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  • A Compact Circularly Polarized Antenna With Directional Pattern for Wearable Off-Body Communications
    • Ubaid Ullah
    • Ismail Mabrouk
    • Sławomir Kozieł
    2019 Pełny tekst IEEE Antennas and Wireless Propagation Letters

    This letter presents a geometrically simple and compact circularly polarized (CP) antenna with unidirectional radiation characteristics for off-body communications. The proposed antenna is based on a microstrip line monopole extension from a coplanar waveguide (CPW) and a protruded stub from one side of the coplanar ground plane along the length of the monopole. The orthogonal components of equal amplitudes required for circular polarization are induced using the vertical stub and the horizontal edge of the coplanar ground plane. To control the radiation of the antenna towards the human body, a flexible, high permittivity laminated substrate is used as a reflector. The topological simplicity of the antenna permits a small number of adjustable variables and therefore a reduced computational cost of the parameter tuning process. The total footprint of the proposed antenna is only 0.23λ0×0.24λ0=0.05λ20 , at the lowest operating frequency. The antenna is numerically and experimentally characterized in the free-space and on a real human volunteer. The simulated and measured reflection coefficient indicates that the operating range of the antenna extends from 5.16 GHz to 6.13 GHz range with 100-percent bandwidth overlap between the impedance bandwidth and the axial ratio (AR) bandwidth. The peak gain of the antenna is 6.22 dBic with a stable radiation pattern in the +z-direction, high efficiency of 90%, and 0.131W/g SAR. The antenna can be used for Unlicensed National Information Infrastructure (U-NII) worldwide band and ISM 5.8 GHz ban

  • A COMPARISON OF WEAR PROPERTIES OF WATER LUBRICATED NBR AND PTFE SLIDING BEARINGS
    • Ewa Piątkowska
    2019 Pełny tekst TRIBOLOGIA

    The excessive wear of a journal shaft can be caused by many factors, for example, working conditions (e.g., temperaturę, slip speed, the type of lubricant), pressure, the type of material used on the bearings and shafts and their roughness, as well as contamination remaining in the system. This paper presents the roughness profiles co-operating with a rubber (NBR) and polytetrafluoroethylene (PTFE) bushes. The conditions of cooperation between the two materials tested in the sliding combination with the stainless steel journal were the same in each pair of bearings (PV); therefore, the comparison of their wear depends only on the material properties of the bush and the deformation of the journal shaft caused by the bending moment. To assess the size of the journal shaft, they were tested using a profilograph. In addition to the journal shaft, bearings were also evaluated, the wear level of which was noticed without the use of specialized equipment.

  • A comprehensive approach to double inverted pendulum modelling
    • Kamil Andrzejewski
    • Mateusz Czyżniewski
    • Maciej Zielonka
    • Rafał Łangowski
    • Tomasz Zubowicz
    2019 Pełny tekst Archives of Control Sciences

    The problem of mathematical modelling and indication of properties of a DIP has been investigated in this paper. The aim of this work is to aggregate the knowledge on a DIP modelling using the Euler-Lagrange formalism in the presence of external forces and friction. To indicate the main properties important for simulation, model parameters identification and control system synthesis, analytical and numerical tools have been used. The investigated properties include stability of equilibrium points, a chaos of dynamics and non-minimum phase behaviour around an upper position. The presented results refer to the model of a physical (constructed) DIP system.

  • A Computationally Efficient Model for Predicting Successful Memory Encoding Using Machine-Learning-based EEG Channel Selection
    • Krishnakant Saboo
    • Yogatheesan Varatharajah
    • Brent M. Berry
    • Michael R. Sperling
    • Richard Gorniak
    • Kathryn A. Davis
    • Barbara C. Jobst
    • Robert E. Gross
    • Bradley C. Lega
    • Sameer A. Sheth
    • Michael J. Kahana
    • Michał Tomasz Kucewicz
    • Gregory A. Worrell
    • Ravishankar K Iyer
    2019 IEEE ENGINEERING IN MEDICINE AND BIOLOGY MAGAZINE

    Computational cost is an important consideration for memory encoding prediction models that use data from dozens of implanted electrodes. We propose a method to reduce computational expense by selecting a subset of all the electrodes to build the prediction model. The electrodes were selected based on their likelihood of measuring brain activity useful for predicting memory encoding better than chance (in terms of AUC). A logistic regression prediction model was built using spectral features of intracranial electroencephalography (iEEG) from the selected electrodes. We demonstrate our method on iEEG data from 37 human subjects performing free recall verbal short-term memory tasks. The method achieves a 36.3% reduction in the number of electrodes used for prediction, resulting in a 64.9% reduction in inference computation time with just a 0.3% loss in prediction performance compared to the case when all electrodes were used. The electrodes selected using our method provided improved prediction performance compared to those electrodes that were not selected in 31 out of 37 patients. Building upon this observation, we also developed a method to identify the subjects for whom the proposed electrode selection method would be beneficial.

  • A CONCEPT DESIGN OF DIESEL – HYDRAULIC PROPULSION SYSTEM FOR PASSENGER SHIP INTENDED FOR INLAND SHALLOW WATER NAVIGATION
    • Czesław Dymarski
    2019 Pełny tekst Polish Maritime Research

    This paper presents an analysis of environmental and technical conditions necessary for working out a possibly most favourable propulsion system for a two – segment passenger ship intended for navigation between Berlin and Kaliningrad. There are presented various types of propulsion systems for small ships as well as analyzed their possible applications and consequences. In this work there were taken into account system’s reliability, efficiency, dimensions, mass and costs of manufacturing, assembling and possible replacing the system components as well as an impact on maneuverability and natural environment. With taking into account the above mentioned criteria it was finally found that the diesel-hydraulic system fitted with two azimuthal ducted solid propellers is the most favourable. There are also presented a schematic propulsion and control diagram, three-dimensional arrangement drawing of system components as well as assembly drawing of the designed azimuthal propulsion system.

  • A Concept of Automatic Film Color Grading Based on Music Recognition and Evoked Emotions
    • Dawid Weber
    • Bożena Kostek
    2019

    The article presents the aspects of the final selection of the color of shots in film production based on the psychology of color. First of all, the elements of color processing, contrast, saturation or white balance in the film shots were presented and the definition of color grading was given. In the second part of the article the analysis of film music was conducted in the context of stimulating appropriate emotions while watching the film. Objective parameters of the color of the shot have been defined as well as low and high-level parameters of the analysis of musical compositions, which will allow to study the mood in the soundtrack. Finally, a concept of color grading system working on machine learning based on emotion detection in the soundtrack was proposed.

  • A concept of software extension of 3D low-PRF radar systems to 4D semi-medium-PRF radar systems
    • Michał Meller
    • Kamil Stawiarski
    2019 Pełny tekst Proceedings of SPIE

    We present a concept of software modification of three-dimensional (3D) radar systems, designed to work in the low pulse repetition frequency mode, that equips them with the ability to estimate the radial velocity and to properly measure the range of targets that are detected outside the radar’s instrumented range. Despite the fact that the proposed modifications are designed so as to require only minor changes in software, they offer significant growth in the system capabilities. The modified system may potentially work in the medium pulse repetition frequency mode as a so-called four-dimensional (4D) system. The proposed Doppler velocity estimation algorithm is presented in details as well.

