• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.1
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• pp.5-14
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• 2003

Cutting fluids used for superfinishing are usually mineral based oils With sulfur and chlorine additives. These cutting fluids are an environmental hazard and can adversely affect the health of personnel on the shop floor. The present investigation was undertaken to explore the possible alternative use of environmentally-conscious cutting fluids for superfinishing. Unlike mineral oils, these environmentally-conscious cutting fluids are biodegradable and non-hazardous. Experiments were conducted for testing an ester oil manufactured by Accu-Lube applied in miniscule amounts using the Minimum Quantity Lubrication (MQL) technique. A significant improvement in stock removal was found with the 6 stones tested. The specific energy values associated with the process were also significantly lower than those obtained previously with conventional straight oils and the water based synthetic fluid, indicative of better lubrication, while the surface roughness was comparable. These tests prove that MQL with ester oils can be a very effective environmentally-conscious alternative to conventional straight oils.

• Journal of the Korean Magnetics Society
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• v.11 no.5
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• pp.217-221
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• 2001

We made magnetite which was prepared with mixed liquids of Fe$\^$2+/and Fe$\^$3+/ added to the 3N-NaOH by coprecipitation reaction. Ahead of making magnetite, we investigated variation of physical properties for changing Fe$\^$2+/ : Fe$\^$3+/. Through the variation of the process temperature, we examined physical properties of magnetite. Also, to examine possibility of magnetic fluids, from magnetite manufactured in this way, we examined the crystal structure by X-ray diffraction pattern. The saturated magnetization $\sigma$$\_$s/, value has 60.8 emu/g, when Fe$\^$2+/ to Fe$\^$3+/ ratio is 0.46 : 0.54 in the synthetic magnetite. Keeping the condition, when the synthetic temperature is kept at 80$\^{C}$ for 30 minutes, we get $\sigma$$\_$s/, value 63.51 emu/g. It shows that $\sigma$$\_$s/, value is bigger as the synthetic temperature is higher.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1995.06b
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• pp.1-3
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• 1995

Aspects of the current trend in lubricants and future challenges are discussed. The discussion highlights key enviromnental issues regarding to resource conservation, toxicological consideration and environmental acceptability. Also highlighted are base stocks trends relative to hydroprocessed stocks (HVI, VHQ and XHQ), synthetic base stocks (PAO and organic esters) and biodegradable fluids (vegetable oils and special esters). Equipment severity and lubricant performance quality are briefly described.

• YAKHAK HOEJI
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• v.30 no.4
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• pp.198-201
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• 1986

The successful elucidation of the opiate receptor and its natural ligands has generated speculation that other drugs might interact with cellular sites designed to accommodate endogenous mediators. The properties of binding sites for the cardiac glycosides(CG), together wit the potency and specificity of the digitalis drugs suggest that CG mimic an endogenous digitalis-like factor. Recenthy, several laboratories have reported the potency in mammalian tissues and fluids of unidentified materials that share certain specific propeties of the CG. Identification of body's own digitalis might yield a natural co pound whose synthetic analogs may provide safer and more effective drugs than can be achieved by structural edification of the CG of plant origin.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.1
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• pp.1-7
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• 2014

Nanofluids, suspending nano-particles of various materials, have a good heat transfer characteristics compared with pure base fluids. For the reason, nanofluids have been considered as one of the measure to improve energy efficiency, and studied to apply on a working fluid of a high performance heat exchanger. This study tested thermal conductivities of nanofluids applying diamond nano-powder on DI water, ethylene glycol, and ethyl alcohol. Nanofluids are fabricated by matrix synthetic method, and the volume percent of diamond nano-powder contained in the base fluid are 0.1, 0.3, 0.5, and 1vol%. As a result, thermal conductivities are enhanced with applying diamond nano-power. Especially, the conductivity is highly increased up to 23% at 1vol% nanofluid applying diamond nano-powder on DI water.

• Journal of Advanced Marine Engineering and Technology
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• v.6 no.2
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• pp.21-41
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• 1982

Viscosity, especially characteristic among various properties of visco-elastic fluids such as high polymer solutions, is affected mainly by temperature and concentration. Hence, it is important for fluid engineering to express, by some equations, how the fluid characteristics vary with the change of temperature and concentration and to analyze them to obtain consistent viscous characteristics. High polymer solutions, synthetic products of modern chemical industry, suggest many interesting investigations because they are typical visco-elastic materials. Experimentation was made to derive some useful fluid characteristic equations of SEPARAN-NP10 (polyacylamide) expressed by n (flow behavior index) and K' (consistency index) when it is given temperature and concentration variation. To measure viscosity, capillary viscometer was adopted and the range of experimentation is 0-2,000 P.P.M. in concentration and 15-55 .deg.C in temperature. The experimental results are summarized as follows: The flow behavior index n 1) has nearly constant results irrespective of temperature variation at same conentration and the results are shown in (Table. 4-4-3) 2) has following equation, regardless of temperature, for the variation of concentration. n=-1.0765*10$^{-4}$ P+0.9915 (P:P.P.M.) The consistency index K' 1) has different results for the variation of temperature at same concentration and the results are given in (Table.4-7-2) 2) has following equation for the variation of concentration at same temperature. log 10$^{4}$K' =6.4785*10$^{-4}$ P-1.0529 (P:P.P.M)

