Strain Induced Potentials on a 'Dirty' Polycrystalline Surface

1974 ◽  
Vol 52 (8) ◽  
pp. 708-713 ◽  
Author(s):  
Eric Enga
Keyword(s):  
Experimental Evidence ◽  
Metal Surface ◽  
Contact Potential ◽  
Strain Dependence ◽  
Produce Strain

General considerations are given as to the nature of five mechanisms which can produce strain induced potentials on a metal surface. Some experimental evidence is included. This is of interest in the question of the strain dependence of contact potential, and may be of interest in the metallurgy of surfaces.

Coupling Shift and Hydrogen Overvoltage In the Protection of Steel by Tin

CORROSION ◽  
1961 ◽  
Vol 17 (2) ◽  
pp. 93t-98t ◽  
Author(s):  
E. L. KOEHLER
Keyword(s):  
Corrosion Rate ◽  
Experimental Evidence ◽  
Hydrogen Evolution ◽  
Metal Surface ◽  
Corrosion Potential ◽  
Weak Acid ◽  
Automatic Equipment ◽  
Acid Media ◽  
Hydrogen Overvoltage ◽  
Hydrogen Reactions

Abstract Evidence is presented to further substantiate the existence of a “coupling shift” for the tin-steel couple in weak acid media. By virtue of the shift, tin is able to sacrificially protect steel concurrent with a greatly diminished rate of hydrogen evolution. Since an explanation of the phenomenon does not seem possible on the basis of existing corrosion theory, additional experimental evidence was sought to elucidate the mechanism. Polarization curves were determined with automatic equipment, enabling this to be done more rapidly and reproducibly than is usually possible. Results indicate a mechanism in which corrosion rate and corrosion potential are determined entirely on the basis of hydrogen reactions occurring on the metal surface. Coupling shift is associated with an increased hydrogen over-voltage. 5.2.1, 3.6.8

How do memory modules differentially contribute to familiarity and recollection?

2019 ◽  
Vol 42 ◽  
Author(s):  
Olya Hakobyan ◽  
Sen Cheng
Keyword(s):  
Recognition Memory ◽  
Experimental Evidence ◽  
Subjective Experience ◽  
Target Article ◽  
Memory Modules ◽  
Familiarity And Recollection ◽  
Memory Contents

Abstract We fully support dissociating the subjective experience from the memory contents in recognition memory, as Bastin et al. posit in the target article. However, having two generic memory modules with qualitatively different functions is not mandatory and is in fact inconsistent with experimental evidence. We propose that quantitative differences in the properties of the memory modules can account for the apparent dissociation of recollection and familiarity along anatomical lines.

Redox Reactions in Lipid Membranes as a Model for Primordial Energy-Conserving Systems

1997 ◽  
Vol 161 ◽  
pp. 437-442
Author(s):  
Salvatore Di Bernardo ◽  
Romana Fato ◽  
Giorgio Lenaz
Keyword(s):  
Experimental Evidence ◽  
Lipid Membranes ◽  
Energy Supply ◽  
Redox Reactions ◽  
Living Systems ◽  
Asymmetric Distribution ◽  
Conservation Of Energy ◽  
Asymmetrical Distribution ◽  
Energy Conserving ◽  
Living Organisms

AbstractOne of the peculiar aspects of living systems is the production and conservation of energy. This aspect is provided by specialized organelles, such as the mitochondria and chloroplasts, in developed living organisms. In primordial systems lacking specialized enzymatic complexes the energy supply was probably bound to the generation and maintenance of an asymmetric distribution of charged molecules in compartmentalized systems. On the basis of experimental evidence, we suggest that lipophilic quinones were involved in the generation of this asymmetrical distribution of charges through vectorial redox reactions across lipid membranes.

Electrochemical nucleation and growth of copper on iron and aluminum: A TEM study of industrial copper cementation

1978 ◽  
Vol 36 (1) ◽  
pp. 454-455
Author(s):  
L.E. Murr ◽  
V. Annamalai
Keyword(s):  
Metal Surface ◽  
Copper Deposit ◽  
Nucleation And Growth ◽  
16Th Century ◽  
Electrochemical Reactions ◽  
Mine Shaft ◽  
De Re ◽  
Copper Precipitation ◽  
Electrochemical Nucleation ◽  
Interesting System

Georgius Agricola in 1556 in his classical book, “De Re Metallica”, mentioned a strange water drawn from a mine shaft near Schmölnitz in Hungary that eroded iron and turned it into copper. This precipitation (or cementation) of copper on iron was employed as a commercial technique for producing copper at the Rio Tinto Mines in Spain in the 16th Century, and it continues today to account for as much as 15 percent of the copper produced by several U.S. copper companies.In addition to the Cu/Fe system, many other similar heterogeneous, electrochemical reactions can occur where ions from solution are reduced to metal on a more electropositive metal surface. In the case of copper precipitation from solution, aluminum is also an interesting system because of economic, environmental (ecological) and energy considerations. In studies of copper cementation on aluminum as an alternative to the historical Cu/Fe system, it was noticed that the two systems (Cu/Fe and Cu/Al) were kinetically very different, and that this difference was due in large part to differences in the structure of the residual, cement-copper deposit.

