Aerodynamic characteristics of a distinct wing-body configuration at Mach 6: Experiment, theory, and the hypersonic isolation principle

An experimental investigation has been conducted to determine the effect of wing leading edge sweep and wing translation on the aerodynamic characteristics of a wing body configuration at a free stream Mach number of about 6 and Reynolds number (based on body length) of 17.9 x 10 to the 6th power. Seven wings with leading edge sweep angles from -20 deg to 60 deg were tested on a common body over an angle of attack range from -12 deg to 10 deg. All wings had a common span, aspect ratio, taper ratio, planform area, and thickness ratio. Wings were translated longitudinally on the body to make tests possible with the total and exposed mean aerodynamic chords located at a fixed body station. Aerodynamic forces were found to be independent of wing sweep and translation, and pitching moments were constant when the exposed wing mean aerodynamic chord was located at a fixed body station. Thus, the Hypersonic Isolation Principle was verified. Theory applied with tangent wedge pressures on the wing and tangent cone pressures on the body provided excellent predictions of aerodynamic force coefficients but poor estimates of moment coefficients

Voices of Native Resiliency: Educational Experiences from the 1950s and 1960s

The purpose of this study was to examine the lived educational experiences of American Indians who grew up during the 1950s and 1960s, known as the termination period in American history. The research for this phenomenological study consisted of interviews with eight participants who were willing to share their personal experiences from this selected time. Ten reoccurring themes were uncovered: chaos brings balance, challenge to become bi-cultural, the importance of teachers, external support systems, spirituality, tribal influences, influences of economic resources, cultural awareness and value, relevant curriculum, and recruitment of Native teachers. By uncovering these stories, it is hopeful that educators would benefit by being able to further illuminate and contextualize an understanding for more culturally responsive pedagogy

Aerodynamic characteristics of a hypersonic research airplane concept having a 70 deg swept double-delta wing at Mach number 0.2

A wind-tunnel of the static longitudinal, lateral and directional stability characteristics of a hypersonic research airplane concept having a 70 deg swept double-delta wing was conducted in the Langley low-turbulence pressure tunnel. The configuration variables included wing planform, tip fins, center fin, and scramjet engine modules. A mach number of 0.2 was investigated over a Reynolds number (based on fuselage length) range of 2,200,000 to 19.75 x 1,000,000 (with a majority of tests at 10.0 x 1,000,000. Tests were conducted through an angle-of-attack range from about -2 deg to 34 deg at angles of sideslip of 0 deg to 5 deg, and at elevon deflection of 0 deg, -5 deg, -10 deg, -15 deg, and -20 deg. The drag coefficient of the integrated scramjet engine appears relatively constant with Reynolds number at the test Mach number of 0.2. Mild pitch-up was exhibited by the models equipped with tip fins. The forward delta, a highly swept forward portion of the wing, was destabilizing. The center fin model has a higher trimmed maximum lift-drag ratio and a wider trim lift and angle-of-attack range than the tip fin model. Both the tip fin models and center fin models exhibited positive dihedral effect and positive directional stability. Roll control was positive for the tip fin model, but yaw due to roll control was unfavorable

Glassy Dynamics of Protein Methyl Groups Revealed by Deuteron NMR

We investigated site-specific dynamics of key methyl groups in the hydrophobic core of chicken villin headpiece subdomain (HP36) over the temperature range between 298 and 140 K using deuteron solid-state NMR longitudinal relaxation measurements. The relaxation of the longitudinal magnetization is weakly nonexponential (glassy) at high temperatures and exhibits a stronger degree of nonexponentiality below about 175 K. In addition, the characteristic relaxation times deviate from the simple Arrhenius law. We interpret this behavior via the existence of distribution of activation energy barriers for the three-site methyl jumps, which originates from somewhat different methyl environments within the local energy landscape. The width of the distribution of the activation barriers for methyl jumps is rather significant, about 1.4 kJ/mol. Our experimental results and modeling allow for the description of the apparent change at about 175 K without invoking a specific transition temperature. For most residues in the core, the relaxation behavior at high temperatures points to the existence of conformational exchange between the substates of the landscape, and our model takes into account the kinetics of this process. The observed dynamics are the same for dry and hydrated protein. We also looked at the effect of F58L mutation inside the hydrophobic core on the dynamics of one of the residues and observed a significant increase in its conformational exchange rate constant at high temperatures

Aerodynamic characteristics of a hypersonic research airplane concept having a 70 deg swept double-delta wing at Mach numbers from 0.80 to 1.20, with summary of data from 0.20 to 6.0

The static longitudinal, lateral, and directional stability characteristics of a hypersonic research airplane concept having a 70 deg swept double-delta wing were investigated. Force tests were conducted in the Langley 8 foot transonic pressure tunnel for a Reynolds number (based on fuselage length) range of 6.30 x 10 to the 6th power to 7.03 x 10 to the 6th power, at angles of attack from about -4 deg to 23 deg, and at angles of sideslip of 0 deg and 5 deg. The configuration variables included the wing planform, tip fins, the center vertical tail, and scramjet engine modules. Variations of the more important aerodynamic parameters with Mach number for Mach numbers from 0.20 to 6.0 are summarized. A state-of-the-art example of theoretically predicting performance parameters and static longitudinal and directional stability over the Mach number range is included

