This study investigates the structure and composition of the zinc phosphate coating formed on the surface of nodular cast iron as well as the corrosion resistance of the electrophoretic paint applied to the conversion layers when nitrite-based and nitroguanidine accelerators are used. In the case of different accelerators, the structure of the zinc phosphate layer that forms when exposed to low, normal and high dosages was examined. This type of casting, in addition to steel casting, is commonly used in the production of agricultural vehicles due to its favorable mechanical properties. Although the majority of studies have summarized its application in the automotive industry by focusing on the phosphating of steel, galvanized steel and aluminum-based alloys, on complex vehicle assembly lines, cast iron is also used in phosphating processes that occur simultaneously. During our investigation into the use of different accelerators, a different crystal structure formed on the surface of the cast iron but did not affect the corrosion resistance of the electrophoretic painted samples.

The subject of this research is the development of a digital twin for the process of mixing the components of a gas mixture in the mixer of a mixture generator. The problem is motivated by the concept of digitalizing modern production and is considered in relation to the technology in question for generating a gas mixture of a given composition and homogeneity. A gas-dynamic model of an unsteady flow has been constructed and a numerical study carried out using the Ansys Fluent software. The Reduced Order Model was developed and used in the Ansys Twin Builder platform to build the digital twin.

The self-diffusion coefficient of water in aqueous solutions of alkali halides at different concentrations was studied using the polarizable BK3 model of water [1]. As ion potentials, initially the alkali halide force field fitted to this water potential by the solvation free energy, ion-water clusters as well as, for the purpose of crosschecking, to the ambient crystal energy and density was investigated. It was found that the strength of attraction between the central ion and the water molecules in the hydration shell is stronger than in reality, which manifests itself in the reduced mobility of water. For small ions, this discrepancy is small. By omitting the dipolar polarization of larger ions, the estimates could be improved. Similarly, increasing the size of the anions within reasonable limits also enhances the results but the structural breaking effect is insufficient. If the relative permittivity of water is smaller than that measured experimentally, typically ionic charges in non-polarizable water models can be decreased to recover the correct semi-macroscopic Coulomb energy. Since our polarizable water model reasonably estimates the relative permittivity, smaller ionic charges were used to quantify the differences in the strengths of ion-water attraction. Our estimates of self-diffusion in aqueous solutions by varying the concentration of ions are presented and discussed for LiCl, NaCl, NaBr, NaI, RbF and RbI.

Geopolymers are modern synthetic materials that have many beneficial characteristics, e.g. excellent mechanical properties, fire- and heat-resistance, minimal shrinkage and can be molded into shape. Given their aforementioned characteristics, geopolymers could be applicable as conditioning materials, e.g. to handle hazardous waste and radioactive materials. However, their long-term applicability needs to be investigated.The aim of this study is to investigate the mobility of Cs-137 radionuclides in embedding materials. Different geopolymeric matrices - namely kaolinite, bentonite, zeolites and red mud - were tested. The leach test was performed according to the ASTM C1308-08(2017) standard and the activity concentration of Cs-137 isotopes was measured by gamma spectrometry using a high-purity germanium (HPGe) semiconductor detector. According to our preliminary results, the matrices that resulted in the most significant immobilization effect were those in which bentonite, cement, fly ash and 8M NaOH were used, releasing approximately 10% of the cesium.

This paper discusses the challenges involved in producing high-quality alumina ceramics, particularly when it comes to achieving a suitable degree of surface roughness and high accuracy. Alumina ceramics are widely used in various applications due to their exceptional properties, including high strength, wear resistance and chemical stability. The alumina ceramic pistons with the desired properties and performance were produced from commercially available raw materials. To improve the densification and mechanical properties of the sintered ceramics, an organic binder was used. The use of a diamond abrasive slurry for polishing was also studied, which has proven to be particularly effective in achieving a high degree of surface finish. The study aims to produce alumina-based pistons with a low level of surface roughness as well as discusses the techniques and methods used to achieve this goal. The results of this paper include the porosity, mechanical properties and microstructure of the alumina ceramics produced in addition to the effectiveness of the techniques and methods applied.

The annealing effect of an alkali borate type glass below its softening point was investigated according to the Na2O-B2O3 binary system. The samples were doped by introducing different amounts of copper oxide (CuO). The properties of elaborate glasses before and after annealing were studied. X-ray diffraction (XRD) as well as optical and infrared spectroscopy were used in this study. The results obtained show that annealing, that is, a heat treatment process, affects the structure of this type of glass by redistributing its structural units and partially correcting any defects, thereby reinforcing the structure. It was noticed that the BO3 units were reformed while the number of BO4 ones decreased, leading to an increase in the coefficient of thermal expansion, a decrease in both the refractive index and optical dispersion, the weakening of mechanical properties as well as a reduction in thermal conductivity and electric permittivity.

The processing technology of steel structural elements of aircraft parts is especially important since, if improperly processed, this material can be subjected to weathering, causing corrosion. Furthermore, special attention is paid to the walls of holes used for bolting. Since holes can become stress concentrators, the paper proposes to strengthen them by implementing the SPD (surface plastic deformation) method. The article describes the simulation of the mandrelling process, which is more efficient and less traumatic. Therefore, changes in the walls of holes as a result of deformation are shown, which occur after the process of hole mandrelling.

The aim of our research was to design and construct a measuring device that can determine the rolling resistance coefficient (RRC) under laboratory conditions. The measuring device has a drum arrangement, and the RRC was measured on two different model surfaces. The deceleration method was used to investigate the dependence of RRC on compression force, velocity, and surface temperature on steel and rubber surfaces. The measured RRC values (0.010 – 0.025) were similar in magnitude to the values characteristic for asphalt-covered roads. By increasing the model road surface temperature up to T = 60 ◦C the RCC dropped by ~13% compared to the values at T = 22 ◦C

Biodegradable packaging materials are attracting more and more interest nowadays, the primary driving force of which is the generation of enormous amounts of plastic packaging waste. The aim of this study was to investigate the effect of two castor oil-based experimental additives on the properties of foils made from incompatible biodegradable polylactic acid (PLA) and native starch (10-50 wt%). Differential Scanning Calorimetry (DSC) measurements and tensile tests were used. It was found that increasing the starch content affected the crystallization of PLA in the blends. Furthermore, since the additives did not significantly change the glass transition temperatures, the additives did not affect the mobility of PLA chains. Regarding the tensile tests, the tensile strength of the 60:40 PLA:starch longitudinal sample could be increased by approximately 10 and 6 MPa at 25 and -25 °C, respectively, when additives were introduced.

In this study, a waterproof polyaspartic coating used for concrete structures was modified into an anti-corrosion coating system to prevent steel assets from corroding. A micaceous iron oxide barrier, a zinc phosphate corrosion inhibitor and a novel resin hardener were added to the polyaspartic coating. Its corrosion performance was assessed through immersion corrosion tests in 3.5% NaCl solutions at room temperature (RT) and 35 °C for 30 days. The surface finish of the steel samples was milled and blasted (SA 2.5). The coating was applied directly to the metal substrate. The average thickness of the coating was 220 ±10 µm. The experimental results confirmed the successful enhancement of the control coating on steel that was previously applied to concrete by adding a zinc phosphate corrosion inhibitor and micaceous iron oxide barrier. However, defects in the coating and rust on the substrate of the control coating were hindered by applying the developed coating.