• Title/Summary/Keyword: bleaching

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Bleaching of Oak Kraft Pulp by O, Eo and C/D Stage (O, Eo 및 C/D단계를 이용한 신갈나무 크라프트펄프표백)

  • 김동호;백기현
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.29 no.3
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    • pp.43-50
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    • 1997
  • The purpose of this study was to decrease pollutants of effluents from KP bleaching. Multistage bleaching that combined with O, Eo, and C/D stage was conducted, after optimum bleaching conditions of O, Eo, and C/D stage were determined. Moreover the properties for bleached pulps and pollution level of bleaching effluent were measured by each standard method. Due to increase on the brightness and delignification of pulps by O, Eo, and C/D stage bleaching. It was possible that bleaching sequences were reduced from five stage to four stage. In addition to, OC/DEoD and OC/DEopD bleaching sequences had higher brightness than CEDED bleaching sequence. The pulps bleached by O and Eo stage had higher in tensile index than conventional bleaching sequences with the similar results in burst and tear index. While each bleaching sequences had little differences, bleaching sequences with Eo stage had higher in physical properties than with Eop stage. The pollution level measured by Chemical Oxygen Demand(COD), Biochemical Oxygen Demand(BOD) and Color of bleaching effluents were much lower in combined bleaching sequences of O, Eo and C/D stage than that of CEDED sequence. Particularly, a pollution index of bleaching effluents generated by C/DEoDEB and OC/DEopDED bleaching sequences were lower than that from the other bleaching sequences.

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Surface Damage and Bleaching Effect according to the Application Type of Home Tooth Bleaching Applicants

  • Tak, Na-Yeoun;Lim, Do-Seon;Lim, Hee-Jung;Jung, Im-Hee
    • Journal of dental hygiene science
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    • v.20 no.4
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    • pp.252-260
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    • 2020
  • Background: In this study, the bleaching effect and surface damage of two types of over-the-counter home tooth bleaching agents were explored using an in vitro study of bleaching agents applied to bovine teeth specimens for 14 days. Methods: Domestic over-the-counter home tooth bleaching agents of gel and patch form that shared common active ingredients and manufacturers were selected and tested. The experiment specimens were made using composite resin with bovine tooth samples and then measured the initial microhardness. Specimens were then divided into a Gel group and a Patch group and underwent bleaching treatment once a day for two weeks for 30 to 60 minutes (recommended) or 7 hours. All specimens were coffee-stained prior to bleaching. The bleaching effect was measured using a spectrophotometer and surface damage was measured using a microhardness meter. Results: The difference in color following the bleaching procedure was positive in both the Gel and Patch group, although there were no statistically significant differences in bleaching effect between groups. There was no significant difference in bleaching effect based on duration. The microhardness test revealed that both the Gel group and the Patch group had surface damage after bleaching. The greatest surface damage was found in the Patch group that had undergone a 7-hour bleaching treatment, although the differences were not statistically significant. Conclusion: The bleaching effect of the home tooth bleaching agent was visible to the naked eye. However, longer applications than recommended did not result in greater bleaching, unlike consumers' expectations, and instead increased the chance of enamel damage. As such, there is a need for consumers to be alert and adhere to recommendations provided by each company.

Studies on Evaluation of Spent Bleaching Clay as a Feed Ingredient in Broiler Chicks (육계의 사료원으로 식용유 정제 폐백토(Spent Bleaching Clay)의 평가에 관한 연구)

  • Jeon, H.Y.;Son, J.H.
    • Korean Journal of Poultry Science
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    • v.34 no.2
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    • pp.99-104
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    • 2007
  • Studies were conducted to evaluate spent bleaching clay as a feed resource. Raw spent bleaching clay from the soybean refining process in a rotary reactor is rich in crude fat (26.0%) and crude ash (68.3%) but low in moisture (5.2%) and crude protein (0.5%). The peroxide value of spent bleaching clay was significantly higher than soybean oil (P<0.05). Also the acid value of spent bleaching clay and soybean oil were 9.72 and 0.001, respectively, it was significantly different(P<0.01). It is possible that the acidification of spent bleaching clay was prevented by artificial method. On the feeding experiment, 2.0 to 4.0% of dietary spent bleaching clay were improve body weight gain, feed intake and feed/ gain. Results indicate that spent bleaching clay may be used at 2.0 to 4.0% for broiler diets without deleterious effects on performance.

