A Computational Analysis Of The Aerodynamic And Aeromechanical Behavior Of The Purdue Multistage Compressor

Compressor design programs are becoming more reliant on computational tools to predict and optimize aerodynamic and aeromechanical behavior within a compressor. Recent trends in compressor development continue to push for more efficient, lighter weight, and higher performance machines. To meet these demands, designers must better understand the complex nature of the inherently unsteady flow physics inside of a compressor. As physical testing can be costly and time prohibitive, CFD and other computational tools have become the workhorse during design programs. The objectives of this research were to investigate the aerodynamic and aeromechanical behavior of the Purdue multistage compressor, as well as analyze novel concepts for reducing rotor resonant responses in compressors. Advanced computational tools were utilized to allow an in-depth analysis of the flow physics and structural characteristics of the Purdue compressor, and complement to existing experimental datasets. To analyze the aerodynamic behavior of the compressor a Rolls-Royce CFD code, developed specifically for multistage turbomachinery flows, was utilized. Steady-state computations were performed using the RANS solver on a single-passage mesh. Facility specific boundary conditions were applied to the model, increasing the model fidelity and overall accuracy of the predictions. Detailed investigations into the overall compressor performance, stage performance, and individual blade row performance were completed. Additionally, separation patterns on stator vanes at different loading conditions were investigated by plotting pathlines near the stator suction surfaces. Stator cavity leakage flows were determined to influence the size and extent of stator hub separations. In addition to the aerodynamic analysis, a Rolls-Royce aeroelastic CFD solver was utilized to predict the forced response behavior of Rotor 2, operating at the 1T mode crossing of the Campbell Diagram. This computational tool couples aerodynamic predictions with structural models to determine maximum Rotor 2 vibration amplitudes excited by both vortical and potential disturbances. A multi-bladerow, full-annulus unsteady simulation was performed to capture the aerodynamic forcing functions and understand the influence of bladerow interactions on these flow disturbances. The strength and frequency content of the S1 vortical field and S2 potential field were examined to quantify the aerodynamic forces exciting resonant vibrations. Detailed comparisons were made to experimental datasets acquired on the Purdue compressor which characterize the forced response behavior at the 1T mode crossing. Lastly, stator asymmetry was examined as a means of reducing forced response vibration amplitudes. For this study, a new Stator 1 ring was designed with a reduced vane count, creating the ability to isolate the relative contribution of the S1 wakes on R2 vibrational amplitudes. A second Stator 1 ring was then designed with asymmetric vane spacing such that two stator half-sectors of different vane counts were joined together to form a full stator ring. By joining two stator half-sectors with different vane counts, the energy of the wakes is spread into additional frequencies, thereby reducing the overall amplitudes. The aeroelastic CFD solver was again used to perform steady-state and unsteady simulations, capturing the effect of the stator asymmetry on resonant vibrational amplitudes. The resulting blade deflection amplitudes are presented and discussed in detail

Research and development for the data, trigger and control card in preparation for Hi-Lumi lhc

When the Large Hadron Collider (LHC) increases its luminosity by an order of magnitude in the coming decade, the experiments that sit upon it must also be upgraded to continue to their physics performance in the increasingly demanding environment. To achieve this, the Compact Muon Solenoid (CMS) experiment will make use of tracking information in the Level-1 trigger for the first time, meaning that track reconstruction must be achieved in less than 4 μs in an all-FPGA architecture. MUonE is an experiment aiming to make an accurate measurement of the the hadronic contribution to the anomalous magnetic moment of the muon. It will achieve this by making use of similar apparatus to that designed for CMS and benefit from the research and development efforts there. This thesis presents both development and testing work for the readout chain from tracker module to back-end processing card, as well as the results and analysis of a beam test used to validate this chain for both CMS and the MUonE experiment.Open Acces

