Hydrogen Production from Photoelectrochemical Cells: Economic and Theoretical Considerations and Experimental Results

2012 ◽  
Keyword(s):  
Hydrogen Production ◽  
Experimental Results ◽  
Photoelectrochemical Cells ◽  
Theoretical Considerations

Modeling Hydroplaning and Effects of Pavement Microtexture

2005 ◽  
Vol 1905 (1) ◽  
pp. 166-176 ◽  
Author(s):  
G. P. Ong ◽  
T. F. Fwa ◽  
J. Guo
Keyword(s):  
Three Dimensional ◽  
Flow Simulation ◽  
Experimental Results ◽  
Tire Pressure ◽  
Finite Volume Model ◽  
Proposed Model ◽  
Loss Of Contact ◽  
The One ◽  
Theoretical Considerations ◽  
Good Agreement

Hydroplaning on wet pavement occurs when a vehicle reaches a critical speed and causes a loss of contact between its tires and the pavement surface. This paper presents the development of a three-dimensional finite volume model that simulates the hydroplaning phenomenon. The theoretical considerations of the flow simulation model are described. The simulation results are in good agreement with the experimental results in the literature and with those obtained by the well-known hydroplaning equation of the National Aeronautics and Space Administration (NASA). The tire pressure–hydroplaning speed relationship predicted by the model is found to match well the one obtained with the NASA hydroplaning equation. Analyses of the results of the present study indicate that pavement microtexture in the 0.2- to 0.5-mm range can delay hydroplaning (i.e., raise the speed at which hydroplaning occurs). The paper also shows that the NASA hydroplaning equation provides a conservative estimate of the hydroplaning speed. The analyses in the present study indicate that when the microtexture of the pavement is considered, the hydroplaning speed predicted by the proposed model deviates from the speed predicted by the smooth surface relationship represented by the NASA hydroplaning equation. The discrepancies in hydroplaning speed are about 1% for a 0.1-mm microtexture depth and 22% for a 0.5-mm microtexture depth. The validity of the proposed model was verified by a check of the computed friction coefficient against the experimental results reported in the literature for pavement surfaces with known microtexture depths.

scholarly journals Photoelectrochemical cells for solar hydrogen production: Challenges and opportunities

APL Materials ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 080901 ◽  
Author(s):  
Yi-Hsuan Chiu ◽  
Ting-Hsuan Lai ◽  
Ming-Yu Kuo ◽  
Ping-Yen Hsieh ◽  
Yung-Jung Hsu
Keyword(s):  
Hydrogen Production ◽  
Photoelectrochemical Cells ◽  
Solar Hydrogen ◽  
Challenges And Opportunities ◽  
Solar Hydrogen Production

scholarly journals Morphological sharpening of color images

2016 ◽  
Vol 64 (1) ◽  
pp. 103-113
Author(s):  
S. Skoneczny
Keyword(s):  
Color Images ◽  
Total Order ◽  
Experimental Results ◽  
Morphological Operations ◽  
Gray Level ◽  
Low Contrast ◽  
Novel Approach ◽  
Multivalued Images ◽  
Theoretical Considerations ◽  
Gray Level Images

Abstract This paper presents a novel approach to morphological contrast sharpening of image using the multilevel toggle operator. The concept presented here is a generalization of toggle based contrast operator for gray-level images. The multilevel toggle operator is used to enhance the contrast of multivalued images. In order to perform necessary morphological operations the modified pairwise ordering (MPO) algorithm is proposed. It gives the total order of color pixels. For comparison four other ordering methods are used. The main advantage of the proposed sharpener is its significant contrast enhancing ability when using MPO. Theoretical considerations as well as practical results are shown. Experimental results show its applicability to low-contrast color images.

Sustainable solar hydrogen production: from photoelectrochemical cells to PV-electrolyzers and back again

2014 ◽  
Vol 7 (7) ◽  
pp. 2056-2070 ◽  
Author(s):  
T. Jesper Jacobsson ◽  
Viktor Fjällström ◽  
Marika Edoff ◽  
Tomas Edvinsson
Keyword(s):  
Hydrogen Production ◽  
Theoretical Analysis ◽  
Photoelectrochemical Cells ◽  
Solar Hydrogen ◽  
Solar Hydrogen Production

A theoretical analysis of different device concepts for solar hydrogen production, demonstrating the close similarities between photoelectrochemical cells and PV-electrolyzers.

Marker Method in Studying the Defect Structure in Products of the Oxidation of Highly Disordered Substrates

2016 ◽  
Vol 35 (1) ◽  
pp. 21-28 ◽  
Author(s):  
Z. Grzesik ◽  
A. Poczekajlo ◽  
G. Smola ◽  
S. Mrowec
Keyword(s):  
Formation Mechanism ◽  
Point Defects ◽  
Defect Structure ◽  
Experimental Results ◽  
Theoretical Considerations

AbstractThe interpretation of marker experiments in studying the formation mechanism and defect structure of higher oxides during oxidation of lower oxides, showing rather high deviations from stoichiometry, has been discussed. It has been shown that correct results can be obtained only if the concentration of point defects in the substrate is taken into account. Theoretical considerations presented in this paper have been illustrated by the experimental results obtained during sulphidation of highly disordered Co1-yS to form CoS2, as well as Ni1-yS to form NiS2.

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