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In the course of the last few years, interest in the development of smart cities and progress of smart buildings has increased significantly. This development has been significantly increased due to the development of new technologies, innovative functional materials, electronic components and other products. At the same time, it is imperative to use those products that contribute to the preservation of the environment, and above all to energy saving. Thus, new technologies are becoming increasingly attractive, such as the one based on OLED (Organic Light Emitting Diode) technology, which is used in the production of mobile phones, tablet computers, other devices, as well as light sources. Although this technology has been generally known for more than half a century, commercial application of OLED components was not possible due to insufficient efficiency of products based on it. However, the continuous improvement of characteristics and efficiency enabled their more significant application in the past few years. The aim of this work is to provide adequate information about the possibilities of applying some innovative technologies in the planning and development of smart cities. Especially, becoming more familiar with the basic properties and application possibilities of OLED devices can lead to the life quality improvements of city spaces users.

A detailed analysis of the accident that occurred at the flotation tailings storage facility (TSF) at the inactive mine “Stolice” in 2014 is provided in this paper. All factors that caused the accident have been analyzed, with a review of the consequences of the accident, their accident class according to the Global Industry Standard on Tailings (GISTM), and the implemented measures to rehabilitate the TSF and the surrounding area after the accident. It has been concluded that the TSF had not been properly maintained even before the accident occurred and that the unfavorable weather conditions in Serbia in the May of that year contributed to the filtration disturbance and multiple tailings spillages from the TSF. It has been stated that the consequences according to the GISTM span from “low” to “significant”, with the group of environmental consequences having the highest rank (3). Although the accident occurred without recorded human casualties, with the damage being of a local nature, it is considered one of the most significant accidents at a TSF in Serbia in the last 20 years. The reconstructed TSF is considered stable now, with a low-to-medium risk of failure.

One of the prerequisites for the safe exploitation of surface mines is the stability of the working and final slopes of the mine. In order to ensure this, it is necessary to carry out detailed field and laboratory geomechanical tests of the soil and, based on the obtained results, make calculations related to stability analyses. The results obtained in this way are used for dimensioning the slope of exploitation slopes (excavation). Landslides occur when the ultimate shear strength is reached, and therefore, the adequate definition of shear strength parameters is one of the essential prerequisites for successfully solving the stability problem. Unlike earlier tests in Serbia, when the residual shear strength parameters were determined based on the usual conventional methods (direct shear apparatus, triaxial apparatus), this time, in addition to the direct shear apparatus, a ring shear apparatus was also chosen for testing. The paper shows the method of determining the residual shear strength parameters of high plasticity gray clays and siltstones of roof sediments from open pit mine Drmno, using direct and ring shear apparatus. The results show that the residual angle of internal friction for gray clays obtained with the ring shear apparatus is 9.9–10.8°, and for the siltstone, it is 11.8–12.9°, both of which are lower than the values obtained with the direct shear apparatus. In addition, correlations between the residual parameters of soil shear resistance and some physical indicators (plasticity index, clay content) are provided, showing high correlation coefficients. The proposed correlations should be used only when time and financial constraints prevent the execution of actual tests to determine residual shear strength, as concrete experimental procedures provide a much more reliable assessment of the residual strength properties of the soil.

Significant direction for the innovation and development of new machine tool is a developing a hybrid kinematic machine (HKM) which have the respective advantages of serial and parallel mechanism. This paper considers the developed domestic configurations of HKM. The paper presents the developed original HKM configurations in University of Belgrade Faculty of Mechanical Engineering and Faculty of Technical Science University of Novi Sad.

The 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 used.

