Repozytorium publikacji - Politechnika Gdańska

Ustawienia strony

english
Repozytorium publikacji
Politechniki Gdańskiej

Pokaż publikacje z roku

Ostatnie pozycje

  • Bankruptcy Law Severity for Debtors: Comparative Analysis Among Selected Countries
    • Sylwia Morawska
    • Błażej Prusak
    • Przemysław Banasik
    • Katarzyna Pustułka
    • Bartosz Groele
    2020 Pełny tekst European Research Studies Journal

    Purpose: The objective of this paper is to propose the new indicator of bankruptcy law severity for debtors (BLSI-Bankruptcy Law Severity Index). On the basis of this index we conducted comparative analysis of debtor/creditor friendliness of bankruptcy laws among 27 selected countries. Design/Methodology/Approach: In the research the following methods were used: analysis of legal acts, literature review and expert method. Findings: The empirical results show that the most debtor-friendly bankruptcy and restructuring laws are those of the USA, Ireland and Canada. At the opposite pole were Slovenia, Australia and Austria. It can also be noted that many EU countries have a similar level of BLSI measure, which is most likely a consequence of harmonisation activities undertaken within the Community. Practical Implications: The conducted research enables us to propose the direction of changes in bankruptcy and restructuring laws in the next stage. Originality/value: On the basis of proposed BLSI, we will be able to examine the relationship between the severity of bankruptcy law and innovation, entrepreneurship and the level of development of financial markets in the studied countries.

  • Barriers to and Facilitators of Scientific Productivity: A Case Study from Polish Technical University
    • Magdalena Szuflita-Żurawska
    • Beata Basińska
    • Krzysztof Leja
    2020 Pełny tekst

    Scientific productivity plays an essential role in the creation of innovation and it stimulates social and economic growth. This study aimed to identify the barriers to and facilitators of scientific productivity in engineering and technology field, as perceived from the perspective of academic managers. Along with quality approach, the study relied on semi-structured interviews with managing bodies, i.e. seven deans and deputy deans from four faculties representing scientific field of engineering and technology. A single case study of Polish technical university was analysed in accordance with Braun and Clark’s six-step framework and coded in NVivo software. Findings fell into four themes: scientific publication, recognition, funding research, and collaboration. The results revealed more barriers than facilitators in terms of acceleration of and motivation for research productivity. Most of them related to human, financial, organisational, structural resources, and organizational culture. The novelty of our study lies in the insights into the middle management of universities in the scientific field of engineering and technology in light of the Positive Organisational Scholarship framework.

  • BEHAVIOR OF REINFORCED CONCRETE BEAMS CONTAINING LIGHTWEIGHT AGGREGATE IN THE TENSILE ZONE
    • Jamal Khatib
    • Ali Jahami
    • Oussama Baalbaki
    • Adel Elkordi
    • Hakim Abdelgader
    2020 Pełny tekst BAU Journal - Science and Technology

    .

  • Benchmarking Deep Neural Network Training Using Multi- and Many-Core Processors
    • Paweł Czarnul
    • Klaudia Jabłońska
    2020 International Journal of Computer Information Systems and Industrial Management Applications

    In the paper we provide thorough benchmarking of deep neural network (DNN) training on modern multi- and many-core Intel processors in order to assess performance differences for various deep learning as well as parallel computing parameters. We present performance of DNN training for Alexnet, Googlenet, Googlenet_v2 as well as Resnet_50 for various engines used by the deep learning framework, for various batch sizes. Furthermore, we measured results for various numbers of threads with ranges depending on a given processor(s) as well as compact and scatter affinities. Based on results we formulate conclusions with respect to optimal parameters and relative performances which can serve as hints for researchers training similar networks using modern processors.

  • Bennet
    • Luciano Segreto
    2020

    .

  • Beyond quid pro quo: good soldiers and characteristics of their helping behaviours
    • Joanna Szulc
    2020 Pełny tekst Personnel Review

    Purpose – Good soldiers are people who engage in citizenship behaviours “to do good” instead of “to look good”. The purpose of this article is to explore the motivations behind and the specific characteristics of behaviours of the good soldiers in the context of work using social exchange theory (SET) as a theoretical framework. Design/methodology/approach – 47 dyadic interviews with 94 individuals from three organisations where good soldiers are most likely to be observed were conducted. Findings – Data analysis revealed that good soldiers are driven by concern for others and generalised reciprocity, but not expectations of self-benefits. Their actions were further found to be discretionary, reactive and proactive, and associated with different levels of self-sacrifice. Practical implications – The findings of this study point human resources (HR) practitioners’ attention towards qualitatively unique acts of good soldiers. An assumption is made that awareness of such behaviours can help organisations to stimulate individual self-motivation, so that the quality of helping behaviours could be improved. Originality/value - Arguing for a fundamental rethink of the psychological foundations underpinning helpful behaviours, this paper departs from predominantly individualistic view on work motivation and reinforces the other-oriented, altruistic dimension of SET. In doing so, it addresses the lack of conceptual and theoretical clarity on differently motivated helping and extends the existing limited research evidence in this area. It further addresses a need for a comprehensive understanding of other-oriented behaviours and accounts for vital - yet neglected – features of such acts.

  • Bezpośrednie inwestycje zagraniczne Świat-Europa-Kaukaz-Polska
    • Krystyna Gomółka
    • Elżbieta Kacperska
    • Jakub Kraciuk
    • Michał Wojtaszek
    2020

    W ostatnich dziesięcioleciach bezpośrednie inwestycje zagraniczne należą do najbardziej dynamicznych strumieni międzynarodowych przepływów gospodarczych obok przepływów towarów i usług. Procesy liberalizacji i regionalizacji w dużej mierze przyczyniły się do rosnących przepływów bezpośrednich inwestycji zagranicznych w gospodarce światowej. Przemieszczanie się kapitału w skali międzynarodowej stało się jednym z głównych, i najbardziej pożądanych czynników rozwojowych wielu państwach. W 1970 r. wartość globalnych bezpośrednich inwestycji zagranicznych osiągnęła 13,2 mln USD, zaś w 2018 r. kwotę 1,3 bln USD. Napływ kapitału w postaci bezpośrednich inwestycji zagraniczny do różnych regionów świata cechuje silne zróżnicowanie. Głównymi kreatorami światowych przepływów są kraje rozwinięte, jednak w ostatnich latach dołączyły do tego grona państwa rozwijające się, których udział cały czas ulega wzrostowi. W ostatnich latach obserwujemy zmiany zarówno w strukturze geograficznej, jak też w strukturze rodzajowej bezpośrednich inwestycji zagranicznych. Niniejsze opracowanie jest próbą oceny uwarunkowań, stanu i kierunków zmian międzynarodowych przepływów kapitałowych nastawionych na analizę bezpośrednich inwestycji zagranicznych w ujęciu globalnym i regionalnym. Z uwagi na złożoność problematyki w pracy zawarto jedynie wybrane aspekty. W pierwszej kolejności ukazano teoretyczne przesłanki bezpośrednich inwestycji zagranicznych. Następnie naświetlono empiryczne aspekty bezpośrednich inwestycji zagranicznych w ujęciu globalnym. Ujęcie globalne odnosi się do analizy przepływów bezpośrednich inwestycji w skali świata. Ujęcie regionalne obejmuje analizę przepływów bezpośrednich inwestycji zagranicznych na terenie państw Kaukazu Południowego (Armenii, Azerbejdżanu i Gruzji) oraz na terenie Polski. Polskę przedstawiono jako przykład kraju, który dzięki inwestycjom dokonał znaczącej transformacji gospodarki. Doświadczenia te mogą być wykorzystane przez inne kraje, w tym państwa Kaukazu Południowego. Szczególnie mając na uwadze fakt, że bezpośrednie inwestycje zagraniczne w coraz większym stopniu są lokowane w krajach rozwijających się, w tym w analizowanych krajach Kaukazu Południowego, które mogą jeszcze dzięki inwestycjom zagranicznym wiele zyskać. Zatem przedstawione przykłady mogą być uznane za typowe dla wielu innych krajów na świecie.

