Effect of Sweptback Angle of a Delta Wing on Surface Pressure Distribution at Supersonic Mach Numbers

The purpose of this work is to shed light on the effect of the pivot position on the surface pressure distribution over a 3D wing in different flight conditions.The study is intended to support the design and development of aerospace vehicles where stability analysis,performance optimization,and aircraft design are of primary importance.The following parameters are considered:Mach numbers(M)of 1.3,1.8,2.3,2.8,3.3,and 3.8,angle of incidence(θ)in the range from 5°to 25°,pivot position from h=0.2 to 1.The results of the CFD numerical simulations match available analytical data,thereby providing evidence for the reliability of the used approach.The findings provide valuable insights into the relationship between the surface pressure distribution,the Mach number and the angle of incidence.

Crystal and Molecular Structure of Ethyl 2-[(4-Hydroxy-phenyl)hydrazono]-3-oxobutanoate

The title compound,C 12 N 2 O 4 H 14 （M r=250.3）,crystallizes in triclinic P1 space group with a=7.7709（9）,b=8.7534（11）,c=9.6958（12）,α=77.103（2）,β=80.496（2）,γ=86.726（2）o,V=633.9（1） 3,Z=2,F（000）=264,D c=1.311 Mg/m 3,μ（MoKα）=0.1 mm-1,the final R=0.056,and wR=0.15 for 2239 observed reflections （I 2σ（Ⅰ））.The molecules in the crystal are linked through O-H···O type of hydrogen bonding interaction forming an infinite chainlike structure.The phenylhydrazone ring and oxobutanoate groups are almost planar.The keto hydrazo group adopts a Z-configuration in the molecule and the torsion angle is-177.6（2）°.

Design of Reduced Graphene Oxide Based Piezo-Resistive Type Acoustic Sensor on Flexible Kapton for Underwater Applications

Micro Electro Mechanical Systems (MEMS) vector sensor is a recent advancement in the field of underwater acoustic sensors. The major incentive provided by this acoustic vector sensor is that it provides information about the direction of the incoming acoustic source signal in addition to the measurement of the pressure associated with the acoustic signal. We are reporting a design of a MEMS acoustic vector sensor for underwater applications using piezoresistive film of Reduced Graphine Oxide (RGO), realized on kapton (polyimide) film as the starting material. The sensor is designed and fabricated by deposition of RGO on a kapton, which is a flexible substrate by the method of drop casting making the process simple, low-cost and scalable. The application of the piezoresistive transduction principle and ingenious structure of the vector sensor based on bionic principle improves miniaturization and the low-frequency sensitivity. The fabricated sensor shows a repeatable response in both static and dynamic conditions, to the applied strain due to the acoustic signal in a given direction. The experimental results show that fabricated sensor based on MEMS technology and piezoresistive effect is feasible and it possesses intrinsic two-dimensional directivity. The fabricated device has given good response for the low-frequency acoustic signals due to the effect of piezoresistive transduction principle and the resonance frequency of the device is found to be around 80 Hz with the displacement sensitivity around 3 mV/mm and 2 mV/mm of X and Y axis directions respectively.

Fatigue Behaviour of Silicon Carbide and Fly Ash Dispersion Strengthened High Performance Hybrid Al 5083 Metal Matrix Composites

Fatigue is a major issue concerning the use of aluminium composites in structural applications. Fatigue leads to weakening of material majorly due to the strain bands formed in the material when it is subjected to repeated loading;the damage that occurs due to fatigue is a progressive and localized one. The fatigue may occur at a stress limit much lesser than the ultimate stress limit of the composite specimen. Henceforth in the current work, fatigue behaviour of silicon carbide and fly ash dispersion strengthened high performance hybrid Al 5083 metal matrix composites are evaluated. The main purpose of fatigue characterisation is to distinctly evaluate the life cycle of components that are fabricated from metal matrix composites and eventually develop a framework model for the significant study of fatigue strength of the structure with persistent striations all along the interstitials of aluminium- silicon carbide-fly ash interfaces. Fatigue is a stochastic process rather than a deterministic one that gives a considerable scatter, even among samples of similar composition with the tests carried out in some of the critically controlled environments. Hence there is a need for statistical validation of the results to authenticate the data collected. Thus in the current work, analysis of variance is carried out to establish the authenticity of the results and validate them. The results and plots are presented with suitable rationale and inferences.