Electronic Currents and Anapolar Response Induced in Molecules by Monochromatic Light

It is shown that the electric dipole- and electric quadrupole–anapole polarizabilities, denoted respectively by fαβ′ and gα,βγ′, and the anapole magnetizability aαβ, are intrinsic properties of the electron cloud of molecules responding to optical fields. fαβ′ is a nonvanishing property of chiral and achiral compounds, whereas aαβ is suitable for enantiomer discrimination of chiral species. They can conveniently be evaluated by numerical integration, employing a formulation complementary to that provided by perturbation theory and relying on the preliminary computation of electronic current density tensors all over the molecular domain. The origin dependence of the dynamic anapolar response is rationalized via related computational techniques employing numerical integration, as well as definitions of molecular property tensors, for example, electric dipole and electric quadrupole polarizabilties and magnetizability. A preliminary application of the theory is reported for the Ra enantiomer of the hydrogen peroxide molecule, evaluating tensor components of electric dipole-anapole polarizability and anapole magnetizability as functions of the dihedral angle ϕ≡∠ H-O-O-H in the range 0∘≤ϕ≤180∘.

Impact of the Icelandic hotspot on GPS time series in southeast Greenland

<p>The mass lost from Greenland ice sheet is one of the most important contribution to the global sea level rise, and it is under constant monitoring. However, still little is known about the heat flux at the glacier bedrock, and how it affects dynamics of the major outlet glaciers in Greenland. Recent studies suggest that the hotspot currently under Iceland have been under eastern Greenland at ~40 Ma BP and that the upwelling of hot material from the Iceland plume towards Greenland is ongoing. A warm upper mantle has a low viscosity, which in turn causes the solid Earth to rebound much faster to deglaciation. We have good reasons to believe that mantle beneath SE-Greenland has very low viscosity (Khan, et al. 2016), as also suggested by the discrepancy between the GPS velocities and the predicted purely elastic deformations caused by present-day ice loss. Here we present a preliminary computation of the Earth deformation driven by a low viscosity mantle excited by the deglatiation since the little ice age (LIA) to the present day. We produce the time series of such deformation and compare it with GPS time series, the oldest dating back to 1992.</p>

High Precision Angular and Linear Measurements Using Universal Opto-Electronic Measuring Modules in Distributed Measuring Systems

Large or long objects require measuring systems as a combination of more than one measuring instrument. In this case, the combination of instruments consists of one central module and several measuring modules. The measuring modules make the preliminary computation of measuring information and translate it to the central module for final computation of measuring parameters. The central module also makes statistics of measuring and archive information. Some tasks require noncontact measurement of angular and linear coordinates of objects or places. The optoelectronic measuring devices (OEMD) are ideal for these purposes. These devices also have other advantages such as high precision and adaptability. One and two coordinates high precision modules based on matrix and linear CCD or CMOS photo sensors are described. In this article variants of the distributed measuring systems are described. The basic attention is given to the description of the unified optoelectronic modules for measurement of angular and linear coordinates. Basic parameters and application examples of measuring modules are presented.

Processing the CAD Model of Sculptured Artifacts for Free-Form Thick-Layered Object Manufacturing

Processing CAD models of large sized, structurally complex, and dominantly sculptured objects for free-form thick-layered object manufacturing (FF-TLOM) is a non-trivial task. Algorithmic support is needed, especially when the applicators of the FF-TLOM technology are not specialized experts. The research team of the authors has developed and programmed a system of such algorithms to prepare NURBS-based assembly models for layered manufacturing, but also to control both the cutting tool and the manufacturing equipment. This paper starts with a brief overview of the FF-TLOM technology and the concept of reducing a CAD model to fabrication elements. Then, it explains the high-level concepts supporting the algorithms, and presents the details of their operation. The logically linked system of algorithms is applied to find the best position for segmentation. The best segmentation orientation can be found in a computation-intensive, multi-criterion optimization process. It is difficult to simplify and speed up, for the valuation of the parameters of the objective function cannot be done without a preliminary computation of the segments and layers.

Feasibility of a 5 T Magnet by using Bi-2223/Ag Tape at 30 K

The feasibility of a 5 T magnet by using Bi-2223/Ag tapes at 30 K has been investigated. Preliminary computation demonstrates that the target is attainable by assembling 20 double pancakes manufactured by co-winding two Bi-2223/Ag tapes having overall cross-section of 0.25 × 3.5 mm 2 and 25% fill factor, being the expected operating current about 200 A. The pancakes located at the edges are the most critical because the component of the magnetic field orthogonal to the tape surface is large enough to strongly depress J c . To overcome this problem the edge pancakes could be fabricated by using Bi-2223/Ag tapes with new concept design (e.g. with oriented filaments).