pp.254-264
• /
• 2003

Researches on laboratory work show that students often achieve little meaningful learning through laboratory work. One reason for this failure is that students often do not know the different types of laboratory work and the 'purposes' of them. Therefore, this study investigated middle school student' ideas about the purposes of laboratory work. To seventh grade students(n=147) of middle school in Seoul, Korea, we asked (Question 1) "Why do scientists do laboratory work?" and (Question 2) "Why do you do laboratory work in science classes?" It was required a short essay including the reasons and examples of them. From the results, it was found that 56.8% of the students had ideas that scientists do laboratory work for discovering new facts or inventing something, and 82.9% of the students responded that they do laboratory work for understanding and memorizing the contents of science textbook. In addition, the differences according to gender and to school achievement level, and the relationship between the ideas about scientists' laboratory work and about school science laboratory work were examined. The results showed that boys responded 'social usefulness' more frequently than girl, while girls mentioned 'personal pleasure' more frequently than boys in relation to the purposes of scientists' laboratory work(p<.05). According to the achievement level, it was founded that 'middle' level students replied 'to remember' more frequently than high and low levels in relation to school science laboratory work. Finally, students who had ideas that scientists do laboratory work for verifying a theory had the similar ideas about school science laboratory work. In conclusion, students are lack of diverse and proper views about laboratory work. It is recommended that teacher need to make clear the purpose of laboratory work and help students to understand of it.