Introduction/purpose: All data exchanged over the Internet as well as other computer networks should be considered exposed to various types of security threats. In light of this, the transmission of voice over applications that do not use any type of crypto-protection allows anyone to discern the content of communication. Since voice transmission requires as little delay as possible, various protocols are used to enable crypto protected real-time communication. This paper presents one solution in a desktop application variant. Methods: The essence in voice exchange systems as well as in other systems where real-time communication is necessary is the establishment of a crypto-protected session which is a virtual secure channel for communication to which only the communicating parties have access. Voice sessions in the application are established with the SIP (Session Initiation Protocol) protocol. The sessions are further protected using the ZRTP (Zimmerman Real-time Transport Protocol) protocol. FusionPBX was used as the SIP server (registrar) for testing purpouses. The application is developed in C++ language using the Qt framework. Results: The final version of the application demostrates that ZRTP and SIP protocols are well suited for establishing crypto protected voice communications with low delay. Conclusion: This solution provides cryptographic functions for data secrecy and the management of cryptographic keys. Improving the solution with digital signatures and certificates will result in additional cryptographic functions: data integrity and personal identification. With this improvement, this solution will be able to withstand modern security threats with low delay.

Dripping rainfall simulators (DRS) for soil research generate water drops with different types of drippers, but metal tubes are most commonly used, often in the form of hypodermic needles. However, scientific papers using dripping rainfall simulators are often incomplete in terms of data on hypodermic needle characteristics, as well as data on drops produced by hypodermic needles under different water pressures. This study determines which drop sizes and dripping speeds are generated by various hypodermic needles at different water pressures. For the purpose of this study, a dripping rainfall simulator was designed and constructed for laboratory use. Water drops were generated with 11 different needles, ranging in size from 16 G to 32 G (tube gauge number), at different water pressures. Measured water drop sizes ranged from 1.42 to 3.69 mm at a dripping speed between 10 and 360 drops per minute and water head from 14 to over 1970 mm. Measured drop sizes, supplemented with data from previous studies, provided information on the relation between drop sizes and the size of the hypodermic needles. Van Boxel’s numerical model provided estimations of the fall velocity for different drop diameters and their kinetic energy for falling heights up to 11.5 m. The results of this research can be used to design dripping rainfall simulators for soil research.

The paper presents the programming and program verification of industrial robots that perform machining tasks. The paper considers the different methods for robot programming and the possibilities for configuring virtual robots for machining simulation and program verification for such tasks.

Due to the great expansion of woodworking, profile tools manufacturing has become current and in demand. In wood industry there are two large groups of tools: rotary and spindle milling cutters that can be profile or flat. The technology of making profile rotary milling cutters requires, apart from cutting, turning, milling, 5-axis grinding operation that is performed on a 5-axis CNC grinding machine with the A'OXYZC configuration.It is a machine of a very complex kinematics and high cost-price. The paper presents a new machine that has been built for 3+2-axis grinding - Profilator 100,used for industrial manufacturing of rotary and spindle profile milling cutters. The accuracy of measures and shapes of the profile cutters built on Profilator 100 is of a high level and in industrial exploitation the difference is not observed between the profile cutters built on 5-axis CNC grinding machines. Regarding technoeconomic cost-effectiveness, production costs of Profilator 100 are lower even by ten times compared to the cost-price of 5-axis CNC grinding machines of renowned world manufacturers such as Schneeberger and Volmer.

This paper describes the conversion of a virtual machine from different CAD/CAD environments and its configuring in the desired environment, which often arises as a need when you want to simulate the operation of a specific machine. In this case, two CAD/CAM environments are considered, namely Cimatron and Creo. The possibility of transfer the desired virtual machine from Cimatron CAD/CAM system and its converting to PTC Creo is considered, with an example of identical simulation in both environments. The transferred files of virtual machine are configured in the PTC Creo and STEP-NC Machine software environments. After configuring the virtual machine, the machine simulation was performed in the mentioned software environments.

This paper presents an approach for developing the programming and offline simulation systems for low-cost industrial robots in the MatLab/Simulink environment. The approach is presented in the example of a virtual model of a 4-axis robot with hybrid kinematics intended for manipulation tasks. The industrial robot with hybrid kinematics consists of the well-known 5R planar parallel mechanism to which two serial axes have been added. The programming system developed in a MatLab environment involves generating G-code programs based on given pick and place points. The virtual model included in the simulation system is configured in the Simulink environment based on the CAD model of the robot and its kinematic structure. The kinematic model and the inverse kinematic problem have to be included in the virtual model to realize the motion of the virtual robot. The system of programming and simulation has been verified through several examples that include object manipulation to perform various tasks.

