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Search results for: manuvering characteristic
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Reliable underwater communication system for shallow coastal waters
PublicationThis paper presents a reliable and robust low data rate spread spectrum approach which is implemented in the acoustic underwater communication system for shallow coastal waters. It shows operation assumptions of spread spectrum techniques based on the wellknown Shannon equation. It describes two methods of spread spectrum: frequency hopping spread spectrum and direct sequence spread spectrum; their block diagram and their characteristics...
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APPLICATION OF THE HIGH FREQUENCY LINEARIZATION OF THE EAR IN PATIENTS WITH TINNITUS . Metoda linearyzacji narządu słuchu u osób cierpiących z szumami usznymi
PublicationThis paper summarises the problem of tinnitus, hypotheses on its causes and the treatment methods. Moreover, a hypothesis on tinnitus origins is explained, based on the mechanisms of the analog-to-digital conversion and quantization. In addition, this paper describes methods of determining the acoustic intensity and spectra of low- level ultrasonic signals, as well as impedance characteristics of an ultrasound transducer. Furthermore,...
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Lax-Wendroff and McCormack Schemes for Numerical Simulation of Unsteady Gradually and Rapidly Varied Open Channel Flow
PublicationTwo explicit schemes of the finite difference method are presented and analyzed in the paper. The applicability of the Lax-Wendroff and McCormack schemes for modeling unsteady rapidly and gradually varied open channel flow is investigated. For simulation of the transcritical flow the original and improved McCormack scheme is used. The schemes are used for numerical solution of one dimensional Saint-Venant equations describing free...
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Personal adaptive tuning of mobile computer audio
PublicationAn integrated methodology for enhancing audio quality in mobile computers is presented. The key features are adaptation of the characteristics of the acoustic track to the changing conditions and to the user's individual preferences. Original signal processing algorithms are introduced, which concern: linearization of frequency response, dialogue intelligibility enhancement and dynamics processing tuned up to the user's preferences....
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About being entrepreneurial in challenging environments – theorizing on the social enterprise behavior in Poland
PublicationEntrepreneurial behaviors in challenging institutional environments have been widely investigated in the literature. One of the characteristics of these environments is resource scarcity. This is particularly valid in the context of social entrepreneurship. The aim of this paper is to identify entrepreneurial behaviors in social entrepreneurship and what is happening behind these processes in the context of transition country,...
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Periodic Properties of 1D FE Discrete Models in High Frequency Dynamics
PublicationFinite element discrete models of various engineering 1D structures may be considered as structures of certain periodic characteristics. The source of this periodicity comes from the discontinuity of stress/strain field between the elements. This behaviour remains unnoticeable, when low frequency dynamics of these structures is investigated. At high frequency regimes, however, its influence may be strong enough to dominate calculated...
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Particle Image Velocimetry Measurements of Airflow in Electrohydrodynamic Device for Dust Particle Collection
PublicationIn this paper the electrohydrodynamic (EHD)device for gas pumping and cleaning is presented. To induce an airflow in this EHD device corona discharge was used. The discharge was generated between the one-sided spike electrodes and the plate electrodes. An asymmetric electric field and generated discharge result in unidirectional gas flow through the EHD device. The current-voltage characteristics were measured and the corona discharge...
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Signatures and acoustic images of objects moving in water
PublicationObservation of underwater space is part of a generaltrend, which primary purpose is to protect and increasesafety in the selected area. The basic aim of the paper ispresentation of designated acoustic characteristics typicalfor objects moving on the water surface and under water,which represent some knowledge about detection of theseobjects. Create a catalog of acoustic signature and not onlyacoustic, as well as acoustic images...
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Experimentation, material modelling and simulation of bonded joints with a flexible adhesive
PublicationThe paper deals with material parameters identification of a flexible adhesive and the numerical simulation of its behaviour in a single lap bonded joint. The material modelling was based on the simple shear and tensile-shear laboratory tests of the bonded joints made of thin aluminium and polyurethane plates with the flexible adhesive Terostat MS 9360 manufactured by Henkel AG & Co. The adhesive was considered as a hyperelastic...
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EXPERIMENTAL AND NUMERICAL VALIDATION OF THE IMPROVED VORTEX METHOD APPLIED TO CP745 MARINE PROPELLER MODEL
PublicationThe article presents a numerical analysis of the CP745 marine propeller model by means of the improved vortex method and CFD simulations. Both numerical approaches are validated experimentally by comparing with open water characteristics of the propeller. The introduced modification of the vortex method couples the lifting surface approach for the propeller blades and the boundary element method for the hub. What is more, a...
