scholarly journals Green Synthesis and the Study of Some Physical Properties of MgO Nanoparticles and Their Antibacterial Activity

2020 ◽  
pp. 266-276
Author(s):  
Rand Ali ◽  
Zainab Jassim ◽  
Ghada Muhammad Saleh ◽  
Quraysh Abass
Keyword(s):  
Particle Size ◽  
Antibacterial Activity ◽  
Energy Gap ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Magnesium Nitrate ◽  
Average Particle ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Impact

     Magnesium oxide nanoparticles (MgO NPs) were synthesized by a green method using the peels of Persimmon extract as the reducing agent , magnesium nitrate, and NaOH. This method is eco-friendly and non-toxic. In this study, an ultrasound device was used to reduce the particle size, with the impact on the energy gap was set at the beginning at 5.39 eV and then turned to 4.10 eV. The morphological analysis using atomic force microscopy (AFM)  showed that the grain size for MgO NPs was 67.70 nm which became 42.33 nm after the use of the ultrasound. The shape of the particles was almost spherical and became cylindrical.  In addition the Field-Emission Scanning Electron Microscopy (FESEM) analysis showed that the average particle size was reduced and the spherical shape was changed into cylindrical flakes. The antibacterial activity of MgO Nps was measured against both gram positive and negative bacteria (Staphylococcus aureus and Escherichia coli, respectively) for both the synthesized and the scaled-down particles by the ultrasonic. MgO NPs showed an efficacy at a minimum inhibitory concentration (MIC) of 500 μg/ml, with the better effect being observed after the ultrasonic treatment of the MgO NPs.

scholarly journals Effective Method for Obtaining the Hydrosols of Detonation Nanodiamond with Particle Size < 4 nm

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1285 ◽  
Author(s):  
Andrei Trofimuk ◽  
Diana Muravijova ◽  
Demid Kirilenko ◽  
Aleksandr Shvidchenko
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Synthetic Diamond ◽  
Average Particle Size ◽  
Average Particle ◽  
Detonation Nanodiamond ◽  
New Approach ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

Detonation nanodiamond is a commercially available synthetic diamond that is obtained from the carbon of explosives. It is known that the average particle size of detonation nanodiamond is 4–6 nm. However, it is possible to separate smaller particles. Here we suggest a new approach for the effective separation of detonation nanodiamond particles by centrifugation of a “hydrosol/glycerol” system. The method allows for the production of the detonation nanodiamond hydrosol with a very sharp distribution in size, where more than 85% of particles have a size ranging 1–4 nm. The result is supported by transmission electron microscopy, atomic force microscopy, and dynamic light scattering.

scholarly journals Synthesis of Pure Nano semiconductor Oxide ZnO with Different AgNO3 Concentrations

2017 ◽  
Vol 14 (2) ◽  
pp. 379-389
Author(s):  
Baghdad Science Journal
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Zinc Nitrate ◽  
Precipitation Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Agno3 Solution ◽  
Atomic Force ◽  
Scanning Electron

Zinc oxide nanoparticles sample is prepared by the precipitation method. This method involves using zinc nitrate and urea in aqueous solution, then (AgNO3) Solution with different concentrations is added. The obtained precipitated compound is structurally characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR). The average particle size of nanoparticles is around 28nm in pure, the average particle size reaches 26nm with adding AgNO3 (0.05g in100ml =0.002 M) (0.1g in100ml=0.0058M), AgNO3 (0.2g in 100ml=0.01M) was 25nm. The FTIR result shows the existence of -CO, -CO2, -OH, and -NO2- groups in sample and oxides (ZnO, Ag2O).and used an atomic force microscope and microscope scanning electron to model the record.

Preparation ZnO nanoparticles with Different Concentration by Laser Ablation in Liquid

2021 ◽  
Vol 39 (1B) ◽  
pp. 197-202
Author(s):  
Ghufran S. Jaber ◽  
Khawla S. Khashan ◽  
Maha J. Abbas
Keyword(s):  
Particle Size ◽  
Laser Ablation ◽  
Laser Pulse ◽  
Laser Energy ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Pulse Number ◽  
Average Particle ◽  
Zno Nps ◽  
Laser Ablation In Liquid

The effects of varying laser pulse numbers on the fabricated of ZnONPs by pulsed laser ablation in deionized water of Zn-metal are investigated. The Nd: YAG laser at energy 600mJ prepared three samples by change the laser pulse number (100, 150, and 200). The results were collected and examined using an electron scanning microscope, XRD – diffraction, and transmission electron microscope. The result revealed the colloidal spherical shape and the homogeneous composition of the ZnO NPs. The nanoparticles resulted in different concentrations and sized distributions by changing the pulse number of a laser. The average particle size and the mass concentration of particle size increase with an increasing number of laser pulses by fixed the laser energy.

scholarly journals Water-Dispersible Phytosterol Nanoparticles: Preparation, Characterization, and in vitro Digestion

