BEAUTIFUL FORMS AND COMPOSITIONS ARE NOT MADE BY CHANCE: EXPLORING THE EFFICACY OF PORTABLE X-RAY FLUORESCENCE TO SORT AND SOURCE ENGLISH LEAD GLAZED CERAMICS

Advances in portable X-ray fluorescence (pXRF) technology have made it a viable option for the non-destructive exploration of the underlying chemical composition of ceramic artifacts for the purposes of classification. However, because the literature regarding the use of this instrument on historic artifacts is limited, it is necessary to begin with a broad scale exploratory assessment that might act as a jumping off point for future studies on this topic. Toward that end, this research uses a collection of British and Continental European ceramics ranging from 1650-1920, owned and curated by the Chipstone Foundation in Fox Point, WI, to explore the efficacy of using pXRF to sort and source those materials. The chemical patterns in the data are tested against the known provenance of these artifacts which has been pre-determined by ceramic experts and material culture analysts. Of the 102 samples that have been tested, primary focus is given to items crafted in London and Staffordshire which account for the largest portion of artifacts in the dataset. Principle component analysis is used to better understand the underlying structure of the entire dataset to ultimately reduce the number of chemical variables to those that best distinguish each group. Using those particular chemical variables, a separate dataset of London and Staffordshire mean intensity readings is subjected to factor analysis which resulted in two components being identified. The calculated factor scores are incorporated into a binary logistic regression model to determine if the samples can be correctly sorted into their pre-established provenance categories. A second model that incorporates the year of production is also presented which shows an improved ability to classify those samples. These results are ultimately situated within the historic context of the pottery making industry in England which was highly influenced by the Industrial Revolution and developments in ceramic technology

Axially deformed solution of the Skyrme-Hartree-Fock-Bogolyubov equations using the transformed harmonic oscillator basis (III) hfbtho (v3.00): a new version of the program

We describe the new version 3.00 of the code HFBTHO that solves the nuclear Hartree-Fock (HF) or Hartree-Fock-Bogolyubov (HFB) problem by using the cylindrical transformed deformed harmonic oscillator basis. In the new version, we have implemented the following features: (i) the full Gogny force in both particle-hole and particle-particle channels, (ii) the calculation of the nuclear collective inertia at the perturbative cranking approximation, (iii) the calculation of fission fragment charge, mass and deformations based on the determination of the neck (iv) the regularization of zero-range pairing forces (v) the calculation of localization functions (vi)MPI interface for large-scale mass table calculations.Comment: 29 pages, 3 figures, 4 tables; Submitted to Computer Physics Communication

Computing Heavy Elements

Reliable calculations of the structure of heavy elements are crucial to address fundamental science questions such as the origin of the elements in the universe. Applications relevant for energy production, medicine, or national security also rely on theoretical predictions of basic properties of atomic nuclei. Heavy elements are best described within the nuclear density functional theory (DFT) and its various extensions. While relatively mature, DFT has never been implemented in its full power, as it relies on a very large number (~ 10^9-10^12) of expensive calculations (~ day). The advent of leadership-class computers, as well as dedicated large-scale collaborative efforts such as the SciDAC 2 UNEDF project, have dramatically changed the field. This article gives an overview of the various computational challenges related to the nuclear DFT, as well as some of the recent achievements.Comment: Proceeding of the Invited Talk given at the SciDAC 2011 conference, Jul. 10-15, 2011, Denver, C

Nuclear energy density optimization: Shell structure

Nuclear density functional theory is the only microscopical theory that can be applied throughout the entire nuclear landscape. Its key ingredient is the energy density functional. In this work, we propose a new parameterization UNEDF2 of the Skyrme energy density functional. The functional optimization is carried out using the POUNDerS optimization algorithm within the framework of the Skyrme Hartree-Fock-Bogoliubov theory. Compared to the previous parameterization UNEDF1, restrictions on the tensor term of the energy density have been lifted, yielding a very general form of the energy density functional up to second order in derivatives of the one-body density matrix. In order to impose constraints on all the parameters of the functional, selected data on single-particle splittings in spherical doubly-magic nuclei have been included into the experimental dataset. The agreement with both bulk and spectroscopic nuclear properties achieved by the resulting UNEDF2 parameterization is comparable with UNEDF1. While there is a small improvement on single-particle spectra and binding energies of closed shell nuclei, the reproduction of fission barriers and fission isomer excitation energies has degraded. As compared to previous UNEDF parameterizations, the parameter confidence interval for UNEDF2 is narrower. In particular, our results overlap well with those obtained in previous systematic studies of the spin-orbit and tensor terms. UNEDF2 can be viewed as an all-around Skyrme EDF that performs reasonably well for both global nuclear properties and shell structure. However, after adding new data aiming to better constrain the nuclear functional, its quality has improved only marginally. These results suggest that the standard Skyrme energy density has reached its limits and significant changes to the form of the functional are needed.Comment: 18 pages, 13 figures, 12 tables; resubmitted for publication to Phys. Rev. C after second review by refere

One-nucleon transfer reactions and the optical potential

We provide a summary of new developments in the area of direct reaction theory with a particular focus on one-nucleon transfer reactions. We provide a status of the methods available for describing (d,p) reactions. We discuss the effects of nonlocality in the optical potential in transfer reactions. The results of a purely phenomenological potential and the optical potential obtained from the dispersive optical model are compared; both point toward the importance of including nonlocality in transfer reactions explicitly. Given the large ambiguities associated with optical potentials, we discuss some new developments toward the quantification of this uncertainty. We conclude with some general comments and a brief account of new advances that are in the pipeline.Comment: 7 pages, 5 figures, proceedings for the 14th International Conference on Nuclear Reaction Mechanisms, Varenna, June 201