IRON file systems

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Porosity and cell size control in alumina foam preparation by thermo-foaming of powder dispersions in molten sucrose

The foaming characteristics of alumina powder dispersions in molten sucrose have been studied as a function of alumina powder to sucrose weight ratio (WA/S) and foaming temperature. The increase in foaming temperature significantly decreases the foaming and foam setting time and increases the foam volume due to an increase in the rate of OH condensation as well as a decrease in the viscosity of the dispersion. Nevertheless, the foam collapses beyond a critical foaming temperature, which depends on the WA/S. The sintering shrinkage depends mainly on the WA/S and marginally on the foaming temperature. The porosity (83.4–94.6 vol.%) and cell size (0.55–1.6 mm) increase with an increase in foaming temperature (120–170 °C) and a decrease in WA/S (0.8–1.6). The drastic decrease in compressive strength and modulus beyond a WA/S of 1.2 is due to the pores generated on the cell walls and struts as a result of particle agglomeration. Gibson and Ashby plots show large deviation with respect to the model constants ‘C’ and ‘n’, especially at higher alumina powder to sucrose weight ratios

High Throughput Data Transfers using the Tornado Transport Protocol

Abstract — The need to transfer extremely large files over very high bandwidth network paths is becoming more and more common. Current windowbased transport protocols often limit throughput to a level well below what might otherwise be achievable. In this paper we describe and evaluate the Tornado Transport Protocol (TTP) which is designed to be reliable, to achieve very high throughput and to maintain an adjustable level of TCP-friendliness. Reliability is achieved through the use of efficient forward error correction. High throughput is achieved by eliminating the need for acknowledgment-based pacing from the receiver. TCP-friendliness is achieved by setting a threshold to specify when to react to loss. We compare TTP with an out-of-the-box configuration of TCP NewReno and two TCP-based methods for high throughput file transfers under a variety of traffic conditions. Our simulations show that for large file transfers in long delay, large bandwidth environments, TTP achieves throughput nearly an order of magnitude higher than out-of-the-box TCP NewReno, and up to 300 % higher than the next best high performance transport protocol. In each case we assess TCP-friendliness and find that TTP effectively allows competing TCP flows a fair share of bandwidth. I