생활환경 및 직업환경 노출 유해인자의 면역독성 평가 대체시험법 개발

Acharya Manju(Acharya Manju ),Maharjan Anju(Maharjan Anju ),Lee DaEun(DaEun Lee),K C Pramod(K C Pramod ),Kusma Sarina(Kusma Sarina ),Adhikari Manisha(Adhikari Manisha ),Kim ChangYul(ChangYul Kim),Kim 한국환경보건학회 2022 한국환경보건학회 학술대회 자료집 Vol.2022 No.5

Numerical analysis and performance enhancement of a cross-flow hydro turbine

Acharya, Nirmal,Kim, Chang-Gu,Thapa, Bhola,Lee, Young-Ho Elsevier 2015 RENEWABLE ENERGY Vol.80 No.-

<P><B>Abstract</B></P> <P>Exploitation of small hydropower sources requires the use of small turbines that combine efficiency and economy which can conveniently cater the power needs of rural and small communities. Cross-flow turbines are used widely in such micro hydropower plants due to their simple design, easier maintenance, low initial investment and modest efficiency. Also, because of their suitability under low heads, their efficient operation under a wide range of flow variations and ease of fabrication, cross-flow turbines have been extensively employed. The primary objective of this study is to numerically analyze the characteristics and the fluid flow in a cross-flow hydro turbine and to optimize its performance by geometrically modifying the several parameters. During the process, a base model was chosen, the design was modified simultaneously by varying the nozzle shape, changing the guide vane angle, varying the number of runner blades and simulations were carried out individually. Two phase (air & water at 25 °C), steady state with SST turbulence model was selected in the commercial CFD code ANSYS CFX 13.0 for the numerical simulation. The design parameters included 10 m head, 0.1 m<SUP>3</SUP>/s flow rate and 642 rpm rotational speed. The results obtained showed that the best efficiency obtained from the base nozzle was 63.67% which was geometrically modified that improved the turbine performance and the efficiency reached 76.60% (increase by 12.93%). Velocity distribution, pressure contours, output torque within the flow domain were also characterized. It was observed that the re-circulating flow region was reduced and also its pattern was varied.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Efficiency of the turbine increases from 63.67% (base model) to 67.26% (nozzle modified with 150 mm radius of edge). </LI> <LI> Varying the guide vane angle increases the efficiency from 67.26% to 73.09% (7° GV angle). </LI> <LI> Changing number of runner blades gives the highest efficiency of 76.60% with 22 number of blades, 30 being the number of blades for base model. </LI> <LI> Re-circulation zones are observed inside the nozzle and runner interior part, which might be one of the reason for low efficiency of cross-flow turbines. </LI> </UL> </P>

GUNS AND BUTTER : WHY DO HUMAN SECURITY AND TRADITIONAL SECURITY CO-EXIST IN ASIA?

Acharya, Amitav 연세대학교 동서문제연구원 2003 Global economic review Vol.32 No.3

This paper examines the concept of human security as it applies to Asia, in challenging the dominance of the national security paradigm in Asia. To understand the concept of human security, we may combine the interdependent understandings of freedom from fear, freedom from want, and freedom from suffering in times of conflict. To make the distinction between human security and national security, we may highlight the following three important questions: whose security, security against what, and security in which areas.

Influence of Nanodispersed Organoclay on Rheological and Swelling Properties of Ethylene Propylene Diene Terpolymer

Acharya Himadri,Srivastava Suneel K. The Polymer Society of Korea 2006 Macromolecular Research Vol.14 No.2

The dispersion of organoclay in ethylene propylene diene terpolymer (EPDM) matrix was correlated with the rheological and swelling properties of nanocomposites. X-ray diffraction pattern (XRD) and transmission electron microscopic (TEM) analysis exhibited the disordered-intercalated structure of EPDM/organoclay nanocomposite. The extent of the disordered phase increased with increasing organoclay content up to a limiting value of 3 wt% after which equilibrium tended towards intercalation. The dispersion effect of organoclay in EPDM matrix was clarified by the physicochemical properties like rheological response and swelling thermodynamics in toluene. The increase in viscoelastic properties of EPDM nanocomposite with increasing organoclay content up to 3 wt%, followed by a subsequent decrease up to 4 wt%, was correlated in terms of the disordered and ordered states of the dispersed nano-clay sheets. Swelling measurements revealed that the change in entropy of the swelling increased with the increase in disorder level but decreased with the increase in intercalation level of organoclay in the disordered-intercalated nanocomposite. The increase in solvent uptake was comparable with the free volume in EPDM matrix upon inclusion of silicate particles, whereas the inhibition in solvent uptake for higher organoclay loading was described by bridging flocculation.

