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  • Emulsifying blends based on natural fats for eco-design of O/W emulsions
    • Patrycja Szumała
    • Elżbieta Pyrz
    2024 JOURNAL OF CLEANER PRODUCTION

    Emulsifier blends are most often used to stabilize and modulate the properties of cosmetic and pharmaceutical emulsions, such as skin care or application-related consistency. However, the rational design of such emulsifier blends is often not well understood, especially when their ingredients are natural raw materials. This study aimed to analyze the influence of natural fatty ingredients selected as emulsifiers on the emulsion properties. For this purpose, the stability, microstructure and rheological properties of the produced emulsions were monitored during their storage. The effect of five blends containing fatty alcohols, cetyl palmitate, beeswax, avocado butter and one typical emulsifier, i.e. sorbitan oleate, in various weight proportions, was analyzed. Even though the blends contained only hydrophobic ingredients, O/W type emulsions were obtained. The results indicate that all blends can stabilize O/W emulsions, but with a specific qualitative and quantitative composition. The crystal structures created by the blend components were responsible for the stabilization of all emulsions, but the most beneficial properties were provided by the blend with the addition of beeswax and sorbitan oleate. These findings provide new insights into the design of safe and ecological emulsions.

  • Encapsulation of Cs3Bi2Br9 perovskite photocatalyst with polythiophene for prolonged activity in oxidizing and humid environment
    • Magdalena Miodyńska
    • Olga Kaczmarczyk
    • Wojciech Lisowski
    • Andrzej Żak
    • Tomasz Klimczuk
    • Monika Paszkiewicz
    • Adriana Zaleska-Medynska
    2024 Pełny tekst APPLIED SURFACE SCIENCE

    Despite their growing popularity in modern technology, halide perovskites suffer from susceptibility to oxidation, limiting their applications. Our aim was to enhance Cs3Bi2Br9 perovskite's performance in humid environments through polythiophene encapsulation. This extended its lifespan while preserving photocatalytic abilities, as demonstrated in toluene decomposition experiments. We confirmed the stability of Cs3Bi2Br9 encapsulated with polythiophene over four photocatalytic cycles and identified photogenerated electrons and superoxide radicals as key contributors to toluene decomposition. Benzaldehyde was detected as the primary toluene decomposition product, and we observed partial pollutant mineralization, evidenced by increased CO2 concentration after photocatalysis. Additionally, using hybrid ex–situ transmission electron microscopy, we observed delayed oxidation of encapsulated perovskite. Encapsulation hindered, but did not entirely prevent, water vapor penetration into Cs3Bi2Br9 particles. This progress suggests promising prospects for perovskite–based composites retaining photocatalytic capabilities under elevated humidity conditions.

  • Energy Constrained Depth First Search
    • Shantanu Das
    • Dariusz Dereniowski
    • Przemysław Uznański
    2024 ALGORITHMICA

    Depth first search is a natural algorithmic technique for constructing a closed route that visits all vertices of a graph. The length of such a route equals, in an edge-weighted tree, twice the total weight of all edges of the tree and this is asymptotically optimal over all exploration strategies. This paper considers a variant of such search strategies where the length of each route is bounded by a positive integer $B$ (e.g. due to limited energy resources of the searcher). The objective is to cover all the edges of a tree $T$ using the minimum number of routes, each starting and ending at the root and each being of length at most $B$. To this end, we analyze the following natural greedy tree traversal process that is based on decomposing a depth first search traversal into a sequence of limited length routes. Given any arbitrary depth first search traversal $R$ of the tree $T$, we cover $R$ with routes $R_1,\ldots,R_l$, each of length at most $B$ such that: $R_i$ starts at the root, reaches directly the farthest point of $R$ visited by $R_{i-1}$, then $R_i$ continues along the path $R$ as far as possible, and finally $R_i$ returns to the root. We call the above algorithm \emph{piecemeal-DFS} and we prove that it achieves the asymptotically minimal number of routes $l$, regardless of the choice of $R$. Our analysis also shows that the total length of the traversal (and thus the traversal time) of piecemeal-DFS is asymptotically minimum over all energy-constrained exploration strategies. The fact that $R$ can be chosen arbitrarily means that the exploration strategy can be constructed in an online fashion when the input tree $T$ is not known in advance. Each route $R_i$ can be constructed without any knowledge of the yet unvisited part of $T$. Surprisingly, our results show that depth first search is efficient for energy constrained exploration of trees, even though it is known that the same does not hold for energy constrained exploration of arbitrary graphs.

