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Gdańsk University of Technology

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  • Neoclassical Navier–Stokes Equations Considering the Gyftopoulos–Beretta Exposition of Thermodynamics
    • Janusz Badur
    • Michel Feidt
    • Paweł Ziółkowski
    2020 Full text ENERGIES

    The seminal Navier-Stokes equations were stated even before the creation of the foundations of thermodynamics and its first and second laws. There is a widespread opinion in the literature on thermodynamic cycles that the Navier-Stokes equations cannot be taken as a thermodynamically correct model of a local "working fluid", which would be able to describe the conversion of "heating" into "working" (Carnot's type cycles) and vice versa (Afanasjeva's type cycles). Also, it is overall doubtful that "cycle work is converted into cycle heat" or vice versa. The underlying reason for this situation is that the Navier-Stokes equations come from a time when thermodynamic concepts such as "internal energy" were still poorly understood. Therefore, this paper presents a new exposition of thermodynamically consistent Navier-Stokes equations. Following that line of reasoning-and following Gyftopoulos and Beretta's exposition of thermodynamics-we introduce the basic concepts of thermodynamics such as "heating" and "working" fluxes. We also develop the Gyftopoulos and Beretta approach from 0D into 3D continuum thermodynamics. The central role within our approach is played by "internal energy" and "energy conversion by fluxes." Therefore, the main problem of exposition relates to the internal energy treated here as a form of "energy storage." Within that context, different forms of energy are discussed. In the end, the balance of energy is presented as a sum of internal, kinetic, potential, chemical, electrical, magnetic, and radiation energies in the system. These are compensated by total energy flux composed of working, heating, chemical, electrical, magnetic, and radiation fluxes at the system boundaries. Therefore, the law of energy conservation can be considered to be the most important and superior to any other law of nature. This article develops and presents in detail the neoclassical set of Navier-Stokes equations forming a thermodynamically consistent model. This is followed by a comparison with the definition of entropy (for equilibrium and non-equilibrium states) within the context of available energy as proposed in the Gyftopoulos and Beretta monograph. The article also discusses new possibilities emerging from this "continual" Gyftopoulos-Beretta exposition with special emphasis on those relating to extended irreversible thermodynamics or Van's "universal second law".

  • Nested Kriging Surrogates for Rapid Multi-Objective Optimization of Compact Microwave Components
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    2020 APPLIED COMPUTATIONAL ELECTROMAGNETICS SOCIETY JOURNAL

    A procedure for rapid EM-based multi-objective optimization of compact microwave components is presented. Our methodology employs a recently developed nested kriging modelling to identify the search space region containing the Pareto-optimal designs, and to construct a fast surrogate model. The latter permits determination of the initial Pareto set, further refined using a separate surrogate-assisted process. As an illustration, a three-section impedance transformer is designed for the best matching and minimum size. The set of trade-off designs is produced at the low computational cost of only a few hundred of high-fidelity EM simulations of the transformer circuit despite a large number of its geometry parameters.

  • Nested Kriging with Variable Domain Thickness for Rapid Surrogate Modeling and Design Optimization of Antennas
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    2020 Full text Electronics

    Design of modern antennas faces numerous difficulties, partially rooted in stringent specifications imposed on both electrical and field characteristics, demands concerning various functionalities (circular polarization, pattern diversity, band-notch operation), but also constraints imposed upon the physical size of the radiators. Conducting the design process at the level of full-wave electromagnetic (EM) simulations, otherwise dictated by reliability, entails considerable computational expenses, which is another and a serious challenge. It is especially pronounced for the procedures involving repetitive EM analyses, e.g., parametric optimization. Utilization of fast surrogate models as a way of mitigating this issue has been fostered in the recent literature. Unfortunately, construction of reliable surrogates for antenna structures is hindered by their highly nonlinear responses and even more by the utility requirements: design-ready models are to be valid over wide ranges of operating conditions and geometry parameters. Recently proposed performance-driven modeling, especially the nested kriging framework, addresses these difficulties by confining the surrogate model domain to a region that encapsulates the designs being optimum with respect to the relevant figures of interest. The result is a dramatic reduction of the number of training samples needed to render a usable model. This paper introduces a variable-thickness domain, which is an important advancement over the basic nested kriging. The major benefit demonstrated using two antenna examples is a further and significant (up to seventy percent) reduction of the training data acquisition cost. It is achieved while ensuring that the model domain covers the regions containing optimum designs for various sets of performance specifications.

  • Neural Architecture Search for Skin Lesion Classification
    • Arkadiusz Kwasigroch
    • Michał Grochowski
    • Agnieszka Mikołajczyk
    2020 Full text IEEE Access

    Deep neural networks have achieved great success in many domains. However, successful deployment of such systems is determined by proper manual selection of the neural architecture. This is a tedious and time-consuming process that requires expert knowledge. Different tasks need very different architectures to obtain satisfactory results. The group of methods called the neural architecture search (NAS) helps to find effective architecture in an automated manner. In this paper, we present the use of an architecture search framework to solve the medical task of malignant melanoma detection. Unlike many other methods tested on benchmark datasets, we tested it on practical problem, which differs greatly in terms of difficulty in distinguishing between classes, resolution of images, data balance within the classes, and the number of data available. In order to find a suitable network structure, the hill-climbing search strategy was employed along with network morphism operations to explore the search space. The network morphism operations allow for incremental increases in the network size with the use of the previously trained network. This kind of knowledge reusing allows significantly reducing the computational cost. The proposed approach produces structures that achieve similar results to those provided by manually designed structures, at the same time making use of almost 20 times fewer parameters. What is more, the search process lasts on average only 18h on single GPU.

  • Neural network based algorithm for hand gesture detection in a low-cost microprocessor applications
    • Tomasz Kocejko
    • Filip Brzezinski
    • Jacek Rumiński
    • Artur Poliński
    • Jerzy Wtorek
    2020

    In this paper the simple architecture of neural network for hand gesture classification was presented. The network classifies the previously calculated parameters of EMG signals. The main goal of this project was to develop simple solution that is not computationally complex and can be implemented on microprocessors in low-cost 3D printed prosthetic arms. As the part of conducted research the data set EMG signals corresponding to 5 different gestures was created. The accuracy of elaborated solution was 90% when applied real time on data sampled with 1kHz frequency and 75% when applied real time on data acquired and process directly on microprocessor with lower,100Hz sampling frequency.

  • Neural Network Subgraphs Correlation with Trained Model Accuracy
    • Izajasz Wrosz
    2020

    Neural Architecture Search (NAS) is a computationally demanding process of finding optimal neural network architecture for a given task. Conceptually, NAS comprises applying a search strategy on a predefined search space accompanied by a performance evaluation method. The design of search space alone is expected to substantially impact NAS efficiency. We consider neural networks as graphs and find a correlation between the presence of subgraphs and the network’s final test accuracy by analyzing a dataset of convolutional neural networks trained for image recognition. We also consider a subgraph based network distance measure and suggest opportunities for improved NAS algorithms that could benefit from our observations.

