Autor: Sabri, K. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Multiple criteria and multiple periods performance analysis: the comparison of telecommunications sectors in the Maghreb countries
Autorzy:: Colson, G.
Sabri, K.
Mbangala, M.
Tematy:: case study
multiple criteria decision aid
Promethee
Malmquist DEA TFP index
African telecommunications reforms
dynamic performance analysis; Pokaż więcej
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/308878.pdf Link otwiera się w nowym oknie
Opis:: In four Maghreb countries (Algeria, Morocco, Mauritania and Tunisia), a considerable improvement of the situation of the telecommunication operators has been noticed during the nineties. The evolution in these countries was very different depending on their economic policies, their effort of reorganization of their telecommunication sector and their technological change. Theses differences will be exhibited and analysed by comparing the operators' performances over a decade (1992-2001). A first approach is based on the Malmquist DEA TFP index for measuring the total factors productivity change, decomposed into technical efficiency change and technological changes. Second, using the Promethee II method and the software ARGOS, a multiple criteria analysis is performed, taking into account a larger scope of analysis. A main issue is that the general performance ranking of sets of operators by country is almost the same according to the two methods, although the variables of inputs and output used for the index of Malmquist are different and narrower in the considered scope than the chosen families of criteria used in method Promethee and software ARGOS. Both methods of analysis provide however complementary useful detailed information, especially in discriminating the technological and management progresses for Malmquist and the two dimensions of performance for Promethee: that are the service to the community and the enterprises performances, often in conflict.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 2.

Tytuł:: Very-high-energy γ-ray emission from young massive star clusters in the Large Magellanic Cloud
Autorzy:: Schutte, H. M.
Rowell, G.
Montanari, A.
Marx, R.
Kundu, A.
Glicenstein, J. F.
Żywucka, N.
Jamrozy, Marek
Pühlhofer, G.
Martins, V. Barbosa
Benkhali, F. Ait
Ostrowski, Michał
Brown, A.
Böttcher, M.
Le Stum, S.
Leuschner, F.
Chibueze, O.
Ren, H.
Sushch, I.
Aschersleben, J.
White, R.
de Bony de Lavergne, M.
Mackey, J.
Kluźniak, W.
Renaud, M.
Mitchell, A.
Reimer, A.
Reville, B.
Vecchi, M.
de Naurois, M.
Lenain, J.-P.
Cristofari, P.
Ravikularaman, S.
Chandra, S.
Reimer, O.
Funk, S.
Horns, D.
Filipovic, M.
Sahakian, V.
Lang, R. G.
Egberts, K.
Casanova, S.
Moghadam, M. O.
Brose, R.
Hofmann, W.
Lemoine-Goumard, M.
Feijen, K.
Tsirou, M.
Schüssler, F.
Batzofin, R.
Ruiz-Velasco, E.
Mehta, A.
Borowska, J.
Wagner, S. J.
Bernlöhr, K.
Kosack, K.
Rudak, B.
Santangelo, A.
Spencer, S.
Zdziarski, A. A.
Jankowsky, F.
Bruno, B.
Cotter, G.
Khatoon, R.
Celic, J.
Jung-Richardt, I.
Katarzyński, K.
Brun, F.
Einecke, S.
Dmytriiev, A.
Devin, J.
Panny, S.
Chibueze, J.
Steppa, C.
Hinton, J. A.
Rieger, F.
Ashkar, H.
Heß, B.
Cerruti, M.
Lemière, A.
Sasaki, M.
Chand, T.
Stawarz, Łukasz
Niemiec, J.
Bolmont, J.
de Ona Wilhelmi, E.
Backes, M.
Berge, D.
Venter, C.
Pensec, U.
Aharonian, F.
Terrier, R.
Tsuji, N.
Khélifi, B.
Moderski, R.
Taylor, A. M.
Chen, A.
Becherini, Y.
Regeard, M.
Haerer, L.
Huang, Zhiqiu
Zacharias, M.
Marandon, V.
Peron, G.
Burger-Scheidlin, C.
Holch, T. L.
Sabri, K.
Gabici, S.
Vink, J.
Kostunin, D.
Djuvsland, J.
Grolleron, G.
Wierzcholska, A.
Djannati-Ataï, A.
Moulin, E.
Steinmassl, S.
van Eldik, C.
Martí-Devesa, G.
Ohm, S.
Olivera-Nieto, L.
Kasai, E.
Streil, K.
Zech, A.
Gallant, Y. A.
Komin, Nu.
Salzmann, H.
Schäfer, J.
Fontaine, G.
Mohrmann, L.
Quirrenbach, A.
Glombitza, J.
Sol, H.
Opis:: The Tarantula Nebula in the Large Magellanic Cloud is known for its high star formation activity. At its center lies the young massive star cluster R136, providing a significant amount of the energy that makes the nebula shine so brightly at many wavelengths. Recently, young massive star clusters have been suggested to also efficiently produce very high-energy cosmic rays, potentially beyond PeV energies. Here, we report the detection of very-high-energy γ-ray emission from the direction of R136 with the High Energy Stereoscopic System, achieved through a multicomponent, likelihood-based modeling of the data. This supports the hypothesis that R136 is indeed a very powerful cosmic-ray accelerator. Moreover, from the same analysis, we provide an updated measurement of the γ-ray emission from 30 Dor C, the only superbubble detected at TeV energies presently. The γ-ray luminosity above 0.5 TeV of both sources is (2–3) × 10$^{35}$ erg s$^{−1}$. This exceeds by more than a factor of 2 the luminosity of HESS J1646−458, which is associated with the most massive young star cluster in the Milky Way, Westerlund 1. Furthermore, the γ-ray emission from each source is extended with a significance of >3σ and a Gaussian width of about 30 pc. For 30 Dor C, a connection between the γ-ray emission and the nonthermal X-ray emission appears likely. Different interpretations of the γ-ray signal from R136 are discussed.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

