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Yayın The composition of acids in bitumen and in products from saponification of kerogen: Investigation of their role as connecting kerogen and mineral matrix(Elsevier Science BV, 2008-11-03) Razvigorova, Maria; Budinova, Temenuzhka K.; Tsyntsarski, Boyko G.; Petrova, Bilyana N.; Ekinci, Ekrem; Atakül, HüsnüIn order to obtain more information and to understand the nature of relation between organic and mineral matter in oil shales, the compositions of soluble bitumen fractions obtained by extraction from Bulgarian oil shales before and after demineralization with 10% HCl, concentrated HE and a HF/HCl mixture were investigated. The four extracts were quantitatively examined by IR and H-1 NMR spectroscopy. The investigation of isolated acidic material of the bitumen fractions showed that the fatty acids are present in bitumen fractions as free acids, esters and salts. The amount of free acids in bitumen is very small. The dominant part of bitumen acids is associated with mineral components of the oil shales as well as part of them is included in the mineral matrix, and can be separated only after deep demineralization. The kerogen of the oil shales, obtained after separation of the bitumen fractions and mineral components, was subjected to saponification in order to determine the amount of acids, bound as esters to the kerogen matrix. The major components found were n-carboxylic, alpha,omega,-di-carboxylic, and aromatic acids. The connection of kerogen with mineral components is accomplished by the participation of carboxylic and complicated ester bonds. Experimental data for the composition of bitumen acids give evidence that algae and terrestrial materials are initial sources in the formation of soluble organic matter of Bulgarian oil shale.Yayın The emergence of projected scaled patterns of extreme temperatures over Europe(Frontiers Media SA, 2023-06-28) Öztürk, Tuğba; Canbaz, Emine; Bilgin, Başak; Matte, Dominic; Kurnaz, Mehmet Levent; Christensen, Jens HesselbjergThis work investigates the scalability of extreme temperatures over the European domain with global warming levels. We have used the EURO-CORDEX ensemble of regional model simulations at 0.11° resolution for daily minimum and maximum temperatures to analyze future changes in extreme weather daily events. Scaling with the annual mean global warming modeled by the driving GCM was applied to future extreme temperature indices changes. Regional changes in each index were scaled by corresponding global warming levels obtained from GCMs. This approach asserts that regional patterns of climate change and average global temperature change are linearly related. It can provide information regarding climate change for periods or emission scenarios when no simulations exist. According to the results, the annual minimum of the lowest temperature of the day (TNn) increases more than the annual maximum of the highest temperature of the day (TXx) for Europe. The multi-model mean of the changes in scaled patterns of extreme temperatures emerges early, around 2020, even before it becomes robust. Individual scaled patterns of TNn and TXx emerge from around 2040.Yayın Energy harvesting cooperative multiple access channel with decoding costs(IEEE, 2016) Arafa, Ahmed M.; Kaya, Onur; Ulukuş, ŞennurWe consider an energy harvesting cooperative multiple access channel (AC) with decoding costs. In this setting, users cooperate at the physical layer (data cooperation) in order to increase the achievable rates. Data cooperation comes at the expense of decoding costs: each user spends some amount of its harvested energy to decode the message of the other user, before forwarding both messages to the receiver. The decoding power spent is an increasing convex function of the incoming message rate. We characterize the optimal power scheduling policies that achieve the boundary of the maximum departure region subject to energy causality constraints and decoding costs by using a generalized water-filling algorithm.Yayın From conflict to cooperation: Desecuritization of Turkey's relations with Syria and Iran(Sage Publications Ltd, 2008-10) Aras, Bülent; Karakaya Polat, RabiaIn recent years, there has been a notable softening in Turkey's foreign policy toward Syria and Iran. How might we explain the change in Turkey's attitude toward these two countries considering the hostile relations of the 1990s and the worsening security situation in the Middle East? Drawing upon securitization theory, this article argues that domestic problems have influenced Turkey's foreign policy toward Iran and Syria in the past, as foreign policymakers have successfully externalized the sources of political Islam and Kurdish separatism. The remarkable softening of Turkey's foreign policy toward Syria and Iran since the beginning of the present decade can best be explained by looking at changes at the domestic level, particularly in terms of the process of desecuritization currently taking place within Turkey. Among other things, this process of desecuritization is the result of the European Union accession process and concomitant steps toward democratization, a transformation of the political landscape, and the appropriation of EU norms and principles in regional politics. Within this process of desecuritization and