scholarly journals Self-consistent dielectric functions of materials: Toward accurate computation of Casimir–van der Waals forces

2021 ◽  
Vol 7 (22) ◽  
pp. eabg2272
Author(s):  
Mohsen Moazzami Gudarzi ◽  
Seyed Hamed Aboutalebi
Keyword(s):  
Sum Rules ◽  
Van Der Waals ◽  
Accurate Determination ◽  
Experimental Measurements ◽  
Practical Applications ◽  
Inorganic Semiconductors ◽  
Wide Range ◽  
Self Consistent ◽  
Extensive List

Research on theoretical calculation of Casimir–van der Waals (vdW) forces is characterized by a great number of inconsistencies and conflicting reports with widely differing results for many known materials, including water, contradicting experimental measurements. Despite its importance for conceptual advances in both fundamental aspects and practical applications, a universal framework for the accurate determination of Casimir-vdW forces is lacking. Here, we propose a universal theoretical platform for computing Casimir-vdW forces, accounting for the electronic dielectric constant, optical bandgap, density, and chemical composition. Using this methodology, we determine the dielectric function for 55 materials, over a wide range of photon energies, covering an extensive list of common metals, organic and inorganic semiconductors, and insulators. Internal consistency of the compiled data is validated using optical sum rules and Kramers-Kronig relations. We demonstrate that the calculated vdW forces based on these data match remarkably well with the experimentally measured vdW forces.

scholarly journals Highly accurate determination of heterogeneously stacked Van-der-Waals materials by optical microspectroscopy

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Andreas Hutzler ◽  
Birk Fritsch ◽  
Christian D. Matthus ◽  
Michael P. M. Jank ◽  
Mathias Rommel
Keyword(s):  
Van Der Waals ◽  
Accurate Determination ◽  
Van Der Waals Materials

scholarly journals Determining Girard Form Class in Central Hardwoods

1997 ◽  
Vol 14 (4) ◽  
pp. 202-206 ◽  
Author(s):  
John C. Rennie ◽  
Jack D. Leake
Keyword(s):  
Direct Measurement ◽  
Accurate Determination ◽  
Tree Form ◽  
Form Class ◽  
Wide Range ◽  
Close Proximity ◽  
Wedge Prism ◽  
The Cost ◽  
Volume Estimates

Abstract Girard form class is widely used to describe tree form. Tree volume estimates change about 3% per unit change of Girard form class (Mesavage and Girard 1946). Hardwoods growing in close proximity have been observed to have a wide range in Girard form class. Accurate determination of Girard form class can therefore be important in getting accurate estimates of hardwood timber volume. However, the cost of estimating Girard form class for every tree being measured in the stand would be prohibitively expensive. Thus, estimation of average Girard form class for a stand is considered here. Three instruments used to estimate Girard form class—a Wheeler pentaprism optical caliper, a wedge prism, and a Spiegel relaskop—were compared to direct measurement. Number of sample trees to achieve desired half-widths of the confidence interval of ±1 and ±1 1/2 units of Girard form class was calculated for each method. Direct measurement requires the fewest trees to achieve the desired results. However, it requires considerably more time per tree than any of the instruments tested. The Wheeler pentaprism requires only a few more trees than direct measurement, and considerably fewer trees than either the wedge prism or the Spiegel relaskop. Use of all three instruments is hindered when understory vegetation obscures the top of the first log. North. J. Appl. For. 14(4):202-206.

scholarly journals The upper limits of the continuous β-ray spectra of thorium C and C″

1934 ◽  
Vol 147 (862) ◽  
pp. 572-582 ◽  
Keyword(s):  
Accurate Determination ◽  
Simple Relation ◽  
Maximum Energy ◽  
Energy Limit ◽  
Expansion Chamber ◽  
End Point ◽  
Upper Limits ◽  
Wide Range ◽  
Magnetic Analysis

