• Title/Summary/Keyword: sequential properties

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Light Weight Design of the Commercial Truck Armature Core using the Sequential Response Surface Method (순차적 반응표면법을 이용한 상용 트럭 아마추어 코어 경량화 설계)

  • H. T. Lee;H. G. Kim;S. J. Park;Y. G. Jung;S. M. Hong
    • Transactions of Materials Processing
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    • v.32 no.1
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    • pp.12-19
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    • 2023
  • The armature core is a part responsible for the skeleton of the steering wheel. Currently, in the case of commercial trucks, the main parts of the parts are manufactured separately and then the product is produced through welding. In the case of this production method, quality and cost problems of the welded parts occur, and an integrated armature core made of magnesium alloy is used in passenger vehicles. However, in the case of commercial trucks, there is no application case and research is insufficient. Therefore, this study aims to develop an all-in-one armature core that simultaneously applies a magnesium alloy material and a die casting method to reduce the weight and improve the quality of the existing steel armature core. The product was modeled based on the shape of a commercial product, and finite element analysis (FEA) was performed through Ls-dyna, a general-purpose analysis program. Through digital image correlation (DIC) and uniaxial tensile test, the accurate physical properties of the material were obtained and applied to the analysis. A total of four types of compression were applied by changing the angle and ground contact area of the product according to the actual reliability test conditions. analysis was carried out. As a result of FEA, it was confirmed that damage occurred in the spoke area, and spoke thickness (tspoke), base thickness (tbase), and rim and spoke connection (R) were designated as design variables, and the total weight and maximum equivalent stress occurring in the armature core We specify an objective function that simultaneously minimizes . A prediction function was derived using the sequential response surface method to identify design variables that minimized the objective function, and it was confirmed that it was improved by 22%.

Characterization of Mineralogical and Physicochemical Properties of Soils Contaminated with Metals at Gahak Mine (가학광산 주변 중금속 함유 토양입자의 이화학적·광물학적 특성연구)

  • Lee, Choong Hyun;Lee, Seon Yong;Park, Chan Oh;Kim, Jong Won;Lee, Sang Hwan;Park, Mi Jeong;Jung, Moon Young;Lee, Young Jae
    • Journal of Soil and Groundwater Environment
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    • v.20 no.4
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    • pp.83-89
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    • 2015
  • Soil samples collected in an area of Gahak Mine were investigated for the characterization of mineralogical and physicochemical properties of contaminants in soils. It is found that soils in the study area are contaminated by lead (Pb), copper (Cu), zinc (Zn), cadmium (Cd), in which their concentrations are 595.3 mg/kg, 184.9 mg/kg, 712.8 mg/kg, and 10.64 mg/kg, respectively. All the concentrations exceed the concern criteria of Korean standard. Upon distribution patterns of metals identified by the sequential extraction procedure, our results show that more than 50% of metals are found as a residual type, and 30% are accounted for the association of Fe/Mn oxides. Interestingly, XRD results show that minium (Pb3O4) and cuprite (Cu2O) are identified in the soil samples, suggesting that the sources of the contaminants for Pb and Cu are these minerals. In SEM images, tens of µm of Pb oxides and Pb silicate-minerals are observed. We, therefore, note that the contamination of metals in the study area results from the direct influx and disturbance of tailings. Our findings indicate that the characterization of physicochemical and mineralogical properties of contaminated soils is a critical factor and plays an important role in optimizing recovery treatments of soils contaminated in mine development areas.

A Study on Optical Properties of Nanocomposite Composed of Au Nanorods and Organic Dyes (금 나노막대와 유기 염료로 구성된 나노복합체의 광학특성 연구)

  • Kim, Ki-Se;Yoo, Seong Il;Sohn, Byeong-Hyeok
    • Clean Technology
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    • v.20 no.2
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    • pp.141-145
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    • 2014
  • In this study, we studied optical properties on the layer-by-layer (LbL) assemblies consisting of Au nanorods and organic dyes. For this purpose, poly (allylamine hydrochloride), PAH and poly (styrene sulfonate), PSS were selected as ionic polymers and rhodamine B isothiocyanate (RB) was utilized as an organic dye based on its spectral overlap with plasmon band of Au nanorods. In the view point of assembling methods, RB was covalently attached to PAH, then, LbL structure of Au [PSS/PAH]2/PSS/PAH-RB was prepared by sequential coating of PAH, PSS, PAH-RB on Au nanorods. Since the prepared LbL assembly exhibits both plasmonic and fluorescent properties, we studied the mutual nanorod-dye properties by dissolving Au nanorods.

On a Performance Comparison of Pitch Search Algorithms by using a Correlation Properties for the CELP Vocoder (CELP 보코더의 피치 검색시간 단축법의 비교)

  • 배명진
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1993.06a
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    • pp.280-287
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    • 1993
  • Code Excited Linear Prediction(CELP) speech coders exhibit good performance at data rates as low as 4800bps. The major drawback to CELP type paper, a comparative performance study of three pitch searching algorithms for the CELP vocoder was conducted. For each of the algorithms, a standard pitch searching algorithm was used by the sequential pitch searching algorithm that was implimented in the QCELP vocoder. The algorithms used in this study were 1) using the skip table(TABLE), 2) using the symmetrical property of the autocorrelation(SYMMT), and 3) using the preprocessing autocorrelation(PREPC). Performance scores are presented for each of the three pitch searching algorithms based on computation speed and on pitch prediction error.

