• Title/Summary/Keyword: water environments

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Ore minerals and Genetic Environments from the Baekun Gold-silver Deposit, Republic of Korea (백운 금-은광상에서 산출되는 광석광물과 생성환경)

  • Yoo, Bong-Chul;Lee, Hyun-Koo;Kim, Ki-Jung
    • Economic and Environmental Geology
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    • v.39 no.1 s.176
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    • pp.9-25
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    • 2006
  • Baekun gold-silver deposit is an epithermal quartz vein that is filling the fault zone within Triassic or Jurassic foliated granodiorite. Mineralization is associated with fault-breccia zones and can be divided into two stages. Stage I which can be subdivided early and late depositional stages is main ore mineralization and stage II is barren. Early stage I is associated with wallrock alteration and the formation of sulfides such as arsenopyrite, pyrite, pyrrhotite, sphalerite, marcasite, chalcopyrite, stannite, galena. Late stage I is characterized by Au-Ag mineralization such as electrum, Ag-bearing tetrahedrite, stephanite, boulangerite, pyrargrite, argentite, schirmerite, native silver, Ag-Te-Sn-S system, Ag-Cu-S system, pyrite, chalcopyrite and galena. Fluid inclusion data indicate that homogenization temperatures and salinity of stage I range from $171.6^{\circ}C\;to\;360.8^{\circ}C\;and\;from\;0.5\;to\;10.2\;wt.\%\;eq.$ NaCl, respectively. It suggest that ore forming fluids were cooled and diluted with the mixing of meteoric water. Also, Temperature (early stage I: $236\~>380^{\circ}C,\;$ late stage $I: <197\~272^{\circ}C$) and sulfur fugacity (early stage $I:\;10^{-7.8}$ a atm., late stage I: $10^{-14.2}\~10^{-l6}atm$.) deduced mineral assemblages from stage 1 decrease with paragenetic sequence. Sulfur ($2.4\~6.1\%_{\circ}$(early stage $I=3.4\~5.3\%_{\circ},\;late\;stage\;I=2.4\~6.1\%_{\circ}$)), oxygen ($4.5\~8.8\%_{\circ}$(quartz: early stage $I=6.3\~8.8\%_{\circ}$, late stage $I=4.5\~5.6\%_{\circ}$)), hydrogen ($-96\~-70\%_{\circ}$ (quartz: early stage $I=-96\~-70\%_{\circ},\;late\;stage\;f=-78\~-74\%_{\circ},\;calcite:\;late\;stage\;I=-87\~-76\%_{\circ}$)) and carbon ($-6.8\~-4.6\%_{\circ}$ (calcite: late stage I)) isotope compositions indicated that hydrothermal fluids may be magmaticorigin with some degree of mixing of another meteoric water for paragenetic time.

Effect of Soil Environment on Diversity and Population of Aerobic Soil Bacteria from Baekdudaegan Mountain Forests in Gyeongsangbuk-do, Korea (경상북도 산림지역의 토양 환경이 호기성 토양 세균의 다양성과 밀도에 미치는 영향)

