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Colloquium

In this Section
 

Fall 2016

 
Department of Physics
Clarkson University
Student Seminar

Thursday, August 11, 2016
11:00 AM
B. Snell 177

Prof. Jan Halamek
Department of Chemistry
SUNY Albany

will speak on

Recent advances in forensic serology


Biomarker analysis is a long standing discipline in forensic science, for instance, the analysis of blood for the presence of various substances can be performed along with DNA for identification purposes. The forensic science field has developed rapidly over the years, however, the methods that are currently implemented still need improvement. Most of the modern and routinely used forensic science techniques require the collection of the sample at the crime scene, followed by transportation to a laboratory facility for its analysis. Crimes are usually committed in high volumes, thus, improvement to these analyses is of great necessity. The backlog in the analysis of serology samples has been recognized and addressed by the NIJ, but major improvements are still required, as full-scale investigations can still take weeks or even months.

The research presented here addresses this situation by introducing the use of bio affinity-based assays for quick and straightforward on-site analyses of blood and fingerprint samples. These enzyme cascades use substrates that are naturally present in the samples in order to identify various traits of the sample originators such as age, gender, ethnicity, and general health conditions. Because only miniscule amounts of enzymes and substrates are necessary, this method requires only very small amounts of samples. Furthermore, the bio-affinity based cascades are remarkably versatile and can be adjusted for the analysis of a wide range of substrates for the discernment of different physical traits.

This approach has the potential to move the strictly laboratory-based analyses to rapid on-site analyses that do not require specialized laboratory training. This could lead to the revolution of the field of forensic science and result in the acceleration of many criminal investigations.

 
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Spring 2016
Department of Physics
Clarkson University
Student Seminar
 
Friday, April 1, 2016
3:30 PM
B. Snell 177

William Whitney
Department of Physics
Clarkson University
 
will speak on

 

Identifying Optical Aberrations in Light-sheet Microscopy Sample Mounting

The symbiosis between biology and physics has developed rapidly in recent decades, particularly in the area of microscopy.  However, living systems still present numerous challenges to high quality imaging, which is in part due to the scale of intact organisms.  Recently, light-sheet microscopy has emerged as a valuable tool for studying small organisms with excellent space and time resolution. This talk describes our work to design and build a state-of-the-art lightsheet microscope, including several of the major challenges encountered.  We will describe in detail the optical aberrations that arise from common approaches used to mount large samples for high-resolution imaging. These results are significant in the context of our work to probe the mechanics of the endothelial glycocalyx, a biofunctional polymer brush that lines the wall of blood essels.  These experiments require us to track the motion of the proteins and particle with high precision, which is challenging in the presence of significant optical aberrations.  We aim to use this investigation of the optical aberrations in light-sheet sample mounting as a foundation for the adoption of adaptive aberration correction methods in the future.

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Department of Physics
Clarkson University
Student Seminar
 
Friday, February 26, 2016
3:30 PM
B. Snell 177
 
Han Yan
Department of Physics
Clarkson University

 
will speak on
Random Sequential Adsorption on Imprecise Lattice Substrates

 
Irreversible random sequential adsorption (RSA) model describes a process of deposition of sequentially arriving objects on a surface, with the exclusion “no overlap” condition. Frequently, RSA is studied assuming lattice ordering of the allowed attachment sites on the surface. With the advent of nanotechnology, lattice patterns can be prepared on substrates, but these are absolutely precise. Here we consider deposition of segments on a line. In our model, lattice points on the line were replaced with small “attachment regions” to simulate imprecise adsorption. Centers of line segments transported to the surface can attached only in these regions, if there is no overlap with previously deposited segments. The jammed-state properties and time dependent coverage of the model RSA kinetics were studied. Numerical simulation and some alytical results were obtained indicating new striking properties of the absorption kinetics on imprecise substrates
 
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Department of Physics
Clarkson University
Student Seminar
 
Friday, March 11, 2016
3:30 PM
B. Snell 177
 
Sergii Domanskyi
Department of Physics
Clarkson University
 
 
will speak on
 
 
 

Non-Adiabatic Molecular Dynamics in Multi-Crossing Systems

 

Non-adiabatic molecular dynamics is important in the study of many photophysical and photochemical reactions. Various approximations are used to calculate transitions between electronic states in large systems such as real molecules. Many of the approaches either have the desired accuracy only in certain scenarios or lead to high computational costs.

