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A graph paper on which a Gaussian function of unit amplitude appears as a straight line was produced in an attempt to devise a method which would combine the obvious advantages of a linear presentation with the improved definition and convenience of a differential plot. A semilogarithmic plot of the linear differential pulseheight spectrum of 622 kev gamma ray from a Cs137 source is given as an example of the technique. The method requires only the data points from the multichannel analyzer and an estimate of the maximum height of the photopeak above background. Gaussian plots proved convenient checks on instrumental reliability; amplifier nonlinearity or drift cause noticeable deviations from linearity. (P.C.H.)

Publisher Summary This chapter presents experiments on deformations of paper in stacks, in which sheets were conditioned at a fixed humidity and then printed with a screen line plate by means of a Vandercook proof press. The prints were stacked progressively during printing. The stack was exposed to another humidity for a time and then, a second color was printed upon the first one, from the same plate. From the interference of the two line patterns, it was possible to measure deformation of the paper. Every sheet was measured and the results for an offset paper, a conventional coated paper, and a machine-coated paper are presented in the chapter. The change in dimension is given on the abscissa in units of 0.1 mm/m. The trials were made on three papers: (1) an offset paper, (2) a conventional coated paper, and (3) a machine-coated paper. The results show that the deformation was greater in the transverse direction than in the longitudinal direction and the deformations were not the same whether the transverse direction or the longitudinal direction was parallel to the cylinder axis; this effect shows that the press has a laminating action.

I have studied the visco-elastic properties of paper by vibrating reed method at super low frequency range and I measured, Youngs modulus internal frictional coefficient (viscosity).Youngs modulus and viscosity varies by direction in hand made paper, but Youngs modulus is independent of frequency in the range of low frequency. It reduces as increasing frequency. This viscosity is so-called apparent viscosity so, I will convert it true viscosity by next method let us shearing stressv2lv : frequency, l : length.rate of shear v2l/η I plot v2l, v2l/η I obtain consistency curve.I will regard consistency curve as two kinds straight line.I think this straight line means the true viscosity. Let us those viscosities ηHF (Viscosity at high frequency) ηLF (Viscosity at low frequency). Reasonable solution of these two kinds viscosity ηHEηLFis the problem of future.Youngs modulusEand ηHF, ηLFincrease as reducing its freeness in hand made paper.but increasing process changes by pulp sorts.

It is established that when a uniform film of liquid is pressed against the surface of a material through rolling, the depth of the deepest part of surface which can be coated is equal to the initial thickness of the film. The total coated area, which may be determined by the change in diffuse reflectance of the material, varies with film thickness but is shown to be independent of the rheological properties of the liquid. These observations are utilized in a treatment developed to determine the topographical structure of a surface. Results show that the surface structure of paper can be described by the Gaussian distribution of the logarithm of depression. The surface structure is sensitive to both load and velocity of rolling, but tends to become stabilized at high load or low velocity. It is suggested that the maximum of the pressure distribution in rolling matters most, but its effect may be complicated by the varying number of stress-bearing sites on the surface and by the interaction between them and their neighbours. The effect of velocity is attributed primarily to the viscoelastic nature of paper and secondarily to the number of stress-bearing sites.

The paper describes a series of experiments that were conducted on a compressor blade of conventional geometry, in a low-speed research compressor, to determine the effect of Reynolds number on the performance of (1) an isolated rotor blade row when the free-stream turbulence is low, (2) the isolated rotor at a higher level of turbulence, and (3) the rotor row when unsteadiness is introduced by a set of inlet guide vanes of zero camber and zero stagger. In each case the axial velocity ratio at mid-span was measured and tests were carried out under similar conditions on a two-dimensional cascade of blades using a wind tunnel with porous side walls. The compressor results indicate that there are significant Reynolds number effects under these conditions, and the comparison with the cascade results demonstrates that there is a difference in performance between the rotating row and the cascade.

This paper constitutes a review of the research work completed at the Computing Center of the USSR Academy of Sciences dealing with the theory of optimal orbit transfers for space vehicles powered by low-thrust rocket engines.

A. E. Kennelly: Turning to the paper by Dawes and Hoover, it seems to me that the great force of that contribution lies in the fact that a bridge has been developed which employs a vibration galvanometer, with all the delicacy and precision that the vibration galvanometer affords, so that instead of having to employ a relatively great length of cable dielectric for test, it is sufficient to have only, say, a couple of meters, provided that the particular couple of meters shall represent fairly well, the whole length of a cable under consideration.

