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Search Results: 1 - 10 of 140845 matches for " Ajay K Gautam "
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Efficacy of Triphala Churn ingredients against A. niger and potential of clove extract as herbal fungitoxicant
Ajay K Gautam
Biology and Medicine , 2010,
Abstract: The present study explores the association of Aspergillus niger with stored raw and powdered ingredients ofTriphala Churn, which is a 1:1:1 proportional combination of Emblica officinalis Gaertn. (Amla), Terminaliabellerica (Gaertn.) Roxb. (Baheda), and Terminalia chebula Retz. (Harada) respectively. Total 106 stored fruitsand 68 powdered samples of E. officinalis, T. bellerica and T. chebula, have been analysed for their fungalassociation, if any. Results revealed that among all the fungal isolates, A. niger was found to be a frequentlyoccurring species as well as a major contaminant. Therefore, present investigation was carried out to study theefficacy of aqueous extracts of fruits (fresh & dry) and a powdered ingredient of Triphala churn against the growthof A. niger. In addition, an effort has been made to evaluate the antifungal potential of aqueous extracts ofSyzygium aromaticum (L.) Merril & Perry (Clove), Cinnamomum zeylanicum Blume (Cinnamon), and Zingiberofficinale Roscoe (Ginger) as herbal fungitoxiants, to control the growth of A. niger. During the investigation ofsamples for fungal contamination, highest percent frequency (93.10%) of A. niger was recorded. It was observedthat none of the aqueous extracts of fruits and powdered ingredient of Triphala churn was found effective againstthe growth of A. niger. However, the aqueous extract of Clove was found strongly effective to inhibit the growth ofA. niger completely at 20% concentration (v/v). Among the other extracts Cinnamon showed 24.73% inhibition,whereas Ginger extracts was observed to be ineffective against A. niger. Hence, the aqueous extract of Clovecan be utilized as herbal fungitoxicant to control the growth of A. niger.
Antifungal Potential of Triphala Churna Ingredients against Aspergillus Species Associated with Them During Storage
Ajay K. Gautam,Shubhi Avasthi,Anu Sharma,Rekha Bhadauria
Pakistan Journal of Biological Sciences , 2012,
Abstract: The present study describes the antifungal potential of fruit and powdered ingredients of triphala churna, i.e. Emblica officinalis (Garetn.) (Amla), Terminalia bellirica (Gaertn.) Roxb. (Baheda) and Terminalia chebula (Retz.) (Harada), collected from the market of Gwalior (M.P.), India. Water extracts of all the fruits and powdered samples were tested (in vitro) for their antifungal activities by poisoned food technique against different Aspergillus species (A. flavus, A. fumigatus, A. versicolor, A. terreus and A. niger) associated with them during storage. All extracts displayed varied levels i.e. very low to very high antifungal activities on four Aspergillus species. The aqueous extracts of fresh fruits (37.96±7.59%) was observed to be most effective than dry fruits (34.95±7.59%) and powder (25.07±6.05%). Terminalia chebula (fresh and dry) extracts were found most active against the four Aspergillus species with 49.15 and 40.8% inhibition, respectively. None of the extracts were found effective against the growth of A. niger. All fruits and powdered aqueous extracts were observed to be ineffective against the A. niger. The variability in antifungal activity of aqueous extracts in the present study may be useful to study the relationship between antifungal potential of herbal drugs and prevalence of fungal contaminant during their storage.
Synthesis of Thinned Planar Circular Array Antennas Using Modified Particle Swarm Optimization
Narendra Nath Pathak;Gautam Kumar Mahanti;Shashank K. Singh;Jitendra Kumar Mishra;Ajay Chakraborty
PIER Letters , 2009, DOI: 10.2528/PIERL09090606
Abstract: In this paper, the authors present an optimization method based on modified Particle Swarm Optimization (PSO) algorithm for thinning large multiple concentric circular ring arrays of uniformly excited isotropic antennas that will generate a pencil beam in the vertical plane with minimum relative side lobe level (SLL). Two different cases have been studied, one with fixed uniform inter-element spacing and another with optimum uniform inter-element spacing. In both the cases, the number of switched off elements is made equal to 220 or more. The half-power beam width of the synthesized pattern is attempted to make equal to that of a fully populated array with uniform spacing of 0.5 . Simulation results of the proposed thinned arrays are compared with a fully populated array to illustrate the effectiveness of our proposed method.
History and metastability effects in the intermediate state of mesoscopic type I superconducting Indium
Ajay D. Thakur,Ujjal K. Gautam,Goutam Sheet,Tomonobu Nakayama,Yoshio Bando,Dmitri Goldberg,Shuuichi Ooi,Kazuto Hirata
Physics , 2010,
Abstract: We report detailed magnetic measurements on history and metastability effects in the intermediate state of mesoscopic cylinders of type I superconducting Indium. This includes the observation of topological hysteresis with the signature occurrence of different critical fields during flux entry and flux exit. We show the existence of a plethora of metastable configuration and recipes to access them. We also demonstrate the manifestation of superheating and supercooling of superconducting and normal states, respectively across the superconductivity transition.
