• Economic and Environmental Geology
• /
• v.50 no.4
• /
• pp.257-266
• /
• 2017

Batch experiments were performed to develop the method for the pH reduction of recycled aggregate by using $scCO_2$ (supercritical $CO_2$), maintaining the pH of extraction water below 9.8. Three different aggregate types from a domestic company were used for the $scCO_2$-water-recycled aggregate reaction to investigate the low pH maintenance of aggregate during the reaction. Thirty five gram of recycled aggregate sample was mixed with 70 mL of distilled water in a Teflon beaker, which was fixed in a high pressurized stainless steel cell (150 mL of capacity). The inside of the cell was pressurized to 100 bar and each cell was located in an oven at $50^{\circ}C$ for 50 days and the pH and ion concentrations of water in the cell were measured at a different reaction time interval. The XRD and SEM-EDS analyses for the aggregate before and after the reaction were performed to identify the mineralogical change during the reaction. The extraction experiment for the aggregate was also conducted to investigate the pH change of extracted water by the $scCO_2$ treatment. The pH of the recycled aggregate without the $scCO_2$ treatment maintained over 12, but its pH dramatically decreased to below 7 after 1 hour reaction and maintained below 8 for 50 day reaction. Concentration of $Ca^{2+}$, $Si^{4+}$, $Mg^{2+}$ and $Na^+$ increased in water due to the $scCO_2$-water-recycled aggregate reaction and lots of secondary precipitates such as calcite, amorphous silicate, and hydroxide minerals were found by XRD and SEM-EDS analyses. The pH of extracted water from the recycled aggregates without the $scCO_2$ treatment maintained over 12, but the pH of extracted water with the $scCO_2$ treatment kept below 9 of pH for both of 50 day and 1 day treatment, suggesting that the recycled aggregate with the $scCO_2$ treatment can be reused in real construction sites.

• Economic and Environmental Geology
• /
• v.51 no.4
• /
• pp.359-370
• /
• 2018

The batch and column experiments were performed to overcome the limitation of the neutralization process using the $scCO_2$-water-recycled aggregate, reducing its treatment time to 3 hour. The waste cement mortar and two kinds of recycled aggregate were used for the experiment. In the extraction batch experiment, three different types of waste mortar were reacted with water and $scCO_2$ for 1 ~ 24 hour and the pH of extracted solution from the treated waste mortar was measured to determine the minimum reaction time maintaining below 9.8 of pH. The continuous column experiment was also performed to identify the pH reduction effect of the neutralization process for the massive recycled aggregate, considering the non-equilibrium reaction in the field. Thirty five gram of waste mortar was mixed with 70 mL of distilled water in a high pressurized stainless steel cell at 100 bar and $50^{\circ}C$ for 1 ~ 24 hour as the neutralization process. The dried waste mortar was mixed with water at 150 rpm for 10 min. and the pH of water was measured for 15 days. The XRD and TG/DTA analyses for the waste mortar before and after the reaction were performed to identify the mineralogical change during the neutralization process. The acryl column (16 cm in diameter, 1 m in length) was packed with 3 hour treated (or untreated) recycled aggregate and 220 liter of distilled water was flushed down into the column. The pH and $Ca^{2+}$ concentration of the effluent from the column were measured at the certain time interval. The pH of extracted water from 3 hour treated waste mortar (10 ~ 13 mm in diameter) maintained below 9.8 (the legal limit). From XRD and TG/DTA analyses, the amount of portlandite in the waste mortar decreased after the neutralization process but the calcite was created as the secondary mineral. From the column experiment, the pH of the effluent from the column packed with 3 hour treated recycled aggregate kept below 9.8 regardless of their sizes, identifying that the recycled aggregate with 3 hour $scCO_2$ treatment can be reused in real construction sites.

• Korean Journal of Ecology and Environment
• /
• v.41 no.2
• /
• pp.144-154
• /
• 2008

