Design and Performance Analysis of a Non-Standard EPICS Fast Controller

The large scientific projects present new technological challenges, such as the distributed control over a communication network. In particular, the middleware EPICS is the most extended communication standard in particle accelerators. The integration of modern control architectures in these EPICS networks is becoming common, as for example for the PXI/PXIe and xTCA hardware alternatives. In this work, a different integration procedure for PXIe real time controllers from National Instruments is proposed, using LabVIEW as the design tool. This methodology is considered and its performance is analyzed by means of a set of laboratory experiments. This control architecture is proposed for achieving the implementation requirements of the fast controllers, which need an important amount of computational power and signal processing capability, with a tight real-time demand. The present work studies the advantages and drawbacks of this methodology and presents its comprehensive evaluation by means of a laboratory test bench, designed for the application of systematic tests. These tests compare the proposed fast controller performance with a similar system implemented using an standard EPICS IOC provided by the CODAC system.Comment: This is the extended version of the Conference Record presented in the IEEE Real-Time Conference 2014, Nara, Japan. This paper has been submitted to the IEEE Transactions on Nuclear Scienc

Expanding Rapid Prototyping for Electronic Systems Integration of Arbitrary Form

An innovative method for rapid prototyping (RP) of electronic circuits with components characteristic of typical electronics applications was demonstrated using an enhanced version of a previously developed hybrid stereolithography (SL) and direct write (DW) system, where an existing SL machine was integrated with a three-axis DW fluid dispensing system for combined arbitrary form electronic systems manufacturing. This paper presents initial efforts at embedding functional electronic circuits using the hybrid SL/DW system. A simple temperature-sensitive circuit was selected, which oscillated an LED at a frequency proportional to the temperature sensed by the thermistor. The circuit was designed to incorporate all the required electronic components within a 2.5” x 2” x 0.5” SL part. Electrical interconnects between electronic components were deposited on the SL part with a DW system using silver conductive ink lines. Several inks were deposited, cured, and tested on a variety of SL resin substrates, and the E 1660 ink (Ercon Inc, Wareham, MA) was selected due to its measured lowest average resistivity on the SL substrates. The finished circuit was compared with Printed Circuit Board (PCB) technology for functionality. The electronic components used here include a low voltage battery, LM 555 timer chip, resistors, a thermistor, capacitors, and Light Emitting Diodes (LEDs). This circuit was selected because it (1) represented a simple circuit combining many typically used electronic components and thus provided a useful demonstration for integrated electronic systems manufacturing applicable to a wide variety of devices, and (2) provided an indication of the parasitic resistances and capacitances introduced by the fabrication process due to its sensitivity to manufacturing variation. The hybrid technology can help achieve significant size reductions, enable systems integration in atypical forms, a natural resistance to reverse engineering and possibly increase maximum operating temperatures of electronic circuits as compared to the traditional PCB process. This research demonstrates the ability of the hybrid SL/DW technology for fabricating combined electronic systems for unique electronics applications in which arbitrary form is a requirement and traditional PCB technology cannot be used.Mechanical Engineerin

MatSWMM - An open-source toolbox for designing real-time control of urban drainage systems

This manuscript describes the MatSWMM toolbox, an open-source Matlab, Python, and LabVIEW-based software package for the analysis and design of real-time control (RTC) strategies in urban drainage systems (UDS). MatSWMM includes control-oriented models of UDS, and the storm water management model (SWMM) of the US Environmental Protection Agency (EPA), as well as systematic-system edition functionalities. Furthermore, MatSWMM is also provided with a population-dynamics-based controller for UDS with three of the fundamental dynamics, i.e., the Smith, projection, and replicator dynamics. The simulation algorithm, and a detailed description of the features of MatSWMM are presented in this manuscript in order to illustrate the capabilities that the tool has for educational and research purposes.Peer ReviewedPostprint (author's final draft

A Web-Based Distributed Virtual Educational Laboratory

Evolution and cost of measurement equipment, continuous training, and distance learning make it difficult to provide a complete set of updated workbenches to every student. For a preliminary familiarization and experimentation with instrumentation and measurement procedures, the use of virtual equipment is often considered more than sufficient from the didactic point of view, while the hands-on approach with real instrumentation and measurement systems still remains necessary to complete and refine the student's practical expertise. Creation and distribution of workbenches in networked computer laboratories therefore becomes attractive and convenient. This paper describes specification and design of a geographically distributed system based on commercially standard components

Developing vanadium redox flow technology on a 9-kW 26-kWh industrial scale test facility: Design review and early experiments

Redox Flow Batteries (RFBs) have a strong potential for future stationary storage, in view of the rapid expansion of renewable energy sources and smart grids. Their development and future success largely depend on the research on new materials, namely electrolytic solutions, membranes and electrodes, which is typically conduced on small single cells. A vast literature on these topics already exists. However, also the technological development plays a fundamental role in view of the successful application of RFBs in large plants. Despite that, very little research is reported in literature on the technology of large RFB systems. This paper presents the design, construction and early operation of a vanadium redox flow battery test facility of industrial size, dubbed IS-VRFB, where such technologies are developed and tested. In early experiments a peak power of 8.9 kW has been achieved with a stack specific power of 77Wkg−1. The maximum tested current density of 635 mA cm−2 has been reached with a cell voltage of 0.5 V, indicating that higher values can be obtained. The test facility is ready to be complemented with advanced diagnostic devices, including multichannel electrochemical impedance spectroscopy for studying aging and discrepancies in the cell behaviors

Measurements of greenhouse gases and related tracers at Bialystok tall tower station in Poland

