• Title/Summary/Keyword: Mass changes

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A Numerical Study on the Convective Mass Transfer in Horizontal Rectangular Enclosures (수평 직사각 밀폐공간에서의 대류물질전달에 관한 수직적 연구)

  • 배대석
    • Journal of Advanced Marine Engineering and Technology
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    • v.22 no.3
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    • pp.294-302
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    • 1998
  • The charateristics of the convective mass transfer in horizontal rectangular enclosure with horizontal concentration gradients are analyzed. The effect of Grashof number(Gr) and aspect ratio(L/H) is investigated numerically using the control-volume method. Numerical results are obtained for Grashof numbers between $10^4$ and $10^6$ aspect ratios from 1 to 100 and results are compared with existing andlytical results. It is found that there exists a well defined aspect ratio for which the mean Sherwood number is maximum and the core flow changes from parallel to non-parallel at $Gr^2{Sc^2}(A^{-3}}{\geq}{10^5}$ and in the Ralongrightarrow0 regime the numerical results agreed very well with correlation derived from analytical results.

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Development of the Character Constancy Concept: Self and Others (아동의 항상성개념 발달에 관한 연구 - 자신 및 타인의 개인특성을 중심으로 -)

  • Kim, Chang Ha
    • Korean Journal of Child Studies
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    • v.8 no.1
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    • pp.15-29
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    • 1987
  • The purpose of the present research was to investigate (I) the acquisition of character constancy of self and others as a function of age; (2) the pattern of acquisition of character constancy, and (3) the relationships between character constancy and conservation of number and mass. The subjects of this study were 160 children, 20 boys and 20 girls at each grade level, kindergarter through grade 3. The Character Constancy Tasks devised bi Rotenberg (1982) and conservation task of number and mass were administered to each child. Chi square, Guttman Scale analysis and Pearson's Correlation were used for the statistical analysis of data. The findings showed that there was increase with age in character constancy of others and of sell in that there was increase with age in children's belief that the characteristics of another person are stable across time and consistent despite changes in a person's appearance. Character constancy of others and of self were acquired in the developmental stages of identity, stability, and consistency. Character constancy of others and self correlated with the conservation of number and mass.

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Performance Prediction of a Gas Turbine Using CO2 as Working Fluid (CO2를 작동유체로 하는 가스터빈의 성능예측)

  • Yang, Hyun-Jun;Kang, Do-Won;Lee, Jong-Jun;Kim, Tong-Seop
    • The KSFM Journal of Fluid Machinery
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    • v.14 no.2
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    • pp.41-46
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    • 2011
  • This study investigated the changes in performance and operating characteristics of an F-class gas turbine according to the change of working fluid from air to carbon dioxide. The revised gas turbine is the topping cycle of the semi-closed oxy-fuel combustion combined cycle. With the same turbine inlet temperature, the $CO_2$ gas turbine is expected to produce about 85% more power. The main contributor is the greater compressor mass flow and the added oxygen flow for the combustion. Compressor pressure ratio increases about 50%. However, the gas turbine efficiency reduces about 10 %. Modulation of inlet guide vane to reduce the compressor inlet mass flow, the major purpose of which is to reduce the compressor inlet Mach number, was also performed.

Growth Hormone Therapy in Adults with Prader-Willi Syndrome

  • Cho, Sung Yoon
    • Journal of mucopolysaccharidosis and rare diseases
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    • v.1 no.2
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    • pp.49-53
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    • 2015
  • Prader-Willi syndrome (PWS) is a complex multisystem genetic disorder characterized by hypothalamic-pituitary dysfunction. Many features of PWS indicate a deficiency in growth hormone (GH) production, and these findings provide a rationale for GH therapy in PWS. It is possible that rhGH therapy could have beneficial effects in adults with PWS, similar to those in adults with GH deficiency (GHD) of non-syndromic cause. However, there is a paucity of data on the use of GH in adults with PWS. Here, the previous studies about efficacy and safety of rhGH therapy in PWS adults are summarized. Briefly, rhGH therapy in PWS adults may improve body composition, leading to increased lean body mass and decreased fat mass, as well as decreased subcutaneous and visceral adiposity without overall changes in body mass index. There may be at least transient deterioration in glucose homoeostasis in some PWS patients on rhGH therapy, which requires further study. In addition, clinical care guidelines for rhGH therapy in adults with PWS were suggested.

