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Gdańsk University of Technology

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  • Determination of long-chain aldehydes using a novel quartz crystal microbalance sensor based on a biomimetic peptide
    • Tomasz Wasilewski
    • Bartosz Szulczyński
    • Marek Wojciechowski
    • Wojciech Kamysz
    • Jacek Gębicki
    2020 MICROCHEMICAL JOURNAL

    There is an increasingly popular trend aimed at improvement of fundamental metrological parameters of sensors via implementation of materials mimicking biological olfactory systems. This study presents investigation on usefulness of the peptide mimicking HarmOBP7 region as a receptor element of the piezoelectric sensor for selective analysis of long-chain aldehydes. Identification of odorant binding proteins creates new possibilities for design of peptides mimicking binding properties of their volatile compounds. Exploration of OBPs and new peptide sequences capable to effectively bind volatile compounds is necessary to enhance artificial olfaction. For the development of biosensors where simple detection is crucial rather than identification of subsequent metabolic activity, the use of sub-protein components (e.g. ligand-binding regions or synthetic peptides) is still escalating. Bearing all this in mind, a segment of a peptide sequence associated with a specific function of HarmOBP7 (involved in binding the long-chain aldehydes) has been designed, synthesised and immobilised on a piezoelectric transducer. The results of in silico investigations were correlated with the experimental measurements of gas substances. The correlated results confirm a high selectivity of the KLLFDSLTDLKKKMSEC-based sensor with respect to long-chain aliphatic aldehydes including octanal, decanal, undecanal, nonanal and helional. Odorant molecules interact with recognition peptide with specific affinities. The lowest limit of detection, 14 ppm was calculated for nonanal. The results can throw a new light on the possibility of synthetic peptide application as a receptor layer in biosensors in odorants analysis.

  • Determination of phenol biodegradation pathways in three psychrotolerant yeasts, Candida subhashii A011, Candida oregonensis B021 and Schizoblastosporion starkeyi-henricii L012, isolated from Rucianka peatland
    • Natalia Filipowicz
    • Malwina Momotko
    • Grzegorz Boczkaj
    • Hubert Cieśliński
    2020 Full text ENZYME AND MICROBIAL TECHNOLOGY

    In this study, three psychrotolerant phenol-degrading yeast strains Candida subhashii (strain A011), Candida oregonenis (strain B021) and Schizoblastosporion starkeyi-henricii (strain L012) isolated from Rucianka peatland were examined to determine which alternative metabolic pathway for phenol biodegradation is used by these microorganisms. All yeast strains were cultivated in minimal salt medium supplemented with phenol at 500, 750 and 1000 mg l−1 concentration with two ways of conducting phenol biodegradation experiments: with and without the starving step of yeast cells. For studied yeast strains, no catechol 2,3-dioxygenase activities were detected by enzymatic assay and no products of catechol meta-cleavage in yeast cultures supernatants (GC–MS analysis), were detected. The detection of catechol 1,2-dioxygenase activity and the presence of cis,cis-muconic acid in the analyzed samples revealed that all studied psychrotolerant yeast strains were able to metabolize phenol via the ortho-cleavage pathway. Therefore, they may be tested in terms of their use to develop biotechnology for the production of cis,cis-muconic acid, a substrate used in the production of plastics (PET) and other valuable goods.

  • DETERMINATION OF SEAKEEPING PERFORMANCE FOR A CASE STUDY VESSEL BY THE STRIP THEORY METHOD
    • Karol Niklas
    • Artur Karczewski
    2020 Full text Polish Maritime Research

    The increase of seakeeping performance is of particular importance for car and passenger ferries, service ships in the gas and oil extraction industry and offshore wind power farm industry, as well as for special purpose ships (including military applications). In the water areas of the Baltic Sea, North Sea, and Mediterranean Sea, which are characterised by a short and steep wave, the hull shape has a substantial impact on the operational capacity and propulsion efficiency of the ship, as well as on comfort and safety of navigation. The article analyses selected aspects of seakeeping for four variants of a selected case study vessel, indicating practical limitations of the strip method. The analysed aspects included hull heaving and pitching, added resistance, Motion Thickness Indicator (MSI), and Subjective Magnitude (SM). Experimental tests were also performed in the towing tank. Their comparison with the numerical results has indicated high inaccuracy of the strip method. What is more, the simplified representation of hull shape used in the strip method makes it impossible to analyse the effect of hull shape changes on the predicted seakeeping characteristics. Especially for the case of head wave, neglecting highly non-linear phenomena, such as slamming or head wave breaking, in strip method-based computer simulations will significantly decrease the reliability of the obtained results. When using the strip method, the seakeeping analysis should be complemented with model tests in a towing tank, or by another more complex numerical analysis, such as CFD for instance.

  • Determination of the Bending Properties of Wire Rope Used in Cable Barrier Systems
    • Dawid Bruski
    2020 Full text Materials

    This paper presents research on the bending properties of 3 × 7 19-mm wire rope commonly used in road cable barriers. A total of 19 experimental tests were conducted. In addition, two nonlinear 3D numerical models of the wire rope using beam and solid finite elements were developed. Based on these models, four numerical simulations were carried out. The numerical results were validated against the experimental ones and a very good agreement was obtained. The main result of the research is the determination of the moment–curvature relationship for the wire rope considered. The effect of prestretching on the rope performance is discussed. The numerical results are analyzed in this paper in detail, including the behavior of the wire rope under bending and analyses of the cross-sectional and contact stresses. Suggestions concerning the type of finite element for wire rope modeling are also given. The results can be used, for example, in numerical simulations of crash tests of cable barriers.

  • Determination of the dynamic critical maneuvering area in an encounter between two vessels: Operation with negligible environmental disruption
    • Mateusz Gil
    • Jakub Montewka
    • Przemysław Krata
    • Tomasz Hinz
    • Spyros Hirdaris
    2020 Full text OCEAN ENGINEERING

    This paper introduces the concept of Collision Avoidance Dynamic Critical Area (CADCA) for onboard Decision Support Systems (DSS). The indicator proposed is derived via identification of a minimum required maneuvering zone in an encounter between two vessels. The CADCA model accounts for ship maneuvering dynamics and associated hydrodynamic actions emerging from different rudder angles and forward speed effects. The method presented is novel as it considers the variability of a critical area due to dynamic changes in operational parameters for both vessels. Results of the simulations carried out in negligible weather conditions confirm that computed zones may differ significantly in terms of shapes and limits. It is demonstrated that the size of the CADCA depends on the rudder angle, forward speed, as well as the dimensions of the vessels.

