Free radical polymerization of ethyl methacrylate and ethyl α-hydroxy methacrylate: A computational approach to the propagation kinetics

The propagation kinetics of ethyl methacrylate (EMA) and ethyl α-hydroxy methacrylate (EHMA) has been subject to a computational study to understand their free radical polymerization (FRP) behavior in bulk and in solution using Density Functional Theory (DFT). The propagation of EHMA is studied in ethanol and toluene to assess the effect of hydrogen-bonding solvents on FRP of monomers with α-hydroxy functionality. Although EMA and EHMA resemble each other in structure, EHMA propagates faster in bulk due to the presence of intermolecular hydrogen-bonds, which tend to facilitate the approach of the propagating species. This falls in contrast with the experimentally observed lower propagation rates of EHMA in ethanol compared to toluene. Calculations show that the 2.28 rate acceleration in toluene is governed by the ratio of the pre-exponential factors, which reflect the entropies of activation, in both media. The polar protic solvent ethanol has a disruptive effect via hydrogen-bonding on the 6-membered ring shape of EHMA monomers thus decreasing the entropy of activation of the reaction. In the case of toluene, there are no special interactions with the hydrophobic solvent, the entropy of activation is higher than in ethanol.     

Population balance modelling of protein precipitates exhibiting turbulent flow through a circular pipe

The breakage of liquid-liquid, solid-liquid and solid-gas dispersions occurs in many industrial processes during the transport of particulate materials. In this work, breakage of whey protein precipitates passing through a capillary pipe is examined and an experimentally derived breakage frequency is applied to construct a suitable population balance model to characterize the breakage process. It has been shown that the breakage frequency of precipitate particles is highly dependent on their shear history and on the turbulent energy dissipation rate in the pipe. The population balance equation (PBE) uses a volume density based discrete method which is adapted from mass density based discretization. In addition to comparing the model with experimental data, predicted results at different velocities are presented. It was found that the population balance breakage model provides satisfactory results in terms of predicting particle size distributions for such processes.     

Application of Markov chains on image enhancement

Stochastic image processing tools have been widely used in digital image processing in order to improve the quality of the images. Markov process is one of the well-known mathematical modeling tools in stochastic theory. In this study, a Markov chain model has been developed and applied to image denoising. The transition probabilities were obtained from Fokker–Planck diffusion equation. According to the results, the proposed Markov chain model supplies very good peak signal to noise ratio values along with low computational cost.     

Mathematical modelling of a solid particle motion in a re‐circulatory fluidised bed unit

Two fundamental properties of the particles are their velocity and consequent displacement versus time history during the granulation process. Knowledge of the particle velocity might supply much information about the sub‐processes. In this paper, an analytical model of a solid particle motion in an internal re‐circulatory fluidised bed unit is developed and validated against experimentally obtained data. The model predictions show good correspondence with the experimental results for the spherical particles. For the case of non‐spherical granules, the agreement between the model and the experiments is not equally convincing but still adequate.     

A probabilistic object tracking model based on condensation algorithm

Object tracking, which has many application in our daily life, is an important topic in electronics engineering area. It basically deals with estimation and location of an object in given video frames. In this paper, a novel object tracking algorithm based on particle filtering associate with population balances is proposed. The developed algorithm was used to track objects in synthetic frames and natural video frames. According to results, it has high accuracy level for single and multi-object tracking.     

Stochastic modeling of particle motion along a sliding conveyor

The sliding conveyor consists of a plane surface, known as the track, along which particles are induced to move by vibrating the bed sinusoidal with respect to time. The forces on the particle include gravity, bed reaction force and friction. Because friction coefficients are inherently variable, particle motion along the bed is erratic and unpredictable. A deterministic model of particle motion (where friction is considered to be known and invariant) is selected and its output validated by experiment. Two probabilistic solution techniques are developed and applied to the deterministic model, in order to account for the randomness that is present. The two methods consider particle displacement to be represented by discrete time and continuous time random processes, respectively, and permits analytical solutions for mean and variance in displacement versus time to be found. These are compared with experimental measurements of particle motion. Ultimately this analysis can be employed to calculate residence‐time distributions for such items of process equipment. © 2009 American Institute of Chemical Engineers AIChE J, 2010     

TENET: a new hybrid network architecture for adversarial defense

International Journal of Information Security - Deep neural network (DNN) models are widely renowned for their resistance to random perturbations. However, researchers have found out that these...     

Adversarial security mitigations of mmWave beamforming prediction models using defensive distillation and adversarial retraining

International Journal of Information Security - The design of a security scheme for beamforming prediction is critical for next-generation wireless networks (5G, 6G, and beyond). However, there is...