Minimal supergravity radiative effects on the tri-bimaximal neutrino mixing pattern

We study the stability of the Harrison-Perkins-Scott (HPS) mixing pattern, assumed to hold at some high energy scale, against supersymmetric radiative corrections. We work in the framework of a reference minimal supergravity model (mSUGRA) where supersymmetry breaking is universal and flavor-blind at unification. The radiative corrections considered include both RGE running as well as threshold effects. We find that in this case the solar mixing angle can only increase with respect to the HPS reference value, while the atmospheric and reactor mixing angles remain essentially stable. Deviations from the solar angle HPS prediction towards lower values would signal novel contributions from physics beyond the simplest mSUGRA model.Comment: 13 pages, 3 figures; added reference; final version for publicatio

Predicting Neutrinoless Double Beta Decay

We give predictions for the neutrinoless double beta decay rate in a simple variant of the A_4 family symmetry model. We show that there is a lower bound for the neutrinoless double beta decay amplitude even in the case of normal hierarchical neutrino masses, corresponding to an effective mass parameter |m_{ee}| >= 0.17 \sqrt{\Delta m^2_{ATM}}. This result holds both for the CP conserving and CP violating cases. In the latter case we show explicitly that the lower bound on |m_{ee}| is sensitive to the value of the Majorana phase. We conclude therefore that in our scheme, neutrinoless double beta decay may be accessible to the next generation of high sensitivity experiments.Comment: 4 pages, 5 figures, 1 tabl

Heavy Majorana Neutrinos in the Effective Lagrangian Description: Application to Hadron Colliders

We consider the effects of heavy Majorana neutrinos N with sub-TeV masses. We argue that the mere presence of these particles would be a signal of physics beyond the minimal seesaw mechanism and their interactions are, therefore, best described using an effective Lagrangian. We then consider the complete set of leading effective operators (up to dimension 6) involving the N and Standard Model fields and show that these interactions can be relatively easy to track at high-energy colliders. For example, we find that an exchange of a TeV-scale heavy vector field can yield thousands of characteristic same-sign lepton number violating l^+ l^+ j j events (j=light jet) at the LHC if m_N < 600 GeV, which can also have a distinctive forward-backward asymmetry signal; even the Tevatron has good prospects for this signature if m_N < 300 GeV.Comment: 4 pages, 1 figur

APC fly ash recycling: development of a granular material from laboratory to a pilot scale

The aim of this article is to present the research carried out over a 10 year period to develop an environmentally safe method for recycling Air Pollution Control (APC) residues. The initial studies aimed to formulate a mixture of Weathered Bottom Ash (WBA), APC residues and Portland Cement (PC) to be used as a sub-base in road constructions. Mechanical performance was subsequently enhanced by preparing a mortar prior to mixing it with WBA in order to obtain a granular material. After testing different formulations, the optimum mortar consisted of 50% APC residues and 50% PC. The evaluation was carried out based on the concentration release of the heavy metals and metalloids included in the Catalan legislation for revalorization of residues. After the applicability of the granular material was successfully demonstrated at laboratory scale from an environmental and mechanical point of view, a pilot scale plant was designed in order to assess its performance in a real scenario during four month. Thus, three roads were built: two containing 100% granular material and a third containing 100% WBA. The results showed that the immobilisation of all toxic species from APC residues is accomplished by the pozzolanic effect of the cement. The WBA, APC, and PC proportions show to be the most appropriate for compliance with regard to environmental and mechanics requirements

Non-Abelian Discrete Symmetries and Neutrino Masses: Two Examples

Two recent examples of non-Abelian discrete symmetries (S_3 and A_4) in understanding neutrino masses and mixing are discussed.Comment: 16 pages, no figure, invited contribution to NJP focus issue on neutrino

Aggregate material formulated with MSWI bottom ash and APC fly ash for use as secondary building material

The main goal of this paper is to obtain a granular material formulated with Municipal Solid Waste Incinerarion (MSWI) bottom ash (BA) and air pollution control (APC) ash to be used as secondary building material. Previously, an optimum concrete mixture using both MSWI residues as aggregates was formulated. A compromise between the environmental behaviour and the economy of the process was considered. Unconfined compressive strength and abrasion resistance values were measured in order to evaluate the mechanical properties. From these results, the granular mixture was not suited for certain applications owing to the high BA/APC content and low cement percentages used to reduce the costs of the final product. Nevertheless, the leaching test performed showed that the concentrations of all heavy metals were below the limits established by the current Catalan legislation for their reutilization. Therefore, the material studied might be mainly used in embankments, where high mechanical properties are not needed and environmental safety is assured

