Budapest University of Technology and Economics

Polyhydroxyalkanoates (PHAs) are gaining increasing attention in the biodegradable polymer market due to their promising properties such as high biodegradability in different environments, not just in composting plants, and processing versatility.Indeed among biopolymers, these biogenic polyesters represent a potential sustainable replacement for fossil fuel-based thermoplastics.Most commercially available PHAs are obtained with pure microbial cultures grown on renewable feedstocks (i.e.glucose) under sterile conditions but recent research studies focus on the use of wastes as growth media.PHA can be extracted from the bacteria cell and then formulated and processed by extrusion for production of rigid and flexible plastic suitable not just for the most assessed medical applications but also considered for applications including packaging, moulded goods, paper coatings, non-woven fabrics, adhesives, films and performance additives.The present paper reviews the different classes of PHAs, their main properties, processing aspects, commercially available ones, as well as limitations and related improvements being researched, with specific focus on potential applications of PHAs in packaging.

Starch is a natural polymer which possesses many unique properties and some shortcoming simultaneously.Some synthetic polymers are biodegradable and can be tailor-made easily.Therefore, by combining the individual advantages of starch and synthetic polymers, starch-based completely biodegradable polymers (SCBP) are potential for applications in biomedical and environmental fields.Therefore it received great attention and was extensively investigated.In this paper, the structure and characteristics of starch and some synthetic degradable polymers are briefly introduced.Then, the recent progress about the preparation of SCBP via physical blending and chemical modification is reviewed and discussed.At last, some examples have been presented to elucidate that SCBP are promising materials for various applications and their development is a good solution for reducing the consumption of petroleum resources and environmental problem.

Polylactic acid (PLA), one of the well-known biodegradable polyesters, has been studied extensively for tissue engineering and drug delivery systems, and it was also used widely in human medicine.A new method to synthesize PLA (ring-opening polymerization), which allowed the economical production of a high molecular weight PLA polymer, broadened its applications, and this processing would be a potential substitute for petroleum-based products.This review described the principles of the polymerization reactions of PLA and, then, outlined the various materials properties affecting the performance of PLA polymer, such as rheological, mechanical, thermal, and barrier properties as well as the processing technologies which were used to fabricate products based on PLA.In addition, the biodegradation processes of products which were shaped from PLA were discussed and reviewed.The potential applications of PLA in the medical fields, such as tissue engineering, wound management, drugs delivery, and orthopedic devices, were also highlighted.

Flax fibre was modified with acetylation.The influence of the acetylation on the structure and properties of flax fibre were investigated as well as modified flax fibre reinforced polypropylene composites were also prepared.The catalyst was used to accelerate acetylation reaction rate.Flax fibre was characterised after modification.Surface morphology, moisture absorption property, components content, degree of polymerisation, crystallinity of cellulose and thermal stability of flax fibres were studied.Due to acetylation, the flax fibre surface morphology and moisture resistance properties improved remarkably.Flax fibre (modified and unmodified) reinforced polypropylene composites were fabricated with 30 wt% fibre loading.The mechanical properties were investigated for those composites.Tensile and flexural strengths of composites were found to increase with increasing degree of acetylation up to 18% and then decreased.Charpy impact strengths of composites were found to decrease with increasing degree of acetylation.Owing to addition of coupling agent (maleated polypropylene -MAH), the tensile and flexural strength properties were found to increase in between 20 to 35% depending on degree of acetylation.

The amalgamation of polymer and pharmaceutical sciences led to the introduction of polymer in the design and development of drug delivery systems.Polymeric delivery systems are mainly intended to achieve controlled or sustained drug delivery.Polysaccharides fabricated into hydrophilic matrices remain popular biomaterials for controlled-release dosage forms and the most abundant naturally occurring biopolymer is cellulose; so hdroxypropylmethyl cellulose, hydroxypropyl cellulose, microcrystalline cellulose and hydroxyethyl cellulose can be used for production of time controlled delivery systems.Additionally microcrystalline cellulose, sodium carboxymethyl cellulose, hydroxypropylmethyl cellulose, hydroxyethyl cellulose as well as hydroxypropyl cellulose are used to coat tablets.Cellulose acetate phthalate and hydroxymethyl cellulose phthalate are also used for enteric coating of tablets.Targeting of drugs to the colon following oral administration has also been accomplished by using polysaccharides such as hdroxypropylmethyl cellulose and hydroxypropyl cellulose in hydrated form; also they act as binders that swell when hydrated by gastric media and delay absorption.This paper assembles the current knowledge on the structure and chemistry of cellulose, and in the development of innovative cellulose esters and ethers for pharmaceuticals.