Artykuł

na półce

Skocz do pozycji: 3.

Tytuł:: H.E.S.S. programme searching for VHE gamma rays associated with FRBs
Autorzy:: Schüssler, F.
Batzofin, R.
Mehta, A.
Holler, M.
Niemiec, J.
Fontaine, G.
Santangelo, A.
Lenain, J.-P.
Aharonian, F.
Kostunin, D.
Ren, H.
de Ona Wilhelmi, E.
Regeard, M.
Khatoon, R.
Kasai, E.
Wierzcholska, Alicja
Takahashi, T.
Sasaki, M.
Spencer, S.
Steppa, C.
Schäfer, J.
Barbosa Martins, V.
Sharma, A.
Punch, M.
Brose, R.
Reimer, O.
Boisson, C.
Casanova, S.
Huang, Zhiqiu
Wach, T.
Bradascio, F.
Katarzyński, K.
Venter, C.
Chibueze, O.
Kluźniak, W.
Bernlöhr, K.
Böttcher, M.
Brun, F.
Panny, S.
Cerruti, M.
Marandon, V.
van Eldik, C.
Borowska, J.
Sabri, K.
Stawarz, Łukasz
Salzmann, H.
Rudak, B.
Bolmont, J.
Kerszberg, D.
Schutte, H.M.
Parsons, R.D.
Escañuela Nieves, C.
Jaitly, A.
de Naurois, M.
Moulin, E.
Kosack, K.
Żywucka-Hejzner, Natalia
Chand, T.
Mitchell, A.
Archaryya, A.
Lang, R.G.
Gabici, S.
Funk, S.
Ravikularaman, S.
Chen, A.
Steinmassl, S.
Olivera-Nieto, L.
Tsirou, M.
Dmytriiev, A.
Heß, B.
Chandra, S.
Ernenwein, J.-P.
Ostrowski, Michał
Moghadam, M.O.
Djannati-Ataï, A.
Kundu, A.
Khélifi, B.
Le Stum, S.
Jamrozy, Marek
Mackey, J.
Moderski, R.
Einecke, S.
O'Brien, P.
Becherini, Y.
Quirrenbach, A.
Aschersleben, J.
Tanaka, T.
Rowell, G.
Damascene Mbarubucyeye, J.
Meyer, M.
Jung-Richardt, I.
Chibueze, J.
Bruno, B.
Lemoine-Goumard, M.
Pensec, U.
Backes, M.
Djuvsland, J.
Vecchi, M.
Filipovic, M.
Horns, D.
Malyshev, D.
Zdziarski, A.A.
Grolleron, G.
Glicenstein, J.F.
Marx, R.
Rieger, F.
Berge, D.
Lemière, A.
de Assis Scarpin, J.
Pühlhofer, G.
Celic, J.
Brown, A.
Ashkar, H.
de Bony de Lavergne, M.
Hofmann, W.
Luashvili, A.
Egberts, K.
Wagner, S.J.
Shapopi, J.N.S.
Panter, M.
Jankowsky, F.
Burger-Scheidlin, C.
Glombitza, J.
Holch, T.L.
Pita, S.
Sahakian, V.
Reville, B.
Zech, A.
Steenkamp, R.
Komin, Nu.
Opis:: Fast Radio Bursts (FRBs) are highly energetic, extremely short-lived bursts of radio flashes. Despite extensive research, the exact cause of these outbursts remains speculative. The high luminosity, short duration, and high dispersion measure of these events suggest they result from extreme, high-energy extragalactic sources, such as highly magnetized and rapidly spinning neutron stars known as magnetars. The number of detected FRBs, including repeating ones, has grown rapidly in recent years. Except for FRB 20200428D, and FRB-like radio burst that is associated to Galactic magnetar SGR 1935+2154, no multi-wavelength counterpart to any FRB has been detected yet. The High Energy Stereoscopic System (H.E.S.S.) telescope has developed a program to follow up FRBs searching for their gamma-ray counterparts, helping to uncover the nature of FRBs and FRB sources. This paper provides an overview of the searches for FRB sources conducted by H.E.S.S., including follow-up observations and simultaneous multi-wavelength campaigns with radio and X-ray observatories. Among the FRB sources observed by H.E.S.S., nine are localized with redshifts ranging between 0.11 and 0.492 from 2015 to 2022. No significant very high energy (VHE) emission was detected during these observations. We report constraints on the VHE luminosity ranging from 10$^{44}$ erg s$^{-1}$ and 10$^{48}$ erg s$^{-1}$, placing limits on the FRB's region persistent VHE emission and potential FRB afterglow emission across timescales from hours to years.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

