Genomic analysis and physiological experiments conducted on the lignocellulosic biomass degrading bacterium C. phytofermentans, indicates that it can degrade and utilize a wide-range of carbohydrates as possible growth substrates. Previous experiments characterized gene expression using custom whole genome oligonucleotide microarrays. The results indicated that C. phytofermentans utilizes ATP-binding cassette (ABC) transporters for carbohydrate uptake and does not use the sole phosphoenolpyruvate-phosphotransferase system (PTS) for any of the tested substrates.Distinct sets of Carbohydrate Active Enzymes (CAZy) genes were also up-regulated on specific substrates indicative of C. phytofermentans ability to selectively degrade lignocellulosic biomass. We also identified a highly expressed cluster of genes which includes seven extracellular glycoside hydrolases and two ABC transporters with unknown specificity on a number of substrates. These results lead to the hypothesis that when grown on plant biomass, C. phytofermentansis capable of degrading and transporting all major carbohydrate components of lignocellulose biomass. To test this, C. phytofermentans was grown on three different lignocellulosic biomass substrates (Brachypodium distachyon, cornstover, and switchgrass). Gene expression and HPLC analysis indicated that C. phytofermentans is utilizing multiple substrates with multiple sugar ABC transporter clusters, glycoside hydrolases, and sugar utilization pathways being expressed. To further test this,the sugar utilization pattern for C. phytofermentans was investigated. Growth studies were performed on individual saccaharides (glucose, cellobiose, xylose, and fucose) as well as combinations of all these sugars. From these studies we determined that C. phytofermentans does not show a characteristic diauxic shift indicative of preferential sugar utilization or carbon catabolite repression (CCR). This result was supported further by HPLC analysis indicating that co-utilization of sugars was occurring, however their were differences in the rates of consumption. Expression analysis of dual sugar combinations of glucose/cellobiose, glucose/xylose, and glucose/fucose also shows that genes involved in the transport and utilization of each sugar are expressed. We also noted glucose repression of some of the glyocside hydrolases which are normally expressed on xylose and fucose. The results from this study indicate that C. phytofermentans can utilize multiple sugars simultaneously.

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No description available.

Multichannel Analysis of Surface Waves (MASW) has become an increasingly popular geophysical method for characterizing subsurface properties. During MASW, a linear array of geophones is used to record the motion generated by Rayleigh waves (vertical motion) or Love waves (horizontal motion). The use of Rayleigh waves for MASW has been well-researched and documented. Although less work has been devoted to understanding the full potential of Love waves, previous research efforts have indicated that Love waves present several situational advantages over Rayleigh waves. Rayleigh and Love waves are dispersive, meaning the phase velocity of the waves is frequency-dependent in a vertically heterogeneous medium. Using the data collected from the generation of Rayleigh or Love waves, a dispersion image is created. Dispersion curves are extracted from this image and an inversion process converts the dispersion curve into a shear velocity (VS) profile that is used to estimate soil stiffness. This inversion process is fundamentally nonlinear and ill-posed, without a unique solution. In other words, there are more unknown than known values and multiple “correct” solutions exist. One way in which the issue of solution non-uniqueness can be mitigated is by collecting and analyzing data from both Rayleigh and Love waves. However, Rayleigh and Love waves are typically generated by different impacts on a source – vertical and horizontal strikes, respectively. Therefore, data acquisition time is significantly increased if both Rayleigh and Love wave data is collected. No studies have systematically examined the simultaneous generation of Rayleigh and Love waves for MASW using a single impact on a single source. An angled source capable of producing both Rayleigh and Love waves with a single strike could significantly improve acquisition times of Rayleigh and Love waves and encourage their joint use for MASW applications. This research effort aims to explore optimal techniques for the simultaneous generation of Rayleigh and Love waves and compare the results to traditional MASW techniques. / Civil Engineering

Media layering, the simultaneous use of multiple unrelated media sources, has been documented as an increasing behavior trend (Roberts, Foehr, & Rideout, 2005) that marks a qualitative and quantitative difference in the way media is experienced. Presently, the impact on consumers from media layering is unknown. A strong theoretical foundation of human information processing theory predicts negative consequences in terms of performance cost in learning, and degradation of attention. Related research on dual task performance and multiple-channel processing demonstrates a decline in performance. This study compared sustained attention performance on a cancellation task, the d2 Test of Attention (Brickenkamp & Zillmer, 1998), in four varying media conditions. Performance scores were evaluated to determine the effect of degrees of extraneous media saturation and media interaction on attention task performance. / Ed. D.

