Repozytorium publikacji - Politechnika Gdańska

Ustawienia strony

english
Repozytorium publikacji
Politechniki Gdańskiej

Pokaż publikacje z roku

Ostatnie pozycje

  • High resolution optical and acoustic remote sensing datasets of the Puck Lagoon
    • Lukasz Janowski
    • Dimitrios Skarlatos
    • Panagiotis Agrafiotis
    • Paweł Tysiąc
    • Andrzej Pydyn
    • Mateusz Popek
    • Anna M. Kotarba-Morley
    • Gottfried Mandlburger
    • Łukasz Gajewski
    • Mateusz Kolakowski
    • Alexandra Papadaki
    • Juliusz Gajewski
    2024 Pełny tekst Scientific Data

    The very shallow marine basin of Puck Lagoon in the southern Baltic Sea, on the Northern coast of Poland, hosts valuable benthic habitats and cultural heritage sites. These include, among others, protected Zostera marina meadows, one of the Baltic’s major medieval harbours, a ship graveyard, and likely other submerged features that are yet to be discovered. Prior to this project, no comprehensive high-resolution remote sensing data were available for this area. This article describes the first Digital Elevation Models (DEMs) derived from a combination of airborne bathymetric LiDAR, multibeam echosounder, airborne photogrammetry and satellite imagery. These datasets also include multibeam echosounder backscatter and LiDAR intensity, allowing determination of the character and properties of the seafloor. Combined, these datasets are a vital resource for assessing and understanding seafloor morphology, benthic habitats, cultural heritage, and submerged landscapes. Given the significance of Puck Lagoon’s hydrographical, ecological, geological, and archaeological environs, the high-resolution bathymetry, acquired by our project, can provide the foundation for sustainable management and informed decision-making for this area of interest.

  • Higher harmonics of the intensity modulated Photocurrent/Photovoltage spectroscopy response - a tool for studying photoelectrochemical nonlinearities
    • Adrian Olejnik
    • Katarzyna Grochowska
    2024 Pełny tekst MEASUREMENT

    In this work, a higher harmonic analysis (HHA) of the intensity modulated photocurrent/photovoltage (IMPS/IMVS) spectroscopy data is proposed as a potent tool for studying nonlinear phenomena in photoelectrochemical and photovoltaic systems. Analytical solutions of kinetic equations were constructed for cases of single and double resonance accounting for various sources of higher harmonics. These sources correspond to the physical sources of nonlinear effects in the response including intensity-dependent generation current, intensity-dependent recombination, and second-order recombination. Due to the fact that the solutions for those cases are different, a qualitative methodology for analysis of harmonics is proposed. The methodology is illustrated by two experimental examples – Si photodiode for IMVS and TiO2 nanotubes for IMPS. It was capable of distinguishing second order recombination in the first case and intensity-dependent transport rate for the latter.

  • Highly Integrable Planar-structured Printed Circularly Polarized Antenna for Emerging Wideband Internet of Things Applications in the Millimeter-Wave Band
    • Ullah Ubaid
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2024 Pełny tekst Scientific Reports

    This paper proposes a numerically and experimentally validated printed wideband antenna with a planar geometry for Internet of Things (IoT) applications. This design tackles the challenges associated with deploying IoT sensors in remote areas or across extensive geographical regions. The proposed design exploits a coplanar-waveguide-fed modified microstrip line monopole for excitation of circularly polarized waves radiating in the broadside direction. The primary design is based on perturbations of the microstrip line protracted from a grounded coplanar waveguide. The capacitively coupled short rectangular stubs are periodically inserted alternately and excited asymmetrically on each side of the microstrip line parallel to the direction of the electric field vector. The sequential phase excitation of the periodic stubs generates a rectangular-cascaded electric field, which suppresses the stop band at the open end. As a result, the antenna radiates in the broadside direction. The impedance bandwidth of the antenna exceeds 8 GHz in the 28 GHz mm-wave band, i.e., it ranged from 25 GHz to 33.5 GHz. Additionally, an axial ratio below 3 dB is achieved within the operating band from 26 GHz to 33.5 GHz with the alterations of the surface current using straightforward topological adjustments of the physical parameters. The average in-band realized gain of the antenna is 10 dBic when measured in the broadside direction. These results indicate that the proposed design has the potential to improve the connectivity between IoT devices and the constantly varying orientation of satellites by mitigating the polarization mismatch.

  • Highly sensitive microwave sensors based on open complementary square split-ring resonator for sensing liquid materials
    • Chandu Ds
    • K.B.S. Sri Nagini
    • Rusan Kumar Barik
    • Sławomir Kozieł
    2024 Pełny tekst SENSORS

    This paper presents high-sensitivity sensors based on open complementary square split-ring resonator and modified open complementary split-ring resonator operating at 4.5 GHz and 3.4 GHz, respectively. The sensors are designed for the detection of multiple liquid materials, including distilled water, methanol, and ethanol. The liquid under test is filled in a glass container loaded using a pipette. Compared to the conventional OCSSRR, the modified OCSSRR with multiple rings exhibits a higher frequency shift of 1200 MHz, 1270 MHz, and 1520 MHz for ethanol, methanol, and distilled water, respectively. The modified sensor also demonstrates a high sensitivity of 308 MHz/RIU for ethanol concentration which is the highest among the existing microwave sensors. The sensors in this manuscript are suitable for multiple liquid material sensing applications.

  • Highly-Compact Dual-Band Bandpass Waveguide Filter Based on Cross-Shaped Frequency-Dependent Coupling
    • Lubina Irum
    • Muhammad Yameen Sandhu
    • Adam Lamęcki
    • Roberto Gomez-Garcia
    • Michał Mrozowski
    2024

    This work reports the design of an original class of highly-compact dual-band bandpass filter based on dual-mode waveguide resonators inter-coupled through a novel type of frequency-dependent coupling (FDC). The devised FDC consists of a cross-shaped metallic structure placed in the broad wall of a rectangular waveguide. This FDC produces two additional poles and three extra transmission zeros (TZs). Specifically, each pole is surrounded by a pair of TZs, thus generating a dual-band bandpass filtering response. An equivalent lumped-element circuit model of the proposed FDC is provided to facilitate the filter synthesis process. For validation purposes, electromagnetic-(EM)-simulation results for a third-order dual-band bandpass filter design made up of two dual-mode rectangular waveguide resonators inter-coupled with a cross-shaped FDC are presented.

  • Highly-Miniaturized Microfluidically-Based Frequency Reconfigurable Antenna Diplexer Employing Half-Mode SIRW
    • Rusan Kumar Barik
    • Sławomir Kozieł
    2024 AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS

    This article introduces a super-miniaturized frequency reconfigurable antenna diplexer based on microfluidic techniques. The proposed structure is developed using a half-mode substrate-integrated rectangular waveguide (HMSIRW). The antenna architecture consists of two HMSIRW cavities loaded with L-shaped slots, which are excited by two microstrip feedlines to realize two distinct radiating frequency bands. The footprint of the antenna diplexer is miniaturized by using the half-mode cavities. Further size reduction is achieved by the capacitive loading of the slots. The design evaluation, radiation mechanism, parametric analysis, and equivalent circuit model are discussed in detail. The empty fluidic vias are drilled on the bottom plane of the cavities and poured with various dielectric liquids to obtain independent frequency reconfigurability at two operating bands. For validation, a frequency reconfigurable antenna diplexer is designed, manufactured, and demonstrated experimentally. The measured results show that the return loss, isolation, and realized gains are greater than –20 dB, 28 dB, and 3.3 dBi, respectively, while ensuring small footprint of only 0.071λg2. The fabricated diplexer exhibits a frequency reconfiguration range greater than 17% at both frequency bands.

  • High-performance activation of ozone by sonocavitation for BTEX degradation in water
    • Kirill Fedorov
    • Lingshuai Kong
    • Chongqing Wang
    • Grzegorz Boczkaj
    2024 Pełny tekst JOURNAL OF ENVIRONMENTAL MANAGEMENT

    This work presents a novel advanced oxidation process (AOP) for degradation of emerging organic pollutants – benzene, toluene, ethylbenzene and xylenes (BTEXs) in water. A comparative study was performed for sonocavitation assisted ozonation under 40–120 kHz and 80–200 kHz dual frequency ultrasounds (DFUS). Based on the obtained results, the combination of 40–120 kHz i.e., low-frequency US (LFDUS) with O3 exhibited excellent oxidation capacity degrading 99.37–99.69% of BTEXs in 40 min, while 86.09–91.76% of BTEX degradation was achieved after 60 min in 80–200 kHz i.e., high-frequency US (HFDUS) combined with O3. The synergistic indexes determined using degradation rate constants were found as 7.86 and 2.9 for LFDUS/O3 and HFDUS/O3 processes, respectively. The higher extend of BTEX degradation in both processes was observed at pH 6.5 and 10. Among the reactive oxygen species (ROSs), hydroxyl radicals (HO•) were found predominant according to scavenging tests, singlet oxygen also importantly contributed in degradation, while O2•- radicals had a minor contribution. Sulfate (SO42−) ions demonstrated higher inhibitory effect compared to chloride (Cl−) and carbonate (CO32−) ions in both processes. Degradation pathways of BTEX was proposed based on the intermediates identified using GC-MS technique.

