• 제목/요약/키워드: Size Distribution

검색결과 7,760건 처리시간 0.037초

Raindrop Size Distribution Over Northeastern Coast of Brazil

  • Tenorio Ricardo Sarmento;Kwon Byung-Hyuk;Silva Moraes Marcia Cristina da
    • Journal of information and communication convergence engineering
    • /
    • 제4권1호
    • /
    • pp.46-52
    • /
    • 2006
  • Precipitation measurement with ground-based radar needs an information of the raindrop size distribution (RSD) characteristics. A 10-month dataset was collected in tropical Atlantic coastal zone of northeastern Brazil where the weather radar was installed. The number of drop was mainly recorded in 300 - 500 drop $mm^{-3}$, of which the maximum was registered around 1.1 mm drop diameter.

The Effect of the Acid Precipitate Conditions on the Size Distribution of Molybdenum Trioxide Particle

  • Tang, Jun-Li
    • 한국분말야금학회:학술대회논문집
    • /
    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
    • /
    • pp.171-172
    • /
    • 2006
  • The effect of the preparation factors, such as the feeding mode and rate of raw materials, the reaction temperature and the surfactant on the size distribution of molybdenum trioxide particle were investigated by orthogonal test. The optimum conditions for the preparation of $MoO_3$ precursors are as following; opposite feeding fast, reaction temperature of $60^{\circ}C$ and adding dispersant.

  • PDF

Asymptotic Distribution in Estimating a Population Size

  • Choi, Ki-Heon
    • Journal of the Korean Data and Information Science Society
    • /
    • 제10권2호
    • /
    • pp.313-318
    • /
    • 1999
  • Suppose that there is a population of hidden objects of which the total number N is unknown. From such data, we derive an asymptotic distribution.

  • PDF

분쇄방법에 따른 고려홍삼분말의 품질특성 (Quality Characteristics of Korean Red Ginseng Powder with Different Milling Methods)

  • 서창훈;이종원;도재호;김나미;양재원;장규원
    • 한국식품영양과학회지
    • /
    • 제32권3호
    • /
    • pp.370-374
    • /
    • 2003
  • 홍삼 분쇄의 신 가공 기술로서 비충격 분쇄방식인 cell cracker의 공장 적용 가능성을 제시하고 홍삼분말의 품질고급화에 기초자료로 활용하고자, 기존의 hammer mill(충격분쇄방식)과 cell cracker에 의한 분쇄방식으로 홍삼분말을 제조한 후 물성, 표면구조적 특성 및 관능적 특성을 측정하였다. 입도분석에서 sieve shaker로 분석한 결과, 100 mesh 이상은 모두 95%수준으로 비슷한 분포를 나타냈고 120 mesh 이상은 hammer mill로 분쇄한 홍삼분말이 높았으며 그 밖의 각 mesh별 입도분포는 큰 차이를 나타내지 않았다. Laser scattering analyzer로 분석한 결과 hammer mill로 분쇄한 홍분말의 입도분포는 최소 0.77$\mu\textrm{m}$에서 최대 128.07$\mu\textrm{m}$으로, cell cracker로 분쇄한 홍삼분말 4.24~180.07$\mu\textrm{m}$보다 분포가 넓었으며, 평균 입자 크기는 cell cracker로 분쇄한 홍삼분말이 크고 표준편차는 hammer mill로 분쇄한 홍삼분말이 크게 나타났다. 비표면적은 hammer mill로 분쇄한 홍삼분말이 1.42 $m^2$/g로 cell cracker로 분쇄한 홍삼분말 0.59 $m^2$/g보다 높게 나타났고, 표면구조적 특성은 hammer mill로 분쇄한 홍삼분말은 크고 작은 입자가 불균일하게 분포하고 있으며, 개별입자의 형태는 부등형의 거칠게 연마된 돌 모양에 가깝고 표면은 작고 부드러운 솜털모양을 하고 있는 반면에, cell cracker로 분쇄한 홍삼분말은 입자크기가 상대적으로 고르게 분포하고 있으며 개별입자의 형태는 부등형의 조각난돌 모양의 형태로 관찰되었다.

