ALBERT

Notes: The principle of the mise-á-la-masse method is to earth one current electrode of a pair in a conducting mineral show (in a borehole, in an outcrop etc.) and measure the resulting distribution of electric potentials. The distribution will, to some extent, reflect the geometry of the ore mass of which the mineral show forms a part.In a mise-á-la-masse survey of a lead-zinc deposit in Central Sweden electric potentials were measured on the surface of the ground as well as in some 25 drillholes, in either case with earthings (successively) in three different parts of the irregular ore deposit. Besides this, measurements were made in drillholes with earthings in two further drillholes.Geologic correlation between the drillholes is difficult in the present case on account of the irregular geometry of the ore deposit. However, the mise-á-la-masse measurements clearly showed the dip and the pitch of the ore body, established connections between the different ore widths encountered in the various holes, and yielded information about the shape of the ore mass.In particular, the survey showed that the ore lenses must be crescent-shaped rather than tabular, and the dip was indicated to be westerly, instead of easterly as originally presumed.Three-dimensional models of equipotential surfaces were constructed from the observed drillhole and surface potentials (using transparent plastic sheets and thin copper wire) and these helped to elucidate the mass geometry further.The surface and underground potential data collected in the present case should be of nterest to geophysicists working on analytic continuation problems.

Notes: The author comments the techniques and methods used in continuous seismic profiling by the Monaco Oceanographic Museum during the last five years.Pinger probe give informations on the Mud layering and thickness. On the shelf or in abyssal plains, boomer and sparker are employed and allow to rise various geological conclusions. South coast of France, continental shelf in the Gulf of Lion, abyssal plain of the Ligurian Sea and Lake of Geneva are the areas concerned to with the results.

Notes: The author proposes the parameter Δ2/ΔT1 for possible application in aeromagnetic surveying making use of already available gradiometer systems equipped with sensors separated vertically.

Notes: Geophysical field equipment has undergone rapid changes in the past decade; from simple AGC amplifiers and galvo cameras to binary gain switching amplifiers and digital recorders, all in an attempt to keep pace with the new geophysical interpretive methods developed, and the growing acceptance of the terminology, methods, and philosophy of communication theory.The additional tools of the digital recorder and digital computer make it possible to utilize these new techniques in geophysical processing. Accomplishing these new techniques demands severe requirements on the digital field recording process in handling the decreasing energy return from the seismometer, and to fully realize the capabilities of digital techniques in reducing data. Simple automatic gain control may be used. However, in the more sophisticated interpretive methods, such as autoregression and deconvolution, it is necessary to reconstruct the actual energy levels in the computer. Recording the control signal used in master AGC or programmed gain control may prove satisfactory; however the accuracy of control versus gain is limited to I% for such analog instrumentation.To utilize the computer to its fullest extent, and to accurately perform these new techniques, requires an accuracy of I% or better. This accuracy is obtainable by using a step gain control where the gain is increased by fixed steps in which each step represents a gain in amplification by a constant factor. The accuracy in this case can be made dependent only on the tolerance of resistors used as attenuators or feedback elements. Preferably the constant factor of gain steps should be a number easily handled by the computer. By using 6 db steps it becomes a simple matter to shift binary numbers, such as multiplying or dividing by 10 in the decimal system.The requirements or parameters for such an amplifier system, and the elements of the amplifier necessary to achieve these requirements are presented.

Notes: Consideration is given to the use of a configuration of four electrodes set in a square array for resistivity measurements.It is found that, by passing current successively between different pairs of electrodes, an apparent resistivity can be determined which is both more sensitive to the position of the array centre and less dependent on orientation than the measures usually obtained with colinear arrays of electrodes. At the same time the observations made enable the degree of the departure of local conditions from conditions of lateral homogeneity to be assessed.Theoretical and practical examples of the use of this electrode system are given and the use of the system both as a tool in mapping and in depth investigations is considered.It is shown that provided electrode spacings are suitably arranged the results of a probe carried out using the square array can be interpreted by conventional methods.The system is shown to have particular advantages in the investigation of lateral resistivity variations and the reduced dependence on orientation makes possible the recasting of interpretation data in an orientationally invariant form with a consequent drastic reduction in the number of type curves required for a particular problem.

Notes: A large self-potential anomaly was outlined in 1963–64 at Tantahuatay near Hualgayoc in the Andes of northern Peru. Peak value recorded was–1842 millivolts–thus making it one of the strongest, or perhaps the strongest, SP anomaly ever measured. A lack of detailed geological data precludes the formulation of an adequate explanation for the Tantahuatay anomaly, but geological and mineralogical similarities with the well-documented Venencocha anomaly near Cerro de Pasco, Peru (Kruger and Lacy, 1949), suggest that the anomaly arises from sulfuric acid associated with the mineral alunite. The anomaly obviously cannot be explained by the half-cell mechanism of Sato and Mooney (1960), who place a limit of 700 millivolts on self-potential anomalies over sulfide bodies. Further study of the Tantahuatay anomaly would be of interest in understanding self-potential mechanisms in general.

Notes: Book review in this articleF. S. Grant and G. F. West, Interpretation Theory in Applied Geophysics, McGraw-Hill Comp., New York, 1965, 583 pp., price $ 17.50.Archaeo-Physica. Technische und naturwissenschaftliche Beiträge zur Feldarchäologie. Mit Beitragen von E. Le Borgne, I. Scollar, J. D. Mudie, J. Görier, H.-J. Appel, G. Strunk-Lichtenberg, Böhlau Verlag, Köln, Graz, 1965, 202 pp., 124 fig.H. Takeuchi, Theory of the Earth's Interior, Blaisdell Publishing Company, Waltham (Mass.), Toronto, London, 1966, 131 pp.G. D. Garland, The Earth's Shape and Gravity, The Commonwealth and International Library, Geophysics Division, Pergamon Press, Oxford, London, Edinburgh, New York, Paris, Frankfurt, 1965, 183 pp., price: 17s 6d.

Notes: The electromagnetic field radiated from a magnetic dipole lying on the ground is considered, in the extremely low frequency range (DC to 20 000 Hertz).Theoretical and experimental data are given on the characteristics of the surface wave (vanishing wave) generated at the air-ground interface, in the case of an homogeneous subsurface.The case of a subsurface with electrical resistivity varying with depth is considered.It is shown how the above-mentioned characteristics may be applied in the quantitative investigation of the electrical resistivity of the subsurface as a function of depth, in a method using the measurements on the ground of all the components of the radiated field: horizontal electrical components, vertical and horizontal magnetic components.

Notes: Book review in this articleHandbuch der Physik/Encyclopedia of Physics, Ed.: S. FlüggeThe Aurora. By S.-I. Akasofu, S. Chapman and A. B. Meinel.Time-Variations of Cosmic Rays. By S. E. Forbush.Magnetic Properties of Rocks and Minerals. By T. Nagata.

Notes: A formula is developed for the vertical magnetic field due to an alternating current passing through a long horizontal cable placed on a two-layer ground. The variations of the phase and amplitude ratio of the vertical field, along profiles perpendicular to the cable line are investigated. Within the limits encountered in practice, it is found that if the upper layer is conductive, as compared to the lower layer, the phase may vary appreciably whereas the amplitude ratio changes as in the case of vacuum.

Notes: Book review in this articleN. A. Ogil'vi, D. I. Fedorovich, Groundwater Seepage Rates. English translation by N. H. Choksy, Consultants Bureau, New York 1966, 33 pp., 12 fig.

