Gümüşhane ÜniversitesiGümüşhane ÜniversitesiAçık Erişim Arşivi · RDL Open

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  • BildiriYalnız künye2007
    Environmental pollution originated from open dumping of solid waste in the cities of Eastern Black Sea

    Ersoy, H.; Ersoy, A. Firat; Dag, S.; Berkün, M.

    İncele
  • BildiriYalnız künye2007
    Sizing of a spherical shell as variable thickness under dynamicloads

    Asçi, Nurcan; Uysal, Habib; Uzman, Omit; Inan, E; Kiris, A

    In this paper, optimization of a spherical shell under various dynamic loads is investigated. The aim of this optimization problem is to minimize the volume of the shell. Design variables are corner thicknesses of each finite element. Constraints are stresses obtained from von Mises stress criterion not to exceed the yield stress in corner nodal points of each finite element at the top and bottom surfaces of shell and thicknesses are restricted not to be less than 2.5 mm. In addition to shell's own weight, the vertical loads with equal intensity are applied at the nodal points on the upper edge of spherical shell, varying with respect to time function P(t). Time varying load vector is considered three different cases such as step, step after ramp and impulse functions. A program is coded with MapleV for optimization of spherical shell and finite element package program ANSYS is used for structural analysis. Obtained results are presented in graphical and tabular form. Finally, concluded remarks are given.

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  • MakaleYalnız künye2007
    Mid-Cretaceous olistostromal ophiolitic mélange developed in the back-arc basin of the eastern Pontide magmatic arc, northeast Turkey

    Eyuboglu, Yener; Bektas, Osman; Pul, Dilek

    Geological and geochemical characteristics of the Mid-Cretaceous olistostromal ophiolitic mélange exposed in the southern part of the eastern Pontide magmatic arc indicates that it originally formed during the drifting stage of a back-arc basin (Neotethys). This view conflicts with the popular idea that this ophiolitic mélange represents a typical tectonic mélange or an accretionary prism developed in the fore-arc of the eastern Pontide magmatic arc by northward subduction of Neotethys or Paleotethys during the Cretaceous. This Mid-Cretaceous ophiolitic mélange is composed of the three distinct lithological facies that may reflect a strike-slip cycle - from transtensional to transpressive tectonic regimes - in the deep spreading troughs of pull-apart basins. The lower part of the mélange is represented by redeposited carbonate rocks that occur as an upward thinning and fining sequence. The middle level of the melange comprises basaltic pillow lavas, hyaloclastics, and intercalated pelagic sediments such as radiolarite, mudstone, and red pelagic limestone. The upper part of the mélange is represented by an olistolith-olistostromal facies that includes sandstone, siltstone, marl, and intervening olistoliths and olistostromes - mainly limestone, peridotite-gabbro, and metamorphic blocks derived from the continental shelf and a nearby peridotitic-metamorphic ridge. Trace-element and REE contents of the basaltic rocks belonging to the Mid-Cretaceous ophiolitic mélange show distinct geotectonic settings (IA, WP, MOR) with various enrichment and depletion trends with respect to MORB and chondrite. Moreover, this ophiolitic mélange is overlain by analcime-bearing Upper Cretaceous-Paleocene(?) shoshonitic basalts in the Bayburt-Maden area. These geological and geochemical data imply that mélange formed in the back-arc basin of the eastern Pontide magmatic are.

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  • MakaleYalnız künye2007
    Different modes of stress transfer in a strike-slip fault zone: An example from the North Anatolian Fault System in Turkey

    Bektaş, Osman; Eyüboǧlu, Yener; Maden, Nafiz

    The dextral North Anatolian Fault System (NAFS) extends for well over 1000 km from the compressive tectonic domain of eastern Anatolia into the broad and diverse tectonic domain of the western Anatolian, Marmara and Aegean regions. These different tectonic regimes are characterized by a narrow deformation zone in the east and a much broader deformation zone with multiple sub-parallel fault zones in the west. The spatial and temporal distribution of large historical and modern earthquakes (Mw>5) shows two distinctive macro-seismic zones in the eastern and western parts of the NAFS. The eastern macro-seismic zone, between the towns of Erzincan and Bolu, has produced a successive linear earthquake series parallel to the fault system over the last 500 years, suggesting that stress transfer along the fault occurred in a manner of 'Static Coulomb failure stress changes' through the entire elastic crust. In contrast, the western macro-seismic zone of the NAFS, in the Marmara region, has produced successive earthquake pairs on the parallel faults, implying 'dynamic stress changes', involving large-scale flow in the aseismic lower crust and the mantle.

