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Investigation of wear performance of R260 and R350HT rails after vibratory peening and ultrasonic nanocrystal surface modification
No full textIn this study, the effects of ultrasonic nanocrystal surface modification (UNSM) and severe vibratory peening (SVP) of R260 and R350HT rail steels were investigated. The surface treatments resulted effective grain size reduction in the surface layers. While surface roughness decreased due to UNSM, SVP generally increased surface roughness. SVP demonstrated a significant effect on the microhardness. While the microhardness of the untreated sample was around 320 HV, the microhardness of R350HT peened for 4 h and 10 h increased to 390 and 470 HV, respectively. The UNSM treated specimens showed significant improvements, especially in surface roughness, which improved the wear performance. SVP treated specimens showed significant improvements in friction and wear performance due to the improvement on microhardness.Karabuk University Scientific Research Projects Coordination Unit [KBUBAP-23-KP-030]The authors wish to thank Karabuk University Scientific Research Projects Coordination Unit with a project number of KBUBAP-23-KP-030
Investigating the Effect of The Educational Games on the Conceptual Development of Fourth-Grade Primary School Students
No full textBu çalışmada, ilkokul 4. sınıf öğrencilerine 'Maddenin Özellikleri' ünitesinin 'Maddeyi Niteleyen Özellikler' konusuna yönelik tasarlanan eğitsel oyunların öğrencilerin kavramsal gelişimine etkisi ve eğitsel oyunun uygulanabilirliği konusunda öğretmen görüşünü ortaya çıkarmak amaçlanmıştır. Çalışmada 'Basit Deneysel Yöntem' kullanılmıştır. Veri toplama aracı olarak; kavramsal anlama testi ve yarı yapılandırılmış mülakattan yararlanılmıştır. Araştırmacı tarafından çalışma grubuna kavramsal anlama testi öğretim öncesi uygulanmış ve eğitsel oyun ile öğretim süreci tamamlandıktan sonra son test olarak uygulanmıştır. İlgili konuya yönelik tasarlanan oyunla ilgili öğretmen görüşü yarı yapılandırılmış mülakatla tespit edilmiştir. Kavramsal anlama testindeki açık uçlu soruların analizinde Abraham ve diğerleri (1992) tarafından geliştirilen anlama seviyesi kategorileri, kavramsal anlama testinde yer alan yapılandırılmış grid sorularının analizinde, cevaplarının puanlamasında alan yazında (Bahar vd., 2002) yer alan formül kullanılmıştır. Araştırma sonucunda eğitsel oyunun öğrencilerin kavramsal gelişiminde anlamlı etkide bulunduğu (z:3,408; pThis study, it was aimed to reveal the effect of educational games designed for 4th-grade primary school students on the conceptual development of students' development of the 'Properties of Matter' topic of the 'Properties of Matter' unit and to reveal the teacher's opinion on the applicability of the educational game. 'Pre Experimental Method' was used in this study. Conceptual understanding test and semi-structured interview were used as data collection tools. The researcher applied the conceptual understanding test to the study group before the instruction and applied it as a post-test after the instructional process with the educational game was completed. The teacher's opinion about the game designed for the related subject was determined through a semi-structured interview. The comprehension level categories developed by Abraham et al. (1992) were used to analyze the open-ended questions in the conceptual understanding test, and the formula in the literature (Bahar et al., 2002) was used to analyze the structured grid questions in the conceptual understanding test and to score their answers. As a result of the research, it was concluded that the educational game had a significant effect on the conceptual development of the students (z: 3,408;
Barriers of Blockchain in Sustainability Reporting: An Application With Fuzzy AHP
