Evaluation of oxide ceramics as anodes for SOECs

2015 ◽  
Vol 182 ◽  
pp. 379-391 ◽  
Author(s):  
A. Egger ◽  
N. Schrödl ◽  
W. Sitte
Keyword(s):  
Prolonged Exposure ◽  
Electrode Structure ◽  
Polished Cross Section ◽  
Current Voltage ◽  
Post Test ◽  
Anodic Polarisation ◽  
Current Densities ◽  
Degradation Studies ◽  
Main Factor

La2NiO4+δ is characterised as an example for a potential anode material for high-temperature solid oxide electrolyser cells (SOECs). Short-term characterisation is performed from 700 °C to 850 °C between 0.01 and 1 bar oxygen partial pressure (pO2) on asymmetrical cells using Ce0.9Gd0.1O2−δ as the electrolyte. Long-term degradation studies over more than 3000 hours are conducted at 800 °C and 0.2 bar pO2 in dry and humid atmospheres with and without a Cr-source placed in close vicinity to the cell. The SOEC anode performance is investigated by current–voltage curves combined with impedance spectroscopy. Current densities of up to −410 mA cm−2 are applied in current–voltage measurements and during long-term degradation studies. A total increase in anode resistance by 350% is observed over the course of the degradation measurements in an increasingly harsh environment. Post-test analyses by SEM/EDX on a polished cross section of the cell show the presence of several contaminants in the electrode structure. However, chromium has not been identified by EDX even after prolonged exposure to Cr-sources in humid atmospheres, which is attributed to the anodic polarisation of the electrode. Electrode delamination appears to be the main factor for the strong loss in performance.

Critical Current Densities JC(H,T) and Current-Voltage Characteristics in Melt Processed Bi-2212 with and without Preferential Orientation

1992 ◽  
Vol 275 ◽  
Author(s):  
W. Paul ◽  
B. Heeb ◽  
Th. Baumann ◽  
M. Guidolin ◽  
L. J. Gauckler
Keyword(s):  
Critical Current ◽  
Bulk Material ◽  
Critical Currents ◽  
Zone Melting ◽  
Processed Material ◽  
Current Voltage ◽  
Small Fields ◽  
Current Densities ◽  
Current Voltage Characteristics

ABSTRACTIn contrast to sintered Bi2Sr2Ca1Cu2Oy (Bi-2212), melt processed material exhibits nonzero intergrain supercurrents at T < 77 K. By means of partial melting and long term annealing we achieved nonoriertted material with Jc(77) - 3500 A/cm2 (1μV/cm criterion) and Tc = 96 K. Zone melting leads to well textured bulk material with the c-axis of the crystallites oriented perpendicular to the pulling direction R, and thus to an anisotropie critical current density. The anisotropy factor is between 2 and 5. At low temperatures the melt textured ceramic exhibits higher critical currents than the nonoriented material. This is not true at high temperatures, since the latter has a higher critical temperature.At 77 K and small fields both oriented and nonoriented ceramics exhibit no transition in their current-voltage characteristics, but obey the power law E = Eo(j/jo(H)) α(H) over a large range in E (10”−3-10”−3 V/cm). Measurements on the textured ceramic with magnetic fields parallel and perpendicular to the pulling direction demonstrate that the superconducting properties of these materials are only affected by the field components parallel to the c-axes of the crystallites. For fields parallel to the pulling direction the measured values of α(H), Jo(H) and of the reversible magnetization Mrev can be attributed to the misorientation of the Bi-2212 platelets which is in average about 14°.

Apophysites – Revue de la littérature et ­nouvelles directions

2014 ◽  
Vol 62 (3) ◽  
Keyword(s):  
Scientific Evidence ◽  
Ossification Center ◽  
Health Staff ◽  
Optimal Management ◽  
Long Term Effect ◽  
High Incidence ◽  
Youth Athlete ◽  
Pathology Education ◽  
Main Factor

Apophysitis are part of the growth-related diseases within youth athlete population. Despite their high incidence within this growing cohort, many doubts remain. The physiopathology is still debated. Initially, the fragmentation of the ossification center was seen as the main factor of the disease. For few years, this theory has been questioned due to consistent signs of tendon suffering. Apophysitis may have some negative long-term effect on a sporting career. There is currently poor scientific evidence on the optimal management and no treatment has been widely accepted. Prevention remains the most powerful intervention in this particular pathology. Education of the athlete’s sporting entourage (family, coaches and health staff) and the athlete himself is necessary to act quickly and adapt the training load to decrease mechanical stress on the suffering apophysis.

