Gleichungen für die dynamische Viskosität und die Wärmeleitfähigkeit von reinem fluidem Wasser

Zusammenfassung Methoden zum Aufstellen von Gleichungen für die dynamische Viskosität und die Wärmeleitfähigkeit reiner fluider Stoffe werden angegeben und ihre Brauchbarkeit wird bei H₂O nachgewiesen. Es ergibt sich nur jeweils eine Gleichung für die Berechnung der Transportgrößen, die allerdings die Variablen Temperatur und Dichte anstelle von Temperatur und Druck enthält, dafür aber das ganze Gas- und Flüssigkeitsgebiet erfaßt. Es werden neue Erkenntnisse über die prinzipielle Abhängigkeit der Transportgrößen von Temperatur und Dichte gewonnen.

---

Equations for the dynamic viscosity and the thermal conductivity of pure fluid water substance

Methods for formulating equations for the dynamic viscosity and the thermal conductivity of pure fluid substances are given; their applicability is proved for H₂O. It is found that only one equation is needed to calculate the transport properties, which has the variables temperature and density instead of temperature and pressure, but covers the whole gaseous and liquid region. New knowledge of the principal dependence of the transport properties on temperature and density is attained.

---

---

Über dieses Thema wurde am 6. 10. 1969 auf dem Thermodynamik-Kolloquium des VDI in Zürich berichtet.     

Inelastic electron scattering from hydrogen at 50° and 60°

Inelastic electron scattering cross sections have been measured for four-momentum transfers between 4.1 GeV² and 30.5 GeV². At the large scattering angles of this experiment, the dominant contribution to the cross section comes from the W₁ structure function. In the conventional scaling variables, x and x′, this structure function does not exhibit scaling behavior, and at fixed x or x′ it is found to decrease with increasing four-momentum transfer.     

Two combinatorial covering theorems

A theorem in convex bodies (in fact, measure theory) and a theorem about translates of sets of integers are generalized to coverings by subsets of a finite set. These theorems are then related to quasigroups and (0, 1)-matrices.     

Light scattering from assemblies of spherulites

A general equation describing the small-angle H_v light-scattering intensity for a system of N undeformed spherulites located at random within the sample and taking into account the truncation and interference effects is given. Scattering contour plots or radial scans are reported for various arrangements of the N spherulites. The results show that the interference effect may explain the speckled appearance of the experimental patterns. Moreover, the interference and truncation effects (for the special cases where truncation is considered here) do not seem to shift the position of the maximum scattering angle of the cloverleaf pattern as calculated from the single spherulite theory. Finally, the calculations show that the truncation effect increases the relative intensity of the pattern at large and low scattering angles and at azimuthal angles 0 and 90°C, as compared with the intensity at the position of maximum scattering angle.     

Study of Anderson localization by a continued-fraction method

The electron localization is studied for Anderson's tight-binding model of a disordered two-dimensional square lattice. For a large system of 10⁴ sites the averaged squared modulus $\text{| G}{}_{00}\text{|}{}^2$ of the Green's function is evaluated by a continued-fraction method. From this quantity, following Anderson's criterion, the energy of the mobility edge is found as a function of the degree of disorder. Also the Anderson transition is recognized.     

Measurement of the analyzing power in p-->d-->(p p)n with a fast forward 1S0 proton pair

A measurement of the analyzing power A(y) of the p-->d--> (p p) + n reaction was carried out at the ANKE spectrometer at COSY at beam energies of 0.5 and 0.8 GeV by detection of a fast forward proton pair of small excitation energy E(pp) < 3 MeV. The S-wave dominance in the fast diproton is experimentally demonstrated in this reaction. While at T(p) = 0.8 GeV the measured analyzing power almost vanishes, it rises to nearly unity at T(p) = 0.5 GeV for neutrons emitted at theta(c.m.)(n) = 167 degrees. The results are compared with a model taking into account one-nucleon exchange, single scattering, and Delta(1232) excitation in the intermediate state. The model describes fairly well the unpolarized cross section obtained earlier and the analyzing power at 0.8 GeV; it fails to reproduce A(y) at 0.5 GeV.     

Aging in 1D discrete spin models and equivalent systems

We derive exact expressions for a number of aging functions that are scaling limits of nonequilibrium correlations, R(t(w),t(w)+t) as t(w)-->infinity, t/t(w)-->theta, in the 1D homogenous q-state Potts model for all q with T = 0 dynamics following a quench from T = infinity. One such quantity is (0)(t(w));sigma-->(n)(t(w)+t)> when n/square root of ([t(w))-->z. Exact, closed-form expressions are also obtained when an interlude of T = infinity dynamics occurs. Our derivations express the scaling limit via coalescing Brownian paths and a "Brownian space-time spanning tree," which also yields other aging functions, such as the persistence probability of no spin flip at 0 between t(w) and t(w)+t.     

Symmetry breaking of fluctuation dynamics by noise color

Activated escape is investigated for systems that are driven by noise whose power spectrum peaks at a finite frequency. Analytic theory and analog and digital experiments show that the system dynamics during escape exhibit a symmetry-breaking transition as the width of the fluctuational spectral peak is varied. For double-well potentials, even a small asymmetry may result in a parametrically large difference of the activation energies for escape from different wells.     

Book Review: The Emerging Consensus in Social Systems Theory. By Kenneth C. Bausch. Kluwer Academic/Plenum Publishers, 2001. ISBN 0-306-46539-6, $69.50

Nonlinear Dynamics, Psychology, and Life Sciences -