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Gdańsk University of Technology

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  • No Evidence for Sex-specificity in Vitamin C, E and Fatty Acid Content of Human Milk from Healthy Polish Mothers
    • Maciej Zagierski
    • Anna Krukowska
    • Karolina Kawska
    • Dorota Martysiak-Żurowska
    • Katarzyna Sznurkowska
    • Agnieszka Szlagatys-Sidorkiewicz
    2021 Full text JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION

    Human milk (HM) is a complex fluid that meets the nutritional needs of infants. Its composition idrfs associated with environmental, maternal, and foetal variables. It provides nutrients and bioactive substances, including cytokines, immunoglobulins, and constituents with antioxidative properties. Boys are reportedly more susceptible to oxidative stress. This study aimed to determine the relationship between infant sex and the antioxidants vitamins C and E, and the fatty acid (FA) profile of HM. Results of this investigation may infer sex differences for the composition of infant formulas. Thirty days after delivery, a sample of HM was collected from 152 healthy, non-smoking mothers of full-term new-borns (77 males) born in good clinical condition. After FAs were extracted from the fat component, they were converted into methyl esters and separated using high-performance gas chromatography. Tocopherol content was determined using a method described in a previous study. Vitamin C content was determined using reversed-phase high-performance liquid chromatography with ultraviolet detection, as described in the same study. The study groups (male versus female offspring) did not differ in terms of vitamin and FA content in HM. The only difference found was in gondoic acid 20:1 (n-9), with a higher concentration in the HM of mothers with female offspring (mean 0.63 ± 0.18 versus 0.59 ± 0.15 g/100 g FA; p < 0.047). Despite the acknowledged differences in the composition of HM associated with infant sex and the increased oxidative stress in males, antioxidant content did not appear to differ according to infant sex. These results suggest that there is no need for the antioxidant content of infant formulas to be sex specific.

  • Nomination Dossier, The Modernist Centre of Gdynia, Part 2b, History and Development
    • Maria Sołtysik
    2021

    History and development of Gdynia, from Medieval times up until today. The project concerns such chapters as: Introduction; The village of Gdynia; Gdynia as a seaside resort; Construction of the port and the city in the interwar period; The modernist city centre – layout; architecture;Architecture of the city centre; South Pier and Grand District; Post-war development of Śródmieście: a continuation

  • NOMINATION DOSSIER, The Modernist Centre of Gdynia, parts 4 - 7
    • Robert Hirsch
    • Celina Łozowska
    • Anna Orchowska-Smolińska
    • Katarzyna Piotrowska
    • Maria Sołtysik
    2021

    The city of Gdynia is commonly known in Poland as a symbol of the country’s independence and evidence of the foresight of planners and politicians. It is the outcome of the efforts and aspirations of generations of people from all kinds of backgrounds who made Gdynia their home. Document prepared by researchers from Gdansk University of Technology and other experts is the important part of the Nomination Dossier prepared for international official bodies (ICOMOS, UNESCO) to present the city, its assets and current state of protection.

  • Non-Coaxially Rotating Motion in Casson Martial along with Temperature and Concentration Gradients via First-Order Chemical Reaction
    • Noman Jabbar
    • Muhammad Bilal Hafeez
    • Sameh Askar
    • Umar Nazir
    2021 Full text ENERGIES

    The effect of non-coaxial rotation on the transport of mass subjected to first-order chemical reaction is studied analytically. The effects of thermal radiation, buoyancy, constructive and destructive chemical reactions along with Casson fluid in rotating frame are discussed. Time evolution of primary and secondary velocities, energy and solute particles are analyzed. The behavior of flow under the variation of intensity of magnetic field is also investigated. Evolutionary behavior of primary velocity is opposite to the evolutionary behavior of secondary velocity. The impact of buoyant force on primary velocity is opposite to the role of buoyant force on the secondary velocity. The evolutionary behavior of temperature is also examined and a remarkable enhancement in temperature is noticed. Thermal radiation causes the fluid to be cooled down as heat energy is escaped by thermal radiation. Evolutionary behavior of concentration is also analyzed and an increasing of concentration versus time is noted. Destructive chemical reaction results a remarkable reduction in the concentration and vice versa for generative chemical reaction.

  • Non-Destructive Diagnostics of Concrete Beams Strengthened with Steel Plates Using Modal Analysis and Wavelet Transform
    • Magdalena Knak
    • Erwin Wojtczak
    • Magdalena Rucka
    2021 Full text Materials

    Externally bonded reinforcements are commonly and widely used in civil engineering objects made of concrete to increase the structure load capacity or to minimize the negative effects of long-term operation and possible defects. The quality of adhesive bonding between a strengthened structure and steel or composite elements is essential for effective reinforcement; therefore, there is a need for non-destructive diagnostics of adhesive joints. The aim of this paper is the detection of debonding defects in adhesive joints between concrete beams and steel plates using the modal analysis approach. The inspection was based on modal shapes and their further processing with the use of continuous wavelet transform (CWT) for precise debonding localization and imaging. The influence of the number of wavelet vanishing moments and the mode shape interpolation on damage imaging maps was studied. The results showed that the integrated modal analysis and wavelet transform could be successfully applied to determine the exact shape and position of the debonding in the adhesive joints of composite beams.

  • Nondestructive methods complemented by FEM calculations in diagnostics of cracks in bridge approach pavement
    • Mikołaj Miśkiewicz
    • Karol Daszkiewicz
    • Jacek Lachowicz
    • Paweł Tysiąc
    • Piotr Jaskuła
    • Krzysztof Wilde
    2021 AUTOMATION IN CONSTRUCTION

    Nondestructive methods of road pavement diagnostics are an alternative to traditional approach to pavement failure investigation. The article presents a detailed multidisciplinary inspection carried out using ground-penetrating radar (GPR), laser scanning technology and finite element method (FEM) calculations. It was done in order to assess the factors that contributed to occurrence of premature cracks of a bridge approach pavement. Assessments of permittivity values in the GPR method are dependent on two factors: thickness of successive layers and electromagnetic wave reflection in time. Electromagnetic field propagation in the pavement structure was also simulated using two numerical models: the first one reflected the undamaged pavement, while the second one included the defects next to the bridge joint. The comparison of the radargrams for both models enables identification of reflections and anomalies caused by the assumed defects. Nonhomogeneous compaction zones in the bridge approach pavement structure were detected by analysis of layer permittivity and anomalies observed in the in situ GPR maps. The GPR measurements were positively verified afterwards by values of air void content in the pavement layers, determined in standard invasive tests. Laser scanning technology was also used in the distressed area in order to assess its geometric changes. Results are presented in the form of contour plots depicting differences between the measured and the designed surfaces. The three-dimensional finite element (FE) model of the approach pavement was created to determine pavement deformation under moving load and stress state next to the bridge joint. The influence of insufficient support of the top asphalt layers on pavement response was investigated. The analysis of the cracks shows that some errors were made both during the design process and construction of the bridge approach pavement.

  • Non-destructive Testing of Wooden Elements
    • Monika Zielińska
    • Magdalena Rucka
    2021 Full text IOP Conference Series: Materials Science and Engineering

    Examining the condition of wooden elements is crucial from the perspective of proper structure performance. If the deterioration in the internal wood condition, which displays no symptoms visible from the outside, is detected, the further spread of the deterioration can be prevented. Test results often point to the necessity of conducting repairs and, renovations, replacing the structure of wooden beams, or even substituting a significant part of the structure. To achieve acceptable results, test methods should take into account the anisotropic nature of wood, which includes the shape of annual rings, as well as the location of the core in crosssection. To adopt methods based on physical effects, profound knowledge of wood physics is needed, particularly of interdependence. Apart from simple tests such as a visual inspection or tapping that are used to determine near-surface defects, non-destructive testing (NDT) plays an important role in the process. This paper presents the methods of non-destructive testing of wooden elements. These methods include tests conducted with ground penetrating radar (GPR), thermal techniques, microwaves, acoustic emission, ultrasonic tomography, and X-ray tomography. The paper summarises the use of non-destructive methods, indicating their advantages, disadvantages as well as some limitations.

