2022 - Repozytorium publikacji - Politechnika Gdańska

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A model of the response of the MGS-6 gravity sensor to tilting
- Krzysztof Pyrchla
- Małgorzata Pająk
- Julia Gołyga
- Jerzy Pyrchla
2022 Pełny tekst MEASUREMENT
The reliable interpretation of the measurements made by the Micro-g marine gravimetric system (MGS-6) depends on how the temporary changes of the scale coefficients such as gravimeter scale factor, vertical cross-coupling (VCC) effect, tiltmeter cross and tiltmeter long are compensated for during the signal analysis. The listed coefficients cannot be determined from readings during the measurements or by analysing the final data. The method presented here can be used to periodically check individual scale factors before starting shipborne measurements. This article focuses on determining the scale coefficients of the gravimeter: VCC effect, tiltmeter cross and tiltmeter long based on the MGS-6 gravity sensor's response to tilt. An unique non-linear model of Lacoste&Romberg gravimeter response to tilt was developed. In this paper, the measurement of the tilt angle of the object based on the photogrammetric elaboration of metric photographs is presented, using the principles of one-image photogrammetry.
A natural deep eutectic solvent - protonated L-proline-xylitol - based stationary phase for gas chromatography
- Malwina Momotko
- Justyna Łuczak
- Andrzej Przyjazny
- Grzegorz Boczkaj
2022 Pełny tekst JOURNAL OF CHROMATOGRAPHY A
The paper presents a new kind of stationary phase for gas chromatography based on deep eutectic solvents (DES) in the form of a mixture of L-proline (protonated with hydrochloric acid) as a hydrogen bond acceptor (HBA) and xylitol as a hydrogen bond donor (HBD) in a molar ratio of HBA:HBD 5:1. DES immobilized on a silanized chromatographic support was tested by gas chromatography (GC) in order to determine its resolving power for volatile organic compounds. Studies have demonstrated the suitability of this type of DES as a stationary phase for GC. The Rohrschneider-McReynolds constants were determined for the synthesized DES, revealing that it is a polar stationary phase (Σ(ΔI) = 1717). The selectivity of DES is influenced by the presence of hydroxyl groups in the xylitol structure capable of forming hydrogen bonds of a donor nature and the proton acceptor properties of the protonated L-proline structure. The presence of additional interactions is brought about by the presence of the carboxyl group. As a result, the retention of alcohols is several times higher (200-670%) than the expected value based on their boiling points. A significant increase in retention (400-970%) was also found for pyridine derivatives. The developed DES stationary phase is characterized by very good repeatability of retention and stability (up to 140°C). The efficiency of the prepared columns (6300-11300 theoretical plates/m) and the selectivity of the DES stationary phase are competitive with the commercial products.
A New Approach to Assess Quality of Motion in Functional Task of Upper Limb in Duchenne Muscular Dystrophy
- Wiktoria Wojnicz
- Agnieszka Sobierajska-Rek
- Bartłomiej Zagrodny
- Michał Ludwicki
- Joanna Jabłońska-Brudło
- Katarzyna Forysiak
2022 Pełny tekst Applied Sciences-Basel
(1) Background: This study presents a new method for the motion quantitative analysis of Duchenne muscular dystrophy patients (DMD) performing functional tasks in clinical conditions. (2) Methods: An experimental study was designed to define how different levels of external mass (light and heavy) influence the performance of the upper limbs of a tested DMD and reference subject (RS) during horizontal movements (level of the waist) under natural conditions (NC) and passive manipulator conditions (PMC); the kinematic data and muscle activity of four chosen superficial muscles (EMG) were recorded. (3) Results: A piecewise linear multi-regression analysis revealed high statistically significant results (R2 ≥ 0.75) between the tested muscle activities and kinematic data in the tested DMD patient and RS. These results were used to define whether the neural control of the four tested muscles (processed EMG data) was correlated more with the displacement of the wrist joint or the center of mass of the tested upper limb while performing functional tests with a given external weight in a horizontal plane under NC or PMC. (4) Conclusions: The proposed approach can be used to estimate the contributions of the tested muscles to patients’ motion performance and define whether this contribution is correlated with the kinematics or dynamics of the tested arm
