Characterization and Electrical Conductivity of Electron Beam Irradiated Metal Phthalocyanine Complexes

Variation of DC electrical conductivity with temperature from 273-473 K of electron beam irradiated Tetra-nitro zinc, and Cu-Pcs,   were carried out. It   shows semiconductor behavior and resistivity varies from 0.043×10 5 Ω -cm to 64.61×10 5 Ω -cm for all complexes. Variation of conductivity with temperature shows two straight lines of different slopes the first line (LT), resembles the α– phase, (Ea 1 ) = 0.226 eV while the second line at 362 K resembles the β - phase (Ea 2 ) = 0.460 eV (for Cu- Pcs). The β -phase shows higher activation energy than the α -phase, and the X-ray diffraction studies reveal that the crystals are monoclinic. The conductivity is explained on the basis of Davis and Mott model. The conduction mechanism at lower temperature is explained in terms of hoping through a band of localized states and at higher temperatures in terms of thermal excitation of carriers to the band edge

Limited Data Speaker Verification: Fusion of Features

The present work demonstrates experimental evaluation of speaker verification for different speech feature extraction techniques with the constraints of limited data (less than 15 seconds). The state-of-the-art speaker verification techniques provide good performance for sufficient data (greater than 1 minutes). It is a challenging task to develop techniques which perform well for speaker verification under limited data condition. In this work different features like Mel Frequency Cepstral Coefficients (MFCC), Linear Prediction Cepstral Coefficients (LPCC), Delta (4), Delta-Delta (44), Linear Prediction Residual (LPR) and Linear Prediction Residual Phase (LPRP) are considered. The performance of individual features is studied and for better verification performance, combination of these features is attempted. A comparative study is made between Gaussian mixture model (GMM) and GMM-universal background model (GMM-UBM) through experimental evaluation. The experiments are conducted using NIST-2003 database. The experimental results show that, the combination of features provides better performance compared to the individual features. Further GMM-UBM modeling gives reduced equal error rate (EER) as compared to GMM

Trust correlation of mobile agent nodes with a regular node in a Adhoc network using decision-making strategy

A mobile agent offers discrete advantage both in facilitating better transmission as well as controlling the traffic load in Mobile Adhoc Network (MANET). Hence, such forms of network offers maximized dependencies on mobile agents in terms of its trust worthiness. At present, there are various work being carried out towards resisting security breach in MANET; however approaches using mobile agent based mechanism is few to found. Therefore, the proposed system introduces a novel mathematical model where an extensive decision making system has been constructed for identifying the malicious intention of mobile agents in case they go rogues. By adopting multi-tier communication policy and fairness concept, the proposed system offers the capability to resist any form of malicious activity of mobile agent without even presence of any apriori information of adversary. The outcome shows proposed system outshines existing security scheme in MANET

Novel framework using dynamic passphrase towards secure and energy-efficient communication in MANET

At Mobile Adhoc Network (MANET) has been long-researched topic in adhoc network owing to the associated advantages in its cost-effective application as well as consistent loophopes owing to its inherent charecteristics. This manuscript draws a relationship between the energy factor and security factor which has not been emphasized in any existing studies much. Review of existing security approaches shows that they are highly attack specific, uses complex encryption, and overlooks the involvement of energy factor in it. Therefore, the proposed system introduces a novel mechanism where security tokens and passphrases are utilized in order to offer better security. The proposed system also introduces the usage of an agent node which communications with mobile nodes using group-based communication system thereby ensuring reduced computational effort of mobile nodes towards establishing secured communication. The outcome shows proposed system offers better outcome in contrast to existing system

Thermal expansion of irradiated polyvinyl chloride from 10 K to 340 K

The coefficient of thermal expansion is measured for irradiated Polyvinyl Chloride (PVC) from 10K to 340K. The samples of PVC are irradiated, up to 500 Mrad in steps of 100 Mrad, in air at room temperature by using Co gamma rays with a dose rate of 0.3 Mrad/h. The PVC is an amorphous sample which is confirmed by X-ray diffraction. The coefficient of thermal expansion is found to decrease with radiation dose from 10K to 110K and it increaseswith radiation dose from 110K to 340K. The results are explained on the basis of radiation induced degradation of the sample

Thermal expansion of irradiated polyethylene from 10 to 340 K

The coefficient of thermal expansion of γ-irradiated polyethylene has been measured from 10 to 340 K by using the three-terminal capacitance technique. The samples are irradiated to 500 Mrad in steps of 100 Mrad in air at room temperature with γ-rays from a Co<SUP>60</SUP> source at a dose rate of 0.3 Mrad/h. The crystallinity of the sample is measured by X-ray diffraction. The crystallinity is found to decrease with radiation dose. The thermal expansion coefficient is found to be constant with radiation doses from 10 to 110 K and decreases with doses from 110 to 340 K

Electrical conductivity and microcrystalline parameter in Co-Zn ferrites

A series of samples of the system Co(1-x)Zn(x)Fe(2)O(4) (for x=0.0, 0.2, 0.4, 0.6 and 1.0) were prepared by usual ceramic technique. These prepared samples were examined using X-ray powder pattern, which confirms the presence of a spinel structure. The authors have also carried out line profile analysis of individual Bragg reflections observed in these ferrites, which shows variation in the cell parameter. Further electrical conductivity measurements of these ferrites were carried out as a function of temperature. The observed values of the electrical conductivity have been explained on the basis of Verwey's hopping mechanism. The activation energy was found to decrease with increasing Zn content. In addition, its variations for varying concentrations of Zn in Co are interpreted in terms of microstructural parameters