2,969 research outputs found
Applicazione di cementi fotocatalitici nelle opere di ingegneria civile
No full textNell’ambito della realizzazione di opere di ingegneria civile, quali edifici, reti
stradali in un contesto di tessuto connettivo urbano e non, l’impiego di cementi
fotocatalitici si colloca nel contesto attuale in cui è necessario coniugare
esigenze di valorizzazione del patrimonio esistente e di nuova edificazione con
le problematiche derivanti dall’inquinamento e di durabilità anche estetica.
Attraverso il processo fotocatalitico si è in grado di ridurre le concentrazioni di
inquinanti fotochimici in aria, mantenere le superfici pulite, bianche nonché
attive nella cattura e nello smaltimento di composti sotto forma di sali dilavati.
Di qui la scelta di abbinare alle consuete caratteristiche di impiego di un
cemento tradizionale le proprietà derivanti dal processo ossidativo
fotocatalitico, nel sincretistico approccio dell’impiego di cementi additivati con
TiO2.
Le possibili applicazioni comprendono numerose opere di ingegneria civile. Le
realizzazioni su cui si è indagato hanno coinvolto la messa a punto, dapprima, di
miscele di calcestruzzo drenante con cemento fotocatalitico, con aggregati
naturali e/o riciclati, per pavimentazioni stradali e la realizzazione di provini per
lo studio in laboratorio di fotocatalisi. Si è quindi proceduto a studiare
applicazioni in campo prova di calcestruzzo drenante e calcestruzzo drenante
fotocatalitico, di materiali fotocatalitici, tra cui un rasante e pitture, per
l’applicazione su superfici in ambiente outdoor ed indoor, quali su pareti di una
galleria stradale, di prodotti fotocatalitici per la applicazione a freddo su
pavimentazione, in particolare, di tipo autostradale.
Per quanto concerne la messa a punto delle miscele, il calcestruzzo drenante è
stato oggetto di studio in laboratorio calcestruzzi per il raggiungimento di
adeguate proprietà meccaniche ed idrauliche di permeabilità, nonché sono
state analizzate le proprietà in termini di abbattimento di inquinanti organici ed
inorganici, attraverso prove in modalità plug-flow, seguendo la attuale
normativa italiana aggiungendo tuttavia prove realizzate in modalità batch,
proponendo un modello per la caratterizzazione dei materiali e dei campioni
provenienti da opere realizzate con cementi fotocatalitici attraverso parametri
cinetici e di adsorbimento. Sono stati condotti studi sull’analisi per immagini,
approfondendo le indagini tramite scansioni in 2D e 3D, dimostrandone l’utilità
di impiego.
Relativamente agli studi su grande scala, sono state progettate e verificate
metodologie di lavoro atte a monitorare, isolare, indagare i parametri ritenuti
fondamentali nello studio di applicazioni di questo tipo. Si presentano i risultati
di realizzazioni e monitoraggio relativi ad una pavimentazione realizzata in
calcestruzzo drenante fotocatalitico, rivestimenti per gallerie, applicazione di
prodotti su pavimentazione autostradale
Removal of volatile organic compounds by advanced oxidation process: Performance of a plasma induced oxidation.
No full textPHOTOCHEMICAL POTENTIAL OF TITANIA PAINTING AT A HIGHWAY TUNNEL PORTAL. COMPARISON WITH THE CONDITIONS MEASURED ON SITE
No full textThe aim of this study is to evaluate the photoactivity of a commercial TiO2 coating at a highway tunnel, illuminated by UV-A lamps
Performance of a plasma induced oxidation on the removal of indoor volatile organic compounds
No full textThere is much interest in developing new technologies in order to improve indoor air quality. In this study non-thermal plasma (DC negative corona discharge) was explored as an innovative process for indoor air purification. Lab-scale test for Volatile Organic Compounds (VOCs) removal in an enclosed chamber, including a first-stage electrostatic precipitator (ESP) and UVA lamp, were executed for simultaneous removal of gaseous and particulate contaminants. Measurements of the temporal variation of the VOC concentration were employed for evaluating the rate removal. The ozone generation rate was noticeably decreased when the UVA lamp was operating. It is believed that additional studies are needed in the area of ozone enhanced oxidation with the aim to identify reaction products, allowing a better understanding of the degradation pathway of VOC in a non-thermal plasma
Photocatalytic action of water-based TiO2 paint inside a highway tunnel
No full textEuropean Symposium on Photocatalysis. CITE' MONDIALE
BORDEAUX - FRANC
Durability of NO Oxidation Effectiveness of Pavement Surfaces Treated with Photocatalytic Titanium Dioxide
No full textNowadays, photocatalysis has demonstrated to be a reliable solution in order to purify the atmosphere from the pollutants originated by vehicular traffic. Owing to the primary importance of this problem, the potential of innovative photocatalytic techniques, dealing with the immobilization of titanium dioxide TiO2 on the surface of the asphalt pavement, has been investigated. In particular, three different products, two bituminous emulsions and a cement mortar, were applied on the right lane and on the emergency lane of a highway section in Italy. The effectiveness of the photocatalytic treatments and its evolution with time were evaluated on cores taken after 1, 17, 46, 88, 218, and 527 days from the application of the products. Two tests were carried out on the cores: The NO degradation was evaluated through continuous flow tests, and the size of the treated areas was quantified by means of digital image analysis methods. The research showed interesting results, as all the techniques, in particular the bituminous emulsion-based products, proved to have a good effectiveness in air de-polluting, even if a decay of performance was noted, depending of traffic and weather conditions
