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New insights into structural, optical, electrical and thermoelectric behavior of Na0.5Bi0.5TiO3 single crystals
- G. Jagło
- Kamila Kluczewska-Chmielarz
- J. Suchanicz
- A. Kruk
- A. Kania
- D. Sitko
- M. Nowakowska-Malczyk
- Marcin Łapiński
- G. Stachowski
2025 Pełny tekst Scientific Reports
The single crystals of lead-free Na0.5Bi0.5TiO3 were grown using the Czochralski method. The energy gaps determined from X-ray photoelectron spectroscopy (XPS) and optical measurements were approximately 2.92 eV. The current-voltage characteristics, depolarization current, dc (σdc) and ac (σac) electrical conductivity, and Seebeck coefficient of the crystals were investigated. The frequency/temperature-dependent electrical properties were also measured and analyzed through complex impedance spectroscopy. An overlapping reversible insulator-metal transition (resistive switching) on nanoscales, caused by the electric field, was detected. Most of these properties were measured for the first time. The activation energy values determined from the conductivity data, the imaginary part of the electric impedance and the modulus indicate that the relaxation process in the high-temperature range is attributable to both single and double ionized oxygen vacancies, in combination with the hopping of electrons between Ti4+ and Ti3+. P-type electrical conductivity was also found. These discoveries create new possibilities of reducing the electrical conductivity of NBT and improving the process of effectively poling this material. Our results indicate the possibility of tuning the material properties by intentionally creating non-stoichiometry/structural defects (oxygen vacancies, cation excess and cation deficiency).
Noisy (Binary) Searching: Simple, Fast and Correct
- Dariusz Dereniowski
- Aleksander Łukasiewicz
- Przemysław Uznański
2025
This work considers the problem of the noisy binary search in a sorted array. The noise is modeled by a parameter p that dictates that a comparison can be incorrect with probability p, independently of other queries. We state two types of upper bounds on the number of queries: the worst-case and expected query complexity scenarios. The bounds improve the ones known to date, i.e., our algorithms require fewer queries. Additionally, they have simpler statements, and work for the full range of parameters. All query complexities for the expected query scenarios are tight up to lower order terms. For the problem where the target prior is uniform over all possible inputs, we provide an algorithm with expected complexity upperbounded by (log₂ n + log₂ δ^{-1} + 3)/I(p), where n is the domain size, 0 ≤ p < 1/2 is the noise ratio, and δ > 0 is the failure probability, and I(p) is the information gain function. As a side-effect, we close some correctness issues regarding previous work. Also, en route, we obtain new and improved query complexities for the search generalized to arbitrary graphs. This paper continues and improves the lines of research of Burnashev-Zigangirov [Prob. Per. Informatsii, 1974], Ben-Or and Hassidim [FOCS 2008], Gu and Xu [STOC 2023], and Emamjomeh-Zadeh et al. [STOC 2016], Dereniowski et al. [SOSA@SODA 2019].
Numerical Simulation of Light to Heat Conversion by Plasmonic Nanoheaters
- Maria Nevárez Martínez
- Dominik Kreft
- Maciej Grzegorczyk
- Sebastian Mahlik
- Narajczyk Magdalena
- Adriana Zaleska-Medynska
- P. Demosthenes Morales
- Jennifer Hollingsworth
- James Werner
2025 Pełny tekst NANO LETTERS
Plasmonic nanoparticles are widely recognized as photothermal conversion agents, i.e., nanotransducers or nanoheaters. Translation of these materials into practical applications requires quantitative analyses of their photothermal conversion efficiencies (η). However, the value of η obtained for different materials is dramatically influenced by the experimental setup and method of calculation. Here, we evaluate the most common methods for estimating η (Roper’s and Wang’s) and compare these with numerical estimates using the simulation software ANSYS. Experiments were performed with colloidal gold nanorod solutions suspended in a hanging droplet irradiated by an 808 nm diode laser and monitored by a thermal camera. The ANSYS simulations accounted for both heating and evaporation, providing η values consistent with the Wang method but higher than the Roper approach. This study details methods for estimating the photothermal efficiency and finds ANSYS to be a robust tool where experimental constraints complicate traditional methods.