Quasi-continuous, in-situ measurements of atmospheric CO2, O2/N2, CH4, CO, N2O, and SF6 have been performed since August 2005 at the tall tower station near Bialystok, in Eastern Poland, from five heights up to 300 m. Besides the in-situ measurements, flask samples are filled approximately weekly and measured at Max-Planck Institute for Biogeochemistry for the same species and, in addition, for H2, Ar/N2 and the stable isotopes 13C and 18O in CO2. The in-situ measurement system was built based on commercially available analysers: a LiCor 7000 for CO2, a Sable Systems "Oxzilla" FC-2 for O2, and an Agilent 6890 gas chromatograph for CH4, CO, N2O and SF6. The system was optimized to run continuously with very little maintenance and to fulfill the precision requirements of the CHIOTTO project. The O2/N2 measurements in particular required special attention in terms of technical setup and quality assurance. The evaluation of the performance after more than three years of operation gave overall satisfactory results, proving that this setup is suitable for long term remote operation with little maintenance. The precision achieved for all species is within or close to the project requirements. The comparison between the in-situ and flask sample results, used to verify the accuracy of the in-situ measurements, showed no significant difference for CO2, O2/N2, CH4 and N2O, and a very small difference for SF6. The same comparison however revealed a statistically significant difference for CO, of about 6.5 ppb, for which the cause could not be fully explained. From more than three years of data, the main features at Bialystok have been characterized in terms of variability, trends, and seasonal and diurnal variations. CO2 and O2/N2 show large short term variability, and large diurnal signals during the warm seasons, which attenuate with the increase of sampling height. The trends calculated from this dataset, over the period August 2005 to December 2008, are 2.02±0.46 ppm/year for CO2 and -23.2±2.5 per meg/year for O2/N2. CH4, CO and N2O show also higher variability at the lower sampling levels, which in the case of CO is strongly seasonal. Diurnal variations in CH4, CO and N2O mole fractions can be observed during the warm season, due to the periodicity of vertical mixing combined with the diurnal cycle of anthropogenic emissions. We calculated increase rates of 10.1±4.4 ppb/year for CH4, (-8.3)±5.3 ppb/year for CO and 0.67±0.08 ppb/year for N2O. SF6 shows only few events, and generally no vertical gradients, which suggests that there are no significant local sources. A weak SF6 seasonal cycle has been detected, which most probably is due to the seasonality of atmospheric circulation. SF6 increased during the time of our measurement at an average rate of 0.29±0.01 ppt/year

Partial discharge behavior under operational and anomalous conditions in HVDC systems

Power cables undergo various types of overstressing conditions during their operation that influence the integrity of their insulation systems. This causes accelerated ageing and might lead to their premature failure in severe cases. This paper presents an investigation of the impacts of various dynamic electric fields produced by ripples, polarity reversal and transient switching impulses on partial discharge (PD) activity within solid dielectrics with the aim of considering such phenomena in high voltage direct current (HVDC) cable systems. Appropriate terminal voltages of a generic HVDC converter were reproduced - with different harmonic contaminations - and applied to the test samples. The effects of systematic operational polarity reversal and superimposed switching impulses with the possibility of transient polarity reversal were also studied in this investigation. The experimental results show that the PD is greatly affected by the dynamic changes of electric field represented by polarity reversal, ripples and switching. The findings of this study will assist in understanding the behaviour of PDs under HVDC conditions and would be of interest to asset managers considering the effects of such conditions on the insulation diagnostics

Implementation and performance of SIBYLS: a dual endstation small-angle X-ray scattering and macromolecular crystallography beamline at the Advanced Light Source.

The SIBYLS beamline (12.3.1) of the Advanced Light Source at Lawrence Berkeley National Laboratory, supported by the US Department of Energy and the National Institutes of Health, is optimized for both small-angle X-ray scattering (SAXS) and macromolecular crystallography (MX), making it unique among the world's mostly SAXS or MX dedicated beamlines. Since SIBYLS was commissioned, assessments of the limitations and advantages of a combined SAXS and MX beamline have suggested new strategies for integration and optimal data collection methods and have led to additional hardware and software enhancements. Features described include a dual mode monochromator [containing both Si(111) crystals and Mo/B(4)C multilayer elements], rapid beamline optics conversion between SAXS and MX modes, active beam stabilization, sample-loading robotics, and mail-in and remote data collection. These features allow users to gain valuable insights from both dynamic solution scattering and high-resolution atomic diffraction experiments performed at a single synchrotron beamline. Key practical issues considered for data collection and analysis include radiation damage, structural ensembles, alternative conformers and flexibility. SIBYLS develops and applies efficient combined MX and SAXS methods that deliver high-impact results by providing robust cost-effective routes to connect structures to biology and by performing experiments that aid beamline designs for next generation light sources

Methodology and calibration for continuous measurements of biogeochemical trace gas and O2 concentrations from a 300-m tall tower in central Siberia

We present an integrated system for measuring atmospheric concentrations of CO2, O2, CH4, CO, and N2O in central Siberia. Our project aims to demonstrate the feasibility of establishing long-term, continuous, high precision atmospheric measurements to elucidate greenhouse gas processes from a very remote, mid-continental boreal environment. Air is sampled from five heights on a custom-built 300-m tower. Common features to all species' measurements include air intakes, an air drying system, flushing procedures, and data processing methods. Calibration standards are shared among all five measured species by extending and optimising a proven methodology for long-term O2 calibration. Our system achieves the precision and accuracy requirements specified by the European Union's "CarboEurope" and "ICOS" (Integrated Carbon Observing System) programmes in the case of CO2, O2, and CH4, while CO and N2O require some further improvements. It was found that it is not possible to achieve these high precision measurements without skilled technical assistance on-site, primarily because of 2–3 month delays in access to data and diagnostic information. We present results on the stability of reference standards in high pressure cylinders. It was also found that some previous methods do not mitigate fractionation of O2 in a sample airstream to a satisfactory level