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Search results for: GENERALIZED CARNOT CYCLE
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Application of the F-statistic of the Fisher-Snedecor distribution to analyze the significance of the effect of changes in the compression ratio of a diesel engine on the value of the specific enthalpy of the exhaust gas flow
PublicationThe paper discusses the impact of changes in the compression ratio on the operating parameters of a diesel engine, e.g. on the temperature of exhaust gases. It presents the construction of the laboratory test stand, on which experimental measurements were realized. It is characterized how the actual changes of the compression ratio were introduced to the existing engine. The program of experimental investigations taking into account...
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Experimental investigations and damage growth modeling of EN‐AW 2024 aluminum alloy under LCF loading accounting creep pre‐deformation
PublicationThis article presents the results of experimental tests of creep rupture and of low-cycle fatigue (LCF) of EN-AW 2024 aluminum alloy devoid of damage and having preliminary damage. The preliminary damage was dealt in the process of creep at elevated temperature 100C, 200C, and 300C until achievement of two different strain values at each temperature. Samples with preliminary damage were subjected to fatigue tests at room temperature....
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Thermochemical Conversion of Biomass and Municipal Waste into Useful Energy Using Advanced HiTAG/HiTSG Technology
PublicationAn advanced thermal conversion system involving high-temperature gasification of biomass and municipal waste into biofuel, syngas or hydrogen-rich gas is presented in this paper. The decomposition of solid biomass and wastes by gasification is carried out experimentally with a modern and innovative regenerator and updraft continuous gasifier, among others. A ceramic high-cycle regenerator provides extra energy for the thermal conversion...
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Od postawy prozdrowotnej w stoczni jachtowej do ograniczania zagrożeń na stanowisku pracy formierza-laminiarza
PublicationTematyka zdrowia i bezpieczeństwa pracowników, coraz częściej popularyzowana w świecie biznesu, nadal stanowi dość mało rozpoznany obszar działalności polskich przedsiębiorstw. Niniejszy artykuł porusza ważką kwestię promocji zdrowia w miejscu pracy jako czynnika zwiększającego efektywność pracy oraz jego wpływ na osiąganie wysokiej jakości produktu. Publikacja omawia znaczenie postawy prozdrowotnej i sposobów jej kształtowania...
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Model of an Integration Bus of Data and Ontologies of Smart Cities Processes
PublicationThis paper presents a model of an integration bus used in the design of Smart Cities system architectures. The model of such a bus becomes necessary when designing high-level architectures, within which the silo processes of the organization should be seen from the perspective of its ontology. For such a bus to be used by any city, a generic solution was proposed which can be implemented as a whole or in part depending on the requirements...
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On adaptive covariance and spectrum estimation of locally stationary multivariate processes
PublicationWhen estimating the correlation/spectral structure of a locally stationary process, one has to make two important decisions. First, one should choose the so-called estimation bandwidth, inversely proportional to the effective width of the local analysis window, in the way that complies with the degree of signal nonstationarity. Too small bandwidth may result in an excessive estimation bias, while too large bandwidth may cause excessive...
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Cavity-expansion approximation for projectile impact and penetration into sand
PublicationA one-dimensional problem of a spherical cavity expanding at a constant velocity from zero initial radius in an infinite granular medium, which has the first-kind self-similar solution, is considered. We are solving this dynamic spherical cavity-expansion problem to model rigid spheres penetrating into a granular media. Elastic–plastic deformation of the granular media is described in a barotropic approximation, using the high-pressure...
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Load path sensitivity and multiaxial fatigue life prediction of metals under non-proportional loadings
PublicationEngineering components often operate under complex loadings, in which the variable amplitude multiaxial stresses are raised by geometric discontinuities including holes, grooves, fillets and shoulders, etc. Besides, the non-proportional loading will lead to the rotation of maximum principal stress/strain and additional fatigue damage of structural elements in service. Consequently, the multiaxial and non-proportional loading have...
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Extended micropolar approach within the framework of 3M theories and variations thereof
PublicationAs part of his groundbreaking work on generalized continuum mechanics, Eringen proposed what he called 3M theories, namely the concept of micromorphic, microstretch, and micropolar materials modeling. The micromorphic approach provides the most general framework for a continuum with translational and (internal) rotational degrees of freedom (DOF), whilst the rotational DOFs of micromorphic and micropolar continua are subjected...
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On nonlinear dilatational strain gradient elasticity
PublicationWe call nonlinear dilatational strain gradient elasticity the theory in which the specific class of dilatational second gradient continua is considered: those whose deformation energy depends, in an objective way, on the gradient of placement and on the gradient of the determinant of the gradient of placement. It is an interesting particular case of complete Toupin–Mindlin nonlinear strain gradient elasticity: indeed, in it, the...
