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Wyświetlanie 1-18 z 18
Tytuł:
Near-Infrared Tunable Reflection and Absorption Using Nanostructured Thin Film Structures Employing Phase-Change Material
Autorzy:
Ozdemir, A.
Kocer, H.
Powiązania:
https://bibliotekanauki.pl/articles/1398701.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Pt
Opis:
We present the design of a polarization-dependent tunable nanostructured thin film absorber in the near-infrared region. Germanium antimonide tellurite (GST) was employed as the phase change material in the designed structure. Our structure is composed of a periodic grating-type array of 150 nm thick Au buried with 50 nm thick GST layer from the top of the Au layer. The period of the gratings is 2 µm and in each period, GST width is 1 µm. GST was selected as the active phase change material because its optical properties undergo a substantial change during a structural transition from amorphous to crystalline phase. The optical absorption and reflection properties of the designed structure with respect to the geometric and material parameters were systematically investigated using the finite difference time domain computations. It was shown that absorption peak or reflection dip at the resonant wavelengths in the near-infrared region was red shifted from 2039 nm to 2143 nm wavelength by switching the phase change material from its amorphous to crystalline states. The distributions of the electric field and absorbed power at the resonant wavelengths with respect to different phases of the GST were investigated to further explain the physical origin of the absorption. Our study provides a path toward the realization of tunable infrared absorbers for applications, such as selective infrared emitters, infrared camouflage, sensors, and photovoltaic devices.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 464-467
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
State-space modeling of an EPW in discrete time and an observer design for state variable estimation
Autorzy:
Özdemir, A.
Erdem, Z.
Usuman, I.
Powiązania:
https://bibliotekanauki.pl/articles/1068329.pdf
Data publikacji:
2016-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.30.Yy
89.20.Kk
02.30.Cj
02.70.-c
07.05.Dz
Opis:
The purpose of this study is to obtain the dynamic model of an electrical powered wheelchair and to estimate the state variables of right and left DC motor currents with the designed observer. First, the dynamic equations are written and then discrete-time state space model of the electrical powered wheelchair is directly obtained from this dynamic equations. Discrete time state space model of the electrical powered wheelchair is verified with the transfer function obtained using the dynamic equations. In addition, the accuracy of the estimated left and right DC motor current values are validated in the simulation results.
Źródło:
Acta Physica Polonica A; 2016, 130, 1; 228-232
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Boriding of binary Ni-Ti and ternary Ni-Ti-Cu shape memory alloys
Autorzy:
Ucar, N.
Turku, N.
Ozdemir, A.
Calik, A.
Powiązania:
https://bibliotekanauki.pl/articles/1065676.pdf
Data publikacji:
2016-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.66.Dk
61.72.-y
62.20.Qp
Opis:
In this work, the boriding of binary (Ni-Ti) and ternary (Ni-Ti-Cu) shape memory alloys was carried out in a solid medium at 1173 K for 8 h using the powder pack method with Ekabor-Ni powders. Characterization of boride layer formed on the surface of alloys was identified by optical microscopy and scanning electron microscopy. TiB₂, NiB₂ and SiC phases in the boride layer of borided binary (Ni-Ti) and ternary (Ni-Ti-Cu) shape memory alloys was confirmed by X-ray diffraction analysis. The microhardness and thickness of the boride layers were measured. The obtained hardness values show a hardness anomaly due to porosity and structural defects with increase of Cu content, while a decrease in the value of hardness moving from the boride layer to main structure was observed.
Źródło:
Acta Physica Polonica A; 2016, 130, 1; 492-495
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Frequency and voltage-dependent dielectric properties and AC electrical conductivity of (Au/Ti)/Al₂O₃/n-GaAs with thin Al₂O₃ interfacial layer at room temperature
Autorzy:
Güçlü, Ç.
Özdemır, A.
Kökce, A.
Altindal, Ş.