Neutrino physics beyond neutrino masses

We briefly summarise the current status of neutrino masses and mixing, paying special attention to the prospects for observing new leptonic interactions.Comment: Latex 6 pages. To appear in the proceedings of 9th Hellenic School and Workshops on Elementary Particle Physics and Gravity (CORFU2009), Corfu, Greece, August 30-September 20, 2009

MSWI bottom ash for thermal energy storage: An innovative and sustainable approach for its reutilization

The management of Municipal Solid Waste (MSW) is a very important issue that must be dealt by the perspective of the 3 Rs (Reuse, reduce, recycle. MSW incineration bottom ash (BA) accounts for 85-95% of the total solids that remained after incineration. Finding suitable alternatives for its revalorization is very attractive, especially in terms of environmental sustainability. Thermal energy storage (TES) is a complementary technology of renewable energy. The aim of this study is to evaluate the thermophysical properties of weathered BA (WBA) in order to find suitable alternatives for its valorisation. Several samples of WBA were collected from a waste-to-energy facility located in Tarragona (Spain). This facility sieved to different size fractions. Each size fraction was characterized with respect its physicochemical properties and the energy density (ren) was calculated. The results obtained showed that this residue is a suitable alternative candidate material for TES as it presents an energy density of 1461.2 kJ m 3 K 1 for the 1-2 mm fraction. In addition, the low cost of this type of residue (0.6V per t) and its high production rate per year makes it an attractive and sustainable alternative for TES

Low-grade magnesium oxide by-products for environmental solutions: characterization and geochemical performance

The reutilization of the by-products from the calcination of natural magnesite for environmental solutions is conditioned by the availability of MgO, CaO and other compounds. In order to overcome their great heterogeneity, an exhaustive chemical and physical characterization is necessary in order to assess their potential applications. In this study, the acid neutralization capacity (ANC) test was used to categorize three types of by-products (LG-MgO, LG-D and LG-F), which mainly differed according to source ore and processing conditions. The experimental data concerning the leaching of Mg2 +, Ca2 +, Fe2 + and SO42 − was corroborated with geochemical predictions using the modelling software Visual MINTEQ. Likewise, the main solubility-controlling mineral phases were also identified. According to the results, there is a buffer capacity within the pH 8 10 range, mainly dominated by the neutralization of MgO/Mg(OH)2, equilibrium with a small contribution from the carbonate content at lower pH values. The release of sulphates showed a non-pH dependency attributed to the solubility of CaSO4 and elemental sulphur present in petcoke. For dust materials, leaching of Fe was minimal above pH 6 owing to the insoluble nature of the Fe2O3/Fe3O4 pair. Accordingly, the by-products labeled as LG-D and LG-F are better suited for stabilizing solid wastes or wastewater that are acid while LG-MgO is more appropriate for alkaline residues such as contaminated soils. In both cases, a suitable pH range in which pH-dependent heavy metals and metalloids show minimum solubility can be obtained. The use of these by-products guarantees an environmentally friendly alkali reservoir for the long-term stabilization of heavy metals and metalloids at a very competitive price as a substitute for the widely used lim

Use of weathered and fresh bottom ash mix layers as a subbase in road constructions: environmental behavior enhancement by means of a retaining barrier

The presence of neoformed cement-like phases during the weathering of non-stabilized freshly quenched bottom ash favours the development of a bound pavement material with improved mechanical properties. Use of weathered and freshly quenched bottom ash mix layers placed one over the other allowed the retention of leached heavy metals and metalloids by means of a reactive percolation barrier. The addition of 50% of weathered bottom ash to the total subbase content diminished the release of toxic species to below environmental regulatory limits. The mechanisms of retention and the different processes and factors responsible of leaching strongly depended on the contaminant under concern as well as on the chemical and physical factors. Thus, the immediate reuse of freshly quenched bottom ash as a subbase material in road constructions is possible, as both the mechanical properties and long-term leachability are enhanced