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Composition Patterns of Contemporary Polish Residential Building Facades
PublicationThis study aims to define the types of composition patterns of contemporary Polish multi-family building facades. The authors define the compositional patterns to determine their frequency. Analyses carried out on the basis of photos and visualizations of 113 examples of architecture from Poland identified groups of common features of facades. Statistical analyses of these features resulted in six types of compositions. Clear differences...
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Measurements of Dispersed Phase Velocity in Two-Phase Flows in Pipelines Using Gamma-Absorption Technique and Phase of the Cross-Spectral Density Function
PublicationThis paper concerns the application of the gamma radiation absorption method in the measurements of dispersed phase velocity in two-phase flows: liquid–gas flow in a horizontal pipe- line and liquid–solid particles in a vertical pipe. Radiometric sets containing two linear 241Am gamma radiation sources and two NaI(Tl) scintillation detectors were used in the research. Due to the stochastic nature of the signals obtained from the...
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Accuracy assessment of mobile satellite measurements in relation to the geometrical layout of rail tracks
PublicationThe paper presents the campaigns of mobile satellite measurements, carried out in 2009–2015 on the railway and tram lines. The accuracy of the measurement method has been analysed on the basis of the results obtained in both horizontal and vertical planes. The track axis deviation from the defined geometric shape has been analysed in the areas clearly defined in terms of geometry, i.e. on the straight sections and sections with...
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Role of nitrogen in evolution of sp2/sp3 bonding and optical band gap in hydrogenated carbon nitride
PublicationDrastic changes in the bonding are found in amorphous hydrogenated carbon nitride (a-CNx:H) film as a function of nitrogen concentration (or N/C ratio). The total C-sp3 fraction and hardness shows a sharp decrease (at N/C = 0.40) whereas optical band gap and resistivity shows a gradual increase as nitrogen concentration increases from 0.07 to 0.58. Raman spectrum of a-CNx:H film is fitted with both Gaussian (integrated intensity...
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Graph security testing
PublicationSet S ⊂ V is called secure set iff ∀ X ⊂ S | N [ X ] ∩ S | ≥ | N ( X ) \ S | [3]. That means that every subset of a secure set has at least as many friends (neighbour vertices in S) as enemies (neighbour vertices outside S) and will be defended in case of attack. Problem of determining if given set is secure is co −NP -complete, there is no efficient algorithm solving it [3]. Property testers are algorithms that distinguish inputs...
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Eqiuitable coloring of corona products of cubic graphs is harder than ordinary coloring
PublicationA graph is equitably k-colorable if its vertices can be partitioned into k independent sets in such a way that the number of vertices in any two sets differ by at most one. The smallest k for which such a coloring exists is known as the equitable chromatic number of G. In this paper the problem of determinig the equitable coloring number for coronas of cubic graphs is studied. Although the problem of ordinary coloring of coronas...
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Rigid polyurethane foams with different flame retardants and their physical and mechanical properties
PublicationRigid polyurethane foams (PUFs) containing 3, 6 or 9 % of one of of two selected fire retardants (FR): oligomeric ethyl ethylene phosphate (Fyrol PNX) and expandable graphite (EG) were prepared, inspected and compared to foam without that fillers as the control. The thermal stability of PUFs was described by horizontal test according to norm: UL 94 HB. Compressive strength and physical properties (density, fragility and water absorption)...
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Circularly Polarized Antenna Array design with the Potential of Gain-Size Trade-off and Omnidirectional Radiation for Millimeter-Wave Small Base Station Applications
PublicationThis paper presents the design and validation of a slot-patch-hybrid circularly polarized antenna array for 28 GHz millimeter (mm) wave (mm-wave) applications. The proposed design has a simple geometry that facilitates the fabrication process, which is otherwise a challenging task due to the sub-mm dimensions of the circuit in the mm-wave band. In the proposed structure, aperture-coupled series slot-fed array is utilized to excite...
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Estimation of groundwater recharge in a shallow sandy aquifer using unsaturated zone modeling and water table fluctuation method
PublicationQuantification of groundwater recharge is one of the most important issues in hydrogeology, especially in view of the ongoing changes in climate and land use. In this study, we use numerical models of 1D vertical flow in the vadose zone and the water table fluctuation (WTF) analysis to investigate local-scale recharge of a shallow sandy aquifer in the Brda outwash plain in northern Poland. We show that these two methods can be...