Notes: Mapping of fault patterns is an important part of geophysical exploration. A computerized digital template analysis method is described which tests gravity maps for the effects of faults by comparing measured gravity data with calculated master curves. The interpreted gravity data are incorporated in a tectonic map using geological symbols and units, for ready use by the geologists.Tectonics can be investigated by gravity detailing if the smallest undulations on the Bouguer map are taken into consideration. Up to now, residual and derivative gravity maps have explained gravity effects by assuming spherical bodies which are almost unknown in geology. The method discussed here uses tectonic elements, such as fault-blocks and dikes as a basis of interpretation instead of the spherical bodies of the conventional interpretation methods.Gravity data can be easily and relatively cheaply obtained in the early phases of exploration by area wide spot coverage following lines of easy access such as roads, etc. Seismic studies, by contrast, have the disadvantage of being executed along predetermined profile lines. Only after sufficient detailing do seismic profiles permit-if at all -an areal mapping of faults. Thus a tectonic map is obtained only at the end of a geophysical survey instead of being available prior to the planning of costly seismic profiles. The use of gravimetric data and their interpretation by the suggested method provides tectonic detail maps in the early phases of geophysical studies.In addition, this article discusses a general geophysical interpretation method, using the investigation of faults by gravity as an example. Applications of this method for different gravity and magnetics problems as well as for combined interpretations are outlined. Detailed case histories will be published in later articles.

Notes: To be able to make use of all existing probe interpretation techniques, it is desirable that field resistivity observations be conducted in such a way that it is possible to construct an equivalent curve for the surface variation of potential about a point source. Further, the usual parallel layer interpretation will only be justified in as much as the observed potential curve is compatible with such a subsurface geometry. Thus, whilst a potential curve may be constructed from suitable finite potential differences obtained using a Wenner configuration of electrodes, it can be shown, using the tri-potential technique of measurements, that these potential differences may arise partly from lateral resistivity variations.In this paper, a ladder network technique is employed to display these lateral effects and an adjustment method proposed to reduce them. The adjusted potential differences obtained form a consecutive series suitable for summation to give the potential function. These values are subject to further minimum adjustments required for them to comply with slope and curvature conditions for a layered medium. After forming the potential curve by summation, a final numerical smoothing process is carried out. From this smoothed potential curve, corresponding Wenner and Schlumberger curves can readily be derived for interpretation.The method proposed thus attempts to extract from the observed data the maximum part which can be reconciled with a purely depth variation of resistivity. A method is also proposed for compounding the ‘errors of closure’ of the network to provide a Lateral Inhomogeneity Index which gives a measure of the departure of the observed data from the basic interpretation requirements.The method involves no great labour, but can readily be programmed for a computer if desired. Examples are given of the application of the method to field observations. In the interest of objectivity, the final smoothing has been confined to a single stage but in certain very extreme examples a further stage may prove desirable.

Notes: In one geophysical survey over a salt dome in the Gulf of Mexico, data taken from a single magnetic and seismic shipborne traverse demonstrated significantly the importance of magnetic measurements. The reduced magnetic and seismic profiles were integrated with gravity measurements from an earlier survey demonstrating the value of obtaining simultaneous geophysical data. The traverse was approximately 25 miles in length, 135 miles southeast of Galveston, Texas. The observed gradient averaged approximately 2 gammas per 1000 feet and crosses the southwest corner of a large shallow salt dome called the Way Dome. The recorded magnetic profile over the salt dome shows a negative magnetic anomaly extending for approximately 12 miles with a maximum amplitude of approximately 20 gammas. This negatively anomaly is due to the negative susceptibility contrast between the salt and cap rock that truncates the surrounding parent sediments. The shape of the negative anomaly correlates well with the continous seismic record and clearly delineates the topographical and structural features of the salt dome. The recorded analog magnetic profile was replotted, with both the regional gradient and time variations removed, which makes the observed anomaly much sharper than is noticeable on the original recorded strip chart record. A theoretical magnetic anomaly was calculated using a computer program for comparison to the observed anomaly. The results showed good correlation.

Notes: Amplitudes of the vertical ground motion are larger in the critical angle region than in the near vertical region, especially amplitudes coming from deeper boundaries or interfaces with small velocity contrast. Four basic boundary models are used to derive specific travel time patterns for first order and higher order interfaces. The transition from reflected waves to diving waves in the supercritical angle region is shown for the different models.Examples from wide angle surveys in Bavaria and in the Buchara region in the USSR have many characteristic similarities. Travel time patterns and asymptotic velocities are almost identical. The most important boundaries of the continental crust - the Mohorovč Ić discontinuity and the top of the crystalline basement - correspond to two boundary models mentioned before. Amplitude and frequency investigations have been used to derive items of the M-discontinuity. It is certainly a gradient zone and seems to have a lenticular structure with material of stepwise different velocities.

Notes: When a small, transparent replica of a seismic section is illuminated by a homogeneous beam of coherent, monochromatic parallel light a diffraction pattern is created that is representation of the double Fourier spectrum of the recorded seismic waves, i.e. their spectrum in terms of frequency, f, and apparent wave number, k.Masking selected parts of this diffraction pattern causes the spectrum to be filtered: the recomposition of the filtered spectrum then provides a filtered section.The ideal seismic section for this purpose would be a continuous variable density section obtained from recording made at every point of the seismic line. The light transmission coefficient (in terms of light amplitude) at each spot of the replica should be linearly related to the instantaneous seismic signal strength at the spot on the seismic section to which it refers.Unfortunately we cannot make recordings at every point of a seismic line and in our practically realisable recordings we have to be content with sampling in the direction of the location coordinate x. This means that with variable density recordings aliasing will be present and evident in the spectrum obtained in the direction of k; furthermore, the aliased spectrum is also multiplied by a sine function of k because the recording obtained at a given station is not presented on the seismic section as a single line along the time axis, but occupies the entire width of the trace.The diffraction patterns created by variable density recordings of dipping sine waves, including clipped recordings, and of the effect of dip filtering in such sections are discussed. The efficiency of dip rejection is shown to decrease with increasing dip.The diffraction pattern of a variable density recording is found to be characterised by a relationship between point pairs in the pattern.No such simple relationship has been found for the diffraction pattern of a variable area section; the spectra of such VAR sections belong to a very special class, because the amplitude transmission coefficient has only two values, viz. 0 and 1.Consequently, selective masking of the diffraction pattern of a VAR section may give rise to a filtered profile that does not look like a VAR section at all.General statements about the diffraction pattern of VAR sections are hard to give, because the transmission coefficient at a given point in the replica is not proportional to the signal level in the seismic section at the relevant point.In the case of VAR presentation of harmonic waves it was found that, as well as the aliasing effect in the k direction, higher harmonics of the frequency are also introduced.Some synthetic examples are given that show dip filtering to be less effective with VAR than with variable density recordings.Some arguments are advanced in favour of the opinion that high-pass filtering of VAR sections will have less success than low-pass filtering. This is demonstrated by two synthetic examples.

Notes: The theory is explained and practical applications are shown for a numerical procedure in seismology. Particularly the problems concerning the generation of waves under the action of external pressures, and their propagation, in non-homogeneous, both elastic and absorbing media, have been carried out. These problems have been assumed mono-dimensional and refer to plane and spherical waves.The procedure is based on the solution, by means of series, of the wave differential equation, non-homogeneous, and with non-constant coefficients. It is a direct numerical method whose advantage is, mainly, the possibility of tackling, without great difficulties, problems regarding non-homogeneous elastic and absorbing media.On the contrary the methods which require the theoretical expression of the solutions by means of formulae, generally, present conceptual and numerical difficulties.As examples of application of this procedure, the following cases have been carried out by means of numerical calculations.a) Propagation of a wave, initially of symmetrical shape, in a viscoelastic medium; from the results it appears that the wave propagates without losing its symmetry, i.e. without sensible dispersion. A theoretical analysis has been carried out to justify this result, showing that the dispersion in viscoelastic media is noticeable only for relatively high frequencies. It seems that the practical absence of dispersion in field experiments do not exclude necessarily the viscoelastic character of absorption.b) Generation of plane waves under the effect of a uniform pressure distributed on the plane surface of a medium. The way the length and the shape of the generated wave depends not only on the type of pressure acting on the surface but also on the near surface impedance variations has been studied.c) Generation of a spherical wave under the action of a pressure in a spherical hole.The examples treated show how the length and shape of the wave depends on the radius of the hole. Particularly the frequencies of the wave spectrum are proportional to this radius, for a given type of pressure acting in the hole.The characteristics of this procedure would also permit the study of media for which the stress-strain relations are not univocal and linear (non linear absorption). This study, interesting for the wave propagation in rocks, is worth while to be carried out in a special paper.

