scholarly journals III. On evaporation and dissociation.—Part III. A study of the thermal properties of ethyl oxide

1887 ◽  
Vol 178 ◽  
pp. 57-93 ◽  
Keyword(s):  
Thermal Properties ◽  
Ethyl Alcohol ◽  
Vapour Pressure ◽  
Chemical Combination ◽  
Thermal Constants ◽  
Similar Series ◽  
Vapour Density ◽  
The Subject ◽  
Density Expansion

In a memoir published in the Royal Society’s ‘Philosophical Transactions,’ 1886 (Part I.), p. 123, “On the Thermal Properties of Ethyl Alcohol,” we gave the results of a research on the vapour-pressures of alcohol, the densities of its vapour—both unsaturated and saturated—and the expansion and compressibility of liquid alcohol at various temperatures; and from these data were deduced the amounts of heat required to vaporize alcohol at those temperatures. Our object in these researches has been to compare carefully the behaviour of stable with that of unstable bodies, and, if possible, to acquire some clear ideas of the nature of chemical combination. But, as the properties of stable bodies are still to a great extent unknown, we have deemed it advisable to extend our research with the view of investigating this relationship; and for that purpose we have made a similar series of measurements of the thermal constants of ethyl oxide (C 2 H 5 ) 2 O. The data, and the deductions from the data, are the subject of the following memoir. Experiments on the vapour-pressure, vapour-density, expansion, and other properties of ether have been made by Regnault, Kopp, Pierre, Mendelejeff, Avenarius, and others, and their results shall be quoted when necessary.

I. A study of the thermal properties of ethyl alcohol

1885 ◽  
Vol 38 (235-238) ◽  
pp. 329-330
Keyword(s):  
Thermal Properties ◽  
Ethyl Alcohol ◽  
Gaseous State ◽  
Vapour Density

The abnormal vapour-density of many compounds has been ascribed to their dissociating to a greater or less degree while in the gaseous state. The compound molecule yields, with increase of temperature, a constantly increasing amount of those simpler molecules in to which it dissociates; and as this dissociation is attended with increase of volume, the vapour-density of the mixture of gaseous molecules decreases with rise of temperature. But this phenomenon is not confined to dissociating compounds alone. It is known that many, if not all, liquids acquire an abnormal vapour-density in proximity to their point of saturation.

scholarly journals XI. On evaporation and dissociation.―Part V. A study of the thermal properties of methyl-alcohol

1887 ◽  
Vol 178 ◽  
pp. 313-334 ◽  
Keyword(s):  
Acetic Acid ◽  
Thermal Properties ◽  
Critical Temperature ◽  
Methyl Alcohol ◽  
Boiling Point ◽  
Low Temperatures ◽  
Barium Oxide ◽  
Vapour Density ◽  
The Subject ◽  
Temperature And Pressure

In previous memoirs we have given the results of investigations of the thermal properties of ethyl-alcohol, acetic acid, and ethyl oxide (ether). The subject of the present paper is the vapour-pressures, vapour-densities, and expansion of methylalcohol; and from these results the heats of vaporisation have been deduced. The range of temperature is from —16° to the critical temperature 240°; and the range of pressure from 11 millims. to 60,000 millims. Preparation of pure methyl-alcohol. ―A finely crystallised sample of methyl oxalate was distilled with ammonia; the distillate was rectified, and when partially freed from water was distilled with quicklime. The distillate was again distilled from barium oxide, and then allowed to stand for some weeks over anhydrous copper sulphate; but the boiling-point was found to be by no means constant. It was then distilled six times over small quantities of sodium; and the rise of temperature during the last distillation was less than 0.1°. The boiling-point was 64.85° at 761.9 millims. A series of determinations of vapour-pressure at low temperatures was then made, and it was decided, before employing the alcohol for determinations of vapour-density, to re-distil it. It boiled at 64.95°, under the same pressure, 761.9 millims. Preliminary experiments were then carried out, with a view to determining the critical temperature and pressure; but the volume-tube burst, and the experiments were delayed until a new volume-tube had been calibrated. As the boiling-point of the alcohol was not absolutely constant, it was repeatedly fractionated, and the greater part was obtained, boiling at 64.7°, under 760 millims. pressure. The rise of temperature did not exceed 0.05° during the complete distillation.

