Fast High Resolution Echelle Spectroscopy Of A Laboratory Plasma

An echelle diffraction grating and a multianode photomultiplier tube are paired to construct a high resolution (R=lambda/delta lambda approximate to 2.5x10(4)) spectrograph with fast time response for use from the UV through the visible. This instrument has analyzed the line shape of C III impurity ion emission at 229.687 nm over the lifetime (approximate to 100 mu s) of the hydrogen plasmas produced at SSX. The ion temperature and line of sight average velocity are inferred from the observed thermal broadening and Doppler shift of the line. The time resolution of these measurements is about 1 mu s, sufficient to observe the fastest magnetohydrodynamic activity

The atomic structure and chemistry of Fe-rich steps on antiphase boundaries in Ti-doped Bi_0.9Nd_0.15FeO3

Stepped antiphase boundaries are frequently observed in Ti-doped Bi<sub>0.85</sub>Nd<sub>0.15</sub>FeO<sub>3</sub>, related to the novel planar antiphase boundaries reported recently. The atomic structure and chemistry of these steps are determined by a combination of high angle annular dark field and bright field scanning transmission electron microscopy imaging, together with electron energy loss spectroscopy. The core of these steps is found to consist of 4 edge-sharing FeO<sub>6</sub> octahedra. The structure is confirmed by image simulations using a frozen phonon multislice approach. The steps are also found to be negatively charged and, like the planar boundaries studied previously, result in polarisation of the surrounding perovskite matrix

Impact hazard protection efficiency by a small kinetic impactor

In this paper the ability of a small kinetic impactor spacecraft to mitigate an Earth-threatening asteroid is assessed by means of a novel measure of efficiency. This measure estimates the probability of a space system to deflect a single randomly-generated Earth-impacting object to a safe distance from the Earth. This represents a measure of efficiency that is not biased by the orbital parameters of a test-case object. A vast number of virtual Earth-impacting scenarios are investigated by homogenously distributing in orbital space a grid of 17,518 Earth impacting trajectories. The relative frequency of each trajectory is estimated by means Opik’s theory and Bottke’s near Earth objects model. A design of the entire mitigation mission is performed and the largest deflected asteroid computed for each impacting trajectory. The minimum detectable asteroid can also be estimated by an asteroid survey model. The results show that current technology would likely suffice against discovered airburst and local damage threats, whereas larger space systems would be necessary to reliably tackle impact hazard from larger threats. For example, it is shown that only 1,000 kg kinetic impactor would suffice to mitigate the impact threat of 27.1% of objects posing similar threat than that posed by Apophis

Involuntary Servitude: The Current Enforcement of Employee Covenants Not to Compete – A Proposal for Reform

A covenant not to compete is a contractual restriction upon an individual\u27s ability to compete with another person or entity following the termination of some transaction or relationship between the two. Because of the increasing emphasis in the American economy on technically skilled employees and service oriented businesses, the covenant not to compete has become a standard addition to employment contracts. Moreover, the number of litigated and reported cases may represent only a small percentage of the actual number of employment restrictions currently in force. Regardless of their validity and enforceability, covenants not to compete chill the free movement of employees and eliminate competition among actual and potential employers. Because of both these effects and the existence of many unchallenged covenants of questionable validity, the judicial system must clearly define the legal parameters of the enforceability of such covenants. Traditionally, scholars in this area have generally been content to organize the voluminous case law available and describe the patterns of legal analysis contained therein. This Article instead suggests a unifying theory for consistently resolving all litigation of covenants not to compete. This theory focuses on the employer\u27s protectable interest and limits postassociational restraints to the extent of this interest. This Article proposes that the appropriate sources of both the definition of protectable interest and the limitation on injunctive relief are those agency and unfair competition doctrines that justify postassociational restraints in the absence of contractual restrictions. Under this approach, the terms of any agreement will generally be viewed as superfluous. This Article concludes that the covenant not to compete and related contract law rules should, in most cases, be given no effect

Involuntary Servitude: The Current Enforcement of Employee Covenants Not to Compete – A Proposal for Reform

