Massively-parallel Spectral Element Algorithm Development for High Speed Flows

The need to reduce both the time and cost of product design has allowed numerical analysis to play an ever-increasing role in design cycle analysis. This is particularly true in the aerospace industry, where the use of computational fluid dynamics can help reduce the need for costly prototype testing. Due to the extremely high computational costs associated with simulating complex industrial flows directly, most modern simulation tools employ solvers that rely heavily on turbulence modeling. However, the combination of modern supercomputers and algorithms that can take full advantage of them allows for higher fidelity solvers, with reduced dependence on turbulence modeling, to be included in design cycle analysis. This work employs the discontinuous Galerkin spectral element method in a solver designed for high fidelity simulations in the subsonic and transonic flow regimes. The algorithm is implemented using NEK5000, an open-source incompressible spectral element solver, as a code base. Details of the algorithm are given, and the code is validated against several canonical inviscid and viscous test cases. The validation cases show that the code is accurate, stable, and a good performer on supercom- puters. The new solver is then used to study the effectiveness of a cylindrical film cooling hole. The results show a much improved prediction capability of film cooling effectivness as compared to previous low-Mach simulation results. The algorithm is proven to produce quality large-eddy simulation data in a time frame accessible for design cycle analysis. At the end, a suggested direction for future development of the algorithm is discussed, with a focus on how to improve the stability and performance of the solver

Massively-Parallel Spectral Element Large Eddy Simulation of a Ring-Type Gas Turbine Combustor

The average and fluctuating components in a model ring-type gas turbine combustor are characterized using a Large Eddy Simulation at a Reynolds number of 11,000, based on the bulk velocity and the mean channel height. A spatial filter is applied to the incompressible Navier-Stokes equations, and a high pass filtered Smagorinsky model is used to model the sub-grid scales. Two cases are studied: one with only the swirler inlet active, and one with a single row of dilution jets activated, operating at a momentum flux ratio J of 100. The goal of both of these studies is to validate the capabilities of the solver NEK5000 to resolve important flow features inherent to gas turbine combustors by comparing qualitatively to the work of Jakirlic. Both cases show strong evidence of the Precessing Vortex Core, an essential flow feature in gas turbine combustors. Each case captures other important flow characteristics, such as corner eddies, and in general predicts bulk flow movements well. However, the simulations performed quite poorly in terms of predicting turbulence shear stress quantities. Difficulties in properly emulating the turbulent velocity entering the combustor for the swirl, as well as mesh quality concerns, may have skewed the results. Overall, though small length scale quantities were not accurately captured, the large scale quantities were, and this stress test on the HPF LES model will be built upon in future work that looks at more complex combustors

Generating Keywords Improves Metacomprehension and Self-Regulation in Elementary and Middle School Children

Metacomprehension accuracy is typically quite poor; however, recently interventions have been developed to improve accuracy. In two experiments, we evaluated whether generating delayed keywords prior to judging comprehension improved metacomprehension accuracy for children. For sixth and seventh graders, metacomprehension accuracy was greater for the delayed-keyword condition than for a control group. By contrast, for fourth graders, accuracy did not differ across conditions. Improved metacomprehension accuracy led to improved regulation of study

RELATIONSHIP OF THROWING ARM MECHANICS AND INTERVAL THORWING DISTANCE IN HIGH SCHOOL BASEBALL PLAYERS

Ninety-five high school baseball players (16 ± 1 years; 75 ± 13 kg; and 178 ± 20 cm) threw from flat-ground at distances of 9 m, 18 m, 27 m, 37 m, and 46 m while wearing a motusBASEBALLTM sensor (Motus Global, Massapequa, NY USA). Linear mixed-effects models and likelihood ratio tests were utilized to estimate the within-subject relationship between throwing distance and arm slot, arm speed, shoulder rotation, and elbow varus torque. Increases in throwing distance were accompanied by significant increases in varus torque (��2 = 3509, p\u3c0.01), arm speed (��2 = 5144, p\u3c0.01), and shoulder external rotation (��2 = 3277, p\u3c0.01) and significant decreases in arm slot (��2 = 952, p\u3c0.01). The use of longer distances for training and conditioning are shown to be beneficial in increasing shoulder rotation and arm speed; however, precaution needs to be taken when reaching maximum distances as there is a subsequent increase in elbow varus torque

Epidemiology and Impact of Abdominal Oblique Injuries in Major and Minor League Baseball.

BACKGROUND: Oblique injuries are known to be a common cause of time out of play for professional baseball players, and prior work has suggested that injury rates may be on the rise in Major League Baseball (MLB). PURPOSE: To better understand the current incidence of oblique injuries, determine their impact based on time out of play, and to identify common injury patterns that may guide future injury prevention programs. STUDY DESIGN: Descriptive epidemiological study. METHODS: Using the MLB Health and Injury Tracking System, all oblique injuries that resulted in time out of play in MLB and Minor League Baseball (MiLB) during the 2011 to 2015 seasons were identified. Player demographics such as age, position/role, and handedness were included. Injury-specific factors analyzed included the following: date of injury, timing during season, days missed, mechanism, side, treatment, and reinjury status. RESULTS: A total of 996 oblique injuries occurred in 259 (26%) MLB and 737 (74%) MiLB players. Although the injury rate was steady in MiLB, the MLB injury rate declined (P = .037). A total of 22,064 days were missed at a mean rate of 4413 days per season and 22.2 days per injury. The majority of these occurred during batting (n = 455, 46%) or pitching (n = 348, 35%), with pitchers losing 5 days more per injury than batters (P \u3c .001). The leading side was injured in 77% of cases and took 5 days longer to recover from than trailing side injuries (P = .009). Seventy-nine (7.9%) players received either a corticosteroid or platelet-rich plasma injection, and the mean recovery time was 11 days longer compared with those who did not receive an injection (P \u3c .001). CONCLUSION: Although the rate of abdominal oblique injuries is on the decline in MLB, this is not the case for MiLB, and these injuries continue to represent a significant source of time out of play in professional baseball. The vast majority of injuries occur on the lead side, and these injuries result in the greatest amount time out of play. The benefit of injections for the treatment of oblique injuries remains unknown

