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Gdańsk University of Technology

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  • Assessment of codes recommendations for the evaluation of the seismic gap of buildings founded on different soil types
    • Mahmoud Miari
    • Robert Jankowski
    2023 AIP Conference Proceedings

    Several equations have been proposed in the literature to evaluate the seismic gap preventing earthquake-induced structural pounding, such as the ones based on the absolute sum of the peak displacements (ABS), the square root of the sum of the squares (SRSS), the double difference method (DDC), Australian code and the approach proposed by Naderpour et al. The aim of this paper is to investigate the accuracy of these equations taking the soil type into consideration. Three buildings have been considered, which are 5-storey, 7-storey and 9-storey buildings. Three possible pounding scenarios have been considered between these three buildings which are pounding between 5-storey and 7-storey buildings, pounding between 5-storey and 9-storey buildings and pounding between 7-storey and 9-storey buildings. Five soil types have been taken into account, which are soil types defined in the ASCE 7-10 code (hard rock, rock, very dense soil and soft rock, stiff soil and soft clay soil). The result of this study shows that the ABS and Naderpour formulas are always conservative, but they overestimate the gap. Indeed, the SRSS, DDC and Australian code formulas provide overestimate, accurate and nonconservative results.

  • Assessment of Sewage Molecular Markers: Linear Alkylbenzenes in Sediments of an Industrialized Region in Peninsular Malaysia
    • Sadeq Abdullah Abdo Alkhadher
    • Hussein Al-Hazmi
    • Suhaimi Suratman
    • Mohamad Pauzi Zakaria
    • Najat Masood
    • Bartosz Szeląg
    • Sami M. Magam
    • Ebrahim H. H. Al-Qadami
    • Joanna Majtacz
    • Przemysław Kowal
    • Tonni Agustiono Kurniawan
    • Sameer A.M. Abdulrahman
    • Saeed S. Albaseer
    2023 Full text Water

    In this study, the use of linear alkylbenzenes (LABs) was employed to pinpoint the sources of human activity that cause detrimental impacts on the coastal environment and river ecosystems. LABs were detected using GC–MS in sediment samples assembled from Kim Kim River (KKR) and the Port Dickson coast (PDC). To assess the significance of variations in the distribution and concentrations of LABs across the sampling sites, this study utilized several statistical techniques such as post hoc tests, LSD techniques, analysis of variance (ANOVA), and the Pearson correlation coefficient using a significance level of p < 0.05. The degradation levels of LABs and wastewater treatment were assessed in the study using internal congeners (I/E), homologs of C13 and C12, and long-to-short-chain (L/S) ratios. The results revealed that the LAB concentrations varied between 88.3 and 112 ng/g dw in KKR and 119 to 256 ng/g dw in the PDC. Most of the surveyed areas exhibited a substantial count of C13–LABs homologs that displayed a significant difference (p < 0.05). The I/E ratios ranged from 1.7 to 2.0 in KKR and from 2.0 to 4.1 in the PDC, suggesting that the effluents originated from sources associated with the physical phase and biological phase in wastewater treatment systems (WWTSs). The results revealed that the degradation of LABs varied between 34% and 38% in KKR and between 40% and 64% in the PDC. This study underscores the importance of ongoing improvements to WWTSs and emphasizes the potential of LABs as indicators for monitoring wastewater contamination.

  • Assessment of Subsoil Subsidence Under the Railway Surface with the Use of Fuzzy Sets
    • Eligiusz Mieloszyk
    • Anita Milewska
    • Mariusz Wyroślak
    2023 AIP Conference Proceedings

    The cause of the subsidence of the railway track is the subsidence of the track bed itself and it is often related to the subsidence of the subsoil. Such settlement leads to: uneven longitudinal railways and track twist. These phenomena have a negative impact on the comfort and safety of driving, and in extreme cases lead to a train derailment. It has been shown that the magnitude of these settlements is determined by many parameters characterizing the subgrade and subsoil as well as dynamic interactions (vibrations) generated by passing rail vehicles. The propagation of these vibrations in the subgrade and the subsoil is related to the propagation of the generated elastic waves as mechanical waves in the elastic medium which is the subgrade and further the subsoil. Fuzzy sets, operations on them and their properties were used to assess the subsidence of the subsoil under the railway surface. Using the created membership functions , = 1, 2, … , their linear combination is determined. The coefficients of this combination are selected by the AHP method. Practical applications of the created linear combination (created models) were indicated.

  • Assessment of Technical Conditions in Adapting a Historic Warehouse's Space Functionality
    • Maciej Niedostatkiewicz
    • Tomasz Majewski
    2023 Full text Modern Engineering

    The paper is a case study in the assessment of the technical condition of a building that is an immovable monument located in a former shipyard area. Due to the change in the use of the industrial area and the intention to build a production hall, it was necessary to consider the demolition of the historic building, while preserving as many of its historical aspects as possible. The paper presents a detailed description of the methodology for assessing the technical condition of a warehouse building and describes the proposed variants of its further use.

  • Assessment of the Accuracy of a Virtual Multi-Channel Temperature Measuring Instrument
    • Romuald Maśnicki
    • Beata Pałczyńska
    2023 Full text Scientific Journal of Gdynia Maritime University

    The multi-channel temperature measurement system developed works with NTC thermistors. The article presents the results of theoretical and empirical evaluation of accuracy obtained in measurement channels. The basis for the theoretical assessment is the mathematical model for each of the measurement channels and the characteristics of the system elements included in the circuits of the measurement channel. Two different methods were used to theoretically estimate the accuracy: the Gauss Formula and the Monte Carlo method. The empirical assessment of accuracy is supported by measurement data collected during the calibration procedures for the device developed and the results of verification measurements performed on a working device. The exemplary results presented of the accuracy assessment, obtained in the selected channel, are representative of the properties of all other measurement channels. The results of both methods of assessing accuracy in measurement channels are very similar, which confirms the assumptions regarding the implementation of the instrument developed and its good metrological properties.

  • Assessment of Wooden Beams from Historical Buildings Using Ultrasonic Transmission Tomography
    • Monika Zielińska
    • Magdalena Rucka
    2023 Full text International Journal of Architectural Heritage

    The main goal of this study was non-destructive evaluation of wooden elements using ultrasonic waves. The inspection was carried out on wooden beams from a historical object. Elastic wave signals were processed by ultrasonic transmission tomography to obtain imaging of the internal structure of tested elements without disturbing their state and integrity. The focus was on the influence of wood anisotropy on the propagation of ultrasonic waves. A novel method of determining the position of the cross-section pith was proposed. The study presented that the proposed imaging approach was capable to assess the technical condition of historic wooden beams by determining the degree of wood damage and the location of discontinuities, scratches or fibrosis in the tested cross-section.