  • New Approaches for Escherichia coli Genotyping
    • Roman Kotłowski
    • Katarzyna Grecka
    • Barbara Kot
    • Piotr Szweda
    2020 Full text Pathogens

    Easy-to-perform, fast, and inexpensive methods of differentiation of Escherichia coli strains beyond the species level are highly required. Herein two new, original tools for genotyping of E. coli isolates are proposed. The first of the developed method, a PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) test uses a highly variable fliC gene, encoding the H antigen as a molecular target. The designing of universal pair of primers and selection of the optimal restriction enzyme RsaI was preceded by in silico comparative analysis of the sequences of the genes coding for 53 different serotypes of H-antigen (E. coli flagellin). The target fragments of E. coli genomes for MLST method were selected on the basis of bioinformatics analysis of complete sequences of 16 genomes of E. coli. Initially, seven molecular targets were proposed (seven pairs of primers) and five of them were found useful for effective genotyping of E. coli strains. Both developed methods revealed high differentiation power, and a high genetic diversity of the strains tested was observed. Within the group of 71 strains tested, 29 and 47 clusters were revealed with fliC RFLP-PCR and MLST methods, respectively. Differentiation of the strains with the reference BOX-PCR method revealed 31 different genotypes. The in silico analysis revealed that the discriminatory power of the new MLST method is comparable to the Pasteur and Achtman schemes and is higher than the discriminatory power of the method developed by Clermont. From the epidemiology point of view, the outcomes of our investigation revealed that in most cases, the patients were infected with unique strains, probably from environmental sources. However, some strains isolated from different patients of the wards of pediatrics, internal medicine, and neurology were classified to the same genotype when the results of all three methods were taken into account. It could suggest that they were transferred between the patients.

  • New Challenges in Management and Economics in 21st century. Selected studies and examples
    • Piotr Grudowski
    • Dariusz Dudek
    • Julita Majczyk
    • Mateusz Muchlado
    2020

    In Chapter 1 authors describe the method used to assess the level of readiness of an organization to introduce the Lean Six Sigma concept supporting the Quality 4.0 assumptions, which is gaining more and more interest not only in large organizations, but also in the SME sector. Its use will be illustrated by the example of a small service company. Chapter 2 presents the characteristics of blockchain technology applications in the modern economy. Particular attention was paid to aspects such as security, staff issues and trust. Chapter 3 deals with the entrepreneurship of immigrants from the Far East. Patterns of approaches leading to strategy choices implemented by the immigrants were presented as well as processes of defining customers and factors influencing the choice between an ethnic and local business, immigrants' approaches to building market position and development. In this diverse way, the authors wanted to indicate how many factors can determine the effectiveness and efficiency of various organizations in the age of Industry 4.0. Only knowledge of management and economics that is wide and open to various challenges will allow executives to successfully face contemporary and future risks.

  • New pathways for functionalization of phosphorus ligands
    • Anna Ordyszewska
    2020

    The presented dissertation consistsof two main partsand focuses on the synthesis and characterization of new low-valent phosphorus compounds. Thesestudies have already been fully described in three JCR-journals. The first partdescribes the utilization ofselectedphosphanylphosphinidene transition metal complexes as a source of diversified phosphorus ligands. For thispurposethree complexes havebeenchosen:[(DippN)2(Cl)W(η2-tBu2P-P)][Li(dme)3], [(pTol3P)2Pt(η2-tBu2P=P)], and [(dppe)Pt(η2-tBu2P=P)]. The reactivity of these complexes toward terminal dihaloalkanes and chalcogens was taken under investigation. As a result, new complexes with a variety of phosphorusmoietiessuch astBu2PP-R (R = Me, I, (CH2)3Br, (CH2)nPPtBu2 (n = 4, 6), PPtBu2 )ortBu2P-P-Se, tBu2P(Se)-P, tBu2P-P-P andtBu2P(S)-P-P-PtBu2were obtained.In the second part a new family of diphosphinoboraneswas synthesized that contain not only phosphorus but also boron atom in the structure. Diphosphinoboranes(R2P)2BR’were formed as a result of the reactions of selected lithium phosphides R2PLi (R2P=tBu2P, Cy2P, Ph2P,tBuPhP) and dibromoboranes R’BBr2(R’ = NiPr2, Ph). Theycan be classified in three different groups depending on their electronic and structural properties. The amino(diphosphino)borane(Ph2P)2BNiPr2has also been proven to actaschelating ligand in the reaction with CODPtMe2.

  • New synthesis route of highly porous InxCo4Sb12 with strongly reduced thermal conductivity
    • N. Gostkowska-Lekner
    • B. Trawinski
    • A. Kosonowski
    • Beata Bochentyn
    • Marcin Lapinski
    • Tadeusz Miruszewski
    • Krzysztof W. Wojciechowski
    • Bogusław Kusz
    2020 Full text JOURNAL OF MATERIALS SCIENCE

    Highly porous, In-filled CoSb3 skutterudite materials with an attractive thermoelectric figure of merit (ZT * 1) and corresponding dense samples were fabricated through the cost-effective method of reduction in oxides in dry hydrogen and the pulsed electric current sintering (PECS) method, respectively. The reduction process was described in detail using in situ thermogravimetric analysis of Co2O3, Sb2O3 and In(NO3)35H2O separately and in a mixture. Two methods to synthesise the same material were examined: (a) free sintering of an initially reduced powder and (b) PECS. The free-sintered materials with higher porosities (up to * 40%) exhibited lower values of electrical conductivity than the dense PECS samples (porosity up to * 5%), but the benefit of an even sixfold reduction in thermal conductivity resulted in higher ZT values. The theoretical values of thermal conductivity for various effective media models considering randomly oriented spheroid pores are in good agreement with the experimental thermal conductivity data. The assumed distribution and shape of the pores correlated well with the scanning electron microscope analysis of the microstructure. The lowest value of thermal conductivity, equal to 0.5 W/m K, was measured at 523 K for In0.1Co4Sb12 with 41% porosity. The highest value of ZT max = 1.0 at 673 K was found for the In0.2Co4Sb12 sample in which the porosity was 36%

  • New Unsymmetrical Bisacridine Derivatives Noncovalently Attached to Quaternary Quantum Dots Improve Cancer Therapy by Enhancing Cytotoxicity toward Cancer Cells and Protecting Normal Cells
    • Joanna Pilch
    • Edyta Matysiak-Brynda
    • Agata Kowalczyk
    • Piotr Bujak
    • Zofia Mazerska
    • Anna M. Nowicka
    • Ewa Augustin
    2020 ACS Applied Materials & Interfaces

    The use of nanoparticles for the controlled drug delivery to cells has emerged as a good alternative to traditional systemic delivery. Quantum dots (QDs) offer potentially invaluable societal benefits such as drug targeting and in vivo biomedical imaging. In contrast, QDs may also pose risks to human health and the environment under certain conditions. Here, we demonstrated that unique combination of nanocrystals core components (Ag-In-Zn-S) would eliminate the toxicity problem and increases their biomedical applications. The alloyed quaternary nanocrystals Ag-In-Zn-S (QDgreen: Ag1.0In1.2Zn5.6S9.4 and QDred: Ag1.0In1.0Zn1.0S3.5) were used to transport new unsymmetrical bisacridine derivatives (UAs: C-2028 and C-2045) into lung H460 and colon HCT116 cancer cells for improving the cytotoxic and antitumor action of these compounds. UAs were coupled with QD through physical adsorption. The obtained results clearly indicate that the synthesized nanoconjugates exhibited higher cytotoxic activity than unbound compounds, especially towards lung H460 cancer cells. Importantly, unsymmetrical bisacridines non-covalently attached to QD strongly protect normal cells from the drug action. It is worth to point out that QDgreen or QDred without UAs did not influence the growth of cancer as well as normal cells what is consistent with in vivo results. In non-cellular systems, at pH 5.5 and 4.0, which relates to the conditions of endosomes and lysosomes, the UAs released from QD-UAs nanoconjugates. An increase of total lysosomes content was observed in H460 cells treated with QDs-UAs what can affect the release of the UAs from the conjugates. Moreover, confocal laser scanning microscopy analyses revealed that QD-UAs nanoconjugates enter to H460 cells more efficiently than to HCT116 and normal cells, which may be the reason of their higher cytotoxicity against lung cancer. Summarizing, the non-covalent attachment of UAs to QDs increases the therapeutic efficiency of UAs, by improving cytotoxicity toward lung H460 cancer cells and having protecting effects on normal cells.

