Search

There are many submarine sand waves on the bottom of the Bisan Strait at the Seto Inland Sea and they obstruct navigation. This is a report of the investigation which has been conducted to study the mechanism of sand wave formation at Inosakinotsugai in the Bisan Strait. Soundings, collection of bottom materials and observation of tidal currents constitute this investigation. The following items have been made clear through this investigation:1) Formation of sand waves is greatly influenced by sand bank.2) Submarine sand waves are dunes. Those scales are approximately equal to the values calculated by Yalin's formula.3) When tidal currents flow aground onto the sand bank, intensity of turbulence increases and two prominent eddies appear. After they pass over the sand bank, intensity of turbulence decreases and those eddies disappear.

In a ferromagnetic alloy the dependence of the coercive force HC and the initial susceptibility χa on the size and the number of non-magnetic inclusions has been experimentally investigated. Cylindrical single crystals with their rod axis parallel to the magnetic soft direction have been used as specimens. The material PE 16 is a commercial Ni-based alloy which by suitable heat treatment precipitates spherical, non-magnetic particles of Ni3(Al, Ti), which do not strain the matrix. The dependence of HC and χa on the particle diameter d is in agreement with theoretical predictions. The relation between these two parameters and the volume fraction v cannot be described by the corresponding equations. This discrepancy is probably due to the fact that the Bloch-Wall geometry within the specimen does not remain constant with varying v. The product HC · χa has been found independent of v and d. An einer ferromagnetischen Legierung wurde die Abhangigkeit der Koerzitivfeldstarke HC und der Anfangssuszeptibilitat χa von der Grose und Anzahl nichtmagnetischer Ausscheidungen experimentell untersucht. Es wurden zylindrische Einkristalle verwandt, deren Stabachse in die magnetisch weiche Richtung orientiert war. Ausgangsmaterial war die auf Ni basierende Legierung PE 16, die bei geeigneter Warmebehandlung kugelformige, nicht-magnetische Teilchen der Zusammensetzung Ni3(Al, Ti) ausscheidet. Die Teilchen verspannen die Matrix nicht. Die gemessene Abhangigkeit von HC und χa vom Teilchendurchmesser d ist in Ubereinstimmung mit theoretischen Beziehungen. Ein entsprechender Zusammenhang zwischen diesen beiden Grosen und dem ausgeschiedenen Volumenbruchteil v konnte nicht bestatigt werden. Vermutlich andert sich mit v auch die Blochwand-Geometrie innerhalb der Probe. Das Produkt HC · χa ist unabhangig von v und d.

The plasma focus device, a form of linear pinch discharge, produces an intense x-ray and neutron (D2) burst from a magnetically heated dense plasma. Rapidly changing magnetic fields at pinch time generate large axial electric fields which accelerate electrons and ions. In the experiments reported here the x-ray production during the plasma pinch of a 96 kilojoule (at 20 kV) plasma focus device was measured.The purpose of these experiments was to evaluate the energy in accelerated electrons in the plasma focus device and to learn how to enhance these electron hursts. Well focused, megampere electron beams at a few hundred kilovolts, lasting less than 10 nanoseconds have applications in fusionable pellet heating experiments. (1) X-rays were monitored to evaluate these electron bursts using a defocusing bent crystal spectrometer, doubly diffused silicon (PIN) detectors, with Ross filters, thermoluminescent dosimeters (TLDs) with filters, and x-ray pinhole photography.Thermoluminescent dosimeters indicated maximum x-ray yields of 140 joules above 3 keV at 57.3 kilojoules stored energy (16 kV) for a conversion efficiency to x-rays of 0.2%. 40 joules are above 60 keV and 15 joules above 80 keV. The hard x-ray pulse typically rises in 3 ns and frequently has a pulse width less than 10 ns. The low energy x-ray spectrum consists almost entirely of lines from the high Z anode insert, and the high energy spectrum is characteristic of a nonthermal power law distribution with an exponent of 2.2 ± 0.8. Peak hard x-ray production is obtained at 1 torr deuterium in contrast to peak neutron production (3 x 1010) at 5 torr. The addition of argon reduces total x-ray yield and increases the relative fraction of soft x-rays.These measurements suggest that the plasma focus produces 1200 joules of electrons with an average energy of 150 keV, in 10 nanoseconds with a stored energy of 57.3 kilojoules. This is a power of 1.2 × 1011 watts and power density of 1.5 × 1013 watts cm−2.

