Periodicities in the Daily Proton Fluxes from 2011 to 2019 Measured by the Alpha Magnetic Spectrometer on the International Space Station from 1 to 100 GV

We present the precision measurement of the daily proton fluxes in cosmic rays from May 20, 2011 to October 29, 2019 (a total of 2824 days or 114 Bartels rotations) in the rigidity interval from 1 to 100 GV based on 5.5×109 protons collected with the Alpha Magnetic Spectrometer aboard the International Space Station. The proton fluxes exhibit variations on multiple timescales. From 2014 to 2018, we observed recurrent flux variations with a period of 27 days. Shorter periods of 9 days and 13.5 days are observed in 2016. The strength of all three periodicities changes with time and rigidity. The rigidity dependence of the 27-day periodicity is different from the rigidity dependences of 9-day and 13.5-day periods. Unexpectedly, the strength of 9-day and 13.5-day periodicities increases with increasing rigidities up to ∼10 GV and ∼20 GV, respectively. Then the strength of the periodicities decreases with increasing rigidity up to 100 GV.</p

Easy approach to synthesize N/P/K co-doped porous carbon microfibers from cane molasses as a high performance supercapacitor electrode material

In this study, we demonstrate a simple and low cost method to synthesize N/P/K co doped porous carbon microfibers (CMFs) from a sugar-rich byproduct (cane molasses) as the precursor material. A two step method for the synthesis of N/P/K codoped porous CMFs involving electrospinning of precursor material followed by simple carbonization at various temperatures (773.15–1173.15 K) was successfully applied. The N/P/K codoped porous CMFs exhibited high specific surface area (~580 m2 g1) and hierarchical porous structure. The potential application of N/P/K codoped porous CMFs as supercapacitor electrodes was investigated in a two electrode configuration employing aqueous K2SO4 solution and ionic liquids/acetonitrile (ILs/ACN) mixtures as the electrolytes. A series of electrochemical measurements include cyclic voltammetry, galvanostatic charge discharge and cycling durability all confirmed that the CMF 1073.15 supercapacitor exhibited good electrochemical performance with a specific capacitance of 171.8 F g1 at a current load of 1 A g1 measured in 1.5 M tetraethylammonium tetra fluoroborate (TEABF4)/ACN electrolyte, which can be charged and discharged up to a cell potential of 3.0 V. The specific energy density and power density of 53.7 W h kg1 and 0.84 kW kg1 were achieved. Furthermore, the CMF 1073.15 supercapacitor showed excellent cycling performance with capacitance retention of nearly 91% after 2500 charge discharge cycles, characterizing its electrochemical robustness and stable capacitive performanc

What drives women out of entrepreneurship? The joint role of testosterone and culture

The ratio of second to fourth digit (2D4D) has been shown to correlate negatively with entrepreneurial skills and financial success. We document that in a sample of entrepreneurs women have a lower 2D4D ratio than men, in sharp contrast with the features of the distribution in random samples. Exploiting variation across communities in indices correlated with women emancipation, we show that in regions where women are less emancipated their average DR is lower than that of men compared to regions with higher indices. This finding is consistent with the existence of gender related obstacles into entrepreneurship so that only women with well above average entrepreneurial skills find it attractive to self-select into entrepreneurship. This finding can rationalize three facts: a) fewer women than men are entrepreneurs; b) the proportion of women among entrepreneurs tends to be higher in countries with higher women emancipation; c) women who break the barrier into entrepreneurship seem to show more masculine traits. We also find that once women enter entrepreneurship, they are equally able than man to translate their ability into outcomes for the firm.

A facile and green preparation of durian shell-derived carbon electrodes for electrochemical double-layer capacitors

A facile and green preparation of high surface area activated carbons with mixed microporosity and mesoporosity from durian shell waste is reported in this work. The pore structure and surface chemistry of the parent carbon were modified by the combination of ultrasonication and microwave irradiation techniques. The effects of temperature and time in the ultrasonication treatment and power output and time in the microwave irradiation were studied. The electrochemical performance of carbon electrodes for supercapacitors was tested by cyclic voltammeter (CV) and galvanostatic charge–discharge. The results show that the capacitive energy storage of electrodes is critically dependent on the microporosity and surface chemistry of activated carbons. The highest electrode capacitance in this work was 103.6 F/g that prepared from activated carbon modified at an ultrasonication temperature of 323.15 K for 10 min and microwave power output of 900 W for 10 min