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Short-term household electricity load forecasting is important for utility companies to ensure reliable power supplies. Traditional methods for load forecasting relied on historical records from one single data source and have limitations with insufficient or missing data. Recently, an emerging family of machine learning algorithms, multitask learning (MTL), has been developed and has the potential for load forecasting. By MTL, the electricity consumption data from multiple communities can be fused to improve forecasting accuracy. However, appropriate modeling of the relatedness to enable the between-community knowledge transfer remains a challenge. This paper proposes an improved MTL algorithm for a Bayesian spatiotemporal Gaussian process model (BSGP) to characterize the relatedness among the different residential communities. It hypothesizes on the similar impacts of environmental and traffic conditions on electricity consumption in improving short-term load forecasting. Furthermore, this paper proposes a low-ranked dirty model along with an iterative algorithm to improve the learning of model parameters under an MTL framework. This paper uses a real-world case study from two residential communities in Tallahassee, Fl, USA, to demonstrate the method effectiveness. The proposed method significantly outperforms state-of-the-art forecasting methods and effectively captures the relatedness to provide between-community knowledge transfer compared with other MTL methods. [ABSTRACT FROM AUTHOR]

Two Series-Connected Hybrid (SCH) magnets are under development at the National High Magnetic Field Laboratory. The first SCH is for the Helmholtz Centre Berlin (HZB) in Germany. The HZB SCH will be a horizontal bore, 30 T magnet and will be used for neutron scattering experiments. The second SCH is for the National High Magnetic Field Laboratory (NHMFL) in Tallahassee, FL. The NHMFL SCH will be a vertical bore, 36 T magnet. Both SCH Magnets combine a set of resistive Florida-Bitter coils with a superconducting outsert coil constructed of cable-in-conduit conductor (CICC). The two SCH magnets are designed for various operating scenarios including those with multiple ramp cycles at various rates. Both of the superconducting magnets are forced flow cooled with supercritical helium at 4.5 K. A standard refrigerator with a capacity of about 150-200 W at 4.5 K will be used to supply the cooling power and the forced mass flow rate. The cryogenic system of the SCH magnet consists of a helium refrigerator, a valve box with subcooler, a magnet cryostat and cryolines. In this paper, the design of the cryogenic system is described. [ABSTRACT FROM AUTHOR]

The National High Magnetic Field Laboratory (NHMFL) in Tallahassee, Florida has designed and is now constructing two Series Connected Hybrid (SCH) magnets, each connecting a superconducting outsert coil and a resistive Florida Bitter insert coil electrically in series. The SCH to be installed at the NHMFL will produce 36 T and provide 1 ppm maximum field inhomogeneity over a 1 cm diameter spherical volume. The SCH to be installed at the Helmholtz Center Berlin (HZB) in combination with a neutron source will produce 25 T to 30 T depending on the resistive insert. The two magnets have a common design for their cable-in-conduit conductor (CICC) and superconducting outsert coils. The CICC outsert coil winding packs have an inner diameter of 0.6 m and contribute 13.1 T to the central field using three grades of CICC conductors. Each conductor grade carries 20 kA and employs the same type of Nb3Sn superconducting wire, but each grade contains different quantities of superconducting wires, different cabling patterns and different aspect ratios. The cryostats and resistive insert coils for the two magnets are different. This paper discusses the progress in CIC conductor and coil fabrication over the last year including specification, qualification and production activities for wire, cable, conductor and coil processing. [ABSTRACT FROM AUTHOR]

The National High Magnetic Field Laboratory (NHMFL) has identified as one of its next high-field persistent-magnet targets a 21 T superconducting magnet system to be used in a Fourier Transform Ion Cyclotron Resonance (FT-ICR) Mass Spectrometer. The required fundamental parameters of a 21 T central field and 110 mm warm bore diameter are similar to those already successfully demonstrated in the NHMFL's Ultra-Wide Bore 900 MHz Nuclear Magnetic Resonance magnet system. However, there are several ancillary requirements of the FT-ICR spectrometer that require technical attention such as fringe field restrictions requiring shielding, length of uniformity zone, magnitude of inhomogeneity, horizontal orientation of the magnet axis and a limitation on the length of the cryostat. This paper describes the overall system requirements, features and status of the superconducting magnet conceptual design proposed for meeting these requirements. [ABSTRACT FROM AUTHOR]

