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The importance of sintering is explained in this abstract, with a focus on how it helps achieve the precise fit, structural stability, and natural aesthetics that are necessary for dental restorations to be effective. A crucial method in the creation of dental prostheses, especially dental bridges, is the sintering process. Through a regulated heating procedure, dental ceramic particles are fused together to create a final product that is both visually beautiful and extremely durable. The ideal mechanical qualities, such as strength and biocompatibility, are ensured by the high-temperature amalgamation of ceramic particles. A dimensional examination of the collected dental samples can be carried out by the 3D scanning process, and a comparison with the 3D models that served as their foundation is made. The 3D scanner used in this research is the Atos Core 200, while the comparison with the 3D model was made in the GOM Inspect program (GOM Metrology GmbH, Braunschweig, Germany). Based on the measurements obtained by 3D scanning, the average deviations characteristic of individual technological processing procedures were obtained. This approach enabled more precise model-making and savings on materials.

The precision of 3D printing in the fabrication of sintered dental metalwork is critical for successful clinical outcomes. However, during the initial trial of these metal components on the patient, a dimensional discrepancy often manifests itself, indicating a poor fit despite being modeled from precise intraoral scans. This necessitates additional corrections or reprinting, thus extending the duration of treatment, increasing costs, and raising concerns about the reliability of 3D printing and subsequent processing techniques. This study aims to quantitatively analyze the dimensional changes in sintered dental metalwork from the original intraoral scan to the final product and to evaluate whether these changes are influenced by the complexity of the metalwork design. Using a 3D scanner (Atos Core 200, GOM, Germany), the dimensions of the sintered metalwork were compared to the corresponding CAD models. Preliminary results indicate significant dimensional deviations, particularly in more complex designs, underscoring the need for improved accuracy in the 3D printing process to enhance clinical outcomes and efficiency.

The Optical methods can be highly useful for analysing Pipe Ring Tensile Specimens (PRTS) since they offer an accurate and non-destructive method of evaluation. Optical technologies have several uses, such as Digital Image Correlation method (DIC method), thermal imaging camera, and 3D scanning. The DIC method is used to measure stresses and full-field displacements. DIC analyses a speckle pattern that is applied to the surface of the specimen and can provide detailed information on strain distribution, deformation gradients, and likely failure spots. An infrared thermal imaging camera can be used to detect defects in pipe specimens, such as fractures or delamination, by tracking the distribution of surface temperatures. Temperature anomalies can indicate areas of intense stress or material degradation. A 3D scanner is a device that uses the shape, size, and texture of physical objects to digitise them into three-dimensional digital representations. The investigation focused on five distinct PLA PRTS. The study describes how to evaluate PLA PRTS using DIC method, thermal imaging camera, and a 3D scanner. The evolution of strain was monitored using the 3D Digital Image Correlation approach. Using a thermal imaging camera, the temperature field change in the PRTS was investigated during the test. In order to verify the cross-sectional shape of the PRTS after a fracture, 3D scanning was performed on each specimen.

The integration of 3D printing technology into orthopedic practice addresses the critical problem of enhancing surgical precision and improving patient-specific treatment. Traditional orthopedic methods often involve generic implants and extensive preoperative planning, which can lead to suboptimal fit, prolonged surgery times, and varied patient outcomes. To solve this problem, patient-specific 3D anatomical models and custom implants can be used. High-resolution imaging data from patients can be converted into 3D-printed models, allowing for detailed preoperative planning and the creation of implants tailored to individual anatomical structures. This method also uses biocompatible materials and advanced printing techniques to ensure structural integrity and functionality. The use of 3D-printed models facilitated an enhanced preoperative understanding of complex anatomies, leading to reduced operative times and increased surgical precision. Customized implants result in better fit and integration with the patient's body, contributing to faster recovery times and higher patient satisfaction. Case studies indicate that this approach minimizes complications and optimizes overall orthopedic care. Despite promising results, challenges such as regulatory limitations, cost considerations, and the need for interdisciplinary collaboration remain. However, ongoing research and technological developments are expected to further refine these applications, paving the way for greater adoption and more widespread benefits in orthopedic practice.