  • New uranium(vi) and isothiouronium complexes: synthesis, crystal structure, spectroscopic characterization and a DFT study
    • Ewelina Grabias
    • Bogdan Tarasiuk
    • Anna Dołęga
    • Marek Majdan
    2020 CRYSTENGCOMM

    The crystal structures of S,S′-2,5-dimethylbenzene-1,4-diylbis(methylisothiouronium) diacetate (1_ac), S,S′-2,5-dimethylbenzene-1,4-diylbis(methylisothiouronium) dichloride (1_Cl), 1_U complex, S,S′-naphthalene-1,4-diylbis(methylisothiouronium) dichloride (2_Cl), and 2_U complex were determined for the first time. The supramolecular structures of the compounds obtained are mainly based on hydrogen bonding and ionic interactions between the isothiouronium cations and the counter anions Cl−, CH3COO−, and [UO2(CH3COO)3]−. Their structural and spectroscopic properties were studied, and the results of DFT calculations were compared with the experimental findings to provide insights into the properties of these new compounds. The DFT calculations indicate a strong preference for the formation of the outer-sphere complex (ion-pair) between the uranyl species and an isothiouronium cation, and very large stabilization energies of the interactions, which can be utilized for the selective binding of U(VI). The compounds obtained are the first f-element and isothiouronium salt complexes described so far.

  • Newton’s Method for the McKendrick-von Foerster Equation
    • Agnieszka Bartłomiejczyk
    • Monika Wrzosek
    2020

    In the paper we study an age-structured model which describes the dynamics of one population with growth, reproduction and mortality rates. We apply Newton’smethod to the McKendrick-von Foerster equation in the semigroup setting. We prove its first- and second-order convergence.

  • Ni/cerium Molybdenum Oxide Hydrate Microflakes Composite Coatings Electrodeposited from Choline Chloride: Ethylene Glycol Deep Eutectic Solvent
    • Juliusz Winiarski
    • Anna Niciejewska
    • Jacek Ryl
    • Kazimierz Darowicki
    • Sylwia Baśladyńska
    • Katarzyna Winiarska
    • Bogdan Szczygieł
    2020 Full text Materials

    Cerium molybdenum oxide hydrate microflakes are codeposited with nickel from a deep eutectic solvent-based bath. During seven days of exposure in 0.05 M NaCl solution, the corrosion resistance of composite coating (Ni/CeMoOxide) is slightly reduced, due to the existence of some microcracks caused by large microflakes. Multielemental analysis of the solution, in which coatings are exposed and the qualitative changes in the surface chemistry (XPS) show selective etching molybdenum from microflakes. The amount of various molybdenum species within the surface of coating nearly completely disappear, due to the corrosion process. Significant amounts of Ce3+ compounds are removed, however the corrosion process is less selective towards the cerium, and the overall cerium chemistry remains unchanged. Initially, blank Ni coatings are covered by NiO and Ni(OH)2 in an atomic ratio of 1:2. After exposure, the amount of Ni(OH)2 increases in relation to NiO (ratio 1:3). For the composite coating, the atomic ratios of both forms of nickel vary from 1:0.8 to 1:1.3. Despite achieving lower corrosion resistance of the composite coating, the applied concept of using micro-flakes, whose skeleton is a system of Ce(III) species and active form are molybdate ions, may be interesting for applications in materials with potential self-healing properties.

  • Nieniszczące badania stalowych konstrukcji obiektów budowlanych
    • Dariusz Kowalski
    2020

    W miarę powszechne jest wykonywanie badań nieniszczących w zakresie wytwarzania elementów i obiektów o konstrukcji stalowych. Wynika to z potrzeby właściwego kontrolowania materiału stalowego poddawanego przetwarzaniu i łączeniu za pomocą technik spawalniczych. Badania nieniszczące związane są też z wykonywaniem zabezpieczeń antykorozyjnych, które chronią nasz materiał przed jego przyspieszoną degradacją w warunkach jakim przychodzi nam eksploatować konstrukcje stalowe. Badania materiału, połączeń spawanych, całych konstrukcji czy też powłok antykorozyjnych wykonywane są przede wszystkim w fazie wytwarzania, montażu i odbioru. Nader często w życiu inżynierskim przychodzi nam te same techniki badawcze stosować w sposób kompleksowy czy też wybiórczy do badania obiektów już eksploatowanych, które albo uległy awariom, zniszczeniom lub też nastąpiła ich degradacja, zużycie eksploatacyjne czy też korozyjne lub występują w nich określone problemy eksploatacyjne, np. drgania konstrukcji. Nie sposób, w niniejszym materiale, przedstawić wszystkie badania które są możliwe do wykonania w ramach produkcji materiału, wytwarzania konstrukcji czy też ich zabezpieczania dlatego, że czynniki i potrzeby tych badań są bardzo różne, tak jak różne metody możemy do tych działań zastosować. W badaniach obiektów lub ich określonych części często stosujemy nieznormalizowane, metody innowacyjne. W materiale niniejszym przedstawiono podstawowe wymagania normowe oraz badania odbiorowe w zakresie wytwarzania konstrukcji stalowych spawanych oraz badania z zakresu powłok.

  • Nietypowa podziemna konstrukcja oporowa w technologii DSM jako zabezpieczenie głębokiej wymiany gruntu
    • Grzegorz Horodecki
    2020

    W artykule przedstawiono nietypowe rozwiązanie podparcia i zabezpieczenia głębokiej wymiany gruntu z zastosowaniem przestrzennej konstrukcji oporowej w technologii DSM, ze względu na ograniczenie miejsca oraz zapewnienie stateczności nasypu drogowego. Opisano również realizację rozwiązania oraz prowadzony monitoring geotechniczny.

  • Nikola Tesla i jego wynalazki
    • Dariusz Świsulski
    2020 Wiadomości Elektrotechniczne

    Przedstawiono biografię Nikoli Tesli. Omówiono dziedziny, którymi się zajmował i opisano najważniejsze wynalazki.

