• Title, Summary, Keyword: Retention

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Liquidity and Mechanical Properties of Concrete by Fluidity Retention Agent Mix Rate Change (유지제 혼입율 변화에 따른 콘크리트의 유동성 및 역학적 특성)

  • Park, Byung-Kwan;Choi, Sung-Yong;Pei, Chang-Chun;No, Dong-Hyun;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.89-92
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    • 2008
  • This research analyzed the basic characteristics of unhardened concrete and the compression strength characteristics of hardened concrete according to liquidity retention agent mix rate change to improve the liquidity fluidity retention performance of high performance concrete, and produced the following results. The moment fluidity retention agent is added according to fluidity retention agent mix rate change, which increased fluidity retention agent mix rate, slump flow decreased, and in the case of slump flow according to the progress time change by the fluidity retention agent mix rates, the more fluidity retention agent mix rate increased, the lower slump flow change rate became. The moment fluidity retention agent is added according to fluidity retention agent mix rate change, fluidity retention agent mix rate increased compared to non-mixture of fluidity retention agent, and the air amount by progress time change by the fluidity retention agent mix rates slightly increased, however target range is still met and unit volume mass is inversely proportional to air amount. Compression strength according to age progress by the fluidity retention agent mix rates was shown to increase slightly with increase in fluidity retention agent mix rate, and yet the difference was not significant.

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Differences in retention of the reduction direction depending on dimensions and design CAD/CAM zirconia abutment for implant (Implant에 사용되는 CAD/CAM 전용 zirconia abutment의 표면적과 디자인에 따른 유지력 차이)

  • Nam, Taeg-Mo;Kim, Han-Gon;Kim, Byung-Sik;Lim, Si-Duk
    • Journal of Technologic Dentistry
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    • v.32 no.4
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    • pp.317-325
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    • 2010
  • Purpose: The aim of this study is to make some basic materials to find retention force difference based on the total height of CAD/CAM zirconia abutment used for implant, retention force difference based on how to regulate the height of the abutment, retention force difference based on the size and retention force difference based on the design group. Methods: The retention force was measured by being pulled at the speed of 1mm/min after being combined with zirconia block and abutment using Temp-BOND of Kerr. The experiment was done at the research lab of OSTEM in Busan by useing UNIVERSAL TESTING MACHINE on March 3rd, 2010. Results: After analysing the total height and the retention force, p-value had minor difference by 0.01 statistically. Namely, 3mm, 4mm, 5mm had the retention force difference and we could see retention force difference on 3mm and 5mm at the post test. After analyzing how to regulate the height and retention force, p-value had minor difference by 0.000 statistically. Namely, 1mm and 2mm had the retention difference and we could see that 1mm and 2mm with the total height had retention difference. After analyzing the retention force based on the size, p-value had minor retention force difference by 0.000 statistically. Namely, 7 different size had retention force difference and we could see the size 21.9mm, 32.9mm, 32.9mm, 38.4mm, 48.9mm and 54.9mm had retention force difference. Conclusion: Namely 9 different design group had retention difference and we could see that 9 design group with 5.6.7.8 design group and 9 design group with 1.2.3.4. design group had retention force.

Evaluation and Application of Retention Aids for Papermaking System Closure

  • Lee, Hak-Lae;Sung, Yong-Joo;Youn, Hye-Jung;Kim, Yong-Sik;Oh, Jong-Ik
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.30 no.4
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    • pp.11-17
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    • 1998
  • Reducing the effluent discharge from a paper mill is urgently needed due to tightening environmental regulations and economic reasons. For a paper mill to respond to system closure it is required to adopt the best practical retention system that enables the mill to improve fines retention and drainage. In this study, effects of various retention agents on fines retention, drainage and formation were examined using linerboard stock in the laboratory. Among the retention aids tested, high molecular weight cationic polyacrylamides showed good efficiency both in retention and drainage. On the other hand, high charge density, low molecular weight polymeric retention aids showed little improvement both in retention and drainage. The best retention system selected from the laboratory experiment was applied on a paper machine producing linerboard to evaluate its effect on papermaking system closure.