Fracture mechanics, a fundamental field in materials science and engineering, deals with the study of crack initiation, propagation, and fracture resistance of materials. Traditional methods in fracture mechanics analysis often rely on analytical or numerical approaches, which may have limitations in capturing crack behavior under various loading conditions. To overcome these challenges, the 2D Digital Image Correlation (2D-DIC) method, a noncontact, full-field measurement technique, is employed to precisely quantify displacement and strain values. This paper investigates the application of the 2D-DIC method in the field of fracture mechanics. Through an experimental investigation that involves fracture toughness testing, crack growth monitoring, and fatigue crack propagation analyses, the effectiveness of 2D-DIC in capturing crack behavior is demonstrated. The results showcase the method's ability to accurately track crack propagation, providing valuable insight into crack growth mechanisms, and offering new data for understanding fracture mechanics phenomena. This paper contributes to advancing the field by highlighting the utility of 2D-DIC as a powerful tool for studying crack behavior and improving the overall understanding of fracture mechanics.

Energy efficiency plays a critical role in achieving economic, social, and environmental sustainability. This paper provides an overview of the current state of energy efficiency in Serbia, focusing on the challenges, opportunities, and potential pathways towards a more sustainable energy sector. The country has recognized the importance of energy efficiency in improving energy security, reducing costs, and complying with international environmental standards. However, Serbia faces significant challenges, including a lack of awareness of the benefits of energy efficiency, insufficient financing, and policy support for energy-efficient technologies. Nevertheless, Serbia possesses considerable potential for energy-efficient technologies and practices, particularly in the residential and industrial sectors. By promoting energy efficiency, Serbia can reduce energy costs, improve energy security, and contribute to global climate-change mitigation efforts. The paper also highlights the global challenges faced by the energy sector, such as rising energy demand, climate change, pollution reduction, and energy poverty, emphasizing the need for greening the energy sector and investing in renewable energy sources. The energy consumption trends, energy intensity, energy productivity, and share of renewable energy sources in Serbia were analyzed using EuroStat data. The paper concludes by emphasizing the importance of ambitious goals, public awareness, modernizing infrastructure, and securing adequate financing to drive energy efficiency improvements in Serbia. This overview serves as a valuable resource for policymakers, researchers, and stakeholders interested in promoting sustainable energy practices in Serbia and fostering a transition towards a more energy-efficient and environmentally friendly energy sector.

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 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

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 exposed to extreme temperatures and environmental conditions, the temperature variations that occur must be taken into account. In this study, small-scale specimens of the thermoplastic polymer material polylactic acid (PLA) were printed using an FDM printer while a thermal imaging camera was used to record the temperature changes during the printing process. The aim was to determine the temperature changes during each step of the printing process of small specimens and to create a future model for testing the temperature distribution.

Today, the waste material obtained by 3D printing operations presents significant challenges due to the increasing global adoption of this technology, leading to serious environmental implications. The generation of plastic waste from unsuccessful prints and end-of-life products is a growing concern, impacting the circular economy. With a 26% annual growth rate in additive manufacturing, the amount of waste is rapidly increasing, necessitating effective waste management strategies. However, 3D printing offers advantages in waste reduction compared to traditional manufacturing methods, with only 40% waste generation compared to subtractive technologies and much of the waste being recyclable. The challenges of waste material obtained by 3D printing are numerous and require a comprehensive approach to waste management and recycling. Moreover, leveraging the abundant opportunities for reusing materials and developing sustainable composite filaments, 3D printing can contribute to environmental sustainability and the principles of circular economy.

Eco-art and recycling initiatives often involve comprehensive community engagement and participation in specific conditions. This paper explores the synergy between eco-art and recycling processes, as an optimal strategy to advance environmental preservation, alongside the integration of land art with ecological concepts. As environmental concerns escalate, the integration of ecoartistic measures and practices with recycling initiatives emerges as a potential to enhance environmental consciousness and sustainability. The study delves into the interconnectedness of these two disciplines, examining how the creative expression of eco-art can amplify the impact of recycling efforts and activities, leading to heightened environmental awareness and conservation. By detailed examination of the intersections of these creative and ecological disciplines, the research aims to contribute insights into innovative approaches that simultaneously harmonize artistic expression and environmental conservation aspect, with the final important task of protecting our planet and ensuring sustainable development.

