Pre-design study for a modern four-bladed rotor for the Rotor System Research Aircraft (RSRA)

Various candidate rotor systems were compared in an effort to select a modern four-bladed rotor for the RSRA. The YAH-64 rotor system was chosen as the candidate rotor system for further development for the RSRA. The process used to select the rotor system, studies conducted to mate the rotor with the RSRA and provide parametric variability, and the development plan which would be used to implement these studies are presented. Drawings are included

The Subcolonization and Buildup of \u3ci\u3eTetrastichus Julis,\u3c/i\u3e (Hymenoptera: Eulophidae) a Larval Parasitoid of the Cereal Leaf Beetle, (Coleoptera: Chrysomelidae) in the Lower Peninsula of Michigan

Following initial establishment of the parasitoid, Tetrastichus julis (Walker), at a carefully managed field nursery, releases of parasitized Oulema melanopus larvae were made by Michigan county agents at preselected sites throughout the lower peninsula during 1970-74. A follow-up recovery program during 1971-75 revealed continued dispersion and population increase for T. julis. An independent census verified the increasing rates of parasitism

Electronic Properties of Strained Si/Ge Core-Shell Nanowires

We investigated the electronic properties of strained Si/Ge core-shell nanowires along the [110] direction using first principles calculations based on density-functional theory. The diameter of the studied core-shell wire is up to 5 nm. We found the band gap of the core-shell wire is smaller than that of both pure Si and Ge wires with the same diameter. This reduced band gap is ascribed to the intrinsic strain between Ge and Si layers, which partially counters the quantum confinement effect. The external strain is further applied to the nanowires for tuning the band structure and band gap. By applying sufficient tensile strain, we found the band gap of Si-core/Ge-shell nanowire with diameter larger than ~3 nm experiences a transition from direct to indirect gap.Comment: 4 figure

Toward a Bias Corrected Currency Equivalent Index

Measuring the economic stock of money, defined to be the present value of current and future monetary service flows, is a difficult asset pricing problem, because most monetary assets yield interest. Thus, an interest yielding monetary asset is a joint product: a durable good providing a monetary service flow and a financial asset yielding a return. The currency equivalent index provides an elegant solution, but it does so by making strong assumptions about expectations of future monetary service flows. These assumptions cause the currency equivalent index to exhibit significant downward bias. In this paper, we propose an extension to the currency equivalent index that will correct for a significant amount of this bias.Currency equivalent index, monetary aggregation, money stock

Classification and reduction of pilot error

Human error is a primary or contributing factor in about two-thirds of commercial aviation accidents worldwide. With the ultimate goal of reducing pilot error accidents, this contract effort is aimed at understanding the factors underlying error events and reducing the probability of certain types of errors by modifying underlying factors such as flight deck design and procedures. A review of the literature relevant to error classification was conducted. Classification includes categorizing types of errors, the information processing mechanisms and factors underlying them, and identifying factor-mechanism-error relationships. The classification scheme developed by Jens Rasmussen was adopted because it provided a comprehensive yet basic error classification shell or structure that could easily accommodate addition of details on domain-specific factors. For these purposes, factors specific to the aviation environment were incorporated. Hypotheses concerning the relationship of a small number of underlying factors, information processing mechanisms, and error types types identified in the classification scheme were formulated. ASRS data were reviewed and a simulation experiment was performed to evaluate and quantify the hypotheses

In Pursuit of Sport Sustainability: Fund-Raising and the NCAA Division I Track and Field Core Product

National Collegiate Athletic Association (NCAA) Division I track and field programs have been a target of elimination in recent decades (Irick, 2011) as funds are often allocated to sports that provide the largest perceived potential return on investment (Marburger & Hogshead-Makar, 2003). Building on research that documents the influential role coaches can play in sport sustainability efforts (Cooper, 2012; Weight, 2010; Weight & Cooper, 2011), this study examines fund raising and fortification strategies of 111 Division I coaches through survey methodology. Important fund raising strategies emerged including communication with donors, maintaining an up-to-date contact database, and providing thank-you notes and/ or gifts to donors. Fortification strategies to enhance demand for collegiate track and field included decreasing the length of competitions and scoring regular season meets

