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Study of BrinkmanBard nanofluid convection with idealistic and realistic boundary conditions and by considering the effects of shape of nanoparticles
This study deals with linear and weakly non-linear stability analyses of BrinkmanBard convection in nanoliquid-saturated porous enclosures. Water with a dilute concentration of molybdenum disulfide nanoparticles with 0.06 volume fraction and 30% glass fiber-reinforced polycarbonate as a porous medium with porosity 0.88 are considered to be a working medium. The analytical solution is obtained in the present study for idealistic and realistic boundary conditions, and their results are compared. An analytically intractable Lorenz model with quadratic nonlinearities is reduced to a tractable GinzburgLandau amplitude equation with cubic nonlinearity using the multiscale method. Nanoparticles with different shapesare considered in the study, and their effects on the onset and heat transfer are discussed in great detail graphically in the presence of other parameters arising in the problem. 2021 Wiley Periodicals LLC -
STUDY OF BOUND AND CONTINUUM STATE BETA DECAY RATES OF A FEW BARE NUCLEI
Beta decay is one of the most widely studied research problems in nuclear physics. There has been a growing interest in understanding the dynamics of beta decay transitions for many decades. Many research groups have invested a lot of time, money and effort in experiments as well as developing the theory for the same. Lot of work was done using Fermis theory and huge amount of data is available in that domain of nuclear physics. But recently, standard model has gained a lot of attention in the eyes of theoretical nuclear physicists and particle physicists to understand nuclear transitions with more importance to gluons mixing and quark mixing by incorporating CKM matrix and PMNS matrix elements. Subsequently, the standard model theory is applied to beta decay to gain a better insight with the application of standard weak interaction Hamiltonian to compute decay rates. The half life and stability of these nuclei depends on decay rates. Also, it gives us an idea about the kind of transitions which happen and which dont. Recent interest in comparison of two modes of beta decay namely, continuum and bound state for same mother and daughter set, paved way for a lot of interesting calculations by various research groups. It is exciting to understand as to how their differences are compared. The aim of this work is to predict continuum and bound state beta decay rates using approach incorporating standard weak theory for some new transitions, which has not been done so far and also compare few decay rates with existing experimental values done by various groups all over the globe. -
Study of Bard-Marangoni Convection in a Microfluid with Coriolis Force
The convection of micro-structured fluid particles and the Coriolis force has been investigated in the problem. The eigenvalues are calculated for upper free velocity and adiabatic temperature boundary conditions and lower rigid velocity and isothermal temperature boundary conditions. The analysis is based on solving linear disturbance equations. The impact of different micropolar fluid variables and the Taylor number based on the convection has also been investigated. The study could observe that while the coupling and micropolar heat conduction parameters along with rotational parameters have a stabilizing effect, the couple stress parameter results in a destabilizing effect. The Author(s), under exclusive license to Springer Nature Switzerland AG 2024. -
Study of 1s internal bremsstrahlung spectrum from 57Co
The internal bremsstrahlung contribution from the electron capture of 57Co has been measured in coincidence with K-X-ray of the residual atom. The end-point energy (EPE) is extracted from the data using the linearised Jauch plot. The transition energy obtained using the (EPE) is 842.7keV, which is close to the value given by Audi and Wapstra. The measured intensity and shape factor from 300 to 600keV are found to be in good agreement with the Glauber and Martin theory. 2002 Elsevier Science Ltd. All rights reserved. -
Studies on Uniaxial Compressive Strength of Laterite Masonry Prisms
Vol-04, No.02, April ISNN: 0974-5904 -
Studies on thermal, structural, electrical and optical properties of Se-Te-Sb chalcogenide glasses /
