Abstract: Methods and related apparatus for improving synchronization of two or more engines on an aircraft are disclosed. Such method may be used where each engine comprises a first spool and a second spool, and, where a rotational speed of a first spool of a first engine has been substantially synchronized with a rotational speed of a first spool of a second engine. An exemplary method comprises receiving a value of a sensed parameter useful in controlling the first engine; adding a bias to the value; and using the biased value for controlling the first engine to cause a change in rotational speed of the second spool of the first engine in relation to the rotational speed of the first spool of the first engine.

Abstract: A cushioning element for use in a vehicle, for example in an aircraft, includes at least one tuned absorber embedded within the cushioning element. The tuned absorber is tuned to absorb noise at a predetermined frequency of at least 20 Hz. A method of providing noise absorption within a cabin of a vehicle includes determining a predetermined frequency of at least 20 Hz of an undesirable noise within the cabin, and configuring an internal structure of a cushioning element to define a tuned absorber tuned to absorb noise at the predetermined frequency, the cushioning element in use being located in the cabin.

Abstract: An air duct includes a first chamber and a second chamber, the first chamber being defined between an air handling device and the second chamber, and the second chamber being defined between the first chamber and an environment exterior to the air duct, a plurality of first openings between the first chamber and the second chamber, a plurality of second openings between the second chamber and the environment exterior to the air duct, and a sound absorbing material defining at least a portion of an interior surface of at least one of the first chamber and the second chamber.

Abstract: A duct coupling system includes a first and second duct, a vibration attenuation system, a rigid ring, and a fastening system. The first duct has a first flange aligned with a second flange of the second duct. The vibration attenuating system abuts a first side and a second side of the first flange and abuts a first side of the second flange. A portion of the vibration attenuating system encircles the first duct. The vibration attenuating system is configured to attenuate vibrations passing between the first and second ducts. The rigid ring encircles the first duct and abuts the vibration attenuation system. The fastening system couples the first duct to the second duct and compresses the vibration attenuating system. The rigid ring does not contact the first duct and the first duct does not contact the second duct.

Abstract: Methods and related apparatus for improving synchronization of two or more engines on an aircraft are disclosed. Such method may be used where each engine comprises a first spool and a second spool, and, where a rotational speed of a first spool of a first engine has been substantially synchronized with a rotational speed of a first spool of a second engine. An exemplary method comprises receiving a value of a sensed parameter useful in controlling the first engine; adding a bias to the value; and using the biased value for controlling the first engine to cause a change in rotational speed of the second spool of the first engine in relation to the rotational speed of the first spool of the first engine.

Abstract: Methods and related apparatus for improving synchronization of two or more engines on an aircraft are disclosed. Such method may be used where each engine comprises a first spool and a second spool, and, where a rotational speed of a first spool of a first engine has been substantially synchronized with a rotational speed of a first spool of a second engine. An exemplary method comprises receiving a value of a sensed parameter useful in controlling the first engine; adding a bias to the value; and using the biased value for controlling the first engine to cause a change in rotational speed of the second spool of the first engine in relation to the rotational speed of the first spool of the first engine.

Abstract: An isolation mount connecting a panel to a structure includes a housing disposable on the structure, a fastener receiver with a panel-facing surface, and a damper connecting the housing to the fastener receiver. The panel-facing surface of the fastener receiver defines a static coefficient of friction between the panel-facing surface and the panel discouraging rotation of panel-facing surface around a longitudinal axis.

Abstract: A duct coupling system includes a first and second duct, a vibration attenuation system, a rigid ring, and a fastening system. The first duct has a first flange aligned with a second flange of the second duct. The vibration attenuating system abuts a first side and a second side of the first flange and abuts a first side of the second flange. A portion of the vibration attenuating system encircles the first duct. The vibration attenuating system is configured to attenuate vibrations passing between the first and second ducts. The rigid ring encircles the first duct and abuts the vibration attenuation system. The fastening system couples the first duct to the second duct and compresses the vibration attenuating system. The rigid ring does not contact the first duct and the first duct does not contact the second duct.

Abstract: A cushioning element for use in a vehicle, for example in an aircraft, includes at least one tuned absorber embedded within the cushioning element. The tuned absorber is tuned to absorb noise at a predetermined frequency of at least 20 Hz. A method of providing noise absorption within a cabin of a vehicle includes determining a predetermined frequency of at least 20 Hz of an undesirable noise within the cabin, and configuring an internal structure of a cushioning element to define a tuned absorber tuned to absorb noise at the predetermined frequency, the cushioning element in use being located in the cabin.

