1,721,001 research outputs found
Foto-elettrodi di ossido di titanio nano-strutturato per la foto-elettrolisi dell'acqua
No full textIn questo Rapporto Tecnico viene presentato lo stato dell’arte relativo alla preparazione di foto-elettrodi nano-strutturati
di ossido di titanio per il processo di foto-elettrolisi dell’acqua.
Il processo di foto-elettrolisi permette di ottenere H2 ed O2 dall’acqua in maniera assolutamente pulita, essendo la forza
motrice del processo l’energia solare. Inoltre, l’utilizzo del TiO2 comporta anche un basso impatto economico, per via
del basso costo di tale materiale.
Il rapporto in questione analizza gli aspetti teorici e sperimentali della produzione del TiO2 sotto forma di nano-strutture
altamente organizzate, ideali per aumentare la performance di tali materiali all’interno di una cella foto-elettrochimica.
Tuttavia, essendo lo studio di queste nano-strutture ad un stadio iniziale, molti aspetti di questo processo devono essere
ottimizzati al fine di poter approdare ad un discorso di tipo industriale e di produzione di massa.In this technical report, it’s related a state-of-the-art of the production of high ordered titanium dioxide nanotubes for
the photo-electrolysis of water.
The photo-electrolysis process permits to obtain H2 and O2 by water in a clean way, being the solar energy the only
driving force. Besides, the use of TiO2 has a low economic impact for the low cost of this material.
This report analyzes the theoretical and experimental aspects of the production of high order TiO2 nanotube arrays,
able to increase the performance of this material inside a photo-electrochemical cell. Yet, being the studies about these
nano-structures at a starting stage, many aspects has to be optimized in order to plan a mass production
Ricerca e sviluppo di materiali e processi per la realizzazione di materiali anodici con prestazioni migliorate. Test elettrochimici su nanotubi di TiO2 ottenuti mediante ossidazione di un substrato in titanio
No full textIl presente rapporto descrive la caratterizzazione elettrochimica di anodi costituiti da nanotubi di ossido di titanio (TiO2) ottenuti mediante ossidazione di un substrato in titanio. Gli anodi sono stati investigati in semicelle Li/elettrolita liquido/TiO2 in termini di capacità, cicli di vita ed efficienza coulombica a differenti regimi di corrente
Ricerca e sviluppo di materiali e processi per la realizzazione di materiali anodici con prestazioni migliorate. Test elettrochimici su anodi compositi
No full textIl presente rapporto descrive la preparazione e la caratterizzazione elettrochimica di anodi che utilizzano TiO2 (ossido di titanio), in qualità di materiale attivo. L’ossido di titanio, preparato per via elettrochimica è stato confrontato con TiO2 preparato sia mediante tecnica laser (ENEA) che commerciale
Modelling static and dynamic behaviour of proton exchange membrane fuel cells on the basis of electro-chemical description
No full textStable TiO2 nanotube arrays with high UV photoconversion efficiency
No full textThis work is intended to define an optimal methodology for preparing highly ordered TiO2 nanotube arrays by a 60-V anodization in a glycol ethylene solution. In order to obtain a mechanically stable structure with a high UV photoconversion efficiency, it is necessary to carefully control the growth mechanism through the anodization process. For this reason, the nanotube arrays have to be formed upon a compact titanium dioxide layer with well-defined thickness. Besides, both the fluoride concentration and anodization time are strictly correlated, because elevated concentrations and/or a long anodization time produce unstable structure with low photoconversion efficiency. The best result in the terms of reproducibility has been obtained previously for a three-minute galvanostatic oxide growth on the pickled titanium sheet, and anodic growth in ethylene glycol solution containing 1 wt.% H2O and 0.20 wt.% NH4F for a period lower than 4.5 h. The UV photoconversion efficiency was measured and a maximum value of 28.3% has been obtained, which is the highest result in the literature. (C) 2009 Elsevier Ltd. All rights reserved
Titanium nanotubes stimulate osteoblast differentiation of stem cells from pulp and adipose tissue
Full text linkBACKGROUND:
Titanium is the gold standard among materials used for prosthetic devices because of its good mechanical and chemical properties. When exposed to oxygen, titanium becomes an oxide, anatase that is biocompatible and able to induce osseointegration.
MATERIALS AND METHODS:
IN THIS STUDY WE COMPARED THE EXPRESSION PROFILING OF STEM CELLS CULTIVATED ON TWO TYPES OF SURFACE: Pure titanium disk and nanotube titanium disk in order to detect if nanotube titanium instead (NTD) surface stimulates stem cells towards osteoblast differentiation.
RESULTS:
Stem cells cultivated on nanotube titanium disks showed the upregulation of bone-related genes RUNX2, FOSL1 and SPP1.
CONCLUSIONS:
Results demonstrated that nanotube titanium disk surface is more osteo-induced surface compared to titanium disk, promoting the differentiation of mesenchymal stem cells in osteoblasts
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
Variations 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
- …
