scholarly journals Preparation of W-C-Co Composite Micropowder with Spherical Shaped Particles Using Plasma Technologies

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4258
Author(s):  
Andrey Samokhin ◽  
Nikolay Alekseev ◽  
Aleksey Astashov ◽  
Aleksey Dorofeev ◽  
Andrey Fadeev ◽  
...  
Keyword(s):  
Particle Size ◽  
Plasma Treatment ◽  
Average Particle Size ◽  
Spherical Particles ◽  
Average Particle ◽  
Dense Microstructure ◽  
Scale Range ◽  
Powder Particles ◽  
Phase And Chemical Composition ◽  
Average Size

The possibility of obtaining composite micropowders of the W-C-Co system with a spherical particle shape having a submicron/nanoscale internal structure was experimentally confirmed. In the course of work carried out, W-C-Co system nanopowders with the average particle size of approximately 50 nm were produced by plasma-chemical synthesis. This method resulted in the uniform distribution of W, Co and C among the nanoparticles of the powder in the nanometer scale range. Dense microgranules with an average size of 40 microns were obtained from the nanopowders by spray drying. The spherical micropowders with an average particle size of 20 microns were received as a result of plasma treatment of 25.36 microns microgranule fraction. The spherical particles obtained in the experiments had a predominantly dense microstructure and had no internal cavities. The influence of plasma treatment process parameters on dispersity, phase, and chemical composition of spherical micropowders and powder particles microstructure has been established.

scholarly journals Effect of the polymeric coating over Fe3O4 particles used for magnetic separation

2010 ◽  
Vol 8 (5) ◽  
pp. 1041-1046 ◽  
Author(s):  
Raúl Reza ◽  
Carlos Martínez Pérez ◽  
Claudia Rodríguez González ◽  
Humberto Romero ◽  
Perla García Casillas
Keyword(s):  
Particle Size ◽  
Magnetite Nanoparticles ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Polymeric Coating ◽  
Average Particle ◽  
Synthesis Conditions ◽  
Aging Conditions ◽  
Magnetite Particles ◽  
Average Size

AbstractIn this work, the synthesis of magnetite nanoparticles by two variant chemical coprecipitation methods that involve reflux and aging conditions was investigated. The influence of the synthesis conditions on particle size, morphology, magnetic properties and protein adsorption were studied. The synthesized magnetite nanoparticles showed a spherical shape with an average particle size directly influenced by the synthesis technique. Particles of average size 27 nm and 200 nm were obtained. When the coprecipitation method was used without reflux and aging, the smallest particles were obtained. Magnetite nanoparticles obtained from both methods exhibited a superparamagnetic behavior and their saturation magnetization was particle size dependent. Values of 67 and 78 emu g−1 were obtained for the 27 nm and 200 nm magnetite particles, respectively. The nanoparticles were coated with silica, aminosilane, and silica-aminosilane shell. The influence of the coating on protein absorption was studied using Bovine Serum Albumin (BSA) protein.

scholarly journals Preparation, Characterization, and In Vivo Pharmacokinetic Study of the Supercritical Fluid-Processed Liposomal Amphotericin B

Pharmaceutics ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 589 ◽  
Author(s):  
Chang-baek Lim ◽  
Sharif Md Abuzar ◽  
Pankaj Ranjan Karn ◽  
Wonkyung Cho ◽  
Hee Jun Park ◽  
...  
Keyword(s):  
Particle Size ◽  
Amphotericin B ◽  
Supercritical Fluid ◽  
Liposomal Amphotericin ◽  
Average Particle Size ◽  
Spherical Particles ◽  
Liposomal Amphotericin B ◽  
Average Particle ◽  
In Vivo Pharmacokinetics

