Agitation. Mass Transfer Coefficients in Liquid-Solid Agitation Systems

Hixson, Arthur W.; Baum, Sidney J.

doi:10.1021/ie50376a011

Cited by 106 publications

(62 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Hixson assumed d to be stagnant. [21] In this case, when considering a decrease in the particle size from 5 mm to 0.4 mm, Equation 2 can be rewritten as:…”

Section: Theoretical Increase Of Dissolution Ratementioning

confidence: 99%

“…The separation of nanosized particles from dissolved drug is much more challenging than for micronized or other particles, because of their much smaller size. One might be tempted to use the Nernst–Brunner equation () to calculate the dissolution rate according to the surface area of drug: if the particle size decreases from 5 µm to 0.4 µm, as is the case for fenofibrate particles in Lipidil Ter® in comparison with Lipidil 145 ONE®, this leads to an increase of surface area of 12.25, for a given dose [21,22] . This approach leads to the conclusion that the dissolution rate is directly proportional to the surface area.…”

Section: Introductionmentioning

confidence: 99%

“…While there is little reason to scrutinize the surface area, A Drug , the boundary layer, δ , has been subject to several studies. Hixson assumed δ to be stagnant [21] . In this case, when considering a decrease in the particle size from 5 µm to 0.4 µm, can be rewritten as:…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Analytical methods for dissolution testing of nanosized drugs

Jünemann

Dressman

2012

Journal of Pharmacy and Pharmacology

View full text Add to dashboard Cite

show abstract

“…Hixson assumed d to be stagnant. [21] In this case, when considering a decrease in the particle size from 5 mm to 0.4 mm, Equation 2 can be rewritten as:…”

Section: Theoretical Increase Of Dissolution Ratementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Analytical methods for dissolution testing of nanosized drugs

Jünemann

Dressman

2012

Journal of Pharmacy and Pharmacology

View full text Add to dashboard Cite

show abstract

“…Hixson and Baum [45] published mass transfer relations that illustrate the importance of the state of solids suspension. Below the status of complete suspension (complete motion of all particles) rising stirrer speed increases the accessible mass transfer area.…”

mentioning

confidence: 99%

The Development of Stirring Technology from an Empirical Art to Science

Kraume

2015

ChemBioEng Reviews

View full text Add to dashboard Cite

Until the beginning of the 20th century, stirring was mostly regarded only marginally in most production processes. A century later, many aspects of stirring technology have been largely understood scientifically. This paper presents ground-breaking publications which have contributed significantly to the impressive gains in scientific knowledge. Here, the focus is on work to determine the power consumption as well as to characterize liquid mixing, suspension of solids and dispersion of liquids and gases.

show abstract

“…Mass transfer between suspended particles and liquid is one of the most important factors in chemical and biochemical processes. Therefore, many correlations of solid-liquid mass transfer coefficients in a stirred vessel were reported (Asai et al, 1988, Calderbank and Moo-Young, 1961, Harriott, 1962, Hiraoka et al, 1990, Hixson, 1941, Kikuchi et al, 1987, Levins and Glastonbury, 1972and Miller, 1971. Rhodes and Gaden (1957) measured the solid-liquid mass transfer coefficients in a 500 mL shaking Erlenmeyer flask at limited operating conditions, i.e., the circulating frequencies of 3.2 and 4.0 s-l and the liquid volume of 50, 100 and 200 mL.…”

mentioning

confidence: 99%

Solid—liquid mass transfer in a shaking vessel for a bioreactor with “current pole”

et al. 1998

View full text Add to dashboard Cite

A shaking vessel with "current pole", which is a center pole installed at the bottom, had shorter mixing time than a shaking vessel with a cone at the bottom. The mass transfer rate on the suspended particles was also measured in the shaking vessel where ion-exchange resin beads were used as the suspended particles. The dependence of the solid-liquid mass transfer coefficient on the circulating frequency changed at the critical circulating frequency for complete suspension NJr For a circulating frequency higher than NJs, the mass transfer coefficient was correlated with the power consumption per unit volume, regardless of presence or not of the current pole.Le temps de melange dans un rCservoir oscillant muni d'un dCflecteur de courant (qui est une tige placCe au fond du rCservoir) est plus court que pour un rCservoir oscillant muni d'un cane install6 sur le fond. Le taux de transfert de niatikre des particules en suspension a Ct C mesure dans le rCservoir oscillant pour des billes de rbsine Cchangeuses d'ions. La dCpendance du coefficient de transfert de matibre solides-liquide par rapport B la vitesse de circulation change B la vitesse de circulation critique N . pour une suspension compkte. Pour une vitesse de circulation plus grande que NJs, le coefficient de transfert de mati&e a CtC corrClC B la consommation d'knergie volumique, en prCsence ou en l'absence de dkflecteur de courant.Keywords: mixing, shaking vessel, mass transfer, bioreactor, current pole.igh shear stress around the agitated impeller is not H acceptable to cell culture in stirred bioreactors. Nakashimada et al. (1995Nakashimada et al. ( , 1996 reported that the observed low efficiency of the regeneration of hairy root in an air-lift type bioreactor is attributed to bursting of bubble on the liquid surface. The resulting shear stress inflicted significant damage on the plantlet reducing the regeneration from the hairy root tips. Kato et al. (1995Kato et al. ( , 1996a reported that mixing in shaking vessel can eliminated the high shear stress in the reactor. Honda et al. (1997) obtained good results for mass-production of the regenerated plantlet with a shaking type bioreactor.In a previous paper (Kato et al., 1995), we observed that particles in the shaking vessel gathered at the center of the vessel bottom at a low circulating frequency, due to the generation of a stagnant point at the vessel bottom. To improve particle dispersion in impeller mixing, a cone is usually installed at the vessel bottom (Chudacek, 1985). In the previous paper (Kato et al., 1996b), "current pole", which is a center pole installed at the shaking vessel bottom as shown in Figure 1, was more effective than the cone for mixing in a shaking vessel. Effects of the pole on flow patterns, mixing time, and dispersion were also examined experimentally (Kato et al., 1996b). We applied the shaking vessel with the current pole to bioreactors for plant cells, and obtained better plantlet regeneration than that in an air-lift type bioreactor and a shaking vessel type bioreactor w...

show abstract

Agitation. Mass Transfer Coefficients in Liquid-Solid Agitation Systems

Cited by 106 publications

References 7 publications

Analytical methods for dissolution testing of nanosized drugs

Analytical methods for dissolution testing of nanosized drugs

The Development of Stirring Technology from an Empirical Art to Science

Solid—liquid mass transfer in a shaking vessel for a bioreactor with “current pole”

Contact Info

Product

Resources

About