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Wyświetlanie 1-15 z 729
Tytuł:
Significance of the receding contact angle in the determination of surface free energy
Autorzy:
Chodkowski, Michał Paweł
Powiązania:
https://bibliotekanauki.pl/articles/2079958.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
receding contact angle
equilibrium contact angle
Tadmor’s contact angle
CAH
surface free energy
Opis:
Surface free energy measurements of solids are a very important issue in various fields of science. Many functional, chemical and physical properties of a given material depend on its surface free energy. The basic method of the surface free energy determination are the contact angle measurements. There are several empirical methods useful to calculate the surface free energy of solids. They are based on the measurements of the contact angle of liquids with the defined surface tension. The aim of this paper is to examine the significance of the receding contact angle measurements in the determination of surface free energy of solids.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska, sectio AA – Chemia; 2018, 73, 1; 61-80
2083-358X
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska, sectio AA – Chemia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method for the estimation of sideslip angle for a vehicle equipped with a one-antenna GPS measuring system for steady state movement
Autorzy:
Pieniążek, Wiesław
Wolak, Stanisław
Janczur, Robert
Powiązania:
https://bibliotekanauki.pl/articles/263758.pdf
Data publikacji:
2019
Wydawca:
Sieć Badawcza Łukasiewicz. Przemysłowy Instytut Motoryzacji
Tematy:
sideslip angle
heading angle
yaw angle
yaw rate
GPS receiver signals
Opis:
One-antenna GPS systems present no possibility for the direct determination of vehicle slip angle. This is an easy task for dual antenna systems; however, many users have this kind of apparatus. In this paper, a method of estimation of this parameter, which is important for the estimation of vehicle steerability factors, is proposed (e.g. TB factor calculated on the basis of data from input test [8]). The method is based on two parameters measured by a one-antenna GPS system; these are the heading angle created from the Doppler channel coming directly from the GPS engine, and the yaw rate measured by an IMU device integrated and cooperating with the GPS engine. The sideslip angle which was calculated according to the proposed method is compared with an equivalent angle calculated on the basis of data from a non-slip measurement of velocity components for selected point of vehicle acquired using. The presented method is illustrated with examples from real tests. In the author’s opinion, the sideslip angle calculated with the application of measurement data obtained from a one-antenna GPS device could be used in practice. From comparison with another upper mentioned method, it follows that the differences between average values of sideslip angles obtained from both considered methods is not greater than 8%.
Źródło:
Archiwum Motoryzacji; 2019, 84, 2; 137-146
1234-754X
2084-476X
Pojawia się w:
Archiwum Motoryzacji
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An improved angle calibration method of a high-precision angle comparator
Autorzy:
Xia, Yangqiu
Wu, Zhilin
Huang, Ming
Liu, Xingbao
Mi, Liang
Tang, Qiang
Powiązania:
https://bibliotekanauki.pl/articles/1848955.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
angle calibration
position error
complete closure method
method verification
Opis:
Angle calibrations are widely used in various fields of science and technology, while in the high-precision angle calibrations, a complete closure method which is complex and time-consuming is common. Therefore, in order to improve the measurement efficiency and maintain the accuracy of the complete closure method, an improved calibration method was proposed and verified by the calibration of a high-precision angle comparator with sub-arc-second level. Firstly, a basic principle and algorithm of angle calibration based on complete closure and symmetry connection theory was studied. Then, depending on the pre-established calibration system, the comparator was respectively calibrated by two calibration methods. Finally, by comparing En values of two calibration results, the effectiveness of the improved method was verified. The calibration results show that the angle comparator has a stable angle position error of 0.17′′ and a measurement uncertainty of 0.05′′ (k=2). Through method comparisons, it was shown that the improved calibration method can greatly reduce calibration time and improve the calibration efficiency while ensuring the calibration accuracy, and with the decrease of measurement interval, the improvement of calibration efficiency was more obvious.
