2025 - Repozytorium publikacji - Politechnika Gdańska

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Joint foreign ownership and global value chains effects on productivity: a comparison of firms from Poland and Germany
- Sabina Szymczak
- Aleksandra Parteka
- Joanna Wolszczak-Derlacz
2025 Pełny tekst International Journal of Emerging Markets
Purpose The study aims to examine the joint effects of foreign ownership (FO) and involvement in global value chains (GVCs) on the productivity performance of firms from a catching-up country (Poland) and a leader economy (Germany). Design/methodology/approach The authors use micro-level data on firms combined with several sector-level GVC participation measures. The authors investigate whether the link between productivity and the overall sectoral degree of involvement in global production structures depends on a firm's ownership. The authors verify the robustness of the obtained results by using an instrumental variables approach and weighted regression. Findings The results show that domestically owned firms are less productive than foreign ones, which is particularly true at low GVC participation levels. However, as GVC involvement increases, the FO productivity premium decreases, leading to productivity catching up between foreign and domestically owned firms. This mechanism is similar in Poland and Germany. However, in the leader country (Germany), the productivity performance of domestically owned firms is more stable along the distribution of GVC involvement. Originality/value This study contributes to the foreign direct investment (FDI)–productivity literature by comparing the catching-up and developed countries' perspectives and incorporating the productivity–GVC relationship into the FDI analysis. The authors show that the FO premium is not confined to the developing context but is also present in a leader country. Moreover, the link between productivity and the overall sectoral degree of involvement in global production structures depends on a firm's ownership.
Learning from mistakes within organizations: An adaptive network-oriented model for a double bias perspective for safety and security through cyberspace
- Wioleta Kucharska
- Jan Treur
- Mojgan Hosseini
2025
Although making mistakes is a crucial part of learning, it is still often being avoided in companies as it is considered as a shameful incident. This goes hand in hand with a mindset of a boss who dominantly believes that mistakes usually have negative consequences and therefore avoids them by only accepting simple tasks. Thus, there is no mechanism to learn from mistakes. Employees working for and being influenced by such a boss also strongly believe that mistakes usually have negative consequences but in addition they believe that the boss never makes mistakes, it is often believed that only those who never make mistakes can be bosses and hold power. That's the problem, such kinds of bosses do not learn. So, on the one hand, we have bosses who select simple tasks to be always seen as perfect. Therefore, also they believe they should avoid mistakes. On the other hand, there exists a mindset of a boss who is not limited to simple tasks, he/she accepts more complex tasks and therefore in the end has better general performance by learning from mistakes. This then also affects the mindset and actions of employees in the same direction. This chapter investigates the consequences of both attitudes for the organizations. It does so by computational analysis based on an adaptive dynamical systems modeling approach represented in a network format using the self-modeling network modeling principle.
Magnetic deep eutectic solvents for vortex-assisted liquid phase microextraction method for selective and green extraction of patulin from fruits and fruit juices
- Hameed Ul Haq
- Grzegorz Boczkaj
- Nail Altunay
2025 MICROCHEMICAL JOURNAL
In this study, a vortex assisted magnetic deep eutectic solvent based liquid phase microextraction (VA-MDES-LPME) technique was developed for the extraction of patulin prior to its determination by ultraviolet–visible spectrophotometry (UV–Vis). For this purpose, the use of a magnetic deep eutectic solvent (MDES) consisting of trihexyltetradecylphosphonium chloride, MnCl2, and octanoic acid (molar ratio 1:2:2) was tested to perform an efficient extraction. Important experimental parameters (MDES-3 vol, pH, vortex time, and ethanol volume) were optimized using Box-Behnken Design. Under optimum conditions (MDES-3 vol 560 µL, pH 3.5, vortex time 300 s, and ethanol volume 300 µL), the limits of detection for the model solution and matrix-matched solution were 0.06 ng mL−1 and 0.37 ng mL−1, and the calibration ranges were 0.2–400 ng mL−1 and 1.2–300 ng mL−1, respectively. Furthermore, the extraction recovery was calculated to be 96.3–97.4 % with a low relative standard deviation (2.1–2.5 %). The VA-MDES-LPME technique was successfully applied for the determination of patulin from fruit and juice samples with an enrichment factor between169 and 185.