  • A correlation between electron-hole pair radii and magnetomodulation of exciplex fluorescence in electron donor-electron acceptor organic systems
    • Daniel Karol Pelczarski
    • Piotr Jerzy Grygiel
    • Karol Falkowski
    • Waldemar Stampor
    2019 Pełny tekst APPLIED PHYSICS LETTERS

    Electric field dependencies of electromodulated photoluminescence and magnitudes of the magnetic-field effect on photoluminescence havebeen measured in vacuum-evaporated films of m-MTDATA [4,4',4"-tris(N-(3-methylphenyl)-N-phenylamino)triphenylamine]:bathophe-nanthroline, m-MTDATA:BCP (bathocuproine), as well as 4,4',4"-tris[2-naphthyl(phenyl)amino]triphenylamine:BCP. The Sano-Tachiya-Noolandi-Hong extension of standard Onsager formalism was used to investigate the electron-hole pair dissociation process which allowedus to estimate the pair intercarrier distances and the final speed of carrier recombination. A distinct correlation between the pair radii andthe magnitude of the magnetic-field effect has been found.

  • A Cu/Zn heterometallic complex with solvent-binding cavity, catalytic activity for the oxidation of 1-phenylethanol and unusual magnetic properties
    • Agnieszka Mielcarek
    • Alina Bieńko
    • Paulina Saramak
    • Julia Jezierska
    • Anna Dołęga
    2019 DALTON TRANSACTIONS

    Mononuclear and polymeric complexes of zinc(II) and copper(II) have been synthesized using two isomers of the hemi-salen ligand with a different mutual orientation of donor atoms. The heterometallic Cu/Zn metallocycle features a catalytic niche filled with the molecule of water and molecules of methanol. This unusual compound exhibits both pronounced catalytic activity in the reaction of oxidation of a secondary alcohol to ketone and field induced slow magnetic relaxation, which is a very rare phenomenon among Cu(II) complexes.

  • A design framework for rigorous constrained EM-driven optimization of miniaturized antennas with circular polarization
    • Adrian Bekasiewicz
    • Sławomir Kozieł
    2019 Pełny tekst Metrology and Measurement Systems

    Compact radiators with circular polarization are important components of modern mobile communication systems. Their design is a challenging process which requires maintaining simultaneous control over several performance figures but also the structure size. In this work, a novel design framework for multi-stage constrained miniaturization of antennas with circular polarization is presented. The method involves sequential optimization of the radiator in respect of selected performance figures and, eventually, the size. Optimizations are performed with iteratively increased number of design constraints. Numerical efficiency of the method is ensured using a fast local-search algorithm embedded in a trust-region framework. The proposed design framework is demonstrated using a compact planar radiator with circular polarization. The optimized antenna is characterized by a small size of 271 mm2 with 37% and 47% bandwidths in respect of 10 dB return loss and 3 dB axial ratio, respectively. The structure is benchmarked against the state of-the-art circular polarization antennas. Numerical results are confirmed by measurements of the fabricated antenna prototype.

  • A fast start-up of the organotrophic anammox process inoculated with constructed wetland sediment
    • Xuejiao Yin
    • Jun Zhai
    • Wei Hu
    • Yue Li
    • Md. Hasibur Rahaman
    • Jacek Mąkinia
    2019 ECOLOGICAL ENGINEERING

    Organotrophic anaerobic ammonium oxidation (anammox) bacteria can utilize small volatile fatty acids with nitrate as electron acceptors with less energy consumption and no biomass production. To achieve a faster and stable start-up of organotrophic anammox process, in this study, the growth of organotrophic anammox bacteria seeded from hybrid constructed wetland (CW) sediment under different TOC/TN ratios and different chloramphenicol concentrations were investigated. The incubation study was conducted at the TOC/TN ratio = 0.0375–0.1 or 0.1–0.2 for the period of over five months by using serum bottles. The anammox bacteria revealed a higher activity when the TOC/TN ratio was 0.1, with the removal efficiency of NH4+-N (60–80%) and NO2−-N (~100%). The relative abundances of anammox in the incubated CW sediment were about 30% higher in comparison with the municipal waste water treatment plant sludge, suggesting the CW sediment could be a viable source for the enrichment of organotrophic anammox bacteria. On the contrary, the continuous addition of 50 mg/L chloramphenicol completely inhibited the anammox activity in our study. Following the results of the batch tests, Candidatus Brocadia caroliniensis was successfully enriched with the CW sediment in an auto-controlled SBR for the period of 40 days.

  • A Framework for Searching in Graphs in the Presence of Errors
    • Dariusz Dereniowski
    • Stefan Tiegel
    • Przemysław Uznański
    • Daniel Wolleb-Graf
    2019

    We consider a problem of searching for an unknown target vertex t in a (possibly edge-weighted) graph. Each vertex-query points to a vertex v and the response either admits that v is the target or provides any neighbor s of v that lies on a shortest path from v to t. This model has been introduced for trees by Onak and Parys [FOCS 2006] and for general graphs by Emamjomeh-Zadeh et al. [STOC 2016]. In the latter, the authors provide algorithms for the error-less case and for the independent noise model (where each query independently receives an erroneous answer with known probability p<1/2 and a correct one with probability 1-p). We study this problem both with adversarial errors and independent noise models. First, we show an algorithm that needs at most (log_2 n)/(1 - H(r)) queries in case of adversarial errors, where the adversary is bounded with its rate of errors by a known constant r<1/2. Our algorithm is in fact a simplification of previous work, and our refinement lies in invoking an amortization argument. We then show that our algorithm coupled with a Chernoff bound argument leads to a simpler algorithm for the independent noise model and has a query complexity that is both simpler and asymptotically better than the one of Emamjomeh-Zadeh et al. [STOC 2016]. Our approach has a wide range of applications. First, it improves and simplifies the Robust Interactive Learning framework proposed by Emamjomeh-Zadeh and Kempe [NIPS 2017]. Secondly, performing analogous analysis for edge-queries (where a query to an edge e returns its endpoint that is closer to the target) we actually recover (as a special case) a noisy binary search algorithm that is asymptotically optimal, matching the complexity of Feige et al. [SIAM J. Comput. 1994]. Thirdly, we improve and simplify upon an algorithm for searching of unbounded domains due to Aslam and Dhagat [STOC 1991].

  • A Generalized Framework Towards Structural Mechanics of Three-layered Composite Structures
    • Marcus Aßmus
    • Konstantin Naumenko
    • Andreas Öchsner
    • Victor Eremeev
    • Holm Altenbach
    2019 Pełny tekst Technische Mechanik

    Three-layered composite structures find a broad application. Increasingly, composites are being used whose layer thicknesses and material properties diverge strongly. In the perspective of structural mechanics, classical approaches to analysis fail at such extraordinary composites. Therefore, emphasis of the present approach is on arbitrary transverse shear rigidities and structural thicknesses of the individual layers. Therewith we employ a layer-wise approach for multiple (quasi-)homogeneous layers. Every layer is considered separately whereby this disquisition is based on the direct approach for deformable directed surfaces. We limit our considerations to geometrical and physical linearity. In this simple and familiar setting we furnish a layer-wise theory by introducing constraints at interfaces to couple the layers. Hereby we restrict our concern to surfaces where all material points per surface are coplanar and all surfaces are plane parallel. Closed-form solutions of the governing equations enforce a narrow frame since they are strongly restrictive in the context of available boundary conditions. Thus a computational solution approach is introduced using the finite element method. In order to determine the required spatially approximated equation of motion, the principle of virtual work is exploited. The discretization is realized via quadrilateral elements with quadratic shape functions. Hereby we introduce an approach where nine degrees of freedom per node are used. In combination with the numerical solution approach, this layer-wise theory has emerged as a powerful tool to analyze composite structures. In present treatise, we would like to clarify the broad scope of this approach.

