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wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: PIEZOELECTRIC MAUTHORS FOCUS ON RESEARCH ARTICLES PUBLISHED IN THE LAST FIVE YEARS MOSTLY. THE PRIMARY SUBJECT OF THIS INVESTIGATION IS THE DEVELOPMENT OF PIEZOELECTRIC ULTRASONIC MOTORS INCLUDING OTOR
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Radar time budget optimization subject to angle accuracy constraint via cognitive approach
PublikacjaThe problem of minimizing dwell time in multifunction phased array radar is considered. Target of interest is assumed to fluctuate according to a generalization of Swerling family and the parameters of fluctuation model are assumed to be known. The a'priori position of the target is uncertain. Optimization, whose variables include pulse count and array transmit beampattern, is carried out subject to achieving a desired accuracy...
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University Students’ Research on Artificial Intelligence and Knowledge Management. A Review and Report of Multi-case Studies
PublikacjaLeading technologies are very attractive for students preparing their theses as the completion of their studies. Such an orientation of students connected with professional experiences seems to be a crucial motivator in the research in the management and business areas where these technologies condition the development of professional activities. The goal of the paper is the analysis of students’ thesis topics defended in the last...
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Sensorless five-phase induction motor drive with third harmonic injection and inverter output filter
PublikacjaThe paper presents a sensorless control approach for a five-phase induction motor drive with third harmonic injection and inverter output filter. In the case of the third harmonic injection being utilised in the control, the physical machine has to be divided into two virtual machines that are controlled separately and independently. The control system structure is presented in conjunction with speed and rotor flux observers that...
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Indeksy demokracji i stan zaawansowania ich rozwoju ze szczególnym uwzględnieniem projektu Varieties of Democracy - Democracy indices and their state of development with a special focus on the Varieties of Democracy project
PublikacjaIndeksy demokracji już od wielu lat pomagają naukowcom w klasyfikowaniu reżimów politycznych na całym świecie. Czy jednak projekty tego typu mierzyły i mierzą jakość demokracji w sposób adekwatny? Na podstawie przeglądu literatury przedmiotu można stwierdzić znaczny rozwój metodologii w tym zakresie od końca XX wieku w odpowiedzi na wcześniejsze braki.Autor artykułu opisuje rozwój indeksów demokracji od pierwszych...
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Resonant ultrasonic spectroscopy in high-voltage varistor spectroscopy
PublikacjaResonant spectroscopy is an effective non-destructive testing method focused on defects in tested objects. The testing procedure, based on the resonant pattern, allows rejection of the tested samples with defects which do not fit the pattern. A sweeping frequency method has been used to measure the spectrum of resonances in high-voltage varistors. As a result we can observe resonances that depend directly on inhomogeneity of the...
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An Estimation of the Efficiency of Public Research Institutes in Poland – DEA Approach
PublikacjaObjective: The purpose of this paper is to measure and assess the efficiency of research institutes in Poland. The institutes operate on the basis of various legal frameworks, but they serve a common purpose and have a joint area of activity, research and development.Research Design & Methods: We used the SBM model, a component of the non-parametric Data Envelopment Analysis (DEA) methodology, to analyse the efficiency...
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The effect of external load on ultrasonic wave attenuation in steel bars under bending stresses
PublikacjaThe stress state in deformed solids has a significant impact on the attenuation of an ultrasonic wave propagating through the medium. Measuring a signal with certain attenuation characteristics can therefore provide useful diagnostic information about the stress state in the structure. In this work, basic principles behind a novel attenuation-based diagnostic framework are introduced. An experimental study on steel bars under three-point...
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Time-Domain Description of Point-Source Acoustic Wavefields as a Useful Approach in Ultrasonic Techniques
PublikacjaIn traditional acoustics, field problems are usually treated in the frequency domain, broadband fields being reduced to superposition of harmonic spectrum components. However, this approach is inherently acausal and it is known that in case of arbitrary signals, the distribution-based, time-domain description can be more effective. The present paper is an attempt to expand the time-domain linear systems formalism onto space problems...