Mechanical performance investigations of a post-tensioned inter-module connection in steel buildings
- Marcin Kujawa
- Łukasz Smakosz
- Piotr Iwicki
- Aleksander Perliński
- Andrzej Tejchman-Konarzewski
2025 Structures
Connections in modular steel structures are critical for maintaining structural integrity and facilitating ease of installation. Traditional methods, such as on-site welding, require adherence to complex technical specifications. In contrast, post-tensioned steel bolts offer a viable alternative by potentially reducing on-site labor by up to 50 %, providing substantial strength and simplifying assembly. To accurately assess the load-carrying capacity of post-tensioned steel connections, it is essential to analyze slip and shear load. This study investigates the behavior of a post-tensioned inter-module connection. Experimental and numerical analyses were conducted to evaluate the mechanical connection’s performance under shear load. Laboratory tests on connection specimens assessed their strength and failure characteristics, while a finite element model was validated through these experiments. A satisfactory agreement between numerical simulations and experimental findings was found. A detailed numerical study examined the effect of bolt preload and wall friction coefficient on the load-carrying capacity of the connection. The higher bolt preload and higher wall friction coefficient enhanced the stiffness and shear strength of the connection. Additionally, a kinematic forcing method was used to evaluate the translational and rotational stiffnesses of a single post-tensioned modular connection. The elastic shear stiffness was also estimated from a simple analytical bolt model. Based on this solution, a connection optimization problem was formulated using selected design variables. The investigation findings offer valuable insights into the design of modular steel structures with structural connections.
Mechanical properties of 3D-printed polylactide and short carbon fibres reinforced polylactide laminate subjected to environmental aging
- Angela Andrzejewska-Sroka
- Magdalena Rucka
2025 Advances in Science and Technology Research Journal
In this work the mechanical characterisation of fused filament fabricated non-reinforced polylactide and polylactide reinforced with short carbon fibre laminate after environmental aging was reported. In the manufacturing process, the symmetric laminate was used to determine the influence of environmental aging of 3D printed parts. The sterilisation agents and buffered saline solution environment were used as aging factors. Also, the fracture surfaces of non-reinforced and reinforced specimens were imaged with scanning electron microscopy. It was found that short carbon fibres in general influence the higher mechanical strength of materials compared to materials without fibres. But at the same time the addition of short carbon fibre influence of significant loos of toughness when aged with sterilisation agents and buffered saline solution environment during one, six or twelve weeks. The results presented in this work are important for several reasons. The study highlights how the addition of short carbon fibres enhances the mechanical properties of polylactide (PLA), which is valuable for applications requiring increased strength and stiffness, while also addressing the impact of environmental aging, particularly in sterilization and buffered saline solution environment.This is crucial in understanding the mechanical behavior of these materials, as many PLA applications (e.g., in medical devices or marine environments) involve exposure to conditions like mentioned above. Understanding how aging affects a material's mechanical properties helps project lifetime and reliability of products.
Mechanistic insights and atmospheric implications of the degradation reaction of 3-methoxy-1-propanol by reaction with hydroxyl radicals and identification of the end products in the presence of O2/NO
- Abolfazl Shiroudi
- Theo Kurtén
- Jacek Czub
2025 Scientific Reports
The study investigated the degradation of 3-methoxy-1-propanol (3M1P) by OH using the M06-2X/6-311++G(d,p) level, with CCSD(T) single-point corrections. We focused on hydrogen atom abstraction from various alkyl groups within the molecule. The rate coefficient for 3M1P degradation was calculated from the sum of the rate coefficients corresponding to the removal of H-atoms from primary (-CH3), secondary (-CH2-), tertiary (-CH<), and alcohol (-OH) groups. The primary attack by hydroxyl radicals occurs at the hydrogen atom bonded to carbon atoms adjacent to the oxygen atom in the ether group, leading to the formation of alkyl radicals. The computed overall rate constant is 1.85×10‒11 cm3 molecule‒1 sec‒1 at atmospheric pressure and room temperature, which is consistent with the experimental value of (2.15*0.28)×10‒11 cm3 molecule‒1 sec‒1. This strong agreement confirms the reliability of the computational approach, which provides insights into the atmospheric reactivity and degradation pathways of 3M1P. The tropospheric lifetime of 3M1P is around 15 hours, indicating rapid degradation in the atmosphere, potentially contributing to photochemical smog formation. The average ozone production from 3M1P emissions is ~2.1 ppb, with estimated photochemical ozone creation potential (POCP) values of 44 and 43 for north-west European and USA-urban conditions, respectively. These values indicate a moderate risk of photochemical smog production and potential harm to human health and the environment due to 3M1P emissions. Successive pathways involve the addition of molecular oxygen to the energized adducts [3M1P], forming [3M1P−O2] peroxy radicals, which primarily react with nitric oxide to produce nitrogen dioxide and the [3M1P−O] alkoxy radicals. The major degradation products include methyl formate, 3-hydroxypropyl formate, glycolaldehyde, and 3-methoxypropanal.
