• Journal of the Korean Recycled Construction Resources Institute
• /
• v.9 no.2
• /
• pp.152-160
• /
• 2021

Converter steel slag(BOF slag) is a vast amount of solid waste generated in the steelmaking process which has very low utilization rate in Korea. Due to the presence of free CaO which can derive bad volume stability in BOF slag, it usually land filled. For recycling BOF and identify its applicability as fine aggregate, this study investigates the fundamental characteristics of mortar with cement replaced ferronickel slag(FNS), which has the potential to be used as a binder. The results suggest that the mineral phases of BOF slag mainly include larnite(CaSiO₄), mayenite(Ca₁₂Al₁₄O₃₃) and wuestite(FeO) while olivine crystallines are shown in FNS. The results of flow and setting time reveals that the flowability and process of hardening increased when the amount of FNS and BOF slag incorporated was increased. The length change shows that the amount of change in the length of the mortar was almost constant regardless of mix proportion while compressive strength was reduced. Micro structure test results revealed that FNS or/and BOF slag mix took a long time to react in the cement matrix to form a complete hydration products. To achieve the efficient utilization of B OF slag as construction materials, proper replacement rate is necessary.

• Microbiology and Biotechnology Letters
• /
• v.47 no.3
• /
• pp.343-349
• /
• 2019

Gul jeotgals (GJs) were prepared using solar salt aged for 3 years. One sample was fermented using starters, such as Bacillus subtilis JS2 and Tetragenococcus halophilus BS2-36 (each $10^6CFU/g$), and another sample was fermented without starters for 49 days at $10^{\circ}C$. Initial counts of bacilli and lactic acid bacteria (LAB) in non-starter GJ were found to be $3.20{\times}10^2$ and $7.67{\times}10^1CFU/g$ on day 0, and increased to $1.37{\times}10^3$ and $1.64{\times}10^6CFU/g$ on day 49. Those of starter GJ were found to be $2.10{\times}10^5$ and $3.30{\times}10^7CFU/g$ on day 49, indicating the growth of starters. The pH values of GJ were $5.93{\pm}0.01$ (non-starter) and $5.92{\pm}0.01$ (starter) on day 0 and decreased to $5.78{\pm}0.01$ (non-starter) and $5.75{\pm}0.01$ (starter) on day 49. Amino-type nitrogen (ANN) production increased continuously during fermentation, and $407.19{\pm}15.85$ (non-starter) and $398.04{\pm}13.73$ (starter) mg% on day 49. Clone libraries of 16S rRNA genes were constructed from total DNA extracted from non-starter GJ on days 7, 21, and 42. Nucleotide sequences of Escherichia coli transformants harboring recombinant pGEM-T easy plasmid containing 16S rRNA gene inserts from different bacterial species were analyzed using BLAST. Uncultured bacterium was the most dominant group and Gram - bacteria such as Acidovorax sp., Afipia sp., and Variovorax sp. were the second dominant group. Bacillus amyloliquefaciens (day 7), Bacillus velezensis (day 21 and 42), and Bacillus subtilis (day 42) were observed, but no lactic acid bacteria were detected. Acidovorax and Variovorax species might play some role in GJ fermentation. Further studies on these bacteria are necessary.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.21 no.2
• /
• pp.227-242
• /
• 2019

This paper presents a method to predict ground types ahead of a tunnel face utilizing operational data of the earth pressure-balanced (EPB) shield tunnel boring machine (TBM) when running through soil ground. The time series analysis model which was applicable to predict the mixed ground composed of soils and rocks was modified to be applicable to soil tunnels. Using the modified model, the feasibility on the choice of the soil conditioning materials dependent upon soil types was studied. To do this, a self-organizing map (SOM) clustering was performed. Firstly, it was confirmed that the ground types should be classified based on the percentage of 35% passing through the #200 sieve. Then, the possibility of predicting the ground types by employing the modified model, in which the TBM operational data were analyzed, was studied. The efficacy of the modified model is demonstrated by its 98% accuracy in predicting ground types ten rings ahead of the tunnel face. Especially, the average prediction accuracy was approximately 93% in areas where ground type variations occur.