The pantograph’s purpose is to transfer electrical power from the overhead contact line to the train’s electric propulsion unit. To perform its function adequately, it is necessary to maintain the static contact force between the pantograph and the contact line within the values prescribed by appropriate standards for the entire extension range of the pantograph. The requirement to reach high contact lines complicates the kinematic scheme because the deviation of the trajectory of the pantograph’s collector head from vertical is also prescribed by standards. Further, the structural design of the pantograph is challenging because the greater slenderness ratio of the structure makes it difficult to meet the requirements in terms of stiffness and resistance to vibrations. While at low speeds aerodynamic forces are usually neglected, in high-speed pantographs, they have a significant impact and it is necessary to compensate for them. An aggravating circumstance is the requirement that the pantograph should work in both knuckle-downstream and knuckle-upstream directions. This paper aims to present the development of a high-speed high–reach pantograph that is developed through the cooperation of company Minel General Electric and the University of Belgrade – Faculty of Mechanical Engineering as well as to present innovative designs of gravitational and aerodynamical compensations that enabled the satisfaction of requested requirements in terms of geometric and static performance.

A global problem for industrial plants that contain process equipment operating under high pressure is the assessment of the integrity of the equipment, specifically the pipelines. Standard procedures for determining fracture mechanics parameters (ASTM E1820) for materials used in pressure piping construction cannot be applied to most thin-wall pressure components. One of the solutions to this problem is the introduction of new procedures and geometries of test specimens. In order to understand the nature of the behavior of the specimens and to determine the parameters whose critical values are important for integrity assessment of the pipeline under pressure, a detailed analysis of the model of the non-standard ring-shaped specimen is necessary. This paper will present the results of the analysis of fracture mechanics parameters obtained by the finite element method using the Simulia Abaqus software package. The properties of the material used in the software correspond to the properties of the P235TR1 pipeline material obtained by tensile testing on cylindrical samples with initial crack. The ratio of crack length (a) to sample width (W) corresponds to standard sample geometries and varies from a/W = 0.4 to a/W = 0.6. The values obtained from SENT (Single Edge Notched Tension) models with the same cross-section and a/W ratio were taken as reference values in relation to which the comparison is made. As a result of this research, the ratio of fracture mechanics parameters of the ring-shaped model (Pipe Ring Notched Tension – PRNT specimen) with a crack and the SENT model was obtained. The values of the J-integral were also obtained, distribution of values along the crack front does not correspond to the profile obtained on the SENT model. As a result of this test, a procedure for determining the critical value of the J-integral for models corresponding to the tested P235TR1 pipe samples was established, which is an important step in establishing a new procedure for

Conventional tensile testing is most commonly used for determining the basic mechanical properties of the material. However, this approach is challenging for in-depth analysis of material behaviour, especially related to heterogeneous materials. The Digital Image Correlation (DIC) method is a contactless optical method that overcomes the constraints of traditional experimental methods (e.g., strain gauge) and allows for full-field displacement and strain measurement. The paper specifically covers 2D-DIC application on tensile testing thin flat specimens prepared using cotton textile with 130 g/m2 density. Results show significant differences in von Mises strain values over the surface of the specimen, ranging from 8 to 24 %. The application of 2D-DIC in this case shows the significance of full-field analysis, as conventional usage of the tensile test would have missed the difference in mechanical properties of adjacent areas on the same specimen. 2D-DIC provides high spatial resolution, accuracy, real-time data acquisition, and visualization, making it a valuable tool for characterizing mechanical properties of thin flat specimens and understanding deformation mechanisms.

