[en] The microstructural evolution of composites of SiC/Cu-Si alloys obtained through process of reactive infiltration to 1400 degree centigrade was studied. Three zones were detected in the obtained composites: the reaction zone, the transition zone and the infiltrated zone. In the reaction zone and transition zone the resulting microstructure was composed of a metallic phase, graphite laminae and SiC particles. It was found that SiC decomposes into these areas because of the alloy Cu-Si, so the available Si forms a liquid solution that a room temperature consisted of a a solid solution and a γ phase (Cu₅Si). The carbon resulting from the decomposition of SiC precipitated as graphite laminae. In addition, the SiC decomposition was decreasing as the initial amount of Si in the alloy increased. (Author) 37 refs.

[en] In the last decades, the irrigated agricultural areas have increased in Murcia, S. E. Spain, especially in the agrarian District Comarca del Campo de Cartagena. A consequence of this increase is the high use of fertilizers resulting to an excess of nutrients such as nitrogen. Another problem associated with the agricultural is the disposal of the increasing amount of organic agricultural residues from post-harvest practices. In this research we will study the effects of recycling crop residues as an organic fertilizer in vegetable production as a disposal management technique to reduce the amount of post-harvest residues. (Author) 9 refs.

[en] Graphical abstract: - Highlights: • Characterization of hexadimethrine-montmorillonite nanocomposite was appraised. • Comparative studies with traditional HDTMA-montmorillonite were performed. • We investigated the pesticide adsorption mechanisms displayed by the nanocomposites. • Hexadimethrine-nanocomposite showed selective affinity for anionic pesticides. - Abstract: The goal of this work was to prepare and characterize a novel functional material by the modification of SAz-1 montmorillonite with the cationic polymer hexadimethrine (SA-HEXAD), and to explore the potential use of this nanocomposite as a pesticide adsorbent. Comparative preparation and characterization with the well-known hexadecyltrimethylammonium-modified SAz-1 montmorillonite (SA-HDTMA) was also assessed. The characterization was performed by elemental analysis, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), physisorption of N_2, scanning electron microscopy (SEM) and Z potential measurements. The characterization and adsorption experiments showed that the extent of pesticide adsorption was markedly subjected to the structure and features of the surface of each organo-clay and also to the nature of the considered pesticide. SA-HEXAD displayed a high affinity for anionic pesticides which, presumably, were adsorbed by electrostatic attraction on positively-charged ammonium groups of the polymer not directly interacting with the clay. In contrast, SA-HDTMA displayed great adsorption of both uncharged and anionic pesticides with predominance of hydrophobic interactions. This work provided information about the surface properties of a new organic–inorganic nanohybrid material, SA-HEXAD, and its potential as an adsorbent for the removal of anionic organic pollutants from aqueous solutions

[en] The Qweak experiment measured the parity-violating asymmetry from elastic electron- proton scattering at Q2 = 0.025 (GeV/c)2. Using a 1.155 GeV/c 89% longitudinally polarized electron beam current of up to 180 μA incident on a 34.4 cm long high-powered liquid H2 cryotarget and a 9000 A torodial magnet selected out elastically scattered electrons that were then detected on an array of eight symmetrically placed Cerenkov detectors. The results from our commissioning period, which constitute approximately 4% of our data, have been published, where we report a parity violating asymmetry of Aep = -279 ± 35 (statistics) ± 31 (systematics) ppm. By combining the results of other Parity Violating Electron Scattering (PVES) experiments, we have precisely determined the weak charge of the proton (Qp w), and inclusion of Atomic Parity Violating Experiments (APV) allows for a determination of the neutron’s weak charge. During this talk I will detail the advantages of a PVES experiment, as well as the challenges we faced. I will also discuss our published results and what we expect to achieve after the analysis of our complete dataset.

