DYNAMIC AND HYBRID NEURAL MODEL OF THERMAL DRYING IN A FLUTDIZED BED

ABSTRACT

A preliminary study aimed at comparing Classical Dynamic Neural Modelling (CDNM) and Hybrid Neural Modelling (HNM) to describe thermal dewatering process in a fluidized bed is presented Two schemes of HN modelling were developed to find the most efficient way of combining a classical mathematical model of the process and Artificial Neural Network (ANN). CDN model was developed using “moving window” technique. In the first scheme of HNM a feed-forward ANN was trained to predict evaporation rate and heat flux in the drying process. In the second scheme of the HN model, ANN was used to determine heat transfer coefficient only. Excellent prediction of drying process by HNM is proved.     

Dyes based on a 1,4‐naphthoquinone skeleton as new type II photoinitiators for radical polymerisation

Photoredox pairs consisting of 1,4‐naphthoquinone dyes and commercially available hydrogen donors (2‐mercaptobenzoxazole, 2‐mercaptobenzothiazole, 2‐mercaptobenzimidazole and 2,5‐dimercapto‐1,3,4‐thiadiazole) are found to be effective initiator systems for the radical polymerisation of trimethylolpropane triacrylate under visible light. The efficiency of these initiator systems is discussed in terms of the free energy change for the electron transfer process from the dye to the hydrogen donor. The results show that the photoinitiation ability of tested photoredox pairs depends on the structure of both the dye and the hydrogen donor.     

Experimental study of cohesive strain prior to crack initiation in constant force single cantilever beam test

Retarded deformation at the bond line edge of a thick, viscoelastic adhesive layer is observed using digital image correlation. Such information is required for proposing physical crack onset/propagation parameters which take into account viscoelastic and viscous mechanisms in the evaluation of dissipated energy. A complex stress/strain redistribution is observed in the early stage after specimen loading. The results illustrate that viscoelasticity dissipates a considerable amount of energy prior to crack nucleation and the lack of predictive models to account for that phenomenon.     

Polyurethane foams from melamine solutions in reactive solvents based on ethyl methyl ketone

This work presents conditions and method for obtaining foamed melamine–formaldehyde–butanone (Mel‐F‐MEK) materials of improved thermal stability. They were obtained from melamine solution in reactive solvents based on ethyl methyl ketone and 4,4′‐diphenylmethane diisocyanate. Some properties of obtained polyurethane foams were examined, e.g., apparent density, water absorption, dimensional stability, thermal conductivity, flammability, as well as static and dynamic thermal stability and compressive strength. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and Characterization of Low Viscosity Dimethacrylic Resin Based on Isosorbide

In this article, synthesis and properties of novel dimethacrylic resin (ISETDMA) based on human friendly, biobased isosorbide was described. Its potential as a possible diluting monomer for medical applications, mainly dental restorative systems was assessed. The resin was obtained in two‐step synthesis including ethoxylation of isosorbide and subsequent methacrylation with methacryloyl chloride. ¹HNMR, FTIR, and electrospray ionization mass spectroscopy (ESI‐MS) techniques were used to identify products. ISETDMA as well as composition with 2,2‐bis[4‐(2‐hydroxy‐3‐methacryloyloxypropoxy)phenyl]propane were polymerized using UV initiator IRGACURE 651. Double bond conversion, polymerization shrinkage, water sorption, and sol fraction of resulting polymers were determined. Selected mechanical (flexural strength and modulus, Brinell hardness) and thermomechanical (dynamic mechanical analysis) properties were also investigated. Triethylene glycol dimethacrylate and 2,2‐bis(4‐(2‐methacryloxyethyl‐1‐oxy)phenyl)propane based homopolymers and copolymers were prepared as reference for comparison of particular properties. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2514–2522, 2013     

Comparative Analysis of Energetic Properties of Ti6Al4V Titanium and EN-AW-2017A(PA6) Aluminum Alloy Surface Layers for an Adhesive Bonding Application

The purpose of this article is to present energetic properties of surface Ti6Al4V titanium as well as surface EN-AW-2017A(PA6) aluminum alloy layers. Values of surface free energy after selected mechanical operations and ozonation were compared. In addition, the influence of different values of ozone concentration on surface layer energetic activation was analyzed. Dispersive and polar components of surface free energy were of particular concern. Comparative evaluation of shearing strength of Ti6Al4V titanium and EN-AW-2017A(PA6) aluminum alloy single-lap adhesive bonded joints were presented. Results can be used as pro-ecological methods of titanium and aluminum alloys preparing for applications where adhesive phenomenon is important.     