  • Assessment, optimisation and working fluid comparison of organic rankine cycle combined with negative CO2 gas power plant system
    • Kamil Stasiak
    • Paweł Ziółkowski
    • Dariusz Mikielewicz
    2023 Full text

    This study aims to investigate the application of the Organic Rankine Cycle (ORC) as an alternative to low-pressure expansion in the negative CO2 power plant (nCO2PP). The reason for this study is that a detailed analysis of nCO2PP indicates a certain amount of waste heat present in the exhaust gas from the high-to-intermediate pressure gas turbine. Some of this energy can be used by the application of the expansion in a low-pressure turbine, optionally the application of regenerative water heating, which is further directed to the combustion chamber, and alternatively the combination of the ORC into the main cycle. For the ORC cycle, various configurations are examined, either with or without regenerative water heating and using different working mediums. For the highest cycle efficiency, regenerative heating of high-pressure water is applied, and proper ORC working fluid with optimum saturation point and mass flow is selected. Such modified nCO2PP power plant hybrid systems with ORC are compared to the original concept of nCO2PP with lower pressure expansion. A hybrid system integrating the advantages of nCO2PP and an ORC cycle is a promising solution, and modifications are possible, but the main advantage is that an ORC cycle can be introduced as a component to provide electrical power in the lower temperature range. Three ORC mediums were calculated, namely ethanol, refrigerants R236-ea and R245-fa which yielded net efficiency of the whole power plant of 38.35%, 40.16% and 40.39% respectively, while the original nCO2PP yielded 38.89%.

  • Asymptomatic Bacteriuria in Kidney Transplant Recipients—A Narrative Review
    • Justyna Gołębiewska
    • Beata Krawczyk
    • Wysocka Magdalena
    • Aleksandra Dudziak
    • Alicja Dębska-ślizień
    2023 Full text Medicina

    Urinary tract infections (UTIs) are the most prevalent complications in kidney transplant (KTx) recipients. The most frequent finding in this group of patients is asymptomatic bacteriuria (ASB). Here, we provide an overview of the available evidence regarding ASB in KTx recipients, including its etiopathology, clinical impact and management. There is a growing body of evidence from clinical trials that screening for and treating ASB is not beneficial in most KTx recipients. However, there are insufficient data to recommend or discourage the use of a “screen-and-treat strategy” for ASB during the first 1–2 months post-transplant or in the case of an indwelling urinary catheter. Despite its frequency, ASB after KTx is still an understudied phenomenon.

  • Asynchronous Charge Carrier Injection in Perovskite Light-Emitting Transistors
    • Maciej Klein
    • Krzysztof Blecharz
    • Bryan Hao, Wei
    • Annalisa Bruno
    • Cesare Soci
    2023 Full text Advanced Electronic Materials

    Unbalanced mobility and injection of charge carriers in metal-halide perovskite light-emitting devices pose severe limitations to the efficiency and response time of the electroluminescence. Modulation of gate bias in methylammonium lead iodide light-emitting transistors has proven effective in increasing the brightness of light emission up to MHz frequencies. In this work, a new approach is developed to improve charge carrier injection and enhance electroluminescence of perovskite light-emitting transistors by independent control of drain–source and gate–source bias voltages to compensate for space-charge effects. Optimization of bias pulse synchronization induces a fourfold enhancement of the emission intensity. Interestingly, the optimal phase delay between biasing pulses depends on modulation frequency due to the capacitive nature of the devices, which is well captured by numerical simulations of an equivalent electrical circuit. These results provide new insights into the electroluminescence dynamics of AC-driven perovskite light-emitting transistors and demonstrate an effective strategy to optimize device performance through independent control of the amplitude, frequency, and phase of the biasing pulses.

  • Asynchronous Method of Simultaneous Object Position and Orientation Estimation with Two Transmitters
    • Jacek Stefański
    • Jarosław Sadowski
    2023 Full text Navigation-Journal of the Institute of Navigation

    This paper proposes an object location method for all types of applications, including the Internet of Things. The proposed method enables estimations of the position and orientation of an object on a plane or in space, especially during motion, by means of location signals transmitted simultaneously from two transmitters placed on the object at a known distance from each other. A mathematical analysis of the proposed method and Newton’s algorithm for solving the system of nonlinear positional equations is presented. Next, an analysis of a position-dilution-of-precision parameter for the proposed method and a Cramer–Rao lower bound, limiting the accuracy of the method, is presented. Finally, the results of complex simulation studies on the efficiency of the proposed method are described.

  • Atmospheric degradation mechanism of anthracene initiated by OH•: A DFT prediction
    • Farzaneh Shahsavar
    • Ehsan Zahedi
    • Abolfazl Shiroudi
    • Behzad Chahkandi
    2023 JOURNAL OF MOLECULAR GRAPHICS & MODELLING

    Density functional theory (DFT) calculations at the M06-2X/def2-TZVP level have been employed to investigate the atmospheric oxidation mechanism of anthracene (ANT) initiated by HO•. Direct hydrogen atom abstraction from the ANT using HO• takes place hardly at ambient conditions while the addition of HO• to the C1, C2, and C4 sites are thermodynamically and kinetically more advantageous. The addition reactions are controlled by the aromaticity and the kinetic trends were justified by resonance stabilization energies. The rate constants were calculated by using the Rice-Ramsperger-Kassel-Marcus (RRKM) and canonical transition state theory (CTST) methods in conjugation with zero curvature tunneling (ZCT). The overall RRKM-bimolecular rate constant at ambient conditions is 6.72 × 10−12 cm3 molecule−1 s−1, is negatively dependent on the temperature and can be expressed as k=3.92*10-14 exp(1534.9/T). Contribution of the AD-C4 path in the overall reaction is about 70–80%, implying that the dependence of overall rate constant on pressure can be ignored. The kinetic data exhibit that the ANT is degraded during its long-range transport in the atmosphere and cannot be classified as persistent organic pollutants.

  • Attention-Based Deep Learning System for Classification of Breast Lesions—Multimodal, Weakly Supervised Approach
    • Maciej Bobowicz
    • Marlena Rygusik
    • Jakub Buler
    • Rafał Buler
    • Maria Ferlin
    • Arkadiusz Kwasigroch
    • Edyta Szurowska
    • Michał Grochowski
    2023 Full text Cancers

    Breast cancer is the most frequent female cancer, with a considerable disease burden and high mortality. Early diagnosis with screening mammography might be facilitated by automated systems supported by deep learning artificial intelligence. We propose a model based on a weakly supervised Clustering-constrained Attention Multiple Instance Learning (CLAM) classifier able to train under data scarcity effectively. We used a private dataset with 1174 non-cancer and 794 cancer images labelled at the image level with pathological ground truth confirmation. We used feature extractors (ResNet-18, ResNet-34, ResNet-50 and EfficientNet-B0) pre-trained on ImageNet. The best results were achieved with multimodal-view classification using both CC and MLO images simultaneously, resized by half, with a patch size of 224 px and an overlap of 0.25. It resulted in AUC-ROC = 0.896 ± 0.017, F1-score 81.8 ± 3.2, accuracy 81.6 ± 3.2, precision 82.4 ± 3.3, and recall 81.6 ± 3.2. Evaluation with the Chinese Mammography Database, with 5-fold cross-validation, patient-wise breakdowns, and transfer learning, resulted in AUC-ROC 0.848 ± 0.015, F1-score 78.6 ± 2.0, accuracy 78.4 ± 1.9, precision 78.8 ± 2.0, and recall 78.4 ± 1.9. The CLAM algorithm’s attentional maps indicate the features most relevant to the algorithm in the images. Our approach was more effective than in many other studies, allowing for some explainability and identifying erroneous predictions based on the wrong premises.

