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Article Citation - WoS: 21Citation - Scopus: 21Synthesis and Properties of a Novel Redox Driven Chemiluminescent Material Built on a Terthienyl System(Pergamon-elsevier Science Ltd, 2009) Atilgan, Nurdan; Algi, Fatih; Onal, Ahmet M.; Cihaner, AtillaA novel redox driven chemiluminescent material built on a terthienyl system, namely 5,7-di-ethylenedioxythiophen-2-yl-2,3-dihydro-thieno[3,4-d]pyridazine-1,4-dione (ETE-Lum), which is soluble in both organic media and basic aqueous solution was synthesized and characterized. Furthermore, its polymer, PETE-Lum, which is one of the most rare examples of chemiluminescent polymeric materials bearing a pyridazine unit, was obtained successfully by electrochemical means. Both of the materials give chemiluminescence either by treatment with oxidants (H2O2 and/or KMnO4) or by the application of a potential pulse. (C) 2009 Elsevier Ltd. All rights reserved.Article Citation - WoS: 45Citation - Scopus: 46Carbon Nanotube-Graphene Supported Bimetallic Electrocatalyst for Direct Borohydride Hydrogen Peroxide Fuel Cells(Pergamon-elsevier Science Ltd, 2021) Uzundurukan, Arife; Akca, Elif Seda; Budak, Yagmur; Devrim, YilserAt present study, carbon nanotube-graphene (CNT-G) supported PtAu, Au and Pt catalysts were prepared by microwave-assisted synthesis method to investigate the direct liquid-fed sodium borohydride/hydrogen peroxide (NaBH4/H2O2) fuel cell performance. Prepared catalysts were characterized by TGA, XRD, TEM, ICP-OES, cyclic voltammetry and rotating disc electrode (RDE) voltammetry. The catalysts were tested in a single NaBH4/H2O2 fuel cell with 25 cm(2) active area to evaluate fuel cell performance. The effects of temperature and fuel concentration on fuel cell performance were examined to observed best operating conditions. As a result of direct NaBH4/H2O2 fuel cell experiments, maximum power densities of 139 mW/cm(2), 125 mW/cm(2) and 113 mW/cm(2) were obtained for PtAu/CNT-G, Au/CNT-G and Pt/CNT-G catalysts, respectively. PtAu/CNT-G catalyst showed the enhanced NaBH4/H2O2 fuel cell performance, which was higher than the Pt/CNT-G catalyst and Au/CNT-G catalyst at 50 degrees C. The enhanced NaBH4/H2O2 performance can be attributed to synergistic effects between Pt and Au particles on CNT-G support providing a better catalyst utilization and interaction. These results suggest that the prepared PtAu/CNT-G catalyst is a promising anode catalyst for NaBH4/H2O2 fuel cell application. (c) 2020 Elsevier Ltd. All rights reserved.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.Letter Amendments on "application of Mises Yield Criterion To Rotating Solid Disk Problem" by N. Aleksandrova [int. J. Eng. Sci. 51 (2012) 333-337](Pergamon-elsevier Science Ltd, 2012) Eraslan, Ahmet N.; Akis, Tolga[No Abstract Available]Article Citation - WoS: 36Citation - Scopus: 43Development of a Personalized Thermal Comfort Driven Controller for Hvac Systems(Pergamon-elsevier Science Ltd, 2021) Turhan, Cihan; Simani, Silvio; Akkurt, Gulden Gokcen; Gokcen Akkurt, GuldenIncreasing thermal comfort and reducing energy consumption are two main objectives of advanced HVAC control systems. In this study, a thermal comfort driven control (PTC-DC) algorithm was developed to improve HVAC control systems with no need of retrofitting HVAC system components. A case building located in Izmir Institute of Technology Campus-Izmir-Turkey was selected to test the developed system. First, wireless sensors were installed to the building and a mobile application was developed to monitor/ collect temperature, relative humidity and thermal comfort data of an occupant. Then, the PTC-DC algorithm was developed to meet the highest occupant thermal comfort as well as saving energy. The prototypes of the controller were tested on the case building from July 3rd, 2017 to November 1st, 2018 and compared with a conventional PID controller. The results showed that the developed control algorithm and conventional controller satisfy neutral thermal comfort for 92 % and 6 % of total measurement days, respectively. From energy consumption point of view, the PTC-DC decreased energy consumption by 13.2 % compared to the conventional controller. Consequently, the PTC-DC differs from other works in the literature that the prototype of PTC-DC can be easily deployed in real environments. Moreover, the PTC-DC is low-cost and user-friendly. (c) 2021 Elsevier Ltd. All rights reserved.Review Citation - WoS: 39Citation - Scopus: 43Hydropower in Turkey: Analysis in the View of Vision 2023(Pergamon-elsevier Science Ltd, 2013) Melikoglu, MehmetTurkey is a recently developed country, a regional power in the Middle East and an economic powerhouse of the region. Turkey's electricity demand is continuously increasing due to fast economic growth coupled with the country's vibrant young population. It is envisaged that this demand would keep on increasing almost exponentially in the next decade according to the recently avowed Vision 2023 agenda. According to which, the