On a fully three-dimensional bending analysis of very thick smart composite cube-like bulk structures
- Mohammad Malikan
- Shahriar Dastjerdi
- Victor Eremeev
- Mehran Kadkhodayan
2025 Pełny tekst COMPOSITE STRUCTURES
Here we discuss the behaviour of very thick composite plates considering electro-magneto-elastic coupling of various types using fully three-dimensional (3D) kinematics. Published research highlights a lack of studies on the 3D mechanics of smart composite plates that integrate both higher-order (flexoelectric/flexomagnetic) and lower-order (piezoelectric/piezomagnetic) multiple physical fields (electro-magneto-elastic). The common approach to achieving the targeted and desired mechanical behavior within such composites could involve using structural elements. This gap can potentially be addressed by amalgamating the term ∂/∂z with the 2D governing equations of plates. This expression indicates alterations in thickness, in which z is the coordinate dedicated to the thickness. The governing equations can be created by operating on the variational method which enables us to establish and settle the 3D bending equations of the bulk structure. The pointed-out equations have been influenced by the implementation of additional hypotheses, such as von Kármán’s strain and complicated 3D tensor relations. Inserting the term ∂/∂z into the mathematical model renders that the analytical solution techniques are unable to assist us in obtaining numerical results. Consequently, a semi-analytical solving method grounded on the polynomial phrases facilitates the acquisition of the required solution. This fully 3D bending study of very thick piezocomposite cube-like bulk structures (CBS) can be an original reference in the field of mechanics of intelligent plate-like structures.
On nonlinear 3D electro-elastic numerical modeling of two-phase inhomogeneous FG piezocomposites reinforced with GNPs
- Mohammad Malikan
- Shahriar Dastjerdi
- Magdalena Rucka
- Mehran Kadkhodayan
2025 Pełny tekst INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
The novelty here comes from not only the perfect nonlinear three-dimensional (3D) electro-elasticity investigation but also the mixed material itself. The literature widely showed mechanical assessments on the piezoelectric structures; however, a lack of nonlinear three-dimensional elasticity studies has been witnessed on these kinds of smart materials. Therefore, a nonlinear 3D elasticity-piezoelectricity coupling is considered in this study. What is more, this research brings about an era in the field of sensing manufacturing such as sensors and actuators by proposing the construction of these devices in an advanced composite framework. The piezoelectric medium can be electro-mechanically improved with the aggregation of graphene platelets/nanoplatelets (GPLs/GNPs) based on the functionally graded (FG) composition. The assumption for such a smart composite has been made to provide higher flexibility smart tools while their elastic strength can also get further. To accomplish this, the derivation of a rigorous mathematical model has come out for a transversely isotropic inhomogeneous FG-piezoelectric beam-like sensor/actuator using 3D kinematic displacements, geometrically nonlinear strains, Lagrange technique, 3D stress-strains tensors, linear elastic material, and in particular Halpin-Tsai micro-mechanic model. Numerical modeling has been built by the generalized differential quadrature (GDQ) technique. A comprehensive parametric study has also been established for intelligent FG beams.
On the use of black tea waste as a functional filler for manufacturing self-stabilizing polyethylene composites: In-depth thermal analysis
- Joanna Aniśko-Michalak
- Paulina Kosmela
- Mateusz Barczewski
2025 INDUSTRIAL CROPS AND PRODUCTS
Thermal and oxidative stabilization are critical aspects in the processing and exploitation of polyolefins. Black tea contains many natural antioxidants, the largest group of compounds in its composition. When used as a filler for composite manufacturing, the thermo-oxidation process of polyethylene can be slowed down. Black tea waste (BTW) generated during the process of packing tea into sachets was introduced into a bio-based low-density polyethylene (LDPE) as a filler. The composites containing 1, 2, 5, and 10 wt% were produced by melt extrusion. In order to assess the antioxidant capacity of the used filler, an analysis was carried out using the DPPH solution on both the filler extracts and the produced composites. The total phenolic content and total flavonoid content analysis were also carried out on black tea waste extracts. Thermogravimetric analysis of composites was held in an inert and oxidative atmosphere, and data from the test in a nitrogen atmosphere was used to calculate degradation kinetics. The composites were also evaluated in terms of their thermal behavior by differential scanning calorimetry (DSC) to describe their crystallization process and oxidation induction time (OIT) to confirm stabilization effects caused by functional waste fillers on polyethylene. Adding 10 wt% of black tea waste elongates OIT nearly 36 times compared to LDPE. The thermo-oxidation process was also conducted at 90 °C for 1, 2, 4, 7, 11 and 15 days. The composites aged this way were subjected to the FTIR test. Thanks to this study, the carbonyl index (CI) was determined, which showed that adding tea waste limits the oxidation of polyethylene.
