Hypersonic Flight and Ground Testing Activities in India

India has undertaken many hypersonic technology development programmes to meet the goals of future missions in space as well as missile development. While large scale ground based tests facilities are under construction, existing test facilities are being used to develop the preliminary design data needed for flight tests as well as for CFD code validation. A brief review of the hypersonic flight vehicle development programmes and the existing test facilities in the country along with some sample results from our laboratory for these programs is presented here

Noise characteristics of upper surface blown configurations: Analytical Studies

Noise and flow results of upper surface blown configurations were analyzed. The dominant noise source mechanisms were identified from experimental data. From far-field noise data for various geometric and operational parameters, an empirical noise prediction program was developed and evaluated by comparing predicted results with experimental data from other tests. USB aircraft compatibility studies were conducted using the described noise prediction and a cruise performance data base. A final design aircraft was selected and theory was developed for the noise from the trailing edge wake assuming it as a highly sheared layer

Superfluid Phase Stability of 3^3He in Axially Anisotropic Aerogel

Measurements of superfluid $^3$He in 98% aerogel demonstrate the existence of a metastable \emph{A}-like phase and a stable \emph{B}-like phase. It has been suggested that the relative stability of these two phases is controlled by anisotropic quasiparticle scattering in the aerogel. Anisotropic scattering produced by axial compression of the aerogel has been predicted to stabilize the axial state of superfluid $^3$He. To explore this possiblity, we used transverse acoustic impedance to map out the phase diagram of superfluid $^3$He in a $\sim 98$% porous silica aerogel subjected to 17% axial compression. We have previously shown that axial anisotropy in aerogel leads to optical birefringence and that optical cross-polarization studies can be used to characterize such anisotropy. Consequently, we have performed optical cross-polarization experiments to verify the presence and uniformity of the axial anisotropy in our aerogel sample. We find that uniform axial anisotropy introduced by 17% compression does not stabilize the \emph{A}-like phase. We also find an increase in the supercooling of the \emph{A}-like phase at lower pressure, indicating a modification to \emph{B}-like phase nucleation in \emph{globally} anisotropic aerogels.Comment: 4 pages, 4 figures, submitted to LT25 (25th International Conference on Low Temperature Physics

Catalytic non-thermal plasma reactor for the decomposition of a mixture of volatile organic compounds

The decomposition of mixture of selected volatile organic compounds (VOCs) has been studied in a catalytic non-thermal plasma dielectric barrier discharge reactor. The VOCs mixture consisting n-hexane, cyclo-hexane and p-xylene was chosen for the present study. The decomposition characteristics of mixture of VOCs by the DBD reactor with inner electrode modified with metal oxides of Mn and Co was studied. The results indicated that the order of the removal efficiency of VOCs followed as p-xylene > cyclo-hexane > n-hexane. Among the catalytic study, MnOx/SMF (manganese oxide on sintered metal fibres electrode) shows better performance, probably due to the formation of active oxygen species by in situ decomposition of ozone on the catalyst surface. Water vapour further enhanced the performance due to the in situ formation of OH radicals. [Figure not available: see fulltext.

Simulation of the Performance of the IISc Chemical Kinetics Shock Tube

This report presents the results of an investigation of the performance of the Chemical Kinetics Shock tube at the Indian Institute of Science. The one-dimensional Lagrangian code L1d of Jacobs (1998) has been used to simulate the tube at several operating conditions. The conditions have different shock tube filling pressures, resulting in different shock speeds and different tube lengths, resulting in different dwell times. The simulations have been performed both with and without viscous effects simulated in the tubes. At the lowest shock tube filling pressure condition, the shock tube operates in an overtailored mode and it is undertailored at the higher filling pressure conditions. The results show that viscous effects, which lead to attenuation of the primary shock and heat loss from the test gas to the tube walls, result in an increasing p5 pressure during the test time. The viscous effects are more dominant at the condition with the lowest filling pressure (highest primary shock speed). A simulation run for 50 ms after diaphragm rupture or the configuration with a long driver tube shows that the test gas is periodically re-compressed by reflections of waves along the driver and shock tubes. The recompressions become sequentially weaker and thus the test gas temperature and pressure are never raised to as high levels as for the primary compression

Catalytic non-thermal plasma reactor for decomposition of dilute chlorobenzene

Oxidative decomposition of low concentrations of chlorobenzene (CB) in air was carried out in a NTP reactor. Typical results indicated the better performance on addition of metal oxide catalysts in plasma zone. It may be concluded that catalytic plasma approach has promise, especially for the removal of low concentraions of CB, where conventional techniques are not energetically feasible. Among the metal oxides studied, AgOx/MnOx showed the better performance than MnOx and CoOx. During the removal of 50 ppm of CB, AgOx/MnOx under humid conditions showed 100% selectivity to total oxidadtion at 260 J L-1, which may be assigned due to the formation of hydroxyl radical and/or due to in situ ozone decomposition on the catalyst surface that may lead to the formation of a powerful oxidant atomic oxygen. Oxidative decomposition of low concentrations of chlorobenzene in air was carried out in a NTP reactor. Results indicated the improved performance on addition of catalysts in plasma zone. It has been observed that the integration of metal oxides, promoted the total oxidation, whose activity was further enhanced on addition of water vapor. During the abatement of 50 ppm of CB, selectivity to CO2 was 100% at 260 J L-1 with AgOx/MnOx/SMF catalytic electrode

PPARα: energy combustion, hypolipidemia, inflammation and cancer

The peroxisome proliferator-activated receptor α (PPARα, or NR1C1) is a nuclear hormone receptor activated by a structurally diverse array of synthetic chemicals known as peroxisome proliferators. Endogenous activation of PPARα in liver has also been observed in certain gene knockout mouse models of lipid metabolism, implying the existence of enzymes that either generate (synthesize) or degrade endogenous PPARα agonists. For example, substrates involved in fatty acid oxidation can function as PPARα ligands. PPARα serves as a xenobiotic and lipid sensor to regulate energy combustion, hepatic steatosis, lipoprotein synthesis, inflammation and liver cancer. Mainly, PPARα modulates the activities of all three fatty acid oxidation systems, namely mitochondrial and peroxisomal β-oxidation and microsomal ω-oxidation, and thus plays a key role in energy expenditure. Sustained activation of PPARα by either exogenous or endogenous agonists leads to the development of hepatocellular carcinoma resulting from sustained oxidative and possibly endoplasmic reticulum stress and liver cell proliferation. PPARα requires transcription coactivator PPAR-binding protein (PBP)/mediator subunit 1(MED1) for its transcriptional activity