Phase evolution of Na2O–Al2O3–SiO2–H2O gels in synthetic aluminosilicate binders

This study demonstrates the production of stoichiometrically controlled alkali-aluminosilicate gels (‘geopolymers’) via alkali-activation of high-purity synthetic amorphous aluminosilicate powders. This method provides for the first time a process by which the chemistry of aluminosilicate-based cementitious materials may be accurately simulated by pure synthetic systems, allowing elucidation of physicochemical phenomena controlling alkali-aluminosilicate gel formation which has until now been impeded by the inability to isolate and control key variables. Phase evolution and nanostructural development of these materials are examined using advanced characterisation techniques, including solid state MAS NMR spectroscopy probing 29Si, 27Al and 23Na nuclei. Gel stoichiometry and the reaction kinetics which control phase evolution are shown to be strongly dependent on the chemical composition of the reaction mix, while the main reaction product is a Na2O–Al2O3–SiO2–H2O type gel comprised of aluminium and silicon tetrahedra linked via oxygen bridges, with sodium taking on a charge balancing function. The alkali-aluminosilicate gels produced in this study constitute a chemically simplified model system which provides a novel research tool for the study of phase evolution and microstructural development in these systems. Novel insight of physicochemical phenomena governing geopolymer gel formation suggests that intricate control over time-dependent geopolymer physical properties can be attained through a careful precursor mix design. Chemical composition of the main N–A–S–H type gel reaction product as well as the reaction kinetics governing its formation are closely related to the Si/Al ratio of the precursor, with increased Al content leading to an increased rate of reaction and a decreased Si/Al ratio in the N–A–S–H type gel. This has significant implications for geopolymer mix design for industrial applications

Astroparticle Physics with a Customized Low-Background Broad Energy Germanium Detector

The MAJORANA Collaboration is building the MAJORANA DEMONSTRATOR, a 60 kg array of high purity germanium detectors housed in an ultra-low background shield at the Sanford Underground Laboratory in Lead, SD. The MAJORANA DEMONSTRATOR will search for neutrinoless double-beta decay of 76Ge while demonstrating the feasibility of a tonne-scale experiment. It may also carry out a dark matter search in the 1-10 GeV/c^2 mass range. We have found that customized Broad Energy Germanium (BEGe) detectors produced by Canberra have several desirable features for a neutrinoless double-beta decay experiment, including low electronic noise, excellent pulse shape analysis capabilities, and simple fabrication. We have deployed a customized BEGe, the MAJORANA Low-Background BEGe at Kimballton (MALBEK), in a low-background cryostat and shield at the Kimballton Underground Research Facility in Virginia. This paper will focus on the detector characteristics and measurements that can be performed with such a radiation detector in a low-background environment.Comment: Submitted to NIMA Proceedings, SORMA XII. 9 pages, 4 figure

Implementación de estrategias de marketing para la empresa Importaciones Generales Nieto S. R. L. - 2017

El mercado ferretero del distrito de Nueva Cajamarca (San Martín, Perú) se encuentra en constante crecimiento, ya que cada día se destinan más áreas a la agricultura, siendo esta actividad realizada por el 55% de los pobladores del distrito. Al incrementar las áreas utilizadas para a la agricultura genera mayor demanda de herramientas y equipos para uso agrícola y forestal, generando que nuevas ferreterías inicien sus actividades comerciales. Es por ello que Importaciones Generales Nieto S.R.L. tuvo la necesidad de implementar estrategias para generar la repetición de compra por parte de los consumidores. La investigación tuvo como objetivo la implementación de estrategias generadas por un plan de marketing para lograr la repetición de compra, de esa forma aumentar el volumen de ventas y la participación de mercado. Se realizó un análisis previo de la situación de la empresa, se estudió a profundidad a los competidores, se hizo un estudio detallado del mercado donde se determinó como público objetivo a las personas que se dedican a la agricultura. Se aplicó una encuesta que permitió recolectar datos para elaborar estrategias como merchandising y publicidad; que tuvieron como fin generar un impacto positivo para la empresa. La implementación de estrategias generadas por el plan de márketing tuvo un costo de S/.2,671.25 mensuales. Como resultados por la aplicación de las estrategias fue: Las ventas del mes de noviembre fueron de S/.196,063.18, que respecto a las ventas del mes de noviembre del 2016 que fueron S/.178,869.66 esto representa un crecimiento del 9.6% de ventas mensuales.Tesi

Search for Neutrinoless Double- β Decay in Ge 76 with the Majorana Demonstrator

The Majorana Collaboration is operating an array of high purity Ge detectors to search for neutrinoless double-β decay in Ge76. The Majorana Demonstrator comprises 44.1 kg of Ge detectors (29.7 kg enriched in Ge76) split between two modules contained in a low background shield at the Sanford Underground Research Facility in Lead, South Dakota. Here we present results from data taken during construction, commissioning, and the start of full operations. We achieve unprecedented energy resolution of 2.5 keV FWHM at Qββ and a very low background with no observed candidate events in 9.95 kg yr of enriched Ge exposure, resulting in a lower limit on the half-life of 1.9×1025 yr (90% C.L.). This result constrains the effective Majorana neutrino mass to below 240-520 meV, depending on the matrix elements used. In our experimental configuration with the lowest background, the background is 4.0-2.5+3.1 counts/(FWHM t yr)

Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 2: The Physics Program for DUNE at LBNF

The Physics Program for the Deep Underground Neutrino Experiment (DUNE) at the Fermilab Long-Baseline Neutrino Facility (LBNF) is described

The role of al in cross-linking of alkali-Activated slag cements

The structural development of a calcium (sodium) aluminosilicate hydrate (C-(N-)A-S-H) gel system, obtained through the reaction of sodium metasilicate and ground granulated blast furnace slag, is assessed by high-resolution 29Si and 27Al MAS NMR spectroscopy during the first 2 yr after mixing. The cements formed primarily consist of C-(N-)A-S-H gels, with hydrotalcite and disordered alkali aluminosilicate gels also identified in the solid product assemblages. Deconvolution of the 27Al MAS NMR spectra enables the identification of three distinct tetrahedral Al sites, consistent with the 29Si MAS NMR data, where Q3(1Al), Q4(3Al), and Q4(4Al) silicate sites are identified. These results suggest significant levels of cross-linking in the C-(N-)A-S-H gel and the presence of an additional highly polymerized aluminosilicate product. The mean chain length, extent of cross-linking, and Al/Si ratio of the C-(N-)A-S-H gel decrease slightly over time. The de-cross-linking effect is explained by the key role of Al in mixed cross-linked/non-cross-linked C-(N-)A-S-H gels, because the cross-linked components have much lower Al-binding capacities than the noncross-linked components. These results show that the aluminosilicate chain lengths and chemical compositions of the fundamental structural components in C-(N-)A-S-H gels vary in a way that is not immediately evident from the overall bulk chemistry

The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess