• Title/Summary/Keyword: Loess

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Development of Loess Composite for the Control of Phosphorus Release from Lake Sediments (호소 퇴적층으로부터 용출되는 인 제거를 위한 황토 복합체 개발)

  • Shin, Gwan-Woo;Kim, Keum-Yong;Lee, Sang-Ill
    • Journal of Korean Society on Water Environment
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    • v.28 no.1
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    • pp.50-56
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    • 2012
  • In this study, loess composites, loess with lanthanum and with aluminum, were made and evaluated for treatment of phosphorus removal in natural water system. Desiccation method for production of loess composite was superior to centrifugation method in obtaining high concentrated composites of lanthanum and aluminum. Washing of loess lanthanum composite by water did not deteriorat the lanthanum concentration in the composite, but this lowered the aluminum concentration of loess aluminum composite. Total of 15 and 37.5% of aluminum contents were removed after first washing treatment in aluminum loess of 0.05% and 0.1% respectively. However, no more aluminum loss was monitored with increase of washing times. Phosphorus removal efficiencies were not decreased with washed loess aluminum composite. Phosphorus removal was successfully achieved by adsorption of phosphate to loess composite at pH range of 5.0 ~ 8.0. Freundlich and Langmuir adsorption isotherm was observed in the adsorption of phosphate for loess composite. Dosages of 0.05% and 0.1% lanthanum composite for 95% of phosphorus removal could reduce its usage amount to 25% and 50%, respectively, comparing with dosage of loess alone. Dosages of 0.05% and 0.1% aluminum composite could reduce its usage amount to 48% and 63%, respectively.

Effects of Loess Application in Coastal Benthic Ecosystem (적조 방제용 황토살포가 연안 저서생태계에 미치는 영향)

  • Park, Chi-Hyun;Lee, Byoung-Ho
    • Journal of Environmental Science International
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    • v.15 no.11
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    • pp.1035-1043
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    • 2006
  • Large scale of fish kills by red tides has been occurred every year in coastal water fisheries of Korea. To suppress red tide spreading out over the south coastal water of the Korean Peninsula large amount of loess has been applied every year because loess is known to be effective in removing red tide organisms. Effects of loess application in ecosystem of underwater near sea shore were investigated with some physical characteristics of loess. Loess used for the red tide reduction consisted of very fine particles, of which size was mostly less than 0.1 mm. Particles of loess blocked light penetration, which is essential for the underwater ecosystem. Loess also pushed pH down by the hydrolysis activities of aluminium and iron It was found that underwater ecosystems where loess was applied near sea shore were devastated. Sea plants such as sea weeds were gone leaving only their roots. Clams and snails were dead under the loess dust blanket. And fishes were not found at all where loess has been sprayed lot long time. It was found that even if loess has some capacity to reduce red tide temporarily, loess application should be slopped to protect underwater ecosystems.

Investigation of the present production trend of building material in relation to loess (황토를 이용한 건자재의 생산현황에 대한 조사연구)

  • Cho, Chang-Hee;Kim, Jin-Goan;Lee, Byeong-Ho
    • KIEAE Journal
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    • v.12 no.3
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    • pp.107-114
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    • 2012
  • This is a study that surveyed and analyzed the present status of producing loess construction materials in Korea from 2006 to 2011. The findings are as follows. 1) More than 70% of loess construction material manufacturers are distributed in the capital area. Chungcheong-do and Gyeonggi-do are grown by about 20% on the annual average. 2) Shape of loess brick is possessed mostly by a rectangular parallelepiped. A hole shape, which has 1~5 holes among these things, is possessing a majority. 3) It was indicated to be 42 days as material age for the compressive strength, to be about 2.7Mpa for both extrusion and compression, and to be about 30% for absorptance. 4) Among the whole loess material manufacturers, it accounts for 87 for loess brick 66% for loess mortar and more than 39% for loess paint, but within 10%~15% for other loess products. 5) The main specifications of loess brick are $300{\times}150{\times}150,\;300{\times}150{\times}100,\;300{\times}200{\times}150,\;300{\times}150{\times}200$ in order of the output of 74kinds of loess bricks. 6) In order to improve the strength of building materials, mortar and concrete used loess, it is necessary to examine closely about the effect of ceramic binder and cement on loess products.

