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S Pushpavanam - One of the best experts on this subject based on the ideXlab platform.

  • performance comparison of liquid liquid extraction in parallel microflows
    Industrial & Engineering Chemistry Research, 2014
    Co-Authors: A S Fabiya, Jaso R Picardo, S Pushpavanam
    Abstract:

    Parallel bicontinuous flows, which include stratified and core-annular flow, have applications in liquid–liquid extraction in microchannels. The flow regime has a significant impact on interphase mass transfer. Either stratified flow or core-annular flow can result in better extraction, depending on the physical properties of the fluids and solute and the operating conditions. In this work, we systematically compare the extraction performance of core-annular and stratified flow. Mathematical models are developed for each flow regime and solved semianalytically. Both models are validated with experimental data from the literature. Using the models we analyze both flow regimes across the parameter space. Two basis for comparison are used: (i) specified flow rates of the two fluid streams and (ii) specified pressure gradient and Holdup (Volume fraction of the carrier stream). For core-annular flow, two distinct cases are analyzed based on the position of the solute bearing carrier stream: (i) the carrier str...

  • Performance Comparison of Liquid–Liquid Extraction in Parallel Microflows
    Industrial & Engineering Chemistry Research, 2014
    Co-Authors: Anil B. Vir, Jaso R Picardo, A. S. Fabiyan, S Pushpavanam
    Abstract:

    Parallel bicontinuous flows, which include stratified and core-annular flow, have applications in liquid–liquid extraction in microchannels. The flow regime has a significant impact on interphase mass transfer. Either stratified flow or core-annular flow can result in better extraction, depending on the physical properties of the fluids and solute and the operating conditions. In this work, we systematically compare the extraction performance of core-annular and stratified flow. Mathematical models are developed for each flow regime and solved semianalytically. Both models are validated with experimental data from the literature. Using the models we analyze both flow regimes across the parameter space. Two basis for comparison are used: (i) specified flow rates of the two fluid streams and (ii) specified pressure gradient and Holdup (Volume fraction of the carrier stream). For core-annular flow, two distinct cases are analyzed based on the position of the solute bearing carrier stream: (i) the carrier str...

Syed S. H. Rizvi - One of the best experts on this subject based on the ideXlab platform.

  • RESIDENCE TIME DISTRIBUTION (RTD) AND GOODNESS OF MIXING (GM) DURING CO2‐INJECTION IN TWIN‐SCREW EXTRUSION PART I: RTD STUDIES
    Journal of Food Process Engineering, 1998
    Co-Authors: Bhajmohan Singh, Syed S. H. Rizvi
    Abstract:

    The residence-time distribution (RTD) studies are needed to characterize mixing conditions, flow patterns, and the extent of conversions and reactions of the biopolymers in any plasticating or cooking extruder. For the supercritical fluid extrusion process (SCFX), mixing of the fluid and starch-based biopolymers is an important step affecting cell nucleation and growth. RTD was studied in the mixing zone of the extruder, where CO 2 and gelatinized starch are brought together. Three levels of each of the process variables (screw speed and CO 2 injection pressure) were investigated, using specially designed apparatus for color-dye injection, and a die-restrictor to change the pressure profile and Holdup Volume in the extruder. Control RTD plots were for no CO 2 injection conditions at the same pressure, and the RTD of the full extruder section. Experimental RTDs were evaluated by: (1) the Wolf-White model, (2) a cascade of continuously stirred reactors (CSTR) model and (3) a model based on plug-flow in series with cascade of CSTRs. The last approach was most successful in capturing all aspects of the observed RTD curves including their tails. Injection of CO 2 at the highest pressure (110.3 bar) increased the RTD compared to no CO 2 -injection conditions. There were significant differences in the plug flow component of the RTD as well as differences in average residence time as a function of both screw speed and CO 2 injection pressure conditions.

