In recent years many large scale demonstrators and prototypes of superconducting fault current limiters have been successfully developed and tested. Within the European Project ECCOFLOW ...(www.eccoflow.org), it is the first time that a resistive-type superconducting fault current limiter is developed for two different locations and that a permanent installation is foreseen. The limiter has a rating of 20 kV and 1 kA and will be tested in a busbar and transformer feeder application. The paper summarizes the conceptual design of this innovative limiter and reports in detail about the development of the super- conducting limiting elements, their integration into a cryostat and the design of the whole limiter including cooling and grid integration. As a main result it can be summarized that the ECCOFLOW limiter fulfills all requirements according to the two different specifications. Approximately 3 km of 12 mm wide YBCO tape will be used to realize a three phase system.
Within the EU-funded project FastGrid a resistive superconducting fault current limiter for DC-application is actually under development. To reduce substantially the amount of deployed ...superconducting tape an increase of voltage per length in the limitation case is needed. Moreover, the resistive transition (quench) should be fast and uniform. In the present work, the thermal behavior of three different architectures of coated conductors are investigated by means of transient simulations. The first architecture is composed by an additional Hastelloy shunt layer, which is supposed to avoid overheating of the conductor during fault limitation. The other architectures include layers of silver and copper as stabilizers. Our parameter study including the geometries of the different layers and the inhomogeneity of the critical current density of the superconducting tape shall lead to an optimized tape layout. First comparisons with experiment indicate, that, with the first architecture, electric field strength up to 100 V/m should be within reach.
It has been shown that theta (6-10 Hz) and delta (1-6 Hz) ongoing electroencephalographic (EEG) rhythms revealed variations in the cortical arousal in C57 Wild Type (WT) mice during cage exploration ...(active condition) compared to awake quiet behavior (passive condition; IMI PharmaCog project, www.pharmacog.eu).
The objective was to test if these EEG rhythms might be abnormal in old PDAPP mice modeling Alzheimer's disease (AD) with a hAPP Indiana V717F mutation (They show abnormal neural transmission, cognitive deficits, and brain accumulation of Aβ1-42).
Ongoing EEG rhythms were recorded by a frontoparietal bipolar channel in 15 PDAPP and 23 WT C57 male mice (mean age of 22.8 months ±0.4 and 0.3 standard error, respectively). EEG absolute power (density) was calculated. Frequency and amplitude of individual delta and theta frequency (IDF and ITF) peaks were considered during passive and active states in the wakefulness.
Compared with the WT group, the PDAPP group showed higher frequency of the IDF during the passive condition and lower frequency of the ITF during the active state. Furthermore, the WT but not PDAPP group showed significant changes in the frontoparietal EEG power (IDF, ITF) during active over passive state.
PDAPP mice were characterized by less changes in the brain arousal during an active state as revealed by frontoparietal EEG rhythms. Future studies will have to cross-validate the present results on large animal groups, clarify the neurophysiological underpinning of the effect, and test if the disease modifying drugs against AD amyloidosis normalize those candiate EEG biomarkers in PDAPP mice.
The air coil superconducting fault current limiter consists of two major parts: A primary copper winding and a secondary superconducting winding, made of short-circuited (RE)BCO tapes. Both windings ...are inductively coupled solenoids. The presented design method enables retrofitting existing, conventional shunt reactors with a secondary superconducting winding. The advantage of the retrofit is a low impedance during normal operation. This lowered impedance depends on different parameters, such as the critical current of the used superconducting tape or the distance between the windings. A calculation example shows that the impedance of a conventional shunt reactor can be lowered from 6% to 2.4% during normal operation and remains roughly the same during fault current limiting.
► We installed 3-phase superconducting current limiter for 12kV, 533A in a real grid. ► ENSYSTROB is the so far largest resistive superconducting current limiter world wide. ► Our superconducting ...current limiter ENSYSTROB is based on YBCO coated conductors. ► We showed that the AC losses of the ENSYSTROB current limiter are negligible. ► We compared two material options, YBCO tapes and bulk BSCCO, for current limiters.
Within the German project ENSYSTROB a 3-phase resistive fault current limiter for medium voltage applications (12kV, 533Arms) was designed, built, tested and installed in the grid for a one year’s field test. The superconducting modules are made of YBCO coated conductors and replace the modules of an already successfully tested limiter on the basis of BSCCO 2212 bulk material. The components are multifilar spirals equipped with pairs of 12mm wide YBCO tapes. The single components were characterized with respect to critical current, AC losses and limitation behavior under all possible operation conditions. The finally mounted limiter was successfully tested with respect to high voltage and limitation according to the standards of the customer. It is now installed and operating in its field test location. Finally we give a first comparison of both materials with respect to the different operational aspects.
