• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.39 no.8
• /
• pp.677-682
• /
• 2015

We simulate an emulsion system under simple shear rates to analyze its rheological characteristics using the lattice Boltzmann method (LBM). We calculate the relative viscosity of an emulsion under a simple shear flow along with changes in temperature, shear rate, and surfactant concentration. The relative viscosity of emulsions decreased with an increase in temperature. We observed the shear-thinning phenomena, which is responsible for the inverse proportion between the shear rate and viscosity. An increase in the interfacial tension caused a decrease in the relative viscosity of the decane-in-water emulsion because the increased deformation caused by the decreased interfacial tension significantly influenced the wall shear stress.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.23 no.4
• /
• pp.36-41
• /
• 2015

The cyclone separator is a simple device, which causes the centrifugal separation of materials such as droplets or particles in a fluid stream. The cyclone separator utilizes the energy obtained from fluid pressure and linear motion to create rotational fluid motion. This rotational motion leads the materials suspended in the fluid to separate from the fluid quickly due to the centrifugal force. The rotation is produced by the tangential or involuted introduction of fluid into the vessel. These materials may be droplets of fuel in blow-by gas through an engine. Droplets suspended in the feed liquid may separate according to size, shape, or density. And the change of part dimension in a cyclone separator can yield the its performance variation. The current study shows the influence of design parameters on the performance of a cyclone separator for blow-by gas.

• Research in Plant Disease
• /
• v.18 no.3
• /
• pp.250-254
• /
• 2012

In July 2011, hundreds of garden cosmos (Cosmos bipinnatus) were found to be infected with a white smut in Namyangju. Further surveys in central Korea showed that the disease occurred in all the nine localities visited, with disease incidence rate of >50%. Symptoms manifested as pale-green to chlorotic areas on the leaves, followed by white mildew development on lesions. The lesions usually coalesced and became necrotic, considerably reducing the aesthetic value. Caespituli were initially hypophyllous but later epiphyllous as well. Conidiophores were 10-40 in moderately dense fascicles, hyaline throughout, mostly guttulate, $20-45{\times}2-4{\mu}m$, obtuse at the apex, and had inconspicuous conidial scars. Conidia were solitary, botuliform, hyaline, aseptate, mostly guttulate, apex rounded, base rounded to truncate, $17-24{\times}3.5-5{\mu}m$, hilum inconspicuous, unthickened, and not darkened. Sori were rounded to elongated, resulting in first white and later brown leaf spots. Teliospores embedded in the leaf tissue were subglobose to ellipsoidal, subhyaline to pale yellowish-brown, $12.5-20{\times}10-15{\mu}m$. These morphological characteristics corresponded with those of Entyloma cosmi V$\acute{a}$nky, Horita & Jage. This is the first report of white smut disease of garden cosmos due to infection of E. cosmi in Korea.

• Tribology and Lubricants
• /
• v.24 no.6
• /
• pp.320-325
• /
• 2008

The recent industrial application requires technical methods to get the cutting fluid droplet surfaces in particular from the viewpoint of topography and micro texture. To characterize the surface topography of droplet, the combination of the confocal laser scanning microscope (CLSM) and wavelet filtering is well suited for obtaining the droplet geometry encountered in tribological research. This technique indicates a better agreement in obtaining an appropriate droplet surface obtained by the CLSM over a detail range of surface accuracy (resolution: $2{\mu}m$). And the results allow an excellent accuracy in a measurement of a droplet surface. The combination of extended focal depth measurement configured and multi-scale wavelet filtering has proven that it can construct a droplet surface in a successive and accurate way. A multi-scale approach of wavelet filtering was developed based on the decomposition and reconstruction of droplet surface by 2D wavelet transform using db9 (a mother wavelet of daubechies). Also this technique can be extended to characterize the quantification of droplet properties and other field in a wide range of scales. Finally this method is verified to be a better droplet surface modeling in a micro scale arising in a mist machining.

• Korean Journal of Ichthyology
• /
• v.35 no.4
• /
• pp.361-365
• /
• 2023

On May 12, 2023, a juvenile specimen (37.6 mm in standard length) belonging to the order Aulopiformes was collected from southern Yokjido, Tongyeong, Korea, using a Bongo net. The specimen was identified as the member of the family Scopelarchidae in having a slender body, a large mouth, large tube-like eyes, a long anal fin base, a developed adipose fin and no photophores on body. Finally, we identify the specimen as Scopelarchoides danae Johnson, 1974 in having 8 dorsal fin rays, 20 pectoral fin rays, 9 pelvic fin rays, 26 anal fin rays, dorsal fin located anteriorly than pelvic fin, and two large pigments below the pectoral fin and posterior to the pelvic fin. Scopelarchoides danae is distinguished from Scopelarchoides signifer in having less dorsal fin rays (8 vs. 9~10) and pectoral fin rays (20 vs. 22~25). The species differs from Scopelarchus guentheri and Scopelarchus analis in that it has no stripes along the both upper and lower of lateral line, and from Scopelarchus michaelsarsi in that it has more anal fin rays (26 vs. 18~21). Because this is the first occurrence among Korean fish fauna, we present its detailed morphological traits, and its new Korean name as "Nun-bang-ul-mae-tung-i".

