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Preliminary Mission Specifications of MOSAIC Satellite
No full textNano satellites, also known as nano-sats, are small satellites that typically weigh less than 10 kg. Here, we present CubeSat, a class of nano-sats, that consists of one or more “cubes” that form the satellite structure where platform and payload equipment is to be placed. This paper discusses preliminary mission specifications as a first step of designing MOSAIC (Multi-purpOSe AcademIc Cubesat). MOSAIC is to be the first Serbian scientific CubeSat satellite with ambitious technological, scientific and educational goals. The specifications include satellite power, mass and link budgets, and the technical documentation for the mission payload
Experimental and numerical analysis of the fatigue fracture behavior of the Ti-6Al-4V alloy
No full textThis paper presents the results of an experimental and numerical
analysis of the fatigue fracture behavior of the selected Ti-6Al-4V
alloy, which was chosen because of its frequent use in industrial
applications.under Contract 451-03-136/2025-03/20021
A TECHNICAL SOLUTION FOR THE AUTOMATIC APPLICATION OF LIQUID STARTER FERTILIZER DURING MAIZE SOWING
No full textGlobal research has consistently demonstrated that the proper use of
fertilizers in maize production technology can substantially increase grain yield. Among
recent advancements in sowing techniques is the integration of operations that allow
the simultaneous application of specialized mineral fertilizers, particularly liquid starter
fertilizers. This paper introduces a novel conceptual design of the EUKU-01 technical
system, which, when implemented on a standard pneumatic seeder, enables the automated
delivery of liquid starter fertilizer in parallel with maize sowing. The system employs
an innovative approach that facilitates the application of fertilizer in predefined modes
(point or band placement) and adjustable quantities (1–250 l ha-1), either directly onto
the seed or in its immediate proximity. Activation is achieved through photoelectric
sensors that detect seed passage, generating a signal transmitted to the electronic control
unit (ECU). The ECU subsequently regulates the operation of nozzles mounted on
additional furrow openers. Detailed technical specifications of the system’s components,
the ECU schematic, and the overall operational principle are presented. The EUKU-01
system demonstrates the potential to enhance maize production through the innovative
integration of electronic and mechanical components, offering a significant contribution
to reducing production costs and improving yield outcomes.
The abstract should summarize the contents of the paper in short terms, up to
500 words.contract registration number: 451-03-137/2025-03/20010
FROM MODULAR LEGACY TO OPEN INNOVATION: EVOLUTION OF THE LOLA CNC SYSTEM ARCHITECTURE
No full textThis paper provides a comprehensive overview of the development, technical architecture, and
practical applications of the LOLA 30 CNC system, a landmark achievement in domestic industrial innovation in the field of numerical control. Developed in the early 1980s by the LOLA Institute, the system is examined within its historical context, with particular attention to its architectural features and its broader impact on industrial autonomy and engineering education. Special emphasis is placed on its modular design, integration with the PA512 programmable logic controller, and representative use cases. The paper also presents a comparative analysis between the LOLA 30 CNC and the modern LOLA ROSA CNC system, which is based on open-architecture hardware and software. Key technological advancements of the new system, particularly in terms of reconfigurability and distributability, are highlighted.Conference proceedings [Elektronski izvor] : 60th Anniversary of the Association of Production Engineering of Serbia
/ 40th International Conference of Production Engineering ICPES 2025 - Serbia 2025, Nis, Serbia, 18th - 19th
CIP - Каталогизација у публикацији
Народна библиотека Србије, Београд
621.7/.9(082)(0.034.2)
621.7/.9:669(082)(0.034.2)
681.5(082)(0.034.2)
005.6(082)(0.034.2)
004.896(082)(0.034.2
INFLUENCE OF LAYER HEIGHT ON CAVITATION RATE OF 3D-PRINTED PLA
