Based on relations for the maximum work at the closed thermodynamic system, the paper presents implementation of a general model for determining the minimum storage volume for compressed air. Due to the mechanical and thermodynamic imbalance of observed model, there are the conditions for obtaining the maximum work. Derived relations, which represe...

By Mitar Perušić, Branko Pejović, Radislav Filipović, Milenko Smiljanić, Mirko Radić

Encapsulation strategy has emerged as a mean to protect sensitive bioactive compounds, toimprove their stability and to deliver their active forms to the targeted place. A number ofbioactives can be encapsulated – cells, enzymes, vitamins, minerals, aromas and flavours, foodcolourants, antioxidants, etc. Over the years various encapsulation t...

By K. Trifkovic, G. Tadić, B. Bugarski

In this study the 3D surface model was successfully applied in investigating the influence of theprocess parameters on the physical and mechanical properties of the glass-ceramics. Glassceramicswas produced from coal fly ash and waste glass through the sintering method. The rawmaterial was taken from “REK Bitola”, a thermal power plant ...

By Biljana Angjusheva, Emilija Fidancevski, Kiril Lisichkov, Vojo Jovanov

New challenges faced by the company at the beginning of the 21st century require new approaches to quality management. Customer perception of the products and service quality is considered one of the key determinants of business performance and for the survival of the organization in a competitive market, and therefore the necessity of continuous m...

By Sonja Ćortoševa, Emilija Gavranska-Nečev

Our recent study on consolidation of marble samples with the purpose of culture heritageprotection occurred by periodical calcium oxalate precipitation on top of quasi parallelepipedicsamples. The overall process consisting of three stages of treatment, starting with 5 % calciumacetate solution for 60 minutes at 20°C, a draining step at 70°...

By Rihana Terzu, Edlira Baraj, Shun Yu, Christiane Förester, Holger Kropf, Kledi Xhaxhiu, Marsilda Come

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