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Wyszukujesz frazę "Pandey, A.K." wg kryterium: Autor


Tytuł:
Quantum Mechanical Studies of Bond and Molecular Polarizabilities of Gas-Phase Metal Halides
Autorzy:
Pandey, A. N.
Bigotto, A.
Gulati, R. K.
Powiązania:
https://bibliotekanauki.pl/articles/1891514.pdf
Data publikacji:
1991-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
31.10.+z
31.90.+s
Opis:
The bond and molecular polarizabilities are studied for the gas-phase metal halides using delta-function potential model of chemical binding on the basis of quantum mechanical approach. The applicability of the model is demonstrated. The contribution of the polarity corrections for the metal halides is thoroughly investigated and it has been found that it plays a significant role for fluorides. Our polarizability calculations resolve the discrepancy about the conformation of the barium dichloride and mercury dichloride and favour the nonlinear structure. Due to lack of experimental results for most of halides of transition metals, the decision whether to incorporate polarity corrections or not remains uncertain at this stage: we must await measurements of more experimental values before we reach any final conclusion. The ionic bond orders have been used for the first time to investigate polarizabilities of monomers and dimers of alkali halides. The results for dimers reveal that polarity contribution is essential for the lithium halides dimers and not for other dimers. The computed results will be asset for the interpretation of experimental measurements.
Źródło:
Acta Physica Polonica A; 1991, 80, 4; 503-520
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electro-Optical Behavior of Dye Doped Nematic Liquid Crystal
Autorzy:
Yadav, S.
Pandey, K.
Misra, A.
Manohar, R.
Powiązania:
https://bibliotekanauki.pl/articles/1505061.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.M-
42.79.Kr
Opis:
We report electro-optical behavior of a dye doped nematic liquid crystal. The dye doped cells have shown some improvement in some parameters important for the display devices such as threshold voltage $(V_{th})$, splay elastic constant, rotational viscosity and response time. The suppression of screening effect improves the threshold voltage for the doped sample.
Źródło:
Acta Physica Polonica A; 2011, 119, 6; 824-828
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assay of the Insensitive High Explosive FOX-7 by Non-Aqueous Titration
Autorzy:
Nandi, A. K.
Paramasivan, P.
Singh, S. K.
Mandal, A. K.
Pandey, R. K.
Powiązania:
https://bibliotekanauki.pl/articles/358156.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
1,1-diamino-2,2-dinitroethene
FOX-7
non-aqueous titration
N,N-dimethylformamide
Opis:
A non-aqueous titration method was developed to assay the insensitive high explosive 1,1-diamino-2, 2-dinitroethene (FOX-7). The weak acidic nature of FOX-7 (pKa 10.6) was exploited in the assay method. The sample was dissolved in the protophilic solvent N, N-dimethylformamide and titrated against sodium methoxide solution in benzene/methanol using azo violet as indicator. FOX-7 samples obtained from regular batch operations were assayed by this method and the results were compared with that of a recrystallized sample. The method is simple, rapid and has good accuracy and precision.
Źródło:
Central European Journal of Energetic Materials; 2012, 9, 4; 343-352
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Formation of Boric Acid by Surface Oxidation of Amorphous Boron Powder: Characterization and Quantitative Estimation
Autorzy:
Nandi, A. K.
Ghosh, M.
Newale, S. P.
Jadhav, A. J.
Prasanth, H.
Pandey, R. K.
Powiązania:
https://bibliotekanauki.pl/articles/358160.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
amorphous boron powder
B2O3
boric acid
FTIR
SEM
EDX
Opis:
Amorphous Boron Powder (ABP) is used as a fuel in air breathing propulsion systems due to its high gravimetric and volumetric heat value. ABP is sensitive to air and undergoes slow oxidation during storage and handling, leading to the formation of a boric acid layer on the particle surface. This paper describes an analytical method for the estimation of boric acid in ABP. In-house samples obtained from the pilot plant of this laboratory, as well as commercial samples, were assayed for their boric acid content. The study is substantiated by characterization of the ABP samples by SEM with EDX and FTIR. The ageing characteristics of in-house boron powder was also studied.