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.2
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• pp.91-100
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• 2006

The purpose of this study was to validate alternative method by using non-carcinogenic, and less toxic solvents than NIOSH analytical method 5524 for measuring the airborne MWFs in workplaces. In laboratory tests, the ETM solvents(mixture of same volume for ethyl ether, toluene, and ethanol) were selected. The alternative method of analyzing MWFs, referred to as the ETM solvent extraction method, showed 0.04 mg/sample as LOD, and 0.15 mg/sample as LOQ. The analytical precision (pooled CV, coefficient of variation) of the ETM solvent extraction method for analyzing the straight, soluble, semisynthetic, and synthetic metalworking fluid was 1.5%, 2.0%, 2.6%, 1.6%, respectively, which was similar to the precision (2.6%) of NIOSH analytical method (NIOSH 0500) for total dust. The analytical accuracy by recovery test, spiked mass calculated as extractable mass, was almost 100%. As the result of storage stability test, metalworking fluid samples should be stored in refrigerated condition, and be analyzed in two weeks after sampling. The 95% confidence limit of the estimated total standard error for the ETM solvent extraction method for analyzing the straight, soluble, semisynthetic, and synthetic metalworking fluid was ${\pm}12.6%$, ${\pm}12.5%$, ${\pm}14.0%$, and ${\pm}13.6%$, respectively, which satisfied the OSHA sampling and analytical criteria.

• Journal of Animal Reproduction and Biotechnology
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• v.37 no.1
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• pp.2-12
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• 2022

Extracellular vesicles (EVs) are nanovesicles that carry bioactive cargoes of proteins, lipids, mRNAs, and miRNAs between living cells. Their role in cellular communication has gained the attention of several research reports globally in the last decade. EVs are critically involved in sperm functions, oocyte functions, fertilization, embryonic development, and pregnancy. The review summarizes the state-of-the-art of EVs research in the diagnostic and therapeutic (theranostic) potentials of the EVs during the pregnancy that might provide a solution for gestational disturbances such as implantation failure, maternal health problems, gestational diabetes, and preeclampsia. EVs can be found in all biological fluids of the fetus and the mother and would provide a non-invasive and excellent tool for diagnostic purposes. Moreover, we provide the current efforts in manufacturing and designing targeted therapeutics using synthetic and semi-synthetic nanovesicles mimicking the natural EVs for efficient drug delivery during pregnancy.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3199-3205
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• 2013

The inclusion behavior of sulfobutylether-${\beta}$-cyclodextrin (SBE-${\beta}$-CD) with perphenazine (PPH) was first studied by flow injection (FI)-chemiluminescence (CL) analysis with proposed $lg[(I_0-I_s)/I_s]=lgK_{P-CD}+nlg[C_{PPH}]$ model and molecular docking. Results showed that a 1:1 complex of SBE-${\beta}$-CD/PPH could online form, with the formation constant $K_{P-CD}$ of $2.57{\times}10^7Lmol^{-1}$ at 298 K. The thermodynamic parameters showed that the inclusion behavior of SBE-${\beta}$-CD/PPH was a spontaneous process by hydrophobic interaction. The molecular docking results revealed PPH entered into the larger cavity of SBE-${\beta}$-CD with two hydrogen bonds. Based on the linear relationship of the decrement of luminol/SBE-${\beta}$-CD/PPH CL intensity against the logarithm of PPH concentration ranging from 0.03 to 30.0 ng $mL^{-1}$, the present FI-CL analysis using luminol/SBE-${\beta}$-CD/PPH system was successfully applied to PPH determination in biological fluids and tablets with recoveries from 94.5 to 105.6% and RSDs less than 2.6% (n = 5).

• Journal of Mechanical Science and Technology
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• v.20 no.4
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• pp.554-560
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• 2006

This paper describes the demonstration of successful fabrication and initial characterization of micromachined pressure sensors and micromachined jets (microjets) fabricated for use in macro flow control and other applications. In this work, the microfabrication technology was investigated to create a micromachined fluidic control system with a goal of application in practical fluids problems, such as UAV (Unmanned Aerial Vehicle)-scale aerodynamic control. Approaches of this work include: (1) the development of suitable micromachined synthetic jets (microjets) as actuators, which obviate the need to physically extend micromachined structures into an external flow; and (2) a non-silicon alternative micromachining fabrication technology based on metallic substrates and lamination (in addition to traditional MEMS technologies) which will allow the realization of larger scale, more robust structures and larger array active areas for fluidic systems. As an initial study, an array of MEMS pressure sensors and an array of MEMS modulators for orifice-based control of microjets have been fabricated, and characterized. Both pressure sensors and modulators have been built using stainless steel as a substrate and a combination of lamination and traditional micromachining processes as fabrication technologies.