No full textSustainability Reporting, which is a non-financial reporting, is an important practice that includes measuring and reporting the social, environmental, and economic impacts of an organization. The accuracy and transparency of these reports is a crucial factor for consumers and investors. Blockchain technology is seen as a tool that can increase the accuracy and transparency of sustainability reporting by offering a decentralized and transparent system. However, there are barriers to the use and adoption of blockchain technology. Studies reveal technological, institutional, organizational, and environmental factors. Integration issues between different blockchain networks can threaten data integrity and accuracy. In addition, problems such as high energy consumption and low transaction speed can also affect the sustainability of blockchain technology. In the study, the barriers to the use of blockchain technology in sustainability reporting were analysed. For this purpose, the criteria determined were presented to expert opinions and criterion weighting was made with the Fuzzy AHP method. The most important results from the study show that resistance to change, the idea that the system works at a limited capacity, and the lack of trust in the system are the most affecting barriers preventing the adoption of blockchain technology in this space
Experimental and optimization study of nanofluid utilized PVT systems with hydrocarbon based PCM: An Energetic-exergetic approach
No full textCooling of photovoltaic thermal (PVT) systems is crucial for enhancing electrical efficiency by reducing the operating temperature of photovoltaic modules. Elevated temperatures negatively affect the performance of PV cells, leading to a decline in energy conversion efficiency. Photovoltaic thermal (PVT) systems, hybrid technologies that generate electricity and heat, are crucial for efficient energy conversion. This study uniquely explores the performance of a PVT system by integrating phase change materials (PCMs) and nanofluids in PVT systems combined with optimization analysis. By combining these advanced cooling methods, both electrical and thermal efficiencies are significantly optimized, demonstrating the potential for improved energy conversion in PVT systems. Within this scope, three identical systems-water-cooled, nanofluid-cooled, and a combination of nanofluid cooling with PCM-were analyzed regarding electrical, thermal, and exergy efficiencies. Identical panels were placed side by side and tested. Additionally, an optimization analysis has been conducted to enhance the performance of each panel by evaluating the thermal and electrical efficiency values obtained from experimental data based on system parameters and levels. In addition, thermogravimetric analysis and differential scanning calorimetry were conducted to determine the melting point of the Hydrocarbon-Based PCM. Compared with traditional methods, these analyses conducted in conjunction with the experimental study provide a more reliable basis for performance evaluation studies of PVT systems. The results of the experimental study showed that Nanofluid-Integrated PVT with Hydrocarbon-Based PCM achieved 11.7 %, 11.6 % and 10.6 % higher electrical efficiency, overall exergy and electrical exergy respectively, compared to the water-cooling method. Additionally, a 6.6-fold increase in thermal efficiency and a 4.4-fold increase in overall efficiency were observed. Similarly, compared to the nanofluid cooling method, this combination provided 4.9 %, 5.9-fold and 3.47 % improvements in the electrical, thermal and overall exergy efficiencies metrics. The results of the optimization analysis revealed that the combination of PCM and nanofluids ensures greater stability in electrical efficiency values under high-temperature differences. It was also observed that solar irradiance is the most influential parameter affecting efficiency. The obtained results demonstrate that the nanofluid-cooled system integrated with PCM has a significant impact on enhancing the performance of PVT systems. The combined use of nanofluid and PCM considerably improves all efficiency parameters
Deciphering the Anticancer, Antioxidant, Enzyme Inhibition Potentials, and Phytochemical Compositions of Some Endemic Centaurea Species
No full textPlants have been used in traditional medicine for centuries, providing a variety of biological benefits, including antioxidant and anticancer activity, due to their phytochemical composition. This study investigates the biological activity and chemical composition of Centaurea saligna, Centaurea bingoelensis, and Centaurea pyrrhoblephara, key species of the Asteraceae family, to explore their potential for developing novel therapeutic strategies. Methanol extracts of these species were analyzed for their inhibitory effects on alpha-glucosidase, AChE, and BuChE enzymes. Their lipophilic components were characterized using GC-MS, phenolic profiles via Orbitrap HPLC-HRMS, and total phenol and flavonoid contents were quantified using established methods. Antioxidant activities were evaluated through DPPH, ABTS, ferric ion reducing, and ferrous ion chelating