UMSS22 Physical and Mathematical Sciences

Abstract: This project uses a custom polarimeter to measure the polarization of light we receive from stars. Most bright stars emit unpolarized radiation, so measuring non-zero polarization is significant. Even highly polarized stars only have polarizations around five percent. Polarized light from a star may mean 1) the star is actually a binary system, 2) the star has a significant magnetic field, or 3) the star has some other feature or variability that is atypical of the majority of bright stars. A polarimeter is used to measure polarization. As the Jordan Observatory did not have a polarimeter, the project began by designing and constructing an instrument to suit our purposes. The polarimeter needed to be small enough to fit unobtrusively on the telescope and have the precision necessary to measure stellar polarization. The polarimeter was designed, and parts were ordered for its construction. Once constructed, the polarimeter was used to collect data on a number of stars and other celestial objects. Code was written to work with the polarimeter. This code calculated polarization using the intensities of images taken at different orientations of the instrument. Stars with known negligible polarization and stars with known high polarizations were used to calibrate the polarimeter for any instrument polarization and check its accuracy. Then, stars with lesser known but still likely high polarizations were targeted. A few non-stellar objects were also targeted to test the capacity of the polarimeter. The polarimeter was paired with two different cameras to investigate their effect on instrument performance.

Isolation and Analysis of Glycosaminoglycans (GAGs) Using TEAB Auxiliary

Submission Type: Poster

Submission Category: Physical and Mathematical Sciences

Author(s):

Jinyoung Park

Matthew Brichacek

Undergraduate Student Presentation

Faculty Mentor: Matthew Brichacek

Abstract: Glycosaminoglycans (GAGs) are involved in biological processes such as stem cell differentiation, migration, and infections. GAGs serve a significant role in influencing the attachment and transmission of harmful pathogens in biological hosts. The current processes of isolating GAGs are challenging and inefficient due to the complexity in their structure. In this study, glycan auxiliary 2-thio(N-aminoethyl)benzamide (TEAB) auxiliary was synthesized (75% yield) and conjugated to natural hyaluronate (hyaluronic acid) polymers. The hyaluronic acid polymers were shortened using acid hydrolysis, conjugated with the TEAB-Zn auxiliary through reductive amination, and fractionated by size. The conjugated hyaluronic acid was analyzed by 1H NMR. From the analysis of the 100-hour aliquot, 97.2 mg of conjugated HA product was obtained, which contained an average of 24 HA units attached to the TEAB-Zn. The functionalized GAGs were then attached to a glass microscope slide (biological array) for further in-depth analysis.

Effect of Reducing Agent on Water-Stable Gold-aryl Nanoparticles

Submission Type: Poster

Submission Category: Physical and Mathematical Sciences

Author(s):

Everett Zuras

Ahmad Ahmad

Mitchell Bruce

Alice Bruce

Undergraduate Student Presentation

Faculty Mentor: Alice Bruce

Abstract: Metal nanoparticles are of interest to the scientific community for their unique physical and chemical properties. Gold-aryl nanoparticles (AuNPs-COOH) exhibit high catalytic activity due to their high surface-to-volume ratio. AuNPs-COOH are synthesized by the reduction of aryldiazonium gold(III) salts using a mild reducing agent such as sodium borohydride or 9-BBN in aqueous solution. This work focuses on the effect of the reducing agent on the size, properties, and catalytic ability of AuNPs-COOH. Varying the choice and the amount of reducing agent used in the preparation of AuNPs-COOH has been shown to have an inverse correlation with the size and a direct correlation with apparent rate constant (k app ) in the reduction of 4-nitrophenol (4-NPh) with NaBH 4 catalyzed by AuNPs-COOH. UV-Vis spectroscopy is used for both the estimation of nanoparticle size, and to follow the reduction of 4-NPh. IR spectroscopy is used to provide understanding as to the nature of the organic shell.

Examining the Impact of Question Order on Student Performance on Qualitative Physics Questions

Submission Type: Poster

Submission Category: Physical and Mathematical Sciences

Author(s):

Jaymie Pratl

MacKenzie Stetzer

Undergraduate Student Presentation

Faculty Mentor: MacKenzie Stetzer

Abstract: The order in which introductory-level physics review questions are presented to college students may affect their ability to engage in productive reasoning leading to the correct answer. In certain cases, the inclusion of a cueing question may potentially enhance student performance by providing a guide toward the appropriate problem-solving technique. Dual-process theories of reasoning suggest that order may not matter in other cases. Two question sequences were administered to introductory, calculus-based physics students on online participation-based homework assignments. The sequences were focused on the effects of frictional forces and on the concept of a closed-loop circuit. The question sets consisted of two multiple-choice questions and two short answer explanation fields, in which students provided explanations of their thought processes. The question order was randomized in a manner that some students viewed the cueing question first while others received the target question. If the sequences functioned as intended, it was hypothesized that students who viewed the cueing question first would be more likely to produce a correct answer on the target question, and students who received the target question first would be more likely to alter their original answer when given an opportunity to reflect on the consistency of their reasoning. Insight into the extent to which question sequencing may impact student performance may guide the development of instructional materials that target student reasoning.