• Journal of the Korea Furniture Society
• /
• v.28 no.3
• /
• pp.248-258
• /
• 2017

A study was carried out to observe the 1% aqueous safranine solution flow speed in longitudinal and radial directions of softwood Thuja orientalis L., diffuse-porous wood Gmelina arborea Roxb., and ring-porous wood Phellodendron amurense Rupr., Longitudinal flow was considered from bottom to top while the radial flow was considered from bark to pith directions. In radial direction, ray cells and in longitudinal direction tracheids, vessel and wood fiber were considered for the measurement of liquid penetration speed at less than 12% moisture contents(MC). The variation of penetration speed for different species was observed and the reasons behind for this variation were explored. The highest radial penetration depth was found in ray parenchyma of T. orientalis but the lowest one was found in ray parenchyma of P. amurense. The average liquid penetration depth in longitudinal trachied of T. orientalis was found the highest among all the other cells. The penetration depth in fiber of G. arborea was found the lowest among the other longitudinal cells. It was found that cell dimension and also meniscus angle of safranine solution with cell walls were the prime factors for the variation of liquid flow speed in wood. Vessel was found to facilitate prime role in longitudinal penetration for hardwood species. The penetration depth in vessel of G. arborea was found highest among all vessels. Anatomical features like ray parenchyma cell length and diameter, end-wall pits number were found also responsible fluid flow differences. Initially liquid penetration speed was high and the nit gradually decreased in an uneven rate. Liquid flow was captured via video and the penetration depths in those cells were measured. It was found that even in presence of abundant rays in hardwood species, penetration depth of liquid in radial direction of softwood species was found high. Herein the ray length, lumen area, end wall pit diameter determined the radial permeability. On the other hand, vessel and fiber structure affected the longitudinal flow of liquids. Following a go-stop-go cycle, the penetration speed of a liquid decreased over time.

• Resources Recycling
• /
• v.19 no.6
• /
• pp.77-85
• /
• 2010

This study was carried out to develop a process flow sheet for recovering valuables (gold and high purity silica) from the gold mine tailings containing 1.7 g/ton of gold and 79.48 wt.% $SiO_2$. Float-sink tests using heavy liquids was conducted to explore the possibility of recovering gold by gravity separation. Hydrocyclone, froth flotation, and triboelectrostatic separatoin tests were conducted to recover high purity silica from the gold mine tailings. The results of float-sink tests showed that particles containing 5.58 g/ton of gold could be obtained at 2.72 specific gravity, but with very low yields around 3%. Meanwhile, all tests with hydrocyclone, froth flotation, and triboelectrostatic separation showed that high purity silica with $SiO_2$ content over 90% could be obtained. The purity could be improved further up to about 94% by employing several recleaning steps in the froth flotation and triboelectrostatic process.

• Polymer(Korea)
• /
• v.24 no.3
• /
• pp.326-332
• /
• 2000

The effects of sizing agent on the final mechanical properties of the glass fiber/unsaturated polyester composites were investigated by contact angle measurements at room temperature. In this work, glass fibers were coated by poly(vinyl alcohol), polyester, and epoxy type sizing agent and each property was compared. Contact angles of the sized glass fiber were measured by the wicking method based on Washburn equation using deionized water and diiodomethane as testing liquids. As an experimental result, the surface free energy calculated from contact angle showed the highest value in case of the glass fiber coated by epoxy sizing agent. From measurements of interlaminar shear strength (ILSS) and fracture toughness ( $K_{IC}$ ) of the composites, it was found that the sizing treatment on fibers could improve the fiber/matrix interfacial adhesion, resulting in growing the final mechanical properties. This was due to the enhanced surface free energy of glass fibers in a composite system.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.176.2-176.2
• /
• 2013

Property of optical diagnostics for pulse-discharged plasma in liquid and its biological applications to proteins are investigated by making use of high voltage Marx generator. The Marx generator has been consisted of 5 stages, where each charging capacitor is 0.5 ${\mu}F$, to generate a high voltage pulse with rising time of $1{\mu}s$. We have applied an input voltage of 6 kV to the each capacitor of 0.5 ${\mu}F$. High voltage pulsed plasma has been generated inside a polycarbonate tube by a single-shot operation, where the breakdown voltage is measured to be 7 kV, current of 1.2 kA, and pulse width of ~ 1 ${\mu}s$ between the two electrodes of anode-cathode whose material is made of tungsten pin, which are immersed into the liquids. We have investigated the emitted hydrogen lines for optical diagnostics of high voltage pulsed plasma. The emission line of 656.3 nm from $H-{\alpha}$ and 486.1 nm from $H-{\beta}$ have been measured by a monochromator. If we assumed that the focused plasma regions satisfy the local thermodynamic equilibrium conditions, the electron temperature and density of the high voltage pulsed plasma in liquid could be obtained by the Stark broadening of optical emission spectroscopy. For the investigation of the influence of pulsed plasma on biological proteins, we have exposed it onto the proteins such as hemoglobin and myoglobin. The structural changes in these proteins and their analysis have also been obtained by circular dichroism (CD) and ultraviolet (UV) visible spectroscopy.