  • Bezzałogowy kołowy pojazd elektryczny do automatycznego wychodzenia z poślizgów
    • Juliusz Ciecierski
    • Piotr Drewek
    • Adam Misiak
    • Robert Piotrowski
    2020 Pełny tekst Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

    Pojazdy bezzałogowe znajdują zastosowanie w wielu dziedzinach współczesnego świata. Pojazdy autonomiczne wraz z algorytmami wspomagającymi kierowanie pojazdami skupiają uwagę wielu zespołów inżynierskich. Jednym z ważniejszych aspektów bezpieczeństwa na drogach jest wspomaganie zapobiegania i wychodzenia z poślizgów w dynamicznym środowisku. Artykuł przedstawia projekt oraz wykonanie bezzałogowego pojazdu kołowego zdolnego do automatycznego wychodzenia z poślizgów. Następnie pojazd oprogramowano oraz opracowano aplikację mobilną na urządzenia z systemem Android. Na koniec wykonano badania testowe opracowanego rozwiązania.

  • Będziesz lubić to, co lubisz
    • Jarosław Wawer
    2020 Elektronika dla wszystkich

    Felieton popularno-naukowy dotyczący powstawania baniek informacyjnych/baniek filtrujących.

  • Biblioteka PG uzyskała dofinansowanie z Ministerstwa Nauki i Szkolnictwa Wyższego
    • Kamila Kokot-Kanikuła
    2020 Pismo PG

    „Konserwacja, digitalizacja i udostępnienie 15 wol. zbiorów historycznych z kolekcji Biblioteki PG” to tytuł kolejnego projektu zakwalifikowanego do finansowania w ramach programu ogłoszonego przez Ministerstwo Nauki i Szkolnictwa Wyższego – Społeczna Odpowiedzialność Nauki. Biblioteka otrzyma wsparcie w wysokości 121 tys. zł, przy czym wartość całego przedsięwzięcia wyniesie 136,5 tys. zł.

  • Bidirectional Fragment to Fragment Links in Wikipedia
    • Szymon Olewniczak
    • Tomasz Boiński
    • Julian Szymański
    2020 Pełny tekst

    The paper presents a WikiLinks system that extends the Wikipedia linkage model with bidirectional links between fragments of the articles and overlapping links’ anchors. The proposed model adopts some ideas from the research conducted in a field of nonlinear, computer-aided writing, often called a hypertext. WikiLinks may be considered as a web augmentation tool but it presents a new approach to the problem that addresses the specific nature of Wikipedia. The system, rather than working on the HTML level, works on the wiki code level and augments the Wikipedia content on the parsing phase. WikiLinks is shipped with a new kind of wiki code parser – a parallel markup parser, that allows applying externally-stored links to the content in an elegant way. The system also addresses the problem of bidirectional links' anchors adjustments on the articles' changes, provides a special link evolution procedure and handles the link’s visibility problem. According to our knowledge, this is the first attempt that brings bidirectional links directly to Wikipedia. One of the possible applications of bidirectional fragment-fragment links are associative links. An associative link is a connection between two document fragments that are related to each other in some sense. The new link type extends the current Wikipedia linkage model, dominated by definitional links and provides us an additional tool for content organization, that might be useful for still-growing Wikipedia’s article base. The associative links are from their nature more subjective that definitional ones. In order to test the relevance of this new linkage model, we conducted experiment that checked if the associative links created by one person are understandable to others. The obtained results are very promising and show the usefulness of a new linkage model for Wikipedia.

  • BIG PROBLEMS WITH BIG DATA
    • Krzysztof Goczyła
    2020 Pełny tekst TASK Quarterly

    The article presents an overview of the most important issues related to the phenomenon called big data. The characteristics of big data concerning the data itself and the data sources are presented. Then, the big data life cycle concept is formulated. The next sections focus on two big data technologies: MapReduce for big data processing and NoSQL databases for big data storage.

  • Bioavailability of Tannins and Other Oligomeric Polyphenols: a Still to Be Studied Phenomenon
    • Naira Sahakyan
    • Agnieszka Bartoszek-Pączkowska
    • Jacob Claus
    • Margarit Petrosyan
    • Armen Trchounian
    2020 Current Pharmacology Reports

    Purpose of Review Polyphenols are a group of plant secondary metabolites characterized with the presence ofmultiples of phenol structural units. Tannins are plant originated phenolic substances, which play an important role in plant defense system as well as have found applications in medicine, industry, and other fields of human activity. Despite these, the mechanisms of bioavailability of these substances are poorly studied and even there are very few amounts of sources gathering recent studies concerning this issue. So the main purpose of this review is to focus on the known peculiarities and possible ways of the bioavailability of these oligomeric substances. Recent Findings Due to the ability of tannins to bind proteins and other macromolecules, they are responsible for astringency or bitterness of red wines and also for the anti-nutritional effects, which can be reduced by the action of tannase. In nutriceutical industry, tannins are used as natural preservers and antioxidants. They have also a wide range of medicinal application as antihemorrhagic and hemostatic, anti-malarial and antitumor, antimicrobial, antioxidant, anti-tyrosinase, anthelmintic, antiviral, and anti-inflammatory activities among others. It is suggested that absorption of tannins is correlatedwith their polymerization degree and the activity of these components depends on their absorption in the gut, metabolism and, therefore, the bioavailability. Summary Despite numerous promising applications, there are still plenty of open spaces to fully understand determinants of the bioavailability of tannins and other oligomeric polyphenols pivotal for the expression of their biological activity.

  • Bio-Based Polyurethane Composites and Hybrid Composites Containing a New Type of Bio-Polyol and Addition of Natural and Synthetic Fibers
    • Adam Olszewski
    • Paulina Kosmela
    • Aleksandra Mielewczyk-Gryń
    • Łukasz Piszczyk
    2020 Pełny tekst Materials

    This article describes how new bio-based polyol during the liquefaction process can be obtained. Selected polyol was tested in the production of polyurethane resins. Moreover, this research describes the process of manufacturing polyurethane materials and the impact of two different types of fibers—synthetic and natural (glass and sisal fibers)—on the properties of composites. The best properties were achieved at a reaction temperature of 150 °C and a time of 6 h. The hydroxyl number of bio-based polyol was 475 mg KOH/g. Composites were obtained by hot pressing for 15 minutes at 100 °C and under a pressure of 10 MPa. Conducted researches show the improvement of flexural strength, impact strength, hardness, an increase of storage modulus of obtained materials, and an increase of glass transition temperature of hard segments with an increasing amount of fibers. SEM analysis determined better adhesion of sisal fiber to the matrix and presence of cracks, holes, and voids inside the structure of composites.

