Long-period Changes Research Articles

Long-period Change in Mean Sea Level in Japan

Long-period Change in Mean Sea Level in Japan

Plastic deformation of polypropylene

In a wide range of drawing temperatures (20 to 150° C) and draw-ratiosλ (5 to 20) the axial long periodL T is a unique function of temperature. It is completely independent of the long period of the starting material which was varied within wide limits (125 to 350 A). The gradual transformation of the long period observed at small draw-ratio (λ between 1 and 5) from the valueL 0 of an undrawn sample to the limiting valueL T>L 0 of highly drawn polypropylene (λ ≥ 5) could be demonstrated on samples withL 0 larger thanL T. The change of long period is abrupt, indicating a discontinuous step in the transformation from the original microspherulitic into the fibre structure. These results may be interpreted in the same manner as in the case of polyethylene. During plastic deformation in the neck the lamellae are broken into small folded chain blocks which are then incorporated into the microfibrils, the basic building element of the fibre structure. The work of deformational forces must so mobilise the chains in the blocks that they get rearranged with a new long period, corresponding to the temperature of drawing.

Investigations of the structure of ethylene‐propylene and ethylene‐butene copolymer crystals using fuming nitric acid. Part III. The effects of nitric acid on the physical properties of single crystal mats of ethylene copolymers

AbstractThe structure of crystals of random ethylene‐propylene and ethylene‐butene copolymers has been investigated using fuming nitric acid. This paper is concerned with the effect of nitric acid on crystals grown from a series of copolymers. The weight losses and changes in long period, heats of fusion and unit cell spacings which result from acid treatment are reported. From these results and using the results reported in the earlier papers of this series it is concluded that crystals grown from both ethylene‐propylene and ethylene‐butene copolymers are very similar in structure to linear polyethylene single crystals apart from the fact that branches are contained within the crystalline cores of the copolymer crystals. It is shown that there are some differences between the way that ethylene‐butene and ethylenepropylene crystals are attacked by nitric acid, and a possible reason for this is suggested.

Reversible long-period change during the annealing of crystalline polymers

Abstract A large reversible change in small-angle X-ray diffraction spacing and intensity in both bulk and drawn polyoxymethylene is found for samples carried through a heating and cooling cycle. The diffraction measurements were made at the annealing temperatures. The reversible changes are in addition to the more usual irreversible changes found during annealing experiments in which the scattering is measured at room temperature. Upon recycling the same sample, the changes can be almost completely reversible. Similar reversible changes are not observed for polyoxymethylene single crystals but are observed for drawn polyethylene terephthalate and nylon 6.

Statistical evidence indicating no long-term climatic change in the deep waters of the north and south Pacific oceans

No inference of climatic change appears to be warranted from an analysis of temperature and salinity values below 100 meters at 189 oceanographic stations in the North and South Pacific oceans. Data collected in the period 1929–1932 by the Carnegie, Dana, Scoresby, Discovery II, and International Fisheries expeditions were used as reference stations. These reference stations were paired with data collected between 1824 and 1958. Fifty percent of the stations were within 60 nautical miles of their reference stations, 30 per cent were between 60 and 120 nautical miles, and 20 per cent were between 120 and 568 nautical miles. The stations that were more than 120 nautical miles from their reference stations were included in order to obtain additional deep-station values, but they were limited to the same water mass as the reference stations. The analysis showed large random individual differences in both fields down to 1000 meters, and smaller but significant anomalies in several instances between 1000 and 5000 meters. For the data grouped by years or by water mass, scattered significant differences were observed at all levels and in all groups. Much larger samples are needed to separate statistically the short-period variability and the instrumental, processing, and interpolation errors from long-period change in deep waters.

Secondary Oscillations in an Equatorial Atlantic Deep-Sea Core

PRIMARY oscillations, corresponding to long-period changes in temperature in the upper layer of the sea, have been reported in long cores from Equatorial and North Atlantic, the Caribbean and Mediterranean Seas1–3. These changes, apparently the equivalent of glacial and interglacial periods, have been followed by: oxygen-18/oxygen-16 measurements on selected species of Foraminifera which deposit their tests in the upper layer of the sea; determining the proportions of planktonic Foraminifera characteristic of warm, temperate and cool waters; carbonate analyses and grain size determinations.

