Waltham, MA, United States
Waltham, MA, United States

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Dittler I.,ZHAW Zurich University of Applied Sciences | Dornfeld W.,Levitronix | Schob R.,Levitronix | Cocke J.,SOPAT Ltd | And 3 more authors.
Journal of Visualized Experiments | Year: 2015

Pumps are mainly used when transferring sterile culture broths in biopharmaceutical and biotechnological production processes. However, during the pumping process shear forces occur which can lead to qualitative and/or quantitative product loss. To calculate the mechanical stress with limited experimental expense, an oil-water emulsion system was used, whose suitability was demonstrated for drop size detections in bioreactors1. As drop breakup of the oil-water emulsion system is a function of mechanical stress, drop sizes need to be counted over the experimental time of shear stress investigations. In previous studies, the inline endoscopy has been shown to be an accurate and reliable measurement technique for drop size detections in liquid/liquid dispersions. The aim of this protocol is to show the suitability of the inline endoscopy technique for drop size measurements in pumping processes. In order to express the drop size, the Sauter mean diameter d32 was used as the representative diameter of drops in the oil-water emulsion. The results showed low variation in the Sauter mean diameters, which were quantified by standard deviations of below 15%, indicating the reliability of the measurement technique. © 2015 Journal of Visualized Experiments.


Dittler I.,ZHAW Zurich University of Applied Sciences | Dornfeld W.,Levitronix | Schob R.,Levitronix | Cocke J.,SOPAT Ltd | And 3 more authors.
Journal of visualized experiments : JoVE | Year: 2015

Pumps are mainly used when transferring sterile culture broths in biopharmaceutical and biotechnological production processes. However, during the pumping process shear forces occur which can lead to qualitative and/or quantitative product loss. To calculate the mechanical stress with limited experimental expense, an oil-water emulsion system was used, whose suitability was demonstrated for drop size detections in bioreactors(1). As drop breakup of the oil-water emulsion system is a function of mechanical stress, drop sizes need to be counted over the experimental time of shear stress investigations. In previous studies, the inline endoscopy has been shown to be an accurate and reliable measurement technique for drop size detections in liquid/liquid dispersions. The aim of this protocol is to show the suitability of the inline endoscopy technique for drop size measurements in pumping processes. In order to express the drop size, the Sauter mean diameter d32 was used as the representative diameter of drops in the oil-water emulsion. The results showed low variation in the Sauter mean diameters, which were quantified by standard deviations of below 15%, indicating the reliability of the measurement technique.


PubMed | Levitronix, SOPAT Ltd., TU Berlin and ZHAW Zurich University of Applied Sciences
Type: | Journal: Journal of visualized experiments : JoVE | Year: 2015

Pumps are mainly used when transferring sterile culture broths in biopharmaceutical and biotechnological production processes. However, during the pumping process shear forces occur which can lead to qualitative and/or quantitative product loss. To calculate the mechanical stress with limited experimental expense, an oil-water emulsion system was used, whose suitability was demonstrated for drop size detections in bioreactors(1). As drop breakup of the oil-water emulsion system is a function of mechanical stress, drop sizes need to be counted over the experimental time of shear stress investigations. In previous studies, the inline endoscopy has been shown to be an accurate and reliable measurement technique for drop size detections in liquid/liquid dispersions. The aim of this protocol is to show the suitability of the inline endoscopy technique for drop size measurements in pumping processes. In order to express the drop size, the Sauter mean diameter d32 was used as the representative diameter of drops in the oil-water emulsion. The results showed low variation in the Sauter mean diameters, which were quantified by standard deviations of below 15%, indicating the reliability of the measurement technique.


Donis R.,Air Liquide | Fisher M.,Air Liquide | Bauck L.,Levitronix
ECS Transactions | Year: 2010

Slurry health has been shown to impact detectivity in the chemical mechanical planarization (CMP) process. Improper mechanical handling is known to form large agglomerates in CMP slurries that can lead to increased scratching of the surface. The foremost cause of slurry damage occurs from shear stresses placed on the slurry particles as they pass through the motive force in a distribution system. This paper is a study of two common slurry pumping methods and their contribution to post CMP micro-scratch defects measured on TEOS, Black Diamond 1 (BD 1), Cu blanket wafers, and low-k/Cu integrated patterned wafers. The two specific slurry handling methods studied were the recirculation of slurry in a distribution system by positive displacement (diaphragm) pumps and bearingless centrifugal pump systems. ©The Electrochemical Society.


Wu Z.J.,University of Maryland Baltimore County | Gellman B.,Thoratec Corporation | Zhang T.,University of Maryland Baltimore County | Taskin M.E.,University of Maryland Baltimore County | And 2 more authors.
Cardiovascular Engineering and Technology | Year: 2011

The pediatric pump-lung (PediPL) is a miniaturized integrated pediatric pump-oxygenator specifically designed for cardiac or cardiopulmonary support for patients weighing 5-20 kg to allow mobility and extended use for 30 days. The PediPL incorporates a magnetically levitated impeller with uniquely configured hollow fiber membranes (HFMs) into a single unit capable of performing both pumping and gas exchange. A combined computational and experimental study was conducted to characterize the functional and hemocompatibility performances of this newly developed device. The three-dimensional flow features of the PediPL and its hemolytic characteristics were analyzed using computational fluid dynamics based modeling. The oxygen exchange was modeled based on a convection-diffusion-reaction process. The HFMs were modeled as a porous medium which incorporates the flow resistance in the bundle by an added momentum sink term. The pumping function was evaluated for the required range of operating conditions (0.5-2.5 L/min and 1000-3000 rpm). The blood damage potentials were further analyzed in terms of flow and shear stress fields, and the calculations of hemolysis index. In parallel, the hydraulic pump performance, oxygen transfer, and hemolysis level were quantified experimentally. Based on the computational and experimental results, the PediPL is found to be functional to provide necessary oxygen transfer and blood pumping requirements for the pediatric patients. Smooth blood flow characteristics and low blood damage potential were observed in the entire device. The in vitro tests further confirmed that the PediPL can provide adequate blood pumping and oxygen transfer over the range of intended operating conditions with acceptable hemolytic performance. The rated flow rate for oxygenation is 2.5 L/min. The normalized index of hemolysis is 0.065 g/100 L at 1.0 L/min and 3000 rpm. © 2011 Biomedical Engineering Society.


Trademark
Thoratec Llc and Levitronix | Date: 2010-11-23

rotary pumps for liquids. circulatory assist devices, namely, blood pumps and associated controls for stabilizing blood flow for providing circulatory support during cardiac intervention; percutaneous assist devices, namely, blood pumps, cannulae and associated controls for connection to a circulatory system via cannulae inserted through the skin for stabilizing blood flow and providing circulatory support during cardiac intervention; implantable assist devices, namely, blood pumps and associated controls for implantation in a patient.

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