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Master Thesis Optoelektronik Malzemelerin Analizi(2017) Alqurqash, Ayoob Yousıf Ahmed; Eseller, Kemal EfeOptoelektronik, ışığın yayılımı ve algılanması LED'lerin, güneş pillerinin, transistörlerin, ve fotodetektörlerin yapısı ve üretimi ile ilgili olan bir anabilim dalıdr. Cihazların sentezlenmesinde kullanılan malzemeler, (Silikon, MWCNT, SWCNT ve Grafen) radyasyon ışığını elektriğe veya tersine dönüştürme kapasitesine göre değişim göstermektedir. Bu tez, optoelektronik sistemlerde özellikle karbondan (grafit, fulleren, CNT, MWCNT, SWCNT ve Grafen) üretilen malzemelerin kökenini temsil eden grafen materyalinde bulunan karbon nanotüp malzemelerin analizini incelemekte ve MWCNT'lerin istisnai özelliklerini vurgulamaktadır. MWCNT numunesi üzerindeki deneyler, güç lazeri (200mW, 100mW, 50mW) ve dalga boyu 532nm olan Raman spektrometresi kullanılarak gerçekleştirilmiştir.Article Citation - WoS: 3Citation - Scopus: 3Classification of Different Recycled Rubber-Epoxy Composite Based on Their Hardness Using Laser-Induced Breakdown Spectroscopy (libs) With Comparison Machine Learning Algorithms(Mdpi, 2023) Yilmaz, Vadi Su; Yılmaz, Vadi Su; Eseller, Kemal Efe; Aslan, Ozgur; Aslan, Özgür; Bayraktar, Emin; Eseller, Kemal Efe; Yılmaz, Vadi Su; Aslan, Özgür; Eseller, Kemal Efe; Electrical-Electronics Engineering; Department of Electrical & Electronics Engineering; Mechanical Engineering; Electrical-Electronics Engineering; Mechanical Engineering; Department of Electrical & Electronics EngineeringThis paper aims toward the successful detection of harmful materials in a substance by integrating machine learning (ML) into laser-induced breakdown spectroscopy (LIBS). LIBS is used to distinguish five different synthetic polymers where eight different heavy material contents are also detected by LIBS. Each material intensity-wavelength graph is obtained and the dataset is constructed for classification by a machine learning (ML) algorithm. Seven popular machine learning algorithms are applied to the dataset which include eight different substances with their wavelength-intensity value. Machine learning algorithms are used to train the dataset, results are discussed and which classification algorithm is appropriate for this dataset is determined.Article Citation - WoS: 86Citation - Scopus: 103Determination of Whey Adulteration in Milk Powder by Using Laser Induced Breakdown Spectroscopy(Elsevier Sci Ltd, 2016) Bilge, Gonca; Sezer, Banu; Eseller, Kemal Efe; Berberoglu, Halil; Topcu, Ali; Boyaci, Ismail HakkiA rapid and in situ method has been developed to detect and quantify adulterated milk powder through adding whey powder by using laser induced breakdown spectroscopy (LIBS). The methodology is based on elemental composition differences between milk and whey products. Milk powder, sweet and acid whey powders were produced as standard samples, and milk powder was adulterated with whey powders. Based on LIBS spectra of standard samples and commercial products, species was identified using principle component analysis (PCA) method, and discrimination rate of milk and whey powders was found as 80.5%. Calibration curves were obtained with partial least squares regression (PLS). Correlation coefficient (R-2) and limit of detection (LOD) values were 0.981 and 1.55% for adulteration with sweet whey powder, and 0.985 and 0.55% for adulteration with acid whey powder, respectively. The results were found to be consistent with the data from inductively coupled plasma-mass spectrometer (ICP-MS) method. (C) 2016 Elsevier Ltd. All rights reserved.Article Citation - Scopus: 1Performance Evaluation of Self-Mixing Interferometer With the Ceramic Type Piezoelectric Accelerometers(de Gruyter Poland Sp Z O O, 2022) Berberoglu, Halil; Tiken, Mehmet; Eseller, Kemal Efe; Orhan, Elif; Candan, CanIn this article, reconstructed displacement from the self-mixing signal is compared with the displacement obtained by the ceramic shear mode design piezoelectric accelerometer. Piezoelectric accelerometers are widely accepted due to the low output noise and wide frequency range, but nevertheless it is not contact-free. Self-mixing interferometric signals due to the vibrating target on which an accelerometer is attached are acquired by an external silicon type photodetector. The laser