  • Bioelectronic tongue: Current status and perspectives
    • Wasilewski Tomasz
    • Wojciech Kamysz
    • Jacek Gębicki
    2020 BIOSENSORS & BIOELECTRONICS

    In the course of evolution, nature has endowed humans with systems for the recognition of a wide range of tastes with a sensitivity and selectivity which are indispensable for the evaluation of edibility and flavour attributes. Inspiration by a biological sense of taste has become a basis for the design of instruments, operation principles and parameters enabling to mimic the unique properties of their biological precursors. In response to the demand for fast, sensitive and selective techniques of flavouring analysis, devices belonging to the group of bioelectronic tongues (B-ETs) have been designed. They combine achievements of chemometric analysis employed for many years in electronic tongues (ETs), with unique properties of bio-inspired materials, such as natural taste receptors (TRs) regarding receptor/ligand affinity. Investigations of the efficiency of the prototype devices create new application possibilities and suggest successful implementation in real applications. With advances in the field of biotechnology, microfluidics and nanotechnologies, many exciting developments have been made in the design of B-ETs in the last five years or so. The presented characteristics of the recent design solutions, application possibilities, critical evaluation of potentialities and limitations as well as the outline of further development prospects related to B-ETs should contribute to the systematisation and expansion of our knowledge.

  • Biogenne aminy
    • Edyta Malinowska-Pańczyk
    2020

    W rozdziale omówiono zagadnienia związane z powstawaniem biogennych amin w surowcach i produktach żywnościowych oraz ich wpływ na zdrowie konsumentów.

  • Biological and mechanical properties of bone cement with nanoarticles - in vitro and in vivo research
    • Beata Świeczko-Żurek
    • Marcin Wekwejt
    • Anita Kajzer
    • Wojciech Kajzer
    • Karolina Siwicka
    • Antonio Ramos
    • Michel Mesnard
    • Jean-marc Olive
    2020 Journal of Mechanical Engineering and Biomechanics

    Despite antibiotic preventive treatment both before and after implant implementation, the risks of infection are real. These infections develop at the implant surface a few months after inserting them into the body. To prevent the development of bacteria and reduce the risk of infection, implants coated with nanoparticles are used. The Mechanical Department of the Technical University of Gdansk carries out research into using bone cement and metal nanoparticles as an alternative to antibiotics [1-3]. Until now, bone cement has been used without a supplement or with one or two drugs. These new experiments included pure bone cement with nanometals, without drugs. The titanium specimens were covered with nanometal coatings. Specimens were inserted into a rat`s thigh for six weeks. The implant was then removed from the body and examined by scanning electron microscope. The results were positive: there was a good adhesion of osteoblasts on the implant surface and there were no traces of infection. Biological research was also carried out. Boneless samples were placed into a bacterial liquid generated by the researcher which contained the five most common bacteria in the human body (Patent no. P409082). Mechanical and corrosion research was carried out at the same time. This confirmed that the modification of bone cement using nanometals has no significant negative effect on the setting time of bone cement, or on the hardness and value of contact angle. In addition, the bone cement coating (with or without nanometals) improved corrosion resistance.

  • Biomateriały we współczesnej medycynie
    • Karolina Czarnecka
    • Mateusz Siwiak
    • Justyna Kucińska-Lipka
    • Jacek Zieliński
    • Helena Janik
    • Michał Pikuła
    2020

    Biomedycyna oznacza eksperymentalne biologiczne i medyczne nauki zintegrowane w całość, w tym nauki chemiczne o związkach wielkocząstoczkowych.

  • Bioterroryzm we współczesnym świecie
    • Marcin Żurek
    • Beata Świeczko-Żurek
    2020

    W definicji wojny biologicznej ważne są słowa dotyczące zastosowania osiągnięć nauki, ponieważ do świadomego i celowego korzystania z broni biologicznej wymagane jest zrozumienie choroby. Gwałtowny rozwój nauk biologicznych i towarzyszące mu liczne odkrycia doprowadziły do większego zainteresowania się bronią biologiczną. Doskonalono techniki hodowli i izolacji kultur mikrobiologicznych. Artykuł opisuje czym jest bioterroryzm i jakie są rodzaje broni biologicznej.

  • Bismuth-Doped Nano Zerovalent Iron: A Novel Catalyst for Chloramphenicol Degradation and Hydrogen Production
    • Murtaza Sayed
    • Aamir Khan
    • Sajid Rauf
    • Noor S. Shah
    • Faiza Rehman
    • Abdullah A. Al-Kahtani
    • Javed Khan
    • Jibran Iqbal
    • Grzegorz Boczkaj
    • Ikhtiar Gul
    • Maleeha Bushra
    2020 Pełny tekst ACS Omega

    In this study, we showed that doping bismuth (Bi) at the surface of Fe0 (Bi/Fe0, bimetallic iron system)—synthesized by a simple borohydride reduction method—can considerably accelerate the reductive degradation of chloramphenicol (CHP). At a reaction time of 12 min, 62, 68, 74, 95, and 82% degradation of CHP was achieved with Fe0, Bi/Fe0-1 [1% (w/w) of Bi], Bi/Fe0-3 [3% (w/w) of Bi], Bi/Fe0-5 [5% (w/w) of Bi], and Bi/Fe0-8 [8% (w/w) of Bi], respectively. Further improvements in the degradation efficiency of CHP were observed by combining the peroxymonosulfate (HSO5–) with Bi/Fe0-5 (i.e., 81% by Bi/Fe0-5 and 98% by the Bi/Fe0-5/HSO5– system at 8 min of treatment). Interestingly, both Fe0 and Bi/Fe0-5 showed effective H2 production under dark conditions that reached 544 and 712 μM by Fe0 and Bi/Fe0-5, respectively, in 70 mL of aqueous solution containing 0.07 g (i.e., at 1 g L–1 concentration) of the catalyst at ambient temperature.

