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Wyszukujesz frazę "similarity criteria" wg kryterium: Temat


Wyświetlanie 1-7 z 7
Tytuł:
Energy analysis of the propulsion shaft fatigue process in a rotating mechanical system part III dimensional analysis
Autorzy:
Korczewski, Zbigniew
Marszałkowski, Konrad
Powiązania:
https://bibliotekanauki.pl/articles/1573606.pdf
Data publikacji:
2021
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ship propulsion shaft
dimensional analysis
Buckingham theorems
similarity criteria
Opis:
This article presents the third and last part of the problem of diagnosing the fatigue of marine propulsion shafts in terms of energy with the use of the action function, undertaken by the authors. Even the most perfect physical models of real objects, observed under laboratory conditions and developed based on the results of their research, cannot be useful in diagnostics without properly transferring the obtained results to the scale of the real object. This paper presents the method of using dimensional analyses and the Buckingham theorem (the so-called π theorem) to determine the dimensionless numbers of the dynamic similarity of the physical model of the propulsion shaft and its real ship counterpart, which enable the transfer of the results of the research on the energy processes accompanying the ship propulsion shaft fatigue from the physical model to the real object.
Źródło:
Polish Maritime Research; 2021, 2; 72-77
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Method of Compact Ground Launching Devices Shape Formation for Unmanned Aerial Vehicles
Autorzy:
Sereda, Vladyslav A.
Ambrozhevich, Maya V.
Kornev, Aleksey V.
Powiązania:
https://bibliotekanauki.pl/articles/2073837.pdf
Data publikacji:
2022
Wydawca:
Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
Tematy:
shape formation
ground catapult
similarity criteria
mathematical model
performance optimization
Opis:
The purpose of this paper is to develop a method for forming the shape of compact ground launching devices (GLDs) unmanned aerial vehicles (UAVs), which includes three stages. Firstly, the choice on the basis of the theory of dimension and similarity of the closest analogue of the design object based on world experience gained in this field. Secondly, the creation of a comprehensive model of the working process of GLD and a universal method for its numerical implementation. Thirdly, the solution to the problem of optimizing the dynamic characteristics of GLD. At the described stages of the formation of the shape of an GLD UAV, a statistical analysis of the technical perfection of known analogues of UAV launch systems, methods of the theory of similarity and dimension in mechanics, methods of numerical simulation of the working process, and also methods of conditional parametric optimization are used. The undoubted importance of the problem of the equivalent development of the components of the UAS, consisting of an aircraft and a launch system (catapult). The traditionally non-priority status of GLD in the general cycle of the complex design program is also known. A systematic solution to this problem lies in the mainstream of creating common approaches, one of which is contained in this article. The proposed method of forming the appearance of compact GLDs UAV can be extended to a wide class of starting systems containing a thermal expansion machine and a mechanical component. In the presented form, the method is not applicable to systems of air, aerodrome and manual launch of UAVs. A method has been developed for the formation of the shape of GLD based on the energy relations of the criterion type between useful functions and the corresponding costs, with subsequent verification numerical studies of the launch processes based on specially created technology of a computational experiment, as well as optimization of the dynamic characteristics of GLD. The method of forming the shape of compact GLD is universally applicable to any type of catapults, regardless of the type of transmission and drive, since many particular forms of organization of the working process are generalized using the criteria of energy perfection, a comprehensive physical and mathematical model and normalization of the starting overload.
