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Wyniki wyszukiwania dla: NON-LINEAR FEM ANALYSIS
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DETECTION OF DEBONDING IN STEEL BARS EMBEDDED IN CONCRETE USING GUIDED WAVE PROPAGATION
PublikacjaThe paper presents a non-destructive diagnostic technique based on guided wave propagation phenomenon used to assess the adhesive bonding between a steel bar and a concrete cover. Double-layered cylindrical specimens with different levels of debonding and its location were investigated. The influence of bonding length on the excitation of multiple modes of longitudinal guided waves was analysed. Numerical simulations of guided...
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Review of hydrogen production technologies for automotive sector – thermodynamic analysis of energy and exergy losses
PublikacjaFew recent years has shown that hydrogen technology has a good chance to replace petroleum technology in automotive sector. However, hydrogen in pure form practically does not occur on Earth. That is why H2 form is used only as an energy carrier and it must be produced using another source of energy form water or hydrocarbon fuels. In this paper short overview of hydrogen production technology has been presented, with energy and...
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Centralized and Distributed Structures of Intelligent Systems for Aided Design of Ship Automation
PublikacjaA design process and accepted solutions made during this process, often base on non-formalized knowledge, obtained from designer (expert) intuition and practice. There are no formalized rules assuring the correctness of design solutions. The analysis of design process of ship automation, including ship power system, shows that this process can be supported by application of the artificial intelligence elements. The article presents...
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Polarization-sensitive optical coherence tomography for ceramic materials inspection
PublikacjaCeramics production is looking for a fast, reliable and non-destructive method that can be implemented on site for defect detection and analysis. In this paper we present polarization-sensitive optical coherence tomography (PS-OCT) as a method for defect inspection. Proposed extensions to standard OCT provide additional information for complete characterization of tested object. We compare OCT and microscope imaging that can easily...
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Modelling of Objects Behaviour for Their Re-identification in Multi-camera Surveillance System Employing Particle Filters and Flow Graphs
PublikacjaAn extension of the re-identification method of modeling objects behavior in muti-camera surveillance systems, related to adding a particle filter to the decision-making algorithm is covered by the paper. A variety of tracking methods related to a single FOV (Field of Vision) are known, proven to be quite different for inter-camera tracking, especially in case of non-overlapping FOVs. The re-identification methods refer to the...
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Assessment of dynamic characteristics of thin cylindrical sandwich panels with magnetorheological core
PublikacjaBased on the equivalent single-layer linear theory for laminated shells, free and forced vibrations of thin cylindrical sandwich panels with magnetorheological core are studied. Five variants of available magnetorheological elastomers differing in their composition and physical properties are considered for smart viscoelastic core. Coupled differential equations in terms of displacements based on the generalized kinematic hypotheses...
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4-Point beam tensile test on a soft adhesive
PublikacjaAn adhesive butt joint with a soft bondline has been studied. A series of experiments was conducted on test pieces constituted of aluminium adherends bonded with a low modulus epoxy adhesive, ScotchWeld™ 2216. The joint was subjected to four point bending, in tension/compression loading, under constant deflection rate, with the bondline being parallel to the applied load. The objective was to examine and evaluate crack nucleation...
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Damage of a post-tensioned concrete bridge – Unwanted cracks of the girders
PublikacjaThe cracking of a post-tensioned T-beam superstructure, which was built using the incremental launching method, is analyzed in the paper. The problem is studied in detail, as specific damage was observed in the form of longitudinal cracks, especially in the mid-height zone of the girder at the interface of two assembly sections. The paper is a case study. A detailed inspection is done and non-destructive testing results of the...
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Nonlinear properties of the Gotland Deep – Baltic Sea
PublikacjaThe properties of the nonlinear phenomenon in water, including sea water, have been well known for many decades. The feature of the non homogeneous distribution of the speed of sound along the depth of the sea is very interesting from the physical and technical point of view. It is important especially in the observation of underwater area by means of acoustical method ( Grelowska et al ., 2013; 2014). The observation of the underwater...
