Search results for "Heat Transfer"

Derivation of Rainfall Thresholds for Flash Flood Warning in a Sicilian Basin Using a Hydrological Model

2016

Abstract The damages caused by flash floods are among the most onerous in terms of loss of lives and damage to properties. Derivation of rainfall threshold is one of the approaches commonly used for the development of flash flood warning systems. Specifically, rainfall threshold is the rainfall amount that, for a given basin area and duration, is enough to cause flooding and, therefore, it indicates the maximal sustainable rainfall for a basin. The aim of this paper is deriving flash flood-rainfall thresholds for a Sicilian basin (Italy) throughout a deterministic approach. The conceptual hydrological model TOPDM was used to estimate the amount of rainfall that, for given duration, hydrolog…

Simplified Probabilistic-Topologic Model for Reproducing Hillslope Rill Network Surface Runoff

2015

AbstractThis work presents a simplified probabilistic-topologic model for reproducing rill network surface runoff on a square-plane hillslope. The model requires only two parameters: the first is related to the production capacity of overland flow of the hillslope, at the initial conditions of the process, and the second depends on the sinuosity of the rill network. From a hydrological point of view, the following parameters account for the effects that essentially delineate the hydrologic response of a natural hillslope: rainfall intensity, hillslope roughness, and slope. Obviously, the reliability of the model is pending experimental validation that has only just begun. However, a prelimi…

A numerical study of thermal conditions in the THM growth of HgTe

2002

A numerical simulation of the travelling heater method (THM) process in the growth of HgTe is carried out. The whole system (furnace, ampoule and charge) is taken into account in the frame of a quasi-steady-state model. The mass conservation condition for the solute in the liquid zone permits the determination of the rate of advance of the crystallisation isotherm as a function of the heater position. We claim to study the evolution of different magnitudes along the growth process, searching for the physical reasons which could be at the origin of defects in the form of thin layers observed in some growing experiences. To solve the governing equations of fluid flow, heat transfer and mass t…

Natural Convection Heat Transfer in a Partially- or Completely-Partitioned Vertical Rectangular Enclosure

1991

The Latomiae of Syracuse: A Geotechnical Mapping Through Rock Reflectivity

2014

The archeological site of the Latomia del Paradiso (Syracuse) is endangered by severe instability phenomena due to the shape of walls and underground excava-tion related with the poor mechanical characteristics of the weathered and wet rock. The failure of huge blocks from the ceiling of the underground areas and the detaching of rock "flakes" from the walls surface make the geotechnical zon-ing particularly complex. the zoning is based on the characteristics of the rock wall surface that, in first approximation, can be distinguished in regularized sur-faces because of mining , and in irregular surfaces characterized by fracture prop-agation. The elaboration of reflectivity values obtained …

Two-Leg Squat Jumps in Water: An Effective Alternative to Dry Land Jumps

2009

The current study was designed to quantify and compare the kinetic parameters of two-leg squat jumps carried out on dry land, in water and in water using area devices that increase drag force. Twelve junior female handball players who had been competing at national level for the previous two years volunteered to participate in the study. Intensity of the two-leg squat jump was examined using a force plate (9 253-B11, Kistler Instrument AG, Winterthur, Switzerland) in three different conditions: on dry land, in water and in water using devices. An ANOVA with repeated measurements (condition) was applied to establish differences between the three jumps. The results show that peak impact force…

Real-time Control of Metallurgic Processes

1996

The careful control of the liquid metal solidification and the solid shell growth is of central importance in all metallurgic processes. These have a considerable influence on the formation of cracks and other defects which can be formed in the cast material. To ensure defect free products, the liquid metal is to be cooled down according to a pattern which depends i.e. on metal grade, product dimension, cooling speed and machine design. On the other hand, the control of the liquid/solid interface is a key element in optimising the liquid solidification with respect to good productivity. So, the heat transfer plays a very important role in metallurgic casting processes, especially when casti…

Analysing the link between export intensity, innovation and firm size in a science-based industry

2007

Abstract The aim of this paper is to contribute to a better understanding of the relationship between export intensity, innovation and size in a particular technological setting: a science-based industry. Using a sample of 121 firms in the French biotechnology industry, we have found that firm size is not a determinant for innovation or for export intensity. However, the results show a positive and significant link between innovation and export intensity. Our findings open a new agenda for policy-makers when interpreting how they should promote innovation and exports in science-based firms.

Gas-liquid mass transfer rates in unbaffled tanks stirred by PBT: scale-up effects and pumping direction

2018

Abstract Unbaffled stirred tanks are increasingly recognized as a viable alternative to common baffled tanks for a range of applications such as biochemical, food or pharmaceutical processes where the presence of baffles is undesirable for some reason. In this work, the mass transfer performance of unbaffled stirred tanks with pitched blade turbine, operating either in up-pumping or down-pumping mode, was investigated. The influence of impeller size and liquid viscosity were also investigated. The mass transfer intensity was measured by means of the Simplified Dynamic Pressure. Method The measurements concerned both coalescent and non-coalescent (viscous) batches. Results confirm that incre…

Application of low intensity ultrasonics to cheese manufacturing processes.

2002

Ultrasound has been used to non-destructively assess the quality of many foods such as meat, fish, vegetables and dairy products. This paper addresses the applications of low intensity ultrasonics in the cheese manufacturing processes and highlights the areas where ultrasonics could be successfully implemented in the future. The decrease of ultrasonic attenuation during the renneting process can be used to determine the optimum cut time for cheese making. The ultrasonic velocity increases during maturation for those types of cheese that become harder during this manufacturing stage, thus being an indicator of the maturity degree. Moreover, ultrasonic measurements could be linked to sensory …