The success of flotation operation depends upon the thriving interactions of chemical and physical variables. In this work, the effects of particle size, bubble size, and collector dosage on the bubble loading in a continuous flotation column were investigated. In other words, this work was mainly concerned with the evaluation of the true flotation response to the changes in the operating varia...

In a forthcoming book [Boehm-Turner, 2003], we have analyzed many organizations’ experiences with agile and disciplined methods, and have elaborated our previous characterization [Boehm, 2002] of the “home grounds” in which agile and disciplined methods have been most successful. This analysis has enabled us to determine five critical decision factors that organizations and projects can use to ...

Galway, Ireland Investigation of the Osteogenic Potential of Mesenchymal Stromal Cells derived from Human Umbilical Cord Tissue Pierre Moretti, Stefanie Boehm, Antonina Lavrentieva, Tim Hatlapatka, Ralf Hass, Thomas Scheper, Cornelia Kasper Corresponding Author: Kasper @iftc.uni-hannover.de 1 Institute of Technical Chemistry, University of Hannover, Hannover, Germany 2 Laboratory of Biochemistr...

This paper proposes a new short-circuit protection method for an IGBT. The proposed method is characterized by detecting not only gate charge but also gate voltage of the IGBT. This results in a shorter protection time, compared to the previous method that detects only the gate charge. A real-time monitoring system using an FPGA, A/D converters, and a D/A converter is used for the proposed prot...

Many of the current software systems rely on garbage collectors for automatic memory management. This is also the case for various software systems in realtime applications. However, a real-time application often requires an incremental working style of the underlying garbage collection, which renders the garbage collector more complex and less trustworthy. We present a formal verification of t...

To develop the organic Rankine-vapor compression ice maker driven by solar energy, a thermodynamic model was developed and the effects of generation temperature, condensation temperature, and working fluid types on the system performance were analyzed. The results show that the cooling power per square meter collector and ice production per square meter collector per day depend largely on gener...

The overall heat loss coefficient (U-value) of a vacuum tube solar collector is investigated experimentally and theoretically with regard to the pressure of the remaining gas inside the evacuated glass envelope. A number of collector tubes of same geometry are randomly selected from an installation of a solar based air-conditioning system and tested individually in the laboratory for the determ...

The maximum power cast on a collector from a source of finite angular extension by a concentrator of fixed position occurs when the collector sees the concentrator as a Lambertian source. Concentrators not fully meeting this requirement are evaluated using a parameter called the shape quality factor. Lambertian concentrators can be obtained with mirrors but not with lenses of finite n. In many ...

The Florida Solar Energy Center (FSEC), with the support of the National Renewable Energy Laboratory (NREL), has investigated the thermal performance of solar absorbers which are an integral yet indistinguishable part of a building’s roof. The first roof-integrated solar absorber (RISA) system was retrofitted into FSEC’S Flexible Roof Facility in Cocoa, Florida in September 1998. This “proof-of...

Current driven instabilities in the collector of III–V heterojunction bipolar transistors ~HBT! are investigated. Numerical simulations indicate that in a modified AlGaAs/GaAs HBT the collector current shows oscillatory behavior due to the transferred-electron ~Gunn–Hilsum! effect. Influence of the Kirk effect as well as conditions for oscillation are discussed. © 1995 American Institute of Phy...