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Time-domain description of point-source acoustic wavefields as a useful approach in ultrasonic techniques
PublikacjaIn traditional acoustics, field problems are usually treated in the frequency domain, broadband fields being reduced to superposition of harmonic spectrum components. However, this approach is inherently acausal and it is known that in case of arbitrary signals, the distribution-based, time-domain description can be more effective. The present paper is an attempt to expand the time-domain linear systems formalism onto space problems...
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Ultrasonic-assisted Electrodeposition of Cu-Sn-TiO2 Nanocomposite Coatings with Enhanced Antibacterial Activity
PublikacjaCopper-based coatings are known for their high antibacterial activity. In this study, nanocomposite Cu–Sn–TiO2 coatings were obtained by electrodeposition from an oxalic acid bath additionally containing 4 g/dm3 TiO2 with mechanical and ultrasonic agitation. Ultrasound treatment was performed at 26 kHz frequency and 32 W/dm3 power. The influence of agitation mode and the current load on the inclusion and distribution of the TiO2...
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Current-based higher-order spectral covariance as a bearing diagnostic feature for induction motors
PublikacjaConducting the diagnosis of induction motors remotely by analyzing the supply current is an attractive prospect with the lack of access to the engine. Currently, there is no solution, based on analysis of the current, the credibility of which would allow its use in industry. The statistics of bearing failures in induction motors indicate that they constitute more than 40% of induction motor damage, therefore, bearing diagnosis...
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Impact of Demographic Changes onto National Economy Development
PublikacjaThe effects of population decline and their influence onto the national economy need to be analyzed with reference to modern demographic trends regarding society ageing process. The problem of demographic changes does not only concern the birth rate, life span and migration, but it also refers to economic phenomena and thus, the economic and demographic trend interrelation becomes quite obvious. Macroeconomic approach defines the...
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In search for new urban planning education and research formulas
PublikacjaThis paper shows research and educational urban planning projects based on international and mutlicultural cooperation including innovative elements to conduct research on built environment. Their common aim is to search for a new perspective on the city development and challenges resulting from changing conditions.
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Non-Destructive Assessment of Masonry Pillars using Ultrasonic Tomography
PublikacjaIn this paper, a condition assessment of masonry pillars is presented. Non-destructive tests were performed on an intact pillar as well as three pillars with internal inclusions in the form of a hole, a steel bar grouted by gypsum mortar, and a steel bar grouted by cement mortar. The inspection utilized ultrasonic stress waves and the reconstruction of the velocity distribution was performed by means of computed tomography. The...
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Research Trends of Vitamin D Metabolism Gene Polymorphisms Based on a Bibliometric Investigation
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Sensitivity analysis as a tool to optimise Human Development Index
PublikacjaResearch background: Composite indicators are commonly used as an approximation tool to measure economic development, the standard of living, competitiveness, fairness, effectiveness, and many others being willingly implemented into many different research disciplines. However, it seems that in most cases, the variable weighting procedure is avoided or erroneous since, in most cases, the so-called...
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MaliciousIDE – software development environment that evokes emotions
PublikacjaEmotions affect every aspect of human live, including work. Numerous studies in software engineering have shown that negative emotions can lower the productivity of programmers. Unlike traditional approaches to managing software development, modern methods, such as Agile and Lean, take into account human aspects of programming. To thoroughly investigate the impact of negative emotions on the work of programmers, a malicious integrated...
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Historical, technical and economic aspects of biogas development: Case Polanda and Ukraine
PublikacjaThe paper describes 3700 years of biogas manufacture with more details of last 120 years. Due to V. Omelianskij׳s researches 120 years ago, Ukrainians achieved a share in biogas manufacture in the overall biogas development. Poland started to take part in biogas development 96 years ago by finishing biogas plant in Posen 1928. History and current status of biogas plants achievements are collected and analyzed. Faults and achievements...