  • Energy-Efficient Joint User and Power Allocation in 5G Millimeter Wave Networks: A Genetic Algorithm-Based Approach
    • Abdulhalim Fayad
    • Tibor Cinkler
    2024 IEEE Access

    Reducing power consumption is a pivotal challenge in 5G millimeter wave (mmWave) networks due to the density of the base stations (BSs) in these networks. In this paper, we focus on the joint user and power allocation problem in 5G mmWave networks, aiming to minimize power consumption while maintaining the user Quality of Service (QoS), considering the BSs switching on/off strategy. Initially, we formulate the problem as an Integer Linear Program (ILP), aiming to obtain the optimal solution. Due to the NP-hardness of the problem, we propose a Genetic Algorithm (GA)-based heuristic strategy. Extensive simulations are conducted to evaluate the performance of the GA. The obtained results demonstrate the efficiency of the proposed GA in providing close to optimal solutions, even in scenarios with a large number of users, when compared to the ILP. Additionally, the proposed GA outperforms the benchmark algorithms in terms of network power consumption, network throughput, energy efficiency (EE), and the number of switched-off BSs. Moreover, when comparing the running time of the different methods, the proposed GA shows a significantly reduced time compared to the optimal solution obtained by the ILP method. At the same time, it requires a running time close to the running times of the benchmark solutions. Further insights from power consumption patterns in residential and office areas affirm the consistent energy savings achieved by the proposed GA, emphasizing its applicability in real-world scenarios. In our case, the proposed GA yields energy savings up to 22.34% and 33.12% in residential and office areas, respectively. These findings underscore the practicality and efficiency of our proposed GA in optimizing power consumption and enhancing EE in mmWave networks.

  • Energy-Efficient Self-Supervised Technique to Identify Abnormal User Over 5G Network for E-Commerce
    • Arsalan Muhammad Soomar
    2024 IEEE TRANSACTIONS ON CONSUMER ELECTRONICS

    Within the realm of e-commerce networks, it is frequently observed that certain users exhibit behavior patterns that differ substantially from the normative behaviors exhibited by the majority of users. The identification of these atypical individuals and the understanding of their behavioral patterns are of significant practical significance in maintaining order on e-commerce platforms. One such method for accomplishing this objective entails examining the behavioral tendencies of atypical users through the abstraction of e-commerce networks as heterogeneous information networks. These networks are then transformed into a bipartite graph that establishes associations between users and devices. The Self-Supervised Aberrant Detection Model (SAD) has been proposed within this theoretical framework as a means to identify and detect users who exhibit aberrant behavior. The SSADM methodology utilizes a self-supervised learning process that utilizes autoencoders to encode representations of user nodes. The proposed method aims to maximize a combined objective function for backpropagation while utilizing support vector data description to detect abnormalities in the representations of user nodes. In summary, many tests have been conducted utilizing both authentic network datasets and partially synthetic network datasets to demonstrate the efficacy and superiority of the SAD technique, specifically within the domain of an energy-efficient 5G network.

  • Engineering and Management of Space Systems
    • Jasminka Matevska
    • Marek Chodnicki
    • Zbigniew Łubniewski
    2024

    Dynamic development of the European space sector results in a necessity for suitable Higher Education Institution graduates. Current study programs of Aerospace Technology are focused on the field of mechanical engineering. Although engineering methods for design, construction and assembly of mechanical systems are covered, interdisciplinarity and life cycle aspects are not considered in a sufficient degree. Due to the increasing digitalization, interconnection and distribution of technical systems, there is a high necessity to consider the systems with their interdisciplinarity during the entire life cycle from the initial idea through conception, design, production, integration, verification and validation to operation, maintenance and disposal in such a way that it best meets the expectations of the stakeholders and successfully accomplishes the planned mission. Current systems require different competencies depending on the characteristics of the application domain. The increasingly dynamic market requires an adaptation of traditional approaches and the introduction of agile methods in order to meet the requirements for greater flexibility and creativity. This, supplemented by management and social competencies, forms a future-oriented basis for mastering the ever-growing complexity of technical software-intensive systems. Our international interdisciplinary joint Master's double-degree program - Engineering and Management of Space Systems (EMSS) established as a cooperation of Bremen City University of Applied Sciences, Germany and Gdańsk University of Technology, Poland addresses all the above-mentioned systems engineering aspects and imparts competencies necessary to comprehend complex space missions as a "system of systems" during their entire life cycle. It is conducted in cooperation with the local space industry, in particular OHB, Airbus Defence and Space, and Ariane Group.

