Forced convection heat transfer from porous heat sinks placed in partially open cavity: Some case studies

In this present study, the forced convection heat transfer from aluminum foam heat sinks with 10, 20, 40 PPI pore density placed in a discrete form in a partially open cavity were experimentally investigated. Air was used as working fluid. The uniform heat flux was applied to 3 × 3 array of foam heat sinks horizontally mounted in the cavity. The experimental studies were performed for the 3363–9743 range of Reynolds number and the 2.7 x 10⁶ and 7.5 x 10⁶ range of modified Grashof number. The effects of the Reynolds number, the modified Grashof number and the pore density of foam heat sink on the heat transfer were investigated. The results obtained were compared with the results obtained without foam heat sink cases. In addition, the most heated elements within the cavity were identified and solution proposals were presented. In addition, the most heated elements within the cavity were identified and solution proposals were presented.     

A new high-performance CMOS fully differential second-generation current conveyor with application example of biquad filter realisation

In this article, a new complementary metal oxide semiconductor (CMOS) high-performance fully differential second-generation current conveyor (FDCCII) implementation is proposed. The presented FDCCII provides high-output impedance at terminals Z+ and Z?, good linearity and excellent output–input current gain accuracy. Also, the proposed FDCCII circuit operates at a supply voltage of ±1.3 V. The applications of the FDCCII to realise voltage-mode multifunction filters are given. Simulations are performed using TSMC CMOS 0.35-μm technology to verify theoretical results.     

New current–mode special function continuous-time active filters employing only OTAs and OPAMPs

This paper reports three current mode second order filters, each of which realizes a specific function without any external passive elements. These filters realize low-pass notch (LPN), high-pass notch (HPN) and all-pass (AP) functions. Two OPAMPs, a double output OTA and a single output OTA are employed for each circuit. The filter structures can be easily cascaded since they have high output impedances. This property is especially useful for achieving high-order filters using these LPN and HPN filters as building blocks. The presented theory is verified with macro models in SPICE simulations and, using the SPICE parameters of the layout technology, post layout simulations are carried out, with parasitics extracted from the layouts of the filter chips.     

On the Realization of MOS-Only Allpass Filters

The objective of this paper is to present a simple filter topology, which can be used to implement first- and second-order MOS-only allpass filters. The resulting filters realize the allpass functions without using any external passive components; hence these occupy very small chip area and are capable of operating at high frequencies. Cadence Spectre simulation and experimental results verifying the main advantages of the filters are provided.     

Modeling secrecy and deception in a multiple-period attacker–defender signaling game

In this paper, we apply game theory to model strategies of secrecy and deception in a multiple-period attacker–defender resource-allocation and signaling game with incomplete information. At each period, we allow one of the three possible types of defender signals—truthful disclosure, secrecy, and deception. We also allow two types of information updating—the attacker updates his knowledge about the defender type after observing the defender’s signals, and also after observing the result of a contest (if one occurs in any given time period). Our multiple-period model provides insights into the balance between capital and expense for defensive investments (and the effects of defender private information, such as defense effectiveness, target valuations, and costs), and also shows that defenders can achieve more cost-effective security through secrecy and deception (possibly lasting more than one period), in a multiple-period game.     

CCII-Based Grounded to Floating Immittance Converter and a Floating Inductance Simulator

A new circuit employing second-generation current conveyors (CCIIs), and unmatched resistors for converting a grounded immittance to the corresponding floating immittance with either positive or negative adjustable multiplier, is presented. Moreover, the proposed circuit can also realize a synthetic floating inductance employing a grounded capacitor depending on the passive element selection. Simulation results using 0.35 μ m TSMC CMOS technology parameters are given. Erkan Yuce was born in 1969 in Nigde, Turkey. He received the B.Sc. from Middle East Technical University and M.Sc. degrees from Pamukkale University in 1994 and 1998 respectively. He is a Ph.D. student at Bogazici University all in Electrical and Electronics Engineering. He is currently Research Assistant at the Electrical and Electronics Engineering Department of Bogazici University. His current research interests include analog circuits, active filters, synthetic inductors, and current-mode circuits. He is the author or co-author of about 10 papers published in scientific journals or conference proceedings. Oguzhan Cicekoglu was born in 1963 in Istanbul, Turkey. He received the B.Sc. and M.Sc. degrees from Bogazici University and the Ph.D. degree from Istanbul Technical University all in Electrical and Electronics Engineering in 1985, 1988 and 1996 respectively. He served as lecturer at the School of Advanced Vocational Studies Electronics Prog. of Bogazici University where he held various administrative positions between 1993 and 1999, and as part time lecturer at various institutions. He was with Biomedical Engineering Institute between 1999 and 2001. He is currently Associate Professor at the Electrical and Electronics Engineering Department of Bogazici University. His current research interests include analog circuits, active filters, analog signal processing applications and current-mode circuits. He is the author or co-author of about 150 papers published in scientific journals or conference proceedings. Oguzhan Cicekoglu is a member of the IEEE. Shahram Minaei received his B.Sc. degree in Electrical and Electronics Engineering from Iran University of Science and Technology in 1993. He received his M.Sc. and Ph.D. degrees in Electronics and Communication Engineering from Istanbul Technical University in 1997 and 2001, respectively. He is currently an Associate Professor at the Electronics and Communication Engineering Department of Dogus University in Istanbul, Turkey. He has more than 50 journal or conference papers in scientific review. He served as reviewer for a number of international journals and conferences. His current field of research concerns current-mode circuits and analog signal processing. Shahram Minaei is a member of the IEEE.     

ICCII-Based Voltage-Mode Filter with Single Input and Six Outputs Employing Grounded Capacitors

In this paper, a novel second-order voltage-mode filter with single input and six outputs employing inverting second-generation current conveyors (ICCIIs) is presented. This filter simultaneously realizes negative and positive gain lowpass, bandpass, and highpass filter responses, and does not require active and passive element matching. The new filter has low active and passive element sensitivities, and offers orthogonal control of the angular resonance frequency (ω_o) and quality factor (Q).     

A Versatile Active Circuit for Realising Floating Inductance, Capacitance, FDNR and Admittance Converter

An active circuit suitable for realizing floating inductance, capacitance, FDNR and admittance converter depending on the selection of passive elements of the circuit is presented. The proposed circuit employs only two dual output second-generation current conveyors (DO-CCIIs) and does not require passive element matching. The proposed network has a grounded capacitor for the floating inductance and capacitance simulation. Frequency performance of the circuit is tested using SPICE.     

First-order allpass sections-based current-mode universal filterusing ICCIIs

An inverting type current conveyor (ICCII) is presented and its usefulness in active filter synthesis illustrated by presenting a new current-mode universal filter using this element. The universal filter configuration based on the implementation of first-order allpass sections employs the absolute minimum number of passive and active components and hence leads to a filter circuit with very simple implementation