Skocz do pozycji: 1.

Tytuł:

Free vibration of clamped visco-elastic rectangular plate having bi-direction exponentially thickness variations

Autorzy:

Gupta, A. K.
Khanna, A.
Gupta, D. V.

Powiązania:

https://bibliotekanauki.pl/articles/281741.pdf

Data publikacji:

2009

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

viscoelasticity
clamped rectangular plate
variable thickness

Opis:

Free vibration of a clamped visco-elastic rectangular plate having bi-direction exponentially varying thickness has been analysed on the basis of classical plate theory. For visco-elastic materials, basic elastic and viscous elements are combined. We have assumed the Kelvin model for visco-elasticity, which is a combination of elastic and viscous elements connected in parallel. Here, the elastic element is constituted by a spring and the viscous one is a dashpot. An approximate but quite convenient frequency equation is derived by using the Rayleigh-Ritz technique. Logarithmic decrement, time period and deflection (at two different instant of time) for the first two modes of vibration and for various values of the taper constants and aspect ratio are calculated. Comparison studies have been carried out with bi-linearly thickness variation to establish the accuracy and versatility of the method.
W pracy rozważono problem swobodnych drgań utwierdzonej lepkosprężystej prostokątnej płyty o dwukierunkowo wykładniczo zmiennej grubości na podstawie klasycznej teorii płyt. Uwzględniono lepkosprężyste właściwości materiału płyty, bazując na podstawowych elementach reologicznych. Przyjęto model Kelvina, tj. równoległą kombinację elementu sprężystego i wiskotycznego. Równanie ruchu płyty rozwiązano metodą Rayleigha-Ritza, otrzymując przybliżoną, ale wygodną do analizy postać wyrażenia w dziedzinie częstości. Następnie wyznaczono wartość logarytmicznego dekrementu tłumienia, okresu drgań i ugięcia płyty dla dwóch pierwszych funkcji własnych dla różnych parametrów opisujących zmienną grubość i wymiary zewnętrzne płyty. Wyniki obliczeń przy uwzględnieniu zmiany grubości płyty porównano z dotychczasowymi rezultatami badań w celu potwierdzenia dokładności i uniwersalności metody.

Źródło:

Journal of Theoretical and Applied Mechanics; 2009, 47, 2; 457-471
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:

Siły wewnętrzne i reakcje podporowe w elementach obudowy prostokątnej
Internal forces and bearing reactions in units of rectangular support

Autorzy:

Rotkegel, M.

Powiązania:

https://bibliotekanauki.pl/articles/340383.pdf

Data publikacji:

2009

Wydawca:

Główny Instytut Górnictwa

Tematy:

obudowa prostokątna
podziałka obudowy prostokątnej
siły wewnętrzne obudowy
rectangular support
rectangular support pitch
internal forces in support

Opis:

W artykule przedstawiono metody obliczania podziałki obudowy prostokątnej. Uwzględniono obudowę prostokątną dwu-, trój- i czterostojakową. Wszystkie ostateczne wzory zostały sprowadzone do najprostszej postaci, co wpływa na skrócenie czasu obliczeń. Przy znanej wartości ciśnienia górotworu, dobór odpowiedniego rozstawu odrzwi zajmuje zaledwie kilka minut.
In the paper, method of calculation of rectangular support pitch was presented. Two, triple and four props rectangular support was considered. All final formulas were reduced to the simplest form, what impacts into the shortening of calculations time. At the known value of rockmass pressure, selection of suitable spacing of frames takes only a few minutes.

Źródło:

Prace Naukowe GIG. Górnictwo i Środowisko / Główny Instytut Górnictwa; 2009, 1; 51-66
1643-7608

Pojawia się w:

Prace Naukowe GIG. Górnictwo i Środowisko / Główny Instytut Górnictwa

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:

Calculations of the magnetic field of the three-phase 4-conductor line with rectangular busbars

Autorzy:

Kusiak, D.
Piątek, Z.
Szczegielniak, T.
Jabłoński, P.

Powiązania:

https://bibliotekanauki.pl/articles/1395763.pdf

Data publikacji:

2016

Wydawca:

Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej

Tematy:

magnetic field
rectangular busbar
high-current busduct

Opis:

The paper presents the results of the calculations of the magnetic field for the both shielded and non-shielded 3-phase MR 250 busbar manufactured by Elektromontaż 2 in Katowice, Poland. The busbar magnetic field has been determined by the following methods: analytical method for non–shielded busbar without taking into account the skin and proximity effects, analytical–numerical method based on integral equations, two-dimensional method of finite elements with the use of the commercial FEMM software, measurement method on a test stand. The measurements were performed with the use of a special non-directional magnetic field meter. A satisfactory compliance of the calculations has been obtained.

Źródło:

Computer Applications in Electrical Engineering; 2016, 14; 25-38
1508-4248

Pojawia się w:

Computer Applications in Electrical Engineering

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:

Analiza drgań płyty prostokątnej z naklejonymi elementami piezoelektrycznymi
Rectangular plate vibration analysis with bonded piezoelectric elements

Autorzy:

Szmidt, M.

Powiązania:

https://bibliotekanauki.pl/articles/213708.pdf

Data publikacji:

2008

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Lotnictwa

Tematy:

drgania płyty prostokątnej
elementy piezoelektryczne
rectangular plate vibration

Opis:

W pierwszych punktach pracy przeanalizowane są drgania aluminiowej prostokqtnej płyty, pobudzonej do drgń przez symulujące hałas lotniczy jednorodne ciśnienie akustyczne. Wykorzystana jest teoria plyt Kirchhoffa. Przyjęte jest podparcie przegubowe wszystkich brzegów płyty. Wychodząc od równania drgań płyty tworzone są kolejne, coraz bardziej złożone modele drgań uwzględniające wiskotyczne tłumienie w materiale płyty, a także wymuszenie kinematyczne na dwóch jej brzegach. Następnie zbadane są drgania jakie wzbudza naklejony na środku płyty prostokątny piezoaktuator pobudzany sinusoidalnie zmiennym napięciem. Do opisu obciążenia pochodzącego od piezoelementu wykorzystana jest teoria dystrybucji. Masa piezoelementu oraz wpływ warstwy kleju o skończonej sztywności na ścinanie są pominiete. Porównana jest zarówno postać drgań jak i wartość skuteczna prędkości drgań poprzecznych punktów płyty, pobudzanej ciśnieniem akustycznym oraz sterowanym piezoelementem. Zbadana jest także dynamika płyty z piezoaktuatorem wytrąconym ze stanu zerowych naprężeń, poprzez gwałtowne przyłożenie niezerowego napięcia. Do rozwiązania równań drgań wykorzystana jest metoda rozdzielenia zmiennych Fouriera. Przeprowadzane analizy pozwalają wysnuć wnioski co do słuszności koncepcji aktywnego tłumienia drgań poszycia kadłuba samolotu w celu obniżenia poziomu hałasu w kabinie. Niniejsza praca stanowi merytoryczny wstęp do projektu, mającego na celu opracowanie i realizację koncepcji aktywno-pasywnego tfumienia hałasu w kabinach niewielkich samolotów z napedem śmigłowym.
The vibration of a rectangular aluminium plate excited by the homogenous acoustic pressure simulating aircraft engine noise are studied. The Kirchhoff plate is assumed to be simply supported on all edges. Starting from the plate vibration equation, there are made more and more sophisticated plate vibration models considering viscous damping in the material and kinematic excitation on one pair of plate boundaries. Vibrations excited by sinusoidal voltage applied to piezoactuator bonded to the center of the plate are studied. Partial differential equation of plate motion is solved by means of the Fourier separation variable method. The piezoelement loading is written by means of a distributed theory. The piezoelement mass and the influence of a bonding layer with a finite shear stiffnes are neglected. The characteristics of the vibrations and the root mean square of a vibration velocity excited by acoustic pressure and controlled piezoelement are compared. The dynamics of the plate with the piezoactuator equilibrium disturbed by the rapidly applied voltage is examined. Obtained results lead to the conclusions reffering to the active damping of a fuselage skin plating vibrations concept of soundproofing. The paper is a preliminary work to the project of developing and realization of the active-passive internal noise muffling concept in the small propeller aircrafts.

Źródło:

Prace Instytutu Lotnictwa; 2008, 1(192); 1-57
0509-6669
2300-5408

Pojawia się w:

Prace Instytutu Lotnictwa

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:

Pre-designing of a mechatronic system using an analytical approach with Dymola

Autorzy:

Hamza, G.
Choley, J.-Y.
Hammadi, M.
Riviere, A.
Barkallah, M.
Louati, J.
Haddar, M.

Powiązania:

https://bibliotekanauki.pl/articles/281893.pdf

Data publikacji:

2015

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

pre-dimensioning
Dymola
analytical method
vibration
rectangular plate

Opis:

This paper presents a pre-dimensioning method applied to a mechatronic system and regarding the vibrational aspect, through a simple modeling process in Dymola environment. We study the vibration transmission between dynamic exciters (motors) and receivers (electronic cards) which are located on a simply supported rectangular plate, using an analytical approach. This new method will allow us to perform representative and robust modeling and simulation. The solution for this issue would be a pre-sizing and pre-positioning procedure. It aims to determine a set of possible technical solutions and principal characteristics before the definitive choice of components and precise sizing of the system. The presented method predicts also behaviour of the mechatronic system. In order to validate the model with respect to the finite element method, selected simulation results are presented.

