Minimal-Sensing, Passive Force Identification Techniques for a Composite Structural Missile Component

Structural health monitoring systems are often limited to the use of one sensor due to cost, complexity, and weight restrictions. Therefore, there is a need to develop load and damage identification techniques that utilize only one sensor. Two passive force estimation techniques are investigated in this work. The techniques focus on either the shape or the amplitude of the magnitude of the applied force in the frequency domain. Both techniques iteratively reduce an underdetermined set of equations of motion into many overdetermined systems of equations to solve for the force estimates. The techniques are shown to locate and quantify impulsive impacts with over 97% accuracy and non-impulsive impacts with at least 87% accuracy. A filament-wound rocket motor casing is used as a test structure. Impacts not acting at a specific input degree of freedom are also accurately located depending on the distance away from the modeled input degrees of freedom, and damaging impact forces are quantified by making assumptions about the impulsive nature of the applied force

The Next Generation Solar Spectral Irradiance Monitor for the JPSS-TSIS Mission: Instrument Overview and Radiometric Performance

In order to advance understanding of how natural and anthropogenic processes affect Earth’s climate it is critically important to maintain accurate, long-term records of climate forcing. These climate-data records are a time series of measurements of sufficient length, consistency, and continuity to determine true climate variability and change. Quantifying the solar irradiance (both total and spectral) provides the necessary constraint on the total energy input. In particular, the long-term, continuous measurements of solar spectral irradiance (SSI) are needed to characterize poorly understood wavelength-dependent climate processes. The strong reliance on radiative transfer modeling for interpretation and quantification of the deposition of solar radiation in the atmosphere makes it imperative that the spectral distribution of radiant energy entering the atmosphere be known to a high degree of absolute accuracy (tied to international standards). Major measurement challenges in quantifying the influence of SSI variability on climate are achieving sufficient radiometric absolute accuracy and then maintaining (on-orbit) the long-term relative accuracy of the data record. The Total and Spectral Solar Irradiance Sensor (TSIS) Spectral Irradiance Monitor (SIM) is the next generation, space-borne SSI monitor that will fly as part of the dual agency (NASA/NOAA) Joint Polar Satellite System (JPSS) program scheduled for launch in late 2016. The instrument has been designed, characterized and calibrated to achieve unprecedented levels of measurement accuracy (\u3c0.25% absolute) and on-orbit stability (0.01-0.05%/yr.) required to meet the needs of establishing the SSI climate data record across a continuous wavelength region spanning 200 – 2400 nm (96% of the total solar irradiance). The full characterization and calibration follows a measurement equation approach at the unit-level for full validation of the end-to-end performance at the instrument-level. Following this approach, we characterize the SIM instrument as an “absolute” sensor tied to a cryogenic radiometer traceable to the NIST Primary Optical Watt Radiometer (POWR), the primary US standard for radiant power measurements

Calibration of the Spectral Irradiance Monitor in the LASP Spectral Radiometry Facility

The Total and Spectral Solar Irradiance Sensor (TSIS) Spectral Irradiance Monitor (SIM) is the next generation, space-borne SSI monitor that will fly as part of the joint agency (NASA/NOAA) Joint Polar Satellite System (JPSS) program scheduled for launch in late 2016. The instrument has been designed and calibrated to achieve unprecedented levels of measurement accuracy (less than 0.25%) and on-orbit stability required to meet the needs of establishing a complete solar spectral irradiance climate data record. The Spectral Radiometry Facility (SRF) at LASP was developed in order to validate the end-to-end performance of the SIM instrument. This facility includes a test chamber with a 5-axis manipulator that houses the SIM instrument. The illumination source is provided by a NIST Spectral Irradiance and Radiance Responsivity Calibrations using Uniform Sources (SIRCUS) laser system. This laser system provides narrow tunable light from 210-2700 nm. The facility also includes a cryogenic radiometer with a precision aperture that is used to measure the absolute irradiance of the illumination light. This facility thus allows us to illuminate the instrument with a known irradiance, wavelength, and polarization. Additionally, the 5-axis manipulator permits us to test the pointing sensitivity and off-axis performance of the instrument. A series of detailed calibrations of the SIM instrument in this facility have allowed us to fully characterize the instrument wavelength scale, spectral response functions, pointing sensitivity, and radiometric accuracy to better than 0.25%

A Nano-modified superhydrophobic membrane

This paper focuses on the synthesis of super-hydrophobic membranes. The polymer used in this research is polystyrene (PS), which has low surface energy but not low enough to be characterized as a superhydrophobic material. As hydrophobicity is based on low energy surface and surface roughness, the electrospinning technique was selected as the manufacturing technique. N, N' dimethylformamide (DMF) was employed as the PS solvent. Two groups of PS/DMF solutions were investigated i.e. 20/80 and 35/65. To increase even more the hydrophobicity, nanoparticles of silica, graphene, cadmium, and zinc were dispersed into the PS/DMF solutions. In contrast to results previous published in literature, the PS/DMF weight ratio of 20/80 led to water contact angles (WCA) of 148º, which is higher than the contact angle for the 35/65 ratio, i.e. 143º. This fact seems to be due to the presence of non-evaporated solvent into the PS surface as the 35/65 solution was more viscous. The WCA for membranes with 0.5 wt. (%) of graphene reached 152º, 149º-153º for membranes with nanosilica addition, 151º with 5.0 wt. (%) CdS, and 153º, 163º and 168º with the addition of 5 wt. (%), 10 wt. (%) and 15 wt. (%) of ZnS, respectively

Reference genome sequence of the model plant Setaria

International audienc

Reference genome sequence of the model plant Setaria

International audienc