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Wyszukujesz frazę "Hosseini, S." wg kryterium: Autor


Tytuł:
Contrasting foliar and soil nutrients responses to drought induced crown dieback in a Quercus brantii forest
Autorzy:
Hosseini, A.
Hosseini, S.M.
Powiązania:
https://bibliotekanauki.pl/articles/2130168.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
crown condition
drought
nutrients
persian oak forests
tree decline
Opis:
Evidence has shown that drought-induced crown dieback has significant interaction with soil-plant water and nutrients relationships, but there isn’t sufficient knowledge of the water and nutrients connections in declining Persian oak (Quercus brantii) trees. To investigate the relationships between crown dieback and leaf nutrients concentrations, leaf water content, soil nutrients concentrations and soil moisture, one of the dieback affected stands was selected. This stand was located in Shalam forested area in northern Ilam province, west of Iran. Persian oak trees were evaluated using a crown dieback classification and divided into four classes with four replicates based on the severity of crown dieback. Sampling from leaves of trees and soil was implemented randomly in four sides of tree crown in August. Trees with moderate to severe declining showed reduced leaf water content (WC) and reduced relative leaf water content (RWC). Leaf N and P concentration of declining trees was significantly (p-value <0.05) more than that of healthy trees. The leaf K concentration of declining trees was significantly (p-value <0.10) more than that of the healthy. The leaf N:P amounts of oak trees was statistically different among crown dieback classes. But no significant differences was observed between the healthy and declining trees in terms of soil N, P, K, Ca and Mg concentrations and soil moisture. It was concluded that drought has effects on the nutrients status in the leaves of Persian oak trees and their changing in the declining trees is for resistance to drought condition, improving water use efficiency and possibly performance of vital activities.
Źródło:
Dendrobiology; 2022, 87; 101-112
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dual-Frequency Plasma Enhanced Chemical Vapor Deposition of Diamond-Like Carbon Thin Films
Autorzy:
Jamshidi, R.
Hosseini, S.
Ahmadizadeh, Y.
Powiązania:
https://bibliotekanauki.pl/articles/1419912.pdf
Data publikacji:
2012-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Gh
Opis:
Dual-frequency plasma enhanced chemical vapor deposition was used to grow diamond-like carbon thin films from $CH_4,$ $H_2$ gas mixture. The effects of radio frequency, microwave power, and gas ratio were investigated. Various species have been identified in the $CH_4-H_2$ plasma using optical emission spectroscopy and their effects on film properties have been studied. Increasing the RF power to 400 W, the variation trend of refractive index and CH, $C_2$ intensity ratios change beyond the 300 W, but the growth rate shows the continuous increasing character from 6 to 11.6 nm/min. Increasing the hydrogen content in the system, the intensity ratio of CH, $C_2$, $CH^{+}$ and growth rate show decreasing tendency and the refractive index rises from 1.98 to 2.63. Adding MW produced plasma to the system grows the refractive index to 2.88 and growth rate to 10.8 nm/min. The water contact angle rises from 58.95° to 73.74° as the RF power increases to 300 W but begins to reduce until 400 W. In addition, the contact angle shows a growing tendency by increasing the hydrogen flow to the chamber. In addition, the structures of the films were investigated by the Raman spectroscopy.
Źródło:
Acta Physica Polonica A; 2012, 122, 1; 230-235
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vulnerability assessment of Southern coastal areas of Iran to sea level rise: evaluation of climate change impact
Autorzy:
Goharnejad, H.
Shamsai, A.
Hosseini, S.A.
Powiązania:
https://bibliotekanauki.pl/articles/48331.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
climate change
sea level rise
coastal area
Iran
general circulation model
sea-level change
artificial intelligence
artificial neural network
hydrological model
Źródło:
Oceanologia; 2013, 55, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dispersive Micro Raman Backscattering Spectroscopy Investigation of Arc Discharge Synthesized CNTs Doped by Boron and Nitrogen
Autorzy:
Babanejad, S.
Malekfar, R.
Seyyed Hosseini, S.
