Search results for "Modell"
showing 10 items of 2134 documents
Modelling Nannochloropsis gaditana Growth in Reactors with Different Geometries, Determination of Kinetic Parameters and Biochemical Analysis in Resp…
2022
Microalgae are unicellular and photosynthetic microorganisms which grow thanks to inorganic salts, CO2 and light, and find applications in several fields thanks to their variety. The industrial application of microalgae has not often been fully exploited because of a lack of information about how microalgae respond to inputs and to different growth environments. In the present work a model able to predict the microalgae growth in reactors with different geometries was developed. We combined a Monod-like model for the specific growth rate with the Lambert-Beer law of homogeneous light distribution in thick photobioreactors. Kinetic parameters related to the cultivation of the microalga Nanno…
Constructal law optimization of a boiler
2017
The paper aims at the optimization of the design of a biomass boiler under the inspiration of the Constructal Law by Bejan. The boiler is of the smoke tubes typology, fuel being biomass pellets. The smoke tubes are 16 and are placed in a staggered configuration. A model is built in MATLAB environment, based on empirical correlations and the mean log temperature methodology. The analysis is based on the development of a wide parametric analysis that involves variations of diameters, numbers and positioning of the tubes. Results are based on the concept of the overall performance coefficient methodology and investigate both the pressure drops variation and the thermal power generated in the d…
Constraints on the spatial variation of Planck constant
2021
AbstractInspired by recently published researches, we present two protocols for setting an upper limit to the claimed variation of$$\hbar $$ħupon the position. The protocols, both within today state of art, involve the use of two delayed laser pulses driving an atom. The distinct positions of the laboratory, due to the Earth motion, affects$$\hbar $$ħand hence the atomic dynamics. The first protocol measures the difference in population of the atomic ground state while the second one the red-shift of the harmonics emitted by the atom in the two moments of the experiment. The protocols improve the reported upper limit of$$\varDelta \hbar /\hbar $$Δħ/ħ. The theory shows that$$\hbar (\varvec{r…
The Virtual Reconstruction of the Aesculapius and Hygeia Statues from the Sanctuary of Isis in Lilybaeum: Methods and Tools for Ancient Sculptures’ E…
2022
Thanks to recent technological developments in 3D surveys, computer graphics and virtual reality, new scenarios have been opened for the documentation and enhancement of ancient sculptures. When not totally preserved, sculptures can be digitally reproduced, modified and visualized to simulate their physical or virtual reconstruction in a non-invasive way for specialists or for dissemination aims. The virtual sculptural reconstruction process starts usually from the 3D survey of real fragments, and then continues by integrating missing parts with 3D modelling techniques by means of source evaluation. Along with primary data sources (reality-based model), secondary data sources (photos, drawi…
A simple procedure to improve the pressure evaluation in hydrodynamic context using the SPH
2009
In literature, it is well know that the Smoothed Particle Hydrodynamics method can be affected by numerical noise on the pressure field when dealing with liquids. This can be highly dangerous when an SPH code is dynamically coupled with a structural solver. In this work a simple procedure is proposed to improve the computation of the pressure distribution in the dynamics of liquids. Such a procedure is based on the use of a density diffusion term in the equation for the mass conservation. This diffusion is a pure numerical effect, similar to the well known artificial viscosity originally proposed in SPH method to smooth out the shock discontinuities. As the artificial viscosity, the density…
Modelling the effect of ascorbic acid, sodium metabisulphite and sodium chloride on the kinetic responses of lactic acid bacteria and yeasts in table…
2010
he goal of this work was to apply the Quasi-chemical primary model (a system of four ordinary differential equations that derives from a hypothetical four-step chemical mechanism involving an antagonistic metabolite) in the study of the evolution of yeast and lactic acid bacteria populations during the storage of Manzanilla–Aloreña table olives subjected to different mixtures of ascorbic acid, sodium metabisulphite and NaCl. Firstly, the Quasi-chemical model was applied to microbial count data to estimate the growth–decay biological parameters. The model accurately described the evolution of both populations during storage, providing detailed information on the microbial behaviour. Secondly…
La scuola nazionale dell'amministrazione tra modello francese e prospettive di riforma
2015
Il d.l. 90/2014 e il d.d.l. 1577-A di riorganizzaione delle pubbliche amministrazioni aprono a prospettive diriordino della SNA. L'occasione del riassetto induce preliminarmente a chiedersi quali debbano essere i compiti e le funzioni da affidare alla SNA. Più le funzioni e gli obiettivi sono eterogenei, più complesso e ibrido rischia di divenirne l'assetto giuridico. Già oggi la SNA è ricca di forme di ibridazione: ha natira giuridica di istituzione di alta cultura e formazione, ma è posta sotto la vigilanza della OCM; impiega personale docente di tipo misto; rilascia titolo post-laurea di elevata professionalità; opera in collaborazione con le università; ha un ruolo nel campo della ricer…
Dynamic modelling of a quadratic DC/DC single-switch boost converter
2017
This manuscript proposes the analysis of a Quadratic Boost Converter (QBC) transformer-less single switch typology. The state space average dynamic model and a constrained state space average model taking into account the mono-directional components of the converter (diodes, switches) have been analyzed. The static gain expression taking into consideration the parasitic elements of the converter and the small-signal transfer function of the QBC typology under study has been obtained. A sensitivity analysis has shown a high variation of the gain versus duty-cycle and of the derivative gain versus parasitic parameters of the converter in the range of the duty-cycle from 0.6 to 0.8 which is ra…
Tecniche avanzate per il rilevamento e la valorizzazione dei beni culturali. La chiesa rupestre di San Nicolò a Modica (RG)
2011
La Geomatica mette oggi a disposizione degli operatori che a vario titolo si occupano di beni culturali (storici, tecnici delle Soprintendenze, specialisti del recupero e del restauro, o anche solo studiosi) tecniche e strumentazioni di rilevamento sempre più veloci, accurate, affidabili. Spesso, la complessità della geometria dei manufatti da rilevare richiede l’uso di metodologie differenti ma integrate fra loro. Questo è, ad esempio, il caso del rilevamento della chiesa rupestre di San Nicolò a Modica per il quale si è fatto ricorso all’impiego di tecniche laser-scanning e fotogrammetriche digitali integrate. Questa integrazione ha permesso di ottenere un modello 3D virtuale foto realist…
Sperimentazione di procedure automatiche in fotogrammetria close-range per il rilievo di Beni Culturali
2011
Lo sviluppo di procedure automatiche in fotogrammetria close-range rappresenta attualmente un interessante argomento di ricerca soprattutto per quanto riguarda la fase di orientamento delle immagini. L’automazione del processo è principalmente dovuta all’integrazione tra tecniche derivate dalla Computer Vision e tecniche fotogrammetriche che ha consentito di sviluppare software scientifici e commerciali che consentono di eseguire automaticamente il processo di orientamento. L’obiettivo dello studio svolto è quello di eseguire una prima verifica sulle potenzialità delle procedure automatiche disponibili nel software PhotoModeler Scanner 2011 della EOS Systems. Tali procedure utilizzano la st…