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  • MakaleYalnız künye2007
    The magnetic susceptibility of granitic rocks as a proxy for geochemical composition: Example from the Saruhan granitoids, NE Turkey

    Aydin, Ali; Ferré, Eric C.; Aslan, Zafer

    The magnetic susceptibility of rocks is determined by their bulk chemistry and magnetic mineralogy. In this case study of the Saruhan pluton in Turkey, a detailed survey based on 925 field measurements and 37 whole rock analyses, reveals a strong correlation between magnetic susceptibility and FeOt (R2 = 0.8). Petrographic observations and calculations based on whole-rock major element analyses indicate the presence of magnetite grains. Further calculations show that magnetite accounts for 88% of the magnetic susceptibility. The spatial correlation between FeOtotal and the magnetic susceptibility is particularly spectacular which suggests that Km is a proxy for geochemical differentiation. The zoning pattern of magnetic susceptibility across the pluton is concentric and reverse, with the highest values of magnetic susceptibility in the center. This type of zoning is consistent with a previously proposed petrogenetic model. The comparison of the Saruhan granites with a classic example of paramagnetic granites reveals two contrasted FeOt-Km trends. This suggests that these variations can be a useful tool to distinguish between leucocratic paramagnetic and leucocratic ferrimagnetic granites.

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  • MakaleYalnız künye2007
    Optimum shape design of shell structures

    Uysal, Habib; Gul, Rustem; Uzman, Umit

    A finite element-based shape optimization program has been developed for three-dimensional shell structures and the shape optimization of shell structures has been performed. The shape optimization program is implemented by a job control language and a reliable finite element package program, ANSYS, is used for structural analysis. To achieve the shape optimization, different principles such as structural analysis, automatic mesh generation, sensitivity analysis and mathematical programming are inter-related. The objective is to minimize the weight of the shell structure under constraints that are the maximum value of the von Mises stress in each element and the move limit for each design variable. The design sensitivities are calculated using the finite difference method. The search for the final shape of a structure is performed using the linear programming technique. Several examples are provided.

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  • MakaleYalnız künye2006
    Effects of feeding acidified milk replacer on the growth, health and behavioural characteristics of holstein Friesian calves

    Yanar, Mete; Güler, Olcay; Bayram, Bahri; Metin, Jale

    The objective of this study was to compare the performances of calves fed acidified milk replacer (AMR) or sweet (regular) milk replacer (SMR) at 8% of birth weight. Twenty- one calves (10 males, 11 females) were offered replacers reconstituted to 12% of dry matter over 5 weeks. In the group fed AMR, daily body weight gains of calves at the different stages of growth were comparable to those for calves fed SMR. In the preweaning period, calves offered AMR had similar dry matter intakes from starter, milk replacer and dry hay as well as total intake as those fed SMR. In the postweaning phase, total dry matter intakes of calves offered AMR and SMR were not statistically different. The overall feed efficiency ratios of AMR- fed calves were better (P < 0.05) than those of SMR- fed calves. Calf faecal consistency score (P < 0.05) and percent days with scours (P < 0.01) of calves offered AMR were significantly lower than those fed SMR for days 4 to 17. AMR-fed calves needed a longer time (P < 0.01) to consume the daily amount of replacer than SMR- fed calves. The calves fed AMR also took a significantly (P < 0.05) greater number of days to learn to drink milk replacer from an open pail without help than calves consuming SMR. In conclusion, it is suggested that the growth performance and feed efficiency characteristics of calves reared under the new feeding system with AMR were not adversely affected, but the incidence of scours of the young calves was dramatically reduced.

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  • MakaleYalnız künye2006
    Performance and health of dairy calves fed limited amounts of acidified milk replacer

    Güler, O.; Yanar, M.; Bayram, B.; Metin, J.

    To compare growth performance of Brown Swiss calves fed acidified milk replacer (AMR) at 8% of birth weight, 20 newborn calves were reared under a new calf-feeding programme. Body weights, total weight gains and gains in body measurements, feed intake and feed efficiency values determined at different stages of growth of AMR-fed calves were comparable to those of calves fed sweet milk replacer (SMR). Faecal consistency scores and percent days with diarrhoea of calves offered AMR from four to 35 days of age were respectively 0.4 and 19.1% lower than those fed SMR. Most of the bebavioural parameters studied were not unfavourably influenced by acidification of the replacer. In conclusion, growth, feed intake and feed efficiency characteristics of Brown Swiss calves fed AMR or SMR were not different from each other. However, incidence of diarrhoea of the young calves was decreased and health status of the calves was improved with the feeding of acidified milk.

