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---
title: Academic Achievements
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description: A list of various publications, presentations and posters that I've given in the name of academia, including abstracts, links to proof that I did them, as well as full-text links when available.
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imageUrl: /img/library.jpg
blurImageUrl: /img/library_blur.jpg
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motto: Academic Publications and Presentations
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imageTitle: University of Idaho Library
imageDescription: Personally, I preferred the Owen Library in Pullman seven miles west
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---
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<!-- Thesis -->
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< dl >
< dt > Polyoxometalate Incorporation and Effects on Proton Transport in
Hydrogel Polymers< / dt >
< dd >
A Thesis Presented for the Degree of Master of Science of Chemical
Engineering in the University of Idaho by Thomas Allen Christensen II
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Major Professor: James G. Moberly, Ph.D.
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Committee Members: Kristopher Waynant, Ph.D.; Mark Roll, Ph.D.
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August 2020
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< a data-toggle = "collapse" data-target = "#thesis-abstract" role = "button" > Abstract < span class = "caret" > < / span > < / a >
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< a href = "https://www.proquest.com/dissertations-theses/polyoxometalate-incorporation-effects-on-proton/docview/2502214356/se-2" > < i class = "fas fa-file-alt" > < / i >   Full Text< / a >
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< div class = "collapse" id = "thesis-abstract" >
< p class = "font-serif" >
Polyoxometalate clusters embedded into hydrogel biobeads may be able to solve
the challenges posed by free proton generation during remediation of
trichloroethylene by acting as buffers and reducing protons to hydrogen gas. In
this thesis, the challenges posed by systems that contain both diffusion and
reaction processes for protons are considered mathematically, and a computer
simulation to was developed to prove the relationship between diaphragm cell lag
period and reactive capabilities of membranes. Two polyoxometalate compounds,
sodium decavanadate and alumina sulfate, were successfully incorporated into a
poly(vinyl alcohol) hydrogel membrane, and the diffusivity changes associated
with each compound was determined. It was found that the diffusivity of protons
through an unmodified 10% w/v poly(vinyl alcohol) membrane was 1.76 ×
10< sup > -5< / sup > cm< sup > 2< / sup > s< sup > -1< / sup > , the diffusivity through a 10%/2%
w/w/v poly(vinyl alcohol)/sodium decavanadate membrane was 3.10 × 10< sup > -6< / sup >
cm< sup > 2< / sup > s< sup > -1< / sup > , and the diffusivity through a 10%/2% w/w/v
poly(vinyl alcohol)/alumina sulfate membrane was 3.32 × 10< sup > -7< / sup >
cm< sup > 2< / sup > s< sup > -1< / sup > . Through analysis of the diaphragm cell lag
period, it was found the incorporation of sodium decavanadate did not increase
the reactivity of a poly(vinyl alcohol) hydrogel, and incorporation of alumina
sulfate lowered the reactivity. These results indicate that polyoxometalate
integration into hydrogel membranes is feasible, but does not provide any
advantage to a bioremediation scenario.
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<!-- Rumen metagenomics -->
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< dl >
< dt > Metagenomic analysis of rumen populations in week-old calves as
altered by maternal late gestational nutrition and mode of delivery< / dt >
< dd >
T. A. Christensen II, K.J. Austin, K. M. Cammack, and H. C. Cunningham-Hollinger
< br / >
Westion Section American Society of Animal Science Annual Meeting ● Boise, ID ● June 12, 2019
< br / >
1< sup > st< / sup > Place Undergraduate Poster Competition
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< a data-toggle = "collapse" data-target = "#metagenomics-abstract" role = "button" > Abstract < span
class="caret">< / span > < / a >
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< a href = "/blob/metagenomics_analysis_of_rumen_populations.pdf" > < i class = "fas fa-chart-pie" > < / i >   Full Text< / a >
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< div class = "collapse" id = "metagenomics-abstract" >
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< p class = "font-serif" > Early colonization of the rumen microbiome is critical to host health and long term
performance. Factors that influence early colonization include maternal factors such as gestational
