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Investigation of the effects of ferrochrome plant flue dust on portland cement hydration and mechanical properties
Get PDFPortland çimento üretimi, küresel karbondioksit emisyonlarının %5-7'sinden sorumludur. Ayrıca büyük miktarlardaki ferrokrom atıklarının depolama alanlarının yetersizliği ve çevresel etkileri nedeniyle önemli bir sorun olduğu ve bu ürünlerin inşaat malzemesi olarak kullanılmasıyla çevresel ve sosyo-ekonomik fayda sağlanabileceği düşünülmektedir. Bu nedenle ferrokrom üretimi sırasında oluşan ferrokrom cürufu ve ferrokrom baca tozu gibi yan ürünleri geri dönüştürmek ve karbondioksit emisyonlarını azaltmak için çimento teknolosinde yoğun araştırmalar devam etmektedir. Bu çalışmada, ferrokrom baca tozunun (FBT) sürdürülebilir çimento üretimi için tamamlayıcı bir çimento malzemesi olarak kullanılabilirliği araştırılmaktadır. Çalışmanın ilk aşamasında, Portland çimento (PÇ) ve FBT'nin fizikokimyasal özellikleri farklı analiz teknikleri kullanılarak belirlenmiştir. İkinci aşamada, PÇ'ye ağırlıkça %0, %2,5, %5, %7,5 ve %10 oranlarında FBT ikame edilerek 5 tip çimento elde edilmiştir. Daha sonra bu çimentolarla hazırlanan çimento hamurlarının su ihtiyaçları, genleşme ve priz süreleri standart çimento deneyleriyle belirlenmiştir. Üçüncü aşamada, hidratasyonun 28. gününde X-ışını kırınımı (XRD), fourier dönüşümlü kızılötesi spektroskopisi (FT-IR), eş zamanlı termal analiz (DTA/TGA), taramalı elektron mikroskobu ve enerji dağılımlı X-ışını spektroskopisi (SEM/EDS) gibi ileri analitik teknikleriyle reaksiyon ürünleri izlenmiştir. Son aşamada, harçların 1, 2, 7, 28 ve 90. günlerdeki basınç dayanımları tespit edilmiştir. FBT ile hazırlanan çimento hamurlarının mikro yapı incelemesi, kalsiyum silikat hidrat (C-S-H), C-S-H'nın ışınsal lifsi yapısı, kalsiyum hidrat (CH) ve hegzagonal yapıdaki etrenjit (AFt) kristallerinin heterojen bir dağılımla kompak bir yapı oluşturduğunu göstermiştir. Ayrıca FBT'nin alüminosilikat bileşimlerinin yanı sıra zengin bir MgO kaynağı olması, erken yaşlardaki basınç dayanımlarının artmasına neden olmuştur. Sonuç olarak bu veriler, çevre kirliliğine ve sağlık tehlikesine neden olan FBT'nin çimento ikame malzemesi olarak kullanılması sayesinde ekonomik ve ekolojik yararların sağlanabileceğini göstermektedir.Portland cement production is responsible for 5-7% of global carbon dioxide emissions. It is also considered that large quantities of ferrochrome wastes are a significant problem due to the lack of storage areas and environmental impacts, and that environmental and socio-economic benefits can be achieved by using these products as construction materials. For this reason, intensive researches are continuing in cement technology to recycle by-products such as ferrochrome slag and ferrochrome flue dust generated during Ferrochrome production and to reduce carbon dioxide emissions. In this study, the usability of ferrochrome flue dust (FBT) as a supplementary cement material for sustainable cement production is investigated. In the first stage of the study, the physicochemical properties of Portland cement (PC) and FBT were determined using different analysis techniques. In the second stage, 5 types of cement were obtained by substituting FBT into PC at rates of 0%, 2.5%, 5%, 7.5% and 10% by weight. Then, the water requirements, expansion and setting times of the cement pastes prepared with these cements were determined by standard cement tests. In the third stage, reaction products were monitored on the 28th day of hydration by advanced analytical techniques such as X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), simultaneous thermal analysis (DTA/TGA), scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM/EDS). In the final stage, the compressive strengths of the mortars at 1, 2, 7, 28 and 90 days were determined. Microstructure analysis of cement pastes prepared with FBT showed that calcium silicate hydrate (C-S-H), radial fibrous structure of C-S-H, calcium hydrate (CH) and hexagonal etrengite (AFt) crystals formed a compact structure with a heterogeneous distribution. In addition, the fact that FBT is a rich source of MgO as well as aluminosilicate compositions caused an increase in compressive strength at early ages. In conclusion, these data show that economic and ecological benefits can be achieved by using FBT, which causes environmental pollution and health hazards, as a cement substitution material
