Search results for "CONST"
showing 10 items of 7706 documents
Electronic and Steric Effects: How Do They Work in Ionic Liquids? The Case of Benzoic Acid Dissociation
2010
The need to have a measure of the strength of some substituted benzoic acids in ionic liquid solution led us to use the protonation equilibrium of sodium p-nitrophenolate as a probe reaction, which was studied by means of spectrophotometric titration at 298 K. In order to evaluate the importance of electronic effect of the substituents present on the aromatic ring, both electron-withdrawing and -donor substituents were taken into account. Furthermore, to have a measure of the importance of the steric effect of the substituents both para- and ortho-substituted benzoic acids were analyzed. The probe reaction was studied in two ionic liquids differing for the ability of the cation to give hydr…
Heterogeneous fenton oxidation using magnesium ferrite nanoparticles for ibuprofen removal from wastewater: optimization and kinetics studies
2020
In this study, the catalytic properties of Fenton-like catalyst based on magnesium ferrite nanoparticles for IBP degradation were examined. Structural and morphological studies showed the low crystallinity and mesoporous structure for the catalyst obtained via a glycine-nitrate method. The influences of catalyst dosage, oxidant concentration, and solution pH on the pollutant degradation were investigated. The pseudo-first-order model describes kinetic data, and under optimal condition (catalyst dose of 0.5 g L-1, H2O2 concentration of 20.0 mM, and pH of 8.0), apparent rate constant reached 0.091 min-1. It was shown that Fenton reaction was mainly induced by iron atoms on the catalyst surfac…
Self-Efficacy Between Previous and Current Mathematics Performance of Undergraduate Students: An Instrumental Variable Approach to Exposing a Causal …
2021
PurposeSelf-efficacy has been argued theoretically and shown empirically to be an essential construct for students’ improved learning outcomes. However, there is a dearth of studies on its causal effects on performance in mathematics among university students. Meanwhile, it will be erroneous to assume that results from other fields of studies generalize to mathematics learning due to the task-specificity of the construct. As such, attempts are made in the present study to provide evidence for a causal relationship between self-efficacy and performance with a focus on engineering students following a mathematics course at a Norwegian university.MethodThe adopted research design in the presen…
Diseño y validación de un instrumento para evaluar el valor social subjetivo de la educación
2017
Actualmente, la importancia que se atribuye a la educación, tanto desde la percepción social, grupal o individual, puede estar repercutiendo sobre el proceso de enseñanza-aprendizaje. En esta línea, este estudio se centra en diseñar y validar un instrumento de evaluación del Valor Social Subjetivo de la Educación (VSE-Subjetivo) dentro del marco de referencia del Modelo de Evaluación para la Cohesión Social. A partir de una revisión documental internacional sobre el concepto a nivel evaluativo y una validación cruzada, tanto a nivel estatal (España) como a nivel internacional entre varios países (Argentina, España y República Dominicana), presentamos el constructo teórico y sus cuatro dimen…
The re-emergence of the condition of insularity in the Italian and European legal system
2022
The essay deals with the question of the conditions of insularity in the European and Italian legal systems by analyzing the regulatory evolutions and the studies of the Regions on the subject up to the recognition referred to in the Constitutional law n. 2 of 2022 (art.119, 6 paragraph)
Semi-blind Source Extraction Methods: Application to the measurement of non-contact physiological signs
2018
Non-contact physiological measurements are highlydesirable in many biomedical fields such asdiagnosis of infants, geriartic patients, patients withextreme physical trauma, and fitness and well-being.Remote photoplethysmography is increasingly beingused for non-contact measurement of heart rate fromvideos which is one of the most common biomedicalproperty required for most medical diagnosis. Oneof the common techniques for performing remotephotoplethysmography involves using Blind SourceSeparation (BSS) methods to extract the cardiacsignal from video data.In this context, the objective of this thesis is todevelop different methods in the field of extractionand separation of sources by improv…
Determination of the atmospheric precipitation pH value on the basis of the analysis of lichen cationoactive layer constitution
2006
Studies of equilibria and kinetics of the ion exchange process between the surrounding (water solution) and lichens prove that the number of mobile hydrogen ions bonded in lichens depends on the concentration of hydrogen ions in the precipitation with which the lichens are in contact and the type and concentration of other cations contained in the precipitation. The measurement of these values was suggested; as a result, it enabled to determine the pH of precipitation by determination of mobile cations bonded in exposed or naturally grown lichens. The studies were conducted on Hypogymnia physodes lichens.
Intelaiature lignee leggere quale presidio antisismico nell'architettura tradizionale di area mediterranea
2017
L’accresciuta attenzione nei confronti degli aspetti costruttivi dell’edificato storico, associata all’analisi delle tecniche attraverso la ricerca archivistica, ma ancor più gli interventi di restauro e recupero che punteggiano i centri storici per iniziativa pubblica e privata consentono di ritrovare -nascoste anche all’occhio attento che le sa riconoscere- le intelaiature a graticcio ligneo: teatri ad intera struttura lignea, la configurazione interna di saloni ed ambienti di rappresentanza di palazzi nobiliari, chiese, conventi o monasteri ed anche l’edilizia diffusa che definiremmo “di base” testimoniano la capillare applica-zione del sistema costruttivo, con invarianti ed originalità …
Action-Depicting Gestures and Morphosyntax: The Function of Gesture-Speech Alignment in the Conversational Turn
2021
The current study examines the role of action-depicting gestures in conversational turns by focusing on their semantic characteristics and temporal position in relation to their verbal affiliates (action verbs or more complex verb phrases). The data are video recordings of naturally occurring interactions in multilingual construction sites in Norway. The analysis distinguishes two modes of action depiction: generic depictions, which represent the action as a general type, and contextualized depictions, which in addition include deictic references to the spatio-material environment or iconic representations of the specific manner of action performance. These two modes typically occupy differ…
Simulation of Fatigue Delamination Growth in Composites with Different Mode Mixtures
2007
A numerical model, obtained by implementing a cyclic damage model in the framework of an interface element, is here proposed to reproduce the crack growth in laminated composites subjected to cyclically repeated loads. This model, which differs from the few studies in the literature on the topic, applies not only to single fracture modes but also to mixed modes, and to constant or variable crack growth rates. The applied load (in terms of force or displacement) is assumed to oscillate between a minimum and a maximum constant value. The Paris curve can be reproduced with accuracy once some parameters in the numerical model are tuned with experiments. These parameters are preliminarily found…