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1.
J Chem Phys ; 160(19)2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38747430

RESUMO

In this research, thermal modeling has been done to investigate the effect of nanofluid on the performance of the linear parabolic collector. Therminol vapor/liquid phase fluid (VP-1) has been used as a base fluid; iron oxide nanoparticles have been used to produce mono-nanofluid; and iron oxide multi-walled carbon nanotubes nanocomposite has been used as nanoparticles to produce hybrid nanofluid. The fluid flow inside the absorber tube of the collector is assumed to be turbulent. The results show that when hybrid nanofluid and mono-nanofluid are used, the energy and exergy efficiencies of the collector are higher than those for the conditions of using the base fluid, but their amount is slightly lower with the use of hybrid nanofluid than when the working fluid is mono-nanofluid. According to the obtained results, the highest energy efficiency of the linear parabolic collector using nanofluid and mono-nanofluid is 70.2% and 70.4%, respectively, and the highest exergy efficiency is 35.7% and 35.9%, respectively. Despite this, the friction coefficient of mono-nanofluid compared to hybrid nanofluid was obtained on average about 9% higher. The results showed that the criterion for evaluating the performance of the collector (hydrodynamic thermal efficiency) when hybrid nanofluid is used is more than when mono-nanofluid is used.

2.
J Chem Phys ; 159(17)2023 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-37929868

RESUMO

Polymer membrane electrolyzers are a useful tool for producing hydrogen, which is a renewable energy source. Unmanned aerial vehicle (UAV) fuel cells can be powered by the hydrogen and oxygen produced by the electrolyzer. The primary losses of polymer membrane electrolyzers must therefore be identified in order to maximize their performance. A renewable-based multi-energy system considers power, cooling, heating, and hydrogen energy as utility systems for integrated sport buildings. In this study, we investigate the effect of radiation intensity, current density, and other performance factors on the rate of hydrogen production in water electrolysis using a polymer membrane electrolyzer in combination with a solar concentrator. The findings showed that a rise in hydrogen generation led to an increase in current density, which increased the electrolyzer's voltage and decreased its energy and exergy efficiencies. The voltage was also increased, and the electrolyzer's efficiency was enhanced by a rise in temperature, a decrease in pressure, and a reduction in the thickness of the nafion membrane. Additionally, with a 145% increase in radiation intensity, hydrogen production increased by 110% while the electrolyzer's energy and exergy efficiencies decreased by 13.8% as a result of the electrolyzer's high input electric current to hydrogen output ratio.

3.
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1354921

RESUMO

Objetivo: La dopamina y la serotonina son los dos importantes transmisores biológicos que tienen actividades hormonales y son responsables de la felicidad y el bienestar. El objetivo de este artículo fue estudiar teóricamente las características estructurales de la dopamina y la serotonina en el complejo de nanotubos de carbono de pared simple como neurotransmisor. Material y métodos: Se estudió la estructura de la unión de dopamina y serotonina con SWCNT con cuatro diámetros diferentes (7.0, 7.5, 7.7, 10.0 nm) utilizando mecánica molecular (MM) y mecánica cuántica (QM). Las energías notables, incluida la energía potencial, la energía total y la energía cinética en el tiempo de simulación en pasos de 10 ns en dos temperaturas (298, 310 grados kelvin), fueron investigadas por el método de Monte Carlo con fuerza opls archivada. También se han cumplido los datos del tensor de blindaje de RMN según el nivel de teoría B3LYP con 6-31 G (d) como conjunto de base y método semi empírico. Resultados: Se realizaron cálculos teóricos para estudiar los datos de desplazamiento químico de RMN, incluido el tensor de blindaje magnético (σ, ppm), la asimetría de blindaje (η), la anisotropía de blindaje magnético (σaniso), la isotropía de blindaje magnético (σiso), la desviación de un tensor (Κ) y anisotropía de desplazamiento químico (Δσ) y span (Ω) en varios ángulos de rotación alrededor de una rotación específica, propiedades físicas y químicas de los núcleos atómicos. Se revelaron cálculos semi empíricos como energía total, energía de enlace, energía atómica aislada, energía electrónica, interacción núcleo-núcleo y calor de formación en Am1. Conclusión: En el método Monte Carlo se deduce que nuestros dos fármacos específicos y su nanotubo de pequeño diámetro son los más estables que los demás. El diámetro más grande lleva la estabilidad de la combinación a un valor más bajo.


Objetive:Dopamine and Serotonin are the two important biological transmitters that have hormonal activities and responsible for happiness and felling well. The aim of this article was to study theoretically the structure features of Dopamine and Serotonin in the complex of single-walled carbon nanotube as a neurotransmitter. The structure of Dopamine and Serotonin binding with Material and Methods:SWCNTwith four different diameters (7.0,7.5,7.7,10.0 nm) was studied by using molecular mechanic (MM) and quantum mechanic (QM). The remarkable energies including potential energy, total energy and kinetic energy in time of simulation 10 ns steps in two temperatures (298, 310 kelvin degree) were investigated by Monte Carlo method with opls force filed. NMR shielding tensor data by B3LYPlevel of theory with 6-31 G(d) as a basis set and semi empirical method have been also fulfilled.Results: Theoretical computations were performed to study NMR chemical shift data including magnetic shielding tensor (σ, ppm), shielding asymmetry (η), magnetic shielding anisotropy (σaniso), magnetic shielding isotropy (σiso) , skew of a tensor (Κ) and chemical shift anisotropy (Δσ) and span (Ω) at various rotation angles around a specific rotation, physical and chemical properties of atomic nuclei. Semi empirical calculations such as total energy, binding energy, isolated atomic energy, electronic energy, core­core interaction and heat of formation in AM1 were revealed. It is figured out Conclusion:in Monte Carlo method our two specific drug and its nanotube with small diameter are the most stable one than the others. The larger diameter leads the combination stability into lower value

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