Zorana Golubovic

• PhD
• Senior Research Associate at University of Belgrade

Additive manufacturing (AM), especially vat photopolymerization processes such as digital light processing (DLP), enables the production of highly detailed and complex geometries with precise material structure control. In this study, the influence of internal structure on the mechanical properties of PLA resin specimens produced using a DLP 3D pri...

This study investigates the environmental aging effects on 3D-printed Acrylonitrile Butadiene Styrene (ABS) produced using Fused Deposition Modeling (FDM) and Digital Light Processing (DLP) techniques. The materials in filament (FDM) and resin (DLP) forms were exposed to UV light, humidity, and temperature fluctuations over two months. Mechanical t...

Considering that additive manufacturing technology, has evolved significantly over the past few decades, understanding of materials mechanical properties became important part of researches with the goal of further improvement of production Among the seven different AM technologies, in this research is used digital light processing (DLP) 3D printin...

Additive manufacturing, with its fast development and application of polymeric materials, led to the wide utilization of polylactic acid (PLA) materials. As a biodegradable and biocompatible aliphatic polyester, produced from renewable sources, PLA is widely used in different sectors, from industry to medicine and science. The aim of this research...

In recent years, Additive Manufacturing (AM) has become an increasingly popular method in industrial applications for fabricating components with complex geometries, offering several benefits over traditional (subtractive) manufacturing methods. Among all available AM technologies, “vat photopolymerization” is still a reliable approach for manufact...

The three-point bending test is a valuable method for evaluating the mechanical properties of 3D-printed biomaterials, which can be used in various applications. The use of 3D printing in specimen preparation enables precise control over material composition and microstructure, facilitating the investigation of different printing parameters and adv...

Additive manufacturing (AM), also known as 3D printing, represent technologies where the production of physical models with complex shapes is performed in a layer-by-layer manner, directly from the CAD model. With these processes, there is no need for additional tools or fixtures, and there is no excess material. There are seven different AM techno...

Additive manufacturing and 3D printing technologies are rapidly evolving and influencing changes in design, prototyping, engineering and manufacturing processes in various industries, including aerospace. In order to use 3D printing processes to produce parts with adequate and satisfactory mechanical properties for aircraft that are constantly expo...

The special tool for the internal transport of structural elements of rail vehicles includes two forks (20) with arms (28, 29) that are positioned on the structural element (2) of the rail vehicle being transported, so that the inner arm (28) of each fork is placed in the hollow profile (2a) of the structural element (2) and is being attached from...

Additive manufacturing (AM) technologies have evolved significantly in recent decades, bring- ing new trends to production processes. The advantages compared to conventional technologies are numer- ous: production is simpler and faster, geometry can be adjusted more easily, the quality of finished parts is better, less material is wasted, and costs...

Additive manufacturing technologies have developed rapidly in recent decades, pushing the limits of known manufacturing processes. The need to study the properties of the different materials used for these processes comprehensively and in detail has become a primary goal in order to get the best out of the manufacturing itself. The widely used ther...

Polypropylene (PP) is a relatively new material in fused deposition modeling (FDM) technology. The main feature of this material is its ability to significantly elongate under applied load, unlike any other thermoplastic material used in FDM technology. Not much research has been conducted on this FDM material so far, hence, the subject of this pap...

Selective laser sintering (SLS) is one of the additive manufacturing technologies dedicated to the production of high-quality parts with complex geometries. Here, polyamide 12 (PA12) is a commonly used material, for manufacturing parts with sufficient mechanical and thermal properties. In SLS, many manufacturing parameters have an effect on the mec...

3D printing, also known as additive manufacturing, significantly advances production processes compared to conventional manufacturing. Computer-aided (CAD) modelling provides detailed customization capabilities followed by freedom in manufacturing, resulting in lower production costs and easier repeatability of finished parts. Apart from its numero...

In this paper, we work on the existence of approximate solution for the fixed point equation Rx + Qx = x, when R is a weak contractive mapping and Q is a continuous self-map which is a new topic related to the background literature. Till now, no results were found to find the existence of approximate solution for such a kind of mappings in literatu...

Fused deposition modeling is one of the most widely used 3-D printing technologies, among other additive manufacturing processes, because it is easy to use, can produce parts faster, and the cost of the finished part is low. Printing processes and finished parts are often studied and characterized using different techniques to collect mechanical, n...

Polypropylene (PP) is an extensively studied and tested environment-friendly polymer, whose applications range from product packaging in the food industry to biomedical applications. It is a non-toxic, lightweight material, relatively simple for processing. Research findings show that PP material has higher elongation than any other thermoplastic m...

Three-dimensional printing is an innovative technique which is offering advantages in engineering in terms of modeling and processing, even shapes and geometries which are complex and are difficult to be manufactured with other methods. This novel digital technology provides advantages in production process of an individualized 3D object when compa...

Martial arts and fight sports are mostly based on exchanging the punches and kicks that often result with injuries of face, skull bones, and neck vertebrae. One of possibilities to reduce number of injuries in athletes who deal with martial arts is development of new materials and improvement of designs for helmets used in sport fights. In order to...

The majority of manufacturers of polymer filaments for FDM technology rely their datasheets only on tensile tests, so their documentation usually lacks any data concerning fracture mechanics parameters. Having in mind the importance of fracture mechanics parameters in material design and application e.g., plane-strain fracture toughness, and the fa...

The aim of this paper was to improve the technological procedure, operations and construction of the vibro-motor coupling of the crusher bucket from steel grade C45. The work defines important materials, approaches and methods of welding and plasma cutting. Problems with time-consume and additional finances which are appearing in manufacturing proc...

