An account of several new instruments and processes for determining the constants of a voltaic circuit

1843 ◽  
Vol 4 ◽  
pp. 469-471 ◽  
Keyword(s):  
The Other ◽  
Limited Extent ◽  
Practical Application ◽  
Present Communication ◽  
Electric Currents ◽  
Short Account ◽  
Electro Magnetic ◽  
Practical Object ◽  
Electric Effects ◽  
New Instruments

The author proposes in the present communication to give an account of various instruments and processes which he has employed during several years past for the purpose of investigating the laws of electric currents. He states that the practical object for which these instruments were originally constructed, was to ascertain the most advantageous conditions for the production of electric effects through circuits of great extent, in order to determine the practicability of communicating signals by means of electric currents to more considerable distances than had hitherto been attempted. Their use, however, is not limited to this special object, but extends equally to all inquiries relating to the laws of electric currents and to every practical application of this wonderful agent. As the instruments and processes described by the author are all founded on Ohm’s theory of the voltaic circuit, he commences with a short account of the principal results to which this theory leads, and shows how the clear ideas of electromotive forces and resistances, substituted for the vague notions of intensity and quantity which formerly prevailed, furnish us with satisfactory explanations of phenomena, the laws of which have hitherto been involved in obscurity and doubt. According to Ohm’s system, the force of the current is equal to the sum of the electromotive forces divided by the sum of the resistances in the circuit. The several electromotive forces and resistances which enter into the circuit of a voltaic battery are then defined; and having frequent occasion to refer to the laws of the distribution of the electric current in the various parts of a circuit, when a branch conductor is placed so as to divert a portion of the current from a limited extent of that circuit, the author directs particular attention to these laws. After recommending several new terms in order to express general propositions, without circumlocution and with greater precision, the author states the method of obtaining the constants of a circuit employed by Fechner, Lenz, Pouillet, &c., and then proceeds to explain the new method he has himself adopted. The principle of this method is the employment of variable instead of constant resistances, bringing, thereby, the currents in the circuits compared to equality, and inferring from the amount of the resistance measured out between two deviations of the needle, the electromotive forces and resistances of the circuit according to the particular conditions of the experiment; a method which requires no knowledge of the forces corresponding to different deviations of the needle. To apply this principle, it is requisite to have a means of varying the interposed resistance, so that it may be gradually changed within any required limits. The author describes two instruments for effecting this purpose; one intended for circuits in which the resistance is considerable, the other for circuits in which it is small. The Rheostat (for thus the inventor names the instrument under both its forms) may also be usefully employed as a regulator of a voltaic current, in order to maintain for any required length of time precisely the same degree of force, or to change it in any required proportion; its advantages in regulating electro-magnetic engines and in the operations of voltatyping, electro-gilding, &c. are pointed out.

scholarly journals XIII. The Bakerian lecture.—An account of several new instruments and processes for determining the constants of a voltaic circuit

1843 ◽  
Vol 133 ◽  
pp. 303-327 ◽  
Keyword(s):  
Electric Circuit ◽  
Original Research ◽  
Experimental Science ◽  
Electric Currents ◽  
Chemical Action ◽  
Short Account ◽  
High Expectations ◽  
Practical Applications ◽  
Theoretical Generalization ◽  
New Instruments

§ 1. I Intend in the present communication to give an account of various instruments and processes which I have devised and employed during several years past for the purpose of investigating the laws of electric currents. The practical object to which my attention has been principally directed, and for which these instruments were originally constructed, was to ascertain the most advantageous conditions for the production of electric effects through circuits of great extent, in order to determine the practicability of communicating signals by means of electric currents to more considerable distances than had hitherto been attempted. In this endeavour, guided by the theory of Ohm and assisted by the instruments I am about to describe, I have completely succeeded. But the use of the new instruments is not limited to this especial object; they will, I trust, be found of great assistance in all inquiries relating to the laws of electric currents, and to the various and daily increasing practical applications of this wonderful agent. An energetic source of light, of heat, of chemical action and of mechanical power, we only require to know the conditions under which its various effects may be most economically and energetically manifested, to enable us to determine whether the high expectations formed in many quarters of some of these applications are founded on reasonable hope, or on fallacious conjecture. The theory we now possess is amply sufficient to direct us rightly in this inquiry, but experiments have not yet been sufficiently multiplied to enable us to obtain, except in a few cases, the numerical values of the constants which enter into various voltaic circuits; and without this knowledge we can arrive at no accurate conclusions. § 2. The instruments and processes I am about to describe being all founded on the principles established by Ohm in his theory of the voltaic circuit, and this beautiful and comprehensive theory being not yet generally understood and admitted, even by many persons engaged in original research, I could scarcely hope to make my descriptions and explanations understood without prefacing them with a short account of the principal results which have been deduced from it. It will soon be perceived how the clear ideas of electro-motive forces and resistances, substituted for the vague notions of intensity and quantity which have been so long prevalent, enable us to give satisfactory explanations of most important phenomena, the laws of which have hitherto been involved in obscurity and doubt. Viewing the laws of the electric circuit from the point at which the labours of Ohm has placed us, there is scarcely any branch of experimental science in which so many and such various phenomena are expressed by formulæ of such simplicity and generality; in most of the physical sciences the facts of observation and experiment have kept pace with theoretical generalization, in this science alone they had gone on accumulating in prolific abundance without any successful attempt having been made to reduce them to mathematical ex­pression. But this is now happily effected, and what has hitherto been mere matter of speculative conjecture is removed into the domain of positive philosophy.