Źródło:

Journal of Theoretical and Applied Mechanics; 2015, 53, 3; 697-710
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:

Changes of tourism in Croatia in the post-socialist period

Autorzy:

Wiskulski, Tomasz

Powiązania:

https://bibliotekanauki.pl/articles/1199408.pdf

Data publikacji:

2019-09-30

Wydawca:

Uniwersytet Gdański. Instytut Geografii

Tematy:

Croatia
Perkal Synthetic Indicator
Rectangular Coordinate System
tourism

Opis:

21 years of transformation in the tourist function in the territory of Croatia has been summarized in the article. This area has come a long way from the region that was an integral part of Yugoslavia, through the area of warfare related to the civil war to one of the fastest growing tourist destinations in the world. The number of tourists has more than tripled, with an increase from 57% to 1830% in individual counties of Croatia during the analyzed period. At the same time, there was a disproportionately low increase in capacity of accommodation base across the country at the level of 76%. This increase took values from 20% to 350% in extreme districts.

Źródło:

Journal of Geography, Politics and Society; 2019, 9, 3; 14-22
2084-0497
2451-2249

Pojawia się w:

Journal of Geography, Politics and Society

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:

Buckling analysis of three-layered rectangular plate with piezoelectric layers

Autorzy:

Yaghoobi, H.
Rajabi, I

Powiązania:

https://bibliotekanauki.pl/articles/282015.pdf

Data publikacji:

2013

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

three-layered rectangular plate
piezoelectric
critical buckling load

Opis:

This paper employs an analytical method to analyze the buckling of piezoelectric coupled plates with different boundary conditions on the basis of the first order shear deformation plate theory. The structure is composed of a host isotropic plate and two bonded piezo electric layers. Convergence study is performed in order to verify the numerical stability of the presented method. Also, the present analysis is validated by comparing the results with those in the literature, and then the critical buckling load of the piezoelectric coupled plates is presented in tabular and graphical forms for different plate aspect ratios, thickness of the piezoelectric, actuator voltage and boundary conditions.

Źródło:

Journal of Theoretical and Applied Mechanics; 2013, 51, 4; 813-826
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:

Parametric comparison of rectangular and circular pontoons performance as floating breakwater numerically

Autorzy:

Tabatabaei, S. M. R.
Zeraatgar, H.

Powiązania:

https://bibliotekanauki.pl/articles/260165.pdf

Data publikacji:

2018

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

Floating Breakwater
transmission coefficient
circular section
rectangular section

Opis:

Rectangular and circular pontoons are one of the most widely cross-sections used as floating breakwaters (FB). Although, there are several articles on comparison of behavior of rectangular and circular floating breakwaters however, the Authors try to show some details of difference between these two types where they have not been addressed before. To do so, transmission coefficient (Ct), as a measure of merit, of similar rectangular and circular sections is numerically compared. A computer code is developed for two-dimensional hydrodynamic analysis of floating breakwater based on diffraction theory in frequency domain in regular waves with any configuration of mooring line. The numerical method is the finite element method and validated by comparing with experimental and numerical results. Three types of rectangular sections are defined equivalent to circular section and a numerical comparison is made between 100 similar sections. The Ct versus wave frequency has been considered in detail and three new points called LMinF, LMaxF and LMaxCt are introduced. It has been shown that LMinF and LMaxF of circular section are greater and LMaxCt is much smaller than equivalent rectangular section. The LMaxCt of both sections are very dependent to new nondimensional parameter B/D (Breadth/Draft). Although, rectangular sections are more common for floating breakwater, however the results of this study show that possibility of using circular sections must be also considered.

Źródło:

Polish Maritime Research; 2018, S 1; 94-103
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:

Cullis-Radić determinant of a rectangular matrix which has a number of identical columns

Autorzy:

Makarewicz, Anna
Pikuta, Piotr

Powiązania:

https://bibliotekanauki.pl/articles/1395917.pdf

Data publikacji:

2020

Wydawca:

Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej

Tematy:

Determinant
rectangular matrix
Cullis-Radić determinant
repeated columns

Opis:

In this paper we present how identical columns affect the Cullis-Radić determinant of an \(m\times n\) matrix, where \(m\leq n\).

Źródło:

Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica; 2020, 74, 2
0365-1029
2083-7402

Pojawia się w:

Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:

Tunelowanie o przekroju prostokątnym
Rectangular tunnels construction

Autorzy:

Kuliczkowski, A.
Fujawa, M.

Powiązania:

https://bibliotekanauki.pl/articles/144166.pdf

Data publikacji:

2014

Wydawca:

Stowarzyszenie Inżynierów i Techników Komunikacji Rzeczpospolitej Polskiej

Tematy:

tunele
budowa
przekrój prostokątny
tunnels
construction
rectangular shape

Opis:

Przedstawiono metody budowy tuneli o przekroju prostokątnym. Skoncentrowano się na metodach bezwykopowych z uwagi na nieutrudnianie ruchu ulicznego. Przeanalizowano wybrane przykłady urządzeń tarczowych o przekrojach prostokątnych (wraz z kwadratowymi), a także zbliżonych do prostokątnych oraz zaprezentowano przykładowe realizacje tuneli z wykorzystaniem opisanych urządzeń.
The available no-dig methods of rectangular tunnels construction were presented. The authors focused on trenchless technologies as they do not disturb on ground traffic. Chosen examples of rectangular shield machines (including the square ones) as well as quasi rectangular ones were analyzed. The examples of tunnels built using described machines were also presented.

Źródło:

Drogownictwo; 2014, 7-8; 258-265
0012-6357

Pojawia się w:

Drogownictwo

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 11.

Tytuł:

Exponential temperature effect on frequencies of a rectangular plate of non-linear varying thickness: a quintic spline technique

Autorzy:

Gupta, A. K.
Mamta, J.

Powiązania:

https://bibliotekanauki.pl/articles/949230.pdf

Data publikacji:

2014

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

exponentially temperature
non-linear
thickness variation
vibration
rectangular plate

Opis:

The differential equation governing the transverse motion of an elastic rectangular plate of non-linear thickness variation with thermal gradient has been analyzed on the basis of classi- cal plate theory. Following Levy’s approach, i.e. the two parallel edges are simply supported, the fourth-order differential equation governing the motion of such plates of non-linear vary- ing thickness in one direction with exponentially temperature distribution has been solved by using the quintic splines interpolation technique for two different combinations of clamped and simply supported boundary conditions at the other two edges. An algorithm for com- puting the solution of this differential equation is presented for the case of equal intervals. The effect of thermal gradient together with taper constants on the natural frequencies of vibration is illustrated for the first three modes of vibration.

Źródło:

Journal of Theoretical and Applied Mechanics; 2014, 52, 1; 15-24
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 12.

Tytuł:

The rectangular two-phase closed thermosyphon: A case study of two-phase internal flow patterns behaviour for heat performance

Autorzy:

Chompookham, Teerapat
Sichamnan, Surachet
Bhuwakietkumjohn, Nipon
Parametthanuwat, Thanya

Powiązania:

https://bibliotekanauki.pl/articles/240618.pdf

Data publikacji:

2020

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

internal flow
flow pattern
rectangular two-phase closed thermosyphon

Opis:

This research explored different types of two-phase flow patterns that influenced heat transfer rate by assessing rectangular two-phase closed thermosyphon (RTPCT) made from glass with the sides of equal length of 25.2 mm, aspect ratio 5 and 20, evaporation temperature of 50, 70, and 90°C, working substance addition rate of 50% by volume of evaporator, and water inlet temperature at condensation of 20°C. Upon testing with aspect ratios 5, three flow patterns emerged which were: bubble flow, slug flow and churn flow respectively. As per the aspect ratio 20, four flow patterns were discovered which were: bubble flow, slug flow, churn flow and annular flow, respectively. Aspect ratio 5 pertains characteristic which resulted in a shorter evaporation rate of the RTPCT than that of the aspect ratio 20, thus, a shorter flow distance from the evaporator section to heat releaser was observed. Therefore, flow patterns at aspect ratio 5 exhibited a faster flow velocity than that of the aspect ratio 20. Furthermore, changes of flow pattern to the one that is important for heat transfer rate can be easily achieved. Churn flow was the most important type of the flow for heat transfer, followed by slug flow. Moreover, with aspect ratio 20, annular flow was the most important flow for the heat transfer, followed by churn flow, respectively. Throughout the test, average heat flux as obtained from the aspect ratio 5 were 1.51 and 0.74 kW/m2 which were higher than those of the aspect ratio 20. The highest heat flux at the operating temperature of the evaporator section was 90°C, which was equivalent to 2.60 and 1.52 kW/m2, respectively.

Źródło:

Archives of Thermodynamics; 2020, 41, 3; 223-254
1231-0956
2083-6023

Pojawia się w:

Archives of Thermodynamics

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 13.

