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178 results on '"Das, Nirmalya"'

57. A study to assess the quality of life (QOL) of patients suffering from tinea corporis attending dermatology OPD of a tertiary care centre of Eastern India

Author

Kumar Das, Nirmalya, Das, Suchibrata, Kumar Das, Nirmalya, and Das, Suchibrata

Abstract

Background: A huge number of patients in our country are affected by Tinea Corporis (TC). The number of patients affected by dermatophytosis has increased by a large extent in the last 4 to 5 years. The quality of life in TC patients can be affected by various factors including the disease morbidity, duration of disease, social & demographic factors. Aims and Objectives: The aim of the study is to find out the effect of TC on the quality of life of the affected patients & along with that to assess whether there is some association of this effect on quality of life with some demographic & clinical factors. Methods: The effect on quality of life of 328 patients affected by TC who attended the Dermatology outpatient’s department of NRS Medical College was assessed using the Dermatology Life Quality Index (DLQI) questionnaire. Results: 12 (3.658 %) of the patients had an extremely large effect on quality of life. There was a very large effect on the QOL of 121 (36.890 %) patients. There was moderate effect on 134 (40.853 %) of the patients. There was a small effect on 59 (17.987 %) of the patients. 2 (0.609 %) patients had no effect on their QOL. Duration of disease & body surface area involved have significant impacts on QOL. Conclusion: The quality of life is adversely affected by TC. Early detection & treatment of the disease is very important. Steps must be taken to increase awareness about the disease among the general population.

Published
2019

59. BaSnO3 Nanoparticles as Blue Emitting Phosphor and Efficient Photocatalyst.

Author

Pal, Suvra, Das, Nirmalya Sankar, Das, Brahami, Das, Biswajit, Mukhopadhyay, Subhadipta, and Chattopadhyay, Kalyan Kumar

Subjects
*LUMINESCENCE, *ELECTRON field emission, *WATER disinfection, *METHYLENE blue, *PHOSPHORS, *ELECTRON transport
Abstract

BaSnO3 has been studied for photovoltaic application for many decades in addition to its popular dielectric studies. However, a complete investigation of its remarkable optical properties may groom this novel perovskite as multipurpose system covering wide variety of optical and electrical applications. In this regard, few studies have been dedicated to investigate its photoluminescence properties. In this work nanocubes of BaSnO3 were prepared in simple solid-state reaction. X-ray diffraction studies, field emission scanning electron microscopic studies and energy dispersive X-ray studies confirmed its structural purity, cube like morphology and proper composition respectively. The optical band gap of this system was studied in detail to determine its band gap which was found to be in UV range. The samples were then excited with UV photons to study its luminescence response. The persistent nature of its luminescence response was confirmed from time resolved photoluminescence (TRPL) study which showed that the as synthesized samples were able to emit persistent blue radiation for duration ~ 1.4 microseconds indicating its future application in emerging LED sector. Using the UV excitation phenomenon, the sample was subjected to undergo water disinfection test to remove methylene blue. A moderate degradation performance with degradation rate constant ~0.02 min-1 was observed for the sample which uncovers potential multifunctional nature of this novel perovskite. [ABSTRACT FROM AUTHOR]

Published
2020
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60. Facile Preparation of Porous Ga2O3 Nano/microbars for Highly Efficient Photocatalytic Degradation.

Author

Das, Brahami, Das, Biswajit, Pal, Suvra, Sarkar, Ratna, Das, Nirmalya Sankar, Sarkar, Subrata, and Chattopadhyay, Kalyan Kumar

Subjects
WATER pollution, ORGANIC water pollutants, METHYLENE blue, POLLUTANTS, EMPLOYEE reviews, PERFORMANCE standards
Abstract