No full textThis study investigates the cavitation erosion behaviour of PLA (polylactic acid) specimens fabricated by Fused Deposition Modelling (FDM) using different layer heights (0.1, 0.2, and 0.3 mm). The samples were exposed to cavitation at a frequency of 20 ± 0.5 kHz for 60 and 120 minutes. Visual inspection revealed that smaller layer heights resulted in finer surface morphology, better interlayer bonding, and improved resistance to cavitation. After 60 minutes, slight surface roughening and local delamination were observed in all samples, while after 120 minutes, surface degradation became more pronounced, especially for larger layer heights. Samples printed with a 0.1 mm layer height mainly exhibited plastic deformation and minor delamination, those with 0.2 mm showed a combination of plastic deformation and delamination, whereas the 0.3 mm specimens were dominated by large-scale detachment and severe surface damage. The cavitation rate diagram, obtained from mass loss measurements, confirmed these observations. The lowest mass loss rate (0.77 mg/min) was recorded for the 0.1 mm samples, while the highest rate (1.50 mg/min) corresponded to the 0.3 mm samples. The results demonstrate that increasing layer height significantly reduces the cavitation resistance of FDM-printed PLA due to weaker interlayer cohesion and higher surface roughness.451-03-137/2025-03/200105, 451-03-136/2025-03/200135, 451-03-136/2025-03/20028
Proceedings of the 1st Biennial ESIS-CSIC Conference on Structural Integrity - BECCSI 2025
No full textDear Colleagues, Dear Friends,
It is with great pleasure that we welcome you to our beautiful city of Belgrade (Serbia) for the 1st edition of the Biennial ESIS-CSIC Conference on Structural Integrity (BECCSI 2025). But first, a couple of words about the organisers of this international scientific event - the European Structural Integrity Society, the China Structural Integrity Consortium and the co-organiser, the Society for Structural Integrity and Life “Prof dr Stojan Sedmak”.
The China Structural Integrity Consortium (CSIC) is a non-profit academic organization committed to promoting academic exchanges, advancing scientific research, facilitating engineering applications, and disseminating knowledge specifically in the realm of structural integrity. Its origins can be traced back to 2002, spearheaded by a consortium of universities and research institutes that have historically participated in joint research focused on structural integrity, especially concerning the safety technology of pressure vessels and pipelines. In 2003, the inaugural International Fracture Mechanics (FM) Symposium took place in Shanghai. As the discipline and its application areas broadened, the FM series of conferences transitioned in 2010 to the International Symposium on Structural Integrity (ISSI), with member institutions rotating the responsibility of organization. In November 2012, following extensive discussions and consultations among the Materials Division, Pressure Vessel Division, and Failure Analysis Division of the Chinese Society of Mechanical Engineering, the decision was made to collaboratively establish the CSIC. The latest ISSI took place in Dongguan from November 5th to 8th, 2024.
The European Society for Structural Integrity (ESIS) is an esteemed international non-profit engineering scientific society. Its primary mission is to foster and enhance knowledge surrounding all facets of structural integrity and to disseminate that knowledge widely. The overarching goal is to elevate the safety and performance of structures and their components. The origins of the European Structural Integrity Society can be traced back to November 1978 during a summer school event in Darmstadt, Germany. Initially, it was known as the European Group on Fracture. From 1979 to 1988, several technical committees were established, with the Elasto-Plastic Fracture Mechanics committee being the first among them. The initial vision was to emulate the work of the ASTM committee in Europe. Dr. L.H. Larsson from the European Commission Joint Research Centre served as the inaugural president of the European Structural Integrity Society. Currently, ESIS comprises a total of 24 technical committees and national groups across all European countries. The present president of ESIS is Prof. Aleksandar Sedmak from the University of Belgrade in Serbia.