  • Attenuation of Hyperglycemia in Diabetic Rats Assisted by Immobilized Probiotic in Sodium Alginate
    • José J. Arriaga-Morales
    • Cynthia Ordaz-Pichardo
    • Roberto Castro Munoz
    • Enrique Durán-Páramo
    2023 Full text Probiotics and Antimicrobial Proteins

    Diabetes mellitus type 2 (DM2) is the most common chronic disease worldwide, characterized mainly by increased glucose concentration in the blood and affecting several organs’ functionality. The daily consumption of probiotic bacteria can help control diabetes and reduce the damage caused. Cell immobilization techniques are a powerful tool that provides physical cell protection to such probiotic bacteria against gastrointestinal conditions. We suggest that cell immobilization could be a significant vector for delivering a high quantity of viable probiotics to the gut, helping attenuate hyperglycemia in diabetic rats. Seventy male Wistar rats were used in this work. Nicotinamide was administrated via intraperitoneal injection 15 minutes before inducing type 2 diabetes (DM2), followed by a second intraperitoneal injection of streptozotocin to induce DM2. Rats were divided into seven groups. For 45 days, a specific treatment was applied to each group. The group of rats, supplied with immobilized Lactobacillus casei, showed a serum glucose concentration of 137 mg/dL, which was close to the one observed in the groups of healthy rats (117 mg/dL) and rats treated with metformin (155 mg/dL). The diabetic rats without treatment presented a higher serum glucose concentration (461 mg/dL). In the rats treated with immobilized L. casei, there was no biochemical parameter alteration, and the cell morphology of the analyzed tissues was similar to those of the healthy group. The consumption of immobilized L. casei could allow a high quantity of viable probiotics to be delivered to the gut, reducing serum glucose concentration by up to 70% compared to diabetic rats and reducing organ damage caused by diabetes.

  • Attractors of dissipative homeomorphisms of the infinite surface homeomorphic to a punctured sphere
    • Grzegorz Graff
    • Rafael Ortega
    • Alfonso Ruiz-Herrera
    2023 Full text COMMUNICATIONS IN CONTEMPORARY MATHEMATICS

    A class of dissipative orientation preserving homeomorphisms of the infinite annulus,pairs of pants, or generally any infinite surface homeomorphic to a punctured sphere isconsidered. We prove that in some isotopy classes the local behavior of such homeomor-phisms at a fixed point, namely the existence of so-called inverse saddle, impacts thetopology of the attractor — it cannot be arcwise connected

  • Audio Content and Crowdsourcing: A Subjective Quality Evaluation of Radio Programs Streamed Online
    • Przemysław Falkowski-Gilski
    2023

    Radio broadcasting has been present in our lives for over 100 years. The transmission of speech and music signals accompanies us from an early age. Broadcasts provide the latest information from home and abroad. They also shape musical tastes and allow many artists to share their creativity. Modern distribution involves transmission over a number of terrestrial systems. The most popular are analog FM (Frequency Modulation) and digital DAB+ (Digital Audio Broadcasting plus). It is worth mentioning that the same content is delivered simultaneously in several techniques, referred to as simulcasting. In addition, the vast majority of radio stations broadcast the same audio content online as well. Their signals are available through dedicated mobile applications for popular mobile devices running the Android or iOS operating system. In turn, other broadcasters offer content through their own website or third-party services associating several radio programs. Such a situation may be observed both on the local (regional) and national (state) market all around the world in America, Europe, Asia, etc. When it comes to terrestrial radio, contrary to analog FM broadcasting, digital signals are grouped into a set, referred to as the multiplex ensemble. It should be emphasized that the costs associated with regular broadcasting of radio programs are much lower in case of the digital standard. The entire process and fees related to the collection and processing of audio signals and associated additional data, as well as the formation and emission of the multiplex collective signal, can be distributed among several or even a dozen shareholders. The total net bitrate can be flexibly distributed depending on the broadcaster’s profile and target audience, played music genre, etc., according to the established needs. Another approach related to the digital broadcasting of radio signals is the on-demand availability of content in the form of the so-called podcast. The listener is able to choose a previously recorded material through the web browser or a mobile application. Considering the number of available radio programs and the broad range of content they create, this form seems perfectly justified. In case of broadcasting radio programs online, referred to as streaming, speech and music signals and associated multimedia (e.g., album cover, author information, etc.) are available live in real-time. Of course, the transmission medium is different.

  • Audyt Krajobrazowy Województwa Pomorskiego. Karta Krajobrazu Priorytetowego. Żuławy: Wróblewo Opinia Ekspercka
    • Marta Koperska-Kośmicka
    2023

    Opinia ekspercka dla Karty Krajobrazu Priorytetowego Żuławy: Wróblewo, symbol obszaru: 22-313.54-91, do Audytu Krajobrazowego Województwa Pomorskiego

  • Audyt Krajobrazowy Województwa Pomorskiego. Karta Krajobrazu Priorytetowego. Żuławy: Złotowo. Opinia Ekspercka
    • Marta Koperska-Kośmicka
    2023

    Opinia ekspercka dla Karty Krajobrazu Priorytetowego Żuławy: Złotowo, symbol obszaru: 22-313.54-83, do Audytu Krajobrazowego Województwa Pomorskiego

  • Audyt Krajobrazowy Województwa Pomorskiego Opinia ekspercka dla Karty Krajobrazu Priorytetowego Nizina Walichnowska, symbol obszaru: 22-314.81-7
    • Marta Koperska-Kośmicka
    2023

    Audyt Krajobrazowy Województwa Pomorskiego Opinia ekspercka dla Karty Krajobrazu Priorytetowego Nizina Walichnowska, symbol obszaru: 22-314.81-7

  • Audyt Krajobrazowy Województwa Pomorskiego. Opinia ekspercka dla Karty Krajobrazu Priorytetowego Żuławy: Kmiecin-Marynowy-Lubieszewo, symbol obszaru: 22-313.54-87
    • Marta Koperska-Kośmicka
    2023

    Audyt Krajobrazowy Województwa Pomorskiego. Opinia ekspercka dla Karty Krajobrazu Priorytetowego Żuławy: Kmiecin-Marynowy-Lubieszewo, symbol obszaru: 22-313.54-87

  • Augmented speed control scheme of dual induction motors with mutual flux angle control loop
    • Dmytro Kondratenko
    • Arkadiusz Lewicki
    • Krzysztof Łuksza
    2023 Full text Archives of Electrical Engineering

    This paper proposes an augmented speed control scheme of dual induction motors fed by a five-leg voltage source inverter (VSI) with a common/shared-leg. An additional control loop is proposed here and based on the mutual flux angle – the difference between flux angular positions of the IMs. The main purpose of this research is to minimize the energy losses in the common inverter leg by controlling the mutual flux angle, at equal angular speeds of both motors. Simulation and experimental studies were carried out and the effectiveness of the proposed control method was proven. The PLECS software package was used for the simulation tests. The laboratory prototype was prepared for the experimental validation. All results were provided and discussed in this paper.