Opposite effect of the Cu photodeposition on the ∙OH generation and diclofenac degradation depends on the exposed anatase facet
- Szymon Dudziak
- Jakub Smoliński
- Adam Ostrowski
- Aleksandra Szkudlarek
- Mateusz Marzec
- Krystian Sokołowski
- Karol Sikora
- Anna Zielińska-Jurek
2025 Pełny tekst CHEMICAL ENGINEERING JOURNAL
Exposition of a specific crystal facets and modification with co-catalysts are often used in order to improve photocatalytic activity of a material. However, considering complexity of these interactions, it is still challenging to fully understand and predict activity of a specific system. Here, we report combination of the {0 0 1} and {1 0 1} crystal facets of anatase TiO2 with CuXO co-catalyst, applied for diclofenac degradation, ∙OH generation and 4-nitrophenol reduction. Interestingly, we observed opposite effect of Cu for ∙OH generation and DCF degradation, with clear enhancement of the activity observed only for the {0 0 1} facets. EPR measurements further proved that for the most active material in this series, Cu exist as an atomically-scattered Cu2+ species at the surface, achieved as the result of high surface development and high adsorption energy (from DFT). Based on the absorbance measurements and XPS analysis, these species are shown to be further reduced to Cu2O during degradation process. Compared to this, all other systems ({1 0 1} and all results for nitrophenol) showed reduction of the activity due to the CuXO presence. In this regard, CuXO cannot be seen as an universal reduction co-catalyst for TiO2, with final effect being clearly dependent on exposed facet and reaction. This is despite TiO2/CuXO was found to form analogical, well-known Z-scheme junction in case of both surfaces. Ultimately, we showed that specifically {0 0 1} with CuXO make highly synergistic combination for ROS generation.
Optimal bandgap of a single-junction photovoltaic cell for the mobile Internet-of-Things
- Grażyna Jarosz
- Ryszard Signerski
2025 iScience
The procedure for determining the maximum power of a single-junction photovoltaic cell operating in various types of lighting is presented. This is a key issue for photovoltaics powering the mobile Internet-of-Things (IoTs). The simulations performed are based on the detailed balance principle, without any of simplifying assumptions included in the Shockley-Queisser model. Optimal energy bandgap for diffuse solar light was found to be 1.64 eV with a cutoff generated power of 37.3 W/m2. For the LED lighting considered in this work, the optimal energy bandgap and maximum power limit are 1.86 eV, 1.63 W/m2 and 1.79 eV, 1.51 W/m2 for cool and warm lighting, respectively, at 900 lux. Considering that the maximum power limit of diffuse solar radiation is much higher than the limit for LED lighting, we concluded that 1.64 eV is the optimal bandgap for most mobile IoT devices operating outdoors all or almost all the time.
