Optimized TiO2 blocking layers for dye-sensitized solar cells (DSSC)

In recent years much attention has been paid to dye-sensitized solar cells due to their low cost and wide applicability. The modest efficiencies achieved by these devices are caused by several phenomena including electronic losses due to parasitic electronic reactions. One of the most common way to reduce the electronic losses is to introduce a compact layer of conductive material (blocking layer) between the transparent conductive substrate and the sensitized semiconductor film. Aim of this work was to asses the correlation between the most common deposition processes and the final properties of the blocking layers produced by them. The blocking layer of TiO2 was prepared on FTO glass using two of the most commonly used colloidal deposition processes: dip and spin coating. The results obtained with the conventional dip coating were compared with the ones coming from spin coating of two different solutions of TiCl4 (50 mM). These solutions were characterized in terms of viscosity, surface tension and contact angle. The spin coating parameters were optimized on the basis of these analysis. The influence of subsequent cycles of deposition (2,4,6) was also evaluated. The TiO2 films obtained were deeply characterized (AFM, SEM, UV-vis and electrochemical measurement) in order to assess the best conditions needed to obtain an efficient blocking layer (BL)

Morphological and electrochemical characterization of TiO2 blocking layers in Dye Sensitized Solar Cells

In recent years much attention has been paid to dye-sensitized solar cells due to their low cost and wide applicability. The modest efficiencies achieved by these devices are caused by several phenomena, including electronic losses due to parasitic electronic reactions. One of the most common way to reduce the electronic losses is to introduce a compact layer of conductive material (blocking layer) between the transparent conductive substrate and the sensitized semiconductor film. Aim of this work was to asses the correlation between the most common deposition processes (spin coating and dip coating) and the morphological and electrochemical properties of the blocking layers produced by them. The blocking layer of TiO2 was prepared on FTO glass, and the results obtained with the conventional dip coating were compared with the ones coming from spin coating of two different solutions of TiCl4 (50 mM). The TiO2 films obtained were deeply characterized in particular from the electrochemical point of view in order to assess the best conditions needed to obtain an efficient blocking layer. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used to understand the electrochemical behavior of the blocking layer (BL

Use of Sentinel-2 satellite imagery for forest site evaluation and forest harvesting detection

The access to Earth Observation data leaded researcher to a different point of view in the forest sector. Immediately tropical forest deforestation drawn the majority of interests (Perbet et al., 2019; Tang et al., 2019; Shimizu et al., 2017; Asner et al., 2009), heading to the development of many different tools for tropical forest monitoring. This study was focused on the application of satellite remote sensing data (derived from Sentinel-2) to two cardinal aspect for Italian forest. Since wood production plays a key role in developing a rural economy and stimulating the use of sustainable raw material, an increment of Douglas-fir plantation is desirable because of his great growth potential. Therefore, it was necessary to investigate good indices in order to assess the Douglas-fir land suitability and fertility indices. Empirical models were developed and validated using different sets of variables derived from remote sensing data and field survey. Models validation reached good results for Site Index ranging from 0.63 to 0.97 R2 and Current Annual Increment ranging from 0.50 to 0.98 R2. Furthermore, remote sensing data were applied to calibrate and validate different approaches for forest change detection. Knowing where and when forest harvests are done is crucial for correctly applying sustainable forest management and for controlling illegal logging. In this study was demonstrated that there are already tools developed in tropical forest that they could be applied to Italian forest. The best method was the basic one, which uses only summer images avoiding the seasonal noise problem in the time series but losing near-real time ability. If the temporal accuracy is essential the best method for removing time series seasonality resulted the harmonic model fitting, but further analyses are needed expanding the validation area in order to corroborate these results

Implementing a distributed mobile calculus using the IMC framework

In the last decade, many calculi for modelling distributed mobile code have been proposed. To assess their merits and encourage use, implementations of the calculi have often been proposed. These implementations usually consist of a limited part dealing with mechanisms that are specific of the proposed calculus and of a significantly larger part handling recurrent mechanisms that are common to many calculi. Nevertheless, also the "classic" parts are often re-implemented from scratch. In this paper we show how to implement a well established representative of the family of mobile calculi, the distributed [pi]-calculus, by using a Java middleware (called IMC - Implementing Mobile Calculi) where recurrent mechanisms of distributed and mobile systems are already implemented. By means of the case study, we illustrate a methodology to accelerate the development of prototype implementations while concentrating only on the features that are specific of the calculus under consideration and relying on the common framework for all the recurrent mechanisms like network connections, code mobility, name handling, etc