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Jednoelektronowy atom Diraca w słabym polu magnetycznym
PublicationW rozprawie przedstawiono opis wpływu zewnętrznego stałego, słabego, jednorodnego pola magnetycznego na jednoelektronowy atom Diraca. Wykorzystując funkcje gęstości ładunku elektrycznego oraz gęstości prądu elektrycznego, rozważono procesy indukowania się w atomie dodatkowych elektromagnetycznych momentów multipolowych. Dokonano analizy indukowanego momentu dipolowego, w wyniku której uzyskano wyrażenie dla magnetyzowalności atomu....
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Identification of damages in the inlet air duct of a diesel engine based on exhaust gas temperature measurements
PublicationThe temperature of the exhaust gas of a diesel piston engine, measured in the characteristic control sections of its thermo-flow system, can be a valuable source of diagnostic information about the technical condition of the elements limiting the working spaces thus separated, including the turbocharging system, but also its fuel supply system and replacement of the medium. In standard marine engine measurement systems equipped...
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Road Infrastructure Safety Management in Poland
PublicationThe objective of road safety infrastructure management is to ensure that when roads are planned, designed, built and used road risks can be identified, assessed and mitigated. Road transport safety is significantly less developed than that of rail, water and air transport. The average individual risk of being a fatality in relation to the distance covered is thirty times higher in road transport that in the other modes. This is...
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Carbon dioxide sequestration by industrial wastes through mineral carbonation: Current status and perspectives
PublicationMineral carbonation using natural minerals or industrial wastes is a safe and promising strategy for CO2 sequestration. Application of industrial wastes for this purpose has significant ecological and environmental value, which is one of the key green technologies in the global carbon mitigation. This review summarizes the current research status of CO2 mineralization by industrial wastes. This work surveys the mechanisms and capacities...
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Analysis of the Possibility of Using New Types of Protective Coatings and Abrasion-Resistant Linings under the Operating Conditions of the Spiral Classifier at KGHM Polska Miedź S.A. Ore Concentration Plant
PublicationA study was carried out to select the appropriate coatings for corrosion protection of the spiral classifier working at KGHM Polska Miedź S.A. Ore Concentration Plant. The abrasion resistance of selected protective coatings and wear-resistant linings was investigated using a DT-523 rotary abrasion tester with Taber CS-10 rubber abrasive discs. The average weight loss of the coatings after a cycle of 2000 revolutions was determined....
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Neoclassical Navier–Stokes Equations Considering the Gyftopoulos–Beretta Exposition of Thermodynamics
PublicationThe seminal Navier-Stokes equations were stated even before the creation of the foundations of thermodynamics and its first and second laws. There is a widespread opinion in the literature on thermodynamic cycles that the Navier-Stokes equations cannot be taken as a thermodynamically correct model of a local "working fluid", which would be able to describe the conversion of "heating" into "working" (Carnot's type cycles) and vice...
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Assembling and testing of quasi-static hybrid piezoelectric motor based on electroactive lubrication principle
PublicationThe presented paper concerns a novel concept of hybrid piezoelectric motor based on electroactive lubrication principle. Its structure is combined of quasi-static and resonance piezoelectric actuators, synchronizing their work to generate the rotary movement. The hybrid motor topology is compared to the existing piezoelectric motors, regarding its field of applications in embedded systems with very high security requirements. The...
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Design and distribution of air nozzles in the biomass boiler assembly
PublicationDue to energy crisis as well as increasing pollution of the environment, renewable energy sources usage increases all over the world. These facts encouraged authors to start research over developing a uniform biomass boiler calculation model. This paper presents a design of biomass boiler assembly created for ORC (Organic Rankine Cycle) unit since these systems could achieve strong position in energy industry....
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Warstwowy system zabezpieczeń w przemysłowych instalacjach podwyższonego ryzyka
PublicationRozdział poświęcono aktualnym zagadnieniom analizy i projektowania warstw zabezpieczeń w kontekście oceny ryzyka i zarządzania bezpieczeństwem funkcjonalnym w cyklu życia z wyróżnieniem trzech warstw: (1) podstawowego systemu sterowania BPCS (basic process control system), (2) człowieka-operatora korzystającego opcjonalnie z systemu alarmowego AS (alarm system) oraz (3) przyrządowego systemu bezpieczeństwa SIS (safety instrumented...
