scholarly journals Empirical Modelling of Hydrodynamic Effects on Starch Nanoparticles Precipitation in a Spinning Disc Reactor

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2202 ◽  
Author(s):  
Sahr Sana ◽  
Vladimir Zivkovic ◽  
Kamelia Boodhoo
Keyword(s):  
Particle Size ◽  
Reynolds Number ◽  
Rotational Speed ◽  
Precipitation Process ◽  
Empirical Modelling ◽  
Operating Variables ◽  
Antisolvent Precipitation ◽  
Passive Mixing ◽  
The Difference ◽  
Spinning Disc

Empirical correlations have been developed to relate experimentally determined starch nanoparticle size obtained in a solvent–antisolvent precipitation process with key hydrodynamic parameters of a spinning disc reactor (SDR). Three different combinations of dimensionless groups including a conventional Reynolds number (Re), rotational Reynolds number (Reω) and Rossby number (Ro) have been applied in individual models for two disc surfaces (smooth and grooved) to represent operating variables affecting film flow such as liquid flowrate and disc rotational speed, whilst initial supersaturation (S) has been included to represent varying antisolvent concentrations. Model 1 featuring a combination of Re, Reω and S shows good agreement with the experimental data for both the grooved and smooth discs. For the grooved disc, Re has a greater impact on particle size, whereas Reω is more influential on the smooth disc surface, the difference likely being due to the passive mixing induced by the grooves irrespective of the magnitude of the disc speed. Supersaturation has little impact on particle size within the limited initial supersaturation range studied. Model 2 which characterises both flow rate and disc rotational speed through Ro alone and combined with Re was less accurate in predicting particle size due to several inherent limitations.

scholarly journals Production of starch nanoparticles through solvent-antisolvent precipitation in a spinning disc reactor

2019 ◽  
Vol 8 (1) ◽  
pp. 507-515 ◽  
Author(s):  
Sahr Sana ◽  
Kamelia Boodhoo ◽  
Vladimir Zivkovic
Keyword(s):  
Particle Size ◽  
Nano Particles ◽  
Solvent Ratio ◽  
Size Distributions ◽  
Thin Film Flow ◽  
Disc Surface ◽  
Antisolvent Precipitation ◽  
Starch Nanoparticles ◽  
Solvent Flow ◽  
Spinning Disc

Abstract The spinning disc reactor (SDR) uses surface rotation to produce thin film flow with improved mixing and reduced residence times in chemical processing applications. Solvent-antisolvent precipitation is one such process that can benefit from these properties. This study investigates the film hydrodynamics and precipitation of starch nanoparticles by contacting starch dissolved in sodium hydroxide with ethanol as the antisolvent. One objective of this study is to understand how interactions of the disc surface topography (grooved and smooth) with other parameters such as liquid flowrate, antisolvent to solvent flow ratio and disc speed impact the mixing and precipitation processes. Results indicate that an increase in flow rate and rotational speed leads to smaller nano-particles and narrower size distributions, which is attributed to increased shear and instabilities within the liquid film. It was also observed that an increased antisolvent to solvent ratio caused a reduction in particle size, as increased antisolvent generated higher supersaturation. Results showed that although particle size was not significantly influenced by the disc texture, the size distribution was narrower and higher yields were obtained with the grooved disc surface. The grooved disc therefore offers the opportunity for higher throughput in the solvent-antisolvent precipitation of starch particles with better product quality.

scholarly journals Synthesis of Curcumin Nanoparticle from Curcuma xanthorrhiza Roxb Extract by Solvent-Antisolvent Precipitation Method

2019 ◽  
Vol 13 (2) ◽  
pp. 145
Author(s):  
Nur Rofiqoh Eviana Putri ◽  
Annisa Amalia Ulfah ◽  
Yuni Kusumastuti
Keyword(s):  
Particle Size ◽  
Water Solubility ◽  
Biomedical Application ◽  
Particle Size Analysis ◽  
Precipitation Method ◽  
Size Analysis ◽  
Precipitation Process ◽  
Yellow Colour ◽  
Antisolvent Precipitation ◽  
Curcuma Xanthorrhiza

