Enhanced equivalent model algorithm for solar mirrors

The SolarPACES Reflectance Guideline provides an essential tool to obtain comparable reflectance measurements, but because of the lack of adequate commercial instrumentation, till now the exhaustive characterization of reflectance behaviour versus incidence ¿i and (half) acceptance angle ¿ is unachieved. An expert group in Task III has been working to outline some practicable solutions. The Equivalent Model Algorithm (EMA) was found quite promising: with few input data, EMA allows to predict any reflectance feature by computation. The recent availability of reliable reflectance measurements at oblique incidence made possible the refinement of EMA by analysing a representative set of commercial solar mirrors. This paper describes the new EMA for solar mirror, named EMA4SM, and reports its validation

Molecular states of polyacenes grown on noble metal surfaces

Here we present a combined photoemission (UPS), metastable deexcitation (MDS) and optical absorption (NEXAFS) at C K-edge study of molecular states of polyacenes grown on Ag(111) and Au(111), from submonolayer to multilayer thicknesses. We focus on the evolution of the HOMO and LUMO molecular states induced by the adsorption from submonolayer to monolayer thickness and we find a different redistribution of these states in the various systems formed at RT: while a strong redistribution of the molecular states takes place in Pn/Ag(111) and Tc/Ag(111) interface, a weaker interaction is indicated for Tc/Au(111)

Investigation into the Coupling of Micro Gas Turbines with CSP Technology: OMSoP Project☆

Abstract Solar power generation has been gaining worldwide increasing interest by virtue of its ability to meet both the growing energy needs and the increasing concerns on the carbon dioxide emissions. One of the most promising Concentrated Solar Power (CSP) technologies under development uses a parabolic dish to concentrate solar power into a focal point, raising thetemperature of a working fluid which is then used in a thermodynamic cycle to generate electricity. In the OMSoP project, funded by the European Commission, it is proposed to use a Brayton cycle in the form of a micro-gas turbine (MGT), which replaces the more conventional Stirling engine,with the aim of increasing the ratio of the electric power generated to the solar energy collected and improving the operability in relation to solar energy short time fluctuations. To achieve these objectives, research and development will be conducted in all aspects of the system leading to a full scale demonstrative plant to be located at the ENEA Casaccia Research Centre.The present work deals with the activities carried out so far by ENEA, which is principally involved in the development and experimental characterization of the dish component, and in the integration of the complete system, both in terms of modelling and realization

Redox-Active Ferrocene grafted on H-Terminated Si(111): Electrochemical Characterization of the Charge Transport Mechanism and Dynamics

Electroactive self-assembled monolayers (SAMs) bearing a ferrocene (Fc) redox couple were chemically assembled on H-terminated semiconducting degenerate-doped n-type Si(111) substrate. This allows to create a Si(111)|organic-spacer|Fc hybrid interface, where the ferrocene moiety is covalently immobilized on the silicon, via two alkyl molecular spacers of different length. Organic monolayer formation was probed by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) and X-ray photoelectron spectroscopy (XPS) measurements, which were also used to estimate thickness and surface assembled monolayer (SAM) surface coverage. Atomic force microscopy (AFM) measurements allowed to ascertain surface morphology and roughness. The single electron transfer process, between the ferrocene redox probe and the Si electrode surface, was probed by cyclic voltammetry (CV) measurements. CVs recorded at different scan rates, in the 10 to 500 mV s−1 range, allowed to determine peak-to-peak separation, half-wave potential, and charge-transfer rate constant (KET). The experimental findings suggest that the electron transfer is a one electron quasi-reversible process. The present demonstration of surface engineering of functional redox-active organometallic molecule can be efficient in the field of molecular electronics, surface-base redox chemistry, opto-electronic applications

New insights on the interaction between thiophene derivatives and Au surfaces: the case of 3,4-ethylenedioxythiophene and the relevant polymer.

The nature of the interface between electrogenerated poly(3,4-ethylenedioxythiophene) and the Au substrate is studied in detail. In particular, the adsorption of the relevant monomer, namely, 3,4-ethylenedioxythiophene, is investigated and compared with that of other thiophene derivatives. Different deposition procedures have been adopted: very thin films of the thiophene derivatives have been obtained through chemisorption processes from vapor and liquid phases, on Au polycrystalline substrates, Au nano particles possessing different size, and a Au(111) single crystal. Different techniques, operating both in situ and ex situ, have been employed for the characterization of these deposits, that is, X-ray photoemission and surface enhanced Raman spectroscopy. The results show that the poly(3,4-ethylenedioxythiophene)/metal interface is far from being simply constituted by unreacted molecules in contact with the substrate; rather, the formation of oligothiophene species and sulfur atoms at the interface has been ascertained

Establishing comprehensive oral assessments for children with safeguarding concerns.

