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  • Conductive Thermoplastic Polyurethane Nanocomposite Foams Derived from a Cellulose/MWCNTs Aerogel Framework: Simultaneous Enhancement of Piezoresistance, Strength, and Endurance
    • Yanpei Fei
    • Feng Chen
    • Wei Fang
    • Aleksander Hejna
    • Lixin Xu
    • Tong Liu
    • Zhong Mingqiang
    • Jintao Yang
    • Tairong Kuang
    2021 Journal of Materials Chemistry C

    High conductivity and excellent mechanical properties of composite polymers favors their application as piezoresistive strain sensors. Nonetheless, it is difficult to develop composite polymers with desirable piezoresistance, mechanicaland durable properties. Herein, we developed conductive cellulose/MWCNTs aerogel using the freeze-drying technique. Besides, we explored the application of the highly-sensitive piezoresistive polymer following supercritical carbon dioxide (ScCO2) foaming, in cellulose/MWCNTs aerogel-thermoplastic polyurethane (TPU) nanocomposites. Due to the low density (~0.15 g/cm3) of cellulose/MWCNTs, high porosity (90%) and high electric conductivity (2.04 S/m, cellulose/MWCNTs= 1/10), the CPC foam exhibited a remarkable low percolation threshold (MWCNTs loading of ~0.07%) and high piezoresistive sensitivity (GF value of 7.84). Nevertheless, the microcellular structure of composite foam remains stable with regard to energy loss coefficient and piezoresistance after several compression cycles (1000 cycles). The behavior of the prepared composite foams under different conditions was also evaluated. Overall, the piezoresistive sensors can be used in real-time monitoring of human movement.

  • Connected components of the space of proper gradient vector fields
    • Maciej Starostka
    2021 Pełny tekst Journal of Fixed Point Theory and Applications

    We show that there exist two proper gradient vector fields on Rn which are homotopic in the category of proper maps but not homotopic in the category of proper gradient maps.

  • Conservation aspects of cast-iron platform shelters on the example of Vistula Pomerania railway stations
    • Michał Kwasek
    2021 Pełny tekst Architectus

    Cast-iron shelters were used in the 19th century as cheaper alternatives to large platform halls. Nevertheless, they were aesthetically distinguishable from later riveted solutions. Because of their durability and continuous utility, they were not the subject of disassembly, as numerous transport infrastructure objects have been in recent decades. This article aims to indicate proper conservation practices during construction works on cast-iron platform shelters. Nowadays, most frequently, they take place during the modernization of railroad stations. As presented in this text, the approach to conservation procedures can be significantly different. The paper investigates technical and architectural solutions of selected instances of cast-iron platform shelters in Vistula Pomerania. Some references to foreign designs are also presented. The analysis of literature and archival documentation of the project, as well as the field studies, enabled us to formulate conclusions – recommendations for the proper procedure in respect of this type of object. Cast-iron platform shelters ought to be preserved as the unique remnant of 19th-century architecture. It is recommended to use an adequately selected material during the works and to restore the artistic qualities of cast-iron structures by restoring their original paintings. The author also refers to the realization of new roofing created in the preserved historical objects’ closest vicinity. Based on the illustrated instances, he recommends efforts to maintain consistency between new or reconstructed structures and authentic 19th-century ones. Simultaneously author emphasizes the necessity of avoiding the obliteration of the distinction between them. He drew attention to the challenges of repairing cast-iron pillars, giving examples of techniques that can be applied.

  • Consideration of dynamic loads in the determination of axle load spectra for pavement design
    • Dawid Ryś
    2021 Pełny tekst Road Materials and Pavement Design

    Axle load spectra constitute a crucial part of the data for pavement design and pavement distress analysis. Typically, axle load spectra represent static load from vehicles and do not include dynamic loads generated by vehicles in motion. While dynamic loads can significantly contribute to faster pavement distress, this fact is mostly omitted in pavement design methods. The paper presents a methodology for consideration of dynamic loads in axle load spectra for mechanistic-empirical pavement design. Calculations of dynamic axle load spectra for pavements of various evenness (expressed by IRI) and various vehicle speeds were performed and discussed. The effect of dynamic axle load spectra on pavement performance was analysed. M-EPDG calculations performed for three selected flexible pavements show that dynamic loads have a minor effect on pavement performance if the pavement is smooth and IRI is close to 1.0 mm/m. The detrimental effects of dynamic axle loads increase rapidly with the pavement evenness deterioration, resulting in faster (up to 25%) development of pavement distresses for IRI = 4.0 mm/m and a vehicle speed of 60 km/h. The analysis proved that thinner pavement structures are more sensitive to dynamic loads than thicker pavement structures. The investigation of vehicle speed impact on vehicle dynamic loads and pavement performance showed that at low vehicle speed (30 km/h) dynamic loads have a minor effect and pavement distress results mostly from a decrease in stiffness modulus of asphalt mixture and increase in permanent deformations, while for vehicle speeds higher than 90 km/h dynamic loads significantly contribute to pavement distress and adverse dynamic effects are not compensated by an increase in stiffness modulus of asphalt mixtures. The results also emphasise the significance of proper pavement evenness maintenance, especially on high speed motorways.

  • Contact with coupled adhesion and friction: Computational framework, applications, and new insights
    • Janine C. Mergel
    • Julien Scheibert
    • Roger Sauer
    2021 JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS

    Contact involving soft materials often combines dry adhesion, sliding friction, and large deformations. At the local level, these three aspects are rarely captured simultaneously, but included in the theoretical models by Mergel et al., (2019). We here develop a corresponding finite element framework that captures 3D finite-strain contact of two deformable bodies. This framework is suitable to investigate sliding friction even under tensile normal loads. First, we demonstrate the capabilities of our finite element model using both 2D and 3D test cases, which range from compliant tapes to structures with high stiffness, and include deformable–rigid and deformable–deformable contact. We then provide new results on the onset of sliding of smooth elastomer–glass interfaces, a setup that couples nonlinear material behavior, adhesion, and large frictional stresses. Our simulations not only agree well with both experimental and theoretical findings, they also provide new insights into the current debate on the shear-induced reduction of the contact area in elastomeric contact.

  • Contemporary bottom-up tools for public spaces activation. Współczesne oddolne narzędzia aktywizacji przestrzeni publicznych
    • Anastasiia Dubinina
    • Karolina Krośnicka
    • Magdalena Rembeza
    2021 Pełny tekst Przestrzeń Ekonomia Społeczeństwo

    This article attempts to figure out the current understanding of public spaces and the contemporary tools for bottom-up activation of public spaces to make them more friendly and functional. The paper investigates contemporary public spaces' challenges and what tools can be used to improve them. In this research, the main issue will be the question: what kind of tools and actions can be offered to maintain the quality of public spaces? There are two basic approaches for bettering public spaces: ‘bottom-up’ and ‘top-down’. The paper concentrates on the first approach and considers such methods as place-making and tactical urbanism in designing public spaces along with the community involvement. The work describes an increasing need for an architect, urban designer and planner to be involved in the process of city revitalisation as an interface between the local government and the inhabitants. This study attempts to answer the question of what is a connection between the architectural and social context of the public realm and the relationship between different types of public spaces, what makes public space friendly for users. How do public spaces help to strengthen social connections in towns, what is connection between architectural context and social context of the public realm. The presented study cases explain the different approaches and tools of place-making, including creative place-making.