The purpose of this study was to describe quantitatively trophic structures and to analyze energy flows in the Lake Namyang using the Ecopath with ecosim (Walter et al., 1997). The sampling and analyses were carried out at 6 sampling sites of the Lake Namyang during May and November in 2007. A total of 10 groups were considered in this study (detritus, macrophytes, phytoplankton, zooplankton, zoobenthos, Cyprinus carpio, Carassius cuvieri, Carassius auratus, Pseudobagrus fulvidraco and other fishes) to assess the trophic relationship, energy flows and interactions between them. As a result, it was concluded that Lake Namyang was consisted of primary producers (Detritus, Macrophytes, Phytoplankton), primary consumers (Zooplankton, Zoobenthos, Cyprinus carpio, Carassius cuvieri, Carassius auratus, Other fishes) and secondary consumer (Pseudobagrus fulvidraco). The total system throughput was estimated at $14.1\;kg\;m^{-1}\;year^{-1}$ including a consumption of 39%, exports of 21%, respiratory flows of 12% and flows into detritus of 28%. MTI analyses indicate that Pseudobagrus fulvidraco have positive impact on Cyprinus carpio, Carassius cuvieri and Carassius auratus. On the other hand, other fishes have negative impact on Cyprinus carpio, Carassius cuvieri and Carassius auratus. All the functional groups except detritus had a negative impact on themselves and this may show within-group competition for the same resources.

• Food Science and Preservation
• /
• v.22 no.6
• /
• pp.920-925
• /
• 2015

The microbial composition in Nuruk, a Korean cereal fermentation starter, is a critical factor for the quality and organoleptic properties of traditional alcoholic beverages. This study was aimed at monitoring the compositional change and enzyme activity of culturable lactic acid bacteria (LAB) in two types of Nuruk fermented at different temperatures. All culturable LAB were isolated at various time points (0, 3, 6, 10, 20, and 30 days) and identified by 16S rRNA sequencing. In traditional Nuruk type A (TN-A), which was fermented at $36^{\circ}C$, the population of total culturable LAB during the fermentation period was between $10^4$ and $10^5$ log CFU/mL. On the other hand, the LAB population in traditional Nuruk type B (TN-B) fermented at $45^{\circ}C$ (primary fermentation for 10 days) and $35^{\circ}C$ (secondary fermentation for 20 days) was $10^2$ log CFU/mL; however, these bacteria could not be detected after 6 days. Major LAB strains were identified in both Nuruk types: (1) from the MRS-culture of TN-A, Pediococcus pentosaceus at 3-30 days; (2) from MRS-culture of TN-B, P. pentosaceus at 3 days and Enterococcus hirae at 6 days. The protease activities of the dominant LAB isolated from the TN-A and TN-B cultures were within the ranges of 0.64~1.03 mg/mL and 0.74~0.81 mg/mL (tyrosine content), respectively, whereas the ${\alpha}$-amylase activities were 0.75~0.98 mg/mL and 0.78~0.79 mg/mL (amylose content), respectively.

• Journal of the Society of Disaster Information
• /
• v.11 no.4
• /
• pp.556-569
• /
• 2015

With about 75% of the population of Korea criticizing the government's disaster policy and a failure to respond to large-scale emergency like the Sewol ferry sinking means that there is a deep distrust in the government. In order to prevent dreadful disasters such as the Sewol ferry sinking, it is important to secure a prime time with respect to disaster safety. Improving crisis management skills and managerial role of police officers who are in close proximity to the people is necessary for the success of disaster management. With disaster management as one of the most essential missions of the police, as a part of a national crisis management, a step by step strengthening of the disaster safety management system of the police is necessary, as below. First, at the prevention phase, law enforcement officers were not injected into for profit large-scale assemblies or events, but in the future the involvement, injection should be based on the level of potential risk, rather than profitability. In the past and now, the priortiy was the priority was on traffic flow, traffic communication, however, the paradigm of traffic policy should be changed to a safety-centered policy. To prevent large-scale accidents, police investigators should root out improper routines and illegal construction subcontracting. The police (intelligence) should strengthen efforts to collect intelligence under the subject of "safety". Second, with respect to the preparatory phase, on a survey of police officers, the result showed that 72% of police officers responded that safety management was not related to the job descriptions of the police. This, along with other results, shows that the awareness of disaster safety must be adopted by, or rather changed in the police urgently. The training in disaster safety education should be strengthened. A network of experts (private, administrative, and police) in safety management should be established to take advantage of private resources with regard to crisis situtions. Third, with respect to the response phase, for rapid first responses to occur, a unified communication network should be established, and a real-time video information network should be adopted by the police and installed in the police situation room. Fourth, during the recovery phase, recovery teams should be injected, added and operated to minimize secondary damage.

