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Wyszukujesz frazę "Jaworski, M." wg kryterium: Autor


Wyświetlanie 1-10 z 10
Tytuł:
Entropy generation in a condenser and related correlations
Autorzy:
Laskowski, R.
Jaworski, M.
Smyk, A.
Powiązania:
https://bibliotekanauki.pl/articles/240683.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steam condenser
entropy generation
kondensator pary
generowanie entropii
Opis:
The paper presents an analysis of relations describing entropy generation in a condenser of a steam unit. Connections between entropy generation, condenser ratio, and heat exchanger effectiveness, as well as relations implied by them are shown. Theoretical considerations allowed to determine limits of individual parameters which describe the condenser operation. Various relations for average temperature of the cold fluid were compared. All the proposed relations were verified against data obtained using a simulator and actual measurement data from a 200 MW unit condenser. Based on data from a simulator it was examined how the sum of entropy rates, steam condenser effectiveness, terminal temperature difference and condenser ratio vary with the change in the inlet cooling water temperature, mass flow rate of steam and the cooling water mass flow rate.
Źródło:
Archives of Thermodynamics; 2015, 36, 2; 27-48
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Possibility of using adsorption refrigeration unit in district heating network
Autorzy:
Grzebielec, A.
Rusowicz, A.
Jaworski, M.
Laskowski, R.
Powiązania:
https://bibliotekanauki.pl/articles/240811.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
refrigeration
adsorption refrigeration
air conditioning
district heating network
chłodzenie
absorpcja
klimatyzacja
sieć ciepłownicza
Opis:
Adsorption refrigeration systems are able to work with heat sources of temperature starting with 50°C. The aim of the article is to determine whether in terms of technical and economic issues adsorption refrigeration equipment can work as elements that produce cold using hot water from the district heating network. For this purpose, examined was the work of the adsorption air conditioning equipment cooperating with drycooler, and the opportunities offered by the district heating network in Warsaw during the summer. It turns out that the efficiency of the adsorption device from the economic perspective is not sufficient for production of cold even during the transitional period. The main problem is not the low temperature of the water supply, but the large difference between the coefficients of performance, COPs, of adsorption device and a traditional compressor air conditioning unit. When outside air temperature is 25°C, the COP of the compressor type reaches a value of 4.49, whereas that of the adsorption device in the same conditions is 0.14. The ratio of the COPs is 32. At the same time ratio between the price of 1 kWh of electric power and 1 kWh of heat is only 2.85. Adsorption refrigeration equipment to be able to compete with compressor devices, should feature COPads efficiency to be greater than 1.52. At such a low driving temperature and even changing the drycooler into the evaporative cooler it is not currently possible to achieve.
Źródło:
Archives of Thermodynamics; 2015, 36, 3; 15-24
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparative study of thermodynamic electrolyte models applied to the Solvay soda system
Autorzy:
Jaworski, Z.
Czernuszewicz, M.
Gralla, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/185481.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
model termodynamiczny
elektrolit
thermodynamic model
electrolytes
activity coefficients
soda system
Opis:
Fast development of computation techniques for electrolyte activities contributed recently to introduction of a few substantial programmes for thermodynamic computing of multiphase systems. The presented study comprises useful information for practical computing using selected thermodynamic models of aqueous electrolyte solutions. Those models enable quantitative description of both phase and ionic equilibria and provide values of activity coefficients. The carried out analysis of individual models involved a comparison of their practical effectiveness features along with problems encountered in evaluation of the coefficients. The authors conclude that for the Solvay soda system the exUNIQUAC model for an in-house code or the MSE model for a commercial one can be used.
Źródło:
Chemical and Process Engineering; 2011, 32, 2; 135-154
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Principles of the toll roads pricing
Autorzy:
Jaworski, P.
Liberadzki, K.
Liberadzki, M.
Powiązania:
https://bibliotekanauki.pl/articles/224057.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
transportation
PPPs projects
Public-private partnerships
toll roads
Engel curves
Tőrnquist function
transport
projekt PPP
partnerstwa publiczno-prywatnego
drogi płatne
krzywe Engla
funkcja Tőrnquist
Opis:
In this paper the authors refer to the method of commercial provision of road infrastructure called BOT (build-operate-transfer) under Public-private partnerships (PPPs) scheme. First we present the investment criteria for transportation PPP projects as well as application of price theory. Then we recognize that the different participants in PPP projects have distinct goals and requirements that must be met in order for them to be able to participate in an effective partnership. The main challenge for the toll road pricing is to determine the economically viable toll rate that takes into consideration the diverse and sometimes conflicting interests of different stakeholders involved in the project. The main objective is to review the theory of economic principles for optimal toll roads pricing and to review the existing approaches to transportation projects appraisal. Then the authors show how to formally derive the condition for toll rate that meets 2 criteria: 1) is socially optimal and 2) covers operator’s costs. For this purpose we use II type Tőrnquist function, a member of an Engel family of functions. This function models the relationship between income and consumption of inferior and normal goods. Tőrnquist function is a mathematical representation of the well-known Engel curves. These curves record the relationship between the quantity of goods purchased and total income. They are not necessarily straight lines. The demand for some “luxury” goods may increase proportionally more rapidly than income, whereas the demand for “necessities” may grow proportionally less rapidly than income. The precise shape will depend on the individual’s preferences for goods as reflected in the indifference curve map. We deem the highway trip to be a “second necessity good”. There is number of economists who apply the Tőrnquist function for microeconomic analysis. The extremely simple form of the Tőrnquist function allows to get the solution in a closed form.
Źródło:
Archives of Transport; 2018, 45, 1; 53-62
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and theoretical modeling of waste combustion in a chamber with a moving grate
Autorzy:
Jaworski, T. J.
Pikoń, K.
Kajda-Szcześniak, M.
Powiązania:
https://bibliotekanauki.pl/articles/185559.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
waste
combustion
physicochemical properties
emission of gas combustion products
quantitative evaluation indicators
marnotrawstwo
spalanie
właściwości fizykochemiczne
Opis:
The work contains a description of a developed experimental and theoretical method of modeling of solid waste combustion in a device equipped with a moving grate and capability to optimize the work of waste incineration plant. Implementation of this issue was based on results of experimental studies made on a laboratory scale boiler. This was possible by defining and testing indicators of quantitative assessment of combustion such as: reaction front rate, ignition rate, the rate of combusted mass loss and the heat release rate. These indicators as measurable "criteria indicators" allow transfer of parameters from a laboratory-scale unit, working in the transient egime into an industrial full scale grate device working continuously in stable determined conditions. This allows for wide optimization possibilities in the operation of a waste incineration plant, in particular the combustion chamber, equipped with a moving grate system.
Źródło:
Chemical and Process Engineering; 2018, 39, 1; 3-14
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A review of the numerical studies on planar and tubular solid oxide fuel cells within four EU projects of the 7th framework programme
Autorzy:
Pianko-Oprych, P.
Jaworski, Z.
Zinko, T.
Palus, M.
Powiązania:
https://bibliotekanauki.pl/articles/185086.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Solid Oxide Fuel Cell
stack
fuel cell system
Computational Fluid Dynamics
CFD
Finite Element Method
FEM
modelling
process simulation
ogniwo paliwowe z tlenkiem stałym
system ogniw paliwowych
obliczeniowa dynamika płynów
metoda elementów skończonych
MES
modelowanie symulacje procesu
Opis:
The paper addresses the issues of quantification and understanding of Solid Oxide Fuel Cells (SOFC) based on numerical modelling carried out under four European, EU, research projects from the 7FP within the Fuel Cell and Hydrogen Joint Undertaking, FCH JU, activities. It is a short review of the main projects’ achievements. The goal was to develop numerical analyses at a single cell and stack level. This information was integrated into a system model that was capable of predicting fuel cell phenomena and their effect on the system behaviour. Numerical results were analysed and favourably compared to experimental results obtained from the project partners. At the single SOFC level, a static model of the SOFC cell was developed to calculate output voltage and current density as functions of fuel utilisation, operational pressure and temperature. At the stack level, by improving fuel cell configuration inside the stack and optimising the operation conditions, thermal stresses were decreased and the lifetime of fuel cell systems increased. At the system level, different layouts have been evaluated at the steady-state and by dynamic simulations. Results showed that increasing the operation temperature and pressure improves the overall performance, while changes of the inlet gas compositions improve fuel cell performance.
Źródło:
Chemical and Process Engineering; 2018, 39, 4; 377--393
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Usefulness of foundry tooling materials in microwave heating process
Możliwości zastosowania w procesie nagrzewania mikrofalowego materialów do budowy oprzyrządowania odlewniczego
Autorzy:
Granat, K.