  • Convenient Synthesis of Functionalized Unsymmetrical Vinyl Disulfides and Their Inverse Electron-Demand Hetero-Diels-Alder Reaction
    • Bartosz Jędrzejewski
    • Mateusz Musiejuk
    • Justyna Doroszuk
    • Dariusz Witt
    2021 Pełny tekst Materials

    The simple, convenient, and efficient methods for the preparation of unsymmetrical vinyl disulfides with additional functional groups under mild conditions with moderate to high yields were designed. The developed methods include the reaction of S-vinyl phosphorodithioate with thiotosylates or S-vinyl thiotosylate with thiols. The designed methods allow for the synthesis of unsymmetrical vinyl disulfides with additional functionalities such as hydroxy, carboxy, protected amino, or ester groups. Vinyl disulfides reacted with the generated transient o-iminothioquinones in an inverse electron-demand [4+2] cycloaddition to produce benzo[b][1,4]thiazine derivatives

  • Converting beach wrack into a resource as a challenge for the Baltic Sea (an overview)
    • Boris Chubarenko
    • Jana Woelfel
    • Jana Hofmann
    • Steffen Aldag
    • Jacek Bełdowski
    • Juris Burlakovs
    • T. Garrels
    • Julia Gorbunova
    • Sara Guizani
    • Alicja Kupczyk
    • Lech Kotwicki
    • D. Domnin
    • Magdalena Gajewska
    • William Hogland
    • Katarzyna Kołecka
    • Jacob Nielsen
    • Hendrik Schubert
    2021 OCEAN & COASTAL MANAGEMENT

    The paper distinguishes beach wrack, the marine generated organic part of beach cast, as a separate management object and discusses research questions related to its management and economically viable use. Based on experiences from the Baltic Sea and existing practices from countries with different management systems clear distinction between the management of natural and anthropogenic components of cast material is seen as an essential prerequisite for developing sustainable product chains that allow beach wrack to be used as a resource of commercial value. Presenting and discussing examples from Denmark, Germany, Poland, Russia and Sweden, social, ecological, and economic consequences of beach wrack removal are analysed to improve the attractiveness of beaches for recreational purposes. It also includes potential contribution to Baltic Sea water restoration processes through the removal of the organic part of beach cast, where indeed more studies about the chemical (nutrients, metals) composition of beach wrack are required for reliable calculation of a depuration rate. For local economies within the Baltic Sea region, the organic part of beach cast (beach wrack and terrestrial debris) has reasonable economic prospects as a renewable natural resource, e.g. for soil improvement products, in fertilisers and bio-coal production, for landfill covers (contributing to climate change mitigation), biogas generation, and even for coastal protection by providing humus-like material for accelerated dune vegetation succession. For all these recycling options the development of cost-efficient technologies for collecting beach cast on sandy as well as stony beaches and also for separating the organic part from sand and anthropogenic litter (mainly plastic), is urgently required. Amendments of legal regulations, that better reflect the dualism of beach cast are also required. In essence, dualism results from the fact that beach wrack is a part of nature (or a natural resource) when it remains on a beach. However, beach wrack immediately becomes legally categorised as waste once humans collect it irrespective of its litter content. Another legal aspect being dealt with originates from the migration of the beach wrack between water and beach, whilst it is an object of ерleagl cleaning operations only at the beach it onto the beach, but not whilst in the water.

  • Copper and copper-manganese 1D coordination polymers: Synthesis optimization, crystal structure and preliminary studies as catalysts for Baylis–Hillman reactions
    • Julyanna Cândido Dutra de Andrade
    • Lucas Araujo Trajano Silva
    • Claudio Gabriel Lima-Junior
    • Jarosław Chojnacki
    • Mário Luiz Araújo de Almeida Vasconcellos
    • R.b. da Silva
    • Severino Alves Junior
    • Fausthon F. da Silva
    2021 INORGANICA CHIMICA ACTA

    This work reports the influence of experimental parameters (pH and counter-ion) in the synthesis of the 1D coordination polymer [Cu(IDA)(H2O)2]n (IDA = iminodiacetate), named here Cu-IDA. Copper-manganese bimetallic coordination polymers were also obtained by isomorphic replacement into Cu-IDA structure, with different molar ratio of Cu2+ and Mn2+ ions, denoted here as Cu/Mn-IDA (0.9/0.1; 0.7/0.3 and 0.5/0.5). New coordination polymers are isostructural to Cu-IDA and amounts of manganese atoms inserted into crystalline structure were evaluated by single-crystal X-ray diffraction and Rietveld refinement. All coordination polymers obtained were also characterized by infrared absorption spectroscopy and thermogravimetric analysis. Homometallic and bimetallic compounds were evaluated as catalysts for Baylis-Hillman reaction with yields and reaction times comparable or superior to those in the literature. Compounds containing manganese cations shows higher catalytic performance, especially Cu/Mn-IDA (0.9/0.1) with yield 91% in 5 h of reaction. Results also indicate an important role played by the metallic centre in the catalytic mechanism

  • Copper Slag as a Potential Waste Filler for Polyethylene-Based Composites Manufacturing
    • Aleksander Hejna
    • Paulina Kosmela
    • Mateusz Barczewski
    • Olga Mysiukiewicz
    • Adam Piasecki
    2021 Pełny tekst Tanzania Journal of Science

    The present study aimed to analyze the application of waste material from copper production– copper slag (ŻŻL) as filler for composites based on the high-density polyethylene (HDPE). Copper slag filler was introduced in the amounts of 1–20 wt%, and its influence on the appearance (color analysis), chemical structure (Fourier-transform infrared (FTIR) spectroscopy), microstructure (optical microscopy), as well as static (tensile tests) and dynamic (dynamical mechanical analysis (DMA)) mechanical properties of composites were investigated. Proper dispersion of filler implicated that the incorporation of up to 5 wt% of filler caused only slight, 5% drop of tensile strength, with the simultaneous 16% rise of Young’s modulus. Further increase of filler loading resulted in higher values of porosity and the rise of the adhesion factor, determined from DMA results, which led to the deterioration of mechanical performance. Moreover, spectroscopic analysis of PE-ŻŻL composites indicated that the analyzed filler might be applied as a coloring agent, and the appearance of composites may be engineered by adjustment of filler loading.

  • Copper(I) halide cluster-based coordination polymers modulated by chiral ditopic dithiodianthranilide ligands: synthesis, crystal structure and photoluminescence
    • Jarosław Chojnacki
    • Teresa Olszewska
    • Tadeusz Połoński
    • Michał Mońka
    • Illia E. Serdiuk Serdiuk
    • Piotr Bojarski
    2021 CRYSTENGCOMM

    Reaction of copper(I) halides with chiral dithiodianthranilidesmdtaandbdtaafforded polymeric complexeswhere polynuclear CuX clusters were linked together by ditopic bridging ligands into 1D chains or 2D layerstructures. In the case of racemic ligands double stranded chain polymers were formed where the Cu4X4(X = I or Br) cores are connected by enantiomeric pairs of the ditopic ligands. In contrast, a homochiralmdtaligand created a single stranded hybrid chain involving singlemdtaenantiomers and solvated Cu5I5clusters or 2D square (4,4) nets composed of rings comprising four Cu3X3clusters in nodes and fourhomochiral ligand molecules in sides with solvent MeCN molecules between the grid layers. The hybridlayer structure obtained from CuCl and the racemicmdtaligand crystallized as a conglomerate that led toits self-resolution into enantiomeric chiral crystals. The solid state CD spectra revealed contribution of twoelectronic transitions to the diffuse lowest energy absorption band of the complexes. In addition theobserved long wavelength Cotton effect sign reflected the helicity of the thiobenzamide chromophore inthe ligand unit. At room temperature the solid complexes exhibited weak red phosphorescence near 600–620 nm. Upon cooling down to 10 K all investigated complexes are phosphorescent with average lifetimesof 17–84μs.

  • Correlation between Fractal Dimension and Areal Surface Parameters for Fracture Analysis after Bending-Torsion Fatigue
    • Wojciech Macek
    2021 Pełny tekst Metals

    This paper investigates the fracture surface topography of two steel and aluminum alloys subject to bending-torsion fatigue loadings, as well as their susceptibility to fatigue performance and failure mechanisms. Using fracture surface topography data analysis, elements with different geometries were elaborated. A correlation between the fractal dimension, other selected parameters of surface topography such as areal Sx, and fatigue loading conditions was found. Distinctions in particular regions of cracks were also recognized through proving the correctness and universality of the total fracture surface method. The influence of fatigue loading parameters on the surface to pography of fatigue fractures was demonstrated. For the analyzed cases, results show that the frac tal dimension and standard surface topography parameters represent a correlation between them and loading conditions. As a single parameter, the appropriate loading ratio cannot be outright calculated with fractal dimension, but can be estimated with some approximation, taking into ac count additional assumptions.

