scholarly journals On the relation of hydrogen to palladium

1869 ◽  
Vol 17 ◽  
pp. 212-220 ◽  

It has often been maintained on chemical grounds that hydrogen gas is the vapour of a highly volatile metal. The idea forces itself upon the mind that palladium with its occluded hydrogen is simply an alloy of this volatile metal, in which the volatility of the one element is restrained by its union with the other, and which owes its metallic aspect equally to both constituents. How far such a view is borne out by the properties of the compound substance in question will appear by the following examination of the properties of what, assuming its metallic character, would have to be named Hydrogenium . 1. Density .—The density of palladium when charged with eight or nine hundred times its volume of hydrogen gas is perceptibly lowered; but the change cannot be measured accurately by the ordinary method of immersion in water, owing to a continuous evolution of minute hydrogen bubbles which appears to be determined by contact with the liquid. However, the linear dimensions of the charged palladium are altered so considerably that the difference admits of easy measurement, and furnishes the required density by calculation. Palladium in the form of wire is readily charged with hydrogen by evolving that gas upon the surface of the metal in a galvanometer containing dilute sulphuric acid as usual. The length of the wire before and after a charge is found by stretching it on both occasions by the same moderate weight, such as will not produce permanent distention, over the surface of a flat graduated measure. The measure was graduated to hundredths of an inch, and by means of a vernier, the divisions could be read to thousandths. The distance between two fine cross lines marked upon the surface of the wire near each of its extremities was observed.

1930 ◽  
Vol 51 (5) ◽  
pp. 769-776 ◽  
Author(s):  
Max B. Lurie

Under conditions closely simulating the natural modes of tuberculous infection in man normal guinea pigs have acquired tuberculosis by being exposed under two degrees of crowding to tuberculous cage mates in ordinary cages, where the food became soiled with excreta, bearing tubercle bacilli, and in special cages, with wire-mesh floors, where this source of infection was almost entirely eliminated. Guinea pigs were also exposed in the same room but not in the same cage with tuberculous animals. It was found that the relative tuberculous involvement of the mesenteric and tracheobronchial nodes showed a gradation of change from an almost completely alimentary infection to a completely respiratory infection. The disease involved the mesenteric nodes predominantly in the crowded ordinary cages, with much less or no affection of the tracheobronchial nodes. It was similarly, but less markedly, enteric in origin in the less crowded ordinary cages, the mesenteric nodes again being larger than the tracheobronchial nodes, but the difference in size was not so great. In the more crowded special cages the relative affection of these two groups of nodes alternated, so that in some the mesenteric, in some the tracheobronchial nodes were more extensively tuberculous. A disease characterized by less or no affection of the mesenteric nodes and by extensive lesions of the tracheobronchial nodes was seen in the less crowded special cages. Finally there was a massive tuberculosis of the tracheobronchial nodes with usually no affection of the mesenteric nodes in the frankly air-borne tuberculosis acquired by guinea pigs exposed in the same room but not to tuberculous cage mates. This gradation in the rô1e played by the enteric and respiratory routes of infection, as first the one and then the other becomes the more frequent channel of entrance for tuberculosis, would indicate that the penetration of tubercle bacilli by the one portal of entry inhibits the engrafting of tuberculosis in the tissues by way of the other portal of entry. It is apparent that in the special cages the opportunities for inhaling tubercle bacilli are at most equal to if not much less than in the ordinary cages; for in the latter dust from the bedding, laden with tubercle bacilli, is stirred up almost constantly by the animals, whereas in the special cages there is no bedding at all, and therefore, presumably, no more tubercle bacilli in the air than may occur in any part of the room. Nevertheless the route of infection was predominantly the respiratory tract in the special cages, especially in the less crowded, apparently because the enteric route had been largely eliminated. The greater predominance of the respiratory route amongst guinea pigs that acquired tuberculosis in the less crowded ordinary cages as compared to the lesser significance of this route in the more crowded ordinary cages would point in the same direction. These observations are in harmony with our knowledge that tuberculosis once implanted in an organism confers a certain degree of immunity to the disease. It is noteworthy that in a study of human autopsy material Opie (3) has found that when healed lesions are present in the mesentery focal tuberculosis in the lungs is seldom found, and that when first infection occurs by way of the lungs it tends to prevent the engrafting of the disease by way of the intestinal tract.


