51,480 research outputs found

    Spartan Daily, September 28, 2016

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    Volume 147, Issue 13https://scholarworks.sjsu.edu/spartan_daily_2016/1053/thumbnail.jp

    Ultracold chemical reactions of a single Rydberg atom in a dense gas

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    Within a dense environment (ρ≈1014 \rho \approx 10^{14}\,atoms/cm3^3) at ultracold temperatures (T<1 ΌKT < 1\,\mu{}\text{K}), a single atom excited to a Rydberg state acts as a reaction center for surrounding neutral atoms. At these temperatures almost all neutral atoms within the Rydberg orbit are bound to the Rydberg core and interact with the Rydberg atom. We have studied the reaction rate and products for nSnS 87^{87}Rb Rydberg states and we mainly observe a state change of the Rydberg electron to a high orbital angular momentum ll, with the released energy being converted into kinetic energy of the Rydberg atom. Unexpectedly, the measurements show a threshold behavior at n≈100n\approx 100 for the inelastic collision time leading to increased lifetimes of the Rydberg state independent of the densities investigated. Even at very high densities (ρ≈4.8×1014 cm−3\rho\approx4.8\times 10^{14}\,\text{cm}^{-3}), the lifetime of a Rydberg atom exceeds 10 Όs10\,\mu\text{s} at n>140n > 140 compared to 1 Όs1\,\mu\text{s} at n=90n=90. In addition, a second observed reaction mechanism, namely Rb2+_2^+ molecule formation, was studied. Both reaction products are equally probable for n=40n=40 but the fraction of Rb2+_2^+ created drops to below 10 \,% for n≄90n\ge90.Comment: 13 pages, 13 figure

    Spartan Daily, March 26, 2019

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    Volume 152, Issue 26https://scholarworks.sjsu.edu/spartan_daily_2019/1025/thumbnail.jp

    The New Hampshire, Vol. 105, No. 25 (Feb. 1, 2016)

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    An independent student produced newspaper from the University of New Hampshire

    Love is in the Airwaves: Contesting Mass Incarceration with Prisoners\u27 Radio

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    Building on bell hooks’ conceptualization of love as a mode of political resistance, this article explores how prisoners’ radio employs love to combat injustice. Through an examination of two prisoners’ radio projects—The Prison Show in Texas and Restorative Radio in Kentucky—I argue that incarcerated people and their loved ones appropriate the radio to perform public and revolutionary acts of love, countering the oppressive forces of mass incarceration in the United States. By unapologetically positioning their love for prisoners front and center, ordinary Americans subvert systems of oppression which mark incarcerated folks as incapable and unworthy of love. Love is an intrinsic marker of humanity, so prisoners’ radio allows the incarcerated and their advocates on the outside to actively challenge the dehumanization that people face behind bars

    Algae Biofuel Triacylglyceride Transesterification Optimization

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    Algae biofuels may hold the key to solving the problem of fossil fuel consumption by being comparable in content, renewable, and carbon-neutral. Many biofuel researchers and corporations have undertaken to increase the production rate or capacity of triacylglycerides (TAG), the fat precursor to biodiesel fuel produced by algae, in algae cultures and published articles documenting their findings. This research is devoted to evaluating the effect of water that may be present in samples on the conversion efficiency of TAG into fatty acid methyl esters (FAME), commonly referred to as biodiesel. Therefore, that efficiency was studied to find the water content which optimizes the yield and determine if further drying of algae was necessary as an additional step in sample preparation. The results showed that the water content typically present in lyophilized algae samples is not sufficient to appreciably inhibit the reaction efficiency and necessitate extensive drying as a sample preparation step prior to transesterification

    A comparison of univariate methods for forecasting electricity demand up to a day ahead

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    This empirical paper compares the accuracy of six univariate methods for short-term electricity demand forecasting for lead times up to a day ahead. The very short lead times are of particular interest as univariate methods are often replaced by multivariate methods for prediction beyond about six hours ahead. The methods considered include the recently proposed exponential smoothing method for double seasonality and a new method based on principal component analysis (PCA). The methods are compared using a time series of hourly demand for Rio de Janeiro and a series of half-hourly demand for England and Wales. The PCA method performed well, but, overall, the best results were achieved with the exponential smoothing method, leading us to conclude that simpler and more robust methods, which require little domain knowledge, can outperform more complex alternatives
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