LOUIS University of Alabama in Huntsville
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Isolation, purification, crystallization and preliminary X-ray data analysis of the B family DNA polymerase from Thermococcus thioreducens
Get PDFFamily B DNA polymerases are the core polymerizing enzymes that carry out the essential process of DNA replication in many Archaeal organisms. Archaea depend on the unique properties of their DNA polymerases to faithfully replicate DNA within extreme environments. Variation in the catalytic properties of DNA polymerases from different organisms can be elucidated through detailed structural analysis by means of macromolecular X-ray crystallography. Crystallization is the crucial and bottleneck step in the process of determining the protein’s three-dimensional structure by X-ray diffraction—essentially no crystal, no structure. This study optimizes the isolation and purification of recombinant DNA polymerase B from Thermococcus thioreducens (TthiPolB) for crystallization. Purified TthiPolB is screened using a sparse-matrix approach by sitting droplet vapor diffusion. Crystals were obtained and finally optimized with Polyethylene glycol (PEG) as the precipitant to produce crystals suitable for X-ray diffraction. TthiPolB crystals diffracted X-ray to 4.5 Å and they were determined to have orthorhombic space group P212121 with unit cell dimensions a=70.70 Å, b= 109.56 Å, c=111.75 Å, α=β=γ=90o. X-ray data was collected to about 85% completeness and a preliminary TthiPolB structure was determined by molecular replacement revealing the molecular arrangement of the crystal lattice
Fabrication and Characterization of PDMS Based Materials for Stretchable and Flexible Electronics
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Development and Calibration of a Lightning Sensor
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Development of a high speed differential temperature sensor for in situ estimations of Cn2 in the planetary boundary layer
Get PDFThe propagation of electromagnetic energy through the Earth’s atmosphere is significantly modulated by spatial variability of the refractive index structure function (Cn2). In situ estimates of vertical profiles of Cn2 in the boundary layer are critical for evaluating model predictions and ground-based remote sensing retrievals of Cn2. This thesis describes the development of a sensor system that produces high frequency measurements of differential temperature between two points in space separated by a distance of 0.3m using two 5 diameter platinum resistance temperature sensors with 10-4K resolution. The platinum wire sensors are connected to two legs of a Wheatstone Bridge producing an analog voltage signal proportional to the temperature difference. Analog to digital conversion yields ensembles of differential temperature observations acquired at sampling rates of 200 Hz, which are averaged onboard the sensor system to compute CT2 and combined with other observations to estimate Cn2
Nonlinear dynamics of acoustic fluctuations in one-dimensional ducts with and without unsteady combustion
Get PDFThe overall objective of this research is to analyze the nonlinear dynamics of combustors in one dimensional Cartesian coordinate. This research was carried out in four parts, with each successive part building on the previous one. The first part begins with investigation of the coupled nonlinear evolution of acoustic modes in a quasi 1-D duct with axially inhomogeneous mean velocity and mean thermodynamic properties. A novel modification of the Krylov--Bogoliubov method of averaging (KBMA) is developed to analytically solve the modal-amplitude equations that are linearly and nonlinearly coupled with both quadratic and cubic nonlinearities. Approximate analytical solutions based on the method of multiple scales (MMS) are also derived for the coupled modal-amplitude equations with cubic nonlinearities. Novel initial conditions are derived for the KBMA and MMS modal amplitude and phase equations that are essential to validate the analytical solutions using numerical solutions. The second part is an advancement of first part where we derive novel solutions based on the MMS to the modal amplitude equations constitute a multi-degree-of-freedom system of linearly and nonlinearly coupled ordinary differential equations with quadratic and cubic nonlinearities. Due to the presence of both quadratic and cubic terms, the perturbation expansion for the MMS solution necessary includes terms of three orders: , and , where is the small parameter. The KBMA solutions are included in the second part to compare the MMS and KBMA approaches for the nonlinear equations with and without linear coupling. In the third part, a nonlinear coupled-oscillator model is developed that can predict the various stages of synchronization between the acoustic and heat-release oscillations in the lead-up to thermoacoustic instability in a laboratory scale dump combustor with a bluffbody-anchored flame. The coupled nonlinear equations governing the temporal evolution of pressure and heat-release-rate fluctuations are evolved along with an equation for the build-up of circulation at the dump plane, as well as an equation for vortex advection. The effects of vortex impingement on the flame are modeled as a localized, instantaneous source term in the flame oscillator equation. With the mean flow velocity as the control parameter, the nonlinear model is applied to investigate the acoustic–flame–vortex interactions. In the fourth step, we investigate the role of acoustic and combustion nonlinearities in triggering a stable cylindrical combustion chamber. Using the Galerkin method of weighted spatial integration, we derive the nonlinear equations governing the time-dependent amplitudes of the longitudinal modes of the combustion chamber. The modal amplitude equations include quadratic and cubic acoustic nonlinearities, as well as combustion nonlinearities. The latter, arising from unsteady combustion processes, are represented using three separate models that include Crocco’s pressure exponent–time lag model and two other nonlinear combustion response models
The Effectiveness of Turn Teams in Preventing Pressure Injuries
Get PDFhttps://louis.uah.edu/research-horizons/1358/thumbnail.jp
Vessels of Dynamism: Dynamic Emergence and The Questione Della Donna in Benedetta\u27s Aeropittura
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Improvements of Radial Stretch System for the Mechanical Characterization of Flexible Electronics
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Methodology, deployment, and performance of pico balloons in Antarctica
Get PDFDuring the 2022/2023 Antarctic summer, eight pico balloon flights from Neumayer Station III unveiled insights into Antarctic troposphere/stratospheric winds (9 - 15 km AMSL). The most impressive flight lasted an astounding 98 days, completing eight circumnavigations of the Southern Hemisphere. Flight data indicated zonal velocities from -50 to 250 km/hr and meridional velocities of ±100 km/hr, with total wind speeds from 2.0 to 270 km/hr. Pico balloons can ascend due to convection, altering their float density. They also drift further south than larger stratospheric balloons, reaching latitudes close to the south pole. This study showcases the transformation of budget-friendly party balloons into effective research tools, emphasizing their logistical simplicity: all materials except lifting gas were transported to Antarctica in one person’s carry-on. The work promotes pico balloons’ wider scientific application
Analyzing trust in automation using large language models
No full textThis thesis explores the measurement of trust in the context of human interactions with automated systems. Trust is influenced by factors like perceived ability, benevolence, and integrity which presents a measurement challenge. Given the lack of a universally accepted model for trust, there is an abundance of trust measurement methods in the literature. This research aimed to ascertain the reliability of NLP-based measurements to determine whether such methods can shed light on the dimensionality of trust as a construct and to isolate a Linguistic Fingerprint™ of trust. The results lent support to trust as a unidimensional construct. There was little predictive difference between congruent models (e.g., predicting trust using trust sentences) and incongruent models (e.g., predicting trust using distrust sentences). In addition to contributing to the theoretical debate as to the nature of the construct of trust, these findings have implications for the feasibility of developing real-world trust measurement tools