• Proceedings of the Korean Society for Rock Mechanics Conference
• /
• 2000.09a
• /
• pp.93-103
• /
• 2000

The concrete plug in an underground cavern prevents the stored product (oil, gas, etc) from leaking and the excessive show of underground water, so it plays an important role in construction and operation of the storage cavern. Additionally, it should maintain its stability under every possible loading condition. Once the plug is constructed, the cavern is isolated from the external access. Therefore, mechanical and hydraulic consideration should be made in construction to fulfill its function. Therefore, in this study, numerical analyses were conducted to study the optimal shape and thickness of the plug with respect to the various conditions of installation depth, the shape of the plug, in-situ stress ratio (K), the condition of rock-plug interface, and the effect of Excavation Damaged Zone (EDZ). This paper also presents the effect of slot depth on the hydraulic behavior of the plug. These analyses were carried out by using the 2-dimensional finite difference code, rm FLAC, and the 3D code, m FLA $C^{3D}$./.

• Tunnel and Underground Space
• /
• v.10 no.3
• /
• pp.344-354
• /
• 2000

The concrete plug in an underground cavern prevents the stored product (oil, gas, etc) from leaking and the excessive inflow of underground water, so it plays an important role in construction and operation of the storage cavern. Additionally, it should maintain its stability under every possible loading condition. Once the plug is constructed, the cavern is isolated from the external access. Therefore, mechanical and hydraulic consideration should be made in construction to fulfill its function. Therefore, in this study, numerical analyses were conducted to study the optimal shape and thickness of the plug with respect to the various conditions of installation depth, the shape of the plug, in-situ stress ratio (K), the condition of rock-plug interface, and the effect of Excavation Damaged Zone (EDZ). This paper also presents the effect of slot depth on the hydraulic behavior of the plug. These analyses were carried out by using the 2-dimensional finite difference code, rm FLAC, and the 3D code, rm FLAC$\^$3D/.

• Food Science of Animal Resources
• /
• v.35 no.1
• /
• pp.41-49
• /
• 2015

This study was performed to assess the antioxidant activity of Allium hookeri root extract (AHE) on lipid oxidation of raw sulfur-fed pork patties for 14 d of refrigerated storage. Different concentration of ethanol (0-100%) and time (1-12 h) were applied to determine the extraction condition. Water (0% ethanol) extraction for 1 h was selected as an optimal extraction condition of AHE for the following study showing the highest total phenolic content and total flavonoid content, as well as the strongest antioxidant activity. The 1% AHE (SP1), 3% AHE (SP2), and 0.05% ascorbic acid (SP3) were added into sulfur-fed pork patties against controls; SP0 (sulfur-fed pork patties with no AHE) and P0 (normal pork patties with no AHE). The pH values of P0 and SP0 significantly increased (p<0.05) than others on 14 d and redness of P0 showed the largest decrement during storage. P0 and SP0 showed higher production of conjugated dienes on d 7 than others (p<0.05). Thiobarbituric acid reactive substances (TBARS) values were decreased in proportion to the increased level of AHE on 14 d (p<0.05) resulting in higher TBARS values on P0 and SP0 (p<0.05) and the negative correlation between AHE level and TBARS were also demonstrated (r=-0.910, p=0.001). Therefore, the results suggest that AHE effectively retarded the lipid oxidation rate of sulfur-fed pork patties indicating the potential usage of AHE as a natural preservative.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.7
• /
• pp.554-564
• /
• 2017

The purpose of this study is to assist farmers in determining the optimal time for the shipment of stored apples by investigating the market trends, storage status and release dates of low-temperature stored apples. We surveyed 300 apple cultivation farms in Daegu, Gyeongbuk Province, which is the main producer of apples, and examined the cultivars, cultivation areas, storage conditions, and shipment status of apples. The main results are as follows: the proportion of apples cultivatedat different ripening times was surveyed. According to the results, the proportions of early, middle and late varieties were 78.3%, 63.7% and 96.0%, respectively. Also, 48.7% of the farm households surveyed had cold storage facilities. The average storage cost per apple box(15kg) was 978.3 won for self-storage and 1,771.8 won for consignment storage. For the six(6) months between November and April, the proportion of shipped apples was 91.6% of the total stored apples. The (average total?)annual apple shipment, including apples stored in general storage warehouses, was 744.4 boxes. The (average total?) annual shipment of cold storage apples was 616 boxes. The stored apples were mainly shipped to 'wholesale markets', which have the highest sales share, followed by 'production site collectors' and then 'supermarkets'. The most common shipping method of the apples was by general trucks, followed by low-temperature trucks, and finally by delivery services. The analysis of the factors influencing the decision to release apples by period showed that it was affected by the storage cost, loss rate, and customary shipping in the off-season(from May to August). On the other hand, in the general release season(from November to April), the statistically significant decision factors for the release of apples were the future expected price, storage cost and decision of the leading farmer groups. For farmers with a high share of general shipment, the deciding factors for the release of apples were the future expected price, storage cost, high income expectation, and decision by leading farmers.

