• Transactions of the Korean hydrogen and new energy society
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• v.19 no.4
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• pp.340-347
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• 2008

Dissolution process of serpentine in distilled water was systematically investigated for study on pre-treatment of serpentine which was a candidate material for carbon dioxide sequestration. The metallic ions(Ca, Si, Mg etc.) were dissolved in distilled water at ambient condition and their concentrations were changed with dissolution time. The precise evaluation of dissolution process for serpentine dissolved solvent was performed by ion conductivity and pH measurement. Serpentine dissolution in distilled water was evaluated as a stable pre-treatment process without changes of crystallographic structure and chemical structure changes.

• Journal of the Mineralogical Society of Korea
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• v.9 no.2
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• pp.102-112
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• 1996

The precious serpentine, referring to a rare and highly valuable gem variety of serpentine group minerals, is found to occur in serpentinite from Booyo Gren Jade Mine which is located in Oesan-myun, Booyo-gun of Chungchungnam-do. Geommological properties of the precious serpentine have been investigated by use of polarizing microscope, specific gravity balance, refractometer, hardness pencils, X-ray diffractometer, XRF, ICP-MS analyser, and infrared absorption spectroscope.The precious serpentine from Booyo is colored deep green with oily luster and semi-transparent. It is highly tough and Mohs's scale of hardness is measured to be 5-6. Specific gravity is determined to be 2.67, and a single refractive index ND=1.56 is observed by a spot method, using sodium light source. X-ray powder diffraction data is represented by the reflection lines at 7.40(100), 4.64(25), 3.68(68), 2.757(69), 2.530(49), 2.549(32), and 1.710(21${\AA}$), which compares very well with that of antigorite of serpentine group minerals. The major chemical compositions of the precious serpentine group minerals. The major chemical compositions of the precious serpentine are SiO2 42.49%, MgO 39.08%, Fe2O3 3.85%, and H2O 11.87%. Besides, trace elements such as Cr(2188), Ni(1110ppm), Co(58ppm), and Ta (108ppm) are relatively spectrum shows peaks at 3670, 1190, 1070, 980 and 610cm-1. Strong absorption at 3670cm-1 is due to OH stretching, and 1190, 1070 and 980cm-1 due to SiO stretching. The absorption 610cm-1 is formed by alteration of pre-existing ultramafic rock, namely peridotite, with an introduction of fluid with very little content of CO2, under 400$^{\circ}C$ environment. Magnetite inclusions, finely disseminated in the precious serpentine, may be a result of Fe precipitation, during serpentinization of olivine-bearing country rock.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.1
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• pp.35-40
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• 2013

Objectives: Asbestos contents of crushed serpentine rocks and airborne fiber concentrations of workers were determined at two serpentine quarries and a steel mill. Methods: Bulk samples of uncrushed and crushed serpentine rocks were collected and analyzed by PLM and TEM. Airborne asbestos samples were collected from the breathing zone of workers and the vicinity of working area and analyzed by PCM and TEM. Results: Chrysotile was identified with antigorite, lizardite and non-asbestiform actinolite in bulk samples. The arithmetic means of chrysotile contents in crushed serpentines were 0.11, 0.01, 0.42%(W/W) by quarry A, quarry B and a steel mill, respectively. The asbestos concentrations of all personal samples were less than 0.1 f/cc which is the permissible exposure limit of workers in Korea. The arithmetic means of airborne asbestos concentrations were 0.017 f/cc and 0.009 f/cc in personal samples collected from two serpentine quarries. The asbestos concentrations of all personal samples collected from a steel mill were less than LODs by PCM analysis but asbestos was detected in area samples by TEM. By the job tasks of serpentine quarries, crusher/separator operation generated the highest exposure to airborne asbestos. Conclusions: Although chrysotile contents in crushed serpentines of quarries were less the permissible level, the highest exposure of workers in serpentine quarries reached up to 76% of the permissible level of airborne asbestos. There were also possibilities of occupational exposure to airborne asbestos in a steel mill. The present exposure study should encourage further survey and occupational control of quarries producing serpentine or other types of asbestos-bearing rocks.