  • A Generalized SDP Multi-Objective Optimization Method for EM-Based Microwave Device Design
    • Liu Ying
    • Qingsha Cheng
    • Sławomir Kozieł
    2019 Pełny tekst SENSORS

    In this article, a generalized sequential domain patching (GSDP) method for efficient multi-objective optimization based on electromagnetics (EM) simulation is proposed. The GSDP method allowing fast searching for Pareto fronts for two and three objectives is elaborated in detail in this paper. The GSDP method is compared with the NSGA-II method using multi-objective problems in the DTLZ series, and the results show the GSDP method saved computational cost by more than 85% compared to NSGA-II method. A diversity comparison indicator (DCI) is used to evaluate approximate Pareto fronts. The comparison results show the diversity performance of GSDP is better than that of NSGA-II in most cases. We demonstrate the proposed GSDP method using a practical multi-objective design example of EM-based UWB antenna for IoT applications.

  • A Geometrically Simple Compact Wideband Circularly Polarized Antenna
    • Ubaid Ullah
    • Sławomir Kozieł
    • Ismail Mabrouk
    2019 IEEE Antennas and Wireless Propagation Letters

    A compact broadband wide-slot circular polarization (CP) antenna is proposed. An inverted L-shape parasitic strip at the open end of a microstrip line extension and a slot modification is applied to attain wideband CP. The advantage of this technique is simplicity which makes it readily re-designable for different frequency bands. To demonstrate the concept, three designs working at different frequencies are obtained. The redesign procedure is straightforward and only requires a recalculation of the selected physical dimensions followed by EM-based parameter tuning. A compact size of 0.09λ0 is achieved when measured at the lowest CP frequency. The optimized designs are validated experimentally in terms of |S11| , axial ratio (AR), realized gain, and radiation patterns. For the design corresponding to the lowest operating frequency, a total impedance bandwidth of ∼89-percent (3.2 GHz- 8.4 GHz), ARBW ≤3dB of 82-percent (3.2 GHz to 7.65 GHz), average in-band realized gain of 3.3 dBi, and a bidirectional radiation pattern with a dual sense of polarization is achieved. A thorough benchmarking indicates the superiority of the proposed antenna over the state-of-the-art designs in terms of all major performance figures.

  • A Highly Selective Biosensor Based on Peptide Directly Derived from the HarmOBP7 Aldehyde Binding Site
    • Wasilewski Tomasz
    • Bartosz Szulczyński
    • Marek Wojciechowski
    • Wojciech Kamysz
    • Jacek Gębicki
    2019 Pełny tekst SENSORS

    This paper presents the results of research on determining the optimal length of a peptide chain to eectively bind octanal molecules. Peptides that map the aldehyde binding site in HarmOBP7 were immobilized on piezoelectric transducers. Based on computational studies, four Odorant Binding Protein-derived Peptides (OBPPs) with dierent sequences were selected. Molecular modelling results of ligand docking with selected peptides were correlated with experimental results. The use of low-molecular synthetic peptides, instead of the whole protein, enabled the construction OBPPs-based biosensors. This work aims at developing a biomimetic piezoelectric OBPPs sensor for selective detection of octanal. Moreover, the research is concerned with the ligand binding anity depending on dierent peptides’ chain lengths. The authors believe that the chain length can have a substantial influence on the type and eectiveness of peptide–ligand interaction. A confirmation of in silico investigation results is the correlation with the experimental results, which shows that the highest anity to octanal is exhibited by the longest peptide (OBPP4 – KLLFDSLTDLKKKMSEC-NH2). We hypothesized that the binding of long chain aldehydes to the peptide, mimicking the binding site of HarmOBP7, induced a conformational change in the peptide deposited on a selected transducer. The constructed OBPP4-based biosensors were able to selectively bind octanal in the gas phase. It was also shown that the sensors were characterized by high selectivity with respect to octanal, as well as to acetaldehyde and benzaldehyde. The results indicate that the OBPP4 peptide, mimicking the binding domain in the Odorant Binding Protein, can provide new opportunities for the development of biomimicking materials in the field of odor biosensors.

  • A hybrid model of flooding of the ro-ro ships in damaged conditions
    • Mirosław Gerigk
    • Jacek Jachowski
    • Julita Sargun
    2019 Pełny tekst TransNav - The International Journal on Marine Navigation and Safety of Sea Transportation

    The paper presents some results on investigations concerning development of a hybrid model for assessment of performance of the ro‐ro ships in damaged conditions. The model is devoted towards assessing the performance of the damaged ro‐ro ships at the preliminary stage of design. The key problems associated with preparing of such the model are associated with working out a method of assessment of the damaged roro ships performance, investigating all the phenomena which associated with the flooding process of the damaged ro‐ro ships and preparing the model itself. Introducing the method of assessment of the damaged roro ships performance it has been assumed that there is a dependence between the arrangement of internal spaces of a ro‐ro ship and flooding process. The major phenomena which have been decided to take into account when considering flooding of the ro‐ro ships are the flooding understood as the flow of external water into the data damaged compartment, impact of the flooding water on the ship structure and damaged ro‐ro ship motion. Knowing the damaged ro‐ro ship motion characteristics in time domain it is relatively easy to assess the damaged ro‐ro ship performance according to the heeling angle and assess the ro‐ro ship design according to the data arrangement of internal spaces. The last research issue is to investigate if the proposed model may be appropriate tool for assessing the performance of the ro‐ro ships in damaged conditions at the preliminary stage of design. The aim of this paper is to show how to incorporate the dynamics of the damaged ro‐ro ships when assessing the ship performance and safety at the preliminary stage of design. The basic information on the model for estimation of the damaged ro‐ro ship behavior during the flooding process is presented. The complexity of this model is shown depending on the approach applied to consider the flooding process itself. The model is devoted towards assessment of performance of the damaged ro‐ro ships and it is still under the development according to a Ph.D. research at the Faculty of Mechanical Engineering Gdańsk University of Technology.

  • A Measurement System for Quasi-Spectral Determination of Absorption and Scattering Parameters of Veterinary Tissue Phantoms
    • Paulina Listewnik
    • Michał Wąsowicz
    • Monika Kosowska
    • Adam Mazikowski
    2019 Pełny tekst Applied Sciences-Basel

    This paper describes the construction of a system for the quasi-spectral determination of absorption and scattering parameters of animal tissue phantoms. Several tissue phantoms, including one reference and two modified for examination, were prepared from polydimethylsiloxane (PDMS). The phantoms were measured using a system based on an integrating sphere and the light sources of wavelengths commonly used for the treatment of various diseases in veterinary medicine, including 635 nm (red), 532 nm (green) and 447 nm (blue). The obtained results are consistent with data provided in reference sources and can also be approximated for the entire spectral range of visible radiation (380–780 nm). The developed system is suitable for further measurements of phantoms, which can be adapted to imitate different tissues.

  • A Method for Determination and Compensation of a Cant Influence in a Track Centerline Identification Using GNSS Methods and Inertial Measurement
    • Władysław Koc
    • Cezary Specht
    • Jacek Szmagliński
    • Piotr Chrostowski
    2019 Pełny tekst Applied Sciences-Basel

    At present, the problem of rail routes reconstruction in a global reference system is increasingly important. This issue is called Absolute Track Geometry, and its essence is the determination of the axis of railway tracks in the form of Cartesian coordinates of a global or local coordinate system. To obtain such a representation of the track centerline, the measurement methods are developed in many countries mostly by the using global navigation satellite system (GNSS) techniques. The accuracy of this type of measurement in favorable conditions reaches one centimeter. However, some specific conditions cause the additional supporting measurements with a use of such instruments as tachymetry, odometers, or accelerometers to be needed. One of the common issues of track axis reconstruction is transforming the measured GNSS antenna coordinates to the target position, i.e., to the place between rails on the level of rail heads. The authors in their previous works described the developed methodology, while this article presents a method of determining the correction of horizontal coordinates for measurements in arc sections of the railway track. The presence of a cant causes the antenna’s center to move away from the track axis, and for this reason, the results must be corrected. This article presents a method of calculation of mentioned corrections for positions obtained from mobile satellite surveying with additional inertial measurement. The algorithm presented in the article and its implementation have been illustrated on an example of a complex geometric layout, where cant transitions exist without transition curves in horizontal plane. Such a layout is not preferable due to the additional accelerations and their changes. However, it allows the verification of the presented methods.

