scholarly journals III. Bakerian lecture.—The rate of explosion in gases

1893 ◽  
Vol 184 ◽  
pp. 97-188 ◽  
Keyword(s):  
Chemical Reaction ◽  
Chemical Change ◽  
Moving Plate ◽  
Gaseous Mixtures ◽  
New Era ◽  
French Academy ◽  
Explosion Wave ◽  
Closed Tube ◽  
The Difference ◽  
Academy Of Sciences

The experiments described in this memoir were undertaken with two objects in the first place, to obtain information concerning the course of chemical change pursued by reacting gases; and, secondly, to examine the nature of the “explosion-wave” in gaseous mixtures discovered by M. Berthelot. The idea of using the rate of explosion as a means of determining the course of a chemical reaction occurred to me in 1877, when investigating the influence of steam on the union of carbonic oxide and oxygen. If steam acts as a carrier of oxygen to the carbonic oxide by a series of alternate reductions and oxidations, an increase in the amount of steam present, beyond that required to initiate the reaction, should be accompanied by an increase in the rate of combination up to a certain limit. Attempts were therefore made to detect such an increase by measuring the velocity of the flame in a tube. But while the difference in the rate of explosion between the nearly dry and the moist gases was well marked, the attempts to directly measure the rate of the explosion of the moist gases failed, owing to the great rapidity of the flame. In the spring of 1881 I attempted to measure the rate of explosion of carbonic oxide and oxygen with varying quantities of steam by photographing on a moving plate the flashes at the beginning and end of a closed tube 20 feet long. The two flashes appeared to be simultaneous to the eye, but no record of the rate was obtained, for the apparatus was broken to pieces by the violence of the explosion. Shortly after this attempt was made the first of the brilliant series of papers by MM. Berthelot and Vieille, and by MM. Mallard and Le Chateliek, was read before the French Academy of Sciences. The work of these French chemists has opened a new era in the theory of explosions.

scholarly journals IX. An account of trigonometrical operations in the years 1821, 1822 and 1823, for determining the difference of longitude between the Royal Observatories of Paris and Greenwich

1828 ◽  
Vol 118 ◽  
pp. 153-239 ◽  
Keyword(s):  
Royal Society ◽  
Royal Academy ◽  
The Difference ◽  
Academy Of Sciences ◽  
The Church ◽  
Royal Society Of London

In the year 1790, a series of trigonometrical operations was carried on by General Roy, in co-operation with Messrs. De Cassini, Mechain, and Legendre, for the purpose of connecting the meridians of Paris and Greenwich. In England, the work commenced with a base measured on Hounslow Heath, whence triangles were carried through Hanger Hill Tower and Severndroog Castle on Shooter’s Hill, to Fairlight Down, Folkstone Turnpike, and Dover Castle on the English coast; which last stations were connected with the church of Notre Dame at Calais, and with Blancnez and Montlambert upon the coast of France. An account of these operations will be found in the Philosophical Transactions for 1790. In the year 1821, the Royal Academy of Sciences and the Board of Longitude at Paris communicated to the Royal Society of London their desire, that the operations for connecting the meridians of Paris and Greenwich should be repeated jointly by both countries, and that commissioners should be nominated by the Royal Academy of Sciences and by the Royal Society of London for that purpose. This proposal having been readily acceded to, Messrs. Arago and Matthieu were chosen on the part of the Royal Academy of Sciences, and Lieut.-Colonel (then Captain) Colby and myself were appointed by the Royal Society to co-operate with them.

Quantitative Models for Complex Physical Systems

2014 ◽  
Vol 1061-1062 ◽  
pp. 1144-1147
Author(s):  
Jun Fu ◽  
Jin Zhao Wu ◽  
Ning Zhou ◽  
Hong Yan Tan
Keyword(s):  
Quantitative Analysis ◽  
State Space ◽  
Control Systems ◽  
Chemical Reaction ◽  
Metric Space ◽  
Manufacturing Systems ◽  
Quantitative Model ◽  
Hybrid Automata ◽  
Physical Systems ◽  
The Difference

We present a quantitative model, called metric hybrid automata, for quantifying the behaviors of complex physical systems, such as chemical reaction control systems, manufacturing systems etc. Due to the introduction of a metric, the state space of hybrid automata forms a metric space, in which the difference of states can be quantified. Furthermore, in order to reveal the distance of system behaviors, we construct the simulation distance and the bisimulation distance, which quantify the similarity of system behaviors. Our model provides the basis for quantitative analysis for those complex physical systems.

