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Innovative Hybrid Coatings: Uniting Boron Carbide and Graphite for Enhanced Performance in Electroless Nickel Boron Coating Process
No full textIn this study, two different powders were harmonized to develop electroless nickel-boron coatings with enhanced hardness and wear resistance. For this purpose, a new hybrid electroless nickel boron composite coating process was developed by using two different characteristic particles which are i) boron carbide and ii) graphite. The surface analysis showed that harmonizing two particles into one single coating bath exhibited good tribological and mechanical properties as compared to conventional single-particle composite and non-composite electroless nickel boron coatings. After the coating process, two different heat treatment procedures were carried out which are i) 250 degrees C-5 hours and ii) 400 degrees C-1 hour. Chemical composition, crystal structures, microhardness, tribological, and corrosion behaviors of the coatings were investigated. The comprehensive results showed the dual effect of different particles which have different characteristics lubricious and abrasive on hardness and tribological properties. The heat treatment process had also a positive effect on the tribological behavior of the hybrid composite coatings. Microhardness values of the hybrid composite coating improved by around 24-37% compared to electroless nickel boron coating alone whereas heat treatment processes led to an increment in hardness of around 50-87%. Besides it was observed that wear rates were 79-93% lower than classic nickel boron coating while heat treatment also decreased the wear rate by 154-165%. The corrosion resistance of the hybrid coating is similar to electroless nickel boron coating however it decreases slightly after the heat treatment process. Overall, the hybrid electroless nickel boron composites were successfully achieved and provide promising features for the coating employed in industrial applications.The authors would like to thank The Scientific and Technological Research Council of Turkiye (TUBITAK) for financial support (Project Number: 7220070) .Scientific and Technological Research Council of Turkiye (TUBITAK) [7220070
The Role of Mineralogical and Textural Complexity in the Damage Evolution of Brittle Rocks (Vol 14,28641,2024)
No full textThis research was financially supported by the Scientific and Technological Research Council of Turkey (TUB ; Idot;TAK) under Project Grant 121Y031. We gratefully acknowledge Prof. Kamil Kayabal ; imath; and the Rock Mechanics Laboratory at Ankara University for providing the rock samples used in this paper"Scientific and Technological Research Council of Turkey (TUBIdot;TAK) [121Y031
Re-Mapping of the Kilistra Ignimbrites Using Remote Sensing Methods and Gis-Based Lineament Analysis of the Beyşehir Basin (Sw Konya/Türkiye)
No full textRemote sensing (RS) and geographic information systems (GIS), which have a wide range of uses in geosciences, are used extensively in geological mapping (or updating), determining the boundaries of different lithologies, and detecting of tectonic discontinuities. The Bey ; scedil;ehir Basin has been selected as a plot area due to its geological diversity and tectonic characteristics in this study. Thus, "principal component analysis (PCA)" and "map classification" techniques were applied to Landsat-8 OLI satellite images by using remote sensing methods and re-mapping of the Kilistra ignimbrites extending in the northwest- southeast direction on the eastern slope of the Erenlerda ; gbreve;-Alacada ; gbreve; Volcanic Complex (ErAVC) (SW Konya/T ; uuml;rkiye). The methods of a practical application in details that will facilitate geological mapping and field studies of ignimbrites, which are characterized by quite complex settlement dynamics, are presented in this study. Additionally, to better understand the tectonic development of this basin, where Mio-Pliocene aged fluvial-lacustrine sediments and volcanics (ErAVC) are located, lineament analysis was applied by using GIS methods on the morpho-tectonic structures in the region. The results showed that a direct relationship between the forces shaping the area's morphology and tectonic movements in the region. As a result of these analyses, and according to their kinematics are; the tectonic stress and dominant faulting (dip-slip normal faults) directions shaping the Bey ; scedil;ehir Basin have been determined as NW-SE and NE-SW