Źródło:
Metrology and Measurement Systems; 2021, 28, 1; 181-190
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A dynamic angle metrology system based on fibre-optic gyroscope and rotary table
Autorzy:
Chen, Lei
Zhou, Yilan
Zhang, Dengwei
Shu, Xiaowu
Liu, Cheng
Powiązania:
https://bibliotekanauki.pl/articles/220999.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
circular grating angle encoder
fibre-optic gyroscope
dynamic angle metrology
Opis:
Dynamic angle measurement (DAM) plays an important role in precision machining, aerospace, military and artificial intelligence. Because of its advantages including high sensitivity, solid state and miniaturization, fibre-optic gyroscope (FOG) has great application prospects in the field of DAM. In this paper, we propose a dynamic angle metrology method based on FOG and a rotary table to evaluate the DAM accuracy with FOG. The system synchronously collects data from the FOG and rotary table, and analyses the DAM accuracy of the FOG for different sway conditions compared with that of the angle obtained from the rotary table. An angle encoder in the rotary table provides absolute or incremental angular displacement output with angular displacement measurement accuracy of 10′′ (0:0028°) and angular displacement repeat positioning accuracy of 3′′ (0:00083°), and can be used as an angle reference. The experimental results show that the DAM accuracy of the FOG is better than 0:0028° obtained with the angular encoder, and the absolute DAM accuracy of the FOG is better than 0:0048° for given conditions. At the same time, for the multi-path signal synchronization problem in the metrology field, this paper proposes a signal delay measurement method combining test and algorithm procedures, which can control a delay within 25 μs.
Źródło:
Metrology and Measurement Systems; 2019, 26, 3; 497-504
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Deviation angle models in off-design high-pressure turbines
Autorzy:
Bugała, P.
Powiązania:
https://bibliotekanauki.pl/articles/247825.pdf
Data publikacji:
2018
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
turbomachinery
gas turbines
high-pressure turbine
HPT
deviation angle
Opis:
In the article, a set of deviation angle models, which are used to predict the off-design performance high-pressure turbines, has been presented, basing on a literature study. The deviation angle is a deviation between the actual flow angle and the blade inclination angle. It is an essential parameter in turbine performance evaluation. This angle shall be obtained accurately in 1-D design and evaluation, so as to ensure the validity of blade profiling and calculation results. If deviation angle is ignored, the turbine will produce a lower change of tangential velocity, and consequently a lower torque, output work and enthalpy drop than intended by the designer. For this reason, the deviation angle model needs to be established. There exist a number of different deviation models, resulting in varying degrees of flow deviation when applied. In the article, correlations for gas outlet angle, dependent on the Mach number at outlet and determined by the blade loading towards the trailing edge has been presented. The main difficulty in establishing the deviation model is a continuity in defining the angle for all speed ranges (both subcritical and supercritical). Each of the models presented in the article deals with this problem in a different way. A few deviation models, briefly discussed in the article, are based on experimental data and one is based on analytical approach.
Źródło:
Journal of KONES; 2018, 25, 2; 69-74
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New gyroplane hub connector with positive coning angle
Autorzy:
Wojtas, M.
Trendak, M.
Powiązania:
https://bibliotekanauki.pl/articles/244662.pdf
Data publikacji:
2017
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
blade dihedral angle
waving
rotor instability
teetering rotor
Opis:
The article presents advantages and disadvantages of two blade teetering rotors with constructional dihedral angle greater than 0o . Several structural design solutions of rotor hub connector are shown in this work. However, the main attention is focused on innovative hub connector design and manufactured by Trendak Aviation Company during the project “Research and development works on innovative construction of aircrafts of weight over 560 kilograms”. Discusses structural advantages of the new rotor hub connector according to other construction. Also were raised issues related to the load of the gyroplane rotor during the flight, in particular the load of rotor blades root, during a gyroplane break manoeuvre, according to conning angle of rotor hub connector. The disadvantages of using the structural dihedral angle in teetering rotors are also presented, focusing on the rotor aeroelastic instability so-called waving, which from the literature analysed is concerned only with two blades teetering rotors. Performed a coarse analysis in SMOG program, prepared at the Institute of Aviation for the analysis of helicopter and gyroplanes rotors. The stability analysis of the rotor for a number of structural dihedral angle and blades setting pitch was performed. Basis of this analysis the stability boundary were determined for the analysed gyroplane rotor with connector hub with positive coning angle of 2.8o. .
