scispace - formally typeset
Search or ask a question

Showing papers by "Imperial College London published in 1970"


Journal ArticleDOI
TL;DR: In this article, it was pointed out that the spectra of X-ray induced fast photoelectrons from metal should have a characteristic skew line shape resulting from Kondo-like many-electron interactions of the metallic conduction electrons with the accompanying deep hole in the final state.
Abstract: It is pointed out that the spectra of X-ray induced fast photoelectrons from metal should have a characteristic skew line shape resulting from Kondo-like many-electron interactions of the metallic conduction electrons with the accompanying deep hole in the final state. The same line shape should also occur for the discrete line spectra of X-rays emitted from metals. This mechanism could account for the well-known asymmetries observed for K alpha lines.

1,773 citations


Journal ArticleDOI
TL;DR: In this article, an examination of the formation and development of shear zone structures on microscopic scale in the shear box test, intermediate scale in Riedel experiment, and regional scale in earthquake fault is made.
Abstract: An examination is made of the formation and development of shear zone structures on (1) the microscopic scale in the shear box test, (2) an intermediate scale in the Riedel experiment, and (3) the regional scale in the earthquake fault. On the basis of the resistance to shear, three structural stages are chosen for detailed study: the peak structure occurring at peak shearing resistance, the post-peak structure occurring after peak shearing resistance, and the residual structure occurring at residual shearing resistance. Most of the similarities in structure between the different scales at each of these stages are interpreted in terms of the mechanical properties of the material, the Coulomb failure criterion, and the kinematic restraints inherent in the type of deformation. Other similarities which are not as yet understood are described and suggested as topics for future research.

1,042 citations


Journal ArticleDOI
TL;DR: In this paper, the presence of the edge of a half plane in a turbulent fluid results in a large increase in the noise generated by that fluid at low Mach numbers, and the farfield sound has the same features as would be predicted by geometrical acoustics.
Abstract: The presence of the edge of a half plane in a turbulent fluid results in a large increase in the noise generated by that fluid at low Mach numbers. The parameter which is important is the product then the farfield sound has the same features as would be predicted by geometrical acoustics. The edge does not produce any significant sound amplification.

898 citations


Journal ArticleDOI
19 Dec 1970-Nature
TL;DR: It seems to be a neglected question whether the harm delivered to an adversary is always merely an unfortunate consequence of adaptations for survival, and whether such harm ever be adaptive in itself.
Abstract: INCIDENTS in which an animal attacks another of the same species, drives it from a territory, or even kills and devours it are commonplace. They may be described as examples of biological selfishness. The effect consists of two obvious parts: the gains (in fitness) of the victor and the losses of the victim. Attempts to secure the gains are easily understood to be adaptive: this is the fundamental response to what Darwin called the “struggle for existence”. But, considering the more controversial catch-phrase of evolutionary theory—“the survival of the fittest”—it seems to be a neglected question whether the harm delivered to an adversary is always merely an unfortunate consequence of adaptations for survival. Could such harm ever be adaptive in itself ? Or nearer, to the possibility of a test, would we ever expect an animal to be ready to harm itself in order to harm another more ? Such behaviour could be called spite. Is it ever observed ?

806 citations


Journal ArticleDOI
TL;DR: In this article, the transfer of heat and momentum by motion on the scale of cyclone waves and long waves is deduced from a knowledge of their mechanics, which is independent of notions of mixing but is similar to that for non-isotropic diffusion.
Abstract: The transfer of heat and momentum by motion on the scale of cyclone waves and long waves is deduced from a knowledge of their mechanics. The law of horizontal transfer of entropy is independent of notions of mixing but is similar to that for non-isotropic diffusion. The law accurately represents the annual variation of heat-flux in the Northern Hemisphere. Perturbation theory suggests realistic spatial variations for the transfer and provides a rational basis for calculating transfer coefficients which can then be used to find the flux of other conservative quantities. Most importantly the Equatorward flux of potential vorticity is well defined and is shown to determine the horizontal flux of momentum uv. The mean surface winds, and the mean meridional circulation (which is seen to be frictionally driven) are then determined. A model of the general circulation is defined by these properties, and this is integrated analytically for a simplified case and compared with motion observed in the Gulf Stream, the mesosphere, and dishpan experiments as well as the troposphere.