  • DETERMINATION OF THE EFFECT OF ENVIRONMENTAL FACTORS ON THE CORROSION OF WATER DISTRIBUTION SYSTEM BASED ON ANALYSIS OF ON-LINE CORROSION MONITORING RESULTS
    • Agata Jażdżewska
    • Maciej Gruszka
    • Robert Mazur
    • Juliusz Orlikowski
    • Jacek Banaś
    2020 Full text ARCHIVES OF METALLURGY AND MATERIALS

    Corrosion of water distribution system is a significant issue causing problems with quality, safety and continuity of distribution. The changes of corrosion rates of the water distribution systems in Cracow made of carbon steel were investigated by analysis of online corrosion monitoring system results. Corrosion rates were determined using the linear polarization method. The impact of rain, temperatures, conductivity, dissolved oxygen content on corrosion rate were characterized. The corrosivity of different water sources like mountain water, underground water or river water were indicated. The possible actions for reducing corrosion losses were characterized. Results show that pollution of the environment in the form of acid rain and runoff from agriculture as well as the type of the source water has significant influence on corrosion of water distribution system. Corrosion monitoring system gives possibility of controlling corrosion rate by mixing waters from different sources in the way to obtain less corrosive mixture

  • DETERMINATION OF THE HYDROXYL NUMBER OF GROUND TIRE RUBBER PARTICLES VIA MODIFIED TEST METHOD FOR ISOCYANATE GROUPS
    • Aleksander Hejna
    • Paulina Kosmela
    • Adam Olszewski
    • Łukasz Zedler
    • Krzysztof Formela
    2020 Full text

    Nowadays, considering the environmental trends and law regulations associated with the circular economy, it is very important to seek for the methods of by-products and waste utilization. The example of such material, which requires the attention and recycling method is ground tire rubber generated during recycling of post-consumer car tires. It can be introduced into various polymer matrices as a filler, but to enhance its effectivity it is essential to guarantee the interfacial compatibility. Therefore, the fast and simple methods for determination of the waste rubber chemical structure are needed. In the presented paper, we are presenting the method for the determination of hydroxyl number of ground tire rubber, based on the modified standard test method for isocyanate groups. Hydroxyl number is used as a quantitative measure of the hydroxyl groups content, which is essential during manufacturing of multiple polymeric materials, such as polyurethanes, epoxy resins, polyesters or polyamides. Moreover, the presence of hydroxyls on the rubber surface may be exploited during compatibilization of composites.

  • Determination of the theoretical and actual working volume of a hydraulic motor
    • Paweł Śliwiński
    2020 Full text ENERGIES

    A new methodology of determination of the theoretical and actual working volume of a hydraulic motor based on the characteristics of the delivered flow rate into hydraulic motor vs. the rotational speed at a constant pressure drop in the working chambers is described in this paper. A new method of describing the delivered flow rate into a motor per one shaft revolution as a nonlinear function of the pressure drop in the motor working chamber is proposed. The influence of the flowmeter location in the measurement system on the result of the theoretical and actual working volume calculation is described. It is shown that, in order to assess the energy losses (volumetric and mechanical) in the motor, the actual working volume must be a polynomial function (third degree) of its pressure drop in the working chambers. The result of the experimental tests of the satellite hydraulic motor confirmed the validity of the proposed method. The result of the calculation of the theoretical working volume of the motor according to the proposed method was compared with the results of calculations according to known methods.

  • Determination of the tram track axis using a multi receiver GNSS measurement system
    • Andrzej Wilk
    • Cezary Specht
    • Władysław Koc
    • Krzysztof Karwowski
    • Jacek Skibicki
    • Jacek Szmagliński
    • Paweł Dąbrowski
    • Mariusz Specht
    • Marek Zienkiewicz
    • Sławomir Judek
    • Piotr Chrostowski
    • Marcin Skóra
    • Sławomir Grulkowski
    2020 Full text Przegląd Komunikacyjny

    This article refers to research, that has been conducted by an interdisciplinary research team from the Gdańsk University of Technology and the Maritime University in Gdynia since 2009. These investigation concerns the determination of a railway track axis using the mobile satellite measurement technique. Following the dynamic development of GNSS techniques, that could be seen in the last decade, the team carried out further experiments aimed at developing an effective measurement method. Using the acquired experience in this period, another measurement campaign was carried out on the tram tracks in Gdansk. The main goal of these measurements was to check how the new assumptions regarding the method of mounting the antennas as well as their placement on the measuring platform will work in various field conditions. For this purpose, ten sets of GNSS receivers offered by two independent manufacturers – currently market leaders – were used. The choice of testing track section made it possible to analyze the repeatability of results obtained from multiple measurements in conditions of varying GNSS signal availability. The article presents in a synthetic way the course of this research and the obtained results.

  • DETERMINATION OF VERTICAL DISPLACEMENTS IN RELATIVE MONITORING NETWORKS
    • Daria Filipiak-Kowszyk
    • Waldemar Kamiński
    2020 Full text Archives of Civil Engineering

    The problem of determining displacements of objects is an important and current issue, in particular in terms of operational safety. This is a requirement that covers geodetic, periodic control measurements in order to determine horizontal and vertical displacements. The paper is focused on the analysis of vertical displacements. Geodetic measurements and their interpretation allow to reduce the risk of possible structural catastrophes. The major research topic of the majority of available papers is displacement determination of individual controlled points, in a situation where there are identified as fixed reference points. There are cases making identification of such points difficult or impossible to use in displacement analysis. This paper addresses a rare case of determining vertical displacements in unstable reference systems. Due to the fact that most of the existing and known literature methods do not always bring satisfactory results, the paper propose a new method of vertical displacement determination in the absence of reference points in the local coordinate system. Practical considerations on simulated data show that the presented method performs the task correctly.

  • Developing students' spatial skills and teaching the history of architecture through structural drawing
    • Maria Sołtysik
    2020 Full text World Transactions on Engineering and Technology Education

    The method of “structural drawing" is used in teaching history of architecture in the Architectural Faculty of Gdańsk University of Technology. It is addressed to students of the first semester of study – so to the architectural beginners. There are three main goals of the structural drawing method used in that educational course: (1) developing the students’ spatial skills; (2) training architectural drawing ability; (3) teaching the history of architecture. The method of structural drawing is based on creating the axonometric and the orthogonal views of the historic architectural objects, important to the outline of architecture. Every exercise lasts 1,5 hour, during which every student is creating a hand-drawing spatial study of one given object. The process of drawing is performed in a “structural” way, which means that all phases of its construction are visible and the very object is presented spatially as if it was transparent. Those are the main rules of “structural drawing”. The first part of the exercise – mostly the axonometric projection - is commented and guided by the teacher. During it the students are doing the drawings simultaneously to the drawing performed by the teacher on the table. The second part of the exercise is done by every student on his own, without the teacher’s guidance. It concerns the structural drawing of a chosen orthogonal view of the object or a chosen architectural detail.

