• Tribology and Lubricants
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• v.10 no.1
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• pp.78-88
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• 1994

For the study of chemical and mechanical properties of the synthetic and mineral oil added with two different Zn-DTPs, base and formulated oils were analyzed and compared. Kinematic viscosity and total acid number (TAN) were tested at high temperature for formulated oils. Also the oils added with different alkyl groups of Zn-DTP were tested for thermal stability and TAN changes. The 4-ball machine was used to test for the mechanical properties, such as the coefficient of friction and wear. The worn areas after sliding test were analyzed with microscope and EDX, too. From the study, mineral and synthetic oil have different effects according to the various added ratio of the primary and secondary alkyl groups of Zn-DTP. Also the temperature of test oil affected the anti-wear and friction property of the formulated oils. For synthetic oil, the primery alkyl group of Zn-DTP made better friction properties than that of secondary, while, for mineral oil, secondary alkyt group was better only at low temperature for mineral oil.

• Journal of the speleological society of Korea
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• no.8
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• pp.77-84
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• 1998

A large number of lava tubes in southwestern idaho contain some extremely impressive secondary mineral deposits. Gypsum and mirabilite can be found coating entire lava formation and in some cases entire rooms, thenardite and cristobolite can also be found throughout idaho's lava tubes, although in smaller individual concentrations. To a lesser degree iron and copper-based deposits have been found. On rare occasions and in very small quantities calcium carbonate deposits have been found.(omitted)

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.651-656
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• 2003

Durability of concrete is possibly related to externally-induced chemical attacks in addition to internally-induced deterioration. Externally-induced chemical attacks can be derived from various sources according to environmental conditions under which concrete structures are existing. The present study investigates the characteristic concrete deterioration and formation of secondary minerals by external chemical attacks under certain environmental condition. Petrographic microscope, SEM, EDAX, XRD analyses were conducted to identify secondary mineral formation and micro-structural analyses.

• Journal of the Mineralogical Society of Korea
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• v.10 no.1
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• pp.33-44
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• 1997

The reaction path of water-gneiss in 200m borehole at the Soorichi site of Yugu Myeon, Chungnam was simulated by the EQ3NR/EQ6 program. Mineral composition of borehole core and fracture-filling minerals, and chemical composition of groundwater was published by authors. In this study, chemical evolution of groundwater and formation of secondary minerals in water-gneiss system was modelled on the basis of published results. The surface water was used as a starting solution for reaction. Input parameters for modelling such as mineral assemblage and their volume percent, chemical composition of mineral phases, water/rock ratio reactive surface area, dissolution rates of mineral phases were determined by experimental measurement and model fit. EQ6 modelling of the reaction path in water-gneiss system has been carried out by a flow-centered flow through open system which can be considered as a suitable option for fracture flow of groundwater. The modelling results show that reaction time of 133 years is required to reach equilibrium state in water-gneiss system, and evolution of present groundwater will continue to pH 9.45 and higher na ion concentration. The secondary minerals formed from equeous phase are kaolinite, smectite, saponite, muscovite, mesolite, celadonite, microcline and calcite with uincreasing time. Modeling results are comparatively well fitted to pH and chemical composition of borehole groudwater, secondary minerals identified and tritium age of groundwater. The EQ6 modelling results are dependent on reliability of input parameters: water-rock ratio, effective reaction surface area and dissolution rates of mineral phases, which are difficult parameters to be measured.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.101-103
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• 2004

To investigate the evidence for the influence of sea water on Pohang geothermal groundwater, the chemical data for geothermal groundwaters from which are pumped during 48 hours and other hot groundwaters, another groundwater on the well for the purpose of agriculture, were considered. And to predict possible the secondary mineral which are easily to make the clogging, geochemical modeling was carried out using EQ3NR equilibrium solubility code. The results are that 1.4%～3.3%(bulk composition) of sea water were mixed with geothermal groundwater. From the well logging data, when the level of groundwater is drow down, the conductivity is increased in the geothermal groundwater, the existence of transition zone are recognized in the well. The predicted possible secondary minerals are Antigorite [Mg48Si24O85(OH)62], Chrysolite [Mg3Si2O5(OH)4] , Cristobalite, Dolomite, Talc, Tremolite. The recommended cooling temperature of best condition to minimize the production of secondary minerals is same as temperature of geothermal water pumped from the well.