The Covid 19 epidemic has reached unprecedented proportions and caused catastrophic consequences in all spheres of society. The effects of this epidemic have affected business organizations, namely companies in the Republic of Serbia as well. Considering that the infectious disease Covid 19 has the character of a public danger, taking emergency measures was expected. The potential threat to the life and health of employees launched certain requirements, which were necessary to meet in order to achieve safe working conditions. The paper is based on the analysis of security of employees in emergency circumstances caused by infectious disease Covid 19. The risks and threats of Covid 19 and the importance of applying prescribed protection measures in order to achieve an acceptable level of safety and health at work, as a significant segment of complex and dynamic corporate security.

This paper describes methodology for application of a rapid prototyping using subtractive, additive and formative technology based on STL files. Rapid prototyping technology includes using of a digital information chain CAD/CAM/CNC to a level which allows the successful realization of the physical models based on new technologies by adding, subtracting and molding material. The paper discusses about the usual technologies for rapid prototyping, for which a generalized methodology for their application has been proposed. The possibilities for program verification prior to the realization of the model were also shown. The methodology is verified on real examples of making selected parts. Used technologies are subtracting and adding material layers, layer by layer, and mold making (by adding material) for molding the silicone model.

The specific needs of customers set requirements like flexibility and custom-made products, as well as quick placement of products on the markets. Mass customization responds to these requirements and imposes new demands inside manufacturing systems such as optimization and virtualization of machining and measurement processes. A contribution in that direction is presented in this paper, pertaining to development and verification an on-machine measurement planning model. The aim of the verification is to visualize collision check between the measuring head placed in the tool holder and the workpiece on the machine tool working table. The virtual on-machine measurement was realized on the configured virtual machine tool LOLA HBG80 in the CAD environment. The measurement path is generated by a new planning methodology, then optimized using ants colony, programed and verified by simulations through few examples of standard forms of tolerance. The output of the simulation process is the G-code for real on-machine measurement for prismatic parts of medium and rough dimensional accuracy.

Land use and building regulation within protected natural areas in Serbia is specific in comparison to areas without this status. Since urban plans define the rules and conditions limited to urban settlements and locations of national priority (e.g. tourism resort in natural protected areas), other areas, including significant parts of protected natural areas, rely on spatial plans, which often contain elements of detailed urban planning (i.e. regulation and building rules). Preservation of ecologic and environmental functions is a priority in protected natural areas (particularly in zones of I and II level of protection), but they are also eligible for controlled development purposes in zone of III level of protection. Due to large distance from administrative centre and institutions responsible for building inspection, it is not rare case in Serbia that illegal building in protected areas makes them more exposed to illegal actions. Therefore, this paper focuses on the role of spatial plans in balancing between land use and building in protected natural areas on the one hand and nature protection on the other hand. In-depth analysis of chosen spatial plans, here is given a comprehensive review of building and land use postulates, regulations and different levels of protection applied in spatial planning. Starting from the Spatial Plan of the Republic of Serbia 2010-2020, analysis gives a major significance to four special purpose area spatial plans of different kind: Gornje Podunavlje Special Nature Reserve, Tisa River Multifunctional Ecological Corridor, Kopaonik National Park and Vlasina Landscape of Exceptional Features. Finally, there is shown diversity and systematisation of existing measures, and contribution to understanding of challenges and recommendations on future improvements of methodology in planning and implementation of plans in order to enhance balance between development and protection.

The paper presents one of the concepts of a reconfigurable desktop 5-axis machine that is operated using the PC Linux CNC system EMC2. For realization of control system, the necessaryis included kinematic model , which is embedded in the EMC2 control system. The paper presents configuring of the virtual machine tool that is first integrated with the programming system, and then with the control system. Verification of the control and programming system is achieved using configured virtual machine which is running on the basis of the given program and plotting the programmed tool path.

