scholarly journals Redox Cycling for SOFC Accelerated Degradation

2022 ◽  
Vol 334 ◽  
pp. 04015
Author(s):  
Daria Vladikova ◽  
Blagoy Burdin ◽  
Asrar Sheikh ◽  
Paolo Piccardo ◽  
Milena Krapchanska ◽  
...  
Keyword(s):  
Artificial Aging ◽  
Impedance Analysis ◽  
Redox Cycling ◽  
Stress Tests ◽  
Accelerated Degradation ◽  
Redox Cycles ◽  
Oxidation Reduction ◽  
Impedance Monitoring ◽  
Formation Of Cracks ◽  
And Migration

This work aims at development of Accelerated Stress Tests for SOFC via artificial aging of the fuel electrode applying chemical and electrochemical (hydrogen starvation) redox cycling. In principle the degradation processes follows that of calendar aging (Ni coarsening and migration), but in addition it can bring to irreversible damages caused by the development of cracks at the interface anode/electrolyte due to the expansion/shrinkage of the Ni network. The challenge is to introduce conditions which will prevent the formation of cracks which can be done by partial oxidation. The advantage of the proposed methodology is that a mild level of oxidation can be regulated by direct impedance monitoring of the Ni network resistance changes during oxidation/reduction. Once the redox cycling conditions are fixed on bare anode and checked on anode/electrolyte sample for eventual cracks, the procedure can be introduced for AST in full cell configuration. The developed methodology is evaluated by comparative impedance analysis of artificially aged and calendar aged button cells. The results for 20 redox cycles which can be performed for 24 hours are comparable with those obtained for about 1600 hours operation in standard conditions which ensures more than 50 times acceleration.

Degradation Mechanism of III-V Triple Junction Solar Cells Analyzed Using Step Stress Tests

2013 ◽  
Vol 284-287 ◽  
pp. 281-286 ◽  
Author(s):  
Hwen Fen Hong ◽  
Jin Wei ◽  
Mei Hui Chiang ◽  
Zun Hao Shih ◽  
Wu Yih Uen ◽  
...  
Keyword(s):  
Solar Cells ◽  
Triple Junction ◽  
Fill Factor ◽  
Degradation Mechanism ◽  
Depletion Region ◽  
Open Circuit ◽  
Protective Film ◽  
Stress Tests ◽  
Accelerated Degradation ◽  
Recombination Current

We analyzed the degradation mechanism of GaInP/GaInAs/Ge triple junction solar cells without coating any protective film. Gradual degradation in the dark and light I-V characteristics of the solar cells were observed after the step stress accelerated degradation tests (SSADT) were conducted on these devices sequentially at 90, 110, 130 and 150°Cfor 25, 55, 85 and 135 hours, respectively. The recombination current in the depletion region at the chip perimeter of solar cells, resulting in the decrease of open-circuit voltage (VOC), fill factor (FF) and efficiency, is suggested to be the important degradation mechanism for GaInP/GaInAs/Ge triple junction solar cells.

scholarly journals Distribution of iron and iron compounds in the Kemeri - Jaunkemeri occurence of sulphide water

2015 ◽  
Vol 2 ◽  
pp. 244
Author(s):  
Janis Prols ◽  
Ērika Teirumnieka ◽  
Edmunds Teirumnieks
Keyword(s):  
Organic Matter ◽  
Groundwater Modeling ◽  
Organic Matter Content ◽  
Matter Content ◽  
Iron Compounds ◽  
Migration Forms ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
And Migration ◽  
Formation Of Complexes

Iron concentrations, distribution and migration forms, depending on pH and oxidation – reduction potential, were analyzed in case of the Kemeri-Jaunkemeri occurrence (area about 240 km<sup>2</sup>) of sulphide containing water (maximal sulphides concentration – 74 mg/l), located in Latvia. Iron content was investigated in 457 wells located within all area of occurrence. Those wells were installed to two aquifers: the Quarternary multi-aquifer and Salaspils aquifer, where occurrence of sulphide containing groundwater is distributed. All groundwater of occurrence is classified in four types depending on oxygen, sulphides and organic matter content in the groundwater.  Modeling of groundwater migration forms was carried out, and it is stated that iron migrates basically as Fe<sup>2+</sup> in oxygen and suphides non-containing water. Migration forms are influenced by concentration of organic matter in the aquifer. The portion of Fe<sup>2+</sup> migrating in a form of free decreases due to formation of complexes with fulvic and humic acids, which can reach 36.5% of all migration forms. Iron migrates as Fe(OH)<sub>3</sub>  in oxygen containing water (more than 99% of determined forms). Presence of iron is ascertained also in sulphides containing water, where iron migrates basically as (98.8% of determined forms).  This occurs due to formation of complexes with sulphydes – FeHS<sup>-</sup> and Fe(HS)<sub>2</sub><sup>o</sup>.