Powiązania:
https://bibliotekanauki.pl/articles/1065319.pdf
Data publikacji:
2016-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.30.+y
Opis:
An (Au/Ti)/Al₂O₃/n-GaAs structure with thin (30 Å) interfacial oxide layer (Al₂O₃), formed by atomic layer deposition technique is fabricated to investigate both frequency and applied bias voltage dependences of real and imaginary parts of dielectric constant (ε' and ε'') and electric modulus (M' and M''), loss tangent tanδ and ac electrical conductivity σ_{AC} in a wide frequency range from 1000 Hz to 1 MHz at room temperature. The dielectric properties of the (Au/Ti)/Al₂O₃/n-GaAs metal-insulator-semiconductor structure are obtained using the forward and reverse bias capacitance-voltage (C-V) and conductance-voltage (G/ω-V) measurements in the applied bias voltage range from -4 V to +4 V, at room temperature. Experimental results show that the dielectric parameters were strongly frequency and voltage dependent. For each frequency the (C-V) plots show a peak and the change in frequency has effect on both the intensity and position of the peak. ε', ε'' and tanδ decrease with increasing frequency, whereas σ_{AC} increases with increasing frequency at applied bias voltage. M' increases with the increasing frequency and reaches a maximum. M'' shows a peak and peak position shifts to higher frequency with increasing applied voltage. It can be concluded that the ε', ε'', tanδ, M', M'' and σ_{AC} values of the (Au/Ti)/Al₂O₃/ n-GaAs structure are strongly dependent on both the frequency and applied bias voltage especially in the depletion and accumulation region. Also, the results can be deduced to imply that the interfacial polarization is easier at low frequencies, therefore contributing to the deviation of dielectric properties and AC electrical conductivity of (Au/Ti)/Al₂O₃/n-GaAs structure.
Źródło:
Acta Physica Polonica A; 2016, 130, 1; 325-330
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Role of Hydrostatic Pressure in Electrical Properties of Au/n-GaAs Schottky diodes with Substituted Polyaniline Interfacial Layer
Autorzy:
Özdemir, A.
Abdolahpour Salari, M.
Kökce, A.
Uçar, N.
Powiązania:
https://bibliotekanauki.pl/articles/1031654.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Kp
73.20.At
74.62.Fj
Opis:
Au/polymer P2ClAn(H₃BO₃)/n-GaAs Schottky barrier diodes, where P2ClAn stands for poly(2-chloroaniline), have been fabricated. To fabricate Schottky diodes with polymer interface, n-type GaAs wafer was used. The P2ClAn polymer solution was applied on the front face of the n-GaAs wafer by a pipette. The P2ClAn emeraldine salt was chemically synthesized by using boric acid (H₃BO₃). Schottky diode parameters, such as ideality factor, barrier height and series resistance have been measured, as functions of hydrostatic pressure, using the current-voltage technique. The ideality factor values of Au/P2ClAn/n-GaAs Schottky barrier diodes have decreased from 3.38 to 3.01, the barrier height has increased from 0.653 to 0.731 eV at 0.36 kbar and series resistances were ranging from 14.95 to 14.69. The results obtained from I-V characteristics of Au/P2ClAn/n-GaAs Schottky barrier diodes show that pressure treatment improves the rectifying properties of the diodes. These diodes can be used as pressure-sensitive capacitors, due to pressure-dependence of diode parameters.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 1118-1121
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biometrical and biochemical properties of fruits of mini cucumber plants grown under various irrigation regimes in an unheated greenhouse
Autorzy:
Çebi, U.K.
Çakir, R.
Altintas, S.
Ozdemir, A.G.
