scholarly journals Influence of a Coaxial Electrospraying System on the n-Hexadecane/Polycaprolactone Phase Change Microcapsules Properties

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2205 ◽  
Author(s):  
Shengchang Zhang ◽  
Yuan Chen ◽  
Christine Campagne ◽  
Fabien Salaün
Keyword(s):  
Particle Size ◽  
Thermal Properties ◽  
Phase Change ◽  
Size Distribution ◽  
Encapsulation Efficiency ◽  
High Efficiency ◽  
Thermal Regulation ◽  
Coaxial Nozzle ◽  
Mean Diameter ◽  
Working Parameters

Electrospraying is considered to be a green, high-efficiency method for synthesizing phase change microcapsules (mPCMs) for possible applications in the fields of energy storage and thermal regulation. In this study, a coaxial nozzle was used to prepare n-hexadecane/polycaprolactone (PCL) microparticles. The objectives of this study were to investigate the influence of working parameters and solutions on morphology, particle size, thermal properties and encapsulation efficiency. Thus, three theoretical loading contents in n-hexadecane (30%, 50% and 70% w/w) and two concentrations of PCL (5 and 10% w/v) were used. The structures, morphologies and thermal properties of mPCMs were characterized by optical microscopy (OM), scanning electron microscopy (SEM), differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA). Spherical microcapsules with a mean diameter of 10–20 µm were prepared. The increased concentration of n-hexadecane and PCL resulted in a change in the particle size distribution from a poly-disperse to monodisperse size distribution and in a change in the surface state from porous to non-porous. In addition, higher encapsulation efficiency (96%) and loading content (67%) were achieved by the coaxial nozzle using the high core-shell ratio (70/30) and 10% w/v of PCL. The latent heat of the mPCMs reached about 134 J.g−1. In addition, it was also observed that the thermal stability was improved by using a coaxial system rather than a single nozzle.

Optimization and Characterization of Aqueous Micellar Formulations for Ocular Delivery of an Antifungal Drug, Posaconazole

2020 ◽  
Vol 26 (14) ◽  
pp. 1543-1555 ◽  
Author(s):  
Meltem E. Durgun ◽  
Emine Kahraman ◽  
Sevgi Güngör ◽  
Yıldız Özsoy
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Size Distribution ◽  
Encapsulation Efficiency ◽  
Fungal Infections ◽  
In Vitro Release ◽  
Pluronic F127 ◽  
Glycol Succinate ◽  
Vitro Release

Background: Topical therapy is preferred for the management of ocular fungal infections due to its superiorities which include overcoming potential systemic side effects risk of drugs, and targeting of drugs to the site of disease. However, the optimization of effective ocular formulations has always been a major challenge due to restrictions of ocular barriers and physiological conditions. Posaconazole, an antifungal and highly lipophilic agent with broad-spectrum, has been used topically as off-label in the treatment of ocular fungal infections due to its highly lipophilic character. Micellar carriers have the potential to improve the solubility of lipophilic drugs and, overcome ocular barriers. Objective: In the current study, it was aimed optimization of posaconazole loaded micellar formulations to improve aqueous solubility of posaconazole and to characterize the formulations and to investigate the physical stability of these formulations at room temperature (25°C, 60% RH), and accelerated stability (40°C, 75% RH) conditions. Method: Micelles were prepared using a thin-film hydration method. Pre-formulation studies were firstly performed to optimize polymer/surfactant type and to determine their concentration in the formulations. Then, particle size, size distribution, and zeta potential of the micellar formulations were measured by ZetaSizer Nano-ZS. The drug encapsulation efficiency of the micelles was quantified by HPLC. The morphology of the micelles was depicted by AFM. The stability of optimized micelles was evaluated in terms of particle size, size distribution, zeta potential, drug amount and pH for 180 days. In vitro release studies were performed using Franz diffusion cells. Results: Pre-formulation studies indicated that single D-ɑ-tocopheryl polyethylene glycol succinate (TPGS), a combination of it and Pluronic F127/Pluronic F68 are capable of formation of posaconazole loaded micelles at specific concentrations. Optimized micelles with high encapsulation efficiency were less than 20 nm, approximately neutral, stable, and in aspherical shape. Additionally, in vitro release data showed that the release of posaconazole from the micelles was higher than that of suspension. Conclusion: The results revealed that the optimized micellar formulation of posaconazole offers a potential approach for topical ocular administration.

