Machinery - Repository of the Faculty of Mechanical Engineering, University of Belgrade
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Green Buildings, Energy Efficiency and Raising Awareness About Environmental Protection
No full textThe main goal of this research is the integration of green building practices, energy
efficiency measures, and raising awareness about environmental protection as
crucial in addressing the pressing challenges of climate change and resource
depletion. This research encompasses the correlations of these elements and their
results as impact on sustainable development. Green building principles
emphasize the use of eco-friendly materials, energy-efficient designs, and
sustainable construction techniques to minimize environmental impact. Raising
awareness about environmental protection require researching and positive
practice analysing in order to be able for making optimal eco-conscious decisions.
The goal is mitigating climate change, conserving natural resources, and creating
healthier living environments. This manuscript underscores the necessity of
integrating these strategies to achieve long-term sustainability goals and foster a
greener, more resilient future for generations to come. Two the most efficient
world’s models of green buildings are presented in this manuscript, with its
particular results in energy efficiency achievements
A comprehensive bibliometric analysis and assessment of high-impact research on the berth allocation problem
No full textThis paper aims at the identification and assessment of High-Impact Research Papers (HIRPs) on the Berth Allocation Problem (BAP) research at marine terminals. The BAP objective is to optimally assign and schedule ships at berthing positions along a quay, as well as to determine the berthing times and positions of ships at a port. The purpose of this study is to facilitate the work of the relevant research community and ultimately promote the research quality in this area. In meeting this objective, the paper utilizes a systematic and fair method to determine HIRPs of the BAP, which is based on the h-index and the g-index. An in-depth bibliometric analysis of the identified studies reveals their key features and characteristics. The analysis was conducted using the VOSviewer and bibliometrix R-package software programs. The main findings provide many useful insights on the BAP research development. The adopted approach and associated analysis results present an up-to-date detailed picture of the BAP research and constitute a valuable tool for its applications into other relevant research areas. The common trends in the reviewed HIRPs and important future research needs are discussed in a comprehensive manner. This survey study can be viewed as the first attempt for a comprehensive bibliometric survey of the high-impact BAP literature, which will be of a great value to researchers and industry practitioners. Furthermore, the proposed methodology for the identification of HIRPs can be used not only for the BAP research but for the literature surveys in other domains as well
Maintenance and optimization of biogas production: Ensuring material quality
No full textEffective biogas production hinges on the efficient removal of contaminants like plastics, glass, metals, and oversized particles from the organic substrate. The presence of these impurities not only affects the quality of the final digestate or compost but can also lead to operational inefficiencies and increased maintenance costs. Implementing advanced separation technologies—whether before, during, or after the digestion process—is critical for maintaining consistent biogas yields and preventing damage to digestion equipment. The quality of input materials becomes especially crucial when the end product is intended for agricultural or horticultural applications, where even trace contaminants can impact soil health and crop productivity. By optimizing the preparation of raw
materials and incorporating both dry and wet impurity removal systems, biogas facilities can improve operational stability and reduce downtime. Furthermore, such optimizations facilitate more sustainable waste management by ensuring a stable, high-quality biogas output and a digestate rich in nutrients and free from harmful contaminants
Environmental and Social Assessment of SHPP Mojanska 1 - Expertise
No full textM103 - The expertise is done for Deloitte Consulting co. The investor was EIB (European Investment Bank)
Averaged Nystr\" om interpolants for the solution of Fredholm integral equations of the second kind
No full textADDITIVE TECHNOLOGIES AND APPLICATION OF THE STEP-NC PROTOCOL
Get PDFU radu je predstavljen pristup za primenu STEP-NC protokola u aditivnoj proizvodnji. Koristi se sta-ndard ISO 10303 AP238 koji omogućava implementaciju geometrijskih informacija o slojevima do-davanja materijala kao ulaznih podataka za generisanje STEP-NC programa. Prikazana je i me-todologija za primenu STEP-NC protokola u aditivnoj proizvodnji. Za potrebe verifikacije i simulacije generisanih programa za aditivnu proizvodnju koristi se okruženje STEP-NC Machine i sopstvene konfigurisane mašine za dodavanje materijala u okviru ovog softveraThe paper presents an approach for applying the STEP-NC protocol in additive manufacturing. The ISO 10303 AP238 standard is used, which enables the implementation of geometrical information about material addition layers as input data for the generation of STEP-NC programs. The methodology for applying the STEP-NC protocol in additive manufacturing is also given. For verification and simulation of the generated programs for additive manufacturing, the STEP-NC Machine environment and us own configured machines for additive manufacturing within this software are use
