Table of Contents

  • MACHINES

    • Technological process and design features of vibrating seed dryers

      pg(s) 111-113

      Drying of materials is a complex technological process used in various industries and is often one of the main stages of production. This process, in particular for bulk materials, depends on humidity, particle size, hydrodynamic conditions of the particles flowing through the drying agent and environmental parameters. Grain dryers expose grain to harsher conditions than natural drying, which can potentially lead to a deterioration in grain quality. The combination of these factors determines the nature of the entire process. In agricultural production, the drying stage is one of the most important for grain preservation. Currently, the convective drying method is widely used for this process. However, along with its advantages, this method also has a number of significant disadvantages, one of the most important of which is its high energy consumption. In this regard, scientific research is being intensively conducted to develop ways and methods to reduce the energy intensity of the convective drying method. The effects of vibration on raw materials are being rapidly introduced in various industries. The use of vibration technologies during drying intensifies the process of processing grain raw materials due to the rapid renewal of its surface in contact with the drying agent. Fast and efficient drying with vibration technology reduces moisture content and the risk of fungi and mold in the grain. The construction of the dryer using vibration technology helps to avoid overheating of the grain, providing optimal temperature conditions, which contributes to the preservation of nutrients and other useful properties of bulk agricultural materials.

    • Device and technology for the production of foam granules of “breathable” composite material based on heat-treated rice husks

      pg(s) 114-117

      An innovative device and a cost-effective and environmentally friendly technology have been developed to produce porous composite materials by using two types of waste raw materials: residual biomass from agricultural production and municipal waste. Heattreated rice husk and ground waste glass were used as main components. The technological approach presented here allows for the preparation of “breathable” porous materials with the predominant presence of open pores and increased specific surface area. A promising possibility for the application of the developed materials is their use in bulk or in the preparation of various composite building elements based on inorganic binders. Recipes and an adequate technological regime have been developed taking into account the design characteristics of the production facility, the specificity of the waste raw materials used and the intended target performance of the products.

  • TECHNOLOGIES

    • Behavior of steel, Al and Mg alloys when thermal drilling

      pg(s) 118-121

      The article deals with determinatin the optimum parameters for thermal drilling of selected Al, Mg and steel alloys to be subsequently used for joining with thermoplastic matrix composites reinforced with bidirectional continuous fibers. The optimum thermal drilling parameters will be considered to be those which produce a bushing of sufficient length and thickness to penetrate the composite material to a thickness of 1.5 mm.

    • Analisis of the properties of wire ropes after long period of exploitation

      pg(s) 122-126

      Steel wire rope was breaked in exploratory conditions i.e. during hoisting the load. The requirement of the purchaser of the investigations was to find a reason which caused breaking the steel rope. In other words to check fitness for purpose of the used steel wire rope. Because of that all necessary investigations to solve this problem were performed. As first, quality of delivered rope was checked. More concretely it was checked chemical composition of the base material (steel strands and wires). Besides, quality of the base material i.e. presence of non-metallic inclusions, microstructure, segregation and decarburation of the rope wires was done. This investigation showed that base material is high carbon steel. Its quality fulfill necessary requirement. Therefore, the next step was to make failure analysis of the rope after long period of exploitation. These investigations contain visual inspection of the rope, metallographic investigations, fractographic analysis and tensile test.
      Visual inspection was performed according ISO 4309 and ASME B30.30. Standards [1-3]. This inspection was performed to all segments of the rope. To perform visual inspection segments were unwinded and separately tested. It was found that the most serious damaging was detected near the breaking point of the rope.
      Performed investigations clear confirmed that wear of the rope is the most often detected type of failure. Besides corrosion of the rope was detected at many locations too. Metallographic investigation detected the wear damage too. Scaning electron microscope (SEM) confirmed that shear and fatigue are the most often found types of fracture in the rope wires.
      It was concluded from the investigation to too that lubrication of the rope is different at different locations. It means that at some position there is no lubrication.
      It is obvious that defects (failures) which caused breaking of the rope appeared in the rope during exploitation.
      Metallographic investigations of the wires and visual control of the ropes segments and strands confirmed that all defects in the ropes are results of improper installation, manipulation and handling of the rope.
      Nominal value of the load, which can be hoisted by steel rope, became lower during exploitation. More concretely remained load, which can be hoisted, is in relationship 5:1 with nominal load [4-6]. So if higher load was hoisted, the rope will be breaked as it happened in our case.