Kronik Bel Ağrısı Olan Hastalarda Ağrı Fonksiyonel Kısıtlılık ve Uyku Kalitesinin Değerlendirilmesi
Get PDFAMAÇ: Bu çalışma, kronik bel ağrısı olan hastalarda ağrıya bağlı yetersizlik, uyku kalitesi ve çeşitli demografik ve klinik özellikler arasındaki ilişkiyi değerlendirmeyi amaçlamaktadır. Çalışmanın bilime katkısı, kronik bel ağrısı olan hastaların yönetiminde biopsikososyal modelin önemine dikkat çekmektir. GEREÇ ve YÖNTEMLER: Çalışmaya, en az 6 haftadır geçmeyen bel ağrısı şikayetiyle Düzce Üniversitesi Beyin Cerrahisi polikliniğine başvuran 151 hasta dahil edilmiştir. Ağrı, görsel analog skalar kullanılarak istirahat, uyku ve yürüme ağrıları şeklinde değerlendirilmiştir. Fonksiyonel kısıtlılık, geçerliliği ve güvenilirliği sağlanmış bir ağrı fonksiyonel kısıtlılık anketi ile, uyku kalitesi ise Pittsburg Uyku Kalitesi İndeksi ile değerlendirilmiştir. BULGULAR: Çalışmaya katılan hastaların yaş ortalaması 46.68 yıl olup, %55’i kadın ve %45’i erkektir. Erkekler, kadınlara kıyasla istatistiksel olarak anlamlı düzeyde daha yüksek istirahat ağrısı (p=0.044), mesleki fonksiyon kaybı (p=0.002) ve daha kötü uyku kalitesi (p=0.041) bildirmiştir. Kronik hastalığı olan hastalar, kronik hastalığı olmayanlara kıyasla daha yüksek istirahat ağrısı (p=0.027) ve daha kötü uyku kalitesi (p=0.002) bildirmiştir. İlaç kullanan bireyler, kronik hastalıklara bağlı ilaç (örneğin, hipertansiyon, diyabet) veya düzenli ağrı kesici ilaç kullanan hastalardır. İlaç kullanan bireyler, kullanmayanlara göre daha yüksek istirahat ağrısı (p=0.001) ve daha kötü uyku kalitesi (p<0.001) bildirmiştir. Sigara içenler, içmeyenlere göre daha yüksek istirahat ağrısı (p=0.042) ve daha kötü uyku kalitesi (p=0.029) bildirmiştir. Ağrı ve ağrıya bağlı yetersizlik arasında pozitif ve anlamlı korelasyonlar bulunmuştur. SONUÇ: Bu çalışma, kronik bel ağrısı olan hastalarda ağrı, uyku kalitesi ve çeşitli demografik ve klinik faktörler arasındaki karmaşık etkileşimi vurgulamaktadır. Bu bulgular, kronik bel ağrısının yönetiminde biopsikososyal yaklaşımların önemini ve bireyselleştirilmiş tedavi stratejilerinin gerekliliğini göstermektedir
EZH2 expression in colorectal carcinoma: an evaluation of clinicopathological and prognostic value
Get PDFBackgroundEnhancer of zeste homolog 2 (EZH2), the catalytic subunit of Polycomb Repressive Complex 2, catalyzes trimethylation of histone H3 lysine 27 and has been implicated in tumor progression.AimOur study aims to assess the relationship between EZH2 expression and clinicopathologic data, and survival in colorectal carcinomas (CRC).Materials and methodsEZH2 immunohistochemistry was performed on tumor blocks from 124 CRC patients. Based on H-scores, cases were stratified into low- and high-expression groups. EZH2 status was correlated with demographic, clinical, and pathologic features, and overall survival was analyzed with the Kaplan-Meier method and log-rank test.ResultsA total of 124 cases of CRC; 12 (9.7%) cases were classified as low EZH2 expression, and 112 (90.3%) cases were classified as high EZH2 expression. A significant association was found between EZH2 expression and microsatellite stability. High EZH2 expression was significantly enriched in microsatellite-stable tumors (p = 0.007) and in left-sided lesions (p = 0.049). No significant associations were detected with sex, stage, grade, lymph-node status, or vascular invasion. Kaplan-Meier analysis revealed no difference in overall survival between low- and high-EZH2 groups (log-rank p = 0.47; hazard ratio = 1.13, 95% CI 0.45-2.85). EZH2 staining was uniformly strong in normal mucosa and adenomas, mirroring the high expression observed in most CRCs.ConclusionsEZH2 is highly expressed across the normal-adenoma-carcinoma sequence and, in our cohort, was not linked to overall survival or to most clinicopathologic parameters in CRC. The lower expression observed in a subset of MSI-H tumors warrants further investigation; present evidence remains insufficient to establish EZH2 as an independent prognostic biomarker.Erzincan University Scientific Research and Project Office [910]This study was supported by Erzincan University Scientific Research and Project Office (Project ID:910)
Political Iconography in Contemporary Art
