Factors Influencing the Predicted Performance of Advanced Propeller Designs

The assumptions on which conventional propeller aerodynamic performance analyses are based can be seriously violated when advanced high speed propellers are analyzed. Studies were performed using a lifting line representation for the propeller to determine the sensitivity of predicted propeller performance to various assumptions in the analysis. Items studied include the method of determining blade section lift and the effects of blade section drag, camber and blade sweep. The effects of nonuniform flow into the propeller and compressibility were also studied. Comparisons of analytical and experimental results are presented to demonstrate the overall validity of the results

An analytical and experimental comparison of the flow field of an advanced swept turboprop

An argon ion laser velocimeter with four beams was used to measure the detailed flow-field of an advanced eight blade propeller with 45% of tip sweep in an 8x6 foot supersonic wind tunnel. Data were obtained at a free stream Mach number of 0.8, the design advance ratio of 3.06 and a power coefficient of 1.8. Data are presented for inlet flow, exit flow, flow within the blades and flow slightly outside the blade tips. The data are compared to a lifting line theory. In general, the results of the comparison are considered favorable

Outcomes Following Pars Plana Vitrectomy for Severe Ocular Trauma

Purpose: To investigate outcomes and presenting characteristics for subjects undergoing pars plana vitrectomy for ocular trauma. Methods: Retrospective study of 113 patients who underwent pars plana vitrectomy for severe ocular trauma at [name deleted to maintain the integrity of the review process] between 1999 and 2018. Data were collected on age, gender, initial and final visual acuity (LogMAR), mode of injury, type of injury, number of surgeries performed, follow-up duration, type of tamponade, presence of phthisis, and retinal detachment. The Birmingham Eye Trauma Terminology System (BETTS) was employed. Results: We identified assault and contusion injuries to be the most common mode and type of ocular injury in our cohort. Furthermore, through follow-up we noted a varied number of operations required by patients presenting with ocular trauma and a statistically significant improvement in visual acuity from 1.73 (±0.86) LogMAR to 1.17 (±1.03; p <0.01) LogMAR. A statistically significant difference in final visual acuity was also noted between BETTS classified type of injury groups (p < 0.01). Notably, only 7.3% and 8.2% of patients developed phthisis or a persisting retinal detachment, respectively, during follow-up. Conclusion: Our study demonstrates that ocular trauma requiring pars plana vitrectomy can require a varied number of operations with a guarded visual prognosis. However, a small percentage will proceed to develop phthisis following intervention

Correlates of Satisfaction With Life for People Who Identify as Transgender and Sexual Minority

Researchers have focused on understanding factors such as resiliency, medical concerns, and coping skills in the lives of transgender and gender-nonconforming people. However, little research has examined how transgender and gender-nonconforming people cognitively evaluate their own lives. Furthermore, many people who identify as transgender or gender-nonconforming also report a sexual minority identity status. In this study, we sought to understand how aspects of sexual self-concept (i.e., sexual esteem and sexual anxiety), internalized homonegativity, and level of outness about sexual identity correlated to self-appraisals of satisfaction with life (SWL) in a sample of transgender and gender-nonconforming people who identified as sexual minorities. Participants were recruited at a lesbian, gay, bisexual, transgender Pride festival and completed a paper-pencil survey. Results indicated that there was a positive relationship between SWL and sexual esteem and a negative relationship between SWL and sexual anxiety. The relationship between SWL and internalized homonegativity approached significance while level of outness did not appear to be related to SWL. Implications for research and clinical practice are discussed

Strontium optical lattice clocks for practical realization of the metre and secondary representation of the second

We present a system of two independent strontium optical lattice standards probed with a single shared ultra-narrow laser. The absolute frequency of the clocks can be verified by the use of Er:fiber optical frequency comb with the GPS-disciplined Rb frequency standard. We report hertz-level spectroscopy of the clock line and measurements of frequency stability of the two strontium optical lattice clocks.Comment: This is an author-created, un-copyedited version of an article accepted for publication in Meas. Sci. Technol. The publisher is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at doi:10.1088/0957-0233/26/7/07520

Movement correction in DCE-MRI through windowed and reconstruction dynamic mode decomposition

Images of the kidneys using dynamic contrast enhanced magnetic resonance renography (DCE-MRR) contains unwanted complex organ motion due to respiration. This gives rise to motion artefacts that hinder the clinical assessment of kidney function. However, due to the rapid change in contrast agent within the DCE-MR image sequence, commonly used intensity-based image registration techniques are likely to fail. While semi-automated approaches involving human experts are a possible alternative, they pose significant drawbacks including inter-observer variability, and the bottleneck introduced through manual inspection of the multiplicity of images produced during a DCE-MRR study. To address this issue, we present a novel automated, registration-free movement correction approach based on windowed and reconstruction variants of dynamic mode decomposition (WR-DMD). Our proposed method is validated on ten different healthy volunteers’ kidney DCEMRI data sets. The results, using block-matching-block evaluation on the image sequence produced by WR-DMD, show the elimination of 99% of mean motion magnitude when compared to the original data sets, thereby demonstrating the viability of automatic movement correction using WR-DMD

Lubricant study in ultrahigh vacuum and in various gas environments Final report, 26 Jan. 1965 - 15 Mar. 1966

Wear and friction of lubricated and unlubricated stainless steel bearings in sliding and rolling contact in ultrahigh vacuum and various gas environment