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Interaction of low energy electrons with formic acid monomer, dimer and trimer
PublicationConfigurations of the formic acid monomer, dimer and trimer are presented. We have calculated the total energies for these structures. We have considered also the negatively charged clusters and discussed the possible pathways of interaction of low energy electrons with monomers and clusters. Calculations have been executed using 6-311G** and 6-311++G** basis sets. The electron affinities of monomer and clusters are presented....
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Shaping of the turnout diverging track with variable curvature sections
PublicationThe paper presents an analytical method of shaping the turnout diverging railroad track with variable curvature segments on its length, which in an evident way distinguished it from a typical solution, made up of a single circular arc with no transition curves. Two separate causes including a linear and a nonlinear curvature one in the form of a polynomial have been examined. The obtained solutions of the problem have a universal...
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FPGA computation of magnitude of complex numbers using modified CORDIC algorithm
PublicationIn this work we present computation of the magnitude of complex numbers using a modified version of the CORDIC algorithm that uses only five iterations. The relationship between the computation error and the number of CORDIC iterations are presented for floating-point and integer arithmetics. The proposed modification of CORDIC for integer arithmetic relies upon the introduction of correction once basic computations are performed...
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The study of acoustic climate of the Southern Baltic
PublicationThis paper presents the statistical characteristics of seawater properties, which are necessary for predicting the propagation of acoustic waves in selected areas of the Baltic Sea. The statistics were elaborated based on long-term measurements of vertical distributions of sound speed, temperature, and salinity, and the nonlinearity parameter B/A. Nonlinear properties of the environment are considered, in connection...
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Searching for Critical Conditions During Lifeboat Launching – Simulations
PublicationThe article describes numerical simulations of the process of lifeboat launching at the ship’s side. The research is aimed at finding the values of ship motion parameters which appear to be most dangerous for people in the lowered lifeboat due to the generated accelerations. The simplified model of ship hull motion adopted at this research stage bases on a superposition of harmonic motions with given amplitudes and periods in six...
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Identification of Bodner-Partom Viscoplastic Model Parameters for Some Aluminum Alloys at Elevated Temperature
PublicationThe paper presents the identification process of inelastic (viscoplastic) properties for two aluminum alloys at a temperature of 120°C. The material parameters are calculated on the basis of uniaxial tension tests. Twelve tests at elevated temperature for each alloy have been performed—three tests for four different strain rates. The main purpose of the paper is to identify the Bodner-Partom viscoplastic model parameters for two...
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Monitoring of current collectors on the railway line
PublicationProper cooperation the current collectors and the overhead line is a pre-requisite for reliable and safe operation of railway transport. Instances of maladjustment and, in some cases, damage to the current collectors, occur between periodic inspections of the rolling stock. In order to detect such anomalies quickly, the test stand was developed, with the aim of monitoring the technical state of the current collectors under operating...
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Annihilation rates of low-energy positron scattering from simple diatomic molecules
PublicationWe discuss the calculations of Zeff coefficients for a series of diatomic molecules over the range of energies below the positronium formation. During the development of a general code for polyatomic, nonlinear molecules colliding with positrons, it was discovered that the earlier one, employed only for diatomic molecules, had an error. The error is corrected and the corrected results are presented here. We also discuss a way of...
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Comparison of natural frequencies of a circular saw blade obtained empirically and with FEM
PublicationThe knowledge of the natural frequencies’ values of circular saw blades is necessary to determine the minimal critical rotational speed in which they can work with required stability. Moreover, testing the circular saw blades with more complicated shapes, e.g. which have additional holes inside blades for cleaning knifes or additional indirect teeth in gullets, reveals some kind of problematic properties of these saw blades. The...
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Diagnosis of bearing damage in induction motors by instantaneous power analysis
PublicationResearch of the machine with simulated bearing damages has been carried out, where variable load torque, simulating bearing damage, was introduced. The results show that components which can be used for bearings diagnosis appear in the spectrum of the product of current and supply voltage instantaneous values. These components are easier to identify than the components of current spectrum, which have been used so far in diagnostic...
