Abstract: Systems and methods are provided for efficiently maintaining a transaction sequence witness service to ensure that requests to read data provide consistent results across all storage nodes in a distributed system. Each storage node that stores data in response to a particular update event may first update the transaction sequence witness service with the sequence number for the update event. Thus, any other storage node that services a subsequent request for the data will be able to see, via the transaction sequence witness service, the sequence number that must be available on the storage node to respond to the request.

Abstract: Systems and methods are provided for efficiently maintaining a transaction sequence witness service to ensure that requests to read data provide consistent results across all storage nodes in a distributed system. When a storage node receives a request for a data object, the node may obtain—from transaction sequence witness service—the latest sequence number associated with the object. If the sequence number indicates the object has been modified in the period of time since the currently stored version was stored, the node can obtain the current version from persistent storage.

Abstract: Systems and methods are provided for managing data partitions in a distributed storage system and, in particular, the routing data used by the distributed storage system to route requests to the proper caching layers, persistent storage nodes, etc. Data items may be managed in a multi-tier configuration in which they are grouped into different partitions based on their key prefixes, and partitions are grouped into different cells based on key ranges. When partitions are moved from cell-to-cell, or when cells are split, the routing data is changed accordingly. In order to ensure that the correct routing data is used throughout the distributed storage system, a change to routing data may be accompanied by a special barrier record being written to the transaction log of affected partitions.

Abstract: Systems and methods are provided for managing the order of data written to a transaction log in a distributed storage system. In a system with multiple nodes, if sequencers are naively generated without taking into consideration inconsistencies among the different nodes generating the sequencers, then the sequencers may not increase for each data transaction. To alleviate this problem, the node committing the transaction to the transaction log may perform a consistent read and verifies that the sequencer advances. If the sequencer does not advance, the node can perform a context-dependent operation such as adjusting the sequencer, acknowledging the write without committing it to the transaction log, or rejecting the write altogether.

Abstract: Systems and methods are provided for using a distributed cache architecture with different methods to load balance requests depending upon whether a requested data item is a freely-requested item (e.g., a “hot key”). The cache may be implemented as a consistent hash ring, and most keys may be assigned to particular node based on a consistent hash. For hot key requests, the requests may be distributed among a subset of nodes rather than being assigned to a specific node using consistent hashing. When a witness service is used to ensure that cached data is fresh, verification requests for data regarding hot keys may be batched to avoid overloading the witness service with hot key requests.

Abstract: In a particular implementation, an electric power device includes a body, a receptacle configured to receive a plug, and a source connector configured to be coupled to a power source. The electric power device further includes a casing coupled to the body and movable with respect to the body between a first position in which the casing defines an enclosed chamber and access to the receptacle is inhibited and a second position in which the casing is configurable to enable access to the receptacle for receipt of the plug. A transition from the first position to the second position is configured to cause the receptacle to be electrically decoupled from the source connector when the casing is at the second position, and a transition from the second position to the first position is configured to cause the receptacle to be electrically coupled to the source connector when the casing is at the first position.

Abstract: In a particular implementation, an electric power device includes a body, a receptacle configured to receive a plug, and a source connector configured to be coupled to a power source. The electric power device further includes a casing coupled to the body and movable with respect to the body between a first position in which the casing defines an enclosed chamber and access to the receptacle is inhibited and a second position in which the casing is configurable to enable access to the receptacle for receipt of the plug. A transition from the first position to the second position is configured to cause the receptacle to be electrically decoupled from the source connector when the casing is at the second position, and a transition from the second position to the first position is configured to cause the receptacle to be electrically coupled to the source connector when the casing is at the first position.

Abstract: A reinforced paper includes a nonwoven fibrous mat impregnated with a polyetherimide composition. The nonwoven fibrous mat includes a reinforcing fiber, a high strength toughening fiber, or a combination thereof. The polyetherimide composition includes a polyetherimide having repeating units as defined herein. A method of making a reinforced paper is also disclosed. The method includes contacting at least a portion of a nonwoven fibrous mat with a composition to form a pre-preg, and heating under conditions effective to provide the reinforced paper. Articles including the reinforced paper are also described.

Abstract: A support arm (12) includes: a body portion disposed between a seat end (20) and a table end (18); wherein the support arm (12) comprises a composition comprising a polymeric material, a metallic material, a thermoset material, an elastomeric material, or a combination comprising at least one of the foregoing, and a filler; and wherein the seat end (20) comprises a snap fit connector (14) configured to engage with an opening (22) in the seat end (20).

Abstract: A method of forming a three dimensional object comprising: depositing a layer of thermoplastic polymeric material in a preset pattern on a platform to form a deposited layer; directing an energy source, via an energy beam at an energy source target area on the deposited layer to increase the surface energy of the deposited layer at the energy source target area; contacting the energy source target area with a subsequent layer wherein the subsequent layer is deposited along a path of the preset pattern; wherein directing an energy source at the energy source target area comprises applying energy to the layer at an area preceding the depositing of the subsequent layer to that area; and repeating the preceding steps to form the three dimensional object.

