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Öğe Developing a guideline for color designing suitable to autonomous vehicles(Ege Üniversitesi, 2023) Uzunkavak, Onur; Özdemir, GünseliBu çalışma, araç özerkliğinin talep edildiği otomotiv endüstrisi için renk tasarımlarını ele almaktadır. LiDAR (Işık Algılama ve Mesafe Belirleme) teknolojisi nesneleri algılama, sınıflandırma ve tanıma, güvenli ve verimli sürüş kararları verme konusunda çeşitli teknolojiler arasında en iyi alternatif olarak gösterilmektedir. LiDAR üniteleri çevreye yaydığı 905nm dalgaboyundaki yakın kızılötesi (NIR) ışığın çevredeki yüzeylerden yansıyan kısmını algılar. Bu çalışma ile LiDAR ile saptanabilen otomotiv sonkatlarına renk vermek için fonksiyonel pigmentlerin akrilik dispersiyonları formüle edilmiştir. Dispersiyon işlemi öncesinde fonksiyonel pigmentlerin tanecik yüzey yükleri kalitatif olarak belirlenmiş, bu doğrultuda uygun ıslatıcı ajan seçimi yapılmıştır. Pigment dispersiyonlarının stabilitesi doğrulandıktan sonra belirli miktarlarda kullanılan dispersiyonlar ile, 35µm sonkat kuru film kalınlığında opaklık elde edilecek şekilde RAL 841-GL renk kartelasındaki RAL 9011 (Grafit siyahı), RAL 5017 (Trafik mavisi) ve RAL 5015 (Gök mavisi) konvansiyonel boyalarla aynı renk LiDAR-saptanabilir yenilikçi boyalar formüle edilmiştir. Pnömatik sprey uygulanabilirliklerini desteklemek amacıyla konvansiyonel ve yenilikçi yaş boyaların akış karakteristikleri karşılaştırılmıştır. Çelik yüzey üzerine beyaz epoksi astar ve akrilik sonkattan oluşan kaplama gamı için renk, parlaklık, pusluluk ve görüntü belirginliği değerleri incelenmiştir. Yenilikçi kaplamaların toplam renk farkı RAL 9011, RAL 5017 ve RAL 5015 için sırasıyla 0,11, 0,52 ve 0,26 olarak sonuçlanmış, UV-Vis-NIR spektrumları analiz edildiğinde yenilikçi kaplamalarla her üç renk için de 905nm dalgaboyunda yansıtıcılık artışı gözlenmiştir. LiDAR ünitesine normal, normal açıya göre 10° ve 35° açılarda, LiDAR ünitesinin 200m ilerisine konumlandırılan kaplamalar ile oval araç yüzeyleri de simüle edilerek uzun menzilli ölçümler yapılmış, yenilikçi kaplamaların üstün LiDAR saptanabilirliği ile çalışma amacına ulaşılmıştır. Anahtar sözcükler: pigment dispersiyonu, akrilik sonkat boyalar, renk eşleme, LiDAR saptamaÖğe Development of near-infrared reflective inorganic pigment dispersions in the continuous phase of solvent-binder medium(Springer, 2024) Uzunkavak, Onur; Ozdemir, GunseliCoatings containing functional pigments capable of reflecting radiation in the near-infrared (NIR) spectrum have been coveted in recent years to meet various industrial specifications. In this study, NIR reflective inorganic pigments with the chemical structure of TiO2, CoAl2O4, and (Cr,Fe)2O3 were dispersed individually in the continuous phase of organic solvents and thermosetting acrylic polyol to form ready-to-use colorants for NIR reflective coatings. A total of ten different pigments, three TiO2, three CoAl2O4, and four (Cr,Fe)2O3, were included. Resin-dispersant compatibility and solvent-pigment compatibility in potential paint formulations were tested prior to dispersion design. The ability of the developed pigment dispersions to maintain the primary particle size distributions was confirmed by stability tests, and UV-Vis-NIR spectra of fresh pigment dispersions drawn-down on steel plates were comparatively evaluated. Although the change in pigment particle size distribution after subjecting the dispersions to different temperatures was negligible, the favorable NIR reflectance obtained by certain pigment dispersions served to select the optimum pigment dispersions within dispersions of the same pigment chemistry. The ALTIRIS 800, 22-5600, and 30C941 dispersions exhibited higher reflectance in the NIR spectrum compared to other developed TiO2, CoAl2O4, and (Cr,Fe)2O3 dispersions, respectively, and supported their use in paint designs suitable to autonomous vehicles.