Źródło:
Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa; 2022, 13, 1 (47); 9--26
2081-5891
Pojawia się w:
Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stosunki sił i momentów sił jako kryteria podobieństwa dynamicznego różnych zjawisk występujących w inżynierii wiatrowej, inżynierii śniegowej i dynamice płynów. Część I – Podstawy i zagadnienia ustalone
Ratios of forces and forces moments as dynamic similarity criteria of various phenomena occurring in wind engineering, snow engineering and fl uid dynamics Part I – Fundamentals and steady problems
Autorzy:
Flaga, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/390641.pdf
Data publikacji:
2018
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
kryteria podobieństwa dynamicznego
inżynieria wiatrowa
inżynieria śniegowa
dynamika płynów
zagadnienia ustalone
dynamic similarity criteria
wind engineering
snow engineering
fluid dynamics
steady problems
Opis:
Praca dotyczy kryteriów podobieństwa dynamicznego różnych zjawisk występujących w inżynierii wiatrowej, inżynierii śniegowej i dynamice płynów wyprowadzonych ze stosunków sił i momentów sił wpływających na te zjawiska. Wyprowadzone i analizowane w części I kryteria podobieństwa dynamicznego dotyczą głównie następujących zagadnień ustalonych: 1. Przepływów i opływów płynów; 2. Zagadnień kontaktowych płyn – ciało stałe ; 3. Zagadnień pływania ciała stałego po płynie bez i z obecnością fal powierzchniowych.
The work concerns dynamic similarity criteria of various phenomena occurring in wind engineering, snow engineering and fl uid dynamics derived from ratios of forces and forces moments affecting these phenomena. Derived and analyzed in part I dynamic similarity criteria, mainly concern the following steady problems: 1. Fluid fl ows and fl ows past objects ; 2. Fluid-solid contact problems; 3. Problems of a solid fl oating on a fl uid with and without of the surface waves.
Źródło:
Budownictwo i Architektura; 2018, 17, 4; 121-140
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stosunki sił i momentów sił jako kryteria podobieństwa dynamicznego różnych zjawisk występujących w inżynierii wiatrowej, inżynierii śniegowej i dynamice płynów. Część II – Zagadnienia nieustalone o charakterze okresowym, quasi-okresowym lub turbulentnym
Ratios of forces and forces moments as dynamic similarity criteria of various phenomena occurring in wind engineering, snow engineering and fl uid dynamics Part I – Unsteady problems of periodic, quasi-periodic and turbulent character
Autorzy:
Flaga, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/391311.pdf
Data publikacji:
2018
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
kryteria podobieństwa dynamicznego
inżynieria wiatrowa
inżynieria śniegowa
dynamika płynów
zagadnienia ustalone
dynamic similarity criteria
wind engineering
snow engineering
fluid dynamics
steady problems
Opis:
Praca dotyczy kryteriów podobieństwa dynamicznego różnych zjawisk występujących w inżynierii wiatrowej, inżynierii śniegowej i dynamice płynów wyprowadzonych ze stosunków sił i momentów sił wpływających na te zjawiska. Wyprowadzone i analizowane w części II kryteria podobieństwa dynamicznego dotyczą głównie następujących zagadnień nieustalonych o charakterze okresowym, quasi-okresowym i turbulentnym: 1. Drgań ciała stałego w nieruchomym lub ruchomym płynie; 2. Odrywania się cząstek/płatków/klastrów śniegowych z wierzchniej warstwy złoża śniegu; 3. Wirujących turbin, śmigieł lub śrub okrętowych.
The work concerns dynamic similarity criteria of various phenomena occurring in wind engineering, snow engineering and fl uid dynamics derived from ratios of forces and forces moments affecting these phenomena. Derived and analyzed in part II dynamic similarity criteria, mainly concern the following unsteady problems of periodic, quasi-periodic and turbulent character: 1. Vibrations of a solid in a stationary and moving fl uid; 2. Snow particles/fl akes/clusters breaking off the outer layer of the snow deposit; 3. Rotating turbines, propellers or screw propellers.
Źródło:
Budownictwo i Architektura; 2018, 17, 4; 141-154
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Solution of Solid Charge Direct Resistance Heating with Similarity Theory
Autorzy:
Novák, P.
Janoščík, J.
Medved, D.