The state-of-art and key problems of carbon nanotube (CNT) based polymer composites (CNT/polymer composites) including CNT/polymer structural composites and CNT/polymer functional composites are reviewed.Based on the results reported up to now, CNTs can be an effective reinforcement for polymer matrices, and the tensile strength and elastic modulus of CNT/polymer composites can reach as high as 3600 MPa and 80 GPa, respectively.CNT/polymer composites are also promising functional composite materials with improved electrical and thermal conductivity, etc. Due to their multi-functional properties, CNT/polymer composites are expected to be used as low weight structural materials, optical devices, thermal interface materials, electric components, electromagnetic absorption materials, etc.However, the full potential of CNT/polymer composites still remains to be realized.A few key problems, such as how to prepare structurecontrollable CNTs with high purity and consistently dependable high performance, how to break up entangled or bundled CNTs and then uniformly disperse and align them within a polymer matrix, how to improve the load transfer from matrix to CNT reinforcement, etc, still exist and need to be solved in order to realize the wide applications of these advanced composites.

The use of slow release fertilizer has become a new trend to save fertilizer consumption and to minimize environmental pollution.Due to its polymeric cationic, biodegradable, bioabsorbable, and bactericidal characteristics, chitosan (CS) nanoparticle is an interesting material for use in controlled release systems.However, there are no attempts to explore the potential of chitosan nanoparticles as controlled release for NPK fertilizers.In this work chitosan nanoparticles were obtained by polymerizing methacrylic acid for the incorporation of NPK fertilizers.The interaction and stability of chitosan nanoparticle suspensions containing nitrogen (N), phosphorus (P) and potassium (K) were evaluated by FTIR spectroscopy, particle size analysis and zeta-potential.The FTIR results indicated the existence of electrostatic interactions between chitosan nanoparticles and the elements N, P and K.The stability of the CS-PMAA colloidal suspension was higher with the addition of nitrogen and potassium than with the addition of phosphorus, due to the higher anion charge from the calcium phosphate than the anion charges from the potassium chloride and urea.The mean diameter increase of the CS-PMAA nanoparticles in suspension with the addition of different compounds indicated that the elements are being aggregated on the surface of the chitosan nanoparticles.

In this work Raman spectroscopy was used for extensive characterization of multiwall carbon nanotube (MWNTs) and of MWCNTs/rubber composites.We have measured the Raman spectra of bundled and dispersed multiwall carbon nanotubes.All the Raman bands of the carbon nanotubes are seen to shift to higher wavenumbers upon debundling on account of less intertube interactions.Effects of laser irradiation were also investigated.Strong effects are observed by changing the wavelength of the laser excitation.On the other hand, at a given excitation wavelength, changes on the Raman bands are observed by changing the laser power density due to sample heating during the measurement procedure.

Formation of microcracks is a critical problem in polymers and polymer composites during their service in structural applications.Development and coalescence of microcracks would bring about catastrophic failure of the materials and then reduce their lifetimes.Therefore, early sensing, diagnosis and repair of microcracks become necessary for removing the latent perils.In this context, the materials possessing self-healing function are ideal for long-term operation.Self-repairing polymers and polymer composites have attracted increasing research interests.Attempts have been made to develop solutions in this field.The present article reviews state-of-art of the achievements on the topic.According to the ways of healing, the smart materials are classified into two categories: (i) intrinsic self-healing ones that are able to heal cracks by the polymers themselves, and (ii) extrinsic in which healing agent has to be pre-embedded.The advances in this field show that selection and optimization of proper repair mechanisms are prerequisites for high healing efficiency.It is a challenging job to either invent new polymers with inherent crack repair capability or integrate existing materials with novel healing system.

Natural fibers, as replacement of engineered fibers, have been one of the most researched topics over the past years.This is due to their inherent properties, such as biodegradability, renewability and their abundant availability when compared to synthetic fibers.Synthetic fibers derived from finite resources (fossil fuels) and are thus, affected mainly by volatility oil prices and their accumulation in the environment and/or landfill sites as main drawbacks their mechanical properties and thermal properties surpass that of natural fibers.A combination of these fibers/fillers, as reinforcement of various polymeric materials, offers new opportunities to produce multifunctional materials and structures for advanced applications.This article intends to cover recent developments from 2013-up to date on hybrid composites, based on natural fibers with other fillers.Hybrid composites preparation and characterization towards their applicability in advanced applications and the current challenges are also presented.

The latest edition of DigComp 2.2. highlights the educational potential to develop AI competences and skills in the educational processes. Hence, the aim of the present study is to investigate how these competences and skills can be developed in religious education through gamification. By comparing the AI competences and skills development opportunities of DigComp 2.2 and the V-VIII-grade Romanian religious education curriculum, this study seeks and assesses the possibilities of how religious education can develop these abilities. As far as the development of students' AI skills is essential, it is the task of religious education to go deeper and to lay the foundations for the development of moral decision-making through gamification in the face of the challenges of the digital world.