Non-chlorine Bleaching of Oak Kraft Pulp by Ozone (오존을 이용한 신갈나무 크라프트펄프의 무염소표백)

  • 김동호;백기현
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.29 no.2
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    • pp.36-45
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    • 1997
  • Newly bleaching sequence using oxygen, ozone and hydrogen peroxide has introduced to avoid pollution hazards from chlorinated organic compounds, because chlorine dioxide substitution bleaching was produced a little chlorinated organic substance. Oxygen-type chemicals replaced for chlorine has attracted much research attention. Bleachability of ozone was improved at low temperature and high pulp consistency. In third bleaching followed OZ bleaching, addition of O2 and NaBH4 in alkali extraction was effective than only alkali extraction. Bleachability of pulps in ozone bleaching(Z) was improved at higher consistency and lower temperature The addition O2 and NaBH4 in alkali extraction after OZ bleaching sequence improved brightness, when compared to those obtained by only alkaline extraction. Pulps bleached by ECF bleaching sequences such as OZEoD and OZEopD was obtained by 90% ISO brightness. The brightness of pulp bleached by TCF sequences with the ozone dosage of 1.6% was approached to target brightness (88~90%ISO). Pulps bleached Z stage combined bleaching sequence was reduced the viscosity to a little greater extent. However, physical properties of pulps was not great different compared to those bleached by conventional bleaching sequences. A pollution index of bleaching effluente by ozone combined bleaching sequences was lower than by conventional bleaching sequence, but somewhat higher than multistage bleaching sequences combined C/D stage.

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Studies on the Multistage Bleaching of Bamboo Chemical Pulps (대나무화학펄프의 다단표백에 관한 연구)

  • 강진하;박성종
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.33 no.4
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    • pp.49-54
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    • 2001
  • This study was carried out to acquire basic data for the bleaching of bamboo chemical pulp. Bamboo chemical pulps (alkaline sulfite (AS)-anthraquinone (AQ) pulp, Kraft pulp) were bleached with two kinds of multistage bleaching methods (CEDED, PDED) using the various kinds of bleaching agents. And, physical properties of bleached pulps were investigated. The conclusions obtained from the results were as follows; The yield of AS-AQ pulp bleached with four-stages bleaching method using the hydrogen peroxide and chlorine dioxide as a bleaching agents was higher than the other bleached pulps. The brightness of kraft pulp bleached with five-stages bleaching method using the chlorine and chlorine dioxide as a bleaching agents was higher than the other bleached pulps. The physical properties of kraft pulp bleached with four-stages bleaching method using the hydrogen peroxide and chlorine dioxide as a bleaching agents was higher than the other bleached pulps.

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A research on the questionnaires about Busan citizen's understanding of the Tooth Bleaching (치아미백에 관한 부산시민의 인식 및 지식도 조사 연구)

  • Lee, Hye-Jin;Jeon, Eun-Suk
    • Journal of Korean society of Dental Hygiene
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    • v.6 no.1
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    • pp.79-91
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    • 2006
  • Through the investigation and analysis for awareness about Tooth Bleaching treatment for general adults, to rethink the real ideas of Tooth Bleaching which adults has already had and to find the method for generalized Tooth Bleaching, this study made a survey about General Awareness and Common sense for Tooth Bleaching and Oral Health Knowledge and Generalization Methods for 570adult citizen in Busan from 1th August to 10th September. The obtained results were as follows 1. Tooth Shade self contentment was found low, self-discontent respondents were 73.5% and self-content respondents were 26.5%. 2. Tooth Bleaching recognition was found high, as for the recognition period, between 2 and 5 years is 65.5% and as for the recognition route, 33.9% were through broadcast medium. 3. General knowledge for Tooth Bleaching was found low as 2.34(1.12) of 5 score and it is similar to ages and occupations(pE0.001, pE0.05). 4. Tooth Bleaching treatment method appears Home Bleaching and In-Office bleaching was 73.5% and 26.5% respectively. The other side medical institution chosen for Tooth Bleaching treatment appears dental hospital or dental clinic and Home bleaching was 75.6% and 12.1% respectively. 5. To generalize the Tooth Bleaching Care, recommendations of oral health care team and oral health education and development of information data also need to be performed.

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A servey on the actual conditions & recognition of tooth bleaching in female college students (치위생과와 비치위생과 학생의 치아미백에 대한 인식도 및 실태조사)

