• Tribology and Lubricants
• /
• v.38 no.2
• /
• pp.53-62
• /
• 2022

This study presents experimental measurements of the rotordynamic performance of a motor-driven small turbocompressor supported by gas beam foil journal bearings (GBFJBs) and compares the test results with the predictions of a computational model. The experiments confirmed that the rotational synchronous frequency component dominates the behavior of the overall rotor vibrations, whereas the nonsynchronous components are insignificant, indicating the rotor-bearing system remains stable up to 100 krpm. The undamped natural frequency and imbalanced response of the rotor-bearing system are predicted when integrating the finite element model of the rotor-bearing system with the predictions of the bearing dynamic coefficients. The results are in good agreement with the experimental results. In addition, base excitation test results show that the small turbocompressor can endure large external forces and demonstrate limited rotor amplitudes. A simple single degreeof-freedom rotor model using the nonlinear stiffness of the GBFJBs can effectively predict the test results.

• Journal of Ginseng Research
• /
• v.47 no.4
• /
• pp.572-582
• /
• 2023

Background: Free fatty acid-induced lipotoxicity is considered to play an important role in pancreatic β-cell dysfunction. The effect of ginsenosides on palmitic acid-induced pancreatic beta-cells cell death and failure of glucose-stimulated secretion of insulin (GSIS) was evaluated in this study. Methods: Enzyme-linked immunosorbent assay kit for a rat insulin was used to quantify glucose-stimulated insulin secretion. Protein expression was examined by western blotting analysis. Nuclear condensation was measured by staining with Hoechst 33342 stain. Apoptotic cell death was assessed by staining with Annexin V. Oil Red O staining was used to measure lipid accumulation. Results: We screened ginsenosides to prevent palmitic acid-induced cell death and impairment of GSIS in INS-1 pancreatic β-cells and identified protopanaxadiol (PPD) as a potential therapeutic agent. The protection effect of PPD was likely due to a reduction in apoptosis and lipid accumulation. PPD attenuated the palmitic acid-induced increase in the levels of B-cell lymphoma-2-associated X/B-cell lymphoma 2, poly (ADP-ribose) polymerase and cleaved caspase-3. Moreover, PPD prevented palmitic acid-induced impairment of insulin secretion, which was accompanied by an increase in the activation of phosphatidylinositol 3-kinase, peroxisome proliferator-activated receptor γ, insulin receptor substrate-2, serine-threonine kinase, and pancreatic and duodenal homeobox-1. Conclusion: Our results suggest that the protective effect of PPD on lipotoxicity and lipid accumulation induced by palmitic acid in pancreatic β-cells.

• International conference on construction engineering and project management
• /
• 2013.01a
• /
• pp.107-110
• /
• 2013

Recently, Korea parliament legislated the Low Carbon Green Growth Act (April, 2012) and approved a bill (May, 2012) to start carbon emission trading system in 2015. It means that for the first time, government would regulate the amounts of carbon emission in private entities, and private entities should attain predefined emission reduction goals by implementing clean development mechanism (CDM) project or buy the Certified Emission Reductions (CERs) from the trading market to avoid penalty. Under these circumstances, it is not easy for them to determine when or how to implement the CDM project because the governmental energy policies about the level of governmental subsidies, periods for free emission allocation, etc. are still under discussion and the future price of the CERs is quite uncertain. Thus, this study presents a real-option based model to assess the financial viability of the CDM project which switches bunker-C oil to liquefied natural gas (LNG). The proposed model is expected to assist private entities in establishing the investment strategy for CDM project under uncertain government energy policies.

• Journal of Aquaculture
• /
• v.11 no.3
• /
• pp.381-390
• /
• 1998

Three feeding experiments were carried out to evaluate the effects of fatty acids or lipid sources in diets on the survival, growth and body composition of junenile abalone(Haliotis discus hannai). Diets used in this study contained casein or fish meal as a protein source. Three replicate groups of abalone averaging 160 mg were fed with casein diets containing 12:0, 18:1, 18:2n-6, 18:3n-3, n-3HUFA, squid liver oil (SO), corn oil (CO), beef tallow (BT), SO+CO, and SO+BT, or fed fish meal diets containing SO, CO, BT, SO+CO, SO+BT and not supplemental oil for 20 weeks, respectively. Survival rate, weight gain and soft body weight of abalone were not significantly affected by different fatty acids in the casein diets (P>0.05). Weight gain, soft body weight and shell length of abalone fed the casein diets containing SO, SO+CO or SO+BT were significantly higher (P<0.05) than those of abalone fed the casein diets containing CO or BT. Survival rate of abalone fed the fish meal diets was not influenced by different lipid sources (P>0.05). Weight gain and soft body weight of abalone fed the fish meal diets containing beef tallow (BT or SO+BT diet) were lower than those of abalone fed the diet not added oil or diets containing SO, CO and/or SO+CO(P<0.05). These data indicated that SO or SO+CO was good dietary lipid source for juvenile abalone, and that these oil supplement in diet was not necessary when fish meal was used as a protein source.