Glasses, an intriguing state of matter, known to mankind since ages, have seen systematically reported investigations only in the 20th century. Of the various kinds of glasses such as silicates, oxides, halides, chalcogenide etc., a large spectrum of commercial and technological applications of chalcogenide glasses(ChG), have made them a subject of great interest and studied for more than four decades now. -
Studies on the Fresh Water Algal Floria in Chimmony Wildlife Sanctuary
Algae is a crucial organism in the environment. They help in maintaining the balance among different ecosystems. According to the geography and climatic conditions, newlineKerala has a suitable environment for algal growth. However, the algal biodiversity newlinestudies conducted in Kerala are significantly less. The wildlife sanctuary comprises a newlineconsiderable scope for algal biodiversity. The Chimmony wildlife sanctuary is situated in Mukundapuram taluk of Thrissur district. It spreads over 85.067 km2 with a water spread area of 10.1 km2. Ten different sampling stations were selected across newlinethe wildlife sanctuary, and extensive field visits were conducted to identify and newlinedocument the algae with respect to three seasons (pre-monsoon, monsoon, and post- newlinemonsoon). The physicochemical parameters of water like dissolved oxygen, temperature, pH, alkalinity, total dissolved solids, light intensity, and rainfall amount were estimated seasonally. In this present study, a total of 121 taxa belonging to 60 genera, 38 families, 24 orders, and 5 classes, namely Chlorophyceae, Bacillariophyceae, Euglenineae, Rhodophyceae, and Cyanophyceae, were identified from 10 different stations. The Bacillariophyceae and Chlorophyceae were the most dominant class in the study area. The algal multiplication will be more in the pre monsoon season and it was observed that the Chlorophyceaen members were dominant, while the Bacillariophyceae were dominant during the post-monsoon season. Cyanophyceae was dominant only during the monsoon season because of its sensitivity toward light. The ANOVA (Two-way) analysis showed no significant difference between stations, and there is a considerable difference between seasons for dissolved oxygen, alkalinity, temperature, and total dissolved solids. While pH, showed no significant difference between seasons and stations, light intensity showed a substantial difference between stations and seasons. The temperature and dissolved oxygen showed a negative correlation. -
Studies on the Culture Conditions, Nutritional Value of the Black Soldier Fly, Hermetia illucens (Diptera : Stratiomyid) and its Suitability as Aquaculture Feed
The Black Soldier Fly (BSF), Hermetia illucens, has emerged as a promising newlinesolution in aquaculture due to its remarkable ability to convert organic waste into newlineprotein-rich biomass. This has garnered interest among aquaculturists seeking costeffective and sustainable alternative ingredients for aqua feed. However, fully newlineharnessing the potential of this insect requires a deeper understanding of its life cycle and nutritional composition. A key challenge in utilising BSF larvae (BSFL) for newlineaquafeed production is the lack of standardized culture systems. This study addresses this gap by establishing a comprehensive culture system using two common organic wastes, fruit waste (FW) and vegetable waste (VW), as rearing substrates. By evaluating the growth performance of BSFL reared on these substrates, the research sheds light on optimal conditions for large-scale BSF production. The study investigated the impact of FW and VW substrates on BSFL growth through a thorough analysis of growth performance, morphometric measurements and newlineScanning Electron Microscopy (SEM). Results showed that BSFL reared on FW exhibited better growth (40 days) than those reared on VW (46 days). Morphometric analysis and SEM identified five larval stages and the prepupa, pupa, and adult stages. Additionally, the study analysed the nutritional composition of BSFL at different newlinedevelopmental stages, such as Instar 3 through instar 5, prepupa and pupa, including newlineprotein, carbohydrate, lipid, amino acids and fatty acids. This provided insights into newlinehow variations in substrate impact the nutritional quality of BSFL at different stages, which is crucial for ensuring that BSFL-derived feed meets the dietary requirements of target aquaculture species. Significant differences were found in the proximate composition of the substrates (FW and VW), resulting in significant variations in BSFL nutrition. BSFL reared on FW exhibited higher nutritional content especially crude newlineprotein (54.160.64%), than those reared on VW, except for crude lipids (2.200.01%). -