Industrial robots are a proper alternative to 5-axis machine tools for multi-axis milling of parts from softer materials and lower tolerances. For these reasons, researchers develop software solutions to bring programming of machining robots closer to programming of machine tools. The paper presents the results of kinematic modeling of vertical articulated industrial robots to emulate 5-axis horizontal machine tools. The solution to the inverse kinematics problem was the basis for the analysis of the machining robot workspace. Starting from equations of direct and inverse kinematics the control and programming system in G-code was developed, based on EMC2 software system. Developed control and programming system enables use of the available CAD/CAM systems for programming 5-axis machine tools, i.e. it is directly applicable by programmers and operators experienced in CNC technologies and G-code programming. Verification of kinematic modeling and developed control and programming system was carried out by machining experiments on an available domestic 6-axis robot LOLA 50.

The evolution of different urban public transport modes is pushed by different user demand levels, urban environment patterns and even natural constraints and barriers. The desire to overcome geographical and topographical barriers such as mountains, valleys and water, which cannot be efficiently served by conventional transport modes (bus, trolleybus, tram, metro, etc.), led to the introduction of aerial tramways or aerial cable-cars. Aerial tramway system is defined as the transportation technology that moves people in motor-less, engine-less vehicles that are propelled by a steel cable. Although technical, technological and economic aspects of aerial tramway introduction are well documented, very little effort has been made in defining the optimal market for this transport mode. The aim of this paper is to define potential aerial tramway users’ attitudes, opinions and requirements. Specific methodology is defined taking into account the differences and particularities of each user group: citizens, domestic and foreign visitors. Methodology is applied in Belgrade, Serbia.

A new programming method of CNC Machine tools, which is developing as an alternative to G code, is AP238 protocol or STEP-NC, according to ISO 10303 standard. In this paper, a comparation between classical (G code) and new way of programming (STEP-NC ) is given. A structure of equipment needed for new programming method, program structure and current scenario for implementation of STEP-NC are shown. Verification of the above scenarios using the STEP-NC, is realized through three examples.

Energy efficiency has become an integral part of the projects by adoption of laws and regulations on energy efficiency in 2011. This paper presents energy rehabilitation of the primary school building 'Dobrila Stambolic' in Svrljig. Energy restoration of this building, in addition to replacement of the roof cladding and roof constructions, included the installation of thermal insulation on all facade walls of the building, replacement of windows and heating system. By applying the suggested refurbishments the building energy class rating transferred from F to D which is two classes improvement.

This paper presents modeling and analysis of a 2-axis reconfigurable parallel mechanism. In this paper, generalized model for solving of inverse and direct kinematic problems is presented. Generalized equations that represent the solution of the kinematic problems of parallel kinematic mechanism applicable to any configuration of 2-axis reconfigurable parallel mechanism are derived. Some of characteristic configurations of 2-axis parallel mechanism are shown as examples. For the selected configurations the workspaces are determined and the possible singular positions of these configurations are analized.

This paper presents a desktop reconfigurable machine tool with hybrid kinematics for four types machine tools, with a description of the applied mechanism and established a modular system for their configuring. The postprocessor for five-axis machining presented in this paper is applied to the kinematic structures with table-tilting with two rotations (B,C). Also are shown solving the position of actuators p1 and p2 when the machine works with hybrid kinematics. Verification of postprocessor is realized on virtual prototype in CAD/CAM environment and experimentally on an available 3-axis machine tool. Experimental results confirmed the configured postprocessor which can be used for programming machine tools.

This paper presents a methodology for establishing off-line programming system with toolpath verification and simulation including visualization of the machining process, fixture orientation and machine movements. This methodology is described using IDEF0 diagrams and is elaborated by using PTC Creo CAD/CAM system. This paper describes modeled detailed virtual prototype of WEDM machine Ewis, with all kinematic relationships between moving components being defined, with the aim to include virtual machine model in machine simulation. Off-line programming allows immediate execution on the machine of multiple verification programs after verification. Therefore, the off-line programming is verified using the real example and its program verification and execution.