Get PDFIn a contemporary society characterised by fragmentation and complexity, political iconography has re-emerged as a potent tool for challenging authority and exploring themes of identity and dissent. This study examines the ways in which artists such as Banksy, Barbara Kruger, Ai Weiwei, and Shepard Fairey employ iconography not merely as a vehicle for conveying imagery but also as a transformative language of resistance. These artists use physical and digital spaces to amplify sociopolitical tensions, embedding complex messages within symbols. This approach encourages audiences to confront the underlying power structures and collective identities. While political iconography is often associated with the concepts of power, authority, rebellion, and propaganda, theoretical approaches to iconography frequently focus on its structural principles rather than its role within political ideologies, state control, or activist art. This study aims to address this lacuna by examining how visual symbols function within the frameworks of oppression and resistance, thereby revealing their role as instruments of ideological negotiation. By employing a targeted approach that combines case studies and visual analysis of four artists with distinct approaches, this research demonstrates that visual symbols are not merely aesthetic; rather, they serve as influential agents within the collective consciousness. The findings indicate that this evolving visual lexicon not only reflects contemporary issues but also serves as a catalyst for public engagement, thereby blurring the boundaries between observer and participant. By analysing the strategic use of symbols in visual activism, this study contributes to an understanding of iconography as an essential element of modern resistance and examines the potential of non-verbal critique in the digital age
The use of decision support systems in the process of export market selection
No full textKüresel rekabetin yoğunlaştığı ve teknolojinin iş yapma biçimlerini dönüştürdüğü günümüzde, ihracat firmaları için doğru pazarlara yönelmek her zamankinden daha stratejik bir önem taşımaktadır. Özellikle elektrik-elektronik, makine ve otomotiv gibi yüksek katma değerli sektörlerde faaliyet gösteren işletmeler, sadece ürün kalitesiyle değil, aynı zamanda doğru pazar seçimi ve zamanında karar alma becerileriyle de uluslararası başarılarını şekillendirmektedir. Bu noktada, ihracat sürecinde alınan kararların yalnızca sezgi ve deneyimlere değil, veri temelli ve sistematik analizlere dayanması gerekmektedir. Geleneksel karar destek sistemleri, değişkenliği yüksek ve çok boyutlu ihracat ortamında yetersiz kalabilmektedir. Artan veri çeşitliliği ve hacmi, karar vericilerin daha ileri analiz araçlarına ihtiyaç duymasına yol açmıştır. Bu ihtiyaç doğrultusunda yapay zekâ temelli yöntemler, son yıllarda dış ticaret kararlarının yönetiminde önemli bir rol oynamaya başlamıştır. Özellikle makine öğrenmesi tabanlı algoritmalar, ülkelerin ekonomik, ticari, lojistik ve sektörel göstergelerini aynı anda değerlendirerek stratejik içgörüler üretebilmektedir. Bu tez çalışması, "İhracat Pazar Seçimi Sürecinde Karar Destek Sistemlerinin Kullanımı" başlığı altında, Türkiye'deki bir ihracat firmasının elektrik-elektronik, makine ve otomotiv sektörlerinde pazar seçimini yapay zekâ destekli veri analitiği yöntemleriyle değerlendirmeyi amaçlamaktadır. Çalışmada, farklı ülkelere ait ekonomik göstergeler; ülkelerin genel dış ticaret verileri, Türkiye ile sektörel ikili ticaret verileri, ticaret kolaylığı ve lojistik performans gibi birçok değişken bir araya getirilerek analiz edilmiştir. Bu kapsamda, öz düzenleyici haritalar (Self-Organizing Maps - SOM) ve k-means (k-ortalamalar) gibi yapay zeka öğrenmesine dayalı kümeleme analizi teknikleri kullanılarak, benzer özelliklere sahip ülkeler gruplandırılmış, ardından her kümenin ihracat potansiyeli TOPSIS yöntemiyle değerlendirilmiştir. Bu analizler, sadece potansiyel pazarları tanımlamakla kalmamış; Türkiye'nin mevcut ihracat yapısıyla model sonuçları kıyaslanarak, karar destek sistemlerinin doğruluğu da değerlendirilmiştir. Tezin bulguları, ihracat kararlarının daha sağlıklı ve hızlı alınmasını sağlayan yapay zekâ destekli sistemlerin firmalara sunduğu avantajları ortaya koymayı hedeflemektedir. Elde edilen sonuçların hem akademik literatüre katkı sunması hem de ihracat stratejisi geliştiren uygulayıcılara yol göstermesi beklenmektedir.In today's