26,496 research outputs found
Remote Stratigraphic Analysis: Combined TM and AIS Results in the Wind River/bighorn Basin Area, Wyoming
An in-progress study demonstrates the utility of airborne imaging spectrometer (AIS) data for unraveling the stratigraphic evolution of a North American, western interior foreland basin. AIS data are used to determine the stratigraphic distribution of mineralogical facies that are diagnostic of specific depositional environments. After wavelength and amplitude calibration using natural ground targets with known spectral characteristics, AIS data identify calcite, dolomite, gypsum and montmorillonite-bearing strata in the Permian-Cretaceous sequence. Combined AIS and TM results illustrate the feasibility of spectral stratigraphy, remote analysis of stratigraphic sequences
High Frequency Scattering from Arbitrarily Oriented Dielectric Disks
Calculations have been made of electromagnetic wave scattering from dielectric disks of arbitrary shape and orientation in the high frequency (physical optics) regime. The solution is obtained by approximating the fields inside the disk with the fields induced inside an identically oriented slab (i.e. infinite parallel planes) with the same thickness and dielectric properties. The fields inside the disk excite conduction and polarization currents which are used to calculate the scattered fields by integrating the radiation from these sources over the volume of the disk. This computation has been executed for observers in the far field of the disk in the case of disks with arbitrary orientation and for arbitrary polarization of the incident radiation. The results have been expressed in the form of a dyadic scattering amplitude for the disk. The results apply to disks whose diameter is large compared to wavelength and whose thickness is small compared to diameter, but the thickness need not be small compared to wavelength. Examples of the dependence of the scattering amplitude on frequency, dielectric properties of the disk and disk orientation are presented for disks of circular cross section
Inclusion of new LHC data in MMHT PDFs
I consider the effects of including a variety of new LHC data sets into the
MMHT approach for PDF determination. I consider the impact of fitting new LHC
and Tevatron data, which leads to clear improvements in some PDF uncertainties.
There are specific issues with ATLAS 7 TeV jet data and I include a discussion
of the treatment of correlated uncertainties and briefly the effects of NNLO
corrections. I also present preliminary results with the inclusion of the high
precison final ATLAS 7 TeV rapidity-dependent data.Comment: 6 pages. To appear in proceedings of DIS2017 Worksho
The moduli space of hypersurfaces whose singular locus has high dimension
Let be an algebraically closed field and let and be integers with
and Consider the moduli space of
hypersurfaces in of fixed degree whose singular locus is
at least -dimensional. We prove that for large , has a unique
irreducible component of maximal dimension, consisting of the hypersurfaces
singular along a linear -dimensional subspace of . The proof
will involve a probabilistic counting argument over finite fields.Comment: Final version, including the incorporation of all comments by the
refere
Updates of PDFs in the MSTW framework
I present results on updates on PDFs which are obtained within the general
framework which led to the MSTW2008 PDF sets. There are some theory and
procedural improvements and a variety of new data sets, including many relevant
up-to-date LHC data. A new set of PDFs is very close to being finalised, with
no significant changes expected to the preliminary PDFs shown here.Comment: 6 pages, 6 figures,Published in PoS DIS (2014
Smart Materials as Intelligent Insulation
In order to provide a robust infrastructure for the transmission and distribution of electrical power, understanding and monitoring equipment ageing and failure is of paramount importance. Commonly, failure is associated with degradation of the dielectric material; therefore the introduction of a smart moiety into the material is a potentially attractive means of continual condition monitoring. It is important that any introduction of smart groups into the dielectric does not have any detrimental effect on the desirable electrical and mechanical properties of the bulk material. Initial work focussed on the introduction of fluorophores into a model dielectric system. Fluorescence is known to be a visible effect even at very low concentrations of active fluorophores and therefore was thought well suited to such an application. It was necessary both to optimise the active fluorophore itself and to determine the most appropriate manner in which to introduce the fluorophores into the insulating system. This presentation will describe the effect of introducing fluorophores into polymeric systems on the dielectric properties of the material and the findings thus far [1]. Alternative smart material systems will also be discussed along with the benefits and limitations of smart materials as electric field sensors
On the transcendence degree of the differential field generated by Siegel modular forms
It is a classical fact that the elliptic modular functions satisfies an
algebraic differential equation of order 3, and none of lower order. We show
how this generalizes to Siegel modular functions of arbitrary degree. The key
idea is that the partial differential equations they satisfy are governed by
Gauss--Manin connections, whose monodromy groups are well-known. Modular theta
functions provide a concrete interpretation of our result, and we study their
differential properties in detail in the case of degree 2.Comment: 21 pages, AmSTeX, uses picture.sty for 1 LaTeX picture; submitted for
publicatio
Extinction toward the Compact HII Regions G-0.02-0.07
The four HII regions in the Sgr A East complex: A, B, C, and D, represent
evidence of recent massive star formation in the central ten parsecs. Using
Paschen-alpha images taken with HST and 8.4 GHz VLA data, we construct an
extinction map of A-D, and briefly discuss their morphology and location.Comment: 2 pages, 1 figure. To be published in the Astronomical Society of the
Pacific Conference Series Proceedings of the Galactic Center Workshop 2009,
Shangha
- …