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Gdańsk University of Technology

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  • Binary-Encounter Model for Direct Ionization of Molecules by Positron-Impact
    • Małgorzata Franz
    • Katarzyna Wiciak-Pawłowska
    • Jan Franz
    2021 Full text Atoms

    We introduce two models for the computation of direct ionization cross sections by positron impact over a wide range of collision energies. The models are based on the binary-encounter-Bethe model and take into account an extension of the Wannier theory. The cross sections computed with these models show good agreement with experimental data. The extensions improve the agreement between theory and experiment for collision energies between the first ionization threshold and the peak of the cross section. The models are based on a small set of parameters, which can be computed with standard quantum chemistry program packages.

  • BINDER COURSES USING COLD RECYCLED MIXTURES – A NOVEL CONCEPT IN COLD RECYCLING
    • Bohdan Dołżycki
    • Andrea Grilli
    • Alex Balzi
    • Mariusz Jaczewski
    • Cezary Szydłowski
    2021

    Cold recycling with cement and bituminous emulsion is one of the most environmentally friendly techniques to maximize the reuse of reclaimed asphalt (RA) collected during demolition of roads. Cold recycled mixtures are commonly used for base courses in construction or rehabilitation of flexible and semi-rigid pavements. Current experiences demonstrated that cold recycling with appropriate requirements and technical recommendations allows long-lasting pavements to be designed. Those outcomes stimulated researchers and engineers in the new challenge of using the cold recycled mixtures in binder layers that are generally more often included in maintenance planning. This paper summarizes current San Marino and Polish experiences with cold recycled mixtures designed for binder layers. The first part of the paper presents the design phase of the cold recycled mixtures in both countries. It describes and compares the composition of the mixtures, grading curves of the mineral mixtures, binding agents and requirements. The second part of the paper shows laboratory test results of mechanical properties of cold recycled mixtures for binder courses including test results in full-scale application.

  • Bioactivities of Phenolic Compounds from Kiwifruit and Persimmon
    • Kim Young-mo
    • Abas Faridah
    • Yong-Seo Park
    • Ang-Kyun Park
    • Kyung-Sik Ham
    • Seong-Gook Kang
    • Martyna Lubinska-Szczygeł
    • Aviva Ezra
    • Shela Gorinstein
    2021 Full text MOLECULES

    Fruit used in the common human diet in general, and kiwifruit and persimmon particularly, displays health properties in the prevention of heart disease. This study describes a combination of bioactivity, multivariate data analyses and fluorescence measurements for the differentiating of kiwifruit and persimmon, their quenching and antioxidant properties. The metabolic differences are shown, as well in the results of bioactivities and antioxidant capacities determined by ABTS, FRAP, CUPRAC and DPPH assays. To complement the bioactivity of these fruits, the quenching properties between extracted polyphenols and human serum proteins were determined by 3D-fluorescence spectroscopy studies. These properties of the extracted polyphenols in interaction with the main serum proteins in the human metabolism (human serum albumin (HSA), α-β-globulin (α-β G) and fibrinogen (Fgn)), showed that kiwifruit was more reactive than persimmon. There was a direct correlation between the quenching properties of the polyphenols of the investigated fruits with serum human proteins, their relative quantification and bioactivity. The results of metabolites and fluorescence quenching show that these fruits possess multiple properties that have a great potential to be used in industry with emphasis on the formulation of functional foods and in the pharmaceutical industry. Based on the quenching properties of human serum proteins with polyphenols and recent reports in vivo on human studies, we hypothesize that HSA, α-β G and Fgn will be predictors of coronary artery disease (CAD).

  • Bio-Based Polyurethane Networks Derived from Liquefied Sawdust
    • Kamila Gosz
    • Agnieszka Tercjak
    • Adam Olszewski
    • Józef Haponiuk
    • Łukasz Piszczyk
    2021 Full text Materials

    The utilization of forestry waste resources in the production of polyurethane resins is a promising green alternative to the use of unsustainable resources. Liquefaction of wood-based biomass gives polyols with properties depending on the reagents used. In this article, the liquefaction of forestry wastes, including sawdust, in solvents such as glycerol and polyethylene glycol was investigated. The liquefaction process was carried out at temperatures of 120, 150, and 170 C. The resulting bio-polyols were analyzed for process efficiency, hydroxyl number, water content, viscosity, and structural features using the Fourier transform infrared spectroscopy (FTIR). The optimum liquefaction temperature was 150 C and the time of 6 h. Comprehensive analysis of polyol properties shows high biomass conversion and hydroxyl number in the range of 238–815 mg KOH/g. This may indicate that bio-polyols may be used as a potential substitute for petrochemical polyols. During polyurethane synthesis, materials with more than 80 wt% of bio-polyol were obtained. The materials were obtained by a one-step method by hot-pressing for 15 min at 100 C and a pressure of 5 MPa with an NCO:OH ratio of 1:1 and 1.2:1. Dynamical-mechanical analysis (DMA) showed a high modulus of elasticity in the range of 62–839 MPa which depends on the reaction conditions.

  • Biofilm bakteryjny uropatogennych szczepów E. coli Dr+ jako czynnik indukujący przewlekłość zakażeń dróg moczowych ograniczający ich leczenie
    • Beata Zalewska-Piątek
    • Rafał Piątek
    2021 Postępy Mikrobiologii

    Zakażenia dróg moczowych (ZUM) stanowią jedne z najczęściej występujących infekcji bakteryjnych, dotykających każdego roku miliony osób na świecie. Problematyka tych zakażeń wynika z ich przewlekłości i nawrotów, pomimo stosowania terapii antybiotykowej oraz ciągle wzrastającej lekooporności uropatogenów je wywołujących. Dominującym czynnikiem etiologicznym ZUM są uropatogenne szczepy E. coli (UPECs), wykazujące zdolność do adhezji, inwazji, tworzenia wewnątrzkomórkowych agregatów bakteryjnych i złożonych struktur biofilmu w obrębie skolonizowanych dróg moczowych. Szczepy E. coli Dr+ stanowią trzecią grupę UPECs, które produkują homopolimeryczne struktury adhezyjne, występujące na powierzchni komórek bakteryjnych w postaci fimbrii Dr. Są one odpowiedzialne za zapalenie pęcherza moczowego u dzieci i odmiedniczkowe zapalenie nerek u dorosłych, zwłaszcza u kobiet ciężarnych (40% przypadków, w III trymestrze ciąży). Zdolność do tworzenia biofilmu stanowi również przyczynę przewlekłości tych zakażeń i trudności terapeutyczne. W toku prowadzonych badań wykazano, że fimbrie Dr i białko DraD stanowią główne determinanty urowirulencji klinicznego izolatu E. coli IH11128 Dr+, odpowiedzialne za tworzenie biofilmu, natomiast autoagregująca adhezyna Ag43 może wpływać na jego rozwój i zwiększenie przeżywalności bakterii w komórkach uroepitelialnych. Wstępne analizy wykazały również, że bakterie te wzrastające na podłożu polistyrenowym, tworzą biofilm o rozgałęzionej, drzewiastej strukturze z komórkami uwięzionymi w rozległej macierzy pozakomórkowej. Powyższe dane eksperymentalne wymagają jednak dalszych badań, dotyczących struktury i składu biochemicznego biofilmu, w odniesieniu do aktywności metabolicznej komórek bakteryjnych.

