• Reproductive and Developmental Biology
• /
• 제32권3호
• /
• pp.147-152
• /
• 2008

The aim of this study was to investigate what components of porcine epididymal fluid (pEF) influences the nuclear maturation of porcine germinal vesicle oocytes. Porcine cumulus-oocytes complexes from follicles were cultured in TCM 199 containing pEF. After 48 h cultures, oocytes were examined for evidence of GV breakdown, metaphase I, anaphase-telophase I, and metaphase II. Maturation rate of oocytes was significantly increased in media supplemented with 10% pEF during in vitro maturation (IVM) than in those without pEF. When lipid component of pEF was removed by treating n-heptane, no significant difference was observed in maturation of oocytes between n-heptane treatrment and intact pEF group. However, the proportion of oocytes reaching at metaphase II (M II) was significantly (p<0.05) decreased in the oocytes cultured in media containing trypsin-treated pEF compared to those in media with intact pEF. When porcine GV oocytes were matured in the medium supplemented with intact pEF or pEF heated at $56^{\circ}C$ and $97^{\circ}C$, rates of oocytes remained at GV stage were 11.7%, 29.4% and 42.0%, respectively. However, there were no difference in proportion of oocytes reaching at MII stage among intact pEF group and $56^{\circ}C$ group. Present study suggests that 1) pEF contains an enhancing component(s) for nuclear maturation in vitro of oocytes, 2) protein(s) of pEF may be capable to promote nuclear maturation in vitro, and 3) enhancing component for nuclear maturation may consist of two factors, which are responsible for germinal vesicle breakdown (GVBD) and promotion of MII stage.

• Fire Science and Engineering
• /
• 제32권5호
• /
• pp.34-39
• /
• 2018

In this study, the experiment conditions for the variation of heat release rate in compartment space were constructed to analyze the effects of fire spread and the operation time of sprinkler in accordance with the heat loss of the sprinkler's heat element. The compartment composed of fire board (width = 0.3 m, height = 0.5 m, length = 3.0 m), are manufactured to measure the temperature distributions in the inner space, the mass loss rate and heat release rate during the experiment of N-heptane pool fire test. Also, the operation time of sprinkler is analyzed with the installation of sprinkler and C-factor using Fire Dynamics Simulator Ver.6 under the experiment conditions. The results show that the operation time of sprinkler, which has RTI $100(m{\cdot}s)^{0.5}$ operating temperature $70^{\circ}C$, is 30 s~60 s for C-factor = 0 and 1, 62 s~92 s for C-factor = 3, and 120 s over for C-factor = 5, respectively.

• Journal of the Korean Society for Railway
• /
• 제11권3호
• /
• pp.294-299
• /
• 2008

The present study investigates the ventilation effects on smoke spreading with the rescue stations. Experiments for tunnel fires were carried out for n-heptane pool em at different fire locations, and the heat release rates (HRR) were obtained by addition, using the commercial code (FLUENT), the present article presents numerical results for smoke behavior in railway tunnels with rescue station, and it uses the MVHS (Modified Volumetric Heat Source) model for estimation of combustion products resulting from the fire source determined from the HRR measurement. As a result, it is found that smoke propagation is prevented successfully by the fire doors located inside the cross-passages and especially, the smoke behavior in the accident tunnel can be controlled through the ventilation system because of substantial change in smoke flow direction in the cross-passages.

• Fire Science and Engineering
• /
• 제31권4호
• /
• pp.43-51
• /
• 2017

In this study, new design fire curves were suggested for the utilization in fire simulations. Numerical simulations with the Fire Dynamics Simulator (FDS) were performed for the n-octane and n-heptane pool fires in the ISO 9705 compartment to evaluate the prediction performance of the previous quadratic, exponential design fire curves and newly suggested ones. The numerical results were compared with the experimental temperature and concentrations of $O_2$ and $CO_2$. The numerical results with the previous quadratic and exponential curves showed slow increase and decrease trend than experiments. However, the numerical results with the newly suggested 2 design fire curves showed more similar variation trend in temperature, $O_2$ and $CO_2$ concentrations than the quadratic and exponential curves. It was found that the newly suggested design fire curves can be possibly used in the numerical simulation of fires in a practical respect.

• Journal of the Korean Chemical Society
• /
• 제29권3호
• /
• pp.233-238
• /
• 1985

The non-porous and porous polystyrene divinylbenzene copolymers were prepared by the suspension polymerization method. The non-porous aminated polystyrene divinylbenzene, N-APSTDVB and the porous aminated polystyrene divinylbenzene, P-APSTDVB of 50∼100mesh size weakly basic anion exchanger were synthesized by chloromethylation followed by amination with methylamine. The functional groups of these synthesized anion exchangers were confirmed by their infrared spectra. The maximum capacity of these exchangers was 4.86meq/g. Pore volume and pore spectra were determined with a mercury porosimeter. The pore volume of P-PSTDVB increased with increasing X$_{diluent}$ at 30% of divinylbenzene. However, the pore volume of P-PSTDVB increased with increasing volume percent of divinylbenzene at constant mole fraction of diluent, X$_{diluent}$ of 0.5. The pore volume of synthesized copolymer and anion exchanger at 8% divinylbenzene and 0.5X$_{heptane}$ decreased as follows; P-PSTDVB 〉P-APSTDVB 〉N-PSTDVB. This result was attributed to the possibility that the pore volume were reduced by amination reactions. The distribution coefficients of boric acid on the N-APSTDVB anion exchanger in various concentrations of alcohol water solutions showed that as alcohol concentration increased, the distribution coefficients values decreased due to the reduced concentration of H$_2$BO$_3^-$.

