Coordinate Transformation-Free Observer-Based Adaptive Estimation of Distorted Single-Phase Grid Voltage Signal

© 2013 IEEE. This paper studies the phase and frequency estimation problem of single-phase grid voltage signal in the presence of DC offset and harmonics. For this purpose, a novel parameterized linear model of the grid voltage signal is considered where the unknown frequency of the grid is considered as the parameter. Based on the developed model, a linear observer (Luenberger type) is proposed. Then using Lyapunov stability theory, an estimator of the unknown grid frequency is developed. In order to deal with the grid harmonics, multiple parallel observers are then proposed. The proposed technique is inspired by other Luenberger observers already proposed in the literature. Those techniques use coordinate transformation that requires real-time matrix inverse calculation. The proposed technique avoids real-time matrix inversion by using a novel state-space model of the grid voltage signal. In comparison to similar other techniques available in the literature, no coordinate transformation is required. This significantly reduces the computational complexity w.r.t. similar other techniques. Comparative experimental results are provided with respect to two other recently proposed nonlinear techniques to show the dynamic performance improvement. Experimental results demonstrate the suitability of the proposed technique

A second‐order sliding mode control with active disturbance rejection for dynamic voltage restorers

This paper proposes an extended state observer (ESO)-based second-order sliding mode control (SMC) for dynamic voltage restorers (DVRs). Unlike the conventional first-order SMC and some second-order SMC (SOSMC) methods that suffer from chattering, the proposed control method can alleviate chattering and achieve finite-time convergence. Chattering suppression (i.e. eliminating discontinuities) is achieved via continuous control input which is also used to generate the pulse width modulation signals. However, while removing the discontinuities in the control input, the performance of the control method is degraded when it is subjected to disturbances. Therefore, an active disturbance rejection (ADR) based on an ESO is proposed to enhance the performance. In addition, an advanced single-phase phase-locked loop (PLL) using linear observer and quasi-type-1 PLL is also proposed. The effectiveness of the proposed method is verified through simulation and experimental results which are compared with the results of the existing SMC methods applied to DVR

Seismic resistance of traditional timber-frame hımış

Hımış structures have hardly ever found as extensive a role as other traditional timber housing, such as those originating from Japan or Central Europe, within the wide discourse on the seismic performance of timber-frame architecture that has gained significant momentum in the last few decades owing to advancing testing technologies. While the hımış construction technique was perhaps not born as a result of a conscious search for a seismically resistant building form, it was soon widely appreciated for its structural features advantageous under seismic loading - especially from the sixteenth century when it has become a well-established construction technique in part of the Balkans and in today’s Turkey. Despite widely available anecdotal information based on post-disaster studies regarding its performance under earthquakes, robust quantitative data on the seismic behaviour of these structures were practically non-existent until quite recently, and are still somewhat limited. However, we are now able to confirm that hımış constructions do have intrinsic qualities that are very beneficial under seismic action. This paper aims to make a brief review of the current state of our knowledge on structural performance of hımış buildings under earthquake loading, with specific emphasis on infill/cladding techniques, connection details and energy dissipation characteristics

Oral Papillomatosis in a Dog and its Therapy with Taurolidine

The efficacy of taurolidine on the treatment of oral papillomatosis in a 1-year-old Turkish Kangal dog was evaluated. Diagnosis of the papillomatosis was based on clinical signs, histopathological and immunohistochemical examinations. The dog received 45 mg/kg taurolidine intravenously every 3 days. Regression of papillomas started to be observed after the beginning of treatment, and complete resolution occurred after the fifth application

A comparison of intravenous sugammadex and neostigmine plus atropine reversal on time to consciousness during wake-up tests in spinal surgery

WOS: 000468923000004PubMed ID: 31089014Objective: The effect of sugammadex on consciousness is not yet fully understood. This prospective, randomized, double-blind, multicenter study was performed to compare the effects of intravenous (IV) sugammadex and neostigmine + atropine reversals on time-to-consciousness during intraoperative wake-up tests in patients undergoing spinal surgery. Subjects and Methods: A total of 66 American Society of Anesthesiologists IuII patients aged 10u25 years undergoing spinal surgery were recruited. In all patients, bispectral index (BIS), motor-evoked potential (MEP), somatosensory-evoked potentials (SSEP), and train-of-four (TOF) scores were monitored. Patients received the same total IV anesthesia protocol with a propofoluremifentanil mixture. Patients were randomly allocated into two groups. During wake-up test, when the TOF count reached 2 (T2), either sugammadex 2 mg.kg(1) in group S or neostigmine 0.04 mg.kg(1) + atropine 0.01 mg.kg(1) in group N were administered. BIS90, SSEP90, MEP90 was recorded when TOF ratio reached 90, whereas time-to-consciousness (Timecons) was recorded when the patient responded to verbal commands. Results: BIS90 (77.4 4.7, 74.8 3.7), SSEP90(36 9.9, 29.7 8.5), and MEP90 (465.3 34.8, 431.3 28.2) values were significantly greater in group S than in group N (P < 0.05 for each variables). Timecons was significantly shorter with sugammadex than with the neostigmine + atropine combination (P < 0.05). Conclusion: Using IV sugammadex 2 mg.kg(1) reversal provides faster responses to verbal commands than neostigmineuatropine combination during the intraoperative wake-up test in patients undergoing spinal surgery because the time to consciousness was significantly shorter. This difference was thought to be related with faster return of neuromuscular transmission because the TOF ratio was 0.9 well before return of consciousness in both groups

