Particle-size distribution of inorganic water soluble ions in the venezuelan savannah atmosphere during burning and nonburning periods

1988 ◽  
Vol 7 (4) ◽  
pp. 369-388 ◽  
Author(s):  
Eugenio Sanhueza ◽  
Alberto Rond�n
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Water Soluble ◽  
Soluble Ions ◽  
Water Soluble Ions ◽  
Venezuelan Savannah

scholarly journals Characteristics of Aerosol during a Severe Haze-Fog Episode in the Yangtze River Delta: Particle Size Distribution, Chemical Composition, and Optical Properties

Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 56 ◽  
Author(s):  
Ankang Liu ◽  
Honglei Wang ◽  
Yi Cui ◽  
Lijuan Shen ◽  
Yan Yin ◽  
...  
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Chemical Composition ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Water Soluble ◽  
Air Masses ◽  
Soluble Ions ◽  
Wide Range ◽  
Water Soluble Ions

Particle size distribution, water soluble ions, and black carbon (BC) concentration in a long-term haze-fog episode were measured using a wide-range particle spectrometer (WPS), a monitor for aerosols and gases (MARGA), and an aethalometer (AE33) in Nanjing from 16 to 27 November, 2018. The observation included five processes of clean, mist, mix, haze, and fog. Combined with meteorological elements, the HYSPLIT model, and the IMPROVE model, we analyzed the particle size distribution, chemical composition, and optical properties of aerosols in different processes. The particle number size distribution (PNSD) in five processes differed: It was bimodal in mist and fog and unimodal in clean, mix, and haze. The particle surface area size distribution (PSSD) in different processes showed a bimodal distribution, and the second peak of the mix and fog processes shifted to a larger particle size at 480 nm. The dominant air masses in five processes differed and primarily originated in the northeast direction in the clean process and the southeast direction in the haze process. In the mist, mix, and fog processes local air masses dominated. NO3− was the primary component of water soluble ions, with the lowest proportion of 45.6% in the clean process and the highest proportion of 53.0% in the mix process. The ratio of NH4+ in the different processes was stable at approximately 23%. The ratio of SO42− in the clean process was 26.2%, and the ratio of other processes was approximately 20%. The average concentration of BC in the fog processes was 10,119 ng·m−3, which was 3.55, 1.80, 1.60, and 1.46 times that in the processes of clean, mist, mix, and haze, respectively. In the different processes, BC was primarily based on liquid fuel combustion. NO3−, SO42−, and BC were the main contributors to the atmospheric extinction coefficient and contributed more than 90% in different processes. NO3− contributed 398.43 Mm−1 in the mix process, and SO42− and BC contributed 167.90 Mm−1 and 101.19 Mm−1, respectively, during the fog process.

scholarly journals Insight into winter haze formation mechanisms based on aerosol hygroscopicity and effective density measurements

2017 ◽  
Author(s):  
Yuanyuan Xie ◽  
Xingnan Ye ◽  
Zhen Ma ◽  
Ye Tao ◽  
Ruyu Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Particle Growth ◽  
Water Soluble ◽  
Effective Density ◽  
Pollution Level ◽  
Formation Mechanisms ◽  
Haze Pollution ◽  
Haze Formation

Abstract. We characterize a representative haze event from a series of periodic particulate matter (PM) episodes that occurred in Shanghai during winter 2014. Particle size distribution, hygroscopicity, and effective density were measured online, along with analysis of water-soluble inorganic ions and single particle mass spectrometry. Regardless of pollution level, the mass ratio of SNA/PM1.0 (sulfate, nitrate, and ammonium) slightly fluctuated around 0.28 over the whole observation, suggesting that both secondary inorganic compounds and carbonaceous aerosols (including soot and organic matter) contributed substantially to the haze formation. Nitrate was the most abundant ionic species during hazy periods, indicating that NOx contributed more to haze formation in Shanghai than did SO2. The calculated PM concentration from particle size distribution displayed a variation pattern similar to that of measured PM1.0 during the representative PM episode, indicating that enhanced pollution level was attributable to the elevated number of larger particles. The number fraction of the near-hydrophobic group increased as the PM episode developed, indicating accumulation of local emissions. Three "banana-shape" particle evolutions were consistent with the rapid increase in PM1.0 mass loading, indicating rapid size growth by condensation of condensable materials was responsible for the severe haze formation. Both hygroscopicity and effective density of the particles increased considerably with growing particle size during the banana-shaped evolutions, indicating that secondary transformation of NOx and SO2 was a major contributor to the particle growth. Our results suggest that the accumulation of gas-phase and particulate pollutants under stagnant meteorological conditions and subsequent rapid particle growth by secondary processes, were primarily responsible for the haze pollution in Shanghai during wintertime.

scholarly journals Docetaxel-loaded Poly(3HB-co-4HB) Biodegradable Nanoparticles: Impact of Co-polymer Composition