Phase-Only and Amplitude-Phase Only Synthesis of Dual-Beam Pattern Linear Antenna Arrays Using Floating-Point Genetic Algorithms
Gautam Kumar Mahanti;Ajay Chakraborty;Sushrut Das
PIER , 2007, DOI: 10.2528/PIER06072301
Abstract: In this paper, we present a comparison study between phase-only and amplitude-phase synthesis of symmetrical dual-pattern linear antenna arrays using floating-point or real-valued genetic algorithms (GA). Examples include a sum pattern and a sector beam pattern. In the former, phase is only optimized with predetermined Gaussian amplitude distribution of fixed dynamic range ratio (|max min|) and in the latter, both are optimized with less dynamic range ratio than the former and yet share a common amplitude distribution.
Relevance of Twin Deficit Hypotheses: An Econometric Analysis with Reference to India  [PDF]
Suresh K.G., Vikas Gautam
Theoretical Economics Letters (TEL) , 2015, DOI: 10.4236/tel.2015.52036
Abstract: Current study examines the relevance of twin deficit hypothesis in Indian context by considering the endogenously determined structural breaks in both unit root and cointegration tests. The cointegration analysis shows that there is no long term relationship between the study variables. But the Granger causality test results indicate that bidirectional granger causality is running between the variables. Results showed no long run relationship between the variables; twin divergence in the long run, while in the short term, variables are related. The findings of the study are based on data for the period 1973-1974 to 2013-2014.
On Channel Estimation of OFDM-BPSK and -QPSK over Generalized Alpha-Mu Fading Distribution  [PDF]
Neetu Sood, Ajay K. Sharma, Moin Uddin
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2010, DOI: 10.4236/ijcns.2010.34048
Abstract: This paper evaluates the performance of OFDM-BPSK and -QPSK system in α-µ distribution. A fading model which is based on the non-linearity present in the propagation medium is utilized here for generation of α-µ variants. Different combinations of α and µ provides various fading distributions, one of which is Weibull fading. Investigations of channel estimation schemes gave an idea of further reducing the BER as to improve the performance of OFDM based systems. In flat fading environment, channel estimation is done using phase estimation of the transmitted signal with the help of trained symbols. Final results show the improvement in BER. However, the amount of results improved depends upon the amount of trained symbols. The more trained symbols will result into more improved BER.
Analysis of the Impact of P-Ratio on BER, Q-Factor and OSNR of Radio over Fiber (RoF) System  [PDF]
Vishal Sharma, Amarpal Singh, Ajay K. Sharma
Optics and Photonics Journal (OPJ) , 2011, DOI: 10.4236/opj.2011.14029
Abstract: The impact of p-ratio i.e. ratio of carrier power to total received RF power at control office (CO) on Bit error rate (BER), Q- performance parameter and Optical signal noise ratio (OSNR) of RoF communication system is theoretically analyzed using angular full-linewidth at half maximum (FWHM) of Lorentzian shape for the RF oscillator in this paper. As reduction in Laser linewidth improves the performance of RoF system, the RF oscillator linewidth at FWHM also plays an important role in improving the performance of RoF system.
Performance Analysis of WDM RoF-EPON Link with and without DCF and FBG  [PDF]
Baljeet Kaur, Ajay K. Sharma, Vinod Kapoor
Optics and Photonics Journal (OPJ) , 2013, DOI: 10.4236/opj.2013.32027

Performance of WDM ethernet passive optical network (EPON) with radio over fiber (RoF) optical link has been analyzed with the use of dispersion compensating fiber (DCF) and fiber bragg grating (FBG) to compensate the dispersion and four wave mixing. With the use of DCF and FBG, performance of the system is improved by 77.67%. Results are compared with and without DCF + FBG for different optical power and fiber length. The BER, Q factor and eye diagrams have been obtained for evaluating the performance of the system.

Current Mode Universal Filter Using Single Current Controlled Differential Difference Current Conveyor Transconductance Amplifier  [PDF]
Ajay Kumar Kushwaha, Sajal K. Paul
Circuits and Systems (CS) , 2015, DOI: 10.4236/cs.2015.610023
Abstract: This research paper contains a new electronically tunable current-mode biquadratic universal filter using a new active building block; current controlled differential difference current conveyor transconductance amplifier (CCDDCCTA). The proposed filter provides the following important and desirable features: (i) One can use only one CCDDCCTA and two capacitors; (ii) One can get low pass (LP), band pass (BP), high pass (HP), notch (NF) and all pass (AP) current responses from the same configuration without any alteration; (iii) Passive components are grounded, which ease the integrated circuit implementation; (iv) Responses are electronically tunable; and (v) Sensitivity is low. Moreover, the non-ideality analysis shows that the parasitic passive components can be compensated for the proposed circuit. The functionality of the design is verified through SPICE simulations using 0.25 μm CMOS TSMC technology process parameters. Simulation result agrees well with the theoretical analysis.
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