• Title, Summary, Keyword: Size-distribution

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Characteristic of size distribution of rock chip produced by rock cutting with a pick cutter

  • Jeong, Hoyoung;Jeon, Seokwon
    • Geomechanics and Engineering
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    • v.15 no.3
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    • pp.811-822
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    • 2018
  • Chip size distribution can be used to evaluate the cutting efficiency and to characterize the cutting behavior of rock during cutting and fragmentation process. In this study, a series of linear cutting tests was performed to investigate the effect of cutting conditions (specifically cut spacing and penetration depth) on the production and size distribution of rock chips. Linyi sandstone from China was used in the linear cutting tests. After each run of linear cutting machine test, the rock chips were collected and their size distribution was analyzed using a sieving test and image processing. Image processing can rapidly and cost-effectively provide useful information of size distribution. Rosin-Rammer distribution pamameters, the coarseness index and the coefficients of uniformity and curvature were determined by image processing for different cutting conditions. The size of the rock chips was greatest at the optimum cut spacing, and the size distribution parameters were highly correlated with cutter forces and specific energy.

Mapping Particle Size Distributions into Predictions of Properties for Powder Metal Compacts

  • German, Randall M.
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • pp.704-705
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    • 2006
  • Discrete element analysis is used to map various log-normal particle size distributions into measures of the in-sphere pore size distribution. Combinations evaluated range from monosized spheres to include bimodal mixtures and various log-normal distributions. The latter proves most useful in providing a mapping of one distribution into the other (knowing the particle size distribution we want to predict the pore size distribution). Such metrics show predictions where the presence of large pores is anticipated that need to be avoided to ensure high sintered properties.

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The Transportation Size and the Location of Distribution Centers in a Distribution System (물류시스템에서 수송크기와 물류센터의 위치)

  • Chang, Suk-Hwa
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.30 no.3
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    • pp.12-19
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    • 2007
  • This paper is to determine the transportation size and the location of distribution centers to minimize logistics cost in a distribution system where products are transported from the distribution centers to the retailers. Logistics cost consists of the fixed cost of distribution centers, the transportation cost from the distribution centers to the retailers and the inventory holding cost in the retailers. The logistics cost is affected by the transportation size and the location of distribution centers. The transportation size affects transportation cost and inventory holding cost. The location of distribution centers affects the transportation cost. A mathematical model is formulated and the algorithm is developed. A numerical example is shown to explain the problem.

Influence of feeding mode on cooling crystallization of L-lysine in Couette-Taylor crystallizer

  • Nguyen, Anh-Tuan;Kim, Woo-Sik
    • The Korean Journal of Chemical Engineering
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    • v.34 no.7
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    • pp.2002-2010
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    • 2017
  • A continuous Couette-Taylor (CT) crystallizer was used to apply a multiple feeding mode strategy to enhance the crystal size and size distribution of L-lysine crystals in cooling crystallization. With a 5-min mean residence time, feed concentration of 900 g/l, and rotation speed of 700 rpm, the multiple feeding mode strategy Run-III (D21) produced a large crystal size of $139{\mu}m$ and coefficient of variation (CV) for the size distribution of 0.39, both of which were significantly enhanced when compared with the conventional feeding mode Run-I (D1) that produced a crystal size of $82{\mu}m$ and CV for the size distribution of 0.53. Essentially, the crystal size was enhanced around 70%, while the size distribution was improved around 28%. Finally, the impact of the multiple feeding mode strategy on the crystal size and size distribution is explained in terms of effective control of the supersaturation.

A Study on the Determination of Optimal Lot Size in Distribution System (물류시스템에서의 최적 로트크기 결정원칙에 관한 연구)

  • 김상직;김영식;김영겸
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.18 no.35
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    • pp.39-46
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    • 1995
  • This study is to find the optimal lot size method in the distribution system. In general, the lot size methods used in the distribution system is the same as the methods of the MRP system. The lot size methods used in this study are LFL, EoQ, LTC and POQ.. Resulting in case study, LTC is the optimal lot size method in the distribution system. In distribution system, VRP and VSP shall be investgated.