Źródło:
Central European Journal of Energetic Materials; 2012, 9, 4; 387-398
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface Coating of Cyclotetramethylenetetranitramine (HMX) Crystals with the Insensitive High Explosive 1,3,5-Triamino-2,4,6-trinitrobenzene (TATB)
Autorzy:
Nandi, A. K.
Ghosh, M.
Sutar, V. B.
Pandey, R. K.
Powiązania:
https://bibliotekanauki.pl/articles/358361.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
surface coating
cyclotetramethylenetetranitramine
1,3,5-triamino-2,4,6-trinitrobenzene
1,3,5-trichloro-2,4,6-trinitrobenzene
scanning electron microscope
Opis:
A method to crystallize the thermally stable, insensitive high explosive, 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) onto the surface of another high explosive cyclotetramethylenetetranitramine (HMX) crystal is described. Amination of 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) in toluene produces TATB which is precipitated by a reactive crystallization process. When the reaction is carried out in the presence of HMX, TATB crystals are found to be deposited onto the HMX crystal surface. This phenomenon was utilized to obtain in situ surface coating of HMX crystals with TATB. Both the conventional amination and the sonochemical amination methods, using dry ammonia (NH3) gas and ammonium hydroxide (NH 4 OH) respectively as the aminating agents, were studied. The coated materials were characterized by Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), Simultaneous Thermal Analysis (STA) and sensitivity tests. The results were compared with those of the virgin materials. Sonochemical amination provided a uniform coating of the HMX crystals. Coated HMX has shown substantial friction insensitivity gain as compared to uncoated HMX. However there is a drop in impact insensitivity in the coated materials.
Źródło:
Central European Journal of Energetic Materials; 2012, 9, 2; 119-130
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assay of the Insensitive High Explosive 3-Nitro-1,2,4-triazol-5-one (NTO) by Acid-Base Titration
Autorzy:
Nandi, A. K.
Singh, S. K.
Kunjir, G. M.
Singh, J.
Mandal, A. K.
Pandey, R. K.
Powiązania:
https://bibliotekanauki.pl/articles/358351.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
NTO
purity
acid-base titration
HPLC
quality control
Opis:
The insensitive high explosive 3-nitro-1,2,4-triazol-5-one (NTO) is a weak acid (pKa 3.76) due to the labile N–H bond. The weakly acidic character of this compound is exploited for its assay by aqueous acid-base titration. The NTO sample was dissolved in water and the resultant solution was titrated against 0.07 N NaOH solution using phenolphthalein as indicator. Regular batch samples were assayed by this method and the results were compared with those obtained by the HPLC method. The aqueous acid-base titration method was found to be suitable for the quality control of the product.
Źródło:
Central European Journal of Energetic Materials; 2013, 10, 1; 113-122
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamical analysis of stiffened plates under patch loading
Autorzy:
Srivastava, A. K. L.
Pandey, S. R.
Kumar, A.
Powiązania:
https://bibliotekanauki.pl/articles/265921.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
metoda elementów skończonych
obciążenie krawędziowe
częstotliwość drgań
usztywniacz
FEM
partial edge loadings
buckling load
vibration frequency
stiffener
Opis:
The vibration characteristics of stiffened plates with cutouts subjected to in-plane partial edge loadings at one end at the plate boundaries are studied using the finite element method. Buckling loads and vibration frequencies are determined for different cutout ratios and extent of partial edge loading at one end. In the structural modelling, the plate and the stiffeners are treated as separate elements where the compatibility between these two types of elements is maintained. The main elegance of the formulation lies in the treatment of the stiffeners. The stiffeners can be placed anywhere within the plate element, and need not be placed on the nodal lines. The vibration characteristics are discussed and the results are compared with those available in the literature. Numerical results are presented for a range of cutout to plate size from 0 to 0.8.
Źródło:
International Journal of Applied Mechanics and Engineering; 2013, 18, 2; 537-553
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation and characterization of ultrafine RDX
Autorzy:
Pant, A.
Nandi, A. K.
