Pressure Drop Across Woven Screens Under Uniform and Nonuniform Flow Conditions

Tests were conducted to determine the experimental pressure drop and velocity data for water flowing through woven screens. The types of materials used are dutch twill and square weave fabrics. Pressure drop measures were made at four locations in a rectangular channel. The data are presented as change in pressure compared with the average entry velocity and the numerical relationship is determined by dividing the volumetric flow rate by the screen area open to flow. The equations of continuity and momentum are presented. A computer program listing an extension of a theoretical model and data from that computer program are included

Broad Feshbach resonance in the 6Li-40K mixture

We study the widths of interspecies Feshbach resonances in a mixture of the fermionic quantum gases 6Li and 40K. We develop a model to calculate the width and position of all available Feshbach resonances for a system. Using the model we select the optimal resonance to study the 6Li/40K mixture. Experimentally, we obtain the asymmetric Fano lineshape of the interspecies elastic cross section by measuring the distillation rate of 6Li atoms from a potassium-rich 6Li/40K mixture as a function of magnetic field. This provides us with the first experimental determination of the width of a resonance in this mixture, Delta B=1.5(5) G. Our results offer good perspectives for the observation of universal crossover physics using this mass-imbalanced fermionic mixture.Comment: 4 pages, 2 figure

Design and construction of 2 transonic airfoil models for tests in the NASA Langley C.3-M TCT

As part of a NASA/DFVLR cooperation program two transonic airfoils were tested in the NASA Langley 0.3-m TCT. Model design and construction was carried out by DFVLR. The models designed and constructed performed extremely well under cryogenic conditions. Essentially no permanent changes in surface quality and geometric dimensions occurred during the tests. The aerodynamic results from the TCT tests which demonstrate the large sensitivity of the airfoil CAST 10-Z/DOAZ to Reynolds number changes compared well with results from other facilities at ambient temperatures

High Performance Ultra-light Nuclear Rockets for NEO (Near Earth Objects) Interaction Missions

The performance capabilities and technology features of ultra compact nuclear thermal rockets based on very high power density ({approximately} 30 Megawatts per liter) fuel elements are described. Nuclear rockets appear particularly attractive for carrying out missions to investigate or intercept Near Earth Objects (NEOS) that potentially could impact on the Earth. Many of these NEO threats, whether asteroids or comets, have extremely high closing velocities, i.e., tens of kilometers per second relative to the Earth. Nuclear rockets using hydrogen propellant enable flight velocities 2 to 3 times those achievable with chemical rockets, allowing interaction with a potential NEO threat at a much shorter time, and at much greater range. Two versions of an ultra compact nuclear rocket based on very high heat transfer rates are described: the PBR (Particle Bed Reactor), which has undergone substantial hardware development effort, and MITEE (Miniature Reactor Engine) which is a design derivative of the PBR. Nominal performance capabilities for the PBR are: thermal power - 1000 MW thrust - 45,000 lbsf, and weight - 500 kg. For MITEE, nominal capabilities are: thermal power - 100 MW; thrust {approx} 4500 lbsf, and weight - 50 kg. Development of operational PBR/MITEE systems would enable spacecraft launched from LEO (Low Earth Orbit) to investigate intercept NEO`s at a range of {approximately} 100 million kilometers in times of {approximately} 30 days

A high-flux 2D MOT source for cold lithium atoms

We demonstrate a novel 2D MOT beam source for cold 6Li atoms. The source is side-loaded from an oven operated at temperatures in the range 600<T<700 K. The performance is analyzed by loading the atoms into a 3D MOT located 220 mm downstream from the source. The maximum recapture rate of ~10^9 /s is obtained for T=700 K and results in a total of up to 10^10 trapped atoms. The recaptured fraction is estimated to be 30(10)% and limited by beam divergence. The most-probable velocity in the beam (alpha_z) is varied from 18 to 70 m/s by increasing the intensity of a push beam. The source is quite monochromatic with a full-width at half maximum velocity spread of 11 m/s at alpha_z=36 m/s, demonstrating that side-loading completely eliminates beam contamination by hot vapor from the oven. We identify depletion of the low-velocity tail of the oven flux as the limiting loss mechanism. Our approach is suitable for other atomic species.Comment: 13 pages,9 figures, submitted to Phys.Rev.

Metallothionein’s role in PCB126 induced hepatotoxicity and hepatic micronutrient disruption

AbstractPolychlorinated biphenyls (PCBs), industrial chemicals and persistent environmental pollutants, are found in rural and urban settings. Rodent studies have shown that exposure to PCB126, a dioxin-like PCB, causes a significant disruption of hepatic micronutrient homeostasis and an increase in metallothionein (MT), an antioxidant protein and metal carrier. A MT knockout mouse strain was used to assess metallothionein’s role in micronutrient disruption and overall hepatotoxicity. Twenty four 129S male mice (12 wild type (WT) and 12 MT knockout (MTKO)) were placed on a purified diet (AIN-93G) for 3 weeks to achieve hepatic metal equilibrium. Mice were then given a single IP injection of either vehicle or 150μmol/kg PCB126 in vehicle. The animals were sacrificed 2 weeks later and organs processed for analysis. Liver histology, hepatic lipids, gene expression, micronutrient and ROS status were investigated. Liver weights, liver lipids, ROS, and hepatocyte vacuolation were increased with PCB126 exposure along with AhR responsive genes. The MTKO animals had more severe histological changes in the liver and elevated liver lipids than their wild type counterparts. Hepatic and renal metals levels (Cu, Zn, Se and Mn) were mostly reduced by PCB126 treatment. Renal micronutrients were more affected by PCB126 treatment in the MTKO animals. This research suggests that MT may not be the sole/primary cause of the metal disruption caused by PCB126 exposure in mice, but may provide protection against overall hepatotoxicity

Reaction-Diffusion Modelling of Interferon Distribution in Secondary Lymphoid Organs

This paper proposes a quantitative model of the reaction-diffusion type to examine the distribution of interferon-α (IFNα) in a lymph node (LN). The numerical treatment of the model is based on using an original unstructured mesh generation software Ani3D and nonlinear finite volume method for diffusion equations. The study results in suggestion that due to the variations in hydraulic conductivity of various zones of the secondary lymphoid organs the spatial stationary distribution of IFNα is essentially heterogeneous across the organs. Highly protected domains such as sinuses, conduits, co-exist with the regions in which where the stationary concentration of IFNα is lower by about 100-fold. This is the first study where the spatial distribution of soluble immune factors in secondary lymphoid organs is modelled for a realistic three-dimensional geometry