Metamodel-based optimization of a high-tension cable barrier in crash tests with a large SUV
- Dawid Bruski
- Hongbing Fang
2025 ENGINEERING STRUCTURES
Road safety barriers play an important role in improving road safety. Cable barriers are one of the types of road barriers. Cable barriers have favorable collision-related properties, especially in terms of the safety of the vehicle occupants. Despite the continuous development of road barrier systems, the current European standard EN1317, which is used to evaluate the performance of road barriers, does not take into account all possible crash scenarios and all possible types of impacting vehicles. Sport utility vehicles (SUVs) are one of the types of vehicles that the EN1317 standard does not consider. SUVs are widely used on European roads. The work aims to optimize a high-tension 3-cable barrier system in crash tests with a large SUV. The research utilized the methods related to the design of the experiment, numerical simulations of crash tests, metamodeling, and multi-objective optimization (MOO) algorithms – WSF and NSGA-II. In the optimization, two aspects of the barrier were considered, economical and structural. The primary result of the study was the determination of four optimized designs for the cable barrier. These designs represent different trade-offs between the objective functions, offering various solutions depending on the specific engineering needs. The proposed barrier designs are characterized, among others, by a reduction in barrier mass, a reduction in the lateral deflections of the barrier, and a reduction in the number of posts that would need to be replaced after an SUV collision. The methodology used and the results achieved may be useful in the process of designing, testing, and optimizing other road safety barriers.
Methods and Instruments | Scanning Electrochemical Microscopy
- Gunther Wittstock
- Marius Muhle
- Monika Wilamowska-Zawłocka
2025
Scanning electrochemical microscopy is based on the recording of electrolysis currents (Faradaic currents) at a microelectrode (ME) probe that is scanned over the sample. Different working modes are available to couple the electrolysis at the ME to reactions at the sample. The article explains their principles and provides examples of their application. The feedback mode, the sample-generation/tip collection mode, the redox-competition mode and the surface interrogation mode are most frequently applied to the characterization of interphases and interfaces occurring in electrochemical power sources.
MHD Casson flow across a stretched surface in a porous material: a numerical study
- Sadia Irshad
- Shah Jahan
- Jose Mendes Machado
- Paweł Śliwiński
- Krzysztof Kędzia
- Zubair Ahmed Jan
2025 Multiscale and Multidisciplinary Modeling, Experiments and Design
In this study, we examine the nature of magnetohydrodynamic (MHD) Casson flow of fluid across a stretched surface in a porous material. It studies how the behaviour of Casson fluids is affected by a number of variables, including thermal radiation, chemical processes, Joule heating, and viscosity dissipation. The Keller box strategy, based on the finite difference method (FDM), is used to tackle the complex numerical problem. Graphical representations are used to show the effects of different system parts. Comprehensive tables displaying surface transfer of mass, heat, and drag rates are given for your convenience. The study focuses on how particle motion transforms kinetic energy into heat. Increased Brownian motion leads to a higher temperature profile and a reduced concentration profile. Thicker concentration profiles are created by increased Lewis number ( ) values and rates of chemical reactions, resulting in changes in mass transfer across fluids. This in-depth investigation focuses on the complicated interactions between various variables and how they influence the Casson fluid's behaviour in the system under study.
