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Wyświetlanie 1-7 z 7
Tytuł:
Experimental investigation for non-linear vibrations of free supported and cantilever FFF rectangular plates
Autorzy:
Abdeddine, E.
Majid, A.
Beidouri, Z.
Zarbane, Kh.
Powiązania:
https://bibliotekanauki.pl/articles/24200580.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
fused filament
nonlinear dynamic behaviour
nonlinear transverse vibrations
nieliniowe zachowanie dynamiczne
nieliniowe drgania poprzeczne
Opis:
Purpose: The aim of this paper is to investigate experimentally the effect of large vibration of a cantilever and a fully free rectangular plate made by a Fused Filament Fabrication process. Furthermore, this investigation attempts to compare our measurements and those obtained in the literature experimentally. Design/methodology/approach: For this purpose, a test rig was designed and manufactured for all experimental trials. The plate was excited randomly and harmonically at large displacement respectively, to obtain the linear and non-linear frequencies parameter. Findings: The non-linear dynamic behaviour of our structure at forced vibration is figured by exciting the plate at large displacement. The dependence of frequency and amplitude vibration are examined for the first, second, and third mode shapes. The non-linear dynamic behaviour of cantilever plates is compared with literature to illustrate the convergence of our results by using our specific mechanical properties, printing parameters, and process. Furthermore, the non-dimensional comparison is shown by 33.38%, 5.83%, and 20.58% for the first, second, and third mode shapes, respectively. Research limitations/implications: Experimental tests will be performed on a 3D-printed metal plate to improve the present work. Practical implications: This work is intended to determine the dynamic proprieties of our parts in order to manufacture a safe and comfort machine. Originality/value: Actually, the dynamic behaviour of our 3D printing plates is compared with the obtained in the case of the isotropic plate for the aim to predict the convergence of both structures.
Źródło:
Archives of Materials Science and Engineering; 2022, 116, 2; 49--56
1897-2764
Pojawia się w:
Archives of Materials Science and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical investigation of geometrically nonlinear clamped uniform rods and rods with sections varying exponentially free vibration
Autorzy:
Abdeddine, E.
Majid, A.
Bouzida, N.
Bouzida, Z.
Zarbane, Kh.
Powiązania:
https://bibliotekanauki.pl/articles/2201031.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
non-linear longitudinal vibration
Lagrange equations
harmonic balance method
linearized approach
drgania nieliniowe
drgania podłużne
równania Lagrange'a
metoda bilansu harmonicznych
podejście linearne
Opis:
Purpose: The present paper is intended to investigate the problem of linear and non-linear longitudinal free vibration of uniform rods and rods whose cross-sections vary exponentially at large vibration amplitudes. Design/methodology/approach: The method adopted consists in discretizing the energy term on linear kij and non-linear rigidity tensor bijkl, as well as the mass tensor mij. Therefore, the formulation of this structure is based on Lagrange equations and the harmonic balance method so as to obtain the nonlinear algebraic equations. These latter are solved numerically and analytically through the explicit and linearized method. Findings: The response of Clamped-Clamped uniform and non-uniform rods on our structure are highlighted in the amplitude frequency and associated first three mode shapes. Moreover, this research leads to study the influence of the exponential slope on the maximum displacement, thus emphasizing the non-uniform bars usefulness. The obtained results are then compared with the available literature with a view to validating this theory. Research limitations/implications: As a perspective, the method used in this paper would be pushed to study the FDM material, taking into account other parameters related to additive manufacturing, and later to be validated experimentally. Practical implications: Longitudinal vibrations are important in mechanical structures; therefore, the determination of their dynamic behaviour needs to be understood. In the present study, the effect of the displacement amplitude on the exponential slope of the structure was analysed, which led to the determination of the reduction range of the vibration amplitude under resonance. However, this should be taken into account in the design process. Besides, the usefulness of the non-linearity geometric effects was demonstrated to examine these structures by considering all the parameters involved. Originality/value: A linearized procedure is used to solve a nonlinear algebra equation. The use of this method leads to reduce calculation time contrary to iterative methods.
