Abstract: Automated device discovery of pairing-eligible devices for authenticating an unidentified user of a computing device is provided. When the user initiates a login on the computing device on which the user's identity is not known, an automated pairing-eligible device discovery authentication system interrogates a resource (e.g., subnetwork router, calendaring server) for identifying pairing-eligible devices that may be used as a second factor for authentication. A list of the pairing-eligible devices is presented to the user on the computing device. Upon selection of a pairing-eligible device to use as a second factor to verify the user's identity, the user's identity is determined, and a notification is sent to the selected pairing-eligible device for enabling the user to verify his/her identity using a second factor. Upon completion of an authentication challenge on the selected pairing-eligible device, authentication of the user is completed, and a signed token is sent to the computing device.

Abstract: Embodiments are directed to revoking user sessions using signaling. In one scenario, an identity platform operating on a computer system receives an indication indicating that a user's login account has been compromised, where the user's login account has an associated login session and corresponding session artifact that is valid for a specified amount of time. The identity platform generates a signal indicating that the login session is no longer trusted and that the user is to be re-directed to the identity platform to re-authenticate and renew the session artifact and provides the generated signal to various relying parties including at least one relying party that is hosting the login session for the user.

Abstract: Embodiments are directed to revoking user sessions using signaling. In one scenario, an identity platform operating on a computer system receives an indication indicating that a user's login account has been compromised, where the user's login account has an associated login session and corresponding session artifact that is valid for a specified amount of time. The identity platform generates a signal indicating that the login session is no longer trusted and that the user is to be re-directed to the identity platform to re-authenticate and renew the session artifact and provides the generated signal to various relying parties including at least one relying party that is hosting the login session for the user.

Abstract: A two-stroke engine includes a crankcase defining a cylinder bore, a piston moveably disposed within the cylinder bore, and a cylinder head that covers the cylinder bore. A wall surface of the cylinder bore, a piston combustion surface of the piston, and a head combustion surface of the cylinder head, cooperate to define a combustion chamber for combusting a fuel therein. A thermal conductivity reducing mechanism is disposed in thermal connectivity with at least one of the crankcase, the piston, and the cylinder head for reducing heat transfer from combusted fuel within the combustion chamber to at least one of the crankcase, the piston, and the cylinder head. The thermal conductivity reducing mechanism may include a layer of low conductivity material coating one of the surfaces defining the combustion chamber, or a void in the cylinder head and/or the crankcase adjacent the combustion chamber.

Abstract: Embodiments are directed to revoking user sessions using signaling. In one scenario, an identity platform operating on a computer system receives an indication indicating that a user's login account has been compromised, where the user's login account has an associated login session and corresponding session artifact that is valid for a specified amount of time. The identity platform generates a signal indicating that the login session is no longer trusted and that the user is to be re-directed to the identity platform to re-authenticate and renew the session artifact and provides the generated signal to various relying parties including at least one relying party that is hosting the login session for the user.

Abstract: A free piston linear alternator including a pair of pistons, each piston axially opposed from the other and generating electric current when linearly translating within the cylinder, a combustion chamber disposed between the pistons, a return mechanism configured to return the pistons to respective first positions from respective second positions after combustion; and an exhaust system fluidly coupled to the combustion chamber and including a power turbine transforming exhaust gas feedstream pressure into a mechanical output.

Abstract: A free piston linear alternator includes a cylinder having a pair of outer chambers, a pair of opposed pistons and a combustion chamber disposed between the opposed pistons. Each outer chamber is disposed between respective ones of the pistons and a respective outer end of the cylinder. The pistons are axially opposed from each other and independently generate electric current when each of the pistons linearly translate. Each of a pair of return members is disposed within a respective one of the outer chambers, and each of the return members is configured to return respective ones of the pistons to a respective first position from a respective second position after combustion.

Abstract: An internal combustion engine has four cylinders, each having a respective piston positioned therein and connected with a crankshaft for movement in the respective cylinder. Each cylinder has a plurality of ports with a plurality of valves openable and closable to control fluid flow into and out of the cylinder through the ports. Combustion occurs in a first two of the four cylinders (power cylinders) that are each interconnected between a second two of the four cylinders (inductor cylinders) via passages connecting ports of the respective cylinders. Opening and closing of the valves is timed to accomplish internal exhaust gas recirculation, i.e., such that fluid directed from the power cylinders to the inductor cylinders via the passages after combustion is redirected via the passages from the inductor cylinders to the power cylinders. A method of internal exhaust gas recirculation for an engine as described above is also provided.

