936 research outputs found
Surveying the SO(10) Model Landscape: The Left-Right Symmetric Case
Grand Unified Theories (GUTs) are a very well motivated extensions of the
Standard Model (SM), but the landscape of models and possibilities is
overwhelming, and different patterns can lead to rather distinct
phenomenologies. In this work we present a way to automatise the model building
process, by considering a top to bottom approach that constructs viable and
sensible theories from a small and controllable set of inputs at the high
scale. By providing a GUT scale symmetry group and the field content, possible
symmetry breaking paths are generated and checked for consistency, ensuring
anomaly cancellation, SM embedding and gauge coupling unification. We emphasise
the usefulness of this approach for the particular case of a non-supersymmetric
SO(10) model with an intermediate left-right symmetry and we analyse how
low-energy observables such as proton decay and lepton flavour violation might
affect the generated model landscape.Comment: 36 pages, 6 figure
Compressed and Split Spectra in Minimal SUSY SO(10)
The non-observation of supersymmetric signatures in searches at the Large
Hadron Collider strongly constrains minimal supersymmetric models like the
CMSSM. We explore the consequences on the SUSY particle spectrum in a minimal
SO(10) with large D-terms and non-universal gaugino masses at the GUT scale.
This changes the sparticle spectrum in a testable way and for example can
sufficiently split the coloured and non-coloured sectors. The splitting
provided by use of the SO(10) D-terms can be exploited to obtain light first
generation sleptons or third generation squarks, the latter corresponding to a
compressed spectrum scenario.Comment: 35 pages, 10 figures, published versio
Double Beta Decay, Lepton Flavour Violation and Collider Signatures of Left-Right Symmetric Models with Spontaneous D Parity Breaking
We propose a class of left-right symmetric models (LRSMs) with spontaneous D
parity breaking, where SU(2)_R breaks at the TeV scale while discrete
left-right symmetry breaks around 10^9 GeV. By embedding this framework in a
non-supersymmetric SO(10) Grand Unified Theory (GUT) with Pati-Salam symmetry
as the highest intermediate breaking step, we obtain g_R / g_L ~ 0.6 between
the right- and left-handed gauge couplings at the TeV scale. This leads to a
suppression of beyond the Standard Model phenomena induced by the right-handed
gauge coupling. Here we focus specifically on the consequences for neutrinoless
double beta decay, low energy lepton flavour violation and LHC signatures due
to the suppressed right handed currents. Interestingly, the reduced g_R allows
us to interpret an excess of events observed recently in the range of 1.9 TeV
to 2.4 TeV by the CMS group at the LHC as the signature of a right handed gauge
boson in LRSMs with spontaneous D parity breaking. Moreover, the reduced
right-handed gauge coupling also strongly suppresses the non-standard
contribution of heavy states to the neutrinoless double beta decay rate as well
as the amplitude of low energy lepton flavour violating processes. In a
dominant type-II Seesaw mechanism of neutrino mass generation, we find that
both sets of observables provide stringent and complimentary bounds which make
it challenging to observe the scenario at the LHC.Comment: 20 pages, 11 figure
Signal of Right-Handed Charged Gauge Bosons at the LHC?
We point out that the recent excess observed in searches for a right-handed
gauge boson W_R at CMS can be explained in a left-right symmetric model with D
parity violation. In a class of SO(10) models, in which D parity is broken at a
high scale, the left-right gauge symmetry breaking scale is naturally small,
and at a few TeV the gauge coupling constants satisfy g_R ~ 0.6 g_L. Such
models therefore predict a right-handed charged gauge boson W_R in the TeV
range with a suppressed gauge coupling as compared to the usually assumed
manifest left-right symmetry case g_R = g_L. The recent CMS data show excess
events which are consistent with the cross section predicted in the D parity
breaking model for 1.9 TeV < M_{W_R} < 2.4 TeV. If the excess is confirmed, it
would in general be a direct signal of new physics beyond the Standard Model at
the LHC. A TeV scale W_R would for example not only rule out SU(5) grand
unified theory models. It would also imply B-L violation at the TeV scale,
which would be the first evidence for baryon or lepton number violation in
nature and it has strong implications on the generation of neutrino masses and
the baryon asymmetry in the Universe.Comment: 4 pages, 2 figures, matches published versio
Implementation of Software Process Improvement Through TSPi in Very Small Enterprises
This article shows an experience in a very small enterprise related to improving software quality in terms of test and process productivity. A customized process from the current organizational process based on TSPi was defined and the team was trained on it. The pilot project had schedule and budget constraints. The process began by gathering historical data from previous projects in order to get a measurement repository. Then the project was launched and some metrics were collected. Finally, results were analyzed and the improvements verified
Approach to Identify Internal Best Practices in a Software Organization.