  • Bio-inspired approaches for explosives detection
    • Wasilewski Tomasz
    • Jacek Gębicki
    • Wojciech Kamysz
    2021 Full text TRAC-TRENDS IN ANALYTICAL CHEMISTRY

    Due to unique abilities of the animals regarding analysis of complex gas substances, they still remain a gold standard in analysis of explosives. Unusual capabilities of biological chemosensory systems, including both vertebrates and invertebrates, stimulate elaboration of the devices mimicking their activity and operation parameters as precisely as possible. The electronic analogues are a subject of investigation in many research centres, which brings their successful commercialization closer. They are believed to substitute or to complement animals in the analysis of gas substances, including explosive and hazardous ones. The limitations of classic gas sensors can be overcome using the strategies inspired by the solutions known from biological systems. Apart from high selectivity and sensitivity desired for analysis of the explosives, mimicking biological systems allows overcoming other problems connected mainly with effective sampling and odour localization. Presented review is focused on the biomimetic devices, which mimic the sense of smell in a direct way and which are the inspiration to design the devices used for detection of the explosives. Potential of biosensors and bioelectronic noses (B-ENs) to mimic the incredibly accurate and versatile "biological noses" was evaluated. A summary of the strategies inspired by biological olfactory systems should facilitate the approach to the problem of artificial instruments design and to development of the strategy aimed at analysis of the explosives with these systems.

  • BIOLOGICAL AGE ASSESSMENT ALGORITHMS BASED ON X-RAY IMAGES OF BONE TISSUE
    • Natalia Głowacka
    2021

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  • Biologically active compounds based on the carbazole scaffold - synthetic and mechanistic aspects
    • Milena Witkowska
    2021 Full text

    Doctoral dissertation is divided into three main parts: introduction, results and discussion and experimental. The introduction is divided into four main parts which describe: 5-hydroxytryptamine receptors, the most popular antidepressants, new compounds based on the carbazole structure with affinity for serotonin receptors, telomeres and telomerase with their functions, telomerase inhibition strategies, carbazoles approved in cancer treatment, new carbazole derivatives which are telomerase inhibitors and selected methods of synthesis tetrahydrocarbazole and carbazole derivatives. The main part of the work are results and discussion. In this chapter the effects of experiments in the synthesis of 1,2,3,4-tetrahydrocyclopenta[b]indoles, 1,2,4-trisubstituted carbazole derivatives and 1,2,3,6-tetrasubstituted carbazole derivatives are described. The experimental part includes procedures for the preparation of compounds, spectral analysis of products and a list of instruments that were used in the implementation of this work.

  • Biomass in biogas production: Pretreatment and codigestion
    • Archana Kasinath
    • Sylwia Fudala-Książek
    • Małgorzata Szopińska
    • Hubert Byliński
    • Wojciech Artichowicz
    • Anna Remiszewska-Skwarek
    • Aneta Łuczkiewicz
    2021 Full text RENEWABLE & SUSTAINABLE ENERGY REVIEWS

    Globally, there is increasing awareness that the implementation of ‘waste to energy’ technology is one of the best means to achieve sustainable energy development. The most popular approach is the conversion of organic-rich compounds into clean and renewable products by anaerobic digestion (AD). Biogas can be produced from agricultural residues, municipal/industrial biowastes, and sustainable biomass, especially materials that are locally available. However, in many cases, the methane yields obtained from the conventional AD process are regarded as having limited profitability. This paper summarizes the recent knowledge regarding the different strategies that are used to enhance AD efficiency and the methods to strengthen the existing incentives to overcome today's barriers to biogas production. Special attention was given to several approaches used to improve the biodegradability of organic matter and the methane potential of feedstocks, mainly codigestion and pretreatment of single/mixed substrates. The statistical analyses indicated enormous variability among biogas systems, thus, there is a need for unification of the methods applied for process control and the parameters used for the discussion of results. A synchronized methodology is also needed to understand the environmental advantages and drawbacks of selected utilization pathways in biogas production. Currently, the underestimated potential of AD is of growing interest, and pretreatment/codigestion can directly increase the effectiveness of this technology and lead to its optimization. Nonetheless, a proper evaluation of the environmental (e.g., sustainable biomass) and social (e.g., bioaerosol nuisance) aspects is also needed.

  • Biomass Production and Removal of Nitrogen and Phosphorus from Processed Municipal Wastewater by Salix schwerinii: A Field Trial
    • Muhammad Mohsin
    • Erik Kaipiainen
    • Mir Md Abdus Salam
    • Nikolai Evstishenkov
    • Nicole Nawrot
    • Aki Villa
    • Ewa Wojciechowska
    • Suvi Kuittinen
    • Ari Pappinen
    2021 Full text Water

    In many Baltic regions, short-rotation willow (Salix spp.) is used as a vegetation filter for wastewater treatment and recycling of valuable nutrients to upsurge bioeconomy development. In this context, a four-year field trial (2016–2019) was carried out near a wastewater treatment plant in eastern Finland (Outokumpu) to investigate the effect of the processed wastewater (WW) on biomass production as well as the nutrients uptake capability (mainly N and P) by a willow variety (Salix schwerinii). Results indicated that WW irrigation expressively increased the willow diameter growth and biomass yield around 256% and 6510%, respectively, compared to the control treatment site (without WW). The willow was also able to accumulate approximately 41–60% of the N and 32–50% of the P in two years (2018–2019). Overall, willow showed a total 20% mortality rate under WW irrigation throughout the growing periods (2017–2019) as compared to control (39%). The results demonstrate that willow has the potential to control eutrophication (reducing nutrients load) from the wastewater with the best survival rate and can provide high biomass production for bioenergy generations in cold climatic conditions.

  • Biomass-Derived Nitrogen Functionalized Carbon Nanodots and Their Anti-Biofouling Properties
    • Maria Rybarczyk
    • Emilia Gontarek-Castro
    • Karolina Ollik
    • Marek Lieder
    2021 Full text Processes

    The prevalence of the antibiotic resistant bacteria remains a global issue. Cheap, sustainable and multifunctional antibacterial membranes are at the forefront of filtrating materials capable of treating multiple flow streams, such as water cleansing treatments. Carbon nanomaterials are particularly interesting objects shown to enhance antibacterial properties of composite materials. In this article, amino-functionalized, photoluminescent carbon nanodots (CNDs) were synthesized from chitosan by bottom-up approach via simple and green hydrothermal carbonization. A chemical model for the CNDs formation during hydrothermal treatment of chitosan is proposed. The use of urea as an additional nitrogen source leads to the consumption of hydroxyl groups of chitosan and higher nitrogen doping level as pyridinic and pyrrolic N-bonding configurations in the final carbonaceous composition. These functionalized carbon nanodots that consist of carbon core and various surface functional groups were used to modify the commercially available membranes in order to enhance their anti-biofouling properties and add possible functionalities, including fluorescent labelling. Incorporation of CNDs to membranes increased their hydrophilicity, surface charge without compromising membranes integrity, thereby increasing the factors affecting bacterial wall disruption. Membranes modified with CNDs effectively stopped the growth of two Gramnegative bacterial colonies: Klebsiella oxytoca (K. oxytoca) and Pseudomonas aeruginosa (P. aeruginosa).

  • Biomechanics of Lumbar Spine Injury in Road Barrier Collision–Finite Element Study
    • Łukasz Pachocki
    • Karol Daszkiewicz
    • Piotr Łuczkiewicz
    • Wojciech Witkowski
    2021 Full text Frontiers in Bioengineering and Biotechnology

    Literature and field data from CIREN database have shown that lumbar spine injuries occur during car crashes. There are multiple hypotheses regarding how they occur; however, there is no biomechanical explanation for these injuries during collisions with road safety barriers (RSBs). Therefore, the objective of this study was to investigate the mechanics of vertebral fractures during car collisions with concrete RSBs. The finite element method was used for the numerical simulations. The global model of the car collision with the concrete RSB was created. The lumbar spine kinematics were extracted from the global simulation and then applied as boundary conditions to the detailed lumbar spine model. The results showed that during the collision, the occupant was elevated, and then dropped during the vehicle landing. This resulted in axial compression forces 2.6 kN with flexion bending moments 34.7 and 37.8 Nm in the L2 and L3 vertebrae. It was shown that the bending moment is the result of the longitudinal force on the eccentricity. The lumbar spine index for the L1–L5 section was 2.80, thus indicating a lumbar spine fracture. The minimum principal strain criterion of 7.4% and damage variable indicated L2 and L3 vertebrae and the inferior part of L1, as those potentially prone to fracture. This study found that lumbar spine fractures could occur as a consequence of vehicle landing during a collision with a concrete RSB mostly affecting the L1–L3 lumbar spine section. The fracture was caused by a combination of axial forces and flexion bending moments.

