Jewish refugees from Warsaw waiting at the border train station for transport to Germany Portraits; Groups

Weltkrieg 1914/18 Aus Warschau gefluechtete Juden, die auf einem Grenzbahnhof auf Abtransport nach Deutschland warten

Herbert Strauss at a Zurich train station returning from the International Meeting of the World Union for Progressive Judaism in London.

Strauss completed his PhD examinations summa cum laude before leaving for the meeting, and was on his way to the American Consulate to get a visa for the United States

Train with Jews Deported from Prague Artworks

Digital Image

Terezin, The Deportation Train.

Signed and dated lower right.

Flow-graph techniques for epicyclic gear train analysis

Flow-graph techniques are applied in this article for the analysis of an epicyclic gear train. A gear system based on this is designed and constructed for use in Numerical Control Systems.

step-up epicyclic gear-train and flowgraph analysis

An epicyclic gear-train system with a speed step-up of 1:10, useful for numerical control work, is presented. Also, the analysis of such a system is carried out using flowgraph techniques.

The Relationship between Decision Trees and the Scale of Train Data Set

Decision Trees need train samples in the train data set to get classification rules. If the number of train data was too small, the important information might be missed and thus the model could not explain the classification rules of data. While it is not affirmative that large scale of train data set can get well model. This Paper analysis the relationship between decision trees and the train data scale. We use nine decision tree algorithms to experiment the accuracy, complexity and robustness of decision tree algorithms. Some results are demonstrated.

Spectral effects for an ultrashort pulse train propagating in a two-level atom medium

We investigate the spectra of a femtosecond pulse train propagating in a resonant two-level atom (TLA) medium. it is found that higher spectral components can be produced even for a 2 pi femtosecond pulse train. Furthermore, the spectral effects depend crucially on both the relative shift phi and the delay time tau between the successive pulses of the femtosecond pulse train.

Coherent population accumulations of multiphoton transitions induced by an ultrashort pulse train in polar molecules

Coherent population accumulations of multiphoton transitions induced by an ultrashort pulse train in a two-level polar molecule are investigated theoretically by solving the density-matrix equations without invoking any of the standard approximations. It is shown due to the effects of permanent dipole moments, that the population accumulation of multiphoton transitions can be obtained in the polar molecule. Moreover, the population accumulations depend crucially on the relative phase between two sequential pulses, and the period in which the maximum population accumulation occurs is 2 pi/N in N-photon transitions.

Suspension mechanics: I. Inertial and non-Newtonian migration of neutrally buoyant rigid spheres in two-dimensional unidirectional flows; II. The effect of viscoelasticity on the creeping motion of a train of neutrally buoyant Newtonian drops through a circular tube

The lateral migration of neutrally buoyant rigid spheres in two-dimensional unidirectional flows was studied theoretically. The cases of both inertia-induced migration in a Newtonian fluid and normal stress-induced migration in a second-order fluid were considered. Analytical results for the lateral velocities were obtained, and the equilibrium positions and trajectories of the spheres compared favorably with the experimental data available in the literature. The effective viscosity was obtained for a dilute suspension of spheres which were simultaneously undergoing inertia-induced migration and translational Brownian motion in a plane Poiseuille flow. The migration of spheres suspended in a second-order fluid inside a screw extruder was also considered.

The creeping motion of neutrally buoyant concentrically located Newtonian drops through a circular tube was studied experimentally for drops which have an undeformed radius comparable to that of the tube. Both a Newtonian and a viscoelastic suspending fluid were used in order to determine the influence of viscoelasticity. The extra pressure drop due to the presence of the suspended drops, the shape and velocity of the drops, and the streamlines of the flow were obtained for various viscosity ratios, total flow rates, and drop sizes. The results were compared with existing theoretical and experimental data.