A New Critical Risk on the Block: Cyber Risks as an Example of Technical Knowledge Risks in Organizations
- Małgorzata Zięba
- Susanne Durst
- Martyna Gonsiorowska
2022 Pełny tekst
The breakout of the COVID-19 pandemic has intensified the appearance of many additional technical knowledge risks in organizations. Cyber risks in particular are becoming a great challenge for organizations. At the same time, academic research on cyber risks, their costs, consequences and ability of overcoming them is still scarce and fragmented. In order to fill this gap, the paper is aimed to identify different types of cyber risks that organizations face and to examine the organizations’ ability to handle those risks. The paper presents research results from a sample of 60 organizations, addressing questions such as: (i) What are the costs of cyber risks the organization has faced? (ii) What is the company ability to address these risks?, and (iii) What is the organization doing to minimize the impact of such risks? Data was collected by means of a questionnaire. This research study has allowed to identify the state of the art concerning cyber risks, which can bear severe consequences for organizations. The findings clearly show that not all organizations suffer from the same level of cyber risks but it is much related to their field of operations. Consequently, also the ability to manage these cyber risks is quite diversified among the examined companies. Research results are limited to a sample of 60 organizations and thus the findings should be taken with caution. The study provides useful insights for managers and owners of organizations in need of dealing with the cyber threats/attacks and other technical knowledge risks threatening their organizations. The paper is enriched with a number of sample solutions that they may apply to mitigate those risks.The paper lays the ground for a better understanding of technical knowledge risks, primarily cyber risks, to which organizations are increasingly exposed today. As such, the paper offers food for thought for researchers dealing with the topic of technical knowledge risks and organizational risk management in general.
A New Expression System Based on Psychrotolerant Debaryomyces macquariensis Yeast and Its Application to the Production of Cold-Active β-D-Galactosidase from Paracoccus sp. 32d
- Marta Wanarska
- Ewelina Krajewska-Przybyszewska
- Monika Wicka-Grochocka
- Hubert Cieśliński
- Anna Pawlak-Szukalska
- Aneta Białkowska
- Marianna Turkiewicz
- Tomasz Florczak
- Ewa Gromek
- Joanna Krysiak
- Natalia Filipowicz
2022 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
Yeasts provide attractive host/vector systems for heterologous gene expression. The currently used yeast-based expression platforms include mesophilic and thermotolerant species. A eukaryotic expression system working at low temperatures could be particularly useful for the production of thermolabile proteins and proteins that tend to form insoluble aggregates. For this purpose, an expression system based on an Antarctic psychrotolerant yeast Debaryomyces macquariensis strain D50 that is capable of growing at temperatures ranging from 0 to 30 ◦C has been developed. The optimal physical culture conditions for D. macquariensis D50 in a fermenter are as follows: temperature 20 ◦C, pH 5.5, aeration rate of 1.5 vvm, and a stirring speed of 300 rpm. Four integrative plasmid vectors equipped with an expression cassette containing the constitutive GAP promoter and CYC1 transcriptional terminator from D. macquariensis D50 were constructed and used to clone and express a gene-encoding cold-active β-D-galactosidase of Paracoccus sp. 32d. The yield was 1150 U/L of recombinant yeast culture. Recombinant D. macquariensis D50 strains were mitotically stable under both selective and non-selective conditions. The D. macquariensis D50 host/vector system has been successfully utilized for the synthesis of heterologous thermolabile protein, and it can be an alternative to other microbial expression systems.
