Abstract Submitted for Presentation

Poster Presentation at the ADSE (Alliance for Diversity in Science and Engineering) Young Researchers' Conference at University of Maryland on September 16th 2017.

Anisyl Sulfanyl Methyl IsoCyanide (ASMIC): Rapid Construction of Heterocyclic Scaffolds

We have recently developed a versatile isocyanide core, termed Anisyl Sulfanyl Methyl IsoCyanide (ASMIC), that allows for the formation of stable secondary carbanions upon deprotonation. Application of ASMIC to the synthesis of a broad spectrum of heterocycles has been realized through our preliminary investigations. Introduction of different electrophiles such as nitriles, ketones, and esters leads to the rapid formation of imidazole, oxazoline and oxazole containing scaffolds. In-situ trapping readily gives the N- protected analogs. These scaffolds also present several points for further modification via deprotonation/alkylations, exchange and coupling reactions. The anisyl sulfanyl group incorporates orthogonality to the scaffold by providing both nucleophilic and electrophilic behavior based on the type of applied modification. Furthermore, we have demonstrated the decoration of these scaffolds in one or two pot reactions. This method will be further explored for the rapid construction of other heterocyclic scaffolds such as imidazopyridines and thioimidazole pyridines. We will also continue to investigate scaffold functionalization.

The Deccan Traps continental flood basalts erupted onto the Indian peninsula at ~66 Ma, extending from southern India to the border of Pakistan. Previous research has been lacking in precise, spatially referenced estimates of basalt flow volumes, a metric critical for accurately determining the amount of degassing that took place over the course of the eruptions and their subsequent environmental impact. The analytical functions of the mapping software ArcGIS were used to construct high-resolution volume estimates for individual sections of some of the northern regions of the Deccan, known as the Malwa Plateau and the Mandla Lobe. Our initial findings produced a combined volume of < 2400 km^3 for the whole of the Malwa. This estimate is much lower than previous estimates for total Deccan volume (~500,000 km^3), but the lava flows of this sub-region are much less laterally extensive than other regions further south. To complement the work being done in the north, we also used ArcGIS to digitally trace the boundaries of the 11 major chemostratographic formations in the main Deccan region south of the Malwa. These initial findings are promising, and suggest that Geographic Information Systems (GIS) can be a key tool for interpreting the architecture of large igneous provinces (LIPs) like the Deccan Traps. We plan to integrate rock core and stratigraphic data into updated volume estimates to determine average eruption rates for individual Deccan flow formations. The work presented here will have significant consequences in understanding the pattern of gas release to the atmosphere resulting from the Deccan volcanic eruptions, and the role they may have played in the end-Cretaceous extinction and post-extinction ecosystem recovery.

I presented at the Army Research Lab Summer Symposium, Aberdeen Proving Ground. Presentation talk.

Abstract:
Since 1983, the Army has mandated that all deployed equipment be coated with chemical agent resistant coatings (CARCs). Composed of a two layer system, a primer and a top coat, CARCs are engineered to provide maximum protection against environmental conditions, corrosion, and chemical agents. Currently, however, few—if any—non-destructive evaluation (NDE) techniques exist to determine the performance of either the protective coating or the material underneath the coating. Oftentimes, it is necessary to completely remove the CARC paint using caustic and harmful paint strippers before the material under the paint can be inspected. To this end, time domain terahertz spectroscopy is proposed as a method capable of non-destructively detecting the onset of corrosion under CARC paints. More penetrating than visible or infrared radiation but less harmful than high energy, ionizing, x-ray radiation, terahertz occupies a niche in NDE techniques. Here, terahertz spectroscopy is shown to reliably identify corrosion under a variety of CARC systems and on different materials. Further terahertz spectroscopy provides imaging capabilities that allow for unique characterization of paint systems.

Interpolatory Hermite Subdivision Scheme of Manifold-Valued Data 
Yilin Yang, Drexel University, Class of 2017 
Thomas Yu, Professor, Drexel University 

Subdivision method is a special kind of multiscale method for interpolation and approximation, which defines a smooth curve or surface as the limit of a sequence of successive refinements. Now subdivision for surface modeling is regularly used in movie production, and is considered to be a core technology in game engines. Our research focuses on the regularity and approximation order properties of subdivision methods for manifold-valued data, which has important applications in many subjects such as motion planning and diffusion tensor imaging. Applying differential geometry ideas, we adapt the Hermite interpolation method to data on manifolds, called “interpolatory Hermite subdivision scheme”; and we observe that the regularity and approximation order of the method in the linear case is preserved in this extension to manifolds without being obstructed by the curvature. Finally using the technique of proximity conditions, we analyze that the interpolatory Hermite subdivision scheme gets full smoothness equivalence and approximation order equivalence for manifold-valued data.

