An experimental study of near wall flow parameters in the blade end-wall corner region

The near wall flow parameters in the blade end-wall corner region is investigated. The blade end-wall corner region was simulated by mounting an airfoil section (NACA 65-015 base profile) symmetric blades on both sides of the flat plate with semi-circular leading edge. The initial 7 cm from the leading edge of the flat plate was roughened by gluing No. 4 floor sanding paper to artificially increase the boundary layer thickness on the flat plate. The initial flow conditions of the boundary layer upstream of the corner region are expected to dictate the behavior of flow inside the corner region. Therefore, an experimental investigation was extended to study the combined effect of initial roughness and increased level of free stream turbulence on the development of a 2-D turbulent boundary layer in the absence of the blade. The measurement techniques employed in the present investigation included, the conventional pitot and pitot-static probes, wall taps, the Preston tube, piezoresistive transducer and the normal sensor hot-wire probe. The pitot and pitot-static probes were used to obtain mean velocity profile measurements within the boundary layer. The measurements of mean surface static pressure were obtained with the surface static tube and the conventional wall tap method. The wall shear vector measurements were made with a specially constructed Preston tube. The flush mounted piezoresistive type pressure transducer were employed to measure the wall pressure fluctuation field. The velocity fluctuation measurements, used in obtaining the wall pressure-velocity correlation data, were made with normal single sensor hot-wire probe. At different streamwise stations, in the blade end-wall corner region, the mean values of surface static pressure varied more on the end-wall surface in the corner region were mainly caused by the changes in the curvature of the streamlines. The magnitude of the wall shear stress in the blade end-wall corner region increased significantly in the close vicinity of the corner line. The maximum value of the wall shear stress and its location from the corner line, on both the surfaces forming the corner region, were observed to change along the corner. These observed changes in the maximum values of the wall shear stress and its location from the corner line could be associated with the stretching and attenuation of the horseshoe vortex. The wall shear stress vectors in the blade end-wall corner region were observed to be more skewed on the end-wall surface as compared to that on the blade surface. The differences in the wall shear stress directions obtained with the Preston tube and flow visualization method were within the range in which the Preston tube was found to be insensitive to the yaw angle

Dispersion of Cytotoxic Properties of Multi-Walled Carbon Nanotubes Suspended in Biological Solutions with Tween 80: Their Role in Enhancing Killing Effects of Nanosecond Pulse Electric Fields on Tumor Cell Lines

The objective of this study was to determine whether multi-walled carbon nanotubes (MWCNTs) suspended in the surfactant Tween 80 give an additive killing effect on tumor cells when exposed to nsPEFs. In this study, MWCNTs were suspended in DMEM and RPMI with or without T80 (surfactant). The size distribution of MWCNTs suspended in these solutions was evaluated with a Delsa™ Nano Zeta potential and sub micro particle Size Analyzer and confirmed with microscopy. The cytotoxicity of MWCNTs dispersed in different concentrations of T80 was evaluated in PANC1 (Human pancreatic cancer cell line) and Jurkat cell lines (Human T-cell lymphoblast cell line). Results showed that Tween 80 played a significant role in the dispersion of MWCNTs in DMEM and RPMI. Results also indicated that there was no significant difference in the dispersion ability in DMEM versus RPMI. Microscopic analysis indicated that MWCNTs formed uniform and well-dispersed suspensions in the presence of Tween 80. Cytotoxicity results showed that the optimum concentration of Tween 80 required to suspend MWCNTs without limiting dispersion properties is 0.2%. Although PANC1 and Jurkat cell lines showed toxicity in the presence of MWCNTs, the concentration of MWCNTs toxic to PANCI and Jurkat cells was different (50 μg/ml in Jurkat cells and 100 μg/ml in PANC1 cells) NsPEFs are ultra short electric pulses that have the ability to kill tumor cells. PANC1 and Jurkat cells were exposed to nsPEFs in the presence of MWCNTs suspended in 0.2% T80, 0.2% T80 (alone) and compared to exposure in cell culture media (DMEM and RPMI). Results suggest that high concentration of MWCNTs give a strong background in WST-1 cell viability assay and therefore, it is concluded that WST-1 cell viability assay is not suitable to measure cell viability in the presence of MWCNTs. Cell viability results after exposure to nsPEFs elucidates the significant effect of 0.2% Tween 80 in enhancing the killing effect of nsPEFs; in contrast, MWCNTs at the tested concentrations did not have any significant effect on enhancing the killing effects of nsPEFs. Therefore, Tween 80 plays a significant role as good dispersant of MWCNTs and as a potential adjuvant (for example in drug delivery) for nsPEFs in killing tumor cells

Ion Adsorption Properties of Molybdenum Ferrocyanide, Tungsten Ferrocyanide & Multiloaded Molybdenum Ferrocyanide- Dowex Exchangers

800-80

Extra-judicial killings in India: a crisis of justice, faith and public morality?

This post discusses extrajudicial killings in India, the consequent legal challenges they create, and the increasing normalisation of such encounters through pop culture and public acclamation. Gauri Kumar and Naina Bhargava highlight these arguments using specific examples, and present the existing response of the Supreme Court of India regarding extrajudicial killings

A stable mode of bookmarking by TBP recruits RNA polymerase II to mitotic chromosomes.

Maintenance of transcription programs is challenged during mitosis when chromatin becomes condensed and transcription is silenced. How do the daughter cells re-establish the original transcription program? Here, we report that the TATA-binding protein (TBP), a key component of the core transcriptional machinery, remains bound globally to active promoters in mouse embryonic stem cells during mitosis. Using live-cell single-molecule imaging, we observed that TBP mitotic binding is highly stable, with an average residence time of minutes, in stark contrast to typical TFs with residence times of seconds. To test the functional effect of mitotic TBP binding, we used a drug-inducible degron system and found that TBP promotes the association of RNA Polymerase II with mitotic chromosomes, and facilitates transcriptional reactivation following mitosis. These results suggest that the core transcriptional machinery promotes efficient transcription maintenance globally