Artykuł

na półce

Skocz do pozycji: 4.

Tytuł:: Detection of very high-energy gamma-ray emission from Eta Carinae during its 2020 periastron passage
Autorzy:: Schüssler, F.
Holch, T. L.
Batzofin, R.
Mehta, A.
Holler, M.
Niemiec, J.
Fontaine, G.
Ruiz-Velasco, E.
Santangelo, A.
Lenain, J.-P.
Aharonian, F.
Kostunin, D.
Lang, R. G.
de Ona Wilhelmi, E.
Ren, H.
Streil, K.
Regeard, M.
Ohm, S.
Marcowith, A.
Khatoon, R.
Wierzcholska, Alicja
Sasaki, M.
Spencer, S.
Steppa, C.
Schäfer, J.
Barbosa Martins, V.
Ait Benkhali, F.
Brose, R.
Reimer, O.
Boisson, C.
Casanova, S.
Moghadam, M. O.
Werner, F.
Wach, T.
Bradascio, F.
Katarzyński, K.
Collins, T.
Mohrmann, L.
Venter, C.
Chibueze, O.
Kluźniak, W.
Bernlöhr, K.
Huang, Z.
Böttcher, M.
Brun, F.
Panny, S.
Tluczykont, M.
Cerruti, M.
Marandon, V.
van Eldik, C.
Schutte, H. M.
Sabri, K.
Stawarz, Łukasz
Hinton, J. A.
Salzmann, H.
Martí-Devesa, G.
Rudak, B.
Bolmont, J.
Reimer, A.
Escañuela Nieves, C.
de Naurois, M.
Moulin, E.
Kosack, K.
Żywucka-Hejzner, Natalia
Wagner, S. J.
Feijen, K.
Chand, T.
Mitchell, A.
Gabici, S.
Funk, S.
Ravikularaman, S.
Grondin, M.-H.
Chen, A.
Steinmassl, S.
Olivera-Nieto, L.
Tsirou, M.
Dmytriiev, A.
Heß, B.
Chandra, S.
Ernenwein, J.-P.
Ostrowski, Michał
Jardin-Blicq, A.
Djannati-Ataï, A.
Khélifi, B.
Le Stum, S.
Jamrozy, Marek
Shapopi, J. N. S.
Cotter, G.
Mackey, J.
Moderski, R.
Remy, Q.
Einecke, S.
Becherini, Y.
Quirrenbach, A.
Aschersleben, J.
Tanaka, T.
White, R.
Rowell, G.
Damascene Mbarubucyeye, J.
Jung-Richardt, I.
Chibueze, J.
Bruno, B.
Lemoine-Goumard, M.
Haerer, L.
Pensec, U.
Djuvsland, J.
Vecchi, M.
Filipovic, M.
Horns, D.
Malyshev, D.
Grolleron, G.
Marx, R.
Glicenstein, J. F.
Rieger, F.
Berge, D.
Lemière, A.
Terrier, R.
de Assis Scarpin, J.
Parsons, R. D.
Pühlhofer, G.
Celic, J.
Brown, A.
Ashkar, H.
de Bony de Lavergne, M.
Hofmann, W.
Luashvili, A.
Tsuji, N.
Egberts, K.
Panter, M.
Jankowsky, F.
Burger-Scheidlin, C.
Devin, J.
Sahakian, V.
Zdziarski, A. A.
Reville, B.
Zech, A.
Steenkamp, R.
Zacharias, M.
Komin, Nu.
Opis:: The colliding-wind binary system η Carinae has been identified as a source of high-energy (HE, below ∼100 GeV) and very high-energy (VHE, above ∼100 GeV) gamma rays in the last decade, making it unique among these systems. With its eccentric 5.5-year-long orbit, the periastron passage, during which the stars are separated by only 1–2 au, is an intriguing time interval to probe particle acceleration processes within the system. In this work, we report on an extensive VHE observation campaign that for the first time covers the full periastron passage carried out with the High Energy Stereoscopic System (H.E.S.S.) in its 5-telescope configuration with upgraded cameras. The VHE gamma-ray emission from η Carinae was detected during the periastron passage with a steep spectrum with the spectral index Γ = 3.3 ± 0.2stat ± 0.1syst. Together with previous and follow-up observations, we derive a long-term light curve sampling one full orbit, showing hints of an increase in the VHE flux towards periastron, but no hint of variability during the passage itself. An analysis of contemporaneous Fermi-LAT data shows that the VHE spectrum represents a smooth continuation of the HE spectrum. From modelling the combined spectrum, we conclude that the gamma-ray emission region is located at distances of ∼10–20 au from the centre of mass of the system and that protons are accelerated up to energies of at least several tera-electronvolts inside the system in this phase.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