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Retrieval of Heterogeneus Sevices in C2NIWA Repository
PublicationThe paper reviews the methods used for retrieval of information and services. The selected approaches presented in the review inspired us to build retrieval mechanisms in a system for searching the resources stored in the C2NIWA repository. We describe the architecture of the system, its functions and the surrounding subsystems to which it is related. For retrieval of C2NIWA sevices we propos three approaches based on: keyword...
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An algorithmic approach to estimating the minimal number of periodic points for smooth self-maps of simply-connected manifolds
PublicationFor a given self-map f of M, a closed smooth connected and simply-connected manifold of dimension m 4, we provide an algorithm for estimating the values of the topological invariant D^m_r [f], which equals the minimal number of r-periodic points in the smooth homotopy class of f. Our results are based on the combinatorial scheme for computing D^m_r [f] introduced by G. Graff and J. Jezierski [J. Fixed Point Theory Appl. 13 (2013),...
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RECSYS CHALLENGE 2015: a BUY EVENT PREDICTION IN THE E-COMMERCE DOMAIN
PublicationIn this paper we present our approach to RecSys Challenge 2015. Given a set of e-commerce events, the task is to predict whether a user will buy something in the current session and, if yes, which of the item will be bought. We show that the data preparation and enrichment are very important in finding the solution for the challenge and that simple ideas and intuitions could lead to satisfactory results. We also show that simple...
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Improvement of time difference of arrival measurements resolution by using fractional delay filters in a direct sequence-code division multiple access radionavigation system
PublicationThis study presents a method of improving time measurements resolution in a direct sequence-code division multiple access receiver by using a fine code tracking loop based on fractional delay filtering of a despreading sequence. It briefly describes the structure of a generic digital code tracking loop and the proposed modification which allows to measure time difference of arrival values with the subsample resolution, together...
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Synthesis and biological evaluation of fluorinated 3-phenylcoumarin-7-O-sulfamate derivatives as steroid sulfatase inhibitors
PublicationIn the present work, we report the initial results of our study on a series of 3-phenylcoumarin sulfamate-based compounds containing C-F bonds as a novel inhibitors of steroid sulfatase (STS). The new compounds are potent STS inhibitors, possessing more than 10 times higher inhibitory potency than coumarin-7-O-sulfamate. In the course of our investigation, compounds 2b and 2c demonstrated the highest inhibitory effect in the enzymatic...
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New approaches to cutting resistance estimation of wood cutting process with circular-saw blades
PublicationTheoretical and experimental determination of values of cutting resistance belongs to the basic and simultaneously the most developed field of mechanics of this process. Energetic effects of wood sawing process are mainly calculated on the basis of the specific cutting resistance which, in wood cutting, is a function on a lot of factors. In this paper new method for calculation of cutting resistance is described. The latter method...
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Human-computer interactions in speech therapy using a blowing interface
PublicationIn this paper we present a new human-computer interface for the quantitative measurement of blowing activities. The interface can measure the air flow and air pressure during the blowing activity. The measured values are stored and used to control the state of the graphical objects in the graphical user interface. In speech therapy children will find easier to play attractive therapeutic games than to perform repetitive and tedious,...
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The decay of quantum correlations between quantum dot spin qubits and the characteristics of its magnetic-field dependence
PublicationWe address the question of the role of quantum correlations beyond entanglement in the context of quantum magnetometry. We study the evolution of the rescaled variant of the geometric quantum discord of two electron-spin qubits interacting with an environment of nuclear spins via the hyperfine interaction. We have found that quantum correlations display a strong magnetic-field sensitivity which can be utilized for decoherence-driven...
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Noise emitted by SKM Trains in Gdansk
PublicationHigh intensity traffic of SKM trains in Gdansk carries a significant level of noise emission. SKM line runs through the central part of the city and therefore in the vicinity of residential areas and recreational facilities. This research was planned and performed to find out what was the real noise emission of SKM trains and to determine whether the measurement noise values are within allowed limits. Individual acoustic events...