The state of development and application of compressed natural gas (CNG) buses in Serbia is presented, together with a review of their number in some European countries and cities. After several years of operation of these buses in the largest fleets in Serbia (Belgrade and Novi Sad), an analysis of their economic benefits and ecological characteristics has been carried out. Special attention is paid to the operational costs and possible savings achievable by CNG buses compared to diesel buses. Ecological characteristics of these buses are presented through the measurements of exhaust emissions on one type of these buses and through presentation and analysis of data from the literature on emissions of the buses of identical or similar engines. The preformed investigations show that application of CNG buses brings significant savings as regards total costs during their operational lifecycle compared to diesel buses. On the other hand, CNG buses have a significant ecological potential as regards fulfilling stringent requirements for exhaust emissions standards.

The model of a rigid body and heavy foot joined by the revolute joint in the constant gravitational field is described. The rigid body moves in the vertical plane, whereas the heavy foot lies on the flat, very rough horizontal support. Conditions for the dynamic balance of this system are mathematically expressed by using the ZMP method. It is shown that they determine an area in the phase space in which the state of the system should be in order that its dynamic balance is kept. It is also shown by appropriate simulations of motion of the system in the dynamic balance that these conditions are not sufficient for the system to keep its upright posture, but are in connection with its controllability. It is briefly discussed what are the necessary conditions for this system in dynamic balance to keep its upright posture.

This paper presents the development of mini laboratory and educational desktop 3 axis milling machine with parallel kinematic. Functional requirements and concept of this machine were adopted. Description of the applied parallel mechanism is shown in this paper. The presented methodology was used to configure mini laboratory and educational desktop 3 axis milling machine with parallel kinematic using IDEF0 diagrams, with detailed development activities who are made on the implementation of the prototype machine. Verification of the concept of virtual prototype is described using simulation on virtual machine in the CAD/CAM environment. The paper presents some of the most characteristic details in the implementation of the prototype, as well as his development testing.

Rad se bavi definisanjem tipologije lounge potencijala otvorenih prostora, koja se zasniva na slabim kriterijumima, da bi kao takva mogla biti primjenjiva u početnim fazama stvaralačkog procesa. Radi se jednoj vrsti subjektivne tipologije, različite od uobičajenih tipoloških istraživanja. Lounge podrazumijeva subjektivni osjećaj opuštanja koji nastaje na relacijama tijelo – okruženje. Fokus je na formiranju okvira, iz kog je ličnu percepciju potencijala okruženja moguće analizirati i usmjeriti ka lounge koncepcijama.

Many groundwater sources face a reduction in the exploitation capacity due to well aging. The well changes its performance over time, whether in operation or out of work. The well aging is influenced by many factors. Consequently, economic, business and social problems arise. Well regeneration has shown the best effects in practice to address these issues. In the area of Kladovski Ključ on the banks of the Danube, a drainage system of wells is used to defend against high water levels. During the inspection of the wells, the products that affect the aging of the well were determined, and the regeneration of the wells was conducted using the chemical-hydraulic method. The paper presents the procedures of well regeneration and the obtained positive effects of the applied method seen through the achieved results.

The paper presents the technology of making brazed shaper milling cutters and with special reference to 5-axis grinding process (making of profile blades) on CNC grinding machine tool. Based on the analysis of the kinematics of the 5-axis grinding process, a new concept of profile milling tool production by a 3+2 axis grinding process on horizontal milling center was established. By Applying new concept, one tooth of profile tool was machined by grinding process. By obtained results, new approach for manufacturing of profile milling tools was verified.

The paper presents the configuring of a virtual prototype BiSCARA robot generated on the basis of a fully developed kinematic model of the robot. The virtual CAD model developed in this way will enable its implementation in the Python graphical environment as an integral part of the open architecture control system developed on the basis of the presented kinematic model. The developed kinematic model included solving the inverse and direct kinematic problem, determining the Jacobian matrix and workspace analysis. Verification of the kinematic model, i.e. the configured virtual prototype of the robot, was performed by simulations of the end-effector tip movement according to the given program in a CAD / CAM environment.