Failure analysis of welded joint with multiple defects by extended Finite Element Method and Engineering Critical Analysis
No full textFailure analysis of welded joint with multiple defects was performed taking into account the effect of all defects, not just a dominant one. Four cases of multiple defects in welded joint under the uniaxial tensile loading were investigated using extended Finite Element Method. Two-dimensional Finite Element Models were made according to the tensile specimens with initial crack located in a critical area of welded joint. For each multiple defects case, numerical simulation was performed with three initial crack depth. Engineering Critical Analysis was made using Failure Assessment Diagrams for each defect that was determined as critical for its welded joint case. Numerical simulation showed that the geometry of the most prominent one from a point of view of structural integrity. It was concluded that the vertical misalignment in combination with a secondary defect, had the most adverse effect which can lead to failure of welded structure
Influence of Aging on the Flexural Strength of PLA and PLA-X 3D-Printed Materials
Get PDFThe 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 advanced materials. The traditional approach to analyzing the mechanical properties of a material using a three-point bending test has the disadvantage that it provides only global information about the material’s behavior. This means that it does not provide detailed insight into the local strain distribution within the material. However, the 2D Digital Image Correlation (DIC) method offers additional insight, especially in terms of strain localization. DIC is an optical technique that measures full-field displacements and strains on the surface of a sample. PLA and enhanced PLA-X material were utilized to create three-point bending samples. The aim of this paper was to analyze and compare the influence of aging on the mechanical properties of PLA and enhanced PLA-X materials using three-point bending coupled with the DIC method. The results showed statistically significant differences between the PLA and PLA-X, for both the new and aged materials. The aged PLA samples had the highest average value of maximal force around 68 N, which was an increase of 8.8% compared to the new PLA samples. On the other hand, the aged PLA-X material had an increase of 7.7% in the average maximal force compared to the new PLA-X samples. When comparing the two materials, the PLA samples had higher maximal force values, 6.2% for the new samples, and 7.3% for the aged samples. The DIC results showed that both the new PLA and PLA-X samples endured higher strain values at Points 1 and 2 than the aged ones, except for the aged PLA-X sample at Point 2, where the new sample had higher strain values. However, for the first 5 min of the experiment, both materials exhibited identical behavior, after which point significant differences started to occur for both materials, as well as at Points 1 and 2. A more profound comprehension of the biomechanical characteristics of both PLA and PLA-X material is essential to enhance the knowledge for potential biomedical applications. The DIC method was found to be a powerful tool for analyzing the deformation and failure behavior of samples and for complementing the traditional approach to material testing
Computation of pairs of related Gauss-type quadrature rules
No full textThe evaluation of Gauss-type quadrature rules is an important topic in scientific computing. To determine estimates or bounds for the quadrature error of a Gauss rule often another related quadrature rule is evaluated, such as an associated Gauss-Radau or Gauss-Lobatto rule, an anti-Gauss rule, an averaged rule, an optimal averaged rule, or a Gauss-Kronrod rule when the latter exists. We discuss how pairs of a Gauss rule and a related Gauss-type quadrature rule can be computed efficiently by a divide-and-conquer method
HARD HAT DETECTION FOR SAFETY PURPOSES BY USING YOLOV9
Get PDFEnsuring the safety of workers at workplaces is a crucial task for every company. The usage of personal protective equipment represents the basic form of protection. Hard hats are very useful in protecting head from injuries. However, workers often neglect the importance of wearing safety helmets and do not wear them. Systems for monitoring and detecting unsafe behaviors can be very helpful for maintaining security. For that purpose, this research examines the success of the application of the latest YOLO algorithm for detecting the presence of safety helmets on workers that can be applied in those systems. Two models with different numbers of parameters are trained for this purpose – YOLOv9c and YOLOv9e. The results showed that YOLOv9c model achieved mean average precision of 97.2%, 93%, and 92.9% in training, validation, and testing, respectively, while YOLOv9e reached slightly higher mean average precisions of 97.5% in training, 93.4% in validation and 93.4% in testing