Here, we aimed to prepare and optimize liposomal amphotericin B (AmB) while using the supercritical fluid of carbon dioxide (SCF-CO2) method and investigate the characteristics and pharmacokinetics of the SCF-CO2-processed liposomal AmB. Liposomes containing phospholipids, ascorbic acid (vit C), and cholesterol were prepared by the SCF-CO2 method at an optimized pressure and temperature; conventional liposomes were also prepared using the thin film hydration method and then compared with the SCF-CO2-processed-liposomes. The optimized formulation was evaluated by in vitro hemolysis tests on rat erythrocytes and in vivo pharmacokinetics after intravenous administration to Sprague-Dawley rats and compared with a marketed AmB micellar formulation, Fungizone®, and a liposomal formulation, AmBisome®. The results of the characterization studies demonstrated that the SCF-CO2-processed-liposomes were spherical particles with an average particle size of 137 nm (after homogenization) and drug encapsulation efficiency (EE) was about 90%. After freeze-drying, mean particle size, EE, and zeta potential were not significantly changed. The stability study of the liposomes showed that liposomal AmB that was prepared by the SCF method was stable over time. In vivo pharmacokinetics revealed that the SCF-CO2-processed-liposomes were bioequivalent to AmBisome®; the hemolytic test depicted less hematotoxicity than Fungizone®. Therefore, this method could serve as a potential alternative for preparing liposomal AmB for industrial applications.

Preparation of Cr2O3 Nanoparticles via Hydrothermal Reduction of CH3OH

2012 ◽  
Vol 463-464 ◽  
pp. 760-763
Author(s):  
Zhen Zhao Pei ◽  
Hong Bin Xu ◽  
Yi Zhang
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Average Particle Size ◽  
Average Particle ◽  
Calcination Temperatures ◽  
Cr2o3 Nanoparticles ◽  
Average Size ◽  
Hydrothermal Reduction ◽  
Scanning Electron

Nanoparticles of Cr2O3 were successfully obtained via hydrothermal reduction of CH3OH. The oxidant and chromium source was CrO3. The process needs no stirrer or surfactant and the CrO3 concentration was 0.83mol/L. The obtained products were loosely agglomerated Cr2O3 nanoparticles with the average size of 29 to 79 nm. Influences of reactant ratios and calcination temperatures on the specific surface area and average particle size were discussed. And the morphology of nanoparticles was investigated by use of field-emission scanning electron microscope.

Investigating the Structure and Properties of the AlSi10Mg Alloy Manufactured by Means of Selective Laser Melting

2020 ◽  
pp. 71-85
Author(s):  
A.K. Karavaev ◽  
Yu.A. Puchkov
Keyword(s):  
Particle Size ◽  
Heat Affected Zone ◽  
Average Particle Size ◽  
Average Particle ◽  
General Corrosion ◽  
Pure Aluminium ◽  
Structure And Properties ◽  
Columnar Crystal ◽  
Sample Depth ◽  
Powder Particles

The paper investigates the structure and properties of samples made of ASP-25 AlSi10Mg, a Russian powder designed to replace expensive additive manufacturing powders of European origin featuring the same chemical composition. We detected that the particle size in the ASP-25 AlSi10Mg powder varies in the range of 7 to 50 μm, the average particle size being 23 μm for the standard deviation of 9.15 and dispersion of 83.7. On the surface of powder particles, we observed smaller satellite particles, individual aggregates, and particles of pure aluminium. We detected the following at the transition boundary between adjacent tracks: a columnar crystal zone and a heat-affected zone consisting of three layers of large, medium and small grains generated as a result of varied cooling conditions. These grains display different silicon lattice thicknesses along their boundaries. We detected no critical size pores (over 15 μm) or burning in the heat-affected zone. The fact that microhardness increases towards the sample edges and is non-monotonic over the transverse section is due to a range of factors acting simultaneously to create non-uniform temperature and force fields that cause differences in conditions of structure formation. Fractography studies of fractures in the AlSi10Mg alloy showed that the nature of failure varies along the sample depth. The central part of the sample, which is subjected to the highest thermal effects, shows clear signs of viscous failure along the main cracks developing along the boundaries of construction layers. We showed that the AlSi10Mg alloy is more resistant to pitting corrosion and general corrosion than the AK9сh (AK9ч) alloy

Synthesis of Nano-Sized Barium Titanate Powder by Rotary-Hydrothermal Process

2009 ◽  
Vol 421-422 ◽  
pp. 269-272
Author(s):  
Takashi Kubo ◽  
Masayuki Hogiri ◽  
Hiroshi Kagata ◽  
Atsushi Nakahira
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Hydrothermal Process ◽  
Water System ◽  
Starting Material ◽  
Average Particle ◽  
Rotary Speed ◽  
Average Size ◽  
Faceted Particles

Nano-sized BaTiO3 powders with narrow size distribution and the high tetragonality were attempted to synthesize by the rotary-hydrothermal process in water system, using two kinds of commercial anatase-type TiO2 (ST21/ST01) with different particle size and Ba(OH)2. The rotary-hydrothermal syntheses were done with the rotary-speed of 20 revolutions per minute at 523 K for 24 h. Highly- and mono-dispersed BaTiO3 powders were successfully synthesized by applying the rotary-hydrothermal process. For rotary-hydrothermal synthesis, it was found that the average size, tetragonality, and quality of the BaTiO3 particle strongly depended on the particle size of the starting material. In the case of using ST01 as a starting material, BaTiO3 nano-powders mainly composed of coarse-faceted particles (average particle size = ca.100 nm) with the tetragonal phase and very little lattice defects were successfully synthesized.