  • Autistic Employees’ Technology-Based Workplace Accommodation Preferences Survey—Preliminary Findings
    • Michał Tomczak
    • Paweł Ziemiański
    2023 Full text International Journal of Environmental Research and Public Health

    Background: There has been an increase in the number of research studies focused on the design of accommodations aimed at improving the well-being and work performance of autistic employees. These accommodations took various forms; some of them were based on modification of management practices, for example, support in the area of effective communication, or involved modifications to the physical working environment aimed at limiting sensory vulnerabilities. Many of these solutions were based on digital technology. Methods: This quantitative research aimed to learn about the opinions of the autistic respondents as potential end users and their assessment of the proposed solutions within four main challenge areas: (1) effective communication; (2) time management, task prioritizing, and organization of work; (3) stress management and emotion control; and (4) sensory sensitivities. Results: Respondents gave the highest ratings to solutions aimed at limiting overstimulation and a flexible approach toward working time, support of a job coach, remote work, and support by allowing electronic-mediated communication based on non-direct contact. Conclusions: The results can be the starting point for further research on the highest rated solutions dedicated to improving working conditions and the well-being of autistic employees and can be an inspiration for employers who plan to introduce such solutions.

  • Autoencoder application for anomaly detection in power consumption of lighting systems
    • Tomasz Śmiałkowski
    • Andrzej Czyżewski
    2023 Full text IEEE Access

    Detecting energy consumption anomalies is a popular topic of industrial research, but there is a noticeable lack of research reported in the literature on energy consumption anomalies for road lighting systems. However, there is a need for such research because the lighting system, a key element of the Smart City concept, creates new monitoring opportunities and challenges. This paper examines algorithms based on the deep learning method using the Autoencoder model with LSTM and 1D Convolutional networks for various configurations and training periods. The evaluation of the algorithms was carried out based on real data from an extensive lighting control system. A practical approach was proposed using real-time, unsupervised algorithms employing limited computing resources that can be implemented in industrial devices designed to control intelligent city lighting. An anomaly detection algorithm based on classic LSTM networks, single-layer and multi-layer, was used for comparison purposes. Error matrix calculus was used to assess the quality of the models. It was shown that based on the Autoencoder method, it is possible to construct an algorithm that correctly detects anomalies in power measurements of lighting systems, and it is possible to build a model so that the algorithm works correctly regardless of the season of the year.

  • Automated anonymization of sensitive data on production unit
    • Marcin Kujawa
    • Robert Piotrowski
    2023 Full text Journal of Automation, Mobile Robotics and Intelligent Systems - JAMRIS

    The article presents an approach to data anonymization with the use of generally available tools. The focus is put on the practical aspects of using open-source tools in conjunction with programming libraries provided by suppliers of industrial control systems. This universal approach shows the possibilities of using various operating systems as a platform for process data anonymization. An additional advantage of the described approach is the ease of integration with various types of advanced data analysis tools based both on the out-of-the-box approach (e.g., business intelligence tools) as well as customized solutions. The discussed case describes the anonymization of data for the needs of sensitive analysis by a wider group of recipients during the construction of a predictive model used to support decisions.

  • Automated detection of pronunciation errors in non-native English speech employing deep learning
    • Daniel Korzekwa
    2023 Full text

    Despite significant advances in recent years, the existing Computer-Assisted Pronunciation Training (CAPT) methods detect pronunciation errors with a relatively low accuracy (precision of 60% at 40%-80% recall). This Ph.D. work proposes novel deep learning methods for detecting pronunciation errors in non-native (L2) English speech, outperforming the state-of-the-art method in AUC metric (Area under the Curve) by 41%, i.e., from 0.528 to 0.749. One of the problems with existing CAPT methods is the low availability of annotated mispronounced speech needed for reliable training of pronunciation error detection models. Therefore, the detection of pronunciation errors is reformulated to the task of generating synthetic mispronounced speech. Intuitively, if we could mimic mispronounced speech and produce any amount of training data, detecting pronunciation errors would be more effective. Furthermore, to eliminate the need to align canonical and recognized phonemes, a novel end-to-end multi-task technique to directly detect pronunciation errors was proposed. The pronunciation error detection models have been used at Amazon to automatically detect pronunciation errors in synthetic speech to accelerate the research into new speech synthesis methods. It was demonstrated that the proposed deep learning methods are applicable in the tasks of detecting and reconstructing dysarthric speech.

  • Automatic audio signal mixing system based on one-dimensional Wave-U-Net autoencoders
    • Damian Koszewski
    2023 Full text

    The purpose of this dissertation is to develop an automatic song mixing system that is capable of automatically mixing a song with good quality in any music genre. This work recalls first the audio signal processing methods used in audio mixing, and it describes selected methods for automatic audio mixing. Then, a novel architecture built based on one-dimensional Wave-U-Net autoencoders is proposed for automatic music mixing. Models are trained on a custom-made database. Mixes created using the proposed system are compared with amateur, state-of-the-art software and professional mixes prepared by audio engineers. The achieved results prove that mixes created automatically by Wave-U-Net can objectively be evaluated as highly as mixes created professionally. This is also confirmed by the statistical analysis of the results of the conducted listening tests. The results show a strong correlation between the experience of the listeners in mixing and the likelihood of a higher rating of the Wave-U-Net mix and the professional mix than the amateur mix or the mix prepared using state-of-the-art software. These results are also confirmed by the results of the similarity matrix-based analysis.

  • Automatic Correction of Non-Anechoic Antenna Measurements using Low-Pass Filters
    • Adrian Bekasiewicz
    • Vorya Waladi
    • Marek Wójcikowski
    • Tuan-Vu Cao
    2023 Full text

    Prototype measurements belong to key steps in the development of antenna structures. They are normally performed in expensive facilities, such as anechoic chambers (ACs). Alternatively, antenna performance can be extracted (at a low cost) in non-anechoic conditions upon appropriate post-processing. Unfortunately, existing correction algorithms are difficult to set up and prone to failure, which limits their practical usefulness. In this work, a method for refining far-field antenna responses that exploits a series of low-pass filters with automatically determined properties has been proposed. Its performance has been demonstrated using a geometrically small antipodal Vivaldi radiator measured in an office room. The approach has been favorably compared against the state-of-the-art techniques from the literature.

  • Automatic music signal mixing system based on one-dimensional Wave-U-Net autoencoders
    • Damian Koszewski
    • Thomas Görne
    • Grazina Korvel
    • Bożena Kostek
    2023 Full text EURASIP Journal on Audio Speech and Music Processing

    The purpose of this paper is to show a music mixing system that is capable of automatically mixing separate raw recordings with good quality regardless of the music genre. This work recalls selected methods for automatic audio mixing first. Then, a novel deep model based on one-dimensional Wave-U-Net autoencoders is proposed for automatic music mixing. The model is trained on a custom-prepared database. Mixes created using the proposed system are compared with amateur, state-of-the-art software, and professional mixes prepared by audio engineers. The results obtained prove that mixes created automatically by Wave-U-Net can objectively be evaluated as highly as mixes prepared professionally. This is also confirmed by the statistical analysis of the results of the conducted listening tests. Moreover, the results show a strong correlation between the experience of the listeners in mixing and the likelihood of a higher rating of the Wave-U-Net-based and professional mixes than the amateur ones or the mix prepared using state-of-the-art software. These results are also confirmed by the outcome of the similarity matrix-based analysis.