• Applied Biological Chemistry
• /
• v.26 no.4
• /
• pp.261-265
• /
• 1983

The changes in fatty acid compositions of the each fraction of oil, that is, steryl ester, triglyceride, diglyceride and free fatty acid, were analyzed during the storage of sesame seed for 4, 9, and 15 months at four different storage conditions, that is, storage under light with linen pouch(LA), storage in dark with linen pouch(DA), storage under light with poly ethylene pouch(LS), and storage in dark with poly ethylene pouch(DS). In the fatty acid composition of steryl ester fraction, palmitic and stearic acid were decreased but linoleic acid was increased during the storage in all the storage conditions. The ratio of $C_{18}$ to $C_{16}$ fatty acids in steryl ester from DA and LA was higher than that from DS and LS during storage until 15 months. The palmitic and stearic acid content in triglyceride were decreased until 9 months of storage, then slightly increased until 15 months of storage in all the storage conditions, but reverse tendency was observed in the lineoleic acid content. The ratio of $C_{18}$ to $C_{16}$ fatty acids and unstaturated to saturated fatty acids in DS were slightly higher than these in DA and LA. In the fatty acid composition of free fatty acid, the content of palmitic and stearic acid were decreased until 9 months of storage, then increased until 15 months, but reverse tendency was observed in the oleic and linoleic acid: the ratio of unsaturated to staturated fatty acids in DA and LA was higher than that in DS and LS during the storage for 15 months.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.23 no.10
• /
• pp.1265-1273
• /
• 1999

PIV(Particle Image Velocimetry) velocity field measurements inside the snout of a1/10 scale model of the Zn plating process were carried out at the strip speed $V_s=1.5m/s$. Aluminum powder particles ($1{\mu}m$) and atomized olive oil ($3{\mu}m$) were used as seeding particles to simulate the molten Zinc flow and deoxidization gas flow, respectively. A pulsed Nd:Yag laser and a $2K{\times}2K$ high-resolution CCD camera were synchronized for the PIV velocity field measurement. From flow visualization study, it is found that the liquid flow in the Zn pot is dominantly governed by the uprising flow caused by the rotating sink roll, with its effect on the steel strip inside the snout largely diminished by installing of the snout. The deoxidization gas flow in front of the strip inside the snout can be characterized by a large-scale vortex rotating clockwise direction formed by the moving strip. In the rear side of the strip, a counter-clockwise vortex is formed and some of the flow entrained by the moving strip impinges on the free surface of molten zinc. The liquid flow in front of the strip is governed by the flow entering the snout, caused by the spinning sink roll. Just below the free surface a counter-clockwise vortex is formed near the snout wall. The moving strip affects dominantly the flow behind the strip inside the snout, and large amount of the liquid flow follows the moving strip toward the sink roll. The thickness of the flow following the strip is very thin in the front side due to the uprising flow, however thick boundary layer is formed in the rear side of the strip. Its thickness is increased as moving downstream toward the sink roll. Inside the snout, the deoxidization gas flow above the free surface is much faster than the liquid flow in the zinc pot. Due to the larger influx of the flow following the moving strip in the rear side of the strip, higher percentage of imperfection can be anticipated on the rear surface of the strip.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.20 no.6
• /
• pp.520-528
• /
• 1987

Quality stability of roasted lavers during heat treatment and storage was investigated measuring the changes in pigments including chlorophyll a, carotenoids and biliproteins, fatty acids and free amino acids as the major quality factors. In roasting of fried lavers, carotenoids were found to lie more stable than chlorophyll a, and biliproteins were most heat labile. The overall heat stability of the pigments depended upon heating time and temperature. Chlorophyll a and carotenoids were retained more than $90\%$ in the casts of roasting for 90 min. at $60^{\circ}C;\;60min.\;at\;80^{\circ}C;\;10\;min.\;at\;100^{\circ}C;\;or\;5min.\;at\;150^{\circ}C$ while biliproteins remained about $70\%$. The lipids of dried lavers including polyunsaturated fatty acids appeared rather heat stable when compared to the stability of pigments under the same conditions of roasting. Spray of sesame oil or seasoning solutions on the surface of lavers after roasting seemed desirable for stabilizing pigments and free amino acids during storage particularly at low water activity. And that was also benefit for the protection of polyenoic fatty acids from rapid progress of oxidation during storage. Free amino acids were reduced fast during roasting, especially most of threonine and glycine while glutamic acid was rapidly lost during the storage.