458 citations


Journal ArticleDOI
TL;DR: The study of the Anatolian fault zone shows that major earthquake sequences associated with faulting have been occurring in the zone since historical times with periods of quiescence of 150 years as discussed by the authors.

450 citations


Journal ArticleDOI
TL;DR: In this paper, a structural analysis of the fractures formed in the fault zone associated with the Dasht-e Bayaz earthquake of August 31, 1968 is presented, which is compatible with a predominant movement along the east-west lineament, followed by stress readjustments along the WNW-ESE lineament.
Abstract: A structural analysis is presented of the fractures formed in the fault zone associated with the Dasht-e Bayaz earthquake of August 31, 1968. The segment of the fault zone studied in detail here is 25 km long, 2 to 3 km wide, and located in the Quaternary sediments of the Nimbluk Valley. The maximum relative displacements ohserved in the fault zone (up to 450 cm left-lateral and 250 cm vertical) are concentrated in an east-west principal displacement zone 2 to 100 m wide. This zone is in turn, on a larger scale, composed of en echelon shear zones. The fault zone contains also many small fracturesdispersed throughout the area and reflecting, to a certain extent, the dominant trends of the principal displacement zone. Both on the scale of the whole fault zone and on the larger scale of the principal displacement zone, the structures are characteristic of a simple shear type of deformation. Their sense of movement and initial directions can be interpreted in terms of the Coulomb failure criterion applied to a material with an angle of shearing resistance of 35 to 40. The analysis also shows that the Nimbluk Valley contains many fault lineaments that extend into the mountains around the valley- In many places the cast-west principal displacement zone follows very precisely one of these lineaments. Evidence of fault reactivation is also found on another important lineament that crosses the principal displacement zone in a WNW-ESE direction. The earthquake fracture pattern in the Nimbluk Valley is compatible with a predominant movement along the east-west lineament, followed by stress readjustments along the WNW-ESE lineament.

359 citations


Journal ArticleDOI
TL;DR: The types of discontinuity which can occur in a magnetohydrodynamic fluid with anistotropic pressure are discussed in this article, and rules are given for the identification of the type of discontinuities together with equations to determine their orientation and velocity.

343 citations


Journal ArticleDOI
TL;DR: There was a statistically significant correlation between the stiffness, expressed as the creep modulus, and the total glycosaminoglycan content and the correlation between stiffness and collagen content was considerably less significant.

328 citations


Journal ArticleDOI
TL;DR: The steady state solution of the non-linear equation with both damping and dispersion is examined in the phase plane in this paper, where an averaging technique is used to obtain an oscillatory asymptotic solution.
Abstract: The steady-state solution of the non-linear equation \[ h_t + hh_x + h_{xxx} = \delta h_{xx} \] with both damping and dispersion is examined in the phase plane. For small damping an averaging technique is used to obtain an oscillatory asymptotic solution. This solution becomes invalid as the period of the oscillation approaches infinity, and is matched to a straightforward expansion solution. The results obtained are compared with a numerical integration of the equation.

318 citations



Journal ArticleDOI
TL;DR: Pressure drop and distribution of resistance within the lower airways on inspiration are predicted, from the theory developed earlier, for a wide range of flow rates using a symmetrical rigid model of the anatomy of the bronchial tree based upon data from lungs fixed at 75 % TLC.

Book ChapterDOI
TL;DR: In this paper, the effect of pressure on the magnitudes of a and b, where, b and a are constants of the Elovich Equation, is discussed, and the effects of pressure in a constant-volume system even over a large pressure decrease.
Abstract: Publisher Summary The Elovich Equation has a wide applicability in representing rates of adsorption and desorption. This chapter discusses the effect of pressure on the magnitudes of a and b, where, a and b are constants of Elovich Equation. The rate of adsorption decreases exponentially as the amount adsorbed increases. Hence, it is difficult to detect experimentally the effects of pressure in a constant-volume system even over a large pressure decrease. Pressure effects are best tested by abruptly changing the pressure during the course of adsorption. The slow introduction of hydrogen onto ZnO causes a considerable increase of the rate of adsorption compared with that obtained subsequent to rapid additions of gas. The Elovich equation may be used as a basis for a quantitative interpretation of rates of adsorption and desorption both from the single-gas phase and from binary mixtures.