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Analiza SWOT i analiza 5 sił Portera dla rynku podstawowej opieki medycznej na obszarze miasta Gdańska
PublikacjaIn recent years we have seen the dynamic development of medical services sector inPoland. Private health centres focus on aggressive development strategy. The role of primaryhealth care facilities, which provide services financed from public funds, declined. The purpose of article is to describe medical services market in Gdańsk, especially in Gdańsk-South district. Itincludes demographics, the number and characteristics...
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Development of particle accelerator technology in Europe: digest of infrastructural and research projects
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A procedure for the identification of effective mechanical parameters of additively manufactured elements using integrated ultrasonic bulk and guided waves
PublikacjaThe subject of the current work was a simple but robust novel two-stage procedure for the non-destructive determination of effective elastic constants using ultrasonic wave propagation. First, ultrasonic bulk wave velocities measured on cubic samples were used to calculate most of the elements of the stiffness matrix. Secondly, the remaining elements were determined using the dispersion curves of elastic guided waves measured on...
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Automatic Credibility Assessment of Popular Medical Articles Available Online
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Future research directions in design of reliable communication systems
PublikacjaIn this position paper on reliable networks, we discuss new trends in the design of reliable communication systems. We focus on a wide range of research directions including protection against software failures as well as failures of communication systems equipment. In particular, we outline future research trends in software failure mitigation, reliability of wireless communications, robust optimization and network design, multilevel...
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DIRECTIONS OF THE SCIENTIFIC RESEARCH CONDUCTED IN THE DEPARTMENT OF MARINE AND POWER PLANTS OF THE FACULTY OF OCEAN ENGINEERING AND SHIP TECHNOLOGY OF THE GDANSK UNIVERSITY OF TECHNOLOGY
PublikacjaIn this article the short historical outline of the Department of Marine and Land Power Plants of the Faculty of Ocean Engineering and Ship Technology of the Gdansk University of Technology was introduced. Its activity beginnings, in the post-war history of the University, reach 1952. The leading scientific issues, which have been developed for years in three principal directions: design, manufacture and operation of machines and...
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Nonlinear control of five phase induction motor with synchronized third harmonic flux injection
PublikacjaThe paper deals with the novel control system for five phase induction motor (IM) that enables the injection of the rotor flux 3rd harmonic component. Two multiscalar models are transformed from the 1-1 and 2-2 vector models developed in the 1st and 3rd harmonic planes. Based on the obtained multiscalar models the synthesis of dual multiscalar control is established. The obtained two multiscalar control systems can independently...
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A Paradigm for HV, MV, LV Distribution Grid Development Planning
PublikacjaIn the literature, including that relating to businesses in the energy (and power) sector, the concept of these organizations’ operating paradigm may be found. The paper discusses the concept of the paradigm, with a focus on the power grid development planning paradigm. Against this background, issues related to energy security and power systems development trends and problems are presented. A new paradigm is proposed for distribution...
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Investigation on thermal changes of mechanical properties of textile fabric of National Stadium in Warsaw roof
PublikacjaSubject of the research is investigation of mechanical properties of technical fabric Précontraint 1202 S2 used for construction of the mobile part of roof of National Stadium in Warsaw. The research has been focused on fabric behavior in low temperature conditions. The main question which had to be answer has been: is it save to open and close the roof or keep the roof in the close position in winter conditions?
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DATA JOURNALS AND DATA PAPERS IN VARIOUS RESEARCH AREAS AND SCIENTIFIC DISCIPLINES – BIBLIOMETRIC ANALYSIS BASED ON INCITES
PublikacjaThe main aim of this work is to provide insight into a bibliometric analysis of Data Journals and Data Papers in terms of research areas, disciplines, publication year and country. In particular, we calculated many bibliometric indicators, especially: the number of publications and citations. Furthermore, this work also investigated the top 20 journals in which scientists published the largest number of Data Papers. It was found...