light hits directly the accelerometer as a target which is driven by the sum of two different sinusoidal frequencies of 150 and 300 Hz with different voltage levels.Article Citation - WoS: 115Citation - Scopus: 138Identification of Meat Species by Using Laser-Induced Breakdown Spectroscopy(Elsevier Sci Ltd, 2016) Bilge, Gonca; Velioglu, Hasan Murat; Sezer, Banu; Eseller, Kemal Efe; Boyaci, Ismail HakkiThe aim of the present study is to identify meat speciesby using laser-induced breakdown spectroscopy (LIBS). Elemental composition differences between meat species were used for meat identification. For this purpose, certain amounts of pork, beef and chicken were collected from different sources and prepared as pellet form for LIBS measurements. The obtained LIBS spectra were evaluated with some chemometric methods, and meat species were qualitatively discriminated with principal component analysis (PCA) method with 83.37% ratio. Pork beef and chicken-beef meat mixtures were also analyzed with partial least square (PLS) method quantitatively. Determination coefficient (R-2) and limit of detection (LOD) values were found as 0.994 and 4.4% for pork adulterated beef, and 0.999 and 2.0% for chicken adulterated beef, respectively. In the light of the findings, it was seen that LIBS can be a valuable tool for quality control measurements of meat as a routine method. (C) 2016 Elsevier Ltd. All rights reserved.Article Citation - WoS: 27Citation - Scopus: 36Determination of Ca Addition To the Wheat Flour by Using Laser-Induced Breakdown Spectroscopy (libs)(Springer, 2016) Bilge, Gonca; Sezer, Banu; Eseller, Kemal Efe; Berberoglu, Halil; Koksel, Hamit; Boyaci, Ismail HakkiThe aim of the study was to determine Ca addition to the flour by using laser-induced breakdown spectroscopy (LIBS) as a quick and simple multi-elemental spectroscopy method. Different amounts of CaCO3-added wheat flour were analyzed using LIBS to determine Ca content and Ca/K ratio, which is used for discrimination of natural and Ca-added flour. LIBS spectra were quantitatively evaluated with partial least square (PLS) method as a multivariate data analysis method to eliminate the matrix effect. Ca and Ca/K calibration graphs of PLS method showed good linearity with coefficient of determinations (R (2)) 0.999. Limit of detection values for Ca and Ca/K analysis were calculated as 25.9 ppm and 0.013, respectively. Furthermore, the results were found to be consistent with the data obtained from atomic absorption spectroscopy method as a reference method for flour samples.Article Citation - WoS: 5Citation - Scopus: 6Blood Metal Analysis of Plasmas From Donors With and Without Sars-Cov Using Laser-Induced Breakdown Spectroscopy and Logistic Regression(Optica Publishing Group, 2024) Melikechi, Noureddine; Adler, Helmar G.; Safi, Ali; Landis, Joshua E.; Pourkamali-Anaraki, Farhad; Eseller, Kemal Efe; Xia, Weiming; Efe Eseller, KemalResearch on the correlation between metal levels in blood and Covid-19 infection has been conducted primarily by assessing how each individual blood metal is linked to different aspects of the disease using samples from donors with various levels of severity to Covid-19 infection. Using logistics regression on LIBS spectra of plasma samples collected pre- and postCovid-19 pandemic from donors known to have developed various levels of antibodies to the SARS-Cov-2 virus, we show that relying on the levels of Na, K, and Mg together is more efficient at differentiating the two types of plasma samples than any single blood alone.Article Citation - WoS: 15Citation - Scopus: 17Performance Evaluation of Laser Induced Breakdown Spectroscopy in the Measurement of Liquid and Solid Samples(Pergamon-elsevier Science Ltd, 2018) Bilge, Gonca; Sezer, Banu; Boyaci, Ismail Hakki; Eseller, Kemal Efe; Berberoglu, HalilLiquid analysis by using LIBS is a complicated process due to difficulties encountered during the collection of light and formation of plasma in liquid. To avoid these, some applications are performed such as aerosol formation and transforming liquid into solid state. However, performance of LIBS in liquid samples still remains a challenging issue. In this study, performance evaluation of LIBS and parameter optimizations in liquid and solid phase samples were performed. For this purpose,milk was chosen as model