A comparison of intravenous sugammadex and neostigmine + atropine reversal on time to consciousness during wake-up tests in spinal surgery

PubMedID: 31089014Objective: The effect of sugammadex on consciousness is not yet fully understood. This prospective, randomized, double-blind, multicenter study was performed to compare the effects of intravenous (IV) sugammadex and neostigmine + atropine reversals on time-to-consciousness during intraoperative wake-up tests in patients undergoing spinal surgery. Subjects and Methods: A total of 66 American Society of Anesthesiologists I-II patients aged 10-25 years undergoing spinal surgery were recruited. In all patients, bispectral index (BIS), motor-evoked potential (MEP), somatosensory-evoked potentials (SSEP), and train-of-four (TOF) scores were monitored. Patients received the same total IV anesthesia protocol with a propofol-remifentanil mixture. Patients were randomly allocated into two groups. During wake-up test, when the TOF count reached 2 (T2), either sugammadex 2 mg.kg-1 in group S or neostigmine 0.04 mg.kg-1 + atropine 0.01 mg.kg-1 in group N were administered. BIS90, SSEP90, MEP90 was recorded when TOF ratio reached 90, whereas time-to-consciousness (Timecons) was recorded when the patient responded to verbal commands. Results: BIS90 (77.4 ± 4.7, 74.8 ± 3.7), SSEP90(36 ± 9.9, 29.7 ± 8.5), and MEP90 (465.3 ± 34.8, 431.3 ± 28.2) values were significantly greater in group S than in group N (P &lt; 0.05 for each variables). Timecons was significantly shorter with sugammadex than with the neostigmine + atropine combination (P &lt; 0.05). Conclusion: Using IV sugammadex 2 mg.kg-1 reversal provides faster responses to verbal commands than neostigmine-atropine combination during the intraoperative wake-up test in patients undergoing spinal surgery because the time to consciousness was significantly shorter. This difference was thought to be related with faster return of neuromuscular transmission because the TOF ratio was &gt;0.9 well before return of consciousness in both groups. © 2019 Nigerian Journal of Clinical Practice

Comparison of the effects of epidural levobupivacaine with tramadol or morphine addition on postoperative analgesia following major abdominal surgery [Majör abdominal cerrahilerde postoperatif analjezi İçin epidural levobupivakaine İlave edilen tramadol İle morfin’in etkilerinin Karşılaştırılması]

Objective: The study was designed to compare the postoperative analgesic efficacy of epidural tramadol or epidural morphine as adjuvant to levobupivacaine in major abdominal surgery. Methods: Patients in ASA I-II group aged between 18 and 65 years were included in study. Epidural catheter was introduced. Patients were randomised into three groups to receive levobupivacaine (Group L), levobupivacaine+morphine (Group LM) and levobupivacaine+tramadol (Group LT). General anaesthesia was administered to all patients. The solution intended for Group L contained 25 mg 0.5% levobupivacaine+15 mL saline, that for Group LM contained 25 mg 0.5% levobupivacaine+14.5 mL salin+100 µg morphine and that for Group LT contained 25 mg 0.5% levobupivacaine+13 mL salin+100 mg tramadol, which was administered via epidural catheter as loading dose 30 min before the end of the operation. Patient-controlled analgesia device was connected to the epidural catheter for evaluating postoperative analgesia. Bolus dose was adjusted to 12 mg levobupivacaine in Group L, 12 mg levobupivacaine +1.2 mg morphine in Group LM and 12 mg levobupivacaine+12 mg tramadol in Group LT. Lock-out period was adjusted to 15 min in three groups. Quality of analgesia was evaluated using Visual Analogue Scale; administered and demand doses of levobupivacaine, morphine and tramadol were compared at 30 min, 1, 2, 6, 12 and 24 h postoperatively. Results: Visual Analogue Scale scores were significantly higher in Group L than Groups LM and LT. Nausea and vomiting observed in Group L were lesser than those in Groups LM and LT. Conclusion: Continuous epidural analgesia using levobupivacaine combined with morphine or tramadol is an effective method for managing postoperative analgesia in major abdominal surgery. © 2019 by Turkish Anaesthesiology and Intensive Care Society