Acoustics-turbulence interaction

An investigation of the instability frequency was undertaken. Measurements revealed that the hot wire probe induces and sustains stable upstream oscillation of the free shear layer. The characteristics of the free shear layer tone are found to be different from the slit jet wedge edgetone phenomenon. The shear tone induced by a plane wedge in a plane free shear layer was then examined in order to further document the phenomenon. The eigenvalues and eigenfunctions of the tone fundamental show agreement with the spatial stability theory. A comprehensive summary of the results is also included

Vinorelbine with or without Trastuzumab in Metastatic Breast Cancer: A Retrospective Single Institution Series

Background. We report our experience with vinorelbine, a widely used chemotherapeutic, in unselected metastatic breast cancer patients treated in clinical routine. Patients and Methods. The data of all patients with metastatic breast cancer receiving vinorelbine with or without trastuzumab during a six year period were reviewed. Patients received vinorelbine intravenous 25-30 mg/m(2) or 60-80 mg/m(2) orally in days 1 and 8 of a 21 day cycle. Results. Eighty-seven women were included. Sixty-two patients received vinorelbine alone and 25 patients received vinorelbine in combination with trastuzumab. In 67 patients this was the first line treatment for metastatic disease and in 20 patients it was 2nd or later line of treatment. The median TTP was six months (range: 1-45). The median overall survival was 11.5 months (range: 1-83). Seventy patients were evaluable for response. In patients receiving first line treatment 44.4% had a response while in the second and subsequent lines setting 12.5% of patients responded (P = 0.001). Objective response was obtained in 63.6% of patients receiving concomitant trastuzumab and in 25% of patients receiving vinorelbine alone (P = 0.0002). Conclusion. This study confirms a high disease control rate. Response rate and TTP were superior in first line treatment compared to subsequent lines

Interface modification of clay and graphene platelets reinforced epoxy nanocomposites: a comparative study

The interface between the matrix phase and dispersed phase of a composite plays a critical role in influencing its properties. However, the intricate mecha-nisms of interface are not fully understood, and polymer nanocomposites are no exception. This study compares the fabrication, morphology, and mechanical and thermal properties of epoxy nanocomposites tuned by clay layers (denoted as m-clay) and graphene platelets (denoted as m-GP). It was found that a chemical modification, layer expansion and dispersion of filler within the epoxy matrix resulted in an improved interface between the filler mate-rial and epoxy matrix. This was confirmed by Fourier transform infrared spectroscopy and transmission electron microscope. The enhanced interface led to improved mechanical properties (i.e. stiffness modulus, fracture toughness) and higher glass transition temperatures (Tg) compared with neat epoxy. At 4 wt% m-GP, the critical strain energy release rate G1c of neat epoxy improved by 240 % from 179.1 to 608.6 J/m2 and Tg increased from 93.7 to 106.4 �C. In contrast to m-clay, which at 4 wt%, only improved the G1c by 45 % and Tg by 7.1 %. The higher level of improvement offered by m-GP is attributed to the strong interaction of graphene sheets with epoxy because the covalent bonds between the carbon atoms of graphene sheets are much stronger than silicon-based clay

Interaction of a Rectangular Jet with a Flat-Plate Placed Parallel to the Flow

An experimental study is carried out addressing the flowfield and radiated noise from the interaction of a large aspect ratio rectangular jet with a flat plate placed parallel to but away from the direct path of the jet. Sound pressure level spectra exhibit an increase in the noise levels for both the 'reflected' and 'shielded' sides of the plate relative to the free-jet case. Detailed cross-sectional distributions of flowfield properties obtained by hot-wire anemometry are documented for a low subsonic condition. Corresponding mean Mach number distributions obtained by Pitot-probe surveys are presented for high subsonic conditions. In the latter flow regime and for certain relative locations of the plate, a flow resonance accompanied by audible tones is encountered. Under the resonant condition the jet cross-section experiences an 'axis-switching' and flow visualization indicates the presence of an organized 'vortex street'. The trends of the resonant frequency variation with flow parameters exhibit some similarities to, but also marked differences with, corresponding trends of the well-known edgetone phenomenon

Remediation of arsenic from groundwater containing organic compounds by ion exchange media

This research work was dedicated to the problem arising from the coexistence of arsenic and organic substances principally in the US (the Superfund Sites) and Bangladesh. Dissolved organic ions are strong competitors to arsenates, and because of their large size and slow kinetics, arsenic removal becomes problematic. Macroporous ion exchange media can remove both arsenic and organic pollutants efficiently while preserving exchange capacity and effluent quality. The novelty of this work is characterized by the determination of interdependence of important factors influencing the sorption of arsenates and organic substances by macroporous ion exchange media. Exchange capacities of these resins in both chloride and hydroxyl forms in acidic media as well as the chloride-form operating in weakly basic medium were investigated. The investigations were focused on factors such as the effects of pH, influent concentration of dissolved organic matter (DOM) and filtration velocity. Interaction of these effects was also investigated. Reducing the pH from 10.4 to 7.0 increased the arsenate-exchange capacity from 28 meq/kg to 63 meq/kg (a 35 meq/kg increase). Optimum conditions for regeneration of macroporous media have been determined such as a NaCl consumption of 300 kg/tonne, a concentration of NaCl solution of 10%, a ratio of NaCl concentration to that of NaOH in regenerant of 10, a regeneration rate of 4 m/h, and a temperature of 40{493} C. Waste handling processes have been developed to treat and reuse spent regeneration solutions as well as to detoxify the solid waste containing arsenic and organic matter. A reagent based technology for the treatment of spent regeneration solutions by Ca(OH) 2 and MgCl 2 (or MgSO 4 ) has been devised. Based on the results, appropriate decontamination schemes have been developed for groundwater contaminated with arsenic and organic impurities. The benefit of these schemes is guidance for the organization of the treatment process depending upon the levels of mineralization and concentration of DOM as well as the conditions for the implementation of the process (for an existing or new treatment unit to be designed

Possible presence of calcium channel blocker(s) in Rubia cordifolia: An indigenous medicinal plant

Crude extract of Rubia cordifolia (RC) was tested in isolated tissue preparations for its possible calcium channel antagonistic activity. RC suppressed the spontaneous contractions of guinea-pig atria, rabbit jejunum and rat uterus in a concentration dependent manner (0.1-3 mg/ml). In rabbit aorta, it inhibited norepinephrine (10 microM) and KCl (80 mM) induced contractions. Replacement of physiological salt solution with calcium free solution abolished the spontaneous movements of rabbit jejunum. However, addition of calcium (25 micrograms/ml) in the tissue bath restored the spontaneous movements. When the tissues were pretreated with plant extract (1 mg/ml) or verapamil (0.5 microgram/ml), addition of calcium failed to restore spontaneous contractions. These results indicate that the plant extract exhibits spasmolytic activity similar to that of verapamil suggestive of presence of calcium channel blocker like constituent(s) in this plant

268 composition in experimental diabetes

269 alba, Nigella sativa and Trigonella foenum graecum which show the inhibitory effect of glucose utilization, and are in use as hypoglycemic agents of varying degree in traditional system of medicine. The glucose uptake activity of (methanolic extracts) of these plants was tested in vitro and glucose was estimated by glucose oxidase method. The results in three different media revealed that, hypoglycemic activity is more prominent in neutral and basic media as compared to acidic medium