Search results for "centre"
showing 10 items of 478 documents
Centre-pivot irrigation system design for uniform water application rate
2020
<p>In the last few decades, the use of centre-pivot irrigation systems has significantly increased, since it makes farming easier, is more efficient and less time-consuming compared to the other irrigation systems. Several studies have been focused on the hydraulics of the centre-pivot systems. Standard high-pressure impact sprinklers or low-pressure spray sprinklers or Low Energy Precision Application (LEPA) systems are generally mounted on the pipeline.</p><p>To ensure the uniformity of water application, the centre-pivot design requires increasing the flow rates along the lateral, because the sprinklers farther from the pivot move faster, and th…
Tres conferències sobre el Tirant lo Blanch a València (1912, 1919 i 1921)
2017
Com a fruit de l’esforç de recuperació de les principals obres literàries medievals que durant la segona meitat del segle XIX portaren a terme els protagonistes de la Renaixença, entre els anys 1912 i 1921 a la ciutat de València se celebraren tres conferències que tingueren com a tema principal el Tirant lo Blanch, i que contribuïren notablement a divulgar la novel·la de Martorell entre les classes socials més actives, des d’un punt de vista intel·lectual i cívic. Així, cal assenyalar que, per aquells anys, el Tirant ja havia adquirit un gran simbolisme cultural i patriòtic per als valencians; i que, ben significativament, aquelles ponències –que varen ser organitzades per les entitats Lo …
Changements de stratégie temporelle durant des tâches motrices complexes chez des sujets âgés sains
2017
International audience; Cette étude a permis d’analyser des points temporels clefs de la réalisation de mouvements impliquant l’ensemble du corps (Whole Body Reaching movements - WBR). Lors de ce mouvement, le sujet déplace son Centre de Masse (CdM) vers l’avant pour l’atteindre une cible. Ceci implique une inclinaison du tronc créant des modifications posturales et un risque de chute. Ces différentes considérations nous ont poussées à étudier une population de sujets âgés (SA) en comparaison à des sujets jeunes (SJ). Nous avons analysé des points stratégiques au cours de la tâche, dont deux plus particulièrement. La décomposition axiale de la vitesse du CdM en deux composantes (Verticale-V…
Centri storici meridionali: verso quale futuro?
2020
Il contributo prende le mosse da una domanda di fondo, e cioè se i centri storici delle grandi e medie città meridionali, interessati da processi di recupero e di riqualificazione, possano sfuggire a un destino settoriale basato prevalentemente sull’eccellenza del patrimonio, sul turismo e sulle attività culturali o possano continuare a svolgere il ruolo di strutture urbane vitali, dotate di un mix di attività ordinarie e di funzioni, prima fra tutte, quella residenziale. L’intervento sui centri storici richiede un’ottica multidisciplinare integrata, che dalla visione complessiva dei problemi faccia discendere strategie per la conservazione e la rivitalizzazione urbana. The contribution sta…
Chlorophyll-Protein Complexes of Chlorella fusca
1980
Chlorophyll-protein complexes from thylakoids of the normal type and two mutants of Chlorella fusca were separated using sodium dodecyl sulfate acrylamide gel electrophoresis (PAGE). The properties of the chlorophyll-protein complexes of the three strains of Chlorella were compared. Standard curves were set up for the characterization of the chlorophyll-proteins. In every electrophoretic separation of chlorophyll-protein complexes, a certain amount of pigment is separated from the protein. We tried to keep that amount as low as possible by mild solubilization and by working in low temperature. Under these conditions, we obtained several new chlorophyll-proteins in addition to the P-700-chl…
Light-harvesting chlorophyll protein (LHCII) drives electron transfer in semiconductor nanocrystals
2017
Type-II quantum dots (QDs) are capable of light-driven charge separation between their core and the shell structures; however, their light absorption is limited in the longer-wavelength range. Biological light-harvesting complex II (LHCII) efficiently absorbs in the blue and red spectral domains. Therefore, hybrid complexes of these two structures may be promising candidates for photovoltaic applications. Previous measurements had shown that LHCII bound to QD can transfer its excitation energy to the latter, as indicated by the fluorescence emissions of LHCII and QD being quenched and sensitized, respectively. In the presence of methyl viologen (MV), both fluorescence emissions are quenched…
Characterization of the Fast and Slow Reversible Components of Non-Photochemical Quenching in Isolated Pea Thylakoids by Picosecond Time-Resolved Chl…
1999
The fast and slow reversible components of non-photochemical chlorophyll fluorescence quenching commonly assigned to the qE and the qI mechanism have been studied in isolated pea thylakoids which were prepared from leaves after a moderate photoinhibitory treatment. Chlorophyll fluorescence decays were measured at picosecond resolution and analyzed on the basis of the heterogeneous exciton/radical pair equilibrium model. Our results show that the fast reversible non-photochemical quenching is completely assigned to the PS II antenna and is related to zeaxanthin. The slow reversible qI type quenching is located at the PS II reaction center and involves enhanced nonradiative decay of the prima…
Assessing and modeling nitrite inhibition in microalgae-bacteria consortia for wastewater treatment by means of photo-respirometric and chlorophyll f…
2022
Abstract Total nitrite (TNO2 = HNO2 + NO−2) accumulation due to the activity of ammonia-oxidizing bacteria (AOB) was monitored in microalgae-bacteria consortia, and the inhibitory effect of nitrite/free nitrous acid (NO2-N/FNA) on microalgae photosynthesis and inhibition mechanism was studied. A culture of Scenedesmus was used to run two sets of batch reactors at different pH and TNO2 concentrations to evaluate the toxic potential of NO2-N and FNA. Photo-respirometric tests showed that NO2-N accumulation has a negative impact on net oxygen production rate (OPRNET). Chlorophyll a fluorescence analysis was used to examine the biochemical effects of NO2-N stress and the mechanism of NO2-N inhi…
European National Road Authorities and Circular Economy: An Insight into Their Approaches
2020
The pavement engineering industry, having realized the significance of the impacts that it imposes on the environment through the production, construction and management of its products and assets, has been driven towards a more sustainable and circular way of operating. This has partly been through asphalt recycling, which is an area that many road authorities have prioritized. However, not all the National Road Authorities (NRAs) and/or sector stakeholders seem to be adequately familiar with the Circular Economy (CE) concept. This paper attempts to assist the transition of NRAs to a more circular way of doing business, by analyzing the current situation of CE within national/regional auth…
URBAN RESILIENCE AND WASTE MANAGEMENT: PROPOSALS OF NEW INFRASTRUCTURES FOR URBAN AREAS AND BUILDINGS
2015
La produzione ingente di rifiuti, quale conseguenza di costumi di vita volti allo spreco, rende vulnerabili i sistemi urbani che possono essere sottoposti, in casi emergenziali, a pressioni eccezionali e incontrollate con situazioni prossime al collasso. Un’opportuna e corretta gestione integrata dei rifiuti contribuisce alla resilienza dei sistemi urbani. Perciò si rendono necessarie la pianificazione e la progettazione di nuovi servizi e l’individuazione/integrazione di spazi e dotazioni tecnologiche per incentivare la popolazione a effettuare la raccolta differenziata in modo corretto e costante. Si presentano gli esiti di uno studio svolto in un piccolo centro siciliano. Partendo dalle …