This paper describes some of the results obtained from a series of experiments on internally air-cooled turbine nozzle and rotor blades. These were formed by an extrusion process and had, respectively, sixteen and thirteen cooling passages of approximately elliptical cross-section. The cooling characteristics of both types of blade were measured in an experimental high-temperature turbine and further experiments were conducted in cascade tunnels. Some of the cascade experiments on the rotor blade were conducted at comparatively high Reynolds numbers and showed, in accordance with predictions, the extent to which chordwise non-uniformities in blade temperature become larger as Reynolds number is increased. Other experiments were conducted with the turbine to determine the effects on aerodynamic performance of discharging spent cooling air into the main gas stream. The results showed good agreement with predictions based on a simple flow model, and in particular indicated that flow separation, with its associated losses, did not occur. Finally the results of an endurance test are presented, together with a brief description of the way in which thermal plus centrifugal stress patterns can be redistributed by creep in non-uniformly cooled blades. Brief mention is made of those fields of research which require further attention, namely an investigation of the factors governing the local values of heat-transfer coefficient on the external surface of turbine blades and the testing of the assumptions used in calculating stresses in cooled blades.

To prevent or minimize the erosion of the last row rotor blades in large high-speed steam turbines it has been proposed to remove the film of water on the surfaces of the last row stator blades before it reaches the trailing edges and is swept off by the steam drag into the path of the rotor blades. The paper describes experiments with a cascade of hollow stator blades with various dispositions of slots providing communication from the blade surfaces to the hollow cavity. The same cascade was used in turn with three different wet air tunnels, the experiments thus covering a wide range of Mach number and Reynolds number. With suitably disposed slots, and bleeding a very small proportion of the working fluid, about 90 per cent of the deleterious water can be removed, thus preventing it from striking the moving blades.

As the size of steam turbo-alternators has so rapidly increased, the diameter and surface speed of the journal bearings are such as to cause the oil film to become at least partially turbulent. Little information is available on the performance of large bearings operating in the transition and turbulent regimes and it became necessary to undertake a research programme on a full-size test rig. The apparatus was designed so that bearings of various geometries could be tested under both static and dynamic loads. This paper describes some of the static load tests on a 24-in diameter by 18-in long bearing and is confined to describing the factors influencing the transition from laminar to turbulent flow in the film. An analysis of the results indicates that even at low speeds there is a dependence on the Reynolds number and it is suggested that the inertia of the oil film has a pronounced influence. The transition to turbulence is delayed by axial flow and shaft eccentricity, but is ultimately precipitated by the effect of eddies in the oil supply channels and in the grooving.

This paper describes details of a solution to the finite journal bearing problem, including the effects of elastic distortions in the bearing liner. Solutions for the particular case of a bearing of length to diameter ratio of 1, outside to inside diameter ratio of 1·3, and Poisson's ratio of 0·4 have been obtained and the results are compared with experimental results obtained with a Delrin plastic bearing. Good agreement between theory and experiment has been obtained. The theory, which is applicable to soft shell bearings supported in a rigid housing, predicts that: (1) the ratio of the peak pressure to the average pressure is reduced; (2) the bearing stiffness is reduced; (3) the minimum film thickness for a given load is reduced by elastic distortions at eccentricity ratios less than unity; and (4) the friction is reduced.

The effects are considered of base circle eccentricity, pitch error, dropped tooth, tooth bending under load, and of involute error on the transmission errors of gears. Measurements accurate to ± 1/4 μm show that adjacent pitch errors are frequently randomly distributed. When subject to Fourier analysis, they can give rise to unexpected harmonics both in the errors of a gear and the noise produced by it. A cause of ‘phantom’ gear noise is suggested.

