Plasma imaging for physical variations in laser-induced aerosol plasma with particle size increase

2020 ◽  
Vol 35 (11) ◽  
pp. 2649-2655
Author(s):  
Muhammad Sher Afgan ◽  
Sahar Sheta ◽  
Yuzhou Song ◽  
Weilun Gu ◽  
Zhe Wang
Keyword(s):  
Particle Size ◽  
Analytical Signal ◽  
Size Increase ◽  
Laser Induced Plasma ◽  
Signal Variation ◽  
Particle Size Increase ◽  
Plasma Imaging

Increased analytical signal variation with particle size is a result of physical variations in laser-induced plasma of aerosols.

A kinetic free mathematical model for the prediction of the K St reduction with the particle size increase

2018 ◽  
Vol 52 ◽  
pp. 93-98 ◽  
Author(s):  
Anna Fumagalli ◽  
Marco Derudi ◽  
Renato Rota ◽  
Jef Snoeys ◽  
Sabrina Copelli
Keyword(s):  
Mathematical Model ◽  
Particle Size ◽  
Size Increase ◽  
Particle Size Increase

scholarly journals Micronization of Curcuma xanthorrhiza Extract with Addition of PVP Using Supercritical CO2 as Anti-solvent

2021 ◽  
Vol 333 ◽  
pp. 08002
Author(s):  
Rucita Ramadhana ◽  
Sarah Duta Lestari ◽  
Syahna Almadilla ◽  
Rizky Prasetya ◽  
Siti Machmudah ◽  
...  
Keyword(s):  
Particle Size ◽  
Supercritical Co2 ◽  
Ethanolic Extract ◽  
Operating Conditions ◽  
Supercritical Antisolvent ◽  
Particle Size Increase ◽  
Mean Diameter ◽  
Particle Size And Morphology ◽  
Curcuma Xanthorrhiza ◽  
Size And Morphology

Curcuma xanthorrhiza Roxb, known as Temulawak or Javanese ginger, is a plant species. Its rhizomes are used as a medicinal herb. It contains curcumin as an active compound and ethereal oils mainly consisted of sesquiterpenes. In this work, Curcuma xanthorrhiza Roxb ethanolic extract was micronized with an addition of PVP using supercritical antisolvent (SAS) method. The ethanolic extract was obtained from dried Curcuma xanthorrhiza Roxb using soxhletation. For the micronization, the extracted compound solvent was a mixture of acetone and ethanol (90:10 (v/v)), while the supercritical CO2 was used as an antisolvent. The effect of operating conditions on the particle size and morphology was evaluated. Through this method, spherical Curcuma xanthorrhiza/PVP particles with mean diameter ranging from 191 ± 70 nm to 178 ± 57 nm were successfully formed. The particle size not significantly decreased as the pressure increased from 8 12 MPa. The addition of PVP is very effective to reduce the particle size, increase the solubility, and enhance the bioavailability of Curcuma xanthorrhiza extract. This work has the potential to improve the use of Curcuma xanthorrhiza in pharmaceutical and nutraceutical applications.

Diastase Activity Retention and Physical Properties of Honey/Arabic Gum Mixtures After Spray Drying and Storage

2017 ◽  
Vol 13 (6) ◽  
Author(s):  
Katarzyna Samborska ◽  
Aleksandra Wasilewska ◽  
Ewa Gondek ◽  
Ewa Jakubczyk ◽  
Anna Kamińska-Dwórznicka
Keyword(s):  
Heat Treatment ◽  
Particle Size ◽  
Physical Properties ◽  
Water Content ◽  
Spray Drying ◽  
Angle Of Repose ◽  
Limit Values ◽  
Arabic Gum ◽  
Particle Size Increase ◽  
Size And Morphology

Abstract The effect of heat treatment (75 °C) and spray drying with the addition of Arabic gum (inlet/outlet air temperature 180/75 °C), on the diastase activity of multifloral honey (MH) and rape honey (RH) was investigated. The physical properties of the powders (particle size and morphology, water content and activity, bulk loose and tapped density, angle of repose, hygroscopicity) directly after drying and after 12 weeks of storage were studied. During heat treatment, diastase activity decreased gradually, to decline below limit values after 180 min. Diastase activity in the powders was lower than in fresh honeys, but it was concluded that temperature was not the only factor affecting this decrease. Powders were characterized by low water content and medium flowability, which was improved after storage due to particle size increase. Diastase activity in powders was stable during storage.

