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  • Lateral load resistance of piled raft foundation - A case study of District Jail, Saidu Sharif, Swat Pakistan
    • Irfan Jamil
    • Irshad Khan
    • Maaz Amjad
    • Mahmood Ahmad
    • Umar Farooq
    • Tayyaba Bibi
    2021 Pełny tekst International Journal of Applied Engineering Research (Netherlands)

    Piled raft foundations under lateral loads are usually designed as a pile group, ignoring the contribution of the raft to resisting the lateral loads. In this paper, a case study was performed to determine the raft's contribution to the lateral load resistance. This study analyzed a pile-supported reinforced concrete retaining wall for two different foundation conditions, i.e., pile group foundation and pile raft foundation. Pile group supported reinforced concrete retaining wall was analyzed by following the standard code practice while pile raft supported reinforced concrete retaining wall was analyzed with the help of up-to-the-minute finite element-based software, PLAXIS 3D. It was revealed that by considering the contribution of the raft in the pile raft foundation system subjected to lateral loads, a great deal of economy can be achieved in terms of the small diameter of piles, short pile lengths and less number of piles. The maximum moment on piles was decreased about 2.5-3 times while the maximum shear was decreased about 2-3 times. A decrease in demand also results in reducing the lateral deflection of piles to about 50 %.

  • Latest Insights on Novel Deep Eutectic Solvents (DES) for Sustainable Extraction of Phenolic Compounds from Natural Sources
    • Julio Serna-vázquez
    • Mohd Zamidi Ahmad
    • Grzegorz Boczkaj
    • Roberto Castro-Muñoz
    2021 Pełny tekst MOLECULES

    Phenolic compounds have long been of great importance in the pharmaceutical, food, and cosmetic industries. Unfortunately, conventional extraction procedures have a high cost and are time consuming, and the solvents used can represent a safety risk for operators, consumers, and the environment. Deep eutectic solvents (DESs) are green alternatives for extraction processes, given their low or non-toxicity, biodegradability, and reusability. This review discusses the latest research (in the last two years) employing DESs for phenolic extraction, solvent components, extraction yields, extraction method characteristics, and reviewing the phenolic sources (natural products, by-products, wastes, etc.). This work also analyzes and discusses the most relevant DES-based studies for phenolic extraction from natural sources, their extraction strategies using DESs, their molecular mechanisms, and potential applications.

  • LE STIME ECONOMICHE DELLA CIA E L’IMPREVEDIBILE FINE DELL’URSS
    • Luciano Segreto
    2021 Studi Storici

    In this article, we will analyze the debate that took place around the assessments that the CIA gave of the economic situation in the Soviet Union, a clearly decisive key to understanding the overall health of the main political-military opponent of the United States. The article will include the discussions that flared up in the American political establishment starting in 1990, after the fall of the Berlin Wall and the initial disorientation due to the loss of the historical adversary of the Cold War. Moreover, the positions taken by sovietologists in these discussions will be evaluated, as well as the role played in these debates by the analysis developed by Soviet economists in the 1980s. We will lastly consider the official response provided by the CIA (a response that, coming only in 2001, was actually rather slow to arrive), aimed essentially at confirming the correctness of its analyses and reiterating that its duties did not include that of predicting the collapse of the Soviet Union.

  • Leadership, culture, intellectual capital and knowledge processes for organizational innovativeness across industries: the case of Poland
    • Wioleta Kucharska
    2021 Pełny tekst Journal of Intellectual Capital

    Purpose – This study aims to present the overview of intellectual capital creation micro-mechanisms concerning formal and informal knowledge processes. The organizational culture, transformational leadership and innovativeness are also included in the investigation as ascendants and consequences of the focal relation of intellectual capital and knowledge processes. Design/methodology/approach – Based on a sample of 1,418 Polish knowledge workers from the construction, healthcare, higher education and information technology (IT) industries, the empirical model was developed using the structural equation modeling (SEM) method. Findings – The study exposes that the essence of transformational leadership innovativeness oriented is developing all intellectual capital components. To do so, leaders must support both formal and informal knowledge processes through the organizational culture of knowledge and learning. Furthermore, for best results of the knowledge transformation into intellectual capital, the learning culture must be shaped by both components: learning climate and acceptance of mistakes. Practical implications – Presented findings can be directly applied to organizations to enhance innovativeness. Namely, leaders who observe that the more knowledge is formally managed in their organizations, the less effective the knowledge exchange is-should put more effort into supporting informal knowledge processes to smoothly develop human and relational intellectual capital components. Shortly, leaders must implement an authentic learning culture, including the mistakes acceptance component, to use the full organizational potential to achieve intellectual capital growth. Intellectual capital growth is essential for innovativeness. Originality/value – This study presents the “big picture” of all intellectual capital creation micromechanisms linking transformational leadership with organizational innovativeness and explains the “knowledge paradox” identified by Mabey and Zhao (2017). This explanation assumes that intellectual capital components are created informally (i.e. human and relational ones) and formally (i.e. structural ones). Therefore, for best effects, both formal and informal knowledge processes, must be supported. Furthermore, this study exposes that the intensity of all explored micro-mechanisms is industry-specific

  • Leveraging spatio-temporal features for joint deblurring and segmentation of instruments in dental video microscopy
    • Efkleidis Katsaros
    • Anna Jezierska
    • Daniel Węsierski
    2021

    In dentistry, microscopes have become indispensable optical devices for high-quality treatment and micro-invasive surgery, especially in the field of endodontics. Recent machine vision advances enable more advanced, real-time applications including but not limited to dental video deblurring and workflow analysis through relevant metadata obtained by instrument motion trajectories. To this end, the proposed work addresses dental video deblurring and instrument segmentation in a Multi-task Learning fashion, leveraging spatio-temporal adaptive kernels via a recurrent design. The task-specific branches of our architecture employ the responses of those kernels to recover sharper video frames and yield the dental instrument segmentation mask. We demonstrate that the proposed method improves deblurring while retaining segmentation performance under a low computational footprint.

  • Licencjonowanie oprogramowania
    • Tomasz Boiński
    • Szymon Olewniczak
    2021 Pełny tekst

    Wolne i otwarte oprogramowanie przeżywa ostatnimi laty rozkwit. Co raz więcej przedsiębiorstw komercyjnych opiera rozwój swoich firm na otwartym oprogramowaniu. Zarówno mali, jak i duzi gracze mają świadomość komplikacji współczesnych systemów i niemożności samodzielnego ich rozwoju. Z pomocą przychodzi otwarte podejście do wytwarzania oprogramowania. Wymaga to jednak pewnego zrozumienia uwarunkowań prawnych, a w szczególności licencji, na jakich wydawane jest oprogramowanie. Niniejsze opracowanie ma na celu omówienie tychże uwarunkowań, odpowiada na pytanie dlaczego potrzebujemy licencji na oprogramowanie. Opisywane zostały również najważniejsze wg autorów licencje, oraz wskazuje, czym należy kierować się przy doborze licencji.

  • Lighting Design for the 21st Century Applied research in lighting practice
    • Karolina Zielińska-Dąbkowska
    2021 Pełny tekst ARC Lighting In Architecture

    For those who are unfamiliar with research, it’s important to know there are two categories. Fundamental (or basic) research and applied research. Basic research often discusses scientific ideas/theories, whereas, applied research explores testing these ideas in practice to develop technology or techniques. It’s applied research which most interests lighting practitioners. Great lighting design that creates a pleasant and beneficial user experience in any given space doesn’t just occur miraculously. Rather, it’s built on the designer’s insights and understanding, which comes from sound research and years of practice. This awareness comes from knowing the end users, as well as comprehending what’s best for them. In my view, there are three key research topics for the future of our lighting design profession that we should become familiar with. They are all based on the mounting research about daylight and artificial light and its impact on circadian relevance and biological stimulus. These are: (1) Environmental impact and light pollution, (2) Biophilic office design and (3) User oriented daylight integrated lighting (DIL). These topics have been demonstrated below by some pioneering project examples, where research has been performed to help derive outstanding results.

