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- Creators: Arizona State University
Description
De facto potable reuse (DFR) occurs when surface water sources at drinking water treatment plants (DWTPs) contain treated effluents from upstream wastewater treatment plants (WWTPs). Contaminants of emerging concerns (CECs) originate from treated effluents (e.g., unregulated disinfection by-products, pathogenic microorganisms as Cryptosporidium oocyst, Giardia cyst, and Norovirus) can be present in surface water and pose human health risks linked to CECs. Previously developed De facto Reuse Incidence in our Nations Consumable Supply (DRINCS) model predicted DFR for the national largest DWTPs that serve >10,000 people (N = 2,056 SW intakes at 1,210 DWTPs). The dissertation aims to quantify DFR at all surface water intakes for smaller DWTPs serving ≤10,000 people across the United States and develop a programmed ArcGIS tool for proximity analysis between upstream WWTPs and DWTPs. The tested hypothesis is whether DWTPs serving ≤10,000 people are more likely to be impacted by DFR than larger systems serving > 10,000 people.The original DRINCS model was expanded to include all smaller DWTPs (N = 6,045 SW intakes at 3,984 DWTPs) in the U.S. First, results for Texas predicted that two-thirds of all SW intakes were impacted by at least one WWTP upstream. The level of DFR at SW intakes in Texas ranged between 1% to 20% under average flow and exceeded 90% during mild droughts. Smaller DWTPs in Texas had a higher frequency of DFR than larger systems while < 10% of these DWTPs employed advanced technology (AT) capable of removing CECs. Second, nationally over 40% of surface water intakes at all DWTPs were impacted by DFR under average flow (2,917 of 6,826). Smaller DWTPs had a higher frequency (1,504 and 1,413, respectively) of being impacted by upstream WWTP discharges than larger DWTPs. Third, the difference in DFR levels at smaller versus larger DWTPs was statistically unclear (t-test, p = 0.274). Smaller communities could have high risks to CECs as they rely on surface water from lower-order streams impacted by DFR. Furthermore, smaller DWTPs lack more than twice as advanced unit processes as larger DWTPs with 52.1% and 23%, respectively. DFR levels for DWTPs serving > 10,000 people were statistically higher on mid-size order streams (3, 5, and 8) than those for smaller DWTPs. Finally, DWTPs serving > 10,000 people could pose risks to a population impacted by DFR > 1% as 40 times as those served by smaller DWTPs with 71 million and 1.7 million people, respectively. The total exposed population to risks of CECs served by DWTPs impacted by upstream WWTP discharges (DFR >10%) was estimated at 12.3 million people in the United States. Future studies can use DRINCS results to conduct an epidemiological risk assessment for impacted communities and identify communities that would benefit from advanced technology to remove CECs.
ContributorsNguyen, Thuy Thi Thu (Author) / Westerhoff, Paul K (Thesis advisor) / Hristovski, Kiril (Committee member) / Fox, Peter (Committee member) / Muenich, Rebecca (Committee member) / Quay, Ray (Committee member) / Arizona State University (Publisher)
Created2020
Description
The quest to find efficient algorithms to numerically solve differential equations isubiquitous in all branches of computational science. A natural approach to address
this problem is to try all possible algorithms to solve the differential equation and
choose the one that is satisfactory to one's needs. However, the vast variety of algorithms
in place makes this an extremely time consuming task. Additionally, even
after choosing the algorithm to be used, the style of programming is not guaranteed
to result in the most efficient algorithm. This thesis attempts to address the same
problem but pertinent to the field of computational nanoelectronics, by using PETSc
linear solver and SLEPc eigenvalue solver packages to efficiently solve Schrödinger
and Poisson equations self-consistently.
In this work, quasi 1D nanowire fabricated in the GaN material system is considered
as a prototypical example. Special attention is placed on the proper description
of the heterostructure device, the polarization charges and accurate treatment of the
free surfaces. Simulation results are presented for the conduction band profiles, the
electron density and the energy eigenvalues/eigenvectors of the occupied sub-bands
for this quasi 1D nanowire. The simulation results suggest that the solver is very
efficient and can be successfully used for the analysis of any device with two dimensional
confinement. The tool is ported on www.nanoHUB.org and as such is freely
available.
this problem is to try all possible algorithms to solve the differential equation and
choose the one that is satisfactory to one's needs. However, the vast variety of algorithms
in place makes this an extremely time consuming task. Additionally, even
after choosing the algorithm to be used, the style of programming is not guaranteed
to result in the most efficient algorithm. This thesis attempts to address the same
problem but pertinent to the field of computational nanoelectronics, by using PETSc
linear solver and SLEPc eigenvalue solver packages to efficiently solve Schrödinger
and Poisson equations self-consistently.
