scholarly journals An Overview of Common Infrared Techniques for Detecting CO Intermediates on Metal Surfaces for Hydrocarbon Products

Physchem ◽  
2022 ◽  
Vol 2 (1) ◽  
pp. 1-15
Author(s):  
Ahmed M. El-Zohry
Keyword(s):  
Metal Surfaces ◽  
The Other ◽  
Catalytic Process ◽  
Transient Species ◽  
Reduction Of Co2 ◽  
Vibrational Features ◽  
Infrared Techniques

Detection of intermediates during the catalytic process by infrared techniques has been widely implemented for many important reactions. For the reduction of CO2 into hydrocarbons on metal surfaces, CO molecule is one of the most important transient species to be followed due to its involvement in several products’ pathways, and its distinct vibrational features. Herein, basic understandings behind these utilized infrared techniques are illustrated aiming for highlighting the potential of each infrared technique and its advantages over the other ones for detecting CO molecules on metal surfaces.

Little epigraphy

Lampas ◽  
2021 ◽  
Vol 54 (1) ◽  
pp. 119-136
Author(s):  
Robert Pitt
Keyword(s):  
Metal Surfaces ◽  
The Other ◽  
Content Type ◽  
Weights And Measures ◽  
Other Hand ◽  
Large Corpus

Abstract Most well-known inscriptions are monumental texts carved on stone. In this contribution, on the other hand, we focus on small, often informal texts scratched or stamped on rocks, metal surfaces and pottery. To this type of so-called ‘little epigraphy’ belong for instance graffiti, ostraca, weights and measures, curse tablets, etcetera. Although the texts themselves are usually very short, together they constitute a large corpus.

Decreasing the Adhesion Effect of Surfaces Using Graphite Pellicle Deposition through Electric Discharges in Pulse

2014 ◽  
Vol 1036 ◽  
pp. 172-177 ◽  
Author(s):  
Pavel Topala ◽  
Vitalie Besliu ◽  
Laurentiu Marin
Keyword(s):  
Experimental Research ◽  
Metal Surfaces ◽  
The Other ◽  
Electric Discharges ◽  
Polyurethane Adhesive ◽  
Test Pieces ◽  
Other Hand ◽  
The One ◽  
Adhesion Effect

The paper aims at studying the phenomenon of adhesion between the graphite pellicles deposited through electric discharges in pulse (EDI) with metal surfaces subjected to processing on the one hand and on the other hand the adhesion of this pellicle with a polyurethane adhesive. Experimental research has shown that, when the surfaces are not treated, the shear occurs in the adhesive, when the test pieces are covered with graphite pellicles the shear occurs on the surface that separates the pellicle from the adhesive. It has been stated experimentally that graphite pellicles deposited through electric discharges in pulse decrease the adhesion between the mating surfaces by at least 40% compared to the not treated surfaces.

Chemical Restructuring of Metal Surfaces Studied by Scanning Tunneling Microscope (STM)

1997 ◽  
Vol 3 (S2) ◽  
pp. 577-578
Author(s):  
Ken-ichi Tanaka
Keyword(s):  
Scanning Tunneling Microscope ◽  
Metal Surfaces ◽  
Substrate Surface ◽  
Critical Value ◽  
Dissociative Adsorption ◽  
The Other ◽  
Scanning Tunneling ◽  
Tunneling Microscope ◽  
Oxygen Coverage ◽  
Nano Size

Metal surfaces undergo structural change by the dissociative adsorption of O2, where the reconstructuring is caused by either of the two distinctive mechanisms depending on the temperature and/or the crystalographic planes, one is the “adsorption induced reconstruction” and the other is the “formation of quasi-compounds and their array over the surface”.The oxygen induced reconstruction of Cu(100) is the former case. When a Cu(100) surface is exposed to O2, oxygen atoms are adsored by making nano-size c(2x2) structure to avoid the convergence of the stress induced by the adsorption. When the oxygen coverage exceeds a critical value of ca 0.3 ML, Cu atoms are missed from the substrate surface to release the stress and the R45 reconstruction is established. In contrast to the Cu(l00) surface, an entirely different process takes place on a Cu( 110) surface exposed to O2, where the (-Cu-O-) string is formed and by a chemical array over the terrace occur.