XXIII. On the water-barometer erected in the hall of the Royal Society

1832 ◽  
Vol 122 ◽  
pp. 539-574 ◽  
Keyword(s):  
Royal Society ◽  
Physical Science ◽  
The Other ◽  
Metallic Tube ◽  
French Academy ◽  
History Of ◽  
The Subject ◽  
The Common ◽  
Academy Of Sciences ◽  
Made In

I have for some time entertained an opinion, in common with some others who have turned their attention tot he subject, that a good series of observations with a Water-Barometer, accurately constructed, might throw some light upon several important points of physical science: amongst others, upon the tides of the atmosphere; the horary oscillations of the counterpoising column; the ascending and descending rate of its greater oscillations; and the tension of vapour at different atmospheric temperatures. I have sought in vain in various scientific works, and in the Transactions of Philosophical Societies, for the record of any such observations, or for a description of an instrument calculated to afford the required information with anything approaching to precision. In the first volume of the History of the French Academy of Sciences, a cursory reference is made, in the following words, to some experiments of M. Mariotte upon the subject, of which no particulars appear to have been preserved. “Le même M. Mariotte fit aussi à l’observatoire des experiences sur le baromètre ordinaire à mercure comparé au baromètre à eau. Dans l’un le mercure s’eléva à 28 polices, et dans Fautre l’eau fut a 31 pieds Cequi donne le rapport du mercure à l’eau de 13½ à 1.” Histoire de I'Acadérmie, tom. i. p. 234. It also appears that Otto Guricke constructed a philosophical toy for the amusement of himself and friends, upon the principle of the water-barometer; but the column of water probably in this, as in all the other instances which I have met with, was raised by the imperfect rarefaction of the air in the tube above it, or by filling with water a metallic tube, of sufficient length, cemented to a glass one at its upper extremity, and fitted with a stop-cock at each end; so that when full the upper one might be closed and the lower opened, when the water would fall till it afforded an equipoise to the pressure of the atmo­sphere. The imperfections of such an instrument, it is quite clear, would render it totally unfit for the delicate investigations required in the present state of science; as, to render the observations of any value, it is absolutely necessary that the water should be thoroughly purged of air, by boiling, and its insinuation or reabsorption effectually guarded against. I was convinced that the only chance of securing these two necessary ends, was to form the whole length of tube of one piece of glass, and to boil the water in it, as is done with mercury in the common barometer. The practical difficulties which opposed themselves to such a construction long appeared to me insurmount­able; but I at length contrived a plan for the purpose, which, having been honoured with the approval of the late Meteorological Committee of this Society, was ordered to be carried into execution by the President and Council.

scholarly journals Ivan Djaja (Jean Giaja) and the Belgrade School of Physiology

2011 ◽  
pp. S1-S13 ◽  
Author(s):  
P. R. ANDJUS ◽  
S. S. STOJILKOVIC ◽  
G. CVIJIC
Keyword(s):  
Associate Member ◽  
The Balkans ◽  
French Academy ◽  
Seminal Work ◽  
National Medical ◽  
Medical Academy ◽  
The University ◽  
Academy Of Sciences ◽  
Alexander Fleming

The founder of physiology studies in the Balkans and the pioneer of research on hypothermia, Ivan Djaja (Jean Giaja) was born 1884 in L’Havre. Giaja gained his PhD at the Sorbonne in 1909. In 1910 he established the first Chair of Physiology in the Balkans and organized the first Serbian Institute for Physiology at the School of Philosophy of the University of Belgrade. He led this Institute for more than 40 subsequent years. His most notable papers were in the field of thermoregulation and bioenergetics. Djaja became member of the Serbian and Croatian academies of science and doctor honoris causa of Sorbonne. In 1952 for the seminal work on the behavior of deep cooled warm blooded animals he became associate member of the National Medical Academy in Paris. In 1955 the French Academy of Sciences elected him as associate member in place of deceased Sir Alexander Fleming. Djaja died in 1957 during a congress held in his honor. He left more than 200 scientific and other papers and the golden DaVincian credo “Nulla dies sine experimento”. His legacy was continued by several generations of researchers, the most prominent among them being Stefan Gelineo, Radoslav Andjus and Vojislav Petrović.

On the water barometer erected in the hall of the Royal Society

1837 ◽  
Vol 3 ◽  
pp. 134-136
Keyword(s):  
Royal Society ◽  
Present Situation ◽  
Atmospheric Tides ◽  
Steam Boiler ◽  
Periodic Oscillations ◽  
French Academy ◽  
Different Temperatures ◽  
History Of ◽  
Additional Support ◽  
Academy Of Sciences

The author having long considered that a good series of observa­tions with a water barometer would be of great value as throwing light upon the theory of atmospheric tides, of the horary and other periodic oscillations of the barometer, and of the tension of vapourat different temperatures, was desirous of learning whether any such series of observations had ever been made. But he could meet with none having any pretensions to accuracy ; for neither those of Otto Guericke, in whose hands the water barometer was merely a philo­sophical toy, nor the cursory notices of the experiments of Mariotte upon this subject contained in the History of the French Academy of Sciences, can be considered as having any such claim. The difficul­ties which opposed the construction of a perfect instrument of this kind long appeared to be insurmountable; but the author at length proposed a plan for this purpose, which, having been approved of by the late Meteorological Committee of the Royal Society, was ordered by the President and Council to be carried into execution. The author then enters fully into the details of the methods he em­ployed for constructing the whole of the apparatus, and for placing in its present situation in the centre of the winding staircase con­ducting to the apartments of the Royal Society. The tube was very skilfully made by Messrs. Pellattand Co. at the Falcon Glass-house. It was 40 feet long, and one inch in diameter at its lower end; and so nearly cylindrical, throughout its whole extent, as to diminish only by two tenths of an inch at its upper end. A second tube of the same dimensions was also made as a provision in reserve against any accident happening to the first. These tubes were both securely lodged in a square case by means of proper supports. A small ther­mometer with a platina scale, was introduced into the upper end of the tube. An external collar of glass was united to that end by heat­ing it. This was done with a view of giving it additional support, and of preventing it from slipping. This end of the tube was then drawn out into a fine tube ready for sealing with the blowpipe; and a small stopcock was fitted on to it. The cistern of the barometer was formed by a small copper steam boiler, 18 inches long, 11 wide, and 10 deep, capable of being closed by a cock, and having at the bottom a small receptacle for holding the lower end of the tube, so as to allow of the water in the cistern being withdrawn, without dis­ turbing that contained in the tube.

