• 제목/요약/키워드: physical separation

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Isotopic Hydrograph Separation Using Artificial Rain-on-snow Experiments and Its Implications by Each Tracer (인공강우실험을 이용한 동위원소수문분리 및 각각의 추적자에 따른 의미)

  • Lee, Jeonghoon
    • Ocean and Polar Research
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    • v.38 no.4
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    • pp.331-338
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    • 2016
  • Many studies using tracers have been conducted to understand a physical process in a system. Rain-on-snow could accelerate snowmelt processes, which influences the hydrological process in both temperate and polar regions. Hydrological and ecological conditions will be affected by the amount and timing of discharge reaching the bottom of a snowpack. The discharge consists of the rain-on-snow, pore water penetrating into the snowpack and natural meltwater. In this study, after a rain-on-snow experiment, we conducted an isotopic hydrograph separation to distinguish rainwater and pore water from meltwater. Using the isotopic data of snow and meltwater from Lee et al. (2010), two components were separated based on the assumption that rainwater and pore water are new water and natural meltwater is old water. After the second rain-on-snow experiment, the maximum contributions of rainwater and pore water reached up to 69% of the discharge and then decreased. During the study period, the measured total discharge was 4153 L and 40% (based on hydrogen isotope) of rainwater and pore water was calculated in the discharge, which is not consistent with what Lee et al. (2016) calculated using chemical separation (63%). This inconsistency can be explained by how an end-member was defined in both approaches. The contributions of artificial rainonsnow and pore water to melwater discharge range between the two methods. This study will suggest a mixing calculation from isotopic compositions of the Southern Ocean.

Particle Separation and Flotation Efficiency by Dissolved Carbon Dioxide Flotation Process (용존이산화탄소부상(DCF) 공정의 입자분리 특성과 부상효율)

  • Kwak, Dong-Heui;Kim, Seong-Jin;Jung, Heung-Jo;Park, Yang-Kyun;Yoo, Young-Hoon;Lee, Young-Dong
    • Journal of Korean Society of Water and Wastewater
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    • v.25 no.4
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    • pp.471-478
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    • 2011
  • A series of laboratory experiments carried out to investigate the particle separation efficiency and flotation characteristics using $CO_2$ bubbles. The primary objective of this study was to find out the feasibility of $CO_2$ bubbles as an applicable unit of flotation process in tap-water and wastewater treatment plant. The fundamental measurements were conducted to characterize the $CO_2$ bubble from the physical viewpoint in water including bubble size distribution and rising velocity under various operational conditions. In addition, the removal efficiency of solid was experimented using the lab scale plant applied $CO_2$ bubbles, namely the dissolved carbon dioxide flotation (DCF) process. The DCF process using carbon dioxide bubble, which is an advantage as the decrease and the reuse of Green-House gas, can be a promising technology as an water treatment process. On the other hand, the further research to decrease the bubble size distribution of $CO_2$ is required to enhance the particle separation efficiency.

THE PROCESS OF PLAYTHERAPY OF A CHILD WITH ELECTIVE MUTISM (선택적 함구증을 보인 6세아동의 놀이치료)

  • Kwak, Young-Sook
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.3 no.1
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    • pp.138-146
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    • 1992
  • The study presented the experience of playtherapy of a 6-yr old girl with elective mutism and attempted to understand her psychopathology and formulated her psychodynamic which was expressed though the therapeutic process of playtherapy in the viewpoint of developmental model. Therapist's attitude was nondirective and supportive. Main theme of her play, fantasy and art was separation anxiety and abandonment fear as the result of continued psychic traumas such as separation from her grandmother and physical abuse by her father and mother etc. So she couldn't achieve developmental tasks such as autonomy and separation individuation and became generally inhibited and selectively mute. The process of play therapy was summarized and coceptualized as her successful progress through sequential developmental phases within the therapeutic relation ship. By reexperiencing this developmental process, she could accomplish her autonomy and separation individuation and developed to oedipal stage and successfully resolve oedipal conflict.

