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New Studies on Chalcopyrite Thin Film Solar Cells: Silver Alloying
No full textBu çalışmada, kalkopirit güneş hücreleri ile ilgili genel bilgiler verildikten sonra farklı üretim yöntemleri, güneş hücresi tabakalarına uygulanan geliştirme yöntemleri ve dünya genelinde yapılan araştırmaların durumu incelenmiştir. Kalkopirit güneş hücrelerinin %26 verim ile farklı tipteki güneş hücreleri ile yarışabilir pozisyonda olduğu gösterilmiştir. Geleneksel kalkopirit yapının son yıllarda yerini gümüş alaşımlanmış kalkopirit yapıya bıraktığı tespit edilmiştir. Gümüş alaşımlama araştırmaları gümüş alaşımlanmış kalkopirit yapının geleneksel kalkopirit yapıya kıyasla aynı üretim sıcaklıklarında daha iyi tane büyümesi sergilediğini göstermiştir. Bu durum da kristal kalitesinin artmasını sağlamıştır. Ayrıca, gümüş alaşımlama ile yasak bant aralığının genişletilebilmesi çok katlı tandem güneş hücresi çalışmalarına katkıda bulunmuştur. Geniş yasak bant aralığı çalışmalarına yapmış olduğu en büyük katkı kalkopirit yapıdaki galyumun dağılımının kontrol edilebilmesini sağlamasıdır. Bununla birlikte, gümüş alaşımlama rekombinasyonu azaltıp açık devre voltajını artırdığı için daha iyi verim sonuçları alınmıştır. Bu teknoloji ile şeffaf ve esnek güneş hücresi tasarlanabiliyor olması da çok önemlidir. Kalkopirit güneş hücreleri ile ilgili çalışmaların geleceğinin gümüş alaşımlama ile şekilleneceği öngörülmektedir. Hem esnek hem de şeffaf güneş hücrelerinin giyilebilir güneş hücresi, bina uygulamaları ve tarım arazilerinde kullanılabilen agrivoltaik gibi alanlarda kullanılabileceği gerçeği konunun önemini artırmaktadır.In this study, after giving general information about chalcopyrite solar cells, different production methods, development methods applied to solar cell layers and the status of research conducted around the world are examined. It has been shown that chalcopyrite solar cells can compete with different types of solar cells with an efficiency of 26%. It has been determined that the traditional chalcopyrite structure has been replaced by silver alloyed chalcopyrite structure in recent years. Silver alloying research has shown that the silver alloyed chalcopyrite structure exhibits better grain growth at the same production temperatures compared to the traditional chalcopyrite structure. This has enabled the crystal quality to increase. Additionally, widening the bandgap by silver alloying has contributed to multilayer tandem solar cell studies. The biggest contribution of silver alloying to wide bandgap studies is the ability to control the distribution of gallium in the chalcopyrite structure. Moreover, better efficiency results were obtained because silver alloying reduced recombination and increased the open circuit voltage. It is also very important that transparent and flexible solar cells can be designed with this technology. It is predicted that the future of studies on chalcopyrite solar cells will be shaped by silver alloying. The fact that both flexible and transparent solar cells can be used in areas such as wearable solar cells, building applications and agrivoltaics that can be used in agricultural lands increases the importance of the subject
Determination of the Location of the sheet pile wall Placed within the Impermeable Dam Base Using the Finite Difference Method
No full textZemindeki su akımlarında, zeminin çıkış bölgesinde akım yönü yerçekimine zıt yönde ise kaynama (boiling) olayı gerçekleşebilir. Kaynama olayını önlemek için akım yolu uzunluğu arttırılır veya kaynama riskinin bulunduğu bölgede ağırlık filtresi kullanılır. Akım yolu uzunluğunun arttırılması geçirimsiz barajlarda barajın memba (giriş) bölümünde geçirimsiz bir tabaka oluşturulması veya baraj altına geçirimsiz palplanş perdesi yapmakla mümkündür. Palplanş Perdesinin geçirimsiz baraj altında inşaası masraflı ve zordur. Bu çalışmada baraj duvarı altındaki Palplanş perdesi barajın memba (giriş) bölgesi ile barajın mansap (çıkış) bölgesi arasındaki çok sayıda konuma yerleştirilmiş ve barajın sızıntı hızının değeri sonlu farklar yöntemi ile analiz edilmiştir. Hidrolik yükün gradyanı alınarak, Düşeydeki sızıntı hızı değeri ve Kaynamaya karşı güvenlik sayıları bulunmuştur. Barajın çıkış bölgesine yerleştirilen palplanş perdesinin Düşey sızıntı hızını en aza indiren ve bundan dolayı Kaynamaya karşı düşey güvenlik sayısını maksimize eden çözüm olduğu görülmüştür.In water currents within the ground, a boiling event may occur if the flow direction is opposite to gravity in the outlet area of the flow floor. To prevent a