Evaluating Local Approximations of the L2-Orthogonal Projection Between Non-Nested Finite Element Spaces

We present quantitative studies of transfer operators between finite element spaces associated with unrelated meshes. Several local approximations of the global $L^2$-orthogonal projection are reviewed and evaluated computationally. The numerical studies in 3D provide the first estimates of the quantitative differences between a range of transfer operators between non-nested finite element spaces. We consider the standard finite element interpolation, Clément's quasi-interpolation with different local polynomial degrees the global $L^2$-orthogonal projection, a local $L^2$-quasi-projection via a discrete inner product, and a pseudo-$L^2$-projection defined by a Petrov-Galerkin variational equation with a discontinuous test space. Understanding their qualitative and quantitative behaviors in this computational way is interesting per se; it could also be relevant in the context of discretization and solution techniques which make use of different non-nested meshes. It turns out that the pseudo-$L^2$-projection approximates the actual $L^2$-orthogonal projection best. The obtained results seem to be largely independent of the underlying computational domain; this is demonstrated by four examples (ball, cylinder, half torus and Stanford Bunny).     

Detection of buried objects using infrared imaging of impulse laser heated soils

In this work we examine the time-dependent aspects of thermal imaging of buried metallic and non-metallic objects, when impulse heating of the soil surface is performed. A 1500 W carbon dioxide laser is used to provide the thermal impulse. Time-dependent thermal images are obtained using an infrared focal plane array camera and a gated data acquisition/analysis system. Experimental studies are conducted as a function of object material, size, and burial depth, and incident laser fluence. Quantitative evaluation of the surface temperature differentials as a function of time are presented.     

A partial phase diagram for a mixture of polystyrene with a low molecular weight styrene-dimethylsiloxane block copolymer

Differential scanning calorimetry (DSC) was used to examine the miscibility of polystyrene (PS), mol. wt. 10⁵, with a phase-separated styrene-dimethylsiloxane (S-DMS) diblock copolymer, M_n = 3800, 86 wt% S. Mixtures whose S content varied from 4 to 96 wt% PS were examined at a 10 K min^?1 heating rate following a 200 K min^?1 cooling rate from temperatures varying from 403 to 573 K. At some compositions, two glass transition temperatures, T_gs, corresponding to PS transitions were observed; at others only a single T_g was observed. When it was assumed that the 200 K min^?1 cooling rate corresponded to quenching from the starting temperature, and when the heat capacity changes at the S glass transitions were used to calculate the percentage of S repeat units undergoing each glass transition, it was possible to calculate an approximate partial phase diagram for this mixture. At 96 wt% PS, there was evidence for a small amount of mixed S phase, possibly block copolymer micelles, in equilibrium with PS; from about 60 to 90 wt% PS, the S repeat units from the block copolymer appeared to be completely mixed with the PS. At lower wt% PS, unmixed block copolymer was in equilibrium with block copolymer whose S segments were mixed with the PS. The phase diagram appeared to vary only slightly with temperature.     

Optische Absorption und Polarisation aufgedampfter Nickelschichten

The optical constantsk ²?n ² and 2n k of Ni-layers evaporated by electron bombardment had been investigated by polarimetric measurements in the spectral range 290 to 850 mμ. Considering the symmetric dependence of photocurrent on amplitude ratio and phase shift of the elliptic polarized light, a measuring accuracy of 5′ could be obtained with low electronic accessory. The influence of temperature of condensation and tempering on the optical properties is discussed.     

Eisen(III)-Aluminium-Mischhydroxide und deren katalytisches Verhalten

Zusammenfassung Es wurden mechanische Gemenge sowie Gemeinschaftsfällungen von röntgenamorphen Eisen(III)-hydroxid und Aluminiumoxidhydrat untersucht, die sich röntgenographisch nicht, wohl aber in ihrem katalytischen Vorhalten voneinander unterscheiden.     

Das Gammaspektrum des34Se81

The decay of Se⁸¹ (18 min) produced by neutron bombardement of natural Se and 98% enriched Se⁸¹ has been studied with the aid of scintillation-spectrometers. Gamma-rays have been observed and could be identified as belonging to the decay of Se⁸¹, revealing three excited levels in Br³¹ at (282±3) keV, (565±6) keV and (820±10) keV. The branching ratios of the beta-components are 98,7% leading to the ground state and (0,06±0,03)%, (0,85±0,20)% and (0,40±0,10)% leading to the excited states, respectively. The 565 keV-level decays to the ground state directly or by a cascade-transition with nearly equal intensities, the 820 keV-level mainly by a direct transition.     

Über Hydrosole von topochemischen röntgenamorphen Eisen-III-Hydroxiden

Ohne Zusammenfassung