Notes: For the computation of the vertical component Hz of the magnetic field of a horizontal A.C. dipole lying on the earth's surface, a recurrence formula is presented for a horizontally stratified half space, to obtain the (n+ 1)-layer case from the w-layer case.By means of several computed diagrams for the two-layer case, Hz can be determined for different ratios of conductivity of the subsoil and that of the overburden. Thereby the distance from the dipole as well as the layer thickness h are expressed in terms of the wave length A of a plain wave in the overburden. Assuming a sufficiently large conductivity difference, the results show that evidence about the subsurface conditions can be obtained if the distance between the measuring coil and the dipole is of the order of A/3, and if the thickness h of the layer varies within the range A/100 〈 h 〈 A/6.As an example for the 3-layer case, a nonconducting intermediate layer is assumed.

Notes: A nomogram is presented which enables evaluation of the components of magnetic attraction of a homogeneous finite rectangular prism, and of gravitational attraction due to a uniform rectangular lamina.In practice any three-dimensional body could be approximated by a number of right rectangular prisms of varying dimensions governed by the shape of the body. The magnetic attraction of the whole body is then obtained by numerical summation of the effects of the constituent prisms.For evaluating the gravitational effect, the cross-section of the body corresponding to each elevation contour is approximated by a number of rectangular laminae (or by a stepping polygon) the attraction of which can be determined with the aid of the same nomogram. The total gravitational attraction of the body is obtained by a process of graphical integration along the vertical axis.

Notes: In [50] and [51] a theory has been developed relating formation factor, permeability and porosity of porous sedimentary rock by means of statistical parameters of the pore system, and further, tying those statistical parameters to other macroscopically measurable quantities like capillarity, capillary retention, flow dispersion etc. This paper deals with experimental methods and apparatus for checking the theoretically derived relations using columns of packed loose or artificially consolidated sands or other granular matter. Some initial experiments, mainly intended for checking out equipment and methods are reported. The discussion of the results so far shows good agreement with the theory in most cases, except for the irreducible water saturation. However, for a definite statement on the general validity of the theory more data must be accumulated.

Notes: Some of the methods such as regional removal and second derivative calculations which can be used to outline anomalies on potential data maps can be thought of as a filtering operation. The analysis and design of such two-dimensional filters by means of direct and inverse two-dimensional Fourier transforms have been considered.An analysis of several published sets of second derivative coefficient sets indicates that, in general, they are not a good approximation to the theoretical second derivative filter. Alternate methods of designing regional removal and second derivative filters are discussed. The properties of various two-dimensional filters are further illustrated by means of maps obtained from the convolution of several of these filters with a set of observed field data. These maps show the large changes in anomaly shape which can result from the inclusion or rejection of various wavelength components.

Notes: Integration of the continuous seismic reflection profiler with the marine refraction method on engineering surveys offers a solution to hidden layer problems, allowing both layer velocity and thickness to be computed.

Notes: This paper is the follow-up of an earlier paper by the same author on the calculation of standard-graphs for horizontally stratified subsoils. The method which was developed in that earlier paper was destined for handwork; it was laid down in master-tables. The present paper deals with the presentation of similar methods to the computer expert in purely mathematical denotation. Two different denotations are described for the calculation of the image pole strengths involved. The first denotation is an improved version of Watsons formulae; it gives the total strengths. The second denotation preserves the character of successive approximations as described in the previous paper. Both denotations have been worked out until a six layer resistivity profile, but actually there is no limitation to the number of layers. There is no restriction to the resistivities of any layer. The only condition is now that all interface depths must be integers.This paper is followed by a paper on the relevant computer program by Argelo in this same issue

Notes: Book review in this articleJ. Frihagen, Electron Density Profiles in Ionosphere and Exosphere, North-Holland Publishing Company, Amsterdam, 1966, price N. fls. 60,–.J. A. E. Allum, Photogeology and Regional Mapping, Pergamon Press, London, 1966, 107 pages, 16 plates, 23 figures, price 17 s 6 d net.

Notes: High precision gravity surveys have to be examined at different points of view: the accuracy which one can expect on the final results, regardless to their distribution, the shape and amplitude of the expected anomalies, depending on these factors, which grid of stations is convenient in each particular case.Under certain condition, using an appropriate procedure, involving strict criteria, it is possible to get on the Bouguer map the same accuracy as the reading one.However an accuracy closed to 0,01 mgal does not imply that anomalies as 0,01 or 0,02 mgal deserved attention. Numerous factors limit our appreciation of significant anomalies to 0,05 mgal, may be a little less.When cavites are concerned, it is always necessary to define the extreme dimensions an depth of volumes which may give detectable anomalies.Some example are given illustrating different aspects of this particular type of geophysical prospecting.

Notes: Several papers presented at the last SEG Convention in Houston by Schneider, Backus et al have shown how important and fruitful it was to obtain a continuous knowledge of the velocity functions and they have solved their problem by a Dynamic Correlation Analysis. Our purpose is to introduce here a method based on the best summation of a set of traces instead of the best correlation.Practically, this approach has several advantages:1) Two traces only can be correlated at each step whereas the summation can bear on any number of them;2) Optimizing the summation is actually what we are looking for since, at the long end, the success of the improvement is evaluated from the compositing of several traces either weighted or not.On the other hand, an advantage of correlation is the possibility of adding correlations obtained at several places in a same neighbourhood in order to improve the results. With the summation method this is feasible only when dips are inexistent: we shall see that the difficulty due to the dip effect can be turned around.The basic principle of the method can be summed up as follows: traces relating to a same reflection point are considered; several composites are made, each after applying different move out corrections ranging widely around an estimated adequate velocity function. At each time coordinate, the best adapted velocity function, i.e. the one that yields the best phase relation between reflected events, corresponds to the composite trace the average amplitude of which is the largest.This way, the velocity function corresponding to primary reflections as well as those corresponding to multiple reflections can be established accurately.Some examples are shown.

Notes: The problem of elastic waves–from point sources–in layered media is solved in a general and elementary way. Only the simplest principles of the Theory of Functions are necessary. The solutions can immediately be used for numerical applications.

Notes: The symmetry shown, by the function describing the magnetic anomaly due to a dyke or vertical fault step leads to a method by which an observed profile may be adjusted to conform with that symmetry. By making these adjustments a minimum the ideal dyke or fault profile closest to the observations is constructed. In three of four possible situations this is interpreted by simple geometry.Parallelpiped models may be transformed into two dykes for symmetry analysis. Depth limited models are not so amenable, even in special cases.