A multicenter study on reliability and validity of a new triage system: the Triage Emergency Method version 2

In Italy there are many triage guidelines and methods based on consensus. But, to our knowledge, there are few data on the reliability and predictive validity of triage systems adopted by Italian emergency departments. The Triage Emergency Method version 2 (TEM v2) is a new four-level in-hospital triage system. This paper presentes a before-and-after observational study performed using triage scenarios from June 2008 to September 2009 in 6 Italian emergency departments. Twelve nurses who received a 5-h training on TEM and a panel of experts on TEM assigned priority code to 66 scenarios. To test the inter-rater reliability among participants and the panel of experts (before and after the course), we used the weighted K statistic. We assessed the validity of TEM by calculating sensitivity, specificity and accuracy for predicting the reference standard's triage score. The TEM v2 showed good and very-good agreement among all 6 groups of nurses with a K range=0.61-1. Also, sensitivity, specificity and accuracy of nurses' triage rating for predicting the reference standard's triage code was good (accuracy range=78-90%). In this multicenter study, TEM v2 has a good inter-rater reliability for rating triage acuity among all groups of participating nurses, with a K value similar to the reference standard reliability (K=0.75). Thus, the Triage Emergency Method version 2 seems to be valid and accurate in predicting a reference standard rating

A Calculus of Bounded Capacities

Resource control has attracted increasing interest in foundational research on distributed systems. This paper focuses on space control and develops an analysis of space usage in the context of an ambient-like calculus with bounded capacities and weighed processes, where migration and activation require space. A type system complements the dynamics of the calculus by providing static guarantees that the intended capacity bounds are preserved throughout the computation

Structural operational semantics for stochastic and weighted transition systems

We introduce weighted GSOS, a general syntactic framework to specify well-behaved transition systems where transitions are equipped with weights coming from a commutative monoid. We prove that weighted bisimilarity is a congruence on systems defined by weighted GSOS specifications. We illustrate the flexibility of the framework by instantiating it to handle some special cases, most notably that of stochastic transition systems. Through examples we provide weighted-GSOS definitions for common stochastic operators in the literature

Multi-phase (Zr,Ti,Cr)B2solid solutions: Preparation, multi-scale microstructure, and local properties

Multi-phase ceramics based on ZrB2, TiB2 and doped with CrB2 and SiC were prepared by powder metallurgy and hot pressing to explore the possibility of obtaining multi-scale microstructures by super-saturation of complex (Zr,Ti,Cr)B2 solid solutions. Core–shell structures formed in TiB2 grains, whereas ZrB2 appeared to form a homogeneous solid solution with the other metals. Precipitation of nano-inclusions within both micron-sized borides was assessed by transmission electron microscopy and thermodynamics elucidated the preferential formation of boride inclusions due to the specific sintering atmosphere. In addition, atomic size factors explicated the precipitation of CrB2 nano-particles into ZrB2-rich grains and of ZrB2 nano-particles into TiB2-rich grains. The hardness of the constituent phases measured by nanoindentation ranged from 36 to 43 GPa

long term outcomes following drug eluting stent implantation in unprotected left main bifurcation lesions

Background The safety and efficacy of drug-eluting stents (DES) implantation in unprotected left main (LM) bifurcation lesions has yet to be determined. The aim of the present report was to evaluate the long-term outcome following implantation of DES in unprotected LM bifurcation lesions. Methods We identified 70 consecutive patients treated with DES in unprotected LM bifurcation lesions from April 2003 to January 2005. Of them, 42 patients were treated with sirolimus-eluting stent (SES) and 28 patients were treated with paclitaxel-eluting stent (PES). Results Stents to the left anterior descending and to the circumflex were implanted in 62 patients. During 1-year follow-up, 3 (4.3%) patients died of cardiac causes. One of them had myocardial infarction and adjudicated as possibly due to stent thrombosis. Angiographic follow-up was available in 80% of patients. The per lesion restenosis rate was 13.4% in the entire cohort, of which 10.7% occurred in lesions treated with SES and 16.1% in those treated with PES (P=0.58). All restenosis was focal and occurred in the lesions treated with a stent with stent size to post-procedural reference vessel diameter ratio <1.0 (17.6% vs 0, P=0.04). The per patient target lesion revascularization rate at 1 year was 17.1%. One year survival free from major adverse cardiac events was 77.1%. Conclusions Treatment of LM bifurcation lesions using DES is a safe and feasible way with a low one-year mortality. The need for revascularization in 17% of patients demands for improvement