Abstract: A two-stage microinverter for coupling a PV panel to a power grid includes a DC/DC converter stage having an input for coupling to the PV panel and a DC/AC inverter stage that has an output for coupling to the grid, with at least one DC link capacitor between the DC/DC converter and DC/AC inverter stage. A synchronous controller that includes a loop compensator coupled to a mixer is between an analog-to-digital converter (ADC) and a phase-locked loop (PLL) for coupling to an output voltage from the grid. The ADC receives a DC link voltage from the DC link capacitor. An output of the PLL is for controlling a timing of sampling by the ADC of the DC link voltage so that the ADC samples the DC link voltage when an AC component of a ripple voltage on the DC link voltage intersects an average value of the DC link voltage.

Abstract: Methods, apparatus and systems for in-situ heating fluids with electromagnetic radiation are provided. An example tool includes a housing operable to receive a fluid flowed through a flow line and a heater positioned within the housing. The heater includes a number of tubular members configured to receive portions of the fluid and an electromagnetic heating assembly positioned around the tubular members and configured to generate electromagnetic radiation transmitted to heat the tubular members. The heated tubular members can heat the portions of the fluid to break emulsion in the fluid. Upstream the heater, the tool can include a homogenizer operable to mix the fluid to obtain a homogenous fluid and a stabilizer operable to stabilize the fluid to obtain a linear flow. Downstream the heater, the tool can include a separator operable to separate lighter components from heavier components in the fluid after the emulsion breakage.

Abstract: A method to control the shape of an opening in a formation including the steps of emitting a laser beam from a fiber optic cable into a direction unit, focusing the laser beam in the focusing lens to produce a focused laser, collimating the focused beam in the collimating lens to produce a directed beam, directing the directed beam onto a motorized master, where the compact scanner further comprises a motorized slave, wherein the motorized master comprises a master mirror and a master motor, wherein the motorized slave comprises a slave mirror and a slave motor, operating the motorized master and the motorized slave to produce a controlled beam, where the controlled beam moves in a movement pattern, introducing the controlled beam to a laser head, sublimating the formation to produce the opening, and vacuuming the dust and vapor with the vacuum nozzle.

Abstract: A fracturing assembly for forming fractures in a subterranean formation includes a source tool having a rotational joint moveable to orient the source tool in a range of directions and a directional electromagnetic antenna having an electromagnetic wave source. A ceramic-containing member is located within a distance of the electromagnetic antenna to be heated to a fracture temperature by electromagnetic waves produced by the electromagnetic wave source. The ceramic-containing member is positionable to orient a fracture in the subterranean formation at the fracture temperature.

Abstract: A steam injector assembly for handling steam in a subterranean well includes a steam separation system, the steam separation system directing an initial high quality steam to a subterranean formation and directing low quality fluid mix to a heating system. The heating system includes a ceramic-containing member located in a travel path of the low quality fluid mix and an electromagnetic antenna positioned to heat the ceramic-containing member with electromagnetic waves. A relief valve is movable to an open position when an improved high quality steam within a heating chamber of the heating system reaches an injection pressure, wherein in the open position, the relief valve provides a fluid flow path out of the heating chamber.

Abstract: A system for fracturing a formation comprising a laser surface unit configured to generate a laser beam, a power cable electrically connected to a power source, a fluid line connected to a cooling fluid source, a protective shaft extending into the wellbore, the motor configured to rotate a motor shaft, and the thermal shocking tool comprising a protective case, a rotational shaft connected to the motor shaft, the laser delivery device extending from the rotational shaft configured to transform the laser beam to a focused laser beam operable to increase the temperature of the formation to a fracture temperature, and the cooling system extending from the rotational shaft opposite the laser delivery device configured to introduce the cooling fluid stream onto the formation such that the cooling fluid stream reduces the temperature of the formation such that thermal shocks occur and fractures are formed in the formation.

Abstract: A computer system may include a server(s) for storing electronic textbook data and a plurality of computing devices each including a display, a memory, a user input device, and a processor. The processor may display the electronic textbook data on the display, receive comment data from a respective user of the computing device with respect to the electronic textbook data, and provide the comment data to the server(s). The server(s) may be configured to distribute the comment data among the plurality of computing devices. The processor of each computing device may be configured to receive a respective user rating for the distributed comment data and provide the user rating to the server(s). The server(s) may be configured to permanently incorporate given distributed comment data into the electronic textbook data when the user ratings for the given distributed comment data reach a rating threshold.

Abstract: A computing device may include a display, a memory to store electronic textbook data comprising at least one configurable problem to be solved using a given solution technique from among a plurality of different solution techniques, a user input device, and a processor coupled to the display, the memory, and the user input device. The processor may be configured to display the electronic textbook data with the at least one configurable problem on the display, selectively change the given solution technique for the at least one configurable problem based upon the user input device, and display a solution for the at least one configurable problem on the display responsive to the change in the given solution technique.

Abstract: A computing device may include a display, a memory to store electronic textbook data comprising at least one configurable problem to be solved for a system having a plurality of different parameters, a user input device, and a processor coupled to the display, the memory, and the user input device. The processor may be configured to display the electronic textbook data with the at least one configurable problem on the display, selectively change at least one of the parameters of the system to define a new solution for the at least one configurable problem based upon the user input device, and display the new solution on the display.

Abstract: A laser-jet apparatus for creating a penetration through a stress region adjacent to a wellbore includes an outer tool housing, the outer tool housing having a housing central bore. A laser assembly includes a lens case with an outer diameter that is smaller than an inner diameter of the housing central bore, defining an annular passage between the outer tool housing and the lens case. A focusing lens and a collimating lens are located within the lens case. The focusing lens is shaped to control the divergence of a laser beam and the collimating lens is shaped to fix the diameter of the laser beam. A jet fluid path is located in the annular passage, the jet fluid path shaped to merge jet fluid with the laser beam. The outer tool housing has a frusto-conical tip for directing the combined jet fluid and laser beam to the stress region.