[en] Cooling and detection schemes using laser cooling and methods of quantum logic can contribute to high precision CPT symmetry tests in the baryonic sector. This work introduces an experiment to sympathetically cool protons and antiprotons using the Coulomb interaction with a ion trapped in a nearby but separate potential well. We have designed and set up an apparatus to show such coupling between two identical ions for the first time in a Penning trap. In this paper, we present evidence for successful loading and Doppler cooling of clouds and single ions. Our coupling scheme has applications in a range of high-precision measurements in Penning traps and has the potential to substantially improve motional control in these experiments. (paper)

[en] We have performed a novel comparison between electron-beam polarimeters based on Moller and Compton scattering. A sequence of electron-beam polarization measurements were performed at low beam currents (< 5 μA) during the Q_w_e_a_k experiment in Hall C at Jefferson Lab. These low current measurements were bracketed by the regular high current (180 μA) operation of the Compton polarimeter. All measurements were found to be consistent within experimental uncertainties of 1% or less, demonstrating that electron polarization does not depend significantly on the beam current. This result lends confidence to the common practice of applying Moller measurements made at low beam currents to physics experiments performed at higher beam currents. Here, the agreement between two polarimetry techniques based on independent physical processes sets an important benchmark for future precision asymmetry measurements that require sub-1% precision in polarimetry.

[en] A special ion trap was initially built up to perform β-ν correlation experiments with radioactive ions. The trap geometry is also well suited to perform experiments with laser-cooled ions, serving for the development of a new type of Penning trap, in the framework of the project TRAPSENSOR at the University of Granada. The goal of this project is to use a single "4"0Ca"+ ion as detector for single-ion mass spectrometry. Within this project and without any modification to the initial electrode configuration, it was possible to perform Doppler cooling on "4"0Ca"+ ions, starting from large clouds and reaching single ion sensitivity. This new feature of the trap might be important also for other experiments with ions produced at radioactive ion beam facilities. In this publication, the trap and the laser system will be described, together with their performance with respect to laser cooling applied to large ion clouds down to a single ion

[en] The reactions ¹⁶O(e,e'p) ¹⁵N, ²⁰⁸Pb(e,e'p) ²⁰⁷Tl and ¹²C(e,e'p) ¹¹B were measured in experiments E00-102 and E06-007 performed at JLab (VA, USA) at true quasielastic kinematics (x_B = 1) with constant energy (ω) and momentum (q) transferred over a wide p_miss range. These experiments address several open issues in nuclear structure such as the role of relativity and of long-range correlations in the description of nuclei as well as a possible dependence of the spectroscopic factors on Q². Preliminary experimental results and theoretical predictions from a fully relativistic DWIA model carefully averaged over the experimental acceptances are shown.

[en] The expansion of FPGA technology in numerous application fields is a fact. Single Event Effects (SEE) are a critical factor for the reliability of FPGA based systems. For this reason, a number of researches have been studying fault tolerance techniques to harden different elements of FPGA designs. Using Partial Reconfiguration (PR) in conjunction with Triple Modular Redundancy (TMR) is an emerging approach in recent publications dealing with the implementation of fault tolerant processors on SRAM-based FPGAs. While these works pay great attention to the repair of erroneous instances by means of reconfiguration, the essential step of synchronizing the repaired processors is insufficiently addressed. In this context, this paper poses four different synchronization approaches for soft core processors, which balance differently the trade-off between synchronization speed and hardware overhead. All approaches are assessed in practice by synchronizing TMR protected PicoBlaze processors implemented on a Virtex-5 FPGA. Nevertheless all methods are of a general nature and can be applied for different processor architectures in a straightforward fashion. - Highlights: • Four different synchronization methods for faulty processors are proposed. • The methods balance between synchronization speed and hardware overhead. • They can be applied to TMR-protected reconfigurable FPGA designs. • The proposed schemes are implemented and tested in real hardware.

[en] Quasi elastic cross sections were measured for the first time for both negative and positive missing momenta for the ²⁰⁹Bi(e,e'p)²⁰⁸Pb reaction leading to the ground state and hole states of ²⁰⁸Pb. Experimental cross sections obtained between -0.3 GeV/c to 0.3 GeV/c agree with theoretical calculations using RDWIA techniques both in shape and magnitude for the ground state. The data for the ground state production of ²⁰⁸Pb are consistent with a theoretical model assuming a single proton(1.06 ± 0.10) in the 1h9/2 orbit in ²⁰⁹Bi.