  • Light-Modulated Sunscreen Mechanism in the Retina of the Human Eye
    • Rafal Luchowski
    • Wojciech Grudzinski
    • Renata Welc
    • Maria Manuela Mendes Pinto
    • Alicja Sek
    • Jan Ostrowski
    • Łukasz Nierzwicki
    • Paweł Chodnicki
    • Miłosz Wieczór
    • Karol Sowinski
    • Robert Rejdak
    • Anselm G. M. Juenemann
    • Grzegorz Teresinski
    • Jacek Czub
    • Wieslaw Gruszecki
    2021 Pełny tekst JOURNAL OF PHYSICAL CHEMISTRY B

    The functioning of the human eye in the extreme range of light intensity requires a combination of the high sensitivity of photoreceptors with their photostability. Here, we identify a regulatory mechanism based on dynamic modulation of light absorption by xanthophylls in the retina, realized by reorientation of pigment molecules induced by trans–cis photoisomerization. We explore this photochemically switchable system using chromatographic analysis coupled with microimaging based on fluorescence lifetime and Raman scattering, showing it at work in both isolated human retina and model lipid membranes. The molecular mechanism underlying xanthophyll reorientation is explained in terms of hydrophobic mismatch using molecular dynamics simulations. Overall, we show that xanthophylls in the human retina act as “molecular blinds”, opening and closing on a submillisecond timescale to dynamically control the intensity of light reaching the photoreceptors, thus enabling vision at a very low light intensity and protecting the retina from photodegradation when suddenly exposed to strong light.

  • Linkages between services and manufacturing as a new channel for GVC development: Evidence from CEE countries
    • Aleksandra Kordalska
    • Magdalena Olczyk
    2021 Pełny tekst Structural Change and Economic Dynamics

    The goal of the paper is to verify a causal relationship between forward linkages from domestic services to manufacturing and the participation/position of a country in global value chains (GVCs) in selected Central and Eastern European economies. We observed a strong polarisation pattern: the Baltic countries along with the Czech Republic strengthen their positions and participation in GVCs by having a strong relationship between the financial sector and manufacturing, while Poland, Hungary, and Slovakia have solid linkages between transportation services and manufacturing. We also discover that the reverse relationship is significant.

  • Load capacity of steel-aluminium brackets under static and cyclic laboratory tests
    • Andrzej Ambroziak
    2021 Pełny tekst Archives of Civil Engineering

    The aim of the research is the laboratory investigation of steel-aluminium brackets employed to fasten lightweight curtain walls to building facilities. Static pressure, suction forces, and cyclic loads parallel to end plates (horizontal – to simulate wind influence) were applied in the study. The steel-aluminium brackets were tested on a reinforced concrete substrate made of C30/37 concrete class to simulate the real working conditions. Laboratory tests were performed to failure of the brackets or damage of anchoring fastened to the concrete elements. Additionally, the tensile capacity of stainless steel bolt connections screwed in aluminium profile was determined. The uniaxial tensile tests were performed for three length variants of the anchorage: 28 mm, 14 mm, and 7 mm of the stainless steel bars screw-in in threading aluminium profiles. In the course of cyclic tests, a hinge formed in the location of bolt connections made the change of the working character of steel-aluminium brackets. The cyclic tests also showed the danger of the strap aluminium profile displacement due to improper connection with the main aluminium profile. The paper is intended to provide scientists, civil engineers, and designers with an experimental assessment of mechanical properties of steel-aluminium brackets under static and cyclic loads.

  • Local material symmetry group for first- and second-order strain gradient fluids
    • Victor Eremeev
    2021 Pełny tekst MATHEMATICS AND MECHANICS OF SOLIDS

    Using an unified approach based on the local material symmetry group introduced for general first- and second-order strain gradient elastic media, we analyze the constitutive equations of strain gradient fluids. For the strain gradient medium there exists a strain energy density dependent on first- and higher-order gradients of placement vector, whereas for fluids a strain energy depends on a current mass density and its gradients. Both models found applications to modeling of materials with complex inner structure such as beam-lattice metamaterials and fluids at small scales. The local material symmetry group is formed through such transformations of a reference placement which cannot be experimentally detected within the considered material model. We show that considering maximal symmetry group, i.e. material with strain energy that is independent of the choice of a reference placement, one comes to the constitutive equations of gradient fluids introduced independently on general strain gradient continua.

  • Locust bean gum as green and water-soluble binder for LiFePO4 and Li4Ti5O12 electrodes
    • Paweł Jakóbczyk
    • Michał Bartmański
    • Ewelina Rudnicka
    2021 Pełny tekst JOURNAL OF APPLIED ELECTROCHEMISTRY

    Locust Bean Gum (LBG, carob bean gum) was investigated as an environmentally friendly, natural, and water-soluble binder for cathode (LFP) and anode (LTO) in lithium-ion batteries (Li-ion). For the frst time, we show LBG as an electrode binder and compare to those of the most popular aqueous (CMC) and conventional (PVDF) binders. The electrodes were characterized using TGA/DSC, the galvanostatic charge–discharge cycle test, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Thermal decomposition of LBG is seen to begin above 250 °C with a weight loss of about 60 wt% observed at 300 °C, which is sufcient to ensure stable performance of the electrode in a Li-ion battery. For CMC, weight loss at the same temperature is about 45%. Scanning electron microscopy (SEM) shows that the LFP–LBG system has a similar distribution of conductive carbon black particles to PVDF electrodes. The LTO–LBG electrode has a homogeneous dispersion of the electrode elements and maintains the electrical integrity of the network even after cycling, which leads to fast electron migration between LTO and carbon black particles, as well as ion conductivity between LTO active material and electrolyte, better than in systems with CMC and PVDF. The exchange current density, obtained from impedance spectroscopy fell within a broad range between 10−4 and 10−2 mA cm−2 for the LTO|Li and LFP|Li systems, respectively. The results presented in this paper indicate that LBG is a new promising material to serve as a binder.

  • Long-Term Impact of Wind Erosion on the Particle Size Distribution of Soils in the Eastern Part of the European Union
    • Lenka Lackóová
    • Jozefína Pokrývková
    • Jana Kozlovsky Dufková
    • Agnieszka Policht-Latawiec
    • Krystyna Michałowska
    • Jolanta Dąbrowska
    2021 Pełny tekst ENTROPY

    Wind erosion is the leading cause of soil degradation and air pollution in many regionsof the world. As wind erosion is controlled by climatic factors, research on this phenomenon isurgently needed in soil and land management in order to better adapt to climate change. In thispaper, the impact of wind erosion on the soil surface in relation to particle size distribution wasinvestigated. Changes in percentage of sand, silt and clay fractions based on historical KPP data(1961–1970), LUCAS data base (2009), and field measurements (2016) were analysed in five cadastralareas impacted by wind erosion (Záhorie Lowlands, Slovakia). With the use of GIS tools, models ofspatial distribution of sand, silt, clay and erodible fraction (EF) content were developed based onthose measurements. Our findings proved that soil texture change driven by wind erosion couldhappen relatively quickly, and a significant proportion of soil fine particles may be carried awaywithin a few years. The results indicate that the soil surface became much rougher over the period ofmore than 50 years, but also that the accumulation of fraction of the silt particles occurred in most ofthe areas affected by the erosive effect.Keywords:aeolian erosion; land degradation; GIS; sustainable agroecosystems; decision-makingprocesses; soil protection; wind erosion indicators; landscape entropy and stability1. IntroductionSoil erosion is a major cause of global-scale land degradation, and has increased by2.5% between 2001 and 2012. The main reasons for this increase are considered to be defor-estation and cropland expansion [1,2]. Soil erosion by wind is the process of destruction,separation, transportation and deposition of soil particles that affects negatively land andhuman health, agricultural production, as well as ecosystem services [3–5]. The process iscontrolled by several factors such as: wind speed and direction, temperature, precipitation,soil wetness, surface roughness, soil texture and aggregation, soil organic matter, vegetationcover, field size, agricultural activities and protective measures [6,7].