Newale, S. P.
Gajbhiye, V. P.
Prasanth, H.
Pandey, R. K.
Powiązania:
https://bibliotekanauki.pl/articles/358126.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
ultrafine RDX
drowning-out crystallization
BET surface area
SEM
mechanical and electrostatic spark sensitivity
Opis:
This paper describes the synthesis of ultrafine Hexogen (UF-RDX) of size <5μm by drowning-out crystallization. RDX was precipitated from acetone or dimethylformamide (DMF) solution by reducing the solvent power using either a miscible, non-aqueous antisolvent, n-hexane, or an aqueous antisolvent, water containing polyethylene glycol (PEG). Process parameters such as solvent/ antisolvent ratio, agitation, ultrasonication etc. were studied. UF-RDX was characterized for Brunauer-Emmett-Teller (BET) surface area, X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC) and sensitivity tests. In the case of the non-aqueous antisolvent, the precipitated RDX crystals were rod shaped of diameter <1 μm. For the aqueous antisolvent, oval shaped crystals (<5 μm) were precipitated. UF-RDX was found to be more sensitive to impact and less friction sensitive compared to production grade RDX (60-80 μm).
Źródło:
Central European Journal of Energetic Materials; 2013, 10, 3; 393-407
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assay of the thermally stable, insensitive, high explosive 1,3,5-triamino-2,4,6-trinitrobenzene (TATB)
Autorzy:
Nandi, A. K.
Thirupathi, N.
Mandal, A. K.
Pandey, P. K.
Powiązania:
https://bibliotekanauki.pl/articles/358608.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
assay TATB
acid-base titration
base hydrolysis
trinitrophloroglucinol
ammonium chloride
Opis:
An aqueous titration method is described to assay the insensitive, high explosive 1,3,5-triamino-2,4,6-trinitrobenzene (TATB). TATB is initially quantitatively converted to the weak acid 1,3,5-trihydroxy-2,4,6-trinitrobenzene (THTNB) by base catalysed hydrolysis. Subsequently THTNB is assayed by acidbase titration. TATB samples obtained from regular batch operations are assayed by this method, and the results are compared with those obtained by the total amino functional group estimation method using a modified Kjeldhal apparatus. The method is simple and has good accuracy and precision.
Źródło:
Central European Journal of Energetic Materials; 2014, 11, 2; 295-305
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of Ammonium Sulfamate Nitration for the Preparation of Ammonium Dinitramide
Autorzy:
Mandal, A. K.
Kunjir, G. M.
Singh, J.
Adhav, S. S.
Singh, S. K.
Pandey, R. K.
Bhattacharya, B.
Lakshmi Kantam, M.
Powiązania:
https://bibliotekanauki.pl/articles/358022.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Opis:
The reaction kinetics for the preparation of ammonium dinitramide (ADN) is described. ADN is the ammonium salt of the dinitramide anion, and belongs to the group of inorganic oxidizers, mainly useful for energetic rocket propellant formulations, particularly for underwater applications. It is also a potential candidate to replace ammonium perchlorate (AP), in order to develop chlorine-free, green propellants. At HEMRL, ADN is prepared by the nitration of ammonium sulfamate (AS) using mixed acid, followed by hydrolysis, neutralization with ammonia (g) and rectification using solvent. The nitration of ammonium sulfamate (AS) is carried out at a subzero temperature of -40 ±1 °C. The yield of ADN is reliant on the formation of dinitramidic acid, an intermediate product formed during the hydrolysis step, and its stability is predominantly dependent upon the level of acidity and temperature of the reaction medium. Prior to these kinetics studies, process optimization of the nitration of ammonium sulfamate (AS) was performed and gave the final mole ratio of AS:HNO3:H2SO4. Since the nitration of AS is sensitive to temperature, the rate of reaction was studied at fixed temperatures with variation of time, keeping all of the other parameters, such as vessel volume, agitator speed, feed rate etc., constant. During these studies, predetermined quantities of ammonium sulfamate (AS) and mixed acid were allowed to react at a fixed temperature (-40 ±1 °C) for different reaction periods to generate the concentration profile of AS. Using this concentration profile, the reaction order and reaction rate constant were evaluated. In order to find the effect of temperature on the reaction rate and yield, experiments were conducted at other temperatures such as -30 and -50 °C. In the present studies, it was found that the optimum temperature of nitration is -40 ±1 °C and that the rate of reaction follows a pseudo second order process with rate constant 0.01113 (min-1)•(mol/L)-1. The reaction time evaluated for 55 to 60% conversion is about 70-80 minutes at -40 ±1 °C, based on this kinetics. The activation energy of AS nitration was found to be -4.6 kcal/mol, using the reaction kinetic data based on the temperature dependent rate equation derived from Arrhenius’s law.
