• Journal of Bio-Environment Control
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• v.29 no.3
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• pp.293-305
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• 2020

This experiment was aimed to identify concentrations of mineral nutrients in leaf lettuce (Lactuca sativa) grown on hydroball aquaponics and in the water for growing fish by conducting two experiments. The experiment I (Expt. I) was conducted with 12 fishes (F12) with and without filter, hydroball and plants (H12 (12 fishes, hydroball), FHP12 (12 fishes, filter, hydroball, 6 plants) and HP12 (12 fishes, hydroball, 6 plants)), and the experiment II (Expt. II) was with and without plants (FH15 (15 fishes, filter, hydroball), FHP15 (15 fishes, filter, hydroball, 6 plants)). The pH level in the water of all the treatments was decreased during the growing period, and the pH and EC of the water were lower in all the treatment with plants than those without plants in both Expt. I and Expt. II. When compared with adequate nutrient concentrations for hydroponics, nitrate nitrogen (NO₃-N) and phosphorus (P) concentrations in the fish growing water were higher under the FHP15 treatment in Expt. II; however, potassium (K), calcium (Ca), and magnesium (Mg) were only 16, 49, and 82% of hydroponics, representatively, and iron (Fe) was not detected. The fresh weight of lettuce harvested from the FHP15 treatment was 38 g, only a 30% of marketable lettuce yield. The T-N and P contents of the leaf tissue grown under the FHP15 treatment were close to the optimal level; however, the K, Ca, and iron (Fe) contents were less than the optimal with no deficiency symptom.

• Elastomers and Composites
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• v.48 no.2
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• pp.148-155
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• 2013

The crosslinking density of polymer can be quantitatively calculated by the Flory-Rehner equation using the swelling experimental data and the lattice constant ${\beta}_1$ of interaction parameter (${\chi}$) in this equation should be chosen have used cautiously. This ${\beta}_1$ is the experimental data by rule of thumb, and researchers have used little different values respectively. Generally, the average molecular weight between crosslink points $M_c$ in the Flory-Rehner equation and the Mooney-Rivlin equation have the same value, and ${\beta}_1$ can be calculated when the $M_c$ in the Flory-Rehner equation is given. Therefore, in this research, firstly we calculated the $M_c$ using the selected ${\beta}_1$ (=0.34) and the swelling experimental data of 1,2,3-triazole polymer from the Flory-Rehner equation, secondly the $M_c$ from the Mooney-Rivlin equation is calculated by the tensile experimental data, and finally two $M_c$ were compared. As a result, two $M_c$ values were almost the same, and it was proved that the ${\beta}_1$ (=0.34) was selected properly.

• Journal of the Korean Chemical Society
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• v.38 no.9
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• pp.640-652
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• 1994

This work is undertaken to determine alcohol homologues so-called fusel oil that may be present in the Korean folk sojues (distilled liquor) made from grains and to describe sample preparation and analytical method by GC-FID-MS. Solid phase extraction method for sample preparation by using porous styrene divinyl benzene polymer (Porapak Q) was compared with steam distillation and solvent extraction method. Retention behaviors of homologous series of alcohols were also studied. Log values of retention time, molecular weight, boiling point, and capacity factor of alcohols showed linear correlations to the carbon number of an alcohol, to the oven temperature, and to the dielectric constant. Components such as methyl alcohol, n-propyl alcohol, isobutyl alcohol, isopentyl alcohol, and phenethyl alcohol have been identified. The more amount of isopentyl alcohol than other alcohols are contained in the Korean folk sojues, while that of n-propyl alcohol are contained in Chinese kaoliangchiew. Degree of similarity or dissimilarity and classification of the individual samples were discussed using multivariate statistical analysis(principal components analysis) based on GC data.