In this work, quasi 1D nanowire fabricated in the GaN material system is considered
as a prototypical example. Special attention is placed on the proper description
of the heterostructure device, the polarization charges and accurate treatment of the
free surfaces. Simulation results are presented for the conduction band profiles, the
electron density and the energy eigenvalues/eigenvectors of the occupied sub-bands
for this quasi 1D nanowire. The simulation results suggest that the solver is very
efficient and can be successfully used for the analysis of any device with two dimensional
confinement. The tool is ported on www.nanoHUB.org and as such is freely
available.
ContributorsBaikadi, Pranay Kumar Reddy (Author) / Vasileska, Dragica (Thesis advisor) / Goodnick, Stephen (Committee member) / Povolotskyi, Mykhailo (Committee member) / Arizona State University (Publisher)
Created2020
Description
The need of organs for transplantation has become an increasing medical need due to a limited donor organ supply. Many organs fail within 10 years due to acute and chronic rejection. Acute or antibody mediated rejection leads to decreased long term graft survival and increases the need for a repeat transplant. In prior work, reducing endothelial heparan sulfation and blockade of chemokine-glycosaminoglycan (GAG) interaction with Myxomavirus-derived protein, M-T7, reduced aortic and renal graft vascular inflammation and rejection. Conditional endothelial Ndst1 deficiency and inhibition of chemokine-GAG interaction reduces early allograft damage and suggest new therapeutic options for graft rejection. Here acute renal rejection was examined in grafts with conditional endothelial N-deacetylase-N-sulfotransferase-1 knockout (Ndst1-/-) and in wildtype (WT) C57Bl6/J grafts treated with saline, M-T7, antisense oligonucleotides (ASO) for Ndst1 or a scrambled ASO control. Viruses have a highly adaptive ability to evade hosts defense and immune response. The immunomodulatory proteins derived from viruses provide potential therapeutic uses to alleviate this need for organs. The Myxoma virus derived protein M-T7 is a promising therapeutic for reducing kidney transplant rejection. Orthotopic transplantations in mice are extremely difficult and costly because they require a highly trained microsurgeon. This kidney to kidney subcapsular and subcutaneous transplant model is a practical and simpler method that requires fewer mice, one kidney can be used for transplants in 6 or more mice and there is much lower morbidity, pain and mortality. Heterotopic transplantation of allografts is a simple model for preliminary testing of treatments for early inflammation, ischemia, and graft rejection. Subcapsular kidney transplantation provides a first step approach to test virus-derived proteins as potential treatments to reduce transplant rejection and inflammation. This project reports on a broadly applicable platform on which to rapidly and conveniently test new treatments for transplant rejection. This finding will significantly lower the barrier to entry for labs which are interested in translating their laboratory findings to animal models of organ transplantation which is a complex surgical procedure, and thus accelerate the bench-to-bedside translation of novel, putative treatments for transplant rejection as an initial screening tool.
ContributorsBurgin, Michelle A (Author) / McFadden, Douglas (Thesis advisor) / Lucas, Alexandra R (Thesis advisor) / Yaron, Jordan R (Committee member) / Lim, Efrem S. (Committee member) / Hogue, Brenda G (Committee member) / Arizona State University (Publisher)
Created2020
Description
The purpose of this document is to identify contemporary issues facing female-identifying professional trombonists today. Interviews were conducted with three prominent women in the international trombone community, including questions that sought to foster discussion on the extent to which their experience as professional trombonists was influenced by their gender. The topic of microaggressions emerged as significant, as it became clear throughout the interview process that these women experience microaggressions far more commonly than overt gender discrimination, as did the topic of coping mechanisms. The interview questions also sparked discussions of identity, self-motivation, and local cultural norms within the context of each woman’s musical career.