Effect of Surfactant on the Preparation of Nano-powder for Yb Doping Laser Transparent YAG Ceramic

2013 ◽  
Vol 32 (5) ◽  
pp. 511-515 ◽  
Author(s):  
Xiao Guo Cao ◽  
Jia Wang ◽  
Qi Bai Wu ◽  
Hai Yan Zhang
Keyword(s):  
Particle Size ◽  
Polyethylene Glycol ◽  
Average Particle Size ◽  
Ammonium Bicarbonate ◽  
Spherical Particles ◽  
Precipitation Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Nano Powder ◽  
Co Precipitation

AbstractYb:YAG transparent ceramic nano-powder was prepared by chemical co-precipitation method, with ammonium bicarbonate as the precipitant and polyethylene glycol as surfactant. The addition of polyethylene glycol can reduce the agglomeration and particle size of the prepared Yb:YAG powder. The morphology, thermal stability and phase structure of Yb:YAG nano-powder were charactered by scanning electron microscopy (SEM), thermogravimetry and differential thermal analysis (TG-DTA), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy. The results show that well-crystallized nano-powder was obtained by calcining the precursors at 900 °C for 3 h. The average particle size of Yb:YAG powder is about 100–200 nm. When the volume amount of polyethylene glycol is 2.0%, well-dispersed Yb:YAG powder with spherical particles of 100 nm diameter was obtained.

Preparation and Characterization of Gold Nanoparticles in the Presence of Citrate and Soybean Seed Extract in an Acidic Conditions

Drug Research ◽  
2017 ◽  
Vol 67 (05) ◽  
pp. 266-270 ◽  
Author(s):  
Ebrahim Izadi ◽  
Ali Rasooli ◽  
Abolfazl Akbarzadeh ◽  
Soodabeh Davaran
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Size Distribution ◽  
Average Particle Size ◽  
Soybean Seed ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Soybean Extract ◽  
Average Size

AbstractThrough the present study, an eco-friendly method was used to synthesize the gold nanoparticles (GNPs) by using the sodium citrate and extract of the soybean seed as reducing the agents at PH 3. X-Ray diffraction (XRD) method was used to evaluate the crystal structure of as-synthesized NPs and it’s revealed that this method leads to well crystallized GNPs. In order to determine the particle size and their distribution, field emission scanning microscopy (FE-SEM) and dynamic light scattering (DLS) were used. The results showed that, the average particle size distribution of synthesized GNPs in solutions containing of the soybean extract and 1% citrate at PH 3 is about 109.6 and 140.9 nm, respectively. Also, we find that the average size of GNPs is 40 and 33 nm from solutions of citrate and soybean extract, respectively. It was concluded that using the extract of soybean seeds as reducing agent can lead to GNPs with small size and narrow size distribution.

scholarly journals Application of surfactants for the synthesis of qualitative hydroxide and metallic cobalt nanopowders

2021 ◽  
pp. 4-11
Author(s):  
Van Minh Nguyen ◽  
Tien Hiep Nguyen ◽  
Stanislav V. Gorobinsky
Keyword(s):  
Particle Size ◽  
Hydrogen Reduction ◽  
Cetylpyridinium Chloride ◽  
Average Particle Size ◽  
Sodium Dodecyl ◽  
Chemical Precipitation ◽  
Spherical Particles ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Application Of Surfactants

In this work, nanopowders (NP) Co(OH)2 were obtained by chemical precipitation from aqueous solutions of cobalt nitrate Co(NO3)2 and alkali NaOH (10 wt. %) using surfactants: sodium dodecyl sulfate (SDS) and cetylpyridinium chloride (CPC) (0.1 wt. %). It was shown that Co(OH)2 NP with 0.1% SDS is the best quality product, since its dispersion increases more than 2 times compared to the samples with 0.1% CPC and without surfactants. In this case, the Co(OH)2 NP has the form of flakes with an irregular shape and a nanometer size (about 100 nm) with an average thickness of 30 nm. It was found that the average particle size of Co NP obtained by hydrogen reduction of Co(OH)2 NP with 0.1% SDS at 280°C has a maximum on the distribution histogram shifted to the interval 41–50 nm, which is characterized by a narrow particle size distribution and represents spherical particles sintered with each other.

