摘要:
The present invention provides compositions of treating subterranean zones penetrated by well bores in primary well cementing operations, well completion operations, production stimulation treatments and the like. The invention includes aqueous well treating fluids comprised of water and a water soluble polymer complex fluid loss control additive. Preferred polymer complexes comprise water-soluble polymers made in the presence of hydroxyethylcellulose.
摘要:
The present invention provides methods of treating subterranean zones penetrated by well bores in primary well cementing operations, well completion operations, production stimulation treatments and the like. The methods are basically comprised of introducing into the subterranean zone an aqueous well treating fluid comprised of water and a water soluble polymer complex fluid loss control additive.
摘要:
Coacervate gels having excellent shear viscosities and other properties are made with anionic or cationic polymers, a smaller amount of a surfactant having a charge opposite that of the polymer, and a hydrophobic alcohol. The Zeta Potential of the gel is maintained at an absolute value of at least 20. Optional gel promoting additives include betaines and amine oxides. A preferred gel comprises poly diallyl dimethyl ammonium chloride, a lesser amount of sodium lauryl sulfonate, and lauryl alcohol. The gels are particularly useful in well drilling fluids and well fracturing fluids.
摘要:
Coacervate gels having excellent shear viscosities and other properties are made with anionic or cationic polymers, a smaller amount of a surfactant having a charge opposite that of the polymer, and a hydrophobic alcohol. The Zeta Potential of the gel is maintained at an absolute value of at least 20. Optional gel promoting additives include betaines and amine oxides. A preferred gel comprises poly diallyl dimethyl ammonium chloride, a lesser amount of sodium lauryl sulfonate, and lauryl alcohol. The gels are particularly useful in well drilling fluids and well fracturing fluids.
摘要:
A method of maintaining a constant movement of a cutting blade of an ultrasonic waveguide includes providing an ultrasonic transducer operable to convert a received motional current into a movement of a cutting blade of an ultrasonic waveguide, a measurement circuit connected in a parallel configuration with the ultrasonic transducer, and a variable power source operable to supply current through a set of connection points to the parallel configuration and thereby create the motional current in the ultrasonic transducer. Current is supplied through a set of connection points of the parallel configuration with the variable power source to, thereby, create the motional current in the ultrasonic transducer and the motional current is regulated with a current controller by varying an output of the power source, thereby maintaining a substantially constant rate of movement of the cutting blade across a variety of cutting loads.
摘要:
A surgical stapling instrument includes a handle having a stapler-closing device. A surgical stapling end effector is connected to the handle and has a pair of opposing stapling surfaces. At least one of the stapling surfaces is operable to move with respect to the other of the stapling surfaces upon actuation of the stapler-closing device to apply a compressive force to tissue therebetween. At least one variable member is operable to receive the compressive force applied to the tissue and to exhibit at least one of mechanical and electrical change associated with the received compressive force. The change influences a surgical procedure on the compressed tissue.
摘要:
A modular joint barrier retainer assembly, including: a barrier including one or more material layers; a retainer strip coupled to the barrier; and an anchor flange selectively coupled to the retainer strip at a first end of the anchor flange, wherein a second end of the anchor flange is configured to be selectively coupled to one or more of an expansion joint cover and a building substrate. The barrier is selectively disposed within an expansion joint or other gap of a building. The retainer strip is coupled to the barrier via one or more mechanical fasteners that are disposed through the one or more material layers and secured to the retainer strip. The anchor flange includes a hook portion that selectively engages a lip portion of the retainer strip. The anchor flange is selectively secured to the retainer strip via one or more mechanical fasteners.
摘要:
Embodiments of the present invention include methods and apparatus for dynamically controlling pressure within a wellbore while forming the wellbore. In one aspect, one or more pressure control apparatus are used to maintain desired pressure within the wellbore while drilling the wellbore. In another aspect, pressure is dynamically controlled while drilling using foam to maintain a substantially homogenous foam flow regime within the wellbore annulus for carrying cuttings from the wellbore.
摘要:
An electrically powered surgical instrument includes a surgical end effector having a surgical procedure effecting actuation assembly. A handle is coupled with the end effector. An electric motor is disposed within a shell of the handle and has power terminals and a drive train actuating the assembly when the motor is supplied with power. A break-before-make power supply switch at the handle selectively controls supply of power to the motor. A post-termination braking circuit electrically short-circuits the power terminals when the switch does not supply power to the motor. A method for post-termination braking of an electrical motor utilizes the permanent magnetic field of the motor to counteract an inertia-induced over-stroke characteristic of the motor, drive train, and/or actuation assembly after powered operation by short-circuiting the still-spinning motor to create an electrically generated magnetic field in opposition to the permanent magnetic field upon ceasing supply of power to the motor.
摘要:
A medical device includes a control handle having an articulation joint actuator, a surgical end effector, and a passive articulating joint connecting the end effector to the control handle. The articulation joint actuator, when unactuated, holds the passive articulation joint and, thereby, the end effector, in a substantially fixed articulation position, and, when actuated, releases the passive articulation joint into a freely articulating state to permit free articulation of the end effector with respect to the control handle dependent upon external forces acting upon the end effector. A method for operating the end effector includes retaining the passive articulation joint in a stable position with an articulation lock and actuating a release of the articulation lock to unlock the passive articulation joint and, thereby, permit articulating motion of the end effector through the passive articulation joint dependent upon the external forces acting upon the end effector.