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Review on the quality of sediments from the stormwater drainage system in the urban area
PublicationThe main task of the stormwater drainage system is a safe drainage of rainwater and snowmelt from the urban area to the receiver. The flow of rain water in the drainage pipes is directly related with the formation of sediments in the whole stormwater system. In addition, pollutants from land runoff get adsorbed to the sediments. The sludge is mainly formed in those elements of stormwater drainage system, wherein the flow conditions...
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The propagation of the waves in the CTO S.A. towing tank
PublicationThe paper presents the results of research focused on the wave propagation in the CTO S.A. deepwater towing tank. In the scope of paper, the wavemaker transfer function was determined for regular waves, based on the Biésel Transfer Function and further for irregular waves, based on Hasselman model of nonlinear energy transfer. The phenomena: wave damping, wave breakdown and wave reflection, were measured, analyzed and mathematically...
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Full Network Coverage Monitoring Solutions – The netBaltic System Case
PublicationThis paper defines the problem of monitoring a specific network, and more precisely – part of reporting process, which is responsible for the transport of data collected from network devices to station managers. The environment requires additional assumptions, as a specific network related to the netBaltic Project is to be monitored. Two new monitoring methods (EHBMPvU and EHBMPvF) are proposed, which priority is full network coverage....
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BIOVAC® WASTEWATER TREATMENT PLANTS IN THE MOUNTAIN NATIONAL PARKS.
PublicationThis paper presents characteristics of the Biovac® wastewater treatment plants operating in the mountain areas of the Polish national parks (NP): Tatrzanski NP and Babiogórski NP as well as in the West Spitsbergen NP. On the basis of the laboratory tests performed on raw sewage and the final effluent the efficiency of the wastewater treatment plants was evaluated. It was found that high COD values and rather high COD / BOD5 ratios...
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The hydration of selected biologically relevant molecules – the temperature effect on apparent molar volume and compression
PublicationThe densities and sound velocities at T = (288.15, 293.15, 298.15, 303.15 and 308.15) K were measured for aqueous solutions of glycine, trimethylamine-N-oxide, taurine and N-methylacetamide. From these data, the apparent molar volumes, V the apparent molar isentropic compressions, KS,, and the Passynski hydration numbers of solutes were determined. The concentration dependencies of the calculated quantities, their limiting values...
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The Brain of the city
PublicationIn order to highlight the characteristics of the West End of Wrocław, we conducted a site analysis. Using the strengths of the site, we were able to create a unique concept of the district while minimizing the impacts of weaknesses by design. The purpose of redesigning the West End of Wrocław is to attract new people to the district through the transformation of an identity. Initially, we conducted a SWOT analysis to identify the...
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DME as alternative fuel for compression ignition engines – a review
PublicationThe ecological issues and the depletion of crude oil, has led the researchers to seeking for non-petroleum based alternative fuels, along with more advanced combustion technologies, and after-treatment systems. The use of clean alternative fuels is the one of the most perspective method that aiming at resolving of the said issues. One of the promising alternative fuels that can be used as a clean highefficiency compression ignition...
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What Potential Entrepreneurs from Generation Y and Z Lack-IEO and the Role of EE
PublicationThis paper addresses the issue of individual entrepreneurship orientation (IEO) and entrepreneurship education (EE), which are both important for modern economic development. Intergenerational differences in these areas were discussed, especially characteristics of Generations Y and Z. The results of research conducted among 757 Polish students showing their IEO are presented. 80% of respondents displayed high levels of proactivity...
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Examining Feature Vector for Phoneme Recognition / Analiza parametrów w kontekście automatycznej klasyfikacji fonemów
PublicationThe aim of this paper is to analyze usability of descriptors coming from music information retrieval to the phoneme analysis. The case study presented consists in several steps. First, a short overview of parameters utilized in speech analysis is given. Then, a set of time and frequency domain-based parameters is selected and discussed in the context of stop consonant acoustical characteristics. A toolbox created for this purpose...
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The Application of Vibration Recording and Analysis in Tribological Research on Sliding Friction
PublicationThe paper reports on a tribological research on the macroscopic manifestation and characteristics of sliding friction. The aim of the task was to measure friction in lubricated sliding contacts and test the interactions between the environment (the test rig) and the experimental friction contact. Friction-induced vibrations were observed and studied as a manifestation of the process. The typical set of velocity and force/torque...