Hormone Therapy and Delivery Strategies against Cardiovascular Diseases

Acharya, Gayathri,Hasan, Nurhasni,Yoo, Jin-Wook,H. Lee, Chi Bentham Science Publishers Ltd. 2017 CURRENT PHARMACEUTICAL BIOTECHNOLOGY Vol. No.

Production of [FORMULA OMISSION] and [FORMULA OMISSION] mesons up to high transverse momentum in pp collisions at 2.76 TeV

Acharya, S.,Adamová,, D.,Aggarwal, M. M.,Rinella, G. Aglieri,Agnello, M.,Agrawal, N.,Ahammed, Z.,Ahmad, N.,Ahn, S. U.,Aiola, S.,Akindinov, A.,Alam, S. N.,Albuquerque, D. S. D.,Aleksandrov, D.,Al Springer 2017 European Physical Journal C Vol.77 No.5

<P>The invariant differential cross sections for inclusive [FORMULA OMISSION] and [FORMULA OMISSION] mesons at midrapidity were measured in pp collisions at [FORMULA OMISSION] TeV for transverse momenta [FORMULA OMISSION] GeV/<I>c</I> and [FORMULA OMISSION] GeV/<I>c</I>, respectively, using the ALICE detector. This large range in [FORMULA OMISSION] was achieved by combining various analysis techniques and different triggers involving the electromagnetic calorimeter (EMCal). In particular, a new single-cluster, shower-shape based method was developed for the identification of high-[FORMULA OMISSION] neutral pions, which exploits that the showers originating from their decay photons overlap in the EMCal. Above 4 GeV/[FORMULA OMISSION], the measured cross sections are found to exhibit a similar power-law behavior with an exponent of about 6.3. Next-to-leading-order perturbative QCD calculations differ from the measured cross sections by about 30% for the [FORMULA OMISSION], and between 30–50% for the [FORMULA OMISSION] meson, while generator-level simulations with PYTHIA 8.2 describe the data to better than 10–30%, except at [FORMULA OMISSION] GeV/[FORMULA OMISSION]. The new data can therefore be used to further improve the theoretical description of [FORMULA OMISSION] and [FORMULA OMISSION] meson production.</P>

Energy dependence of forward-rapidity [FORMULA OMISSION] and [FORMULA OMISSION] production in pp collisions at the LHC

Acharya, S.,Adamová,, D.,Aggarwal, M. M.,Aglieri Rinella, G.,Agnello, M.,Agrawal, N.,Ahammed, Z.,Ahmad, N.,Ahn, S. U.,Aiola, S.,Akindinov, A.,Alam, S. N.,Albuquerque, D. S. D.,Aleksandrov, D.,Al Springer 2017 European Physical Journal C Vol.77 No.6

<P>We present results on transverse momentum ([FORMULA OMISSION]) and rapidity ([FORMULA OMISSION]) differential production cross sections, mean transverse momentum and mean transverse momentum square of inclusive [FORMULA OMISSION] and [FORMULA OMISSION] at forward rapidity ([FORMULA OMISSION]) as well as [FORMULA OMISSION]-to-[FORMULA OMISSION] cross section ratios. These quantities are measured in pp collisions at center of mass energies [FORMULA OMISSION] and 13 TeV with the ALICE detector. Both charmonium states are reconstructed in the dimuon decay channel, using the muon spectrometer. A comprehensive comparison to inclusive charmonium cross sections measured at [FORMULA OMISSION], 7 and 8 TeV is performed. A comparison to non-relativistic quantum chromodynamics and fixed-order next-to-leading logarithm calculations, which describe prompt and non-prompt charmonium production respectively, is also presented. A good description of the data is obtained over the full [FORMULA OMISSION] range, provided that both contributions are summed. In particular, it is found that for [FORMULA OMISSION] GeV/<I>c</I> the non-prompt contribution reaches up to 50% of the total charmonium yield.</P>

Land Cover Classification of Imagery from Landsat Operational Land Imager Based on Optimum Index Factor

Acharya, Tri Dev,Yang, In Tae,Lee, Dong Ha MYU K.K. 2018 Sensors and materials Vol.30 No.8