Abstract: Disclosed herein are polycarbonate fibers and fibrous substrates, such as papers, containing such fibers. The polycarbonate fibers are produced from a polymeric composition comprising a cross-linkable polycarbonate containing endgroups derived from a monofunctional benzophenone or containing repeating units derived from a difunctional benzophenone. The polycarbonate fibers can be combined with other fibers to form the fibrous substrate. Upon exposure to ultraviolet light, crosslinking of the polycarbonate fibers will occur, improving various properties of the fibrous substrate.

Abstract: A method comprises preparing or receiving a polyetherimide precursor solution including (i) a solvent comprising water, aliphatic alcohol, or a mixture thereof; (ii) an amine additive comprising a secondary or tertiary amine; and (iii) a polyetherimide precursor dissolved and dissociated in the solvent. The method further comprises at least partially coating or impregnating one or more reinforcement structures with the polyetherimide precursor solution and polymerizing the one or more polyetherimide precursor reagents to form a polyetherimide matrix such that the one or more reinforcement structures are at least partially embedded in the polyetherimide matrix to provide a composite article.

Abstract: A method of forming a three dimensional object comprising: depositing a layer of thermoplastic polymeric material in a preset pattern on a platform (14) to form a deposited layer (50); directing an energy source (54), via an energy beam at an energy source target area (56) on the deposited layer (50) to increase the surface energy of the deposited layer at the energy source target area; contacting the energy source target area (56) with a subsequent layer (52) wherein the subsequent layer (52) is deposited along a path of the preset pattern; wherein directing an energy source (54) at the energy source target area (56) comprises applying energy to the layer at an area preceding the depositing of the subsequent layer to that area; and repeating the preceding steps to form the three dimensional object.

Abstract: A method to form a part can comprise forming a pattern with a commingled yarn (10), wherein the commingled yarn comprises thermoplastic resin filaments (40) formed from a thermoplastic material and reinforcing filaments (20) formed from a reinforcing material, and wherein the reinforcing material has a glass transition temperature and/or a decomposition temperature that is higher than a glass transition temperature of the thermoplastic material; attaching the pattern to a carrier material (76) to form a preform (70); and using the preform to form a part.

Abstract: Disclosed herein are polycarbonate fibers and fibrous substrates, such as papers, containing such fibers. The polycarbonate fibers are produced from a polymeric composition comprising a cross-linkable polycarbonate containing endgroups derived from a monofunctional benzophenone or containing repeating units derived from a difunctional benzophenone. The polycarbonate fibers can be combined with other fibers to form the fibrous substrate. Upon exposure to ultraviolet light, crosslinking of the polycarbonate fibers will occur, improving various properties of the fibrous substrate.

Abstract: A composition for the manufacture of a porous, compressible article, the composition comprising a combination of: a plurality of reinforcing fibers; a plurality of thermoplastic fibers; optionally a plurality of polymeric binder fibers; and continuous spaced carrier fibers; wherein the polymeric binder fibers have a melting point lower than the thermoplastic fibers; methods for forming the porous, compressible article; and articles containing the porous, compressible article. An article comprising a thermoformed composite is also disclosed, wherein the composite is not supported by a scrim layer and the composite exhibits improved conformation to fine mold details to which the scrim layer could not accurately conform.

Abstract: An molding apparatus useful for molding polymer compositions includes a substrate; a first insulating layer having an electrical resistivity of at least about 1010 ohm-centimeters and thermal conductivity of about 0.2 to about 5 watts/(meter-kelvin); a heating element; a second insulating layer having an electrical resistivity of at least about 1010 ohm-centimeters and a thermal conductivity of at least about 5 watts/(meter-kelvin); and a first molding layer having a specific heat capacity of about 100 to about 2,500 joules/(kilogram-kelvin), and optionally, a second molding layer. The apparatus provides rapid heating and cooling of the mold surface. The apparatus may be employed for rapidly molding articles having desirable surface characteristics.

Abstract: An molding apparatus useful for molding polymer compositions includes a substrate; a first insulating layer having an electrical resistivity of at least about 1010 ohm-centimeters and thermal conductivity of about 0.2 to about 5 watts/(meter-kelvin); a heating element; a second insulating layer having an electrical resistivity of at least about 1010 ohm-centimeters and a thermal conductivity of at least about 5 watts/(meter-kelvin); and a first molding layer having a specific heat capacity of about 100 to about 2,500 joules/(kilogram-kelvin), and optionally, a second molding layer. The apparatus provides rapid heating and cooling of the mold surface. The apparatus may be employed for rapidly molding articles having desirable surface characteristics.