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Surface sliding in human abdominal wall numerical models: Comparison of single-surface and multi-surface composites
PublikacjaDetermining mechanical properties of abdominal soft tissues requires a coupled experimental-numerical study, but first an appropriate numerical model needs to be built. Precise modeling of human abdominal wall mechanics is difficult because of its complicated multi-layer composition and large variation between specimens. There are several approaches concerning simplification of numerical models, but it is unclear how far one could...
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Local dynamics of fluids and dielectrics as the foundation of signal-carrying wave properties
PublikacjaThis paper develops an original approach to fundamental problems of classical linear acoustics and electromagnetics, proving a crucial role of doubly-dynamic local properties of a propagation medium in supporting wave-like fields able to carry information signals. The proof is composed of two steps concerning, subsequently, fluid acoustics and dielectric electromagnetics. The first step consists in complementing a common, practically...
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Effectiveness of Random Field Approach in Serviceability Limit State Analysis of Strip Foundation
PublikacjaThis work conducts a probabilistic inquiry on how the variability of the parameter defining soil deformability affects the settlement of the foundation located on the soil. The analysis addresses the random foundation model to relevantly estimate the probability of allowable deflection exceedance. The constitutive model parameter is based either on a single random variable or a random field. The computations incorporate direct...
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Proposal of New Tracer Concentration Model in Lung PCT Study Comparison with Commonly Used Gamma-variate Model
PublikacjaPerfusion computed tomography (pCT) is one of the methods that enable non-invasive imaging of the hemodynamics of organs and tissues. On the basis of pCT measurements, perfusion parameters such as blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface (PS) are calculated and then used for quantitative evaluation of the tissue condition. To calculate perfusion parameters it is necessary to approximate...
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Application of multivariate statistics in assessment of green analytical chemistry parameters of analytical methodologies
PublikacjaThe study offers a multivariate statistical analysis of a dataset, including the major metrological, “greenness” and methodological parameters of 43 analytical methodologies applied for aldrin determination (a frequently analyzed organic compound) in water samples. The variables (parameters) chosen were as follows: metrological (LOD, recovery, RSD), describing the “greenness” (amount of the solvent used, amount of waste generated)...
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The point estimate method in a reticulated shell reliability analysis
PublikacjaThe objective of this paper is to present an application of the point estimate method (PEM) that can determine the probabilistic moments for engineering structures. The method is reasonably robust and adequately accurate for a wide range of practical problems. It is a special case of numerical quadrature based on orthogonal polynomials. The main advantage of this method is that, unlike FORM or SORM, it is not necessary to carry...
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Simple smartphone-based methods for the determination of bioactive compounds in wine
PublikacjaA set of simple smartphone-based methods of bioactive compounds determination were developed for wine analysis. Procedures for smartphone-based determination of the total content of phenolic compounds, flavonoids, anthocyanins and biogenic amines, as well as measurement of antioxidant activity were developed and fully validated. The experimental setup is based on smartphone and 3D-printed device, though it is very simple and can...
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PHONEME DISTORTION IN PUBLIC ADDRESS SYSTEMS
PublikacjaThe quality of voice messages in speech reinforcement and public address systems is often poor. The sound engineering projects of such systems take care of sound intensity and possible reverberation phenomena in public space without, however, considering the influence of acoustic interference related to the number and distribution of loudspeakers. This paper presents the results of measurements and numerical simulations of the...
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Comparison of classical Winter's bracing requirements of compressedtruss chord with stability analysis of 3D truss-model
PublikacjaMost code requirements concerning bracing are based on principles developed by Winter. The present research is devoted tostudy a lateral buckling of truss with linear elastic side supports. The classical Winter's model of truss chord in the case ofout of the truss plane buckling is compared with nonlinear analysis of 3D truss model. Full bracing condition, that permitsthe truss chord to support load level corresponding to an unbraced...
