Author: claimsbot

1. A method of feeding an antenna comprising:
propagating a signal in one or more waveguides, the signal propagating in multiple modes;
coupling the one or more waveguides to the antenna; and
controlling a propagation characteristic of the respective modes, relative to each other, to steer an electromagnetic beam of the antenna.
2. The method as recited in claim 1 wherein the signal is propagating in multiple modes in a common waveguide.
3. The method as recited in claim 1 further comprising:
generating the signal at a transmitter;
splitting the signal to enable propagation of the signal along two or more paths in respective modes;
controlling the propagation characteristic in at least one of the paths; and
coupling the two or more paths to the one or more waveguides.
4. The method as recited in claim 1 further comprising:
coupling two or more paths to the one or more waveguides, the two or more paths each enabling the propagation of one or more modes;
controlling the propagation characteristic in at least one of the paths;
combining the two or more paths into a receive signal; and
receiving the receive signal at a receiver.
5. The method as recited in claim 1 wherein the propagation characteristic controlled is phase.
6. The method as recited in claim 5 wherein a further propagation characteristic controlled is amplitude.
7. The method as recited in claim 6 wherein a yet further propagation characteristic controlled is polarization.
8. The method as recited in claim 1 wherein the propagation characteristic controlled is amplitude.
9. The method as recited in claim 1 wherein the propagation characteristic controlled is polarization.
10. The method as recited in claim 1 wherein the propagation characteristic controlled is frequency.
11. The method as recited in claim 1 wherein the propagation characteristic controlled is physical orientation.
12. The method as recited in claim 1 wherein the one or more waveguides is comprised of a circular waveguide.
13. The method as recited in claim 12 wherein the one or more waveguides are further comprised of a circular corrugated waveguide.
14. The method as recited in claim 13 wherein a first mode is transverse electric 01 (TE01) mode, and a second mode is hybrid electric 11 (HE11) mode.
15. The method as recited in claim 1 wherein the one or more waveguides is a rectangular waveguide.
16. A method of steering an electromagnetic beam comprising:
propagating a first radio frequency (RF) signal in a first waveguide having a first mode;
propagating a second RF signal in a second waveguide having a second mode; and
controlling a propagation parameter of at least one of the signals to steer the electromagnetic beam.
17. The method as recited in claim 16 further comprising propagating the first and second RF signals together in a common waveguide.
18. The method as recited in claim 16 further comprising:
generating a transmit signal at a transmitter;
splitting the transmit signal into the first and second RF signals;
propagating the first and second RF signals along respective first and second paths and controlling the propagation parameters of at least one of the paths; and
coupling the respective first and second paths to the first and second waveguides.
19. The method as recited in claim 16 further comprising:
coupling the first and second waveguides to respective first and second paths and controlling the propagation parameters of at least one of the paths;
combining the first and second paths into a receive signal; and
receiving the receive signal at a receiver.
20. The method as recited in claim 16 wherein the propagation parameter controlled is phase.
21. The method as recited in claim 20 wherein a further propagation parameter controlled is amplitude.
22. The method as recited in claim 21 wherein a yet further propagation parameter controlled is polarization.
23. The method as recited in claim 16 wherein the propagation parameter controlled is amplitude.
24. The method as recited in claim 16 wherein the propagation parameter controlled is polarization.
25. The method as recited in claim 16 wherein the propagation parameter controlled is frequency.
26. The method as recited in claim 16 wherein the propagation parameter controlled is physical orientation.
27. The method as recited in claim 17 wherein the common waveguide is circular waveguide.
28. The method as recited in claim 16 wherein the first waveguide is circular waveguide and the second waveguide is circular corrugated waveguide.
29. The method as recited in claim 28 wherein the first mode is transverse electric 01 (TE01) mode, and the second mode is hybrid electric 11 (HE11) mode.
30. The method as recited in claim 16 wherein the first and second waveguides are rectangular waveguides.
31. An antenna feed comprising:
one or more waveguides, for propagating a signal in multiple modes, coupled to an antenna; and
a controller, for controlling a propagation characteristic of the respective modes, relative to each other, to steer an electromagnetic beam of the antenna.
32. The antenna feed as recited in claim 31 wherein a common waveguide propagates the signal in multiple modes.
33. The antenna feed as recited in claim 31 further comprising:
a transmitter for generating a transmit signal;
a splittercombiner for splitting the transmit signal along a first and second path, the first and second paths respectively coupled to the one or more waveguides, and the controller controlling the propagation characteristic in at least one of the paths.
34. The antenna feed as recited in claim 31 further comprising:
a first and second path, respectively coupled to the one or more waveguides, and the controller controlling the propagation characteristic in at least one of the paths;
a splittercombiner for combining the first and second paths into a receive signal; and
a receiver for receiving the receive signal.
35. The antenna feed as recited in claim 31 wherein the propagation characteristic controlled is phase.
36. The antenna feed as recited in claim 35 wherein a further propagation characteristic controlled is amplitude.
37. The antenna feed as recited in claim 36 wherein a yet further propagation characteristic controlled is polarization.
38. The antenna feed as recited in claim 31 wherein the propagation characteristic controlled is amplitude.
39. The antenna feed as recited in claim 31 wherein the propagation characteristic controlled is polarization.
40. The antenna feed as recited in claim 31 wherein the propagation characteristic controlled is frequency.
41. The antenna feed as recited in claim 31 wherein the propagation characteristic controlled is physical orientation.
42. The antenna feed as recited in claim 31 wherein the one or more waveguides is a circular waveguide.
43. The antenna feed as recited in claim 42 wherein the one or more waveguides are further comprised of a circular corrugated waveguide.
44. The antenna feed as recited in claim 43 wherein the first mode is transverse electric 01 (TE01) mode, and the second mode is hybrid electric 11 (HE11) mode.
45. The antenna feed as recited in claim 31 wherein the one or more waveguides is a rectangular waveguide.
46. An apparatus for steering an electromagnetic beam comprising:
a first waveguide for propagating a first radio frequency (RF) signal having a first mode;
a second waveguide for propagating a second RF signal having a second mode; and
a controller for controlling a propagation parameter of at least one of the signals to steer the electromagnetic beam.
47. The apparatus as recited in claim 46 further comprising a common waveguide for propagating the first and second RF signals together.
48. The apparatus as recited in claim 46 further comprising:
a transmitter for generating a transmit signal;
a splittercombiner for splitting the transmit signal into the first and second RF signals; and
a first and second path, respectively coupled to the first and second waveguides, the controller controlling the propagation parameter of at least one of the paths.
49. The apparatus as recited in claim 46 further comprising:
a first and second path, respectively coupled to the first and second waveguides, the controller controlling the propagation parameter of at least one of the paths;
a splittercombiner for combining the first and second signals into a receive signal; and
a receiver to receive the receive signal.
50. The apparatus as recited in claim 46 wherein the propagation parameter controlled is phase.
51. The apparatus as recited in claim 50 wherein the propagation parameter controlled is amplitude.
52. The apparatus as recited in claim 51 wherein the propagation parameter controlled is polarization.
53. The apparatus as recited in claim 46 wherein the propagation parameter controlled is amplitude.
54. The apparatus as recited in claim 46 wherein the propagation parameter controlled is polarization.
55. The apparatus as recited in claim 46 wherein the propagation parameter controlled is frequency.
56. The apparatus as recited in claim 46 wherein the propagation parameter controlled is physical orientation.
57. The apparatus as recited in claim 47 wherein the common waveguide is a circular waveguide.
58. The apparatus as recited in claim 46 wherein the first waveguide is a circular waveguide and the second waveguide is a circular corrugated waveguide.
59. The apparatus as recited in claim 58 wherein the first mode is transverse electric 01 (TE01) mode, and the second mode is hybrid electric (HE11) mode.
60. The apparatus as recited in claim 45 wherein the first and second waveguides are rectangular waveguides.

