1,129 research outputs found

    Negative to Positive Magnetoresistance transition in Functionalization of Carbon nanotube and Polyaniline Composite

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    Electrical resistivity and magnetoresistance(MR) in polyaniline(PANI) with carbon nanotube(CNT) and functionalized carbon nanotube(fCNT) composites have been studied for different weight percentage down to the temperature 4.2K and up to magnetic field 5T. Resistivity increases significantly in composite at low temperature due to functionalization of CNT compare to only CNT. Interestingly transition from negative to positive magnetoresistance has been observed for 10wt% of composite as the effect of disorder is more in fCNT/PANI. This result depicts that the MR has strong dependency on disorder in the composite system. The transition of MR has been explained in the basis of polaron-bipolaron model. The long range Coulomb interaction between two polarons screened by disorder in the composite of fCNT/PANI, increases the effective on-site Coulomb repulsion energy to form bipolaron which leads to change the sign of MR from negative to positive.Comment: 5 pages, 8 figures; typos adde

    Characterization of alloy C-276 as a structural material for high-temperature heat exchangers

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    This investigation was focused on characterizing the high-temperature tensile behavior and corrosion susceptibility of nickel-based Alloy C-276, a leading structural material for heat-exchangers in nuclear hydrogen generation. The tensile properties, evaluated at different temperatures, indicate that both the yield strength and ultimate tensile strength were gradually reduced with increasing temperature. However, the ductility parameters were not significantly influenced by the testing temperature. While no failures were observed in stress corrosion cracking (SCC) tests in an acidic solution under a constant-load, the true failure stress (sigmaf) was significantly reduced under a slow-strain-rate condition using both smooth and notched specimens. The critical potentials, determined in a similar environment by an electrochemical method, became more active at the elevated temperature. Cracking was enhanced at anodic and cathodic applied potentials, showing reduced failure strain and sigmaf. The fractographic evaluations of the primary fracture surface revealed dimpled microstructures, indicating ductile failures

    Entropic Stabilization and Descriptors of Structural Transformation in High Entropy Alloys

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    With first-principles theoretical analysis of the local structure using Bond Orientational Order parameters and Voronoi partitioning, we establish (a) HCP\rightarrowBCC structural transformation in high-entropy alloys (HEAs) Nbx_x(HfZrTi)y_y at 16% Nb-concentration, and (b) that the internal lattice distortions (ILDs) peak at the transition. We demonstrate that the relative stability of HCP and BCC structures is driven by energetics, while the overall stability is achieved with contribution from the vibrational entropy that exceeds the configurational entropy of mixing. We show that along with atomic size mismatch, low average number (<< 5) of valence electrons and disparity in the crystal structures of constituent elements are responsible for larger ILDs in Nbx_x(HfZrTi)y_y than in HEAs like Nba_aMob_bWc_cTad_d.Comment: 8 pages, 4 figure

    Hybrid CNN+LSTM Deep Learning Model for Intrusions Detection Over IoT Environment

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    The connectivity of devices through the internet plays a remarkable role in our daily lives. Many network-based applications are utilized in different domains, e.g., health care, smart environments, and businesses. These applications offer a wide range of services and provide services to large groups. Therefore, the safety of network-based applications has always been an area of research interest for academia and industry alike. The evolution of deep learning has enabled us to explore new areas of research. Hackers make use of the vulnerabilities in networks and attempt to gain access to confidential systems and information. This information and access to systems can be very harmful and portray losses beyond comprehension. Therefore, detection of these network intrusions is of the utmost importance. Deep learning-based techniques require minimal inputs while exploring every possible feature set in the network. Thus, in this paper, we present a hybrid CNN+LSTM deep learning model for the detection of network intrusions. In this research, we detect DDOS types of network intrusions, i.e., R2L, R2R, Prob, and which belong to the active attack category, and PortScan, which falls in the passive attack category. For this purpose, we used the benchmark CICIDS2017 dataset for conducting the experiments and achieved an accuracy of 99.82% as demonstrated in the experimental results

