Low cost silicon solar array project. Task 1: Establishment of the feasibility of a process capable of low cost, high volume production of silane, SiH4

The kinetics of the redistribution of dichlorosilane and trichlorosilane vapor over a tertiary amine ion exchange resin catalyst were investigated. The hydrogenation of SiCl4 to form HSiCl3 and the direct synthesis of H2SiCl2 from HCl gas and metallurgical silicon metal were also studied. The purification of SiH4 using activated carbon adsorbent was studied along with a process for storing SiH4 absorbed on carbon. The latter makes possible a higher volumetric efficiency than compressed gas storage. A mini-plant designed to produce ten pounds per day of SiH4 is described

Returning to Learning: Adults' Success in College Is Key to America's Future

Provides an overview of research on adult learners' characteristics, risk factors, and needs at four-year institutions and in for-credit and non-credit courses, and what changes institutions and governments can implement to help adult students succeed

Study of EMIC wave excitation using direct ion measurements

With data from Van Allen Probes, we investigate electromagnetic ion cyclotron (EMIC) wave excitation using simultaneously observed ion distributions. Strong He band waves occurred while the spacecraft was moving through an enhanced density region. We extract from helium, oxygen, proton, and electron mass spectrometer measurement the velocity distributions of warm heavy ions as well as anisotropic energetic protons that drive wave growth through the ion cyclotron instability. Fitting the measured ion fluxes to multiple sinm-type distribution functions, we find that the observed ions make up about 15% of the total ions, but about 85% of them are still missing. By making legitimate estimates of the unseen cold (below ∼2 eV) ion composition from cutoff frequencies suggested by the observed wave spectrum, a series of linear instability analyses and hybrid simulations are carried out. The simulated waves generally vary as predicted by linear theory. They are more sensitive to the cold O+ concentration than the cold He+ concentration. Increasing the cold O+ concentration weakens the He band waves but enhances the O band waves. Finally, the exact cold ion composition is suggested to be in a range when the simulated wave spectrum best matches the observed one

Agri-Environmental Policy at the Crossroads: Guideposts on a Changing Landscape

Agri-environmental policy is at a crossroads. Over the past 20 years, a wide range of policies addressing the environmental implications of agricultural production have been implemented at the Federal level. Those policies have played an important role in reducing soil erosion, protecting and restoring wetlands, and creating wildlife habitat. However, emerging agri-environmental issues, evolution of farm income support policies, and limits imposed by trade agreements may point toward a rethinking of agri-environmental policy. This report identifies the types of policy tools available and the design features that have improved the effectiveness of current programs. It provides an indepth analysis of one policy tool that may be an important component of a future policy package-agri-environmental payments. The analysis focuses on issues and tradeoffs that policymakers would face in designing a program of agri-environmental payments.conservation programs, environmental policy, agricultural policy, policy instruments, agricultural program design, soil erosion, nitrogen runoff, Environmental Economics and Policy,

Driving of Outer Belt Electron Loss by Solar Wind Dynamic Pressure Structures : Analysis of Balloon and Satellite Data

