Calculation of shock-separated turbulent boundary layers

Numerical solutions of the complete, time-averaged conservation equations using several eddy-viscosity models for the Reynolds shear stress to close the equations are compared with experimental measurements in a compressible, turbulent separated flow. An efficient time-splitting, explicit difference scheme was used to solve the two-dimensional conservation equations. The experiment used for comparison was a turbulent boundary layer that was separated by an incident shock wave in a Mach 2.93 flow with a unit Reynolds number of 5.7 x 10 to the seventh power m. Comparisons of predicted and experimental values of surface pressure, shear stress along the wall, and velocity profiles are shown. One of the tested eddy-viscosity models which allows the shear stress to be out of equilibrium with the mean flow produces substantially better agreement with the experimental measurements than the simpler models. A tool is thereby provided for inferring additional information about the flow, such as static pressures in the stream, which might not be directly obtainable from experiments

Measurements of some parameters of thermal sparks with respect to their ability to ignite aviation fuel/air mixtures

A method used to generate thermal sparks for experimental purposes and methods by which parameters of the sparks, such as speed, size, and temperature, were measured are described. Values are given of the range of such parameters within these spark showers. Titanium sparks were used almost exclusively, since it is particles of this metal which are found to be ejected during simulation tests to carbon fiber composite (CFC) joints. Tests were then carried out in which titanium sparks and spark showers were injected into JP4/(AVTAG F40) mixtures with air. Single large sparks and dense showers of small sparks were found to be capable of causing ignition. Tests were then repeated using ethylene/air mixtures, which were found to be more easily ignited by thermal sparks than the JP4/ air mixtures

Dual-Energy X-Ray Absorptiometry for Determination of Body Composition in a Porcine Model of Obesity Development

To determine the efficacy of bioactive molecules for minimizing body fat accretion in mammals, an effective method for measuring changes in body fat must be used. In the current study, the precision and accuracy of the Dual Energy X-ray Absorptiometry (DEXA) estimates of the weight and tissue (fat, lean and bone mineral) content of two body depots (carcass and internal organs) were evaluated in heavy weight pigs (133-265 kg) serving as an obesity development model. DEXA accurately estimated carcass weight, but underestimated the fat tissue contents and overestimated the lean tissue contents of both the carcass and organ depots relative to those estimated from chemical analysis of the fat and protein contents of the depots. However, DEXA precisely detected changes in carcass and organ depot weights (R2 = .99, .99 respectively) and less precisely detected changes in the depot’s chemically determined fat (R2 = .95, .73) and protein content (R2 = .88, .84). Specifically, for each 1 kg change in carcass and organ depot weights, DEXA predicted the changes with a 95 % confidence (2 SE of estimate) within ± .008 and .026 kg, respectively. For each 1 kg change in the two depot’s chemically determined fat content, DEXA predicted the change within ± .092 and .338 kg, respectively. In conclusion, DEXA is a method that can precisely detect changes in body composition in large, heavy weight pigs being used in a model of obesity development.

Efficacy of Pantothenic Acid as a Modifier of Body Composition in a Porcine Model of Obesity Development

Our group’s previous research has shown that pantothenic acid (PA) fed in amounts above that needed to maximize body growth effectively reduce fat tissue accretion in pigs. In the current study, the efficacy of PA to minimize fatty tissue accretion in a porcine model of obesity development was determined. Heavy weight pigs (156 kg) were allotted to one of four dietary regimens consisting of a basal diet (8 ppm PA) supplemented with 0, 80, 800, 8000 ppm added PA. The basal diet contained a dietary nutrient mix representative of the American diet (34 % of calories from fat) at daily caloric intakes equivalent to 1.8 times the animal’s maintenance needs for 144 days. A state of obesity development occurred over the duration of the study. Specifically, pigs accrued 73 kg of body weight, of which 48 % was fat tissue. Whole body fat tissue content responded quadratically to increasing PA additions. Body fat percentage was reduced by .9 percentage units by the 80 ppm added PA and increased by 1.6 and 1.1 percentage units by the 800 and 8000 ppm added PA. Based on these data, PA is not an efficient modifier of body composition in a porcine model of obesity development induced by a high fat dietary regimen

Imaging internal flows in a drying sessile polymer dispersion drop using Spectral Radar Optical Coherence Tomography (SR-OCT)

In this work, we present the visualization of the internal flows in a drying sessile polymer dispersion drop on hydrophilic and hydrophobic surfaces with Spectral Radar Optical Coherence Tomography (SR-OCT).We have found that surface features such as the initial contact angle and pinning of the contact line, play a crucial role on the flow direction and final shape of the dried drop. Moreover, imaging through selection of vertical slices using optical coherence tomography offers a feasible alternative compared to imaging through selection of narrow horizontal slices using confocal microscopy for turbid, barely transparent fluids

Deriving bases for Abelian functions

We present a new method to explicitly define Abelian functions associated with algebraic curves, for the purpose of finding bases for the relevant vector spaces of such functions. We demonstrate the procedure with the functions associated with a trigonal curve of genus four. The main motivation for the construction of such bases is that it allows systematic methods for the derivation of the addition formulae and differential equations satisfied by the functions. We present a new 3-term 2-variable addition formulae and a complete set of differential equations to generalise the classic Weierstrass identities for the case of the trigonal curve of genus four.Comment: 35page

Experimental study of optimal measurements for quantum state tomography

Quantum tomography is a critically important tool to evaluate quantum hardware, making it essential to develop optimized measurement strategies that are both accurate and efficient. We compare a variety of strategies using nearly pure test states. Those that are informationally complete for all states are found to be accurate and reliable even in the presence of errors in the measurements themselves, while those designed to be complete only for pure states are far more efficient but highly sensitive to such errors. Our results highlight the unavoidable tradeoffs inherent to quantum tomography.Comment: 5 pages, 3 figure

Inheritance of Black Hair Patterns in Cattle Lacking the Extension Factor for Black (E.). IV, Partitioning Phenotypes by Castration

Author Institution: Department of Dairy Science, Ohio Agricultural Experiment Station, Wooste

Toxicity of thermal degradation products of spacecraft materials

Three polymeric materials were evaluated for relative toxicity of their pyrolysis products to rats by inhalation: Y-7683 (LS 200), Y-7684 (Vonar 3 on Fiberglass), and Y-7685 (Vonar 3 on N W Polyester). Criteria employed for assessing relative toxicity were (1) lethality from in-chamber pyrolysis, (2) lethality from an outside-of-chamber pyrolysis MSTL Procedure, and (3) disruption of trained rats' shock-avoidance performance during sub-lethal exposures to in-chamber pyrolysis of the materials