Studies on the characterisation of thiophene substituted 1,3,4-oxadiazole derivative for the highly selective and sensitive detection of picric acid
A novel thiophene substituted 1,3,4-oxadiazole based chemosensor namely 2-(4-(5-(5-hexylthiophen-2-yl) thiophen-2-yl)phenyl) -5-(5-(5-(5-hexylthiophen-2-yl) thiophen-2-yl)thiophen-2-yl)-1,3,4-oxadiazole [TKO] has been characterised for the efficient detection of picric acid (PA) based on fluorescence quenching mechanism. In this regard, the electronic absorption spectra, fluorescence spectra, and fluorescence lifetime of TKO are recorded in the presence of different nitroaromatic compounds (NACs) in ethanol at room temperature. The absorption studies exhibited a blue shift in the absorption maxima with the increase in the concentration of PA. In the fluorescence titration studies, TKO shows a remarkable fluorescence quenching with picric acid as compared to other nitroaromatic compounds. Using the Benesi-Hildebrand plot, the binding constant value of PA with TKO is determined and is of the order of 6.467 104 M?1. Job's plot analysis confirms the 1:1 binding stoichiometry ratio between TKO and PA and is supported by the 1H NMR studies. The detection limit is determined and is of the order of 10.08 M. The competitive studies revealed that TKO is highly selective for recognizing PA without the interference of other NACs. The theoretical studies were also carried out to understand the binding mechanisms of PA with TKO. The fluorescence quenching of TKO by PA may be attributed to photo induced electron transfer (PET). Overall, the experimental findings suggest that, the novel probe TKO may be used as a highly selective and sensitive chemosensor for the detection of explosives like picric acid. 2022 Elsevier B.V. -
Studies on the antifungal activity of biotemplated gold nanoparticles over Candida albicans
Green synthesis and applications of gold nanoparticles are more fascinating research area due to their unique optical properties and high X-ray attenuation power. In this study, we have synthesized gold nanoparticles of uniform size (5 nm) with spherical shape. UVvis spectroscopy, Transmission Electron Microscopy and Atomic Force Microscopy were employed to characterize the synthesized gold nanoparticles. The biomedical applications of the synthesized gold nanoparticles were carried out against most prevalent human fungal pathogen, Candida albicans. Broth micro dilution assay was used to determine minimum inhibitory concentration (MIC). We observed that 0. 5 mM concentration was effective in inhibiting the growth of fungal cells which was later confirmed by spot assay. 2019 Elsevier Ltd -
Studies on Tensile Properties of Graphene Hydroxyl Reinforced Aluminium 6061 Composites for Vehicle Structures Applications
Aluminium composite plays a significant role in the mechanical structures. Low tensile strength of the aluminium alloy limits its application in mechanical structures. Graphene hydroxyl (GrOH) is a noble emerging material which is an allotropic form of carbon. It has high cohesive strength, good bonding ability with other materials. Carbon bonds processes high compatibility when it reinforced with other material. Reinforcement of GrOH with aluminium composites enhances the wear strength of composite material. This paper focused on analysis of tensile properties and percentage elongation of aluminium composites reinforced with GrOH with various weight percentage (wt. %). The characteristics of aluminium composites, particularly related to its tensile properties are very much important for its use in vehicle structures applications. 2022. MechAero Foundation for Technical Research & Education Excellence. -
Studies on sulfur doping and figure of merit in vapor grown Sb2Te3 platelet crystals /
Journal Of Crystal Growth, Vol.412, pp.65-71, ISSN No: 0022-0248. -
Studies on sulfur doping and figure of merit in vapor grown Sb2Te3 platelet crystals