Optimization of constitutive law for objective numerical modeling of knitted fabric
- Agnieszka Tomaszewska
- Daniil Reznikov
2025 JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
This paper discusses the problem of macroscopic modeling a knitted technical fabric with the aim to determine a constitutive law for adequately modeling the material response under real-life load. As phenomenological, hyperelastic material laws reveal different parameters due to different test modalities used to identify such parameters, an optimization scheme is proposed to determine an objective solution. The study is conducted for three medical textiles which are differentiated by anisotropy ratios and designed to cover abdominal hernia. The optimization parameters are defined by a constitutive law and the bi-axial test modality. State variables are taken from ex-vivo reference tests on ‘operated’ hernia models subjected to simulated real-life loads generated by post-operative coughs. The objective function is different for isotropic and anisotropic mesh. However, in both cases a numerical model of a mesh placed in the abdominal wall with different variants of the constitutive law is used. The model is constructed according to the finite element method framework. The objective function for isotropic mesh is defined by the variance of reaction forces in mesh fixation points, calculated in the numerical model, while for anisotropic mesh, it is generated by the difference between angles which determine the position of maximal reaction force in the numerical and experimental reference models. Three constitutive laws and five modalities of bi-axial tests are considered. This analysis proves the need for a constitutive model, itself validated by a suitable reference test, instead of an arbitrary decision on bi-axial test modality selected to identify the material law parameters. These conclusions may help to increase the reliability of numerical modeling of operated hernia and increase the effectiveness of hernia treatment
Optimization of Hydrogen Utilization and Process Efficiency in the Direct Reduction of Iron Oxide Pellets: A Comprehensive Analysis of Processing Parameters and Pellet Composition
- Angelo Perrone
- Pasquale Cavaliere
- Behzad Sadeghi
- Leandro Dijon
- Aleksandra Mirowska
2025 Pełny tekst STEEL RESEARCH INTERNATIONAL
The article deals with the H2 consumption for different processing conditions and the composition of the processed pellets during the direct reduction process. The experiments are carried out at 600–1300 °C, with gas pressures of 1–5 bar, gas flow rates of 1–5 L min−1, and basicity indices of 0 to 2.15. Pellets with different compositions of TiO2, Al2O3, CaO, and SiO2 are analyzed. The gas flow rate is crucial, with 0–10 L min−1 leading to an H2 consumption of 0–5.1 kg H2/kg pellet. The gas pressure (0–10 bar) increases the H2 consumption from 0 to 5.1 kg H2/kg pellet. Higher temperatures (600–1300 °C) reduce H2 consumption from 5.1 to 0 kg H2/kg pellet, most efficiently at 950–1050 °C, where it decreases from 0.22 to 0.10 kg H2/kg pellet. An increase in TiO2 content from 0% to 0.92% lowers H2 consumption from 0.22 to 0.10 kg H2/kg pellet, while a higher Fe content (61–67.5%) also reduces it. An increase in SiO2 content from 0% to 3% increases H2 consumption from 0 to 5.1 kg H2/kg pellet. Porosity structure influences H2 consumption, with the average pore size decreasing from 2.83 to 0.436 mm with increasing TiO2 content, suggesting that micropores increase H2 consumption and macropores decrease it.
Optimizing conductivity in Na-V-Te-O glass through controlled heat treatment
- Michalina Wanat
- Piotr Okoczuk
- Marcin Łapiński
- Barbara Kościelska
- Stefania Wolff
- Sharafat Ali
- Natalia Wójcik
2025 CERAMICS INTERNATIONAL
Semiconducting Na2O-V2O5-TeO2 glasses with various Na2O contents were melted and subjected to controlled heating to improve conductivity. Topography analysis were performed using confocal microscopy and scanning electron microscopy on both as-quenched and heat-treated samples. X-ray diffraction confirmed the amorphous nature of the samples post-melting, with subsequent heating resulting in the formation of nanocrystallites primarily composed of vanadium ions. The Na2O addition caused progressive depolymerization of the tellurite-vanadate network, as evidenced by IR spectroscopy, although heating exhibited an opposing effect, particularly noticeable in vanadate-related bands. Thermal properties revealing a decrease in the glass transition temperature, crystallization process, and thermal stability with increasing sodium ion concentration. Electrical properties were investigated using impedance spectroscopy, which enabled determination of DC conductivity values, polaron jump energies, and disturbance energies in the samples. The electrical conductivity mechanisms were described as mixed ionic-polaronic, with polaron hopping predominating. Heat treatment significantly enhanced polaron conductivity and altered its nature.
Optimizing nature-based solutions for urban flood risk mitigation: A multi-objective genetic algorithm approach in Gdańsk, Poland
- Anahita Azadgar
- Artur Gańcza
- Sina Razzaghi Asl
- Stefano Salata
- Lucyna Nyka
2025 SCIENCE OF THE TOTAL ENVIRONMENT
Nature-based Solutions (NbS) have emerged as a sustainable approach to managing flood risks by enhancing natural water retention and reducing surface runoff in urban areas. As climate change and rapid urbanization exacerbate flood hazards, optimizing the spatial deployment of NbS is crucial for improving urban resilience and mitigating flood impacts. This study presents a comprehensive optimization framework for the spatial allocation of fourteen different NbS types aimed at mitigating urban flood risks in Gdańsk, Poland. Leveraging a genetic algorithm alongside the Urban Flood Risk Mitigation (UFRM) model of the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) software suite, we identified areas of the city most vulnerable to pluvial flooding and optimized NbS placement to maximize water retention and reduce runoff. The optimization process balanced multiple objectives, including minimizing implementation costs and maximizing water retention capacity, ensuring that the solutions are both economically feasible and environmentally effective. Three distinct scenarios were proposed: a cost-effective solution, a high-retention solution, and a balanced solution, offering urban planners a range of strategies to address flood risks based on their specific priorities and constraints. Results demonstrated considerable variations in water retention effectiveness across different NbS configurations, with denser urban regions showing the most significant improvements from targeted interventions. The optimized placement of NbS resulted in estimated total water retention improvement of approximately 15.5 % for the best solution considered. These findings provide valuable insights for integrating NbS into urban flood management strategies, enhancing citywide resilience, sustainability, and long-term flood mitigation.