scholarly journals IV.On a supposed alteration in the amount of astronomical aberration of light, produced by the passage of the light through a considerable thickness of refracting medium

1872 ◽  
Vol 20 (130-138) ◽  
pp. 35-39 ◽  
Keyword(s):  
Royal Academy ◽  
Angular Displacement ◽  
Focal Length ◽  
The Sun ◽  
Change Of Direction ◽  
The Subject ◽  
The Difference ◽  
North Polar ◽  
Academy Of Sciences ◽  
Right Ascension

A discussion has taken place on the Continent, conducted partly in the 'Astronomische Nachrichten,’ partly in independent pamphlets, on the change of direction which a ray of light will receive (as inferred from the Undulatory Theory of Light) when it traverses a refracting medium which has a motion of translation. The subject to which attention is particularly called is the effect that will be produced on the apparent amount of that angular displacement of a star or planet which is caused by the Earth’s motion of translation, and is known as the Aberration of Light. It has been conceived that there may be a difference in the amounts of this displacement, as seen with different telescopes, depending on the difference in the thicknesses of their object-glasses. The most important of the papers containing this discussion are:—that of Professor Klinkerfues, contained in a pamphlet published at Leipzig in 1867, August; and those of M. Hoek, one published 1867, October, in No. 1669 of the 'Astronomische Nachrichten,’ and the other published in 1869 in a communication to the Netherlands Royal Academy of Sciences. Professor Klinkerfues maintained that, as a necessary result of the Undulatory Theory, the amount of Aberration would be increased, in accordance with a formula which he has given; and he supported it by the following experiment:— In the telescope of a transit-instrument, whose focal length was about 18 inches, was inserted a column of water 8 inches in length, carried in a tube whose ends were closed with glass plates; and with this instrument he observed the transit of the Sun, and the transits of certain stars whose north-polar distances were nearly the same as that of the Sun, and which passed the meridian nearly at midnight. In these relative positions, the difference between the Apparent Right Ascension of the Sun and those of the stars is affected by double the coefficient of Aberration; and the merely astronomical circumstances are extremely favourable for the accurate testing of the theory. Professor Klinkerfues had computed that the effect of the 8-inch column of water and of a prism in the interior of the telescope would be to increase the coefficient of Aberration by eight seconds of arc. The observation appeared to show that the Aberration was really increased by 7'' 1. It does not appear that this observation was repeated.

Photodosimeter Badge System

PEDIATRICS ◽  
1985 ◽  
Vol 75 (2) ◽  
pp. 437-441
Author(s):  
Peter C. Scheidt ◽  
Phyllis M. Sternthal ◽  
Robert Anderson ◽  
Robert Studholme ◽  
Dolores A. Bryla ◽  
...  
Keyword(s):  
Child Health ◽  
Human Development ◽  
Optical Density ◽  
Action Spectrum ◽  
Radiant Energy ◽  
National Academy Of Sciences ◽  
High Concentration ◽  
Film Badge ◽  
The Difference ◽  
Academy Of Sciences

The Committee on Phototherapy in the Newborn of the National Academy of Sciences has recommended10 development of a compact system to continuously measure radiant energy exposure of infants treated with phototherapy. A small bilirubinimpregnated photodosimeter film badge was developed by the Beckman Instrument Company for this purpose and was used during the National Institute of Child Health and Human Development (NICHD) phototherapy study. This report summarizes the results of data obtained with this measurement device and briefly describes the performance of this system. METHODS The film badge dosimeter system consists of a 5.2x2.6-cm plastic badge composed of an imbedded disk of bilirubin cast in a polymeric substrate and sandwiched between two layers of clear plastic. Before exposure to light, the badge exhibits a high optical density at 460 nm due to a relatively high concentration of bilirubin. The optical density of the badge at 400 to 500 nm decreases as a function of the total dose of light within the action spectrum for the photodecomposition of bilirubin to which the badge has been exposed. Initial optical density at 460 nm is measured by a densitometer designed and dedicated specifically for this purpose. After exposure, the optical density is again measured by insertion into the densitometer; the total dosage, which is the time-integrated irradiance received by the badge during the photodecomposition process, is derived from the difference in optical density between the two readings. (A description of the calibration of the badge is available on request from Biometry Branch, Epidemiology and Biometry Research Program, National Institute of Child Health and Human Development, Bethesda, Maryland.)

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