A series of p-type Sb2Te3-xSx(x=0, 0.1, 0.2, 0.3 and 0.4) samples for each sulfur composition was vapor deposited to explore the crystal growth mechanism of platelet morphology and to understand their potential use for thermoelectric devices. Structural characterization performed by X-ray diffraction exhibited consistent rhombohedral unit cell parameters for all the antimony telluride crystals with D3d5 space group symmetry. Scanning electron microscopy (SEM) and energy dispersive analysis by X-rays (EDAX) were employed for morphological and compositional studies. The Seebeck coefficient S (?c) of Sb2Te3-xSx crystals for sulfur composition, x=0.3 was remarkably improved, yielding a figure of merit (ZT)=0.54, which is ?2.5 fold rise compared to the melt grown Sb2Te3 crystals. The atomic force microscopic (AFM) imprints revealed that, with increasing content of dopant, distribution of etch pits and microhardness increased in sulfur doped crystals. By optimizing sulfur doping, the antisite (AS) defect formation can be suppressed for enhancing ZT and the results obtained enable to design novel thermoelectric materials for application in power generation and refrigeration. 2015 Elsevier B.V. All rights reserved. -
Studies on single crystals and thin films on tin sulfide (SnS) for photovoltaic applications
There is an increasing demand for renewable energy sources due to the limited availability of fossil, risk factor associated with nuclear fuel and due to growing environmental concern. Photovoltaic (PV) energy conversion has the potential to contribute significantly to the electrical energy of the main obstacles preventing production and application on a large scale. Availability of the materials and their processing cost are the two major constraints associated with the presently leading PV technologies. Hence, cost of the electricity produced by these technologies are not yet competitive compared to the electricity produced by conventional sources. -
Studies On Single Crystals and Thin Films of Tin Sulfide(SnS) For Photovoltaic Applications
The thesis is concerned with linear and nonlinear Rayleigh-Bard electroconvection in a horizontal porous layer. Modified Darcy law is employed to describe the fluid motion. The effect of non-classical heat conduction, chemical reaction, thermal radiation and finite amplitudes on the onset of Darcy electroconvection is considered. The findings of the problems investigated in the thesis may prove useful in heat transfer application situations with dielectric fluids as working medium. The summary of the problems addressed in the thesis is given below.Effect of non-classical heat conduction on Rayleigh-Bard newlineconvection in a horizontal layer of porous medium saturated with a dielectric fluid The method of small perturbations is used to examine the effect of non-classical heat conduction on the onset of Darcy electroconvection. Exact solutions for both stationary and oscillatory instability are obtained and known results have been deduced as limiting cases of the present study. It is shown that electroconvective instability in a Darcy porous layer is hastened by increasing the strengths of second sound and electric newlineforces and that the presence of second sound and dielectrophoretic force leads to shorter wavelength electroconvection. Further, it is found that the effect of Vadasz number is to advance the onset of oscillatory Darcy newlineelectroconvection and oscillatory instability sets in before stationary convection provided that the Vadasz number and the Cattaneo number are sufficiently large. Rayleigh-Bard convection in a horizontal layer of porous medium saturated with a chemically reacting dielectric fluid The problem of the effect of chemical reaction on the onset of Darcy electroconvection in a horizontal porous layer heated from below is newlineinvestigated. It is assumed that the fluid experiences a zero-order exothermic chemical reaction and that there exists a local thermal equilibrium between the fluid and the solid phases. -
Studies on photophysical properties of mono-carbonyl curcumin analogues: Experimental andtheoretical approach
The solvatochromic fluorescence behaviour of mono-carbonyl curcumin analogues has been studied in ten different solvents ranging from non-polar to polar. The solvent effect on the spectral properties of analogues has been discussed. The ground state dipole moments were estimated experimentally by Bilot-Kawski equation which is a function of Stokes shift with the solvent polarity parameters and Guggenheim method and theoretically by TD-DFT studies. The excited state dipole moment was determined using Bilot-Kawski equations. The excited state dipole moments for the two molecules were found to be higher than their corresponding ground state dipole moments. Theoretically Frontier molecular orbital (HOMO/ LUMO) energies were determined by Gaussian 09 W software using TD-DFT. 2018 Oriental Scientific Publishing Company. All rights reserved. -