  • Biomechanics of the medial meniscus in the osteoarthritic knee joint
    • Karol Daszkiewicz
    • Piotr Łuczkiewicz
    2021 Full text PeerJ

    Background. Increased mechanical loading and pathological response of joint tissue to the abnormal mechanical stress can cause degradation of cartilage characteristic of knee osteoarthritis (OA). Despite osteoarthritis is risk factor for the development of meniscal lesions the mechanism of degenerative meniscal lesions is still unclear. Therefore, the aim of the study is to investigate the influence of medial compartment knee OA on the stress state and deformation of the medial meniscus. Methods. The finite element method was used to simulate the stance phase of the gait cycle. An intact knee model was prepared based on magnetic resonance scans of the left knee joint of a healthy volunteer. Degenerative changes in the medial knee OA model were simulated by nonuniform reduction in articular cartilage thickness in specific areas and by a decrease in the material parameters of cartilage and menisci. Two additional models were created to separately evaluate the effect of alterations in articular cartilage geometry and material parameters of the soft tissues on the results. A nonlinear dynamic analysis was performed for standardized knee loads applied to the tibia bone. Results. The maximum von Mises stress of 26.8 MPa was observed in the posterior part of the medial meniscus body in the OA model. The maximal hoop stress for the first peak of total force was 83% greater in the posterior horn and only 11% greater in the anterior horn of the medial meniscus in the OA model than in the intact model. The reduction in cartilage thickness caused an increase of 57% in medial translation of the medial meniscus body. A decrease in the compressive modulus of menisci resulted in a 2.5-fold greater reduction in the meniscal body width compared to the intact model. Conclusions. Higher hoop stress levels on the inner edge of the posterior part of the medial meniscus in the OA model than in the intact model are associated with a greater medial translation of the meniscus body and a greater reduction in its width. The considerable increase in hoop stresses shows that medial knee OA may contribute to the initiation of meniscal radial tears.

  • BIOMEDICAL ENGINEERING EDUCATION IN POLAND - PIONEERS AND INSTITUTIONS
    • Antoni Nowakowski
    2021

    The aim of this chapter is to show the history of biomedical engineering education in Poland, from the beginning till today with special task to underline the role of modern information technology. This story is not very old, just around one century, that may be classified into four basic periods related to important historic events. First are the beginnings before the second world war. Then post-war recovery and development of fundamentals, this is the period from 1946 till around 1970. The third period, till the change of political system in Poland in “nineties”, may be called formation of multicentre knowledge based education. Finally, from ca 1995, development of modern biomedical engineering education supported by “explosion” of information technologies. Each period is here characterised. Many data are given based on personal memory as the author was privileged to know almost all pioneers involved in biomedical engineering education in Poland and participated in many important events/moments of institutions involved in development of modern biomedical engineering.

  • Bistability in a One-Dimensional Model of a Two-Predators-One-Prey Population Dynamics System
    • Sergey Kryzhevich
    • Viktor Avrutin
    • Gunnar Sӧderbacka
    2021 Full text Lobachevskii Journal of Mathematics

    In this paper, we study a classical two-predators-one-prey model. The classical model described by a system of three ordinary differential equations can be reduced to a one-dimensional bimodalmap. We prove that this map has at most two stable periodic orbits. Besides, we describe the bifurcation structure of the map. Finally, we describe a mechanism that leads to bistable regimes. Taking this mechanism into account, one can easily detect parameter regions where cycles with arbitrary high periods or chaotic attractors with arbitrary high numbers of bands coexist pairwise.

  • Block graphs with large paired domination multisubdivision number
    • Christina M. Mynhardt
    • Joanna Raczek
    2021 Full text Discussiones Mathematicae Graph Theory

    The paired domination multisubdivision number of a nonempty graph G, denoted by msdpr(G), is the smallest positive integer k such that there exists an edge which must be subdivided k times to increase the paired domination number of G. It is known that msdpr(G) ≤ 4 for all graphs G. We characterize block graphs with msdpr(G) = 4.

  • Blockchain technologies to address smart city and society challenges
    • Julian Szymański
    • Higinio Mora
    • Julio Mendoza-Tello
    • Erick Varela-guzmán
    2021 COMPUTERS IN HUMAN BEHAVIOR

    New Information and Communications Technologies (ICT) are changing the way in which the world works. These technologies provide new tools to face the issues of contemporary society (poverty, migrations, sustainable development challenges, governance, etc.). Among them, blockchain emerge as a disruptive technology able to make things in a completely different and innovative way. They can provide solutions where before there were none. Recently, these technologies have become subject of intense research and development by industry and academia. In consequence, a large amount of interesting works is published in many areas, proposing solutions, services, frameworks and applications based on these technologies. The research focusing on the previous challenges are especially interesting in current society. However, the proposals arrive at higher speed than society can assimilate them, and sometimes they are not properly exploited. Thus, this paper provides a comprehensive overview of the blockchain technology to identify what are its key attributes that enable to successfully address the social challenges. The review has been conducted from three point of views: service-delivery, resource-management and city-administration, and has been focused on the Sustainable Development Goals of the United Nations, in order to cover the full agenda of current social issues. The contributions of this work are an exhaustive compilation of the existing research on blockchain technology to tackle the social challenges from several angles, and the identification of the key features and the conditioning factors of the practical applicability of the technology.

  • Blockchain: zdecentralizowane zaufanie
    • Stanisław Barański
    2021

    Bitcoin wprowadził innowację na wielu płaszczyznach. Jako pierwszy rozwiązał problem osiągania konsensusu w sieciach otwartych, stworzył zagadkę ekonomiczną w postaci globalnej waluty deflacyjnej, pozwolił na transfer pieniędzy tym, którzy wcześniej byli wykluczeni bankowo, ale przede wszystkim stworzył fundamenty pod platformę zdecentralizowanego zaufania. Zapoczątkował technologie zdecentralizowanych aplikacji, które dotychczas nie mogły istnieć bez zaufanej trzeciej strony. W pracy opisana została ta ostatnia płaszczyzna.

  • Błedy realizacji prac remontowych przyczyną uszkodzeń wilgotnościowych zabytkowego budynku sali BHP w Gdańsku
    • Maciej Niedostatkiewicz
    2021 Full text Builder

    W artykule przedstawiono opis uszkodzeń wilgotnościowych występujących w historycznym budynku sali VBHP w Gdańsku po zakończeniu prac związanych z jego remonem opraz opisano zakres podjętych prac naprawczych

  • Book Review
    • Edward Szczerbicki
    2021 Intelligent Decision Technologies-Netherlands

    Acting over the last three decades as an Editor and Associate Editor for a number of international journals in the general area of cybernetics and AI, as well as a Chair and Co-Chair of numerous conferences in this field, I have had the exciting opportunity to closely witness and to be actively engaged in the stimulating research area of machine learning and its important augmentation with deep learning techniques and technologies. From this extensive personal perspective of an active researcher, I consider the book “Machine Learning Paradigms: Advances in Deep Learning-based Technological Applications” a very important and truly outstanding contribution into the enhancement of our understanding of how deep learning can be applied in real life centred technologies and techniques within a number of important and truly diverse domains. These domains include medical, geospatial, social, economic, and food processing just to mention a few that are covered in this significant book. Its 16 chapters are all well presented, coherent, and well written. The presented applications are innovative and supported by scientifically rigorous research. I find it remarkable that the Editors were able to complete such a comprehensive compendium on deep learning challenges, advances and applications. With no hesitation, I recommend it as a “must read” reference for researchers, practitioners, and higher research degrees students who want to experience truly exciting deep dive into a full-fledged deep learning. Two renowned global class experts in the field edit the book, which for me is always the best indicator of the importance and quality of the content. I would like to finish this brief review expanding a bit further on my personal viewpoint regarding the book. For any active researcher like myself, the most important advantage of the book is the fact that it leaves its reader with a heightened ability to think – in different ways – about developing, evaluating, and implementing deep learning-based techniques and technologies in real life environments.

