Evolution of Mid-gap States and Residual 3-Dimensionality in La2−x_{2-x}Srx_xCuO4_4

We have carried out extensive first principles doping-dependent computations of angle-resolved photoemission (ARPES) intensities in La$_{2-x}$Sr$_x$CuO$_4$ (LSCO) over a wide range of binding energies. Intercell hopping and the associated 3-dimensionality, which is usually neglected in discussing cuprate physics, is shown to play a key role in shaping the ARPES spectra. Despite the obvious importance of strong coupling effects (e.g. the presence of a lower Hubbard band coexisting with mid-gap states in the doped insulator), we show that a number of salient features of the experimental ARPES spectra are captured to a surprisingly large extent when effects of $k_z$-dispersion are properly included in the analysis.Comment: 5 pages, 4 figure

Block Spin Ground State and 3-Dimensionality of (K,Tl)Fe1.6_{1.6}Se2_2

The magnetic properties and electronic structure of (K,Tl)y Fe1.6 Se2 is studied using first-principles calculations. The ground state is checkerboard antiferromagnetically coupled blocks of the minimal Fe4 squares, with a large block spin moment ~11.2{\mu}B . The magnetic interactions could be modelled with a simple spin model involving both the inter- and intra-block, as well as the n.n. and n.n.n. couplings. The calculations also suggest a metallic ground state except for y = 0.8 where a band gap ~400 - 550 meV opens, showing an antiferromagnetic insulator ground state for (K,Tl)0.8 Fe1.6 Se2 . The electronic structure of the metallic (K,Tl)y Fe1.6 Se2 is highly 3-dimensional with unique Fermi surface structure and topology. These features indicate that the Fe-vacancy ordering is crucial to the physical properties of (K,Tl)y Fe2-x Se2 .Comment: Magnetic coupling constants double checked, journal ref. adde

Background-oriented schlieren (BOS) for scramjet inlet-isolator investigation

Background-oriented Schlieren (BOS) technique is a recently invented non-intrusive flow diagnostic method which has yet to be fully explored in its capabilities. In this paper, BOS technique has been applied for investigating the general flow field characteristics inside a generic scramjet inlet-isolator with Mach 5 flow. The difficulty in finding the delicate balance between measurement sensitivity and measurement area image focusing has been demonstrated. The differences between direct cross-correlation (DCC) and Fast Fourier Transform (FFT) raw data processing algorithm have also been demonstrated. As an exploratory study of BOS capability, this paper found that BOS is simple yet robust enough to be used to visualize complex flow in a scramjet inlet in hypersonic flow. However, in this case its quantitative data can be strongly affected by 3-dimensionality thus obscuring the density value with significant errors

Fluctuations and massive separation in three-dimensional shock-wave/boundary-layer interactions

Shock-wave unsteadiness was observed in rapidly compressed supersonic turbulent boundary layer flows with significant separation. A Mach 2.85 shock-wave/turbulent boundary layer flow was set up over a series of cylinder-flare bodies in the High Reynolds Number Channel 1. The transition from fully attached to fully separated flow was studied using axisymmetric flares with increasing compression angles. In the second phase, the 30 deg flare was inclined relative to the cylinder axis, so that the effect on a separated flow of increasing 3 dimensionality could be observed. Two 3-D separated cases are examined. A simple conditional sampling technique is applied to the data to group them according to an associated shock position. Mean velocities and turbulent kinetic energies, computed from the conditionally samples data, are compared to those from the unsorted data and to computed values. Three basic questions were addressed: can conditional sampling be used to provide snapshots of the flow; are averaged turbulence quantities dominated by the bimodal nature of the interaction; and is the shock unsteadiness really important to computational accuracy

Diffusion map for clustering fMRI spatial maps extracted by independent component analysis

Functional magnetic resonance imaging (fMRI) produces data about activity inside the brain, from which spatial maps can be extracted by independent component analysis (ICA). In datasets, there are n spatial maps that contain p voxels. The number of voxels is very high compared to the number of analyzed spatial maps. Clustering of the spatial maps is usually based on correlation matrices. This usually works well, although such a similarity matrix inherently can explain only a certain amount of the total variance contained in the high-dimensional data where n is relatively small but p is large. For high-dimensional space, it is reasonable to perform dimensionality reduction before clustering. In this research, we used the recently developed diffusion map for dimensionality reduction in conjunction with spectral clustering. This research revealed that the diffusion map based clustering worked as well as the more traditional methods, and produced more compact clusters when needed.Comment: 6 pages. 8 figures. Copyright (c) 2013 IEEE. Published at 2013 IEEE International Workshop on Machine Learning for Signal Processin

Tactile animation

This creative project takes a look at a new method of approaching the study of animation through use of a new type of 3-dimensional zoetrope called the ellistrope. The ellistrope helps answer "the whys" that linger in the heads of new animators. As they look at the figures dance and come to life all at once while the ellistrope is spinning, they can study the figure from a variety of views all at once. They can concentrate on one angle, and then compare it to any other in an instant. The student now has the opportunity to hold a frame in their hands. This will help them grasp the concepts of 3-dimensionality, thinking in the round, and foreshortening, and not just seeing an image on the screen. By doing this they can further study and grasp the concepts of key poses and dynamic drawings. Being able to investigate what happens from many perspectives and in different tangible fragments provides an excellent learning tool not previously accessible.Department of ArtThesis (M.A.

Pattern Research Project: An Investigation of The Pattern And Printing Process - Marigold

2018 Pattern Research Project Emily Ballentine - Marigold The Pattern Research Project involves research and analysis of contemporary patterns found in the textiles and wallcoverings of the built interior environment. Patterns use motif, repetition, color, geometry, craft, technology, and space to communicate place, time, and concept. Through this research and analysis, built environments - their designers, occupants, construction, and context - can be better understood. Emily Ballentine, VCU Interior Design BFA 2021, selected the Marigold pattern for the 2018 Pattern Research Project. The text below is excerpted from the student’s work: “The sample of Marigold was screen-printed at Bradbury and Bradbury. Screen printing is a process that includes using a hand carved stencil for each layer represented. The printing table stretches 90 feet and is equipped with special knobs to adjust to the repeat of the pattern. A monofilament polyester screen covers and is tightly sealed to the artwork (the finished pattern that acts as a guide for where to place each stencil). Ink is pushed through the stencil using a squeege that runs up the surface, soaking the screen and then back down, scraping away access ink.”https://scholarscompass.vcu.edu/prp/1022/thumbnail.jp