    Image Processing Technique for Authentication of Indian Paper Currency

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    As we all know day by day the technology is getting better and better, the production of counterfeit currency has been rapidly increasing. The counterfeit currency problem is faced by almost all countries. Since the real economy is affected, it has affected the economy of the country. Even when the drastic step of demonetization was taken in 2016 to overcome counterfeit currency, this problem did not end.&nbsp; The only one solution for this problem for a common man is to detect the fake currency, by using the fake currency detector machine. These machines are used in banks and large scale business, but for small scale businesses or for a common man&nbsp; these machines are not affordable. There are lot of&nbsp; researches taking place on this matter by using deep learning, image processing and machine learning techniques. This paper&nbsp; gives&nbsp; the complete methodology of fake note detector machine,&nbsp; which is affordable even for a common man.&nbsp; By&nbsp; implementing the applications of image processing&nbsp; techniques&nbsp; we&nbsp; can&nbsp; find &nbsp;out whether&nbsp; the&nbsp; currency&nbsp; notes&nbsp; are&nbsp; fake&nbsp; or not.&nbsp; Image&nbsp; processing&nbsp; technique&nbsp; consists&nbsp; of&nbsp; a&nbsp; number&nbsp; of operations&nbsp; that&nbsp; can&nbsp; be&nbsp; performed&nbsp; on&nbsp; an&nbsp; image,&nbsp; some&nbsp; of&nbsp; which&nbsp; include&nbsp; image&nbsp; segmentation,&nbsp; edge detection,&nbsp; gray&nbsp; scale&nbsp; conversion,&nbsp; pre-processing etc.&nbsp; The&nbsp; proposed&nbsp; system&nbsp; will detect the&nbsp; counterfeit currency of new denominations by distinguishing each denomination based on its size and depending on the features of each currency the comparison takes place. Based on the features matched, it detects whether the currency is counterfeit or not. The system have advantages like simplicity, reliability and cost effective. Which is affordable by a common man since the common man is the one who will be effected most, when the counterfeit currency are circulated in the market because he has to pay the real value of that currency

    Bioefficacy and dissipation of ?-cyfluthrin against white fly Bemisia tabaci Genn.) in okra (Abelomoschus esculentus L.)

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    A field experiment was conducted to evaluate the efficacy of different insecticides viz., bifenthrin, flubendiamide, fipronil, quinalphos, pronofos and ?-cyfluthrin against white fly (Bemisia tabaci) of okra (Abelomoschus esculentus) by spraying twice. Among the insecticides evaluated, ? cyfluthrin at 18.75 g a.iha-1 was found to be the effective by registering 57.00 and 54.21 per cent reduction of whitefly (B. abaci) during first and second sprays, respectively. Further ?-cyfluthrin at 18.75 g a. i ha-1 was subjected to dissipation studies by collecting okra (A. esculentus) fruit samples at interval of zero, one, three, five, seven, 10 and 15 days after last spray. Results of the dissipation studies showed that the initial deposits of ?-cyfluthrin (18.75 g a.iha-1) in okra (A. esculentus) fruit sample was registered to be 0.11 mg kg-1 and dissipated to below detectable level (BDL) within five days after spray

    Mathematical analysis of ESD generated EM radiated fields on electronic subsystem

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    Electrostatic Discharge (ESD) generated Electromagnetic (EM) radiated fields can cause malfunctioning or upsets in an electronic system. This paper presents a mathematical computation of the effects of spatial electric fields from an ESD source. These fields may affect the normal functioning of an electronic system. This work uses a MATLAB program to model the response of Very High Frequency (VHF) amplifier to ESD generated radiated EM fields. The ESD source is a Capacitive Spark Discharge (CSD) source. The transient current element has been modeled as a short dipole. The electric field intensity and the magnetic field intensity have been computed by varying distance along the θ = π/2 direction for the CSD current. The frequency spectra of these E and H fields are obtained by taking Discrete Fourier Transform (DFT). The open circuit voltage induced by ESD generated transient fields at the antenna terminals and the voltage coupled to the input of the VHF amplifier fed by antenna is computed by varying distances. The time domain representation of the real part of the voltage at the output terminals of the VHF amplifier is computed by varying distance from the ESD source. Mathematical computation is carried out to predict the effect of the radiated fields on the induced voltages of a subsystem for various distances from the ESD source

