Table of Contents


    • Structuring key partnerships in the field of critical infrastructure security systems

      pg(s) 53-56

      Joint scientific and applied research occupies its place as a major innovation process in the activities of scientific, educational and business organizations. The purpose of this approach is to gain access to external sources of technology (or other assets) and their integration into products and services to build security of critical infrastructure and strategic sites of national importance.
      Partnerships in the development of security systems can bring added value to partner organizations, allowing them to use a wider network of promising assets and markets and helping them gain trust and prestige in society.
      The presentation of a variant of structuring key partnerships in the development of security systems is the content of this p aper.


    • Development of predictive maintenance based on artificial intelligence methods

      pg(s) 57-60

      Artificial intelligence become more widespread in all manufacturing subjects. In manufacturing artificial intelligence deals with such tasks as quality control, robot navigation, computer vision, processes controlling, etc. The area of maintenance in machining is a great prospect for implementing artificial intelligence tools for analysis, prediction of monitored parameters, optimization, and improvement of the quality of the maintenance process. In particular, the article refers to predictive maintenance as a modern trend in mechanical engineering. In this article, a quick review of using methods of artificial intelligence and predictive analytics in maintenance and one p ractical implementation case of NAR network for time-series prediction was provided.

    • Development of menstrual panties within the framework of sustainability and creation of a start-up

      pg(s) 61-63

      Direct At the Technical University of Liberec, Faculty of Textiles, there was a cooperation between this state university and a small private company. The cooperation was created for the development of sustainable aids for menstrual periods. All development took place at the university, including the search for local production partners, and the private company financed the development. The output is a utility model owned by the university and the private company, and in addition the private company pays the license fee. Th e article describes in more detail this cooperation, as well as the development and the developed product, up to its actual commercialization.

    • Financial project for construction of a plant for the production of granules, panels and plates of foam glass and small and large composite elements

      pg(s) 64-70

      A financial project has been prepared for the construction of a plant equipped with a technological line for the production of foam glass products. It is planned to build a warehouse for raw materials, a sector for preparation of materials, various production workshops for the manufacturing of foamed granules and pieces, a continuous tape or block of foam glass, various composite materials (thermal insulation and color decorative panels, various small and large composite elements, etc.), repair section and two warehouses for finished products. Approximate calculations have been made for the necessary raw materials, technical equipment, electricity, personnel and other costs for the realization and operation of the plant.

    • Economic Comparison of the Two Proposed Wind Farms in Mamaj, Albania

      pg(s) 71-75

      The study addresses to an economic comparison of two proposed wind farms in the same area in Mamaj, Albania, respectively 10.8 MW and 12.6 MW. The 12.6 MW wind farm proposed is predicted to produce 34 GWh energy, with a capacity factor of 30.8%, while the 10.8 MW wind farm is predicted to produce 30.4 GWh, with a capacity factor of 32%. For the 12.6 MW wind farm since there is a higher installed power, is expected to produce more energy, but referring that they will be built in same area, the wake losses will indicate in overall efficiency of the wind farm. The wake losses calculated for the 10.8 MW wind farm are 0.98%, meantime for the 12.6 MW wind farm wake losses is calculated 2.58%, means that the overall efficiency of the 10.8 MW wind farms is higher. For the economic evaluation RETScreen Expert software is used. With a discount rate of 7%, the benefit-cost ratio is 2.9 and simple payback period 7.6 years for 10.8MW wind farm, and for the 12.6 MW the benefit-cost ratio is calculated 2.6, with a simple payback year of 8 years.


    • Friction stir welding of dissimilar materials based on aluminum alloys

      pg(s) 76-78

      The paper focuses on the application of friction stir welding (FSW) technology for welding of unequal materials based on aluminum alloys. Joints were made from AW 5083 and AW 6082 materials using FSW technology at different weld speed values. The joints were analyzed metallographically, the hardness of the materials was tested across the cross section of the joint and the strength of the joint was tested by destructive static tensile test. At the lowest weld speed, the materials were not perfectly mixed, there was a macroscopically visible gap at the joint location, which was reflected in the lack of joint strength. At the medium and highest weld speed values, a joint with mechanical properties comparable to those of the base material was formed. Metallographically, the bond between the materials was free of any internal defects.