Źródło:
Journal of KONES; 2017, 24, 3; 325-330
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement of contact angle of copper-bearing shales using the captive bubble method
Autorzy:
Szyszka, D.
Powiązania:
https://bibliotekanauki.pl/articles/88887.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
contact angle
hydrophobicity
hydrophilicity
flotation
Opis:
This paper describes the measurement of contact angle of the natural surface of copper-bearing shales immersed in solutions of selected reagents of various concentrations using captive bubble method. It demonstrates that the copper-bearing shales coming from Legnicko-Głogwski Copper Region develop natural hydrophobic properties in surfactant (frother) solutions and its hydrophobicity decreases from 82⁰ contact angle in distilled water, 78⁰ in C4E1 solutions, 76⁰ in C4E2 solutions, to 75⁰ in dodecylphenol solutions. These data show that the addition of frother causes a decrease of shale hydrophobicity but it can reduce stability of the thin film between the grain and air bubble. It means that flotation of copper-bearing shales in the presence of frother will only be possible provided specific concentrations.
Źródło:
Mining Science; 2014, 21; 83-94
2300-9586
2353-5423
Pojawia się w:
Mining Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimum design of fiber angle and hole orientation of an orthotropic plate
Autorzy:
Zhang, X.
Lu, A.
Wang, S.
Zhang, N.
Powiązania:
https://bibliotekanauki.pl/articles/280011.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
orthotropic plate
fiber orientation angle
hole orientation angle
conformal transformation method
differential evolution algorithm
Opis:
With the goal of decreasing the stress concentration along the hole boundary in an orthotropic plate under inequi-biaxial loadings, an optimum design of the fiber angle and hole orientation is presented. The maximum absolute tangential stress along the hole boundary is taken as the objective function, and the fiber orientation angle and the hole orientation angle are considered as design variables. The conformal transformation method of a complex function and the Differential Evolution (DE) algorithm are used. Two non-circular shapes, ellipse and hexagon are taken as examples to analyze the problem. Based on the results, we can conclude that the major axis of elliptical holes should be designed in the direction of the maximum external loading for a perforated structure in an orthotropic plate. However, the principal direction that has the larger Young’s modulus should be inclined to the direction of the minimum loading, especially for a significantly orthotropic plate.
Źródło:
Journal of Theoretical and Applied Mechanics; 2018, 56, 1; 297-311
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of surface curvature on sessile droplet contact angle of nanofuids
Autorzy:
Cieśliński, J. T.
Krygier, K.
Powiązania:
https://bibliotekanauki.pl/articles/175339.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
contact angle
nanofluids
substrate curvature
Opis:
This paper deals with the change in contact angle of droplets for three nanofluids, i.e., water- Al2O3, water-TiO2 and water-Cu. Nanoparticles were tested at the concentration of 0.01, 0.1, and 1% by weight. Although dispersants were not used to stabilize the suspension, the solutions tested exhibited satisfactory stability. Ultrasonic vibration was used in order to stabilise the dispersion of the nanoparticles. Experimental measurements were performed for horizontal stainless steel (316) tube of three diameters, i.e., 1.6, 3 and 5 mm, and flat stainless steel plates. The results obtained show that the contact angle of tested nanofluids depends strongly on nanoparticle concentration as well as the curvature of the substrate.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2013, 125; 3-12
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tilt Angle of Wood Dust
Autorzy:
Ockajova, Alena
Banski, Adrian
Tomasz, Rogoziński
Powiązania:
https://bibliotekanauki.pl/articles/24072422.pdf
Data publikacji:
2023
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
wood dust
tilt angle
cleaning of dust
way of machining
Opis:
Tilt Angle of Wood Dust. The aim of this article is to point out a risk factor – wood dust, which settles on various structures, inclined surfaces in operation and, if not regularly cleaned, it is a source of secondary dust, because it is swirled up again with any movement. By measuring the tilt angle of bulk wood material obtained from sawing on a table circular saw, using different saw blades and wood dust from longitudinal and transverse sanding on a hand belt sander, we determined which characteristics affect it. We found that the size of the particles is an important characteristic, the larger they are, the smaller the tilt angle and also the surface of the pad on which the dust particles settle, wood did not play a significant role in this case. The smallest tilt angle was measured for sawdust from longitudinal sawing of 27°, and the largest tilt angle for wood dust from transverse sanding of oak and was 57° on beech pad.