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 thermoplastic polymer material acrylonitrile butadiene styrene (ABS) was selected in the form of both filaments and ABS-like resins to investigate and compare the mechanical properties through a series of different tests. ABS-like resin material is commercially available, but it is not a sufficiently mechanically studied form of the material, which leads to the rather limited literature. Considering that ABS resin is a declared material that behaves like the ABS filament but in a different form, the objective of this study was to compare these two commercially available materials printed with three different 3D printers, namely Fused Deposition Modelling (FDM), Stereolithography (SLA) and Digital Light Processing (DLP). A total of 45 test specimens with geometries and test protocols conforming to the relevant standards were subjected to a series of tensile, three-point bending and compression tests to determine their mechanical properties. Characterization also included evaluation of morphology with 2D and 3D microscopy, dimensional accuracy of 3D scans, and Shore A hardness of each material and 3D printing process. Tensile testing results have shown that FDM toughness is 40% of the value for DLP. FDM elongation at break is 37% of DLP, while ultimate tensile stress for SLA is 27% higher than FDM value. Elastic modulus for FDM and SLA coincide. Flexure testing results indicate that value of DLP flexural modulus is 54% of the FDM value. SLA strain value is 59% of FDM, and DLP ultimate flexure stress is 77% of the value for FDM. Compression test results imply that FDM specimens absorb at least twice as much energy as vat polymeri

Different pipe manufacturing techniques, such as the manufacture of seamless pipes in the oil sector employing a conical shaft, necessitate data on the circumferential strain and stress condition of the pipe. The purpose of this study was to evaluating the displacement, strain, and stress behavior of a pipe ring tensile specimen (PRTS) in the hoop direction, as there was a lack of a standardized testing methodology. Five single S235JRH steel PRTS were tested for the study. The study describes how to test S235JRH steel PRTS with a Digital Image Correlation approach. The 3D Digital Image Correlation technique methodology was used to record the evolution of the strain. In the break zone and almost equivalent locations, all Single PRTS fractured. The experimental ultimate strength value's deviation value (also known as the real stress value) is greater than the theoretical ultimate strength value.

The three-point bending test is a widely used and important method for evaluating the mechanical properties of materials. Its versatility, applicability, and ability to provide valuable information on flexural strength, stiffness, and fracture toughness make it a valuable tool in materials science, engineering, and biomedical research. Digital Image Correlation (DIC) provides a high resolution and full-field measurement of deformation during the bending process. DIC also allows for the calculation of strain fields, which can be used to determine material properties such as Young's modulus and Poisson's ratio. This is particularly important in understanding the strain distribution and identifying potential failure mechanisms in the material. In this paper, the potential application of the 2D Digital Image Correlation method on three-point bending tests is presented.

In order to develop a non-standard method for determining the resistance to fracture and damage of pipeline materials, a new geometry of ring-shaped specimens with sharp notches or cracks has been defined. The need to develop a new method for testing of the specimens cut from the pipes arises due to the difficulties in determination of fracture mechanics parameters on thin-walled pressure pipelines, especially those with a smaller cross-section, by application of the standard procedures/specimens. Previous studies dealing with the topic of pipeline testing by non-standard methods are presented in the introductory part of the paper. In the experimental part of the research, tests on PRNT (Pipe Ring Notched Tension) and SENT (Single Edge Notched Tension) specimens are performed. Samples of these specimens were produced by SLS (Selective Laser Sintering) technique of additive production from PA12 (polyamide PA 2200) material. For the purpose of this study, a tool that is protected at the national level (in Serbia) as intellectual property is used for testing of the ring-shaped PRNT specimens. Tensile testing of both types of specimens is monitored by Aramis GOM 2M system; its operation is based on the method of digital image correlation, DIC. Additionally, finite element analyses are conducted on the PRNT and SENT geometries, enabling the calculation of the fracture mechanics parameter – Stress intensity factor K. It is concluded that the presented procedure based on the PRNT specimen has a good potential for use as a non-standard method for fracture resistance examination of pipeline materials. It can be performed on the specimens cut directly from the pipes (new or from exploitation). The dependence of the fracture resistance on the stress concentrator size is not pronounced, which means that the results depend dominantly on the material properties, rather than on geometry.

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 compared to subtractive computer numeric controlled methods and conventional dentistry techniques. Applied digital workflow in dentistry embraces data acquisition with intraoral scanning, object design in CAD software and 3D printing with corresponding materials on adequate 3D printer. With the utilization of the 3D techniques, it is possible to make adequate digital models and to reproduce them with enough precision, which led to a transformation in dentistry practice and a wide range of present and possible future applications. An important benefit regarding 3D printing in dental practice is the fact that various materials can be used, such as polymers, resins, metals, ceramics etc., even multiple different materials during one production process, if needed. On the other side, there is a handful of available AM techniques depending on the model geometry complexity and desired accuracy. Implementation of 3D technologies proved to be beneficial in laboratory and clinical settings, surgical and restorative dentistry, and continues to expand in research and dental education. The aim of this article was to give one perspective and to review the techniques, materials and current applications of 3D printing in dentistry. As well, significance of waste and recycling of materials used for printing in this area is pointed out.