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A magnetic imprinted polymer nano-adsorbent with embedded quantum dots and mesoporous carbon for the microextraction of triazine herbicides
PublicationA magnetic molecularly imprinted polymer (MMIP) adsorbent incorporating amino-functionalized magnetite nanoparticles, nitrogen-doped graphene quantum dots and mesoporous carbon (MIP@MPC@NGQDs@ Fe3O4–NH2) was fabricated to extract triazine herbicides from fruit juice. The embedded magnetite nanoparticles simplified the isolation of the adsorbent from the sample solution. The N-GQDs and MPC enhanced adsorption by affinity binding...
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Global Complex Roots and Poles Finding Algorithm in C × R Domain
PublicationAn algorithm to find the roots and poles of a complex function depending on two arguments (one complex and one real) is proposed. Such problems are common in many fields of science for instance in electromagnetism, acoustics, stability analyses, spectroscopy, optics, and elementary particle physics. The proposed technique belongs to the class of global algorithms, gives a full picture of solutions in a fixed region ⊂ C × R and...
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Bezzałogowe środki latające (BSL) w układzie czterowirnikowego helikoptera
PublicationRozwój układów sterowania, kamer pracujących w świetle widzialnym oraz w podczerwieni doprowadził do wzrostu znaczenia bezpilotowych środków latających. Bezpilotowe środki latające wykorzystywane są do realizacji celów zarówno wojskowych, jak i cywilnych. Podstawowymi zaletami bezpilotowych środków latających są: małe wymiary, duża mobilność, niskie koszty wytworzenia i eksploatacji. Użytkowanie bezpilotowych środków latających...
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Noise and Electro-Ultrasonic Spectroscopy of Conducting PolymerThick Films
PublicationThick conducting films based on conducting polymer are characterized by DC conductivity and noise in temperature range 10 to 300 K. Conducting polymers could be used e.g. for the top electrode (cathode) in the solid tantalum or niobium capacitors. On the conducting polymer layer the top layer of carbon/graphite and/or silver polymer based pastes is applied in the capacitor technology. Our samples structure consists of conducting...
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Valence and lowest Rydberg electronic states of phenol investigated by synchrotron radiation and theoretical methods
PublicationWe present the experimental high-resolution vacuum ultraviolet (VUV) photoabsorption spectra of phenol covering for the first time the full 4.3–10.8 eV energy-range, with absolute cross sections determined. Theoretical calculations on the vertical excitation energies and oscillator strengths were performed using time-dependent density functional theory and the equation-of-motion coupled cluster method restricted to single and double...
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Removal and speciation of heavy metals in the constructed wetland treating landfill leachate
PublicationThe results of heavy metals removal and speciation of metals at two treatment wetlands receiving landfill are discussed. The first TW is a surface flow facility consisting of 10 ponds. The next TW is a newly constructed pilot-scale facility consisting of three beds with alternately vertical and horizontal sub-surface flow. The metals concentrations were analysed in leachate(both TWs) and bottom sediments (surface flow TW). Seasonal...
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Superexcited states in the vacuum-ultraviolet photofragmentation of isoxazole molecules
PublicationThe photofragmentation of isoxazole molecules producing excited atomic and molecular fragments has been investigated over the energy range 16-50 eV, using photon-induced fluorescence spectroscopy. The following fragments have been identified by their fluorescence: the excited hydrogen atoms H(n), n = 3-7 and the diatomic CH(A2Δ, B2Σ−), CN(B2Σ+) and C2(d3Πg) fragments. The diatomic fragments are vibrationally and highly rotationally...
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The analysis of the determination of points positions using photogrammetric methods
PublicationThis article was created as a result of research conducted within the master thesis. The purpose of the research was to analyze the accuracy of determining the actual position of the photographed points according to the calculated parameters. The accuracy of photos alignment was determined as parameters, which determine their external and internal orientation. In order to determine the location of the determined points, it was...
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Concept of a swirling diffuser in batch blending tanks
PublicationThe mixing of two or more components belongs to the category of the most common unit operations, both in technology and in nature. One particular version is homogenization (blending), the effectivity of which is strongly related to the blending time. Among many differentiated individual solutions of mixing systems used in blenders, one should distinguish the class of agitators with diffusers. An analysis of the character of the...
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Centrifuge modelling of tapered wall jacked into dense sand
PublicationA series of static penetration tests of trapezoidal walls in dense Fontainebleau sand were performed in the geotechnical centrifuge at Gustave Eiffel University. The models of wall with three different shapes (straight profile with thickness D=16mm, 0.75 degree and 1.5 degree of taper angle) but with the same volume were used. The soil mass was instrumented with five stress cells located at two levels at 2D, 4D and 6D distance...