Powiązania:
https://bibliotekanauki.pl/articles/1807785.pdf
Data publikacji:
2009-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.Fg
63.22.Gh
78.67.Ch
81.07.De
Opis:
Raman scattering studies reveal the remarkable structure and the unusual electronic and phonon properties of carbon nanotubes. In this study, we directly produced boron, B, and nitrogen doped carbon nanotubes by using DC-arc discharge method which normally can be employed for producing carbon nanotubes. We performed experiments without using catalysts and in the presence of Ar gas for producing boron doped carbon nanotubes. At the second and third stages and in the presence of $Al_{2}O_{3}$ and MgO nanopowders as catalysts and nitrogen gas were used for producing nitrogen doped carbon nanotubes. In general, our investigation revealed that some major changes caused by B and N dopants can be observed in the related recorded Raman spectra.
Źródło:
Acta Physica Polonica A; 2009, 116, 2; 217-220
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis, Characterization, and Application of Stabilized-Ni/Fe Bimetallic Nanoparticles for the Selective Elimination of Chlorate Impurity in Military Grade Ammonium Perchlorate
Autorzy:
Zarei, A. R.
Moloudi, A.
Hosseini, S. G.
Powiązania:
https://bibliotekanauki.pl/articles/951495.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
ammonium perchlorate
chlorate
selective elimination
stabilized-Ni/Fe bimetallic nanoparticles
solid propellants
Opis:
Ammonium perchlorate (AP) is used as the most common oxidizer in composite solid propellants. Control of chlorate impurity in military grade ammonium perchlorate is important, since it has an undesirable effect on the thermal decomposition of ammonium perchlorate. In this work stabilized Ni/Fe bimetallic nanoparticles (S-Ni/Fe NPs) were synthesized using the borohydride reduction method (BRM) in the presence of starch as a stabilizing agent, and they were characterized by field emission scanning electron microscopy (SEM), and their X-ray diffraction pattern (XRD). The results showed that the synthesized S-Ni/Fe bimetallic nanoparticles were spherical in shape and had nearly uniform distribution, with particle sizes of 20-50 nm. The prepared nanoparticles were then used for the selective elimination of chlorate impurity in ammonium perchlorate. The main factors controlling the elimination of chlorate, such as the initial pH of the solution, dosage of S-Fe/Ni NPs, initial chlorate and perchlorate concentrations, reaction temperature, and reaction time, were optimized by using an experimental design based on the Taguchi method. An L9 orthogonal array (L9-OA) was used to design experiments with four 4-level factors (34). Under the optimal conditions, i.e., pH 6.5, at 30 °C and a dosage of 50 mg S-Ni/Fe NPs, chlorate was eliminated with nearly 100% efficiency in 50 mL of a solution containing 2.0 μg·mL−1 and 100 μg·mL−1 of chlorate and perchlorate, respectively, without change in perchlorate concentration.
Źródło:
Central European Journal of Energetic Materials; 2017, 14, 1; 120-133
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model development of integrated CPOx reformer and SOFC stack system
Autorzy:
Pianko-Oprych, P.
Hosseini, S. M.
Jaworski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/779855.pdf
Data publikacji:
2016
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Catalytic Partial Oxidation (CPOx) reformer
Solid Oxide Fuel Cell (SOFC) stack
stead and dynamic mode
modelling
Opis:
The main purpose of this study was to develop a mathematical model, in a steady state and dynamic mode, of a Catalytic Partial Oxidation (CPOx ) reformer – Solid Oxide Fuel Cell (SOFC) stack integrated system in order to assess the system performance. Mass balance equations were written for each component in the system together with energy equation and implemented into the MATLAB Simulink simulation tool. Temperature, gas concentrations, pressure and current density were computed in the steady-state mode and validated against experimental data. The calculated I–V curve matched well the experimental one. In the dynamic modelling, several different conditions including step changes in fuel flow rates, stack voltage as well as temperature values were applied to estimate the system response against the load variations. Results provide valuable insight into the operating conditions that have to be achieved to ensure efficient CPOx  performance for fuel processing for the SOFC stack applications.
Źródło:
Polish Journal of Chemical Technology; 2016, 18, 4; 41-46
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Balance of cost, time, and quality related to construction projects regarding the reinforced concrete of underground structures using a meta-heuristic algorithm
Bilans kosztów, czasu i jakości w odniesieniu do projektów budowlanych dotyczących betonu zbrojonego w konstrukcjach podziemnych z wykorzystaniem algorytmu meta-heurystycznego
Autorzy:
Hosseini, S. A.