Effect of immobilization of titanocene catalyst in aralkyl imidazolium chloroaluminate media on performance of biphasic ethylene polymerization and polyethylene properties

1-(2-Phenylethyl)-3-methylimidazolium and 1-benzyl-3-methylimidazolium chloroaluminates, [Ph-C₂mim][AlCl₄] and [Bzlmim][AlCl₄], were applied as media of the Cp₂TiCl₂ catalyst for biphasic ethylene polymerization. The studied aralkyl ionic liquids ensure greater stability of the catalyst at higher temperatures and more regular morphology of the produced polyethylene than analogous 1-n-alkyl-3-methylimidazolium chloroaluminates. The alkylaluminium compound participates in the termination reaction of the polymer chain. The catalyst is stable and enables recycling of the ionic liquid phase in the consecutive polymerization reactions. The [Ph-C₂mim][AlCl₄] ionic liquid and AlEt₂Cl alkylaluminium compound turned out to be the most suitable for the biphasic process. The influence of the kind of ionic liquid, alkylaluminium compound (AlEt₂Cl and AlEtCl₂), activator/catalyst molar ratio, reaction temperature, reaction time and catalyst recycling on the polymerization performance as well as polyethylene properties such as molecular weight (M _w ), polydispersity, melting temperature, crystallinity degree, bulk density and particle size is presented.     

Behavior of Cetyltrimethylammonium Bromide, tert-Octylphenol (9.5 EO) Ethoxylate and Ethanol Mixtures at the Water–Air Interface

The surface tension measurements of aqueous solutions of p‐(1,1,3,3‐tetramethylbutyl)phenoxypoly(9.5)ethylene glycol or tert‐octylphenol ethoxylate (TOP10) and cetyltrimethylammonium bromide (CTAB) mixtures with ethanol were carried out in the range of the total concentration of CTAB and TOP10 mixtures from 1 × 10^?7 to 1 × 10^?2 M and ethanol from 0 to 17.13 M. In the CTAB and TOP10 mixtures, the mole fractions of TOP10 were equal to 0.2; 0.4; 0.6; and 0.8, respectively. The results obtained were compared to those calculated from the Fainerman and Miller equation developed for ideal mixtures of two homologous surfactants, as well as from the Connors equation derived for the concentrated organic solutions. The calculations of the surface tension from the Fainerman and Miller equation were carried out treating the solvent and solute in a few different ways. The differences between the measured and calculated values of the surface tension were discussed in the light of molecular interaction parameter and the composition of the surface layer. The composition of the mixed surface layer at the solution‐air interface was evaluated according to Rosen using the nonideal solution theory with the assumption that water with ethanol is a mixed solvent. Knowing the values of mole fractions of CTAB and TOP10 in the surface layer, the molecular interaction parameter was determined.     

Fiber Specific Changes in Sphingolipid Metabolism in Skeletal Muscles of Hyperthyroid Rats

Thyroid hormones (T₃, T₄) are well known modulators of different cellular signals including the sphingomyelin pathway. However, studies regarding downstream effects of T₃ on sphingolipid metabolism in skeletal muscle are scarce. In the present work we sought to investigate the effects of hyperthyroidism on the activity of the key enzymes of ceramide metabolism as well as the content of fundamental sphingolipids. Based on fiber/metabolic differences, we chose three different skeletal muscles, with diverse fiber compositions: soleus (slow-twitch oxidative), red (fast-twitch oxidative-glycolytic) and white (fast-twitch glycolytic) section of gastrocnemius. We demonstrated that T₃ induced accumulation of sphinganine, ceramide, sphingosine, as well as sphingomyelin, mostly in soleus and in red, but not white section of gastrocnemius. Concomitantly, the activity of serine palmitoyltransferase and acid/neutral ceramidase was increased in more oxidative muscles. In conclusion, hyperthyroidism induced fiber specific changes in the content of sphingolipids that were relatively more related to de novo synthesis of ceramide rather than to its generation via hydrolysis of sphingomyelin.     

Dynamic Combinatorial Chemistry in Chemical Catalysis

Despite the progress in the field of dynamic combinatorial chemistry (DCC), dynamic combinatorial catalysis has received considerably less attention. Some first studies, however, have provided proof of principle and demonstrated that DCC-based approaches are also applicable in catalyst development. This provides interesting new tools that are complementary to rational catalyst design and traditional combinatorial strategies. As such, DCC may become highly valuable in the field of dynamic combinatorial catalysis, due also to the practical importance of catalysis. In this review we focus on the principles of dynamic combinatorial catalysis and provide an overview by the introduction of different concepts related to the development of libraries and selection procedures in catalysis.