ContributorsBroome-Robinson, Julia (Author) / Edwards, Bradley (Thesis advisor) / Swoboda, Deanna (Committee member) / Wells, Christopher (Committee member) / Arizona State University (Publisher)
Created2020
Description
This research focuses mainly on employing tunable materials to achieve dynamic radiative properties for spacecraft and building thermal management. A secondary objective is to investigate tunable materials for optical propulsion applications. The primary material investigated is vanadium dioxide (VO2), which is a thermochromic material with an insulator-to-metal phase transition. VO2 typically undergoes a dramatic shift in optical properties at T = 341 K, which can be reduced through a variety of techniques to a temperature more suitable for thermal control applications. A VO2-based Fabry-Perot variable emitter is designed, fabricated, characterized, and experimentally demonstrated. The designed emitter has high emissivity when the radiating surface temperature is above 345 K and low emissivity when the temperature is less than 341 K. A uniaxial transfer matrix method and Bruggeman effective medium theory are both introduced to model the anisotropic properties of the VO2 to facilitate the design of multilayer VO2-based devices. A new furnace oxidation process is developed for fabricating high quality VO2 and the resulting thin films undergo comprehensive material and optical characterizations. The corresponding measurement platform is developed to measure the temperature-dependent transmittance and reflectance of the fabricated Fabry-Perot samples. The variable heat rejection of the fabricated samples is demonstrated via bell jar and cryothermal vacuum calorimetry measurements. Thermal modeling of a spacecraft equipped with variable emittance radiators is also conducted to elucidate the requirements and the impact for thermochromic variable emittance technology.
The potential of VO2 to be used as an optical force modulating device is also investigated for spacecraft micropropulsion. The preliminary design considers a Fabry-Perot cavity with an anti-reflection coating which switches between an absorptive “off” state (for insulating VO2) and a reflective “on” state (for metallic VO2), thereby modulating the incident solar radiation pressure. The visible and near-infrared optical properties of the fabricated vanadium dioxide are examined to determine if there is a sufficient optical property shift in those regimes for a tunable device.
The potential of VO2 to be used as an optical force modulating device is also investigated for spacecraft micropropulsion. The preliminary design considers a Fabry-Perot cavity with an anti-reflection coating which switches between an absorptive “off” state (for insulating VO2) and a reflective “on” state (for metallic VO2), thereby modulating the incident solar radiation pressure. The visible and near-infrared optical properties of the fabricated vanadium dioxide are examined to determine if there is a sufficient optical property shift in those regimes for a tunable device.
ContributorsTaylor, Sydney June (Author) / Wang, Liping (Thesis advisor) / Wells, Valana (Committee member) / Yu, Hongbin (Committee member) / Wang, Robert (Committee member) / Thangavelautham, Jekanthan (Committee member) / Massina, Christopher J (Committee member) / Arizona State University (Publisher)
Created2020
Description
Power management circuits have been more and more widely used in various applications, while providing fully integrated voltage regulation remains a challenging topic. Switched-capacitor (SC) voltage converters have received attentions in integrated power conversion for fixed-ratio voltage conversions with good efficiency and feasibility of integration. During my PhD study, an on-chip current sensing technique is proposed to dynamically modulate both switching frequency and switch widths of SC voltage converters, enhancing fast transient response and higher efficiency across a wide range of load currents. In conjunction with SC converters, a low-dropout regulator (LDO) is implemented which is driven by a push-pull operational transconductance amplifier (OTA), whose current is mirrored and sensed with minimal power and efficiency overhead. The sensed load current directly controls the frequency and width of SC converters through a voltage-controlled oscillator (VCO) and a time-to-digital converter, respectively.
Theoretical analysis and optimization for SC DC-DC converters have been presented in prior works, however optimization of different capacitors, namely flying and input/output decoupling capacitors, in SC voltage regulators (SCVRs) under an area constraint has not been addressed. A methodology to optimize flying and decoupling capacitance for area-constrained on-chip SCVRs to achieve the highest system-level power efficiency. Considering both conversion efficiency and droop voltage against fast load transients, the proposed model determines the optimal ratio between flying and decoupling.
Based on the previous design, a fully integrated switched-capacitor voltage regulator with voltage comparison and on-chip lossless current sensing control is proposed. Based on the voltage comparison result and sensed current as the load current changes, the frequency of the SC converters are modulated for optimal efficiency. The voltage regulator targets 2.1V input voltage and 0.9V output voltage, which offers higher-voltage power transfer across chip package. A 17-phase interleaved structure is used to reduce output voltage ripple.
In 65nm CMOS, the regulator is implemented with MIM-capacitor, targeting 2.1V input voltage and 0.9V output voltage. According to the measurement results, the proposed SC voltage regulator achieves 69.6% peak efficiency at 60mA load current, which corresponds to a 4.2mW/mm2 power-area density and 12.5mW
F power-capacitance density. The efficiency across 20mA to 92mA regulator load current range is above 62%. The steady-state output voltage ripple across 22x load current range of 3.5mA-76mA is between 50mV to 60mV.