Źródło:
Journal of Achievements in Materials and Manufacturing Engineering; 2022, 112, 2; 49--63
1734-8412
Pojawia się w:
Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Discourse-Pragmatic and Processing-Related Motivators of the ordering of Reason Clauses in an Academic Corpus
Autorzy:
Rezaee, Abbas A
Nemati, Majid
Golparvar, Seyyed Ehsan
Powiązania:
https://bibliotekanauki.pl/articles/620538.pdf
Data publikacji:
2018-11-16
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
positioning
reason clauses
subordinator
bridging
vomplexity
Opis:
The present research is aimed at examining the relative importance of the competing motivators of the sequencing of reason clauses in a corpus of research articles of applied linguistics. All the finite reason clauses accompanied by their main clauses in this corpus were collected. Random forest of conditional inference trees is the statistical modelling in this study. The findings showed that sentence-final reason clauses outnumber sentenceinitial ones. Moreover, subordinator choice and bridging, which are discourse-pragmatic constraints on clause positioning, emerged as the two more powerful predictors of the ordering of reason clauses in this corpus. Furthermore, the complexity of the clause turned out to be a stronger processing-related predictor than the length of the clause.
Źródło:
Research in Language; 2018, 16, 3
1731-7533
Pojawia się w:
Research in Language
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Classification of Cactus Graphs According to their Domination Number
Autorzy:
Hajian, Majid
Henning, Michael A.
Rad, Nader Jafari
Powiązania:
https://bibliotekanauki.pl/articles/32315639.pdf
Data publikacji:
2022-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
domination number
lower bounds
cycles
cactus graphs
Opis:
A set S of vertices in a graph G is a dominating set of G if every vertex not in S is adjacent to some vertex in S. The domination number, γ(G), of G is the minimum cardinality of a dominating set of G. The authors proved in [A new lower bound on the domination number of a graph, J. Comb. Optim. 38 (2019) 721–738] that if G is a connected graph of order n ≥ 2 with k ≥ 0 cycles and ℓ leaves, then γ(G) ≥ ⌈(n − ℓ + 2 − 2k)/3⌉. As a consequence of the above bound, γ(G) = (n − ℓ + 2(1 − k) + m)/3 for some integer m ≥ 0. In this paper, we characterize the class of cactus graphs achieving equality here, thereby providing a classification of all cactus graphs according to their domination number.
Źródło:
Discussiones Mathematicae Graph Theory; 2022, 42, 2; 613-626
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Process optimization of nickel extraction from hazardous waste
Autorzy:
Gharabaghi, M.
Irannajad, M.
Azadmehr, A. R.
Majid, E.
Powiązania:
https://bibliotekanauki.pl/articles/204554.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
factorial design
hazardous waste
nickel extraction
optimization
Opis:
Zinc plant residue is a hazardous waste which contains high quantity of nickel and other valuable metals. Process parameters such as reaction time, acid concentration, solid-liquid ratio, particle size, stirring speed and temperature for nickel extraction from this waste were optimized using factorial design. Main effects and their interactions were obtained by the analysis of variance ANOVA. Empirical regression model was obtained and used to predict nickel extraction with satisfactory results and to describe the relationship between the predicted results and the experiment results. The important parameters for maximizing nickel extraction were identifi ed to be a leaching time solid-liquid ratio and acid concentration. It was found that above 90% of nickel could be extracted in optimum conditions
Źródło:
Archives of Environmental Protection; 2012, 38, 3; 29-40
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation on the structural, optical and topographical behavior of Cadmium oxide polycrystalline thin films using electrochemical depositing method at different times
Autorzy:
Abd, Ahmed N.
Dawood, Mohammed O.
Hassoni, Majid H.
Hussein, Ali A.