Since the Chartered Engineer can make a major contribution to all the most important problems of the regulation of civilization, it follows that he has a tremendous responsibility to society to study these problems and devote as much as possible of his skill in original engineering to their solution. It is suggested that in the future every engineer will take a Hippocratic oath on becoming chartered. It also follows that the C.E.I. must have, in the future, a very great responsibility for working out national and international policy on engineering developments. There are a number of major problems which urgently need consideration by qualified engineers on a national basis. The Chartered Engineer of the future will be trained for this responsibility by developing his natural inventiveness and showing him how to make the inventive leap by teaching him the application of the laws of science to inventive problems and by teaching the knowledge of reality through the hands (creative design). The engineer will be trained on how to think about and understand his social responsibility. The C.E.I. will take a number of active steps to upgrade the status of engineering in the schools, including the setting up of a special grade of Fellowship. The Chartered Engineer of the future will decide what to invent and develop by his understanding both of the needs of humanity and their economic solution.

Two mistakes have been found in previously published papers about the electron beam monitor system of the NBS Linac. They invalidate the previously proposed explanation of the change in the measured Faraday cup error when vacuum foils are introduced into the beam line. When these mistakes are corrected, it is found that the generation of secondary electron by Moller scatter in the vacuum foils accounts for only about one third of the observed change, rather than all of it, as originally claimed. Additional experiments at 50 MeV have shown that the observed change is a non-linear function of foil thickness, and that the beam transmitted by the foils includes electrons with energies as small as 0.3 MeV. Electrons with this low an energy could not have been generated by Moller scattering and must be the product of multiple processes in the foils.

Shooting methods are used to analyze rectangular waveguides containing inhomogeneous lossy dielectrics. The technique obtains the electromagnetic fields inside the waveguide by solving Maxwell's equations using trial and error procedures to match the boundary conditions at the conducting waveguide surface. Dispersion and attenuation curves are obtained which show how continuous dielectric inhomogeneities and losses affect the transmission characteristics of these waveguides.

Measurements on MIC dielectrics have been made by applying the theory of resonant cavities to either wholly or partly metallized substrates. Two different schemes of coupling are employed, depending upon the metallization. Errors occur in the derived value of /spl epsi/, due to the coupling, and are of opposite sense for the two methods discussed. They may be averaged to improve the overall measurement precision (0.5 percent).

This paper reports a portion of findings obtained from a continuing study of CRC (continuously reinforced concrete) pavements in Indiana. Results of an earlier statewide condition survey showed that subbase type, methods of fabrication and placement of steel reinforcement, concrete slump and traffic were significant contributors to CRC pavement performance. It was indicated that method of paving (slipformed vs side-formed) had little effect on pavement performance, while depressed steel resulted in better pavement condition than steel pre-set on chairs. Based on these results, a field investigation of CRC pavements was conducted. The purpose of this study was to evaluate, by means of physical tests, parameters that were found to contribute significantly to CRCP (continuously reinforced concrete pavement) performance in the condition survey. The results reported in this paper were obtained from a comparative statistical analysis of properties of failed locations with good locations within test sections showing poor performance. The analysis was based on data obtained from 15 CRCP test sections showing significant distress as indicated by a breakup or a patch. Test locations in good condition had subbases with higher stability as evaluated by a static penetrometer test. Pavement failures were observed to be correlated with relatively low bulk density and modulus of elasticity of concrete. No significant difference In splitting tensile strength of concrete was Indicated between good and failed locations. Relative to uniformity of concrete properties above and below the steel reinforcement, no significant difference was shown In the analysis. Higher pavement deflections, wider crack widths and non-uniform crack patterns were associated with failed pavement condition.

Two sources of error in the treatment of data in the recent paper by D. Hardie and R. N. Parkins are discussed. The errors are serious enough to cast doubt on the conclusions contained in the paper.

Petschek [1963] has computed a value of 2·10−4 for the fission β counting efficiency of the lead-shielded Anton Geiger counter in the Injun satellite. Since the efficiency of heavily shielded counters to nonpenetrating electrons is of importance in the interpretation of satellite radiation measurements [Van Allen et al., 1963; Hess, 1963], I wish to draw attention to several errors in Petschek's paper. I wish also to comment briefly on the thick target electron bremsstrahlung process, as it is relevant to the problem of space radiation hazards and of the interpretation of auroral X-ray measurements as well as to the efficiency of shielded Geiger counters.

An independent search through the Heaviside Collection of the Institution of Electrical Engineers for the material discussed in Heaviside's ‘posthumous papers’ is reported.