  • Engineering and Management of Space Systems - an International Joint Master's Double-Degree Programme
    • Jasminka Matevska
    • Marek Chodnicki
    • Zbigniew Łubniewski
    2024 Pełny tekst

    Dynamic development of the European space sector results in a necessity for suitable Higher Education Institution graduates. Current study programs of Aerospace Technology are focused on the field of mechanical engineering. Although engineering methods for design, construction and assembly of mechanical systems are covered, interdisciplinarity and life cycle aspects are not considered in a sufficient degree. Due to the increasing digitalization, interconnection and distribution of technical systems, there is a high necessity to consider the systems with their interdisciplinarity during the entire life cycle from the initial idea through conception, design, production, integration, verification and validation to operation, maintenance and disposal in such a way that it best meets the expectations of the stakeholders and successfully accomplishes the planned mission. Current systems require different competencies depending on the characteristics of the application domain. The increasingly dynamic market requires an adaptation of traditional approaches and the introduction of agile methods in order to meet the requirements for greater flexibility and creativity. This, supplemented by management and social competencies, forms a future-oriented basis for mastering the ever-growing complexity of technical software-intensive systems. Our international interdisciplinary joint Master's double-degree program - Engineering and Management of Space Systems established as a cooperation of Bremen City University of Applied Sciences, Germany and Gdańsk University of Technology, Poland addresses all the above-mentioned systems engineering aspects and imparts competencies necessary to comprehend complex space missions as a "system of systems" during their entire life cycle. It is conducted in cooperation with the local space industry, in particular OHB, Airbus Defence and Space, and Ariane Group.

  • Engineering education for smart grid systems in the quasi-industrial environment of the LINTE^2 laboratory
    • Andrzej Augusiak
    • Filip Kutt
    • Piotr Musznicki
    • Janusz Nieznański
    2024 Global Journal of Engineering Education

    Smart grid systems are revolutionising the electric power sector, integrating advanced technologies to enhance efficiency, reliability and sustainability. It is important for higher education to equip the prospective smart grid professional with the competencies enabling them to navigate through the related complexities and drive innovation. To achieve this, interdisciplinary education programmes are necessary, addressing inter alia integration of renewable energy sources, data analytics, AI and machine learning, cybersecurity, policies and regulatory frameworks. Hands-on experience, industrial training and research-based learning are also highly desirable components of such programmes. This article describes how Gdańsk University of Technology (Gdańsk Tech), Gdańsk, Poland, employs its unique Laboratory for Innovative Power Systems and Integration of Renewable Energy Sources (LINTE^2 Lab), to support comprehensive education in smart grids. Starting with simulation and virtualisation, students gradually extend their knowledge and competencies through project, research and challenge-based activities in the quasi-industrial environment of the LINTE^2 Lab.

  • English Language Learning Employing Developments in Multimedia IS
    • Piotr Odya
    • Adam Kurowski
    • Andrzej Czyżewski
    2024 Pełny tekst

    In the realm of the development of information systems related to education, integrating multimedia technologies offers novel ways to enhance foreign language learning. This study investigates audio-video processing methods that leverage real-time speech rate adjustment and dynamic captioning to support English language acquisition. Through a mixed-methods analysis involving participants from a language school, we explore the impact of auditory, visual, and bimodal input enhancements on learning outcomes. Results reveal that visual enhancements, especially caption highlighting, significantly enhance vocabulary acquisition and pronunciation, whereas simultaneous auditory-visual modifications show less advantage. Overall findings suggest that multimedia-enhanced environments, particularly those emphasizing visual input, can substantially improve language learning efficiency. This research contributes to Information Systems (IS) development education by proposing practical tools and strategies for embedding multimedia content in e-learning, thereby addressing the diverse needs of students in the digital era.