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Separation of VOCs from Air through Composite Membranes Prepared by Plasma Polymerization of Hexamethyldisiioxane (Hexamethyldisiioxane의 플라즈마 중합에 의하여 제조된 복합막을 통한 공기중의 휘발성 유기물질의 분리에 관한 연구)

  • 류동현;오세중;손우익;구자경
    • Proceedings of the Membrane Society of Korea Conference
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    • 1998.10a
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    • pp.63-65
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    • 1998
  • 1. Introduction : Atmospheric discharge of VOC-contaminated streams in chemical plants and air streams from chemical processes poses a serious environmental problem and entails large financial losses. Such emissions may be reduced by i) adsorption process, ii) absorption process and iii) incineration process. These processes only forbids the air pollutions. Throughout the recent decade, another technique-membrane process has emerged. The separation and recovery of organic vapors by membrane process may have great economic potential. Most of the published research works on the separation of organic vapors from air were performed using silicon rubber membranes. However, it is very difficult to fabricate very thin membranes with less than 1 $u m thickness. Plasma polymerization could be a good technique to generate a thin polymer film. The objective of this work is to find out the optimum condition of plasma polymerization for producing VOC separation membrane. For the objective, composite membranes are prepared through plasma polymerization of hexamethyldisiloxane onto porous substrates under different conditions. The membrane is then subjected to the permeation of permanent gases and VOCs to find the correlations between the physical properties of the penetrant and permeability and selectivity.

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A Study of Job Satisfaction and Related Factors of the National Hospital Nurses (국립병원 간호사의 직무만족과 관련요인 연구)

  • Suh Gil-Hee;Kim Ok-Hee
    • Journal of Korean Public Health Nursing
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    • v.7 no.2
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    • pp.53-66
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    • 1993
  • By this time, a few of previous studies of factors related to separation from their jobs and job satisfaction only have dealt with the separation rate. the cause of separation and related factors that induce job satisfaction and incentive factors, the actualities of morale some suggestions for reduction of the separation rate. This study is attempted to determine factors that have effect on job satisfaction of national hospital nurses. and to proide information and materials for the development of the administration of nursing through the appreciation of factors influencing on job satisfaction between isolated ward nurses and general ward nurses working at national hospitals. 185 nurses of national hospitals responsed th this study, and were divided into two groups. Group 1: 57 nurses working at isolated wards for tuberculosis patients and Group 2 : 128 nurses at general wards. Relevant data were collected from August, 5, 1992 through August 20, 1992. The questionnaire consisted of 8 genalized items and 4 items concerning job satisfaction. The collected data were processed with SPSS, and the relationship among vaviables was analyzed by means of $X^2-test$, Pearson Correlation, Multiple Regression. The results of this study are as follows: 1. There is no significant difference between two groups in terms of generalized items. Age distributions show $44.3\%$ under the category of less than 34. and $55.7\%$ under the category more than 35, $19.3%$ was single and $74.6\%$ was married respectively. 2. $79.4\%$ of the nurses have the desire to have in-service education under the satisfactory physical environments such as welfare system, accommodating structures and facilities, instruments or management systems of the hospital, but under the category of unsatisfactory circumstances, $60.3\%$ have the intention of having in- service education. The concern in terms of in-service education shows statistically significant difference between two groups $(X^2=8.85,\;p<0. 05)$. This result accepts the hypothesis that good physical environments could intensify interests in service education. 3. The extent of satisfaction related to psychological environments is heightend according to good physical environments. In result, the hypothesis that the extent of satisfaction in terms of physical environments could raise satisfaction about psychological environment is accepted. 4. In the light of the extent of satisfaction about physical environments, $33.3\%$ of isolated ward nurses are satisfied with physical environments, but only $11.7\%$ of general ward nurses are satisfied. $(X^2=10.88,\; p<0.01)$. This result shows that the satisfaction degree about phusicalenvironments of isolated war nurses was higher than that of general ward nurses in spite of high physical and psychological risks due to exposure to infection. Consequently. the hypothesis was rejected that the satisfaction degree about physical environments would be lower in isolated ward nurses than in general ward nurses. 5. The fact that $87.7%$ of isolated ward nurses took interest in service education and $53.19\%$ of general ward nurses took interest in service education demonstrats that isolated ward nurse have more interest in service education than gerneral ward nurses. The result shows that the hypothesis is accepted that isolated ward nurses would have mor interests in service education than general ward nurses. 6. In the extent of satisfaction about physical environments such as morale human relationship promotion, there is no significant difference between two groups in terms of statistics. The hypothesis is rejected that satisfaction about psychologic environments would be high in isolated ward nurses than in general ward nurses. In conclusion. factors influencing on job satisfaction are considered to have effect on. another, and also interdisciplinary amelioration of factors accompanied with systematic inter cooperative investigation is necessary.

