Mitigation of CM Conducted Emi in Flyback Converter Using Balancing Capacitors

The offline Switched Mode Power Supply (SMPS) draw non-sinusoidal line current from the utility power supply, thereby introducing unwanted harmonics and also generate significant electromagnetic interference (EMI). Power factor correction (PFC) converters can be used to improve the power factor. But they also generate EMI in both Differential Mode (DM) and Common Mode (CM). In this paper, the EMI generated by the flyback PFC converter is addressed. A lumped circuit model for CM conducted EMI generated in a flyback converter, including the HF transformer's parasitics and the components, is considered. The parasitics of the HF transformer are calculated and measured experimentally. Using them, the resonant frequencies of the flyback converter are calculated for validation. A technique for determining the required balancing capacitor to mitigate CM conducted EMI is presented. A novel technique by splitting this balancing capacitor with their mid-point grounded for further reduction of this EMI is presented. This technique can eliminate the $C_y$Cy capacitors of the EMI line filter connected between line/neutral to the ground. Hence for the same amount of CM conducted EMI mitigation, the size and the cost of EMI line filters are reduced. Theoretical analysis, simulation results, and experimental verifications are presented

On Tests for Special Two-Sample Location Problem Based on Subsample Minimum and Median

Shetty and Umarani(2005) considered a special type of two-sample location problem which has some potential applications, particularly in comparing the performances of two packing machines. In this paper, a new class of test statistics is proposed which is based on sub-sample minima of first sample and sub-sample median of second sample. The performance of members of the new class is evaluated in terms of Pitman asymptotic relative efficiency in comparision with Shetty and Umarani(2005). It can be concluded that the performance of the new proposed class of tests is better for medium and heavy tailed distributions such as Normal, Logistic, Laplace and Cauchy. For light tailed distributions the performance of new testis better in specific cases. It is proved that the test is consistent for one-sided alternatives

Dynamic Computation of Threshold Value for Classifying Jobs in Cloud Computing for Efficient Resource Utilization

Cloud computing is an instant use of resources and it is a trending technology in the field of computer science. Here, many jobs will be arriving continuously with different job size, at that point of time, allocating of resources for suitable virtual machines without allowing virtual machine to starving is a hindrance job. So, to avoid this hindrance, an algorithm Dynamic Computation of Threshold Value is proposed (DCTV) and based on the threshold value the jobs are classified in the initial stage, so this classification leads to allocation of resources precisely and efficient resource utilization. The experimental result shows that by using dynamic computation of threshold value the allocation of resource time is reduced and classification accuracy is improved compared to manual computation of threshold value

Electrochemical and Photocatalytic Applications of Ce-MOF

We report on the applicability of an easy and general synthesis procedure for the formation of Ce(IV)-MOFs. Cerium-based metal–organic frame (Ce-MOF) was successfully synthesized by a simple, cost-effective and green route. Highly homogeneous topology, nano-sized crystals, stable oxidation states Ce(III) and Ce(IV) at room temperature, significant surface area and thermal stability up to 320$^{\circ}$C are the notable properties achieved by Ce-MOF. Electrontransferability of the cerium electrode was used for the detection of methylene blue (MB) analyte in acidic buffer solution. Also the effect of different pH buffer solutions on electrode response has been studied. Photocatalytic performance of nano-Ce-MOF was studied on the degradation of MB analyte under visible light

Phytochemical Analysis and Evaluation of Antibacterial Activity of Different Extracts of Soil-Isolated Fungus Chaetomium Cupreum

Background: Chaetomium cupreum is soil-isolated pigment-producing fungus used as biocontrol agent. Hypothesis: The aim of the present study was to evaluate the bioactive constituents and antibacterial potential of C. cupreum extracts on bacteria such as Staphylococcus aureus, Bacillus subtilis, Salmonella typhi, and Proteus vulgaris. Materials and Methods: The qualitative and quantitative screening of secondary metabolites was done by standard procedures. The antibacterial activity of different extracts of C. cupreum was determined by agar well diffusion method and broth microdilution methods. Results: Among the different extracts of C. cupreum, ethyl acetate and n-butanol extracts exhibited antibacterial activity. In the n-butanol extract, the most susceptible organism was found to be B. subtilis with zone of inhibition 18.5 ± 0.7 mm, followed by P. vulgaris 15.5 ± 0.7 mm, S. typhi 12.5 ± 3.5 mm, and S. aureus 12.0 ± 2.8 mm at 0.5 mg/ml, whereas in the ethyl acetate extract, the most susceptible organism was to found be P. vulgaris with zone of inhibition 17.5 ± 0.7 mm followed by B. subtilis 17.0 ± 1.4 mm, S. typhi 14.0 ± 0.7 mm, and S. aureus 13.5 ± 0.7 mm at 0.5 mg/ml. Conclusion: The obtained results suggest that C. cupreum extracts contain compounds that possess antibacterial activity

