CryptoCT: towards privacy preserving color transfer and storage over cloud

Multimedia Tools and Applications - Current trend toward cloud computing coupled with emerging technologies such as high definition images/videos and 360-degree videos, has led the requirement of...     

Effect of three-dimensional melt pool convection on process characteristics during laser cladding

A three-dimensional heat transfer model is developed to simulate the cladding process that include the different physical phenomena such as heat transfer, phase changes, addition of powder particles and fluid flow due to Marangoni–Rayleigh–Benard convection. It is found that the Rayleigh–Benard convection is insignificant and Marangoni–Benard convection is dominant for the studied cases. By varying the scanning speed and Marangoni number the melt pool size and strength of convection are changed and its influence on clad built-up geometry, dilution level, maximum and average melt pool temperatures and the form and scale of the microstructure of the solidified clad track has been studied.     

Hybrid Resource Allocation Scheme in Multi-hop Device-to-Device Communication for 5G Networks

Wireless Personal Communications - The 5G communication paradigm provides architecture of coexistence of device-to-device (D2D) communication with the current cellular communication. Direct D2D...     

Effect of thermal conditioning on the initiation threshold of secondary high-explosives

While most performance metrics of high-explosive (HE) based devices like detonation velocity, detonation pressure, and energy output are expected to degrade over time, the evolution of initiation threshold appears less clear, with claims of both increasing and decreasing trends in threshold having been made in the literature. This work analyzes D-optimally designed sequential binary test data for a few thermally conditioned porous-powder and polymer-bonded HE initiator systems using a Bayesian likelihood method employing the probit regression model. We find that in most cases the initiation threshold decreases (i. e., sensitivity increases) upon accelerated thermal conditioning. However, such results are nuanced and influenced by factors like the contact area of initiating stimulus, HE characteristics like density and specific surface area, as well as possible thermally induced changes to other materials and interfaces involved.     

Modeling Growth,Surface Kinetics,and Morphology Evolution in PETN

Pentaerythritol tetranitrate (PETN) is a commonly used energetic material with both military and civilian applications. Good ignition properties mandate a powdered material with a high surface area. However, existing experimental data on PETN powder suggest an active surface that leads to particle coarsening and gradual reduction of the specific surface area over time. In this work we review some of the atomic‐level and coarse‐grained potential models developed for PETN and discuss their applications for studying particle morphology, growth, and surface kinetics, including molecular diffusion and evaporation/condensation rates. Simulation methods include classical molecular dynamics, kinetic Monte Carlo, and transition state calculations.     

Investigation and Development of 3D Printed Conventional Shape Compact UWB-DRAs for Societal Applications

Wireless Personal Communications - The potential of polylactic acid (PLA) material as an ultra-wide band (UWB)-dielectric resonator antenna (DRA) created by 3D-printing technique are described in...     

A mesoscopic network model for permanent set in crosslinked elastomers

A mesoscopic computational model for polymer networks and composites is developed as a very coarse-grained representation of the network microstructure. Unlike more complex molecular dynamics simulations, the model network is static unless undergoing deformation. The elastic modulus, which depends only on the crosslink density and parameters in the bond potential, is consistent with rubber elasticity theory, and the network response satisfies the independent network hypothesis of Tobolsky. The model, when applied to a commercial filled silicone elastomer, quantitatively reproduces the experimental permanent set and stress-strain response due to changes in the crosslinked network from irradiation.     

Simulation of Cooling of Double-Layered Splat and its Experimental Validation Using Jackson–Hunt Theory

A model of heat transfer and fluid flow during the sequential impingement of two liquid Al-33 wt pct Cu droplets on a 304 stainless steel substrate has been developed on the FLUENT 6.3.16 platform. The model was validated using the Jackson–Hunt theory (K.A. Jackson and J.D. Hunt: Trans. Metall. Soc. AIME, 1966, vol. 236, pp. 1129–42). During the impingement of the second droplet on the first splat, transient air gap formation and remelting of solidified region of the first splat occurred.     

PETN Coarsening – Predictions from Accelerated Aging Data

Ensuring good ignition properties over long periods of time necessitates maintaining a good level of flow porosity in powders of initiator materials and preventing particle coarsening. To simulate flow porosity changes of such powder materials over long periods of time a common strategy is to perform accelerated aging experiments over shorter time spans at elevated temperatures. In this paper, we examine historical accelerated‐aging data on powders of pentaerythritol tetranitrate, an important energetic material, and make predictions for long‐term aging under ambient conditions. We develop an evaporation–condensation‐based model to provide some mechanistic understanding of the coarsening process.     

Multiscale modeling with carbon nanotubes

Technologically important nanomaterials come in all shapes and sizes. They can range from small molecules to complex composites and mixtures. Depending upon the spatial dimensions of the system and properties under investigation computer modeling of such materials can range from equilibrium and non-equilibrium quantum mechanics, to force-field-based molecular mechanics and kinetic Monte Carlo, mesoscale simulation of evolving morphology, and finite-element computation of physical properties. This brief review illustrates some of the above modeling techniques through a number of recent applications with carbon nanotubes: nano electromechanical sensors (NEMS), chemical sensors, metal-nanotube contacts, and polymer-nanotube composites.