Notes: The use of digital recorders and computers in seismic exploration promises major enhancement of the quality of final documents available to interpreters. The ultimate objectives of recording and processing remain what they always have been:1 Record the reflection wavelet as a function of time; this requirement has been met with satisfactory accuracy for a number of years.2. Record the reflection wavelets with sufficient fidelity to permit the interpreter to recognize them.Various factors affect our ability to achieve this second objective. Certain recording errors are associated with digital recording systems. However, an understanding of the sources of error will enable the operator to use his system properly and to estimate the noise level or inaccuracy of field recordings. Field operations do not require rigorous error analysis; in most cases a satisfactory approximation can be obtained from simple calculations.Three types of “noise”–seismic, instrument and power line–introduce errors. Factors which contribute to over-al recording system error include specifically input noise, power supply ripple, crosstalk, A-D conversion error, quantizing noise, aliasing, distortion. Examination of each component of a recording system, permits the determination of its ultimate effect on the over-all noise level–or error level–of the entire system.Many of the error sources produce statistically independent noise which is not correlative. Where this is true, error voltages from various sources may be combined by taking the square root of the sum of the mean square noise voltages, giving a result slightly greater than the largest single voltage if one source is much greater than any other source. This simplification can be used to estimate over-all system noise levels. Distortion and crosstalk depend on signal amplitude and should be added algebraically in each category. Each final sum should be used as a statistically independent noise source with respect to other system noise sources.Using the foregoing examples and simplified system for estimating over-all system noise, and assuming that much of the distortion (which limits signal/instrument noise ratio to 54 db) can be removed by filtering, we determine that the combined effect of all sources of error is to reduce the system S/N ratio to approximately 74 db.With proper care digital field recording systems can produce very good field records, and exotic computer processes can enhance signal and reduce various forms of noise. However, one always must recall that the level of confidence which one can place in an interpretation of seismic data must be dependent on a knowledge of the accuracy of the basic data.

Notes: The Terrapak is a new seismic energy source of the surface energy source type. Essentially, the Terrapak consists of a compressed air piston which transmits a shock to the ground by means of a striker plate attached to the piston rod. The Terrapak is truck-mounted together with its ancillary equipment. Shocks can be generated at 8 second intervals, and although the weight of the striker is relatively low (approximately 1400 Ibs) the impact velocity exceeds 66 ft/sec. The energy available is about 85,000 ft. lb., which is equivalent to that produced by conventional weight-dropping methods. The power spectrum of the seismic wave produced by the Terrapak is spread out towards the higher frequencies because its impact velocity is greater than that of a dropping weight.There is a noticeable difference between noise records made with the Terrapak and noise records made with a conventional weight-dropping technique. The same noise frequencies are found in both cases, but low frequency noise is stronger with weight dropping than with the Terrapak, whereas the intermediate frequency reflections obtained using the Terrapak are more suitable for correlation.The expansion of the compressed air generates a sound wave, the effects of which must be eliminated by the use of multiple geophone arrays. A spectrum analysis of the records has confirmed that the waves produced by the Terrapak are rich in intermediate frequency components. This facilitates the picking of reflections in normal areas where the apparent frequency of the reflections is about 30 to 35 c/s.

Notes: This paper includes publication of two algorithms, to be processed on a digital computer. The algorithms are based upon the two mathematical denotations, presented by Dr. J. C. van Dam in this same issue. The computer programs are written in Algol, in the form of procedures (i.e. subroutines to be activated from a surrounding Algol program).Each of the two procedures is preceded by a numerical analysis. Some remarks are made about the reliability of each of the two procedures, the production and the computing time required.

Notes: The theory of statistical communication provides an invaluable framework within which it is possible to formulate design criteria and actually obtain solutions for digital filters. These are then applicable in a wide range of geophysical problems. The basic model for the filtering process considered here consists of an input signal, a desired output signal, and an actual output signal. If one minimizes the energy or power existing in the difference between desired and actual filter outputs, it becomes possible to solve for the so-called optimum, or least squares filter, commonly known as the “Wiener” filter. In this paper we derive from basic principles the theory leading to such filters. The analysis is carried out in the time domain in discrete form. We propose a model of a seismic trace in terms of a statistical communication system. This model trace is the sum of a signal time series plus a noise time series. If we assume that estimates of the signal shape and of the noise autocorrelation are available, we may calculate Wiener filters which will attenuate the noise and sharpen the signal. The net result of these operations can then in general be expected to increase seismic resolution. We show a few numerical examples to illustrate the model's applicability to situations one might find in practice.

Notes: In order to adequately understand the complicated, anelastic processes governing wave propagation in soils or highly weathered rock it seems desirable first to have available a convenient laboratory material for such propagation studies the frequency dependent rheological parameters of which are known beforehand. A property measurement program has been conducted to determine the complex Young's modulus and the complex shear modulus of a commercially available viscoelastic material over a broad spectral region.

Notes: In the year 1958 the Service for Water Management of the „Rijkswaterstaat” started its program of geo-electrical resistivity prospecting in the western part of the Netherlands. The aim of this program was to obtain data on the salinity distribution of the ground water.The ground water regime in this part of the Netherlands is most intricate. This is due to the geological and geo-hydrological conditions and to the low elevation of the land. Many reclaimed areas are up to several metres below mean sea level.The resistivity data obtained are closely related to the salinity of the ground water. On the basis of bore hole data it was even possible to arrive at calibration curves for the salinity of the ground water in sand deposits. Under special conditions it was also possible to draw conclusions with respect to the presence of less permeable formations as e.g. clay layers.Some remarks are given on the practical performance and the interpretation of the measurements.A review is given of the work done until now. Some results are shown by means of maps of the salinity distribution of the ground water in the western and northern parts of the Netherlands.Two examples are described of the use of the data obtained during the survey in the province of Zuid-Holland.Another two examples are presented of detailed investigations for special purposes in relatively small areas.

Notes: In mountainous areas it is an inadequate procedure to reduce gravity observations by merely subtracting the effect of an infinite flat slab of material between the station and sea-level, and adding a terrain correction. A programme is described which directly computes the effect of masses above sea-level, and mass-deficiencies below it; as well as the effect of compensating masses under the Pratt and Airy isostatic systems. As an example, the method has been applied to a regional gravity survey of Papua and New Guinea where it is seen to remove the usually high correlation of the Bouguer anomaly with local topography.

Notes: The present paper shows that the techniques developed and exploited by qualified geophysicists have brought high sensitivity magnetic surveys to an industrial stage.It will appear that for most mining and oil problems, either on land or sea, the necessary modern equipment already exists without developing it further in the future. In particular, the digitalization of data is practically finished for the magnetometer itself as well as for some navigation techniques.

Notes: Simultaneous measurements made on an ice island and about 1000 ft. below show that magnetic anomalies can be detected in the presence of large time variations of the magnetic field. Attenuation and phase lag of time variations at depth are measurable but do not limit the utilization of the vertical gradient of geomagnetic total intensity for defining crustal anomalies.

Notes: As shown previously [50], the relations between formation factor, permeability, and porosity can be expressed in statistical parameters of the microscopic pore system. A number of other macroscopically measurable quantities depend on those same parameters. Thus, by proper combination of these quantities, it should be possible to solve for those parameters, that cannot be retrieved by direct methods. In this article, the dependencies on these statistical parameters of the capillarity with imbibition and drainage, the irreducible water saturation, the flow dispersion with miscible displacement, and quantities that are directly observable at ground surfaces or thin sections, are preliminarily studied as a preparation for possible practical measurements.

Notes: A system of geophysical units is proposed which is based on the International System of Units, using the meter, the kilogram, the second and the ampere as fundamental units. A historical introduction is given and the reasons for preferring the use of the International System of Units in exploration geophysics, are explained.At the meeting of the European Association of Exploration Geophysicists at Stockholm a resolution will be proposed recommending the use in exploration geophysics of the International System of Units.

Notes: A two dimensional linear filter operator based on Strakhov's method for the extraction of a potential field signal (gravity or magnetic) from a background of homogeneous random noise has been developed. An algorithm to solve for the coefficients of the operator is given together with the corresponding computer program in FORTRAN language. It may be used on any machine using FORTRAN IV. A few examples of the operator are also included.