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Implementation of the Boundary Element Method to Two-Dimensional Heat Transfer with Thermal Bridge Effects
PublicationThe work presents an application of the boundary element method applied to a two-dimensional conductive heat transfer. The algorithm of the method is explained and its advantages are outlined. Green's function as a fundamental solution for Poisson's equation in two dimensions was used and the direct approach was applied. The presented results concern building construction elements as typical cases of thermal bridges. Some properties...
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Determination of Pesticide Residues in Honey using the GC×GC-TOFMS Technique
PublicationIn this study, a QuEChERS method and gas chromatography coupled with time-of-flight mass spectrometry (GCxGC-TOFMS) was developed for rapid extraction and simultaneous determination of 12 pesticide residues in honey. The GCxGC-TOFMS method was validated according to the SANCO guidance in terms of linearity, selectivity, reproducibility and recovery. Regarding the results, recovery rates ranged between 70-120% with relative standard...
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Determination of time delay between ventricles contraction using impedance measurements
PublicationThe paper presents a novel approach to assessment of ventricular dyssynchrony basing on multichannel electrical impedance measurements. Using a proper placement of electrodes, the sensitivity approach allows estimating time difference between chambers contraction from over determined nonlinear system of equations. The theoretical considerations which include Finite Element Method simulations were verified using measurements on...
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Calculation of an ultimate load value of a silo with geometric imperfections in the shape of eigenforms
PublicationThe ultimate load value of a silo with initial geometric imperfections was measured. The structure was loaded with wind. Imperfections were assumed as translations of the shell nodes from perfect geometry taken from eigenforms and their combinations. Two variants of the maximum deflection placement with respect to the direction of wind pressure were proposed. The first consists in applying the maximum wind pressure to the element...
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On the differential effect of temperature on the Nusselt-Rayleigh relationship in free convection
PublicationThe aim of and inspiration behind this paper was to explain the reasons, also observed by other researchers, of the discrepancy in the results of experimental free convection, which for small Rayleigh and Nusselt numbers in the initial phase of research can sometimes reach several hundred percent. These discrepancies decrease with increasing heating power and plate surface temperature, in proportion to the increase in Ra and Nu,...
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Wykorzystanie metody Neldera-Meada do identyfikacji wartości parametrów niequasi-statycznego modelu małosygnałowego tranzystora MOS
PublicationW artykule zaprezentowano wyniki zastosowania metody sympleksu Neldera-Meada do ekstrakcji wartości parametrów niequasi-stycznego modelu małosygnałowego tranzystora MOS. Przedstawiono równoważny elektryczny schemat zastępczy i model matematyczny nowego modelu małosygnałowego MOSFETa dla częstotliwości mikrofalowych. Opisano zaimplementowany algorytm i otrzymane rezultaty badań.
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Nitrogen removal in vertical flow constructed wetlands: influence of bed depth and high nitrogen loadings
PublicationThe aim of the study was to evaluate the nitrogen removal and its effects on the plant’s growth and leaves morphology. using two subsurface vertical flow (VF bed), with different depths (0.24 m2 × 0.70 m; 0.24 m2 × 0.35 m) and nitrogen load increments. The VF bed were planted with Vetiveria zizanioides, filled with light expanded clay aggregates (Leca®NR 10/20) and fed in parallel mode with synthetic wastewater. High ammonium nitrogen...
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Stabilities of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, and their derivatives under controlled conditions analyzed using liquid chromatography coupled with tandem mass spectrometry
PublicationBisphenol A diglycidyl ether (BADGE), bisphenol F diglycydyl ether (BFDGE), and their related compounds are widely used as precursors in production of epoxy resins. The high reactivity of these compounds makes the development of analytical methodologies that ensure appropriate metrological accuracy crucial. Consequently, we aimed to determine whether and to what extent the composition of the solution and storage conditions affect...