• Progress in Medical Physics
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• v.26 no.2
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• pp.106-111
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• 2015

In Tomotherapy the couch sags during the treatment due to the weight of the patient. In this study, we developed a simple method to obtain the amount of the sag and the pitch angle of the couch using the image processing technique of MVCT images in Tomotherapy. Using the method we evaluated the sag and pitch of couch for 22 head and neck patients and one craniospinal irradiation (CSI) patient. The sag and the average pitch angle of couch were 0.40~1.54 mm and $0.7^{\circ}$ for head and neck patients, respectively. For head and neck patients, the sag increased as the longitudinal length of the irradiation volume increased and the pitch angle showed no relationship with the longitudinal length. For the CSI patient the sag was 4.97 mm. Using the method the amount of the couch sag could be measured easily and the measured data could be useful in determination of margins considering the table sag error.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.469-474
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• 2002

In recent years, modularization of engine parts has increased the application of plastic products in air intake systems. Plastic intake manifolds provide many advantages including reduced weight, contracted cost, and lower intake air temperatures. These manifolds, however, have some weakness when compared with customary aluminium intake manifolds, in that they have low sound transmission loss because of their lower material density. This low transmission loss of plastic intake manifolds causes several problems related to flow noise, especially when the throttle is opened quickly. The physical processes, responsible for this flow noise, include turbulent fluid motion and relative motion of the throttle to the airflow. The former is generated by high-speed airflow in the splits between the throttle valve and the inner-surface of the throttle body and surge-tank, which can be categorized into the quadrupole source. The latter induces the unsteady force on the flow, which can be classified into the dipole source. In this paper, the mechanism of noise generation from the turbulence is only investigated as a preliminary study. Stochastic noise source synthesis method is adopted for the analysis of turbulence-induced, i.e. quadrupole noise by throttle at quick opening state. The method consists of three procedures. The first step corresponds to the preliminary time-averaged Navier-Stokes computation with a $k-\varepsilon$ turbulence model providing mean flow field characteristics. The second step is the synthesis of time-dependent turbulent velocity field associated with quadrupole noise sources. The final step is devoted to the determination of acoustic source terms associated with turbulent velocity. For the first step, we used market available analysis tools such as STAR-CD, the trade names of fluid analysis tools available on the market. The steady state flows at three open angle of throttle valve, i.e. 20, 35 and 60 degree, are numerically analyzed. Then, time-dependent turbulent velocity fields are produced by using the stochastic model and the flow analysis results. Using this turbulent velocity field, the turbulence-originated noise sources, i.e. the self-noise and shear-noise sources are synthesized. Based on these numerical results, it is found that the origin of the turbulent flow and noise might be attributed to the process of formulation and the interaction of two vortex lines formed in the downstream of the throttle valve. These vortex lines are produced by the non-uniform splits between the throttle valve and inner cylinder surface. Based on the analysis, we present the low-noise design of the inner geometry of throttle body.

• Journal of the Korean Society for Railway
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• v.19 no.2
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• pp.262-269
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• 2016

Subway station scales are determined by peak predictions. In this study, the purpose behind the installation of a subway is public transportation convenience and public interest, but economic validity is also important. By proving that the scale of the station is excessive with regard to the target station size for Seoul subway Line 5-8, a reasonable plan. can be sought. According to station installation standards, the area of the station under investigation here is out of the service levels by six stages (A~F), and it must be four or more levels (D). The Actual level for the B level is a two-step design. The Actual ratio for over- Peak predictions is only 17.8% on average. The results of measurements of the excess area and determination of the excessive costs were analyzed by subdividing the area and by calculating it based on the B level, finding that it is possible to provide benefits for customers only in the current design, with an area ratio of 16.3%. Given the weight, it was estimated that current conditions can meet the needs of only 18.6% of the current area. Simplifying the scale calculation method of the station, it is convenient, safe, and advantageous to move citizens only if the scale can be streamlined. Then, with a reduced initial investment, maintenance costs during the operation can be reduced.