Journal ArticleDOI
TL;DR: Using a combined distribution containing the component models as special cases, statistics are developed for testing for departures from one model in the direction of another and for testing the hypothesis that all models fit the data equally well.
Abstract: [Read before the ROYAL STATISTICAL SOCIETY at a meeting organized by the RESEARCH SECTION on Wednesday, May 13th, 1970, Professor J. DURBIN in the Chair] SUMMARY It is desired to determine which of several alternative models adequately describe the data. The properties of a combined distribution containing the component models as special cases are investigated. Using this distribution, statistics are developed for testing for departures from one model in the direction of another and for testing the hypothesis that all models fit the data equally well. The relationship with other procedures is investigated. Examples are given of the use of the method, especially when there are two component models belonging to separate parametric families.

Journal ArticleDOI
31 Jan 1970-Nature
TL;DR: The relationship between annual production and annual respiration in kilocalories per m2 per year for terrestrial animal populations is re-examined taking into account aquatic and marine animals not considered by Engelmann and correcting a number of minor errors.
Abstract: ENGELMANN1 has examined the relationship between annual production and annual respiration in kilocalories per m2 per year for terrestrial animal populations. We have re-examined this relationship in the light of a large number of further studies, taking into account aquatic and marine animals not considered by Engelmann and correcting a number of minor errors in his article, and we have tried to explain several features of the relationship in terms of the life histories of the species investigated.

Journal ArticleDOI
TL;DR: Experiments on the precursor of 1-phenylpropan-2-one occurring in rabbit urine suggest that it might be the enol sulphate of the ketone, which was found in human and greyhound urine after acid hydrolysis.
Abstract: 1. The fate of [(14)C]amphetamine in man, rhesus monkey, greyhound, rat, rabbit, mouse and guinea pig has been studied. 2. In three men receiving orally 5mg each (about 0.07mg/kg), about 90% of the (14)C was excreted in the urine in 3-4 days. About 60-65% of the (14)C was excreted in 1 day, 30% as unchanged drug, 21% as total benzoic acid and 3% as 4-hydroxyamphetamine. 3. In two rhesus monkeys (dose 0.66mg/kg), the metabolites excreted in 24h were similar to those in man except that there was little 4-hydroxyamphetamine. 4. In greyhounds receiving 5mg/kg intraperitoneally the metabolites were similar in amount to those in man. 5. Rabbits receiving 10mg/kg orally differed from all other species. They excreted little unchanged amphetamine (4% of dose) and 4-hydroxyamphetamine (6%). They excreted in 24h mainly benzoic acid (total 25%), an acid-labile precursor of 1-phenylpropan-2-one (benzyl methyl ketone) (22%) and conjugated 1-phenylpropan-2-ol (benzylmethylcarbinol) (7%). 6. Rats receiving 10mg/kg orally also differed from other species. The main metabolite (60% of dose) was conjugated 4-hydroxyamphetamine. Minor metabolites were amphetamine (13%), N-acetylamphetamine (2%), norephedrine (0.3%) and 4-hydroxynorephedrine (0.3%). 7. The guinea pig receiving 5mg/kg excreted only benzoic acid and its conjugates (62%) and amphetamine (22%). 8. The mouse receiving 10mg/kg excreted amphetamine (33%), 4-hydroxyamphetamine (14%) and benzoic acid and its conjugates (31%). 9. Experiments on the precursor of 1-phenylpropan-2-one occurring in rabbit urine suggest that it might be the enol sulphate of the ketone. A very small amount of the ketone (1-3%) was also found in human and greyhound urine after acid hydrolysis.

Journal ArticleDOI
TL;DR: In this paper, the Percus-Yevick hard-sphere radial distribution function, g(R), for R ˇ-5σ is analyzed in terms of complex variables.
Abstract: Explicit analytical expressions, written in terms of complex variables and suitable for rapid computer evaluation, are presented for the Percus-Yevick hard-sphere radial distribution function, g(R), for R ˇ- 5σ. Some effects of truncating g(R) to unity past R = 5 σ are discussed.

