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Koushik Ghosh

Bio: Koushik Ghosh is an academic researcher from Jadavpur University. The author has contributed to research in topics: Heat transfer & Subcooling. The author has an hindex of 13, co-authored 64 publications receiving 550 citations.


Papers
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Journal ArticleDOI
TL;DR: A Schiff-base compound, 1-(2-hydroxy-5-methylphenylimino)naphthalen-2-ol (1b), has been synthesized and characterized using elemental analysis and different spectroscopic methods as discussed by the authors.
Abstract: A Schiff-base compound, 1-(2-hydroxy-5-methylphenylimino)naphthalen-2-ol (1b), has been synthesized and characterized using elemental analysis and different spectroscopic methods. It behaves as highly selective fluorescent chemosensor for Al(III) in 10 mM HEPES buffer in water:methanol (1:9, v/v) (pH 7.2). Fluorescence intensity at 552 nm (excitation at 450 nm) of 1b increases about 200 fold upon addition of 2 equiv. of Al3+ ion. Quantum yield of 1b increases about 10.8 times upon complex formation with Al3+. 1b forms complex with Al3+ in 1:1 ratio as supported by Job's plot analysis and mass spectroscopic measurement. Chelation enhanced fluorescence of 1b in the presence of aluminum(III) ion is evidenced from large decrease in nonradiative rate constant and high binding constant value. The probe molecule has been applied in living cell imaging study.

65 citations

Journal ArticleDOI
TL;DR: In this article, heat transfer and entropy generation characteristics are numerically investigated in the presence of single and double obstructive blocks within a square enclosure, and it is found that the adiabatic block(s) enhance the heat transfer marginally up to a critical size in a convection-dominated regime.
Abstract: In the present work, heat transfer and entropy generation characteristics are numerically investigated in presence of single and double obstructive blocks within a square enclosure. It is found that the adiabatic block(s) enhance(s) the heat transfer marginally up to a critical size in a convection-dominated regime. On the other hand, the enhancement parameter is observed to be more with an increase in block size in a lower range of Rayleigh numbers for an isothermal block. The entropy generation for thermal irreversibility is observed to be several orders higher than that due to viscous dissipation in all cases.

62 citations

Journal ArticleDOI
TL;DR: In this paper, the thermal aspects of a differentially heated porous square enclosure in the presence of an adiabatic block of different block sizes utilizing Darcy-Rayleigh number in the range of 1-10,000 with Darcy number was investigated.
Abstract: The present work investigates the thermal aspects of a differentially heated porous square enclosure in the presence of an adiabatic block of different block sizes utilizing Darcy–Rayleigh number in the range of 1–10,000 with Darcy number $$10^{-2}$$ – $$10^{-6}$$ . Heatlines and Nusselt number, streamlines, and entropy generation are used for the analysis of heat transfer, flow circulation, and irreversibility production in the enclosure. The study reveals that the presence of an adiabatic block affects the heat transfer process severely, and three different zones of heat transfer are identified. These are namely the zone of heat transfer augmentation, the zone of heat transfer augmentation along with entropy generation reduction, and the zone of both heat transfer and entropy generation reduction. It is also found that the presence of an adiabatic block can enhance heat transfer up to a certain critical block size; thereafter, further increasing in block size reduces the heat transfer rate. An optimal block size where the heat transfer enhancement is maximum is observed to be smaller than the critical block size. The study demonstrates the analyses of heat transfer and entropy generation for a better thermal design of a system. This study is also extended for higher Prandtl number fluids.