  • Development and validation of a GC–MS/MS method for the determination of 11 amphetamines and 34 synthetic cathinones in whole blood
    • Mateusz Woźniak
    • Laura Banaszkiewicz
    • Marek Wiergowski
    • Ewa Tomczak
    • Marzena Kata
    • Beata Szpiech
    • Jacek Namieśnik
    • Marek Biziuk
    2020 Full text Forensic Toxicology

    Purpose Psychoactive compounds that contain a phenylethylamine structure (such as amphetamine-type stimulants and synthetic cathinones) are one of the major classes of stimulants on the recreational drug market. Approximately 670 new psychoactive substances (NPS) are monitored only in Europe; however, new psychoactive compounds are being developed for illicit trade each year. In this context, the development of new analytical procedures for the determination of such compounds in biological specimens for forensic toxicology is of great importance. Methods Gas chromatography–tandem mass spectrometry (GC–MS/MS) technique was applied for analysis of amphetamines and synthetic cathinones. The volumes of 200 µL of each whole blood sample and 1 mL of liquid-liquid extraction solvent were used for extraction, followed by pentafuoropropionyl derivatization. Results A high-throughput, robust, rapid, and sensitive procedure involving a simple liquid-liquid extraction for the simultaneous determination of 45 amphetamine-type stimulants and synthetic cathinones in whole blood was developed. The assay was validated based on its recovery (83.2–106%), interday accuracy (89.0–108%), and interday precision (≤8.1%). In view of the low limits of detection (ranged between 0.02 and 0.72 ng/mL) and limits of quantifcation (1 and 2.5 ng/mL), the developed method can serve as a less expensive and more ecologically friendly alternative to the liquid chromatography–tandem mass spectrometric methods. Conclusions To the best of our knowledge, this is the frst work presenting a GC–MS/MS method for the determination of NPS in blood samples. The presented procedure was applied to authentic samples from forensic cases, demonstrating its utility in the quantifcation of a wide number of psychoactive substances in routine toxicological analyses. The developed procedure can also be easily expanded to additional compounds.

  • Development of a Peptide Derived from Platelet-Derived Growth Factor (PDGF-BB) into a Potential Drug Candidate for the Treatment of Wounds
    • Milena Deptuła
    • Przemysław Karpowicz
    • Anna Wardowska
    • Piotr Sass
    • Paweł Sosnowski
    • Alina Mieczkowska
    • Natalia Filipowicz
    • Maria Dzierżyńska
    • Justyna Sawicka
    • Ewa Nowicka
    • Paulina Langa
    • Adriana Schumacher
    • Mirosława Cichorek
    • Jacek Zieliński
    • Karolina Kondej
    • Franciszek Kasprzykowski
    • Artur Czupryn
    • Łukasz Janus
    • Piotr Mucha
    • Piotr Skowron
    • Arkadiusz Piotrowski
    • Paweł Sachadyn
    • Sylwia Rodziewicz-Motowidło
    • Michał Pikuła
    2020 Advances in Wound Care

    Objective: This study evaluated the use of novel peptides derived from platelet-derived growth factor (PDGF-BB) as potential wound healing stimulants. One of the compounds (named PDGF2) was subjected for further research after cytotoxicity and proliferation assays on human skin cells. Further investigation included evaluation of: migration and chemotaxis of skin cells, immunological and allergic safety, the transcriptional analyses of adipose-derived stem cells (ASCs) and dermal fibroblasts stimulated with PDGF2, and the use of dorsal skin wound injury model to evaluate the effect of wound healing in mice. Approach: Colorimetric lactate dehydrogenase and tetrazolium assays were used to evaluate the cytotoxicity and the effect on proliferation. PDGF2 effect on migration and chemotaxis was also checked. Immunological safety and allergic potential were evaluated with a lymphocyte activation and basophil activation test. Transcriptional profiles of ASCs and primary fibroblasts were assessed after stimulation with PDGF2. Eight-week-old BALB/c female mice were used for dorsal skin wound injury model. Results: PDGF2 showed low cytotoxicity, pro-proliferative effects on human skin cells, high immunological safety, and accelerated wound healing in mouse model. Furthermore, transcriptomic analysis of ASCs and fibroblasts revealed the activation of processes involved in wound healing and indicated its safety. Innovation: A novel peptide derived from PDGF-BB was proved to be safe drug candidate in wound healing. We also present a multifaceted in vitro model for the initial screening of new compounds that may be potentially useful in wound healing stimulation. Conclusion: The results show that peptide derived from PDGF-BB is a promising drug candidate for wound treatment.

  • Development of cooperation in localized cooperation networks: A comparative study of cluster organizations and technology parks
    • Anna Lis
    2020 Full text

    The main aim of the paper is to analyze the level of development of cooperative relationships in localized cooperation networks – among enterprises associated in cluster organizations and park tenants. The author reports the findings from the quantitative study carried out in the selected cluster organizations and technology parks functioning in Poland. The basic method of data collection was a survey questionnaire. The research sample included 132 respondents from cluster enterprises and 137 from park tenants. In addition, a comparative analysis was conducted. The research is based on the original concept of the trajectory of development of cooperative relationships in cluster organizations. The current study focused on three main areas of inter-organizational cooperation: motivation, effectiveness, and commitment. The effectiveness of the surveyed enterprises in both groups should be assessed as quite low, while their attitude as passive. The study shows that the most common forms of cooperation are those assigned to the lowest level of cooperation – the surveyed enterprises achieved level I, regardless of their initial motivation. At this level, the surveyed enterprises also showed the greatest commitment. In contrast, it was the most difficult for them to achieve the highest level IV, which requires the highest level of commitment. The knowledge of the identified relationships among motivation, effectiveness, and commitment in cluster and park structures can help these organizations to take conscious actions aimed at developing cooperation among their members/tenants. The findings add to the state-of-the-art knowledge in the concept of industrial clusters, as they shed new light on cooperation developed within formally established organizations, based on geographical proximity, focused on the networking of their constituent companies.