nutrition and mode of delivery. Therefore, we hypothesized that late gestational nutrition and mode of
delivery would influence the calf rumen microbiome. Our objectives were to determine if nutrient
restriction during late gestation alters the calf rumen microbiome and determine if ruminal microbiome
composition differs in calves born vaginally versus caesarean. Late gestating Angus cows were randomly
allocated to one of three treatment groups: control (< b > CON< / b > ; n = 6), caesarean section (< b > CS< / b > ; n
= 4), and nutrient restricted (< b > NR< / b > ; n = 5), where CON were fed DDGS and hay to meet NRC
requirements and calved naturally; CS were fed similarly to CON and calves were born via caesarean
section; and NR were fed at a level to reduce BCS by 1.5-2.0 points over the last trimester compared to
CON and calved naturally. Rumen fluid was collected via oral lavage prior to partition from cows and at
d 7 from calves. Microbial DNA was isolated from the rumen fluid and metagenomic shotgun sequencing was
performed using the Illumina HiSeq 2500 platform. Sequence data were analyzed using Metaxa2 for
taxonomic assignment followed by QIIME1 and QIIME2 to determine differential abundance and alpha- and
beta-diversity differences. There were no significant differences in alpha-diversity as measured by
shannon index across treatment groups for cows (< em > P< / em > = 0.239), but there were significant
differences for calves (< em > P< / em > = 0.015). Similarly, there were no significant differences in
beta-diversity as measured by the bray-curtis dissimilarity matrix for cows (< em > P< / em > = 0.059), but
there were significant differences for calves (< em > P< / em > = 0.007). Alpha-diversity differed (< em > P< / em >
< 0.001 ) between cows and calves , with cows having increased species richness compared to calves .
Beta-diversity also differed (< em > P< / em > = 0.001) between cows and calves. At total of 410 taxa were
differentially abundant (< em > P< / em >
< 0.01 ) between cows and calves . These results suggest that the mature rumen microbiome of cows is
able to withstand changes in feed intake, however the calf microbiome is susceptible to
alteration by maternal factors. These data also suggest that there may be opportunities to
develop management strategies during late gestation that influence calf health and performance
long-term.< / p >
< p > < b > Key words< / b > : gestation, metagenomics, microbiome, rumen< / p >
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< / div >
< / dd >
< hr / >
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<!-- ChemE Car -->
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< dt > The ChemE Car that Cud: Entry and Documentation Packet to AIChE ChemE Car Contest< / dt >
< dd >
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Thomas Christensen II, Andrew Halverson, Kennedee True, Seth Messick, Amanda Christensen, Caleb Richmond,
Alexander Brown, & Jake Maksin with Dr. David Bagley
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< br / >
Rocky Mountain Regional AIChE Student Conference ● Golden, CO ● April 6, 2019
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2< sup > nd< / sup > Place Poster Competition ● 7< sup > th< / sup > Place Performance Competition
< br / >
< a data-toggle = "collapse" data-target = "#cheme-car" role = "button" > Abstract < span class = "caret" > < / span > < / a >
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< a href = "https://hdl.handle.net/20.500.11919/3817" > < i class = "fas fa-file-alt" > < / i >   Full Text< / a >
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< div class = "collapse" id = "cheme-car" >
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< p class = "font-serif" > The ChemE Car That Cud showcases Wyoming’ s dominant industries of agriculture and
mining by utilizing rumen fluid from a cannulated beef cow to generate hydrogen to be used in a hydrogen
fuel cell and radioactive cesium, a byproduct of uranium that is often obtained from Wyoming’ s mines, to
time the car’ s stop. The concentration of cesium-137 source is measured using the radioactive decay of
cesium shielded by aluminum. The painted aluminum chassis was obtained from a previous team at UW, and
modified using plastic k’ nex toys to adapt to the current power source and stopping mechanism.< / p >
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< / div >
< / dd >
< hr / >
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<!-- AIChE Poster -->
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< dt > Measuring Diffusion of Trichlorethylene Breakdown Products in Polyvinylalginate< / dt >
< dd >
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Thomas A. Christensen II, Samuel R. Wolfe, Jonathan Counts, Mark F. Roll, Kristopher V. Waynant, James G.
