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Wyszukujesz frazę "Safa, M." wg kryterium: Autor


Wyświetlanie 1-6 z 6
Tytuł:
A simulated annealing based optimization algorithm for automatic variogram model fitting
Symulacja algorytmu optymalizacyjnego procesu odprężania dla automatycznego dopasowania modelu wariogramu
Autorzy:
Soltani-Mohammadi, S.
Safa, M.
Powiązania:
https://bibliotekanauki.pl/articles/219828.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
automatyczne dopasowanie wariogramu
geostatystyka
optymalizacja
symulacje procesu odprężania
automatic variogram fitting
geostatistics
optimization
simulated annealing
Opis:
Fitting a theoretical model to an experimental variogram is an important issue in geostatistical studies because if the variogram model parameters are tainted with uncertainty, the latter will spread in the results of estimations and simulations. Although the most popular fitting method is fitting by eye, in some cases use is made of the automatic fitting method on the basis of putting together the geostatistical principles and optimization techniques to: 1) provide a basic model to improve fitting by eye, 2) fit a model to a large number of experimental variograms in a short time, and 3) incorporate the variogram related uncertainty in the model fitting. Effort has been made in this paper to improve the quality of the fitted model by improving the popular objective function (weighted least squares) in the automatic fitting. Also, since the variogram model function (£) and number of structures (m) too affect the model quality, a program has been provided in the MATLAB software that can present optimum nested variogram models using the simulated annealing method. Finally, to select the most desirable model from among the single/multi-structured fitted models, use has been made of the cross-validation method, and the best model has been introduced to the user as the output. In order to check the capability of the proposed objective function and the procedure, 3 case studies have been presented.
Dopasowanie modelu teoretycznego do eksperymentalnego wariogramu jest kluczowym zagadnieniem w badaniach geostatystycznych ponieważ jeśli parametry modelu wariogramu obarczone są niepewnością, to otrzymamy znaczny rozrzut wyników obliczeń i symulacji. Pomimo, że najpopularniejszą metoda dopasowania jest dopasowanie ‘na oko’, w niektórych przypadkach wykorzystuje się automatyczne metody dopasowania modelu oparte na zasadach geostatystyki i optymalizacji w celu: 1) dostarczenia podstawowego modelu do dopasowania ‘na oko’; 2) dopasowania modelu do większej ilości eksperymentalnych wariogramów w krótkim okresie czasu; 3) uwzględnienia niepewności związanej z wariogramem w dopasowaniu modelu. W pracy podjęto próbę poprawy jakości dopasowania modelu poprzez wprowadzenie zmodyfikowanej popularnej funkcji celu (ważone najmniejsze kwadraty) do au- tomatycznego dopasowania. Ponadto, ponieważ funkcja modelu wariogramu (L) i ilość struktur (m) ma także wpływ na jakość modelu, opracowano program w środowisku MATLAB który podaje optymalne modele wariogramu w oparciu o metodę symulacji odprężania. W części końcowej wybrano najkorzystniejszy model spośród modeli dopasowania z wykorzystaniem metody walidacji krzyżowej i najlepszy model przedstawiany jest użytkownikowi. W celu zbadania możliwości stosowania proponowanej funkcji celu i przedstawionej procedury, zaprezentowano trzy studia przypadku.
Źródło:
Archives of Mining Sciences; 2016, 61, 3; 635-649
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wind tunnel flux comparisons using a phase Doppler interferometer
Autorzy:
Roten, R.L.
Post, S.L.
Werner, A.
Safa, M.
Hewitt, A.J.