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Denitrifcation rate in the mainstream deammonification
PublicationThe conventional processes of biological nitrogen removal based on nitrification and denitrification does not fit properly into the concept of the circular economy. As the alternative one should consider the deammonification process, which is a combination of partial nitrification (nitritation) and Anammox processes. It consists of removing ammonium nitrogen from wastewater under anaerobic conditions by a group of autotrophic microorganisms....
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Investigating the Impact of Curing System on Structure-Property Relationship of Natural Rubber Modified with Brewery By-Product and Ground Tire Rubber
PublicationThe application of wastes as a filler/reinforcement phase in polymers is a new strategy to modify the performance properties and reduce the price of biocomposites. The use of these fillers, coming from agricultural waste (cellulose/lignocellulose-based fillers) and waste rubbers, constitutes a method for the management of post-consumer waste. In this paper, highly-filled biocomposites based on natural rubber (NR) and ground tire...
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An ANN-Based Approach for Prediction of Sufficient Seismic Gap between Adjacent Buildings Prone to Earthquake-Induced Pounding
PublicationEarthquake-induced structural pounding may cause major damages to structures, and therefore it should be prevented. This study is focused on using an artificial neural network (ANN) method to determine the sufficient seismic gap in order to avoid collisions between two adjacent buildings during seismic excitations. Six lumped mass models of structures with a different number of stories (from one to six) have been considered in...
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Conjugates of Ciprofloxacin and Levofloxacin with Cell-Penetrating Peptide Exhibit Antifungal Activity and Mammalian Cytotoxicity
PublicationSeven conjugates composed of well-known fluoroquinolone antibacterial agents, ciprofloxacin (CIP) or levofloxacin (LVX), and a cell-penetrating peptide transportan 10 (TP10-NH2) were synthesised. The drugs were covalently bound to the peptide via an amide bond, methylenecarbonyl moiety, or a disulfide bridge. Conjugation of fluoroquinolones to TP10-NH2 resulted in congeners demonstrating antifungal in vitro activity against human...
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Bee Bread Exhibits Higher Antimicrobial Potential Compared to Bee Pollen
PublicationThis study aimed at investigation of the antimicrobial potential of ethanolic extracts of bee bread (BB) and bee pollen (BP) and suspensions of these products in MHB (Mueller Hinton Broth). We covered 30 samples of BP and 19 samples of BB harvested in Polish apiaries. Slightly lower activity was observed against Gram-negative bacteria compared to Gram-positive staphylococci. BB extracts exhibited higher inhibitory potential with...
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Determination of Vehicles Load Equivalency Factors for Polish Catalogue of Typical Flexible and Semi-rigid Pavement Structures
PublicationThe new Polish Catalog of Typical Flexible and Semi-rigid Pavement Structures was introduced to use in practice in 2014. Much of works were focused on actualization of vehicles load equivalency factors. For this purpose data delivered from weigh-inmotion were analyzed. Four methods of determination of load equivalency factors for pavement structure design were compared. The analysis showed that fourth power equation, AASHTO 1993...
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Concrete versus green corridors in road planning. Gdansk case
PublicationThe aim of an article is to present the threats which may be caused by the construction of the transit road inside the city structure, and some mitigation measures aiming to eliminate or minimize environmental and landscape damages and social problems. Theoretical guidelines and conclusions will be followed by the example illustrating the problem. As an answer, some guidelines enabling sustainable road planning will be presented....
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Synthesis and biological evaluation of fluorinated N-benzoyl and N-phenylacetoyl derivatives of 3-(4-aminophenyl)-coumarin-7-O-sulfamate as steroid sulfatase inhibitors
PublicationIn the present work, we report convenient methods for the synthesis of 3-(4-aminophenyl)-coumarin-7-O-sulfamate derivatives N-acylated with fluorinated analogues of benzoic or phenylacetic acid as steroid sulfatase (STS) inhibitors. The design of these potential STS inhibitors was supported by molecular modeling techniques. Additionally, computational docking methods were used to determine the binding modes of the synthesized inhibitors...