• Applied Chemistry for Engineering
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• v.21 no.1
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• pp.24-28
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• 2010

Since the reaction of mineral fixation proceeds with a very slow rate, the pretreatment method to increases the rate of carbonation reaction should be required. To increase the reactivity of serpentine with $CO_{2}$, two pretreatment methods are performed in this study. The heat treatment is done at $630^{\circ}C$. A heat-treated serpentine shows that the strength of -OH has a lower peak in FT-IR spectrum. Chemical pretreatment is the method of leaching of magnesium from serpentine using sulfuric acid at $75^{\circ}C$ for 1 h. Because the protonation of the oxygen atoms polarizes and weakens the Mg-O-Si bond, the removal of magnesium atoms from the crystal lattice was facilitated. After performing the pre-treatment of serpentine, $CO_{2}$ fixation experiments are performed with treated serpentine in the batch reactor. Heat-treated serpentine is converted into 43% magnesite conversion, whereas untreated serpentine has 27% of magnesite conversion. Although the results of the heat-pretreatment are encouraging, this method is prohibited due to excessive energy consumption. Furthermore chemical pretreatment serpentine routes have been proposed in an effort to avoid the cost prohibitive heat pretreatment, in which the carbonation reaction was conducted at 45 atm and $25^{\circ}C$. Chemical-treated serpentine, in particularly is corresponded to a conversion of 42% of magnesite compared to 24% for the un-treated serpentine.

• Korean Journal of Environment and Ecology
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• v.32 no.6
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• pp.676-685
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• 2018

This study is to compare carbon budget between serpentine sites and non-serpentine sites dominated by Pinus densiflora forest in the Andong serpentine area where has high values of magnesium and low values of calcium, and are usually deficient in nitrogen and phosphorus, but rich in heavy metals such as nickel, chrome, cobalt, etc. and to measure soil $CO_2$ efflux and environmental factors between January 2017 and December 2017. Soil $CO_2$ efflux was measured with LI-6400 once a month; the soil temperature at 10 cm depth, air temperature, soil moisture contents, and solar radiation were measured in continuum. Soil $CO_2$ efflux in the serpentine area and non-serpentine were $151.71{\pm}75.09g\;CO_2{\cdot}m^{-2}month^{-1}$(42.48 ~ 262.61 g $CO_2{\cdot}m^{-2}month^{-1}$) and $165.09{\pm}118.96g\;CO_2{\cdot}m^{-2}month^{-1}$(20.94 ~ 449.24 g $CO_2{\cdot}m^{-2}month^{-1}$), respectively. Carbon storage in the serpentine area and non-serpentine area were 91.90, $222.85ton{\cdot}ha^{-1}$, respectively. Carbon absorption in the serpentine area and non-serpentine area were 7.99, $17.41ton{\cdot}ha^{-1}yr^{-1}$, respectively. Carbon budget in the serpentine area and non-serpentine area were absorbs 5.3, $14.49ton{\cdot}Cha^{-1}yr^{-1}$, respectively.

• Journal of the Mineralogical Society of Korea
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• v.25 no.1
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• pp.9-21
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• 2012

Six serpentine mines are found in South Korea. We investigated occurrence, characteristics and origin of constituent minerals of Bibong serpentine mine in Chungcheongnam-do. We also analyzed the properties of serpentine minerals using XRD, XRF, SEM/EDS, FT-IR, EPMA and polarized microscope. The serpentinite of Bibong mine occurs as intruded body within the Precambrian metasedimentary rocks. Various minerals such as serpentine, forsterite, pyroxene, tremolite, magnetite, chlorite, mica, talc and dolomite are occurre. Five distinctive mineral assemblage types are observed in the serpentinite: (A) serpentine-forsterite, (B) serpentine, (C) serpentine-chlorite (vermiculite), (D) serpentine-tremolite, (E) tremolite-chlorite. Lizardite and antigorite are mainly occurred as serpentine minerals and chrysotile is partly included. From the study of mineral compositions and occurrence of serpentinite body, serpentine formed by hydrothermal alteration of ultramafic rock consisting mainly of forsterite, and altered minerals such as chlorite and tremolite subsequently formed by secondary hydrothermal alteration.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.756-759
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• 2004

