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Minaei, Shahram (Dogus Author) In this paper, new analog memristor emulator circuits based on current backward transconductance amplifier (CBTA) and passive elements are proposed. They emulate both types of memristor (incremental and decremental) just by interchanging the CBTA output terminals. It uses only one CBTA, two resistors, one capacitor and one multiplier emulating grounded memristor. They consist of less CMOS transistors and have wider output ranges compared to other designed emulator circuits. The CMOS implementation of the CBTA using 0.18 ttm level-7 TSMC CMOS technology parameters is also proposed. It uses 23 CMOS transistors operating with the +/- 0.9 V DC supply voltage. Theoretical derivations and related results are validated using SPICE simulations.

In this study, a novel lead and lag type compensator circuit is proposed using a single active component, namely, the current feedback operational amplifier (CFOA). The proposed circuit has only one CFOA, two grounded resistors and two grounded capacitors. The input impedance of the proposed compensator is designed to be high whereas the output impedance is low. In terms of input and output impedance values, the proposed topology is suitable for a cascade connection with the voltage-mode structure not requiring buffer circuits, both at the input and output of the circuit. Moreover, the proposed circuit offers the advantage of controlling the poles and zeros orthogonally. The non-ideal effects depending on the active component are also presented in the paper. The commercially available AD844 integrated circuit component was used as the CFOA component in the proposed lead and lag compensator circuit and circuit simulations were performed using PSpice. Moreover, the electrical performance of the circuit was demonstrated by experimental studies. The achieved theoretical, simulation and experimental results are given with a comparison. Finally, a closed-loop control system application was given using the proposed compensator circuit and the operation of the circuit was demonstrated with PSpice simulations.

In this work, a CBTA-based universal mutator circuit is proposed for the realization of memcapacitor and meminductor elements. Proposed mutator circuit contains only one CBTA element, one memristor and one capacitor. It is suitable to transform a grounded memristor to a floating memcapacitor or meminductor. SPICE simulation by using a CBTA designed with 0.18 μm level-7 TSMC CMOS transistors was performed to show the accuracy of the proposed circuit and as a result, frequency dependent hysteresis loops are obtained.

Frictional heating of articulating surfaces may influence the rate of wear, fatigue, creep and oxidative degradation of bearing materials. Also temperature rise can damage the surrounding tissue and lubricant around the artificial joint and contributes insert loosening. The objective of this study is to determine temperature rise between sliding surface of vitamin E blended UHMWPE and conventional UHMWPE acetabular component paired with a cobalt–chromium–molybdenum (CoCrMo) femoral component, as a function of sliding time and applied load. Besides the experimental studies, the frictional temperature rise of conventional UHMWPE was theoretically calculated. Frictional measurements of the joints were carried out on a custom made hip joint friction simulator. The diameter of the prostheses was 28 mm. Applied static loads were changed from 200 N to 1500 N. In flexion–extension plane, a simple harmonic oscillatory motion between ±24° was applied to the UHMWPE acetabular component. The period of motion was 1 Hz and the tests were run up to 11,000 cycles. Temperature rise in acetabular and femoral component was recorded with embedded thermocouples. Both the experimental temperature rise values and theoretical calculations results were compared and evaluated.

WOS: 000305815300015, In this study, a novel second order universal filter using current-feedback amplifier, commercially available active component, is presented. The signal-flow graph method is used to synthesize the filter. The proposed filter has three high impedance input and one output, (multiple input single output (MISO) configuration). It can generate all biquadratic filtering functions namely: low-pass (LP), band-pass (BP), high-pass (HP), band-reject (BR) and all-pass (AP) at the output terminal by selecting different input signal combinations. The validity of the proposed circuits is demonstrated by simulations. (C) 2011 Elsevier GmbH. All rights reserved.

A general synthesis procedure is given for a versatile signal flow graph realization of a general current transfer function by using multi-output second generation current controlled current conveyors (MO-CCCIIs). The proposed configuration uses n + 1 multi-output second generation current conveyors (MO-CCIIs), n capacitors and at most 2 ( n + 1 ) resistors. This number of resistors can be reduced to n for special cases. Using MO-CCCIIs instead of MO-CCIIs, the resistors can be removed completely for the n th-order universal structure. The general transfer function having any numerator dynamics can be derived from the universal structure by using a single MO-CCCII and at most n + 1 resistors. It is very easy to find the values of the passive elements from the coefficients of the transfer function to be realized. The validity of the proposed synthesis is verified through PSpice simulations.

A general synthesis procedure is given for a versatile signal flow graph realization of a general transfer function by using current differencing buffered amplifier (CDBA). The proposed configuration uses n + 1 CDBAs, n capacitors and at most 2 n + 4 resistors. This number of resistors can be reduced to n + 1 for special cases. The circuit is eligible to obtain a variety of transfer characteristics with the same common denominator polynomial, and it is easily converted to different modes of operations. It is straightforward to find the values of the passive elements from the coefficients of the transfer function to be realized. Simulations results are obtained by using commercially available active component AD844 and CMOS technology as well. All of these make the proposed circuit attractive.

WOS: 000298836500016, …