scholarly journals Wittichenite semiconductor of Cu3BiS3 films for efficient hydrogen evolution from solar driven photoelectrochemical water splitting

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Dingwang Huang ◽  
Lintao Li ◽  
Kang Wang ◽  
Yan Li ◽  
Kuang Feng ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Water Splitting ◽  
Low Cost ◽  
Solar Hydrogen ◽  
Onset Potential ◽  
Term Stability ◽  
Long Term Stability ◽  
Solar Water Splitting ◽  
Current Densities

AbstractA highly efficient, low-cost and environmentally friendly photocathode with long-term stability is the goal of practical solar hydrogen evolution applications. Here, we found that the Cu3BiS3 film-based photocathode meets the abovementioned requirements. The Cu3BiS3-based photocathode presents a remarkable onset potential over 0.9 VRHE with excellent photoelectrochemical current densities (~7 mA/cm2 under 0 VRHE) and appreciable 10-hour long-term stability in neutral water solutions. This high onset potential of the Cu3BiS3-based photocathode directly results in a good unbiased operating photocurrent of ~1.6 mA/cm2 assisted by the BiVO4 photoanode. A tandem device of Cu3BiS3-BiVO4 with an unbiased solar-to-hydrogen conversion efficiency of 2.04% is presented. This tandem device also presents high stability over 20 hours. Ultimately, a 5 × 5 cm2 large Cu3BiS3-BiVO4 tandem device module is fabricated for standalone overall solar water splitting with a long-term stability of 60 hours.

scholarly journals Noise-Reducing Fabric Electrode for ECG Measurement

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4305
Author(s):  
Takamasa Terada ◽  
Masahiro Toyoura ◽  
Takahide Sato ◽  
Xiaoyang Mao
Keyword(s):  
Special Structure ◽  
Electrode Impedance ◽  
Electrode Structure ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Chip Type ◽  
Low Pass ◽  
Filter Fabric

In this work, we propose a fabric electrode with a special structure that can play the role of a noise reduction filter. Fabric electrodes made of the conductive fabric have been used for long-term ECG measurements because of their flexibility and non-invasiveness; however, due to the large impedance between the skin and the fabric electrodes, noise is easily introduced into the ECG signal. In contrast to conventional work, in which chip-type passive elements are glued to the electrode to reduce noise, the proposed electrode can obtain a noise-reduced ECG by changing the structure of fabric. Specifically, the proposed electrode was folded multiple times to form a capacitor with a capacitance of about 3 nF. It is combined with the skin-electrode impedance to form a low-pass filter. In the experiment, we made a prototype of the electrodes and measured ECG at rest and during EMG-induced exercise. As a result, the SNR values at rest and during exercise were improved about 12.02 and 10.29 , respectively, compared with the fabric electrode without special structure. In conclusion, we have shown that changing the fabric electrode structure effectively removes noise in ECG measurement.

scholarly journals Impact of Prolonged Exposure of Eleven Years to Hot Seawater on the Degradation of a Thermoset Composite

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2154
Author(s):  
Amir Hussain Idrisi ◽  
Abdel-Hamid I. Mourad ◽  
Muhammad M. Sherif
Keyword(s):  
Exposure Time ◽  
Prolonged Exposure ◽  
Mechanical Performance ◽  
Matrix Cracking ◽  
Pull Out ◽  
Strength Based ◽  
Different Temperatures ◽  
River Line ◽  
Composite Samples

This paper presents a long-term experimental investigation of E-glass/epoxy composites’ durability exposed to seawater at different temperatures. The thermoset composite samples were exposed to 23 °C, 45 °C and 65 °C seawater for a prolonged exposure time of 11 years. The mechanical performance as a function of exposure time was evaluated and a strength-based technique was used to assess the durability of the composites. The experimental results revealed that the tensile strength of E-glass/epoxy composite was reduced by 8.2%, 29.7%, and 54.4% after immersion in seawater for 11 years at 23 °C, 45 °C, and 65 °C, respectively. The prolonged immersion in seawater resulted in the plasticization and swelling in the composite. This accelerated the rate of debonding between the fibers and matrix. The failure analysis was conducted to investigate the failure mode of the samples. SEM micrographs illustrated a correlation between the fiber/matrix debonding, potholing, fiber pull-out, river line marks and matrix cracking with deterioration in the tensile characteristics of the thermoset composite.

