5,321 research outputs found
Beyond the Standard Model for Montaneros
These notes cover (i) electroweak symmetry breaking in the Standard Model
(SM) and the Higgs boson, (ii) alternatives to the SM Higgs boson including an
introduction to composite Higgs models and Higgsless models that invoke extra
dimensions, (iii) the theory and phenomenology of supersymmetry, and (iv)
various further beyond topics, including Grand Unification, proton decay and
neutrino masses, supergravity, superstrings and extra dimensions.Comment: Based on lectures by John Ellis at the 5th CERN-Latin-American School
of High-Energy Physics, Recinto Quirama, Colombia, 15 - 28 Mar 2009, 84
pages, 35 figure
Quadratic invariants for discrete clusters of weakly interacting waves
We consider discrete clusters of quasi-resonant triads arising from a Hamiltonian three-wave equation. A cluster consists of N modes forming a total of M connected triads. We investigate the problem of constructing a functionally independent set of quadratic constants of motion. We show that this problem is equivalent to an underlying basic linear problem, consisting of finding the null space of a rectangular M Ă N matrix with entries 1, â1 and 0. In particular, we prove that the number of independent quadratic invariants is equal to J ⥠N â M* â„ N â M, where M* is the number of linearly independent rows in Thus, the problem of finding all independent quadratic invariants is reduced to a linear algebra problem in the Hamiltonian case. We establish that the properties of the quadratic invariants (e.g., locality) are related to the topological properties of the clusters (e.g., types of linkage). To do so, we formulate an algorithm for decomposing large clusters into smaller ones and show how various invariants are related to certain parts of a cluster, including the basic structures leading to M* < M. We illustrate our findings by presenting examples from the CharneyâHasegawaâMima wave model, and by showing a classification of small (up to three-triad) clusters
Criticality of Byproduct Materials: Assessing Supply Risk, Environmental Impact, and Strategic Policy Response for Tellurium
Creating a more sustainable future will require a transition toward more clean energy technologies. As technology shifts, the portfolio of materials needed to support the energy sector will shift as well. To prevent resource scarcity challenges, it is necessary to investigate multifaceted risks for energy materials. In recent years, a tool known as criticality assessment has been used for this purpose, identifying economic vulnerabilities for key energy, defense, and electronic technologies. These studies intend to guide strategic response to reduce risk; however existing methodologies lack a comprehensive systems perspective necessary to inform decisions.
This is particularly true for materials supplied from byproduct mining. Byproduct minerals (e.g. tellurium, indium, gallium) are unintended minor joint products generated while mining and refining major metals (e.g. aluminum, iron, copper). They contribute only marginally to profit, so their extraction is justified strictly by association with the carrier metal ore, linking their supply, both physically and economically, to the system of materials being produced by the joint process. This level of interconnection is not well captured by the single-product focus characteristic of existing criticality assessments, potentially misrepresenting risks for byproducts.
This dissertation aims to inform more appropriate policy response by addressing key gaps in criticality assessment and mitigation for byproduct minerals through the application of various systems modeling tools, including dynamic material flow analysis (dMFA), life cycle assessment (LCA), and scenario-based uncertainty analysis. Resulting contributions address the following specific challenges: (a) supply risk assessment neglects carrier metal production dynamics, (b) environmental risk assessment is sensitive to variability in impact allocation assumptions, and (c) standard, static result metrics are poorly matched for development of dynamic risk mitigation policy. Novel methodologies are demonstrated throughout using a case study of tellurium, a byproduct of copper refining critical to rapidly-growing CdTe thin-film photovoltaics
Identification of new transitional disk candidates in Lupus with Herschel
New data from the Herschel Space Observatory are broadening our understanding
of the physics and evolution of the outer regions of protoplanetary disks in
star forming regions. In particular they prove to be useful to identify
transitional disk candidates. The goals of this work are to complement the
detections of disks and the identification of transitional disk candidates in
the Lupus clouds with data from the Herschel Gould Belt Survey. We extracted
photometry at 70, 100, 160, 250, 350 and 500 m of all spectroscopically
confirmed Class II members previously identified in the Lupus regions and
analyzed their updated spectral energy distributions. We have detected 34 young
disks in Lupus in at least one Herschel band, from an initial sample of 123
known members in the observed fields. Using the criteria defined in Ribas et
al. (2013) we have identified five transitional disk candidates in the region.
Three of them are new to the literature. Their PACS-70 m fluxes are
systematically higher than those of normal T Tauri stars in the same
associations, as already found in T Cha and in the transitional disks in the
Chamaeleon molecular cloud. Herschel efficiently complements mid-infrared
surveys for identifying transitional disk candidates and confirms that these
objects seem to have substantially different outer disks than the T Tauri stars
in the same molecular clouds.Comment: Accepted for publication in A&A. 16 pages, 9 figures, 7 table
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In-sewer field-evaluation of an optical fibre-based condition monitoring system
A Fiber Bragg Grating (FBG) based monitoring system for continuous humidity and temperature measurement has been designed and evaluated experimentally in a sewer environment with high corrosion rates, humidity and the presence of gaseous hydrogen sulfide. The monitoring system has been designed specifically for field use, including packaging prepared for the harsh environment and the challenges of the operation. The system is battery powered and has hardware for controlling the interrogation equipment, power management, data logging and 4G connectivity. Results obtained show the long-term performance, over a 6-month period of non-stop monitoring of real-time data using the same probe. The data acquired was compared to the environmental data of temperature and precipitation for this period from the same location, which showed a good correlation between the expected and the measured data values. The data obtained point to the success of the optical fibre-based sensor system for monitoring in these harsh environments over long periods
Thermodynamics of a Colloidal Particle in a Time-Dependent Non-Harmonic Potential
We study the motion of an overdamped colloidal particle in a time-dependent
non-harmonic potential. We demonstrate the first law-like balance between
applied work, exchanged heat, and internal energy on the level of a single
trajectory. The observed distribution of applied work is distinctly
non-Gaussian in good agreement with numerical calculations. Both the Jarzynski
relation and a detailed fluctuation theorem are verified with good accuracy
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