  • Enhanced acceptor concentration, proton conductivity, and hydration in multicomponent rare‐earth ortho‐niobates
    • Arkadiusz Dawczak
    • Wojciech Skubida
    • Aleksandra Mielewczyk-Gryń
    • Maria Gazda
    2024 JOURNAL OF THE AMERICAN CERAMIC SOCIETY

    The structural properties of (La0.2Nd0.2Sm0.2Gd0.2Eu0.2)1−xCaxNbO4−δ (x = 0–0.05) series have been studied by X-ray powder diffraction at room temperature. The thermal properties were investigated using thermogravimetry, from which the concentration of proton defects was determined. Additionally, dilatometry studies were carried out, from which the thermal expansion coefficients and the phase transition temperature between low- and high-temperature polymorphs were determined. In order to determine the electrical properties, the electrochemical impedance spectroscopy measurements under atmospheres of dry synthetic air and saturated with water vapor and heavy water at 300–800°C temperature range were performed. All the studied materials were single-phase compositions and were stable in monoclinic I2/c crystal structure at room temperature. The water uptake studies revealed a small mass change under the switch from dry to humidified synthetic air atmospheres, suggesting the formation of proton defects. The phase transition from monoclinic to tetragonal crystal structure in the (La0.2Nd0.2Sm0.2Gd0.2Eu0.2)1−xCaxNbO4−δ (x = 0–0.05) series occurs above 650°C. A small amount of calcium dopant increases the total conductivity in all tested atmospheres by two orders of magnitude, for example, from 0.34 μS cm−1 in La0.2Nd0.2Sm0.2Gd0.2Eu0.2NbO4 to 63.7 μS cm−1 in (La0.2Nd0.2Sm0.2Gd0.2Eu0.2)0.95Ca0.05NbO4−δ at 700°C in humid synthetic air atmosphere.

  • Enhanced cellulose extraction from agave plant (Agave americana Species) for synthesis of magnetic/cellulose nanocomposite for defluoridation of water
    • Samuel Latebo Majamo
    • Temesgen Amibo
    • Ermias Tsegaw
    2024 Materials Today Communications

    Research on fluoride removal from water is currently focusing on the development of innovative materials for defluoridation water. The current study extracted and used enhanced cellulose from Agave americana species to synthesize a magnetic/cellulose nanocomposite for water defluoridation. Strong and light binary acids (H2SO4 and CH3COOH) were utilized to pretreat raw material to enhance cellulose extraction. Central composite design (CCD) was used to design experiments to find optimum condition for cellulose extraction. Four key factors (H2SO4 to CH3COOH ratio, acid concentration, temperature, and contact time) with three levels were designed by CCD. The lignin, hemicellulose and cellulose content of raw agave cellulosic fiber in this study were 5.5 ± 0.27, 20.5 ± 0.23 and 60.4 ± 0.31 % respectively. While, at the optimum conditions of 2.3 % acid concentration, 0.44 H2SO4 to CH3COOH ratio, 83.2 min of retention time, and 105.5 oC, cellulose content reached 940.25 %. Then, enhanced cellulose was covered with magnetic components, resulting in a magnetic/cellulose nano- composite. The adsorbent materials were characterized by Fourier Transform Infrared (FTIR) spectroscopy, X- Ray Diffractometer (XRD), Scanning electron microscopy (SEM), and Dynamic light scattering (DLS). In addition, textural features of the adsorbent were investigated. All characterization results suggest that the synthesized adsorbent has the required properties. Adsorption tests were carried out using various interaction components. The combined effects of critical process variables on defluoridation were examined. The adsorption isotherm was calculated. Overall, the research demonstrated that the produced magnetic/cellulose nanocomposite can be employed as an efficient and ecologically acceptable adsorbent for fluoride removal from water.