Airborne Pollutant inside a Highway Tunnel Coated with a Photocatalytic Mortar
No full textAir pollution measurements were carried out at the Cavallo highway tunnel in Ancona, Italy. The tunnel is used daily by an average of 20,000 vehicles, of which 25% are gasoline fueled passenger cars, 25% diesel cars, and 50% trucks. Tunnel air concentrations of carbon dioxide, carbon monoxide, volatiles organic compounds (VOC), aromatic hydrocarbons and Nitrogen Oxides (NOx) are presented. An integrated sampling-analysis strategy has been implemented in order to get evidence on photocatalytic processes involved inside a highway tunnel freshly coated with mortar containing photocatalytic TiO2. In situ measurements, rather than laboratory material testing, has offered an efficient way for evaluating the occurrence of photocatalytic reactions, in spite of the presence of many conflicting meteorological and traffic parameters. The CO2 level inside the tunnel after the photocatalytic mortar treatment resulted initially 22% lower than before treatment but it reduced to a 14% within 6 months. The consistent decreases of acetates, nitrites, and sulphates, together with the sensible increase of oxalates observed on carbon adsorbing panels, point to the occurrence of oxidative reactions occurring inside the coated tunnel. Further study is required to elucidate the effect of NOx adsorption, in order to be able to make predictions of the time-dependence on the de-polluting effect, or how the mortar is influenced by the relative humidity, as well as its composition and exposure history
Preparation and characterization of an electrospun PLA-cyclodextrins composite for simultaneous high-efficiency PM and VOC removal
No full textElectrospinning is known to be a facile and effective technique to fabricate fibers of a controlled diameter-distribution. Among a multitude of polymers available for the purpose, the attention should be addressed to the environmentally compatible ones, with a special focus on sustainability. Polylactic acid (PLA) is a widespread, non-toxic polymer, originating from renewable sources and it can degrade into innocuous products. While the production of fibrous membranes is attractive for airborne particles filtration applications, their impact on the removal of gaseous compounds is generally neglected. In this study, electrospun PLA-based nanofibers were functionalized with cyclodextrins, because of their characteristic hydrophobic central cavity and a hydrophilic outer surface, in order to provide adsorptive properties to the composite. The aim of this work is to investigate a hybrid composite, from renewable sources, for the combined filtration of particulate matter (PM) and adsorption of volatile organic compounds (VOCs). Results show how their inclusion into the polymer strongly affects the fiber morphology, while their attachment onto the fiber surface only positively affects the filtration efficiency
An assessment of the impact of possible CAP reform scenarios on Romanian agriculture
No full textUsing a simplified model, with key-variable the prices of two different possible scenarios of CAP reform after 2013 (moderate and radical), this paper present a comparison between the price effects of implementation of each reform scenario at 2015 horizon on Romanian agriculture. This short analysis shows that, under the presented hypotheses, the net welfare effect, due to the price changes, for the selected products, is positive in both reform scenarios, yet greater in the case of the radical reform. Integrated in the large context of Romanian development, it seems that the influence of CAP reform upon agriculture and rural areas will be most likely a gradual one: an interpenetration between the two scenarios is foreseeable, starting with the moderate reform that will dominate the period around 2013, the reform measures acquiring a more radical character afterwards.CAP reform, Romania, welfare effects, Agricultural and Food Policy,
Rich, Sturmian, and trapezoidal words
No full textIn this paper we explore various interconnections between rich words, Sturmian words, and trapezoidal words. Rich words, first introduced by the second and third authors together with J. Justin and S. Widmer, constitute a new class of finite and infinite words characterized by having the maximal number of palindromic factors. Every finite Sturmian word is rich, but not conversely. Trapezoidal words were first introduced by the first author in studying the behavior of the subword complexity of finite Sturmian words. Unfortunately this property does not characterize finite Sturmian words. In this note we show that the only trapezoidal palindromes are Sturmian. More generally we show that Sturmian palindromes can be characterized either in terms of their subword complexity (the trapezoidal property) or in terms of their palindromic complexity. We also obtain a similar characterization of rich palindromes in terms of a relation between palindromic complexity and subword complexity
- …
