Rural Facility Electric Power Quality Enhancement

Electric power disturbances are known to be more prevalent in small, isolated power systems than in larger interconnected grids which service most of the United States. This fact has given rise to a growing concern about the relative merits of different types of power conditioning equipment and their effectiveness in protecting sensitive electronics and essential loads in rural Alaska. A study has been conducted which compares isolation transformers, voltage regulators, power conditioners, uninterruptible power supplies and indoor computer surge suppressors in their ability to suppress the various disturbances which have been measured in several Alaskan communities. These include voltage sags and surges, impulses, blackouts, frequency variations and long-term voltage abnormalities. In addition, the devices were also subjected to fast, high-magnitude impulses such as might be expected in the event of a lightning strike to or near utility distribution equipment. The solutions for power line problems will vary for different load applications and for different rural electrical environments. The information presented in this report should prove to be valuable in making the analysis.List of Figures - viii List of Tables - xiv Acknowledgements - xv Chapter 1: Electric Disturbances in Power Systems Introduction - 16 Categorizing Electrical Disturbances - 17 Voltage Disturbances and Transients - 19 Frequency Disturbances - 22 Sources of Transients - 22 Lightning and EMP - 23 Switching - 24 Power System Noise - 25 Common Mode and Normal Mode Noise Signals - 26 Chapter 2: Power Quality in Rural Alaska Characterizing the Village Power System - 28 The Village Electric Load - 29 Power Quality Site Surveys - 30 Rural Power Quality in Alaska - 31 Power Conditioning Requirements for Village Loads - 37 Chapter 3: Isolation, Voltage Regulation and Power Conditioning Introduction - 39 Slow Voltage Fluctuations - 39 Voltage Regulation and Power Conditioning - 40 Ferroresonant Transformers - 40 Electronic Tap-Changing Regulators - 44 Isolation Transformers - 47 Dedicated Lines - 51 Chapter 4: Impulse Suppression Introduction - 52 Surge Suppressors - 52 Surge Suppressor Components - 55 Component Configuration - 58 EMI/RFI Filters - 58 Standard Tests for Evaluating Surge Suppressor Performance - 60 Scope of Impulse Testing for Rural Alaska - 60 Impulse Test Equipment - 62 Test Procedure - 62 Impulse Testing Measurements - 63 Test Results - 64 Chapter 5: Uninterruptible Power Supplies The True UPS - 68 Standby Power Systems and a New Generation of UPS - 69 UPS Backup Time - 74 UPS Testing - 74 Chapter 6: Computers and Power Problems Introduction - 78 The Computer Tolerance Envelope - 78 Ridethrough - 80 Component Degradation and Equipment Failure - 82 Computer Power Supplies - 82 Linear Power Supplies - 83 Switching Power Supplies - 84 PC Tolerance of Powerline Disturbances - 84 Chapter 7: Comparing Power Conditioning Alternatives Voltage Regulation - 89 Isolation - 93 Uninterruptible Power Systems - 94 Computer Surge Suppressors - 98 Summary - 98 Appendices Appendix A: Voltage Clamping Levels of Surge Suppressors - 101 Appendix B: Voltage Clamping Levels of Power Conditioners and Uninterruptible Power Systems - 115 Appendix C: Noise Suppression of Surge Suppressors and Power Conditioners - 129 Appendix D: Waveforms and Regulating Characteristics of Power Conditioners and Uninterruptible Power Systems - 135 Appendix E: Comparison of Voltage Clamping Levels of Surge Suppressors Power Conditioners, Isolation Transformers and Uninterruptible Power Systems to High-Magnitude Impulse Voltages - 151 References - 16

Self-consistent description of nuclear compressional modes

Isoscalar monopole and dipole compressional modes are computed for a variety of closed-shell nuclei in a relativistic random-phase approximation to three different parametrizations of the Walecka model with scalar self-interactions. Particular emphasis is placed on the role of self-consistency which by itself, and with little else, guarantees the decoupling of the spurious isoscalar-dipole strength from the physical response and the conservation of the vector current. A powerful new relation is introduced to quantify the violation of the vector current in terms of various ground-state form-factors. For the isoscalar-dipole mode two distinct regions are clearly identified: (i) a high-energy component that is sensitive to the size of the nucleus and scales with the compressibility of the model and (ii) a low-energy component that is insensitivity to the nuclear compressibility. A fairly good description of both compressional modes is obtained by using a ``soft'' parametrization having a compression modulus of K=224 MeV.Comment: 28 pages and 10 figures; submitted to PR