Opyd, B
Nowak, D.
Stachowicz, M.
Jaworski, G.
Powiązania:
https://bibliotekanauki.pl/articles/355918.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
microwaves
permittivity
loss tangent
loss factor
foundry tooling
mikrofale
przenikalność
tangens kąta stratności
współczynnik stratności
oprzyrządowanie odlewnicze
Opis:
The paper describes preliminary examinations on establishing usefulness criteria of foundry tooling materials in the microwave heating technology. Presented are measurement results of permittivity and loss tangent that determine behaviour of the materials in electromagnetic field. The measurements were carried-out in a waveguide resonant cavity that permits precise determination the above-mentioned parameters by perturbation technique. Examined were five different materials designed for use in foundry tooling. Determined was the loss factor that permits evaluating usefulness of materials in microwave heating technology. It was demonstrated that the selected plastics meet the basic criterion that is transparency for electromagnetic radiation.
W pracy podjęto wstępne badania nad ustaleniem kryteriów oceny przydatności materiałów do budowy oprzyrządowania odlewniczego, przewidzianego do zastosowania w technologii nagrzewania mikrofalowego. Przedstawiono wyniki pomiarów przenikalności elektrycznej oraz tangensa kąta stratności, które określają zachowanie materiałów w polu elektromagnetycznym. Pomiary przeprowadzono na stanowisku falowodowej wnęki rezonansowej, która umożliwia precyzyjne wyznaczenie metodą perturbacyjną wymienionych parametrów. Badaniom poddano piec różnych materiałów przewidzianych do zastosowania w budowie oprzyrządowania odlewniczego. Określono współczynnik stratności, który pozwala, na ocenę przydatności materiałów w technologii nagrzewania mikrofalowego. Wykazano, że wybrane tworzywa sztuczne spełniają podstawowe kryterium, jakim jest transparentność dla promieniowania elektromagnetycznego.
Źródło:
Archives of Metallurgy and Materials; 2013, 58, 3; 919-922
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Morphology and elemental analysis of free range and stabled Polish Konik horses hair using Energy-dispersive X-ray spectroscopy (EDS)
Autorzy:
Kubiak, K.
Niedźwiedź, A.
Siwińska, N.
Jaworski, Z.
Żak, A.
Słowikowska, M.
Powiązania:
https://bibliotekanauki.pl/articles/2087781.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
diet
elemental composition
hair
horses
Polish Konik
shortages
Źródło:
Polish Journal of Veterinary Sciences; 2018, 21, 1; 65-72
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of serum cytokine levels in recurrent airway obstruction
Autorzy:
Niedzwiedz, A.
Borowicz, H.
Kubiak, K.
Nicpon, J.
Skrzypczak, P.
Jaworski, Z.
Cegielski, M.
Powiązania:
https://bibliotekanauki.pl/articles/31728.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
Recurrent airway obstruction (RAO) represents a serious health problem and is traditionally classified as an allergic disease, where contact with an antigen can induce clinical airway inflammation, bronchial hyper-responsiveness and reversible airway obstruction. Previous studies have demonstrated the presence of the Th2 response in the lungs of human patients with asthma and horses with heaves. These cells are involved in the production of cytokines which regulate the synthesis of immunoglobulins. 40 horses were evaluated: 30 horses with RAO and 10 healthy animals. The expression levels of interferon-alpha 1 (IFN-α1), interferon-gamma (IFN-γ), interleukin-1β, (IL-1β), IL-2, IL-4, IL-13 and tumor necrosis factor alpha (TNF-α) were measured in the serum obtained from control and RAO-susceptible horses during crisis. In all the patients, serum cytokine levels were detected. Serum median IL-13 and IFN-γ levels were significantly higher in RAO-affected horses than in the healthy group (p < 0.001). The serum median IFN-α1, IL-1β, IL-2, IL-4, and TNF-α levels were similar in both groups. These results indicate a low variability of the levels of cytokines and a high frequency of their detection in serum samples from horses with RAO. Immune mechanisms involved in equine RAO are more complex than those defined by a simple Th1/Th2 dichotomy.
Źródło:
Polish Journal of Veterinary Sciences; 2016, 19, 4
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-10 z 10

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