Fabrication and Corrosion Performance of a Superhydrophobic Stainless Steel Surface

2019 ◽  
Author(s):  
Mona Amiriafshar ◽  
Xili Duan ◽  
Ali Nasiri
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Metal Surfaces ◽  
Ground Surface ◽  
The Other ◽  
Polished Surface ◽  
Corrosion Performance ◽  
Micro Scale ◽  
Steel Surfaces ◽  
Entrapped Air

Abstract Fabrication of surfaces with hydrophobic and superhydrophobic property has drawn extensive interests as a solution to protect metal surfaces from corrosion attacks, with potential applications in cooling devices for electronics, microfluidic systems for controlled drug delivery, as well as anti-icing, and self-cleaning techniques. This study addresses the impact of surface wettability, i.e., hydrophobicity and superhydrophobicity, on corrosion resistance improvement of metal materials. Hydrophobic and superhydrophobic metal surfaces are desirable to minimize the adhesion between water droplets and the surface. This study aims to fabricate and investigate 17-4 PH stainless steel surfaces with lowered surface energies and modified wetting properties. Various micro- and sub-micro scale finished surfaces with different surface roughness, namely as-received, sandblasted, ground, and polished, were employed, followed by applying a low energy superhydrophobic coating to fabricate hydrophobic and superhydrophobic surfaces on 17-4 PH stainless steel base material. The specific impacts of the surface roughness on wettability and corrosion resistivity of the manufactured surfaces were examined. The ground and polished surfaces followed by applying a 30–50 μm thick superhydrophobic dip coating resulted in steady-state contact angles of up to 152° and 146°, respectively, while the non-engineered coated base metal exhibited the contact angle of 140°. The ground surface with the average surface roughness (Ra) of ∼ 0.03 μm has the optimal roughness. According to the Cassie-Baxter model, the coated ground surface can retain the entrapped air within its interstices more adequately than the other surfaces with either lower surface roughness, such as the polished surface with the roughness of 0.02 μm, or higher surface roughness, such as as-received and sandblasted surfaces with the Ra value of 5.52 μm and 11.98 μm, respectively. To study the corrosion performance and electrochemical stability of the fabricated surfaces, cyclic polarization testing (CPT) and electrochemical impedance spectroscopy (EIS) were performed in an aerated 3.5 wt.% NaCl solution that mimics seawater environment. The electrochemical measurements confirmed that the water-repelling property of the surface contributes to the anti-corrosion capability of the substrate. Data from the corrosion tests indicate that the lowest corrosion current density, highest corrosion potential, and highest pitting potential, were found for the coated ground surface followed by the coated polished surface. The EIS results also highlighted the significantly greater absolute value of impedance for the coated ground and coated polished surfaces even after 240 hrs of immersion in the electrolyte solution than the other fabricated surfaces at lower frequency ranges. The improvement in the 17-4 PH stainless steel corrosion performance was contributed to the size of the fabricated surface micro- and sub-micro scale features, capable of retaining the entrapped air within the roughened surface structure when fully immersed in a corrosive environment. This work demonstrates the effectiveness of a simple fabrication process to create hydrophobic and superhydrophobic stainless steel surfaces with improved corrosion resistivity.

scholarly journals IV. On the passage of heat between metal surfaces and liquids in contact with them

1897 ◽  
Vol 190 ◽  
pp. 67-88 ◽  
Keyword(s):  
Thermal Resistance ◽  
Metal Surfaces ◽  
Metal Plate ◽  
Hot Water ◽  
The Other ◽  
The Subject ◽  
Heated Metal ◽  
Thermal Conductivities