The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.

What is claimed is:

1. A method of removing growth from an electrode during an electrowinning process, comprising the steps of:
placing a scraper between a first electrode and a second electrode of opposing polarity; and
moving the scraper a minimal distance relative to the electrodes.
2. The method of claim 1, wherein the scraper has a surface area larger than a surface area of the electrode.
3. The method of claim 1, wherein the step of moving the scraper a minimal distance relative to the electrodes comprises moving the scraper less than one inch relative to the electrode.
4. The method of claim 1, wherein the step of moving the scraper comprises the step of moving the scraper by vibration.
5. The method of claim 1, wherein the step of moving the scraper comprises the step of oscillating the scraper relative to the electrode.
6. The method of claim 1, wherein the step of moving the scraper comprises the step of moving the scraper to remove dendrite growth from the first electrode acting as a cathode.
7. An electrolytic cell, comprising:
a plurality of electrodes of opposing polarity; and
a scraper placed between each of the plurality of electrodes of opposing polarity, wherein the scraper moves a minimal distance relative to the plurality of electrodes.
8. The electrolytic cell of claim 7, wherein the electrolytic cell further comprises a motor for periodically moving the scraper.
9. The electrolytic cell of claim 7, wherein the scraper has a larger surface area than the surface area of one of the plurality of electrodes.
10. The electrolytic cell of claim 7, wherein the scraper has a plurality of holes to allow for flow of electrolyte within the electrolytic cell.
11. The electrolytic cell of claim 7, wherein the scraper is made from a non-conductive material.
12. An electrolytic cell, comprising
a plurality of cathodes interspersed among a plurality of anodes, wherein the plurality of cathodes and plurality of anodes form a plurality of electrodes spaced and suspended in parallel fashion in an electrolyte solution;
a plurality of scrapers, wherein each scraper of the plurality of scrapers is placed between each of the plurality of electrodes in parallel fashion and wherein the scraper moves a minimal distance relative to the plurality of electrodes.
13. The electrolytic cell of claim 12, wherein the plurality of scrapers is coupled together to move in parallel as a group.
14. The electrolytic cell of claim 12, wherein the electrolytic cell further comprises a motor for periodically moving the scraper.
15. The electrolytic cell of claim 12, wherein each scraper has a larger surface area than the surface area of one of the plurality of electrodes so that the scraper extends beyond the edges of one of the plurality of electrodes.
16. The electrolytic cell of claim 12, wherein each scraper has a plurality of holes to allow for flow of electrolyte within the electrolytic cell.
17. The electrolytic cell of claim 12, wherein the scraper is made from perforated polypropylene.
18. The electrolytic cell of claim 12, wherein the scraper rubs directly against dendrite growth to remove the dendrite growth from the plurality of cathodes.

What is claimed is:

1. A spacecraft embedded in a reference frame rotating relative to inertial space comprising:
actuators for maneuvering the spacecraft with respect to the reference frame;
an attitude measurement device that measures the pitch and roll attitude of the spacecraft with respect to the reference frame;
a control device adapted to keep the roll and pitch angles of the spacecraft close to the commanded roll and pitch angles; and
a harmonic torque estimator adapted to read the commanded angular velocity of the spacecraft relative to an inertial frame, read momentum wheel speeds, read known predicted external torques and combines angular velocity, measured wheel speed and known external torque to produce an estimated observable periodic torque.
2. The spacecraft of claim 1 including a rate measurement device wherein the control device estimates both observable and unobservable periodic torque while the onboard rate measurement device is ON.
3. The spacecraft of claim 1 including a momentum storage device providing a non-zero average momentum perpendicular to the orbital plane.
4. The spacecraft of claim 3 including a rate measurement device wherein the control device estimates both observable and unobservable periodic torque while the onboard rate measurement device is ON.
5. The spacecraft of claim 1 wherein momentum stored in momentum wheels is kept close to ideal periodic momentum trajectory.
6. An attitude control system for a spacecraft comprising:
a harmonic torque estimator adapted to estimate a periodic disturbance torque signal and a periodic momentum profile signal based on disturbances observable from the available spacecraft sensors;
an attitude profile generator adapted to provide reference attitude command and a rate command for the spacecraft to follow;
a feedback control device adapted to measure roll and pitch angles to the commanded roll and pitch angles issued by the attitude profile generator and output a torque that is combined with the periodic disturbance torque estimate to form an actuator torque command; and
a momentum management device adapted to use the estimated periodic momentum profile to improve momentum management of the spacecraft.
7. The attitude control system of claim 6 wherein in the step of combining the periodic disturbance torque signal estimate is a feed forward signal issued by the harmonic torque estimator.
8. The attitude control system of claim 6 wherein the periodic disturbance torque signal estimate is fed forward to actuators in the spacecraft dynamic system to improve yaw pointing.
9. The attitude control system of claim 6 wherein the harmonic torque estimator is adapted to measure harmonic torque from body-fixed angular momentum dynamics, wherein the angular momentum is a combination of wheel momentum and spacecraft angular rate.
10. The attitude control system of claim 6 wherein the harmonic torque estimator is adapted to measure observable harmonic torque from body-fixed angular momentum dynamics, wherein the angular momentum is estimated without rate sensor measurements.
11. The attitude control system of claim 6 wherein spacecraft roll and pitch angles are measured from an earth sensor.
12. The attitude control system of claim 6 wherein the momentum management device is further adapted to issue a thruster torque command when a difference between wheel momentum and a predetermined nominal wheel momentum value exceeds a threshold level, the predetermined nominal value being based on the periodic momentum profile provided by the harmonic torque estimator.
13. The attitude control system of claim 6 wherein the harmonic torque estimator further comprises:
a momentum estimator adapted to estimate a body-fixed angular momentum stored in the satellite and generate a momentum error signal;
a harmonic torque Fourier coefficient estimator adapted to output a set of estimated disturbance torque Fourier coefficients for each of the roll and yaw axes developed from the momentum error signal to the momentum profile generator and harmonic torque generator; and
a harmonic torque generator adapted to translate the estimated disturbance torque Fourier coefficients delivered from the harmonic torque Fourier coefficient estimator into the estimated periodic torque.
14. The attitude control system of claim 13 wherein the harmonic torque estimator further comprises a ground prediction module adapted to output a set of predicted Fourier coefficients based on ground models of solar torques to be combined with the set of Fourier coefficients fed to a momentum profile generator and harmonic torque generator.
15. The attitude control system of claim 13 wherein the harmonic torque estimator further comprises a momentum profile generator adapted to integrate the periodic torques to yield a periodic roll and yaw momentum profile.
16. A method of controlling a spacecraft comprising the steps of:
measuring a pitch and roll attitude of the spacecraft;
generating a control torque command designed to keep the roll and pitch angles close to desired roll and pitch angles; and
estimating a periodic disturbance torque
combining the generated control torque command and the estimated periodic torque to produce an actuator torque command.
17. The method of claim 16 wherein inclusion of the periodic torque in the actuator torque improves yaw pointing.
18. The method of claim 16 further comprising the step of using a harmonic torque estimator to produce the estimated periodic torque.
19. The method of claim 16 wherein the step of estimating a periodic torque further comprises the steps of:
reading a commanded angular velocity of the spacecraft relative to an inertial frame;
reading momentum wheel speeds;
reading known predicted external torques; and
combining the angular velocity, wheel momentum and know external torques to produce the estimated periodic observable torque.
20. The method of claim 16 wherein the step of estimating a periodic torque further comprises the steps of:
reading an angular velocity measurement device
reading momentum wheel speeds;
reading known predicted external torques; and
combining the angular velocity, wheel momentum and known external torques to produce the estimated periodic observable and unobservable torques.

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 free-flowing non-deliquescent benzalkonium salt having at least one C8-25 alkyl group and obtained by benzylating a tertiary amine consisting of at least 90% by weight of a single homologue, said salt containing from 3 to 10% by weight of water based on the total weight of said salt.
2. A salt according to claim 1, having an equilibrium water content below 10% based on the total weight of said salt at 40 C. in an atmosphere having 65% humidity.
3. A salt according claim 1 having an inorganic salt content of less than 12% by weight based on the total weight of said salt.
4. salt according claim 1 having an inorganic salt content of less than 9% by weight based on the total weight of said salt.
5. A salt according to claim 1 having an inorganic salt content of less than 0.5% by weight based on the total weight of said salt.
6. A salt according to claim 1 wherein said tertiary amine consists of more than 95%, by weight of said amine, of a single homologue.
7. A salt according to claim 6 wherein the purity of the tertiary amine is 96 to 98%.
8. A salt according to claim 6 wherein the amine feedstock is lauryl dimethylamine.
9. A salt according to claim 1 wherein the water content is reduced to a value of from 3.5 to 9% by weight based on the total weight of said salt.
10. A salt according to claim 8 wherein the water content is reduced to a value of from 3.5 to 9% by weight based on the total weight of said salt.
11. A salt according to claim 2 having an inorganic salt content of less than 12% by weight based on the total weight of said salt.
12. A salt according to claim 2 having an inorganic salt content of less than 9% by weight based on the total weight of said salt.
13. A salt according to claim 2 having an inorganic salt content of less than 0.5% by weight based on the total weight of said salt.
14. A salt according to claim 7 wherein the amine feedstock is lauryl dimethylamine.