2,767 research outputs found
Metodologie innovative per il supporto alla progettazione e all’analisi delle prestazioni di impianti ad energia solare a concentrazione ed eolici off-shore utilizzando immagini satellitari ottiche e SAR
In questo lavoro presentiamo delle nuove metodologie, sviluppate nell’ambito del progetto SATENERG
(Servizi sATellitari per le ENergie Rinnovabili di nuova Generazione) finanziato dall’Agenzia
Spaziale Italiana, sia per il supporto alla progettazione/pianificazione che per il monitoraggio
quasi in tempo reale e l’analisi delle prestazioni degli impianti ad energia rinnovabile di nuova
generazione (CSP, CPV ed eolici off-shore) utilizzando immagini satellitari.
In particolare per quanto riguarda gli impianti solari a concentrazione (CSP e CPV), abbiamo
sviluppato un metodo per ricavare l’irradianza solare incidente al suolo (in particolare la sua
componente diretta normale rispetto ai raggi solari, fondamentale per questo tipo di impianti) da
immagini ottiche satellitari. Ciò, unito ad un modello di funzionamento di tali impianti e degli
inverter, ci ha resi in grado di poter sviluppare un servizio di supporto nella progettazione e pianificazione
di nuove costruzioni di impianti CSP e CPV (analizzando serie storiche di dati satellitari)
ed anche un servizio di monitoraggio e analisi delle prestazioni per quelli già esistenti (usando
invece immagini satellitari quasi in tempo reale).
In maniera simile, usando immagini SAR (Synthetic Aperture Radar), abbiamo sviluppato un metodo
per ricavare l’intensità e la direzione del vento in aree marine da remoto che ci ha permesso,
utilizzando anche un modello di impianto eolico off-shore (turbina e inverter), di sviluppare sia
un servizio di supporto alla progettazione/pianificazione che un servizio di monitoraggio quasi in
tempo reale della produzione di un impianto eolico off-shore.
Le prime applicazioni di queste nuove metodologie hanno già portato ad avere ottimi risultati in
vari casi di prova sia per quanto concerne il monitoraggio dell’irradianza diretta su piano normale,
in cui l’irradianza misurata e quella ricavata da dato satellitare non si sono discostate più del 10%, sia per quanto riguarda il calcolo dell’intensità e direzione del vento da immagini SAR, in cui l’errore
rispetto al dato misurato è rimasto al di sotto del 15%, fornendo quindi una buona base per il
monitoraggio della energia AC prodotta dagli impianti.In this work we present new methodologies aimed to support both planning and near-real-time
monitoring of new generation solar and wind energy plants (CSP, CPV and wind off-shore) using
satellite imagery. Such methodologies are currently being developed in the scope of SATENERG, a
project funded by ASI (Italian Space Agency).
In particular, for what concerns the concentrating solar energy plants (CSP and CPV) we developed
a method to calculate solar irradiance at ground (and its direct normal component, that has
primary importance in this type of plants) starting from satellite optical images. Then, using also
detailed opto-electronic models of the plants and inverters, we are able to calculate the producible
energy, which can be used to support either the design of potential plants (using historical series
of satellite images) or the monitoring and performance analysis of existing plants (using near-real-
time satellite imagery). Producible energy and other interesting parameters, like production
efficiency, return on investment etc., are delivered through dedicated web services.
In a similar way, we developed also a method to calculate the intensity and the direction of off-shore
wind from satellite SAR (Synthetic Aperture Radar) images that permitted us, together with
detailed models of wind turbine and inverters, to develop a new service in support to both planning
and near-real-time monitoring activities of off-shore wind plants.