The Radial Velocity of Delta Cephel.

view Abstract Citations (35) References (12) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Radial Velocity of Delta Cephel. Shane, W. W. Abstract Twenty-seven observations of Cephei made in 1950 with the Mills spectrograph are combined with observations obtained in 1907 and 1923 in order to determine a definitive velocity-curve. The following conclusions are drawn: (1) there is no evidence of any long-period change in the mean velocity; (2) there is no evidence of change in the form of the velocity-curve; (3) the mean velocity is - 16.1 + 0.2 km/sec; the velocity range is 39.4 km/sec. An attempt is made to ascribe the velocities measured to some identifiable level in the stellar atmosphere. Publication: The Astrophysical Journal Pub Date: May 1958 DOI: 10.1086/146490 Bibcode: 1958ApJ...127..573S full text sources ADS | data products SIMBAD (13)

A long-period change in radio-frequency radiation from the "quiet" sun at decimeter wave-lengths.

A Long-Period Change in Radio-Frequency Radiation from the ‘Quiet’ Sun at Decimetre Wave-Lengths

LITTORAL PROCESSES IN LAKES

The purpose of this paper is to present the general topic of lake processes to an engineering audience from a geological point of view. It is apparent that the shores of larger lakes present many problems in common with the sea coast, but the absence of tides, and of first-rank storms, means that geological processes are less marked, and structures may in general be smaller. In contrast to many coastal areas, the Great Lakes probably have less consolidated materials in their banks and bluffs, inasmuch as the basins lie mainly in glacial deposits. Hence rates of erosion may be much greater than on harder coastal rocks. The effect of long-period changes in level also introduce problems of selecting distances above and below lake datum in structures, to allow for the more shoreward wave action during times of high levels. The much leaner shore drift along lakes as compared to the oceans also means that problems of beach development and maintenance may be more difficult to solve. Greater reliance on imported sand in closed systems seems to be the trend in some larger communities where the demand for recreational beaches is great.

The Present State of the Newfoundland Seal Fishery

THE Newfoundland seal fishery, while of considerable antiquity, is neither the oldest nor the most important industry of the country. Nevertheless, it brings some two or three hundred thousand dollars into the country just when they will do most good, at the end of the winter when the fishermen are preparing to fit themselves out for the summer's cod fishery. The seal fishery used to be much larger and more important financially than it is now, as will be shown later, and there is considerable conflict of opinion as to whether it has been suffering a merely temporary decline or is in serious danger of dying out. After a bad season, one captain may utter grave warnings that the seals are being exterminated, while another will maintain that the seals are as numerous as ever, but have been hard to come by. In view of these differences among experts, it seemed worth while to examine the records of the sealing fleet as far back as possible, to see if this would give any indication of long-period changes in the success of the fishery. Fortunately, the records of the steam sealing fleet are remarkably complete back to the first use of steam sealers in 1863. Their compilation has been the patient labour of Mr Levi Chafe of St John's; they are published in his Sealing Book (of which a copy is available in the Bureau of Animal Population at Oxford) and are added to year by year. This book is a mine of information about the sealing industry and has formed the principal basis for the present paper. For information concerning the habits of the seals off Newfoundland I am indebted partly to Mr W. A. Munn's introduction to the second (1923) edition of the Sealing Book, but chiefly to Nansen's Hunting and Adventure in the Arctic (1925). The present paper is no more than a review of known facts, and is an attempt to clarify the prevailing uncertainty as to the state of the fishery. In any one year, as will be shown below, the success of the fishery depends on several factors, such as the type of ship used, the thickness of the ice, the weather conditions and, above all, on the number of men fishing. In the long run, the answer seems to be that at the present time and at the present rate of fishing the seals are a little more than holding their own.

