Palandöken Dağının Atmosferik Özellikleri

Erzurum şehir merkezine çok yakın bir konumda olan Palandöken Dağı, 3175 m yüksekliğiyle Türkiye’deki ve Dünya’daki en önemli (stratejik, sportif, turistik vb.) zirvelerden birisidir. Palandöken Dağı ve çevresinin fiziki, stratejik ve atmosferik koşullarının farklı amaçlarla kullanılabilirliğinin (alternatif enerji kaynakları potansiyelinin belirlenmesi ve enerji üretimi ve teknolojileri, turistik ve sportif faaliyetlerde, kar - su hidrolojisi, bilimsel alanlarda vb.) artırılması, bölgenin ve zirvenin atmosferik haritasının tam olarak çıkarılması ve ayrıca 2011 yılında Erzurum Palandöken Dağı ve çevresinde yapılacak olan Üniversite Kış Oyunları içinde gereken, zirve ve çevresinin temel meteorolojik özelliklerinin ayrıntılı olarak ortaya çıkarılması amacıyla bir bilimsel araştırma projesi kapsamında, yaklaşık 1 yıldır meteorolojik veriler sürekli kaydedilmekte ve incelenmektedir. Bu bilgiler, Bölge Meteoroloji Müdürlüğü’nden alınan meteorolojik yer ve radyosonda verileriyle de karşılaştırılmaktadır. Bu proje kapsamına, yeni başlatılan atmosferik görüş gözlemleri de dahil edilmiştir. Ayrıca bu çalışma ve sonuçları sayesinde, Palandöken Dağı ve çevresindeki yakın zirvelerinde (> 3000 m) meteorolojik özellikleri belirleneceği gibi, yeni yapılmaya başlayan ve devam edecek olan atmosferik ve astronomik diğer testler ile bölgenin temel astronomik özellikleriyle birlikte astronomi konusundaki potansiyeli de ortaya çıkarılmış olacaktır. Bu çalışma, Atatürk Üniversitesi, FenEdebiyat Fakültesi, Fizik Bölümü tarafından yürütülmekte (2007-2008) ve Atatürk Üniversitesi tarafından Bilimsel Araştırma Projesi (BAP - 2007/33) olarak desteklenmektedir

COMPOSITION AND GENESIS OF THE NICKEL-CHROME-BEARING NONTRONITE AND MONTMORILLONITE IN LATERITIZED ULTRAMAFIC ROCKS IN THE MURATDAGI REGION (USAK, WESTERN ANATOLIA), TURKEY

Widespread lateritized ultramafic rocks in the southern part of the Muratdagi region of Turkey constitute a significant source of Ni-Cr-bearing ore with economic potential. However, no mineralogical or geochemical characterizations of these important materials have been performed previously. The aim of the present study was to describe the mineralogy, geochemistry, and genesis of Ni-Cr-bearing smectite in garnierite and ferruginous saprolite associated with the lateritized ophiolite-related ultramafic rocks. The lateritic zones are well developed over serpentinized harzburgitic mantle peridotites. The lateritized units and related bedrocks were examined using polarized-light microscopy, X-ray diffraction, scanning and transmission electron microscopies, and chemical and isotopic methods. The garnierite-containing saprolites are enriched in smectite, Fe-(oxyhydr)oxide phases, and opal-CT. Micromorphological images revealed that flaky smectite and, locally, Fe-rich particles, alunite, gypsum, gibbsite, and sulfur crystals developed along the fractures and dissolution voids. The development of saprolite demonstrates chemical weathering. The presence of silicified and Fe-(oxyhydr)oxide phases associated with gypsum, alunite, and local native sulfur in vertical and/or subvertical fractures and fault infillings are indicative of hydrothermal processes along the extensional, tectonically related fault systems. Chemical weathering and hydrothermal processes, which probably started during the Oligocene and Miocene, led to the formation of nontronite, Fe-bearing montmorillonite, and local Fe-rich kaolinite. Nickel and Cr are concentrated significantly in the saprolite zone and are positively correlated with Fe2O3 content, which is controlled by the formation of nontronite, montmorillonite, and Fe-(oxyhydr)oxide phases. Nickel-Cr-bearing nontronite and montmorillonite precipitated from alkaline water as a result of the increasing (Fe2O3+Al2O3+Cr2O5+Ni+Co)/(MgO+SiO2) ratio under the control of both chemical weathering and hydrothermal processes. The Fe and Mg (associated with Ni and Cr) required for the formation of smectite were supplied by solutions from both chemical weathering and hydrothermal alteration of Ni-Cr-bearing olivine and pyroxene in the harzburgitic bedrock; the Al was supplied by schists, granite, and volcanic units

Optimization and mathematical modeling of mass transfer between Zostera marina residues and supercritical CO2 modified with ethanol

Supercritical CO2 extraction of phenolic compounds from Zostera marina residues was optimized by developing a mathematical model based on mass transfer balances. A linear driving force model was applied considering model parameters such as solute concentration on the surface of the solid (Cs) and in the supercritical fluid phase (Cf), film mass transfer coefficient (kf) and molecular diffusivity (DAB) and axial dispersion (Dax) coefficients. Henry's law was used to describe the equilibrium state of solid and fluid phases. The results of the proposed model were compared to that of the experimental data in terms of transport properties and extraction yield at various temperatures (303.15, 323.15, 353.15 K), pressures (15, 25, 35 MPa) and co-solvent mass ratios (0, 10, 20%). The optimum parameters were elicited as 25 MPa, 353.15 K and a co-solvent ratio of 20% yielding 77.22 μg g−1 dry feed. The model satisfactorily described the extraction yield which can be used for scale-up purposes