  • Nonlinear Free and Forced Vibrations of a Hyperelastic Micro/Nanobeam Considering Strain Stiffening Effect
    • Amin Alibakhshi
    • Shahriar Dastjerdi
    • Mohammad Malikan
    • Victor Eremeev
    2021 Full text Nanomaterials

    In recent years, the static and dynamic response of micro/nanobeams made of hyperelasticity materials received great attention. In the majority of studies in this area, the strain-stiffing effect that plays a major role in many hyperelastic materials has not been investigated deeply. Moreover, the influence of the size effect and large rotation for such a beam that is important for the large deformation was not addressed. This paper attempts to explore the free and forced vibrations of a micro/nanobeam made of a hyperelastic material incorporating strain-stiffening, size effect, and moderate rotation. The beam is modelled based on the Euler–Bernoulli beam theory, and strains are obtained via an extended von Kármán theory. Boundary conditions and governing equations are derived by way of Hamilton’s principle. The multiple scales method is applied to obtain the frequency response equation, and Hamilton’s technique is utilized to obtain the free undamped nonlinear frequency. The influence of important system parameters such as the stiffening parameter, damping coefficient, length of the beam, length-scale parameter, and forcing amplitude on the frequency response, force response, and nonlinear frequency is analyzed. Results show that the hyperelastic microbeam shows a nonlinear hardening behavior, which this type of nonlinearity gets stronger by increasing the strain-stiffening effect. Conversely, as the strain-stiffening effect is decreased, the nonlinear frequency is decreased accordingly. The evidence from this study suggests that incorporating strain-stiffening in hyperelastic beams could improve their vibrational performance. The model proposed in this paper is mathematically simple and can be utilized for other kinds of micro/nanobeams with different boundary conditions.

  • Nonlinear Interaction of Magnetoacoustic Modes in a Quasi-Isentropic Plasma Flow
    • Anna Perelomova
    2021 Full text Archives of Acoustics

    The nonlinear interaction of magnetoacoustic waves in a plasma is analytically studied. A plasma is an open system. It is affected by the straight constant equilibrium magnetic flux density forming constant angle with the wave vector which varies from 0 till . The nonlinear instantaneous equation which describes excitation of secondary wave modes in the field of intense magnetoacoustic perturbations is derived by use of projecting. There is a diversity of nonlinear interactions of waves in view of variety of wave modes, which may be slow or fast and may propagate in different directions. The excitation is analysed in the physically meaningful cases, that is: harmonic and impulsive exciter, oppositely or accordingly directed dominant and secondary wave modes.

  • Nonlinear resultant theory of shells accounting for thermodiffusion
    • Victor Eremeev
    • Wojciech Pietraszkiewicz
    2021 Full text CONTINUUM MECHANICS AND THERMODYNAMICS

    The complete nonlinear resultant 2D model of shell thermodiffusion is developed. All 2D balance laws and the entropy imbalance are formulated by direct through-the-thickness integration of respective 3D laws of continuum thermodiffusion. This leads to a more rich thermodynamic structure of our 2D model with several additional 2D fields not present in the 3D parent model. Constitutive equations of elastic thermodiffusive shells are discussed in more detail. They are formulated from restrictions imposed by the resultant 2D entropy imbalance according to Coleman–Noll procedure extended by a set of 2D constitutive equations based on heuristic assumptions.

  • Nonlocal elasticity analysis of moderately thick porous functionally graded plates in a hygro-thermal environment
    • Shahriar Dastjerdi
    • Mohammad Malikan
    • Rossana Dimitri
    • Francesco Tornabene
    2021 Full text COMPOSITE STRUCTURES

    This work performs a novel quasi three-dimensional (3D) bending analysis for a moderately thick functionally graded material (FGM) made of nanoceramics and metal powders, in presence of porosities due to some incorrect manufacturing processes. Such porosities can appear within the plate in two forms, namely, even and uneven distributions. The modeled system assumes a polymer matrix where both shear and transverse factors coexist. The bending equations are obtained by using the Hamiltonian principle. In order to apply the quantum effects for the nanosystem, the well-known nonlocal theory of Eringen is simply assumed, while checking for its numerical accuracy. A physically-consistent analysis of the nanostructures would investigate possible surrounding effects. Thus, the thermal and humidity influence is accounted for the 3D problem, whose governing equations are solved through a semi-analytical polynomial method (SAPM), as recently proposed in literature for different applications. The proposed method is based on a simple procedure with very accurate numerical outcomes, whose performance is checked against the available literature. After computing the deflection relations, a systematic study is performed for the bending response of nanoporous FGMs in a hygro-thermal surrounding environment, with promising results for practical applications.

  • Non-Newtonian Mathematics Instead of Non-Newtonian Physics: Dark Matter and Dark Energy from a Mismatch of Arithmetics
    • Marek Czachor
    2021 Full text Foundations of Science

    Newtonian physics is based on Newtonian calculus applied to Newtonian dynamics. New paradigms such as ‘modified Newtonian dynamics’ (MOND) change the dynamics, but do not alter the calculus. However, calculus is dependent on arithmetic, that is the ways we add and multiply numbers. For example, in special relativity we add and subtract velocities by means of addition β1⊕β2=tanh(tanh−1(β1)+tanh−1(β2)), although multiplication β1⊙β2=tanh(tanh−1(β1)⋅tanh−1(β2)), and division β1⊘β2=tanh(tanh−1(β1)/tanh−1(β2)) do not seem to appear in the literature. The map fX(β)=tanh−1(β) defines an isomorphism of the arithmetic in X=(−1,1) with the standard one in R. The new arithmetic is projective and non-Diophantine in the sense of Burgin (Uspekhi Matematicheskich Nauk 32:209–210 (in Russian), 1977), while ultrarelativistic velocities are super-large in the sense of Kolmogorov (Technika Molodezhi 10:16–19 (11:30–33 in Russian), 1961). Velocity of light plays a role of non-Diophantine infinity. The new arithmetic allows us to define the corresponding derivative and integral, and thus a new calculus which is non-Newtonian in the sense of Grossman and Katz (Non-Newtonian calculus, Lee Press, Pigeon Cove, 1972). Treating the above example as a paradigm, we ask what can be said about the set X of ‘real numbers’, and the isomorphism fX:X→R, if we assume the standard form of Newtonian mechanics and general relativity (formulated by means of the new calculus) but demand agreement with astrophysical observations. It turns out that the observable accelerated expansion of the Universe can be reconstructed with zero cosmological constant if fX(t/tH)≈0.8sinh(t−t1)/(0.8tH). The resulting non-Newtonian model is exactly equivalent to the standard Newtonian one with ΩΛ=0.7, ΩM=0.3. Asymptotically flat rotation curves are obtained if ‘zero’, the neutral element 0X of addition, is nonzero from the point of view of the standard arithmetic of R. This implies f−1X(0)=0X>0. The opposition Diophantine versus non-Diophantine, or Newtonian versus non-Newtonian, is an arithmetic analogue of Euclidean versus non-Euclidean in geometry. We do not yet know if the proposed generalization ultimately removes any need of dark matter, but it will certainly change estimates of its parameters. Physics of the dark universe seems to be both geometry and arithmetic.