Powiązania:
https://bibliotekanauki.pl/articles/12193499.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Opis:
The study aimed to determine the most appropriate irrigation scheduling for mini-type cucumber plants grown as a spring-summer cycle crop. The research was conducted in a greenhouse structure in the fields of the Research Institute in Kirklareli. Marathon cucumber plants were used as the plant material in the trials. The split plot design experimental layout in 3 replications was used in the research. Four different plant–pan coefficients (0.75, 1.00, 1.25 and 1.50) and two irrigation intervals (2 and 4 days) were applied as subplots and main plots of the study, respectively. As a result of the 3-year investigation, it was determined that yields, number of cucumber fruits, and fresh cucumber fruit weight, length and diameter increased with the increase in the irrigation water amount. The highest average total soluble solids (Brix) value of 5.0 was recorded under conditions of most severe stress imposed on the plots with lowest water application rates of Kcp 0.75. While the lowest values of 4.0–4.1 were obtained for plants growing under more favorable moisture conditions in plots with application of Kcp 1.25 and 1.50. Statistically significant positive linear relationships were obtained for irrigation water amount on one hand, and fruit number, fruit mean weight, fruit length and diameter on the other, while the relationship between water applied and TSS (Brix) was negative.
Źródło:
Acta Scientiarum Polonorum. Hortorum Cultus; 2018, 17, 5; 199-212
1644-0692
Pojawia się w:
Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diffusion Kinetics of Binary Ti-Ni Shape Memory Alloys
Autorzy:
Ucar, N.
Dogan, S.
Ozdemir, A.
Karakas, S.
Calik, A.
Powiązania:
https://bibliotekanauki.pl/articles/1031122.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
boriding
shape memory alloys
microhardness
boride layer
diffusion
Opis:
In this work, the boriding of binary Ti-Ni shape memory alloys was carried out in a solid medium at 1173 and 1273 K for 2, 4, and 8 h using the powder pack method with Ekabor-Ni powders. The boride layer was characterized by optical microscopy and scanning electron microscopy. The obtained results show that boride layer thickness increases with the increasing boriding temperature and time. Depending on temperature and boride layer thickness, the diffusion process is thermally activated, with the mean value of the activation energy being close to 67 kJ/mol.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 524-526
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Frequency C-V and G-V Characteristics of Au/Poly (3-Substituted thiophene) (P3DMTFT)/n-GaAs Schottky Barrier Diodes
Autorzy:
Özdemir, A.
Akcan, D.
Lapa, H.
Yavuz, A.
Duman, S.
Powiązania:
https://bibliotekanauki.pl/articles/1402507.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.30.+y
Opis:
The frequency-dependent electrical characteristics of Au/Poly (3-Substituted thiophene) (P3DMTFT)/ n-GaAs Schottky barrier diodes have been investigated by using capacitance-voltage (C-V) and conductance-voltage (G/ω-V) measurements at room temperature. Negative capacitance behavior has been observed in the C-V characteristic for each frequency. The magnitude of absolute value of C was found to increase with decreasing frequency in the forward bias region. The value of G/ω increases with decreasing frequency in the positive region. This can be attributed to the increase in the polarization at low frequencies and to the fact that more carriers are introduced into the structures. Negative capacitance phenomenon can be explained by the loss of interface charges from the occupied states below the Fermi level, caused by impact ionization process. According to obtained result, the values of C and G/ω are strong functions of frequency and applied bias voltage, particularly in the accumulation an inversion region. Doping concentration $(N_{d})$, diffusion potential $(V_{d})$, Fermi energy level $(E_{f})$, and barrier height $(Φ_{b}(C-V))$ values have been calculated from reverse bias $C^{-2}-V$ plots for 3 MHz. Finally, the obtained value of $R_{s}$ in the accumulation region increases with decreasing frequency.
Źródło:
Acta Physica Polonica A; 2015, 128, 2B; B-450-B-454
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simultaneous decolorization of ternary dye mixture from aqueous solution by electrocoagulation
Autorzy:
Keskin, C. S.
Özdemir, A.
Karabayir, E.
Şengil, I. A.