  • High-Performance Machine-Learning-Based Calibration of Low-Cost Nitrogen Dioxide Sensor Using Environmental Parameter Differentials and Global Data Scaling
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    • Marek Wójcikowski
    • Bogdan Pankiewicz
    2024 Pełny tekst Scientific Reports

    Accurate tracking of harmful gas concentrations is essential to swiftly and effectively execute measures that mitigate the risks linked to air pollution, specifically in reducing its impact on living conditions, the environment, and the economy. One such prevalent pollutant in urban settings is nitrogen dioxide (NO2), generated from the combustion of fossil fuels in car engines, commercial manufacturing, and food processing. Its elevated levels have adverse effects on the human respiratory system, exacerbating asthma and potentially causing various lung diseases. However, precise monitoring of NO2 requires intricate and costly equipment, prompting the need for more affordable yet dependable alternatives. This paper introduces a new method for reliably calibrating cost-effective NO2 sensors by integrating machine learning with neural network surrogates, global data scaling, and an expanded set of correction model inputs. These inputs encompass differentials of environmental parameters (such as temperature, humidity, atmospheric pressure), as well as readings from both primary and supplementary low-cost NO2 detectors. The methodology was showcased using a purpose-built platform housing NO2 and environmental sensors, electronic control units, drivers, and a wireless communication module for data transmission. Comparative experiments utilized NO2 data acquired during a five-month measurement campaign in Gdansk, Poland, from three independent high-precision reference stations, and low-cost sensor data gathered by the portable measurement platforms at the same locations. The numerical experiments have been carried out using several calibration scenarios using various sets of calibration input, as well as enabling/disabling the use of differentials, global data scaling, and NO2 readings from the primary sensor. The results validate the remarkable correction quality, exhibiting a correlation coefficient exceeding 0.9 concerning reference data, with a root mean squared error (RMSE) below 3.2 µg/m3. This level of performance positions the calibrated sensor as a dependable and cost-effective alternative to expensive stationary equipment for NO2 monitoring.

  • High-speed multi-stage gas-steam turbine with flow bleeding in a novel thermodynamic cycle for decarbonizing power generation
    • Paweł Ziółkowski
    • Łukasz Witanowski
    • Piotr Klonowicz
    • Dariusz Mikielewicz
    2024 Pełny tekst RENEWABLE ENERGY

    In the global pursuit of sustainable energy and reduced carbon footprints, advances in power generation techniques play a crucial role, not only in meeting the ever-increasing energy demands but also in ensuring that environmental standards are maintained and that the health of our planet is prioritized for future generations. In the ongoing quest for sustainable energy solutions, novel high-speed multi-stage gas-steam turbine models were designed to address the challenge of decarbonized power production. The thermodynamic parameters were adopted on the basis of the negative carbon dioxide gas power plant cycle relying on the following main devices, namely: wet combustion chamber, spray-ejector condenser, sewage sludge gasifier and gas-steam turbine. The peculiarities of the present system make the turbine the link of three important devices and its parameters affect the entire thermodynamic cycle. Therefore, it is reasonable to carry out dedicated novel in literature CFD calculations that also take into account the bleeding of the medium for the gasification process. Two distinct turbine models were introduced: a two-stage turbine achieving speeds of 95 000 rpm with an efficiency of more than 80 %, and a five-stage turbine reaching 40 000 rpm with an efficiency of less than 70 %. A design assumption of a bleed pressure of 100 kPa and a mass flow rate of 0.1 kg/s was adopted for both models. Computational simulations were utilized, and the turbine stages were selected with the aim of reducing energy losses. Through this work, a significant step towards a carbon-negative future using high-speed turbine technologies was demonstrated, laying the groundwork for further advancements in the field.

  • HMSE: A tool for coupling MODFLOW and HYDRUS-1D computer programs
    • Mateusz Pawlowicz
    • Bartosz Balis
    • Adam Szymkiewicz
    • Jirka Simunek
    • Anna Gumuła-Kawęcka
    • Beata Jaworska-Szulc
    2024 Pełny tekst SoftwareX

    A new software HMSE has been developed to facilitate external coupling between two well-known programs for subsurface flow modeling: MODFLOW-2005 (saturated zone flow) and HYDRUS-1D (unsaturated zone flow). Two coupling schemes have been implemented. In the first case the groundwater recharge flux is calculated by HYDRUS-1D assuming a fixed water table position and then passed to MODFLOW input files. In the second case the water table position in HYDRUS-1D is updated periodically using the solution from MODFLOW. HMSE can be deployed in 3 modes: local, Docker and Kubernetes cluster. A web-based interface is provided to configure and run the simulation in all three cases. The software is applied to simulate groundwater table fluctuations observed in a shallow aquifer during three years.

  • Holistic collision avoidance decision support system for watchkeeping deck officers
    • Rafał Szłapczyński
    • Joanna Szłapczyńska
    • Mateusz Gil
    • Marcin Życzkowski
    • Jakub Montewka
    2024 Pełny tekst RELIABILITY ENGINEERING & SYSTEM SAFETY

    The paper presents a 3-stage synthesis-based Decision Support System for watchkeeping deck officers. Its functional scope covers conflict detection, maneuver selection, and maneuver execution, all phases supplemented by collision alerts. First, a customized elliptic ship domain is used for checking if both OS and TS will have enough free space. A survey-based navigators’ declarative OS arena is then used to determine the time at which OOW would like to take evasive action. Next, a safety level is assigned to the current situation based on the predicted violations of the ship domain and the declarative arena. The safety levels are also attributed to potential evasive maneuvers (single actions combining course alteration and rudder deflection). For a selected maneuver, Collision Avoidance Dynamic Critical Area (CADCA) is displayed, which informs OOW about the time window when the maneuver remains feasible. All of the above contribute to a holistic system of multi-level safety assessment utilizing: empirical ship domain, survey-based declarative arena, and ship dynamics-based CADCA. These, in turn, take into account navigators’ knowledge and preferences, ship maneuverability, and the impact of environmental conditions. The system is presented in three real-life scenarios located in the southern part of the Baltic Sea around the Danish straits.

  • How digital platforms support public values through government-citizen collaboration?
    • Grażyna Musiatowicz-Podbiał
    2024 Pełny tekst

    Digital platforms are becoming a popular means of multi-sided interactions between public institutions and their constituents. By enabling information sharing, consultation, and other forms of government-citizen collaboration, they facilitate co-decision-making and co-creation. Although digital platforms are not, the mechanism through which they can create public value, although important for government institutions and citizens alike, has not been systematically studied yet. This research aims at establishing a link between digital platform-based government-citizen engagement and how such engagement can generate public value. To this end, it employs the mixed method approach consisting of the systematic literature review and the analysis of 15 case studies of representative digital government platforms. The research delivers two main observations. First, digital government platforms produce three common public values: openness, government-citizen dialogue, and productivity gains. Second, unleashing the digital platforms’ public value creation potential requires infrastructural foundations, inducements for governments to engage, and mutual benefits for citizens, businesses and the government itself.

  • How digital technology affects working conditions in globally fragmented production chains: Evidence from Europe
    • Aleksandra Parteka
    • Joanna Wolszczak-Derlacz
    • Dagmara Nikulin
    2024 Pełny tekst TECHNOLOGICAL FORECASTING AND SOCIAL CHANGE

    This paper uses a sample of over 9 million workers from 22 European countries to study the intertwined relationship between digital technology, cross-border production links and working conditions. We compare the social consequences of technological change exhibited by three types of innovation: computerisation (software), automation (robots) and artificial intelligence (AI). To fully quantify work-related wellbeing, we propose a new methodology that amends the information on remuneration by reference to such non-monetary factors as the work environment (physical and social), career development prospects, or work intensity. First, we show that employee wellbeing is related to the type of technological exposure. Employees in occupations with a high degree of software or robot exposure face worse working conditions – contrary to highly AI exposed occupations. Thus, we find that AI technologies differ from previous waves of technological progress - also in relation to workers' wellbeing. Additionally, we show that the relationship between digital technology and working conditions weakly depends on participation in global production chains.