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Valence and ionic lowest-lying electronic states of ethyl formate as studied by high-resolution vacuum ultraviolet photoabsorption, He(I) photoelectron spectroscopy, and ab initio calculations
PublicationThe highest resolution vacuum ultraviolet photoabsorption spectrum of ethyl formate, C2H5OCHO, yet reported is presented over the wavelength range 115.0–275.5 nm (10.75–4.5 eV) revealing several new spectral features. Valence and Rydberg transitions and their associated vibronic series, observed in the photoabsorption spectrum, have been assigned in accordance with new ab initio calculations of the vertical excitation energies...
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Buckling Analysis of Cold Formed Silo Column
PublicationThe paper is devoted to stability analysis of different models of steel cold formed silo column. The steel cylindrical silos are often composed of corrugated walls and vertical open-sectional columns uniformly placed along the silo circumference. Both the whole 3D silo, a simplified model consisting of one column with a part of the silo walls, and a single column resting on elastic foundation provided by the silo walls were analyzed....
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Effectiveness of pollutants removal in hybrid constructed wetlands – different configurations case study
PublicationIn recent years, an increase in interest in hybrid constructed wetland systems (HCWs) has been observed. The aim of the paper is to compare different HCW configurations in terms of mass removal rates and efficiency of pollutants removal. Analysed data have been collected at multistage constructed wetlands in Poland, which are composed by at least two beds: horizontal subsurface flow (SSHF) and vertical subsurface flow (SSVF). The...
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Correlation between natural frequencies and buckling load in a stiffened shell
PublicationThe paper deals with correlation between natural frequencies and buckling load of a stiffened shell composed of corrugated sheets and vertical stiffeners (columns). The simplified shell segment represents the buckling behaviour of a whole silo with sparsely distributed columns. The paper covers variants of linear buckling anal-yses, dynamic eigenvalue analyses and geometrically non-linear analyses of a segment modelled with shell...
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Footbridges. Dynamic Design – Selected Problems
PublicationModern footbridges create challenge in esthetic and structural design. Breaking the proven canons is a recipe for architectural success. However esthetic form has to be also a functional pedestrian bridge. Therefore a good FEM modeling is a key element in engineering part of design. The paper presents selected problems related to the modeling of the dynamic construction of footbridges. Several basic dynamic problems concerning...
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The Effect of Flexible Pavement Mechanics on the Accuracy of Axle Load Sensors in Vehicle Weigh-in-Motion Systems
PublicationWeigh-in-Motion systems are tools to prevent road pavements from the adverse phenomena of vehicle overloading. However, the effectiveness of these systems can be significantly increased by improving weighing accuracy, which is now insufficient for direct enforcement of overloaded vehicles. Field tests show that the accuracy of Weigh-in-Motion axle load sensors installed in the flexible (asphalt) pavements depends on pavement temperature...
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A model of the response of the MGS-6 gravity sensor to tilting
PublicationThe reliable interpretation of the measurements made by the Micro-g marine gravimetric system (MGS-6) depends on how the temporary changes of the scale coefficients such as gravimeter scale factor, vertical cross-coupling (VCC) effect, tiltmeter cross and tiltmeter long are compensated for during the signal analysis. The listed coefficients cannot be determined from readings during the measurements or by analysing the final data....
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Comparative tests of the wall thickness effect of a glass-reinforced thermosetting plastic coating with a non-circular cross section in a soil-coating object for economic aspect
PublicationCulvert structures made of plastics are employed extensively in the construction of new facilities as well as the renovation of existing ones. Due to the high costs of materials required for the manufacturing of these goods, the objective of this research is focused to lessen the thickness of the walls, which may, on the other hand, result in a reduction in the stiffness of the system. In the course of the testing, the structure...
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A comprehensive approach to SBR modelling for monitoring and control system design
PublicationThe aim of this research is to provide a comprehensive description of the Sequencing Batch Reactor (SBR) modelling for monitoring, control, and plant operational optimisation validation. The paper provides a detailed modelling of the SBR, its components and constituent processes. For this purpose, the mass balance principle and continuity equations were provided with a reactive term implemented using Activated Sludge Model (ASM)....
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Minimum order of graphs with given coloring parameters
PublicationA complete k-coloring of a graph G=(V,E) is an assignment F: V -> {1,...,k} of colors to the vertices such that no two vertices of the same color are adjacent, and the union of any two color classes contains at least one edge. Three extensively investigated graph invariants related to complete colorings are the minimum and maximum number of colors in a complete coloring (chromatic number χ(G) and achromatic number ψ(G), respectively),...