• Korean Journal of Food Science and Technology
• /
• v.53 no.4
• /
• pp.365-374
• /
• 2021

In this study, the effect of enzyme-modified starch used in the preparation of filled hydrogel powder loaded with curcumin (FHP) on redispersibility, thermal and UV stability, and curcumin retention during in vitro digestion was investigated. FHP maintained stability without layer separation when redispersed and showed more stability against UVB than the emulsion powder (EMP). There was no significant difference in the chemical stability of curcumin between rice starch-based filled hydrogel powder (RS-FHP) and enzyme-modified starch-based filled hydrogel powder (GS-FHP). However, the gel matrix of GS-FHP maintained greater stability of lipid droplets in the stomach compared to RS-FHP, thereby improving the retention rate of curcumin after in vitro digestion. GS-FHP could be used as a novel material for developing premixes that require stable formulation and maintenance of functional substances, as it can increase the dispersion stability and retention rate of functional substances after digestion.

• Korean Journal of Plant Taxonomy
• /
• v.47 no.1
• /
• pp.51-93
• /
• 2017

Eastern coastal lagoons are a particular type of estuarine systems where seawater mixes with fresh water from their catchments. With the development of aquatic vegetation, this area shows high level of biodiversity. The purpose of this study is to produce a strategy for the comprehensive conservation of the vegetation of coastal lagoons through studies of the floristics and plant species compositions in 17 eastern coastal lagoons in Korea. Vascular plants were collected 109 times, from June of 2010 to November of 2014. The results showed that there were 720 taxa in total, including 118 families, 378 genera, 655 species, 13 subspecies, 46 varieties, and 6 hybrids. Korean endemic species numbered 11 taxa, and vascular plants listed in the red list according to the International Union for Conservation of Nature (IUCN) numbered 18 taxa. Indicator species of fourth (IV) and fifth (V) degree, as specified by floristic subregions, numbered 23 taxa. Among the species investigated in this survey, there were 4 taxa of plants of southern origin and 8 taxa of plants of northern originin the Korean peninsula. Several rare plants, Thermopsis lupinoides, Ligusticum hultenii, Mitrasacme alsinoides, Utricularia australis, Juncus fauriei, Carex vesicaria, and Puccinellia kurilensis, were distributed in eastern coastal lagoons. In all, 96 alien plants were recorded in the investigated area. The coastal lagoons on the eastern coast of Korea showed high plant diversity with many rare plants and phytogeographically important plants. Conservation strategies to ensure biodiversity and effective management of coastal lagoons are discussed in detail.

• Tuberculosis and Respiratory Diseases
• /
• v.43 no.6
• /
• pp.965-975
• /
• 1996

Background : Exogenous lipoid pneumonia is caused by inhalation or aspiration of animal, vegetable or mineral oil. Most cases are ascribed to aspiration of oil in laxatives or nose drops Petroleum, another pure hydrocarbon used as a base in various medications, is occasionally involved. Especially animal oil produces severe tissue inflammatory reaction, but most patients present with only abnormal chest X-ray and no specific clinical symptoms or signs. Method: Seven patients, 3 males and 4 females, with exogenous lipoid pneumonia, who was hospitalized or referred to pulmonary division at Samsung Medical Center from December 1994 10 July 1996, were included. They hadn a history of laking shark liver oil(so-called "squalene") for varying period of time. We reviewed clinical, radioloic and pathologic findings. Result: Patients look 7 to 30 capsules of "squalene" a day for at least one month to 5 years. Six cases had chronic disease such as diabetes, hypertension, or cerebrovascular accident. Respiratory symptoms of mild fever, cough and sputum were present in 3 cases and in 3 cases there was no clinical symptoms and signs but abnormal findings by chest X - ray. The major radiologic findings by simple chest X - ray and computed tomography consisted of consolidation, infiltration involving mainly right middle and both lower lobes, and ground-glass opacity. Five of six bronchoscopic examinations demonstrated both lipid droplets floating on the surface of bronchoalveolar lavage fluid and Lipid-laden macrophages in bronchoalveolar lavage fluid or lung tissue. Follow-up chest X -ray showed improvement in 4 cases but no marked interval change in 3 cases after removal of exposure to "squalene". Conclusion: Shark liver oil can induce lipoid pneumonia in adults. In case of high clinical suspicion, confirmation of "squalene" use by careful history taking is required and bronchoscopy is helpful in diagnosis.