Search results for "effect"
showing 10 items of 9072 documents
A study of Type B uncertainties associated with the photoelectric effect in low-energy Monte Carlo simulations
2021
The goal of this manuscript is to estimate Type B uncertainties in absorbed-dose calculations arising from the different implementations in current state-of-the-art Monte Carlo codes of low-energy photon cross-sections (<200 keV). Monte Carlo simulations are carried out using three codes widely used in the low-energy domain: PENELOPE-2018, EGSnrc, and MCNP. Mass energy-absorption coefficients for water, air, graphite, and their respective ratios; absorbed dose; and photon-fluence spectra are considered. Benchmark simulations using similar cross-sections have been performed. The differences observed between these quantities when different cross-sections are considered are taken to be a go…
Experimental generalized quantum suppression law in Sylvester interferometers
2017
Photonic interference is a key quantum resource for optical quantum computation, and in particular for so-called boson sampling machines. In interferometers with certain symmetries, genuine multiphoton quantum interference effectively suppresses certain sets of events, as in the original Hong-Ou-Mandel effect. Recently, it was shown that some classical and semi-classical models could be ruled out by identifying such suppressions in Fourier interferometers. Here we propose a suppression law suitable for random-input experiments in multimode Sylvester interferometers, and verify it experimentally using 4- and 8-mode integrated interferometers. The observed suppression is stronger than what is…
Ecological and social impacts of photovoltaic solar power plants and optimization of their locations in northern Chile
2017
Large scale photovoltaic (PV) solar power plants are gaining popularity in Chile. Solar energy potential in northern Chile is one of the best worldwide and true deserts are considered ideal environments for solar power plant projects. Atacama Desert is one of the driest places on earth. Nevertheless, northern Chile is home for many endemic species with 40 different vegetation types. The thesis presents studies of ecological effects (I-II) and location optimization of PV solar power plants in northern Chile (III). For ecological impacts two types of PV solar power plant technologies were studied: fixed mount solar plant and solar- tracking mounts. Study units were placed below the mounts or …
Applying an operating model for the environmental risk assessment in Italian Sites of Community Importance (SCI) of the European Commission Habitats …
2013
The fast development of agro-biotechnologies asks for a harmonized approach in risk analysis of GMO's releases, where "risk analysis" entails the assessment, management and communication of risk. Risk assessment consists in the evaluation of the likelihood that a hazard occurs, associated with the presence of the receptor(s) in the receiving environment, and the determination of their potential degree of exposure to the hazard. The whole process has to be both science based and applied case by case, and it involves a very complicated procedure that needs to be transformed in an operational and standardized tool. Beginning in 2003, an expert group on behalf of the Italian Ministry of the Env…
Odonats del País Valencià: diversitat, factors implicats en la composició de les seues comunitats i respostes als senyals de risc durant la fase d'ou
2017
Libèl·lules i espiadimonis són els noms comuns emprats per a anomenar eixos insectes que tan familiars en resulten i que configuren l’ordre escollit per a la realització d’aquesta tesi doctoral: el dels odonats. D’entre les característiques taxonòmiques que el configuren com a grup, cal destacar dos trets diagnòstics: un de la fase adulta i l’altre de la fase larvària. Un és l’òrgan copulador dels mascles adults, el qual s’ubica en el segon segment abdominal; aquesta característica determina un comportament reproductor exclusiu: durant l’aparellament el mascle doblega l’abdomen per a poder arribar a l’orifici genital de la femella. L’altre tret és la modificació del llavi inferior de les la…
Kształcenie umiejętności efektywnego słuchania na lekcjach języka polskiego
2015
Celem niniejszego artykułu jest zweryfikowanie, w jaki sposób autorzy podręczników szkolnych proponują kształcić umiejętność słuchania na lekcjach języka polskiego. Autorka po omówieniu specyfiki słuchania w komunikacji interpersonalnej oraz szczegółowych sprawności percepcyjnych, wyznacza cele doskonalenia słuchowego odbioru w edukacji polonistycznej. Następnie przedstawia analizę zadań dydaktycznych sklasyfikowanych ze względu na rozwijaną sprawność percepcyjną. Artykuł kończy się ukazaniem modelu kształcenia umiejętności słuchania wyłaniającego się z wybranych podręczników szkolnych.
Predictive First-principles Modeling of a Photosynthetic Antenna Protein : The Fenna-Matthews-Olson Complex
2020
High efficiency of light harvesting in photosynthetic pigment-protein complexes is governed by evolutionary-perfected protein-assisted tuning of individual pigment properties and inter-pigment interactions. Due to the large number of spectrally overlapping pigments in a typical photosynthetic complex, experimental methods often fail to unambiguously identify individual chromophore properties. Here we report a first principles-based modeling protocol capable of predicting properties of pigments in protein environment to a high precision. The technique was applied to successfully uncover electronic properties of the Fenna-Matthews-Olson (FMO) pigment-protein complex. Each of the three subunit…
Sustainable urban transport policy in emerging countries – case study of Mexico
2015
Negatywne efekty zewnętrzne transportu stanowią bolączkę współczesnych miast, niekorzystnie oddziałując na procesy rozwoju społeczno-gospodarczego. Problemy te są widoczne nie tylko w krajach wysoko czy średnio rozwiniętych – w ogromnym stopniu borykają się z nimi wielomilionowe i wielkopowierzchniowe metropolie, które z kolei są charakterystyczne głównie dla krajów wschodzących, jak np. Chiny, Indie, Brazylia czy Meksyk. Celem artykułu jest przedstawienie wybranych aspektów polityki zrównoważonego rozwoju transportu w stolicy jednego z tych krajów – Meksyku. Autorka starała się również odpowiedzieć na pytanie, w jaki sposób specyficzne uwarunkowania lokalne o różnym charakterze determinują…
Competition between chain scission and branching formation in the processing of high-density polyethylene: effect of processing parameters and of sta…
2009
Two samples of high-density polyethylene with different molecular weight were processed in a batch mixer and the rheological and structural properties were investigated. In particular, the effect of different processing parameters and the eventual presence of different stabilizers were evaluated. Actually, two reactions may occur during processing: branching/crosslinking or chain scission. The results indicate that when the processing conditions promote a scarce mobility of the macromolecular chains (lower temperatures, lower mixing speed, and higher molecular weight), branching is more favored than chain scission. On increasing the mobility of the chain (higher temperature, higher mixing s…
On the effectiveness of different additives and concentrations on the re-building of the molecular structure of degraded polyethylene
2006
Mechanical recycling is an easy and economic way to re-use plastic waste as secondary materials, but, in general, their properties are worse with respect to the reclaimed materials and the virgin polymer. The aim of this work was to study the effect of concentration and reaction kinetics of two additives, an ethylene-co-glycidyl methacrylate (Lotader) and a hydroxylamine derivative (CGX), in the re-building of a degraded polyethylene. CGX is a nitroxyl radical generator able to form branching in polyolefins while the epoxy groups of Lotader can react with the functional groups present in the recycled polyethylene. The results indicate that the CGX has a higher reaction rate than Lotader, pr…