This paper describes configuring the virtual horizontal machining center LOLA HBG80 within the programming and verification system and the open architecture control system. The horizontal machining center LOLA HBG 80 is represented by an equivalent virtual machine in a CAD/CAM environment (PTC Creo and Catia), STEP-NC Machine environment, and the control system. Virtual simulation is essential for machining, and the developed virtual machines are used for program verification and monitoring of the machining process. The virtual machine in the programming system allows the verification of the program before sending it to the real machine and includes verification of the tool path (CLF-Cutter Location File) and G-code. The paper also discusses the possibility of applying a new programming method known as STEP-NC and preparing an adequate environment that includes a virtual machine. The virtual machine in the control system represents the last level for the final program verification and the process monitoring system.

The paper shows the configuration of a new educational machine based on hybrid kinematics mechanism. The concept of a three-axis O-X hybrid mechanism is described, consisting of a single serial translational axis and a two-axis parallel mechanism that can operate in two variants, with extended form O and crossed form X-joints of the parallel mechanism. The virtual prototype of the machine was configured in a CAD/CAM environment, where simulations of the mechanism's operation were performed. A programming system for machine has been prepared that also enables program verification. An open architecture control system based on the LinuxCNC platform has been configured for control of the machine. The trial work of the machine was performed in order to verify the realized prototype and control.

The paper shows the development of a 3-axis CNC machine tool for rapid prototyping by subtracting materials, with two translational and one rotating axis, whose control is based on the LinuxCNC system, with an integrated virtual machine as a digital twin. The concepts of machines with one rotary axis were analyzed and the concept of a machine for realization was adopted, which is completely configured in a CAD/CAM environment. For successful verification of the programming system, a virtual machine has been configured in the CAD/CAM system, as well as in Vericut. The final validation of the machine design was achieved by its trial work on characteristic examples.

The paper presents the concepts of a reconfigurable 2 axis parallel kinematic machine that is controled using the PC Linux CNC system EMC2. In this paper given the methodology for configuring a virtual machine tool that integrates with the control system and which is also reconfigurable. Verification of the methodology was achieved by plotting the programmed contour test, on various types and subvariants of the machine, on configured virtual and real machines.

Soil erosion is a global problem that negatively affects the quality of the environment, the availability of natural resources, as well as the safety of inhabitants. Soil erosion threatens the functioning of urban areas, which was the reason for choosing the territory of the Master Plan of Belgrade (Serbia) as the research area. The calculation of soil erosion loss was analyzed using the G2 erosion model. The model belongs to a group of empirical models and is based on the synthesis of the equation from the Revised Universal Soil Loss Equation (RUSLE) and the Erosion Potential Method (EPM). The estimation of soil degradation was analyzed in two time periods (2001 and 2019), which represent the time boundaries of the management of the Master Plan of Belgrade. The novel approach used in this research is based on using the land cover inventory as a dynamic indicator of the urbanization process. Land cover was identified using remote sensing, machine learning techniques, and the random forest algorithm applied to multispectral satellite images of the Landsat mission in combination with spectral indices. Climatic parameters were analyzed on the basis of data from meteorological stations (first scenario, i.e., 2001), as well as on simulations of changes based on climate scenario RCP8.5 (representative concentration pathways) concerning the current condition of the land cover (second scenario). A comparative analysis of the two time periods identified a slight reduction in total soil loss. For the first period, the average soil loss value is 4.11 t·ha−1·y−1. The analysis of the second period revealed an average value of 3.63 t·ha−1·y−1. However, the increase in non-porous surfaces has led to a change in the focus of soil degradation. Increased average soil loss as one of the catalysts of torrential flood frequencies registered on natural and semi-natural areas were 43.29% and 16.14%, respectively. These results are a significant contribution to the study of soil erosion in urban conditions under the impact of climate change.

U radu su realizovana istraživanja materijala neophodnog za održavanje zaštitnih balističkih prsluka. Predloženo je novo konstrukciono rešenje sa savremenim materijalom za izradu balističkih uložaka. U radu su prikazani rezultati laboratorijskih balističkih ispitivanja uložaka sa novim materijalom. Na osnovu rezultata ispitivanja zaključuje se da predloženo konstrukciono rešenje za izradu balističkih uložaka u potpunosti ispunjava zahteve aktuelnog standarda. / The work presents research of the materials necessary for the maintenance of protective ballistic vests. In this paper is proposed a new construction design with modern materials for ballistic inserts producing. This paper also presents the results of laboratory tests of ballistic cartridges with new materials. Based on the test results, it can be concluded, the proposed technical solution for making ballistic inserts adequately meets current standards.

