• Title/Summary/Keyword: desiccation

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The Rice Quality and Chemical Characteristics Affected by Moisture Content and Drying Delay Time after Harvest in Rice (벼 수확 후 수분함량별 건조지연에 따른 쌀 품위 및 화학성)

  • Kwon, Suk-Ju;Song, Eun-Ju;Kwon, Young-Rip;Choi, Dong-Chil;Choi, Yeong-Geun;Kwon, Tae-Oh
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.51 no.spc1
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    • pp.35-41
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    • 2006
  • This study was conducted to establish the post-harvest management system in rice. Harvested hulled rice was gathered into large-scale bag and combine bag, in which the rice quality and the influence on quality change were investigated on various storage periods and moisture contents. Moisture content of hulled rice ranged from 23.7% to 28.8% on different harvest times, which grew lower as harvesting time was delayed. When desiccation was retarded hulled rice in large scale bag was changed in color and emitted an of offensive odor in 3 days and that in combine bag showed similar symptom in 4 days. Inner temperature in large scale bag was changed a lot when the storage period was prolonged and also the moisture content was higher while that in combine bag increased regularly corresponding to the moisture content at the time of harvest. Moisture content of hulled rice stored in large-scale bag increased 2 days after harvest and the more moisture content showed the more increased tendency, while in the case of combine bag the moisture content was not changed much whether the hulled rice contained low or high moisture content in harvesting. As desiccation was delayed fatty acid increased much more in large-scale bag than in combine bag even though protein and amylose contentwere not changed. As desiccation was delayed more and hulled rice contained moisture more in harvesting head rice ratio of brown rice decreased and green-kerneled rice and damaged grain ratio increased and quality of milled rice also became deteriorated. As a result, desiccation day to minimize the deterioration of rice quality was estimated 1-2 days in large scale bag and 2-3 days in combine bag after harvesting.

Optimal Desiccation Condition and Moisture Content of Dehisced Seeds of Ginseng (Panax ginseng C.A. Meyer) for Cryopreservation (인삼 개갑종자의 초저온동결보존을 위한 최적 건조조건과 수분함량)

  • Yoon Ju-Won;Kim Haeng-Hoon;Lee Jang-Hoo;Choi Jin-Kook;Lee Sung-Sik;Choi Yu-Mi;Kim Tae-San
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.50 no.6
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    • pp.406-410
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    • 2005
  • This study was conducted to establish the efficient protocols of the germination and cryopreservation of dehisced Korean ginseng seeds for long-term germ­plasm conservation. $GA_3$ and BA treated on seed for 24 hr facilitated germination at 5 and $10^{\circ}C$. Germination percentage of desiccated seeds was decreased under moisture content (MC) of below $7.2\%$. Dehisced ginseng seeds were dried under airflow of laminar floor cabinet and seed drying room. The high levels (more than $90\%$) of germination after cryogenic exposure were obtained after drying under vertical airflow of laminar floor for 12-30 hours (MC $10.6{\~}7.2\%$). Decrease in germination percentage of ginseng seeds due to desiccation damage and freezing injury was observed at MC of below $7.2\%$ and of above $12.1\%$, respectively. Therefore, MC of ginseng seeds need to be controlled with a range of $8{\~}10\%$ to avoid damages from both desiccation and freezing.

Lakes and Palaeolakes in Mongolia and Northwestern China

  • Michael, Walther;Bernd, Wunnemann;Altangerel, Tshimeksaichan
    • The Korean Journal of Quaternary Research
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    • v.18 no.2 s.23
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    • pp.17-17
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    • 2004
  • The Pleistocene lake level and climate development is described by proxies from sediment, pollen and diatom records in Mongolia and Northwest-China. It could be proved that higher lake levels seem to have existed during the old and mid Pleistocene period interpreted on the base of geomorphological and sedimentological reords. They are dated in a relativ time scale. The lake basins are filled up to 300 m by limnic deposits, which foused on a constant water balance of more than 700.000 years. Late Glacial and Holocene lake level fluctuations and climate changes can be proved by biostratigraphic records pointing to dry and wet phases. Only for the youngest history desiccation of some lakes are related to human impact.

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Comparison of the effects of physico-chemical factors on the zonation and vertical distribution of benthic microalgal communities in the tidal flats of south-west Korea (한국 남서부 갯벌의 저서성 미세조류의 대상분포와 수직분포에 미치는 이화학적 요인의 효과에 관한 비교)

  • 이학영
    • Journal of Environmental Science International
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    • v.11 no.6
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    • pp.529-535
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    • 2002
  • Efffcts of physico-chemical factors on the zonation and vertical distribution of benthic microalgal communities in the tidal flats of Youngkwang and Canaiin, Korea, were studied. Concentrations of nutrients were low throughout the study period. A 38 species of benthic microaigae was identified. Most of the algae were pennate diatoms with small size. Cell numbers at silty sediments were higher than sandy sediments, and showed high patchy distribution. Zonal distributions of benthic microalgae showed higher variation from silty sediment than sandy sediments. Benthic microalgae showed vertical migration within the upper few mm of sediment with periodicity closely related to tidal cycles. Maximum cells were observed from 0 mm depth both sandy and silty sediments. Cells of benthic microalgae in the 1 - 2 mm depth decreased after desiccation of sediments. The variation of cells was higher at sandy sediments than silty sediments. Cell numbers of benthic microalgae showed no positive relationships with pH and nutrinets except NH$_4$-N.