  • A Method for the Evaluation of Urban Freight Transport Models as a Tool for Improving the Delivery of Sustainable Urban Transport Policy
    • Daniel Kaszubowski
    2019 Pełny tekst Sustainability

    The article presents a method which helps local authorities to evaluate urban freight transport models. Given the complex requirements for input data and the inability to supply them for most cities, a proper quantitative evaluation of model functionality may be quite difficult for local authorities. Freight transport models designed to support sustainable urban freight transport objectives are a particular example. To overcome these difficulties, the structure of the method is based on a qualitative analysis of strategic and operational conditions of urban freight management for modelling purposes. A consistent set of criteria is developed to help with parameterising strategic objectives and the analytical requirements of tools to achieve those objectives. The problems of data availability and capture are also included. The method consists of three tiers that are arranged hierarchically to reflect the interrelations. The proposed method was verified against Gdynia’s (Poland) urban freight management requirements. The city was chosen for its early experience of urban freight studies and improvement measures and because it has already defined its strategic objectives. Two comprehensive freight transport models (Freturb and Wiver) and existing city’s transport model were evaluated. The results have ruled out the existing transport model rendering it ineffective as a tool to support urban freight management to meet the city’s strategic objectives. While Freturb turned out to be much better suited for the needs, dedicated models still face a basic barrier of cities having to redesign their systems for collecting urban transport data

  • A method for the three-dimensional and synchronous resolution of functional and spatial matters in architectural design
    • Ksenia Piątkowska
    2019 Pełny tekst World Transactions on Engineering and Technology Education

    The article discusses the issue of applied methods of teaching architectural design at Polish universities. The authors review the common methods based on conceptual drawings solving design problems in only two dimensions. After completing the floor plans' sketching process carried out in 2D way the 3D virtual models are made - seldom cardboard mock-ups - to illustrate the final spatial form of the designed object. At the Faculty of Architecture of Gdansk University of Technology the method of building an architectural concept is based on simultaneous analysis of spatial structure, functional connections and utility assumptions in three dimensions, by testing all the ideas in the mock-up structures first to find the adequate solutions for a particular context of the design. As the second stage of the design process the traditional methods of 2D design are implemented to conclude the architectural task. This process of building an architectural concept first in 3D mock-ups shapes students' spatial imagination - a desired ability in the architect's profession.

  • A Method of Fast and Simultaneous Calibration of Many Mobile FMCW Radars Operating in a Network Anti-Drone System
    • Aleksander Nowak
    • Krzysztof Naus
    • Dariusz Maksimiuk
    2019 Pełny tekst Remote Sensing

    A market for small drones is developing very fast. They are used for leisure activities and exploited in commercial applications. However, there is a growing concern for accidental or even criminal misuses of these platforms. Dangerous incidents with drones are appearing more often, and have caused many institutions to start thinking about anti-drone solutions. There are many cases when building stationary systems seems to be aimless since the high cost does not correspond with, for example, threat frequency. In such cases, mobile drone countermeasure systems seem to perfectly meet demands. In modern mobile solutions, frequency modulated continuous wave (FMCW) radars are frequently used as detectors. Proper cooperation of many radars demands their measurements to be brought to a common coordinate system—azimuths must be measured in the same direction (preferably the north). It requires calibration, understood as determining constant corrections to measured angles. The article presents the author's method of fast, simultaneous calibration of many mobile FMCW radars operating in a network. It was validated using 95,000 numerical tests. The results show that the proposed method significantly improves the north orientation of the radars throughout the whole range of the initial errors. Therefore, it can be successfully used in practical applications.

  • A method to determine the tightening sequence for standing rigging of a mast
    • Leszek Samson
    • Maciej Kahsin
    2019 Pełny tekst Polish Maritime Research

    The article proposes an alternative method to determine the sequence of generation of pre-tension forces in standing rigging of a mast. The proposed approach has been verified on both a virtual simulation experiment and laboratory tests. In this method, the desired tension values are obtained using the influence matrix which allows to calculate the effect of tension change in an individual rope on the tension distribution in the remaining ropes in the system. Unlike the presently used method, in which the desired tension distribution is obtained in a long-lasting iterative process burdened with relatively large errors of final values, the proposed method makes it possible to achieve the final tension distribution in a finite number of steps. In the case of FEM analyses, the new method can be a useful tool for determining an arbitrary distribution of tension forces in ropes via solving a system of linear equations.

  • A miniaturized solid-contact potentiometric multisensor platform for determination of ionic profiles in human saliva
    • Marcin Urbanowicz
    • Dorota G. Pijanowska
    • Artur Jasiński
    • Marcin Ekman
    • Maria Bocheńska
    2019 Pełny tekst JOURNAL OF SOLID STATE ELECTROCHEMISTRY

    This paper describes a miniaturized multisensor platform (MP-ISES) consisting of electrodes: a reference one (RE) and ion-selective electrodes (ISEs) for monitoring Na+, K+, Ca2+, Mg2+, Cl−, and SCN− ions and pH in human saliva. Gold electrode surface was modified by deposition of two layers: electrosynthesized PEDOT:PSS forming an intermediate layer, and ion-selective membrane. The developed ISEs were characterized by a wide linear range and sensitivity consistent with the Nernst model. The entire MP-ISEs are characterized by satisfactory metrological parameters demonstrating their applicability in biomedical research, in particular in measurements concerning determination of ionic profiles of saliva. Saliva samples of 18 volunteers aged from 20 to 26 participating in a month experiment had been daily collected and investigated using the MP-ISEs assigned individually to each person. Personalized profiles of ions (ionograms) in saliva, such as Na+, K+, Ca2+, Mg2+, Cl−, SCN−, and H+, were obtained.

  • A mixture of cellulose production waste with municipal sewage as new material for an ecological management of wastes
    • Jacek Antonkiewicz
    • Agnieszka Baran
    • Robert Pełka
    • Anna Wisła-Świder
    • Ewelina Nowak
    • Piotr Konieczka
    2019 ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY

    Chemical contaminants present in cellulose production waste and municipal sewage sludge condition the necessity to treat these wastes before they are introduced into the environment. Environmental use of the these wastes appears to be justified owing to the content of organic substances as well as the considerable fertilising value. The aim of the study was to assess chemical composition and ecotoxicity of cellulose production waste and municipal sewage sludge in terms of their eco-friendly application. The assessment was done based on the established soil environment according to regulations in Poland. The research on the chemical composition of the wastes was conducted under laboratory conditions, determining the content of macroelements, microelements and heavy metals with respect to using these wastes in the environment. Phytotoxkit and Microtox tests were performed in order to determine the ecotoxicity of the wastes in the aspect of their environmental use. It was established that, compared to the cellulose production waste, the municipal sewage sludge used in the incubation experiment had a higher content of macroelements and microelements. The content of heavy metals in the waste did not exceed the permissible content that conditions their use in agriculture and reclamation. Based on the results of bioassays it was established that the cellulose production waste was toxic, whereas the combination of cellulose production waste and sewage sludge was found to be of low toxicity to test organisms. The applied wastes and their mixtures were ranked according to phytotoxicity in the following order: cellulose production waste> cellulose production waste +soil> cellulose production waste +sewage sludge. The research results indicate that waste mixtures qualify for environmental use. With respect to the variable chemical composition of cellulose production waste and municipal sewage sludge as well as their ecotoxicity, it was established that each batch intended for environmental use must be subjected to chemical analysis and ecotoxicological tests.

