Application of computational fluid dynamics to complex inlet ducts

A three-dimensional parabolic Navier-Stokes code, PEPSIG, was used to analyze the flow in the subsonic diffuser section of a typical modern inlet design. The effect of curvature of the diffuser centerline and transitioning cross sections was studied to determine the primary cause of flow distortion in the duct. Total pressure values at the engine compressor face are reported

MOLECULAR CHARACTERIZATION OF FREE TROPOSPHERIC ORGANIC AEROSOL AND THE DEVELOPMENT OF COMPUTATIONAL TOOLS FOR MOLECULAR FORMULA ASSIGNMENT

Organic aerosol affects human health and climate. These effects are largely determined by the composition of the organic aerosol, which is a complex mixture of species. Understanding the complexity of organic aerosol is critical to determining its effect on human health and climate. In this study, long range transported organic aerosol collected at the Pico Mountain Observatory was analyzed using ultrahigh resolution mass spectrometry. Organic aerosol transported in the free troposphere had an overall lower extent of oxidation than aerosol transported in the boundary layer. It was hypothesized that the lower oxidation was related to a more viscous phase state of the aerosol during transport. The results suggest that biomass burning organic aerosol injected into the free troposphere are more persistent than organic aerosol in the boundary layer. A sample was also analyzed using tandem FT-ICR MS/MS fragmentation, providing information about the functional group composition in the aerosol sample. This was done using a segmented scan approach, which revealed an unprecedented molecular complexity of unfragmented precursor ions. In addition to the expected CO2 and H2O neutral losses, neutral losses corresponding to carbonyl functional groups (C2H4O, CO) were observed. The abundance of carbonyl functional groups suggests a slower rate of aging in the atmosphere. Analysis of nitrogen and sulfur containing neutral losses highlighted a surprising abundance of reduced nitrogen and sulfur loss (NH3 and SH2). This further supports the hypothesis of slower aging in the free troposphere. Additional research was done to develop an R software package (MFAssignR) to perform molecular formula assignment with improved decision-making transparency, noise estimation, isotope identification, and mass recalibration. MFAssignR was found to assign the same molecular formula as other molecular formula assignment methods for the majority (97-99%) of mass peaks that were assigned a molecular formula by the compared methods. Additionally, MFAssignR was more effective at assigning molecular formulas to low intensity peaks relative to the other methods tested, leading to more overall molecular formula assignments. MFAssignR is available via GitHub and is the first open source package to contain a full pipeline of functions for data preparation and analysis for ultrahigh resolution mass spectrometry

Research turbine for high-temperature core engine application. 2: Effect of rotor tip clearance on overall performance

A 25.4-cm (10-in) tip diameter turbine was tested to determine the effect of rotor radial tip clearance on turbine overall performance. The test turbine was a half-scale model of a 50.8-cm-(20-in.-) diameter research turbine designed for high-temperature core engine application. The test turbine was fabricated with solid vanes and blades with no provision for cooling air and tested at much reduced inlet conditions. The tests were run at design speed over a range of pressure ratios for three different rotor clearances ranging from 2.3 to 6.7 percent of the annular blade passage height. The results obtained are compared to the results obtained with three other turbines of varying amounts of reaction

A Review of a Case Against Blaise Pascal and His Heirs

A Review of The Probable and the Provable by L. Jonathan Cohe

The Factors That Motivated American Ground Forces to Fight during Combat in Vietnam

Many people debate the policies of the United States government with respect to the conduct of the Vietnam War. The war was unpopular, at best, and many argued that our military should not have fought for South Vietnam. So, what compelled American ground forces to fight an atypical enemy? This thesis explores the motivational factors that influenced the military ground forces on a daily basis. Past research conducted on previous wars serves as the guideline for the methodology used. Combat narratives are the data sources and references to motivational factors by the authors are the data. As a whole, the narratives examined in this study reveal that primary group, combat survival, leadership, and duty were all significant motivating factors with none of the four heavily outweighing the others. Additionally, the narratives were categorized with respect to the characteristics of the author and the author\u27s combat experience. Of those categories, rank produced the most significant differences among motivational factors between groups. Leadership was a prominent motivating factor for officers while enlisted men fought for the good of the primary group and for combat survival

Entry-level student affairs administrators\u27 attitudes toward mental illness in college students.