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ADAPTATION OF THE ACTIVATED SLUDGE TO THE DIGESTATE LIQUORS DURING THE NITRIFICATION AND DENITRIFICATION PROCESSES
PublicationThe activated sludge process of the digestate liquors after chemical separation was conducted using a 10 L lab-scale sequencing batch reactor (SBR) and a 0.50 m3 pilotscale SBR independently (with pH control). Due to the relatively high concentration of free ammonia (FA), clear inhibitory effects of the digestate liquors on the nitrifying bacteria were observed. The adaptation of the activated sludge to the toxicity was evaluated...
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Stormwater runoff in the urbanized coastal basin of Gdańsk Urbanized basin of Gdańsk
PublicationAnthropopressure strongly affects the primal water cycle. Alternation of the natural basins imposes changes of drainage patterns, reduction of bioretention, infiltration and base flow. As a result the overland flow predominates and greater runoff rates flow into storm water collection systems and reservoirs. Moreover changing climatic conditions increase the frequency of rapid extreme weather events. Infrastructures of urban areas...
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The effect of high pressure and sub-zero temperature on total antioxidant capacity and the content of vitamin C, fatty acids and secondary products of lipid oxidation in human milk
PublicationThe objective of this study was to compare of the effects of high pressure of 193 MPa at - 20°C and Low Temperature Long Time pasteurization (LTLT or holder pasteurization, 62,5°C; 30 min) on the content and composition of fatty acids (FAs), concentrations of secondary products of lipid oxidation (TBARS), the total antioxidant capacity (TAC), total vitamin C and ascorbic acid (AsA) content in human milk. It was shown that no significant...
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Game Theory Analysis of Bidding for a Construction Contract
PublicationThe authors are concerned with a bidding problem. There are two companies (P1 and P2) bidding for a highway construction project. In order to be more competitive, P1 considers buying a new gravel pit near the construction site. The basic cost of the pit is known to both companies. However, there is also an additional, hidden, cost (C) known only to P1. P2 is uncertain whether the hidden cost is C = 0 or C = x. P1 plans to bid for...
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RE-SHAPING THE LAND AND WATER CONNECTIONS AND ITS ROLE IN ACHIEVING LANDSCAPE AND ECOLOGICAL SYSTEMS’ CONTINUITY ON THE POST-INDUSTRIAL TERRITORIES
PublicationThis paper delves into recently applied strategies of creating new water areas and modifying the existing ones as a part of the transformation processes of post-industrial territories. It proves that while the pursuit for unique architectural and urban space values remains an important factor contributing to such modifications, they may also play an important role in reclaiming ecological systems continuity. On the basis of theoretical...
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Processing, mechanical and thermal behavior assessments of polycaprolactone/agricultural wastes biocomposites
PublicationIn this paper, brewer’s spent grain (BSG) was applied as potential lignocellulose biofiller in biocompos-ites based on polycaprolactone (PCL). The PCL/BSG biocomposites filled with varying content of biofillerswere prepared via low-temperature melt-compounding. These conditions allow limiting thermal degra-dation of used biofillers during processing. The influence of biofiller content (ranging from 25 to 200parts by weight on 100...
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Is It Right To Predict Cutting Forces On The Basis Of Wood Density?
PublicationSeveral properties of wood can be correlated to wood density. It is widely accepted that the cutting power requirements are following this general assumption. Therefore, according to classic literature sources available for determination of the cutting power for both band- and circular- sawing machines, the cutting power requirements (and/or cutting forces) are computed as a function of the wood specific gravity SG. It was shown...
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Seismic Response Analysis of Knee-Braced Steel Frames Using Ni-Ti Shape Memory Alloys (SMAs)
PublicationShape Memory Alloys (SMAs) are known as active materials that can be widely used for structural purposes due to their flag-shape behavior under loading and reloading. Their unique characteristics provided a potential solution for civil engi-neers especially to model buildings with the capability of dissipating seismic en-ergy. In this study, the main purpose is to explore the seismic behavior of Knee-Braced Frames (KBFs) and...