Low-Energy Universality in Atomic and Nuclear Physics

An effective field theory developed for systems interacting through short-range interactions can be applied to systems of cold atoms with a large scattering length and to nucleons at low energies. It is therefore the ideal tool to analyze the universal properties associated with the Efimov effect in three- and four-body systems. In this "progress report", we will discuss recent results obtained within this framework and report on progress regarding the inclusion of higher order corrections associated with the finite range of the underlying interaction.Comment: Commissioned article for Few-Body Systems, 47 pp, 16 fig

Dissociative covalent adaptable networks from unsaturated polyesters

Unsaturated polyesters (UPEs) are a class of thermosetting resins which are prevalent in the polymer industry, offering excellent durability in many applications. However, their permanent crosslinks prevent re-use or recycling at their end-of-life. This problem is addressed using UPEs to generate dissociative covalent adaptable networks (CANs). Poly(propylene maleate) and poly(propylene fumarate) were copolymerised with furan-functionalised crosslinkers to form networks comprising reversible Diels-Alder cycloadducts. The thermal properties of each material were analysed by differential scanning calorimetry (DSC), showing that the furan-maleate networks dissociated at 130 °C compared to the furan-fumarate networks which dissociated at a significantly lower temperature (100 °C). The network formed from poly(propylene maleate) using a flexible trifunctional furan crosslinker provided the largest increase in T g and T rDA, producing the highest gel fraction (99 %) and a stable plateau modulus of 10 MPa by DMA. The networks reform at ambient temperature, although the rate of formation can be increased significantly by mild heating at 65 °C. Overall, the results indicate that furan-maleate CANs behave like reference furan-maleimide networks. Thermal analysis indicated that the furan-maleate cycloadduct was retained by heating to 150 °C, whereas isomerisation of maleate to fumarate was observed after repeated heating cycles to 180 °C. Mechanical testing showed that a bond strength of almost 10 MPa was achieved using these CANs as adhesives, which could be readily modified through changes in copolymer composition

Cellular uptake and retention of nanoparticles: Insights on particle properties and interaction with cellular components

The utilization of nanomaterials in the biological and medical field is quickly progressing, particularly in areas where traditional diagnostics and treatment approaches have limited success. The success of nanomaterials in medical products such as biomedical implants, wound dressings and drug delivery systems rely upon their effective interaction between the extracellular matrix, cells, and intracellular components. Upon contact with mammalian cells, nanoparticles (NPs) begin to interact with the extracellular matrix, cell membrane, cytoplasmic proteins, nucleus, and other cellular organelles, which result in nanoparticle internalization and subsequent cellular responses. Such responses elicited by the mammalian cells as a result of the cell-nanomaterials interactions, both at the cellular and molecular level, are mainly determined by the morphological, chemical, and surface characteristics of the nanomaterials themselves. This review provides an overview of how such different attributes, such as chemical nature, size, shape, surface charge, topography, stiffness, and functional features of nanomaterials, influence the cell-nanomaterials interactions.Scopu

Short note on improved integration of mechanical testing in predictive wear models

In this work, a new global increment nano-fretting wear model based on the effective indenter concept has been used and the results were compared with experimental data. A series of DLC coatings with varied mechanical properties was deposited using industrial scale PECVD system and characterised on a low-drift nanomechanical test platform (NanoTest Vantage). 4500. cycle nano-scale fretting measurements have been performed in order to examine the tribological properties of the coatings. A physical analysis of the nanoindentation test enabled the true coating Young's Modulus (E) and the coating yield strength (Y) to be determined. In comparison to the hardness (H) this is the basis for a more generic understanding of the mechanical coating behaviour. This allowed a direct examination of the influence of the variation of Y/. E in the coatings on the observed nano-fretting wear, with the coating with highest Y/. E showing significantly improved resistance to nano-fretting wear. A preliminary evaluation of the stress field evolution during the test and the extraction of wear and fretting parameters provides the opportunity to discuss the effects possibly being dominant within the nano-scale tribo-tests