Notes: The design of least-squares optimum filters is based upon minimizing a suitably defined error criterion. The expected value of this error is easily computable after the coefficients of the filter have been determined.When a particular filtering problem is specified, there are several parameters which are specifically not included in the optimization procedure. However, the magnitude of the expected error may be quite sensitive to these parameters. The examination of the relative values of the expected error for variations of these unspecified parameters may lead to a better definition of the filter problem.The parameters which are left unspecified by the general least-square filter definition include:1. The addition of white noise to the signal autocorrelation to stabilize the filter behavior.2. The specification of the shape of the desired output of the filter.3. The specification of the lag between the desired output and the input.Examples are given showing the relationship between these parameters and the value of the expected error.

Notes: Zusammenfassung An Hand einer 16tägigen Frühjahrblockingsituation (2. 3. bis 18. 3. 1955) wurden die dynamischen Vorgänge bei der Bildung und Aufrechterhaltung der Blockinglage studiert. Während in der Vorperiode des Blockings ein Nordwärtstransport von absolutem Rotationsmoment der Geschwindigkeit der Luft stattfindet, wird während der Blockingsituation selbst das absolute Rotationsmoment nach Süden verfrachtet. Weiters wurden die Entwicklungsvorgänge von 25 Blockingfällen während eines Zeitraumes von acht Jahren genau analysiert und die wichtigsten Ergebnisse tabellarisch zusammengestellt.

Notes: Zusammenfassung Aus 21 571 täglichen Höhenwindmessungen werden für jeden Monat die Änderungen der skalaren und der vektoriellen Mittelwerte der Windgeschwindigkeit, der zonalen und der meridionalen Komponenten der Windgeschwindigkeit, der resultierenden Luftversetzung und der Beständigkeit des Windes mit der Höhe bis 30 km über Wien sowie der Jahresgang der Windgeschwindigkeit und der Häufigkeitsverteilung der Windrichtungen für die verschiedenen Höhenstufen abgeleitet und in ihren Besonderheiten eingehend diskutiert und zu erklären versucht. Dabei ergibt sich, daß in den Übergangsjahreszeiten die Höhenwindverhältnisse in einzelnen Monaten ein auffallendes Verhalten zeigen, das nicht einfach zu erklären ist. Die Jahresgänge der skalaren wie auch der vektoriellen Geschwindigkeitswerte weisen auch, abgesehen von den bodennahen Schichten, bereits in der Troposphäre Doppelwellen auf, deren Extreme in der oberen Troposphäre zum Teil den Extremen in der unteren Stratosphäre entgegengesetzt sind. In Höhen über 18 km erfolgt der Übergang von der im Winter vorherrschenden westlichen Strömung zum sommerlichen Ostwind im Frühling allmählich von den höchsten Schichten nach unten fortschreitend, der umgekehrte Übergang vom August zum September dagegen sehr scharf. Es ist daher notwendig, bei Untersuchungen der Höhenwindverhältnisse die einzelnen Monate besonders in Betracht zu ziehen, da bei einer Zusammenfassung nach Jahreszeiten wesentliche Merkmale verwischt werden.

Notes: Summary The heat balance equation for the bottom surface of floating sea ice is evaluated on the basis of observations of ice temperature, water temperature, current velocity, and ablation or accretion of ice. Assuming equality of the eddy diffusivities for momentum, heat, and salt (average 24 cm2 sec−1) it is shown that the temperature gradient in the oceanic boundary layer is extremely small (averages between 2.10−5 and 4.10−4°C/meter) and difficult to measure directly. It is suggested that a large part of the heat transfer from the relatively warm Atlantic water to the arctic atmosphere may occur through open leads in the ice cover.

Notes: Zusammenfassung Der zeitliche Verlauf der Vormittags-Anomalie in den Tagesgängen der kritischen Frequenzen der normalenE-Schicht (Verlangsamung des Anstieges der Elektronendichte kurz vor dem Ortsmittag im Vergleich zur Chapman-Schicht) wurde unter vereinfachten Voraussetzungen für 80 ausgewählte Tagesgänge des Jahres 1958 berechnet. Die erhaltenen Ergebnisse werden mit der Appletonschen Theorie verglichen.

Notes: Zusammenfassung Aus der 300mb-Fläche der täglichen Wetterkarte des deutschen Wetterdienstes wurden für den Zeitraum von 1955 bis 1963 Lage, Richtung und Geschwindigkeit der hochtroposphärischen Strahlströme bestimmt. Die jahreszeitlichen Änderungen der Positionen, Intensitäten und Richtungen des Polarfront-Jet (PFJ) und des Subtropen-Jet (STJ) werden für den Bereich von 20° W bis 20° E und von 35° N bis 70° N angegeben und diskutiert.

Notes: Zusammenfassung Die Variationen des Gesamtozonbetrages an zehn europäischen Stationen wurden paarweise korreliert. Die Korrelationskoeffizienten fallen im Mittel exponentiell mit der Entfernung der Stationen ab. Aus diesem Abfall wurde die mittlere Ausdehnung stratosphärischer Luftpakete mit 670 km abgeschätzt. Eine zeitliche Verschiebung bei der Berechnung der Korrelationskoeffizienten veranschaulicht den vorwiegend zonalen West-Ost-Ozontransport.

Notes: Résumé Une particule qui ne subit que des transformations adiabatiques, occupe sa position d'équilibre au sein d'une masse d'air en équilibre hydrostatique, lorsque la sommeS de son enthalpie spécifique et de son énergie potentielle par unité de masse est extremum. Suivant que cet extremum est un minimum ou un maximum, l'état d'équilibre hydrostatique est stable ou instable. On peut généraliser cette proposition au cas de l'état de mouvement géostrophique, à condition d'ajouter, à la sommeS, l'énergie cinétique longitudinale, par unité de masse, de la particule. On peut étendre immédiatement ce dernier résultat au cas du tourbillon circulaire permanent.

Notes: Zusammenfassung Viele Kaltfronten, die mit Südkurs den Alpenhauptkamm überschreiten und in das Südalpengebiet eindringen, sind dort außerordentlich wetterwirksam. Andere Kaltfronten, die über die Alpen hinwegziehen, werden dagegen in den Südalpen durch Föhnerscheinungen fast völlig aufgelöst. In vorliegender Arbeit wird an Einzelbeispielen das Verhalten von Kaltluftströmungen beim Überqueren der Alpen und beim Eindringen in das Südalpengebiet eingehend untersucht. Dabei zeigt sich, daß durch charakteristische Merkmale der Strömmungen eine einwandfreie Unterscheidung der beiden Arten von Kaltlufteinbrüchen in das Südalpengebiet möglich ist. Vor allem lassen sich beide Fälle durch Anwendung der Höhenwetterkarte gut auseinanderhalten. Es ergibt sich, daß eine Kaltfront dann die Südalpen wetterwirksam überquert, wenn dieses Gebiet auf der Vorderseite eines in der Höhenkarte in Erscheinung tretenden Höhentroges liegt, daß dagegen die Front durch Föhnwirkung aufgelöst wird, wenn die Südalpen auf der Rückseite des Höhentroges liegen.