Paving the way for green cross-linker substances for the fabrication of polymer membranes — a review
- Roberto Castro Munoz
- Grzegorz Boczkaj
2025 Current Opinion in Chemical Engineering
Chemical cross-linking in membrane fabrication aims to face limitations of polymer membranes, including poor chemical resistance, low mechanical stability, swelling, etc. Typical cross-linkers do not fit green chemistry and sustainable principles due to their toxicity. Thus, this article discusses the successful application of green cross-linkers (including organic acids — citric, gallic, ferulic, and tannic acid, calcium chloride, deep eutectic solvents, pectin) and less toxic substances in polymer membranes (including biopolymeric ones based on chitosan or cellulose) fabrication. This article also mentions how to make it ‘greener’. Important areas for these developments include food biopackaging materials, 3D printing materials, and biomedical items.
Phages as potential life-saving therapeutic option in the treatment of multidrug-resistant urinary tract infections
- Beata Zalewska-Piątek
- Michalina Nagórka
2025 Pełny tekst Acta Biochimica Polonica
Urinary tract infections (UTIs) are among the most common bacterial infections worldwide and increasing antimicrobial resistance (AMR) challenges conventional antibiotic treatments. Phage therapy (PT) has emerged as a promising alternative due to its specificity, safety and efficacy against multidrug-resistant (MDR) pathogens causing infectious diseases. PT demonstrates significant potential in treating chronic and recurrent UTIs, also including catheter-associated infection by reducing bacterial biofilms, delaying catheter blockage, and enhancing antibiotic efficacy when used in combination. Clinical trials and case studies have reported high rates of bacterial eradication and symptom improvement with minimal side effects. Although endotoxin release and immune activation during treatment should continue to be investigated. The aim of this review is to present issues related to the use of phages in the treatment of UTIs of various etiological origins in selected patients, including those with comorbidities, taking into account the legal regulations, safety and effectiveness of this experimental therapy. The growing prevalence of MDR uropathogens highlights the urgent need for alternative therapies, such as those based on phages in order to treat antibiotic-resistant infections and improve patient outcomes. Despite the great potential of PT, its clinical implementation and use of phages as a routine treatment for bacterial infections requires rigorous trials, standardized production protocols and regulatory advancements.
Photocatalytic activity of zinc oxide nanorods incorporated graphitic carbon nitride catalyst
- Shanmugapriya Dharani
- Arunachalam Saravana Vadivu
- Anna Zielińska-Jurek
- Arunachalam Chinnathambi
- Md Ramesh
- Matias Soto-Moscoso
2025 Journal of the Taiwan Institute of Chemical Engineers
Background Photocatalysts are user-friendly and serve as compatible materials for degrading industrial dye pollutants. This study utilizes zinc oxide/graphitic carbon nitride (ZnO/g-C3N4) nanocomposites against degrading methylene blue (MB). Methods The hydrothermal method assisted sonication technique was used to fabricate the ZnO/g-C3N4 composite with varying ratios of ZnO/g-C3N4 (1:0.25, 1:0.50, 1:1). The synthesized materials have undergone various sophisticated techniques for finding their physiochemical properties and have been utilized for photodegradation activities. Significant findings The characterized results exhibit that the nanoflakes of g-C3N4 were covered with nanorods of zinc oxide when observed through scanning electron microscopy (SEM). Furthermore, the X-ray diffraction (XRD) studies demonstrate that the ZnO/g-C3N4 material was successfully synthesized. The X-ray photoelectron spectra (XPS) and Fourier-transform infrared (FTIR) spectra revealed the present oxidation states and chemical bonding of the materials. The photocatalytic activity results demonstrated that the concentration of ZnO molar ratio in varying g-C3N4 significantly affected the decomposition performance. The ZnO/g-C3N4 (1:0.50) presented a higher rate of degradation, reaching 92% at 120 minutes under UV light and 65% at 240 minutes under visible light irradiation. This could be explained by the mechanism that follows the separation of charge carriers, thereby producing hydroxyl radicals for the effective degradation of MB pollutants.