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Revalorisation of the Szewalski’s concept of the law of varying the last-stage blade retraction in a gas-steam turbine
PublikacjaThe article presents the implementations of the free vortex law to the blade of the last stage of a gas-steam turbine. First, a thermodynamic analysis was carried out, determining the parameters at the inlet, then the number of stages of the high and low-pressure part of the turbine was constructed, together with the kinematics and velocity vectors for subsequent stages of the axial turbine. The last step of article was to take...
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Children’s Astronomy. Development of the Shape of the Earth Concept in Polish Children between 5 and 10 Years of Age
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Noise and Electro-Ultrasonic Spectroscopy of Conducting PolymerThick Films
PublikacjaThick conducting films based on conducting polymer are characterized by DC conductivity and noise in temperature range 10 to 300 K. Conducting polymers could be used e.g. for the top electrode (cathode) in the solid tantalum or niobium capacitors. On the conducting polymer layer the top layer of carbon/graphite and/or silver polymer based pastes is applied in the capacitor technology. Our samples structure consists of conducting...
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Winding function approach based design of novel five-phase brushless doubly fed induction generator
PublikacjaThe paper presents the concept of the new design of the five-phase brushless doubly fed induction generator. The generator is dedicated to the modern wind turbine. The innovative design approach uses a five-phase power supply from the stator control winding side of the generator with a stator three-phase classic power winding. The research results presented indicate that the electromagnetic coupling between the control and power...
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Wind Conditions in Urban Layout – Numerical and Experimental Research
PublikacjaThis paper presents research which compares the numerical and the experimental results for different cases of airflow around a few urban layouts. The study is concerned mostly with the analysis of parameters, such as pressure and velocity fields, which are essential in the building industry. Numerical simulations have been performed by the commercial software Fluent, with the use of a few different turbulence models, including...
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Application of ion chromatography with pulsed amperometric detection for the determination of trace cyanide in biological samples, including breast milk
PublikacjaCyanide (CN) is the biomarker of exposure to the components of tobacco smoke, although its presence in biological samples is also due to the consumption of products containing cyanogenic glycosides. In this work, we determine the concentration of the free cyanide in urine, saliva and breast milk matrices, using ion chromatography with pulsed amperometric detection (IC-PAD). IC-PAD is an emerging method, with only few documented...
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New Gene Markers of Angiogenesis and Blood Vessels Development in Porcine Ovarian Granulosa Cells during Short-Term Primary Culture In Vitro
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Selected biotrends in development of epoxy resins and their composites
PublikacjaEpoxy resins and their fibre or particulate composites are widely used in various industries, including building, naval, aircraft, automotive and aerospace. Modern polymer science and technology focus on the development of green polymers and composites. There are two major areas of interest in the case of epoxy resins: the development of bio-based resins and the production of composites with natural fibers. One of the most interesting...
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Analytical Traffic Model for a Multidomain IMS/NGN Network Including Service and Transport Stratum
PublikacjaThis paper addresses the problem of modelling call processing performance (CPP) in a multidomain Next Generation Network (NGN) architecture including the elements of the IP Multimedia Subsystem (IMS) in service stratum and based on the Multiprotocol Label Switching (MPLS) technology in transport stratum. An analytical traffic model for such an architecture is proposed by integrating the formerly implemented submodels of service...
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Self-employment of women: an opportunity or the last resort?
PublikacjaIt is believed that automatization and technological changes will be the main drivers of work in the future. At the same time, there is a growing discussion about new forms of employment, such as self-employment. It may be either perceived as a chance for empowerment, through creating new job opportunities, that were not reachable previously, or as precarious work, with less stability, higher risk, and uncertain income. The main...
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CROWDFUNDING OF RESEARCH PROJECTS IN POLAND
PublikacjaCrowdfunding recently became a very popular way of funding, which allows funding almost everything, from minor personal projects to expensive commercial ones, as long as we can find investors. It may also be a new opportunity for entrepreneurial researchers, who may attract capital investment in companies that are promised to own developed technologies. Social financing of science is well suited to reduce some of the biggest problems...