Linear Stochastic Models of Nonlinear Dynamical Systems

We investigate in this work the validity of linear stochastic models for nonlinear dynamical systems. We exploit as our basic tool a previously proposed Rayleigh-Ritz approximation for the effective action of nonlinear dynamical systems started from random initial conditions. The present paper discusses only the case where the PDF-Ansatz employed in the variational calculation is ``Markovian'', i.e. is determined completely by the present values of the moment-averages. In this case we show that the Rayleigh-Ritz effective action of the complete set of moment-functions that are employed in the closure has a quadratic part which is always formally an Onsager-Machlup action. Thus, subject to satisfaction of the requisite realizability conditions on the noise covariance, a linear Langevin model will exist which reproduces exactly the joint 2-time correlations of the moment-functions. We compare our method with the closely related formalism of principal oscillation patterns (POP), which, in the approach of C. Penland, is a method to derive such a linear Langevin model empirically from time-series data for the moment-functions. The predictive capability of the POP analysis, compared with the Rayleigh-Ritz result, is limited to the regime of small fluctuations around the most probable future pattern. Finally, we shall discuss a thermodynamics of statistical moments which should hold for all dynamical systems with stable invariant probability measures and which follows within the Rayleigh-Ritz formalism.Comment: 36 pages, 5 figures, seceq.sty for sequential numbering of equations by sectio

Establishment and Propagation of Human Retinoblastoma Tumors in Immune Deficient Mice

Culturing retinoblastoma tumor cells in defined stem cell media gives rise to primary tumorspheres that can be grown and maintained for only a limited time. These cultured tumorspheres may exhibit markedly different cellular phenotypes when compared to the original tumors. Demonstration that cultured cells have the capability of forming new tumors is important to ensure that cultured cells model the biology of the original tumor

Forecasts of Opportunity for Northern California Soil Moisture

Soil moisture anomalies underpin a number of critical hydrological phenomena with socioeconomic consequences, yet systematic studies of soil moisture predictability are limited. Here, we use a data-adaptive technique, Linear Inverse Modeling, which has proved useful as an indication of predictability in other fields, to investigate the predictability of soil moisture in northern California. This approach yields a model of soil moisture at 10 stations in the region, with results that indicate the possibility of skillful forecasts at each for lead times of 1&ndash;2 weeks. An important advantage of this model is the a priori identification of forecasts of opportunity&mdash;conditions under which the model&rsquo;s forecasts may be expected to have particularly high skill. Given that forecast errors (and inversely, their skill) can be estimated in advance, these findings have the potential to greatly increase the utility of soil moisture forecasts for practical applications including drought and flood forecasting.</p

Prediction and validation of exenatide risk marker effects on progression of renal disease:Insights from EXSCEL

Aim To assess whether the previously developed multivariable risk prediction framework (PRE score) could predict the renal effects observed in the EXSCEL cardiovascular outcomes trial using short-term changes in cardio-renal risk markers. Materials and Methods Changes from baseline to 6 months in HbA1c, systolic blood pressure (SBP), body mass index (BMI), haemoglobin, total cholesterol, and new micro- or macroalbuminuria were evaluated. The renal outcomes were defined as a composite of a sustained 30% or 40% decline in estimated glomerular filtration rate (eGFR) or end-stage renal disease (ESRD). Relationships between risk markers and long-term renal outcomes were determined in patients with type 2 diabetes from the ALTITUDE study using multivariable Cox regression analysis, and then applied to short-term changes in risk markers observed in EXSCEL to predict the exenatide-induced impact on renal outcomes. Results Compared with placebo, mean HbA1c, BMI, SBP and total cholesterol were lower at 6 months with exenatide, as was the incidence of new microalbuminuria. The PRE score predicted a relative risk reduction for the 30% eGFR decline + ESRD endpoint of 11.3% (HR 0.89; 95% CI 0.83-0.94), compared with 12.7% (HR 0.87; 0.77-0.99) observed risk reduction. For the 40% eGFR decline + ESRD endpoint, the predicted and observed risk reductions were 11.0% (HR 0.89; 0.82-0.97) and 13.7% (HR 0.86, 0.72-1.04), respectively. Conclusions Integrating short-term risk marker changes into a multivariable risk score predicted the magnitude of renal risk reduction observed in EXSCEL

Performance of a 500 watt Nd:GGG zigzag slab oscillator

Realization of practical multi-kilowatt Nd:garnet lasers will require the scale-up of crystal dimensions as well as more powerful pumping sources. A high average power zigzag slab crystal amplifier testing facility has been established at LLNL which employs two 100 kW{sub e} vortex stabilized arc lamps, cooled reflectors and a cooled, spectrally filtered, crystal slab mounting fixture. The operational characteristics of the first crystal laser to be tested in this setup, a Nd:GGG zigzag oscillator, are presented. A Nd:GGG crystal of dimensions 18 {times} 7 {times} 0.5 cm{sup 3}, doped at 2 {times} 10{sup 20} cm{sup {minus}3} Nd{sup 3+} atomic density, was pumped by up to 40 kW of filtered argon line emission. A small-signal single pass gain (losses excluded) of 1.09 was measured with a probe laser when the DC input to the lamps was 43 kW{sub e}. Our power supply was then modified to operate in a pulsed mode and provided one to three milliseconds pulses at 120 Hz. An average optical output power of 490 watts was obtained at a lamp input power of 93 kW{sub e} in an unoptimized resonator. The laser output power declined after a few tens of seconds since the slab tips were not properly cooled. A birdhouse specular lamp reflector and a contoured diffuse reflector were tested; in both cases the pump illuminated crystal surface was smaller than the total crystal face area. Fluorescence imaging of the zigzag amplifier's output aperture registered a smoother, more uniform pumping profile when the diffuse reflector was used. Uniformity of pumping results in decreased resonator loss and yields higher laser output power. Thermo-optic distortions observed in these preliminary tests are analyzed with the aid of computer simulations of the thermal fields, stresses, and surface displacements of our crystal slab. 3 refs., 12 figs