  • Looking Up to the Stars. A Call for Action to Save New Zealand’s Dark Skies for Future Generations to Come
    • Karolina Zielińska-Dąbkowska
    • Kyra Xavia
    2021 Pełny tekst Sustainability

    The rapid development of technology coupled with humanity’s desire to reach beyond terra firma, has resulted in more than 60 years of Outer Space activities. Although the exploration of space has provided many advantages and benefits to society so far, including vast, new information that has greatly added to our understanding of our planet and beyond, unfortunately, mankind’s footprint has negative aspects that need to be minimised as much as possible. In recent decades, a major worldwide problem has emerged in regard to the significant increase in light pollution from ground-based illuminations, as well as a lack of proper regulatory frameworks to mitigate the issue in order to protect the night sky and astronomical research. More recently, due to the escalating demand of air space for microsatellites and the rapid development of these new space technologies, as well as unmanned aerial vehicles (UAV), a new problem has arisen connected to visual light pollution (VLP). New Zealand has been especially affected, as, because of its dark skies, it has the third highest number of astronomical observatories in the world. The aim of this research is to identify critical areas for broader investigation; an action plan to improve the impact of new technologies is urgently required, not only at a national level but also worldwide. This is crucial in order to preserve humanity’s right to access the night sky and to also enable continual professional and amateur night-time observations for the present and the future, as well as for New Zealand to become a Dark Sky Nation.

  • Low-coherence photonic method of electrochemical processes monitoring
    • Monika Kosowska
    • Paweł Jakóbczyk
    • Michał Rycewicz
    • Alex Vitkin
    • Małgorzata Szczerska
    2021 Pełny tekst Scientific Reports

    We present an advanced multimodality characterization platform for simultaneous optical and electrochemical measurements of ferrocyanides. Specifcally, we combined a fber-optic Fabry– Perot interferometer with a three-electrode electrochemical setup to demonstrate a proof-ofprinciple of this hybrid characterization approach, and obtained feasibility data in its monitoring of electrochemical reactions in a boron-doped diamond flm deposited on a silica substrate. The flm plays the dual role of being the working electrode in the electrochemical reaction, as well as afording the refectivity to enable the optical interferometry measurements. Optical responses during the redox reactions of the electrochemical process are presented. This work proves that simultaneous opto-electrochemical measurements of liquids are possible.

  • Low-Cost Modeling of Microwave Components by Means of Two-Stage Inverse/Forward Surrogates and Domain Confinement
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    • Ullah Ubaid
    2021 Pełny tekst IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES

    Full-wave electromagnetic (EM) analysis is one of the most important tools in the design of modern microwave components and systems. EM simulation permits reliable evaluation of circuits at the presence of cross-coupling effects or substrate anisotropy, as well as for accounting for interactions with the immediate environment. However, repetitive analyses required by EM-driven procedures, such as parametric optimization or statistical analysis, may entail considerable computational expenditures, often prohibitive. Tackling the high-cost issue fostered the shift toward the incorporation of fast replacement models, including both physics-based surrogates and data-driven ones. While the latter is more popular and versatile, the construction of reliable approximation metamodels for microwave components is hindered by the curse of dimensionality and nonlinearity of system responses. The recent performance-driven modeling methodologies are capable of alleviating these difficulties by confining the surrogate domain to a vicinity of the optimum design manifold (i.e., the region that contains high-quality designs rather than the entire parameter space). Although setting up the model in a constrained domain requires small amounts of training data, domain definition itself requires a set of preoptimized reference designs, acquisition of which is an expensive endeavor. This work proposes a novel approach, which replaces the reference designs with a small set of random observables, thereby considerably reducing the overall cost of the model setup. Comprehensive verification involving several miniaturized microstrip structures demonstrates that our methodology is competitive to performance-driven frameworks both in terms of modeling accuracy and computational efficiency with an average savings of around 80%.

  • Low-cost multi-criterial design optimization of compact microwave passives using constrained surrogates and dimensionality reduction
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    • Muath Al-hasan
    2021 Pełny tekst INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS

    Design of contemporary microwave circuits is a challenging task. Typically, it has to take into account several performance requirements and constraints. The design objectives are often conflicting and their simultaneous improvement may not be possible; instead, compromise solutions are to be sought. Representative examples are miniaturized microwave passives where reduction of the circuit size has a detrimental effect on its electrical characteristics. Acquiring information about the best possible design trade‐offs is invaluable for the designer, yet it entails computationally expensive multi‐objective optimization (MO). MO is typically conducted using population‐based metaheuristic algorithms, the cost of which might be extremely high. If the circuit performance is evaluated using full‐wave electromagnetic (EM) analysis, this cost is often prohibitive. A workaround is the employment of fast surrogate models, and a number of surrogate‐assisted frameworks have been proposed in the literature. Unfortunately, a construction of reliable surrogates is hindered in higher dimensional parameter spaces. The recently proposed constrained modeling mitigates this issue to a certain extent by restricting the modeling process to the region containing the Pareto front to be found. This work proposes a novel surrogate‐based MO technique that involves constrained modeling and explicit reduction of the surrogate domain dimensionality. The latter is achieved through the spectral analysis of the extreme Pareto‐optimal design set obtained by local search routines. Our methodology is validated using a 15‐parameter impedance‐matching transformer with the Pareto set identified at the cost of a few hundred EM analyses of the circuit. The numerical experiments also demonstrate a significant reduction of the optimization cost as compared to the state‐of‐the‐art surrogate‐assisted MO methods.

  • Low-Cost Unattended Design of Miniaturized 4 × 4 Butler Matrices with Nonstandard Phase Differences
    • Adrian Bekasiewicz
    • Sławomir Kozieł
    2021 Pełny tekst SENSORS

    Design of Butler matrices dedicated to Internet of Things and 5th generation (5G) mobile systems—where small size and high performance are of primary concern—is a challenging task that often exceeds capabilities of conventional techniques. Lack of appropriate, unified design approaches is a serious bottleneck for the development of Butler structures for contemporary applications. In this work, a low-cost bottom-up procedure for rigorous and unattended design of miniaturized 4 × 4 Butler matrices is proposed. The presented approach exploits numerical algorithms (governed by a set of suitable objective functions) to control synthesis, implementation, optimization, and fine-tuning of the structure and its individual building blocks. The framework is demonstrated using two miniaturized matrices with nonstandard output-port phase differences. Numerical results indicate that the computational cost of the design process using the presented framework is over 80% lower compared to the conventional approach. The footprints of optimized matrices are only 696 and 767 mm2, respectively. Small size and operation frequency of around 2.6 GHz make the circuits of potential use for mobile devices dedicated to work within a sub-6 GHz 5G spectrum. Both structures have been benchmarked against the state-of-the-art designs from the literature in terms of performance and size. Measurements of the fabricated Butler matrix prototype are also provided.

  • Low-power microwave-induced fabrication of functionalised few-layer black phosphorus electrodes: A novel route towards Haemophilus Influenzae pathogen biosensing devices
    • Paweł Jakóbczyk
    • Marcin Kowalski
    • Mateusz Brodowski
    • Anna Dettlaff
    • Bartłomiej Dec
    • Dawid Nidzworski
    • Jacek Ryl
    • Tadeusz Ossowski
    • Robert Bogdanowicz
    2021 Pełny tekst APPLIED SURFACE SCIENCE

    In this paper, various passivation schemes were applied at few-layer black phosphorus (FLBP) to achieve covalent functionalisation with 4-azidobenzoic acid, improving its electrochemical response intended for analytical and biosensing applications. The thermal and microwave assisted modification procedures in toluene and dime-thylformamide resulted in high reversibility of reactions on functionalised FLBP using a ferricyanide/ferrocya-nide redox probe. The lowest peak-to-peak separation of 91 mV, and high kinetics were obtained by thermal synthesis in dimethylformamide. Attachment of a =N-phenylene-COOH moiety to the FLBP limits its degradation under ambient conditions delivering a linker for a peptide bond with proteins in the –NH2 groups. The functionalised FLBP was applied for impedimetric detection of the Haemophilus Influenzae (HI) bacterial protein with a low limit of detection (LOD) of 5.82 μg mL-1 along with high sensitivity equal to 1.267% μg-1 mL. The proposed strategy delivers a novel phosphorene-based electrode for sensitive detection of various bacterial pathogens.