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Thermal degradation kinetics of poly(propylene succinate) prepared with the use of natural origin monomers
PublikacjaLinear biobased polyester polyols were prepared with the use of succinic acid and 1,3-pro- panediol (both with natural origin). Tetraisopropyl orthotitanate (TPT) was used as a catalyst. In order to determine the effect of various synthesis temperature conditions on the thermal degradation kinet- ics, nine sequences of temperature conditions were used during two-step polycondensation reaction. Thermogravimetric analysis was conducted...
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The Current State-of-the-Art in the Determination of Pharmaceutical Residues in Environmental Matrices Using Hyphenated Techniques
PublikacjaSeveral thousand tons of pharmaceuticals and their transformation products (metabolites and degradation products) are introduced into the environment each year. They affect both human health and the environment, therefore, analytical procedures enabling the determination of a wide range of pharmaceuticals at trace levelswithminimal effort, time, and energy are required. Nowadays, hyphenated techniques are commonly applied in pharmaceutical...
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The analysis of the determination of points positions using photogrammetric methods
PublikacjaThis article was created as a result of research conducted within the master thesis. The purpose of the research was to analyze the accuracy of determining the actual position of the photographed points according to the calculated parameters. The accuracy of photos alignment was determined as parameters, which determine their external and internal orientation. In order to determine the location of the determined points, it was...
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Towards Synthetic and Balanced Digital Government Benchmarking
PublikacjaReliable benchmarking is essential for effective management of the government digitalization efforts. Existing benchmarking instruments generally fail to support this target. One problem is the diversity of instruments, resulting in a split image of digital progress and adding ambiguity to policy decisions. Another problem is disconnect in assessing progress between digital and traditional “analog” governance, lending support to...
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Monitoring Steel Bolted Joints during a Monotonic Tensile Test Using Linear and Nonlinear Lamb Wave Methods: A Feasibility Study
PublikacjaThe structural integrity of steel bolted joints may be compromised due to excessive loading. Therefore, condition assessment and the detection of potential defects before they cause a failure have become a major issue. The paper is focused on the condition monitoring of a bolted lap joint subjected to progressive degradation in a tensile test. The inspection used Lamb waves propagated through the overlap area. Wave propagation...
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Determination of the optimal curvature of the turnout diverging track for HSR using dynamic analysis
PublikacjaThe paper presents an analytical method of identifying the curvature of the turnout diverging track consisting of sections of varying curvature. Such turnout is mainly applied on High Speed Railway. Both linear and nonlinear (polynomial) curvatures of the turnout diverging track are considered in the paper. Obtained solutions enable to assume curvature values at the beginning and end point of the geometrical layout of the turnout.The...
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Nonreciprocal cavities and the time-bandwidth limit: comment
PublikacjaIn their paper in Optica 6, 104 (2019), Mann et al. claim that linear, time-invariant nonreciprocal structures cannot overcome the time-bandwidth limit and do not exhibit an advantage over their reciprocal counterparts, specifically with regard to their time-bandwidth performance. In this Comment, we argue that these conclusions are unfounded. On the basis of both rigorous full-wave simulations and insightful physical justifications,...
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Minimal number of periodic points for smooth self-maps of simply-connected manifolds
Dane BadawczeThe problem of finding the minimal number of periodic points in a given class of self-maps of a space is one of the central questions in periodic point theory. We consider a closed smooth connected and simply-connected manifold of dimension at least 4 and its self-map f. The topological invariant D_r[f] is equal to the minimal number of r-periodic points...
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Simulations of flows in the coastal zone of the Baltic Sea
Dane BadawczeThe study area is located in the Southern Baltic, within Polish Marine Areas, adjacent to the coastline in the vicinity of Lubiatowo village, where The Coastal Research Station (CRS) – a field laboratory of the Institute of Hydro-Engineering of the Polish Academy of Sciences (IBW PAN) –is situated. The numerical reconstruction of the coastal flow was...
