• Title/Summary/Keyword: Asymmetric Effect

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CFD Analysis on Effect of Pressure Drop and Flow Uniformity with Geometry in 13" Asymmetric DPF (13" 비대칭 DPF 내 형상에 따른 배압 및 유동균일도 영향에 관한 전산해석연구)

  • HAN, DANBEE;BYUN, HYUNSEUNG;BAEK, YOUNGSOON
    • Transactions of the Korean hydrogen and new energy society
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    • v.31 no.6
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    • pp.614-621
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    • 2020
  • Recently, as the fine dust is increased and the emission regulations of diesel engines are strengthened, interest in diesel soot filtration devices is rapidly increased. In particular, there is a demand for technology development for higher efficiency of diesel exhaust gas after-treatment devices. As part of this, many studies conducted to increase the exhaust gas treatment efficiency by improving the flow uniformity of the exhaust gas in the DPF and reducing the pressure drop between the inlet and outlet of disel particle filter (DPF). In this study, computational fluid dynamics (CFD) simulation was performed when exhaust gas flows into the canning reduction device equipped with a 13" asymmetric DPF in order to maintain the flow uniformity in the diesel exhaust system and reduce the pressure. In particular, a study was conducted to find the geometry with the smallest pressure drop and the highest flow uniformity by simulating the DPF I/O ratio, exhaust gas temperature, inlet-outlet pressure and flow uniformity according to the geometry and hole size of distributor.

The Role of Remittances in Financial Development: Evidence from Nonlinear ARDL and Asymmetric Causality

  • MEHTA, Ahmed Muneeb;QAMRUZZAMAN, Md.;SERFRAZ, Ayesha;ALI, Asad
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.3
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    • pp.139-154
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    • 2021
  • This study's impetus is to explore fresh evidence to answer the question, i.e., whether remittances asymmetrically influence financial development in Bangladesh from 1975 to 2019. The study employs several tests, i.e., nonlinear unit root test, Autoregressive Distributed Lagged (ARDL), NARDL, and asymmetric causality test for establishing the pattern of association. Nonlinear unit root tests confirm that variables follow a nonlinear system of being stationary after the first difference. nonlinearity among variables is investigated by performing the BDS test and nonlinear OLS. Directional causality is investigated through both linear and nonlinear effects of remittance inflows by following the non-granger casualty test. The test statistics of Fpass and tBDM showed the Long-run cointegration in the empirical model and positive effect running from remittances inflow to financial development both in the long-run and short-run. Furthermore, the results of a standard Wald test divulge the presence of long-run and short-run asymmetry. Asymmetry causality test established unidirectional causality due to positive and negative shocks in remittances inflows to Bank-based financial development and feedback hypothesis hold for explaining causality between positive and negative shocks in remittance inflows and Stock-based financial development.

Nonlinear Effects of Remittances Paid on Macroeconomics in Malaysia

  • TAASIM, Shairil Izwan
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.2
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    • pp.783-790
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    • 2021
  • The remittances play a major and a very critical role in promoting economic growth and development activities in the developing countries. In this study, the relationship between per capita gross domestic product (GDP) and remittances paid has been investigated based on the case studies in Malaysia from 1987 to 2018. Data was collected from various sources namely statistical yearbook by World Bank and Asian Development Bank. All variables are expressed in natural logarithm form. The technique utilized is the nonlinear autoregressive distributed lags (hereafter NARDL) approach which was introduced by Shin et al.(2014) to examine both short run and long run relationships, as well as the direction of causality, due to the asymmetric relationship between GDP and remittances. The bound test verifies asymmetric cointegration among the variables. The empirical results show that the remittances paid has a momentous short-run and long-run effect towards capital accumulation in Malaysia. Remittances also increase a positive relationship with capital accumulation for Malaysia. We found that remittances form a significant source of external capital and investment for developing countries especially Malaysia which helps in promoting economic development. Furthermore, as a developing country, foreign workers are a source of income to the receiving countries and an indicator to boost sender countries.

Dynamic vibration response of functionally graded porous nanoplates in thermal and magnetic fields under moving load

  • Ismail Esen;Mashhour A. Alazwari;Khalid H. Almitani;Mohamed A Eltaher;A. Abdelrahman
    • Advances in nano research
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    • v.14 no.5
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    • pp.475-493
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    • 2023
  • In the context of nonclassical nonlocal strain gradient elasticity, this article studies the free and forced responses of functionally graded material (FGM) porous nanoplates exposed to thermal and magnetic fields under a moving load. The developed mathematical model includes shear deformation, size-scale, miscorstructure influences in the framework of higher order shear deformation theory (HSDT) and nonlocal strain gradient theory (NSGT), respectively. To explore the porosity effect, the study considers four different porosity models across the thickness: uniform, symmetrical, asymmetric bottom, and asymmetric top distributions. The system of quations of motion of the FGM porous nanoplate, including the effects of thermal load, Lorentz force, due to the magnetic field and moving load, are derived using the Hamilton's principle, and then solved analytically by employing the Navier method. For the free and forced responses of the nanoplate, the effects of nonlocal elasticity, strain gradient elasticity, temperature rise, magnetic field intensity, porosity volume fraction, and porosity distribution are analyzed. It is found that the forced vibrations of FGM porous nanoplates under thermal and live loads can be damped by applying a directed magnetic field.

