Abstract: The ultra-low frequency acoustic absorber (10) includes a hollow housing (12) having opposed first and second open ends (22, 24), and a plurality of metallic mesh layers (16) stacked within the housing (12). In order to secure the plurality of metallic mesh layers (16) within the hollow housing (12), first and second mesh covers (18, 20) may cover the first and second open ends (22, 24) of the hollow housing (12), respectively. At least one spacer (14) may be provided to form a gap between the housing (12) and a support surface, such as a hard wall (W) or the like. The at least one spacer (14) may have a length sufficient to space the ultra-low frequency acoustic absorber (10) at the position of optimal absorption based on an acoustic soft 10 boundary condition (ASBC).

Abstract: Rotational translation of an inertial mass rotor is used for providing damping of low frequency noise and vibration. An axial component is mounted so as to translate axial movement of an inertial linearly-displaceable member to rotational movement of an inertial mass rotor. The translation to rotational movement of the inertial mass rotor provides inertial amplification in the form of translational-rotational coupling. This enables the construction of a compact assembly, which allows light ultra-low frequency resonances to be concentrated, and which absorbs such low frequency noise energy.

Abstract: The ultra-low frequency acoustic absorber (10) includes a hollow housing (12) having opposed first and second open ends (22, 24), and a plurality of metallic mesh layers (16) stacked within the housing (12). In order to secure the plurality of metallic mesh layers (16) within the hollow housing (12), first and second mesh covers (18, 20) may cover the first and second open ends (22, 24) of the hollow housing (12), respectively. At least one spacer (14) may be provided to form a gap between the housing (12) and a support surface, such as a hard wall (W) or the like. The at least one spacer (14) may have a length sufficient to space the ultra-low frequency acoustic absorber (10) at the position of optimal absorption based on an acoustic soft 10 boundary condition (ASBC).

Abstract: The dipole-resonator resistive absorber is a metamaterial absorber operating in the microwave regime. A single unit of the dipole-resonator resistive absorber includes a first rectangular conductive ring having a pair of first resistors mounted thereon and in electrical communication therewith, and a plurality of parallel linear arrays of second rectangular conductive rings, where each of the second rectangular conductive rings has a pair of second resistors mounted thereon and in electrical communication therewith. The first rectangular conductive ring is mounted above the plurality of parallel linear arrays of the second rectangular conductive rings, and this structure is backed by an electrically conductive layer. The single unit dipole-resonator resistive absorber may be expanded into an arrayed structure, forming a polarization-independent dipole-resonator resistive absorber.

Abstract: A soft boundary structure is implemented using a resonator structure capable of receiving sound or vibration, establishing resonance coupled with received sound or vibration, and creating a reflection with a pi phase factor. A soft boundary is located on or closely adjacent the resonator structure. The soft boundary cooperates with the resonator structure to attenuate the sound or vibration.

Abstract: An ultra high molecular weight polyethylene (UHMWPE) membrane has at least one nanoporous UHMWPE film, where each of the nanoporous UHMWPE film is biaxial oriented with a thickness of 0.1 to 12 ?m and pores that exclude particles in excess of 10 nm with a total porosity of 65 to 75 percent. The nanoporous UHMWPE film can be coated or laminated by a hydrophilic polymer to form a Janus membrane and can be made with a multilayer composite structure. The UHMWPE membrane can be used in a device for molecular distillation (MD), reverse osmosis (RO), or forward osmosis (FO).

Abstract: The dipole-resonator resistive absorber is a metamaterial absorber operating in the microwave regime. A single unit of the dipole-resonator resistive absorber includes a first rectangular conductive ring having a pair of first resistors mounted thereon and in electrical communication therewith, and a plurality of parallel linear arrays of second rectangular conductive rings, where each of the second rectangular conductive rings has a pair of second resistors mounted thereon and in electrical communication therewith. The first rectangular conductive ring is mounted above the plurality of parallel linear arrays of the second rectangular conductive rings, and this structure is backed by an electrically conductive layer. The single unit dipole-resonator resistive absorber may be expanded into an arrayed structure, forming a polarization-independent dipole-resonator resistive absorber.

Abstract: A soft boundary structure is implemented using a resonator structure capable of receiving sound or vibration, establishing resonance coupled with received sound or vibration, and creating a reflection with a pi phase factor. A soft boundary is located on or closely adjacent the resonator structure. The soft boundary cooperates with the resonator structure to attenuate the sound or vibration.

Abstract: A composite material of Angstrom-scale nanowire arrays in zeolite and its fabrication methods are provided. The zeolite can be prepared by a hydrothermal method and the Angstrom-scale nanowire arrays can be prepared by using zeolite as a template. The zeolite can have porous structures with an average pore size of 0.74 nm and the plurality of nanowires can have an average diameter smaller than 1 nm and can be dispersed on internal or external surfaces of the porous structures. The Angstrom-scale nanowire arrays can be made of aluminum (Al), gallium (Ga), zinc (Zn), or carbon (C). A composite material of the Angstrom-scale aluminum (Al), gallium (Ga), or zinc (Zn) nanowire arrays in zeolite can exhibit characteristics of one-dimensional (1D) superconductor.

Abstract: Rotational translation of an inertial mass rotor is used for providing damping of low frequency noise and vibration. An axial component is mounted so as to translate axial movement of an inertial linearly-displaceable member to rotational movement of an inertial mass rotor. The translation to rotational movement of the inertial mass rotor provides inertial amplification in the form of translational-rotational coupling. This enables the construction of a compact assembly, which allows light ultra-low frequency resonances to be concentrated, and which absorbs such low frequency noise energy.