As a facile solution of emerging health issues caused by organic and inorganic pollutants in consumable water, low dimensional novel materials are employed for catalytic removal of hazardous contaminants. Gallia has been a wellknown candidate in this field. This work demonstrates effective separation of wide range of popular water contaminants of different ionic and chemical identity. Aiming to this, porous bar like α- Gallia nanostructures were synthesized using facile solid state route. Thorough characterization of the samples were performed via XRD, FESEM, EDX and UV-Vis spectrophotometry to investigate its structural, morphological, compositional and optical band gap related features. The samples were found to exhibit wide UV range band gap. After identification of its excitation energy, the sample was subjected to standard photocatalytic performance to degrade hazardous water pollutants like Methylene Blue (MB) and Eosin B (EB). To closely mimic real water contaminants, proportional mixture of the dyes were also degraded using the sample. It was observed that the sample exhibit remarkable degradation efficiency with rate constant as high as 0.47516 min-1 and it also proved to retain degradation efficiency even after multiple cycles. [ABSTRACT FROM AUTHOR]

Published
2020
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62. Tailored CsPbX3 Nanorods for Electron-Emission Nanodevices

Author

Paul, Tufan, primary, Maiti, Soumen, additional, Besra, Nripen, additional, Chatterjee, Biplab Kr, additional, Das, Bikram Kumar, additional, Thakur, Subhasish, additional, Sarkar, Saikat, additional, Das, Nirmalya Sankar, additional, and Chattopadhyay, Kalyan Kumar, additional

Published
2019
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84. White light emitting MgAl2O4:Dy3+,Eu3+ nanophosphor for multifunctional applications.

Author

Panigrahi, Karamjyoti, Saha, Subhajit, Sain, Sumanta, Chatterjee, Rituparna, Das, Antika, Ghorai, Uttam Kumar, Sankar Das, Nirmalya, and Chattopadhyay, Kalyan Kumar

Subjects
RARE earth ions, LED lighting
Abstract

Feeble white emission with a low Colour Rendering Index (CRI) has become the principal gridlock for the extensive commercialization of phosphor converted white LEDs (pc-WLEDs). Fusion of red, green and blue emitting rare-earth (RE) ions in a suitable host can overcome these drawbacks but the energy migration between multiple RE ions at single excitation wavelength defines the key standpoint in designing such white light emitting phosphors. Apart from the abovementioned obstacles, recently traditional optical temperature sensors based on RE ions have faced difficulties due to their low relative sensitivity and large detection error. Keeping these points in mind, in this work, a series of MgAl2O4:Dy3+,Eu3+ nanophosphors are synthesized among which 2% Dy3+,0.2% Eu3+ doped MgAl2O4 nanophosphors demonstrate strong white emission with CIE co-ordinates of (0.31, 0.33), and high quantum yield (∼67%), which could be directly utilized for pc-WLED based solid state lighting devices. Detailed investigation of PL properties reveals that Eu3+ ions can be well sensitized by Dy3+ under near-ultraviolet excitation of 351 nm. Dexter's theory & Reisfeld's approximation are employed for an in-depth analysis of the inter-RE energy transfer (ET) mechanism, which signposts that the dipole–quadrupole interaction phenomenon is responsible for the ET process from Dy3+ to Eu3+. Additionally, the validated ET plays a pivotal role in demonstrating the self-referencing ratiometric temperature sensor behaviour supported by a distinct high temperature thermal quenching trend between Dy3+ and Eu3+ ions. Hence the obtained nanophosphors are highly promising for utilizing in WLED based solid state lighting and self-referencing ratiometric temperature sensor applications. [ABSTRACT FROM AUTHOR]

Published
2018
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85. Flower-like Cu2NiSnS4 microspheres for application as electrodes of asymmetric supercapacitors endowed with high energy density.