Studies on Photophysical and Biological Activity of Newly Synthesized of 4-Methylpiperidin-4-ol Substituted Pyrazole Derivatives
The in vitro antifungal, antibacterial, and antioxidant activities of a substituted pyrazole derivative (FHM) have been evaluated in the current work. The addition of 4-methylpiperidin-4-ol, which increases the molecules lipid solubility and speeds up absorption by increasing its rate of absorption, gives the molecule strong in vitro antifungal and antibacterial properties. Additionally, it is clear from the findings of structure-activity relationship (SAR) investigations. Additionally, the ab-intio technique was used to theoretically evaluate the photophysical characteristics of produced substances. Using the DFT-B3LYP-6-31G(d) basis set, the ground state optimization and HOMO-LUMO energy levels are computed. Global chemical reactivity and descriptive characteristics are evaluated using theoretically estimated HOMO-LUMO values, and the results demonstrate that the synthesized molecule possesses a high electrophilicity and electronegative index. Overall findings indicate that substituting a 4-methylpiperidin-4-ol substituted pyrazole derivative shows good photophysical and in vitro biological applications. 2024, HARD Publishing Company. All rights reserved. -
Studies on phase transitions and dielectric properties of biowaste synthesized porous carbon nanoparticlesferroelectric liquid crystal mixture
Ferroelectric liquid crystals(FLCs), an exciting class of liquid crystals(LCs), found potential applications in the display as well as non-display regimes due to their fast response, low driving voltage and nonvolatile memory. The amalgamation of nanoparticles into FLCs has opened up new avenues in the LCs research field by alterations/modification of the existing properties of LCs. In this work, porous carbon nanoparticles (PCNPs) were dispersed into FLC mixture (W206E) and investigated their doping effect on FLCs textural, phase transition temperatures and dielectric studies in planar-aligned cells. Dielectric spectroscopy was carried out in the frequency range of 20 Hz to 10 MHz to explore the frequency as well as the temperature dependent of FLC in the entire SmC* region. The transition temperature of FLC mixture is increased by 4 C in PCNPs doped FLC sample then undoped FLC sample. Nearly 8.42% increase in permittivity is observed. A Gold stone relaxation mode at ?627 Hz was observed at lower frequency. 2024 Taylor & Francis Group, LLC. -
Studies on Parametric Optimization of HVOF-Sprayed Cr2O3 Coatings on Al6061 Alloy
High-velocity oxy-fuel (HVOF) is a widely used thermal spray technique to obtain high density, high bond strength, and improved hardness coatings. In the present work, optimization of HVOF process parameters was carried out using the Taguchi method to minimize porosity and improve microhardness, and bond strength of Cr2O3 coatings. Based on the signal-to-noise ratio and analysis of variance, the significance of each process parameter and optimum parameter combination is obtained. Based on the signal-to-noise ratio, the most significant process parameter affecting porosity and microhardness was standoff distance, while for bond strength, it was powder feed rate. An optimal combination of process parameters for porosity, microhardness, and bond strength was obtained from S/N ratio analysis. For porosity, optimal parameters were standoff distance of 100rpm, powder feed rate of 30g/min, and gun speed of 250mm/s. The optimal process parameters for microhardness were standoff distance of 300rpm, powder feed rate of 50g/min, and gun speed of 200mm/s. Finally, for bond strength, the optimal process parameters were standoff distance of 300rpm, powder feed rate of 50g/min, and gun speed of 250mm/s. Statistical results for porosity, microhardness, and bond strength showed that the difference between the predicted R2 and adjusted R2 values were relatively minimal and close to the one highlighting the fitness of the regression model employed for analysis. Fracture analysis after bond strength test showed combined adhesion/cohesion type failure for the Cr2O3 coatings. 2021, The Indian Institute of Metals - IIM.