672 research outputs found
Sistemi innovativi nell\u2019attuazione della rintracciabilit\ue0 di filiera
Esposizione di sistemi per la tracciabilit\ue0 e la rintracciabilit\ue0 di filiera
The effects of cors network geometry and differential nrtk corrections on gnss solutions
The widespread availability of Continuosly Operating Reference Station (CORS) all over the world, allows to improve more scientific and technical studies on the use of satellite positioning techniques. The aim of this paper is to understand the effects of a GNSS CORS network geometry and differential corrections on the solutions. The analysis is carried out using ten different network configurations, with different inter-distances between the stations within GNSMART Geo++ software. The coordinates of one control point placed on the top of the Department of Engineering (University of Palermo, Italy) have been used to perform several static positioning mode test within fourthy hours. Different surveys have been performed, including four separate session tests, with acquisitions of one hour each. The analysis has been carried out using the traditional network solutions, such as the Virtual Reference Station (VRS), the Flächen Korrektur Parameter (FKP) and other two more recent techniques, which use the satellite corrections from the nearest (Near) and the farest (Far) stations. Results confirmed the great reliability of the GNSS network, with centimetre precision in terms of coordinates (North, East and Ellipsoidal Height), whether changing the geometric configuration of the network or the corrections
Influence of the Catalyst Particle Size on the Aqueous Phase Reforming of n-Butanol Over Rh/ZrO2
Butanol is a by-product obtained from biomass that can be valorized through aqueous phase reforming. Rh/ZrO2 catalysts were prepared and characterized, varying the size of the support particles. The results showed a relatively mild effect of internal mass transport on butanol conversion. However, the influence of internal transport limitations on the product distribution was much stronger, promoting consecutive reactions, i.e., dehydrogenation, hydrogenolysis, and reforming of propane and ethane. Hydrogen consuming reactions, i.e., hydrogenolysis, were more strongly enhanced than hydrogen producing reactions due to internal concentration gradients. Large support particles deactivated faster, attributed to high concentrations of butyraldehyde inside the catalyst particles, enhancing deposit formation via aldol condensation reactions. Consequently, also the local butyric acid concentration was high, decreasing the local pH, enhancing Rh leaching. The influence of internal transfer limitation on product distribution and stability is discussed based on a reaction scheme with three main stages, i.e., (1) formation of liquid intermediates via dehydrogenation, (2) formation of gas via decarbonylation/decarboxylation reactions, and (3) hydrocarbon hydrogenolysis/reforming/dehydrogenation
Intraluminal recanalization of long infrainguinal chronic total occlusions using the Crosser system
Purpose: To assess the safety and efficacy of a device for vibrational angioplasty in the
percutaneous intraluminal recanalization of long infrainguinal chronic total occlusions (CTO).
Technique: The Crosser CTO Recanalization System is a mechanical recanalization device
that uses high-frequency vibrational energy to disrupt and channel through fibrocalcific
plaque without harming the vessel wall, thus assisting in the recanalization of an occluded
artery. In 12 diabetic patients (7 men; median age 71 years, range 58–80) with critical limb
ischemia owing to long (median length 26 cm, range 21–32) infrainguinal CTOs resistant to
conventional guidewire techniques, the Crosser CTO Recanalization System was
successful in intraluminally crossing the occlusion in 9 (75%) patients in ,5 minutes
(mean 4:03 minutes). The safety endpoint (distal lumen guidewire position with no vessel
perforation or dissection) was achieved in all successful cases.
Conclusion: In our preliminary experience, the Crosser CTO Recanalization Catheter
decreased crossing time, was safe, and achieved a high rate of intraluminal recanalization
of long infrainguinal CTOs.
J Endovasc Ther. 2009;16:23–27
Key words: critical limb ischemia, chronic total occlusion, percutaneous interventions,
infrainguinal occlusion, intraluminal recanalization, vibrational energ
Aspetti dell'alimentazione di alcune specie di selaci del Canale di Sicilia
I Selaci occupano gli ultimi livelli delle reti trofiche marine: si tratta infatti di carnivori
che, spesso, predano risorse utili anche all'uomo. Numerose specie demersali (squali,
razze e torpedini) si alimentano, infatti, con organismi di interesse commerciale come
Aristeidi, Peneidi, Cefalopodi e Pesci ossei.
Le abitudini alimentari dei Selaci demersali del Canale di Sicilia sono quasi
completamente sc
onosciute; esistono in letteratura i lavori di Capapé relativi alle acque
tunisine, che si limitano ad una descrizione puramente qualitativa delle diete ma che
hanno tuttavia evidenziato preferenze verso Crostacei Decapodi, Cefalopodi e Teleostei.