• Membrane and Water Treatment
• /
• 제10권5호
• /
• pp.361-372
• /
• 2019

Effect of different alkane based solvents on the stability of emulsion liquid membrane was investigated using normal alkanes (n-hexane, n-heptane, n-octane and n-decane) under various operating parameters of surfactant concentration, emulsification time, internal phase concentration, volume ratio of internal phase to organic phase, volume ratio of emulsion phase to external phase and stirring speed. Results of stability revealed that emulsion liquid membrane containing n-octane as solvent and span-80 (5 % (w/w)) as emulsifying agent presented the highest amount of emulsion stability (the lowest breakage) compared with other solvents; however, operating parameters (surfactant concentration (5% (w/w)), emulsification time (6 min), internal phase concentration (0.05 M), volume ratio of internal phase to organic phase (1/1), volume ratio of emulsion phase to external phase (1/5) and stirring speed (300 rpm)) were also influential on improving the stability (about 0.2% breakage) and on achieving the most stable emulsion. The membrane with the highest stability was employed to extract acridine orange with various concentrations (10, 20 and 40 ppm) from water. The emulsion liquid membrane prepared with n-octane as the best solvent almost removed 99.5% of acridine orange from water. Also, the prepared liquid membrane eliminated completely (100%) other cationic dyes (methylene blue, methyl violet and crystal violet) from water demonstrating the efficacy of prepared emulsion liquid membrane in treatment of dye polluted waters.

• ETRI Journal
• /
• 제27권5호
• /
• pp.585-594
• /
• 2005

A small electronic nose (E-Nose) system has been developed using an 8-channel vapor detection array and personal digital assistant (PDA). The sensor array chip, integrated on a single microheater-embedded polyimide substrate, was made of carbon black-polymer composites with different kinds of polymers and plasticizers. We have successfully classified various volatile organic compounds such as methanol, ethanol, i-propanol, benzene, toluene, n-hexane, n-heptane, and c-hexane with the aid of the sensor array chip, and have evaluated the resolution factors among them, quantitatively. To achieve a PDA-based E-Nose system, we have also elaborated small sensor-interrogating circuits, simple vapor delivery components, and data acquisition and processing programs. As preliminary results show, the miniaturized E-Nose system has demonstrated the identification of essential oils extracted from mint, lavender, and eucalyptus plants.

• Transactions of the Korean Society of Automotive Engineers
• /
• 제9권4호
• /
• pp.44-49
• /
• 2001

Reduced chemical kinetics mechanism has been derived, which can be applicable for autoignition model of hydrocarbon fuels, and contains 23 reactions and 18 species. The present model is validated with the experimental data, where the ignition delays of several hydrocarbon fuels, such as n-heptane, i-octane, n-decane and DME(dimethylether) are measured as equivalence ratios are varied. Especially, the effects of different fuels on ignition delays can be explained by changing the rate constants of three reactions among the present model. As a result, the proposed model can be applicable to two stage ignition model of Diesel combustion.

• Journal of the Korean Applied Science and Technology
• /
• 제31권1호
• /
• pp.151-158
• /
• 2014

Asphaltenes are generally defined by their solubility when a light alkane, such as n-heptane or n-pentane, is mixed with crude oils or oil sand bitumen. However, this definition is nowadays not enough to understand their behaviors during oil recovery, transport, storage, and even refinery operation. Interestingly, the researches regarding asphaltenes have been vastly presented within last decade. This is because the production of heavy oils is becoming larger and asphaltenes are known to play an important role in the property changes of heavy oils. In this paper, the researches regarding molecular weight, aggregation behavior of asphaltenes are introduced and discussed. It is expected that analytical studies will be appeared continuously in the form of global collaboration in order to describe asphaltene molecules as close as possible based on their origin.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
• /
• pp.209-211
• /
• 2015

Evaporation characteristics of a single droplet of carbon nanofluids were investigated in a rapid compression machine(RCM). n-Heptane and carbon black N990 were used to synthesize the carbon nanofluids. RCM is an experimental set-up to simulate a single compression stroke of reciprocating engine. Temperature and pressure in a reaction chamber were measured during the compression stroke. After the piston reaches top dead center(TDC), temperature and pressure decreased due to the heat loss at wall. In that process, a single droplet of carbon nanofluids underwent unsteady condition. A single droplet was put at the center of reaction chamber. Thermocouple whose tip is $50{\mu}m$ was used not only to measure transient bulk temperature, but also to suspend the droplet. The picture of single droplet was taken using high speed camera with a frame rate of 500 fps. From those pictures, the droplet diameter was measured by visual basic program.