A Method for Setting the Clearance Angle

1972 ◽  
Vol 30 ◽  
pp. 388-389
Author(s):  
Michael T. Bucek ◽  
Howard J. Arnott
Keyword(s):  
Experimental Evidence ◽  
Light Source ◽  
Black Spot ◽  
Critical Factor ◽  
Clearance Angle ◽  
Crude Approximation ◽  
Ultrathin Sections

It is believed by the authors, with supporting experimental evidence, that as little as 0.5°, or less, knife clearance angle may be a critical factor in obtaining optimum quality ultrathin sections. The degree increments located on the knife holder provides the investigator with only a crude approximation of the angle at which the holder is set. With the increments displayed on the holder one cannot set the clearance angle precisely and reproducibly. The ability to routinely set this angle precisely and without difficulty would obviously be of great assistance to the operator. A device has been contrived to aid the investigator in precisely setting the clearance angle. This device is relatively simple and is easily constructed. It consists of a light source and an optically flat, front surfaced mirror with a minute black spot in the center. The mirror is affixed to the knife by placing it permanently on top of the knife holder.

Rapid Freezing of Freeze-Etch Specimens

1980 ◽  
Vol 38 ◽  
pp. 752-755
Author(s):  
A. Elgsaeter ◽  
T. Espevik ◽  
G. Kopstad
Keyword(s):  
Low Temperature ◽  
Metal Surface ◽  
Relative Velocity ◽  
Thermal Contact ◽  
High Rate ◽  
Rapid Freezing ◽  
Temperature Decrease ◽  
Freeze Etching

The importance of a high rate of temperature decrease (“rapid freezing”) when freezing specimens for freeze-etching has long been recognized1. The two basic methods for achieving rapid freezing are: 1) dropping the specimen onto a metal surface at low temperature, 2) bringing the specimen instantaneously into thermal contact with a liquid at low temperature and subsequently maintaining a high relative velocity between the liquid and the specimen. Over the last couple of years the first method has received strong renewed interest, particularily as the result of a series of important studies by Heuser and coworkers 2,3. In this paper we will compare these two freezing methods theoretically and experimentally.

Introductory Remarks

1980 ◽  
Vol 38 ◽  
pp. 598-599
Author(s):  
H. Mohri
Keyword(s):  
Muscle Contraction ◽  
Experimental Evidence ◽  
Sea Urchin ◽  
Constant Length ◽  
Thin Filaments ◽  
Bridge Formation ◽  
Thick Filaments ◽  
Sliding Mechanism ◽  
Radial Spokes ◽  
Cilia And Flagella

In 1959, Afzelius observed the presence of two rows of arms projecting from each outer doublet microtubule of the so-called 9 + 2 pattern of cilia and flagella, and suggested a possibility that the outer doublet microtubules slide with respect to each other with the aid of these arms during ciliary and flagellar movement. The identification of the arms as an ATPase, dynein, by Gibbons (1963)strengthened this hypothesis, since the ATPase-bearing heads of myosin molecules projecting from the thick filaments pull the thin filaments by cross-bridge formation during muscle contraction. The first experimental evidence for the sliding mechanism in cilia and flagella was obtained by examining the tip patterns of molluscan gill cilia by Satir (1965) who observed constant length of the microtubules during ciliary bending. Further evidence for the sliding-tubule mechanism was given by Summers and Gibbons (1971), using trypsin-treated axonemal fragments of sea urchin spermatozoa. Upon the addition of ATP, the outer doublets telescoped out from these fragments and the total length reached up to seven or more times that of the original fragment. Thus, the arms on a certain doublet microtubule can walk along the adjacent doublet when the doublet microtubules are disconnected by digestion of the interdoublet links which connect them with each other, or the radial spokes which connect them with the central pair-central sheath complex as illustrated in Fig. 1. On the basis of these pioneer works, the sliding-tubule mechanism has been established as one of the basic mechanisms for ciliary and flagellar movement.

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