Status of the Advanced Locomotive Propulsion System (ALPS) Project

The University of Texas at Austin Center for Electromechanics (UT-CEM) is currently developing an Advanced Locomotive Propulsion System (ALPS) as part of the Next Generation High Speed Rail program sponsored by the Federal Railroad Administration (FRA). Testing of the advanced propulsion system will be conducted as a portion of the FRA Non-Electric High Speed Locomotive Demonstration program. The project goal is to develop a non-electric locomotive propulsion system capable of 150 mph operation on existing infrastructure with good fuel economy and low noise and pollutant emissions. The propulsion system consists of two major elements: (1) a high speed generator directly coupled to a 5,000 hp gas turbine (turboalternator) to provide prime power and (2) an energy storage flywheel to provide additional power for acceleration and speed maintenance on grades, and to recover kinetic energy during braking. In addition to improving the overall system efficiency, the energy storage flywheel also provides load leveling for the turbine, reducing thermal cycling and significantly extending turbine maintenance intervals. The paper provides an overview of the ALPS system and presents the results of performance simulations to illustrate the benefits of the system. The paper also provides the current status of the project, along with component test results as available.Center for Electromechanic

Air-Core Compensated Pulsed Alternators

A compensated pulsed alternator is a generator capable of delivering high power energy pulses with current waveform flexibility. This versatile machine has applications in various fields where power density is at a premium. Recent advances in applying fiber/epoxy composites to rotating electrical machinery [l] have greatly enhanced the power density capabilities of this machine. A characteristic of these new machines is an absence of ferromagnetic material in the magnetic circuit, and they are therefore referred to as >air-core'' compulsators. This paper discusses the topological considerations and the capabilities of the family of machines called the air-core compulsators.Center for Electromechanic

Rotating Machine Development at The University of Texas

The Center for Electromechanics at The University of Texas at Austin (CEM-UT) is specialized in the development of high power, pulsed rotating machines for a variety of applications including fusion experiments, directed energy devices, and electrothermal and electromagnetic accelerators. For many of these applications, compulsators have emerged as viable power supplies. These machines are low impedance alternators which use flux compression to shape the discharge pulse and increase peak power and, to date, have been constructed from ferromagnetic materials. In the past several years, tremendous gains in energy and power densities have been predicted based on the use of composite materials. Glass, graphite, boron and Kevlar reinforced epoxy systems have the advantage of superior strength and stiffness, and are much lighter when compared to their metal counterparts. Two major efforts in which composite based (air-core) compulsators are being developed are now coming to fruition. Additionally, conceptual designs of several advanced concepts covering a wide range of pulse lengths and applications have been performed. The purpose of this paper is to report on the status of the machines currently being fabricated and describe the next generation of high performance compulsators.Center for Electromechanic

Rotordynamics Design and Test Results for a Model Scale Compulsator Rotor

The model scale compulsator is a high speed (12000 rpm), high energy rotating machine. The rotor is a highly optimized pulsed power electrical machine consisting of electrical windings, slip rings, and highly pre-stressed composite bandings. This paper describes the design of this machine from the standpoint of rotordynamics. The rotor is supported on oil-lubricated hybrid ceramic duplex ball bearings, which in turn are supported on compliant squeeze film dampers. Test results are presented for both mechanical checkout runs and full energy discharge experiments. Also described is experience gained from low speed balancing on a commercial balancing machine, followed by high speed in situ balancingCenter for Electromechanic

Compulsator Rotor Assembly Methods

High energy density requirements for fieldable electric gun applications have led to the development of air-core compulsators which utilize hybrid metal/composite rotor designs. In addition to supporting the required generator windings, these rotors also must store large amounts of kinetic energy. To satisfy energy density requirements, the tip speeds of the electric gun class compulsator rotor are appreciable with typical values exceeding 500 m/s for near term designs. High performance composites are utilized in the rotor structures and large amounts of radial pre-load is required to hold the rotor structure and electrical windings together at the tip speeds required.Center for Electromechanic