  • Blood Pressure - Pulse Transit Time Relationships: Comparative Studies
    • Artur Poliński
    • Adam Bujnowski
    • Tomasz Kocejko
    • Jerzy Wtorek
    2020

    A non-invasive and continuous blood pressure estimation could allow a better diagnosis and an earlier detection of various diseases. It could be performed using a photoplethysmography. However, it requires that a relation between blood pressure and pulse transit time is known. Eleven theoretical formulas were used in obtaining the simulated and noise free synthetic data. Then, they were utilized in validation of three, commonly used, formulas for blood pressure estimation. Finally, the best one was indicated

  • Blowing Kinetics, Pressure Resistance, Thermal Stability, and Relaxation of the Amorphous Phase of the PET Container in the SBM Process with Hot and Cold Mold. Part I: Research Methodology and Results
    • Paweł Wawrzyniak
    • Waldemar Karaszewski
    2020 Pełny tekst Polymers

    The technology of filling drinks without preservatives (such as fresh juices, iced tea drinks, vitaminized drinks) is carried out using hot filling. Mainly due to the production costs and lower carbon footprint, polyethylene terephthalate bottles, commonly called PET, are increasingly used in this technology. In this paper, the main aim is to describe the statistical analysis methodology of the influence of the temperature of the blow mold in the SBM process and the method of hot filling on the macroscopic and microscopic bottle properties. The macroscopic bottle properties were defined by the thickness profile, pressure resistance, thermal stability, and the coefficients of blowing kinetics. Moreover, the influence of the SBM (stretch blow moulding) process on the microscopic PET material properties (in the bottle) relative to the microscopic preform properties was analyzed. The microscopic properties were defined by the degree of crystallite, density, and relaxation of the amorphous phase of the PET material. For this purpose, response surface experiments were performed for the two analyzed factors (independent variables), i.e., the temperature of the blow mold and the method of hot filling. The sample size was investigated to determine the minimum number of repetitions (number of bottles in the measurement series) required to achieve acceptable measurement uncertainty. The research conducted shows that despite fulfilling the postulate of acceptable measurement uncertainty, in terms of the power of ANOVA (analysis of variance) in DOE (design of experiment) the accepted number of bottles in the measurement series is too small. The tests of the bottle material density, material crystallite, and relaxation of amorphous phase relative to the preform material density, material crystallite, and relaxation of amorphous phase show that the microcavity effects occur during the deformation of the PET material, and that these are associated with the orientation of the microstructure. The blow kinetics study shows that there is a gradient of flow of the bottle material over the thickness of the bottle wall during blowing, and it has been deduced that the air temperature between the blow mold and the wall of the blown bottle has an impact on the kinetics of blowing the bottle.

  • Blowing Kinetics, Pressure Resistance, Thermal Stability, and Relaxation of the Amorphous Phase of the PET Container in the SBM Process with Hot and Cold Mold. Part II: Statistical Analysis and Interpretation of Tests
    • Paweł Wawrzyniak
    • Waldemar Karaszewski
    2020 Pełny tekst Polymers

    The technology of filling drinks without preservatives (such as fresh juices, iced tea drinks, and vitaminized drinks) is carried out using hot filling. Mainly due to the production costs and lower carbon footprint, polyethylene terephthalate (PET) bottles are increasingly used in this technology. In this paper, the main aim is to describe and interpret the results of statistical analysis of the influence of the temperature of the blow mold in the SBM (stretch blow molding) process and the method of hot filling on the macroscopic and microscopic bottle properties. The macroscopic bottle properties were defined by the thickness profile, pressure resistance, thermal stability, and the coefficients of blowing kinetics. In addition, the influence of the SBM process on the microscopic PET material properties (in the bottle) relative to the microscopic preform properties was analyzed. The microscopic properties were defined by the degree of crystallite, density, and relaxation of the amorphous phase of the PET material. For this purpose, response surface experiments were performed for the two analyzed factors, i.e. the temperature of the blow mold and the method of hot filling. The sample size was investigated to determine the minimum number of repetitions (number of bottles in the measurement series) required to achieve acceptable measurement uncertainty. The research conducted shows that, despite fulfilling the postulate of acceptable measurement uncertainty, in terms of the power of ANOVA (analysis of variance) in DOE (design of experiment), the accepted number of bottles in the measurement series is too small. The tests of the bottle material density, material crystallite, and relaxation of amorphous phase relative to the preform material density, material crystallite, and relaxation of amorphous phase show that microcavity effects occur during the deformation of the PET material, and that these are associated with the orientation of the microstructure. The blow kinetics study shows that there is a gradient of flow of the bottle material over the thickness of the bottle wall during blowing, and it has been deduced that the air temperature between the blow mold and the wall of the blown bottle has an impact on the kinetics of blowing the bottle.

  • Blurred quantum Darwinism across quantum reference frames
    • Thao P. Le
    • Piotr Mironowicz
    • Paweł Horodecki
    2020 Pełny tekst PHYSICAL REVIEW A

    Quantum Darwinism describes objectivity of quantum systems via their correlations with their environment--information that hypothetical observers can recover by measuring the environments. However, observations are done with respect to a frame of reference. Here, we take the formalism of [Giacomini, Castro-Ruiz, & Brukner. Nat Commun 10, 494 (2019)], and consider the repercussions on objectivity when changing quantum reference frames. We find that objectivity depends on non-degenerative relative separations, conditional state localisation, and environment macro-fractions. There is different objective information in different reference frames due to the interchangeability of entanglement and coherence, and of statistical mixing and classical correlations. As such, objectivity is subjective across quantum reference frames.

  • Bounded solutions of odd nonautonomous ODE
    • Zdzisław Dzedzej
    2020 Pełny tekst TOPOLOGY AND ITS APPLICATIONS

    Borsuk-Ulam type argument is used in order to prove exstence of nontrivial bounded solutions to some nonautonomous differential euations which are odd with respect to the spatial variable. A Poincare compactification trick is also applied.

  • BPL-PLC Voice Communication System for the Oil and Mining Industry
    • Grzegorz Debita
    • Przemysław Falkowski-Gilski
    • Marcin Habrych
    • Grzegorz Wiśniewski
    • Bogdan Miedziński
    • Przemysław Jedlikowski
    • Agnieszka Waniewska
    • Jan Wandzio
    • Bartosz Polnik
    2020 Pełny tekst ENERGIES

    Application of a high-efficiency voice communication systems based on broadband over power line-power line communication (BPL-PLC) technology in medium voltage networks, including hazardous areas (like the oil and mining industry), as a redundant mean of wired communication (apart from traditional fiber optics and electrical wires) can be beneficial. Due to the possibility of utilizing existing electrical infrastructure, it can significantly reduce deployment costs. Additionally, it can be applied under difficult conditions, thanks to battery-powered devices. During an emergency situation (e.g., after coal dust explosion), the medium voltage cables are resistant to mechanical damage, providing a potentially life-saving communication link between the supervisor, rescue team, paramedics, and the trapped personnel. The assessment of such a system requires a comprehensive and accurate examination, including a number of factors. Therefore, various models were tested, considering: different transmission paths and types of coupling (inductive and capacitive), as well as various lengths of transmitted data packets. Next, a subjective quality evaluation study was carried out, considering speech signals from a number of languages (English, German, and Polish). Based on the obtained results, including both simulations and measurements, appropriate practical conclusions were formulated. Results confirmed the applicability of BPL-PLC technology as an efficient voice communication system for the oil and mining industry.