Abstract: A free piston linear alternator includes a cylinder having a pair of bounce chambers, a pair of scavenging chambers, a pair of opposed pistons and a combustion chamber disposed between the opposed pistons. The pistons are axially opposed from each other and generate electric current when each of the pistons linearly translate. Each of the bounce chambers is disposed between respective ones of the pistons and a respective outer end of the cylinder and includes substantially constrained air configured to return respective ones of the pistons to a respective first position from a respective second position after combustion.

Abstract: An internal combustion engine has a first work extraction station for extracting work from combustion and expansion of working gases. An emission treatment station treats the working gases after leaving the first extraction work station for reducing emissions. A second work extraction station receives the working gases from the emission treatment station for a second extraction of work from the working gases.

Abstract: An internal combustion engine includes a compressor cylinder having a respective inlet, a first outlet and a respective piston slideably movable within the compressor cylinder and operatively connected to a rotating crankshaft. The compressor cylinder provides a first stage of compression to a charge when the charge is transferred from the compressor cylinder during every revolution of the crankshaft. A first power cylinder includes a respective inlet in fluid communication with the first outlet of the compressor cylinder, a respective outlet and a respective piston slideably movable within the first power cylinder and operatively connected to the rotating crankshaft. The first power cylinder provides a second stage of compression and firing of the charge within the first power cylinder every two revolutions of the crankshaft.

Abstract: Engines and processes for their operation include a compressor cylinder, at least one power cylinder, and an expander cylinder. The outlet of the compressor cylinder is fed to the inlet of a power cylinder, and the outlet of the power cylinder is fed to the expander cylinder. The compressor cylinder and the expander cylinder are operated in two-stroke fashion, and the power cylinder is operated in four-stroke fashion, all of which cylinders share a common crankshaft. Heat may be recuperated from the exhaust gas and directed to the inlet gas of the power cylinder, increasing overall efficiency.

Abstract: An internal combustion engine has a first work extraction station for extracting work from combustion and expansion of working gases. An emission treatment station treats the working gases after leaving the first extraction work station for reducing emissions. A second work extraction station receives the working gases from the emission treatment station for a second extraction of work from the working gases.

Abstract: A free piston linear alternator including a pair of pistons, each piston axially opposed from the other and generating electric current when linearly translating within the cylinder, a combustion chamber disposed between the pistons, a return mechanism configured to return the pistons to respective first positions from respective second positions after combustion; and an exhaust system fluidly coupled to the combustion chamber and including a power turbine transforming exhaust gas feedstream pressure into a mechanical output.

Abstract: A free piston linear alternator includes a cylinder having a pair of bounce chambers, a pair of scavenging chambers, a pair of opposed pistons and a combustion chamber disposed between the opposed pistons. The pistons are axially opposed from each other and generate electric current when each of the pistons linearly translate. Each of the bounce chambers is disposed between respective ones of the pistons and a respective outer end of the cylinder and includes substantially constrained air configured to return respective ones of the pistons to a respective first position from a respective second position after combustion.

Abstract: A free piston linear alternator includes a cylinder having a pair of outer chambers, a pair of opposed pistons and a combustion chamber disposed between the opposed pistons. Each outer chamber is disposed between respective ones of the pistons and a respective outer end of the cylinder. The pistons are axially opposed from each other and independently generate electric current when each of the pistons linearly translate. Each of a pair of return members is disposed within a respective one of the outer chambers, and each of the return members is configured to return respective ones of the pistons to a respective first position from a respective second position after combustion.

Abstract: An internal combustion engine has four cylinders, each having a respective piston positioned therein and connected with a crankshaft for movement in the respective cylinder. Each cylinder has a plurality of ports with a plurality of valves openable and closable to control fluid flow into and out of the cylinder through the ports. Combustion occurs in a first two of the four cylinders (power cylinders) that are each interconnected between a second two of the four cylinders (inductor cylinders) via passages connecting ports of the respective cylinders. Opening and closing of the valves is timed to accomplish internal exhaust gas recirculation, i.e., such that fluid directed from the power cylinders to the inductor cylinders via the passages after combustion is redirected via the passages from the inductor cylinders to the power cylinders. A method of internal exhaust gas recirculation for an engine as described above is also provided.

Abstract: Engines and processes for their operation include a compressor cylinder, at least one power cylinder, and an expander cylinder. The outlet of the compressor cylinder is fed to the inlet of a power cylinder, and the outlet of the power cylinder is fed to the expander cylinder. The compressor cylinder and the expander cylinder are operated in two-stroke fashion, and the power cylinder is operated in four-stroke fashion, all of which cylinders share a common crankshaft. Heat may be recuperated from the exhaust gas and directed to the inlet gas of the power cylinder, increasing overall efficiency.