Delamination of sodium montmorillonite in PA6 in the presence of melamine polyphosphate

This study describes the influence of melamine polyphosphate (MPP) flame retardant addition on layered structure of virgin sodium montmorillonite (MMT) in PA6/MMT system obtained in extrusion process. It was found that the extrusion of the PA6/MMT binary system in co‐rotating twin screw extruder gives intercalated clay nanocomposites, while during extrusion of ternary PA6/MMT/MPP composite, full exfoliation of clay was obtained in the system. Structure of the composites was proved utilizing wide angle X‐ray scattering and transmission electron microscopy techniques. Exfoliation of MMT in ternary PA6/MMT/MPP system was also confirmed by rheological studies (viscosity and creep measurements) which were carried out using rotational rheometer. Young's modulus of PA6/MMT/MPP was found to be ~25% greater comparing to PA6/MPP of the same filling level. Cone calorimetry experiments proved decrease of heat release rate peak of PA6/MMT/MPP by ~55% comparing to PA6/MPP with the same total filling level. Copyright © 2017 John Wiley & Sons, Ltd.     

On Asymptotic Stability and Sweeping of Collisionless Kinetic Equations

We study a collisionless kinetic equation describing density distribution function of the position and velocity of particles moving in a slab with finite thickness and with a partly diffusive boundary reflection. In particular, we deal with existence of an invariant density and with the convergence to the equilibrium. We also study the long time behavior of densities when the equilibrium does not exists.     

On the application of the plastic spin concept for the description of anisotropic hardening in finite deformation plasticity

The aim of the paper is to fill the gap between the general theoretical formulation of the constitutive relations for plastic spin and practical applications for proper prediction of material behavior at finite plastic deformations and anisotropic hardening. An approximation to the representation of the general constitutive equation for plastic spin is considered and the pertinent substructure corotational rate is applied to formulate the relation for rigid-plastic material with kinematic hardening. The simple shear traction problem is analysed and the proposed model is verified with the experimental results of Swift. The merits of the present proposal vis-à-vis the existing theories are discussed.     

Spontaneous and diastereoselective aldol reactions of cyclic β-amino ketones in the presence of water

Direct aldol reactions of 4-methyl-1-piperidone, tropinone and granatanone (pseudopelletierine) take place spontaneously in the presence of water without any catalyst or additional reagents. The anti/syn-diastereoselectivity of the aqueous aldol reaction depends on the amount of water used. The syn-selectivity of the reaction is probably due to the thermodynamic control. Excellent atom economy and low E factors together with anti-selectivity as high as 98:2 for the tropinone aldol were obtained.     

Comfortable, flexible upholstery fire barriers on base of bast, wool and thermostable fibres

The paper presents elastic barrier materials developed at the INF which play a role of filling and fire barrier material at the same time in upholstery furniture, reducing the development and spread of fire on flammable materials. The presented results of flammability and biophysical tests confirm the comfort of products.The developed barrier materials use natural fibres (wool, flax FR) characterized by good air permeability, hygroscopicity, moisture transport, elimination of electrostatic charges and have effect on climate of interiors also when blended with thermostable fibres such as Polyacrylate. These flexible structures based on blend of natural fibres and thermostable fibres with at least two barrier effects i.e. durable resistance to fire, thermal insulation, control of electrostatic phenomena.     

Integrated microfluidic device for the separation and electrochemical detection of catechol estrogen-derived DNA adducts

Catechol estrogen-derived DNA adducts are formed as a result of the reaction of catechol estrogen metabolites (e.g., catechol estrogen quinones) with DNA to form depurinating adducts. Developing a new methodology for the detection of various DNA adducts is essential for medical diagnostics, and to this end, we demonstrate the applicability of on-chip capillary electrophoresis with an integrated electrochemical system for the separation and amperometric detection of various catechol estrogen-derived DNA adducts. A hybrid PDMS/glass microchip with in-channel amperometric detection interfaced with in situ palladium decoupler is utilized and presented. The influence of buffer additives along with the effect of the separation voltage on the resolving power of the microchip is discussed. Calibration plots were constructed in the range 0.4–10 μM with r ² ≥ 0.999, and detection limits in the attomole range are reported. These results suggest that on-chip analysis is applicable for analyzing various DNA adducts as potential biomarkers for future medical diagnostics.     

Light driven reactions of single physisorbed azobenzenes

We present a successful attempt of decoupling a dye molecule from a metallic surface via physisorption for enabling direct photoisomerization. Effective switching between the isomers is possible by exposure to UV light via the rotation pathway.     

Retrieving the heat transfer coefficient for jet impingement from transient temperature measurements

Algorithm of retrieving the heat transfer coefficient (HTC) from transient temperature measurements is presented. The unknown distributions of two types of boundary conditions: the temperature and heat flux are parameterized using a small number of user defined functions. The solutions of the direct heat conduction problems with known boundary temperature and flux are expressed as a superposition of auxiliary temperature fields multiplied by unknown parameters. Inverse problem is formulated as a least squares fit of calculated and measured temperatures and is cast in a form of a sum of two objective functions. The first results originates from an inverse problem for retrieving the boundary temperature the second comes from the inverse problem for reproducing the boundary heat flux. The final form of the objective function is obtained by enforcing constant in time value of the heat transfer coefficient. This approach leads to substantial regularization of the results, when compared with the standard technique, where HTC is calculated from separately reconstructed temperature and heat flux on the boundary. The validation of the numerical procedure is carried out by reconstructing a known distribution of the HTC using simulated measurements laden by stochastic error. The proposed approach is also used to reconstruct the distribution of the HTC in a physical experiment of heating a cylindrical sample using an impinging jet.     

Deformations of algebroid stacks

In this paper we consider deformations of an algebroid stack on an étale groupoid. We construct a differential graded Lie algebra (DGLA) which controls this deformation theory. In the case when the algebroid is a twisted form of functions we show that this DGLA is quasiisomorphic to the twist of the DGLA of Hochschild cochains on the algebra of functions on the groupoid by the characteristic class of the corresponding gerbe.     

BOOK REVIEW: Loops,Knots, Gauge Theories and Quantum Gravity,by Rodolfo Gambini and Jorge Pullin

General Relativity and Gravitation -