Abstract: Disclosed herein is a wearable article, comprising a fabric. In some embodiments, the fabric comprises an inner material layer which forms an inner surface of the wearable article, an outer material layer which forms an outer surface of the wearable article; and one or more intermediate material layers disposed between the inner and outer material layers. In some embodiments, the inner, outer, and one or more intermediate material layers are knitted together to provide a combination of two or more of: two or more compression zones; two or more mobility zones; two or more materials; or one or more electronic components.

Abstract: A continuous wave (CW) heterodyne light detection and ranging (LIDAR) air velocity sensor system that comprises a first light emitting structure arranged to send a signal light in a first direction in space; a second light emitting structure arranged to produce a local oscillator light having a wavelength different from the wavelength of the signal light by a predetermined wavelength; a receiver arranged to receive light from said first direction in space; and a first optical mixer for mixing the received light with said local oscillator light.

Abstract: A method of testing a SMA element includes connecting the SMA element to a validation tool, and applying an electrical current to the SMA element over a test cycle. A resistance of the SMA element during the test cycle is measured, while the electrical current is being applied. The measured resistance of the SMA element during the test cycle is correlated to an estimated strain value of the SMA element during the test cycle. A temperature of the SMA element during the test cycle is estimated. A stress in the SMA element during the test cycle is estimated from a stress predicting grid, using the estimated strain value and the estimated temperature of the SMA element during the test cycle. The proper functionality of the SMA element may be determined based on the estimated stress in the SMA element.

Abstract: A negative stiffness structure for vibration isolation, shock mitigation, and/or signal processing includes a flexible tensile member and a curved compressive member. A first end of the tensile member is attached to a first structure. A first end of the curved compressive member is coupled to a first structure and a second end of the curved compressive member is coupled to a second end of the flexible tensile member. A length of the tensile member is greater than a length of the compressive member. A tip of the negative stiffness structure is configured to exhibit a negative stiffness mechanical response to a load applied to the tip. The negative stiffness mechanical response acts in a direction orthogonal to the length of the tensile member.

Abstract: Techniques for fabricating a semiconductor chip having a curved surface include placing a substantially flat photonic sensor chip on a recessed surface of a mold such that an active region of the photonic sensor chip at least partially covers a concave central region of the mold and an inactive region of the photonic sensor chip at least partially covers a convex peripheral region of the mold. The mold has a radially varying curvature and the recessed surface includes the concave central region and the convex peripheral region concentrically surrounding the concave central region. Pressure may be applied on the photonic sensor chip to press and bend the photonic sensor chip into the mold.

Abstract: A continuous wave (CW) heterodyne light detection and ranging (LIDAR) air velocity sensor system that comprises a first light emitting structure arranged to send a signal light in a first direction in space; a second light emitting structure arranged to produce a local oscillator light having a wavelength different from the wavelength of the signal light by a predetermined wavelength; a receiver arranged to receive light from said first direction in space; and a first optical mixer for mixing the received light with said local oscillator light.

Abstract: Techniques for fabricating a semiconductor chip having a curved surface include placing a substantially flat photonic sensor chip on a recessed surface of a mold such that an active region of the photonic sensor chip at least partially covers a concave central region of the mold and an inactive region of the photonic sensor chip at least partially covers a convex peripheral region of the mold. The mold has a radially varying curvature and the recessed surface includes the concave central region and the convex peripheral region concentrically surrounding the concave central region. Pressure may be applied on the photonic sensor chip to press and bend the photonic sensor chip into the mold.

Abstract: A method of testing a SMA element includes connecting the SMA element to a validation tool, and applying an electrical current to the SMA element over a test cycle. A resistance of the SMA element during the test cycle is measured, while the electrical current is being applied. The measured resistance of the SMA element during the test cycle is correlated to an estimated strain value of the SMA element during the test cycle. A temperature of the SMA element during the test cycle is estimated. A stress in the SMA element during the test cycle is estimated from a stress predicting grid, using the estimated strain value and the estimated temperature of the SMA element during the test cycle. The proper functionality of the SMA element may be determined based on the estimated stress in the SMA element.

Abstract: A negative stiffness structure for vibration isolation, shock mitigation, and/or signal processing includes a flexible tensile member and a curved compressive member. A first end of the tensile member is attached to a first structure. A first end of the curved compressive member is coupled to a first structure and a second end of the curved compressive member is coupled to a second end of the flexible tensile member. A length of the tensile member is greater than a length of the compressive member. A tip of the negative stiffness structure is configured to exhibit a negative stiffness mechanical response to a load applied to the tip. The negative stiffness mechanical response acts in a direction orthogonal to the length of the tensile member.