  • Boron-Doped Diamond/GaN Heterojunction—The Influence of the Low-Temperature Deposition
    • Michał Sobaszek
    • Marcin Gnyba
    • Sławomir Kulesza
    • Mirosław Bramowicz
    • Tomasz Klimczuk
    • Robert Bogdanowicz
    2021 Full text Materials

    We report a method of growing a boron-doped diamond film by plasma-assisted chemical vapour deposition utilizing a pre-treatment of GaN substrate to give a high density of nucleation. CVD diamond was deposited on GaN substrate grown epitaxially via the molecular-beam epitaxy process. To obtain a continuous diamond film with the presence of well-developed grains, the GaN substrates are exposed to hydrogen plasma prior to deposition. The diamond/GaN heterojunction was deposited in methane ratio, chamber pressure, temperature, and microwave power at 1%, 50 Torr, 500 C, and 1100 W, respectively. Two samples with different doping were prepared 2000 ppm and 7000 [B/C] in the gas phase. SEM and AFM analyses revealed the presence of well-developed grains with an average size of 100 nm. The epitaxial GaN substrate-induced preferential formation of (111)-facetted diamond was revealed by AFM and XRD. After the deposition process, the signal of the GaN substrate is still visible in Raman spectroscopy (showing three main GaN bands located at 565, 640 and 735 cm1) as well as in typical XRD patterns. Analysis of the current–voltage characteristics as a function of temperature yielded activation energy equal to 93.8 meV.

  • Borrelia burgdorferi BmpA-BBK32 and BmpA-BBA64: New Recombinant Chimeric Proteins with Potential Diagnostic Value
    • Weronika Grąźlewska
    • Bartłomiej Ferra
    • Lucyna Holec-Gąsior
    2021 Full text Pathogens

    Currently, the diagnosis of Lyme disease is based mostly on two-tiered serologic testing. In the new generation of immunoenzymatic assays, antigens comprise whole-cell lysates of members of the Borrelia burgdorferi sensu lato (s.l.) species complex, with the addition of selected recombinant proteins. Due to the high diversity of members of the B. burgdorferi s.l. genospecies and the low degree of conservation among the amino acid sequences of their proteins, serodiagnostic methods currently in use are not sufficient for the correct diagnosis of borreliosis. Two divalent chimeric proteins (BmpA-BBK32 and BmpA-BBA64) were expressed in Escherichia coli. Following purification by one-step metal-affinity chromatography, preparations were obtained containing milligram levels of chimeric protein exhibiting electrophoretic purity in excess of 98%. Reactivity of the new chimeric proteins with specific human IgG antibodies was preliminarily determined by Western blot. For this purpose, 20 negative sera and 20 positive sera was used. The new chimeric proteins were highly reactive with IgG antibodies contained in the serum of patients suffering from borreliosis. Moreover, no immunoreactivity of chimeric proteins was observed with antibodies in the sera of healthy people. These promising results suggest that new chimeric proteins have the potential to discriminate between positive and negative sera.

  • Bortezomib induces methylation changes in neuroblastoma cells that appear to play a significant role in resistance development to this compound
    • Karolina Łuczkowska
    • Katarzyna Ewa Sokołowska
    • Olga Taryma-Leśniak
    • Krzysztof Pastuszak
    • Anna Supernat
    • Jonas Bybjerg-Grauholm
    • Lise Lotte Hansen
    • Edyta Paczkowska
    • Tomasz K. Wojdacz
    • Bogusław Machaliński
    2021 Full text Scientific Reports

    The anticancer activity of bortezomib (BTZ) has been increasingly studied in a number of indications and promising results for the use of this treatment have been shown in neuroblastoma. As BTZ treatment is usually administered in cycles, the development of resistance and side effects in patients undergoing therapy with BTZ remains a major challenge for the clinical usage of this compound. Common resistance development also means that certain cells are able to survive BTZ treatment and bypass molecular mechanisms that render BTZ anticancer activity. We studied the methylome of neuroblastoma cells that survived BTZ treatment. Our results indicate that BTZ induces pronounced genome wide methylation changes in cells which recovered from the treatment. Functional analyses of identified methylation changes demonstrated they were involved in key cancer pathology pathways. These changes may allow the cells to bypass the primary anticancer activity of BTZ and develop a treatment resistant and proliferative phenotype. To study whether cells surviving BTZ treatment acquire a proliferative phenotype, we repeatedly treated cells which recovered from the first round of BTZ treatment. The repetitive treatment led to induction of the extraordinary proliferative potential of the cells, that increased with subsequent treatments. As we did not observe similar effects in cells that survived treatment with lenalidomide, and non‑treated cells cultured under the same experimental conditions, this phenomenon seems to be BTZ specific. Overall, our results indicate that methylation changes may play major role in the development of BTZ resistance.

  • Bounds on isolated scattering number
    • Marcin Jurkiewicz
    2021

    The isolated scattering number is a parameter that measures the vulnerability of networks. This measure is bounded by formulas de- pending on the independence number. We present new bounds on the isolated scattering number that can be calculated in polynomial time.

  • Bounds on isolated scattering number
    • Marcin Jurkiewicz
    2021 ANZIAM JOURNAL

    The isolated scattering number is a parameter that measures the vulnerability of networks. This measure is bounded by formulas de- pending on the independence number. We present new bounds on the isolated scattering number that can be calculated in polynomial time.

  • Brief Literature Review and Classification System of Reliability Methods for Evaluating the Stability of Earth Slopes
    • Jarosław Przewłócki
    2021 Full text Sustainability

    The issue of slope stability is one of the most important and yet most difficult geotechnical problems. Assessing slope stability is particularly difficult because of the many uncertainties involved in the process. To take these uncertainties into account, probabilistic methods are used, and the reliability approach is adopted. There are many methods for reliability assessment of earth slope stability. However, there is no system that would organize all of these methods in an unambiguous way. In fact, these methods can be classified in different ways: by assignment to a deterministic classification of methods, by description of uncertainties of soil parameters, by level of reliability according to the theory of reliability, etc. The huge number of articles summarizing the research in this field, but in various “disordered” directions, certainly do not facilitate the understanding or ultimately the practical application of the reliability approach by the engineer. The paper proposes a universal classification system of reliability methods for evaluating the stability of earth slopes. This proposal is preceded by a brief literature review of both historical background and contemporary research on reliability analysis of earth slope stability.

  • Budowanie strategii edukacyjnej uczelni z uwzględnieniem wykorzystania e-technologii – wnioski z analizy doświadczeń uczelni technicznej
    • Anita Dąbrowicz-Tlałka
    • Magdalena Musielak
    2021 Full text Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

    Artykuł zawiera wnioski z podsumowania działań koncepcyjnych i organizacyjnych jakie zostały przeprowadzone w toku rozbudowy uczelnianej platformy edukacyjnej i jej integracji z systemami uczelni. Autorki podjęły starania, aby na podstawie analizowanego przypadku uczelni technicznej, przedstawić rekomendacje związane z tworzeniem edukacyjnej strategii uczelni w zakresie zdalnej edukacji. W artykule przedstawiono dane z ankiet oraz dane dotyczące systemów edukacyjnych Politechniki Gdańskiej, które uzyskano w okresie zawieszenia kształcenia na uczelniach.