  • Nitrogen removal in vertical flow constructed wetlands: influence of bed depth and high nitrogen loadings
    • Adelaide Almeida
    • Krzysztof Jóźwiakowski
    • Alina Kowalczyk-Juśko
    • Piotr Bugajski
    • Karolina Kurek
    • Fátima Carvalho
    • Anabela Durao
    • Carlos Ribeiro
    • Magdalena Gajewska
    2020 ENVIRONMENTAL TECHNOLOGY

    The aim of the study was to evaluate the nitrogen removal and its effects on the plant’s growth and leaves morphology. using two subsurface vertical flow (VF bed), with different depths (0.24 m2 × 0.70 m; 0.24 m2 × 0.35 m) and nitrogen load increments. The VF bed were planted with Vetiveria zizanioides, filled with light expanded clay aggregates (Leca®NR 10/20) and fed in parallel mode with synthetic wastewater. High ammonium nitrogen concentration ([NH4+–N] from 68 ± 3 to 290 ± 8 mg L−1) was used without toxicity symptoms in plants, although the effects of ammonium nitrogen load were stopped the growth of the plants. Significant differences between ammonium nitrogen removed in each VF bed obtained for total nitrogen (TNinfl.) ≥ 27 ± 0.8 g m−2 d−1. The nitrification was contributed to ammonium nitrogen removal because was found higher values of nitrate and nitrite in the effluent. These values were more higher in VF bed 1 than in the VF bed 2, since ammonium nitrogen removal were also more higher in VF bed 1 than in the VF bed 2. Total nitrogen mass balance was carried out and the results show that the nitrification/denitrification process occurred with nitrogen plants uptake. It was observed that the VF bed depth has an influence on all nitrogen removal processes. As higher the depth root system it is seemed to favour the creation of zones with different oxidations conditions that allow the nitrogen compounds to be removed intensively.

  • NLP Questions Answering Using DBpedia and YAGO
    • Tomasz Boiński
    • Julian Szymański
    • Bartłomiej Dudek
    • Paweł Zalewski
    • Szymon Dompke
    • Maria Czarnecka
    2020 Full text Vietnam Journal of Computer Science

    In this paper, we present results of employing DBpedia and YAGO as lexical databases for answering questions formulated in the natural language. The proposed solution has been evaluated for answering class 1 and class 2 questions (out of 5 classes defined by Moldovan for TREC conference). Our method uses dependency trees generated from the user query. The trees are browsed for paths leading from the root of the tree to the question subject. We call those paths fibers and they represent the user intention. The question analysis consists of three stages: query analysis, query breakdown and information retrieval. The aim of those stages is the detection of the entities of interest and its attributes, indicating the users’ domain of interest. The user query is then converted into a SPARQL query and sent to the DBpedia and YAGO databases. The baseline and the extended methods are presented and the quality of the solution is evaluated and discussed.

  • Nonadaptive estimation of the rotor speed in an adaptive full order observer of induction machine
    • Marcin Morawiec
    • Paweł Kroplewski
    2020 Full text Bulletin of the Polish Academy of Sciences-Technical Sciences

    The article proposes a new method of reproducing the angular speed of the rotor of a cage induction machine designed for speed observers based on the adaptive method. In the proposed solution, the value of the angular speed of the rotor is not determined by the classical law of adaptation using the integrator only by an algebraic relationship. Theoretical considerations were confirmed by simulation and experimental tests.

  • Non-compulsory practical education programme for modernist heritage
    • Anna Orchowska-Smolińska
    2020 Full text World Transactions on Engineering and Technology Education

    A non-compulsory programme for students of architecture that contains more specialised topics beyond the basic subjects is an important educational tool. The advantages include classes in smaller groups, the possibility of practical exercises in real field conditions and the benefits of meeting professional practitioners. This type of programme is particularly useful for teaching architectural heritage of the 20th Century, its protection and conservation; this knowledge is not widespread. The topic is current and there have been numerous developments over the years. The aims outlined in this article are to present the scope of this non-compulsory programme, including the interactive field classes, workshops and summer school. The benefits of this practically oriented programme are confirmed by the results achieved.

  • Non-Destructive Testing of the Longest Span Soil-Steel Bridge in Europe—Field Measurements and FEM Calculations
    • Mikołaj Miśkiewicz
    • Bartosz Sobczyk
    • Paweł Tysiąc
    2020 Full text Materials

    The article describes interdisciplinary and comprehensive non-destructive diagnostic tests of final bridge inspection and acceptance proposed for a soil-steel bridge made of corrugated sheets, being the European span length record holder (25.74 m). As an effect of an original concept a detailed and precise information about the structure short-term response was collected. Periodic diagnostics of bridge deformations was done one year after it was built. Load test design was based on numerical simulations performed by means of finite element method (FEM). In situ measurements were done with the aid of: inductive sensors, optical total station, and terrestrial laser scanner. The results produced by terrestrial laser scanning were used to build a precise image of structure deformation in 3D space during the tests. The accuracy of laser mapping was significantly increased using the information coming from total station and inductive sensors. These have higher accuracy and therefore can be used as reference. Thus, new quality in measurements is introduced. Good correspondence between in situ values and FEM estimations was achieved. Therefore, such a combination of testing methods can be used in non-destructive diagnostics of structures and is an interesting alternative for the standard approach, in which the measurements are done in limited number of points.

  • Nondestructive Testing of the Miter Gates Using Various Measurement Methods
    • Mikołaj Binczyk
    • Przemysław Kalitowski
    • Jakub Szulwic
    • Paweł Tysiąc
    2020 Full text SENSORS

    When any problems related to civil engineering structures appear, identifying the issue through the usage of only one measuring method is difficult. Therefore, comprehensive tests are required to identify the main source. The strains and displacement measurements, as well as modal identification, are widely used in the nondestructive testing of structures. However, measurements are usually carried out at several points and confirm or exclude only one of many potential causes of the problem. The main aim of this paper is to identify the causes of miter gates’ excessive vibration. The research includes displacement measurements using a tachometer and a laser scanner, acceleration measurements connected with modal analysis, and calculations with the finite element method (FEM) model. The numerical model underwent verification regarding test results. Particular attention was paid to evaluate the practical use of a laser scanner for diagnosing miter gates. Unlike classical methods, it measures many points. The analysis eliminated a number of potential causes of excessive vibration and highlighted the field of excessive deformation. The identified anomaly could be associated with bearings’ misalignment after closing the door. This construction part should be subjected to further research using classical methods. The laser scanning has been proven to be a method that can only generally present the deformation of the structure.

  • Non-Diophantine Arithmetics in Mathematics, Physics and Psychology
    • Mark Burgin
    • Marek Czachor
    2020

    For a long time, all thought there was only one geometry — Euclidean geometry. Nevertheless, in the 19th century, many non-Euclidean geometries were discovered. It took almost two millennia to do this. This was the major mathematical discovery and advancement of the 19th century, which changed understanding of mathematics and the work of mathematicians providing innovative insights and tools for mathematical research and applications of mathematics. A similar event happened in arithmetic in the 20th century. Even longer than with geometry, all thought there was only one conventional arithmetic of natural numbers — the Diophantine arithmetic, in which 2+2=4 and 1+1=2. It is natural to call the conventional arithmetic by the name Diophantine arithmetic due to the important contributions to arithmetic by Diophantus. Nevertheless, in the 20th century, many non-Diophantine arithmetics were discovered, in some of which 2+2=5 or 1+1=3. It took more than two millennia to do this. This discovery has even more implications than the discovery of new geometries because all people use arithmetic. This book provides a detailed exposition of the theory of non-Diophantine arithmetics and its various applications. Reading this book, the reader will see that on the one hand, non-Diophantine arithmetics continue the ancient tradition of operating with numbers while on the other hand, they introduce extremely original and innovative ideas.

