Near-field Testing of the 15-meter Model of the Hoop Column Antenna

The technical results from near-field testing of the 15-meter model of the hoop column antenna at the Martin Marietta Denver Aerospace facility are documented. The antenna consists of a deployable central column and a 15 meter hoop, stiffened by cables into a structure with a high tolerance repeatable surface and offset feed location. The surface has been configured to have four offset parabolic apertures, each about 6 meters in diameter, and is made of gold plated molybdenum wire mesh. Pattern measurements were made with feed systems radiating at frequencies of 7.73, 11.60, 2.27, 2.225, and 4.26 (all in GHz). This report (Volume 1) covers the testing from an overall viewpoint and contains information of generalized interest for testing large antennas. This volume discusses the deployment of the antenna in the Martin Facility and the measurements to determine mechanical stability and trueness of the reflector surface, gives the test program outline, and gives a synopsis of antenna electromagnetic performance. Three techniques for measuring surface mechanical tolerances were used (theodolites, metric cameras, and near-field phase), but only the near-field phase approach is included. The report also includes an error analysis. A detailed listing of the antenna patterns are provided for the 2.225 Ghz feed in Volume 3 of this report, and for all other feeds in Volume 2

Discriminative imaging of maternal and fetal blood flow within the placenta using ultrafast ultrasound

Remerciements à INRA UCEA et CR2iInternational audienceBeing able to map accurately placental blood flow in clinics could have major implications in the diagnosis and follow-up of pregnancy complications such as intrauterine growth restriction (IUGR). Moreover, the impact of such an imaging modality for a better diagnosis of placental dysfunction would require to solve the unsolved problem of discriminating the strongly intricated maternal and fetal vascular networks. However, no current imaging modality allows both to achieve sufficient sensitivity and selectivity to tell these entangled flows apart. Although ultrasound imaging would be the clinical modality of choice for such a problem, conventional Doppler echography both lacks of sensibility to detect and map the placenta microvascularization and a concept to discriminate both entangled flows. In this work, we propose to use an ultrafast Doppler imaging approach both to map with an enhanced sensitivity the small vessels of the placenta (~100 μm) and to assess the variation of the Doppler frequency simultaneously in all pixels of the image within a cardiac cycle. This approach is evaluated in vivo in the placenta of pregnant rabbits: By studying the local flow pulsatility pixel per pixel, it becomes possible to separate maternal and fetal blood in 2D from their pulsatile behavior. Significance Statement: The in vivo ability to image and discriminate maternal and fetal blood flow within the placenta is an unsolved problem which could improve the diagnosis of pregnancy complications such as intrauterine growth restriction or preeclampsia. To date, no imaging modality has both sufficient sensitivity and selectivity to discriminate these intimately entangled flows. We demonstrate that Ultrafast Doppler ultrasound method with a frame rate 100x faster than conventional imaging solves this issue. It permits the mapping of small vessels of the placenta (~100 μm) in 2D with an enhanced sensitivity. By assessing pixel-per-pixel pulsatility within single cardiac cycles, it achieves maternal and fetal blood flow discrimination

Investor-State Dispute Settlement: Is There a Better Alternative?

As the world has transitioned from national; isolated economies with localized issues into a globalized and interconnected economy with cross-border disputes; the law has struggled to keep up. Recent trade negotiations have highlighted the difficulty states face in promoting trade; while also creating a fair; accessible; and equitable forum for producers and consumers with nationalities touching every area of the globe. For several decades; Investor-State Dispute Settlement (ISDS) has been in place to address claims brought by foreign investors against the host states. External improvements have helped support foreign direct investment and the ISDS model of dispute resolution; such as the Convention on the Recognition and Enforcement of Foreign Arbitral Awards. Even with refinements of ISDS; opponents continue to argue that the best days of ISDS have come and gone; contending that the system requires a major overhaul or a new forum all together. The European Union has responded by proposing an alternative multilateral investment court (“Investment Court System”); hoping to address many of the flaws and limitations ISDS faces. If successful; it could be expanded to the globally accepted forum. This Note argues that although the Investment Court System does not resolve all concerns raised against ISDS; it is the best solution proposed thus far. Specifically; this Note demonstrates how the Investor Court System will improve and alter international trade dispute resolution by further promoting fairness; transparency; and cohesiveness in ways ISDS currently does not

Invention Convention Committee Member

Download full tex

ON THE USE OF UNMANNED AERIAL VEHICLES TO RAPIDLY ASSESS MICROHABITATS OF TWO TEXAS LIZARD SPECIES, COPHOSAURUS TEXANUS AND ASPIDOSCELIS GULARIS