Artykuł

na półce

Skocz do pozycji: 5.

Tytuł:: Microplastics Evaluation in Tap Water in Left Side Districts of Mosul City, Iraq
Autorzy:: Sultan, Mhmood Hameed
Al-Ahmady, Kossay K.
Mhemid, Rasha Khalid Sabri
Tematy:: microplastics
drinking water
treatment plant
Fourier transform infrared spectroscopy
stereomicroscope
tap water; Pokaż więcej
Wydawca:: Polskie Towarzystwo Inżynierii Ekologicznej
Powiązania:: https://bibliotekanauki.pl/articles/59114108.pdf Link otwiera się w nowym oknie
Opis:: Microplastics (MPs) are considered as recently identified pollutants in the tap water of Mosul city. Limited studies on the quantity and features of microplastics have been reported. Consequently, this study examined the number and characteristics of MPs in tap water from 16 districts in left side of Mosul city, including 8 districts that receive drinking water from the Alaysar aljadid drinking water treatment plant (AJ-DWTP) and 8 districts that receive drinking water from the Alaysar alqadim drinking water treatment plant (AQ-DWTP). Infrared Fourier-transform spectroscopy (FTIR) and stereo microscopy were used to determine the microplastic abundance, polymer type, and morphology characteristics (colour and shape). The results showed that the abundances of MPs calcualted in tap water in AJ-WDN and AG-WDN were 35 to 70 items/L and 25 to 71 items/L, respectively. The predominant shape of microplastics was fiber and fragment, accounting for 93% of the identified quantities. The most common polymer types were polyvinyl chloride (PVC) (51%) followed by polyamide (PA) (16%). Statistical analysis was conducted on the results using Exel 2019. The microplastic’s risk has been estimated based on the potential risk index of polymers. In both the water distribution networks of AQ and AJ, MPs’ potential risk was significantly similar.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 6.