• KSBB Journal
• /
• v.27 no.1
• /
• pp.21-27
• /
• 2012

Five yeast strains were isolated from traditional Makgeollies, Makgeollies were made by isolated yeasts after cultivation, and then property changes of Makgeollies were analyzed according to yeasts, storage temperatures and storage periods. Average pHs were shown to be 3.22~3.88 and statistically changed according to yeasts used, storage temperatures and storage periods. Total acidities were statistically changed according to storage periods. Amino-type nitrogen contents were in the ranges of 0.009~0.245% and statistically changed according to storage temperatures especially at 18 and $25^{\circ}C$ for 15 days. Average alcohol concentrations were in the ranges of 7.5~18.5% and reduced until 10 days and increased for 15 days according to yeasts used and storage periods. Consequently, Makgeollies, made by isolated yeast strains originated from traditional Makgeollies, revealed that alcohol concentrations and amino-type nitrogen contents were changed but pHs and total acidities were not dramatically changed according to yeasts used. It suggests that development of various Makgeollies would be possible using isolated yeast strains in this study, and optimal storage condition of ready-made Makgeollies to maintain its original property turned out to be at $4^{\circ}C$ for 5 days. Especially, Makgeolli made by F strain showed the best quality on its property, therefore Makgeolli which maintains its property stably until 10 days when stored at $4^{\circ}C$ could be made using this strain.

• The Journal of the Korea Contents Association
• /
• v.22 no.1
• /
• pp.646-655
• /
• 2022

This study was conducted to investigate the quality characteristics of Kimchi during fermentation and storage according to containers with native plant extract. The containers used in the experiment were antimicrobial polypropylene containers(KAPP) developed with the addition of native plant extracts, and it was tested by comparing the microbial changes and sensory characteristics of the existing commercial containers, such as polypropylene containers(KPP), stainless steel containers(KST), and porcelain containers(KPC). Change in total microbial cell were similar for each container. Coliform maintained the lowest level from 15 days after storage to 50 days. Leuconostoc spp. and Lactobacillus spp. showed a rapid increase in all four storage containers until the 15th day of storage and then decreased. The KAPP container maintained its highest level. The sensory evaluation was carried out on Kimchi optimal condition(storage 40 days). The sensory scores of KAPP were generally higher than those of other experimental samples in characteristics of appearance, odor, taste and overall preference. As a result, KAPP container has an excellent antibacterial effect as compared with the three commercially available storage containers, is effective for fermentation of lactic acid.

• International Journal of Advanced Culture Technology
• /
• v.8 no.3
• /
• pp.211-215
• /
• 2020

Currently, most of the chlorine dioxide gas is processed at the beginning of storage or distribution. It has the disadvantage of not being able to continuously process gas since there is no system that can continuously process it during the distribution process. Therefore, in order to minimize changes in freshness and quality during the distribution process of agrifood, there is a need for a sustained-release chlorine dioxide gas treatment technology that can be continuously released. Therefore, in this study, the film to be used was examined so that the chlorine dioxide gas can be continuously released for a certain period of time, the concentration of the reactant and the viscosity at the time of the reaction were determined, and a chlorine dioxide gas gel pack was manufactured using this optimal condition. In addition, the gel pack was used to measure the amount of chlorine dioxide gas released and the sterilization effect of food poisoning bacteria.

• Journal of Advanced Marine Engineering and Technology
• /
• v.33 no.7
• /
• pp.981-986
• /
• 2009

The application of a cryogenic storage system is growing fast in different kinds of fields including to keep umbilical cord blood. Umbilical cord blood stem plays an important role in the treatment of a blood and immune system related genetic diseases, cancers and blood disorders. This study gives the optimal cryogenic system for cord blood banking. Three-dimensional models are employed and finite element method is used to do structure analyses of all designed models. The results shows model 3 have a good structure properties, and model 4 shows the best structure property as its maximum is 92.9 MPa. The other is too dangerous or infeasible to support load condition that allowed by STS 304. The results can be used in the design of these kinds of systems to obtain good predictions of trends over a wide range of design alternatives and operating conditions.

• Journal of the Korean Society for Precision Engineering
• /
• v.23 no.4 s.181
• /
• pp.162-167
• /
• 2006

Hot embossing lithography(HEL) has the production advantage of comparatively few process step, simple operation, a relatively low cost for embossing tools(Si), and high replication accuracy for small features. In this paper, we considered the nano-molding characteristic according to molding parameters(temperature, pressure, times, etc) and induced a optimal molding condition using HEL. High precision nano-patter master with various shapes were designed and manufactured using the DRIE(Deep Reactive ion Etching), LPCVD(Low Pressure Chemical Vapor Deposition) and thermal oxidation process, and we investigated the molding characteristic of DVD and Blu-ray nickel stamp. We induced flow behaviors of polymer, rheology by shapes and sizes of the pattern through various molding experiments. Finally, with achieving nano-structure molding with high aspect ratio, we will secure a basic technology about the molding of large-area nano-pattern media.

• Journal of applied mathematics & informatics
• /
• v.42 no.2
• /
• pp.379-390
• /
• 2024

This study proposes a fuzzy inventory model for managing large-scale production, incorporating cost considerations. The model accounts for two types of expenditure scenarios-parametric and exponential. Uncertainty surrounds holding costs, setup costs, and demand rates. The approach considers a supply chain system with a complex manufacturing process, factoring in transportation costs based on the quantity of goods and distance between the supplier and retailer. The initial crisp model is then transformed into a fuzzy simulation, incorporating specific fuzzy variables affecting inventory costs. The proposed method significantly reduces overall inventory costs for the entire supply chain. Retailer demand is linked to inventory levels, and vendor/distributor storage deteriorates over time. The fuzzy condition assumes hexagonal variables for all associated factors. The study employs the signed distance method for defuzzification to determine the optimal order quantity with hexagonal fuzzy numbers. Mathematical examples are provided to illustrate the practicality of the proposed approach.