  • AUTOMATYCZNA KLASYFIKACJA MOWY PATOLOGICZNEJ
    • Martyna Włoszczyńska
    • Bożena Kostek
    2023

    Aplikacja przedstawiona w niniejszym rozdziale służy do automatycznego wykrywania mowy patologicznej na podstawie bazy nagrań. W pierwszej kolejności przedstawiono założenia leżące u podstaw przeprowadzonych badan wraz z wyborem bazy mowy patologicznej. Zaprezentowano również zastosowane algorytmy oraz cechy sygnału mowy, które pozwalają odróżnić mowę niezaburzoną od mowy patologicznej. Wytrenowane sieci neuronowe zostały następnie wykorzystane w aplikacji, która umożliwia przeprowadzenie klasyfikacji binarnej na sygnale mowy. Uzyskane wyniki klasyfikacji mowy niezaburzonej i patologicznej zostały porównane z wynikami opisanymi w literaturze przedmiotu. W podsumowaniu zamieszczono również wnioski oraz propozycje rozwoju prowadzonych badań.

  • Awaryjne przekształcenia architektury szpitali w warunkach pandemii SARS-CoV-2
    • Agnieszka Gębczyńska-Janowicz
    • Rafał Janowicz
    2023 Full text Ciepłownictwo, Ogrzewnictwo, Wentylacja

    Budynki szpitalne zwyczajowo projektowane są z uwzględnieniem standardowego obłożenia usługami medycznymi. Wystąpienie zdarzenia masowego, takiego jak katastrofa naturalna, konflikt militarny czy epidemia sprawia, że liczba osób wymagających hospitalizacji gwałtownie wzrasta, przekraczając możliwości działania szpitali w sposób prawidłowy. Analiza historii pandemii SARS-CoV-2 wykazuje, że większość systemów ochrony zdrowia nie była przygotowana na nadprogramowe ob- ciążenie, stąd wprowadzane rozwiązania poszerzenia struktury szpitalnej miały często charakter eksperymentalny. W artykule przedstawiono awaryjne realizacje architektoniczne obiektów tymczasowych w warunkach pandemii, jakie miały miejsce w Polsce i na świecie. Jako uszczegółowienie tematu przedstawiono problematykę polskiego kontekstu prawnego do- stosowania istniejących oddziałów szpitalnych do sytuacji za- grożenia epidemiologicznego. Celem artykułu jest potwierdzenie tezy o konieczności analizy pod względem architektonicznym i inżynierskim rozwiązań budowlanych zastosowanych w walce z pandemią SARS-CoV-2, aby zebrane dane umożliwiły opracowanie wytycznych przydatnych w planowaniu awaryjnej zabudowy medycznej w przypadku wystąpienia kolejnego kryzysu epidemiologicznego.

  • Bacterial cellulose vs. bacterial cellulose nanocrystals as stabilizer agents for O/W pickering emulsions
    • Agata Sommer
    • Hanna Staroszczyk
    2023 Full text FOOD HYDROCOLLOIDS

    The growing interest in Pickering emulsions in functional food systems resulted in the need to find suitable stabilizers for them. The work considers the use of bacterial cellulose for this purpose, and its aim was to compare the properties of disintegrated bacterial cellulose, before and after freeze-drying, and its nanocrystals obtained using H2SO4 under variable of time and concentration conditions. The structure of nanocrystals obtained with 30% acid was found to be still similar to that of parent cellulose, while the structure of nanocrystals obtained with 65% acid showed allomorphic transformation and the cellulose sulfates formation, regardless of the acid treatment time. Unlike nanocrystals obtained with 65% acid, those obtained with 30% acid as well as native bacterial cellulose ensured the high stability of O/W emulsion containing up to 20% olive oil. Effective stabilization of emulsions with the addition of nanocrystals obtained with the use of 30% acid was ensured by their strong surface charge density due to the presence of negatively charged sulfate groups.

  • Badania charakterystyki obciążeń oddziałujących na modułowe urządzenie dylatacyjne w pasie ruchu ciężkiego autostrady A8
    • Mikołaj Binczyk
    • Krzysztof Żółtowski
    2023 Full text Materiały Budowlane

    Przedstawiono badania urządzenia dylatacyjnego typu nożycowego. Dokonano statycznych i dynamicznych pomiarów odkształceń oraz przemieszczeń konstrukcji nożyc na najbardziej obciążonym pasie autostrady A8. Określono wpływ oddziaływania dynamicznego oraz sporządzono histogramy obciążeń i współczynników przewyższenia dynamicznego na podstawie pomiarów ciągłych w okresie nasilonego ruchu. Wskazano przyczyny degradacji urządzenia. Odniesiono się krytycznie do procedur badawczych dotyczących certyfikacji urządzeń dylatacyjnych.

  • Badania eksperymentalne i analiza numeryczna sklepień ceglanych. Wzmocnienie sklepień z wykorzystaniem struktur tensegrity.
    • Michał Gołębiewski
    2023 Full text

    Celem pracy jest opracowanie wzmocnienia zabytkowych sklepień murowych prętowo-cięgnowymi strukturami tensegrity. W tym celu przeanalizowano zagadnienia uszkodzeń, analizy oraz wzmacniania kopuł i sklepień murowych. W kolejnej części rozprawy przedstawiono prace badawczo-rozwojowe zakończone skutecznym wdrożeniem typoszeregu hal namiotowych o konstrukcji prętowo-cięgnowej typu tensegrity. Przeprowadzono badania dynamiczne oraz statyczne sklepienia kolebkowego w skali technicznej oraz jednej z hal namiotowych. Naturalnym połączeniem tych prac jest zaproponowany w rozprawie system wzmocnienia sklepień ceglanych z zastosowaniem struktur tensegrity. System ten został przebadany numerycznie oraz doświadczalnie na fizycznym i numerycznym modelu sklepienia kolebkowego. W pracy przedstawiono też serię symulacji numerycznych wzmocnionego strukturą tensegrity sklepienia o bardziej złożonej geometrii w rzeczywistych wymiarach zaczerpniętych z literatury. W ten sposób wykazano przydatność proponowanego rozwiązania do innych typów sklepień. Zaproponowany system wzmocnienia sklepień strukturami tensegrity ma cechy, które wyróżniają go na tle innych stosowanych obecnie sposobów wzmacniania i naprawy sklepień.

  • Badania eksperymentalne i numeryczne zachowania się zbiorników stalowych poddanych wstrząsom górniczym i sejsmicznym
    • Daniel Burkacki
    2023 Full text

    W niniejszej dysertacji opisano wyniki kompleksowych badań zachowania się zbiorników stalowych poddanych wstrząsom górniczym i umiarkowanym trzęsieniom ziemi. Badania prowadzono dla dwóch zbiorników rzeczywistych zlokalizowanych na terenie Polski. W pierwszym etapie badań przeprowadzono badania eksperymentalne na specjalnym stanowisku laboratoryjnym dla modeli doświadczalnych zbiorników. Badania prowadzono dla różnego poziomu wypełnienia obiektów substancją magazynowaną (całkowicie wypełnione, częściowo wypełnione i puste). W ramach tych badań wykonano testy impulsowe, testy sweep-sine, testy sejsmiczne i parasejsmiczne oraz testy zniszczeniowe. W drugim etapie badań przeprowadzono analizy numeryczne z wykorzystaniem MES dla modeli rzeczywistych zbiorników. Również te badania przeprowadzono dla różnego poziomu wypełnienia obiektów. W ramach tych badań wykonano analizy modalne, kompleksowe numeryczne testy sejsmiczne i parasejsmiczne (dla jednorodnego i niejednorodnego wymuszenia dynamicznego) oraz testy zniszczeniowe. Wyniki otrzymane z badań eksperymentalnych i numerycznych pokazały, iż poziom wypełnienia wpływa w sposób znaczny na wartości parametrów dynamicznych badanych obiektów oraz ma istotny wpływ na dynamiczne zachowanie się zbiorników.

