Preferences of US and EU Undergraduates for Cloning

cloning, consumer preferences, Agribusiness, Agricultural and Food Policy, Food Consumption/Nutrition/Food Safety,

The divergence characteristics of constrained-sheath optics systems for use with 5-eV atomic oxygen sources

The potential usefulness of the constrained sheath optics concept as a means of controlling the divergence of low energy, high current density ion beams is examined numerically and experimentally. Numerical results demonstrate that some control of the divergence of typical ion beamlets can be achieved at perveance levels of interest by contouring the surface of the constrained sheath properly. Experimental results demonstrate that a sheath can be constrained by a wire mesh attached to the screen plate of the ion optics system. The numerically predicted beamlet divergence characteristics are shown to depart from those measured experimentally, and additional numerical analysis is used to demonstrate that this departure is probably due to distortions of the sheath caused by the fact that it attempts to conform to the individual wires that make up the sheath constraining mesh. The concept is considered potentially useful in controlling the divergence of ion beamlets in applications where low divergence, low energy, high current density beamlets are being sought, but more work is required to demonstrate this for net beam ion energies as low as 5 eV

Modular vector fields attached to Dwork family: sl2(C)\mathfrak{sl}_2(\mathbb{C}) Lie algebra

We introduce an algebraic group $\sf G$ that acts from right on the moduli space $\textsf{T}$ of Calabi-Yau $n$-folds arising from Dwork family enhanced with differential forms, and describe its Lie algebra ${\rm Lie}({\sf G})$. We observe that ${\rm Lie}({\sf G})$ together with a modular vector field ${\sf R}$ on $\textsf{T}$ generates another Lie algebra $\mathfrak{G}$, called AMSY-Lie algebra, such that $\dim \mathfrak{G}=\dim {\sf T}$. We find $\mathfrak{sl}_2(\mathbb{C})$ as a Lie subalgebra of $\mathfrak{G}$ that contains $\sf R$.Comment: 20 page

Chameleon effect and the Pioneer anomaly

The possibility that the apparent anomalous acceleration of the Pioneer 10 and 11 spacecraft may be due, at least in part, to a chameleon field effect is examined. A small spacecraft, with no thin shell, can have a more pronounced anomalous acceleration than a large compact body, such as a planet, having a thin shell. The chameleon effect seems to present a natural way to explain the differences seen in deviations from pure Newtonian gravity for a spacecraft and for a planet, and appears to be compatible with the basic features of the Pioneer anomaly, including the appearance of a jerk term. However, estimates of the size of the chameleon effect indicate that its contribution to the anomalous acceleration is negligible. We conclude that any inverse-square component in the anomalous acceleration is more likely caused by an unmodelled reaction force from solar-radiation pressure, rather than a chameleon field effect.Comment: 16 pages; to appear in Phys.Rev.

Solubility of carbon in molten copper-manganese and copper-nickel alloys

Thesis (M.S.) Massachusetts Institute of Technology. Dept. of Metallurgy, 1946.Bibliography: leaves 30-31.by John R. Anderson.M.S

Flight Test and Handling Qualities Analysis of a Longitudinal Flight Control System Using Multiobjective Techniques

This thesis addresses the application of optimal, multiobjective control theory control theory to flight control design for the approach and landing phase of flight. Five flight control systems were designed using classical, H2, H infinity, and Mixed H2/H infinity methods. The MATLAB™ MUTOOLS™ and AFIT MXTOOLS toolboxes were used to produce the optimal, multiobjective designs. These designs were implemented for flight test on the Calspan VSS I Learjet, simulating the unstable longitudinal dynamics of an F-16 type aircraft. A limited handling qualities investigation was performed. Model following was used in the design phase to meet handling qualities specifications. The designs were successfully implemented and verified on the Calspan Learjet prior to flight test. An unmodeled aircraft mode was discovered just prior to flight test that made three of the designs slightly unstable. However, all of the designs achieved Level II or better Cooper-Harper handling qualities ratings for the landing tasks performed illustrating that the optimal multiobjective methods used can give acceptable or better handling qualities

Internal fluid mechanics research on supercomputers for aerospace propulsion systems

The Internal Fluid Mechanics Division of the NASA Lewis Research Center is combining the key elements of computational fluid dynamics, aerothermodynamic experiments, and advanced computational technology to bring internal computational fluid mechanics (ICFM) to a state of practical application for aerospace propulsion systems. The strategies used to achieve this goal are to: (1) pursue an understanding of flow physics, surface heat transfer, and combustion via analysis and fundamental experiments, (2) incorporate improved understanding of these phenomena into verified 3-D CFD codes, and (3) utilize state-of-the-art computational technology to enhance experimental and CFD research. Presented is an overview of the ICFM program in high-speed propulsion, including work in inlets, turbomachinery, and chemical reacting flows. Ongoing efforts to integrate new computer technologies, such as parallel computing and artificial intelligence, into high-speed aeropropulsion research are described