scholarly journals On the measurement of the dielectric constants of liquids, with a determination of the dielectric constant of benzene

1929 ◽  
Vol 123 (792) ◽  
pp. 664-685 ◽  
Keyword(s):  
Dielectric Constant ◽  
Physical Properties ◽  
Dielectric Constants ◽  
Experimental Conditions ◽  
The Past ◽  
A Value ◽  
The Subject ◽  
Important Indication

It has long been recognised that the dielectric constant of a substance gives an important indication of its constitution, and the classical papers of Nernst and Drude giving methods for the determination of dielectric constants, have been followed by a long series of papers giving the dielectric constants of several hundreds of pure liquids and solutions. Since the publication of Debye’s dipole theory in 1912, the literature of the subject has become even more voluminous than before. In surveying the mass of data one is struck by the very large discrepancies which exist in the values obtained by different observers for any one substance, and it is very difficult to decide whether they are due to the difficulty of pre­paring and purifying the substance, differences in experimental conditions such as frequency of the applied E. M. F., or errors in the methods of measure­ment. In order to make it possible to compare the results of different observers, and to provide a fundamental basis for new measurements, it is important that the value of at least one standard liquid should be known with unquestion­able accuracy. The object of the present investigation was to provide such a value. Benzene was chosen as the standard liquid since it has been very widely used in the past, and it is used as a standard in the measurement of other physical properties.

scholarly journals The variation of the dielectric constants of some organic liquids with frequency in the range 1 to 10 3 Kilocycles

1930 ◽  
Vol 126 (801) ◽  
pp. 213-230 ◽  
Keyword(s):  
Dielectric Constant ◽  
Extreme Values ◽  
Dielectric Constants ◽  
Organic Liquids ◽  
Frequency Range ◽  
Absolute Value ◽  
The Subject ◽  
The Mean ◽  
Made In

Whilst it is recognised that the dielectric constant of liquids changes in the frequency range 10 4 - 10 5 kilocycles per second in accordance with the theory of Debye, no systematic examination of the variation of the dielectric constant of simple liquids with frequency appears to have been made at frequencies below 10 3 kc. per second. Exception must be made of the work of Fricke* who showed that the dielectric constant of blood did not change in the range 0­­­­.8 to 4500 kc., and of that of Bryan who recorded no change in the constant for xylene and an increase in the constant for nitrobenzene in the range 200 to1200 kc. In the case of chloroform and benzene a number of independent determinations have been made, eachat a fixed frequency. The values of the constants, however, at frequencies less than 1000kc. fluctuate considerably, for benzene the divergence between the extreme values is about 2­­·0 percent, of the mean, for chloroform about 12­­·5 percent. It is of importance, therefore, to establish whether these fluctuations are due to experimental error or the variation of the constant with frequency. The experiments now described were planned preliminary to work at higher frequencies; measurements of the dielectric constant and of the conductivity of a number of liquids have been made in the frequency range 1 to 10 3 kc. Attention has been directed to examine the variation of these quantities with frequency rather than to obtain­ing their absolute values. Owing to the illness of one of the authors the work had to be discontinued before the original programme had been completed, nevertheless, in view of the increasing importance of the subject the results appear to be of sufficient interest to merit publication. Since the data now reported were obtained, an extremely careful determination of the absolute value of the dielectric constant for benzene at 1000 cycles has been described by Hartshorn and Oliver ( loc. cit. ). They report no change in the constant in the audio frequency range, that is, presumably, below 5 kc., and thus confirm, in part, the data now presented.

scholarly journals A note on some further determinations of the dielectric constants of organic bodies and electrolytes at very low temperatures

1898 ◽  
Vol 62 (379-387) ◽  
pp. 250-266 ◽  
Keyword(s):  
Dielectric Constant ◽  
Low Temperatures ◽  
Tuning Fork ◽  
Dielectric Constants ◽  
The Past ◽  
Method Of Measurement ◽  
The Given ◽  
Past Summer

In several previous communications we have described the investigations made by us on the dielectric constants of various frozen organic bodies and electrolytes at very low temperatures. In these researches we employed a method for the measurement of the dielectric constant which consisted in charging and discharging a condenser, having the given body as dielectric, through a galvanometer 120 times in a second by means of a tuning-fork interrupter. During the past summer we have repeated some of these determinations and used a different method of measurement and a rather higher frequency. In the experiments here described we have adopted Nernst’s method for the measurement of dielectric constants, using for this purpose the apparatus as arranged by Dr. Nernst which belongs to the Davy-Faraday Laboratory.

scholarly journals Franco-Prussian campaign of 1870-1871 in perception of the novice British war correspondent A. Forbes

2020 ◽  
pp. 101-111
Author(s):  
Aleksei Vlasov
Keyword(s):  
Intellectual History ◽  
Professional Practice ◽  
Professional Activity ◽  
Object Description ◽  
The Past ◽  
Personal Attitudes ◽  
The Subject ◽  
Xix Century ◽  
Journalistic Practice