The dominant discourse of central bank independence

The period from 1960 to 2000 saw a major evolution in monetary policy and institutions. This dissertation makes the claim that there is a better explanation of these events than the typical narrative, or dominant discourse. The typical narrative is that a relationship between inflation and unemployment (the Phillips Curve) was proposed around 1960. One interpretation of the relationship was that increasing aggregate demand would reduce unemployment with some acceptable inflation. Milton Friedman then stated in 1968 that, in the long run, this practice would entrench inflationary expectations and there would be no useful employment benefits. This was accepted by the economics profession, especially by the mid-1970s, around the time of the first oil shock. This period also saw the rise of stagflation and the countries that managed the inflationary outbreak best were those where independent central banks were able to withstand politicians’ short term instincts. Economists attributed this to a commitment concept; if governments could override their central bank only at the cost of legislation or constitutional change, then monetary policy would focus more on long term expectations, rather than the political short term. Empirical work in the 1990s established this relationship and many countries made their central banks more independent during this decade. A better view acknowledges some features of this narrative. For example, Milton Friedman’s theory of expectations was very influential. (Chapter 2). But there is reduced evidence for the rest of this narrative. For example, the Federal Reserve did tighten monetary policy after 1982 compared with the period before 1979, but this appears to have been through placing less emphasis on output instead of being more inflation averse. Further, policymakers in the late 1960s and 1970s underestimated the level of unemployment at which inflation started increasing. (Chapter 3). Politicians were generally involved in disinflations, but their role and visibility decreased as legal inflation and central bank independence (CBI) increased. This suggests that, in practice, legal independence bestows the disinflation role on the central bank (Chapter 4). The role of politicians, however, is not fully clear because the proportion of elections where a voter backlash against inflation occurred was small. Therefore, the political dynamic against inflation may have occurred through elites, rather than popular opinion (Chapter 5). Finally, there was not a strong correlation between CBI in developed countries because the literature made errors of omitted variable bias and not examining whether CBI was endogenous. Inflation in the 1970s and 1980s was more clearly related to economic factors such as currency performance, output, past inflation, oil prices, and a time trend (Chapter 6). The weakness of CBI theory is that, by excluding politics, it overstates the costs of overriding a central bank. If there is little popular support for disinflation, then the costs of overriding the central bank will be low, regardless of the legal arrangements in place. Central banks perceive this and deliver policy within the politically palatable decision set

Compilation of an anthology of concert band scores for study by conducting students.

The purpose of this project is to give a detailed description of the process involved in developing an anthology of excerpts from musical scores. The scope of the final project will encompass works for concert band and is intended for use as a study guide for advanced undergraduate and graduate conducting students. This. paper details the methods used for selecting compositions to be considered for inclusion, the final selection process for inclusion, relevant observations made during these processes, and the format of the completed anthology. The selection process took place in two parts. The first part involved soliciting suggestions for inclusion from a small group of nationally known college and university band directors, analyzing their responses, and constructing a survey to be given to a larger group of college and university music educators and band directors. The next phase of the project involved selecting the survey group, analyzing their responses, and compiling the list of compositions to be used in the final project. The final analysis of the results from the second survey showed a consensus of opinion with regard to compositions that should be included in this type of work

Three months journeying of a Hawaiian monk seal

Hawaiian monk seals (Monachus schauinslandi) are endemic to the Hawaiian Islands and are the most endangered species of marine mammal that lives entirely within the jurisdiction of the United States. The species numbers around 1300 and has been declining owing, among other things, to poor juvenile survival which is evidently related to poor foraging success. Consequently, data have been collected recently on the foraging habitats, movements, and behaviors of monk seals throughout the Northwestern and main Hawaiian Islands. Our work here is directed to exploring a data set located in a relatively shallow offshore submerged bank (Penguin Bank) in our search of a model for a seal's journey. The work ends by fitting a stochastic differential equation (SDE) that mimics some aspects of the behavior of seals by working with location data collected for one seal. The SDE is found by developing a time varying potential function with two points of attraction. The times of location are irregularly spaced and not close together geographically, leading to some difficulties of interpretation. Synthetic plots generated using the model are employed to assess its reasonableness spatially and temporally. One aspect is that the animal stays mainly southwest of Molokai. The work led to the estimation of the lengths and locations of the seal's foraging trips.Comment: Published in at http://dx.doi.org/10.1214/193940307000000473 the IMS Collections (http://www.imstat.org/publications/imscollections.htm) by the Institute of Mathematical Statistics (http://www.imstat.org

