Control Infrastructure for a Pulsed Ion Accelerator

We report on updates to the accelerator controls for the Neutralized Drift Compression Experiment II, a pulsed induction-type accelerator for heavy ions. The control infrastructure is built around a LabVIEW interface combined with an Apache Cassandra backend for data archiving. Recent upgrades added the storing and retrieving of device settings into the database, as well as ZeroMQ as a message broker that replaces LabVIEW's shared variables. Converting to ZeroMQ also allows easy access via other programming languages, such as Python

The reservoir network: A new network topology for district heating and cooling

Thermal district networks are effective solutions to substitute fossil fuels with renewable energy sources for heating and cooling. Moreover, thermal networking of buildings allows energy efficiency to be further increased. The waste heat from cooling can be reused for heating in thermal district systems. Because of bidirectional energy flows between prosumers, thermal networks require new hydraulic concepts. In this work, we present a novel network topology for simultaneous heating and cooling: the reservoir network. The reservoir network is robust in operation due to hydraulic decoupling of transfer stations, integrates heat sources and heat sinks at various temperature levels and is flexible in terms of network expansion. We used Modelica simulations to compare the new single-pipe reservoir network to a basecase double-pipe network, taking yearly demand profiles of different building types for heating and cooling. The electric energy consumed by the heat pumps and circulations pumps differs between the reservoir and base case networks by less than 1%. However, if the reservoir network is operated with constant instead of variable mass flow rate, the total electrical consumption can increase by 48% compared to the base case. As with any other network topology, the design and control of such networks is crucial to achieving energy efficient operation. Investment costs for piping and trenching depend on the district layout and dimensioning of the network. If a ring layout is applied in a district, the reservoir network with its single-pipe configuration is more economical than other topologies. For a linear layout, the piping costs are slightly higher for the reservoir network than for the base case because of larger pipe diameters

Self‐consistent scattering matrix calculation of the distribution function in semiconductor devices

The scattering matrix approach is a new technique for solving the Boltzmann equation in devices. We report a self-consistent application of the technique to realistic silicon devices exhibiting strong nonlocal effects. Simulation of a hot-electron, n-i-n diode demonstrates that the new technique efficiently and accurately reproduces Monte Carlo results without the statistical noise, allowing much tighter convergence with Poisson’s equation

Control System for the LEDA 6.7-MeV Proton Beam Halo Experiment

Measurement of high-power proton beam-halo formation is the ongoing scientific experiment for the Low Energy Demonstration Accelerator (LEDA) facility. To attain this measurement goal, a 52-magnet beam line containing several types of beam diagnostic instrumentation is being installed. The Experimental Physics and Industrial Control System (EPICS) and commercial software applications are presently being integrated to provide a real-time, synchronous data acquisition and control system. This system is comprised of magnet control, vacuum control, motor control, data acquisition, and data analysis. Unique requirements led to the development and integration of customized software and hardware. EPICS real-time databases, Interactive Data Language (IDL) programs, LabVIEW Virtual Instruments (VI), and State Notation Language (SNL) sequences are hosted on VXI, PC, and UNIX-based platforms which interact using the EPICS Channel Access (CA) communication protocol. Acquisition and control hardware technology ranges from DSP-based diagnostic instrumentation to the PLC-controlled vacuum system. This paper describes the control system hardware and software design, and implementation.Comment: LINAC2000 Conference, 4 pg

A Spectral Flux Method for Solving the Boltzmann Equation

A spectral method for solving the Boltzmann equation by the scattering matrix approach is presented, The algorithm discussed can be used to simulate both bulk and device properties with arbitrary field profiles. Although the primary goal is to reduce the data storage problem of the scattering matrix approach, many of the concepts and mathematical properties developed may be useful for other traditional spectral methods as well

FISH1D 2.1 User’s Manual

FISH1D is a computer program that solves the one-dimensional Poisson equation for electrostatic Fields In Semiconductor Heterostructures. The program will print or plot the electrostatic potential, electric field, electron and hole densities, dopant density, ionized dopant density, and other quantities of interest versus position at an applied bias voltage (assuming zero current). A capacitance or sheet carrier concentration versus voltage analysis may also be performed. While FISH1D was originally written for the ternary AlxGa1_xAs, it has been modified to simulate CdxHg1_xTe, ZnSe, GexSi1_x, and Si as well, and the program can be readily modified to analyze other semiconductors through the addition of new material subroutines or using the most recent option, the MATDEF card. This card enables the user to enter new material definitions by layers in the input deck without having to recompile, an advantage of FISH1D 2.1 over FISH1D 2.0. The primary purpose of this document is explain how to use FISH1D; for a more thorough discussion of the numerical implementation of FISH1D, the user is directed to the references. A theoretical basis for FISH1D is provided in Appendix I of this manual. The development of FISH1D was supported by the Semiconductor Research Corporation, the National Science Foundation Materials Research Laboratory, and by the Eastman Kodak Company

Grover Search for Portfolio Selection

We present explicit oracles designed to be used in Grover's algorithm to match investor preferences. Specifically, the oracles select portfolios with returns and standard deviations exceeding and falling below certain thresholds, respectively. One potential use case for the oracles is selecting portfolios with the best Sharpe ratios. We have implemented these algorithms using quantum simulators

Obese children sustain significantly more both bone forearm fractures when compared to non-obese children

The prevalence of obesity in children with ULBF was higher than in the general pediatric population. There was no statistical difference between both groups in the reported level of activity, in the kinetics and in the treatment modalities. Obese children had a significantly higher risk for a combined radius-ulna fracture. Further research is needed to evaluate the relationship between obesity, bone growth and trauma

The dehydration, rehydration and tectonic setting of greenstone belts in a portion of the northern Kaapvaal Craton, South Africa

High-grade gneiss terranes and low-grade granite-greenstone terranes are well known in several Archaean domains. The geological relationship between these different crustal regions, however, is still controversial. One school of thought favors fundamental genetic differences between high-grade and low-grade terranes while others argue for a depth-controlled crustal evolution. The detailed examination of well-exposed Archaean terranes at different metamorphic grades, therefore, is not only an important source of information about the crustal levels exposed, but also is critical to the understanding of the possible tectonic and metamorphic evolution of greenstone belts with time. Three South African greenstone belts are compared