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NUMERICAL ANALYSIS OF STATIC STRESSES IN PARTIAL HIP IMPLANT
Get PDFResearch presented here involves numerical analysis of stresses in partial hip implant subjected to static loads, for two cases of patient weight. The numerical analysis requires the development of 3D models that would accurately repre-sent real partial hip implant geometry, hence a reverse engineering approach via 3D scanning is also included. This combined approach provides reliable insight into the behaviour of partial hip implants under static load, while also exposing certain issues related to the application of this specific implant geometry at higher weight levels
Geometrical design of gears using motion analysis in cad software
No full textThe utilization of tools provided by CAD software has become an essential component of any design process in modern mechanical design. These tools provide a simplified design methodology that does not require expert knowledge for the design of complex mechanical parts. Gears, as one of the most used mechanical components, have precisely defined and well-understood several types of tooth geometry. However, different shapes of tooth profiles cannot be easily analyzed and designed without knowledge of mathematics and analytical geometry. With modern design tools, especially CAD software, that knowledge is not necessarily required in the design process. Engineers can simply define the relative motion of one component to produce all necessary parameters that define the shape and geometry of another component
OPERATIONAL CHARACTERISTICS OF THE COMBINED HEAT AND POWER PANT IN THE DISTRICT HEATING SYSTEM OF BELGRADE
No full textThe combined production of electricity and thermal energy (combined heat and
power or co-generation) is the most efficient and convenient approach to reduce
costs for energy at industrial power plants and district heating plants that use natural gas as fuel to produce thermal energy for various needs. This paper analyses
the operational characteristics of the combined heat and power plant, which has
been operating since January 1, 2021, at the Voždovac Heating Plant as part of the
Belgrade district heating system. The combined heat and power plant consists of
three gas engine units with a total nominal electric power of 10 MW and thermal
power of 10.1 MW, which use natural gas as fuel. The combined heat and power
plant is used for district heating and preparing domestic hot water while electricity is sold to the local electric grid. The analysis in this paper focuses on the
plant’s operational characteristics: the number of working hours, the total energy
consumption and energy production, the efficiency as well as the operational and
maintenance costs. Also, the impact of the drastic changes in the prices of natural
gas, electricity, and maintenance costs in the last year on the financial profitability
of the combined heat and power plant was analysed in particular
Proizvodnja biogasa
No full textУ циљу смањења зависности од фосилних горива и иско-
ришћења органских отпадних материјала значајно се развила индустрија
производње биогаса. Биогас је гориви гас који се добија разградњом ор-
ганских материја у анаеробним условима, при чему његов састав и својства
зависе од врсте сировине и избора одговарајућих процесних услова. Рела-
тивно је једноставан за складиштење, има високу топлотну моћ, и веома
је прихватљив као гориво са аспекта емисије гасова који изазивају ефекат
стаклене баште. У раду ће бити посебно обрађени: најважнији прописи и
стандарди из ове области, идентификација расположивости отпадних мате-
ријала и отпадне биомасе за производњу биогаса, својства биогаса, техничке
и технолошке карактеристике постројења за анаеробну обраду отпадних ма-
теријала, конструкционе карактеристике и техничка решења за производњу
биогаса. Такође, биће приказана и примена биогаса, могућности коришћења
отпадног муља из процеса производње биогаса, потенцијал за производњу
напредних биогорива и проблеми у одређивању потенцијала и могућности
коришћења биогаса у Републици Срби
Determining the Availability of Continuous Systems in Open Pits Using ANFIS and a Simulation Model
No full textThis paper presents a model for determining the availability of continuous systems at open pits using the neuro-fuzzy system. The concept of availability is divided into partial indicators
(synthetic indicators and sub-indicators). The presented model in relation to already existing models for determining availability uses a combination of the advantages of artificial neural networks and fuzzy logic. The case study addressed the I ECC (bucket wheel excavator–conveyors–crushing plant) system of the open pit Drmno, Kostolac. In this paper, in addition to the ANFIS model for determining the availability of continuous systems, a simulation model was developed. The obtained results of the ANFIS model were verified with the help of a simulation model that uses certain assumptions about the distribution of failures. This paper was created as a result of several years of field and theoretical research into the availability of continuous systems in open pits, and completes a cycle that consists of several published articles on the subject of modeling the behavior of these systems in real time using a time picture of the state, expert assessment, simulation and AI models, while respecting the multidisciplinarity of the problem (mining technological, mechanical, and information technological aspects). The developed ANFIS model is a key instrument for improving operational efficiency and resource management in the mining sector. Its ability to accurately predict the availability of the ECC system brings not only operational benefits through reduced downtime and optimized maintenance, but also a potential reduction in overall costs at coal open pits. Such an innovative model marks a significant step forward in the mining industry, especially when it comes to continuous systems in coal open pits
Environmental and Social Assessment of SHPP Mojanska 2 – Expertise
No full textM103 - The expertise is done for Deloitte Consulting co. The investor was EIB (European Investment Bank)
PRINTING ORIENTATION AND PLACE INFLUENCING THE COMPRESSIVE STRENGTH OF POLYAMID 12 SPECIMENS OBTAINED BY SLS TECHNOLOGY
No full textThis research aims to determine how the orientation and placement of printing impacts the compressive strength of specimens manufactured by Selective Laser Sintering (SLS).