scholarly journals DISTRIBUTION OF IRON AND IRON COMPOUNDS IN THE KEMERI - JAUNKEMERI OCCURENCE OF SULPHIDE WATER

2015 ◽  
Vol 2 ◽  
Author(s):  
Janis Prols
Keyword(s):  
Organic Matter ◽  
Groundwater Modeling ◽  
Organic Matter Content ◽  
Matter Content ◽  
Iron Compounds ◽  
Migration Forms ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
And Migration ◽  
Formation Of Complexes

<p class="R-AbstractKeywords"><span lang="EN-US">Iron concentrations, distribution and migration forms, depending on pH and oxidation – reduction potential, were analyzed in case of the Kemeri-Jaunkemeri occurrence (area about 240 km2) of sulphide containing water (maximal sulphides concentration – 74 mg/l), located in Latvia. Iron content was investigated in 457 wells located within all area of occurrence. Those wells were installed to two aquifers: the Quarternary multi-aquifer and Salaspils aquifer, where occurrence of sulphide containing groundwater is distributed. All groundwater of occurrence is classified in four types depending on oxygen, sulphides and organic matter content in the groundwater.  Modeling of groundwater migration forms was carried out, and it is stated that iron migrates basically as Fe2+ in oxygen and suphides non-containing water. Migration forms are influenced by concentration of organic matter in the aquifer. The portion of Fe2+ migrating in a form of free decreases due to formation of complexes with fulvic and humic acids, which can reach 36.5% of all migration forms. Iron migrates as Fe(OH)3  in oxygen containing water (more than 99% of determined forms). Presence of iron is ascertained also in sulphides containing water , where iron migrates basically as (98.8% of determined forms).  This occurs due to formation of complexes with sulphydes – FeHS- and Fe(HS)2o.</span></p>

Solar thermochemical conversion of CO2 into fuel via two-step redox cycling of non-stoichiometric Mn-containing perovskite oxides

2015 ◽  
Vol 3 (7) ◽  
pp. 3536-3546 ◽  
Author(s):  
Antoine Demont ◽  
Stéphane Abanades
Keyword(s):  
Metal Oxide ◽  
Perovskite Oxides ◽  
Redox Cycling ◽  
Lanthanum Manganite ◽  
Thermochemical Conversion ◽  
Redox Cycles ◽  
Solar Thermochemical ◽  
A Site ◽  
Manganite Perovskites

A-site and B-site substituted lanthanum manganite perovskites were synthesized and characterized for application in two-step metal oxide redox cycles for thermochemical splitting of CO2.

scholarly journals Ion Accumulation and Migration Effects on Redox Cycling in Nanopore Electrode Arrays at Low Ionic Strength

ACS Nano ◽  
2016 ◽  
Vol 10 (3) ◽  
pp. 3658-3664 ◽  
Author(s):  
Chaoxiong Ma ◽  
Wei Xu ◽  
William R. A. Wichert ◽  
Paul W. Bohn
Keyword(s):  
Ionic Strength ◽  
Redox Cycling ◽  
Ion Accumulation ◽  
Electrode Arrays ◽  
And Migration ◽  
Low Ionic Strength ◽  
Nanopore Electrode

scholarly journals Estimating Cold Stress in `Beautiful Arcade' Apple Roots using Electrical Impedance Analysis

1996 ◽  
Vol 6 (1) ◽  
pp. 54-58 ◽  
Author(s):  
Jean-Pierre Privé ◽  
M.I.N. Zhang
Keyword(s):  
Electrical Conductivity ◽  
Cold Stress ◽  
Electrical Impedance ◽  
Vital Staining ◽  
Impedance Analysis ◽  
Freezing Injury ◽  
Stress Tests ◽  
Tetrazolium Chloride ◽  
Freeze Thaw ◽  
Two Parameters