Abstract: An air duct includes a first chamber and a second chamber, the first chamber being defined between an air handling device and the second chamber, and the second chamber being defined between the first chamber and an environment exterior to the air duct, a plurality of first openings between the first chamber and the second chamber, a plurality of second openings between the second chamber and the environment exterior to the air duct, and a sound absorbing material defining at least a portion of an interior surface of at least one of the first chamber and the second chamber.

Abstract: Methods and related apparatus for improving synchronization of two or more engines on an aircraft are disclosed. Such method may be used where each engine comprises a first spool and a second spool, and, where a rotational speed of a first spool of a first engine has been substantially synchronized with a rotational speed of a first spool of a second engine. An exemplary method comprises receiving a value of a sensed parameter useful in controlling the first engine; adding a bias to the value; and using the biased value for controlling the first engine to cause a change in rotational speed of the second spool of the first engine in relation to the rotational speed of the first spool of the first engine.

Abstract: Methods and related apparatus for improving synchronization of two or more engines on an aircraft are disclosed. Such method may be used where each engine comprises a first spool and a second spool, and, where a rotational speed of a first spool of a first engine has been substantially synchronized with a rotational speed of a first spool of a second engine. An exemplary method comprises receiving a value of a sensed parameter useful in controlling the first engine; adding a bias to the value; and using the biased value for controlling the first engine to cause a change in rotational speed of the second spool of the first engine in relation to the rotational speed of the first spool of the first engine.

Abstract: An isolation mount connecting a panel to a structure includes a housing disposeable on the structure, a fastener receiver with a panel-facing surface, and a damper connecting the housing to the fastener receiver. The panel-facing surface of the fastener receiver defines a static coefficient of friction between the panel-facing surface and the panel discouraging rotation of panel-facing surface around a longitudinal axis.

Abstract: Methods and related apparatus for improving synchronization of two or more engines on an aircraft are disclosed. Such method may be used where each engine comprises a first spool and a second spool, and, where a rotational speed of a first spool of a first engine has been substantially synchronized with a rotational speed of a first spool of a second engine. An exemplary method comprises receiving a value of a sensed parameter useful in controlling the first engine; adding a bias to the value; and using the biased value for controlling the first engine to cause a change in rotational speed of the second spool of the first engine in relation to the rotational speed of the first spool of the first engine.

Abstract: Thermal 3-D microstructuring of photonic structures is provided by depositing laser energy by non-linear absorption into a focal volume about each point of a substrate to be micromachined at a rate greater than the rate that it diffuses thereout to produce a point source of heat in a region of the bulk larger than the focal volume about each point that structurally alters the region of the bulk larger than the focal volume about each point, and by dragging the point source of heat thereby provided point-to-point along any linear and non-linear path to fabricate photonic structures in the bulk of the substrate. Exemplary optical waveguides and optical beamsplitters are thermally micromachined in 3-D in the bulk of a glass substrate. The total number of pulses incident to each point is controlled, either by varying the rate that the point source of heat is scanned point-to-point and/or by varying the repetition rate of the laser, to select the mode supported by the waveguide or beamsplitter to be micromachined.

Abstract: Thermal 3-D microstructuring of photonic structures is provided by depositing laser energy by non-linear absorption into a focal volume about each point of a substrate to be micromachined at a rate greater than the rate that it diffuses thereout to produce a point source of heat in a region of the bulk larger than the focal volume about each point that structurally alters the region of the bulk larger than the focal volume about each point, and by dragging the point source of heat thereby provided point-to-point along any linear and non-linear path to fabricate photonic structures in the bulk of the substrate. Exemplary optical waveguides and optical beamsplitters are thermally micromachined in 3-D in the bulk of a glass substrate. The total number of pulses incident to each point is controlled, either by varying the rate that the point source of heat is scanned point-to-point and/or by varying the repetition rate of the laser, to select the mode supported by the waveguide or beamsplitter to be micromachined.

Abstract: Thermal 3-D microstructuring of photonic structures is provided by depositing laser energy by non-linear absorption into a focal volume about each point of a substrate to be micromachined at a rate greater than the rate that it diffuses thereout to produce a point source of heat in a region of the bulk larger than the focal volume about each point that structurally alters the region of the bulk larger than the focal volume about each point, and by dragging the point source of heat thereby provided point-to-point along any linear and non-linear path to fabricate photonic structures in the bulk of the substrate. Exemplary optical waveguides and optical beamsplitters are thermally micromachined in 3-D in the bulk of a glass substrate. The total number of pulses incident to each point is controlled, either by varying the rate that the point source of heat is scanned point-to-point and/or by varying the repetition rate of the laser, to select the mode supported by the waveguide or beamsplitter to be micromachined.