1998 ◽  
Vol 30 (04) ◽  
pp. 1027-1057 ◽  
Author(s):  
Philippe Picard

Modelling malaria with consistency necessitates the introduction of at least two families of interconnected processes. Even in a Markovian context the simplest fully stochastic model is intractable and is usually transformed into a hybrid model, by supposing that these two families are stochastically independent and linked only through two deterministic connections. A model closer to the fully stochastic model is presented here, where one of the two families is subordinated to the other and just a unique deterministic connection is required. For this model a threshold theorem can be proved but the threshold level is not the one obtained in a hybrid model. The difference disappears only when the human population size approaches infinity.


1878 ◽  
Vol 28 (2) ◽  
pp. 633-671 ◽  
Author(s):  
Alexander Macfarlane

The experiments to which I shall refer were carried out in the physical laboratory of the University during the late summer session. I was ably assisted in conducting the experiments by three students of the laboratory,—Messrs H. A. Salvesen, G. M. Connor, and D. E. Stewart. The method which was used of measuring the difference of potential required to produce a disruptive discharge of electricity under given conditions, is that described in a paper communicated to the Royal Society of Edinburgh in 1876 in the names of Mr J. A. Paton, M. A., and myself, and was suggested to me by Professor Tait as a means of attacking the experimental problems mentioned below.The above sketch which I took of the apparatus in situ may facilitate tha description of the method. The receiver of an air-pump, having a rod capable of being moved air-tight up and down through the neck, was attached to one of the conductors of a Holtz machine in such a manner that the conductor of the machine and the rod formed one conducting system. Projecting from the bottom of the receiver was a short metallic rod, forming one conductor with the metallic parts of the air-pump, and by means of a chain with the uninsulated conductor of the Holtz machine. Brass balls and discs of various sizes were made to order, capable of being screwed on to the ends of the rods. On the table, and at a distance of about six feet from the receiver, was a stand supporting two insulated brass balls, the one fixed, the other having one degree of freedom, viz., of moving in a straight line in the plane of the table. The fixed insulated ball A was made one conductor with the insulated conductor of the Holtz and the rod of the receiver, by means of a copper wire insulated with gutta percha, having one end stuck firmly into a hole in the collar of the receiver, and having the other fitted in between the glass stem and the hollow in the ball, by which it fitted on to the stem tightly. A thin wire similarly fitted in between the ball B and its insulating stem connected the ball with the insulated half ring of a divided ring reflecting electrometer.


2021 ◽  
Vol 29 (1) ◽  
pp. 36-61
Author(s):  
Michael Poznic ◽  
Rafaela Hillerbrand

Climatologists have recently introduced a distinction between projections as scenario-based model results on the one hand and predictions on the other hand. The interpretation and usage of both terms is, however, not univocal. It is stated that the ambiguities of the interpretations may cause problems in the communication of climate science within the scientific community and to the public realm. This paper suggests an account of scenarios as props in games of make-belive. With this account, we explain the difference between projections that should be make-believed and other model results that should be believed.


2017 ◽  
Vol 19 (3) ◽  
pp. 349-377
Author(s):  
Leonardo Niro Nascimento

This article first aims to demonstrate the different ways the work of the English neurologist John Hughlings Jackson influenced Freud. It argues that these can be summarized in six points. It is further argued that the framework proposed by Jackson continued to be pursued by twentieth-century neuroscientists such as Papez, MacLean and Panksepp in terms of tripartite hierarchical evolutionary models. Finally, the account presented here aims to shed light on the analogies encountered by psychodynamically oriented neuroscientists, between contemporary accounts of the anatomy and physiology of the nervous system on the one hand, and Freudian models of the mind on the other. These parallels, I will suggest, are not coincidental. They have a historical underpinning, as both accounts most likely originate from a common source: John Hughlings Jackson's tripartite evolutionary hierarchical view of the brain.


Dialogue ◽  
1982 ◽  
Vol 21 (3) ◽  
pp. 411-429
Author(s):  
David Braybrooke

A central feature of David Gauthier's impressively searching version of social contract theory is the principle of maximin relative advantage. Given certain assumptions—more than he originally thought—this principle may be described as calling for maximum equal advantage, which is easier to talk about; and I shall refer to the principle under this description. Maximum equal relative advantage is equivalent to minimum equal relative concession; hence the principle of maximum equal relative advantage has a twin and mirror, the principle of minimum equal relative concession. Relative advantage and relative concession are ratios with the same denominator, the difference for a given agent between the maximum utility (umax) that she might get from the societyt o be contracted for and the minimum utility (umin) that would give her an incentive to cooperate in establishing the society and in keeping it up. The numerator for the one ratio—relative advantage—is the difference between the utility that she is actually going to gain from society (ua) and her minimum cooperative utility (umin). The numerator for the other ratio—relative concession—is the difference between her maximum utility (umax) and the utility that she is going to get (ua), in other words, the amount of utility that she foregoes in not getting her maximum.


