Base Unit (base + unit)

Distribution by Scientific Domains


Selected Abstracts


Ba2Ti2Si2O9F2, a new titanium silicate

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2009
Matthew Mann
Dibarium dititanium difluoride dioxide heptaoxidodisilicate, Ba2Ti2Si2O9F2, is a new edge-sharing titanate with a unique titanium silicate framework. All atoms in the structure are in general positions. Titanium oxyfluoride octahedra combine with silicon tetrahedra to form a double stacked chain, which is the base unit of the layered framework. The Ba atoms lie in channels that extend along the a axis. [source]


Patient Satisfaction With the External Equipment of Implantable Left Ventricular Assist Devices

ARTIFICIAL ORGANS, Issue 9 2010
Anna L. Meyer
Abstract Patient satisfaction with left ventricular assist device (LVAD) external equipment has not yet been reported. We aimed to evaluate the quality of two different systems based on patients' perspective and its interrelationship with quality of life. Differential assessment of the HeartMate II axial flow pump (n = 17; Thoratec, Pleasanton, CA, USA) and the HVAD centrifugal pump (n = 10; HeartWare, Inc., Miramar, FL, USA) was obtained from 27 outpatients by a questionnaire 2 months to 2.9 years after device implantation. In addition, a health-related quality of life questionnaire (Short Form-36 [SF-36]) was completed. Overall patients' satisfaction was high. Severe limitations were attributed to the loudness of the power base unit in HeartMate II patients (P = 0.00), and HVAD patients were dissatisfied by the length of the driveline (P = 0.02). Between HVAD and HeartMate II patients, no significant differences in the quality of life (assessed by SF-36) were reported. While the overall satisfaction of outpatients on LVAD support was high, differences between the systems were found. Patients' perspectives may have an important impact on future modification of external components. Ultimately, this may also contribute to an improvement in the quality of life of chronic LVAD patients. [source]


Effect of machine compliance on mold deflection during injection and packing of thermoplastic parts

POLYMER ENGINEERING & SCIENCE, Issue 7 2006
Brian Carpenter
Minimizing mold deflection is essential when manufacturing plastic parts to tight tolerances. Both the mold and the machine are compliant and deform upon loading, which can affect the part quality. Therefore, understanding mold deflection during injection molding is critical for determining the final geometry of the part. It is also critical for secondary processes such as the in-mold coating process. This article presents work in quantifying both mold deflection during an injection-molding cycle and the effect of machine compliance on mold behavior. The mold cavity pressure obtained using MoldFlowÔ was used as input for the subsequent finite element mold deflection analysis. Two different structural models were used: the first model included only the mold, the mold base units and the ejector platen; the second model included the effect of the injection-molding machine compliance. To validate the model, strain gage rosettes were placed on the mold and the machine. Validating experiments were conducted using process parameters identical to those used in the simulations. A comparison of the experimental and simulation results for both models is presented. POLYM. ENG. SCI., 46:844,852, 2006. © 2006 Society of Plastics Engineers [source]


Modulation of the Aerobic Oxidative Polymerization in Phenylazomethine Dendrimers Assembling Copper Complexes

CHEMISTRY - A EUROPEAN JOURNAL, Issue 36 2010
Dr. Takane Imaoka
Abstract The aerobic oxidative polymerization of phenol derivatives can provide poly(phenylene oxide)s, which are known as engineering plastics. This oxidation can be carried out with atmospheric oxygen molecules as the oxidizing reagent in the presence of copper complexes as the catalyst; however, stoichiometric or excess amounts of bases are also generally required. By using a phenylazomethine dendrimer complexed with several equivalent amounts of copper chloride, the additive (base)-free polymerization of 2,6-difluorophenol was successful with a very small amount of the catalyst (0.7,mol,% of copper for the monomer) because the dendrimer was composed of many Schiff base units, affording a base and catalyst (copper complex) condensed reaction field. The resulting polymer was nearly linear and the molecular weight was very high. When the equimolar amount of the copper complex in one dendrimer molecule was increased, the polymer obtained under this reaction condition was rather branched, resulting in a higher glass transition temperature. [source]