Optical Monitoring of Laser-Induced Plasma Derived from Graphite and Characterization of the Deposited Carbon Film

1994 ◽  
Vol 48 (8) ◽  
pp. 945-950 ◽  
Author(s):  
Yasuo Iida ◽  
Edward S. Yeung
Keyword(s):  
Thin Films ◽  
Particle Size ◽  
Laser Ablation ◽  
Power Density ◽  
Vibrational Temperature ◽  
Carbon Film ◽  
Helium Atmosphere ◽  
Laser Induced Plasma ◽  
Surrounding Atmosphere ◽  
Ionization Temperature

Mechanisms of the deposition of carbon thin films by the laser ablation of graphite were investigated by monitoring the plasma emission. Parameters such as electron density, ionization temperature, and vibrational temperature during plasma growth were evaluated as a function of the laser power density and the surrounding atmosphere. Also, Raman spectra of the deposited films were measured so that the particle size can be estimated from the intensity ratio of the Raman bands around 1360 and 1580 cm−1. The increase in power density caused an increase in ionization temperature and vibrational temperature of carbon species in the plasma but a decrease of particle size of the deposited thin films. The existence of 10 Torr of helium as a surrounding atmosphere caused drastic changes in the plasma parameters. The films deposited with helium atmosphere showed a low optical band gap, which indicates heat restructuring of ablated graphite particles in the hot plasma. The results can be explained with a simple model of laser ablation and the subsequent interaction of ablated particles with the laser-induced plasma.

scholarly journals Preparation and Characterization of Nimesulide Nanoparticles For Dissolution Improvement

2018 ◽  
pp. 46-60
Keyword(s):  
Particle Size ◽  
Dissolution Rate ◽  
Precipitation Method ◽  
Scanning Calorimetry ◽  
Decrease Particle Size ◽  
Antisolvent Precipitation ◽  
Particle Size Analyzer ◽  
Particle Size Increase ◽  
Freeze Dried ◽  
Inflammatory Drugs

Nimesulide is one of the types of non-steroidal anti-inflammatory drugs, widely used as analgesic and antipyretic. It is classified as class II drugs according to BCS guidance because of low solubility in water that leads to decrease in dissolution rate. So, the objective of this study was to decrease particle size, increase solubility and dissolution rate of nimesulide by preparation of nimesulide nanoparticles using solvent/antisolvent precipitation method by addition of organic solution of drug onto the solution of stabilizer. The size of nimesulide nanoparticles were studied and considered by particle size analyzer, drug content and loading efficiency. The freeze-dried nanoparticles were characterized by field emission electron microscope, X-Ray powder diffraction, differential scanning calorimetry and saturated solubility measurement. Tablet was manufactured by direct compression. The tablets were evaluated for drug release to measure the effect of nanoparticles on the dissolution improvement of drug.

scholarly journals Laser-induced plasma imaging for low-pressure detection

2018 ◽  
Vol 26 (12) ◽  
pp. 15962 ◽  
Author(s):  
H. Yuan ◽  
Igor B. Gornushkin ◽  
Ardian B. Gojani ◽  
X. H. Wang ◽  
M. Z. Rong
Keyword(s):  
Low Pressure ◽  
Laser Induced Plasma ◽  
Plasma Imaging

scholarly journals Dynamic Aggregation of Poly-N-Isopropylacrylamide Characterized Using Second-Order Scattering

2018 ◽  
Vol 72 (9) ◽  
pp. 1341-1348 ◽  
Author(s):  
Luke A. Fulton ◽  
Pei Zhang ◽  
W. Rudolf Seitz ◽  
John G. Tsavalas ◽  
Roy P. Planalp
Keyword(s):  
Particle Size ◽  
Light Scattering ◽  
Colloidal Stability ◽  
Second Order ◽  
Aggregation Process ◽  
Macromolecular Assembly ◽  
Particle Size Increase ◽  
Sample Composition ◽  
Monodisperse Polystyrene

A second-order scattering (SOS) method is presented for the characterization of aqueous particle suspensions undergoing aggregation. Scattering intensities are measured at 90° by a standard fluorimeter and referenced against dynamic light scattering (DLS) measurements to determine particle size increase in a metal-promoted aggregation process for 0.05 mg/mL aqueous poly-N-isopropylacrylamide (PNIPAm), MW ∼10 k g/mol. Particle size increases monotonically from 30 nm to 210 nm at temperature 308 K. A further validation of the SOS method was performed using monodisperse polystyrene reference particles sized at 52 nm, 101 nm, 151 nm, and 206 nm, which demonstrated the technique’s accuracy to within 6% and its versatility with respect to sample composition. The technique is ideal for monitoring colloidal stability and macromolecular assembly and it can be performed at lower concentrations than are typically used in DLS.

scholarly journals Optimization and Kinetic Modeling of the Removal of Lead from Enugu Coal by Acid Leaching

2019 ◽  
pp. 1-13
Author(s):  
Okoro Sylvanus Ezenwa ◽  
Asadu Christian Oluchukwu ◽  
Abuh Mark Agaba
Keyword(s):  
Particle Size ◽  
Dissolution Rate ◽  
Acid Concentration ◽  
Orthogonal Design ◽  
Acid Leaching ◽  
Kinetic Studies ◽  
Ion Concentration ◽  
Quadratic Model ◽  
Hydrogen Ion Concentration ◽  
Particle Size Increase

