User's manual for PRESTO: A computer code for the performance of regenerative steam turbine cycles

Standard turbine cycles for baseload power plants and cycles with such additional features as process steam extraction and induction and feedwater heating by external heat sources may be modeled. Peaking and high back pressure cycles are also included. The code's methodology is to use the expansion line efficiencies, exhaust loss, leakages, mechanical losses, and generator losses to calculate the heat rate and generator output. A general description of the code is given as well as the instructions for input data preparation. Appended are two complete example cases

A new HCN maser in IRAS 15082-4808

We have identified a new vibrational HCN maser at 89.087 GHz in the asymptotic giant branch (AGB) star IRAS 15082-4808, a maser which is thought to trace the innermost region of an AGB envelope. The observations of this maser at three epochs are presented: two positive detections and one null detection. The line profile has varied between the positive detections, as has the intensity of the maser. The major component of the maser is found to be offset by -2.0+/-0.9 km/s with respect to the systemic velocity of the envelope, as derived from the 88.631 GHz transition of HCN. Similar blueshifts are measured in the other 9 sources where this maser has been detected. Maser variability with pulsation phase has been investigated for the first time using the 10 stars now available. Comparisons with AGB model atmospheres constrain the position of the formation region of the maser to the region between the pulsation shocks and the onset of dust acceleration, between 2 and 4 stellar radii.Comment: 11 pages, 10 figures, accepted MNRAS, minor correction to equation

Neutrino-Neutrino Scattering and Matter-Enhanced Neutrino Flavor Transformation in Supernovae

We examine matter-enhanced neutrino flavor transformation ($\nu_{\tau(\mu)}\rightleftharpoons\nu_e$) in the region above the neutrino sphere in Type II supernovae. Our treatment explicitly includes contributions to the neutrino-propagation Hamiltonian from neutrino-neutrino forward scattering. A proper inclusion of these contributions shows that they have a completely negligible effect on the range of $\nu_e$-$\nu_{\tau(\mu)}$ vacuum mass-squared difference, $\delta m^2$, and vacuum mixing angle, $\theta$, or equivalently $\sin^22\theta$, required for enhanced supernova shock re-heating. When neutrino background effects are included, we find that $r$-process nucleosynthesis from neutrino-heated supernova ejecta remains a sensitive probe of the mixing between a light $\nu_e$ and a $\nu_{\tau(\mu)}$ with a cosmologically significant mass. Neutrino-neutrino scattering contributions are found to have a generally small effect on the $(\delta m^2,\ \sin^22\theta)$ parameter region probed by $r$-process nucleosynthesis. We point out that the nonlinear effects of the neutrino background extend the range of sensitivity of $r$-process nucleosynthesis to smaller values of $\delta m^2$.Comment: 38 pages, tex, DOE/ER/40561-150-INT94-00-6

Investigating early agriculture, plant use and culinary practices at Neolithic Jarmo (Iraqi Kurdistan)

The site of Jarmo in Iraqi Kurdistan has yielded key archaeological evidence which supports its interpretation as a large PPNB village. As such, it is the perfect candidate for the study of early agriculture, plant uses, food preparation and cooking practices. In order to explore these, new excavations and intensive sampling and flotation for the recovery of archaeobotanical remains were carried out in 2012 and 2014. This study presents the results from the analysis of the newly recovered archaeobotanical assemblage from Jarmo which has provided invaluable information about early crop agriculture and plant use. Furthermore, the in-depth study of recovered remains of archaeological food by high-resolution microscopy has shed light on culinary traditions and dietary choices during the Neolithic in the Central Zagros Area

