Design and Development of an Airblast Atomiser for the KAVERI engine and the sectoral combustor tests

This report deals with the design and development of an airblast atomiser for application in the KAVERI engine. Five atomisers of the chosen design were fabricated and tested at ambient conditions to determine the fuel spray SMD, patternation, cone angle and atomiser flow number. The atomiser performance parameters specified were achieved and hot tests carried out in the 90° combustor sector. The combustor pressure loss, exit temperature distribution, ignition and stability limits were evaluate

Leptonic decay of Heavy-light Mesons in a QCD Potential Model

We study the masses and decay constants of heavy-light flavour mesons D, Ds, B and Bs in a QCD Potential model. The mesonic wavefunction is used to compute the masses of D and B mesons in the ground state and the wavefunction is transformed to momentum space to estimate the pseudoscalar decay constants of these mesons. The leptonic decay widths and branching ratio of these mesons for different leptonic channels are also computed to compare with the experimental values. The results are found to be compatible with available data.Comment: 9 pages,3 table

A Method for Dynamic Characterization and Response Prediction Using Ground Vibration Test(GVT)Data for Unknown Structures.

The Objective Of This Proposed Work Is To Develop A Reliable Method For Dynamic Characterization And Prediction Of Dynamic Response Of Structures Of Known/Unknown Configurations, By Processing The Free Vibration Data Generated Experimentally From The Ground Vibration Tests (GVT)Of The Prototype Vehicles. The Methodology Would Make Use Of The Measured Dynamic Data In Terms Of Mode Shapes, Natural Frequencies, Modal Damping, Point Impedances Etc.And Generate Modal (Scaled) Stiffness And Inertia Information That Will Be Used For Prediction Of Response Characteristics Of The Prototype Structure . With These Objectives, The Present Work Develops The Mathematical Formulation Of The Method, And Demonstrates Its Reliability By Performing The Experiment On A Simple Cantilever Beam To Determine Its Dynamic Characteristics. Results On Scaled Modal Stiffness And Inertia, Generated Through The Method Using Experimental (GVT) Data Show Excellent Agreement With Those Generated By FE And Analytical Models .It Must Be Noted That A Valid Benchmarking Is Performed With The Condition That The Experimental Procedure Is 'Blind' To The Actual Stiffness And Inertia Distributions As Used In FEM Or Analytical Models . Agreement Of The Predicted Response Of The Structure With That From Direct Experiment And Those From The FE And Analytical Models Indicates That This Method Will Be A Promising Tool To Predict The Dynamic And Aeroelastic Characteristics Of Any Prototype Vehicle In The Future. Once The Reliability Of The Method Is Established,It Can Be Extended To Determine The Dynamic And Aeroelastic Characteristics Of All Aircraft For Which Dynamic Characteristics Are Available From A Ground -; Vibration Test (GVT)

Effect of tool pin diameters on friction stir welding of Aluminium alloy 5083

Friction stir welding is a solid-state welding process invented by the welding institute (TWI) of UK in 1991. The main objective is to study the effect of rotational speed and tool pin diameters of straight cylindrical tool on mechanical properties of Aluminium Alloy5083. Three different tool pin diameters (2.5mm,4mm,6mm) have been used to fabricate the joints at three different tool rotational speeds (710,1120 and 1400rpm) by keeping the constant welding speed and axial force. Tensile properties and micro hardness of the joints have been evaluated

Was the Cosmic Web of Protogalactic Material Permeated by Lobes of Radio Galaxies During the Quasar Era?

Evidence for extended active lifetimes (> 10^8 yr) for radio galaxies implies that many large radio lobes were produced during the `quasar era', 1.5 < z < 3, when the comoving density of radio sources was 2 -- 3 dex higher than the present level. However, inverse Compton losses against the intense microwave background substantially reduce the ages and numbers of sources that are detected in flux-limited surveys. The realization that the galaxy forming material in those epochs was concentrated in filaments occupying a small fraction of the total volume then leads to the conclusion that radio lobes permeated much of the volume occupied by the protogalactic material during that era. The sustained overpressure in these extended lobes is likely to have played an important role in triggering the high inferred rate of galaxy formation at z > 1.5 and in the magnetization of the cosmic network of filaments.Comment: 5 pages, 0 figures, submitted to ApJ Letters; uses emulateapj