Akbarpour, A.
Ahmadi, H.
Aminnejad, B.
Powiązania:
https://bibliotekanauki.pl/articles/230342.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
konstrukcja podziemna
konstrukcja żelbetowa
zarządzanie projektem
bilans
koszt
czas
jakość
algorytm metaheurystyczny
algorytm genetyczny
underground structure
reinforced concrete structure
project management
balance
cost
time
quality
metaheuristic algorithm
genetic algorithm
Opis:
Underground spaces having features such as stability, resistance, and being undetected can play a key role in reducing vulnerability by relocating infrastructures and manpower. In recent years, the competitive business environment and limited resources have mostly focused on the importance of project management in order to achieve its objectives. In this research, in order to find the best balance among cost, time, and quality related to construction projects using reinforced concrete in underground structures, a multi-objective mathematical model is proposed. Several executive approaches have been considered for project activities and these approaches are analyzed via several factors. It is assumed that cost, time, and quality of activities in every defined approach can vary between compact and normal values, and the goal is to find the best execution for activities, achieving minimum cost and the maximum quality for the project. To solve the proposed multi-objective model, the genetic algorithm NSGA-II is used.
Pomysł stworzenia bezpiecznej przestrzeni ma na celu zmniejszenie lub wyeliminowanie skutków zniszczenia i promieniowania, ze względu na bombardowanie klasyczne lub jądrowe i inne ataki. W przypadku ataków lotniczych zwykle używa się bomb z ogromnym potencjałem wybuchu i siłą niszczycielską, a zatem zderzenie tych bomb z celami powstaje bardzo wysoki poziom energii kinetycznej. Ta energia kinetyczna rozchodzi się jako ciśnienie i ciepło w środowisku, co może zakłócić i zniszczyć cel. Czasem ochrona przed bombardowaniami w budynkach i obiektach jest zapewniona przez modernizację zapobiegającą bezpośredniemu uderzeniu. Odbywa się to w przypadku ważnych miejsc, takich jak stanowiska dowodzenia i kluczowe elementy infrastruktury. Jednakże, w innych przypadkach, jest to nieuzasadnione z ekonomicznego punktu widzenia, dlatego też zamiast tego często wykorzystuje się podziemne lub częściowo podziemne bezpieczne przestrzenie (Movahedinia [5]). Zarządzanie projektem to zorganizowany system służący do zarządzania zasobami, dzięki czemu projekt może być ukończony zgodnie z określoną wizją w zakresie jakości, czasu i kosztu (Burke [7]). Projekty budowlane, podobnie jak inne działania i projekty, posiadają swoje własne ograniczenia. W odniesieniu do zarządzania projektem, są to tradycyjnie ograniczenia zakresu, czasu i kosztu. Te trzy czynniki są również określane jako trójkąt zarządzania projektem, w którym każde ograniczenie określa jedną stronę trójkąta. Podobnie jak w geometrii, jeśli jedna strona ulegnie zmianie, inne strony również się zmieniają; w zarządzaniu projektem, zmiany jednego czynnika wpływają również na inne czynniki. Trójkąt zarządzania projektem można również stosować w relacjach czasu, kosztu i jakości (Clements i Gido [8]). Oznacza to, że każdy projekt posiada trzy ograniczenia, którymi są czas, koszt i zakres. Ogólnie rzecz biorąc, kwestia równoważenia kosztu, czasu i jakości jednocześnie stara się uwzględnić trzy ważne czynniki w zarządzaniu projektem. Łatwo zrozumieć, że kwestia ta ma charakter wieloczynnościowy i może być przedstawiana w postaci modeli o wielu celach (Shuquan i Kongguo [11]). Struktura takiego modelu zawiera wiele opcji dla każdego działania, a model próbuje wybrać te z minimalnym koszem i czasem oraz najwyższą maksymalną jakością, lecz w tym przypadku mamy do czynienia z równoważeniem selekcji, ponieważ wysoka jakość i szybkość mają swoją cenę, a wykonanie kosztownego projektu może nie być możliwe. Badanie to ma na celu modelowanie problemu równoważenia kosztu, czasu i jakości w formie problemu o wielu celach, a następnie jego rozwiązanie za pomocą meta-heurystycznych algorytmów.