  • Bridge of Knowledge: an Internet platform for R2R and R2B transfer of knowledge and promotion of cooperation
    • Henryk Krawczyk
    • Paweł Lubomski
    2020 Pełny tekst TASK Quarterly

    Currently, the European Commission puts emphasis on supporting collaboration between universities and business. There are many possible ways to create a strong relationship between both these parties. Positive results of such cooperation lead to increased competitiveness of the global market and, in consequence, bring significant growth of innovation. The cooperation between research-to-research (R2R) and research-to-business (R2B) is analysed. The paper shows how the IT technology can be used to support and stimulate it. In our University we proposed a two-step strategy. Firstly, we tried to improve collaboration among scientists in order to develop R2R activities. Secondly, we focused on R2B projects that stimulate promising scientists to take part in various innovative activities carried out in cooperation with the industry representatives. Based on some well-known good practices a special Internet platform was designed and implemented to support such a strategy. Its name is the “Bridge of Knowledge”. The platform architecture, its functionality and some other aspects of the development process are described. The platform was developed and introduced at the Gdańsk University of Technology. It has been available online for nearly 2 years now and it has been attracting increasing numbers of new visitors and returning users. Several use cases of cooperation between R2R and R2B were analysed and described with the use of advanced analytic tools and on the basis of the organisation’s resources. The idea of the Bridge of Knowledge platform is to gather and share resources not only from one university. The architecture of the platform focuses on a wide and easy interoperability. Other universities can share their resources without any additional cost.

  • Bringing Bathymetry LiDAR to Coastal Zone Assessment: A Case Study in the Southern Baltic
    • Paweł Tysiąc
    2020 Pełny tekst Remote Sensing

    One of the major tasks in environmental protection is monitoring the coast for negative impacts due to climate change and anthropopressure. Remote sensing techniques are often used in studies of impact assessment. Topographic and bathymetric procedures are treated as separate measurement methods, while methods that combine coastal zone analysis with underwater impacts are rarely used in geotechnical analyses. This study presents an assessment of the bathymetry airborne system used for coastal monitoring, taking into account environmental conditions and providing a comparison with other monitoring methods. The tests were carried out on a section of the Baltic Sea where, despite successful monitoring, coastal degradation continues. This technology is able to determine the threat of coastal cliff erosion (based on the geotechnical analyses). Shallow depths have been reported to be a challenge for bathymetric Light Detection and Ranging (LiDAR), due to the difficulty in separating surface, water column and bottom reflections from each other. This challenge was overcome by describing the classification method used which was the CANUPO classification method as the most suitable for the point cloud processing. This study presents an innovative approach to identifying natural hazards, by combining analyses of coastal features with underwater factors. The main goal of this manuscript is to assess the suitability of using bathymetry scanning in the Baltic Sea to determine the factors causing coastal erosion. Furthermore, a geotechnical analysis was conducted, taking into account geometrical ground change underwater. This is the first study which uses a coastal monitoring approach, combining geotechnical computations with remote sensing data. This interdisciplinary scientific research can increase the awareness of the environmental processes.

  • Buckling analysis of a non-concentric double-walled carbon nanotube
    • Mohammad Malikan
    • Victor Eremeev
    • Hamid M. Sedighi
    2020 Pełny tekst ACTA MECHANICA

    On the basis of a theoretical study, this research incorporates an eccentricity into a system of compressed double-walled carbon nanotubes (DWCNTs). In order to formulate the stability equations, a kinematic displacement with reference to the classical beam hypothesis is utilized. Furthermore, the influence of nanoscale size is taken into account with regard to the nonlocal approach of strain gradient and the van der Waals interaction for both inner and outer tubes is also considered based on the Lennard-Jones model. Galerkin decomposition technique is employed to numerically deal with the governing equations. It is evidently demonstrated that the geometrical eccentricity remarkably affects the stability threshold and its impact is to increase the static stability of DWCNTs.

  • Budownictwo morskie. Wybrane zagadnienia wraz z przykładami obliczeniowymi
    • Waldemar Magda
    2020

    Jednym z głównych zadań projektanta budowli morskiej jest poprawne uwzględnienie kombinacji oddziaływań takich czynników jak: falowanie, prądy morskie, wiatr, zjawiska sejsmiczne. Innym istotnym elementem jego pracy jest zagwarantowanie spełnienia warunków stateczności budowli poprzez umiejętną analizę współoddziaływania środowiska morskiego i budowli morskiej z jednoczesnym interaktywnym projektowaniem geometrii budowli oraz doborem właściwych parametrów materiałowych. Niniejsza publikacja dotyczy wybranych zagadnień związanych z inżynierią morską. Na przykładzie typowych budowli morskich: falochronu pionowościennego, falochronu narzutowego oraz rurociągu podmorskiego przedstawiono metody umożliwiające określenie obciążenia tych budowli – zarówno w postaci obciążenia hydrostatycznego, jak i obciążenia hydrodynamicznego. Autor krok po kroku prezentuje szczegółowe rozwiązania licznych zadań rachunkowych, w których uwzględniono typowe schematy obciążeń, możliwe do zaistnienia w warunkach rzeczywistej pracy budowli morskiej. Aby ułatwić Czytelnikowi do maksimum osiągnięcie pozytywnych wyników samokształcenia na bazie prezentowanej książki, autor daje Czytelnikowi możliwość skorzystania z darmowej wersji wykonawczej autorskiego programu komputerowego, przygotowanego specjalnie jako uzupełnienie materiału przedstawionego w książce. Książka przeznaczona jest dla pracowników biur projektów budownictwa hydrotechnicznego, osób na stanowiskach związanych z projektowaniem, wykonawstwem i nadzorem w czasie procesu inwestycyjnego, a także pracowników naukowych oraz studentów budownictwa hydrotechnicznego i inżynierii morskiej i brzegowej.

  • Bulk-Surface Modification of Nanoparticles for Developing Highly-Crosslinked Polymer Nanocomposites
    • Maryam Jouyandeh
    • Mohammad Ganjali
    • Mustafa Aghazadeh
    • Sajjad Habibzadeh
    • Krzysztof Formela
    • Mohammad Saeb
    2020 Pełny tekst Polymers

    Surface modification of nanoparticles with functional molecules has become a routine method to compensate for diffusion-controlled crosslinking of thermoset polymer composites at late stages of crosslinking, while bulk modification has not carefully been discussed. In this work, a highly-crosslinked model polymer nanocomposite based on epoxy and surface-bulk functionalized magnetic nanoparticles (MNPs) was developed. MNPs were synthesized electrochemically, and then polyethylene glycol (PEG) surface-functionalized (PEG-MNPs) and PEG-functionalized cobalt-doped (Co-PEG-MNPs) particles were developed and used in nanocomposite preparation. Various analyses including field-emission scanning electron microscopy, Fourier-transform infrared spectrophotometry (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and vibrating sample magnetometry (VSM) were employed in characterization of surface and bulk of PEG-MNPs and Co-PEG-MNPs. Epoxy nanocomposites including the aforementioned MNPs were prepared and analyzed by nonisothermal differential scanning calorimetry (DSC) to study their curing potential in epoxy/amine system. Analyses based on Cure Index revealed that incorporation of 0.1 wt.% of Co-PEG-MNPs into epoxy led to Excellent cure at all heating rates, which uncovered the assistance of bulk modification of nanoparticles to the crosslinking of model epoxy nanocomposites. Isoconversional methods revealed higher activation energy for the completely crosslinked epoxy/Co-PEG-MNPs nanocomposite compared to the neat epoxy. The kinetic model based on isoconversional methods was verified by the experimental rate of cure reaction.