  • Burnout Investigation of Small Diameter Tubes Immersed in Nanofluids
    • Janusz Cieśliński
    • Katarzyna Ronewicz
    2021 Full text ENERGIES

    This paper deals with research into pool boiling critical heat flux (CHF) of water–Al2O3, water–TiO2 and water–Cu nanofluids on horizontal stainless steel tubes. The experiments were conducted under atmospheric pressure. Nanoparticles were tested at concentrations of 0.001%, 0.01%, 0.1% and 1% by weight. Ultrasonic vibration was used in order to stabilize the dispersion of the nanoparticles. Although dispersants were not used to stabilize the suspension, the solutions tested showed satisfactory stability. Experimental measurements were performed with stainless steel tubes of three outside diameters: 1.6, 3 and 5 mm. Enhancement of CHF was observed to be independent of the concentration and material of the nanoparticles and tube diameter, with simultaneous heat transfer degradation. Built up during the boiling process, nanolayers improve substantially the heating surface wettability. A correlation is suggested for the CHF prediction during pool boiling of nanofluids.

  • Business continuity management framework for Industry 4.0 companies regarding dependability and security of the ICT and ICS/SCADA system
    • Kazimierz Kosmowski
    2021 Full text

    This chapter addresses a business continuity management (BCM) framework for the Industry 4.0 companies including the organizational and technical solutions, regarding the dependability and security of the information and telecommunication technology (ICT), and the industrial control system (ICS) / supervisory control and data acquisition (SCADA) system. These technologies and systems play nowadays important roles in modern advanced manufacturing systems and process plants due to their openness to external systems and networks using various communication channels. It gives on the one hand, some advantages in effective realization of technological and business processes, logistics and distribution of goods, but, on the other hand, makes the company assets and resources potentially vulnerable to some threats with relevant risks. The chapter outlines some ideas related to designing a business continuity management system (BCMS) based on defined processes and procedures. Such system includes planning of changes in organization / industrial company, nonconformity issues, and planning corrective actions. In a final part of this chapter the leadership importance, and staff awareness and responsibility are emphasized to create a robust and healthy corporate culture based on accepted values, properly spread among the employees. It is beneficial for shaping good organizational culture, and then safety and security culture. The BCM approach outlined in this chapter distinguishes both preventive and recovery activities regarding suggestions in selected international standards and domain publications.

  • Buzz-based honeybee colony fingerprint
    • Tymoteusz Cejrowski
    • Julian Szymański
    2021 Full text COMPUTERS AND ELECTRONICS IN AGRICULTURE

    Non-intrusive remote monitoring has its applications in a variety of areas. For industrial surveillance case, devices are capable of detecting anomalies that may threaten machine operation. Similarly, agricultural monitoring devices are used to supervise livestock or provide higher yields. Modern IoT devices are often coupled with Machine Learning models, which provide valuable insights into device operation. However, the data preparation step for ML models has to be addressed differently for industrial and agriculture cases. Animals are characterized by their circadian rhythms and seasonal dependence, which can bias the accuracy of classifiers. In the presented work, a Design-of-Experiment (DoA) approach for extracting valuable bee colony audio data is described. With the presented methods, it is possible to precisely define the most distinctive bee hours where unique colony sounds are emitted. The first step of the data filtering process is based on identifying the ambient temperatures that are conducive to its operation. The second step provides the unique hours specification based on the hives’ characteristics comparison where dissimilar time periods are being marked. For this comparison, the most noticeable difference between the colonies is calculated with MSE integral and thus the trend’s joint component is removed. A new concept of a bees’ fingerprint was introduced for the identification of the particular bee colony.

  • Bypass kolejowy dla wiaduktu łukowego i kratownicowego w ciągu modernizowanej linii kolejowej E59 na odcinku Wronki – Dobiegniew
    • Agnieszka Makowska
    • Cezary Najda
    • Anna Banaś
    2021 Mosty

    W artykule przedstawiono realizacje bypassu kolejowego, zlokalizowanego nieopodal miejscowości Krzyż Wielkopolski w ciągu linii kolejowej E59 na skrzyżowaniu z linią kolejową 203. Wariantowa analiza kilku zaproponowanych rozwiązań wykazała, ze wykonstruowanie bypassu na czas prowadzenia prac modernizacyjnych pozwoli na utrzymanie ciągłości ruchu kolejowego, nie stworzy nadmiernych problemów podróżnym, a jednocześnie pozwoli na obniżenie kosztów inwestycji w stosunku do wdrożenia komunikacji zastępczej.

  • By-Products from Food Industry as a Promising Alternative for the Conventional Fillers for Wood–Polymer Composites
    • Aleksander Hejna
    • Jerzy Korol
    • Paulina Kosmela
    • Anton Kuzmin
    • Adam Piasecki
    • Arkadiusz Kulawik
    • Błażej Chmielnicki
    2021 Full text Polymers

    The present paper describes the application of two types of food-industry by-products, brewers’ spent grain (BSG), and coffee silverskin (ŁK) as promising alternatives for the conventional beech wood flour (WF) for wood–polymer composites. The main goal was to investigate the impact of partial and complete WF substitution by BSG and ŁK on the processing, structure, physicochemical, mechanical, and thermal properties of resulting composites. Such modifications enabled significant enhancement of the melt flowability, which could noticeably increase the processing throughput. Replacement of WF with BSG and ŁK improved the ductility of composites, which affected their strength however. Such an effect was attributed to the differences in chemical composition of fillers, particularly the presence of proteins and lipids, which acted as plasticizers. Composites containing food-industry by-products were also characterized by the lower thermal stability compared to conventional WF. Nevertheless, the onset of decomposition exceeding 215 ◦C guarantees a safe processing window for polyethylene-based materials.

  • Cable-stayed bridges. Basic static schemes
    • Krzysztof Żółtowski
    2021 Full text Archives of Civil Engineering

    The paper presents an overview of shaping of cable-stayed bridges. Historical background, basic static sketches and overview of selected bridges are included. Selected natural solutions and interesting unrealized projects were presented. Basic ideas and most important principals are discussed. The examples and sketches were given an author's comment. Static diagrams of two pylon structures with three variants of the arrangement of cables are presented. The details important for the structure were discussed and the consequences of choosing the variant were indicated. Mono-pylon structures in asymmetric and symmetrical arrangements are shown. the solutions are discussed and the details important for the structure are indicated. An overview of multi-pylon structures is also presented, paying attention to important details. All the discussed static diagrams were enriched with realized examples. The advantages and disadvantages of individual structural solutions are presented. The main ideas allowing to achieve the goal in the implementation of non-standard suspended structures were also indicated.

  • Calibration-Free Single-Anchor Indoor Localization Using an ESPAR Antenna
    • Mateusz Groth
    • Krzysztof Nyka
    • Łukasz Kulas
    2021 Full text SENSORS

    In this paper, we present a novel, low-cost approach to indoor localization that is capable of performing localization processes in real indoor environments and does not require calibration or recalibration procedures. To this end, we propose a single-anchor architecture and design based on an electronically steerable parasitic array radiator (ESPAR) antenna and Nordic Semiconductor nRF52840 utilizing Bluetooth Low Energy (BLE) protocol. The proposed algorithm relies on received signal strength (RSS) values measured by the receiver equipped with the ESPAR antenna for every considered antenna radiation pattern. The calibration-free concept is achieved by using inexpensive BLE nodes installed in known positions on the walls of the test room and acting as reference nodes for the positioning algorithm. Measurements performed in the indoor environment show that the proposed approach can successfully provide positioning results better than those previously reported for single-anchor ESPAR antenna localization systems employing the classical fingerprinting method and relying on time-consuming calibration procedures.