Notes: Zusammenfassung Im folgenden wird ein Überblick über die Untersuchungen über die allgemeine Zirkulation der Atmosphäre in den mittleren Breiten der Erde gegeben, die vom Department of Meteorology of the University of Chicago unter der Leitung von Prof.C. G. Rossby im Akademiejahr 1946 bis 1947 ausgeführt worden sind. In der zonalen Zirkulation der mittleren Breiten der Nordhemisphäre zeigt sich vor allem im Winterhalbjahr normalerweise zwischen 5 und 15 km Höhe ein verhältnismäßig schmales Band von sehr starken Westwinden, das den Charakter eines Freistrahls besitzt. Das Intensitätsmaximum dieses Windbandes tritt im Tropopausenniveau (300 bis 200 mb) auf. Südwärts des Windmaximums nimmt die Windgeschwindigkeit sehr rasch auf niedrige Werte ab. Das zonale Windband liegt innerhalb oder knapp südlich einer ebenfalls relativ schmalen Zone, in der der Temperaturgegensatz zwischen den polaren und äquatorialen Gebieten konzentriert ist. Im Bereich des zonalen Windbandes steigt die Tropopause steil an, wobei häufig sogar eine Unstetigkeit auftritt, indem nördlich desselben ihre Höhe jener der polaren Atmosphäre entspricht, südlich davon jener der äquatorialen. Unter dem Windband liegt häufig eine gut ausgebildete Frontalzone, die in den oberen Troposphärenschichten etwas nördlich des Windbandes endigt. Das obere Westwindband zeigt rund um die ganze Erde einen wellenförmigen Verlauf mit Wellenlängen von etwa 50° bis 120° Längengraden. Diese Wellen weisen nur eine geringe Fortpflanzungsgeschwindigkeit auf und scheinen mit den gewöhnlichen kurzen, instabilen troposphärischen Frontalwellen keine nähere Beziehung zu haben. Anderseits scheinen sie sowohl das Verhalten, wie auch die Bewegung dieser kurzen unteren Wellen in maßgebender Weise zu beeinflussen. Die oberen Wellen sind insofern instabil, als die meridionale Schwingungsweite (Mäanderung) allmählich sich so verstärkt, daß es an den Rändern des Windbandes zur Bildung von Wirbeln kommt: auf der Südseite zyklonischer Natur und kalten thermischen Aufbaues, auf der Nordseite antizyklonischer Natur und warmen thermischen Aufbaues. Diese Ausstoßung von Luftmassen aus dem Windbandbereich führt zu einem Luftmassenaustausch zwischen hohen und niedrigen Breiten, der wie es scheint in den troposphärischen Schichten oberhalb 700 mb von ausschlaggebender Bedeutung ist. Theoretische Untersuchungen zeigen, daß die beobachteten meridionalen Windprofile im Tropopausenniveau recht gut mit solchen übereinstimmen, die der Forderung einer konstanten vertikalen Wirbelkomponente im Bereich des großräumigen seitlichen Austausches der mittleren Breiten genügen. Solche theoretische Windprofile zeigen in niedrigen Breiten ein so großes meridionales Windgefälle, daß es am Südrand des Windbandes zu Trägheitsinstabilitäten kommt. Sie führen zu einem mehr oder minder unvermittelten Abbruch der meridionalen Windzunahme in 40° bis 30° Br. Das gleichzeitige Auftreten von Windband und Frontalzone darunter führt zur Schlußfolgerung, daß es bei der Ausbildung des Westwindbandes zu einer dynamischen Konzentration von Solenoiden in seinem Bereich kommen muß, zu ähnlichen Vorgängen, wie sie bei ozeanischen Strömen auftreten. Im Anschluß an diese hier kurz angedeuteten wichtigen Ergebnisse dieser neueren amerikanischen Arbeiten wird auf einige Ergebnisse österreichischer Untersuchungen hingewiesen, die einige Fragen der obigen Probleme betreffen.

Notes: Summary Measurements of the isothermal-isobaric volume retardation in crosslinked and non-crosslinked polystyrene are reported. The measurements have been carried out applying the temperature-jump method, and, for the first time, also the pressure-jump method. For the measurements using the temperature-jump method a quartz-glassdilatometer has been used which allows the registration of volume changes of ±7·106 cm3. A pressure dilatometer has been developed for the measurements according to the pressure-jump method which permits volumemeasurments of the same precision in the pressure-range between 1 and 60 atmospheres. The experimental results show that for the volume retardation of polystyrene a measurable linear region exists. For this case of linear retardation behaviour various kinetic theories predict an exponential time dependence of the deviation of the volume from the equilibrium value, which is due to the existence of a single retardation time. This result is not confirmed by our experiments. The volume retardation in the linear region — at least for polystyrene — can in no case be described in terms of a single retardation time, but only by a distribution of retardation times. It turns out, that the retardation function (distribution function of retardation times) in the linear region differs after a previous temperature change from that after a previous pressure change. This result can be confirmed by theoretical considerations which follow fromMeixner's thermodynamic theory of linear relaxation phenomena.

Notes: Résumé Le comportement en viscosité sous différentes vitesses de cisaillement, à différentes températures, de solutions d'alginate de sodium à des concentrations variant entre 0,05% et 1%, auxquelles on a ajouté du chlorure de calcium en quantité variable, est qualitativement toujours le même; pour des quantités croissantes de chlorure de calcium, à concentration fixe en alginate de sodium, à une phase de dépression de la viscosité succède une phase de croissance très rapide, suivie à nouveau d'une phase de décroissance. Dans la première phase les variations de la viscositè avec la vitesse de cisaillement sont représentables par un modèle répondant à la Théorie d'Eyring; dans les phases suivantes l'écoulement est représenté par une loi du type η=aγb avec b〈0. Cette différence dans le mode d'écoulement tiendrait à l'apparition, à partir d'une concentration en chlorure de calcium suffisante, d'une structure tridimensionelle plus ou moins stable suivant la concentration en ions calcium.

Notes: Zusammenfassung Eine Versuchsanordnung wird beschrieben, in derSearle- undCouette-Typ des Rotationszylinderviskosimeters durch leichten Umbau zu erhalten sind. Für alle Fälle (Außen- und Innenzylinder desSearle- undCouette-Viskosimeters) werden die Drehmomente in Abhängigkeit von der exzentrischen Stellung der Zylinderachsen für mehrere Drehzahlen und Zylinderlängen bestimmt. Alle von der Theorie vonW. Müller über die Drehmomente gelieferten Aussagen lassen sich demonstrieren und in verhältnismäßig weiten Bereichen quantitativ belegen. Es werden die Möglichkeiten behandelt, wie die im Einzelfall nur mühsam zu berechnenden Beiwerte leicht zugänglich bereitzustellen sind.

Notes: Zusammenfassung Amorphe Polymere ausreichend hohen Molgewichts befinden sich in einem dynamischen Gleichgewicht der Verhakung ihrer Moleküle. Dabei diffundieren die Moleküle ständig mit ihren Kettenenden durch die Schlaufen der tetraederförmigen Verhakungen, lösen dabei eine Verhakung und bilden sofort wieder eine neue an anderer Stelle, so daß das MolgewichtM c der Kettenstücke zwischen den Verhakungsstellen zeitlich konstant ist. In der Nähe der Kettenenden werden Verhakungen häufiger gelöst und wieder gebildet als mehr in der Mitte der Fadenmoleküle. Dort bleiben deshalb Dehnungszustände der Kette länger erhalten als an den Kettenenden. Mit dieser Vorstellung kann man die mechanische Relaxation der Polymeren gut beschreiben. Man benötigt dazu außer dem Molgewicht drei Konstanten.-Beim Fließen der Polymeren werden die in der Mitte liegenden Kettenstücke wegen ihrer großeren Relaxationszeit stärker gedehnt als die am Kettenende liegenden Teile. Im Gleichgewicht stellt sich eine Dehnungsverteilung ein, mit der man dieNewton-Viskosität berechnen kann. Strukturviskosität tritt dann auf, wenn in der Dehnungsverteilung starke Dehnungen auftreten. Bei starker Dehnung löst sich ein Kettenstück schneller als normal aus seinen Verhakungen, weil es dann auf die Verhakungpunkte eine größere Kraft ausübt als in ungedehntem Zustand.

Notes: Summary A mechanical system consisting of an inert component, attached to a linear viscoelastic spring, is studied theoretically. Basic assumptions about the viscoelastic material areBoltzmann's superposition principle and a positive discrete relaxation spectrum. The equation of motion and its formal solution for free damped vibrations are discussed. The theory focusses on the determination of the complex dynamic modulus, defined for undamped sinusoidal vibrations, by free damped vibrations. Simple approximation formulae to calculate the dynamic modulus from free vibration data, i. e. eigen frequency and logarithmic decrement, are given; upper limits for the approximation errors could be derived.

