Surface Area Loss of Platinum Supported on Carbon in Phosphoric Acid Electrolyte

1980 ◽  
Vol 127 (6) ◽  
pp. 1219-1224 ◽  
Author(s):  
G. A. Gruver ◽  
R. F. Pascoe ◽  
H. R. Kunz
Keyword(s):  
Phosphoric Acid ◽  
Surface Area ◽  
Acid Electrolyte ◽  
Area Loss

scholarly journals Surface Area Loss of Platinum Alloy Supported on Carbon in Concentrated Phosphoric Acid at Low Potentials

1996 ◽  
Vol 64 (6) ◽  
pp. 431-435
Author(s):  
Tadanori MAOKA ◽  
Mitushi UENO ◽  
Takeshi KUWABARA ◽  
Hisao NISHIKAWA
Keyword(s):  
Phosphoric Acid ◽  
Surface Area ◽  
Platinum Alloy ◽  
Area Loss

scholarly journals Disorders of the erythrocyte membrane

2015 ◽  
Vol 9 (4) ◽  
pp. 323
Author(s):  
Sophia Delicou ◽  
Aikaterini Xydaki ◽  
Chryssanthi Kontaxi ◽  
Konstantinos Maragkos
Keyword(s):  
Surface Area ◽  
Erythrocyte Membrane ◽  
Structural Integrity ◽  
Mechanical Stability ◽  
Hereditary Spherocytosis ◽  
Membrane Surface ◽  
Membrane Skeleton ◽  
Inherited Disorders ◽  
Hereditary Elliptocytosis ◽  
Area Loss

Hemolytic anemia due to abnormalities of the erythrocyte membrane comprises an important group of inherited disorders. These include hereditary spherocytosis, hereditary elliptocytosis, hereditary pyropoikilocytosis, and the hereditary stomatocytosis syndromes. The erythrocyte membrane skeleton composed of spectrin, actin, and several other proteins is essential for the maintenance of the erythrocyte shape, reversible deformability, and membrane structural integrity in addition to controlling the lateral mobility of integral membrane proteins. These disorders are characterized by clinical and laboratory heterogeneity and, as evidenced by recent molecular studies, by genetic heterogeneity. Defects in various proteins involved in linking the lipid bilayer to membrane skeleton result in loss in membrane cohesion leading to surface area loss and hereditary spherocytosis while defects in proteins involved in lateral interactions of the spectrin-based skeleton lead to decreased mechanical stability, membrane fragmentation and hereditary elliptocytosis. The disease severity is primarily dependent on the extent of membrane surface area loss. Treatment with splenectomy is curative in most patients.

Dissolution and surface area loss of platinum nanoparticles under potential cycling

2011 ◽  
Vol 662 (2) ◽  
pp. 379-383 ◽  
Author(s):  
Yu Sugawara ◽  
Amar Prasad Yadav ◽  
Atsushi Nishikata ◽  
Tooru Tsuru
Keyword(s):  
Surface Area ◽  
Platinum Nanoparticles ◽  
Potential Cycling ◽  
Area Loss

scholarly journals Straightforward Immobilization of Phosphonic Acids and Phosphoric Acid Esters on Mesoporous Silica and Their Application in an Asymmetric Aldol Reaction

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 249 ◽  
Author(s):  
Christian Weinberger ◽  
Tatjana Heckel ◽  
Patrick Schnippering ◽  
Markus Schmitz ◽  
Anpeng Guo ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Phosphoric Acid ◽  
Surface Area ◽  
Aldol Reaction ◽  
Synthesis Method ◽  
Mesoporous Silicas ◽  
Phosphonic Acids ◽  
Asymmetric Aldol ◽  
Asymmetric Aldol Reaction ◽  
Acid Esters

The combined benefits of moisture-stable phosphonic acids and mesoporous silica materials (SBA-15 and MCM-41) as large-surface-area solid supports offer new opportunities for several applications, such as catalysis or drug delivery. We present a comprehensive study of a straightforward synthesis method via direct immobilization of several phosphonic acids and phosphoric acid esters on various mesoporous silicas in a Dean–Stark apparatus with toluene as the solvent. Due to the utilization of azeotropic distillation, there was no need to dry phosphonic acids, phosphoric acid esters, solvents, or silicas prior to synthesis. In addition to modeling phosphonic acids, immobilization of the important biomolecule adenosine monophosphate (AMP) on the porous supports was also investigated. Due to the high surface area of the mesoporous silicas, a possible catalytic application based on immobilization of an organocatalyst for an asymmetric aldol reaction is discussed.

Enamel Etching for Universal Adhesives: Examination of Enamel Etching Protocols for Optimization of Bonding Effectiveness

2020 ◽  
Vol 45 (1) ◽  
pp. 80-91
Author(s):  
J Wong ◽  
A Tsujimoto ◽  
NG Fischer ◽  
AG Baruth ◽  
WW Barkmeier ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Surface Area ◽  
Adhesive Bonding ◽  
Sine Wave ◽  
Etching Time ◽  
Universal Adhesive ◽  
Staircase Method ◽  
Ground Enamel ◽  
Fatigue Durability ◽  
Universal Adhesives

SUMMARY Objective: The purpose of this study was to evaluate whether different enamel etching methods with reduced etching times would improve the bonding effectiveness of universal adhesives. Methods and Materials: Three enamel etching methods, phosphoric acid ester monomer (PPM) etching, phosphoric acid (PPA) etching, and polyalkenoic acid (PLA) etching, and three universal adhesives, G-Premio Bond (GP), Prime&Bond elect (PE), and Scotchbond Universal Adhesive (SU), were evaluated. Initial bond strengths and fatigue strengths of universal adhesives to ground enamel and ground enamel etched for less than one, five, 10, and 15 seconds using different etching methods were determined. The bonded fatigue specimens were loaded using a sine wave at a frequency of 20 Hz for 50,000 cycles or until failure occurred with a staircase method. Atomic force micrograph (AFM) observations along with measurements of surface Ra roughness and modified surface area of enamel with different etching protocols were also conducted. Results: The bond fatigue durability of universal adhesives to enamel with PPA etching from less than one to 15 seconds and PLA etching for 15 seconds was significantly higher than that to ground enamel. The bond fatigue durability to enamel with PPM etching was not increased compared with ground enamel. The surface Ra roughness and surface area obtained with AFM of enamel increased after PPA and PLA etching, and those values were significantly higher than those of ground enamel. Furthermore, surface Ra roughness and surface area with PPA etching were significantly higher than those with PLA etching. However, surface Ra roughness and surface area of enamel with PPM etching were similar to those of ground enamel regardless of etching time. Conclusion: PPA etching for less than one to 15 seconds and PLA etching for 15 seconds improve universal adhesive bonding, surface Ra roughness, and surface area of enamel. However, PPM etching is not effective, regardless of etching time, in improving bonds strengths, increasing surface roughness, and increasing surface area.

scholarly journals Surface area loss mechanisms of Pt3Co nanocatalysts in proton exchange membrane fuel cells

2017 ◽  
Vol 343 ◽  
pp. 571-579 ◽  
Author(s):  
S. Rasouli ◽  
R.A. Ortiz Godoy ◽  
Z. Yang ◽  
M. Gummalla ◽  
S.C. Ball ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Surface Area ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Area Loss ◽  
Exchange Membrane ◽  
Loss Mechanisms
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