A new factor LapD is required for the regulation of LpxC amounts and lipopolysaccharide trafficking
- Alicja Wieczorek
- Anna Sendobra
- Akshay M S
- Magdalena Sugalska
- Gracjana Klein-Raina
- Satish Raina
2022 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
Lipopolysaccharide (LPS) constitutes the major component of the outer membrane and is essential for bacteria, such as Escherichia coli. Recent work has revealed the essential roles of LapB and LapC proteins in regulating LPS amounts; although, if any additional partners are involved is unknown. Examination of proteins co-purifying with LapB identified LapD as a new partner. The purification of LapD reveals that it forms a complex with several proteins involved in LPS and phospholipid biosynthesis, including FtsH-LapA/B and Fab enzymes. Loss of LapD causes a reduction in LpxC amounts and vancomycin sensitivity, which can be restored by mutations that stabilize LpxC (mutations in lapB, ftsH and lpxC genes), revealing that LapD acts upstream of LapB-FtsH in regulating LpxC amounts. Interestingly, LapD absence results in the substantial retention of LPS in the inner membranes and synthetic lethality when either the lauroyl or the myristoyl acyl transferase is absent, which can be overcome by single-amino acid suppressor mutations in LPS flippase MsbA, suggesting LPS translocation defects in ΔlapD bacteria. Several genes whose products are involved in cell envelope homeostasis, including clsA, waaC, tig and micA, become essential in LapD’s absence. Furthermore, the overproduction of acyl carrier protein AcpP or transcriptional factors DksA, SrrA can overcome certain defects of the LapD-lacking strain.
A new method of wind farm active power curve estimation based on statistical approach
- Natalia Szewczuk-Krypa
- Piotr Kolendo
- Jakub Głuszek
- Mateusz Drop
- Jacek Aronowski
2022 Pełny tekst Przegląd Elektrotechniczny
The purpose of this paper is to solve the wind farm active power estimation problem, introducing the method which is based on a statistical approach and robust fitting. The proposed algorithm uses a statistical approach and compared to existing ones- includes a wind direction as well as the influence of turbine start-up procedure on the estimation. The results show that additional estimation inputs i.e. the wind direction and the turbine state, improve the accuracy of estimated power. Estimation root mean square error captured over three days never exceeded 2%
A new model of fuel spray shape at early stage of injection in a marine Diesel engine
- Joanna Grochowalska
- Piotr Jaworski
- Łuaksz Jan Kapusta
- Jerzy Kowalski
2022 Pełny tekst INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW
In the cylinders of a marine diesel engine, self-ignition occurs in very shortly time after the fuel injection into the combustion chamber. Therefore, the paper present was to develop a model of diesel fuel spray for the early stage of fuel spray for in marine diesel engine. There were taken into consideration the main aspects technical such as nozzle diameter of marine engine injector and backpressure in combustion chamber. In this work, laboratory experimental studies were carried out in order to determined parameters of fuel spray in early stage of injection in marine diesel engine. Optical measuring Mie scattering technique was used to record the fuel injection process. The working space was a constant volume chamber. The backpressure parameters in the constant volume chamber were the same as during the operation of the marine diesel engine. On the based on the experimental studies and important Hiroyasu and Arai models of fuel spray presented in literature was proposed new model of fuel spray parameters for marine diesel injector. In this work, proposed new model of the two main parameters described fuel spray evolution: new model of spray tip penetration and spray cone angle. New model propagation of fuel spray tip penetration in time was included the influenced of nozzle diameter and backpressure. The proposed model has a lower error, about 15%-34%, than the model of Hiroyasu and Arai. Moreover a new model of the evolution over time of the spray cone angle is developed. In the future research of fuel spray process must be taken influence of the fuel temperature. Diesel fuel has a different density and viscosity in dependence of fuel temperature. Therefore are predicted of the expansion about influence of fuel temperature, new model of fuel spray for a marine diesel engine. The main limitations occuring in the research are is it not possible to carry out the research while real operation marine diesel engine. Experimental test were carried out for a real fuel injector of a marine diesel engine. Design parameters and fuel injection parameters were selected on the basis of the actual one. In the literature, spray cone angle is defined as constant parameter for the specific preliminary data. A new model for the early stage of fuel spray of spray cone angle propagation in time has beed proposed. The early stage of fuel spray is especially important, because in this time comes in there to fuel self-ignition.