• Journal of the speleological society of Korea
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• no.4
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• pp.33-39
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• 1996

Secondary mineral deposits of gypsum, mirabilite, thenardite, crisobolite have long been known and, in fact, are quite common in lava tubes of southwest Idaho. Until recently, calcium carbonate were found in a few tubes in very small amounts and were thought to be qu are. The recent ‘rediscovery’ of Helen's Hidden Hide - Away lava tube h significantly changed this thinking. The deposits in this lava tube are only quite extensive but extremely varied in structure. As this is a v recent discovery, only basic preliminary work will be presented in t paper. It is hoped this will stimulate intrest for further and more inte study of the lava tubes of southwestern Idaho.

• Journal of the speleological society of Korea
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• no.5
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• pp.70-78
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• 1997

Secondary mineral deposits of gypsum, mirabilite, thenardite, and cristpbolite have long been known and, in fact, are quite common in the lava deposits tubes of southwest idaho. Until recently, calcium carbonate were only found in a few tubes in very small amounts and were though to be quite rare. The recent ‘rediscovery’ of Henlen's Hidden Hide -A way lava tube has significantly changed this thinking. The deposits in the lava tube are not only quite extensive but extremely varied in structure. As this is a very recent discovery, only basic preliminary work will be presented in this paper. It is hoped this will stimulate interest for further and more intensive study of the lava tubes of southwestern idaho.

• Journal of the speleological society of Korea
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• no.8
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• pp.11-18
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• 1998

The mineral hydroxyapatite is very common species in secondary phosphates originating from guanos(HILL et at., 1997). Several mineralogical analyses of spelean hydroxyapatite exist(e.g., KASHIMA, 1968, 1979 ; MAKI et at., 1977 ; SUH et at., 1978 ; WANG, 1982 a, b), whereas detailedeochemical composition of secondary hydroxy apatites has not been reported in Japan.(omitted)

• Particle and aerosol research
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• v.15 no.4
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• pp.127-137
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• 2019

Recently, high electrochemical performance anode materials for lithium ion secondary batteries are of interest. Here, we present silicon-carbon-graphene (Si-C-GR) composites for high performance anode materials of lithium ion secondary battery (LIB). Aerosol process and heat-treatment were employed to prepare the Si-C-GR composites using a colloidal mixture of silicon, glucose, and graphene oxide precursor. The effects of the size of the silicon particles in Si-C-GR composites on the material properties including the morphology and crystal structure were investigated. Silicon particles ranged from 50 nm to 1 ㎛ in average diameter were employed while concentration of silicon, graphene oxide and glucose was fixed in the aerosol precursor. Morphology of as-fabricated Si-C-GR composites was generally the shape of a crumpled paper ball and the Si particles were well wrapped in carbon and graphene. The size range of composites was about from 2.2 to 2.9 ㎛. The composites including silicon particles larger than 200 nm in size exhibited higher performance as LIB anodes such as capacity and coulombic efficiency than silicon particles less than 100 nm, which were about 1500 mAh/g at 100 cycles in capacity and 99% in coulombic efficiency, respectively.

• Economic and Environmental Geology
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• v.48 no.6
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• pp.525-536
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• 2015

Trapiche project corresponds to the advanced exploration stage which is thought to be a part of various porphyry copper deposits occurring in the margin of Andahuyalas-Yauri metallogenic belt. This deposit is genetically related to the monzonitic porphyry intrusion and Oligocene breccia pipe. Mineralization consists of primary sulfides such as pyrite, chalcopyrite, bornite, and molybdenite and secondary sulfides such as chalcocite, covellite and digenite. It occurs malachite, tenorite and cuprite as copper oxide. As a result of lixiviation or enrichment process, mineralization shows untypical zonation structure. Breccia and porphyry areas characterize the vertical zonation patterns. In the northern area, lixiviation zone, secondary enrichment zone, transitional zone and primary mineralized zone are distributed in northern area. In the western area of deposit, oxidation zone and mixed zones are narrowly occurred. Inferred resources of deposit is estimated to be 920 Mt @ 0.41% Cu with the cut-off grade of 0.15%.