Zonguldak Bülent Ecevit University Institutional Repository
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Fluorescent Lamp Modelling and Electronic Ballast Design by the Support of Root Placement
No full textA Parametric Study on Determining the Corrosion Initiation and Propagation Times of Reinforced Concrete Structures Using Different Methods
No full textReinforced concrete structures deteriorate over time when exposed to environmental effects throughout their service life, resulting in a loss of structural performance and ultimately a reduction in service life. One of the most critical deterioration mechanisms in this process is the corrosion of the reinforcement steel. The initiation and propagation of corrosion adversely affect the load-bearing capacity, bond strength, and overall structural behavior of reinforced concrete elements, thereby threatening the structural safety. Therefore, understanding the corrosion process and accurately predicting the service life of reinforced concrete structures is critical to ensuring their long-term durability. This study comprehensively examines the effects of chloride-induced rebar corrosion on the service life of reinforced concrete structures. Various mathematical models used to predict corrosion initiation and propagation times are analyzed in detail. These models provide a scientific basis for understanding the effects of environmental conditions and structural properties on the corrosion process and estimating how these effects affect the service life. In particular, the study investigates the effect of parameters such as concrete cover thickness, rebar diameter, crack presence, corrosion rate, and environmental conditions on the corrosion process, all of which also affect structural performance. Cracks in reinforced concrete elements shorten the corrosion initiation period depending on their thickness. Considering that the presence of cracks also changes the structural behavior, it is recommended to use the Kwon model, which takes the presence of cracks into account, in the service life calculations. The presence of cracks is ineffective in the corrosion propagation period, and it is recommended to use the Morinaga model for this period. For reinforced concrete elements exposed to aggressive environments, increasing the thickness of the concrete cover and the diameter of the reinforcement has been shown to increase the service life. Columns with larger diameter reinforcement showed a longer service life than beams with smaller diameter reinforcement. Therefore, evaluating each element separately in service life calculations will ensure that a safer approach is taken. In conclusion, this study serves as a valuable resource for developing design strategies to improve the long-term durability of reinforced concrete structures and to minimize the adverse effects of corrosion on structural performance. It provides design and field engineers with guidance to make more accurate service life assessments and implement effective decisions to improve structural performance.</jats:p
Examination of prospective teachers’ views, attitudes, and practices towards the history and philosophy of science course
No full textThe history and philosophy of science course is among the very important courses for prospective teachers in terms of understanding the development of science, evaluating its social and cultural context, developing scientific thinking skills, and better understanding and teaching scientific knowledge. Studies on this subject are important in terms of teaching planning and development. This research aimed to examine prospective teachers’ opinions, attitudes and practices towards the history and philosophy of science course. The study group, conducted within the scope of a special case study, consists of 54 prospective teachers studying at a state university in different programs in the 2020-2021 academic year. An opinion form prepared by taking expert opinions, the history of science attitude scale and lesson plans prepared by prospective teachers were used as data collection tools. Additionally, semi-structured interviews were conducted and recorded with six prospective teachers. The data obtained from the opinion form, interviews and lesson plans were analyzed qualitatively and codes, categories and themes were created. The findings obtained were interpreted and supported by direct quotations. The data obtained from the attitude scale was analyzed with the SPSS program. The findings revealed that the attitudes towards the history and philosophy of science course were generally positive, the course content was sufficient, and the prospective teachers found the course fun, interesting, intriguing, and very useful in terms of questioning and developing different perspectives. In line with the results obtained, suggestions were made to educators and researchers.</jats:p
Libri Carolini Bağlamında Şarlman Dönemi İkona Algısı
No full textSekizinci asırda Bizans, Batı’nın aksine çok yoğun bir şekilde ikona tartışmalarına sahne olmuştur. 754 yılında Hieria konsili ile birlikte ikonaların ibadetlerde kullanılmasının kesin olarak yasaklanmasının yarattığı şok, 787 yılında ikonaların kutsallığını tanıyan II. İznik konsili ile giderilmeye çalışılmışsa da bu konu arada bir canlanan ama sürekli devam eden bir çatışma yaratmıştır. Batı’da ise Doğu’daki kadar önemli bir yer işgal etmeyen ikona konusu II. İznik Konsili’nin kararlarının Şarlman’a ulaşmasıyla gündeme gelmiştir. Şarlman’ın önemli ilahiyatçılarının bu konuya eğilmesi ve onlardan biri olan Theodulf’un yoğun çabaları neticesinde Libri Carolini olarak bilinen çalışma ortaya çıkmıştır. Libri Carolini, II. İznik Konsili’nin ikona tapımına yönelik iddialara cevaben oluşturulmuş polemiksel bir çalışma olmakla birlikte önceki konsilin ikona karşıtı tutumunu da eleştirmekten kaçınmamıştır. Bu bakımdan Şarlman’ın ağzından yazılan ve dört kitaptan oluşan bu kapsamlı çalışma Batı’nın yani Karolenj dünyasının ikonalara yönelik ılımlı yaklaşımını derinlikli olarak ortaya koyan bir çalışmadır. Makale, çalışmanın ortaya çıkış süreci ve içeriğine dair bazı detaylar üzerinden Batı’nın ikona algısını ortaya koymayı amaçlamakla birlikte, Doğu-Batı, İmparator-Kilise ilişkilerine ışık tutmayı ümit etmektedir.</jats:p