Tytuł:: Study the Effectiveness of Household Water Filtration Systems in Eliminating Plastic Particles in Mosul City, Iraq
Autorzy:: Altaee, Raghad N.
Al-Ahmady, Kossay K.
Mhemid, Rasha Khalid Sabri
Tematy:: microplastics
removal efficiency
household water filter system
HWFS
Fourier transform infrared spectroscopy
stereomicroscope
scanning electron microscopy; Pokaż więcej
Wydawca:: Polskie Towarzystwo Inżynierii Ekologicznej
Powiązania:: https://bibliotekanauki.pl/articles/59113781.pdf Link otwiera się w nowym oknie
Opis:: Plastic particles are considered a concerning issue on a global scale. This research aimed to examine the existence and features of microplastics (MPs) as well as evaluate the removal efficiency (RE%) of household water filter systems (HWFS). The research was conducted in 12 areas distributed across Mosul City. Various techniques, including Fourier transform spectroscopy (FTIR), stereomicroscopy, and scanning electron microscopy (SEM), were employed to accurately detect the presence of microplastics, analyze morphological properties, such as color, shape, and size, and determine the polymer types. The research findings showed that the efficiency of HWFS ranged from 93% to 30%, affected by several factors, including filter age and the number of its stages. Fibers and fragments were the most commonly encountered shapes of MPs accounting for about 94% of the examined instances. Around 52% of the total was characterized by a transparent color. An estimated 35% of MPs sizes were smaller than 10 µm. Out of all considered polymer types, polyvinyl chloride (PVC) represented the highest percentage, around 58%. Moreover, PVC was found to have a higher risk index compared to other types of polymers.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 7.

Tytuł:: An Investigation of Microplastic Occurrence and Heavy Metals Concentrations in Street Dust on the Left Side of Mosul City, Iraq
Autorzy:: Almola, Marah Ayad
Al-Ahmady, Kossay K.
Mhemid, Rasha Khalid Sabri
Tematy:: microplastic
heavy metals
FTIR
Fourier Transform Infrared Spectroscopy
street dust
ecological risk
enrichment factor
ecological risk index; Pokaż więcej
Wydawca:: Polskie Towarzystwo Inżynierii Ekologicznej
Powiązania:: https://bibliotekanauki.pl/articles/59113844.pdf Link otwiera się w nowym oknie
Opis:: The issue of street dust pollution is primarily related to levels of microplastic particles (MPs) and heavy metals, raising concerns about their potential risk to the environment. In this work, twenty street dust samples with three replicates were collected from different areas (residential, commercial, and industrial) on the left side of Mosul city/Iraq, to investigate the presence of MPs and study their characteristics. Additionally, to assess the potential ecological risk impact of twelve heavy metals. Among the 60 dust samples taken from the streets, an average of MPs ranging between 244 and 2760 per 15 grams of dust was detected. Most of these plastic particles were transparent fragments with sizes varying from less than 10 to 200 µm as observed through a stereomicroscope and a scanning electron microscope (SEM). Furthermore, results from FTIR analysis indicated that polyvinyl chloride (PVC) was the dominant polymer type found in MPs, accounting for around 63%. The levels of metal in road dust were assessed using X-ray fluorescence (XRF) showing that quantification of Cr, Ni, Cu, Zn, As, Sb, Hg, and Pb surpassed the background values of world soils among the twelve elements studied. Variation coefficients (VCs) coupled with enrichment and contamination factors revealed that Cr, Cu, Zn, As, Se, Cd, Sb, Hg, and Pb are associated with both sources (anthropogenic and natural). On the other hand, Mn, Fe, and Ni originate from natural sources. Calculated potential ecological risk (Er) indicated high ecological risk by Hg. Approximately half of the samples exhibited moderate ecological risk indices (RI).
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 8.

Tytuł:: Effect of the Longitudinal Magnetic Field on the Electrical Breakdown in Argon and Nitrogen Plasma Discharges
Autorzy:: Khalaf, Mohammed K.
Mohammed, Sabri J.
Majeed, Muataz A.
Jasim, Hanaa E.
Tematy:: Paschen curves
Minimum breakdown voltage
Townsend coefficient
Ionization efficiency
Permanent Magnet; Pokaż więcej
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Powiązania:: https://bibliotekanauki.pl/articles/1192598.pdf Link otwiera się w nowym oknie
Opis:: The electrical breakdown has been studied for low-pressure argon and nitrogen discharges under the influence of a longitudinal magnetic field. Plane-parallel stainless steel electrodes (7.25 cm diameter) separated at the distance d (2.0 cm) were sustained with a dc voltage (0 - 700 V). Permanent magnets was used to produce an uniform magnetic field (B = 855G) parallel to the discharge axis. Paschen curves are obtained and the first Paschen curves, these curves are plotted for fixed values of B = 0 and B = 855 Gauss. The effect of longitudinal magnetic field becomes more significanor to obtain values of η, but it is less for the values of γ, separations (2cm) and different working pressure contributes Townsend discharge regime at a new range of plane-parallel electrode. The results show that by increasing of magnetic field Townsend coefficient and the ionization efficiency of the system significantly enhances.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 9.

