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1.
Data Brief ; 48: 109269, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37383780

RESUMO

This data article presents a simulation model based on quantum mechanics and energy potentials for obtaining simulation data that allows, from the perspective of materials informatics, the prediction of the electrodeposition mechanism for forming nanostructured metallic coatings. The development of the research is divided into two parts i) the formulation (Quantum mechanical model and Corrected model for electron prediction; using a modified Schrödinger equation) and ii) the implementation of the theoretical prediction model (Discretization of the model). For the simulation process, the finite element method (FEM) was used considering the equation of electric potential and electroneutrality with and without the inclusion of quantum leap. We also provide the code to perform QM simulations in CUDA®, and COMSOL® software, the simulation parameters, and data for two metallic arrangements of chromium nanoparticles (CrNPs) electrodeposited on commercial steel substrate. (CrNPs-AISI 1020 steel and CrNPs-A618 steel). Data collection shows the direct relationship between applied potential (VDC), current (A), concentration (ppm), and time (s) for the homogeneous formation of the coating during the electrodeposition process, as estimated by the theoretical model developed. Their potential reuse data is done to establish the precision of the theoretical model in predicting the formation and growth of nanostructured surface coatings with metallic nanoparticles to give surface-mechanical properties.

2.
Chemosphere ; 266: 128968, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33246699

RESUMO

In the present study, microplastics (MPs) and metal concentrations were studied in the widely consumed tilapia (Oreochromis niloticus) fishes (n = 15) collected from a metropolitan reservoir of the Atoyac River basin, Mexico. Nearly 139 fibers were extracted from the gastrointestinal tracts and assessed using optical microscopy to evaluate their physical characteristics. The colour distribution of the fibers was mainly black (40%), blue (19%), red and white (14%). SEM images represented the surface morphology, while the elemental composition of the fibers was studied using EDX spectra. Polymer characterization using µFTIR aided in confirming the fibers as plastics (polyamide, polyester, and synthetic cellulose) and non-plastics (natural cellulose). Henceforth, ∼33% of the fibers, provisionally thought to be plastics, were natural fibers. The total metal concentrations were higher in the liver (259.24 mg kg-1) than the muscle (122.56 mg kg-1) due to diverse metabolic functions in the hepatic tissues. Human health risk assessment in terms of Hazard Index (HI) presented Pb and Zn values above unity in both adults and children, prompting regulatory measures. Statistical tests between MPs and fish biometry did not present any substantial correlations. The present study also affirmed that the presence of MPs and metals in fishes of a highly contaminated region is not only governed by their bioavailabilities, but also on the physiological characteristics of the individual organism.


Assuntos
Ciclídeos , Tilápia , Poluentes Químicos da Água , Animais , Criança , Monitoramento Ambiental , Água Doce , Humanos , México , Microplásticos , Plásticos , Poluentes Químicos da Água/análise
3.
J Nanosci Nanotechnol ; 9(3): 1935-41, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19435062

RESUMO

Bimetallic Pd/Pt nanoparticles were synthesized by bio-reduction method. The structural characterizations were performed by high resolution transmission electron microscope and energy dispersive spectroscopy. The size distribution, shapes, structures and elemental distribution were studied for the synthesized samples. Molecular simulation methods based on quantum mechanics have been applied to acquire the further information on their structural stability, electronic properties etc. The results show that the particle size for the pH = 4 was bimodal with an average particle size of 3.2 nm and a variance of 1.8 nm. While for pH is 7 the average is 3.9 nm about the variance increase up to 3.7 nm, and larger particles can be found. By the HREM micrographs, it is identified fcc-like clusters with a few planar defects, which may be pure Pd or Pt, or bimetallic Pd/Pt. Theoretically the most stable configuration corresponds to the Pd18Pt37 eutectic-like structure, which implies a cluster in cluster form.


Assuntos
Nanopartículas Metálicas , Microscopia Eletrônica de Transmissão , Paládio/química , Platina/química , Simulação por Computador , Concentração de Íons de Hidrogênio , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Modelos Químicos , Modelos Moleculares , Termodinâmica
4.
J Nanosci Nanotechnol ; 6(1): 151-6, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16573087

RESUMO

The bio-reduction method is reported as a part of a complimentary self-sustained technology, where bioremediation and metal particle production are related. The use of the characterization methods in this self sustainable technique open the expectative to be used for several other elements and with other plants, which will be discussed. However, the particular case of Mn nanoparticles involves an important option to generate nanoparticles in the range of 1-4 nanometers with a well controlled size and with a structure based on an fcc-like geometry for the smallest clusters and with more complex arrays for cluster greater than four shells, which involves magnetic moments significantly related to their atomistic configuration. At the same time, the use of the characterization methods establishes the dependence of the nanoparticle's size on the pH conditions used during the synthesis; small clusters in the range of 1-2 nm were generated using pH=5, and it was shown that for the smallest aggregates, simple polyhedron shapes are stable.


Assuntos
Eichhornia/química , Manganês/química , Biomassa , Eichhornia/ultraestrutura , Microscopia Eletrônica , Microscopia Eletrônica de Varredura , Nanoestruturas/química , Oxirredução , Teoria Quântica
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