  • Non-Satellite Broadband Maritime Communications for e-Navigation Services
    • Michał Hoeft
    • Krzysztof Gierłowski
    • Jacek Rak
    • Józef Woźniak
    • Krzysztof Nowicki
    2021 Full text IEEE Access

    The development of broadband network access technologies available to users on land has triggered a rapid expansion of a diverse range of services provided by terrestrial networks. However, due to limitations of digital communication technologies in the off-shore area, the maritime ICT systems evolution so far has not followed that trend. Despite the e-navigation initiative defining the set of Maritime Services, the progress in the maritime ICT systems evolution has been slow. Only a few systems, including the VHF Data Exchange System (VDES), or the TRI-Media Telematic Oceanographic Network (TRITON) have been proposed to extend the basic set of services offered by classical radio-communication solutions. However, all those systems have significant limitations. The purpose of this paper is to introduce the netBaltic system designed as a fully heterogeneous system for modern maritime communications. Its unique feature is the capability to transparently use different communication technologies to efficiently support maritime ICT services, as well as openness for the incorporation of future communication technologies. The paper presents an overview of VDES, TRITON and netBaltic systems and analysis showing their expected strengths and weaknesses. The systems are then compared in simulated environments, illustrating real-world usage scenarios based on real maritime traffic information and performance measurements obtained during off-shore measurement campaigns. Results indicate that netBaltic seems to be the most versatile one and is capable of offering access to all services defined by International Maritime Organization, due to its ability to use different communication technologies simultaneously and functionality offered by its Delay Tolerant Networking component.

  • Normalized Partial Scattering Cross Section for Performance Evaluation of Low-Observability Scattering Structures
    • Muhammad Abdullah
    • Sławomir Kozieł
    • Stanisław Szczepański
    2021 Full text Electronics

    The development of diffusion metasurfaces created new opportunities to elevate the stealthiness of combat aircraft. Despite the potential significance of metasurfaces, their rigorous design methodologies are still lacking, especially in the context of meticulous control over the scattering of electromagnetic (EM) waves through geometry parameter tuning. Another practical issue is insufficiency of the existing performance metrics, specifically, monostatic and bistatic evaluation of the reflectivity, especially at the design stage of metasurfaces. Both provide limited insight into the RCS reduction properties, with the latter being dependent on the selection of the planes over which the evaluation takes place. This paper introduces a novel performance metric for evaluating scattering characteristics of a metasurface, referred to as Normalized Partial Scattering Cross Section (NPSCS). The metric involves integration of the scattered energy over a specific solid angle, which allows for a comprehensive assessment of the structure performance in a format largely independent of the particular arrangement of the scattering lobes. We demonstrate the utility of the introduced metric using two specific metasurface architectures. In particular, we show that the integral-based metric can be used to discriminate between the various surface configurations (e.g., checkerboard versus random), which cannot be conclusively compared using traditional methods. Consequently, the proposed approach can be a useful tool in benchmarking radar cross section reduction performance of metamaterial-based, and other types of scattering structures.

  • Novel 1,2,3-Triazole Derivatives as Mimics of Steroidal System—Synthesis, Crystal Structures Determination, Hirshfeld Surfaces Analysis and Molecular Docking
    • Mateusz Daśko
    • Anna Dołęga
    • Magdalena Siedzielnik
    • Karol Biernacki
    • Olga Ciupak
    • Janusz Rachoń
    • Sebastian Demkowicz
    2021 Full text MOLECULES

    Herein, we present the synthesis and crystal structures determination of five 4-(1-phenyl-1H-1,2,3-triazol-4-yl)phenol derivatives containing halogen atoms, 6a–e, which may be used as an excellent mimic of steroids in the drug development process. Good quality crystals obtained for all of the synthesized compounds allowed the analysis of their molecular structures. Subsequently, the determined crystal structures were used to calculate the Hirshfeld surfaces for each of the synthesized compounds. Furthermore, results of our docking studies indicated that synthesized derivatives are able to bind effectively to the active sites of selected enzymes and receptors involved in the hormone biosynthesis and signaling pathways, analogously to the native steroids.

  • Novel “acid tuned” deep eutectic solvents based on protonated L-proline
    • Patrycja Janicka
    • Andrzej Przyjazny
    • Grzegorz Boczkaj
    2021 Full text JOURNAL OF MOLECULAR LIQUIDS

    The paper presents new types of deep eutectic solvents (DESs) based on L-proline protonated using three different acids (hydrochloric, sulfuric and phosphoric)and playing the role of a hydrogen bond acceptor(HBA). Glucose and xylitol were used as hydrogen bond donors (HBD). A series of deep eutectic solvents with various mole ratios were obtained for the systems L-proline: glucose and L-proline: xylitol. Density, melting point, pH and viscosity of the synthesized DESs were determined along with the effect of water content, mole fraction of the HBA in DES and temperature on properties of the DESs. A wide range of densities (1343-1606 kg/m3), viscosities at 20°C (699.6-48,590 mPa·s) and pH of 0.1M DES solutions (1.578-2.456) make the obtained deep eutectic solvents potentially applicable in numerous technological processes, extractions as well as in analytical techniques, including microextraction. Components of these DESs are of natural origin and non-toxic, thus environmentally friendly and suitable for food as well as pharmaceutical industry.

  • Novel analytical approach for real-time monitoring of volatile Maillard reaction products emitted from the sugar-amino acid model system using proton transfer reaction mass spectrometry
    • Anna Banaszkiewicz
    • Tomasz Majchrzak
    2021

    In the presented research, volatile Maillard reaction products formation in the two sugar-amino acid model systems, namely glucoselysine and ribose-lysine model systems were investigated using proton transfer reaction mass spectrometry. Obtained data were supported by the reference method, i.e., UV/Vis spectrometry. A number of volatile organic compounds were selected based on the correlation of the effect of Maillard reaction conditions and model system concentration with the emission of characteristic volatiles. It was demonstrated that the ribose-lysine model system was more reactive than the glucose-lysine model system which resulted in the high concentration of volatiles, such as acetonitrile, acetaldehyde, and 2,3-pentanedione. Characteristic volatile Maillard reaction products were observed only in the ribose–lysine model system: 2,3-butanedione and 3-methylbutanal, while methylfuran was characteristic for the glucose–lysine model system. Absorbance measurements revealed a correlation between the browning of the model systems and the emission of selected volatile Maillard reaction products

  • Novel Cast Polyurethanes Obtained by Using Reactive Phosphorus-Containing Polyol: Synthesis, Thermal Analysis and Combustion Behaviors
    • Izabela Zagożdżon
    • Paulina Parcheta
    • Janusz Datta
    2021 Full text Materials

    Phosphorus-containing polyol applications in polyurethane synthesis can prevent volatilization of flame retardants and their migration on the surface of a material. In this work, novel cast polyurethanes were prepared by a one-step method with the use of different amounts of phosphorus-containing polyol, 4,4′–diphenylmethane diisocyanate and 1,4-butanediol. The chemical structure, thermal, physicochemical and mechanical properties and flame resistance of the prepared materials were investigated. The results obtained for cast flame-retarded polyurethanes were compared with cast polyurethane synthesized with commonly known polyether polyol. It has been shown that with an increasing amount of phosphorus content to polyurethane’s chemical structure, an increased flame resistance and char yield were found during combustion tests. Phosphorus polyol worked in both the condensed (reduced heat and mass exchange) and gas phase (inhibition of flame propagation during burning). The obtained materials contained phosphorus polyol, indicating higher thermal stability in an oxidative environment than an inert atmosphere.