Calls for universities to better serve college students with mental illness have been growing. While a considerable literature base supports Corrigan\u27s (2004) Social Cognitive Model of Mental Illness Stigma and the complex relationship among stereotypes, prejudice, and discrimination, limited research has been conducted examining university administrators on attitudes toward and knowledge of mental illness in college students. Participants of the current study were 206 entry-level student affairs professionals who completed an online, modified version of Becker, Martin, Wajeeh, Ward, and Shern\u27s (2002) Mental Illness Awareness Survey. Simultaneous regression was used to determine the significance of seven demographic variables (gender, age, ethnicity, level of education, type of university, university enrollment size, and years of experience) on five dependent variables: fear towards students with mental illness, confidence in ability to help students with mental illness, awareness of campus services, referrals to campus services, and knowledge of psychological disabilities. None of the five regression models were significant, likely due to a restriction of range in several independent variables in the entry-level study population. Three independent variables were significant at the p \u3c .01 level, including employment at a large university on fear, and years of experience and possession of a master\u27s degree on awareness of campus services. Compared to faculty responses on the instrument in an earlier study (Becker et al., 2002), entry-level student affairs professionals demonstrated a trend towards more positive attitudes and knowledge. Findings suggest that administrators desire continued education on mental illness in college students, particularly on disorders including schizophrenia, personality disorders, and paranoia, as well as disorders more commonly seen and/or on the rise in college students such as attention deficit hyperactivity disorder, eating disorders, bipolar disorder, and posttraumatic stress disorder. Recommendations are offered for graduate preparation programs and professional development workshops. Current study limitations and gaps in the literature can be addressed in future research using broader student affairs populations while examining disclosure in social media, factors related to effective referrals, and student perceptions of discrimination

Effect of variable stator area on performance of a single-stage turbine suitable for air cooling. 1 - Stator overall performance with 130-percent design area

Effect of variable stator geometry on performance of air cooling turbin

Cold-air investigation of a turbine for high temperature-engine application. 5: Two-stage turbine performance as affected by variable stator area

The stator areas of the design two-stage turbine were both decreased and increased by nominally 30 percent, and the performances of the two turbines are compared with that of the design stator area turbine. Turbine efficiency decreased with stator area changes. Closing the stator area resulted in the more severe efficiency loss. The decrease in efficiency for both turbines is attributable to rotor incidence, off-design blade-surface velocities, and adverse reaction changes across the blade rows

The Time Course of Acoustic/Phonemic Cue Integration in the Sensorineural Hearing-Impaired.

It has been documented that phonemic featural information is differentially distributed across time in the speech waveform. It is also known that listeners with sensorineural hearing impairment often make errors on phoneme identification tasks. However, there is little documentation available that describes how the hearing-impaired listener uses the various sources of phonemic information which are distributed in the speech waveform. In this investigation, a group of normal hearing listeners and a group of sensorineural hearing-impaired listeners (with and without the benefit of amplification) identified various consonant and vowel productions that had been systematically varied in duration. The consonants (presented in a /haCa/ environment) and the vowels (presented in a /bVd/ environment) were truncated in steps to allow additional sequential segments of the original waveform to be presented. The results indicated that normal hearing listeners could extract more phonemic information from the earlier occurring positions of the stimulus waveforms, especially consonantal place information, than could the hearing-impaired listeners. For the hearing-impaired listeners in the unaided condition, percent correct identification for the consonant stimuli was lower than that for the normal hearing subjects, even for the full-duration stimuli, although the gap between impaired-unaided and normal performance decreased as truncation times increased. For vowel stimuli, impaired-unaided performance approached that of the normal hearing subjects for the full-duration stimuli, although significant performance gaps were apparent at shorter stimulus durations. The use of amplification did decrease the performance differences between the normal hearing listeners and the unaided hearing-impaired listeners. Yet, in many cases, even while using amplification, the hearing-impaired listeners could not make full use of the early-occurring feature information. The results are relevant to current models of normal speech perception which emphasize the need for the listener to make phonemic identification as quickly as possible