  • Corrosion Resistance and Surface Bioactivity of Ti6Al4V Alloy after Finish Turning under Ecological Cutting Conditions
    • Kamil Leksycki
    • Agnieszka Kaczmarek-Pawelska
    • Kamil Ochał
    • Andrzej Gradzik
    • Danil Yurievich Pimenov
    • Khaled Giasin
    • Daniel Chuchała
    • Szymon Wojciechowski
    2021 Pełny tekst Materials

    The influence of cooling conditions and surface topography after finish turning of Ti6Al4V titanium alloy on corrosion resistance and surface bioactivity was analyzed. The samples were machined under dry and minimum quantity lubrication (MQL) conditions to obtain different surface roughness. The surface topographies of the processed samples were assessed and measured using an optical profilometer. The produced samples were subjected to electrochemical impedance spectroscopy (EIS) and corrosion potential tests (Ecorr) in the presence of simulated body fluid (SBF). The surface bioactivity of the samples was assessed on the basis of images from scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) analysis. The inspection of the surfaces of samples after turning under dry and MQL conditions revealed unevenly distributed precipitation of hydroxyapatite compounds (Ca/P) with a molar ratio in the range of 1.73–1.97. Regardless of the cutting conditions and surface roughness, the highest values of Ecorr ~0 mV were recorded on day 7 of immersion in the SBF solution. The impedance characteristics showed that, compared to the MQL conditions, surfaces machined under dry conditions were characterized by greater resistance and the presence of a passive layer on the processed surface. The main novelty of the paper is the study of the effect of ecological machining conditions, namely, dry and MQL cutting on the corrosion resistance and surface bioactivity of Ti6Al4V titanium alloy after finish turning. The obtained research results have practical significance. They can be used by engineers during the development of technological processes for medical devices made of Ti6Al4V alloy to obtain favorable functional properties of these devices.

  • Cost-Efficient EM-Driven Size Reduction of Antenna Structures by Multi-Fidelity Simulation Models
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    2021 Pełny tekst Electronics

    Design of antenna systems for emerging application areas such as the Internet of Things (IoT), fifth generation wireless communications (5G), or remote sensing, is a challenging endeavor. In addition to meeting stringent performance specifications concerning electrical and field properties, the structure has to maintain small physical dimensions. The latter normally requires searching for trade-off solutions because miniaturization has detrimental effects on antenna characteristics, in-cluding the impedance matching, gain, efficiency, or axial ratio bandwidth. Furthermore, explicit size reduction is more demanding than optimization with respect to other figures of merit. On the one hand, it is a constrained task with acceptance thresholds set on the bandwidth, gain, etc. On the other hand, optimum solutions are normally located at the boundary of the feasible region, traversing of which is a difficult problem by itself. The necessity of using full-wave electromagnet-ic (EM) analysis for antenna evaluation only aggravates the problem due to high computational costs associated with numerical optimization algorithms. This paper proposes a procedure for ex-pedited optimization-based miniaturization of antenna structures involving trust-region gradient search and multi-fidelity EM simulations, as well as implicit handling of design constraints using a penalty function approach. The assumed model management scheme is associated with the con-vergence status of the optimization process with the lowest fidelity model employed at the early stages of the algorithm run and the discretization density of the structure gradually increased to reach the high-fidelity level towards the end of the run. This allows us to achieve a considerable computational speedup without compromising the reliability. Our methodology is demonstrated using two broadband microstrip antennas. The obtained CPU savings exceed seventy percent as compared to the reference procedure involving high-fidelity model only.

  • Coupling between Blood Pressure and Subarachnoid Space Width Oscillations during Slow Breathing
    • Agnieszka Gruszecka
    • Magdalena Nuckowska
    • Monika Waskow
    • Jacek Kot
    • Pawel Winklewski
    • Wojciech Guminski
    • Andrzej F. Frydrychowski
    • Jerzy Wtorek
    • Adam Bujnowski
    • Piotr Lass
    • Tomislav Stankovski
    • Marcin Gruszecki
    2021 Pełny tekst ENTROPY

    The precise mechanisms connecting the cardiovascular system and the cerebrospinal fluid (CSF) are not well understood in detail. This paper investigates the couplings between the cardiac and respiratory components, as extracted from blood pressure (BP) signals and oscillations of the subarachnoid space width (SAS), collected during slow ventilation and ventilation against inspiration resistance. The experiment was performed on a group of 20 healthy volunteers (12 females and 8 males; BMI =22.1±3.2 kg/m2; age 25.3±7.9 years). We analysed the recorded signals with a wavelet transform. For the first time, a method based on dynamical Bayesian inference was used to detect the effective phase connectivity and the underlying coupling functions between the SAS and BP signals. There are several new findings. Slow breathing with or without resistance increases the strength of the coupling between the respiratory and cardiac components of both measured signals. We also observed increases in the strength of the coupling between the respiratory component of the BP and the cardiac component of the SAS and vice versa. Slow breathing synchronises the SAS oscillations, between the brain hemispheres. It also diminishes the similarity of the coupling between all analysed pairs of oscillators, while inspiratory resistance partially reverses this phenomenon. BP–SAS and SAS–BP interactions may reflect changes in the overall biomechanical characteristics of the brain.

  • Coupling transformation of carbon, nitrogen and sulfur in a long-term operated full-scale constructed wetland
    • Jacek Mąkinia
    • Wenbo Liu
    • Md. Hasibur Rahaman
    • Jun Zhai
    2021 Pełny tekst SCIENCE OF THE TOTAL ENVIRONMENT

    The coupling transformation of carbon, nitrogen and sulfur compounds has been studied in lab-scale and pilot-scale constructed wetlands (CWs), but few studies investigated full-scale CW. In this study, we used batch experiments to investigate the potentials of carbon, nitrogen and sulfur transformation in a long-term operated, full-scale horizontal subsurface flow wetland. The sediments collected from the HSFW were incubated for 48h in the laboratory with supplying various dosages of carbon, nitrogen and sulfur compounds. The results showed that heterotrophic denitrification was the main pathway. At the same time, the sulfide(S2-)-based autotrophic denitrification was also present. Increasing TOC concentration or NO3- concentration could promote heterotrophic denitrification but did not inhibit the sulfide-based autotrophic denitrification. In our experiment, the highest NO3- removal via autotrophic denitrification was 25.23% while that via heterotrophic denitrification was 73.66%, leading to the total NO3- removal of 98.89%. The results also demonstrated that NO3- rather than NO2- was the preferable electron acceptor for both heterotrophic and sulfide-based autotrophic denitrification in the CW. Increasing S2- concentrations promote NO3- removal from 12.99% to 25.23% without organic carbon, but varying NO3- or NO2- has no effects. These results indicated that concentrations of S2-, instead of NO3- or NO2-, was the limiting factor for sulfide-based autotrophic denitrification in the studied CW. The microbial community analysis and correlation analysis between the transformation of carbon, nitrogen and sulfur compounds and relative abundance of bacteria further confirmed that in the CW, the key pathways coupling transformation were heterotrophic denitrification and sulfide-based autotrophic denitrification. Overall, the current study will enhance understanding of carbon, nitrogen, and sulfur transformation in CW and support better design and treatment efficiency.

