On the realization of high-order current-mode filter employing current controlled conveyors

In this paper, a general structure for realizing high-order current-mode analog filter responses with single-input and three-outputs is presented. The proposed circuit uses dual-output second-generation current controlled conveyors (DO-CCCIIs) and only grounded capacitors (Active-C structure), and can simultaneously realize low-pass, band-pass (if order is even number) and high-pass filter responses. The developed circuit does not require any component matching constraints thus it is suitable for fully integrated circuit (IC) technology. Simulations are performed for the fourth-order Butterworth filter to illustrate the frequency domain performance of the circuit.     

The failure mechanism of chromium as the interlayer to enhance the adhesion of nanocrystalline diamond coatings on cemented carbide

Chromium as an interlayer has been developed to enhance the adhesion of nanocrystalline diamond (NCD) coatings to cemented carbide cutting tool materials. This study showed that Cr did not play the expected role and that the NCD coating delaminated during the Rockwell C indentation test. A systematic study of the morphologies, composition, and phase components of the failed samples showed that although Cr prevented the outward diffusion of Co to the diamond interface, the chromium carbides formed during the NCD deposition contained microcracks, which provided a path for delamination in the presence of high tensile thermal stresses generated when cooling the coating to room temperature. This work provides additional criteria to choose an appropriate interlayer to enhance the adhesion of diamond coatings to cutting tool materials.     

The Effects of Non-Idealities and Current Limitations on the Simulated Inductances Employing Current Conveyors

Active devices such as current conveyors play an essential role on the performance of simulated inductances. The effects of second-generation current conveyor (CCII) non-idealities on the proposed and on the previously published inductances are investigated, in which lossless inductances are realized. CCIIs like all active devices have terminal current limitations that can not be exceeded. Thus, the values of the applied input current sources for the proposed and previously published inductances depending on the passive elements values and applied signal frequency impose restrictions on the input current of the inductor. Erkan Yuce was born in 1969 in Nigde, Turkey. He received the B.Sc. degree from Middle East Technical University and M.Sc. degree from Pamukkale University in 1994 and 1998 respectively, all in Electrical and Electronics Engineering. He is currently Research Assistant and a Ph.D. student at the Electrical and Electronics Engineering Department of Bogazici University. His current research interests include analog circuits, active filters, synthetic inductors, voltage-mode current-mode circuits. He is the author or co-author of about 4 papers published in scientific journals or conference proceedings Oguzhan Cicekogluwas 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.     

Spoilage and shelf life of sardines (Sardina pilchardus) packed in modified atmosphere

The effect of modified atmosphere packing (MAP) (O₂/CO₂/N₂, 5/35/60 (%) and O₂/CO₂/N₂, 5/70/25 (%)) on the quality of sardine stored in refrigerator was investigated in terms of sensory, chemical and microbiological analysis. Although chemical and microbiological analyses indicated that modified atmosphere packing prolonged the shelf life of sardine compared with that of air packing, sensory analysis showed that the extension of shelf life was (condition: O₂/CO₂/N₂, 5/70/25 (%)) 8 days and in air (condition: O₂/CO₂/ N₂, 5/35/60 (%)) 6 days. The results showed significant differences (p <0.05) between air and MAP storage conditions.     

Controlled release of chol-TEG-DNA from Nano- and micropatterned SU-8 surfaces by a spreading lipid film

We report the controlled release of immobilized cholesteryl-tetraethyleneglycol-DNA (chol-DNA) from micropatterned SU-8 surfaces by a spreading lipid film. The release of chol-DNA is rapid and on the order of the spreading rate of the lipid film beta = 1-3 microm2/s ( approximately 10(5) molecules of DNA per second). The lipid film serves as a poor solvent for the DNA adduct, which upon contact redistributes into the aqueous phase. Thus, the release of DNA is accompanied by a change in surface hydrophobicity. The method can be used for creating arbitrary concentration profiles of DNA in solution over time or to dynamically change surface properties on demand in, for example, micro- and nanofluidic devices. Examples of DNA release from spiral, comb, meander, and triangular as well as from nanoscale SU-8 lanes are shown.     

The evaluation of procedures for dyeing silk with buckthorn and walloon oak on the basis of colour changes and fastness characteristics

In this study, silk fabric samples were dyed according to various procedures with buckthorn (Rhamnus petiolaris Boiss) and walloon oak (Quercus ithaburensis Decaisne) extracts. Reversed‐phase high‐performance liquid chromatography with diode‐array detection was utilised for the identification of dyes present in the dyed silk fabrics and the plant extracts. The extraction of dyes was carried out with a hydrochloric acid/methanol/water (2:1:1; v/v/v) mixture. The colour coordinates of the silk fabrics were measured, and the rubbing, wash and light fastness properties of the dyed silk materials were determined and are discussed.     

Surface probing simulator for the evaluation of CMM probe radius correction software

Scanning coordinate metrology is largely based on recording the position of a spherical tip which is maintained in contact with the surface to be measured. The coordinate measuring machine (CMM) software converts these tip coordinates into coordinates of points on the measured surface, a process called probe radius correction. In order to investigate the probe radius correction accuracy of specific CMM software in scanning measurements, a surface probing simulator is developed. It calculates the coordinates of probe tip center points (virtual indicated measured points) as raw measurement data by numerically probing a known virtual surface. An iterative solution based on geometric criteria is used to achieve the necessary tangential contact conditions. Various sculptured surface profiles, probe radii, and scanning increments can then be simulated. These raw data are then fed to the CMM software where the probe radius correction is performed. The CMM results are then compared with the known surface to evaluate the probe radius correction accuracy of the CMM built-in algorithm. The simulator allows a rapid CMM software capability check for a variety of situations and may pinpoint shortfalls that may be avoided through alternative measurement procedures. It may also be used to motivate the development of new probe radius correction techniques and assist in their evaluation. Tests were conducted on a Zeiss and a Mitutoyo CMM to demonstrate the usefulness of the simulator.     

Comparative evaluation of different power management strategies of a stand-alone PV/Wind/PEMFC hybrid power system

This study presents different power management strategies of a stand-alone hybrid power system. The system consists of three power generation systems, photovoltaic (PV) panels, a wind turbine and a proton exchange membrane fuel cell (PEMFC). PV and wind turbine is the main supply for the system, and the fuel cell performs as a backup power source. Therefore, continuous energy supply needs energy storing devices. In this proposed hybrid system, gel batteries are used. The state of charge (SOC), charge-discharge currents are affecting the battery energy efficiency. In this study, the battery energy efficiency is evaluated with three different power management strategies. The control algorithm is using Matlab-Simulink®.