  • Development of proximity in cluster organizations
    • Anna Lis
    2020 Full text Entrepreneurship and Sustainability Issues

    Sustainable development in cluster organizations (COs) is most fully manifested in the synergy effect. In turn, the synergy effect is achieved thanks to the development of proximity among cluster entities. The purpose of the paper is to test two conceptual models reflecting relations between selected dimensions of proximity in cluster organizations. The author reports the findings of a quantitative study conducted in four COs. The basic technique for collecting data was an online questionnaire. Both theoretical models were tested using Structural Equation Modelling.The research goes beyond the state-of-the-art knowledge in the concept of industrial cluster by exposing a broader view on cluster cooperation, which is developed on the basis of geographical proximity, and simultaneously contributes to the development of proximity in other dimensions: social, competence and organizational.

  • Development of the New Polish Method for Capacity Analysis of Motorways and Expressways
    • Piotr Olszewski
    • Tomasz Dybicz
    • Wojciech Kustra
    • Aleksandra Romanowska
    • Kazimierz Jamroz
    • Ostrowski Krzysztof
    2020 Full text Archives of Civil Engineering

    The paper presents development of the new Polish method for performing capacity analysis of basic segments of dual carriageway roads (motorways and expressways). The method is based on field traffic surveys conducted at 30 motorway and expressway sites (class A and S roads) in Poland. Traffic flows, composition and travel times were observed in 15-min intervals at each site using ANPR filming method. These data were used to calibrate a family of traffic speed-flow relationships for different roads, based on Van Aerde model. Free flow speed of traffic and road class are the basic parameters defining the speed-flow relationship and the value of capacity per lane in pcu/h. Traffic density was adopted as the measure of effectiveness for defining the level of service. The paper describes derivation of formulae for estimation of free flow speed for different types of roads as well as determination of equivalent factors for converting vehicles to passenger car units. The method allows us to determine capacity and the level of service based on existing or forecasted traffic flow.

  • Dia- and paramagnetic contributions to magnetizabilities of relativistic hydrogenlike atoms in some low-lying discrete energy eigenstates
    • Patrycja Stefańska
    2020 Full text ATOMIC DATA AND NUCLEAR DATA TABLES

    In this paper we present tabulated data for relative diamagnetic and paramagentic contributions to the magnetizability ($\chi$) of the relativistic hydrogenlike atoms with a pointlike, motionless and spinless nucleus of charge $Ze$. Utilizing general analytical formulas for the diamagnetic ($\chi_{d}$) and paramagnetic ($\chi_{p}$) components of $\chi$, recently derived by us [P. Stefa{\'n}ska, 2020] with the aid of the Gordon decomposition technique, valid for an arbitrary discrete energy state, we have computed the numerical values of $\chi_{d}/\chi$ and $\chi_{p}/\chi$ for the ground state and for the first and second set of excited states (i.e.: $2s_{1/2}$, $2p_{1/2}$, $2p_{3/2}$, $3s_{1/2}$, $3p_{1/2}$, $3p_{3/2}$, $3d_{3/2}$, and $3d_{5/2}$) of the hydrogen atom ($Z=1$) and for hydrogenic ions with $2 \leqslant Z \leqslant 137$. We compare also the numerical values of the total magnetizabilities for the ground state $1s_{1/2}$ and for each state belonging to the first set of excited states of selected hydrogenlike atoms, obtained with the use of two different values of the fine-structure constant, i.e.: $\alpha^{-1}=137.035 \: 999 \: 139$ (from CODATA 2014) and $\alpha^{-1}=137.035 \: 999 \: 084$ (from CODATA 2018).

  • Diagnostic Models and Estimators for LDI in Transmission Pipelines
    • Zdzisław Kowalczuk
    • Marek Tatara
    2020 Full text

    This article considers and compares four analytical models of the pipeline flow process for leak detection and location tasks. The synthesis of these models is briefly outlined. Next, the methodology for generating data and diagnosing pipes is described, as well as experimental settings, assumptions and implemented scenarios. Finally, the quality of model-based diagnostic estimators has been evaluated for their bias, standard deviations and computational complexity. The global level of optimality served as a general indicator of the quality and performance of multidimensional estimators.

  • Diamine derivatives of dimerized fatty acids and bio-based polyether polyol as sustainable platforms for the synthesis of non-isocyanate polyurethanes
    • Kamila Błażek
    • Paulina Kasprzyk
    • Janusz Datta
    2020 Full text POLYMER

    A series of environmentally friendly non-isocyanate polyurethanes (NIPUs) were successfully prepared via the polyaddition reaction of bio-based polyether polyol-based cyclic carbonate with diamine derivative of dimerized fatty acids. The syntheses of NIPUs were realized by the three-step method in the absence of toxic solvents and, importantly, the process of carbonation did not require the use of elevated pressure. The effect of using various types of bio-based amines, [amine]/[cyclic carbonate] molar ratio as well as different reaction temperatures on the chemical structure and thermal properties were widely investigated by Fourier transform infrared spec-troscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA), respectively. The Gaussian deconvolution technique was used to decompose the carbonyl region (-C––O) of three peaks in various samples. It was found that the molar ratio of substrates and curing temperature have an effect on the distribution of free and H-bonded carbonyl groups as well as carbonyl groups from cyclic carbonates in the chemical structure of the prepared compounds. On this basis, the role of hydrogen bonds in the chemical structure of NIPU on selected sample properties was determined. Moreover, the impact of water during 6 months of immersion on the polymer networks was examined.

  • Diastereoselective Synthesis of Z‐Alkenyl Disulfides from α‐Thiophosphorylated Ketones and Thiosulfonates
    • Mateusz Musiejuk
    • Justyna Doroszuk
    • Bartosz Jędrzejewski
    • Gregory Ortiz Nieto
    • Marisol Marin Navarro
    • Dariusz Witt
    2020 ADVANCED SYNTHESIS & CATALYSIS

    We developed a simple and efficient method for the synthesis of functionalized unsymmetrical Z‐alkenyl disulfides under mild conditions in moderate to good yields. The designed method is based on the reaction of α‐thiophosphorylated carbonyl compounds with thiotosylates in the presence of a base. The developed method allows the preparation of unsymmetrical Z‐alkenyl disulfides bearing additional hydroxy, carboxy, or ester functionalities

  • Diatoms Biomass as a Joint Source of Biosilica and Carbon for Lithium-Ion Battery Anodes
    • Andrzej Nowak
    • Myroslav Sprynskyy
    • Izabela Wojtczak
    • Konrad Trzciński
    • Joanna Wysocka
    • Mariusz Szkoda
    • Bogusław Buszewski
    • Anna Lisowska-Oleksiak
    2020 Full text Materials