Powiązania:
https://bibliotekanauki.pl/articles/262620.pdf
Data publikacji:
2006
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Tematy:
direct resistance heating
conductive charge
electrocontact heating
temeperature and electromagetic fields
method of variable separation
method of final differences
criteria of similarity
Opis:
The place of generation of technologic heat is important applied criteria for classification of electric heating. According to that, the direct heating is if the heat is generated directly in the heated material, or the indirect heating if material is heated indirectly by the heat generated in conversion element. Possibilities of practical application of both methods are typical for resistant heating. Considering indirect heating, the charge is out of influence of electromagnetic field, this directly does not influence its temperature field. Temperature distribution in the charge volume depends only on its heat-physical properties and conditions of heat exchange on surface, i.e. thermo kinetic processes. Fourier's equation is applied in field solution. Considering direct heating, temperature distribution in the charge volume is more complicated. It is conditioned by interaction of temperature and electromagnetic field which is generated by the current flowing in the charge. Solution of temperature field in directly heated charge must for that reason respect current density distribution on its cross-section, this leads to applying of heat conduction equation. We introduce its application for different types of temperature fields in the solid charge in this article. We present solution by two methods, results are presented in criteria (no dimensional) form.
Źródło:
Electrical Power Quality and Utilisation. Journal; 2006, 12, 1; 9-15
1896-4672
Pojawia się w:
Electrical Power Quality and Utilisation. Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of binary data transformation in categorical data clustering
Autorzy:
Cibulková, Jana
Šulc, Zdenek
Sirota, Sergej
Rezanková, Hana
Powiązania:
https://bibliotekanauki.pl/articles/1194463.pdf
Data publikacji:
2019-07-02
Wydawca:
Główny Urząd Statystyczny
Tematy:
hierarchical cluster analysis
nominal variable
binary variable
categorical data
similarity measures
evaluation criteria
generated data
Opis:
This paper focuses on hierarchical clustering of categorical data and compares two approaches which can be used for this task. The first one, an extremely common approach, is to perform a binary transformation of the categorical variables into sets of dummy variables and then use the similarity measures suited for binary data. These similarity measures are well examined, and they occur in both commercial and non-commercial software. However, a binary transformation can possibly cause a loss of information in the data or decrease the speed of the computations. The second approach uses similarity measures developed for the categorical data. But these measures are not so well examined as the binary ones and they are not implemented in commercial software. The comparison of these two approaches is performed on generated data sets with categorical variables and the evaluation is done using both the internal and the external evaluation criteria. The purpose of this paper is to show that the binary transformation is not necessary in the process of clustering categorical data since the second approach leads to at least comparably good clustering results as the first approach.
Źródło:
Statistics in Transition new series; 2019, 20, 2; 33-47
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Decision-Making Process Development for Industry 4.0 Transformation
Autorzy:
Sajjad, Ahmad
Ahmad, Wasim
Hussain, Sulman
Powiązania:
https://bibliotekanauki.pl/articles/2201777.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
analytical hierarchy process
AHP
technique for order of preference by similarity to ideal solution
TOPSIS
operational flexibility
Industry 4.0
multi-criteria decision making
MCDM
Opis:
Development of design characteristics based dynamic decision support framework is presented in the current study, to facilitate the decision makers in the transformation of system in the industry 4.0 paradigm. The model development is designed for a robust decision-making approach to integrating human and machine knowledge to adopt smart technologies and system design. The system is based on prioritization of the industry 4.0 design principles and characteristics including flexibility, self-adaptability, self-reconfigurability, context awareness, decision autonomy, and real-time capabilities. It has been revealed from an industrial field study, the companies facing difficulty to transform the system, and systematics approach needed to overcome the challenge. A decision support process has been developed as an integrated approach to embedding human knowledge. The developed process has been validated using Technique for Order of Preference by Similarity to Ideal Solution, the results depict the operational flexibility, has been most crucial transformation characteristics prioritized using the Analytical Hierarchical Process. The developed process has the capability to help the system development and estimate the factors involved in the transformation.
Źródło:
Advances in Science and Technology. Research Journal; 2022, 16, 3; 1--11
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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