Öğe Modeling of single and binary adsorption of lead and cadmium ions onto modified olive pomace(Desalination Publ, 2019) Uzunkavak, Onur; Patterer, Maria Silvina; Medici, Franco; Ozdemir, GunseliThis study deals with the evaluation of the single and binary removal of Pb2+ and Cd2+ from aqueous solutions using HNO3 modified olive pomace (N-OP). For the specific binary adsorption behavior, a renovative isotherm model was developed based on the additivity of the single adsorption contributions of Pb2+ and Cd2+ calculated from the binary data. The effect of the initial metal ion concentration, pH, ionic strength, and temperature on the adsorption of the single Pb2+ and Cd2+, and their binary adsorption were investigated using batch experiments at the optimum conditions. The N-OP displayed maximum adsorption capacities of 64 mg g(-1) for Pb2+ and 20.5 mg g(-1) for Cd2+ from the single metal ion solutions using 1.0 g L-1 N-OP. The results were best fitted with the Langmuir model for Pb2+ and the Radke-Prausnitz model for Cd2+ adsorption at 25 degrees C. The reusability of the N-OP was confirmed with desorption studies. The thermodynamic study revealed that the adsorption of Pb2+ was exothermic and that of Cd2+ was an endothermic process. The existence of Cd2+ in a binary solution increased the Pb2+ removal while that of Pb2+ reduced the Cd2+ removal with N-OP. This behavior may contribute to a selective removal of the heavy metal ions from their mixture.Öğe Removal of heavy metal ions from aqueous solutions by chemically modified biosorbents(Ege Üniversitesi, Fen Bilimleri Enstitüsü, 2018) Uzunkavak, Onur; Özdemir, GünseliPresent study deals with the evaluation of single and binary adsorption of lead and cadmium ions from their aqueous solutions using olive pomace as a biosorbent. Olive pomace was modified with several chemicals and best results were obtained by nitric acid modification. Batch-wise experiments were conducted with raw (R-OP) and nitric acid modified olive pomace (N-OP). Process parameters were investigated. Binary adsorption of lead and cadmium ions onto N-OP was studied varying the initial heavy metal ion concentration ratios. Regenerative and reusable properties of N-OP were confirmed by consecutive adsorption-desorption cycles. Temperature study indicated that the adsorption process is feasible and spontaneous. Adsorbent characterization was accomplished by ATR-FTIR, SEM, and BET analyses. Surface charge and chemical content of adsorbents were determined by point of zero charge measurement and Van Soest method. Surface functional groups were characterized by Boehm titration method. Kinetic study revealed that lead and cadmium adsorption followed a pseudo-second-order model. Lead and cadmium uptake were enhanced by nitric acid modification from 33 mg/g to 64 mg/g and 8 mg/g to 20.5 mg/g, respectively, using 1 g/L N-OP at the optimum pH of 5.5 for lead ions and that of 6 for cadmium ions. Redlich-Peterson and Langmuir isotherms were the best fitting models for lead adsorption onto R-OP and N-OP, respectively. However, Langmuir-Freundlich and Radke-Prausnitz models were superior in cadmium adsorption onto R-OP and N-OP, respectively. The prevalence of lead adsorption was specified by the binary system investigation. A modified version of Radke-Prausnitz and Freundlich models showed the best fitting for concomitant presence of lead and cadmium ions in binary mixture, whereas a modified version of Dubinin-Raduskevich and Freundlich models showed the best fitting for constant background concentration of cadmium ion systems.