Abstract: A system connected to an AC power grid having an AC phase signal includes an inverter module including a first inverter coupled to a DC voltage, actuated based on the AC phase signal. The first inverter provides a first voltage signal having predetermined harmonic components. A second inverter includes second switch elements coupled to the DC voltage and actuated by a second set of control signals phase delayed with respect to the first control signals. A transformer module has first and second primary windings coupled to the first and second inverters. The transformer module further includes a secondary winding coupled to first primary winding, the second primary winding, and the AC power grid. The secondary winding is configured to provide a secondary output voltage to the AC power grid by combining the first voltage signal and the second voltage signal such that the predetermined harmonic components are substantially cancelled.

Abstract: Apparatus and methods for spatially orienting a subterranean pressure pulse to a hydrocarbon-bearing formation are provided. The apparatus includes an injection body with a fixed shape, where the injection body is operable to hold an exothermic reaction component prior to triggering an exothermic reaction of the exothermic reaction component, and where the injection body maintains the fixed shape during and after triggering of the exothermic reaction component. The injection body includes a chemical injection port, where the chemical injection port is operable to feed components of the exothermic reaction component to the injection body. The injection body includes a reinforced plug, where the reinforced plug is operable to direct a pressure pulse generated by the exothermic reaction component within the injection body to a perforation to generate a spatially-oriented fracture, where spatial orientation of the spatially-oriented fracture is pre-determined.

Abstract: A downhole tool, and method of using the downhole tool, for enhancing recovery of heavy oil from a formation. The downhole tool includes an outer core having at least one ceramic portion. At least one electromagnetic antenna is disposed within the outer core. The at least one electromagnetic antenna is operable to emit electromagnetic radiation to heat the at least one ceramic portion.

Abstract: A computer system may include a server(s) for storing electronic textbook data and a plurality of computing devices each including a display, a memory, a user input device, and a processor. The processor may display the electronic textbook data on the display, receive comment data from a respective user of the computing device with respect to the electronic textbook data, and provide the comment data to the server(s). The server(s) may be configured to distribute the comment data among the plurality of computing devices. The processor of each computing device may be configured to receive a respective user rating for the distributed comment data and provide the user rating to the server(s). The server(s) may be configured to permanently incorporate given distributed comment data into the electronic textbook data when the user ratings for the given distributed comment data reach a rating threshold.

Abstract: A power inverter combination includes a half-bridge power inverter including first and second semiconductor power switches receiving input power having an intermediate node therebetween providing an inductor current through an inductor. A controller includes input comparison circuitry receiving the inductor current having outputs coupled to first inputs of pulse width modulation (PWM) generation circuitry, and a predictive control block having an output coupled to second inputs of the PWM generation circuitry. The predictive control block is coupled to receive a measure of Vin and an output voltage at a grid connection point. A memory stores a current control algorithm configured for resetting a PWM period for a switching signal applied to control nodes of the first and second power switch whenever the inductor current reaches a predetermined upper limit or a predetermined lower limit.

Abstract: A power inverter includes a DC/AC inverter having first, second and third phase circuitry coupled to receive power from a power source. A controller is coupled to a driver for each of the first, second and third phase circuitry (control input drivers). The controller includes an associated memory storing a phase skipping control algorithm, wherein the controller is coupled to receive updating information including a power level generated by the power source. The drivers are coupled to control inputs of the first, second and third phase circuitry, where the drivers are configured for receiving phase skipping control signals from the controller and outputting mode selection signals configured to dynamically select an operating mode for the DC/AC inverter from a Normal Control operation and a Phase Skipping Control operation which have different power injection patterns through the first, second and third phase circuitry depending upon the power level.

Abstract: A computing device may include a display, a memory to store electronic book data having a plurality of different content layers each associated with a different content difficulty level, and a processor coupled to the display and the memory. The processor may determine a selected content difficulty level for viewing of the electronic book data, and display on the display the respective content layer of the electronic book data associated with the selected content difficulty level.

Abstract: The present invention is directed to a system configured to be connected to an AC power grid having at least one AC phase signal. The system includes at least one inverter module comprising a first inverter having a plurality of first switch elements coupled to a direct current (DC) voltage and actuated in accordance with a first set of control signals based on the at least one AC phase signal. The first inverter provides a first voltage signal having predetermined harmonic components. The at least one inverter module further comprises a second inverter including a plurality of second switch elements coupled to the DC voltage and actuated in accordance with a second set of control signals phase delayed with respect to the first set of control signals. The second switching inverter providing a second voltage signal having the predetermined harmonic components.

Abstract: A computer system may include a plurality of computing devices each including a display, a memory to store electronic book data comprising at least one configurable problem to be solved, and a processor coupled to the display and the memory. The processor may display the electronic book data with the at least one configurable problem on the display, and apply a changeable seed value to the at least one configurable problem to change an answer associated with the at least one configurable problem.

Abstract: A laser-jet apparatus for creating a penetration through a stress region adjacent to a wellbore includes an outer tool housing, the outer tool housing having a housing central bore. A laser assembly includes a lens case with an outer diameter that is smaller than an inner diameter of the housing central bore, defining an annular passage between the outer tool housing and the lens case. A focusing lens and a collimating lens are located within the lens case. The focusing lens is shaped to control the divergence of a laser beam and the collimating lens is shaped to fix the diameter of the laser beam. A jet fluid path is located in the annular passage, the jet fluid path shaped to merge jet fluid with the laser beam. The outer tool housing has a frusto-conical tip for directing the combined jet fluid and laser beam to the stress region.