Powiązania:
https://bibliotekanauki.pl/articles/208189.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
coagulation
mixtures
COD removal
dye concentration
electrocoagulation
NaCl concentration
ternary mixtures
decolorization
koagulacja
mieszaniny
usuwanie COD
stężenie barwnika
elektrokoagulacja
stężenie NaCl
mieszanina trójskładnikowa
odbarwianie
Opis:
The current study focused on the treatment of a ternary mixture of dyes which includes Disperse Blue 56 (DB56), Basic Yellow 28 (BY28) and Acid Violet 90 (AV90) using the electrocoagulation (EC) process with iron electrodes. In the presence of all dye molecules, the optimum pH was found to be 6, optimum NaCl concentration was 3000 mg/dm3 and optimum current density was 8.66 mA/cm2. Under the optimized conditions in the case of 100 mg/dm 3 each dye concentration, the average colour removal efficiency was reached 93%. Dye concentration dependent highest COD removal efficiency was measured as 88.70% at 150 mg/dm3 dye concentration.
Źródło:
Environment Protection Engineering; 2013, 39, 3; 119-133
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study of the Properties of Paper Sized with Styrene-Butyl Acrylate Copolymers
Autorzy:
Özdemir, M.
Özdemir Alp, M.
Aytaç, A.
Deniz, V.
Powiązania:
https://bibliotekanauki.pl/articles/1031427.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.35.bm
68.47.Mn
81.05.Qk
Opis:
In this study, styrene 70 wt.%-butyl acrylate 30 wt.% copolymer-based surface-sizing materials were synthesized using semi-batch emulsion polymerization and applied on the paper. Four different emulsifiers, with different ethylene oxide numbers, at ratios of 10%, 7% and (2, 2'-azobis (2-methylpropionamidine) dihydrochloride (A)) as initiator were used for emulsion polymerization. Eight different copolymers were synthesized. Synthesized copolymers were used as surface sizing agents for the paper surface. Ion exchange capacity, pH, Fourier transform infrared spectroscopy, differential scanning calorimetry and thermal gravimetric analysis were used for the characterization of the copolymer properties. Contact angle measurements, Cobb test, and scanning electron microscopy analysis were carried out to determine the surface properties of the paper samples. Presence of copolymer formations was proven with the Fourier transform infrared analysis. Contact angle measurements of the copolymer sized paper surface have shown hydrophobic behaviour in samples, with the exception of E-3/7/A sample. The lowest Cobb value was observed for E-2/7/A sample. The highest thermal stability was also observed for E-2/7/A sample. The scanning electron micrographs show that the paper loses its fibrous structure and it is seen that the copolymer adheres to the fibrous tissue.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 1098-1101
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation into the surface properties of papers sized with styrene-acrylate-cationic monomer based terpolymers
Autorzy:
Özdemir, M.
Aytaç, A.
Deniz, V.
Powiązania:
https://bibliotekanauki.pl/articles/1050997.pdf
Data publikacji:
2017-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.47.Pe
82.35.-x
Opis:
In this study, styrene(St)/2-ethyl hexyl acrylate(2-EHA) based surface sizing materials were developed with four different cationic monomers (CM), namely diallyldimethyl ammonium chloride (DADMAC), [2-(methacryloyloxy) ethyl] trimethylammonium chloride (MATMAC), [3-(methacryloylamino) propyl]-trimethyl ammonium chloride (MAPTAC), (viniylbenzyl) trimethyl-ammonium chloride (VBTMAC). Ternary polymerization was realized with emulsion polymerization, by using 2,2'-azobis (2-methylpropionamidine) dihydrochloride (A) as initiator. Thermal properties of the synthesized terpolymers were determined with differential scanning calorimeter and thermal gravimetric analysis. Differential scanning calorimeter results showed that glass transition temperature (T_{g}) values of polymers were not dependent on the types of cationic monomers, and were found about 44-45°C. Ion exchange capacities of the terpolymers were determined. The latexes produced were used as sizing materials for paper surface treatment. Then critical surface properties of the papers sized such as water resistance (Cobb value) and contact angle were measured. It was found that the best, i.e. the lowest Cobb results were obtained when MATMAC and MAPTAC cationic monomers were used in terpolymers.
Źródło:
Acta Physica Polonica A; 2017, 131, 1; 178-181
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of $Na_2O//K_2O$ Ratio on the Deformation Behaviour of the Floor Tile Bodies
Autorzy:
Tamsu, N.
