APPLICATION OF GRAPHENE OXIDE IN CEMENTITIOUS COMPOSITES FOR CEMENT CONTENT REDUCTION

oai:ojs.journaluts.emnuvens.com.br:article/6Cement production is responsible for 5% of CO2 emissions worldwide. The concern about the pollution derived from the construction industry has brought attention to the need of developing more sustainable construction materials and processes. Admixtures based on nanometric graphene oxide have the potential to enhance mechanical properties and durability of cementitious composites. In this context, an experimental program was conducted to evaluate how the addition of graphene oxide may be used to reduce cement content in concretes, maintaining the same mechanical properties of conventional concretes (control matrices, with no graphene oxide additions). Kinetics of hydration of cement pastes was evaluated by isothermal calorimetry, phase evolution during hydration was determined by X-ray diffraction coupled with quantitative Rietveld analysis and mechanical properties were evaluated by compressive strength. Results indicate that graphene oxide additions provide a faster hydration rate until 24 h and generate a larger amount of C-S-H gel, increasing mechanical strength of the matrix. By the addition of graphene oxide dispersion (0.4% of solid content) at 0.02% by cement weight, cement content reductions of up to 15% may be achieved, maintaining the same compressive strength as the control matrices. From this research, a reduction in cement content to obtain more sustainable construction materials and processes may be achieved

Acquired Strabismus in Linear Scleroderma of the Face

Abstract is missing (Short communication

A Digital Process for Manufacturing Customized Trays for Dental-Whitening Treatments

This study presents an alternative process for designing and manufacturing customized trays for dental-whitening treatments. The process is based on a digitized approach consisting of three main stages: design of a reference model, its manufacturing by AM, and thermoforming of the tray. The aim of the study was to develop a high-performance tray, able to guarantee comfort, safety, and efficacy for whitening treatments. To evaluate the patient’s experience, some tests under real operating conditions were performed. Twenty people carried out a nighttime treatment of 14 days. Each patient was asked to assess the overall level of satisfaction and the comfort of the tray and its ability to retain the gel. Tooth whitening was also determined according to the VITAPAN scale. All patients involved in the study were satisfied and provided positive feedback about comfort and tightness of the tray. At the end of the treatment, 15 out of 20 patients achieved shade A1 on the VITAPAN scale. The mean improvement in color shades was about 7. These results confirmed the great potential of the proposed dental tray. Its use was proven to guarantee a high level of quality, flexibility, and customization of dental-whitening treatments, improving comfort, safety, and efficacy

Tecniche integrate di Remote Sensing e GIS a supporto della stima del potenziale fotovoltaico su tetti in aree urbane

