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.

VIII. A critical study of spectral series.— Part III. The atomic weight term and its import in the constitution of spectra

1914 ◽  
Vol 213 (497-508) ◽  
pp. 323-420
Keyword(s):  
Periodic Table ◽  
Principal Series ◽  
Atomic Weight ◽  
The Other ◽  
Critical Study ◽  
Spectral Series ◽  
Present Communication ◽  
The Real ◽  
Real Relation ◽  
The One

The doublet and triplet separations in the spectra of elements are, as has long been known, roughly proportional to the squares of their atomic weights, at least whenelements of the same group of the periodic table are compared. In the formulæ which give the series lines these separations arise by certain terms being deducted from the denominator of the typical sequences. For instance, in the alkalies if the p -sequence be written N/D m 2 , where D m = m +μ+α/ m the p -sequence for the second principal series has denominator D—Δ, and we get converging doublets; whereas the constant separations for the S and D series are formed by taking S 1 (∞) = D 1 (∞) = N/D 1 2 and S 2 (∞) = D 2 (∞)= N/(D 1 —Δ) 2 . It is clear that the values of Δ for the various elements will also be roughly proportional to the squares of the atomic weights. For this reason it is convenient to refer to them as the atomic weight terms. We shall denote them by Δ in the case of doublets and Δ 1 and Δ 2 in the case of triplets, using v as before to denote the separations. Two questions naturally arise. On the one hand what is the real relation between them and the atomic weights, and on the other what relation have they to the constitution of the spectra themselves ? The present communication is an attempt to throw some light on both these problems.

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.

scholarly journals Overshooting calibration and age determination from evolved binary systems

2018 ◽  
Vol 615 ◽  
pp. A62 ◽  
Author(s):  
G. Valle ◽  
M. Dell’Omodarme ◽  
P. G. Prada Moroni ◽  
S. Degl’Innocenti
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Relative Error ◽  
Binary Systems ◽  
The Other ◽  
Helium Burning ◽  
Primary Star ◽  
Large Variability ◽  
Convective Core ◽  
The Masses

Aims. The capability of grid-based techniques to estimate the age together with the convective core overshooting efficiency of stars in detached eclipsing binary systems for main sequence stars has previously been investigated. We have extended this investigation to later evolutionary stages and have evaluated the bias and variability on the recovered age and convective core overshooting parameter accounting for both observational and internal uncertainties. Methods. We considered synthetic binary systems, whose age and overshooting efficiency should be recovered by applying the SCEPtER pipeline to the same grid of models used to build the mock stars. We focus our attention on a binary system composed of a 2.50 M⊙ primary star coupled with a 2.38 M⊙ secondary. To explore different evolutionary scenarios, we performed the estimation at three different times: when the primary is at the end of the central helium burning, when it is at the bottom of the RGB, and when it is in the helium core burning phase. The Monte Carlo simulations have been carried out for two typical values of accuracy on the mass determination, that is, 1% and 0.1%. Results. Adopting typical observational uncertainties, we found that the recovered age and overshooting efficiency are biased towards low values in all three scenarios. For an uncertainty on the masses of 1%, the underestimation is particularly relevant for a primary in the central helium burning stage, reaching − 8.5% in age and − 0.04 (− 25% relative error) in the overshooting parameter β. In the other scenarios, an undervaluation of the age by about 4% occurs. A large variability in the fitted values between Monte Carlo simulations was found: for an individual system calibration, the value of the overshooting parameter can vary from β = 0.0 to β = 0.26. When adopting a 0.1% error on the masses, the biases remain nearly unchanged but the global variability is suppressed by a factor of about two. We also explored the effect of a systematic discrepancy between the artificial systems and the model grid by accounting for an offset in the effective temperature of the stars by ± 150 K. For a mass error of 1% the overshooting parameter is largely biased towards the edges of the explored range, while for the lower mass uncertainty it is basically unconstrained from 0.0 to 0.2. We also evaluate the possibility of individually recovering the β value for both binary stars. We found that this is impossible for a primary near to central hydrogen exhaustion owing to huge biases for the primary star of + 0.14 (90% relative error), while in the other cases the fitted β are consistent, but always biased by about − 0.04 (− 25% relative error). Finally, the possibility to distinguish between models computed with mild overshooting from models with no overshooting was evaluated, resulting in a reassuring power of distinction greater than 80%. However, the scenario with a primary in the central helium burning was a notable exception, showing a power of distinction lower than 5%.

