Praveen Pandey

University of Delhi

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Co-Authors

D. Gillotay

Royal Belgian Institute for Space Aeronomy

Koen De Ridder

Flemish Institute for Technological Research

P. K. Bhatnagar

University of Delhi

P. C. Mathur

PES University

Maneesha

University of Delhi

Abhishek Verma

Amity University

Nicole Van Lipzig

KU Leuven

Jitender Kumar

University of Delhi

Swati Nagpal

University of Delhi

Thaize Baroni

National University of Ireland

Cooperative Institutions

University of Delhi

Centre National de la Recherche Scientifique

Université de Versailles Saint-Quentin-en-Yvelines

Laboratoire atmosphères, milieux, observations spatiales

Sorbonne Université

KU Leuven

Institut Pierre-Simon Laplace

Université Paris-Saclay

Royal Belgian Institute for Space Aeronomy

National University of Singapore

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Development of Low Size Dispersion, High Volume Fraction and Strong Quantum Confined CdS<sub>x</sub>Se<sub>1-x</sub> Quantum Dots Embedded in Borosilicate Glass Matrix and Study of their Optical Properties

Advanced materials research (2007)

Abhishek Verma P.K. Bhatnagar P.C. Mathur S. Nagpal Praveen Pandey

Volume fraction

10.4028/0-87849-471-5.161

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Proceedings of PV 2015

Simon N. Waddington Emma Tonkin Charaka Palansuriya Christian Müller Praveen Pandey

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Advanced materials research (2007)

Abhishek Verma P. K. Bhatnagar P. C. Mathur Swati Nagpal Praveen Pandey

Quantum Dots (QDs) of CdSxSe1-x embedded in borosilicate glass matrix (BGM) have been grown using colored glass filter (RG695). Double-Step (DS) annealing method was adopted in which nucleation is achieved at a lower temperature (475°C) without any crystallization. To obtain crystallization on these nucleation centers, the annealing temperature is raised to 575°C at which the nucleation rate is negligible. QDs of various average radii and volume fractions are grown by varying the annealing duration from 3 to 11hrs. QDs corresponding to higher annealing duration are found to have low size dispersion (SD) and high volume fraction but weak quantum confinement, while, the QDs corresponding to lower annealing durations have high quantum confinement due to their much lower radii as compare to Bohr exciton radius, their SD is high and volume fraction low. For nonlinear optical applications the SD must be low and volume fraction should be high. Attempt has been made to optimize the two parameters. Further it has been concluded that there is no contribution of the band edge recombination to the PL and the origin of the PL is due to shallow traps existing in the volume of the QDs. Studies of absorption and PL have also been made on the samples aged for 18, 24 and 36 months. It is found that the effect of aging is to increase the absorption coefficient, reduce the shallow trap centers and reduce the SD.

Volume fraction

Bohr radius

10.4028/www.scientific.net/amr.31.161

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The effect of satellite retrieved cloud optical thickness on surface UV irradiance and photolysis rate coefficients

AGU Fall Meeting Abstracts (2011)

Praveen Pandey Koen De Ridder D. Gillotay

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Assimilating remotely sensed cloud optical thickness into a mesoscale model

Dirk Lauwaet Koen De Ridder Praveen Pandey

Abstract. The Advanced Regional Prediction System, a mesoscale atmospheric model, is applied to simulate the month of June 2006 with a focus on the near surface air temperatures around Paris. To improve the simulated temperatures which show errors up to 10 K during a day on which a cold front passed Paris, a data assimilation procedure to calculate 3-D analysis fields of specific cloud liquid and ice water content is presented. The method is based on the assimilation of observed cloud optical thickness fields into the Advanced Regional Prediction System model and operates on 1-D vertical columns, assuming that there is no horizontal background error covariance. The rationale behind it is to find vertical profiles of cloud liquid and ice water content that yield the observed cloud optical thickness values and are consistent with the simulated profile. Afterwards, a latent heat adjustment is applied to the temperature in the vertical column. Data from 4 meteorological surface stations around Paris are used to verify the model simulations. The results show that the presented assimilation procedure is able to improve the simulated 2 m air temperatures and incoming shortwave radiation significantly during cloudy days. The scheme is able to alter the position of the cloud fields significantly and brings the simulated cloud pattern closer to the observations. As the scheme is rather simple and computationally fast, it is a promising new technique to improve the surface fields of retrospective model simulations for variables that are affected by the position of the clouds.

