• Title/Summary/Keyword: RHA

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The applicability of Freundlich's isotherm model for the leaching of solidified hazardous waste using cementitious binders

  • Youn Jong Ho;Lee Heon Mo;Jeong Byung Gon;Chung Yong Hyun
    • Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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    • v.2 no.1
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    • pp.9-19
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    • 1998
  • A laboratory study was conducted to investigate the immobilization of the laboratory waste sludge, mainly from chemical oxygen demand (COD) waste, using cementitious binders. The binders were: Ordinary Portland Cement (OPC), and lime-Rice Husk Ash(RHA) cement. The economic evaluation was done for three different kinds of cementitious binders, namely, OPC, Portalnd Rice Husk Ash Cement (PRHAC) which contained rice husk ash 50 percent by dry weight, and lime-RHA cement. The result showed that lime-RHA cement was the cheapest. The applicability of Freundlich's desorption isotherm was studied to assess the teachability of sludges. The teachability of cement mortars was found to follow the desorption isotherms. Therefore, it was concluded that based on this test, the leachate concentrations of the solidified heavy metals could be predicted, approximately by the Freundlich's isotherm desorption modeling.

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Soil stabilization of clay with lignin, rice husk powder and ash

  • Canakci, Hanifi;Aziz, Aram;Celik, Fatih
    • Geomechanics and Engineering
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    • v.8 no.1
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    • pp.67-79
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    • 2015
  • This article presents the result of laboratory study conducted on expansive soil specimens treated with lignin, rice husk powder (RHP) and rice husk ash (RHA). The amount of lignin produced from paper industry and RHP were varied from 0 to 20% and RHA from 0 to 10% by weight. The treated specimens were subjected to unconfined compressive strength (UCS),swelling test and Atterberg limit tests. The effect of additives on UCS and atterberg limit test results were reported. It was observed that the additives and curing duration had a significant effect on the strength value of treated specimens. Generally (except the sample treated with 20% RHP for 3-day) with increasing additive and curing duration the UCS value increases. A RHP content of 15% was found to be the optimum with regard to 3-day cure UCS.

Update in the etiology and treatment of sexual precocity (사춘기 조숙증의 원인 및 치료의 최신지견)

  • Park, Mi Jung
    • Clinical and Experimental Pediatrics
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    • v.49 no.7
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    • pp.718-725
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    • 2006
  • The pubertal activation of gonadotrophin releasing hormone(GnRH) requires coordinated changes in excitatory or inhibitory amino acids, growth factors, and a group of transcriptional regulators. The age of onset of puberty is progressing to younger age. Factors affecting early puberty include genetic traits, nutrition(body fat) and exposure to endocrine disrupting chemicals. In rapidly progressing central precocious puberty, gonadotrophin releasing hormone(GnRH) agonists(GnRHa) appear to increase final height if treated early stage. Further large scaled long-term follow-up study of the effects of GnRHa on final height is needed.

The applicability of Freundlichs isotherm model for the leaching of solidified hazardous waste using cementitious binders

  • Jong Ho Youn;Heo
    • Journal of Environmental Science International
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    • v.2 no.1
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    • pp.9.2-19
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    • 1993
  • A laboratory study was conducted to investigate the immobilization of the laboratory waste sludge, mainly from chemical oxygen demand (COD) waste, using cementitious binders. The binders were: Ordinary Portland Cement (OPC), and lime-Rice Husk Ash (RHA) cement. The economic evaluation was done for three different kinds of cementitious binders, namely, OPC, Portaind Rice Husk Ash Cement (PRHAC) which contained rice husk ash U percent by dry weight, and lime-RHA cement. The result showed that lime-RHA cement was the cheapest. The applicability of Freundlich's desorption isotherm was studied to assess the teachability of sludges. The teachability of cement mortars was found to follow the desorption isotherms. Therefore, it was concluded that based on this test, the leachate concentrations of the solidified heavy metals could be predicted, approximately by the Freundlich's isotherm desorption modeling.