Kąt nachylenia pyłu drzewnego. Celem tego artykułu jest zwrócenie uwagi na czynnik ryzyka - pył drzewny, który osadza się na różnych konstrukcjach, nachylonych powierzchniach podczas pracy. Jeśli nie jest regularnie usuwany, jest źródłem pyłu wtórnego, ponieważ jest ponownie zawirowywany przy każdym ruchu. Mierząc kąt pochylenia sypkiego materiału drzewnego uzyskanego z piłowania na stołowej pilarce tarczowej, przy użyciu różnych brzeszczotów i pyłu drzewnego ze szlifowania wzdłużnego i poprzecznego na ręcznej szlifierce taśmowej, ustaliliśmy, które cechy mają na to wpływ. Stwierdziliśmy, że rozmiar cząstek jest ważną cechą, im są one większe, tym mniejszy kąt pochylenia, a także powierzchnia podkładki, na której osadzają się cząstki pyłu, drewno nie odgrywało w tym przypadku znaczącej roli. Najmniejszy kąt pochylenia zmierzono dla trocin z piłowania wzdłużnego 27°, a największy kąt pochylenia dla pyłu drzewnego ze szlifowania poprzecznego dębu i wynosił 57° na podkładce bukowej.
Źródło:
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology; 2023, 121; 37--42
1898-5912
Pojawia się w:
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dokładność pomiaru kąta poziomego kamerą CCD
Accuracy of horizontal angle measurement performed with CCD camera
Autorzy:
Naus, K.
Wąż, M.
Powiązania:
https://bibliotekanauki.pl/articles/223186.pdf
Data publikacji:
2011
Wydawca:
Akademia Marynarki Wojennej. Wydział Dowodzenia i Operacji Morskich
Tematy:
nawigacja optoelektroniczna
pomiar kąta kamerą
dokładność pomiaru kąta
navigation optoelectronic
measuring angle with camera
angle measurement accuracy
Opis:
W artykule przedstawiono fragment opisu badań mających na celu ocenę możliwości zastosowania kamer CCD do określania pozycji statku w strefie przybrzeżnej. Skupiono się w nim wyłącznie na teoretycznej ocenie dokładności pomiaru kąta poziomego kamerą CCD. W pierwszej części artykułu opisano metodę obliczania rozdzielczości i błędu średniego pomiaru kąta poziomego między dwoma znakami nawigacyjnymi, zidentyfikowanymi na obrazie zarejestrowanym kamerą CCD. W części drugiej zaprezentowano wykresy rozdzielczości, błędu średniego i tzw. mapę dokładności (rozkładu błędu średniego) pomiaru kąta poziomego kamerą CCD wykonanego względem hipotetycznego układu dwóch znaków nawigacyjnych oraz analizę otrzymanych wyników. Część końcowa zawiera uogólnione wnioski wyprowadzone na podstawie przeprowadzonych badań.
This article presents part of description of the research on possibility to use CCD cameras to fix ship’s position in the coastal zone. It focuses exclusively on the theoretical measurement evaluation of accuracy of the horizontal angle with a CCD camera. The first part of the article describes the method for calculating resolution and a mean error of measurement of the horizontal angle between two navigation aids, identified in the image recorded with the CCD camera. The second part presents diagrams of resolution, a mean error and map accuracy (mean error distribution) of the horizontal angle measurement performed with the CCD camera. The measurement was made I relation to a hypothetical system of two navigation aids and an analysis of the results obtained. The final part contains a generalized conclusions based on the tests.
Źródło:
Zeszyty Naukowe Akademii Marynarki Wojennej; 2011, R. 52 nr 3 (186), 3 (186); 83-94
0860-889X
Pojawia się w:
Zeszyty Naukowe Akademii Marynarki Wojennej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhanced visibility of graphene: the effect of the Brewster angle
Autorzy:
Adamson, P.