  • Nonlinear dynamic analysis of the pure “buckling” mechanism during blow-out trauma of the human orbit
    • Marcin Zmuda Trzebiatowski
    • Paweł Kłosowski
    • Andrzej Skorek
    • Krzysztof Żerdzicki
    • Paweł Lemski
    • Mateusz Koberda
    2020 Full text Scientific Reports

    Considering the interplay between orbital bones and intraorbital soft tissues, commonly accepted patterns of the blow-out type of trauma within the human orbit require more thorough investigation to assess the minimal health-threatening impact value. Two different three-dimensional finite element method (FEM) models of the human orbital region were developed to simulate the pure “buckling” mechanism of orbital wall fracture in two variants: the model of orbital bone elements and the model of orbital bone, orbit and intraorbital tissue elements. The mechanical properties of the so-defined numerical skull fragment were applied to the model according to the unique laboratory tensile stress tests performed on small and fragile specimens of orbital bones as well as using the data available in the literature. The nonlinear transient analysis of the contact problem between bodies that differ substantially in terms of the Young’s modulus was carried out to investigate the interaction of different bodies within an instant injury. Potential damage areas were found within the lower orbital wall as well as the destructive load values for both FEM skull models (7,660 N and 8,520 N). Moreover, numerical simulations were validated by comparing them with computed tomography scans of real injuries.

  • Non-Linear Interaction of Harmonic Waves in a Quasi-Isentropic Flow of Magnetic Gas
    • Anna Perelomova
    2020 Full text Archives of Acoustics

    The diversity of wave modes in the magnetic gas gives rise to a wide variety of nonlinear phenomenaassociated with these modes. We focus on the planar fast and slow magnetosound waves in the geometryof a flow where the wave vector forms an arbitrary angleθwith the equilibrium straight magnetic field.Nonlinear distortions of a modulated signal in the magnetic gas are considered and compared to thatin unmagnetised gas. The case of acoustical activity of a plasma is included into consideration. Theresonant three-wave non-collinear interactions are also discussed. The results depend on the degree ofnon-adiabaticity of a flow,θ, and plasma-β.

  • Nonlinear numerical simulation of earthquake-induced pounding between timber frame buildings
    • Wojciech Migda
    • Marcin Szczepański
    • Natalia Lasowicz
    • Anna Jakubczyk-Gałczyńska
    • Robert Jankowski
    2020 AIP Conference Proceedings

    Earthquakes may induce serious dynamic loads acting on buildings, which can lead to damage or even destruction of the whole structure. In densely populated areas, it is quite common that buildings are located very close one to another which can result in pounding between them during ground motions. Due to the environmental awareness, multi-story timber frame buildings are gaining popularity and therefore there is a need to investigate the effects of structural collisions on seismic response of such buildings. In this paper, the results of advanced numerical FEM simulation, focused on inter-story pounding between two adjacent multi-story timber frame buildings, are presented. The results of the study show that structural interactions have a significant influence on the overall response of buildings exposed to damaging seismic excitations. Moreover, due to deformability of buildings made of wood, pounding may change response of such buildings much more, as compared to steel, reinforced concrete or masonry structures. Finally, the results confirm that the use of the nonlinear FEM with detailed representation of material and geometric structural properties can be considered as the effective approach in obtaining the accurate response of colliding timber frame buildings during earthquakes

  • Nonlocal Vibration of Carbon/Boron-Nitride Nano-hetero-structure in Thermal and Magnetic Fields by means of Nonlinear Finite Element Method
    • Hamid M. Sedighi
    • Mohammad Malikan
    • Ali Valipour
    • Krzysztof Kamil Żur
    2020 Full text Journal of Machinery Manufacture and Reliability

    Hybrid nanotubes composed of carbon and boron-nitride nanotubes have manifested as innovative building blocks to exploit the exceptional features of both structures simultaneously. On the other hand, by mixing with other types of materials, the fabrication of relatively large nanotubes would be feasible in the case of macroscale applications. In the current article, a nonlinear finite element formulation is employed to deal with the nonlocal vibrational behavior of carbon/boron-nitride nano-hetero-tubes in the presence of magneto-thermal environment. Euler-Bernoulli beam model in conjunction with the Eringen's nonlocal theory of elasticity is adopted to derive the governing equation of motion. In order to conduct a nonlinear frequency analysis, the von-Kármán nonlinearity associated with moderate rotations is also considered. It is well-known that temperature gradients can significantly change the dynamic behavior of nanotubes. On the other hand, the coefficients of thermal expansions of carbon and boron-nitride nanotubes are quite different which may affect the structural stability of hybrid nanotubes. Hence, to explore the vibration characteristic of such composite structures, the influence of magneto-thermal environment is also taken into account. Finally, the eigenvalue analysis is performed to exhibit the nonlinear mode shapes and natural frequencies of the system due to initial displacement. It is expected that the recognition of dynamic behavior of such hybrid nanotubes may open the doors to the creative design of next-generation nanodevices.

  • Nonreciprocal cavities and the time-bandwidth limit: comment
    • Kosmas L. Tsakmakidis
    • Yun You
    • Tomasz Stefański
    • Linfang Shen
    2020 Full text Optica

    In their paper in Optica 6, 104 (2019), Mann et al. claim that linear, time-invariant nonreciprocal structures cannot overcome the time-bandwidth limit and do not exhibit an advantage over their reciprocal counterparts, specifically with regard to their time-bandwidth performance. In this Comment, we argue that these conclusions are unfounded. On the basis of both rigorous full-wave simulations and insightful physical justifications, we explain that the temporal coupled-mode theory, on which Mann et al. base their main conclusions, is not suited for the study of nonreciprocal trapped states, and instead direct numerical solutions of Maxwell’s equations are required. Based on such an analysis, we show that a nonreciprocal terminated waveguide, resulting in a trapped state, clearly outperforms its reciprocal counterpart; i.e., both the extraordinary time-bandwidth performance and the large field enhancements observed in such modes are a direct consequence of nonreciprocity.

  • Non-Salient Brushless Synchronous Generator Main Exciter Design for More Electric Aircraft
    • Filip Kutt
    • Michał Michna
    • Grzegorz Kostro
    2020 Full text ENERGIES

    This paper presents a prototype of high speed brushless synchronous generators (BSG) design for the application in autonomous electric power generation systems (e.g., airplane power grid). Commonly used salient pole field of the main generator part of BSG was replaced with a prototype non-salient pole field. The main objective of the research is an investigation into the advantages and disadvantages of a cylindrical field of the main generator part of BSG over the original salient pole field. The design process of the prototype generator is presented with a focus on the electromagnetic and mechanical finite element method (FEM) analysis. The measurements of prototype and commercial BSG were conducted for the nominal speed of 8 krpm. The advantages and disadvantages of the proposed solution were established based on measurements in load and no-load conditions.

