Izabela Zgłobicka

Hemp-based mycelium composites are promising bio-based materials, but their heterogeneous structure may strongly affect mechanical performance and stability under water exposure. Six hot-pressed composites based on hemp hurds and chopped hemp straw, colonized with Pleurotus ostreatus or Ganoderma applanatum, were investigated. Depending on formulation, spent coffee grounds, thermoplastic or plasticized starch, and polymeric components introduced as granules, film flakes, or poly(ε-caprolactone) meshes were incorporated. Apparent density, water absorption, dimensional changes during immersion, compression, and three-point bending were evaluated. Mean apparent density ranged from 0.69 to 0.96 g × cm⁻³ and showed a positive specimen-level association with maximum compressive stress within the investigated plates (Spearman’s ρ = 0.845, n = 30). Because only one plate was manufactured per formulation, the observed formulation-specific property profiles represent exploratory observations within the investigated manufactured plates rather than population-level estimates of formulation effects or manufacturing reproducibility. The highest mean maximum compressive stress was 5.7 ± 1.2 MPa, whereas the highest mean maximum flexural stress and flexural modulus were 4.6 ± 2.1 MPa and 627 ± 285 MPa, respectively. Water uptake, dimensional swelling, and retention of measurable integrity followed different formulation-dependent trends; the greatest through-thickness swelling did not necessarily correspond to the fastest loss of cohesion. Overall, density, mechanical response, water uptake, dimensional deformation, and wet-state integrity were related but distinct descriptors of material performance, highlighting the need for multi-property optimization.

Plant-derived residues may provide locally available components for mushroom cultivation substrates, but their variable composition requires preliminary physicochemical characterization. The aim of this study was to evaluate the physicochemical parameters of selected plant-derived residues in terms of their suitability as substrate components for the cultivation of Pleurotus ostreatus. The primary raw materials used were: oak sawdust, birch sawdust, wheat straw, triticale straw, rapeseed straw, and hemp shives. In addition, spent coffee grounds and apple pomace were applied as supplements enriching the substrate. The tested materials were subjected to physicochemical analyses including the determination of pH value, nitrogen, phosphorus, potassium, magnesium, calcium, sodium, organic carbon, and heavy metal content. The lignocellulosic materials showed high C:N ratios (80–257), indicating the potential need for nitrogen supplementation. Spent coffee grounds had the highest nitrogen content (21.61 g·kg⁻¹ DM) and the lowest C:N ratio (25.96), while apple pomace showed the lowest pH (3.85). Wheat and triticale straw supplemented with spent coffee grounds were identified as promising candidates for further cultivation trials, supporting the valorization of plant-derived residues in line with circular economy principles. As the study was limited to preliminary physicochemical screening, lignocellulosic-fraction analysis, physical characterization, and cultivation trials are required before the technological suitability of the proposed mixtures can be confirmed.

The structural, processing, and mechanical response of a multiphase poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/poly(butylene adipate-co-terephthalate) (PBAT)/thermoplastic starch (TPS) matrix to two distinct glass fillers was investigated. Glass fibers and hollow glass spheres were incorporated by melt compounding and injection molding, while the unfilled blend served as the reference. Differential scanning calorimetry, X-ray diffraction, melt-flow-rate measurements, helium pycnometry, scanning electron microscopy with deep-learning-based segmentation, tensile, and Charpy impact tests were applied. At higher filler contents, the composite-level XRD-based crystallinity index decreased to approximately 47%, whereas the Scherrer-derived PHBV (110) coherent-domain size remained within approximately 21–24 nm. Preferred orientation, assessed independently from the PHBV reflection-intensity ratio, varied with filler type and content. Glass fibers progressively reduced melt flow and were associated with an increase in tensile modulus from 2.06 to 3.45 GPa and maximum tensile stress from 23.46 to 27.32 MPa at the highest investigated fiber content. Hollow glass spheres produced a non-monotonic melt-flow response, while the reduction in tensile performance at higher contents coincided with decreasing interparticle spacing and increasing specific external polymer–glass interfacial area. Within the analyzed SEM fields, no pronounced filler-rich clustering was evident. Notched specimens remained brittle, whereas unnotched specimens retained impact strength above 10 kJ × m⁻². Overall, the two filler geometries exhibited distinct relationships among apparent melt flowability, crystalline organization, quantitative microstructural descriptors, and mechanical response.

