• Journal of Environmental Science International
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• v.7 no.1
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• pp.36-40
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• 1998

This study was carried out to investigate the collection Efficiency of mass in collector step at the different of physical gas characterization. This work has focused on the dependence of the collection efficiency of mass in the collector zone of a two-stage set up field with gas temperature T and the dew point tmeperature. To identify the dependence of the mass collection efficiency on the Bounded plate of the collector zone MP.k by the spectre electric resistance of dust $p_e$. and the relative humidify ${\varphi}$, 20 at- tempts have been made with three different gas temperature ($50{\circ}C, 80{\circ}C, 110{\circ}C$) at different dew point. At the specific electric resistance of dust $p_e$=$10^6{\Omega}m$ which relative humidity corresponds to $\phi$ > 15%, a easy rise of the sounded plate secluded dust mass share was measured atwain. As the result of the higher cohesion imprisonment power due to the adsorbtion of particle, the rinse of the relative humidity developed on the particle surface. Therefore, the collection efficiency of mass was not predominant the high temperature T in the collector zone, neither was the pecific ellectric resistance of dust dependent.

• Earthquakes and Structures
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• v.16 no.2
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• pp.149-163
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• 2019

By integrating an active tuned mass damper (ATMD) and an inerter, the ATMDI has been proposed to attenuate undesirable oscillations of structures under the ground acceleration. Employing the mode generalized system, the dynamic magnification factors (DMF) of the structure-ATMDI system are formulated. The criterion can then be defined as the minimization of maximum values of the DMF of the controlled structure for optimum searching. By resorting to the defined criterion and the particle swarm optimization (PSO), the effects of varying the crucial parameters on the performance of ATMDI have been scrutinized in order to probe into its superiority. Furthermore, the results of both ATMD and tuned mass dampers inerter (TMDI) are included into consideration for comparing. Results corroborate that the ATMDI outperforms both ATMD and TMDI in terms of the effectiveness and robustness. Especially, the ATMDI may greatly reduce the demand on both the mass ratio and inerter mass ratio, thus being capable of further miniaturizing both the ATMD and TMDI. Likewise the miniaturized ATMDI still keeps nearly the same stroke as the TMDI with a larger mass ratio. Hence, the ATMDI is deemed to be a high performance control device with the miniaturization and suitable for super-tall buildings.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.49-50
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• 2003

To know the properties of single aerosol particle is an essential prerequisite for understanding its chemical reactions in the atmosphere. Single particle analysis has the advantage of providing a great amount of information that cannot otherwise be obtained using methods of bulk analysis. And single particle analysis needs the short sampling time and the small sampling mass for analysis. This allows for a better determination of the temporal variation of the component concentrations in aerosol particles. (omitted)

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.5
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• pp.97-103
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• 1998

The flow structure of particles for two different injectors has been investigated experimentally by means of a Phase Doppler Particle Analyzer(PDPA). Two injectors used in the present study are the pipe and contraction nozzle. Particles of 0.8${\mu}{\textrm}{m}$, 30${\mu}{\textrm}{m}$, 60 ${\mu}{\textrm}{m}$, and 100${\mu}{\textrm}{m}$ diameter were injected with a constant mass loading ratio of 0.01 and a Reynolds number of 13200. The initial mean velocity and turbulent intensity of particle are strongly influenced by the particle size and the injector geometry. The flow angles of particle at nozzle exit are sensitive to the particle size rather than the injector geometry.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.11
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• pp.876-885
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• 2009

Char oxidation experiments were performed with a sub-bituminous roto-middle coal in the Drop Tube Furnace (DTF) at atmospheric pressure condition. While temperatures varied between 900, 1100, 1400 $^{\circ}C$, particle size, mass, particle temperature, and CO/$CO_2$ concentration were obtained to be used for kinetic analysis of the char oxidation. This study addresses several different methods to analyze the char consumption rate, which are classified as energy balance method, ash-traced mass method, flue-gas based method, and particle size based method. The char consumption rate obtained with such methods was compared with the results of Monson et al.$^{(24)}$ While there are some differences between them because of differences in experimental apparatus and parameters to be measured, the kinetic results seems to be reasonable enough to be incorporated in a numerical modeling of coal combustion.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.1
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• pp.13-18
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• 1992

