scholarly journals VI. The effect of hydrogen on the discharge of negative electricity from hot platinum

1908 ◽  
Vol 208 (427-440) ◽  
pp. 247-273 ◽  
Keyword(s):  
Surface Layer ◽  
The State ◽  
Great Length ◽  
Series Of Experiments ◽  
The Wire

The effect of hydrogen on the discharge of negative electricity from hot platinum was examined by the writer in 1903 (‘Phil. Trans.,’ A, 352, vol. 202, 1903); it was found to produce a very large increase in the current carried by the discharge. At pressures below 0·1 millim. of mercury the leak was found to increase with the pressure and to fall when the pressure was reduced. The experiments in the paper just referred to were all done with nearly new platinum wires which had not been heated in the gas for any great length of time, because it was known that long continued heating caused the wire to disintegrate, its surface becoming covered with a network of cracks. The present paper contains an account of a series of experiments in which wires were heated for long periods in hydrogen, so that any gradual changes in the effect of the hydrogen could be observed. It appears that continued heating in hydrogen alters the character of the effects observed, so that the behaviour of an old wire may be very different from that of a new one. In the previous paper I suggested that the effect of hydrogen was due to the presence of hydrogen in the surface layer of the platinum, and this view appeared to be supported by the facts. Professor O. W. Richardson (‘Phil. Trans.,’ A, 413, vol. 207, 1906) puts forward a different theory, viz., that the hydrogen alters the state of the platinum, so that the effect may remain even after the removal of all the hydrogen.

scholarly journals The effect of hydrogen on the discharge of negative electricity from hot platinum

1908 ◽  
Vol 80 (540) ◽  
pp. 379-382
Keyword(s):  
Constant Temperature ◽  
Absolute Temperature ◽  
Great Length ◽  
Series Of Experiments ◽  
The Absolute ◽  
The Wire

The effect of hydrogen on the discharge of negative electricity from hot platinum was examined by the writer in 1903; it was found to produce a very large increase in the current. The experiments were all done with nearly new platinum wires which had not been heated in the gas for any great length of time, because it was known that long-continued heating causes the wire to disintegrate. The present paper contains an account of a series of experiments in which wires were heated for long periods in hydrogen, so that any changes in the effect of the hydrogen could be observed. It appears that continued heating in hydrogen alters the character of the effects observed so that the behaviour of an old wire may be very different from that of a new one. The following gives a short abstract of each section of the paper:— 1. Assuming that x = B p n , where x denotes the current per square centimetre of platinum at constant temperature, p is the pressure of the hydrogen, and B and n are quantities depending only on the temperature, and also that x = A θ ½ e –Q/2θ , where θ denotes the absolute temperature and A and Q depend only on the pressure; it is proved that: (1) n xθ -1– c , where α and c are constants; (2) Q = P — 2 α log p ; and (3) A = K p -c . These equations are shown to agree with the observations.

Effect of diamond burnishing parameters on the state of the processed surface layer of billets made of high-strength "30ХГСН2А-ВД" steel

2020 ◽  
pp. 82-86
Author(s):  
A.N. Shvetsov ◽  
D.L. Skuratov
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Strain Hardening ◽  
Processing Speed ◽  
Synthetic Diamond ◽  
High Strength ◽  
The State ◽  
Diamond Burnishing

The influence of the burnishing force, tool radius, processing speed and feed on the distribution of circumferential and axial residual strses, microhardness and the depth of strain hardening in the surface layer when pr ssing of "30ХГСН2А-ВД" steel with synthetic diamond "ACB-1" is considered. Empirical dependencies determining these parameters are given. Keywords diamond burnishing, strain hardening depth, circumferential residual stresses, axial residual stresses, microhardness. [email protected], [email protected]