Tytuł:

Inclination angle implications for fluid flow and mixed convection in complex geometry enclosure-meshless numerical analyses

Autorzy:

Najafi, M.
Nikfar, M.
Arefmanesh, A.

Powiązania:

https://bibliotekanauki.pl/articles/279898.pdf

Data publikacji:

2015

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

meshless
Petrov-Galerkin
mixed convection
rectangular cavity
wavy wall

Opis:

The meshless local Petrov-Galerkin (MLPG) method is extended to analyze the mixed convection and fluid flow in an inclined two-dimensional lid-driven cavity. The enclosure considered comprises two insulated vertical walls and a wavy bottom wall which is subjected to a higher constant temperature than its top counterpart, the sliding lid. For the proposed scheme, the stream function formulation with a weighting function of unity is employed. The simulation results reveal that the local Nusselt number increases with a clockwise increase in the inclination angle. Also, a decrease in the aspect ratio results in an increase in the hot wavy wall average Nusselt number.

Źródło:

Journal of Theoretical and Applied Mechanics; 2015, 53, 3; 519-530
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 14.

Tytuł:

Vibration frequencies of a rectangular plate with linear variation in thickness and circular variation in Poisson’s ratio

Autorzy:

Sharma, Amit

Powiązania:

https://bibliotekanauki.pl/articles/280855.pdf

Data publikacji:

2019

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

rectangular plate
circular variation
linear variation
Poisson’s ratio

Opis:

The frequency for the first two modes of vibration of a nonhomogeneous tapered rectangular plate is calculated under a bi linear (i.e., linear along both the axes) temperature field. For consideration of the nonhomogeneous material, the author assumed circular variation in Poisson’s ratio. Tapering in the plate is assumed to be linear in one direction. The results are calculated for different values of plate parameters and presented with the help of graphs. Comparison of the results is also given, to support the results of the present study.

Źródło:

Journal of Theoretical and Applied Mechanics; 2019, 57, 3; 605-615
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 15.

Tytuł:

Coloring rectangular blocks in 3-space

Autorzy:

Magnant, Colton
Martin, Daniel

Powiązania:

https://bibliotekanauki.pl/articles/743845.pdf

Data publikacji:

2011

Wydawca:

Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii

Tematy:

chromatic number
channel assignment problem
3 dimensional rectangular blocks

Opis:

If rooms in an office building are allowed to be any rectangular solid, how many colors does it take to paint any configuration of rooms so that no two rooms sharing a wall or ceiling/floor get the same color? In this work, we provide a new construction which shows this number can be arbitrarily large.

Źródło:

Discussiones Mathematicae Graph Theory; 2011, 31, 1; 161-170
2083-5892

Pojawia się w:

Discussiones Mathematicae Graph Theory

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 16.

Tytuł:

Free vibrational analysis of rectangular ducts with different joint conditions

Autorzy:

Jade, N.
Venkatesham, B.

Powiązania:

https://bibliotekanauki.pl/articles/279956.pdf

Data publikacji:

2018

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

rectangular duct
duct joint
experimental modal analysis
modal assurance criteria

Opis:

Rectangular ducts are fabricated using thin sheets of a metal with different joint conditions. Due to the presence of these joints, ducts deviate from their assumptive ideal shapes. The objective of the present work is to study the effect of different joint conditions and wall thickness on dynamic characteristics of the ducts. Experimental Modal Analysis (EMA) is performed on three rectangular ducts of different joint types. Numerical Modal Analysis (NMA) is also performed by considering that the ducts are of ideal rectangular shape (without joint condition). Correlation analysis is performed between EMA and NMA in terms of Modal Assurance Criteria (MAC), Relative Frequency Difference (RFD) plots and auto-MAC. It is observed that natural frequencies are in good agreement but there is a discrepancy in mode shapes.

Źródło:

Journal of Theoretical and Applied Mechanics; 2018, 56, 4; 1069-1081
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 17.

Tytuł:

Modelling method of dynamic characteristics of marine thin-walled structure

Autorzy:

Doan, Do Van
Szeleziński, Adam
Murawski, Lech
Muc, Adam

Powiązania:

https://bibliotekanauki.pl/articles/245078.pdf

Data publikacji:

2019

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

thin-walled structure
vibration
FEM
rectangular plate
Patran-Nastran software

Opis:

Thin-walled structures are very popular in industries, especially in the field of shipbuilding. There are many types of equipment and structures of ships, which are made up of thin-walled structures such as hull, deck and superstructure. Therefore, the analysis and understanding of the static and dynamic characteristics of a thin-walled structure are very important. In this article, we focus on vibration analysis of a typical thin-walled structurerectangular plate, a basic structure of the hull. Vibration analysis of a rectangular thin plate is conducted by two methods: numerical modelling method of the finite element on Patran-Nastran software platform and experimental method implemented in the laboratory of Gdynia Maritime University. Thin rectangular plate is fixed one end by four clamping plates and is modelled with finite elements and different meshing densities. The numerical model of thin rectangular plate is divided into four cases. Case 1, thin rectangular plate, and clamping plates are modelled with two-dimensional elements. Case 2, the rectangular thin plate is modelled with two-dimensional elements; the clamping plates are modelled with three-dimensional elements. Case 3, both the rectangular thin plate and clamping plates are modelled with three-dimensional elements. Case 4, the rectangular thin plate, and clamping plates are modelled with three-dimensional elements with larger mesh density to increase the accuracy of the calculation results. After that, the results of vibration analysis according to the numerical modelling method on Patran-Nastran software platform for these cases were compared with the measurement results. From there, assess the accuracy of analysis results of selected numerical model methods and the ability to widely apply this numerical model method to other marine structures

Źródło:

Journal of KONES; 2019, 26, 4; 39-46
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 18.

Tytuł:

An easy procedure to transform the ratio of two polynomials of first degree into Michaelis-Menten-type equations. Application to the ordered Uni Bi enzyme mechanism.

Autorzy:

Fontes, Rui
Ribeiro, João
Sillero, Antonio

Powiązania:

https://bibliotekanauki.pl/articles/1044439.pdf

Data publikacji:

2000

Wydawca:

Polskie Towarzystwo Biochemiczne

Tematy:

rectangular hyperbolas
enzyme inhibition
enzyme equations
enzyme kinetics
graphical presentations

Opis:

It is not always clear that some equations affected by complicated factors can, actually, be interpreted as a ratio of two polynomials of first degree and so that they can be, in general, represented by rectangular hyperbolas. In this paper we present an easy procedure to rearrange those equations into Michaelis-Menten-type equations and so to make the aspects of these rectangular hyperbolas more clear, particularly for researchers familiar with general biochemistry. As an example, the method is applied to transform the classical rate equation of the Cleland×s Ordered Uni Bi enzyme mechanism.

Źródło:

Acta Biochimica Polonica; 2000, 47, 1; 259-268
0001-527X

Pojawia się w:

Acta Biochimica Polonica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 19.

Tytuł:

Nierównomierność rozpływu mieszaniny dwufazowej gaz - ciecz w układzie minikanałów współpracujących równolegle
Two phase gas- liquid flow maldistribution in a system of parallel minichannels

Autorzy:

Miłaszewicz, B.
Ulbrich, R.

Powiązania:

https://bibliotekanauki.pl/articles/2071126.pdf

Data publikacji:

2010

Wydawca:

Stowarzyszenie Inżynierów i Techników Mechaników Polskich

Tematy:

minikanał prostokątny
równomierność przepływu
głowica
rectangular minichannel
flow uniformity
header

Opis:

Nierównomierna dystrybucja faz do poszczególnych kanałów jest powszechnym zjawiskiem i powoduje istotne obniżenie sprawności aparatów wykorzystujących przepływ w kanałach równoległych. Jest to zjawisko skomplikowane, słabo poznane w zakresie badań w minikanałach. W artykule przedstawiono badania przepływu opadającego mieszaniny dwufazowej do układu ośmiu minikanałów. Zastosowano dwa typy głowicy różniące się geometrią. Wykazano istotne znaczenie zarówno geometrii głowicy jak i strumieni doprowadzanych faz.
Phase maldistribution to particular channels is common phenomena and causes significant efficiency reduction of devices using parallel flow. It is very complicated and poorly examined phenomena in minichannels. Research results of two-phase downward flow of mixture to the system of eight parallel minichannels are presented in the paper. Two kinds of header of various geometry was employed. It was proved that both geometry and volumetric flow rate of gas and liquid had a substantial significance on flow uniformity.

Źródło:

Inżynieria i Aparatura Chemiczna; 2010, 3; 69-70
0368-0827

Pojawia się w:

Inżynieria i Aparatura Chemiczna

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 20.

