Josef Jancar

The formation of a rigid, tough interface based on a nacre-like structure in carbon fiber (CF) composites is a promising way to eliminate low delamination resistance. An effective method of coating CFs is electrophoretic deposition (EPD), which, in the case of dissimilar components like graphene oxide (GO) and polymeric glue, usually requires chemical bonding/strong interactions. In this work, we focus on chitin nanocrystals (ChNCs), leading to an excellent mechanical performance of artificial nacre, where favorable interactions and bonding with GO are controlled by degrees of deacetylation (5, 15, and 30%). We prepared coatings based on GO/ChNC adducts with 95/5, 90/10, 50/50, and 25/75 ratios using optimized EPD conditions (pH, concentration, voltage, and time). The prepared materials were characterized using FTIR, TEM, XPS, SEM, DLS, and XRD. SEM evaluation indicates the formation of a homogeneous interlayer, which has a fair potential for chemical bonding with the epoxy matrix. Short-beam testing of epoxy matrix composites indicates that the coating does not decrease stiffness and has a relatively low dependence on composition. Therefore, all coatings are promising for a detailed study of delamination resistance using laminate samples. Moreover, facile EPD from the water solution/suspension has a fair potential for industrial applications.

Process Analytical Technologies (PAT) often rely on real-time spectroscopy, allowing for fast-paced process control and monitoring. However, the data generated from real-time spectroscopy for long-running process systems can result in excessively large databases, which can be challenging to manage and may not necessarily lead to better process control. Therefore, it is crucial to reduce the amount of data generated by real-time spectroscopy while still retaining the essential information needed for process control. This work explores various data reduction techniques to address this issue. IndPenSim, a simulated spectroscopic probing dataset, was used as an oracle model to study the impact of data reduction techniques on the resulting process control identification. For analysis, the data pipeline consists of using principal component analysis (PCA) for visualization, followed by truncation and pre-processing (e.g. baseline corrections). Moreover, we have discussed the impact of data size reduction techniques (e.g. spectral data column selection, data binning, and region of interest (ROI), etc.) on the different chemometric models (e.g. PCA, PLS-DA, SIMCA, and KNN, etc.). Finally, the study examined the impact of data reduction on the control strategy for a realistic industrial fed-batch penicillin simulator. The multi-class classification performance was analyzed, and the results were interpreted to determine the best approach for controlling the process. Overall, the study provides valuable insights into data reduction techniques for real-time spectroscopy in PAT, which can improve the efficiency and accuracy of process control and monitoring.

The formation of a rigid tough interface based on a nacre-like structure in carbon fiber (CF) composites is a promising way to eliminate low delamination resistance. An effective method of coating CFs is electrophoretic deposition (EPD), which, in the case of dissimilar components like graphene oxide (GO) and polymeric glue, usually requires their chemical bonding/ strong interactions. In this work, we focus on chitin nanocrystals (ChNCs), leading to an excellent mechanical performance of artificial nacre, where favorable interactions and bonding with GO were controlled by degrees of deacetylation (5, 15 and 30 %). We have prepared coatings based on GO/ChNCs adducts with 95/5, 90/10,50/50 and 25/75 ratios using optimized EPD conditions (pH, concentration, voltage and time). The prepared materials were characterized using FTIR, TEM, XPS, SEM, DLS, and XRD. SEM evaluation indicates the formation of a homogeneous interlayer, which possesses a fair ability of chemical bonding with the epoxy matrix. Short beam testing of epoxy matrix composites indicates that coating does not decrease stiffness and its relatively low dependence on composition. Therefore, all coatings are promising for a detailed study of delamination resistance using laminate samples. Moreover, facile EPD from water solution/ suspension has a fair potential for industrial applications.

The hydrothermal method is a cost-effective and eco-friendly route for preparing various nanomaterials. It can use a capping agent, such as a polysaccharide, to govern and define the nanoparticle morphology. Elemental selenium nanostructures (spheres and rods) were synthesized and stabilized using a tailor-made carboxymethyl starch (CMS, degree of substitution = 0.3) under hydrothermal conditions. CMS is particularly convenient because it acts simultaneously as the capping and reducing agent, as verified by several analytical techniques, while the reaction relies entirely on green solvents. Furthermore, the effect of sodium selenite concentration, reaction time and temperature on the nanoparticle size, morphology, microstructure and chemical composition was investigated to identify the ideal synthesis conditions. A pilot experiment demonstrated the feasibility of implementing the synthesized nanoparticles into vat photopolymerization three-dimensional-printed hydrogel carriers based on 2-hydroxyethyl methacrylate (HEMA). When submersed into the water, the subsequent particle release was confirmed by dynamic light scattering (DLS), promising great potential for use in bio-three-dimensional printing and other biomedical applications.

There is a pressing need for advanced fertilizer application technologies that enhance crop yields, maintain soil health and reduce the environmental impact from agriculture. Here, we report on the optimization of nitrogen release profiles of urea‐loaded polysaccharide (starch) superabsorbent carriers, employing analytical techniques including UV–VIS, FTIR, EDX, SEM and GC‐FID for structural and phospholipid fatty acids PLFA analyses. We fitted existing kinetic models to the uptake and release profiles, providing a link between nitrogen release kinetics and carrier structural variables. The inclusion of zeolite microparticles in the starch‐based carriers accelerated the rate of nitrogen release and increasing the maximum amount released. Field tests of the technology on maize crops demonstrated improved plant parameters and enhanced the soil microbial population. These findings highlight the promise of urea‐loaded natural superabsorbent carriers as a sustainable alternative to core‐shell CRF fertilizers and urease inhibitors.

Auxetic metamaterials possess unnatural properties, such as a negative Poisson’s ratio, which offers interesting features when combined with traditional materials. This paper describes the deformation behavior of a gel consisting of spherical auxetic inclusions when embedded in a conventional matrix. The auxetic inclusions and conventional matrix were modeled as spherical objects with a controlled pore shape. The auxetic particle had a reentrant honeycomb, and the conventional phase contained honeycomb-shaped pores. The deformation behavior was simulated using various existing models based on continuum mechanics. For the continuum mechanics models—the simplest of which are the Mori–Tanaka theory and self-consistent field mechanics models—the auxetic particle was homogenized as a solid element with Young’s modulus and Poisson’s ratio and compared with the common composite gel filled with rigid spheres. The finite element analysis simulations using these models were performed for two cases: (1) a detailed model of one particle and its surroundings in which the structure included the design of both the reentrant and conventional honeycombs; and (2) a multiparticle face-centered cubic lattice where both the classic matrix and auxetic particle were homogenized. Our results suggest that auxetic inclusion-filled gels provide an unsurpassed balance of low density and enhanced stiffness.