For a transformer, the annual energy loss depends on the load-dependent efficiency of the transformer and the characteristic load curve at the specific location in the grid or elsewhere. The goal of ...this work is the comparison of the efficiency and the annual energy losses of a superconducting (from 2G high temperature superconductors) and conventional transformer. The calculations of the load-dependent efficiency for both transformers are performed referring to a real case application of a power transformer in a power plant which defines the load curve of the device. For the conventional transformer the data base of an industrial product was used, whereas for the superconducting transformer a conceptional design for the selected specific application was developed and used for the calculations of the load-specific efficiencies and annual energy losses using the characteristic load curve of the selected application. The results show, that superconducting transformers made from high temperature superconductors (Coated Conductors), could have up to 80 percent less annual energy losses compared to the conventional transformer made from copper wires.
Long-term sequelae are frequent and often disabling after epidermal necrolysis (Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN)). However, consensus on the modalities of ...management of these sequelae is lacking.
We conducted an international multicentric DELPHI exercise to establish a multidisciplinary expert consensus to standardize recommendations regarding management of SJS/TEN sequelae.
Participants were sent a survey via the online tool "Survey Monkey" consisting of 54 statements organized into 8 topics: general recommendations, professionals involved, skin, oral mucosa and teeth, eyes, genital area, mental health, and allergy workup. Participants evaluated the level of appropriateness of each statement on a scale of 1 (extremely inappropriate) to 9 (extremely appropriate). Results were analyzed according to the RAND/UCLA Appropriateness Method.
Fifty-two healthcare professionals participated. After the first round, a consensus was obtained for 100% of 54 initially proposed statements (disagreement index < 1). Among them, 50 statements were agreed upon as 'appropriate'; four statements were considered 'uncertain', and ultimately finally discarded.
Our DELPHI-based expert consensus should help guide physicians in conducting a prolonged multidisciplinary follow-up of sequelae in SJS-TEN.
The possible out-of-season effect of beta-carotene supplementation on ovulation rate (OR), antral follicles (AFN), and total ovarian activity (TOA = OR + AFN) as related to the LH release pattern in ...yearling anestrous goats was evaluated. In late April, Alpine-Saanen-Nubian x Criollo goats (
= 22, 26 N) were randomly allotted to: (1) Beta-carotene (BETA;
= 10, orally supplemented with 50 mg/goat/d; 36.4 ± 1.07 kg live weight (LW), 3.5 ± 0.20 units, body condition score (BCS) or (2) Non-supplemented (CONT;
= 12, 35.2 ± 1.07 kg LW, 3.4 ± 0.2 units BCS). Upon estrus synchronization, an intensive blood sampling (6 h × 15 min) was accomplished in May for LH quantifications; response variables included (pulsatility-PULSE, time to first pulse-TTFP, amplitude-AMPL, nadir-NAD and area under the curve-AUC). Thereafter, an ultrasonography scanning was completed to assess OR and AFN. The Munro algorithm was used to quantify LH pulsatility; if significant effects of time, treatment or interaction were identified, data were compared across time. Neither LW nor BCS (
> 0.05) or even the LH (
> 0.05); PULSE (4.1 ± 0.9 pulses/6 h), NAD (0.47 ± 0.13 ng) and AUC (51.7 ± 18.6 units) differed between treatments. Nonetheless, OR (1.57 vs. 0.87 ± 0.18 units) and TOA (3.44 vs. 1.87 ± 0.45 units) escorted by a reduced TTFP (33 vs. 126 ± 31.9 min) and an increased AMPL (0.55 vs. 0.24 ± 0.9 ng), favored to the BETA supplemented group (
< 0.05), possibly through a GnRH-LH enhanced pathway and(or) a direct effect at ovarian level. Results are relevant to speed-up the out-of-season reproductive outcomes in goats while may embrace translational applications.
▶ Above/below canopy eddy covariance CO
2/H
2O fluxes in a hemiboreal forest ecosystem. ▶ Reactive trace gases quantified. ▶ BVOC fluxes from soil and leaves monitored.
During two measurement ...campaigns, from August to September 2008 and 2009, we quantified the major ecosystem fluxes in a hemiboreal forest ecosystem in Järvselja, Estonia. The main aim of this study was to separate the ecosystem flux components and gain insight into the performance of a multi-species multi-layered tree stand. Carbon dioxide and water vapor fluxes were measured using the eddy covariance method above and below the canopy in conjunction with the microclimate. Leaf and soil contributions were quantified separately by cuvette and chamber measurements, including fluxes of carbon dioxide, water vapor, nitrogen oxides, nitrous oxide, methane, ozone, sulfur dioxide, and biogenic volatile organic compounds (isoprene and monoterpenes). The latter have been as well characterized for monoterpenes in detail. Based on measured atmospheric trace gas concentrations, the flux tower site can be characterized as remote and rural with low anthropogenic disturbances.
Our results presented here encourage future experimental efforts to be directed towards year round integrated biosphere–atmosphere measurements and development of process-oriented models of forest–atmosphere exchange taking the special case of a multi-layered and multi-species tree stand into account. As climate change likely leads to spatial extension of hemiboreal forest ecosystems a deep understanding of the processes and interactions therein is needed to foster management and mitigation strategies.
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