world, where global competition is intensifying and technology is transforming business practices, targeting the right markets has become more strategically important than ever for export-oriented companies. Especially for firms operating in high value-added sectors such as electrical-electronics, machinery, and automotive, international success is shaped not only by product quality but also by effective market selection and timely decision-making capabilities. At this point, decisions made during the export process must be based not solely on intuitive experience but also on data-driven and systematic analyses. Traditional decision support systems often fall short in highly variable and multidimensional export environments. The increasing variety and volume of data have created a need for more advanced analytical tools for decision-makers. In response to this need, artificial intelligence (AI)-based methods have begun to play a significant role in managing foreign trade decisions in recent years. In particular, machine learning-based algorithms are capable of simultaneously evaluating countries' economic, commercial, logistical, and sectoral indicators to generate strategic insights. This doctoral dissertation, titled "The Use of Decision Support Systems in the Process of Export Market Selection," aims to evaluate market selection in the electrical-electronics, machinery, and automotive sectors of a Turkish export firm using AI-supported data analytics methods. The study integrates various indicators such as economic data from countries, bilateral sectoral trade statistics of countries with Türkiye, trade facilitation metrics, and logistics performance indicators into the analysis. In this context, artificial intelligence-based clustering analysis techniques such as Self-Organizing Maps (SOM) and k-means clustering were employed to group countries with similar characteristics. The export potential of each cluster was then evaluated through TOPSIS method. These analyses not only helped to identify potential export markets but also allowed for a comparison between Türkiye's current export performance and the clustering model results, thereby assessing the accuracy of the decision support systems. The findings of the study aim to demonstrate the advantages that AI-supported systems offer to companies in making faster and more accurate export decisions. The results are expected to contribute both to academic literature and to practitioners developing export strategies
Can triad forestry reconcile Europe's biodiversity and forestry strategies? A critical evaluation of forest zoning
Get PDFBalancing increasing demand for wood products while also maintaining forest biodiversity is a paramount challenge. Europe's Biodiversity and Forest Strategies for 2030 attempt to address this challenge. Together, they call for strict protection of 10% of land area, including all primary and old growth forests, increasing use of ecological forestry, and less reliance on monocultural plantations. Using data on country wide silvicultural practices and a new database on strict forest reserves across Europe, we assess how triad forest zoning could help meet these goals. Our analysis reveals that zoning in Europe is overwhelmingly focused on wood production, while there has been little concomitant protection of forests in strict reserves. Moreover, most strict forest reserves are < 50 ha in size, likely too small to capture the minimum dynamic area necessary to sustain many taxa. We outline research priorities to meet future demands for timber while minimizing the impact on native biodiversity.COST (European Cooperation in Science and Technology) [CA18207]Slovenian Research and Innovation Agency core funding (ARiS) [P4-0059]Pahernik foundationCzech Science Foundation [GACR 22-31322S]This study was based upon work from COST Action CA18207, supported by COST (European Cooperation in Science and Technology). T. Nagel received additional support from the Slovenian Research and Innovation Agency core funding (ARiS, P4-0059) and the Pahernik foundation. M. Mikolas and J. Hofmeister were supported by the Czech Science Foundation (grant GACR 22-31322S). We thank Claudia Steinacker and Falko Engel for compiling data and providing explanations of strict forest reserves in Germany. We also thank A. Balmford, M. Betts, and G.R. Cerullo for comments on a previous version of the manuscript