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Hyperbolic heat conduction at a microscopic sliding contact with account of adhesion-deformational heat generation and wear
PublikacjaDifferent non-Fourier models were proposed to simulate temperatures in materials subjected to extremely fast thermal disturbances, when the speed of heat propagation should be concerned. The present study investigated temperature and heat balance at a microscopic sliding contact during a single frictional interaction based on the Cattaneo-Vernotte hyperbolic heat conduction equation. Two fundamental features of friction, namely,...
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Non-Perfect Propagation of Information to a Noisy Environment with Self-Evolution
PublikacjaWe study the non-perfect propagation of information for evolving a low-dimensional environment that includes self-evolution as well as noisy initial states and analyse the interrelations between the degree of objectivization and environment parameters. In particular, we consider an analytical model of three interacting qubits and derive its objectivity parameters. The numerical analysis shows that the quality of the spectrum broadcast...
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Rotor flux and EEMF observer for interior permanent magnet synchronous machine
PublikacjaIn recent years, the use of the interior permanent magnet synchronous machine (IPMSM) in various applications has grown significantly due to numerous benefits. Sensors are used to achieve high efficiency and good dynamic response in IPMSM drives but due to their high cost and reduced overall size of the system, sensorless control techniques are preferred. Non-sinusoidal distribution of rotor flux and slot harmonics are present...
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Właściwości złączy różnoimiennych stopu niklu Incoloy 800H ze stalą odporną na korozję 316L
PublikacjaW artykule przedstawiono problemy związane z wykonywaniem połączeń różnoimiennych typu Incoloy 800HT – austenityczna stal odporna na korozję 316L. Wykonano badania nieniszczące oraz niszczące, których wyniki pozwoliły na weryfikacje jakości wykonanych złączy próbnych. Nie stwierdzono występowania niezgodności spawalniczych oraz uzyskano wysokie właściwości wytrzymałościowe złączy. Badania metalograficzne ujawniły poprawne struktury...
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Theory and application of Near-infrared spectroscopy
PublikacjaIn recent years one can observe a significant increase in the requirements on quality control in all industrial sectors. The growing number of involved analyses makes the traditional, time consuming, requiring use of large quantities of reagents, thus expansive methods inconvenient especially for industrial applications. Fortunately, there is a very fast, cheap and not invasive analytical method that is increasingly used in qualitative...
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Advanced Scalar-valued Intensity Measures for Residual Drift Prediction of SMRFs with Fluid Viscous Dampers
PublikacjaMaximum Residual Inter-story Drift Ratio (RIDRmax) plays an important role to specify the state of a structure after severe earthquake and the possibility of repairing the structure. Therefore, it is necessary to predict the RIDRmax of Steel Moment-Resisting Frames (SMRFs) with high reliability by employing powerful Intensity Measures (IMs). This study investigates the efficiency and sufficiency of scalar-valued IMs for predicting...
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Process layout planning and optimised product range selection in manufacture of wooden construction sets
PublikacjaThis paper introduces a systematic deterministic framework for planning and the analysis of facility layouts aimed at manufacturing a variety of parts, as components of specific end products. The essence of the proposed approach lies in the decomposition of a traditional job-shop into layout modules of generic material flow patterns, that inherently yields improved efficiency of the entire system. It entails the use of a relevant...
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Kinetics of cross-linking processes of fast-curing polyurethane system
PublikacjaThis work focuses on the application of thermal analysis and kinetics investigations to analyze chemical processes during cross-linking of the complex fast-curing polyurethane system. Non-isothermal Differential Scanning Calorimetry (DSC) measurements were performed for both stoichiometric mixtures of polyol and isocyanate component and for mixture with large isocyanate excess. Isoconversional methods were used to calculate initial...