  • Low-strain sensor based on the flexible boron-doped diamond-polymer structures
    • Michał Rycewicz
    • Mateusz Ficek
    • Krzysztof Gajewski
    • Srinivasu Kunuku
    • Jakub Karczewski
    • Teodor Gotszalk
    • I. Wlasny
    • Andrzej Wysmołek
    • Robert Bogdanowicz
    2021 Pełny tekst CARBON

    A free-standing high boron-doped diamond nanosheet (BDDNS) has been fabricated for the development of a flexible BDDNS strain senor. High boron-doped diamond was initially grown on a tantalum substrate in a microwave plasma-assisted chemical vapor deposition method, and was then transferred to a Kapton polymer substrate to fabricate the flexible BDDNS/Kapton device. Before performing the transfer process, the thin BDDNS’s morphology and bonding structure on the top and bottom surfaces were investigated using scanning electron microscopy and Raman spectroscopy. The contact potential difference and work function values of the BDDNS top and bottom surfaces were measured using a Kelvin probe atomic force microscope. Significant electrical conducting properties were observed from the resistance mapping of the BDDNS foil, and the average resistance value of 31 Ω attained from the top surface of the BDDNS foil. The electrical response of the BDDNS/Kapton device was investigated using a custom-made measurement system and a positive residual resistance change with strain was observed. The developed BDDNS/Kapton device was able to sustain for measuring up to 0.55% of strain, which indicates it may have great potential to be utilized in low-strain sensor applications.

  • Machine Learning and Electronic Noses for Medical Diagnostics
    • Wojciech Wojnowski
    • Kaja Kalinowska
    2021

    The need for noninvasive, easy-to-use, and inexpensive methods for point-of-care diagnostics of a variety of ailments motivates researchers to develop methods for analyzing complex biological samples, in particular human breath, that could aid in screening and early diagnosis. There are hopes that electronic noses, that is, devices based on arrays of semiselective or nonselective chemical sensors, can fill this niche. Electronic olfaction uses data processing and machine learning to build classification models based on the responses of several sensors in the form of multivariate datasets in order to discriminate between disease and healthy control based on a unique fingerprint. However, the introduction of this technique in clinical settings is limited by methodological issues which can, to some extent, be remedied using artificial intelligence. In this chapter, we provide a brief introduction to the electronic nose technique and outline its applications in medical diagnostics. We also discuss the ways in which data processing and machine learning techniques can be used to facilitate the use of electronic olfaction in the detection of disease.

  • MACHINE LEARNING APPLICATIONS IN RECOGNIZING HUMAN EMOTIONS BASED ON THE EEG
    • Adrian Kastrau
    • Michał Koronowski
    • Mariusz Liksza
    • Patryk Jasik
    2021

    This study examined the machine learning-based approach allowing the recognition of human emotional states with the use of EEG signals. After a short introduction to the fundamentals of electroencephalography and neural oscillations, the two-dimensional valence-arousal Russell’s model of emotion was described. Next, we present the assumptions of the performed EEG experiment. Detail aspects of the data sanitization including preprocessing, feature extraction, and target variable creation were also given. At the modeling stage, we created several classification models to establish a benchmark ranking of the problem related to the recognition of human emotions. Such a methodological approach enabled us to confirm that it is possible to build machine learning solutions allowing to recognize and classify human emotions with very high accuracy of over 90%.

  • Machine-Learning-Powered EM-Based Framework for Efficient and Reliable Design of Low Scattering Metasurfaces
    • Sławomir Kozieł
    • Muhammad Abdullah
    2021 Pełny tekst IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES

    Popularity of metasurfaces has been continuously growing due to their attractive properties including the ability to effectively manipulate electromagnetic (EM) waves. Metasurfaces comprise optimized geometries of unit cells arranged as a periodic lattice to obtain a desired EM response. One of their emerging application areas is the stealth technology, in particular, realization of radar cross section (RCS) reduction. Despite potential benefits, a practical obstacle hindering widespread metasurface utilization is the lack of systematic design procedures. Conventional approaches are largely intuition-inspired and demand heavy designer's interaction while exploring the parameter space and pursuing optimum unit cell geometries. Not surprisingly, these are unable to identify truly optimum solutions. In this article, we introduce a novel machine-learning-based framework for automated and computationally efficient design of metasurfaces realizing broadband RCS reduction. Our methodology is a three-stage procedure that involves global surrogate-assisted optimization of the unit cells, followed by their local refinement. The last stage is direct EM-driven maximization of the RCS reduction bandwidth, facilitated by appropriate formulation of the objective function involving regularization terms. The appealing feature of the proposed framework is that it optimizes the RCS reduction bandwidth directly at the level of the entire metasurface as opposed to merely optimizing unit cell geometries. Computational feasibility of the optimization process, especially its last stage, is ensured by high-quality initial designs rendered during the first two stages. To corroborate the utility of our procedure, it has been applied to several metasurface designs reported in the literature, leading to the RCS reduction bandwidth improvement by 15%-25% when compared with the original designs. Furthermore, it was used to design a novel metasurface featuring over 100% of relative bandwidth. Although the procedure has been used in the context of RCS design, it can be generalized to handle metasurface development for other application areas.

  • Magnetosonic Excitation of the Entropy Perturbations in a Plasma with Thermal Conduction Depending on Temperature
    • Anna Perelomova
    2021 Pełny tekst Archives of Acoustics

    Nonlinear excitation of the entropy perturbations by magnetosonic waves in a uniform and infinite plasma model is considered. The wave vector of slow or fast mode forms an arbitrary angle (0 B B ) with the equilibrium straight magnetic field, and all perturbations are functions of the time and longitudinal coordinate. Thermal conduction is the only factor which destroys isentropicity of wave perturbations and causes the nonlinear excitation of the entropy mode. A dynamic equation is derived which describes excitation of perturbation in the entropy mode in the field of dominant magnetosonic mode. Effects associatiated with temperature dependent and anisotropic thermal conduction are considered and discussed.

  • Management of Dark Fermentation Broth via Bio Refining and Photo Fermentation
    • Karolina Kucharska
    • Patrycja Makoś-Chełstowska
    • Edyta Słupek
    • Jacek Gębicki
    2021 Pełny tekst ENERGIES

    Lignocellulose and starch-based raw materials are often applied in the investigations regarding biohydrogen generation using dark fermentation. Management of the arising post-fermentation broth becomes a problem. The Authors proposed sequential processes, to improve the efficiency of both hydrogen generation and by-products management carried under model conditions. During the proposed procedure, the simple sugars remaining in broth are converted into organic acids, and when these products are used as substrates for the photo fermentation process. To enhance the broth management also conditions promoting Deep Eutectic Solvents (DES) precursors synthesis are simultaneously applied. Application of Box-Behnken design allows defining of the optimal conditions for conversion to DESs precursors. During the procedure hydrogen was obtained, the concentration of hydrogen in the photo fermentation reached up to 819 mL H2/L medium/7 d, depending on the broth type, i.e., when the broth was optimized for formic acid concentration. The DESs precursors were separated and engaged in DESs synthesis. To confirm the formation of the DESs, FT-IR analyses were performed. The Chemical Oxygen Demand of post-fermentation broths after dark fermentation optimized for formic acid was reduced by ca. 82%. The proposed procedure can be successfully used as a method of post-fermentation broth management.

  • Management of Urban Waters with Nature-Based Solutions in Circular Cities—Exemplified through Seven Urban Circularity Challenges
    • Hasan Volkan Oral
    • Matej Radinja
    • Anacleto Rizzo
    • Katharina Kearney
    • Theis Raaschou Andersen
    • Pawel Krzeminski
    • Gianluigi Buttiglieri
    • Derya Ayral-Cinar
    • Joaquim Comas
    • Magdalena Gajewska
    • Marco Hartl
    • David Christian Finger
    • Jan K. Kazak
    • Harri Mattila
    • Patrícia Vieira
    • Patrizia Piro
    • Stefania Anna Palermo
    • Michele Turco
    • Behrouz Pirouz
    • Alexandros Stefanakis
    • Martin Regelsberger
    • Nadia Ursino
    • Pedro Carvalho
    2021 Pełny tekst Water

    Nature-Based Solutions (NBS) have been proven to effectively mitigate and solve resource depletion and climate-related challenges in urban areas. The COST (Cooperation in Science and Technology) Action CA17133 entitled “Implementing nature-based solutions (NBS) for building a resourceful circular city” has established seven urban circularity challenges (UCC) that can be addressed effectively with NBS. This paper presents the outcomes of five elucidation workshops with more than 20 European experts from different backgrounds. These international workshops were used to examine the effectiveness of NBS to address UCC and foster NBS implementation towards circular urban water management. A major outcome was the identification of the two most relevant challenges for water resources in urban areas: ‘Restoring and maintaining the water cycle’ (UCC1) and ‘Water and waste treatment, recovery, and reuse’ (UCC2). s Moreover, significant synergies with ‘Nutrient recovery and reuse’, ‘Material recovery and reuse’, ‘Food and biomass production’, ‘Energy efficiency and recovery’, and ‘Building system recovery’ were identified. Additionally, the paper presents real-life case studies to demonstrate how different NBS and supporting units can contribute to the UCC. Finally, a case-based semi-quantitative assessment of the presented NBS was performed. Most notably, this paper identifies the most typically employed NBS that enable processes for UCC1 and UCC2. While current consensus is well established by experts in individual NBS, we presently highlight the potential to address UCC by combining different NBS and synergize enabling processes. This study presents a new paradigm and aims to enhance awareness on the ability of NBS to solve multiple urban circularity issues.

