Argon and nitrogen adsorption on graphite at high temperatures

1991 ◽  
Vol 56 (3) ◽  
pp. 569-579
Author(s):  
Eduardo Jorge Bottani ◽  
Jorge Luis Llanos ◽  
Lydia Ethel Cascarini de Torre
Keyword(s):  
Critical Temperature ◽  
Adsorption Isotherm ◽  
High Temperatures ◽  
Nitrogen Adsorption ◽  
Two Dimensional ◽  
Adsorbed Film ◽  
Adsorbed Phase ◽  
Wide Range ◽  
Argon Adsorption ◽  
The Hill

Nitrogen and argon adsorption on two graphites differing in their surface homogeneity was studied in a wide range of temperatures (77.5 K up to 183.2 K). The experimentally determined entropy of the adsorbed phase and isoteric heat of adsorption were analyzed. The Hill-de Boer adsorption isotherm was employed to calculate the apparent two-dimensional critical temperature. The behaviour of the adsorbed film was analyzed to explain the influence exerted upon it by temperature and surface homogenity.

scholarly journals Numerical Analysis of the Horvath–Kawazoe Equation — The Adsorption of Nitrogen, Argon, Benzene, Carbon Tetrachloride and Sulphur Hexafluoride

2002 ◽  
Vol 20 (3) ◽  
pp. 295-305 ◽  
Author(s):  
Piotr Kowalczyk ◽  
Artur P. Terzyk ◽  
Piotr A. Gauden ◽  
Gerhard Rychlicki
Keyword(s):  
Carbon Tetrachloride ◽  
Adsorption Isotherm ◽  
Numerical Procedure ◽  
Nitrogen Adsorption ◽  
Structural Parameter ◽  
Sulphur Hexafluoride ◽  
Numerical Studies ◽  
Micropore Filling ◽  
Adsorption Of Nitrogen ◽  
Argon Adsorption

A previously proposed numerical procedure based on the Horvath–Kawazoe (HK) model for estimating the MPSD (micropore size distribution) from a single nitrogen adsorption isotherm was developed. The results of the calculation of MSPD for two synthetic carbons obtained from numerical studies using the modified procedure are presented and discussed. These allowed the evaluation of the distribution from a single adsorption isotherm of nitrogen, argon, benzene, carbon tetrachloride and sulphur hexafluoride. In addition, the nitrogen and argon adsorption potential distributions were calculated for the same carbons applying the HK and condensation approximation (CA) methods. Agreement between these two independent approaches was observed. Differences between the MSPD obtained from HK and from the Dubinin micropore filling model (using the CONTIN package) were observed and discussed. It was shown that the structural parameter of the Dubinin–Astakov equation had no significant influence on the MSPD curves obtained.

Aromatic Volatile Composition of Celery and Celeriac Cultivars

HortScience ◽  
1990 ◽  
Vol 25 (5) ◽  
pp. 556-559 ◽  
Author(s):  
Fredy Van Wassenhove ◽  
Patrick Dirinck ◽  
Georges Vulsteke ◽  
Niceas Schamp
Keyword(s):  
Volatile Compounds ◽  
Chromatographic Method ◽  
Apium Graveolens ◽  
Volatile Components ◽  
Two Dimensional ◽  
Qualitative Composition ◽  
Volatile Composition ◽  
Wide Range ◽  
Gas Chromatographic Method ◽  
Identification And Quantification

A two-dimensional capillary gas chromatographic method was developed to separate and quantify aromatic volatiles of celery in one analysis. The isolation, identification, and quantification of the volatile compounds of four cultivars of blanching celery (Apium graveolens L. var. dulce) and six cultivars of celeriac (Apium graveolens L. var. rapaceum) are described. The qualitative composition of Likens-Nickerson extracts of both cultivars is similar. The concentration of terpenes and phthalides, the key volatile components, found in various cultivars of both celery and celeriac varied over a wide range.

