Two different studies of the thermal aging of polyesters based on lactic and glycolic acidswere compared. Thermal degradation of poly(L-lactic acid) (PLLA), poly(L-lactic acid-co-glycolicacid) (PLLGA) and poly(DL-lactic acid-co-glycolic acid) (PDLGA) was studied by the dielectricthermal analysis (DETA). The aging was performed at 37C in vacuum ove...

By Aleksandra Porjazoska Kujundziski, Dragica Chamovska

The investigated material is a corrosion-resistant, Cu precipitation hardened steel 17-4PH,which undergoes a macroscopic contraction, as a result of applying the following heat treatment:double solution treatment at 1028°C for 1 h (condition A), ageing at 540°C for 4 h (conditionH1025). The second solution treatment at 1028°C was found ...

By R. Sowa, E. Roga, S. Arabasz, A. Dziedzic, I. Dul, A. Kowal, M. Parlinska-Wojtan

Powders based on oxides and oxyhydroxides of aluminum, depending on their characteristics, have very diverse applications in various areas of the chemical industry. In recent years, obtaining powders with nano scale particle size, significantly expanding the possibilities for the application of this type of materials, especially in the field of so-...

By Zoran Obrenović, Miladin Gligorić, Aleksandar Došić, Vladimir Damjanović

Prrenjas clay mineral is found in southeast Albania and has a high content on bentonite. Theinfluence of the sulphuric acid activation on the composition, structure and surface properties ofPrrenjas clay mineral is investigated in this study by means of elemental chemical analysis, X-RayDiffractometry, IR Spectroscopy and gas adsorption-desorption ...

By Altin Mele, Krenaida Taraj, Arjan Korpa

The reduction of the greenhouse gas emissions and the assessment of renewable energy sources are among today’s most challenging tasks. In this context biofuels have emerged as promising alternatives. Successful commercialization and market acceptance of biofuels are dependent on the presence of ions that induce negative impact on the vehicle ...

By Ljubiša Ignjatović, Ivana Sredović Ignjatović

In this study, design of lab scale device for determination of separation properties ofmembranes is presented and analyzed. Device operates with different gas pressure betweenchambers, whereby gas streams perpendicular to the membrane. Using appropriate acquisitionsystem and applying mathematical formulas, mechanism for gas transfer through the mem...

By Aleksandar Grujić, Mirko Stijepović, Jasna Stajić Trošić, Jovana Ilić, Dragutin Nedeljković

Fly ash is useful for a variety of applications, because it is a plaster or silicate or aluminosilicate material which is in an isolated form and in the presence of water is combined with calcium hydroxide (from lime, portland cement or dust from furnaces) and formed mixtures with the characteristics of the binder. In this project analyzed the poss...

By Goran Tadić, Miladin Gligorić, Aleksandar Došić, Radenko Grujić

Biphenylsarean important class of organic compounds. Theyare importantin the field of natural products, polymersand the contemporary medical materials. Synthetic route cross-coupling (Suzukis) reaction, starting from benzenevia the iodoniumsaltto 4-nitro-4'-metilbiphenyl is chosen in this study. The resulting intermediates and final product of the ...

By Ljubica Vasiljević, Ivan Ćirić, Dragana Grujić

The aim of this paper was to develop and optimize the carvedilol tablets formulation using the full factorial design. The content of binder (PVP K30), content of disintegrant (crospovidone) and main compression force were used as the independent variables. Tablets were prepared by wet granulation. The percentage of released carvedilol from prepared...

By Predrag Sibinovic, Valentina Marinkovic, Radoslav Palic, Ivan Savic, Ivana Savic -Gajic, Dragan Milenovic, Rada Jankovic

This paper studies the effect of process parameters on the sorption characteristics of zeolite 4A. The observed process are related to the influence of crystallization temperature, crystallization time and influence concentrations of Na2O. In parallel with the examination of the impact of these parameters on the capacity of water sorption of zeolit...

By Mladen Janković, Anđelko Tanasijević, Radislav Filipović, Mitar Perušić