  • How does the Relationship Between the Mistakes Acceptance Component of Learning Culture and Tacit Knowledge-Sharing Drive Organizational Agility? Risk as a Moderator
    • Wioleta Kucharska
    • Tomasz Balcerowski
    • Maciej Kucharski
    • Jari Jussila
    2024 Pełny tekst

    Changes in the business context create the need to adjust organizational knowledge to new contexts to enable the organizational agile responses to secure competitiveness. Tacit knowledge is strongly contextual. This study is based on the assumption that business context determines tacit knowledge creation and acquisition, and thanks to this, the tacit knowledge-sharing processes support agility. Therefore, this study aims to expose that there is a strong link between the tacit knowledge flow across the organization and its ability to respond agilely (timely, accurately, and creatively) to contextual changes. Based on the sample composed of 640 Polish knowledge workers and data analyzed with the structural equation modeling method (SEM), this study delivers empirical evidence that tacit knowledge flow is vital for organizational agility. The obtained results confirmed that tacit knowledge sharing mediates between the mistakes acceptance component of learning culture and agility. It means agility, understood asthe ability to respond agilely to contextual changes, requires being charged by new, contextual, tacit knowledge obtained thanks to trial-error actions (learning by doing) achievable thanks to breaking conventions and experimentation. Moreover, risk management skills have been proven to be one of the critical characteristics of agile organizations today.

  • How Integration of a Brain-Machine Interface and Obstacle Detection System Can Improve Wheelchair Control via Movement Image
    • Tomasz Kocejko
    • Nikodem Matuszkiewicz
    • Jakub Kwiatkowski
    • Piotr Durawa
    • Aleksander Madajczak
    2024 Pełny tekst SENSORS

    This study presents a human-computer interaction combined with a brain-machine interface (BMI) and obstacle detection system for remote control of a wheeled robot through movement imagery, providing a potential solution for individuals facing challenges with conventional vehicle operation. The primary focus of this work is the classification of surface EEG signals related to mental activity when envisioning movement and deep relaxation states. Additionally, this work presents a system for obstacle detection based on image processing. The implemented system constitutes a complementary part of the interface. The main contributions of this work include the proposal of a modified 10–20-electrode setup suitable for motor imagery classification, the design of two convolutional neural network (CNNs) models employed to classify signals acquired from sixteen EEG channels, and the implementation of an obstacle detection system based on computer vision integrated with a brain-machine interface. The models developed in this study achieved an accuracy of 83% in classifying EEG signals. The resulting classification outcomes were subsequently utilized to control the movement of a mobile robot. Experimental trials conducted on a designated test track demonstrated real-time control of the robot. The findings indicate the feasibility of integration of the obstacle detection system for collision avoidance with the classification of motor imagery for the purpose of brain-machine interface control of vehicles. The elaborated solution could help paralyzed patients to safely control a wheelchair through EEG and effectively prevent unintended vehicle movements

  • How Sport Innovations Can Shape Sustainable Cities: An Interdisciplinary Approach
    • Narek Parsamyan
    • Aleksander Orłowski
    2024 Pełny tekst Problemy Ekorozwoju

    Leveraging the potential of sport can play a significant role in shaping cities of tomorrow, generate environmental and social change. The integration of sport into city planning can provide multiple benefits, such as promoting physical activity, health, well-being, and enhancing social cohesion. However to date, there is a lack of research on the potential of sport innovations to enhance the sustainable development of cities. This study aims to explore the role of sport innovations in sustainable cities through systematic literature review, utilizing interdisciplinary approach that combines sport and urban management disciplines to understand how sport innovations affects the sustainable living. The findings of this study identify sustainable references in sport innovations literature, including best practices for integrating sport into urban planning and development, and thus verifying their contribution to the sustainable development of cities in areas of social inclusion, community participation, collaboration and networking, organizational strategy.

  • How the Dimensions of Plant Filler Particles Affect the Oxidation-Resistant Characteristics of Polyethylene-Based Composite Materials
    • Joanna Aniśko
    • Paulina Kosmela
    • Joanna Cichocka
    • Jacek Andrzejewski
    • Mateusz Barczewski
    2024 Materials

    This study analyzed the possibility of using plant-originated waste materials (black and green tea dust) as functional polyethylene fillers. The dependence between the size of the filler particles and their antioxidant potential is discussed. Six fractions were selected: below 50 µm, 50–100 µm, 100–200 µm, 200–400 µm, 400–630 µm and 630–800 µm. Significant differences between the effect of particle size and the antioxidant properties of black and green tea were found using the extraction method to analyze antioxidant activity (DPPH method) and total phenolic content (Folin-Ciocalteu method), suggesting a higher potential for using green tea as a filler with antioxidant properties, as well as the benefits of finer active filler distribution. Biomass waste fillers were mixed with low-density polyethylene LDPE SEB 853 I’m Green®, Braskem. Those samples were oxidized at 100 °C for 5 and 15 days to investigate the radical scavenging properties of fillers in composites. Fourier transform infrared spectroscopic studies show that the addition of both types of filler prevents the thermo-oxidation of polyethylene for 5 days. After 15 days, all samples except the BTW 400–630 and 630–800 µm exhibited oxidation. The mechanical properties of the LDPE and its’ composites were tested, and we noted an increased brittleness of neat LDPE after thermal oxidation. The addition of black tea particles above 100 µm in size prevents this behavior.

  • How to make membrane distillation greener? A review on environmentally friendly and sustainable aspects
    • Emilia Gontarek-Castro
    • Roberto Castro Munoz
    2024 Pełny tekst GREEN CHEMISTRY

    There is an urgent need for the development of new water resources in order to solve the problem of the world’s growing demand for clean water. Membrane distillation (MD) is a promising alternative to conventional seawater desalination. Although MD itself is often defined as sustainable desalination technology, there are many aspects within the membrane manufacture and process operation that make it far from being green. For instance, non-biodegradable polymers, toxic solvents and fluoroalkyl silanes are typical chemicals that unfortunately are used in membrane fabrication protocols. Additionally, the huge amount of wastewater generated from membrane fabrication processes makes solvent-free methods more attractive and desired for extensive investigation. Apart from this, the low energy efficiency of MD process can be effectively overcome by integrating the MD systems with low-grade waste heat. This review critically addresses and discusses the recent advances in methods and strategies to improve the sustainability of MD technology, which is not a common scope of study among the research community. Here, our attention has been devoted to main aspects in MD membrane fabrication, such as polymers, solvents (and its costs), nonsolvents, additives, solvent-free fabrication procedures, fluoro-free post modification, and MD operation (energy consumption). This review intends to introduce inspiration for membrane scientists for the development of the next-generation MD process, by promoting the sustainable transformation of today’s approaches into a greener way. In this latter scenario, we provide some punctual considerations that could be followed by the researchers in the field.

  • Human carnosinases: A brief history, medicinal relevance, and in silico analyses
    • Klaudia Chmielewska
    • Serena Vittorio
    • Silva Gervasoni
    • Krystyna Dzierzbicka
    • Iwona Inkielewicz-Stępniak
    • Giulio Vistoli
    2024 Pełny tekst DRUG DISCOVERY TODAY

    Carnosine, an endogenous dipeptide, has been found to have a plethora of medicinal properties, such as antioxidant, antiageing, and chelating effects, but with one downside: a short half-life. Carnosinases and two hydrolytic enzymes, which remain enigmatic, are responsible for these features. Hence, here we emphasize why research is valuable for better understanding crucial concepts like ageing, neurodegradation, and cancerogenesis, given that inhibition of carnosinases might significantly prolong carnosine bioavailability and allow its further use in medicine. Herein, we explore the literature regarding carnosinases and present a short in silico analysis aimed at elucidating the possible recognition pattern between CN1 and its ligands.