Photocatalytic membranes based on Cu–NH2-MIL-125(Ti) protected by poly(vinylidene fluoride) for high and stable hydrogen production
- Emilia Gontarek-Castro
- Anna Pancielejko
- Mateusz Baluk
- Malwina Kroczewska-Gnatowska
- Przemysław Gnatowski
- Krzysztof Matus
- Justyna Łuczak
- Adriana Zaleska-Medynska
2025 Materials Horizons
A porous, photocatalytically active, and water-stable composite membrane has been developed based on Cu–NH2-MIL-125(Ti), a titanium-based metal–organic framework (MOF) and PVDF polymeric matrix. To tune the structural and functional properties of the PVDF/MOF composites, the loading degree of the MOF within the polymer was systematically varied. The most effective performance of the composite material was achieved with a 10% wt/wt loading of MOF into the PVDF matrix. Analysis of the photoactivity under UV-vis revealed that increasing the MOF content from 1 to 10% led to an improvement in the H2 production rate from 86.0 to 389.1 umol h1 m2 and from 55.5 to 466.0 lmol h1 m2 for water-based and AcN-based electrolytes, respectively. Furthermore, the stability of the MOF is significantly improved when incorporated into the PVDF matrix, maintaining its structural integrity even after 20 h of the photoprocess. The SEM images and EDX mapping successfully validate the presence of the MOF within the PVDF matrix following the photoprocess. The study outlines the experimental procedures for synthesizing Cu–NH2-MIL-125(Ti), preparing PVDF composites, and details on the photocatalytic experiments. The practical application of our approach can be further expanded to enhance the photocatalytic performance of PVDF-protected unstable MOFs.
Photocatalytic selectivity oxidation of 2-phenoxy-1-phenylethanol coupled with Cd-MOF/S/Ni-NiO for hydrogen evolution performance and mechanism
- Ying Zhang
- Afaq Hassan
- Jiang Li
- Jide Wang
2025 Catalysis Science & Technology
In this study, Cd-MOF/S/Ni–NiO (MOF = metal–organic framework) composite materials were prepared using a hydrothermal synthesis method and employed for the high-efficiency photocatalytic oxidation of the lignin β-O-4 model compound 2-phenoxy-1-phenylethanol, coupled with water splitting hydrogen evolution. The Cd-MOF/S/Ni–NiO composite material retained the petal-like morphology of Cd-MOF, with Ni-BTC acting as the precursor for Ni–NiO, effectively preventing metal agglomeration. Without the addition of Ni–NiO, the main photocatalytic oxidation products of 2-phenoxy-1-phenylethanol were phenol and acetophenone, and only 2.6% of 2-phenoxy-1-phenylethanone was produced, with a hydrogen production rate of 102 μmol g−1 h−1. However, after the addition of 1 mmol Ni–NiO, 2-phenoxy-1-phenylethanol was almost completely converted, with phenol and acetophenone yields of 30% and 32%, respectively. The yield of 2-phenoxy-1-phenylethanone increased to 62%, and the hydrogen production rate reached 1058 μmol g−1 h−1. It was found that the addition of an appropriate amount of Ni–NiO facilitated the formation of the oxidation product of 2-phenoxy-1-phenylethanone. The reaction mechanism was subsequently verified, revealing that h+ is the main oxidizing species in the photocatalytic oxidation of 2-phenoxy-1-phenylethanol. This work demonstrates a dual-optimized catalytic system for the highly selective oxidation of lignin β-O-4 model compounds, coupled with simultaneous hydrogen production, providing new insights into the high-value application of lignin in the catalytic conversion of polymetallic oxides.