Journal ArticleDOI
01 Aug 1970-Nature
TL;DR: It is demonstrated conclusively that dried bone exhibits piezoelectric properties, by direct observation of electrical potentials generated when a dried specimen of bone is stressed.
Abstract: FUKADA and others1–4 have demonstrated conclusively that dried bone exhibits piezoelectric properties, by direct observation of electrical potentials generated when a dried specimen of bone is stressed. The nature and source of the electrical potentials obtained from bone when it is stressed in vivo interested us, and we have investigated the general electrical properties of wet bone.

Journal ArticleDOI
TL;DR: It appears that the hedgehog and ferret are like the dog in respect to their metabolism of benzoic acid, and the Indian fruit bat produced only traces of hippuric acid and possibly has a defect in the glycine conjugation of benzosic acid.
Abstract: 1. The urinary excretion of orally administered [(14)C]benzoic acid in man and 20 other species of animal was examined. 2. At a dose of 50mg/kg, benzoic acid was excreted by the rodents (rat, mouse, guinea pig, golden hamster, steppe lemming and gerbil), the rabbit, the cat and the capuchin monkey almost entirely as hippuric acid (95-100% of 24h excretion). 3. In man at a dose of 1mg/kg and the rhesus monkey at 20mg/kg benzoic acid was excreted entirely as hippuric acid. 4. At 50mg/kg benzoic acid was excreted as hippuric acid to the extent of about 80% of the 24h excretion in the squirrel monkey, pig, dog, ferret, hedgehog and pigeon, the other 20% being found as benzoyl glucuronide and benzoic acid, the latter possibly arising by decomposition of the former. 5. On increasing the dose of benzoic acid to 200mg/kg in the ferret, the proportion of benzoyl glucuronide excreted increased and that of hippuric acid decreased. This did not occur in the rabbit, which excreted 200mg/kg almost entirely as hippuric acid. It appears that the hedgehog and ferret are like the dog in respect to their metabolism of benzoic acid. 6. The Indian fruit bat produced only traces of hippuric acid and possibly has a defect in the glycine conjugation of benzoic acid. The main metabolite in this animal (dose 50mg/kg) was benzoyl glucuronide. 7. The chicken, side-necked turtle and gecko converted benzoic acid mainly into ornithuric acid, but all three species also excreted smaller amounts of hippuric acid.

Journal ArticleDOI
TL;DR: In this paper, the authors used a 15.5 m multiple-reflection cell, giving total path lengths up to 500 m, and a high-resolution (1−2 cm−1) grating spectrograph.
Abstract: All published work on the water-vapour continuum in the region 8 μ to 50 μ is reviewed in the light of some new experimental results in the 11 to 21 -μ region. This new work employed a 15.5 m multiple-reflection cell, giving total path lengths up to 500 m, and a high-resolution (1–2 cm−1) grating spectrograph. Control of temperature (20–40°C), and water-vapour partial pressure (3–35 mb) allowed simulation of tropospheric conditions and their extension to rather higher humidities, but the total pressure could not be varied from atmospheric. The results suggest that two mechanisms of absorption are involved. One of them is almost certainly the foreign-broadening of water-vapour lines and it is responsible for most of the continuum absorption noted by previous workers. The origin of the other is not clear; it gives rise to absorption which increases with partial water-vapour pressure, e, equalling the foreign-broadened component at e ∼ 15 mb. This behaviour was first reported by Bignell, Saiedy and Sheppard (1963) who then attributed it to self-broadening of H2O lines. However, the present more sensitive work casts doubt on this interpretation because the absorption is found to have a negative temperature dependence of 2 per cent per °C over the range 21° to 45°C, which is greater than that of any water-vapour line. Absorption of the same type, though weaker, is present near 4 μ. Reinterpretation of previous open-air measurements in atmospheric conditions ranging from warm and damp to cold and dry shows that the systematic differences they exhibit might be a manifestation of the new absorption. No firm explanation can be given, but the possibility of continuum absorption by the recently reported water dimer molecule (H2O)2 should be investigated.