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Controllability of White Pitch and Compatibility of Micropolymer on PEO/Cofactor Retention System and PAM/Bentonite Retention System (PEO/cofactor 보류 시스템과 PAM/bentonite 보류 시스템에서의 micropolymer 상용성과 백색 점착성 이물질 제어 효과)

  • Jung, Chul-Hun;Lee, Jin-Ho;Park, Jong-Moon
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.44 no.6
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    • pp.43-49
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    • 2012
  • In this work, the non-ionic polyethylene oxide(PEO)/phenolic formaldehyde resin(PFR) retention system, which was less affected by furnish charge, was analyzed for possibility and effectiveness when using recycled stock. When the micropolymer was added at the PEO/PFR retention system and the PAM/bentonite retention system, performance of retention and drainage was improved. When the cationic micropolymer was added on the PEO/PFR retention system, the highest retention was achieved. The Polyacrylamide(PAM)/bentonite system induced flocculation of white pitch by electrostatic flocculation. On the other hand, the non-ionic PEO/PFR retention system induced less flocculation of white pitch than the PAM/bentonite retention system.

Application of PEO/Cofactor System on Papermaking Process for Recycled Fibers (재생 지료 공정에서의 PEO/cofactor 보류 시스템의 적용)

  • Jung, Chul-Hun;Lee, Jin-Ho;Kil, Jung-Ha;Park, Jong-Moon
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.44 no.4
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    • pp.25-31
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    • 2012
  • Ionic trash in furnish decreases retention and drainage performance of the microparticle retention system using recycled fibers in closed papermaking system. Two retention systems, such as the microparticle system and the PEO/cofactor system, were compared and analyzed to improve retention. The PEO/cofactor system achieved similar retention performance at low addition level as the microparticle system. Optimum ratio of PEO/cofactor dual polymer system was 1:10. Ash retention was increased when using the fixing agent. As the TMP ratio increased, the PEO/cofactor system was more efficient in retention and drainage than the other system. The high molecular weight and non-ionic polymer retention system had less effect on flocculation hindrance than the traditional electrostatic retention system.

Mineral Retention in Young Broiler Chicks Fed Diets Based on Wheat, Sorghum or Maize

  • Thomas, D.V.;Ravindran, V.
    • Asian-Australasian Journal of Animal Sciences
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    • v.23 no.1
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    • pp.68-73
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    • 2010
  • The aim of the present study was to determine the changes in mineral retention of broiler chicks fed diets based on wheat, sorghum or maize during the first two weeks post-hatch. The retention of five major minerals (calcium, phosphorus, potassium, sodium and magnesium) and four trace minerals (iron, manganese, zinc and copper) was determined on days 3, 5, 7, 9 and 14 of age. The retention coefficients of individual minerals differed widely and the retention coefficients of major minerals were found to be considerably higher than those of trace minerals. Age effects were significant (p<0.05) for all minerals. In general, mineral retention coefficients were highest at day 3, declined to day 7, and remained unchanged to day 14. Decline in mineral retention with age was similar on all three diets. The cereal effect was significant (p<0.05) for several minerals, with a general tendency for the sorghum-based diet to have greater retention than maize- or wheat-based diets.

A CLINICAL STUDY ON THE RETENTION OF MAXILLARY COMPLETE DENTURE WITH DIFFERENT DENTURE BASE MATERIALS (의치상의 종류에 따른 상악 의치상의 유지력에 관한 임상적 연구)

  • Lee Jong-Hyuk;Lim Ju-Hwan;Cho In-Ho
    • The Journal of Korean Academy of Prosthodontics
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    • v.39 no.1
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    • pp.58-70
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    • 2001
  • For the successful treatment of complete denture, obtaining a good retention is essential. There are lots of factors affecting denture retention. Denture material, one of those factors affecting denture retention, was the subject of this study, and internal surface treatment also considered for the method of enhancing denture retention. Two resin(Lucitone $199^{(R)}$(heat cured resin) Vertex $CP^{(R)}$(self cured resin)) and two metal($Biosil^{(R)}$(Co-Cr alloy), $Vitallium^{(R)}$(Co-Cr alloy)) denture base materials were used for making test denture base. Newly developed device was used for measuring denture retention. After the retention was measured. We treated internal surface of test denture base with $50{\mu}m\;Al_2O_3$ powder, under 90psi, for 1 minute. Then the retention was measured again. The result was analyzed with K-S test, one-way ANOVA test and independent t-test to deter mine the significant differences as the 95% level of confidence. The results are as follows : In cases of without internal surface treatment, the retention was increased in order of $Vitallium^{(R)},\;Biosil^{(R)},\;Vertex CP^{(R)}$ and Lucitone $199^{(R)}$. Except between Vertex $CP^{(R)}$ and $Biosil^{(R)}$, retention of the other materials was significantly different (p<0.05). After the treatment of internal surface, the retention was increased in order of $Vitallium^{(R)},\;Biosil^{(R)},\;Lucno\;199^{(R)},\;Vertex\;CP^{(R)}$. Except between Lucitone $199^{(R)}$ and Vertex $CP^{(R)}$, $Vitallium^{(R)}$ and $Biosil^{(R)}$ the retention of remaining groups was significantly different each other (p<0.05). In the matter of each material, after the internal surface treatment the retention was increased with Vertex $CP^{(R)},\;Biosil^{(R)}\;and\;Vitallium^{(R)}$ and the value of differences were statistically significant. When we compare the retention of resin and metal denture base, the retention of both denture bases increased significantly with internal surface treatment, and resin denture base showed better retention. As the results show, selecting denture base material could be an important choice of complete denture treatment. To increase denture retention, internal surface treatment can be considered as a possible method.

