Experimental and Numerical Investigations of Profile and Secondary Aerodynamic Losses in High Pressure Axial Turbines

A series of experimental studies were conducted in order to investigate the generation and growth of A series of experimental studies were conducted in order to investigate the generation and growth of aerodynamic losses in high pressure axial turbine stages. A two-dimensional linear blade cascade facility was utilized with two sets of blade designs to examine the effects of varying the flow incidence angle as well as the cascade stagger angle on the profile loss component and the blade loading. Experimental findings were compared to CFD results and empirical correlations from literature. A two-stage research axial turbine was assembled with a set of bowed stator and twisted rotor blades to study the three-dimensional aerodynamic losses at design and off-design operations. Extensive performance tests were carried out to create the full efficiency map of the turbine, while detailed interstage measurements resolved the complete flow field of the second stage. The radial distribution of the various flow parameters within the stator and rotor rows enabled accurately calculating the losses, which were compared to steady and transient CFD results. Findings from these experimental investigations were implemented into a generic streamline curvature method solver that inviscidly solves the radial equilibrium equations, and provides additional corrections for profile, secondary, trailing edge and seal leakage aerodynamic losses using empirical correlations to help predict the overall performance of axial turbines at various operating conditions

Differential toxicity of gold-doxorubicin in cancer cells vs. cardiomyocytes as measured by real-time growth assays and fluorescence lifetime imaging microscopy (FLIM)

The kinetics of toxicity of doxorubicin (Dox) and gold nanoparticle-conjugated doxorubicin (Au-Dox) were investigated in cultured B16 melanoma cells and cardiomyocytes using real-time cell-growth imaging. Both bolus exposure and continuous exposure were used. Modeling of the growth curve dynamics suggested patterns of uptake and/or expulsion of the drug that were different for the different cell lines and exposures. Dox alone in B16 cells fit to a model of slow drug buildup, whereas Au-Dox fit to a pattern of initial high drug efficacy followed by a decrease. In cardiomyocytes, the best fit was to a model of increasing drug concentration which then began to decrease, consistent with breakdown of the doxorubicin in solution. Cardiomyocytes were more sensitive than B16 cells to Dox alone (IC_(50) 123 ± 2 nM vs. 270 ± 2 nM with continuous exposure), but were dramatically less sensitive to Au-Dox (IC_(50) 1 ± 0.1 μM vs. 58 ± 5 nM with continuous exposure). Bolus exposure for 40 min led to significant cell death in B16 cells but not in cardiomyocytes. Fluorescence lifetime imaging (FLIM) showed different patterns of uptake of Au-Dox in the two cell types that explained the differential toxicity. While Au-Dox concentrated in the nuclei of B16 cells, it remained endosomal in cardiomyocytes. These results suggest that stable conjugates of nanoparticles to doxorubicin may be useful for treating resistant cancers while sparing healthy tissue

InP/ZnS as a safer alternative to CdSe/ZnS core/shell quantum dots: in vitro and in vivo toxicity assessment

We show that water soluble InP/ZnS core/shell QDs are a safer alternative to CdSe/ZnS QDs for biological applications, by comparing their toxicity in vitro (cell culture) and in vivo (animal model Drosophila). By choosing QDs with comparable physical and chemical properties, we find that cellular uptake and localization are practically identical for these two nanomaterials. Toxicity of CdSe/ZnS QDs appears to be related to the release of poisonous Cd(2+) ions and indeed we show that there is leaching of Cd(2+) ions from the particle core despite the two-layer ZnS shell. Since an almost identical amount of In(III) ions is observed to leach from the core of InP/ZnS QDs, their very low toxicity as revealed in this study hints at a much lower intrinsic toxicity of indium compared to cadmium

Experimental and Numerical Investigations of Profile and Secondary Aerodynamic Losses in High Pressure Axial Turbines

A series of experimental studies were conducted in order to investigate the generation and growth of A series of experimental studies were conducted in order to investigate the generation and growth of aerodynamic losses in high pressure axial turbine stages. A two-dimensional linear blade cascade facility was utilized with two sets of blade designs to examine the effects of varying the flow incidence angle as well as the cascade stagger angle on the profile loss component and the blade loading. Experimental findings were compared to CFD results and empirical correlations from literature. A two-stage research axial turbine was assembled with a set of bowed stator and twisted rotor blades to study the three-dimensional aerodynamic losses at design and off-design operations. Extensive performance tests were carried out to create the full efficiency map of the turbine, while detailed interstage measurements resolved the complete flow field of the second stage. The radial distribution of the various flow parameters within the stator and rotor rows enabled accurately calculating the losses, which were compared to steady and transient CFD results. Findings from these experimental investigations were implemented into a generic streamline curvature method solver that inviscidly solves the radial equilibrium equations, and provides additional corrections for profile, secondary, trailing edge and seal leakage aerodynamic losses using empirical correlations to help predict the overall performance of axial turbines at various operating conditions