This work investigates the physicochemical characteristics of waste tire pyrolysis char (WTP-char) produced at 500 °C in an industrial-scale auger reactor. The study uniquely combines material profiling with environmental safety assessment, specifically targeting organic contaminants and polymer stabilizers, evaluating WTP-char’s potential for circular economy applications. The samples underwent comprehensive analysis, including GC-MS, TGA, SEM-EDS, TXRF, and BET surface area measurements. The results revealed a high volatile matter content (13 wt.%), attributed to the thermal inertia typical of industrial-scale units. The organic fraction was dominated by n-alkanes (48.3%) and a significant concentration (6.97%) of the stabilizer Tris(2,4-di-tert-butylphenyl) phosphate (bDtBPP), posing potential environmental risks due to its cytotoxicity. Polycyclic aromatic hydrocarbon (PAH) analysis showed a prevalence of high-molecular-weight (HMW) compounds (79.7%), indicating high chemical stability. Although the specific surface area was low (28.9 m²/g), suggesting the need for activation, the material exhibits potential as a low-cost semi-reinforcing filler or solid fuel. By moving beyond laboratory-scale experiments to real industrial production, this study establishes a practical framework for evaluating both the performance and environmental safety of waste tire pyrolysis char.

In this study, thermal deformation in non-planar, large-scale additive manufacturing (LSAM) was experimentally and numerically investigated. A Bézier-based non-planar build surface was fabricated by CNC machining, and a single layer of ABS was deposited using a hybrid LSAM system. Toolpaths with raster angles of 0° and 45° were generated for surface-conformal printing. Infrared thermography was employed to monitor the thermal history during deposition. A three-dimensional finite element model was developed to simulate transient heat transfer and thermally induced deformation. Experimental deformation was quantified by 3D scanning and compared with simulation results. The results show that the slope geometry strongly influences deformation direction: negative slopes promote contraction, whereas positive slopes lead to upward deflection. Maintaining the material temperature above the glass transition temperature significantly reduces skew deformation. The finite element method predictions demonstrate strong agreement with experimental measurements, with normalized root mean square errors (NRMSEs) of approximately 11% for thermal deformation and 10% for temperature history. The proposed framework enables prediction and mitigation of thermal warping in non-planar polymer additive manufacturing.

Diatom frustules exhibit highly organised silica architectures with submicron features, which are widely studied. Nowadays, scanning electron microscopy (SEM) is commonly used for studying their morphology. However, SEM provides a two‐dimensional projection that distorts the true size of three‐dimensional features. In addition, samples for SEM observations are usually prepared by removing organic parts and drying the remaining parts made of bio‐silica (so‐called frustule). Here, we combine high‐resolution SEM and liquid‐cell SEM imaging with confocal microscopy to construct a curvature‐aware correction model that accounts for the surface area distortion in SEM imaging caused by the in‐plane projection of three‐dimensional frustule geometry, demonstrated using Diploneis didyma frustules as a case study. The paper describes how automated image analysis enabled the detection of individual pores, the localisation of their centroids, and the calculation of curvature‐corrected surface areas. True diameters of the frustules are provided, and drying‐induced shrinkage of pores is obtained. Species length‐based normalisation of morphometric data reduced variability and allow to infer systematic dependence of pore sizes on position on frustules. The results establish a reliable framework for quantitative characterisation of diatom frustules and can be applied across disciplines requiring accurate morphometrics of biogenic silica structures. LAY DESCRIPTION : Curvature‐corrected SEM morphometrics, paired with hydrated/dehydrated imaging, offer a reliable quantitative framework for diatom frustule pore‐size assessment. Drying shrinks pores by ∼10%, so dry‐sample measurements should be corrected when targeting living/wet morphology. Curvature correction compensates SEM projection distortion, with uncorrected pores underestimated by ∼34% on average, enabling realistic edge‐to‐centre comparisons. The protocol is broadly transferable beyond Diploneis didyma with minor adjustments and supports applications in taxonomy, biomonitoring, and bioinspired design.

Transparent polymeric materials such as poly(methyl methacrylate) (PMMA), polycarbonate (PC), and polyethylene terephthalate (PET) are widely used as glass alternatives in algal bioreactors, where optical clarity and mechanical stability are crucial. However, their long-term use is limited by surface degradation processes. Photodegradation, hydrolysis, and biofilm accumulation can reduce light transmission in the 400–700 nm range essential for photosynthesis. This study examined the aging of PMMA, PC, and PET under bioreactor conditions. Samples were exposed for 70 days to illumination, culture medium, and aquatic environments. Changes in their optical transmittance, surface roughness, and wettability were analyzed. All polymers exhibited measurable surface degradation, characterized by an average 15% loss in transparency, significant increases in surface roughness, and reduced contact angles. PMMA demonstrated the highest optical stability, maintaining strong transmission in key blue and red spectral regions, while PET performed the worst, showing low initial clarity and the steepest decline. The most severe surface degradation occurred in areas exposed to the receding liquid interface, highlighting the need for targeted cleaning and/or a reduction in the size of the liquid–vapor transition zone. Overall, the results identify PMMA and recycled PMMA (PMMA_R) as durable, cost-effective materials for transparent bioreactor walls.

H-AlN promotes an O ₂ -first four-electron ORR pathway toward Li ₄ O ₂ formation, achieving low ORR/OER overpotentials of 0.178/0.104 V and total overpotential of 0.282 V, highlighting its potential as a bifunctional cathode catalyst for Li–O ₂ batteries.