  • Enhanced electrochemical activity of boron-doped nanocarbon functionalized reticulated vitreous carbon structures for water treatment applications
    • Iwona Kaczmarzyk
    • Mariusz Banasiak
    • Paweł Jakóbczyk
    • Michał Sobaszek
    • Gabriel Strugała
    • Tomasz Seramak
    • Paweł Rostkowski
    • Jakub Karczewski
    • Mirosław Sawczak
    • Jacek Ryl
    • Robert Bogdanowicz
    2024 Pełny tekst DIAMOND AND RELATED MATERIALS

    An extraordinary charge transfer kinetics and chemical stability make a boron-doped diamond (BDD) a prom- ising material for electrochemical applications including wastewater treatment. Yet, with flat geometrical sur- faces its scaling options are limited. In this study, the reticulated Vitreous Carbon (RVC) served as a substrate for boron-doped diamondized nanocarbons (BDNC) film growth resulting with complex heterogeneity carbon structures with different morphologies defined by using electron microscopy, microtomography, activation en- ergy studies, and Raman spectroscopy. The proposed modification significantly boosted the electrochemical Fe(CN)6 3 /4 redox activity. The vol- tammetry and impedimetric studies revealed its origin as a significantly higher share of electrochemically active sites at the BDNC@RVC electrode (increased by 114 %) combined with enhanced heterogeneous rate constant (2× increase up to 8.24⋅10 4 cm s 1). Finally, to establish its applicability for water treatment, the BDNC@RVC was studied as the anode in electrochemical paracetamol decomposition. Boron-enriched nanoarchitecture formed at the RVC electrode surface substantially reduced the oxidation energy barrier manifested as a decrease in activation overpotential by 212 mV, which gave a consequence in a 78 % removal rate (in 4 h, at 0.7 mA cm 2), 12 % higher than bare RVC and yielding lower amounts of APAP decomposition intermediates.

  • Enhanced Electrochemical Performance of MnCo1.5Fe0.5O4Spinel for Oxygen Evolution Reaction through Heat Treatment
    • Krystian Lankauf
    • Bartłomiej Lemieszek
    • Karolina Górnicka
    • Patryk Błaszczak
    • Marcin Zając
    • Piotr Jasiński
    • Sebastian Molin
    2024 Pełny tekst ENERGY & FUELS

    MnCo1.5Fe0.5O4 spinel oxide was synthesized using the sol−gel technique, followed by heat treatment at various temperatures (400, 600, 800, and 1000 °C). The prepared materials were examined as anode electrocatalysts for watersplitting systems in alkaline environments. Solid-state characterization methods, such as powder X-ray diffraction and X-ray absorption spectroscopy (XAS), were used to analyze the materials’ crystallographic structure and surface characteristics. The intrinsic activity of the MnCo1.5Fe0.5O4 was fine-tuned by altering the electronic structure by controlling the calcination temperature, and the highest activity was observed for the sample treated at 800 °C. A shift in the valence state of surface cations under oxidative conditions in an alkaline solution during the oxygen evolution reaction was detected through ex situ XAS measurements. Moreover, the influence of the experimental conditions on the electrocatalytic performance of the material, including the pH of the electrolyte and the temperature, was demonstrated.

  • Enhanced electrochemical performance of partially amorphous La0.6Sr0.4CoO3-δ oxygen electrode materials for low-temperature solid oxide cells operating at 400 °C
    • Bartłomiej Lemieszek
    • Mindaugas Ilickas
    • Jan Jamroz
    • Asta Tamulevičienė
    • Jakub Karczewski
    • Patryk Błaszczak
    • Alexey Maximenko
    • Brigita Abakevičiene
    • Marcin Małys
    • Sigitas Tamulevičius
    • Piotr Jasiński
    • Sebastian Molin
    2024 Pełny tekst APPLIED SURFACE SCIENCE

    This work evaluates partially amorphous La0.6Sr0.4CoO3-δ (LSC) as a potential oxygen electrode for lowtemperature solid oxide cells. LSC was deposited using the spin-coating technique onto Ce0.8Gd0.2O2-δ (CGO) substrates. The optimal oxygen electrode thickness was determined as 500 nm. The electrochemical impedance spectroscopy (EIS) study showed a significant improvement in oxygen reduction/oxidation reaction kinetics when annealing temperatures below 600 ◦C. The lowest value of the polarisation resistance was observed for the sample annealed at 400 ◦C, followed by a temperature of 500 ◦C. EIS measurements at different pO2 content were performed at levels between 0.5 % and 20 %. A comprehensive equivalent circuit analysis was carried out for an explanation of the limiting factors of the catalytic reaction. X-ray absorption fine structure analysis allowed for the identification of differences between crystalline LSC and its partially amorphous form. X-ray absorption nearedge spectroscopy analysis indicated that cobalt adopts a lower oxidation state for the partially amorphous form. Moreover, extended X-ray absorption fine structure analysis indicated the decreased of cobalt oxidation state in partially amorphous LSC. It can be assumed that the increased activity of LSC at temperatures below the crystallization may be due to increased defects and oxygen vacancies in the material.