Theoretical analysis and optimization for SC DC-DC converters have been presented in prior works, however optimization of different capacitors, namely flying and input/output decoupling capacitors, in SC voltage regulators (SCVRs) under an area constraint has not been addressed. A methodology to optimize flying and decoupling capacitance for area-constrained on-chip SCVRs to achieve the highest system-level power efficiency. Considering both conversion efficiency and droop voltage against fast load transients, the proposed model determines the optimal ratio between flying and decoupling.
Based on the previous design, a fully integrated switched-capacitor voltage regulator with voltage comparison and on-chip lossless current sensing control is proposed. Based on the voltage comparison result and sensed current as the load current changes, the frequency of the SC converters are modulated for optimal efficiency. The voltage regulator targets 2.1V input voltage and 0.9V output voltage, which offers higher-voltage power transfer across chip package. A 17-phase interleaved structure is used to reduce output voltage ripple.
In 65nm CMOS, the regulator is implemented with MIM-capacitor, targeting 2.1V input voltage and 0.9V output voltage. According to the measurement results, the proposed SC voltage regulator achieves 69.6% peak efficiency at 60mA load current, which corresponds to a 4.2mW/mm2 power-area density and 12.5mW
F power-capacitance density. The efficiency across 20mA to 92mA regulator load current range is above 62%. The steady-state output voltage ripple across 22x load current range of 3.5mA-76mA is between 50mV to 60mV.
ContributorsMi, Xiaoyang (Author) / Seo, Jae-Sun (Thesis advisor) / Bakkaloglu, Bertan (Committee member) / Ogras, Umit Y. (Committee member) / Kitchen, Jennifer (Committee member) / Arizona State University (Publisher)
Created2020
Description
Communications between air traffic controllers and pilots are critical to national airspace traffic management. Measuring communications in real time made by pilots and air traffic controllers has the potential to predict human error. In this thesis a measure for Deviations from Closed Loop Communications is defined and tested to predict a human error event, Loss of Separation (LOS). Six retired air traffic controllers were recruited and tested in three conditions of varying workload in an Terminal Radar Approach Control Facility (TRACON) arrival radar simulation. Communication transcripts from simulated trials were transcribed and coding schemes for Closed Loop Communication Deviations (CLCD) were applied. Results of the study demonstrated a positive correlation between CLCD and LOS, indicating that CLCD could be a variable used to predict LOS. However, more research is required to determine if CLCD can be used to predict LOS independent of other predictor variables, and if CLCD can be used in a model that considers many different predictor variables to predict LOS.
ContributorsLieber, Christopher Shane (Author) / Cooke, Nancy J. (Thesis advisor) / Gutzwiller, Robert S (Committee member) / Niemczyk, Mary (Committee member) / Arizona State University (Publisher)
Created2020
Description
Elucidation of Antigen-Antibody (Ag-Ab) interactions is critical to the understanding of humoral immune responses to pathogenic infection. B cells are crucial components of the immune system that generate highly specific antibodies, such as IgG, towards epitopes on antigens. Serum IgG molecules carry specific molecular recognition information concerning the antigens that initiated their production. If one could read it, this information can be used to predict B cell epitopes on target antigens in order to design effective epitope driven vaccines, therapies and serological assays. Immunosignature technology captures the specific information content of serum IgG from infected and uninfected individuals on high density microarrays containing ~105 nearly random peptide sequences. Although the sequences of the peptides are chosen to evenly cover amino acid sequence space, the pattern of serum IgG binding to the array contains a consistent signature associated with each specific disease (e.g., Valley fever, influenza) among many individuals. Here, the disease specific but agnostic behavior of the technology has been explored by profiling molecular recognition information for five pathogens causing life threatening infectious diseases (e.g. DENV, WNV, HCV, HBV, and T.cruzi). This was done by models developed using a machine learning algorithm to model the sequence dependence of the humoral immune responses as measured by the peptide arrays. It was shown that the disease specific binding information could be accurately related to the peptide sequences used on the array by the machine learning (ML) models. Importantly, it was demonstrated that the ML models could identify or predict known linear epitopes on antigens of the four viruses. Moreover, the models identified potential novel linear epitopes on antigens of the four viruses (each has 4-10 proteins in the proteome) and of T.cruzi (a eukaryotic parasite which has over 12,000 proteins in its proteome). Finally, the predicted epitopes were tested in serum IgG binding assays such as ELISAs. Unfortunately, the assay results were inconsistent due to problems with peptide/surface interactions. In a separate study for the development of antibody recruiting molecules (ARMs) to combat microbial infections, 10 peptides from the high density peptide arrays were tested in IgG binding assays using sera of healthy individuals to find a set of antibody binding termini (ABT, a ligand that binds to a variable region of the IgG). It was concluded that one peptide (peptide 7) may be used as a potential ABT. Overall, these findings demonstrate the applications of the immunosignature technology ranging from developing tools to predict linear epitopes on pathogens of small to large proteomes to the identification of an ABT for ARMs.
