Sürdürülebilir Yeşil Kampüs Koleksiyonu / Sustainable Green Campus Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7755
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Conference Object Citation - Scopus: 2Utilization of Near Ir Absorbing Gold Nanocolloids by Green Synthesis(Trans Tech Publications, 2018) Elveren, Beste; Yıldız, Ümit Hakan; Arslan Yıldız, AhuThe rapid developments in nanoscience, and its applications on biomedical areas have a large impact on drug delivery, tissue engineering, sensing, and diagnosis. Gold is widely investigated nanomaterial for the last couple of decades, since it has unique surface properties and very low toxicity to biological environment. In this work, we present a novel synthesis of gold nanoparticles (GNPs) exhibiting both visible and near-IR absorbance without agglomeration. The surface of GNPs were analyzed by routine methods and the binding kinetics were investigated by Surface Plasmon Resonance (SPR) Spectroscopy. The unique optical properties of near-IR asorbing GNP colloids hold promise for biological applications.Article Citation - WoS: 5Citation - Scopus: 5Tannery Wastewater Sediments Produced by Clinoptiolite/Polyacrylamide-aided Flocculation as a Clay Additive in Brick Making(Springer Verlag, 2017) Köseoğlu, Kemal; Cengizler, H.; İsrail, L. İ.; Polat, HürriyetToxic tannery wastewater(s) (TWW) pose(s) a great risk to the environment. This study explores the potential of mitigating the harmful effects of TWW through sedimentation using clinoptiolite in the presence of various anionic, cationic and non-ionic flocculants with different molecular weights and charge densities followed by encapsulation in a brick structure for stability. Compressive strength (CS), size reduction after firing (SRAF), water absorption (WA) and colouring parameters of bricks were determined. X-Ray diffraction (XRD) and scanning electron microscopy (SEM)-energy dispersive X-ray (EDX) analyses were conducted on brick bodies. Kinetic leaching experiments were conducted for possible heavy metal release from the bricks. Bricks containing 10 wt% leather waste and 5 wt% clinoptiolite sintered at 800 °C instead of 920 °C possessed similar properties to the standard brick (SB).Conference Object Üç Boyutlu Hücre Kültürü için Polimer Esaslı Ekstrasellüler Matriks Mimetiği(Institute of Electrical and Electronics Engineers Inc., 2017) Türker, Esra; Yıldız, Ümit Hakan; Arslan Yıldız, AhuElektro-eğirme metodu gelişmiş üretim teknolojilerindendir ve biyomedikal uygulamalarında yaygın olarak kullanılmaktadır. Özellikle doku mühendisliğinde amaç, çalışılacak doku üzerine doğal veya sentetik destek materyali (iskele) üreterek hücrenin uyum sağlayabileceği bir ortam oluşturmaktır. Bu projenin amacı üç boyutlu (3D) hücre kültürü çalışmaları için elektro-eğirme-metodu ile poli(L-laktik-co-epsilon-kaprolakton) (PLLCL) kullanılarak iskele üretilmesidir. Homojen lifler ve uygun gözenek boyutu elde etmek amacıyla optimizasyon çalışmaları yapılmıştır. Elde edilen liflerin çapı, akış hızı ve voltajın artmasıyla azalmaktadır. Taramalı uç elektron mikroskop incelemeleri (SEM) lif morfolojik yapılarının doku iskelesi fabrikasyonu için ideale yakın olduğunu ortaya çıkarmıştır.Article Citation - WoS: 62Citation - Scopus: 64Ultrasonic Nebulization-Sample Introduction System for Quantitative Analysis of Liquid Samples by Laser-Induced Breakdown Spectroscopy(Elsevier Ltd., 2012) Aras, Nadir; Ünal Yeşiller, Semira; Ateş Arıca, Dilek; Yalçın, ŞerifeIn this study, design and optimization studies of a sample introduction system based on ultrasonic nebulization of metal salts in aqueous environment for laser-induced breakdown spectroscopic detection were presented. The system consisted of an ultrasonic nebulizer connected to a tandem heater-condenser- membrane dryer unit that produces sub-micron size aerosols. Results indicate improvements in detection limits for some elements with the use of membrane dryer. Optimization studies were performed by systematical investigation of LIBS emission signal with respect to laser energy, carrier gas flow rate and detector timing parameters. Under optimized conditions, calibration graphs for Na, K, Mg, Ca, Cu, Al, Cr, Cd, Pb and Zn were constructed and detection limits were calculated. The