  • Enhanced electrochemical performance of SnS-PPy-carbon black composite with a locust bean gum as a binder as in anode in lithium-ion batteries
    • Ewelina Rudnicka
    • Maciej Galiński
    • Paweł Jakóbczyk
    2024 JOURNAL OF APPLIED ELECTROCHEMISTRY

    Water-soluble binders—locust bean gum (LBG) and carboxymethyl cellulose (CMC) were tested with the SnS anode modified by new conducting material polypyrrole—carbon black composite (PPyCB) and compared with the environmentally unfriendly widely used polyvinylidene fluoride (PVdF) as an organic binder. The electrochemical properties of tested electrodes were investigated by galvanostatic charging/discharging tests, cyclic voltammetry, and electrochemical impedance spectroscopy. Kinetic parameters of electrode processes were calculated from resistances. The first discharge capacities were 2150 mAh g−1, 1250 mAh g−1, and 960 mAh g−1 for SnS-PPyCB-LBG, SNS-PPyCB-CMC, and SnS-PPyCCB-PVdF, respectively. The exchange current density for the SnS-PPyCB electrode is in the range of 4.6 × 10−6 mA cm−2 for the system with carboxymethyl cellulose to 1.97 × 10−6 mA cm−2 in the cell with LBG. Compared to PVdF, locust bean gum is an equally effective binder and may even enhance electrode kinetics.

  • Enhanced encoder–decoder architecture for visual perception multitasking of autonomous driving
    • Muhammad Usman
    • Muhammad Zaka-Ud-Din
    • Qiang Ling
    2024 EXPERT SYSTEMS WITH APPLICATIONS

    Visual perception plays a vital role in autonomous driving systems, demanding high accuracy and real-time inference speed to ensure safety. In this paper, we propose a multi-task framework that simultaneously performs object detection, drivable area segmentation, and lane line identification, addressing the requirements of accurate and efficient visual perception. Our approach utilizes a shared-encoder architecture with three separate decoders, targeting each specific task. We investigate three configurations for the shared encoder: a Convolutional Neural Network (CNN), a Polyp Vision Transformer (PVT), and a hybrid CNN+PVT model. Through extensive experimentation and comparative analysis on the challenging BD100K dataset, we evaluate the performance of these shared-encoder models and provide valuable insights into their strengths and weaknesses. Our research contributes to the advancement of multi-task visual perception for autonomous driving systems by achieving competitive results in terms of accuracy and efficiency. The source code is publicly available on GitHub to facilitate further research in this domain.

  • Enhanced Mechanical and Electromechanical Properties of Compositionally Complex Zirconia Zr1–x(Gd1/5Pr1/5Nd1/5Sm1/5Y1/5)xO2−δ Ceramics
    • Ahsanul Kabir
    • Bartłomiej Lemieszek
    • Maxim Varenik
    • Victor Buratto Tinti
    • Sebastian Molin
    • Igor Lubomirsky
    • Vincenzo Esposito
    • Frank Kern
    2024 Pełny tekst ACS Applied Materials & Interfaces

    Compositionally complex oxides (CCOs) or high-entropy oxides (HEOs) are new multi-element oxides with unexplored physical and functional properties. In this work, we report fluorite structure derived compositionally complex zirconia with composition Zr1- x(Gd1/5Pr1/5Nd1/5Sm1/5Y1/5)xO2-δ (x = 0.1 and 0.2) synthesized in solid-state reaction route and sintered via hot pressing at 1350 °C. We explore the evolution of these oxides' structural, microstructural, mechanical, electrical, and electromechanical properties regarding phase separation and sintering mechanisms. Highly dense ceramics are achieved by bimodal mass diffusion, composing nanometric tetragonal and micrometric cubic grains microstructure. The material exhibits an anomalously large electrostriction response exceeding the M33 value of 10−17 m 2 /V2 at room temperatures and viscoelastic properties of primary creep in nanoindentation measurement under fast loading. These findings are strikingly similar to those reported for doped ceria and bismuth oxide derivates, highlighting the presence of a large concentration of point defects linked to structural distortion and anelastic behavior are characteristics of nonclassical ionic electrostrictors.