Evaluation of parotid and submandibular salivary glands with ultrasonography in diabetic patients
No full textThe main symptom of diabetes mellitus (DM) is hyperglycaemia, and patients with DM often have microvascular complications, such as retinopathy, neuropathy, and nephropathy; macrovascular complications, such as coronary heart disease, peripheral arterial disease and cerebrovascular disease; and oral complications, such as xerostomia, hyposalivation and periodontal disease. The main aim of this study was to evaluate the submandibular and parotid glands in type 2 DM patients and healthy individuals and to determine the changes in the salivary glands caused by diabetes.In this study, the salivary glands of 100 patients (50 individuals with type 2 DM and 50 healthy individuals) were evaluated by ultrasonography (US). Echogenicity, parenchymal homogeneity, hypoechogenic and hyperechogenic areas, margin characteristics, and vascularity of the glands were analysed. The anteroposterior, superoinferior, and mediolateral lengths and volumes of the submandibular glands were measured.Statistically significant differences in submandibular gland echogenicity, parotid gland vascularity, and hyperechogenic reflections of the parotid glands were observed between the groups (p < 0.05). In addition, the volume and dimensions of the submandibular glands were significantly greater in the type 2 DM group.DM leads to changes in the salivary glands. US, which has many advantages for salivary gland imaging, is a highly effective method for investigating these changes in individuals with diabetes.US, which is well tolerated by patients and does not involve ionizing radiation, can be used for long-term monitoring of the effects of diabetes mellitus on the salivary glands
Cognitive disengagement syndrome: The same as or different from attention-deficit hyperactivity disorder? An examination based on biochemical parameters
No full textThe aim of this study was to determine whether there are differences in the biochemical blood parameters between individuals with Cognitive Disengagement Syndrome (CDS) and Attention Deficit Hyperactivity Disorder (ADHD), and to investigate the relationship between vitamin levels and these disorders, as well as their impact on symptom severity.The study included 35 patients with ADHD, 35 patients with both ADHD and CDS, and 35 healthy control subjects who presented to the child and adolescent psychiatry outpatient clinic between January 2022 and 2023, matched for age and gender. Children aged 7-15 were included in the study. Participants were administered a sociodemographic data form, DSM-IV Based Screening and Assesment Scale for Disruptive Behavior Disorders- Parent form (DBSAS-DBD) and the Barkley Child Attention Scale (BCAS). Hemogram parameters, iron, ferritin, Thyroid Stimulating Hormone (TSH), T3, T4, and vitamin levels (B12, folic acid, vitamin D) were analyzed for all participants.Of the participants, 78 (74.3%) were male, and 27 (25.7%) were female. In the analysis, Vitamin B12 and D levels were found to be significantly lower in the ADHD + CDS group compared to both the ADHD group and the control group (p = 0.04; p = 0.03; p = 0.009 p = 0.004 respectively). Hemoglobin levels did not significantly differ between the ADHD + CDS group and the ADHD group, but were significantly higher in the ADHD + CDS group compared to the control group (p = 0.004). Ferritin levels were significantly lower in both the ADHD + CDS group and the ADHD group (p < 0.001; p < 0.001, respectively).The significant decrease in vitamin B12 and vitamin D in the CDS + ADHD group may be related to daytime sleepiness and slow cognitive processes in the CDS clinic. Screening for nutritional deficiencies in individuals with CDS may be beneficial for clinical management, and identifying differences in blood parameters of CDS from ADHD will contribute to a better understanding of this clinical condition. This is an exploratory study with a rather small sample size, in which many outcomes were examined. Further studies with larger and more diverse samples will provide a more comprehensive understanding of the biochemical foundations of these two conditions
The determinants and the inverses of the --Toeplitz and the --Toeplitz matrices
No full textAbstract In this paper, we define two families of matrices and provide explicit forms for their determinants and inverses. The results are general and the particular cases of some Loeplitz and Foeplitz matrices considered in the recent literature can be easily derived.</jats:p
HOW DID THE MEDIA FRAME COP29?: TURKISH MAINSTREAM MEDIA & FOREIGN PRESS IN TURKISH
No full textThis study examines how the Turkish mainstream media and Turkish-language foreign press frame Turkey's environmental policies in the context of the COP29 summit and how they address the differences in this process. The research reveals significant ideological differences in the news frames related to COP29 between the two media groups. From the Turkish mainstream media, Sabah and Hürriyet generally present the government officials' environmental policies and participation in COP29 in a positive light, while Cumhuriyet, Sözcü, and the Turkish foreign press adopt a more critical stance. Hürriyet and Sabah tend to link environmental policies with economic development and national success, whereas Cumhuriyet, Sözcü, and the foreign press highlight the insufficiency of these policies and their misalignment with global goals. The study also examines the differences in the sources used by both media groups. In Sabah and Hürriyet, official sources such as government representatives and the Ministry of Environment are predominantly featured, while in the foreign press, Cumhuriyet, and Sözcü, critical sources like independent experts and environmental organizations are more prominently used. Ultimately, this study reveals that the coverage of the COP29 process differs significantly between government-aligned mainstream media and opposition-leaning mainstream media as well as the Turkish foreign press, with each group employing distinct frames in their reporting.</jats:p