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Network Approach to Increments of RR-intervals for Visualization of Dynamics of Cardiac Regulation
PublicationThe transition network for RR -increments is pre- sented in a directed and weighted graph, with vertices represent- ing RR -increments and edges corresponding to the order in a sequence of increments. The adjacency matrix and the transition matrix of this network provide a graphical tool which could be useful in the assessment of cardiac regulation. As an example, the method is applied in detecting differences between diurnal activity...
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Sharp bounds for the complexity of semi-equitable coloring of cubic and subcubic graphs
PublicationIn this paper we consider the complexity of semi-equitable k-coloring of the vertices of a cubic or subcubic graph. We show that, given n-vertex subcubic graph G, a semi-equitable k-coloring of G is NP-hard if s >= 7n/20 and polynomially solvable if s <= 7n/21, where s is the size of maximum color class of the coloring.
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Balance recognition on the basis of EEG measurement.
PublicationAlthough electroencephalography (EEG) is not typically used for verifying the sense of balance, it can be used for analysing cortical signals responsible for this phenomenon. Simple balance tasks can be proposed as a good indicator of whether the sense of balance is acting more or less actively. This article presents preliminary results for the potential of using EEG to balance sensing....
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N-doped mesoporous carbon nanosheets obtained by pyrolysis of a chitosan–melamine mixture for the oxygen reduction reaction in alkaline media.
PublicationBy simple thermal decomposition of low-cost precursors (chitosan, melamine) in an inert atmosphere, nitrogen-doped porous carbonaceous materials were prepared. The samples pyrolyzed at 700 C are composed of mainly mesoporous nitrogen-doped carbon nanosheets and partially graphitized carbon. The nanosheets contain a disordered area due to the strain imposed by the presence of nitrogen and/or oxygen groups in their structure. Some...
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Applying molecular dynamics simulation to take the fracture fingerprint of polycrystalline SiC nanosheets
PublicationGraphene-like nanosheets are the key elements of advanced materials and systems. The mechanical behavior of the structurally perfect 2D nanostructures is well documented, but that of polycrystalline ones is less understood. Herein, we applied molecular dynamics simulation (MDS) to take the fracture fingerprint of polycrystalline SiC nanosheets (PSiCNS), where monocrystalline SiC nanosheets (MSiCNS) was the reference nanosheet....
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The Backbone Coloring Problem for Small Graphs
PublicationIn this paper we investigate the values of the backbone chromatic number, derived from a mathematical model for the problem of minimization of bandwidth in radio networks, for small connected graphs and connected backbones (up to 7 vertices). We study the relationship of this parameter with the structure of the graph and compare the results with the solutions obtained using the classical graph coloring algorithms (LF, IS), modified...
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Equitable and semi-equitable coloring of cubic graphs and its application in batch scheduling
PublicationIn the paper we consider the problems of equitable and semi-equitable coloring of vertices of cubic graphs. We show that in contrast to the equitable coloring, which is easy, the problem of semi-equitable coloring is NP- complete within a broad spectrum of graph parameters. This affects the complexity of batch scheduling of unit-length jobs with cubic incompatibility graph on three uniform processors to minimize...
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Double bondage in graphs
PublicationA vertex of a graph is said to dominate itself and all of its neighbors. A double dominating set of a graph G=(V,E) is a set D of vertices of G such that every vertex of G is dominated by at least two vertices of D. The double domination number of a graph G, denoted by gamma_d(G), is the minimum cardinality of a double dominating set of G. The double bondage number of G, denoted by b_d(G), is the minimum cardinality among all sets...
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On the size of identifying codes in triangle-free graphs
PublicationIn an undirected graph G, a subset C⊆V(G) such that C is a dominating set of G, and each vertex in V(G) is dominated by a distinct subset of vertices from C, is called an identifying code of G. The concept of identifying codes was introduced by Karpovsky, Chakrabarty and Levitin in 1998. For a given identifiable graph G, let gammaID(G) be the minimum cardinality of an identifying code in G. In this paper, we show that for any connected...
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Rigid polyurethane foams modified with selected flame retardants
PublicationThe flame retardants: expandable graphite, triethylphosphatehas been used in rigid polyurethane foams (PUFs). The influence of fillers amounts on processing parameters, physical-mechanical properties (compression strength, density, water absorption, brittleness)and thermal properties (thermal stability) of such foams has been analyzed.The gel, cram and rise time for PUFs modified with flame retardant has been observed during synthesis...
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Cavitation Erosion of Nodular Cast Iron - Microstructural Effects
PublicationThe paper deals with susceptibility of nodular cast iron with ferritic-pearlitic matrix on cavitation erosion. Cavitation tests were carried out with the use of a cavitation erosion vibratory apparatus employing a vibration exciter operated at frequency of 20 kHz. The study allowed to determine the sequence of subsequent stages in which microstructure of cast iron in superficial regions is subject to degradation. The first features...