There are growing concerns about the safety and health implications of electric scooters, where the quality of road surfaces and speed are factors to be considered. The purpose of this study is to contribute to this research field by analyzing the effect of pavement types on vibration at various speeds.This study was conducted in Győr, Hungary, where four types of road pavement were analyzed: concrete (bicycle lane), asphalt (shared use) and two types of brick pavers (bicycle lane and pedestrian walkway). Three speed categories, 10, 15, and 20 km/h, were considered. Peak and RMS acceleration data were gathered and analyzed using boxplots, cumulative distribution functions, and various statistical tests. Finally, ride comfort was investigated based on RMS acceleration. Results show that both peak acceleration and RMS acceleration are affected by pavement type as well as riding speed. Concrete pavement yielded the lowest acceleration values followed by red brick pavers for bicycles and asphalt pavement, while gray brick pavers for pedestrians showed the worst results. The increase in speed resulted in higher peak and RMS acceleration values; however, the volume of this change depends on the type of pavement. Changing the type of pavement and the speed will result in statistically significant differences in vertical acceleration. The study stresses the importance of considering the types of road pavement, their intended use as well as riding speed. With an increase in speed, pavement types with low level of quality contribute to a higher increase in acceleration values.

Acid mine drainage (AMD) is a major environmental concern characterized by low pH and elevated concentrations of heavy metals such as iron and manganese, requiring effective and sustainable treatment methods. This study investigates the use of industrial fly ash waste as a low-cost adsorbent, enhanced through alkali-leaching modification to produce a zeolite-like material with improved adsorption performance. The novelty of this work lies in the application of alkali-leached fly ash to simultaneously enhance adsorption capacity and neutralization ability for AMD treatment. Adsorbent characterization was conducted using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET) analyses. BET results showed that modification significantly increased the specific surface area (14 m2/g) and pore volume (0.025 cm3/g). SEM-EDX results revealed a predominantly spherical morphology and changes in elemental composition following modification. XRD analysis showed partial dissolution of minor phases during alkali leaching, resulting in increased dominance of the quartz (SiO2) phase with a main peak at 2θ = 26.59°. Batch adsorption experiments were performed under varying adsorbent dosages (10–100 g) to evaluate metal removal and pH improvement. The results demonstrated that modified fly ash increased AMD pH from 3.45 to 7.21 and achieved high removal efficiency of Mn, reducing its concentration to 0.05 mg/L (removal efficiency > 95%). Compared to untreated fly ash, the modified adsorbent exhibited significantly enhanced performance. The treated AMD met Indonesian Class I water quality standards. These findings highlight the potential of alkali-leached fly ash as an effective and sustainable adsorbent for AMD remediation.

In recent years, the field of electromobility has been developing very dynamically in Poland and worldwide. Due to the necessity of adapting road and energy infrastructure, a forecast of the development of the electric vehicle market was required. The aim of this article is to develop a forecast of the number of electric vehicles in Poland for the years 2024–2030. For this purpose, an analysis of annual data on the number of electric vehicles in Poland was conducted. Selected neural network models were used for the forecast. The results of the study indicate that the number of electric vehicles in Poland is expected to continue growing. On one hand, this is influenced by European Union policies, and on the other, by the dynamic technological advancements in the field of electromobility. The choice of sample sizes (training, testing, and validation) significantly impacts the obtained results.

Songs have long been recognised as beneficial tools in the English as a Foreign Language (EFL) classroom (Adnyani, Dewi, 2020; Kumar et al., 2022). However, a recurring challenge occurs in the selection of appropriate songs. Educators often struggle to find a piece of music that features grammatically correct lyrics, possesses catchy melodies, and has a convincing topic at the same time. Moreover, some songs contain the desired structures and phrases, only a few times throughout their lyrics. Recent advances in generative artificial intelligence (e.g. SunoAI, iLoveSong.ai) offer promising solutions to these challenges by enabling the creation of customised and personalised songs. With the help of AI assistance, teachers and learners can generate materials that support autonomy and cater to specific linguistic goals. This article presents the theoretical and practical concepts of integrating AI-generated songs into the EFL classrooms.