  • A model development and experimental verification for a vapour microturbine with a permanent magnet synchronous generator
    • Wojciech Włodarski
    2019 Pełny tekst APPLIED ENERGY

    Vapour microturbines with permanent magnet synchronous generators are implemented in micropower plants for dispersed power generation systems. The dynamic model of such a microturbine set was developed and presented. The developed relations result from the generic equations. Experimental data for two different working medium were used for model verification. A microturbine set model was tested during the changes in the parameters of a working medium or an electrical load. Examples of a comparison between the experimental results and simulations are shown and discussed. The developed model ensures comparable accuracy as gas microturbine models found in the literature. In the case of vapour microturbine sets, in addition to accuracy, provides a larger area of operation. An operation during a start-up process was also analysed. Due to model simplifications, the accuracy decreases for a start-up operation from a cold state. The developed model can be a useful tool for some engineering applications or for studying the various operational aspects of vapour microturbines with permanent magnet synchronous generators.

  • A Multi-Antenna Scheme for Early Detection and Mitigation of Intermediate GNSS Spoofing
    • Jarosław Magiera
    2019 Pełny tekst SENSORS

    This article presents a method for detecting and mitigating intermediate GNSS spoofing. In this type of attack, at its early stage, a spoofer transmits counterfeit signals which have slight time offsets compared to true signals arriving from satellites. The anti-spoofing method proposed in this article fuses antenna array processing techniques with a multipath detection algorithm. The latter is necessary to separate highly correlated true and counterfeit GNSS signals. Spoofing detection is based on comparison of steering vectors related to received spatial components. Whereas mitigation is achieved by means of adaptive beamforming which excises interferences arriving from common direction and preserves undistorted signals from GNSS satellites. Performance of proposed method is evaluated through simulations, results of which prove the usefulness of this method for protecting GNSS receivers from intermediate spoofing interference.

  • A negative effect of carbon phase on specific capacity of electrode material consisted of nanosized bismuth vanadate embedded in carbonaceous matrix
    • Andrzej Nowak
    • Konrad Trzciński
    • Mariusz Szkoda
    • Jakub Karczewski
    • Maria Gazda
    • Anna Lisowska-Oleksiak
    2019 Pełny tekst SYNTHETIC METALS

    Lithium-ion batteries (LIBs) are widely used all over the world. The LIBs belong to a renewable energy source and energy storage devices. The increase in energy demand causes that new materials of higher energy and higher power densities are still under investigation. Herein, we compare electrochemical properties of bismuth vanadate (BiVO4) embedded and not embedded into carbonaceous matrix as an anode material along with structural changes. Material incorporated into carbon phase (BiVO4@C) exhibited much better electrochemical stability but with lower specific capacity (128 mA h/g) in comparison with pure BiVO4 (217 mA h/g). XRD measurements showed the change in crystallographic structure due to lithium ion intercalation/extraction process. Hence, it seemed obvious that the presence of carbon affected the interfacial structural and electrochemical properties of bismuth vanadate based electrodes.

  • A New Approach for Investigating the Impact of Pesticides and Nutrient Flux from Agricultural Holdings and Land-Use Structures on Baltic Sea Coastal Waters
    • Lidia Dzierzbicka-Głowacka
    • Maciej Janecki
    • Dawid Dybowski
    • Beata Szymczycha
    • Hanna Obarska-Pempkowiak
    • Ewa Wojciechowska
    • Piotr Zima
    • Stefan Pietrzak
    • Grażyna Pazikowska-sapota
    • Beata Jaworska-Szulc
    • Artur Nowicki
    • Żaneta Kłostowska
    • Adam Szymkiewicz
    • Katarzyna Galer-Tatarowicz
    • Marcin Wichorowski
    • Michał Białoskórski
    • Tadeusz Puszkarczuk
    2019 Pełny tekst POLISH JOURNAL OF ENVIRONMENTAL STUDIES

    Knowledge related to land-use management impacts on the Baltic Sea ecosystem is limited. The constant release of pollutants into water bodies has resulted in water quality degradation. Therefore, only the innovative approaches integrated with research will provide accurate solutions and methods for proper environment management and will enable understanding and prediction of the impacts of land-use in the Baltic Sea region. Modelling approaches have become essential to address water issues and to evaluate ecosystem management. There are many water quality models, but only a few work in the operational mode and only some of them can be used as an interactive tool for environmental management to assess the impact of pollution on water quality. This study presents a new approach for investigating the influence of pesticides and nutrient fluxes from agricultural holdings and land-use structures on coastal waters of the Baltic Sea. Called WaterPUCK, this method will enable calculation of the sufficient amount of fertilizers, investigation nutrients, and pesticide sources and model: the fate and distribution of nutrients and pesticides in the surface water and groundwater; loads of pollution to surface water and groundwater; fluxes of nutrients via submarine groundwater discharge (SGD) to the Baltic Sea coastal environment; the processes and mechanisms influencing the persistence of nutrients in the environment; and predict the changes in land use and climate change influence on the Bay of Puck ecosystem.

  • A new dilution-enrichment sample preparation strategy for expanded metabolome monitoring of human breast milk that overcomes the simultaneous presence of low- and high-abundance lipid species
    • Weronika Hewelt-Belka
    • Dorota Garwolińska
    • Mariusz Belka
    • Tomasz Bączek
    • Jacek Namieśnik
    • Agata Kot-Wasik
    2019 FOOD CHEMISTRY

    The complex nature of human breast milk (HBM) makes samples difficult to analyze, requiring several extraction techniques and analytical platforms to obtain high metabolome coverage. In this work, we combined liquid-liquid extraction (LLE) and solid-phase extraction (SPE) techniques to prepare HBM samples to overcome the challenge of low- and high-abundance lipid species, enabling the semiquantitative analysis of total HBM lipids in one liquid chromatography-mass spectrometry (LC-MS) run. A nonorganic fraction obtained during the LLE step was used to analyze small polar metabolites. This analytical approach allows extensive metabolome coverage, especially for low-abundance glycerophospholipids and sphingolipids. The method was applied to monitor short-term metabolome changes in HBM composition within individual mothers and the results showed variable metabolite composition patterns. Simultaneous detection of high-abundance glycerolipids and low-abundance but not less significant phospholipids in one LC-MS run saves time, decreases cost, and enables comprehensive insight into the dynamics of HBM composition.

  • A New Geodetic Method of Examination of Geometrical Conditions of a Crane Bridge
    • Daria Filipiak-Kowszyk
    • Waldemar Kamiński
    • Karolina Makowska
    2019 Pełny tekst Geosciences

    Safety is one of the key aspects related to crane-based material transport. In order to ensure safe crane operation and material transport, it is necessary to meet certain geometrical conditions. The authors addressed the geometrical conditions of a crane bridge, a substantial crane component. The paper presents the method to compute displacement components of points on the top of a bridge crane relative to their design position. Theoretical considerations presented in the paper have been verified on simulated data. Keeping in mind the proper operation of a crane bridge, the authors proposed in the analyses the use of geometrical relations (perpendicular and parallel character) between end carriages and girders, not previously included in the available literature. The obtained results show that the presented method may be successfully applied to check the geometry of a crane bridge.

