• Title/Summary/Keyword: phase diagram

Search Result 528, Processing Time 0.029 seconds

Evaluation of Hot Tear Susceptibility of Al-Si-Mg-Cu Alloy System (Al-Si-Mg-Cu 합금계의 열간 균열 특성 평가방법에 관한 연구)

  • Son, Kwang-Suk;Park, Tae-Eun;Kim, Jin-Su;Kang, Sung-Min;Kim, Donggyu
    • Korean Journal of Metals and Materials
    • /
    • v.48 no.5
    • /
    • pp.436-444
    • /
    • 2010
  • The hot tear susceptibility of Al alloys was investigated by using a constrained-rod mold designed to quantify 8 types of tear tendency. The severity of the crack was scored by 5 grades on a scale of 0 to 4, with 0 being "no crack formed" and 4 being "complete separation by crack". The Hot Tear Susceptibility index (HTS) which consists of crack type scores and position scores, was proposed to compare the hot tear tendency of Al alloys. A356.0 cast alloy and AA6061 wrought Al alloy showed an HTS value of 27.5 and 53 respectively. The effects of Si, Cu, and Mg content on hot tear tendency were also investigated with a constrained-rod mold. The variation of HTS values with alloying elements represents similar behavior in the variation of the solidification range in a pseudo binary phase diagram.

Extraction of Pure Si from an Al-Si Alloy Melt during Solidification by Centrifugal Force (Al-Si 합금 융체로부터 순 실리콘의 원심분리 추출)

  • Cho, Ju-Young;Kang, Bok-Hyun;Kim, Ki-Young
    • Korean Journal of Metals and Materials
    • /
    • v.49 no.11
    • /
    • pp.874-881
    • /
    • 2011
  • The present study describes a new technique to extract the primary silicon from an Al-Si alloy melt using centrifugal force during its solidification. The primary silicon was separated from an Al-50 wt.%Si alloy by centrifugal force in the form of a foam, which facilitated subsequent acid leaching to extract the pure silicon due to its wide surface area. The foam recovery after centrifugal separation was decreased as centrifugal acceleration was increased. The final recovery after acid leaching became closer to the solid fraction of the alloy, which was calculated from the Al-Si binary phase diagram, with increasing centrifugal acceleration due to the effective removal of the attached Al on the foam. The purity of the primary silicon obtained by the centrifugal separation method was over 99.99%, with only aluminum being also present.

Beyond SDLC: Process Modeling and Documentation Using Thinging Machines

  • Al-Fedaghi, Sabah
    • International Journal of Computer Science & Network Security
    • /
    • v.21 no.7
    • /
    • pp.191-204
    • /
    • 2021
  • The software development life cycle (SDLC) is a procedure used to develop a software system that meets both the customer's needs and real-world requirements. The first phase of the SDLC involves creating a conceptual model that represents the involved domain in reality. In requirements engineering, building such a model is considered a bridge to the design and construction phases. However, this type of model can also serve as a basic model for identifying business processes and how these processes are interconnected to achieve the final result. This paper focuses on process modeling in organizations, per se, beyond its application in the SDLC when an organization needs further documentation to meet its growth needs and address regular changes over time. The resultant process documentation is created alongside the daily operations of the business process. The model provides visualization and documentation of processes to assist in defining work patterns, avoiding redundancy, or even designing new processes. In this paper, a proposed diagrammatic representation models each process using one diagram comprising five actions and two types of relations to build three levels of depiction. These levels consist of a static description, events, and the behavior of the modeled process. The viability of a thinging machine is demonstrated by re-modeling some examples from the literature.

Effect of Electrolysis Parameters on the Fractal Structure of Electrodeposited Copper

  • Na Wu;Chunxia Zhang;Shanyu Han;Juan An;Wentang Xia
    • Journal of Electrochemical Science and Technology
    • /
    • v.14 no.2
    • /
    • pp.194-204
    • /
    • 2023
  • Models based on diffusion-limited aggregation (DLA) have been extensively used to explore the mechanisms of dendritic particle aggregation phenomena. The physical and chemical properties of systems in which DLA aggregates emerge are given in their fractal. In this paper, we present a comprehensive study of the growth of electrodeposited copper dendrites in flat plate electrochemical cells from a fractal perspective. The effects of growth time, applied voltage, copper ion concentration, and electrolyte acidity on the morphology and fractal dimension of deposited copper were examined. 'Phase diagram' set out the variety of electrodeposited copper fractal morphology analysed by metallographic microscopy. The box counting method confirms that the electrodeposited dendritic structures manifestly exhibit fractal character. It was found that with the increase of the voltage and copper ion concentration. The fractal copper size becomes larger and its morphology shifts towards a dendritic structure, with the fractal dimension fluctuating around 1.60-1.70. In addition, the morphology of the deposited copper is significantly affected by the acidity of the electrolyte. The increase in acidity from 0.01 to 1.00 mol/L intensifies the hydrogen precipitation side reactions and the overflow path of hydrogen bubbles affects the fractal growth of copper dendrites.