  • Shin, Min-Woo;Ji, Min-Gyeong;Han, Myeong-Suk
    • Journal of Korean society of Dental Hygiene
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    • v.8 no.4
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    • pp.43-53
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    • 2008
  • Some female college students have to recognize and understand the actual conditions of the tooth bleaching, and effective consultation and training to provide basic data for the purpose of investigation. this study made a survey about recognize and understand the actual conditions of the tooth bleaching and oral health knowledge and generalization methods for 649 female college student in Daejeon and Jeonbuk areas during the period between March. 15 and April. 10,2008. The results were as follows: 1. Tooth Status was found low, self-discontent respondents Status 44.2% and average 31.1%, self-contentment were 14.8%. Tooth color was average respondents were 69.8%, yellow 29.0%, White 1.7% (p=0.001, p=0.030). 2. Tooth bleaching experience has not experienced the most the military was 86.4%, to the desired Tooth bleaching for the external beauty 44.2%, confidence of smile time 37.5%. self-discontent 10.7%(p=0.000, p=0.000). 3. Tooth health status satisfaction was dental hygiene students higher than non dental hygiene, and scaling knowledge of the Tooth bleaching effect was non dental hygiene higher than non dental hygiene(p=0.039, p=0.000). 4. General knowledge for Tooth bleaching was found high 96.1%, as for the recognition route, 55.6% were through broadcast medium(p=0.025, p=0.000). 5. Medical institution chosen for Tooth bleaching treatment method appears the most preferred by 79.9% to the dental hospital dental clinic. 6. Important to consider that the choice of Tooth bleaching was Tooth bleaching duration of 37.1% cost 33%, And when Tooth bleaching hoped to be long-lasting. In this research the high recognized of Tooth bleaching treatment, but very low Tooth bleaching experience female college students for the Tooth bleaching had the wrong information. Therefore, Tooth bleaching treatment and counseling that can be used to development and education were required to provide the correct information.

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Sequential Oxidative and Reductive Bleaching of MOW by the Addition of Thiourea (Thiourea 첨가에 의한 MOW의 산화-환원 연속 표백)

  • 김승호;안병준;백기현
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.34 no.3
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    • pp.38-45
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    • 2002
  • The effect of sequential oxidative-reductive bleaching on brightening of the MOWs is investigated. The improvement in brightnesses of MOWs is more effective in conventional PFAS bleaching than in P/T bleaching. There is no difference in the mechanical properties or the bleached pulps between PFAS and P/T sequences. Considering the brightness gains and bleaching chemicals cost, for the MOW A(Initial brightness: 68.3% ISO) containing 5% ONP and 20% colored paper, the P/T bleaching is more economical than the PFAS bleaching. However for MOW B(initial brightness: 59.1% ISO) containing 15% ONP and 35% colored paper, there is no difference in the bleaching efficiency between PFAS and P/T bleaching.

Investigation on the Photooxidation of Pigment in Leaf-Burning Disease of Panax ginseng 1. Phenomenological observation and analysis on the chlorophyll bleaching phenomenon (인삼 엽소병에서 색소의 광산화작용에 관한 연구 1. Chlorophyll bleaching의 현상학적 연구)

  • Yang, Deok-Jo;Yu, Hui-Su;Yun, Jae-Jun
    • Journal of Ginseng Research
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    • v.11 no.2
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    • pp.91-100
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    • 1987
  • This study was investigated and analyzed the side of phenomenological of the chlorophyll bleaching phenomenon on the leaf burning-disease of the Ginseng (Panax ginseng C.A. Meyer) leaf. Red light (660-700 nm) was confirmed as one which induced the bleaching phenomenon and blue light (400-500 nm) did not at all. Temperature as 1 environmental factor had not any influence on chlorophyll bleaching phenomenon at all. Therefore, simple burning (thermal damage) hypothesis was perfectly ruled out by the result of this study. And, low pH accelerated chlorophyll bleaching velocity. A primary factor of chlorophyll bleaching phenomenon may be peculiar structural difference of the Ginseng leaf compared with other plant.

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Knowledge and Satisfaction Status of Tooth Bleaching (치아미백에 대한 지식과 만족도 현황)

  • Jeong, You-Ran;Lee, Ju-Yul
    • The Journal of the Korea Contents Association
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    • v.18 no.10
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    • pp.403-414
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    • 2018
  • The purpose of this study was to investigate the knowledge and satisfaction of tooth bleaching. From June 1st, 2017, 328 patients who visited a dental clinic in Ulsan Metropolitan City for two weeks were asked to do a self - filling questionnaire. As a result of the study, the tooth bleaching satisfaction according to tooth bleaching knowledge was not statistically significant (p<0.05), and the highest(8-10) degree of satisfaction was 3.86 when the knowledge of tooth bleaching was high, and the lowest(0-3) was 3.00. The tooth bleaching satisfaction according to general characteristics was significantly different in age and gender. The score of women were 3.74 and higher than men's 3.11 The tooth bleaching experience and tooth bleaching satisfaction were statistically significant (p <0.05) and professional tooth bleaching (4.41) was higher than OCT bleaching (2.64). Also, when the tooth bleaching was done by the invitation of the hospital, it was higher than the case of experiencing tooth bleaching through media advertising. Therefore, the satisfaction of tooth bleaching is required not only for general characteristics but also for tooth tooth bleaching, and it is influenced by tooth bleaching method and tooth bleaching motivation. These factors may be useful to establish a treatment plan to improve the satisfaction of tooth bleaching.