3,025 research outputs found
Flexible conducting electrodes based on an embedded double-layer structure of gold ribbons and silver nanowires
No full textIn this study, we present a flexible and highly conductive double-layer structure of gold ribbons (Au RBs) and silver nanowires (Ag NWs) embedded in flexible elastomeric substrates. By using prism-type micro-patterns of n-paraffin (eicosane, C20H42) as templates, Au RBs and Ag NWs were sequentially deposited on bare Si surfaces between the micro-patterns by conducting galvanic displacement (GD) and solution casting. As the resulting double-layer structure was transferred to a thin layer of poly(dimethyl siloxane) (PDMS) by mechanical detachment after removing the micropatterns, the embedded double-layer structures were consequently produced in the PDMS layer. Interestingly, it was observed that the embedded double-layer of Au RBs and Ag NWs improved electrical properties in comparison with the individual values of the components. The resulting flexible conductors were also characterized by detecting changes in electrical signals under various types of mechanical deformation such as bending or stretching. Moreover, an AC voltage-driven electrochemiluminescent (ECL) device was successfully demonstrated by using the embedded double-layer of Au RBs and Ag NWs as an electrode.
Fabrication of Grid-Type Transparent Conducting Electrodes Based on Controlled Mechanical Fracture
No full textHerein, we developed a unique and effective method to fabricate the silver networks embedded in flexible substrates by controlling mechanical fracture in the oxidized surface of elastomers for a highly transparent conducting electrode (TCE). A brittle silica-like layer on a poly(dimethyl siloxane) (PDMS) was generated by carrying out UV/ozone treatment. Then, cracks were uniformly produced in the silica-like layer by bending the elastic substrates at different stains. After the PDMS replica with crack patterns was produced, silver ink was filled into the cracks and sintered to form conducting networks embedded in the PDMS substrate. The resulting highly transparent and conductive electrode was mechanically robust to bending strains. The silver networks-based TCEs was successfully applied to emissive electrochemiluminescent (ECL) devices.
Letter to F.D. Moon from A. Mitchell Salone regarding information about and photos of the Colored School in Wewoka
No full textLetter to F.D. Moon regarding a book being written on African American schools. The author asks for photos of the school and shows appreciation for how he runs the school
EMI Reduction Method in Wireless Power Transfer System with Increasing Efficiency using Frequency Split Phenomena
No full textThis paper describes a method to reduce magnetic field leakage from a Wireless Power Transfer (WPT) systems. By using frequency split phenomena, the reactive shield can reduce the magnetic field of the target frequency band with increasing power transfer efficiency. The simulation results of the suggested reactive shielding coil structure are verified with a 50 W-WPT system
We Reach the Moon. Title page inscribed by the author.
No full textOn 20 July 1969, Neil Armstrong and Buzz Aldrin became the first humans to land on the moon. The achievement inspired a host of products and memorabilia. On display from the publishing collection of Seymour Lawrence is both the German and American editions of the children’s 1969 picture book Journey to the Moon by artist Erich Fuchs who depicts the eight-day voyage with cubist modernism. The author of We Reach the Moon was the New York Times science reporter, and he inscribed his paperback to Mississippi writer Willie Morris and family.https://egrove.olemiss.edu/space_exhibit_2020/1012/thumbnail.jp
On lunar collision orbits: New methodologies for Moon-to-Moon transfer design
No full textMany interplanetary missions massively leverage the lunar gravitational pull in the so-called low-energy regime to converge to their aim, saving consistent amount of fuel. Among these, two future Japanese spacecraft are expected to repeatedly encounter the Moon along their trajectories to either facilitate the escape from the Earth–Moon system or opportunely target a specific region in its neighbourhood. Although never actively employed for preliminary trajectory design, lunar collision orbits have shown a rich dynamical structure and an applicability for both medium- and low-energy regimes. These characteristics, together with their intrinsic nature of being close to trajectories experiencing lunar fly-by, have encouraged this research. In this work, lunar collision orbits are employed to delineate a method for obtaining ballistic transfers between two successive lunar encounters, briefly addressed as Moon-to-Moon. This study is first carried out with the assumptions of the autonomous Circular Restricted Three-Body Problem, subsequently extended to the nonautonomous Bi-circular Restricted Four-Body Problem, including the solar gravitational influence.Poincaré cuts are extensively used as a dimensionality reductant for lunar collision orbits: this allows to ascertain their similar behaviour with trajectories flybying the Moon, whose characteristics are partly foreseen by determining the associated intersection