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Tight bounds on the complexity of semi-equitable coloring of cubic and subcubic graphs
PublicationWe consider the complexity of semi-equitable k-coloring, k>3, of the vertices of a cubic or subcubic graph G. In particular, we show that, given a n-vertex subcubic graph G, it is NP-complete to obtain a semi-equitable k-coloring of G whose non-equitable color class is of size s if s>n/3, and it is polynomially solvable if s, n/3.
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A space-efficient algorithm for computing the minimum cycle mean in a directed graph
PublicationAn algorithm is introduced for computing the minimum cycle mean in a strongly connected directed graph with n vertices and m arcs that requires O(n) working space. This is a considerable improvement for sparse graphs in comparison to the classical algorithms that require O(n^2) working space. The time complexity of the algorithm is still O(nm). An implementation in C++ is made publicly available at http://www.pawelpilarczyk.com/cymealg/.
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Total chromatic sum for trees
PublicationThe total chromatic sum of a graph is the minimum sum of colors (natural numbers) taken over all proper colorings of vertices and edges of a graph. We provide infinite families of trees for which the minimum number of colors to achieve the total chromatic sum is equal to the total chromatic number. We construct infinite families of trees for which these numbers are not equal, disproving the conjecture from 2012.
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Friction and Lubrication of Large Tilting-Pad Thrust Bearings
PublicationFluid film bearings have been extensively used in the industry because of their unbeatable durability and extremely low friction coefficient, despite a very low coefficient of friction dissipation of energy being noticeable, especially in large bearings. Lubricating systems of large tilting pad thrust bearings utilized in large, vertical shaft hydrogenerators are presented in this paper. A large amount of heat is generated due...
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Rural domestic wastewater treatment in Norway and Poland: experiences, cooperation and concepts on the improvement of constructed wetland technology
PublicationThis article describes Norwegian and Polish experiences concerning domestic wastewatertreatment obtained during nearly 20 years of operation for constructed wetland (CW) systemsin rural areas and scattered settlements. The Norwegian CW systems revealed a highperformance with respect to the removal of organic matter, biogenic elements and faecalindicator bacteria. The performance of the Polish CW systems was unstable, and varied...
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STABILITY ANALYSIS OF A TRUSS WITH SLOPING ELASTIC BRACES
PublicationSteel trusses have a much greater strength and stiffness in their plane than out of their plane, and therefore should be braced against lateral deflection and twisting. Such elements like purlins apart from bearing vertical load are part of bracing that stabilize roof trusses against distortional buckling. The stability of trusses with elastic bracing was investigated in an experimental research. Braces situated at some angle measured...
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Spatial characterization of H 2: CH 4 dissociation level in microwave ECR plasma source by fibre-optic OES
PublicationSpatially resolved optical emission spectroscopy (SR-OES) was used to investigate microwave activated H2/Ar/CH4 plasma under conditions of the electron cyclotron resonance (ECR). The chemistry and composition of the gas phase were studied using self-designed fibre-optic system with echelle type spectrometer during CVD deposition of polycrystalline diamond. One-dimensional intensity profiles of the main species were collected along...
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Degradation of stiffness of building columns exposed to bending and impact load during ground motions
PublicationThe safety of civil engineering structures under external loads, including ground motions, is one of the issues related to the idea of sustainable society. The earthquake-induced soft-storey failure is a typical type of damage observed in buildings due to seismic excitation. The failure of an intermediate soft storey of a structure results in large vertical impact loading acting on the lower floors due to the fall of the upper...
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Numerical Analysis of a Steel Frame Building with Soft-storey Failure under Ground Motion Excitation
PublicationThe aim of this paper is to show the results of a numerical analysis focused on the behaviour of multi-storey steel frame building that suffers from a soft-storey failure under ground motion excitation. A numerical model of the structure was created in FEM computer software and was exposed to an impact that would have been generated after a soft-storey failure due to falling of the upper floors. During the analysis, the whole structure...
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Potential and limits of landfill leachate treatment in a multi-stage subsurface flow constructed wetland – evaluation of organics and nitrogen removal
PublicationConstructed wetlands have potential of treating wastewater of poor biodegradability. The performance of a multistage sub-surface flow wetland treating municipal landfill leachate was assessed during three years of operation. During the study three research periods with different operation conditions were established. The hydralic loads, operation mode of vertical flow beds and type of treated wastewater (raw leachate – leachate...