Browsing by Author "Şen, F."

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Carbon-Based Nanostructures and Nanomaterials
(Elsevier, 2020) Karaca, B.; Karataş, Y.; Cakar, A.B.; Gülcan, M.; Şen, F.
Carbon has been used in many different ways throughout history, including human life and technology. Since ancient times, coal, carbon black, and graphite have been used for writing and drawing. Recently, conjugated carbon nanomaterials especially carbon nanotubes and fullerenes have been used as a material to store energy due to its unique properties. In the last 10years, nanostructures and nanomaterials have taken attentions extensively due to having many advantages including excellent mechanical, thermal, chemical, and electrical. Therefore, carbon-based nanostructures and nanomaterials nowadays found the opportunity to be applied in numerous areas such as electronics, sensors, composite materials, drug delivery, energy conversion and storage, and field emission devices. In the 21st century, the capacity of these materials and the impressive aspects as environmentally safe and green fabrication processes and industrial production of carbon-based nanostructures and nanomaterials are extremely necessary, and therefore, it can be defined as the primary research field for technological and scientific applications. This section provides a broad overview of the fundamental properties of carbon-based nanostructures and nanomaterials, simple synthesis methods and a wide range of technological and industrial applications. © 2021 Elsevier Inc. All rights reserved.
Chemical and Microbiological Properties of Lake Aygır in Turkey and Usage of Drinking, Fisheries, and Irrigation
(Instituto Internacional de Ecologia, 2023) Çavuş, A.; Şen, F.
Since water is one of the essentials for life, the presence and quality of water in the habitat is extremely important. Therefore, water quality change and management of Lake Aygır was investigated in this study. For this, water samples collected from the lake and the irrigation pool between May 2015 and May 2016 were analyzed monthly. Spectrophotometric, titrimetric and microbiological methods were used to determine the water quality. According to some water quality regulations, HCO3, NH4, Cu, Mo, Br, fecal coliform and total suspended solid (TSS) values were found above the limit values. The other 29 parameters comply with Turkish national and international legislations. Lake Aygır was negatively affected by the surrounding settlements and agricultural activities. It is thought that the water resource should be monitored periodically and remedial studies should be done to prevent parameters exceeding the limits. However, Lake Aygır was generally suitable for drinking, use, fishing and irrigation. © 2023, Instituto Internacional de Ecologia. All rights reserved.
Different Sized Platinum Nanoparticles Supported on Carbon: an Xps Study on These Methanol Oxidation Catalysts
(American Chemical Society, 2007) Şen, F.; Gökaǧaç, G.
Different sized platinum nanoparticles on carbon supports have been prepared using PtCl4 (catalyst Ia) and H2PtCl6 (catalyst lia) as starting materials and 1-hexanethiol as a surfactant and then heated to 200°C (catalyst Ib and catalysts IIb), 300°C (catalyst Ic and catalysts IIc), and 400°C (catalyst Id and catalysts IId) for 4 h under argon gas. All the catalysts showed a face-centered cubic (fee) crystal structure as determined by X-ray diffraction. X-ray diffractograms and transmission electron microscopy results reveal that the platinum nanoparticles are homogeneously dispersed on the carbon support, exhibit narrow particle size distribution, and show no appreciable aggregation. The average platinum particle size as determined from XRD data was found to be ∼2.00, ∼2.56, ∼4.23, ∼4.52, ∼2.13, ∼2.77, ∼4.29, and ∼4.62 nm for catalysts Ia-d and IIa-d, respectively. X-ray photoelectron spectra of all the catalysts indicated that most (>70%) of the platinum nanoparticles have an oxidation state of zero and a small amount (<30%) have a +4 oxidation state with binding energies of 71.2-72.2 (Pt 4f7/2) and 74.3-75.5 eV (Pt4f7/2), respectively. Increasing the temperature during the heat treatment process results in an enlargement of platinum particle size, a positive shift in the binding energies of Pt(0) and Pt(IV), and a decrease in catalytic activity in the methanol oxidation reaction. © 2007 American Chemical Society.
Distribution of Fish Species in the Van Lake Basin
(Centenary University, 2016) Elp, M.; Atici, A.A.; Şen, F.; Duyar, H.A.