2020 ◽  
Author(s):  
Faisalina Ahmad Fisol ◽  
Fabio Sonvico ◽  
Paolo Colombo ◽  
Amirul Al-Ashraf Abdullah ◽  
Habibah A. Wahab ◽  
...  
Keyword(s):  
Particle Size ◽  
Drug Release ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Water Soluble ◽  
Polymer Composition ◽  
Narrow Particle Size Distribution ◽  
Wide Range ◽  
Polymer Ratio

Polyhydroxyalkanoate (PHA) co-polymers show relatively higher in vivo degradation rate compared to other PHAs thus they received 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), co-polymers biosynthesised from Cupriavidus sp. USMAA1020 isolated from Malaysian environment. Three co-polymers 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. Pre-formulation 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 term of average particles sizes around 150 nm and narrow particle size distribution (PDI below 0.100). The encapsulation efficiencies 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 nanoparticles 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.

scholarly journals Impact of Resistant Maltodextrin Addition on the Physico-Chemical Properties in Pasteurised Orange Juice

Foods ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1832
Author(s):  
Elías Arilla ◽  
Marta Igual ◽  
Javier Martínez-Monzó ◽  
Pilar Codoñer-Franch ◽  
Purificación García-Segovia
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Orange Juice ◽  
Chemical Properties ◽  
Water Soluble ◽  
Soluble Solids ◽  
Soluble Fibre ◽  
Physico Chemical ◽  
Resistant Maltodextrin

Resistant maltodextrin (RMD) is a water-soluble fibre that can be fermented in the colon and exert prebiotic effects. Therefore, its addition to food and beverage products could be beneficial from both technological and nutritional viewpoints. However, to date, most studies have focused on the stability of the prebiotic fibre rather than its impact in the original food matrices. Therefore, this work aimed to evaluate the addition of RMD on the physico-chemical properties of pasteurised orange juice (with and without pulp). °Brix, pH, acidity, particle size distribution, density, turbidity, rheology, and colour were measured in orange juices with increasing RMD concentrations (2.5, 5, and 7.5%). Control samples without RMD were also prepared. RMD added soluble solids to the orange juice, affecting the °Brix, density, turbidity, and rheology. Slight colour differences were observed, and lower citric acid content was achieved because of orange juice replacement with RMD. Differences in particle size distribution were exclusively because of pulp content. Further studies are needed to elucidate if potential consumers will appreciate such physico-chemical changes in organoleptic terms.

scholarly journals Preparation of 3D Printable HAp-based Composite Powder for Binder Jetting Process

2020 ◽  
Author(s):  
Fahimeh Dini ◽  
Seyed Amir Ghaffari ◽  
Jafar Javadpour ◽  
Hamid Reza Rezaie
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Chitosan Solution ◽  
Carboxymethyl Chitosan ◽  
Water Soluble ◽  
Print Quality ◽  
Water Soluble Polymers ◽  
Printing Quality ◽  
Binder Jetting

Abstract The purpose of this study was to prepare a 3D printable powder composed of hydroxyapatite and biocompatible polymers such as chitosan, dextrin, and polyvinylpyrrolidone for the binder jetting process. The relationship between powder properties such as flowability and particle size distribution, as well as printing quality were investigated in the binder jetting process. For this purpose, 3D printable powder and an appropriate solvent were designed and demonstrated by hydroxyapatite and water-soluble polymers such as carboxymethyl chitosan, dextrin, and PVP. Results showed that a combination of 60%wt. hydroxyapatite, 28%wt. carboxymethyl chitosan, 10% wt. dextrin, and 2% wt. PVP, with controlled particle size distribution according to the Dinger-Funk equation led to the best print quality. Finally, flash dipping of the 3D printed parts in chitosan solution resulted in increases of compressive and Young's modulus from 1.3 and 10 MPa to 7.4 and 125 MPa, respectively.

Hevea Latex of Large Particle Size

1940 ◽  
Vol 13 (2) ◽  
pp. 415-421
Author(s):  
J. McGavack
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Aqueous Ammonia ◽  
Water Soluble ◽  
Distribution Data ◽  
Particle Sizes ◽  
Volume Changes ◽  
Large Particle Size ◽  
Complete Work

Abstract The purpose of this paper is to report, primarily, the particle size distribution of modified Hevea latices. In addition, the purpose is to show that the amount of nitrogen absorbed by the rubber particles in a latex thoroughly washed by aqueous ammonia depends on the surface exposed. Until the careful and complete work of Lucas (Ind. Eng. Chem. 30, 146 (1938)), there were no reliable particle size distribution data on a normal latex by which the distribution curves of modified latices could be compared. Now, as a result of his excellent technique for measuring all of the particles, even the very small ones, we are able to discuss clearly surface and volume changes when these smaller sized particles are removed. This work was so conducted as to eliminate particle sizes which could not be photographed with microscopical equipment in visible light. It was eventually carried out in such a way as to remove all water-soluble materials not adsorbed on or dissolved in the latex particles which were to be subsequently analyzed for nitrogen.

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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