Characteristics of Loess and Loessial Slopes in Gansu Province, China (중국 감숙성의 황토특성과 황토사면특성)

  • 홍성완
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.03a
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    • pp.47-78
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    • 1999
  • About 440,000 $\textrm{km}^2$, about twice the size of the Korean Peninsula is covered by loess deposits in China. Along the middle reaches of the Huanghe River, mainly in Shaanxi and in Gansu province loess plateau covers vast area amounting to 273,000 $\textrm{km}^2$ Chinese studies on loess and loessial slopes are summarized. And some of the U. S. study and others are also presented for comparison.

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Additive Materials to Reduce the Amount of Loess Being Applied for Red Tide Removal on Coastal Water (적조방제용 황토살포의 양을 줄일 수 있는 첨가제에 대한 연구)

  • Park, Chi-Hyun;Lee, Byoung-Ho
    • Journal of Environmental Science International
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    • v.16 no.6
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    • pp.745-750
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    • 2007
  • Large scale of loess has been applied on the south - sea shore of the Korean peninsula to treat red tides, due to many fishery's devastation by red tides every year. However, coastal ecosystem is ruined by the huge amount of loess applied every year. Almost all creatures, living under water such as sea weeds, clams, and fishes, where loess was applied, are disappearing. In this paper, alternative methods of the loess application are investigated. The amount of loess could be reduced by the alternative methods, Especially, loess mixed with calcium oxide has excellent effects to reduce Cochlodinium polykrikoides numbers. It was found that when loess is used with calcium oxide(CaO), removal efficiency of red tides is highly increased. Moreover, the amount of loess could be reduced dramatically.

A Study on the Dyeing according to Kinds of Loess (황토 종류에 따른 염색성 연구)

  • 강영의;박순옥
    • Textile Coloration and Finishing
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    • v.15 no.6
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    • pp.39-46
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    • 2003
  • The experiments about dyeing concentration, temperature and time were done using yellow, red and purple loess as natural inorganic dyes in order to verify a degree of dyeing, characteristics of color and fastness. The results were as following; 1. As a result of analyzing components of loess, purple loess was much than other loess in quartz component and coarse particles contained. This affected to the degree of dyeing. 2. The stronger dyeing concentration was, the more the degree of dyeing was improved, and yellow loess containing fine particles was the best in the degree of dyeing. 3. When it was dyed with raising up to $100^\circ{C}$ for 10 minutes after stirring for 20 minutes at $60^\circ{C}$, was better than on starting at $40^\circ{C}$ or $80^\circ{C}$ in the degree of dyeing. Also yellow loess was the best in these experiments. 4. Washing fastness of loess was low such as other natural dyes, but dyeing wasn't transferred to other textiles. On the other hand, light fastness of it was very excellent and rubbing fastness was relatively good as 3~3.5.

Characterization of a Loess Module for Manufacturing Loess Red Ginseng

  • Kim, Il-Chool;Yang, Jung-Hwan;Hur, Sang-Sun
    • Journal of Ginseng Research
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    • v.34 no.4
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    • pp.282-287
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    • 2010
  • An optimized manufacturing process was developed for the production of high-quality loess red ginseng using a hybrid process in which loess (yellow earth) was incorporated into the conventional ginseng manufacturing process system. We designed conventional ginseng processing facilities and prepared the loess module by baking loess that contained 42% water at $860^{\circ}C$ for 8 h. The loess module showed excellent performance in deodorization and humidity control. The optimum steaming temperature at which maximum expansion of starch organisms occurred was 90 to $98^{\circ}C$.