Microstructure degradation and creep failure study of the dissimilar metal welded joint of heat-resistant steel and Inconel 617 alloy tested at 650 °C and applied stress range of 100–150 MPa
- Amit Kumar
- Krishna Guguloth
- Shailesh M. Pandey
- Sachin Sirohi
- Aleksandra Świerczyńska
- Dariusz Fydrych
- Chandan Pandey
2025 INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING
The advanced ultra-supercritical (A-USC) power plant system is anticipated to become India's next-generation base-load power station. To adopt AUSC technology, dissimilar welded joints (DWJs) between heat-resistant steels and the nickel-based alloys, using the nickel-based fillers, will need to be implemented. However, failure of dissimilar welded joints from P92 steel base metal or the heat affected zone (HAZ) has been commonly observed under high-temperature creep conditions. In the present study, the creep rupture behaviours and rupture mechanisms of DWJ between the Ni-based alloy Inconel 617 and heat-resistant P92 steel with Inconel 617 (ERNiCrCoMo-1) filler metal were investigated. Creep tests were conducted at 650 °C in the stress range of 100–150 MPa. To examine the creep rupture behaviour of the DWJ samples, optical microscopy (OM), scanning electron microscopy (SEM) and microhardness tests were performed. Cross-sectional images of the fractured creep specimens tested under various operating conditions revealed failures originating from distinct locations, including the P92 base metal and the inter-critical heat affected zone (HAZ). The specimen tested at 650 °C/150 MPa exhibited failure originating from the P92 base metal, whereas the specimen tested at 650 °C under the stress range of 100–130 MPa showed failure from the inter-critical heat affected zone (ICHAZ). The specimens tested at 650 °C/100–130 MPa, which failed from the ICHAZ, exhibited a typical Type IV inter-granular failure. This failure mode is primarily attributed to matrix softening in HAZ, weakening of the boundaries, coarsening of the precipitates, and the evolution of intermetallic Laves phases. The specimen that failed in the stress range of 100–130 MPa exhibited a high density of microvoids in the ICHAZ, along with a few microvoids in the FGHAZ. The weld metal showed negligible degradation in microstructure, while the hardness study revealed a significant increase in hardness with an increase in rupture time, i.e., a decrease in applied stress and it was attributed to evolution of the new carbide phases in weld metal. The ICHAZ and FGHAZ confirmed the formation of fine prior austenite grain boundaries (PAGBs) during the welding thermal cycle, which exhibited a lower density of carbide precipitates and this played a major role in Type IV failure.
Mobile mutual-visibility sets in graphs
- Magdalena Lemańska
- Magda Dettlaff
- Juan Alberto Rodriguez-Velazquez
- Ismael Gonzalez Yero
2025 ARS Mathematica Contemporanea
Given a connected graph G, the mutual-visibility number of G is the cardinality of a largest set S such that for every pair of vertices x, y ∈ S there exists a shortest x, y-path whose interior vertices are not contained in S. Assume that a robot is assigned to each vertex of the set S. At each stage, one robot can move to a neighbouring vertex. Then S is a mobile mutual-visibility set of G if there exists a sequence of moves of the robots such that all the vertices of G are visited while maintaining the mutual-visibility property at all times. The mobile mutual-visibility number of G, denoted Mobμ(G), is the cardinality of a largest mobile mutual-visibility set of G. In this paper we introduce the concept of the mobile mutual-visibility number of a graph. We begin with some basic properties of the mobile mutual-visibility number of G and its relationship with the mutual-visibility number of G. We give exact values of Mobμ(G) for particular classes of graphs, i.e. cycles, wheels, complete bipartite graphs, and block graphs (in particular trees). Moreover, we present bounds for the lexicographic product of two graphs and show characterizations of the graphs achieving the limit values of some of these bounds. As a consequence of this study, we deduce that the decision problem concerning finding the mobile mutual-visibility number is NP-hard. Finally, we focus our attention on the mobile mutual-visibility number of line graphs of complete graphs, prism graphs and strong grids of two paths.
Modeling of microstructure evolution during high-temperature oxidation of porous Fe-Cr steels
- Samih Haj Ibrahim
- Damian Koszelow
- Małgorzata Makowska
- Sebastian Molin
2025 MATERIALS & DESIGN
Research on the high-temperature oxidation of metals and alloys is experimentally challenging due to the requirement for long-term corrosion exposure, and in the case of porous alloys, due to their complex internal microstructure. In this study, a corrosion model based on the morphological operations of dilation and erosion has been developed. This approach allows for a utilization of various raster representations of the microstructure as input to investigate the microstructure evolution of porous alloys during the corrosion process. Herein, porous microstructures of the porous Fe-Cr steels obtained from SEM imaging, X-ray tomography, and artificial 3D models generated with the use of Generative Adversarial Networks were used as test cases. The obtained results demonstrated high compliance with the experimental evaluation of porosity evolution and chromium content decrease during oxidation at 700 °C for 3000 h. Additionally, new material microstructures were studied and the influence of initial porosity on the chromium content depletion and alloy lifetime during long-term oxidation was revealed.
