Karamzadeh S.,Istanbul Aydin University
Applied Computational Electromagnetics Society Journal | Year: 2017
A very compact modified simple structure Ultra-Wideband (UWB) antenna with a size of 18 mm by 30 mm is presented for polarization diversity applications. The antenna employs two orthogonal monopole antenna to achieve polarization diversity over the UWB. The antenna was fabricated to study the performance such as S-parameters, radiation pattern, radiation efficiency, peak gain, envelope correlation coefficient and group delay. The measured results demonstrated that the proposed antenna has not only UWB (147.96% impedance bandwidth) but also good isolation less than about -25 dB. Moreover, the system fidelity factor is sufficient for pulse transmission with average 89.6% and 85.3% for ports 1 and 2, respectively. Furthermore, a low envelope correlation coefficient of less than 0.001 occurred, too. All these features show that the proposed UWB MIMO antenna can meet the requirement of MIMO/diversity of communication applications well. © ACES.
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: SEC-2011.7.6-1 | Award Amount: 4.40M | Year: 2012
The EU aims to consolidate and enhance its disaster response capacity by creating a European Emergency Response Center. This institution should be complimented by a standardised European training curriculum for professional crisis response. A European multi-disciplinary team of experts is collaborating to develop a standardised curriculum for international crises management hereby referred to as DITAC. The DITAC project aims to develop a holistic and highly structured curriculum for first responders and strategic crisis managers that are tasked in dealing with disasters on a national and international scale. The curriculum will tackle dynamic challenges facing disaster incident managers in order to enhance the efficiency, efficacy, coordination, coherence and appropriateness of their response efforts. These skills are crucial because of an alarming increase in the frequency, intensity and complexity of disasters while governments are simultaneously facing budgetary constraints on humanitarian aid due to overwhelming sovereign debt. This curriculum aims to establish a standard practice among European disaster and crisis managers in order to pool resources and expertise by cultivating a network of dedicated professionals that think alike and can communicate beyond obscure bureaucratic structures. Educational integration of crisis managers from national, regional and international authorities, NGOs and existing training institutions from around the world leads to a more concerted effort in disaster response. The curriculum will fulfill EU criteria on crisis management but will also have a global outreach since the EU is the largest donor of humanitarian aid to developing countries. This satisfies the moral obligations the EU feels toward less fortunate nations and gives European crises managers an unbridled opportunity to gain hands-on experience in disaster stricken zones around the world. This will increase EU resilience when facing disasters closer to home.
Subasi M.G.,Istanbul Aydin University |
Inan O.,Selcuk University
Lasers in Medical Science | Year: 2014
This study aimed to evaluate the surface changes caused in zirconia by different surface treatments and the influence of the surface treatment and cement selection on bonding to zirconia under aging. Sintered zirconia specimens were divided into five groups (n = 31) based on the surface treatment, namely, control, air abrasion, silica coating, laser and air abrasion + laser. After surface treatment, surface roughness and microscope analyses were performed on one specimen of each group. Composite cylinders were then bonded to conditioned ceramics using RelyX U100 (RXU), Clearfil Esthetic Cement (CEC) and Panavia F (PF) (n = 10). After 24 h, the bonded specimens were subjected to thermal cycling (6,000 times), and then, a shear bond strength test was conducted. The roughness values were analysed using Kruskal-Wallis and Mann-Whitney U tests, and the bond strengths were analysed by two-way analysis of variance and Duncan's test. The relationship between the roughness and the bond strength was determined by Spearman's correlation analysis. Specimens subjected to surface treatments were rougher than the control specimen (p < 0.000). However, there were no significant differences between the air abrasion and air abrasion + laser groups and the silica coating and laser groups. Specimens treated with laser showed lower bond strengths irrespective of the resin cement used. CEC and/or PF showed higher bond strengths than RXU for each surface treatment group. No significant relationship was observed between the roughness and the bond strength. The results of this study showed that all the surface treatments, except for laser irradiation, were suitable for treating zirconia ceramics. Cement selection was found to be more important than surface treatment, and phosphate monomer-containing cements were suitable for cementing zirconia. © 2012 Springer-Verlag London.
