Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 3

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Content available remote

Pyrolysis of Low Rank Lignites

100%
Koyun A., Hazar Yoruc A., Ceylan Erdogan D., Ahlatcioglu E.
Acta Physica Polonica A
|
2013
|
vol. 123
|
issue 2
396-397
EN
In this study, six different Turkish coals were studied. One of them was Zonguldak coal and the others were low rank Turkish lignites. The amount of the pyrolysed gases of the coal as CH_4, C_3H_8, CO, CO_2, SO_2 were determined from the experiments by using several first order reaction models that include energy distribution and the activation energy distribution during the pyrolysis was calculated at the same time. The results of pyrolysis experiments of coals were examined by means of several first order reaction models that include energy distribution. The tar amounts and overall conversion of six different coals, activation energies of nine volatile components output, standard variation values that belong to their energy distribution, maximum quantity of product of each component and molecular collision coefficients were determined. As a result of using these variables in the model equations, conversion quantities for all of the compounds of six types of coals and variation of activation distribution functions with respect to the kinds of coals were presented graphically with a comparison of the cited data in references.
2
Content available remote

Effect of Precipitation Method on Properties of Hydroxyapatite Powders

100%
Hazar Yoruç A., Karakaş A., Ayas E., Koyun A.
Acta Physica Polonica A
|
2013
|
vol. 123
|
issue 2
371-373
EN
The aim of this study was the compare the properties of hydroxyapatite as a function of two different methods (chemical and biomimetic precipitation). Powder products were called as chemical hydroxyapatite for chemical method and biomimetic hydroxyapatite for biomimetic method. Precipitated powders with both methods were characterized by Fourier transform infrared, X-ray diffraction, X-ray fluorescence and measurements of hardness and density. Chemical analysis results showed that dried-biomimetic hydroxyapatite sample consists of hydroxyapatite [Ca_{10}PO_4)_6(OH)_2] as main phase and beta-tricalcium phosphate (β-TCP) as secondary phase and dried-chemical hydroxyapatite sample also includes pure hydroxyapatite phase. Chemical hydroxyapatite and biomimetic hydroxyapatite powders were sintered using by spark plasma sintering method. Vickers hardness values of sintered disk samples were measured. Furthermore chemical structure of the final products was analyzed. Also density values of chemical hydroxyapatite and biomimetic hydroxyapatite disks were measured. Finally it is concluded that different precipitation methods affect hydroxyapatite properties and this can be an advantage for biomedical applications.
3
Content available remote

Comparison of Properties of Hydroxyapatite Powders Synthesized by Chemical and Biomimetic Techniques

100%
Hazar Yoruç A., Karakaş A., Koyun A., Yildiz T.
Acta Physica Polonica A
|
2012
|
vol. 121
|
issue 1
233-235
EN
Hydroxyapatite [HA; Ca_{10}(PO_4)_6(OH)_2] which composes inorganic phase of bones and teeth is one of the biomedical materials for artificial bone, reconstruction of broken or disordered bones, coating of metallic biomedical materials and dental surgery with its great biocompatibility. In this study, HA powders were synthesized from aqueous suspensions containing H_3PO_4 and Ca(OH)_2 with 1.67 Ca/P ratios (chemical HA, CHA) and second process is carried out in simulated body fluids consisting of (NH_4)_2HPO_4 and Ca(NO_3)_2 ·4H_2O as biomimetic hydroxyapatite (BHA). Moreover, properties of bovine HA (BoHA) and commercial HA (CoHA) were compared with properties of synthesized HA powders. Chemical structures of synthesized powders have been examined by the Fourier transform infrared technique and X-ray diffraction. The results showed that BHA powders have a pure HA content and no secondary phase, CHA also has monetite phase as secondary phase with HA in its structure. Particle size analysis was carried out with laser particle sizer and zeta-sizer, surface area of powders has been analyzed by the Brunauer-Emmett-Teller technique. Powder morphology is determined using scanning electron microscopy. As a result two different synthesis methods affected properties of HA powders.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.