A protocol for size separation of nanographenes

There has been a growing public health issue concerning the regulation of indoor air quality (IAQ) and the human exposure to particulate matter (PM). Today, this exposure is a major worldwide concern because ambient PM concentrations in many cities exceeded the limits set by the European air quality directive. Underground airborne particles are mainly generated by the mechanical abrasion of rail tracks, wheels and brake pads produced by urban railways transportation. For that reason, understanding the transport mechanism of particles with various size distribution is essential and crucial for understanding and accurately predicting the behavior of the main high particle concentration areas. In this framework, a simple case of particles emission inside a viscous flow in a channel has been investigated both experimentally and numerically. The suspended particles used experimentally are molybdenum solid particles with a broad size distribution (in diameter) from 1 to 80 μm (size similar to cases such as in braking systems). The experimental tests are conducted for a flow in a channel at a horizontal steady inflow velocity of uf = 0.15m/s. The solid particles are injected transversely to the horizontal bottom wall with an injection steady velocity of ui = 0.95m/s. Measurements and analysis are carried out using shadowscopy technique to determine the particles concentration fields. Finally, experimental results are compared to numerical ones predicted by a continuum computational fluid dynamics (CFD) approach using the SBM (Suspension Balance Model) implemented in “OPENFOAM” (via the Finite Volume Method).

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Control over the Biological Synthesis of Ag Nanoparticles by Selection of the Specific Algal Species

Archives of Metallurgy and Materials ◽

10.1515/amm-2017-0222 ◽

2017 ◽

Vol 62 (3) ◽

pp. 1439-1442

Author(s):

J. Sedlakova-Kadukova ◽

O. Velgosova ◽

M. Vosatka ◽

J. Lukavsky ◽

J. Dodd ◽

...

Keyword(s):

Size Distribution ◽

Algal Species ◽

Biological Synthesis ◽

Transmission Electron ◽

Broad Size Distribution ◽

Vis Spectroscopy ◽

Parachlorella Kessleri ◽

Long Time ◽

Nano Science ◽

Selection Of

AbstractThe application of green synthesis in the nano-science and technology is of great importance in the area of the preparation of various materials. In this work, three selected algal species Parachlorella kessleri, Dictyosphaerium chlorelloides and Desmodesmus quadricauda were successfully used for the preparation of silver nanoparticles (AgNPs). Presence of AgNPs was confirmed by UV-vis spectroscopy and transmission electron microscopy. AgNPs produced by P. kessleri had narrow size distribution and average sizes of 7.6 nm. However, nanoparticle production lasted for long time. Nanoparticle formation by D. chlorelloides was the fastest, although, their average sizes were 23.4 nm with broad size distribution. Nanoparticles produced by D. quadricauda had average sizes 23.9 nm but they were the least stable, aggregated and precipitated from solutions within 3 days. These results confirmed that the size distribution and mean diameter of the nanoparticles, crucial for various applications, can be controlled by the organism selection.

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Effectiveness of the Top-Down Nanotechnology in the Production of Ultrafine Cement (~220 nm)

Journal of Nanomaterials ◽

10.1155/2014/131627 ◽

2014 ◽

Vol 2014 ◽

pp. 1-9 ◽

Cited By ~ 7

Author(s):

Byung-Wan Jo ◽

Sumit Chakraborty ◽

Ki Heon Kim ◽

Yun Sung Lee

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

Milling Process ◽

Sustainable Construction ◽

Cement Particle ◽

Top Down ◽

Bead Milling ◽

Grinding Time ◽

Ultrafine Cement

The present investigation is dealing with the communition of the cement particle to the ultrafine level (~220 nm) utilizing the bead milling process, which is considered as a top-down nanotechnology. During the grinding of the cement particle, the effect of various parameters such as grinding time (1–6 h) and grinding agent (methanol and ethanol) on the production of the ultrafine cement has also been investigated. Performance of newly produced ultrafine cement is elucidated by the chemical composition, particle size distribution, and SEM and XRD analyses. Based on the particle size distribution of the newly produced ultrafine cement, it was assessed that the size of the cement particle decreases efficiently with increase in grinding time. Additionally, it is optimized that the bead milling process is able to produce 90% of the cement particle<350 nm and 50% of the cement particle<220 nm, respectively, after 6.3 h milling without affecting the chemical phases. Production of the ultrafine cement utilizing this method will promote the construction industries towards the development of smart and sustainable construction materials.

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Improving the Size Homogeneity of Multicore Superparamagnetic Iron Oxide Nanoparticles

International Journal of Molecular Sciences ◽

10.3390/ijms21103476 ◽

2020 ◽

Vol 21 (10) ◽

pp. 3476

Author(s):

Barry J. Yeh ◽

Tareq Anani ◽

Allan E. David

Keyword(s):

Magnetic Field ◽

Iron Oxide ◽

Size Distribution ◽

Iron Oxide Nanoparticles ◽

Scale Up ◽

Superparamagnetic Iron Oxide ◽

Superparamagnetic Iron Oxide Nanoparticles ◽

P Value ◽

Oxide Nanoparticles ◽

Broad Size Distribution

Superparamagnetic iron oxide nanoparticles (SPIONs) have been widely explored for use in many biomedical applications. Methods for synthesis of magnetic nanoparticle (MNP), however, typically yield multicore structures with broad size distribution, resulting in suboptimal and variable performance in vivo. In this study, a new method for sorting SPIONs by size, labeled diffusive magnetic fractionation (DMF), is introduced as an improvement over conventional magnetic field flow fractionation (MFFF). Unlike MFFF, which uses a constant magnetic field to capture particles, DMF utilizes a pulsed magnetic field approach that exploits size-dependent differences in the diffusivity and magnetic attractive force of SPIONs to yield more homogenous particle size distributions. To compare both methods, multicore SPIONs with a broad size distribution (polydispersity index (PdI) = 0.24 ± 0.05) were fractionated into nine different-sized SPION subpopulations, and the PdI values were compared. DMF provided significantly improved size separation compared to MFFF, with eight out of the nine fractionations having significantly lower PdI values (p value < 0.01). Additionally, the DMF method showed a high particle recovery (>95%), excellent reproducibility, and the potential for scale-up. Mathematical models were developed to enable optimization, and experimental results confirmed model predictions (R2 = 0.98).