Modulus Computational Entropy

The so-called {\em leakage-chain rule} is a very important tool used in many security proofs. It gives an upper bound on the entropy loss of a random variable $X$ in case the adversary who having already learned some random variables $Z_{1},\ldots,Z_{\ell}$ correlated with $X$, obtains some further information $Z_{\ell+1}$ about $X$. Analogously to the information-theoretic case, one might expect that also for the \emph{computational} variants of entropy the loss depends only on the actual leakage, i.e. on $Z_{\ell+1}$. Surprisingly, Krenn et al.\ have shown recently that for the most commonly used definitions of computational entropy this holds only if the computational quality of the entropy deteriorates exponentially in $|(Z_{1},\ldots,Z_{\ell})|$. This means that the current standard definitions of computational entropy do not allow to fully capture leakage that occurred "in the past", which severely limits the applicability of this notion. As a remedy for this problem we propose a slightly stronger definition of the computational entropy, which we call the \emph{modulus computational entropy}, and use it as a technical tool that allows us to prove a desired chain rule that depends only on the actual leakage and not on its history. Moreover, we show that the modulus computational entropy unifies other,sometimes seemingly unrelated, notions already studied in the literature in the context of information leakage and chain rules. Our results indicate that the modulus entropy is, up to now, the weakest restriction that guarantees that the chain rule for the computational entropy works. As an example of application we demonstrate a few interesting cases where our restricted definition is fulfilled and the chain rule holds.Comment: Accepted at ICTS 201

Characterizing precursors to stellar clusters with Herschel

Context. Despite their profound effect on the universe, the formation of massive stars and stellar clusters remains elusive. Recent advances in observing facilities and computing power have brought us closer to understanding this formation process. In the past decade, compelling evidence has emerged that suggests infrared dark clouds (IRDCs) may be precursors to stellar clusters. However, the usual method for identifying IRDCs is biased by the requirement that they are seen in absorption against background mid-IR emission, whereas dust continuum observations allow cold, dense pre-stellar-clusters to be identified anywhere. Aims: We aim to understand what dust temperatures and column densities characterize and distinguish IRDCs, to explore the population of dust continuum sources that are not IRDCs, and to roughly characterize the level of star formation activity in these dust continuum sources. Methods: We use Hi-GAL 70 to 500 $m data to identify dust continuum sources in the ell = 30deg and ell = 59deg Hi-GAL science demonstration phase (SDP) fields, to characterize and subtract the Galactic cirrus emission, and perform pixel-by-pixel modified blackbody fits on cirrus-subtracted Hi-GAL sources. We utilize archival Spitzer data to indicate the level of star-forming activity in each pixel, from mid-IR-dark to mid-IR-bright. Results: We present temperature and column density maps in the Hi-GAL ell = 30deg and ell = 59deg SDP fields, as well as a robust algorithm for cirrus subtraction and source identification using Hi-GAL data. We report on the fraction of Hi-GAL source pixels which are mid-IR-dark, mid-IR-neutral, or mid-IR-bright in both fields. We find significant trends in column density and temperature between mid-IR-dark and mid-IR-bright pixels; mid-IR-dark pixels are about 10 K colder and have a factor of 2 higher column density on average than mid-IR-bright pixels. We find that Hi-GAL dust continuum sources span a range of evolutionary states from pre- to star-forming, and that warmer sources are associated with more star formation tracers. Additionally, there is a trend of increasing temperature with tracer type from mid-IR-dark at the coldest, to outflow/maser sources in the middle, and finally to 8 and 24$m bright sources at the warmest. Finally, we identify five candidate IRDC-like sources on the far-side of the Galaxy. These are cold (20 K), high column density (N(H$_2$) gt 10$^22$ cm$^-2$) clouds identified with Hi-GAL which, despite bright surrounding mid-IR emission, show little to no absorption at 8 $m. These are the first inner Galaxy far-side candidate IRDCs of which the authors are aware. Herschel in an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation by NASA.The FITS files discussed in the paper would be released publicly WITH the Hi-GAL data (on the Hi-GAL website) when the Hi-GAL data is released publicly.Peer reviewe

The Otterbein Miscellany - June 1966

https://digitalcommons.otterbein.edu/miscellany/1012/thumbnail.jp