Tytuł:

A modified Fourier-Ritz method for free vibration of rectangular plates with elastic constrains

Autorzy:

Wu, Tao
Chen, Zhao Bo
Qu, Jian Jun

Powiązania:

https://bibliotekanauki.pl/articles/2086961.pdf

Data publikacji:

2022

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

modified Fourier-Ritz method
rectangular plate
free vibration
boundary conditions

Opis:

In this paper, a modified Fourier-Ritz method is used to study free vibration of a rectangular plate with a set of simply supported opposite sides and another set of arbitrary elastic constraints. The influence of different elastic constraint stiffness values on the modal response of the rectangular plate is also analyzed. In order to avoid that the displacement function of the rectangular plate calculated by the traditional method and its derivative may be discontinuous or non-derivable at the boundary, the displacement function is expressed in the form of the sum of standard cosine series and a periodic polynomial function. Compared with the sine series expansion, the convergence of the result is enhanced. Several sets of numerical examples with different boundary conditions are given in the article, the data shows that the results calculated by this method have good accuracy and fast convergence. In addition, this paper also analyzes the boundary conditions and discusses the influence of different spring stiffness values on the setting of boundary conditions. The results can be applied to the setting of general boundary conditions and the study of vibration control of rectangular plates.

Źródło:

Journal of Theoretical and Applied Mechanics; 2022, 60, 1; 77--89
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 21.

Tytuł:

A Dual-band Circularly-polarized Printed Monopole Antenna for Wi-Fi and WiMAX Applications

Autorzy:

Lwin, Zaw Myo
Aye, Thae Su

Powiązania:

https://bibliotekanauki.pl/articles/307652.pdf

Data publikacji:

2019

Wydawca:

Instytut Łączności - Państwowy Instytut Badawczy

Tematy:

circular polarization
dual-band antenna
printed monopole antenna
rectangular slit

Opis:

This paper presents a rectangular-shaped printed monopole antenna with circular polarization for Wi-Fi (2.4–2.484 GHz) and WiMAX (3.3-3.7 GHz) bands. The antenna relies on asymmetric arrangement of the patch with respect to the microstrip feed, in order to generate circular polarization. Dual-band (Wi-Fi and WiMAX) operation is enabled by inserting a slit in the corner of the ground plane. Simulation results show a bandwidth increase of 15.9% (2.2–2.58 GHz) for Wi-Fi, and of 24.16% (3.13–3.99 GHz) for WiMAX applications. Furthermore, beamwidths at the axial ratio of 3 dB equal 48˚ and 51˚ for the x-z plane and y-z planes, respectively.

Źródło:

Journal of Telecommunications and Information Technology; 2019, 4; 50-54
1509-4553
1899-8852

Pojawia się w:

Journal of Telecommunications and Information Technology

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 22.

Tytuł:

Strength of a metal seven-layer rectangular plate with trapezoidal corrugated cores

Autorzy:

Magnucka-Blandzi, E.
Walczak, Z.
Wittenbeck, L.
Rodak, M.

Powiązania:

https://bibliotekanauki.pl/articles/280482.pdf

Data publikacji:

2017

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

rectangular layered plate
corrugated cores
hypothesis of deformation
deflection
stresses

Opis:

The subject of analytical and numerical investigations in this paper is a metal seven-layer rectangular plate with a trapezoidal corrugated main core and two trapezoidal corrugated cores of faces. The hypothesis of deformation of the normal to the middle surface of the plate after bending and field of displacements is formulated. The plate is simply supported on all its edges and subjected to a uniform pressure. Equations of equilibrium are derived based on the theorem of minimum total potential energy and are solved with the use of the Galerkin method. The influence of the trapezoidal corrugation pitch of the cores on the deflection and the equivalent stress is analysed.

Źródło:

Journal of Theoretical and Applied Mechanics; 2017, 55, 2; 433-446
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 23.

Tytuł:

Experimental tests for the occurence of convective heat transfer within the bed of rectangular steel profiles

Autorzy:

Wyczółkowski, R.
Musiał, D.

Powiązania:

https://bibliotekanauki.pl/articles/239990.pdf

Data publikacji:

2012

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

konwekcja swobodna
liczbia Rayleigha
free convection
Rayleigh number
rectangular sections

Opis:

The paper describes tests intended to examine the occurrence of natural convection within the space occupied by 40x20 mm rectangular steel sections. Within these tests the bed of four layers of section was heated by the electric palate heater. Depending on the manner in which the heater was positioned, the tests were divided into two series. In the case of heating from above, the heat flowing through the bed is transferred only by conduction and radiation. When heating the bed from below, in addition to conduction and radiation, also a convective heat transfer will occur. Should this be the case, it will result in the intensification of the heat exchange. The results of measurements carried out have not demonstrated that the occurrence of any possible natural convection would influence the development of a temperature field in this type of charge.

Źródło:

Archives of Thermodynamics; 2012, 33, 3; 89-100
1231-0956
2083-6023

Pojawia się w:

Archives of Thermodynamics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 24.

Tytuł:

Dynamic response analysis of a thin-walled rectangular plate subjected to thermoacoustic loadings

Autorzy:

Dang, Zhigao
Mao, Zhaoyong

Powiązania:

https://bibliotekanauki.pl/articles/240521.pdf

Data publikacji:

2020

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

thermoacoustic loadings
buckling
dynamic response
modal snap-through
rectangular plate

Opis:

For thin-walled structures invariably exposed to thermal and noise environment, their dynamic response is an extreme concern in the design of the component of advanced hypersonic aircraft. To address the problem, three theoretical models are established with three typical graded thermal distributions considered. By introducing the thermal moment, membrane forces and acoustic loadings into the vibration equation of plate, the governing equation is derived and it is solved combined with boundary conditions of the plate, the modal function and velocity compatibility equations at the fluid-structure coupling surface. The accuracy of the theoretical predictions is checked against finite element results with good agreement achieved. The results show that not the physical parameters with variation of temperature but the thermal moments and membrane forces, cause the buckling phenomenon. It is noted that buckling phenomenon occurs not only in uniform temperature field but also in graded temperature distribution filed. The mechanism analysis about modal snap-through and losing phenomenon indicates that thermoacoustic loadings will affect the stiffness matrix and mass matrix of structure. With the increase of temperature, the lower modes of the plate are lost, the higher modes appear in advance, and the losing phenomenon occurs in accordance with the order.

Źródło:

Archives of Thermodynamics; 2020, 41, 1; 151-174
1231-0956
2083-6023

Pojawia się w:

Archives of Thermodynamics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 25.

Tytuł:

Free vibration analysis of isotropic rectangular plates on Winkler foundation using differential transform method

Autorzy:

Kumar, Y.

Powiązania:

https://bibliotekanauki.pl/articles/265747.pdf

Data publikacji:

2013

Wydawca:

Uniwersytet Zielonogórski. Oficyna Wydawnicza

Tematy:

metoda transformacji
izotropia
differential transform method
isotropic
rectangular
Winkler foundation

Opis:

A differential transform method (DTM) is used to analyze free transverse vibrations of isotropic rectangular plates resting on a Winkler foundation. Two opposite edges of the plates are assumed to be simply supported. This semi-numerical-analytical technique converts the governing differential equation and boundary conditions into algebraic equations. Characteristic equations are obtained for three combinations of clamped, simply supported and free edge conditions on the other two edges, keeping one of them to be simply supported. Numerical results show the robustness and fast convergence of the method. Correctness of the results is shown by comparing with those obtained using other methods.

Źródło:

International Journal of Applied Mechanics and Engineering; 2013, 18, 2; 589-597
1734-4492
2353-9003

Pojawia się w:

International Journal of Applied Mechanics and Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 26.

Tytuł:

Behaviour of eccentrically inclined loaded rectangular foundation on reinforced sand

Autorzy:

Gupta, Sujata
Mital, Anupam

Powiązania:

https://bibliotekanauki.pl/articles/1845170.pdf

Data publikacji:

2021

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

eccentric loading
load inclination
ultimate bearing capacity
UBC
rectangular footing
geogrid

Opis:

This study presents the behaviour of model footing resting over unreinforced and reinforced sand bed under different loading conditions carried out experimentally. The parameters investigated in this study includes the number of reinforced layers (N = 0, 1, 2, 3, 4), embedment ratio (Df/B = 0, 0.5, 1.0), eccentric and inclined ratio (e/L, e/B = 0, 0.05, 0.10, 0.15) and (a = 0°, 7°, 14°). The test sand was reinforced with bi-axial geogrid (Bx20/20). The test results show that the ultimate bearing capacities decrease with axial eccentricity and inclination of applied loads. The test results also show that the depth of model footing increase zero to B (B = width of model footing), an increase of ultimate bearing capacity (UBC) approximated at 93%. Similarly, the multi-layered geogrid reinforced sand (N = 0 to 4) increases the UBC by about 75%. The bearing capacity ratio (BCR) of the model footing increases with an increasing load eccentricity to the core boundary of footing; if the load eccentricities increase continuity, the BCR decreases. The tilt of the model footing is increased by increasing the eccentricity and decreases with increasing the number of reinforcing layers.

Źródło:

Studia Geotechnica et Mechanica; 2021, 43, 2; 74-89
0137-6365
2083-831X

Pojawia się w:

Studia Geotechnica et Mechanica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 27.

Tytuł:

Influence of the shape of the explosive charge on blast profile

Autorzy:

Hryciów, Z.
Borkowski, W.
Rybak, P.
Wysocki, Z.

