Numerical and experimental validation for effective cross-sections in pulse detonation engine design

S. Srikrishnan,T. Shaafi,P.K. Dash 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.5

Industrial revolution and economic growth in any country is aided and abetted by effective defense research and developmenthand in hand with medical supremacy across the globe. Advent avionics system and advanced defense technology have sprungup from various nations further driving the need for hypersonic speed propulsion systems in transport or military applications. Pulse detonation systems may be an effective cure for such insolvency and may be used as an advanced highspeed propulsionsystem for various applications. The research work discusses the effect of cross-sections like cylinder, square and rectangle inachieving controlled detonation with supersonic velocity at exit and effective pressure for further expansion. The analysisresulted that the cylindrical cross-section with an orifice type blockage at three locations evenly spread throughout the lengthof the tube with 60 percent blockage ratio to be the most effective with maximum exit velocity of 2995.6 m/s and effectivepressure of 10.5 bar for an injection pressure of 100 bar and velocity 0.15 m/s. An experimental model using cold flow wasconducted to ratify the results from the numerical simulation and found to be similar with a differentiation of 14% due to thevariation of the working fluid.

Search for CP Violation and Measurement of the Branching Fraction in the Decay D0→KS0KS0

Dash, N.,Bahinipati, S.,Bhardwaj, V.,Trabelsi, K.,Adachi, I.,Aihara, H.,Al Said, S.,Asner, D. M.,Aulchenko, V.,Aushev, T.,Ayad, R.,Babu, V.,Badhrees, I.,Bakich, A. M.,Bansal, V.,Barberio, E.,Bhuyan, B American Physical Society 2017 Physical review letters Vol.119 No.17

<P>We report a study of the decay D-0 -> (KSKS0)-K-0 using 921 fb(-1) of data collected at or near the (sic)(4S) and (sic)(5S) resonances with the Belle detector at the KEKB asymmetric energy e(+)e(-) collider. The measured time-integrated CP asymmetry is A(CP)(D-0 -> (KSKS0)-K-0) = (-0.02 +/- 1.53 +/- 0.02 +/- 0.17)%, and the branching fraction is B(D-0 -> (KSKS0)-K-0) = (1.321 +/- 0.023 +/- 0.036 +/- 0.044) x 10(-4), where the first uncertainty is statistical, the second is systematic, and the third is due to the normalization mode (D-0 -> K-S(0)pi(0)). These results are significantly more precise than previous measurements available for this mode. The A(CP) measurement is consistent with the standard model expectation.</P>

Brownmillerite thin films as fast ion conductors for ultimate-performance resistance switching memory

Acharya, S.,Jo, J.,Raveendra, N.,Dash, U.,Kim, M.,Baik, H.,Lee, S.,Park, B.,Lee, J.,Chae, S. Royal Society of Chemistry 2017 Nanoscale Vol.9 No.29

Winkler Springs (p-y curves) for pile design from stress-strain of soils: FE assessment of scaling coefficients using the Mobilized Strength Design concept

Bouzid, Dj. Amar,Bhattacharya, S.,Dash, S.R. Techno-Press 2013 Geomechanics & engineering Vol.5 No.5

In practice, analysis of laterally loaded piles is carried out using beams on non-linear Winkler springs model (often known as p-y method) due to its simplicity, low computational cost and the ability to model layered soils. In this approach, soil-pile interaction along the depth is characterized by a set of discrete non-linear springs represented by p-y curves where p is the pressure on the soil that causes a relative deformation of y. p-y curves are usually constructed based on semi-empirical correlations. In order to construct API/DNV proposed p-y curve for clay, one needs two values from the monotonic stress-strain test results i.e., undrained strength ($s_u$) and the strain at 50% yield stress (${\varepsilon}_{50}$). This approach may ignore various features for a particular soil which may lead to un-conservative or over-conservative design as not all the data points in the stress-strain relation are used. However, with the increasing ability to simulate soil-structure interaction problems using highly developed computers, the trend has shifted towards a more theoretically sound basis. In this paper, principles of Mobilized Strength Design (MSD) concept is used to construct a continuous p-y curves from experimentally obtained stress-strain relationship of the soil. In the method, the stress-strain graph is scaled by two coefficient $N_C$ (for stress) and $M_C$ (for strain) to obtain the p-y curves. $M_C$ and $N_C$ are derived based on Semi-Analytical Finite Element approach exploiting the axial symmetry where a pile is modelled as a series of embedded discs. An example is considered to show the application of the methodology.