The State of the Art of Rubber-Seal Technology

1987 ◽  
Vol 60 (3) ◽  
pp. 381-416 ◽  
Author(s):  
B. S. Nau
Keyword(s):  
State Of The Art ◽  
Test Procedure ◽  
Working Party ◽  
The State ◽  
Supporting Evidence ◽  
Wide Range ◽  
Lip Seals ◽  
Alternative Hypotheses ◽  
Series Of Experiments ◽  
Range Of Values

Abstract The understanding of the engineering fundamentals of rubber seals of all the various types has been developing gradually over the past two or three decades, but there is still much to understand, Tables V–VII summarize the state of the art. In the case of rubber-based gaskets, the field of high-temperature applications has scarcely been touched, although there are plans to initiate work in this area both in the U.S.A. at PVRC, and in the U.K., at BHRA. In the case of reciprocating rubber seals, a broad basis of theory and experiment has been developed, yet it still is not possible to design such a seal from first principles. Indeed, in a comparative series of experiments run recently on seals from a single batch, tested in different laboratories round the world to the same test procedure, under the aegis of an ISO working party, a very wide range of values was reported for leakage and friction. The explanation for this has still to be ascertained. In the case of rotary lip seals, theories and supporting evidence have been brought forward to support alternative hypotheses for lubrication and sealing mechanisms. None can be said to have become generally accepted, and it remains to crystallize a unified theory.

scholarly journals Chemical researches on the blood, and some other animal fluids

1832 ◽  
Vol 1 ◽  
pp. 416-418
Keyword(s):  
Thoracic Duct ◽  
The State ◽  
Perfect State ◽  
Slight Effect ◽  
Series Of Experiments

The author, after referring to those authorities by which he had been misled into the supposition that the colour of the blood depended on the presence of iron, until he had tried how slight effect it produced by infusion of galls, proceeds to a series of experiments which he has made upon chyle and on lymph, for the purpose of comparing their composition with that of bloody the examination of which is divided into three sections, in which he treats separately of the serum, the coagulum, and the colouring matter. The chyle employed in these analyses was collected by Mr. Brande while assisting Mr. Home and Mr. Brodie in their experiments on different animals; attention being always paid to the interval that had elapsed since the last meal; upon which circumstance its qualities were found to depend more than upon the animal from which it was taken. About four hours after a meal, the chyle is supposed to be in its most perfect state, and is then uniformly white, like milk. At longer periods it becomes more dilute, like milk and water, till at length, when an animal has fasted twenty-four hours, the fluid contained in the thoracic duct is reduced to the state of mere lymph.

Eineiige Zwillinge bei Triton ihre experimentelle Herstellung und ihre Regulation

1953 ◽  
Vol 2 (1) ◽  
pp. 49-68 ◽  
Author(s):  
Otto Mangold ◽  
Italo Testa
Keyword(s):  
Median Plane ◽  
Identical Twins ◽  
Great Length ◽  
Head Region ◽  
Normal Orientation ◽  
Series Of Experiments ◽  
The Right ◽  
Axial System ◽  
Early Gastrula ◽  
Better Than