  • Park, Chul Yeong;Lee, Sun Keun;Kim, Ji Hong;Lee, Sang Yong;Lee, Jong Kyu
    • Journal of Korean Society of Forest Science
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    • v.101 no.3
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    • pp.501-508
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    • 2012
  • This study was carried out to compare species diversity of soil bacteria from Baekdudaegan mountain forests (Bonghwa-gun, Mungyeong-si and Sangju-si) in Gyeongsangbuk-do and to analyze the effects of soil environments on diversity and population of soil bacteria. Soil bacteria were isolated from soil samples by streak plate method, and identified by DNA extaction and 16S rDNA sequence analyses. The population of soil bacteria from the soil samples of Bonghwa-gun was the highest with $5.1{\times}10^5cfu/g$, and followed by those from Mungyeong-si and Sangju-si with $1.9{\times}10^5cfu/g$ and $1.1{\times}10^5cfu/g$, respectively. The population of soil bacteria from surface layer soil was the highest, and then gradually decreased according to soil depth. The increase in population of soil bacteria from soil samples of different sites was correlated with the increase of the altitude of soil sampling site, depth of A horizon, liquid phase among three phases of soil, water content and bulk density of soil. Two hundreds and sixty eight bacterial colonies from Bonghwa-gun were classified into 10 species, 8 genera. One hundred and thirty four bacterial colonies from Mungyeong-si were classified into 15 species, 9 genera. Forty four bacterial colonies from Sangju-si were classified into 5 species, 2 genera. The dominant species (occupancy rate) from Bonghwa-gun and Mungyeong-si were Bacillus weihenstephanensis (36% and 40%, respectively), and Sangju-si was Bacillus cereus (39%). The relationships between soil environment and community structure of soil bacteria were analyzed statistically by using ecological indices. The diversity, evenness and dominance indices of soil bacteria were 6.30, 2.04 and 0.59 in Bonghwa-gun, 9.09, 2.94 and 0.51 in Mungyeong-si, and 4.55, 2.34 and 0.71 in Sangju-si, respectively. The diversity and evenness indices were increased by the increase of water content, drainage condition and gravel content of soil, while the dominance index was decreased.

Classification System of Wetland Ecosystem and Its Application (습지생태계 분류체계의 검토 및 적용방안 연구)

  • Chun, Seung Hoon;Lee, Byung Hee;Lee, Sang Don;Lee, Yong Tae
    • Journal of Wetlands Research
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    • v.6 no.3
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    • pp.55-70
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    • 2004
  • The wetland ecosystem is a complex products of various erosion force, accumulation as water flows, hydrogeomorphic units, seasonal changes, the amount of rainfalls, and other essential element. There is no single, correct, ecologically sound definition for wetlands because of the diversity of wetlands and the demarcation between dry and wet environments occurs along a continuum, but wetland plays various ecosystem functions. Despite comprehensive integration through classification and impact factors there is still lacking in systematic management of wetlands. Classification system developed by the USFWS(1979) is hierarchical progresses from systems and subsystems at general levels to classes, subclasses, dominance types, and habitat modifiers. Systems and subsystems are delineated according to major physical attributes such as tidal flushing, ocean-derived salts, and the energy of flowing water or waves. Classes and subclasses describe the type of substrate and habitat or the physiognomy of the vegetation or faunal assemblage. Wetland classes are divided into physical types and biotic types. For the wise management of wetlands in Korea, this study was carried out to examine methodology of USFWS classification system and discuss its application for Korean wetland hydrogeomorphic units already known. Seven wetland types were chosen as study sites in Korea divided into some different types based on USFWS system. Three wetland types belonging to palustrine system showed no difference between Wangdungjae wetland and Mujechi wetland, but Youngnup of Mt. Daeam was different from the former two types at the level of dominant types. This fact means that setting of classification system for management of wetland is needed. Although we may never know much about the wetland resources that have been lost, there are opportunities to conserve the riches that remain. Extensive inventory of all wetland types and documentation of their ecosystem functions are vital. Unique and vulnerable examples in particular need to be identified and protected. Furthermore, a framework with which to demonstrate wetland characteristics and relationships is needed that is sufficiently detailed to achieve the identification of the integrity and salient features of an enormous range of wetland types.