It is well known that the disintegration electrons from a radioactive body are distributed over a wide range of velocities, and that a characteristic feature of this distribution is that there is an upper energy limit above which no electrons are emitted. The accurate determination of these upper limits and the corresponding maximum energy of the β-rays has become of much importance in connection with special theories which have been advanced to explain the nature of the β-ray disintegration. Numerous experiments have been done to find these upper limits or end points. Most of the existing data are based on range measurements in which the energy of the fastest β-rays from a source is deduced from their range. The chief advantage of the method is that it can be carried out with weak or rapidly decaying sources; the great disadvantage is that owing to the scattering suffered by the β-particles, the range found by experiment is an indefinite quantity and has no simple relation to the maximum energy of the β-particles. Because of this fact range methods, while frequently giving results in general agreement with magnetic analysis, are not capable of leading to accurate results for the upper limits. There remain two other methods of analysis, the magnetic spectrograph and the expansion chamber. The latter as used by Terroux and Alexander gives a higher upper limit than other methods. For radium E Terroux reported a tail extending to 3,000,000 volts, while other methods give an end point at about 1,070,000 volts. Champion, in repeating Terroux’s experiments, emphasized the precautions that must be taken in interpreting the experimental material. To eliminate the effect of scattering he was forced to adopt a criterion that a particle would be counted only if it had an undisturbed track greater than a certain length. The cloud-chamber method, while applicable to very weak sources, must be used with great care, and cannot give an accurate value of the end point without taking a very large number of photographs.

scholarly journals CREDIT CAPACITY ASSESSMENT OF COMMERCIAL BANK BORROWER

2019 ◽  
pp. 93-100
Author(s):  
A. Bondarenko ◽  
M. Moiseienko ◽  
V. Gordienko ◽  
O. Dutchenko
Keyword(s):  
Credit Risk ◽  
Accurate Determination ◽  
Integral Model ◽  
Risk Indicator ◽  
Probability Of Default ◽  
Financial Condition ◽  
Wide Range ◽  
Banking Institution ◽  
High Level

The purpose of the article is to study the essence of solvency of the enterprise, to determine the approaches to assessment and analysis of solvency. Since the assessment of the borrower's solvency is the key to the successful functioning not only of the financial and credit institution, but also of the enterprise itself, so in the conditions of formation and development of market relations lenders need to have an accurate idea of the borrower's solvency. Relevance of the research topic is explained by the fact that today the solvency of the enterprise requires a thorough and comprehensive research in terms of the solvency of enterprises and the development of a scientific justification for a common algorithm that borrowers can use to calculate their credit obligations. Today, there is no single algorithm for determining a borrower's solvency. Each banking institution uses its own methodology, which, in its opinion, is the most effective and takes into account a wide range of financial indicators. According to the valuation specificity for the assessment of legal entities regulated by the NBU, determining the borrower's solvency involves analyzing its financial and economic characteristics Requirements of the Regulations on the determination of the size of credit risk by the banks of Ukraine established the calculation of the credit risk indicator, which provides for the definition of the integral indicator, calculation of the borrower's financial class and the probability of default. Within the limits of the given research the complex estimation of Technologia JSC solvency has been carried out, by results of which the quantitative indicators received as a result of construction of the integral model, are included into the range of values corresponding to the second class of the borrower. Calculation of the overall qualitative indicator confirmed the high level of solvency of the studied enterprise, with a minimum probability of default. In order to improve the quality of the solvency assessment of the borrower we propose, in further studies, to consider the competitiveness of the enterprise as a factor of more accurate determination of its financial condition and solvency. Keywords: solvency, borrower, financial standing, financial factors.

Relation between outer and luminal diameter in cannulated arteries

1999 ◽  
Vol 277 (5) ◽  
pp. H1745-H1753 ◽  
Author(s):  
Gilles Faury ◽  
Gail M. Maher ◽  
Dean Y. Li ◽  
Mark T. Keating ◽  
Robert P. Mecham ◽  
...  
Keyword(s):  
Accurate Determination ◽  
Experimental Conditions ◽  
Cross Sectional ◽  
Luminal Diameter ◽  
Fluorescent Marker ◽  
Wide Range ◽  
Before And After ◽  
Single Determination ◽  
Knockout Animals

Resistance in blood vessels is directly related to the inner (luminal) diameter (ID). However, ID can be difficult to measure during physiological experiments because of poor transillumination of thick-walled or tightly constricted vessels. We investigated whether the wall cross-sectional area (WCSA) in cannulated arteries is nearly constant, allowing IDs to be calculated from outer diameters (OD) using a single determination of WCSA. With the use of image analysis, OD and ID were directly measured using either transillumination or a fluorescent marker in the lumen. IDs from a variety of vessel types were calculated from WCSA at several reference pressures. Calculated IDs at all of the reference WCSA were within 5% (mean <1%) of the corresponding measured IDs in all vessel types studied, including vessels from heterozygote elastin knockout animals. This was true over a wide range of transmural pressures, during treatment with agonists, and before and after treatment with KCN. In conclusion, WCSA remains virtually constant in cannulated vessels, allowing accurate determination of ID from OD measurement under a variety of experimental conditions.