ThinkPiece: Embracing Love as an Educational Force in the Anthropocene

In the past decade, an increasing number of geologists and other scientific researchers have presented evidence that we have entered a new geologic epoch called the Anthropocene. The primary characteristic of the Anthropocene, researchers argue, revolves around the combination of an emerging and measurable sedimentary layer of increasing human artifacts (mostly plastics) in combination with significant and negative transformations within the Earth’s biodiversity and climate systems. In this article, the researchers were interested in exploring how anthropogenic events will likely affect educational systems and institutions through multi-decade environmental audits and educational planning that are more closely linked to addressing the world’s major anthropogenic problems such as climate change and a global loss of biodiversity related to human development and activity. This article concludes by exploring how anthropogenic forces might be redirected as human catalysts for a more positive environmental and geologic legacy. Keywords: Anthropocene, anthropogenic force, environmental education, educational catalysts, emotio

Beta particle energy spectra shift due to self-attenuation effects in environmental sources

In order to predict and control the environmental and health impacts of ionising radiation in environmental sources such as groundwater, it is necessary to identify the radionuclides present. Beta-emitting radionuclides are frequently identified by measuring their characteristic energy spectra. The present work shows that self-attenuation effects from volume sources result in a geometry-dependent shift in the characteristic spectra which needs to be taken into account in order to correctly identify the radionuclides present. These effects are shown to be compounded due to the subsequent shift in the photon spectra produced by the detector, in this case an inorganic solid scintillator (CaF2:Eu) monitored using a Silicon Photomultiplier (SiPM). Using tritiated water as an environmentally relevant, and notoriously difficult to monitor case study, analytical predictions for the shift in the energy spectra as a function of depth of source have been derived. These predictions have been validated using Geant4 simulations and experimental results measured using bespoke instrumentation

The Effects of Dual-Task Interference and Response Strategy on Stop or Go Decisions to Yellow Light Changes

Distractions can interfere with driving by causing central processing bottlenecks. In addition to performance decrements, central processing delays may also impair decision-making during critical driving maneuvers such as stop or go decisions at intersections. It was hypothesized that distractions would delay the stop or go decision leading to more go responses. Participants drove 4 simulated drives and made stop or go decisions at intersections with and without a distracting task. Distractions did not result in more go responses at intersections. Additionally, dual-task interference in braking responses was found to be dependent upon participants’ response strategies. Theoretical implications of response strategy on processing bottlenecks were discussed

Adaptations of Escherichia coli strains to oxidative stress are reflected in properties of their structural proteomes.

BACKGROUND:The reconstruction of metabolic networks and the three-dimensional coverage of protein structures have reached the genome-scale in the widely studied Escherichia coli K-12 MG1655 strain. The combination of the two leads to the formation of a structural systems biology framework, which we have used to analyze differences between the reactive oxygen species (ROS) sensitivity of the proteomes of sequenced strains of E. coli. As proteins are one of the main targets of oxidative damage, understanding how the genetic changes of different strains of a species relates to its oxidative environment can reveal hypotheses as to why these variations arise and suggest directions of future experimental work. RESULTS:Creating a reference structural proteome for E. coli allows us to comprehensively map genetic changes in 1764 different strains to their locations on 4118 3D protein structures. We use metabolic modeling to predict basal ROS production levels (ROStype) for 695 of these strains, finding that strains with both higher and lower basal levels tend to enrich their proteomes with antioxidative properties, and speculate as to why that is. We computationally assess a strain's sensitivity to an oxidative environment, based on known chemical mechanisms of oxidative damage to protein groups, defined by their localization and functionality. Two general groups - metalloproteins and periplasmic proteins - show enrichment of their antioxidative properties between the 695 strains with a predicted ROStype as well as 116 strains with an assigned pathotype. Specifically, proteins that a) utilize a molybdenum ion as a cofactor and b) are involved in the biogenesis of fimbriae show intriguing protective properties to resist oxidative damage. Overall, these findings indicate that a strain's sensitivity to oxidative damage can be elucidated from the structural proteome, though future experimental work is needed to validate our model assumptions and findings. CONCLUSION:We thus demonstrate that structural systems biology enables a proteome-wide, computational assessment of changes to atomic-level physicochemical properties and of oxidative damage mechanisms for multiple strains in a species. This integrative approach opens new avenues to study adaptation to a particular environment based on physiological properties predicted from sequence alone