Effect of Formability Process Parameters in Dynamic Strain Ageing Region ofAustenitic Stainless Steel

The consumption of Austenitic Stainless-Steel ASS 304 has been increasing recently in the outer body of Automobileapplications. Sheet Metal Forming is one of the processes used to convert ASS 304 sheet into an end product. ASS 304 hasgood ductility with the rise in temperature up to 450oC and later dynamic strain aging (DSA) in the temperature range 450-600oC. Formability studies of ASS 304 in the DSA region and the effect of process parameters like anisotropy and strainrate are investigated in the present paper. Stretch forming Investigations have been carried out at a temperature of 500oC intwo quasi-static strain rate ranges 1x 10-4 s-1 and 1x 10-1 s-1 concerning three orientations parallel (R0), diagonal (R45) andTransverse(R90) to Rolling Direction. The experiments were carried out at both the necking and fracture regions. Deformedspecimens' major and minor strains are measured to plot Fracture Forming limit Diagrams, strain distribution, and limitingDome height. Particular attention is given to the evaluation of strain rate and orientation of the sheet concerning rollingdirection on formability

Jointly trained image and video generation using residual vectors

In this work, we propose a modeling technique for jointly training image and video generation models by simultaneously learning to map latent variables with a fixed prior onto real images and interpolate over images to generate videos. The proposed approach models the variations in representations using residual vectors encoding the change at each time step over a summary vector for the entire video. We utilize the technique to jointly train an image generation model with a fixed prior along with a video generation model lacking constraints such as disentanglement. The joint training enables the image generator to exploit temporal information while the video generation model learns to flexibly share information across frames. Moreover, experimental results verify our approach's compatibility with pre-training on videos or images and training on datasets containing a mixture of both. A comprehensive set of quantitative and qualitative evaluations reveal the improvements in sample quality and diversity over both video generation and image generation baselines. We further demonstrate the technique's capabilities of exploiting similarity in features across frames by applying it to a model based on decomposing the video into motion and content. The proposed model allows minor variations in content across frames while maintaining the temporal dependence through latent vectors encoding the pose or motion features.Comment: Accepted in 2020 Winter Conference on Applications of Computer Vision (WACV '20

Mechanical and Microstructural Evolution of Friction stir welded joint of AA2014 alloys

The solidification cracking phenomenon restricts the use of fusion welding process to join aluminum and its alloy. Friction stir welding (FSW) process can be used in joining of aluminium alloys which is not or less susceptible to form welded voids, induced distortions, solidification cracking. In the present work an investigation of mechanical and microstructural changes after FSW is presented during the similar joining of AA2014 aluminium alloys. The influences of tool geometry during FSW is analysed and compared among the joint made by triangular, pedal and pentagonal pin. Based on the obtained mechanical properties of the joint metallurgical investigation is performed. Optical micrographs are used to reveal the phases present in the fusion zone. EBSD investigation of the selected sample is done to analyse the mis-orientaion angle and grain size etc. Pedal pin profile tool exhibit better mechanical properties in comparison to pentagonal pin and triangular pin. Obtained ultimate tensile strength and percentage elongation are 345MPa and 13.5 % respectively. Micro-hardness and impact energy are obtained as 125HV0.2 and 4.6 J of Fpedal sample. Obtained joint efficiency of Fpedal sample is 74%, which is higher among joint efficiency of Fpentagonal and Ftringular samples

Daksha: On Alert for High Energy Transients

We present Daksha, a proposed high energy transients mission for the study of electromagnetic counterparts of gravitational wave sources, and gamma ray bursts. Daksha will comprise of two satellites in low earth equatorial orbits, on opposite sides of earth. Each satellite will carry three types of detectors to cover the entire sky in an energy range from 1 keV to >1 MeV. Any transients detected on-board will be announced publicly within minutes of discovery. All photon data will be downloaded in ground station passes to obtain source positions, spectra, and light curves. In addition, Daksha will address a wide range of science cases including monitoring X-ray pulsars, studies of magnetars, solar flares, searches for fast radio burst counterparts, routine monitoring of bright persistent high energy sources, terrestrial gamma-ray flashes, and probing primordial black hole abundances through lensing. In this paper, we discuss the technical capabilities of Daksha, while the detailed science case is discussed in a separate paper.Comment: 9 pages, 3 figures, 1 table. Additional information about the mission is available at https://www.dakshasat.in