Vedat Bayrak, A.
Ozdemir, H.
Powiązania:
https://bibliotekanauki.pl/articles/1399791.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Mh
Opis:
Floor tile bodies have excellent technical characteristics particularly as regards mechanical properties and frost resistance. Besides of these properties they could not have any deformation during firing. Considering floor tiles are generally fired in roller kilns, tiles are moving along the kiln carried by the rollers. It is possible that tiles can be bended by the roller movement because it is submitted to vertical forces due to its own weight. Pyroplastic deformation is the bending of a ceramic specimen caused by gravity during heat treatment. It can be defined as deformation or the loss of a shape of a product during its firing. Deformation behaviour of the tiles is related to liquid phases formed during firing or to a reduced viscosity of these phases. In this study, effects of altering $SiO_2//Al_2O_3$ ratio and $Na_2O//K_2O$ ratio of the tile composition on the deformation behaviour of the floor tiles. Correlations between compositional change and deformation behaviour of the tile bodies will be also discussed in this presentation.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 283-284
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Calcined Colemanite Addition on the Rheological Behaviour of Porcelain Suspension
Autorzy:
Özdemir, Y.
Akpınar, S.
Abbak, S.
Evcin, A.
Powiązania:
https://bibliotekanauki.pl/articles/1031614.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
rheology
colemanite
slip casting
Opis:
A standard composition for hard porcelain production was prepared by mixing 50 wt% kaolin, 25 wt% potassium feldspar and 25 wt% quartz. Calcined colemanite powders were added to the porcelain formulation by replacing the potassium feldspar up to 5 wt% to explore its effect on the rheological behaviour of porcelain slip casting. A rheological study has been carried out in order to optimize the processing of the slip casting by using a rotational stress-controlled rheometer. The measurements were performed at constant temperature (25°C) using a parallel plate configuration. Sweep measurements were then conducted in the shear rates ranging from about 0.1-1000 s¯¹. The stability of the suspensions with ammonium polyacrylate (Darvan 821A) was determined in order to select the suitable dispersant amount. In order to achieve casting of acceptable characteristics on a plaster of Paris mould, the slurry should have the appropriate thixotropic or shear-thinning behaviours. Therefore, the same favourable thixotropic behaviour of slurries of different amount of calcined colemanite powders, the solid contents of the slurries have been optimised.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 825-829
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of dietary L-arginine intake on the level of antibody titer, the relative organ weight and colon motility in broilers
Autorzy:
Bulbul, T.
Ozdemir, V.
Bulbul, A.
Ulutas, E.
Powiązania:
https://bibliotekanauki.pl/articles/30881.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
This study was carried out to determine the effect of L-arginine (L-Arg) levels in diet at the starter, grower and finisher phases on immune response, organ development, nitric oxide (NO) metabolism and colon motility in broilers. A total of 500 one-day-old Ross-308 broiler chickens of mixed sex were separated into one Arg-deficient group and four experimental groups. Each group was then divided into five subgroups of 20 birds each. Arginine deficient group for all phases was fed a basal diet which contained 10% less L-Arg than optimum Arg requirement recommended by the breeder. Experimental groups were fed a basal diet supplemented with L-Arg which was progressively 10% increased in groups. Thus, the diet contained 90, 100, 110, 120 and 130% of optimum Arg requirement for each phases in groups, respectively. The highest serum infectious bursal disease antibody titer (IBD) was observed in the experimental group which was fed the diet containing 110% L-Arg at grower phase (P<0.05), whereas Newcastle disease antibody titer did not differ between groups. The relative weight of spleen increased in groups which were fed the diet containing 120 and 130% L-Arg at starter phase as compared to Arg-deficient group (P<0.05). The group which was fed the diet containing 110% L-Arg showed highest relative weight of bursa Fabricii at grower (P<0.05) and finisher (P<0.01) phases. It was observed that serum nitric oxide (NO) concentration decreased in Arg-deficient group (P<0.05). The amplitude of spontaneous colon contractility did not differ between groups at the end of all three phases. However, the frequency of spontaneous colon contractility in the Arg deficient group was higher at starter (P<0.05), grower (P<0.01) and finisher (P<0.05) phases.These results suggest that the supplementation of L-Arg at higher level than optimum Arg requirement in broiler diet has minimal effect on parameters investigated in the study. However, L-Arg-deficiency may negatively affect immune response and the motility of gastrointestinal system due to disruption of NO metabolism at three phases.