  • Novel Cold Crucible Ultrasonic Atomization Powder Production Method for 3D Printing
    • Łukasz Żrodowski
    • Rafał Wróblewski
    • Tomasz Choma
    • Bartosz Morończyk
    • Mateusz Ostrysz
    • Marcin Leonowicz
    • Wojciech Łacisz
    • Piotr Błyskun
    • Jan S. Wróbel
    • Grzegorz Cieślak
    • Bartłomiej Wysocki
    • Cezary Żrodowski
    • Karolina Pomian
    2021 Full text Materials

    : A new powder production method has been developed to speed up the search for novel alloys for additive manufacturing. The technique involves an ultrasonically agitated cold crucible installed at the top of a 20 kHz ultrasonic sonotrode. The material is melted with an electric arc and undergoes pulverization with standing wave vibrations. Several different alloys in various forms, including noble and metallic glass alloys, were chosen to test the process. The atomized particles showed exceptional sphericity, while powder output suitable for additive manufacturing reached up to 60%. The AMZ4 metallic glass powder remained amorphous below the 50 μm fraction, while tungsten addition led to crystallization in each fraction. Minor contamination and high Mn and Zn evaporation, especially in the finest particles, was observed in atomized powders. The innovative ultrasonic atomization method appears as a promising tool for material scientists to develop powders with tailored chemical composition, size and structure.

  • Novel Diazocrowns with Pyrrole Residue as Lead(II) Colorimetric Probes
    • Błażej Galiński
    • Elżbieta Luboch
    • Jarosław Chojnacki
    • Ewa Wagner-Wysiecka
    2021 Full text Materials

    Novel 18- and 23-membered diazomacrocycles were obtained with satisfactory yields by diazocoupling of aromatic diamines with pyrrole in reactions carried under high dilution conditions. X-ray structure of macrocycle bearing five carbon atoms linkage was determined and described. Compounds were characterized as chromogenic heavy metal ions receptors. Selective color and spectral response for lead(II) was found in acetonitrile and its mixture with water. Complexation properties of newly obtained macrocycles with a hydrocarbon chain were compared with the properties of their oligoether analogs. The influence of the introduction of hydrocarbon residue as a part of macrocycle on the lead(II) binding was discussed. Selective and sensitive colorimetric probe for lead(II) in aqueous acetonitrile with detection limit 56.1 mg/L was proposed.

  • Novel fast non-linear electrochemical impedance method for corrosion investigations
    • Paweł Ślepski
    • Michał Szociński
    • Grzegorz Lentka
    • Kazimierz Darowicki
    2021 MEASUREMENT

    The paper presents a novel approach to corrosion rate monitoring using non-linear electrochemical impedance spectroscopy. The authors propose a new variant of non-linear impedance measurement using amplitude-modulated multi-frequency ac perturbation signal. It allows shortening of measurement duration so it is possible to monitor corrosion rate of the systems experiencing rapid changes. In this way a limitation resulting from lack of stationarity condition during the impedance measurements is overcome. Potentialities of the proposed method were presented on the example of carbon steel corrosion in 1 M HCl solution. Sudden changes in the corrosion rate were induced by injection of urotropine as a corrosion inhibitor. The investigations provided time-evolution of charge transfer resistance and corrosion current, clearly reflecting the changes occurring in the investigated system triggered by the inhibitor introduction. Obtained corrosion current values were in a good agreement with the ones acquired using classic method of polarization in the Tafel range.

  • Novel hierarchical nonlinear control algorithm to improve dissolved oxygen control in biological WWTP
    • Robert Piotrowski
    • Hubert Sawicki
    • Konrad Żuk
    2021 Full text JOURNAL OF PROCESS CONTROL

    Wastewater treatment is a problem known to humankind for centuries. The quality of treated sewage determines the condition of reservoirs around the world. Control of such a complex and nonlinear system as a wastewater treatment plant requires thorough knowledge of the process. The paper presents a hierarchical control system of a Sequencing Batch Reactor (SBR) in Wastewater Treatment Plant (WWTP) taking into account a model based on actual measurements taken from a WWTP in Swarzewo, Poland. The authors designed and implemented a nonlinear model predictive controller (MPC) that allows for the optimal implementation of the desired DO level while minimising the operation of actuators (aeration system). The design description of the predictive controller was associated with the need to specify the performance function and define the optimisation problem. In a two-layer structure, a supervisory controller was implemented based on an actual time-based controller in Swarzewo WWTP. The overview showed the improved performance of the treatment plant and the versatility of the created solution. Results of simulation tests for the wastewater treatment plant case study are presented.

  • Novel insights into conjugation of antitumor-active unsymmetrical bisacridine C-2028 with glutathione: characteristics of non-enzymatic and glutathione S-transferase-mediated reactions
    • Agnieszka Potęga
    • Michał Kosno
    • Zofia Mazerska
    2021 Full text Journal of Pharmaceutical Analysis

    Unsymmetrical bisacridines (UAs) are a novel potent class of antitumor-active therapeutics. A significant route of phase II drug metabolism is conjugation with glutathione (GSH), which can be non-enzymatic and/or catalyzed by GSH-dependent enzymes. The aim of this work was to investigate the GSH-mediated metabolic pathway of a representative UA, C 2028. GSH supplemented incubations of C-2028 with rat, but not with human, liver cytosol led to the formation of a single GSH-related metabolite. Interestingly, it was also revealed with rat liver microsomes. Its formation was NADPH-independent and was not inhibited by co-incubation with the cytochrome P450 inhibitor 1-aminobenzotriazole. Therefore, the direct conjugation pathway occurred without the prior P450-catalyzed bioactivation of the substrate. In turn, incubations of C-2028 and GSH with human recombinant GSTP1-1 or with heat-/ethacrynic acid-inactivated liver cytosolic enzymes resulted in the presence or lack of GSH conjugated form, respectively. These findings proved the necessary participation of glutathione S-transferase (GST) in the initial activation of the GSH thiol group to enable a nucleophilic attack on the substrate molecule. Another C-2028-GSH S-conjugate was also formed during non-enzymatic reaction. Both GSH S-conjugates were characterized by combined liquid chromatography/tandem mass spectrometry. Mechanisms for their formation were proposed. The ability of C-2028 to GST mediated and/or direct GSH conjugation is suspected to be clinically important. This may affect the patient’s drug clearance due to GST activity, loss of GSH, or the interactions with GSH conjugated drugs. Moreover, GST mediated depletion of cellular GSH may increase tumor cell exposure to reactive products of UA metabolic transformations.