  • Hyaluronic acid/tannic acid films for wound healing application
    • Marcin Wekwejt
    • Marcin Małek
    • Anna Ronowska
    • Anna Michno
    • Anna Pałubicka
    • Agnieszka Klimek
    • Beata Kaczmarek-Szczepańska
    2024 Pełny tekst INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES

    In this study, thin films based on hyaluronic acid (HA) with tannic acid (TA) were investigated in three different weight ratios (80HA/20TA, 50HA/50TA, 20HA/80TA) for their application as materials for wound healing. Surface free energy, as well as their roughness, mechanical properties, water vapor permeability rate, and antioxidant activity were determined. Moreover, their compatibility with blood and osteoblast cells was investigated. The irritation effect caused by hyaluronic acid/tannic acid films was also considered with the use of are constructed human epidermis model. The irritation effect for hyaluronic acid/tannic acid films by the in vitro method was also studied. The low surface free energy, surface roughness, and antioxidant activity presented by the obtained films were examined. All the tested compositions of hyaluronic acid/tannic acid films were hemocompatible, but only films based on 50HA/50TA were fully cytocompatible. Regarding the potential implantation, all the films except 80HA/20TA showed appropriate mechanical properties. The specimens did not exert the irritation effect during the studies involving reconstructed human epidermis.

  • Hybrid geothermal-fossil power cycle analysis in a Polish setting with a focus on off-design performance and CO2 emissions reductions
    • Kacper Szturgulewski
    • Jerzy Głuch
    • Marta Drosińska-Komor
    • Paweł Ziółkowski
    • Andrzej Gardzilewicz
    • Katarzyna Brzezińska-gołębiewska
    2024 ENERGY

    Growing demand for electricity due to economic development contributes to increased greenhouse gas production, especially CO2. However, emissions can be limited by enhancing the efficiency of primary energy conversion, such as integrating geothermal energy into coal-fired power plants. Therefore, this paper proposes replacing conventional feed-water heaters with geothermal preheaters to create a hybridized system. This study was based on a numerical model validated at a selected Polish power unit. The model was subsequently calibrated for off-design conditions to facilitate partial load analysis. The obtained characteristics outperformed those of the non-hybrid unit, generating over 18 MW of electric power output. Such an improvement could potentially boost the unit’s net efficiency by more than 2.6%. This enhancement is significant as power units typically operate under part load for approximately 90% of the time, hence the need to evaluate the performance characteristics of hybridized units in those states. Furthermore, the research outlines the potential decrease in the plant’s CO2 emission factor, with reductions reaching up to 6.5% under off-design conditions. Based on a gap analysis of the existing literature, this paper’s comprehensive partial load evaluation serves as a new addition to research on hybridized systems.

  • Hybrid Laboratory of Radio Communication With Online Simulators and Remote Access
    • Jarosław Sadowski
    • Jacek Stefański
    2024 IEEE Transactions on Education

    Contribution: Two toolsets for the remote teaching of radio communication laboratory classes: 1) online simulators for individual work of students and 2) a remote access system to laboratory workstations for group work. Initial assumptions and method of implementation of both tools are presented. Background: The COVID-19 pandemic has forced a change in teaching at all levels of education. The specificity of practical classes, such as laboratories, means that the tools used must often be atypical, prepared for a specific type of activity. Intended Outcomes: Hybrid laboratory with tools for remote learning in the form of online simulators and remote access to laboratory workstations, enabling students to achieve the same educational results in the field of radiocommunication as presential classes. Application Design: Online simulators were prepared as Javascript code run in a Web browser as part of a html page, which provide easy integration with various learning platforms and Web servers. The remote access system uses Javascript code for the user interface and a gateway server based on an Apache Web server and FastCGI interface to communicate with C/C++ programs responsible for controlling measuring equipment. Findings: Online simulators have been positively assessed by students during two years of remote learning, but comparison of the grades from remote and presential classes is inconclusive. The obtained grades were comparable in the first year of remote laboratories, but they were worse in the second year than the grades from classroom learning. The system for remote access to the laboratory stands has not yet been evaluated.

  • Hybrid use of the building as a method supporting epidemic safety
    • Rafał Janowicz
    • Wacław Szarejko
    • Marta Koperska-Kośmicka
    • Agnieszka Gębczyńska-Janowicz
    2024 Pełny tekst MEDYCYNA PRACY

    The COVID-19 pandemic has resulted in changing organisational and technical requirements in the operation of treatment facilities. This paper summarises the available knowledge on the principles of hybrid design of the architecture of treatment units to ensure that different levels of sanitary and hygienic safeguards can be implemented. The basis of this narrative overview is an analysis of the existing Polish legislation on required personnel protection measures and the European Commission’s recommendations for the long-term optimisation of building operating costs. In addition, due to the multifaceted and complex nature of the issue, the review was extended to include an example of practice in the technical adaptation of medical buildings for hybrid use in the event of a pan- demic of an aetiological agent of risk category III, as a confirmation of the postulate regarding the need to modify the guidelines for the architectural design of the space of medical units, particularly those involved in the care of the elderly.

  • Hybridized PWM Strategy for Three- and Multiphase Three-Level NPC Inverters
    • Arkadiusz Lewicki
    • Dmytro Kondratenko
    • Charles Odeh
    2024 Pełny tekst IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS

    A simple hybridized pulsewidth modulation (PWM) algorithm for three- and multiphase three-level neutral point clamped (NPC) inverters is proposed. The proposed solution is based on classical space vector PWM (SVPWM) algorithms for two-level inverters but can also be based on sinusoidal PWM with min–max injection. An additional level of output voltage is obtained by modifying the resulting switching patterns taking into account the actual dc-link voltages. In the case of SVPWM algorithms, such an approach eliminates the need to find the subsector where the reference voltage vector is located. It is also not necessary to analyze the changes in the position and length of active vectors in the case of dc-link voltage imbalance. DC-link voltage balancing is achieved by modifying the switching pattern, taking into account the values and direction of phase currents and actual dc-link voltages. Also, the algorithm optimizes the switching pattern and eliminates unnecessary switching instances. The proposed approach utilizes both space vector analysis and independent control of individual inverter-legs. The latter is peculiar to carrier-based PWM; hence, the proposed solution is termed hybridized PWM. Presented experimental tests and results validated the proposed control concept and algorithm for three- and multiphase NPC inverters

  • Hybridized SVPWM Algorithm for Multilevel CHB Inverter With DC-Link Voltage Control Capability
    • Arkadiusz Lewicki
    • Charles Odeh
    • Marcin Morawiec
    2024 IEEE TRANSACTIONS ON POWER ELECTRONICS

    The deployment of a space vector pulsewidth modulation (SVPWM) scheme in controlling cascaded H-bridge multilevel inverter (CHB MLI) is quite challenging; especially, when a substantial number of output voltage levels are involved and the dc-link voltages are out of balance. In this article, a simple SVPWM algorithm for CHB MLI is proposed. In the proposed algorithm, all the H-bridges in an inverter phase are treated as a single H-bridge. Consequently, the CHB MLI can be treated as a three-level cascaded H-bridge (CHB) inverter, regardless of the number of series-connected H-bridges. This approach simplifies the construction of the space vector diagram even in dc-link voltage imbalance scenarios. The proposed voltage balancing strategy is based on two approaches: interphase balancing and energy exchange between H-bridges in a phase of the CHB MLI. The former is realized by the appropriate selection of active vectors for an equivalent three-level CHB inverter. The latter is realized through the appropriate distribution of duty factors, determined in the first step of the algorithm; their unity or zero values operate the H-bridges in actively connected or bypassed modes in view of commutation losses reduction. Simulation and experimental results are presented for the authentication of the proposed algorithm on a seven-level CHB MLI.

  • Hydration of N-Hydroxyurea from Ab Initio Molecular Dynamics Simulations
    • Mateusz Balicki
    • Maciej Śmiechowski
    2024 Pełny tekst MOLECULES

    N-Hydroxyurea (HU) is an important chemotherapeutic agent used as a first-line treatment in conditions such as sickle cell disease and β-thalassemia, among others. To date, its properties as a hydrated molecule in the blood plasma or cytoplasm are dramatically understudied, although they may be crucial to the binding of HU to the radical catalytic site of ribonucleotide reductase, its molecular target. The purpose of this work is the comprehensive exploration of HU hydration. The topic is studied using AIMD simulations that apply a first principles representation of the electron density of the system. This allows for the calculation of infrared spectra, which may be decomposed spatially to better capture the signatures of solute–solvent interactions. The studied molecule is found to be strongly hydrated and tightly bound to the first shell water molecules. The analysis of the distance-dependent spectra of HU shows that the E and Z conformers spectrally affect 3.4 and 2.5 of the closest H2O molecules, in spheres of radii of 3.7 Å and 3.5 Å, respectively. The distance-dependent spectra corresponding to these cutoff radii show increased absorbance in the red-shifted part of the water OH stretching vibration band, indicating local enhancement of the hydrogen bond network. The radially resolved IR spectra also demonstrate that HU effortlessly incorporates into the hydrogen bond network of water and has an enhancing effect on this network. Metadynamics simulations based on AIMD methodology provide a picture of the conformational equilibria of HU in solution. Contrary to previous investigations of an isolated HU molecule in the gas phase, the Z conformer of HU is found here to be more stable by 17.4 kJ·mol−1 than the E conformer, pointing at the crucial role that hydration plays in determining the conformational stability of solutes. The potential energy surface for the OH group rotation in HU indicates that there is no intramolecular hydrogen bond in Z-HU in water, in stark contrast to the isolated solute in the gas phase. Instead, the preferred orientation of the hydroxyl group is perpendicular to the molecular plane of the solute. In view of the known chaotropic effect of urea and its N-alkyl-substituted derivatives, HU emerges as a unique urea derivative that exhibits a kosmotropic ordering of nearby water. This property may be of crucial importance for its binding to the catalytic site of ribonucleotide reductase with a displacement of a water molecule.

