Employing pre-stress to generate finite cloaks for antiplane elastic waves

It is shown that nonlinear elastic pre-stress of neo-Hookean hyperelastic materials can be used as a mechanism to generate finite cloaks and thus render objects near-invisible to incoming antiplane elastic waves. This approach appears to negate the requirement for special cloaking metamaterials with inhomogeneous and anisotropic material properties in this case. These properties are induced naturally by virtue of the pre-stress. This appears to provide a mechanism for broadband cloaking since dispersive effects due to metamaterial microstructure will not arise.Comment: 4 pages, 2 figure

Stabilized lanthanum sulphur compounds

Lanthanum sulfide is maintained in the stable cubic phase form over a temperature range of from 500 C to 1500 C by adding to it small amounts of calcium, barium, or strontium. This compound is an excellent thermoelectric material

Ferroelectric characterization and growth optimization of thermally evaporated vinylidene fluoride thin films

Organic thin films have numerous advantages over inorganics in device processing and price. The large polarization of the organic ferroelectric oligomer vinylidene fluoride (VDF) could prove useful for both device applications and the investigation of fundamental physical phenomena. A VDF oligomer thin film vacuum deposition process, such as thermal evaporation, preserves film and interface cleanliness, but is challenging, with successful deposition occurring only within a narrow parameter space. We report on the optimal deposition parameters for VDF oligomer thin films, refining the parameter space for successful deposition, resulting in a high yield of robust ferroelectric films. In particular, we investigate the influence of deposition parameters on surface roughness, and the role that roughness plays in sample yield. The reliable production of ferroelectric films allowed us to perform detailed measurements of previously unreported properties, including the Curie temperature, the temperature and thickness dependence of the coercive field, the melting temperature, and the index of refraction. The ability to successfully grow robust, switchable, well-characterized films makes VDF oligomer a viable candidate in the field of organic ferroelectrics

Examining Combat Effectiveness in Asymmetric Engagements with Balanced Forces Using the Information Age Combat Model

With advances in networked communications, the capabilities of command and control (C2) have come to play an increasingly larger role in battlefield success. Within the past two decades a new military strategy has evolved, known as Network-Centric Operations (NCO), which puts information superiority on the frontline. Moreover, the information advantage that is gained through information superiority is translated into a tactical war-fighting advantage. A research gap has been identified in the investigation of networked combat force configurations in the realm of asymmetric engagements. Specifically, the research question is, how should an information age combat force be networked in order to increase its combat effectiveness in asymmetric engagements with balanced forces? The objective of this research is to identify which performance metrics are best suited in measuring combat effectiveness in the situations of asymmetric engagements with balanced force sizes. In order to reach conclusions on the research objective, a series of experiments have been conducted using a discrete-event simulation based on the Information Age Combat Model (IACM). The experiments investigate all of the possible engagements for balanced configurations in the format of X-Y-X, ranging from 3 ≤ X ≤ 10, and 3 ≤ Y ≤ X, where X represents the number of sensors and influencers, and Y represents the number of deciders in the network. A total of 1,457,801 unique combat engagement simulations were conducted for data collection. The exact combat network configurations and percentage of wins for both sides were collected for use in the data analysis. Several computer programs were written in order to calculate the various performance metrics associated with each combat configuration. These data, in addition to the win percentages, are used in order to conduct both linear and nonlinear regression models, so that the value of the metrics may be evaluated as combat network performance indicators. Results indicate that the actual size of the network is a greater predictor for combat performance than any of the metrics calculated from the network configurations. However, it has been determined that network configuration does still play a vital role in combat performance in the case of asymmetric engagements with balanced forces. Moreover, results show that it is possible to configure a network in order to increase its chances of winning in an asymmetric engagement against a larger force size

Expression in the human brain of retinoic acid induced 1, a protein associated with neurobehavioural disorders

Acknowledgements Funding was provided by the Wellcome Trust and Tenovus Scotland. Prof Fragoso is the recipient of a Post Doctoral Science without Borders grant from the Brazilian National Council for Scientific and Technological Development (CNPq, 37450/2012- 7). We also thank Aberdeen Proteomics for assistance with the western blots as well as the Microscopy and Histology Core Facility at the University of Aberdeen for confocal microscopy.Peer reviewedPublisher PD

An evaluation of the Goddard Space Flight Center Library

The character and degree of coincidence between the current and future missions, programs, and projects of the Goddard Space Flight Center and the current and future collection, services, and facilities of its library were determined from structured interviews and discussions with various classes of facility personnel. In addition to the tabulation and interpretation of the data from the structured interview survey, five types of statistical analyses were performed to corroborate (or contradict) the survey results and to produce useful information not readily attainable through survey material. Conclusions reached regarding compatability between needs and holdings, services and buildings, library hours of operation, methods of early detection and anticipation of changing holdings requirements, and the impact of near future programs are presented along with a list of statistics needing collection, organization, and interpretation on a continuing or longitudinal basis

Standard methods for creating digital skeletal models using structure-from-motion photogrammetry.

OBJECTIVES: This article assesses best practices for producing 3D digital cranial models through structure-from-motion (SfM) photogrammetry, and whether the metric accuracy and overall presentation of photogrammetric models are comparable to physical crania. It is intended to present a user-friendly standard method of creating accurate digital skeletal models using Agisoft PhotoScan. MATERIALS AND METHODS: Approximately 200 photographs were taken of three different crania, and were separated into series consisting of 50, 75, 100, 150, and approximately 200 photos. Forty-five cranial models were created using different photo series and a variety of PhotoScan settings. These models were assessed based on defined qualitative criteria, and model measurement estimates were compared with physical skeletal measurements using Bland-Altman plots. RESULTS: The majority of all models (37/45) produced measurement estimates with mean differences of 2 mm or less regardless of PhotoScan settings, and therefore demonstrated high levels of agreement with the physical measurements. Models created with 150 photographs and on "high" PhotoScan settings scored the highest in terms of qualitative appearance in the shortest amount of time. DISCUSSION: In PhotoScan, it is recommended to create cranial models using 150 photographs and "high" settings; this produces digital cranial models that are comparable to physical crania in both appearance and proportion. SfM photogrammetry is a convenient, noninvasive, and rapid 3D modeling tool that can be used in almost any setting to produce digital models, and following the guidelines established here will ensure that these models are metrically accurate