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Retention Performance of Nanocoated GCC with Positive Charge (양이온성으로 표면 개질된 nanocoated GCC의 보류 성능)

  • Lee, Jegon;Sim, Kyujeong;Lee, Hak Lae;Youn, Hye Jung
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.45 no.5
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    • pp.14-22
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    • 2013
  • In this study, we investigated retention characteristics of nanocoated GCC that was positively modified by Layer-by-Layer (LbL) multilayering process. Three layers were formed onto GCC particles with poly-DADMAC/PSS/poly-DADMAC (PD3) and C-starch/A-PAM/C-starch (CS3) systems, respectively. Untreated GCC, PD3 GCC (strongly positive charge) and CS3 GCC (weekly positive charge) were retained on pulp fibers under single retention system or microparticle retention system conditions. In single retention system, PD3 particles were not affected by cationic retention aid due to their strong positive charge, whereas CS3 particles reacted with cationic retention aid due to anionic sites on the surface of the weekly positive particles. In a microparticle retention system, positively modified GCC (PD3 and CS3) showed higher retention level than untreated GCC at the same dosage of retention aid. The cationic surface of GCC particles were more reacted with bentonite so the deposition onto pulp fibers was improved. In addition, the retention level of nanocoated GCC was increased with maintaining good formation.

EFFECTS OF DIETARY SILICIC ACID AND CADMIUM ON SHORT-TERM MINERAL BALANCES IN SHEEP

  • Bruce, L.B.
    • Asian-Australasian Journal of Animal Sciences
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    • v.2 no.4
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    • pp.579-582
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    • 1989
  • Previous experiments have shown that aqueous sodium silicate ingested in drinking water may modify the gastrointestinal uptake and(or) tissue retention of certain trace elements, including heavy metals. The present experiment tested, with a mineral balance trial using sheep, the hypothesis that dietary silicic acid could modify uptake, retention and(or) biological effects of dietary Cd. Twenty-four wethers were fed a fibrous diet of ground alfalfa hay and cottonseed hulls to which either 0 or 150 ppm Cd was added as $CdCl_2$ and 0, .5 or 1% silicic acid (as dry matter of the diet). Body weight, feed intake, excretion of urine (volume) and feces (weight), digestibility of dry and organic matter, retention of nitrogen, and packed cell volumes of blood were not affected by either Cd or silicic acid (P<.10). Cadmium decreased (P<.05) Ca retention and increased (P<.01) Mg retention. Silicic acid decreased (P<.05) K retention. Silicic acid failed (P<.01) to modify the retention of added dietary Cd. Body retention of K, Mn and Ni in response to silicic acid varied with Cd levels. If Cd is interfering with mineral retention, silicic acid may be effective in preventing this interference.

Affecting Factors of New Nurse's Intention to Retention in Hospitals (신규간호사의 재직의도 영향요인)

  • Son, Haeng-Mi;Lee, Eun Hee;Cho, Kyung Sook
    • Journal of muscle and joint health
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    • v.24 no.3
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    • pp.205-216
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    • 2017
  • Purpose: The purpose of this study is to investigate relationship among intention to retention, role conflicts, psychosocial job conditions and job satisfaction of new nurses, and identify affecting factors for intention to retention. Methods: Data were collected from 136 new nurses who were graduated at 2016 and working now in general hospitals by self-reported questionnaire. The relationship among variables were analyzed with Pearson's coefficient correlation and affecting factors for intention to retention were identified by using multiple linear regression analysis. Results: The mean score of intention to retention was $2.63{\pm}0.28$. Intention to retention was significantly different by the working ward, hope period for work, and reason for retention. Intention to retention had positive relationships with work organization and job contents, and job satisfaction, but negative relationships with frequency of role conflict, demands at work. Job satisfaction and meaning of work identified as influencing factors inn intention to retention. Conclusion: It is needed a positive hospital environment to improve adaptation in clinical nursing practice and to emphasize professionalism including value of nursing and meaning of nurses' work for new nurses.