The first applications of these methods gave successful results in several test cases: we obtained
a maximum error of 10% for satellite retrieved direct normal solar irradiance and a maximum
error of 15% for wind direction and intensity calculated from SAR images (with respect to in-situ
measured data)
New Data on Animal Exploitation at Shahr-i Sokhta (Iran): Preliminary Results from the Analysis of Animal Remains Found in Area 33
Gli strumenti in materia dura di origine animale provenienti da Shahr-i Sokhta: analisi preliminare
A method for characterizing the stability of light sources
We describe a method for measuring small fluctuations in the intensity of a laser source with a resolution of 10⁻⁴. The current signal generated by a PIN diode is passed to a front-end electronics that discriminates the AC from the DC components, which are physically separated and propagated along circuit paths with different gains. The gain long the AC signal path is set one order of magnitude larger than that along the DC signal path in such a way to optimize the measurement dynamic range. We then derive the relative fluctuation signal by normalizing the input-referred AC signal component to its input-referred DC counterpart. In this way the fluctuation of the optical signal waveform relative to the mean power of the laser is obtained. A "Noise-Scattering-Pattern method" and a "Signal-Power-Spectrum method" are then used to analyze the intensity fluctuations from three different solid-state lasers. This is a powerful tool for the characterization of the intensity stability of lasers. Applications are discussed
Far-field spectral characterization of conical emission and filamentation in Kerr media
By use of an imaging spectrometer we map the far-field ()
spectra of 200 fs optical pulses that have undergone beam collapse and
filamentation in a Kerr medium. By studying the evolution of the spectra with
increasing input power and using a model based on stationary linear asymptotic
wave modes, we are able to trace a consistent model of optical beam collapse
high-lighting the interplay between conical emission, multiple pulse splitting
and other effects such as spatial chirp.Comment: 8 pages, 9 figure
Agronomic and Environmental Benefits of Cover Crops in Northern Italy
Cover crops have a number of benefits (reduction of nitrate leaching and of soil erosion, control of weed seed bank, increase of soil organic matter and increase of cash crop yield), but these were seldom quantified in cropping systems of Northern Italy. This experiment aimed to quantify some of these effects, by comparing cover crop species and their management techniques
The Diacylglycerol Acyltransferase 3 of Chlamydomonas reinhardtii Is a Disordered Protein Capable of Binding to Lipids Derived from Chloroplasts
Understanding triacylglycerol (TAG) metabolism is crucial for developing algae as a source of biodiesel. TAGs are the main reservoir of energy in most eukaryotes. The final, rate-limiting step in the formation of TAGs is catalyzed by 1,2-diacylglycerol acyltransferases (DGATs). In the green alga Chlamydomonas reinhardtii, DGAT3 is phylogenetically related to plant DGAT3 but unrelated to other DGATs from eukaryotes, such as DGAT1 and DGAT2. In this study, we described the conformational preferences and the lipid-binding features of the DGAT3 from C. reinhardtii. To characterize its conformational stability and structural features, we used several biophysical probes, namely, fluorescence, circular dichroism (CD), and differential scanning calorimetry (DSC). Our results showed that the protein was mainly disordered, containing a small population of folded conformations in a narrow pH range (pH 8 to 10). The conformational stability of the folded structure of DGAT3 was very low, as shown by urea or guanidinium denaturations. Thermal denaturation, followed by fluorescence or CD, as well as calorimetric denaturation, followed by DSC, did not yield any transition in the pH range where DGAT3 acquired a “native-like” conformation. Furthermore, we used two approaches to demonstrate the interaction of DGAT3 with lipid membranes at the pH at which it had acquired a “native-like” conformation. The first involved the measurement of anisotropy and fluorescence quenching of the protein. The second approach focused on examining possible modifications of the biophysical properties of lipids due to their interaction with DGAT3, through anisotropy measurements and leakage assays. Both methods produced consistent results, suggesting that DGAT3 preferentially interacted with negatively charged membranes. These results will allow the design of a more efficient and stable DGAT3, as well as an in-depth understanding of how the metabolism of TAGs is accomplished in C. reinhardtii
Genetic PTX3 deficiency and aspergillosis in stem-cell transplantation
BACKGROUND:
The soluble pattern-recognition receptor known as long pentraxin 3 (PTX3) has a nonredundant role in antifungal immunity. The contribution of single-nucleotide polymorphisms (SNPs) in PTX3 to the development of invasive aspergillosis is unknown.
METHODS:
We screened an initial cohort of 268 patients undergoing hematopoietic stem-cell transplantation (HSCT) and their donors for PTX3 SNPs modifying the risk of invasive aspergillosis. The analysis was also performed in a multicenter study involving 107 patients with invasive aspergillosis and 223 matched controls. The functional consequences of PTX3 SNPs were investigated in vitro and in lung specimens from transplant recipients.
RESULTS:
Receipt of a transplant from a donor with a homozygous haplotype (h2/h2) in PTX3 was associated with an increased risk of infection, in both the discovery study (cumulative incidence, 37% vs. 15%; adjusted hazard ratio, 3.08; P=0.003) and the confirmation study (adjusted odds ratio, 2.78; P=0.03), as well as with defective expression of PTX3. Functionally, PTX3 deficiency in h2/h2 neutrophils, presumably due to messenger RNA instability, led to impaired phagocytosis and clearance of the fungus.
CONCLUSIONS:
Genetic deficiency of PTX3 affects the antifungal capacity of neutrophils and may contribute to the risk of invasive aspergillosis in patients treated (Funded by the European Society of Clinical Microbiology and Infectious Diseases and others) .with HSCT.Supported by grants from the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) (to Dr. Carvalho); the German Ministry for Education and Science (03Z2JN21, to Dr. Kurzai); the European Commission (FP7-HEALTH-2009-260338, to Dr. Romani; FP7-HEALTH-2011-280873, to Dr. Mantovani), the European Research Council (ERC-2008-AdG-233417, to Dr. Mantovani; ERC-2011-AdG-293714, to Dr. Romani), Associazione Italiana per la Ricerca sul Cancro (99629, to Dr. Mantovani); and Fundacao para a Ciencia e Tecnologia, Portugal (SFRH/BPD/46292/2008, to Dr. Carvalho; SFRH/BD/65962/2009, to Dr. Cunha; and SFRH/BPD/70783/2010, to Dr. Almeida)
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
- …