    The biomass of one type cultivated diatoms (Pseudostaurosira trainorii), being a source of 3D-stuctured biosilica and organic matter—the source of carbon, was thermally processed to become an electroactive material in a potential range adequate to become an anode in lithium ion batteries. Carbonized material was characterized by means of selected solid-state physics techniques (XRD, Raman, TGA). It was shown that the pyrolysis temperature (600 °C, 800 °C, 1000 °C) affected structural and electrochemical properties of the electrode material. Biomass carbonized at 600 °C exhibited the best electrochemical properties reaching a specific discharge capacity of 460 mAh g−1 for the 70th cycle. Such a value indicates the possibility of usage of biosilica as an electrode material in energy storage applications

  • Dielectric Barrier Discharge Systems with HV Generators and Discharge Chambers for Surface Treatment and Decontamination of Organic Products
    • Jan Mucko
    • Robert Dobosz
    • Ryszard Strzelecki
    2020 Full text ENERGIES

    The article presents applications of systems with power electronic converters, high voltage transformers, and discharge chambers used for nonthermal, dielectric barrier discharge plasma treatment of a plastic surface and decontamination of organic loose products. In these installations, the inductance of the high voltage transformers and the capacitances of the electrode sets form resonant circuits that are excited by inverters. The article presents characteristic features of the installations and basic mathematical relationships as well as the impact of individual parameters of system components. These converters with their output installations were designed, built, and tested by the authors. Some of the converters developed by the authors are manufactured and used in the industry.

  • Differential analysis of dynamic immittance spectra
    • Kazimierz Darowicki
    • Artur Zieliński
    2020 Full text ELECTROCHEMISTRY COMMUNICATIONS

    This work presents a new approach to the analysis of immittance spectrograms of systems characterised by non-stationarity. The possibility of linking the evolution of the immittance response with changes in the parameters describing the system is achieved by introducing a spectrum in differential form. By using the above procedure, it becomes possible to separate elements with a dependence (or lack thereof) from an independent variable appearing in the dynamic electrochemical impedance method. The work illustrates the usefulness of this approach for the elementary components used to model the behaviour of electrochemical systems.

  • Digital Filtering of Railway Track Coordinates in Mobile Multi–Receiver GNSS Measurements
    • Andrzej Wilk
    • Władysław Koc
    • Cezary Specht
    • Sławomir Judek
    • Krzysztof Karwowski
    • Piotr Chrostowski
    • Krzysztof Czaplewski
    • Paweł Dąbrowski
    • Sławomir Grulkowski
    • Roksana Licow
    • Jacek Skibicki
    • Mariusz Specht
    • Jacek Szmagliński
    2020 Full text SENSORS

    The article discusses an important issue in connection with the technique of mobile Global Navigation Satellite System (GNSS) measurements of railway track coordinates, which is digital filtering performed to precisely determine railway track axes. For this purpose, a measuring technique is proposed which bases on the use of a measuring platform with a number of appropriately distributed GNSS receivers, where two of them determine the directional base vector of the platform. The receivers used in the research had high measuring frequency in the Real Time Kinematic (RTK) operating mode and enabled correction of the obtained results in post–processing. A key problem discussed in the article is the method for assessing the quality of the measurement results obtained from GNSS receivers, and their preparation for further processing making use of geometrically constrained parameters of the base vector and specialized digital filtering, among other elements, to precisely determining the track axis. The obtained results confirm the applicability of the used method of GNSS signal processing.

  • Direct modulation for conventional matrix converters using analytical signals and barycentric coordinates
    • Paweł Szczepankowski
    • Tomasz Bajdecki
    • Ryszard Strzelecki
    2020 Full text IEEE Access

    This paper proposes the generalized direct modulation for Conventional Matrix Converters (CMC) using the concept of analytical signals and barycentric coordinates. The paper proposes a novel approach to the Pulse Width Modulation (PWM) duty cycle computing, which allows faster prototyping of direct control algorithms. The explanation of the new idea using analytical considerations demonstrating the principles of direct voltage synthesis has been presented in the article. The study concerns mainly the CMC3x3 but solutions for 3xn, 5x5, and 5x3 topologies have also been discussed. The transformation of instantaneous input voltages to analytic signals great permits for simple presenting of real input voltage conditions such as waveform type, asymmetry or other deformation like higher-order harmonics. The proposed interpolation methods allow for determining the values of PWM duty cycles using simple formulas based on the determinants of the 2nd-degree matrices. Therefore, the proposed method, which based on the barycentric coordinates, frees an algorithm from trigonometry and angles.

  • Direction-of-Arrival Estimation Methods in Interferometric Echo Sounding
    • Piotr Grall
    • Iwona Kochańska
    • Jacek Marszal
    2020 Full text SENSORS

    Nowadays, there are two leading sea sounding technologies: the multibeam echo sounder and the multiphase echo sounder (also known as phase-dierence side scan sonar or bathymetric side scan sonar). Both solutions have their advantages and disadvantages, and they can be perceived as complementary to each other. The article reviews the development of interferometric echo sounding array configurations and the various methods applied to determine the direction-of-arrival. “Interferometric echo sounder” is a broad term, applied to various devices that primarily utilize phase dierence measurements to estimate the direction-of-arrival. The article focuses on modifications to the interferometric sonar array that have led to the state-of-the-art multiphase echo sounder. The main algorithms for classical and modern interferometric echo sounder direction-of-arrival estimation are also outlined. The accuracy of direction-of-arrival estimation methods is dependent on the configuration of the array and external and internal noise sources. The main sources of errors, which influence the accuracy of the phase dierence measurements, are also briefly characterized. The article ends with a review of the current research into improvements in the accuracy of interferometric echo sounding and the application of the principle of interferometric in other devices.

  • Disaster-Resilient Routing Schemes for Regional Failures
    • Teresa Gomes
    • Dorabella Santos
    • Rita Girão-Silva
    • Lúcia Martins
    • Boro Nedic
    • Matthias Gunkel
    • Balázs Vass
    • János Tapolcai
    • Jacek Rak
    2020

    Large-scale natural disasters can have a profound effect on the telecommunication services in the affected geographical area. Hence, it is important to develop routing approaches that may help in circumventing damaged regional areas of a network. This prompted the development of geographically diverse routing schemes and also of disaster-risk aware routing schemes. A minimum-cost geodiverse routing, where a minimum geographical distance value D is imposed between any intermediate element of one path and any element of the other path, is presented. Next, the problem of the calculation of a D-geodiverse routing solution which ensures a certain level of availability is tackled. An algorithm is described that either obtains a solution to that problem or the most available path pair satisfying the desired geographical distance value D—this can be useful for the specification of availability levels in Service Level Agreements. Finally, a case study is presented, in an optical network, to determine the cost increase in terminal equipment (transponders) of approaches to ensure a much larger separation of the paths (of the selected path pair), with respect to minimal length link-disjoint routing.

