scholarly journals The rate of production of helium from radium

1908 ◽  
Vol 81 (547) ◽  
pp. 280-286 ◽  
Keyword(s):  
Royal Society ◽  
Atomic Weight ◽  
Experimental Results ◽  
Gaseous Products ◽  
Direct Measurements ◽  
Gas Pressures

Some time ago I communicated a paper to the Society entitled “Note or the Use of the Radiometer in Observing Small Gas Pressures: Application to the Detection of the Gaseous Products produced by Radio-active Bodies.” In the course of the experiments recorded in that paper it was shown that a pressure of the fifty millionth of an atmosphere could easily be detected by radiometer motion, and that the helium produced by radioactive processes from some 10 milligrammes of bromide of radium could be definitely detected after a few hours. This led me to desire some direct measurements of the amount of helium produced by radium, and through the kindness of the Royal Society in allowing me the use of some radium chloride belonging to them I am able to give a condensed abstract of the experimental results so far obtained. The salt employed was the 70 milligrammes of radium chloride prepared by Dr. T. E. Thorpe, P. R. S., for his determination of the atomic weight of radium, the preparation of which is fully described in ‘Roy. Soc. Proc., A, vol. 80, p. 298.

scholarly journals XIII. Revision of the atomic weight of gold

1889 ◽  
Vol 180 ◽  
pp. 395-441 ◽  
Keyword(s):  
Royal Society ◽  
Original Work ◽  
Atomic Weight ◽  
The Other ◽  
Organic Substances ◽  
Modern Methods ◽  
Gold Compounds ◽  
Chemical Section

Until lately gold ranked among the elementary substances of which the general properties had been well ascertained, but in regard to the atomic weights of which our knowledge was least satisfactory. That this constant should be determined as accurately as possible for gold was desirable in view of its bearing on the precise place assigned the metal in the “periodic” classification of the elements based on the ideas of Newlands, Odling, Mendelejeff, and L. Meyer. Furthermore, an exact know­ ledge of the atomic weight of gold might be conveniently applied in the determination of the atomic weights of some of the other elements. A practical laboratory reason for desiring to possess a trustworthy value for this constant was also presented by the facility with which gold compounds of many organic substances may be prepared, and the ease with which their composition may be ascertained by simple ignition in the air and weighing of the residual gold, the results leading to a knowledge of molecular composition when the atomic value of the weight of the metal obtained is assumed to be known. For the last three years and a half I have been occupied, during a large part of such time as has been available for original work, in devising and carrying out experiments aiming at the redetermination of the constant in question. The difficulties met with have been greater than were at first looked for, and have led to much time and labour being consumed in attempts to overcome them. About two years ago, when this work was already well under way but still in progress, there appeared the results of experiments aiming at the same end, by Kruss in Germany and by Thorpe and Laurie in England—experiments made with the care and accu­racy of modern methods, and apparently deserving of much confidence. My own work, however, was continued, as we cannot have too many careful independent determinations of atomic weights by different workers, and as I had used to a con­siderable extent other procesess than those on which the newly published determina­tions were based, while the chemists named had employed, in the main, one and the same method. A preliminary notice of my work was read in the Chemical Section of the British Association at the Manchester meeting of 1887. The details of my experiments and the results which I have reached are now laid before the Royal Society.

scholarly journals III.—On the Gradual Production of Luminous Impressions on the Eye: Part II. being a description of an Instrument for producing isolated luminous impressions on the eye of extremely short duration, and for measuring their intensity

1861 ◽  
Vol 22 (1) ◽  
pp. 33-39
Author(s):  
William Swan
Keyword(s):  
Short Duration ◽  
Royal Society ◽  
Experimental Results ◽  
Experimental Science ◽  
Full Effect ◽  
The Subject ◽  
Time Required

In 1849 I presented to the Royal Society of Edinburgh a paper “On the Gradual Production of Luminous Impressions on the Eye.” The object of that communication was to investigate the laws of the production of visual impressions. The subject was then new; for although the fact that light requires a certain time to produce its full effect on the eye had been noticed at comparatively early periods, yet no one, so far as I am aware, had attempted to measure that time; and the whole subject of the production of visual impressions, regarded as a branch of experimental science, was quite untouched. I have frequently wished to resume a subject of inquiry which seems to me to merit more attention than it has hitherto received, and which I have not as yet been able to discuss so completely as I could have desired. Various portions of it demand more extended experiments. Among these may be specified, the examination of isolated impressions of shorter duration than my limited instrumental means had enabled me to observe; a more careful determination of the time required for light to produce its complete effect on the eye; and a series of observations on the eyes of various individuals, so that any personal peculiarity of vision, which might affect results derived exclusively from experiments on my own eye, might be eliminated. These, and other subjects of inquiry, I hope sooner or later to overtake; and, indeed, I had anticipated before the end of the present session of the Society to have been able to obtain some experimental results. In this I have been disappointed, owing to the instruments required for my observations having taken a much longer time to make than I had expected.