• Journal of the Korean GEO-environmental Society
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• v.19 no.11
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• pp.5-14
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• 2018

Worldwide, soil compaction work is one of the most important activities that are carried out on civil engineering works sites. Compaction work, particularly in the area of road construction, is considered to be important, as poor compaction work is closely related with poor construction even after a construction is complete. Currently, the plate bearing test or the sand cone method relative to the unit weight of soil test are commonly used to measure the degree of compaction, but as these require a great deal of time, equipment and manpower, it is difficult to secure economic efficiency. The method that is used to measure the degree of compaction according to the penetration depth achieved by free fall objects through gravity is the Free-Fall Penetration Test (FFPT), which uses a so-called "portable compaction measuring meter (PCMM)." In this study, the degree of compaction was measured and a penetration depth graph was developed after the field test using the portable compaction measuring meter. The coefficient of determination was 0.963 at a drop height of 10 cm, showing the highest level of accuracy. Both horizontal axis and longitudinal axis were developed in a decimal form of graph, and the range of allowable error was ${\pm}1.28mm$ based on the penetration depth. The portable compaction measuring meter makes it possible to measure the degree of compaction simply, quickly and accurately in the field, which will ensure economic efficiency and facilitate the process management.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.10
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• pp.1167-1175
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• 2016

This paper proposes an efficient page-level mapping algorithm that reduces the erase count in the FTL for flash memory systems. By maintaining the weight for each write request in the request buffer, the proposed algorithm estimates the degree of temporal locality for each incoming write request. To exploit temporal locality deliberately for determination of hot request, the degree of temporal locality should be much higher than the reference point determined experimentally. While previous LRU algorithm treats a new write request to have high temporal locality, the proposed algorithm allows write requests that are estimated to have high temporal locality to access hot blocks to store hot data intensively. The pages are more frequently updated in hot blocks than warm blocks. A hot block that has most of invalid pages is always selected as victim block at Garbage Collection, which results in delayed erase operation and in reduced erase count. Experimental results show that erase count is reduced by 9.3% for real I/O workloads, when compared to the previous LRU algorithm.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.1
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• pp.281-287
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• 2011

GFRP rebars could be deteriorated by concrete alkalinity. This paper focuses on the investigation of durability of GFRP rebars with ribs exposed to alkaline environment of concrete. It has been reported that the milled E-glass fibers in the ribs of GFRP rebar can increase bond strength between GFRP rebars and the concrete. In this study, the effect of milled alkaline resistant glass fibers (milled AR glass) and milled E-glass in the ribs on the durability of GFRP rebar is investigated through ISS tests and moist absorption tests of the bare rebar. To accelerate the effect of the alkalinity, high temperature($40^{\circ}C$) was applied. According to the test results, mix ratio of milled glass fibers in the ribs by weight had significant effect on durability of GFRP rebars with ribs. It is because that the high mix ratio may leads more voids in the ribs due to lower workability and formability. On the other hand, changing fiber type in the ribs from E-glass to AR-glass had no improvements on ISS strength of the GFRP rebar. Therefore, it is found that determination of proper mix ratio of milled glass fiber in the mixture for the formation of the ribs of the GFRP rebar is important.

• Journal of Embryo Transfer
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• v.18 no.3
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• pp.203-213
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• 2003

Examination of correlation between blood compositions and economic traits is very important to improve selection accuracy and predict performance ability of Hanwoo, which may be impacted into the determination of feeding management as well as marketing places. This study was aimed to provide possible procedures of Hanwoo improvement as of early individual selection based on the phenotypic correlation between blood compositions and economic traits using 866 of Hanwoo managed at National Livestock Research Institute. Phenotypic correlation between blood compositions and economic traits was estimated for steer and bulls. BUN in steer and albumin and IGF-1 in bull were highly correlated with 24 mo of weight. Average daily gain of 21 to 24 mo was highly correlated with calcium in steer and albumin in bull. Back-fat thickness and marbling score were highly correlated with BUN in steer and bull, and meat yield index was highly correlated with calcium in steer and testosterone in bull. However, BUN, which is highly correlated with meat quality, was negatively correlated with meat yield index in steer and bull.