  • A NEW MASTER'S DEGREE PROGRAM IN GEODESY
    • Paweł Wysocki
    • Dominika Wróblewska
    2019

    Faculty of Civil and Environmental Engineering (WILiS) at Gdansk University of Technology (GUT) offers studies in the fields of Geodesy and Cartography. The bachelor program (7 semesters) was started ten years ago in 2009. It provides the student with the basic skills and knowledge in the fields of surveying, geodesy and more generally geomatics and cartography. It is strongly related to expertise knowledge of civil building (geodetic monitoring systems) and environmental engineering (photogrammetry and laser detection). During 2014 - 2017 years students were able to continue studying at postgraduate course and get MSc degree at Surveying Techniques in Engineering, an inter-faculty course. The observation of the labour market requirements indicated the need for graduates prepared to solve specific knowledge enabling solving engineering problems and with wide set of soft skills. As a response, a new master degree program in the field of geodesy and cartography was prepared and started in 2017 in specialization of geomatics and geoinformatics. This studies prepare the graduate for employment in surveying and research companies with interdisciplinary knowledge and a special focus on geomatics and geoinformatics or photogrammetry and remote sensing. The curriculum is also prepared to enable graduates to gain professional qualifications in the field of photogrammetry and remote sensing. The article presents objectives, structure and contents of a new master degree level studies and its relation to the labour qualifications and research conducted by academic teachers employed in Department of Geodesy

  • A new method and equipment for the detection of presence and estimation of the content of the petroleum-based fraction in lubricating oils, especially those emitted to the atmosphere
    • Paulina Nowak
    • Marian Antoni Kamiński
    • Piotr Rybarczyk
    • Karolina Kucharska
    2019 Aparatura Badawcza i Dydaktyczna

    Lubricating oil, used in cutting equipment, works in the so-called open lubrication system and is entirely emitted to the environment. When such an oil contains even a small portion of the crude oil-derived fraction, which is still very common, the oil is a serious environmental pollution. In addition, the oil mist poses a serious threat to the health of employees. Current legal regulations require users of saws and harvesters to use only biodegradable oils. In the case of hydraulic oils used in machines and vehicles, there is always a risk of leakage into the environment e.g. in case of breakage of connecting pipes or other types of breakdowns. Therefore, it seems reasonable to postulate the use of biodegradable oils in power hydraulics systems of machines used in forests, fields, mines or in rail or road vehicles. Bio-degradable oil, most often, with base vegetable oil, is more expensive than lubricating oil produced with the use of an oil-based oil base – i.e. a product of oil refining. Today, users of saws and harvesters still use mineral lubricating oils from crude oil, without any attention to the negative consequences for health and the environment. The known methods of the assessment of biodegradability of lubricating oils are expensive and time-consuming. The paper proposes a principle of method and equipment for performing a quick and cheap screening test for the presence of petroleum-derived fractions containing aromatic hydrocarbons in the analyzed lubricating oil samples. The test uses an oil fluorescence test under UV light of wavelength λ = 365 nm. The proposed method is simple and does not require specialist qualifications from the user. Easy-to-prepare equipment for repetitive testing in field conditions has been described.

  • A New Rehabilitation Device for Balance Impaired Individuals
    • Wiktor Sieklicki
    • Robert Barański
    • Szymon Grocholski
    • Patrycja Matejek
    • Mateusz Dyrda
    • Konrad Klepacki
    2019

    In the paper authors present a device designed to improve the rehabilitation process of people with balance impairment. The discussed device (JStep) utilizes a commercially available static standing frame (stander) modified in order to fit force sensing units under the feet and in the pillows around the hips of a patient. While executing rehabilitation tasks, the patient may compensate his balance deficiency by leaning on the pillows around his hips. Information about weight distribution between left and right leg together with the information about the force applied to the pillows supporting the patient's body is further presented on a display in front of the patient. Such a setup allows physicians to work with the patient while having direct information about compensation necessary for completing a task or gives the patient a visual biofeedback about how well he is doing the exercise. The system is based on an ATmega controller, load cells and analogue amplifiers. In this framework a case study is presented of a 16 y.o. patient with Cerebral Palsy affecting his cerebellum, labelled as ataxic Cerebral Palsy. Two exercise scenarios utilizing the proposed device are discussed and results of a 6-week exercise are further presented. They show a decrease in necessary compensation in order to maintain a standing posture as well as a better accuracy in achieving the desired force distribution between right and left leg while standing upright.

  • A new simple approach to prepare rare-earth metals-modified TiO2 nanotube arrays photoactive under visible light: Surface properties and mechanism investigation
    • Patrycja Parnicka
    • P. Mazierski
    • Wojciech Lisowski
    • Tomasz Klimczuk
    • Joanna Nadolna
    • Adriana Zaleska-Medynska
    2019 Pełny tekst Results in Physics

    Application of Ti90RE10 alloys (RE = Ho, Er, Nd, Y, Ce, Tm) as a working electrode, instead of Ti pure foil in anodic oxidation in a fluoride-based electrolyte, resulted in formation of well-ordered nanotubes made of TiO2 and RE2O3 mixture, which could be efficiently used for pollutant removal from water and air phase upon UV and visible irradiation and easily separable from the reaction mixture to recycle. The as-prepared NTs were characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDX), diffuse reflectance spectroscopy (DRS), luminescence spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of the synthesized samples was investigated used phenol and toluene as a model compounds to follow degradation kinetics. The influence of the RE metals on the photoelectrochemical performance of modified TiO2 NTs was investigated. Surface morphology analysis showed formation of uniform and vertically oriented NTs structures with an open tube top and smooth walls. The results of EDX, XRD and XPS analysis proved that RE ions exist as surface compounds (RE3+ oxides). Visible light induced photoactivity (both photocatalytic and photoelectrochemical) is mostly pronounced in the presence of nanotubes obtained by anodic oxidation of Ti90Ho10 alloy. These nanotubes are able to degrade toluene in the gas phase even by irradiation of low-powered light source, such as light emitting diodes (λmax = 465 nm). Photocatalytic test of phenol degradation in the presence of scavenger indicates that photogenerated electrons and superoxide radicals play a meaningful role in the photocatalytic degradation of pollutants under visible irradiation. In addition, the photoelectrochemical tests performed under the influence of visible light irradiation confirmed that the RE-modification of TiO2 NTs caused a significant increase of photocurrent (up to 10 times higher). The new and original results on the preparation of RE2O3/TiO2 nanotubes obtained in one step anodic oxidation and photocatalytic activity in aqueous and gas phases represent an important contribution then will benefit photocatalytic surfaces preparation technologies.

  • A NEW TAKE ON PENITENTIARY ARCHITECTURE ARCHITEKTURA WIĘZIENNA – NOWE OBLICZE
    • Agnieszka Szuta
    2019 Pełny tekst Przestrzeń i Forma

    This article raises the issue of designing and adapting correctional facilities to the new perception of prisoners as well as comprehension of punishment. For research purposes, several European prisons which came into service over recent years were selected. A study of such facilities revealed design solutions that may significantly affect the process of rehabilitation for inmates and make such buildings an accepted part of society.