Simsek M.,Yildiz Technical University |
Cansiz S.,Istanbul Aydin University
Composite Structures | Year: 2012
This paper studies the dynamic responses of an elastically connected double-functionally graded beam system (DFGBS) carrying a moving harmonic load at a constant speed by using Euler-Bernoulli beam theory. The two functionally graded (FG) beams are parallel and connected with each other continuously by elastic springs. Six elastically connected double-functionally graded beam systems (DFGBSs) having different boundary conditions are considered. The point constraints in the form of supports are assumed to be linear springs of large stiffness. It is assumed that the material properties follow a power-law variation through the thickness direction of the beams. The equations of motion are derived with the aid of Lagrange's equations. The unknown functions denoting the transverse deflections of DFGBS are expressed in polynomial form. Newmark method is employed to find the dynamic responses of DFGBS subjected to a concentrated moving harmonic load. The influences of the different material distribution, velocity of the moving harmonic load, forcing frequency, the rigidity of the elastic layer between the FG beams and the boundary conditions on the dynamic responses are discussed. © 2012 Elsevier Ltd.
Utlu Z.,Istanbul Aydin University |
Parali U.,Istanbul Aydin University
Energy Conversion and Management | Year: 2013
Thermophotovoltaics (TPV) are the use of the photovoltaic effect to generate electricity from a high-temperature thermal (infrared) source. This study deals with to provide an overview of heat recovery by TPV from industrial high-temperature processes in Turkish industrial sector. The paper reviews the relevant facts about TPV technology and the high-temperature industry and identifies three principle locations for TPV heat recovery. For each location, one example process is assessed in terms of applicability of TPV impact on the existing process and power scale. Knowledge of these factors should contribute to the design of an optimum TPV system. In the TIS, the total technical-potential energy recovery in the high-temperature industry using deployed and demonstrated heat recovery devices for product, flue gas, and wall heat recovery was estimated as 447.8 PJ/year. However, an estimation from 22.40 PJ/year to 67.45 PJ/year can be achieved according to the TPV efficiencies. Also, the paper estimates the range of possible energy savings and the reduction in CO emission using TPV in the high-temperature industry. It is expected that this study will be very beneficial in developing energy policies of countries in terms of the usage of waste energy efficiency. © 2013 Published by Elsevier Ltd. All rights reserved.
Utlu Z.,Istanbul Aydin University |
Kincay O.,Yildiz Technical University
Energy | Year: 2013
In this study, a pulp and paper mill (PPM) in the SEKA Papermaking Plant in İzmit, Turkey, is analysed through energy and exergy balances. The plant utilises recycled waste paper for papermaking. This type of raw material input makes the process highly sophisticated. The pulping uses strictly mechanical processes, such as digestion, separation by screening and hydrocyclone, and refining. The milling, as an integrated process, provides the final operations necessary to prepare the conditions required for the end-product by stock-preparation, wiring, rolling, and drying by dewatering, pressing, and evaporation. The possibility of making the entire process more thermodynamically efficient is discussed by calculating the energy and exergy losses for all the mechanical and physical sub-processes. The study shows that the energy efficiencies for each of the mechanical and physical steps in the PPM vary between 34% and 97.4%, whereas the exergy efficiencies vary between 30.2% and 94.2%. In conclusion, based on the results from the energy and exergy flow analyses, the exergy output can be improved through more efforts directed primarily to further measurements toward more efficient energy utilisation in the PPM. © 2013 .
