Gümüşhane ÜniversitesiGümüşhane ÜniversitesiAçık Erişim Arşivi · RDL Open

Sürdürülebilir Kalkınma Amaçları

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  • MakaleYalnız künye2002
    Geothermal energy: Power for a sustainable future

    Kaygusuz, Kamil; Kaygusuz, Abdullah

    This paper discusses the potential and utilization of geothermal energy in Turkey. Geothermal energy for electricity generation has been produced commercially since 1913, and for 4 decades on the scale of hundreds of MW both for electricity generation and direct use. Utilization has increased rapidly during the last 3 decades. In 2000, geothermal resources were identified in over 80 countries, and there are quantified records of geothermal utilization in 58 countries in the world. The worldwide use of geothermal energy amounts to 49 TWh/y of electricity and 53 TWh/y for direct use. On the other hand, Turkey is one of the countries with significant potential in geothermal energy. Resource assessments have been made many times by the Mineral Research and Exploration Directorate (MTA) of Turkey. The main uses of geothermal energy are mostly moderate and low temperature applications such as space heating and domestic hot water supply, greenhouse heating, industrial processes, heat pumps, and electricity generation. The data accumulated since 1962 show that the estimated geothermal power and direct use potential are about 4500 MWe and 31500 MWt, respectively. Present applications have shown that geothermal energy in Turkey and other countries is clean and much cheaper compared to the other fossil and renewable energy sources.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 13 · İklim Eylemi
    İncele
  • MakaleYalnız künye2002
    Comparative study of behavior of reinforced concrete beams strengthened and repaired-strengthened by using V connecting bars and U connecting stirrups

    Öztürk, H.; Ayvaz, Y.

    The purpose of this study is to investigate the repairing and strengthening techniques for reinforced concrete beams and to compare the behaviors of beams strengthened and repaired-strengthened by two different techniques with each other and with the behaviors of monolithic beams. These comparisons are made separately for the load carrying capacity, displacement, ductility, rigidity change, and energy dissipation capacity. The results show that the repairing and strengthening techniques used in this study can be effectively used in the practice.

    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
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  • MakaleYalnız künye2002
    Geothermobarometric investigation of the zigana granitoid, eastern pontides, Turkey

    Karsli, Orhan; Aydi, Faruk; Sadiklar, M. Burhan

    In the Pontides, mineralogically similar, calc-alkaline, zoned I-type granitoids were emplaced into a volcanic-arc environment during the Late Cretaceous and Eocene. The granitoids contain an equilibrium assemblage of quartz, plagioclase, K-feldspar, hornblende, biotite, pyroxene, magnetite, and ilmenite. Large hornblende crystals (1-3 mm) are magnesiohornblende. The average magnesium number is 0.74; Si cation contents range between 6.64 and 7.32; and the average Altot is 0.86. The most common substitution in hornblende is pargasitic. The exchange vector is A□ + VIMg + 2IVSi = ANa + VIAl + 2IVAl. The Altot content of magmatic hornblende in granitoid rocks changes linearly with the crystallization pressures of intrusion; pressures, which were evaluated based on Altot in hornblende, have been estimated using the equation P(kbar) = 4.76Altot - 3.01. The crystallization pressures of granitoid rocks range from 2.4 ± 0.4 to 0.6 ± 0.2 kbar. For estimating temperatures, the hornblende-plagioclase thermometer, T = 0.667P - 48.98 + Y/-0.0429 - 0.008314 InK, was used, and yielded temperatures ranging from 684 ± 13 to 642 ± 7°C. The pressures and temperatures of these zoned intrusions are higher in the granitic and tonalitic rocks of the outer zones than in the quartz monzodioritic and monzonitic rocks of the core.

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  • MakaleYalnız künye1998
    Growth rates of early Campanian rudists in a siliciclastic-calcareous setting (Pontid MTS., North-Central Turkey)

    Steuber, Thomas; Yilmaz, Cemil; Löser, Hannes

    Rudist communities that developed on the southern slope of the Pontid magmatic arc during the late Cretaceous thrived in a tectonically unstable setting, and in environments that were strongly influenced by siliciclastic sedimentation. Strontium isotope stratigraphy indicates an early Campanian age of the investigated association at Höbek Tepe, near Amasya. Stable isotope analyses of sclerochronological profiles of several shells of the three dominating hippuritid species yielded cyclic variations of δ18O that delineate seasonal variations in palaeotemperature. This allowed for the determination of individual life spans, skeletal growth rates and the reconstruction of the living growth fabric. Annual vertical shell growth of 35-40 mm was maintained by cylindrical morphotypes of Vaccinites ultimus during several successive years, while adult annual shell accretion of conical morphotypes was only 27 to 30 mm. Vertical growth of the co-occurring Yvaniella alpani was considerably slower and rarely exceeded 10mm/year. Differential growth rates of the two most abundant species, and morphological characters of Yvaniella which indicate that skeletal growth capacity was similar to sediment accumulation, allowed for a consistent reconstruction of the original growth fabric. CaCO3 production of the rudist communities amounted to 20 kg x year-1 x m-2 and contributed significantly to the sedimentary budget. Large-scale formation of fine-grained calcareous sediments by bioeroders occurred only in environments of less rapid burial, indicated by associations of slowly-growing geniculate rudist morphotypes and patellate corals. The implications of these results for the distribution of rudists and corals in Cretaceous shallow-marine environments are discussed.

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