The object of this article is professional activity of the British war correspondent Archibald Forbes during the Franco-Prussian War of 1870-1871. The subject is the perception and reflection of military realities (1870-1871) by the novice journalist. The goal consists in determination of the mechanisms of perception of participants and realities of the Franco-Prussian confrontation of 1870-1871 by the British correspondent A. Forbes. Intellectual history and imagological approach comprise the methodological framework of this research. Based on the analysis of documentary evidence left by A. Forbes, which describes the events of 1870-1871, the author was able to trace the evolution of Forbes’ perception of the Franco-Prussian campaign of 1870-1871. The conclusion is made on gradual changes in Forbe’s perception and reflection of war realities. The initial admiration was replaced by the professional subject-object description. However, his stance on parties to the conflict remained unchanged. The author assumes that A. Forbes had particular personal attitudes, but his perception of the war of 1870-1871 has evolved. The acquired results may be valuable in studying journalistic practice, as well as mutual perception of European ethnoses. The scientific novelty lies in a comprehensive approach towards the phenomenon at hand: the author examines not only the mechanisms of perception as such, but also their transformation influenced by various factors. This research made a transition from the widespread study of biographies and activity of correspondents of the XIX century to an extensive culturological and intellectual approach in consideration of professional practice of journalists of the past.

Homeostatic response of Aptian gymnosperms to changes in atmospheric CO2 concentrations

Geology ◽  
2021 ◽  
Author(s):  
Germán Mora ◽  
Ana M. Carmo ◽  
William Elliott
Keyword(s):  
Stomatal Closure ◽  
Carbon Assimilation ◽  
Atmospheric Co2 ◽  
The Past ◽  
A Value ◽  
Co2 Concentrations ◽  
Bulk Organic Matter ◽  
The Subject ◽  
Atmospheric Co2 Concentrations ◽  
Homeostatic Response

The sensitivity of plant carbon isotope fractionation (13Δleaf) to changes in atmospheric CO2 concentrations (Ca) is the subject of heavy debate, with some studies finding no sensitivity, while others show a strong dependency. We tested the hypothesis of photosynthetic homeostasis by using δ13C of n-alkanes, cuticles, and bulk organic matter of gymnosperm-rich rocks (Arundel Clay) from two sites deposited during the Aptian, a time that experienced significant Ca variations. Our results show no effect of Ca on 13Δleaf, and a relatively constant Ci/Ca (0.64 ± 0.04, 1σ; i—intercellular space), a value that is similar to that of modern gymnosperms. These results suggest that Aptian gymnosperms used homeostatic adjustments with rising Ca, probably involving increased carbon assimilation and/or stomatal closure, a response also found in modern gymnosperms. The similarity between Aptian and modern gymnosperms suggests that the processes responsible for regulating CO2 and water vapor exchange during photosynthesis have remained unaltered in gymnosperms for the past 128 m.y.

scholarly journals On the direct determination of the electrostatic moments of molecules

1929 ◽  
Vol 124 (795) ◽  
pp. 689-698 ◽  
Keyword(s):  
Dielectric Constant ◽  
Direct Determination ◽  
Negative Temperature ◽  
Dielectric Constants ◽  
Temperature Coefficients ◽  
Different Temperatures

According to Faraday's ideas, the specific inductive capacity of a substance is due to the polarisation of the molecules as wholes. This is the basis of the old Clausius-Mosotti theory of dielectrics, on which it is shown first that the polarisation P is proportional to the polarising field, i. e. , P = k E, k being the dielectric constant, and second that δ being the density of the dielectric, k - 2/ k + 2 ·1/δ = constant. Now it is known that some substances have large negative temperature coefficients for their dielectric constants which cannot thus be accounted for. To provide for this Debye proposed the theory that the molecules were permanently polarised and that they were systematically orientated in the field. This leads to the equation k - 2/ k + 2 = a T -1 + b T -2 , to represent the change of specific inductive capacity with temperature. This theory has been developed by Gans and others, and a number of measurements have been made by Smyth and others, who have found the molecular moments of many substances by measuring the dielectric constants at different temperatures.

Dielectric constant measurements of thin films and liquids using terahertz metamaterials

RSC Advances ◽  
2016 ◽  
Vol 6 (73) ◽  
pp. 69381-69386 ◽  
Author(s):  
S. J. Park ◽  
S. A. N. Yoon ◽  
Y. H. Ahn
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Polymer Films ◽  
Dielectric Constants ◽  
Polar Liquids ◽  
Terahertz Metamaterials

In this paper, we demonstrate that terahertz (THz) metamaterials are powerful tools for determination of dielectric constants of polymer films and polar liquids.

scholarly journals The diamagnetic susceptibilities of salts forming ions with inert gas configurations - Part I—The halides of sodium and potassium

1934 ◽  
Vol 147 (860) ◽  
pp. 88-100 ◽  
Keyword(s):  
Diamagnetic Susceptibility ◽  
Theoretical Work ◽  
Systematic Investigation ◽  
Inert Gas ◽  
Experimental Conditions ◽  
The Past ◽  
The Subject ◽  
Complete Investigation ◽  
Sodium And Potassium ◽  
Quantitative Nature