  • Burnout as a State: Random-Intercept Cross-Lagged Relationship Between Exhaustion and Disengagement in a 10-Day Study
    • Beata Basińska
    • Ewa Gruszczyńska
    2020 Pełny tekst Psychology Research and Behavior Management

    Background: Burnout has been traditionally seen as a chronic and stable state in response to prolonged stress. However, measures of momentary burnout are not well established, even though the within-person approach suggests that the symptoms of burnout may vary from day to day for the same employee. The aim of this study is to examine the daily inter- and intra-personal variability of the symptoms of burnout and the cross-lagged relationship between two components of burnout, exhaustion and disengagement. Methods: An online diary study over 10 consecutive workdays was conducted among 235 civil servants (75% women, average tenure of 15 years). Daily burnout was measured with the eight-item Oldenburg Burnout Inventory. Results: The intra-class correlation coefficients indicate that, although significant betweenperson variability exists, most of the burnout variance is within persons. Using the random intercept cross-lagged panel (RI-CLP) model to control for these between-person differences, mainly insignificant “pure” within-person cross-lagged relationships between exhaustion and disengagement were revealed. Moreover, day-to-day autoregressive effects were weaker than same-day residual correlations. Conclusion: This is one of the first studies to use daily diaries and the RI-CLP model to study burnout, including the separation of the more stable and more dynamic parts of each component. When stable parts were controlled for, the same-day relationships between exhaustion and disengagement were more pronounced than day-to-day effects. This might suggest stronger situational influences than carryover mechanism. Thus, conceptualizing burnout in terms of daily symptoms may shed promising insights into how it develops and add implications for pro-healthy changes in the workplace.

  • Burnout as a State: Random-Intercept Cross-Lagged Relationship Between Exhaustion and Disengagement in a 10-Day Study [Response to Letter]
    • Beata Basińska
    • Ewa Gruszczyńska
    2020 Psychology Research and Behavior Management

    We are writing in response to the Letter to the Editor by Block, Bair, and Carillo regarding our study, which took a multilevel approach to examine cross-lagged and co-existing relationships between exhaustion and disengagement, measured daily for ten consecutive working days using the Oldenburg Burnout Inventory (OLBI). We assessed the job burnout symptoms using only eight items, all of them worded negatively. Following Block, Bair, and Carillo’s request, we are happy to provide supplementary cross-sectional results from the first day of our study.

  • Buzz-based recognition of the honeybee colony circadian rhythm
    • Tymoteusz Cejrowski
    • Julian Szymański
    • Doina Logofătu
    2020 Pełny tekst COMPUTERS AND ELECTRONICS IN AGRICULTURE

    Honeybees are one of the highly valued pollinators. Their work as individuals is appreciated for crops pollination and honey production. It is believed that work of an entire bee colony is intense and almost continuous. The goal of the work presented in this paper is identification of bees circadian rhythm with a use of sound-based analysis. In our research as a source of information on bee colony we use their buzz that have been analysed using algorithms. For the purpose of bees day/night definition, a dedicated electronic system has been developed. The data analysis involves demonstration of the circadian rhythm based on the RMS signal level. Method for defining the start and end of the presumed bees’ night was also presented. Mel Frequency Cepstral Coefficients (MFCCs) features and SVM classifier were used. The performed experiment shown the existence of repetitive cycles, which may indicate the presence of bee night. An attempt was made to estimate the time range of this phenomenon.

  • Can high hydrostatic pressure processing be the best way to preserve human milk?
    • Edyta Malinowska-Pańczyk
    2020 Pełny tekst TRENDS IN FOOD SCIENCE & TECHNOLOGY

    Breastfeeding is one of the most important factors influencing proper child development. When a mother cannot breastfeed, the best alternative, especially for feeding premature infants, is to then use of human milk (HM) which has been collected, preserved and stored in Human Milk Banks (HMB). Scope and approach: In this review, the impact of some stages of the management of HM in HMB on its final biological value and microbiological safety are described. Negative changes in HM components begin during the first stage of frozen storage. In the next stages, further losses occur, which largely depend on the applied method of microbiota elimination. Complete inactivation of milk microbiota can be achieved after pressurization in the range 500-600 MPa, but similarly for holder pasteurization (HoP), in these conditions unfavorable changes in the milk components take place. At lower pressures, the changes are smaller, but microbiological safety of HM is not achieved. Key findings and conclusions: Replacing HoP with pressurization does not seem to be justified so far, not only because of the small differences in the retention of valuable HM ingredients, but also because of the high costs associated with the inclusion of the device for generating pressure in the HMB environment. A new solution may be the use of high-pressure milk storage at subzero temperatures, but this hypothesis must be verified.

  • Capacitance Enhancement by Incorporation of Functionalised Carbon Nanotubes into Poly(3,4-Ethylenedioxythiophene)/Graphene Oxide Composites
    • Anita Cymann
    • Mirosław Sawczak
    • Jacek Ryl
    • Ewa Klugmann-Radziemska
    • Monika Wilamowska-Zawłocka
    2020 Pełny tekst Materials

    This paper reports on the role of oxidised carbon nanotubes (oxMWCNTs) present in poly-3,4-ethylenedioxytiophene (PEDOT)/graphene oxide (GOx) composite. The final ternary composites (pEDOT/GOx/oxMWCNTs) are synthesised by an electrodeposition process from the suspension-containing monomer, oxidised carbon nanotubes and graphene oxide. Dissociated functional groups on the surface of graphene oxide play a role of counter-ions for the polymer chains. Detailed physicochemical and electrochemical characterisation of the ternary composites is presented in the paper. The results prove that the presence of oxMWCNTs in the ternary composites doubles the capacitance values compared to the binary ones (450 vs. 270 F cm3 for PEDOT/GOx/oxMWCNTs and PEDOT/GOx, respectively). The amount of carbon nanotubes in the synthesis solution is crucial for physicochemical properties of the composites, their adhesion to the electrode substrate and the electrochemical performance.

  • Carbon Dioxide Recovery Skid
    • Kamil Stasiak
    • Paweł Ziółkowski
    • Dariusz Mikielewicz
    2020 Pełny tekst Progress in Petrochemical Science

    In the face of tightening climate regulations, the adoption of carbon dioxide recovery systems is inevitable. Modular process skid units have been widely adopted across the industry. The gas-steam power plant skid unit with the carbon dioxide recovery system was described. The proposed skid module consists of the compact cycle with the oxy-combustion and the carbon dioxide capture skid unit producing pure compressed CO2. The compactness of the suggested skid can be achieved due to a novel small size designs of the wet combustion chamber and the spray-ejector condenser.

