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Mula, Turkey

Kone A.I.,Mula University | Buke T.,University of Science and Arts of Iran
Renewable and Sustainable Energy Reviews | Year: 2010

The accelerating use of fossil fuels since the Industrial Revolution and the rapid destruction of forests causes a significant increase in greenhouse gases. The increasing threat of global warming and climate change has been the major, worldwide, ongoing concern especially in the last two decades. The impacts of global warming on the world economy have been assessed intensively by researchers since the 1990s. Worldwide organizations have been attempting to reduce the adverse impacts of global warming through intergovernmental and binding agreements. Carbon dioxide (CO2) is one of the most foremost greenhouse gases in the atmosphere. The energy sector is dominated by the direct combustion of fuels, a process leading to large emissions of CO2. CO2 from energy represents about 60% of the anthropogenic greenhouse gas emissions of global emissions. This percentage varies greatly by country, due to diverse national energy structures. The top-25 emitting countries accounted 82.27% of the world CO2 emissions in 2007. In the same year China was the largest emitter and generated 20.96% of the world total. Trend analysis is based on the idea that what has happened in the past gives traders an idea of what will happen in the future. In this study, trend analysis approach has been employed for modelling to forecast of energy-related CO 2 emissions. To this aim first, trends in CO2 emissions for the top-25 countries and the world total CO2 emissions during 1971-2007 are identified. On developing the regression analyses, the regression analyses with R2 values less than 0.94 showing insignificant influence in statistical tests have been discarded. Statistically significant trends are indicated in eleven countries namely, India, South Korea, Islamic Republic of Iran, Mexico, Australia, Indonesia, Saudi Arabia, Brazil, South Africa, Taiwan, Turkey and the world total. The results obtained from the analyses showed that the models for those countries can be used for CO 2 emission projections into the future planning. The calculated results for CO2 emissions from fitted curves have been compared with the projected CO2 emissions given in International Energy Outlook 2009 of U.S. Department of Energy calculated from "high economic growth case scenario", "reference case scenario" and "low economic growth case scenario" respectively. Agreements between calculated results and the projected CO2 emissions from different scenarios are in the acceptable range. © 2010 Elsevier Ltd. All rights reserved.

Yuzbas S.,Mula University
Computers and Mathematics with Applications | Year: 2012

In this paper, we present a numerical approach for solving the system of multi-pantograph equations with mixed conditions. This system is usually difficult to solve analytically. By expanding the approximate solutions by means of the Bessel functions of first kind with unknown coefficients, the proposed approach consists of reducing the problem to a linear algebraic equation system. The unknown coefficients of the Bessel functions of first kind are computed using the matrix operations of derivatives together with the collocation method. An error estimation is given. The reliability and efficiency of the proposed scheme are demonstrated by some numerical examples. All of the numerical computations have been performed on a computer with the aid of a program written in Matlab. © 2011 Elsevier Ltd. All rights reserved.

In this work the phase equilibriums, the mesomorphic and morphologic properties of the binary hexadecyltrimethyl ammonium bromide/water and ternary hexadecyltrimethyl ammonium bromide/water/1-decanol lyotropic systems have been studied. The shape of micelles in the lyotropic phase has been estimated. Typical textures of the nematic-calamitic, nematic-discotic, hexagonal and lamellar mesophases and the phase diagrams of these lyotropic systems are presented. ©2014 Elsevier B.V. All rights reserved.

Caklr A.,Mula University | Caklr A.,University of Duisburg - Essen | Acet M.,University of Duisburg - Essen | Farle M.,University of Duisburg - Essen
Physical Review B - Condensed Matter and Materials Physics | Year: 2016

Exchange bias is observed in ferromagnetic/antiferromagnetic (FM/AF) layered stacks and in materials with neighboring ferromagnetic and antiferromagnetic granules. The latter is commonly observed in Ni-Mn-based martensitic Heusler alloys. In general, the exchange-bias effect is identified as horizontally shifted hysteresis loop when the system is field cooled from high temperatures. We report here loop shifts not only under field-cooled but also under zero-field-cooled conditions in magnetically granular martensitic Ni50Mn50-xSnx Heusler alloys in the compositional range 13.0≥x≥8.9. Under zero-field-cooled conditions, the initially applied field can carry the system over energy barriers and stabilize a spin-reconfigured state so that a negatively shifted hysteresis loop can also occur here as in the field-cooled state. Spin reconfiguration occurs when the relative size of the AF and FM regions as well as the relative strength of the of AF and FM interactions are in balance. © 2016 American Physical Society.

Yalcinbac S.,Celal Bayar University | Aynigul M.,Celal Bayar University | Sezer M.,Mula University
Journal of the Franklin Institute | Year: 2011

In this paper, a numerical method based on polynomial approximation, using Hermite polynomial basis, to obtain the approximate solution of generalized pantograph equations with variable coefficients is presented. The technique we have used is an improved collocation method. Some numerical examples, which consist of initial conditions, are given to illustrate the reality and efficiency of the method. In addition, some numerical examples are presented to show the properties of the given method; the present method has been compared with other methods and the results are discussed. © 2011 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.

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