  • Managerial Energy in Sustainable Enterprises: Organizational Wisdom Approach
    • Monika Stelmaszczyk
    • Agata Pierścieniak
    • Anna Krzysztofek
    2021 Pełny tekst ENERGIES

    The circular economy (CE) as an idea involves applying the concept of sustainable development that has been gaining worldwide support. This shift in perception of energy and resource-use from its linear to circular forms creates a specific business environment, which constitutes the subject of this research. This article aims to analyze the impact of a manager’s energy on organizational wisdom, focusing on its circular business model activity. In the beginning, the article focuses on presenting ideas of the circular economy, emphasizing the manager’s activity in implementing strategic and operational tasks. These activities are identified as energy to launch mechanisms for developing organizational wisdom for sustainable enterprise. Assuming that organizational wisdom consists of two dimensions, organizational learning, and absorptive capacity, the research identifies relationships between them. The study was conducted at VIVE Textile Recycling Ltd., (Kielce, Poland). Empirical data were collected from 138 managers using the PAPI technique. Regression analysis and structural equation modeling (SEM) were applied to test the research hypotheses. Main results: Managerial energy (ME) is understood as the active attitude of managers who use knowledge from their environments to achieve goals both in the operational and strategic areas. Being an activating force for sustainable enterprise, ME is viewed as the antecedent to the development of enterprises operating in the CE model. ME directly activates the process of developing organizational wisdom in the area of absorptive capacity (AC) at the stages of assimilation, transformation, and exploitation. The transfer of knowledge from the individual to the organizational level (acquisition) requires a mediator, which is in this case the process of organizational learning (OL).

  • Managing change through team building in the context of organizing Erasmus+ mobility projects at the Gdańsk Tech Library
    • Urszula Szybowska
    • Magdalena Stankevic
    2021 Pełny tekst Zarządzanie Biblioteką

    The article discusses managing change through team building in the context of organizing Erasmus+ mobility projects in the Gdańsk University of Technology Library as the main strategy which contributed to the projects’ success. The authors describe the projects realized in the years 2017-2019 within the scope of the Erasmus+ programme. The organizers decided to take a responsible and active approach towards managing change and effective team building. Adopting and implementing the strategies according to the process of VMOSA (Vision, Mission, Objectives, Strategies, and Action Plans) turned out to be beneficial and made it possible to implement several successful mobility projects. The authors only mention that there might appear destructive factors which can seriously reduce a team’s effectiveness, highlighting the issue of a person or persons with a narcissistic personality disorder, which seems to be overlooked and underestimated in contemporary cross-disciplinary studies and management practice both in academic libraries and in other types of organizations.

  • MANDARIN PEEL AS AN AUSPICIOUS FUNCTIONAL FILLER FOR POLYMER COMPOSITES
    • Aleksander Hejna
    • Mateusz Barczewski
    • Paulina Kosmela
    • Joanna Aniśko
    • Olga Mysiukiewicz
    • Mariusz Marć
    2021 Pełny tekst Macedonian Journal of Chemistry and Chemical Engineering

    This work describes the application of mandarin peel (MP) as a waste filler for high-density polyethylene (HDPE) composites. The main goal was to investigate the impact of the filler's essential oils, which include multiple terpenes and terpenoids, on the processing, physicochemical, mechanical, and thermal properties of the composites as a function of different filler content (1 – 10 wt%), as well as its effect on the color and volatile organic compounds emissions of the composites. At small loadings, MP can be considered an efficient filler for wood-polymer composites, enhancing their flowability, tensile strength, and thermal stability. In addition, it may act as a colorant and aroma compound for polymer materials, and can enhance the thermooxidative resistance of composites. The oxidation induction time was increased from 20 min for HDPE up to 62 min for the composites with 10 wt% filler. The research results demonstrate the application of MP not only in the production of highly-filled composites, but also as an additive that significantly enhances the performance of composites at low concentrations.

  • Manganese–Cobalt Based Spinel Coatings Processed by Electrophoretic Deposition Method: The Influence of Sintering on Degradation Issues of Solid Oxide Cell Oxygen Electrodes at 750 °C
    • Elisa Zanchi
    • Justyna Ignaczak
    • Bartosz Kamecki
    • Piotr Jasiński
    • Sebastian Molin
    • A Boccaccini
    • Federico Smeacetto
    2021 Pełny tekst Materials

    This paper seeks to examine how the Mn–Co spinel interconnect coating microstructure can influence Cr contamination in an oxygen electrode of intermediate temperature solid oxide cells, at an operating temperature of 750 °C. A Mn–Co spinel coating is processed on Crofer 22 APU substrates by electrophoretic deposition, and subsequently sintered, following both the one-step and two-step sintering, in order to obtain significantly different densification levels. The electrochemical characterization is performed on anode-supported cells with an LSCF cathode. The cells were aged prior to the electrochemical characterization in contact with the spinel-coated Crofer 22 APU at 750 °C for 250 h. Current–voltage and impedance spectra of the cells were measured after the exposure with the interconnect. Post-mortem analysis of the interconnect and the cell was carried out, in order to assess the Cr retention capability of coatings with different microstructures.

  • Manufacturing and Recycling Impact on Environmental Life Cycle Assessment of Innovative Wind Power Plant Part 1/2
    • Krzysztof Doerffer
    • Patrycja Bałdowska-Witos
    • Michał Pysz
    • Piotr Doerffer
    • Andrzej Tomporowski
    2021 Pełny tekst Materials

    Wind power plants are considered as ecologically-clean source of energy. However, manufacturing processes cannot be treated that way. Manufacturing processes consume huge amount of electrical and thermal energy and significant amount of materials, e.g. steel, polymers, oils and lubricants. All of the above could be potentially harmful for environment. There are not many works and publications regarding life-cycle analysis of wind power plants. This study objective is to use LCA to the manufacturing and utilization of a specific drag force driven wind turbine. The discussed innovative wind turbine is of the type which assures safety for prosumer application. Drag force driven turbines become more heavy than other types of lift driven turbines but in the same time their characteristic provides opportunity to use easily recyclable materials instead of materials like plastics or composites. The wider look through LCA tools, may change the perspective of view at that type of wind turbines.. Analyzed turbine has capacity of 15 kW and is located in Poland. LCA was carried out using Eco-indicator 99 method in eleven impact categories. Among all of the turbine components the highest negative impact was noted in the case of the tower. Wind turbine under consideration is characterized by high recycling potential. According to presented research recycling provides around 30% reduction of environmental impact.

  • Manufacturing and Recycling Impact on Environmental Life Cycle Assessment of Innovative Wind Power Plant Part 2/2
    • Patrycja Bałdowska-Witos
    • Krzysztof Doerffer
    • Michał Pysz
    • Piotr Doerffer
    • Andrzej Tomporowski
    • Marek Opielak
    2021 Pełny tekst Materials

    The process of conversion of wind kinetic energy into electricity in innovative wind power plant emits practically no harmful substances into the environment. However, the production stage of its components requires a lot of energy and materials. The biggest problem during production plan-ning process of an innovative wind power plant is selection of materials and technologies and, consequently, the waste generated at this stage. Therefore, the aim of this publication was to conduct an environmental analysis of the life cycle of elements of a wind turbine by means of life cycle assessment (LCA) method. The object of the research was a wind power plant divided into five sets of components (tower, turbine structure, rotors, generators, and instrumentation), made mainly of steel and small amounts of polymer materials. Eco-indicator 99 was used as an analytical procedure. The impact of the subjects of analysis on human health, ecosystem quality and re-sources was assessed. Among the analyzed components, the highest level of negative impact on the environment was characterized by the life cycle of the wind turbine tower. The application of recycling processes is reducing the negative impact on the environment in the perspective of the entire life cycle of all studied elements of the wind power plant construction.