RANKING OF FUEL-AIR MIXTURES IN TERMS OF THEIR PROPENSITYTO DEFLAGRATION-TO-DETONATION TRANSITION

2020 ◽  
Author(s):  
S. M. FROLOV ◽  
◽  
V. I. ZVEGINTSEV ◽  
V. S. AKSENOV ◽  
I. V. BILERA ◽  
...  
Keyword(s):  
Detonation Wave ◽  
The Other ◽  
Practical Application ◽  
Deflagration To Detonation Transition ◽  
Other Hand ◽  
Pressure Gain Combustion ◽  
Reactive Mixture ◽  
Detonation Transition ◽  
The One ◽  
Energy Converting

The term "detonability" with respect to fuel-air mixtures (FAMs) implies the ability of a reactive mixture of a given composition to support the propagation of a stationary detonation wave in various thermodynamic and gasdynamic conditions. The detonability of FAMs, on the one hand, determines their explosion hazards during storage, transportation, and use in various sectors of the economy and, on the other hand, the possibility of their practical application in advanced energy-converting devices operating on detonative pressure gain combustion.

scholarly journals Interferential comparison of the red and other radiations emitted by a new cadmium lamp and the michelson lamp

1933 ◽  
Vol 139 (837) ◽  
pp. 202-218 ◽  
Keyword(s):  
Fine Structure ◽  
High Temperature ◽  
Wave Length ◽  
The Other ◽  
Reference Standard ◽  
Definite Evidence ◽  
Electro Magnetic ◽  
The Many ◽  
Red Radiation ◽  
Red Line

It is now generally recognised that future definitions of the units of length will probably be based on the length of a wave of visible light. At present the wave-length of the red radiation of cadmium serves as the basis of all measurements of the lengths of electro-magnetic waves which are perceptible by optical means, and provisional sanction has been given to measurements of length on the same basis, as an alternative to direct reference to the metre. Whether the cadmium red radiation provides the best reference standard for all measurements of length has not yet been definitely established. Two international committees, one representing spectroscopists and the other metrologists, have sanctioned standard specifications for cadmium lamps of the Michelson type from which the red radiation may be produced. The two specifications differ from one another in certain details, but both are subject to the same objections. These objections are directed partly against the high temperature at which it is necessary to run the lamp and partly against the high voltage required to excite the radiation. Therefore, such hyperfine structure and asymmetry as may be present in the red line of cadmium is likely to be masked in the Michelson lamp by a combination of two phenomena —the enhanced Doppler effect due to the high temperature of the radiating cadmium atoms, and the effect of the moderately high intensity of the electric field. Were this not so, it might be somewhat surprising that no definite evidence of fine structure or asymmetry had so far been observed in the red line from the Michelson lamp, notwithstanding the many careful examinations, with the aid of the most sensitive interferometers, to which this line has been subjected, in view of its importance as the reference standard for all other wave-lengths. Recently Nagaoka and Sugiura have recorded that they have observed slight evidences of structure in the red radiation when excited under special conditions in which great precautions were taken to ensure extreme sharpness of the line. It is believed, however, that no subsequent confirmation of this effect has yet been published.

scholarly journals XXI. On the construction of a new calorimeter for determining the radiating powers of surfaces in air; and its application to the surfaces of various mineral substances

1860 ◽  
Vol 150 ◽  
pp. 379-408
Keyword(s):  
Surrounding Medium ◽  
The Other ◽  
Absolute Amount ◽  
Present Communication ◽  
Atmospheric Air ◽  
Glass Bulb ◽  
Heated Body ◽  
Series Of Experiments ◽  
Quantity Of Heat ◽  
Limited Induction