Modeling the effect of external load variations on single, serie and parallel connected microbial fuel cells
- Szymon Potrykus
- Janusz Nieznański
- Filip Kutt
- Francisco-Jesus Fernandez-Morales
2025 BIORESOURCE TECHNOLOGY
This paper presents a microbial fuel cell (MFC) model designed to analyze the effect of the external load on MFC performance. The model takes into account the voltage and the chemical oxygen demand (COD) dependence on the external load. The value of the model parameters were calibrated by means of the voltage relaxation method tests using a controlled load current. Laboratory measurements and MATLAB Simulink model computations were used to validate the proposed model. The tests results demonstrated that the proposed model accurately predicts the voltage and COD evolution during the batch cycle of the MFC. The root mean square error (RMSE) was used to assess the fitting goodness of the model. The RMSE of COD and voltage generation was in all the cases lower than 4%, predicting accurately the behaviour of single MFC as well as MFC connected in series or parallel.
Monitoring of absorptive model biogas purification process using sensor matrices and gas chromatography
- Edyta Słupek
- Dominik Dobrzyniewski
- Patrycja Makoś-Chełstowska
- Bartosz Szulczyński
- Jacek Gębicki
2025 MEASUREMENT
This study examined the process of purifying model biogas using a new type of absorbent based on a Deep Eutectic Solvent (DES) and a commercially available absorbent (Genosorb) to remove acetone, toluene, and cyclohexane. The main aim of the research was to control the purification efficiency using gas chromatography (GC) and an alternative method based on sensor matrices (SM). As a result of comparing the multidimensional SM signals with the GC result, the lowest difference between SM and GC (3.69%) was achieved with the DES. When using Genosorb, the differences between the methods were slightly more pronounced, reaching 10.26%. The studies also confirmed that SM results showed significant agreement, accuracy, precision, and equivalence compared to GC results. Nowadays, the literature has not reported this issue. The presented research fills the current gap in the literature and contributes to the development of knowledge in the practical application of SM.
Multimodal Augmented Reality System for Real-Time Roof Type Recognition and Visualization on Mobile Devices
- Bartosz Kubicki
- Artur Janowski
- Adam Inglot
2025 Applied Sciences-Basel
The utilization of augmented reality (AR) is becoming increasingly prevalent in the integration of virtual reality (VR) elements into the tangible reality of the physical world. It facilitates a more straightforward comprehension of the interconnections, interdependencies, and spatial context of data. Furthermore, the presentation of analyses and the combination of spatial data with annotated data are facilitated. This is particularly evident in the context of mobile applications, where the combination of real-world and virtual imagery facilitates enhances visualization. This paper presents a proposal for the development of a multimodal system that is capable of identifying roof types in real time and visualizing them in AR on mobile devices. The current approach to roof identification is based on data made available by public administrations in an open-source format, including orthophotos and building contours. Existing computer processing technologies have been employed to generate objects representing the shapes of building masses, and in particular, the shape of roofs, in three-dimensional (3D) space. The system integrates real-time data obtained from multiple sources and is based on a mobile application that enables the precise positioning and detection of the recipient’s viewing direction (pose estimation) in real time. The data were integrated and processed in a Docker container system, which ensured the scalability and security of the solution. The multimodality of the system is designed to enhance the user’s perception of the space and facilitate a more nuanced interpretation of its intricacies. In its present iteration, the system facilitates the extraction and classification/generalization of two categories of roof types (gable and other) from aerial imagery through the utilization of deep learning methodologies. The outcomes achieved suggest considerable promise for the advancement and deployment of the system in domains pertaining to architecture, urban planning, and civil engineering.