Powiązania:

https://bibliotekanauki.pl/articles/247727.pdf

Data publikacji:

2014

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

cylindrical and rectangular charge
blast overpressure
blast impulse
LS-DYNA
ALE

Opis:

When an explosive charge is fired, the nature and mass of the explosive are the only parameters of importance usually considered. The shape however, also plays a major role in the effect of an explosive charge. Knowledge of shape effect can be important before the use of the explosive (in order to create a maximum effect with a given mass of explosive), or in post-explosion damage assessment. The shape effect however is only significant within a certain range from the charge. At longer distance, the produced blast wave tends to be spherical. The shock wave parameters studied in this work are the peak overpressure and the first positive impulse. A series of numerical test has been performed in order to determine the range of influence of the charge shape. Different locations of initiation were compared. A hemispherical charge was point detonated at its centre whereas a cylindrical shape was detonated at the centre of an upper or lower plane. Numerical simulations of near field burst were conducted using LS-DYNA software. During numerical tests a pressure fields were determined for different shapes of explosive charges as well as the pressure waveforms at points located 1000 mm from a centre. Additionally, reference pressure history curves from LOAD_BLAST_ENHANCED procedure were calculated.

Źródło:

Journal of KONES; 2014, 21, 4; 169-176
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 28.

Tytuł:

Tensile fault dislocation in an irregular-layered elastic half-space

Autorzy:

Savita
Sahrawat, Ravinder Kumar
Malik, Meenal

Powiązania:

https://bibliotekanauki.pl/articles/2174174.pdf

Data publikacji:

2022

Wydawca:

Uniwersytet Zielonogórski. Oficyna Wydawnicza

Tematy:

odkształcenie
rozciąganie
naprężenie
deformation
tensile fault
layered half-space
rectangular irregularity

Opis:

In the present paper, an analytical solution for the static deformation of a two dimensional model consisting of an infinite homogeneous isotropic elastic layer of uniform thickness placed over an irregular isotropic elastic half-space due to movement of a long tensile fault has been obtained. The rectangular shaped irregularity is assumed to be present in the lower half-space and assuming that the fault lies in the elastic layer at a finite depth say ’h’ to the upper surface of the layer. For numerical computation, the expressions of displacements and stresses are calculated by using Sneddon’s method and the effect of source depth and irregularity on the displacements and stresses has been investigated graphically.

Źródło:

International Journal of Applied Mechanics and Engineering; 2022, 27, 3; 171--198
1734-4492
2353-9003

Pojawia się w:

International Journal of Applied Mechanics and Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 29.

Tytuł:

Modification of a test bench for testing torsional stiffness

Autorzy:

Macikowski, Krzysztof Ryszard

Powiązania:

https://bibliotekanauki.pl/articles/1179524.pdf

Data publikacji:

2017

Wydawca:

Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN

Tematy:

active stabilizer
modification
rectangular cross-section
test bench
torque issues
torsional stiffness

Opis:

Described modification concern a test bench for testing torsional stiffness. The bench was created to analyze behaviour a middle part of a new type of an active stabilizer. The middle part was was replaced by two or four profiles with rectangular cross-section which are constantly connected with not-changed parts of stabilizer (with its arms). Specially designed mechanism is responsible for changing stiffness and it performs it so that the profiles are expanded in the middle of sample on the same distance in opposite direction. An article contains brief description of mentioned test bench and one of a few issues which were revealed during investigations – weak accurancy of obtained results. It was determinated that modification in the area of the bench drive and change in recording system should allow on increase accuracy. After modifications became able to observe a phenomenon of changing torque behaviour, from linear to nonlinear, during twisting expanded sample.

Źródło:

World Scientific News; 2017, 76; 42-49
2392-2192

Pojawia się w:

World Scientific News

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 30.

Tytuł:

An Integrated Approach of Profi le Studies for Surface Water Velocity on a Steep Slope in a Rectangular Channel

Autorzy:

Ayalew, Abebe Temesgen
Koshuma, Abera Ermias
Ayele, Mesfi n Amaru
Dirate, Democracy Dilla

Powiązania:

https://bibliotekanauki.pl/articles/2181750.pdf

Data publikacji:

2022

Wydawca:

Stowarzyszenie Inżynierów i Techników Mechaników Polskich

Tematy:

fluid mechanics
velocity profiles
rectangular channel
Pitot tube
Acoustic Doppler Velocitymeter
ADV

Opis:

The flow velocity of water and its accurate surface profile estimation is important parameter as changes in climate increases the uneven rainfall patterns causing flood in downstream. It is important to know the velocity profile in steep open channel flows for solving the soil erosion, flooding and sediment transport problems in rivers or streams on steep slopes. A fixed bed laboratory experiment for a rectangular channel with steep slope is conducted to find the velocity profiles and surface profiles at different sections. Velocity profiles are presented at different sections in rectangular channel with steep slope. The outcome of the laboratory based experimental investigation shows that the velocity and surface profiles are influenced by the depth of flow of water and channel bed slope respectively.

Źródło:

Advances in Science and Technology. Research Journal; 2022, 16, 2; 74--80
2299-8624

Pojawia się w:

Advances in Science and Technology. Research Journal

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 31.

Tytuł:

Selected aspects of the design and construction of reinforced concrete sunk wells
Wybrane zagadnienia dotyczące projektowania i wykonywania żelbetowych studni opuszczanych

Autorzy:

Szymczak-Graczyk, A.

Powiązania:

https://bibliotekanauki.pl/articles/28765900.pdf

Data publikacji:

2022

Wydawca:

Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie

Tematy:

well
concrete well
sunk well
reinforced concrete
cutting edge
cylindrical tank
rectangular tank

Źródło:

Acta Scientiarum Polonorum. Architectura; 2022, 21, 3; 43-54
1644-0633

Pojawia się w:

Acta Scientiarum Polonorum. Architectura

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 32.

Tytuł:

A class of unbiased kernel estimates of a probability density function

Autorzy:

Rychlik, Tomasz

Powiązania:

https://bibliotekanauki.pl/articles/1340475.pdf

Data publikacji:

1995

Wydawca:

Polska Akademia Nauk. Instytut Matematyczny PAN

Tematy:

rectangular kernel
kernel function
randomized estimate
probability density function
nonparametric estimate
unbiased estimate

Opis:

We propose a class of unbiased and strongly consistent nonparametric kernel estimates of a probability density function, based on a random choice of the sample size and the kernel function. The expected sample size can be arbitrarily small and mild conditions on the local behavior of the density function are imposed.

Źródło:

Applicationes Mathematicae; 1993-1995, 22, 4; 485-497
1233-7234

Pojawia się w:

Applicationes Mathematicae

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 33.

Tytuł:

Analiza przepływu azotu w mikrokanale prostokątnym
Analysis of nitrogen flow in a rectangular microchannel

Autorzy:

Kopiczak, B.
Rup, K.

Powiązania:

https://bibliotekanauki.pl/articles/2071614.pdf

Data publikacji:

2011

Wydawca:

Stowarzyszenie Inżynierów i Techników Mechaników Polskich

Tematy:

mikrokanał prostokątny
poślizg na ściance
przepływ azotu
rectangular microchannel
wall slip
nitrogen flow

Opis:

W pracy dokonano analizy przepływu azotu w mikrokanalach o przekroju prostokątnym. Rozwiązanie ścisłe równania ruchu w mikrokanale wyrażono za pomocą podwójnego rozwinięcia w szereg Fouriera. W celach zastosowania wspomnianego rozwiązania wyznaczono, z układu dwóch równań na wartości własne, ich 50 kolejnych pierwiastków. Mając wyznaczone wartości własne pierwiastków, wyliczono wartości strumienia przepływu azotu w mikrokanale. Uzyskane wyniki porównano z odpowiednimi wynikami badań eksperymentalnych.
The paper presents an analysis of nitrogen flow in a microchannel with rectangular cross section. The exact solution of equations of motion in micro-channel was expressed by double expansion in Fourier series. For application purposes of these solutions, using the system of two equations for eigenvalues, their 50 following values were determined. Flow rate in the microchannel was calculated based on determined eigenvalues. The results were compared with the corresponding experimental results.

Źródło:

Inżynieria i Aparatura Chemiczna; 2011, 2; 7-10
0368-0827

Pojawia się w:

Inżynieria i Aparatura Chemiczna

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 34.

Tytuł:

Calculation for Acoustic Radiation Force from Rectangular Weakly Focusing Transducer Using the Ray Acoustic Model

Autorzy:

Yu, Lili
Qiao, Shuchang
Shou, Wende
Li, Junhua

Powiązania:

https://bibliotekanauki.pl/articles/2141691.pdf

Data publikacji:

2022

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

radiation force calculation
ray acoustic model
rectangular weakly focusing transducer
far-field integration

Opis:

Based on the ray acoustic model, a new relationship between the radiation force and the acoustic power is studied for a rectangular weakly focusing transducer. The effect of pressure reflection coefficient on this model is discussed. For a totally absorbing target, an approximate closed-form expression is also derived and the performance of this model is compared with that of the far-field integration model. The numerical results show that the agreement is excellent with these two models, which can be both used for correction of measured results, but the formula based on the ray acoustic model can be applied more widely in practice because of its simpler expression. The experimental results show further the effectiveness of the relationship between radiation force and acoustic power for rectangular weakly focusing transducer based on the ray acoustic model. The results presented in this paper are important for application of ultrasound transducers in therapy.