  • Non-standard contact conditions in generalized continua: microblock contact model for a Cosserat body
    • Maciej Lewandowski-Szewczyk
    • S. Stupkiewicz
    2020 Full text INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES

    Generalized continuum theories involve non-standard boundary conditions that are associated with the additional kinematic variables introduced in those theories, e.g., higher gradients of the displacement field or additional kinematic degrees of freedom. Accordingly, formulation of a contact problem for such a continuum necessarily requires that adequate contact conditions are formulated for the additional kinematic variables and/or for the respective generalized tractions. In this paper, we address several related open problems, namely, how to enhance the classic contact conditions to include the effects of the additional kinematic variables, how to link the enhanced contact model to the underlying microstructure of the solid, and how to do it in a consistent manner. As a first step towards a new class of contact models for generalized continua, a microblock contact model is derived for a Cosserat solid based on simple micromechanical considerations. To illustrate the non-trivial effects introduced by the non-standard boundary conditions, the problem of compression of an infinite strip with nonaligned microblocks is considered, and the analytical solution is derived for the corresponding boundary layers. A Hertz-like contact problem is also solved numerically with the focus on non-standard features of the solution and on the related size effects.

  • Normy i szkolenia z normalizacji w Bibliotece PG
    • Janusz Waluszko
    2020 Pismo PG

    Tekst omawia znaczenie norm dla studentów i naukowców oraz szkolenia z normalizacji organizowane przez Bibliotekę Politechniki Gdańskiej

  • Novel 1,2,4-Oxadiazole Derivatives in Drug Discovery
    • Karol Biernacki
    • Mateusz Daśko
    • Olga Ciupak
    • Konrad Kubiński
    • Janusz Rachoń
    • Sebastian Demkowicz
    2020 Full text Pharmaceuticals

    Abstract: Five-membered 1,2,4-oxadiazole heterocyclic ring has received considerable attention because of its unique bioisosteric properties and an unusually wide spectrum of biological activities. Thus, it is a perfect framework for the novel drug development. After a century since the 1,2,4-oxadiazole have been discovered, the uncommon potential attracted medicinal chemists’ attention, leading to the discovery of a few presently accessible drugs containing 1,2,4-oxadiazole unit. It is worth noting that the interest in a 1,2,4-oxadiazoles’ biological application has been doubled in the last fifteen years. Herein, after a concise historical introduction, we present a comprehensive overview of the recent achievements in the synthesis of 1,2,4-oxadiazole-based compounds and the major advances in their biological applications in the period of the last five years as well as brief remarks on prospects for further development.

  • Novel ABTS-dot-blot method for the assessment of antioxidant properties of food packaging
    • Barbara Kusznierewicz
    • Hanna Staroszczyk
    • Edyta Malinowska-Pańczyk
    • Karol Parchem
    • Agnieszka Bartoszek-Pączkowska
    2020 Full text Food Packaging and Shelf Life

    The new ABTS-dot-blot method for the direct determination of antioxidant activity of active packaging that is in contact with foodstuffs has been developed. The usefulness of the new method was verified with the use of agarose, pork gelatin, bacterial cellulose and cellulose-chitosan films with incorporated standard antioxidant – Trolox or plant phytochemicals derived from three types of berry juices (chokeberry, blue-berried honeysuckle, rowanberry) or green tea. The plant components used for preparation of films were characterized by antioxidant profiling with the use of HPLC coupled with post-column derivatization with ABTS. The most abundant antioxidants were polyphenols, mainly anthocyanins, hydroxycinnamates and flavan-3-ols. The antioxidant properties of different types of films studied were evaluated by typical cuvette spectrophotometric ABTS test or by the novel method employing ABTS radical stabilised in an agarose gel. The results obtained for the Trolox containing films showed quantitative linear relationship between antioxidant content and the degree of ABTS bleaching in agarose gel. The results of both standard spectrophotometric method as well as ABTS-dot-blot approach indicated that gelatin, bacterial cellulose and chitosan on their own possessed antioxidant activity, which was substantially increased (6–10 times) by the addition of phytochemicals during film preparation. The highest antioxidant activity was observed for microbial cellulose films, which were prepared on the basis of material obtained during the kombucha drink production.

  • Novel application of dynamic electrochemical impedance monitoring to a cataphoretic coating process
    • Kazimierz Darowicki
    • Paweł Ślepski
    • Michał Szociński
    2020 Full text PROGRESS IN ORGANIC COATINGS

    The paper presents a novel method of on-line impedance monitoring of cataphoretic coating application process. Utilization of dynamic electrochemical impedance spectroscopy (DEIS) overcame the fundamental problem connected with non-stationarity of the aforementioned coating deposition process, which eliminates classical impedance spectroscopy technique from a real-time description of cataphoresis. The paper illustrates selected examples of potentialities of DEIS regarding the characterization of the cataphoretic coating process. Acquired instantaneous impedance spectra enabled on-line insight into impedance changes upon steel substrate polarization duration, thus visualizing coating application progress. DEIS allowed estimation of the time necessary for the coating/steel substrate system to achieve a steady state after polarization switch off. The proposed approach seems to be a step towards real-time monitoring of electrophoretic coating application and offers a potential for improved process control and optimization.

  • Novel approach to interference analysis of glucose sensing materials coated with Nafion
    • Adrian Olejnik
    • Jakub Karczewski
    • Anna Dołęga
    • Katarzyna Siuzdak
    • Katarzyna Grochowska
    2020 BIOELECTROCHEMISTRY

    A gold-based sensing platform, TiND | AuNP | Nafion, was prepared as an exemplary electrode material exhibiting a response to glucose in a neutral solution. The change of electrochemical properties after exposure to glucose and interference compounds such as vitamin C, glycine, urea, paracetamol and acetylsalicylic acid was tested.

  • Novel Class of Proton Conducting Materials—High Entropy Oxides
    • Maria Gazda
    • Tadeusz Miruszewski
    • Daniel Jaworski
    • Aleksandra Dorota Mielewczyk-Gryń
    • Wojciech Skubida
    • Sebastian Lech Wachowski
    • Piotr Winiarz
    • Kacper Dzierzgowski
    • Marcin Stanisław Łapiński
    • Iga Szpunar
    • Ewa Dzik
    2020 Full text ACS Materials Letters

    Here, for the first time, we present data on proton conductivity of high-entropy, single-phase perovskites. The BaZr0.2Sn0.2Ti0.2Hf0.2Ce0.2O3−δ, BaZr0.2Sn0.2Ti0.2Hf0.2Y0.2O3−δ, BaZr1/7Sn1/7Ti1/7Hf1/7Ce1/7Nb1/7Y1/7O3−δ, and BaZr0.15Sn0.15Ti0.15Hf0.15Ce0.15Nb0.15Y0.10O3−δ single-phase perovskites were synthesized. Before electrical measurements, materials were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The following experimental results demonstrated that studied high-entropy perovskites are proton conductors: (1) The observed mass increase upon the switch from dry to wet atmosphere confirmed the water incorporation into materials structure. (2) The electrochemical impedance spectroscopy (EIS) revealed that the total conductivity increased while its activation energy decreased in the presence of water vapor in the atmosphere. (3) The conductivity in atmosphere humidified with H2O and D2O differed one from another, showing typical of proton conductors isotope effect in high-entropy oxides.

  • Novel Fault Identification for Electromechanical Systems via Spectral Technique and Electrical Data Processing
    • Tomasz Ciszewski
    • Len Gelman
    • Andrew Ball
    2020 Full text Electronics

    It is proposed, developed, investigated, and validated by experiments and modelling for the first time in worldwide terms new data processing technologies, higher order spectral multiple correlation technologies for fault identification for electromechanical systems via electrical data processing. Investigation of the higher order spectral triple correlation technology via modelling has shown that the proposed data processing technology effectively detects component faults. The higher order spectral triple correlation technology successfully applied for rolling bearing fault identification. Experimental investigation of the technology has shown, that the technology effectively identifies rolling bearing fault by electrical data processing at very early stage of fault development. Novel technology comparisons via modelling and experiments of the proposed higher order spectral triple correlation technology and the higher order spectra technology show the higher fault identification effectiveness of the proposed technology over the bicoherence technology.

