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Full-Text Articles in Physical Sciences and Mathematics

Phthalate Plasticizers Covalently Linked To Pvc Via Copper-Free Or Copper Catalyzed Axide-Alkyne Cycloadditions, Aruna Earla, Li Longbo, Philip Costanzo, Rebecca Braslau Dec 2016

Phthalate Plasticizers Covalently Linked To Pvc Via Copper-Free Or Copper Catalyzed Axide-Alkyne Cycloadditions, Aruna Earla, Li Longbo, Philip Costanzo, Rebecca Braslau

Chemistry and Biochemistry

Plasticization of PVC was carried out by covalently linking phthalate derivatives via copper-free (thermal) or copper catalyzed azide-alkyne cycloadditions. Di(2-ethylhexyl) phthalate derivatives (DEHP-ether and DEHP-ester) were synthesized and appended to PVC at two different densities. The glass transition temperatures of the modified PVC decreased with increasing content of plasticizer. PVC-DEHP-ether gave lower glass transition temperatures than PVC-DEHP-ester, reflecting the enhanced flexibility of the ether versus ester linker.


An Examination Of Student Outcomes In Studio Chemistry, Alan L. Kiste, Gregory E. Scott, Jesse Paul Bukenberger, Miles Markmann, Jennifer Moore Dec 2016

An Examination Of Student Outcomes In Studio Chemistry, Alan L. Kiste, Gregory E. Scott, Jesse Paul Bukenberger, Miles Markmann, Jennifer Moore

Chemistry and Biochemistry

Twenty years ago, a major curriculum revision at a large, comprehensive university in the Western United States led to the implementation of an integrated lecture/laboratory (studio) experience for our engineering students taking general chemistry. Based on these twenty years of experience, construction of four purpose-built studio classrooms to house the majority of the remaining general chemistry courses was completed in 2013. A detailed study of the effects of the entire ecology of the studio experience on student success was initiated at that time. Data from content knowledge pre- and post-tests, learning attitudes surveys, and student course evaluations show positive effects …


Atomic Tiles: Manipulative Resources For Exploring Bonding And Molecular Structure, Alan L. Kiste, Rebecca G. Hooper, Gregory E. Scott, Seth Bush Oct 2016

Atomic Tiles: Manipulative Resources For Exploring Bonding And Molecular Structure, Alan L. Kiste, Rebecca G. Hooper, Gregory E. Scott, Seth Bush

Chemistry and Biochemistry

A simple manipulative resource, Atomic Tiles, is described for scaffolding the learning of Lewis structures without using algorithmic, rule-based methods of drawing. Students use Atomic Tiles to (1) create models of bonding that lead to drawing Lewis structures, (2) use the structures they create to infer patterns required for rational structures and common organic functional groups, (3) translate between Lewis structures and molecular models, and (4) use molecular models to identify isomers.


Effect Of Surface Treatment On Liquid Adhesion Inside 3-D Structures, Madani A. Khan, Jeffrey Alston, Andrew Guenthner, Jacob Zavala Oct 2016

Effect Of Surface Treatment On Liquid Adhesion Inside 3-D Structures, Madani A. Khan, Jeffrey Alston, Andrew Guenthner, Jacob Zavala

STAR Program Research Presentations

This study explores the relationship between chemical surface treatments on the interior of glass tubes and their resistance to fluid flow. By treating the interior of the tubes with functional silanes we can decrease or increase the interaction of the tube walls with the fluid column, which translates to changes in fluid column height for a given pressure differential. Resistance to fluid flow is quantified by using the tubes as integral parts of a barometric pressure column and measuring the changes in column height as the fluid is pulled into the tube by a set pressure differential. The barometric pressure …


Characterization Of S-Swcnt/Pf-Pd Dispersions And Networks, Tamara N. El-Hayek Ms., Jeffrey Blackburn, Andrew Ferguson, Tammy Pheuphong Oct 2016

Characterization Of S-Swcnt/Pf-Pd Dispersions And Networks, Tamara N. El-Hayek Ms., Jeffrey Blackburn, Andrew Ferguson, Tammy Pheuphong

