NOPR Collection:

A single-input multiple-output voltage-mode second-order universal filter using only grounded passive components

2017-04-01T00:00:00Z

Title: A single-input multiple-output voltage-mode second-order universal filter using only grounded passive components Authors: Yuce, Erkan Abstract: A new single-input multi-output voltage-mode universal filter structure with high input impedance yielding easy cascadability is proposed in this paper. The proposed filter can provide all the standard second-order universal filter responses such as low-pass, band-pass, high-pass, notch filter (NF) and all-pass (AP) responses. NF and AP responses possess low output impedances but they can be obtained through a switch. Each time, one of the NF and AP responses can be obtained. Also, other responses which do not have low output impedances can be obtained simultaneously. The proposed filter uses three plus-type differential difference current conveyors and a minimum number of only grounded passive elements, and does not need any critical passive component matching conditions and cancellation constraints; thus, it is suitable for integrated circuit process. By adding extra one DDCC+ and two grounded resistors, a universal filter with a gain is obtained. Several computer simulations using SPICE program are included to verify the theory. Page(s): 97-106

Free vibration analysis of functionally graded rotating beam by differential transform method

2017-04-01T00:00:00Z

Title: Free vibration analysis of functionally graded rotating beam by differential transform method Authors: Kumar, P Ravi; Rao, K Mohana; Rao, N Mohan Abstract: The growing needs and development of components for industry such as power sector, aerospace, etc. challenge the researchers to implement new methods and concepts to improve functional requirements of structure for enhancing the material strength. Such implementation is especially required in the case of rotating beams that are subjected to critical vibrations under centrifugal forces, large pressure loadings, effect of corrosion, temperature etc. The present paper studies the vibration characteristics of functionally graded rotating Bernoulli-Euler beam, which is symmetric and the material properties vary continuously in thickness direction from core at mid-section to the outer surfaces according to a power law relation. The natural frequencies of these beams are obtained using differential transform method (DTM) formulation. The effect of parameters such as power law index, hub radius and rotational speed on the natural frequencies of functionally graded rotating beam are studied through numerical studies and then compared with results obtained by Rayleigh-Ritz method. Page(s): 107-114

Examination of the effects of burnishing apparatus on surface roughness and hardness in burnishing process

2017-04-01T00:00:00Z

Title: Examination of the effects of burnishing apparatus on surface roughness and hardness in burnishing process Authors: Basak, Hudayim; Sonmez, Fikret Abstract: Burnishing process is a finalization process used to improve the quality of the surface. The advantages of this process is to increase surface hardness and decrease of surface roughness on the surface work-piece on which it is applied, resistance against material fatigue and abrasion resistance. In this study, the design and manufacture of three different apparatus has been realized in order to perform burnishing process by using different parameters (burnishing force, feed rate and number of passes). The effects of these parameters on the Al-6061-T6 material have been examined depending on surface hardness and surface roughness. The test results obtained by the apparatus used in the study are compared with each other. Also the effects of parameters used during burnishing on surface roughness and surface hardness are determined. Finally, the obtained results have been assessed on artificial neural networks (ANN) by using different neuron structures and algorithms, and the obtained data are compared with the test results. Page(s): 115-122

Temperature dependent dielectric behaviour and structural dynamics of PEO-PMMA blend based plasticized nanocomposite solid polymer electrolyte

2017-04-01T00:00:00Z

Title: Temperature dependent dielectric behaviour and structural dynamics of PEO-PMMA blend based plasticized nanocomposite solid polymer electrolyte Authors: Choudhary, Shobhna; Dhatarwal, Priyanka; Sengwa, R J Abstract: Plasticized nanocomposite solid polymer electrolyte (PNSPE) films comprising polymer blend of poly(ethylene oxide) (PEO) and poly(methyl methacrylate) (PMMA) with lithium triflate (LiCF₃SO₃) as a dopant ionic salt, propylene carbonate (PC) as plasticizer and montmorillonite (MMT) clay as inorganic nanofiller have been prepared by classical solution-cast and ultrasonic-microwave irradiated solution-cast methods. The X-ray diffraction study confirms predominantly amorphous phase of these PNSPE films having both the intercalated and exfoliated MMT structures. The dielectric and electrical spectra in the frequency range 20 Hz to 1 MHz of the PNSPE films exhibits the relaxation processes corresponding to charging and discharging of electric double layers in the low frequency region and the cations coordinated polymers chain segmental motion in the high frequency region. The complex dielectric permittivity and ac electrical conductivity increase, whereas the impedance values decrease with the increase of temperature of the PNSPE film confirming the thermally activated dielectric and electrical behaviour of the electrolyte material. The temperature dependent dc ionic conductivity and relaxation times of the PNSPE film obey the Arrhenius behaviour of their activation energy values around 0.3 eV. Dielectric parameters reveal that the ions transportation and ionic conductivity in solid ion-dipolar complexes of the PNSPE films are governed by the values of dielectric permittivity and the relaxation times corresponding to structural dynamics. Results of this study infer that the ultrasonic-microwave irradiation processing used during the sample preparation enhances the dielectric permittivity, structural dynamics and ionic conductivity of the PNSPE film as compared to that of the classical solution-cast method prepared film. The ionic conductivity values of these PNSPE films at ambient temperature are found of the order of 10^–5 S cm^–1 which confirms them as promising electrolyte materials for lithium ion battery and also for all-solid-state ion conducting device applications. Page(s): 123-132