The determination of the rate of transmission of heat from the surface of a heated metal to water in contact with it, or from hot water to a colder surface, is a problem of some difficulty, but is of such great importance in the theory of boilers and surface condensers, that further investigation would seem to be justified, especially as, although the theory of the subject has been much studied, yet owing to practical difficulties, the constants involved, so far as the author is aware, have not been definitely determined for cases which occur in practice. Peclet’s experiments on the rate of transmission of heat from water to water across a metal plate, throw much light on the question. His experiments were made to determine the thermal conductivities of various metals by measuring the heat passed through a metal plate, one side of which was exposed to steam and the other to water which was kept agitated by a stirrer. In these experiments, Peclet found that the heat transmitted was sensibly independent of the nature and thickness of the metal used, the conclusion being that on each side of the plate there was a film of water through which the heat was transmitted by conduction, and that compared to these, the thermal resistance of the plate was small. This difficulty was overcome by an arrangement consisting of revolving brushes in contact with each side of the plate, so as to prevent the formation of a film on the surfaces, and by keeping the water in a violent state of agitation. In this way it was possible to keep the surfaces of the plate at the same temperature as the water in contact with them, and the conductivities of metals determined by this method agree with carefully determined conductivities obtained by other methods.

On the Mechanism of Contact Between Metal Surfaces—The Penetrating Depth and the Average Clearance

1965 ◽  
Vol 87 (3) ◽  
pp. 666-672 ◽  
Author(s):  
Tadasu Tsukizoe ◽  
Terumasa Hisakado
Keyword(s):  
Metal Surfaces ◽  
Applied Load ◽  
Distribution Curve ◽  
The Other ◽  
Real Contact Area ◽  
Profile Curve ◽  
Air Leakage ◽  
Real Contact ◽  
The One ◽  
Good Agreement

The analysis of the mechanism of air leakage through the interstices between metal surfaces in contact or of the mechanism of thermal resistance between them is dependent on the average clearance between opposite surfaces or on the distribution of the real contact area; i.e., the mechanism of contact. Assuming that the distribution curve obtained from the profile curve of the surface has a normal distribution, the relation between the applied load and the average clearance or the penetrating depth, i.e., the distance through which the one surface moves into the other surface, is obtained theoretically. A comparison of calculated values based on this theory with experimental data shows good agreement.

scholarly journals Molybdenum(V) e.p.r. signals obtained from xanthine oxidase on reduction with aldehyde substrates and with 2-amino-4-hydroxy-6-formylpteridine

1981 ◽  
Vol 197 (2) ◽  
pp. 421-425 ◽  
Author(s):  
J P Malthouse ◽  
J W Williams ◽  
R C Bray
Keyword(s):  
Xanthine Oxidase ◽  
Computer Simulations ◽  
Side Reaction ◽  
The Other ◽  
Catalytic Process ◽  
Active Centre ◽  
Other Hand

2-Amino-4-hydroxy-6-formylpteridine, a known ‘slow’ substrate and inhibitor of xanthine oxidase, is unusual in that it gives rise under suitable conditions to all types of molybdenum(V) e.p.r. signals obtainable from the enzyme, namely Very Rapid, Rapid, Inhibited and Slow. The Very Rapid signal appears in a slightly modified form. The Inhibited signal, originally thought to be unique to reaction of methanol or of formaldehyde with xanthine oxidase, is now shown to be obtainable with several other aldehydes. These include, in addition to 2-amino-4-hydroxy-6-formylpteridine, acetaldehyde and glycoaldehyde. Parameters of the signals, obtained with the help of computer simulations, are presented. The appearance of Very Rapid and of Inhibited signals with these additional substrates may be of importance in elucidating the structure of the enzyme active centre. In agreement with previous work, the Very Rapid signal is attributed to an obligatory intermediate in turnover. On the other hand, the Inhibited signal is attributed to a side reaction, presumably inhibitory in nature, occurring during the catalytic process.

