Time Delay Feedback Control based Chaos Stabilization in Current Mode Controlled DC Drive System

This paper focuses on delay feedback control scheme to eliminate chaos in a current mode controlled DC drive system. The delay feedback method is applied for the current mode DC drive system which exhibits chaotic behavior for some parameter variations to control the chaos in DC drive system. Firstly, the change of system behavior from normal to chaotic operation is shown by changing some parameters. To control the chaos in current mode DC drive system, the controller designed based on time delay feedback control method is applied to DC drive system which works in chaotic regime. It is showed that the behavior of system changes from chaotic regimes to normal operation by applying the time delay feedback control

Portable automated radio-frequency scanner for non-destructive testing of carbon-fibre-reinforced polymer composites

A portable automated scanner for non-destructive testing of carbon-fibre-reinforced polymer (CFRP) composites has been developed. Measurement head has been equipped with an array of newly developed radio-frequency (RF) inductive sensors mounted on a flexible arm, which allows the measurement of curved CFRP samples. The scanner is also equipped with vacuum sucks providing mechanical stability. RF sensors operate in a frequency range spanning from 10 up to 300 MHz, where the largest sensitivity to defects buried below the front CFRP surface is expected. Unlike to ultrasonic testing, which will be used for reference, the proposed technique does not require additional couplants. Moreover, negligible cost and high repeatability of inductive sensors allows developing large scanning arrays, thus, substantially speeding up the measurements of large surfaces. The objective will be to present the results of an extensive measurement campaign undertaken for both planar and curved large CFRP samples, pointing out major achievements and potential challenges that still have to be addressed

Second record of Ramularia hypericicola - collected in Turkey on a new host

WOS: 000302997300041Ramularia hypericicola, a rare anamorphic Mycosphaerella species, is reported and illustrated from Turkey on Hypericum calycinum. The Turkish collection represents the second report of this fungus, known hitherto only from the type locality

Analysis of Enterococcus faecalis in samples from Turkish patients with primary endodontic infections and failed endodontic treatment by real-time PCR SYBR green method

OBJECTIVE: The aims of this study were to investigate the presence of Enterococcus faecalis in primary endodontic infections and failed endodontic treatments using real-time PCR and to determine the statistical importance of the presence of E. faecalis in a Turkish population with endodontic infections. MATERIAL AND METHODS: E. faecalis was investigated from 79 microbial samples collected from patients who were treated at the Endodontic Clinic of the Dental School of Atatürk University (Erzurum, Turkey). Microbial samples were taken from 43 patients (Group 1) with failed endodontic treatments and 36 patients (Group 2) with chronic apical periodontitis (primary endodontic infections). DNA was extracted from the samples by using a QIAamp® DNA mini-kit and analyzed with real-time PCR SYBR Green. RESULTS: E. faecalis was detected in 41 out of 79 patients, suggesting that it exists in not less than 61% of all endodontic infections when the proportion test (z= -1.645