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Development of chromatographic and mass spectrometry conditions for untargeted lipidomic analysis of human breast milk
PublicationHuman breast milk (HBM) is a complex biofluid containing components which are essential for the proper growth of the newborn (for example nutrients such as carbohydrates, proteins, lipids) and also bioactive substances. According to the literature, most of studies involving HBM nutrients investigations focused essentially on the determination of proteins. The molecular composition of lipids in HBM is not well known as the protein...
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Implementing Smart Virtual Product Development (SVPD) to Support Product Manufacturing
PublicationThis paper illustrates the concept of providing the manufacturing knowledge during early stages of product life cycle to experts working on product development. The aim of this research is to enable a more collaborative product development environment by using Smart Virtual Product Development (SVPD) system, which is powered by Set of Experience Knowledge Structure (SOEKS) and Decisional DNA (DDNA). It enhances the industrial product...
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Smart experience engineering to support collaborative design problems based on constraints modelling
PublicationEngineering design is a knowledge intensive process. Experts' experiences from different product life-cycle stages play a key role in problem solving during design decision making by linking up knowledge to find better solutions for a specific design problem. Different approaches have been used to support Collaborative and Concurrent Product Design, such as Constraint Satisfaction Problem (CSP) modelling. Additionally, due to the...
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The Comparison of the Crypto- and Fiat Currencies’ Exchange Rate Volatility in The Years 2015–2017
PublicationThe article describes the issues related to exchange rate volatility of crypto- and fiat currencies. The first part presents the issue of exchange rate volatility as well as methods of its evaluation and criteria of the conducted research. In the next part the author presented the essence of currencies and the main currency i.e. fiat money in the global economy in terms of the volume of transactions on the FOREX market. Then the...
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Influence of reactive oxygen species during deposition of iron oxide films by high power impulse magnetron sputtering.
PublicationIron oxide films were deposited using high power impulse magnetron sputtering (HiPIMS) of an iron cathode in an argon/oxygen gas mixture at different gas pressures (0.5~Pa, 1.5~Pa, and 5.0~Pa). The HiPIMS system was operated at a repetition frequency $f = 100$~Hz with a duty cycle of 1~\%. A main goal is a comparison of film growth during conventional and electron cyclotron wave resonance-assisted HiPIMS. The deposition plasma...
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Cooperation of mono- and bi-articular muscles: human lower limb
PublicationObjectives: The aim of this study was to create and analyze a Pareto-optimal problem that would describe cooperation between mono- and bi-articulate lower limb muscles in sagittal plane. Methods: Equations describing the problem were derived and analyzed, additional constrains were introduced and experimental verification based on gait video analysis was performed. Results: Uncertainty of Pareto-optimal solution is shown for the...
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HIGH TEMPERATURE HEAT PUMPS – PERSPECTIVE HEATING SYSTEMS?
PublicationIn the paper presented are authors own concepts of high temperature compressor heat pumps for the utilisation of medium and low temperature sources of heat. Working fluids for use in high temperature heat pumps are discussed, as well as the criteria for their selection. Analyses are presented for the production of in the upper steam source at 130 °C. One-stage systems and cascade systems were analyzed. An analysis of the coefficient...
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Adoption of the F-statistic of Fisher-Snedecor distribution to analyze importance of impact of modifications of injector opening pressure of a compression ignition engine on specific enthalpy value of exhaust gas flow
PublicationThis article analyzes the effect of modifications of injector opening pressure on the operating values of a compression ignition engine, including the temperature of the fumes. A program of experimental investigation is described, considering the available test stand and measurement capabilities. The structure of the test stand on which the experimental measurements were conducted is presented. The method of introducing real modifications...
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Organic syntheses greenness assessment with multicriteria decision analysis
PublicationGreen chemistry requires a metrics system that is comprehensive by the criteria included and simple in the application at the same time. We propose the application of multicriteria decision analysis for com- parative greenness assessment of organic synthesis procedures. The assessment is based on 9 criteria (the reagent, reaction efficiency, atom economy, temperature, pressure, synthesis time, solvent, catalyst and reactant) for...
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Multiaxial Fatigue Behaviour of SLM 18Ni300 Steel
PublicationFatigue behaviour of SLM 18Ni300 steel under proportional bending-torsion loading is studied. The fatigue tests are conducted under pulsating loading conditions using tubular specimens with a transversal circular hole. Three ratios of the normal stress to shear stress are considered, namely σ/τ=4,σ/τ=2 and σ/τ = 4/3. Crack initiation sites were found for two diametrically opposite points around the hole, whose locations are governed...
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On the production of electricity in Poland using a geothermal binary power plant - A thermodynamic overview - Part I
PublicationPoland has a significant potential of geothermal energy. However, the high-temperature sources that are needed to drive power plants are found in relatively few places. Therefore, the objective of this paper is to consider any location in the northern part of Poland as a possible place to build a binary power plant. A scientific research was confirmed the existence of an elevated temperature gradient in this region. The hot rocks...