  • Creating Polish space language dictionary - lessons learned
    • Adam Dąbrowski
    • Marek Moszyński
    2021 Pełny tekst

    Polish space industry suffers from lack of space vocabulary. Since joining European Space Agency in 2012, the sector has expanded rapidly now employing over 1000 specialists focusing mainly on space sustainability, space debris detection and tracking, robotics and propulsion systems. The Polish Space Agency together with The Polish Committee for Standardization have committed to creating the first lexicon of space language, along with definitions and even standards. Such tool will be used both in daily work of the industry as well as in teaching students and young professionals. This paper presents a unique challenge of creating a space wordbook from scratch with proper care for a language maintaining habits already established in the country. The task of the Polish Space Agency is to support the Polish space industry by combining the world of business and science. An important aspect of the Agency's activity is to promote the development of satellite technology that can be used in everyday life, including communication, navigation, environmental monitoring and weather forecasting. The Polish Committee for Standardization (Polski Komitet Normalizacyjny – PKN) is a national standards body responsible for the organization of standardization activities. The PKN is not a government agency, but a body governed by public law.

  • Creating Shared Value by the University
    • Elżbieta Karwowska
    2021 Social Responsibility Journal

    Purpose Works that link creating shared value (CSV) with the university are arising, and there is a hope for a great future of this combination. The main problem with these works is that they are based on the wrong assumptions of what CSV is. The aim of the paper is to properly explain the concept of CSV and match it with university social responsibility (USR) at a strategic level. Design/methodology/approach A literature review on CSV and USR is briefly outlined. Then, at the foundation of existing models of the USR, normative model that integrates CSV at a strategic level is proposed. To validate the model and explain its assumptions, a qualitative study on Polish universities was conducted. Furthermore, a piece of recommendation for implementing CSV is presented. Findings Signs of CSV at universities have been observed. The trend may have positive implications, as it is similar to the recommended strategy: starting small, doing good and growing the program based on the lessons learned. Research limitations/implications In this study, the ecosystem’s impact on CSV at the university has been omitted. The qualitative research was based on vaguely distinguished aspects proposed by the new model. One should be cautious about considering findings as anything more than observations. Practical implications The normative model may serve as a foundation for future research or a practical guideline to higher education institutions. Originality/value The paper links CSV with USR at a strategic level supported by real examples of activities that create social and economic value. The normative model may serve as a foundation for future research or a practical guideline to higher education institutions.

  • CRUNCH Time na 17 Biennale Architektury w Wenecji, w Pawilonie Włoskim
    • Joanna Bach-Głowińska
    2021

    https://arch.pg.edu.pl/strona-glowna/wydarzenia/crunch-time-na-biennale-architektury-w-wenecji-2021 https://pg.edu.pl/aktualnosci/2021-10/sukces-gdanskich-urbanistow-crunch-time-na-biennale-architektury-w-wenecji

  • Crystalline Polysaccharides: A Review
    • Farzad Seidi
    • Mohsen Khodadadi Yazdi
    • Maryam Jouyandeh
    • Sajjad Habibzadeh
    • Muhammad Tajammal Munir
    • Henri Vahabi
    • Babak Bagheri
    • Navid Rabiee
    • Payam Zarrintaj
    • Mohammad Saeb
    2021 CARBOHYDRATE POLYMERS

    The biodegradability and mechanical properties of polysaccharides are dependent on their architecture (linear or branched) as well as their crystallinity (size of crystals and crystallinity percent). The amount of crystalline zones in the polysaccharide significantly governs their ultimate properties and applications (from packaging to biomedicine). Although synthesis, characterization, and properties of polysaccharides have been the subject of several review papers, the effects of crystallization kinetics and crystalline domains on the properties and application have not been comprehensively addressed. This review places focus on different aspects of crystallization of polysaccharides as well as applications of crystalline polysaccharides. Crystallization of cellulose, chitin, chitosan, and starch, as the main members of this family, were discussed. Then, application of the aforementioned crystalline polysaccharides and nano-polysaccharides as well as their physical and chemical interactions were overviewed. This review attempts to provide a complete picture of crystallization-property relationship in polysaccharides.

  • Current divider-based nanosecond high current pulse measuring systems
    • Mikołaj Nowak
    • Kazimierz Jakubiuk
    • Daniel Kowalak
    • Marek Pikoń
    • Józef Czucha
    • Jacek Starzyński
    2021 Pełny tekst MEASUREMENT

    This paper presents the analysis of the new approach to the measurement methodology of significant values (in order of hundreds of kA) and huge steepness (in order of MA/μs) current pulses based on current dividers along with a comparison of the various types transducers suitability in measuring systems with such extreme parameters. Such dividers are used to extend the measurement ranges of current transducers with limited current conversion capabilities. The results of the selected current dividers field-circuit simulations have been presented, including their attributes and potential application as an important elements of the high-current measurement circuits. The physical prototypes of dividing systems have been verified using an experimental high-power pulse generation and forming system based on the flux compression generator and ultra-fast fuse-opening switch. As the additional aim of this study, the dividers current ratio error compensation method based on the general field-circuit model of current divider has been proposed.

  • Current Source Inverter Fed Drive
    • Marcin Morawiec
    • Arkadiusz Lewicki
    2021

    This book covers three-phase and multiphase (more than three-phase) motor drives including their control and practical problems faced in the field (e.g., adding LC filters in the output of a feeding converter), are considered. The new edition contains links to Matlab®/Simulink models and PowerPoint slides ideal for teaching and understanding the material contained within the book. Readers will also benefit from the inclusion of: A thorough introduction to high performance drives, including the challenges and requirements for electric drives and medium voltage industrial applications An exploration of mathematical and simulation models of AC machines, including DC motors and squirrel cage induction motors A treatment of pulse width modulation of power electronic DC-AC converter, including the classification of PWM schemes for voltage source and current source inverters Examinations of harmonic injection PWM and field-oriented control of AC machines Voltage source and current source inverter-fed drives and their control Modelling and control of multiphase motor drive system Supported with a companion website hosting online resources.

  • Curved Surface Minijet Impingement Phenomena Analysed with ζ-f Turbulence Model
    • Tomasz Kura
    • Elżbieta Fornalik-Wajs
    • Jan Wajs
    • Sasa Kenjeres
    2021 Pełny tekst ENERGIES

    The jet impingement phenomenon plays an important role among the heat transfer intensification methods. Very often its application and analyses refer to simple flat surfaces, while there is a lack of information in the literature for cases addressing curved surfaces. In the present work, the single jet impingement on the non-flat (concave and convex) surface is studied for a wide range of geometries, which originate from the mini-jet heat-exchanger design. The numerical simulations were performed by an advanced ζ-f turbulence model implemented in the open-source OpenFOAM (ESI-OpenCFD Ltd, Bracknell, United Kingdom) code. Noticeable differences in the phenomena occurring on the convex and concave surfaces were identified in the stagnation zone. Besides, the existence and location of the secondary peak in the Nusselt number distribution differed between the cases. These distributions were influenced by the shape of geometry, which determined flow characteristics and resulting heat transfer performance. The origins of these differences were looked at in the turbulence characteristics close to the impinged surface of the stagnations zone and its vicinity, where turbulence kinetic energy and enstrophy were analysed. It was stated that the differences are already noticeable for the single jet impingement case, but they might sum up when multiple jets are considered. Therefore, here presented results would be important for the analysis of the overall unit of mentioned mini-jets heat-exchanger.

  • CyberEye: New Eye-Tracking Interfaces for Assessment and Modulation of Cognitive Functions beyond the Brain
    • Michał Lech
    • Andrzej Czyżewski
    • Michał Kucewicz
    2021 Pełny tekst SENSORS

    The emergence of innovative neurotechnologies in global brain projects has accelerated research and clinical applications of BCIs beyond sensory and motor functions. Both invasive and noninvasive sensors are developed to interface with cognitive functions engaged in thinking, communication, or remembering. The detection of eye movements by a camera offers a particularly attractive external sensor for computer interfaces to monitor, assess, and control these higher brain functions without acquiring signals from the brain. Features of gaze position and pupil dilation can be effectively used to track our attention in healthy mental processes, to enable interaction in disorders of consciousness, or to even predict memory performance in various brain diseases. In this perspective article, we propose the term ‘CyberEye’ to encompass emerging cognitive applications of eye-tracking interfaces for neuroscience research, clinical practice, and the biomedical industry. As CyberEye technologies continue to develop, we expect BCIs to become less dependent on brain activities, to be less invasive, and to thus be more applicable.

