Search results for "Heat Transfer"

Estimating rainfall erosivity by aggregated drop size distributions

2016

Rainfall erosivity is defined as the potential of the rain to cause erosion, and it can be represented by rainfall kinetic power. At first in this paper, the raindrop size distributions (DSD) measured by an optical disdrometer located at Palermo in the period June 2006–March 2014 and aggregated for intensity classes, are presented. Then an analysis of raindrop size characteristics is carried out, and the reliability of Ulbrich's distribution, using both the maximum likelihood and momentum estimate parameter methods, is tested. The raindrop size measurements are used to determine the experimental rainfall kinetic power values, which are compared with the ones calculated by a theoretically de…

Kernel intensity for space-time point processes with application to seismological problems

2010

Dealing with data coming from a space-time inhomogeneous process, there is often the need of semi-parametric estimates of the conditional intensity function; isotropic or anisotropic multivariate kernel estimates can be used, with windows sizes h. The properties of the intensities estimated with this choice of h are not always good for specific fields of application; we could try to choose h in order to have good predictive properties of the estimated intensity function. Since a direct ML approach cannot be followed, we propose an estimation procedure, computationally intensive, based on the subsequent increments of likelihood obtained adding an observation at time. The first results obtain…

Heat transfer by using TiO2 nanofluids

2021

Abstract In the last decades, nanofluids have been proposed as thermo-vector fluids thanks to their interesting properties of thermal conduction and stability, which allow interesting performance in heat transfer applications. Consequently, different studies on the thermal properties, the potential benefits, and the possible applications of nanofluids appeared in the scientific literature. This chapter deals with heat transfer characteristics of TiO2 nanofluids, which nowadays appear to be almost ready for practical applications. Particular attention has been given to the preparation, the characterization, and the effects of different parameters on heat transfer. Moreover, challenges and op…

A Test Rig for the Investigation of Free Convection Heat Transfer in Enclosures at High Rayleigh Number

1998

Measurement of Local Hot-Wall Heat Transfer in High-Rayleigh Number Free Convection Flow

1999

Influence of Rayleigh Number and End Wall Boundary Conditions on Free Convection Heat Transfer in a Rectangular Enclosure

2000

Investigation of the DEMO WCLL Breeding Blanket Cooling Water Activation

2020

Abstract Within the framework of the activities foreseen by the EUROfusion action on the cooling water activation assessment for a DEMO reactor equipped with a Water Cooled Lithium Lead Breeding Blanket (WCLL BB), the University of Palermo is involved in the assessment of dose rates induced by the decay of nitrogen radioisotopes produced by water activation, nearby the main components (e.g. isolation valves) of both First Wall (FW) and Breeder Zone (BZ) cooling circuits. In particular, the aim of this work is to evaluate the spatial distribution of nitrogen isotopes (16N and 17N) in the WCLL BB cooling circuits. To this purpose, a coupled neutronic/fluid-dynamic problem is solved following …

Über eine methode zur bestimmung der intensität komplexer photopeaks

1966

Abstract Analysing photopeaks really occuring in γ-ray spectra their asymmetrical structure can easily be demonstrated. To describe the shape of photopeaks this study therefore recommends the use of empirical functions instead of the normal distribution function. It can be shown, that in a wide energy and intensity range photopeaks are exactly described by two empirical functions which are normalized with respect to the fractional peak height. Taking account of this fact, a new procedure is derived which allows the decomposition of overlapping photopeaks even in the case of small energy distance and unfavorable intensity ratio. The method applied to numerous examples under practical conditi…

HEAT FLUX IN SUPERFLUID TRANSITION AND IN TURBULENT HELIUM COUNTERFLOW

[P149] Beam profile characteristic points designation for off-axis, wedged and FFF beams

2018

Purpose The main aim of this work is the search of characteristic points of a beam profile and application of these points for the TPS commissioning purposes. The comparison between profiles during the commissioning of the treatment planning system is a very important procedure. It is impossible to designate a field size for the off-axis, wedged and FFF beams directly using the definition of the on-axis symmetric field size. This work demonstrates how to compute good indicators of the field size that can be used for commissioning and QA purposes. Methods The proposal is to use profile inflection points as the beam profile characteristic points. The comparison of distances between inflection…