摘要:
A negative contrast agent for MRI is an aqueous suspension having a quantity of barium sulfate between 25 and 30 percent by weight and a quantity of bentonite between 2.5 and 3.5 percent by weight in which a substantial portion of the barium sulfate particles have a mean diameter of at least 10 microns. This negative contrast agent provides dark imaging in a T2 weighted pulse sequence; namely a relative signal intensity (RSI) approaching zero. It also provides a relative signal intensity (RSI) of under 30 percent of that of a reference that approximates tissue in a T1 weighted pulse sequence.
摘要:
An engine control normally effective for regulating the fuel and spark timing to provide substantially optimum engine performance. Periods of heavy operator loading are identified and integrated over time to define engine operating conditions for which engine protection concerns predominate. At such time, the normal controls are overriden to operate the engine at a reduced performance level, thereby to protect the engine from preignition damage.
摘要:
The present invention provides a novel technique for canceling substantially the effects of dispersion when two speed of sound (SOS) measurements are required on the materials within a pipe to perform a calculation or derive certain characteristics about the materials flowing in the pipe. According to some embodiments of the present invention, the apparatus may comprise a signal processor configured to receive signals containing information about two speed of sound measurements having two sets of data related to materials within a pipe; and process the two sets of data simultaneously and determine a ridge point by point difference in order to cancel substantially effects of dispersion.
摘要:
A method and apparatus for measuring at least one parameter of a fluid flowing through an internal passage of an elongated body is provided. The internal passage is disposed between a first wall and a second wall, and the first wall and the second wall each include an interior surface and an exterior surface. The method includes the steps of providing an array of at least two ultrasonic sensor units, operating the sensor units to transmit ultrasonic signals at one or more frequencies substantially coincident with at least one frequency at which the transmitted ultrasonic signals resonate within the first wall, receiving the ultrasonic signals with the sensor units, and processing the received ultrasonic signals to measure the at least one parameter of fluid flow within the internal passage.
摘要:
A method and apparatus for measuring at least one parameter of a fluid flowing through an internal passage of an elongated body is provided. The internal passage is disposed between a first wall and a second wall, and the first wall and the second wall each include an interior surface and an exterior surface. The method includes the steps of providing an array Of at least two ultrasonic sensor units, operating the sensor units to transmit ultrasonic signals at one or more frequencies substantially coincident with at least one frequency at which the transmitted ultrasonic signals resonate within the first wall, receiving the ultrasonic signals with the sensor units, and processing the received ultrasonic signals to measure the at least one parameter of fluid flow within the internal passage.
摘要:
A method, apparatus and system are provided to measure the process flow of a fluid or medium traveling in a pipe. The system and apparatus feature a standoff and piezoelectric-based sensor arrangement having a plurality of standoffs arranged on a pipe and a plurality of sensor bands, each arranged on a respective plurality of standoffs, each having at least one sensor made of piezoelectric material arranged thereon to detect unsteady pressure disturbances in the process flow in the pipe which in turn can be converted to the velocity of and/or speed of sound propagating within the pipe, and a cooling tube arranged in relation to the plurality of standoffs for actively cooling the sensor band; and further comprise a processing module for converting one or more sensor signals into a measurement containing information about the flow of the fluid or medium traveling in the pipe, as well as a pump and heat exchanger for processing the cooling fluid flowing through the cooling tube. The processing includes maintaining the cooling fluid at a desired operating temperature.
摘要:
A switching regulator that has first, second, third and fourth terminals, a first power transistor disposed between the first terminal and a first node, a second power transistor disposed between the first node and a second node, a filter including a capacitor and an inductor, and a controller. The first power transistor is partitioned into a plurality of individually-addressable first transistor segments. The second node couples the second and fourth terminals. The second power transistor is partitioned into a plurality of individually-addressable second transistor segments. The inductor is disposed between the first node and the third terminal, and the capacitor is disposed between the third and fourth terminals. The controller is operable in a plurality of modes including a normal mode in which the controller opens and closes all of the first transistor segments and all of the second transistor segments, and a test mode in which the controller opens and closes less than all of the first transistor segments and all of the second transistor segments.
摘要:
A method of separating two immiscible, melt-viscosity-differing thermoplastic polymer components from a mixed liquid stream thereof forms two discrete and continuous phases having a sheath/core configuration, wherein the sheath substantially contains the polymer component with the higher melt viscosity and the core substantially contains the polymer component with the lower melt viscosity. The mixed liquid stream contains a predominant amount (i.e., greater than 50% by volume) of the higher viscosity polymer component and a minority amount (i.e., less than 50% by volume) of the lower viscosity polymer component. The method involves directing the stream through a shear zone at a shear temperature and a shear rate sufficient to form the two discrete and continuous phases, the first of which substantially contains the lower viscosity polymer component and the second of which substantially contains the higher viscosity polymer component.