Synthesis and Thermal Properties of Magnesium Sulfate Heptahydrate/Urea Resin as Thermal Energy Storage Micro-Encapsulated Phase Change Material

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Chenzhen Liu ◽  
Ling Ma ◽  
Zhonghao Rao ◽  
Yimin Li
Keyword(s):  
Particle Size ◽  
Thermal Properties ◽  
Phase Change ◽  
Magnesium Sulfate ◽  
Phase Change Material ◽  
Core Material ◽  
Scanning Calorimetry ◽  
Sulfate Heptahydrate ◽  
Encapsulated Phase Change Material ◽  
Change Material

In this study, micro-encapsulated phase change material (microPCM) was successfully synthesized by emulsion polymerization method, using magnesium sulfate heptahydrate (MSH) as core material and urea resin (UR) as shell material. The surface morphologies and particle size distributions of the microPCM were tested by scanning electron microscopy (SEM) and laser particle size analyzer. The chemical structure of microPCM was analyzed by Fourier-transform infrared spectroscopy (FTIR). The thermal properties were investigated by differential scanning calorimetry (DSC) and thermal conductivity coefficient instrument, respectively.

scholarly journals A New High-Efficiency Procedure for Aggregate Gradation Determination of the Railway Ballast by Means Image Recognition Method

2013 ◽  
Vol 59 (4) ◽  
pp. 469-482 ◽  
Author(s):  
M. Guerrieri ◽  
G. Parla
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
High Efficiency ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Railway Ballast ◽  
Aggregate Gradation ◽  
Railway Line ◽  
Near Future

Abstract The mechanical characteristics of the railway superstructure are related to the properties of the ballast, and especially to the particle size distribution of its grains. Under the constant stress-strain of carriages, the ballast can deteriorate over time, and consequently it should properly be monitored for safety reasons. The equipment which currently monitors the railway superstructure (like the Italian diagnostic train Archimede) do not make any “quantitative” evaluation of the ballast. The aim of this paper is therefore to propose a new methodology for extracting railway ballast particle size distribution by means of the image processing technique. The procedure has been tested on a regularly operating Italian railway line and the results have been compared with those obtained from laboratory experiments, thus assessing how effective is the methodology which could potentially be implemented also in diagnostic trains in the near future.

Phase Change Materials of Microcapsules Containing Paraffin

2012 ◽  
Vol 482-484 ◽  
pp. 1596-1599
Author(s):  
Dian Wu Huang ◽  
Hong Mei Wang
Keyword(s):  
Particle Size ◽  
Thermal Properties ◽  
Phase Change ◽  
Phase Change Materials ◽  
In Situ Polymerization ◽  
Core Material ◽  
Study Phase ◽  
Shell Material ◽  
Core Content

In this study, phase change microcapsules were prepared by in situ polymerization using paraffin as core material, poly(MMA -co- MAA) as shell material, Tween60/span60 as emulsifier. The surface morphology, thermal properties and particle size distribution of the prepared microcapsules were investigated by using SEM, TGA, DSC and ELS. The effects of paraffin core content and amount of emulsifier on the properties of microcapsules were studied.

scholarly journals Foster®: A High-Efficiency Combination Metered Dose Inhaler with Consistent Particle Size Distribution at Alternative Flow Rates

2014 ◽  
Vol 4 (1-2) ◽  
pp. 1-5 ◽  
Author(s):  
Roberta De Maria ◽  
Ingrid Zagnoni ◽  
Alessandro Bodria ◽  
Sauro Bonelli ◽  
Massimiliano Dagli Alberi ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
High Efficiency ◽  
Dose Inhaler ◽  
Metered Dose Inhaler ◽  
Flow Rates ◽  
Metered Dose

scholarly journals Particle size distributions from laboratory-scale biomass fires using fast response instruments

2010 ◽  
Vol 10 (16) ◽  
pp. 8065-8076 ◽  
Author(s):  
S. Hosseini ◽  
Q. Li ◽  
D. Cocker ◽  
D. Weise ◽  
A. Miller ◽  
...  
Keyword(s):  
United States ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Geometric Mean ◽  
The United States ◽  
Biomass Combustion ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Mean Diameter

Abstract. Particle size distribution from biomass combustion is an important parameter as it affects air quality, climate modelling and health effects. To date, particle size distributions reported from prior studies vary not only due to difference in fuels but also difference in experimental conditions. This study aims to report characteristics of particle size distributions in well controlled repeatable lab scale biomass fires for southwestern United States fuels with focus on chaparral. The combustion laboratory at the United States Department of Agriculture-Forest Service's Fire Science Laboratory (USDA-FSL), Missoula, MT provided a repeatable combustion and dilution environment ideal for measurements. For a variety of fuels tested the major mode of particle size distribution was in the range of 29 to 52 nm, which is attributable to dilution of the fresh smoke. Comparing mass size distribution from FMPS and APS measurement 51–68% of particle mass was attributable to the particles ranging from 0.5 to 10 μm for PM10. Geometric mean diameter rapidly increased during flaming and gradually decreased during mixed and smoldering phase combustion. Most fuels produced a unimodal distribution during flaming phase and strong biomodal distribution during smoldering phase. The mode of combustion (flaming, mixed and smoldering) could be better distinguished using the slopes in MCE (Modified Combustion Efficiency) vs. geometric mean diameter than only using MCE values.

scholarly journals Particle size distributions from laboratory-scale biomass fires using fast response instruments

2010 ◽  
Vol 10 (4) ◽  
pp. 8595-8621 ◽  
Author(s):  
S. Hosseini ◽  
L. Qi ◽  
D. Cocker ◽  
D. Weise ◽  
A. Miller ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Geometric Mean ◽  
Biomass Combustion ◽  
Climate Modelling ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Mean Diameter ◽  
Particle Sizer

