This paper describes the design and implementation of a garbage collection scheme on large-scale distributed-memory computers and reports various experimental results. The collector is based on the conservative GC library by Boehm & Weiser. Each processor traces local pointers using the GC library while traversing remote pointers by exchanging \mark messages" between processors. It exhibits a p...

In this paper, we report the development of a high breakdown voltage InGaP/GaAs HBT process for low-to-mid power and high-voltage power amplifier operation. To achieve the high-breakdown InGaP HBT, two different collector designs and collector-etch processes were investigated. The first device process approach uses a thick GaAs collector with low n doping. The process challenges and considerati...

Multistage collectors are commonly used in travelling wave tubes (TWTs), klystrons, gyrotrons and inductive output tubes (IOTs). A dc beam transfers some of its energy to the input RF wave during its travel through the interaction circuit. The purpose of a collector is to recover most of the remaining dc power from the spent beam and thereby increase both the collector and the overall efficienc...

In this paper, artificial neural networks (ANNs) and genetic algorithms (GAs) are used for the design of solar flat-plate collectors. It is proved in this paper that by using the Taguchi method for selecting the data required for training the ANN is very effective in allowing the network to learn the behavior of the system satisfactorily. The parameters on which the flat-plate collector design ...

Our research is concerned with compiler-independent, tag-free garbage collection for the C ++ programming language. This paper presents a mark-and-sweep collector , and explains how it ameliorates shortcomings of a previous copy collector. The new collector, like the old, uses C ++ 's facilities for creating abstract data types to deene a tracked reference type, called roots, at the level of th...

This paper reports the thermal performance of a new cylindrical solar collector based on an experimental investigation with this difference that instead of the collector tube with absorbent coating, coil into a spiral copper tube is placed in the center of the collector. The spiral shape of the tube, heat transfer without disruption or increase the heat transfer area, is increasing. In this cas...

This paper demonstrates the advantages of extending the scope of prototyping to the requirements capture phase of a project. Prototyping has long been used to elicit users’ responses to ready-formed designs (Boehm, 1988), but only recently has the use of concept demonstrators (Sanderson, 1997) and early throw-away prototypes (Smith et al., 1990) been suggested as a means to capture response to ...

In the present study, a new magnetic powder based on magnetite can be used as a petroleum crude oil collector. Amidoximes based on rosin as a natural product can be prepared from a reaction between hydroxylamine and rosin/acrylonitrile adducts. The produced rosin amidoximes were used as capping agents for magnetite nanoparticles to prepare hydrophobic coated magnetic powders. A new class of mon...

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...

This paper deals with photovoltaic-thermal (PV/T) collectors that combine photovoltaic (PV) module and solar thermal (ST) modules to provide heat electricity simultaneously. The use of a PV/T system not only enhances PV efficiency but also allows energy for various heating applications. performance evaluation the had been investigated both theoretically experimentally past few years. In this wo...