boiling event, the length of the flow path is increased or a weight filter is used in the area where there is a risk of boiling. Increasing the length of the current path is possible by creating an impermeable layer in the upstream (inlet) section of the dam or by making an impermeable sheet pile wall under the dam. The construction of the sheet pile wall under an impervious dam is expensive and difficult. In this study, the sheet pile wall under the dam wall was placed in various positions between upstream region and downstream (outlet) region of the dam, and the value of the dam's seepage rate was analyzed by finite difference method. Vertical seepage rate values and safety numbers against vertical boiling have been found by taking the gradient of the hydraulic head. It has been seen that the sheet pile wall placed in the exit zone of the dam is the solution that minimizes the leakage rate, and, therefore, maximizes the vertical safety number against boiling
Dental student application of artificial intelligence technology in detecting proximal caries lesions
No full textObjectives: This study aimed to investigate the caries diagnosis performances of dental students after training with an artificial intelligence (AI) application utilizing deep learning techniques, a type of artificial neural network.Methods: A total of 1200 bitewing radiographs were obtained from the institution's database and two specialist dentists labeled the caries lesions in the images. Randomly selected 1000 images were used for training purposes and the remaining 200 radiographs were used to evaluate the caries diagnostic performance of the AI. Then, a convolutional neural network, a deep learning algorithm commonly employed to analyze visual imagery problems, called You Only Look Once, was modified and trained to detect enamel and dentin caries lesions in the radiographs. Forty dental students were selected voluntarily and randomly divided into two groups. The pre-test results of dental caries diagnosis performances of both groups were recorded. After 1 week, group 2 students were trained using an AI application. Then, the post-test results of both groups were recorded. The labeling duration of the students was also measured and analyzed.Results: When both groups' pre-test and post-test results were evaluated, a statistically significant improvement was found for all parameters examined except precision score (p < 0.05). However, the trained group's accuracy, sensitivity, specificity, and F1 scores were significantly higher than the non-trained group in terms of post-test scores (p < 0.05). In group 2 (trained group), the post-test labeling time was considerably increased (p < 0.05).Conclusions: The students trained by AI showed promising results in detecting caries lesions. The use of AI can also contribute to the clinical education of dental students
Direct and indirect toxicity mechanisms of the natural insecticide azadirachtin based on in-silico interactions with tubulin, topoisomerase and DNA
No full textNatural pesticides, which attract attention with safe properties, pose a threat to many non-target organisms, so their toxic effects should be studied extensively. In this study, the toxic effects of Azadirachtin, a natural insecticide derived from Azadirachta indica, were investigated by in-vivo and in-silico methods. In-vivo toxic effects were determined using the Allium test and bulbs were treated with 5 mg/L (0.5x EC50), 10 mg/L (EC50), and 20 mg/L (2xEC50) Azadirachtin. In the groups treated with Azadirachtin, there was a decline in germination-related parameters and accordingly growth was delayed. This regression may be related to oxidative stress in the plant, and the increase in malondialdehyde and proline levels in Azadirachtin-applied groups confirms oxidative stress. Azadirachtin toxicity increased dose-dependently and the most significant toxic effect was observed in the group administered 20 mg/L Azadirachtin. In this group, the mitotic index decreased by 43.4% and sticky chromosomes, vagrant chromosomes and fragments were detected at rates of 83.1 ± 4.01, 72.7 ± 3.46 and 65.1 ± 3.51, respectively. By comet analysis, it was determined that Azadirachtin caused DNA fragmentation, and tail DNA, which was 0.10 ± 0.32% in the control group, increased to 34.5 ± 1.35% in the Azadirachtin -treated groups. These cytotoxic and genotoxic effects of Azadirachtin may be due to direct interaction with macromolecules as well as induced oxidative stress. Azadirachtin has been found to interact in-silico with alpha-tubulin, beta-tubulin, topoisomerase I and II, and various DNA sequences. Possible deteriorations in macromolecular structure and functions as a result of these interactions may cause cytotoxic and genotoxic effects. These results suggest that natural insecticides may also be unreliable for non-target organisms, and the toxic effects of compounds presented as “natural” should also be investigated. © 2024 Elsevier Ltdmg/L Aza application groups, (10.000–80.000