    • Innovative method for repair of reinforced concrete water facilities by “wet” shotcreting

      pg(s) 79-82

      The report presents the different stages of development and implementation of two similar innovative technical solutions for repair and restoration of defected reinforced-concrete constructions of existing swimming pool and artificial lake using the methods of “wet” shotcreting. In the first case, the object of renovation is a seriously defected outdoor mineral pool of a prestigious hotel in the town of Hissarya. Given the significant leaks of water from the pool in the surrounding area over the years, a specialized technical inspection was initially conducted to determine the causes of defects in the main load-bearing monolithic steel-reinforced concrete construction – walls and bottom slab. An innovative technical solution has been proposed to restore the operational suitability of the pool, based on the possibility of using the existing load-bearing structure as external formwork for a new built-in load-bearing structure of the facility. The proposed solution envisages jointless thickening of the existing walls through additional reinforcement and concrete laying of new high-tech sprayed concrete. The bottom of the pool is being renovated by additional new layer of a hybrid fiber-reinforced jointless concrete slab and machine powerfloated of the finishing surface. A composition of high-tech concrete with the participation of an internal crystallization chemical admixture and shrinkage-compensating one is proposed. A similar solution has been applied for the repair and restoration of the walls and bottom of an artificial lake in West Park, Sofia. Implementation of the project creates a unique art vision of the lake, the rock garden and the surrounding park space. This pilot implementation creates objective preconditions for expanding the range of innovative concrete structural systems, which, in addition to specific functions, are also applicable as opportunities for aestheticizing the urban and park environment.

    • Comparison of different position controllers implemented with a Beckhoff controller and TwinCAT 3 software

      pg(s) 83-86

      Achieving the required dynamics and accuracy of movement of electromechanical linear axes is one of the basic tasks in the field of modern production machines and devices. In addition to a sufficiently powerful electric motor, e.g. electric servomotor, the appropriate controller and control concept also play a key role. As the top performance of the electromechanical axle controller is still a key feature of efficient and quality production, this topic is discussed in this paper.
      At the forefront of the paper are the development and implementation of various position controllers developed in the Beckhoff TwinCAT 3 environment. In addition to the classic PID controller already available in the Beckhoff software, a special PID controller has been developed in the Matlab / Simulink environment, as well as a Fuzzy controller and a Feedforward control strategy. For all mentioned types of controllers, the basic characteristics, design approach and parameterization of the controllers are presented. The efficiency of individual position controllers on an industrial-type electromechanical linear axis, driven by an electric servomotor, was tested experimentally and the results are compared.
      The efficiency of these closed loop controllers was also tested in terms of robustness and ability to adapt to changes in the control loop, where a different load of moving mass was used as a characteristic change in the control loop.

    • Application of submodeling in strength analysis of horizontal tank for storage of petroleum products

      pg(s) 87-90

      This paper shows the approach of submodeling in finite element analysis in process of designing the horizontal tank for storing petroleum products. Those kinds of tanks are made at exact standards or slightly altered by customers’ demands. Before the numerical analysis of the tank, the tank standards are described as well as numerical analysis. In the paper, the methods which will be used in obtaining solutions by finite element method were described. 3D finite elements have been used for numerical analysis. After getting the results of full tank model meshed with 3D tetrahedral final elements, the technique of submodeling has been used to achieve more accurate results in critical locations of the tank. In the final aspect, result analysis was conducted, where the results were confirmed so that the tank complies with the standard and meets all the criteria given to the designer.

    • Studing the temperature microclimate in beehives made out of defferent materials

      pg(s) 91-92

      The use of clay as a structural material has been known for centuries. The authors set the task of studying the applicability of clay as a constructive material in the production of beehives. The study aims to make a comparative analysis of temperature conditions in different types and identical in construction beehives by comparing the indicator for ceramic and wooden hives. For the purpose were used three 10-frame hives type “Dadan-Blat” – two ceramic (one made entirely of marl clay, and the other – with increased kaolin content, both ceramic tiles are with high cavity) and one wooden (pine). Measurements of the air temperature and the temperature inside the hives were made for one month. From the obtained results it is established that for the studied beehives, the ceramic hive with high kaolin content has the best thermal insulation properties.

    • Use of oriented strandboard in construction industry

      pg(s) 93-96

      In recent years, 3D printing has gradually appeared in people’s field of vision. The addition of wood in thermoplastics improve their some mechanical properties such as tensile and bending modulus without affecting its biodegradability. The decrease in the cost of filaments may enlarge the utilization of biodegradable filaments after the disposal in near future. Small-scale elements used in furniture production, such as connector fittings or fasteners for shelves, may give functional and structural properties without significant investment. 3D-printed connections are suitable when the the production complex shaped connectors and quick disassembly are required, to reduce the product’s weight and price