We present observations of similar to 10-60 min solar wind dynamic pressure structures that drive large-scale coherent similar to 20-100 keV electron loss from the outer radiation belt. A combination of simultaneous satellite and Balloon Array for Radiation-belt Relativistic Electron Losses (BARREL) observations on 11-12 January 2014 shows a close association between the pressure structures and precipitation as inferred from BARREL X-rays. Specifically, the structures drive radial ExB transport of electrons up to 1 Earth radii, modulating the free electron energy available for low-frequency plasmaspheric hiss growth, and subsequent hiss-induced loss cone scattering. The dynamic pressure structures, originating near the Sun and commonly observed advecting with the solar wind, are thus able to switch on scattering loss of electrons by hiss over a large spatial scale. Our results provide a direct link between solar wind pressure fluctuations and modulation of electron loss from the outer radiation belt and may explain long-period modulations and large-scale coherence of X-rays commonly observed in the BARREL data set. Plain Language Summary The Earth's low-density magnetosphere is a region of enclosed magnetic field lines that contains energetic electrons ranging from eV to MeV energies. These populations can be greatly enhanced in response to solar driving. Following enhancements, energetic electron populations are depleted on timescales of hours to days by various processes. One important depletion process occurs when an electromagnetic plasma wave called plasmaspheric hiss, which exists within a high plasma density region called the plasmasphere and its (occasional) radial extension called the plume, scatters energetic electrons into the atmosphere. In this paper, we show that these hiss waves can be switched on by compressions of the magnetosphere which occur in response to similar to 1 hr long pressure structures in the solar wind. These structures originate at or near the Sun and are very common in the solar wind at 1 AU. The newly excited hiss waves scatter electrons into the atmosphere where they are observed on balloon-borne X-ray detectors. Our results suggest that magnetospheric models that predict the loss of electrons from hiss waves may be improved by consideration of solar wind pressure-driven dynamics.Peer reviewe

A Multiplexed Diagnostic Platform for Point-of-Care Pathogen Detection

We developed an automated point-of-care diagnostic instrument that is capable of analyzing nasal swab samples for the presence of respiratory diseases. This robust instrument, called FluIDx, performs autonomous multiplexed RT-PCR reactions that are analyzed by microsphere xMAP technology. We evaluated the performance of FluIDx, in comparison rapid tests specific for influenza and respiratory syncytial virus, in a clinical study performed at the UC Davis Medical Center. The clinical study included samples positive for RSV (n = 71), influenza A (n = 16), influenza B (n = 4), adenovirus (n = 5), parainfluenza virus (n = 2), and 44 negative samples, according to a composite reference method. FluIDx and the rapid tests detected 85.9% and 62.0% of the RSV positive samples, respectively. Similar sensitivities were recorded for the influenza B samples; whereas the influenza A samples were poorly detected, likely due to the utilization of an influenza A signature that did not accurately match currently circulating influenza A strains. Data for all pathogens were compiled and indicate that FluIDx is more sensitive than the rapid tests, detecting 74.2% (95% C.I. of 64.7-81.9%) of the positive samples in comparison to 53.6% (95% C.I. of 43.7-63.2%) for the rapid tests. The higher sensitivity of FluIDx was partially offset by a lower specificity, 77.3% versus 100.0%. Overall, these data suggest automated flow-through PCR-based instruments that perform multiplexed assays can successfully screen clinical samples for infectious diseases

Electron diffusion and advection during nonlinear interactions with whistler‐mode waves

Radiation belt codes evolve electron dynamics due to resonant wave‐particle interactions. It is not known how to best incorporate electron dynamics in the case of a wave power spectrum that varies considerably on a ‘sub‐grid' timescale shorter than the computational time‐step of the radiation belt model ΔtRBM, particularly if the wave amplitude reaches high values. Timescales associated with the growth rate of thermal instabilities are very short, and are typically much shorter than ΔtRBM. We use a kinetic code to study electron interactions with whistler‐mode waves in the presence of a thermally anisotropic background. For ‘low' values of anisotropy, instabilities are not triggered and we observe similar results to those obtained in Allanson et al. (2020, https://doi.org/10.1029/2020JA027949), for which the diffusion roughly matched the quasilinear theory over short timescales. For ‘high' levels of anisotropy, wave growth via instability is triggered. Dynamics are not well described by the quasilinear theory when calculated using the average wave power. Strong electron diffusion and advection occurs during the growth phase ( ≈ 100ms). These dynamics ‘saturate' as the wave power saturates at ≈ 1nT, and the advective motions dominate over the diffusive processes. The growth phase facilitates significant advection in pitch angle space via successive resonant interactions with waves of different frequencies. We suggest that this rapid advective transport during the wave growth phase may have a role to play in the electron microburst mechanism. This motivates future work on macroscopic effects of short‐timescale nonlinear processes in radiation belt modelling