scholarly journals Accurate determination of the Fermi surface of tetragonal FeS via quantum oscillation measurements and quasiparticle self-consistent GW calculations

2019 ◽  
Vol 99 (13) ◽  
Author(s):  
Taichi Terashima ◽  
Naoki Kikugawa ◽  
David Graf ◽  
Hishiro T. Hirose ◽  
Shinya Uji ◽  
...  
Keyword(s):  
Fermi Surface ◽  
Accurate Determination ◽  
Quantum Oscillation ◽  
Self Consistent

An accurate determination of the HeAr van der Waals potential

1978 ◽  
Vol 59 (2) ◽  
pp. 339-345 ◽  
Author(s):  
Mark Keil ◽  
Aron Kuppermann ◽  
John T. Slankas
Keyword(s):  
Van Der Waals ◽  
Accurate Determination

scholarly journals A rapid and convenient technique for measuring the rate of protein synthesis in tissues by injection of [3H]phenylalanine

1980 ◽  
Vol 192 (2) ◽  
pp. 719-723 ◽  
Author(s):  
P J Garlick ◽  
M A McNurlan ◽  
V R Preedy
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Large Dose ◽  
Accurate Determination ◽  
Specific Radioactivity ◽  
Rapid Rise ◽  
Rapid Procedure ◽  
Wide Range ◽  
Convenient Technique

A rapid procedure for measuring the specific radioactivity of phenylalanine in tissues was developed. This facilitates the accurate determination of rates of protein synthesis in a wide range of tissues by injection of 150 mumol of L-[4-(3)H]phenylalanine/100 g body wt. The large dose of amino acid results in a rapid rise in specific radioactivity of free phenylalanine in tissues to values close to that in plasma, followed by a slow but linear fall. This enables the rate of protein synthesis to be calculated from measurements of the specific radioactivity of free and protein-bound phenylalanine in tissues during a 10 min period after injection of radioisotope.

MoSx–Co3O4 Nanocomposite for Selective Determination of Ascorbic Acid

2021 ◽  
Vol 21 (4) ◽  
pp. 2595-2603
Author(s):  
Sidra Amin ◽  
Aneela Tahira ◽  
Amber Solangi ◽  
Ayman Nafady ◽  
Zafar Hussain Ibupoto
Keyword(s):  
Ascorbic Acid ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Limit Of Detection ◽  
Active Surface Area ◽  
Carbon Electrode ◽  
Selective Determination ◽  
Practical Applications ◽  
Wide Range

Designing a nanocomposite with sensitive and selective determination of ascorbic acid is challenging task. It is possible through the exploitation of attractive features of nanoscience and nanotechnology for the synthesis of nanostructured materials. Herein, we report the decoration of nanoparticle of MoSx on the surface of Co3O4 nanowires by hydrothermal method. The MoSx nanoparticles shared the large surface on the Co3O4 nanowires, thus it supported in the development enzyme free ascorbic acid sensor. Non-enzymatic sensor based on MoSx-Co3O4 composite was found very selective for the determination of ascorbic acid (AA) in phosphate buffer solution of pH 7.4. The MoSx-Co3O4 nanocomposite was used to modify the glassy carbon electrode to measure AA from variety of practical samples. The MoSx-Co3O4 nanocomposite was used to modify the glassy carbon electrode and it has shown the attractive analytical features such as a low working potential +0.3 V, linear range of concentration from 100–7000 μM, low limit of detection 14 μM, and low limit of quantification (LOQ) of 42 μM. The developed sensor is highly selective and stable. Importantly, it was applied successfully for the practical applications such as detection of AA from grapefruit, tomato and lemon juice. The excellent electrochemical properties of fabricated MoSx-Co3O4 nanocomposite can be attributed to the increasing electro active surface area of MoSx. The presented nanocomposite is earth abundant, environment friendly and inexpensive and it holds promising features for the selective and sensitive determination of AA from practical applications. The nanocomposite can be capitalized into the wide range of biomedical applications.

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