Kasapbasi E.E.,Istanbul Aydin University |
Whangbo M.-H.,North Carolina State University
Inorganic Chemistry | Year: 2012
Recently it was discovered that the iron coordination complex L N4Fe(II)(OTf)2 (1) (LN4 = neutral tetraazadendate ligand and OTf = OSO2CF3) and its analogues are efficient water oxidizing catalysts (WOCs) in aqueous acidic solution with excess amount of ceric(IV) ammonium nitrate (CAN), [Ce(IV)(NO 3)6](NH4)2, as sacrificial oxidants. The probable mechanism of water oxidation by these catalysts was explored on the basis of density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations for 1 as a representative WOC. We examined the conversion of 1 to the resting intermediate [LN4Fe(IV)(O)(OH2)]2+ [2(IV)] as well as two catalytic cycles involving 2(IV): one proposed by Fillol et al. [Nat. Chem. 2011, 3, 1] in which the Fe oxidation states of the intermediate species vary from +2 to +5, and the alternative cycle in which they remain constant at +4. In addition, we investigated the role of the sacrificial oxidant CAN in driving the catalytic cycle. Our DFT and TD-DFT calculations confirm the experimental observation that 2(IV) is the resting species, and indicate that the catalytic cycle in which the Fe oxidation states of the intermediate species remain at +4 is energetically more favorable. © 2012 American Chemical Society.
Utlu Z.,Istanbul Aydin University
Energy | Year: 2015
In this study, the potential for waste heat recovery is examined based on real data from 1990 to 2011 (a 21-year period) for processes at low-, medium- and high-temperature levels. The first part of this study included a theoretical analysis for determining the potential for heat recovery at these temperature stages. Second part stated an application in the industrial sector. This study is conducted using actual data for this sector from 1990 to 2011. The total available energy recovery from waste heat recovery appliances for products, flue gas and wall heat recovery was calculated to be 224-503PJ over the years studied. The available waste heat potential from the total energy in this sector is determined to be 36 to 40% for these years. The technical potential is estimated to be 55 to 65% of these values. The total technical-potential waste energy recovery in the low, medium, and high temperature stages using waste heat recovery appliances for products, flue gas and wall heat recovery was estimated to be from 224PJ to 503PJ over the years studied. Usage of technology device according to efficiencies for the sector was estimated to be 22.40PJ/year to 67.45PJ/year. © 2014 Elsevier Ltd.
Ozkan H.,Istanbul Aydin University
Philosophical Magazine | Year: 2014
The temperature dependence of the bulk modulus of ZrB2 above room temperature was calculated by using the equations by Garai and Laugier (J. Appl. Phys. 101 (2007) p.023514) and Lawson and Ledbetter (Philos Mag. 91 (2011) p.1425). The present calculations involve the accurate data for pressure derivative of the bulk modulus for the Anderson-Grüneisen parameter in addition to the other experimental parameters involved. It is interesting to note that the cited equations derived by different thermodynamic approaches give almost equivalent values for the temperature dependencies of the bulk modulus of ZrB2. The present results for the temperature derivatives of the bulk modulus of ZrB2 vary from -0.016 GPa/K at 300-400 K to -0.022 GPa/K at 1500-1600 K, being in good agreements with the corresponding experimental values. © 2013 Taylor & Francis.
Agency: European Commission | Branch: H2020 | Program: CSA | Phase: MSCA-NIGHT-2014 | Award Amount: 105.67K | Year: 2014
The overall concept of our proposal is Art of science for both years respectively taking place on Friday 26 Septemper 2014 and Friday 25 September 2015 where we intend to generate an awareness and interest towards science by bringing scientists and all sections of the public close to each together in Istanbul, Turkey. Here, with this concept, we would like to enhance public recognition of researchers and their work, encourage active participation into scientific planning, experimentation and outcomes in one approache. Our approach is to assist the participants to be acquainted with how they live, love, fun and learn science in their daily life. For example, we will present them opportunities to the see how science affects our life, to experience the science in daily life by hands-on and minds-on activities, and to shape their view of science as a way of knowing. The participants will also have the opportunity to be introduced to the latest scientific developments in various fields by meeting and discussing with scientists. Vice versa, the researchers will find chance to make their work publically known. Furthermore, students at all levels will make meaning of their science courses, feel themselves closer to science and scientists, and eventually become more confident about science. Additional idea of the researchers night is to recognize the participants to be aware of the role of European Union framework programmes, the impact and effect they have had on the well-being of the public. This idea will be introduced by several activities involving participants and facilities demonstrated to the participants in EU corner.