Interpolatory Hermite Subdivision Scheme of Manifold-Valued Data
Yilin Yang, Drexel University, Class of 2017
Thomas Yu, Professor, Drexel University

Subdivision method is a special kind of multiscale method for interpolation and approximation, which defines a smooth curve or surface as the limit of a sequence of successive refinements. Now subdivision for surface modeling is regularly used in movie production, and is considered to be a core technology in game engines. Our research focuses on the regularity and approximation order properties of subdivision methods for manifold-valued data, which has important applications in many subjects such as motion planning and diffusion tensor imaging. Applying differential geometry ideas, we adapt the Hermite interpolation method to data on manifolds, called “interpolatory Hermite subdivision scheme”; and we observe that the regularity and approximation order of the method in the linear case is preserved in this extension to manifolds without being obstructed by the curvature. Finally using the technique of proximity conditions, we analyze that the interpolatory Hermite subdivision scheme gets full smoothness equivalence and approximation order equivalence for manifold-valued data.

Construction of a Solution to Horn’s Conjecture via Inverse Problem of Band Matrices
Yilin Yang, Drexel University, Class of 2017  

Hermitian matrices have a wide range of applications in physics and engineering, and are closely and non-trivially linked with many other mathematical objects. A. Horn's problem is a long-standing mathematics problem that asks to characterize eigenvalues of Hermitian matrices A, B and A+B. Although it was solved in the beginning of this century, the proof requires a heavy machine outside of linear algebra in which the original problem stands and the construction of A and B with valid spectral data remains unclear. In this research, we make a connection between A. Horn's problem and another classical linear algebra problem, inverse problem of band matrices, via the rank of A and bandwidth of B. This connection gives an efficient way to build a solution for A. Horn's problem with given spectral data. In the base case where A has rank 1, we show how the Hermitian matrices A, B and A+B with given sets of eigenvalues are constructed through recovering B from the eigenvalues of B and the eigenvalues of the submatrix obtained by removing the first row and column of B.

Conference: Stanford Research Conference
Location: Stanford University, Palo Alto, California
Dates: April 15-17, 2016
Presentation: poster presentation
Funding awarded by: Office of Undergraduate Research

Title: Design and Development of a Right Ventricular Assist Device
Abstract: Congestive heart failure (CHF) is a debilitating disease that affects millions of patients in the United States with acquired or congenital heart disease. The current treatment paradigm for CHF includes cardiac drugs, heart transplantation, and ventricular assist devices (VADs) that provide temporary bridge-to-transplant and long-term mechanical circulatory assistance to patients with left-sided or right-sided heart failure. Although the preponderance of CHF patients have left ventricular failure, a significant percentage of these patients also have ineffective right ventricles. Since few devices or therapeutic alternatives exist for patients who have failing or severely dysfunctional right ventricles, we are developing a novel right-sided VAD, or RVAD. Building upon a prior design, we improved the pump performance and geometry to accommodate the motor-suspension system. The geometry of the RVAD is more compact than that of the original VAD and features an impeller that is levitated using a novel magnetic suspension system. The target design of the RVAD is to generate blood flow rates of 4-7 L/ min for pressure rises of 10-30 mmHg over rotational speeds of 7,000-13,000 RPM. Numerical simulations of the RVAD were performed using ANSYS CFX such that we directly compared the performance of the improved RVAD model to initial RVAD designs. Computational studies showed that the RVAD achieved the target design and maintained hydraulic performance despite being more than 40% smaller than the RVAD. An assessment of blood cell damage also revealed a low likelihood of trauma with damage indices below 2%. These results support the continued development of this new RVAD for the treatment of right ventricular failure.      

The BLAST-TNG experiment is chosen to fly in December, the eve of the Antarctic summer; during this time of year in the South Pole, constant sunlight is unavoidable. While BLAST-TNG benefits from such conditions since it is powered by solar panels, the abundance of sunlight concurrently puts the efficiency of its star cameras at extreme risk. Although the cameras need to absorb photons from stars in front of them, the sun's immense power would otherwise blind the cameras with unnecessary light; the star camera baffles were designed to block all such light.

Networks In traditional wireless networks, omnidirectional antennas are used for transmission and reception. While this increases the likelihood of a successful link, it also increases the likelihood that one transmission will interfere with another and reduce the utility of the network. In order to increase the performance of the network, reconfigurable antennas that are capable of beam steering are being utilized in directional routing schemes. Compared with traditional routing schemes, directional routing allows nodes to transmit energy only towards the direction of the intended receiver. Therefore, with a more concentrated energy distribution, directional antennas greatly enhance network capacity and achieve a higher signal to noise ratio while reducing the interference on other nodes. When visualizing these systems, traditional network visualization tools do not take into account antenna configuration. To solve this issue, routing tables and antenna configuration information for the network was gathered from the Netlink Protocol Library Suite (libnl) in Linux, and is then fed into MATLAB for processing. MATLAB was used to create a tool to both visualize the network connectivity graph while including some notion of the antenna configuration. The tool shows the shortest paths for signal transmissions by calculating the lowest cost routing over each antenna configuration.