  • A Novel Approach of Using Selected Unconventional Geodesic Methods of Estimation on VTS Areas
    • Krzysztof Czaplewski
    • Mariusz Wąż
    • Marek Zienkiewicz
    2019 MARINE GEODESY

    The Vessel Traffic Service (VTS) systems belong to the fundamental tools used in ensuring a high level of safety across sea basins with heavy traffic, where the presence of navigational hazards poses a great risk of collision or a ship running aground. In order to determine the mutual location of ships, VTS systems obtain information from different facilities, such as coastal radar stations, AIS, and vision systems. Fixing a ship’s position is always accompanied by a degree of error, but the degree of error depends on the specific position fixing system used. In order to increase the accuracy of position fixing in VTS systems, the authors propose the use of contemporary geodetic methods. The article presents the theoretical fundamentals of two unconventional geodesic methods of estimation: M estimation and Msplit(q)estimation and the authors’ own proposal of their application in VTS systems. The article concludes with a test verifying theoretical assumptions, performed with the use of a computer application allowing position fixing with the use of selected robust adjustment methods. Furthermore, an example is presented of Msplit(q)estimation as used for the acquisition of low-signal radar echoes, which in VTS systems are not automatically identified for tracking. The level of the echo signal makes it difficult for a VTS controller to separate these objects from typical radar noise and interference.

  • A Novel Bitrate Adaptation Method for Heterogeneous Wireless Body Area Networks
    • Krzysztof Cwalina
    • Sławomir Ambroziak
    • Piotr Rajchowski
    • Jarosław Sadowski
    • Jacek Stefański
    2019

    In the article, a novel bitrate adaptation method for data streams allocation in heterogeneous Wireless Body Area Networks (WBANs) is presented. The efficiency of the proposed algorithm was compared with other known algorithms of data stream allocation using computer simulation. A dedicated simulator has been developed using results of measurements in the real environment. The usage of the proposed adaptive data streams allocation method by transmission rate adaptation based on radio channel parameters can increase the efficiency of resources’ usage in a heterogeneous WBANs, in relation to fixed bitrates transmissions and the use of well-known algorithms. This increase of efficiency has been shown regardless of the mobile node placement on the human body.

  • A novel heterogeneous model of concrete for numerical modelling of ground penetrating radar
    • Jacek Lachowicz
    • Magdalena Rucka
    2019 Pełny tekst CONSTRUCTION AND BUILDING MATERIALS

    The ground penetrating radar (GPR) method has increasingly been applied in the non-destructive testing of reinforced concrete structures. The most common approach to the modelling of radar waves is to consider concrete as a homogeneous material. This paper proposes a novel, heterogeneous, numerical model of concrete for exhaustive interpretation of GPR data. An algorithm for determining the substitute values of the material constants of concrete is developed, based on the modified complex refractive index method. Experimental surveys and numerical simulations are conducted on a concrete laboratory sample with a controlled degree of saturation, and on a real concrete slab with two different degrees of saturation. The results indicate that the proposed model is fully capable of realistic finite-difference time-domain modelling of concrete for ground penetrating radar diagnostics of civil engineering structures with changing water content.

  • A Novel IoT-Perceptive Human Activity Recognition (HAR) Approach Using Multi-Head Convolutional Attention
    • Haoxi Zhang
    • Zhiwen Xiao
    • Juan Wang
    • Fei Li
    • Edward Szczerbicki
    2019 Pełny tekst IEEE Internet of Things Journal

    Together with fast advancement of the Internet of Things (IoT), smart healthcare applications and systems are equipped with increasingly more wearable sensors and mobile devices. These sensors are used not only to collect data, but also, and more importantly, to assist in daily activity tracking and analyzing of their users. Various human activity recognition (HAR) approaches are used to enhance such tracking. Most of the existing HAR methods depend on exploratory case-based shallow feature learning architectures, which straggle with correct activity recognition when put into real life practice. To tackle this problem, we propose a novel approach that utilizes the convolutional neural networks (CNNs) and the attention mechanism for HAR. In the presented method, the activity recognition accuracy is improved by incorporating attention into multi-head convolutional neural networks for better feature extraction and selection. Proof of concept experiments are conducted on a publicly available dataset from Wireless Sensor Data Mining (WISDM) laboratory. The results demonstrate higher accuracy of our proposed approach in comparison with the current methods.

  • A Novel Trust-Region-Based Algorithm with Flexible Jacobian Updates for Expedited Optimization of High-Frequency Structures
    • Anna Pietrenko-Dąbrowska
    2019 Pełny tekst INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS

    Simulation-driven design closure is mandatory in the design of contemporary high-frequency components. It aims at improving the selected performance figures through adjustment of the structure’s geometry (and/or material) parameters. The computational cost of this process when employing numerical optimization is often prohibitively high, which is a strong motivation for the development of more efficient methods. This is especially important in the case of complex and multi-parameter structures. In the paper, an expedited trust-region-based algorithm for electromagnetic (EM)-driven design optimization of high-frequency structures is proposed. The presented technique involves a flexible sensitivity update scheme depending on the relative design changes with respect to the trust region size, as well as a direction of the design relocation and its alignment with the coordinate system axes. This allows for performing finite-differentiation-based sensitivity updates less frequently and, consequently, brings considerable computational savings. Numerical results obtained for an ultra-wideband antenna and a microwave coupler demonstrate that the proposed algorithm outperforms the reference procedure in terms of the number of EM simulations necessary to arrive at the optimized solution (around 50 percent). At the same time, the design quality loss is minor.

  • A numerical analysis of the thermal effects in the jet impingement stagnation zone
    • Tomasz Kura
    • Elżbieta Fornalik-Wajs
    • Jan Wajs
    • Sasa Kenjeres
    • Sebastian Gurgul
    2019

    Most of the flows occurring in the engineering systems are turbulent and their accurate numerical analysis is still challenging, especially when combined with the heat transfer. One of the methods of heat transfer enhancement is utilization of the turbulent impinging jets, which were recently applied also in the heat exchangers. Their positive impact on the heat transfer performance was proven, but many questions related to its origin are still unanswered. In general, the wall-jet interaction and the near-wall turbulence are supposed to be its main reason. The authors are interested in construction of the numerical model assuring the results as close as possible to the experimental one and then modelling the transport processes in the heat exchanger. The most difficult area to model is the stagnation region, where the thermal effects are strongly affected by the conditions in the pipe/nozzle/orifice, from which the jet is originated. In the following article, summary of authors’ findings, regarding significance of the velocity profile or turbulence intensity at the inlet, are presented. In addition, qualitative analysis of the heat transfer enhancement is included, in relation to the inlet conditions.

  • A Reduction Method for Bathymetric Datasets that Preserves True Coastal Water Geodata
    • Marta Wlodarczyk-Sielicka
    • Andrzej Stateczny
    • Jacek Lubczonek
    2019 Pełny tekst Remote Sensing

    Water areas occupy over 70 percent of the Earth’s surface and are constantly subject to research and analysis. Often, hydrographic remote sensors are used for such research, which allow for the collection of information on the shape of the water area bottom and the objects located on it. Information about the quality and reliability of the depth data is important, especially during coastal modelling. In-shore areas are liable to continuous transformations and they must be monitored and analyzed. Presently, bathymetric geodata are usually collected via modern hydrographic systems and comprise very large data point sequences that must then be connected using long and laborious processing sequences including reduction. As existing bathymetric data reduction methods utilize interpolated values, there is a clear requirement to search for new solutions. Considering the accuracy of bathymetric maps, a new method is presented here that allows real geodata to be maintained, specifically position and depth. This study presents a description of a developed method for reducing geodata while maintaining true survey values.

  • A SEARCH OF AN INDUCER GEOMETRY THAT IS BENEFICIAL FOR LIFTING PARAMETERS OF A LIFTED OBJECT OF A SELECTED SHAPE
    • Bartosz Bastian
    • Rafał Gawarkiewicz
    2019 Pełny tekst TRIBOLOGIA

    The literature describes acoustic levitation phenomena with the utilization of air squeeze film between the vibrating inducer and the lifted object. The objective of the study is to determine the shape of the inducer with vibration characteristics that would allow the levitation of an object of the assumed geometry. In this paper, the influence of the dimension ratio of the inducer on the frequency of the first mode of vibration was presented. CFD calculations for a selected dimension series were performed with the goal of the determination of lifting conditions. The data obtained from the analysis will be used to manufacture an inducer that will serve as an experimental verification for the fluid dynamics calculation.