Poly(hexamethylene biguanide) immobilized non-absorbable and antimicrobial PET fiber for surgical suture applications: synthesis, characterization and in vitro cytocompatibility assessment
No full textCerrahi sütürler, cerrahi müdahalelerden sonra yaraları kapatmak amacıyla yaygın olarak kullanılan tıbbi cihazlardır. Cerrahi prosedürler sırasında, sütürler çevredeki mikroorganizmalarla temas ederek bakteriyel biyofilmlerin gelişmesine ve ardından cerrahi alan enfeksiyonlarına (CAE) yol açabilir. Bu nedenle bakteri tutunmasını ve kolonizasyonunu engelleyen sütürlerin kullanılması yara iyileşmesinde oldukça önemlidir. CAE oluşumunu en aza indirmek için triklosan ve klorheksidin gibi antiseptiklerle kaplı antimikrobiyal sütürler kullanılmıştır. Ancak çeşitli antiseptiklere ve antibiyotiklere dirençli bakteri suşlarının ortaya çıkması nedeniyle alternatif antimikrobiyal sütürlerin geliştirilmesine yönelik yeni yaklaşımlar gereklidir. Antimikrobiyal ajanlar arasında, poliheksanid (poliheksametilen biguanid, PHMB) geniş spektrumlu antibakteriyel ve antifungal aktiviteye sahip, düşük toksisiteli ve biyouyumlu katyonik bir antiseptiktir. Bu çalışmada cerrahi dikiş ipliği olarak kullanılmak üzere PHMB immobilize edilmiş polietilen tereftalat (PET) liflerin sentezlenmesi amaçlanmıştır. Sentezlenen modifiye PET lifler SEM, FTIR, DSC ve TGA ile karakterize edilmiştir. Bunlara ek olarak modifier PET liflerin ıslanabirliği ve in vitro degradasyon profili araştırılmıştır. Antimikrobiyal etkinlik testleri için S. aureus ve E. coli bakteri suşları kullanılmıştır. Materyallerin in vitro hücre-uyumluluğu (sitotoksisitesi) TS EN ISO 10993-5 standardına göre MTT testi ile değerlendirilmiştir.Surgical sutures are widely utilized medical devices for the purpose of closing wounds after surgical interventions. During surgical procedures, sutures can come into contact with microorganisms in the surrounding environment, leading to the development of bacterial biofilms and subsequent surgical site infections (SSI). Therefore, the use of sutures that prevent bacterial attachment and colonization is very important in wound healing. Antimicrobial sutures coated with antiseptics such as triclosan and chlorhexidine have been used to minimize SSI formation. However, due to the emergence of bacterial strains resistant to various antiseptics and antibiotics, new approaches to the development of alternative antimicrobial sutures are required. Among antimicrobial agents, polyhexanide (polyhexamethylene biguanide, PHMB) is a cationic antiseptic with broad spectrum antibacterial and antifungal activity, low toxicity and biocompatible. The aim of this study was to synthesize PHMB immobilized polyethylene terephthalate (PET) fibers for use as surgical suture threads. The synthesized modified PET fibers were characterized by SEM, FTIR, DSC and TGA. In addition, the wettability and in vitro degradation profile of the modified PET fibers were investigated. S. aureus and E. coli bacterial strains were used for antimicrobial activity tests. In vitro cytocompatibility (cytotoxicity) of the materials was evaluated by MTT test according to TS EN ISO 10993-5 standard
The Destruction of a Will
No full textVasiyetnamenin yok olması, Türk Medeni Kanunu’nun (TMK) 543’üncü maddesinin ikinci fıkrasında düzenlenmiştir. Vasiyetnamenin kaza sonucunda veya üçüncü bir kişinin kusuruyla yok olması mümkündür. Bu durumda, mirasbırakanın geri alma yönünde bir irade açıklaması bulunmamaktadır. Vasiyetnamenin yok olması, onun hükümden düşmesi için tek başına yeterli görülmemiştir. TMK m. 543/II hükmüne göre, yok olan ve içeriğinin aynen ve tamamen belirlenmesine olanak bulunmayan vasiyetname hükümsüz kalmaktadır. O hâlde, içeriği aynen ve tamamen belirlenebilirse, yok olan vasiyetnamenin hüküm ifade etmesi mümkündür. Vasiyetnamenin yok olmasının tek sonucu bu olmayıp, lehine tasarruf yapılan kimsenin vasiyetnameyi yok eden üçüncü kişiden Türk Borçlar Kanunu’nun 49’uncu maddesine dayanarak tazminat talep etmesi de mümkündür. Ne var ki, vasiyetname içeriğinin aynen ve tamamen ispat edilememesi hâlinde, zarar miktarını tam olarak ispat etmek mümkün olmayacaktır. Ayrıca vasiyetnameyi yok