Author

Sarkar, Samrat, Howli, Promita, Ghorai, Uttam Kumar, Das, Biswajit, Samanta, Madhupriya, Das, Nirmalya Sankar, and Chattopadhyay, Kalyan Kumar

Subjects
COPPER compounds, SUPERCAPACITORS, ENERGY density
Abstract

Design of electrode materials for supercapacitors using earth-abundant and less-toxic metals is both cost effective and environmentally benign. The present study deals with the synthesis of flower-like Cu2NiSnS4 microspheres (FCMs) and utilizing the same as positive electrodes of solid-state asymmetric supercapacitors. Citric acid was used for the synthesis of Cu2NiSnS4 as the structure directing agent; a possible growth mechanism of the formation of flower-like microspheres is proposed. The as-prepared FCMs on nickel foam demonstrated a high specific capacitance of 1639 F g−1 at a scan rate of 5 mV s−1. The as-fabricated solid-state asymmetric device achieved high values of volumetric (8.81 F cm−3) and gravimetric (105.7 F g−1) capacitances. The device attained the maximum energy density of 2.57 mW h cm−3/30.88 W h kg−1 and high power density of 201.4 mW cm−3/2.42 kW kg−1. Superior capacitance retention of the device was confirmed as it maintained 95.7% of the initial capacitance after 2000 cycles. Thus, by effective integration on a large-scale basis, these supercapacitors have great potential for the development of sustainable energy storage systems using low-cost earth-abundant materials. [ABSTRACT FROM AUTHOR]

Published
2018
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86. Enhanced photoconductance in ZnS-RGO-based nanocomposite under UV irradiation.

Author

Roy, Rajarshi, Das, Nirmalya Sankar, Sen, Dipayan, Saha, Subhajit, and Chattopadhyay, Kalyan Kumar

Subjects
*ZINC sulfide, *IRRADIATION, *GRAPHENE oxide, *DETECTORS, *NANOCOMPOSITE materials
Abstract

Zinc Sulfide (ZnS) has the potential to act as UV detectors in various optoelectronic device applications. However average photoresponse and slow current decay in ZnS have limited its usage. Hence, an attempt has been made to redeem zinc sulfide's (ZnS) potential as an efficient UV detector through ZnS-RGO nanocomposite formation using a facile technique. It was found that due to the incorporation of reduced graphene oxide (RGO) in tandem with ZnS led to significant improvement in the off-time current decay and photoconductance with light to dark ON-Off ratio increasing up to ~ 1.96 × 10. [ABSTRACT FROM AUTHOR]

Published
2018
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98. Simple Chemical Route Synthesis of Fe 2 O 3 Nanoparticles and its Application for Adsorptive Removal of Congo Red from Aqueous Media: Artificial Neural Network Modeling.

Author

Debnath, Animesh, Deb, Krishna, Das, Nirmalya Sankar, Chattopadhyay, Kalyan Kumar, and Saha, Biswajit

Subjects
IRON oxide nanoparticles, NANOPARTICLE synthesis, CRYSTAL structure, CONGO red (Staining dye), ARTIFICIAL neural networks, FOURIER transform infrared spectroscopy
Abstract

Nanocrystalline Fe2O3powder was synthesized by a simple chemical route involving FeCl3and NaOH. The Fe2O3powder thus prepared was characterized using x-ray diffraction study, scanning electron microscopy, and Fourier transform infrared spectroscopy. The adsorption properties of crystalline Fe2O3powder have been investigated with an aim to explore a possible low cost and efficient way to remove Congo red (CR) from waste water. Fe2O3powder was found as an excellent adsorbent for CR from aqueous medium. Adsorption capacity as much as 203.66 mg g−1is reported at room temperature. Effect of different experimental parameters such as reaction pH, initial CR dye concentration, adsorbent dose, and reaction temperature were studied on adsorption capacity of Fe2O3powder and modeled by artificial neural network (ANN). Optimal ANN structure (4–5–1) shows minimum mean squared error (MSE) of 0.00235 and determination coefficient (R2) of 0.991 with Levenberg–Marquardt algorithm. Isotherm analysis of experimental data exhibited better fit to the Langmuir isotherm. The adsorption process was found to follow second-order kinetics as depicted by the analysis of experimental results. Thermodynamic study shows that the adsorption process is endothermic, spontaneous, and thermodynamically favorable in the temperature range of 27°C to 60°C. [ABSTRACT FROM PUBLISHER]

Published
2016
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