  • Mapping negative unintended consequences of disruptive technologies use in smart cities
    • Nina Rizun
    • Magdalena Ciesielska
    • Gabriela Viale Pereira
    • Charalampos Harris Alexopoulos
    2021

    Smart cities governance (SCG) consists of both to foster technology-enabled innovation, and to utilize disruptive technologies (DT) outcomes and impacts to increase public value of urban services. Despite widespread discussion of DT benefits, scientific literature identifies multiple determinants of unintended negative consequences (UC) of DT deployment in smart city initiatives. By considering UC as the negative aspects resulting from underestimating or ignoring the scale of such consequences, this study analyses the objectives of SCG and the negative unintended effects of five selected DT initiatives on these objectives’ implementation. The main contribution of this paper is the identification of determinants of negative UC of Smart City disruptive technologies initiatives and identifying the structure of their impact on the SCG objectives. The results indicate the need to establish a new governance framework of UC in smart cities as a tool to support local governments dealing with the changes caused by DT use in the smart city ecosystem

  • Mapping of the Covid-19 Vaccine Uptake Determinants From Mining Twitter Data
    • Anna Baj-Rogowska
    2021 Pełny tekst IEEE Access

    Opinion polls on vaccine uptake clearly show that Covid-19 vaccine hesitancy is increasing worldwide. Thus, reaching herd immunity not only depends on the efficacy of the vaccine itself, but also on overcoming this hesitancy of uptake in the population. In this study, we revealed the determinants regarding vaccination directly from people’s opinions on Twitter, based on the framework of the 6As taxonomy. Covid-19 vaccine acceptance depends mostly on the characteristics of new vaccines (i.e. their safety, side effects, effectiveness, etc.), and the national vaccination strategy (i.e. immunization schedules, quantities of vaccination points and their localization, etc.), which should focus on increasing citizens' awareness, among various other factors. The results of this study point to areas for potentially improving mass campaigns of Covid-19 immunization to increase vaccine uptake and its coverage and also provide insight into possible directions of future research.

  • Marian Żerebecki – saper, inżynier, wykładowca Politechniki Gdańskiej – mało znany, ale czy zapomniany?
    • Witold Parteka
    2021 Pismo PG

    Artykuł przedstawia sylwetkę Mariana Żerebeckiego – sapera, inżyniera, wykładowcy Politechniki Gdańskiej

  • Marine and Cosmic Inspirations for AI Algorithms
    • Marek Galewski
    • Piotr Duba
    2021 Pełny tekst Per mare ad astra

    Artificial Intelligence (AI) is a scientific area that currently sees an enormous growth. Various new algorithms and methods are developed and many of them meets practical, successful applications. Authors of new algorithms draw different inspirations. Probably the most common one is the nature. For example, Artificial Neural Networks were inspired by the structure of human brain and nervous system while the classic Genetic Algorithm was inspired by the biological evolution process. One of the important areas of AI algorithms applications are optimization problems which can be encountered in practically all fields of science, technology, and everyday life. Amongst AI algorithms used to solve optimization problems, especially large, and still broadening group are swarm intelligence algorithms. They are nature-inspired, meta-heuristic algorithms which usually solve optimization problems by mimicking biological or physical phenomena. They are based mainly on observations of behaviours of various species of animals for example birds , ants , grasshoppers , bees , bats , wolves , fish , dolphins and many other or implement physics laws or environmental phenomena like laws of gravity , motion of galaxies , lightning formation , hydrologic cycle , water evaporation , etc. The general advantages of swarm optimization are: simplicity, easy implementation and the lack of the objective function gradient information requirement. They are usually fast converging and can bypass local optima. Despite large number of algorithms there is no one, ultimate algorithm that solves all types of problems (single- and multi-objective, uni- and multi-modal, with and without boundaries, etc.). Thus, there is a permanent need for more algorithms with new, original inspirations. The paper presents general advantages of swarm intelligence algorithms and a short review of selected, interesting optimization algorithms that draw inspirations from marine nature and cosmic space. These are Gravitational Search Algorithm, Artificial Fish Swarm Optimization, Krill Herd, Whale Optimization Algorithm and Salp Swarm Algorithm

  • Marine Fuel Sulphur Limit Impact on Air Pollution
    • Dominik Kreft
    2021 International Journal of Ecology and Development

    The article presents calculation of Sulphur oxides percentage drop rate in marine industry recorded after 01.01.2020 when new limits, provided by International Maritime Organizations legislation, became effective. Ships’ SOx global emission was estimated and compared between 4th quarter 2019 and 1st quarter 2020. For more accurate estimation 3 seaside cities with big harbors were selected for statistical analysis. Noticeable SOx decrease was observed. In one case the drop was at similar level to theoretical. There were found significant correlations between heavy fuel oil bunker and SOx level in the air.

  • Massively parallel linear-scaling Hartree–Fock exchange and hybrid exchange–correlation functionals with plane wave basis set accuracy
    • Jacek Dziedzic
    • James C. Womack
    • Rozh Ali
    • Chris-Kriton Skylaris
    2021 Pełny tekst JOURNAL OF CHEMICAL PHYSICS

    We extend our linear-scaling approach for the calculation of Hartree–Fock exchange energy using localized in situ optimized orbitals [Dziedzic et al., J. Chem. Phys. 139, 214103 (2013)] to leverage massive parallelism. Our approach has been implemented in the ONETEP (Order-N Electronic Total Energy Package) density functional theory framework, which employs a basis of non-orthogonal generalized Wannier functions (NGWFs) to achieve linear scaling with system size while retaining controllable near-complete-basis-set accuracy. For the calculation of Hartree–Fock exchange, we use a resolution-of-identity approach, where an auxiliary basis set of truncated spherical waves is used to fit products of NGWFs. The fact that the electrostatic potential of spherical waves (SWs) is known analytically, combined with the use of a distance-based cutoff for exchange interactions, leads to a calculation cost that scales linearly with the system size. Our new implementation, which we describe in detail, combines distributed memory parallelism (using the message passing interface) with shared memory parallelism (OpenMP threads) to efficiently utilize numbers of central processing unit cores comparable to, or exceeding, the number of atoms in the system. We show how the use of multiple time-memory trade-offs substantially increases performance, enabling our approach to achieve superlinear strong parallel scaling in many cases and excellent, although sublinear, parallel scaling otherwise. We demonstrate that in scenarios with low available memory, which preclude or limit the use of time-memory trade-offs, the performance degradation of our algorithm is graceful. We show that, crucially, linear scaling with system size is maintained in all cases. We demonstrate the practicability of our approach by performing a set of fully converged production calculations with a hybrid functional on large imogolite nanotubes up to over 1400 atoms. We finish with a brief study of how the employed approximations (exchange cutoff and the quality of the SW basis) affect the calculation walltime and the accuracy of the obtained results.

  • Matematyka na zajęciach z arkuszy kalkulacyjnych
    • Agnieszka Bartłomiejczyk
    • Dawid Ptach
    • Marcin Wata
    2021 Pełny tekst Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

    Na zajęciach, zarówno w szkole, jak i na uczelni, do pokazania technicznej strony użycia arkusza kalkulacyjnego, tj.dostępnych funkcjonalności oraz organizacji danych, często wykorzystuje się proste zadania matematyczne. W naszym artykule zwracamy uwagę na potrzebę rozumienia przez użytkowników arkuszy kalkulacyjnych pojęć matematycznych, które umożliwiają odpowiednie przygotowanie danych oraz zinterpretowanie uzyskanych za pomocą narzędzi arkusza wyników. Zajęcia z Technologii informacyjnych, Arkuszy kalkulacyjnych czy z Zarządzania projektami są okazją do pokazania wagi interdyscyplinarności w nauce, w tym do motywowania, głębszego poznania i zrozumienia matematyki.