The Sensitivity of Taxes to Fluctuations of Trade

THE SUBJECT of the of the yield of various types of taxes to the movements of the trade is of great practical importance; but it has been almost completely overlooked in the standard English works on public finance'-perhaps because, until recently, the science of public finance has been built almost entirely upon a framework of theories of a static or evenly progressive economic system. It therefore seems worth while to outline a theory of the subject, and to try to obtain some simple statistical measurements. The first problem is to discover a satisfactory standard against which to measure the cycle sensitivity of taxes, which can be applied at different times and in different countries. Since money income is the ultimate source from which all taxes must be paid, it seems desirable to measure fluctuations in the yield of particular taxes against fluctuations in the total of national social income,2 wherever satisfactory figures for these are available. It is, of course, previously necessary.to eliminate the effects upon the yield of alterations in the rates or basis of the tax, which have taken place during the period under review. We can then say that the of any tax, in any year, or in any phase of the trade cycle, is measured by the formula Percentage Change in Yield Percentage Change in National Social Income This method eliminates from the result the effects of general price movements, and of the expansion or contraction of population; though of course it leaves untouched the effects of long-period changes of relative demand and of the distribution of wealth, in so far as these are independent of the trade cycle. Satisfactory elimination

Irregular Long-period Changes in Level

AT the Portsmouth meeting of the British Association Mr. F. Napier Denison contributed a paper on changes in level observed with a horizontal pendulum at Victoria, B.C. Observations commenced in January, 1899, and extended over the next eleven years. For the most part these refer to changes in level in an east-west direction. Like observers in other parts of the world, he found diurnal, annual, and other changes, all of which can be referred to epigenic influences.

The Variable Star η Aquilæ1

THIS essay contains a full discussion of all the available observations of a remarkable variable star, the fluctuation of whose light presents many features the explanation of which is still beset with much difficulty. Of the 12,000 recorded comparisons of the relative brightness of η Aquilæ and neighbouring stars, no less than 7147 are due to the indefatigable perseverance of Julius Schmidt, who for the last twenty years of his life (1859-1879) was director of the observatory at Athens. Taking advantage of the preponderance of Schmidt's records over those of all other observers, the author first, investigated the variations of the star's light as shown by these alone, and then examined in how far the results thus obtained were confirmed by the labours of other observers. The discussion of Schmidt's observations was complicated by the circumstance that in the majority of cases he only used two comparison stars, β and ι Aquilæ, one of which there was great reason to believe was itself variable. From the 1700 occasions on which both stars were used, Dr. Lockyer found ι to vary 1˙7 grades of Schmidt's scale with a period of about thirty-five years. Associated with this long-period change, the relative brightness of ι was shown to be subject to an annual variability of about one grade, which is clearly traced to the influence of the hour angle at which the stars were compared. This apparent annual variation is, therefore, identical with the “position error” noted by many observers of variable stars, and which has lately been investigated so thoroughly by Mr. Roberts, of Lovedale, South Africa. Schmidt's observations, freed from both the above variations as well as from the slight aberration error due to the changing position of the earth iaits orbit, were all reduced to the meridian of Bonn. Owing to the general sparseness of the data, it was necessary to combine the observations of 100 periods, or about two years, into a group represented by a single curve. This was effected with the help of a provisional mean period and date of minimum for which Argelander's values of 7d. 4˙23444h. and 1848, mag. 18d. 6˙4333h. M.T. at Bonn were adopted, the date being that of epoch 400. To further facilitate the construction of the curve the mean brightness in each 6-hour interval of the period was set down for each group, together with the corresponding time and the number of observations. In this way the whole of the materials collected by Schmidt from 1844 to 1879, and tnus covering eighteen groups of 100 periods each, are expressed in tabular form on p. 21 of Dr. Lockyer's dissertation. The numbers for each period were then plotted on millimetre paper; tentative and afterwards definite curves representing the fluctuations of the star's light were drawn through the points thus obtained. The resulting eighteen curves representing Schmidt's observations are reproduced one above the other on a small but distinct scale on Plate I., each curve being prolonged by about one-third of the period to bring out the form of the minimum. A study of these curves shows that Argelander's period cannot, at present, be improved on as a mean value. The time of Argelander's epoch 400 is, however, shown to be too early by oan interval which the author fixes at 3˙2655 hours. The curves also show conclusively that the epoch of maximum oscillates to and fro to the extent of five hours on either side with a period comprising 400 maxima. In the same way the minima are subject to an oscillation of about three hours in approximately 2400 periods. The combined effect of these variations causes the light-period to “vary between 7d. 4h. 14m. 40s. and 7d. 4h. 13m. 28s. also in 2400 periods. Superposed on the main light curve are four subordinate undulations, of which more hereafter.