Abstract: A method for forming a high purity, copper indium gallium selenide (CIGS) bulk material is disclosed. The method includes sealing precursor materials for forming the bulk material in a reaction vessel. The precursor materials include copper, at least one chalcogen selected from selenium, sulfur, and tellurium, and at least one element from group IIIA of the periodic table, which may be selected from gallium, indium, and aluminum. The sealed reaction vessel is heated to a temperature at which the precursor materials react to form the bulk material. The bulk material is cooled in the vessel to a temperature below the solidification temperature of the bulk material and opened to release the formed bulk material. A sputtering target formed by the method can have an oxygen content of 10 ppm by weight, or less.

Abstract: Embodiments of methods and apparatus for close formation flight are provided herein. In some embodiments, a method for establishing situational awareness during formation flight includes exchanging transponder signals between at least two aircraft, establishing two-way communication links between the at least two aircraft, exchanging telemetry data between the at least two aircraft, and assigning the roles of a leader and a follower to the aircraft.

Abstract: A photovoltaic device includes a plurality of photovoltaic cells disposed in an array in which each cell is adjacent to another cell. Each of the cells includes first and second photovoltaic modules. The first photovoltaic module of each cell is configured to convert a first part of light energy incident thereon into electrical energy and to reflect to the second photovoltaic module of an adjacent cell at least some of a remaining portion of light energy incident thereon. The second photovoltaic module of each cell is configured to convert into electrical energy the remaining portion of the light energy received from the first photovoltaic module of an adjacent cell.

Abstract: Methods and apparatus to harvest renewable energy are provided herein. In some embodiments, a wind-powered aircraft includes an airframe suitable for untethered flight in an open airspace; and an airborne kinetic energy conversion system attached to the airframe, the airborne kinetic energy conversion system comprising a turbine, a generator connected to the turbine, and an electrical storage means connected to the generator.

Abstract: An aircraft assembly includes at least one first wing portion providing a lift force during a horizontal flight, at least one wing opening disposed on a vertical axis of the at least one first wing portion, at least one vertical thruster positioned inside the at least one wing opening to provide vertical thrust during a vertical flight, and a mounting system including an open frame portion in a frame of the aircraft and at least one attachment member disposed in the open frame portion to attach at least one pod to the open frame portion in the aircraft frame. The aircraft assembly can further include at least one pod including a mounting frame to attach to the mounting system and a cabin to contain at least one of cargo and passengers.

Abstract: A method is provided for converting optical energy to electrical energy in a spectrally adaptive manner. The method begins by directing optical energy into a first photovoltaic module that includes non-single crystalline semiconductor layers defining a junction such that a first spectral portion of the optical energy is converted into a first quantity of electrical energy. A second spectral portion of the optical energy unabsorbed by the first module is absorbed by a second photovoltaic module that includes non-single crystalline semiconductor layers defining a junction and converted into a second quantity of electrical energy. The first quantity of electrical energy is conducted from the first module to a first external electrical circuit along a first path. The second quantity of electrical energy is conducted from the second module to a second external electrical circuit along a second path that is in parallel with the first path.

Abstract: Embodiments of methods and apparatus for close formation flight are provided herein. In some embodiments, a method of sensing three dimensional (3D) airflow by an aircraft includes: collecting measurements characterizing airflow near the aircraft; analyzing the collected measurements; creating, by a processor, a computer model predicting one or more 3D airflow patterns parameter values based on the analyzing; obtaining one or more additional measurements characterizing airflow near an aircraft of the plurality of aircraft, and evaluating an error between an airflow parameter value predicted by the computer model and the one or more additional measurement.

Abstract: Embodiments of methods for providing distributed airborne wireless communications are provided herein. In some embodiments, a method of providing wireless communication services includes: receiving a radio frequency (RF) signal from a first area by a distributed airborne communication payload, wherein the distributed airborne communication payload is comprised of sections located on respective ones of a plurality of airborne platforms; relaying the RF signal along the sections located on different airborne platforms; and transmitting the RF signal to a second area.

Abstract: A method and apparatus for forming a thin film of a copper indium gallium selenide (CIGS)-type material are disclosed. The method includes providing first and second targets in a common sputtering chamber. The first target includes a source of CIGS material, such as an approximately stoichiometric polycrystalline CIGS material, and the second target includes a chalcogen, such as selenium, sulfur, tellurium, or a combination of these elements. The second target provides an excess of chalcogen in the chamber. This can compensate, at least in part, for the loss of chalcogen from the CIGS-source in the first target, resulting in a thin film with a controlled stoichiometry which provides effective light absorption when used in a solar cell.

Abstract: Embodiments of methods and apparatus for close formation flight are provided herein. In some embodiments, an apparatus for close formation flight, comprises a plurality of sensors for collecting measurements characterizing airflow near an aircraft. The plurality of sensors are attachable to at least one of a wing, fuselage, or tail of the aircraft, and the measurements provide information about airflow velocity in a direction transverse to a direction of the aircraft flight.

