An 8-DOF dual-arm system for advanced teleoperation performance experiments

This paper describes the electro-mechanical and control features of an 8-DOF manipulator manufactured by AAI Corporation and installed at the Jet Propulsion Lab. (JPL) in a dual-arm setting. The 8-DOF arm incorporates a variety of features not found in other lab or industrial manipulators. Some of the unique features are: 8-DOF revolute configuration with no lateral offsets at joint axes; 1 to 5 payload to weight ratio with 20 kg (44 lb) payload at a 1.75 m (68.5 in.) reach; joint position measurement with dual relative encoders and potentiometer; infinite roll of joint 8 with electrical and fiber optic slip rings; internal fiber optic link of 'smart' end effectors; four-axis wrist; graphite epoxy links; high link and joint stiffness; use of an upgraded JPL Universal Motor Controller (UMC) capable of driving up to 16 joints. The 8-DOF arm is equipped with a 'smart' end effector which incorporates a 6-DOF forcemoment sensor at the end effector base and grasp force sensors at the base of the parallel jaws. The 8-DOF arm is interfaced to a 6 DOF force reflecting hand controller. The same system is duplicated for and installed at NASA-Langley

The Semantic Classification in the Temporal Theory of Psychoanalysis

Many aspects of classification have been researched but the laws underlying changing classifications need to be focussed on. Psychoanalysis is a science dealing with the changing classifications within the individual. Aided by its theory, evolving over the last hundred years, psychoanalysis undertakes to provide actual scientific guidance in a person's changing his or her classifications or priorities in life. Such changes regularly occur in a psychoanalysis where, in the analytic setting, an analyst and an analysand form a unique relationship, usually lasting several years, for the purpose of analyzing the analysand's life. The analysand discovers his or her unique epistemologic categories as they developed based on a unique personal history. These epistemologic categories reflect both biographic achievements as well as constraints and, usually for the first time, become accessible for both understanding and change. While understanding and change can and does, to some extent, occur outside psychoanalysis, the psychoanalytic setting provides a unique opportunity to exclusively and systematically focus on such understanding and change

Magnetization distribution in the transverse Ising chain with energy flux

The zero-temperature transverse Ising chain carrying an energy flux j_E is studied with the aim of determining the nonequilibrium distribution functions, P(M_z) and P(M_x), of its transverse and longitudinal magnetizations, respectively. An exact calculation reveals that P(M_z) is a Gaussian both at j_E=0 and j_E not equal 0, and the width of the distribution decreases with increasing energy flux. The distribution of the order-parameter fluctuations, P(M_x), is evaluated numerically for spin-chains of up to 20 spins. For the equilibrium case (j_E=0), we find the expected Gaussian fluctuations away from the critical point while the critical order-parameter fluctuations are shown to be non-gaussian with a scaling function Phi(x)=Phi(M_x/)=P(M_x) strongly dependent on the boundary conditions. When j_E not equal 0, the system displays long-range, oscillating correlations but P(M_x) is a Gaussian nevertheless, and the width of the Gaussian decreases with increasing j_E. In particular, we find that, at critical transverse field, the width has a j_E^(-3/8) asymptotic in the j_E -> 0 limit.Comment: 8 pages, 5 ps figure

Testing the Elliott-Yafet spin-relaxation mechanism in KC8; a model system of biased graphene

Temperature dependent electron spin resonance (ESR) measurements are reported on stage 1 potassium doped graphite, a model system of biased graphene. The ESR linewidth is nearly isotropic and although the g-factor has a sizeable anisotropy, its majority is shown to arise due to macroscopic magnetization. Albeit the homogeneous ESR linewidth shows an unusual, non-linear temperature dependence, it appears to be proportional to the resistivity which is a quadratic function of the temperature. These observations suggests the validity of the Elliott-Yafet relaxation mechanism in KC8 and allows to place KC8 on the empirical Beuneu-Monod plot among ordinary elemental metals.Comment: 6 pages, 4 figures, submitted to Phys. Rev.

El fin de un imperio o la desunión soviética

La desaparición de la URSS, al igual que su nacimiento, es un hecho de gran significado histórico y, en primer lugar, es el derrumbe de un imperio. En este sentido es necesario conocer su origen y formación, su fraccionamiento y declive, así como las perspectivas que pueden tener aquellos pueblos que heredaron su historia. Aquí se presenta un esbozo histórico desde la formación de Rusia y su imperio: Periodo de Kiev (siglos IX-XII), hasta el fin de la URSS y la creación de la Comunidad de Estados Independientes (1991-1992). La situación actual de los quince Estados soberanos

Dynamic Scaling of Width Distribution in Edwards--Wilkinson Type Models of Interface Dynamics

Edwards--Wilkinson type models are studied in 1+1 dimensions and the time-dependent distribution, P_L(w^2,t), of the square of the width of an interface, w^2, is calculated for systems of size L. We find that, using a flat interface as an initial condition, P_L(w^2,t) can be calculated exactly and it obeys scaling in the form _\infty P_L(w^2,t) = Phi(w^2 / _\infty, t/L^2) where _\infty is the stationary value of w^2. For more complicated initial states, scaling is observed only in the large- time limit and the scaling function depends on the initial amplitude of the longest wavelength mode. The short-time limit is also interesting since P_L(w^2,t) is found to closely approximate the log-normal distribution. These results are confirmed by Monte Carlo simulations on a `roof-top' model of surface evolution.Comment: 5 pages, latex, 3 ps figures in a separate files, submitted to Phys.Rev.

Long range correlations in the non-equilibrium quantum relaxation of a spin chain

We consider the non-stationary quantum relaxation of the Ising spin chain in a transverse field of strength h. Starting from a homogeneously magnetized initial state the system approaches a stationary state by a process possessing quasi long range correlations in time and space, independent of the value of $h$. In particular the system exhibits aging (or lack of time translational invariance on intermediate time scales) although no indications of coarsening are present.Comment: 4 pages RevTeX, 2 eps-figures include