Powiązania:
https://bibliotekanauki.pl/articles/65512.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wind tunnel
flux measurement
Doppler interferometer
phase Doppler system
droplet
Opis:
It is essential to know the movement of droplets in time and space (i.e. flux) when measuring and/or predicting spray drift in agricultural application. A study was performed to assess the flux measurements of a phase Doppler system against a standard monofilament system in a wind tunnel. The primary objectives of the study were to compare flux from a new phase Doppler system against 1.7 mm cotton and 2.0 mm nylon strings at varying wind speeds (1.4, 4.2, 8.3, 12.5, and 16.7 m ⋅ s–1) and spray exposures times (5, 10, 15, 30, and 60 s) with an overarching hypothesis that the active, phase Doppler is able to accurately measure the flux regardless of exposure and spray mass whereas the static string samplers are limited to a maximum retention. The phase Doppler did measure linearly as expected, however strings did not reach a point in which they loss mass; conversely, they appeared to overload with saturation. These findings are believed to be among many variables which influence the variability of previous mass balance studies.
Źródło:
Journal of Plant Protection Research; 2017, 57, 3
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Increase of Hydrogen Storage Capacity of CNTs by Using Transition Metal, Metal Oxide-CNT Nanocomposites
Autorzy:
Larijani, M.
Safa, S.
Powiązania:
https://bibliotekanauki.pl/articles/1205209.pdf
Data publikacji:
2014-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.82.Rx
68.37.Lp
81.07.De
88.30.R-
Opis:
In this paper, we examined the synergetic effect of transition metals or their oxides as decorative agent with carbon nanotubes on the hydrogen storage capacity. The $TiO_2$, Pd, and PdO shell nanoparticles were used as decorative agent on the surface of carbon nanotubes. The samples were investigated by X-ray diffraction, Raman spectroscopy and transmission electron microscopy. The thermal stability was investigated by thermogravimetric analysis testing. The hydrogen storage capacity was measured by a custom-made Sieverts apparatus. The Pd and $TiO_2$ doped carbon nanotube shows the most marked hydrogen storage capacity, 7 times higher than pristin carbon nanotubes after 30 min storage. The results show that the hydrogen storage capacity of the PdO shell- carbon nanotube composite is very low in comparison with those of two others and does not represent a significant difference with that of carbon nanotubes.
Źródło:
Acta Physica Polonica A; 2014, 126, 3; 732-735
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ion Beam Analysis of Hydrogen-Treated Ti/TiN Protective Nanomultilayers
Autorzy:
Kakuee, O.
Fathollahi, V.
Lamehi-Rachti, M.
Oliaiy, P.
Seyedi, H.
Safa, S.
Mojtahedzadeh Larijani, M.
Moazzami, H.
Powiązania:
https://bibliotekanauki.pl/articles/1419781.pdf
Data publikacji:
2012-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.43.-h
68.49.-h
81.15.Jj
25.45.-z
Opis:
Ti/TiN multilayer films with a few multilayer periods and a total sub-μm thickness were deposited on AISI 304 stainless steel substrates by ion coating deposition technique. To investigate the effect of hydrogen treatment on the corrosion behavior of the multilayers, some of the samples were hydrogen treated after deposition of the first and/or the second Ti interlayer. $\text{}^{14}N(d,\alpha_1) \text{}^{12}C$ nuclear reaction and the Rutherford backscattering spectrometry were used to obtain the atomic composition profiles and thickness of Ti/TiN layers. Nuclear reaction analysis confirmed the presence of two separable TiN layers of comparable thickness on the surface and in depth of the two-period multilayers. These techniques were used to determine the thickness of individual Ti and TiN layers and revealed that the stoichiometry of TiN layers was approximately Ti:N=1:1. Hydrogen depth profile in the prepared samples was obtained by elastic recoil detection analysis. It was found that a remarkable volume of hydrogen was uptaken by the Ti layer in the hydrogen treated samples. The TiN (200) diffraction peak in the X-ray diffraction pattern was observed with different intensities depending on the sample preparation parameters. The corrosion behavior of the multilayers was studied by means of potentiodynamic polarization in 0.5 M NaCl solutions. It was found that the hydrogen treatment of Ti interlayer could potentially improve the corrosion properties of the Ti/TiN layers.