  • RESIDENCE TIME DISTRIBUTION (RTD) AND GOODNESS OF MIXING (GM) DURING CO2-INJECTION IN TWIN-SCREW EXTRUSION PART I: RTD STUDIES
    Journal of Food Process Engineering, 1998
    Co-Authors: Bhajmohan Singh, Syed S. H. Rizvi
    Abstract:

    The residence-time distribution (RTD) studies are needed to characterize mixing conditions, flow patterns, and the extent of conversions and reactions of the biopolymers in any plasticating or cooking extruder. For the supercritical fluid extrusion process (SCFX), mixing of the fluid and starch-based biopolymers is an important step affecting cell nucleation and growth. RTD was studied in the mixing zone of the extruder, where CO 2 and gelatinized starch are brought together. Three levels of each of the process variables (screw speed and CO 2 injection pressure) were investigated, using specially designed apparatus for color-dye injection, and a die-restrictor to change the pressure profile and Holdup Volume in the extruder. Control RTD plots were for no CO 2 injection conditions at the same pressure, and the RTD of the full extruder section. Experimental RTDs were evaluated by: (1) the Wolf-White model, (2) a cascade of continuously stirred reactors (CSTR) model and (3) a model based on plug-flow in series with cascade of CSTRs. The last approach was most successful in capturing all aspects of the observed RTD curves including their tails. Injection of CO 2 at the highest pressure (110.3 bar) increased the RTD compared to no CO 2 -injection conditions. There were significant differences in the plug flow component of the RTD as well as differences in average residence time as a function of both screw speed and CO 2 injection pressure conditions.

Bhajmohan Singh - One of the best experts on this subject based on the ideXlab platform.

  • RESIDENCE TIME DISTRIBUTION (RTD) AND GOODNESS OF MIXING (GM) DURING CO2‐INJECTION IN TWIN‐SCREW EXTRUSION PART I: RTD STUDIES
    Journal of Food Process Engineering, 1998
    Co-Authors: Bhajmohan Singh, Syed S. H. Rizvi
    Abstract:

    The residence-time distribution (RTD) studies are needed to characterize mixing conditions, flow patterns, and the extent of conversions and reactions of the biopolymers in any plasticating or cooking extruder. For the supercritical fluid extrusion process (SCFX), mixing of the fluid and starch-based biopolymers is an important step affecting cell nucleation and growth. RTD was studied in the mixing zone of the extruder, where CO 2 and gelatinized starch are brought together. Three levels of each of the process variables (screw speed and CO 2 injection pressure) were investigated, using specially designed apparatus for color-dye injection, and a die-restrictor to change the pressure profile and Holdup Volume in the extruder. Control RTD plots were for no CO 2 injection conditions at the same pressure, and the RTD of the full extruder section. Experimental RTDs were evaluated by: (1) the Wolf-White model, (2) a cascade of continuously stirred reactors (CSTR) model and (3) a model based on plug-flow in series with cascade of CSTRs. The last approach was most successful in capturing all aspects of the observed RTD curves including their tails. Injection of CO 2 at the highest pressure (110.3 bar) increased the RTD compared to no CO 2 -injection conditions. There were significant differences in the plug flow component of the RTD as well as differences in average residence time as a function of both screw speed and CO 2 injection pressure conditions.

  • RESIDENCE TIME DISTRIBUTION (RTD) AND GOODNESS OF MIXING (GM) DURING CO2-INJECTION IN TWIN-SCREW EXTRUSION PART I: RTD STUDIES
    Journal of Food Process Engineering, 1998
    Co-Authors: Bhajmohan Singh, Syed S. H. Rizvi
    Abstract:

    The residence-time distribution (RTD) studies are needed to characterize mixing conditions, flow patterns, and the extent of conversions and reactions of the biopolymers in any plasticating or cooking extruder. For the supercritical fluid extrusion process (SCFX), mixing of the fluid and starch-based biopolymers is an important step affecting cell nucleation and growth. RTD was studied in the mixing zone of the extruder, where CO 2 and gelatinized starch are brought together. Three levels of each of the process variables (screw speed and CO 2 injection pressure) were investigated, using specially designed apparatus for color-dye injection, and a die-restrictor to change the pressure profile and Holdup Volume in the extruder. Control RTD plots were for no CO 2 injection conditions at the same pressure, and the RTD of the full extruder section. Experimental RTDs were evaluated by: (1) the Wolf-White model, (2) a cascade of continuously stirred reactors (CSTR) model and (3) a model based on plug-flow in series with cascade of CSTRs. The last approach was most successful in capturing all aspects of the observed RTD curves including their tails. Injection of CO 2 at the highest pressure (110.3 bar) increased the RTD compared to no CO 2 -injection conditions. There were significant differences in the plug flow component of the RTD as well as differences in average residence time as a function of both screw speed and CO 2 injection pressure conditions.