Most widespread materials in Additive Manufacturing are PLA (PolyLactic Acid) and ABS (Acrylonitrile Butadiene Styrene), which are dissimilar materials in terms of printing abilities and mechanical properties. PLA material originates from renewable resources making it better solution for environment in comparison with petroleum-based ABS material....

Clear dental aligners are used for treating orthodontic anomalies (misaligned teeth, inappropriate contact between upper and lower teeth etc.), minor irregularities and bruxism. Using additive manufacturing technologies clear dental aligners are made of biocompatible photopolymer, using a vat photopolymerization technology. One of problems in appli...

FDM is a commercially widespread 3D printing technology which uses thermoplastic materials for building prototypes and functional parts. Most used materials in this technology are PLA (PolyLactic Acid) and ABS (Acrylonitrile Butadiene Styrene) materials which contain dissimilar mechanical properties and printing abilities. PLA is considered as a go...

Many filtration systems employing perlite granulations have been designed so far. Size distribution of perlite particles directly influences the retention properties of filter media. The information on the size distribution of perlite particles, used in each specific dead-end filtration process (the flow of fluid being filtered is perpendicular to...

The aim of this paper is to present the behaviour of specimens made of polyeth-ylene material PE 80, subjected to tensile load until failure. Measurements of the temperature distribution have been done using the infrared thermography during specimens loading. Finite element analysis was performed in ABAQUS software, where numerical models were made...

The steels operating at elevated temperatures are well known to be exposed to premature failure due to cracking caused by constant thermal stress, i. e. secondary creep process. Therefore, creep crack growth tests were carried out on compact tension specimens machined from P91 weld joint at 600°C to determine its behavior in realistic conditions. A...

In this paper, we introduce the concept of partial cone b-metric spaces as a generalization of partial metric, cone metric and b-metric spaces and establish some topological properties of partial cone b-metric spaces. Moreover, we also prove some common fixed point theorems for cyclic contractive mappings in such spaces. Our results generalize and...

This paper highlights the changes of polyethylene behaviour during various loading rates. The experimental programme was carried out on samples taken from PE80 polyethylene gas pipes with simulated imperfections with bilateral V-notch, U-notch and central hole. The hybrid technique tensile test – infrared test was used for examining the fracture be...

In this paper we obtain some equivalences between cyclic contractions and non-cyclic contractions in the framework of b-metric spaces. Our results improve and complement several recent fixed point results for cyclic contractions in b -metric spaces established by George et al. (2015) and Nashine et al. (2014). Moreover, all the results are with muc...

Contact lenses are a common optical aid to provide help with refractive anomalies of the human eye. Construction of contact lenses is a complex engineering task as it requires knowledge of optics, materials science, production and characterization methods for product quality. Besides correcting refractive anomalies, by using contact lenses it is po...

Contact lenses are a common optical aid to provide help with refractive anomalies of the human eye. Construction of contact lenses is a complex engineering task as it requires knowledge of optics, materials science, production and characterization methods for product quality. Besides correcting refractive anomalies, by using contact lenses it is po...

Structural modifications can cause changes in the matrices of some elements. Depending on the type of structure, or a desired change, a group of elements can be modified. This paper analyzes the effects of small and large-scale modifications of some groups of elements on structural eigenvalues and frequencies. The process of analysis is done using...

We prove the existence of common fixed points for three relatively asymptotically regular mappings defined on an orbitally complete ordered metric space using orbital continuity of one of the involved maps. We furnish a suitable example to demonstrate the validity of the hypotheses of our results.

New coupled coincidence point and coupled fixed point results in ordered partial metric spaces under the contractive conditions of Geraghty, Rakotch, and Branciari types are obtained. Examples show that these results are distinct from the known ones.

Next to the hydrophilic surfaces is found existence of solute-free interfacial zones i.e. exclusion zones. It appears that their properties are different than those in bulk water, and that their width can be up to several hundreds of micrometers. From physiological point of view parallel can be drawn between zone of exclusion and tear film. Both st...

Diatomaceous Earth, also known as diatomite, diatomaceous silica, or kieselguhr is the material of natural origin which is composed of the skeletons of diatoms, single-celled algae, which are accumulated in huge beds. Some diatomite's are industrially processed and used for different applications most frequently as filter aid. Particle size distrib...

When filtering products with a high level of non-soluble solids and containing filtration-inhibiting substances, a variety of different filter aids can be used. Among others, kieselguhr and perlite are possible materials for this purpose. The selection of the granulation that should be applied depends on the filtered liquid medium and the desired r...

In this paper, the concept of set-valued contraction of Nadler type in the setting of tvs-cone spaces was introduced and a fixed point theorem in the setting of tvs-cone spaces with respect to a solid cone was proved. Obtained results extend and generalize the main results of [S.B. Nadler Jr., Multi-valued contraction mappings, Pacific Journal of M...

In this paper we extend and generalize common fixed point theorems for six self-maps of Singh and Jain [B. Singh, S. Jain, A fixed point theorem in Menger space through weak compatibility, J. Math. Anal. Appl. 301 (2005) 439–448] from Menger and metric spaces to cone metric spaces. We also extend the notions of compatible and weakly compatible mapp...

Kieselgur (diatomaceous earth – DE) and perlite are materials of natural origin, commonly used as mediums for mechanical filtration in food and biopharmaceutical industry. The particles size distribution of any filter granulation, composed of these materials, has to be appropriately prepared. In this paper the particle size distributions of two DEs...