Notes: Résumé Après un bref rappel des méthodes d'étude des matériaux bitumineux, suivi de la description des appareillages mis au point pour l'étude expérimentale du fluage, sont exposés les résultats des essais de traction et de cisaillement par torsion. Ces expériences, effectuées sur des éprouvette d'un béton bitumineux de type classique, mettent en évidence que: Le domaine de comportement linéaire du matériau est très restreint en ce qui concerne l'intensité de la contrainte appliquée ou la grandeur de la déformation. La réciprocité entre les rôles du temps et de la température dans la description des propriétés mécaniques du matériau est vérifiée. L'application de la méthode des variables réduites permet alors d'étendre les connaissances acquises, en dehors du domaine étudié. Les propriétés rhéologiques du matériau peuvent être présentées sous forme d'expressions analytiques simples. Il est aussi possible d'attribuer au matériau un modèle comprenant sept paramètres dont six d'entre eux sont indépendants de la température, le dernier ne dépendant que de la susceptibilité thermique du matériau La susceptibilité thermique elle-même peut être présentée sous forme analytique simple. L'étendue des recoupements qui peuvent être faits à partir des essais de fluage en traction et en torsion et la concordance des résultats obtenus par les méthodes statiques et dynamiques, mettent en évidence le caractère intrinsèque des informations acquises.

Notes: Summary Transient creep recovery tests in simple tension were performed in a series of cross-linked high polymers in pure and plasticized states. A loading cycle was adopted according to which each specimen was loaded in creep for a time period of 16′ followed by recovery for the same time period. This loading cycle was repeated for various steps of temperature from ambient temperature up to a temperature corresponding to the rubbery region of each polymer. It was shown that, while the 15″ measurements of deformation after loading or unloading were approximately equal, recovery individual curves were always lagging in time the corresponding creep curves. Composite curves of creep or recovery deformation in semi-log time scale reduced to a temperature of 30 °C were plotted by applying the method of reduced variables. The creepdeformation composite curve was always advancing in time relatively to the respective recovery composite curve. This phenomenon was an accumulation of the partial difference of the corresponding individual curves. Time-shift factor versus temperature curves for creep and recovery were plotted and compared. It was established that the remaining deformation after 16 minutes of a 16′ creep recovery normalized to the initial deformation at the beginning of recovery, if plotted versus temperature, presented the same shape of curves for all types of materials tested. The maxima of these curves were diminishing with addition of plasticizer according to a straight line.

Notes: Summary In order to investigate the thermal effects occuring in a coaxial cylinder viscometer, the temperature changes at the onset of the flow and the temperature profiles reached under steady-state conditions have been measured, at different radial positions, by means of an NTC resistor. The results have been found to agree satisfactorily with the equations developed for the theoretical description of the above effects.

Notes: Summary A typical property of greases, as plastic disperse systems, is their thixotropy (reversible destruction of their structure due to deformation). In relation to this, if the rate of their formation drops below a certain critical value it becomes practically very difficult or even impossible to attain steady conditions of their flow. This is observed both in rotational plastoviscometers and in rolling-contact bearings, and is manifested in more or less sharp fluctuations of the resistance moments. The critical value of the rate of deformation depends on the nature of the grease and the rigidity of the braking device or the power reserve of the drive, decreasing when these values are increased. When soap greases are deformed they become anisotropic, which, when the direction of deformation is changed, tells perceptibly on their resistance to deformation and results in fluctuations of the resistance moments in rolling bearings.

Notes: Summary The bahavior of granular materials in theMac Michael type viscometer was studied. The deflection angle of the bob decreased with the increase of the rate of rotation of the cup in the cases of these materials contrary to those of liquids. The powder bed in the gap of the viscometer is divided into twp cylindrical parts, the inner one with flowing layers of particles and the other moving with the cup as a bulk. The existence of these two parts is considered responsible for the extraordinary behavior of powder in the viscometer. The coefficient of kinetic friction of powder layers was obtained by applyingBenarie's analysis to our results.

Notes: Summary Consideration is given to the unsteady motion of a lamina moving under a constant force in an idealised elastico-viscous liquid contained between walls parallel to the lamina. It is shown that the velocity of the lamina is strongly dependent upon the elasticity of the liquid. Both the time at which the velocity of the lamina attains an effective steady value and the corresponding distance travelled by the lamina depend in a marked way upon an elastic parameterλ.

Notes: Abstract An unusual stress controlled turbulent flow phenomenon observed in aqueous solutions of some derivatives of an unsaturated 18 carbon atom fatty acidis described. Some other unusual viscometric and rheogoniometric properties of these solutions are also discussed.

Notes: Summary A description is given of an instrument for the measurements of the dynamic shear modulus,G, and the corresponding damping, tanδ, of solid polymeric materials. The instrument is suitable for the measurement of moduli in the range from 106 to 1010 newton/m2, tanδ values from 0.005 to 3 and frequencies between 0.1 and 20 Hz. The temperature of the specimen can be adjusted to any value between −180 and + 300

Notes: Zusammenfassung Beim Durchfluß von hochpolymeren Schmelzen durch ein elliptisches Rohr wurden Sekundärströmungen nachgewiesen. Das beweist, daß die untersuchten viskoelastischen Substanzen (Polyäthylen, Polystyrol, Polymethylmethacrylat) nicht zur Klasse derWeissenberg-Flüssigkeiten gehören.

Notes: Zusammenfassung 1. Zur Feststellung, unter welchen Bedingungen tierische Haare (Keratin) kautschukelastisch werden, wurde der lineare thermische Ausdehnungskoeffizient (l. th. AK. α) bei Roßhaaren unter Variation der Reagenzien und Temperaturen gemessen. 2. Keratinfasern verhalten sich im trockenen sowie im gequollenen Zustand wie normale Festkörper, indem α positiv ist. Auch nach Reduktion eines Teiles der Cystinquerbindungen bleibt α positiv. 3. Nach Spaltung der Wasserstoffbrücken zwischen den Peptidketten, z. B. durch Einwirkung von Phenolen, erfolgt Superkontraktion der Faser. Hierbei wird α negativ und zwar unter der Voraussetzung, daß die Bedingungen, bei-welchen die Superkontraktion erfolgt, insbesondere Temperatur und Medium, beibehalten werden. Ein Umschlagen des AK. findet auch durch Behandlung von Keratinhaaren mit Natronlauge bei Zimmertemperatur statt. 4. Keratinhaare kommen in folgenden Zustandsformen vor, zwischen denen keine scharfe Grenze besteht: a) Normaler Festkörper mit positivem AK. und hohem E-Modul b) Partiell verflüssigter Festkörper mit negativem AK. und stark herabgesetztem E-Modul.

Notes: Zusammenfassung Die Feststellung, da\ mit vielfachen Quellungen und Entquellungen behandelte Fasern ein Absinken des maximalem Quellvermögens zeigen, legt nahe, auch die mechanischen Eigenschaften von Fasern nach Quellungsbehandlung zu untersuchen. Dies wurde an drei verschiedenen Fasertypen durchgeführt. Bei der im Müller-Bad gesponnenen Zehlendorf-F-Faser und der Eiwei\faser Tiolan sinkt bei etwa konstant bleibender Rei\festigkeit die maximale Dehnung merklich. Bei der im Trichterspinnverfahren gewonnenen Schwarza-W 1 sinkt sie ebenfalls oder bleibt konstant je nach der Art der Mittelung. Doch steigt in letzterem Beispiel auf jeden Fall die Rei\festigkeit eindeutig an. Die relativen Knoten- und Schlingenfestigkeiten reagieren ebenfalls auf Quellungsbehandlungen mit einem mehr oder weniger starken Absinken. Noch stÄrker zeigt sich der Einflu\ auf die Knickbruchfestigkeit, wenn man von Baumwolle absieht. Dieses Verhalten lÄ\t sich im allgemeinen dadurch verstehen, da\ eine vielfache Quellung und Entquellung die Packungsdichte der Fasern verÄndert und die einzelnen Molekülteile in energetisch tiefere Lagen zueinander einspringen lÄ\t.