  • Can bottom sediments be a prospective fertilizing material? A chemical composition analysis for potential reuse in agriculture.
    • Karolina Matej-Łukowicz
    • Ewa Wojciechowska
    • Joanna Strycharz
    • Marta Szubska
    • Karol Kuliński
    • Jacek Bełdowski
    • Aleksandra Winogradow
    2021 Full text Materials

    Every year huge amounts of bottom sediments are extracted worldwide, which need to be dis-posed. The recycling of bottom sediments for soil fertilization is in line with the long-promoted circular economy policy and enables the use of micro and macronutrients accumulated in sedi-ments for soil fertilization. When considering potential agricultural reuse of the dredge sediments, the first necessary step should be to analyze whether the heavy metal content meets the obligatory criteria. Then, the contents of valuable elements required for plant growth and their ratios should be assessed. In this study, the content of nitrogen, organic carbon, phosphorus and potassium was tested and iron, sulfur, calcium and magnesium were also analysed along vertical profiles of sed-iments extracted from 4 urban retention tanks in Gdańsk (Poland). The sediments were indicated to have a low content of nutrients (Ntot 0.01-0.52%, Corg 0.1-8.4%, P₂O₅ 0.00-0.65%, K 0.0-1.0%) while being quite rich in Fe and S (0.2-3.3%, 0.0-2.5% respectively). The C/N ratio changed in the range of 17.4-28.4, which proved good nitrogen availability for plants. The mean values of the Fe/P ratio were above 2.0, which confirms that phosphorus in the sediments would be available to the plants in the form of iron phosphate. To sum up, the bottom sediments from municipal reten-tion reservoirs are not a perfect material for soil fertilization, but they are a free waste material which, when enriched with little cost, can become a good fertilizer. Future research should focus on cultivation experiments with the use of sediments enriched with N, P, Corg.

  • Can the Pandemic Be a Catalyst of Spatial Changes Leading Towards the Smart City?
    • Barbara Zgórska
    • Dorota Kamrowska-Załuska
    • Piotr Lorens
    2021 Full text Urban Planning

    The worldwide spread of Covid‐19 infections has had a pervasive influence on cities and the lives of their residents. The current crisis has highlighted many urban problems, including those related to the functionality of urban structures, which directly affect the quality of life. Concurrently, the notion of “smart cities” is becoming a dominant trend in the discourse on urban development. At the intersection of these two phenomena, questions about the effects of Covid‐19 on the future of cities arise. These are concerned with the possible roles of the pandemic in the process of urban regeneration and the development of smart solutions. The article aims to create a conceptual framework that will allow researchers to assess the influence of Covid‐19‐related changes on urban structures and their functionality in the following areas: city structure, connectivity and mobility, public spaces, access to green areas, and digital transformation. In the empirical part of the article, the influence of pandemic‐caused changes on the development of various aspects of smart cities is discussed. The article concludes with an analysis of the effects the pandemic might have on digital urban regeneration

  • Can Web Search Queries Predict Prices Change on the Real Estate Market?
    • Nina Rizun
    • Anna Baj-Rogowska
    2021 Full text IEEE Access

    This study aims to explore whether the intensity of internet searches, according to the Google Trends search volume index (SVI), is a predictor of changes in real estate prices. The motivation of this study is the possibility to extend the understanding of the extra predictive power of Google search engine query volume of future housing price change (shift direction) by (i) the introduction of a research approach that combines the advantages of the complementary use of cross-correlation analysis and machine learning classification algorithms; (ii) applying the multi-class HPI values classifier which allows predicting the housing price increase, decrease or relative stability; (iii) exploiting the SVI that relates to interests in both ‘real estate’ and ‘credit to buy real estate’; (iv) evaluation of the introduced approach in the context of the Polish real estate market. The main theoretical contribution of our work is a confirmation that the freely available information regarding Google user searches can provide an in-depth insight into enriching the generally accepted statistics on supply and demand in the real estate market. From the practical perspective, this research confirms that SVI can be associated as a sole determinant to anticipate the housing price change with time-lag sufficient for making decisions regarding the purchase (sale) of individual property or the real estate market control. Such findings can be also helpful for researchers who intend to use Google Trends data as an extra variable from demand side to improve the prediction accuracy if it is included in the model which is based on the existing housing prices determinants.

  • CaO-based high temperature CO2 sorbents – Literature review
    • Donata Konopacka-Łyskawa
    • Natalia Czaplicka
    • Andrzej Szefer
    2021 Full text Chemical and Process Engineering : New Frontiers

    The use of CaO-based adsorbents has a high potential to capture CO2 from various systems due to its high reactivity with CO2, high capacity, and low cost of naturally derived CaO. The application of CaO-based sorbents to remove carbon dioxide is based on a reversible reaction between CaO and CO2. However, multiple carbonation/calcination cycles lead to a rapid reduction in the sorption capacity of natural CaO, and therefore efforts are made to reduce this disadvantage by doping, regenerating, or producing synthetic CaO with stable sorption properties. In this review, the synthesis methods used to obtain CaO-based sorbents were collected, and the latest research on improving their sorption properties was presented. The most commonly used models to describe the CO2 sorption kinetics on CaO-based sorbents were also introduced. The methods of sorbent regeneration and their effectiveness were summarized. In the last part of this review, the current state of advancement of work on the larger scale, possible problems, and opportunities during scale-up of the calcium looping process were presented. Concluding (i) the presented methods of adsorbent synthesis allow for the production of doped CaO adsorbents on a laboratory scale, characterized by high CO2 capture efficiency and good cyclic stability, (ii) the most commonly used in practice models describing CO2 chemisorption are empirical models and the shrinking core model, (iii) the use of sorbent regeneration allows for a significant improvement in sorption capacity, (iv) the scale-up of both the production of new CaO adsorbents and the CO2 capture technology with their use requires further development.

  • Carbon nanoarchitectures as high-performance electrodes for the electrochemical oxidation of landfill leachate
    • Mattia Pierpaoli
    • Paweł Jakóbczyk
    • Mirosław Sawczak
    • Aneta Łuczkiewicz
    • Sylwia Fudala-Książek
    • Robert Bogdanowicz
    2021 Full text JOURNAL OF HAZARDOUS MATERIALS

    Nanomaterials and assemblies of the aforementioned into complex architectures constitute an opportunity to design efficient and selective solutions to wide spread and emerging environmental issues. The limited disposal of organic matter in modern landfills generates extremely concentrated leachates characterised by high concentrations of refractory compounds. Conventional biochemical treatment methods are unsuitable, while advanced treatment, such coagulation, reverse osmosis and ultrafiltration can be very costly and generate additional waste. Electrochemical oxidation is an established technique to efficiently mineralise a plethora of recalcitrant pollutants, however the selectivity and efficiency of the process are strongly related to the anode material. For this reason, a nanoarchitectured carbon material has been designed and synthesised to improve the capability of the anode towards the adsorption and decomposition of pollutants. Instead of simple nanostructures, intelligently engineered nanomaterials can come in handy for more efficient advanced treatment techniques. In this study, a carbon nanoarchitecture comprising boron-doped vertically aligned graphene walls (BCNWs) were grown on a boron-doped diamond (BDD) interfacial layer. The results show how the peculiar maze-like morphology and the concurrence of different carbon hybridisations resulted in a higher current exchange density. The BDD performed better for the removal of NH4+ while the BCNW-only sample exhibited a faster deactivation. The BDD/BCNW nanoarchitecture resulted in an enhanced COD removal and a NH4+ removal similar to that of BDD, without the intermediate production of NO2− and NO3−.