2022 ◽  
Vol 8 ◽  
Author(s):  
Ao Li ◽  
Aixia Zhu ◽  
Di Kong ◽  
Chunwei Wang ◽  
Shiping Liu ◽  
...  
Keyword(s):  
Particle Size ◽  
Soybean Lecithin ◽  
Average Particle Size ◽  
Soy Protein Isolate ◽  
In Vitro Digestion ◽  
Bimodal Distribution ◽  
Average Particle ◽  
Food Ingredients ◽  
The Impact

For improving solubility and bioaccessibility of phytosterols (PS), phytosterol nanoparticles (PNPs) were prepared by emulsification–evaporation combined high-pressure homogenization method. The organic phase was formed with the dissolved PS and soybean lecithin (SL) in anhydrous ethanol, then mixed with soy protein isolate (SPI) solution, and homogenized into nanoparticles, followed by the evaporation of ethanol. The optimum fabrication conditions were determined as PS (1%, w/v): SL of 1:4, SPI content of 0.75% (w/v), and ethanol volume of 16 ml. PNPs were characterized to have average particle size 93.35 nm, polydispersity index (PDI) 0.179, zeta potential −29.3 mV, and encapsulation efficiency (EE) 97.3%. The impact of temperature, pH, and ionic strength on the stability of fabricated PNPs was determined. After 3-h in vitro digestion, the bioaccessibility of PS in nanoparticles reached 70.8%, significantly higher than the 18.2% of raw PS. Upon freeze-drying, the particle size of PNPs increased to 199.1 nm, resulting in a bimodal distribution. The solubility of PS in water could reach up to 2.122 mg/ml, ~155 times higher than that of raw PS. Therefore, this study contributes to the development of functional PS-food ingredients.

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 Modeling of Miniemulsion Polymerization of Styrene with Macro-RAFT Agents to Theoretically Compare Slow Fragmentation, Ideal Exchange and Cross-Termination Cases

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 320 ◽  
Author(s):  
Dries Devlaminck ◽  
Paul Van Steenberge ◽  
Marie-Françoise Reyniers ◽  
Dagmar D’hooge
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Miniemulsion Polymerization ◽  
Monomer Conversion ◽  
Water Soluble ◽  
Explicit Calculation ◽  
Average Particle ◽  
Intermediate Radical ◽  
Raft Agent ◽  
The Impact

A 5-dimensional Smith-Ewart based model is developed to understand differences for reversible addition-fragmentation chain transfer (RAFT) miniemulsion polymerization with theoretical agents mimicking cases of slow fragmentation, cross-termination, and ideal exchange while accounting for chain length and monomer conversion dependencies due to diffusional limitations. The focus is on styrene as a monomer, a water soluble initiator, and a macro-RAFT agent to avoid exit/entry of the RAFT leaving group radical. It is shown that with a too low RAFT fragmentation rate coefficient it is generally not afforded to consider zero-one kinetics (for the related intermediate radical type) and that with significant RAFT cross-termination the dead polymer product is dominantly originating from the RAFT intermediate radical. To allow the identification of the nature of the RAFT retardation it is recommended to experimentally investigate in the future the impact of the average particle size (dp) on both the monomer conversion profile and the average polymer properties for a sufficiently broad dp range, ideally including the bulk limit. With decreasing particle size both a slow RAFT fragmentation and a fast RAFT cross-termination result in a stronger segregation and thus rate acceleration. The particle size dependency is different, allowing further differentiation based on the variation of the dispersity and end-group functionality. Significant RAFT cross-termination is specifically associated with a strong dispersity increase at higher average particle sizes. Only with an ideal exchange it is afforded in the modeling to avoid the explicit calculation of the RAFT intermediate concentration evolution.

Preparation and Particle Size Characterization of Cu Nanoparticles Prepared by Anodic Arc Plasma

2010 ◽  
Vol 92 ◽  
pp. 163-169
Author(s):  
Hong Xia Qiao ◽  
Zhi Qiang Wei ◽  
Ming Ru Zhou ◽  
Zhong Mao He
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Specific Surface ◽  
Size Distribution ◽  
Surface Area ◽  
Specific Surface Area ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Average Particle ◽  
Uniform Size

Copper nanoparticles were successfully prepared in large scales by means of anodic arc discharging plasma method in inert atmosphere. The particle size, specific surface area, crystal structure and morphology of the samples were characterized by X-ray diffraction (XRD), BET equation, transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED). The experiment results indicate that the crystal structure of the samples is fcc structure as same as that of the bulk materials. The specific surface area is is 11 m2/g, with the particle size distribution ranging from 30 to 90 nm, the average particle size about 67nm obtained from TEM and confirmed from XRD and BET results. The nanoparticles have uniform size, higher purity, narrow size distribution and spherical shape can be prepared by this convenient and effective method.