  • Novel luminescent calixarene-based lanthanide materials: From synthesis and characterization to the selective detection of Fe3+
    • Ilária Martina Silva Lins
    • José Daniel da Silva Fonseca
    • Leonis Lourenço
    • Jarosław Chojnacki
    • Severino Júnior
    • Bráulio Barros
    • Joanna Kulesza
    2021 JOURNAL OF SOLID STATE CHEMISTRY

    Calix[n]arene-based coordination networks are an emerging class of materials with intriguing properties resulted from the presence of the cavity-like structure of the macrocycle and metallic nodes. In this work, four novel luminescent materials based on calix[4]arene-carboxylate and lanthanides (Eu3þ and Tb3þ) were prepared by two synthetic approaches, solvothermal (CDA-Eu-ST) and slow diffusion (CDA-Eu-RT, CDA-Tb-RT, CTA-Tb-complex) methods. The coordination networks were characterized by PXRD, FTIR, SEM and solid-state photoluminescence, and the results indicated the formation of two different CDA-Eu-structures governed by the synthesis parameters. Single-crystal X-ray diffraction of CTA-Tb-complex revealed the formation of a new dinuclear complex of calix[4] arene-tetracarboxylate containing Naþ and Tb3þ coordinated within the lower rim of the molecule. Preliminary studies showed that CDA-Eu-RT was capable of selectively sensing Fe3þ ions in water via quenching the luminescence, demonstrating the possibility of using calix[4]arene-based platforms as efficient luminescent sensors

  • Novel molecules containing structural features of NSAIDs and 1,2,3-triazole ring: Design, synthesis and evaluation as potential cytotoxic agents
    • Jyoti Mareddy
    • Kazi Hossain
    • N. Sudhakar Yadav
    • Venkanna Banothu
    • Jaya Shree Anireddy
    • Sarbani Pal
    2021 Full text JOURNAL OF MOLECULAR STRUCTURE

    For the first time the template containing structural features of more than one NSAIDs and the 1,2,3-triazole ring was explored for the identification of potential cytotoxic agents. These new and complex molecules were predicted to be effective inhibitors of PDE4B by molecular modelling studies in silico. The multi-step synthesis of these compounds were carried out starting from the well-known drug nimesulide and involved the use of coppercatalyzed azide-alkyne cycloaddition (CuAAC) approach as the key step. Mainly two types of compounds e.g. 1- aryl-1H-1,2,3-triazoles and N-aryl-2-(1H-1,2,3-triazol-1-yl)acetamide derivatives were synthesized by using this method in good yields. The in vitro screening of these compounds against two cancer cell lines e.g. HCT-15 (human colon cancer cell line) and NCI-H226 (human lung cancer cell line) using a colorimetric MTT assay allowed identification of two preliminary hit molecules i.e. 8a and 8f. The SAR (Structure Activity Relationship) analysis indicated that the presence of an amide linker between the aryl ring and the 1,2,3-triazole moiety was favorable for the activities. The compound 8a and 8f showed significant inhibition of PDE4B in vitro and good interactions with this protein in silico suggesting PDE4B as their potential target. The usefulness and concerns of these molecules in the light of computational ADME prediction were analyzed. Overall, novel molecules were identified as potential cytotoxic agents for further study.

  • Novel Research on Biomedical Polyurethanes
    • Józef Haponiuk
    • Justyna Kucińska-Lipka
    • Paweł Szarlej
    • Przemysław Gnatowski
    2021

    The variety of mechanical properties characterizes properly designed PURs. They may be biocompatible and reveal compatibility with blood, making them attractive materials for the fabrication of tissue scaffolds; however, like all synthetic materials, PURs don’t reveal sufficient biocompatibility. PURs may undergo certain chemical modifications (e.g., 1,4:3,6-dianhydro-D-sorbitol, ascorbic acid (AA), growth factors, covering with gelatin, plasma modifications to impart them the bioactivity. In the regeneration of soft and hard tissues, as well as in cardiovascular system regeneration, more common have become the scaffolds - three-dimensional (3D), porous structures, which are biological substitutes enabling for regeneration, maintenance, and improvement of tissues functions representing mechanical properties suitable to support regenerated tissue. Moreover, in specific applications, it is required that such material, after application to the human body, undergo gradual degradation, at a rate directly proportional to the growth of the reconstructed tissue, and the degradation products cannot be harmful and toxic for the system. The tissue scaffolds degradation rate, according to the literature, has to be controlled in a way that the tissue scaffold maintains its physicochemical and mechanical properties for at least 3-6 months. Searching for new materials of described characteristic lead me to undertake the design of new PUR systems, which will be undergoing degradation and at the same time will be biocompatible and of physicochemical, mechanical, and thermal properties suitable for this purpose. In the literature was reported an application of aromatic diisocyanates for PUR synthesis, which are used for the fabrication of tissue scaffolds. Such materials, after long-term in vitro interaction with the living tissues, undergo degradation to the harmful for the living system aromatic diamines. In performed studies, we have applied aliphatic and cycloaliphatic diisocyanates (1,6-hexamethylene diisocyanate (HDI) and 4,4’-methylene bis(cyclohexyl isocyanate) (HMDI), which degradation products (in the living system) are nontoxic amines removable from the system in natural life cycles .In our research we were using an amorphous α,ω-dihydroxy(ethylene-butylene adipate) macrodiol (PEBA) to improve the degradation behavior of PURs and tissue scaffolds fabricated with their use, and we proposed modificators of their biological properties.

  • Novel staphylococci nucH taxonomical marker used in identification of human-associated Staphylococcus succinus subsp. casei
    • Katarzyna Garbacz
    • Roman Kotłowski
    • Ewa Kwapisz
    2021 Environmental Microbiology Reports

    The aim of our study was to assess the sequencing of unique nucH gene fragment based on performed bioinformatics analysis as a novel diagnostic method for the identification of difficult to identify staphylococcal human pathogenic strains. Initially, PCR-RFLP-rrn analysis specific to the spacers between 16SrDNA and 23SrDNA followed by HhaI restriction analysis was performed. Further, sequencing of nucH and 16S rDNA genes fragments was carried out. Blast analysis from the NCBI showed 99% similarity of nucH gene fragment with reference genomic DNA for S. succinus with the accession no. CP018199. This result was also confirmed by MALDI-TOF analysis. Sequencing analysis of 16S rDNA gene fragment allowed for 100% identification of two strains isolated from human samples as Staphylococus succinus subsp. casei. Sequencing of identified unique nucH gene fragment seems to be a promising diagnostic assay for the identification of Staphylococcus species. Based on our results, we can assume that probably other Staphylococcus species originated from different clinical samples could be identified using nucH gene sequencing method we developed. However, an extension of the genetic databases with a substantially bigger number of reference staphylococcal species for nucH gene is needed to make this method better than widely used standard 16S rDNA sequencing assay. To the best of our knowledge, it is the second published isolation of S. succinus subsp. casei from human clinical specimens. Moreover, possibility of decreasing the number of dimensions from multi-PCR-bands results using ribotyping analysis is also described.

  • Novel strategies to enhance hydrodynamic cavitation in a circular venturi using RANS numerical simulations
    • Nilanjan Dutta
    • Prasad Kopparthi
    • Asim Kumar Mukherjee
    • Neelkanth Nirmalkar
    • Grzegorz Boczkaj
    2021 WATER RESEARCH

    Hydrodynamic cavitation is a popular advanced oxidation technique and it has received wide range of applications from waste water treatment to the nanoparticles synthesis in recent years. The enhancement of the intensity of the hydrodynamic cavitation is always been an emerging field of research. Within this framework, we have proposed and investigated three distinct strategies to enhance the intensity of cavitation in a circular venturi, namely, (1) by introducing the surface roughness on the wall (2) single or multiple circular hurdles in the diverging section (3) By modifying the diverging section from planer to the trumpet shape. RANS (Reynolds Averaged Navier-Stokes) based numerical simulations are carried out the over wide range of conditions: (pressure ratio), (half divergent angle), (half convergent angle), and (throat length). An extensive numerical and experimental validation with the literature have been presented to ensure the reliability and accuracy of present work. Detailed results on velocity fields, local and average volume fraction, pressure loss coefficients, cavitation number, discharge coefficient and pressure distribution are reported as function of dimensionless parameters. Five designs of various combinations of surface roughness, circular hurdles, and trumpet diverging section have been compared. The effect of surface roughness on trumpet diverging wall has been observed to be more pronounced than the other designs. Trumpet diverging wall with surface roughness is found to be optimum for the practical applications.

