1,721,377 research outputs found
"Cella a biocombustibile abiotica"
No full textCella a biocombustibile abiotica comprendente un comparto anodico comprendente una camera anodica, in cui detta camera anodica contiene una prima soluzione elettrolitica, comprendente una soluzione alcalina e un biocombustibile disperso in detta soluzione alcalina, e un elettrodo di camera anodica a contatto con la prima soluzione elettrolitica; un comparto catodico comprendente una camera catodica, in cui detta camera catodica contiene una seconda soluzione elettrolitica, comprendente un accettore di elettroni, e un elettrodo di camera catodica a contatto con detta seconda soluzione elettrolitica; e mezzi iono-selettivi predisposti per separare la camera anodica e la camera catodica ed essere in comunicazione di fluido con esse; impianto comprendente tale cella a biocombustibile abiotica e suo processo di funzionamento
Analisi preliminare dei principali metalli pesanti nel sedimento delle Lagune di Grado e Marano
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Numerical simulation of groundwater flow in Dar es Salaam Coastal Plain (Tanzania)
No full textThey are presented the results of a groundwater modeling study on the Coastal Aquifer of Dar es Salaam
(Tanzania). Dar es Salaam is one of the fastest-growing coastal cities in Sub-Saharan Africa, with with more than
4 million of inhabitants and a population growth rate of about 8 per cent per year. The city faces periodic water
shortages, due to the lack of an adequate water supply network. These two factors have determined, in the last ten
years, an increasing demand of groundwater exploitation, carried on by quite a number of private wells, which
have been drilled to satisfy human demand.
A steady-state three dimensional groundwater model has been set up by the MODFLOWcode, and calibrated with
the UCODE code for inverse modeling. The aim of the model was to carry out a characterization of groundwater
flow system in the Dar es Salaam Coastal Plain.
The inputs applied to the model included net recharge rate, calculated from time series of precipitation data
(1961-2012), estimations of average groundwater extraction, and estimations of groundwater recharge, coming
from zones, outside the area under study. Parametrization of the hydraulic conductivities was realized referring
to the main geological features of the study area, based on available literature data and information. Boundary
conditions were assigned based on hydrogeological boundaries. The conceptual model was defined in subsequent
steps, which added some hydrogeological features and excluded other ones. Calibration was performed with
UCODE 2014, using 76 measures of hydraulic head, taken in 2012 referred to the same season. Data were
weighted on the basis of the expected errors. Sensitivity analysis of data was performed during calibration, and
permitted to identify which parameters were possible to be estimated, and which data could support parameters
estimation. Calibration was evaluated based on statistical index, maps of error distribution and test of independence
of residuals. Further model analysis was performed after calibration, to test model performance under a range of
variations of input variables
Applicazione della tecnica autometallografica per lo studio di accumulo e disaccumulo del rame nei molluschi bivalvi eduli della specie Tapes philippinarum
No full textVariations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Caratteristiche, tipologie ed applicazioni delle celle a combustibile
No full textUna cella a combustibile è un dispositivo elettrochimico che, fino a quando viene rifornito di combustibile ed ossidante, converte energia chimica in energia elettrica e calore in maniera continua.
Dal punto di vista del funzionamento, le celle a combustibile si basano sulla reazione che caratterizza l’elettrolisi inversa dell’acqua ed analogamente alle batterie sono composte da due elettrodi separati da un elettrolita, ma a differenza di queste i reagenti sono forniti in continuazione da un sistema apposito, cosa che avvicina la cella a combustibile ad un motore e fa sì che essa non abbia bisogno di essere ricaricata periodicamente.ope
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