Characteristics of La0.8Sr0.05Ca0.15CrO3 Interconnect Material for SOFC Synthesized by a Modified Pechini Method, USP, and GNP

2007 ◽  
Vol 124-126 ◽  
pp. 799-802
Author(s):  
Tak Hyoung Lim ◽  
Gil Yong Lee ◽  
Dong Hyun Peck ◽  
Rak Hyun Song ◽  
Dong Ryul Shin
Keyword(s):  
Particle Size ◽  
Perovskite Phase ◽  
Pechini Method ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Average Particle ◽  
Orthorhombic Structure ◽  
Single Perovskite Phase ◽  
Modified Pechini Method ◽  
Interconnect Material

The characteristics of La0.8Sr0.05Ca0.15CrO3 interconnect material synthesized by modified pechini method, USP, and GNP was investigated. The powder synthesized by Pechini method exhibited somewhat aggregated shape. The precursor synthesized by USP had spherical shape and their particle size decreased somewhat after calcining procedure at 1000oC. In the case of GNP, the precursor formed agglomerated particles. The average particle size of powders synthesized by Pechini method, USP, and GNP were 0.4+m, 0.6+m, and below 10nm, respectively. The La0.8Sr0.05Ca0.15CrO3 powder had a single perovskite phase and orthorhombic structure. After sintering at 1400oC and 1500oC, the relative density of samples synthesized by pechini method was approximately 95% and that of samples synthesized by USP was slightly small. However, that of the samples synthesized by GNP was approximately 92%.

Mechanical Properties of AA 5754 Hybrid Metal Matrix Composite Fabricated through Rheo-Squeeze Casting

2020 ◽  
Vol 979 ◽  
pp. 10-15
Author(s):  
K. Sekar ◽  
K. Jayakumar
Keyword(s):  
Particle Size ◽  
Tensile Strength ◽  
Metal Matrix ◽  
Squeeze Casting ◽  
Base Alloy ◽  
Average Particle Size ◽  
Casting Process ◽  
Matrix Alloy ◽  
Average Particle ◽  
The Impact

Hybrid metal matrix composites (MMCs) were prepared with AA 5754 as matrix and B4C (fixed with 1 wt.% and average particle size as 25 μm) and Al2O3 reinforcements (varied from 0.5 to 2 wt. % with the interval of 0.5 and average particle size as 50 nm) using Rheo-squeeze casting process. Microstructure images were taken to observe the uniform distribution of reinforcement particles on the matrix alloy. The tensile strength for AA 5754 with 1 wt.% B4C and 2 wt.% Al2O3 hybrid composite showed higher value compared to base alloy and other composites. The wt. % of Al2O3 in the composite is increased to 2 %, the tensile strength and compressive strength were also increased due to combined Rheo-squeeze casting. AA 5754 reinforced with 1 wt.% B4C and 1.5 wt.% Al2O3 MMC indicated the Impact strength value of 30 Joules which is higher than AA 5754 matrix alloy and other compositions.

Mechanical retention – Influence of filler floc size and grammage of the fibre web

2012 ◽  
Vol 27 (2) ◽  
pp. 202-207 ◽  
Author(s):  
Karin Athley ◽  
Lars Granlöf ◽  
Daniel Söderberg ◽  
Mikael Ankerfors ◽  
Göran Ström
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Pilot Trial ◽  
Average Particle ◽  
Paper Machine ◽  
Quartz Particle ◽  
Drainage Time ◽  
Fibre Layer ◽  
Filler Retention ◽  
The Impact

Abstract An investigation of the impact of particle size on the mechanical retention of particles in a fibre network has been conducted. The particles used were five sets of quartz particle fractions having fairly narrow particle size distributions with average particle size ranging from a few μm to around 100 μm. The particles were used to model flocculated filler aggregates as part of a larger study of the effect of pre-flocculation on mechanical retention. Pre-flocculation of the filler is a possible strategy to increase the filler content of paper without deterioration of strength properties. A modified laboratory hand sheet former, known as the Rapid Drainage Device (RDD) was used. The major modification consisted of a long pipe that acted as a suction leg, which provides a dewatering vacuum at the same level as on a paper machine. The experimental results showed that mechanical filler retention increased linearly with particle size and grammage of the fibre layer above a critical grammage which depended on particle size. The linear relation was also seen in a pilot scale trial on the FEX pilot-paper machine at Innventia. During this trial fine paper was produced using pre-flocculated filler where the mean particle size of the flocs and fibres was measured in the flow to the headbox. The results from this pilot trial show that mechanical retention is an important part of the total filler retention. Drainage time and therefore drainage resistance increased with the grammage of the fibre layer and amount of quartz particle added. Drainage time, compared at total grammage (i.e. the sum of fibre and quartz particle grammage) was lowest for a fraction of medium-sized particles, with a median size of 35 mm. There was no obvious effect on retention or drainage resistance of a change in the dewatering pressure from 27.5 to 41.5 kPa.

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