Three cattle, a sheep and a goat were slaughtered to determine the distribution of digesta particles and mean size of digesta particles. Aliquot samples of digesta in the diverse sites of the digestive tracts were fractionated by a wet sieving technique. Fractionated particles were analyzed by the magnetic grid analyzer system constructed by authors. Results showed that the proportion of particles in digesta was similar among the omasum, abomasums cecum, colon and rectum, but that for the reticulo-ruminal digesta was different from the others. The pattern of the mass base frequency distribution of particles was also similar in the post-ruminal digesta. Average Heywood's diameter (the diameter equivalent to that of a circle with equal area to a projected area of a given particle) was about 1.2 mm in the reticulo-ruminal digesta and decreased to 0.65 mm for cattle or to about 0.35 mm for sheep and goat in the omasal digesta. Average Heywood's diameter was about the same in the post-ruminal digesta. It is concluded that mean particle size and particle distribution in digesta of the rectum or feces reflect those in digesta of the omasum.

• Journal of Korean Society for Atmospheric Environment
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• v.6 no.1
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• pp.11-21
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• 1990

To quantitatively estimate the effect of yellow sand(loess) fromt he Northern China, various soil sources having similar chemical compositions to yellow sands should be separated and identified. After that, mass contribution for yellow sand can be calculated. The study showed that it was impossible to solve this problem by the traditional bulk analyses. However, particle-by-particle analysis by a CCSEM (computer controlled scanning electron microscope) gave enormous potentials to solve it. To perform this study, seven soil source data analyzed by CCSEM were obtained from Texas, U.S.A. Initially, each soil date was classified into two groups, coarse and fine particle groups since the particle number distribution showed a minimum occurring at 5.2$\mu$m of aerodynamic diameter. Particles in each group were then classified into one of the 283 homogeneous particle classes by the universal classification rule which had been built by an expert system in the early study. Further, mass fractions and their uncertainties for each class in each source were calculated by the Jackknife method, and then source profile matrix for the 7 soil sources was created. To use the profile matrix in the study of source contribution, it is necessary to test the degree of collinearity among sources. The profiles were tested by the singular value decomposition method. As a result, each soil source characterized by artificially created variables was totally independent each other and is ready to use in source contribution studies as a receptor model.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.157-163
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• 2011

Combustion of magnesium dust particle were fabricated test devices and combustion experiments were carried out. The ignition delay time were measured in change of magnesium particle mass flow rate in premixed flame. According to increasing magnesium particle mass flow rate, ignition delay time were more shorter. In addition, magnesium dust combustion temperature were measured different particle sizes and o/f ratio by two wavelength pyrometry. Dust combustion flame temperature is almost similarly, through to equivalence ratio, confirm the combustion flame temperature range characteristics.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.12
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• pp.660-667
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• 2013

This study presents a numerical investigation of the heat and mass transfer kinetics of a fin-tube-type adsorption bed using a two-dimensional numerical model with silica-gel and water as the adsorbent and refrigerant pair. The performance is strongly affected by the heat and mass transfer in the adsorption bed, but the details of the mass transfer kinetics remain unclear. The validity of inter-particle models used to simulate mass-transfer kinetics were examined, such as a constant pressure model and non-constant pressure model, and the valid ranges of the diffusion ratio for each model are proposed. The COP and SCP have been numerically calculated as the performance indexes according to the diffusion ratio. The constant pressure model, which is commonly used in previous research, was found to be valid only in a limited range of diffusion ratio.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.321-325
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• 2015

Determining the absolute neutrino mass scale and the neutrino mass hierarchy are central goals in particle physics, with important implications for the Standard Model. However, the final answer may come from cosmology, as laboratory experiments provide measurements for two of the squared mass differences and a stringent lower bound on the total neutrino mass - but the upper bound is still poorly constrained, even when considering forecasted results from future probes. Cosmological tracers are very sensitive to neutrino properties and their total mass, because massive neutrinos produce a specific redshift-and scale-dependent signature in the power spectrum of the matter and galaxy distributions. Stringent upper limits on ${\sum}m_v$ will be essential for understanding the neutrino sector, and will nicely complement particle physics results. To this end, we describe here a series of cosmological hydrodynamical simulations which include massive neutrinos, specifically designed to meet the requirements of the Baryon Acoustic Spectroscopic Survey (BOSS) and focused on the Lyman-${\alpha}$ ($Ly{\alpha}$) forest - also a useful theoretical ground for upcoming surveys such as SDSS-IV/eBOSS and DESI. We then briefly highlight the remarkable constraining power of the $Ly{\alpha}$ forest in terms of the total neutrino mass, when combined with other state-of-the-art cosmological probes, leaving to a stringent upper bound on ${\sum}m_v$.