Low dissolved oxygen (DO) biological nutrient removal (BNR) is becoming a viable option to improve the energy efficiency of BNR. To properly model and design BNR processes for low DO operation, it is critical to fully understand how nitrifier, denitrifier, and polyphosphate accumulating organism (PAO) oxygen kinetics adapt in a shift from traditional DO operation (2 mg O2/L or more) to low DO operation. Research characterizing how oxygen kinetics shift over time in activated sludge biomass adapting to low DO is limited. Therefore, a method to characterize oxygen kinetics for nitrifiers, denitrifiers, and PAOs simultaneously is lacking. Here a method was developed to simultaneously measure the oxygen kinetics of nitrifiers, denitrifiers, and PAOs. This method, termed the SND and P-Uptake Oxygen Kinetics test, was able to estimate the ammonia oxidizing bacteria (AOB) oxygen half-saturation coefficient, ammonia maximum removal rate, denitrifier oxygen inhibition coefficient, total inorganic nitrogen (TIN) maximum removal rate, PAO oxygen half-saturation coefficient, phosphorus maximum uptake rate, and a simultaneous nitrification and denitrification (SND) optimum operation point. Three tests were conducted on the Virginia Initiative Plant (VIP) BNR Activated Sludge Pilot while it was operating at a process DO of 2 mg O2/L, and one test while it was operating at 1.5 mg O2/L. The measurements among the three initial tests showed high similarity in their parameter estimates. Estimated oxygen half-saturation and oxygen inhibition coefficients were compared to current suggested ranges and were within the expected magnitudes. At 2 mg O2/L, denitrifier oxygen inhibition coefficients and PAO oxygen half-saturation coefficients were estimated to be remarkably low here, under 0.4 and 0.1 mg O2/L, respectively. AOB oxygen half-saturation coefficients were variable here in the range of 0.62 to 2.57 mg O2/L, seeming to vary with available ammonia concentrations. Upon comparison with a previously developed respirometric test for nitrifier oxygen kinetics, termed the Declining DO test, the AOB oxygen half-saturation coefficient from the SND and P-Uptake Oxygen Kinetics test and the Declining DO test, when both were conducted on the VIP BNR Pilot, showed a similar trend. This provided validation for the AOB oxygen kinetics here and the usefulness of the test developed here. Additionally, measuring and plotting AOB and denitrifier oxygen kinetics together produced an intersection point where ammonia removal rates were equal to TIN removal rates. This intersection point was an optimum point for SND during the conditions of the test. This method can be used to characterize and track oxygen kinetic changes in a BNR system adapting from high to low DO. / Master of Science / Aerating biological processes in wastewater treatment plants is necessary to facilitate nitrogen and phosphorus removal but is extremely costly. Traditional dissolved oxygen concentrations in these processes are 2 mg O2/L or higher. Operating processes with low dissolved oxygen (DO) concentrations, less than 1 mg O2/L, can cut costs significantly. However, designing processes at low DO concentrations requires knowledge of how microorganisms utilize substrate with lower oxygen availability and how substrate utilization develops when gradually decreasing the DO concentration in a process. Here, a method was developed to measure the parameters describing the relationship between substrate utilization and DO concentration for the microorganisms responsible for nitrogen removal (nitrifiers and denitrifiers) and phosphorous removal (polyphosphate accumulating organisms). Additionally, the method provides an optimum DO setpoint for simultaneous nitrification and denitrification (SND) during testing conditions. This method, termed the SND and P-Uptake Oxygen Kinetics test, was able to estimate the following parameters simultaneously: ammonia oxidizing bacteria (AOB) oxygen half-saturation coefficient, ammonia maximum removal rate, denitrifier oxygen inhibition coefficient, total inorganic nitrogen (TIN) maximum removal rate, PAO oxygen half-saturation coefficient, and phosphorus maximum removal rate. Three tests were conducted on the Virginia Initiative Plant (VIP) BNR Activated Sludge Pilot while it was operating at a process DO of 2 mg O2/L, and one test while it was operating at 1.5 mg O2/L. The measurements among the three initial tests showed high similarity in their parameter estimates. Estimated oxygen half-saturation and oxygen inhibitions coefficients were compared to current suggested ranges and were within the expected magnitudes. Upon comparison with a previously developed test for nitrifier oxygen kinetics, termed the Declining DO test, the AOB oxygen half-saturation coefficient from the SND and P-Uptake Oxygen Kinetics test and the Declining DO test when both were conducted on the VIP BNR Pilot showed a similar trend, providing validation for the usefulness of the test developed here.