Turkish government ambitiously wants to provide 30.0% of the country's electricity demand from renewable energy sources by 2023. Turkey has vast renewable energy potential including hydro, geothermal, solar and wind. However, historically there is only one playmaker that is hydropower. Thus a detailed review of the current status and future prospects of Turkish hydropower market is urgently needed to generate a roadmap for the Vision 2023 agenda. This paper was intended to provide that vital information. Currently, more than 25.0% or 57.5 TWh of the country's electricity demand is supplied from hydropower. According to official projections this would increase to approximately 116.0 TWh in 2023. In this study, hydropower's supply rate of Turkey's annual electricity demand was assessed based on the official projections and a forecast was generated. Results showed that between 22.0% and 27.0% of Turkey's annual electricity demand should be supplied from hydropower in 2023. Therefore, between 22.5 TWh and 45.0 TWh of electricity should be generated from renewable energy sources other than hydropower to provide a total of 30.0% renewable energy based electricity generation in 2023. (C) 2013 Elsevier Ltd. All rights reserved.Article Citation - WoS: 14Citation - Scopus: 15Lmi Approach To the Global Robust Stability of a Larger Class of Neural Networks With Delay(Pergamon-elsevier Science Ltd, 2007) Singh, VimalSufficient conditions in the form of linear matrix inequality for the uniqueness and global asymptotic stability of the equilibrium point of a large class of uncertain neural networks with delay are presented. The conditions are based on norm-bounded uncertainties. An example is given to show the effectiveness of the obtained results. A comparison is made between the present approach and an earlier approach due to Lu, Rong and Chen. An error is corrected in an earlier publication. (c) 2006 Elsevier Ltd. All rights reserved.Article Citation - WoS: 59Citation - Scopus: 68Generalized (c)-conditions and Related Fixed Point Theorems(Pergamon-elsevier Science Ltd, 2011) Karapinar, Erdal; Tas, Kenan; Karapnar, ErdalIn this manuscript, the notion of C-condition [K. Suzuki, Fixed point theorems and convergence theorems for some generalized nonexpansive mappings, J. Math. Anal. Appl. 340 (2008) 1088-1095] is generalized. Some new fixed point theorems are obtained. (C) 2011 Elsevier Ltd. All rights reserved.Article Citation - WoS: 84Citation - Scopus: 94Investigation of Micro-Combined Heat and Power Application of Pem Fuel Cell Systems(Pergamon-elsevier Science Ltd, 2018) Budak, Yagmur; Devrim, YilserThis study focuses on the investigating different working temperature effect on Proton Exchange Membrane Fuel Cell (PEMFC) stack performance, micro-combined heat and power (mu CHP) application and their simple payback time. LT-PEMFC and HT-PEMFC short stacks were designed and analyzed for 480 W net power output. Liquid cooling method was choosing for the cooling the PEMFC stacks due for efficient mu CHP applications. The experimental studies were carried out by using 13 cells HT-PEMFC and 6 cells LT-PEMFC short stacks and design parameters were determined. 1.2 kW PEMFCs with mu CHP systems with different working temperature were designed based on electrochemical data obtained from short stack testing. The proposed PEMFC systems can supply electric and hot water. The highest mu CHP system efficiency was calculated with a value of 92% for HT-PEMFC based system. The corresponding electrical and thermal efficiencies are 48% and 44%, respectively. In this study, two important parameters have been analyzing: efficiency and simple payback time. By using mu CHP application, both natural gas and H-2 based PEMFC systems SPT values are reduced.Article Citation - WoS: 2Citation - Scopus: 2Structural, Electrical and Anisotropic Properties of Tl4se3< Chain Crystals(Pergamon-elsevier Science Ltd, 2009) Qasrawi, A. F.; Gasanly, N. M.The structure, the anisotropy effect on the current transport mechanism and the space charge limited current in Tl4Se3S chain crystals have been studied by means of X-ray diffraction, electrical conductivity measurements along and perpendicular to the crystal's c-axis and the current voltage characteristics. The temperature-dependent electrical conductivity analysis in the region of 150-400 K, revealed the domination of the thermionic emission of charge carriers over the chain boundaries above 210 and 270 K along and perpendicular to the c-axis, respectively. Below these temperatures, the variable range hopping is dominant. At a consistent temperature range, the thermionic emission analysis results in conductivity activation energies of 280 and 182 meV, along and perpendicular to the c-axis, respectively. Likewise, the hopping parameters are altered significantly by the conductivity anisotropy. The current-voltage characteristics revealed the existence of hole trapping state being located at 350 meV above the valence band of the crystal. (C) 2009 Elsevier Ltd. All rights reserved.