Abstract: A method and apparatus of forming compositionally homogeneous particles is provided. The method includes forming a homogenous melt from a plurality of constituent materials under a first pressure sufficient to prevent substantial vaporization of the constituent materials. Droplets are generated from the homogenous melt. The droplets are cooled under a second pressure sufficient to prevent substantial vaporization of the constituent materials at least until the homogeneous particles formed therefrom have stabilized.

Abstract: A mobile system includes a self-supporting platform, a tunable anti-reflective (AR) skin or film disposed on and secured to the mobile platform, one or more actuators and a controller. The tunable AR skin or film includes one or more layers that are at least partially transmitting to optical energy at one or more optical wavelengths. The skin or film is substantially flexible and/or stretchable and has an optical AR to incident electromagnetic radiation of a given wavelength which is selectively variable when flexed and/or stretched. The actuators are able to flex and/or stretch the skin or film in response to receipt of a control signal. The controller generates the control signal based on a measured value of the electromagnetic radiation transmitted through the tunable AR skin or film.

Abstract: A hydro-thermal exchange unit (HTEU) for desalinating feed water in accordance with a humidification-dehumidification includes feed water, fresh water and gas conduit circuits for transporting feed water, fresh water, and gas, respectively. The unit also includes an evaporator through which a portion of the feed water conduit and the gas conduit pass. The evaporator causes evaporation of a portion of the feed water to produce vapor that is transported through the gas conduit. The unit also includes a condenser through which a portion of the gas conduit and the fresh water conduit pass. The condenser has input and output ports for coupling the gas and fresh water conduit circuits. The condenser extracts moisture from the vapor transported therethrough by the gas conduit. The extracted moisture is discharged through the fresh water conduit.

Abstract: Embodiments of the present invention provide an alternative distributed airborne transportation system. In some embodiments, a method for distributed airborne transportation includes: providing an airborne vehicle with a wing and a wing span, having capacity to carry one or more of passengers or cargo; landing of the airborne vehicle near one or more of passengers or cargo and loading at least one of passengers or cargo; taking-off and determining a flight direction for the airborne vehicle; locating at least one other airborne vehicle, which has substantially the same flight direction; and joining at least one other airborne vehicle in flight formation and forming a fleet, in which airborne vehicles fly with the same speed and direction and in which adjacent airborne vehicles are separated by distance of less than 100 wing spans.

Abstract: A hydro-thermal exchange unit (HTEU) for desalinating feed water in accordance with a humidification-dehumidification includes feed water, fresh water and gas conduit circuits for transporting feed water, fresh water, and gas, respectively. The unit also includes an evaporator through which a portion of the feed water conduit and the gas conduit pass. The evaporator causes evaporation of a portion of the feed water to produce vapor that is transported through the gas conduit. The unit also includes a condenser through which a portion of the gas conduit and the fresh water conduit pass. The condenser has input and output ports for coupling the gas and fresh water conduit circuits. The condenser extracts moisture from the vapor transported therethrough by the gas conduit. The extracted moisture is discharged through the fresh water conduit.

Abstract: An ice resistant structure is provided which includes a self-supporting, structural platform, a retaining, protective layer and a subsurface anti-icing (AI) and/or de-icing (DI) layer. The retaining, protective layer is disposed over the self-supporting, structural platform. The subsurface anti-icing (AI) and/or de-icing (DI) layer is located between the self-supporting, structural platform and the retaining, protective layer. The subsurface Al and/or DI layer is a functional layer such that an Al and/or DI agent is released to a surface of the retaining protective layer by an activation mechanism responsive to a change in an environmental condition.

Abstract: Embodiments of air flow sensing systems are provided herein. In some embodiments, one or more sensors are positionable on an aircraft and dimensioned and arranged to measure vector components of airflow velocity having at least one of a transverse or streamwise direction relative to a flight direction of the aircraft. In some embodiments, the one or more sensors are positioned in front of an aircraft wing and distributed as an array of sensors along the span of the aircraft wing.

Abstract: An aircraft for vertical take-off and landing includes an aircraft assembly which includes at least one first wing portion providing a lift force during a horizontal flight, at least one wing opening disposed on a vertical axis of the at least one first wing portion and at least one propeller-based thruster positioned inside the at least one wing opening to provide vertical thrust during a vertical flight. The aircraft assembly can further include air vents positioned inside at least one of the wing openings. The air vents can further include louvres positioned over or under the air vents to open and close the wing openings. The thruster can further be used to provide flight control for the aircraft.

Abstract: A method is provided for fabricating a thin-film semiconductor device. The method includes providing a plurality of raw semiconductor materials. The raw semiconductor materials undergo a pre-reacting process to form a homogeneous compound semiconductor material. This pre-reaction typically includes processing above the liquidus temperature of the compound semiconductor. The compound semiconductor material is reduced to a particulate form and deposited onto a substrate to form a thin-film having a composition and atomic structure substantially the same as a composition and atomic structure of the compound semiconductor material.

Abstract: Embodiments of methods for providing distributed airborne wireless communications are provided herein. In some embodiments, a method of providing wireless communication services includes: receiving a radio frequency (RF) signal from a first area by a distributed airborne communication payload, wherein the distributed airborne communication payload is comprised of sections located on respective ones of a plurality of airborne platforms; relaying the RF signal along the sections located on different airborne platforms; and transmitting the RF signal to a second area.