• Animal Bioscience
• /
• v.34 no.1
• /
• pp.74-84
• /
• 2021

Objective: Feed additives that modify rumen fermentation can be used to prevent metabolic disturbances such as acidosis and optimize beef cattle production. The study evaluated the effects of liquid and powdered forms of polyclonal antibody preparation (PAP) against Streptococcus bovis and Fusobacterium necrophorum on rumen fermentation parameters in ruminally cannulated non-lactating dairy cows that were adapted or unadapted to a high concentrate diet. Methods: A double 3×3 Latin square design was used with three PAP treatments (control, powdered, and liquid PAP) and two adaptation protocols (adapted, unadapted; applied to the square). Adapted animals were transitioned for 2 weeks from an all-forage to an 80% concentrate diet, while unadapted animals were switched abruptly. Results: Interactions between sampling time and adaptation were observed; 12 h after feeding, the adapted group had lower ruminal pH and greater total short chain fatty acid concentrations than the unadapted group, while the opposite was observed after 24 h. Acetate:propionate ratio, molar proportion of butyrate and ammonia nitrogen concentration were generally greater in adapted than unadapted cattle up to 36 h after feeding. Adaptation promoted 3.5 times the number of Entodinium protozoa but copy numbers of Streptococcus bovis and Fibrobacter succinogens genes in rumen fluid were not affected. However, neither liquid nor powdered forms of PAP altered rumen acidosis variables in adapted or unadapted animals. Conclusion: Adaptation of cattle to highly fermentable carbohydrate diets promoted a more stable ruminal environment, but PAP was not effective in this study in which no animal experienced acute or sub-acute rumen acidosis.

• Korean journal of applied entomology
• /
• v.59 no.4
• /
• pp.421-425
• /
• 2020

We investigated an ecologically-sensitive method to control Polyphagotarsonemus latus in a green perilla polyvinyl house using concentrated pyrethrum. The survival rates of Polyphagotarsonemus latus nymphs and adults to 2%, 4%, and 6% pyrethrum 3 days after spraying were 58.1%, 27.5%, and 22.7% respectively, and 73.4%, 37.3%, and 30.6% at 5 days after spraying. These results show that the most effective control occurred using 6% pyrethrum. To investigating the densities of P. latus on a 1 cm diameter leaf-disk of green perilla, we sprayed the leaf every 10 days from May 10 with 6% pyrethrum 1,000 times and milbemectin EC 2% 1,000 times. The period chosen was one where the incidence of P. latus could be predicted. The density was kept low during the treatment period. However, if leaf damage had already occurred from P. latus, the density could not be decreased by spraying 1 or 2 times each week where milbemectin EC 2% was used, but the population could be reduced when sprayed 3 times. Therefore, in order to effectively control P. latus in green perilla greenhouses, it is important to begin treatment at an early stage when P. latus are first observed.

• Journal of Neurogastroenterology and Motility
• /
• v.25 no.3
• /
• pp.343-362
• /
• 2019

Background/Aims There has been major progress in our understanding of the irritable bowel syndrome (IBS), and novel treatment classes have emerged. The Rome IV guidelines were published in 2016 and together with the growing body of Asian data on IBS, we felt it is timely to update the Asian IBS Consensus. Methods Key opinion leaders from Asian countries were organized into 4 teams to review 4 themes: symptoms and epidemiology, pathophysiology, diagnosis and investigations, and lifestyle modifications and treatments. The consensus development process was carried out by using a modified Delphi method. Results Thirty-seven statements were developed. Asian data substantiate the current global viewpoint that IBS is a disorder of gut-brain interaction. Socio-cultural and environmental factors in Asia appear to influence the greater overlap between IBS and upper gastrointestinal symptoms. New classes of treatments comprising low fermentable oligo-, di-, monosacharides, and polyols diet, probiotics, non-absorbable antibiotics, and secretagogues have good evidence base for their efficacy. Conclusions Our consensus is that all patients with functional gastrointestinal disorders should be evaluated comprehensively with a view to holistic management. Physicians should be encouraged to take a positive attitude to the treatment outcomes for IBS patients.