  • Cytocompatibility of stabilized black phosphorus nanosheets tailored by directly conjugated polymeric micelles for human breast cancer therapy
    • M. Biedulska
    • Paweł Jakóbczyk
    • Marta Sosnowska
    • Bartłomiej Dec
    • A. Muchlińska
    • A. J. Zaczek
    • Dawid Nidzworski
    • Robert Bogdanowicz
    2021 Pełny tekst Scientific Reports

    The novel procedure of few-layer black phosphorus (FLBP) stabilization and functionalisation was here proposed. The cationic polymer PLL and non-ionic PEG have been involved into encapsulation of FLBP to allow sufficient time for further nanofabrication process and overcome environmental degradation. Two different spacer chemistry was designed to bind polymers to tumor-homing peptides. The efficiency of functionalisation was examined by RP-HPLC, microscopic (TEM and SEM) and spectroscopic (FT-IR and Raman) techniques as well supported by ab-initio modelling. The cell and dose dependent cytotoxicity of FLBP and its bioconjugates was evaluated against HB2, MCF-7 and MDA-MB-231 cell lines. Functionalisation allowed not only for improvement of environmental stability, but also enhances therapeutic effect by abolished the cytotoxicity of FLBP against HB2 cell line. Moreover, modification of FLBP with PLL caused increase of selectivity against highly aggressive breast cancer cell lines. Results indicate the future prospect application of black phosphorus nanosheets as nanocarrier, considering its unique features synergistically with conjugated polymeric micelles.

  • Czy Ziemia przetrwa inwazję człowieka?
    • Zygfryd Witkiewicz
    • Waldemar Wardencki
    • Anna Świercz
    2021

    Zagadnienia poruszane w książce maja charakter uniwersalny, zwracaja uwagę na zagrożenia egzystencjalne dla naszej planety. Zagrazenia te zwiazane są w dużej mierze z działalnościa czlowieka, których skutki sa przede wszystkim niepokojace zmiany klimatu i utrata bioróżnorodności. Sytuację pogarsza ciagle wzrastajaca liczba ludności, która nie chce ograniczać produkcji dóbr konsumpcyjnych, a jednocześnie wprowadza do srodowiska coraz więcej zanieczyszczeń, głównie chemicznych. Coraz wiekszym problemem staja się także zanieczyszczenia tworzywami sztucznymi i odpady komunalno-przemysłowe.

  • Damage detection in plates based on Lamb wavefront shape reconstruction
    • Beata Zima
    2021 Pełny tekst MEASUREMENT

    Many of the current studies in the area of damage detection using elastic wave propagation are based on deploying sensor networks with a large number of piezoelectric transducers to detect small-size cracks. A major limitation of these studies is that cracks are usually larger and have different shapes in real cases. Moreover, using a large number of sensing nodes for damage detection is both costly and computationally intensive. The paper proposes a novel elastic wave propagation method for damage detection based on the reconstruction of the shape of the reflected wavefront. The main advantage of the developed approach is that merely three sensors are necessary to localize and estimate the size of the cracks with various sizes and shapes. Several damage cases with different number of piezoelectric transducers and placement have been investigated experimentally. Extensive numerical simulations are performed to benchmark the performance of the proposed method.

  • Damage Development on the Surface of Nickel Coating in the Initial Period of Erosion
    • Dominika Zakrzewska
    • Marta Buszko
    • Alicja Krella
    • Anna Komenda
    • Grzegorz Mordarski
    • Robert P. Socha
    2021 Pełny tekst Materials

    The common occurrence of the phenomenon of cavitation in many industries and the multitude of factors affecting the resistance to cavitation erosion of used materials contribute to the search for methods and appropriate parameters of coating application that are able to minimize the effects of erosion. To determine the validity of the developed application parameters and the method used, cavitation studies and microscopic observations of the development of erosion during the cavitation test were carried out. There was a clear lack of incubation time and a linear increase in losses after 60 min of the test. Moreover, the damage observed during the test overlapped, widening the area of erosion and thus leading to damage to the integrity of the coating.

  • DATA JOURNALS AND DATA PAPERS IN VARIOUS RESEARCH AREAS AND SCIENTIFIC DISCIPLINES – BIBLIOMETRIC ANALYSIS BASED ON INCITES
    • Beata Adamczak
    2021 Pełny tekst TASK Quarterly

    The main aim of this work is to provide insight into a bibliometric analysis of Data Journals and Data Papers in terms of research areas, disciplines, publication year and country. In particular, we calculated many bibliometric indicators, especially: the number of publications and citations. Furthermore, this work also investigated the top 20 journals in which scientists published the largest number of Data Papers. It was found that the first Data Paper in Medical and Health Science was published in 2006. Our results indicate that about 64% of Data Papers are cited and about 30% of Data Papers are articles that have international co-authors. We also found that a significant number of Data Papers were published in top quartile (Q1) Open Access journals. Furthermore, most Data Papers were published in Multidisciplinary Sciences, followed by Biological Sciences, Earth and related Environmental Sciences as well as Computer and Information Sciences. Our analyses show that the largest number of Data Papers were published in journals with an Impact Factor ranging from 5 to 6. Additionally, the largest number of Data Papers were published in the USA, China, the United Kingdom, Italy and France. From the point of view of scientists, this work is needed because scientists can check information about journals in which they may publish research data. Moreover, they can find Data Journals with a high Impact Factor and MEiN points. This analysis is also interesting because scientists/publishers can compare the disciplines and countries in which researchers have published the greatest number of Data Papers. Finally, it is worth noting that this work gives insights into the various bibliometric indicators related to citations and the number of publications. This information can be useful for people associated with bibliometric analyses.

  • Data set generation at novel test-rig for validation of numerical models for modeling granular flows
    • Agata Widuch
    • Kari Myöhänen
    • Markku Nikku
    • Marcin Nowak
    • Adam Klimanek
    • Wojciech Adamczyk
    2021 Pełny tekst INTERNATIONAL JOURNAL OF MULTIPHASE FLOW

    Significant effort has been exerted on developing fast and reliable numerical models for modeling particulate flow; this is challenging owing to the complexity of such flows. To achieve this, reliable and high-quality experimental data are required for model development and validation. This study presents the design of a novel test-rig that allows the visualization and measurement of particle flow patterns during the collision of two particle streams. Valuable data sets are provided for the validation of numerical models dedicated to granular flows. The experimental work was conducted for three particle distributions and different configurations of the test rig setup. Additionally, a standard discrete element method for modeling particle transport was applied to the test-rig configuration and the effects of the material spring constant on the predicated flow patterns are investigated. An additional purpose of these simulations was also to collect necessary data for further collision model validation, developed based on a reduced-order technique.

  • DC and AC Conductivity, Biosolubility and Thermal Properties of Mg-Doped Na2O–CaO–P2O5 Glasses
    • Natalia Wójcik
    • Sharafat Ali
    • Jakub Karczewski
    • Bo Jonson
    • Michał Bartmański
    • Ryszard Barczyński
    2021 Pełny tekst Materials

    Bioactive glasses have recently been extensively used to replace, regenerate, and repair hard tissues in the human body because of their ability to bond with living tissue. In this work, the effects of replacing Na2O with MgO on the electrical, biosolubility, and thermal properties of the target glass 10Na2O–60P2O5–30CaO (in mol%) were investigated. The electrical properties of the glasses were studied with the impedance spectroscopy technique. At 473 K, DC conductivity values decreased from 4.21*10−11 to 4.21*10−12 S cm−1 after complete substitution of MgO for Na2O. All samples had a similar activation energy of the DC conduction process ~1.27 eV. Conduction mechanisms were found to be due to hop of ions: Na+, Mg2+, and probable H+. FTIR analysis showed that, as the Mg content increased, the Q2 unit (PO2‐) shifted towards higher wavenumbers. The proportion of Q3 unit (P2O5) decreased in the glass structure. This confirmed that the replacement of Na+ by Mg2+ was accompanied by concurrent polymerization of the calcium–phosphate glass network. The biosolubility test in the phosphate‐buffered saline solution showed that the magnesium addition enhanced the biosolubility properties of Na2O–CaO–P2O5 glasses by increasing their dissolution rate and supporting forming CaP‐rich layers on the surface. The glass transition temperature increased, and thermal stability decreased substantially upon substitution of Na2O by MgO.