eden kişi, aynı zamanda mirasçı ise mirastan yoksun kalacaktır. Bunun için, mirasçının vasiyetnameyi kasten ve hukuka aykırı şekilde yok etmesi gerekmektedir.The destruction of a will is regulated in the second paragraph of Article 543 of the Turkish Civil Code (TCC). It is possible for the will to be destroyed by an accident or by the fault of a third party. In this case, there is no declaration of will by the testator for revocation. The destruction of the will alone is not deemed sufficient for its nullity. Pursuant to Article 543/II of the TCC, a will that is destroyed and the content of which cannot be exactly and completely determined is null and void. In that case, if its content can be determined exactly and completely, it is possible for the will to be valid. This is not the only consequence of the destruction of the will, and it is also possible for the person in whose favour the will was made to claim compensation from the third party who destroyed the will based on Article 49 of the TCO (Turkish Code of Obligations). However, in the event that the content of the will cannot be exactly and completely proved, it will not be possible to prove the exact amount of damage. In addition, if the person who destroyed the will is also the heir, he will be deprived of the inheritance. For this, the heir must destroy the will intentionally and unlawfully
Observation as a professional tool for early childhood teachers' inquiry habit of mind: an interpretative phenomenological study
No full textThis study aimed at understanding and investigating the lived experiences of early childhood teachers' observation practices as a professional tool. Interpretative phenomenological approach was utilized to investigate participants' experiences deeply from their lived experiences. The current study's participants consisted of five early childhood teachers selected through purposive sampling. The three-interview series involving three separate interviews with each participant was used for data collection and the data was analyzed by interpretative phenomenological analysis. The findings describe participant teachers' observation practices that provide data, how teachers convert data into information, and how they use observational data for decision-making. This study aims to draw attention to the critical role of observation in data-based decision-making and pinpoints practical implications for early childhood teachers
Unit inverse Muth distribution
No full textFen Bilimleri Enstitüsü, İstatistik Ana Bilim DalıGüvenilirlik teorisi, özellikle sistemlerin zaman içindeki davranışlarının anlaşılmasında önemli bir rol oynamaktadır. Bu bağlamda Muth dağılımı, matematiksel özellikleri ve uygulamaları ile dikkat çekmiş ve istatistiksel olarak birçok kullanışlı özelliğe sahip modeller arasında yer bulmuştur. Dağılımın bu özelliklerini göz önünde bulunduran bir dizi araştırmacı tarafından bazı yeni genellemeleri literatüre kazandırılmıştır. Bu çalışmanın ilk kısmında Muth dağılımı, alfa kuvvet dönüştürülmüş Muth dağılımı ve ters Muth dağılımı incelenir. Sonrasında, dağılımın (0,1) reel aralığından değerler alan bir rasgele değişkenin modellenmesinde kullanılabilecek birim ters Muth dağılımı adında yeni bir uzantısı türetilir. Teorik olarak birim ters Muth dağılımın türetilmesinin yanı sıra yeni dağılımın bir dizi istatistiksel özelliği de araştırılır. Dahası, Birim ters Muth dağılımının bilinmeyen parametresi için farklı parametre tahmin metodolojilerine dayalı olarak tahmin ediciler elde edilir. Elde edilen bu tahmin edicilerin bilinmeyen parametreyi tahmin etmedeki başarımı da yine tez de verilen bir dizi simülasyon çalışması ile ortaya çıkarılır.Reliability theory plays an important role, especially in understanding the behavior of systems over time. In this context, the Muth distribution has attracted attention with its mathematical properties and applications and has found itself among the models with many useful statistical features. Some new generalizations of it have been introduced to the literature by several researchers who consider these features of the distribution. In the first part of this study, the Muth distribution, alpha power transformed Muth distribution, and inverse Muth distribution are examined. Next, a new extension of the distribution called the unit inverse Muth distribution is derived, which can be used to model a random variable that takes values from the real range (0,1). In addition to deriving the unit inverse Muth distribution theoretically, several statistical properties of the new distribution are also investigated. Moreover, estimators are obtained for the unknown parameter of the Unit inverse Muth distribution based on different parameter estimation methodologies. The success of these estimators in estimating the unknown parameter is also revealed through a series of simulation studies given in the thesis