  • Badania eksperymentalne transformatora hybrydowego jako kondycjonera napięcia w sieciach typu TN
    • Wojciech Matelski
    • Ryszard Strzelecki
    2023 Full text Przegląd Elektrotechniczny

    Artykuł dotyczy układu dystrybucyjnego transformatora hybrydowego (DTH) przeznaczonego do zastosowania w sieciach typu TN. Opisano w nim sposoby podłączenia przewodu neutralnego do układu DTH. W dalszej części artykuł zawiera opis skonstruowanego modelu laboratoryjnego o mocy 16 kVA wraz z zastosowanym algorytmem sterowania. Ponadto przedstawiono wyniki badań eksperymentalnych, ze szczególnym uwzględnieniem oceny dokładności stabilizacji napięcia obciążenia

  • Badania nad rozdzielaniem grupowym i analityką składu grupowego olejów bazowych i smarowych, zwłaszcza o szerokim zakresie polarności składników
    • Paulina Dyguła
    2023 Full text

    Rozprawa to studia i badania nad rozdzielaniem i analityką składu grupowego olejów bazowych i smarowych o szerokim zakresie polarności składników. Studium literatury wykazało brak metodyk badania udziału frakcji naftowej i roślinnej w takich olejach oraz nieadekwatność w tym celu HPLC. Pierwsza część pracy to badania nad opracowaniem wielokrotnie zastosowanej w praktyce terenowej metodyki i wyposażenia dla zastosowania fluorescencji w świetle UV 365 nm do przesiewowych terenowych badań olejów smarnych pilarek oraz laboratoryjnej procedury oceny obecności i zawartości naftowej/roślinnej frakcji w oleju z zastosowaniem: fluorescencji, spektrometrii UV, FT-MIR, szczególnie, NP-TLC. Druga część to badania nad opracowaniem procedury grupowego rozdzielania i analityki składu grupowego olejów o szerokim zakresie polarności składników techniką TLC-FID jako separacyjno-analityczną techniką rozdzielania i oznaczania składu grupowego olejów z wykorzystaniem techniki NP-TLC z adsorbentem impregnowanym solą berberyny (po udoskonaleniu metodyki impregnacji) w obszernych badaniach pilotowych. Wyniki i wnioski z badań mogą mieć znaczenie w analityce składu grupowego i kontroli technicznej wszystkich rodzajów olejów bazowych i smarowych, w monitoringu zanieczyszczenia środowiska, jak również w analityce żywności.

  • Badania nieniszczące mostu jako podstawa do oceny jego stanu na potrzeby realizacji przejazdu ponadnormatywnego
    • Andrzej Kozakiewicz
    • Mikołaj Miśkiewicz
    • Łukasz Pyrzowski
    • Bartosz Sobczyk
    2023 Full text

    Zagadnieniami związanymi z analizą możliwości realizacji przejazdów ponadnormatywnych przez obiekty mostowe zajmują się zespoły inżynierskie i naukowe na całym świecie. Wiele z analiz udaje się wykonać przy użyciu standardowych i typowych metod. Jest jednak grupa obiektów, dla których wymagane jest podejście indywidualne. Dla nich dopiero zaprojektowanie i zrealizowanie indywidualnie dobranego planu badawczego jest jedyną możliwością oceny czy przejazd ponadnormatywny o zdefiniowanych parametrach nie spowoduje awarii obiektu. W referacie przedstawiono metodykę postępowania, w wyniku którego możliwe było zezwolenie na przejazd transportu ponadnormatywnego o masie ponad 300 t po żelbetowym dwuprzęsłowym moście, którego nośność określono na 30 t. W celu oceny nośności mostu przeprowadzono szczegółowe oględziny, inwentaryzację, badania w trakcie próbnego obciążenia, polowe i laboratoryjne badania betonu, lokalizację i inwentaryzację zbrojenia oraz obliczenia statyczno-wytrzymałościowe. Co istotne most poddano badaniom podczas przejazdu, dzięki którym możliwa była eksperymentalna ocena pracy konstrukcji oraz zgodności deklaracji przewoźnika względem rzeczywistej masy transportu ponadnormatywnego.

  • Badania skuteczności ochrony katodowej zbiornika CWU typu HPMD-01.02.00
    • Krzysztof Żakowski
    • Tadeusz Sonneck
    • Kazimierz Darowicki
    2023

    Zbadano skuteczność ochrony katodowej wewnętrznej powierzchni zbiornika realizowanej w technologii z zewnętrznym źródłem prądu, z zastosowaniem dwóch typów tytanowych anod polaryzacyjnych.

  • Badania wpływu imperfekcji na rozkład obciążeń stabilizujących stężoną kratownicę
    • Marcin Krajewski
    2023

    Praca poświęcona jest analizom numerycznym stateczności i nośności stalowej kratownicy płaskiej. Konstrukcje tego typu często stosowane są jako przekrycia dachowe wielkogabarytowych hal stalowych i innych obiektów budowlanych. Charakteryzują się one dużą nośnością i sztywnością w swojej płaszczyźnie, przy czym istotny wpływ zarówno na ich obciążenie krytyczne, jak i graniczne, mają stężenia. W pracy badano wpływ sztywności stężeń, usytuowanych w płaszczyźnie prostopadłej do płaszczyzny kraty, na nośność wyboczeniową konstrukcji. W tym celu, dla modelu powłokowego badanej kratownicy, przerowadzono liniowe analizy stateczności (LBA). W pracy przedstawiono rezultaty analiz nieliniowych (GMNIA) dla konstrukcji z imperfekcjami geometrycznymi w formie postaci wyboczenia oraz w formie łukowej krzywizny, zalecanej przez europejskie przepisy normowe. Dla wybranych przypadków przedstawiono zależności pomiędzy obciążeniem kratownicy a reakcjami w sprężystych stężeniach. W pracy zaprezentowano również porównanie pomiędzy obciążeniem stabilizującym kratownicę, wyznaczonym na podstawie obowiązujących norm, oraz reakcjami w sprężystych podporach bocznych uzyskanymi na podstawie analiz numerycznych.

