NiO Exchange Bias Layers Grown by Direct Ion Beam Sputtering of a Nickel Oxide Target

A new process for fabricating NiO exchange bias layers has been developed. The process involves the direct ion beam sputtering (IBS) of a NiO target. The process is simpler than other deposition techniques for producing NiO buffer layers, and facilitates the deposition of an entire spin-valve layered structure using IBS without breaking vacuum. The layer thickness and temperature dependence of the exchange field for NiO/NiFe films produced using IBS are presented and are similar to those reported for similar films deposited using reactive magnetron sputtering. The magnetic properties of highly textured exchange couples deposited on single crystal substrates are compared to those of simultaneously deposited polycrystalline films, and both show comparable exchange fields. These results are compared to current theories describing the exchange coupling at the NiO/NiFe interface.Comment: 9 pages, Latex 2.09, 3 postscript figures. You can also this manuscript at http://www.wsrcc.com/alison/fixed-nio/manuscript.html To be published in _IEEE Trans. Magn._, Nov. 199

Computational complexity of μ calculation

The structured singular value μ measures the robustness of uncertain systems. Numerous researchers over the last decade have worked on developing efficient methods for computing μ. This paper considers the complexity of calculating μ with general mixed real/complex uncertainty in the framework of combinatorial complexity theory. In particular, it is proved that the μ recognition problem with either pure real or mixed real/complex uncertainty is NP-hard. This strongly suggests that it is futile to pursue exact methods for calculating μ of general systems with pure real or mixed uncertainty for other than small problems

Training Levels and Methodologies for Glass Cockpit Training in Collegiate Aviation

Modern commercial aircraft use extremely complex and sophisticated flight instrumentation systems that present training concerns for the aviation industry and collegiate aviation programs. The authors sampled 42 four-year collegiate flight-training programs to determine their current program emphasis on glass cockpit training and plans for curriculum enhancements in that area. Although nearly fifty percent of sampled program administrators believe instruction in flight automation is critical to the success of their graduates, most cite cost of materials and competing curriculum priorities as reasons to defer such instruction to future employers. The authors suggest that program enhancements are within the reach of modern college aviation programs and offer suggestions for three different levels of glass cockpit training

A candidate LiBH4 for hydrogen storage: Crystal structures and reaction mechanisms of intermediate phases

First-principles calculation and x-ray diffraction simulation methods have been used to explore crystal structures and reaction mechanisms of the intermediate phases involved in dehydriding of LiBH4. LiBH4 was found to dehydride via two sequential steps: first dehydriding through LiBH, followed by the dehydriding of LiBH through LiB. The first step, which releases 13.1 wt. % hydrogen, was calculated to have an activation barrier of 2.33 eV per formula unit and was endothermic by 1.28 eV per formula unit, while the second step was endothermic by 0.23 eV per formula unit. On the other hand, if LiBH4 and LiBH each donated one electron, possibly to the catalyst doped on their surfaces, it was found that the barrier for the first step was reduced to 1.50 eV. This implies that the development of the catalyst to induce charge migration from the bulk to the surface is essential to make LiBH4 usable as a hydrogen storage material in a moderate temperature range, which is also important to stabilize the low-temperature structure of Pnma (no. 62) LiBH on dehydrogenation. Consequently, the high 13.1 wt. % hydrogen available from the dehydriding of LiBH4 and LiBH and their phase stability on Pnma when specific catalysts were used suggest that LiBH4 has good potential to be developed as the hydrogen storage medium capable of releasing the Department of Energy target of 6.5 wt. % for a hydrogen fuel cell car in a moderate temperature range

Adapting Baumol’s inventory theoretic to landed cost decisions

Major U.S. corporations have been importers for over 200 years. A significant impetus for “offshoring” has been reducing costs—usually labor costs. Often, other costs were overlooked. There has been a growing disenchantment with sourcing goods overseas, especially when there may be domestic alternatives as other costs begin to dominate. Baumol and Vinod’s Inventory Theoretic model was useful in adding transportation considerations. However, Baumol leaves out several important costs that unless considered in offshoring decisions can lead to suboptimal solutions. This paper extends that model, providing a prescriptive model that could be operationalized by firms to evaluate offshore sourcing decisions

Impact of Glass Cockpit Experience on Manual Flight Skills

Modern aircraft employ a wide variety of advanced flight instrument systems that have been designed to reduce pilot workload and promote safe, efficient flight operations. Research to date on advanced flight instrumentation has primarily focused on mode confusion or pilot misinterpretation of system information. A few studies have also identified pilot concern with a reduction in manual flight skills as a result of regular operation in automated modes. This paper addresses that concern in an attempt to identify factors useful to flight curriculum development. Study participants included 110 experienced airline, corporate, and military pilots who were surveyed before and after a training session in a transport category flight training device with round dial instrumentation. An experienced instructor rated participant flight skills during the simulator activity. Study findings suggest that pilots who are more likely to use automated modes of modern glass cockpit aircraft have a less effective crosscheck and reduced manual flight skills. Issues related to advanced flight deck operations and training are discussed

Towards Operationalizing Driver Distraction

Driver distraction has been the subject of much research interest and scientific inquiry. Operationalizing driver distraction is a complex task—one that is necessary for advancing both science and public policy in this domain. While many operational definitions can be gathered from the literature, gaps are common. In order to fill such gaps, 21 experts reviewed 55 driver distraction definitions in the literature. Aided by the results of a pre-workshop questionnaire the experts narrowed these definitions. The Regan et al. (2011) definition of driver distraction was agreed to at a workshop. Subsidiary terms related to this definition were defined to improve clarity and applicability of the definition. It is hoped that a consistent and agreed definition of driver distraction and its associated terms will advance scientific progress in understanding and measuring driver distraction