  • Novel MNZ-type microwave sensor for testing magnetodielectric materials
    • Abhishek Jha
    • Nicolò Delmonte
    • Adam Lamęcki
    • Michał Mrozowski
    • Maurizzio Bozzi
    2020 Full text Scientific Reports

    A novel microwave sensor with the mu-near-zero (MNZ) property is proposed for testing magnetodielectric material at 4.5 GHz. The sensor has a double-layer design consisting of a microstrip line and a metal strip with vias on layers 1 and 2, respectively. The proposed sensor can detect a unit change in relative permittivity and relative permeability with a difference in the operating frequency of 45 MHz and 78 MHz, respectively. The MNZ sensor is fabricated and assembled on two layers of Taconic RF-35 substrate, with thicknesses of 0.51 mm and 1.52 mm, respectively, for the measurement of the sample under test using a vector network analyzer. The dielectric and magnetic properties of two standard dielectric materials (Taconic CER-10 and Rogers TMM13i) and of yttrium–gadolinium iron garnet are measured at microwave frequencies. The results are found to be in good agreement with the values available in the literature, which shows the applicability of the prototype for sensing of magnetodielectric materials.

  • Novel N-(aryl/heteroaryl)-2-chlorobenzenesulfonamide derivatives: synthesis and anticancer activity evaluation
    • Anita Bułakowska
    • Jarosław Sławiński
    • Kamila Siedlecka-Kroplewska
    • Grzegorz Stasiłojć
    • Marcin Serocki
    • Mateusz Heldt
    2020 BIOORGANIC CHEMISTRY

    A new series of N-(aryl/heteroaryl)-2-chlorobenzenesulfonamide derivatives 4-21 have been synthesized, and evaluated at the National Cancer Institute (USA) for their in vitro activities against a panel of 60 different human cancer cell lines. Among them, compounds 16, 20 and 21 exhibited remarkable cytotoxic activity against numerous human cancer cell lines. We found that sulfonamide derivative 21 appeared to be more selective than compounds 16 and 20. In comparison to compounds 16 and 20 it showed higher cytotoxic activity against A549 non-small cell lung adenocarcinoma and HCT-116 colon carcinoma cells and was less toxic to HEK-293 human embryonic kidney cells and HaCaT immortalized human keratinocytes. Treatment of A549 and HCT-116 cells with compound 21 resulted in the G0/G1-cell cycle arrest with a concomitant increase in p53 and p21 protein levels. Moreover, compound 21 led to ATP depletion and disruption of the mitochondrial membrane potential in both studied cell lines. Our results suggest that 2,4-dichloro-N-(quinolin-8-yl and/or 1H-indazol-7-yl)benzenesulfonamides serve as novel promising anticancer agents.

  • Novel tetrahedral cobalt(II) silanethiolates: structures and magnetism
    • Daria Kowalkowska-Zedler
    • Natalia Nedelko
    • Katarzyna Kazimierczuk
    • Pavlo Aleshkevych
    • Renata Łyszczek
    • Anna Ślawska-waniewska
    • Agnieszka Pladzyk
    2020 Full text RSC Advances

    Three heteroleptic complexes of Co(II) tri-tert-butoxysilanethiolates have been synthesized with piperidine [Co{SSi(OtBu)3}2(ppd)2] 1, piperazine [Co{SSi(OtBu)3}2(NH3)]2(μ-ppz)·2CH3CN 2, and N-ethylimidazole [Co{SSi(OtBu)3}2(etim)2] 3. The complexes have been characterized by a single-crystal X-ray, revealing their tetrahedral geometry on Co(II) coordinated by two nitrogen and two sulfur atoms. Complexes 1 and 3 are mononuclear, whereas 2 is binuclear. The spectral properties and thermal properties of 1–3 complexes were established by FTIR spectroscopy for solid samples and TGA. The magnetic properties of complexes 1, 2, and 3 have been investigated by static magnetic measurements and X-band EPR spectroscopy. These studies have shown that 1 and 3, regardless of the similarity in structure of CoN2S2 cores, demonstrate different types of local magnetic anisotropy. Magnetic investigations of 2 reveal the presence of weak antiferromagnetic intra-molecular Co(II)–Co(II) interactions that are strongly influenced by the local magnetic anisotropy of individual Co(II) ions.

  • Nowa koncepcja płaszczowo-rurowego wymiennika ciepła z techniką strugową w rurach pęku
    • Jan Wajs
    • Roksana Bochniak
    2020

    W pracy przedstawiono nowe podejście do implementacji techniki strugowej w wymiennikach cylindrycznych. Obiektem badań jest opatentowana konstrukcja płaszczowo-rurowego wymiennika ciepła z techniką strugową obecną w rurach pęku. Generatorem strug są perforowane wkłady rurowe, w których średnica pojedynczego otworu wynosi 1.3 mm. Dla poprawy kompaktowości tego wymiennika, perforowane wkłady wykonano w technologii minikanałowej – ich średnica wewnętrzna wynosi 2 mm. Omówiono budowę i zasadę działania wymiennika, przedstawiono stanowisko pomiarowe do prowadzenia badań cieplno-przepływowych oraz omówiono wyniki wstępnych badań konwekcji jednofazowej w układzie gaz-ciecz. Wyniki te posłużyły do weryfikacji korelacji dostępnych w literaturze przedmiotu.

  • Nowoczesne metody termografii w systemie monitorowania stanu sieci przesyłowych
    • Filip Ratkowski
    • Krzysztof Szuchnik
    2020 Wiadomości Elektrotechniczne

    W artykule przedstawiono obecnie stosowane metody inspekcji termowizyjnej, skupiając się na prewencyjnej diagnostyce stanu sieci przesyłowej. Badanie termowizyjne ma różne wymiary wpływu na efektywność energetyczną. Z jednej strony wykorzystuje się ją do inspekcji szczelności termoizolacji budynków, wpływając na świadomość, że „najtańsza energia to ta zaoszczędzona”, z drugiej strony jest narzędziem dla operatorów sieci dystrybucyjnych i przesyłowych, zmniejszając prawdopodobieństwo zawodności elementów infrastruktury elektroenergetycznej. Przy zwiększającym się sektorze usług inspekcji termowizyjnych, wywołanym dostępnością kamer termowizyjnych i możliwości z nimi związanymi, takimi jak: termowizyjny skaning laserowy, kolejnym krokiem jest implementacja danych o stanie temperatury obiektu w cyklu życia obiektu w BIM i CMS.

