Showing papers by "Avram Bar-Cohen published in 1990"
TL;DR: In this article, the authors examined the influence of the dynamic solid/liquid contact angle and contact angle hysteresis on the incipience superheat of highly-wetting liquids and found that variations in contact angle induced by changes in the direction and magnitude of the liquid/vapor interface velocity can substantially affect the formation of bubble embryos.
107 citations
TL;DR: In this paper, experiments on pool boiling heat transfer in saturated R-113 at 1 atm pressure were conducted to investigate anomalies associated with the initiation of boiling using horizontal, 0.13 mm diameter chromel wires and a 0.51 mm diameter, platinum thin-film heater.
86 citations
23 May 1990
TL;DR: In this article, an experimental study of pool boiling was conducted using cylindrical heater surfaces of platinum, silicon, silicon dioxide, and aluminum oxide, which were immersed in FC-72 and R-113, saturated at 1-a.m. pressure.
Abstract: An experimental study of pool boiling was conducted using cylindrical heater surfaces of platinum, silicon, silicon dioxide, and aluminum oxide. They were immersed in FC-72 and R-113, saturated at 1-a.t.m. pressure. The effects of fluid and surface material on boiling incipience and on the nucleate boiling curve was investigated. A probabilistic representation was used to present the incipience wall superheat values, which scattered widely for ostensibly identical runs. The difference in incipience wall superheat values between those with FC-72 and R-113 was significant, but the surface material effect on boiling incipience was small. The surface material effect was more pronounced in the nucleate boiling regime than on the incipience process. >
35 citations
23 May 1990
TL;DR: In this paper, the authors presented the methodology and results of a Monte Carlo optimization of component placement on a printed circuit board and the overall reliability of the component mix on the printed circuit boards is the criterion of optimality.
Abstract: The methodology and results of a Monte Carlo optimization of component placement on a printed circuit board are presented. The overall reliability of the component mix on the printed circuit board is the criterion of optimality. Arrhenius relations are used to quantify the effect of temperature on the component failure rate. The finite element code called ANSYS is used to determine the temperature distribution in two conductively cooled printed circuit boards. The various strategies of the Monte Carlo annealing and cluster optimization methods and the effect of the relevant parameters on board reliability are discussed. >
25 citations
01 Jan 1990
23 citations
01 Jan 1990
16 citations
01 Dec 1990
11 citations
7 citations