  • Materiały sorpcyjne wykorzystywane w maskach ochronnych
    • Paulina Nowicka
    • Marta Orciuch
    • Sandra Orylska
    • Sandra Rosa
    • Dominika Sołtyszewska
    • Natalia Łukasik
    2021 Pełny tekst Analityka: Nauka i Praktyka

    Od zarania dziejów ludzie starają się chronić przed chorobami zakaźnymi, stosując środki ochrony osobistej, do których należą maski ochronne. Z uwagi na obecnie panującą pandemię wirusa SARS-CoV-2, noszenie masek stało się normą w walce z koronawirusem. Jednak zagrożenia dla górnych dróg oddechowych nie stanowią wyłącznie wirusy, lecz również cząstki stałe zawieszone w powietrzu. Szczególnie w krajach wysoko uprzemysłowionych, narażenie na duże stężenie pyłów może przyczynić się nawet do śmierci, gdy dostaną się one do krwioobiegu. Z tego względu, noszenie masek może znacząco poprawić jakość zdrowia i życia. W tym artykule scharakteryzowano dostępne filtry w maskach ochronnych, do których należą membrany z nanowłókien polimerowych, filtry na bazie węgla aktywnego oraz filtry na bazie struktur metaloorganicznych (MOF). Przedstawiono także nowe rozwiązania, takie jak maski na bazie antybakteryjnych materiałów, które mają uskutecznić ochronę przed patogenami.

  • Mathematical approach to design 3D scaffolds for the 3D printable bone implant
    • Wiktoria Wojnicz
    • Marek Augustyniak
    • Piotr Borzyszkowski
    2021 Pełny tekst Biocybernetics and Biomedical Engineering

    This work demonstrates that an artificial scaffold structure can be designed to exhibit mechanical properties close to the ones of real bone tissue, thus highly reducing the stress-shielding phenomenon. In this study the scan of lumbar vertebra fragment was reproduced to create a numerical 3D model (this model was called the reference bone sample). New nine 3D scaffold samples were designed and their numerical models were created. Using the finite element analysis, a static compression test was performed to assess the effective Young modulus of each tested sample. Also, two important metrics of each sample were assessed: relative density and surface area. Each new designed 3D scaffold sample was analyzed by considering two types of material properties: metal alloy properties (Ti-6Al-4V) and ABS polymer properties. Numerical analysis results of this study confirm that 3D scaffold used to design a periodic structure, either based on interconnected beams (A, B, C, D, E and F units) or made by removing regular shapes from base solid cubes (G, H, I units), can be refined to obtain mechanical properties similar to the ones of trabecular bone tissue. Experimental validation was performed on seven scaffolds (A, B, C, D, E, F and H units) printed from ABS material without any support materials by using Fused Deposition Modeling (FMD) technology. Results of experimental Young modulus of each printed scaffold are also presented and discussed.

  • Mathematical model of the energy consumption calculation during the pine sawn wood (Pinus sylvestris L.) drying process
    • Aleksandra Konopka
    • Jacek Barański
    • Kazimierz Orłowski
    • Dariusz Mikielewicz
    • Ladislav Dzurenda
    2021 Pełny tekst WOOD SCIENCE AND TECHNOLOGY

    The article presents the modification of the existing mathematical model to calculate energy consumption during conventional drying process. Apart from energy consumption the model permits to estimate the time of high-temperature drying process. The drying medium is air and superheated steam mixture. The obtained calculation results were compared with conducted experimental tests of drying square-edged sawn sapwood timber (Pinus sylvestris L.). The pine sawn wood samples were dried according to three different drying modes, namely mild, normal and intense. The experiments were performed in a semi-industrial scale drying chamber. On the basis of the experimental research available, existing mathematical models of drying wood have been improved. The developed model included the following changes: a different drying time for each mode and type of drying medium (moisturized air or air and superheated steam mixture). The use of an intensive drying mode significantly reduced the drying process time. The developed mathematical model revealed that the energy consumption of the drying process increases with the intensity of the mode used.

  • Measured and predicted freeze-thaw days frequencies in climate change conditions in central Poland
    • Arkadiusz Bartczak
    • Halina Kaczmarek
    • Michał Badocha
    • Michał Krzemiński
    • Sebastian Tyszkowski
    2021 Pełny tekst PeerJ

    The rate of progression of geomorphological phenomena is greatly influenced by freeze-thaw processes. In the face of air temperature increasing over the past few decades, a question of the future impact of these processes arises, notably in the temperate and cold climate zones. Using the mean, maximum and minimum daily air temperature data in the period 1951–2018 obtained from three weather stations located in the vicinity of Jeziorsko reservoir (central Poland), we have determined the mathematical correlation, described with a polynomial function, between the mean monthly air temperature and the monthly number of freeze-thaw days (FTD). A freeze-thaw day is a day when the maximum air temperature is above 0 C while the minimum air temperature equals or is below this threshold. The number of FTDs within the study area averaged 64–71 and demonstrated a downward trend of 2–4 FTDs/10 years. The study period (1951–2018), includes a clearly marked distinct sub-period (1991–2018), when the reservoir was in operation, which experienced 58–68 FTDs. Considering the assumed rise in temperature, one should expect a further, though slightly slower, decline in the future number of FTDs. Depending on the accepted model of the temperature increase, which for the area of Poland (Central Europe) in the perspective of 30 years oscillates between +1.1 to +1.3 C, the number of FTDs within the study area is expected to decline by −4.5 to −5.3 FTD, i.e. 6–7% and 5.4–5.5 FTD i.e. 8–9% respectively.

  • Measurement Campaign and Mathematical Model Construction for the Ship Zodiak Magnetic Signature Reproduction
    • Jarosław Tarnawski
    • Krystian Buszman
    • Mirosław Wołoszyn
    • Tomasz Rutkowski
    • Adam Cichocki
    • R. Józwiak
    2021 Pełny tekst MEASUREMENT

    The paper presents the partial work done within the framework of the EDA Siramis II project focused on magnetic signature reproduction of ships. Reproduction is understood here as the ability to determine the magnetic anomaly of the local Earth magnetic field in any direction and at any measurement depth due to the presence of the analysed object. The B-91 type hydrographic ship Zodiak was selected as the real case study. The work was divided into two main stages: the development of a measurement campaign taking into account physical measurements, and the development of a mathematical model on the basis of the measured values. The measurement campaign included: preparation of the measuring range, selection of equipment for the measurement of magnetic quantities and geographical location, and data recording while the ship passes the measuring point according to the designated course. As a result of the measurement campaign, magnetic flux density components were collected in different positions in relation to the measuring instruments and the ship's heading. A multi-dipole model was used to build the mathematical model in accordance with the idea of inverse modelling. The effectiveness of this model was previously checked on synthetic data of virtual ships generated using the finite element method. Experiments performed with simulation models were helpful in determining the structure of the model, the nature of the data, and the number of samples needed to properly determine the multi-dipole model parameters. The parameters were determined using the nonlinear least squares method according to the idea of data fitting. The classical Ridge and Lasso regularization methods were applied to prevent the developed multi-dipole model from overfitting. Other regularization methods based on GPS accuracy marks and modification of fitness functions were also considered. The verification was done using real data: the data generated by the model was compared with patterns recorded during the Zodiak measurement campaign. High degree of conformity of the shape of characteristics was obtained. Moreover, the correctness of model execution was confirmed by low values of quantitative indices such as RMSE and MAE representing modelling errors. The methodology presented in the paper is quite universal and can be used to determine the signatures of other ferromagnetic objects.