Assuming that the theory for differential geometry of curve is correct, this paper introduces a spheres kinematical chain of changeable radii positioned in such a fashion that the centre of the next sphere is firmly attached to the previous one within the chain. The kinematical chain consists of the base sphere and the rest of the chain which is inside the base sphere. The paper discusses the undisturbed and disturbed motion of the base sphere. The gravitational acceleration is interpreted as equivalent central acceleration during undisturbed rotation of the base sphere. The disturbed motion with respect to the undisturbed motion is described by increments of corresponding kinematical quantities. The relationship with the existing laws for translational motion in the classical mechanics is also established. And finally, a simple experiment for verification of the exposed theory is proposed in this paper.

The application of industrial robots for machining is currently limited to tasks with low precision demands due to the low stiffness of industrial robots as compared to machine tools. This paper analytically describes an experiment-based compliance identification and analysis method for a 5- axis vertical articulated machining robot. An expansion of the conventional method for the calculation of the robot’s Cartesian space compliance that takes into consideration joint compliances and the Jacobian matrix is used. The analytical analysis considers the effects of the individual joint compliances on the resulting Cartesian space compliance. Experimentally, the Cartesian space compliance is obtained by direct measurement of the absolute displacements induced by static forces along 3-Cartesian directions at the tool tip from which the joint compliances are identified.

To evaluate the vibration serviceability of footbridge structures most structural engineers use pedestrian force models that are defined for walking on rigid surfaces. This approach is no longer applicable for slender, light-weight and low-frequency structures that are prone to perceptible vibrations under walking excitation. To overcome this issue, it is necessary to understand the pedestrian walking locomotion and how the locomotion process interacts with the vibrating structure. This paper compares three approaches for modelling pedestrian walking over lively structures, and it critically evaluates their suitability for modelling the feedback mechanism between the structure and the pedestrian. The models are evaluated with respect to their capability to reproduce human-like motion as well as to replicate the vibration patterns observed on lively bridges. It has been shown that models used in biomechanics are good candidates for applications in the structural engineering context.

Within Electric Power Utility of Serbia 1991, a thermal power plant 'Kostolac B', power 2 × 350 MW, started. Based on the examination of steam boiler pipe system, it is confirmed that it is in a 'bad' shape. Its most jeopardized parts are evaporating heating surfaces. Considering that there are areas within the evaporator that suffered more damage, wherefore the steam boiler is out of production, it is necessary to settle the reasons for those damages. In order to locate the jeopardized areas of the evaporator, we carried out a detailed hydraulic calculation. A thermal calculation of steam boiler was also carried out, considering that the evaporator is also located in the convective heating surfaces part. By settling the most jeopardized evaporator locations - a horizontal part of support tubes, it was enabled to make certain reconstructions during the capital repair, in regard of changing their inclination angle, which would provide safer work of the evaporator, and steam boiler as a whole.

This paper presents recent, numerical and experimental, developments in modelling dynamic loading generated by humans. As modern structures with exposure to human-induced loading, such as footbridges, building floors and grandstands, are becoming ever lighter and more slender, they are increasingly susceptible to vibration under human-induced dynamic excitation, such as walking, jumping, running and bobbing, and their vibration serviceability assessment is often a deciding factor in the design process. While simplified modelling of the human using a harmonic force was sufficient for assessment of vibration performance of more robust structures a few decades ago, the higher fidelity models are required in the contemporary design. These models are expected not only to describe both temporal and spectral features of the force signal more accurately, but also to capture the influence, psychological and physiological, of human-structure and human-human interaction mechanisms on the human kinematics, and consequently on the force generated and the resulting vibration response. Significant advances have been made in both the research studies and design guidance. This paper reports the key developments and identifies the scope for further research.