Method of measuring cross-flow vortices by use of an array of hot-film sensors

The invention is a method for measuring the wavelength of cross-flow vortices of air flow having streamlines of flow traveling across a swept airfoil. The method comprises providing a plurality of hot-film sensors. Each hot-film sensor provides a signal which can be processed, and each hot-film sensor is spaced in a straight-line array such that the distance between successive hot-film sensors is less than the wavelength of the cross-flow vortices being measured. The method further comprises determining the direction of travel of the streamlines across the airfoil and positioning the straight-line array of hot film sensors perpendicular to the direction of travel of the streamlines, such that each sensor has a spanwise location. The method further comprises processing the signals provided by the sensors to provide root-mean-square values for each signal, plotting each root-mean-square value as a function of its spanwise location, and determining the wavelength of the cross-flow vortices by noting the distance between two maxima or two minima of root-mean-square values

Experimental studies on Goertler vortices

Goertler vortices arise in laminar boundary layers along concave walls due to an imbalance between pressure and centrifugal forces. In advanced laminar-flow control (LFC) supercritical airfoil designs, boundary-layer suction is primarily used to control Tollmien-Schlichting instability and cross-flow vortices in the concave region near the leading edge of the airfoil lower surface. The concave region itself is comprised of a number of linear segments positioned to limit the total growth of Goertler vortices. Such an approach is based on physical reasonings but rigorous theoretical justification or experimental evidence to support such an approach does not exist. An experimental project was initiated at NASA Langley to verify this concept. In the first phase of the project an experiment was conducted on an airfoil whose concave region has a continuous curvature distribution. Some results of this experiment were previously reported and significant features are summarized

Population Pharmacokinetic Analysis of Centrally Acting Drugs Metabolized by CYP2D6

A simple, sensitive, and reliable UPLC method has been developed and validated for simultaneous determination of risperidone, 9-hydroxyrisperidone and olanzapine in human plasma in vitro. • The developed method has been successfully adopted to evaluate the pharmacokinetic parameters of second generation antipsychotic drugs, risperidone and its major metabolite, 9-hydroxyrisperidone, in human plasma. • The distributions of normal, intermediate and poor metabolizers were found to be 70%, 25% and 5% respectively. The allelic frequencies of all SNP were in Hardy-Weinberg equilibrium (P ≥ 0.05). • The metabolic ratio was higher in intermediate metabolizers (2.04 ± 0.20) as compared to normal metabolizers (1.40 ± 0.22). • The pharmacokinetic parameters (Cmax, AUC0-t, T1/2 and CL) of active moiety were found to be significant in normal and intermediate metabolizers. • Poor metabolizers exhibited a higher prevalence of CNS (P = 0.001), CVS (P < 0.001), dizziness (P = 0.005), hypotension (P = 0.01) and GIT (P = 0.01) as compared to normal metabolizers. • Our data supports these above conclusions in our sample population, i.e., poor metabolizers require half the risperidone dose than that for normal metabolizers to reduce the incidence of adverse effects. CONCLUSION: In the current study, we have demonstrated significant association between the genotype status and pharmacokinetic parameter of normal subjects from our locale in South India with respect to the CYP2D6*10 genotype. Our data suggest that CYP2D6*10 polymorphism have significant association between risperidone and 9-hydroxyrisperidone pharmacokinetics. Active moiety is highly predictive of the clinical response to risperidone in healthy volunteers, which is dependent on the CYP2D6*10 genotype status. Additionally, we demonstrated that using NONMEM and multi-compartment mixed effect modelling of the population pharmacokinetics of risperidone and its metabolite, genotype has a major influence on determining the plasma concentrations of both risperidone and 9- hydroxyrisperidone. The pharmacogenetic variations in clearance of the risperidone and 9-hydroxyrisperidone may be due to differential expressions of CYP2D6 in intestinal epithelium in different genotypes of CYP2D6*10 allele. Further, this could be applied to clinical decision making such as determination of dosing intervals. We recommend that the dose of risperidone in slow metabolizers must be less that used in normal metabolizers, though it has to be confirmed in further studies in our population

Long-term electrode behavior during treatment of arsenic contaminated groundwater by a pilot-scale iron electrocoagulation system.

Iron electrocoagulation (Fe-EC) is an effective technology to remove arsenic (As) from groundwater used for drinking. A commonly noted limitation of Fe-EC is fouling or passivation of electrode surfaces via rust accumulation over long-term use. In this study, we examined the effect of removing electrode surface layers on the performance of a large-scale (10,000 L/d capacity) Fe-EC plant in West Bengal, India. We also characterized the layers formed on the electrodes in active use for over 2 years at this plant. The electrode surfaces developed three distinct horizontal sections of layers that consisted of different minerals: calcite, Fe(III) precipitates and magnetite near the top, magnetite in the middle, and Fe(III) precipitates and magnetite near the bottom. The interior of all surface layers adjacent to the Fe(0) metal was dominated by magnetite. We determined the impact of surface layer removal by mechanical abrasion on Fe-EC performance by measuring solution composition (As, Fe, P, Si, Mn, Ca, pH, DO) and electrochemical parameters (total cell voltage and electrode interface potentials) during electrolysis. After electrode cleaning, the Fe concentration in the bulk solution increased substantially from 15.2 to 41.5 mg/L. This higher Fe concentration led to increased removal of a number of solutes. For As, the concentration reached below the 10 μg/L WHO MCL more rapidly and with less total Fe consumed (i.e. less electrical energy) after cleaning (128.4 μg/L As removed per kWh) compared to before cleaning (72.9 μg/L As removed per kWh). Similarly, the removal of P and Si improved after cleaning by 0.3 mg/L/kWh and 1.1 mg/L/kWh, respectively. Our results show that mechanically removing the surface layers that accumulate on electrodes over extended periods of Fe-EC operation can restore Fe-EC system efficiency (concentration of solute removed/kWh delivered). Since Fe release into the bulk solution substantially increased upon electrode cleaning, our results also suggest that routine electrode maintenance can ensure robust and reliable Fe-EC performance over year-long timescales