• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.10
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• pp.520-526
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• 2015

The characteristics of gas-liquid Taylor (Slug) flow in a square micro-channel of $600{\sim}600{{\mu}m}$ were investigated experimentally in this paper. The test fluids were nitrogen and water. The liquid and gas superficial velocities were 0.01~3 m/s and 0.1~3 m/s, respectively. Bubble and liquid slug length, bubble velocity, and frequency were measured by analyzing optical images using a high speed camera. Bubble length decreased with higher liquid flow rate, which increased dramatically with higher gas flow rate. However, slug length did not vary with changes in inlet liquid conditions. Additionally, bubble velocities and frequencies increased with higher liquid and gas flow rates. It was found that measured bubble lengths were in good agreement with the empirical models in the existing literature, but slug lengths were not.

• Journal of Convergence for Information Technology
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• v.8 no.1
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• pp.89-94
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• 2018

Recently, interest and necessity for the insect industry has been increasing. Insects, which are referred to as the second food, are being used in various fields. Interest in mass production of insects has been increasing in various fields, and the need for research on environmental analysis for them is also increasing. In some countries in other developed countries, automated breeding systems have been developed that incorporate IoT. However, it is limited to be applied to many kinds of insects, and the price is so expensive that it has not been utilized in farm households. Therefore, we have carried out a study to make an optimal system that can be used practically in a farmhouse. Protaetia brevitarsis used for medicinal and edible purposes. It automatically checks the moisture of sawdust medium, which has the greatest influence on the environment of the slugs, which is the third larva of the grasshopper, and informs the result through the LED. It is applied to the environment to create an optimal breeding environment. I want to make it.

• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3635-3642
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• 2021

Natural circulation systems (NCSs) are extensively applied in nuclear power plants because of their simplicity and inherent safety features. For some passive natural circulation systems in floating nuclear power plants (FNPPs), the ocean is commonly used as the heat sink. Condensation induced water hammer (CIWH) events may appear as the steam directly contacts the subcooled seawater, which seriously threatens the safe operation and integrity of the NCSs. Nevertheless, the research on the formation mechanisms of CIWH is insufficient, especially in NCSs. In this paper, the characteristics of flow rate and fluid temperature are emphatically analyzed. Then the formation types of CIWH are identified by visualization method. The experimental results reveal that due to the different size and formation periods of steam slugs, the flow rate presents continuous and irregular oscillation. The fluid in the horizontal hot pipe section near the water tank is always subcooled due to the reverse flow phenomenon. Moreover, the transition from stratified flow to slug flow can cause CIWH and enhance flow instability. Three types of formation mechanisms of CIWH, including the Kelvin-Helmholtz instability, the interaction of solitary wave and interface wave, and the pressure wave induced by CIWH, are obtained by identifying 67 CIWH events.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.8 no.2
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• pp.95-101
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• 2022

Microfluidic radioimmunoassay (RIA) platform called µ-RIA spends less reagent and shorter reaction time for the analysis compared to the conventional tube-based radioimmunoassay. This study reported the design of µ-RIA chips optimized for the gamma counter which could measure the small samples of radioactive materials automatically. Compared with the previous study, the µ-RIA chips developed in this study were designed to be compatible with conventional RIA test tubes. And, the automatic gamma counter could detect radioactivity from the ¹²⁵I labeled anti-PSA attached to the chips. Effects of the multi-layer microchannels and two-phase flow in the µ-RIA chips were investigated in this study. The measured radioactivity from the ¹²⁵I labeled anti-PSA was linearly proportional to the number of stacked chips, representing that the radioactivity in µ-RIA platform could be amplified by designing the chips with multi-layers. In addition, we designed µ-RIA chip to generate liquid-gas plug flow inside the microfluidic channel. The plug flow can promote binding of the biomolecules onto the microfluidic channel surface with recirculation in the liquid phase. The ratio of liquid slug and air slug length was 1 : 1 when the ¹²⁵I labeled anti-PSA and the air were injected at 1 and 35 µL/min, respectively, exhibiting 1.6 times higher biomolecule attachment compared to the microfluidic chip without the air injection. This experimental result indicated that the biomolecular reaction was improved by generating liquid-gas slugs inside the microfluidic channel. In this study, we presented a novel µ-RIA chips that is compatible with the conventional gamma counter with automated sampler. Therefore, high-throughput radioimmunoassay can be carried out by the automatic measurement of radioactivity with reduced radiowaste generation. We expect the µ-RIA platform can successfully replace conventional tube-based radioimmunoassay in the future.