    Sinkholes in Earth Dam Kota Barrage [India]

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    Kota Barrage is the lowermost hydraulic structure amongst the series of four dams built across the river Chambal, a tributary of the river Yamuna in the Ganga Basin. It is situated near the Kota City, Rajasthan in India and is in operation since November, 1960 with an irrigation potential of 679 thousand ha in two adjoining states of Rajasthan and Madhya Pradesh. It comprises of a composite structure consisting of a 268.2m long earth and rockfill dam and a 304.8m long masonry spillway, the total length being 573.0m The earth/rockfill dam abuts in the right against a hillock over which a very old Garh Complex exists and two fort walls intervened in between the spillway and the abutment have divided the dam into three distinct reaches having different foundation sub-strata. The spillway rests on hard quartzitic sand stone with high rock face in the left flank and is provided with 19-radial gates (12 2m x 12.2m each) and 2-under-sluices (2. 7m x 3.3m) to discharge 21240 cumecs at MWL 260.9m. Heavy leakage of water through the bed rock crevices in the adjacent right abutment resting on hillock stope wet spots on downstream edge alongwith repeated settlements and formation of sinkholes on top of the dam has led to a great concern about safety of the dam. Geo-technical investigations carried out recently revealed some lenses/zones with low density soilmass and higher permeability at places in the embankment

    Temperature dependent study of thermophysical properties of binary mixtures of 1,4-butanediol + picolines

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    The experimental values of densities (r) and speeds of sound (u) of (1,4-butanediol + α-, orβ- picoline) binary mixtures have been used to calculate the internal pressure (πi), free volume (Vf), enthalpy (H), entropy (Ts), excess internal pressure (πiE), excess free volume (VfE), excess enthalpy (HE), excess free energy (GE) and excess entropy (TsE) at temperatures 303.15, 308.15, 313.15 and 318.15K over the entire composition range. The results have been discussed in terms of molecular interactions due to physical, chemical and structural effects between the unlike molecules. It has been observed that the strength of intermolecular interaction between 1,4-butanediol and picoline molecules is in order ɑ-picoline&gt;β-picoline

    Trends in the Epidemiology of Hepatitis B Virus and Hepatitis C Virus Infections at a Tertiary Care Hospital in East Delhi: A 7-Year Retrospective Analysis

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    Hepatitis B virus (HBV) and Hepatitis C virus (HCV) infections are major global health problems. In 2009, the national Integrated Disease Surveillance Programme (IDSP) began conducting surveillance across all Indian states for epidemic-prone diseases including viral hepatitis. Hence this retrospective study was conducted to identify trend changes in HBV and HCV epidemiology over a period of 7 years at a tertiary care hospital in Delhi. Enzyme-linked immunoassay result entries for Hepatitis B surface antigen (HBsAg) and Hepatitis C antigen and/or anti-HCV antibody were analyzed. The 7-year seroprevalence of HBV and HCV was found to be 3.084% and 5.381% respectively. The seroprevalence of HBsAg was maximum in 2010. Since then the seroprevalence has shown a small decrease. Government of India has included HBV vaccine in the National Universal Immunization Program in the entire country in 2011-12. We consider the reduction in HBsAg seroprevalence to represent a true fall in HBV transmission due to vaccination and/or public consciousness. In the present study, HCV infection appeared to be more common than HBV infection. During last few years, seroprevalence of HCV also increased, which is possibly attributable to an increase in the population of Delhi and a heavy load of the migrant population. These figures may be important for estimation of the disease burden in this region. The study provides a fine reference for future studies, because of the large number of cases investigated over a long period of 7 years and draws attention to the lacunae in ongoing immunization programs
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