2,3,5-triphenyl tetrazolium chloride (TTC) staining, electrical conductivity, and electrical impedance (Z) analyses were used to assess freezing injury of `Beautiful Arcade' apple (Malus ×domestica Borkh.) roots taken in late March from either the field or 3C-refrigerated storage (cold-stored). Lethal temperature (LT50) levels using TTC or electrical conductivity occurred at colder temperatures than those found using Z. Techniques varied in their ability to detect changes in cell viability with increasing cold stress. Listed in order of decreasing responsiveness they are electrical impedance (Z), electrical conductivity, and TTC vital staining. With the most sensitive technique, Z, two parameters—extracellular and total tissue electrical resistance—were about five and eight times lower (indicating more injury) for roots from the field than from cold storage. The smaller values obtained from the field roots were probably due to natural in-field freeze-thaw cycling before the controlled cold-stress tests in the laboratory. More importantly, the impedance technique provided more detailed information than TTC or electrical conductivity about how apple roots respond to cold stress and how Z may provide some insight into freeze-thaw history before injury assessment. Although this technique shows potential, future studies are required to render a complete physiological significance to the impedance parameters involved in calculating Z.

scholarly journals ДОСЛІДЖЕННЯ ОСОБЛИВОСТЕЙ ПРИСКОРЕНОГО РОЗКЛАДУ ВТОРИННИХ ПОЛІОЛЕФІНІВ

2018 ◽  
Vol 122 (3) ◽  
pp. 32-37
Author(s):  
Н. В. Сова ◽  
Б. М. Савченко ◽  
В. Г. Хоменко ◽  
О. В. Талалай
Keyword(s):  
Artificial Aging ◽  
Constant Pressure ◽  
Strength Properties ◽  
Ash Content ◽  
Capillary Viscometer ◽  
Efficient Technology ◽  
X Ray ◽  
Accelerated Degradation ◽  
Aging Conditions

Investigation of the features and conditions of accelerated degradation of films based on PE wastes to create and develop an efficient technology for the utilization of flexible polyolefin packaging. The chemical composition of the inorganic residue after the burning of polymers wastes was determined by X-ray fluorescence method. The determination of the MFI of PE was carried out in accordance with ISO 1133: 1997 on a capillary viscometer of constant pressure at a temperature (190 ± 0.5) °С and a weight of 2,16 kg. Deformation-strength properties - according to ASTM D638. Ash content - according to ISO 3451-2: 1998 «Plastics. Determination of ash content». The ability to accelerate the degradation of polyolefine wastes in an environment was established. The changes of mechanical properties of PE films of different composition in conditions of artificial aging were investigated. The ability of calcium carbonate to exhibit the effect of oxide additives in PE films during the aging process was revealed. The features of accelerated degradation of polyolefine wastes in artificial aging conditions were first discovered and investigated. Obtained initial data for the production of PE film technology based on polyolefine wastes, then capable of accelerated degradation under environmental conditions

scholarly journals Imitation of Cold Stress in `Beautiful Arcade' Apple Root using Electrical Impedance Analysis

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 774F-775
Author(s):  
Jean-Pierre Prive ◽  
M.I.N. Zhang
Keyword(s):  
Cold Stress ◽  
Electrical Resistance ◽  
Electrical Impedance ◽  
Impedance Analysis ◽  
Stress Tests ◽  
Triphenyltetrazolium Chloride ◽  
Freeze Thaw ◽  
Impedance Technique ◽  
Two Parameters ◽  
Total Tissue

2,3,5-triphenyltetrazolium chloride (TTC) staining and electrical impedance (?) analyses of apple roots (Malus domestica Borkh. `Beautiful Arcade') taken in late March from either the field or from 3C refrigerated storage (cold-stored). LT50 levels using TTC were much lower than those found using electrical impedance. No loss of viability in the roots was detectable using TTC staining until a freeze–thaw stress of –9C whereas? analysis detected changes in cell viability after a freeze–thaw stress of only –3C. With increasing cold stress, two parameters: extracellular electrical resistance (Ro) and time constant?, decreased linearly for cold-stored roots and exponentially for field roots. Impedance analysis also revealed that the values for both extracellular Ro and total tissue electrical resistance (R?) for the field roots were approximately 5 and 8 times lower, respectively, than in the cold-stored roots. It is believed that the smaller Ro and R? values obtained from the field roots were due to natural in-field freeze–thaw cycling prior to the controlled stress tests in the laboratory. Based on the analyses of winter hardiness using the two methods, the impedance technique? provided the physiological information not only about the hardiness level, but also about freeze–thaw history prior to the hardiness assessment.

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