Asymmetric Metal-Semiconductor-Metal Al0.24Ga0.76N UV Sensors with Surface Passivation Effect Under Local Joule Heating

  • Byeong-Jun Park;Sung-Ho Hahm
    • Journal of Sensor Science and Technology
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    • v.32 no.6
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    • pp.425-431
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    • 2023
  • An asymmetric metal-semiconductor-metal Al0.24Ga0.76N ultraviolet (UV) sensor was fabricated, and the effects of local Joule heating were investigated. After dielectric breakdown, the current density under a reverse bias of 2.0 V was 1.1×10-9 A/cm2, significantly lower than 1.2×10-8 A/cm2 before dielectric breakdown; moreover, the Schottky behavior of the Ti/Al/Ni/Au electrode changed to ohmic behavior under forward bias. The UV-to-visible rejection ratio (UVRR) under a reverse bias of 7.0 V before dielectric breakdown was 87; however, this UVRR significantly increased to 578, in addition to providing highly reliable responsivity. Transmission electron microscopy revealed interdiffusion between adjacent layers, with nitrogen vacancies possibly formed owing to local Joule heating at the AlGaN/Ti/Al/Ni/Au interfaces. X-ray photoelectron microscopy results revealed decreases in the peak intensities of the O 1s binding energies associated with the Ga-O bond and OH-, which act as electron-trapping states on the AlGaN surface. The reduction in dark current owing to the proposed local heating method is expected to increase the sensing performance of UV optoelectronic integrated devices, such as active-pixel UV image sensors.

Optimal design of seismic reinforcement for structures with asymmetric rigidity plans using genetic algorithm (유전자 알고리즘을 이용한 비대칭 강성 구조물의 내진보강 최적설계)

  • Lee, Joon-Ho;Kim, Yu-Seong;Sung, Eun-Hee
    • Journal of Korean Association for Spatial Structures
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    • v.24 no.2
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    • pp.65-73
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    • 2024
  • In this study, we propose an optimal design method by applying the Prefabricated Buckling Restrained Brace (PF-BRB) to structures with asymmetrically rigidity plan. As a result of the PF-BRB optimal design of a structure with an asymmetrically rigidity plan, it can be seen that the reduction effect of dynamic response is greater in the case of arrangement considering the asymmetric distribution of stiffness (Asym) than in the case of arrangement in the form of a symmetric distribution (Sym), especially It was confirmed that at an eccentricity rate of 20%, the total amount of reinforced PF-BRBs was also small. As a result of analyzing the dynamic response characteristics according to the change in eccentricity of the asymmetrically rigidity plan, the distribution of the reinforced PF-BRB showed that the larger the eccentricity, the greater the amount of damper distribution around the eccentric position. Additionally, when comparing the analysis models with an eccentricity rate of 20% and an eccentricity rate of 12%, the response reduction ratio of the 20% eccentricity rate was found to be large.

Fabrication and Characteristization of AlGaAs/InGaAs/GaAs Heterostructure Quantum-Wire FET (AlGaAs/InGaAs/GaAs 이종접합 양자선-FET의 제작 및 특성)

  • 손영진;이봉훈;정문영;정윤하
    • Proceedings of the IEEK Conference
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    • 2000.11b
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    • pp.13-16
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    • 2000
  • A quantum-wire field effect transistor(QW-FET) using asymmetric double InGaAs channel and Si-delta doped barrier has been fabricated. It exhibited good modulation and saturation characteristic in the range of ${\mu}\textrm{A}$ current level. For estimated channel width of 150nm QW-FET, maximum transconductance was about 400 mS/mm which is higher than a conventional heterostructure FET(HFET) with the same epi-structure.

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Texture of Asymmetrically Rolled AA 3003 Aluminum alloy (비대칭 압연한 AA 3003 합금의 조직 변화)

  • Akramov, S.;Kim, I.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2007.10a
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    • pp.332-333
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    • 2007
  • The effect of asymmetric rolling on the recrystallization texture of an AA 3003 Aluminum alloy was investigated by X-ray diffraction. It was found that the texture of asymmetrically rolled sheets prior to subsequent heat treatment promoted the formation of the <111>//ND textures, and remained after heat treatment at $275^{\circ}C$ during 20 min in salt bath condition.

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