  • Enhanced Spectroscopic Insight into Acceptor-Modified Barium Strontium Titanate Thin Films Deposited via the Sol–Gel Method
    • Dionizy Czekaj
    • Agata Lisińska-Czekaj
    2024 Pełny tekst Materials

    In the present paper, composite thin films of barium strontium titanate (BaxSr1−xTiO3) with an acceptor modifier (magnesium oxide—MgO) were deposited on metal substrates (stainless steel type) using the sol–gel method. The composite thin films feature BaxSr1−xTiO3 ferroelectric solid solution as the matrix and MgO linear dielectric as the reinforcement, with MgO concentrations ranging from 1 to 5 mol%. Following thermal treatment at 650 °C, the films were analyzed for their impedance response. Experimental impedance spectra were modeled using the Kohlrausch–Williams–Watts function, revealing stretching parameters (β) in the range of approximately 0.78 to 0.89 and 0.56 to 0.90 for impedance and electric modulus formalisms, respectively. Notably, films modified with 3 mol% MgO exhibited the least stretched relaxation function. Employing the electric equivalent circuit method for data analysis, the “circle fit” analysis demonstrated an increase in capacitance from 2.97 × 10−12 F to 5.78 × 10−10 F with the incorporation of 3 mol% MgO into BST-based thin films. Further analysis based on Voigt, Maxwell, and ladder circuits revealed trends in resistance and capacitance components with varying MgO contents, suggesting non-Debye-type relaxation phenomena across all tested samples.

  • Enhanced visible light-activated gas sensing properties of nanoporous copper oxide thin films
    • Andrzej Kwiatkowski
    • Janusz Smulko
    • Katarzyna Drozdowska
    2024 Pełny tekst SOLAR ENERGY MATERIALS AND SOLAR CELLS

    Metal oxide gas sensors are popular chemoresistive sensors. They are used for numerous tasks, including environmental and safety monitoring. Some gas-sensing materials exhibit photo-induced properties that can be utilized for enhanced gas detection by modifying the sensor selectivity and sensitivity when illuminated by light. Here, we present the gas sensing characteristics of highly nanoporous Cu2O thin films towards both electrophilic (NO2) and nucleophilic (C2H5OH, NH3) gas molecules under ambient temperature and modulated by visible light illumination of different colors (red: 632 nm, green: 530 nm, blue: 468 nm). Cu2O films were fabricated by reactive advanced gas deposition (AGD) technology. The surface and structural analysis of the samples confirm the deposition of nanoporous thin films of mixed copper oxide phases. The gas sensing property of Cu2O exhibited expected p-type semiconductor behavior upon electrophilic and nucleophilic gas exposures. Our results show that visible light illumination provides enhanced sensor response.

  • Enhancing Business Process Management Through Nature Assessment: Development and Deployment of the Business Process Nature Assessment Tool
    • Marzena Grzesiak
    • Marek Szelągowski
    • Marek Moszyński
    • Justyna Berniak-Woźny
    2024

    In contemporary business landscapes, the diverse nature of processes necessitates a thor-ough assessment before implementing Business Process Management (BPM). However, conducting such assessments can be arduous, particularly for small and medium-sized en-terprises. This study aims to address this challenge by developing and showcasing the utility of an online tool based on the Business Process Nature Assessment Framework (BPNAF). The BPNAF facilitates integrated assessments of business processes, aligning with estab-lished BPM methodologies and lifecycles. Through an illustrative case study, this research examines the efficacy of this tool in assessing the processes / nature. The BPNA tool ena-bles swift and effective evaluations of process unpredictability and knowledge intensity, aiding in selecting appropriate BPM methodologies, Knowledge Management (KM) and Human Resource Management (HRM) strategies, and supporting IT systems. Visualised results offer clear recommendations tailored to the organisation's unique process landscape, accommodating standard and customised recommendations. By contributing insights into practical BPNAF implementation, this study plays a pivotal role in advancing BPM assess-ment methodologies and enriching the understanding and practice of BP management. This research underscores the critical role of BP assessment in organisational success, advocating for informed decision-making and best practices in BPM.