  • Decoupled Kalman filter based identification of time-varying FIR systems
    • Marcin Ciołek
    • Maciej Niedźwiecki
    • Artur Gańcza
    2021 Pełny tekst IEEE Access

    When system parameters vary at a fast rate, identification schemes based on model-free local estimation approaches do not yield satisfactory results. In cases like this, more sophisticated parameter tracking procedures must be used, based on explicit models of parameter variation (often referred to as hypermodels), either deterministic or stochastic. Kalman filter trackers, which belong to the second category, are seldom used in practice due to difficulties in adjusting their internal parameters such as the smoothness coefficient and the order of the hypermodel. The paper presents a new solution to this problem, based on the concept of preestimation of system parameters. The resulting identification algorithms, which can be characterized as decoupled Kalman trackers, are computationally attractive, easy to tune and can be optimized in an adaptive fashion using the parallel estimation approach. The decoupled KF algorithms can be regarded as an attractive alternative to the state-of-the-art algorithms which are much more computationally demanding.

  • Deep eutectic solvent based method for analysis of Niclosamide in pharmaceutical and wastewater samples – A green analytical chemistry approach
    • Noor Faraz
    • Hameed Haq
    • Muhammad Balal
    • Roberto Castro-Muñoz
    • Grzegorz Boczkaj
    • Asif Khan
    2021 Pełny tekst JOURNAL OF MOLECULAR LIQUIDS

    The paper presents a simple, but very effective and sensitive spectrophotometric method for trace analysis of Niclosamide based on liquid–liquid microextraction using deep eutectic solvents (DESs) prior to its quantification. Here, different DES systems, such as Choline chloride (ChCl) + Urea, ChCl + Citric acid, ChCl + Ethylene glycol and ChCl + Phenol, were synthesized and evaluated at different molar ratios, selecting ChCl + Phenol 1:2 as an extractive DES system. Optimization studies revealed that best performance were obtained at pH 8 with optimum volume of THF and DES as 0.3 mL and 0.4 mL, respectively. The developed method is characterized by good analytical performance, e.g., a recovery of 99.26% and precision described by RSD value as <2%. The inter-assay precision was 0.51% while intermediate precision was 0.0323%. The method was found linear from 4.8 to 48 µg/L. LOD and LOQ were found as 0.112 and 0.374 µg/L, respectively. The paper presents also examples of the application of the proposed method for the determination of Niclosamide in different pharmaceutical and wastewater samples. This alternative method reveals a better performance in respect to the British pharmacopoeia procedure, providing concurrently ease of operation and simplicity.

  • Deep eutectic solvents – based green absorbents for effective volatile organochlorine compounds removal from biogas
    • Patrycja Makoś-Chełstowska
    • Edyta Słupek
    • Jacek Gębicki
    2021 Pełny tekst GREEN CHEMISTRY

    Volatile organochlorine compounds (VOXs) presented in biogas can cause many technological and environmental problems. During the combustion of biogas containing VOXs, the corrosion of installation, as well as the formation of toxic by-products (polyhalogenated dioxins and furans) and further emission to the atmosphere, may occur. Therefore, in this study, a new procedure based on physical absorption was developed. In order to meet the requirements of green chemistry and green engineering, new deep eutectic solvents (DESs) composed of natural components were used in the absorption studies. Several physical properties of new DESs were determined, followed by an explanation of the absorbents formation mechanism, by means of spectroscopic analysis, and density functional theory. The most important absorption parameters i.e. type of DES, gas flowrate, kind of matrix gas, temperature, and initial concentrations of VOXs were optimized. The obtained results indicate that DES composed of syringol and levulinic acid in 1:1 molar ratio could absorb VOXs efficiently. In addition, the DES regeneration studies demonstrated that the absorption capacities of DES did not change after ten absorption-desorption cycles. Studies on the absorption mechanisms indicate that the H-bonding and van der Waals interactions are the main driving force for the VOXs removal from biogas.

  • Deep eutectic solvents based assay for extraction and determination of zinc in fish and eel samples using FAAS
    • Hameed Haq
    • Muhammad Balal
    • Roberto Castro-Muñoz
    • Zahid Hussain
    • Faisal Safi
    • Sana Ullah
    • Grzegorz Boczkaj
    2021 Pełny tekst JOURNAL OF MOLECULAR LIQUIDS

    A new assay based on effective (high recovery) extraction by means of deep eutectic solvents (DESs) was developed for ppb level determination of zinc in fishes and eel samples. Choline chloride and Phenol in a 1:2 M ratio was selected as optimal DES-based extraction solvent. 8-Hydroxy quinoline was used as a chelating agent for zinc ions. The optimized conditions were found at pH value of 8, ligand concentration of 10 mg/L, THF volumetric ratio in bulk solution of 0.5:10. The total time at optimal sample preparation conditions was 5 min for digested sample. Developed method fits to the purpose of routine analysis of fishes and eels. The LOD and LOQ were found 0.041 μg/kg and 0.136 μg/kg with pre-concentration factor of 25 and RSD 1.7%.

  • Deep Learning
    • Semra Erpolat Tasabat
    • Olgun Aydin
    2021

    Deep learning (DL) is a rising star of machine learning (ML) and artificial intelligence (AI) domains. Until 2006, many researchers had attempted to build deep neural networks (DNN), but most of them failed. In 2006, it was proven that deep neural networks are one of the most crucial inventions for the 21st century. Nowadays, DNN are being used as a key technology for many different domains: self-driven vehicles, smart cities, security, automated machines. In this chapter, brief information about DL theory is given, advantages and disadvantages of deep learning are discussed, most used types of DNN are mentioned, popular DL architectures and frameworks are glanced and aimed to build smart systems for the finance and real estate domains. Finally, a case study about image recognition using transfer learning is developed.

  • Deep Learning: A Case Study for Image Recognition Using Transfer Learning
    • Semra Erpolat Tasabat
    • Olgun Aydin
    2021

    Deep learning (DL) is a rising star of machine learning (ML) and artificial intelligence (AI) domains. Until 2006, many researchers had attempted to build deep neural networks (DNN), but most of them failed. In 2006, it was proven that deep neural networks are one of the most crucial inventions for the 21st century. Nowadays, DNN are being used as a key technology for many different domains: self-driven vehicles, smart cities, security, automated machines. In this chapter, brief information about DL theory is given, advantages and disadvantages of deep learning are discussed, most used types of DNN are mentioned, popular DL architectures and frameworks are glanced and aimed to build smart systems for the finance and real estate domains. Finally, a case study about image recognition using transfer learning is developed.

