Search results for "Ferro"
showing 10 items of 2451 documents
La torre del Tempo: il punto di vista del chimico
2013
L’obiettivo del presente lavoro è stato quello di valutare la tipologia di lega metallica, il suo degrado e la tipologia di vernice dell’opera in ferro policroma “La Torre del Tempo” di E. Tadini. A tale scopo sono state effettuate delle misure di Microscopia Ottica, Diffrattometria a raggi X, Spettroscopia micro-Raman e Spettroscopia NMR. The goal of this study was to evaluate the type and the of conservation state of the metal alloy and the type of varnish of samples coming from “La Torre del Tempo” E. Tadini. The samples were characterized by Optical Microscopy, X-ray Diffractometry, micro-Raman Spectroscopy and NMR spectroscopy.
High temperature ferro-paraelectric phase transition in tris(trimethylammonium) nonachlorodiantimonate(III) (TMACA) studied by X-ray diffraction meth…
2000
Abstract The structure of [NH(CH3)3]3Sb2Cl9, tris(trimethylammonium) nonachlorodiantimonate(III) (TMACA) has been determined at 295 K and 373 K, below and above the high temperature ferro-paraelectric phase transition. In both phases the anionic sublattice of TMACA is built of characteristic two-dimensional (Sb2Cl93−)n polyanionic layers lying in the bc plane. In room temperature, ferroelectric phase (monoclinic, Pc space group) there are three crystallographically non-equivalent trimethylammonium [NH(CH3)3]+ cations. Two of them are located between polyanionic layers and the third one, disordered, inside the cavity formed by six SbCl63− octahedra. In the high temperature paraelectric phase…
Viskozu magnētisku pilienu hidrodinamika zemfrekvences rotējošā laukā
2018
Tiek apskatīti viskozi magnētiskie pilieni, kas iegūti, destabilizējot ferrošķidrumu ar nātrija hlorīdu. Eksperimentāli ir novērotas to formu transformācijas zemfrekvences rotējošā magnētiskā laukā. Kvantitatīvi analizēta pilienu dinamika pie dažādiem rotējošā magnētiskā lauka parametriem. Izmantojot attēlu apstrādes metodes, tiek iegūti fizikālie parametri, kas raksturo magnētisko pilienu hidrodinamiskās un magnētiskās īpašības. Tas dod iespēju iegūtos rezultātus salīdzināt ar esošajiem teorētiskajiem modeļiem.
A statistical approach for calibrating a microsimulation model for freeways
2014
In this paper the calibration of a traffic microsimulation model based on speed-density relationships is presented. Hypothesis test was applied in the calibration process to measure the closeness between empirical data and simulation outputs and determine whether the difference between (observed and simulated) speed-density relationships was statistically significant. Statistical regressions between the variables of traffic flow were developed by using traffic data observed at the A22 Brenner Freeway, Italy. Similar relationships were obtained for a test freeway segment in uncongested conditions of traffic flow by using the Aimsun microscopic simulator; thus on field conditions were reprodu…
A Logic Fuzzy Model for Evaluation of the Railway Station’s Practice Capacity in Safety Operating Conditions
2013
Abstract The practice capacity of a railway junction depends, in addition to the effective operation’s conditions, by the potential risk factors related to the design plan of the railway station. With the aim of an approach based on the “fuzzy sets” it is possible to determine the numeric value of the practice capacity by the logic - qualitative relations between the features of the railway junction and the potential risk factors. This methodology permits to try out the absolute value of a suitable vector β, (less then the unit) for the utilization of the theoretic capacity in conditions of maximum reliability of the system related to the aspect of safety (technique “fail safe”).
L'espace-temps du TGV Rhin-Rhône. Quatre images de l'évolution de l'accessibilité ferroviaire.
2011
National audience; L'évolution du transport ferroviaire de voyageur est marquée par la constitution, depuis les années 1980, d'un réseau de Lignes à Grande Vitesse (LGV) ; les gains de temps sont en général, la principale justification de la construction de ces lignes ferroviaires nouvelles. La LGV Rhin-Rhône, conçue dans une dimension européenne entre territoire rhénan et arc méditerranéen, sera la prochaine infrastructure de ce type inaugurée (en décembre 2011). Les différents acteurs du TGV Rhin-Rhône sont attentifs à l'effet d'image du TGV et à l'amélioration présupposée de l'accessibilité que celui-ci va permettre. Cette amélioration est généralement argumentée à l'aide d'une valeur ch…
Nuevos caminos, territorio y paisaje en la Comarca de la Costera (Valencia). La mirada de los viajeros
2019
Por sus condiciones físicas, el valle de la Costera ha sido históricamente un lugar de paso obligado en el itinerario que, desde la llanura litoral valenciana, se dirige al sur y al centro peninsular. A finales del siglo XVIII se construye una moderna carretera y a mediados del XIX entra en servicio el ferrocarril entre Madrid y Valencia. En este trabajo analizamos la relación que se establece entre los caminos y el paisaje, y cómo esta se ha reflejado en los escritos que los viajeros que, entre finales del siglo XVIII y a lo largo de todo el siglo XIX, recorrieron por carretera y ferrocarril el valle de la Costera. Sus relatos integran estas modernas obras públicas con la visión secuencial…
Tecniche esecutive e controllo di qualità dei lavori in terra-calce
2010
Sebbene si tratti di una tecnica largamente sperimentata da diversi anni, ormai, e sviluppata per impieghi differenti che vanno dalla realizzazione di rilevati (stradali, ferroviari ed aeroportuali) alla formazione di strati di sottofondazione ed anche di fondazione delle pavimentazioni, la stabilizzazione con calce (o con calce e cemento), per essere applicata secondo le attuali regole dell’arte, richiede: · conoscenze tecniche comprovate negli studi di progetto delle miscele e nell’adeguamento della composizione delle stesse, in corso d’opera, in relazione alla variabilità dei fattori di cantiere (contenuto naturale d’acqua dei terreni, condizioni climatiche, dispersioni di dosaggio); · m…
STRATEGIE E CRITERI PROGETTUALI PER LA CONVERSIONE DI LINEE FERROVIARIE DISMESSE IN PERCORSI VERDI
2009
Il progressivo incremento della mobilità privata, verificatosi a partire dalla seconda metà del secolo scorso nei Paesi occidentali, e in particolare in Italia, ha determinato la chiusura al traffico di molte linee ferroviarie secondarie ormai scarsamente utilizzate e, dunque, poco remunerative per gli Enti proprietari e/o gestori. Il patrimonio viario dismesso trova oggi una possibile occasione di riqualificazione funzionale mediante la conversione delle linee ferrate in percorsi verdi (greenways) dedicati alla cosiddetta “mobilità dolce” di tipo ciclopedonale; ciò in ragione delle seguenti caratteristiche: i) separazione del sedime ferroviario dalla rete stradale ordinaria; ii) ridotto nu…
Heat capacity and thermal conductivity of multiferroics Bi1-xPrxFeO3
2019
The heat capacity and thermal conductivity of multiferroics Bi1–xPrxFeO3 (0 ≤ x ≤ 0.50) has been studied in the temperature range of 130–800 K. A slight substitution of praseodymium for bismuth is found to lead to a noticeable shift of the antiferromagnetic phase transition temperature whilst the heat capacity increases. The temperature dependences of the heat capacity and thermal conductivity exhibit additional anomalies during phase transitions. The experimental results suggest that the excess heat capacity can be attributed to the Schottky effect for three-level states. The basic mechanisms of the heat transfer of phonons are highlighted and the dependence of the mean free path on temper…