47 citations

Journal ArticleDOI
TL;DR: In this article, three new copper(II) complexes with different Schiff-base ligands, namely, [Cu(L1)Cl2] (1), [Cu3(L2)2Cl4] (2) and [cu(L3)N3]n (3), have been synthesized and characterized by elemental analysis, standard spectroscopic methods, cyclic voltammometry and single crystal X-ray diffraction analysis.
Abstract: Three new copper(II) complexes with different Schiff-base ligands, namely, [Cu(L1)Cl2] (1), [Cu3(L2)2Cl4] (2) and [Cu(L3)N3]n (3) where L1 = 2-morpholino-N-(pyridin-2-ylmethylene)ethanamine, HL2 = 4-bromo-2-((2-morpholinoethylimino)methyl)phenol and HL3 = 4-chloro-2-((2-(dimethylamino)ethylimino)methyl)phenol, have been synthesized and characterized by elemental analysis, standard spectroscopic methods, cyclic voltammometry and single crystal X-ray diffraction analysis The X-ray diffraction analysis confirms the formation of mononuclear (1), trinuclear (2) and polynuclear (3) complexes These complexes have been applied as catalysts for alcohol oxidation reactions using tert-butyl hydroperoxide (TBHP) as the terminal oxidant under mild conditions The catalytic reaction mixture has been analyzed by gas chromatography and it shows that the mononuclear complex has the highest conversion while the other two complexes exhibit moderate catalytic activities The corresponding aldehyde has been obtained as the sole product The obtained catalysis results have been corroborated with electrochemical studies

28 citations


Cited by
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[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

01 Jan 2016
TL;DR: The numerical heat transfer and fluid flow is universally compatible with any devices to read and is available in the authors' digital library an online access to it is set as public so you can get it instantly.
Abstract: Thank you for reading numerical heat transfer and fluid flow. Maybe you have knowledge that, people have search numerous times for their favorite books like this numerical heat transfer and fluid flow, but end up in infectious downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they cope with some malicious virus inside their computer. numerical heat transfer and fluid flow is available in our digital library an online access to it is set as public so you can get it instantly. Our books collection spans in multiple countries, allowing you to get the most less latency time to download any of our books like this one. Merely said, the numerical heat transfer and fluid flow is universally compatible with any devices to read.

1,531 citations

Journal ArticleDOI
TL;DR: This Review discusses the efforts undertaken so far to achieve efficient charge transport in MOFs and focuses on four common strategies that have been harnessed toward high conductivities.
Abstract: Metal–organic frameworks (MOFs) are intrinsically porous extended solids formed by coordination bonding between organic ligands and metal ions or clusters. High electrical conductivity is rare in M...

751 citations

01 Aug 1953
TL;DR: In this paper, a solution for the radius of the vapor bubble as a function of time is obtained which is valid for sufficiently large radius, since the radius at which it becomes valid is near the lower limit of experimental observation.
Abstract: The growth of a vapor bubble in a superheated liquid is controlled by three factors: the inertia of the liquid, the surface tension, and the vapor pressure. As the bubble grows, evaporation takes place at the bubble boundary, and the temperature and vapor pressure in the bubble are thereby decreased. The heat inflow requirement of evaporation, however, depends on the rate of bubble growth, so that the dynamic problem is linked with a heat diffusion problem. Since the heat diffusion problem has been solved, a quantitative formulation of the dynamic problem can be given. A solution for the radius of the vapor bubble as a function of time is obtained which is valid for sufficiently large radius. This asymptotic solution covers the range of physical interest since the radius at which it becomes valid is near the lower limit of experimental observation. It shows the strong effect of heat diffusion on the rate of bubble growth. Comparison of the predicted radius‐time behavior is made with experimental observations in superheated water, and very good agreement is found.

729 citations

Book ChapterDOI
28 Jan 2005
TL;DR: The Q12-40 density: ρ ((kg/m) specific heat: Cp (J/kg ·K) dynamic viscosity: ν ≡ μ/ρ (m/s) thermal conductivity: k, (W/m ·K), thermal diffusivity: α, ≡ k/(ρ · Cp) (m /s) Prandtl number: Pr, ≡ ν/α (−−) volumetric compressibility: β, (1/K).
Abstract: Geometry: shape, size, aspect ratio and orientation Flow Type: forced, natural, laminar, turbulent, internal, external Boundary: isothermal (Tw = constant) or isoflux (q̇w = constant) Fluid Type: viscous oil, water, gases or liquid metals Properties: all properties determined at film temperature Tf = (Tw + T∞)/2 Note: ρ and ν ∝ 1/Patm ⇒ see Q12-40 density: ρ ((kg/m) specific heat: Cp (J/kg ·K) dynamic viscosity: μ, (N · s/m) kinematic viscosity: ν ≡ μ/ρ (m/s) thermal conductivity: k, (W/m ·K) thermal diffusivity: α, ≡ k/(ρ · Cp) (m/s) Prandtl number: Pr, ≡ ν/α (−−) volumetric compressibility: β, (1/K)

636 citations