Monte-Carlo Simulations of Radiation-Induced Activation in a Fast-Neutron and Gamma- Based Cargo Inspection System

An air cargo inspection system combining two nuclear reaction based techniques, namely Fast-Neutron Resonance Radiography and Dual-Discrete-Energy Gamma Radiography is currently being developed. This system is expected to allow detection of standard and improvised explosives as well as special nuclear materials. An important aspect for the applicability of nuclear techniques in an airport inspection facility is the inventory and lifetimes of radioactive isotopes produced by the neutron and gamma radiation inside the cargo, as well as the dose delivered by these isotopes to people in contact with the cargo during and following the interrogation procedure. Using MCNPX and CINDER90 we have calculated the activation levels for several typical inspection scenarios. One example is the activation of various metal samples embedded in a cotton-filled container. To validate the simulation results, a benchmark experiment was performed, in which metal samples were activated by fast-neutrons in a water-filled glass jar. The induced activity was determined by analyzing the gamma spectra. Based on the calculated radioactive inventory in the container, the dose levels due to the induced gamma radiation were calculated at several distances from the container and in relevant time windows after the irradiation, in order to evaluate the radiation exposure of the cargo handling staff, air crew and passengers during flight. The possibility of remanent long-lived radioactive inventory after cargo is delivered to the client is also of concern and was evaluated.Comment: Proceedings of FNDA 201

BOUT++: a framework for parallel plasma fluid simulations

A new modular code called BOUT++ is presented, which simulates 3D fluid equations in curvilinear coordinates. Although aimed at simulating Edge Localised Modes (ELMs) in tokamak X-point geometry, the code is able to simulate a wide range of fluid models (magnetised and unmagnetised) involving an arbitrary number of scalar and vector fields, in a wide range of geometries. Time evolution is fully implicit, and 3rd-order WENO schemes are implemented. Benchmarks are presented for linear and non-linear problems (the Orszag-Tang vortex) showing good agreement. Performance of the code is tested by scaling with problem size and processor number, showing efficient scaling to thousands of processors. Linear initial-value simulations of ELMs using reduced ideal MHD are presented, and the results compared to the ELITE linear MHD eigenvalue code. The resulting mode-structures and growth-rate are found to be in good agreement (BOUT++ = 0.245, ELITE = 0.239). To our knowledge, this is the first time dissipationless, initial-value simulations of ELMs have been successfully demonstrated.Comment: Submitted to Computer Physics Communications. Revised to reduce page count. 18 pages, 16 figure

Non-linear regression models for Approximate Bayesian Computation

Approximate Bayesian inference on the basis of summary statistics is well-suited to complex problems for which the likelihood is either mathematically or computationally intractable. However the methods that use rejection suffer from the curse of dimensionality when the number of summary statistics is increased. Here we propose a machine-learning approach to the estimation of the posterior density by introducing two innovations. The new method fits a nonlinear conditional heteroscedastic regression of the parameter on the summary statistics, and then adaptively improves estimation using importance sampling. The new algorithm is compared to the state-of-the-art approximate Bayesian methods, and achieves considerable reduction of the computational burden in two examples of inference in statistical genetics and in a queueing model.Comment: 4 figures; version 3 minor changes; to appear in Statistics and Computin

Cranked Relativistic Hartree-Bogoliubov Theory: Superdeformed Bands in the A∼190A\sim 190 Region

Cranked Relativistic Hartree-Bogoliubov (CRHB) theory is presented as an extension of Relativistic Mean Field theory with pairing correlations to the rotating frame. Pairing correlations are taken into account by a finite range two-body force of Gogny type and approximate particle number projection is performed by Lipkin-Nogami method. This theory is applied to the description of yrast superdeformed rotational bands observed in even-even nuclei of the $A\sim 190$ mass region. Using the well established parameter sets NL1 for the Lagrangian and D1S for the pairing force one obtains a very successful description of data such as kinematic ($J^{(1)}$) and dynamic ($J^{(2)}$) moments of inertia without any adjustment of new parameters. Within the present experimental accuracy the calculated transition quadrupole moments $Q_t$ agree reasonably well with the observed data.Comment: 6 pages including 4 PostScript figures, uses RevTex, revised version, Phys.Rev. C, Rapid Communications, in pres