Synthesis and Characterization of Homobinuclear Complexes of UO_2(VI), Th(IV), ZrO(IV) and VO(IV) with Schiff-Base Monohydrazone Derivatives

Dash, D.C.,Mohapatra, R.K.,Ghosh, S.,Naik , P. Korean Chemical Society 2008 대한화학회지 Vol.52 No.5

Effect of Ichnocarpus frutescens extract on antihyperglycemic, antihyperlipidemic and antioxidant status in streptozotocin-induced diabetic rats

Dash, Deepak K,Ghosh, Tirtha,Yeligar, Veerendra C,Murugesh, K,Nayak, Siva S,Maiti, Bhim C,Maity, Tapan K Kyung Hee Oriental Medicine Research Center 2007 Oriental pharmacy and experimental medicine Vol.7 No.3

The present study was carried out to investigate the antihyperglycemic, antihyperlipidemic and antioxidant effect of chloroform and methanol extract of whole plant of Ichnocarpus frutescens (CEIF and MEIF) in streptozotocin (STZ)-induced diabetic rats. Administration of CEIF and MEIF orally at the dose of 200 mg/kg and 400 mg/kg body weight resulted in significant (P<0.01) reduction in blood glucose levels. The body weights were significantly (P<0.001) reduced in STZ-induced diabetic rats when compared to normal rats while the extracts significantly (P<0.01) prevented the decrease in body weight in the CEIF and MEIF treated rats. The study was further undertaken to evaluate the antioxidant and antihyperlipidemic potential of CEIF and MEIF in STZ-induced diabetic rats. The increased levels of lipid peroxidation in the liver tissues of diabetic rats were significantly reverted back to normal levels and a significant increase in activity of antioxidant enzymes such as superoxide dismutase, catalase and the level of reduced glutathione in the liver of diabetic rats after the treatment with CEIF and MEIF was noticed. These results clearly indicate that CEIF and MEIF exhibit significant antihyperglycemic, antihyperlipidemic and in vivo antioxidant activity in STZ-induced diabetic rats and the results were found to be in a dose dependent manner.

Inhibition of AP-1 by SARI negatively regulates transformation progression mediated by CCN1

Dash, R,Su, Z-Z,Lee, S-G,Azab, B,Boukerche, H,Sarkar, D,Fisher, P B Macmillan Publishers Limited 2010 Oncogene Vol.29 No.31

Enhanced expression of the CCN family of secretory integrin-binding proteins correlates with many essential components of the cancerous state, including tumor cell adhesion, proliferation, invasion and migration. Consequently, CCN1 expression is elevated in various cancers, including breast cancer, and its expression directly correlates with poor patient prognosis. Using subtraction–hybridization, combined with induction of cancer cell terminal differentiation, we cloned SARI (suppressor of activator protein (AP)-1, regulated by interferon (IFN)), an IFN-β-inducible, potent tumor suppressor gene that exerts cancer-selective growth inhibitory effects. Forced expression of SARI using an adenovirus (Ad.SARI) inhibits AP-1 function and downregulates CCN1 expression in multiple cancer lineages, resulting in a profound inhibition in anchorage-independent cell growth and tumor cell invasion. Overexpression of SARI reduces CCN1-promoter activity through inhibition of AP-1 binding. Accordingly, SARI selectively blocks expression of the transformed state in rat embryo fibroblast cells that stably overexpress c-Jun. These results illustrate that SARI inhibits AP-1 transactivating factor binding to the cis-element of the CCN1 promoter, possibly through its interaction with c-Jun. Overall, SARI can directly inhibit CCN1-induced transformation by inhibiting the transcription of CCN1, as well as indirectly by inhibiting the expression of c-Jun (and hence blocking AP-1 activity). In these contexts, transformed cells ‘addicted’ to AP-1 activity are rendered susceptible to SARI-mediated inhibition of expression of the transformed phenotype.

Encapsulation of 2-(4'-N,N-dimethylamino)phenylimidazo[4,5-b]pyridine in $\beta$-cyclodextrin: effect on H-bond-induced intramolecular charge transfer emission

Dash, Nihar,Chipem, Francis A.S.,Krishnamoorthy, G. Korean Society of Photoscience 2009 Photochemical & photobiological sciences Vol.8 No.12

The effect of $\beta$-cyclodextrin ($\beta$-CD) inclusion complex formation on the hydrogen bond-induced intramolecular charge transfer (ICT) of 2-(4'-N,N-dimethylamino)phenylimidazo[4,5-b]pyridine (DMAPIP-b) has been examined by fluorescence excitation, emission and time-resolved fluorescence techniques. The study reveals that DMAPIP-b forms 1 : 1 inclusion complex with $\beta$-CD. The host-guest complex is formed by partial inclusion of DMAPIP-b, i.e. only the dimethylaminophenyl ring is encapsulated inside the core of the $\beta$-CD nanocavity. The imidazopyridine ring of the guest molecule resides outside CD cavity and forms H-bonds with the water molecules that are present near the rim and in the bulk phase. $^1H$ NMR studies are used to confirm the inclusion complex. The H-bond of water with the pyridine nitrogen ensures the formation of the ICT state and both normal and ICT emissions are enhanced inside the $\beta$-CD cavity. Fluorescence lifetime measurements suggest that the formation of the ICT state from the locally excited state is irreversible. Dual emission is observed in the presence of $\beta$-CD at pH ~ 3.5, due to emission from monocations formed by the protonation of pyridine nitrogen (MC1) and imidazole nitrogen (MC2).