  • Deep learning for ultra-fast and high precision screening of energy materials
    • Zhilong Wang
    • Qingxun Wang
    • Yanqiang Han
    • Yan Ma
    • Hua Zhao
    • Andrzej Nowak
    • Jinjin Li
    2021 Energy Storage Materials

    Semiconductor materials for energy storage are the core and foundation of modern information society and play important roles in photovoltaic system, integrated circuit, spacecraft technology, lighting applications, and other fields. Unfortunately, due to the long experiment period and high calculation cost, the high-precision band gap (the basic characteristic parameter) of semiconductor is difficult to obtain, which hinders the development of new semiconductor materials. Since the traditional Perdew–Burke–Ernzerhof (PBE) functional not only requires a long calculation time, but also significantly underestimates the band gap, we developed a deep learning model that can predict the more precise Heyd–Scuseria–Ernzerhof (HSE06) band gaps in milliseconds for 1,503 binary metallic oxides, nitrides, and sulfides, with a mean absolute error (MAE) of 0.35 eV, a mean squared error (MSE) of 0.21 eV, and a coefficient of determination (R 2 ) of 0.98. Based on transfer learning, only < 5% of the data set (64 structures) was required to train the model and predict the band gaps of the remaining 1,439 structures. From the 1,503 candidate materials, we quickly identified 75 carrier transport materials, 33 electrode and electrocatalytic materials, 299 power switching materials, and 114 sensing materials. This work is the first to demonstrate the feasibility of transfer learning in band gap prediction, from the low-level PBE to the high-level HSE06 calculation, with a computation speed at least 10 4 times faster than the ab initio calculation. The proposed method could be further expanded to incorporate entire organic/inorganic crystal materials databases ( > 10 6 crystals), which is of great significance for the screening and discovery of new semiconductor energy storage materials. 1.

  • Defining a novel domain that provides an essential contribution to site-specific interaction of Rep protein with DNA
    • Katarzyna Wegrzyn
    • Elzbieta Zabrocka
    • Katarzyna Bury
    • Bartlomiej Tomiczek
    • Miłosz Wieczór
    • Jacek Czub
    • Urszula Uciechowska
    • María Moreno-del Alamo
    • Urszula Walkow
    • Igor Grochowina
    • Rafal Dutkiewicz
    • Janusz M. Bujnicki
    • Rafael Giraldo
    • Igor Konieczny
    2021 Pełny tekst NUCLEIC ACIDS RESEARCH

    An essential feature of replication initiation proteins is their ability to bind to DNA. In this work, we describe a new domain that contributes to a replication initiator sequence-specific interaction with DNA. Applying biochemical assays and structure prediction methods coupled with DNA–protein crosslinking, mass spectrometry, and construction and analysis of mutant proteins, we identified that the replication initiator of the broad host range plasmid RK2, in addition to two winged helix domains, contains a third DNA-binding domain. The phylogenetic analysis revealed that the composition of this unique domain is typical within the described TrfA-like protein family. Both in vitro and in vivo experiments involving the constructed TrfA mutant proteins showed that the newly identified domain is essential for the formation of the protein complex with DNA, contributes to the avidity for interaction with DNA, and the replication activity of the initiator. The analysis of mutant proteins, each containing a single substitution, showed that each of the three domains composing TrfA is essential for the formation of the protein complex with DNA. Furthermore, the new domain, along with the winged helix domains, contributes to the sequence specificity of replication initiator interaction within the plasmid replication origin.

  • Defining the smart-city in the context of regenerative design and planning
    • Dorota Kamrowska-Załuska
    • Gerald Leindecker
    • Marielle Ferreira SILVA
    • Gulben Calis
    • Aleksandar Petrovski
    2021

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  • Defining the thermal conductivity of thermally heterogeneous hollow wall bricks used as elements for increasing the comfort of buildings
    • Krzysztof Pawłowski
    • Maciej Niedostatkiewicz
    2021 Pełny tekst Inżynieria Bezpieczeństwa Obiektów Antropogenicznych

    The article presents numerical calculation analysis in the scope of determining thermal conductivity coefficientλeq[W/(m·K)] of thermally heterogeneous hollow bricks of thermally heterogeneous structure (a combinationof structural material with thermal insulation material). Numerical calculations were conducted by means ofprofessional software TRISCO-KOBRU 86, serving thermal circulation analysis in a 2D field in stationary approach.The analyzed hollow wall bricks may be used, for instance, as a structural layer of layered outer walls of a building.In the article also the results of the Uc thermal conductivity coefficient calculations for double-layer walls with theuse of the analyzed hollow wall bricks are presented in regard to thermal requirements.

  • Definiowany programowo uniwersalny interfejs radiowy inteligentnych urządzeń internetu rzeczy
    • Olga Błaszkiewicz
    • Jarosław Magiera
    • Alicja Olejniczak
    • Piotr Rajchowski
    • Jarosław Sadowski
    • Sławomir Ambroziak
    • Krzysztof Cwalina
    2021 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    Intensywny wzrost liczby urządzeń komunikujących się ze sobą na dużym obszarze wymaga opracowywania i realizacji rozwiązań systemowych. Z tego względu organizacja 3GPP zdefiniowała wąskopasmowy interfejs radiowy NB-IoT (Narrowband Internet of Things) będący podsystemem LTE (Long Term Evolution) na potrzeby zastosowań IoT niewymagających dużych przepływności. W niniejszym artykule przedstawiono charakterystykę systemu NB-IoT, a także koncepcję i sposób realizacji opracowywanego definiowanego programowo, uniwersalnego, sprzętowo-programowego frameworku wraz z laboratoryjnym środowiskiem badawczo-pomiarowym. W aktualnym etapie prac zaimplementowano większość warstwy fizycznej łącza w dół i w górę oraz wybrane elementy sterowania dostępem do medium transmisyjnego, które zweryfikowano z użyciem testera radiowego.

  • Denitrification Process Enhancement and Diversity of the Denitrifying Community in the Full Scale Activated Sludge System after Adaptation to Fusel Oil
    • Przemysław Kowal
    • Sławomir Ciesielski
    • Jeremiah Otieno
    • Joanna Majtacz
    • Krzysztof Czerwionka
    • Jacek Mąkinia
    2021 Pełny tekst ENERGIES

    Implementation of anaerobic digestion of primary sludge in modern wastewater treatment plants (WWTPs) limits the availability of organic carbon for denitrification in conventional nitrification-denitrification (N/DN) systems. In order to ensure efficient denitrification, dosage of the external carbon source is commonly undertaken. However, application of commercial products, such us ethanol or acetate, greatly increases operational costs. As such, inexpensive and efficient alternative carbon sources are strongly desirable. In this study, the use of the fusel oil, a by-product from the distillery industry, was validated in terms of the denitrification process enhancement and impact on the activated sludge bacterial community structure. The experiment was conducted at a full scale biological nutrient removal facility (210,000 PE), in the set of the two technological lines: the experimental line (where fusel oil was introduced at 45 cm3/m3 dose) and the reference line (without an external carbon source addition). During the experimental period of 98 days, conventional nitrate utilization rate (NUR) measurements were carried out on a regular basis in order to assess the biomass adaptation to the fusel oil addition and denitrification process enhancement. While the NURs remained at a stable level in the reference line (1.4 ± 0.1 mg NO3-N/g VSS·h) throughout the entire duration of the experiment, the addition of fusel oil gradually enhanced the denitrification process rate up to 2.7 mg NO3-N/g VSS·h. Moreover, fusel oil contributed to the mitigation of the variability of NO3-N concentrations in the effluent from the anoxic zone. The bacterial community structure, characterized by 16S rRNA PCR—DGGE and the clone libraries of the genes involved in the denitrification process (nirS and nirK), was comparable between the reference and the experimental line during the entire experimental period. In both analyzed lines, the most frequent occurrence of denitrifiers belonging to the genera Acidovorax, Alcaligenes, Azoarcus, Paracoccus and Thauera was noticed. Our results proved that fusel oil would a valuable substrate for denitrification. The addition of fusel oil enhances the process rate and does not reflect a severe selection pressure on the bacterial community at applicable doses. Practical application of fusel oil generates opportunities for the WWTPs to meet effluent standards and reduce operational costs and optimizing waste management for distillery industry.