Shortwave radiation

Shortwave

Liquid water content

Atmospheric models

Cloud height

Cloud physics

10.5194/acpd-11-13355-2011

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The Measurement of the Solar Spectral Irradiance Variability during the Solar Cycle 24 using SOLAR/SOLSPEC on ISS

European geosciences union general assembly (2016)

David Bolsée Nuno Pereira Praveen Pandey Gaël Cessateur D. Gillotay

Since April 2008, SOLAR/SOLSPEC measures the Solar Spectral Irradiance (SSI) from 166 nm to 3088 nm. The instrument is a part of the Solar Monitoring Observatory (SOLAR) payload, externally mounted on the Columbus module of the International Space Station. As the SSI is a key input for the validation of solar physics models, together with playing a role in the climate system and photochemistry of the Earth atmosphere, SOLAR/SOLSPEC spectral measurements becomes important. In this study, the in-flight operations and performances of the instru- ment -including the engineering corrections- will be presented for seven years of the SOLAR mission. Following an accurate absolute calibration, the SSI variability in the UV as measured by SOLAR/SOLSPEC in the course of the solar cycle 24 will be presented and compared to other instruments. The accuracy of these measurements will be also discussed here.

Payload (computing)

Solar cycle 24

Solar maximum

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A Multi-objective Path–Planning Based on Firefly Algorithm for Mobile Robots

Lecture notes in networks and systems (2023)

Prachi Bhanaria Maneesha Praveen Pandey

Firefly Algorithm

Smoothness

Swarm intelligence

10.1007/978-981-99-5085-0_14

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An Intercomparison of backscatter coefficient at 1064nm from satellite and ground-based measurements over coastal and non-coastal regions

EGU General Assembly Conference Abstracts (2019)

Thaize Baroni Praveen Pandey Jana Preißler Colin O’Dowd

Backscatter (email)

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Epidermoid Cyst of Floor of the Mouth: A Rare Entity

Dental Journal of Advance Studies (2024)

Sujeet Kumar Singh A. Srivastava Praveen Pandey Swatee Agarwal G. S. Naveen Chandra

Dermoid and epidermoid cysts, originating from ectodermal tissue, are benign, slowly growing developmental cysts that can appear anywhere in the body.Just 1.6% of these cysts occur in the oral cavity and less than 7% of them impact the head and neck area.Three histological variations of dermoid cysts that Meyer revised and described in 1955 are the teratoid variant, epidermoid cysts, and dermoid cysts.The ectodermal tissue of the first and second branchial arches which gets entrapped might fuse during the third and fourth weeks of pregnancy and may lead to the development of a midline epidermoid cyst in the floor of the mouth.The sublingual, submaxillary, and submandibular areas are the sites of development, the floor of the mouth being an uncommon location for this condition.A slow-growing intraoral dermoid cyst may increase and obstruct speech or deglutition, or it may represent a compromise to the airway and necessitate prompt surgical surgery.We document a case of a 23-year-old female with an epidermoid cyst clinically appreciable as a large sublingual swelling obstructing swallowing and speech.An intraoral approach was used to surgically incise the pathology.

Epidermoid cyst

Floor of mouth

10.5005/djas-11014-0050

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Estimating Cloud optical thickness from SEVIRI, for air quality research, by implementing a semi-analytical cloud retrieval algorithm

EGU General Assembly Conference Abstracts (2010)

Praveen Pandey Koen De Ridder Stijn Van Looy Nicole Van Lipzig

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