Neutrinos, Weak Interactions, and r-process Nucleosynthesis

Two of the key issues in understanding the neutron-to-proton ratio in a core-collapse supernova are discussed. One of these is the behavior of the neutrino-nucleon cross sections as supernova energies. The other issue is the many-body properties of the neutrino gas near the core when both one- and two-body interaction terms are included.Comment: To be published in the Proceedings of "International Symposium on Structure of Exotic Nuclei and Nuclear Forces (SENUF 06)", March 2006, Tokyo, Japa

Simulation of the active Brownian motion of a microswimmer

Cataloged from PDF version of article.Unlike passive Brownian particles, active Brownian particles, also known as microswimmers, propel themselves with directed motion and thus drive themselves out of equilibrium. Understanding their motion can provide insight into out-of-equilibrium phenomena associated with biological examples such as bacteria, as well as with artificial microswimmers. We discuss how to mathematically model their motion using a set of stochastic differential equations and how to numerically simulate it using the corresponding set of finite difference equations both in homogenous and complex environments. In particular, we show how active Brownian particles do not follow the Maxwell-Boltzmann distribution-a clear signature of their out-of-equilibrium nature- and how, unlike passive Brownian particles, microswimmers can be funneled, trapped, and sorted. (C) 2014 American Association of Physics Teachers

Discovery of VHE and HE emission from the blazar 1ES 0414+009 with H.E.S.S and Fermi-LAT

The high energy peaked BL Lac (HBL) object 1ES 0414+009 (z=0.287) is a distant very high-energy (VHE, E > 100 GeV) blazars with well-determined redshift. This source was detected with the High Energy Stereoscopic System (H.E.S.S.) between October 2005 and September 2009. It was also detected with the Fermi Large Area Telescope (LAT) in 21 months of data. The combined high energy (HE) and VHE spectra, once corrected for gamma-gamma absorption on the extragalactic background light (EBL), indicate a Compton peak located above few TeV, among the highest in the BL Lac class.Comment: proceeding from the 25th Texas Symposium on Relativistic Astrophysics (Heidelberg, Germany, 2010

Recovery of metals and valuable chemicals from waste electric and electronic materials: a critical review of existing technologies

The growing development of technology has increased the amount of waste generated by electrical and electronic equipment (WEEE) every year. WEEE contains valuable metals and hazardous materials which, if not properly recovered, may drastically contribute to the depletion of natural resources while posing threat to the environment. The recent escalation of geopolitical tensions has fueled a growing spike in commodity and energy prices. In today's world, the recycling technologies have already evolved from primitive methods to more sophisticated techniques such as automatic disassembly, chemical leaching, electrolysis and so on. It is mandatory that researchers will develop novel technologies to tackle the complexity of WEEE treatment and material recovery. This analysis critically reviews the accomplishments in the field of e-waste recycling and further assesses the principles of recycling, separation, and optimized parameters of different technologies. The application of conventional techniques like pyrometallurgy and chemical leaching (non-cyanide, reduced wastewater) results in an active recovery of various materials. Compared to cyanide and strong acid leading, thiourea and thiosulphate have achieved significant advancements in environmental protection. Additionally, novel technologies like bio-metallurgy cryo-milling, siderophores and supercritical extraction technology also resulted in enhanced recovery efficiencies for base and precious metals, along with metal recovery techniques using recyclable lixiviates. However, the application of these technologies is restricted due to the heterogeneous nature of WEEE. Therefore, this review focuses on the deficiencies of each of them and further discusses the interpretation of future urgent developments in the WEEE recycling sector

Low energy neutrino scattering measurements at future Spallation Source facilities

In the future several Spallation Source facilities will be available worldwide. Spallation Sources produce large amount of neutrinos from decay-at-rest muons and thus can be well adapted to accommodate state-of-the-art neutrino experiments. In this paper low energy neutrino scattering experiments that can be performed at such facilities are reviewed. Estimation of expected event rates are given for several nuclei, electrons and protons at a detector located close to the source. A neutrino program at Spallation Sources comprises neutrino-nucleus cross section measurements relevant for neutrino and core-collapse supernova physics, electroweak tests and lepton-flavor violation searches.Comment: 12 pages, 4 figures, 5 table