scholarly journals Onset and Resolution of Key Adverse Events in Valbenazine-Treated Patients with Tardive Dyskinesia: Pooled Analyses from Two Long-Term Clinical Trials

CNS Spectrums ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 151-151
Author(s):  
Stephen R. Marder ◽  
Jean-Pierre Lindenmayer ◽  
Chirag Shah ◽  
Tara Carmack ◽  
Angel S. Angelov ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Adverse Events ◽  
Tardive Dyskinesia ◽  
Suicidal Behavior ◽  
Prolonged Exposure ◽  
First Occurrence ◽  
Balance Disorder ◽  
Clinical Interest ◽  
Post Hoc

AbstractObjectiveTardive dyskinesia (TD) is a persistent and potentially disabling movement disorder associated with prolonged exposure to antipsychotics and other dopamine receptor blocking agents. Long-term safety of the approved TD medication, valbenazine, was demonstrated in 2 clinical trials (KINECT 3 [NCT02274558], KINECT 4 [NCT02405091]). Data from these trials were analyzed post hoc to evaluate the onset and resolution of adverse events (AEs).MethodsParticipants in KINECT 3 and KINECT 4 received up to 48 weeks of once-daily valbenazine (40 or 80 mg). Data from these studies were pooled and analyzed to assess the incidence, time to first occurrence, and resolution for the following AEs of potential clinical interest: akathisia, balance disorder, dizziness, parkinsonism, somnolence/sedation, suicidal behavior/ideation, and tremor.ResultsIn the pooled population (N=314), all AEs of potential clinical interest occurred in <10% of participants, with somnolence (9.6%), suicidal behavior/ideation (6.4%), and dizziness (5.7%) being the most common AEs. Mean time to first occurrence ranged from 36 days (akathisia [n=9]) to 224 days (parkinsonism [n=2]). By end of study (or last study visit), resolution of AEs was as follows: 100% (suicidal ideation/behavior, parkinsonism); >85% (somnolence/sedation, dizziness); >70% (akathisia, balance disorder, tremor).ConclusionsIn long-term clinical trials, the incidence of AEs of potential clinical interest was low (<10%) and most were resolved by end of treatment (>70–100%). All patients taking valbenazine should be routinely monitored for AEs, particularly those that may exacerbate the motor symptoms associated with TD.FundingNeurocrine Biosciences, Inc.

scholarly journals Photoconduction of Polar and Nonpolar Cuts of Undoped Sr0.61Ba0.39Nb2O6 Single Crystals

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 780
Author(s):  
Elke Beyreuther ◽  
Julius Ratzenberger ◽  
Matthias Roeper ◽  
Benjamin Kirbus ◽  
Michael Rüsing ◽  
...  
Keyword(s):  
Electrical Measurement ◽  
Excitation Wavelength ◽  
Trap States ◽  
Strontium Barium Niobate ◽  
Strontium Barium ◽  
Current Voltage ◽  
History Of ◽  
A Current ◽  
Complex Manner

In the last two decades, variably doped strontium barium niobate (SBN) has attracted a lot of scientific interest mainly due to its specific non-linear optical response. Comparably, the parental compound, i.e., undoped SBN, appears to be less studied so far. Here, two different cuts of single-crystalline nominally pure strontium barium niobate in the composition Sr0.61Ba0.39Nb2O6 (SBN61) are comprehensively studied and analyzed with regard to their photoconductive responses. We present conductance measurements under systematically varied illumination conditions along either the polar z-axis or perpendicular to it (x-cut). Apart from a pronounced photoconductance (PC) already under daylight and a large effect upon super-bandgap illumination in general, we observe (i) distinct spectral features when sweeping the excitation wavelength over the sub-bandgap region as then discussed in the context of deep and shallow trap states, (ii) extremely slow long-term relaxation for both light-on and light-off transients in the range of hours and days, (iii) a critical dependence of the photoresponse on the pre-illumination history of the sample, and (iv) a current–voltage hysteresis depending on both the illumination and the electrical-measurement conditions in a complex manner.