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Stardust - Investigation of Microbes in the Stratosphere
PublikacjaThe stratospheric microbiome has been investigated several times using the methods of classical microbiology. In this experiment, we have combined them with some novel approaches including whole- metagenome amplification, Maldi TOF mass spectrometry and Sanger DNA sequencing. The results of the experiment may provide the scientists with knowledge about the mechanisms of survivability of microorganisms in stratospheric conditions...
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Five-phase Induction Motor Drive Operation During Stator Phase Fault
PublikacjaThe article presents the most important advantages of multi-phase electric drives. The construction of a five-phase squirrel cage induction motor together with possible stator winding distribution cases is presented, which affect the properties of such motor. Increased reliability of five-phase drives was indicated. The drive operation properties were confirmed by experimental results.
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Experimental and theoretical investigation into pressure field in a shroud clearance. Part I: Experimental research
PublikacjaPrzedstawiono wyniki badań eksperymentalnych rozkładu ciśnienia w uszczelnieniu nadbandażowym stopnia powietrznej turbiny modelowej. Badania przeprowadzono dla różnej częstości obrotowej wirnika i różnego obciążenia turbiny. Wyniki porównano z rezultatami obliczeń teoretycznych w II części artykułu.
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New approach to noncausal identification of nonstationary stochastic systems subject to both smooth and abrupt parameter changes
PublikacjaIn this paper we consider the problem of finiteintervalparameter smoothing for a class of nonstationary linearstochastic systems subject to both smooth and abrupt parameterchanges. The proposed parallel estimation scheme combines theestimates yielded by several exponentially weighted basis functionalgorithms. The resulting smoother automatically adjustsits smoothing bandwidth to the type and rate of nonstationarityof the identified...
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Affective Learning Manifesto – 10 Years Later
PublikacjaIn 2004 a group of affective computing researchers proclaimed a manifesto of affective learning that outlined the prospects and white spots of research at that time. Ten years passed by and affective computing developed many methods and tools for tracking human emotional states as well as models for affective systems construction. There are multiple examples of affective methods applications in Intelligent Tutoring Systems (ITS)....
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Diagnosis of bearing damage in induction motors by instantaneous power analysis
PublikacjaResearch 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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Hybrid geothermal-fossil power cycle analysis in a Polish setting with a focus on off-design performance and CO2 emissions reductions
PublikacjaGrowing demand for electricity due to economic development contributes to increased greenhouse gas production, especially CO2. However, emissions can be limited by enhancing the efficiency of primary energy conversion, such as integrating geothermal energy into coal-fired power plants. Therefore, this paper proposes replacing conventional feed-water heaters with geothermal preheaters to create a hybridized system. This study was...
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Research on entrepreneurship – the forms of entrepreneurship
PublikacjaThe aim of this article is to present suggestions for future directions of research on entrepreneurship, with particular emphasis on different forms of entrepreneurship. The suggestions are preceded by a brief review of research on entrepreneurship. The article is theoretical in nature and does not present any own research, although its content is based on multiple years of experience in studying this phenomenon. The forms of entrepreneurship...
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Buenos Aires – Toward Comprehensive Development and Sustainable Mobility
PublikacjaThis paper is introducing Buenos Aires’ achievements and challenges in implementing comprehensive development and integrating efficient and sustainable transport system within its urban structure. There are several important steps in this process starting from urban regeneration of Puerto Madero, the introduction and then implementation of a strategic plan Modelo territorial (2010) and of Buenos Aires' Plan de Movilidad Sustentable...
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Novel Investigation of Higher Order Spectral Technologies for Fault Diagnosis of Motor-Based Rotating Machinery
PublikacjaIn the last decade, research centered around the fault diagnosis of rotating machinery using non-contact techniques has been significantly on the rise. For the first time worldwide, innovative techniques for the diagnosis of rotating machinery, based on electrical motors, including generic, nonlinear, higher-order cross-correlations of spectral moduli of the third and fourth order (CCSM3 and CCSM4, respectively), have been comprehensively...
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Enhanced European Coordination of Accelerator Research and Development – EuCARD2 – Global and Local Impact
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