The Sensitivity Analysis for Structure Modification using Partial Differentiation (구조물의 동특성 개선을 위한 모드 매개변수의 민감도 해석)

  • Lee, Hae-Jin;Abu, Aminudin;Lee, Jung-Youn;Oh, Jae-Eung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.453-457
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    • 2006
  • This study predicts the modified structure of eigenvectors and eigenvalues due to the changes in the mass and the stiffness of the structure. The sensitivity method of natural frequency using partial differential are derived with respect to the physical parameter to calculate the structure modification. The method are applied to the 3 degree of freedom???slumped mass model by modeling the mass and stiffness, and then applies the method to a real crankshaft system. The position, direction of parameter change and modified value were predicted for modification. Finally the predicted value is used to investigate the magnitude of vibration and we found that the effect of modification results to reduce the level of magnitude vibration is satisfactory.

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Effect of TiC Content on Oxidation Behavior of Sintered WC-TiC-TaC Alloys

  • Tanaka, Hiroki;Mouri, Shigeki;Nakahara, Kenji;Sano, Hideaki;Zheng, Guo Bin;Uchiyama, Yasuo
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.352-353
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    • 2006
  • The effect of TiC content on oxidation behavior of the sintered WC-TiC-TaC alloys with 2 mass% TaC and different TiC amounts of 3-45 mass% was investigated through oxidation tests in air at 973K. As a result of the tests, it was revealed that with increasing TiC content in the alloys, mass changes caused by oxidation and thickness of the scale decreased. Thus, it is considered that the main component of the scales changed gradually from $WO_3$ to $TiO_2$ with increasing TiC content in the alloys, and oxygen diffusion through the scale to the alloys was inhibited gradually.

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Effects of Electrical and Acoustical Variations for Loudspeaker due to Fabrication Processes (조립과정이 스피커의 전기 및 음향특성에 미치는 영향)

  • Park, Seok-Tae
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.11a
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    • pp.155-159
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    • 2004
  • In this paper, it was analyzed the characteristics of electrical and acoustical variations for loudspeaker due to fabrication processes. First, mass of each components of loudspeaker was measured by electric precision scale and performed statistical analysis. Second. Thiele-Small parameters of sample loudspeakers produced by unskilled students were identified by known mass parameter identification method using electrical impedance method and investigated on the variations of each parameter. Electrical impedance tests and acoustic frequency responses were measured on sample loudspeakers and variations were examined to grasp relationship between components variation and fabrication processes. Main factors to effect the changes of electrical impedance were concluded by fabrication processes errors not by components of loudspeaker.

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Investigation on Lipopolysaccharide Activated Microglia by Phosphoproteomics and Phosphoinositide Lipidomics

  • Kim, Young Jun;Kim, Hackyoung;Noh, Kwangmo
    • Mass Spectrometry Letters
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    • v.5 no.3
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    • pp.70-78
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    • 2014
  • Microglia are the confined immune cells of the central nervous system (CNS). In response to injury or infection, microglia readily become activated and release proinflammatory mediators that are believed to contribute to microglia-mediated neurodegeneration. In the present study, inflammation was induced in the immortalized murine microglial cell line BV-2 by lipopolysaccharide (LPS) treatment. We firstly performed phosphoproteomics analysis and phosphoinositide lipidomics analysis with LPS activated microglia in order to compare phosphorylation patterns in active and inactive microglia and to detect the pattern of changes in phosphoinositide regulation upon activation of microglia. Mass spectrometry analysis of the phosphoproteome of the LPS treatment group compared to that of the untreated control group revealed a notable increase in the diversity of cellular phosphorylation upon LPS treatment. Additionally, a lipidomics analysis detected significant increases in the amounts of phosphoinositide species in the LPS treatment. This investigation could provide an insight for understanding molecular mechanisms underlying microglia-mediated neurodegenerative diseases.