  • Novel Structures and Applications of Graphene-Based Semiconductor Photocatalysts: Faceted Particles, Photonic Crystals, Antimicrobial and Magnetic Properties
    • Marcin Janaczek
    • Maya Endo-Kimura
    • Zhishun Wei
    • Zuzanna Bielan
    • Tharishinny R. Mogan
    • Tamer M. Khedr
    • Kunlei Wang
    • A. Markowska-Szczupak
    • Kowalska Ewa
    • Agata Markowska-Szczupak
    2021 Full text Applied Sciences

    Graphene, graphene oxide, reduced graphene oxide and their composites with various compounds/materials have high potential for substantial impact as cheap photocatalysts, which is essential to meet the demands of global activity, offering the advantage of utilizing “green” solar energy. Accordingly, graphene-based materials might help to reduce reliance on fossil fuel supplies and facile remediation routes to achieve clean environment and pure water. This review presents recent developments of graphene-based semiconductor photocatalysts, including novel composites with faceted particles, photonic crystals, and nanotubes/nanowires, where the enhancement of activity mechanism is associated with a synergistic effect resulting from the presence of graphene structure. Moreover, antimicrobial potential (highly needed these days), and facile recovery/reuse of photocatalysts by magnetic field have been addresses as very important issue for future commercialization. It is believed that graphene materials should be available soon in the market, especially because of constantly decreasing prices of graphene, vis response, excellent charge transfer ability, and thus high and broad photocatalytic activity against both organic pollutants and microorganisms.

  • Novel two-step synthesis method of thin film heterojunction of BiOBr/Bi2WO6 with improved visible-light-driven photocatalytic activity
    • Anna Pancielejko
    • Justyna Łuczak
    • Wojciech Lisowski
    • Adriana Zaleska-Medynska
    • Paweł Mazierski
    2021 Full text APPLIED SURFACE SCIENCE

    A novel two-step ionic liquid assisted procedure was applied for a controllable synthesis of BiOBr/Bi2WO6 heterojunction thin films. The preparation route involved an anodic oxidation of tungsten foil and hydrothermal transformation of as-anodized oxide in the presence of bismuth precursor and ionic liquid, N-butylpyridinium bromide [BPy][Br]. The BiOBr plates with irregular shapes adhered to the surface of flower-like Bi2WO6 and formed a heterojunction between BiOBr and Bi2WO6, as confirmed by the analysis of their structure and composition. The highest efficiency of phenol degradation was achieved when the highest amount of IL was used (the apparent quantum efficiency was almost 8 and 71.5 times higher compared to BiOBr and Bi2WO6, respectively). In addition, superoxide radicals (•O2–) were found as the main factor responsible for the photodegradation. A possible reaction mechanism was further investigated as a function of monochromatic irradiation to determine the exact range of the composite photoactivity.

  • Nowe kierunki usuwania azotu w oczyszczalniach ścieków
    • Dominika Sobotka
    • Katarzyna Hrynkiewicz
    • Marcin Marcinkowski
    • Joanna Majtacz
    • Dominika Grubba
    • Jacek Mąkinia
    2021 Forum Eksploatatora

    W 2015 roku Komisja Europejska przyjęła nową strategię gospodarki o obiegu zamkniętym (ang. Circular Economy), której celem jest efektywne wykorzystanie zasobów, a także zwiększenie roli gospodarki odpadami. Działania prowadzone w ostatnich latach w sektorze oczyszczania ścieków były ukierunkowane na rozwój efektywnej, niskoemisyjnej gospodarki zasobami, sprzyjającej wzrostowi bezpieczeństwa energetycznego i poprawie stanu jakości wód. Działania te spowodowały zmianę paradygmatu, zgodnie z którym ścieki, zarówno komunalne jak i powstające w trakcie procesów produkcyjnych, traktowane są jako źródło energii i surowców, takich jak woda, biogeny czy związki organiczne.

  • Nowe sposoby instrumentalnego określania wybranych cech zapachu za pomocą technik czujnikowych
    • Bartosz Szulczyński
    2021 Full text

    Rozprawa doktorska zawiera opis rozwoju nowych metod instrumentalnego określania wybranych cech zapachu za pomocą technik czujnikowych (elektronicznych nosów). Jest ona oparta na sześciu artykułach opublikowanych w recenzowanych czasopismach naukowych. Głównym celem tej pracy było określenie możliwości wykorzystania elektronicznego nosa do instrumentalizacji pomiaru wybranych cech zapachu – intensywności i jakości hedonicznej, z uwzględnieniem występujących w badanych mieszaninach interakcji zapachowych. Badania prowadzono z wykorzystaniem samodzielnie zaprojektowanych i skonstruowanych prototypów elektronicznych nosów, a uzyskane wyniki porównywano z wynikami analizy sensorycznej oraz wartościami teoretycznymi obliczonymi z wykorzystaniem modeli percepcyjnych i psychofizycznych. Jako metody analizy danych stosowano regresję głównych składowych, sztuczne sieci neuronowe oraz logikę rozmytą. Zastosowanie tych metod pozwoliło również określać interakcje zapachowe występujące w badanych próbkach, które pokrywają się w ponad 75% ze wskazaniami panelu sensorycznego. Opracowaną sztuczną sieć neuronową wykorzystano do monitorowania procesu dezodoryzacji powietrza metodą biofiltracji ze złożem zraszanym.

  • Nowe technologie w procesie projektowania architektonicznego
    • Jan Cudzik
    2021 Zawód: Architekt

    Projektowanie architektoniczne zmienia się wraz z wprowadzaniem nowych technologii. Zmiany, które są wynikiem cyfrowej rewolucji z końca XX wieku przyczyniły się do zmiany metod stosowanych w projektowaniu, ale nie sposobu myślenia o projektach i ich etapach. Można stwierdzić, że tradycyjna deska kreślarska została zastąpiona cyfrową. Jednak dziś w związku ze wzrostem skomplikowania procesów projektowych, ich wielowarstwowości oraz rosnącymi możliwościami komputacyjnymi, możemy projektować bardziej efektywnie i dokładnie. Badacz architektury cyfrowej Wasim Jabi zauważa, że projektowanie jest z natury rzeczy iteracyjne, każda nowa tura stawie pytania i odpowiedzi, na które wpływają później na uzyskiwany efekt przestrzenny. Ciągłe modyfikowanie projektu jest więc konieczne, a bez zastosowania form automatyzacji w projekcie jest to czasochłonne i często przyczynia się do powstawania błędów. Co więcej, im bardziej zaawansowany projekt i jego etap, tym czas konieczny na zmiany oraz prawdopodobieństwo wystąpienia błędu znacząco wzrasta. Projekt zbudowany o zasady algorytmiczne pozwala na wprowadzanie dowolnych zmian w projekcie na każdym etapie jego tworzenia bez konieczności ręcznego przerysowywania, czy modelowania każdej z jego wersji. Powyższe zmiany zachodzące w architekturze są zauważalne na różnych etapach procesu projektowego, a ich skalę dekadę temu potrafiło ocenić niewielu. Dziś ta świadomość jest już większa, ale z uwagi na ciągły rozwój narzędzi wymaga ciągłej nauki i otwartości.