  • Hydraulic valve design methodology for hydro turbine control system
    • Mateusz Kosek
    • Paweł Śliwiński
    • Dariusz Downar
    2024 Pełny tekst FLOW MEASUREMENT AND INSTRUMENTATION

    The control of the turbine and its equipment in a hydroelectric power plant requires the HPU (hydraulic power unit) to deliver large volumes of working fluid in a short time at specific optimum control parameters. The use of typical proportional flow control valves created by manufacturers of hydraulic components in low-pressure control systems is disadvantageous due to high pressure losses in the control chambers. This paper presents the methodology and test results while designing a hydraulic proportional valve for low pressure and high flow rate operation. CFD (computational fluid dynamics) theory was analyzed and characteristic values were determined. The validation of CFD tests through those on the test bench was carried out, correction factor was determined. A new proprietary solution was developed and a series of simulation studies were carried out to determine the flow characteristics depending on the degree of the opening of the proportional flow control valve.

  • Hydrochars as a bio-based adsorbent for heavy metals removal: A review of production processes, adsorption mechanisms, kinetic models, regeneration and reusability of hydrochar
    • Aisha Khanzada
    • Hussein Al-Hazmi
    • Tonni Agustiono Kurniawan
    • Joanna Majtacz
    • Grzegorz Piechota
    • Gopalakrishnan Kumar
    • Peyman Ezzati
    • Mohammad Saeb
    • Navid Rabiee
    • Hassan Karimi-Maleh
    • Eder C. Lima
    • Jacek Mąkinia
    2024 SCIENCE OF THE TOTAL ENVIRONMENT

    The spread of heavy metals throughout the ecosystem has extremely endangered human health, animals, plants, and natural resources. Hydrochar has emerged as a promising adsorbent for removing heavy metals from water and wastewater. Hydrochar, obtained from hydrothermal carbonization of biomass, owns unique physical and chemical properties that are highly potent in capturing heavy metals via surface complexation, electrostatic interactions, and ion exchange mechanisms. This review focuses on removing heavy metals by hydrochar adsorbents from water bodies. The article discusses factors affecting the adsorption capacity of hydrochars, such as contact time, pH, initial metal concentration, temperature, and competing ions. Literature on optimization approaches such as surface modification, composite development, and hybrid systems are reviewed to enlighten mechanisms undertaking the efficiency of hydrochars in heavy metals removal from wastewater. The review also addresses challenges such as hydrochar regeneration and reusability, alongside potential issues related to its disposal and metal leaching. Integration with current water purification methods and the significance of ongoing research and initiatives promoting hydrochar-based technologies were also outlined. The article concludes that combining hydrochar with modern technologies such as nanotechnology and advanced oxidation techniques holds promise for improving heavy metal remediation. Overall, this comprehensive analysis provides valuable insights to guide future studies and foster the development of effective, affordable, and environmentally friendly heavy metal removal technologies to ensure the attainment of safer drinking water for communities worldwide.

  • Hydrogen and chalcogen bonds in crystals of chalcogenadiazolecarboxylic acids – competition or cooperation?
    • Jan Alfuth
    • Agnieszka Czapik
    • Beata Zadykowicz
    • Teresa Olszewska
    2024 CRYSTENGCOMM

    This article presents crystal structures of chalcogenadiazolecarboxylic acids bearing both a hydrogen and a chalcogen bond donor. The selected molecules varied in the size of the aromatic unit, the chalcogen atom and/or the position of the carboxyl group in the core structure. The most common synthons in their lattice are "R" _"2" ^"2" (8) self-complementary acid dimers or four-membered [Ch···N]2 rings. Supramolecular synthons where chalcogenadiazole moieties interact with the carboxyl group were also identified. Both ESP calculations and experimental data showed that all the studied molecules adopted flat conformations, but only in the case of three crystal structures were flat sheets observed. To assess the contribution of hydrogen and chalcogen bonds to the stabilization of the crystal structure, crystal lattice energy calculations were performed.

  • Hydrogen direct reduction and reoxidation behaviour of high-grade pellets
    • Pasquale Cavaliere
    • Leandro Dijon
    • Aleksandra Laska
    • Damian Koszelow
    2024 Pełny tekst INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

    High grade pellets with basicity index close to 0.5 were directly reduced in pure hydrogen atmosphere. The reduction experiments were performed in the temperature range 800 e1000 C at the pressure of 8 bar. The pellets internal structure was analysed through micro tomography observations in the unreduced and reduced conditions. After reduction, the pellets showed a variation of porosity up to more than 15% with a remarkable change in the pore dimensions and aspect. Given the pores aspect variations, tortuosity strongly varied. This is believed to have large influence on the pellets reduction kinetics depending on the reduction conditions. After reduction, the pellets were re-oxidized in the temperature range 200e700 C for different times. Up to 500 C the weight increase due to oxidation resulted very slow, for higher temperatures the re-oxidation behaviour showed a very remarkable acceleration.

  • Hydrogen evolution reaction catalyzed by Co-based metal-organic frameworks and their derivatives
    • Natalia Łukasik
    • Daria Roda
    • Maria Alaide de Oliveira
    • Bráulio Silva Barros
    • Joanna Kulesza
    • Marcin Łapiński
    • Hanna Świątek
    • Anna Ilnicka
    • Tomasz Klimczuk
    • Mariusz Szkoda
    2024 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

    In this study, Co-bearing Metal-Organic Frameworks (MOFs) are grown via a facile solvothermal process on the surface of two kinds of conductive substrates – titanium dioxide nanotubes (TiO2NT) and fluorine-doped tin oxide (FTO) glass and tested as electrodes in the electrochemical hydrogen evolution reaction (HER). The materials derived from three organic linkers - terephthalic acid (Co-BDC), 2-aminoterephthalic acid (Co-BDCNH2), and trimesic acid (Co-BTC) are characterized by FTIR, Raman, XRD, SEM-EDS, BET, and XPS. Among the layers on FTO without post-synthesis treatment, Co-BTC shows the highest activity (overpotential of HER 1.72 V vs. Ag/AgCl/KCl). The effects of substrate change on TiO2NT and annealing of Co-BTC layers in air and argon on their electrocatalytic properties are also studied. Using TiO2 nanotubes as a substrate and annealing the material in air results in a reduction of the hydrogen evolution overpotential to 1.44 V vs. Ag/AgCl/KCl and a significant reduction in the exchange current density.

  • Hydrogen fuel cell power supply for hybrid elelectric multiple unit train
    • Aleksander Jakubowski
    • Lech Lipiński
    • Dawid Kwiatkowski
    • Dariusz Karkosiński
    • Natalia Karkosińska-Brzozowska
    2024 Archives of Electrical Engineering

    In European countries, electrified routes amount for 40% to 65% of the total railway networks length. Some of those routes are only partially electrified, and construction of a catenary network might not be viable on all routes. Consequently, operators run diesel trains under catenary or require both an electric and diesel vehicle, increasing costs of operation. Dual-mode vehicles exist, but they are mostly equipped with diesel generators, adding to the pollution and resulting in reduced movement dynamics. In this article, the authors present a hydrogen-hybrid electric multiple unit (HEMU), as an environmentally friendly vehicle for partially electrified railway lines. Insight into technologies utilized by both hybrid and hydrogen rail vehicles based on the literature review allowed for the formulation of requirements for such a vehicle. Furthermore, an approach to a modelling hybrid vehicle is described, including an energy management algorithm. A series of simulations were conducted, showing an operation of an HEMU on a partially electrified suburban/regional route. The presented simulation results show potential for the future introduction of hydrogen hybrid electric multiple units as a viable solution for partially electrified local and regional routes.

