The 6.4 keV iron emission line is typically created by irradiation of the neutral (or low ionized) iron by a hard X-ray source. Whereas the 6.7 and 7.0 keV emission lines are mainly produced by photoionization and collisional excitation in hot plasma, the 6.4 keV fluorescence line is typically a signature of either reflection from an accretion disc or absorption. We have surveyed the emission u...

Several versions of a hard disc microscopic ratchet are introduced and studied with molecular dynamics. While, at equilibrium, no rectification of the fluctuations takes place, a systematic motion appears when a temperature difference is applied to different units of the motor. In the limit of dilute gases, an exact analytic calculation of its properties is found to be in excellent agreement wi...

We present a simple, operatingsystem independent method to reduce the number of seek operations and consequently reduce the energy consumption of a hybrid storage device consisting of a hard disk and a flash memory. Trace-driven simulations show that migrating a tiny amount of the address space (0.0001%) from disk to flash already results in a significant storage energy reduction (12%) at virtu...

Advances in computing power. Computer processing speeds have increased a thousand-fold since the first microprocessor was introduced. The size of dynamic memory, which is used for active storage of the program code that is being executed, has reached capacities that exceed what used to be the standard for physical storage of data on a disk. These advances in processing speed and capacity have b...

Manufacturing yield control for hard disk media is getting tougher. This is proportional to the tremendous increases of its bit/inch storage capacity. With the significantly difficult lithography process will be involved and drastically increase in number of product total output volume that will be required in near future, conventional maintenance type is no longer feasible. This paper proposes...

Mechanical vibration on mobile hard disk is inevitable in the practical usage, and violent vibration may cause disk slip with significant position error, which will degrade the servo control performance, prolong time to ready (TTR) of servo and lower reading and writing speed of the magnetic head. The servo tracking accuracy of hard disk drive actuator with respect to various mechanical disturb...

ABSTRACT The paper presents research on modelling of HSM machine tool feed drive with use of Finite Element Method. The problems affecting generally considered machining accuracy were analysed, i.e. the problem of thermal displacements and the problem of displacements related to the feed drive stiffness. The research focused on possibility of simplifying (decreasing complexity) of the FEM model...

ABSTRACT We consider the parallel solution of sparse linear systems of equations in a limited memory environment. A preliminary out-of core version of a sparse multifrontal code called MUMPS (MUltifrontal Massively Parallel Solver) has been developed as part of a collaboration with members of the INRIA project GRAAL. In this context, we assume that the factors have been written on the hard disk...

We present new molecular dynamics results for the pressure of the pure hard disk fluid up to the hexatic transition (about reduced density 0.9). The data combined with the known virial coefficients (up to B10) are used to build an equation of state, to estimate higher-order virial coefficients, and also to obtain a better value of B10. Finite size effects are discussed in detail. The “van der W...

This paper proposes a new TDOF control scheme to minimize the tracking error caused by the neglected vibration modes of the plant. The design parameter is optimized from experimental data. The effectiveness is shown by simulation using a precise model of hard disk drive. Copyright c ©2005 IFAC.