• Title/Summary/Keyword: Temperature Profile

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Experiment on Settling Behaviour of Fine Mineral Particles (광물성 미립자의 침전거동에 관한 실험)

  • Kim, Jong-Woo
    • Journal of the Korean Society of Hazard Mitigation
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    • v.5 no.1 s.16
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    • pp.13-21
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    • 2005
  • Experiments on settling behaviour of fine-grained particles without destroying the large fragile aggregates were carried out in still water with a CCD (Charged Coupled Device)-Camera. The experiments dealt with the measuring of the vertical concentration profile of cohesive particles with a CCD-Camera and the physico-chemical influences (NaCl, density, temperature and pH value) on the vertical distribution of the concentration. The vertical concentration profile of fine suspended particles (alumina and quartz) was possible up to $20,000\;mg/{\ell}$ with a CCD-Camera. The vertical concentration profile of cohesive sediments was on the decrease because of the increasing initial concentration, temperature and salinity. The vertical concentration profile of alumina was on the decrease quicker than quartz with increasing salinity. Furthermore, the pH value affects the settling behaviour of alumina. At a PH value of 4.2 the settling rate of the particles was very low and on the increase until pH 8.9 because of the aggregation behaviour of particles. From the PH value of 9 the average settling velocity was on the decrease.

Thermo-mechanical compression tests on steel-reinforced concrete-filled steel tubular stub columns with high performance materials

  • David Medall;Carmen Ibanez;Ana Espinos;Manuel L. Romero
    • Steel and Composite Structures
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    • v.49 no.5
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    • pp.533-546
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    • 2023
  • Cost-effective solutions provided by composite construction are gaining popularity which, in turn, promotes the appearance on the market of new types of composite sections that allow not only to take advantage of the synergy of steel and concrete working together at room temperature, but also to improve their behaviour at high temperatures. When combined with high performance materials, significant load-bearing capacities can be achieved even with reduced cross-sectional dimensions. Steel-reinforced concrete-filled steel tubular (SR-CFST) columns are one of these innovative composite sections, where an open steel profile is embedded into a CFST section. Besides the renowned benefits of these typologies at room temperature, the fire protection offered by the surrounding concrete to the inner steel profile, gives them an enhanced fire performance which delays its loss of mechanical capacity in a fire scenario. The experimental evidence on the fire behaviour of SR-CFST columns is still scarce, particularly when combined with high performance materials. However, it is being much needed for the development of specific design provisions that consider the use of the inner steel profile in CFST columns. In this work, a new experimental program on the thermo-mechanical behaviour of SR-CFST columns is presented to extend the available experimental database. Ten SR-CFST stub columns, with circular and square geometries, combining high strength steel and concrete were tested. It was seen that the circular specimens reached higher failure times than the square columns, with the failure time increasing both when high strength steel was used at the embedded steel profile and high strength concrete was used as infill. Finally, different proposals for the reduction coefficients of high performance materials were assessed in the prediction of the cross-sectional fire resistance of the SR-CFST columns.

Influence of relative distance between heater and quartz crucible on temperature profile of hot-zone in Czochralski silicon crystal growth (쵸크랄스키법 실리콘 성장로에서 핫존 온도분포 경향에 대한 히터와 석영도가니의 상대적 위치의 영향)

  • Kim, Kwanghun;Kwon, Sejin;Kim, Ilhwan;Park, Junseong;Shim, Taehun;Park, Jeagun
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.28 no.5
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    • pp.179-184
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    • 2018
  • To lessen oxygen concentrations in a wafer through modifying the length of graphite heaters, we investigated the influence of relative distance from heater to quartz crucible on temperature profile of hot-zone in Czochralski silicon-crystal growth by simulation. In particular, ATC temperature and power profiles as a function of different ingot body positions were investigated for five different heater designs; (a) typical side heater (SH), (b) short side heater-up (SSH-up), (c) short side heater-low (SSH-low), (d) bottom heater without side heater (Only-BH), and (e) side heater with bottom heater (SH + BH). It was confirmed that lower short side heater exhibited the highest ATC temperature, which was attributed to the longest distance from triple point to heater center. In addition, for the viewpoint of energy efficiency, it was observed that the typical side heater showed the lowest power because it heated more area of quartz crucible than that of others. This result provides the possibility to predict the feed-forward delta temperature profile as a function of various heater designs.