Źródło:

Archives of Acoustics; 2022, 47, 1; 81-88
0137-5075

Pojawia się w:

Archives of Acoustics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 35.

Tytuł:

The conditions for proper operation of the arch-rectangular support
Warunki poprawnej pracy odrzwiowej obudowy łukowo-prostokątnej

Autorzy:

Rotkegel, Marek

Powiązania:

https://bibliotekanauki.pl/articles/219613.pdf

Data publikacji:

2019

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

obudowa odrzwiowa
obudowa łukowo-prostokątna
analiza wytrzymałościowa
frame support
arch-rectangular support
strength analysis

Opis:

Steel arch-rectangular support has a wide range of applications in Polish coal mines due to its asym-metrical shape. The frame has an arched outline on one side of the side wall, while on the opposite side it is rectangular. As a result, the support is ideal for securing set up room and recovery room. It can also be successfully used to secure three-way intersections of underground workings. To a large extent, however, the importance of these advantages is diminished by relatively low load-bearing parameters, resulting from a partially straight canopy, as well as the asymmetrical distribution of the load acting on the support in underground conditions. In order to ensure the proper and optimal operation of such frames, in addition to the standard requirements for roof supports, additional conditions must be met. The basic requirement is to support the end of the canopy on the corner of the excavation. This article presents examples of arch-rectangular supports, their applications as well as laboratory tests and strength analysis of the frames and its elements. These tests allowed the requirements regarding the construction of the frame, the selection of the support and the conditions of building in the excavation to be specified.
Stalowa odrzwiowa obudowa łukowo-prostokątna znajduje w polskich kopalniach węgla kamiennego i ma szereg zastosowań, wynikających przede wszystkim z jej niesymetrycznego kształtu. Odrzwia po stronie jednego ociosu mają zarys łukowy, natomiast po stronie przeciwległego ociosu – prostokątny. Z tego względu idealnie nadają się do zabezpieczania rozcinek rozruchowych i kanałów likwidacyjnych ścian. Odrzwia powodzeniem mogą być także stosowane do zabezpieczania trójstronnych skrzyżowańwyrobisk korytarzowych. Jednak z znacznym stopniu wagę tych zalet pomniejszają niezbyt wysokie parametry podpornościowe, wynikające z częściowo prostoliniowej stropnicy, oraz niesymetryczny rozkład obciążenia działającego na odrzwia w warunkach dołowych. Dla zapewnienia właściwej i optymalnej pracy takich odrzwi oprócz standardowych wymagań dotyczących wykonywania obudo-wy konieczne jest spełnienie dodatkowych warunków. Podstawowym jest zapewnienie oparcia końca stropnicy o naroże wyrobiska. W artykule przedstawiono przykłady obudów łukowo-prostokątnych, ich zastosowania, a także badania stanowiskowe i analizę wytrzymałościową odrzwi i ich elementów. Badania te pozwoliły sprecyzowaćwymagania dotyczące konstrukcji odrzwi, doboru obudowy oraz zabudowy w wyrobisku.

Źródło:

Archives of Mining Sciences; 2019, 64, 1; 213-222
0860-7001

Pojawia się w:

Archives of Mining Sciences

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 36.

Tytuł:

Mathematical model of a leading line consisting of two pairs of beacons and its practical application

Autorzy:

Dzwonkowski, J.

Powiązania:

https://bibliotekanauki.pl/articles/906039.pdf

Data publikacji:

2015

Wydawca:

Akademia Morska w Szczecinie. Wydawnictwo AMSz

Tematy:

rectangular leading line
lateral deviation
waterway axis
Zalew Szczeciński waterway
waterway marking
mathematical modelling

Opis:

This paper presents a mathematical model of a leading line consisting of four beacons situated at the apexes of a rectangle. The ship handler compares angles between appropriate beacons to determine whether the vessel is in the middle of the fairway or not. This article assumes that the observer treats the two beacons on the front as a flat screen onto which rear beacons are projected. In this way he can estimate the quotients of sections created by appropriate beacons, from which he can find the lateral deviation from the waterway axis. This method of navigation is based on the Thales assertion. Described in detail, restrictions are the use of the model, precision assessment, and important in this respect, aspects of the waterway markings on Zalew Szczeciński.

Źródło:

Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2015, 44 (116); 109-115
1733-8670
2392-0378

Pojawia się w:

Zeszyty Naukowe Akademii Morskiej w Szczecinie

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 37.

Tytuł:

A study of flow boiling heat transfer in a rectangular minichannel using liquid crystal and infrared thermography

Autorzy:

Strąk, K.
Piasecka, M.

Powiązania:

https://bibliotekanauki.pl/articles/175560.pdf

Data publikacji:

2015

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

flow boiling heat transfer
rectangular minichannel
enhanced foil surface
liquid crystal thermography
infrared thermography

Opis:

This paper presents results of flow boiling heat transfer in two parallel asymmetrically heated vertical minichannels. The heating element for Fluorinert FC-72 flowing in the minichannels was a thin foil with an enhanced surface on the side in contact with the fluid. The channels were observed from both sides through glass panes. Two of the panes allowed us to observe the two phase flow patterns on the enhanced surface of the foil, while the other two panes were used for simultaneous measurement of temperature on the smooth side of the foil. The temperature was measured by applying two contactless methods. One was liquid crystal thermography (LCT), which required treating the foil surface with thermochromic liquid crystals (TLCs), and the other was infrared thermography (IRT), which required coating the foil surface with black paint. Calculations were performed on the basis ofa one-dimensional model to determine the heat transfer coefficient at the foil-fluid interface from the Robin boundary condition. The experimental results were graphically represented as the foil temperature and the heat transfer coefficient against the distance from the minichannel inlet and as LCT and IRT images obtained for saturated boiling.

Źródło:

Transactions of the Institute of Fluid-Flow Machinery; 2015, 128; 97-118
0079-3205

Pojawia się w:

Transactions of the Institute of Fluid-Flow Machinery

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 38.

Tytuł:

Numerical investigation of channel geometry on the performance of a PEM fuel cell

Autorzy:

Khazaee, I.
Mohammadiun, M.

Powiązania:

https://bibliotekanauki.pl/articles/264366.pdf

Data publikacji:

2013

Wydawca:

Uniwersytet Zielonogórski. Oficyna Wydawnicza

Tematy:

ogniwo paliwowe
modelowanie numeryczne
wydajność
PEM fuel cell
rectangular
triangular
elliptical
numerical modeling
performance

Opis:

A complete three-dimensional and single phase model for proton exchange membrane (PEM) fuel cells was used to investigate the effect of using different channels geometry on the performances, current density and gas concentration. The proposed model was a full cell model, which includes all the parts of the PEM fuel cell, flow channels, gas diffusion electrodes, catalyst layers and the membrane. Coupled transport and electrochemical kinetics equations were solved in a single domain; therefore no interfacial boundary condition was required at the internal boundaries between cell components. This computational fluid dynamics code was employed as the direct problem solver, which was used to simulate the three-dimensional mass, momentum, energy and species transport phenomena as well as the electron- and proton-transfer process taking place in a PEMFC. The results showed that the predicted polarization curves by using this model were in good agreement with the experimental results and a high performance was observed by using circle geometry for the channels of anode and cathode sides. Also, the results showed that the performance of the fuel cell improved when a rectangular channel was used.

Źródło:

International Journal of Applied Mechanics and Engineering; 2013, 18, 1; 85-98
1734-4492
2353-9003

Pojawia się w:

International Journal of Applied Mechanics and Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 39.

Tytuł:

Comparison beech wood tension strength parallel to grain of cylindrical samples with conical and funnel tapering versus standard rectangular cross section samples

Autorzy:

Karwat, Zbigniew
Koczan, Grzegorz
Rębkowski, Bartłomiej
Kozakiewicz, Paweł

Powiązania:

https://bibliotekanauki.pl/articles/2201354.pdf

Data publikacji:

2022

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Technologii Drewna

Tematy:

tension strength
cylindrical sample
conical shape
funnel shape
rectangular shape
turn-milling
beech Wood

Opis:

In this paper, the influence of shape samples on tension strength parallel to grain of beech wood have been analyzed. The cylindrical samples with conical tapering and with funnel tapering were used. Both types of cylindrical samples were compared with one-sided tapered standard samples with a rectangular cross-section. Experimental outcome indicates that cylindrical samples have higher tension strength than rectangular standard ones. Whereas shape of tapering in cylindrical samples (conical or funnel) was not statistically significant. Furthermore the presentation and reanalysis of data concerning use of cylindrical samples made of seven domestic wood species from the doctoral dissertation were performed. Comparison of that data with source data about tension strength of standard rectangular samples, have proven higher tension strength parallel to grain of cylindrical samples.

Źródło:

Drewno. Prace Naukowe. Doniesienia. Komunikaty; 2022, 65, 209; Art. no. 1644-3985.403.11
1644-3985

Pojawia się w:

Drewno. Prace Naukowe. Doniesienia. Komunikaty

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 40.

