Search results for "testing"
showing 10 items of 1769 documents
The Role of Planarity versus Nonplanarity in the Electronic Communication of TCAQ-Based Push–Pull Chromophores
2018
Donor-acceptor-substituted alkynes, endowed with 11,11,12,12-tetracyano-9,10-anthraquinodimethane (TCAQ) and N,N-dimethylaniline (DMA) units, have been further functionalized by a [2+2] cycloaddition with tetracyanoethylene (TCNE) followed by a subsequent retro-electrocyclization to form distorted nonplanar structures with bridging 1,1,4,4-tetracyanobuta-1,3-diene (TCBD) units. Comprehensive spectroscopic, electrochemical, and computational studies have been carried out to compare the electronic communication in planar (alkyne bridges) and nonplanar (TCBD bridges) TCAQ-based push-pull chromophores. Cyclic voltammetry and UV/Vis absorption measurements confirm the electronic communication be…
Multicomponent solid dispersion a new generation of solid dispersion produced by spray-drying
2020
Abstract The term “multicomponent solid dispersion” is widely used in recent literature to describe solid formulations consisting of a special excipient's mixture and active molecules finely dispersed. However, this term has not yet been defined. In this review, we aimed to improve the definition of multicomponent solid dispersions as a new generation of solid dispersions capable to improve both formulation issues and the therapeutic effect of the final dosage form. As it is well-known the use of solid dispersions to improve drug dissolution rate and solubility, this review describes the field of solid dispersions as well as the formulation strategies available for their production. In part…
Limits of the linear viscoelastic behaviour of polyamide 66 filled with TiO2 nanoparticles: Effect of strain rate, temperature, and moisture
2008
Abstract Limits of linear viscoelastic behaviour of TiO 2 nanoparticle-filled polyamides are estimated quantitatively by the results of uniaxial tension tests. The stress limit of the filled polymer is higher than that of the un-filled one. Their values are the lower, the higher the temperature and moisture content of test specimens, and the lower, the lower the strain rate. The concept of an energy threshold for the linear viscoelastic behaviour is used to comprehensively characterize the limits over a wide range of test conditions. The energy limit is not affected by the strain rate, temperature, or moisture, and its value for the filled polymer is higher than that for the un-filled one. …
Modeling the nonlinear deformation of flax-fiber-reinforced polymer matrix laminates in active loading
2015
In an attempt to fully utilize the mechanical properties of bast fibers in polymer-matrix composites, unidirectional (UD) or quasi-UD flax-fiber-reinforced composites are being developed and characterized. Their response in tension is markedly nonlinear both in on- and off-axis loading. A semiempirical tensor-linear model is applied to describe such deformation nonlinearity in active combined loading. The deformation model of UD ply, combined with an elementary laminate theory, is used to predict the stress–strain curves of laminated composites in tension. Reasonable accuracy of prediction is demonstrated for fiber-dominated layups.
Solvatochromy and electro-optical study of new fluorine-containing chromophores
1998
technology requires tailored functional materials which fulfill the demands for optimal operation parameters, reliability andprocessability. Organic chromophores and polymers which contain covalently bound chromophores are promising materialclasses which can satisfy a broad spectrum of demands on functional materials for photonics, and they are, therefore,favorites for the development of new photonic devices. However, it is almost impossible to satisfy all physico-chemical andtechnological requirements simultaneously with a polymer consisting of only one type of functional unit. The developmentof a series of different building blocks which allow to cover the whole range of physico-chemical …
The fractal calibration method applied to the characterization of polymers in solvent mixtures and in mixed gel packings by SEC.
2007
The size-exclusion chromatographic (SEC) behaviour of different solvent/polymer systems in three packing sets has been analysed from fractal considerations. The three-column sets studied are specifically formed by: (i) 'pure' micro-styragel, (ii) 'mixed' TSK Gel H(HR + XL + HR) and (iii) mixed TSK Gel H(XL + HR + XL). The experimental data reveals that in most of the systems assayed the classical universal calibration (UC) is not fulfilled, denoting the existence of secondary effects accompanying the main SEC mechanism. In order to obtain an accurate characterization of different polymers eluted in solvent mixtures and/or mixed packings, the use of a reliable and trusted calibration curve i…
Constant stretching rate experiments on low density polyethylene
1985
A simple apparatus for elongational test of molten polymers is presented. Its realiability is demonstrated by means of stress growth in constant stretching rate experiments and relaxation test on a low density polyethylene sample.
Comparative Biological Properties and Mineralization Potential of 3 Endodontic Materials for Vital Pulp Therapy: Theracal PT, Theracal LC, and Bioden…
2021
INTRODUCTION The aim of this study was to assess the biological properties and mineralization potential of the new Theracal PT (Bisco Inc, Schaumburg, IL) compared with its predecessor Theracal LC (Bisco Inc) and the hydraulic silicate-based cement Biodentine (Septodont, Saint-Maur-des-Fosses, France) on human dental pulp stem cells (hDPSCs) in vitro. METHODS Standardized sample discs were obtained for each material (n = 30) together with 1:1, 1:2, and 1:4 material eluates. Previously characterized hDPSCs were cultured with the different materials in standardized conditions, and the following assays were performed: a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, a woun…
Mechanical properties and XRD of Nafion modified by 2-hydroxyethylammonium ionic liquids
2013
In this work, the Nafion 112 membrane impregnated with 2-hydroxyethylammonium carboxylate ionic liquids have been investigated. The used ionic liquids were 2-hydroxyethylammonium formate [HEA]F, acetate [HEA]A and lactate [HEA]L. Prepared composite membranes Nafion/ionic liquid are characterized by mechanical testing, such as tensile test and creep test. It is found that ionic liquids decrease elastic modulus and creep compliance, but do not have significant effect on the tensile strength. Also, composite membranes were studied by wide angle X-ray diffraction. All ionic liquids shift the peak maximum to the lower angle. In this work, only biodegradable ionic liquids were used for composite …
Experimental Evaluation on Narrow Band Power Line Communication in Medium and Low Voltage Smart Grids
2013
The aim of this work is to perform a feasibility study on the power line communication for the development of a new generation of interface devices (IDs) for smart grid and energy storage applications. More in detail, this paper deals with one of the most important issues on this topic, which is the communication system. Among the existing communication technologies, the study is focused on power line communications (PLCs). After an analysis of the state of the art in the field, the main aspects are analyzed, concerning the open issues on the use of PLCs, especially for medium voltage (MV) and low voltage (LV) systems. In this work the use of PLC in MV-LV networks is investigated, by means …