Characterization and Fuel Cell Testing of Radiation-Grafted Psi Membranes

1999 ◽  
Vol 575 ◽  
Author(s):  
H.-P. Brack ◽  
M. M. Koebel ◽  
A. Tsukada ◽  
J. Huslage ◽  
F. Buechi ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Oxidative Stability ◽  
Screening Method ◽  
Exchange Capacity ◽  
Ex Situ ◽  
Active Area ◽  
Rapid Screening ◽  
Raman Spectroscopic ◽  
Current Voltage

ABSTRACTWe have demonstrated earlier the useful performance of our PSI radiation-grafted membranes in terms of the current-voltage characteristics of 30 cm2 active area fuel cells containing these membranes and their long-term testing over 6,000 h at 60 °C. We report here on testing of PSI radiation-grafted membranes in these fuel cells at 80 °C and in short stacks comprised of two or four 100 cm2 active area cells. The in-situ degradation of membranes has been investigated by characterizing membranes both before testing in fuel cells and post-mortem after testing in fuel cells. Characterization was accomplished by means of ion-exchange capacity and infrared and Raman spectroscopic measurements. In addition, a rapid screening method for our ex-situ testing of the oxidative stability of proton-conducting membranes was developed in this work. Comparison of the initial screening test results concerning the oxidative stability of some perfluorinated, partially-fluorinated, and non-fluorinated membranes compare well qualitatively with the relative stability of these same membranes during their long-term testing in fuel cells.

A Study of Pt/AlN/6H-SiC MIS Structures for Device Applications

2000 ◽  
Vol 622 ◽  
Author(s):  
Margarita P. Thompson ◽  
Gregory W. Auner ◽  
Changhe Huang ◽  
James N. Hilfiker
Keyword(s):  
Plasma Source ◽  
Film Structure ◽  
Low Leakage ◽  
Low Leakage Current ◽  
Current Voltage ◽  
Aln Film ◽  
Capacitance Voltage ◽  
Device Applications ◽  
Current Densities ◽  
Mis Structures

ABSTRACTAlN films with thicknesses from 53 to 79 nm were deposited on 6H-SiC substrates via Plasma Source Molecular Beam Epitaxy (PSMBE). The influence of deposition temperature on the growth mode and film roughness was assessed. The optical constants of the films in the range 0.73-8.75 eV were determined using spectroscopic ellipsometry. Pt/AlN/6H-SiC MIS structures were created and current-voltage (I-V) and capacitance-voltage (C-V) measurements were performed at room temperature and at 250°C. Most of the MIS structures showed rectifying I-V characteristics regardless of growth temperature. A 120-nm-thick AlN film was deposited at 500°C. MIS structures created on this film showed a very low leakage current densities of 6×10−8 A/cm2. The dielectric constant of the film was estimated at approximately 9. The relation between film structure and electrical properties of the films is discussed.

scholarly journals Efficacy of a bystander intervention for preventing dating violence in Brazilian adolescents: short-term evaluation

2019 ◽  
Vol 32 (1) ◽  
Author(s):  
Karine Brito dos Santos ◽  
Sheila Giardini Murta ◽  
Luis Gustavo do Amaral Vinha ◽  
Juliana Silva de Deus
Keyword(s):  
Romantic Relationships ◽  
Dating Violence ◽  
Control Group ◽  
Short Term ◽  
Brazilian Sample ◽  
Post Test ◽  
Short Term Evaluation ◽  
Term Evaluation ◽  
Brazilian Culture

Abstract Peers are the preferred source of help for Brazilian adolescents who experience dating violence. However, they are not always the best informants for effective responses for dealing with situations of violence in romantic relationships among peers. This experimental study aimed to evaluate the short-term efficacy of three aspects of a peer- and bystander approach-based intervention: the intent to offer help, empathy, and bystander attitudes in response to dating violence in a Brazilian sample of adolescents. The study’s participants were 33 adolescents randomized in two groups: experimental group (EG, n = 14) and control group (CG, n = 19). The EG underwent three weekly intervention sessions of 90 min each on the healthy versus violent romantic relationships, the quality of friendship in the peer network, and the role of the bystander, while the CG received no intervention. Evaluations were performed 1 week before and two and half months after the intervention. Statistically significant differences between EG and CG at post-test were not found in intention to help, empathy, and bystander attitudes. Future studies should include evaluations of larger samples and mid- and long-term follow-ups to identify patterns of change over the long term as well as examine barriers to utilization of bystander behaviors by adolescents in Brazilian culture.

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