democratization, formerly securitized and dramatized issues have begun to be perceived as normal political issues. As a result, the policymaking process is now emancipated from ideational barriers, while there has been a substantial increase in the flexibility of foreign policy attitudes and the ability of foreign policymakers to maneuver in regional policy.Yayın Simulation of temperature and precipitation climatology for the Central Asia CORDEX domain using RegCM 4.0(Inter-Research, 2012) Öztürk, Tuğba; Altınsoy, Hamza; Türkeş, Murat; Kurnaz, Mehmet LeventThe Coordinated Regional Climate Downscaling Experiment (CORDEX) is a framework designed to coordinate international efforts on regional climate simulations. CORDEX domains encompass the majority of land areas of the world. Region 8 of the CORDEX basically covers Central Asia, with the corners of the domain at 54.76 degrees N, 11.05 degrees E; 56.48 degrees N, 139.13 degrees E; 18.34 degrees N, 42.41 degrees E; and 19.39 degrees N, 108.44 degrees E and with a horizontal resolution of 50 km. In the present study, the results of an experiment with the ICTP regional climate RegCM 4.0 model that was run for seasonal mean air temperature and precipitation total series are presented. The experiment consists of one simulation from 1989 to 2010 using ERA-Interim reanalysis data as the boundary condition, another simulation for the period 1970-2000 using the global climate model ECHAM5 A1B scenario data for forcing, and finally a simulation for the period 2070-2100 using the ECHAM5 A1B scenario projection data for forcing. Between these 3 simulations we determined the temperature and precipitation climatology obtained from RegCM 4.0 downscaling for Region 8 of the CORDEX framework. In spite of the diverse topography of the region, the temperature and precipitation climatology obtained by RegCM 4.0 from hindcast data captures the general characteristics of the climate of Central Asia. In winter, the warm temperature bias of the forcing data is slightly decreased by regional downscaling. The influences of the Indian monsoon system are well represented, as this region covers a large area towards the southern boundary of Region 8, even though the focus of this work was to capture the general characteristics of the whole region.Yayın Driving forces of Turkey's transportation sector CO2 emissions: An LMDI approach(Elsevier Ltd, 2020-08-01) Işık, Mine; Sarıca, Kemal; Ari, İzzetThe transportation sector is one of the main contributors to global greenhouse gas (GHG) emissions. As the efforts towards emission mitigation increase, the expectation from the sector arises equally. In this analysis, the transportation sector of Turkey is studied to shed light on the future based on historical realizations. In this respect, the Logarithmic Mean Divisia Index (LMDI) method is used to assess and reveal the influential factors on CO2 emissions in the sector between 2000 and 2017. The emission intensity of the sector and fuel switching shows promising trends from 2000 through 2010, whereas growing preference for SUVs challenges emission reductions between 2010 and 2017. The results indicate that i) The transportation sector CO2 emissions are mainly driven upwards by economic growth, followed by population and emission intensity effects from 2000 to 2017 ii) The overall impact of transportation intensity shows significant reduction potential iii) Fuel switching incentives and fleet efficiency have a positive effect on emission mitigation from 2000 through 2010. However, this gain is reduced due to the rising popularity of SUVs in the rest of the analysis period. In this respect, CO2 emission mitigation in the transportation sector necessitates 1) careful planning of demand management for freight transportation including master designs production/manufacturing sites, material flows, and demand points coupled with economic activities 2) passenger transportation measures to reduce passenger car travel including zoning for public transit corridors, improved public transportation system 3) well-structured incentives on energy-efficient cars and clean energy technologies such as electric vehicles to convince individuals. Analysis can be generalized on a global scale due to the similar dynamics inherent in the sector.Yayın Countering insurgency: Turkey's policy toward the PKK's transnational dynamics in Europe(Routledge Journals, Taylor & Francis Ltd, 2018-01-02) Kayhan Pusane, Özlem; Ilgıt, AslıInsurgents often develop international connections and benefit from external assistance from a variety of sources. Support from diaspora communities has long been considered one of the critical external factors in the persistence of insurgent groups. Yet how the counterinsurgent state addresses external support from transnational ethnic communities and what factors influence the state's policies remain understudied. By focusing on the transnational political practices of the Kurdish community and the PKK in Western Europe, this paper examines how Turkey has addressed the diasporic support for the PKK since the 1980s. It shows that three major factors - the composition of foreign policy decision-makers, their ideological contestation over the Kurdish question, and the European political context - have affected Turkey's policy regarding the PKK's transnational dynamics in Europe.