  • Measurement of Seafloor Acoustic Backscatter Angular Dependence at 150 kHz Using a Multibeam Echosounder
    • Karolina Trzcińska
    • Jarosław Tęgowski
    • Paweł Poćwiardowski
    • Łukasz Janowski
    • Jakub Zdroik
    • Aleksandra Kruss
    • Maria Rucińska
    • Zbigniew Łubniewski
    • Jens Schneider von Deimling
    2021 Pełny tekst Remote Sensing

    Acoustic seafloor measurements with multibeam echosounders (MBESs) are currently often used for submarine habitat mapping, but the MBESs are usually not acoustically calibrated for backscattering strength (BBS) and cannot be used to infer absolute seafloor angular dependence. We present a study outlining the calibration and showing absolute backscattering strength values measured at a frequency of 150 kHz at around 10–20 m water depth. After recording bathymetry, the co-registered backscattering strength was corrected for true incidence and footprint reverberation area on a rough and tilted seafloor. Finally, absolute backscattering strength angular response curves (ARCs) for several seafloor types were constructed after applying sonar backscattering strength calibration and specific water column absorption for 150 kHz correction. Thus, we inferred specific 150 kHz angular backscattering responses that can discriminate among very fine sand, sandy gravel, and gravelly sand, as well as between bare boulders and boulders partially overgrown by red algae, which was validated by video ground-truthing. In addition, we provide backscatter mosaics using our algorithm (BBS-Coder) to correct the angle varying gain (AVG). The results of the work are compared and discussed with the published results of BBS measurements in the 100–400 kHz frequency range. The presented results are valuable in extending the very sparse angular response curves gathered so far and could contribute to a better understanding of the dependence of backscattering on the type of bottom habitat and improve their acoustic classification.

  • Measurement report: Spatial variations in ionic chemistry and water-stable isotopes in the snowpack on glaciers across Svalbard during the 2015–2016 snow accumulation season
    • Elena Barbaro
    • Krystyna Koziol
    • Mats P. Björkman
    • Carmen P. Vega
    • Christian Zdanowicz
    • Tonu Martma
    • Jean-Charles Gallet
    • Daniel Kępski
    • Catherine Larose
    • Bartłomiej Luks
    • Florian Tolle
    • Thomas Schuler
    • Aleksander Uszczyk
    • Andrea Spolaor
    2021 Pełny tekst ATMOSPHERIC CHEMISTRY AND PHYSICS

    The Svalbard archipelago, located at the Arctic sea-ice edge between 74 and 81∘ N, is ∼60 % covered by glaciers. The region experiences rapid variations in atmospheric flow during the snow season (from late September to May) and can be affected by air advected from both lower and higher latitudes, which likely impact the chemical composition of snowfall. While long-term changes in Svalbard snow chemistry have been documented in ice cores drilled from two high-elevation glaciers, the spatial variability of the snowpack composition across Svalbard is comparatively poorly understood. Here, we report the results of the most comprehensive seasonal snow chemistry survey to date, carried out in April 2016 across 22 sites on seven glaciers across the archipelago. At each glacier, three snowpits were sampled along the altitudinal profiles and the collected samples were analysed for major ions (Ca2+, K+, Na+, Mg2+, NH+4, SO2−4, Br−, Cl−, and NO−3) and stable water isotopes (δ18O, δ2H). The main aims were to investigate the natural and anthropogenic processes influencing the snowpack and to better understand the influence of atmospheric aerosol transport and deposition patterns on the snow chemical composition. The snow deposited in the southern region of Svalbard is characterized by the highest total ionic loads, mainly attributed to sea-salt particles. Both NO−3 and NH+4 in the seasonal snowpack reflect secondary aerosol formation and post-depositional changes, resulting in very different spatial deposition patterns: NO−3 has its highest loading in north-western Spitsbergen and NH+4 in the south-west. The Br− enrichment in snow is highest in north-eastern glacier sites closest to areas of extensive sea-ice coverage. Spatial correlation patterns between Na+ and δ18O suggest that the influence of long-range transport of aerosols on snow chemistry is proportionally greater above 600–700 m a.s.l.

  • Measurements of the Hydraulic Fluids Compressibility
    • Leszek Osiecki
    2021

    Performance of the hydrostatic high-pressure drive systems is affected by the changes of working fluid’s volume. Presence of air bubbles in the fluid cause this problem to be even more serious. To study this phenomenon precise measurements of fluid’s bulk modulus are necessary. Differ-ent measurement methods are applied, but they are either limited to low pressure range or give inaccurate results. To solve the problem the new measurement device was built. It allows to directly measure volume changes of both pure fluid or fluid-air mixture within the wide pressure and temperature range. Both adiabatic and isothermal module may be determined, the tested fluid may be pure or aerated.. Measurements of different fluids were made including vegetable oils (rapeseed, sunflower and linseed), mineral oil and synthetic oil.

  • Measurements of the optical and thermal properties of the 2D black phosphorus coating
    • Paulina Listewnik
    • Małgorzata Szczerska
    • Paweł Jakóbczyk
    2021 Pełny tekst Materials Research Express

    Black phosphorus is a 2D material, which properties are still being discovered. In this paper, the sensitivity to the temperature of a few-layer black phosphorus coating deposited, on the surface of a microsphere-based fiber-optic sensor, by a dip-coating method is presented. The coating was investigated after 2, 3, and 5 deposition cycles and during temperature growth from 50 °C to 300 °C in an interferometric setup. The intensity of the reflected signal increases with each applied layer. During the investigation of the thermal properties, in the range of 50 °C–200 °C, the polynomial growth rate of the reflected signal can be observed, whereas, for the temperatures over 200 °C, the measured peak intensity of the reflected signal stabilizes at a nearly constant level.

  • Measurements of Thermal Conductivity of LWC Cement Composites Using Simplified Laboratory Scale Method
    • Marzena Kurpińska
    • Jarosław Karwacki
    • Artur Maurin
    • Marek Kin
    2021 Pełny tekst Materials

    The implementation of low-energy construction includes aspects related to technological and material research regarding thermal insulation. New solutions are sought, firstly, to reduce heat losses and, secondly, to improve the environment conditions in isolated rooms. The effective heat resistance of insulating materials is inversely proportional to temperature and humidity. Cement composites filled with lightweight artificial aggregates may be a suitable material. Selecting a proper method for measuring the thermal conductivity of concrete is important to achieve accurate values for calculating the energy consumption of buildings. The steady state and transient methods are considered the two main thermal conductivity measurement approaches. Steady state is a constant heat transfer, whereby the temperature or heat flow is time independent. In the transient method, temperature changes over time. Most researchers have measured the conductivity of cement-based materials based on transient methods. The availability and cost of equipment, time for experimental measurements and measurement ability for moist specimens may be some of the reasons for using this method. However, considering the accuracy of the measurements, the steady state methods are more reliable, especially for testing dry materials. Four types of composites were investigated that differed in filler: natural aggregate, sintered fly ash filler, sintered clay and granular foam glass aggregate. The method of preparing the samples for testing is especially important for the obtained results. The samples, with a specific surface roughness, will show a lower coefficient of thermal conductivity by 20–30%; therefore, the selection of the type of contact layer between the plate of the measuring device and the sample is of particular importance.

  • Measures of Functional Reliability of Two-Lane Highways
    • Krzysztof Ostrowski
    • Marcin Budzyński
    2021 Pełny tekst ENERGIES

    Rural two-lane highways are the most common road type both in Poland and globally. In terms of kilometres, their length is by far greater than that of motorways and expressways. They are roads of one carriageway for each direction, which makes the overtaking of slower vehicles possible only when there is a gap in the stream of traffic moving from the opposite direction. Motorways and express roads are dual carriageways that are expected to support high speed travel mainly over long distances. Express roads have somewhat lower technical parameters and a lower speed limit than motorways. Two-lane highways are used for both short- and long-distance travel. The paper presents selected studies conducted in Poland in 2016–2018 on rural two-lane highways and focuses on the context of the need for their reliability. The research was carried out on selected short and [longer road sections located in various surroundings, grouped in terms of curvature change rate CCR, longitudinal slopes and cross-sections (width of lanes and shoulders). The studies of traffic volumes, travel time and travel speed, as well as traffic density, will be used to analyze traffic performance and identify measures of travel time reliability. The analyzed roads were characterized by good technical parameters and significant variability of traffic volume throughout the day, week and year. Some roads experience congestion, i.e., situations in which traffic volume Q is close to or above respective road capacity C. In order to determine the form of the suitable reliability measures, it will be important to determine the extent to which a road’s geometric and traffic characteristics impact travel speed and time. The paper presents well-known reliability measures for dual carriageways and proposes new measures, along with an evaluation of their usefulness in the assessment of the functioning of two-lane highways.