Operating Modes for Compulsator Based Electromagnetic Launcher Systems

The compensated pulsed alternator (compulsator) is a versatile power supply capable of interfacing with the electromagnetic launcher in various ways. The method that has been explored at length with several systems is the single phase option. Several variants of this option, some using advanced pulse shaping techniques, have been discussed in prior publications [I-3]. Besides this basic single pulse method of operating there are several other methods each with its pros and cons. The multi-phase option is discussed in this paper. Within the broad class of multi-phase systems there are further sub-classes, namely alternating current drive and unidirectional current drives. Thus the branching of these operating modes gives rise to a variety of operating modes. Each one of these operating modes is described and simulation results are presented.Center for Electromechanic

Effect of dissipation and measurement on a tunneling system

We consider a parametrically driven Kerr medium in which the pumping may be sinusoidally varied. It has been previously found that this system exhibits coherent tunneling between two fixed points which can be either enhanced or suppressed by altering the driving frequency and strength. We numerically investigate the dynamics when damping is included. This is done both by solving a master equation and using the quantum-trajectory method. In the latter case it is also possible to model the result of a continuous heterodyne measurement of the cavity output. The dissipation destroys the coherences which give rise to the tunneling, causing the sinusoidal oscillation of the mean to give way to a stochastic jumping between the fixed points, manifested as a random telegraph signal. In the quantum-trajectory picture we show that the coherences responsible for tunneling are an exponentially decreasing function of the signal-to-noise ratio for heterodyne measurements. However, evidence of both the bare tunneling rate and the driving modified tunneling rate are still apparent in the random telegraph signal

Measurement of the View the tt production cross-section using eμ events with b-tagged jets in pp collisions at √s = 13 TeV with the ATLAS detector

This paper describes a measurement of the inclusive top quark pair production cross-section (σtt¯) with a data sample of 3.2 fb−1 of proton–proton collisions at a centre-of-mass energy of √s = 13 TeV, collected in 2015 by the ATLAS detector at the LHC. This measurement uses events with an opposite-charge electron–muon pair in the final state. Jets containing b-quarks are tagged using an algorithm based on track impact parameters and reconstructed secondary vertices. The numbers of events with exactly one and exactly two b-tagged jets are counted and used to determine simultaneously σtt¯ and the efficiency to reconstruct and b-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section is measured to be: σtt¯ = 818 ± 8 (stat) ± 27 (syst) ± 19 (lumi) ± 12 (beam) pb, where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, the integrated luminosity and the LHC beam energy, giving a total relative uncertainty of 4.4%. The result is consistent with theoretical QCD calculations at next-to-next-to-leading order. A fiducial measurement corresponding to the experimental acceptance of the leptons is also presented

Search for strong gravity in multijet final states produced in pp collisions at √s=13 TeV using the ATLAS detector at the LHC

A search is conducted for new physics in multijet final states using 3.6 inverse femtobarns of data from proton-proton collisions at √s = 13TeV taken at the CERN Large Hadron Collider with the ATLAS detector. Events are selected containing at least three jets with scalar sum of jet transverse momenta (HT) greater than 1TeV. No excess is seen at large HT and limits are presented on new physics: models which produce final states containing at least three jets and having cross sections larger than 1.6 fb with HT > 5.8 TeV are excluded. Limits are also given in terms of new physics models of strong gravity that hypothesize additional space-time dimensions

Search for TeV-scale gravity signatures in high-mass final states with leptons and jets with the ATLAS detector at sqrt [ s ] = 13TeV

A search for physics beyond the Standard Model, in final states with at least one high transverse momentum charged lepton (electron or muon) and two additional high transverse momentum leptons or jets, is performed using 3.2 fb−1 of proton–proton collision data recorded by the ATLAS detector at the Large Hadron Collider in 2015 at √s = 13 TeV. The upper end of the distribution of the scalar sum of the transverse momenta of leptons and jets is sensitive to the production of high-mass objects. No excess of events beyond Standard Model predictions is observed. Exclusion limits are set for models of microscopic black holes with two to six extra dimensions