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Study on the Improvement of Gill Nets and Trap Nets Fishing for the Resource Management at the Coastal Area of Yellow Sea - On the Entrapping Behavior of Fishes into Trap Nets in the Water Tank Experiment - (서해구 자원관리형 자망ㆍ통발 어구어법 기술개발에 관한 연구 - 수조에서의 통발에 대한 어군의 입롱행동 -)

  • 장호영;조봉곤;고광수;한민숙
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.39 no.1
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    • pp.56-62
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    • 2003
  • To investigate the entrapping behavior of blue crab, rock shell and green ling, which are mainly caught with the other trap nets in the coastal area of Yellow Sea, by the using duration of trap nets through the water tank experiment. We select the three kinds of trap nets which have different using duration such as new, 6 months and 12 months used one, and observe the entrapping ratio into the trap nets, respectively. In the mean while, in order to obtain the basic data for the estimate of mesh selectivity of the other trap nets, the entrapping behavior into the trap nets for green ling which has high activity compared to blue crab and rock shell, are examined to the three kinds of mesh size (35mm, 50mm and 65mm). The results are as follows ; 1. The mean entrapping ratio of blue crab by the using duration of trap nets in high with 4.4 fishes (44.0%) in the 6 months used one, become lower with 2.9 fishes (28.0%) in the new one, and with 2.0 fishes (20.0%) in the 12 months used one. 2. The mean entrapping ratio of rock shell by the using duration of trap nets in high with 7.3 fishes (36.7%) in the new one, and become lower with 7.2 fishes (35.8%) in the 6 months used one, and with 5.7 fishes (28.3%) in the 12 months used one. 3. The mean entrapping ratio of green ling by the using duration of trap nets in high with 3.4 fishes (34.0%) in the 6 months used one, and become lower with 3.0 fishes (30.0%) in the new one, and with 2.8 fishes (28.0%) in the 12 months used one. 4. The mean residual ratio of green ling by the mesh size of trap nets is high with 2.4 fishes (24.0%) in the 35mm mesh size, and become lower with 2.2 fishes (22.0%) in the 50mm mesh size and 2.0 fishes (20.0%) in the 65mm mesh size.

Base-metal Mineralization in the Cretaceous Gyeongsang Basin and Its Genetic Implications, Korea: the Haman-Gunbug-Goseong(-Changwon) and the Euiseong Metallogenic Provinces (한국 경상분지 백악기 비철금속 광화작용과 그 성인적 의의: 함안-군북-고성(-창원) 및 의성 광상구를 중심으로)

  • 이상렬;최선규;소칠섭;유인창;위수민;허철호
    • Economic and Environmental Geology
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    • v.36 no.4
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    • pp.257-268
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    • 2003
  • The Cretaceous magmatism in the Gyeongsang Basin, Korea, led to the formation of two contrasting metallogenic provinces: the Haman-Gunbug-Goseong(-Changwon) (HGGC) and the Euiseong (EU). The mineralization in the HGGC metallogenic province represents copper, gold and iron of porphyry-related deposits that display close relationships in time and space with subvolcanic granitoids. Much of copper-gold-forming events in this province are consistently constrained to the period between ca. 89 and 81 Ma. The hydrothermal systems of copper-gold vein deposits in the HGGC province are associated with ore-forming fluids of high to intermediate temperature (300∼50$0^{\circ}C$) with high salinity (20∼55 equiv. wt. % NaCl). The ore-forming fluids become progressively more diluted by the incorporation of decreased quantities of magmatic water further from the nearby intrusion, suggesting significant input and fluid mixing of a meteoric water component to the magmatic fluids during the late stage of geothermal systems. In contrast, the EU metallogenic province is characterized by polymetallic vein deposits that are consistently constrained to a period of 78∼60 Ma. The geothermal systems of polymetallic vein deposits in the EU province are derived from a narrow range of intermediate temperature (200∼40$0^{\circ}C$) with relatively low salinity(1∼7 equiv. wt.% NaCl). It may represent a mixed fluid of magmatic and meteoric waters. The base-metal mineralization in the Gyeongsang Basin shows a close spatial and temporal distinction between the proximal environment derived from shallow-level granitoids in the southwestern HGGC province and the distal condition derived from volcanic environments in the northwestern EU province.

