Szymon Bajda

The organic compounds 2-aminopyrimidine (AP) and 4-aminobenzoic acid (PABA) were selected for the synthesis of a compound by establishing the phase diagram and adopting the solid-state synthesis method. The phase diagram analysis suggested the formation of a novel intermolecular compound (IMC) at a 1:1 stoichiometric ratio of AP and PABA, along with two eutectics at 0.25 and 0.90 mole fractions of AP. FTIR and NMR spectroscopy were used for the structure elucidation of the intermolecular compound. The powder X-ray diffraction analysis revealed the novel nature of IMC (APPABA) and the mechanical mixture nature of eutectics. The sharp and single peak of the DSC curve suggested the melting and pure nature of the synthesized IMC. Various thermodynamic parameters of IMC and eutectics were studied. A single crystal of the IMC was grown from solution and its single-crystal X-ray diffraction analysis revealed that it crystallized in a monoclinic system with the P21/n space group. Hirshfeld surface analysis further validated the weak non-covalent interactions summarized through the single-crystal X-ray analysis. Studies on the IMC were thoroughly conducted to evaluate its antibacterial activity with reference to antibiotics, and it showed significant positive responses against various pathogenic microbial isolates (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella aerogenes, and Shigella boydii) and non-pathogenic microbial isolates (Enterobacter cloacae, Pseudomonas azotoformans, and Burkholderia paludis). It was also found effective against methicillin-resistant bacterial strains viz. Staphylococcus aureus MRSA.

The organic compounds, 2-aminopyrimidine (AP) and 4-aminobenzoic acid (PABA), are selected for the synthesis of a compound by establishing the phase diagram adopting the solid-state synthesis method. Phase diagram study infers the formation of a novel intermolecular compound (IMC) at 1:1 stoichiometric ratio of AP and PABA along with two eutectics at 0.25 and 0.90 mole fractions of AP. The FTIR and NMR spectroscopy are studied for structure elucidation of intermolecular compound. Powder X-ray diffraction study reveals the novel nature of IMC (APPABA) and the mechanical mixture nature of eutectics. Sharp and single peak of the DSC curve suggests the melting and pure nature of the synthesised IMC. Various thermodynamic parameters of IMC and eutectics have been studied. The single crystal of IMC has grown from solution and its single crystal X-ray diffraction analysis reveals that IMC has crystallised in a monoclinic having P21/n space group. Hirshfeld surface analysis further validated the weak non-covalent interactions summarized through single crystal X-ray study. Studies on IMC thoroughly have been done for its antibacterial activity and it has shown significant positive responses against various pathogenic microbial isolates (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella aeruginosa, Shigella boydii) and non-pathogenic microbial isolates (Enterobacter cloacae, Pseudomonas azotoformans). It was also found effective against methicillin-resistant bacterial strains viz. Staphylococcus aureus MRSA. The biodegradable IMC is an effective functional material with its future applicability as an antibacterial agent extending up to drug-resistant bacterial strains.

The development of various machines and equipment containing parts or assemblies made of hyperelastic materials (e.g., rubber, silicone) is difficult because of the intricacies involved in the description of their mechanical properties. This is especially seen in calculations using simulation...

Additive manufacturing (AM) technologies have been gaining popularity in recent years due to patent releases – and in effect – better accessibility of the technology. One of the most popular AM technologies is fused deposition modeling (FDM), which is used to manufacture products out of thermoplastic polymers in a layer-by-layer manner. Due to the specificity of the method, parts manufactured in this manner tend to have non-isotropic properties. One of the factors influencing the part’s mechanical behavior and quality is the thermoplastic material’s bonding mechanism correlated with the processing temperature, as well as thermal shrinkage during processing. In this research, the authors verified the suitability of finite element method (FEM) analysis for determining PET-G thermal evolution during the process, by creating a layer transient heat transfer model, and comparing the obtained modelling results with ones registered during a real-time process recorded with a FLIR T1020 thermal imaging camera. Our model is a valuable resource for providing thermal conditions in existing numerical models that connect heat transfer, mesostructure and AM product strength, especially when experimental data is lacking. The FE model presented reached a maximum sample-specific error of 11.3%, while the arithmetic mean percentage error for all samples and layer heights is equal to 4.3%, which the authors consider satisfactory. Model-to-experiment error is partially caused by glass transition of the material, which can be observed on the experimental cooling rate curve after processing the temperature signal.

Titanium alloys, due to their exceptional mechanical properties and biocompatibility, are commonly used to produce medical implants nowadays. However, the presence of such elements as aluminium and vanadium can be harmful to human health. One of the possible solutions could be replacing the titanium alloys with ultrafine-grained commercially pure titanium (cpTi). The yield and also the ultimate strength of cpTi can exceed 1000 MPa. One of the most promising methods in manufacturing medical implants with improved biological fixation is laser cladding in which bioactive glass coatings are imposed on metallic substrates. The aim of this work is development of a 3D numerical model of the above mentioned additive manufacturing process. The obtained model is able to predict the stress-strain and temperature distributions during the processing. A sequentially coupled finite element (FE) model of laser cladding has been developed by applying element birth and death technique to calculate the transient temperature fields used in the stress analysis. The concentrated volumetric heat source from the laser beam moving along the metal surface has been represented by the Gaussian distribution in the radial and exponential decay in the depth direction. The developed FE based numerical model is capable to support the optimal design of such advanced multi-layered structural materials using the laser cladding technique.

The complex analysis of the interface behaviour has been performed during constrained compression testing of 316L steel plates as a way towards processing of the multilayered metallic materials. The approach is based on a combination of experiments under appropriate operating conditions and computer modelling based on finite element (FE) methodology for interpretation of the test results. Multilayered metallic structure was successfully obtained using the applied constrained compression testing technique. The specially designed die and compression specimens allowed for joining of the steel plates together even at room temperatures. The performed numerical analysis using the ABAQUS/Standard FE software revealed the strain and stress localisation areas within the multilayered structure among other features that are described in the paper. The results are in agreement with experimental observations.