Search results for "Density"
showing 10 items of 4402 documents
Syntheses, Structures, and Magnetic Properties of Copper( II ) Complexes with 1,3‐[Bis(2‐pyridylmethyl)amino]benzene (1,3‐tpbd) as Ligand
2004
The dinuclear copper(II) complexes {[Cu2(1,3-tpbd)(H2O)(OAc)2](ClO4)2}0.23{[Cu2(1,3-tpbd)(H2O)2(OAc)](ClO4)3}0.77·0.77H2O (1), [Cu2(1,3-tpbd)(H2O)2(OAc)2](ClO4)2·2H2O (2), and the tetranuclear copper(II) complex [Cu4(1,3-tpbd)2(H2O)2(SO4)4]·8H2O (3) {1,3-tpbd = 1,3-bis[bis(2-pyridylmethyl)amino]benzene} were synthesised and structurally characterised by X-ray diffraction. Variable-temperature (2.0−290 K) magnetic susceptibility measurements on these complexes as well as on the dinuclear copper(II) complex [Cu2(1,3-tpbd)(H2O)2(ClO4)3]ClO4 (4) (whose structure was published earlier) were performed. In contrast to 2 and 3, significant ferromagnetic coupling with J = +9.3 cm−1 was observed for …
INFLUENCE OF POSIDONIA OCEANICA MEADOW DENSITY ON FLOW RESISTANCE IN SHALLOW WATERS
2008
Aquatic vegetation considerably affects circulation in water bodies with influence increasing as the depth decreases. On the other hand, increasing use of mathematical circulation models for management of coastal sea waters, lagoons and marshes requires determination of such effects and in particular of flow resistance. A typical plant of inshore sandy beds, less than 40 m deep, in the Mediterranean Sea is Posidonia oceanica, which is constituted by a tuft of very thin and flexible ribbon-like leaves about 1 cm wide and up to 1.5 m long. This plant forms meadows with areal density usually ranging between 500 and 1000 plants/m2. Because of its characteristics, Posidonia oceanica constitutes …
Planktothrix rubescens in freshwater reservoirs: remote sensing potentiality for mapping cell density
2012
Planktothrix rubescens is sadly famous for producing microcystins (MCs), which are powerful hepatotoxins. During the winter 2005/06, P. rubescens has been found in the Pozzillo, Nicoletti, Prizzi and Garcia reservoirs, Sicily; in 2008 it was also detected in SS. Trinita di Delia and Castello reservoirs. Indeed, during periods of low shortwave irradiance such as winter, when light weakly penetrates water column and the water cools, P. rubescens filaments float up to the surface, forming red-colored blooms. Ancillary meteorological measurements highlighted low air temperatures between two frosts in December 2007 and February 2008, with a simultaneous reduction in the incoming total solar radi…
Calibration of Speed-Density Relationships for Freeways in Aimsun
2014
The first application of a calibration methodology which uses speed-density relationships in the microsimulation calibration process is described in this article. Traffic patterns were implemented developing speed-density relationships for empirical and simulated data. For empirical relationships reference was made to traffic data observed at A22 Freeway (Italy). Aimsun microscopic traffic simulator software was then used to obtain analogous relationships for a test freeway segment under uncongested traffic conditions. Thus on field conditions were reproduced varying some calibration parameters until a good matching between field and simulation was achieved. The closeness between empirical …
UNA PROCEDURA AUTOMATIZZATA PER LA DETERMINAZIONE DELLE CARATTERISTICHE MICROSTRUTTURALI DELLE SABBIE MEDIANTE ANALISI DI IMMAGINI DI SEZIONI SOTTILI
2012
È ben noto che il comportamento meccanico microscopico delle sabbie - e in generale dei terreni granulari - trae origine dalle loro caratteristiche microstrutturali, quali, per esempio, il numero di coordinazione dei singoli grani, l’indice di contatto intergranulare (grain contact ratio) e l’indice di addensamento dei grani (packing density index). Appare, quindi, di notevole importanza la determinazione degli indici predetti con alto grado di affidabilità e di ripetibilità. Lo studio dell’assetto dei contatti intergranulari e il calcolo degli indici che lo caratterizzano, viene condotta comunemente su immagini piane dell’insieme di grani mediante esame visuale e restituzione grafica assis…
Sine cura. Verso il ri-ciclo dell'architettura del secondo Novecento
2019
Gli argomenti discussi nel saggio interrogano il destino che il Codice dei Beni Culturali (2004- 2011) determina per le opere del secondo Novecento. Nella costruzione del futuro di questi manufatti, che per funzione, tecnologia e cicli d’uso sono spesso segnati dall’obsolescenza e dall’abbandono, le ambiguità e le incongruenze delle attuali procedure legislative sollecitano profondamente il ruolo culturale delle esperienze di ricerca che usano metodologie meta progettuali. Il confronto fra alcuni casi italiani ed altri europei rimarca il ruolo del progetto nella costruzione di una prospettiva di tutela trasformativa per il costruito del secondo Novecento. Nel quadro di azione marcato dall’o…
Human Behavior and Urban Open Spaces in Hyper-Dense Areas: The Case of Dhiesheh Refugee Camp-Palestine
2010
Most of the world cities have hyperdense areas within its borders. Hyperdensity can appear in an informal settlement, in a slum area, in an old core, in a city center, or in a camp as in the case of Palestinian refugee camps. Hyperdensity conditions are capable to produce plenty of problems and questions related to the built up environment, quality of life, and people needs. This dissertation is based on exploring the combination between the physical form of urban open space and human behavior to investigate people's needs in urban open spaces of a hyperdense environment. The focus will be on Dheisheh refugee camp within Bethlehem city borders in the West Bank. The research is based on qual…
Amorphous semiconducting passive film-electrolyte junctions revisited. The influence of a non homogeneous density of state on the differential admitt…
2006
Abstract An analysis of the electronic properties of amorphous semiconductor-electrolyte junction is reported for passive films grown on Nb in alkaline solution and in a large range of thickness (~20nm ÷ ~250nm). A modelling of electronic density of state (DOS) has been carried out by fitting EIS spectra, at different potentials and in a range of frequencies (0.1 Hz ≤ f ≤100 kHz), and differential admittance (DA) data of a-Nb 2 O 5 /El interface. The fitting of EIS and DA curves was performed by using the theory of amorphous semiconductor Schottky barrier and a non-homogeneous DOS distribution.
Reverse electrodialysis with saline waters and concentrated brines: A laboratory investigation towards technology scale-up
2015
Abstract The use of concentrated brines and brackish water as feed solutions in reverse electrodialysis represents a valuable alternative to the use of river/sea water, allowing the enhancement of power output through the increase of driving force and reduction of internal stack resistance. Apart from a number of theoretical works, very few experimental investigations have been performed so far to explore this possibility. In the present work, two RED units of different size were tested using artificial saline solutions. The effects of feed concentration, temperature and flowrate on process performance parameters were analysed, adopting two different sets of membranes. These experiments all…
Experiments and modelling for determining the Limiting Current Density in Electrodialysis units
2018
In the present work, in order to explore such issues on the LCD identification, we performed in-situ measurements with ED units, assessing the influence of operating conditions and validating a purposely implemented process simulator, which was then used for further investigation