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Selected Aspects of Pavement Texture Influence on Tire Rolling Resistance
PublicationTire rolling resistance has a significant influence on fuel consumption in cars and trucks and on CO2 emissions. Rolling resistance depends on the tire construction, pavement texture and stiffness, as well as environmental and traffic conditions. This article presents a pilot study on the impact of pavement texture on the rolling resistance of passenger car tires. Reasons why Mean Profile Depth is not a good descriptor of pavement...
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Trust in Electronic Word-of-Mouth (eWOM): the concept and the most important determinants
PublicationeWOM and trust in it is now the most important factor in determining buyers' purchasing behavior. Familiarity with the determinants of trust establishes the formation of appropriate marketing activities. However, the growing number of new forms of eWOM and its increasingly complex and multidimensional nature have created a lot of confusion. The article aims to organize the concepts related to trust in eWOM, to indicate the most...
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Remote command and control capabilities for data acquisition systems provided by delay-tolerant network mechanisms
PublicationThe paper presents an assessment of a remote device reconfiguration service employing a Delay Tolerant Network (DTN) mechanisms. This service has been implemented as a part of a communication appliance dedicated to marine data transfer in off-shore and open sea areas. The service has been successfully deployed and validation test have been completed. The practical use-case has been defined as remote access to the equipment operating...
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Are deep eutectic solvents useful in chromatography? A short review
PublicationA literature update has been done concerning Deep Eutectic Solvents (DES) use in chromatography applications. The literature survey was based on the period from 2010 till 2020 and manuscripts reported in the data bases Web of Science and Scopus. The use of DES as mobile phase and mobile phase additives, stationary phases and solid phase modifiers and the use of DES as reaction solvents for chromatography use, were evaluated. Emphasis...
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Influence of Thermal Decomposition of Wood and Wood-Based Materials on the State of the Atmospheric Air. Emissions of Toxic Compounds and Greenhouse Gases
PublicationThis paper presents the energy characteristics of wood and wood-based materials in the form of commercially available pellets, furniture board (MDF) and OSB. Toxicometric indices were determined for gaseous destructs arising from thermal decomposition and combustion of the materials studied. The paper proves that combustion conditions are crucial in terms of toxic destructive emissions. It has been shown that the combustion of...
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A Set of Experience-Based Smart Synergy Security Mechanism in Internet of Vehicles
PublicationIn this article, we introduce a novel security mechanism, the Smart Synergy Security (3S). The mechanism uses the Set of Experience Knowledge Structure (SOEKS) and the synergy of security methods in different domains to provide the global optimal security strategy. The proposed strategy is taking into account the characteristics of information security (i.e. confidentiality, integrity, availability, controllability, and reviewability)...
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Conducted emi propagation modelling in the wound components.
PublicationThe modelling of EMC behaviour of power electronics converters require specific models of devices which are adequate in a wide frequency range. A novel equivalent-circuit model of the inductor, suitable for EMC applications, has been developed and validated. The model can be used for the analyses of wounded components' behaviour in the conducted-EMI frequency range. The parameters of the proposed model can be evaluated based on...
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The impact of material degradation on the resistance and reliability of truss structures
PublicationThe paper analyses limit load-carrying capacity and buckling load of truss towers used to support high voltage power lines. The analysed typical structure was subjected to characteristic loads and their combinations. The results were applied to assess structural resistance with regard to steel corrosion in the long-term operation. The extent of structural deterioration was assessed due to Young's modulus decrement in the course...
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Luminescence properties of Eu3+ and Tb3+ doped silica-based xerogels
PublicationPure SiO2 xerogels and SiO2 xerogels containing SrF2: Eu3+/: Tb3+ crystals were prepared using sol-gel method. Luminescent spectra showed excitation and emission peaks characteristic to Eu3+ and Tb3+ 4f - 4f transitions. ET Tb3+→Eu3+ has been observed. XRD pattern of SiO2 matrix confirmed lack of long range order. Patterns of SiO2-SrF2:Eu3+ and SiO2-SrF2:Tb3+ showed peaks corresponding to SrF2. SEM images have shown agglomerates...
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Reconstruction Methods for 3D Underwater Objects Using Point Cloud Data
PublicationExisting methods for visualizing underwater objects in three dimensions are usually based on displaying the imaged objects either as unorganised point sets or in the form of edges connecting the points in a trivial way. To allow the researcher to recognise more details and characteristic features of an investigated object, the visualization quality may be improved by transforming the unordered point clouds into higher order structures....
