The effects of winglets on low aspect ratio wings at supersonic Mach numbers

A computational study was conducted on two wings, of aspect ratios 1.244 and 1.865, each having 65 degree leading edge sweep angles, to determine the effects of nonplanar winglets at supersonic Mach numbers. A Mach number of 1.62 was selected as the design value. The winglets studied were parametrically varied in alignment, length, sweep, camber, thickness, and dihedral angle to determine which geometry had the best predicted performance. For the computational analysis, an available Euler marching technique was used. The results indicated that the possibility existed for wing-winglet geometries to equal the performance of wing-alone bodies in supersonic flows with both bodies having the same semispan. The first wing with winglet used NACA 1402 airfoils for the base wing and was shown to have lift-to-pressure drag ratios within 0.136 percent to 0.360 percent of the NACA 1402 wing-alone. The other base wing was a natural flow wing which was previously designed specifically for a Mach number of 1.62. The results obtained showed that the natural wing-alone had a slightly higher lift-to-pressure drag than the natural wing with winglets

Experimental evaluation of transonic stators, data and performance report, multiple circular arc stator B

Transonic stator with multiple circular arc airfoils and minimum curvature tested over range of flow angles and velocities - stator

Experimental Evaluation of Transonic Stators, Data and Performance Report, Double Circular Arc Stator

Transonic stator with double circular arc airfoils tested over range of flow angles and velocitie

Isolation of tributyltin-degrading bacteria citrobacter braakii and enterobacter cloacae from butyltin-polluted sediment

Tributyltin compound (TBT) released into the aquatic environment is generally degraded by bacteria in water and sediment. The isolation of TBT-degrading bacteria from TBT polluted sediment leads to the indication of specific potential TBT degraders. Two new strains of bacteria designated as B2 and B3 were successfully isolated using glycerol medium containing tributyltin chloride (TBTC) at 130 μM from contaminated sediment collected from Bowling Basin in Glasgow. The observed degradation after 14 days of the microcosm from the sediment and the isolated bacteria were investigated at an initial concentration of 1 μM TBTC. It was found that TBT was degraded by the bacterial strains B2 and B3 at 8.3 and 16.9 %, respectively. The results indicate that B2 and B3 are effective as TBT degraders. EC50 of B2 and B3 in water were 88.73 and 112.53 μM TBTC, which were significantly higher than the concentration of TBT measured at the basin, suggesting a low effect of TBT on the growth and activity of bacteria. After identification using API 20E and 16S sequencing, the bacterial isolate strain B2 is Citrobacter braakii and B3 is Enterobacter cloacae. Therefore, this study has discovered two species of high resistance TBT degrader which have never been previously studied or isolated based upon TBT degradation ability

Radiative rates and electron impact excitation rates for transitions in He II

We report calculations of energy levels, radiative rates, collision strengths, and effective collision strengths for transitions among the lowest 25 levels of the n <= 5 configurations of He~II. The general-purpose relativistic atomic structure package (GRASP) and Dirac atomic R-matrix code (DARC) are adopted for the calculations. Radiative rates, oscillator strengths, and line strengths are reported for all electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), and magnetic quadrupole (M2) transitions among the 25 levels. Furthermore, collision strengths and effective collision strengths are listed for all 300 transitions among the above 25 levels over a wide energy (temperature) range up to 9 Ryd (10**5.4 K). Comparisons are made with earlier available results and the accuracy of the data is assessed.Comment: 30 pages of text including 12 figures and 5 Tables will appear in ATOMS 5 (2017

Extreme ultraviolet emission lines of Ni XII in laboratory and solar spectra

Wavelengths for emission lines arising from 3s23p5-3s3p6 and 3s23p5-3s23p43d transitions in Ni XII have been measured in extreme ultraviolet spectra of the Joint European Torus(JET) tokamak. The 3s23p5 2P1/2-3s23p4(3P)3d 2D3/2 line is found to lie at 152.90 ± 0.02 A, a significant improvement over the previous experimental determination of 152.95 ± 0.5 A. This new wavelength is in good agreement with a solar identification at 152.84 ± 0.06 A, confirming the presence of this line in the solar spectrum. The Ni XII feature at 152.15 A may be a result only of the 3s23p5 2P3/2-3s23p4(3P)3d 2D5/2 transition, rather than a blend of this line with 3s23p5 2P3/2-3s23p (3P)3d 2P1/2, as previously suggested. Unidentified emission lines at 295.32 and 317.61 A in solar flare spectra from the Skylab mission are tentatively identified as the 3s23p5 2P3/2-3s3p6 2S1/2 and 3s23p5 2P1/2-3s3p6 2S1/2 transitions in Ni XII, which have laboratory wavelengths of 295.33 and 317.50 A, respectively. Additional support for these identifications is provided by the line intensity ratio for the solar features, which shows good agreement between theory and observation

Inorganic chemical oxygen demand of re-suspended sediments in a bar-built lagoon

Rapid dissolved oxygen (DO) depletion, caused by inorganic chemical oxygen demand (COD) of re-suspended sediment compounds, has been documented in few studies, yet fish kills occur often from the process. Pescadero Lagoon, California, USA, a bar-built lagoon that suffers annual fish kills caused by rapid mixing-induced hypoxia upon sandbar breach, was studied to investigate the potential for COD of re-suspended sediment to deplete oxygen. In-situ chamber mixing trials demonstrated that re-suspended sediment can exert powerful oxygen demand on receiving waters. Surface DO depletion upon bar breach was too severe to be explained solely by mixing of the anoxic hypolimnion into the water column, and the depletion was too rapid to be attributed to biochemical oxygen demand (BOD), making COD of re-suspended sediment the likely direct cause. Sedimentous iron and sulfur compounds that exert COD are reduced under anoxic conditions created by water column stratification and BOD of heterotrophic bacteria

Motivational and Persistence Factors for Military Spouses Earning a College Degree

Projections estimated that nontraditional student enrollment in post-secondary education would increase by 19% as compared to traditional student enrollments of 10% from 2006 through 2017. Adult students were less likely to complete a college degree compared to traditional students, and drop-outs cost taxpayers billions of dollars in lost taxes. Military spouses were a sub-group of nontraditional students with unique challenges and stressors due to their military lifestyle. Limited research-based literature existed on military spouses enrolled in post-secondary education. Financial incentives such as My Career Advancement Account (MyCAA) and the transferability of the Post-9/11 GI Bill enabled military spouses to participate in post-secondary education at unprecedented numbers. This research study sought to determine factors that motivated and enabled military spouses to earn a college degree. The research questions guiding this study included: (1) What factors motivated military spouses to earn a college degree? (2) What factors enabled military spouses to persist in earning a college degree? and (3) What factors needed to be known by colleges and universities to assist military spouses in earning a college degree? Data for this study were collected using a survey that included closed-form Likert-scale questions, open-form questions, and demographic questions. Seven hundred fifty-two military spouse students completed the survey. Descriptive statistics and multiple regression analyses were used to address the research questions. The findings of this study indicated that personal fulfillment/satisfaction, college degree is a necessary career requirement, enjoy learning for the sake of learning, and the college/university accommodates \u27my\u27 developmental needs were significant factors for military spouses\u27 motivation to earn a college degree. The factor support and encouragement from other people (family, friends, or co-workers) was identified as the significant persistence factor for military spouses earning a college degree. These five factors were further explained as the factors that colleges and universities needed to know to assist military spouses in earning a college degree. Colleges and universities with military spouse populations should consider evaluating their programs and services to examine if they support adult developmental needs and use the findings from this study to enhance recruiting and retention strategies for military spouses