Numerical Simulation of Vertical Wall Fires I. Turbulent Natural Convection Along Vertical Wall (수직벽화재의 수치 시뮬레이션 I. 수직벽 난류자연대류)

  • Park, Woe-Chul;Trouve, Arnaud
    • Fire Science and Engineering
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    • v.22 no.3
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    • pp.181-187
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    • 2008
  • Numerical simulation of natural convection along a vertical wall was carried out to evaluate the computational fluid dynamics simulator, which is to be utilized for study of vertical wall fires. The computed velocity and temperature profiles were compared with measurements over the turbulent boundary layer formed along the wall of 4m high and constant temperature. It fumed out that the simulator with default parameters failed to predict the turbulent natural convection showing the boundary layer flow laminar. The grid size $\Delta$x=5mm, ${\Delta}y={\Delta}z=10mm$ and Smagorinsky constant of the large eddy simulation $C_s$=0.1 were chosen through parametric investigations. Though turbulent mixing was not enough, the velocity distribution near wall, peak velocity, and temperature profile in the turbulent boundary layer agreed well with the measurements.

A Study on Synthesis and Characterization of TiZrB$_2$ Composite by SHS Microwave (SHS 마이크로파에 의한 TiZrB$_2$ 복합재료의 합성 및 특성연구)

  • 이형복;윤영진;오유근;안주삼
    • Journal of the Korean Ceramic Society
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    • v.36 no.1
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    • pp.7-14
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    • 1999
  • TiZrB2 solid solution was synthesized using fine powders of Ti, Zr and B by SHS microwave process. The characterization of the synthesized powder and sintered bodies ws investigated. The combustion temperature and rate were increased with increasing the mole ratio of Zr in temperature profile, and showed the maximum combustion temperature and velocity values of 285$0^{\circ}C$ and 14.6mm/sec in Ti0.2Zr0.8B2 composition. Phase separation has been occured into a composite with TiB2 and ZrB2 phases from TiZrB2 solid solution, which was hot pressed sintering at 30 MPa for an hour at 190$0^{\circ}C$. At the composition of Ti0.8Zr0.2B2 the best properties has been obtained in relative density, bending strength, fracture toughness and hardness, with 99%, 680 MPa, 7.3MPa.m1/2 and 2750 Kg/$\textrm{mm}^2$ respectively.

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A study of the removal efficiency of acidic gas at various operating conditions using Computation Fluid Dynamics (전산유체역학을 이용한 반건식 반응기의 운전조건에 따른 산성가스제거효율에 관한연구)

  • Lee, Geon-Ju
    • Journal of the Korea Organic Resources Recycling Association
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    • v.19 no.1
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    • pp.93-101
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    • 2011
  • The modeling of SDR was carried out for the application of the solid waste incineration system. To find optimum operating condition for removal of acidic gases, computation fluid dynamic(CFD) model was used. In this study, the temperature profile of SDR(spray dry reactor) and the gas velocity profile for different models were investigated. In this model, the diameter of SDR was 3 meter and the height of SDR was 9 meter. The amount of inlet combustion gas of SDR was $6,125Nm^3/hr$ and the inlet temperature of SDR was 493 K. The amount of lime injection of SDR was 151 kg/hr. When the inlet shape of SDR was changed, the temperatur of SDR was changed and the gas velocity of SDR was 0.48 m/sec to 1.17m/sec and the outlet gas velocity of SDR was 6.9 m/sec to 7.42m/sec As a result of modeling, the average velocities in SDR and outlet were 0.489 m/sec and 7.424 m/sec, respectively, in which the temperature of outlet in SDR was 448 K.

Manufacturing of Meat Flavor Extract used for Browning Reaction (Browning Reaction을 이용한 Meat Flavor Extract의 개발)

  • Kim Duk-Sook;Kim Jong-Seung
    • The Korean Journal of Food And Nutrition
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    • v.17 no.3
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    • pp.313-321
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    • 2004
  • Separation-concentration of sulfur containing heterocyclic compounds(SCHC) from many reaction meat flavors manufactured with Maillard reaction was carried out. Profile of SCHC was identified and analyzed by GC and GC-MSD. The results were as follows. 1. Profile of SCHC could be identified 7 kinds thiazole and 11 kinds thiophene, the major produced compounds were thiophene, thiazolidine, 4-methyl-5-thiazole ethanol. 2. In the case of SCHC, relationship between changes of reaction conditions and the kind of produced components were as same, but produced amounts appeared the difference. Producing amount of complexed SCHC and caramellike note as well as oxygen containing heterocyclic compounds were high level more than high reaction temperature and long time reaction period. 3. Producing ratio of comparative simple structural SCHC were the highest level at reaction conditions of moisture content 50%, reaction temperature 100$^{\circ}C$ and reaction time 2 hours. Reaction conditions for the revelation of reaction meat flavor were below 110$^{\circ}C$ and less than 2 hours. 4. Relationship between moisture content and reaction temperature as well as reaction time had very relative relation. From the change of moisture content and reaction conditions could be obtained the simultaneously profile. Signal presentation for production of reaction meat flavor could be from extraction-separation-concentration of SCHC through simplification of raw-materials in the flavor and seasoning food industry.