scholarly journals Some moisture relations of colloids.—I. A comparative study of the rates of evaporation of water from wool, sand and clay

1923 ◽  
Vol 103 (720) ◽  
pp. 139-161 ◽  
Keyword(s):  
Vapour Pressure ◽  
Internal Factors ◽  
Effective Velocity ◽  
Physico Chemical ◽  
Free Moisture ◽  
The Subject ◽  
The Difference ◽  
Rate Of Evaporation ◽  
Drying Conditions ◽  
Air Processing

The operation of drying is one of dominating importance in many branches of industry, among which may be mentioned the drying and seasoning of timber and textiles, the curing of tea and tobacco, the manufacture of photographic films, glue and gelatin, pottery, paper, paints and varnishes, toffees, macaroni, milk and other dried foods and fruits; and “air-processing,” as it is called in America, is, in itself, an industry of considerable magnitude. It is not surprising, therefore, that much attention has been given by chemical engineers to the design of drying-plant, and a considerable literature on this subject exists. The theoretical side of the subject, however, has not been so thoroughly developed, and there are many gaps in our knowledge of the factors underlying the process of the evaporation of water from colloid materials. There are two main groups of factors governing the rate of evaporation of water from any kind of material. The first group is fairly well understood, and comprises all those factors that are external to the material concerned, such as the temperature and humidity of the drying atmosphere, and the effective velocity of the air over the surface of the stock. These factors are known generally as the “drying conditions.” The second group comprises what may be termed the internal factors, such as the chemical and physical properties of the material being dried and the changes that occur in these as the drying proceeds. These factors have not been so thoroughly investigated as the drying conditions, possibly on account of the difficulty of treating them from a purely physical and thermo-dynamic standpoint. They are, however, of no less importance industrially, while their study as a purely scientific problem is of much interest and may throw some light on the physical and physico-chemical nature of colloid materials. Moisture may exist in materials in at least two distinct forms: as free moisture adhering to the material and with a vapour pressure equal to that of water in bulk, and as “sorbed” moisture, the vapour pressure of which is always less than that of water in bulk. The rate of evaporation of water, under constant drying conditions, at any instant per unit of surface is proportional to the difference between the vapour pressure of the evaporating water and the pressure of the water-vapour in the adjacent atmosphere, i. e.

scholarly journals Some adsorption isothermals for a plane platinum surface

1929 ◽  
Vol 122 (790) ◽  
pp. 487-497 ◽  
Keyword(s):  
Adsorption Layer ◽  
Chemical Heterogeneity ◽  
Surface Films ◽  
Platinum Surface ◽  
Homogeneous Surface ◽  
Direct Technique ◽  
Chemical Combination ◽  
Great Ease ◽  
Metal Filament ◽  
The Subject

Quantitative experiments to establish the isothermals of adsorption on nonporous surfaces have only rarely been undertaken, owing mainly, no doubt, to the obvious difficulty of measuring the small absolute adsorptions on surfaces of manageable size. Yet it can well be held that many, if not all, of the uncertainties still attaching to the mechanism of adsorption and the constitution of the adsorption layer depend not upon any inherent complexity in the process itself, but upon the complicated geometrical and chemical con­ditions existing in the accessible surfaces of the porous materials, such as charcoal, that have so often been the subject of study. Moreover, it is by no means easy to determine in many cases what parts of the total “sorption” are due to adsorption, solid solution, or even chemical combination. McBain has emphasised the sensitiveness of the course of adsorption to the progressive removal of chemical heterogeneity from a porous surface. Some applications of the electric coherer to adsorption problems have been described in former communications; it may perhaps be appropriate to recall the main advantages that the method appears to possess over the more direct technique in common use; ( a ) the adsorption takes place on the non-porous and chemically homogeneous surface of a fine metal filament, that can be submitted to heat treatment electrically with great ease; ( b ) there is an immediate and direct test of the “bareness” of the surface, quite independently of the subsequent adsorption experiments; ( c ) from the nature of the technique only true surface films play any part in the measurements. The principal disadvantage is that the adsorbed amount is measured by the critical cohering voltage instead of directly, but this difficulty can be surmounted in the follow­ing way.