불균일 입도를 가지는 기류식 고체 처리 시스템을 위한 해석모델 (Analysis model for the pneumatic solid processing system in non-uniform particle size condition)

  • 최동환;최상민
    • 한국연소학회:학술대회논문집
    • /
    • 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
    • /
    • pp.229-231
    • /
    • 2015
  • In pneumatic reactor, hydrodynamic relation between gas and solid is important and particle size has a significant effect on this relation. In this reason, we analyzed drying and calcine process with a corrected model by considering the effect of the particle size distribution(PSD) with different seven particle groups by particle size.

  • PDF

일부 분진 작업장에서의 폭로분진의 입경분포와 호흡성 분진 비율 (Size Distributions and Respirable Mass Fraction of Exposed Dust in Work Environment)

  • 김영식
    • 한국환경과학회지
    • /
    • 제1권2호
    • /
    • pp.25-31
    • /
    • 1992
  • Authors Investigated the particulate size distribution in work environment of Banwol and Changwon industry complex. Size distributions of particles exposured to workers in welding and in grounding process were evaluated by personal cascade impactors. Personal air samplers with personal cascade impactor were attached to the workers. The mass median diameter measured in welding sites were 0.3 to 3.BUm and in grinding sites were 1.5 to 2.6htn. Respirable matter fractions were ranged 32.67 to 65.055. Respirable matter fractions were calculated from the sixte distribution data by the respirable particle mass of the ACGIH criteria. The study relating to characteristics of particle of other industries and particulate sixte distribution is more needed in the near future

  • PDF

서울 대기 Aerosol의 물리적 특성 : 가시광선의 산란 (Physical Characteristics of Atmospheric Aerosols in Seoul : Scattering of Visible Light)

  • 김필수
    • 한국대기환경학회지
    • /
    • 제4권2호
    • /
    • pp.28-37
    • /
    • 1988
  • Light scattering coefficient of visible light by atmospheric aerosol over the size range 0.01-10$\mu$m is determined from scattering efficiency and aerosol size distribution. Aerosol number distribution as a function of particle diameter dN/dlog D decreases rapidly as increasing particle size. Distribution of scattering coefficient d$\sigma_s/dlog$ D is mostly accumulated in diameter 0.1-2.0 $\mu$m showing its maximum in the vicinity of 0.6$\mu$m. This means that the visible light in the atmosphere is mainly scattered by these particles. Diurnal variation of scattering coefficient $\sigma_s$ appears its maximum in the morning, while minimum in the afternoon which agrees with the aerosol number distribution in the size range 0.1-2.0 $\mu$m.

  • PDF

A Comparison of Size and Power of Tests of Hypotheses on Parameters Based on Two Generalized Lindley Distributions

  • Okwuokenye, Macaulay;Peace, Karl E.
    • Communications for Statistical Applications and Methods
    • /
    • 제22권3호
    • /
    • pp.233-239
    • /
    • 2015
  • This study compares two generalized Lindley distributions and assesses consistency between theoretical and analytical results. Data (complete and censored) assumed to follow the Lindley distribution are generated and analyzed using two generalized Lindley distributions, and maximum likelihood estimates of parameters from the generalized distributions are obtained. Size and power of tests of hypotheses on the parameters are assessed drawing on asymptotic properties of the maximum likelihood estimates. Results suggest that whereas size of some of the tests of hypotheses based on the considered generalized distributions are essentially ${\alpha}$-level, some are possibly not; power of tests of hypotheses on the Lindley distribution parameter from the two distributions differs.

System Size and Service Size Distributions of a Batch Service Queue

  • Lee, Soon-Seok;Lee, Ho-Woo;Yoon, Seung-Hyun;Nadrajan, R.
    • 한국경영과학회지
    • /
    • 제18권3호
    • /
    • pp.179-186
    • /
    • 1993
  • We derive the arbitrary time point system size distribution of M/ $G^{B}$1 queue in which late arrivals are not allowed to join the on-going service. The distribution is given by P(z) = $P_{4}$(z) $S^{*}$ (.lambda.-.lambda.z) where $P_{4}$ (z) is the probability generating function of the queue size and $S^{*}$(.theta.) is the Laplace-Stieltjes transform of the service time distribution function. We also derive the distribution of the service siez at arbitrary point of time. time.

  • PDF