BatteryLab: A collaborative platform for power monitoring https://batterylab.dev

Advances in cloud computing have simplified the way that both software development and testing are performed. This is not true for battery testing for which state of the art test-beds simply consist of one phone attached to a power meter. These test-beds have limited resources, access, and are overall hard to maintain; for these reasons, they often sit idle with no experiment to run. In this paper, we propose to share existing battery testbeds and transform them into vantage points of BatteryLab, a power monitoring platform offering heterogeneous devices and testing conditions. We have achieved this vision with a combination of hardware and software which allow to augment existing battery test-beds with remote capabilities. BatteryLab currently counts three vantage points, one in Europe and two in the US, hosting three Android devices and one iPhone 7. We benchmark BatteryLab with respect to the accuracy of its battery readings, system performance, and platform heterogeneity. Next, we demonstrate how measurements can be run atop of BatteryLab by developing the “Web Power Monitor” (WPM), a tool which can measure website power consumption at scale. We released WPM and used it to report on the energy consumption of Alexa’s top 1,000 websites across 3 locations and 4 devices (both Android and iOS)

Jervisite, NaScSi2O6: Optical data, morphology, Raman spectroscopy, and crystal chemistry

The crystal structure of jervisite, ideally NaScSi2O6, was refined using single-crystal X-ray data collected using a crystal from the Seula quarry (Baveno, Verbano-Cusio-Ossola province, Italy). The refinement was carried out in the C2/c space group giving the following unit-cell dimensions: a = 9.8478(2) angstrom, b = 9.0575(1) angstrom, c = 5.3409(3) angstrom, beta = 106.87(2)degrees, and V = 455.89(2) angstrom(3) for Z= 4. The previous crystal structure, refined using data from a synthetic analogue and a natural sample, was confirmed and conforms with that of aegirine. The bond-valence calculation and the refined occupancy of the M1 and M2 sites confirm the cation distribution adopted in the empirical formula. Raman spectroscopy and refractive index measurements were also performed, and the morphology was studied in order to provide a complete description of this Sc-bearing Na pyroxene