  • Discrepancies in determination of biogenic amines in beer samples by reversed phase and hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry
    • Katarzyna Nalazek-Rudnicka
    • Paweł Kubica
    • Andrzej Wasik
    2020 Full text MICROCHEMICAL JOURNAL

    Biogenic amines (BAs) are nitrogenous organic bases occurring mainly in fermented food and beverages as a result of free amino acids bacterial decarboxylation. The reversed phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC) based methods were compared in terms of usefulness for determination of BAs in beer samples. Analysis of BAs with the use of RPLC method were carried out after their derivatization with p-toluenesulfonyl chloride (tosyl chloride), while for HILIC one sample preparation consisted of only dilution. For RPLC method the limits of detection (LODs) and quantitation (LOQs) were in the range 0.54-4.3 ng/mL and 1.6–13 ng/mL, respectively. The obtained recoveries were from 75 to 125% with coefficient of variation (CV) less than 8%. The developed HILIC based method turned out to be less sensitive and not specific sufficiently for the determination of most BAs in native state in beer samples. In this case, the LODs and LOQs values were in the range 12-94 ng/mL and 35–290 ng/mL, respectively.The observed matrix effects during analysis of beer samples were significant enough to distort the BAs content. The obtained recoveries were often below 75% with CVs less than 11%. Finally, both developed methods were applied for analysis of BAs in samples of lager beers. Due to the low recoveries and strong influence of matrix the HILIC method could be only applied to qualitative analysis of some BAs in beer samples. Regardless of the relatively lengthy sample preparation for RPLC method (time of derivatization – 2h), it was proven that a derivatization reaction is required for such matrix as beer.

  • Discussing daylight simulations in a proposal for online daylighting education.
    • Federica Giuliani
    • Mandana Khanie, Sarey
    • Natalia Sokół
    • Niko Gentile,
    2020

    There is increasing interest concerning daylighting in the building sector. However, such knowledge is difficult to penetrate the curricula of architects and designers as existing educational programmes often do not provide sufficient training on BPS. This also leads to superficial use of daylight simulations. This paper presents a proposal for a needs-based education package on daylighting design, that mixes modular eLearning and an intensive summer school, called NLITED. The NLITED model includes modules on daylight simulation whose implementation (in eLearning key) can trigger a constructive discussion and receive valuable feedback from the Nordic community of BPS specialists.

  • Discussion of “Axisymmetric Simulations of Cone Penetration in Saturated Clay” by Diane M. Moug, Ross W. Boulanger, Jason T. DeJong, and Robert A. Jaeger
    • Jakub Konkol
    • Lech Bałachowski
    2020 Full text JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING

    N/A

  • Discussion of “CPT Evaluation of Yield Stress Profiles in Soils” by Shehab S. Agaiby and Paul W. Mayne
    • Lech Bałachowski
    2020 Full text JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING

    Veryfication of the procedure to estimate overconsolidation ratio in sands using the results of mini-cone penetration tests in centrifuge.

  • Discussion:Horizontal stress increase induced by deep vibratory compaction
    • K. Rainer Massarsch
    • Carl Wersäll
    • Bengt H. Fellenius
    • Lech Bałachowski
    • Norbert Kurek
    • Jakub Konkol
    2020 Full text PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS-GEOTECHNICAL ENGINEERING

    Deep compaction control of granular material using the results of field tests. The analysis include the CPTU and DMT tests terformed before and after compaction works.

  • Displacement piles - classification and methods for the calculation of bearing capacity.
    • Paweł Więcławski
    • Kazimierz Gwizdała
    2020 Full text Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

    Displacement piles belong to a group of technologies whose main idea is to install or make a pile without extracting ground material. According to definition, contained in PN-EN:1997-1:2008, displacement piles should be considered as driven, pressed in using vibrators and made with the use of spread augers. The classification of piles used so far with regard to the technology of execution is modified. An additional element is the emergence of new materials and plastics used in the construction of piles. The paper presents technological changes concerning not only the method of construction, but also the materials used. Another aspect is the methods of calculating the load-bearing capacity and settlement of piles. With acceptance for use the PN-EN:1997-1:2008 standard in 2010, it was necessary to change the approaches applied that based on many years of experience and tradition. The treatment of old methods was undertaken by defining coefficients allowing extrapolation of the load capacity from the range of critical values to the limit values. To a large extent these are empirical procedures. The main determinant in the process of designing and then verifying the load-bearing capacity of piles has been the determination of the force that causes settlement equal to 10% of the pile diameter. The best method in this case is to forecast the full load-settlement characteristics. The paper presents methods based on a hyperbolic model of the settlement curve, adopted mainly in tranformational functions, and a complex linear- exponential model, which reflects with high accuracy the cooperation of the substrate with displacement piles with a Increased base. On the basis of the collected data, a comparative analysis of particular displacement piles technologies was made. The characteristic elements of cooperation between the subsoil and piles were defined depending on the method of their execution. The usefulness of individual methods of load-bearing capacity calculation depending on the pile technology was determined.

  • Dissimilar underwater wet welding of HSLA steels
    • Jacek Tomków
    • Dariusz Fydrych
    • Grzegorz Rogalski
    2020 Full text INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY

    The high-strength low-alloy S460ML and S460N steels were chosen for underwater wet welding of dissimilar T-joints using covered electrodes. For improving the quality of joints, the temper bead welding (TBW) method was used. The application of TBW in pad welding conditions has been investigated earlier but the possibility of usage of this technique in welded joints was not analyzed. The main aim of the study was to check the influence of TBW on the hardness and structures of the heat-affected zone (HAZ) of dissimilar T-jointsmade in the underwater conditions. The experiments conducted showed that the technique used can reduce the susceptibility to cold cracking by decreasing the hardness in HAZ, which is a result of changes in its structure. The TBW technique reduced the hardness in the HAZ of the S460N steel by 40–50 HV10 and in S460ML by 80–100 HV10. It was also found that the changes in S460ML and S460N were much different, and therefore, the investigated technique can provide better results in the steel characterized by lower carbon equivalent CeIIW.

  • Dissociation of furan-2-carboxylic acid by low energy electrons
    • Mateusz Zawadzki
    • J Kočišek
    • Juraj Fedor
    2020 Full text Journal of Physics : Conference Series

    Electron attachment to molecular target can lead to a variety of negative fragment ions. We experi- mentally probe the main dissociative electron attachment channels in furan-2-carboxylic acid (C3H3O2 − COOH) - a molecular target composed of two important structural units: a furan ring and a carboxylic group. In our studies we utilise nearly mono-energetic electrons at electron energies from 0 eV up to 15 eV. Our detection setup is based on extraction lens system and quadrupole mass spectrometer, that enables measurement of the energy dependent mass-selected yields of newly formed stable anions.