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The importance of trust and altruistic social orientation for COVID-19 distress
PublicationBackground: The COVID-19 pandemic, the biggest global health crisis in decades, has been a difficult experience for nations all over the world. In the present study we wanted to assess to what extent a positive attitude towards others, expressed in altruistic social orientation and a high level of trust, would be linked to lower levels of COVID-19 distress in infected and non-infected individuals. Participants and procedure:...
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Belief in the importance of socially responsible behaviors – the significance of trust and personal experiences with COVID-19
PublicationA vast number of studies have shown that trust is related to socially desirable traits and behaviors. In the present research we have investigated the relationship between generalized trust and beliefs about the importance of socially responsible behaviors (SRB) during the pandemic – namely, following the sanitary regime and getting vaccinated. Basing on the previous findings we assumed that trustful people...
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Broken rotor symptoms in the sensorless control of induction machine
PublicationThe purpose of this paper is to investigate the need for a universal method for sensorless controlled induction motor drive diagnosis. The increasing number of sensorless control systems in industrial applications require a universal method for the drive diagnosis, which provides reliable diagnostic reasoning independent of control system structure and state variables measurement or estimation method.Simulations and experimental...
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Cross-talk Between the Heart and Arteries in Older 65+ Adults
PublicationRegulatory synchronization between the heart and the arterial walls is essential for optimal blood delivery to tissues. We investigated functional coherence between heart rhythm and aortic wall compliance in 30 volunteers aged 65 – 74. ECG and carotid and iliac pulse-wave were recorded and digitized at 2 kHz. Carotid-femoral pulse-wave transit time (cfTT) which reflex aortic compliance was assessed using the intersecting tangent...
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Analytical calculations of scattering lengths for a class of long-range potentials of interest for atomic physics
PublicationWe derive two equivalent analytical expressions for an $l$th partial-wave scattering length $a_{l}$ for central potentials with long-range tails of the form % \begin{math} \displaystyle V(r)=-\frac{\hbar^{2}}{2m}\frac{Br^{n-4}}{(r^{n-2}+R^{n-2})^{2}} -\frac{\hbar^{2}}{2m}\frac{C}{r^{2}(r^{n-2}+R^{n-2})}, \end{math} % ($r\geqslant r_{s}$, $R>0$). % For $C=0$, this family of potentials reduces to the Lenz potentials discussed in...
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Stream Reasoning to Improve Decision-Making in Cognitive Systems
PublicationABSTRACT Cognitive Vision Systems have gained a lot of interest from industry and academia recently, due to their potential to revolutionize human life as they are designed to work under complex scenes, adapting to a range of unforeseen situations, changing accordingly to new scenarios and exhibiting prospective behavior. The combination of these properties aims to mimic the human capabilities and create more intelligent and efficient...
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Generalization of Kramers-Krönig relations for evaluation of causality in power-law media
PublicationClassical Kramers-Krönig (K–K) relations connect real and imaginary parts of the frequency-domain response of a system. The K–K relations also hold between the logarithm of modulus and the argument of the response, e.g. between the attenuation and the phase shift of a solution to a wave-propagation problem. For square-integrable functions of frequency, the satisfaction of classical K–K relations implies causality in the time domain....
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Short-Term Price Reaction to Filing for Bankruptcy and Restructuring Proceedings—The Case of Poland
PublicationThis study aims to check market reaction to filing for bankruptcy and restructuring proceedings and to verify the short-term effect of a price reversal in the Polish market in the years 2004–2019. The research was conducted by dividing the analysed companies according to the procedure (bankruptcy and restructuring) and market (the main market and the NewConnect market). The research methodology used in the study is the event analysis...
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FEM modelling of screw displacement pile interaction with subsoil
PublicationPredicting the-settlement characteristics of piles is an important element in the designing of pile foundations. The most reliable method in evaluating pile-soil interaction is the static load test, preferably performed with instrumentation for measuring shaft and pile base resistances. This, however, is a mostly post-implementation test. In the design phase, prediction methods are needed, in which numerical simulations play an...
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Entrepreneurial competencies and intentions among students of technical universities
PublicationThe study investigates the entrepreneurial competencies and intentions of students. Their formation is a requirement of modern times. The question arises whether students of modern technical universities get entrepreneurial competencies and whether they transform these competencies into their entrepreneurial intentions. More than 3.6 thousand students from six technical universities from Poland, Ukraine, Latvia, Bulgaria, and Lithuania...