  • Cascade Object Detection and Remote Sensing Object Detection Method Based on Trainable Activation Function
    • S. N. Shivappriya
    • M. Jasmine Pemeena Priyadarsini
    • Andrzej Stateczny
    • C. Puttamadappa
    • B. D. Parameshachari
    2021 Full text Remote Sensing

    Object detection is an important process in surveillance system to locate objects and it is considered as major application in computer vision. The Convolution Neural Network (CNN) based models have been developed by many researchers for object detection to achieve higher performance. However, existing models have some limitations such as overfitting problem and lower efficiency in small object detection. Object detection in remote sensing hasthe limitations of low efficiency in detecting small object and the existing methods have poor localization. Cascade Object Detection methods have been applied to increase the learning process of the detection model. In this research, the Additive Activation Function (AAF) is applied in a Faster Region based CNN (RCNN) for object detection. The proposed AAF-Faster RCNN method has the advantage of better convergence and clear bounding variance. The Fourier Series and Linear Combination of activation function are used to update the loss function. The Microsoft (MS) COCO datasets and Pascal VOC 2007/2012 are used to evaluate the performance of the AAF-Faster RCNN model. The proposed AAF-Faster RCNN is also analyzed for small object detection in the benchmark dataset. The analysis shows that the proposed AAF-Faster RCNN model has higher efficiency than state-of-art Pay Attention to Them (PAT) model in object detection. To evaluate the performance of AAF-Faster RCNN method of object detection in remote sensing, the NWPU VHR-10 remote sensing data set is used to test the proposed method. The AAF-Faster RCNN model has mean Average Precision (mAP) of 83.1% and existing PAT-SSD512 method has the 81.7%mAP in Pascal VOC 2007 dataset.

  • Case study of water vapour transmission properties of EPDM façade membranes
    • Andrzej Ambroziak
    • Sławomir Dobrowolski
    2021 Full text Archives of Civil Engineering

    This research aimed to investigate the water vapour transmission properties of chosen EPDM membranes applied in façade and window systems under laboratory tests. The applied procedure included in national and international standards utilized for the laboratory tests of water vapour transmission properties of EPDM membrane is described. Two main types (outside and inside types) of EPDM membranes are laboratory tested. The authors indicated that the EPDM membranes should differ in surface factures. Nevertheless, some manufacturers mark EPDM membranes on each roll (on the package only) without different permanent denotations on the EPDM membranes surfaces. This form of denotations can cause using problems-using the wrong types of the EPDM aprons in building partitions, because when the package is removed there is impossible to visually identify the type of EPDM membrane (outside or inside type) from the texture of the membrane surface. The experimental results of laboratory tests indicated using the wrong type of EPDM membrane in the inside aprons in building partitions in the investigated façade window system. The designed proportion of the sd values (the resistance to movement of water vapour) of inside and outside EPDM façade membranes should be designed equally to about 3.0 (recommended value 4) to provide proper diffusion properties of partitions around windows in façade systems. The paper can provide scientists, engineers, and designers an experimental basis in the field of the EPDM membranes water vapour transmission properties applied to façades and windows systems.

  • Cassirer E. Język i mit. Przyczynek do zagadnienia imion bogów.Przekład, wstęp i opracowanie: Przemysław Parszutowicz.. Wydaw. Marek Drzewiecki,2021
    • Przemysław Parszutowicz
    2021

    Rozprawa Cassirera pochodzi z najważniejszego bodaj okresu jego twórczości – okresu współpracy z Biblioteką Warburga – i mimo niewielkich rozmiarów jest w dużej mierze reprezentatywna, tak gdy idzie o wykorzystywaną przez niego metodę, jak i o główny obszar jego zainteresowań badawczych. Stanowi bezpośrednie nawiązanie do rozprawy Hermanna Usenera Götternamen. Versuch einer Lehre von der religiösen Begriffsbildung. Pod względem swojej treści książka przedstawia silną korelację języka i mitu, słowa i magii, biorąc za punkt wyjścia twierdzenie o zasadniczej zgodności istoty bóstwa z jego imieniem. Opisuje przykłady sprawczej siły słowa w świecie opanowanym przez myślenie mityczne i przez to wskazuje na zasady i swoistą „logikę” mitu. Język przedstawia tutaj to, co myślenie mityczne bezpośrednio wyraża: odzwierciedlenie całości w każdym szczególe, przyczynowość opartą na celowym działaniu jakiegoś podmiotu, a zatem uduchowienie i personifikację przyrody, oparcie na zmysłowym, bezpośrednim oglądzie, na bezpośredniej zmysłowej obecności.

  • CEL FUNKCJONOWANIA, ZADANIA I OBSZARY BADAWCZE CENTRUM MORSKIEJ ENERGETYKI WIATROWEJ POLITECHNIKI GDAŃSKIEJ
    • Zbigniew Korczewski
    2021 Full text Journal of Polish CIMEEAC

    W artykule przybliżono wybrane aspekty funkcjonowania Centrum Morskiej Energetyki Wiatrowej w Politechnice Gdańskiej. Scharakteryzowano główne zadania Centrum oraz wstępnie zdefiniowane obszary badawcze, w których specjalizują się naukowcy reprezentujący niemal wszystkie wydziały akademickie Uczelni (oprócz Wydziału Architektury). Przedstawiono kierunki działania Centrum w perspektywie kilku najbliższych lat, w wyniku których nastąpi weryfikacja i konieczne doprecyzowanie obszarów badawczych, zgodnie z oczekiwaniami inwestorów morskich farm wiatrowych budowanych w polskiej wyłącznie strefie ekonomicznej Morza Bałtyckiego.

  • Cellulosic bionanocomposites based on acrylonitrile butadiene rubber and Cuscuta reflexa: adjusting structure-properties balance for higher performance
    • Midhun Dominic C.D.
    • Rani Joseph
    • P.M. Sabura Begum
    • Athira S Kumar
    • P. A. Jeemol
    • Thomasukutty Jose
    • Dileep Padmanabhan
    • Krzysztof Formela
    • Suchart Siengchin
    • Jyotishkumar Parameswaranpillai
    • Mohammad Saeb
    2021 CELLULOSE

    Design and manufacture of cellulosic nanocomposites with acceptable performance is in the period of a transition from fantasy to reality. Typically, cellulosic nanofillers reveal poor compatibility with polymer matrices. Thus, adjusting the balance between structure and properties of cellulosic bionanocomposites by careful selection of parent ingredients is the first priority. Herein, we incorporated Cuscuta reflexa derived cellulose nanofibers (CNFs) into acrylonitrile-butadiene rubber (NBR) for high-performance elastomeric applications. Tensile and tear strength of NBR improved by ~ 125 and ~ 105 %, respectively at a very low loading of 4 phr CNFs, as a result of interfacial bonding, as evidenced by fractographic analysis. In parallel, the temperature at which maximum degradation occurs (Tmax) of NBR rose by 14 °C. The swelling index and molar uptake of toluene were also lowered. The Wolff-activity coefficient, hardness, abrasion resistance, and cross-link density were all improved correspondingly. The positive shift in glass transition temperature and the fall in the loss tangent peak height for bionanocomposites proved the effective immobilization of NBR chains by well-dispersed CNFs. The hydrogen bonding interaction between –OH groups of CNFs and –CN groups of NBR might be responsible for the superior performance of NBR/CNF composites, which is confirmed by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD).