• Applied Chemistry for Engineering
• /
• v.27 no.2
• /
• pp.153-157
• /
• 2016

In this study, three different metal-containing ionic liquid catalysts were prepared by metal insertion and characterized by various physicochemical analytic methods. The catalytic performance of the metal containing ionic liquids in the cycloaddition of $CO_2$ with propylene oxide (PO) to produce propylene carbonate (PC) was investigated under the solvent free condition. The order of approximate rate constants ($K_{app}$) for the metal containing ionic liquid catalysts was $(MeIm)_2ZnCl_2$, > $(MeIm)_2FeCl_2$ > $(MeIm)_2CuCl_2$. These results are in accord with the experimentally obtained activity order of the different metal containing ionic liquid catalysts.

• Fire Science and Engineering
• /
• v.31 no.5
• /
• pp.1-6
• /
• 2017

The fire and explosion properties of combustible materials are necessary for the safe handling, storage, transportation and disposal. Typical combustion characteristics for process safety include auto ignition temperature(AIT). The AIT is an important index for the safe handling of combustible liquids. The AIT is the lowest temperature at which the material will spontaneously ignite. In this study, the AITs and ignition delay times of n-pentanol and p-xylene mixture were measured by using ASTM E659 apparatus. The AITs of n-pentanol and p-xylene which constituted binary system were $285^{\circ}C$ and $557^{\circ}C$, respectively. The experimental AITs and ignition delay times of n-pentanol and p-xylene mixture were a good agreement with the calculated AITs and ignition delay times by the proposed equations with a few A.A.D. (average absolute deviation). Therefore, it is possible to estimate the AITs and ignition delay times in other compositions of n-pentanol and p-xylene mixture by using the predictive equations which presented in this study.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.9 no.1
• /
• pp.91-97
• /
• 2009

Hazardous material (HazMat) is the material or substance that poses an unreasonable risk to human safety and health, and to property when transported in gases, solids, and liquids of all sizes. When HazMats are improperly released, they have potential to harm humans, property, or the environment to be considered hazardous, resulting in human-caused disasters. As the Korean economy has advanced, the use of HazMats has increased. And, the total number and the impacts of HazMat incidents have grown up. It increases the risk of HazMat incidents. When many goods of HazMats are transported from supply points to demand places, it is important to know what the types and characteristics of HazMat incidents are in terms of disaster management. The objectives of this research are: (1) to investigate types and characteristics of HazMats that generate HazMat incidents in Korea, and (2) to analyze time-series trends of HazMat incidents in terms of facilities and/or transportation. Statistical analysis methods including frequency analysis or analysis of category data are applied to examine the significance of difference in HazMat incidents.

• Journal of the Korean Applied Science and Technology
• /
• v.34 no.4
• /
• pp.1112-1120
• /
• 2017

Petroleum products are composed of various types of hydrocarbon compounds. Like other types of liquids, they presented the variation of density and volume according to temperature change. The method of measuring the density of petroleum products in a liquid phase is based on experimental data obtained mainly for each fractionally distilled petroleum product. In this study, the density and volume changes of kerosene and automotive diesel according to temperature change were measured and the property of change were analyzed. The conversion values were calculated using the density volume conversion table proposed by international standard ASTM. In addition, we analyzed the differences between the reference values and the measured values for the temperature changes specified in the domestic metering law.

• Current Optics and Photonics
• /
• v.3 no.5
• /
• pp.415-422
• /
• 2019

Retroreflection of vehicle headlights, as induced by spherical glass beads, is a key optical phenomenon that provides road-surface markings with greatly enhanced visibility, thus better securing a driver's safety in the nighttime as well as in unclear daytime. Retroreflectance of glass beads is a quite sensitive function of their refractive index, so that measurement of the refractive index of glass specifically in the shape of spherical beads needs to be performed within a reasonable uncertainty that is tolerable for road-marking applications. The Becke line method has been applied in assessing refractive index of such glass beads as e.g. an industrial standard in the Republic of Korea; however, the reference refractive-index liquids are not commercially available these days for refractive index greater than 1.80 due to the toxicity of the constituent materials. As such, high-refractive-index glass beads require an alternate method, and in this regard we propose a practically serviceable technique with uncertainty tantamount to that of the Becke line method: Based on comparison of calculated and measured retroreflectance values of commercial glass beads, we discover that their refractive index can be determined with reasonable precision via the retroreflectance measurement. Specifically, in this study the normalized retroreflectance originating from a single glass sphere is computed as a function of refractive index using the Fresnel equations, which is then validated as coinciding well with retroreflectance values measured from actual specimens, i.e. glass-bead aggregates. The uncertainties involved are delineated in connection with radius and imperfections of the glass beads.

• Journal of the Health Care and Life Science
• /
• v.9 no.1
• /
• pp.141-146
• /
• 2021

Determination of capsaicin, dihydrocapsaicin and nonivamide in pungent liquids of self-defense spray were studied. The nonivamide having almost same spicy taste with capsaicin have been containing a few amounts in natural products, it had called as synthetic capsaicin or PAVA, have used to flavorings for foodstuffs and incapacitating agents of riot controls. Nowadays, it has been occasionally found that the quality controls of a self-defense sprays were not properly due to flood of illegal self-defense sprays. Thus, the simple analytical method with gas chromatography is developed, it is identified whether the products which have contained synthetic capsaicin were marked like natural materials as well as the pungent ingredients in it obeyed with permissible concentration to human or not was investigated. Finally, the pungent components and amounts in some kinds of self-defense spray were investigated.