SummaryTwins deriving from a single zygote were produced in Triton alpestris and Triton taeniatus by two different series of experiments. The first type of experiments proceeded, by means of a glass thread put on and cutting through the median plane of early gastrulae, to a division of these into two lateral (right and left) halves. These halves may give rise to normally formed identical twins (fig. 2), or to twins with more or less accentuated deficiencies on their inner sides (figg. 3 and 4). In extreme cases they may even produce left or right half-embryos, or much reduced malformations with very imperfect organ formation. Generally considered, the regolation in the head region is better than that in the tail one, and much better than in the trunk. Most of the heads show two eyes of equal size and normal position; in rare cases we encounter two eyes of different size, or synophthalmus or cyclopia. The «real» half-embryos have only one laterally situated eye (tab. 2). The normally formed identical twins deriving from half an egg each, develop into properly proportionned embryos of half the normal size; the resulting larvae reach the normal size of the equally-aged control larvae deriving from entire eggs, often before the stage of nourishment, (fig. 5, tab. 3).In the second series of experiments, an early gastrula was cut through in correspondence to the median plane, and then the complete presumptive epidermis of another gastrula and, respectively, of a third one, was stuck on to the wound surfaces of the halves in normal orientation (fig. 6). The right and the left combinations resulting therefrom give rise, in the original median line, to long, narrow and apparently somewhat too great neural plates, the external half-portion of which was fournished by the host half-gastrula and is somewhat more strongly developped than the inner half-portion deriving from the presumptive epidermis (fig. 7 a, b). This epidermis that was stuck on to the gastrula-halves' surfaces, takes part in the formation of the embryos either totally or at least for its greatest part. No perfect larvae will be formed (tab. 4). The head is always bilaterally developped, but it is often asymmetric and shows synophthalmous or cyclopic character (figg. 8, 9, 10, tab. 5). The trunk is sometimes normal (fig. 8 a), but it may also show an axial system of too great length (fig. 8 b), or dorsal deficiencies—often in the form of either symmetrical or asymmetrical Spina bifida—with dorsal incurvation (fig. 9 a, b). The tail can be either normal, or crooked, or defective, or doubled. In the best cases we see, in the first series of experiments, the regolation of the half-organiser of the gastrula-half into an entire organiser of half the normal size, while, in the second series of experiments, the regolation can produce an approximately normally sized entire organiser, which however, in the anterior head region is lacking of its full indutcive capacity.In both series of experiments the right hand member of the twins was observed to show inversion of the situs viscerum.

Effect of the State of a Surface Layer on the Properties of Pd–P Catalysts in the Hydrogenation of Alkylanthraquinones

2019 ◽  
Vol 60 (6) ◽  
pp. 808-817 ◽  
Author(s):  
L. B. Belykh ◽  
T. P. Sterenchuk ◽  
N. I. Skripov ◽  
V. V. Akimov ◽  
V. L. Tauson ◽  
...  
Keyword(s):  
Surface Layer ◽  
The State

scholarly journals II. On some phenomena exhibited by gun-cotton and gunpowder under special conditions of exposure to heat

1864 ◽  
Vol 13 ◽  
pp. 204-217
Keyword(s):  
Rapid Method ◽  
High Temperatures ◽  
Royal Society ◽  
Sufficient Accuracy ◽  
Hot Wire ◽  
Full Extent ◽  
Mechanical Condition ◽  
Series Of Experiments ◽  
The Wire ◽  
Made In

The experiments upon which I have been engaged for some time past, in connexion with the manufacture and properties of gun-cotton, have brought under my notice some interesting points in the behaviour of both gun. cotton and gunpowder, when exposed to high temperatures, under parti­cular conditions. I believe that these phenomena have not been previously observed, at any rate to their full extent, and I therefore venture to lay before the Royal Society a brief account of them. Being anxious to possess some rapid method of testing the uniformity of products obtained by carrying out General von Lenk’s system of manu­facture of gun-cotton, I instituted experiments for the purpose of ascer­taining whether, by igniting equal weights of gun-cotton of the same com­position, by voltaic agency, within a partially exhausted vessel connected with a barometric tube, I could rely upon obtaining a uniform depression of the mercurial column, in different experiments made in atmospheres of uniform rarefaction, and whether slight differences in the composition of the gun-cotton would be indicated, with sufficient accuracy, by a corre­sponding difference in the volume of gas disengaged, or in the depression of the mercury. I found that, provided the mechanical condition of the gun-cotton, and its position with reference to the source of heat, were in all instances the same, the indications furnished by these experiments were sufficiently accurate for practical purposes. Each experiment was made with fifteen grains of gun-cotton, which were wrapped compactly round the platinum wire; the apparatus was exhausted until the column of mercury was raised to a height varying from 29 inches to 29·5 inches. The flash which accompanied the deflagration of the gun-cotton was apparently similar to that observed upon its ignition in open air ; but it was noticed that an interval of time always occurred between the first application of heat (or incandescence of the wire) and the flashing of the gun-cotton, and that during this interval there was a very perceptible fall of the column of mercury. On several occasions, when the gun-cotton, in the form of “roving,” or loosely twisted strand, was only laid over the wire, so that it hung down on either side, the red-hot wire simply cut it into two pieces, which fell to the bottom of the exhausted vessel, without continuing to burn. As these results appeared to indicate that the effects of heat upon gun-cotton, in a highly rarefied atmosphere, differed importantly from those observed under ordinary circumstances, or in a very imperfect va­cuum, a series of experiments, under variously modified conditions, was instituted, of which the following are the most important.