Źródło:
Polish Journal of Veterinary Sciences; 2014, 17, 1
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Difference in flotation behavior of galena by single and multi-step chronoamperometric oxidation
Autorzy:
Ozdemir, Orhan
Hampton, Marc A
Nguyen, Tuan
Nguyen, Anh
Powiązania:
https://bibliotekanauki.pl/articles/110510.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
surface roughness
hydrophobicity
contact angle
elemental sulfur
galena
chronoamperometry
Opis:
The relationship between electrochemical oxidation (Chronoamperometry) of galena surfaces and collocterless galena flotation was investigated in detail. The chronoamperometry (CA) micro- flotation experiments and zeta potential experiments were performed with ground galena particles (106×53 μm). In addition, contact angle measurements were carried out with a freshly cleaved galena sample at pH 4 in order to investigate any changes in galena surface hydrophobicity after the surface oxidation electrochemically. The results from this study indicated that there is a strong link between the nano/micro-physico-chemical properties of a sulphide on galena surfaces and collectorless flotation of galena particles at pH 4. The results were also supported with the electrokinetics behavior and contact angle values of galena particles.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 3; 812-821
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and comparative strength analysis of wheel rims of a lightweight electric vehicle using Al6063 T6 and Al5083 aluminium alloys
Autorzy:
Korkut, T. B.
Armakan, E.
Ozaydin, O.
Ozdemir, K.
Goren, A.
Powiązania:
https://bibliotekanauki.pl/articles/368354.pdf
Data publikacji:
2020
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
aluminium alloy wheel
electric vehicle
stress analysis
energy consumption
stopy aluminium
pojazd elektryczny
analiza naprężeń
zużycie energii
Opis:
Purpose: Use of aluminium alloys in critical parts of a vehicle is common since they can combine the two important properties of a material those are being strength and lightweight. The aim in this research is to guide to design process of a wheel with taking example of an electric race vehicle implementation. Design/methodology/approach: In this study, the fatigue strengths of wheels produced for a two-person racing electric vehicle (Demobil09) are evaluated by calculating maximum distortion energy criterion (Von Mises) with Finite Element Analysis. Findings: Aluminium alloy wheels are crucial safety related components and are subjected to static and dynamic loads directly. Using FEA results, the weight and equivalent stress of the wheel are both reduced. So, the energy consumption is also decreased. Modal frequencies of the wheel models are determined. Research limitations/implications: In this paper, the materials analysed are AL6063 T6 and Al5083 aluminium alloys. Different materials can be analysed in future works. Practical implications: This paper is focusing on how to reduce the energy consumption of a two-person electric vehicle concentrating on reducing the weight of vehicle wheels. The vehicle is more technological than mass production cars since it is an electric race car which uses a hub motor, the body and chassis are produced using carbon polymer composites and all electronic units are designed and produced. Although its specialities it has homologated safety equipment like seats and safety belts. Originality/value: All boundary conditions must be analysed in details and a strength analysis must be conducted during design of the wheels for different load cases to ensure the strength of a wheel while keeping the weight as low as possible. In this complex process, this paper can give some clues to designers for strengths and weights of the designs since three different wheel forms are evaluated for reducing energy consumption of the vehicle.
Źródło:
Journal of Achievements in Materials and Manufacturing Engineering; 2020, 99, 2; 57-63
1734-8412
Pojawia się w:
Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bubbling properties of frothers and collectors mix system
Autorzy:
Batjargal, Khandjamts
Guven, Onur
Ozdemir, Orhan
Karakashev, Stoyan I.