Effect of different abrasive grain sizes of the diamond grinding wheel on the surface characteristics of GaN

  • Joo Hyung Lee;Seung Hoon Lee;Hee Ae Lee;Nuri Oh;Sung Chul Yi;Jae Hwa Park
    • Journal of Ceramic Processing Research
    • /
    • v.23 no.4
    • /
    • pp.436-442
    • /
    • 2022
  • Gallium nitride (GaN) substrates were ground in two different grinding wheel abrasive sizes of 270 and 800-mesh, and thechange in surface morphologies of the substrates and the depth of subsurface damage (SSD) were observed. With the 800-meshgrinding wheel, the surface roughness (SR) and the depth of SSD of the sample tended to decrease, which was not the casewith the 270-mesh grinding wheel. In the X-ray rocking curve, the sample exhibited some compressive stress with the 270-meshgrinding wheel, but with the 800-mesh grinding wheel, it demonstrated the occurrence of tensile stresses in the sample and adecrease in full width at half maximum (FWHM), which confirms an improvement in the crystallinity. In the Raman spectra,the compressive stress of the 270-mesh grinding wheel and the tensile stress of the 800-mesh grinding wheel were confirmedthrough peak shifts. Photoluminescence (PL) spectra confirmed that the intensity ratio of the yellow luminescence increasedat the 800-mesh grinding wheel, and a blue shift occurred further. These results indicate that the SR and the depth of SSDwere proportional to the abrasive grain size of the grinding wheel. At the same time, the increase in PL intensity at specificpeak positions indicates that the stress stemming from the grinding process was concentrated at the crystal surface. The abovemechanism is illustrated in a schematic diagram, which confirms the possibility of improving the grinding efficiency andsubsequent polishing processes in future applications.

Effect of Relative Humidity on the Atmospheric Corrosion of Mild Steel Using the Electrochemical Wet/Dry Method (전기화학적 wet/dry 법을 이용한 탄소강의 대기부식에 미치는 상대습도의 영향에 관한 연구)

  • Yeon Jei-Won;Pyun Su-Il;Lee Woo-Jin;Choi In-Kyu;Chun Kwan-Sik
    • Journal of the Korean Electrochemical Society
    • /
    • v.3 no.1
    • /
    • pp.5-10
    • /
    • 2000
  • In the present work, corrosion rate W and corrosion potential tow were simultaneously measured as a function of relative humidity RH employing the electrochemical wet and dry method as an accelelated atmospheric corrosion method. The W versus (vs.) RH curve is classified into .three regions, namely, the first W plateau region, the second region of the linear relationship between logarithmic W and RH, finally, followed by an abrupt decay region. Based upon the atmospheric corrosion mechanism of mild steel, we introduced another diagram of $\varepsilon_{corr}$ vs. RH which is divided into three regions. In the first region, the corrosion scales are composed of single lepidocrocite-phase $(\gamma-FeOOH)$; in the second region, $\gamma-FeOOH$-phase coexists with magnetite-phase $(Fe_3O_4)$ in the scales and finally the oxide scales change into a single Fe304-phase in the third region. The three distinct regions of both representations share almost each other, which is validated by FT-IR (Fourier transform infra-red) analysis and surface observation. Both representations prove to be convenient and complementary for surveying the spectrum of the atmospheric corrosion of mild steel.

Dynamic Behavior Study Using Videomicroscopy in Systems Containing Polar Oils and Nonionic Surfactant (극성 오일, 비이온성 계면활성제를 포함한 계에서의 Videomicroscopy를 이용한 동적 거동에 관한 연구)

  • Lim, Jong-Choo
    • Applied Chemistry for Engineering
    • /
    • v.8 no.3
    • /
    • pp.473-481
    • /
    • 1997
  • Enhanced videomicroscopy was used to observe the dynamic behavior which occurred when water containing pure nonionic surfactant was carefully contacted with equal volumes of polar oils such as oleyl alcohol and oleic acid at various temperatures. A key component of the system is a vertical-stage microscope which provides for stable interfaces by locating the oil above the denser aqueous phase. This arrangement allowed intermediate phases formed at the surface of contact to be clearly observed, as well as any spontaneous emulsification which developed. Contacting experiments with $C_{12}E_5$ as the surfactant and with pure oleyl alcohol and oleic acid soils showed little activity below the cloud point but vigorous activity at higher temperatures including formation of an intermediate lamellar liquid crystalline phase. Diffusion path theory, which allows prediction of spontaneous emulsification resulting from diffusion and of intermediate phase formation during contacting processes, was used to understand the dynamic behavior seen during contacting experiments. Tentative diffusion paths for the contacting experiments with pure oleyl alcohol were presented with the aid of a partial phase diagram of the oleyl alcohol-water-$C_{12}E_5$ system.

