Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
Browse
56 results
Search Results
Article Citation - WoS: 361Citation - Scopus: 396The Use of Ecological Footprint in Estimating the Environmental Kuznets Curve Hypothesis for BRICST by Considering Cross-Section Dependence and Heterogeneity(Elsevier, 2020-06) Dogan, Eyup; Ulucak, Recep; Kocak, Emrah; Isik, CemA vast body of literature estimates the impact of economic growth on environmental degradation in the framework of EKC model. Typical empirical studies proxy environmental degradation with CO2 emissions; however, this indicator does not consider the complex nature of environmental degradation. To fulfill this omission, ecological footprint that tracks the use of multiple categories of productive surface areas is used as proxy for the environment. Moreover, studies that do not consider issues of heterogeneity and cross-sectional dependence may not produce reliable outcomes. Hence, the present study re-investigates the validity of the EKC hypothesis for BRICST (Brazil, Russia, India, China, South Africa, Turkey) by using ecological footprint and considering the mentioned issues in the estimation process. Based on the annual data covering the period of 1980-2014, excluding Russia due to data unavailability, empirical results show that the EKC hypothesis is not valid, and energy intensity and energy structure are important determinants of environmental degradation. In line with the empirical outputs, possible policy suggestions are discussed in the present study. (C) 2020 Elsevier B.V. All rights reserved.Article Citation - WoS: 143Citation - Scopus: 146The Impacts of Different Proxies for Financialization on Carbon Emissions in Top-Ten Emitter Countries(Elsevier, 2020-10) Amin, Azka; Dogan, Eyup; Khan, ZeeshanThe nexus of financialization and carbon emissions has been widely discussed in the literature. A vast body of literature that estimates the impact of financialization on carbon emissions proxies financialization with either domestic credit or market capitalization. However, these representatives do not fully respond to the complicated nature of financial development. To till the gaps in the existing literature, nine different proxies for financial development are used in the links with carbon emissions in the framework of EKC theory for the years 1980-2014. This study exposes reliable and robust empirical results due to the use of a number of proxies for financialization and second-generation econometric approaches in the empirical analysis. The quantile regression approach deals with unobserved heterogeneity for each cross-section and estimates different slope parameters at varying quantiles. Because non-normality and heterogeneity are detected in datasek quantile regression provides more robust and reliable estimates than conventional econometric techniques. Results from quantile regression estimator support mixed effects of financial development on carbon emissions over quantiles: in addition, the impact of financial development on carbon emissions is varying not only for each quantile but also for different proxies of financial development. The EKC hypothesis is validated for the top-ten emitter economies. Interpretations and policy suggestions are further discussed in the present study. (C) 2020 Elsevier B.V. All rights reserved.Article Citation - WoS: 359Citation - Scopus: 412The Impact of Trade Openness on Global Carbon Dioxide Emissions: Evidence From the Top Ten Emitters Among Developing Countries(Elsevier, 2016-08) Ertugrul, Hasan Murat; Cetin, Murat; Seker, Fahri; Dogan, EyupThis study aims to analyze the relationship between carbon dioxide (CO2) emissions, trade openness, real income and energy consumption in the top ten CO2 emitters among the developing countries; namely China, India, South Korea, Brazil, Mexico, Indonesia, South Africa, Turkey, Thailand and Malaysia over the period of 1971-2011. In addition, the possible presence of the EKC hypothesis is investigated for the analyzed countries. The Zivot-Andrews unit root test with structural break, the bounds testing for cointegration in the presence of structural break and the VECM Granger causality method are employed. The empirical results indicate that (i) the analyzed variables are co-integrated for Thailand, Turkey, India, Brazil, China, Indonesia and Korea, (ii) real income, energy consumption and trade openness are the main determinants of carbon emissions in the long run, (iii) there exists a number of causal relations between the analyzed variables, (iv) the EKC hypothesis is validated for Turkey, India, China and Korea. Robust policy implications can be derived from this study since the estimated models pass