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Polyethylene Glycol Diacrylate Microgels from Irradiated Micelles

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1024.316 ◽

2014 ◽

Vol 1024 ◽

pp. 316-319 ◽

Cited By ~ 3

Author(s):

Hamzah Yusof ◽

Mat Isa Naurah ◽

Mohd Ali Napia Liyana

Keyword(s):

Molecular Weight ◽

Electron Beam ◽

Polyethylene Glycol ◽

Size Distribution ◽

Drug Carriers ◽

Blood Stream ◽

Beam Radiation ◽

Polyethylene Glycol Diacrylate ◽

Glycol Diacrylate ◽

Broad Size Distribution

Micro sized gels have been widely used as drug carriers for its compatibility in blood. Among its important properties are round small dimensions and large surface area. These properties allow for better attachment of ligand and higher stability in the blood stream. In this study,microgels from polyethylene glycol diacrylate (PEGDA) were prepared from its microemulsions form using electron beam with energy of 3 MeVat different irradiation dose of 0 to 25 kGy. Dynamic light scattering (DLS) study revealed that gel with diameter of 70-100 nm with a narrow size distribution was obtained at 5 kGy and 400-550 nm with a broad size distribution at 25 kGy. The molecular weight obtained from GPC-MALLS for the minimum practical dose irradiated has resulted to more than 4.22 x 105 g/mol as compared to7.75 x 102 g/mol forunirradiated polymer. The increase of size and its distribution as well as its molecular weight over the elevation dose were suspected to be due to diffusion of micelles that leads to recombination of macro radicals from different micelles during longer irradiation period at higher doses. Overall findings from this study have proven that PEGDA microgels can be prepared via electron beam radiation with emulsions as templates for polymerization.

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Powder Characterization and Electrochemical Properties of LiNi0.5Mn1.5O4Cathode Materials Produced by Large Spray Pyrolysis Using Flame Combustion

Advances in Materials Science and Engineering ◽

10.1155/2011/768143 ◽

2011 ◽

Vol 2011 ◽

pp. 1-6 ◽

Cited By ~ 7

Author(s):

Shinsuke Akao ◽

Motofumi Yamada ◽

Takayuki Kodera ◽

Kenichi Myoujin ◽

Takashi Ogihara

Keyword(s):

Spray Pyrolysis ◽

Size Distribution ◽

Discharge Capacity ◽

Average Diameter ◽

Cycle Performance ◽

Narrow Particle Size Distribution ◽

Capacity Retention ◽

Flame Combustion ◽

Broad Size Distribution ◽

Porous Microstructure

LiNi0.5Mn1.5O4cathode materials were produced by spray pyrolysis apparatus using the flame combustion. SEM revealed that as-prepared powders had spherical morphology with porous microstructure which had an average diameter of about 2 μm with broad size distribution. After the calcination, LiNi0.5Mn1.5O4powders with polygonal morphology and narrow particle size distribution were obtained. XRD showed that LiNi0.5Mn1.5O4was well crystallized after the calcination at 900°C. Rechargeable measurement of LiNi0.5Mn1.5O4cathode showed that the long plateau was observed at 4.7 V in discharge curve of LiNi0.5Mn1.5O4cathode and its discharge capacity was 145 mAh/g at 1 C. The capacity retention of LiNi0.5Mn1.5O4cathode were 95% at 1 C after 100 cycles. The discharge capacity and capacity retention of LiNi0.5Mn1.5O4cathode were 125 mAh/g and 88% at 20 C. LiNi0.5Mn1.5O4cathode exhibited also stable cycle performance at 50C.

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Preparation of Submicron Silica Powders from Sodium Silicate Using Ultrasonic Energy

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.920 ◽

2007 ◽

Vol 336-338 ◽

pp. 920-923

Author(s):

Sang Geun Lee ◽

Yoon Sik Jang ◽

Seong Soo Park ◽

Byung Young Moon ◽

Beom Soo Kang ◽

...

Keyword(s):

Particle Size ◽

Low Temperature ◽

Particle Size Distribution ◽

Size Distribution ◽

Sodium Silicate ◽

Narrow Size Distribution ◽

Emulsion Method ◽

Conventional Process ◽

Broad Size Distribution ◽

Ultrasonic Process

Submicron silica powders were prepared by w/o emulsion method using inexpensive sodium silicate, ammonium sulfate and Triton N-57 as SiO2 source, precipitant and emulsifier, respectively. Nano-sized silica powders with narrow size distribution were prepared at a low temperature of 25°C for 1h by ultrasonic irradiation of the reactants using a commercial ultrasonic cleaner operating at a frequency of 47kHz, whereas silica powders with larger size and broad size distribution were synthesized using the same reactants at the same temperature and for the same time by the conventional process without ultrasounds. The particle size and size distribution of the silica powders obtained by the ultrasonic process were smaller and narrower than those by the conventional process, indicating that the application of ultrasound in the synthesis of silica powders by the w/o emulsion method is an efficient way to have powders with smaller and narrower particle size distribution.

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