  • PDF

A Study on Rhythm Information Visualization Using Syllable of Digital Text (디지털 텍스트의 음절을 이용한 운율 정보 시각화에 관한 연구)

  • Park, seon-hee;Lee, jae-joong;Park, jin-wan
    • Proceedings of the Korea Contents Association Conference
    • /
    • 2009.05a
    • /
    • pp.120-126
    • /
    • 2009
  • As the information age grows rapidly, the amount of digital texts has been increasing as well. It has brought an increasing of visualization case in order to figure out lots of digital texts. Existing visualized design of digital text is merely concentrating on figuration of subject word through adoption of stemming algorithm and word frequency extraction, prominence of meaning of text, and connection in between sentences. So it is a fact that expression of rhythm that can visualize sentimental feeing of digital text was insufficient. Syllable is a phoneme unit that can express rhythm more efficiently. In sentences, syllable is a most basic pronunciation unit in pronouncing word, phase and sentence. On this basis, accent, intonation, length of rhythm factor and others are based on syllable. Sonority, which is most closely associated with definitions of syllable, is expressed through air flow of igniting lung and acoustic energy that is specified kinetic energy into sonority. Seen from this perspective, this study examines phonologic definition and characteristics based on syllable, which is properties of digital text, and research the way to visualize rhythm through diagram. After converting digital text into phonetic symbol by the experiment, rhythm information are visualized into images using degree of resonance, which was started from rhythm in all languages, and using syllable establishment of digital text. By visualizing syllable information, it provides syllable information of digital text and express sentiment of digital text through diagram to assist user's understanding by systematic formula. Therefore, this study is aimed at planning for easy understanding of text's rhythm and realizing visualization of digital text.

  • PDF

Electrochemical Study on Transfer Reaction of Ionizable Cefotiam across a Water/1,2-dichloroethane Interface and Drug Sensing Applications (물/1,2-Dichloroethane 계면에서 Cefotiam 약물 이온의 전이 반응 연구 및 약물 센서에 응용)

  • Liu, XiaoYun;Jeshycka, Shinta;Lee, Hye Jin
    • Applied Chemistry for Engineering
    • /
    • v.29 no.5
    • /
    • pp.581-588
    • /
    • 2018
  • In this article, electrochemical investigation of the transfer reaction of ionizable cefotiam (CTM), an antibiotic molecule across a polarized water/1,2-dichloroethane (water/1,2-DCE) interface was studied. Ion partition diagram providing the preferred charged form of CTM in either water or 1,2-DCE phase was established via the voltammetric evaluation of the transfer process of differently charged CTM species depending upon the pH variation of aqueous solutions. Thermodynamic information including the formal transfer potential and formal Gibbs transfer energy values in addition to important pharmacokinetics including partition coefficients of ionizable CTM were also evaluated. In particular, the current associated with the transfer of CTM present at pH 3.0 aqueous solution proportionally increased with respect to the CTM concentration which was further used for developing CTM sensitive ion sensor. In order to improve the portability and convenient usage, a single microhole interface fabricated in a supportive polyethylene terephthalate film was used of which hole was filled with a polyvinylchloride-2-nitrophenyloctylether (PVC-NPOE) gel replacing 1,2-DCE, a toxic organic solvent. A dynamic range of $1-10{\mu}M$ CTM was obtained.

Determination of Hydroxyapatite Precipitation Condition from the $Ca-PO_4-H_2O$ System ($Ca-PO_4-H_2O$계로부터 수산화아파타이트의 침전조건 결정)

  • Oh, Young-Jei
    • Analytical Science and Technology
    • /
    • v.13 no.2
    • /
    • pp.208-214
    • /
    • 2000
  • The formation and dissolution of hydroxides, carbonates and hydroxyapatite (HAp), which depend on the pH of solution, are important factor for the preparation of homogeneous and fine HAp, $Ca_{10-x}(HPO_4)_x(PO_4)_{6-x}(OH)_{2-x}(x=0)$, ceramic powder from the $Ca-PO_4-H_2O$ system. Since the solubility of each complex ion is a linear function of pH, the solubility diagram can be obtained by plotting the logarithmic molar concentrations calculated from the values of the equilibrium constants and solubility products for hydroxides, carbonates, and hydroxyapatite. The optimum pH condition for the formation of single phase $Ca_{10-x}(HPO_4)_x(PO_4)_{6-x}(OH)_{2-x}(x=0)$ powder in $Ca-PO_4-H_2O$ system at $25^{\circ}C$ was estimated as $10.5{\pm}0.5$ through the theoretical consideration. The HAp powder dried at $80^{\circ}C$ showed a fine agglomerated particles with a size of 75 nm. The HAp powder calcined at $1,000^{\circ}C$ consisted of nearly homogeneous particles with a size of 450 nm. Even though the dried HAp particles consisted of agglomeration, mechanical properties were superior due to fine microstructure after sintering.

  • PDF