Źródło:
Acta Physica Polonica A; 2012, 122, 1; 132-137
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Baseline study in environmental risk assessment : site-specific model development and application
Autorzy:
Alam, Asifa
Mahmood, Adeel
Chaudhry, M. Nawaz
Ahmad, Sajid Rashid
Safa, Noor Ul
Alghamdi, Huda Ahmed
Alhamdi, Heba Waheeb
Ullah, Rizwan
Powiązania:
https://bibliotekanauki.pl/articles/2203136.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
baseline study
risk assessment models
risk management
mathematical approaches
landfills
dumping sites
environmental risk estimation
Opis:
Environmental risk assessment is one of the key tools in environmental engineering. This risk assessment can be qualitative or quantitative and it is based on preliminary studies i.e., baseline study for waste disposal sites. Even though the literature exists on baseline study in general, still there is a lack of guidance regarding development of a site-specific baseline study model for a waste disposal site. This study has two-fold aim, firstly, how to develop site-specific baseline study model for a selected dumping site, and secondly, how this site-specific baseline study can support the environmental engineering via mathematical risk estimation. Mahmood Booti Open Dumping Site (MBODS) is selected to demonstrate the development and application of site-specific baseline study model. This is followed by building a framework that shows how the output of the baseline study can lead to environmental engineering via mathematical risk estimation. The paper provides a mechanism of how to construct a bespoke baseline-study model that is readily useable, avoiding procurement of expensive computer software and yet smoothly connecting with the follow-on stages of the risk assessment. The work presented in this paper can be reproduced repeatedly to create site-specific baseline study models for risk assessment of other waste disposal sites in a cost-effective, consistent and cohesive manner.
Źródło:
Archives of Environmental Protection; 2022, 48, 3; 80--88
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis, computational, anticancerous and antiproliferative effects of some copper, manganese and zinc complexes with ligands derived from symmetrical 2,2’-diamino-4,4’-dimethyl-1,1’-biphenyl-salicylaldehyde
Autorzy:
Ababneh, Taher S.
El-Khateeb, Mohammad
Tanash, Aissar K.
AL-Shboul, Tareq M.A.
Shammout, Mohammad Jamal A.
Jazzazi, Taghreed M.A.
Alomari, Mohammad
Daoud, Safa
Talib, Wamidh H.
Powiązania:
https://bibliotekanauki.pl/articles/1849324.pdf
Data publikacji:
2021
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
tetradentate schiff base
symmetrical metal complexes
DFT calculation
spectroscopy
anticancerous
antiproliferative
Opis:
Four new symmetrical Schiff bases derived from 2,2’-diamino-4,4’-dimethyl-1,1’-biphenyl-salicylaldehyde have been synthesized and characterized by elemental analysis and different spectroscopic techniques. The reaction of 2,2’-diamino-4,4’-dimethyl-1,1’-biphenyl with two equivalents of 5-tert-butyl-, 3,5-dinitro-, 3,5-dibromo- and 3-tert-butyl-salicylaldehyde yielded 2,2’-bis(5-tert-butyl-salicylideneamino)-4,4’-dimethyl-1,1’-biphenyl (A1) as well as the 3,5-dinitro- (A2), 3,5-dibromo- (A3) and 3-tert-butyl- (A4) substituted derivatives. The tetradentate ligands were then reacted with copper-, manganese- and zinc-acetate producing the tetra-coordinate metal complexes which were characterized by FTIR, UV-Visible spectroscopy, magnetic susceptibility and elemental analysis. Zinc complexes were characterized by 1H-NMR spectroscopy. Density functional theory (DFT) calculations at the B3LYP/6-31G(d) level of theory were carried out to fully optimize and examine the molecular geometries of complexes. Subsequently, IR vibrational and UV-Vis absorption spectra were computed and correlated with the observed values and the results are in good agreement with the experimental data. The anticancerous and antiproliferative activity of the A3 ligand and its metal complexes were determined.
Źródło:
Polish Journal of Chemical Technology; 2021, 23, 1; 7-15
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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