  • Dissociative electron attachment to benzoic acid (C7H6O2)
    • Mateusz Zawadzki
    • P. Wierzbicka
    • J. Kopyra
    2020 Full text JOURNAL OF CHEMICAL PHYSICS

    The dissociative electron attachment (DEA) to benzoic acid (C6H5COOH) has been studied using an experimental crossed beam setup of a quadrupole mass spectrometer and a trochoidal electron monochromator. Relative partial cross sections for the DEA to produce negative ion fragments show the main channels for dissociation. The comparison of the present results with the ultraviolet photoelectron spectrum of benzoic acid [J. Meeks, A. Wahlborg, and S. P. McGlynn, J. Electron Spectrosc. Relat. Phenom. 22, 43 (1981)] implies that most DEA bands in the high energy range are due to Feshbach resonances with double occupation of diffuse Rydberg-like orbitals. The measurements are supported by density functional theory calculations of the threshold energies.

  • Dissociative photo-double-ionization of the isoxazole molecules
    • Tomasz Wąsowicz
    • Antti Kivimaki
    • Robert Richter
    2020 Synchrotron Radiation in Natural Science

    The five-membered heterocyclic rings are incorporated into a wide variety of structures that play a vital role in many biochemical processes. In particular, the isoxazole molecule appears in many bioactive compounds due to its unique ring structure that consists of one oxygen atom and one nitrogen atom at adjacent positions. The unique atomic composition and bond arrangement of isoxazole imply its specific electronic properties that may be probed by diverse spectroscopic techniques, including those utilizing synchrotron radiation. In particular, the photoelectron-photoion coincidence (PEPICO) technique provides detailed information about the presence of specific bonds, the reactivity of these molecules, as well as their electronic structure and decomposition mechanisms.

  • Do Judges’ Delegations Affect Judicial Performance? A Transition Economy Evidence
    • Przemysław Banasik
    • Sylwia Morawska
    • Piotr Staszkiewicz
    • Bartosz Witkowski
    • Richard Staszkiewicz
    2020 JUSTICE SYSTEM JOURNAL

    The aim of this study is to discern whether, by delegating judges from the court to the Ministry of Justice, the Minister of Justice influences the results of courts in terms of adjudication. The study used a unique set of data for the Polish judicial system over a period of five years. The research results indicate that there are three reasons for delegating judges. Firstly, the delegation system serves to fill staff shortages among administrative staff at the Ministry of Justice. Secondly, the delegation system allows for inefficient judges to be moved. Thirdly, the system serves as an indirect control mechanism affecting the independence of courts. The results show that delegation has a positive short-term impact on judicial performance.

  • Dobór analizy strategicznej przedsięwzięć budowlanych w aspekcie zrównoważonego rozwoju
    • Maciej Niedostatkiewicz
    • Emilia Miszewska
    2020 Full text Przegląd Budowlany

    Celem artykułu jest wskazanie najbardziej właściwej z dostępnych metod analiz strategicznych dla realizacji przedsięwzięć budowlanych oraz wykorzystanie jej do oceny czy dane zamierzenie inwestycyjne pozostaje w zgodzie z zasadami rozwoju zrównoważonego.

  • Dobór geotekstyliów i wyrobów pokrewnych pełniących funkcję zbrojenia w budownictwie komunikacyjnym – wybrane problemy inżynierskie
    • Grzegorz Horodecki
    • Angelika Duszyńska
    2020

    Charakterystyka geotekstyliów i wyrobów pokrewnych stosowanych do zbrojenia gruntu w budownictwie komunikacyjnym. Identyfikacja wyrobów na budowie. Metodyka wyznaczania wytrzymałości długoterminowej zbrojenia geosyntetycznego.

  • DOBÓR PARAMETRÓW FILTRACJI W CEPSTRUM DLA POTRZEB POPRAWY JAKOŚCI ODBIERANEGO SYGNAŁU
    • Agnieszka Czapiewska
    • Andrzej Łuksza
    • Ryszard Studański
    • Andrzej Żak
    2020 Full text Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    W referacie zaproponowano metodę eliminacji wpływu efektu wielodrogowości poprzez analizę i filtrację odbieranego sygnału w cepstrum. Analiza taka, pozwala na wykrycie istnienia repliki (echa) sygnału nadawanego oraz odfiltrowanie tej repliki, co poprawia jakość realizowanej transmisji sygnału. W referacie zaprezentowano wyniki badan symulacyjnych.

  • Does the Use of Cell Phones and Headphones at the Signalised Pedestrian Crossings Increase the Risk of Accident?
    • Joanna Wachnicka
    • Karol Kulesza
    2020 Full text Baltic Journal of Road and Bridge Engineering

    Reduction of the number of fatalities among pedestrians remains a topical issue in Poland. For many years, this percentage has remained at around 30% of all those who were killed on the road. At the same time, there is an increase in the use of electronic devices by pedestrians and cyclists that may affect their perception when crossing the road. This can lead to traffic accidents. In order to investigate the problem, field studies were carried out and their results are presented in the article. Pilot studies on pedestrian and cyclist behaviour were carried out at three pedestrian crossings with traffic lights in Gdansk. Attention was paid to whether pedestrians and cyclists use headphones when crossing the road, whether they are talking on the phone or writing SMS. The results of the research indicate that currently in Gdańsk about 10% of unprotected traffic users use a telephone and 5% use headphones at pedestrian crossings. Most of them are young people, 70–90% of all users. Women prefer using headphones more than men. Pedestrians exhibited dangerous behaviour involving entering the road at a red light regardless of the use of telephones and headphones. Therefore, as part of the studies described, it cannot be clearly stated whether the use of telephones and headphones increases the risk of being the victim of an accident. Due to the lack of separate statistics with accidents involving mobile phones and headsets, it was not possible to analyse statistical data in this respect. At the same time, research confirmed traffic disruptions at the crossings, caused by telephone users, as indicated in literature.

  • Dom podcieniowy na Żuławach
    • Marta Koperska-Kośmicka
    2020

    Pozycja obowiązkowa dla sympatyków Żuław. Zawiera ponad 500 kolorowych fotografii i rycin na temat najbardziej rozpoznawalnych zabytków Delty Wisły – domów podcieniowych. To obszerne vademecum prezentuje historię oraz współczesność dawnych obiektów, przedstawiając je na tle wielobarwnej historii regionu. Oprócz tych najbardziej popularnych, książka opisuje także mniej znane domy, które dotychczas nie znalazły się na stronach albumów czy przewodników.