A B S T R A C TCurcumin is an active compound found in temulawak (Curcuma xanthorrhiza Roxb.) extract which is widely used for biomedical application. However, the utilization of curcumin is still limited due to its properties i.e. hydrophobicity, poor stability, and low water solubility. Modification of curcumin molecule and process optimization during the extraction and purification process is needed to minimize the aforementioned limitations. One of the approaches is producing curcumin in nano size. This present research aims to optimize the synthesis of curcumin nanoparticle from Curcuma xanthorrhiza Roxb. extract using solvent-antisolvent precipitation method. Curcumin colour stability was also enhanced by controlling the pH during raw materials preparation. The obtained curcumin nanoparticle was then characterized using particle size analysis (PSA). Result showed that Curcuma xanthorrhiza Roxb. extract colour could be controlled by maintaining acidic environment. At the pH of 3, yellow colour of extract was obtained, meanwhile at neutral pH, the colour of extract changed into dark brown. PSA result showed that optimum stirring condition of precipitation process was obtained using 500 rpm stirring rate for 45 minutes which resulted in curcumin nanoparticle in the size range of 164.37±3.29 nm. Thus, by controlling the pH of extract at 3 during extraction process and using optimum stirring condition at 500 rpm for 45 minutes during precipitation process, more stable and soluble curcumin was successfully produced. A B S T R A KKurkumin merupakan salah satu senyawa aktif yang terkandung dalam ekstrak temulawak (Curcuma xanthorrhiza Roxb.) yang banyak digunakan untuk aplikasi biomedis. Meskipun demikian, pemanfaatan kurkumin masih terbatas dikarenakan sifatnya yang hidrofobik, stabilitas yang rendah, serta kelarutan di air yang rendah. Modifikasi kurkumin serta optimisasi proses ekstraksi maupun purifikasi perlu dilakukan untuk mengatasi kelemahan tersebut. Salah satu pendekatan yang dapat dilakukan adalah dengan membuat kurkumin dalam ukuran nano. Penelitian ini bertujuan untuk mengoptimasi pembuatan nanopartikel kurkumin dari ekstrak Curcuma xanthorrhiza Roxb. menggunakan metode presipitasi solven-antisolven. Stabilitas warna kurkumin dijaga dengan mengontrol pH saat persiapan bahan baku. Hasil nanopartikel kurkumin yang didapat kemudian dianalisis menggunakan particle size analysis (PSA). Hasil menunjukkan bahwa warna ekstrak Curcuma xanthorrhiza Roxb. dapat dijaga pada kondisi asam. Pada pH 3, ekstrak berwarna kuning cerah sedangkan pada pH netral, warna ekstrak berubah menjadi coklat gelap. Hasil PSA menunjukkan bahwa kondisi pengadukan yang optimum pada saat proses presipitasi diperoleh menggunakan kecepatan pengadukan 500 rpm selama 45 menit yang menghasilkan nanopartikel kurkumin dengan ukuran 164,37±3,29 nm. Dengan mengontrol ekstrak pada pH 3 selama proses ekstraksi dan menggunakan kondisi pengadukan optimum pada 500 rpm selama 45 menit pada proses presipitasi, kurkumin dengan stabilitas dan kelarutan yang baik dapat diperoleh. 

Processing of granite quarry solid waste into industrial high silica materials using leaching process with HCl concentration variation

2020 ◽  
Vol 11 (2) ◽  
pp. 43-50
Author(s):  
Yusup Hendronursito ◽  
Muhammad Amin ◽  
Slamet Sumardi ◽  
Roniyus Marjunus ◽  
Frista Clarasati ◽  
...  
Keyword(s):  
Particle Size ◽  
Rotational Speed ◽  
Inductively Coupled Plasma ◽  
Chemical Elements ◽  
Silica Content ◽  
X Ray ◽  
Concentration Variation ◽  
Leaching Process ◽  
Hcl Concentration ◽  
Granite Powder

This study was aimed to increase granite's silica content using the leaching process with HCl concentration variation. The granite used in this study came from Lematang, South Lampung. This study aims to determine the effect of variations in HCl concentration, particle size, and rotational speed on the crystalline phase and chemical elements formed in the silica product produced from granite. The HCl concentration variations were 6.0 M, 7.2 M, 8.4 M, and 9.6 M, the variation in particle size used was 270 and 400 mesh. Variations in rotational speed during leaching were 500 and 750 rpm. Granite powder was calcined at 1000 ºC for 2 hours. Characterization was performed using X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), and Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP- OES). The results showed that the silica content increased with increasing HCl concentration, the finer the particle size, and the higher the rotational speed. XRF analysis showed that the silica with the highest purity was leached with 9.6 HCl with a particle size of 400 mesh and a rotational speed of of 750 rpm, which was 73.49%. Based on the results above, by leaching using HCl, the Si content can increase from before. The XRD diffractogram showed that the granite powder formed the Quartz phase.