Moberly
< br / >
AIChE Annual Meeting ● Pittsburgh, PA ● October 29, 2018
< br / >
3< sup > rd< / sup > Place Environmental III Division Undergraduate Poster Competition
< br / >
< a data-toggle = "collapse" data-target = "#pva-aiche" role = "button" > Abstract < span class = "caret" > < / span > < / a >
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< a href = "https://aiche.confex.com/aiche/2018/meetingapp.cgi/Paper/545790" > < i class = "fas fa-calendar-alt" > < / i >   Conference Schedule< / a >
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< a href = "/blob/measuring_diffusion_of_trichloroethylene.pdf" > < i class = "fas fa-chart-pie" > < / i >   Full Text< / a >
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< div class = "collapse" id = "pva-aiche" >
< p class = "font-serif" > Trichloroethylene (TCE), a toxic and carcinogenic contaminant, presents unique
challenges for cleanup because of its water solubility, density, and volatility. Bioremediation of TCE
is a promising cleanup method; however, metabolism of TCE results in acid generation that inhibits
remediating microorganisms. Calcium alginate(CA)-polyvinylalcohol (PVA) hydrogels show promise for
protecting remediating microbes, however diffusion of TCE or its byproducts through these polymers is
unknown. To measure the effective diffusion coefficient of TCE and byproducts through hydrogel
membranes, we used a modified diaphragm cell. Measured effective diffusion coefficient of each species
was (cm< sup > 2< / sup > /s × < sup > 6< / sup > ): 14.0 ± 1.91 for H+ ions, 12.4 ± 1.64 for TCE, 7.83 ± 0.54 for
cis-1,2-dichloroethylene (DCE), and 4.68 ± 4.14 for vinyl chloride. These results aid in engineering
biobeads and suggest that CA-PVA hydrogel blends are effective in slowing diffusion of protons,
buffering acids produced by trichloroethylene metabolism, and remains suitable for encapsulation of
microorganisms involved in bioremediation.< / p >
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< / dd >
< hr / >
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<!-- Fast Pitch speech -->
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< dt > How to build a cow-cud fuel cell< / dt >
< dd >
Thomas A. Christensen II
< br / >
Idaho INBRE Summer Research Conference ● Moscow, ID ● August 1, 2018
< br / >
3< sup > rd< / sup > Place Fast-Pitch Science Presentation Contest
< br / >
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< a href = "https://web.archive.org/web/20190928024416/https://inbre.uidaho.edu/research/research-conference/" > < i class = "fas fa-trophy" > < / i >   Awards
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Listing< / a >
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< hr / >
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<!-- INBRE Poster -->
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< dt > Measuring diffusion of protons in polyvinylalginate< / dt >
< dd >
Thomas A. Christensen II, Jonathan Counts, James G. Moberly
< br / >
Idaho INBRE Summer Research Conference ● Moscow, ID ● July 31, 2018
< br / >
Undergraduate Poster Competition
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< a data-toggle = "collapse" data-target = "#pva-inbre" role = "button" > Abstract < span class = "caret" > < / span > < / a >
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< a
href="https://eventmobi.com/idahoinbre2018/people/c861bd6f-f4a7-4d67-a59a-199e34515776/387725dc-c893-44b6-b611-0abdf5fbcf6e">< i class = "fas fa-calendar-alt" > < / i >   Conference
Schedule< / a >
< div class = "collapse" id = "pva-inbre" >
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< p class = "font-serif" > Trichloroethylene (TCE) is a toxic and carcinogenic contaminant that presents unique
challenges for cleanup because of its density and volatility. Use of microorganisms may be a promising
remediation method, however metabolism of TCE results in acid buildup, which consequently impedes the
ability of microorganisms to perform this remediation. Polyvinylalginate (PVA) shows promise as a useful
shield for microorganisms carrying out bioremediation of TCE by surrounding them in a protective
biofilm-like layer, however, key information is missing which relates diffusion of TCE or its metabolic
products through PVA. To measure the effective diffusion coefficient of H+ ions through a PVA membrane
cross-linked with boric acid and calcium ions, we used a modified diaphragm cell. We found the effective
diffusion coefficient to be 1.40 × < sup > -5< / sup > ± 1.91 × < sup > -6< / sup > cm< sup > 2< / sup > /s, a nearly
seven-fold decrease in diffusivity compared to protons in water, with an unexpected significant but as
of yet unquantified adsorption capacity. These results suggest that polyvinylalginate is effective in
slowing diffusion of protons and buffering these acids produced by trichloroethylene metabolism, and
remains suitable for encapsulation of microorganisms involved in bioremediation.< / p >
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< / dd >
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