Abstract: An active sound barrier has at least one passive sound absorber at or near a boundary location. A microphone provides an output to a frequency division module, in which a plural of frequencies are filtered to provide outputs corresponding to frequency segments of the receiving transducer output at respective ones of the frequencies. An active driving circuit drives plural speakers or output transducers at respective ones of the frequencies, with at least a subset of the speakers or output transducers at or close to the barrier. The speakers or output transducers cooperate with the passive sound absorber to reduce noise across a wide frequency band as well as to effect an electrically switchable soft boundary.

Abstract: An active sound barrier has at least one passive sound absorber at or near a boundary location. A microphone provides an output to a frequency division module, in which a plural of frequencies are filtered to provide outputs corresponding to frequency segments of the receiving transducer output at respective ones of the frequencies. An active driving circuit drives plural speakers or output transducers at respective ones of the frequencies, with at least a subset of the speakers or output transducers at or close to the barrier. The speakers or output transducers cooperate with the passive sound absorber to reduce noise across a wide frequency band as well as to effect an electrically switchable soft boundary.

Abstract: An ultra high molecular weight polyethylene (UHMWPE) membrane has at least one nanoporous UHMWPE film, where each of the nanoporous UHMWPE film is biaxial oriented with a thickness of 0.1 to 12 ?m and pores that exclude particles in excess of 10 nm with a total porosity of 65 to 75 percent. The nanoporous UHMWPE film can be coated or laminated by a hydrophilic polymer to form a Janus membrane and can be made with a multilayer composite structure. The UHMWPE membrane can be used in a device for molecular distillation (MD), reverse osmosis (RO), or forward osmosis (FO).

Abstract: A sound absorption panel (201) is constructed on an acoustically thin sheet (203) to provide an acoustic/vibrational energy absorption metamaterial structure. A plurality of dampers (101) are fixed to the acoustically thin sheet (203), and at least a subset of said dampers (101) comprise a support (103) and a flexible membrane (105) supported by the support. The flexible membrane (105) has one or more masses or platelets (107) attached. The dampers (101) in combination with the sheet (203) result in absorption of energy of movement of the sheet (203) resulting from sound transmission or vibrations across the sheet.

Abstract: The present subject matter relates generally to the use of thermally induced self-assembly of surfactants, such as poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) or 4-octylphenol polyethoxylate, to vary the transparency or opacity of a composition containing the same. The compositions of the present subject matter can be used in smart window technologies.

Abstract: A composite material of Angstrom-scale nanowire arrays in zeolite and its fabrication methods are provided. The zeolite can be prepared by a hydrothermal method and the Angstrom-scale nanowire arrays can be prepared by using zeolite as a template. The zeolite can have porous structures with an average pore size of 0.74 nm and the plurality of nanowires can have an average diameter smaller than 1 nm and can be dispersed on internal or external surfaces of the porous structures. The Angstrom-scale nanowire arrays can be made of aluminum (Al), gallium (Ga), zinc (Zn), or carbon (C). A composite material of the Angstrom-scale aluminum (Al), gallium (Ga), or zinc (Zn) nanowire arrays in zeolite can exhibit characteristics of one-dimensional (1D) superconductor.

Abstract: A sound suppression structure is made up of plural planar vibrational units, which establish plural resonant frequencies. A dissipative layer is positioned on a front side of the vibrational units with a separation between the dissipative layer and the planar vibrational units sufficient to permit substantially free movement of the planar vibrational units. A shallow sealed gas cell array is positioned behind vibrational units, with one or more of the planar vibration units forming one side of each sealed gas cell in the array. The sealed gas cell array interacts with the planar vibrational units to absorb energy at the resonant frequencies. The dissipative layer enhances absorption efficiency, resulting in absorption of energy at frequencies other than the resonant frequencies, and the combination of the planar vibrational unit, the shallow sealed gas cells and the dissipative layer providing a plurality of resonant modes for broadband sound absorption.

Abstract: GER fluids are improved by the addition of a polar molecule additive. By addition of a polar molecule additive, yield stresses under electric field are improved by over 50% while the current density is reduced to less than a quarter of the original GER. The reversible response time still remains the same, and the sedimentation stability is greatly enhanced. The zero field viscosity of the modified GER fluid remains the same as that of the original GER fluid without the additive. The improved GER characteristics improve general functionality as an electrical-mechanical interface, attendant with applications to car clutches, fluid brakes, and vehicle shock absorbers.

Abstract: A sound absorbing metamaterial comprises an acoustic impedance-matched surface configured to minimize reflection from an incident acoustic wave. The surface is comprised of an elastic or flexible membrane and a substantially rigid mass mounted on the membrane. A relatively solid surface is provided as a reflective surface and is positioned behind the membrane. The reflective surface is separated by a predetermined distance from the elastic or flexible membrane and forms a fluid space between the membrane and the solid surface. The mass mounted on the membrane, in combination with the elastic membrane establish a plurality of eigenfrequencies.

Abstract: Sound attenuation is performed using a sound attenuation panel using an electromagnetic or electrostatic response unit to modify resonance. The sound attenuation panel has an acoustically transparent planar, rigid frame divided into a plurality of individual cells configured for attenuating sound. In one configuration, each cell has a weight fixed to the membrane. The planar geometry of each said individual cell, the flexibility of the membrane, and the weight establish a base resonant frequency for sound attenuation. The electromagnetic or electrostatic response unit is configured to modify the resonant frequency of the cell.