Characterization of FOXSI Sounding Rocket Hard X-Ray Detectors Using Advanced Light Source at Berkeley

No abstract availabl

On the faintest solar coronal hard X-rays observed with FOXSI

Solar nanoflares are small eruptive events releasing magnetic energy in the quiet corona. If nanoflares follow the same physics as their larger counterparts, they should emit hard X-rays (HXRs) but with a rather faint intensity. A copious and continuous presence of nanoflares would deliver enormous amounts of energy into the solar corona, possibly accounting for its high temperatures. To date, there has not been any direct observation of such sustained and persistent HXRs from the quiescent Sun. However, Hannah et al. in 2010 constrained the quiet Sun HXR emission using almost 12 days of quiescent solar-off-pointing observations by RHESSI. These observations set upper limits at $3.4\times 10^{-2}$ photons$^{-1}$ s$^{-1}$ cm$^{-2}$ keV$^{-1}$ and $9.5\times 10^{-4}$ photons$^{-1}$ s$^{-1}$ cm$^{-2}$ keV$^{-1}$ for the 3-6 keV and 6-12 keV energy ranges, respectively. Observing feeble HXRs is challenging because it demands high sensitivity and dynamic range instruments in HXRs. The Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket experiment excels in these two attributes. Particularly, FOXSI completed its third successful flight (FOXSI-3) on September 7th, 2018. During FOXSI-3's flight, the Sun exhibited a fairly quiet configuration, displaying only one aged non-flaring active region. Using the entire $\sim$6.5 minutes of FOXSI-3 data, we constrained the quiet Sun emission in HXRs. We found $2\sigma$ upper limits in the order of $\sim 10^{-3}$ photons$^{-1}$ s$^{-1}$ cm$^{-2}$ keV$^{-1}$ for the 5-10 keV energy range. FOXSI-3's upper limit is consistent with what was reported by Hannah et al., 2010, but FOXSI-3 achieved this result using $\sim$1/2640 less time than RHESSI. A possible future spacecraft using FOXSI's concept would allow enough observation time to constrain the current HXR quiet Sun limits further or perhaps even make direct detections

Mass Transfer of Oxygen and Power Consumption with Highly Viscous Liquid in Gas-Liquid Agitated Vessel

The gas-liquid mass transfer volumetric coefficient (KLa) and power consumption under aeration are important parameters for designing gas-liquid agitated vessel. In this work, KLawas calculated by measuring the dissolved oxygen concentration and the mixing power consumption was calculated by measuringshaft torque in the aerated mixing vessel equipped with several types of large paddle impeller. It was found that the aerated mixing power consumption with the large paddle impellers did not decrease largely, because the large cavity was not formed behind the impeller blade. Then, KLa of large paddle impellers used was correlated with a modified equation of Sato et al. The intercept of Sato’s equation was correlated with the viscosity of CMC aqueous solution. KLaof large paddle impellers is estimated by using the modified Sato’s equation over a wide range of viscosity

Mass Transfer of Oxygen and Power Consumption with Highly Viscous Liquid in Gas-Liquid Agitated Vessel

The gas-liquid mass transfer volumetric coefficient (KLa) and power consumption under aeration are important parameters for designing gas-liquid agitated vessel. In this work, KLawas calculated by measuring the dissolved oxygen concentration and the mixing power consumption was calculated by measuringshaft torque in the aerated mixing vessel equipped with several types of large paddle impeller. It was found that the aerated mixing power consumption with the large paddle impellers did not decrease largely, because the large cavity was not formed behind the impeller blade. Then, KLa of large paddle impellers used was correlated with a modified equation of Sato et al. The intercept of Sato’s equation was correlated with the viscosity of CMC aqueous solution. KLaof large paddle impellers is estimated by using the modified Sato’s equation over a wide range of viscosity

Radon exhalation from soils in the subtropical region of Japan

The Third Asian and Oceanic Congree on Radiation Protectio