Application of experimental non-linear control based on generic algorithm to a polymerization reactor

Gülay Özkan,Öznur Tekin,Hale Hapoglu 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.5

The dynamics of free radical polymerization of styrene and on-line control of temperature in a cooling jacketed batch polymerization reactor is investigated. The benzoyl peroxide initiator is introduced into the reactor once at the beginning of the reaction to obtain the desired monomer conversion and the desired average chain length in a minimum reaction time. The optimal constant set temperature, which is generally realized in industrial applications, and the set profile are used as two different optimal operating conditions. The temperature control of the polymerization reactor is achieved experimentally and theoretically. The control of nonlinear systems has progressed considerably, and various nonlinear process model based control techniques have appeared in the literature. The problem is how to tune the controller in order to obtain comparable closed loop responses. Generic model control (GMC) is applied and the performance of the control results are compared with the previously published control results.

Effects of cholesterol and Lactobacillus acidophilus on testicular function

Gülay Çiftci,Elif Tuna 대한생식의학회 2021 Clinical and Experimental Reproductive Medicine Vol.48 No.3

Objective: In this study, the effects of Lactobacillus acidophilus on testosterone (TES), follicle-stimulating hormone (FSH), luteinizing hormone (LH), androgen-binding protein (ABP), factor-associated apoptosis (FAS), and total cholesterol (TC), as well as histopathological changes, were investigated in male rats fed a high-cholesterol diet. Methods: The study included three groups. The control (C) group was fed standard-diet for 8 weeks. The hypercholesterolemia (HC) group was fed a 2% cholesterol-diet for 8 weeks. The therapeutic group (HCL) was fed a 2% cholesterol-diet for 8 weeks and administered L. acidophilus for the last 4 weeks. FSH, TES, and FAS levels in testicular tissue were determined using an enzyme-linked immunosorbent assay (ELISA), while another sample was examined histopathologically. LH and ABP levels were determined using ELISA, and serum TC levels were assessed via an autoanalyzer. Results: In the HC group, the TC levels were significantly higher and the LH levels were lower (p<0.05) than in the C group. The ABP levels were lower (p>0.05). In the HCL group, the LH and ABP levels were higher (p>0.05) and the TC level significantly lower (p<0.05) than in the HC group. The TES and FSH levels were lower, and the FAS levels were higher, in the HC than in the C group (p<0.05). In the HCL group, levels of all 3 resembled control levels. Histologically, in the testicular tissue of the HC group, the cells in the tubular wall exhibited atrophy, vacuolization, and reduced wall structure integrity. However, in the HCL group, these deteriorations were largely reversed.Conclusion: Supplementary dietary administration of an L. acidophilus to hypercholesterolemic male rats positively impacted testicular tissue and male fertility hormone levels.

Investigation of the performance of a thermoelectric generator system utilizing the thermal energy of air compressed in a compressor

Gürcan Ali,Yakar Gülay 한국물리학회 2022 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.80 No.6

The present study includes a numerical analysis on the electrical power output of a thermoelectric generator system placed between a compressor and the intercooler of a turbocharged tractor. Although current literature already includes reports on thermal energy of exhaust gases used by thermoelectric generators in automobiles, this study is oriented on the utility of the thermal energy of the compressed outlet air from the compressor by the thermoelectric generators. This is the uniquness of the present study. Numerical results showed that the highest and the lowest performances occurred at outdoor temperatures of 268 K and 303 K, respectively. From a single thermoelectric module, while a 1.23 W power output was obtained at outdoor temperature of 268 K, a 0.7 W power output was obtained at 303 K. The thermoelectric generator system used in this study consisted of 28 thermoelectric generator modules. The power output generated by this system can be used for any electrically powered devices on a tractor, such as a tractor refrigerator with a thermoelectric cooler whose power requirement can be easily satisfied by using the thermoelectric generator system. In a turbocharged tractor with a thermoelectric generator, the temperature of the air entering into the intercooler for a single thermoelectric generator module was decreased by 1.6% at an outdoor temperature of 268 K in comparison with the one without the thermoelectric generator.

Update on polycystic ovary syndrome

Gülay Çiftci 대한생식의학회 2021 Clinical and Experimental Reproductive Medicine Vol.48 No.3

Polycystic ovary syndrome (PCOS) is a common disorder in reproductive-age women. In 2018, an international evidence-based guideline announced recommendations spanning a wide range of issues on the assessment and management of PCOS. From the 166 recommendations, the present study reviews those that are of particular clinical relevance for daily practice and introduces other relevant studies that have been published since the global guideline. The 2018 guideline increased the antral follicle count cutoff for the diagnosis of PCOS from 12 to 20 when using a high-frequency probe. Hirsutism was defined as having a score of ≥4–6 based on a lower percentile of 85%–90% or cluster analysis, which was lower than the traditionally used 95th percentile-based cutoff. The diagnosis of PCOS in adolescents is challenging, and irregular menstruation was defined carefully according to years from menarche. The use of ultrasonography for the diagnosis of PCOS was restricted to those 8 years after menarche. As medication for non-fertility indications, combined oral contraceptives are the first-line drug. Metformin, in addition to lifestyle modifications, should be considered for adult patients with a body mass index ≥25 kg/m2 for the management of weight and metabolic outcomes. An aromatase inhibitor is the recommended first-line medication for ovulation induction, a subsequent individual patient data meta-analysis also reported the same conclusion. Whether the new global guideline will be fully adopted by many specialists and change clinical practice is open to question. Further studies are needed to better understand and manage PCOS patients well.