• Korean Journal of Remote Sensing
• /
• v.36 no.6_2
• /
• pp.1605-1613
• /
• 2020

The tidal channel is a coastal sedimentary terrain that plays the most important role in the formation and development of tidal flats, and is considered a very important index for understanding and distribution of tidal flat sedimentation/erosion terrain. The purpose of this study is to understand the changes in tidal channels by a period after the opening of the floodgate of the seawall in the reclaimed land of Sihwa Lake using KOMPSAT high-resolution multispectral satellite image data and to evaluate the applicability and efficiency of high-resolution satellite images. KOMPSAT 2 and 3 images were used for extraction of the tidal channels' lineaments in 2009, 2014, and 2019 and were applied to supervised classification method based on Principal Component Analysis (PCA), Artificial Neural Net (ANN), Matched Filtering (MF), and Spectral Angle Mapper (SAM) and band ratio techniques using Normalized Difference Water Index (NDWI) and MF/SAM. For verification, a numerical map of the National Geographic Information Service and Landsat 7 ETM+ image data were utilized. As a result, KOMPSAT data showed great agreement with the verification data compared to the Landsat 7 images for detecting a direction and distribution pattern of the tidal channels. However, it has been confirmed that there will be limitations in identifying the distribution of tidal channels' density and providing meaningful information related to the development of the sedimentary process. This research is expected to present the possibility of utilizing KOMPSAT image-based high-resolution remote exploration as a way of responding to domestic intertidal environmental issues, and to be used as basic research for providing multi-platform-image-based convergent thematic maps and topics.

• Journal of The Korean Association of Information Education
• /
• v.24 no.5
• /
• pp.511-518
• /
• 2020

Preparing for the Fourth Industrial Revolution and Corona-19, our education is expanding a new chapter of learning to the era of AI education that incorporates software technology beyond software education. In this study, we will analyze the case of learner-centered assessment in software education and examine the assessment direction of artificial intelligence education through its effectiveness. Through the case of applying learner-centered assessment to non-computer subjects including computer subjects, we sought the effects on learners' learning, environmental conditions and assessment models of learner-centered evaluation, and through the case of applying the learner-centered assessment model to software education, we wanted to find out what the learner-centered assessment in artificial intelligence education suggests to the educational site. According to the analysis, the learner-centered assessment had a significant effect on the learner's achievement goal, and it is expected that the learner-centered assessment in artificial intelligence education will be carried out smoothly when an objective evaluation system and objective evaluation model are designed to help the learner's assessment, building digital environment conditions based on intelligent information technology.

• Korean journal of applied entomology
• /
• v.59 no.4
• /
• pp.303-309
• /
• 2020

The populations of Polyphagostarsonemus latus (Acari: Tarsonemidae) have been causing serious economic damages to farmers by directly feeding on leaves of green perilla. However, sampling of P. latus is impossible because there is no suitable sample unit until now. Thus, this study was conducted to suggest suitable sample unit and required sample number for P. latus on green perilla. Individuals of P. latus started to occurr from the leafstalk within a leaf. They required approximated 25 days to spread to all areas within a leaf. New shoots would be a suitable sample unit for P. latus on green perilla because its density on shoots per ㎠ was always higher than the densities on fully grown and moderately grown leaves. Required sample number at D = 0.25 was estimated as a shoot when eggs, nymphs, and adults of P. latus were observed within a leaf. Therefore, Using this small sample unit for sampling of P. latus on green perilla could be economical and efficient.

• Journal of The Korean Association of Information Education
• /
• v.25 no.2
• /
• pp.227-237
• /
• 2021

In this thesis, a survey was conducted on elementary school teachers about the establishment of information subjects in elementary schools. As a result, the opinion that information subjects should be newly established for ICT literacy education and SW/AI education in elementary schools was very high. In addition, if it is difficult to establish a new information subject, opinions in favor of the organization of the information subject as an autonomous subject using the discretionary time of the principal were high. In light of the results of this analysis, it is judged that it is necessary to establish a new information subject for ICT literacy education and SW/AI education in the next elementary school curriculum. However, if it is difficult to establish a new information course, it is necessary to come up with a plan that can be operated in the form of autonomous subject for students wishing to learn SW/AI. And it is judged that the number of class hours should be secured for at least 1 hour or 2 hours per week in the 3rd grade and above.