Science with the Daksha High Energy Transients Mission

We present the science case for the proposed Daksha high energy transients mission. Daksha will comprise of two satellites covering the entire sky from 1~keV to $>1$~MeV. The primary objectives of the mission are to discover and characterize electromagnetic counterparts to gravitational wave source; and to study Gamma Ray Bursts (GRBs). Daksha is a versatile all-sky monitor that can address a wide variety of science cases. With its broadband spectral response, high sensitivity, and continuous all-sky coverage, it will discover fainter and rarer sources than any other existing or proposed mission. Daksha can make key strides in GRB research with polarization studies, prompt soft spectroscopy, and fine time-resolved spectral studies. Daksha will provide continuous monitoring of X-ray pulsars. It will detect magnetar outbursts and high energy counterparts to Fast Radio Bursts. Using Earth occultation to measure source fluxes, the two satellites together will obtain daily flux measurements of bright hard X-ray sources including active galactic nuclei, X-ray binaries, and slow transients like Novae. Correlation studies between the two satellites can be used to probe primordial black holes through lensing. Daksha will have a set of detectors continuously pointing towards the Sun, providing excellent hard X-ray monitoring data. Closer to home, the high sensitivity and time resolution of Daksha can be leveraged for the characterization of Terrestrial Gamma-ray Flashes.Comment: 19 pages, 7 figures. Submitted to ApJ. More details about the mission at https://www.dakshasat.in

Metamaterial Based Multiple Frequency Antenna

Abstract: Antennas that are electrically small, efficient and have significant bandwidth would fill many needs of new generation communications systems if antenna engineers could reconcile these usually contradictory requirements. The introduction of the so-called metamaterials (MTMs), artificial materials which have engineered electromagnetic responses that are not readily available in nature, has provided an alternate design approach to obtain efficient electrically-small antenna (EESA)systems. A micro strip antenna based on metamaterial is proposed in this paper. The purpose of this work is to investigate the response of a small antenna enclosed in metamaterial. The new structure is useful in designing small antennas. Return loss less than-50 dB has been achieved at 2.426 GHz. Antenna also radiates at 1.24 GHz, 2.51 GHz and 2.95GHz effectively

Jointly trained image and video generation using residual vectors

In this work, we propose a modeling technique for jointly training image and video generation models by simultaneously learning to map latent variables with a fixed prior onto real images and interpolate over images to generate videos. The proposed approach models the variations in representations using residual vectors encoding the change at each time step over a summary vector for the entire video. We utilize the technique to jointly train an image generation model with a fixed prior along with a video generation model lacking constraints such as disentanglement. The joint training enables the image generator to exploit temporal information while the video generation model learns to flexibly share information across frames. Moreover, experimental results verify our approach's compatibility with pre-training on videos or images and training on datasets containing a mixture of both. A comprehensive set of quantitative and qualitative evaluations reveal the improvements in sample quality and diversity over both video generation and image generation baselines. We further demonstrate the technique's capabilities of exploiting similarity in features across frames by applying it to a model based on decomposing the video into motion and content. The proposed model allows minor variations in content across frames while maintaining the temporal dependence through latent vectors encoding the pose or motion features.</p

Secured Network on Chip (NoC) Architecture and Routing with Modified TACIT Cryptographic Technique

AbstractNetwork on Chip (NoC) architecture needed secured data processing and routing in multicore system on Chip (SoC). Sometime it becomes very difficult to provide secured network routing for physically access network. The performance of NoC architecture depends on switching techniques, routing scheme and topological structure. The paper proposed the chip implementation of the new technique of securing data in NoC routers. Many algorithms have been anticipated already for secured NoC routing but limited to their key size and block size. In the paper, NoC architecture is integrated with modified TACIT security algorithm on Virtex-5 FPGA. The key generation scheme is considered based on Hash function and distributed under 4 Hash function (4H) scheme. The greatest advantage of TACIT security algorithm is that the block size and key size both can be of ‘n’ bit. The design is developed for ‘n’ bit with the help of VHDL programming language in Xilinx ISE 14.2 and Modelsim 10.1 b software and synthesized for 512 and 1024 bit of block size on Virtex-5 FPGA. The design is optimized with the help of device utilization summary, timing parameters, maximum frequency and memory support

Effect of Formability Process Parameters in Dynamic Strain Ageing Region of Austenitic Stainless Steel

809-816The consumption of Austenitic Stainless-Steel ASS 304 has been increasing recently in the outer body of Automobile applications. Sheet Metal Forming is one of the processes used to convert ASS 304 sheet into an end product. ASS 304 has good ductility with the rise in temperature up to 450oC and later dynamic strain aging (DSA) in the temperature range 450- 600oC. Formability studies of ASS 304 in the DSA region and the effect of process parameters like anisotropy and strain rate are investigated in the present paper. Stretch forming Investigations have been carried out at a temperature of 500oC in two quasi-static strain rate ranges 1x 10-4 s-1 and 1x 10-1 s-1 concerning three orientations parallel (R0), diagonal (R45) and Transverse(R90) to Rolling Direction. The experiments were carried out at both the necking and fracture regions. Deformed specimens' major and minor strains are measured to plot Fracture Forming limit Diagrams, strain distribution, and limiting Dome height. Particular attention is given to the evaluation of strain rate and orientation of the sheet concerning rolling direction on formability