Current approaches to software process improvements (SPI) in software organizations is based on identifying gaps by comparing the way organizations work with respect to practices contained in the reference models. Later, these gaps will be targeted for establishing software process improvements. This paper presents an approach for identifying best practices within the organization. This is considered a key element in order to compare the way software organizations work with the reference models. After that, these practices will be complemented with practices contained in these models depending on the organization's business goals
Wake Analysis of an Aerodynamically Optimized Boxprop High Speed Propeller
The Boxprop is a novel, double-bladed, tip-joined propeller for high-speed flight. The concept draws inspiration from the box wing concept and could potentially decrease tip vortex strength compared with conventional propeller blades. Early Boxprop designs experienced significant amounts of blade interference. By performing a wake analysis and quantifying the various losses of the flow, it could be seen that these Boxprop designs produced 45% more swirl than a conventional reference blade. The reason for this was the proximity of the Boxprop blade halves to each other, which prevented the Boxprop from achieving the required aerodynamic loading on the outer parts of the blade. This paper presents an aerodynamic optimization of a 6-bladed Boxprop aiming at maximizing efficiency and thrust at cruise. A geometric parametrization has been adopted which decreases interference by allowing the blade halves to be swept in opposite directions. Compared with an earlier equal-thrust Boxprop design, the optimized design features a 7% percentage point increase in propeller efficiency and a lower amount of swirl and entropy generation. A vortex-like structure has also appeared downstream of the optimized Boxprop, but with two key differences relative to conventional propellers. (1) Its formation differs from a traditional tip vortex and (2) it is 46% weaker than the tip vortex of an optimized 12-bladed conventional propeller
An Optimization Platform for High Speed Propellers
To improve the efficiency by which current power plants translate jet energy into useful thrust the use of turboprop and in particular open rotor aircraft are being revisited. One challenge in association with developing new powerplants for such aircraft is high speed propeller design in general and noise prediction in particular.
The Boxprop was invented in 2009 by GKN Aerospace in order to mitigate the effects of the tip vortex on noise and to improve upon the aerodynamics of a conventional propeller blade. The Boxprop is composed of a double-bladed propeller joined at the tips, and the design has the potential to eliminate the tip vortex, and thereby decrease that particular noise source. The complex and highly three-dimensional shape of an advanced propeller blade is challenging to model with classical propeller design methods, requiring instead more sophisticated optimization methods.
This paper presents an optimization platform developed for high speed propellers, and illustrates its use by performing a reduced aerodynamic optimization of the Boxprop. The optimization process starts by performing a Latin Hypercube Sampling of the design space, and analyzes the resulting geometries using CFD. A meta-model employing radial basis functions is then used to interpolate on the obtained CFD results, which the GA uses to find optimal candidates along the obtained Pareto front. These designs are then evaluated using CFD, and their data added to the meta-model. The process iterates until the meta-model converges.
The results of this paper demonstrate the capability of the presented optimization platform, and applying it on the Boxprop has resulted in valuable design improvements and insights. The obtained designs show less blade interference, more efficiently loaded blades, and less produced swirl. The methodology for geometry generation, meshing and optimizing is fast, robust, and readily extendable to other types of optimization problems, and paves the way for future collaborative research in the area of turbomachinery
Calidad en el desarrollo de aplicaciones siguiendo la metodolofgia Team Software Process TSPi
Este artículo presenta un caso de estudio basado en la aplicación de TSPi. Los datos fueron obtenidos de 34 equipos de estudiantes de cuarto curso de la Facultad de Informática de la Universidad Politécnica de Madrid. Todos los equipos desarrollaron el mismo proyecto a lo largo de dos ciclos de desarrollo. Con los datos obtenidos, se ha realizado un análisis por fase del ciclo de vida de TSPi, con respecto a la desviación en la estimación de defectos, la densidad de defectos y la evolución del rendimiento de defectos. Finalmente, se presenta el análisis de los resultados, comparando ambos ciclos, así como propuestas de mejor
Hydrogen evolution reaction at lead/carbon porous electrodes studied by a novel electrochemical mass spectrometry set-up
Lead–acid batteries are robust, low-cost, and have a large power-to-weight ratio. Recently, small amounts of carbon-based materials with a high surface area have been included in the Pb electrode as additives to improve the high-rate partial state of charge. However, carbon-based materials also enhance the hydrogen evolution reaction during the charging process at the negative active material (NAM), which is undesirable and dangerous. Therefore, in the current communication, a promising differential electrochemical mass spectrometry (DEMS) set-up suitable for studying the hydrogen evolution reaction (HER) at technical NAM electrodes in lead–acid batteries (LABs) is reported for the first time.Fil: Mondino, Tomas Miguel. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: García, Gonzalo. Universidad de La Laguna; EspañaFil: Pastor, Elena. Universidad de La Laguna; EspañaFil: Fungo, Fernando Gabriel. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Planes, Gabriel Angel. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; Argentin
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