Abstract: Receivers for use in solar energy collector systems and solar-powered electrical energy generating plants are provided. The receivers comprise a solar radiation absorbing core that converts absorbed solar radiation to thermal energy. The core comprises a refractory material to allow the receivers to operate continuously at high temperatures reached by absorbing concentrated solar radiation. The thermal energy so generated in the core may be stored in the receiver for a transitory period, or for a more extended period. Receivers may comprise one or more fluid channels in and/or around the core for conveying a working fluid to facilitate extraction of stored thermal energy from the core.

Abstract: A measuring device comprising a base, feet connected to the base, and an inclinometer mounted on the base is used to characterize a surface. The feet are placed in direct contact with the surface at a predetermined position. The inclinometer measures the angle of the surface relative to gravity at the predetermined position. In some embodiments, multiple measuring devices are connected to an arm, in order to measure different positions on the surface simultaneously. The arm may be moved by an actuator to the next predetermined position on the surface. In some embodiments, multiple measuring devices are connected to a frame that is substantially the same size as the surface to be characterized, such that the entire surface can be characterized without moving the frame.

Abstract: A receiving device in a trunked radio communications system determines a transmit frequency, wherein the transmit frequency is calculated by subtracting a voice channel number from 759, multiplying by a channel spacing and adding a base frequency to yield the transmit frequency. The receiving device determines a receive frequency by a base frequency+[(759?a voice channel number)*25,000 Hz], where the base frequency is at least one of 851.0125 MHz, 851.0250 MHz, and 851.000 MHz. In any case, the voice channel number is communicated in an outbound signaling message defined by Motorola's 3600-baud radio trunking protocol.

Abstract: A system for effecting cooling of a coolant fluid is provided, the system comprising: a solar energy collector system; and fluid channels for the coolant fluid that are at least partially above ground level and are at least partially shaded by the solar energy collector system. The system may comprise a system for cooling a condenser coolant fluid in a thermal power plant incorporating a solar energy collector system, the system comprising: one or more solar energy reflectors; and fluid channels for the coolant fluid that are at least partially above ground level and are at least partially shaded by one or more of the solar energy reflectors. Solar energy reflector carrier arrangements for use in said system, and methods and thermal power plants utilizing said system are further provided.

Abstract: A receiving device in a trunked radio communications system determines a transmit frequency, wherein the transmit frequency is calculated by subtracting a voice channel number from 559, multiplying by a channel spacing and adding a base frequency to yield the transmit frequency, if the voice channel number is between 559 and 320. The receiving device determines a receive frequency by 851.0250 MHz+[(559?a voice channel number)*12,500 Hz], if the voice channel number is between 559 and 320. In any case, the voice channel number is communicated in an outbound signaling message defined by Motorola's 3600-baud radio trunking protocol.

Abstract: Combined cycle power plants and related methods are disclosed here. In the plants, a mediating thermal energy storage unit is used to store waste or residual thermal energy recovered from a heat engine employing a top thermodynamic cycle of the combined cycle power plant, so that the stored residual thermal energy may be used as an energy source in a bottom thermodynamic cycle of the power plant. In the combined cycle power plants described here, the heat engine employing a top cycle may comprise a Brayton cycle heat engine and the heat engine employing the bottom thermodynamic cycle may be a Rankine cycle heat engine.

Abstract: The invention provides compositions for use in thermal energy storage systems, including thermal energy storage mediums, fluid channeling devices and thermally conductive heat transfer elements, and methods for storing thermal energy. A thermal energy storage system is provided, comprising: (a) a granular thermal energy storage medium comprising at least a first size class and a second size class; wherein the individual granules of each size class deviate from the average granular size for that size class by no more than about ±50%; wherein first size class is the largest size class; wherein the ratio of the average size of the first size class to the average size of the second size class is at least about 2:1; and (b) one or more conduits disposed within the medium, and arranged to receive a source of thermal energy.

Abstract: The present application provides a solar energy receiver comprising an effective absorption aperture that is biased, so that solar radiation from a certain direction can be preferentially absorbed by a solar radiation absorber in the receiver. The effective absorption aperture is inclined relative to a physical aperture. Thus, in an elevated receiver comprising a downward facing physical aperture defining a plane that is relatively parallel to ground, the effective absorption aperture of the receivers described herein may be inclined relative to ground, but the physical aperture may remain generally parallel to ground. The biased receivers may be used in Linear Fresnel Reflector solar arrays.

Abstract: Described herein are solar energy collector systems, components for solar energy collector systems, and methods for installing solar energy collector systems. The components for solar energy collector systems include but are not limited to solar radiation absorbers, receivers, drives, drive systems, reflectors, and various support structures. The solar energy collection systems, solar radiation absorbers, receivers, drives, drive systems, reflectors, support structures, and/or methods may be used, for example, in LFR solar arrays. Improved solar radiation absorbers, receivers and related methods are described here.

