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Search Results: 1 - 10 of 184 matches for " Renuka Gangadharan "
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Kadomstev-Petviashvilli-Burgers (KPB) Equation in a Five Component Cometary Plasma with Kappa Described Electrons and Ions  [PDF]
Manesh Michael, Sreekala Gopinathan, Sijo Sebastian, Neethu T. Willington, Anu Varghese, Renuka Gangadharan, Chandu Venugopal
Journal of Applied Mathematics and Physics (JAMP) , 2015, DOI: 10.4236/jamp.2015.311171
Abstract: We investigate the existence of Ion-Acoustic solitary/shock waves in a five component cometary plasma consisting of positively and negatively charged oxygen ions, kappa described hydrogen ions, hot electrons and cold electrons. The KPB equation is derived for the system; its solution is plotted for different kappa values, as well as for the temperature ratios of ions. It is found that the amplitude of solitary structure increases with increasing kappa values and negatively charged oxygen ion densities. As the temperature of the positively charged oxygen ions increases, the amplitude of solitary wave also increases. We have also studied the dependence of coefficients of the KPB equation on physical parameters relevant to comet Halley.
Negatively Charged Oxygen Ions as a Plasma Diagnostic Tool: Application to Comets  [PDF]
Sreekala Gopinathan, Sijo Sebastian, Noble Abraham, Savithri Devi, Venugopal Chandu, Renuka Gangadharan
Open Access Library Journal (OALib Journal) , 2014, DOI: 10.4236/oalib.1100570
Abstract: We study the stability of the ion-acoustic (IA) wave in a collisional plasma composed of hydrogen, positively and negatively charged oxygen ions, electrons and neutral atoms. This composition approximates very well the plasma environment around a comet. A solution of the dispersion relation yields a frequency for the IA wave at around the hydrogen plasma frequency. The growth/ damping rate is sensitively dependent on the ring parameters u⊥s (the ring speed) and v ts (the thermal spread). The growth rate of the wave, which decreases with increasing collisional frequencies, is larger when u⊥s < v ts . In the presence of negatively charged oxygen ions, the phase and group velocities of the IA wave behave in a contrasting manner when u⊥s < v ts (and viceversa). We propose that this behaviour be exploited as a diagnostic tool for the detection of these ions and also their thermalization.
Synthesis of C-8 alkyl xanthines by pentaamminecobalt(III) complex  [PDF]
Renuka Suravajhala
Advances in Biological Chemistry (ABC) , 2013, DOI: 10.4236/abc.2013.36058
Abstract:

Alkyl xanthines underwent selective homolytic aromatic substitution at C-8 position with alkyl groups of pentaamminecobalt(III) complex. In this process of synthesis, we used monoalkyl hydrazines as the radical source in aqueous ammonia solution. Evidence supporting coordination of the alkyl hydrazine to pentaamminecobalt(III) complex by radical trapping was in good agreement with literature. The products were characterized using GC-MS and 1H, 14N and 59Co NMR spectroscopy.

 

