Heritage Institute of Technology

About: Heritage Institute of Technology is a based out in . It is known for research contribution in the topics: Support vector machine & Transconductance. The organization has 581 authors who have published 1045 publications receiving 8345 citations.

Modeling Dynamic Stability and Cutting Forces in Micro Milling of Ti6Al4V Using Intermittent Oblique Cutting Finite Element Method Simulation-Based Force Coefficients

Abstract: Tool breakage is a significant issue in micro milling owing to the less stiffness of the micro tool. To cope up with such limitation, precise predictions of dynamic stability, and cutting force have the utmost importance to monitor and optimize the process. In this article, dynamic stability and cutting force are predicted precisely for micro milling of Ti6Al4V by obtaining force coefficients from a novel 3D intermittent oblique cutting finite element method (FEM) simulation considering the influence of tool run out. First, the stability model is modified by incorporating the appropriate values of limiting angles obtained analytically accounting the trajectories of the flutes due to tool run out. This stability model is utilized to select chatter-free parametric combinations for micro milling tests. Next, an improved cutting force model is developed by incorporating the force coefficients obtained from oblique cutting simulation in the mechanistic model and differentiating the whole machining region into three distinct region considering size effect. The force model also considers the effect of increased edge radius of the worn tool, run out, elastic recovery, ploughing, minimum undeformed chip thickness (MUCT), and limiting angles, cumulatively. The proposed dynamic stability and cutting force models based on the oblique cutting simulation show their adequacy by predicting the stability limit and cutting force more precisely, respectively, as compared to those obtained by orthogonal cutting simulation. Besides, the proposed force model for the worn tool is found to be viable as it is closer to the experimental forces, whereas force model without the incorporation of tool wear underestimated the experimental forces.

Random selection based GA optimization in 2D-DCT domain color image steganography

Abstract: Steganography, the hiding technique used to secure sensitive data (i.e., images, audio ) while communication takes place. In this paper, the message is embedded in color image in frequency domain exploiting Genetic Algorithm (GA) which provides the robustness i.e., the algorithm can withstand against any rigorous testing and brutal attack except destruction of the stego image. The fragmentation of 8-bit binary stream of each color component to 4-bit and applying Genetic Algorithm (GA) to increase the robustness of the scheme. Random Multiple bits are chosen to embed secret message which increases security along with the payload. The use of transform domain, hash function based random pixel and bit selections for data hiding, secrete data encryption and more over use of Genetic Algorithm (GA) for optimization is the novelty of the proposed work. Perspective and meticulous statistical analysis has been done to immune the algorithm from any attack. The algorithm proposed here is tested with benchmark tools like StirMark 4.0, Confusion Matrix (Receiver Operating Curve Characteristic (ROC) curve) along with steganalysis and statistical tools. Visual disturbance and distortion in stego image is also very insignificant here.

Corrosion protection of reinforcement steel rebars by the application of electroless nickel coatings

Abstract: Pitting corrosion and susceptibility to chloride attacks are the shortfalls of reinforcement steel used in concrete structures. The present work proposes the deposition of electroless nickel coatings to provide barrier protection due to their proven corrosion resistance. The effect of deposition of Ni-P, Ni-P-W and Ni-P-Cu coatings on the corrosion behavior of Fe ? 600 grade rebars in 3.5% NaCl has been investigated with the aid of potentiodynamic polarization and electrochemical impedance spectroscopy. The corrosion potential of bare rebar was observed to be -653 mV while that of electroless Ni-P, Ni-P-W and Ni-P-Cu coatings was -436, -391 and -356 mV respectively. The corrosion current density of the rebars also decreased significantly by the application of electroless nickel coatings. Nyquist plots also revealed a bigger semicircular loop for the coated rebars. The chloride attack was severe on the bare uncoated rebar and scanning electron micrograph revealed severe cracking. On the other hand, the vulnerability of the electroless coated rebars to pitting corrosion decreased greatly.

Design of end-on cyanato bridged trinuclear Cu(II) Schiff base complex with salen type Schiff base ligand: synthesis, structural investigation and DFT study

Abstract: One ONNO-donor tetradentate Schiff base ligand LH2 was derived from the condensation of salicylaldehyde and 1,3-diaminopropane and reacted with Cu(NO3)2·6H2O and NaNCO to yield one trinuclear complex with molecular formula [Cu3L2(µ1,1-NCO)2]. The synthesized complex was characterized by IR, UV–vis spectroscopy, and electrochemical analysis. Single-crystal X-ray diffraction study explores that the two terminal copper atoms adopt square pyramidal geometry, whereas the central copper atom situated at the inversion center is surrounded by four phenoxo oxygens and two end-on cyanato anions to adopt an octahedral geometry. The ONNO-tetradentate Schiff base ligand coordinates with the copper(II) ion via two oxygen atoms of the phenoxo-group and two nitrogen atoms from the imine moiety. A theoretical density functional theory (DFT) calculation was also carried out to supplement the experimental results. All the DFT calculations were done in gas phase.