several diagnostic and stability tests. (C) 2016 Elsevier Ltd. All rights reserved.Article Citation - WoS: 196Citation - Scopus: 225The Impact of Renewable Energy Consumption to Economic Growth: A Replication and Extension of Inglesi-Lotz (2016)(Elsevier, 2020-08) Dogan, Eyup; Altinoz, Buket; Madaleno, Mara; Taskin, DilvinThis study replicates and extends the results presented in a top-cited article in this journal, Inglesi-Lotz (2016), which analyzes the impact of renewable energy consumption to economic growth for the OECD countries by applying the ordinary least squares with fixed effect estimator on the data from 1990 to 2010. By using the same data and methods, this study first produces and compare empirical results with those reported in the original article. Then, it applies a set of new econometric methods on the same data to address heterogeneity in renewable energy and economic growth across the analyzed group of countries. The panel quantile regression estimation shows that the effect of renewable energy consumption on economic growth is positive for lower and lowmiddle quantiles; however, its effect becomes negative for middle, high-middle, and higher quantiles when renewable energy consumption is proxied by the absolute value. Furthermore, a negative impact of renewable energy on economic growth is observed in almost all quantiles when it is proxied by the share of renewable energy consumption to total energy consumption. These results greatly differ from those of the original study (C) 2020 Elsevier B.V. All rights reserved.Article Citation - WoS: 12Citation - Scopus: 18The Impact of Error Control Schemes on Lifetime of Energy Harvesting Wireless Sensor Networks in Industrial Environments(Elsevier, 2020-06) Tekin, Nazli; Gungor, Vehbi CagriDue to the harsh channel conditions of the industrial environments, the data transmission over the wireless channel suffers from erroneous packets. The energy consumption of error control schemes is of great importance for battery-limited Wireless Sensor Networks (WSNs) in industrial environments. In this paper, the lifetime analysis of error control schemes, i.e., Automatic Repeat Request (ARQ), Forward Error Correction (FEC) and Hybrid ARQ (HARQ), is presented under different industrial environment channel conditions. Furthermore, the impact of energy harvesting methods on the network lifetime is investigated. A novel Mixed Integer Programming (MIP) framework is developed to maximize the network lifetime while meeting application reliability. Performance results show that utilizing HARQ-II error control scheme for Mica2 and BCH(31,21,5) for Telos improves the network lifetime while meeting the desired application reliability rate.Article The Ground State Properties of Two Dimensional Fermi Gas System Confined in a Potential Composed of Harmonic and a Gaussian Terms(Elsevier, 2019-01) Gulveren, Berna; Sahin, Mehmet; Atav, UlfetIn this work, the ground state properties of two dimensional Fermi gas system interacting in a potential con- sisting of harmonic and Gaussian terms are investigated in the frame of Thomas-Fermi approximation. The depth and the curvature of the potential are changed by varying confinement parameters and the influence of the constraining conditions on the system properties like the density profile, the kinetic and the potential energy of the fermionic system is analyzed comprehensively. The deviations of the results due to the Gaussian potential are also determined by comparing the results with those obtained for pure harmonic potential. Calculations are also performed analytically for non-interacting case for comparative purposes. The results show that the confinement parameters play crucial role on the ground state properties of confined system.Correction Citation - WoS: 1Citation - Scopus: 2Structure Health Monitoring Using Wireless Sensor Networks on Structural Elements (Vol 82, Pg 68, 2019)(Elsevier, 2020-08) Ayyildiz, Cem; Erdem, H. Emre; Dirikgil, Tamer; Dugenci, Oguz; Kocak, Taskin; Altun, Fatih; Gungor, V. CagriArticle Citation - WoS: 263Citation - Scopus: 384Smart Grid Communication and Information Technologies in the Perspective of Industry 4.0: Opportunities and Challenges(Elsevier, 2018-11) Faheem, M.; Shah, S. B. H.; Butt, R. A.; Raza, B.; Anwar, M.; Ashraf, M. W.; Gungor, V. C.The fourth industrial revolution known as Industry 4.0 has paved the way for a systematical deployment of the modernized power grid (PG) to manage continuously growing energy demand by integrating renewable energy resources. In the context of Industry 4.0, a smart grid (SG) by employing advanced Information and Communication Technologies (ICTs), intelligent information processing (IIP) and