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Simulator for Performance Evaluation of ASON/GMPLS Network
PublicationThe hierarchical control plane network architecture of Automatically Switched Optical Network with utilization of Generalized Multi-Protocol Label Switching protocols is compliant to next generation networks requirements and can supply connections with required quality of service, even with incomplete domain information. Considering connection control, connection management and network management, the controllers of this architecture...
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Theoretical examination of the fracture behavior of BC3 polycrystalline nanosheets: Effect of crack size and temperature
Publication2D carbon graphene nanostructures are elements of advanced materials and systems. This theoretical survey provides explanation to the mechanical and fracture behavior of mono- and polycrystalline BC3 nanosheets (denoted as MC- and PCBC3NS, respectively) as a function of temperature and the type of crack defects. The mechanical performance of PCBC3NS at elevated temperatures was monitored varying the number of grain boundaries (the...
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Modeling nutrient removal and energy consumption in an advanced activated sludge system under uncertainty
PublicationActivated sludge models are widely used to simulate, optimize and control performance of wastewater treatment plants (WWTP). For simulation of nutrient removal and energy consumption, kinetic parameters would need to be estimated, which requires an extensive measurement campaign. In this study, a novel methodology is proposed for modeling the performance and energy consumption of a biological nutrient removal activated sludge system...
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Rigorous numerics for critical orbits in the quadratic family
PublicationWe develop algorithms and techniques to compute rigorous bounds for finite pieces of orbits of the critical points, for intervals of parameter values, in the quadratic family of one-dimensional maps fa(x)=a−x2. We illustrate the effectiveness of our approach by constructing a dynamically defined partition P of the parameter interval Ω=[1.4,2] into almost 4 million subintervals, for each of which we compute to high precision the...
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eFRADIR: An Enhanced FRAmework for DIsaster Resilience
PublicationThis paper focuses on how to increase the availability of a backbone network with minimal cost. In particular, the new framework focuses on resilience against natural disasters and is an evolution of the FRADIR/FRADIR-II framework. It targets three different directions, namely: network planning, failure modeling, and survivable routing. The steady state network planning is tackled by upgrading a sub-network (a set of links termed...
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Analiza możliwości odzyskiwania ciepła odpadowego w przemyśle rafineryjnym z wykorzystaniem układów ORC
PublicationJednym z najważniejszych zagadnień współczesnej techniki jest poszukiwanie nowych możliwości pozyskiwania energii elektrycznej poprzez zagospodarowanie dotychczas niewykorzystanych lub bezużytecznie marnowanych jej źródeł. Jest to niezwykle ważna kwestia zarówno z ekonomicznego, technologicznego, jak i środowiskowego punktu widzenia. Jednym z przykładów nowoczesnych rozwiązań w tej dziedzinie może być zastosowanie układu opartego...
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Partial Admission Stages of High Efficiency for a Microturbine
PublicationThe paper presents the results of a design analysis of a microturbine for a cogeneration micro-power plant working in accordance with organic Rankine cycle. The heat power of the plant is assumed equal to 20kW and the corresponding available electric output is estimated to be about 3 kW. After the design analysis, the axial turbine with partial admission in all stages was built and tested experimentally. Special attentionwas paid...
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Gazowa mikrosiłownia domowa z modułem ORC - doświadczenia z badania prototypu
PublicationArtykuł zawiera rozważania nad ideą wykorzystania obiegu parowego ORC (Organic Rankine Cycle) do skojarzonej produkcji ciepła i energii elektrycznej dla pokrycia potrzeb indywidualnego odbiorcy. Dokonano w nim podsumowania dotychczasowych prac prowadzonych przez Autorów, które zaowocowały budową demonstracyjno-badawczego stanowiska mikro-CHP z technologią ORC w skali „domowej”, współpracującą z komercyjnym kotłem gazowym. W publikacji...
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The conception of energetic investigations of the multisymptom fatigue of the simple mechanical systems' constructional materials
PublicationThe article presents the basic assumptions of the research project aimed, as the main scientific purpose, an identification of the slow-changeable energy processes surrounding the high-cycle fatigue of constructional materials within the plain mechanical system, especially the marine one, for diagnostic purposes. There is foreseen an application of alternative diagnostic methods based on energetic observations of the multi-symptom,...
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Partial Admission Stages of High Efficiency for a Microturbine
PublicationThe paper presents the results of a design analysis of a micro-turbine for a co-generation micro-power plant working in accordance with organic Rankine cycle. The heat power of the plant is assumed equal to 20kW and the corresponding available electric output is estimated to be about 3kW. After the design analysis, the axial turbine with partial admission in all stages was built and tested experimentally. Special attention was...