A new relevant membrane application: CO2 direct air capture (DAC)
- Roberto Castro Munoz
- Mohd Zamidi Ahmad
- Magdalena Malankowska
- Joaquín Coronas
2022 Pełny tekst CHEMICAL ENGINEERING JOURNAL
Since carbon dioxide (CO2) is the primary greenhouse gas emitted into the atmosphere due to human activities, strong research efforts have been developed towards capturing and decreasing its production. Unfortunately, specific processes and activities make it impossible to avoid CO2 emissions. Among the different strategies scientists propose for CO2 reduction, direct CO2 capture from the atmosphere, also known as direct air capture (DAC), represents a promising alternative in which sorbents have been mainly used. Recently, gas separation membranes have also been speculated to carry out such a separation, thanks to their smaller footprint and simpler setup and operation; however, their application remains a proposition in the field. This paper gives a perspective of the ongoing research and attempts of DAC applications via membrane separation and introduces the main membrane materials and types used for CO2 separation. Finally, the process considerations for DAC using membranes are stated to guide the new researchers in the field.
A non-linear direct peridynamics plate theory
- Konstantin Naumenko
- Victor Eremeev
2022 Pełny tekst COMPOSITE STRUCTURES
In this paper a direct non-local peridynamics theory for thin plates is developed. Peridynamic points are assumed to behave like rigid bodies with independent translation and finite rotation degrees of freedom. The non-local mechanical interaction between points is characterized by force and moment vectors. The balance equations including the linear momentum, the angular momentum and the energy are presented. Peridynamic deformation states of the plate are introduced including the actual bond vector (relative translation of two points within the bond) and the relative finite rotation tensor (actual relative orientation of two points in the bond). The corresponding power-conjugate bond force and bond moment states are derived. The framework to develop constitutive equations for the plate peridynamic states is addressed. Special cases of the theory including plates with zero drilling moments, membranes, soft interlayers as well as stiff plate layers with small relative rotations are considered.
A note on the affective computing systems and machines: a classification and appraisal
- Paweł Weichbroth
- Wiktor Sroka
2022 Pełny tekst Procedia Computer Science
Affective computing (AfC) is a continuously growing multidisciplinary field, spanning areas from artificial intelligence, throughout engineering, psychology, education, cognitive science, to sociology. Therefore, many studies have been devoted to the aim of addressing numerous issues, regarding different facets of AfC solutions. However, there is a lack of classification of the AfC systems. This study aims to fill this gap by reviewing and evaluating the state-of-the-art studies in a qualitative manner. In this line of thinking, we put forward a threefold classification that breaks down to desktop and mobile AfC systems, and AfC machines. Moreover, we identified four types of AfC systems, based on the features extracted. In our opinion, the results of this study can serve as a guide for future affect-related research and design, on the one hand, and provide a better understanding on the role of emotions and affect in human-computer interaction, on the other hand.
A novel approach exploiting properties of convolutional neural networks for vessel movement anomaly detection and classification
- Bartosz Czaplewski
- Mariusz Dzwonkowski
2022 Pełny tekst ISA TRANSACTIONS
The article concerns the automation of vessel movement anomaly detection for maritime and coastal traffic safety services. Deep Learning techniques, specifically Convolutional Neural Networks (CNNs), were used to solve this problem. Three variants of the datasets, containing samples of vessel traffic routes in relation to the prohibited area in the form of a grayscale image, were generated. 1458 convolutional neural networks with different structures were trained to find the best structure to classify anomalies. The influence of various parameters of network structures on the overall accuracy of classification was examined. For the best networks, class prediction rates were examined. Activations of selected convolutional layers were studied and visualized to present how the network works in a friendly and understandable way. The best convolutional neural network for detecting vessel movement anomalies has been proposed. The proposed CNN is compared with multiple baseline algorithms trained on the same dataset.