The dynamics of glassy behavior in SrRu1-Fe O3 heterostructure

Dash Umasankar,Pradhan Soumen,Rao M.S. Ramachandra,Veillon F.,Prellier W.,Jung Chang Uk 한국물리학회 2024 Current Applied Physics Vol.58 No.-

We report the magnetic interactions in SrRu1-xFexO3 epitaxial thin films. All the films showed a single-phase and good step-terrace structure with minimal surface roughness. The X-ray photoelectron spectra of Fe and Ru revealed that both transition metal elements exist in the films as Fe3+ and Ru4+. With Fe doping, the itinerant ferromagnetic behavior and ferromagnetic transition temperature gradually decreased, but the coercivity field increased. The magnetic interplay between Fe3+-O-Fe3+ is coined as antiferromagnetic. There was another interaction between Ru4+-O-Fe3+ which is best described as ferromagnetic. Furthermore, the magnetic frustration in our films caused by the doped Fe resulted in dynamic glassy behavior. On the other hand, the epitaxial strain from the imminent SrTiO3 substrate along with change in oxygen vacancy might have strong evidence for the spin-glass nature in our thin films.

Synthesis and Characterization of Homobinuclear Complexes of UO₂(VI), ZrO(IV) and Th(IV) ions with 3-Benzylidine/Furfurylidine/(Pyridyl/Thienyl-2'-methylene) imino-5-p-sulphonamido phenyl azo-2-thiohydantoins

Dash, D.C.,Mahapatra, A.,Naik, P.,Mohapatra, R.K.,Naik, S.K. Korean Chemical Society 2011 대한화학회지 Vol.55 No.3

[$M_2L(NO_3)_n(H_2O)_m$]의 일반식을 갖는 일련의 동종이핵 착물을 합성하여 원소분석, 열분석, 몰 전기전도도, 자기모멘트 및 분광학적 방법(IR, UV-vis 및 $^1H$-NMR)을 통해 특성을 조사하였다. 이 경우, 일반식에 있어서 M=$UO_2$(VI), ZrO(IV), Th(IV); L=3-benzylidine-imino-5-p-sulphonamido phenyl azo-2-thiohyatoin(bispt), 3-furfurylidine-imino-5-psulphonamido phenyl azo-2-thiohydantoin(fispt),3-pyridyl-2'-methylene-imino-5-p-sulphonamido phenyl azo-2-thiohydantoin (pmispt) 및 3-thienyl-2'-methylene-imino-5-p-sulphoanamido phenyl azo-2-thiohydantoin(tmispt); Th(IV)에 대해서 n=8 그 외의 것에 대해서는 n=4, bispt에 대해서는 m=4 그 외의 것에 대해서는 m=3을 의미한다. 이러한 결과에서 얻은 정보를 통해 리간드들은 4배위를 하는 것으로 확인되었는데, 즉 한 중심금속은azomethine 질소 및 카르보닐 산소에 배위되는 반면, 또 다른 중심금속은 아조 질소 및 thioimido 질소에 배위되어 위의 조성을 갖는 동종이핵 착물을 이룬다. 몇 가지 병원균에 대한 리간드와 그들의 지르코닐 착물의 독성 연구도 수행하였다. A series of homobinuclear complexes of the type [$M_2L(NO_3)_n(H_2O)_m$] where M=$UO_2$(VI), ZrO(IV), Th(IV); L=3-benzylidine-imino-5-p-sulphonamido phenyl azo-2-thiohyatoin(bispt), 3-furfurylidine-imino-5-p-sulphonamido phenyl azo-2-thiohydantoin(fispt),3-pyridyl-2'-methylene-imino-5-p-sulphonamido phenyl azo-2-thiohydantoin(pmispt) and 3-thienyl-2'-methylene-imino-5-p-sulphoanamido phenyl azo-2-thiohydantoin(tmispt); n=8 for Th(IV) and 4 for others, m=4 for bispt and 3 for others have been synthesized and characterized on the basis of elemental analysis, thermal analysis, molar conductance, magnetic moment and spectroscopic data (IR, electronic and $^1H$-NMR). In the light of this information, the ligands can be visualized as tetradentate co-ordinating through azomethine nitrogen, carbonyl oxygen to one metal centre where as azo nitrogen and thioimido nitrogen to the other metal centre yielding homo binuclear complexes of the above composition. The fungi toxicity of the ligands & their zirconyl complexes against some fungal pathogen has been studied.