Tytuł:

Numerical study of ultimate bearing capacity of rectangular footing on layered sand

Autorzy:

Panwar, V.
Dutta, R. K.

Powiązania:

https://bibliotekanauki.pl/articles/952456.pdf

Data publikacji:

2020

Wydawca:

Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach

Tematy:

rectangular footing
finite element analysis
bearing capacity
layered sandstone
analiza elementów skończonych
nośność podłoża

Opis:

Purpose: The purpose of this study is to investigate the ultimate bearing capacity of the rectangular footing resting over layered sand using finite element method. Design/methodology/approach: Finite element analysis was used to investigate the dimensionless ultimate bearing capacity of the rectangular footing resting on a limited thickness of upper dense sand layer overlying limitless thickness of lower loose sand layer. The friction angle of the upper dense sand layer was varied from 41° to 46° whereas for the lower loose sand layer it was varied from 31° to 36°. Findings: The results reveal that the dimensionless ultimate bearing capacity was found to increase up to an H/W ratio of about 1.75 beyond which the increase was marginal. The results further reveal that the dimensionless ultimate bearing capacity was the maximum for the upper dense and lower loose sand friction angles of 46° and 36°, while it was the lowest for the upper dense and lower loose sands corresponding to the friction angle of 41° and 31°. For H/W = 0.5 and 2, the dimensionless bearing capacity decreases with the increase in the L/W ratio from 0.5 to 6 beyond which the dimensionless ultimate bearing capacity remains constant for all combinations of parameters. The results were presented in nondimensional manner and compared with the previous studies available in literature. Research limitations/implications: The analysis is performed using a ABAQUS 2017 software. The limitation of this study is that only finite element analysis is performed without conducting any experiments in the laboratory. Further the study is conducted only for the vertical loading. Practical implications: This proposed numerical study can be used to predict the ultimate bearing capacity of the rectangular footing resting on layered sand. Originality/value: The present study gives idea about the ultimate bearing capacity of rectangular footing when placed on layered sand (dense sand over loose sand) as well as the effect of thickness of top dense sand layer on the ultimate bearing capacity. The findings could be used to calculate the ultimate bearing capacity of the rectangular footing on layered sand.

Źródło:

Journal of Achievements in Materials and Manufacturing Engineering; 2020, 101, 1; 15-26
1734-8412

Pojawia się w:

Journal of Achievements in Materials and Manufacturing Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 41.

Tytuł:

Propagation in dielectric rectangular waveguides

Autorzy:

Yeap, K. H.
Teh, K. H.
Yeong, K. C.
Lai, K. C.
Loh, M. C.

Powiązania:

https://bibliotekanauki.pl/articles/173566.pdf

Data publikacji:

2016

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

dielectric rectangular waveguide
transverse wave numbers
attenuation coefficient
surface impedance
propagation constant
fundamental mode

Opis:

We present a fundamental and accurate approach to compute the attenuation of electromagnetic waves propagating in dielectric rectangular waveguides. The transverse wave numbers are first obtained as roots of a set of transcendental equations developed by matching the fields with the surface impedance of the wall. The propagation constant is found by substituting the values of transverse wave numbers into the dispersion relation. We have examined the validity of our model by comparing the computed results with those obtained from Marcatili’s equations and the finite element method. In our results, it is shown that the fundamental mode is identical with that found in a perfectly conducting waveguide. Our analysis also shows that a hollow waveguide is found to have much lower attenuation than its dielectric counterparts. Since the cutoff frequency is usually affected by the constitutive properties of the dielectric medium, for a waveguide designed for wave with the same cutoff frequency, hollow waveguides turn out to be relatively larger in size.

Źródło:

Optica Applicata; 2016, 46, 2; 317-330
0078-5466
1899-7015

Pojawia się w:

Optica Applicata

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 42.

Tytuł:

Analysis of air jets velocity attenuation at special initial conditions

Autorzy:

Voznyak, Orest
Spodyniuk, Nadiia
Savchenko, Olena
Dovbush, Oleksandr
Kasynets, Mariana
Datsko, Oleksandra

Powiązania:

https://bibliotekanauki.pl/articles/2146736.pdf

Data publikacji:

2022

Wydawca:

Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN

Tematy:

air distribution
swirl jet
rectangular jet
compact jet
flat jet
dystrybucja powietrza
strumień powietrza

Opis:

The article is devoted to solving the significant problem of efficiency increasing of air distribution in the premise by swirl air jet. The aim of the article is to decrease coefficient of velocity attenuation due to intensification of initial turbulence of different air streams leakage from the air distributor and to obtain of analytical equations for calculation of air distribution in a room to ensure the normative indoor air parameters. Effect of flow twisting results in a reduction of the velocity attenuation coefficient by 2.4 times. The regression analysis testified that the attenuation coefficient of the swirl air jet is more affected by the angle of the twisting plates inclination and less affected by the angle of change of the air flow direction. The attenuation coefficient of all types of rectangular air jets is more influenced by the the ratio of the sides of slit b/l and the angle of change of the air flow direction is also less affected. To minimize the attenuation factor, it is effective to use air distributors at smaller swivel plates inclination angles for swirl air jets and a smaller slit size ratio for all types of rectangular air jets.

Źródło:

Diagnostyka; 2022, 23, 3; art. no 2022308
1641-6414
2449-5220

Pojawia się w:

Diagnostyka

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 43.

Tytuł:

Impedancje własne i wzajemne szynoprzewodów prostokątnych o skończonej długości
Self and mutual impedances of rectangular bus-bars of finite length

Autorzy:

Szczegielniak, T.
Piątek, Z.
Kusiak, D.

Powiązania:

https://bibliotekanauki.pl/articles/408897.pdf

Data publikacji:

2014

Wydawca:

Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej

Tematy:

szynoprzewód prostokątny
tor wielkoprądowy
impedancja
metoda analityczna
rectangular busbar
high-current busduct
impedance
analytical method

Opis:

W artykule przedstawiono analityczną metodę obliczania impedancji układów szyn prostokątnych. Metoda ta oparta jest na teorii indukcyjności cząstkowych. W szczególności opisano impedancje szynoprzewodów prostokątnych w układzie trójfazowym z przewodem neutralnym. Wyznaczono rezystancje i reaktancje takiego wieloprzewodowego układu szynoprzewodów prostokątnych z uwzględnieniem zjawiska naskórkowości i zbliżenia. Przeprowadzono również pomiary impedancji ekranowanego toru wielkoprądowego o przewodach prostokątnych.
In this paper, a new numerical method of calculating rectangular busbar impedance is proposed. This method is based on integral equation method and partial inductance theory. Results for resistances and reactances for these systems of multiple rectangular conductors have been obtained. Skin and proximity effects have also been taken into consideration. The validation of the proposed method is carried out through FEM and laboratory measurements, and a reasonable level of accuracy is demonstrated.

Źródło:

Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska; 2014, 4; 21-24
2083-0157
2391-6761

Pojawia się w:

Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 44.

Tytuł:

Soil-structure-fluid interaction of the rectangular tank - seismic analysis
Interakcja grunt-konstrukcja-ciecz zbiornika prostokątnego - analiza sejsmiczna

Autorzy:

Kotrasová, K.

Powiązania:

https://bibliotekanauki.pl/articles/2067975.pdf

Data publikacji:

2017

Wydawca:

Politechnika Częstochowska

Tematy:

zbiornik prostokątny
płyn
trzęsienie ziemi
oddziaływanie płyn-struktura
rectangular tank
fluid
earthquake
fluid-structure interaction

Opis:

Ground-supported tanks are used to store a variety of liquids. The fluid develops hydrodynamic pressure on walls and bottom of tank during an earthquake. This paper provides theoretical background for specification of impulsive and convective actions of fluid in liquid storage rectangular container by using analytical methods. Numerical model of tank seismic response - the endlessly long shipping channel was obtained by using of Finite Element Method (FEM), Arbitrary-Lagrangian-Eulerian (ALE), Fluid Structure Interactions (FSI) formulation in software ADINA. The results of the analytical methods and the numerical solution were compared for partially water filled channel grounded on hard soil or sub-soil 30 MNm-3. It was considered the horizontal ground motion of the earthquake in Loma Prieta.
Zbiorniki naziemne są używane do przechowywania różnych płynów. Obecność płynu powoduje powstawanie ciśnienia hydrodynamicznego na ścianach i dnie zbiornika podczas trzęsienia ziemi. W artykule przedstawiono teoretyczne podstawy przy użyciu metod analitycznych dla określenia działań impulsywnych i konwekcyjnych płynu w prostokątnym pojemniku do magazynowania cieczy. Numeryczny model reakcji sejsmicznej zbiornika - nieskończenie długi kanał uzyskano, stosując metodę elementów skończonych (MES), równania Eulera-Lagrange’a, interakcję pomiędzy płynem i konstrukcją (FSI) w oprogramowaniu ADINA. Wyniki metod analitycznych i rozwiązania numerycznego porównano dla kanału częściowo wypełnionego wodą, uziemionego na twardej glebie lub podłożu 30 MNm-3. Analizowano ruch poziomy w trzęsieniu ziemi w Loma Prieta.