A novel approach for processing CaAlSiON glass-ceramics by spark plasma sintering: Mechanical and electrical properties
- Sharafat Ali
- Abbas Saeed Hakeem
- Mirva Eriksson
- Natalia Wójcik
2022 Pełny tekst JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
Lithium containing glassy materials can be used as solid electrolytes or electrode materials for lithium-ion batteries due to their high energy density. Conventional melt-quenched Ca11Al14Si16O49N10 glass powder containing 24 e/o N, doped with Li-ions (1, 3, and 6 wt. %) and sintered by spark plasma sintering technique (SPS) was studied. The benefits of using SPS to produce glass-ceramics are rapid heating rates compared to conventional consolidation techniques and tuning of properties, adjusting the temperature, holding time (closed to Tg temperature), heating rate (solidification), and pressure (densification) profile during the heat treatment using SPS. Pure glass and glass-ceramic were obtained under identical SPS conditions and compared with pristine oxynitride and soda-lime-silicate (float) glasses. XRD and SEM analysis confirmed that increasing the amount of Li increases the crystallinity in the glass matrix. Nano-indentation analysis showed a decreased hardness and reduced elastic modulus values with the addition of Li-ions. The direct current conductivity increases with the addition of Li due to the high mobility of Li-ions. However, the float glass sample doped with 6 wt.% of Li exhibits even higher values of D.C. conductivity, than the analogously doped Ca11Al14Si16O49N10 glass. The magnitude of activation energy (more than 1 eV) is typical for an ion hopping mechanism and the D.C. conduction mechanism is dominated by Li+ hopping.
A novel architecture of Web-GIS for mapping and analysis of echinococcosis in Poland
- Marcin Kulawiak
- Natalia Kulawiak
- Małgorzata Sulima
- Katarzyna Sikorska
2022 Pełny tekst Applied Geomatics
Echinococcosis is an infectious disease transferred through ingestion of food or water which have been contaminated with eggs of the Echinococcus tapeworm, which are spread by intermediate parasite hosts. Because the latter are primarily territorial, research related to diagnosis and prevention of echinococcosis requires investigation of environmental factors, which can be supported with the use of a Geographical Information System (GIS). In particular, since this type of research is usually performed by a team of medical researchers working individually with many patients, it can greatly benefit from the use of a Web-GIS, which provides remote access to data integration, storage and analysis tools. However, most existing Web-GIS solutions dedicated for disease mapping either exhibit limited functionality and interactivity (often due to the use of a thin-client approach), or are tied to a particular technological platform through a thick client based on a browser plugin. Moreover, few of the existing solutions provide user-friendly tools for data input, and none are directly integrated into the workflow of clinicians. This paper proposes a novel system architecture for Web-GIS dedicated to disease mapping, which attempts to optimize the use of client and server hardware resources while providing the user with a variety of analytic functionalities. The proposed architecture has been implemented in the form of a system for remote mapping and analysis of echinococcosis cases in Poland, which has been designed in cooperation with a major Polish hospital centre.
A Novel Cryptic Clostridial Peptide That Kills Bacteria by a Cell Membrane Permeabilization Mechanism
- Monika Szadkowska
- Michał Olewniczak
- Anna Kloska
- Elzbieta Jankowska
- Malgorzata Kapusta
- Bartosz Rybak
- Dariusz Wyrzykowski
- Wioletta Zmudzinska
- Artur Gieldon
- Aleksandra Kocot
- Anna-Karina Kaczorowska
- Łukasz Nierzwicki
- Joanna Makowska
- Tadeusz Kaczorowski
- Magdalena Płotka
2022 Pełny tekst Microbiology Spectrum
This work reports detailed characteristics of the antimicrobial peptide Intestinalin (P30), which is derived from the LysC enzyme of Clostridium intestinale strain URNW. The peptide shows a broader antibacterial spectrum than the parental enzyme, showing potent antimicrobial activity against clinical strains of Gram-positive staphylococci and Gram-negative pathogens and causing between 3.04 ± 0.12 log kill for Pseudomonas aeruginosa PAO1 and 7.10 ± 0.05 log kill for multidrug-resistant Acinetobacter baumannii KPD 581 at a 5 μM concentration. Moreover, Intestinalin (P30) prevents biofilm formation and destroys 24-h and 72-h biofilms formed by Acinetobacter baumannii CRAB KPD 205 (reduction levels of 4.28 and 2.62 log CFU/mL, respectively). The activity of Intestinalin is combined with both no cytotoxicity and little hemolytic effect against mammalian cells. The nuclear magnetic resonance and molecular dynamics (MD) data show a high tendency of Intestinalin to interact with the bacterial phospholipid cell membrane. Although positively charged, Intestinalin resides in the membrane and aggregates into small oligomers. Negatively charged phospholipids stabilize peptide oligomers to form water- and ion-permeable pores, disrupting the integrity of bacterial cell membranes. Experimental data showed that Intestinalin interacts with negatively charged lipoteichoic acid (logK based on isothermal titration calorimetry, 7.45 ± 0.44), causes membrane depolarization, and affects membrane integrity by forming large pores, all of which result in loss of bacterial viability.