    • Designing the spinal column of a quadruped robot by using additive manufacturing: A comprehensive approach

      pg(s) 127-131

      In this study, we aim to realize a methodology for designing the spinal column of a quadruped robot employing additive manufacturing techniques. Additive manufacturing processes have gained widespread usage owing to their ability to swiftly develop prototypes for research and actualize production-grade components. Our research commenced with the acquisition of vertebral dimensions sourced from real animals such as cheetahs. These dimensions were pivotal inputs for conducting kinematic analyses of the animal’s locomotion cycle.
      Through meticulous kinematic analysis, it was delineated the various positions assumed by the spinal column throughout the locomotion cycle. Furthermore, we assessed the maximal force to which the spinal column could be subjected. This evaluation formed a robust foundation for exploring diverse modeling approaches to identify the optimal solutions. An innovative solution emerged through the utilization of a beam featuring a variable cross-section. This approach facilitated precise customization of the design to align with our specific requirements. To manufacture all requisite components for the spinal column, we employed a single 3D printer utilizing the Fused Deposition Modelling (FDM) technique with PLA material. To validate the computational methods, it was developed a sophisticated test bench. By juxtaposing theoretical predictions against tangible experimental data, it was affirmed the accuracy of the theoretical approach. This validation serves as a springboard for subsequent phases in the design and production processes of quadruped robots.

    • Utilization of waste chromium electrolyte by addition of Al2O3 nanoparticles to obtain thin chromium coatings

      pg(s) 132-135

      Chromium coatings were obtained from spent (waste) chromium electrolyte with the addition of nanosized aluminum oxide. The recovery of the waste chromium electrolyte is carried out by the activation of the chromium ions using the addition of Al2O3 nanoparticles. Electrochemically thin chromium films were deposited directly on S235 steel. The recovered chromium electrolyte has a concentration of nanoparticles of Al2O3 up to 10 g/l, which particles act as intensifiers of the electrochemical process. Analysis was performed with a “Polyvar Met” metallographic microscope and a Bruker D8 Advance powder X-ray diffractometer (XRD). The microstructure of the layer and the matrix were examined and the main phases were determined. SEM-EDS analysis of the chromium layer and the steel matrix was performed. The thickness of the obtained chrome coating with aluminum oxide nanoparticles was determined, which varies between 5 – 10μm.

  • MATERIALS

    • Comparison of 2D and 3D digital image correlation in determining of deformation distribution

      pg(s) 136-139

      Digital image correlation tests were performed during cold deformation on aluminum – magnesium alloy. The comparison of strain distribution obtained with 2D and 3D digital image correlation was analyzed and compared. The comparison of strain distribution in static tensile tests was performed with qualitative strain distribution and quantitative line analysis and strain-time relationship. The tests showed that there were no significant differences in the strain values and distributions obtained using the 2D and 3D digital image correlation when comparing the qualitative and quantitative results.

    • About the problems of low technological plasticity of steel 04H14Т3R1F used in the production of pipes for nuclear energy

      pg(s) 140-143

      The features of the chemical and phase composition, structure and transformations in boride inclusions in the steel 04H14Т3R1F, used for the manufacture of hexagonal pipe covers used during transportation to the place of regeneration and storage of spent fuel assemblies (FA) of nuclear power plants, have been studied. It has been established that steel 04H14Т3R1F contains two types of boride inclusions (Ti,Fe,Cr,V)2B with a shell of (Ti,Cr,V)2B and (Fe,Cr)2B, which have significant chemical heterogeneity. It is shown that in the process of hot deformation the phase and structural transformations occur: a change in the composition of borides due to the redistribution of elements, dynamic diffusion fragmentation and release of “satellite” particles, brittle destruction of borides, boride transformation. The behavior of boride inclusions and their influence on the mechanical properties of 04H14T3R1F steel at different plastic deformation temperatures was studied.