MXene-based materials as adsorbents, photocatalysts, membranes and sensors for detection and removal of emerging and gaseous pollutants: A comprehensive review
- Mohammad Hadi Dehghani
- Nadeem Hussain Solangi
- Nabisab Mujawar Mubarak
- Natarajan Rajamohan
- Subrajit Bosu
- Amina Othmani
- Md. Ahmaruzzaman
- Soumya Ranjan Mishra
- Baishali Bhattacharjee
- Vishal Gadore
- Talib Hussain Banglani
- Nawab Waris
- Ali Hyder
- Ayaz Ali Memon
- Khalid Hussain Thebo
- Payal Joshi
- Grzegorz Boczkaj
- Rama Rao Karri
2025 Pełny tekst Arabian Journal of Chemistry
2D materials have garnered significant attention as potential solutions to various environmental challenges. Graphene, molybdenum disulfide, MXenes, and boron nitride have emerged as the most popular candidates among these materials. This article presents a comprehensive review and discussion on the emerging applications of MXenes in environmental engineering. MXenes have demonstrated immense potential as future materials for adsorption purposes. They have proven to be highly effective in removing emerging pollutants (heavy metals and organic pollutants) through the adsorption phenomenon. The effectiveness of MXenes in removing lead (Pb2+), chromium (Cr6+), copper (Cu2+), uranium (U6+), and mercury (Hg2+) has been confirmed, with a sorption capacity ranging from 100 to 250 mg g−1. Furthermore, MXenes have effectively removed several radionuclides, including uranium, europium, strontium, barium, and thorium. MXenes have proven to be highly efficient in treating water through adsorption in emerging organic pollutants, even for various organic dyes such as methylene blue, acid blue, congo red, methyl orange, and rhodamine B (RhB). Additionally, MXenes exhibit high treatment performance in adsorbing several pharmaceuticals like cloxacillin (CLX), ampicillin (AMP), amoxicillin (AMX), ciprofloxacin (CPX), amitriptyline (AMT), verapamil (VRP), carbamazepine (CBM), 17 α-ethinyl estradiol, ibuprofen (IBP), and diclofenac (DCF). Overall, MXenes offer several advantages, such as good conductivity, thermal performance, high surface area, and selectivity of intermolecular interactions. However, their application requires thoroughly evaluating their environmental impact and life cycle assessment.
Nano-adsorbent Modification by Deep Eutectic Solvents for Wastewater Treatment Applications
- Amir Asadi
- Grzegorz Boczkaj
- Elaheh Kowsari
- Seeram Ramakrishna
2025
The Greek “εύ” and “τήξις” term is the root of the “eutectic” word that refers to the low melting of mixture. Generally, an eutectic solvent depicts a mixture of components (at least one is in solid phase) that under particular ratios weak molecular interactions allow to obtain a mixture having melting point at a much lower temperature than that of each component (García-Álvarez 2019). Although A. P. Abbott et al. discovered the deep eutectic solvents and provided the fundamental study of DESs, the prominent eutectic mixtures such as honey and syrup have been used in daily life for ages. As it is already known, DESs consist of at least two components that can provide hydrogen-bond interactions (Abbott et al. 2003).
Net-zero policy and forward default risk in the energy sector:Evidence of corporate environmentalism using (a)symmetricmodels
- Muhammad Mushafiq
- Błażej Prusak
- Nicholas Apergis
2025 Business Strategy and the Environment
This study aims to examine the impact of the net-zero policy on forward default risk atthe firm level within the energy sector of the US, spanning over the period 2007–2021.The research employs Panel Vector Autoregression (PVAR) modeling, as well as linearand non-linear Autoregressive Distributed Lag (ARDL) models to investigate this rela-tionship. The findings suggest that the implementation of net-zero policy measures canhave complex effects on firms' default risk in both the short and long run. The PVARresults confirm a unidirectional negative impact of net-zero policies on forward defaultrisk over 2, 3, and 5 years. The symmetric ARDL model results show a negative long-runimpact on the future probability of default, with short-run impacts being positive acrossall time horizons. The asymmetric ARDL model findings indicate that positive net-zeromeasures reduce the probability of default in the long run and increase it in the shortrun across all time horizons. Conversely, negative shocks of net-zero measures lead toan increase in the forward probability of default in the long run. The differences in find-ings between the long and short run are attributed to the effects of capital expenditureson infrastructure expenses required to achieve net-zero results. This study contributesto the literature on financial outcomes and the impact of adopting sustainable develop-ment and net-zero goals. The policy implications suggest that a supportive institutionalframework must be provided to reduce the financial default in energy sector firms,which will assist in capital and infrastructure expenditures in the short run.
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).
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.