Abstract: Disclosed is a drone-assisted and non-drone assisted NLoS-FSOC network and method for high-speed communications in disaster-struck areas or where there is little or no communications. NLoS-FSOC uses a diffuse reflector that is in LoS of a transmitter and receiver for establishing a broadcast optical channel. NLoS-FSOC establishes uplink and downlink transmissions. The present disclosure services at least 130% more stations and provides at least 100% more aggregated downlink data rates than drone-assisted than RF-based schemes. It also consumes 116 times less energy compared to RF-based schemes by using high-bandwidth optical signals and coherent light of laser light in NLoS-FSOC, optical broadcast channel use, and drone or non-drone front-haul diffuse reflection placement. The present disclosure is used autonomously or in combination with other systems such as RF schemes for a more robust solution to RF schemes alone.

Abstract: Copolymers and compositions containing copolymers having advantageous viscosity, friction reduction, dissolution, pH-stability, and temperature-stability are provided. These copolymers can be used as rheology modifiers for oil field applications.

Abstract: A method and a system for rail transit communication. The method includes: selecting a second target FSO transceiver from the FSO transceivers that are currently located within a signal coverage of a target FSO base station, in response to detecting that a first target free-space-optics (FSO) transceiver moves out of the signal coverage of the target FSO base station when data communication between the target FSO base station and the target user terminal is performed via the first target FSO transceiver, where the target FSO base station is one of the FSO base stations located on the rail; and maintaining the data communication between the target FSO base station and the target user terminal, by using the second target FSO transceiver. Handover among the base stations is reduced for user equipment, data communication rate is increased, and communication experience of passengers can be improved.

Abstract: The present disclosure provides to a power converter including an AC input terminal (ACin), a neutral terminal (N), an AC output terminal (ACout), an AC/DC converter circuit (210) connected between the AC input terminal, a positive DC terminal (DCP), and a negative DC terminal (DCN), a DC capacitor (C15) connected between the positive DC terminal (DCP) and the negative DC terminal (DCN), a line frequency commutated neutral circuit (220) connected between the positive DC terminal (DCP), the negative DC terminal (DCN), and the neutral terminal (N), and a DC/AC converter circuit (230) connected between the positive DC terminal (DCP), the negative DC terminal (DCN), the AC output terminal (ACout), and the neutral terminal (N). The power converter further includes an auxiliary converter circuit (240) connected between the positive DC terminal (DCP), the negative DC terminal (DCN), and the neutral terminal (N).

Abstract: Drilling fluid compositions and methods of using them are described. The drilling fluid compositions comprise nanocomposites comprising core-shell morphology, wherein the core material comprises a nanoparticle having an average particle size of about 5 nm to 100 nm, and the shell material comprises a crosslinked polymer comprising acrylamide repeat units. The nanocomposites are effective fluid loss control agents when the drilling fluids are employed in mud drilling operations.

Abstract: Energy packet switches (EPS) employing supercapacitors as storage provide aggregation and delivery of energy to users based on shared-capacitance in a digital power grid. The EPS aggregates energy from one or multiple energy sources, stores and dispatches the energy in discrete amounts as energy packets to one or multiple users. The payload of the energy packet is adjusted by the voltages of the supercapacitors which are used as energy containers for both the EPS and the users. The EPS has a control plane where data transmitted is used to control the operation of the EPS, and a power plane to receive and transmit energy between ports. The power and data planes work in parallel and with a parallel data network. Control and management of the EPS are based on a request-grant transport protocol. The data network is used to receive energy requests and grants, and a granting scheme is used to select which loads are granted energy.

Abstract: The present disclosure provides to a power converter including an AC input terminal (ACin), a neutral terminal (N), an AC output terminal (ACout), an AC/DC converter circuit (210) connected between the AC input terminal, a positive DC terminal (DCP), and a negative DC terminal (DCN), a DC capacitor (C15) connected between the positive DC terminal (DCP) and the negative DC terminal (DCN), a line frequency commutated neutral circuit (220) connected between the positive DC terminal (DCP), the negative DC terminal (DCN), and the neutral terminal (N), and a DC/AC converter circuit (230) connected between the positive DC terminal (DCP), the negative DC terminal (DCN), the AC output terminal (ACout), and the neutral terminal (N). The power converter further includes an auxiliary converter circuit (240) connected between the positive DC terminal (DCP), the negative DC terminal (DCN), and the neutral terminal (N).

Abstract: Copolymers and compositions containing copolymers having advantageous viscosity, friction reduction, dissolution, pH-stability, and temperature-stability are provided. These copolymers can be used as rheology modifiers for oil field applications.

Abstract: Energy packet switches (EPS) employing supercapacitors as storage provide aggregation and delivery of energy to users based on shared-capacitance in a digital power grid. The EPS aggregates energy from one or multiple energy sources, stores and dispatches the energy in discrete amounts as energy packets to one or multiple users. The payload of the energy packet is adjusted by the voltages of the supercapacitors which are used as energy containers for both the EPS and the users. The EPS has a control plane where data transmitted is used to control the operation of the EPS, and a power plane to receive and transmit energy between ports. The power and data planes work in parallel and with a parallel data network. Control and management of the EPS are based on a request-grant transport protocol. The data network is used to receive energy requests and grants, and a granting scheme is used to select which loads are granted energy.