• Journal of Chest Surgery
• /
• v.52 no.4
• /
• pp.248-329
• /
• 2019

Background: Though clinical practice guidelines (CPGs) for cardiac rehabilitation (CR) are an effective and widely used treatment method worldwide, they are as yet not widely accepted in Korea. Given that cardiovascular disease is the second leading cause of death in Korea, it is urgent that CR programs be developed. In 2008, the Government of Korea implemented CR programs at 11 university hospitals as part of its Regional Cardio-Cerebrovascular Center Project, and 3 additional medical facilities will be added in 2019. In addition, owing to the promotion of CR nationwide and the introduction of CR insurance benefits, 40 medical institutions nationwide have begun CR programs even as a growing number of medical institutions are preparing to offer CR. The purpose of this research was to develop evidence-based CPGs to support CR implementation in Korea. Methods: This study is based on an analysis of CPGs elsewhere in the world, an extensive literature search, a systematic analysis of multiple randomized control trials, and a CPG management, development, and assessment committee comprised of 33 authors-primarily rehabilitation specialists, cardiologists, and thoracic surgeons in 21 university hospitals and 2 general hospitals. Twelve consultants, primarily rehabilitation, sports medicine, and preventive medicine specialists, CPG experts, nurses, physical therapists, clinical nutritionists, and library and information experts participated in the research and development of these CPGs. After the draft guidelines were developed, 3 rounds of public hearings were held with staff members from relevant academic societies and stakeholders, after which the guidelines were further reviewed and modified. Results: CR involves a more cost-effective use of healthcare resources relative to that of general treatments, and the exercise component of CR lowers cardiovascular mortality and readmission rates, regardless of the type of coronary heart disease and type and setting of CR. Conclusion: Individualized CR programs should be considered together with various factors, including differences in heart function and lifestyle, and doing so will boost participation and adherence with the CR program, ultimately meeting the final goals of the program, namely reducing the recurrence of myocardial infarction and mortality rates.

• The Journal of the Petrological Society of Korea
• /
• v.28 no.3
• /
• pp.157-169
• /
• 2019

Pseudotachylytes, produced by frictional heating during seismic slip, provide information that is critical to understanding the physics of earthquakes. We report the results of occurrence, structural characteristics, scanning electron microscopic observation and geochemical analysis of pseudotachylytes, which is presumed to have formed after the Late Cretaceous in outcrops of the Paleoproterozoic granitic gneiss on the Bulil waterfall of the Jirisan area, Yeongnam massif, Korea. Fault rocks, which are the products of brittle deformation under the same shear stress regime in the study area, are classified as pseudotachylyte and foliated cataclasite. The occurrences of pseudotachylyte identified on the basis of thickness and morphology are fault vein-type and injection vein-type pseudotachylyte. A number of fault vein-type pseudotachylytes occur as thin (as thick as 2 cm) layers generated on the fault plane, and are cutting general foliation and sheared foliation developed in granitic gneiss. Smaller injection vein-type pseudotachylytes are found along the fault vein-type pseudotachylytes, and appear in a variety of shapes based on field occurrence and vein geometry. At a first glance fault vein-type seudotachylyte looks like a mafic vein, but it has a chemical composition almost identical to the wall rock of granitic gneiss. Also, it has many subrounded clasts which consist predominantly of quartz, feldspar, biotite and secondary minerals including clay minerals, calcite and glassy materials. Embayed clasts, phenocryst with reaction rim, oxide droplets, amygdules, and flow structures are also observed. All of these evidences indicate the pseudotachylyte formed due to frictional melting of the wall rock minerals during fault slip related to strong seismic faulting events in the shallow depth of low temperature-low pressure. Further studies will be conducted to determine the age and mechanical aspect of the pseudotachylyte formation.

• Journal of the Economic Geographical Society of Korea
• /
• v.25 no.1
• /
• pp.109-130
• /
• 2022

The Vietnamese government has proposed contract farming through a new type of cooperative as an institutional innovation which aims to restructure the agricultural sector. However, policy changes often impact farmers, who bear the primary effects of the transition process. Understanding households' strategies for land use and livelihood is crucial for policymaking in the agricultural development field. This study was conducted in the rural Binh Dao commune in Central Vietnam. We analyzed household members' labor force changes and their livelihood behaviors after their participation in a contract farming scheme using qualitative analysis methods combined with geographic information system (GIS) support, based on secondary data and in-depth interviews of 190 farmers. Simultaneously, we created a digital map of the cooperative's production area to investigate changes in land use and production activities. The findings show that contract farming shaped the vertical coordination of the value chain from the farmers to the cooperative and agricultural product trading companies. Subsequently, it encouraged land use and labor efficiency due to mechanical support. In addition, it also increased productivity and protected farmers from market risks. However, despite its positive effects on agricultural productivity in this case, the contract farming scheme could not achieve the restructuring of the rural labor force toward non-agricultural sectors. Ironically, farmers in the Binh Dao commune tended to increase cultivable land during the agricultural restructuring program, rather than switching their labor forces to non-agricultural sectors. The lack of stable non-farming job opportunities in rural Vietnam results in challenges to the efficiency of agricultural restructuring programs. Consequently, farmers in the Binh Dao commune are still smallholder farmers, depending on the family labor force.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.50 no.1
• /
• pp.1-19
• /
• 2022

