Abstract: Generally described, one or more aspects of the present application relate to a public snapshot service for creating and managing block-level snapshots. For example, the public snapshot service can create a snapshot based on (i) a specification of a parent snapshot to be used as a basis for a given snapshot, and (ii) a specification of the data blocks to be backed up in the given snapshot. The data blocks in the snapshot may be stored in a specific storage path structure that facilitates computation of a block difference with respect to the parent snapshot.

Abstract: Techniques are described for allocating computing resources to customers of a multi-tenant web services platform. Computing capacity capable of running a computing instance is allocated to a customer. The computing capacity includes storage capacity that is disassociated from the allocated computing capacity when the allocated computing capacity is de-allocated from the customer. An indication that a virtual storage resource should be associated with the allocated computing capacity is received. The virtual storage resource is persisted independent of the allocation of the computing capacity to the customer. The storage capacity and the virtual storage resource are configured to synchronize data stored thereon while maintaining the storage capacity as an attached storage volume for the computing instance.

Abstract: Embodiments are disclosed for launching a virtual machine and then configuring the virtual machine after launch. Metadata configuration information can be stored in conjunction with virtual machine image configuration data. The virtual machine image configuration data can be used to launch a virtual machine. The metadata configuration information can then be used to further configure the virtual machine after launch. Both the metadata configuration information and the virtual machine image configuration data can be stored in the same virtual machine registration record.

Abstract: Embodiments are disclosed for launching a virtual machine and then configuring the virtual machine after launch. Metadata configuration information can be stored in conjunction with virtual machine image configuration data. The virtual machine image configuration data can be used to launch a virtual machine. The metadata configuration information can then be used to further configure the virtual machine after launch. Both the metadata configuration information and the virtual machine image configuration data can be stored in the same virtual machine registration record.

Abstract: Techniques are disclosed for a client-and-server architecture where the client makes asynchronous API calls to the client. Where the client makes multiple asynchronous API calls, and where these API calls have dependencies (i.e., a result of one call is used as a parameter in a second call), the client may send the server these multiple asynchronous API calls before execution of a call has completed. The server may then execute these multiple asynchronous API calls, using a result generated from one call as a parameter to another call.

Abstract: Techniques are disclosed for a client-and-server architecture where the client makes deferred API calls to the server. The server may receive such a deferred API call, and evaluate whether the call will be executed at the future time specified in the call. The server may use a model of tasks already scheduled to be performed at the future time, or projected to be performed at the future time, and compare those tasks against a projected capacity at the future time. Where there will be sufficient capacity, the server may execute process the deferred API call at the future time, and where there will not be sufficient capacity, the server may inform the client that the call will not be processed at the future time.

Abstract: A process for preparing a catalyst comprising (A) selecting a catalyst support selected from the group consisting of gels of silica, silica alumina, alumina, aluminum phosphate, aluminaphospate, and combinations of two or more thereof; (B) mixing the catalyst support with one or more chromium containing compound, wherein the chromium containing compound is selected from the group consisting of chromium containing compounds which are oxidizable to a Cr+6 state and chromium containing compounds wherein the chromium is in a Cr+6 state; (C) mixing the catalyst support with one or more transition metal catalyst component; (D) calcining the catalyst support; and (E) optionally for the chromium containing compound which is oxidizable to a Cr+6 state, converting the chromium in the chromium containing compound to Cr+6; and (F) spray drying the catalyst support to form catalyst particles; wherein steps (B)-(F) may occur separately in any order or wherein any one or more of steps (B)-(F) may be combined together; and w

Abstract: The invention provides an ethylene-based interpolymer comprising the following features: a) density from 0.910 to 0.930 g/cc; b) melt index (I2) from 0.1 to 0.5 g/10 min; and c) a high density fraction in an ATREF short chain branch distribution (SCBD) curve, eluting above 92° C., of greater than 10 percent to less than 28 percent of the total ATREF SCBD curve area. The invention also provides a composition comprising an ethylene-based interpolymer that comprises the following features: a) a density from 0.919 to 0.928 g/cc; b) a melt index (I2) from 0.1 to 0.8 g/10 min; and c) a high density fraction in an ATREF short chain branch distribution (SCBD) curve, eluting above 92° C., of greater than 10 percent to less than 28 percent of the total ATREF SCBD curve area. The invention also provides a hollow tube comprising at least one component formed from a composition comprising an ethylene-based interpolymer that comprises the following features: a) a density from 0.919 to 0.

Abstract: A process for preparing a catalyst, and catalysts prepared thereby. The process includes selecting a catalyst support and mixing it with one or more chromium containing compounds oxidizable to a Cr+6 state or already in a Cr+6 state, and with one or more transition metal catalyst component, and calcining the catalyst support while oxidizing any chromium containing compound to a Cr+6 state, and spray drying the catalyst support to form catalyst particles. The catalyst supports are characterized by a surface area greater than 50 m2/gram and a pore volume greater than 0.5 cc/gram at the time of mixing the catalyst support with the chromium containing compound.