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The role of gonadotropin-releasing hormone agonists in female fertility preservation

  • Lee, Jae Hoon;Choi, Young Sik
    • Clinical and Experimental Reproductive Medicine
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    • v.48 no.1
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    • pp.11-26
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    • 2021
  • Advances in anticancer treatments have resulted in increasing survival rates among cancer patients. Accordingly, the quality of life after treatment, particularly the preservation of fertility, has gradually emerged as an essential consideration. Cryopreservation of embryos or unfertilized oocytes has been considered as the standard method of fertility preservation among young women facing gonadotoxic chemotherapy. Other methods, including ovarian suppression and ovarian tissue cryopreservation, have been considered experimental. Recent large-scale randomized controlled trials have demonstrated that temporary ovarian suppression using gonadotropin-releasing hormone agonists (GnRHa) during chemotherapy is beneficial for preventing chemotherapy-induced premature ovarian insufficiency in breast cancer patients. It should also be emphasized that GnRHa use during chemotherapy does not replace established fertility preservation methods. All young women facing gonadotoxic chemotherapy should be counseled about and offered various options for fertility preservation, including both GnRHa use and cryopreservation of embryos, oocytes, and/or ovarian tissue.

Investigation towards strength properties of ternary blended concrete

  • Imam, Ashhad;Moeeni, Shahzad Asghar;Srivastava, Vikas;Sharma, Keshav K
    • Advances in concrete construction
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    • v.11 no.3
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    • pp.207-217
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    • 2021
  • This study relates to a production of Quaternary Cement Concrete (QCC) prepared by using Micro Silica (MS), Marble Dust (MD) and Rice Husk Ash (RHA), followed by an investigation towards fresh and hardened properties of blended concrete. A total of 39 mixes were cast by incorporating different percentages of MS (6%, 7% and 8%), MD (5%, 10% and 15%) and RHA (5%, 10%, 15% and 20%) as partial replacement of Ordinary Portland Cement. The workability of fresh concrete was maintained in the range of 100±25 mm by adding 0.7% of Super Plasticizer in the mix. Optimum mechanical strength was observed at combination of 8% MS+5% MD+10% RHA. Marble dust replacement from 10 to 15% and Rice husk ash replacements from 15 to 20% depicted a substantial reduction in compressive strength at all ages. Durability parameter with respect to water absorption at 28 days shows an increasing trend as the percentage of blending increases.

New Dioscin-Glycosidase Hydrolyzing Multi-Glycosides of Dioscin from Absidia Strain

  • Fu, Yao Yao;Yu, Hong Shan;Tang, Si Hui;Hu, Xiang Chun;Wang, Yuan Hao;Liu, Bing;Yu, Chen Xu;Jin, Feng Xie
    • Journal of Microbiology and Biotechnology
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    • v.20 no.6
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    • pp.1011-1017
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    • 2010
  • A novel dioscin-glycosidase that specifically hydrolyzes multi-glycosides, such as 3-O-${\alpha}$-L-($1{\to}4$)-rhamnoside, 3-O-${\alpha}$-L-($1{\to}2$)-rhamnoside, 3-O-${\alpha}$-L-($1{\to}4$)-arabinoside, and ${\beta}$-D-glucoside, on diosgenin was isolated from the Absidia sp.d38 strain, purified, and characterized. The molecular mass of the new dioscin-glycosidase is about 55 kDa based on SDS-PAGE. The dioscin-glycosidase gradually hydrolyzes either 3-O-${\alpha}$-L-($1{\to}4$)-Rha or 3-O-${\alpha}$-L-($1{\to}2$)-Rha from dioscin into 3-O-${\alpha}$-L-Rha-${\beta}$-D-Glc-diosgenin, further rapidly hydrolyzes the other ${\alpha}$-L-Rha from 3-O-${\alpha}$-L-Rha-${\beta}$-D-Glc-diosgenin into the main intermediate products of 3-O-${\beta}$-D-Glc-diosgenin, and subsequently hydrolyzes these intermediate products into aglycone as the final product. The enzyme also gradually hydrolyzes 3-O-${\alpha}$-L-($1{\to}4$)-arabinoside, 3-O-${\alpha}$-L-($1{\to}2$)-rhamnoside, and ${\beta}$-D-glucoside from [3-O-${\alpha}$-L-($1{\to}4$)-Ara, 3-O-${\alpha}$-L-($1{\to}4$)-Rha]-${\beta}$-D-Glc-diosgenin into diosgenin as the final product, exhibiting significant differences from previously reported glycosidases. The optimal temperature and pH for the new dioscin-glycosidase is $40^{\circ}C$ and 5.0, respectively. Whereas the activity of the new dioscin-glycosidase was not affected by $Na^+$, $K^+$, and $Mg^{2+}$ ions, it was significantly inhibited by $Cu^{2+}$ and $Hg^{2+}$ ions, and slightly affected by $Ca^{2+}$ ions.