applicability of the ultrasonic nebulization-LIBS system was tested on real water samples. This system establishes LIBS as an effective analytical tool for both qualitative and quantitative determination of metal aerosols in aqueous environments. This technique is sufficiently rapid to provide real-time monitoring of toxic metals.Article Citation - WoS: 23Citation - Scopus: 22Optimization of Chemical and Instrumental Parameters in Hydride Generation Laser-Induced Breakdown Spectrometry for the Determination of Arsenic, Antimony, Lead and Germanium in Aqueous Samples(Elsevier Ltd., 2013) Ünal Yeşiller, Semira; Yalçın, ŞerifeA laser induced breakdown spectrometry hyphenated with on-line continuous flow hydride generation sample introduction system, HG-LIBS, has been used for the determination of arsenic, antimony, lead and germanium in aqueous environments. Optimum chemical and instrumental parameters governing chemical hydride generation, laser plasma formation and detection were investigated for each element under argon and nitrogen atmosphere. Arsenic, antimony and germanium have presented strong enhancement in signal strength under argon atmosphere while lead has shown no sensitivity to ambient gas type. Detection limits of 1.1mgL-1, 1.0mgL-1, 1.3mgL-1 and 0.2mgL-1 were obtained for As, Sb, Pb and Ge, respectively. Up to 77 times enhancement in detection limit of Pb were obtained, compared to the result obtained from the direct analysis of liquids by LIBS. Applicability of the technique to real water samples was tested through spiking experiments and recoveries higher than 80% were obtained. Results demonstrate that, HG-LIBS approach is suitable for quantitative analysis of toxic elements and sufficiently fast for real time continuous monitoring in aqueous environments.Article Citation - WoS: 29Citation - Scopus: 38Encapsulating Fly Ash and Acidic Process Waste Water in Brick Structure(Elsevier Ltd., 2010) Köseoğlu, K.; Polat, Mehmet; Polat, HürriyetFly ash contains metals such as cadmium, iron, lead, aluminum and zinc in its structure in appreciable amounts. These metals can leach out into surface and ground waters if fly ash is not properly disposed of. A similar problem also exists for acidic process waste waters discharged by numerous industries. The purpose of this study was to utilize such wastes as additives in the production of construction quality bricks for the purpose of waste elimination. The bricks produced were subjected to flexural strength and water retention capacity tests along with heavy metal leaching experiments in order to determine the applicability of the procedure and the best possible recipes. This paper summarizes the results obtained in these tests along with the possible mechanisms involved in stabilizing the two wastes in the brick structure. © 2009 Elsevier B.V. All rights reserved.Conference Object Citation - WoS: 21Citation - Scopus: 21Development of a Continuous Flow Hydride Generation Laser-Induced Breakdown Spectroscopic System: Determination of Tin in Aqueous Environments(Elsevier Ltd., 2010) Ünal, Semira; Yalçın, ŞerifeThe design, construction and optimization studies of a continuous flow hydride generation laser-induced breakdown spectroscopic system, HG-LIBS, for the determination of tin in aqueous environments is presented. Optimization of the Laser Induced Breakdown Spectroscopy (LIBS) signal with respect to carrier gas flow rate, analyte, acid (HCl) and reductant (NaBH4) concentrations and flow rates was performed by using spectral emission intensity from the neutral Sn(I) line at 284.0 nm under atmospheric pressures. With flow rates of 5.0 mL/min for NaBH4 and 2.5 mL/min for HCl, optimum NaBH4 and HCl concentrations were determined as 2.0% (w/v) and 1.0% (v/v), respectively. The hydride generation efficiency of the system was tested for tin hydride, stannane (SnH4), by inductively coupled plasma mass spectrometer (ICP-MS). It was found that higher than 99% of the analyte was released into the gaseous phase. Upon optimization, the minimum detectable Sn concentration was found as 0.3 mg/L in water samples. That corresponds to more than two orders of increase in sensitivity compared to methods that employ common sample introduction techniques in liquids analysis by LIBS. Over 