Źródło:

Zeszyty Naukowe Politechniki Częstochowskiej. Budownictwo; 2017, 23 (173); 147-156
0860-7214

Pojawia się w:

Zeszyty Naukowe Politechniki Częstochowskiej. Budownictwo

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 45.

Tytuł:

Study of the Outflow Conditions of the Weir Skoki on the Paklica River
Badanie warunków odpływu z jazu Skoki na rzece Paklica

Autorzy:

Walczak, Natalia
Hämmerling, Mateusz
Zawadzki, Paweł
Oliskiewicz-Krzywicka, Anna
Dąbrowski, Tomasz

Powiązania:

https://bibliotekanauki.pl/articles/1811979.pdf

Data publikacji:

2019

Wydawca:

Politechnika Koszalińska. Wydawnictwo Uczelniane

Tematy:

broad-crested rectangular weir
velocity
flow rate coeficient
przelew o szerokiej koronie
prędkości
współczynnik wydatku

Opis:

The paper presents an assessment analysis of the flow capacity of the barrage on the Paklica river. The analysed barrage consists of a mill weir and bottom outlets, and is supplied with water from Bukowiecki Lake. The reasons for addressing this subject matter were: from the need to determine the technical condition as well as the ecological condition of the lower position. The environmental status of the area below the system was considered as equally important. Field research included photographic documentation of the technical condition of the weir, taking into account the state below and above the structure, its abutments and the threshold. Additionally, there were made velocity distribution measurements in the downstream during the growing season, assuming this period as the least favourable with respect to hydraulic conditions.
W artykule oceniona została przepustowość stopnia wodnego na rzece Paklica. Analizowany stopień składa się z jazu młyńskiego i upustów dennych i jest zasilana wodą z jeziora Bukowieckiego. Przyczyny podjęcia tego tematu były następujące: potrzeba ustalenia stanu technicznego, a także stan ekologiczny analizowanego obiektu. Równie ważny był stan środowiskowy obszaru poniżej stopnia wodnego. W czasie badań terenowych wykonano dokumentację fotograficzną stanu technicznego jazu z uwzględnieniem stanu górnego i dolnego stanowiska, przyczółków oraz progu. Dodatkowo wykonano pomiary rozkładu prędkości w dolnym stanowisku w czasie wegetacji przyjmując ten okres za najmniej korzystny ze względów hydraulicznych.

Źródło:

Rocznik Ochrona Środowiska; 2019, Tom 21, cz. 2; 1489-1504
1506-218X

Pojawia się w:

Rocznik Ochrona Środowiska

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 46.

Tytuł:

A Power Transformer as a Source of Noise

Autorzy:

Zawieska, W. M.

Powiązania:

https://bibliotekanauki.pl/articles/90466.pdf

Data publikacji:

2007

Wydawca:

Centralny Instytut Ochrony Pracy

Tematy:

power transformer
noise reduction
active methods
transformer modeling
rectangular plate vibrations
transformer noise
vibroacoustic analysis

Opis:

This article presents selected results of analyses and simulations carried out as part of research performed at the Central Institute of Labor Protection – the National Research Institute (CIOP-PIB) in connection with the development of a system for active reduction of noise emitted by high power electricity transformers. This analysis covers the transformer as a source of noise as well as a mathematical description of the phenomenon of radiation of vibroacoustic energy through a transformer enclosure modeled as a vibrating rectangular plate. Also described is an acoustic model of the transformer in the form of an array of loudspeakers.

Źródło:

International Journal of Occupational Safety and Ergonomics; 2007, 13, 4; 381-389
1080-3548

Pojawia się w:

International Journal of Occupational Safety and Ergonomics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 47.

Tytuł:

Vibrational analysis of damped orthotropic rectangular plates with simple support on elastic Winkler foundation subjected to moving loads

Autorzy:

Idowu, A. S.
Are, E. B.
Gbadeyan, J. A.

Powiązania:

https://bibliotekanauki.pl/articles/264530.pdf

Data publikacji:

2017

Wydawca:

Uniwersytet Zielonogórski. Oficyna Wydawnicza

Tematy:

Winkler foundation
orthotropic rectangular plates
viscous damping
dynamic moving loads
płyta prostokątna
lepkość
obciążenie ruchome

Opis:

The model of a damped orthotropic rectangular plate resting on a Winkler foundation with a simple support has the fourth order differential equation governing it, which is reduced to a second order coupled differential equation by separating the variables. The coupled differential equation was solved using numerical schemes .The classical condition used as an illustrative example is the simple support condition. It is observed that damping plays a very significant role in the vibration of solid structures, as it has been shown that the deflection profile depends greatly on the damping ratio. The deflection profile also proves to be more stable in the presence of foundation coupled with viscous damping. The results obtained were discussed and graphically presented.

Źródło:

International Journal of Applied Mechanics and Engineering; 2017, 22, 4; 1075-1082
1734-4492
2353-9003

Pojawia się w:

International Journal of Applied Mechanics and Engineering

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 48.

Tytuł:

Inelastic stability analysis of uniaxially compressed flat rectangular isotropic CCSS plate

Autorzy:

Ibearugbulem, O. M.
Eziefula, U. G.
Onwuka, D. O.

Powiązania:

https://bibliotekanauki.pl/articles/265658.pdf

Data publikacji:

2015

Wydawca:

Uniwersytet Zielonogórski. Oficyna Wydawnicza

Tematy:

deflection function
plastic buckling
rectangular plate
Taylor's series
work principle
płyta izotropowa
wyboczenia
metoda Taylora

Opis:

This study investigates the inelastic stability of a thin flat rectangular isotropic plate subjected to uniform uniaxial compressive loads using Taylor-Maclaurin series formulated deflection function. The plate has clamped and simply supported edges in both characteristic directions (CCSS boundary conditions). The governing equation is derived using a deformation plasticity theory and a work principle. Values of the plate buckling coefficient are calculated for aspect ratios from 0.1 to 2.0 at intervals of 0.1. The results compared favourably with the elastic stability values and the percentage differences ranged from -0.353% to -7.427%. Therefore, the theoretical approach proposed in this study is recommended for the inelastic stability analysis of thin flat rectangular isotropic plates under uniform in-plane compression.

Źródło:

International Journal of Applied Mechanics and Engineering; 2015, 20, 3; 637-645
1734-4492
2353-9003

Pojawia się w:

International Journal of Applied Mechanics and Engineering

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 49.

Tytuł:

Al-Si and Al-Si-Mg Cast Alloys Shrinkage Porosity Estimation

Autorzy:

Samavedam, S.
Sundarrajan, S.

Powiązania:

https://bibliotekanauki.pl/articles/382288.pdf

Data publikacji:

2016

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

shrinkage characteristic
porosity
cast aluminium alloy
rectangular shape
process simulation
stop aluminium
porowatość
kształt
symulacja procesu

Opis:

US A356 and US 413 cast aluminium alloys shrinkage characteristic have been discussed in the present study. Specific volume reduction leads to shrinkage in castings and it can be envisaged as a casting defect. Finite difference based casting process simulation software has been used to study the shrinkage characteristic and it is quantified using mathematical formulae. The three dimensional model of the shrinkage defect has been constructed using CAD application software. Shrinkage characteristic has also been quantified through experimental validation studies and compared well with casting process simulation. Shrinkage characteristic study and control is essential for producing defect free castings. Influence of casting shape on the shrinkage characteristic has been studied in this paper.

Źródło:

Archives of Foundry Engineering; 2016, 16, 1; 61-68
1897-3310
2299-2944

Pojawia się w:

Archives of Foundry Engineering

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 50.

Tytuł:

Analytical 1D models of the wall thermal resistance of rectangular minichannels applied in heat exchangers

Autorzy:

Rybiński, W.
Mikielewicz, J.

Powiązania:

https://bibliotekanauki.pl/articles/240475.pdf

Data publikacji:

2016

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

minichannel heat exchanger
wall thermal resistance
rectangular minichannel
minikanał
wymiennik ciepła
izolacja termiczna ścian
minikanał prostokątny

Opis:

The paper presents four 1-dimensional models of thermal resistance of walls in a heat exchanger with rectangular minichannels. The first model is the simplest one, with a single wall separating two fluids. The second model of the so called equivalent wall takes into account total volume of intermediate walls between layers of minichannels and of side walls of minichannels. The next two more complicated models take separately into account thermal resistance of these walls. In these two models side walls are treated as fins. The results of models comparison are presented. It is shown that thermal resistance may be neglected for metal walls but it should be taken into account for the walls made of plastics. For the case of non-neglected wall thermal resistance the optimum wall thickness was derived. Minichannel heat exchangers made of plastic are larger than those built of metal, but are significantly cheaper. It makes possible to use of such exchangers in inexpensive microscale ORC installations.

Źródło:

Archives of Thermodynamics; 2016, 37, 3; 63-78
1231-0956
2083-6023

Pojawia się w:

Archives of Thermodynamics

Dostawca treści:

Biblioteka Nauki

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