assays. Cytotoxic effects were assessed on HT-29 colorectal and A549 lung cancer cells through WST-1 analysis, determining IC50 values. In addition, anticancer activity findings were supported by colony survival and cell migration analyses. Apoptotic activity of the applied treatments was observed by AO/EB dual staining, caspase-3 ELISA, and Western blot analysis. Notably, the extracts significantly induced apoptosis in HT-29 cells, evidenced by increased apoptotic indices, cleaved PARP, and p53 expression, with C. pyrrhoblephara exhibiting the strongest proapoptotic activity.Scientific Research Projects Coordination Unit of Bingol University [BAP-FEF.2021.008]The present study was supported by the Scientific Research Projects Coordination Unit of Bingol University (Project no: BAP-FEF.2021.008)
Understanding the impact of external risk factors on business performance: a comprehensive analysis
No full textPurpose-The purpose of this paper is to analyze the impact of various external risk factors on companies operating in the technology sector. By understanding these impacts, companies can better prepare and adapt their strategies to mitigate potential negative impacts and take advantage of emerging opportunities. Design/methodology/approach-In the research, the evaluation of non-business risk factors was made with the F-DEMATEL method. While carrying out these procedures, 10 expert opinions were taken. Experts work in companies operating in the technology sector. All of them have university education or above. A total of 4 participants are female and 6 participants are male. The oldest participant is 57 years old and the youngest is 34 years old. When looking at the time spent working in the sector, the most senior expert said that he has been in the sector for 33 years. The participant with the least seniority has been working in the sector as a manager for 4 years. Findings-The analysis reveals many notable findings regarding the impact of external risk factors on technology companies. In particular, the fact that changes in demand conditions emerge as the second most effective factor underlines the importance of market dynamics in shaping company performance. Additionally, the country's political situation and changing competitive conditions have been identified as important determinants of risk exposure, highlighting the interconnection between macro-level factors and company-level outcomes. Additionally, natural risks and sudden changes in input prices are highlighted as persistent threats, necessitating proactive risk management measures to mitigate possible disruptions. Research limitations/implications-Despite its contributions, this study has some limitations that should be considered. First, the findings are based on expert opinions in the technology sector and may not fully reflect the diversity of risk perceptions across different industries or regions. Future research may therefore benefit from including a larger sample of companies or using quantitative methodologies to validate the findings. Practical implications-Companies that are aware of external risk factors can proactively develop risk management strategies to minimize risk exposure and protect their operations. For example, strategies such as diversifying foreign exchange risk, closely monitoring market demand trends and investing in disaster preparedness measures can help mitigate the negative consequences of external risks. Additionally, understanding the relative importance of risk factors should be taken into account by companies in effectively prioritizing their resource allocation and decision-making efforts. Originality/value-In particular, the research adds original insights to existing knowledge by empirically examining the relative importance of external risk factors within the technology sector. Synthesizing the perspectives of industry experts, the research provides a nuanced understanding of the multifaceted risks facing technology companies and offers practical implications for strategic decision-making. Hierarchical ranking of risk factors adds value by guiding companies to prioritize risk mitigation efforts and allocate resources effectively, thereby increasing corporate resilience and long-term sustainability
WEIGHTING SMART CITY MANAGEMENT CRITERIA WITH ANP METHOD