Comprehensive Evaluation of Pm (Deposition/Tsp) Pollution From Multiple Quarrying Activities
No full textThis study, for the first time, analyzed organic matter (OM)-ash fractions, inorganic/organic species, chemical structures, and inhibition effects (EI) in the same sample using a novel procedure. This allowed for an evaluation of the actual contributions of these species to particulate matter (PM) and environmental impacts. Results showed that the mobilities of Al, Co, and potentially toxic elements (PTEs) (As, Cd, Cr, Cu, Pb, and Ni) varied between organic and inorganic phases depending on pH and organic groups. The transition of these elements into the organic phase, along with Ca, contributed to silica polymerization, increased EI in the organic eluate, and enhanced bioavailability in the presence of low water-soluble OM (WOM). Therefore, although Ca abundance reduced EI in the organic eluate, the organic eluate of multiple quarrying areas (MQA), with the lowest OM, exhibited an EI equivalent to the background area (BA). Although Sigma PTEs in total suspended particulates (TSP) inorganic eluates decreased compared to total deposition (TD), EI increased. Due to TD-facilitated accumulation-transition and metabolite formation, leading to higher EI in organic eluates. This finding aligned with similar effects observed in aged atmospheric aerosols from the same region. MQA activities significantly contributed to inert dust pollution, Ca, Cu, Cr, 40K, and Na accumulation, silica and alkali oxide abundance, SOA precursor (e.g., phthalic acid) transformation into more hazardous phthalate esters (PAEs), and new metabolite formation affecting climate change. These activities increased yearly TD and estimated mean TSP by 42 and 41 times, respectively, to 52.9 g/m2-year and 1.3 mg/m3 compared to BA. Despite MQA having the highest TSP-TD, semirural (SRRA) PM influenced by MQA exhibited the highest chemical composition and acute EI. Furthermore, it was found that, aside from Na and Se, there were no significantly enriched elements in MQA when compared to BA.The authors would like to acknowledge the financial support of the Konya Technical University Scientific Research Fund (KTUN-BAP) for the research described in this paper (Grant Numbers: 221001048).Konya Teknik Universitesi [221001048]; Konya Technical University Scientific Research Fund (KTUN-BAP
Investigation and Calculation of Electrical Performance of Lead-Free Agbii4 Perovskite Based Schottky Photodiode Using Machine Learning
No full textLead-free nanoparticles gain importance due to their environmentally clean and reliable production processes in optoelectronics. In this study, we synthesized AgBiI4 lead-free perovskite material and used it as an interlayer to obtain a Schottky photodiode structure. Optical, morphological, and structural properties were investigated via UV-Vis, SEM, SEM-EDS, AFM, and XRD. The crystal structure was confirmed by X-ray diffraction (XRD) results. The results obtained from the UV-Visible spectrophotometer clearly showed the peaks of the crystal structure at 566.94 nm. The band gap calculated from UV-Vis results was 1.91 eV for AgBiI4 perovskite crystals. We used AgBiI4 structures as interlayers between n-type Si and Al to obtain a photodiode heterostructure and investigate their structural sensing performance using current-voltage and current-transient measurements. Ideality factor and barrier height values were calculated using machine learning. Lead-free perovskite structures recorded excellent photodetector properties, reaching 2.636 A/W responsivity and 1.30 x 1011 Jones detectivity.This study was the part of the PhD study of Emre Unver. This study was financially supported by Scientific Research Projects Coordination Unit of Konya Technical University under the project number of 241116024.Scientific Research Projects Coordination Unit of Konya Technical University [241116024
Kompozit Malzemelerde Şeker Üretimi Atıklarının Değerlendirilmesi