  • Carbon Nanomaterials From Metal-Organic Frameworks: A New Material Horizon for CO2 Reduction
    • Xiaoxu Xuan
    • Songying Chen
    • Shan Zhao
    • Joon Yong Yoon
    • Grzegorz Boczkaj
    • Xun Sun
    2020 Pełny tekst Frontiers in Chemistry

    The rise of CO2 in the atmosphere, which results in severe climate change and temperature increase, is known as the major reason for greenhouse effect. Reducing CO2 to value-added products is an attractive solution to this severe problem, along with addressing the energy crisis, to which the catalysts being employed are of vital importance. Due to their high porosity and tunable compositions, Metal-Organic Frameworks (MOFs) show great potentials in energy conversion systems. By thermal or chemical treatment methods, the MOFs are easily turned to MOF derived carbon nanomaterials. The much higher conductivity enables MOF derived carbon nanomaterials to be employed in CO2 conversion processes. The present review, discusses the state of the art of MOF derived carbon nanomaterials in CO2 electrochemical, photocatalytic, and thermal reduction applications. The corresponding reaction mechanisms and influence of various factors on catalyst performance are elaborated. Finally, the deficiencies and recommendations are provided for the future progress.

  • Carboxylation Enhances Fragmentation of Furan upon Resonant Electron Attachment
    • Mateusz Zawadzki
    • Thomas F. M. Luxford
    • Jaroslav Kočišek
    2020 Pełny tekst JOURNAL OF PHYSICAL CHEMISTRY A

    We report a dissociative electron attachment study to 2-furoic acid (C5H4O3) isolated in a gas phase, which is a model molecule consisting of a carboxylic group and a furan ring. Dissociation of furan by low energy electrons is accessible only via electronic excited Feshbach resonances at energies of incident electrons above 5 eV. On the other hand, carboxylic acids are well- known to dissociate via attachment of electrons at subexcitation energies. Here we elucidate how the electron and proton transfer reactions induced by carboxylation influence stability of the furan ring. Overlap of the furan and carboxyl π orbitals results in transformation of the nondissociative π2 resonance of the furan ring to a dissociative resonance. The interpretation of hydrogen transfer reactions is supported by experimental studies of 3-methyl-2-furoic and 5-methyl-2-furoic acids (C6H6O3) and density functional theory (DFT) calculations.

  • Cargo ships heat demand - operational experiment
    • Damian Bocheński
    • Dominik Kreft
    2020 Pełny tekst Polish Maritime Research

    The paper presents the results of an experiment conducted on two cargo ships – a 5300 TEU container with a steam heating system and a 7500 dwt general cargo ship with a thermal oil system. On both ships research has been carried out using specially designed measuring equipment. After gathering data about flow velocity and temperatures (steam/ cooling water/ thermal oil/ seawater/ outside air), calculations have been done, resulting in histograms. For both types of histograms (heat demand and service time), the probability density function was fitted, using the K-S statistical test. The last step was comparison of the probability distribution mean to seawater and the outside air temperatures by linear regression and the coefficient of determination. The dependencies between the mentioned temperatures and heat demand were noted.

  • Carnivorous plants used for green synthesis of silver nanoparticles with broad-spectrum antimicrobial activity
    • Rafal Banasiuk
    • Marta Krychowiak
    • Daria Swigon
    • Wojciech Tomaszewicz
    • Angelika Michalak
    • Agnieszka Chylewska
    • Magdalena Ziabka
    • Marcin Stanisław Łapiński
    • Barbara Kościelska
    • Magdalena Narajczyk
    • Aleksandra Krolicka
    • Marta Krychowiak-Maśnicka
    2020 Pełny tekst Arabian Journal of Chemistry

    In this study, we exploit the anti-oxidative potential of four carnivorous plants to produce uniform and biologically active silver nanoparticles. The use of polyvinylpyrrolidone promoted syn-thesis of quasi-spherical nanoparticles characterized by stability and high uniformity. Their activity was tested against three human pathogens and three species of plant pathogenic bacteria. The study demonstrates the influence of synthesis method (microwave irradiation or heat radiation) and plant extract composition on nanoparticle activity. The total anti-oxidative potential of the plant extract, as well as the applied method of silver ions reduction proved to be crucial for antimicrobial activity. The highest minimal bactericidal concentration (mean value = 10 m g/mL) was obtained for silver nanoparticles synthesized with the use of water extract from Dionaea muscipula tissue.

  • Carrefour
    • Luciano Segreto
    2020

    .

  • Cascading transitions toward unconventional charge density wave states in the quasi-two-dimensional monophosphate tungsten bronze P4W16O56
    • Elen Duverger-Nédellec
    • Alain Pautrat
    • Kamil Kolincio
    • Laurence Hervé
    • Olivier Pérez
    2020 Pełny tekst IUCrJ

    Single crystals of the m = 8 member of the low-dimensional monophosphate tungsten bronzes (PO2)4(WO3)2m family were grown by chemical vapour transport technique and the high crystalline quality obtained allowed a reinvestigation of the physical and structural properties. Resistivity measurements revealed three anomalies at TC1 = 258 K, TC2 = 245 K and TC3 = 140 K, never observed until now. Parallel X-ray diffraction investigations showed a specific signature associated with three structural transitions, i.e. the appearance of different sets of satellite reflections below TC1, TC2 and TC3. Several harmonics of intense satellite reflections were observed, reflecting the non-sinusoidal nature of the structural modulations and a strong electron–phonon coupling in the material. These transitions could be associated with the formation of three successive unconventional charge density wave states.

  • Cassirer E. .Filozofia form symbolicznych. Część Druga: Myślenie Mityczne.Przekład, wstęp i opracowanie Andrzej Karalus i Przemysław Parszutowicz, Kęty: Wydaw.Marek Derewiecki,2020
    • Andrzej Karalus
    • Przemysław Parszutowicz
    2020

    Tłumaczenie ksiązki: Andrzej Karalus i Przemysław Parszutowicz

  • Catalytic Mechanism of Non-Target DNA Cleavage in CRISPR-Cas9 Revealed by Ab Initio Molecular Dynamics
    • Lorenzo Casalino
    • Łukasz Nierzwicki
    • Martin Jinek
    • Giulia Palermo
    2020 Pełny tekst ACS Catalysis

    CRISPR-Cas9 is a cutting-edge genome editing technology, which uses the endonuclease Cas9 to introduce mutations at desired sites of the genome. This revolutionary tool is promising to treat a myriad of human genetic diseases. Nevertheless, the molecular basis of DNA cleavage, which is a fundamental step for genome editing, has not been established. Here, quantum–classical molecular dynamics (MD) and free energy methods are used to disclose the two-metal-dependent mechanism of phosphodiester bond cleavage in CRISPR-Cas9. Ab initio MD reveals a conformational rearrangement of the Mg2+-bound RuvC active site, which entails the relocation of H983 to act as a general base. Then, the DNA cleavage proceeds through a concerted associative pathway fundamentally assisted by the joint dynamics of the two Mg2+ ions. This clarifies previous controversial experimental evidence, which could not fully establish the catalytic role of the conserved H983 and the metal cluster conformation. The comparison with other two-metal-dependent enzymes supports the identified mechanism and suggests a common catalytic strategy for genome editing and recombination. Overall, the non-target DNA cleavage catalysis described here resolves a fundamental open question in the CRISPR-Cas9 biology and provides valuable insights for improving the catalytic efficiency and the metal-dependent function of the Cas9 enzyme, which are at the basis of the development of genome editing tools.