The research includes compressive specimens in which the CAD model dimensions are selected according to the ISO 604 standard, and specimen geometry Ø10x20 mm in bulk. All specimen configurations are additively manufactured in two different printing orientations, horizontal and vertical, and printed in the middle and on the edge of the powder bed. All specimens are additively manufactured using Polyamide 12 (PA 12) material on a Fuse 1 device (FormLabs, located in Summerville, MA). Compressive strength testing was carried out using a Shimadzu AGS-X universal testing machine (Shimadzu Corp., Kyoto, Japan)
Digital Transition of the Maintenance Process: Case of Rail Transport Company
No full textDigital transformation of business activities has outgrown from
competitive advantage to necessity in recent years. Evolution of
information and communication technologies (ICT) has created
the world where electronic business (E-Business), document
management systems (DMS) and enterprise resource planning
(ERP) solutions have become standard, even for micro, small
and medium enterprises (MSME) in developing countries.
Modern businesses focus on implementing data analysis,
business intelligence (BI) and even artificial intelligence (AI)
concepts in their everyday activities, thus the digitalization of
business activities is simply considered as default. Nevertheless,
public companies in developing countries fall behind and
struggle in this transformation process, as usual. Due to various
reasons, they are still in the phase of digitalization, rather than
implementing advanced solutions. Any organizational change
demands unfreezing and mindset redirection, among both
management and executors, which is always challenging,
especially in the public sector. This paper aims to explain the
preconditions and benefits of digital transition of the train
maintenance process, and key challenges in such transformation
Применение принципа Понтрягина в задачах минимизации массы балки, испытывающей связанные изгибные, крутильные и продольные колебания
Get PDFPredavanje po pozivu na Seminaru "Rumjancev" Katedre za teorijsku mehaniku i mehatroniku Fakulteta za mehaniku i matematiku Moskovskog državnog univerziteta "Lomonosov
From Innovation to Standardization—A Century of Rolling Bearing Life Formula
No full textThis review paper is an homage to Arvid Palmgren’s pioneering paper on rolling bearing service life to highlight its relevance a century later. It follows the evolution of bearing service life theory from Palmgren’s fundamental research to the contemporary international standard ISO 281. Palmgren’s theory, based on the previously published papers of Stribeck and Hertz, laid the basis for the later development of bearing service life assessment methodology. Based on the Weibull theory of probability of damage, Lundberg and Palmgren introduced stochastic elements to explain the effect of reliability on bearing service life prediction. Harris and Ioannides, who made a significant contribution to the revision of the international standard on rolling bearing load rating and rating life are mentioned as well. Zaretsky’s critical analysis also was not neglected in this review, due to a different approach respecting the original influence of material properties and bearing performances. Despite standardization, ongoing research by leading advanced bearing industries and academic institutions continues to refine methodologies for service life assessment. Through a comprehensive review and analysis, this paper offers insight into the current state of bearing service life theory, highlighting the collaborative efforts bringing progress in this field