sample; milk powder was used as solid sample, and milk was used as liquid sample in the experiments. Different experimental setups have been constructed for each sampling technique, and optimizations were performed to determine suitable parameters such as delay time, laser energy, repetition rate and speed of rotary table for solid sampling technique,and flow rate of carrier gas for liquid sampling technique. Target element was determined as Ca, which is a critically important element in milk for determining its nutritional value and Ca addition. In optimum parameters, limit of detection (LOD), limit of quantification (LOQ) and relative standard deviation (RSD) values were calculated as 0.11%, 0.36% and 8.29% respectively for milk powders samples; while LOD, LOQ and RSD values were calculated as 0.24%, 0.81%, and 10.93% respectively for milk samples. It can be said that LIBS is an applicable method in both liquid and solid samples with suitable systems and parameters. However, liquid analysis requires much more developed systems for more accurate results. (C) 2018 Elsevier B.V.All rights reserved.Article Citation - WoS: 54Citation - Scopus: 68Analysis of Bakery Products by Laser-Induced Breakdown Spectroscopy(Elsevier Sci Ltd, 2015) Bilge, Gonca; Boyaci, Ismail Hakki; Eseller, Kemal Efe; Tamer, Ugur; Cakir, SerhatIn this study, we focused on the detection of Na in bakery products by using laser-induced breakdown spectroscopy (LIBS) as a quick and simple method. LIBS experiments were performed to examine the Na at 589 nm to quantify NaCl. A series of standard bread sample pellets containing various concentrations of NaCl (0.025-3.5%) were used to construct the calibration curves and to determine the detection limits of the measurements. Calibration graphs were drawn to indicate functions of NaCl and Na concentrations, which showed good linearity in the range of 0.025-3.5% NaCl and 0.01-1.4% Na concentrations with correlation coefficients (R-2) values greater than 0.98 and 0.96. The obtained detection limits for NaCl and Na were 175 and 69 ppm, respectively. Performed experimental studies showed that LIBS is a convenient method for commercial bakery products to quantify NaCl concentrations as a rapid and in situ technique. (C) 2015 Elsevier Ltd. All rights reserved.Master Thesis Ankara'da Uzak Komünite için Sıfır Enerji Binalarında Bağımsız Mikrogrıd Hibrit Enerji Sisteminin Techno-ekonomik Optimizasyonu(2020) Hayalı, Othman Jasım Mohammed Al; Mehrtash, Mehdi; Eseller, Kemal EfeArtan elektrik enerji tüketimi, fosil yakıtların azalması, iletim hatlarının yüksek fiyatları ve çevre kirliliği sorunları ülkeleri yenilenebilir enerji kaynaklarından elektriğin üretildiği sıfır enerji binaları (ZEB) geliştirmeye itmektedir. Rüzgar ve güneş enerjileri ümit verici kaynaklardır. Ancak, bu kaynakların kesintili doğası sistem güvenilirliğini azaltır. Hibrid yenilenebilir enerji sistemi (HRES), bu soruna bir çözüm olarak kabul edilir. Bir HRES tasarlamak için yatırımcıların minimum yapılandırma maliyetini göz önünde bulundurmaları gerekir. Bu çalışmada, Ankara'da uzak bir bölgede 30 evin elektriklendirmek için fotovoltaik (PV) ve rüzgar türbini (WT) sistemlerinin kurulması simüle edilmiştir. Yükü en az maliyetle karşılayabilecek en uygun hibrit sistemi elde etmek için farklı senaryolar düşünülmüştür. Optimal konfigürasyon elde etmek için Çoklu Enerji Kaynakları için Hibrid Optimizasyon Modeli (HOMER) yazılımı ve Parçacık Sürüsü Optimizasyonu (PSO) algoritması uygulanmıştır. 107 kW PV, 3 × 10 kW WT, 10 kW dizel jeneratör (DG) ve 45 × 7.15 kWh pillerden oluşan HRES, elektrik yükü talebini karşılamak için en uygun seçim olarak seçilmiştir. Enerji maliyeti (COE) ve net yüzde maliyeti (NPC) sırasıyla 0.25 $/kWh ve 568431 $ olarak bulunmuştur. Duyarlılık analizinde sonuçları doğrulamak için PV ve WT sermaye maliyetlerinin, yakıt fiyatının ve pillerin türünün sistem performansı üzerindeki etkileri incelenmiştir. Sonuç olarak, yakıt fiyatını ikiye katlamak, COE ve NPC'yi sırasıyla 14% ve 13% oranında arttırdıgı gözlenmiştir. PV ve WT sermaye maliyetleri yarıya düştüğünde, COE ve NPC sırasıyla 20% ve 12% oranında azalmıştır. Belirli bir pil teknolojisinin kullanılmasının hem genel fiyatı hem de gaz emisyonlarını azalttığı görülmüştür. Anahtar Kelimeler: Off-grid ZEB, Yenilenebilir Enerji, PSO, HOMER, Ankara