The National High Magnetic Field Laboratory (NHMFL) has designed and is constructing a Series-Connected Hybrid (SCH) magnet system in Tallahassee, FL. Before the construction of the magnet system can begin many obstacles have to be solved through hardware design and winding practices. The hardware has to have the strength to handle the stresses of winding as well as retaining maximum functionality. The NHMFL will overcome these issues by running several analysis calculations and by producing three model coils for practicing functionality. Two model coils have been built and necessary changes to design and winding procedures have occurred through the practices. These changes will be presented and have been implemented into our winding procedures. [ABSTRACT FROM AUTHOR]

The National High Magnetic Field Laboratory is developing resistive-superconducting hybrid magnets both for internal use and for installation at other facilities. The Tallahassee magnet will have a vertical bore and provide 36 T in a 40-mm bore with 1-ppm homogeneity over a 10-mm diameter spherical volume. The Berlin version will provide a horizontal field of 25 T in a converging-diverging bore configuration suitable for neutron-scattering experiments. A design study is underway for a third magnet for Oak Ridge that will be similar to the Berlin version but provide >30 T. The three magnets will use very similar ∼13 T Nb3 Sn CICC coils for the superconducting outserts. The resistive insert magnets will be different configurations operating at different power levels. In designing the magnet systems we have developed a new numerical model to predict the critical current of Nb3 Sn CICC's, tested several conductors in-house and abroad, designed cryostats and refrigeration systems, and developed new resistive magnet technology. An overview of the innovations and present status is presented. [ABSTRACT FROM AUTHOR]

The National High Magnetic Field Laboratory (NHMFL) has been funded to design and construct two series-connected hybrids (SCH), one each for the NHMFL in Tallahassee, FL and the Helmholtz Centre Berlin for Materials and Energy (HZB), Germany. The original designs for both hybrids contained three concentric coils comprising a Nb3 Sn superconducting cable-in-conduit (CIC) main-field outsert coil, a resistive main-field insert coil and a NbTi superconducting CIC shield coil. The fringe field requirements for both facilities were met by designing the NbT1 shield coil to match the 9.6 x 106 A-m2 dipole moment of the main field coils at an average radius of 1.16 m. Subsequent, alternate magnetic shielding concepts for both hybrids have been investigated with the objective of reducing the anticipated $700 k NbTi shield coil cost. The HZB fringe field requirements were targeted to a local area of concern at the adjacent Spin Echo facility, centered 15.65 m from the hybrid magnet center. An alternate, lower-cost shield concept comprised a set of four smaller shield coils positioned orthogonally around the HZB spin echo facility with a resultant total 85% to 90% reduction in required dipole moment compared to the original NbTi shield coil. The fringe field requirements at the NHMFL were not changed, but a lower-cost iron shielding option (not described here) located around the NHMFL hybrid was found to be a viable alternative. As a result, the NbTi CIC coil can be eliminated from the common superconducting magnet design for both the HZB and the NHMFL SCH's in favor of viable lower cost shielding options. [ABSTRACT FROM AUTHOR]

The National High Magnetic Field Laboratory is developing several powered magnets employing novel configurations for use in photon and neutron scattering experiments. First is a split resistive magnet being built for Far-.--Infrared Scattering at the NHMFL in Tallahassee. This magnet has spurred the development of the novel Split Florida-Helix (SFH) technology. High-field test coils of the SF11 concept have been designed and built. Test results are presented. Second, Series-Connected Hybrid magnets with horizontal, conical bores are being designed for neutron scattering experiments at the Hahn-Meitner Institute in Berlin and the Spallation Neutron Source in Oak Ridge, TN. A new resistive magnet technology, the Conical Florida-Bitter (CFB), is being developed suitable for use as the resistive insert of these magnets. A high-field CFB test coil has been designed and is under construction. The conceptual design of the eventual hybrid system is presented along with the detailed design of the high-field test coil. [ABSTRACT FROM AUTHOR]

Reports on the Tallahassee, Florida-based National High Magnetic Field Laboratory's efforts on quench heaters design, simulation and analysis. Protection of large energy stored epoxy superconducting impregnated magnets; Insulation of heaters with winding by glass cloth; Advantage of split heaters over non split heaters in terms of the normalization time and extra redundancy.

Considers the cooling hole design in Bitter disks, a concept developed and tested at the National High Magnetic Field Laboratory (NHMFL). Background information on Bitter and polyhelix magnets; Cooling hole configuration; Application of the concept; Conclusions.

Details the design and operation of a 40-MW, highly stabilized power supply installed at the National High Magnetic Field Laboratory in Tallahassee, Florida. Specifications; Power circuit breaker and transformers; Passive filter; Rectifiers; Circuit diagram; Precommissioning tests.