Źródło:
Central European Journal of Energetic Materials; 2014, 11, 1; 83-97
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Process Optimization for the Gas-Liquid Heterogeneous Reactive Crystallization Process Involved in the Preparation of the Insensitive High Explosive TATB
Autorzy:
Nandi, A. K.
Kshirsagar, A. S.
Thanigaivelan, U.
Bhattacharyya, S. C.
Mandal, A. K.
Pandey, R. K.
Bhattacharya, B.
Powiązania:
https://bibliotekanauki.pl/articles/358228.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
TATB
TCTNB
amination
reaction crystallization
chloride impurity
particle size
Opis:
The thermally stable, insensitive, high explosive 1,3,5-triamino-2,4,6- trinitrobenzene (TATB) is manufactured by amination of 1,3,5-trichloro-2,4,6- trinitrobenzene (TCTNB) in toluene with NH3 gas. It is an isothermal, single-feed, semi-batch, gas-liquid heterogeneous, reaction crystallization process. The amination process is discussed by applying the chemical engineering methodology of mass transfer and reactive crystallization processes based on Two-Film Mass- Transfer (TFMT) theory. Kinetic expressions have been developed to define the chemical reactions as well as the physical phenomena (mass transfer) associated with this process. A single expression has been derived to explain the dependence of the ammonia consumption rate on various process parameters. Subsequently, the influence of various process parameters on the product quality (particle size and chloride impurity content) has been studied on the laboratory scale. Finally, the process has been established in the pilot plant, with optimized process conditions, to realize TATB of desired particle size and chloride content. The effects of feeding excess ammonia, and the presence of mercaptans/hydrogen sulphide impurities in poor quality toluene on the formation of certain undesirable by-products in TATB, are also discussed.
Źródło:
Central European Journal of Energetic Materials; 2014, 11, 1; 31-57
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A report on occurrence of Neofusicoccum sp. in Carallia brachiata (Lour.) Merr. trees from Karnataka, India
Autorzy:
Muthu Kumar, A.
Pandey, A.K.
Mishra, G.
Rao, S.
Powiązania:
https://bibliotekanauki.pl/articles/11572.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Opis:
Carallia brachiata (Lour.) Merr. is one of the soft woody species occurring all along the Western Ghats region of Kundapura, Karnataka, India. The species is considered to be a potent medicinal plant exclusively used against itch and septic poisoning. A study was under gone based on the report of forest department (Karnataka) on mortality of Carallia brachiata. Observation of symptoms on the infected trees and experimental analysis of the samples under laboratory conditions revealed the incidence of Neofusicoccum sp., a first report on Carallia brachiata. This particular Neofusicoccum sp. belongs to Botryospaeriaceae family, and is considered to be an important fungal pathogen associated with tree decline in forest and plantation worldwide.
Źródło:
International Letters of Natural Sciences; 2015, 04
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Global scenario of Acrocarpus fraxinifolius Wight and Arn. - A future tree of Agro forestry
Autorzy:
Mishra, G.
Pandey, A.K.
Arunachalam, M.K.
Rao, S.