Double-Layered Alternative Food Coatings Developed with Mucilage and PDMS
No full textSon yıllarda, malzeme bilimindeki ilerlemelerle birlikte çevre, sağlık ve gıda sektörlerinde karşılaşılan sorunlara doğal çözümler arayışı artmıştır. Atık plastiklerin çevresel kirlilik yaratması ve toksik olmaları büyük endişe kaynağıdır. Bu nedenle, doğal polimer filmlerin geliştirilmesi, özellikle gıda endüstrisinde plastiklerin yerini alabilecek bir alternatif sunar. Bu çalışmada, omega-3, protein, yağ ve lif açısından zengin chia tohumundan elde edilen müsilaj ve polidimetilsiloksan (PDMS) filmlerinin kombinasyonuyla çift katmanlı filmler üretilmiştir. Filmlerin fizikokimyasal özellikleri Fourier dönüşümü kızılötesi spektroskopisi, termogravimetrik analiz, taramalı elektron mikroskobu ve enerji dağılımlı X-ışınları spektroskopisi gibi yöntemlerle karakterize edilmiştir. Son olarak, filmlerin su temas açısı ölçülmüş olup, çift katmanlı filmlerin iç tarafının hidrofilik dış tarafının ise hidrofobik özelliklere sahip olduğu gösterilmiştir. Bu çalışma, çift katmanlı müsilaj-PDMS filmlerinin potansiyel olarak gıda paketleme uygulamalarında kullanılabilir bir alternatif ürün olabileceğini ortaya koymaktadır.In recent years, in parallel with advancements in materials science, there has been a growing pursuit of natural solutions to address environmental, health, and food industry challenges. The environmental pollution and toxicity associated with waste plastics have raised significant concerns. Therefore, the development of natural polymer films, particularly those derived from chia seeds rich in omega-3, protein, oil, and fiber, presents an alternative that could replace plastics in the food industry. In this study, double-layer films were produced by combining mucilage extracted from chia seeds and polydimethylsiloxane (PDMS). The physicochemical properties of the films were characterized using methods such as Fourier-transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Finally, the water contact angle of the films was measured, demonstrating that the inner side of the double-layer films is hydrophilic, while the outer side exhibits hydrophobic properties. This study suggests that dual-layer mucilage-PDMS films could be a potentially viable alternative in food packaging applications
Evaluation of systemic inflammation markers in patients with rhinitis
No full textBackground: Rhinitis affects the majority of the population. It may generate localized nasal mucosal inflammation via allergic (AR) or nonallergic (NAR) processes, but it is unknown if this might also result in systemic inflammation, which can raise morbidity and death. Using current serum inflammatory markers, we sought to investigate systemic inflammation in patients with chronic rhinitis. Methods: In this retrospective case-control study, we included 439 patients with newly diagnosed AR (n = 179), NAR (n = 157), and 103 healthy individuals. Inflammation-related blood parameters were collected as lymphocyte/monocyte ratio (LMR), neutrophil/lymphocyte ratio (NLR), eosinophil/neutrophil ratio (ELR), and systemic immune inflammation index (SII). Results: All groups were similar in terms of age, gender, and body mass index. Neutrophil counts were significantly higher both in AR and NAR groups compared to controls (4.51 +/- 0.09, 4.54 +/- 0.1 vs. 3.73 +/- 0.1, p < 0.001). NLR (1.91 +/- 0.56, 1.89 +/- 0.61, 1.61 +/- 0.59, p < 0.001), LMR (5.76 +/- 0.17, 5.93 +/- 0.17, 5.1 +/- 0.15, p = 0.005), ELR (0.1335 +/- 0.007, 0.0999 +/- 0.006, 0.12 +/- 0.009, p = 0.003), SII (533.3 +/- 16.6, 558.1 +/- 20.9, 479.9 +/- 22.2, p = 0.035), and CRP (1.44 +/- 0.09, 1.67 +/- 0.09, 0.87 +/- 0.04, p < 0.001) were significantly higher in AR and NAR groups than the controls, respectively. SII (r = 0.146, p = 0.007) and ELR (r = 0.254, p < 0.001) were correlated with the presence of asthma. Conclusion: We found that systemic circulation of inflammatory cells was significantly increased in rhinitis with/without allergy compared to the control group. This study showed that not only AR, but also NAR triggers a systemic increase of inflammation which supports the link between rhinitis and comorbid conditions such as asthma. Therefore, effective treatment may be suggested for local inflammation and its systemic manifestations