The novel accelerated Semi-classical Monte Carlo technique based on recently developed algorithm [Gorshkov et al., Nat. Commun. 4, 2144 (2013), White et al., J. Chem. Phys. 141, 184101 (2014)], has features of Surface hopping methods but accounts for quantum coherence effects, while neglecting some nuclear quantum effects such as tunneling, etc. We apply it to the test problems which demonstrate breakdown of common approximations, comparing the solution to that of existing approaches such as Ehrenfest method, Fewest Switches Surface Hopping method and exact quantum solution.

 
 
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Department of Physics
Clarkson University
Student Seminar
 
Friday, February 26, 2016
3:30 PM
B. Snell 177
 
Han Yan
Department of Physics
Clarkson University
 
 
will speak on
 
 
Random Sequential Adsorption on Imprecise Lattice Substrates
 
 
 
Irreversible random sequential adsorption (RSA) model describes a process of deposition of sequentially arriving objects on a surface, with the exclusion “no overlap” condition. Frequently, RSA is studied assuming lattice ordering of the allowed attachment sites on the surface. With the advent of nanotechnology, lattice patterns can be prepared on substrates, but these are absolutely precise. Here we consider deposition of segments on a line. In our model, lattice points on the line were replaced with small “attachment regions” to simulate imprecise adsorption. Centers of line segments transported to the surface can attached only in these regions, if there is no overlap with previously deposited segments. The jammed-state properties and time dependent coverage of the model RSA kinetics were studied. Numerical simulation and some alytical results were obtained indicating new striking properties of the absorption kinetics on imprecise substrates
 
 
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Department of Physics
Clarkson University
Student Seminar
 
Friday, February 19, 2016
3:30 PM
B. Snell 177
 

Michael Turk
Department of Physics
Clarkson University

will speak on

 Tribo-electrochemical characterization of a slurry composition designed to minimize dissolution and galvanic corrosion during
chemical mechanicalplanarization of C u-Ru interconnect structures

 

Ruthenium is a nontraditional barrier material considered for copper-interconnects in the sub-22 nm technology nodes. The chemical mechanical planarization (CMP) schemes used to manufacture these devices involve complex surface chemistries of Ru and Cu. Specifically, the strict requirement of defect-control while maintaining material removal by precisely regulated tribo-corrosion complicates the designs of the CMP slurries needed to process these systems. Since Ru is electrochemically more noble than Cu, the surface regions of Cu assembled in contact with Ru tend to develop defects due to galvanic corrosion in the CMP environment. The present report explores an alkaline slurry formulation aimed at reducing galvanic corrosion effects in chemically controlled low-pressure CMP of Ru. This slurry uses sodium percarbonate, sodium bicarbonate, benzotriazole and colloidal silica as an oxidizer, a complexing additive, a dissolution inhibitor, and an abrasive agent, respectively. The CMP specific functions of the slurry components are characterized in the tribo-electro-analytical approach by using voltammetry and open circuit potential measurements in the presence as well as in the absence of surface abrasion, both with and without the inclusion of colloidal SiO2 abrasives.  The results indicate the reaction mechanisms responsible for supporting material removal and corrosion suppression. Impedance spectroscopy performed under steady state conditions further clarifies the roles of these CMP reactions.

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Department of Physics
Clarkson University
Student Seminar
 
Friday, January 22, 2016
3:30 PM
B. Snell 177
 
 
David Simpson
Department of Physics
Clarkson University

 

will speak on
 
 
Investigation of a Gold Anode for Application in Direct Alkaline Glycerol Fuel Cells
 
 
Alkaline alcohol fuel cells (DAAFCs) represent a rapidly developing branch of the alternative energy technologies. Cost effective fuels, often available as biodiesel derivatives, are directly used in these cells to generate electricity by electro-catalytic reactions (as opposed to going through intermediate steps of generating hydrogen as a fuel). Thus the fuel and oxygen are directly oxidized and reduced at the anode and the cathode of the cell, respectively, without generating pollutant byproducts. The fuel is supplied from a refillable reservoir, as opposed to the case of a battery, where the active material of the device itself serves as the energy source and requires electrochemical reactions to recharge. Consequently, the supply of energy is continuous in a fuel cell as long as the fuel is available.

Due to its low cost and abundance, glycerol is a fuel of particular interest for DAAFCs. Electro-oxidation of glycerol at the anode surface is the driving factor for energy conversion in a direct alkaline glycerol fuel cell (DAGFC). In this presentation, we examine the electrochemical performance of a gold catalyst anode for a DAGFC in a half-cell configuration by using stationary- and rotating disc electrode voltammetry techniques. The interfacial reactions and their products are identified by measuring the number of electrons released during the intermediate steps. By comparing the findings for stationary and rotating electrodes, it is shown that, convective mass transport is critical to maintaining efficient progression of the consecutive oxidation steps of glycerol.

 
 
 
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