  • Nuclear Magnetic Resonance Metabolomics Reveals Qualitative and Quantitative Differences in the Composition of Human Breast Milk and Milk Formulas
    • Dorota Garwolińska
    • Weronika Hewelt-Belka
    • Agata Kot-Wasik
    • Ulrik Kræmer Sundekilde
    2020 Full text Nutrients

    Commercial formula milk (FM) constitutes the best alternative to fulfill the nutritional requirements of infants when breastfeeding is precluded. Here, we present the comparative study of polar metabolite composition of human breast milk (HBM) and seven different brands of FM by nuclear magnetic resonance spectroscopy. The results of the multivariate data analysis exposed qualitative and quantitative differences between HBM and FM composition as well as within FM of various brands and in HBM itself (between individual mothers and lactation period). Several metabolites were found exclusively in HBM and FM. Statistically significant higher levels of isoleucine and methionine in their free form were detected in FM samples based on caprine milk, while FM samples based on bovine milk showed a higher level of glucose and galactose in comparison to HBM. The results suggest that the amelioration of FM formulation is imperative to better mimic the composition of minor nutrients in HBM.

  • Numerical analyses of novel prefabricated structural wall panels in residential buildings based on laboratory tests in scale 1:1
    • Łukasz Skarżyński
    • Ireneusz Marzec
    • Krzysztof Drąg
    • Andrzej Tejchman-Konarzewski
    2020 Full text European Journal of Environmental and Civil Engineering

    The paper presents experimental and numerical investigations on novel prefabricated composite building wall panels for residential building constructions. The wall panels were composed of reinforced concrete ribbed elements with the core from the EPS foam as the thermal insulation. The wall panels in the full-scale 1:1 were subjected to vertical loads. In the first step, the experiments were analysed with simple usual static methods. Next they were analysed numerically using the finite element method based on two different constitutive continuum models for concrete. First, an elasto-plastic model with the Drucker-Prager criterion defined in compression and with the Rankine criterion defined in tension was used. Second, a coupled elasto-plastic damage formulation based on the strain equivalence hypothesis was used. In order to properly describe strain localization in concrete, both models were enhanced in a softening regime by a characteristic length of micro-structure by means of a non-local theory. A satisfactory agreement between the experiments and FE analyses was achieved. In addition, the FE results with the non-local approach were compared with the crack band model.

  • Numerical analysis of high temperature minichannels heat exchanger performance
    • Jan Wajs
    • Tomasz Kura
    • Dariusz Mikielewicz
    • Elżbieta Fornalik-Wajs
    • Jarosław Mikielewicz
    2020

    Nowadays, the most difficult technological challenge in energy sector is connected with the gas micro-CHP units, dedicated to the distributed power generation. They are expected to be of high efficiency and at the same time of compact in size. Regarding the first reason, significant increase in microturbine efficiency can only be achieved by increase in the engine operating temperature. Therefore, one of the critical elements in such installation is the recuperator, which contributes to the overall microturbine efficiency in considerable part. Taking into account the system size and its efficiency, only the compact heat exchangers with passive techniques of the heat transfer intensification can fulfil strict requirements. Very promising are the cylindrical/plate heat exchangers with minichannels or heat exchangers with jets/microjets technology. In the paper an own construction of plate heat exchanger with minichannels, proposed for high-efficiency gas microturbine engines with external combustion chamber is considered. It consists of a set of steel plates with the channels of rectangular crossection, with 3 mm width and 1.5 mm depth. This unit can be supplied with air at temperature about 1000 C and transfer the thermal energy to air at temperature close to the ambient level. A numerical model was developed for the entire unit and validated with the experimental results, coming from the analysis conducted on the prototype in the “cold” conditions (at 18 C) and normal operating conditions (at 957 C). The experimental and numerical results, referring to the pressure drop, agreed within 2%-14% range, while referring to the heat rate – within 1%-7% range. Analysis of local thermal and hydraulic results was a source of few ideas, concerning an optimization of the heat exchanger construction, oriented at the improvement of its performance.

  • Numerical investigation on behaviour of cylindrical steel tanks during mining tremors and moderate earthquakes
    • Daniel Burkacki
    • Michał Wójcik
    • Robert Jankowski
    2020 Earthquakes and Structures

    Cylindrical steel tanks are important components of industrial facilities. Their safety becomes a crucial issue since any failure may cause catastrophic consequences. The aim of the paper is to show the results of comprehensive FEM numerical investigation focused on the response of cylindrical steel tanks under mining tremors and moderate earthquakes. The effects of different levels of liquid filling, the influence of non-uniform seismic excitation as well as the aspects of diagnosis of structural damage have been investigated. The results of the modal analysis indicate that the level of liquid filling is really essential in the structural analysis leading to considerable changes in the shapes of vibration modes with a substantial reduction in the natural frequencies when the level of liquid increases. The results of seismic and paraseismic analysis indicate that the filling the tank with liquid leads to the substantial increase in the structural response under ground motions. It has also been observed that the peak structural response values under mining tremors and moderate earthquakes can be comparable to each other. Moreover, the consideration of spatial effects related to seismic wave propagation leads to a considerable decrease in the structural response under non-uniform seismic excitation. Finally, the analysis of damage diagnosis in steel tanks shows that different types of damage may induce changes in the free vibration modes and values of natural frequencies.

  • Numerical Solution of the Two-Dimensional Richards Equation Using Alternate Splitting Methods for Dimensional Decomposition
    • Dariusz Gąsiorowski
    • Tomasz Kolerski
    2020 Full text Water

    Research on seepage flow in the vadose zone has largely been driven by engineering and environmental problems affecting many fields of geotechnics, hydrology, and agricultural science. Mathematical modeling of the subsurface flow under unsaturated conditions is an essential part of water resource management and planning. In order to determine such subsurface flow, the two-dimensional (2D) Richards equation can be used. However, the computation process is often hampered by a high spatial resolution and long simulation period as well as the non-linearity of the equation. A new highly efficient and accurate method for solving the 2D Richards equation has been proposed in the paper. The developed algorithm is based on dimensional splitting, the result of which means that 1D equations can be solved more efficiently than as is the case with unsplit 2D algorithms. Moreover, such a splitting approach allows any algorithm to be used for space as well as time approximation, which in turn increses the accuracy of the numerical solution. The robustness and advantages of the proposed algorithms have been proven by two numerical tests representing typical engineering problems and performed for typical properties of soil.

  • Numerical solutions for blood flow in elastic vessels
    • Henryk Leszczyński
    • Artur Poliński
    • Monika Wrzosek
    2020 MATHEMATICAL METHODS IN THE APPLIED SCIENCES

    We consider the differential–algebraic system for the blood flow and pressure in the systemic arteries. By the operator splitting method, we transform the system into the hyperbolic one, introduce the bicharacteristics, and perform the time–space nonuniform discretization, obtaining the innovative difference scheme. Our results are illustrated with numerical experiments.

  • Numerical Study of Concrete Mesostructure Effect on Lamb Wave Propagation
    • Beata Zima
    • Rafał Kędra
    2020 Full text Materials

    The article presents the results of the numerical investigation of Lamb wave propagation in concrete plates while taking into account the complex concrete mesostructure. Several concrete models with randomly distributed aggregates were generated with the use of the Monte Carlo method. The influence of aggregate ratio and particle size on dispersion curves representing Lamb wave modes was analyzed. The results obtained for heterogeneous concrete models were compared with theoretical results for homogeneous concrete characterized by the averaged macroscopic material parameters. The analysis indicated that not only do the averaged material parameters influence the dispersion solution, but also the amount and size of aggregate particles. The study shows that Lamb waves propagate with different velocities in homogeneous and heterogeneous models and the difference increases with aggregate ratio and particle size, which is a particularly important observation for wave-based diagnostic methods devoted to concrete structures.