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 V.—Note on an Undescribed Area of Lower Greensand or Vectian in Dorset

1891 ◽  
Vol 8 (10) ◽  
pp. 456-458 ◽  
Author(s):  
A. J. Jukes-Browne
Keyword(s):  
Lower Cretaceous ◽  
Small Area ◽  
Upper Cretaceous ◽  
The Other ◽  
Present Communication ◽  
The Subject ◽  
Geological Magazine

Until recently no outcrop of the Vectian or Lower Greensand was known to occur between Lulworth on the coast of Dorset and the neighbourhood of Devizes in Wiltshire. It was supposed that, with the exception of a small area of Wealden in the Vale of Wardour, the whole of the Lower Cretaceous Series in Dorset and South Wilts was concealed and buried beneath the overlapping Upper Cretaceous strata. A recent examination of this district however has revealed two areas where the Vectian sands emerge from beneath the Gault. One of these has already been indicated in the pages of the Geological Magazine; the other is the subject of the present communication.

HISTORIOSOPHICAL PREREQUISITES FOR THE FORMATION OF THE CULT OF PERSONALITY IN THE BIOGRAPHIES OF V.I. LENIN 1924–1956

2021 ◽  
pp. 136-146
Author(s):  
Elena V. Barysheva ◽  
◽  
Dmitriy V. Morozov ◽  
Keyword(s):  
Historical Development ◽  
Historical Narrative ◽  
The Other ◽  
Historical Process ◽  
Formal Argument ◽  
Cult Of Personality ◽  
The One ◽  
The Masses ◽  
Plot Structure

The authors make an attempt to analyse on the basis of Hayden White’s theory of historical narrative historiosophical prerequisites for the formation of the cult of personality in the soviet biographies of V.I. Lenin published in 1924–1956. The basis of texts is a plot structure, implying, on the one hand, the existence of immutable laws of historical development, which humanity is forced to obey, and, on the other, a person who is able to learn them through the bitterness of defeats and put them at his service. The explanation of the facts of the historical narrative takes place by using two types of formal argument: Mechanism, which emphasizes the laws of historical development and the role of the masses in the historical process, and organicism, which gives high priority to V.I. Lenin himself and the party he created. The authors conclude that the articulation of the plot structure and types of formal argument embodied in the biographies becomes a prerequisite for the formation of the cult of personality. The latter implies the construction of an image of a person capable of transforming the reality, according to the concept of historical development that dominates in the party political historiography

scholarly journals Effects of Chronic Intracerebroventricular Infusion of RFamide-Related Peptide-3 on Energy Metabolism in Male Mice

2020 ◽  
Vol 21 (22) ◽  
pp. 8606
Author(s):  
Shogo Moriwaki ◽  
Yuki Narimatsu ◽  
Keisuke Fukumura ◽  
Eiko Iwakoshi-Ukena ◽  
Megumi Furumitsu ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Energy Metabolism ◽  
Food Intake ◽  
Energy Expenditure ◽  
Body Mass ◽  
The Other ◽  
Related Peptide ◽  
Intracerebroventricular Infusion ◽  
Brown Adipose ◽  
The Masses

RFamide-related peptide-3 (RFRP-3), the mammalian ortholog of avian gonadotropin-inhibitory hormone (GnIH), plays a crucial role in reproduction. In the present study, we explored the other functions of RFRP-3 by investigating the effects of chronic intracerebroventricular infusion of RFRP-3 (6 nmol/day) for 13 days on energy homeostasis in lean male C57BL/6J mice. The infusion of RFRP-3 increased cumulative food intake and body mass. In addition, the masses of brown adipose tissue (BAT) and the liver were increased by the administration of RFRP-3, although the mass of white adipose tissue was unchanged. On the other hand, RFRP-3 decreased O2 consumption, CO2 production, energy expenditure, and core body temperature during a short time period in the dark phase. These results suggest that the increase in food intake and the decrease in energy expenditure contributed to the gain of body mass, including the masses of BAT and the liver. The present study shows that RFRP-3 regulates not only reproductive function, but also energy metabolism, in mice.

Late Antiquity: The Age of Crowds?*

2020 ◽  
Vol 249 (1) ◽  
pp. 3-52
Author(s):  
Julio Cesar Magalhães de Oliveira
Keyword(s):  
Late Antiquity ◽  
Local Communities ◽  
The Other ◽  
Main Argument ◽  
Social Scientists ◽  
City Life ◽  
The People ◽  
Urban Protest ◽  
The One ◽  
The Masses

