In state-of-the-art positron emission tomography (PET), information about annihilation photon polarization is unavailable. Here, we present a PET scanner built from plastic scintillators, where annihilation photons primarily interact via the Compton effect, providing information about both photon polarization and propagation direction. Using this plastic-based PET, we determined the distribution of the relative angle between polarization planes of photons from positron-electron annihilation in a porous polymer. The amplitude of the observed distribution is smaller than predicted for maximally quantum entangled two-photon states but larger than expected for separable photons. This result can be well explained by assuming that photons from pick-off annihilation are not entangled, while photons from direct and parapositronium annihilations are maximally entangled. Our result indicates that the degree of entanglement depends on the annihilation mechanism in matter, opening avenues for exploring polarization correlations in PET as a diagnostic indicator.

The article presents results of research on an adjustable check valve. In particular, the article deals with improvement of flow characteristics and reduction in pressure losses of an existing valve design. The subject of the research was the valve body in the form of a steel block intended for mounting a typical cartridge valve insert. Two variants of the valve body were analysed: a standard one, which is currently in production, and the proposed new solution, in which the geometry was modified based on the results of CFD simulations. The main research task was to properly shape and arrange holes and flow channels inside the body, between the cartridge valve and the connecting plate. Using CFD analyses, a solution for minimising the flow resistance was sought and then the method of modifying flow channels geometry was developed. The CFD simulation results showed a significant reduction in pressure loss, up to 40%. The obtained simulation results were verified on a test bench using a prototype of the proposed valve block. A high degree of consistency in the results of CFD simulations and laboratory experiments was achieved. The relative difference between simulation and experimental results in the entire considered range of the flow rate did not exceed $6.0$%.

The tanks designed for liquefied natural gas transport must be thermally insulated from the environment due to the low condensing temperature of the gas. The effectiveness of thermal insulation significantly affects the tank's operating parameters and its operating costs. As there is no perfect insulation, there is a need for analyses that would determine its suitability in specific applications. In this paper the issue of heat transfer through double-walled cryogenic tanks with evacuated insulation system was discussed. Afterwards the study of insulation variants of liquefied natural gas cryogenic road tanker was presented. The use of several layers of insulation made of modern and efficient materials such as aero-gel and fiberglass or the use of multi-layer isolation has been considered and compared to the use of perlite powder. The heat flux through insulation systems was tested for different variants of evacuated insulation under residual gas pressure of 10-1 Pa, 10-3 Pa, and 100 kPa. Finally, for selected insulation variants, the heat leakage was tested for 50 m3 liquefied natural gas road tanker. The investigation of heat-flow for the transient thermal analysis was performed by applying finite element method. The aim of the study was to determine the variant of insulation system with the relatively low heat leakage to the tank and low cost of materials and vacuum production.

The main purpose of the work which was carried out and is presented in this paper was to examine the possibility of using fuzzy logic inference for conducting a risk analysis with the help of a sheet-based Failure Mode and Effects Analysis method (FMEA). At the beginning, the main features of the analysed method were presented, with particular emphasis put on the Risk, Priority and Number parameters. Then, a proposal has been made which suggests using Matlab Fuzzy Logic Toolbox package in order to convert the factors into the form of fuzzy sets and to define rules for fuzzy inference process has been made. Finally, the created fuzzy logic model was used to present an example analysis of a turbocharger failure in the fuzzified form.

The main aim of this work was to create a model and carry out simulation tests of a hydraulic system for generating a pressure pulse with strictly defined time parameters. Obtaining a proper pressure course is a key condition for correctness of a long-term testing of hydraulic components durability, including e.g. new types of hoses. The requirements regarding the shape of the impulse were formulated on the basis of the ISO 6803:2008 standard which concerns hydraulic pressure testing of rubber hoses and hose assemblies without flexing. In the first step, a mathematical model of the system was built using equations describing the system geometry, flow equations and flow balances formulated for the separated volumes. Next, a simulation model of the hydraulic system was created in Matlab-Simulink. After obtaining flow characteristics, a model of a required pressure signal generator was built, followed by a fuzzy logic controller created in the Anfis editor of the Fuzzy Logic Toolbox. During the iterative tuning process, parameters of the fuzzy controller were adjusted. Then, the curves of the obtained and the required pressure for different values of the flow rate of the working medium were compared. As arises from the comparison results, the fuzzy logic controller fulfills the requirements and thus may be an advantageous option for generating the pressure signal.

Objective: Positron emission tomography (PET) is a widely used medical imaging technique that allows for non-invasive imaging of metabolic processes. However, traditional PET scanners rely on costly inorganic scintillators that limit their accessibility, especially in light of emerging long axial field-of-view devices. The modular J-PET scanner, an innovative alternative, uses 50-cm-long plastic scintillator strips, offering a cost-effective and modular solution. In this study we develop and assess the PET data correction techniques required for quantitative image reconstruction. Methods: We present methods for attenuation correction, random coincidence correction using the delayed time window (DTW) technique and scatter correction based on Monte Carlo simulations. Phantom studies using the NEMA IQ phantom were performed to qualitatively evaluate these corrections. Results: The results demonstrate that our implemented corrections for attenuation and random and scattered coincidences successfully improve the uniformity of tracer distribution in homogenous volumes and significantly reduce undesired activity in cold regions. Despite limitations in sensitivity and axial resolution, the applied correction techniques effectively enhance image quality, providing promising results for future applications. Conclusions: These findings highlight the potential of the modular J-PET system to offer affordable PET imaging and to pave the way for a total-body PET scanner based on plastic scintillators. Future work will focus on quantitative validation and the implementation of these corrections for human subject imaging.