Physicochemical properties of La0.5Ba0.5Co1-xFexO3-δ (0≤x≤1) as positrode for proton ceramic electrochemical cells
- Sebastian Wachowski
- Iga Szpunar
- Joanna Pośpiech
- Daria Balcerzak
- Aleksandra Mielewczyk-Gryń
- Małgorzata Nadolska-Dawidowska
- María Balaguer
- José M Serra
- Einar Vøllestad
- Maria Gazda
- Ragnar Strandbakke
- Truls Norby
2025 Pełny tekst ACTA MATERIALIA
We report on essential properties of materials in the series La0.5Ba0.5Co1-xFexO3-δ as positrodes for proton ceramic electrochemical cells (PCECs). The unit cell and thermochemical expansion coefficient (TCEC) of these cubic perovskites decrease with iron content x, the TCEC of La0.5Ba0.5FeO3-δ going as low as 11·10-6 1/K. The materials behave as LaMO3 perovskites with small band gaps and Ba acting as acceptors compensated by electron holes and oxygen vacancies. The electrical properties are dominated by p-type conduction with high large polaron mobilities for the Co-rich compositions at low temperatures, shifting towards small polaron mobilities with increasing Fe content. X-ray absorption spectroscopy (XAS) shows that Co is in a high spin state and takes on the main part of the cation oxidation state changes, and that hole states are in orbitals overlapping with the O 2p states, confirming the large polaronic behaviour, while holes on Fe are more localised at the cation. Hydration is more pronounced in inert atmospheres, as hydration of oxygen vacancies is easier than hydrogenation and increases with Fe content, in line with the commonly accepted finding that delocalization of holes disfavours protonation. Fe-rich compositions benefit from lower TCEC and higher hydration and hence expected proton permeability, at the cost of lower electronic conductivity. The surfaces are hydrophobic irrespective of Fe content, suggesting weak chemisorption of the underlaying water layer, possibly giving relatively many available surface sites for oxygen adsorption, but limited surface proton conductance – both of importance to positrodes for operando PCECs.
Plasma in fabrication and modification of polymeric membranes
- Vahid Vatanpour
- Roberto Castro Munoz
- Başak Keskin
- Ismail Koyuncu
2025 DESALINATION
Polymer materials are mostly used in the fabrication of permeable and selective interfaces, known as membranes, for distinct membrane processes. According to their application in membrane processes, there is a need to improve specific properties such as functionality, charge, stability, hydrophilicity and chemical/physical resistance. Mostly, the surface post-modification of the membranes is suitable. In this regard, plasma, as an active area for the functionalization of materials, has been extensively applied for the fabrication and modification of membranes to tailor membrane surfaces and structures and thus produce outperforming membranes. This review timely reviews the different plasma treatments in polymer membranes, including oxidative plasma, CO2, water vapor, reductive, inert plasma, corona discharge, radio-frequency discharge, dielectric barrier discharge, microwave discharge, direct current, and laser-based sources. Here, the principles, advantages, and disadvantages of the various plasma processes used in membrane fabrication and modification were addressed. Particular emphasis has been paid to the effect of the plasma treatment on the separation performance of membranes when implemented in different membrane processes for selective separations, such as membrane gas separation, liquid filtration, pervaporation and membrane distillation. After reviewing the literature, the perspectives and research gaps in the field are given as well.
Polymer Materials for U-Shaped Optic Fiber Sensors: A Review
- Patryk Sokołowski
- Jacek Łubiński
- Paweł Wierzba
- Jakub Czubek
- Piotr Miluski
- Filip Janiak
- Shanyue Guan
- Małgorzata Szczerska
2025 Photonics
Fiber optic sensors have gained popularity over the last few decades. This is due to their numerous advantages, such as good metrological parameters, biocompatibility and resistance to magnetic and electric fields and environmental pollution. However, those built from glass fiber have one main disadvantage—they are fragile, meaning they can be easily damaged, even by the presence of vibration. Due to the great progress made by material research recently, it is possible to build such a sensor with polymer fibers instead. Although those fibers have worse transmission parameters compared to telecommunication fibers, they provide the possibility to realize flexible fiber optic sensors. Taking into consideration other advantages of such fibers, including biocompatibility, electromagnetic resistance and even, biodegradation characteristics, as well as there being a variety of materials we can use, it can be seen that those materials are beneficial to produce fiber optic sensors. This paper aims to provide researchers with guidelines on the factors to consider when choosing a material for bent fiber optic sensors, depending on the application.