Effects of Complex Exercise Program on Body Composition of Dormitory-type Middle School Students (복합운동프로그램이 기숙형 중학생의 신체조성에 미치는 영향)

  • Lee, Hyojeong;Lee, Boram;Lee, Eunsun;Yu, seungju;Lee, Yeonhwa;Lee, Jieun;Han, Dongguk
    • Journal of The Korean Society of Integrative Medicine
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    • v.3 no.2
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    • pp.17-28
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    • 2015
  • Purpose: The purpose of this study was intended to investigate the effect on the body composition of the dormitory-type middle school students by implementing the complexed exercise program. Method: As subjects of the study, the dormitory-type middle school students in Chungbuk, divided into 2 grade experimental group(N=46), 3 grade control group(N=49). Group-specific arbitration method, was applied to complexed exercise program (experimental group) and running group (control group). Each training courses 30 minutes 5times weekly, examined the changes in body composition to examine a total of 6-week course effectively. Result: The results were compared with change of Height, Muscle mass, Fat mass, Lean body mass and BMI. Experimental group were significant(p<.05) compared to the control group. Height, Weight, Muscle mass, Fat mass, and BMI of control group wasn't significant(p>.05). Also there were significant difference(p<.05) between groups on Height, Muscle mass, Fat mass and Lean body mass post-test measure. Conclusion: Looking in total from the above results, it is suggested that it is possible to complexed exercise program 6 weeks improves body composition of the dormitory-type middle school students. Therefore, it is possible that the application of complexed exercise program is to effective in improvement of body composition of the dormitory-type middle school students.

Review on the Correlation between Bone Mass, Skinfold Thickness and the Volume of Urine collagen Peptide in Postmenopausal Women (폐경 후 여성의 골량과 피부두겹두께 및 뇨 콜라겐펩타이드 양의 관련성에 대한 고찰)

  • Park, Mi-Jung
    • Journal of Korean Biological Nursing Science
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    • v.3 no.2
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    • pp.91-103
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    • 2001
  • The bone is composed of the bone matrix of collagen and hydroxyapatite, the mixture of calcium and phosphours. The bone tissue is considered to the special connective tissue that possesses extracellular matrix made by collagen fiber deposited with mineral complex. In order to maintain bone mass measured by the sum of bone matrix and hydroxyapatite, bone resorption by osteoclast during lifetime and bone remodeling to form bone by osteoblast in its resorption region repeat continuously. The osteoblast has a mesodermic fetal origin like fibroblast for the formation of form tissues. Two cells express identical genes and synthesize the identical collagen type I as the major component of the formation of bone matrix and skin. Therefore, it is considered that the decrease of skinfold thickness and the decrease of bone mass related to the age, the change of two tissues composed of collagen type I is caused by the same genetic mechanism. The decrease of bone mass is caused by the change of the amount and structure of bone matrix by several factors and the amount of minerals deposited on bone matrix. Especially, in case of female, the deficiency of estrogen by menopause makes these changes rapidly increased. The decrease of bone mass and skinfold thickness is due to the decrease of the amount of collagen and its structural change the common component of bone tissue and skin tissue. Therefore, the relationship of the amount of cross-linked peptide N-telopeptide, collagen metabolite which excretes as urine. Based upon the proved results about the significant relationship of bone mass, the amount of bone collagen, the amount of skin collagen and skinfold thickness, the bone mass may be expected through a facile determination of skinfold thickness.

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