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, numerical, thermal and dimensional data, with the aim of improving and optimizing the result. The first part of this research is based on the observation of temperature changes with a thermal imaging camera during the fused deposition modeling printing process and during the cooling process after printing. Specimens of polylactic acid and polylactic acid-X improved with second-phase particles were prepared to compare the thermal and dimensional properties of the two materials. The obtained results determined the characteristic temperature behavior of the materials. In the second part of the research, a 3-D optical scanner was used to verify the stability and accuracy of the printed specimens over time. The proposed measurement period showed that stabilization of the parameters takes place, and further follow-up should be performed thereafter.

Today, cosmetics have become an unavoidable feature of the modern way of life of individuals. The size of the global cosmetics market is estimated at 380.2 billion dollars in 2019 and is projected to reach 463.5 billion dollars by 2027, with a CAGR of 5.3% from 2021 to 2027. According to the client's request, a study of comparing three different cosmetic devices (ProLiftftr, MagicEye, MiniMeso) was conducted at the Centre for Optical Measurements of the Faculty of Mechanical Engineering, University of Belgrade. By using the images obtained with the PeakTech 5620 thermal imaging camera, the effects and quality of the device's effect on the skin were pointed out. All three devices have cosmetic performance and after a certain number of treatments show improvement in the form of skin tightening, wrinkle reduction, and reduction of swelling around the eyes, but one stands out in terms of application and treatment on the skin. To be specific, the device Proliftfrf has the best properties, which after moving the probe from the place of skin treatment allows faster cooling and a more pleasant treatment without burning and overheating. In addition, it can be seen that the Proliftfrf cosmetic device compared to the other two MiniMeso and MagicEyes has software that is easier to use and allows quick access, and clearly defined items, which increases the speed of work in salons, and allows more customers. This device achieves better treatment results in a shorter of therapy and thus increases the number of satisfied clients.

For various pipe manufacturing methods, data on the pipe's strain and stress state in the circumferential direction is necessary (e.g. in the oil industry, the process of manufacturing seamless pipes with a conical shaft). The purpose of this research is to create a method for determining the strain and stress behaviour of Pipe Ring Tensile Specimens (PRTS) in the hoop direction. The absence of official methods for assessing a PRTS suggests that it could be developed. The implementation of the digital image correlation approach for evaluating plastic PRTS is discussed in this research. A specially constructed steel instrument with two D blocks is used to test PRTS. Two D-shaped mandrels are fixed on the tensile tool and tensile testing equipment, and a 3D printed PRTS is placed over them. The three-dimensional Digital Image Correlation (3D DIC) approach was used to capture the strain evolution in the gage length of the specimens. All specimens are 3D scanned to evaluate the geometry of the PRTS cross-section following fracture. Six groups of PRTS were studied, with three different filling percentages (60, 90, and 100 percent) and two different geometric kinds (Single and Double PRTS). The results reveal that the kind and percentage of filling, as well as the printing method, affect material behaviour; however, the methodology using a DIC system, 3D printer, and scanner is an excellent tool for mapping entire strain fields in PRTS and thereby defining pipe mechanical properties.

Fused deposition modelling is, among the other additive manufacturing processes, one of the most frequently used three-dimensional printing technologies, because of its ease of use, high speed in production and low cost of the final part. Printing processes and finished parts are often examined and characterized using various techniques, for gathering the mechanical, numerical, thermal, dimensional data, with goal to improve and optimize the outcome. The first part of this research is based on the following the temperature changes using thermal imaging camera during fused deposi- tion modelling printing processes and during cooling process after printing is finished. Specimens were made from polylactic acid and polylactic acid - X improved with second-phase particles, in order to compare thermal and dimensional characteristics of both materials. Obtained results determined characteristic temperature behavior of materials. The second part of research employed optical 3D scanner for verification the stability and accuracy of printed specimens over time. Proposed period of measuring has shown that stabilization of parameters is taking place, and further follow-up should be done afterwards.