When my paper on the Conductivity of various Substances was presented to the Society, it was intimated to me on the part of the Council of the Society, that it might be advisable to determine absolute instead of relative conductivities, the latter being alone attempted in my previous experiments. It has been partly in consequence of this intimation, as well as from the desire to make my investigations the more complete, that I have given my attention to the construction of a calorimeter which might serve for this purpose. The present communication contains a description of this instrument, with the results which it has enabled me to obtain respecting the absolute quantities of heat which emanate from the surfaces of certain substances under given conditions. 1. When a body is placed in atmospheric air (or any gas), the quantity of heat which is lost from its surface in a given time, when its temperature is higher than that of the surrounding medium, will be greater than if it were placed in a vacuum, other conditions remaining unaltered. In the latter case the heat escapes by simple radiation; in the other case a portion of the heat also escapes in consequence of the contact of the air with the surface of the heated body. Dulong and Petit ascertained by a careful series of experiments, the laws according to which the mercury contained in the bulb of a thermometer cools, or those which govern the quantity of heat which escapes from the surface of the containing bulb, when placed in a vacuum, in air, or in several kinds of gases. These experiments were made with the glass bulb naked, and also when it was silvered, so that the laws of radiation which they established were strictly in reference only to surfaces of glass and those of silver. Certain laws were identical in both these cases, and hence it was concluded, though by a limited induction, that the same laws were applicable to all other surfaces. They did not, however, give the absolute quantity of heat which, under given circumstances, and in a given time, emanates from the surfaces of the glass or silver with which they experimented. The instrument which I have constructed gives very easily this absolute amount of heat, as I believe, with very approximate accuracy.

Correlations of substituent effects on proton and fluorine chemical shifts with inverse ionization potentials

1967 ◽  
Vol 45 (24) ◽  
pp. 3143-3151 ◽  
Author(s):  
T. Schaefer ◽  
F. Hruska ◽  
H. M. Hutton
Keyword(s):  
Electric Fields ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Group Iv ◽  
The Other ◽  
Ionization Potentials ◽  
Time Dependent ◽  
Practical Application ◽  
Methyl Proton ◽  
Proton Chemical Shifts

The fluorine and proton chemical shifts in some geminally disubstituted vinylidene fluorides and ethylenes are discussed. For these compounds, at least, there are difficulties with an interpretation based on intramolecular time-dependent electric fields. On the other hand, the shifts correlate with the inverse ionization potentials of the substituents, indicating a paramagnetic effect arising from the second term in Ramsey's expression. It is suggested that the effect operates via the bonds and not across space. Methyl proton shifts in a series of substituted methyl compounds of group IV, V, and VI elements show similar correlations. A practical application of the correlation to spectral analysis problems is given.

scholarly journals Some nuclear transformations of beryllium and boron and the masses of the light elements

1935 ◽  
Vol 150 (869) ◽  
pp. 241-258 ◽  
Keyword(s):  
Spontaneous Emission ◽  
Periodic Table ◽  
Small Error ◽  
The Other ◽  
Light Elements ◽  
Mass Energy ◽  
Present Communication ◽  
Mass Data ◽  
The Masses ◽  
Α Particles

In a recent paper we showed that the nuclear transformations produced in lithium by bombarding the element with protons and with ions of heavy hydrogen were in complete accord with the laws of the conservation of mass-energy and of momentum. At the same time we pointed out that there were serious discrepancies between the mass-data and the transformation-data in some other cases, and we stressed the fact that the concordance for lithium was one between mass-differences, and gave no test of the correctness or otherwise of the absolute masses in terms of O 16 = 16·000. In the present communication we present the results of experiments on the transformation of beryllium and boron by protons and by ions of heavy hydrogen. It is shown that it is not possible to interpret these results on the mass-data at present available, and we indicate how the difficulties may be overcome by the assumption of a single small error in the mass-spectrographic value for the mass of He 4 . Beryllium So far as it is known beryllium consists of a single isotope,* the mass of which according to Bainbridge is 9·0155. This mass is greater than that of two α-partieles and a neutron (8·0043 + 1·0080§ = 9·0123) by nearly three million volts, and hence great difficulties have been en­countered in nuclear theory in accounting for the observed stability. It had been found by Rayleigh|| that the mineral beryl contained an abnormal quantity of helium, while the experiments of Curie-Joliot and of Chadwick¶ had shown that beryllium gave a copious emission of neutrons when bombarded by α-particles, but the most careful search has failed to give any evidence whatever for a spontaneous emission of particles from the element. Both lithium and boron, of atomic numbers 3 and 5 respectively, are very easily transformed by bombardment wit protons and with ions of heavy hydrogen, so that it was to be expected that beryllium, which lies between them in the periodic table, would also give effects when bombarded by the same ions. Observation of the energies evolved if the reactions are known with certainty, should then lead to values for the mass of Be 9 in terms of the masses of the other products of the transformations, which can be used to check the mass found by Bainbridge.