A brief summary is given of the paper by Stiles. The line-element suggested by Stiles is shown to be the sum of the squares of total differentials of three magnitudes. Therefore, the corresponding color threefold is Euclidean. For the same reason, the line-element originally proposed by Helmholtz also defined a Euclidean color space. The customary parameters of colorimetry correspond to curvilinear coordinates in the color space of both Helmholtz and Stiles. In both of those spaces, constant luminosity is represented by curved surfaces. The forms of the line-elements of both Helmholtz and Stiles imply that geodesics, representing series of colors which exhibit the least number of just-perceptible differences between any two colors, are straight lines in the Euclidean spaces defined by those line-elements. They also imply that ordinary length measured along these lines is proportional to the number of just-perceptible differences between the colors represented by the terminal points. No direct tests of these implications are known. MacAdam’s data on the discrimination of equiluminous colors determine a surface of constant luminosity in the color discrimination space for at least one observer (PGN). This surface exhibits such severe (and irreducible) curvature that the straight lines drawn between most pairs of considerably different equiluminous colors are, at their midpoints, far from the surface of constant luminosity. The line-elements of both Stiles and Helmholtz, therefore, imply that the series of colors exhibiting the least number of just-perceptible differences between two equiluminous colors includes many colors of very different luminosity. Although no observational tests are known, it seems unreasonable to expect that considerable departures from the common luminosity of the terminal colors will reduce the number of differences perceptible in any series between them. Attention is called to the criterion of probability of errors in color matching as an alternative to just-perceptible differences for investigations of visual sensitivities to color differences. This concept leads to a definition of the line-element independently of any assumption of the applicability to color discrimination of Fechner’s law or its modifications.

The rate of energy flux in an ultrasonic beam, propagating in a fluid medium, may be expressed for a single frequency and longitudinal oscillation by Eφ = 1T ∫ 0T A pudt, where T is the period of oscillations, A the cross section of the beam, p the instantaneous value of pressure oscillations, and u represents particle velocities causing the pressure oscillations. This is the basic equation with which, at the turn of the century, Lord Rayleigh calculated acoustic intensities in gases. Almost half a century later, Langevin was first to measure ultrasonic intensities in liquids by evaluating radiation pressures created by these intensities. A simple theoretical basis to these evaluations was already established two decades prior to his experiments. Further theories were later developed to express more closely the relationship between the radiation pressure and sonic intensities. The complexity of wave propagation phenomena in real media, however, has been preventive in establishing an exact theory, especial...

This spectrograph records upon sheets of photographic paper 20×30 inches in size, spectra lying in the range between 18μ and 200μ. Of this range, 9μ may be spread over a single record, or as much as 100μ may be covered, depending upon the gratings and the adjustments used. The spectrograph is a vacuum instrument of high resolving power, being capable of separating sharp lines somewhat closer than 0.5 cm−1 apart. Detailed drawings of its construction together with several records are shown and described. The recorded galvanometer deflections are usually adjusted to lie between 100 and 300 mm.

A digitally recording seismograph station has been installed to record and study earth noise in the frequency range of 0.01 to 1 cps. The system is capable of recording four channels of information plus time on paper tape at sample rates of up to three times per second with a dynamic range of 90 db. Preliminary analyses of the digital records show that the spectral peak between 0.1 and 0.2 cps exhibits properties consistent with Rayleigh waves arriving from the southwest mixed with isotropic noise.

X‐ray line profiles are measured fully automatically by means of a preprogrammed step scan. The intensity data are taken by means of the fixed count method and punched into paper tape by an electronic clock. The evaluation of the intensity data and the Fourier analysis of the line profiles is performed on an IBM 1620 computer.

In October 1971, the Council of the European Community ratified a directive on units and measurements (EEC, 1971) which provides for the exclusive use by January 1, 1978 of a prescribed system of metric units. This system is firmly based on the International System (SI) as agreed by the General Conference of Weights and Measures, and its strict application could result in the eventual abandonment of the “special” radiological units, the roentgen, the rad and the curie. Indeed steps in this direction have already been taken in two European countries. In a recent Government White Paper (Metrication, Cmnd 4880, 1972), it is clear that the EEC directive would apply to the United Kingdom as a member, though special arrangements have been negotiated to retain certain imperial units until December 31, 1979, or longer in some cases. The British Committee on Radiation Units and Measurements (BCRU) has already discussed this matter and is concerned that wider consideration should now be given to the concepts involv...

