Abstract: An active noise insulation wall includes an active sound reduction apparatus disposed on an upper end surface of a noise insulation wall. The active sound reduction apparatus comprises a combination of an active acoustic control cell and a sound tube. The active acoustic control cell controls a coming noise such that a diffracted sound pressure component of the coming noise at the upper end surface of the noise insulation wall is actively reduced. The sound tube decreases a sound wave of a frequency different from a target frequency of the active acoustic control cell. Thus, the active noise insulation wall can effectively reduce noises including many frequency components.

Abstract: An active noise insulation wall includes an active sound reduction apparatus disposed on an upper end surface of a noise insulation wall. The active sound reduction apparatus comprises a combination of an active acoustic control cell and a sound tube. The active acoustic control cell controls a coming noise such that a diffracted sound pressure component of the coming noise at the upper end surface of the noise insulation wall is actively reduced. The sound tube decreases a sound wave of a frequency different from a target frequency of the active acoustic control cell. Thus, the active noise insulation wall can effectively reduce noises including many frequency components.

Abstract: A combustor structure of a gas turbine, in which a sheet-like vibration damper, which resonates with the air vibration in the intake chamber and absorbs the energy of the air vibration, is attached to the inner wall of the casing by an attaching member via a space. The sheet-like vibration damper is made of a single-layered thin flat plate or multi-layered thin flat plates. In case of the multi-layered thin flat plate, the air vibration energy in the intake chamber is absorbed not only by resonance but also by friction among the multi-layered thin plates. The sheet-like vibration damper may be made of a three-dimensional profile member having an inner space in which the attaching member is housed. If the thin flat plates are used, the surface areas thereof are not identical. If the three-dimensional profile members are used, the volumes of the inner spaces are not identical. Consequently, the sheet-like vibration damper can absorb and attenuate the vibration energy of different frequencies.

Abstract: A gas turbine combustor in which a part or all of the wall of the combustor disposed within an intake chamber is formed as an acoustic energy absorbing member that can absorb the acoustic energy of a combustion variation generated within the combustor. The acoustic energy absorbing member is constructed of a thin corrugated plate in a circumferential direction, a high-temperature-proof perforated material, or a back plate disposed at the outside of a perforated plate in a radial direction with a distance from the perforated plate. It is also possible to provide a covering member at the outside of the acoustic energy absorbing member in a radial direction, for covering the acoustic energy absorbing member with a distance from the acoustic energy absorbing member. It is preferable that the acoustic energy-absorbing member and/or the covering member are reinforced with a frame that extends in a circumferential direction and/or a longitudinal direction.

Abstract: A gas turbine combustion device comprises a plurality of combustion devices. Each combustion device has an inner cylinder and a tail cylinder in a vehicle chamber. An acoustic sleeve is provided between each inner cylinder and a corresponding outer cylinder in the vehicle chamber. An acoustic coupling effect with a vehicle chamber can be reduced.

Abstract: A combustor structure of a gas turbine, in which a sheet-like vibration damper, which resonates with the air vibration in the intake chamber and absorbs the energy of the air vibration, is attached to the inner wall of the casing by an attaching member via a space.

Abstract: A gas turbine combustor in which a part or all of the wall of the combustor disposed within an intake chamber is formed as an acoustic energy absorbing member that can absorb the acoustic energy of a combustion variation generated within the combustor. The acoustic energy absorbing member is constructed of a thin corrugated plate in a circumferential direction, a high-temperature-proof perforated material, or a back plate disposed at the outside of a perforated plate in a radial direction with a distance from the perforated plate. It is also possible to provide a covering member at the outside of the acoustic energy absorbing member in a radial direction, for covering the acoustic energy absorbing member with a distance from the acoustic energy absorbing member. It is preferable that the acoustic energy-absorbing member and/or the covering member are reinforced with a frame that extends in a circumferential direction and/or a longitudinal direction.

Abstract: A gas turbine combustion device comprises a plurality of combustion devices. Each combustion device has an inner cylinder and a tail cylinder in a vehicle chamber. An acoustic sleeve is provided between each inner cylinder and a corresponding outer cylinder in the vehicle chamber. An acoustic coupling effect with a vehicle chamber can be reduced.

Abstract: An active noise insulation wall includes an active sound reduction apparatus disposed on an upper end surface of a noise insulation wall. The active sound reduction apparatus comprises a combination of an active acoustic control cell and a sound tube. The active acoustic control cell controls a coming noise such that a diffracted sound pressure component of the coming noise at the upper end surface of the noise insulation wall is actively reduced. The sound tube decreases a sound wave of a frequency different from a target frequency of the active acoustic control cell. Thus, the active noise insulation wall can effectively reduce noises including many frequency components.

Abstract: In a noise measuring system comprising a microphone array and a directivity forming section for controlling the direction of directivity of the microphone array, the directivity forming section includes delay section and adding section, and the optimal value of a delay time of the delay section is set in such a manner that a noise isolation characteristic for causing any mobile noise generator not targeted for noise measurement to come off a directional plane or a directional line formed in the direction of directivity of the microphone array and a deterioration characteristic of the directivity of the microphone array balance with each other.

Abstract: An active acoustic wall has sound-pressure detectors provided within respective cells so that a detected signal acts to oscillate an oscillation plate in the cell. A porous material on a surface is thereby provided with a high sound absorption coefficient over a wide frequency range. A space between a porous material or a perforated plate 1 on the surface and a back material fixed on a back side is divided into a plurality of sections so as to form cells 10 containing an air layer or a porous sound-absorbing material. Oscillation plates 6 are arranged within respective cells 10 so as to be driven for oscillation by oscillation-plate driving units 5. Sound-pressure detectors 7 are provided close to the porous material 1 in the cell 10 so that a detected signal is inputted to a signal-processing unit 8. The signal processing unit 8 outputs a signal to the driving unit 5 for oscillating the oscillation plate 6 such that an output of the sound-pressure detector is minimized.

Abstract: A calcium-nickel-misch metal-aluminum quaternary alloy for hydrogen storage having an enhanced hydrogen absorbing/releasing capability which allows for the selection of equilibrium pressures for metal hydride formation and dissociation over a broad temperature range. The alloy has the formula:CaNi.sub.a Mm.sub.b Al.sub.c,wherein Mm is a misch metal; a, b and c are, respectively, atomic ratios of Ni, Mm and Al, with Ca taken as unity; and 5-(b+c)<a.ltoreq.8, 0<b.ltoreq.0.4, and 0<c.ltoreq.0.6.

Abstract: The present invention provides low alloy steels having high strength and toughness, excellent high temperature creep rupture strength and ductility and low sensitivity to temper embrittlement. The alloy steel is a low carbon, low silicon-type Cr-Mo-V low alloy steel, to which are added aluminum, titanium, niobium and Zirconium individually or in combination and further, a small amount of boron.

Abstract: A welding method for stainless steel overlays is disclosed wherein a welded stainless steel overlay is prevented from exfoliating out of an inner surface of a high pressure vessel. Hydrogen exists at a partial pressure of less than 150 kg/cm.sup.2 and a temperature less then 450.degree. C. in the pressure vessel. At least one low alloy steel weld-overlay is preliminarily welded over the inner surface of the pressure vessel. The preliminarily low alloy steel weld-overlay is composed of similar composition to the base metal of the vessel, containing niobium and/or nickel. Thereafter, at least one customary ferritic steel or austenitic steel weld-overlay is welded thereon.