Lo studio dei contenuti stomacali dei Selaci può fornire dunque elementi utili alla
comprensione delle reti trofiche demersali, all'indagine sull'esistenza di competizione tra
le diverse specie e allo studio dell'interferenza con prede di valore commerciale
A Review of Selected Applications of GNSS CORS and Related Experiences at the University of Palermo (Italy)
Services from the Continuously Operating Reference Stations (CORS) of the Global Navigation
Satellite System (GNSS) provide data and insights to a range of research areas such as physical
sciences, engineering, earth and planetary sciences, computer science, and environmental science.
Even though these fields are varied, they are all linked through the GNSS operational application.
GNSS CORS have historically been deployed for three-dimensional positioning but also for the
establishment of local and global reference systems and the measurement of ionospheric and tropospheric
errors. In addition to these studies, CORS is uncovering new, emerging scientific applications.
These include real-time monitoring of land subsidence via network real-time kinematics (NRTK) or
precise point positioning (PPP), structural health monitoring (SHM), earthquake and volcanology
monitoring, GNSS reflectometry (GNSS-R) for mapping soil moisture content, precision farming with
affordable receivers, and zenith total delay to aid hydrology and meteorology. The flexibility of CORS
infrastructure and services has paved the way for new research areas. The aim of this study is to
present a curated selection of scientific papers on prevalent topics such as network monitoring, reference
frames, and structure monitoring (like dams), along with an evaluation of CORS performance.
Concurrently, it reports on the scientific endeavours undertaken by the Geomatics Research Group at
the University of Palermo in the realm of GNSS CORS over the past 15 years
PROGETTAZIONE E VERIFICA SPERIMENTALE DI UNA MICROTURBINA IDRAULICA PER L\u2019INDUSTRIA ALIMENTARE
In questo articolo sono descritte le attivit\ue0 di ricerca e sviluppo di una micro-turbina idraulica inserita
all\u2019interno di un macchinario che opera un nuovo processo di abbattimento della carica batterica
applicabile nell\u2019industria dell\u2019imbottigliamento delle bevande. Peculiarit\ue0 della turbina progettata \ue8 la
geometria della palettatura della girante, dritta ed a sviluppo puramente assiale, che ne rende
estremamente economica la realizzazione. Lo scambio di energia avviene grazie al moto vorticoso
impresso al fluido (swirl) mediante opportuno posizionamento dei condotti di adduzione. Lo studio
della turbina \ue8 stato condotto mediante classico approccio unidimensionale, mentre il
dimensionamento \ue8 stato effettuato con l\u2019ausilio di simulazioni CFD. Ultimata la progettazione, la
turbina \ue8 stata realizzata e si \ue8 avviata una campagna di prove sperimentali su un banco di flussaggio
appositamente allestito che ha consentito di verificare il soddisfacimento delle specifiche progettuali
A semi-automatic system for labelling seafood products and obtaining fishery management data: A case study of the bottom trawl fishery in the central Mediterranean Sea
This study is on the implementation of a semi-automatic labelling system (LS) of the Mediterranean Sea seafood harvest to address the increased need for seafood authentication and inherent difficulties of commonly used indirect techniques for estimating fisheries yield and fishing effort. Sensitive datarequired for anti-counterfeit policies, such as date and catch area, can be acquired and recorded on the label by user-friendly automated software that excludes any possible manipulation by the crew. Based on results obtained from the installation of the LS on bottom commercial trawlers, the system certified the origin of the seafood products and simultaneously provided, indirectly, geospatial fisheries yield and fishing effort data of the main exploited species
Life cycle assessment of the biofuel production from lignocellulosic biomass in a hydrothermal liquefaction - aqueous phase reforming integrated biorefinery
The use of biofuels in the transport sector is one of the strategies for its decarbonization. Here, the LCA meth-odology was used for the first time to assess the environmental impacts of a biorefinery where hydrothermal liquefaction (HTL) and aqueous phase reforming (APR) were integrated. This novel coupling was proposed to valorize the carbon loss in the HTL-derived aqueous phase, while simultaneously reducing the external H2 de-mand during biocrude upgrading. Corn stover (residue) and lignin-rich stream (waste) were evaluated as possible lignocellulosic feedstocks. The global warming potential (GWP) was 56.1 and 58.4 g CO2 eq/MJbiofuel, respec-tively. Most of the GWP was attributable to the electrolysis step in the lignin-rich stream case and to the thermal duty and platinum use in the corn stover case. Other impact categories were investigated, and an uncertainty analysis was also carried out. A sensitivity analysis on biogenic carbon, electricity/thermal energy source and alternative hydrogen supply was conducted to estimate their influence on the GWP. Finally, the two scenarios were compared with the environmental impact of fossil-and other biomass-derived fuels, also considering fuel utilization. HTL-APR allowed a 37% reduction compared to fossil diesel, further reduced to 80% with the lignin -rich stream when green energy was used
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