  • Domain Reduction in Hybrid Technique for Electromagnetic Wave Scattering Problems
    • Małgorzata Warecka
    • Piotr Kowalczyk
    • Rafał Lech
    2020 Full text

    This paper proposes a combination of the field matching technique, finite element method and generalized impedance matrix, the main idea of which is to reduce the computational domain by surrounding a scatterer with the smallest convex shape and applying the field matching technique. This approach can be applied for arbitrary shaped scatterers and types of materials and allows for the reduction of the computational domain. In order to verify the validity of the method, several examples have been investigated and compared with other numerical techniques.

  • DOMY W STANDARDZIE PASYWNYM WYTYCZNE I DOŚWIADCZENIA PROJEKTOWO-REALIZACYJNE
    • Alicja Karaś
    2020

    Tematem niniejszej publikacji są budynki mieszkalne jednorodzinne w standardzie pasywnym zgodnym z założeniami Passivhaus Institut Darmstadt – twórców idei budownictwa pasywnego. W publikacji przedstawione zostały zasady projektowania budynków pasywnych, jakimi Autorka, będąca Certyfikowanym Europejskim Projektantem Budynków Pasywnych z ramienia Passivhaus Institut Darmstadt, kieruje się na co dzień w praktyce zawodowej. Jako ilustracje poszczególnych zagadnień i zasad posłużyły projekty domów pasywnych powstałych w MIDI Pracowni Architektonicznej. Twórcami wszystkich projektów są architekci: Alicja Karaś (autorka), Piotr Karaś, Maja Belecka oraz Maria Murawska. Książka adresowana jest przede wszystkim do studentów architektury, ale również pragnących pogłębić swoją wiedzę w zakresie projektowania budynków pasywnych architektów oraz inwestorów rozważających tego rodzaju inwestycję. Publikacja zawiera szereg praktycznych wskazówek dotyczących projektowania oraz wykonawstwa.

  • Down-Sampling of Large LiDAR Dataset in the Context of Off-Road Objects Extraction
    • Wioleta Błaszczak-bąk
    • Joanna Janicka
    • Czesław Suchocki
    • Andrea Masiero
    • Anna Sobieraj-Żłobińska
    2020 Full text Geosciences

    Nowadays, LiDAR (Light Detection and Ranging) is used in many fields, such as transportation. Thanks to the recent technological improvements, the current generation of LiDAR mapping instruments available on the market allows to acquire up to millions of three-dimensional (3D) points per second. On the one hand, such improvements allowed the development of LiDAR-based systems with increased productivity, enabling the quick acquisition of detailed 3D descriptions of the objects of interest. However, on the other hand, the extraction of the information of interest from such huge amount of acquired data can be quite challenging and time demanding. Motivated by such observation, this paper proposes the use of the Optimum Dataset method in order to ease and speed up the information extraction phase by significantly reducing the size of the acquired dataset while preserving (retain) the information of interest. This paper focuses on the data reduction of LiDAR datasets acquired on roads, with the goal of extraction the off-road objects. Mostly motivated by the need of mapping roads and quickly determining car position along a road, the development of efficient methods for the extraction of such kind of information is becoming a hot topic in the research community.

  • Draft genome sequence of antimicrobial producing Paenibacillus alvei strain MP1 reveals putative novel antimicrobials
    • Magdalena Pajor
    • Jonathan Sogin
    • Randy Worobo
    • Piotr Szweda
    2020 Full text BMC Research Notes

    A Paenibacillus strain isolated in previous research exhibited antimicrobial activity against relevant human pathogens including Staphylococcus aureus and Listeria monocytogenes. In this study, the genome of the aforementioned strain, designated as MP1, was shotgun sequenced. The draft genome of strain MP1 was subject to multiple genomic analyses to taxonomically characterize it and identify the genes potentially responsible for its antimicrobial activity.

  • Drill holes decrease cancellous bone strength: A comparative study of 33 paired osteoporotic human and 9 paired artificial bone samples
    • Marcin Ceynowa
    • Krzysztof Żerdzicki
    • Paweł Kłosowski
    • Rafał Pankowski
    • Marek Rocławski
    • Tomasz Mazurek
    2020 Full text PLOS ONE

    This study was designed to compare compressive strength of cancellous bone retrieved from the femoral head in a specimen with and without guide wire hole, with comparison to synthetic bone samples. Femoral heads retrieved from 33 patients who sustained femoral neck fractures and underwent hip arthroplasty were cut into cuboids leaving two matching samples from the same femoral head. Similar samples were prepared from synthetic femurs. One of the matching samples was chosen at random and was drilled with a guide wire for cancellous screws. The uniaxial compression tests of bone blocks were carried out using the Zwick-Roell Z020 strength testing machine. The mean loss of sample cross section area due to drilling was 24%. The force at failure in drilled specimens was significantly smaller by 18% in human (median: 26%) and by 25% in synthetic bone (median 27%). The strength of human specimens was almost 2 times greater, and their stiffness nearly 4 times greater than in synthetic samples. The study shows that the weakening of the bone after drilling is roughly proportional to the loss of sample cross section area. The percentage decrease in strength was similar in human and artificial bone, but human samples were stronger and stiffer. The comparison shows that forces measured in biomechanical studies on artificial bone cannot be directly attributed to humans, but the relative differences in mechanical properties of synthetic samples after some damage may be accurate and resemble that of human bones.

  • Droga S7 Koszwały – Kazimierzowo – geotechniczne aspekty inwestycji.
    • Grzegorz Horodecki
    2020

    W artykule przedstawiono ogólne informacje dotyczące geotechnicznych aspektów projektu i realizacji drogi S7 na odcinku Koszwały – Kazimierzowo, ze szczególnym uwzględnieniem rozwiązań z zastosowaniem technologii zamkniętego materaca odciążającego z kruszywa lekkiego – keramzytu geotechnicznego. Przedstawiono metody wzmocnienia podłoża przyjęte na etapie projektu oraz realizacji wraz z monitoringiem geotechnicznym.

  • Druk 3D części z tworzyw sztucznych na skalę przemysłową w technologii SLS
    • Dawid Zieliński
    2020 Full text Materiały & Maszyny Technologiczne

    Firma EOS, wiodący i światowy dostawca technologii przemysłowego wykorzystania druku 3D dla materiałów metalicznych i polimerowych, zaprezentowała na targach formnext 2017 nowy system EOS P500, przeznaczony do addytywnego wytwarzania modeli. Drukarka 3D adresowana jest dla przedsiębiorstw chcących wytwarzać na skalę przemysłową części i elementy z tworzyw sztucznych o wysokiej jakości.