Gradient Photonic Materials Based on One‐Dimensional Polymer Photonic Crystals

In nature, animals such as chameleons are well‐known for the complex color patterns of their skin and the ability to adapt and change the color by manipulating sophisticated photonic crystal systems. Artificial gradient photonic materials are inspired by these color patterns. A concept for the preparation of such materials and their function as tunable mechanochromic materials is presented in this work. The system consists of a 1D polymer photonic crystal on a centimeter scale on top of an elastic poly(dimethylsiloxane) substrate with a gradient in stiffness. In the unstrained state, this system reveals a uniform red reflectance over the entire sample. Upon deformation, a gradient in local strain of the substrate is formed and transferred to the photonic crystal. Depending on the magnitude of this local strain, the thickness of the photonic crystal decreases continuously, resulting in a position‐dependent blue shift of the reflectance peak and hence the color in a rainbow‐like fashion. Using more sophisticated hard‐soft‐hard‐soft‐hard gradient elastomers enables the realization of stripe‐like reflectance patterns. Thus, this approach allows for the tunable formation of reflectance gradients and complex reflectance patterns. Envisioned applications are in the field of mechanochromic sensors, telemedicine, smart materials, and metamaterials

Simulation of seismic events induced by CO2 injection at In Salah, Algeria

Date of Acceptance: 18/06/2015 Acknowledgments The authors would like to thank the operators of the In Salah JV and JIP, BP, Statoil and Sonatrach, for providing the data shown in this paper, and for giving permission to publish. Midland Valley Exploration are thanked for the use of their Move software for geomechanical restoration. JPV is a Natural Environment Research Council (NERC) Early Career Research Fellow (Grant NE/I021497/1) and ALS is funded by a NERC Partnership Research Grant (Grant NE/I010904).Peer reviewedPublisher PD

Numerical modeling of larval settlement in turbulent bottom boundary layers

A time-dependent model of a tidal or wave bottom boundary layer has been developed to quantitatively evaluate the relative influences of vertical advection, turbulent mixing and shear, and near-bed behavior on settlement of planktonic larvae of benthic animals. The settlement behavior of larvae is modeled with a simple flux condition at the bed. This allows full time dependence to be included when determining settlement rates. For tidal oscillations, the model predicts that most settlement will occur at and near periods of slack water, whereas comparatively little settlement will occur during periods of stronger flow. In contrast, there should be little temporal variability in settlement rates associated with short-period wind waves. If larvae exhibit a relatively weak propensity to settle, then the settlement flux is small compared to the advective/turbulent flux of larvae supplied from higher in the water column to regions near the bed. In this case, a description of probability of settlement and a quasi-steady state suspension model fully describe the system. In contrast, when larvae exhibit a high settlement propensity, then the settlement flux is potentially larger than the advective/turbulent flux and the system is controlled by the hydrodynamic supply of larvae to the near-bed region. In this case, net settlement is governed primarily by larval fall velocity (a composite of gravitational sinking plus swimming) and turbulent shear stress. The ecological systems which are controlled by animal behavior or by physical processes may thus be identified by estimates of relatively simple parameters describing these fluxes

3D Radiative Transfer with PHOENIX

Using the methods of general relativity Lindquist derived the radiative transfer equation that is correct to all orders in v/c. Mihalas developed a method of solution for the important case of monotonic velocity fields with spherically symmetry. We have developed the generalized atmosphere code PHOENIX, which in 1-D has used the framework of Mihalas to solve the radiative transfer equation (RTE) in 1-D moving flows. We describe our recent work including 3-D radiation transfer in PHOENIX and particularly including moving flows exactly using a novel affine method. We briefly discuss quantitative spectroscopy in supernovae.Comment: 13 pages, 9 figures, to appear in Recent Directions in Astrophysical Quantitative Spectroscopy and Radiation Hydrodynamics, Ed. I. Hubeny, American Institute of Physics (2009

