Search results for "calor"

Hierarchical structure and cytocompatibility of fish scales from Carassius auratus

2014

Abstract To study the structure and the cytocompatibility of fish scales from Carassius auratus , scanning electron microscopy (SEM) was used to observe the morphology of fish scales treated with different processing methods. Based on varying morphologies and components, the fish scales can be divided into three regions on the surface and three layers in vertical. The functions of these three individual layers were analyzed. SEM results show that the primary inorganic components are spherical or cubic hydroxyapatite (HA) nanoparticles. The fish scales have an ~ 60° overlapped plywood structure of lamellas in the fibrillary plate. The plywood structure consists of co-aligned type I collagen …

The anion impact on the self-assembly of naphthalene diimide diimidazolium salts

2017

Naphthalene diimide diimidazolium salts differing in the anion nature were synthesized and their properties as well as their self-assembly behaviour were investigated. In particular, we took into consideration the N,N′-bis-(1-octyl-3-propylimidazolium)-naphthalene diimide cations and anions differing in size, shape and coordination abilities like [I−], [BF4−] and [NTf2−]. After determination of thermal behaviour, using differential scanning calorimetry and thermal gravimetric analysis, the electrochemical stability and redox properties were assessed using cyclic voltammetry. The self-assembly behaviour of the salts was investigated using concentration and temperature-dependent spectroscopic…

Halloysite nanotubes sandwiched between chitosan layers: novel bionanocomposites with multilayer structures

2018

This work is a contribution to the design of multilayer biocomposites based on halloysite nanotubes (HNTs) and chitosan. Both the polymer and nanotubular inorganic additive have been selected among easily available green materials. An innovative preparation procedure based on the sequential casting of chitosan and HNTs has been proposed in order to obtain multilayer composite biofilms. A physico-chemical investigation (contact angle measurements, differential scanning calorimetry, thermogravimetry) has been conducted to characterize the bionanocomposites. As evidenced by scanning electron microscopy, the nanocomposites possess an intermediate halloysite layer between the chitosan ones. The …

Influence of drying to the structure of lactitol monohydrate

1997

The purpose of this study is to find out the effect of the crystal water content on the crystal structure of lactitol monohydrate. Crystal water was removed by drying over silicagel at 40°C and by using phosphorus pentoxide as drying agent at 20°C. The amouts of water removals were identified by thermogravimetry, the melting points and the heat of fusions were calculated from the results of differential scanning calorimetry measurements and the structure of samples were identified by X-ray powder diffraction method. Over 23 w/w% of total water content could removed by gently drying until significant structural changes could be detected. The melting point of anhydrous lactitol obtained by dr…

Tunable Structure and Properties of Segmented Thermoplastic Polyurethanes as a Function of Flexible Segment

2019

Segmented thermoplastic polyurethanes (PUs) were synthetized using macrodiols with different functional groups (carbonate, ester, and /or ether) as a segment with a molar mass of 1000 and 2000 g/mol, and 4,4&rsquo

In vitro degradation of porous PLLA/pearl powder composite scaffolds

2013

Abstract The in vitro degradation behavior of poly- l -lactide (PLLA), PLLA/aragonite pearl powder and PLLA/vaterite pearl powder scaffolds was investigated. The scaffolds were soaked in phosphate buffer solution (PBS) up to 200 days. Scanning electron microscopy (SEM), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC) were used to observe any degradation of the scaffolds. Degradation behaviors such as changes in pH, porosity, bulk density, water absorption, weight loss and mechanical properties were discussed. The results show that a gradual increase of the pH in composite scaffolds can decrease the rate of hydrolysis of PLLA. PLLA/vaterite and PLLA/aragonite…

Laboratori virtual d'ensenyament-aprenentatge: solució numèrica de les equacions de conservació mitjançant volums finits aplicades a superfícies este…

2014

En este treball es presenta el disseny d’un Laboratori virtual d’ensenyament-aprenentatge per a la resolució d’un problema model de Transferència de la Calor en la matèria d’Enginyeria Tèrmica del II curs del Grau d’Enginyer de Tecnologies Industrials de la Universidad Rey Juan Carlos de Madrid. En l’àmbit de la Dinàmica de Fluids Computacional i per mitjà de l’ús del programari de simulació d’Ansys Fluent s’introduïx l’alumne al disseny, modelatge del sistema, resolució, anàlisi i validació del model. El resultat d’esta experiència d’aprenentatge és no sols la mera resolució del problema, inabordable amb mètodes didàctics tradicionals, sinó el desenvolupament de la combinació de destreses,…

General remarks on the role of the vestibular system in weightlessness

1987

Different methods are described to experimentally achieve weightlessness. Since the function of the otolith system depends on the presence of contact forces opposing gravity, it is disabled in weightlessness and may send misleading positional information to the brain. Without the contributions of the otolith system it is difficult in space to distinguish self-motion from object motion. Furthermore, the disintegration of information from the neck position receptors from those of the otolith system can lead to additional illusory positional sensations. Since the function of the semicircular canal system in previous space flights was found to be essentially undisturbed, the vestibular experime…

Three Determinants of Vestibular Hemispheric Dominance during Caloric Stimulation: A Positron Emission Tomography Study

2003

Comparison of three activity monitors for estimating sedentary time among children

2016

Background: Time spent sedentary appears to be associated with several health outcomes in adults, but findings are inconsistent in children. Further, the assessment of sedentary time represents a major challenge. The objectives of the present study were to determine whether 1) ActiGraph GT3X+, ActivPAL and SenseWear Armband Pro3 (SWA) provide comparable estimates of sedentary time in 9–12-year-old children, 2) these devices are valid compared with direct observation, and 3) ActivPAL discriminates between sitting and standing behavior. Methods: The sample was 67 children. Data were collected during three consecutive days in November 2012. To test the activity monitors in contexts related to …