  • Dependence of Power Characteristics on Savonius Rotor Segmentation
    • Krzysztof Doerffer
    • Janusz Telega
    • Piotr Doerffer
    • Paulina Hercel
    • Andrzej Tomporowski
    2021 Pełny tekst ENERGIES

    Savonius rotors are large and heavy because they use drag force for propulsion. This leads to a larger investment in comparison to horizontal axis wind turbine (HAWT) rotors using lift forces. A simple construction of the Savonius rotor is preferred to reduce the production effort. Therefore, it is proposed here to use single-segment rotors of high elongation. Nevertheless, this rotor type must be compared with a multi-segment rotor to prove that the simplification does not deteriorate the effectiveness. The number of segments affects the aerodynamic performance of the rotor, however, the results shown in the literature are inconsistent. The paper presents a new observation that the relation between the effectiveness of single- and multi-segment rotors depends on the wind velocity. A single-segment rotor becomes significantly more effective than a four-segment rotor at low wind speeds. At high wind speeds, the effectiveness of both rotors becomes similar.

  • Design and computational fluid dynamics analysis of the last stage of innovative gas-steam turbine
    • Stanisław Głuch
    • Paweł Ziółkowski
    • Łukasz Witanowski
    • Janusz Badur
    2021 Pełny tekst Archives of Thermodynamics

    Research regarding blade design and analysis of flow has been attracting interest for over a century. Meanwhile new concepts and design approaches were created and improved. Advancements in information technologies allowed to introduce computational fluid dynamics and computational flow mechanics. Currently a combination of mentioned methods is used for the design of turbine blades. These methods enabled us to improve flow efficiency and strength of turbine blades. This paper relates to a new type turbine which is in the phase of theoretical analysis, because the working fluid is a mixture of steam and gas generated in a wet combustion chamber. The main aim of this paper is to design and analyze the flow characteristics of the last stage of gas-steam turbine. When creating the spatial model, the atlas of profiles of reaction turbine steps was used. Results of computational fluid dynamics simulations of twisting of the last stage are presented. Blades geometry and the computational mesh are also presented. Velocity vectors, for selected dividing sections that the velocity along the pitch diameter varies greatly. The blade has the shape of its cross-section similar to action type blades near the root and to reaction type blades near the tip. Velocity fields and pressure fields show the flow characteristics of the last stage of gas-steam turbine. The net efficiency of the cycle is equal to 52.61%.

  • Design and experimental validation of a single-stage PV string inverter with optimal number of interleaved buck-boost cells.
    • Artem Fesenko
    • Oleksandr Matiushkin
    • Oleksandr Husev
    • Dmitri Vinnikov
    • Ryszard Strzelecki
    • Piotr Kołodziejek
    2021 Pełny tekst ENERGIES

    Increasing converter power density is a problem of topical interest. This paper discusses an interleaved approach of the efficiency increase in the buck-boost stage of an inverter with unfolding circuit in terms of losses in semiconductors, output voltage ripples and power density. Main trends in the power converter development are reviewed. A losses model was designed and used for the proposed solution to find an optimal number of interleaved cells. It describes static and dynamic losses in semiconductor switches for buck and boost mode. The presented calculation results demonstrate the efficiency of the interleaved approach for photovoltaic system. 1 kW power converter prototype was designed with two parallel dc-dc cells for experimental verification of obtained theoretical results. The experimental results confirm theoretical statements.

  • Design and implementation of an illumination system to mimic skyglow at ecosystem level in a large‐scale lake enclosure facility
    • Andreas Jechow
    • Günther Schreck
    • Christopher C. M. Kyba
    • Stella A. Berger
    • Lukas Thuile Bistarelli
    • Matthias Bodenlos
    • Mark O. Gessner
    • Hans‐Peter Grossart
    • Franziska Kupprat
    • Jens C. Nejstgaard
    • Andreas Pansch
    • Armin Penske
    • Michael Sachtleben
    • Tom Shatwell
    • Gabriel A. Singer
    • Susanne Stephan
    • Tim J. W. Walles
    • Sabine Wollrab
    • Karolina Zielińska-Dąbkowska
    • Franz Hölker
    2021 Pełny tekst Scientific Reports

    Light pollution is an environmental stressor of global extent that is growing exponentially in area and intensity. Artificial skyglow, a form of light pollution with large range, is hypothesized to have environmental impact at ecosystem level. However, testing the impact of skyglow at large scales and in a controlled fashion under in situ conditions has remained elusive so far. Here we present the first experimental setup to mimic skyglow at ecosystem level outdoors in an aquatic environment. Spatially diffuse and homogeneous surface illumination that is adjustable between 0.01 and 10 lx, resembling rural to urban skyglow levels, was achieved with white light‐emitting diodes at a large‐ scale lake enclosure facility. The illumination system was enabled by optical modeling with Monte‐ Carlo raytracing and validated by measurements. Our method can be adapted to other outdoor and indoor skyglow experiments, urgently needed to understand the impact of skyglow on ecosystems.

  • Design and implementation of the driver system for Hamamatsu C12880MA microspectrometer
    • Patryk Sokołowski
    • Maciej Wróbel
    • Katarzyna Karpienko
    2021 Pełny tekst Photonics Letters of Poland

    Recent miniaturization developments in devices for spectroscopy have reduced greatly their costs and increased their availability for a wide range of users and applications. This paper presents the design and implementation of a driver system for a Hamamatsu C12880MA microspectrometer. The system implementation was carried out and compared using two independent microcontroller modules: Arduino Uno and STM32F411RE Nucleo. We assessed the microspectrometer system parameters like resolution and integration time, as influenced by the choice of a driver icrocontroller. We present a possible application of this microspectrometer system for measurements of ground coffee beans reflectance for control of coffee roasting.

  • Design centering of compact microwave components using response features and trust regions
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    2021 Pełny tekst ENERGIES

    Fabrication tolerances, as well as uncertainties of other kinds, e.g., concerning material parameters or operating conditions, are detrimental to the performance of microwave circuits. Mitigating their impact requires accounting for possible parameter deviations already at the design stage. This involves optimization of appropriately defined statistical figures of merit such as yield. Alt-hough important, robust (or tolerance-aware) design is an intricate endeavor because manufac-turing inaccuracies are normally described using probability distributions, and their quantification has to be based on statistical analysis. The major bottleneck here is high computational cost: for re-liability reasons, miniaturized microwave components are evaluated using full-wave electromag-netic (EM) models, whereas conventionally utilized analysis methods (e.g., Monte Carlo simula-tion) are associated with massive circuit evaluations. A practical approach that allows for cir-cumventing aforementioned obstacles offer surrogate modeling techniques, which has been a dominant trend over the recent years. Notwithstanding, a construction of accurate metamodels may require considerable computational investments, especially for higher-dimensional cases. This paper brings in a novel design centering approach, which assembles forward surrogates founded at the level of response features and trust-region framework for direct optimization of the system yield. Formulating the problem with the use of characteristic points of the system response allevi-ates the issues related to response nonlinearities. At the same time, as the surrogate is a linear re-gression model, a rapid yield estimation is possible through numerical integration of the input probability distributions. As a result, expenditures related to design centering are as low as a few dozens of EM analyses. The introduced technique is demonstrated using three microstrip couplers. It is compared to recently reported techniques, and its reliability is corroborated using EM-based Monte Carlo analysis.

  • Design Evolution of the Ultrasonic Piezoelectric Motor Using Three Rotating Mode Actuators
    • Roland Ryndzionek
    • Łukasz Sienkiewicz
    • Michał Michna
    • Marek Chodnicki
    2021 Pełny tekst IEEE Access

    The development process and experimental investigation of the multicell piezoelectric motor is presented in this paper. The proposed design consists of three individual cells integrated into the stator, double rotor, and a preload system. Those elements are combined into a symmetrical structure of the motor. The two new prototypes have been designed, simulated and tested. Finite element numerical analysis is carried out to obtain optimal dimensions of the individual cell in terms of generated vibrations and resonant frequencies of the structure. The results of the numerical analysis are compared with analytical calculations based on the equivalent circuit model. The stator of the motor was manufactured using a three-dimensional (3-D) printer using alumide material. Finally, the experimental tests were conducted and presented. Analytical, numerical and experimental results are in satisfactory agreement. Two new prototypes of the multicell piezoelectric motor exhibit torque-speed characteristics similar to the original while being cheaper and easier to manufacture.