Spectral properties of a narrow-band Anderson model

We consider single-particle spectra of a symmetric narrow-band Anderson impurity model, where the host bandwidth $D$ is small compared to the hybridization strength $\Delta_{0}$. Simple 2nd order perturbation theory (2PT) in $U$ is found to produce a rich spectral structure, that leads to rather good agreement with extant Lanczos results and offers a transparent picture of the underlying physics. It also leads naturally to two distinct regimes of spectral behaviour, $\Delta_{0}Z/D\gg 1$ and $\ll 1$ (with $Z$ the quasi-particle weight), whose existence and essential characteristics are discussed and shown to be independent of 2PT itself. The self-energy $\Sigma_{i\omega}$ is also examined beyond the confines of PT. It is argued that on frequency scales of order $\omega\sim\sqrt{Delta_{0}D}$, the self-energy in {\em strong} coupling is given precisely by the 2PT result, and we point out that the resultant poles in $\Sigma_{i\omega}$ connect continuously to that characteristic of the atomic limit. This in turn offers a natural rationale for the known inability of the skeleton expansion to capture such behaviour, and points to the intrinsic dangers of partial infinite-order summations that are based on PT in $U$.Comment: 10 pages, 2 Postscript figures, uses RevTex 3.1; accepted for publication in Phys. Rev. B1

A trans-diagnostic perspective on obsessive-compulsive disorder

© Cambridge University Press 2017. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.Progress in understanding the underlying neurobiology of obsessive-compulsive disorder (OCD) has stalled in part because of the considerable problem of heterogeneity within this diagnostic category, and homogeneity across other putatively discrete, diagnostic categories. As psychiatry begins to recognize the shortcomings of a purely symptom-based psychiatric nosology, new data-driven approaches have begun to be utilized with the goal of solving these problems: specifically, identifying trans-diagnostic aspects of clinical phenomenology based on their association with neurobiological processes. In this review, we describe key methodological approaches to understanding OCD from this perspective and highlight the candidate traits that have already been identified as a result of these early endeavours. We discuss how important inferences can be made from pre-existing case-control studies as well as showcasing newer methods that rely on large general population datasets to refine and validate psychiatric phenotypes. As exemplars, we take 'compulsivity' and 'anxiety', putatively trans-diagnostic symptom dimensions that are linked to well-defined neurobiological mechanisms, goal-directed learning and error-related negativity, respectively. We argue that the identification of biologically valid, more homogeneous, dimensions such as these provides renewed optimism for identifying reliable genetic contributions to OCD and other disorders, improving animal models and critically, provides a path towards a future of more targeted psychiatric treatments.Peer reviewedFinal Published versio

Field-dependent dynamics of the Anderson impurity model

Single-particle dynamics of the Anderson impurity model in the presence of a magnetic field $H$ are considered, using a recently developed local moment approach that encompasses all energy scales, field and interaction strengths. For strong coupling in particular, the Kondo scaling regime is recovered. Here the frequency ($\omega/\omega_{\rm K}$) and field ($H/\omega_{\rm K}$) dependence of the resultant universal scaling spectrum is obtained in large part analytically, and the field-induced destruction of the Kondo resonance investigated. The scaling spectrum is found to exhibit the slow logarithmic tails recently shown to dominate the zero-field scaling spectrum. At the opposite extreme of the Fermi level, it gives asymptotically exact agreement with results for statics known from the Bethe ansatz. Good agreement is also found with the frequency and field-dependence of recent numerical renormalization group calculations. Differential conductance experiments on quantum dots in the presence of a magnetic field are likewise considered; and appear to be well accounted for by the theory. Some new exact results for the problem are also established

Case History Illustrating the Challenges of Foundation Design and Construction in Karst Terrain

This paper discusses the challenges associated with design and construction of foundation systems for a Corporate Campus located in Chester County, Pennsylvania that is underlain by Karst terrain. A comprehensive subsurface investigation was implemented to develop adequate foundation systems and related site work precautions. Because there was evidence of sinkhole activity prior to any construction work, and the subsoils revealed some variability from a consistency/density standpoint, the selected foundation system design included a combination of soil improvement using compaction grouting for shallow foundations and deep drilled-pier foundations. After construction activities began, several occurrences of solution activity were documented and repaired. During construction of drilled-pier foundations at one of the structure locations, a significant number of voids and discontinuities in the rock were encountered. The impact of these discontinuities and voids was dramatic to the effort and time necessary to complete the drilled pier foundation construction for this structure. After careful consideration of potential cost and schedule impacts, the foundation design for remaining structures was modified to eliminate the use of drilled piers and incorporated only compaction grouting for support of shallow foundation systems. Interaction of the Geotechnical Engineer, Construction Manager, Owner, and Contractor began early in the construction process and this interaction became critical to the project success as work proceeded on this project