STAR Program Research Presentations

Single-Walled Carbon Nanotubes (SWCNTs) are being investigated for their use in a wide variety of renewable energy applications. Their unique physical properties contribute to desirable traits such as a high carrier mobility, strong optical absorption and tunable electronic band gap. Unfortunately, due to variability in certain parameters, SWCNTs are limited in their application. The major drawback is that SWCNTs are variable in size and type and typical synthetic methods are not selective. As a result, selective methods must be developed in order to sort these tubes and extract those which are desirable for a particular application. Though there are several …


Gc Verification Of The Spacecraft Atmosphere Monitor, Jessica S. Castro, Richard D. Kidd, Jeffrey D. Hein Sep 2016

Gc Verification Of The Spacecraft Atmosphere Monitor, Jessica S. Castro, Richard D. Kidd, Jeffrey D. Hein

STAR Program Research Presentations

International Space Station crew members face the unique challenge of maintaining air quality due to the volatile organic compounds (VOCs) that have the potential to accumulate at unsafe levels. The Spacecraft Atmosphere Monitor (SAM) is a miniature gas chromatograph/mass spectrometer (GCMS) designed to measure major constituents (such as N2, O2 and CO2) and trace VOCs within the cabin of the spacecraft. The gas chromatograph is responsible for separating the sample into its components in order to be characterized. The oven of the gas chromatograph must reach a temperature of 150°C in order to heat constituents …


Density Functional Theory Based Electrolyte Design Formulation For Lithium-Sulfur Batteries, Cynthia Ly, Carolyn Sturges, Vijay Murugesan Aug 2016

Density Functional Theory Based Electrolyte Design Formulation For Lithium-Sulfur Batteries, Cynthia Ly, Carolyn Sturges, Vijay Murugesan

STAR Program Research Presentations

Lithium-ion (Li-ion) batteries are commonly used in portable electronics such as cellphones and laptops. Most Li-ion batteries operate on intercalation principle with typical theoretical specific energy of 400-600 (Wh/Kg). There is great scientific interest in lithium-sulfur (Li-S) batteries as a possible successor of traditional Li-ion batteries because Li-S holds the potential of being a very powerful (1550 Wh/kg theoretical specific energy) yet very cost-efficient battery (due the abundance and inexpensiveness of sulfur). However, one major problem in Li-S battery research is the polysulfide “shuttle phenomenon”, which is the shuttling of polysulfide species due to the dissolution of sulfide from the …


Calculating The Energy Barriers Required To Join Metal-Organic Framework Synthesis Intermediates With Non-Equilibrium Molecular Simulation, Marcus A. Tubbs, David Cantu, Roger Rousseau, Vassiliki-Alexandra Glezakou Aug 2016

Calculating The Energy Barriers Required To Join Metal-Organic Framework Synthesis Intermediates With Non-Equilibrium Molecular Simulation, Marcus A. Tubbs, David Cantu, Roger Rousseau, Vassiliki-Alexandra Glezakou

STAR Program Research Presentations

Metal organic frameworks are synthetic porous materials with great capacity for adsorption of carbon dioxide and methane. They chemically appear as a chain-link fence with nodes of metal connected by organic linkers. The pores between the nodes define the characteristics of the material, allowing gas particles of specific size to pass through while blocking larger particulates. While there has been success in synthesizing small amounts of metal organic frameworks, the mechanistic details behind their assembly remain unknown. Understanding the synthesis mechanism is necessary to understand the kinetics involved and be able to produce this useful material on an industrial scale. …


Using In Situ Liquid Single Photon Ionization Mass Spectrometry (Spi-Ms) To Probe Lithium Polysulfide Electrolyte In Motion, Aala M. Al Hasan, Jiachao Yu, Juan Yao, Vijayakumar Murugesan, Manjula Nandasiri, Xiao-Ying Yu Aug 2016

Using In Situ Liquid Single Photon Ionization Mass Spectrometry (Spi-Ms) To Probe Lithium Polysulfide Electrolyte In Motion, Aala M. Al Hasan, Jiachao Yu, Juan Yao, Vijayakumar Murugesan, Manjula Nandasiri, Xiao-Ying Yu

STAR Program Research Presentations

The solid-liquid (s-l) interface is the most common interface encountered in electrochemical systems. The s-l interface has wide applications in energy storage, catalysis, and material sciences. In situ studies of chemical reactions taking place on the s-l interfaces can further our understanding of electron transfer and link to real-world device functions under challenging conditions. Direct probing of the solid electrode and liquid electrolyte interface has been realized using a vacuum compatible electrochemical microfluidic reactor, system for analysis at the liquid vacuum interface (SALVI) with time-of-flight secondary ion mass spectrometry (ToF-SIMS). Most recently, the electrochemical version of SALVI was integrated to …