This dissertation represented an initial effort to model spousal family purchase decision behavior in terms of spousal coercion propensity. Two major issues concerning how spouses resolve conflicts were investigated: (1) What are the spousal behavioral interactions in household conflict resolution processes? (2) What are the temporal aspects of spousal family decision behaviors? It was hypothesized that spouses tend to not reciprocate their partners' uses of coercive influence strategies in a decision, given their avoidance of conflict. Also, spouses who used more power in the past tend to use less power in order to maintain equity in the long-term marital relationship. It was also hypothesized that spousal coercion propensity are contingent upon marital power, love, and preference intensity. Marital power and preference intensity are positively related to spousal coercion propensity while love predicts weaker coercive decision behavior. Consistently, it was proposed that coercive influence strategies are more effective in the short run, given the spouses' conflict avoidance and sense of equity in marriage. Thus, spouses who used coercive strategies are more satisfied with the decision outcome but less satisfied with the decision process. A dynamic simultaneous equations model (DSE) was developed to test the major hypotheses of this dissertation. The model was calibrated by means of an Autoregressive Two-Stage Least Square (A2SLS) approach. MANOVAs and a set of binary logistic regressions and linear multiple regressions were used to test the other hypotheses. The empirical study involving a random sample provided adequate support for the model. The implications of the findings, theoretical and managerial alike, limitations of the study, and future research directions were discussed. / Ph. D.

Java applets are developed to assist in the learning of basic structural analysis concepts. In order for these programs to be easily available over the Internet, they are written in the object-oriented Java programming language. The Java programs known as applets are embedded in HTML documents. The HTML documents, part of a series of instructional units, present the topics demonstrated by the applets. The applets include truss and frame determinacy applets; a three-hinged arch bridge applet; determinate and indeterminate truss analysis applets; determinate and indeterminate frame analysis applets and an influence line analysis applet. These programs are available to any student or instructor with Internet access. The applets provide good examples of the application of object-oriented programming and the development of software for a graphical user interface. They also serve as excellent tools that facilitate the understanding of structural engineering concepts utilizing a medium that allows independent learning at an individual pace. / Master of Science

Successful future surface combatants in the US Navy must embrace the growing integration and interdependency of propulsive and combat systems. Traditionally, the development of Hull, Mechanical and Electrical systems has been segregated from the development of weapons and sensors. However, with the incorporation of high energy weapons into future ship configurations, ship design processes must evolve to embrace the concept of a System of Systems being the only way to achieve affordable capability in our future fleets. This thesis bridges the gap between the physical architecture of components within a ship and the way in which they are logically connected to model the energy flow through a representative design and provide insight into sizing requirements of both system components and their connections using an Architecture Flow Optimization (AFO). This thesis presents a unique method and tool to optimize naval ship system logical and physical architecture considering necessary operational conditions and possible damage scenarios. The particular and unique contributions of this thesis are: 1) initially only energy flow is considered without explicit consideration of commodity flow (electric, mechanical, chilled water, etc.), which is calculated in post-processing; 2) AFO is applied to a large and complex naval surface combatant system of systems, demonstrating its scalability; 3) data necessary for the AFO is extracted directly from a naval ship synthesis model at a concept exploration level of detail demonstrating its value in early stage design; and 4) it uses network-based methods which make it adaptable to future knowledge-based network analysis methods and approaches. / Master of Science / The US Navy faces a future where their ships will be required to perform a greater number and increasingly more diverse mission set while the resources provided to them dwindle. Traditionally, propulsive, electrical and weapons systems onboard ships have been segregated in their development, however, with the incorporation of high energy weapons into future ship configurations, the ship design processes must evolve to incorporate these interdependent power consumers. To take advantage of emerging technologies in a resource constrained environment, the future fleet of the US Navy must incorporate the concept of a “System of Systems” early in the ship design process. This thesis correlates the energy available onboard a ship to how it can be distributed to components in the execution of required missions. Additionally, this thesis provides insight into the sizing requirements of intermediary and auxiliary components using an Architecture Flow Optimization (AFO) by only analyzing energy flow without considering the commodity flow (electricity, mechanical power, chilled water, etc.) which can be calculated post optimization. Using network-based methods allows the AFO to be adaptable to future knowledge-based network analysis methods and approaches while using data directly from a naval ship synthesis model enables the AFO to be scaled to incorporate a large and complex system of systems proving its value to early stage design.

The purpose of this thesis is to examine multi-core technology. Multi-core architecture provides benefits such as less power consumption, scalability, and improved application performance enabled by thread-level parallelism.