  • Hydroxyl and sulfate radical-based degradation of ciprofloxacin using UV-C and/or Fe2+-catalyzed peroxymonosulfate: Effects of process parameters and toxicity evaluation
    • Jibran Iqbal
    • Noor S. Shah
    • Javed Ali Khan
    • Kifayatullah Khan
    • Muhammad Wakeel
    • Heba Taha M. Abdelghani
    • Zia Ul Haq Khan
    • Grzegorz Boczkaj
    2024 JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY

    Ciprofloxacin (CIP) is a valuable antibiotic and discharged in huge quantities in aquatic environment. Different •OH and SO4•−-based advanced oxidation technologies (AOTs), e.g., Fe2+/PMS, UV-C/PMS, and UV-C/Fe2+/PMS are developed for treatment of CIP. The removal of CIP by Fe2+/PMS, UV-C/PMS and UV-C/Fe2+/PMS was 63, 77, and 87 %, respectively, under identical conditions which showed better performance of UV-C/Fe2+/PMS. The UV-C/Fe2+/PMS also caused high removal of total organic carbon of CIP. This high performance of UV-C/Fe2+/PMS-based AOTs possibly looked due to dual activation of PMS by UV-C and Fe2+. The removal of CIP by the three AOTs was found due to •OH and SO4•− and the later showed high reactivities with CIP, i.e., 2.45 109 and 2.35 109 M−1 s−1, respectively. The study of factors affecting the reactivities and/or yield of •OH and SO4•− diminished CIP degradation efficiency. The change in pH of solution and temperature and doses of Fe2+, PMS, and CIP exhibited significant impacts on the removal of CIP. The addition of inorganic ions showed strong inhibiting effects of NO2–, CO32–, and HCO3– while Cu2+ showed facilitating role. Analysis of degradation of CIP by GC–MS was used to develop proposed pathways. Acute and chronic toxicities of CIP and its products were measured by ECOSAR program and showed the resulting products to be non-toxic.

  • Hyperbaric Storage at Subzero Temperature – the Effect on the Shelf-Life and Selected Quality Characteristics of Raw Pork Sausages
    • Edyta Malinowska-Pańczyk
    • Katarzyna Mazur
    2024 Pełny tekst Polish Journal of Food and Nutrition Sciences

    The aim of this study was to determine the microbiological stability and changes occurring in selected physicochemical properties of raw pork sausages during hyperbaric storage at subzero temperature (HS-ST). It was shown that storage at moderate pressures (up to 111 MPa) led to a reduction in microbial populations. After 21 days of storage under these conditions, no microorganisms were detected in the samples. Additionally, the inhibition of thiobarbituric acid reactive substance (TBARS) formation was observed under HS-ST conditions. The negative effect of the storage at 111 MPa/−10℃ was the sausage colour change from pink to grey-pink or grey, visible to the naked eye. Such changes did not occur in the samples stored at 60 MPa/−5℃ for 35 days. The results showed that applying HS-ST at 60 MPa/−5℃ allowed the shelf-life of raw pork sausages to be effectively extended by at least 35 days without visible quality deterioration.

  • Hypericum alpestre extract exhibits in vitro and in vivo anticancer properties by regulating the cellular antioxidant system and metabolic pathway of L‐arginine
    • Mikayel Ginovyan
    • Hayarpi Javrushyan
    • Hasmik Karapetyan
    • Izabela Koss-Mikołajczyk
    • Barbara Kusznierewicz
    • Anna Grigoryan
    • Alina Maloyan
    • Agnieszka Bartoszek
    • Nikolay Avtandilyan
    2024 CELL BIOCHEMISTRY AND FUNCTION

    Conventional treatment methods are not effective enough to fight the rapid increase in cancer cases. The interest is increasing in the investigation of herbal sources for the development of new anticancer therapeutics. This study aims to investigate the antitumor capacity of Hypericum alpestre (H. alpestre) extract in vitro and in vivo, either alone or in combination with the inhibitors of the L‐arginine/polyamine/nitric oxide (NO) pathway, and to characterize its active phytochemicals using advanced chromatographic techniques. Our previous reports suggest beneficial effects of the arginase inhibitor NG‐hydroxy‐nor‐L‐arginine and NO inhibitor NG‐nitro‐Larginine methyl ester in the treatment of breast cancer via downregulation of polyamine and NO synthesis. Here, the antitumor properties of H. alpestre and its combinations were explored in vivo, in a rat model of mammary gland carcinogenesis induced by subcutaneous injection of 7,12‐dimethylbenz[a]anthracene. The study revealed strong antiradical activity of H. alpestre aerial part extract in chemical (DPPH/ABTS) tests. In the in vitro antioxidant activity test, the H. alpestre extract demonstrated pro‐oxidant characteristics in human colorectal (HT29) cells, which were contingent upon the hemostatic condition of the cells. The H. alpestre extract expressed a cytotoxic effect on HT29 and breast cancer (MCF‐7) cells measured by the MTT test. According to comet assay results, H. alpestre extract did not exhibit genotoxic activity nor possessed antigenotoxic properties in HT29 cells. Overall, 233 substances have been identified and annotated in H. alpestre extract using the LC‐Q‐Orbitrap HRMS system. In vivo experiments using rat breast cancer models revealed that the H. alpestre extract activated the antioxidant enzymes in the liver, brain, and tumors. H. alpestre combined with chemotherapeutic agents attenuated cancer‐like histological alterations and showed significant reductions in tumor blood vessel area. Thus, either alone or in combination with Nω‐OH‐nor‐L‐arginine and Nω‐ nitro‐L‐arginine methyl ester, H. alpestre extract exhibits pro‐ and antioxidant, antiangiogenic, and cytotoxic effects.

  • ICT-enabled circular economy: conceptualising the links
    • Ewa Lechman
    • Radosław Ślosarski
    2024

    This chapter sets conceptual backgrounds regarding the potentially emerging causal links between digital technologies and circular economy ideas implementation. We argue that digital technologies may constitute an effective element enabling the transformation from linear to circular and environmentally friendly economic activities. This work draws the general picture at the macro and micro level. The macro perspective shows how individual actions aggregate into global ones that can be demonstrated through, for instance, waste management, resource productivity or, inter alia, statistics. Regarding the micro level, we intended to show how current business models are transforming into circular business models and how companies adopt and use digital technologies to tackle the idea of circular economy and implement it. Lastly, we draw several policy implications.

  • Ideas of the New European Bauhaus (NEB) in architectural education
    • Antoni Taraszkiewicz
    • Karolina Taraszkiewicz
    2024 Pełny tekst World Transactions on Engineering and Technology Education

    The New European Bauhaus (NEB) is an interdisciplinary project initiated by the European Commission in 2020 [1], based on three values: sustainability, beauty and community (social inclusion). Its aim is to support the European Green Deal programme [2] by accelerating the transformation of various economic sectors, including construction, to improve the quality of people’s lives and protect the natural environment. Even though the NEB ideas have been known in Europe and around the world for over three years, it turns out that they receive very little attention in contemporary architectural education in some countries. A survey conducted among students in the 4th semester of the first-cycle studies in the Faculty of Architecture at Gdańsk University of Technology, Gdańsk, Poland, indicated that students do not know the NEB ideas and do not try to implement them in their design work. Hence, the need to create an appropriate base - a school in which students are able to directly and tangibly encounter all sustainable spatial, functional, technical and technological solutions according to the values and requirements of modern society.

  • Identification of Determinants of Using Crowdfunding as a Source of Financing the Development of Social Enterprises–the Perspective of Polish Social Entrepreneurs
    • Martyna Wronka-Pośpiech
    • Aldona Frączkiewicz-Wronka
    • Maria Węgrzyn
    • Krzysztof Leja
    2024

    Social enterprises face funding challenges caused, among other things, by investors focusing too much on risk and return. As traditional capital markets do not meet the needs of social entrepreneurs, crowdfunding can be an alternative way to raise funds for the development of their business. In this context, crowd-funding has not been sufficiently researched, and its growing importance in business finance makes it worth understanding its impact on social enterprises. Therefore, this paper helps to fill this gap in the literature by analysing social entrepreneurs’ use of alternative forms of finance such as crowdfunding. The observation of social enterprise activities in Poland, which has been carried out systematically for several years, justifies the thesis that this phenomenon as a practical activity is relatively new and research is fragmentary and rather than in-depth. Hence the idea to address this very issue in this paper. Therefore, our study collects qualitative data from 21 social entrepreneurs to find out the reasons that facilitate or hinder its use by social enterprises.