  • Numerical and experimental study on effect of boundary conditions during testing of stiffened plates subjected to compressive loads
    • Krzysztof Wołoszyk
    • Yordan Garbatov
    • Jakub Kowalski
    • Leszek Samson
    2021 Full text ENGINEERING STRUCTURES

    This study analyses the effect of boundary conditions during testing on the structural behaviour stiffened plates with different thicknesses subjected to compressive loads. The goal of the compressive tests is to analyse the ultimate strength of a stiffened plate. During the test, relevant physical quantities are measured and investigated. The supporting structure's behaviour is investigated by analysing the force-displacements relationship and post-collapse shapes of tested specimens. The experimental results are compared with the ones made by FE analyses. The FE model is explored in two variants, considering clamped and simply supported boundary conditions. A detailed comparison of the lateral deflections of plates near the supports is also performed. The analysis has shown that nearly clamped boundary conditions were achieved during the test, leading to an almost complete restriction of plate rotations during the experimental testing, which complies with the real ship structural behaviour of similar components when deep girders transversally support them.

  • Numerical Estimation of Hull Hydrodynamic Derivatives in Ship Maneuvering Prediction
    • Radosław Kołodziej
    • Paweł Hoffmann
    2021 Full text Polish Maritime Research

    Prediction of the maneuvering characteristics of the ship at the design stage can be done by means of model tests, computational simulations or a combination of both. The model tests can be realized as direct simulation of the standard maneuvers with the free running model, which gives the most accurate results, but is also the least affordable as it requires very large tank or natural lake, as well as complex equipment of the model. Alternatively, captive model test can be used to identify the hydrodynamic characteristics of the hull which can be used to simulate the standard maneuvers with the use of dedicated software. Two types of captive model tests are distinguished: circular motion tests (CMT) and planar motion mechanism tests (PMM). The paper presents an attempt on developing computational method for ship maneuverability prediction in which the hydrodynamic characteristics of the hull are identified by means of computational fluid dynamics (CFD). The CFD analyses presented here simulate directly the circular motion test. The resulting hull characteristics are verified against the available literature data, and the results of the simulations are verified against the results of free running model tests. Reasonable agreement shows large potential of the proposed method.

  • NUMERICAL ESTIMATION OF HULL HYDRODYNAMIC DERIVATIVES IN SHIP MANOUVERING PREDICTION
    • Radosław Kołodziej
    • Paweł Hoffmann
    2021

    Operating in crowded waterways pose a risk of accidents and disasters due to maneuvering limitations of the ship. In order to predict ship’s maneuvering characteristics at the design stage, model tests are often executed as the most accurate prediction tool. Two approaches can be distinguished here: free running model tests and numerical simulations based on planar motion model with the use of hydrodynamic derivatives obtained from captive model tests. However, although the model tests give very accurate prediction of ship’s maneuvering performance, they are often not affordable both due to the cost and due to their duration, making them less efficient in iterative design process. Thus, CFD simulations became one of the most commonly used research methods in ship hydrodynamics, offering reasonable compromise between the accuracy and the cost. Along with continuously improving computing power and increasingly accurate numerical methods, it became possible to develop new ways of assessing ship maneuvering performance with the use state of the art CFD tools. The purpose of this paper is to present one of such methods which is established for practical use in design process of a ship. The analysis is focused on evaluation of hydrodynamic derivatives for the hull based on CFD simulation equivalent to the rotating arm test - one of the variants of captive tests. The results are verified versus the results of model tests carried out in Maritime Advanced Research Centre CTO S.A. with the use of planar motion mechanism - PMM.

  • Numerical evaluation of dynamic response of an experimentally tested base-isolated and fixed-base steel structure model
    • Tomasz Falborski
    • Tomasz Jaroszewski
    • Robert Jankowski
    2021 Full text

    Seismic isolation is recognized as one of the most popular and effective methods of protecting structures during earthquake. The present paper is focused on the comparison be-tween the dynamic responses of buildings with fixed and isolated bases exposed to seismic exci-tations. The aim of the study is to investigate the effectiveness of a simplified base isolation numerical modelling technique using the linear springs. One-storey steel structure model has been considered using ETABS software, which was previously tested during the shaking table tests. The comparison of the structural response has been performed between the numerical and experimental results. High compatibility of the results for the fixed-base steel model between the numerical and experimental analyses has been obtained which proves the effectiveness of the modelling techniques used in the ETABS software. It has also been found that the isolation system is effective in improving the response of the steel structure during earthquake. However, modelling the isolation system using the linear springs is not an accurate technique due to the large differences in the structural responses obtained between the numerical and experimental analyses.

  • Numerical investigation on distribution characteristics of oxidation air in a lime slurry desulfurization system with rotary jet agitators
    • Longhao Xiang
    • Xun Sun
    • Xuesong Wei
    • Guichao Wang
    • Grzegorz Boczkaj
    • Joon Yong Yoon
    • Songying Chen
    2021 Full text CHEMICAL ENGINEERING AND PROCESSING

    Rotary jet agitator is an effective device for mixing, dispersing, dissolving, and suspending dispersed phases in liquid, and is particularly advantageous to the homogenization of oxygen-enriched air within the lime slurry desulfurization system. The distribution of oxygen-enriched air in agitators is vital for the process of gypsum crystallization and the homogeneous and sufficient oxygen-enriched air can promote the formation of an economically useful by-product. The present study investigated the diffusion performance of oxygen-enriched air in a rotary jet agitator during the wet flue gas desulfurization process by utilizing computational fluid dynamics. The consistency of numerical and experimental results is validated under identical conditions. Investigation results show that the rotation velocities and the inlet velocities of rotary jet machines significantly affect the distribution and homogeneity of the oxygen-enriched air distribution. However, these effects deteriorate with increasing rotation angular and jet outlet velocities. Under the optimal condition, the oxygen-enriched air concentration, within the cross-sections, fluctuates by approximately 20%. The Rotary jet agitator appears to be a remarkable method for the homogenization of oxygen-enriched air in the lime slurry tank, and in other gas-liquid stirring tanks, due to its high efficacy and good stirring effect.

  • Numerical Model of Surface and Quasi-Spherical Sea Noise and Its Application to Analysis of DIFAR Systems
    • Mariusz Rudnicki
    • Roman Salamon
    • Jacek Marszal
    2021 Full text Archives of Acoustics

    Various types of passive sonar systems are used to detect submarines. These activities are complex and demanding. Therefore, computer simulations are most often used at the design stage of these systems. For this reason, it is also necessary to simulate the acoustic ambient noise of the sea. The article proposes a new numerical model of surface and quasi-spherical sea noise and presents its statistical parameters. The results of the application of the developed noise model to analyse the received signals of the DIFAR1 sonobuoy are also presented.

  • Numerical Model of the Aortic Valve Implanted Within Real Human Aorta
    • Marcin Nowak
    • Wojciech Adamczyk
    • Bartlomiej Melka
    • Ziemowit Ostrowski
    • Ryszard Bialecki
    2021

    Cardiovascular system diseases are the main cause of deaths in developed and developing countries. The main reasons are myocardial infarction, heart failure, stroke and valvular diseases. These are caused mainly by arteriosclerosis. The valvular diseases involve a significant burden for the health care system and their frequency is rising with the patient age. This work describes the tools and numerical models appropriate for modeling the blood flow through the synthetic aortic valve and demonstrates the preliminary model used by authors. The overset mesh technique was applied to capture synthetic valve movement implanted within the aortic root, the aorta arch and the main branches of cardiovascular system. As the analyzed geometry scope does not include the whole cardiovascular system, there are artificial boundaries present at the inlet and at the outlets. To capture the cardiac system influence on the pressure values at these boundaries, the lumped parameter model was implemented.