We present a piezoelectric actuator using stiffness control and stroke amplification mechanism in order to make large lateral displacement. In this work, we suggest stiffness control approach that generates lateral displacement by increasing the vertical stiffness and reducing the lateral stiffness using additional structure. In addition, an additional structure of a serpentine spring amplifies the lateral displacement like leverage structure. The suggested lateral PZT actuator (bellows actuator) consists of serpentine spring and PZT/electrode layer which is located at the edge of the serpentine spring. The edge of the serpentine spring prevents the vertical motion of PZT layer, while the other edge of the serpentine spring makes stroke amplification like leverage structure. We have determined dimensions of the bellows actuator using ANSYS simulation. Length, width and thickness of PZT layer are 135$\mu$m, 20$\mu$m and 0.4$\mu$m, respectively. Dimensions of the silicon serpentine spring are thickness of 25$\mu$m, length of 300$\mu$m, and width of 5$\mu$m. The bellows actuator has been fabricated by SOI wafer with 25$\mu$m-top silicon and 1$\mu$m-buried oxide layer. The bellows actuator shows the maximum 3.93$\pm$0.2$\mu$m lateral displacement at 16V with 1Hz sinusoidal voltage input. In the frequency response test, the fabricated bellows actuator showed consistent displacement from 1Hz to 1kHz at 10V. From experimental study, we found the bellows actuator using thin film PZT and silicon serpentine spring generated mainly laterally displacement not vertical displacement at 16V, and serpentine spring played role of stroke amplification.

• Advances in nano research
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• v.12 no.2
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• pp.151-165
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• 2022

Micro-scale serpentine structure fibers are widely used as flexible sensor in the manufacturing of micro-nano flexible electronic devices because of their outstanding non-linear mechanical properties and organizational flexibility. The use of melt electrowriting (MEW) technology, combined with the axial bending effect of the Taylor cone jet in the process, can achieve the micro-scale serpentine structure fibers. Due to the interference of the process parameters, it is still challenging to achieve the precise deposition of micro-scale and high-consistency serpentine structure fibers. In this paper, the micro-scale serpentine structure fiber is produced by MEW combined with axial bending effect. Based on the controlled deposition of MEW, applied voltage, collector speed, nozzle height and nozzle diameter are adjusted to achieve the precise deposition of micro-scale serpentine structure fibers with different morphologies in a single motion dimension. Finally, the influence mechanism of the above four parameters on the precise deposition of micro-scale serpentine fibers is explored.

• The Korean Journal of Ecology
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• v.20 no.5
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• pp.385-391
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• 1997

To investigate the degrees of toxification in the serpentine areas, serpentinites and adjacent metamorphic rocks and soils from the serpentinite, metamorphic area and transitional area(mixed soil) between serpentinite and metamorphic rocks are collected from the Hongseong-Gun, Chungnam. A plant, Geochemically, the serpentinites are high in the nickel, chromium and cobalt content whereas the metamorphic rocks show high zinc, scandium, molybdenum and iron contents. The serpentine soils are high in the nickel, chromium and cobalt contents whereas the non-serpentine soils show high zinc and iron contents. Heavy metal contents in the G. oldhamiana are high in the serpentine soil relative to the mixed soil. Ratio of the iron to nickel contents for the G. oldhamiana are low in the serpentine soil(49) relative to the mixed soil(216). Of the G. oldhamiana, most of the heavy metal contents except zinc and molybdenum are high in the root relative to the aboveground vegetation. Comparing with rocks, the G. oldhamiana is low in the all of heavy metal contents relative to the serpentinite. Uptake of zinc by the G. oldhamiana is high in the serpentinites and metamorphic rocks whereas uptake of scandium and iron by the G. oldhamiana is very high in the serpentinite area.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.4
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• pp.288-297
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• 2009

A serpentine channel geometry often used in a fuel cell has a strong pressure gradient between adjacent channels in specific regions. The pressure gradient helps some amount of reactant gas penetrate through a gas diffusion layer(GDL). As a result, the overall serpentine flow structure is slightly different from the intention of a designer. The purpose of this paper is to examine the effect of serpentine flow structure on current density distribution. By using a commercial code, STAR-CD, a numerical simulation is performed to analyze the fuel cell with high aspect ratio of active area. To increase the accuracy of the numerical simulation, GDL permeabilities are measured with various compressive forces. Three-dimensional flow field and current density distribution are calculated. For the verification of the numerical simulation results, water condensation process in the cathode channel is observed through a transparent bipolar plate. The result of this study shows that the region of relatively low current density corresponds that of dropwise condensation in cathode channels.