No full textAkıllı şehirler, teknoloji kullanılarak oluşturulmuş ögelerle insanların yaşam kalitelerini artırıp sürdürülebilir yerleşim alanları oluşturmaktadır. Akıllı şehir yönetimi, ilgili hizmet alanlarında verimli ve sürdürülebilir çalışmalarla ilerleyebilmek için kamusal, özel ve sivil paydaşların ortaklaşmasını ifade etmektedir. Yönetişim, strateji, politika yönetimi, iş yönetimi ve bütüncül hizmet yönetimi gibi alt sistemlerin verimlerini artırıp şehrin ana sisteminde sürdürülebilirlik hedeflenmektedir. Problemin çok kriterli yapısı göz önünde bulundurularak önerilen modelde Analitik Ağ Süreci (ANP) yöntemi, Çok Kriterli Karar Verme (ÇKKV) yöntemlerinden biri olarak kullanılmıştır. Literatürde akıllı şehir yönetimi kriterlerinin öncelik değerlendirilmesi yapıldığı bir çalışmaya rastlanmamıştır. Bu yüzden yapılan çalışma diğer yapılacak çalışmalara öncülük edecektir. Ayrıca bu çalışma önerilen modelde kullanılan yöntem açısından probleme ve literatüre önemli bir katkı sunmaktadır. Super Decisions programı ile ANP yöntemi çözüme ulaştırılmıştır.Smart cities improve people's quality of life and create sustainable residential areas with elements created using technology. Smart city management refers to the partnership of public, private and civil stakeholders in order to move forward with efficient and sustainable work in the relevant service areas. It aims to increase the efficiency of subsystems such as governance, strategy, policy management, business management and holistic service management and to achieve sustainability in the main system of the city. Considering the multi-criteria nature of the problem, the Analytic Network Process (ANP) method was used as one of the Multi-Criteria Decision Making (MCDM) methods in the proposed model. In the literature, there is no study in which smart city management criteria are prioritized. Therefore, this study will pioneer other studies. In addition, this study makes an important contribution to the problem and the literature in terms of the method used in the proposed model. The ANP method was solved with the Super Decisions program
Investigation of optical properties of antireflective coating applied to ophthalmic optical lenses
No full textOptik lensler, sağlık, enerji, otomotiv, elektronik, bilişim, savunma gibi pek çok alanda yaygın olarak kullanılmaktadır. Sağlık sektöründe gözlerde oluşan refraksiyon kusurlarının düzeltilmesi için geliştirilen ve hammaddelerine göre plastik (organik, polimer) ve mineral (cam) olmak üzere iki ana grupta üretilen optik lenslerin tasarımında arzu edilen özellikler; iyi görme alanı, yüksek kırma gücü, sağlamlık, düşük yoğunluk, UVR koruma sağlaması, görünür ışıkta geçirgenlik değerinin standarda uygun olması, abbe değerinin yüksek olması ve lens aberasyonlarını azaltmak için kaplama özelliklerinin iyi olmasıdır. Bu ihtiyaçlara paralel olarak kullanıcıların ihtiyaçlarına göre oftalmik optik lenslerin yüzeylerine tek tabakalı veya çok tabakalı olarak, çeşitli özelliklere sahip kaplamalar uygulanmaktadır. Bu kaplamalar yansıma önleyici (AR) kaplama, mavi kaplama (blue filtre), sertlik kaplaması, temizlik kaplaması, su itici, ayna kaplaması, renk kaplama, fotokromik kaplama, buharlanma önleyici kaplamalardır. Bunlar arasında Anti-Refle (AR) kaplamalar yansımayı azaltmak, görme kalitesini ve estetiği arttırmak ve bazı çalışmalarda geçirgenliği arttırmak amacıyla sıkça kullanılmaktadır. AR kaplamalar gözlük camlarında oluşan yansımaları azaltıp ışık geçirgenliğini artırarak gözlük kullanıcılarına daha net bir görüş imkânı sağlamaktadır. Oftalmik optik lenslere uygulanan diğer bir kaplama çeşidi olan mavi kaplamalar veya mavi ışık filtreleri led ekranlardan, elektromanyetik radyasyon kaynaklarından ve diğer kaynaklardan gelen mavi ışığı bloke ederek kullanıcıyı mavi ışığın rahatsız edici etkisinden korurken görüş kalitesini arttırmaktadır. Bu çalışmada, üzerlerine AR kaplamalar uygulanan oftalmik optik lensler oftalmik optik lenslerin optik özellikleri incelenerek ışık geçirgenlikleri tespit edilecektir. Bu amaçla temin edilen farklı indislere sahip oftalmik optik AR kaplamalı lenslerin ışık geçirgenlikleri UV-VIS spektrofotometre ile ölçülecektir. AR kaplamalı lenslerin ışık geçirgenlikleri literatürle kıyaslamalı olarak incelenecektir. Optik ve optisyenlik alanında literatüre katkı sağlaması amaçlanan tez çalışmasından elde edilen çıktıların aynı zamanda göz sağlığının korunmasına yönelik çalışmalara katkı sağlaması hedeflenmektedir.Optical lenses are widely used in many fields such as health, energy, automotive, electronics, informatics and defence. The desired features in the design of optical lenses developed for the correction of refractive errors in the eyes in the health sector and