Abstract: Techniques are described for communications in an L2 virtual network. In an example, the L2 virtual network includes a plurality of L2 compute instances hosted on a set of host machines and a plurality of L2 virtual network interfaces and L2 virtual switches hosted on a set of network virtualization devices. An L2 virtual network interface emulates an L2 port of the L2 virtual network. Access control list (ACL) information applicable to the L2 port is sent to a network virtualization device that hosts the L2 virtual network interface.

Abstract: Systems and methods for a VLAN switching and routing service (VSRS) are disclosed herein. A method can include generating a table for an instance of a VSRS, which VSRS couples a first virtual layer 2 network (VLAN) with a second network. The table can contain information identifying IP addresses, MAC addresses, and virtual interface identifiers for instances within the virtual layer 2 network. The method can include receiving with the VSRS a packet from a first instance designated for delivery to a second instance within the virtual layer 2 network, identifying with the VSRS the second instance within the virtual layer 2 network for delivery of the packet based on information received with the packet and information contained within the table, and delivering the packet to the identified second instance.

Abstract: A pulse modulated oxygen dispensing and pressurization system provides a variable range of controlled oxygen bolus to an enclosed breathing environment supporting and maintaining required pressure conditions in accordance with desired flow demand. As oxygen is consumed by the user from within the enclosed breathing environment, the exhaled gases and moisture are conditioned or vented to acceptable levels by additional systems associated with the environment. These additional systems cause an ongoing need to replenish the oxygen within the environment and maintain the required partial pressure of oxygen. Specific to one of a plurality of modes of operation, the system responds to changes in regulated output pressure by delivering a precisely metered periodic bolus volume of oxygen to support a requirement of the environment volume. The bolus is variable based on a plurality of factors to increase and decrease changes in rates of flow required to maintain regulated pressure.

Abstract: An environmental control system for a space vehicle includes an oxygen supply, a nitrogen supply, a first pressure control panel having a first oxygen control board configured to receive an oxygen gas from the oxygen supply and a first nitrogen control board configured to receive a nitrogen gas from the nitrogen supply, and a supervisory controller configured to control the first pressure control panel and thereby to adjust a partial pressure of oxygen and an ambient pressure of an oxygen/nitrogen gas mixture within a first module.

Abstract: A pulse modulated oxygen dispensing and pressurization system provides a variable range of controlled oxygen bolus to an enclosed breathing environment supporting and maintaining required pressure conditions in accordance with desired flow demand. As oxygen is consumed by the user from within the enclosed breathing environment, the exhaled gases and moisture are conditioned or vented to acceptable levels by additional systems associated with the environment. These additional systems cause an ongoing need to replenish the oxygen within the environment and maintain the required partial pressure of oxygen. Specific to one of a plurality of modes of operation, the system responds to changes in regulated output pressure by delivering a precisely metered periodic bolus volume of oxygen to support a requirement of the environment volume. The bolus is variable based on a plurality of factors to increase and decrease changes in rates of flow required to maintain regulated pressure.

Abstract: A roller cone drill bit for drilling earth formation includes rows arranged on each of the cones such that, when viewed in routed profile, cutting element profiles partially overlap other cutting element profiles. The roller cone drill bit having at least a first three interior rows adjacent a gage row, each have a cutting element count selected from the group of 16, 18, 21 and 26 cutting elements.

Abstract: A rolling cone drill bit comprises a plurality of bottomhole cutter elements positioned in a first circumferential row, wherein at least one of the cutter elements comprises a cutting portion extending from a base portion to a point furthermost from the base portion, defining an extension height. The ratio of the cross-sectional area of the cutter element at a point equal to ninety-four percent of the extension height to the cross-sectional area of the cutter element base is greater than 0.2. Moreover, the ratio of the extension height to the base diameter is not greater than 0.75.

Abstract: A drill bit for drilling through earthen formations and forming a borehole. In an embodiment, the bit comprises a bit body having a bit axis. In addition, the bit comprises a plurality of cone cutters, each of the cone cutters being mounted on the bit body and adapted for rotation about a different cone axis. Further, at least one cone cutter on the bit comprises an array of cutter elements mounted in a band. Still further, the cutter elements in the array are mounted in a plurality of differing radial positions relative to the bit axis.

Abstract: A rolling cone drill bit includes at least one cutter element comprising a base portion and a cutting portion extending from the base portion. The cutting portion includes a cutting surface with an apex defining an extension height and at least one rib extending from the apex toward the base portion. In addition, the at least one rib has a convex outer surface in profile view.

Abstract: A roller cone drill bit for drilling earth formation may include rows arranged on each of the cones such that when viewed in routed profile, cutting element profiles partially overlap with other cutting element profiles and at least the first three interior rows adjacent a gage row each have a cutting element count selected from the group of 16, 18, 21 and 26 cutting elements.

Abstract: A rolling cone drill bit includes at least one cutter element comprising a base portion and a cutting portion extending from the base portion. The cutting portion includes a cutting surface with an apex defining an extension height and at least one rib extending from the apex toward the base portion. In addition, the at least one rib has a convex outer surface in profile view.

Abstract: A drill bit includes a plurality of cutting elements are positioned on the at least two roller cones, wherein cutting elements contributing to an operative gage row of the drill bit comprise less than 31 percent of a total cutting elements of the drill bit that contact the bottom of the borehole. A method to design a roller cone drill bit includes designing an initial bit, testing the initial bit; and adjusting the bit design to optimize at least one of rate of penetration and wear resistance, wherein cutting elements contributing to an operative gage row of the adjusted bit design comprise less than 31 percent of a total of cutting elements on the adjusted bit design that contact a bottom of a borehole.

Abstract: A drill bit for drilling through earthen formations and forming a borehole. In an embodiment, the bit comprises a bit body having a bit axis. In addition, the bit comprises a plurality of cone cutters, each of the cone cutters being mounted on the bit body and adapted for rotation about a different cone axis. Further, at least one cone cutter on the bit comprises an array of cutter elements mounted in a band. Still further, the cutter elements in the array are mounted in a plurality of differing radial positions relative to the bit axis.

Abstract: A rolling cone drill bit comprises a plurality of bottomhole cutter elements positioned in a first circumferential row, wherein at least one of the cutter elements comprises a cutting portion extending from a base portion to a point furthermost from the base portion, defining an extension height. The ratio of the cross-sectional area of the cutter element at a point equal to ninety-four percent of the extension height to the cross-sectional area of the cutter element base is greater than 0.2. Moreover, the ratio of the extension height to the base diameter is not greater than 0.75.