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  • MakaleYalnız künye2006
    Geochemical constraints on the provenance, mineral sorting and subaerial weathering of Lower Jurassic and Upper Cretaceous clastic rocks of the eastern Pontides, Yusufeli (Artvin), NE Turkey

    Dokuz, Abdurrahman; Tanyolu, Erkan

    An integrated petrographic and geochemical study of the shales and sandstones of Early Jurassic and Late Cretaceous age in the Yusufeli area (Turkey) was carried out to obtain more information on their provenance, sedimentological history and tectonic setting, as well as to evaluate the influence of weathering, hydraulic sorting and recycling processes upon source-rock signature. Depending on their matrix and mineralogical content the Lower Jurassic sandstones are identified as arkosic arenite and wacke, while the Upper Cretaceous sandstones are defined as lithic arenite and wacke. Elemental ratios such as La/Sc, Cr /Ni, Co/Th, Th/Sc and Cr/Th indicate a mafic source for the marjority of each of the sandstone sequences. However, in several samples, high Th/Sc and low Cr/Th ratios suggest a contribution from a felsic source. Using element-ratio diagrams, all of the samples plot along a curve consistent with a two-component mixing model, consisting of a dominant mafic and a subordinate felsic source. The relatively low Cr/Ni ratios provide no support for significant amounts of ultramafic lithologies in the source area. The lower trace-element contents of the studied sandstones in relation to post-Archean Australian shales (PAAS), which are representative of the composition of the upper continental crust, indicate that recycling processes in their source areas were probably less intense than those of the PAAS. The more LREE-depleted patterns of the shales relative to sandstones likely do not reflect changes in source-area composition but, rather, variations in mineral sorting, chemical weathering and/or sediment recycling. Chemical index of alteration (CIA) indices observed in the Lower Jurassic and Upper Cretaceous sediments (average of 53 & 46, respectively) suggest that their source area underwent moderate degrees of chemical weathering processes. However, an upward increase in the values of the CIA indices in the Lower Jurassic profiles may indicate that the source area gradually underwent more intense chemical weathering, possibly due to climatic and/or tectonic variations. On the other hand, an upward decrease in the CIA indices of the Upper Cretaceous profiles generally demonstrate that the sediments were derived from a relatively less-weathered source terrain, reflecting an increased erosion rate likely due to increasing tectonic activity. The compositional immaturity of the analysed sandstone samples is typical of subduction-related environments, and their SiO2/Al2O3 and K2O/Na2O ratios and Co, Sc, Th and Zr contents reflect their oceanic and continental-arc settings.

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  • MakaleYalnız künye2006
    Traditional wooden buildings and their damages during earthquakes in Turkey

    Doǧangün, Adem; Tuluk, Ö.Iskender; Livaoǧlu, Ramazan; Acar, Ramazan

    Wood is one of the oldest structural materials used in structures in many parts of the World. Woodframe buildings were also commonly constructed in Turkey until approximately 1960. After that, as reinforced concrete and masonry buildings have been preferred, wooden buildings have almost been forgotten. But, in 1999, Kocaeli and Duzce earthquakes reminded traditional buildings. Since reinforced concrete buildings presented high level of damage and traditional buildings relatively performed well during these earthquakes. In this study, types of traditional wooden buildings used in Turkey are mainly introduced and their damages in earthquakes are discussed. Damaged and undamaged wooden building photos are illustrated. Some structural weaknesses are highlighted by the earthquake damages including cracking and falling of plaster, failure of mortar, loosening or failing of connections, large lateral displacements, dislodgement of the masonry infill, loosening or failing of connections and failure of connections to foundation.

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  • MakaleYalnız künye2006
    Mineralogy, petrography and whole-rock geochemistry of the Tertiary granitic intrusions in the Eastern Pontides, Turkey

    Arslan, M.; Aslan, Z.

