Multifrequency composites seems to be a good approach to increase the acoustic bandwidth of standard piezoelectric composites. The mechanical coupling between the different piezoceramic elements introduces new degrees of freedom into their design. Monodimensional models have been developed to study their performances in a first approximation. In order to obtain a powerful design model, a two-di...

Introduction In two studies we conducted, untutored Grade 7 students produced solutions to a design-and-make task in ways significantly different than ones prescribed by many textbooks and theories about learning to design. We found that novice designers (a) sequence the subprocesses of designing quite differently than the prescribed models, (b) do not generate several possible solutions and ch...

The lack of a detailed comprehensive methodology for Data Warehouse development may be credited to fundamental differences in its requirements when compared to traditional database systems and the various approaches for the Data Warehouse architecture found in the literature. This paper presents a set of guidelines to support the incremental development of a Data Warehouse environment, created ...

In this paper, a method for three-dimensional modeling of tea-shoots with images and calculation models is introduced. The process is as follows: the tea shoots are photographed with a camera, color space conversion is conducted, using an improved algorithm that is based on color and regional growth to divide the tea shoots in the images, and the edges of the tea shoots extracted with the help ...

Background: A comprehensive database, comprising geometry and properties of human teeth, is needed for dentistry education and dental research. The aim of this study was to create a three-dimensional model of human teeth to improve the dental E-learning and dental research.   Methods: In this study, a cross-section picture of the three-dimensional model of the teeth was used. CT-Scan im...

The material balance used previously in one-dimensional mathematical models of porous electrodes is invalid when there is a nonzero volume change associated with the reaction. It is shown here how the material balance should be modified either to account for a loss in volume, or to account for an inflow of electrolyte from the header into the active pores. A one-dimensional mathematical model i...

The data warehousing and OLAP technologies are now moving onto handling complex data that mostly originate from the Web. However, intagrating such data into a decision-support process requires their representation under a form processable by OLAP and/or data mining techniques. We present in this paper a complex data warehousing methodology that exploits XML as a pivot language. Our approach inc...

Water distribution networks are subject to potential intentional contaminations to cause harm to the consumer. Reliable transport models are needed to detect, trace and follow any contaminant transported inside the network. For now, the transport of contaminants in pipes has been mostly modeled assuming perfect mixing conditions at T-junction. However, some studies have shown that it is not alw...

This paper deals with a 3 dimensional modeling of a polycrystalline silicon solar cell in steady state under constant multispectral illumination. After the resolution of the continuity equation the expression of photocurrent density and photovoltage are presented and the impact of the recombination velocity at grain boundaries and grain size on these parameters will also be considered. Keywords...