One-Pot Synthesis of 1,4-Dihydropyridine Derivatives and their X-Ray Crystal Structures: Role of Fluorine in Weak Interactions

1,4-dihydropyridines, namely diethyl 4-(4-fluorophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (1a), diethyl 2,6-dimethyl-4-(3,4,5-trimethoxyphenyl)-1,4-dihydropyridine-3,5-dicarboxylate(1b), and diethyl 4-(3,4-dimethoxyphenyl)-2,6-dihydroxy-2,6-bis(trifluoromethyl)piperidine-3,5-dicarboxylate (2), are synthesized by one-pot multicomponent condensation of aromatic aldehyde with ethyl acetoacetate and liquid ammonia in the presence of an ethanol-water mixture and are characterized by single crystal X-ray diffraction. The effect of a fluorine atom on the dihydropyridine nucleus give insight into the self-assembly of compounds with various types of non-covalent interactions that greatly affect the crystal packing

Process-Induced Variability Modeling of Subthreshold Leakage Power considering Device Stacking

The dominance of leakage currents in circuit design has been impelled by steady downscaling of MOSFET into nanometer regime, and has become a significant component of total IC power dissipation. The issue is further aggravated with the inability to gauge the tolerance of process parameters around their nominal value. Consequently, the drive to improve the static power prediction has enticed accurate and reliable modeling of leakage current, specifically for ultralow power applications. In contrast to gate- and band-to-band-tunneling leakages, subthreshold leakage exhibits high susceptibility to process variations and hence has been considered for variability modeling. Fluctuations in the device electrical and geometry parameters result in a wider distribution of subthreshold leakage current. Hence, taking into account stacking effect, an analytical variability model to estimate subthreshold leakage power in subthreshold circuits, in the presence of threshold voltage variations is proposed. Further, the impact of threshold voltage variability on subthreshold leakage power is modeled in conjunction with simultaneous variations in gate length and width. The leakage power variability is characterized by model-generated distributions obtained using Monte Carlo analysis and validated against SPICE simulations. The proposed model is about 700× computationally faster than SPICE simulations with mean error being less than 0.19%. In this paper, an analytical variability model to estimate subthreshold leakage power in the presence of threshold voltage variations is proposed. The impact of threshold voltage variability on subthreshold leakage power is modeled in conjunction with simultaneous variations in gate length and width. The leakage power variability is characterized by model-generated distributions obtained using Monte Carlo analysis and validated against SPICE simulations. The proposed model is about 700× computationally faster than SPICE simulations with mean error being less than 0.19%

Effect of Rare Earth Oxide Nanoparticles on the Photoluminescence and Conductivity Properties of Pva Films

Nanoparticles of Gd2O3 and Sm2O3 were prepared by solution combustion method. Nanocomposite films of PVA-Gd2O3 and PVA-Sm2O3 were prepared by solution casting method. These were characterized by XRD to give the nanocrystallite size as 19nm and 30nm respectively and to confirm the formation of a composite while TEM gave nano-particle size as 26nm and 37nm respectively. Both nanocomposites showed good photoluminescence. Impedance measurements showed that the conductivity decreased in the nanocomposites compared to PVA and that Correlated Barrier Hopping was the probable mechanism for conduction in both nanocomposite films. The fitting of the electric modulus to KWW equation indicated a non-Debye type of relaxation in both these films. The relaxation time decreased with increasing temperature in both nanocomposites

Molecular Characterization of some Whitefly Species from India

Whiteflies (Hemiptera: Aleyrodidae) are polyphagous pests causing economic losses in many crops. Many species of whiteflies exhibit intraspecific variations/ species complexes and it is important to analyse their genetic variations using molecular markers. This study analyses the partial mitochondrial COI (mtCO1) gene (658bp), sequenced from some whiteflies collected through surveys across 12 locations in India. The comparison of these sequences in the NCBI database, and their BLAST and ORF analyses were accomplished. These revealed the presence of a new sequence from a sample collected on custard apple (Annona reticulata) identified as Pealius nagerkoilensis. The other six groups were observed to belong to Aleurodicus rugioperculatus, Aleurocanthus sp., Aleuroclava sp., Bemisia tabaci, an Aleyrodidae sp., and Aleurodicus dispersus. Thus, the present study determines the genetic diversity in some whiteflies facilitating the identification of species and their complexes