This study was carried out to determine the fish species of Van Lake Basin between in 2008-2012. Van Lake Basin is a closed basin that shaped approximately 2.3 % of Turkey. Because of closed basin character, the differences indicated in species diversity. Basin is rich in endemic species diversity with plant and animal species. This richness were reflected to fish species. All of the fish species naturally occurring in the lake basin are consist of endemic species. Alburnus tarichi, Alburnus timarensis, Barbus ercisianus, Capoeta cosswigi and Oxynoemacheilus ercisianus exhibited a natural distribution. Cyprinus carpio, Carassius gibelio, Gambusia holbrooki and Aphanius mento were constituted population from various water sources. In addition, escaped from fish farm sorvaccinated to water resources Oncorhynchus mykiss was unable to create the population. Barbus ercisianus and Capoeta cosswigi shown to create hybrid fish species in Zilan and Deliçay. Cyprinus carpio and Carassius carassius shown to create hybrid fish species in Nazik Lake. © 2016, Centenary University. All rights reserved.
Drinking Water Quality Properties of Ercis, Van-Turkey
(Centenary University, 2016) Atici, A.A.; Gültekin, A.; Şen, F.; Elp, M.
In this study, microbiological, physical, and chemical characters of drinking water supplied from city of Ercis were analyzed. Temperature, turbidity, conductivity, dissolved oxygen, biological oxygen demand, chemical oxygen demand, calcium, magnesium, total hardness, total alkalinity, free chloride, carbonate, bicarbonate, nitrite, nitrate, ammonia, phosphorus, zinc, copper, nickel, cobalt, cyanide, fluoride, aluminum, iron, potassium, manganese, molybdenum, silicon and microbiological parameters were analyzed in the laboratory. The results were evaluated according to “Turkish Regulation of Surface Water Quality Management, Turkish Water Pollution Control Regulations, TS 266, Turkish Regulation on Water Intended for Human Consumption”. © 2016, Centenary University. All rights reserved.
First Report of Ligula Intestinalis (Cestoda: Pseudophyllidea) in Barbus Ercisianus (Cypriniformes: Cyprinidae) From the Nemrut Crater Lake, Turkey
(Centenary University, 2022) Önalan, Ş.; Atici, A.A.; Sepil, A.; Şen, F.
Van Basin has a rich geographical structure in terms of water resources and endemic fish species. In this study, Ligula intestinalis parasite, which is the host of Barbus ercisianus living in Nemrut Crater Lake, was recorded for the first time. The parasite was described molecularly as well as morphologically. In this context, a primer set was designed for molecular identification for the 28S rRNA gene region of L. intestinalis. Real-Time PCR results with the designed primers gave positive results in all parasite samples. The results were confirmed by a single peak (87) in the HRM analysis. © 2022, Centenary University. All rights reserved.
Graphene Functionalizations on Copper by Spectroscopic Techniques
(Springer International Publishing, 2019) Gülcan, M.; Aygün, A.; Almousa, F.; Burhan, H.; Khan, A.; Şen, F.
Graphene is a two-dimensional allotrope of the carbon element, which is one of the most powerful materials of the 21st century. In order to facilitate the processing of the graphene, solvent-supported methods such as rotation coating, layer by layer assembly, and filtration are used. Single layer graphene prevents agglomeration of the material while reducing reactions occur. According to the studies in the literature, the chemical functionalization of graphene is performed by covalent and non-covalent modification techniques on substrate like copper. Besides, graphene can be used in many material production areas, such as polymer nanocomposites, drug delivery system, supercapacitor devices, solar cells, biosensors, and memory devices. © 2019, Springer Nature Singapore Pte Ltd.
Improving Catalytic Efficiency in the Methanol Oxidation Reaction by Inserting Ru in Face-Centered Cubic Pt Nanoparticles Prepared by a New Surfactant, Tert-Octanethiol
(2008) Şen, F.; Gökaǧaç, G.
PtRu/C catalysts, which have different atomic percent ratios of Pt and Ru (Pt/Ru = 0.8 (catalyst A), 2.1 (catalyst B), and 3.5 (catalyst C)), were prepared using PtCl4 and RuCl3 as starting materials and tert-octanethiol as a surfactant for the first time. Each was characterized by X-ray diffraction, transmission electron microscopy, energy dispersive analysis, X-ray photoelectron spectroscopy, cyclic voltammetry, and elemental analysis, and their activities were determined toward the methanol oxidation reaction. It has been found that catalyst A is 6 times more active toward the methanol oxidation reaction compared to the commercial catalyst. X-ray diffraction results indicated that more than 90% of the ruthenium in catalyst A inserts into the face-centered cubic (fcc) Pt crystalline structure, while more than 90% of Ru, present in catalyst B, remains as crystalline and/or amorphous Ru and/or RuO2. In catalyst C, approximately half of the Ru incorporates into the fcc platinum crystalline structure. © 2008 American Chemical Society.
Investigation of Water Quality Criteria of Drinking Waters in Center of Van, Turkey
(Centenary University, 2017) Çavuş, A.; Atici, A.A.; Şen, F.