Feasibility of Korean Rice Husk Ash as Admixture for High Strength Concrete: Particle Size Distribution, Chemical Composition and Absorption Capacity Depending on Calcination Temperature and Milling Process (고강도 콘크리트 혼화재로서 국산 왕겨재의 활용 가능성: 소성 온도와 분쇄공정 유무에 따른 입도, 성분 및 흡습 성능)

  • Kwon, Yang-Hee;Hong, Sung-Gul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.4
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    • pp.111-117
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    • 2017
  • This study examined the material properties of Korean rice husk ash (RHA) according to the manufacturing process, and evaluated the feasibility of its use as a new admixture for high strength concrete. For this purpose, its particle size distribution, chemical composition, and microstructure were analyzed under various parameters, such as calcination temperature ($400^{\circ}C$, $650^{\circ}C$, and $900^{\circ}C$) and the inclusion of a milling process. X-ray fluorescence analysis confirmed that the silicon oxide ($SiO_2$) content of RHA was improved to more than 92% with a calcination process at $650^{\circ}C$ or higher. In addition, microstructural analysis showed that the RHA calcined at $650^{\circ}C$ has a porous structure. Because of this, the absorption capacity of the RHA was improved. On the other hand, when the milling process was applied, the porous structure was destroyed; thus, the absorption capacity tended to decrease further. Based on the analysis results, it was concluded that RHA calcined at $650^{\circ}C$ can be used as an admixture for high strength concrete, which possesses functions of both a shrinkage reducing agent and a pozzolanic activator.

A study on performance of the recycle asphalt mixtures using the foamed asphalt method (폼드 아스팔트 공법을 이용한 재활용 아스팔트 혼합물의 성능 연구)

  • Park, Tae-Soon
    • International Journal of Highway Engineering
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    • v.12 no.4
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    • pp.203-209
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    • 2010
  • The base asphalt mixtures that used the waste recycle asphalt correcting from the four different overlay construction sites in Seoul city were made using the foamed asphalt method. The sample mixtures were made in different ratio of the recycle asphalt and new asphalt material and the performance of the mixtures of the different ratio was investigated in the laboratory. The laboratory tests includes the Marshall test, the indirect tensile test, the resilient modulus test, the creep test and the wheel tracking test. The test of the recycle foamed asphalt mixtures(RFA) were compared with the those of the recycle hot mix asphalt(RHA) mixtures. The performance of the RFA is comparable to that of the RHA. On the other hand, the indirect tensile strength of the RFA in dry condition is lower than that of RHA and the indirect tensile strength of the RFA in wet condition is much lower than that of the RHA.

Dopaminergic Regulation of Gonadotropin-II Secretion in Testosterone-treated Precocious Male and Immature Rainbow Trout Oncorhynchus mykiss

  • Kim, Dae-Jung;Aida, Katsumi
    • Animal cells and systems
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    • v.4 no.3
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    • pp.287-292
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    • 2000
  • The present work examined the role of gonadotropin-releasing hormone (GnRH) and dopaminergic drugs on the secretion of maturational gonadotropin (GTH II) in relation to testosterone m treatment. This study provides evidence that the plasma GTH II levels are increased by T treatment in precocious males, but not in the immature animal. In addition, GnRH analogue (GnRHa) alone significantly increased the plasma GTH II secretion in immature rainbow trout treated with T, as well as in T-treated and T-untreated precocious males. However, injection with either dopamine (DA) or domperidone (DOM; DA D2 receptor antagonist) alone did not alter the basal plasma GTH 11 secretion in all experimental groups. The secretion of GTH II in the T-treated precocious males was remarkably influenced by GnRHa or combination of dopaminergic drugs. Notably, the effects of dopaminergic drugs on GnRHa-induced GTH II secretion w8s prolonged by T in precocious males. In T-treated immature animals, GnRHa-induced GTH II secretion was Increased only by a dose DOM (10$\mu$g/g body n) but not by higher dose DOM (100$\mu$/g body wt). In the T-untreated immature rainbow trout, however, plasma GTH 11 secretion was not influenced by the same treatments. Therefore, these results indicate that DA may be acting indirectly by blocking the effect of GnRH on GTH II secretion in vivo. T may act to modulate the relative contribution by the stimulatory (GnRH) and inhibitory (DA) neuroendocrine factors, which would ultimately determine the pattern of GTH II secretion.

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