Isolation and Characterization of Epidermal Mucus from Hirudo nipponia

  • Lee, Ju-Yun;Joe, Cheol-O;Kang, Ke-Won
    • BMB Reports
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    • v.29 no.3
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    • pp.248-252
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    • 1996
  • The epidermal organ of the leech contains a complex glycoprotein molecule of mucus. The mucus excreted from annelids plays Significant role in protection against desiccation and parasites. Mucus from the Korean native leech, H. nipponia, was investigated for biochemical characteristics for possible development of biomaterials of cosmetic and pharmaceutical agents. The leech skin mucus was heavily glycosylated mucin-like protein with a high molecular weight comprised 80% carbohydrate and 20% protein. Threonine, serine, and glycine were the major components of the isolated protein and these accounted for 50% of total amino acids. The carbohydrate portion contained glucosamine, galactosamine. galactose, glucose. mannose and sialic acid in oligosaccharide form linked with threonine and serine residues of the glycoprotein.

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The Colonization of Lemna paucicostata and Spirodela polyrhiza (좀개구리밥 ( Lemna paucicostata ) 과 개구리밥 ( Spirodela polyrhiza ) 의 定着能力)

  • Park, Bong-Kyu;In-Hye Oh
    • The Korean Journal of Ecology
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    • v.8 no.3
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    • pp.141-146
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    • 1985
  • Colonization ability was studied with Lemna paucicostata and Spirodela polyrhiza. Colonization ability of each species was defind as its ability to; (1) tolerate to desiccation, (2) multiplicate and spread in the new habitat, (3) inhibit the other species competitively. Lemna paucicostata was inferior to Spirodela polyrhiza in ability (1), but superior to Spirodela polyrhiza in abilities (2) and (3). Whenever lemna paucicostata and Spirodela polyrhiza are colonized recently, only these three abilities can not explain which species is better colonist. Even short unsuitable periods would eliminate a species, with time lag occurring before recolonization. This would result in a discontinuous of the species concerned.

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Nonlinear calculation of moisture transport in underground concrete

  • Ba, M.F.;Qian, C.X.;Gao, G.B.
    • Computers and Concrete
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    • v.13 no.3
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    • pp.361-375
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    • 2014
  • The moisture transport in underground concrete was experimentally investigated and the nonlinear model of moisture transport considering the effects of water diffusion, hydration of cementicious materials and water permeability was proposed. The consumed moisture content by self-desiccation could be firstly calculated according to evolved hydration degree of cement and mineral admixtures. Furthermore, the finite differential method was adopted to solve the moisture transport model by linearizing the nonlinear moisture diffusion coefficient. The comparison between experimental and calculated results showed a good agreement, which indicated that the proposed moisture model could be used to predict moisture content evolution in underground concrete members with drying-wetting boundaries.

Expansion Model of Cement Paste using Expansive Additive (팽창재를 혼입한 시멘트 경화체의 팽창모델)

  • Park, Sun-Gyu;Takahumi, Noguchi;Kim, Moo-Han
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.11a
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    • pp.789-792
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    • 2005
  • Development of high-strength concrete and improved durability has brought new opportunities to the construction industry. However, some attention was given to characteristics of such concrete, in particular with respect to their cracking sensitivity. It has been argued and demonstrated experimentally that a low water/cement ratio concrete undergoes shrinkage due to self-desiccation. This so-called autogenous shrinkage cracking is a major concern for concrete durability. One possible method to reduce cracking due to autogenous shrinkage is the addition of expansive additive. Tests conducted by many researches have shown the beneficial effects of addition of expansive for reducing the risk of shrinkage-introduced cracking. This paper aimed at forecasting deformation of high strength cement paste with expansive additive for early age.

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Early Age Shrinkage by Self-Desiccation in Ultra-High-Strength Concrete

  • Yoo, Doo-Yeol;Min, Kyung-Hwan;Yang, Jun-Mo;Yoon, Young-Soo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.469-470
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    • 2010
  • The high-strength concrete(HSC) compared to normal concrete represents higher autogenous shrinkage due to lower water-to-binder ratio(W/B) and supplementaries, fly ash(FA) and granulated blast-furnace slag(BFS), etc. The potential of early age cracking which reduces durability of concrete structures is normally influenced by autogenous shrinkage and degree of restraint. Therefore, this paper studies on the evaluation of the characteristics of autogenous shrinkage for HSC, ultra-high-strength concrete(UHSC) containing admixtures by experimental test and the test results are compared with existed prediction models.

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Evolution under unpredictable environmental conditions: quantitative genetics of larval life-history traits in a myobatrachid frog Crinia georgiana

  • Smith, Michael J.;Jang, Yikweon
    • Animal cells and systems
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    • v.16 no.5
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    • pp.425-430
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    • 2012
  • The southwestern Australian frog Crinia georgiana (Anura; Myobatrachidae) inhabits ephemeral pools in which the tadpoles often face desiccation. Under these conditions selection on tadpoles can be severe and can directly affect fitness during the aquatic as well as the terrestrial developmental stages. A quantitative genetic study using a half-sib breeding design was conducted to understand the genetic effects on larval life-history traits. We found no significant additive genetic variance in any of larval traits. Except for hatching period, heritability estimates based on females were high in egg size, larval period, snout-vent length, and weight at metamorphosis, suggesting non-additive genetic effects. These results indicate that any response to selection during hatching and larval periods should be predominately governed by non-additive genetic effects in C. georgiana.