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Particle Size and Shape Analysis : The Key to Success in Metal Powder Production

  • Pankewitz, Axel;Park, Yong-Jae
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • pp.702-703
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    • 2006
  • The particle size distribution and shape are among the important parameters for characterisation of quality of metal powders. Specific material properties such as ability to flow, reactivity as well as compressibility and its hardening potentials hence the most important characteristics of sintered metals - are determined by the size distribution and shape. The correct particle size distribution and particle shape information are the key to best product quality in atomisation processes of aluminium, milling of pure metals and other processes. This paper presents state-of-the-art technology for characterization of particle size distribution and shape.

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Study on the Contribution of Mixing Effects in Sampling Tube and Condensation Nuclei Counter(CNC) to the measurement of size distribution obtained using Differential Mobility Analyzer and CNC (Differential Mobility Analyzer(DMA)와 Condensation Nuclei Counter(CNC)를 이용한 입자크기 분포 측정에서 샘플링 튜브와 CNC에서의 혼합 효과가 입자 크기 분포 측정에 미치는 영향에 관한 연구)

  • Lee, Youn-Soo;Ahn, Kang-Ho
    • Proceedings of the KSME Conference
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    • pp.104-109
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    • 2001
  • The time to measure the size distribution using Condensation Nuclei Counter(CNC) and Differential Mobility Analyzer(DMA) can be shortened by classifying particles ramping the DMA voltage exponentially and continuously. In measurement, particles sampled at different time are mixed together going through sampling tube and CNC. Because the size distribution is inversed by using detector responses to sampling time intervals in this accelerated method, the mixing effects give inversion errors to the size distribution. The mixing effects can be considered by appling the transfer function with mixing effects to the data inversion. The inversion considering this effects gives birth to the size distribution shifted to the opposite direction of the size scanning.

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Investigation on the Factors Determining the Size Distribution of Gold Nanoparticles in the Citrate Reduction Method

  • Kang, Ae-Yeon;Park, Dae-Keun;Lee, Cho-Yeon;Yun, Wan-Soo
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.554-554
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    • 2012
  • Controlling the size distribution of gold nanoparticles (NPs) is of great importance due to the fact that their properties are strongly dependent upon the size distribution as well as the size itself. In the citrate reduction method for gold NP synthesis, the citrate works as (1) a reducing agent, (2) a surfactant, and also (3) a weak base: it raises the pH of the whole reaction mixture. Here, we have extensively studied the all three roles of the citrate, by adding other reagents separately (NaBH4, CTAB, and NaOH) for the independent control of the three roles of the citrate. Among the roles of the citrate, that as a weak base was found to be the most critical parameter affecting the size distribution of gold NPs and the size distribution became much more improved with the increase of the solution pH, while adding a supplementary surfactant or reducing agent resulted in the formation of less homogeneous NPs.

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Analysis on the Relations of Droplet Size Distribution and Optical Depth in Water Curtain (워터커튼에서 액적의 크기 분포와 광학 두께의 상관관계 분석)

  • You, Woo Jun;Ryou, Hong-Sun
    • Fire Science and Engineering
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    • v.30 no.2
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    • pp.62-67
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    • 2016
  • In this study, the optical depth is analyzed with the effects of droplet size distribution of the water curtain nozzle to attenuate the radiative heat transfer. The HELOS/VARIO equipment is used for the measurement of the droplet size distributions. The spray characteristics are quantified by the investigation of Deirmenjian's modified gamma distribution function. The distribution constant of the nozzle can be obtained as ${\alpha}=1$ and ${\gamma}=5.2$. The generalized equation of the optical depth related with the droplet size distribution is introduced. These results will be applicable to the analysis of the design condition of the water curtain nozzle.

pH Dependent Size and Size Distribution of Gold Nanoparticles

  • Kang, Aeyeon;Park, Dae Keun;Hyun, Sang Hwa;Yun, Wan Soo
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.267.2-267.2
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    • 2013
  • In the citrate reduction method of gold nanoparticle (AuNP) synthesis, pH of the reaction mixture can have a considerable impact on the size and size distribution of AuNPs. In this work, effects of pH variation upon the size and its distribution were examined systematically. As the initial pH was change from 5.5 to 10.5, it showed an optimal pH around 7.5. At this pH, both of the size and the size distribution showed their minimum values, which was verified by transmission electron microscopy and UV-vis spectroscopy. This occurrence of optimal pH was discussed with the results of in situ monitoring pH during the reaction of AuNP synthesis.

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