Journal ArticleDOI
TL;DR: The power spectrum of the intensity fluctuations in a random speckle pattern is derived in a simplified manner for coherent illumination in this article, and the effect of the power spectrum on the measured signal-to-noise ratio is discussed.
Abstract: The power spectrum of the intensity fluctuations in a random speckle pattern is derived in a simplified manner for coherent illumination. The effect of the power spectrum on the measured signal-to-noise ratio is discussed, and some preliminary measurements of the power spectrum are presented. The power spectrum of the intensity fluctuations for partially coherent illumination is derived for the special case of an aberration-free system, using quadratic filter theory.

Journal ArticleDOI
TL;DR: It is suggested that the myelin-like fraction is a stage in the formation of compact myelin from glial plasma membrane from developing rat brain.
Abstract: 1. A myelin-like membrane fraction was isolated from developing rat brain by a new method. 2. The chemical composition and morphology of the fraction are described. 3. The myelin-like fraction is similar to myelin in characteristic enzyme activity but differs in the absence of basic protein and cerebrosides. No similarity to other subcellular fractions was observed. 4. It is suggested that the myelin-like fraction is a stage in the formation of compact myelin from glial plasma membrane. 5. `Early' myelin consists of the myelin-like and compact myelin fractions from developing brain.

Journal ArticleDOI
25 Jul 1970-Nature
TL;DR: The ability of serum from men with gonorrhoea of less than 3 days duration to kill the gonococci present in the urethral exudate and the same organism after subculture is tested.
Abstract: MAN is uniquely susceptible to gonorrhoea, but antibodies present in normal human sera are bactericidal for cultured gonococci1–3. The ineffectiveness of these antibodies in the natural infection may be explained if gonococci growing in the host possess a factor, perhaps a surface antigen, which protects the organism from the bactericidal action of serum. There is some evidence that Neisseria gonorrhoeae loses virulence factors during growth in vitro because enormous doses of cultured gonococci were required to infect volunteers4,5 while organisms recovered from the resulting urethral discharges exhibited enhanced virulence6. Another, less likely, suggestion is that gonococci only infect individuals lacking bactericidal antibodies to the strain concerned. To distinguish between these possibilities we have tested the ability of serum from men with gonorrhoea of less than 3 days duration to kill the gonococci present in the urethral exudate and the same organism after subculture.

Journal ArticleDOI
TL;DR: There was a rise in calcium and phosphate absorption from the gut in the normal subjects and to about the same extent in the patients with chronic renal failure and there was a fall in urinary phosphate excretion.
Abstract: 1. Two normal subjects and ten patients with chronic renal failure were given 15 or 20 g of calcium carbonate in the morning and 5·6 or 8·4 g of calcium phosphate in the evening for 13–41 days. 2. During the high calcium and phosphate intake there was a rise in calcium and phosphate absorption from the gut in the normal subjects and to about the same extent in the patients with chronic renal failure. 3. The calcium and phosphate balances became positive while there was a rise in plasma calcium and a fall in plasma phosphate. There was also a fall in urinary phosphate excretion.

Journal ArticleDOI
TL;DR: In this paper, a plot of critical wind speed against the direction of the wave fronts shows a cusp, and the onset of instability will correspond to the cusp and the nature of the waves can be predicted from this.
Abstract: The behaviour of continuous pulsations pc 2–5 observed on the ground has been known for some time. They seldom occur at night, their amplitudes generally increase towards the auroral zones and the sense of rotation of their polarisation often agrees with surface waves on the magnetopause. Recently ULF sonagrams for middle latitudes have shown systematic behaviour and dominant periods. Theoretical study of normal modes for symmetrical models is also well established. If the wave depends on longitude φ like e imφ , modes with large m are quasi-transverse and these are likely to be excited and will be emphasised. The Kelvin-Helmholtz instability has recently been studied in a general formulation. For given fields and plasma properties on both sides of the boundary, a plot of critical wind speed against the direction of the wave fronts shows a cusp, meaning that for most directions of the wind the onset of instability will correspond to the cusp and the nature of the waves can be predicted from this. Almost circularly polarised waves are predicted confirming an earlier heuristic suggestion. Magnetic data from Explorer 33 shows rather irregular disturbance near the magnetopause, but an integration designed to show the sense of rotation of the polarisation shows clear agreement. The disturbance outside the magnetopause also shows the predicted polarisation, indicating that a substantial part of it must be due to surface waves, whereas previously it was believed to be the turbulence of the magnetosheath. Bounce resonance has also been invoked to excite ULF waves, particularly those observed at the geostationary orbit, which may also correspond to pg at the ground. They are remarkably regular and quite strictly transverse, suggesting large m. Energetic particles may then see a higher frequency as a result of their drift. A simple picture of the exchange of energy is obtained using a frame rotating with the wave and it is seen that the wave can be driven by a spatial gradient in the energetic particles. The most important mechanism is due to the tilting of the field lines and the growth rate can be large. The reflection by the ionosphere requires further study.