We examined the effectiveness of using an unmanned aerial vehicle (UAV) as a tool for the rapid assessment of microhabitat in Texas spotted whiptail (Aspidoscelis gularis) and greater earless lizard (Cophosaurus texanus). We collected microhabitat data from aerial images captured at lizard sightings along gravel roadways on Devils River State Natural Area – Big Satan Unit (DRSNA-BSU) from July through September, 2014. Point locations of lizard sightings were also compared with DRSNA-BSU environmental maps including: soil type, vegetation type, Normalized Difference Vegetation Index (NDVI), elevation, and slope. Multiresponse Permutation Procedures (MRPP) and Permutational Multiple Analysis of Variance (PerMANOVA) analyses indicated that the spatial distributions of the two lizard species were significantly different. Non-metric Multidimensional Scaling (NMDS) analyses revealed that grasslands, low slopes, and soft soils were correlated with the presence of A. gularis while steep slopes, rocky soils, and the xeric plants lechuguilla, sotol, and guajillo were associated with the presence of C. texanus. Our data are consistent with other habitat association analyses administered on these two lizards. UAVs provided a new perspective on the study of microhabitat and we recommend them as a method of rapid habitat assessment. Data collection for one individual lizard in the field could be completed in less than three minutes with the use of our UAV, making the technology an ideal technique for gathering habitat data in a short amount of time

Control of Vocal Production in Budgerigars (Melopsittacus undulatus)

Budgerigars engage in dynamic vocal interactions with conspecifics, learn their vocalizations in a rich social environment, and rely to some extent on auditory feedback to acquire and maintain normal vocal output. However, little is known about the exact role of sensory input and sensory feedback in the control of vocal production in these birds. For example, we know that these birds learn best in a social environment that contains both auditory and visual information, yet we know very little about how this information guides and influences vocal production. Although we suspect that budgerigars rely on auditory feedback for the learning and maintenance of vocal behavior, we do not know whether there are refined, compensatory feedback mechanisms similar to that of humans. Finally, we do not know whether, or to what extent, calls can be modified in structure during learning. This dissertation describes a series of experiments that use more highly controlled and regimented conditions than previous studies with songbirds to investigate the control of vocal production in budgerigars and to provide a more detailed description of some of the mechanisms underlying vocal learning in budgerigars

On the Incorporation of Friction Into a Simultaneously Coupled Time Domain Model of a Rigid Rotor Supported by Air Foil Bearings

Despite decades of research, the dynamics of air foil bearings (AFBs) are not yet fully captured by any model, suggesting that the fundamental mechanisms of the AFB and their relative merits are not yet fully understood. The recent years have seen promising results from nonlinear time domain models, allowing the dynamic pressure– compliance interaction and the unsteady terms of the compressible Reynolds equation to be considered. By including the simple elastic foundation model (SEFM) in a fully coupled simultaneous time integration, the dynamics of a rotor supported by industrial AFBs have previously been modelled by the authors, leading to good agreement with experimental results. In this paper, the authors investigate the substitution of the SEFM for a new foil structure model which is based on directly measurable quantities and includes frictional energy dissipation in the foil structure. An important finding is that the incorporation of a friction model into the global model cannot be reconciled with a simultaneous time solution without the inclusion of the foil inertia. The resulting AFB model allows the effects of friction on AFB performance to be directly examined and leads to the questioning of friction’s role and its significance to the operation of AFBs

The Effect of Sleep and Emotion on Pattern Separation

Prior work on the relationship between sleep and memory suggests that the sleep state is an optimal time for memory consolidation to occur. During slow wave sleep, newly encoded information in the hippocampus is repeatedly activated, driven by slow oscillations that originate in the neocortex. This process that occurs during slow wave sleep facilitates the long-term storage of memories. A widely accepted view of emotion and sleep is that emotional memories are preferentially consolidated during sleep so that they are easily accessible for retrieval, whereas neutral memories tend to be less accessible. However, recent meta-analyses of sleep, emotion, and memory have suggested that this effect may not be as robust as we once thought. To address this issue, the current study investigated the influence of sleep on the consolidation of emotional and neutral memories in a pattern separation task. The results showed no difference between the sleep and wake group on measures of pattern separation or item recognition and no preferential consolidation of emotional images over neutral images. These findings contradict prior literature, but raise questions about the role of sleep in memory consolidation, and more specifically, emotional memory consolidation