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 experimentally analyze impact forces and simulate conditions during different fight punches mechanical installment was made. Aramis system is used to measure the displacement fields and the distribution of deformations which occur on the neck over the entire analyzed area based on the correlation of digital images. On this manner better understanding of behavior of both materials and structures during the action of the impact forces and loading is obtained. This information can further be used in researches related to the development of helmets used in martial arts which would influence reduction of values of neck deformations in athletes.

Data on the strain and stress status of the pipe in the circumferential direction are required for various pipe manufacturing procedures (e.g., in the oil business, the process of manufacturing seamless pipes with a conical shaft). The aim of this study is to develop a procedure to determine the strain and stress behavior of Pipe Ring Tensile Specimens (PRTSs) in the hoop direction, as there are a lack of official standardized methods for testing PRTS. This paper discusses the application of the Digital Image Correlation method for testing plastic PRTSs. PRTSs are tested using a specially designed steel tool with two D blocks. A 3D-printed PRTS is placed over two D-shaped mandrels, which are fixed on a tensile tool and tensile testing machine. The strain evolution in the gage length of the specimens is captured using the three-dimensional Digital Image Correlation (3D DIC) method. To check the geometry of the cross-section of the PRTS after fracture, all the specimens are 3D scanned. For the study, six groups of PRTS are analyzed, consisting of three filling percentages (60, 90, and 100%) and two geometry types (Single and Double PRTS). The results show that the type and percentage of filling, as well as the method of printing, affect the material behavior. However, the approach with the DIC system, 3D printer, and scanner shows that they are effective instruments for mapping complete strain fields in PRTS, and thus are effective in characterizing the mechanical properties of pipes.

Boilers are one of the most used units for both heat generation plants and industry systems. Their operation is subjected to different working loads and maintenance requirements. Exploitation experience points out critical boiler zones where failures and break downs typically occur. This paper analyzes critical zones in hot water fire-tube boiler. Experimental procedure was performed on the model of this type of boilers and its critical element. The tube plate of hot water boiler was identified as the most critical one. Experimental analysis and numerical model verification were performed using Aramis system based on 3-D digital image correlation method. Numerical analysis was done in ANSYS software package and verification of results was done based on measurements obtained by strain gauges and local measurements performed by the Aramis system. Stress-strain analysis indicates the critical zones of boiler tube plate. The character of change parameters such as strain and stress occurring in the critical zones can be verified both by experimental and numerical data. The paper presents a novel approach in experimental and numerical analyses that can be conducted in similar units and used for existing unit optimization, as well as for new product testing on different loads and provide opportunity for further development and improvement for practical industrial application.

After primary treatment of localized prostate carcinoma (PC), up to a third of patients have disease recurrence. Different predictive models have already been used either for initial stratification of PC patients or to predict disease recurrence. Recently, artificial intelligence has been introduced in the diagnosis and management of PC with a potential to revolutionize this field. The aim of this study was to analyze machine learning (ML) classifiers in order to predict disease progression in the moment of prostate-specific antigen (PSA) elevation during follow-up. The study cohort consisted of 109 PC patients treated with external beam radiotherapy alone or in combination with androgen deprivation therapy. We developed and evaluated the performance of two ML algorithms based on artificial neural networks (ANN) and naive Bayes (NB). Of all patients, 72.5% was randomly selected for a training set while the remaining patients were used for testing of the models. The presence/absence of disease progression was defined as the output variable. The input variables for models were conducted from the univariate analysis preformed among two groups of patients in the training set. They included two pretreatment variables (UICC stage and Gleason's score risk group) and five posttreatment variables (nadir PSA, time to nadir PSA, PSA doubling time, PSA velocity, and PSA in the moment of disease reevaluation). The area under the receiver operating characteristic curve, sensitivity, specificity, positive predictive value, negative predictive value, and predictive accuracy was calculated to test the models' performance. The results showed that specificity was similar for both models, while NB achieved better sensitivity then ANN (100.0% versus 94.4%). The ANN showed an accuracy of 93.3%, and the matching for NB model was 96.7%. In this study, ML classifiers have shown potential for application in routine clinical practice during follow-up when disease progression was suspected.