scholarly journals Investigating the Feasibility of Mefenamic Acid Nanosuspension for Pediatric Delivery: Preparation, Characterization, and Role of Excipients

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 574
Author(s):  
Nikhat Perween ◽  
Sultan Alshehri ◽  
T. S. Easwari ◽  
Vivek Verma ◽  
Md. Faiyazuddin ◽  
...  
Keyword(s):  
Particle Size ◽  
Mefenamic Acid ◽  
Hydroxypropyl Methylcellulose ◽  
Sodium Dodecyl ◽  
Aqueous Solubility ◽  
Oral Route ◽  
Precipitation Method ◽  
Antisolvent Precipitation

Molecules with poor aqueous solubility are difficult to formulate using conventional approaches and are associated with many formulation delivery issues. To overcome these obstacles, nanosuspension technology can be one of the promising approaches. Hence, in this study, the feasibility of mefenamic acid (MA) oral nanosuspension was investigated for pediatric delivery by studying the role of excipients and optimizing the techniques. Nanosuspensions of MA were prepared by adopting an antisolvent precipitation method, followed by ultrasonication with varying concentrations of polymers, surfactants, and microfluidics. The prepared nanosuspensions were evaluated for particle size, morphology, and rheological measures. Hydroxypropyl methylcellulose (HPMC) with varying concentrations and different stabilizers including Tween® 80 and sodium dodecyl sulfate (SLS) were used to restrain the particle size growth of the developed nanosuspension. The optimized nanosuspension formula was stable for more than 3 weeks and showed a reduced particle size of 510 nm with a polydispersity index of 0.329. It was observed that the type and ratio of polymer stabilizers were responsive on the particle contour and dimension and stability. We have developed a biologically compatible oral nanoformulation for a first-in-class drug beautifully designed for pediatric delivery that will be progressed toward further in vivo enabling studies. Finally, the nanosuspension could be considered a promising carrier for pediatric delivery of MA through the oral route with enhanced biological impact.

Effect of particle size and delignification on the rate of digestion of hemicellulose and cellulose by cellulase in mature pangola grass stems

1983 ◽  
Vol 34 (3) ◽  
pp. 241 ◽  
Author(s):  
CW Ford
Keyword(s):  
Particle Size ◽  
Cell Walls ◽  
Trichoderma Viride ◽  
Structural Features ◽  
Cell Wall Polysaccharides ◽  
Particle Size Reduction ◽  
Digitaria Decumbens ◽  
Hemicellulose Degradation ◽  
Before And After ◽  
The Difference

Stem cell walls of pangola grass (Digitaria decumbens) were ground to two particle sizes (c. 1 and 0.1 mm diameter), and incubated with cellulase (ex. Trichoderma viride) for varying times before and after delignification. Total cell walls finely ground (0.1 mm) with a Spex Shatterbox mill were initially degraded more rapidly (to 24 h) than delignified 1 mm particles. Thereafter the delignified material was solubilized to a greater extent. Subsequent specific determinations of cell wall polysaccharides indicated that delignification increased the rate of hemicellulose degradation to a greater extent than did particle size reduction, whereas the opposite was found for cellulose. The difference between delignified and Spex-ground residues, in terms of the amount of polysaccharide digested, was much greater for cellulose than hemicellulose. It is concluded that structural features play a more important role in limiting cellulase degradation of cellulose than does association with lignin, the reverse being so for hemicellulose.

scholarly journals Enhanced Water Solubility and Oral Bioavailability of Paclitaxel Crystal Powders through an Innovative Antisolvent Precipitation Process: Antisolvent Crystallization Using Ionic Liquids as Solvent

Pharmaceutics ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1008 ◽  
Author(s):  
Qilei Yang ◽  
Chang Zu ◽  
Wengang Li ◽  
Weiwei Wu ◽  
Yunlong Ge ◽  
...  
Keyword(s):  
Oral Bioavailability ◽  
High Performance ◽  
Water Solubility ◽  
Water Soluble ◽  
Precipitation Process ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Antisolvent Precipitation ◽  
Antisolvent Crystallization ◽  
Artificial Gastric Juice