Tytuł:: Assessment of Indoor Microplastic Particles Pollution in Selected Sites of Mosul City
Autorzy:: Al-Hussayni, Rihab Salih
Al-Ahmady, Kossay K.
Mhemid, Rasha Khalid Sabri
Tematy:: microplastic
dust deposition
shape
colour
FTIR
indoor air pollution
indoor dust; Pokaż więcej
Wydawca:: Polskie Towarzystwo Inżynierii Ekologicznej
Powiązania:: https://bibliotekanauki.pl/articles/59114133.pdf Link otwiera się w nowym oknie
Opis:: Among the most significant sources of microplastics (MPs) for humans is indoor dust. However, very few researchers have studied the properties and abundance of MPs that existed in dust from different indoor environments. The current study investigated microplastic fallout in 90 locations (5 kindergartens, 6 mosques, 5 schools, 10 shops, 5 cafeterias, 6 hospitals, 25 dormitories, 7 barber salons, 6 offices, 5 scientific laboratories, 5 pharmacies, and 5 medical clinics) during six months. Among the ninety sampling sites, the most significant average of MPs was actually found in the kindergartens (4.743×103 ± 427 MP/m2 /d), in contrast, the lowest abundance was in the medical clinics (3.02×102 ± 62 MP/m2 /d). The majority of indoor dust samples contained MPs in the form of fibers. The dominant colour of dust samples was transparent, followed by black, red, blue, green, and yellow. A total of six types of polymers were identified, including polystyrene (PS, 39%), polyethylene terephthalate (PET, 20%), polypropylene (PP, 17%), polyethylene (PE, 13), polyamide (PA, 7%) and polyvinyl chloride (PVC, 3%). PS, PET, and PP represent most of the MPs polymer types discovered in indoor dust samples from various locations. These polymers are frequently used in fabrics, furniture, carpets, packaging, and synthetic fibers. Statistical analysis was performed on the results using Excel 2019. The results showed that there were statistically significant differences in each site with the other sites, except between (schools and mosques), (pharmacies, and medical clinics). The similarity between these sites in terms of people’s activity or in terms of furniture, the lack of carpets and curtains could explain the insignificant difference.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 10.

Tytuł:: Axisymmetric free vibration of layered cylindrical shell filled with fluid
Autorzy:: Izyan, M. D. Nurul
Sabri, Nur Ain Ayunni
Hafizah, A. K. Nor
Sankar, D. S.
Viswanathan, K. K.
Tematy:: drgania swobodne
powłoka cylindryczna
efekt Love'a
axisymmetric
free vibration
cylindrical shell
Love’s first approximation theory
inviscid fluid
spline approximation
eigenvalues; Pokaż więcej
Wydawca:: Uniwersytet Zielonogórski. Oficyna Wydawnicza
Powiązania:: https://bibliotekanauki.pl/articles/2106463.pdf Link otwiera się w nowym oknie
Opis:: The aim of the study is to analyse the axisymmetric free vibration of layered cylindrical shells filled with a quiescent fluid. The fluid is assumed to be incompressible and inviscid. The equations of axisymmetric vibrations of layered cylindrical shell filled with fluid, on the longitudinal and transverse displacement components are obtained using Love’s first approximation theory. The solutions of displacement functions are assumed in a separable form to obtain a system of coupled differential equations in terms of displacement functions. The displacement functions are approximated by Bickley-type splines. A generalized eigenvalue problem is obtained and solved numerically for a frequency parameter and an associated eigenvector of spline coefficients. Two layered shells with three different types of materials under clamped-clamped boundary conditions are considered. Parametric studies are made on the variation of the frequency parameter with respect to length-to-radius ratio and length-to-thickness ratio.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Informacja

Wyszukujesz frazę "Sabri, K." wg kryterium: Autor