Search results for " modelling"

River water quality modelling: a parsimonious model approach

2009

Biological Nutrient Removal Model No. 2 (BNRM2): a general model for wastewater treatment plants

2013

This paper presents the plant-wide model Biological Nutrient Removal Model No. 2 (BNRM2). Since nitrite was not considered in the BNRM1, and this previous model also failed to accurately simulate the anaerobic digestion because precipitation processes were not considered, an extension of BNRM1 has been developed. This extension comprises all the components and processes required to simulate nitrogen removal via nitrite and the formation of the solids most likely to precipitate in anaerobic digesters. The solids considered in BNRM2 are: struvite, amorphous calcium phosphate, hidroxyapatite, newberite, vivianite, strengite, variscite, and calcium carbonate. With regard to nitrogen removal via…

L’algoritmo come strumento didattico in fisica: modellizzazione dei gas ideali classici e quantistici

2011

Viene discussa una procedura per la modellizzazione dei gas ideali quantistici. Inoltre, viene evidenziata l’importanza di supportare le incomplete rappresentazioni mentali degli studenti, in relazione ad argomenti complessi di meccanica statistica e termodinamica, con accurati modelli fisici aventi validità predittiva e fondati sull’ipotesi di possibili meccanismi di funzionamento. L’idea alla base dell’approccio proposto è quella che, in alcuni casi, anche la sola discussione dei risultati di un algoritmo o di un modello può essere sufficiente a migliorare la comprensione di un sistema fisico particolarmente complesso.

A new expression of the slope length factor to apply USLE-MM at Sparacia experimental area (Southern Italy)

2013

Abstract Predicting soil loss due to water erosion by empirical models is useful to assess the severity of the phenomenon in an area of interest and to predict the effect of alternative soil erosion control practices. The USLE scheme cannot be used at the Sparacia experimental area (Sicily, South Italy) to predict event soil loss per unit plot area, Ae, because experimental data suggest that, generally, Ae does not increase with plot length, λ. The USLE-MM scheme uses the runoff coefficient, QR, as an additional independent variable in order to develop an empirical model allowing prediction of storm soil loss values that do not necessarily increase with λ. According to this model, Ae is exp…

The effect of physical education students' beliefs and values on their physical activity: A growth mixture modelling approach

2013

This study examined the change in adolescents' expectancy-related beliefs and task values towards physical education (PE). In addition, the physical activity (PA) growth trajectories of the identified adolescent subpopulations were examined. This study comprised 812 students (age M = 12.31, range: 11–13), who answered questionnaires four times during Grades 6–9. This study found that expectancy-related beliefs declined, while task values increased across the middle school transition. Adolescents who valued PE highly and experienced an increase in their expectancy-related beliefs became physically more active across time, while adolescents with the lowest levels and the most negative change …

Trajectories of depressive symptoms during emerging adulthood: Antecedents and consequences

2008

In order to examine what kinds of trajectories of depressive symptoms young adults show during emerging adulthood, and their antecedents and consequences, 297 university students completed the revised Beck's depression inventory seven times over a 10-year period, and other measures at the beginning and the end of the study. The growth mixture modelling for depressive symptoms ended up in a 3-group solution: 23% of the participants were typified by a low level of symptoms, 61% showed a moderate level, and 16% fell into the third group with high and increasing levels of depressive symptoms during emerging adulthood. Those on the high-depressive trajectory had a poorer quality of relationships…

Mechanisms for Translocation of Heavy Metals from Soil to Epigeal Mosses

2011

The mechanisms for translocation of heavy metals from soil to epigeal mosses were investigated. The first mechanism was demonstrated for (137)Cs and involved the uplifting of the pollutant-containing dust from the soil, followed by the local secondary deposition on surfaces of epigeal mosses and epiphytic lichens. The second mechanism involved the diffusion of metal cations from the soil through water wetting the moss into the gametophyte. The mechanism was demonstrated by measuring the electric conductance of wetted gametophytes with single ends immersed in solutions of Cu and Na salts. In addition, the concentrations of Cu and Cd were compared in moss samples exposed to the natural soil a…

4D paleoenvironmental evolution of the Early Triassic Sonoma Foreland Basin (western USA)

2017

In the wake of the Mesozoic, the Early Triassic (~251.95 Ma) corresponds to the aftermath of the most severe mass extinction of the Phanerozoic: the end-Permian crisis, when life was nearly obliterated (e.g., 90% of marine species disappeared). Consequences of this mass extinction are thought to have prevailed for several millions of years, implying a delayed recovery lasting the whole Early Triassic, if not more. Several paradigms have been established and associated to a delayed biotic recovery scenario expected to have resulted from harsh and deleterious paleoenvironments. These paradigms include a global anoxia in the marine realm, a “Lilliput” effect, and the presence of “disaster” tax…

Modelling of Pulsed Electro Acoustic Method for Space Charge Detection on Single and Multilayer Dielectrics

Probabilité d'apparition d'un phénomène parasitaire et choix de modèles de régression logistique

2007

Epidemiological processes are now using spatial statistics and modelling tools. The main objective of most health risks studies consists in identifying potential contamination sources and factors capable of explaining their localization. Health data often prove binary (typically presence/absence) and specific methods such as binary logistic regression have to be used. This method's output consists in a probability for the pathogen of interest. A posterior classification of each sample is then conducted using a probability threshold. The method used to maximize this threshold is called the ROC curve which consists in giving a representation of the behaviour of the model and then to choose th…