Stromatoporoids from the Famennian (Devonian) Wabamun Formation, Normandville oilfield, north–central Alberta, Canada

1988 ◽  
Vol 62 (03) ◽  
pp. 411-419 ◽  
Author(s):  
Colin W. Stearn
Keyword(s):  
Patch Reef ◽  
Abundant Species ◽  
The Other ◽  
North Central ◽  
Biotic Crisis

Stromatoporoids are the principal framebuilding organisms in the patch reef that is part of the reservoir of the Normandville field. The reef is 10 m thick and 1.5 km2in area and demonstrates that stromatoporoids retained their ability to build reefal edifices into Famennian time despite the biotic crisis at the close of Frasnian time. The fauna is dominated by labechiids but includes three non-labechiid species. The most abundant species isStylostroma sinense(Dong) butLabechia palliseriStearn is also common. Both these species are highly variable and are described in terms of multiple phases that occur in a single skeleton. The other species described areClathrostromacf.C. jukkenseYavorsky,Gerronostromasp. (a columnar species), andStromatoporasp. The fauna belongs in Famennian/Strunian assemblage 2 as defined by Stearn et al. (1988).

D. The Line Spectrum of Pulsating Variable Stars

1967 ◽  
Vol 28 ◽  
pp. 207-244
Author(s):  
R. P. Kraft
Keyword(s):  
Variable Stars ◽  
The Other ◽  
Line Spectrum ◽  
Afternoon Session ◽  
Empirical Information ◽  
Pulsating Variable Stars ◽  
Almost Continuous ◽  
Informal Approach

(Ed. note:Encouraged by the success of the more informal approach in Christy's presentation, we tried an even more extreme experiment in this session, I-D. In essence, Kraft held the floor continuously all morning, and for the hour and a half afternoon session, serving as a combined Summary-Introductory speaker and a marathon-moderator of a running discussion on the line spectrum of cepheids. There was almost continuous interruption of his presentation; and most points raised from the floor were followed through in detail, no matter how digressive to the main presentation. This approach turned out to be much too extreme. It is wearing on the speaker, and the other members of the symposium feel more like an audience and less like participants in a dissective discussion. Because Kraft presented a compendious collection of empirical information, and, based on it, an exceedingly novel series of suggestions on the cepheid problem, these defects were probably aggravated by the first and alleviated by the second. I am much indebted to Kraft for working with me on a preliminary editing, to try to delete the side-excursions and to retain coherence about the main points. As usual, however, all responsibility for defects in final editing is wholly my own.)

C. The Continuous Spectrum of Pulsating Variable Stars

1967 ◽  
Vol 28 ◽  
pp. 177-206
Author(s):  
J. B. Oke ◽  
C. A. Whitney
Keyword(s):  
Continuous Spectrum ◽  
Variable Stars ◽  
Velocity Fields ◽  
The Other ◽  
Line Spectrum ◽  
Direct Information ◽  
Thermodynamic Structure ◽  
Diagnostic Interpretation ◽  
Pulsating Variable Stars ◽  
The Continuum

Pecker:The topic to be considered today is the continuous spectrum of certain stars, whose variability we attribute to a pulsation of some part of their structure. Obviously, this continuous spectrum provides a test of the pulsation theory to the extent that the continuum is completely and accurately observed and that we can analyse it to infer the structure of the star producing it. The continuum is one of the two possible spectral observations; the other is the line spectrum. It is obvious that from studies of the continuum alone, we obtain no direct information on the velocity fields in the star. We obtain information only on the thermodynamic structure of the photospheric layers of these stars–the photospheric layers being defined as those from which the observed continuum directly arises. So the problems arising in a study of the continuum are of two general kinds: completeness of observation, and adequacy of diagnostic interpretation. I will make a few comments on these, then turn the meeting over to Oke and Whitney.

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