  • Numerical modelling of the mesofracture process of sintered 316L steel under tension using microtomography
    • Michał Doroszko
    • Andrzej Seweryn
    2021 Full text ENGINEERING FRACTURE MECHANICS

    This paper concerns numerical modelling of the deformation process, taking into account the local fracture of porous 316L sinters at the mesoscopic scale using the finite element method. Calculations are performed with the use of geometrical models, to map the realistic shape of the porous mesostructure of the material, obtained by means of computed microtomography. The microtomographic device has limited and insufficient measurement accuracy for materials such as the porous sinters studied. For this reason, a method to compensate the inaccuracy of mesostructure shape-mapping is used in the numerical modelling of the deformation and fracture process of the material. The normalised Cockroft-Latham ductile fracture criterion is used to model the local fracture process (at the mesostructure level) of porous metal sinters under tension. The paper describes the numerical modelling procedure and the results of the calculations. The influence of the material structure on the meso-scale fracture process is also discussed. The numerical nominal stress–strain curves are compared with the results of experimental testing. The analysis of stress and strain fields and their variability caused by local fracture in the investigated heterogeneous material is also carried out.

  • Numerical simulation of natural convection of Glycol-Al2O3 nanofluids from a horizontal cylinder
    • Dorota Sawicka
    • Albert Baars
    • Janusz Cieśliński
    • Sławomir Smoleń
    2021 Full text HEAT TRANSFER ENGINEERING

    This paper deals with natural convection around a circular cylinder with constant heat flux in a cavity using computational fluid dynamics. As fluids ethylene glycol and a mixture of ethylene glycol with Al2O3 nanoparticles (mass concentrations of nanoparticles: 0.1% and 1%) are chosen. Rayleigh number ranges from 3104 to 3105. The nanofluids are modeled with single-phase approach. For the investigated range of nanoparticle concentration, the influence of concentration on Nusselt, Rayleigh number and heat transfer coefficient is small. Nevertheless, a slight shift toward lower Nusselt, Rayleigh numbers and an increase in heat transfer coefficient occur. The Nusselt number depends on Rayleigh number and only negligible on Prandtl number, which is in accordance with literature for Prandtl numbers of around 200. The numerically obtained results are compared with own preliminary experimental data, deviations are discussed.

  • Numeryczna analiza dynamiczna wieszaków w łukowym wiadukcie kolejowym. Analiza przypadku
    • Marek Bleja
    • Krzysztof Żółtowski
    2021 Full text Builder

    W artykule przedstawiono analizę dynamiczną wiaduktu kolejowego w ciągu Centralnej Magistrali Kolejowej zlokalizowanego koło Huty Zawadzkiej. W analizie zwrócono szczególną uwagę na lokalną odpowiedź wieszaków na obciążenie przejeżdżającym pociągiem oraz wiatrem. Obliczenia przeprowadzono na podstawie wykonanego modelu MES. Zweryfikowano poprawność modelu poprzez porównanie uzyskanych wyników z wartościami pomierzonymi. Przeprowadzono nieliniową analizę dynamiczną badania zachowania wieszaków. Następnie porównano amplitudy drgań wieszaka podczas przejazdu taboru oraz w sytuacji wzbudzenia wirami von Kármána. Analizy zostały przeprowadzone przy okazji realizacji pracy magisterskiej.

  • Numeryczna mechanika płynów
    • Krzysztof Tesch
    2021

    Numeryczna mechanika płynów

  • Nutrient recovery from deammonification effluent in a pilot study using two-step reject water treatment technology
    • Agnieszka Tuszyńska
    • Krzysztof Czerwionka
    2021 Full text Water Resources and Industry

    The aim of this study was to assess the possibility of phosphorus and nitrogen recovery from the liquid fraction of digestates (reject water) pilot study using a two-step technology, where the precipitation of biogenic compounds in the form of magnesium ammonium phosphate (struvite) will be preceded by a deammonification process. The tests confirmed the possibility of nutrient recovery from deammonification effluent. A removal efficiency from 85.0 to 92.0% of PO4 3− ions and from 13.0 to 21.0% of NH4 + ions in the form of magnesium salt was achieved, at a pH in the range of 8.7–9.0. However, when the pH value was from 9.1 to 9.3, phosphate ions were precipitated not only as magnesium salts, but also as calcium salts. The maximum struvite crystal sizes ranged from 0.72 to 1.65 mm, and was determined by the concentration of the suspended solids in the reject water, whose presence was a factor limiting the crystallization of struvite.

  • O (bez)skuteczności prawa polskiego wobec antropogenicznych zanieczyszczeń światłem sztucznym (ang. man-made light pollution)
    • Katarzyna Szlachetko
    • Karolina Zielińska-Dąbkowska
    2021 PRZEGLĄD PRAWA PUBLICZNEGO

    Przepisy obowiązującego prawa polskiego nie przewidują skutecznej regulacji w zakresie przeciwdziałania antropogenicznym zanieczyszczeniom światła sztucznego. Określone zjawisko nie jest kwalifikowane do „zanieczyszczeń”, o których mowa w ustawie - Prawo ochrony środowiska, zaś „emisja sztucznego światła” nie mieści się w pojęciu „emisji” uregulowanym w tej ustawie. Zważywszy na negatywne skutki zanieczyszczeń światłem sztucznym na życie i zdrowie człowieka, prawidłowy rozwój fauny i flory, naturalny nocny krajobraz, a także bezpieczeństwo ruchu drogowego – konieczne jest podjęcie działań legislacyjnych, które umożliwią przeciwdziałanie nadmiernej i szkodliwej emisji sztucznego światła. Niezbędne jest prawne zdefiniowanie nowej kategorii zanieczyszczeń wraz ze wskazaniem ich źródeł oraz ustanowieniem ograniczeń w przepisach prawa dotyczących ochrony środowiska. Poza tym skuteczność przeciwdziałania negatywnej emisji światła sztucznego jest bezpośrednio uzależniona od właściwej polityki i prawa planowania i zagospodarowania przestrzennego, a także od ustanowienia adekwatnych dla poszczególnych źródeł światła warunków technicznych w prawie budowlanym.

  • O imionach bogów
    • Przemysław Parszutowicz
    2021

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    • Beata Krawczyk-Bryłka
    • Krzysztof Nowicki
    2021 Full text Pismo PG

    Artykuł dotyczy neutralności sieci, która omówiona jest w kontekście zablokowania kont prezydenta USA w mediach społecznościowych. Odnosząc się do różnych znaczeń neutralności i opinii zebranych wśród informatyków, autorzy sformułowali rekomendacje dotyczące miejsca neutralności w edukacji informatycznej studentów.

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    • Piotr Samól
    2021

    Rozdział dotyczy prowadzonych prac restauracyjnych, konserwatorskich, archeologicznych i badań architektonicznych w kościele św. Mikołaja w ciągu ostatnich 200 lat i ich wypływu na rozwój wiedzy o historii budowlanej budynku. Autor odnosi się także do najnowszych prowadzonych przez siebie badań terenowych w kościele z lat 2018-2021. Praca stanowi zapowiedź monografii o architekturze kościołów dominikańskich.

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    • Krzysztof Nowicki
    2021 Full text Pismo PG

    W artykule podano przykłady usług internetowych o bardzo niskiej jakości. Wykazano, iż ogromny wpływ na jakość realizacji usług ma ciągłe wykorzystywanie w Internecie rozwiązań sprzed kilkudziesięciu lat. Pokazano jak budowa Internetu wpływa na opóźnienia przekazywania danych, oraz jak utrzymywanie zasady kompatybilności wstecznej uniemożliwia skokową poprawę jakości.