New analytical results in the electromagnetic response of composite superconducting wire in parallel fields

Analytical results are presented concerning the electromagnetic response of a composite superconducting wire in fields parallel to the wire axis, using the Maxwell equations supplemented with constitutive equations. The problem is nonlinear due to the nonlinearity in the constitutive equation describing the superconducting filaments. It is shown that the nonlinear behavior of the wire can be studied by analytical means. The method used gives an exact description of the response of a wire with nonconducting matrix material surrounding filaments with zero filament radius. For a composite wire it provides a very good approximatio

An application of the N-strip method of integral relations for analyzing the flow around a circular cone

The solution of sets of non-linear partial differential equations using the method of integral relations is considered. Emphasis is laid on the derivation of a general N-strip approximation algorithm. In order to check the applicability of this algorithm a program has been written to obtain the solution of the flow field around a circular cone at incidence in supersonic flow. Using the method of Stone, the angle of attack has been taken into account up to the second order. Thus a comparison can be made with the results given by Kopal.\ud \ud The results show that the N-strip algorithm in the case studied is a very attractive method which leads straight-forward to results of high accuracy

The Application of Domain Decomposition to Time-Domain Computations of Nonlinear Water Waves with a Panel Method

In this paper an iterative domain decomposition method for the solution of Laplace's equation is described and its effectiveness in time-domain computations of nonlinear water waves with a panel method is investigated. An important aspect of these computations is the varying shape of the free surface. The convergence of the iterative method is fast and leads to a speedup of the computations in the aforementioned application. The domain decomposition method gives a considerable reduction of memory requirements. Furthermore, it lends itself naturally for parallel computing

On the application of a new version of lifting surface theory to nonslender and kinked wings

Results are presented which are obtained by a new elaborate method developed at NLR for the determination of the characteristics of thin wings in subsonic flow. Attention is paid to the rate of convergence of the numerical solutions, especially with respect to the number of collocation points. Two rectangular wings have been treated in order to examine the influence of the aspect ratio. The influence of the rounding of a kink is demonstrated by means of a series of constant chord wings with hyperbolic edges

On the existence and uniqueness of the boundary layer equations for a rotating conducting flow

In this paper we have considered the question of the existence of the solution of a pair of coupled ordinary differential equations depending on a parameter s. By using a corollary of the Schauder-Tychonoff fixed point theorem, and some hard analysis — needed to cover essentially the range of s near s=0 — we were able to show that all the conditions for the theorem could be fulfilled. Hence existence for all values of s>0 was established.\ud \ud We also considered the question of uniqueness. There we used a number of rough estimates. In this way the calculations are largely simplified, but it is then not possible to prove uniqueness for all values of s. We only proved it for s>2.33

Evaluation of the probing profile of scanning force microscopy tips

It is demonstrated that a high-temperature-treated (305) surface of a SrTiO3 crystal can be used to evaluate the probing profile of AFM tips routinely, to provide a means of selecting perfect tips and to evaluate possible image distortions. This is important in order to recognize typical AFM artifacts which are caused by tips with truncated or twinned peaks which occur rather often in the case of microfabricated AFM needles. By means of selected needles, it is shown that also defective tips can give apparently rather perfect atomic resolution from flat crystal surfaces. Scope and limitations of the resolution of structural defects are discussed as the criterion for real atomic resolution

Tunneling induced electron transfer between separated protons

We study electron transfer between two separated nuclei using local control theory. By conditioning the algorithm in a symmetric system formed by two protons, one can favored slow transfer processes, where tunneling is the main mechanism, achieving transfer efficiencies close to unity assuming fixed nuclei. The solution can be parametrized using sequences of pump and dump pi pulses, where the pump pulse is used to excite the electron to a highly excited state where the time for tunneling to the target nuclei is on the order of femtoseconds. The time delay must be chosen to allow for full population transfer via tunneling, and the dump pulse is chosen to remove energy from the state to avoid tunneling back to the original proton. Finally, we study the effect of the nuclear kinetic energy on the transfer efficiency. Even in the absence of relative motion between the protons, the spreading of the nuclear wave function is enough to reduce the yield of electronic transfer to less than one half.Comment: 7 pages, 8 figure

A Sonogram of the Dark Side of the Dao: The Possibility of Antinatalism in Daoism

In the present work I study Daoist philosophy in conjunction with the radical new philosophy of antinatalism, spearheaded by South African philosopher David Benatar. Although I am not claiming equivalence between the two, a meaningful communication emerges between the classical Chinese sources used here and the modern doctrine of antinatalism. I argue that both visions partake in a radical critique of consciousness according to which this faculty of the human mind is far from what it is often held to be. In fact, it is perceived as a destructive and disruptive element of, and in, existence. Moreover, both offer a praxis of return that seeks to undo this disruption. In the case of Daoism, consciousness pushes humans ever farther away from the Dao. It is imperative to return from this exile, and to return to the Dao. This can, radically, only be achieved by the return from ‘ordinary’ conscious existence. This is the prerogative of sagehood. It will be shown that the trajectory of sagehood shares important parameters with the antinatalist quest to significantly (and perhaps conclusively) challenge human hubris in the cosmos at large, and to reinstate cosmic humility

TEM investigation of YBa2Cu3O7 thin films on SrTiO3 bicrystals

YBa2Cu3O7 films in c-axis orientation on bicrystalline SrTiO3 substrates are investigated by TEM. The films and the substrates are examined in cross-section and in plane view. The grain boundary of the bicrystal substrate contains (110) faceted voids, but is otherwise straight on a nanometer scale. Contrary to this, the film grain boundary is not straight grain boundary can be up to 100 nm for a 100 nm thick film. The deviation from the intended position of the YBCO grain boundary can already occur at the film/substrate interface where it can be as much as ±50 nm