• Fire Science and Engineering
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• v.25 no.2
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• pp.126-131
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• 2011

This study is intended to understand mass loss rate and air entrainment rate of the whirl fire by height of fire source. Liquid fuels were methanol and n-Heptane which are used in many studies of whirl fire. Size of vessel was 100 mm ${\times}$ 100 mm ${\times}$ 50 mm and the vessel was made by stainless steel. When height of fire source changed from 0 cm to 30 cm, air entrainment rate showed the fastest in case of 0 cm. And in the same height of fire source, average and maximum air entrainment rate showed the fastest in 30 cm of anemometer. From the results of whirl fire for methanol and n-Heptane, mass loss rate and air entrainment rate of n-Heptane was found to faster 1.33 to 1.58 times and 4.38 to 5.44 times compared with methanol, respectively. Consequently, mass loss rate and air entrainment rate in whirl fire was able to identified decrease as height of fire source increases and the higher the heating value, increases the that's value.

• Elastomers and Composites
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• v.38 no.1
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• pp.51-56
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• 2003

Cloud-point and bubble-point data to $170^{\circ}C$ and 50 bar are presented for four different solvents, normal pentane. n-hexane, n-heptane, and n-octane with poly(ethylene-co-42 wt% octene) ($PEO_{42}$) copolymer. The pressure-concentration isotherms measured for $PEO_{42}$ - normal pentane have maximums at around 5 wt% of the copolymer concentrations in the solution. $PEO_{42}$- normal pentane system exhibits LCST-type phase behavior at temperatures greater than $130^{\circ}C$. Below $120^{\circ}C$, bubble-point type transitions are observed. However, the binary mixtures for $PEO_{42}$ in n-hexane, n-heptane, and n-octane have only bubble-point type transitions at the pressure-temperature region investigated in this study. The single-phase region of PEO - alkane mixtures increases with the molecular size of alkane solvent due to the increasing dispersion interactions between PEO and the alkane.

• Journal of the Korean Applied Science and Technology
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• v.13 no.3
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• pp.95-103
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• 1996

In the separation of toluene/n-heptane mixture by the emulsion type liquid membrane in an batch system, the effect of surfactant on the separation factor and membrane stability was studied over the surfactant concentration ranging form 0.1 to 1.5wt％ at the contact time of 5 and 10 minutes. and the settling time of 5 and 10 minutes. The surfactant used was sodium lauryl sulfate. The separation factor reached its maximum value at the surfactant concentration of 0.5wt％ for surfantant. It was found that the percentage of membrane breakup reached its minimum values and the separation factor showed its maximum value at the surfactant concentration of 0.5wt%. which confirmed that efficient separation could be effect when emulsion liquid membrane was stable because of low membrane breakup.

• Journal of the Korean Applied Science and Technology
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• v.16 no.1
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• pp.95-103
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• 1999

In the separation of toluene/n-heptane mixture by the emulsion type liquid membrane in a batch system, the effect of surfactants on the separation factor and membrane stability were studied over the surfactant concentration ranging from 0.1 to 1.5 wt% at the contact time of 5 and 10 minutes and the settling time 5 and 10 minutes. The surfactants used were triethanol amine lauryl sulfate. The separation factor reached its maximum value at the surfactant concentration of 0.5 wt%. It was found that the percentage of membrane breakup reached its minium values and the separation factor showed its maximum value at the surfactant concentration of 0.5 wt%, which confirmed that efficient separation could be effect when emulsion liquid membrane were stable because of low membrane break up.

• Applied Chemistry for Engineering
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• v.22 no.4
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• pp.390-394
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• 2011

Vapor liquid equilibria were measured for the binary systems of ditetrahydrofurfurylpropane (DTHFP) and some solvents such as cyclohexane, n-heptane, tetrahydrofuran, and water. Binary vapor liquid equilibria were measured for the diluted concentration range of DTHFP. NRTL model was used to analyze the measured data. With the experimental data, binary interaction parameters of the NRTL model were regressed.

• Korean Chemical Engineering Research
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• v.46 no.2
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• pp.356-368
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• 2008

The effects of cosurfactant on silica nanoparticles were investigated in systems containing surfactant, oil and aqueous ammonia solution where nanoparticles were prepared using a single phase water-in-oil (W/O) microemulsion. For the same oil phase, a single phase region was dependent on the interaction between surfactant and oil. For the cyclohexane system, NP-5 surfactant showed a wider single phase region than NP-4. The addition of n-propanol as a cosurfactant resulted in an increase or a decrease of a single phase W/O microemulsion region depending on the continuous oil phase. For both cyclohexane and isooctane systems, the addition of n-propanol resulted in a decrease in the single phase region. On the other hand, for n-heptane system, the addition of n-propanol expanded a single phase W/O microemulsion region. Silica nanoparticles prepared within a single phase region showed that relatively large number of particles of irregular shape were obtained with the addition of n-propanol to NP surfactant system. The addition of n-propanol to LA-5 surfactant and n-heptane system produced a decrease in average particle size and an increase in the number of particles formed due to a decrease in the intermicellar exchange rate among microemulsion droplets.