Although the subject of diamagnetic susceptibility has attracted the attention of many experimental and theoretical investigators during the past decade, it is remarkable that no complete systematic investigation of the susceptibilities of salts forming ions with inert gas configurations has been made. As a result, in comparing experimental and theoretical work, results for various salts obtained by quite different methods are used in conjunction with one another, and it is hardly surprising that the agreement should be of an approximate quantitative nature only in view of the wide discordance of the experimental results. The work of Ikenmeyer is the most complete investigation, but here the susceptibilities of certain salts, notably the fluorides, have not been measured. This is a serious omission for the data upon fluorides should prove to be amongst the most interesting. The present investigation is part of an attempt to obtain a series of results under the same experimental conditions and with the same apparatus, in order that the comparative values so obtained may be as accurate as possible.

scholarly journals Use of Dispersive Liquid-Liquid Microextraction and UV-Vis Spectrophotometry for the Determination of Cadmium in Water Samples

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
J. Pérez-Outeiral ◽  
E. Millán ◽  
R. Garcia-Arrona
Keyword(s):  
Water Samples ◽  
Limit Of Detection ◽  
Experimental Conditions ◽  
Cadmium Determination ◽  
A Value ◽  
Relative Standard ◽  
Potential Applicability ◽  
Dispersive Liquid Liquid Microextraction ◽  
Liquid Microextraction

A simple and inexpensive method for cadmium determination in water using dispersive liquid-liquid microextraction and ultraviolet-visible spectrophotometry was developed. In order to obtain the best experimental conditions, experimental design was applied. Calibration was made in the range of 10–100 μg/L, obtaining good linearity (R2 = 0.9947). The obtained limit of detection based on calibration curve was 8.5 μg/L. Intra- and interday repeatability were checked at two levels, obtaining relative standard deviation values from 9.0 to 13.3%. The enrichment factor had a value of 73. Metal interferences were also checked and tolerable limits were evaluated. Finally, the method was applied to cadmium determination in real spiked water samples. Therefore, the method showed potential applicability for cadmium determination in highly contaminated liquid samples.

Annual growth patterns in the inner shell layer of Mytilus edulis L.

1976 ◽  
Vol 56 (3) ◽  
pp. 723-731 ◽  
Author(s):  
R. A. Lutz
Keyword(s):  
Age Determination ◽  
Growth Patterns ◽  
Shell Morphology ◽  
Fossil Species ◽  
The Past ◽  
Growth Increments ◽  
Surface Shell ◽  
The Subject ◽  
Logical Research

INTRODUCTIONMolluscan age determination has long been the subject of both biological and paleonto-logical research (Mossop, 1922 a, b; Haskin, 1954; Merrill, Posgay & Nichy, 1965; Andrews, 1972). Several workers have listed difficulties associated with traditional methods of determining the age of an organism based upon surface shell morphology (Pannella & MacClintock, 1968; Farrow, 1971, 1972; Berry, 1971). Others, such as Craig & Hallum (1963) have attempted, with moderate success, to circumvent these problems statistically by using size-frequency relationships, but such methods are of little value in age analysis of isolated individuals. The principal difficulty encountered in shell surface analyses arises from an inability to distinguish spawning and disturbance lines from annual marks. Problems associated with this separation have been reduced over the past decade by the discovery of daily and tidal periodicity structures within the shells of numerous Recent and fossil species of pelecypods (Barker, 1964,1970; Pannella & MacClintock, 1968; Clark, 1968; House & Farrow, 1968; Farrow, 1971, 1972). The biological and paleontological significance of such growth increments have been discussed at length by Pannella & MacClintock (1968), Barker (1970), and Clark (1974). When present in continuous sequences, these periodicity structures facilitate an accurate age determination of individual specimens.

scholarly journals Women's Institutes in Imperial Russia in the wording of the normative documents (1764 – early XX century): terms, typology, dates

2021 ◽  
pp. 110-129
Author(s):  
Varvara Vital'evna Ponomareva
Keyword(s):  
Normative Documents ◽  
The Past ◽  
Imperial Russia ◽  
Class Composition ◽  
History Of ◽  
The Subject ◽  
The Russian Empire ◽  
First Time ◽  
Departmental Affiliation

The subject of this research is the foundation of women’s education system in the Russian Empire, namely of the Office of the Institutions of Empress Maria, which totaled up to three dozen by the early XX century. Actualization of the knowledge about the best examples of the Russian school in the past is determined by the fundamental importance of education in the context of ongoing modernization of the country. The topic of Women's institutes of Imperial Russia, which existed for over 150 years, is poorly studied. Despite the extensive source base, in the historical literature one can often come across improper names of the institutes, determination of their departmental affiliation, class composition of the students, as well as incorrect dating and topography. Using the historical-systemic and typological analysis, the author determines and clarifies the conceptual framework of the problematic as a necessary research toolset. The author's contribution to selected topic consists in discovery of a wide variety of sources, including those introduced into the scientific discourse for the first time, accurate names of the institutes and variations in the official documents and everyday practice., their renaming and the causes. The article also traces the dynamics of changes in the class and confessional composition of students since the establishment of the institutes until the beginning of the XX century. Subordination and departmental affiliation at different stages of the history of these institutes is clarified.

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