A Subclass of Harmonic Functions Associated with Wright’s Hypergeometric Functions  [PDF]
Gangadharan Murugusundaramoorthy, Kalliyapan Vijaya
Applied Mathematics (AM) , 2010, DOI: 10.4236/am.2010.12011
Abstract: We introduce a new class of complex valued harmonic functions associated with Wright hypergeometric functions which are orientation preserving and univalent in the open unit disc. Further we define, Wright generalized operator on harmonic function and investigate the coefficient bounds, distortion inequalities and extreme points for this generalized class of functions.
Temporal Distribution of Total Column Ozone over Cochin—A Study Based on in Situ Measurements and ECMWF Reanalysis  [PDF]
Vazhathottathil Madhu, Karthika Gangadharan
Open Journal of Marine Science (OJMS) , 2016, DOI: 10.4236/ojms.2016.62016
Abstract: The variability of Atmospheric ozone is very important to understand the radiative balance of the earth-atmospheric system and climate change. In order to understand the temporal variability of total column ozone (TCO) over the coastal station Cochin (9.95°N, 76.27°E), we used the ECMWF (European Centre for Medium-Range Weather Forecasts) reanalysis TCO and ground based measurements using Microtop II Sun Photometer (Ozonometer). The trend, seasonal changes and diurnal variation of ozone concentration have been studied in detail for the period 1981-2014. Cochin is a tropical coastal station with tropical monsoon climate and hence we examined the variability of TCO during pre-monsoon (March-May), monsoon (June-September) and post monsoon (October-December) seasons. Significant variations are noted in the TCO for the different seasons during the period of study. Based on the measurements and analysis, it is observed that TCO is maximum during monsoon and minimum during pre- and post-monsoon. We computed the TCO climatology for pre-monsoon (262.0 DU), monsoon (275 DU) and post-monsoon (253 DU) seasons and found that TCO shows a decadal trend (solar cycle). During monsoon season TCO varies with an increase of approximately 14 DU from the pre-monsoon value and a decrease of 22 DU from the post-monsoon value. The increase in TCO concentration during monsoon may be attributed to the monsoonal wind circulations and organized convection. The validation of ECMWF TCO with in situ measurements using Microtop II Ozonometer has been carried out for the year 2015 and found that the values are positively correlated. The diurnal variability of TCO was examined for vernal and autumnal equinox days and noticed the change in variability.
A Comparative Study of Intra-Seasonal Variability of Total Column Ozone Measured over the Tropical Maritime and Coastal Stations Using Microtop II Ozonometer  [PDF]
Vazhathottathil Madhu, Gangadharan Karthika
Journal of Environmental Protection (JEP) , 2018, DOI: 10.4236/jep.2018.93013
Abstract: The study of temporal and spatial distribution of ozone is very important for understanding the atmospheric chemistry and thereby its impact on environment, weather and climate. The intra-seasonal variability plays a major role in the inter-annual variability of weather parameters such as rainfall, temperature, pressure and atmospheric trace gas constituents such as atmospheric ozone. The strength of monsoon circulation and deep convection greatly modifies the atmospheric compositions and meteorological parameters such as rainfall amount, distributions of atmospheric trace gas concentrations and other weather parameters over the summer monsoon region. The daily total column ozone (TCO) measured over maritime station (Lakshadweep Island— 10°10'N & 73°30'E) and coastal station (Cochin—9°55'N and 76°16'E) using Microtop II Ozonometer were considered for the comparative study of seasonal and intra-seasonal variability for the year 2015. The annual average of total column ozone over Lakshadweep Islands and Cochin was 290 DU and 280 DU respectively for the year 2015. The greater concentrations in daily TCO measurements over Lakshadweep Islands for all seasons compared to Cochin lead to the speculations that, the surface ozone concentration is more because of pollution from the diesel burning emissions, since the whole Island’s population completely depends on diesel generator for the power supply. During winter season maritime station shows a decrease of ~30 DU in TCO over Lak-shadweep Island compared to coastal station Cochin (~18 DU) from the annual mean in the month of December. During pre-monsoon season TCO concentration is high over both locations. There is gradual increase of TCO concentration over Cochin from pre-monsoon to monsoon season and peak in the month of September, but decreasing TCO concentrations measured over Lakshadweep during July to August. In the analysis it was found that Intra-Seasonal Variability (ISV) in total column ozone over Lakshadweep Islands and Cochin during summer monsoon season was modulated by the monsoon dynamics and convection, thereby changes in the photochemistry of ozone production and distributions over the monsoon region. Two significant intra-seasonal oscillations (ISOs) such as Madden Julian Oscillation (MJO) and Quasi-Biweekly Oscillations (QBW) were identified in the TCO during monsoon season. The MJO shows higher periodicity (~54 days) over Lakshadweep Islands compared to the coastal station, Cochin (~48 days). Intra-seasonal variability of TCO over the maritime and coastal stations varies with geographic
STARLIKE FUNCTIONS ASSOCIATED WITH FRACTIONAL
GANGADHARAN MURUGUSUNDARAMOORTHY
Journal of Mathematical Analysis , 2010,
Abstract: Making use of generalized fractional integral operator, we introducea subclass of k
Techniques for multiboson interferometry
Dhevan Gangadharan
Physics , 2015, DOI: 10.1103/PhysRevC.92.014902
Abstract: The quantum statistics (QS) correlations of identical bosons are well known to be sensitive to the space-time extent and dynamics of the particle emitting source in high-energy collisions. While two-pion correlations are most often experimentally measured, the QS correlations of three-pions and higher are rarely explored. We present a set of techniques to isolate and analyze 3- and 4-pion QS correlations. In particular, the technique of built correlation functions allows one to more easily study the effects of quantum coherence at finite relative momenta instead of at the unmeasured intercept of correlation functions.
Sinonasal Undifferentiated Carcinoma—A Case Report  [PDF]
C. Aparna, I. V. Renuka
International Journal of Otolaryngology and Head & Neck Surgery (IJOHNS) , 2014, DOI: 10.4236/ijohns.2014.36068
Abstract: Sinonasal tumors with neuroendocrine differentiation are uncommon. They arise from schneiderian epithelium. The authors reported a case in a fifty-six years old female patient who came with complaints of headache and epistaxis. Differential diagnosis and review of literature are presented in detail. This case is presented in view of its rarity.
Mathematics, Devan, and project work
Renuka Vithal
South African Journal of Education , 2004,
Abstract: I analyse the efforts of one learner, Devan, and a student teacher, Sumaiya Desai, in whose class he participated, as she attempted to realise what may be referred to as a social, cultural, political approach to the school mathematics curriculum through the practice of project work. The focus is specifically on the actions and reflections of Devan as he participated in the project work experience and overturned his casting as a "failing" mathematics learner in a Grade 6 mathematics classroom. I theorise the practice of project work through the data related to Devan and the conceptual tools of project work: problem-orientation; participant-directed; inter-disciplinarity; and exemplarity, and use this framework to organise the structure of this paper. Through this conceptual framing, the challenges and possibilities that such classrooms pose, for learners like Devan but also for the theoretical ideas and associated practice, are made visible and I discuss the potentiality that remained unexplored. South African Journal of Education Vol.24(3) 2004: 225-232
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