scholarly journals Politeness Strategies and Maxims in English for Islamic texts: A Sociolinguistic Analysis of Quran

2020 ◽  
Author(s):  
Hamid Gittan Jewad ◽  
Zargham Ghabanchi ◽  
Mohammad Ghazanfari
Keyword(s):  
Theoretical Framework ◽  
Qualitative Approach ◽  
The Other ◽  
Practical Application ◽  
Holy Quran ◽  
Politeness Strategies ◽  
The Face ◽  
The Holy Quran

This research tackles two chapters from the Holy Quran, the sura of Prophet Yusuf, and the sura of the Cave (al-Kahf) to find out whether the theories of Leech (1983) and Brown and Levinson (1987) can be applied to find out the positive and negative politeness strategies and the politeness maxims. The Leech’s model (1983) consists of six maxims, and for Brown and Levinson (1987), consists of two major politeness strategies. It consists of two principles of politeness, where one of them is positive, and the other is negative politeness. This study aims at investigating politeness strategies, and politeness principle linguistically in two Suras from the Holy Quran, how politeness strategies and politeness maxims used within the Holy Quran. This study tries to investigate the image of the main characters in the most sacred book. A qualitative approach is employed to provide interpretations of selected verses. In this paper, we will discuss the politeness strategies, positive and negative politeness strategies, and politeness maxims. The study falls into two parts. It begins briefly to overview the theoretical framework underlying politeness, in particular discussing some definitions of politeness and politeness principle and its maxims, exploring the face theory and its strategies by Brown and Levinson, and how far these strategies affect polite style then, dealing with politeness maxims by Leech. The other part displays a practical application of what has presented theoretically. Also, the researcher examined the politeness strategies, and politeness maxims of two Suras (Yusuf and Al-Kahf). Moreover, the study observed that approximately the majority of negative politeness in two suras then positive politeness, and the last one is politeness maxims.

scholarly journals Challenges and Failures in the Contemporary Arab Discourse

2021 ◽  
Vol 4 (6) ◽  
pp. 202-210
Author(s):  
Wafa Alkhatib ◽  
Mohammad Al-Qudah
Keyword(s):  
Political Discourse ◽  
The Other ◽  
Practical Application ◽  
The Masses

This research deals with the challenges and defeats faced by the contemporary Arab discourse in all its forms and aspects, especially as it is experiencing a strong crisis between international and regional inconsistencies, produced by the forces of globalization and its uneasy pressures. Our basic thesis in this article can be summarized as follows. First, we argue that, can we say that the contemporary Arab discourse is dependent on the other, or is it a slave to the makers of globalization?  Second, Does the Arab discourse in the present era issued by the same reference that was issued several decades ago, or is it reconsidering this reference to adapt to the circumstances and developments surrounding it? Or is it adapted between its Arab privacy, which starts from the constants and references that differ from our Arab reality and does not apply to our problems? To prove this, the article tries to shed the light on the credibility of the Arab political discourse, which constitutes a set of theoretical theses and hypothetical perceptions concerned with the author of the discourse only. It tries to reveal that the Arab political discourse does not touch the principle of practical application, as the recipients of political discourse feel disappointed and discredited because the author of the discourse derives his power from his authority and not from the authority of the masses, and loyalty is an absolute loyalty for him.

scholarly journals Collocations of dimension adjectives with the names of human body parts in Polish and Korean

2019 ◽  
Vol 26 ◽  
pp. 329-358
Author(s):  
Emilia Szalkowska-Kim
Keyword(s):  
Cultural Differences ◽  
Human Body ◽  
Comparative Research ◽  
The Other ◽  
Mutual Understanding ◽  
Body Parts ◽  
Practical Application ◽  
The World

This article presents the results of comparative research into the collocations of the names of human body parts with dimension adjectives. The aim of the analysis was to indicate the similarities, limitations and differences in the manners of conceptualising the world established in Polish and Korean, or more precisely: how both languages define the elements of the world of human body parts, and how they assign dimensions to the elements depending on the needs and experiences of native users of both. The results of the research could have a practical application in teaching both languages, facilitating students’ absorption of the lexis of the other language, and result in a deeper mutual understanding of linguistic and cultural differences..

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