scholarly journals Quantitative investigation of particle formation of a model pharmaceutical formulation using single droplet evaporation experiments and X-ray tomography

2018 ◽  
Vol 29 (12) ◽  
pp. 2996-3006 ◽  
Author(s):  
Frederik J.S. Doerr ◽  
Iain D.H. Oswald ◽  
Alastair J. Florence
Keyword(s):  
Droplet Evaporation ◽  
Particle Formation ◽  
Pharmaceutical Formulation ◽  
Single Droplet ◽  
Quantitative Investigation ◽  
X Ray

scholarly journals Evaluation of the Performance of the Drag Force Model in Predicting Droplet Evaporation for R134a Single Droplet and Spray Characteristics for R134a Flashing Spray

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4618
Author(s):  
Zhi-Fu Zhou ◽  
Dong-Qing Zhu ◽  
Guan-Yu Lu ◽  
Bin Chen ◽  
Wei-Tao Wu ◽  
...  
Keyword(s):  
Drag Force ◽  
Droplet Diameter ◽  
Radial Distance ◽  
Droplet Evaporation ◽  
Nozzle Diameter ◽  
Force Model ◽  
Straight Tube ◽  
Single Droplet ◽  
Spray Characteristics ◽  
Two Phase

Drag force plays an important role in determining the momentum, heat and mass transfer of droplets in a flashing spray. This paper conducts a comparative study to examine the performance of drag force models in predicting the evolution of droplet evaporation for R134a single droplet and spray characteristics for its flashing spray. The study starts from single moving R134a droplet vaporizing in atomispheric environment, to a fully turbulent, flashing spray caused by an accidental release of high-pressure R134a liquid in the form of a straight-tube nozzle, using in-house developed code and a modified sprayFoam solver in OpenFOAM, respectively. The effect of the nozzle diameter on the spray characteristics of R134a two-phase flashing spray is also examined. The results indicate that most of the drag force models have little effect on droplet evporation in both single isolated droplet modelling and fully two-phase flashing spray simulation. However, the Khan–Richardson model contributes to different results. In particular, it predicts a much different profile of the droplet diameter distribution and a much lower droplet temperature in the radial distance. The nozzle diameter has a significant impact on the flashing spray. A smaller diameter nozzle leads to more internse explosive atomization, shorter penetration distance, lower droplet diameter and velocity, and a faster temperature decrease.

Quantitative investigation of phase retrieval from x-ray phase-contrast tomographic images

2008 ◽  
Author(s):  
H. O. Moser ◽  
K. Banas ◽  
A. Chen ◽  
T. Vo Nghia ◽  
L. K. Jian ◽  
...  
Keyword(s):  
Phase Contrast ◽  
Phase Retrieval ◽  
Quantitative Investigation ◽  
Tomographic Images ◽  
X Ray

Crystal structures of the flavonoid Oroxylin A and the regioisomers Negletein and Wogonin

2020 ◽  
Vol 76 (5) ◽  
pp. 490-499
Author(s):  
Ruel Valerio Robles De Grano ◽  
Elena V. Vashchenko ◽  
Madiha Nisar ◽  
Herman H.-Y. Sung ◽  
Valerii V. Vashchenko ◽  
...  
Keyword(s):  
Low Temperature ◽  
Crystal Structures ◽  
Pharmaceutical Formulation ◽  
Oroxylin A ◽  
X Ray ◽  
First Time

The flavonoid Oroxylin A (6-methoxychrysin or 5,7-dihydroxy-6-methoxy-2-phenyl-4H-chromen-4-one, C16H12O5) and its regioisomers are of increasing interest for a variety of bioactive functions and their pharmaceutical formulation is of importance. Previous difficulties in the separation and misidentification of Oroxylin A from its regioisomers Wogonin (8-methoxychrysin or 5,7-dihydroxy-8-methoxy-2-phenyl-4H-chromen-4-one) and Negletein (5,6-dihydroxy-7-methoxyflavone or 5,6-dihydroxy-7-methoxy-2-phenyl-4H-chromen-4-one) render its full structural and powder X-ray characterization highly desirable. The low-temperature (100 K) crystal structures of Oroxylin A, Negletein and Wogonin sesquihydrate are reported for the first time. Wogonin crystallizes in two related but distinct hydrated forms. These have very similar powder diffractograms, indicating that such issues need to be addressed for its pharmaceutical formulation.

Sign in / Sign up

Export Citation Format

Share Document