  • Cathodic activation of synthesized highly defective monoclinic hydroxyl‐functionalized ZrO2 nanoparticles for efficient electrochemical production of hydrogen in alkaline media
    • Nasser Mostafa
    • M. Qhtani
    • S. Alotaibi
    • Z. Zaki
    • Sarah Alharthi
    • Mateusz Cieślik
    • Adrianna Górnicka
    • Jacek Ryl
    • Rabah Boukherroub
    • Mohammed Amin
    2020 Pełny tekst INTERNATIONAL JOURNAL OF ENERGY RESEARCH

    The high electrochemical stability of Zirconia (ZrO2) at high potentials strongly suggested it as an alternative to carbon supports, which experience reduced efficiency due to some corrosion problems particularly during prolonged electrocatalysis activity. However, the use of ZrO2 was limited by its low electrical conductivity and surface area. In this work, we developed a methodology for synthesizing monoclinic ZrO2 NPs with increased surface area and improved electrical/electrocatalytic characteristics without using any carbon‐based co‐support material or any metallic nanoparticles. In this context, for the first time, highly defective hydroxyl‐functionalized ZrO2 NPs (designated here as ZT NPs) were prepared by a hydrothermal route in the presence of sodium tartrate as a mineralizer. XRD analysis demonstrated that the produced zirconia was semicrystalline microspheres, consisting of monoclinic ZrO2 NPs with high lattice defects. The addition of tartrate ions decreased the crystallite size and increased the defects and microstrain. At the same time, the alkaline hydrogen evolution reaction (HER) catalytic activity of ZrO2 NPs was significantly increased when using sodium tartrate as mineralizer; the overpotential required to obtain 10 mA cm−2 (η10) dropped down from 490 to merely 235 mV, while an exchange current density (jo) increased 12 times to 0.22 mA cm−2. The presence of structural defects (revealed by XRD) and the increased number of active surface sites contending O‐H groups (evidenced from ATR‐FTIR and XPS) as well as the enhanced electrochemical active surface area (confirmed from double‐layer capacitance measurements) were the main reasons behind the high catalytic performance. The ZrO2 NPs catalytic activity increased even further during the long‐term stability tests under severe cathodic conditions (ZT*, ZrO2 NPs obtained after the long‐term stability, has jo = 0.47 mA cm−2 and η10 = 140 mV), approaching the activity of Pt/C catalyst. This process was assisted by mineralizer removal from the catalyst (testified by XPS). Our studies revealed that ZT* are characterized by larger electroactive surface area and more structure defects compared to ZT, where surface area and microstrains resulting from surface hydroxylation open cavities in zirconia structure.

  • Cellulose Nanofibers Isolated from the Cuscuta Reflexa Plant as a Green Reinforcement of Natural Rubber
    • Midhun Dominic C.D.
    • Rani Joseph
    • P.M. Sabura Begum
    • Meera Joseph
    • Dileep Padmanabhan
    • Leonna Angela Morris
    • Athira S Kumar
    • Krzysztof Formela
    2020 Pełny tekst Polymers

    In the present work, we used the steam explosion method for the isolation of cellulose nanofiber (CNF) from Cuscuta reflexa, a parasitic plant commonly seen in Kerala and we evaluated its reinforcing efficiency in natural rubber (NR). Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Thermogravimetric analysis (TGA) techniques indicated that type I cellulose nanofibers, with diameter: 10–30 nm and a 67% crystallinity index were obtained by the proposed method. The results showed that application of CNF in NR based nanocomposites resulted in significant improvement of their processing and performance properties. It was observed that the tensile strength and tear strength of NR/CNF nanocomposites are found to be a maximum at 2 phr CNF loading, which corresponds with the studies of equilibrium swelling behavior. Dynamic mechanical analysis, thermogravimetric analysis, and morphological studies of tensile fractured samples also confirm that CNF isolated from Cuscuta reflexa plant can be considered as a promising green reinforcement for rubbers.

  • CENTRUM w systemie STRADAR – funkcje, architektura i realizacja
    • Marek Blok
    • Sylwester Kaczmarek
    • Magdalena Młynarczuk
    2020 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    System STRADAR jest rozwiązaniem umożliwiającym utworzenie infrastruktury komunikacyjno-teleinformatycznej przeznaczonej dla Morskiego Oddziału Straży Granicznej. Artykuł ten jest kolejną z cyklu publikacji opisujących architekturę i rozwiązanie systemu i dotyczy jego centralnego elementu, jakim jest CENTRUM. Przedstawiono i opisano funkcje, architekturę i realizację oprogramowania CENTRUM, które może być zainstalowane na dowolnym serwerze ze środowiskiem Linux. Oprogramowanie to przeszło pozytywnie testy akceptacyjne w ramach zrealizowanego prototypu systemu.

  • Ceramic composites for single-layer fuel cells
    • Piotr Winiarz
    • Tadeusz Miruszewski
    • Sebastian Wachowski
    • Kacper Dzierzgowski
    • Iga Szpunar
    • Krzysztof Zagórski
    • Aleksandra Mielewczyk-Gryń
    • Maria Gazda
    2020 Pełny tekst SOLID STATE SCIENCES

    Composite materials consisting of acceptor doped lanthanum orthoniobate electrolyte phase (La0.98Ca0.02NbO4) and Li2O:NiO:ZnO semiconducting phase were synthesized. The precursor powder of La0.98Ca0.02NbO4 was prepared in nanocrystalline (mechanosynthesis) and microcrystalline (solid-state synthesis) form. The composite can be applied in a single-layer fuel cell, because of the presence of two phases acting as an anode and a cathode simultaneously. X-ray diffraction data show that the materials consist of two expected phases. Scanning Electron Microscope images, with Energy Dispersive X-Ray analysis show that La0.98Ca0.02NbO4 as well as Li2O:NiO:ZnO are mixed together in the volume of the material. Open circuit voltage both for nano- and microcrystalline composite do not exceed 0.8 V. The single-layer fuel cell is degrading upon time and the voltage drop is observed. The processes of ZnO reduction and Zn diffusion and evaporation as responsible for cell degradation are discussed.

  • Certified domination
    • Magda Dettlaff
    • Magdalena Lemańska
    • Jerzy Topp
    • Radosław Ziemann
    • Paweł Żyliński
    2020 Pełny tekst AKCE International Journal of Graphs and Combinatorics

    Imagine that we are given a set D of officials and a set W of civils. For each civil x ∈ W, there must be an official v ∈ D that can serve x, and whenever any such v is serving x, there must also be another civil w ∈ W that observes v, that is, w may act as a kind of witness, to avoid any abuse from v. What is the minimum number of officials to guarantee such a service, assuming a given social network? In this paper, we introduce the concept of certified domination that models the aforementioned problem. Specifically, a dominating set D of a graph G = (VG, EG) is said to be certified if every vertex in D has either zero or at least two neighbours in VG \ D. The cardinality of a minimum certified dominating set in G is called the certified domination number of G. Herein, we present the exact values of the certified domination number for some classes of graphs as well as provide some upper bounds on this parameter for arbitrary graphs. We then characterise a wide class of graphs with equal domination and certified domination numbers and characterise graphs with large values of certified domination numbers. Next, we examine the effects on the certified domination number when the graph is modified by deleting/adding an edge or a vertex. We also provide Nordhaus–Gaddum type inequalities for the certified domination number.