Abstract: Described herein are solar energy collector systems, components for solar energy collector systems, and methods for installing solar energy collector systems. The components for solar energy collector systems include but are not limited to solar radiation absorbers, receivers, drives, drive systems, reflectors, and various support structures. The solar energy collection systems, solar radiation absorbers, receivers, drives, drive systems, reflectors, support structures, and/or methods may be used, for example, in LFR solar arrays. Drives and drive systems are described herein that may provide improved rotational positioning, movement, and/or rotational positional sensing. For example, drives and drive systems are provided which allow operation through a variable frequency drive. The components and methods described herein may be used together in any combination in a solar collector system, or they may be used separately in different solar collector systems.

Abstract: Described herein are solar energy collector systems, components for solar energy collector systems, and methods for installing solar energy collector systems. The components for solar energy collector systems include but are not limited to solar radiation absorbers, receivers, drives, drive systems, reflectors, and various support structures. The solar energy collection systems, solar radiation absorbers, receivers, drives, drive systems, reflectors, support structures, and/or methods may be used, for example, in LFR solar arrays.

Abstract: System and method for efficiently managing communication channel assignments within talkgroups having dual mode communication units capable of operating on a first communication channel type and on a second communication channel type, and single mode communication units capable of operating only on the first communication channel type. If, at a base site, each of the communication units associated with a talkgroup is a dual mode communication unit, a call for that talkgroup is assigned to be broadcast using a channel of the first communication channel type. If, at least one of the communication units associated with the talkgroup at the base site is a single mode communication unit, the call for that talkgroup is assigned to a channel of the second communication channel type. As communication units roam between sites, channel assignments are continuously updated based on the types of communication units at each base site at any one time.

Abstract: A method and system for assigning priority to a talk group of a plurality of talk groups in a communication network (100) is provided. The method includes detecting (304) activity on a first talk group (108) via a Vehicular Repeater (VR) (106). The first talk group is associated with a lower priority than that of a second talk group (110). The method also comprises assigning (306) a higher priority to the first talk group and the lower priority to the second talk group, based on the step of detecting. Further, the method comprises dynamically re-assigning (308) the higher priority and the lower priority amongst the plurality of talk groups, based on detecting activity.

Abstract: A receiving device in a trunked radio communications system determines a transmit frequency, wherein the transmit frequency is calculated by subtracting a voice channel number from 319, multiplying by a channel spacing and adding a base frequency to yield the transmit frequency, if the voice channel number is between 319 and 0. The receiving device determines a receive frequency by 851.0125 MHz+[(319?a voice channel number)*25,000 Hz], if the voice channel number is between 319 and 0. In any case, the voice channel number is communicated in an outbound signaling message defined by Motorola's 3600-baud radio trunking protocol.

Abstract: An overload protection circuit is disclosed which limits the current supplied by a battery to a load. The circuit is particularly adapted for use in portable radio applications which must meet rigorous specifications of intrinsically safe equipment for use in hazardous environments. Load sensor 20 continuously monitors for the presence of load to enable power switch 16 via switch control 22. Current trip circuit 24 monitors the voltage developed across current sensor 18 to provide a disable signal to switch control 22 in the event of an overload condition. Current limit circuit 26 limits the drive signal to power switch 16. Voltage trip circuit 28 prevents overdissipation of the power switch device. Thus, intrinsically safe battery circuit 30 provides protection such that hazardous gases will not be ignited by sparks or thermal heating during overload conditions.

Abstract: A solar collector element having an inner tube through which a fluid can be passed, an outer glass tube enveloping the periphery of the inner tube and defining an evacuated space between the two tubes, and a solar selective surface coating deposited on the outer surface of the inner tube. The surface coating is deposited as three layers, an inner layer composed of a metal which exhibits high reflectivity in the infra-red spectral range, an outer layer composed of a material which behaves as a semiconductor at collector operating temperatures and an intermediate layer which is composed of a dielectric material.

Abstract: A method and means of transmitting sunlight into the interior of a building by use of a planar solid transparent light deflecting panel or plate which is formed of a plurality of parallel identically spaced apart triangular ribs on one face, with the panel in its vertical orientation, the top slope angle (.gamma.) of each triangular rib, the bottom slope angle (.beta.) of each triangular rib and the included angle (.beta.+.gamma.

Abstract: An ideal or near ideal radiation concentrator for a distant source of radiation or a radiation distributor in which a non concave linear radiation absorber or source is arranged between facing reflecting side walls to receive radiation reflected from the side walls or to emit radiation. One side wall is made up of at least a portion the curvature of which is in accordance with equation (2) of the specification and the other side wall including at least a portion the curvature of which is in accordance with equation (3) of the specification. Where a circular or other convex section absorber or source is employed it is preferred that each side wall commence at a point on the absorber or source, the curvature of the side wall adjacent the absorber or source being the involute of the cross-section of the absorber or source.