Direct determination of triplet phases and enantiomorphs of non-centrosymmetric structures. II. Experimental results

1989 ◽  
Vol 45 (2) ◽  
pp. 182-187 ◽  
Author(s):  
K. Hümmer ◽  
E. Weckert ◽  
H. Bondza
Keyword(s):  
Direct Determination ◽  
Incident Beam ◽  
Experimental Results ◽  
Medium Size ◽  
Acta Cryst ◽  
Direct Measurements ◽  
Unit Cells ◽  
Independent Effects ◽  
Theoretical Considerations

Direct measurements of triplet phase relationships for non-centrosymmetric light-atom organic structures with medium-size unit cells are reported. The phase information can be extracted from the three- beam profiles of a Renningerψ-scan experiment. The measurements were carried out with a specialψ-circle diffractometer installed on a rotating Cu-anode generator. The incident-beam divergence is reduced to 0.02°. The experimental results confirm the theoretical considerations of paperIof this work [Hümmer & Billy (1986).Acta Cryst.A42, 127-133]. As triplet phases of +90° can be distinguished, the absolute structure can be determined unambiguously. The measurements show that the triplet-phase-dependent interference effects may be superposed on phase-independentUmweganregungorAufhellungeffects. By a comparison of theψ-scan profiles of two centrosymmetrically related three-beam cases, the triplet phases of which have opposite signs, it is possible to evaluate the phase-independent effects and to determine the value of the triplet phase with an accuracy of at least 90°.

scholarly journals I. Remarks on the atomic weight of beryllium

1883 ◽  
Vol 36 (228-231) ◽  
pp. 462-464
Keyword(s):  
Experimental Determination ◽  
Homologous Series ◽  
Royal Society ◽  
Chemical Society ◽  
Atomic Weight ◽  
Atomic Heat

In a reply to a note by Professor Emerson Reynolds “On the Atomic Weight of Glucinum or Beryllium,” presented to the Royal Society by Dr. Frankland on June 7th, 1883, Dr. Humpidge has made some critical observations concerning evidence which I adduced in favour of the value 9 or 9.2. I did not consider that these remarks called for notice at the time, as they were beside the question immediately under discussion, namely, the experimental determination of the atomic heat of the metal, but from the fact that they have been abstracted for various journals, and that greater prominence has been given to them than was perhaps originally intended by the author, I beg to be allowed to comment upon them, as my opinions have been entirely misrepresented. Dr. Humpidge states in allusion to me: “This chemist concludes from his experiments that glucinum is a dyad metal, and that its homologues are calcium, strontium, and barium, elements with which it has not the slightest analogy.” From this sentence it appears probable that Dr. Humpidge was not fully acquainted with the nature of the evidence advanced, which, how­ever, might be excusable, since though the two papers in which it was contained were read at the meetings of the Chemical Society, that “On Homologous Spectra” on March 15th, and that “On the Spectrum of Beryllium” on April 19th, they were not published in the Journal in time for him to have consulted them. The statement quoted above is precisely my argument. “The spec­trum of beryllium exhibits no marked analogy with the calcium, the magnesium, or the aluminium spectra, all of which are members of well-defined homologous series.”

Determination of Charge Coefficient of Piezoelectric Films Using a Combined Finite Element Model and Dynamic Loading Technique

2020 ◽  
Vol 835 ◽  
pp. 229-242
Author(s):  
Oboso P. Bernard ◽  
Nagih M. Shaalan ◽  
Mohab Hossam ◽  
Mohsen A. Hassan
Keyword(s):  
Finite Element ◽  
Dynamic Loading ◽  
Material Properties ◽  
Accurate Determination ◽  
Substrate Material ◽  
Experimental Results ◽  
Piezoelectric Composite ◽  
Piezoelectric Film ◽  
Piezoelectric Charge

Accurate determination of piezoelectric properties such as piezoelectric charge coefficients (d33) is an essential step in the design process of sensors and actuators using piezoelectric effect. In this study, a cost-effective and accurate method based on dynamic loading technique was proposed to determine the piezoelectric charge coefficient d33. Finite element analysis (FEA) model was developed in order to estimate d33 and validate the obtained values with experimental results. The experiment was conducted on a piezoelectric disc with a known d33 value. The effect of measuring boundary conditions, substrate material properties and specimen geometry on measured d33 value were conducted. The experimental results reveal that the determined d33 coefficient by this technique is accurate as it falls within the manufactures tolerance specifications of PZT-5A piezoelectric film d33. Further, obtained simulation results on fibre reinforced and particle reinforced piezoelectric composite were found to be similar to those that have been obtained using more advanced techniques. FE-results showed that the measured d33 coefficients depend on measuring boundary condition, piezoelectric film thickness, and substrate material properties. This method was proved to be suitable for determination of d33 coefficient effectively for piezoelectric samples of any arbitrary geometry without compromising on the accuracy of measured d33.

scholarly journals A parametric prediction of the Young’s modulus of polymers enhanced with ΜWCNTs

2018 ◽  
Vol 233 ◽  
pp. 00025
Author(s):  
P.V. Polydoropoulou ◽  
K.I. Tserpes ◽  
Sp.G. Pantelakis ◽  
Ch.V. Katsiropoulos
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Experimental Results ◽  
Scale Model ◽  
Fe Model ◽  
Multi Scale ◽  
Unit Cells ◽  
Random Dispersion