The Origin and Evolution of the Mesozoic Ore-forming Fluids in South Korea: Their Genetic Implications (남한의 중생대 광화유체의 기원과 진화특성: 광상 성인과의 관계)

  • Choi, Seon-Gyu;Pak, Sang-Joon
    • Economic and Environmental Geology
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    • v.40 no.5
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    • pp.517-535
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    • 2007
  • Two distinctive Mesozoic hydrothermal systems occurred in South Korea: the Jurassic/Early Cretaceous(ca. $200{\sim}130$ Ma) deep-level ones during the Daebo orogeny and the Late Cretaceous/Tertiary(ca. $110{\sim}45$ Ma) shallow hydrothermal ones during the Bulgugsa event. The Mesozoic hydrothermal system and the metallic mineralization in the Korean Peninsula document a close spatial and temporal relationship with syn- to post-tectonic magmatism. The calculated ${\delta}^{18}O_{H2O}$ values of the ore-forming fluids from the Mesozoic metallic mineral deposits show limited range for the Jurassic ones but variable range for the Late Cretaceous ones. The orogenic mineral deposits were formed at relatively high temperatures and deep-crustal levels. The mineralizing fluids that were responsible for the formation of theses deposits are characterized by the reasonably homogeneous and similar ranges of ${\delta}^{18}O_{H2O}$ values. This implies that the ore-forming fluids were principally derived from spatially associated Jurassic granitoids and related pegmatite. On the contrary, the Late Cretaceous ferroalloy, base-metal and precious-metal deposits in the Taebaeksan, Okcheon and Gyeongsang basins occurred as vein, replacement, breccia-pipe, porphyry-style and skarn deposits. Diverse mineralization styles represent a spatial and temporal distinction between the proximal environment of subvolcanic activity and the distal to transitional condition derived from volcanic environments. The Cu(-Au) or Fe-Mo-W deposits are proximal to a magmatic source, whereas the polymetallic or the precious-metal deposits are more distal to transitional. On the basis of the overall ${\delta}^{18}O_{H2O}$ values of various ore deposits in these areas, it can be briefed that the ore fluids show very extensive oxygen isotope exchange with country rocks, though the ${\delta}D_{H2O}$ values are relatively homogeneous and similarly restricted.

Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2014 (설비공학 분야의 최근 연구 동향: 2014년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.7
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    • pp.380-394
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    • 2015
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.

Base Study Related with Development of Natural Bio-Adhesives Using Seaweeds (해초류를 이용한 천연 바이오 접착제 개발 기반 연구)

  • Han, Won-Sik;Oh, Seung-Jun;kim, Young-Mi;Lee, You-Jin;Kim, Ye-Jin;Park, Min-Seon;Wi, Koang-Chul
    • Journal of Conservation Science
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    • v.34 no.6
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    • pp.595-604
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    • 2018
  • In this study, in a bid to develop natural bioadhesives for paper craft, the hanji industry, and preserving cultural assets, complex polysaccharides were extracted from brown and red algae and used as an ingredient in adhesives. Brown algae include sea trumpet, kelp, sea oak, and sea mustard, whereas red algae include Pachymeniopsis elliptica agar-agar weed, Gloiopeltis tenax, and hunori. The polysaccharides were extracted after transforming them from non-aqueous Ca complexes contained in each of the brown and red algae into water-soluble polysaccharides containing alkali metals with a solubility level of 1. and extracted Subsequently, only the polysaccharides were extracted using alcohol precipitation. The adhesion tensile strengths of kelp, a brown algae, and Pachymeniopsis elliptica, a red algae, were 21.58 and 32.99 kgf, respectively. They thus demonstrated better adhesion than that of solid glue products such as water plants (18.45 kgf) and glue sticks (20.45 kgf). The extraction yield of these polysaccharides is supposed to be determined according to their extracted environments; however, no difference in adhesion strength was seen. Further, it was found that the shapes of polysaccharides were determined by their growing environment instead of extraction environment. Use of multi-step alcohol precipitation method during extraction enabled the removal of the constituents except protein and other polysaccharides, thereby demonstrating a stable outcome without cultivation of mold. Furthermore, there was no occurrence of mold even after production of the adhesives by the simple solution method, which demonstrates the adhesive's potential as an environment-friendly adhesive material.