  • Identification of Public Service Logic (PSL) and Public Service Motivation (PSM) elements in Open Government Data (OGD) initiatives
    • Fredrick Ishengoma
    • Shao Deo
    • Raphael Gouvêa
    • Guilherme Costa Wiedenhöft
    • Ricardo Matheus
    • Charalampos Harris Alexopoulos
    • Nina Rizun
    • Stuti Saxena
    2024 Pełny tekst Electronic Journal of Information Systems in Developing Countries

    While previous research on Open Government Data (OGD) has primarily focused on reuse and adoption, this study aims to explore the implications of the Public Service Logic (PSL) and Public Service Motivation (PSM) dimensions in the context of OGD initiatives. This study is contextualized in Tanzania wherein the OGD initiatives are at an evolving stage. For the present study, the perspectives of the 15 public officials involved in the management of the OGD initiatives are being solicited. Findings underscore the need for furthering the marketing and refurbishing the OGD initiatives' quality alongside the increased involvement of the stakeholders to engage in value co-creation. Furthermore, as a study contextualized in a developing country to understand the involvement of the public personnel in the refurbishment of the OGD initiatives, the study contributes to the extant OGD literature while identifying the OGD publisher-side challenges and strengths in a still-evolving OGD initiative. Finally, with its societal implications in terms of the impact on societal stakeholders' engagement with OGD given the PSL-PSM of the public officials, the study's relevance is also clinched

  • Identyfikacja instrumentu muzycznego z nagrania fonicznego za pomocą sztucznych sieci neuronowych
    • Maciej Blaszke
    2024 Pełny tekst

    Celem rozprawy jest zbadanie algorytmów do identyfikacji instrumentów występujących w sygnale polifonicznym z wykorzystaniem sztucznych sieci neuronowych. W części teoretycznej przywołano podstawy przetwarzania sygnałów fonicznych w kontekście ekstrakcji parametrów sygnałów wykorzystywanych w treningu sieci neuronowych. Dodatkowo dokonano analizy rozwoju metod uczenia maszynowego z uwzględnieniem podziału na sieci neuronowe pierwszej, drugiej i trzeciej generacji. Opisano także powszechnie stosowane metody archiwizowania wyników treningu sztucznych sieci neuronowych oraz wystąpień artefaktów. Na podstawie przeglądu literatury zaproponowano tezy rozprawy. W części eksperymentalnej w pierwszej kolejności opisano dostępne i zgromadzone zbiory nagrań instrumentów muzycznych oraz sposób ich przekształcenia do formy zbioru treningowego, walidacyjnego i ewaluacyjnego. Przeprowadzono eksperymenty sprawdzające zasadność zaproponowanej koncepcji na mniejszym zbiorze danych. Na tym etapie zaimplementowano modele sieci neuronowych odpowiadające stanowi wiedzy w kontekście identyfikacji instrumentów muzycznych w celu porównania wyników z zaproponowanym modelami. Bazując na wstępnych wynikach, zaproponowano i przeprowadzono rozszerzone eksperymenty na zbiorze danych treningowych zawierających 13 instrumentów muzycznych, w tym rzadko występujących w typowym instrumentarium oraz w bazach muzycznych. W badaniach tych zostały wykorzystane modele sieci neuronowych drugiej oraz trzeciej (sieci impulsowe) generacji, w tym własne propozycje modeli. W końcowej części zawarto analizę uzyskanych wyników oraz omówiono wnioski z niej płynące, służące udowodnieniu tez badawczych. Przedstawiono również najważniejsze osiągnięcia rozprawy oraz kierunki rozwoju badań, mających na celu identyfikację instrumentów muzycznych w sygnale polifonicznym.

  • Imadła maszynowe
    • Adam Barylski
    2024 Projektowanie i Konstrukcje Inżynierskie

    omówiono pokrótce historie imadeł. Przedstawiono budowę imadeł śrubowych, samocentrujących, precyzyjnych, dwudzielnych, uchylno-obrotowych, krzyżowych, hydraulicznych i o konstrukcji blokowej. Podano zakres stosowania poszczególnych rozwiązań.

  • Imidazole-Based Lithium Salt LiHDI as a Solid Electrolyte Interphase-Stabilising Additive for Lithium-Conducting Electrolytes
    • Marek Broszkiewicz
    • Bartosz Brzozowski
    • Tomasz Trzeciak
    • Aldona Zalewska
    • Jacek Ryl
    • Leszek Niedzicki
    2024 Pełny tekst MOLECULES

    Lithium salt LiHDI (lithium 4,5-dicyano-2-(n-heptafluoropropyl)imidazolide) is proposed as a solid electrolyte interphase-stabilising additive for lithium-ion batteries, which can be added in a smaller amount than fluoroethylene carbonate (FEC) and vinylene carbonate (VC) additives. Electrolytes containing either lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide (LiTDI) or battery-standard LiPF6 were tested with various amounts of LiHDI additive. Chemical stability in the presence of water and the thermal stability of LiHDI are on par with LiTDI. LiHDI additive does not negatively affect the properties of electrolytes. Conductivity measurements of solutions, galvanostatic cycling of graphite-LiFePO4 cells at room temperature, cells’ cycling at 60 °C, internal cell resistance monitoring during cycling, and XPS analysis of electrodes’ surfaces after cycling have been performed. LiHDI, unlike the FEC-VC mixture, does not negatively affect the properties of the electrolyte. Cycling showed improved capacity retention with LiHDI additive with both graphite and LiFePO4 as capacity-limiting electrodes over samples without additives. At elevated temperatures, samples with LiHDI exhibited better capacity retention during cycling than those with FEC-VC. Internal cell resistance can be correlated with capacity retention. XPS results show changes in the composition of SEI depending on the composition of the electrolyte and the duration of cycling.

  • Imitating Quantum Probabilities: Beyond Bell’s Theorem and Tsirelson Bounds
    • Marek Czachor
    • Kamil Nalikowski
    2024 Pełny tekst Foundations of Science

    Local hidden-variable model of singlet-state correlations discussed in M. Czachor, Acta Phys. Polon. A 139, 70, is shown to be a particular case of an infinite hierarchy of local hidden-variable models based on an infinite hierarchy of calculi. Violation of Bell-type inequalities can be interpreted as a `confusion of languages' problem, a result of mixing different but neighboring levels of the hierarchy. Mixing of non-neighboring levels results in violations beyond the Tsirelson bounds.

  • Immersion in Virtual Reality: CAVE Automatic Virtual Environments vs. Head-Mounted Displays
    • Michał Mielcarek
    • Miłosz Rzeźniczak
    • Jacek Lebiedź
    2024

    The paper describes immersive capabilities of CAVE Automatic Virtual Environment and Head-Mounted Display. An important aspect of this research was to develop a method for quantifying user immersion in both systems. Two virtual reality applications, "Flat of Negative Emotions" and "Arachnophobia Treatment Support" were used to observe and analyze user reactions and engagement levels. Participants were exposed to these applications in both environments, allowing for a comparative analysis of the technologies. The methodology incorporated surveys, observation forms, and direct interaction analysis, combining qualitative and quantitative data for a comprehensive evaluation of both systems. The study involved 124 participants from varied backgrounds. The paper presents the objectives, methodology, and findings, with a focus on comparing the immersion levels in CAVE and HMD settings. The results contribute to the academic discourse in virtual reality and human-computer interaction, offering methodological advancements in measuring immersion and guiding future research in immersive technology.

  • Immune escape of B-cell lymphoblastic leukemic cells through a lineage switch to acute myeloid leukemia
    • Karolina Bełdzińska-Gądek
    • Ewa Zarzycka
    • Krzysztof Pastuszak
    • Katarzyna Borman
    • Krzysztof Lewandowski
    • Jan M. Zaucha
    • Witold Prejzner
    2024 LEUKEMIA & LYMPHOMA

    Acute leukemia (AL) with a lineage switch (LS) is associated with poor prognosis. The predisposing factors of LS are unknown, apart from KMT2A rearrangements that have been reported to be associated with LS. Herein, we present two cases and review all 104 published cases to identify risk factors for LS. Most of the patients (75.5%) experienced a switch from the lymphoid phenotype to the myeloid phenotype. Eighteen patients (17.0%) experienced a transformation from acute myelogenous leukemia (AML) to acute lymphoblastic leukemia (ALL). Forty-nine (46.2%) patients carried a KMT2A rearrangement. Most of the cases involved LS from B-cell ALL (B-ALL) to AML (59.4%), and 49 patients (46.2%) carried KMT2A-rearrangements. Forty patients (37.7%) received lineage-specific immunotherapy. Our findings suggest that the prevalence of KMT2A rearrangements together with the lineage-specific immunotherapy may trigger LS, which supports the thesis of the existence of leukemia stem cells that are capable of lymphoid or myeloid differentiation.