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A Refining of Natural Diatomite and Synthesis of SiC Powder (규조토 정제 및 탄화규소 분말합성)

  • Pai, Chul-Hoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.3
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    • pp.312-319
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    • 2017
  • For high value-added applications of natural blue diatomite, the physical refining process and synthesis of SiC from refined diatomite were investigated. Approximately 30 percent Fe ($Fe_2O_3$) in raw blue diatomite was removed by a particle sieve separation process; the Fe composition for 325 mesh down powder was approximately 2 percent. Although a wet and/or dry magnetic separation process had some influence on the separation and/or refining of Fe composition, the Fe composition in the non-magnetic by-product was approximately 2 percent. Water leaching separation was effective in removing the Fe composition; approximately 40 percent of the Fe in raw blue diatomite was removed. The synthesis of ${\beta}$-SiC by a carbothermal reduction of the $SiO_2$ in the refined diatomite using carbon (graphite, carbon black), the effects of an acid-treatment on removing the Fe, and the specific surface area for the synthesized powder were also investigated. The impurities were mostly eliminated and the specific surface area was increased to $52.5m^2/g$.

Anisotropic Acorn-like Particle Fabrication Via a Dynamic Phase Separation Method (동적 상분리법을 이용한 이방성 도토리형상 입자 제조)

  • Park, Chul Ho;Baek, Il-hyun
    • Membrane Journal
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    • v.29 no.1
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    • pp.61-65
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    • 2019
  • Anisotropic particles have been issued in various fields due to their unique physical properties. Herein, a novel dynamic phase separation method (DPS) is introduced to fabricate anisotropic acorn-like nanoparticles. DPS consists of two dynamic conditions; solvent evaporation and nonsolvent induced precipitation. The bottom layer is controlled by feeding the water as a non-solvent diluent, and the phase separation of the upper layer relies on the diffusion and evaporation of a volatile good solvent. At this condition, the acorn-like particles were fabricated. Under a closed box filled with water (spontaneous phase separation), monodisperse polystyrene (PS) particles were synthesized. At the coexistence between DPS and spontaneous phase separation, the sizes of cap and particle were changed. Also, the volume of PS solutions influences on the particle shape. Since the unique structures could be utilized into various applications, if advanced techniques such as membrane-based controlled water feeding is developed, monodisperse acorn-like particles could be tuned.

A Comparison of Three Low Back Disability Questionnaires With Rasch Analysis (라쉬분석을 이용한 세 가지 요통 장애 설문지의 비교)

  • Kim, Gyoung-Mo;Park, So-Yeon;Yi, Chung-Hwi
    • Physical Therapy Korea
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    • v.18 no.3
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    • pp.94-102
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    • 2011
  • The purpose of this study was to review existing assessment tools for patients with low back pain and improve them through combination. A total of 314 patients with low back pain participated. Their condition was assessed using the Oswestry Disability Questionnaire (ODQ), the Quebec Back Pain Disability Scale (QBPD), and the Back Pain Functional Scale (BPFS). Rasch analysis was applied to identify inappropriate items, item difficulties, and the separation index. In this study, the 'sex life' item of the ODQ (10 items) and the 'sleeping' item of the BPFS (12 items) showed misfit statistics, whereas all items of the QBPD (20 items) were appropriate. After combining the ODQ, QBPD and BPFS, Rasch analysis was applied. The 'pain intensity', and the 'sex life' item of the ODQ and the 'throw a ball' item of QBPD showed misfit statistics. These 3 items were retained for further analysis. The remaining 42 combined ODQ-QBPD-BPFS items were arranged according to difficulty. For all subjects, the most difficult item was 'pain intensity', whereas the easiest was 'take food out of the refrigerator'. As the separation index of 42 combined ODQ-QBPD-BPFS was higher than that of the three questionnaires separately, difficulty of items varied with some need for rearrangement. The results of this study confirmed the possibility and need for a new back pain disability assessment tool, and produced one. Further study is needed to refine the questionnaire in consideration of psychosocial and occupational factors.