• Korean journal of applied entomology
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• v.52 no.4
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• pp.403-408
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• 2013

A survey of pest occurrence and status of farmer's pest management was conducted at 45 cymbidium farms in 10 major cultivation areas in Korea. The pest species collected from the cymbidium farms were identified as follows: Tetranychus urticae Koch, Frankliniella intonsa Trybom, Pinnaspis aspidistrae Signoret, Incilaria confusa Cockarel, Halyomorpha brevis Walker, Myzus persicae S$\ddot{u}$lzer, and Aphis gossypii Glover, Coccus hesperidum Linnaeus, Thrips flavus Schrank, and Thrips tabaci Lindeman. The two-spotted spider mite, T. urticae, was the key pest in cymbidium production, occurring on 45 farms, followed by scales (20 farms), slugs (6), thrips (8), aphids (5), and stinkbug (1). PCR-RFLP of the rDNA ITS2 region revealed that two thrips species, Thrips flavus Schrank and Thrips tabaci Lindeman, occur on cymbidium farms. Therefore, it is necessary for the cymbidium farmers to establish an integrated pest management system to meet quarantine standards.

• Current Research on Agriculture and Life Sciences
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• v.7
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• pp.127-151
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• 1989

The ground beetles or carabids are essentially predaceous feeding on a wide variety of insects including forest pests, slugs and land snails containing those injurious to livestock or veterinary, thus many are predominantly beneficial and serve as natural enemies. In the present investigation, some morphometric multivariate analysis were done for 9 different populations in 5 subspecies of D. (C.) jankowskii, which are one of the most common ground beetles in Korea As the results, when the comparison was conducted between intraspecific groups regardless of subspecies in external morphological characters, the average group membership revealed 97.46% correct assignment For intersubspecific comparisons alone 96.3% were correctly classified. Between the groups of ssp. jankowskii an average of 100% individuals were classified in their known group. Thus the predict group membership was highly significant(P<0.001), exceeding so-called 'the 75% rule'. Whereas, the average group membership using the male genitalic characters represented less than the 75% assignment, except only in ssp. quelpartianus (85.6%). The population from Is. Chindo were described here as a new subspecies for qualitative as well as the resultant quantitative differences. Therefore, a total of 7 subspecies are represented in Korea. Among them, the nominate subspecies, ssp. jankowskii(sensu lato), revealed distinct intrasubspecific differences between different geographic populations. These differences can be as notable as intersubspecific variation which need substantial revision of the previous intuitional concepts on the infraspecific level.

• Korean Chemical Engineering Research
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• v.58 no.4
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• pp.651-657
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• 2020

Fluidization processes in which solid particles vividly move like gas or liquid have been widely used in various industrial sectors, such as thermochemical energy conversion and polymerization processes for general purpose polymer resins. One of the general purpose polymer resins, LLDPE(Linear low-density polyethylene) resins have been produced in bubbling fluidized bed processes in the world. In a bubbling fluidization polymerization reactors, LLDPE particles with relatively larger particle size and low density are fluidized by hydrogen gas for polymerization reaction. Though LLDPE polymerization reactors are one of bubbling fluidization processes, slugs that have negative impact for reaction exist or occur in these processes. Therefore, the fluidization state of LLDPE particles was investigated in a simulation model similar to a pilot-scale polymerization reactor (0.38 m l.D., 4.4 m High). In particular, the effect of gas velocity (0.45-1.2 m/s), solid density (900-199 kg/㎥), solid sphericity (0.5-1.0), and average particle size (120-1230 ㎛), on bed height and fluidization state were measured by using a CPFD(Computational particle-fluid dynamics) method. With CPFD analysis, the occurrence of a flat slug was visualized. Also, the change in particle properties, such as particle density, sphericity, and size, could reduce the occurrence of slug and bed expansion.

• Nuclear Engineering and Technology
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• v.28 no.1
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• pp.1-16
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• 1996

In an effort to determine the combined effects of major parameters of heat exchanger tubes on the nucleate pool boiling heat transfer in the scaled in-containment refueling water storage tank (IRWST), a total of 1,966 data for q'quot; versus ${\Delta}T$ has been obtained using various combinations of tube diameters, surface roughness, and tube orientations. The experimental results show that (1) increased surface roughness enhances heat transfer for both horizontal and vertical tubes, (2) the two heat transfer mechanisms, i.e.,enhanced heat transfer for both horizontal and vertical tubes, (2) the two heat transfer mechanisms, i.e., enhanced heat transfer due to liquid agitation by bubbles generated and reduced heat transfer by the formation of large vapor slugs and bubble coalescence are different in two regions of low heat fluxes (q'quot; $\leq$50kW/$m^2)$ and high heat fluxes (q'quot; $\geq$50kW/$m^2)$ depending on the orientation of tubes and the degree of surface roughness, and (3) the heat transfer rate decreases as the tube diameter is increased for both horizontal and vertical tubes, but the effect of tube diameter on the nucleate pool boiling heat transfer for vertical tubes is greater than that for horizontal tubes. Two empirical heat transfer correlations for q'quot;, one for horizontal tubes and the other for vertical tubes, are obtained in terms of surface roughness $({\varepsilon})$ and tube diameter (D). In addition, a simple empirical correlation for nucleate pool boiling heat transfer coefficient $(h_b)$ is obtained as a function of heat flux (q'quot;) only.ucleate pool boiling heat transfer coefficient $(h_b)$ is obtained as a function of heat flux (q'quot;) only.