  • Impact Assessment of Electric Vehicles Integration and Optimal Charging Schemes Under Uncertainty: A Case Study of Qatar
    • Sheetal Deshmukh
    • Hanan Tariq
    • Mohammad Amir
    • Atif Iqbal
    • Mousa Marzband
    • Abdullah M. A. B. Al-Wahedi
    2024 Pełny tekst IEEE Access

    The integration of electric vehicles (EVs) is rapidly growing compared to conventional vehicles in Qatar. To assess how these electric vehicles will impact Qatar’s distribution network, it is necessary to accurately model EV loads. However, EV loads exhibit uncertainties due to driving behaviour in charging time, state of charge (SOC), number of trips, and distance travelled. This necessitates the development of a probabilistic model. The Monte-Carlo method is employed to predict EV charging profiles probabilistically. The generated EV load profiles are assigned to different sectors and compared with the base case voltage profile curve. The IEEE-33 bus system is utilized to evaluate EV impacts considering the load pattern of Qatar. EV load profile generation is performed using MATLAB software, and impact assessment is conducted in DIgSILENT software. The results indicate that following EV integration, the system’s voltage profile experiences drops in the early morning and afternoon. A proposed charging scheme (R2), coupled with the integration of solar PV into the system, can mitigate this voltage drop issue. The PV panels have a rating of 1503 kW and are connected to the 14th bus. In Qatar, the hot summer months span from June to September, so the average PV generation data for September is used. The implementation of the proposed reward charging scheme improves system performance in terms of the voltage profile, ensuring grid resilience.

  • Impact of abiotic stressors on nutrient removal and rhizomicrobiome composition in floating treatment wetland with Equisetum hyemale
    • Nicole Nawrot
    • Przemysław Kowal
    • Ewa Wojciechowska
    • Ksenia Pazdro
    • Jolanta Walkusz-miotk
    • Sławomir Ciesielski
    • Filip M. G. Tack
    2024 Pełny tekst SCIENCE OF THE TOTAL ENVIRONMENT

    Floating treatment wetlands (FTW) are receiving growing interest as a phyto-technology. However, there are significant research gaps regarding the actual role of plant species and plant-microbiome interactions. In this study, the nutrient uptake of Equisetum hyemale was examined in FTW microcosms under the influence of abiotic stressors: As (3 mg/L) and Pb (3 mg/L) as well as Cl− (300 and 800 mg/L) in reference to a control during a short screening experiment. High removal efficiency of nutrients in water solutions, up to 88 % for TN and 93 % for PO4-P, was observed. However, PO4-P removal was inhibited in the As reactor, with a maximum efficiency of only 11 %. Lead and As were removed with high efficiency, reaching 98 % and 79 % respectively. At the same time only Pb was effectively bound to root biomass, reaching up to 51 %. Limited As accumulation of 0.5 % in plant roots suggests that microbial processes play a major role in its reduction. The development and structure of microbiome in the microcosms was analysed by means of 16S rRNA gene amplicon sequencing, proving that Pb was the most influential factor in terms of selection pressure on specified bacterial groups. In the As treatment, the emergence of a Serratia subpopulation was observed, while the Cl− treatment preserved a rhizobiome composition most closely resembling the control. This study indicates that E. hyemale is a suitable species for use in FTWs treating Pb polluted water that at the same time is capable to withstand periodic increases in salinity. E. hyemale exhibits low As binding in biomass; however, extended exposure might amplify this effect because of the slow-acting, but beneficial, mechanism of As uptake by roots and shoots. Microbiome analysis complements insights into mechanisms of FTW performance and impact of stress factors on bacterial structure and functions.

  • Impact of Brake Wear Particles on Eukaryotic Cell Viability and Associated Oxidative Stress Responses
    • Lina Trečiokaitė
    • Yurii Tsybrii
    • Oleksii Nosko
    • Lina Ragelienė
    2024 Pełny tekst Lubricants

    In this study, the cytotoxic effects of brake wear particles (≥250 nm ceramic/ceramic wear particles (CCWPs) and ≤100 nm ceramic/steel wear particles (CSWPs)) and 100 nm iron (III) oxide ultrafine particles (IOUFPs) on human lung carcinoma (A549) and Chinese hamster ovary (CHO) cells were investigated. Cell viability was determined using the MTT and Calcein AM methods. Oxidative stress was assessed by measuring reactive oxygen species (ROS), intracellular reduced glutathione (GSH), and malondialdehyde (MDA) concentrations under exposure to the above particles in the concentration range of 10–80 µg/mL. The initial assessments of CCWPs and CSWPs on the cell viability were performed after a 4-h exposure but later extended to 24 h to investigate the time-dependent of the cell viability and oxidative stress. MTT and Calcein AM assays indicated that the A549 cells are less susceptible to CCWPs and CSWPs than the CHO cells when exposed for both 4 h and 24 h. This study highlights that oxidative stress induced by CCWPs, CSWPs, and IOUFPs is cell-specific. While CCWPs did not affect glutathione (GSH) levels in the CHO cells, it significantly reduced GSH levels in A549 cells, with the exception of 80 µg/mL. Both CCWPs and CSWPs increased the lipid peroxidation in both cell types; however, the A549 cells demonstrated lower sensitivity to these treatments.

  • Impact of emerging pollutants mixtures on marine and brackish phytoplankton: diatom Phaeodactylum tricornutum and cyanobacterium Microcystis aeruginosa
    • Lilianna Sharma
    • Błażej Kudłak
    • Joanna Stoń-Egiert
    • Grzegorz Siedlewicz
    • Ksenia Pazdro
    2024 Pełny tekst SCIENCE OF THE TOTAL ENVIRONMENT

    Pharmaceuticals and ionic liquids (ILs) are emerging as significant micropollutants with environmental presence and potential ecological impacts. The possible simultaneous occurrence of these two groups of pollutants in aquatic environments raises complex challenges due to their diverse chemical properties and potential for interactive effects. Given the documented widespread presence of pharmaceuticals and the emerging concerns about ILs, the study aims to evaluate the adverse effects of binary mixtures of imidazolium ionic liquid IM1-8C (CN)3 and two representatives of pharmaceuticals: antibiotic oxytetracycline (OXTC) and metabolite carbamazepine 10,11 epoxide (CBZ-E) on the brackish cyanobacterium Microcystis aeruginosa and the marine diatom Phaeodactylum tricornutum during chronic exposure experiments. A comprehensive approach was employed, incorporating various endpoints including oxidative stress, chlorophyll a fluorescence, detailed photoprotective and photosynthetic pigment profiles of target microorganisms to assess modes of action and identify the mixture effects of the selected substances.

  • Impact of high-pressure processing on the bioactive compounds of milk - A comprehensive review
    • Shahida Anusha Siddiqui
    • Sipper Khan
    • Nur Alim Bahmid
    • Andrey Ashotovich Nagdalian
    • Seid Mahdi Jafari
    • Roberto Castro Munoz
    2024 Pełny tekst JOURNAL OF FOOD SCIENCE AND TECHNOLOGY-MYSORE

    High-pressure processing (HPP) is a promising alternative to thermal pasteurization. Recent studies highlighted the effectivity of HPP (400–600 MPa and exposure times of 1–5 min) in reducing pathogenic microflora for up to 5 logs. Analysis of modern scientific sources has shown that pressure affects the main components of milk including fat globules, lactose, casein micelles. The behavior of whey proteins under HPP is very important for milk and dairy products. HPP can cause significant changes in the quaternary (> 150 MPa) and tertiary (> 200 MPa) protein structures. At pressures > 400 MPa, they dissolve in the following order: αs2-casein, αs1-casein, k-casein, and β-casein. A similar trend is observed in the processing of whey proteins. HPP can affect the rate of milk fat adhering as cream with increased results at 100–250 MPa with time dependency while decreasing up to 70% at 400–600 MPa. Some studies indicated the lactose influencing casein on HP, with 10% lactose addition in case in suspension before exposing it to 400 MPa for 40 min prevents the formation of large casein micelles. Number of researches has shown that moderate pressures (up to 400 MPa) and mild heating can activate or stabilize milk enzymes. Pressures of 350–400 MPa for 100 min can boost the activity of milk enzymes by up to 140%. This comprehensive and critical review will benefit scientific researchers and industrial experts in the field of HPP treatment of milk and its effect on milk components.