Removal of lead from Enugu coal with different acids as the leachant under different conditions such as leaching time, particle size, acid concentration, and leachant volume was investigated in this studies. The filtrate from each treatment was analyzed with Atomic Absorption X-ray Spectrometer (AAS) to determine the amount of lead leached. Nitric acid was found to be the best acid for the leaching of lead from Enugu coal. Kinetic studies carried out showed that the dissolution rate increased with: decreasing particle size, increase in stirring speed, acid concentration and leaching temperature. The experimental results revealed that the dissolution rate is a chemical reaction controlled via hydrogen ion concentration [H+], with reaction order of 0.9 and the reaction kinetics can be expressed as 1-(1-X)1/3 =2.566x10-4(CHNO3)0.86 (dp).992 (L/S).44 (SS).049 exp(53.49/RT). A quadratic model was predicted and optimized using second order orthogonal design (Box-Benken) which resulted in Particle size of 40µm, reaction time of 8.5 hours, and HNO3 concentration of 2mol/dm3. The optimum conditions were validated at model desirability of 1. Experimental value of 96.39% with error of 0.530% was removed.

scholarly journals ATOMIZATION CHARACTERISTICS OF FLAT FAN NOZZLES FOR PRECISION PESTICIDE APPLICATION AT LOW PRESSURES

2020 ◽  
Vol 61 (2) ◽  
pp. 293-304
Author(s):  
Shougen Li ◽  
Yaxiong Wang ◽  
Chongchong Chen ◽  
Feng Kang ◽  
Wenbin Li
Keyword(s):  
Particle Size ◽  
High Reliability ◽  
Theoretical Data ◽  
Droplet Velocity ◽  
Spray Angle ◽  
Equivalent Diameter ◽  
Pesticide Application ◽  
Particle Size Increase ◽  
Atomization Characteristics ◽  
Relative Errors

At present, the theory of precision pesticide application in agriculture and forestry has some shortcomings. Therefore, the Phase Doppler Interferometer (PDI) was used to establish the atomization model of three common brands (Lechler, Teejet and Feizhuo) flat fan nozzles in near fog field (0.3-0.5m) at low pressure (0.20-0.30mPa). The results show that the average absolute errors of droplet velocity of three brands of nozzles are 0.629, 0.521 and 0.684 m/s respectively, and the relative errors are 9.22, 9.60 and 11.89%, respectively. The average absolute errors of theoretical data of droplet size are 17.821, 13.801 and 22.140 μ m, and the relative errors are 8.40, 5.82 and 11.67%, respectively. The experimental theoretical model has high reliability. In addition, the results show that the droplet velocity and particle size increase with the increase of the equivalent diameter of the nozzle outlet. With the increase of spray angle, droplet velocity and particle size decrease gradually, and the rate of velocity decrease gradually. The research results are of great significance to further analyse the atomization characteristics of flat fan nozzle and guide the precise application of pesticide.

scholarly journals Hydrophobic Modification of Copper Nanospheres for Incorporation into Poloxamer Micelles, Aggregated Micellar Nanocages and Supramolecular Assemblies

2019 ◽  
Vol 9 (2) ◽  
pp. 108-127
Author(s):  
Yunlong Xu ◽  
Kaspars Melkis ◽  
Chinn T. Sia ◽  
Dipak K. Sarker
Keyword(s):  
Light Scattering ◽  
Ex Vivo ◽  
Nano Particles ◽  
Size Increase ◽  
Angle Measurements ◽  
Pluronic F108 ◽  
Particle Size Increase ◽  
Contact Angle Measurements ◽  
Metal Nano Particles

Background: Polymer nanogels are increasingly used for the encapsulation of nano-solids and quantum dots such as in advanced forms of drug and therapeutic isotope delivery. Objective: Unlike ex vivo application of systems in vivo application and internalization are likely to suffer from aspects of failure to ensure safety and biocompatibility. Biocompatible hydrophilic poloxamer (Pluronic F108 and F68) micelles were studied by light scattering and tensiometry. Methods: The micelles of nano-gels are synthetic heteropolymer aggregates, which are used to encapsulate drugs but in this study chemically-modified (hydrophobized) copper nano-spheres, for the purposes of demonstration for further application and medical use. Copper benzoate nano-particles (CuBzNPs) were produced by maceration and subsequently stabilized in Pluronic F108 solution was added at different concentrations. Results: The resulting particle size increase was studied by dynamic light scattering. Moderate size increase was observed at low Pluronic F108 concentrations, which indicated successful coating, but at higher F108 concentrations large size agglomerates formed. Coated copper benzoate nano-particles (CuBzNPs) were fabricated as a proof-of-principle and as a substitute for bare metal nano-particles (MNs), which were not successfully entrained in the poloxamer nano-gel. As part of the synthesis copper benzoate (CuBz) beads and their characterization through contact angle measurements were performed. Conclusion: Micelles sizes of 4 nm for F68 Pluronic at equilibrium surface tensions of 36 mNm-1 were captured in weak, 1.25 to 2.0 Pas pseudoplastic gels fabricated from hydroxypropylmethylcellulose (HPMC).

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