    Granitic intrusions in Eocene and post-Eocene volcanic rocks outcrop in the Northern and Southern Zones of the Eastern Pontides, NE Turkey. Intrusions in the Northern Zone extend NW-SE whereas those in the Southern Zone are nearly E-W orientated. The contacts of the intrusions with the volcanic rocks are sharp, epidotized and include volcanic xenoliths. The margins of Southern Zone intrusions often contain abundant angular mafic microgranular enclaves of diorite to quartz diorite composition. The rocks also show evidence of mingling and mixing between coeval mafic and felsic magmas. Field observations suggest a stopping type of ascent and emplacement style for the intrusions. Petrographically, intrusions show variations in both colour and mineralogy with fine to medium granular, monzonitic, poikilitic, rapakivi, anti-rapakivi and graphic textures. Based on modal mineralogy, the Northern rocks are monzonite, quartz monzonite, monzodiorite and quartz monzodiorite whereas the Southern samples are monzogranite and granodiorite. The rocks are generally calc-alkaline to mildly alkaline transitional and metaluminous, and show a CAFEMIC trend. The Northern Zone intrusions form a post-collisional, A-type, alkaline monzonitic association and Southern Zone intrusions form a post-collisional, I-type, granodioritic calc-alkaline-transitional association. Whole-rock compositional data indicate that differentiation occurred via fractional crystallisation with or without magma mixing. Incompatible and rare earth element patterns indicate that both the Northern and the Southern Zone intrusions were derived from melting of a mantle region enriched by subduction-related fluids but evolved differently during ascent and emplacement. U-Pb zircon dating in the Southern Zone yields an intrusion age of 44.4±0.3 Ma. Regional geodynamics indicates post-collisional extensional tectonics in the region. Crustal involvement and the level of emplacement may have been important for magmatic evolution, especially for the Southern Zone intrusions, after the cessation of subduction and subsequent crustal thickening.

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  • MakaleYalnız künye2006
    Three-directional extensional deformation and formation of the Liassic rift basins in the Eastern Pontides (NE Turkey)

    Eyüboǧlu, Yener; Bektaş, Osman; Şeren, Aysel; Maden, Nafiz; Özer, Rahşan; Jacoby, Wolfgang R.

    The Eastern Pontide magmatic arc (NE Turkey) was rifted by the polyphase extensional tectonic regimes in the Early Jurassic. While alternated volcanics and siliciclastic sedimentary rocks accumulated during the episodic tectonic subsidences, thermal subsidence is manifested by sedimentation of the red pelagic limestones of the Ammonitico Rosso during the Pliensbachian. The trends of the Liassic basins extending in NW-SE, E-W, NE-SW directions coincide with the gravity and magnetic lineament anomalies and corresponding fault zones that are responsible for the paleotectonic and neotectonic evolutions of the Eastern Pontide magmatic arc. These mutual relationships suggest that the faults making up the architecture of the Liassic basins might have operated during the Paleozoic, Mesozoic and Cenozoic times in different manners. Neptunian dikes, filled by the early rift siliciclastic and following fossiliferous red pelagic limestone implying the repeated extensional tectonic regimes, are also parallel to the main extensions of the Liassic basins. The poles of the contemporaneous neptunian dikes suggesting two or three extensional conjugate fracture systems are in accordance with the dip directions of the rift sediments accumulated in the same conjugate normal fault systems. Assuming that the Liassic basins with Ammonitico Rosso are coeval, multi-armed rift basins might have opened by the mode of the three-directional extension rather than reactivation of faults in the different times.

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  • BildiriYalnız künye2006
    Is postprandial 2h glucose level a real determinant for glucose intolerance in people at risk for type 2 diabetes? RISK study results - I

    Yilmaz, T.; Sargin, M.; Olmez, B.; Karadeniz, S.; Oguzhan, B.

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  • BildiriYalnız künye2005
    Hornblende and phlogopite-bearing ultramafic cumulates: Evidence for subduction-related ultramafic magmatism in the Eastern Pontides, Amasya area, NE Turkey

    Eyuboglu, Y; Bektas, O; Sen, C

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  • MakaleYalnız künye2005
    The protective role of erdosteine on testicular tissue after testicular torsion and detorsion