Investigation of the relationship between students’ academic achievement and schools’ leadership capacity: An analysis of lower secondary schools in Turkey

Gülay Aslan 한국교육개발원 2020 KEDI Journal of Educational Policy Vol.17 No.1

The purpose of this study was to determine lower secondary school students’ academic achievement based on the leadership capacity of schools. The relational survey model was applied using a Turkish adaptation of the Leadership Capacity School Survey with a sample of 1836 students and 525 faculty and staff at 17 schools. The Study found that the leadership capacity of the schools was above average. Results of the Hierarchical Linear Modeling analysis revealed a significant difference among the schools in terms of students' achievements of graduation and transition to upper secondary schools. Moreover, the research revealed that schools’ leadership capacity predicted students’ achievements in graduation and transition to upper secondary schools. The implications of the study were that the leadership competency of educators should be improved through pre-service training at faculties of education for teacher candidates and in-service training carried out by the Ministry of National Education for teachers.

Evaluation of mesial root canal configuration of mandibular first molars using micro-computed tomography

Altan Şallı Gülay,Egil Edibe 대한영상치의학회 2021 Imaging Science in Dentistry Vol.51 No.4

Purpose: The aim of this study was to evaluate the root canal morphology of mesial roots of mandibular first molars. Materials and Methods: Forty extracted mandibular first molars were used in this study. The morphological examination of root canals was conducted in accordance with the Vertucci classification using micro-computed tomography (micro-CT). Any aberrant root canal configurations not included in the Vertucci classification were recorded, and their frequency was established using descriptive statistics. Intra-observer reliability was assessed using the Wilcoxon signed-rank test, while inter-observer reliability was assessed using the Cohen kappa test. Significance was evaluated at the P<0.05 level. Results: The mesial roots of mandibular first molars had canal configurations of type I (15%), type II (7.5%), type III (25%), type IV (10%), type V (2.5%), type VI (7.5%), and type VII (7.5%). The images showed 10 (25%) additional configuration types that were not included in the Vertucci classification. These types were 1-3-2-3, 1-2- 3-2-3, 2-3-1, 2-3, 1-2-3-1, 2-1-2-3, 3-2-1, 1-2-3-1, 2-3-2-3, and 1-2-1-2-1. The intra-observer differences were not statistically significant (P>0.05) and the kappa value for inter-observer agreement was found to be 0.957. Conclusion: Frequent variations were detected in mesial roots of mandibular first molars. Clinicians should take into consideration the complex structure of the root canal morphology before commencing root canal treatment procedures to prevent iatrogenic complications. Micro-CT was a highly suitable method to provide accurate 3-dimensional visualizations of root canal morphology.

Comparison of the effects of on-pump and off-pump coronary artery bypass surgery on cerebral oxygen saturation using near-infrared spectroscopy

Guray Demir,Zafer Çukurova,Gülay Eren,Oya Hergünsel 대한마취통증의학회 2014 Korean Journal of Anesthesiology Vol.67 No.6

Background: Central nervous system complications are the most clinically important of those affecting mortality in patientsundergoing coronary artery surgery. Newly developed sophisticated techniques and surgical interventions obviatingthe need for cardiopulmonary pumps have facilitated avoidance of these complications. In this study, we comparedthe impact of on-pump and off-pump coronary artery bypass surgery on cerebral oxygenation using near-infrared spectroscopy. Methods: This study included 40 patients with no comorbidities who were scheduled for on-pump (n = 20) and offpump(n = 20) cardiac surgery. Preoperative and postoperative Standardized Mini-Mental State Examination (SMMSE)scores, perioperative mean arterial blood pressure (MAP), hematocrit (Hct), peripheral oxygen saturation (SpO2), regionalcerebral oximetry values (rSO2), body temperature, and partial pressure of carbon dioxide (PCO2) were recorded,for all patients. Intergroup and intragroup comparisons were then performed. Results: The mean operative time was longer in the on-pump group. SMMSE scores were similar and relevant postoperativevalues were lower in both groups. Perioperative MAP, PCO2, and SpO2 were similar in both groups. SpO2 and PCO2did not differ from baseline levels in either group, while the postextubation MAP at 2 h postoperatively remained low. Hct levels decreased during the perioperative and postoperative periods, while the body temperature declined perioperativelyand to a greater degree in the on-pump group. The intraoperative and postoperative rSO2 decreased in both groups. In the on-pump group, the decrease in rSO2 was more prominent during the interval between the start and closure of thesternotomy. Conclusions: Physiological alterations that occur during coronary artery surgery affect cerebral oxygenation duringand after the operation irrespective of the application of a cardiopulmonary pump. Cerebral oxygenation decreases to agreater extent during on-pump surgery; however, probably because of the neuroprotective effects of hypothermia, thepostoperative changes resemble those of off-pump surgery.

