2,733 research outputs found

    Windowed Green Function Method for Nonuniform Open-Waveguide Problems

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    This contribution presents a novel Windowed Green Function (WGF) method for the solution of problems of wave propagation, scattering and radiation for structures which include open (dielectric) waveguides, waveguide junctions, as well as launching and/or termination sites and other nonuniformities. Based on use of a "slow-rise" smooth-windowing technique in conjunction with free-space Green functions and associated integral representations, the proposed approach produces numerical solutions with errors that decrease faster than any negative power of the window size. The proposed methodology bypasses some of the most significant challenges associated with waveguide simulation. In particular the WGF approach handles spatially-infinite dielectric waveguide structures without recourse to absorbing boundary conditions, it facilitates proper treatment of complex geometries, and it seamlessly incorporates the open-waveguide character and associated radiation conditions inherent in the problem under consideration. The overall WGF approach is demonstrated in this paper by means of a variety of numerical results for two-dimensional open-waveguide termination, launching and junction problems.Comment: 16 Page

    Natural Gauge and Gravitational Coupling Unification and the Superpartner Masses

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    The possibility to achieve unification at the string scale in the context of the simplest supersymmetric grand unified theory is investigated. We find conservative upper bounds on the superpartner masses consistent with the unification of gauge and gravitational couplings, M_{\tilde G} < 5 TeV and M_{\tilde f} < 3 \times 10^7 GeV, for the superparticles with spin one-half and zero, respectively. These bounds hint towards the possibility that this supersymmetric scenario could be tested at future colliders, and in particular, at the forthcoming LHC.Comment: 8 pages, 4 figures, version accepted in Physics Letters

    3D Mapping of indoor environments using RGB-D Kinect camera for robotic mobile application

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    RGB-D cameras are new, low cost, sensors that provide depth information for every RGB pixel acquired. Combining this information, it is possible to develop 3D perception in an indoor environment. In this paper we investigate how this technology can be used for building 3D maps. Such maps can gain more importance in the context of mobile robotics, as it can be used for many applications such as robot navigation. We present how, knowing the robot's pose, it is possible to build such maps and extract useful information like recognize objects and determine their position within the map.Outgoin

    Unimolecular Dissociation Of Peroxyformic Acid Initiated By Vibrational Overtone Excitation To The 6&#957;oh State

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    Photodissociation is an important loss mechanism for atmospheric hydroperoxides (R-O-OH) leading to the production of OH radicals via the rupture of the weak O-O bond. Photodissociation can either occur through electronic excitation to a repulsive excited electronic state or, alternatively, through unimolecular dissociation on the ground electronic surface. Here we present results from the unimolecular dissociation of peroxyformic acid (PFA) initiated by exciting the molecule in the vicinity of its fifth OH stretching overtone state (6ν\nuOH) at both 615 and 626nm. Based on the estimated heat of formation of PFA and its fragments, the O-O bond dissociation energy (D0_{0}) in PFA is estimated to be ~45.1 kcal/mol. Thus, exciting room temperature PFA molecules at 615 nm and 626 nm is expected to leave the OH + HCO2_{2} fragments with roughly 3.3 kcal/mol and 2.5 kcal/mol of available energy, respectively. Using laser induced fluorescence (LIF), we have probed the OH fragments from the near threshold unimolecular dissociation and have determined the partitioning of the available energy in to its internal and translational degrees of freedom. These results, along with the insight they provide regarding the unimolecular dissociation dynamics of HC(O)OOH, will be presented