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Optimization of Medium Composition for Growth of Leuconostoc mesenteroides

  • Kim, Hyeon;Eom, Hyeon-Ju;Seo, Dong-Mi;Han, Nam-Su
    • 한국생물공학회:학술대회논문집
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    • 2003.04a
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    • pp.153-156
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    • 2003
  • The MRS medium is widely used as an optimized medium for the growth of Lactobacillus spp. and also used for the growth of Leuconostoc spp. Leuconostoc mesenteroides shows quite different physicochemical properties compared to Lactobacilli spp. and it is one of the major strain of kimchi fermenting microorganisms with its usefulness in our traditional foods and availability in biotechnology in the future, specifically tailor-made medium is necessary for the growth of Leuconostoc mesenteroides. Sequential experimental designs (Plackett-Burman, fractional factorial, steepest ascent, central composite design and response surface methodology) were introduced to optimize and improve the Leuconostoc medium. Fifteen medium ingredients were investigated and fructose, sodium acetate and ammonium citrate were determined to give a critical and positive effect for cell-growth. The yield of biomass using the optimal medium was improved more than that of the MRS medium and the result of fed-batch culture showed the capability of the improvement in cell mass similar to the E.coli system.

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An Investigation on the Effect of Stabilization Methods and Leaching characteristics of Heavy Metals in Paddy Soils contaminated by Heavy Metal under Submerged Condition (담수조건에 따른 토양 내 중금속 용출특성과 안정화공법의 효과 검토)

  • Yu, Chan;Yun, Sung-Wook;Kang, Sin-Il;Jin, Hae-Geun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09a
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    • pp.1201-1212
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    • 2010
  • In order to investigate on the effect of stabilization methods for rice paddies contaminated by heavy metals, a series of lab-scale model test was carried out by applying the characteristics of submerged Paddy soil. To perform the lab-scale model test, columns were made by acrylic with the dimension of diameter=10cm, thickness=0.5cm and were filled with soils which was contaminated were mixed with stabilization agents(lime stone 5% and steel refining slag 5% respectively). To manipulate the reduction condition, soils in the columns were submerged with distilled water. And then soil water and subsurface water in each column were sampled in the regular term and analysed the various physical and chemical properties.

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Design of a Curtailed-SPRT Control Chart (단축-축차관리도의 설계)

  • Chang, Young-Soon
    • Journal of the Korean Operations Research and Management Science Society
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    • v.34 no.1
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    • pp.29-37
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    • 2009
  • This paper proposes a curtailed-sequential probability ratio test (SPRT) control chart. For using the conventional SPRT control chart, the number of items inspected in a sampling point should have no restriction since items in a sampling point are inspected one by one until an SPRT Is terminated. The number of observations taken in a sampling point, however, has an upper bound since sampling and testing of an item is time-consuming or expensive. When the sample size reaches the upper bound without evidence of an in-control or out-of-control state of a process, the proposed chart makes a decision using the sample mean of all observations taken in a sampling point. The properties of the Proposed chart are obtained by a Markov chain approach and the performance of the chart is compared with fixed sample size (FSS) and variable sample size (VSS) control charts. A comparative study shows that the proposed chart performs better than VSS control charts as well as conventional FSS control charts.

LTPS (Low Temperature Poly Si) Technology Based on SLS (Sequential Lateral Solidification) Crystallization for Advanced Mobile Display

  • Kang, Myung-Koo;Kim, Hyun-Jae;Kim, Chi-Woo;Kim, Hyung-Guel
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.1756-1760
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    • 2006
  • LTPS technology based on SLS Crystallization was intensively reviewed. LTPS structure produced by SLS crystallization is composed of much larger grains compared with conventional ELA crystallization structure, which can give higher TFT performances. However, TFT performance uniformity and anisotropy problem should be solved for it to be used in mass production. TFT performance uniformity was from main grain boundary position and could be solved by equal defect area structure $(EDAS^{TM})$. TFT performance anisotropy could be also solved by multi-channel (MC) structure that can make parallel component in perpendicular channel direction. The higher TFT performances from SLS technology can make superior optical and/or electrical properties and has been adopted in mass production successfully.

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Properties of Sequential Lateral Solidification (SLS) Crystallized Poly-Si Films and Melting Process Simulation

  • Kim, Yong-Hae;Sohn, Choong-Yong;Chung, Choong-Heui;Ko, Young-Wook;Lee, Jin-Ho
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.248-251
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    • 2003
  • The large size grain of poly-Si film is obtained above the upper limit of excimer laser energy at which the random nucleation occurs. We simulate the time dependent temperature profile of ${\alpha}-Si/SiO_2/Si$ substrate structure according to the excimer laser energy with $ANSYS^{\circledR}$ simulator. As the thickness is increased, the laser energy for the melting of ${\alpha}-Si$ film is increased.

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RSA vs DEM in view of particle packing-related properties of cementitious materials

  • Li, Kai;Stroeven, Piet
    • Computers and Concrete
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    • v.22 no.1
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    • pp.83-91
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    • 2018
  • Various systems for simulating particulate matter are developed and used in concrete technology for producing virtual cementitious materials on the different levels of the microstructure. Basically, the systems can be classified as two distinct families, namely random sequential addition systems (RSAs) and discrete element methods (DEMs). The first type is hardly being used for this purpose outside concrete technology, but became popular among concrete technologists. Hence, it is of utmost relevance to compare the two families in their capabilities, so that the reliability of produced data can be estimated. This paper pursues to do this on the basis of earlier published material of work performed by a succession of PhD students in the group of the second author. Limited references will be given to external sources.