Abstract: A variable stiffness structure configured to support a variable load, the variable stiffness structure including a shaft coupled to the variable load, a negative stiffness element, a clutch coupled to the negative stiffness element and configured to disengage and to engage the shaft, in response to a change in the variable load, while the structure supports the variable load.

Abstract: A negative stiffness structure for vibration isolation, shock mitigation, and/or signal processing includes a flexible tensile member and a curved compressive member. A first end of the tensile member is attached to a first structure. A first end of the curved compressive member is coupled to a first structure and a second end of the curved compressive member is coupled to a second end of the flexible tensile member. A length of the tensile member is greater than a length of the compressive member. A tip of the negative stiffness structure is configured to exhibit a negative stiffness mechanical response to a load applied to the tip. The negative stiffness mechanical response acts in a direction orthogonal to the length of the tensile member.

Abstract: Techniques for fabricating a semiconductor chip having a curved surface may include placing a substantially flat semiconductor chip in a recess surface of a concave mold such that corners or edges of the semiconductor chip are unconstrained or are the only portions of the semiconductor chip in physical contact with the concave mold; and bending the substantially flat semiconductor chip to form a concave shaped semiconductor chip by applying a force on the semiconductor chip toward the bottom of the recessed surface. The corners or edges of the semiconductor chip move or slide relative to the recess surface during the bending.

Abstract: Systems and methods are provided for feeding thread at a knitting machine. One embodiment is a thread feeding device which includes a spool that supplies thread to a knitting device through a thread path and a motor that drives the spool. The device and further includes a mobile guide in the thread path that changes position due to changes in thread tension as the knitting device draws thread through the mobile guide. The thread feeding device also includes a sensor that measures a change in position of the mobile guide, and a controller that determines an amount of tension applied to the thread by the knitting device based on the change in position, and adjusts a speed of a motor that drives the spool based on the amount of tension.

Abstract: A slack compensator includes a stator fixedly attachable to a base and a shuttle. The shuttle is selectably movable from a first position on the stator to a second position on the stator. The shuttle is selectably releasably attached to the stator in the first position. The shuttle is to be permanently captured upon reaching the second position. The slack compensator is attachable to an SMA wire for removing slack that develops in the SMA wire during a plurality of break-in cycles.

Abstract: Systems and methods are provided for feeding thread at a knitting machine. One embodiment is a thread feeding device which includes a spool that supplies thread to a knitting device through a thread path and a motor that drives the spool. The device and further includes a mobile guide in the thread path that changes position due to changes in thread tension as the knitting device draws thread through the mobile guide. The thread feeding device also includes a sensor that measures a change in position of the mobile guide, and a controller that determines an amount of tension applied to the thread by the knitting device based on the change in position, and adjusts a speed of a motor that drives the spool based on the amount of tension.

Abstract: In an embodiment, a tunable stiffness mechanical filter is provided including an input coupler to a negative stiffness structure with a negative stiffness characteristic, and further including a tuner for tuning the negative stiffness structure. An output sensor is located along the negative stiffness structure. The filter may include an amplifier and/or a driver coupled between the output sensor and the negative stiffness structure.

Abstract: A slack compensator includes a stator fixedly attachable to a base and a shuttle. The shuttle is selectably movable from a first position on the stator to a second position on the stator. The shuttle is selectably releasably attached to the stator in the first position. The shuttle is to be permanently captured upon reaching the second position. The slack compensator is attachable to an SMA wire for removing slack that develops in the SMA wire during a plurality of break-in cycles.

Abstract: A microstructured reconfigurable or morphing composite material with controlled anisotropic deformation properties. The composite material provides highly controlled deformation and stiffness properties. Microscopic three dimensional structures are included in the composite material to control its deformation kinematics and stiffness properties. The composite material has highly segregated in-plane and out-of-plane stiffness properties.

Abstract: A variable stiffness structure configured to support a variable load, the variable stiffness structure including a positive stiffness element coupled to the variable load, a negative stiffness element, a hydraulic system coupled to the positive and negative stiffness elements and configured to adjust a relative position of the positive and negative stiffness elements in response to a change in the variable load, while the variable stiffness structure supports the variable load.

Abstract: A method of testing a shape memory alloy (SMA) actuated device includes cyclically operating the device. The method further includes determining a number of cycles in a functional life of the device based on observations of the device during the cyclical operation. The functional life is a range of consecutive cycles of operation of the device beginning with a first cycle during which the device performs within a specified limit. The functional life is immediately followed by a cycle during which the device performs outside of the specified limit. The method still further includes applying a progressive substitution sub-process to identify an opportunity to increase the number of cycles in the functional life of the device.