On Sterility (‘HA X’), a medical work by Aristotle?

1999 ◽  
Vol 49 (2) ◽  
pp. 490-502 ◽  
Author(s):  
Philip J. van der Eijk
Keyword(s):  
Satisfactory Result ◽  
Female Body ◽  
The State ◽  
Great Length ◽  
Female Side ◽  
Medical Work ◽  
Wide Range ◽  
History Of ◽  
Physical Weakness

Whether its title, ύπέρ τοῦ μ⋯ γεννᾶν is authentic or not, the work transmitted as ‘Book X’ of Aristotle's History of Animals (HA) deals with a wide range of possible causes for failure to conceive and generate offspring. It sets out by saying that these causes may lie in both partners or in either of them, but in the sequel the author devotes most of his attention to problems of the female body. Thus he discusses the state of the uterus, the occurrence and modalities of menstruation, the condition and position of the mouth of the uterus, the emission of fluid during sleep (when the woman dreams that she is having intercourse with a man), physical weakness or vigour on awakening after this nocturnal emission, the occurrence of flatulence in the uterus and the ability to discharge this, moistness or dryness of the uterus, wind-pregnancy, and spasms in the uterus. Then he briefly considers the possibility that the cause of infertility lies with the male, but this is disposed of in one sentence: if you want to find out whether the man is to blame, the author says, just let him have intercourse with another woman and see whether that produces a satisfactory result (636bl 1–13; see also 637b23–4). The writer also acknowledges that the problem may lie in a failure of two otherwise healthy partners to match sexually, or as he puts it, to ‘run at the same pace’ ἲσοδρομῆσαι during intercourse, but he does not go into this possibility at great length (636b 15–23), and he proceeds to discuss further particulars on the female side.

scholarly journals Analysis of the Heating of Steel Wires During High Speed Multipass Drawing Process/ Analiza Nagrzewania Się Drutów Stalowych W Procesie Ciągnienia Wielostopniowego Z Dużymi Prędkosciami

2014 ◽  
Vol 59 (4) ◽  
pp. 1475-1480 ◽  
Author(s):  
M. Suliga
Keyword(s):  
Surface Layer ◽  
High Speed ◽  
Heated Surface ◽  
Experimental Studies ◽  
Drawing Process ◽  
Heat Accumulation ◽  
Steel Wires ◽  
Drawing Speed ◽  
The Wire ◽  
Surface Layer Thickness

Abstract The analysis of the heating of the wire including theoretical studies showed that in the multistage drawing process a increase drawing speed causes intense heating of a thin surface layer of the wire to a temperature exceeding 1100°C, which should be explained by the accumulation of heat due to friction at the interface between wire and die. It has been shown that with increasing of drawing speed the heated surface layer thickness measured at the exit of the wire from the dies is reduced significantly and at drawing speed of 25 m/s is equal to about 68 μm. The decrease in the thickness of this layer can be explained by a shorter time of heat transfer to the wire, which causes additional heat accumulation in the surface layer. Thus fivefold increase in drawing speed caused an approximately 110% increase in the temperature in the surface layer of the wire. Experimental studies have shown that the increase of drawing speed of 5 to 25 m/s will increase the temperature of the wire after coiled on the spool more than 400%.

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