III. Researches on refraction-equivalents

1868 ◽  
Vol 16 ◽  
pp. 439-444 ◽  
Keyword(s):  
Refractive Index ◽  
Good Deal ◽  
Symbolic Language ◽  
Chemical Combination ◽  
The Subject ◽  
Condition Solution ◽  
Minus Unity

Since the paper of the Rev. T. Pelham Dale and myself “On the Refraction, Dispersion, and Sensitiveness of Liquids our researches have been continued from time to time, and a good deal of attention has been paid to the subject in Germany. The permanence of the specific refractive energy of a body, notwithstanding change of temperature, aggregate condition, solution, or even chemical combination, has been confirmed, and upon this has been built the doctrine of Refraction-equivalents. Our specific refractive energy is the refractive index of any substance minus unity, divided by the density; in symbolic language µ –1/ d . Professor Landolt’s “Refraction-equivalent” is the same multiplied by the chemical equivalent, or P µ –1/ d .

scholarly journals Magnetism and atomic structure.—II. The constitution of the hydrogen-palladium system and other similar systems

1922 ◽  
Vol 101 (710) ◽  
pp. 264-279 ◽  
Keyword(s):  
Diamagnetic Susceptibility ◽  
Molecular Form ◽  
Surface Adsorption ◽  
Palladium Black ◽  
Previous Knowledge ◽  
Complex Process ◽  
Surface Condensation ◽  
Chemical Combination ◽  
The Subject ◽  
Molecular Forces

The present work is a continuation of that published in ‘Phil. Trans., A, vol. 214, pp. 109-146 (1914); A, vol. 215, pp. 79-103 (1915); A, vol. 220, pp. 247-289 (1920); ‘Roy. Soc. Proc.,' A, vol. 95, p. 58 (1918), and A, vol. 98, p. 264 (1921). It was believed that a magnetic examination of the properties of palladium black which had been charged with hydrogen would enable us to decide which of the proposed constitutions is the correct one. If the hydrogen were in the atomic state and free , one might expect that the system would be more magnetic than uncharged palladium black, whether the assumed constitution of the hydrogen atom be that of Bohr or that proposed by the author. If the contained hydrogen were in the molecular form, either in the state of a gas or condensed to a liquid, since gaseous and liquid hydrogen are both diamagnetic, we should expect a diminution of the magnetic property of the system by a small amount, depending on the minute diamagnetic susceptibility of molecular hydrogen and the amount of gas occluded. Lastly, if the hydrogen enters into combination with the palladium, or is associated with the palladium so as to form a type of loose chemical compound, we should, in the light of previous knowledge of the effects of chemical combination on magnetic susceptibility, expect a change depending on the nature of the compound formed. It is impossible here to go into details regarding the vast amount of work which has been undertaken to solve the problem of gaseous occlusion. Reference is made to the General Discussion held by the Faraday Society on the subject. It will be convenient to summarise here the diverse views at present held as to the nature of the complex process of occlusion. These have been given by A. W. Porter under the following six heads:— (1) Chemical combination of the gas with the metal. (2) Simple solid solution, either separately or in conjunction with (1). (3) Two solid solutions in contiguous phases. (4) Solution accompanied by surface adsorption. (5) Surface condensation under molecular forces unaccompanied by solution. (6) Simple inclusion of the gas in the interstices of the metal.

Joining of SiC Ceramic with Ternary Carbide Ti3SiC2

2005 ◽  
Vol 475-479 ◽  
pp. 1255-1258 ◽  
Author(s):  
Hongying Dong ◽  
Wen Bo Han ◽  
Shu Jie Li
Keyword(s):  
Thermal Properties ◽  
Base Material ◽  
External Pressure ◽  
Weld Strength ◽  
Mechanical And Thermal Properties ◽  
Technological Parameters ◽  
Orthogonal Experiments ◽  
Ternary Carbide ◽  
Sic Ceramic ◽  
The Subject