• Korean journal of applied entomology
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• v.49 no.4
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• pp.423-428
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• 2010

The species of land snails (Stylommatophora) that feed on perilla plants were observed under leaf perilla greenhouses cultivated in the Milyang and Busan areas. Four species of land snails were recorded. Among them, three species were slugs, Meghimatium bilineatum in Phlomycidae, Deroceras reticula tum, and Limax marginatus in Limacidae, and one species was the snail Acusta despecta sieboldiana in Bradybaenidae. D. reticulatum occurred most frequently followed by A. despecta sieboldiana, L. marginatus and M bilineatum. Annually, land snails showed two peaks in the middle of April and in late November for D. reticulatum, early May to middle November for A. despecta sieboldiana, and middle April and early November for L. marginatus. M bilineatum, however, did not show any clear peak because of its low population occurrence.

• Journal of Sericultural and Entomological Science
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• v.15 no.1
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• pp.37-48
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• 1973

The purpose of this studies is to improve the cohesion of raw silk through various analyses on cocoon drying, cooking, reeling, re-reeling, and on the properties of water. Also we investigated the correlation between silk testing items which we have reached to the following results. 1. Drying of cocoon When cocoons were slowly dried with 100$^{\circ}C$, the results of cohesion became much better. On the other hand, the results were considerably decreased in case the temperature with 115$^{\circ}C$. 2. Cooking of cocoon In case of the cooking of cocoon, we found that the result of cohesion was best with incomplete cooking, that of the control was next, while in over cooking, the results were very low. Also the results of cohesion were much better when using the method of over cooking with sericin arrestive agent than that of incomplete cooking with sericin agglutinating agent. 3. Reeling of cocoon A) When the temperature of reeling bath was 25-45$^{\circ}C$, the results of cohesion test were much better, but at the temperature below 25$^{\circ}C$ or above 45$^{\circ}C$, the results became worse. B) With out the process of croissieur, the results of cohesion were too bad, but in case of croissieur more than 1cm, cohesion became better rapidly. Further more, we understood that the results of cohesion were improving slightly with longer length of croissieur. C) When the velocity of reeling was increased, the results of cohesion also improved. The best results were shown when reeling velocity was 180-220 r.p.m. But when the velocity was increased more than 220 r.p.m., the results of cohesion got worse more or less. D) When the temperature of the drying pipe in reeling machine was raised, the results of cohesion also showed a tendency to improve. 4. Re-reeling A) We could net reach a conclusion as to have correlation between the number of dipping repeat in vacuum tank and the results of cohesion before re-reeling process. B) When we used Seracol 500 as an agglutination protective agent with l/1000 to l/2000 of water, the results of cohesion test were better. C) When we used Pearl-lite as an agglutination protective agent with 1/1000 to 1/2000 of water, the results of cohesion were considerably better. D) We gained tile best results when used Cohesion Improving Chemical, A-80, with 500-1500 times diluted. 1) Results of cohesion was improved when humidity was low or temperature was high in the rereeling machine. 5. Filature water A) The water pH near the isoelectric point of protein showed the best cohesion, but the farther water pH, the worser results were obtained. B) With the increasing of M-alkalinity in filature water, the results of cohesion were worse. Above all, we understood the tendency of the results of cohesion get worse when the M-alkalinity is increased above 200 ppm. C) By increasing the total hardness of the filature water, it improved the results of cohesion. Especially, when the total hardness was above 300ppm, the results were extremely high. 6. Effects combination of each results A) The result of effects combination in filature processes with the obtained best conditions was distinctively improved. But the results could not reach in mathematicaly double effect. When reelied under worse conditions, the results of cohesion test were too bad. There was "effect limit" for the promotion. B) Generally the results of cohesion were bad when the filature conditions(the temperature, pressure and the properties of water, etc) are processed as sericin loss to be high. On the other hand, the results were very good when lower sericin loss was controlled in filature conditions. C) When filature conditions such as reeling velocity and croissieur length provide pysical cohesion ability and when raw silk dry fast during reeling and re-reeling, we found the result of cohesion was better. 7. Correlation of silk testing items. A) A negative correlation exists between the results of cohesion test and cleanness defect. Another word, the result of cohesion test was found to be worse as cleanness defect increased. B) In cleanness, cohesion has negative correlation against the number of slugs, but we could not find any correlation against long loops, loose ends. C) Cohesion has negative correlation against average neatness and low neatness defect. The better the results of neatness respectively, the better the results of cohesion found. D) There is no correlation between tenacity and the results of cohesion test, but there was high positive correlation between the results of elongation and those of cohesion test. The more elongation, the better the results of cohesion was found.