Comparative Analysis Of In Situ Fibronectin Using Tof-Sims, Spi-Ms, And Dropdesi-Ms In A Microfluidic Reactor, Shannon Fasing, Xiao-Ying Yu, Juan Yao, Jiachao Yu Aug 2016

Comparative Analysis Of In Situ Fibronectin Using Tof-Sims, Spi-Ms, And Dropdesi-Ms In A Microfluidic Reactor, Shannon Fasing, Xiao-Ying Yu, Juan Yao, Jiachao Yu

STAR Program Research Presentations

Fibronectin is an important biomolecule due to its role in cell differentiation, growth, kinesis, and adhesion. Such biological responses are mediated through membrane recognition and signaling; where fibronectin is found. Studying the outer molecular surface of fibronectin allows deeper insight into the microbiological reactions that occur during these processes. In situ mass spectrometry analysis in aqueous solution accurately represents fibronectin’s chemical components, made possible by a vacuum compatible microfluidic reactor, SALVI (System for Analysis at the Liquid Vacuum Interface). SALVI was paired with the analytical tools: time-of-flight secondary ion mass spectrometer (ToF-SIMS), single photon ionization mass spectrometer (SPI-MS) and drop …


The Effects Of Rain On Elemental Transport In Soils, Laura Schoenfeld Jan 2016

The Effects Of Rain On Elemental Transport In Soils, Laura Schoenfeld

STAR Program Research Presentations

Mini Landscape Evolution Observatory (miniLEO) is a model landscape slope composed of granular basalt used to conduct small scale experiments to more clearly understand how elemental transport occurs during simulated rain events. For this experiment, rain events occurred three times a day in two hour increments at a rate of 30 mm/hr for 14 days to determine if exchangeable ions and target elements dissolve over time. An auto sampler collected the waterseepage every half hour at the bottom of the slope of miniLEO. Each seepage sample was tested or the amount of elements present in solution using ion chromatography and …


Probing The Transport Properties Of Chemically-Doped Single-Walled Carbon Nantotube Polymer Composites, Tammy Pheuphong, Tamara El-Hayek, Jeffrey Blackburn, Andrew Ferguson Jan 2016

Probing The Transport Properties Of Chemically-Doped Single-Walled Carbon Nantotube Polymer Composites, Tammy Pheuphong, Tamara El-Hayek, Jeffrey Blackburn, Andrew Ferguson

STAR Program Research Presentations

Thermoelectric (TE) materials are used to convert waste heat into electrical power. Semiconducting single-walled carbon nanotubes (s-SWCNT) have great potential to be used in thermoelectric devices, either on their own or in composites with conducting polymers. Certain polymers can selectively extract s-SWCNT from raw carbon nanotube soot (containing impurities such as metallic SWCNT, amorphous carbon, metal catalysts particles), but most of these polymers (e.g. polyfluorenes) are electrical insulators, rendering them inefficient in TE nanocomposites. On the other hand, conducting polymers, such as poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), have been used in efficient TE nanocomposites, but have never been rationally designed with …


Effects Of Surface Coatings On Crystalization Of Calcium Sulfate, Shawn Pj Kirby, Josiah Reams, Kamran Ghiassi, Jeffrey Alston Jan 2016

Effects Of Surface Coatings On Crystalization Of Calcium Sulfate, Shawn Pj Kirby, Josiah Reams, Kamran Ghiassi, Jeffrey Alston

STAR Program Research Presentations

Deposits from hard water can be problematic as they can form scaling on boilers and cooling towers. Scaling can reduce thermal efficiency. Coatings can be used to prevent mineral fouling by changing the surface energy. Some deposits have inverse solubility; such as calcium sulfate. This means that as temperature rises, they become less soluble and can crystallize out of solution. Calcium sulfate is often found in hard water. Crystalization tests were done to determine how coatings such as various POSS (Polyhedral oligomeric silsesquioxane) compounds acted as nucleating surfaces for calcium sulfate. POSS compounds were tested in particular because they …