The investigation on joining of SiC to SiC has been conducted for some years. It is essential that the mechanical and thermal properties of the joints should meet the requirements of engineering. In view of the fact that the ternary carbide Ti3SiC2 has shown unique mechanical and thermal properties, it is promising to join SiC to SiC using ternary carbide Ti3SiC2 as filler (welding compound), and this is the subject to deal with in this paper. The joining of SiC to SiC has been successfully realized by hot pressing reaction joining process using Ti3SiC2 powder as filler. The optimized technological parameters have been obtained by orthogonal experiments, under which the achieved weld strength is higher than that of the welding base material SiC ceramic. Ti3SiC2 is stable up to 1200oC in Ar atmosphere with an external pressure. At the joining temperatures of 1300～ 1600oC the main phases of the interface are Ti3SiC2, TiC and TiSi2. The mechanism of bonding at the interface is interdiffusion and chemical reaction.

scholarly journals II. On the organization of the fossil plants of the coal-measures.—Part III. Lycopodiaceæ

1872 ◽  
Vol 20 (130-138) ◽  
pp. 199-203
Keyword(s):  
Cellular Tissue ◽  
Igneous Rocks ◽  
Single Bundle ◽  
Epidermal Layer ◽  
Vascular Cylinder ◽  
Fossil Plants ◽  
Similar Series ◽  
The Subject ◽  
Short Time ◽  
Coal Measures

An outline of the subject of this memoir has already been published in the Proceedings in a letter to Dr. Sharpey. In a former memoir the author described the structure of a series of Lepidodendroid stems, apparently belonging to different genera and species. He now describes a very similar series, but all of which, there is strong reason for believing, belong to the same plant, of which the structure has varied at different stages of its growth. The specimens were obtained from some thin fossiliferous deposits discovered by Mr. G. Grieve of Burntisland, in Fifeshire, where they occur imbedded in Igneous rocks. The examples vary from the very youngest, half-developed twigs, not more than 1/12 of an inch in diameter to arborescent stems having a circumference of from two to three feet. The youngest twigs are composed of ordinary parenchyma, and the imperfectly developed leaves which clothe them externally have the same structure. In the interior of the twig there is a single bundle, consisting of a limited number of barred vessels. In the centre of the bundle there can always be detected a small amount of primitive cellular tissue, which is a rudimentary pith. As the twig expanded into a branch, this central pith enlarged by multiplication of its cells, and the vascular bundle in like manner increased in size through a corresponding increase in the number of its vessels. The latter structure thus became converted into the vascular cylinder, so common amongst Lepidodendroid plants, in transverse sections of which the vessels do not appear arranged in radiating series. Simulta­neously with these changes the thick parenchymatous outer layer becomes differentiated. At first but two layers can be distinguished—a thin inner one, in which the cells have square ends, and are disposed in irregular vertical columns, and a thicker outer one consisting of parenchyma, the same as the epidermal layer of the author’s preceding memoir. In a short time a third layer was developed between these two.

The Aylesford-Swarling Culture: The Problem of the Belgae reconsidered

1965 ◽  
Vol 31 ◽  
pp. 241-367 ◽  
Author(s):  
Ann Birchall
Keyword(s):  
Standard Work ◽  
Archaeological Material ◽  
Similar Series ◽  
History Of ◽  
La Tène ◽  
The Subject ◽  
La Tene

Until the discovery of the Aylesford urnfield seventy-five years ago, the Belgae were still no more than dramatis personae in Caesar's Gallic War. It was Sir Arthur Evans who first identified the users of the Aylesford cemetery with the invaders ex Belgio referred to by Caesar. Reginald Smith's publication of the Welwyn grave-groups (1912) and then Bushe-Fox's excavation of the Swarling urnfield (1925) were followed, in 1930, by Hawkes' and Dunning's account of the history of the British and Continental Belgic tribes, which has remained the standard work on the subject ever since.Thus, it has been accepted that the archaeological material of Aylesford-Swarling type represents the introduction of Belgic culture into Britain. Its continental origins were traced to northern Gaul, the area occupied by the historical Belgae, where a similar series of cremation burials of Late La Tène date is known. This continental series, thought to mark a change from what seemed to be the universal practice of inhumation as mode of burial to cremation, was interpreted as representative of a fusion of inhuming Galli with cremating Germani from across the Rhine. This fusion, leading to the formation of the Belgae, who, as Caesar records, boasted of their ‘Germanic’ origin, was thought to have taken place in the latter half of the 2nd century B.C. The date for the first Belgic invasion of Britain was put at about 75 B.C.

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