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Synthesis of Cyano-Benzylidene Xanthene Synthons Using a Diprotic Brønsted Acid Catalyst, and Their Application as Efficient Inhibitors of Aluminum Corrosion in Alkaline Solutions
PublicationNovel cyano-benzylidene xanthene derivatives were synthesized using one-pot and condensation reactions. A diprotic Brønsted acid (i.e., oxalic acid) was used as an effective catalyst for the promotion of the synthesis process of the new starting xanthene–aldehyde compound. Different xanthene concentrations (ca. 0.1–2.0 mM) were applied as corrosion inhibitors to control the alkaline uniform corrosion of aluminum. Measurements were...
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Determination of Odor Air Quality Index (OAQII) Using Gas Sensor Matrix
PublicationThis article presents a new way to determine odor nuisance based on the proposed odor air quality index (OAQII), using an instrumental method. This indicator relates the most important odor features, such as intensity, hedonic tone and odor concentration. The research was conducted at the compost screening yard of the municipal treatment plant in Central Poland, on which a self-constructed gas sensor array was placed. It consisted...
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Enhancing seismic performance of rigid and semi-rigid connections equipped with SMA bolts incorporating nonlinear soil-structure interaction
PublicationNowadays, using smart connections can improve the performance of buildings with some recentering features that are from the superelastic behavior of Shape Memory Alloys (SMAs). It seems that there is different rigidity between the designed connection and the real one in Steel Moment-Resisting Frames (SMRFs), which can be considered as a problematic issue due to the importance of connections in seismic performance assessment. This...
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Wpływ parametrów konstrukcyjnych sprzęgieł mokrych i ich sterowania na zmiany wybranych wielkości fizycznych w trakcie zmian przełożenia przekładni mechanicznej
PublicationPrzedmiotem rozprawy doktorskiej jest analiza wpływu parametrów konstrukcyjnych i sterowania sprzęgłami ciernymi na zmiany wybranych wielkości fizycznych w trakcie zmiany przełożenia dwubiegowej przekładni mechanicznej typu Powershift. W ramach rozprawy przedstawiono znane rozwiązania skrzyń biegów maszyn roboczych. Szczególną uwagę poświęcono skrzyniom Powershift i stosowanych w nich rozwiązaniach sterowania sprzęgłami. Ponadto...
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ARIMA vs LSTM on NASDAQ stock exchange data
PublicationThis study compares the results of two completely different models: statistical one (ARIMA) and deep learning one (LSTM) based on a chosen set of NASDAQ data. Both models are used to predict daily or monthly average prices of chosen companies listed on the NASDAQ stock exchange. Research shows which model performs better in terms of the chosen input data, parameters and number of features. The chosen models were compared using...
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Mechanical Properties and Residual Stress Measurements of Grade IV Titanium and Ti-6Al-4V and Ti-13Nb-13Zr Titanium Alloys after Laser Treatment
PublicationNowadays, surface engineering focuses on research into materials for medical applications. Titanium and its alloys are prominent, especially Ti-6Al-4V and Ti-13Nb-13Zr. Samples made of pure grade IV titanium and the titanium alloys Ti-6Al-4V and Ti-13Nb-13Zr were modified via laser treatment with laser beam frequency f = 25 Hz and laser beam power P = 1000 W during a laser pulse with duration t = 1 ms. Subsequently, to analyze...
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Sources and composition of chemical pollution in Maritime Antarctica (King George Island), part 1: Sediment and water analysis for PAH sources evaluation in the vicinity of Arctowski station
PublicationThe paper presents a study regarding the identification of polycyclic aromatic hydrocarbons (PAHs) in fresh waters and surface sediments on the western shore of Admiralty Bay over four sampling seasons from 2017 to 2018. The results were compared to literature data from 2016 to provide a more comprehensive image of the environmental fate of PAHs over the years. The highest value of Σ PAHs was 82.9 ng/L and 445 ng/g dw in water...