with the same cut. A patching is performed at the cut to obtain both single and multiple ballistic Moon-to-Moon transfers. The strict bond of lunar collision orbits with the invariant manifolds of simple periodic orbits about Lagrangian points is confirmed and exploited to design ballistic itineraries connecting highly elliptic orbits about the Earth to horizontal Lyapunov orbits of the Earth–Moon system, via a single Moon-to-Moon transfer. With the usage of the lunar collision orbits and the Poincaré cut, a simple optimization technique is implemented to retrieve a properly defined Moon-to-Moon transfer from a trajectory missing a second fly-by with the Moon. Including the presence of the Sun, a similar method for obtaining single and multiple Moon-to-Moon transfers is developed. A classification of lunar double-collision transfers is then performed within the same framework, highlighting their similarity with other studies in past literature, eventually leading to the construction of a database of Moon-to-Moon transfers. The latter, conceived as an improvement with respect to the former version by adding the lunar gravitational influence, shows its applicability in real preliminary trajectory design.Aerospace Engineerin
Moon Dog [Translation]
No full textA Japanese to English translation of the poem Moon Dog originally written by Mizuho Ishid
New solar-sail orbits for polar observation of the earth and moon
No full textIn this paper, a new family of solar-sail periodic orbits with adequate properties for polar observation of the Earth and moon is developed under the simplified but nonautonomous dynamics of the solar-sail augmented Earth–moon circular restricted three-body problem. The novel orbits, termed “distant-circular orbits,” are found through differential correction and continuation and employ a simple sun-facing steering law for the solar sail. A basic coverage analysis shows that one of the distant-circular orbits is capable of providing continuous coverage of both the Earth’s and lunar north (or south) poles with just a single sailcraft at a minimum elevation angle of 14 deg and an average range of six Earth–moon distances. Moreover, simple transfer trajectories between orbits of the family are found, so that the sailcraft can switch between observing the northern and southern latitudes of the Earth and moon during a single mission. Subsequently, using multiple-shooting differential correction, all results are migrated to a higher-fidelity dynamic framework that considers, among others, the eccentricity of the moon’s orbit. The perturbations cause the periodicity of the orbits to break, turning them into seemingly quasi-periodic orbits, but it is shown that the coverage capabilities are maintained. Finally, an active control strategy is developed to counteract part of the perturbing effects such that, by appropriately steering the sail, the apparent quasi-periodicity of the orbits is enhanced and the deviation from the unperturbed orbits is reduced.Accepted Author ManuscriptAstrodynamics & Space Mission
Half Moon Lake School District No. 2785
No full textPhotograph - Students, likely at Half Moon Lake School, near Waugh, Alberta. Teacher is P. Kowalski. ATS 4-59-23-W
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Impact origin of the Moon
No full textA few years after the Apollo flights to the Moon, it became clear that all of the existing theories on the origin of the Moon would not satisfy the growing body of constraints which appeared with the data gathered by the Apollo flights. About the same time, researchers began to realize that the inner (terrestrial) planets were not born quietly -- all had evidences of impacts on their surfaces. This fact reinforced the idea that the planets had formed by the accumulation of planetesimals. Since the Earth`s moon is unique among the terrestrial planets, a few researchers realized that perhaps the Moon originated in a singular event; an event that was quite probable, but not so probable that one would expect all the terrestrial planets to have a large moon. And thus was born the idea that a giant impact formed the Moon. Impacts would be common in the early solar system; perhaps a really large impact of two almost fully formed planets of disparate sizes would lead to material orbiting the proto-earth, a proto-moon. This idea remained to be tested. Using a relatively new, but robust, method of doing the hydrodynamics of the collision (Smoothed-Particle Hydrodynamics), the author and his colleagues (W. Benz, Univ. of Arizona, and A.G.W. Cameron, Harvard College Obs.) did a large number of collision simulations on a supercomputer. The author found two major scenarios which would result in the formation of the Moon. The first was direct formation; a moon-sized object is boosted into orbit by gravitational torques. The second is when the orbiting material forms a disk, which, with subsequent evolution can form the Moon. In either case the physical and chemical properties of the newly formed Moon would very neatly satisfy the physical and chemical constraints of the current Moon. Also, in both scenarios the surface of the Earth would be quite hot after the collision. This aspect remains to be explored
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