Experimental and Numerical Investigations of Profile and Secondary Aerodynamic Losses in High Pressure Axial Turbines

A series of experimental studies were conducted in order to investigate the generation and growth of A series of experimental studies were conducted in order to investigate the generation and growth of aerodynamic losses in high pressure axial turbine stages. A two-dimensional linear blade cascade facility was utilized with two sets of blade designs to examine the effects of varying the flow incidence angle as well as the cascade stagger angle on the profile loss component and the blade loading. Experimental findings were compared to CFD results and empirical correlations from literature. A two-stage research axial turbine was assembled with a set of bowed stator and twisted rotor blades to study the three-dimensional aerodynamic losses at design and off-design operations. Extensive performance tests were carried out to create the full efficiency map of the turbine, while detailed interstage measurements resolved the complete flow field of the second stage. The radial distribution of the various flow parameters within the stator and rotor rows enabled accurately calculating the losses, which were compared to steady and transient CFD results. Findings from these experimental investigations were implemented into a generic streamline curvature method solver that inviscidly solves the radial equilibrium equations, and provides additional corrections for profile, secondary, trailing edge and seal leakage aerodynamic losses using empirical correlations to help predict the overall performance of axial turbines at various operating conditions

Higher Order Combustion Instability Corrections for Solid Rocket Motors

Acoustic instability is currently viewed as one of the major challenges facing Solid Rocket Motor (SRM) developers. Unaccounted for, this phenomenon can induce undesirable pressure waves traveling in both longitudinal and transverse directions inside a rocket combustion chamber. Whenever the amplitude of these waves becomes large, intense vibrations and fluctuating loads can be experienced. These undesirable oscillations can lead to structural damage or outright motor failure. This work constitutes a follow-up to a recent study by Flandro and Majdalani 39 who have analyzed the linear aspects of this problem earlier last year. The current study builds on what their work has established, and expands the results that they have produced. The main benefit lies in the addition of few new terms which help to improve our predictive capabilities using explicit integral expressions. The current work considers two combustion chamber geometries. These correspond to the cylindrical and rectangular port perforations associated with an internal burning cylinder and slab motors, respectively. This study not only provides accurate and reliable approximations, but goes further to study the effects of key chamber parameters and their bearing on stability

Synthèse rapide et performante des méthylène diphosphates de Di, Tri et tétraglycosyle

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Experimental and Numerical Investigations of Profile and Secondary Aerodynamic Losses in High Pressure Axial Turbines

A series of experimental studies were conducted in order to investigate the generation and growth of A series of experimental studies were conducted in order to investigate the generation and growth of aerodynamic losses in high pressure axial turbine stages. A two-dimensional linear blade cascade facility was utilized with two sets of blade designs to examine the effects of varying the flow incidence angle as well as the cascade stagger angle on the profile loss component and the blade loading. Experimental findings were compared to CFD results and empirical correlations from literature. A two-stage research axial turbine was assembled with a set of bowed stator and twisted rotor blades to study the three-dimensional aerodynamic losses at design and off-design operations. Extensive performance tests were carried out to create the full efficiency map of the turbine, while detailed interstage measurements resolved the complete flow field of the second stage. The radial distribution of the various flow parameters within the stator and rotor rows enabled accurately calculating the losses, which were compared to steady and transient CFD results. Findings from these experimental investigations were implemented into a generic streamline curvature method solver that inviscidly solves the radial equilibrium equations, and provides additional corrections for profile, secondary, trailing edge and seal leakage aerodynamic losses using empirical correlations to help predict the overall performance of axial turbines at various operating conditions

Real-Time Detection of Staphylococcus Aureus Using Whispering Gallery Mode Optical Microdisks

Whispering Gallery Mode (WGM) microresonators have recently been studied as a means to achieve real-time label-free detection of biological targets such as virus particles, specific DNA sequences, or proteins. Due to their high quality (Q) factors, WGM resonators can be highly sensitive. A biosensor also needs to be selective, requiring proper functionalization of its surface with the appropriate ligand that will attach the biomolecule of interest. In this paper, WGM microdisks are used as biosensors for detection of Staphylococcus aureus. The microdisks are functionalized with LysK, a phage protein specific for staphylococci at the genus level. A binding event on the surface shifts the resonance peak of the microdisk resonator towards longer wavelengths. This reactive shift can be used to estimate the surface density of bacteria that bind to the surface of the resonator. The limit of detection of a microdisk with a Q-factor around 104 is on the order of 5 pg/mL, corresponding to 20 cells. No binding of Escherichia coli to the resonators is seen, supporting the specificity of the functionalization scheme