A novel degree-hour method for rational design loading
- Andrii Radchenko
- Mykola Radchenko
- Dariusz Mikielewicz
- Roman Radchenko
- Andrii Andreev
2022 Pełny tekst PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART A-JOURNAL OF POWER AND ENERGY
Cooling degree-hours (CDH) received the broadest application in evaluation of the ambient air cooling efficiency in power engineering (engine intake air cooling systems) and air conditioning. The current CDH numbers are defined as a drop in air temperature multiplied by associated time duration of performance and their summarized annual number is used to estimate the annual effect achieved due to sucked air cooling in power plants based on combustion engines (fuel saving, power output increment) and in air conditioning (refrigeration energy generation according to needs). A majority of approaches to designing ambient air cooling systems is proceeding from the cooling capacity of the chillers selected to provide a maximum current or annual CDH number with corresponding maximum current or annual effect (additional energy produced or fuel consumption reduction) in site climate location. But such approaches lead to inevitable oversizing the chillers and cooling systems in the whole. The analysis of intake air cooling efficiency in site varying climatic conditions, accompanied by quite a simple numerical simulation, enabled to reveal the potential of its enhancement and evaluate numerically the results of each step of designing in logical sequence. The new approaches to cooling system rational designing were introduced, that enables to synthesize and substantiate innovative principal decisions to exclude unproductive waste of installed (design) cooling capacity in actual operation. The innovative findings of methodological approaches include the use of the rate of annual CDH number increment as an indicator for selecting the optimum and rational values of design cooling capacity. The optimum cooling capacity corresponds to maximum rate of summarized annual CDH increment and maximum level of thermal loading accordingly, which provides minimum sizes of the chiller. In reality, it is a minimum permissible value of cooling capacity of the chiller installed and the overall ambient air cooling system. The rational cooling capacity, that enables to achieve practically maximum value of annual CDH and avoid chiller oversizing, is determined as the second, local, maximum of the rate in the summarized annual CDH over the range above the first one, global, maximum. A rational design cooling capacity determined by applying the novel methodology allows to decrease the ambient air cooling system sizes by 15 to 20% compared with traditional methods.
A novel DEM-based pore-scale thermo-hydro-mechanical model
- Marek Krzaczek
- Michał Nitka
- Andrzej Tejchman-Konarzewski
2022
W warunkach nieizotermicznych ruch płynu w układzie porów i kapilar betonu jest silnie sprzężony z przenoszeniem ciepła. W takich warunkach pory i spękania ułatwiają wnikanie do betonu zewnętrznych czynników agresywnych, które degradują zarówno beton, jak i zbrojenie. Opracowano innowacyjny model termo-hydro-mechaniczny oparty na modelu DEM, aby szczegółowo śledzić frakcje cieczy/gazów w porach i pęknięciach pod kątem ich różnej geometrii, rozmiaru, lokalizacji i temperatury. Przydatność w pełni sprzężonego modelu termohydromechanicznego została zilustrowana przez symulację eksperymentu, w którym nasycona porowata próbka była poddana procesowi chłodzenia.