Powiązania:
https://bibliotekanauki.pl/articles/173884.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
optical characterization
two-dimensional material
graphene
Brewster angle
differential reflectance
Opis:
Visibility and simple optical diagnostics possibilities of graphene layers on dielectric and semiconductor substrates at the Brewster angle are analyzed. The analysis is based on a numerical simulation. Several oxide semiconductors (ITO, ZnO, TiO2), weakly absorbing Si, and strongly absorbing GaAs are considered. It is shown that at the Brewster angle the optical contrast of graphene flakes on a bare semiconductor substrate is actually strong enough to see them under an optical microscope and there is really no need to create an additional interference film on the substrate.
Źródło:
Optica Applicata; 2017, 47, 3; 363-372
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of chitosan film surface structure on the contact angle
Autorzy:
Jagodzińska, Sylwia
Pałys, Beata
Wawro, Dariusz
Powiązania:
https://bibliotekanauki.pl/articles/2131497.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:
cellulose
chitosan
contact angle
films
microstructure
Opis:
The aim of this study was to evaluate the influence of the surface microstructure of chitosan films on the contact angle. Films without plasticising additives made of chitosan or regenerated chitosan were selected for the tests. A sessile drop method based on the European Pharmacopoeia was used to determine the contact angle. Due to the method of film production, the contact angle measurements were made on both the top and bottom surfaces of the film. For chitosan or regenerated chitosan films, the method of preparation slightly affected the difference in wettability between the top and bottom of the films, as confirmed by scanning electron microscopy. On the other hand, the wettability of the top and bottom of cellulose films varied greatly depending on the side of the film. Both chitosan and cellulose films had a homogeneous structure. There were differences in the microstructure between the top and the bottom of the sample in the cellulose film, a factor that affected the contact angle and thus the wettability of the surface.
Źródło:
Progress on Chemistry and Application of Chitin and its Derivatives; 2021, 26; 89-100
1896-5644
Pojawia się w:
Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Secondary flow structures and resultant exit flow angle fluctuations in high pressure steam turbine stage
Autorzy:
Świdryczuk, J.
Powiązania:
https://bibliotekanauki.pl/articles/1943184.pdf
Data publikacji:
2010
Wydawca:
Politechnika Gdańska
Tematy:
turbine stage
vortices
exit flow angle
Opis:
The object of investigation is the stage, the geometry and flow conditions of which are typical for a series of steam turbines in operation in Polish power plants. The flow analysis is based on the CFD calculations performed using FlowER, a specialized URANS code developed for studying unsteady phenomena in turbine stages and sections. The paper presents flow patterns illustrating the interaction between vortices inside and downstream of the rotor passage and the resultant exit flow angle (EFA) fluctuations recorded at the stage exit. An attempt is made to attribute individual EFA fluctuations to particular vortices and their development stages.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2010, 14, 1-2; 15-28
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On orthogonal projection of right angle
O niezmienniku charakterystycznym rzutowania prostokątnego
Autorzy:
Koźniewski, E.
Powiązania:
https://bibliotekanauki.pl/articles/118860.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Geometrii i Grafiki Inżynierskiej
Tematy:
invariant
orthogonal projection
right angle
inwariant
rzutowanie prostokątne
kąt prosty
Opis:
In some textbooks Descriptive Geometry characteristic invariant of orthogonal projection is used in the opposite sense than is formulated. The paper presents the complete formulation of the theorem and its simple proof suitable for presentation to students.
W niektórych podręcznikach geometrii wykreślnej niezmiennik charakterystyczny rzutowania prostokątnego jest stosowany w odwrotnym znaczeniu niż jest formułowany. W pracy przedstawiono pełne sformułowanie twierdzenia i jego prosty dowód, nadające się do zaprezentowania studentom.
Źródło:
Journal Biuletyn of Polish Society for Geometry and Engineering Graphics; 2015, 27; 29-31
1644-9363
Pojawia się w:
Journal Biuletyn of Polish Society for Geometry and Engineering Graphics
Dostawca treści:
Biblioteka Nauki
Artykuł
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