No full textOne of these is the waste material of sugar factories, pulp and carbonation sludge (CC), and their evaluation in different products will also help solve the environmental problem. In this study, sugar production wastes as filler material: calcium carbonate waste, which is the calcination stage sediment, and sugar beet pulp were used to prepare composite materials and evaluated in composite production. Phenolic epoxy resin (FER) was used as a matrix in the preparation of composites, and anhydride and amine-type compounds were used as 2 different curatives. The effects of different fillers and curing agents on the mechanical and thermal properties of the composites were investigated. The morphological structures of the composites were characterized by scanning electron microscopy (SEM), and their thermal properties were characterized by TGA. Tensile and hardness tests were applied to determine the mechanical properties. The most suitable filler ratio for both types of composites was determined as 20%. The highest tensile strength values were seen in CC composites. Similarly, KK composites exhibited higher thermal resistance. The tensile strengths of KK composites were found to be 96 MPa in the case of 20% filler ratio and MNA curing agent and 84 MPa in the case of KH 816 curing agent. The tensile strengths of bagasse composites were determined to be 79 MPa and 75 MPa in the case of 20% filler ratio and MNA and KH 816 curing agents, respectively.In the industry, unused waste materials emerge when raw materials are processed for a certain purpose.Endüstride ham maddeler belli bir amaca göre işlenirken geriye kullanılmayan atık maddeler ortaya yardımcı olacaktır. Bu çalışmada dolgu maddesi olarak şeker üretimi atıkları: kireçleme aşaması çökeltisi olan kalsiyum karbonat atığı ve şeker pancarı küspesi, kompozit malzemelerin hazırlanması için kullanılarak kompozit yapımında değerlendirilmiştir. Kompozitlerin hazırlanmasında fenolik epoksi reçine (FER) matris olarak, anhidrit ve amin türü bileşikler ise 2 farklı kürleştirici olarak kullanılmıştır. Kompozitlerin mekanik ve termal özelliklerine, farklı dolgu maddelerinin ve kürleştiricilerin etkisi incelenmiştir. Kompozitlerin morfolojik yapıları taramalı elektron mikroskobu (SEM) ile, termal özellikleri TGA ile karakterize edilmiştir. Mekanik özelliklerin belirlenmesinde çekme ve sertlik testleri uygulanmıştır. Her 2 tür kompozit için de en uygun dolgu oranı %20 olarak belirlenmiştir. En yüksek çekme dayanımı değerleri KK kompozitlerinde görülmüştür. Benzer şekilde, KK kompozitleri daha yüksek termal dayanım sergilemişlerdir. KK kompozitlerinin çekme dayanımları %20 dolgu oranı ve MNA kürleştiricisi durumunda 96 MPa, KH 816 kürleştiricisi durumunda ise 84 MPa olarak bulunmuştur. Küspe kompozitlerinin çekme dayanımları ise %20 dolgu oranında MNA ve KH 816 kürleştirileri durumunda sırasıyla 79 MPa ve 75 MPa olarak belirlenmiştirçıkmaktadır. Bunlardan biri de şeker fabrikalarının atık maddesi olan küspe ve karbonatlama çamuru (KK) atıklarıdır ve bunların farklı ürünlerde değerlendirilmesi çevre sorununun çözümüne de
The Effect of Case Hardening on the Natural Preservation of Stone Monuments, Fraktin Monument, Türkiye
No full textCase-hardening processes that develop in monuments reduce the porosity of rocks while increasing surface hardness. This situation may contribute to the transfer of cultural stone heritage markers to future generations by limiting the penetration into the rock structure of water, which is the most destructive agent in atmospheric weathering processes. This study focused on the Fraktin relief monument, which was created by the Hittites in the 13th century BCE by carving into the rock surface. The site was investigated to reveal the case-hardening mechanism and its effects on the physical properties of the rock. The geochemical formation mechanism of the surface-hardening process, which contributed to the survival of the Fraktin relief monument, was examined by use of scanning electron microscope-energy dispersive spectrometry (SEM-EDS) and analysis by an inductively coupled plasma-mass spectrometer (ICP-MS). In addition, the effect of the hardening on the physical properties of the rock was investigated with nondestructive tests applied both in situ and in a laboratory. The SEM-EDS and ICP-MS analyses revealed that amorphous silica filled the pores of the rock and created surface hardening. This situation has increased the geotechnical properties of the unit in which the monument was carved, making it more resistant to atmospheric processes.Open access funding provided by the Scientific and Technological Research Council of Turkiye (TUBITAK).Scientific and Technological Research Council of Turkiye (TUBITAK
Exploring the Viability of Low-Grade Turkish Clays in the Development of Limestone Calcined Clay Cement (lc3) and Mortars