Powiązania:
https://bibliotekanauki.pl/articles/11909.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Opis:
Acrocarpus fraxinifolius portrait one among the mainstay of agro forestry in Asian tropics. The lofty tree fortified a substantial impact in every horizon of life. The evergreen, deciduous tree of Fabaceae family stands tall about 30-60 m endowed with unique properties which idiosyncrasies it in the plant kingdom. Surpassing the adverse climatic conditions, A. fraxinifolius serves as a shade tree for tea and coffee plantation and epitomises as a multipurpose avenue tree culminating to the culture of agro forestry. Mundani in bloom is a spectacular appearance bestowed with scarlet crimson red flowers attracting infinite migratory birds and insects. The ancestral gene with indelible memory gravitate this extraordinary majestic tree to aestivate and adapt to strongest survive.
Źródło:
International Letters of Natural Sciences; 2015, 03
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Integrated biostratigraphy of the Jurassic strata of the Wagad Uplift, Kachchh, western India
Autorzy:
Rai, J.
Garg, S.
Gupta, M.
Singh, A.
Pandey, D. K.
Fürsich, F. T.
Alberti, M.
Garg, R.
Powiązania:
https://bibliotekanauki.pl/articles/2077328.pdf
Data publikacji:
2015
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Jurassic
calcareous nannofossils
dinoflagellate cysts
ammonites
Oxfordian
Kimmeridgian
Wagad Uplift
Kachchh
jura
wapienie
bruzdnice
amonity
Oksford
Kimeryd
Opis:
An integrated study based on calcareous nannofossils, organic-walled dinoflagellate cysts, and ammonites from the Washtawa and Kanthkot formations of the Wagad Uplift have allowed a detailed documentation of the stratigraphic position of these formations within the Oxfordian and Kimmeridgian sediments of the Kachchh Basin, western India. The nannofossil assemblages from the lower part of the Nara Shale Member exposed in the Nara and Washtawa domes, the Kanthkot Ammonite Beds along the Trambau River section, and the Patasar Shale Member exposed along the Trambau River section and the Patasar Tank section in the eastern part of the Wagad Uplift belong to the NJ 14 Cyclagelosphaera margerelli Zone of the Early Oxfordian, the NJ 15a Lotharingius sigillatus Zone of the Middle Oxfordian, and the NJ 15b Cretarhabdus conicus of Early Kimmeridgian age, respectively. Zonation schemes, based on calcareous nannofossils, dinoflagellate cysts, and ammonites were calibrated highlighting their biostratigraphic potential. These studies may represent a reference biochronology for Oxfordian–Kimmeridgian age strata applicable to the Tethyan realm of which India was a part during Late Jurassic times.
Źródło:
Volumina Jurassica; 2015, 13, 2; 55--80
1896-7876
1731-3708
Pojawia się w:
Volumina Jurassica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation of Nano Aluminium Powder (NAP) using a Thermal Plasma: Process Development and Characterization
Autorzy:
Pant, A.
Seth, T.
Raut, V. B.
Gajbhiye, V. P.
Newale, S. P.
Nandi, A. K.
Prasanth, H.
Pandey, R. K.
Powiązania:
https://bibliotekanauki.pl/articles/358835.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
nano aluminium
thermal plasma
DC arc plasma
RF induction plasma
aluminium content
BET surface area
HR-TEM
Opis:
A bottom up approach for the preparation of Nano Aluminium Powder (NAP) using a Transferred Arc Thermal Plasma Reactor (TAPR) is described. The aluminium block is subjected to evaporation by the application of a thermal plasma. The aluminium vapour produced is rapidly quenched to room temperature resulting in crystallization of the aluminium vapour in nano-particulate form. Various process parameters, such as the plasma torch power, reactor pressure and plasma gas composition were optimized. This paper also describes the characterization of NAP by analytical methods, for the estimation of the Active Aluminium Content (AAC), Total Aluminium Content (TAC), XRD, bulk density, BET surface area, HR-TEM etc. The results are compared with those for samples prepared in other thermal plasma reactors, such as the DC Arc Plasma Reactor (DCAPR) and the RF Induction Thermal Plasma Reactor (RFITPR), and for commercially available NAP samples (ALEX, prepared by the EEW technique).
Źródło:
Central European Journal of Energetic Materials; 2016, 13, 1; 53-71
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł

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