717 research outputs found
Experimental measurements of structural displacement during hydrogen vented deflagrations for FE model validation
No full textVented deflagration tests were conducted by UNIPI at B. Guerrini Laboratory during the
experimental campaign for HySEA project. Experiments included homogeneous hydrogen-air
mixture in a 10-18% vol. range of concentrations contained in an about 1 m 3 enclosure, called
SSE (Small Scale Enclosure). Displacement measurements of a test plate were taken in order
to acquire useful data for the validation of FE model developed by IMPETUS Afea. In this
paper experimental facility, displacement measurement system and FE model are briefly
described, then comparison between experimental data and simulation results is discussed
The role of the flow field generated by venting process on the pressure time history of a vented deflagration
No full text
Homogeneous hydrogen deflagrations in small scale enclosure. Experimental results.
No full textUniversity of Pisa performed experimental tests in a 1m3 facility, which shape and dimensions resemble a gas
cabinet, for the HySEA project, founded by the Fuel Cells and Hydrogen 2 Joint Undertaking with the aim to
conduct pre-normative research on vented deflagrations in real-life enclosures and containers used for hydrogen
energy applications, in order to generate experimental data of high quality. The test facility, named Small Scale
Enclosure (SSE), had a vent area of 0,42m2 which location could be varied, namely on the top or in front of the
facility, while different types of vent were investigated. Three different ignition location were investigated as
well, and the range of Hydrogen concentration ranged between 10 and 18% vol. This paper is aimed to
summarize the main characteristics of the experimental campaign as well as to present its results
Four Postulates of Quantum Mechanics Are Three
No full textThe tensor product postulate of quantum mechanics states that the Hilbert space of a composite system is the tensor product of the components’ Hilbert spaces. All current formalizations of quantum mechanics that do not contain this postulate contain some equivalent postulate or assumption (sometimes hidden). Here we give a natural definition of a composite system as a set containing the component systems and show how one can logically derive the tensor product rule from the state postulate and from the measurement postulate. In other words, our Letter reduces by one the number of postulates necessary to quantum mechanics
A clinical assessment of Sulindac in the treatment of arthrosis [Studio clinico sul Sulindac nel trattamento dell'artrosi]
No full textCaratteristiche antropometriche e composizione corporea di atleti praticanti il bodybuilding e la kickboxing
No full textIn this paper athletes practising bodybuilding and kickboxing were compared, as in these two disciplines weight and body composition have a great importance. The research was carried out on a sample from Sardinia (Italy) constituted by 22 subjects practising bodybuilding and 24 practising kickboxing. The following anthropometric measurements were taken: height, weight, circumferences and skinfold thickness, from which different anthropometric indices were calculated: Body Mass Index (BMI), Waist Hip Ratio (WHR), Arm Muscle Area (AMA), Arm Fat Area (AFA). The percentage of fat mass (FAT%%) was evaluated through skinfold techniques, using Jackson and Pollock (3 skinfolds) and Durnin and Womersley (4 skinfolds) equations. The average value of total height of athletes under scrutiny (172.94±6.45 cm for kickboxers and 172.06±8.98 cm for bodybuilders) was slightly higher than the average value of Sardinians (173.3 cm). Mean BMI for both groups fell within the range of normal weighted, but with a value significantly higher for (24.14±1.71 vs 22.76±1.71, p < 0.05). The two groups of athletes showed a different distribution of muscle mass, located prevalently in the upper limbs for the bodybuilders, in fact they presented higher values of arm circumference and AMA and lower values of biceps and triceps skinfold thickness. Kickboxers presented a lower distribution of subcutaneous fat in the trunk. Moreover, low percentage of fat mass characterize both kickboxers (3 skinfolds=7.70±2.32%; 4 skinfolds=11.53±2.99%) and bodybuilders (3 skinfolds=8.35±3.35%; 4 skinfolds=13.14±3.15%), and it is probably due to the intensive physical activity practised: 7.80±0.79 hours a week for kickboxers and 6.50±1.77 hours a week for bodybuilders.In questo lavoro si sono voluti mettere a confronto sportivi praticanti bodybuilding e la kickboxing, attività per le quali il peso e la composizione corporea assumono una valenza significativa. La ricerca è stata condotta su un campione, di origine sarda, di 22 atleti di bodybuilding e 24 atleti di kickboxing. Sono state rilevate le seguenti misure antropometrici: peso, statura, circonferenze e pliche, con i quali sono stati calcolati: l¿indice di massa corporea (BMI, Body Mass Index), il rapporto vita/fianchi (WHR, Waist Hip Ratio), l¿area muscolare e adiposa del braccio (AMA, Arm Muscle Area e AFA, Arm Fat Area). Il grasso percentuale (FAT%) è stata stimato tramite plicometria, utilizzando le formule Jackson e Pollock (3 pliche) e Durnin e Womersley (4 pliche). Il valore medio della statura totale degli atleti esaminati (172,94±6,45 cm nei kickboxer e 172,06±8,98 cm nei bodybuilder) è di poco superiore alla media regionale sarda di 171,3 cm. Il BMI medio rientra, per entrambi i gruppi, nel range di normopeso, ma con un valore significativamente superiore nei bodybuilder (24,14±1,71 vs 22,76±1,71, p < 0,05). Tra i due gruppi di atleti si è evidenziata una differente distribuzione della muscolarità, localizzata per i praticanti bodybuilding maggiormente nell¿arto superiore, essi registrano infatti valori più alti della circonferenza del braccio e dell¿indice di muscolarità AMA e più bassi valori delle pliche bicipitale e tricipitale, i kickboxer presentano una minor distribuzione di grasso sottocutaneo a livello del tronco. Si è riscontrato inoltre una ridotta massa grassa sia nei kickboxer (3 pliche=7,70±2,32%; 4 pliche=11,53±2,99%) che nei bodybuilder (3 pliche=8,35±3,35%; 4 pliche= 13,14±3,15%), dovuta sicuramente alla rilevante attività fisica praticata: 7,80±0,79 ore a settimana per i kickboxer e 6,50±1,77 ore a settimana per i bodybuilder
Risk analysis of complex hydrogen infrastructures
No full textDeveloping a future sustainable refuelling station network is the next important step to establish
hydrogen as a fuel for vehicles and related services. Such stations will most likely be integrated in
existing refuelling stations and result in multi-fuel storages with a variety of fuels being delivered,
stored and distributed, as e.g. biomass based methane, ethanol, gasoline, diesel as well as the
traditional crude oil based products. Hydrogen is also in play as intermediate energy storage to secure the power supply based on large shares of fluctuating energy sources and as an intermediate to improve the quality of biomass based fuels. Therefore, hydrogen supply and distribution chains will likely not only serve to fulfil the demands of refuelling, but may also be important for the wider electrical power and fuel industries. Based on an integrated hydrogen supply and distribution network, the application of the method of “Functional modelling” is discussed in this paper to show the complexity of the coupling between power storage for electricity supply and supplying hydrogen for transportation. It will be shown how a “Functional model” can be applied for comprehensive data storage for various assessment methodologies, and how functional models could support coherent risk and sustainability (Risk Assessment, Life Cycle Assessment /Life Cycle Costing) assessments, in order to find optimal solutions for the development of the infrastructure on a regional or national level
ATEX Directives: the new Approach – Classification of hazardous areas for the presence of flammable gas
No full text- …
