Fakulta technologická

Biofilter and regenerative thermal oxidizer controls for olive oil mill volatile organic compounds in Crete

Wed, 01 Jan 2025 00:00:00 GMT

Biofilter and regenerative thermal oxidizer controls for olive oil mill volatile organic compounds in Crete Marková, Alžběta; Qiming, Sun; Artykova, Mavlyuda; Nabiyeva, Nozima; Avezov, Said; Tukhtasinov, Khalilillo Olive oil mills emit volatile organic compounds from malaxation, decantation, and storage, which affect local air quality and sensory nuisance in Mediterranean settlements. This article evaluates end-of-pipe controls based on biological filtration and regenerative thermal oxidation for medium-scale mills in Crete. The objective is to compare pollutant removal, energy demand, greenhouse gas emissions, and costs under realistic exhaust compositions and operating profiles. Using open operational statistics for 2012-2024 and mass-balance models, we simulate three configurations: biofilter, regenerative thermal oxidizer, and a hybrid system with biological filtration followed by a polishing oxidizer. Indicators include removal efficiency for total volatile organic compounds, odor abatement, specific energy use, carbon dioxide equivalent per thousand cubic metres treated, and levelized cost. Results show that biological filtration achieves high average removal with the lowest energy burden, while regenerative thermal oxidation guarantees peak compliance at higher costs; the hybrid configuration balances reliability and climate impact for operators.

CFD-based evaluation of 3D-printed muffler inserts: Impact of internal geometry on pressure drop and turbulent kinetic energy

Thu, 01 Jan 2026 00:00:00 GMT

CFD-based evaluation of 3D-printed muffler inserts: Impact of internal geometry on pressure drop and turbulent kinetic energy Zvoníček, Tomáš; Novák, Libor; Smolka, Petr

Characterization of elastomer durability: Insight into compression set and stress relaxation

Wed, 01 Jan 2025 00:00:00 GMT

Characterization of elastomer durability: Insight into compression set and stress relaxation Zádrapa, Petr; Mrkvičková, Simona; Macourek, Vilém This study investigates the thermal aging behaviour of EPDM rubber compounds cured with varying concentrations of peroxide. Mechanical properties such as hardness, tensile strength, elongation at break, compression set, and stress relaxation were evaluated before and after exposure to elevated temperatures. A key innovation of this research is the use of a newly developed testing apparatus for stress relaxation measurements, designed to enable discontinuous long-term testing under controlled deformation and environmental conditions. The device allowed monitoring of stress decay over time, providing deeper insight into the viscoelastic behaviour of rubber material during thermal exposure. Results showed that peroxide concentration significantly influences crosslink density and aging resistance, with optimal performance observed at intermediate peroxide levels. The findings highlight the importance of formulation design and introduce a novel methodology for evaluating long-term elastomer durability.

Analysis of the laser beam trajectory and its impact on the cut in PMMA material

Wed, 01 Jan 2025 00:00:00 GMT

Analysis of the laser beam trajectory and its impact on the cut in PMMA material Knedlová, Jana; Bílek, Ondřej; Bartík, David Article investigates how laser toolpath interpolation (linear vs. circular) affects kerf width, dimensional accuracy, and kerf taper when CO2-cutting PMMA sheets (t = 3, 5 mm) on an ILS 3NM system (λ = 10.6 μm; P = 100 W). Lenses with f = 1.5″ and 2.5″ were assessed. At identical process settings adopted from prior work, linear toolpaths yielded larger outer dimensions and more pronounced kerf taper, whereas circular paths produced more stable kerf and smaller taper angles. In all cases, the top-surface kerf exceeded the bottom-surface kerf. Thinner sheets (3 mm) were more sensitive to focal length and heat accumulation. The results provide practical guidance for selecting optics and toolpaths to balance accuracy and edge quality in PMMA cutting and form an experimental basis for future AI-assisted process optimization. © Published under licence by IOP Publishing Ltd.