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Comparative molecular modelling of biologically active sterols
PublicationMembrane sterols are targets for a clinically important antifungal agent – amphotericin B. The relatively specific antifungal action of the drug is based on a stronger interaction of amphotericin B with fungal ergosterol than with mammalian cholesterol. Conformational space occupied by six sterols has been defined using the molecular dynamics method to establish if the conformational features correspond to the preferential interaction...
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Diagnosis of Damage in a Steel Tank Model by Shaking Table Harmonic Tests
PublicationThe aim of the present paper is to show the results of the shaking table experimental study concerning the diagnosis of damage in a model of cylindrical steel tank with self-supported roof which is filled with liquid. During the tests, the base of the structure was excited under the harmonic loading with variable frequency. The tests were repeated for different stages of damage, which was introduced in the model by easing the bolts...
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Domestic ORC micro-CHP combined with a commercial gas boiler
PublicationThe chapter presents the results of experimental studies conducted during the launch of the first in Poland demonstration prototype of the micro ORC coupled to a domestic gas boiler. The accomplished studies indicated the possibility for the ORC module to work with such boiler (autonomous source of heat) with a prototype single-stage axial micro turbine as the expansion machine. Confirmation of that fact has been delineated in...
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E-experiments in physics. Proper business process management, collaborative development process and project management guidance – remedy for avoiding the main IT project’s failure
PublicationOnly a few of learning aids and simulations of physical phenomena allow for building interactive experiments; experiments similar to those that should be conducted in physics laboratories at schools. Group of staff from Gdansk University of Technology decided to fill this market niche by designing and constructing a set of virtual experiments – so called e-experiments. To avoid common problems that a lot of IT products brought...
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Low-fidelity model considerations for simulation-based optimisation of miniaturised wideband antennas
PublicationHere, variable-fidelity electromagnetic (EM)-based design optimisation of miniaturised antennas is discussed. The authors focus on an appropriate selection of discretisation density of the low-fidelity EM model, which results in good performance of the optimisation algorithm in terms of its computational complexity and reliability. Trust-region gradient search with low-fidelity model corrected by means of non-linear frequency scaling...
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On low-fidelity models for variable-fidelity simulation-driven design optimization of compact wideband antennas
PublicationThe paper addresses simulation-driven design optimization of compact antennas involving variable-fidelity electromagnetic (EM) simulation models. Comprehensive investigations are carried out concerning selection of the coarse model discretization density. The effects of the low-fidelity model setup on the reliability and computational complexity of the optimization process are determined using a benchmark set of three ultra-wideband...
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Prospects in elongation of railway transition curves
PublicationThe paper presents an analysis of the elongation of transition curves in relation to railway track alignment correction and modernisation. The analysis is based on numerical computations for a wide range of parameters describing a typical railway geometrical layout with transition curves. The differences between the horizontal ordinates of the existing layout and the layout with the elongated transition curves are evaluated and...
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Fabrication and photoactivity of organic-inorganic systems based on titania nanotubes and PEDOT containing redox centres formed by different Prussian Blue analogues
PublicationHerein, the heterojunction composed of an inorganic substrate: ordered hydrogenated titania nanotubes (H-TiO2NTs) and a deposited organic film: poly(3,4-ethylenedioxythiophene) (PEDOT) is reported. The conducting polymer is modified with different transition metal haxacyanoferrates (Mehcf), wherein as metal: copper, iron, cobalt and nickel are introduced. The presence of various metal centres provides characteristic redox activity...
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The dynamic signature verification using population-based vertical partitioning
PublicationThe dynamic signature is an attribute used in behavioral biometrics for verifying the identity of an individual. This attribute, apart from the shape of the signature, also contains information about the dynamics of the signing process described by the signals which tend to change over time. It is possible to process those signals in order to obtain descriptors of the signature characteristic of an individual user. One of the methods...
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On Effective Bending Stiffness of a Laminate Nanoplate Considering Steigmann–Ogden Surface Elasticity
PublicationAs at the nanoscale the surface-to-volume ratio may be comparable with any characteristic length, while the material properties may essentially depend on surface/interface energy properties. In order to get effective material properties at the nanoscale, one can use various generalized models of continuum. In particular, within the framework of continuum mechanics, the surface elasticity is applied to the modelling of surface-related...
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TERMODYNAMIC CALCULATIONS OF TURBINE STEAM PARAMETERS
PublicationIn this work a heat balance was made for the nominal conditions of a block working with 18K370 turbine. For the parameters obtained, the thermal-flow calculations of the steam turbine were performed, maintaining the actual geometry of its flow system. Based on the nominal values obtained, iterative thermal and flow calculations were made for both the heat cycle of the power plant block and the steam turbine itself, seeking to obtain...