  • Cement kiln dust
    • Hakim S. Abdelgader
    • Mugahed Amran
    • Marzena Kurpińska
    • Mohammad Mosaberpanah
    • Gunasekaran Murali
    • Roman Fediuk
    2021

    The volume of cement production in the world has remained at the level of approxi mately 4.1 billion tons/year. The cement production process is energy intensive and is the world’s leading emitter of carbon dioxide. Therefore, the main activities cement plants are aimed at introducing technologies changes in production of clinkier.The construction industry is responsible for the majority of CO2 emissions to the atmosphere: the industry emits 30% of total CO2, building emits 28%, transportation is responsible for 22% of CO2, the production of building materials causes 11% of CO2 emissions, including the cement industry is responsible for around 7% of emissions CO2. Other industries are responsible for around 9% of CO2 emissions to the atmosphere. The process of burning raw materials for the production of clinker is the most important stage of the entire cement production process. Cement kiln dust (CKD) is waste generated during the production of clinker. The dust collected in the dust collectors is partly reused in the production process and some is stored. The storage method is not preferred due to its operations negative en vironmental impact. If the dust contains alkalis, chlorides, sulphates, or heavy metals, they cannot be recycled. Generally cement plants strive to reduce the formation of dust. About 1.5 tons of raw materials are used to produce 1 ton of clinker. After the extraction, grinding, and homogenization of raw materials, the process of calcination of calcium carbonate takes place. The source of calcium carbonate is naturally occurring limestone deposits, namely limestone, marl, or chalk. Then, to obtain clinker, calcium oxide is sintered with silica, aluminum oxide, and iron oxide at a temperature of 1450°C. Most often, clinker is fired using the dry or wet method in a long rotary kiln. After firing, the clinker is ground together with the binding regulator - gypsum and additives. To generate the heat needed to burn the clinker, fossil fuels such as petcoke, hard coal, lignite, and fuel oil or natural gas are used. Due to proecological activities, secondary solid fuels are used as alternative fuels as substitutes for fossil fuels. The amount of thermal energy obtained from their combustion currently accounts for about 85% of the total amount of thermal energy used in the clinker burning process. These changes lead to effective energy management through the efficient use of natural and alternative fuels.

  • Cerclage cable augmentation does not increase stability of the fixation of intertrochanteric fractures. A biomechanical study
    • Marcin Ceynowa
    • Krzysztof Żerdzicki
    • Paweł Kłosowski
    • Rafał Pankowski
    • Marek Rocławski
    • Tomasz Mazurek
    2021 Orthopaedics & Traumatology-Surgery & Research

    Background: Intertrochanteric fractures with a posteromedial intermediate fragment are unstable because of the loss of medial support. Additional fixation with a cerclage is used in subtrochanteric fractures, but not in intertrochanteric fractures. The aim of this biomechanical study is to evaluate whether cerclage fixation improves stability of intertrochanteric fractures. Hypothesis: Our hypothesis is that the cerclage fixation of the intermediate fragment increases fixation stability of intertrochanteric fractures.Materials and methods: Synthetic femora with intertrochanteric fractures (AO 31.A1.3) with a posteromedial fragment were fixed with a long gamma nail. The intermediate fragment was fixed with a cerclage cable. Four groups were compared: 1: no cable fixation; 2: anatomic reduction and cable fixation; 3:anatomic reduction and fixation of a fragment where its proximal part was removed simulating comminution; 4: non-anatomic reduction and cable fixation. The specimens were loaded axially in a testing machine. The preload was 100 N, followed by ten conditioning cycles from 100 N to 500 N. The test phase consisted of the cyclic loading between 100 N and the maximum force that increased at a rate of 50 N at each cycle until failure. The stiffness was calculated from the load/displacement curve of the last three conditioning cycles.Results: There were no statistically significant differences between force to failure (group 1: 681 N; group2: 846 N; group 3: 699 N; group 4: 806 N; ANOVA p = 0.23) and stiffness (group 1: 769 N/mm; group2: 819 N/mm; group 3: 815 N/mm; group 4: 810 N/mm; ANOVA p = 0.84) between groups. There were significant differences in the widening of the lag screw canal (group 1: 2.16 mm; group 2: 4.5 mm; group3: 3 mm; group 4: 2.5 mm; ANOVA p = 0.017). In individual comparison, the differences were significant only between the anatomical reduction group and the non-anatomical reduction (p = 0.04) and the no cable group (p = 0.02).Discussion: There is a controversy in clinical literature whether cable fixation improves treatment outcome of proximal femoral fractures. This study suggests that medial wall reconstruction with a cerclage cable does not improve axial stability of the fixation. Level of evidence: Not applicable; a biomechanical study.

  • CFD Simulations and Tests of a Prototype Flow Control Valve
    • Marta Zaleska-Patrosz
    • Piotr Patrosz
    • Paweł Śliwiński
    2021 Full text

    In this paper a prototype of a flow control valve is described and numerically simulated. The flow control valve is used in hydraulic systems to maintain constant fluid flow despite changing loads of a receiver. The standard construction of this type of valves is modified mainly by eliminating the spring. The prototype consists the hydrostatically unloaded throttle valve and pressure ratio valve substituting pressure difference valve. The article concentrates on numerical simulation conducted for different positions of pressure ratio valve’s spool and various throttle valve settings. Additionally the rotation of the spool is included in simulation and its influence on valve’s characteristics is evaluated. The article also describes the methodology of determining flow characteristics of control valve. Results from numerical simulation are compared to results of experimental research.

  • CFFT columns in road through railroad crossings
    • Eligiusz Mieloszyk
    • Anita Milewska
    • Marcin Abramski
    2021

    There were 12801 road through railroad one-level crossings in Poland in 2018. 215 accidents happened at them in 2018. In order to increase safety in rail and road traffic two-level crossings should be used. They are definitely safer and make the traffic more smooth. In the design and construction of two-level intersections of railway and road or path columns of circular cross-section are often used. They can be successfully replaced by CFFT columns (Concrete-Filled (Fibre-Reinforced Polymer) Tube). The advantage of CFFT columns is the possibility of their widespread use. As the research of these columns shows, including those conducted at the Gdansk University of Technology, they can carry significant compressive loads by their relatively small cross-section. They are resistant to corrosion and protect against corrosion concrete and its reinforcement (if used). In addition, it is worth adding that the electrical resistance of FRP composite is greater than 1GΩ, which is particularly important in the case of electrified railway lines or tram lines.

  • Chain Action - How Do Countries Add Value Through Digital Government?
    • Jaromir Durkiewicz
    • Tomasz Janowski
    2021 Full text

    This study examineshow countries develop and benefit from Digital Government(DG).The literature proposes various conceptualizations of the value-adding logic of DG, but the benchmarking practice is not respondingto such proposals.For instance, the United Nations’E-Government Surveycombines the readiness and uptake indicatorsand failsto cover any impactindicators;thus,its diagnostic valueis limited. To overcome this limitation, weintroduce a new assessment schemebased on the DG value chain conceptand pursue the question: how do the world countries add value in this chain?Reassembling the UN’s e-Government Survey indicatorsand the World Bank’s Worldwide Governance Indicators,we examine how the 191 UN Member States converted their readiness into uptakeanduptake into impactover the 2014-2018 period. The results rank the countries concerning their performance alongthe DG value chain, identify hotspots, and calculatethe value chain performance of regional and economic groups.

  • Challenges and opportunities related to the use of sewage sludge ash in cement-based building materials – A review
    • Lesław Świerczek
    • Bartłomiej Cieślik
    • Piotr Konieczka
    2021 Full text JOURNAL OF CLEANER PRODUCTION

    Due to the increasingly demanding legal regulations, regarding both sewage sludge (SS) and solid residues obtained during its thermal utilization processes, new solutions to limit their negative impact on the environment are sought. One approach that eliminates the risk of sewage sludge ash (SSA) is its use in cement building materials. The article contains a detailed literature review regarding the use of SSA in mortars and concretes, where it is defined as the addition or substitute of the main binder. The issues of the impact of SSA quality (CaO content, the share of pozzolanic oxides, their ratio) on cement products are discussed in details. In addition to the description of the mechanical properties of building materials, the SSA impact on parameters such as workability, shrinkage of products and setting time is also described. It can be stated that using SSA in building industry is one of the most ecological approaches of SSA managing. Due to the toxic nature of SSA, data on the leaching of heavy metals from hardened mortar or concrete samples are presented to emphasize the contaminants immobilization effectiveness by cement products. Based on the analysis of the data presented in the article, solutions that can reduce the negative consequences of including SSA in building materials have been identified. However, due to the significant differences in SS thermal utilization technologic and SS characteristics, every SSA should be thoroughly characterized before implementing the most suitable stabilization/solidification methods