The Cities on the Hill

2018 ◽  
Author(s):  
Thomas K. Ogorzalek
Keyword(s):  
Civil Rights ◽  
Democratic Party ◽  
Political Order ◽  
Social Difference ◽  
National Politics ◽  
Wide Range ◽  
Invaluable Tool ◽  
Urban Rural ◽  
The Hill ◽  
The New Deal

Recent electoral cycles have drawn attention to an urban–rural divide at the heart of American politics. This book traces the origins of red and blue America. The urbanicity divide began with the creation of an urban political order that united leaders from major cities and changed the Democratic Party during the New Deal era. These cities, despite being the site of serious, complex conflicts at home, are remarkably cohesive in national politics because members of city delegations represent their city as well as their district. Even though their constituents often don’t see eye-to-eye on important issues, members of these city delegations represent a united city position known as progressive liberalism. Using a wide range of congressional evidence and a unique dataset measuring the urbanicity of U.S. House districts over time, this book argues that city cohesion, an invaluable tool used by cities to address their urgent governance needs through higher levels of government, is fostered by local institutions developed to provide local political order. Crucially, these integrative institutions also helped foster the development of civil rights liberalism by linking constituencies that were not natural allies in support of group pluralism and racial equality. This in turn led to the departure from the coalition of the Southern Democrats, and to our contemporary political environment. The urban combination of diversity and liberalism—supported by institutions that make allies out of rivals—teaches us lessons for governing in a world increasingly characterized by deep social difference and political fragmentation.

Two dimensional CrGa2Se4: A spin-gapless ferromagnetic semiconductor with inclined uniaxial anisotropy

Nanoscale ◽  
2021 ◽  
Author(s):  
Qian Chen ◽  
Ruqian Wang ◽  
Zhaocong Huang ◽  
Shijun Yuan ◽  
Haowei Wang ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Material Science ◽  
2D Materials ◽  
Uniaxial Anisotropy ◽  
Magnetic Semiconductor ◽  
Ferromagnetic Semiconductor ◽  
Two Dimensional ◽  
High Critical Temperature

The magnetic semiconductor with high critical temperature has long been the focus in material science and recently is also known as one of the fundamental questions in two-dimensional (2D) materials....

scholarly journals Prediction of Wide Range Two-Dimensional Refractivity Using an IDW Interpolation Method from High-Altitude Refractivity Data of Multiple Meteorological Observatories

2021 ◽  
Vol 11 (4) ◽  
pp. 1431
Author(s):  
Sungsik Wang ◽  
Tae Heung Lim ◽  
Kyoungsoo Oh ◽  
Chulhun Seo ◽  
Hosung Choo
Keyword(s):  
High Altitude ◽  
Korean Peninsula ◽  
Interpolation Method ◽  
Atmospheric Condition ◽  
Propagation Path ◽  
Two Dimensional ◽  
Data Set ◽  
Wide Range ◽  
Atmospheric Data ◽  
Terrain Surface

This article proposes a method for the prediction of wide range two-dimensional refractivity for synthetic aperture radar (SAR) applications, using an inverse distance weighted (IDW) interpolation of high-altitude radio refractivity data from multiple meteorological observatories. The radio refractivity is extracted from an atmospheric data set of twenty meteorological observatories around the Korean Peninsula along a given altitude. Then, from the sparse refractive data, the two-dimensional regional radio refractivity of the entire Korean Peninsula is derived using the IDW interpolation, in consideration of the curvature of the Earth. The refractivities of the four seasons in 2019 are derived at the locations of seven meteorological observatories within the Korean Peninsula, using the refractivity data from the other nineteen observatories. The atmospheric refractivities on 15 February 2019 are then evaluated across the entire Korean Peninsula, using the atmospheric data collected from the twenty meteorological observatories. We found that the proposed IDW interpolation has the lowest average, the lowest average root-mean-square error (RMSE) of ∇M (gradient of M), and more continuous results than other methods. To compare the resulting IDW refractivity interpolation for airborne SAR applications, all the propagation path losses across Pohang and Heuksando are obtained using the standard atmospheric condition of ∇M = 118 and the observation-based interpolated atmospheric conditions on 15 February 2019. On the terrain surface ranging from 90 km to 190 km, the average path losses in the standard and derived conditions are 179.7 dB and 182.1 dB, respectively. Finally, based on the air-to-ground scenario in the SAR application, two-dimensional illuminated field intensities on the terrain surface are illustrated.

scholarly journals Threshold selection in univariate extreme value analysis

Extremes ◽  
2021 ◽  
Author(s):  
Laura Fee Schneider ◽  
Andrea Krajina ◽  
Tatyana Krivobokova
Keyword(s):  
Mean Squared Error ◽  
Extreme Value ◽  
Hill Estimator ◽  
Small Samples ◽  
Extreme Value Analysis ◽  
Threshold Selection ◽  
Value Analysis ◽  
Wide Range ◽  
Asymptotic Mean Squared Error ◽  
The Hill