90% recoveries were obtained from spiking experiments with river, tap and drinking water samples. Results illustrate potential use of the continuous flow HG-LIBS system for monitoring of Sn concentrations in aqueous environments. © 2010 Elsevier Ltd. All rights reserved.Article Citation - WoS: 6Citation - Scopus: 8Growth and Uptake of Sodium and Potassium in Broad Bean (vicia Faba L.) Under Salinity Stress(Taylor and Francis Ltd., 2011) Bulut, Fatma; Akıncı, Şener; Eroğlu, Ahmet EminVicia faba L. (broad bean or faba bean), a food crop of worldwide importance, is moderately tolerant of saline conditions, such as are increasingly common in Mediterranean countries and in Turkey. Our objective was to determine the influence of two salinity levels [50 and 100 mM sodium chloride (NaCl)] and two potassium salts, potassium nitrate (KNO3) (N1 and N2) or potassium acetate (CH3COOK) (A1 and A2), on the development of seedlings of two cultivars of broad bean (cvs. Eresen 87 and Filiz 99) grown in pots of perlite under controlled greenhouse conditions. Flame photometer (FP) analysis of tissues from roots, stems, and leaves of 3-month-old seedlings showed significant differences in growth, internodal length, and potassium (K+)/sodium (Na+) ratios. The FP analyses revealed that Na+ was the ion most responsible for inhibition of growth parameters seen in both cultivars and salt treatments. K+ contents were consistently higher in cv. Filiz 99 than in cv. Eresen 87. Possible correlations between these data and the tolerance to salinity of these cultivars are discussed.Article Citation - WoS: 11Citation - Scopus: 15Effects of Humic Acid on Root Development and Nutrient Uptake of Vicia Faba L. (broad Bean) Seedlings Grown Under Aluminum Toxicity(Taylor and Francis Ltd., 2015) Büyükkeskin, Tamer; Akıncı, Şener; Eroğlu, Ahmet EminInteractions of humic acid with development and uptake by seedlings of Vicia faba L., (cv. Eresen 87) grown in conditions of aluminium toxicity have been investigated in pot experiments in a controlled greenhouse environment. The objective of the study was to investigate whether humic acid moderates aluminum toxicity. The seedlings were treated with solutions of aluminum chloride (AlCl3) prepared in Hoagland control nutrient solution (HO) and 50 and100 μM and humic acid + Hoagland (HA) solutions, respectively. The 50 and100 μM HA solutions increased root fresh (RFW) and dry (RDW) weights, where the RFW differed significantly from controls (HO) after statistical evaluation by NCSS (NCSS, Kaysville, Utah) with two-sample T-test range at the 5% level. The results of the current experiment suggested that humic acid had suppressed or counteracted the toxic effect of aluminum (Al3+) on both main and lateral root growth. Humic acid seems to block the effect of Al3+ on nutrient uptake, as tested by atomic absorption spectrophotometry (AAS) and flame photometery (FP). Al3+ content in the roots was significantly decreased by 219% in 50-μM HA and by 49% in 100-μM HA treatments respectively. Potassium (K+), sodium (Na+), and iron (Fe3+) were recorded as the other elements taken up in the greatest amounts among the tested nutrients, in addition to Al3+. Humic acid increased the contents of Na+, K+, manganese (Mn2+), and zinc (Zn2+) significantly in both concentrations of HA treatment compared to controls. The Fe3+ content in the roots decreased, in both treatments of HA, application by 252% and 32% respectively. The reduction in the former was significant.Article Citation - WoS: 259Citation - Scopus: 284Heavy Metal Removal From Waste Waters by Ion Flotation(Elsevier Ltd., 2007) Polat, Hürriyet; Erdoğan, D.Flotation studies were carried out to investigate the removal of heavy metals such as copper (II), zinc (II), chromium (III) and silver (I) from waste waters. Various parameters such as pH, collector and frother concentrations and airflow rate were tested to determine the optimum flotation conditions. Sodium dodecyl sulfate and hexadecyltrimethyl ammonium bromide were used as collectors. Ethanol and methyl isobutyl carbinol (MIBC) were used as frothers. Metal removal reached about 74% under optimum conditions at low pH. At basic pH it became as high as 90%, probably due to the contribution from the flotation of metal precipitates.