The dental profession is well placed to contribute important information in child protection cases but no previous research has been reported that assesses the volume or impact of this information. Comprehensive oral assessment clinics were introduced and established as an integral part of comprehensive medical assessments for children with welfare concerns in Greater Glasgow and Clyde. An assessment protocol and standardised paperwork for comprehensive oral assessments were developed to enhance information sharing and patient access to appropriate care. Two cases are presented and discussed to demonstrate the value of dental input

A Quasi-Steady State Model of a Solar Parabolic Dish Micro Gas Turbine Demonstration Plant

In the framework of the European Optimised Microturbine Solar Power system (OMSoP) project, a novel energy system for solar electricity production was developed, based on the integration of the solar dish technology with Micro Gas Turbines (MGT). A pilot plant with a capacity of 5–7 kWe was realized and installed at the ENEA Casaccia site (Rome) and went under testing to validate the feasibility of the technology and improve the current design. The present work deals with the development of a quasi-state system model, built in the Engineering Equation Solver environment, composed of different modules that correspond to the main system components. The system model was used to define the optimal system parameters, to help the elaboration on an operational strategy to maximize the overall plant efficiency, and to guide the improvement of the single components in view of their optimised design. From the analysis it emerged that the system in design conditions is able to generate, in nominal conditions, 4.5 kWe instead of the expected 5 kWe due to the limitation of the stator current to 13 A, while maximum levels of 5.6 kW could be achieved by “overcharging” the high-speed generator up to 15 A and operating the MGT at the very high speed of 150 krpm. From the transient simulation of the demo system on an annual basis, the maximum average output power is 3.58 kWe. Regarding the cycle efficiency, the annual averaged value is about 17%, whereas the target value is 21%. The improvement of the generator only does not seem to significantly increase the power output on the annual basis (3.75 kWe vs. 3.58 kWe). Differently, the improvement of the solar dish, with the upgrade of the other system components, would significantly increase the system power output to around ~10 kWe

Influence of domestic and environmental weathering in the self-cleaning performance and durability of TiO2 photocatalytic coatings

Weathering of photocatalytic TiO2 coatings represents an important issue for the successful application of TiO2- based self-cleaning materials. Photocatalytic efficiency of the as-prepared materials is crucial for commercialization; however, changes in the coating performance due to weathering become a critical factor for practical applications. Moreover, chemical durability should be considered as weathering can promote the release of photocatalyst nanoparticles, which can pollute the environment and be hazardous for human health. In this study, two photocatalytic TiO2 coatings with different microstructures (namely compact and mesoporous) were exposed to chemical treatments to simulate domestic and environmental weathering. Results show that dense TiO2 coatings with a slow photocatalytic activity are suitable for domestic applications as minimum leaching of photoactive material was observed. Conversely, once exposed to chemical solutions commonly present in domestic environments, the initially highly active mesoporous TiO2 coatings showed a dramatic drop of the selfcleaning performance and a significant release of nanoparticles in the surrounding environment. It is expected that the results reported here will be of particular relevance for the construction sector, as the manuscript discloses important knowledge for the development of TiO2-based self-cleaning materials once exposed to indoor or outdoor environments

Role of gallium diffusion in the formation of a magnetically dead layer at the Y3Fe5O12/Gd3Ga5O12 epitaxial interface

We have clarified the origin of a magnetically dead interface layer formed in yttrium iron garnet (YIG) films grown at above 700 degrees C onto a gadolinium gallium garnet (GGG) substrate by means of laser molecular beam epitaxy. The diffusion-assisted formation of a Ga-rich region at the YIG/GGG interface is demonstrated by means of composition depth profiling performed by x-ray photoelectron spectroscopy, secondary ion mass spectroscopy, and x-ray and neutron reflectometry. Our finding is in sharp contrast to the earlier expressed assumption that Gd acts as a migrant element in the YIG/GGG system. We further correlate the presence of a Ga-rich transition layer with considerable quenching of ferromagnetic resonance and spin wave propagation in thin YIG films. Finally, we clarify the origin of the enigmatic low-density overlayer that is often observed in neutron and x-ray reflectometry studies of the YIG/GGG epitaxial system