Abstract: A method and a system for rail transit communication. The method includes: selecting a second target FSO transceiver from the FSO transceivers that are currently located within a signal coverage of a target FSO base station, in response to detecting that a first target free-space-optics (FSO) transceiver moves out of the signal coverage of the target FSO base station when data communication between the target FSO base station and the target user terminal is performed via the first target FSO transceiver, where the target FSO base station is one of the FSO base stations located on the rail; and maintaining the data communication between the target FSO base station and the target user terminal, by using the second target FSO transceiver. Handover among the base stations is reduced for user equipment, data communication rate is increased, and communication experience of passengers can be improved.

Abstract: An electric multimode power converter module includes an AC/DC converter, including a first AC port; a DC/AC converter, including a second AC port; a DC/DC converter, including a DC port; a controller; and a communication bus interconnecting the converters. The controller includes a hardware configuration port and sets the module in the following states, based on the value read from the configuration port: a first state in which the module transfers power between the first AC port and the DC port, a second state in which the module transfers power between the DC port and the second AC port, and a third state in which the module transfers power between the AC ports and the DC port. A power supply system includes a shelf device including at least one compartment, and an electric multimode power converter module as mentioned above is inserted in the at least one compartment.

Abstract: Methods of treating a well bore within an underground formation are disclosed. These methods include: (a) preparing a treatment composition by mixing a polyol-containing component and a polyisocyanate-containing component; and (b) introducing the treatment composition into the well bore. The polyol-containing component includes a polymeric polyol having a viscosity at 25° C. of no more than 1000 mPa·s and the isocyanate-containing component includes an unblocked (cyclo)aliphatic polyisocyanate polymer including allophanate groups and having a viscosity at 25° C. and at least 99% solids of no more than 1000 mPa·s.

Abstract: An AC-AC converter device includes first and second AC input terminals and first and second AC output terminals. An input device is connected between an input node, a common node, a positive DC terminal and a negative DC terminal, wherein the input node is connected to the first AC input terminal via a first input inductor. An output device is connected between an output node, the positive DC terminal and the negative DC terminal, wherein the output node is connected to the first AC output terminal via an output inductor. A common device is connected between the common node, the positive DC terminal and the negative DC terminal, where the common node is connected to the second AC input terminal via a common inductor. A control device is provided for controlling the switches of the output device and the common device.

Abstract: Methods and apparatus for packetized energy distribution are provided. A data and power delivery network, called a digital grid, is provided to facilitate delivery of power upon request. Energy bits (quanta) serve as a means to deliver energy as well as coding. Voltage pulses of varying time scales are used for coding and current levels help to accurately meet customer's demand. Energy is sent as packets (a combination of energy bits), and specific energy packets are addressed to specific customers permitting accurate monitoring and distribution of electrical energy.

Abstract: An electric multimode power converter module includes an AC/DC converter, including a first AC port; a DC/AC converter, including a second AC port; a DC/DC converter, including a DC port; a controller; and a communication bus interconnecting the converters. The controller includes a hardware configuration port and sets the module in the following states, based on the value read from the configuration port: a first state in which the module transfers power between the first AC port and the DC port, a second state in which the module transfers power between the DC port and the second AC port, and a third state in which the module transfers power between the AC ports and the DC port. A power supply system includes a shelf device including at least one compartment, and an electric multimode power converter module as mentioned above is inserted in the at least one compartment.

Abstract: Methods and apparatus for packetized energy distribution are provided. A data and power delivery network, called a digital grid, is provided to facilitate delivery of power upon request. Energy bits (quanta) serve as a means to deliver energy as well as coding. Voltage pulses of varying time scales are used for coding and current levels help to accurately meet customer's demand. Energy is sent as packets (a combination of energy bits), and specific energy packets are addressed to specific customers permitting accurate monitoring and distribution of electrical energy.

Abstract: Drilling fluid compositions methods of using them are described. The drilling fluid compositions comprise nanocomposites comprising core-shell morphology, wherein the core material comprises a nanoparticle having an average particle size of about 5 nm to 100 nm, and the shell material comprises a crosslinked polymer comprising acrylamide repeat units. The nanocomposites are effective fluid loss control agents when the drilling fluids are employed in mud drilling operations.

Abstract: A garden tool device facilitates manipulation of soil, removal or cutting of weeds, cleaning joints between concrete, landscape design and the like. The device includes a head and a handle. A perimeter edge of the head defines a rectangular parallelogram. Each of a plurality of grooves extends into the perimeter edge of the head. The grooves are spaced along the perimeter edge of the head. The handle is coupled to and extends from the head.

Abstract: Technologies are generally described for measuring clock skew between two remote hosts connected through a computer network. According to some examples, pairs of probe packets, also referred to as a compound probe, may be transmitted over an end-to-end path in both directions (forward and reverse paths) to measure a gap value at the end nodes for clock skew estimation. Compound probes may arrive at the end nodes with a zero dispersion gap (no separation) and the gap values along the forward and reverse paths may be determined by a capacity of the links connected to the end nodes added to the clock speeds of the measuring nodes upon arriving at the end nodes. The link capacity is a constant network parameter. Thus, the ratio of the measured gap values may provide an estimate of clock speed discrepancy between the end nodes.

Abstract: Technologies are generally described to determine a download throughput of a wireless connection in an environment hosting multiple wired and wireless connections. According to some examples, a compound probe may be transmitted from a source to a wireless destination. Another compound probe may also be transmitted from the source to the wireless destination. The compound probes may include multiple packets without any dispersion gap. Next, an average intra-packet gap (AIPG) and a minimum intra-packet gap (MIPG) may be determined from the first compound probe. Furthermore, another MIPG may be determined from the later compound probe. The download throughput from the source to the wireless destination may be computed from the AIPG and the MIPGs.