The Geumgang Pine (Pinus densiflora) Forest in Sogwang-ri, Uljin has traditionally been a pine tree protection area (prohibited forest) for timber production purposes, and is now designated and managed as a protected area for forest genetic resource conservation by the Korea Forest Service. This study, we analyzed topographical characteristics, existing vegetation, tree age, and plant community structure, and proposed a sustainable management method for the Geumgang Pine (Pinus densiflora) Forest in Sogwang-ri, Uljin for timber havesting purposes. The topographical characteristics of the target area were 36.7% ridges and 38.7% valleys; the ratio of ridges to valleys was similar, and the slopes formed 24.7% of the total area. The types of pine forest communities are divided into six types based on the progress of pine forest renewal, the competition with other species such as deciduous broadleaf trees, and the formation of layered structures. It has been confirmed that the age of the large-diameter pine trees (40~60cm in diameter) is approximately 60~70 years, which is relatively low. As a result of the analysis of the relative importance percentage and layered structure, differences depended on the progress of the pine forest renewal project, and not only the maintenance of the pine forest, but also the creation of a secondary growth forest, the density adjustment of pine trees, and the active management of competitive trees. The average basal area by the community was 12,642.1~25,424.4cm² for the tree layer and 1.8~1,956.5cm² for the low tree layer based on a quadrat of 400m². The difference in the basal area appeared to depend on the size and number of trees forming the tree layer and the degree of pine forest renewal (the degree of time elapsed after thinning pine trees). The average number of species that appeared in each community was 8.7-20.3; there were many species located in valleys, and the type competes with deciduous broadleaf trees due to the lack of management. The diversity of species ranged from 0.6915-1.0942, and was evaluated as low compared to pine communities in central temperate zones. In this paper, we determined the management goals of Geumgang Pine (Pinus densiflora) Forest in Sogwang-ri, Uljin to produce timber with high economic value, and suggested efficient vegetation management for continuous afforestation, the establishment of a timber production system, and improvement of wood production as a management direction.

• Korean Journal of Mineralogy and Petrology
• /
• v.35 no.3
• /
• pp.283-298
• /
• 2022

In this study, we investigated the mineral geochemistry of the albite-spodumene pegmatite, associated exogreisen, and wall rock from the Boam Li deposit, Wangpiri, Uljin, Gyeongsangbuk-do, South Korea. The paragenesis of the Boam Li deposit consists of two stages; the magmatic and endogreisen stages. In the magmatic stage, pegmatite dikes mainly composed of spodumene, albite, quartz, and K-feldspar intruded into the Janggun limestone formation. In the following endogreisen stage, the secondary fine-grained albite along with muscovite, apatite, beryl, CGM(columbite group mineral), microlite, and cassiterite were precipitated and partly replaced the magmatic stage minerals. Exogreisen composed of tourmaline, quartz, and muscovite develops along the contact between the pegmatite dike and wall rock. The Cs contents of beryl and muscovite and Ta/(Nb+Ta) ratio of CGM are higher in the endogreisen stage than the magmatic stage, suggesting the involvement of the more evolved melts in the greisenization than in the magmatic stage. Florine-rich and Cl-poor apatite infer that the parental magma is likely derived from metasedimentary rock (S-type granite). P₂O₅ contents of albite in the endogreisen stage are below the detection limit of EDS while those of albite in the magmatic stage are 0.28 wt.% on average. The lower P₂O₅ contents of the former albite can be attributed to apatite and microlite precipitation during the endogreisen stage. Calcium introduced from the adjacent Janggun formation may have induced apatite crystallization. The interaction between the pegmatite and Janggun limestone is consistent with the gradual increase in Ca and other divalent cations and decrease in Al from the core to the rim of tourmaline in the exogreisen.