Silica Aerogel Application to Polyester Fabric for Outdoor Clothing

Pelin Altay,Raziye Atakan,Gülay Özcan 한국섬유공학회 2021 Fibers and polymers Vol.22 No.4

Most producers want to have a cheap, one-step system that will successfully apply multi-finishing operationswithout affecting any of the desired textile properties. Silica aerogel, used for isolation purposes in different areas such asconstruction, has been used in textile finishing in this study. 100 % polyester fabrics, which are widely used in outerwear,were impregnated with silica aerogel paste and binder at lower temperature and time than that applied for conventionalcoating method, providing decreased energy consumption. The samples were tested for wettability, soil release andhydrophobicity both before and after repeated laundering. Burst strength tests were also performed to investigate strengthproperties of the fabrics. The presence of silica groups on the treated fabrics was confirmed by FTIR spectra and thermalcharacteristics of the samples were evaluated by using differential scanning calorimeter (DSC). The results showed thataerogel impregnated fabrics provide superhydrophobic properties with a contact angle of around 170 o and improved soilrelease properties even at very low add-ons. It was also found that the silica aerogel treatment has no adverse effect on thefabric appearance or strength properties.

The Vasodilator Effect of a Cream Containing 10% Menthol and 15% Methyl Salicylate on Random- Pattern Skin Flaps in Rats

Utku Can Dölen,Nezih Sungur,Gökhan Koca,Onur Ertunç,Ayşe Tülay Bağcı Bosi,Uğur Koçer,Meliha Korkmaz 대한성형외과학회 2015 Archives of Plastic Surgery Vol.42 No.6

Background It is still difficult to prevent partial or full-thickness flap necrosis. In this study, the effects of a cream containing menthol and methyl salicylate on the viability of randompattern skin flaps were studied. Methods Forty female Sprague-Dawley rats were divided into two equal groups. Caudally based dorsal random-pattern skin flaps were elevated, including the panniculus carnosus. In the study group, 1.5 mL of a cream containing menthol and methyl salicylate was applied to the skin of the flap, and saline solution (0.9%) was used in the control group. Upon completion of the experiment, flap necrosis was analyzed with imaging software and radionuclide scintigraphy. Histopathological measurements were made of the percentage of viable flaps, the number of vessels, and the width of the panniculus carnosus muscle. Results According to the photographic analysis, the mean viable flap surface area in the study group was larger than that in the control group (P=0.004). According to the scintigrams, no change in radioactivity uptake was seen in the study group (P>0.05). However, a significant decrease was observed in the control group (P=0.006). No statistically significant differences were observed between the groups in terms of the percentage of viable flaps, the number of vessels, or the width of the panniculus carnosus muscle (P>0.05). Conclusions Based on these results, it is certain that the cream did not reduce the viability of the flaps. Due to its vasodilatory effect, it can be used as a component of the dressing in reconstructive operations where skin perfusion is compromised.

Does the Use of Rocuronium-Sugammadex Instead of Succinylcholine in Electroconvulsive Therapy Affect Seizure Duration?

Oflezer Ceyhan,Atay Özge,Kaşdoğan Zümrüt Ela,Özakay Gülay,İpekçioğlu Derya,Bahadır Hakan 대한신경정신의학회 2022 PSYCHIATRY INVESTIGATION Vol.19 No.10

Objective We compared retrospectively the seizure variables of electroconvulsive therapy (ECT) patients after administration of rocuronium-sugammadex or succinylcholine as a muscle relaxant with propofol anesthesia.Methods The sample comprised 134 ECT patients. The mean age was 33.6±10.48 years. Anesthesia induction was provided with propofol one mg kg-intravenously (IV) followed by succinylcholine 0.5 mg kg^-1 IV (n=68) (Group S) or rocuronium 0.3 mg kg^-1 IV (n=66) (Group R). For patients who were given rocuronium, reversal of the residual neuromuscular block was accomplished with sugammadex (1.5 mg kg^-1 IV). First session seizure variables were compared between the two groups. We also presented the clinical outcome with Clinical Global Impression-Improvement (CGI-I) and overall adverse effects.Results EEG seizure durations in Group R (55.09±36.11 s) and Group S (47.00±26.33 s) were comparable and were not significantly different (p=0.432). The clinical efficacy of ECT measured by CGI-I in both groups was comparable (p=0.075). There were no major complications or death during or after ECT.Conclusion The results of this study show that the use of rocuronium-sugammadex as a neuromuscular blocker instead of succinylcholine during ECT with propofol anesthesia produces similar results in terms of seizure variables and clinical outcomes.