No full textUnderstanding the variability in raw materials for limestone calcined clay cement (LC3) is crucial for developing standardized protocols and optimizing production for reliable performance. T ; uuml;rkiye, Europe's largest cement producer, has yet to see research focused on LC3 development using local resources. This study, for the first time, focuses on developing LC3 and mortars based on Turkish clays, aiming to address the challenges posed by the geographical variability of raw materials in LC3 research. To improve the sustainability credentials of LC3, abundant low-grade/waste clays from mine tailings (MT) and construction and demolition waste (CDW) were extensively investigated in paste and mortar forms. Each clay was individually analyzed for chemical composition, mineralogy, and physical characteristics through X-ray diffraction (XRD), X-ray Fluorescence (XRF), wet method, thermogravimetric (TG) analysis, and particle size distribution (PSD). Based on the hardness of the raw materials, bulk low-grade/waste-based clays, limestone, and gypsum were hybrid ground to improve particle size distribution and material homogeneity. The viscosity and plasticity of clays from MT and CDW were compared, considering their impact on grindability, consistency and flowability. The consistency, setting time, flowability, and compressive strength of LC3 mixtures were benchmarked against traditional CEM I cement pastes and mortars, as well as LC3 specimens made with high-grade refined kaolin. Life cycle analysis (LCA) was performed to quantify environmental impacts. Each LC3 mixture having low-grade/waste clays met the standards for consistency, setting time, and strength activity index. The results highlight the potential for broader use of lowgrade calcined clays and CDW from T ; uuml;rkiye as practical, sustainable, and competitive alternatives to traditional Portland cement/mortar, significantly reducing the environmental impact.The authors gratefully acknowledge the financial assistance of the Scientific and Technical Research Council of Turkiye (TUBITAK) for the project titled "Development of Limestone Calcined Clay Cement (LC 3) and Mortars with Low Quality Clays from Turkiye" and numbered "123M850". This publication is a part of the master thesis dissertation work by the first author in the Academic Program of Civil Engineering, Institute of Science, Konya Technical University supported by the Scientific Research Projects (BAP) Coordination Office under grant "231004022".Scientific and Technical Research Council of Turkiye (TUBITAK) [123M850]; Scientific Research Projects (BAP) Coordination Office [231004022
Kripto Para Ekosistemi ve Küresel Göstergelerin Bitcoin Fiyatı Üzerindeki Etkisi
No full textBu araştırma, Bitcoin’in fiyatını etkileyen faktörleri belirleyerek Bitcoin'in fiyatını tahmin etmeyi amaçlamaktadır. Çalışma, kripto para ekosistemiyle ilgili veriler ve önemli küresel endekslerle ilgili veriler olmak üzere toplamda 396 değişkeni bir araya getirmektedir. Analiz, Ekim 2022’den Aralık 2022’ye kadar olan 90 günlük bir veri setini kullanmaktadır. Veri seti, %85’i eğitim ve %15’i test için ayrılmıştır. 18 makine öğrenme yöntemi arasından en yüksek doğruluğa sahip olan model seçilmiştir. Bulgular, modelin, 0.909 R2 skoruyla iyi bir performans sergilediğini göstermektedir
Prematüre Yenidoğanlarda Vaka Önleme ve Yönetimi için Dijital İkiz
No full textPremature newborns are infants who are born before fully completing their developmental processes in the womb. These infants spend a critical period in the Neonatal Intensive Care Unit (NICU), where their growth and development are closely monitored. During this time, premature infants are highly susceptible to various medical conditions, making it essential to continuously track and record their medical parameters and laboratory findings. Some medical conditions can progress so rapidly that they might lead to the infant's death within hours after the onset. Therefore, early detection before the occurrence of such cases and developing strategies for effective case management are critically important. Digital twins represent physical objects or processes by transferring sensor data into a digital environment, creating virtual representations. Through digital twins, it is also possible to generate artificial scenarios to simulate real-life conditions. Artificial intelligence (AI) enhances digital twin models by enabling forward-looking predictions and inferences. In this thesis, laboratory findings, medical parameters, and hyperspectral images from 47 premature infants treated at Selçuk University's NICU were