Hazard Detection Software for Lunar Landing

The Autonomous Landing and Hazard Avoidance Technology (ALHAT) Project is developing a system for safe and precise manned lunar landing that involves novel sensors, but also specific algorithms. ALHAT has selected imaging LIDAR (light detection and ranging) as the sensing modality for onboard hazard detection because imaging LIDARs can rapidly generate direct measurements of the lunar surface elevation from high altitude. Then, starting with the LIDAR-based Hazard Detection and Avoidance (HDA) algorithm developed for Mars Landing, JPL has developed a mature set of HDA software for the manned lunar landing problem. Landing hazards exist everywhere on the Moon, and many of the more desirable landing sites are near the most hazardous terrain, so HDA is needed to autonomously and safely land payloads over much of the lunar surface. The HDA requirements used in the ALHAT project are to detect hazards that are 0.3 m tall or higher and slopes that are 5 or greater. Steep slopes, rocks, cliffs, and gullies are all hazards for landing and, by computing the local slope and roughness in an elevation map, all of these hazards can be detected. The algorithm in this innovation is used to measure slope and roughness hazards. In addition to detecting these hazards, the HDA capability also is able to find a safe landing site free of these hazards for a lunar lander with diameter .15 m over most of the lunar surface. This software includes an implementation of the HDA algorithm, software for generating simulated lunar terrain maps for testing, hazard detection performance analysis tools, and associated documentation. The HDA software has been deployed to Langley Research Center and integrated into the POST II Monte Carlo simulation environment. The high-fidelity Monte Carlo simulations determine the required ground spacing between LIDAR samples (ground sample distances) and the noise on the LIDAR range measurement. This simulation has also been used to determine the effect of viewing on hazard detection performance. The software has also been deployed to Johnson Space Center and integrated into the ALHAT real-time Hardware-in-the-Loop testbed

Phosphinogold(I) dithiocarbamate complexes : effect of the nature of phosphine ligand on anticancer properties

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Repellent Surface Applications for Pest Birds

Common pest birds in the United States include the non-native European starling (Sturnus vulgaris), house sparrow (Passer domesticus), and the pigeon (Columba livia domestica), as well as native birds including Canada geese (Branta canadensis) and gull species (Laridae). Large concentrations of pest birds can create human health hazards and monetary losses due to consumption of crops, depredation, and fecal contamination and accumulation. Fecal contamination hazards include the potential spread of zoonotic diseases including antimicrobial-resistant zoonoses and human injury due to the accumulation of fecal material on walking surfaces. Additionally, fecal accumulation causes structural and aesthetic damage due to the accelerated deterioration of building materials and increased maintenance costs. Methods to alleviate hazards and damages from aggregations of pest birds are needed. In a series of 3 experiments conducted in Fort Collins, Colorado, USA, between 2016 and 2018, we evaluated 3 surface-application repellent formulations for the reduction of fecal accumulations due to European starlings: Airepel® HC with castor oil, an anthraquinone-based repellent; Airepel HC with castor oil without anthraquinone; and MS2, a novel inert formulation with a tacky, oily texture. We compared each formulation directly to an untreated control. All 3 formulations reduced fecal accumulations beneath treated aluminum perches as compared to fecal accumulations beneath untreated aluminum perches. Interestingly, both formulations that contained no anthraquinone worked equally well or better than Airepel HC with castor oil, the anthraquinone-based formulation. The benefits of an exclusively inert formulation include less risk to applicators and non-target species. Comprehensive experimental field testing of these surface-application repellent formulations is warranted

Overview and Evaluation of a Computational Bone Physiology Modeling Toolchain and Its Application to Testing of Exercise Countermeasures

Prolonged microgravity exposure disrupts natural bone remodeling processes and can lead to a significant loss of bone strength, increasing injury risk during missions and placing astronauts at a greater risk of bone fracture later in life. Resistance-based exercise during missions is used to combat bone loss, but current exercise countermeasures do not completely mitigate the effects of microgravity. To address this concern, we present work to develop a personalizable, site-specific computational modeling toolchain of bone remodeling dynamics to understand and estimate changes in volumetric bone mineral density (BMD) in response to microgravity-induced bone unloading and in-flight exercise. The toolchain is evaluated against data collected from subjects in a 70-day bedrest study and is found to provide insight into the amount of exercise stimulus needed to minimize bone loss, quantitatively predicting post-study volumetric BMD of control subjects who did not perform exercise, and qualitatively predicting the effects of exercise. Results suggest that, with additional data, the toolchain could be improved to aid in developing customized in-flight exercise regimens and predict exercise effectiveness