  • Badanie właściwości wytrzymałościowych wahaczy węglowych
    • Jakub Giedrewicz
    2023

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  • Badanie wpływu parametrów gruntu na obciążalność prądową długotrwałą kabli elektroenergetycznych
    • Filip Ratkowski
    2023 Full text

    Jednym z najważniejszych czynników wpływających na obciążalność prądową długotrwałą linii kablowych, poza przekrojem żyły roboczej, są parametry gruntu, w którym kable zostały ułożone. W celu poprawy odprowadzania ciepła z kabli, ziemię rodzimą zastępuje się najczęściej betonitem, czyli mieszaniną piaskowo-cementową, która ma mniejszą rezystywność cieplną w warunkach mniejszej wilgotności masowej od większości gruntów. W niniejszej rozprawie doktorskiej przedstawiono analizy numeryczne oraz badania eksperymentalne mające na celu sprawdzenie możliwości zwiększenia obciążalności prądowej długotrwałej linii kablowych. Omówiono zjawisko migracji wilgoci w pobliżu kabli, parametry wypełnień kontrolowanych, w tym betonitu oraz aspekty związane z wymianą ciepła w rurowych przepustach kablowych. Część analityczna rozprawy skupiona jest na wykazaniu stosowalności niekonwencjonalnych technik zwiększenia obciążalności linii kablowych, do których należą: zwiększenie średnicy przepustów rurowych wykorzystywanych przy układaniu kabli technologią bezwykopową oraz ponadnormatywny przekrój wypełnienia kontrolowanego (betonitu). Dla tej ostatniej przedstawiono przykładową analizę kosztową. W części eksperymentalnej przedstawiono charakterystykę rezystywności cieplnej betonitu w zależności od temperatury i wilgotności, wykazując poprawę odprowadzania ciepła z linii kablowych przy określonych poziomach wilgotności. Przedstawiono również wyniki trwającego 234 dni eksperymentu, polegającego na zbadaniu rozkładu przestrzennego wilgotności i temperatury wokół eksperymentalnego modelu linii kablowej. Porównano wyniki ułożenia linii kablowej w betonicie oraz przy wykorzystaniu nowej propozycji wypełnienia kontrolowanego, które miało na celu utrzymanie stałej wilgotności tego wypełnienia wokół linii kablowej. Zaproponowane w rozprawie metody zwiększenia obciążalności prądowej długotrwałej linii kablowej mogą być wykorzystane w praktyce.

  • Balanced Spider Monkey Optimization with Bi-LSTM for Sustainable Air Quality Prediction
    • Chelladurai Aarthi
    • Varatharaj Jeya Ramya
    • Przemysław Falkowski-Gilski
    • Parameshachari Bidare Divakarachari
    2023 Full text Sustainability

    A reliable air quality prediction model is required for pollution control, human health monitoring, and sustainability. The existing air quality prediction models lack efficiency due to overfitting in prediction model and local optima trap in feature selection. This study proposes the Balanced Spider Monkey Optimization (BSMO) technique for effective feature selection to overcome the local optima trap and overfitting problems. The air quality prediction data were collected from the Central Pollution Control Board (CPCB) from four cities in India: Bangalore, Chennai, Hyderabad, and Cochin. Normalization is performed using Min-Max Normalization and fills the missing values in the dataset. A Convolutional Neural Network (CNN) is applied to provide deep representation of the input dataset. The BSMO technique selects the relevant features based on the balancing factor and provides the relevant features for the Bi-directional Long Short-Term Memory (Bi-LSTM) model. The Bi-LSTM model provides the time series prediction of air quality for four cities. The BSMO model obtained higher feature selection performance compared to existing techniques in air quality prediction. The BSMO-BILSTM model obtained 0.318 MSE, 0.564 RMSE, and 0.224 MAE, whereas Attention LSTM reached 0.699 MSE, 0.836 RMSE, and 0.892 MAE. Our solution may be of particular interest to various governmental and non-governmental institutions focused on maintaining high Quality of Life (QoL) on the local or state level.

  • Ball milling treatment of Mn3O4 regulates electron transfer pathway for peroxymonosulfate activation
    • Huan Liu
    • Xiaohui Dai
    • Lingshuai Kong
    • Chengji Sui
    • Zixuan Nie
    • Yang Liu
    • Bin Cai
    • Shou-Qing Ni
    • Grzegorz Boczkaj
    • Jinhua Zhan
    2023 CHEMICAL ENGINEERING JOURNAL

    Heterogeneous metal catalysts have attracted considerable interest in advanced oxidation processes (AOPs) for wastewater treatment by activating peroxymonosulfate (PMS). However, it remains challenging to the rational design of efficient reaction pathway for high-performance contaminants removal by regulating the inherent structure of metal oxides. Herein, a high-energy ball milling method was employed to modulate the electronic structure of hausmannite (denoted as BM Mn3O4), which achieved the switching of singlet oxygen into electron transfer process (ETP)-dominated activation of PMS for efficient removal of bisphenol A - an emerging organic pollutant. The reaction pathway was evidenced through galvanic oxidation process, electrochemical techniques, and in-situ Raman spectroscopy, confirming the electrons transferred from pollutants to metastable PMS* complex with BM Mn3O4 serving as electron shuttle. The ETP mechanism was verified to be closely correlated with decreased eg occupancy of Mn in BM Mn3O4, offering high spatial overlapping with O 2p orbital in PMS for generating PMS* complex. Benefitting from the fine-tuned ETP, BM Mn3O4/PMS system showed enhanced intrinsic activity, higher PMS utilization efficiency, and practical applicability for selective oxidation of electron-rich pollutants. This study provided new insights into rational design of reaction-oriented catalysts for environmental engineering.

  • Band engineering of BiOBr based materials for photocatalytic wastewater treatment via advanced oxidation processes (AOPs) – A review
    • Zohaib Saddique
    • Muhammad Imran
    • Ayesha Javaid
    • Shoomaila Latif
    • Nazim Hussain
    • Przemysław Kowal
    • Grzegorz Boczkaj
    2023 Full text Water Resources and Industry

    Semiconductor based photocatalysts have been an efficient technology for water and wastewater remediation, addressing the concepts of green chemistry and sustainable development. Owing to narrow and suitable band structure, BiOBr is a promising candidate for efficient wastewater treatment via photocatalysis. Enhancement of photocatalytic properties can be obtained by various techniques like doping, element rich strategy, facet engineering, and defect control. This review primarily focuses on the band engineering of single BiOBr, its binary, ternary composites and their applications in degradation of hazardous pollutants in wastewater. Moreover, current challenges and future perspectives were discussed along with concluding comments.

  • Band Gap Engineering toward Semimetallic Character of Quinone-Rich Polydopamine
    • Adrian Olejnik
    • Karol Olbryś
    • Jakub Karczewski
    • Jacek Ryl
    • Robert Bogdanowicz
    • Katarzyna Siuzdak
    2023 Full text Journal of Physical Chemistry C

    Semiconductor|melanin interfaces have received increasingly more attention in the fields of photocatalysis and applied electrochemistry because of their facile synthesis, unique electrical properties, and strong capability toward photosensitization. In this work, we describe the electropolymerization of quinone-rich polydopamine (PDA) on the surface of hydrogenated TiO2 nanotubes with enhanced photoactivity in the visible spectrum. PDA is deposited uniformly on the nanotube walls, and the chemical structures of the resulting PDA layer strongly depend on the pH of the supporting electrolyte. The film thickness varies in the range of 2–8 nm depending on the number of electropolymerization cycles. Optical and electrochemical experiments coupled with density functional theory simulations revealed strong evidence of a semimetallic character of the junction with a broad distribution of midgap surface states induced by PDA. As a result of the nanotube modification, a 20-fold increase in the photocurrent response is observed. Quantum efficiency measurements show that the enhancement occurs mainly at wavelengths between 500 and 550 nm. Additionally, nonlinear electrochemical impedance spectroscopy experiments strongly suggest that, in the TiO2|PDA junction, PDA behaves as a set of redox mediators distributed at the surface rather than as a semiconducting polymer. This concept might be crucial for understanding the electronic properties of semiconductor|melanin junctions.