Abstract The objective of this article is to place the study of urban protest and violence in the period from about 300 to about 600 CE in a broader perspective and to subject the investigation of plebeian activism to the basic precepts of analysis of collective action developed by social scientists and historians studying other periods. Its main argument is that, contrary to wide held assumptions in the historiography, what characterized Late Antiquity was not simply the exacerbation of violence or its tighter control, but the crisis of aristocratic hegemony and the expansion of opportunities for popular intervention in city life. What has been perceived as the product fanaticism, irrationality and deprivation of the masses, of the manipulation of bishops and aristocrats or of the failure of the mechanisms of coercion was actually the result of a dramatic social change that, on the one hand, involved a new dynamic of power and, on the other, a shift in the way the people understood their role and power in local communities.

scholarly journals On the magnetic power of soft iron

1837 ◽  
Vol 3 ◽  
pp. 187-188
Keyword(s):  
Electric Current ◽  
Copper Wire ◽  
Complete Removal ◽  
The Other ◽  
Present Communication ◽  
Hard Steel ◽  
Electric Current Passing ◽  
Good Contact ◽  
The One ◽  
Single Helix

When free magnetism is developed by induction, and is not retained in that state by what has been termed the coercive force of hard steel, it has generally been considered that all the phenomena due to the existence of free magnetism cease on the removal of the inducing cause. The object of the present communication is to show that such is not the fact. From a variety of experiments described by the author, it appears that soft iron continued to exhibit strongly the attraction due to the developement of magnetism long after the means by which the magnetism had been originally excited had ceased to act. In these experiments, bars of soft iron, in the form of a horseshoe, had a single helix of copper wire wound round them, so that on the ends of the wire being brought into contact with the poles of a voltaic battery, the iron became an electromagnet. With one of these horse-shoes, while the connexion between the ends of the helix and the poles of the battery existed, the soft iron, having a keeper applied to its poles, supported 125 pounds it supported 56 pounds after that connexion had been broken, and continued to retain the power of supporting the same weight after an interval of several days, care having been taken not to disturb, during the time, the contact between the horse-shoe and its keeper. On this contact, however, being broken, nearly the whole attractive power appeared to be immediately lost. The author describes several instances of the same kind, particularly one in which the contact between the ends of the horse-shoe of soft iron and its keeper having been undisturbed during fifteen weeks, the attractive power continued undiminished. Although the interposition of a substance, such as mica or paper, between the ends of the horse-shoe and its keeper necessarily diminished the force of attraction, it did not appear to diminish the power of retaining that force. In a case where the electromagnet of soft iron and its keeper were equal semi-circles, the author found, what may appear singular, that the arrangement of the magnetism during the time that the electric current traversed the helix, appeared not to be the same as after the cessation of that current; in the one case similar, and in the other dissimilar, poles being opposed to each other at the opposite extremities of the two semi-circles. Whether the magnetism was originally developed in the soft iron by means of an electric current passing round it, or by passing over its surface the poles of an electromagnet, or those of a common magnet of hard steel, it appeared to possess the same power of retaining a large portion of the magnetism thus developed. The retention of the magnetism does not appear to depend upon the relative positions of the ends of the horse-shoe and the keeper remaining undisturbed, but on their contact remaining unbroken: for one keeper was substituted for another without diminution of this power; care being taken that the second should be in good contact with both ends of the horse-shoe before the complete removal of the first.

scholarly journals The scattering of α-particles by matter

1910 ◽  
Vol 83 (565) ◽  
pp. 492-504 ◽  
Keyword(s):  
Quantitative Measurement ◽  
Direct Evidence ◽  
Zinc Sulphide ◽  
The Other ◽  
Narrow Slit ◽  
Preliminary Note ◽  
Metal Foils ◽  
Strong Source ◽  
Α Particles

In a preliminary note (‘Roy. Soc. Proc.’ A, vol. 81, p. 174, 1908) on the above subject, experiments were described which gave direct evidence of the scattering of the α -particles. In those experiments a strong source of α -radiation was placed at one end of a long exhausted tube, and the α -particles, after passing through a narrow slit, fell upon a zinc sulphide screen sealed to the other end of the tube. When the pressure inside the tube was very low, the narrow line of scintillations which marked the place of incidence of the α -particles on the screen was well defined, but when the rays on their way to the screen passed through gas or through thin metal foils the edges of this line of scintillations became indistinct. The amount of scattering could be estimated for different foils by placing them in the path of the rays and noting the distribution of the scintillations on the screen. The present investigation was undertaken with a view to obtain a quantitative measurement of the scattering by determining the most probable angle through which an α -particle of definite range is turned by passing through a given thickness of matter. The following are the chief points investigated:— (1) Determination of the amount of scattering produced in different thicknesses of the same material. (2) Comparison of the amounts of scattering produced in different materials. (3) Relation between the velocity of the α -particles and the amount of their scattering.

Sign in / Sign up

Export Citation Format

Share Document