A novel hierarchically-porous diamondized polyacrylonitrile sponge-like electrodes for acetaminophen electrochemical detection
- Mattia Pierpaoli
- Chiara Giosuè
- Natalia Czerwińska
- Aneta Lewkowicz
- Maria Letizia Ruello
- Robert Bogdanowicz
- Bartłomiej Dec
- Paweł Jakóbczyk
2022 Pełny tekst ELECTROCHIMICA ACTA
A novel composite electrode material consisting of tangled fibrous polyacrylonitrile-based hierarchically-struc- tured nanocomposites has been produced by wet-spinning, carbonized and decorated with a carbon nano- architecture by microwave plasma-enhanced chemical vapor deposition and investigated as a metal-free electrode for the enhanced electrochemical detection of acetaminophen. Surprisingly, the hierarchical fiber ar- chitecture is the result of the synergistic action between surface etching, by the H2 plasma, and nanostructure formation, by the C- and CH- radicals, which significantly affect the porosity and electrochemical performance. Moreover, by simultaneously conducting fiber carbonization and surface functionalization, it is possible to dramatically reduce the manufacturing time and to confer an 18-fold increase of the acetaminophen detection sensitivity, due to the sp2-C defect-rich overgrown nanostructure, which represents a preferable site for the drug adsorption, as supported by the molecular dynamics simulation results. Because of the excellent performance, and the simple and scalable production method, the prepared composite is a promising candidate as a metal-free electrochemical sensor
A novel in vivo approach to assess strains of the human abdominal wall under known intraabdominal pressure
- Izabela Lubowiecka
- Katarzyna Szepietowska
- Agnieszka Tomaszewska
- Paweł Michał Bielski
- Michał Chmielewski
- Monika Lichodziejewska-Niemierko
- Czesław Kazimierz Szymczak
2022 Pełny tekst Journal of the Mechanical Behavior of Biomedical Materials
The study concerns mechanical behaviour of a living human abdominal wall. A better mechanical understanding of a human abdominal wall and recognition of its material properties is required to find mechanically compatible surgical meshes to significantly improve the treatment of ventral hernias. A non-invasive methodology, based on in vivo optical measurements is proposed to determine strains of abdominal wall corresponding to a known intraabdominal pressure. The measurement is performed in the course of a standard procedure of peritoneal dialysis. A dedicated experimental stand is designed for the experiment. The photogrammetric technique is employed to recover the three-dimensional surface geometry of the anterior abdominal wall at the initial and terminal instants of the dialysis. This corresponds to two deformation states, before and after filling the abdominal cavity with dialysis fluid. The study provides information on strain fields of living human abdominal wall. The inquiry is aimed at principal strains and their directions, observed at the level from -10% to 17%. The intraabdominal pressure related to the amount of introduced dialysis fluid measured within the medical procedure covers the range 11–18.5 cmH2O. The methodology leads to the deformation state of the abdominal wall according to the corresponding loading conditions. Therefore, the study is a step towards an identification of mechanical properties of living human abdominal wall.
A Novel Method for Intelligibility Assessment of Nonlinearly Processed Speech in Spaces Characterized by Long Reverberation Times
- Adam Kurowski
- Józef Kotus
- Piotr Odya
- Bożena Kostek
2022 Pełny tekst SENSORS
Objective assessment of speech intelligibility is a complex task that requires taking into account a number of factors such as different perception of each speech sub-bands by the human hearing sense or different physical properties of each frequency band of a speech signal. Currently, the state-of-the-art method used for assessing the quality of speech transmission is the speech transmission index (STI). It is a standardized way of objectively measuring the quality of, e.g., an acoustical adaptation of conference rooms or public address systems. The wide use of this measure and implementation of this method on numerous measurement devices make STI a popular choice when the speech-related quality of rooms has to be estimated. However, the STI measure has a significant drawback which excludes it from some particular use cases. For instance, if one would like to enhance speech intelligibility by employing a nonlinear digital processing algorithm, the STI method is not suitable to measure the impact of such an algorithm, as it requires that the measurement signal should not be altered in a nonlinear way. Consequently, if a nonlinear speech enhancing algorithm has to be tested, the STI—a standard way of estimating speech transmission cannot be used. In this work, we would like to propose a method based on the STI method but modified in such a way that it makes it possible to employ it for the estimation of the performance of the nonlinear speech intelligibility enhancement method. The proposed approach is based upon a broadband comparison of cumulated energy of the transmitted envelope modulation and the received modulation, so we called it broadband STI (bSTI). Its credibility with regard to signals altered by the environment or nonlinear speech changed by a DSP algorithm is checked by performing a comparative analysis of ten selected impulse responses for which a baseline value of STI was known.