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Novel inorganic xerogels doped with CaWO 4 :xDy: Synthesis, characterization and luminescence properties
PublicationA series of novel phosphors based on silica xerogel doped with CaWO4:xDy(III) with various concentration of dysprosium ion was synthesized over a temperature of 800 C. The thermal analysis, XRD measurement and spectroscopic investigations of these materials are presented in this study. Steady state luminescence, luminescence excitation spectra as well as emission spectra have been measured. Under the ultraviolet light, the prepared...
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Does the low optical band gap of yellow Bi3YO6 guarantee the photocatalytical activity under visible light illumination?
PublicationBi3YO6, which is known as an ionic conductor, was tested here as an electrode and photoanode in contact with aqueous electrolytes. Bi3YO6 was deposited onto the Pt substrate and the such prepared electrode was polarized in various aqueous electrolytes. The optical energy band gap of the material equal to 1.89 eV was determined using the Kubelka-Munk function resulting from the UV-Vis spectrum (allowed indirect transition) and also...
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Performance of acicular grindable thermocouples for temperature measurements at sliding contacts
PublicationThe present study investigates the performance of acicular grindable thermocouples based on a constantan wire / steel hollow cylinder construction. The experiments showed that the measuring junction electrical resistance, temperature–voltage characteristic, measuring junction rise time and signal noise standard deviation of the acicular thermocouples are comparable to those of conventional J-type thermocouples with bare wire diameter...
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Fibrillar aggregates in powdered milk
PublicationThis research paper addresses the hypothesis that powdered milk may contain amyloid fibrils. Amyloids are fibrillar aggregates of proteins. Up to this time, research on the presence of amyloids in food products are scarce. To check the hypothesis we performed thioflavin T fluorescence assay, X-ray powder diffraction, atomic force microscopy and fluorescence microscopy imaging. Our preliminary results show that commercially available...
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Evolutionary Algorithm for Selecting Dynamic Signatures Partitioning Approach
PublicationIn the verification of identity, the aim is to increase effectiveness and reduce involvement of verified users. A good compromise between these issues is ensured by dynamic signature verification. The dynamic signature is represented by signals describing the position of the stylus in time. They can be used to determine the velocity or acceleration signal. Values of these signals can be analyzed, interpreted, selected, and compared....
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Excitation of Non-Wave Modes by Sound of Arbitrary Frequency in a Chemically Reacting Gas
PublicationThe nonlinear phenomena in the field of high intensity sound propagating in a gas with a chemical reaction, are considered. A chemical reaction of A → B type is followed by dispersion and attenuation of sound which may be atypical during irreversible thermodynamic processes under some conditions. The first and second order derivatives of heat produced in the chemical reaction evaluated at the equilibrium temperature, density and...
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Właściwości stali S460M napawanej pod wodą metodą lokalnej komory suchej
PublicationW artykule przedstawiono wyniki badań próbek ze stali S460M wykonanych pod wodą metodą lokalnej komory suchej. Pomiary twardości oraz analiza strukturalna wykazały, że dla określonych ilości wprowadzonego ciepła możliwe jest wykonanie złączy bez niezgodności spawalniczych. Stwierdzono formowanie się w pewnych warunkach pęknięć zimnych w SWC wywołanych procesami odprowadzania ciepła z materiału, które są charakterystyczne dla spawania...
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Niezgodność przekonań i działań menedżerów wobec pracowników w wieku 55+
PublicationArtykuł dotyczy problematyki postaw i działań menadżerów wobec pracowników w wieku 55+. W literaturze dotyczącej zarządzania wiekiem przytaczane są wyniki badań na temat cech charakteryzujących starszych pracowników. Porównuje się je czasami z cechami przypisywanymi pracownikom młodym. Cel prezentowanych w artykule badań sformułowany został nieco inaczej i dotyczył zweryfikowania zbieżności zalet przypisywanych starszym pracownikom...
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Metody analizy energochłonności w przemyśle
PublicationBadania przeprowadzone w rozprawie doktorskiej pokazują nową ideę analitycznych metod analizy energochłonności w zastosowaniu do dużych odbiorców przemysłowych. Jej skuteczności dowodzono na przykładzie wybranego obiektu przemysłu spożywczego. Metoda ta jest rozwinięciem dotychczasowych metod wskaźnikowych. Autorską nowością jest wykorzystanie charakterystyk energetycznych procesów technologicznych do wyznaczania referencyjnych...