In this study, it has been investigated whether different water resources, distributed to networks as drinking water in the center of Van, are appropriate to consumption according to physical, chemical and microbiological analyzes. Turbidity, electrical conductivity, temperature, dissolved oxygen, pH was measured in the water received from the network water. Biological oxygen demand, chemical oxygen demand, calcium, magnesium, total hardness, total alkalinity, chloride, carbonate, bicarbonate, nitrite, nitrate, ammonia, phosphorus, zinc, copper, nickel, cobalt, cyanide, fluoride, aluminum, iron, potassium, manganese, molybdenum and microbiological analyzes were analyzed at a laboratuary. The results were generally found to be appropriate for the values given in our country’s regulations on drinking water. © 2017, Centenary University. All rights reserved.
Magnetic Nanoparticles
(Elsevier, 2020) Acidereli, H.; Karataş, Y.; Burhan, H.; Gülcan, M.; Şen, F.
Magnetic nanoparticles (MNPs) have widespread attention because of their unique features. For a few decades, growing development in chemical synthesis of nanomaterials and material surface modification have been seen and performed in numerous applications including biomedicine, biotechnology, catalysis, magnetic chemistry thermoelectric materials, etc. Various methods for fabrication of MNPs which have a controllable size, distribution, and surface modification have been reported. In these methods, several techniques containing irradiation, microwave, ultrasonication, vapor deposition, electrochemical, and microwave are applied to produce MNPs either in bottom-up or top-down processes. Generally, magnetic synthesis of nanoparticles is carried out by using these two processes. Nanomaterials with magnetic properties have wide applications in many fields such as biology, medicine, and engineering. In this section, the recent developments in the structures, occurrences, most commonly used samples, and common areas of use of the MNPs are given. © 2021 Elsevier Inc. All rights reserved.
Pt-Based Catalysts for Alcohol Oxidation
(Elsevier, 2021) Burhan, H.; Arikan, K.; Bekmezci, M.; Gurc, T.; Şen, F.
The development of fuel cell technologies and the use of clean energy sources have recently accelerated considerably. Fuel cells are electrochemical devices that convert chemical energy into electrical energy with an efficiency of 40%-80%. Fuel cells have many advantages, such as high efficiency, environmental friendliness, silent operation, and light weight, and it can be applied in vehicles and power plants. A fuel cell consists of an anode, the electrolyte medium that transmits the hydrogen ion and the cathode. As the fuel feeds from the anode alcohol, the cathode meets the oxygen source for the air itself. As a result of reactions in the electrodes, electrical energy is produced and water vapor from cathode, waste fuel, and CO2 is given off from the anode as by-products. In this chapter, detailed information about the types and properties of platinum-based catalysts for the alcohol oxidation of fuel cells and their applications are provided by compiling information from the research literature. In addition, economic evaluations were made by specifying the positive and negative aspects of these materials. © 2021 Elsevier Inc. All rights reserved.
A Study of the Some Growth Parameters of Barbel (Barbus Plebejus Ercisianus, Karaman, 1971) Living in the Koçköprü Dam Lake Basin-Turkey
(2006) Elp, M.; Çetinkaya, O.; Kankaya, E.; Şen, F.; Ünal, G.
This study was carried out to determine some growth parameters of barbel populations living in the Koçköprü Dam Lake and its inlets between April 2000 and October 2001. The barbel species are shown a widespread distribution in Turkey. The species is native in study area, has economic value and is fished local fishermen. A total of 324 individuals were sampled. The maximum age of individuals was determined as VII, fork length was 33.8 cm and weight was 428.0 g. Females were found larger than males in size. Condition factor values were determined as 1.210±0.009 for males, 1.266±0.017 for females and 1.293±0.030 for juveniles. In overall, condition factor of females was higher than males. Length-weight relationship was determined for whole samples as logW = -1.841+2.934 logL. © 2006 Asian Network for Scientific Information.
Ternary/Quaternary Nanomaterials for Direct Alcohol Fuel Cells
(Elsevier, 2021) Altuner, E.E.; Gur, T.; Şen, F.
In this chapter, ternary and quaternary nanomaterials that increase electrocatalytic activity in direct alcohol fuel cells (DAFCs) are mentioned. Because nanosized materials achieve their target quickly due to the desired nanostructure, they give quite good results. These types of materials also increase activation and efficiency of the alcohol oxidation reaction in DAFCs. Undesired reactions occurring at the anode and cathode in DAFCs, the instability of platinum, and its corrosion have led to the need for multiple nanoelectrocatalysts such as ternary and quaternary supporting platinum. For this reason, binary, ternary, and quaternary systems were created to be able to increase the efficiency of the DAFCs. © 2021 Elsevier Inc. All rights reserved.