• Korean Journal of Food Science and Technology
• /
• v.32 no.1
• /
• pp.25-30
• /
• 2000

Phytoestrogen has been used as a suppliment of estrogen in order to treat osteoporosis. The representative phytoestrogens, isoflavones, are daidzein, genistein and formononetin which were present highly in our traditional soybean foods. The quantitative analysis of the isoflavone was done with a high performance liquid chromatography(HPLC) using a UV/VIS detector for the contents of the isoflavones in Astragali Radix, soybean sprouts, bean-curd(Tofu), soybean, soybean oil, pea, kidney pea, black bean(Yak-kong), soybean sauce(Ganjang). soybean paste(Doenjang), and fermented soybean(Maejoo). The content of free daidzein in soybean sprouts was $43.49{\pm}3.41\;mg/kg$$ which was much higher than that in soybean, $14.52{\pm}0.58\;mg/kg$, although total daidzein of fermented soybean was lower than that in soybean (Table 2. P<0.01). The amounts of free genistein in soybean sprouts, fermented soybean. and soybean paste were $27.63{\pm}1.66\;mg/kg,\;291.52{\pm}6.81\;mg/kg,\;and\;18.75{\pm}1.33\;mg/kg$, respectively. The level of free formononetin in soybean paste was the highest among the soybean products (P<0.01). The content of formononetin in Aatragali Radix, $9629.73{\pm}0.57\;{\mu}g/kg$, was about 160 times higher than that in soybean. Thus Korean traditional soybean products, black bean(Yak-Kong) and Astragali Radix can be a good choice of phytoestrogens.

• Applied Biological Chemistry
• /
• v.26 no.2
• /
• pp.90-96
• /
• 1983

To study the composition of silkworm pupae oil, lipid of silkworm pupae was separated into two fractions, ether extractable and 85% methanol extractable, and the lipid components of each fraction were analyzed by using silicic acid column, thin layer chromatography and gas chromatography. Silkworm pupae contains 35.4% crude fat (dry-basis) of which consists 34.4% diethyl ether-extract and 0.9% of 85% methanolextract. The diethyl ether-extract contained 96.1% of neutral lipid, 2.9% of glycolipid and 1.0% of phospholipid while methanol-extract was consisted of 47.4% of neutral lipid, 14.6% of glycolipid and 38.1% of phospholipid. The major components of phospholipid were phosphatidyl glycol(41.0%), and phosphatidyl choline(28.2%) and phosphatidyl ethanolamine(21.2%) in the diethyl ether-extract and phosphatidyl glycol(48.4%), phosphatidyl inositol(22.8%) and phosphatidyl choline(17.9%) in the methanol-extract. The major fatty acids of the total lipid were oleic acid(33.5%), linolenic acid(31.0%) and palmitic acid(23.1%).

• Journal of Life Science
• /
• v.29 no.2
• /
• pp.147-151
• /
• 2019

Soybean [Glycine max (L.) Merr.] is grown worldwide for its high protein and oil content. Anthocyanins from black soybean seed coats are known to have many pharmaceutical effects. Soybean cultivars with large seed sizes and black seed coats are needed by soybean farmers. However, antinutritional factors, like protein, stachyose, and Kunitz trypsin inhibitor (KTI) exist in raw mature soybeans. Genetic elimination or reduction of these components is needed in soybean breeding. The objective of this research was to develop new a soybean strain with black seed coats and green cotyledons that was KTI protein free and low in stachyose. Six parents were used. The presence or absence of KTI protein was detected using the Western blot technique. The content of stachyose in mature seeds was detected using HPLC. One new strain was selected from 11 $F_2$ plants with black seed coats and green cotyledons that lacked KTI protein. The new strain had black seed coats and green cotyledons and was KTI protein free and low in stachyose. The plant height of the new strain was 66 cm, and its 100-seed weight was 28.4 g. The stachyose content of the new strain was 2.59 g/kg. The new strain developed in this research will be used to develop new cultivars that are KTI protein free and low in stachyose.