SQuId: Measuring Speech Naturalness in Many Languages

Much of text-to-speech research relies on human evaluation, which incurs heavy costs and slows down the development process. The problem is particularly acute in heavily multilingual applications, where recruiting and polling judges can take weeks. We introduce SQuId (Speech Quality Identification), a multilingual naturalness prediction model trained on over a million ratings and tested in 65 locales-the largest effort of this type to date. The main insight is that training one model on many locales consistently outperforms mono-locale baselines. We present our task, the model, and show that it outperforms a competitive baseline based on w2v-BERT and VoiceMOS by 50.0%. We then demonstrate the effectiveness of cross-locale transfer during fine-tuning and highlight its effect on zero-shot locales, i.e., locales for which there is no fine-tuning data. Through a series of analyses, we highlight the role of non-linguistic effects such as sound artifacts in cross-locale transfer. Finally, we present the effect of our design decision, e.g., model size, pre-training diversity, and language rebalancing with several ablation experiments.Comment: Accepted at ICASSP 2023, with additional material in the appendi

Molecular Dynamics Simulations of Glycerol Monooleate Confined between Mica Surfaces

The structure and frictional properties of glycerol monooleate (GMO) in organic solvents, with and without water impurity, confined and sheared between two mica surfaces are examined using molecular dynamics simulations. The structure of the fluid is characterized in various ways, and the differences between systems with nonaggregated GMO and with preformed GMO reverse micelles are examined. Preformed reverse micelles are metastable under static conditions in all systems. In <i>n</i>-heptane under shear conditions, with or without water, preformed GMO reverse micelles remain intact and adsorb onto one surface or another, becoming surface micelles. In dry toluene, preformed reverse micelles break apart under shear, while in the presence of water, the reverse micelles survive and become surface micelles. In all systems under static and shear conditions, nonaggregated GMO adsorbs onto both surfaces with roughly equal probability. Added water is strongly associated with the GMO, irrespective of shear or the form of the added GMO. In all cases, with increasing shear rate, the GMO molecules flatten on the surface, and the kinetic friction coefficient increases. Under low-shear conditions, the friction is insensitive to the form of the GMO added, whereas the presence of water is found to lead to a small reduction in friction. Under high-shear conditions, the presence of reverse micelles leads to a significant reduction in friction, whereas the presence of water increases the friction in <i>n</i>-heptane and decreases the friction in toluene

Amsterdam urban canals contain novel niches for methane-cycling microorganisms

Urbanised environments have been identified as hotspots of anthropogenic methane emissions. Especially urban aquatic ecosystems are increasingly recognised as important sources of methane. However, the microbiology behind these emissions remains unexplored. Here, we applied microcosm incubations and molecular analyses to investigate the methane‐cycling community of the Amsterdam canal system in the Netherlands. The sediment methanogenic communities were dominated by Methanoregulaceae and Methanosaetaceae, with co‐occurring methanotrophic Methanoperedenaceae and Methylomirabilaceae indicating the potential for anaerobic methane oxidation. Methane was readily produced after substrate amendment, suggesting an active but substrate‐limited methanogenic community. Bacterial 16S rRNA gene amplicon sequencing of the sediment revealed a high relative abundance of Thermodesulfovibrionia. Canal wall biofilms showed the highest initial methanotrophic potential under oxic conditions compared to the sediment. During prolonged incubations the maximum methanotrophic rate increased to 8.08 mmol g(DW) (−1) d(−1) that was concomitant with an enrichment of Methylomonadaceae bacteria. Metagenomic analysis of the canal wall biofilm lead to the recovery of a single methanotroph metagenome‐assembled genome. Taxonomic analysis showed that this methanotroph belongs to the genus Methyloglobulus. Our results underline the importance of previously unidentified and specialised environmental niches at the nexus of the natural and human‐impacted carbon cycle

Meta-analysis of genome-wide association studies of asthma in ethnically diverse North American populations.

Asthma is a common disease with a complex risk architecture including both genetic and environmental factors. We performed a meta-analysis of North American genome-wide association studies of asthma in 5,416 individuals with asthma (cases) including individuals of European American, African American or African Caribbean, and Latino ancestry, with replication in an additional 12,649 individuals from the same ethnic groups. We identified five susceptibility loci. Four were at previously reported loci on 17q21, near IL1RL1, TSLP and IL33, but we report for the first time, to our knowledge, that these loci are associated with asthma risk in three ethnic groups. In addition, we identified a new asthma susceptibility locus at PYHIN1, with the association being specific to individuals of African descent (P = 3.9 × 10(-9)). These results suggest that some asthma susceptibility loci are robust to differences in ancestry when sufficiently large samples sizes are investigated, and that ancestry-specific associations also contribute to the complex genetic architecture of asthma