Powiązania:
https://bibliotekanauki.pl/articles/1192094.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Cadmium oxide
thin film
optical characteristics of film
electrochemical depositing method
Opis:
The optical and structure properties of Cadmium oxide (CdO) thin film prepared by electrochemical deposition method at different times (15, 30 and 60) min were investigated in this paper. Results of optical Transmission, absorption, reflection spectra, optical conductance, refractive index, extension coefficient, real and imaginary dielectric constants studies are reported. The optical transmittance of the CdO thin film which formed at room temperature was 20% at wavelength ≈350 nm then increases to 60% at wavelength ≈1100 nm for thin film of CdO. The band-gap was also calculated from the equation relating absorption coefficient with the wavelength. The energy band gap changes from 2.3eV (Bulk CdO) to 2.45eV (CdO thin film). The plotted graphs show the optical characteristics of the film which varied with the wavelength and the photon energy. The optical conductance and band-gap indicated that the film is transmitting within the visible range. The dielectric constant and optical conductance of the film initially decreases slowly with increase in photon energy. The extinction coefficient and refractive index of the films also evaluated, which affected with the change in transmittance. The structure of synthesised CdO thin film was analyzed by X-ray diffraction XRD which revealed that the CdO thin film are polycrystalline and have several peaks of cubic face structure. The crystallite size, dislocation density, microstrain and number of dislocations of the thin film were calculated and listed.
Źródło:
World Scientific News; 2016, 37; 249-264
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluating the Total Phenolic, Protein Contents, Antioxidant and Pharmacological Effects of Cynodon dactylon Extracts Against Escherichia coli and Staphylococcus aureus
Autorzy:
Ibrahim, Muhammad
Riaz, Moazama
Ali, Akbar
Shaheen, Musarat
ur Rahman, Shafiq
Aziz, Riffat
Alamri, Abdulhakeem S.
Alhomrani, Majid
Dablool, Anas S.
Alghamdi, Saad
Sameeh, Manal Y.
Tashkandi, Manal A.
Powiązania:
https://bibliotekanauki.pl/articles/27315658.pdf
Data publikacji:
2023
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Cynodon dactylon
Anti-microbial
Flavonoids
Total Soluble Proteins
Peroxidase
Antioxidant
Super oxide Dismutase
Opis:
The study was aimed to characterize the antioxidant and anti-microbial activities of Cynodon dactylon with special reference on its precise biochemical analysis. Physiological analysis that total carotenoids content (0.3884 ± 0.0172 mg/g), total chlorophyll content (6.1460 ± 0.2915 mg/g), total phenolic contents (13.4703 ± 0.1494 mg/g), chlorophyll a (3.7708 ± 0.1528 mg/g, catalase (CAT) contents (40.2844 ± 0.1515 units/ mg), total anthocyanin contents (5.0166 ± 0.2966 g–1 FW) total soluble proteins (2.9916 ± 0.1734 mg/g) and total flavonoids content (TFC) (4.7863 ± 0.0442 μg/g) was found higher in the leaves of the Cynodon dactylon whereas, chlorophyll b (2.4881 ± 0.1326 mg/g) was found higher in the stem of Cynodon dactylon, while, peroxidase (POD) contents (81.8763 ± 4.6609 units/mg) and superoxidase dismutase (SOD) activity (80.4346 ± 5.9367 units/mg) was investigated higher in roots of Cynodon dactylon. The anti-microbial activity of Cynodon dactylon extracts was performed using a good diffusion technique against two microbial strains. Among all the plant extracts, the methanolic extracts showed a maximum inhibition zone (26.87 mm) against anti-bacterial strain Escherichia coli whereas n-hexane extract showed a maximum inhibition zone (17.88 mm) against anti-fungal strain Candida albicans. This study reported the antimicrobial activity of Cynodon dactylon against some common pathogens such as Staphylococcus aureus, Escherichia coli, and Candida albicans, which are highly associated with nosocomial infection. From the given results it is concluded that Cynodon dactylon could be exploited in pharmacology due to its antioxidant and anti-microbial properties.
Źródło:
Polish Journal of Chemical Technology; 2023, 25, 3; 110--119
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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