At the present time, seismological and many other geophysical processes are recorded mainly by the action of light on a photographic paper or plate, using a mirror galvanometer driven by the emf from a seismograph or other transducer. This method gives accurate and detailed records, even of weak processes. Its main defect is the large, unproductive expenditure of photographic materials.

IT may be allowed to me to remark that the error mentioned on pp. 172 and 223 of NATURE has its origin really in Helmholtz's renowned paper (“Ueber die Erhaltungder Kraft,” 1847, p. 67), and that it thence found its way into most of the textbooks on electricity. It has sometimes been detected and hinted at; for the first time, I believe, in C. Neumann's paper published in the Ber. d. k. sachs. Ges. d. Wiss, at Leipzig (1871), “Elektrodynamische Untersuchungen mit besonderer Rucksicht auf das Princip der Energie.” There we find (p. 436) the formula—which is identical with the equation of energy given in NATURE, p. 223, if we put—

A direct-reading, self-recording densitometer with single thermocouple and low-resistance D’Arsonval galvanometer has been constructed and used to measure the relative opacities of the photographic images of the lines in ordinary spectra and in X-ray powder photographs. By suitable gearing to an electric motor the photographic negative is given a slow motion at right angles to a beam of light passing through a horizontal lens system; and at the same time a drum carrying photographic paper, on which a spot of light from the galvanometer is focused, is caused by the same motor to rotate at such a rate that a certain distance on the drum corresponds to a certain distance on the negative. A permanent record of the true distribution of opacities is thus obtained, since the deflections of the galvanometer are inversely proportional to the opacities on the negative.Preliminary experiments show that the apparatus is dead beat and quick in response; and that it is sensitive, stable, and accurate.

A historical review of pioneer use of x-ray radiography in Great Britain is given. (H.H.D.)

Robertson and Fox in their fundamental memoir have published a comprehensive account of the precautions necessary for obtaining reliable results with a prism spectrometer in the infra-red between 1 and 17 μ. The authors feel, however, that some advantage to other workers may accrue if they in turn outline their own particular difficulties with the manner of their resolution. it may be stated at once that it is how possible to make scale readings to an accuracy of 1 mm. during the day , with a galvanometer sensitivity of 10 -10 to 10 -11 amp. per millimetre deflection at 1 metre distance. If it is realised that the work is carried out on the top floor of the Chemistry Department of this Institution, in a building which houses some dozen electrical generators and a large liquid air plant with a stream of heavy bus traffic 10 yards from the building and a tube railway at 100 yards, it will be seen that the usual experimental difficulties have been completely overcome. Preliminary experiments were made in a constant temperature room in the basement; the humidity was high and had a deleterious effect on the rocksalt portions of the apparatus, whilst the discomfort of night work in such a room was extreme. It has consequently decided to re-approach the problem from the beginning, but not before trials had shown that where the motion of the building as a whole is small, comparatively simple expedients serve to eliminate most of the mechanical disturbance. This was cut out by placing the galvanometer with its Paschen shields (total weight about 250 lb.) on a large block of wood supported by for pairs of inverted small porcelain crucibles placed at the corners. Eight of the thinnest available crucibles were selected; the two in a pair were placed one on top of the other and separated by a small piece of 5-ply wood and a few pieces of filter paper. If the galvanometer and shields are not too heavy, the replacement of the rubbershock absorber in the ordinary anti-vibration spider by a crucible and one or two layers of filter paper was found very efficient.

In the development of the study of crystals by X-rays the methods used divide themselves naturally into four types : the Bragg Ionisation Spectrometer method, the Laue method, the Powder method of Debye and Scherrer, and the Rotating Crystal method of Rinne, Schiebold and Polyani. The techniques of the first three of these methods are fully explained in such books as ‘ X-Rays and Crystal Structure,’ by W. H. and W. L. Bragg, ‘ The Structure of Crystals,’ by Wyckoff, and ‘ Krystalle und Rontgenstrahlen,’ by Ewald, as well as in original papers. On the other hand, the rotation method is only slightly touched on in these works, the literature is scattered in a great number of papers, and the technique has not so far been described at any length in a convenient form. Particularly in English, references to it are scanty. In this paper the author has tried to give a concise account of the method, together with various types of charts and tables as it is used in the Davy Faraday Laboratory. The methods described differ in certain respects from those used on the Continent,* but they have been found to be rapid and sufficiently accurate.