In this work a multi-scale model simulating the effect of the dispersion, the waviness as well as the agglomerations of MWCNTs on the Young’s modulus of a polymer enhanced with 0.4% MWCNTs (v/v) has been developed. Representative Unit Cells (RUCs) have been employed for the determination of the homogenized elastic properties of the MWCNT/polymer. The elastic properties computed by the RUCs were assigned to the Finite Element (FE) model of a tension specimen which was used to predict the Young’s modulus of the enhanced material. Furthermore, a comparison with experimental results obtained by tensile testing according to ASTM 638 has been made. The results show a remarkable decrease of the Young’s modulus for the polymer enhanced with aligned MWCNTs due to the increase of the CNT agglomerations. On the other hand, slight differences on the Young’s modulus have been observed for the material enhanced with randomly-oriented MWCNTs by the increase of the MWCNTs agglomerations, which might be attributed to the low concentration of the MWCNTs into the polymer. Moreover, the increase of the MWCNTs waviness led to a significant decrease of the Young’s modulus of the polymer enhanced with aligned MWCNTs. The experimental results in terms of the Young’s modulus are predicted well by assuming a random dispersion of MWCNTs into the polymer.

A Technique for the Laboratory Determination of Recirculation in Single Needle Dialysis

1993 ◽  
Vol 16 (2) ◽  
pp. 63-70 ◽  
Author(s):  
N.A. Hoenich ◽  
P.T. Smirthwaite ◽  
C. Woffindin ◽  
P. Lancaster ◽  
T.H. Frost ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Experimental Results ◽  
New Technique ◽  
Treatment Efficiency ◽  
Single Lumen ◽  
Theoretical Predictions ◽  
Lumen Catheter ◽  
A New Technique

Recirculation is an important factor in single needle dialysis and, if high, can compromise treatment efficiency. To provide information regarding recirculation characteristics of access devices used in single needle dialysis, we have developed a new technique to characterise recirculation and have used this to measure the recirculation of a Terumo 15G fistula needle and a VasCath SC2300 single lumen catheter. The experimentally obtained results agreed well with those established clinically (8.5 ± 2.4% and 18.4 ± 3.4%). The experimental results have also demonstrated a dependence on access type, pump speeds and fistula flow rate. A comparison of experimental data with theoretical predictions showed that the latter exceeded those measured with the largest contribution being due to the experimental fistula.

W. T. Astbury and Ross G. Harrison: the search for the molecular determination of form in the developing embryo

1980 ◽  
Vol 35 (2) ◽  
pp. 195-219 ◽  
Keyword(s):  
Royal Society ◽  
Limb Bud ◽  
Amphibian Embryo ◽  
X Ray ◽  
Biological Phenomena ◽  
Biology I ◽  
Series Of Experiments ◽  
Molecular Patterns ◽  
Molecular Determination

Amongst the Fellows elected to the Royal Society in 1941 were W. T. Astbury for his studies using X-ray analysis to study the structures of natural fibres, and amongst the Foreign Members elected that year was Ross G. Harrison for his contributions to embryology. Astbury and Harrison were very different in temperament, and worked in very different fields on either side of the Atlantic, yet they were united in their approach to the study of biological phenomena. Both Astbury and Harrison believed that the organization and form of biological materials whether wool fibres or the limb-bud in an amphibian embryo depended on molecular structure and pattern. Moreover both were concerned with dynamic aspects of form; Astbury’s greatest achievement was to demonstrate the dynamic, reversible folding and stretching of proteins in the k-m-e-f group, and Harrison looked to changing molecular patterns to account for changing symmetries in the developing embryo. It was this common approach that brought them together and led to Harrison spending a brief month in Leeds where they and K. M. Rudall performed what have been described as ‘truly progressive experiments in molecular biology’. I believe this short series of experiments illuminates the character and work of both Harrison and Astbury and illustrates the difficulties, practical and conceptual, in carrying out ‘progressive experiments’. I shall begin by reviewing briefly the embryological background of the time before going on to discuss in detail the approaches of Harrison and Astbury to their work and the outcome of their collaboration.

scholarly journals On the purification and testing of Selenion

1907 ◽  
Vol 79 (529) ◽  
pp. 167-174
Keyword(s):  
Royal Society ◽  
Atomic Weight

In 1895 I was enabled by a Royal Society grant to obtain about 100 lbs. weight of selenion of about 99·5-per-cent. selenion content. The grant was applied for to enable me to extend to selenion the investigations already made on purified sulphur. For the purpose of the investigation it was necessary to purify the selenion beyond the standard usual for material to be used in atomic weight investigations. This proved in the event to be impossible on account of the comparatively slight volatility of selenion dioxide, and the impossibility of preventing its formation in the course of the electric measurements I proposed to carry out. Meanwhile, I had prepared a great deal of very pure selenion, and began to investigate its properties—other than those of conduction, for which absolute purity is essential. The method of purification adopted was essentially that of Ekman and Petterson.

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