Longitudinal Pattern of Large Wood Distribution in Mountain Streams (산지계류에 있어서 유목의 종단적 분포특성)

  • Seo, Jung Il;Chun, Kun Woo;Kim, Min Sik;Yeom, Kyu Jin;Lee, Jin Ho;Kimura, Masanobu
    • Journal of Korean Society of Forest Science
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    • v.100 no.1
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    • pp.52-61
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    • 2011
  • Whereas recent researches have elucidated the positive ecological roles of large wood (LW) in fishbearing channels, LW is also recognized as a negative factor of log-laden debris flows and floods in densely populated areas. However in Republic of Korea, no study has investigated longitudinal variations of LW distribution and dynamic along the stream corridor. Hence to elucidate 1) physical factors controlling longitudinal distribution of LW and 2) their effect on variation in LW load amount, we surveyed the amount of LW with respect to channel morphology in a mountain stream, originated from Mt. Ki-ryong in Inje, Gangwondo. Model selection in the Generalized Linear Model procedure revealed that number of boulder (greater than or equal to 1.0 m in diameter), bankfull channel width and their interaction were the best predictors explaining LW load volume per unit channel segment area (unit LW load). In general, boulders scattered within small mountain streams influence LW retention as flow obstructions. However, in this study, we found that the effect of the boulders vary with the channel width; that is, whereas the unit LW load in the segment with narrow channel width increased continuously with increasing boulder number, it in the segment with wide channel width did not depend on the boulder number. This should be because that, in two channels having different widths, the rates of channel widths reduced by boulders are different although boulder numbers are same. Our findings on LW load varying with physical factors (i.e., interaction of boulder number and channel width) along the stream corridor suggest understanding for longitudinal continuum of hydrogeomorphic and ecologic characteristics in stream environments, and these should be carefully applied into the erosion control works for systematic watershed management and subsequent disaster prevention.

Effects of Particle Size and Pyrolysis Temperature of Oyster Shell on Change of Coastal Benthic Environment (굴 패각의 입경 및 소성 온도에 따른 연안 오염 저서환경 변화 연구)

  • Jeong, IlWon;Woo, Hee-Eun;Lee, In-Cheol;Yoon, SeokJin;Kim, Kyunghoi
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.26 no.7
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    • pp.873-880
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    • 2020
  • After pre-treatment of oyster shells according to particle size (0 ~ 1, 1 ~ 2, 2 ~ 5 mm) and pyrolysis temperature (400(P400), 500(P500), 600(P600), 800(P800)℃), changes in the properties of sediments mixed with pre-treated oyster shells were investigated. The primary component of the oyster shell was changed from CaCO3 to CaO at temperatures above 700℃. The Ca2+ concentration in P800 was 790 mg/L, which was 2 ~ 3 times higher than those in the control and other experimental samples. Ca2+ elution significantly increased at the pyrolysis temperature over than 600℃. In oyster shells pyrolyzed over 600℃, the pH of the pore water increased by 0.1 ~ 0.5, due the hydrolysis of CaO formed by the pyrolysis of CaCO3. The PO4-P of the overlying and pore water in P600 and P800 were 0.1 ~ 0.2 mg/L lower than those of the control. The increased pH and elution of Ca2+ from oyster shells should suppress the upwelling of PO4-P from the sediment. Based on the above results, it was confirmed that the pyrolysis temperature of oyster shells influenced NH3-N and PO4-P concentrations in the sediment; however, the particle size of oyster shells had little effect. The results of this study can be used as a foundation for research on the use of pyrolyzed oyster shells to improve low-contamination coastal benthic environments.