Decolorization of Acid Orange II from Aqueous Solutions using Loess (황토를 이용한 Acid Orange II의 색도제거)

  • Park, Jae Hong
    • Journal of Korean Society on Water Environment
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    • v.27 no.2
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    • pp.141-146
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    • 2011
  • Loess, a natural clay, was evaluated as an adsorbent for the decolorization of Acid Orange II, an azo and reactive dye, from aqueous solution. Adsorption studies were performed at $30^{\circ}C$ and the effect of reaction time, loess dosage, initial concentration, loess particle size, pH, agitation rate were investigated to determine the optimum operation conditions. The removal efficiencies of color were measured to evaluate the effectiveness of loess. From this study, it was found that optimal reaction time was 10 min. Color removal efficiencies of Acid Orange II were increased as higher loess dosage, initial concentration and agitation rate. However, color removal efficiencies decreased when pH is high and loess particle becomes large. Adsorption of Acid Orange II fitted to the pseudo-second-order rate kinetics more than first-order rate kinetics. Langmuir and Freundlich adsorption isotherm constants and correlation coefficients were calculated and compared. It was concluded that the adsorption data of Acid Orange II onto loess fitted to the Freundlich model more than Langmuir model.

Loess Dyeing of Soybean Fabrics (대두직물의 황토염색)

  • Lee, Sol;Lee, Shin-Hee
    • Fashion & Textile Research Journal
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    • v.17 no.6
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    • pp.1004-1012
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    • 2015
  • The purpose of this study is to investigate the loess dyeability of soybean fabric using loess as colorants. Recent days, various textile products such as inner wears, sheets and interior goods are manufactured using materials dyed with loess emphasizing its improved metabolism, anti-bacterial, deodorizing properties, and far infrared ray emissions. Soybean fabric was dyed with loess solution according to concentration of loess, dyeing temperature and dyeing time. To improve washing fastness, soybean fabric and dyed soybean fabric with loess were mordanted by mordanting agents such as sodium chloride(NaCl), Acetic acid(CH3COOH) and Aluminium Potassium Sulfate(AlK(SO4)2·12H2O). Dyeability and color characteristics of dyed soybean fabric were obtained by CCM observation. Particle size distribution of loess, the dyeability(K/S) of soybean fabric, morphology and washing durability of loess dyed soybean fabric were investigated. The results obtained were as follows; Mean average diameter of loess was 1.08µm. The main components of loess used in this study were silicon dioxide(SiO2), aluminium oxide(Al2O3), and iron oxide(Fe2O3). The content of these three component was above 75 weight %. The dyeability of soybean fabric was increased gradually with increasing concentration of loess. The optimum dyeing temperature and dyeing time were 90℃ and 60minutes expectively. The fastness to washing according to concentration of loess and mordanting method indicated good grade result as more than 4 degree in all conditions.

Hysteretic behaviors of pile foundation for railway bridges in loess

  • Chen, Xingchong;Zhang, Xiyin;Zhang, Yongliang;Ding, Mingbo;Wang, Yi
    • Geomechanics and Engineering
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    • v.20 no.4
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    • pp.323-331
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    • 2020
  • Pile foundation is widely used for railway bridges in loess throughout northwestern China. Modeling of the loess-pile interaction is an essential part for seismic analysis of bridge with pile foundation at seismically active regions. A quasi-static test is carried out to investigate the hysteretic behaviors of pile foundation in collapsible loess. The failure characteristics of the bridge pile-loess system under the cyclic lateral loading are summarized. From the test results, the energy dissipation, stiffness degradation and ductility of the pile foundation in loess are analyzed. Therefore, a bilinear model with stiffness degradation is recommended for the nonlinearity of the bridge pier-pile-loess system. It can be found that the stiffness of the bridge pier-pile-loess system decreases quickly in the initial stage, and then becomes more slowly with the increase of the displacement ductility. The equivalent viscous damping ratio is defined as the ratio of the dissipated energy in one cycle of hysteresis curves and increases with the lateral displacement.