Patrick Favrod - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of Different Quality-Relevant Aspects of Closed System Transfer Devices (CSTDs).
    Pharmaceutical Research, 2020
    Co-Authors: Ahmed Besheer, Hanns-christian Mahler, Anja Matter-schwald, Sergio Mompart Barrenechea, Martin Vogt, Pascal Chalus, Pauline Heymes, Timothy Pillow, Andrea Kirste, Patrick Favrod
    Abstract:

    Health care professionals can be exposed to hazardous drugs such as cytostatics during preparation of drugs for administration. Closed sytem transfer devices (CSTDs) were introduced to provide protection for healthcare professional against unintended exposure to hazardous drugs. The interest in CSTDs has significantly increased after USP monograph was issued. The majority of the studies published so far on CSTDs have focused on their “containment” function. However, other important attributes for CSTDs with potential importance for product quality impact are not yet fully evaluated. In the current study, we evaluated four sytems from different suppliers, in combination with different container closure systems (CCS), using solutions of different viscosity and surface tension. The different CSTD / CCS combinations were tested for (a) containment (integrity) using a highly sensitive helium leak test, (b) the force required for mounting the vial adaptor, (c) contribution to visible and subvisible particles as well as (d) the hold-up Volume. Results show that the majority of CSTDs may have leaks varying in size, and that some of them generated visible particles due to stopper coring and subvisible particles, both due to silicon oil and particulate contaminations of the Devices. Finally, the Holdup Volume was up to 1 mL depending on the CSTD type, vial size and solution viscosity. These results show that there is a need to evaluate the compatibility of CSTD systems to select the best system for the intended use and that CSTDs may adversely impact product quality and delivered dose.

  • Evaluation of Different Quality-Relevant Aspects of Closed System Transfer Devices (CSTDs)
    Pharmaceutical Research, 2020
    Co-Authors: Ahmed Besheer, Hanns-christian Mahler, Anja Matter-schwald, Sergio Mompart Barrenechea, Martin Vogt, Pascal Chalus, Pauline Heymes, Timothy Pillow, Andrea Kirste, Patrick Favrod
    Abstract:

    Purpose Health care professionals can be exposed to hazardous drugs such as cytostatics during preparation of drugs for administration. Closed sytem transfer devices (CSTDs) were introduced to provide protection for healthcare professional against unintended exposure to hazardous drugs. The interest in CSTDs has significantly increased after USP monograph was issued. The majority of the studies published so far on CSTDs have focused on their “containment” function. However, other important attributes for CSTDs with potential importance for product quality impact are not yet fully evaluated. Methods In the current study, we evaluated four sytems from different suppliers, in combination with different container closure systems (CCS), using solutions of different viscosity and surface tension. The different CSTD / CCS combinations were tested for (a) containment (integrity) using a highly sensitive helium leak test, (b) the force required for mounting the vial adaptor, (c) contribution to visible and subvisible particles as well as (d) the hold-up Volume. Results Results show that the majority of CSTDs may have leaks varying in size, and that some of them generated visible particles due to stopper coring and subvisible particles, both due to silicon oil and particulate contaminations of the Devices. Finally, the Holdup Volume was up to 1 mL depending on the CSTD type, vial size and solution viscosity. Conclusion These results show that there is a need to evaluate the compatibility of CSTD systems to select the best system for the intended use and that CSTDs may adversely impact product quality and delivered dose.

A S Fabiya - One of the best experts on this subject based on the ideXlab platform.

  • performance comparison of liquid liquid extraction in parallel microflows
    Industrial & Engineering Chemistry Research, 2014
    Co-Authors: A S Fabiya, Jaso R Picardo, S Pushpavanam
    Abstract:

    Parallel bicontinuous flows, which include stratified and core-annular flow, have applications in liquid–liquid extraction in microchannels. The flow regime has a significant impact on interphase mass transfer. Either stratified flow or core-annular flow can result in better extraction, depending on the physical properties of the fluids and solute and the operating conditions. In this work, we systematically compare the extraction performance of core-annular and stratified flow. Mathematical models are developed for each flow regime and solved semianalytically. Both models are validated with experimental data from the literature. Using the models we analyze both flow regimes across the parameter space. Two basis for comparison are used: (i) specified flow rates of the two fluid streams and (ii) specified pressure gradient and Holdup (Volume fraction of the carrier stream). For core-annular flow, two distinct cases are analyzed based on the position of the solute bearing carrier stream: (i) the carrier str...