This article explores the integration of technological tools into interpreter training. While translation training has incorporated digital and AI-based technologies for a relatively long period, empirical research shows that interpreters' familiarity with specialised Computer-Assisted Interpreting (CAI) tools remains low. In response to this gap, the Department of Translation and Interpreting at Eötvös Loránd University launched Technology for Interpreters, an innovative pilot course that systematically introduces interpreting-related technologies. The course combines theoretical guidance with hands-on practice across multiple modules, including CAI software, telephone interpreting, tablet-supported interpreting, artificial intelligence, simultaneous interpreting and remote interpreting. Experience shows that this approach strengthens key technological skills, such as digital literacy, effective tool use and AI awareness. Several challenges remain, particularly regarding resources, instructor training and the fast pace of technological change. Overall, the study indicates that integrating CAI tools into interpreter education is both possible and educationally beneficial, and the initiative presented may serve as a useful reference point for other institutions interested in launching similar courses.

This study aims to improve the estimation of concrete compressive strength by combining destructive and non-destructive testing (ultrasound and sclerometer) to obtain a more precise and reliable assessment for quality control and the diagnosis of concrete structures. The experimental data were analyzed using a program linked to the Pundit Lab measurement tool to establish a regression model linking the ultrasonic propagation velocity (UPV) to the compressive strength of self-compacting concrete (SCC). SCC was formulated using a standard mix design with 450 kg/m3 of cement, 10% limestone filler (45 kg/m3), a water/cement ratio of 0.44, a gravel/sand ratio of 1.0, and a polycarboxylate-based superplasticizer. The fresh properties were evaluated using cone slump tests, L-box tests, V-funnel tests, and sieve stability tests, confirming the self-compacting nature of the mix. After 28 days of curing, five cylindrical specimens (160 × 320 mm) were subjected to ultrasonic (UPV), sclerometric, and compression tests. The results showed an average compressive strength of 39.06 MPa, a modulus of elasticity of 41.5 GPa, and a shear modulus of 16.7 GPa. The developed regression model improved the accuracy of compressive strength estimation by combining ultrasonic and sclerometric measurements, thus providing a reliable method for quality control and evaluation of existing concrete structures.

The COVID-19 pandemic served as a brutal stress test for museum resilience. While many institutions relied on a 'substitutive model' of mere digital replacement, the National Museum of Korea (NMK) achieved anomalous growth through a strategic pivot. This study employs an explanatory single-case study design to investigate the mechanisms behind this success. Applying pattern matching logic, the research validates the efficacy of a 'Transformative Model' grounded in Cultural Democracy. Findings reveal that the NMK's integration of AI-driven personalization, immersive Extended Reality (XR) experiences, and radical inclusivity reconfigured the visitor relationship from passive consumption to active co-creation. Crucially, empirical data confirms a positive correlation where high-level digital engagement functioned as a catalytic gateway that drove, rather than cannibalized, physical attendance. This case illustrates how sustainable resilience can be achieved when technology is strategically deployed to democratize heritage access and empower the visitor as an active participant.

The COVID-19 pandemic served as a brutal stress test for museum resilience. While many institutions relied on a 'substitutive model' of mere digital replacement, the National Museum of Korea (NMK) achieved anomalous growth through a strategic pivot. This study employs an explanatory single-case study design to investigate the mechanisms behind this success. Applying pattern matching logic, the research validates the efficacy of a 'Transformative Model' grounded in Cultural Democracy. Findings reveal that the NMK's integration of AI-driven personalization, immersive Extended Reality (XR) experiences, and radical inclusivity reconfigured the visitor relationship from passive consumption to active co-creation. Crucially, empirical data confirms a positive correlation where high-level digital engagement functioned as a catalytic gateway that drove, rather than cannibalized, physical attendance. This case illustrates how sustainable resilience can be achieved when technology is strategically deployed to democratize heritage access and empower the visitor as an active participant.

The article presents a comparative analysis of road traffic fatalities in Poland and the European Union (EU-27) in the context of implementing the "Vision Zero" strategy. The study covers the period 2014–2023 and employs absolute and per capita indicators (fatalities per 1 million inhabitants) to assess safety trends. Log-linear models and joinpoint analysis were applied to estimate the average annual percent change (APC) and identify shifts in trend dynamics. Results indicate a significant reduction in road fatalities in Poland (−40.9% absolute, −38.1% per 1 million inhabitants) and in the EU-27 (−15.6% absolute, −16.4% per 1 million inhabitants). The APC in Poland (−5.68% absolute, −5.26% per capita) was more than twice as high as the EU average, with a notable acceleration after 2019, likely influenced by infrastructure improvements, enhanced law enforcement, and pandemic-related traffic reductions. Despite progress, Poland's fatality rate remains slightly above the EU average, highlighting the need for continued system-wide safety measures. The findings demonstrate the effectiveness of a Safe System Approach and provide evidence-based recommendations for achieving the intermediate 2030 targets of Vision Zero.