analyzed. All collected data, including images and parameters, were recorded with timestamps. Based on this data, AI models were developed for forecasting future CRP, bilirubin, and hemoglobin values through time series analyses using current and past medical parameters, as well as disease prediction using timestamped hyperspectral images. Long Short-Term Memory (LSTM), XGBoost, and LSTM-Multi-Head Attention (MHA) mechanisms were utilized to develop time series analysis models for predicting future laboratory findings. The LSTM-based time series analysis model achieved R-squared accuracies of 29.09% for CRP, 36.36% for bilirubin, and 46.63% for hemoglobin predictions. The XGBoost model obtained Mean Squared Errors (MSE) of 9.76 for bilirubin and 16.8 for hemoglobin predictions. Using the LSTM-MHA model, R-squared accuracies of 91.78%, 66.76%, and 77.62% were achieved for CRP, bilirubin, and hemoglobin, respectively. Additionally, a Hyperspectral Vision Transformer (HSViT) model was developed for disease prediction using timestamped hyperspectral imagery. Principal Component Analysis (PCA) was applied to the hypercube dataset at different levels 5, 50, and 100 components and models were trained on these reduced datasets. The best-performing model was trained on a dataset reduced to 50 principal components, achieving an accuracy of 98.92%, precision of 96.48%, sensitivity of 99.50%, and an F1-score of 97.95%. This thesis demonstrates that artificial intelligence models integrated with digital twins can effectively predict future medical parameters and diseases in premature newborns, providing a promising early-warning system for disease prevention and management.Yeni doğan prematüreler anne karnında gelişimini tamamlamadan dünyaya gelmektedir. Bu bebekler gelişimlerinin tamamlanması ve süreçlerinin izlenmesini Yenidoğan Yoğun Bakım Ünitesinde (YYBÜ) geçirmektedir. Bu süre içerisinde hastalıklara çok daha yatkın olan prematüreler için medikal parametreler ve laboratuvar bulguları sürekli olarak izlenmekte ve kayıt edilmektedir. Bazı vakalar ortaya çıktıktan birkaç saat sonrasında bebeğin ölümüyle sonuçlanabilecek kadar hızlı ilerlemektedir. Bu sebeple vaka ortaya çıkmadan önce tespit etmek ve vaka yönetimi için stratejiler geliştirilmesini sağlamak önem arz etmektedir. Dijital ikizler fiziksel bir nesnenin veya sürecin sensör değerlerinin dijital ortama aktarılmasıyla sanal bir temsilinin oluşturulmasıdır. Dijital ikizler ile yapay senaryolar üreterek gerçek hayat simülasyonları oluşturmak da mümkündür. Yapay zeka dijital ikiz modellerine ileriye yönelik tahminler ve çıkarımlar yapabilmesini sağlayan özellikler kazandırmaktadır. Bu tez çalışmasında Selçuk Üniversitesi YYBÜ'de kalan 47 prematüre bebekten elde edilen laboratuvar bulguları, medikal parametreler ve hiperspektral görüntüler ile çalışılmıştır. Alınan tüm görüntü ve parametreler zaman etiketli olarak kayıt edilmiştir. Bu veriler ile bebeklerin mevcut ve geçmiş medikal parametrelerine bakarak ileriye yönelik CRP, bilirubin ve hemoglobin değerlerini tahmin eden zaman seri analizleri ve zaman etiketli hiperspektral görüntüler ile hastalık tahmini yapan yapay zekâ modelleri geliştirilmiştir. Laboratuvar bulgularının ileriye yönelik tahmini için kullanılan zaman seri analizi modellerinin geliştirilmesinde LSTM, Xgboost ve LSTM-Çok Başlı Dikkat Mekanizması (ÇBD) yöntemlerinden faydalanılmıştır. LSTM sinir ağı ile geliştirilen zaman seri analizi modelinde %29.09 CRP, %36.36 bilirubin ve %46.63 R-Kare doğruluğuna erişilmiştir. Xgboost modellerinde bilirubin için 9.76, hemoglobin için 16.8 Ortalama Karesel Hata (OKH) değerine ulaşılmıştır. LSTM-ÇBD modelinde CRP, Bilirubin ve Hemoglobin değerleri için R-Kare doğruluğu sırasıyla %91.78, %66.76 ve %77.62 değerlerine ulaşmıştır. Hiperspektral Görü Dönüştürücü (HSViT) ile zaman etiketli hiperspektral görüntülerde hastalık tahmini yapan yapay zeka modeli geliştirilmiştir. Hiperküp veri kümesine 5, 50, 100 olmak üzere farklı seviyelerde Temel Bileşen Analizi (TBA) uygulanmış ve modeller bu veri setleri ile eğitilmiştir. En iyi model performansını %98.92 doğruluk, %96.48 kesinlik, %99.50 duyarlılık ve %97.95 F1-Skor ile 50 temel bileşene indirgenen veri seti ile eğitilen model göstermiştir. Bu tez çalışması ile yenidoğan prematürelerde dijital ikiz ile vaka önleme ve takibi için yapay zeka modelleri ile ileriye yönelik tahminlerin yapılabileceği ve bu tahminlerin hastalık teşhisinde bir erken uyarı sistemi olarak kullanılabileceği kanıtlanmıştır