Anomalous Warburg Impedance: Influence of Uncompensated Solution Resistance

2011 ◽  
Vol 115 (24) ◽  
pp. 12232-12242 ◽  
Author(s):  
Shruti Srivastav ◽  
Rama Kant
Keyword(s):  
Warburg Impedance ◽  
Solution Resistance

Performance of Wood Flooring UV Coatings Interfacial Modified by Nano-Silica

2014 ◽  
Vol 609-610 ◽  
pp. 118-123
Author(s):  
Xiao Xing Yan ◽  
Guo Yue Xu ◽  
Yan Wu ◽  
Zhi Hui Wu
Keyword(s):  
Impact Strength ◽  
High Speed ◽  
Sodium Hydroxide Solution ◽  
Sound Insulation ◽  
Drying Time ◽  
Uv Curable ◽  
Aqueous Sodium ◽  
Wood Flooring ◽  
Solution Resistance ◽  
Uv Coating

Cork flooring maintains the natural qualities of cork, showing the unique and elegant natural patterns, and also has series of advantages such as thermal insulation, sound insulation, moisture barrier, insulation, and no static. Ultraviolet (UV) curable coatings have no volatile organic compounds, little environmental pollution, fast curing, and are suitable for high speed automated production, which is the development of environmentally friendly wood floor coatings. In this paper, the UV-curable wooden coatings for floor were interfacially modified with nanosilica. The process parameters were optimized by orthogonal experiments, and the overall performance of wood flooring UV coating was obtained. The mechanical properties of the coating (hardness, adhesion and impact strength), resistance to liquid properties (resistance to aqueous sodium chloride solution, resistance to aqueous sodium hydroxide solution, resistance to alcohol, resistance to blue and black ink, resistance to sauce) and gloss were tested. It was found that wood flooring UV coating had good performance, hardness reached 3H, adhesion reached one grade, impact strength was 40 kgcm, and fluid-resistant performance (120 h) of coating reached one grade when the nanosilica content was 0.50%~0.70%, the drying time was 2 min, and medium pressure mercury UV lamp was 3. The gloss results showed that gloss of wood flooring UV coatings decreased with the increase of nanosilica content. When the nanosilica content was 0.50%~0.70%, the gloss value was in the vicinity of 35%, showing a matte gloss. This study provides new perspectives in wood flooring UV coating for industrial applications.

Study of Alternating Current Impedance of Basic Magnesium Sulfate Cement

2017 ◽  
Vol 896 ◽  
pp. 97-103 ◽  
Author(s):  
Wen Hai Chen ◽  
Cheng You Wu ◽  
Hui Fang Zhang ◽  
Wu Yu Zhang ◽  
Bo Kun Chen ◽  
...  
Keyword(s):  
Magnesium Sulfate ◽  
Alternating Current ◽  
Molar Ratio ◽  
Impedance Spectra ◽  
Early Hydration ◽  
Straight Line ◽  
Steel Protection ◽  
Magnesium Oxysulfate ◽  
Solution Resistance ◽  
Hydration Phases

Alternating current impedance has been used to study effects of hydration stages and molar ratio on the pore structure and hydration characters of basic magnesium sulfate cement. The alternating current impedance spectra of at early hydration almost appears as a straight line because none crystal hydration phases form. And it appears high frequency semicircle at late hydration stage because of decreasing of porosity and amount of 5Mg (OH)2 ·MgSO4·7H2O gradually form with ages. Besides, alternating current impedance spectra differences among basic magnesium sulfate, magnesium oxysulfate and magnesium oxychloride cement have been studied. These differences indicate that additives such as citric acid may change the structure and charge characteristics of MgO hydration layer which make tends to form more 5Mg (OH)2 ·MgSO4·7H2O phase in basic magnesium sulfate cement than that in magnesium oxysulfate cement. The higher pore solution resistance of BMS cement is the main factor of better steel-protection.

scholarly journals Electrochemical Performance Measurements of PBI-Based High-Temperature PEMFCs

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Javier Parrondo ◽  
Chitturi Venkateswara Rao ◽  
Sundara L. Ghatty ◽  
B. Rambabu
Keyword(s):  
Fuel Cell ◽  
Electrochemical Performance ◽  
Electrochemical Impedance ◽  
Gas Diffusion ◽  
Cell Polarization ◽  
Membrane Electrode ◽  
Performance Measurements ◽  
Transfer Resistance ◽  
Warburg Impedance ◽  
Overall Resistance

Acid-doped poly(2,2′-m-phenylene-5,5′-bibenzimidazole) membranes have been prepared and used to assemble membrane electrode assemblies (MEAs) with various contents of PBI (1–30 wt.%) in the gas diffusion electrode (GDE). The MEAs were tested in the temperature range of140∘C–200∘C showing that the PBI content in the electrocatalyst layer influences strongly the electrochemical performance of the fuel cell. The MEAs were assembled using polyphosphoric acid doped PBI membranes having conductivities of 0.1 Scm−1at180∘C. The ionic resistance of the cathode decreased from 0.29 to 0.14 Ohm-cm2(180∘C) when the content of PBI is varied from 1 to 10 wt.%. Similarly, the mass transfer resistance or Warburg impedance increased 2.5 times, reaching values of 6 Ohm-cm2. 5 wt.% PBI-based MEA showed the best performance. The electrochemical impedance measurements were in good agreement with the fuel cell polarization curves obtained, and the optimum performance was obtained when overall resistance was minimal.

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