Paclitaxel (PTX) is a poor water-soluble antineoplastic drug with significant antitumor activity. However, its low bioavailability is a major obstacle for its biomedical applications. Thus, this experiment is designed to prepare PTX crystal powders through an antisolvent precipitation process using 1-hexyl-3-methylimidazolium bromide (HMImBr) as solvent and water as an antisolvent. The factors influencing saturation solubility of PTX crystal powders in water in water were optimized using a single-factor design. The optimum conditions for the antisolvent precipitation process were as follows: 50 mg/mL concentration of the PTX solution, 25 °C temperature, and 1:7 solvent-to-antisolvent ratio. The PTX crystal powders were characterized via scanning electron microscopy, Fourier transform infrared spectroscopy, high-performance liquid chromatography–mass spectrometry, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Raman spectroscopy, solid-state nuclear magnetic resonance, and dissolution and oral bioavailability studies. Results showed that the chemical structure of PTX crystal powders were unchanged; however, precipitation of the crystalline structure changed. The dissolution test showed that the dissolution rate and solubility of PTX crystal powders were nearly 3.21-folds higher compared to raw PTX in water, and 1.27 times higher in artificial gastric juice. Meanwhile, the bioavailability of PTX crystal increased 10.88 times than raw PTX. These results suggested that PTX crystal powders might have potential value to become a new oral PTX formulation with high bioavailability.

Altitude Effects on the Performance of Small Radial Turbomachinery: Part I — Compressor Impellers

2016 ◽  
Author(s):  
Dries Verstraete ◽  
Kjersti Lunnan
Keyword(s):  
Reynolds Number ◽  
Performance Analysis ◽  
Rotational Speed ◽  
Pressure Ratio ◽  
Unmanned Aircraft ◽  
Good Match ◽  
One Dimensional ◽  
Design Changes ◽  
Current Article ◽  
The Impact

Small unmanned aircraft are currently limited to flight ceilings below 20,000 ft due to the lack of an appropriate propulsion system. One of the most critical technological hurdles for an increased flight ceiling of small platforms is the impact of reduced Reynolds number conditions at altitude on the performance of small radial turbomachinery. The current article investigates the influence of Reynolds number on the efficiency and pressure ratio of two small centrifugal compressor impellers using a one-dimensional meanline performance analysis code. The results show that the efficiency and pressure ratio of the 60 mm baseline compressor at the design rotational speed drops with 6–9% from sea-level to 70,000 ft. The impact on the smaller 20 mm compressor is slightly more pronounced and amounts to 6–10%. Off-design changes at low rotational speeds are significantly higher and can amount to up to 15%. Whereas existing correlations show a good match for the efficiency drop at the design rotational speed, they fail to predict efficiency changes with rotational speed. A modified version is therefore proposed.

scholarly journals Physicochemical Properties and In Vitro Dissolution of Spiramycin Microparticles Using the Homogenate-Antisolvent Precipitation Process

2016 ◽  
Vol 7 (1) ◽  
pp. 10 ◽  
Author(s):  
Xiaonan Zhang ◽  
Xia Wu ◽  
Fengying Xie ◽  
Zhongjiang Wang ◽  
Xiuling Zhang ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
In Vitro Dissolution ◽  
Precipitation Process ◽  
Antisolvent Precipitation

Production of quicklime from Ashaka limestone through calcination process

2021 ◽  
Vol 1 (2) ◽  
pp. 041-048
Author(s):  
Benson Chinweuba Udeh
Keyword(s):  
Particle Size ◽  
Critical Value ◽  
Operating Conditions ◽  
Quadratic Model ◽  
Particle Sizes ◽  
Calcination Process ◽  
Process Effects ◽  
Effects Of Temperature ◽  
The Difference ◽  
The Relationship

This study is on the production of quicklime from Ashaka limestone through calcination process. Effects of temperature, particle size and time on quicklime yield were determined. The experiment was carried out at temperatures of 800, 900, 1000, 1100 and 1200 0C, particle sizes of 80mm, 90mm, 100mm, 300mm and 425mm and times of 0.5hr, 1hr, 2hrs, 3hrs and 4hrs. Analyses of the results showed that quicklime was successfully produced from Ashaka limestone through the calcination process. Quadratic model adequately described the relationship between quicklime yield and calcination factors of temperature, particle size and time. Recorded model F-value of 134.35 implies that the model is significant. The predicted R² of 0.9597 is in reasonable agreement with the adjusted R² of 0.9844; the difference is less than the critical value of 0.2. Optimum yield of 73.48% was obtained at optima operating conditions; temperature of 1000 0C, particle size of 90 µm and time of 3 hrs.

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