future-oriented techniques (FoT) allows energy utilities to monitor and control power generation, transmission and distribution processes in more efficient, flexible, reliable, sustainable, decentralized, secure and economic manners. Despite providing immense opportunities, SG has many challenges in the context of Industry 4.0 (I 4.0). To this end, this paper presents a comprehensive presentation on critical smart grid components with international standards and information technologies in the context of Industry 4.0. In addition, this study gives an overview of different smart grid applications, their benefits, characteristics, and requirements. Also, this research investigates and explores different wired and wireless communication technologies used in smart grid with their benefits and characteristics. Finally, this article discusses a number of critical challenges and open issues and future research directions. (C) 2018 Elsevier Inc. All rights reserved.Article Citation - WoS: 24Citation - Scopus: 32Routing Protocol Design Guidelines for Smart Grid Environments(Elsevier, 2014-02) Temel, Samil; Gungor, Vehbi Cagri; Kocak, TaskinThe evaluation of the current electric power grid with novel communication facilities is one of the most challenging and exciting issues of the 21st century. The modern grid technology is called the smart grid in the sense that it utilizes digital communication technologies to monitor and control the grid environments, which ultimately require novel communication techniques to be adapted to the system. Wireless sensor networks (WSN) have. recently been considered as a cost-effective technology for the realization of reliable remote monitoring systems for smart grid. However, problems such as noise, interference and fading in smart grid environments, make reliable and energy-efficient multi-hop routing a difficult task for WSNs in smart grid. Our main goal is to describe advantages and applications of WSNs for smart grid and motivate the research community to further investigate this promising research area. In this study we have investigated and experimented some of the well-known on-demand, table-driven and QoS-aware routing protocols, in terms of packet delivery ratio, end-to-end delay, and energy consumption to show the advantages and disadvantages of each routing protocol type in different smart grid spectrum environments. The environmental characteristics which are based on real-world field tests are injected into ns-2 Network Simulator and the performance of four different multi-hop routing protocols is investigated. Also, we have shown that traditional multi-hop routing protocols cannot deliver adequate performance on smart grid environments. Hence, based on our simulation results, we present some guidelines on how to design routing protocols specifically for smart grid environments. (C) 2013 Elsevier B.V. All rights reserved.Article Citation - WoS: 16Citation - Scopus: 19Recovery of Zinc and Lead from Yahyali Non-Sulphide Flotation Tailing by Sequential Acidic and Sodium Hydroxide Leaching in the Presence of Potassium Sodium Tartrate(Elsevier, 2020-12) Kursunoglu, Sait; Top, Soner; Kaya, MuammerThe recovery of zinc and lead from Yahyali non-sulphide flotation tailing using sulfuric acid followed by sodium hydroxide leaching in the presence of potassium sodium tartrate was experimentally investigated. In the acidic leaching stage, the effects of pH, solid-to-liquid ratio and temperature on the dissolution of zinc from the tailing were explored. 82.3% Zn dissolution was achieved at a pH of 2, a temperature of 40 degrees C, a solid-to-liquid ratio of 20% and a leaching time of 2 h, whereas the iron and lead dissolutions were determined to be less than 0.5%. The sulfuric acid consumption was found to be 110.6 kg/t (dry tailing). The leaching temperature had no beneficial effect on the dissolution of zinc from the tailing. The acidic leach solution was subjected to an electrowinning test. The cathode product consisted of 99.8% Zn and 0.15% Fe. In the alkaline leaching stage, the Pb dissolution increased slightly in the presence of potassium sodium tartrate. More than 60% of Pb was taken into the leach solution when the leaching temperature increased from 40 to 80 degrees C. The final leach residue was analyzed by XRD and XRF. The XRD results indicated that the major peaks originated from the goethite and quartz while minor peaks stem from smithsonite and cemssite. The XRF analysis demonstrated that the residue contained 70.3% iron oxide. Based on the sequential leaching experiments, the zinc and lead were excellently depleted from the flotation tailing, leaving a considerable amount of iron in the final residue.