AbstractThreshold selection plays a key role in various aspects of statistical inference of rare events. In this work, two new threshold selection methods are introduced. The first approach measures the fit of the exponential approximation above a threshold and achieves good performance in small samples. The second method smoothly estimates the asymptotic mean squared error of the Hill estimator and performs consistently well over a wide range of processes. Both methods are analyzed theoretically, compared to existing procedures in an extensive simulation study and applied to a dataset of financial losses, where the underlying extreme value index is assumed to vary over time.

scholarly journals Is contact angle a cause or an effect? – A cautionary tale

2020 ◽  
Vol 146 ◽  
pp. 03004
Author(s):  
Douglas Ruth
Keyword(s):  
Contact Angle ◽  
Solid Surface ◽  
Contact Angles ◽  
Two Dimensions ◽  
Experimental Results ◽  
Flow In Porous Media ◽  
Two Dimensional ◽  
Wide Range ◽  
Fluid Drop ◽  
Surrounding Fluid

The most influential parameter on the behavior of two-component flow in porous media is “wettability”. When wettability is being characterized, the most frequently used parameter is the “contact angle”. When a fluid-drop is placed on a solid surface, in the presence of a second, surrounding fluid, the fluid-fluid surface contacts the solid-surface at an angle that is typically measured through the fluid-drop. If this angle is less than 90°, the fluid in the drop is said to “wet” the surface. If this angle is greater than 90°, the surrounding fluid is said to “wet” the surface. This definition is universally accepted and appears to be scientifically justifiable, at least for a static situation where the solid surface is horizontal. Recently, this concept has been extended to characterize wettability in non-static situations using high-resolution, two-dimensional digital images of multi-component systems. Using simple thought experiments and published experimental results, many of them decades old, it will be demonstrated that contact angles are not primary parameters – their values depend on many other parameters. Using these arguments, it will be demonstrated that contact angles are not the cause of wettability behavior but the effect of wettability behavior and other parameters. The result of this is that the contact angle cannot be used as a primary indicator of wettability except in very restricted situations. Furthermore, it will be demonstrated that even for the simple case of a capillary interface in a vertical tube, attempting to use simply a two-dimensional image to determine the contact angle can result in a wide range of measured values. This observation is consistent with some published experimental results. It follows that contact angles measured in two-dimensions cannot be trusted to provide accurate values and these values should not be used to characterize the wettability of the system.

scholarly journals Recovery of long-range order in two-dimensional charge density waves at high temperatures

2021 ◽  
Vol 27 (S1) ◽  
pp. 952-954
Author(s):  
Suk Hyun Sung ◽  
Yin Min Goh ◽  
Noah Schnitzer ◽  
Ismail El Baggari ◽  
Kai Sun ◽  
...  
Keyword(s):  
Charge Density ◽  
Long Range ◽  
High Temperatures ◽  
Charge Density Waves ◽  
Range Order ◽  
Long Range Order ◽  
Two Dimensional ◽  
Density Waves

scholarly journals Robust anomalous metallic states and vestiges of self-duality in two-dimensional granular In-InOx composites

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Xinyang Zhang ◽  
Bar Hen ◽  
Alexander Palevski ◽  
Aharon Kapitulnik
Keyword(s):  
Magnetic Field ◽  
Metallic Phase ◽  
Broadband Noise ◽  
Two Dimensional ◽  
Conventional Theory ◽  
Logarithmic Divergence ◽  
Self Duality ◽  
Low Field ◽  
Wide Range ◽  
Low Temperature Resistance

AbstractMany experiments investigating magnetic-field tuned superconductor-insulator transition (H-SIT) often exhibit low-temperature resistance saturation, which is interpreted as an anomalous metallic phase emerging from a ‘failed superconductor’, thus challenging conventional theory. Here we study a random granular array of indium islands grown on a gateable layer of indium-oxide. By tuning the intergrain couplings, we reveal a wide range of magnetic fields where resistance saturation is observed, under conditions of careful electromagnetic filtering and within a wide range of linear response. Exposure to external broadband noise or microwave radiation is shown to strengthen the tendency of superconductivity, where at low field a global superconducting phase is restored. Increasing magnetic field unveils an ‘avoided H-SIT’ that exhibits granularity-induced logarithmic divergence of the resistance/conductance above/below that transition, pointing to possible vestiges of the original emergent duality observed in a true H-SIT. We conclude that anomalous metallic phase is intimately associated with inherent inhomogeneities, exhibiting robust behavior at attainable temperatures for strongly granular two-dimensional systems.

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