Źródło:
Archives of Civil Engineering; 2017, 63, 4; 103-121
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flexoelectric and surface effects on a cracked piezoelectric nanobeam: Analytical resonant frequency response
Autorzy:
Bastanfar, M
Hosseini, S.A.H.
Sourki, R.
Khosravi, F.
Powiązania:
https://bibliotekanauki.pl/articles/140249.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
flexoelectricity
surface effects
imperfections
resonance frequency
nanobeam
Opis:
A nanoscale beam model containing defect under the piezoelectricity considering the surface effects and flexoelectricity is established on the framework of Euler-Bernoulli theory. The governing equations of motion and related boundary conditions are derived by using Hamilton’s principle. The imperfect nanobeam is modeled by dividing the beam into two separate parts that are connected by a rotational and a longitude spring at the defect location. Analytical results on the free vibration response of the imperfect piezoelectric nanobeam exhibit that the flexoelectricity and the surface effects are sensitive to the boundary conditions, defect position, and geometry of the nanobeam. Numerical results are provided to predict the mechanical behavior of a weakened piezoelectric nanobeam considering the flexoelectric and surface effects. It is also revealed that the voltage, defect severity, and piezoelectric material have a critical role on the resonance frequency. The work is envisaged to underline the influence of surface effects and flexoelectricity on the free vibration of a cracked piezoelectric nanobeam for diverse boundary conditions. It should be mentioned, despite our R. Sourkiprevious works, an important class of piezoelectric materials used nowadays and called piezoelectric ceramics is considered in the current study.
Źródło:
Archive of Mechanical Engineering; 2019, LXVI, 4; 417-437
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and Characterization of CuO Nanoparticles by the Chemical Liquid Deposition Method and Investigation of Its Catalytic Effect on the Thermal Decomposition of Ammonium Perchlorate
Autorzy:
Eslami, A.
Juibari, N. M.
Hosseini, S. G.
Abbasi, M.
Powiązania:
https://bibliotekanauki.pl/articles/358128.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
copper oxide nanoparticles
ex-situ growth
ammonium perchlorate
thermal decomposition
chemical liquid deposition
Opis:
Copper oxide nanoparticles have been synthesized by the chemical liquid deposition method and characterized by means of X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The XRD and SEM results showed that the particle size was between 50 nm and 70 nm. Ammonium perchlorate (AP)-CuO nanostructures have been prepared by ex-situ mixing of AP and CuO nanoparticles, while AP/CuO nanocomposites have been obtained by in-situ growth of nano CuO on the surface of AP. The effect of the nanoparticles on the thermal decomposition of AP has been examined by differential scanning calorimetery (DSC) and thermogravimetric analysis (TGA) methods. The results showed that the ex-situ prepared nanoparticles had better catalytic activity than the in-situ prepared ones. The effect of the synthesized nanoparticles on the thermal decomposition of AP in experiments with a AP to CuO ratio of 98:2 was as follows: with the ex-situ prepared experiments, the decomposition temperature decreased from 428 °C to 348 °C and the heat released increased from 344 J·g−1 to 1432 J·g−1, while those with the in-situ prepared samples exhibited 341 °C and 1317 J·g−1, respectively.
Źródło:
Central European Journal of Energetic Materials; 2017, 14, 1; 152-168
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exact solution for large amplitude flexural vibration of nanobeams using nonlocal Euler-Bernoulli theory
Autorzy:
Nazemnezhad, R.
Hosseini-Hashemi, S.
Powiązania:
https://bibliotekanauki.pl/articles/279261.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
nonlinear free vibration
nonlocal elasticity
nanobeam
exact solution
elliptic integrals
Opis:
In this paper, nonlinear free vibration of nanobeams with various end conditions is studied using the nonlocal elasticity within the frame work of Euler-Bernoulli theory with von K´arm´an nonlinearity. The equation of motion is obtained and the exact solution is established using elliptic integrals. Two comparison studies are carried out to demonstrate accuracy and applicability of the elliptic integrals method for nonlocal nonlinear free vibration analysis of nanobeams. It is observed that the phase plane diagrams of nanobeams in the presence of the small scale effect are symmetric ellipses, and consideration the small scale effect decreases the area of the diagram.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 2; 649-658
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł

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