<P>With over four decades spent collecting spaceborne moderate-resolution imagery, Landsat represents the longest remote sensing mission in the world, and has had various applications. Land cover mapping is its heritage for research around the world. Landsat 8 continues the legacy of previous Landsat systems, with a new Operational Land Imager (OLI) sensor that has high spectral resolution and improved signal-to-noise ratio for better characterization of land cover. With improved quality, data size also increases. Hence, with limited research in adjusting data size, it is necessary to explore robust land cover classification techniques that produce accurate maps with more or fewer inputs. The Optimum Index Factor (OIF) is a statistic value that can be used to select the optimum combination of three bands in a satellite image that has the highest amount of information. In this study, we explore the land cover classification of OLI imagery based on OIF. Two test sites were selected around the hilly regions of Korea for OLI original composite, first-rank OIF composite, and OLI original with sum derivative of top-three OIF ranked composites. These three composites were classified with the well-known Spectral Angle Mapper (SAM) and Support Vector Machine (SVM) classifiers. The results were then analyzed and compared on the basis of producer accuracy, user accuracy, overall accuracy, and kappa coefficient. The result shows that the first-ranked OIF with a three-band composite shows a similar classification accuracy in SVM and slightly less in SAM, while the ten-band composite with OLI original bands and the sum derivative of the top-three OIF rank shows the same result or a small improvement in SVM classification. OIF-derivative composites can be useful in classification problems depending on whether the minimum amount of data for a similar result or more data to achieve higher accuracy is preferred.</P>

Linear and non-linear flow mode in Pb–Pb collisions at _{s NN} = 2.76 TeV

Acharya, S.,Adamová,, D.,Adolfsson, J.,Aggarwal, M.M.,Aglieri Rinella, G.,Agnello, M.,Agrawal, N.,Ahammed, Z.,Ahmad, N.,Ahn, S.U.,Aiola, S.,Akindinov, A.,Alam, S.N.,Alba, J.L.B.,Albuquerque, D.S North-Holland Pub. Co 2017 Physics letters. Section B Vol.773 No.-

<P><B>Abstract</B></P> <P>The second and the third order anisotropic flow, <SUB> V 2 </SUB> and <SUB> V 3 </SUB> , are mostly determined by the corresponding initial spatial anisotropy coefficients, <SUB> ε 2 </SUB> and <SUB> ε 3 </SUB> , in the initial density distribution. In addition to their dependence on the same order initial anisotropy coefficient, higher order anisotropic flow, <SUB> V n </SUB> ( n > 3 ), can also have a significant contribution from lower order initial anisotropy coefficients, which leads to mode-coupling effects. In this Letter we investigate the linear and non-linear modes in higher order anisotropic flow <SUB> V n </SUB> for n = 4 , 5, 6 with the ALICE detector at the Large Hadron Collider. The measurements are done for particles in the pseudorapidity range | η | < 0.8 and the transverse momentum range 0.2 < <SUB> p T </SUB> < 5.0 GeV / c as a function of collision centrality. The results are compared with theoretical calculations and provide important constraints on the initial conditions, including initial spatial geometry and its fluctuations, as well as the ratio of the shear viscosity to entropy density of the produced system.</P>

Longitudinal asymmetry and its effect on pseudorapidity distributions in Pb–Pb collisions at _{s NN} = 2.76 TeV

Acharya, S.,Adam, J.,Adamová,, D.,Adolfsson, J.,Aggarwal, M.M.,Aglieri Rinella, G.,Agnello, M.,Agrawal, N.,Ahammed, Z.,Ahmad, N.,Ahn, S.U.,Aiola, S.,Akindinov, A.,Al-Turany, M.,Alam, S.N.,Alba, Elsevier 2018 Physics letters: B Vol.781 No.-

<P><B>Abstract</B></P> <P>First results on the longitudinal asymmetry and its effect on the pseudorapidity distributions in Pb–Pb collisions at <SUB> s NN </SUB> = 2.76 TeV at the Large Hadron Collider are obtained with the ALICE detector. The longitudinal asymmetry arises because of an unequal number of participating nucleons from the two colliding nuclei, and is estimated for each event by measuring the energy in the forward neutron-Zero-Degree-Calorimeters (ZNs). The effect of the longitudinal asymmetry is measured on the pseudorapidity distributions of charged particles in the regions | η | < 0.9 , 2.8 < η < 5.1 and − 3.7 < η < − 1.7 by taking the ratio of the pseudorapidity distributions from events corresponding to different regions of asymmetry. The coefficients of a polynomial fit to the ratio characterise the effect of the asymmetry. A Monte Carlo simulation using a Glauber model for the colliding nuclei is tuned to reproduce the spectrum in the ZNs and provides a relation between the measurable longitudinal asymmetry and the shift in the rapidity ( <SUB> y 0 </SUB> ) of the participant zone formed by the unequal number of participating nucleons. The dependence of the coefficient of the linear term in the polynomial expansion, <SUB> c 1 </SUB> , on the mean value of <SUB> y 0 </SUB> is investigated.</P>