The Society for Structural Integrity and Life (Serbian Društvo za integritet i vek konstrukcija "Prof. Dr. Stojan Sedmak", or simply DIVK) is a non-governmental, non-profit society of experts engaged in the practical application of the theory of fracture mechanics. Founded in 2001, today the Society has more than 240 registered members and engages in a number of activities such as seminars, publications, cooperation with other societies, and more. The journal "Structural Integrity and Life" is published by DIVK. The Society aims to master contemporary theoretical, numerical, and experimental methods for structural integrity assessment in order to apply them to ensure in-service safety and reliability and to extend their design life, enable the prevention of failures to minimize the risk of endangering human lives and polluting the environment, and improve the level of education and publishing in the field
INFLUENCE OF PRINTING ORIENTATION ON THE ELASTIC MODULUS OF PA12 SPECIMENS OBTAINED BY SLS TECHNOLOGY
No full textThis paper describes a study that examined the effect of printing orientation on the mechanical characteristics, especially the modulus elasticity, of additive manufacturing (AM)—grade polyamide material. Selective laser sintering (SLS) technology was used to create tensile specimens composed of polyamide 12 (PA12). A specific type of specimen according to the ISO 527-2 standard for tensile specimens was studied to examine mechanical properties. The study looks at two batches of specimens exposed to tensile stress in various orientations inside the powder bed. Mechanical property evaluation utilizes a universal testing equipment, the Simadzu AGS-X. The comparison of horizontally and vertically printed samples attempts to determine if print orientation has a substantial impact on the mechanical qualities of the components
WEB SPEED CONTROL BETWEEN INPUT AND OUTPUT CATEPILLAR DEVICE ON CCV LINE USING PID AND SMC CONTROLLER
No full textThis paper presents speed and cable position control between caterpillar (pulling) device on CCV (Catenary Continual Vulcanization Line) production by Royle for production middle voltage cables using PLC controller CompactLogix L35E by Allen Bradley series and DC converters DCS 6RA80 series by Siemens with PID and sliding mode control (SMC). Input caterpillar device is master device on line its speed is regulated using PID from PLC. Output caterpillar as follower device is regulated using SMC with PID sliding surface which is defined equivalent control plus switching control. SMC controller also realized in PLC in discrete form. In this work was used a direct control method because it was measured current cable position all the time. State space model of system is given using Zero order hold (ZOH) discretization and sampling time was realized using the Timed Interrupt routine. Feedback of cable position is given from a non-contact sensor (SAG measure device) by Scholz placed on the vulcanization tube and it is used in the part of the routine for the output caterpillar. As the original machine is earlier production date, a reconstruction was made using modern components for the control and regulation. During the reconstruction, DC motor with a tachogenerator were change with DC motors with encoders, PLC software was developed and written, new electrical panel were made, and mechanical component was changed and installed. It was conducted redesign of some mechanical component to allow usage of implemented speed control method. After revitalization, the machine was successfully tested in cable production and the functionality of the installed components was experimentally proven. This revitalization was useful and the presented method has shown practical value in industrial applications for producing medium voltage cables
VIRTUAL REALITY ENVIRONMENT FOR TEACHING ASSEMBLY SEQUENCE ANALYSIS TO PRODUCTION ENGINEERING STUDENTS
No full textAssembly sequence analysis represents the first step in assembly process design and plays a very important role in achieving optimal production time and cost, which is of great importance in large-scale and mass production. There are several different approaches to address this issue. As a rule, they start from the analysis of product components and their mutual liaisons (contacts, i.e., mates or joints), followed by generation of all feasible assembly sequences and, finally, selection of the optimal sequence according to appropriate criteria. However, mastering these tasks can be challenging for students who encounter them for the first time, and particularly when physical interaction with the product is limited. To facilitate and enhance students’ understanding of these methods by making the learning process more intuitive and easier, while also assisting educators in effective teaching, the Virtual Reality (VR) technology can be used. This paper presents a VR-based learning workflow for teaching methods for assembly sequence analysis to production engineering students. The workflow contains predefined tasks that students follow in VR to achieve the intended learning outcomes without the need for significant manual effort. For this workflow several VR environments are developed. In addition to these environments, the paper presents the analysis of the students’ experiences in their utilization
Risk analysis of inlet pipeline in hydro power plant Perućica based on failure analysis diagram
No full textInlet pipeline in the Hydro power plant “Perućica” in Montenegro has been checked in 2024byNDTmethods with a focus on its branch and inlet elbows. In the lower and upper elbow of unit 7 indicationshavebeen detected during the first magnetic particle testing. At the lower elbow “A-side” a crack withlengthof500 mm and depth up to 20 mm was detected, classified as unaccetable. Unacceptable defects were alsofoundinside the upper welded joint in the pipeline branch, with length 150 mm and depth 7 mm, locatedat themidthickness from 14 mm to 21 mm. Having in mind potential catastrophic consequences in the case of afailure, the branch with defects was additionally analysed by means fracture mechanics parameters andstructuralintegrity assessment to estimate risk of its further use. Although material in both cases was not veryfavourable from the fracture mechanics point of view, both defects turned out to be safe for further operation. This conclusion is also based on the fact that there is no mechanism of crack growth (practically nocorrosionand fatigue). Anyhow, since the risk in the case of the inlet elbow was of relatively high level, repair weldingwas recommended and performed