• Journal of ILASS-Korea
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• v.4 no.1
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• pp.27-33
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• 1999

An experimental study has been conducted to clarify the effect of vapor on droplet evaporation. Droplets of water, ethanol, n-hexadecane and n-heptane were exposed in air stream. Temperature, pressure, and flow velocity in the ambient air are 470K, 1 atm, and 2m/s, respectively. Measurements are carried out for the wide range of water vapor concentration$(0%\sim40%)$. To obtain the time histories of droplet diameter, suspended droplet in hot and humid air stream was synchronized with a back flash light, and enlarged droplet images were taken on a CCD camera. With the vapor concentration increasing, the evaporation rate constant of water droplet decrease slightly and the droplet of ethanol and n-heptane increase actively. The evaporation rate constant of n-hexadecane which has higher boiling point than water increases within around 30% of the concentration.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.1
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• pp.23-37
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• 2017

Objectives : This study was conducted to evaluate the level of exposure to volatile organic compounds (VOCs) among workers handling rust preventive oils. Methods : A total of 30 bulk samples and 54 personal air samples were collected using diffusive samplers at 22 workplaces handling rust preventive oils in Daegu and Gyongsangbuk-do Province from March to October 2013. We also investigated detailed information on the related work conditions, such as kinds of products, handling methods, local exhaustive ventilation systems, and the status of the wearing personal protective equipment. All bulk samples and air samples were analyzed using gas chromatography mass spectrometry (GC-MS) to identify components to which workers potentially were exposed. Quantitative airborne concentrations of VOCs were confirmed using gas chromatography with flame ionized detectors. Results : In terms of qualitative analyses for the 30 bulk samples, we found carcinogenic, mutagenic and reproductive toxic(CMR) substances such as butane(carcinogenic Group 1A, mutagenic Group 1B), butoxy ethanol(carcinogenic Group 2), cumene (carcinogenic Group 2), ethyl benzene(carcinogenic Group 2), methyl isobutyl ketone(carcinogenic Group 2) and toluene (reproductive toxic, Group 2). As a result of full-shift based personal air samples, eight substances such as n-hexane, n-heptane, octane, nonane, decane, toluene, ethyl benzene and xylene were detected. Among them, n-hexane and n-heptane were detected in all of 54 air samples with $13.13mg/m^3$ and $8.61mg/m^3$ of maximum concentration, respectively. The level of airborne concentration from all of samples were bellow the occupational exposure limit in Korea. Conclusions : Based on the results of this study, workers handling rust preventive oils could be exposed to CMR substances contained in rust preventive oils and n-hexane and n-heptane were found as the most frequent sources of VOC exposure.

• Journal of Nutrition and Health
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• v.15 no.1
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• pp.9-14
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• 1982

The present paper describes a colorimetric method of determining the free and total unsaturated fatty acids in animal tissues. The procedure is based in three steps on the following principles : First step is that the tissue homogenates are extracted in chilled acetone in order to eliminate the interfering substance, such as phospholipids, sulfatides and proteins. At next step, after centrifugation acetone layer is decanted and evaporated to dryness. Then the extract is shaken with heptane to solve in the solvent. That the characteristic nature of copper salts of unsaturated fatty acids are freely soluble in heptane and those of saturated acids are not is the bases of separating one from another. Thus unsaturated fatty acids can be isolated in heptane as their salts from saturated acids and other lipid mixture by shaking with copper reagent. Finally the yellowish brown color developed by adding color reagent (0.2% sodium diethyldithiocarbamate in n-butanol solution) which reacts with the copper salts of the acids and produces the color is measured colorimetrically.

• Journal of the Korean Society of Safety
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• v.27 no.3
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• pp.71-76
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• 2012

The coflow velocity effect on the minimum extinguishing concentration(MEC) was investigated experimentally in heptane cup-burner flames. Various inert gases($N_2$, Ar, $CO_2$, He) were added into the oxidizer to find the critical concentration and the effectiveness of the agents on flame extinction. The experimental results showed that the MECs were increased with increasing coflow velocity for most inert gases except helium, but the higher coflow velocity induced the lower burning rates of heptane. This indicated that the increase of coflow velocity resulted in the decrease of fuel velocity evaporated from fuel surface, and hence the stain rate on the reaction zone was also decreased. In the case of helium as a additive, the extinguishing concentration was independent of the coflow velocity because the heat conductivity was ten times larger than the other inert gases and flow effect by a strain rate might be compensated for heat loss to the surroundings.