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Thermoplastic polyurethane/(organically modified montmorillonite) nanocomposites produced by in situ polymerization
PublikacjaA series of polyurethane nanocomposites were synthesized from thermoplastic polyurethanes (with different hard segment ratios) and two types of organically modified montmorillonites (OMMT) - Cloisite® 10A and Cloisite® 20A. The thermal behavior was examined by non-isothermal thermogravimetry (TG, DTG), Differential Scanning Calorimetry (DSC) and Dynamic-Mechanical Thermal Analysis (DMTA). The results of X-ray analyses showed that...
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Diagnostics of commutation unit in satellite pumps and motors
PublikacjaThe article describes a part of the research on the development of satellite pumps and motors, conducted on Gdansk University of Technology as a part of grant "New elaborate of hydraulic satellite machines for drives with vegetable liquids and non-flammable liquids" (LIDER/35/102/L-2/10/NCBiR/2011) funded by the National Centre for Research and Development in Poland. The presented area includes the diagnostics of commutation units...
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The use of HPLC-Q-TOF-MS for comprehensive screening of drugs and psychoactive substances in hair samples and several “legal highs” products
PublikacjaNon-targeted screening of drugs present in herbal products, known as “legal high” drugs and in hair as a biological matrix commonly used in toxicological investigations was accomplished with the use of high pressure liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS). In total, 25 and 14 therapeutical drugs and psychoactive substances/metabolites were detected in investigated hair samples...
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A detector of sleep disorders for using at home
PublikacjaObstructive sleep apnea usually requires all-ni ght examination in a specialized clinic, under the supervision of a medical staff. Because of those requirements it is an expensive and a non-widely utilized test. Moving the examination procedure to patients’ home with automatic analysis algorithms involved will decrease the costs and make it available for larger group of patients. The developed device allows all-night recordings...
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Diagnostics of commutation unit in satellite pumps and motors
PublikacjaThe article describes a part of the research on the development of satellite pumps and motors, conducted on Gdansk University of Technology as a part of grant "New elaborate of hydraulic satellite machines for drives with vegetable liquids and non-flammable liquids" (LIDER/35/102/L-2/10/NCBiR/2011) funded by the National Centre for Research and Development in Poland. The presented area includes the diagnostics of commutation units...
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Speed Observer Structure of Induction Machine Based on Sliding Super-Twisting and Backstepping Techniques
PublikacjaThis paper presents an analysis of the two speed observer structures which are based on the backstepping and sliding super twisting approach. The observer stabilizing functions result from the Lyapunov theorem. To obtain the observer tuning gains the observer structure is linearized near the equilibrium point. The rotor angular speed is obtained from non-adaptive dependence. In the sensorless control system structure the classical...
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Jacek Namieśnik prof. dr hab. inż.
OsobyUrodził się 10 grudnia 1949 r. w Mogilnie, zmarł 14 kwietnia 2019 r. w Gdańsku – polski chemik, profesor nauk chemicznych, specjalizujący się w chemii analitycznej i środowiskowej. Rektor Politechniki Gdańskiej w latach 2016–2019. Studia wyższe ukończył w 1972 r. na Wydziale Chemicznym Politechniki Gdańskiej, uzyskując tytuł magistra inżyniera chemika. W 1972 r. rozpoczął pracę na Politechnice Gdańskiej, gdzie w 1978 r. obronił...
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In situ study of a composition of outlet gases from biogas fuelled Solid Oxide Fuel Cell performed by the Fourier Transform Infrared Spectroscopy
PublikacjaThe purpose of this study was to develop a method and software based on the Fourier Transform Infrared Spectroscopy for the in-situ, quantitative analysis of the composition of outlet gases from Solid Oxide Fuel Cell (SOFC). The calibration procedure performed at the beginning of the experiment indicated a polynomial dependence between the concentration of a calibrating gas (CO, CO2, CH4) and the corresponding integrated absorbance in...