Le ultime linee guida approvate dal Governo Italiano per sostenere finanziariamente il fotovoltaico (PV) e lo sviluppo della produzione di energia solare (Quarto e Quinto Conto Energia, Gennaio 2012 e succ.), al fine di evitare il consumo di suolo in aree agricole o naturali, comprendono indicazioni specifiche che rendono più vantaggiosa l’installazione d’impianti su tetti o superfici di copertura di edifici. In questo contesto diventa importante, per una adeguata attività di pianificazione e monitoraggio del PV, la mappatura estensiva delle superfici a disposizione, coincidenti con i tetti e l’accurata valutazione del loro potenziale fotovoltaico. Dal momento che tali coperture si trovano soprattutto nelle aree urbane o industriali, in cui fattori come eterogeneità tridimensionale, albedo, torbidità atmosferica ed ombreggiamenti reciproci influenzano in modo significativo l’irraggiamento solare locale, è necessario tenere conto adeguatamente di questi elementi mediante una mappatura GIS tridimensionale ed avanzati strumenti di modellazione, in modo da stimare efficacemente la radianza solare disponibile a livello dei tetti. La metodologia implementata, basata su tecniche di telerilevamento e GIS, ha permesso di valutare e mappare la radiazione solare globale su tutti i tetti presenti nel territorio del Comune di Avellino. Partendo da dati di tipo LIDAR, è stato ottenuto in primo luogo il DSM di tutta l’area di interesse (~ 42 Km2), quindi il modello tridimensionale di ogni edificio da cui sono stati derivati i parametri geometrici di tutte le coperture. Per tenere conto della trasparenza atmosferica e della percentuale di radiazione solare (diffusa/diretta) sulle superfici di interesse, sono stati utilizzati i dati e gli strumenti applicativi presenti sul sito web PVGIS, sviluppato dalla UE. L’elaborazione finale, basata sull’utilizzo di strumenti GIS anche di tipo open source, ha permesso di ottenere le mappe di radianza solare e di potenziale PV per tutti i tetti presenti nell’area di studio.The last guidelines approved by Italian government to financially support the solar Photovoltaic (PV) Energy production development (Fourth and Fifth feed-in-scheme, January 2012 and later), in order to avoid soil consumption in agricultural or naturals areas, include specific indications for more advantageously funding the installations exploiting roofs or covers surfaces. In this context it becomes important, for a suitable PV planning and monitoring, the extensive mapping of the available surfaces extent, usually corresponding to covers and properly assessing their quality in term of PV potential. Since the covers are mainly located in urban or industrial areas, whose 3D heterogeneity, albedo, atmospheric turbidity and casting shadows significantly influence the local solar irradiance, it is necessary to suitably account for these distributed factors by means of GIS mapping and advanced modeling tools in order to provide realistic estimates of solar available radiance at roofs level. The implemented methodology, based on remote sensing techniques, has allowed to estimate and map the global solar radiance over all the roofs within Avellino municipality. Starting from LIDAR data, DSM of the entire area of interest (~42 Km2) has been firstly obtained; then the 3D model of each building and related cover has been derived. To account for the atmospheric transparency and the related time-dependent diffuse/direct radiation percentage on the area, data and tools from EU PVGIS web application have been also used. The final processing to obtain the solar radiance maps has been carried out using specific software modules available within commercial and open-source GIS packages

Polarization preserving ultra fast optical shutter for quantum information processing

We present the realization of a ultra fast shutter for optical fields, which allows to preserve a generic polarization state, based on a self-stabilized interferometer. It exhibits high (or low) transmittivity when turned on (or inactive), while the fidelity of the polarization state is high. The shutter is realized through two beam displacing prisms and a longitudinal Pockels cell. This can represent a useful tool for controlling light-atom interfaces in quantum information processing.Comment: 4 pages, 6 figure

Cognitive Functions and Cognitive Reserve in Relation to Blood Pressure Components in a Population-Based Cohort Aged 53 to 94 Years

In 288 men and women from general population in a cross-sectional survey, all neuropsychological tests were negatively associated with age; memory and executive function were also positively related with education. The hypertensives (HT) were less efficient than the normotensives (NT) in the test of memory with interference at 10 sec (MI-10) (−33%, P = 0.03), clock drawing test (CLOX) (−28%, P < 0.01), and mini-mental state examination (MMSE) (−6%, P = 0.02). Lower MMSE, MI-10, and CLOX were predicted by higher systolic (odds ratio, OR, 0.97, P = 0.02; OR 0.98, P < 0.005; OR 0.95, P < 0.001) and higher pulse blood pressure (BP) (OR 0.97, P = 0.02; OR 0.97, P < 0.01; and 0.95, P < 0.0001). The cognitive reserve index (CRI) was 6% lower in the HT (P = 0.03) and was predicted by higher pulse BP (OR 0.82, P < 0.001). The BP vectors of lower MMSE, MI-10, and CLOX were directed towards higher values of systolic and diastolic BP, that of low CRI towards higher systolic and lower diastolic. The label of hypertension and higher values of systolic or pulse BP are associated to worse memory and executive functions. Higher diastolic BP, although insufficient to impair cognition, strengthens this association. CRI is predicted by higher systolic BP associated to lower diastolic BP

orthostatic hypotension does not increase cardiovascular risk in the elderly at a population level

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