1. A device formed of a clamped, micromachined structure, the device comprising:
a piezoelectric material having a top surface and a bottom surface;
a first group of electrodes forming a pattern on the top surface of the first piezoelectric material; and
a second group of electrodes forming the pattern on the bottom surface of the first piezoelectric material.
2. The device of claim 1 wherein the piezoelectric material is a disc.
3. The device of claim 2 wherein the first group of electrodes includes a first electrode having a circular shape centered on the disc.
4. The device of claim 1 wherein the piezoelectric material has a perimeter shape selected from a group consisting of a square and a hexagon.
5. The device of claim 1 wherein the first group of electrodes forms a number of concentric rings separated by a corresponding number of gaps.
6. The device of claim 1 wherein the first group of electrodes includes three or more electrodes.
7. The device of claim 6 further comprising a voltage source configured to drive each one of the three or more electrodes at a substantially different voltage.
8. The device of claim 6 further comprising a voltage source that drives at least two of the three or more electrodes at a substantially equal voltage.
9. The device of claim 8 wherein the substantially equal voltage is about zero Volts.
10. The device of claim 1 further comprising a voltage source configured to differentially drive adjacent ones of the first group of electrodes.
11. The device of claim 1 further comprising a voltage source configured to differentially drive one of the first group of electrodes and an opposing one of the second group of electrodes.
12. The device of claim 1 wherein the piezoelectric material is not initially poled.
13. The device of claim 1 wherein the piezoelectric material is poled Aluminum nitride.
14. The device of claim 1 further comprising a silicon substrate.
15. The device of claim 1 wherein the clamped, micromachined structure includes a support structure.
16. The device of claim 1 wherein the piezoelectric material includes a Lead Zirconate Titanate (PZT).
17. The device of claim 1 wherein the PZT is Perovskite-phase PZT.
18. The device of claim 1 wherein the piezoelectric material includes a piezoelectric ceramic bulk material.
19. The device of claim 1 wherein the clamped, micromachined structure is an ultrasound transducer having a resonant frequency of between one and eighteen Megahertz.
20. The device of claim 1 wherein the first group of electrodes covers about thirty-six percent of a top area of the piezoelectric material.
21. The device of claim 1 wherein the first group of electrodes cover about sixty percent of a radius of the piezoelectric material.
22. The device of claim 1 further comprising:
a second piezoelectric material having a second top surface and a second bottom surface, the second top surface adjacent to the second group of electrodes; and
a third group of electrodes forming the pattern on the second bottom surface of the second piezoelectric material.
23. The device of claim 22 further comprising a voltage source that drives one of the third group of electrodes and a corresponding one of the first group of electrodes at a substantially equal voltage.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of treating a subterranean formation, comprising:
placing a settable composition including an activation device in a wellbore, wherein the activation device is used to increase a setting rate of the settable composition in response to an activation signal; and
transmitting the activation signal to the settable composition to release an activator from the activation device.
2. The method of claim 1, wherein the settable composition sets in a range from one hour to one day after reacting with the activator.
3. The method of claim 1, wherein the activation device includes at least one dimension in a range from about 1 micrometers (\u03bcm) to about 10,000 \u03bcm.
4. The method of claim 1, wherein the signal comprises at least one of an electromagnetic signal, a pressure signal, a magnetic signal, an electric signal, an acoustic signal, an ultrasonic signal, or a radiation signal, and wherein the radiation signal comprises at least one of neutrons, alpha particles, or beta particles.
5. A method of cementing in a subterranean formation, comprising:
placing a cement composition including an activation device in a wellbore, wherein the activation device is configured to release an activator that increases a setting rate of the cement composition; and
transmitting a signal to at least a portion of the cement composition to activate the activation device, wherein the activation device releases the activator in response to at least the signal.
6. The method of claim 5, wherein the activation device is a Micro-Electro-Mechanical System (MEMS) device.
7. The method of claim 5, wherein the activation device mixes with the cement composition at a density in a range from about 4 to about 24 pounds per gallon (ppg).
8. The method of claim 5, wherein the cement composition includes a hydraulic cement, a base fluid and a retarder.
9. The method of claim 5, wherein the cement composition sets in a range from one hour to one day after reacting with the activator.
10. The method of claim 5, wherein the activation device includes at least one dimension in a range from about 1 \u03bcm to about 10,000 \u03bcm.
11. The method of claim 5, wherein the signal comprises at least one of an electromagnetic signal, a pressure signal, a magnetic signal, an electric signal, an acoustic signal, an ultrasonic signal, or a radiation signal, and wherein the radiation signal comprises at least one of neutrons, alpha particles, or beta particles.
12. The method of claim 5, further comprising transmitting a signal through the casing to activate the activation device.
13. An activation device, comprising:
an activation module that encloses an activator that increases a setting rate of a cement composition;
a transducer that receives a wireless activation signal; and
a logic module that transmits a release signal to the activation module to release the activator in response to the transducer receiving the activation signal.
14. The activation device of claim 13, wherein the activation module includes an element enclosing the activator in a reservoir.
15. The activation device of claim 14, wherein the activation signal causes an opening in the element to release the activator.
16. The activation device of claim 15, wherein the opening is based, at least in part, on resistive heating, chemical reaction, or mechanically.
17. The activation device of claim 13, wherein the activator module comprises a microelectrical mechanical system (MEMS) that moves a portion of the activation module to release the activator in response to an activation signal.
18. The activation device of claim 17, wherein the MEMS switches the portion of the activation module between an opened and a closed position at a specified frequency to disperse the activator in the cement composition.
19. The activation device of claim 13, further comprising a power module that powers the logic module.
20. The activation device of claim 13, wherein the activation device mixes with the cement.
21. The activation device of claim 13, wherein the activation module includes at least one dimension in a range from about 1 \u03bcm to about 10,000 \u03bcm.
22. The activation device of claim 13, further comprising a power module that generates a voltage difference between two terminals using an alkaline environment of the cement composition.