  • Bandwidth Dependence of the Propagation Channel in Circular Metallic BAN Environments
    • Manuel M. Ferreira
    • Filipe D. Cardoso
    • Sławomir Ambroziak
    • Luis M. Correia
    2023 Full text IEEE Access

    In this paper, the bandwidth dependence of the propagation channel for Body Area Networks (BANs) in circular metallic environments is addressed and models are proposed to evaluate the appropriate short-term fading margins that should be considered as a function of the system bandwidth. The deployment of BANs in metallic indoor environments, such as ships, factories, warehouses and other similar environments, involves additional challenges compared to other indoor environments due to the specific propagation effects in this type of environments (i.e., with strong reflections). No studies of this kind and for this type of environment can be found in literature, giving the motivation for this work. Bandwidth dependent values of delay spread are also presented and discussed. It is observed that for a system bandwidth up to 100 MHz the fading depth is composed of three main stages, with the transitions between these stages being associated with the system ability to discriminate arriving rays at the receiver. Average values of fading depth are 16.4, 13.2 and 11.0 dB for stages 1, 2 and 3, respectively, the difference between consecutive stages ranging between 2.2 to 3.2 dB. For a system bandwidth larger than 100 MHz, the fading depth decreases with an increasing system bandwidth, with an average decay rate close to 3 dB per 100 MHz bandwidth, being about 2 dB for system bandwidths above 400 MHz.

  • Bandwidth-Controllable Third-Order Band Pass Filter Using Substrate Integrated Full- and Semi-Circular Cavities
    • Nrusingha Pradhan
    • Adam Kozieł
    • Rusan Kumar Barik
    • Anna Pietrenko-Dąbrowska
    2023 Full text SENSORS

    The article presents a novel circular substrate integrated waveguide (SIW) bandpass filter (BPF) with controllable bandwidth. The proposed BPF is configured using two microstrip feedlines, semi- circular SIW cavities, capacitive slots, and inductive vias. The circular cavity is bisected into two halves, with the two copies thereof being cascaded. Two bisected and cascaded structures obtained this way are subsequently connected back-to-back. Finally, by introducing two inductive vias to the circular center cavity, a transmission zero is generated. In order to examine the design concept, a coupling matrix is generated. To demonstrate the theory a third-order BPF is realized, fabricated, and experimentally validated. The BPF prototype features a wide passband of 8.7 %, a low insertion loss of 1.1 dB, and a stopband of 1.5 f0 with a rejection level better than 20 dB.

  • Battery Technologies in Electric Vehicles: Improvements in Electric Battery Packs
    • Parham Mohseni
    • Oleksandr Husev
    • Dmitri Vinnikov
    • Ryszard Strzelecki
    • Enrique Romero-Cadaval
    • Igor Tokarski
    2023 IEEE Industrial Electronics Magazine

    Restrictions on fossil fuels and related environmental pollution issues motivate many organizations and countries to set their focus on electric vehicles (EVs) rather than conventional internal combustion engine vehicles [1], [2]. EVs require an energy storage system to store converted electric power in another form of energy and then reconvert the stored energy to electric power whenever it is required. The energy stored can be converted to electric energy for various uses, such as movement, lighting, and heating (although accessories are supplied by a 12-V auxiliary battery; the auxiliary battery is supplied by the main battery pack or by recuperative energy). Fortunately, many electrical energy storage technologies are available, with some offered commercially while others are in the research and development stage [3], [4]. Electrochemical energy storage systems use various technologies. Energy storage systems, the heart of EVs, are composed of battery cells, battery modules, and a battery pack. Researchers work on various sections of battery packs to improve their performance [7]. These sections are illustrated in Figure 1. As shown in the figure, some EV battery technology developers are studying chemical materials to increase the capacity, power, energy density, safety, and cell voltage. In the past century, the most common batteries for EV applications were Pb–acid and Ni-based batteries [8]. In current use, Li-ion-based batteries are at the top.

  • BAZYLIKA pw. ŚW. MIKOŁAJA W GDAŃSKU. PRZYKŁAD MONITORINGU I DIAGNOSTYKI ZABYTKOWYCH OBIEKTÓW KUBATUROWYCH
    • Maciej Niedostatkiewicz
    • Tomasz Majewski
    2023

    W artykule opisano przypadek monitorowania stanu technicznego zabytkowego budynku sakralnego po wystąpieniu awarii oraz w trakcie prowadzenia prac remontowych. W celu monitorowania stanu budynku, bezpiecznego prowadzenia prac diagnostycznych, rozpoznania przyczyn awarii oraz bezpiecznego prowadzenia prac remontowych opracowano szczegółowy Program monitorowania obiektu, który został wdrożony do realizacji, funkcjonuje i stanowi źródło cennych danych wykorzystywanych do oceny aktualnego stanu obiektu.

  • Bending analysis of functionally graded nanoplates based on a higher-order shear deformation theory using dynamic relaxation method
    • M. E. Golmakani
    • Mohammad Malikan
    • S. Golshani Pour
    • Victor Eremeev
    2023 Full text CONTINUUM MECHANICS AND THERMODYNAMICS

    In this paper, bending analysis of rectangular functionally graded (FG) nanoplates under a uniform transverse load has been considered based on the modified couple stress theory. Using Hamilton’s principle, governing equations are derived based on a higher-order shear deformation theory (HSDT). The set of coupled equations are solved using the dynamic relaxation (DR) method combined with finite difference (FD) discretization technique for clamped and simply-supported boundary conditions. Finally, the effects of aspect ratio, thickness-to-length ratio, transverse load, boundary conditions, and length scale parameter are studied in detail. The results showed that by rising the length scale-to-thickness ratio, the influence of the grading index on the deflection decreased.

  • Bending Moment Control and Weight Optimization in Space Structures by Adding Extra Members in the Optimal Locations
    • Ahmed Manguri
    • Najmadeen Saeed
    • Marcin Szczepański
    • Robert Jankowski
    2023 Full text Advances in Science and Technology Research Journal

    This paper investigates the reduction of bending moment in critical members by adding some extra members in the optimum location. Instead of enlarging the size of members to resist the moment, eight additional members are added in the optimum location to reduce the bending moment in the critical members. The total weight of the proposed structure with extra members is less than that of the original structure that resists the induced bending moment. Moreover, the location of the additional bars significantly reduces the nodal displacements. This paper investigates the effect of placing extra members on vertically and/or horizontally loaded egg-shaped single-layer frames. An egg-shaped structure is designed based on the maximum induced moment; in such frames, the bending moment is the dominant internal force. Then some extra members are suggested to be added to the structure to reduce the maximum bending moment to the lowest possible value; thus, the designed cross-sectional area is minimized. Furthermore, the optimized structure’s total weight and shape deformation is less than the ordinary structure’s. The study results show that the extra bars’ location depends on the loadings’ direction. Moreover, the weight of the horizontally loaded egg-shaped structure can be optimized by up to 28%. The results were verified by MATLAB and SAP2000 software