Proteomic Changes in Odae Polished White Rice Grown at Different Cultivation Conditions (재배환경에 따라 변화하는 오대벼 백미의 단백질체 분석)

  • Lee, Ju-Young;Lee, Jin-Woo;Kim, Young-Ran;Yeom, Yu-Jin;Lim, Jin-Kyu
    • Journal of Applied Biological Chemistry
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    • v.55 no.2
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    • pp.79-83
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    • 2012
  • It has been known that the proteome profiles in the period of growth and development of rice are changed by the growth conditions including temperature, soil, and fertilization. In this study, the proteome profiles of Odae polished white rice grown in Chulwon and Chilgog were compared on 2-dimensional(D) gels. The differentially expressed proteins were selected from the 112 identified total proteins and classified into functional groups. The most significantly differentially expressed proteins were stress responsive proteins; Ent-kaur-16-ene synthase, which is responsible for synthesizing a plant hormone gibberellin, was expressed in Chulwon rice and heat shock proteins were in Chilgog rice, respectively. Xylanase inhibitor protein, which inhibits the enzyme xylanase produced by pathogenic fungi and Bacilli, was expressed significantly high in Chilgog rice grown at high temperature. Differential expressions of transporter proteins were observed both in Chulwon and Chilgog rice. Regarding the facts that Chilgog rice contained relatively higher amount of proteins than Chulwon rice and Chulwon rice showed large number of proteins were differentially expressed, it can be concluded that different cultivation conditions could change the protein expression profiles in rice in various ways, including elevation of protein amount or differential expressions of specific proteins, etc. The results suggest that the characteristics of the profiles of the proteome in the polished white rice are definitely changed by the environmental factors including high temperature. The results can be utilized for the development of the proper cultivation conditions for the production of high quality rice with good palatability.

Annealing Effect on Exchange Bias in NiFe/FeMn/CoFe Trilayer Thin Films

  • Kim, Ki-Yeon;Choi, Hyeok-Cheol;You, Chun-Yeol;Lee, Jeong-Soo
    • Journal of Magnetics
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    • v.13 no.3
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    • pp.97-101
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    • 2008
  • We investigated the exchange bias fields at the NiFe/FeMn and FeMn/CoFe interfaces in 18.9-nm NiFe/15.0-nm FeMn/17.6-nm CoFe trilayer thin films as the annealing temperature was varied from room temperature to $250^{\circ}C$ in a vacuum for 1 hour in a magnetic field of 150 Oe. Interestingly, magnetic hysteresis (M-H) measurements showed that NiFe/FeMn/CoFe trilayer thin films exhibited a completely contrasting variation of the exchange bias fields at both the NiFe/FeMn and FeMn/CoFe interfaces with annealing temperatures. High-angle X-ray diffraction (XRD) measurements indicated the absence of any discernible effect of thermal treatment on the NiFe(111) and FeMn(111) peaks. The compositional depth profile obtained from X-ray photoelectron spectroscopy (XPS) results presented the asymmetric compositional depth profiles of the Mn and Fe atoms throughout the FeMn layer. We contend that this asymmetric compositional depth profile and the preferential Mn diffusion into the NiFe layer, compared to that into the CoFe layer, are conclusive experimental evidence of the contrasting variation of the exchange bias fields at two interfaces having a common polycrystalline FeMn(111) layer.

Surface Hardness Improvement of Larch Wood Using Thermal-Compression (열압밀화를 이용한 낙엽송의 표면경도 개선)

  • Hwang, Sung-Wook;Park, Sang-Bum;Suh, Jin-Suk;Kim, Jong-In;Hong, Seong-Cheol;Lee, Won-Hee
    • Journal of the Korea Furniture Society
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    • v.23 no.4
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    • pp.460-466
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    • 2012
  • This study was conducted to investigate the surface hardness of thermally-compressed larch wood by compression set and temperature. The surface hardness of thermally-compressed larch wood increased with increasing compression set and temperature. For compression set 60%, the specific gravity was increased as 0.93. However, the surface hardness was lower value as 31.1 N/$mm^2$ compared with a similar specific gravity of the tropical timber. For density profile, less than compression set 40%, compression was observed mainly surface area. On the other hand, more than 50%, density profile variation was reduced by compression of central part. Results of this study indicate that thermally-compressed larch wood can be replace some imported hardwoods such as oak or cherry. However, thermally-compressed larch wood was difficult to replace the tropical timber being imported in terms of surface hardness.

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