ContributorsCHOWDHURY, ROBAYET (Author) / Woodbury, Neal (Thesis advisor) / LaBaer, Joshua (Committee member) / Sulc, Petr (Committee member) / Arizona State University (Publisher)
Created2020
Description
Lattice-based Cryptography is an up and coming field of cryptography that utilizes the difficulty of lattice problems to design lattice-based cryptosystems that are resistant to quantum attacks and applicable to Fully Homomorphic Encryption schemes (FHE). In this thesis, the parallelization of the Residue Number System (RNS) and algorithmic efficiency of the Number Theoretic Transform (NTT) are combined to tackle the most significant bottleneck of polynomial ring multiplication with the hardware design of an optimized RNS-based NTT polynomial multiplier. The design utilizes Negative Wrapped Convolution, the NTT, RNS Montgomery reduction with Bajard and Shenoy extensions, and optimized modular 32-bit channel arithmetic for nine RNS channels to accomplish an RNS polynomial multiplication. In addition to a full software implementation of the whole system, a pipelined and optimized RNS-based NTT unit with 4 RNS butterflies is implemented on the Xilinx Artix-7 FPGA(xc7a200tlffg1156-2L) for size and delay estimates. The hardware implementation achieves an operating frequency of 47.043 MHz and utilizes 13239 LUT's, 4010 FF's, and 330 DSP blocks, allowing for multiple simultaneously operating NTT units depending on FGPA size constraints.
ContributorsBrist, Logan Alan (Author) / Chakrabarti, Chaitali (Thesis advisor) / Papandreou-Suppappola, Antonia (Committee member) / Bliss, Daniel (Committee member) / Arizona State University (Publisher)
Created2020
Description
The continued reliance on fossil fuel for energy resources has proven to be unsustainable, leading to depletion of world reserves and emission of greenhouse gases during their combustion. Therefore, research initiatives to develop potentially carbon-neutral biofuels were given the highest importance. Hydrothermal liquefaction (HTL, a thermochemical conversion process) of microalgae is recognized as a favorable and efficient technique to produce liquid biofuels from wet feedstocks. In this work, three different microalgae (Kirchneriella sp., Galdieria sulphuraria, Micractinium sp.) grown and harvested at Arizona State University were hydrothermally liquefied to optimize their process conditions under different temperatures (200-375 °C), residence times (15-60 min), solids loadings (10-20 wt.%), and process pressures (9-24 MPa). A one-factor-at-a-time approach was employed, and comprehensive experiments were conducted at 10 % solid loadings and a residence time of 30 min. Co-liquefaction of Salicornia bigelovii Torr. (SL), Swine manure (SM) with Cyanidioschyzon merolae (CM) was tested for the presence of synergy. A positive synergistic effect was observed during the co-liquefaction of biomasses, where the experimental yield (32.95 wt.%) of biocrude oil was higher than the expected value (29.23 wt.% ). Co-liquefaction also led to an increase in the energy content of the co-liquefied biocrude oil and a higher energy recovery rate ( 88.55 %). The HTL biocrude was measured for energy content, elemental, and chemical composition using GC-MS. HTL aqueous phase was analyzed for potential co-products by spectrophotometric techniques and is rich in soluble carbohydrates, dissolved ammoniacal nitrogen, and phosphates. HTL biochar was studied for its nutrient content (nitrogen and phosphorous) and viability of its recovery to cultivate algae without any inhibition using the nutrient leaching. HTL biochar was also studied to produce hydrogen via pyrolysis using a membrane reactor at 500 °C, 1 atm, for 24 h to produce 5.93 wt.% gas. The gaseous product contains 45.7 mol % H2, 44.05 ml % CH4, and 10.25 mol % of CO. The versatile applications of HTL biochar were proposed from a detailed physicochemical characterization. The metal impurities in the algae, bio-oil, and biochar were quantified by ICP-OES where algae and biochar contain a large proportion of phosphorous and magnesium.
ContributorsDandamudi, Kodanda Phani Raj (Author) / Deng, Shuguang (Thesis advisor) / Lammers, Peter J. (Committee member) / Fini, Elham H. (Committee member) / Lind Thomas, MaryLaura (Committee member) / Varman, Arul M. (Committee member) / Arizona State University (Publisher)
Created2020