    Exploring requirements and detector solutions for FCC-ee

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    Circular colliders have the advantage of delivering collisions to multiple interaction points, which allow different detector designs to be studied and optimized - up to four for FCC-ee. On the one hand, the detectors must satisfy the constraints imposed by the invasive interaction region layout. On the other hand, the performance of heavy-flavour tagging, of particle identification, of tracking and particle-flow reconstruction, and of lepton, jet, missing energy and angular resolution, need to match the physics programme and the exquisite statistical precision offered by FCC-ee. During the FCC feasibility study (2021-2025), benchmark physics processes will be used to determine, via appropriate simulations, the requirements on the detector performance or design that must be satisfied to ensure that the systematic uncertainties of the measurements are commensurate with their statistical precision. The usage of the data themselves, in order to reach the challenging goals on the stability and on the alignment of the detector, in particular for the programme at and around the Z peak, will also be studied. In addition, the potential for discovering very weakly coupled new particles, in decays of Z or Higgs bosons, could motivate dedicated detector designs that would increase the efficiency for reconstructing the unusual signatures of such processes. These studies are a crucial input to the further optimization of the two concepts described in the Conceptual Design Report, CLD, and IDEA, and to the development of new concepts which might actually prove to be better adapted to the FCC-ee physics programme, or parts thereof.Comment: Submitted to EPJ+ special issue: A future Higgs and Electroweak factory (FCC): Challenges towards discovery, Focus on FCC-e

    Wildfires & Drought Analysis for the Capital Area Council of Governments

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    Capital Area Council of Governments 2002-2012 Student: Emmanuel Rubio Perez Professor: Dr. James PhelpsAn analysis of available national data on droughts and wildfires indicate that Texas has encompassed a fluctuating drought for over a decade. The central and western portions of the state have been affected particularly severely. In 2011 for example, the Capital Area Council of Governments (CAPCOG) endured drastic drought and wildfire conditions. Counties such as Bastrop, made major news headlines as the Bastrop County Complex Fire consumed more than 30,000 acres. Not all the local and rural governmental authorities may have the necessary data or technology to analyze the challenging threats posed by drought or to effectively plan for the wildfire threats that have slowly developed to become part of the CAPGOC community. Therefore, the purpose of research is to muster the data of the enduring wildfire and drought conditions over the decade spanning 2002 to 2012 across the CAPCOG. This project formulated visual data of the historical archived conditions for the fire services, emergency managers, and community leaders within the CAPCOG jurisdiction in order to help enhance their mitigation efforts in relation to future drought and wildfire events

    A Review of Wildfires and Drought Conditions for the Capital Area Council of Governments: 2002 to 2012

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    An analysis of available national data on droughts and wildfires indicate that Texas has encompassed a fluctuating drought for over a decade. The central and western portions of the state have been affected particularly severely. In 2011 for example, the Capital Area Council of Governments (CAPCOG) endured drastic drought and wildfire conditions. Counties such as Bastrop, made major news headlines as the Bastrop County Complex Fire consumed more than 30,000 acres. While the use of technology to track and manage wildfire threat has increased in recent years, a project I just completed in BOR 6302, Introduction to GIS, found that many smaller county and city fire services are lacking the historical digital data that could be used to prepare for future wildfires, mitigate the damage caused, and expedite recovery operations. Therefore, the purpose of research is to muster the data of the enduring wildfire and drought conditions over the decade spanning 2002 to 2012 across the CAPCOG. The research of acquired data incorporated within the archives kept by various organizations to include the Texas A&M Forest Service, Water Data for Texas Organization, Southern Regional Climate Center, Water Development Board, and the United States Drought Monitor. This project produced a visual data set of the historical drought and wildfire conditions for the fire services, emergency managers, and community leaders within that jurisdiction in order to help enhance their planning efforts for future events

    Modelling and Control of the Moisture in a Test Bench Flow with Time-delay

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    International audienceMoisture control in systems with time delay is studied in this work to be assessed in a process-control system (Test bench). To further investigate the phenomenon of transport delay in flows, the test bench system has been studied. In this work it is presented the design and validation of a model which describes the dynamics of mass transport phenomena. In order to control the moisture in the test bench, it is design a state-feedback controller such that the closed-loop system is robustly stable has an upper bound for the time delay
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