1,721,000 research outputs found
Fascicular ratio: a new parameter to evaluate peripheral nerve pathology on magnetic resonance imaging: a feasibility study on a 3T MRI system.
No full textMedDensity
No full text.analisi della singola immagine
⁃ lettura da file digitali in formato immagine (.jpg, .jpeg, .tiff, .png, .bmp) di immagini biomedicali ricavate con tecniche radiografiche di qualsiasi natura (ecografia, tomografia, risonanza magnetica, mammografia, tomosintesi)
⁃ identificazione automatica e con soglia modificabile manualmente secondo le esigenze della porzione di immagine da analizzare
⁃ calcolo automatico quantitativo della densità della regione analizzata, definita come rapporto tra la superficie considerata densa e la superficie totale presa in considerazione, mediante metodi di analisi dell'istogramma dell'immagine (metodo della minimizzazione dell'entropia di Shanno e metodo integrale di calcolo, modelli di assorbimento della radiazione incidente esponenziale e lineare)
⁃ calcolo manuale quantitativo della densità dell'immagine mediante procedura interattiva guidata dall'utente
2. analisi automatica di serie di immagini
⁃ lettura di una serie di file contenuti in una cartella
⁃ procedura automatica di valutazione quantitativa di ogni singola immagine secono la procedura di cui al punto 1 (parte automatica)
⁃ salvataggio dei dati in un file di testo contenente tutte le informazioni necessarie
3. analisi automatica di serie di immagini tomografiche
⁃ lettura delle slices tomografiche contenute in una cartella
⁃ procedura automatica di valutazione quantitativa della densità delle immagini mediante procedimento di calcolo che permette la valutazione tridimensionale della densità
⁃ salvataggio dei dati in un file di testo contenente tutte le informazioni necessari
Liquefied natural gas submerged combustion vaporization facilities: process integration with power conversion units
No full textLiquefied natural gas (LNG) vaporization facilities offer an excellent opportunity of primary energy saving by means of integration with power conversion units that is still weakly exploited in actual installations. This work focuses on the evaluation of primary energy saving achievable by the integration of an LNG vaporization facility with a gas turbine and with a cogenerative combined gas-steam power plant. The fuel energy saving ratio is used as the main performance parameter to evaluate the primary energy saving derived by system integration, with respect to conventional submerged combustion vaporization. Twelve possible configurations are analyzed with steady-state calculations. Results show that a primary energy saving greater than 15% with peak values up to 27%, corresponding to 2.98TJ/year, is achievable. The paper shows that the fuel energy saving ratio can be used as a synthetic and effective parameter to estimate the energy-saving potential of different plant configurations. © 2011 John Wiley & Sons, Ltd
A classification methodology applied to existing room temperature magnetic refrigerators up to the year 2014
No full textMagnetic refrigeration at room temperature is a promising technology with the potential of competing with traditional vapor compression technology. It promises high energy conversion efficiency values, and is environmental friendly. In fact it can operate with zero ODP (Ozone Depletion Potential) and low GWP (Global Warming Potential) fluids. Furthermore the process and the plant configuration are very simple and the device promise to be very compact, with low noise and vibrations. The literature shows many prototypes developed and built both with proof of principle purposes and with performance oriented purposes. Very different embodiments and arrangements can be conceived, operating with similar or identical conceptual behavior. An existing classification methodology is discussed and applied to a wide set of prototypes and test sections known in the literature up to the year 2014. In this short review, most used configurations and trends are described according to the proposed classification criteria. The method is able to highlight common and uncommon solutions, and to show conceptual differences and similarities between different embodiments, irrespective of the engineering solutions chosen by the designer
DYNAMIC SUMULATION OF A SOLAR ASSISTED HEAT PUMP SWIMMING POOL WATER HEATING PILOT PLANT
No full text
A Dimensionless Description of Active Magnetic Regenerators to Compare their Performance and to Simplify their Optimization
No full textThe behavior of active magnetic regenerators (AMR) can be described by means of a one-dimensional set of equations. A lot of geometrical, thermo-physical and magnetic parameters influence the behavior and performance of an AMR, together with external controls and operating parameters. Literature data on AMR performances, both experimental and numerical, are given in different conditions and configurations, so that a consistent comparison among different results is not straightforward, and sometimes even not possible. In this paper the most relevant parameters are outlined, by means of a derivation of the dimensionless 1-D AMR equations. The resulting reduced number of key parameters simplifies the performance optimization procedure. Moreover, if the proposed dimensionless set of parameters is reported each time in corresponding scientific work, a comparison of experimental or/and numerical results would become much more feasible and easy to be performed
Heat Transfer Characterization of Packed Bed Regenerators by Means of an Inverse Technique
No full textA dynamic 1-D model for a reciprocating active magnetic regenerator; influence of the main working parameters
No full textAbstract
Active Magnetic Regeneration (AMR) is a configuration that allows magnetic refrigeration to be suitable also for room temperature applications. This work is intended to detect, by means of a 1-D numerical model, the influence on the regenerator performances of the working condition ambient temperature (TCURIE ± 20 K) and of the operating parameters fluid mass flow rate (utilization factor 0.5-3.5) and cycle frequency (0.1-0.6 Hz). Simulations show that, tuning the fluid mass flow rate, a gadolinium AMR (395 g, f = 0.25 Hz, B = 1.7 T) can reach a maximum cooling capacity of 130W and a 40W cooling power over a temperature span of 30 K. A COP of 5 can also be achieved with a temperature span of 30 K and a cooling power of 35 W. Frequency has a weak influence on the AMR’s COP, while the ambient temperature is crucial. The system loses the 60% of cooling capacity if the ambient temperature is 20 K away from the material Curie temperature
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