    Koc, A; Narci, A; Duru, M; Gergerlioglu, HS; Akaydin, Y; Sogut, S

    Testicular torsion and detorsion are important clinical problems for infertile man and oxidative stress may have a role in this clinical situation. The aim of this study was to investigate the protective role of erdosteine, an antioxidant, on unilateral testicular reperfusion injury in rats. The rats were divided into four groups including seven rats in each group: control, torsion, torsion/detorsion and torsion/detorsion+erdosteine. Rats, except the sham operation group, were subjected to left unilateral torsion (720 degrees rotation in the clockwise direction) without including the epididymis. The experiments were finished after sham operation time for control, 120 min torsion for torsion group and 120 min torsion and 240 min detorsion for torsion/detorsion groups. Bilateral orchiectomy was performed for all groups of rats. The ipsilateral and controlateral testis were divided into two pieces to analyse biochemical parameters and to investigate the light microscopic view. Malondialdehyde level of ipsilateral testis was increased in torsion and torsion/detorsion groups in comparison with the other groups (p < 0.05). Erdosteine treatment ameliorated lipid peroxidation after torsion/detorsion in ipsilateral testis (p < 0.05). Also, xanthine oxidase activity of ipsilateral testis was increased in torsion/detorsion group in comparison with the others (p < 0.05). Nitric oxide (NO) level of ipsilateral testis was higher in all experimental groups than sham operated control group (p < 0.05). Also, NO level of torsion group was increased in comparison with detorsion groups (p < 0.05). Erdosteine treatment caused increased glutathione peroxidase activity in comparison with torsion and torsion/detorsion groups and catalase activity in comparison with the other groups in ipsilateral testis (p < 0.05). Superoxide dismutase activity of ipsilateral testis was higher in torsion/detorsion and torsion/detorsion+erdosteine groups than control and torsion groups (p < 0.05). The biochemical parameters were not affected in controlateral testis in all groups. Torsion, torsion/detorsion and torsion/detorsion+erdosteine groups showed ipsilateral testicular damage in the histological examination, but the specimens from torsion/detorsion had a significantly greater histological injury than those from the other groups (p < 0.05). Control rats showed normal seminiferous tubule morphology. Rats in torsion group had slight-to-moderate disruption of the seminiferous epithelium. Rats in torsion/detorsion group displayed moderate-to-severe disruption of the seminiferous epithelium. In all animals from torsion/detorsion+erdosteine group, the testicular tissues were affected with slight-to-moderate degenerative changes of the seminiferous epithelium. Administration of erdosteine resulted in a significantly reduced histological damage associated with torsion of the spermatic cord compared with torsion/detorsion. In all groups, the contralateral testes were histologically normal. In conclusion, the results clearly displayed that erdosteine treatment may have a protective role on testicular torsion/detorsion injury.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
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  • MakaleYalnız künye2004
    Energy and sustainable development. Part II: Environmental impacts of energy use

    Kaygusuz, Kamil; Kaygusuz, Abdullah

    As a consequence of the fast-growing energy requirements and the increasing use of low-grade domestic fuels, air pollution has increased considerably in recent years in Turkey. Since the energy demand is projected to continue to increase rapidly in the future also, energy-supply strategies are required to control air-pollutant emissions in a cost-efficient way, taking into account the legal emission-control regulations that have been enforced. This article extensively concentrates on energy and environmental impacts in Turkey only. Energy utilization and its major environmental impacts are discussed from the standpoint of sustainable development, including anticipated patterns of future energy use and subsequent environmental issues. Several aspects relating to energy utilization, renewable energy, energy efficiency, environment, and sustainable development are examined from both current and future perspectives in the country. In this study, air-pollutant emissions due to power generation and their harmful effects on the environment are also estimated.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 12 · Sorumlu Üretim ve Tüketim
    • SDG 13 · İklim Eylemi
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  • MakaleYalnız künye2002
    Energy and sustainable development in Turkey. Part I: Energy utilization and sustainability

    Kaygusuz, K; Kaygusuz, A

    Turkey is an energy importing country; more than half of the energy requirement has been supplied by imports. Domestic oil and lignite reserves are limited, and lignites are characterized by high ash, sulfur and moisture content. In this regard, renewable energy resources appear to be one of the most efficient and effective solutions for sustainable energy development in Turkey. Turkey's geographical location has several advantages for extensive use of most of these renewable energy sources. Because of this and the fact that it has limited fossil fuel resources, a gradual shift from fossil fuels to renewables seems to be serious and the sole alternative for Turkey. This article presents a review of the present energy situation and sustainability, technical and economical potential of renewable energy sources, and future policies for the energy, sector in Turkey. Throughout this paper several problems relating to energy sources and sustainable development are discussed from both current and future perspectives.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
    • SDG 12 · Sorumlu Üretim ve Tüketim
    • SDG 13 · İklim Eylemi
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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
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