Abstract. Particle size distribution from biomass combustion is an important parameter as it affects air quality, climate modelling and health effects. To date particle size distributions reported from prior studies vary not only due to difference in fuels but also difference in experimental conditions. This study aims to report characteristics of particle size distribution in a well controlled repeatable lab scale biomass fires for southwestern US fuels. The combustion facility at the USDA Forest Service's Fire Science Laboratory (FSL), Missoula, MT provided repeatable combustion and dilution environment ideal for particle size distribution study. For a variety of fuels tested the major mode of particle size distribution was in the range of 29 to 52 nm, which was attributable to dilution of the fresh smoke. Comparing volume size distribution from Fast Mobility Particle Sizer (FMPS) and Aerodynamic Particle Sizer (APS) measurements, ~30% of particle volume was attributable to the particles ranging from 0.5 to 10 μm for PM10. Geometric mean diameter rapidly increased during flaming and gradually decreased during mixed and smoldering phase combustion. Most of fuels gave unimodal distribution during flaming phase and strong biomodal distribution during smoldering phase. The mode of combustion (flaming, mixed and smoldering) could be better distinguished using slopes in Modified Combustion Efficiency (MCE) vs. geometric mean diameter from each mode of combustion than only using MCE values.

HEPA Filter Performance Under Adverse Conditions

2007 ◽  
Author(s):  
Michael Parsons ◽  
Kristina Hogancamp ◽  
Steven Alderman ◽  
Charles Waggoner
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
High Efficiency ◽  
Department Of Energy ◽  
Emission Rates ◽  
Filter Function ◽  
Filter Performance ◽  
The Media ◽  
Effect Of Particle Size

This study involved challenging nuclear grade high-efficiency particulate air (HEPA) filters under a variety of conditions that can arise in Department of Energy (DOE) applications such as: low or high RH, controlled and uncontrolled challenge, and filters with physically damaged media or seals (i.e., leaks). Reported findings correlate filter function as measured by traditional differential pressure techniques in comparison with simultaneous instrumental determination of up and down stream PM concentrations. Additionally, emission rates and failure signatures will be discussed for filters that have either failed or exceeded their usable lifetime. Significant findings from this effort include the use of thermocouples up and down stream of the filter housing to detect the presence of moisture. Also demonstrated in the moisture challenge series of tests is the effect of repeated wetting of the filter. This produces a phenomenon referred to as transient failure before the tensile strength of the media weakens to the point of physical failure. An evaluation of the effect of particle size distribution of the challenge aerosol on loading capacity of filters is also included. Results for soot and two size distributions of KCl are reported. Loading capacities for filters ranged from approximately 70 g of soot to nearly 900 g for the larger particle size distribution of KCl.

scholarly journals Docetaxel-Loaded Poly(3HB-co-4HB) Biodegradable Nanoparticles: Impact of Copolymer Composition

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2123 ◽  
Author(s):  
A.F. Faisalina ◽  
Fabio Sonvico ◽  
Paolo Colombo ◽  
A.A. Amirul ◽  
H.A. Wahab ◽  
...  
Keyword(s):  
Particle Size ◽  
Drug Release ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Encapsulation Efficiency ◽  
Water Soluble ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Wide Range ◽  
Polymer Ratio

Polyhydroxyalkanoate (PHA) copolymers show a relatively higher in vivo degradation rate compared to other PHAs, thus, they receive a great deal of attention for a wide range of medical applications. Nanoparticles (NPs) loaded with poorly water-soluble anticancer drug docetaxel (DCX) were produced using poly(3-hydroxybutyrate-co-4-hydroxybutyrate), P(3HB-co-4HB), copolymers biosynthesised from Cupriavidus malaysiensis USMAA1020 isolated from the Malaysian environment. Three copolymers with different molar proportions of 4-hydroxybutirate (4HB) were used: 16% (PHB16), 30% (PHB30) and 70% (PHB70) 4HB-containing P(3HB-co-4HB). Blank and DCX-loaded nanoparticles were then characterized for their size and size distribution, surface charge, encapsulation efficiency and drug release. Preformulation studies showed that an optimised formulation could be achieved through the emulsification/solvent evaporation method using PHB70 with the addition of 1.0% PVA, as stabilizer and 0.03% VitE-TPGS, as surfactant. DCX-loaded PHB70 nanoparticles (DCX-PHB70) gave the desired particle size distribution in terms of average particle size around 150 nm and narrow particle size distribution (polydispersity index (PDI) below 0.100). The encapsulation efficiency result showed that at 30% w/w drug-to-polymer ratio: DCX- PHB16 NPs were able to encapsulate up to 42% of DCX; DCX-PHB30 NPs encapsulated up to 46% of DCX and DCX-PHB70 NPs encapsulated up to 50% of DCX within the nanoparticle system. Approximately 60% of DCX was released from the DCX-PHB70 NPs within 7 days for 5%, 10% and 20% of drug-to-polymer ratio while for the 30% and 40% drug-to-polymer ratios, an almost complete drug release (98%) after 7 days of incubation was observed.

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