Investigation of material extrusion parameters and printing material impacts on wear and friction using the Taguchi method
Get PDFPurposeThe purpose of this study is to find optimum production parameters using the Taguchi method in terms of printing material (a composite material produced from polylactic acid [PLA] and polypropylene [PP]) impacts on wear and friction.Design/methodology/approachA composite filament coil was fabricated from PLA and PP pellets using a lab-based extrusion device. The hardness and chemical structure of the filaments were examined. The filament-based material extrusion process was used to produce cylindrical shapes for tribological (pin-on-disc) analyses. Moreover, Taguchi methodology was performed to find the most influential parameter on tribological characteristics.FindingsThe hardness (Shore D) values of the filaments were polylactic acid (PLA) (85), polypropylene (PP) (58) and PLA and PP mixture of 50:50 (PLAPP) (63). Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis results show that PLA and PP mixtured successfully. The diameter deviation of all samples was found as lower than 5%. The honeycomb pattern presented the best dimensional accuracy. Changing printing patterns and temperatures affect the friction profile. Coefficient of friction (COF) values of cylindrical samples of PLA and PP samples around 0.35 and 0.31, respectively. Overall, material type for wear resistance applications is a key point.Originality/valueTo the best of the author's knowledge, there seems to be a lack of 3D-printed PP and PLAPP studied in terms of tribological aspects as a neat polymer. The tribological profiles of PP, PLA and PLAPP (PLA and PP mixture of 50:50) were investigated in this study. The author believe that this is a preliminary study that might close the gap and add some novel information to the current literature
Reshaping School Cultures: AI's Influence on Organizational Dynamics and Leadership Behaviors
Get PDFThis research explores the integration of artificial intelligence (AI) into the educational processes at Hisar Schools, a leading educational institution in Turkey. By examining the strategic implementation of AI, this research highlights how AI enhances personalized learning, supports differentiated instruction, and streamlines administrative tasks. The study also delves into the role of school leadership in fostering a culture of innovation and the impact of AI on students, educators, administrators, and the broader community. Through a single case study methodology, the research provides detailed insights into the proactive approaches and policies that make Hisar Schools a pioneer in AI integration in education
Investigation of Electromagnetic Shielding Performance of Monolayer Ironboride in Tetragonal Crystal Structure using Ab initio Methods
Get PDFThe negative effects of pollution caused by electromagnetic radiation on human health and sensitive systems have reached serious dimensions. The most effective way to deal with this pollution is to create isolated areas with shielding materials. Especially after the discovery of graphene, studies on 2D materials continue to reveal the extraordinary structural, electronic and optical properties of 2D materials. Thanks to the research on the use of monolayer materials in electromagnetic shielding, ultra-thin and high-performance shielding materials are being obtained. In this study, the electromagnetic radiation shielding efficiency (SE) of a 2D film-structured material with a tetragonal crystal structure in the MBene class of the MXene family and obtained using Fe2B unit cells in the P4/mmm space group has been investigated using ab-initio methods. The electrical, optic and magnetic behavior of the material in the ground state is determined using the density functional theory (DFT) approach. The Curie temperature was investigated using the Monte Carlo method. The shielding efficiency of Fe2B has been investigated in the range of 31.558-123980 nm of the electromagnetic wave spectrum at [001], [010], [100] polarization states. Despite Fe2B 2D monolayer film structure, it showed a shielding performance (SET) of >20 dB. This study shows that Fe2B in film structure is a promising and exciting material for ultra-thin shielding material applications with its superior shielding performance at nanometer dimensions