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Ruch wirowy wywoływany przez ultradźwięk w płynach z relaksacją
PublikacjaRozprawa doktorska poświęcona jest badaniu ruchu wirowego wywoływanego przez ultradźwięk w różnych modelach płynów z relaksacją. Ma ona charakter teoretyczny, jednak wykorzystanie uzyskanych dzięki niej wyników może przynieść lepsze zrozumienie ruchu wirowego wywoływanego przez siłę akustyczną. W I rozdziale rozprawy przedstawione zostały ogólne rozważania dotyczące akustyki nieliniowej. Rozdział II dotyczy ruchu wirowego wywoływanego...
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Characteristics of the Polarised Off-Body Channel in Indoor Environments
PublikacjaThis paper addresses the depolarisation effect in off-body Body Area Networks channels, based on measurements performed at 2.45 GHz in an indoor environment. Seven different scenarios, involving both static and dynamic users, were considered, taking a statistical perspective. The analysis of the cross-polarisation discrimination is performed, as well as the analysis of path loss in co- and cross-polarised channels. Results show...
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Characteristics of the polarised off-body channel in indoor environments
PublikacjaThis paper addresses the depolarisation effect in off-body body area networks channels, based on measurements performed at 2.45 GHz in an indoor environment. Seven different scenarios, involving both static and dynamic users, were considered, taking a statistical perspective. The analysis of the cross-polarisation discrimination is performed, as well as the analysis of path loss in co- and cross-polarised channels. Results show...
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Analysis of allophones based on audio signal recordings and parameterization
PublikacjaThe aim of this study is to develop an allophonic description of English plosive consonants based on recordings of 600 specially selected words. Allophonic variations addressed in the study may have two sources: positional and contextual. The former one depends on the syllabic or prosodic position in which a particular phoneme occurs. Contextual allophony is conditioned by the local phonetic environment. Co-articulation overlapping...
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Design analysis of ORC micro-turbines making use of thermal energy of oceans
PublikacjaThe article presents the results of the analysis of energy conversion cycles making use of thermal energy of oceans. The objects of analysis were two cases of closed Organic Rankine Cycle (ORC) power plants, which were: the cycle in which the vapour of the working medium was produced by warm oceanic water in the circum-equatorial zone, and the so-called “arctic” cycle in which this vapour was produced by non-frozen water in the circumpolar...
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Napawanie elementów wymiennika ciepła austenitycznym drutem proszkowym
PublikacjaNa potrzeby przemysłu energetycznego produkuje się wymienniki ciepła przeznaczone do eksploatacji w warunkach agresywnych chemicznie, np. w środowisku siarkowodoru. Z przyczyn ekonomicznych często stosuje się w takim przypadku materiały bimetaliczne wytwarzane procesami napawania. W artykule przedstawiono wyniki badań nieniszczących, pomiarów twardości, analizy składu chemicznego, pomiarów ferrytu delta oraz badań makro- i mikroskopowych...
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SZACOWANIE ZAWARTOŚCI BENZO(a)PIRENU W PYLE ZAWIESZONYM PM10 W AGLOMERACJI TRÓJMIEJSKIEJ ZA POMOCĄ WIELOWYMIAROWEJ REGRESJI LINIOWEJ=ESTIMATION OF BENZO(A)PYRENE CONTENT IN SUSPENDED DUST PM10 IN TRI-CITY AGGLOMERATION USING MULTIDIMENSIONAL LINEAR REGRESSION
PublikacjaW pracy przedstawiono próbę oszacowania przy pomocy wielowymiarowej regresji liniowej modelu empirycznego opisującego czynniki wpływające na zawartość B(a)P w pyle zawieszonym PM10 w Aglomeracji Trójmiejskiej w latach 2008-2011. Na przestrzeni tych lat średnioroczne stężenie B(a)P w PM10 wzrosło ponad dwukrotnie i ponad trzykrotnie przewyższa poziom docelowy. Z przeprowadzonych analiz wynika, że główną przyczyną wzrostu stężenia...