Wyniki wyszukiwania - BazTech

1

The effect of nut shell addition on the permeability of a crushed gold ore

Yilmaz S., Sirkeci A. A., Bilen M., Yigit I., Kizgut S.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 2

467--475

EN

In this study, variations in permeability of a gold ore by nut shell addition was studied. Ore particle size, nut shell size and volume fraction in the ore were the parameters investigated. Permeability is an important issue in heap leach operations considering the processing duration. Particularly below 6 mm particle size permeability is greatly hampered. Turkey is the leading country in the world in hazelnut production. Therefore, considerable amounts of nut shell are obtained as a by-product. Incerase in the permeability of a finely crushed ore will obviously enable an increase in the leaching efficiency. The finer the particle size the more the liberation of gold is yet the permeability is lower. Therefore, this study focuses on the possibility of improving the permeability of ore heaps with nut shell addition. Optimum amount of nut shell which should be added to the ore was found to be 5% by volume. It was found that the permeability of ore crushed below 2.36 mm considerably increased by the addition of nut shell below 18 mm.

2

Friction and Wear Properties of Plasma Sprayed YSZ/Ni-Cr-Al Coated 6063-T6 Aluminum Alloy

Erzi E., Dispinar D., Yilmaz S.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 3

168--174

EN

In this study T6 heat treated 6063 aluminum alloys were used as substrate material. In order to form a bond between the substrate and the main coating, all samples were coated with Ni-Cr-Al powders. 8 wt% Yttria Stabilized Zirconia powders (YSZ) were coated with plasma spray technique. Thickness of YSZ was 150 m and bond coating was 36 m. XRD and SEM-EDS analyses were performed to characterize the coating layers. These YSZ coated and uncoated samples were subjected to wear testing under different spindle speed, loading and working distance. Wear test results were compared with the kinetic friction coefficients and weight loss values. Wear marks on YSZ coated and uncoated samples were investigated by SEM analysis. By coating with plasma spray technique, the wear resistance of Al alloys was increased without changing the friction coefficient. It was found that spindle speed had significant effect over the wear properties than the load applied. By YSZ coating, wear properties were increased 10 times.

3

Crystallization kinetics of SiO2-MgO-3CaO-P2O5-Al2O3-ZrO2 glass

Yilmaz S., Gunay V.

Materials Science Poland

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2007

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Vol. 25, No. 3

609--617

EN

The crystallization behaviour of SiO2-MgO-3CaO-P2O5-Al2O3-ZrO2 glass was studied using glass samples prepared by melting reagent grade SiO2, MgO, Ca5(PO4)3OH, P2O5, Al2O3 and ZrO2. DTA and XRD analysis revealed the crystallization of whitlockite, anorthite and baddeleyite phases. The crystallization kinetics was studied by applying the DTA measurements carried out at various heating rates. The activation energies of crystallization and viscous flow were measured as 209 kJźmol-1 and 356 kJźmol-1, respectively. The resultant SiO2-MgO-3CaO-P2O5-Al2O3-ZrO2 glass-ceramics revealed very fine and homogenous microstructure.

4

Voltammetric study of aciclovir using controled grow mercury drop electrode

Skrzypek S., Ciesielski W., Yilmaz S.

Chemia Analityczna

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2007

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Vol. 52, No. 6

1071-1078

EN

The electrochemical properties of aciclovir (Acy) were studied by square wave voltammetric method (S\VV) over pH range 1.5-8.0 using a controlled growth mercury drop electrode (CflMDE). In the acid medium the cathodic peak current was observed. Surface catalytic electrode mechanism based on the hydrogen evolution reaction was analyzed. The dependence of the peak current at about -1.3 V vs Ag/AgCI electrode on pH, buffer concentra-tion, nature of the buffer, amplitude, frequency and scan rate was investigated. The best results were obtained in solution of nitric acid at pH 1.9. This electroanalytical procedure enabled to determine aciclovir in the concentration range 2 x 10-7-2 x 10-7 mol L-1. Repeatability, precision and accuracy of the developed method were checked. The detection and quantification limits were found to be 7 x 10-8 and 2 x 10-7 respectively.

PL

Badano elektrochemiczne właściwości acyklowiru (Acy) metodą woltamperometrii z falą prostokątną (SWV) używając elektrody rtęciowej o kontrolowanym wzroście kropli (CGMDE) w zakresie pH l ,5-8. W środowisku kwaśnym zaobserwowano katodowy prąd piku. Analizowano mechanizm elektrodowy związany z katalityczną redukcją wodoru w obecności acyklowiru. Zbadano zależność prądu piku przy potencjale około -1.3 V od rodzaju i stężenia buforu, amplitudy, częstotliwości, szybkości przykładania potencjału. Najlepsze wyniki uzyskano w kwasie azotowym(V) o pH 1.9. Oznaczono acyklowir w zakresie stężeń 2 x 10-7-2 x 10-7 mol L-1. Sprawdzono powtarzalność, precyzję -i dokładność opracowanej metody. Stwierdzono, że granica detekcji wynosi 7 x 10-8, zaś granica ilościowego oznaczenia 2 x 10-7.

5

Finite element analysis of effect of particle alignment on deformation behaviour of metal matrix composite.

Yilmaz S., Aran A.

Inżynieria Materiałowa

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1998

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R. XIX, nr 4

691-694

EN

The goal of this work is to determine the role of the particulate alignment on the overall elastic-plastic behaviour of metal matrix composites. Composite was assumed to be 3D infinite periodic array of particulate embedded in the matrix. Particulate were modeled as spherical. Models with transversely aligned and staggered particle distributions were used. The effect of particle alignment on the overall stress-strain behaviours of the composites are followed through unit cells having different aspect ratios. The difference in the stress-strain behaviour of models shows clearly that the ratio of the particle diameter to the distance between nearest neighbour particles can represent the effect of distribution geometry.