72 research outputs found

    Rectifying antenna and method of manufacture

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    In accordance with the present invention, an aperture rectenna is provided where the substrate is transparent and of sufficient mechanical strength to support the fabricated structure above it. An aperture antenna is deposited on the transparent substrate and a metal-insulator-metal (MIM) diode is constructed on top of the aperture antenna. There is an insulating layer between the aperture antenna metal and the metal ground plane optimized to maximize the collection of incident radiation. The top of the structure is capped with a metal ground plane layer, which also serves as the DC connection points for each rectenna element

    High-frequency feed structure antenna apparatus and method of use

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    An antenna apparatus for the reception of, and or transmission of, electromagnetic energy, the apparatus including a non-radiating dielectric waveguide aperture coupled to at least one dielectric rod antenna, which is electromagnetically coupled to a transmission line element

    Dual-polarized feed antenna apparatus and method of use

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    An antenna apparatus and method for the interception of randomly polarized electromagnetic waves utilizing a dual polarized antenna which is excited through a cross-slot aperture using two well-isolated orthogonal feeds

    Light Weight Complex Metal Hydrides for Reversible Hydrogen Storage

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    We have investigated the complex metal hydrides involving light weight elements or compounds for the reversible hydrogen storage. The complex hydrides are prepared via an inexpensive solid state mechanochemical process under reactive atmosphere at ambient temperatures. The complex metal hydride, LiBH4 with different mole concentrations of ZnCl2 were characterized for the new phase formation and hydrogen decomposition characteristics of Zn(BH4)2. Furthermore, the complex metal hydride is destabilized using the addition of nano MgH2 for the reversible hydrogen storage characteristics. The structural, microstructural, surface, and other physicochemical behaviors of these lightweight complex metal hydrides have been studied via various metrological tools such as x-ray diffraction, Fourier transform infrared spectroscopy, thermal programed desorption, and PCT hydrogen absorption methods

    Synthesis, Characterization, and Applications of ZnO Nanowires

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    ZnO nanowires (or nanorods) have been widely studied due to their unique material properties and remarkable performance in electronics, optics, and photonics. Recently, photocatalytic applications of ZnO nanowires are of increased interest in environmental protection applications. This paper presents a review of the current research of ZnO nanowires (or nanorods) with special focus on photocatalysis. We have reviewed the semiconducting photocatalysts and discussed a variety of synthesis methods of ZnO nanowires and their corresponding effectiveness in photocatalysis. We have also presented the characterization of ZnO nanowires from the literature and from our own measurements. Finally, a wide range of uses of ZnO nanowires in various applications is highlighted in this paper

    Nanomaterials for Hydrogen Storage Applications: A Review

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    Nanomaterials have attracted great interest in recent years because of the unusual mechanical, electrical, electronic, optical, magnetic and surface properties. The high surface/volume ratio of these materials has significant implications with respect to energy storage. Both the high surface area and the opportunity for nanomaterial consolidation are key attributes of this new class of materials for hydrogen storage devices. Nanostructured systems including carbon nanotubes, nano-magnesium based hydrides, complex hydride/carbon nanocomposites, boron nitride nanotubes, TiS2/MoS2 nanotubes, alanates, polymer nanocomposites, and metal organic frameworks are considered to be potential candidates for storing large quantities of hydrogen. Recent investigations have shown that nanoscale materials may offer advantages if certain physical and chemical effects related to the nanoscale can be used efficiently. The present review focuses the application of nanostructured materials for storing atomic or molecular hydrogen. The synergistic effects of nanocrystalinity and nanocatalyst doping on the metal or complex hydrides for improving the thermodynamics and hydrogen reaction kinetics are discussed. In addition, various carbonaceous nanomaterials and novel sorbent systems (e.g. carbon nanotubes, fullerenes, nanofibers, polyaniline nanospheres and metal organic frameworks etc.) and their hydrogen storage characteristics are outlined

    Clean Energy and Fuel (Hydrogen) Storage

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    Clean energy and fuel storage are often required for both stationary and automotive applications. Some of these clean energy and fuel storage technologies currently under extensive research and development include hydrogen storage, direct electric storage, mechanical energy storage, solar–thermal energy storage, electrochemical (batteries and supercapacitors), and thermochemical storage. The gravimetric and volumetric storage capacity, energy storage density, power output, operating temperature and pressure, cycle life, recyclability, and cost of clean energy or fuel storage are some of the factors that govern efficient energy and fuel storage technologies for potential deployment in energy harvesting (solar and wind farms) stations and onboard vehicular transportation. This Special Issue thus serves the need for promoting exploratory research and development on clean energy and fuel storage technologies while addressing their challenges to practical and sustainable infrastructures

    Single active layer electrochromic devices

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    In one embodiment, an electrochromic device includes a single active layer configured to be alternately placed in a light-transmitting state in which relatively large amounts of light can be transmitted through the active layer and a light-blocking state in which relatively small amounts of light can be transmitted through the active layer, wherein the device comprises no other layers of material that contribute to transitioning between the two states

    Protection of polymeric/organic materials from photodegradation by encapsulation

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    Structures of a particle containing a core and at least one shell, a metal oxide material of which is necessarily doped to ensure protection of a material of the core from photodegradation. The core can include any of a thermochromic material, a phase-change material, and a judiciously defined auxiliary material that in turn contains organic and/or polymeric material. Derivative products utilizing a plurality of such particles. Methodologies for producing such particles and derivative products
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