produced in two main groups as plastic (organic, polymer) and mineral (glass) according to their raw materials are; good visual field, high refractive power, robustness, low density, UVR protection, transmittance value in visible light in accordance with the standard, high abbe value and good coating properties to reduce lens aberrations. In parallel with these requirements, coatings with various properties are applied to the surfaces of ophthalmic optical lenses as monolayer or multilayer according to the needs of the users. These coatings are anti reflection (AR) coating, blue coating (blue filter), hardness coating, cleaning coating, water repellent, mirror coating, colour coating, photochromic coating, anti-evaporation coating. Among these, Anti-Refle (AR) coatings are frequently used to reduce reflection, improve visual quality and aesthetics and increase transmittance in some studies. AR coatings provide a clearer vision to eyeglass wearers by reducing reflections and increasing light transmittance. Blue coatings or blue light filters, another type of coating applied to ophthalmic optical lenses, block blue light from LED screens, electromagnetic radiation sources and other sources, protecting the user from the disturbing effect of blue light while improving the quality of vision. In this study, the light transmittance of ophthalmic optical lenses with AR coatings applied on them will be determined by analysing the optical properties of ophthalmic optical lenses. For this purpose, the light transmittances of ophthalmic optical AR coated lenses with different indices will be measured by UV-VIS spectrophotometer. The light transmittances of AR coated lenses will be analysed in comparison with the literature. It is aimed that the outputs obtained from the thesis study, which is aimed to contribute to the literature in the field of optics and opticianship, will also contribute to the studies for the protection of eye health
Development of artificial intelligence and multi-sensor-based dexterity assessment system: performance evaluation
No full textManual dexterity tests are essential for diagnosing diseases and evaluating professional skills that require fine motor control. Traditional assessments often depend on expert supervision, leading to delays, subjectivity, and inaccuracies. This study introduces an automated dexterity assessment system that integrates multiple sensors and artificial intelligence algorithms for high-precision evaluation. The system classifies hand movements, analyzes muscle contraction levels, and determines hold-release durations using electromyography (EMG), inertial measurement units (IMU), and image processing techniques. An expert system interprets the multimodal sensor data and presents the results to clinicians. A performance evaluation with 20 participants demonstrated the system's capability to assess hand dexterity automatically and accurately.Scientific and Technological Research Council of Turkiye [122E017]This work has been supported by The Scientific and Technological Research Council of Turkiye (project number: 122E017)
Evaluation of anti-cancer and anti-enzyme activities of imidazole derivative molecules with theoretical calculations
No full textNitrogen-containing heterocycles, known for their biological activity, were synthesized as four novel imidazolebased compounds via the reaction of guanyl hydrazones with 2-bromoacetyl naphthalene. The aim of this study was to synthesize and characterize these compounds and evaluate their potential as cholinesterase inhibitors and anticancer agents. Structural elucidation was performed using 1H NMR, 13C NMR, FTIR, and MS. All compounds exhibited strong AChE and BChE inhibitory activities, with Ki values ranging from 131.44 to 415.54 nM (AChE) and 95.74 to 154.62 nM (BChE). IC50 values confirmed potent inhibition. MTT assays demonstrated dose-dependent antiproliferative effects, with greater cytotoxicity observed in A2780 ovarian cancer cells than in MIA PaCa-2 pancreatic cells. In silico studies, including Gaussian (B3LYP, HF, M062X/6-31++G(d,p)), molecular docking, and ADME/T analyses, supported the pharmacological potential of these compounds. These findings highlight their promise as candidates for further development in cholinesterase inhibition and cancer therapy.Scientific Research Project Fund of Sivas Cumhuriyet University (CUBAP) [RGD-020]This work was supported by the Scientific Research Project Fund of Sivas Cumhuriyet University (CUBAP) under the project number RGD-020