Journal ArticleDOI
TL;DR: Electrical pulses of alternating polarity applied to suspensions of synaptosomes from cerebral cortex in Krebs-Ringer phosphate caused a large increase in respiratory and glycolytic rates and a parallel change in ion and amino acid content.

Journal ArticleDOI
TL;DR: A theory of the factors governing dissipation is formulated which agrees with the experimental results and can be used to predict the overall pressure drop in a branched system provided that kinetic energy changes are included.

Journal ArticleDOI
TL;DR: In this paper, a non-linear theory was used to calculate the profile of the waves on the surface of the jet at breakup, and also to predict the volume of the main and satellite drops.

Journal ArticleDOI
TL;DR: The glycoprotein was shown to possess a high half-cystine content of 1 per 11-12 amino acid residues, which has been confirmed by performic acid oxidation and S-alkylation with iodoacetate andiodoacetamide.
Abstract: 1. A revised amino acid and carbohydrate composition of human Tamm–Horsfall glycoprotein is presented. 2. No significant differences were obtained in the amino acid composition of Tamm–Horsfall glycoprotein isolated from patients with cystic fibrosis. 3. The glycoprotein was shown to possess a high half-cystine content of 1 per 11–12 amino acid residues, which has been confirmed by performic acid oxidation and S-alkylation with iodoacetate and iodoacetamide. No thiol groups were detected in the glycoprotein. 4. Treatment of the glycoprotein with 0.5m-sodium hydroxide at 4°C for 2 days did not release heterosaccharide material, which suggests that the predominant carbohydrate–protein linkages present are not of the O-glycosidic type. 5. No N-terminal amino acid was detected in the glycoprotein.

Journal ArticleDOI
TL;DR: In this article, the acoustic scattering properties of a semi-infinite compliant plate immersed in turbulent flow are considered in the context of Lighthill's theory of aerodynamic noise, where turbulent eddies are replaced by a volume distribution of quadrupoles, and the reciprocal theorem is used to transform the quadrupole scattering problem into one of the diffraction of a plane acoustic wave.
Abstract: The acoustic scattering properties of a semi-infinite compliant plate immersed in turbulent flow are considered in the context of Lighthill's theory of aerodynamic noise The turbulent eddies are replaced by a volume distribution of quadrupoles, and the reciprocal theorem used to transform the quadrupole scattering problem into one of the diffraction of a plane acoustic wave This problem is solved by the Wiener–Hopf technique for the case when elastic forces in the plate are negligible, so that a local impedance condition relates the plate velocity to the pressure difference across the plate Strong scattering of the near-field into propagating sound occurs when certain types of quadrupole lie sufficiently close to the plate edge, and we derive explicit expressions for the scattered fields in various cases When fluid loading effects are small, and the plate relatively rigid, the results of Ffowcs Williams & Hall (1970) are recovered, in particular the U5 law for radiated intensity A quite different behaviour is found in the case of high fluid loading, when the plate appears to be relatively limp The radiated intensity then increases with flow velocity U according to a U6 law In aeronautical situations, surface compliance is negligible in its effect on the scattering process, and the U5 law must then apply provided the surface is sufficiently large On the other hand, the effect of appreciable surface compliance is to greatly inhibit the near-field scattering from the surface edge This weaker scattering is likely to be observed in underwater applications, where fluid loading effects are generally so high as to render unattainable the condition for a plate to be effectively rigid