2018 ◽  
Vol 1 (1) ◽  
pp. 8-27
Author(s):  
Monica Manolachi

Censorship as a literary subject has sometimes been necessary in times of change, as it may show how the flaws in power relations influence, sometimes very dramatically, the access to and the production of knowledge. The Woman in the Photo: a Diary, 1987-1989 by Tia Șerbănescu and A Censor’s Notebook by Liliana Corobca are two books that deal with the issue of censorship in the 1980s (the former) and the 1970s (the latter). Both writers tackle the problem from inside the ruling system, aiming at authenticity in different ways. On the one hand, instead of writing a novel, Tia Șerbănescu kept a diary in which she contemplated the oppression and the corruption of the time and their consequences on the freedom of thought, of expression and of speech. She thoroughly described what she felt and thought about her relatives, friends and other people she met, about books and their authors, in a time when keeping a diary was hard and often perilous. On the other hand, using the technique of the mise en abyme, Liliana Corobca begins from a fictitious exchange of emails to eventually enter and explore the mind of a censor and reveal what she thought and felt about the system, her co-workers, her boss, the books she proofread, their authors and her own identity. Detailed examinations and performances of the relationship between writing and censorship, the two novels provide engaging, often tragi-comical, insights into the psychological process of producing literary texts. The intention of this article is to compare and contrast the two author’s perspectives on the act of writing and some of its functions from four points of view: literary, cultural, social and political.


The magnetic and other related properties of neodymium sulphate have been the subject of numerous investigations in recent years, but there is still a remarkable conflict of evidence on all the essential points. The two available determinations of the susceptibility of the powdered salt at low temperatures, those of Gorter and de Haas (1931) from 290 to 14° K and of Selwood (1933) from 343 to 83° K both fit the expression X ( T + 45) = constant over the range of temperature common to both, but the constants are not the same and the susceptibilities at room temperature differ by 11%. The fact that the two sets of results can be converted the one into the other by multiplying throughout by a constant factor suggested that the difference in the observed susceptibilities was due to some error of calibration. It could, however, also be due to the different purity of the samples examined though the explanation of the occurrence of the constant factor is then by no means obvious. From their analysis of the absorption spectrum of crystals of neodymium sulphate octahydrate Spedding and others (1937) conclude that the crystalline field around the Nd+++ ion is predominantly cubic in character since they find three energy levels at 0, 77 and 260 cm. -1 .* Calculations of the susceptibility from these levels reproduce Selwood’s value at room temperature but give no agreement with the observations-at other temperatures. On the other hand, Penney and Schlapp (1932) have shown that Gorter and de Haas’s results fit well on the curve calculated for a crystalline field of cubic symmetry and such a strength that the resultant three levels lie at 0, 238 and 834 cm. -1 , an overall spacing almost three times as great as Spedding’s.


Author(s):  
Jennifer Jenkins

This article discusses English in terms of its role as a contact language among expanding circle users of English from different first languages. It begins by observing both similarities between English as a Lingua Franca (ELF) and other lingua francas, and the difference in scale between them, with ELF involving a far higher number of people and first languages. The article goes on to explore empirical research into ELF, and its key findings: on the one hand, that certain “nonstandard” English forms are regularly preferred to “standard” (i.e. native) ones, and on the other, that ELF is far more affected by context and accommodation processes, and, therefore, far more diverse, than native Englishes. The notion of “community of practice,” it is argued, is, thus, more appropriate to ELF than that of “speech community.” The article concludes by considering three key areas of ELF research that need to be tackled.


2021 ◽  
Vol 52 (1) ◽  
pp. 36-77
Author(s):  
Claire Petitmengin

Abstract Both Buddhist meditation and micro-phenomenology start from the observation that our experience escapes us, we don’t see it as it is. Both offer devices that allow us to become aware of it. But, surprisingly, the two approaches offer few precise descriptions of the processes which veil experience, and of those which make it possible to dissipate these veils. This article is an attempt to put in parentheses declarative writings on the veiling and unveiling processes and their epistemological background and to collect procedural descriptions of this veiling and unveiling processes. From written and oral meditation teachings on the one hand, micro-phenomenological interviews applied to meditative experience and to themselves on the other hand, we identified four types of veiling processes which contribute to screen what is there, and ultimately to generate the naïve belief in the existence of an external reality independent of the mind: attentional, emotional, intentional and cognitive veils. The first part of the article describes these veiling processes and the processes through which they dissipate. It leads to the identification of several “gestures” conducive to this unveiling. The second part describes the devices used by meditation and by micro-phenomenology to elicit these gestures.


Sign in / Sign up

Export Citation Format

Share Document