  • A semi-empirical model for flow boiling heat transfer with account of the reduced pressure effect
    • Blanka Jakubowska
    • Stanisław Głuch
    • Jan Wajs
    • Dariusz Mikielewicz
    2019

    In the present study the attention was focused on the influence of reduced pressure on the predictions of heat transfer during flow boiling at the extensive range of pressures. The results of calculations were to test the sensitivity of the in-house flow boiling model with respect to the selection of the appropriate two-phase flow multiplier, which is one of the distinctive elements of that model. For this purpose a few two-phase frictional pressure drop correlations were tested. The purpose of this paper is to show that taking into account the effect of the reduced pressure in a model can be of significant importance on the predictions of heat transfer during flow boiling. In the paper are presented the results of calculations using the authors' own model to predict heat transfer coefficient during flow boiling. The model has been tested against a large selection of experimental data collected from various researchers to investigate the sensitivity of the in-house developed model. In the work are presented the results of calculations obtained using the in-house developed semi empirical model on selected experimental flow boiling data of the following refrigerants: R134a, R1234yf, R600a and CO2.

  • A Set of Experience-Based Smart Synergy Security Mechanism in Internet of Vehicles
    • Fei Li
    • Haoxi Zhang
    • Lulu Gao
    • Juan Wang
    • Cesar Sanin
    • Edward Szczerbicki
    2019 CYBERNETICS AND SYSTEMS

    In this article, we introduce a novel security mechanism, the Smart Synergy Security (3S). The mechanism uses the Set of Experience Knowledge Structure (SOEKS) and the synergy of security methods in different domains to provide the global optimal security strategy. The proposed strategy is taking into account the characteristics of information security (i.e. confidentiality, integrity, availability, controllability, and reviewability) imposed in different domains in Internet of Vehicles (IoV). The SOEKS is used to represent knowledge, and is combined with the data flow in each domain. Initial experiments demonstrate that the proposed approach is able to find the optimal solution under different conditions for multi-domain security problems in IoV.

  • A Simple-Topology Compact Broadband Circularly Polarized Antenna With Unidirectional Radiation Pattern
    • Ubaid Ullah
    • Sławomir Kozieł
    • Ismail Mabrouk
    2019 Pełny tekst IEEE Antennas and Wireless Propagation Letters

    In this letter, a geometrically simple, reflector-backed single-point-fed circularly polarized (CP) antenna with unidirectional radiation pattern is presented. The structure comprises a simple coplanar waveguide (CPW) feeding circuit with an open slot etched on one side of the coplanar ground. The enhanced CP bandwidth is obtained by combining the loop mode, the slot mode, and the asymmetrical configuration of the coplanar ground planes along the feed line. All parameters are optimized at the full-wave level of description for the best impedance and axial ratio (AR) bandwidth. The antenna footprint is only 0.35 λo×0.39 λo at the lowest CP operating frequency of 3.1 GHz. The measurement results indicate 82% impedance bandwidth (from 3 GHz to 7.2 GHz), and 80% AR bandwidth (from 3.1 GHz to 7.2 GHz). A unidirectional right-hand circular polarization (RHCP) radiation pattern in the +z-direction is also achieved by adding a reflector. The peak realized gain of the antenna is 6.7 dBic, and the peak radiation efficiency is 98%.

  • A Simplified Method of Trend Removal to Determine Noise Observed During a Supercapacitor’s Discharging
    • Łukasz Lentka
    • Janusz Smulko
    2019 Pełny tekst FLUCTUATION AND NOISE LETTERS

    In this paper, new method of trend removal is proposed. This is a simplified method based on Empirical Mode Decomposition (EMD). The method was applied for voltage time series observed during supercapacitor discharging process. It assured the determination of an additive noise component after subtracting the identified trend component. We analyzed voltage time series observed between the terminals of the supercapacitor when discharged by a loading resistance R. The steps of the proposed method are presented in detail. The results are compared with the results obtained for polynomial approximation. Statistical parameters (kurtosis, skewness) of the histograms of the identified noise component were estimated to evaluate the quality of the proposed detrending method. The method was adjusted to the analyzed data by selecting a parameter of the applied envelope function of the EMD method. We conclude that the proposed method is faster and more efficient for detecting the additive noise component than the competitive polynomial approximation. The identified noise component may be used to evaluate the State of Health of tested supercapacitors and therefore requires fast algorithms with efficient detection.

  • A study of a compact high-efficiency zero-emission power plant with oxy-fuel combustion
    • Paweł Ziółkowski
    • Janusz Badur
    2019

    This paper discusses the application of global trends in gas cycles technology using oxy-fuel combustion. This is followed by a demonstration of a design solution for a new cycle with two enhanced energy-converting devices, namely a wet combustion chamber and a spray-ejector condenser. The proposed gas and steam cycle unit is contained within a single turbine, whose benefits combine those offered by gas turbines (high inlet temperatures) and steam turbines (full expansion into a vacuum). The efficiency of the oxy-fuel combustion system with carbon dioxide capture was determined based on thermodynamic analyses carried out using in-house codes (COM-GAS). The motivation behind this research paper was provided by calls for diversification in the power generation industry in Poland as well as the need for new solutions in power plants, including compact ones. Compactness can be achieved when the plant is rid of its largest components such as the heat recovery steam generator and the conventional steam condenser. For this, it would be necessary to design non-standard cutting-edge devices, but the counterbalancing pay-off would be in their size, reduced to the point where power plants, in which they are installed, will be able to adequately address the needs of urban users and cater for heat production demand. The concept under consideration is based on the use of shale gas deposits in the place of extraction in a compact, zero-emission gas-steam turbine power system. In our case power plant compactness is achieved by using two new devices, namely: 1) a wet combustion chamber (with oxy-combustion and combustion chamber walls cooling by thermal transpiration); 2) a condenser spray-ejector (using a bulk condensation of vapor-gas). The main aim of the spray-ejector condenser is simultaneously condensing steam and compressing CO2 from the condensation pressure to about 1 bar. Hence, the most important innovation of this steam-gas cycle emerges as the enhanced condensation, which is based on the nano-injection of cold water and a jet-powered compression of CO2 performed in the spray-ejector condenser.

  • A Study of Transport Behaviour of Academic Communities
    • Aleksandra Romanowska
    • Romanika Okraszewska
    • Kazimierz Jamroz
    2019 Pełny tekst Sustainability

    An important challenge to achieving sustainable university campuses is ensuring that the academic community makes sustainable transport choices. The objective of this study was to investigate the daily commuting patterns, identify the potential for change, and determine the factors and criteria affecting the transport decisions of academic communities of two universities located in Gdansk, Poland. This paper summarizes the results of trip generation measurements and a comprehensive online survey of 3678 respondents, including the universities’ staff and students. Analysis of survey results revealed clear differences between students and university staff in terms of travel patterns and factors that influence their choices. Staff usually (57%) choose the car for daily commutes with students opting for public transport (59%). The choice of travel mode in particular groups is determined mostly by car availability, trip origin location, and accessibility. The choices also depend on transport user individual requirements such as trip quality, costs, or ecology. With approximately 1400 trips daily per 1000 students, the universities are large traffic generators. Thus, how the staff and students behave determines the effect the universities have on the urban transport system. Understanding the behaviour can help to estimate whether it can be changed and how.