scholarly journals STUDY PARTICLE SIZE DISTRIBUTION OF ERODING POWDER LEAD BRONZES OBTAINED IN DISTILLED WATER

2018 ◽  
Vol 22 (4) ◽  
pp. 42-49
Author(s):  
E. V. Ageev ◽  
A. S. Pereverzev ◽  
A. S. Osminina ◽  
I. Yu. Grigorov
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Discharge Zone ◽  
Powder Materials ◽  
Average Particle ◽  
Distilled Water ◽  
Powder Particles ◽  
Local Exposure ◽  
Finely Dispersed Powder ◽  
Powder Lead

The article is devoted to the current problem of processing waste of conductive materials, in particular lead bronze, which accumulates in large quantities at enterprises. A promising method for processing any conductive material, characterized by wastelessness, ecological purity of the process, and low energy costs, is the method of electroerosive dispersion. The essence of the method of electroerosive dispersion is the destruction of current-conducting material as a result of local exposure to short-term electrical discharges between the electrodes. In the discharge zone, under high temperatures, heating, melting and partial evaporation of the material occurs, resulting in the formation of finely dispersed powder particles. At the same time, the electrical parameters of the installation will affect the productivity of the process for obtaining powder materials: the voltage at the electrodes, the capacitance of the discharge capacitors, and the repetition rate. The article presents the results of the analysis of particles of powdered lead bronze obtained by the method of electroerosive dispersion in distilled water from wastes, using the laser analyzer of particle sizes "Analysette 22 NanoTec". It has been experimentally established that the average particle size of powdered lead bronze is 9.73 μm, the arithmetic value is 9.731 μm. It was also found that the elongation coefficient (elongation) of particles with a size of 7.188 μm is 1.50.

scholarly journals Design of a Reversible Cholinesterase Inhibitor Mamentine HCL Nanogel: Formulation and In-vitro Evaluation

2021 ◽  
pp. 352-359
Author(s):  
Subhasri Mohapatra ◽  
Sourabh Jain ◽  
Karunakar Shukla
Keyword(s):  
Particle Size ◽  
Cholinesterase Inhibitor ◽  
Average Particle Size ◽  
In Vitro Release ◽  
Storage Period ◽  
Spherical Particles ◽  
Average Particle ◽  
In Situ Gel

Memantine hydrochloride is a is a reversible cholinesterase inhibitor used in the treatment of Alzheimer’s disease, low-moderate affinity, uncompetitive n-methyl-d-aspartate (NMDA) receptor antagonist, with strong voltage dependency and rapid blocking/unblocking kinetics. The present study was explore the potential of thermosensitive nanogel of mamentine loaded nanoparticle. In situ gel choosing due to restrict unwanted exposure in blood and other healthy tissues, thus eliminate hemolytic side effects of the drug and offer easy administration in vivo. Nanoparticle prepared by ionic gelation method and further the dried nanoparticle incorporates with in situ gel.  The in situ gel prepared by cold method using the solutions of Poloxamer-188 and Carbopol-934. The Transmission electron microscopy showed the spherical particles  with  smooth surface which was in conformity  with the SEM and Zetasizer  data for particle size. The pH of the formulations was found to be satisfactory and was in the range of 6.8±0.039 -7.4±0.053 and also mucoadhesive strength was show in table. The mucoadhesive strength of all formulations was varies from 2398±0.0004 to 4945±0.0002 dynes/cm2. In-vitro diffusion study of the in situ gel (N1-N8) was performed using modified Franz diffusion cell with dialysis membrane in phosphate buffer pH 6.5 for a period of 24 hours. The in vitro release study were fitted into various kinetic models viz zero order, first order, higuchi model and korsmeyer peppas equation. Stability studies for optimized formulations were carried out at 4.0 ± 0.5°C and 37 ± 0.5ºC for a period of four weeks. There was no significant variation found in physical appearance, average particle size and % drug content of the in situ nanogel N2. No visible changes in the appearance of the gel formulation were observed at the end of the storage period.

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