A covenant not to compete is a contractual restriction upon an individual\u27s ability to compete with another person or entity following the termination of some transaction or relationship between the two. Because of the increasing emphasis in the American economy on technically skilled employees and service oriented businesses, the covenant not to compete has become a standard addition to employment contracts. Moreover, the number of litigated and reported cases may represent only a small percentage of the actual number of employment restrictions currently in force. Regardless of their validity and enforceability, covenants not to compete chill the free movement of employees and eliminate competition among actual and potential employers. Because of both these effects and the existence of many unchallenged covenants of questionable validity, the judicial system must clearly define the legal parameters of the enforceability of such covenants. Traditionally, scholars in this area have generally been content to organize the voluminous case law available and describe the patterns of legal analysis contained therein. This Article instead suggests a unifying theory for consistently resolving all litigation of covenants not to compete. This theory focuses on the employer\u27s protectable interest and limits postassociational restraints to the extent of this interest. This Article proposes that the appropriate sources of both the definition of protectable interest and the limitation on injunctive relief are those agency and unfair competition doctrines that justify postassociational restraints in the absence of contractual restrictions. Under this approach, the terms of any agreement will generally be viewed as superfluous. This Article concludes that the covenant not to compete and related contract law rules should, in most cases, be given no effect

Torpor Inducing Transfer Habitat for Human Stasis to Mars

SpaceWorks Enterprises, Inc. has performed an initial evaluation of an advanced habitat system designed to transport crews between the Earth and Mars. This new and innovative habitat design is capable of placing the crew in an inactive, torpor state for the duration of the in-space mission segments. This substantially reduces the mass and size of the habitat, which ultimately leads to significant reductions in the overall architecture size.Our approach for achieving this is based on extending the current and evolving medical practice of Therapeutic Hypothermia (TH) a proven and effective treatment for various traumatic injuries. TH is a medical treatment that lowers a patient's body temperature by just 5 to 10 degrees Fahrenheit causing their metabolism to reduce significantly and the body to enter an unconscious state. This method avoids the intractable challenges often associated with cell metabolic cessation through cryogenic freezing and other highly speculative approaches.TH is a proven treatment for traumatic injuries; however it has not been applied for non-critical care purposes due to current lack of purpose (i.e. no practical need). The opportunity exists to use TH in this capacity to enable and enhance our human spaceflight capability. With this concept, we have the potential to simultaneously solve multiple exploration challenges

Sintering of titanium with yttrium oxide additions for the scavenging of chlorine impurities

Chloride impurities in titanium powders are extremely difficult to remove and present a long-standing problem in titanium powder metallurgy. We show that the detrimental effects of chlorides on the sintering of titanium can be mitigated with trace additions of yttrium oxide, which has a high affinity for the normally volatile species and forms highly stable oxychloride reaction products. Compacts that would otherwise exhibit gross swelling and excessive porosity due to chloride impurities can be now sintered to near full density by liquid phase sintering. The potency of yttrium oxide additions is observable at levels as low as 500 ppm. The scavenging of chlorine by YO appears to be independent of alloy composition and sintering regime. It is effective when used with high-chloride powders such as Kroll sponge fines but ineffective when used with powders containing NaCl impurities or during solid-state sintering. The identification of highly potent chlorine scavengers may enable the future development of chloride-tolerant powder metallurgy (PM) alloys aimed at utilizing low-cost, high-chloride powder feedstocks

Three-Dimensional Magnetohydrodynamics Simulations Of Counter-Helicity Spheromak Merging In The Swarthmore Spheromak Experiment

Recent counter-helicity spheromak merging experiments in the Swarthmore Spheromak Experiment (SSX) have produced a novel compact torus (CT) with unusual features. These include a persistent antisymmetric toroidal magnetic field profile and a slow, nonlinear emergence of the n = 1 tilt mode. Experimental measurements are inconclusive as to whether this unique CT is a fully merged field-reversed configuration (FRC) with strong toroidal field or a partially merged doublet CT configuration with both spheromak- and FRC-like characteristics. In this paper, the SSX merging process is studied in detail using three-dimensional resistive MHD simulations from the Hybrid Magnetohydrodynamics (HYM) code. These simulations show that merging plasmas in the SSX parameter regime only partially reconnect, leaving behind a doublet CT rather than an FRC. Through direct comparisons, we show that the magnetic structure in the simulations is highly consistent with the SSX experimental observations. We also find that the n = 1 tilt mode begins as a fast growing linear mode that evolves into a slower-growing nonlinear mode before being detected experimentally. A simulation parameter scan over resistivity, viscosity, and line-tying shows that these parameters can strongly affect the behavior of both the merging process and the tilt mode. In fact, merging in certain parameter regimes is found to produce a toroidal-field-free FRC rather than a doublet CT. (C) 2011 American Institute of Physics. [doi:10.1063/1.3660533