Notes: Zusammenfassung Die Verkürzung verschiedener Keratinfasern in 50proz. Phenol wurde in Abhängigkeit von der Temperatur untersucht. Die zur Erzielung einer mittleren Schrumpfung der Haare erforderliche Temperatur (Erweichungstemperatur) hängt von der Herkunft der Haare ab. Schafwolle erweicht bei 84°, Menschenhaar bei 95° C. Zusammenhänge zwischen der Erweichungstemperatur, dem Verhornungsgrad, Cystingehalt und dem histologischen Aufbau der Fasern werden besprochen.

Notes: Zusammenfassung Es wird ein Verfahren zur quantitativen Bestimmung von freien Alkalimetall-Kolloiden in Organosolen angegeben. Dabei wird das Organosol im Vakuum abgedampft und der kolloide Metall-Rückstand durch Wasserstoff-Entwicklung ermittelt. Aus Eichkurven läßt sich für jede Wasserstoffmenge der zugehörige Alkali-Metall-Gehalt ablesen. Das Verfahren ist ein Schnellvetrfahren.

Notes: Zusammenfassung Die Dichten von ungemahlener, in der Schwingmühle gemahlener und rekristallisierter Zellulose wurden gemessen. Die Dichte von Zellulose vermindert sich beim Mahlen von 1,558 (Baumwolle) bzw. 1,521 (Zellwolle) auf 1,509 und steigt nach dem Benetzen mit Wasser (von 200 und 1000) oder nach dem Erhitzen auf 1800 wieder auf 1,520–1,536 an. Aus diesen Dichten ergeben sich unter Zugrundelegung der Dichte von kristalliner und der experimentell und rechnerisch abgeleiteten Dichte von amorpher Zellulose quantitative Angaben über den Ordnungszustand der verschiedenen Zellulosepräparate. Der prozentuale Anteil an kristallinen Bereichen beträgt danach bei Baumwolle 71%, bei Zellwolle 35%, bei gemahlener Zellulose 22—24% und bei rekristallisierter Zellulose 33–49%. (Fehlergrenze ± 4%). Durch Rekristallisation von gemahlener Zellulose läßt sich der Kristallinitätsgrad der Hydratzellulose bis zu 14% über den Wert bei normaler Zellwolle steigern. Aus der Differenz der Raumbeanspruchung von ungemahlener und gemahlener Zellulose wird der Verformungsweg der Moleküle beim Mahlen und die Verformungsspannung abgeschätzt.

Notes: Zusammenfassung Es wird em Verfahren angegeben, das gestattet, den Hagenbachfehler im Ostwaldviskosimeter beim Messen der relativen (und damit auch der spezifischen) Viskosität von kolloiden Lösungen zu eliminieren. Danach ist es möglich, bei betrieblichen Polymerisationsgradbestimmungen mit relativ weiten Kapillaren zu arbeiten. Alle von der Durchlaufzeit abhängigen Fehler, mit Ausnahme von dem einer möglichen Strukturviskosität, werden vermieden, wenn man die Durchlaufzeit des reinen Lösungsmittels durch die Kapillare nicht direkt mißt, sondern aus Messungen mit Newtonschen Flüssigkeiten errechnet, deren (bekannte) Zähigkeit ungefähr gleich ist der Zähigkeit der zu messenden kolloiden Lösung. Die so berechnete Durchlaufzeit wird als „reduzierte Durchlaufzeit des reinen Lösungsmittels“ bezeichnet. Sie ändert sich i. a. mit der relativen Viskosität der zu messenden Lösung. Es wird jedoch an einem Beispiel gezeigt, daß diese Änderung in den in Frage kommenden Viskositätsintervallen kleiner als 1% des Wertes der mittleren reduzierten Durchlaufzeit ist. Die reduzierten Werte sind immer kleiner als die am reinen Lösungsmittel direkt gemessenen (im Beispielsfall um 7%) Die über die reduzierten Werte [nach Gleichung (2)] gewonnenen spezifischen Viskositäten einer Konzentrationsreihe folgen i. a. mit sehr guter Genauigkeit der Schulz-Blaschkeschen Konzentrationsfunktion. Es ist also möglich, die niedrigen Konzentrationen, bei denen ein zu hohes Geschwindigkeitsgefälle und damit Strukturviskositätserscheinungen auftreten können, zu vermeiden und den limη spez c für c→ 0 aus Meßwerten an höher konzentrierten Lösungen nach der Schulz-Blaschkeschen Gleichung zu berechnen.

Notes: Zusammenfassung Ein prismatisches Gefäß wird durch eine Glasplatte in zwei Räume geteilt und in die Glasplatte eine Membran gekittet (z. B. Glasfilterplatte). In die eine Hälfte dieses Gefäßes wird eine Dipol-, in die andere Hälfte eine dipolfreie Flüssigkeit gegossen, so daß ein hydrostatisches Gleichgewicht entsteht. Infolge gegenseitiger Osmose verschwindet langsam die Niveaudifferenz. Wird in beide Hälften je eine Elektrode eingesetzt und einige tausend Volt Wechselspannung angelegt, so verändert sich die Erscheinung der Osmose wesentlich. Je nach der Art der Dipol-Flüssigkeiten steigt die eine Seite wesentlich. Zur Erklärung werden ponderomotorische Wirkungen des Feldes auf die Dipole und Veränderungen des Assoziationszustandes herangezogen.

Notes: Summary Films of polyethylene terephthalate drawn near the glass transition temperature show evidence of the development of stress-induced morphological alteration (referred to the amorphous, unoriented form) as deduced from observed initial increases in permeability and decreases in apparent permeation activation energy for oxygen. The respective values of $$\bar P$$ and $$E_{\bar P}$$ for the smaller molecule, helium, are less affected over the same range of film elongations. A simple two-group transport model of the polymer microstructure suffices to explain the data and electron micrographs reveal that an unusual type of crystalline phase, apparently the result of stretching nearT g , is the origin of the low activation energy pathways, leading to the observed diffusional enhancement for oxygen.

Notes: Zusammenfassung Es wird über Messungen der Gasdurchlässigkeit von gummielastischen Werkstoffen für Stickstoff berichtet. Der Gasdurchtritt von Stickstoff durch gummielastische Materialien ist ein Permeations- oder Lösungsdiffusionsvorgang. Die Theorie der Permeation wird dargelegt, und zwei Methoden zur Auswertung von Permeationsmessungen werden angegeben. Nach Beschreibung der Meßanordnung wird an Hand von einigen grundsätzlichen Messungen der Gasdurchlässigkeit von gummielastischen Werkstoffen für Stickstoff gezeigt, daß es sich hier tatsächlich um einen Lösungsdiffusionsvorgang handelt; d. h. dasFicksche Diffusionsgesetz und dasHenrysche Löslichkeitsgesetz sind erfüllt, und die Diffusion ist der geschwindigkeitsbestimmende Vorgang. Die Betrachtung der Temperaturabhängigkeit der Permeation zeigt, daß man für Diffusionskoeffizient, Löslichkeitskoeffizient und Permeationskoeffizient jeweils eine Aktivierungsenergie angeben kann. Meßergebnisse, die an einer Vielzahl von gummielastischen Werkstoffen erhalten wurden, werden mitgeteilt.