Search results for "Tecnologie"

On the effectiveness of spif process to re-form end-of-life components as compared to conventional forming approach

2021

Manufacturing processes have a significant impact on global energy consumptions. The recovery of materials and functions for the implementation of the Circular Economy principle needs to be focused on either, by utilizing new techniques or the rethinking of old processes to rework End-of-Life (EoL) components. Previous researches have shown Single Point Incremental Forming (SPIF) process as a good alternative for sheet metal EoL components reuse by their reshaping. In this article, the authors aim to study the effectiveness of the SPIF processes by comparing its reshaping performance with other, more conventional forming processes. An initial Deep Drawing (DD) process was performed to imita…

Material Substitution for Automotive Applications: A Comparative Life Cycle Analysis

2012

Lightweight materials have become an important strategy in the automotive industry to enable vehicle weight reduction and reduce fuel consumption. However, when developing specific strategies, the overall benefits of any material should be analyzed throughout its life cycle to comprehend energy/environmental differences that arise during its processing and its final use. A key example is aluminum which despite having great potential in the use phase requires large amounts of energy to process. This paper provides a comparison between aluminum and steel utilizing a life-cycle approach. This approach reveals the importance of incorporating a recycling strategy to leverage aluminum’s low-weigh…

Che imprevisti a Sunny Island! Un divertente ambiente interattivo di apprendimento.

2015

Il software è un innovativo Ambiente Interattivo di Apprendimento sviluppato con Powersim Studio 10 Premium e basato sul Libro intitolato "Che imprevisti a Sunny Island". L'utente, dopo aver letto il libro, avrà modo di approcciare ai principi del pensiero sistemico in modo estremamente pratico attraverso un ambiente di simulazione che, riprendendo gli avvenimenti della storia narrata nel libro, gli consentirà di assumere delle decisioni autonome rispetto a quelle prese dai protagonisti della storia e verificarne gli effetti sul sistema sociale considerato. Ciò permetterà all'utente, tra le altre cose, di comprendere la complessità dell'ambiente sociale descritto nel libro e la natura delle…

Influence of fluorine on the synthesis of anatase TiO2for photocatalytic partial oxidation: Are exposed facets the main actors?

2018

Anatase TiO2 samples were synthesized in the presence of different amounts of HF acid with the aim of understanding the effect of the presence of fluorine on the photocatalytic activity. It is well known that the presence of fluoride ions influences the photocatalytic performance by adsorption on the surface of TiO2 and that they are capping agents in the control of specific exposed facets. The samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, nitrogen adsorption–desorption measurements, scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis spectrophotometry, and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity was eva…

PHOTOCATALYTIC ACTIVITY OF TIO2 IN ITS POLYMORPHIC FORMS ANATASE, BROOKITE AND RUTILE

2012

Determination of the crystallinity of TiO2 photocatalysts

2018

Abstract This study reports a new simple method to determine the crystallinity of anatase and rutile TiO2 photocatalysts. The crystallinity degree of various anatase and rutile samples was estimated by XRD analysis from the ratio among the full width at half maximum intensities of the main diffraction peaks of anatase or rutile and the (111) peak of CaF2 as internal standard. The photocatalytic activity of selected powders was tested employing the photodegradation of 4-nitrophenol in aqueous solution as probe reaction. The results showed that the photoactivity of the investigated samples increased with increasing crystallinity and crystallite size.

Photoactivity of Nanostructured TiO2 Catalysts in Aqueous System and their Surface Acid-Base, Bulk and Textural Properties

2007

This work reports on the characterisation and determintion of the photocatalytic activity of some TiO2 catalysts prepared using TiCl4 as precursor. The samples, consisting of suspensions, dispersions or powders of nanonstructured anatase or rutile phases, were obtained in very mild conditions, i.e., by boiling the solution obtained after hydrolysis of TiCl4 at atmospheric pressure: it is worth noting that no calcination was necessary to obtain photoactive phases. The samples were characterised by X-ray diffraction (XRD), determination of the BET specific surface area (SSA), scanning electron microscopy (SEM) observations and diffuse reflectance spectroscopy (DRS). FT-IR spectroscopy was use…

Visible light photocatalytic activity of macro-mesoporous TiO2-CeO2inverse opals

2018

Macro-mesoporous TiO2 inverse opal materials were synthesized and they were tested as photocatalysts under visible light irradiation. The influence of cerium oxide addition towards the Rhodamine B (RhB) photodegradation activity was evaluated. Structural, textural, spectral and surface properties of the TiO2-CeO2 inverse opal nanocomposites were studied by XRD, XPS, SEM, TEM, N2 adsorption-desorption, Diffuse Reflectance UV–vis and Photoluminescence spectroscopies. Compared to commercial TiO2 anatase, the macro-mesoporous TiO2 inverse opal exhibited six times higher kinetic rate constant in the RhB degradation under visible light irradiation. The good photocatalytic activity was related to …

Turning lipophilic phthalocyanines/TiO2 composites into efficient photocatalysts for the conversion of CO2 into formic acid under UV–vis light irradi…

2014

Metal-free, Cu(II)- or Zn(II) tetrakis [4-(2,4-bis-(1,1-dimethylpropyl)phenoxy)]phthalocyanines loaded over TiO2 (anatase) proved to be active in the photoreduction of CO2 to formic acid (HCO2H) in water under UV-vis light. CuPc/TiO2 is catalyst of choice, allowing to reach a maximum yield of HCO2H, unequalled by any other similar catalytic systems. Because of their low environmental impact, low potential cost, and efficient power conversion, these multipurpose materials show promise in the setup of sustainable methods for CO2 valorization. (C) 2014 Elsevier B.V. All rights reserved.

Photoactivity of shape-controlled TiO2 in gas-solid regime under solar irradiation

2019

Abstract Differently shape-controlled anatase TiO2 materials were tested as photocatalysts under both simulated and natural solar irradiation. Their photocatalytic activity in 2-propanol and propene partial oxidation and in the complete mineralization of acetaldehyde appears to increase with decreasing the shape control of the TiO2 material. This insight seems to be related to the residual presence of the templating species (fluoride anions) employed during the preparation of the shape-controlled TiO2 materials. In fact, the calcination of the powders, leading to levelling of the fluoride ions content, but also to a remarkable surface area decrease, gave rise to an increase of photocatalyti…