Simulation of hydrodynamic behaviour and mass transfer efficiency of reduced pressure distillation

A random packing hydrodynamic simulator is designed specially to carry out experiments under reduced pressures with a counter-current flow air/water system. The simulator results (air/water system) compared to those obtained in a real packed distillation column (benzylchloride/ ethylbenzene system) show a good agreement between hydrodynamic parameters like pressure drop, flooding flow rate, and total liquid hold-up. Empirical relationships derived from the simulator experimental results are proposed allowing the calculation of the pressure drop in a packed distillation column, operating in the pressure range between 10 kPa and atmospheric pressure. The influence of reduced pressure on the HETP in the distillation column and interfacial area in the simulator was also investigated.     

Non‐constraining Online Signature Reconstruction System for Persons with Handwriting Problems

This paper presents a new non‐constraining online optical handwritten signature reconstruction system that, in the main, makes use of a transparent glass pad placed in front of a color camera. The reconstruction approach allows efficient exploitation of hand activity during a signing process; thus, the system as a whole can be seen as a viable alternative to other similar acquisition tools. This proposed system allows people with physical or emotional problems to carry out their own signatures without having to use a pen or sophisticated acquisition system. Moreover, the developed reconstruction signature algorithms have low computational complexity and are therefore well suited for a hardware implementation on a dedicated smart system.     

Electronic and Electrical Conductivity of AB and AA-Stacked Bilayer Graphene with Tunable Layer Separation

This humble work attempts to study the electronic and electrical conductivity characteristics of AB and AAstacked bilayer graphene (BLG) sheet, by using ab initio calculation. The electronic transport coefficient was calculated by using Boltzmann transport equations implanted in Boltztrap package at various temperatures from 80 to 380 K. First, this study will begin to experiment an interlayer spacing from 3.55 and 3.35 Å respectively for AA and AB-BLG. If the distance between the layers is more than 5.00 Å, the increase or decrease of energy does depend on the interlayer spacing so band gap is equal to zero. The electrical conductivity of AA and AB-BLG is compared to the experimental electrical conductivity of graphene monolayer under increasing spacing between layers to 4.00 Å. Band gap decreases with the increasing space while conductivity increases with increasing space. AA-BLG electrical conductivity shows a value near to the experimental electrical conductivity of graphene ribbon for 4.00 Å at 380 K. Nevertheless, the distance variation does not much affect the electronic and electrical characteristics of AB-BLG. In addition, the increase between the interlayer distances does not influence so much the electrical conductivity. Therefore, increasing the distance between interlayers decreases the electrical conductivity due to the increasing of band gap.     

Synthesis of isosorbide based polyurethanes: An isocyanate free method

The synthesis of isocyanate free polyurethanes is a major concern. This paper first reports the synthesis of new biobased isosorbide dicyclocarbonates from isosorbide. Then polyhydroxyurethanes (PHUs) were synthesized by a cyclocarbonate–amine step growth polyaddition with four commercial diamines (e.g. jeffamine D-400, 1,10 diaminodecane, diethylenetriamine and isophoronediamine). These unprecedented products, obtained with high yield, were characterized by ¹H NMR, FTIR, DSC, SEC and TGA analyses. PHUs exhibited glass transition temperatures from ?8 °C to 59 °C, and degradation temperatures (Td 5%) between 234 °C and 255 °C. Last but not least, the compounds produced during the degradation of these PHUs were analyzed by ATG-IR technique and showed that carbon dioxide and secondary amines are released.     

Feedback stabilization of homogeneous polynomial systems of odd degree in the plane

In this paper, we give some tools for the construction of homogeneous feedback which stabilizes homogeneous polynomial systems of odd degree in the plane.     

User’s behavior study for smart houses occupant prediction

This paper deals with the smart house occupant prediction issue based on daily life activities. Based on data provided by nonintrusive sensors and devices, our approach use supervised learning technics to predict the house occupant. We applied support vector machines classifier to build a behavior classification model and learn the users’ habits when they perform activities for predicting and identifying the house occupant among a group of inhabitants. We analyzed the publicly available dataset from the Washington State University smart apartment tesbed. We particulary studied the grooming, having breakfast and bed to toilet activities. The results showed a hight prediction precision and demonstrated that each user has his own manner to perform his daily activities and can be easily identified by just learning his habit.     

On residual empirical processes of GARCH‐SM models: application to conditional symmetry tests

Abstract. Considering the generalized autoregressive conditionally heteroskedastic with stochastic mean (GARCH‐SM) model, we establish in this article the consistency and the weak representation of a functional of its residual empirical process. Based on this result, a symmetry test for GARCH‐SM model is developed. Simulations are given to show the asymptotic behaviour and normality of the test statistic.     

Fire retardancy effect of phosphorus‐modified halloysite on polyamide‐11 nanocomposites

Halloysite nanotubes (HNTs) were successfully incorporated as flame retardants in polyamide‐11 (PA11) after their modification with methyl phosphonic acid. Fourier transform infrared spectroscopy, thermal gravimetric analysis (TGA) and pyrolysis–gas chromatography–mass spectrometry were used to evidence the functionalization of the clay. Raw and modified HNTs were then incorporated by melt mixing in PA11 at 20 wt%. Compositions containing both ammonium polyphosphate (APP) and HNTs were also prepared. TGA and pyrolysis combustion flow calorimeter exhibited enhancement in thermal stability upon incorporation of both raw and modified halloysite nanotubes while APP causes degradation at lower temperature. Cone calorimeter data showed that modified halloysite acts by forming an insulating barrier during the combustion, which limits heat and mass transfers. Moreover, elemental analysis of sample residues after cone test evidenced that a part of the phosphorus of the modified halloysite was transferred to the gaseous phase. These results suggest the full potential of halloysite as fire retardant agent for polyamides. POLYM. ENG. SCI., 59:526–534, 2019. © 2018 Society of Plastics Engineers