Abstract: A process for preparing a catalyst, and catalysts prepared thereby. The process includes selecting a catalyst support and mixing it with one or more chromium containing compounds oxidizable to a Cr+6 state or already in a Cr+6 state, and with with one or more transition metal catalyst component, and calcining the catalyst support while oxidizing any chromium containing compound to a Cr+6 state, and spray drying the catalyst support to form catalyst particles. The catalyst supports are characterized by a surface area greater than 50 m2/gram and a pore volume greater than 0.5 cc/gram at the time of mixing the catalyst support gels with the chromium containing compound.

Abstract: A payload door and elevator system for the translation of a payload such as a camera, from a stowed position within an aircraft fuselage to a deployed position projecting through an aperture formed in the wall of the fuselage. The system employs a translation component engaged to vertically translate the payload and operatively positioned inline with the aperture. Payload doors sealing the aperture horizontally translate in opposing directions once vertically translated from sealed engagement with the aperture. The horizontal translation alleviates much of the stress imparted to doors on aircraft which move to vertical positions in or extending from the aperture in the fuselage.

Abstract: A spray-dried composition comprising the reaction product of a magnesium halide, a solvent, an electron donor compound, and a transition metal compound and an inert filler comprising substantially spherical particles having an average particle size ranging from about 1 ?m to about 12 ?m, and a polymerization process using the same.

Abstract: A spray-dried catalyst precursor composition and method of making a spray-dried catalyst precursor composition with an inert filler, magnesium, a transition metal, solvent, and one electron donor compound. The catalyst precursor composition is substantially free of other electron donor compounds, the molar ratio of the electron donor compound to magnesium is less than or equal to 1.9, and comprises spherical or substantially spherical particles having a particle size of from about 10 to about 200 ?m. Catalysts made from the spray-dried catalyst precursors and polymerization methods using such catalysts are disclosed.

Abstract: A spray-dried composition comprising the reaction product of a magnesium halide, a solvent, an electron donor compound, and a transition metal compound and an inert filler comprising substantially spherical particles having an average particle size ranging from about 1 &mgr;m to about 12 &mgr;m, and a polymerization process using the same.

Abstract: A method of making a spray-dried composition using a solution or mixture comprising the reaction product of a magnesium halide, a solvent, an electron donor compound, and a transition metal compound and an inert filler comprising substantially spherical particles having an average particle size ranging from 1 &mgr;m to about 12 &mgr;m.

Abstract: A magnesium halide composition comprising and/or made from a magnesium halide, a solvent suitable for an electron donor compound and an electron donor compound. The composition is characterized by enhanced solubility whereby it has a solubility in the solvent that does not decrease as a function of temperature up to the boiling point of the solvent and the solubility of the magnesium halide in the solvent is greater than 0.7 mol/liter. A polymerization catalyst precursor composition can be made from magnesium halide composition by mixing the magnesium halide composition with a transition metal compound.

Abstract: A method for increasing the solubility of a magnesium halide includes providing an electron donating solvent, contacting a magnesium halide with the solvent; and providing an electron donor compound to form a magnesium halide composition. The composition is characterized by a solubility in the electron donor solvent that does not decrease up to the boiling point of the solvent. A polymerization catalyst precursor composition comprises the product of mixing the magnesium halide composition with a transition metal compound. Active catalysts prepared from such precursors and a methods of polymerization using such catalysts are also disclosed.

Abstract: A spray-dried catalyst precursor composition and method of making a spray-dried catalyst precursor composition with an inert filler, magnesium, a transition metal, solvent, and one electron donor compound. The catalyst precursor composition is substantially free of other electron donor compounds, the molar ratio of the electron donor compound to magnesium is less than or equal to 1.9, and comprises spherical or substantially spherical particles having a particle size of from about 10 to about 200 &mgr;m. Catalysts made from the spray-dried catalyst precursors and polymerization methods using such catalysts are disclosed.

Abstract: A spray-dried composition comprising an inert porous filler and a reaction product of 1) a mixture or reaction product of a magnesium halide, a solvent, an electron donor compound, and a transition metal compound. The filler is substantially spherical and has an average particle size ranging from about 1 &mgr;m to about 12 &mgr;m. Methods of making spray-dried compositions, catalysts and polymerization processes employing such are also described.

Abstract: A process of polymerizing ethylene or ethylene and one or more comonomers in one or more fluidized bed reactors with a catalyst system comprising (i) a supported or unsupported magnesium/titanium based precursor in slurry form, said precursor containing an electron donor; and (ii) an activator containing aluminum in an amount sufficient to essentially complete the activation of the precursor is disclosed. In the process, the precursor and the activator are mixed prior to introduction into the reactor in at least one mixing procedure, and then the mixture is contacted again with additional activator to essentially complete activation of the precursor. In the method, the atomic ratio of aluminum to titanium is in the range of about 1:1 to about 15:1 and the mole ratio of activator to electron donor is about 1:1 to about 2:1, and no additional activator is introduced into the reactor(s).