New Approach to Determine Atomic Arrangement in Materials

RTNN researchers at NC State University have published an article describing a new way to determine how atoms are arranged in materials. The work, “Use of Bayesian Inference in Crystallographic Structure Refinement via Full Diffraction Profile Analysis” published in Scientific Reports describes the application of Bayesian statistical methods to X-ray diffraction patterns. This method allows researchers to characterize and better estimate the variability in a material’s atomic structure. The technique is under development for use with spectra collected from other analytical tools like X-ray photoelectron spectroscopy. This tool-set will inform the development of materials for a variety of novel applications.

A press release describing the work can be found here. The article in its entirety can be found here.

 

Materials Science in Caribbean Art and Archaeology: Two Case Studies

Prof MartinezThe Research Triangle Nanotechnology Network is excited to announce an upcoming seminar by Professor Antonio Martínez-Collazo. Professor Martínez joins us from the Physics Department at the University of Puerto Rico. He will present his work using materials characterization techniques to study works of art and archaeological artifacts. Following the talk, the Analytical Instrumentation Facility (AIF) at NC State will host tours for interested attendees to learn more about available characterization techniques and instrumentation.

Click here to register for a tour. Questions can be directed to rtnanonetwork@ncsu.edu.

Parking information: There are Centennial Campus pay-by-space parking spots available in the Poulton Deck and Partners Way Deck. More information about parking at NC State can be found here.

Seminar Abstract:

In recent years, materials science characterization techniques have been increasingly applied in the study of works of art and archaeological artifacts.  These studies have been geared to inform the efforts of art historians and conservators in order to obtain a better understanding of the degradation processes that occur in art pieces, to establish the palette and practices of particular artists, and to aid in forensic efforts to identify forgeries and fakes.  In archaeology, materials characterization techniques have been used in the interrogation of archaeological artifacts in order to derive information about the individuals who originally fabricated them and their communities.  This talk will report on two such applications.

madonnaFirst, we will consider a study involving image acquisition techniques and x-ray fluorescence spectroscopy to a painting by José Campeche y Rivafrecha, one of the first and most important Puerto Rican painters of the18th century.  The oil-over-wood- panel painting, known as “La Virgen de Belén” or Bethlehem’s Madonna, portrays a nursing Madonna and child scene.  Campeche executed a large number of paintings with very similar compositions, i.e showing the female figure nursing a child with her breast exposed with the unique exception of the painting studied in this work.   Puerto Rican art historians have speculated that this was a result of a posterior intervention.  Grazing angle visible images, as well as, infrared reflectography taken with Si- (940 nm) and InGaAs- (< 1.7 μm) based cameras and x-ray images of the painting were obtained in order to establish this possibility.  Images in the visible taken at a low grazing angle established the presence a paint overlayer in the suspect area.  Reflectance infrared images and transmission x-ray images confirmed their presence.  X-ray fluorescence analysis was performed in the intervened area and in similar chromatic fields elsewhere in the painting.  The obtained spectra indicate that the pigments used in the intervened area are the same as those used elsewhere in the painting.

2015-06-11 10.49.28Second, we will report on the application of Raman and X-ray fluorescence spectroscopy to the identification of pigments in pre-Columbian (250 A.C. – 600 D.C.) Caribbean ceramics.  The results shed light on a controversy among Caribbean archaeologists: one group argues that the pieces were produced by two different aborigine cultures (Huecoide and Saladoide) versus those who propose that they belong the same culture. Our results, particularly those derived from the study of white pigments in decorated ceramic sherds, supports the two-different-culture hypothesis as two distinct pigments is suggested: kaolinite and calcium carbonate.