Grozev, Nikolay A.
Boylu, Feridun
Çelik, Mehmet Sabri
Powiązania:
https://bibliotekanauki.pl/articles/2146880.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
critical coalescence concentration (CCC)
Sauter diameter (d32)
bubble size distribution (BSD)
Opis:
This paper studies the effect of the type and concentration of selected frothers and collectors mix system on the bubble sizes (Sauter mean diameter, SMD) of bubbling flow produced in a micro flotation cell and the determination of bubble size distribution (BSD). The usage of dodecyl amine hydrochloride (DAH) collector on the critical coalescence concentration of commercial frothers PPG200, PPG400, and PPG600 was investigated in detail. The results of these studies showed that the usage of DAH decreased the CCC of these frothers. Each frother + collector mixing system exhibited its unique ability in preventing coalescence of the bubbles in the order of PPG200 < PPG400 < PPG600. The factorial experiments established that the type of the frother, collector, and their concentration had a major effect on the size of the bubbles. The BSD in the presence of PPG600 + DAH mix system resulted in a little bit wider BSD which indicated the effect of frother type in mixed systems.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 5; art. no. 152890
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical restrictions of the flotation of fine particles and ways to overcome them
Autorzy:
Karakashev, Stoyan I.
Grozev, Nikolay A
Ozdemir, Orhan
Guven, Onur
Ata, Seher
Bournival, Ghislain
Batjargal, Khandjamts
Boylu, Feridun
Hristova, Svetlana
Çelik, Mehmet Sabri
Powiązania:
https://bibliotekanauki.pl/articles/2146879.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fine particle flotation
frequency of collisions
surface force manipulation
thin wetting films
Opis:
This work analyses the basic problems of the fine particles flotation and suggests new ways to overcome them. It is well accepted that the poor recovery of fine particles is due to the small collision rate between them and the bubbles due to the significant difference between their sizes. This common opinion is based on a theory, assuming in its first version a laminar regime, but later has been advanced to intermediate turbulence. It accepts that the particles are driven by the streamlines near the bubbles. In reality, the high turbulence in the flotation cells causes myriads of eddies with different sizes and speeds of the rotation driving both bubbles and particles. Yet, a theory accounting for high turbulence exists and states that the collision rate could be much higher. Therefore, we assumed that the problem consists of the low attachment efficiency of the fine particles. Basically, two problems could exist (i) to form a three-phase contact line (TPCL) the fine particle should achieve a certain minimal penetration into the bubble, requiring sufficient push force; (ii) a thin wetting film between the bubble and the particle forms, thus increasing the hydrodynamic resistance between them and making the induction time larger than the collision time. We assumed particles with contact angle θ = 80°, and established a lower size flotation limit of the particles depending mostly on the size of the bubbles, with which they collide. It spans in the range of Rp = 0.16 um to Rp = 0.40 um corresponding to bubbles size range of Rb = 50 um to Rb = 1000 um. Hence, thermodynamically the particle size fraction in the range of Rp = 0.2 um to Rp = 2 um are permitted to float but with small flotation rate due to the small difference between the total push force and maximal resistance force for formation of TPCL. The larger particles approach slowly the bubbles, thus exceeding the collision time. Therefore, most possibly the cavitation of the dissolved gas is the reason for their attachment to the bubbles. To help fine particles float better, the electrostatic attraction between bubbles and particles occurred and achieved about 92% recovery of fine silica particles for about 100 sec. The procedure increased moderately their hydrophobicity from θ ≈ 27.4° to θ ≈ 54.5°. Electrostatic attraction between bubbles and particles with practically no increase of the hydrophobicity of the silica particles ended in 47% recovery. All this is an indication of the high collision rate of the fine particles with the bubbles. Consequently, both, an increase in the hydrophobicity and the electrostatic attraction between particles and bubbles are key for good fine particle flotation. In addition, it was shown experimentally that the capillary pressure during collision affected significantly the attachment efficiency of the particles to the bubbles.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 5; art. no. 153944
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-18 z 18

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