On vérifie en détail les calculs théoriques d'un article précédent sur les formes inhabituelles de courbes de résonance en champ de radiofréquence inhomogène. Les expériences sont réalisées sur du gaz de 3He orienté par pompage optique. Les différents effets prévus sont observés et étudiés (forme des deux courbes, large et étroite, différents types de déplacement des positions de la résonance, etc...). Ces expériences fournissent une mesure du coefficient de self-diffusion gazeux de 3He à 300 K : D33 = 1 440 ± 80 cm2 s-1 à 1 torr.

The Kakutani equation is rewritten in retaining the relative weights of terms: non-linearlity, dispersion and the effect of unevenness of bottom.Laws of shoaling are derived from the equation. Line...

The Kakutani equation is extended to include the effect of the variable width of channel, which is important in such a practical problem as refraction.Assuming that the wave profile is that of cnoidal waves and that this profile is maintained throughout the travel, a law of shoaling is derived.A comparison with experimental data shows that the present theory describes very well the shoaling for gHT2/d2>30, while for gHT2/d2

2014 Plastic fracture mechanics can allowed low and middle strength steel’s selection in order of fracture safe design. It takes in consideration, critical crack tip opening displacement (C. O. D.). Critical crack tip opening displacement and overall strain throught a defect give a linear relation ship in C. O. D.’s validity zone. We should give an experimental verification of this paint with large steel’s sheets with artificial defect and stressed in tension. Man can made calculation of critical defect size with aid of this relation and steel’s toughness of a given stress level. REVUE DE PHYSIQUE APPLIQUEE TOME 9, JUILLET 1974, PAGE La selection d’un materiau en vue de la realisation d’une construction soumise a des sollicitations complexes (par exemple un reservoir sous pression) impose aux bureaux d’etudes de se conformer a l’article 4 de l’Arrete Ministeriel du 23 juillet 1943 : « L’ouvrage ne doit pas etre fragile dans les conditions de service, ni dans les conditions de l’epreuve hydraulique. » Le declenchement d’une rupture fragile necessite l’existence des 3 conditions suivantes : la temperature de service est inferieure a une « temperature de transition » ; nous definirons cette notion de temperature de transition ulterieurement ; le niveau de contrainte est suffisamment eleve dans la region consideree de l’ouvrage ; on se trouve en presence d’un defaut dont l’acuite permet d’initier une rupture fragile. Ces trois conditions presentes simultanement risquent de produire une rupture fragile ; on est a l’abri de ce risque si l’une d’entre elles n’est pas remplie, c’est-a-dire si la temperature est assez elevee, s’il n’existe aucune contrainte ou si on constate l’absence d’entaille. On remarque l’existence d’interactions entre ces conditions, ainsi des defauts plus aigus, des contraintes en service plus elevees, augmentent la temperature a laquelle ce risque de rupture est susceptible de se produire. L’ensemble de ces 3 parametres : Temperature, contrainte et taille de defaut peut definir la tenacite d’un materiau. En fixant deux de ces parametres, on se donne un critere de ductilite car le troisieme est impose par les caracteristiques du materiau et dans une construction la rupture se produit lorsque ces trois grandeurs atteignent les valeurs critiques. Cette notion est restee et reste encore purement conceptuelle mais l’introduction recente de la mecanique des ruptures tend a lui donner une formulation. Le taux de travail maximal est fixe par le legislateur

Mechanisms for explaining the various forms of particles and radiation observed during the flash phase of solar flares are reviewed under the working hypothesis that the flash phase is the time in which electrons and to a lesser degree protons are accelerated in less than one second. A succession of such accelerations is allowed to explain longer lasting or quasi-periodic phenomena. Mechanisms capable of such acceleration are reviewed and it is concluded that first-order Fermi acceleration in a reconnecting current sheet is the most likely basic process. Such acceleration, however, gives rise to a rather narrow distribution of particle velocities along a given field line which is unstable to the production of electron plasma and ion-acoustic waves. This plasma turbulence can heat the plasma to produce soft X-rays and filter the initially narrow velocity distribution to produce a power law energy distribution. Electrons travelling inward from the acceleration region produce hard X-rays by bremsstrahlung and microwave bursts by gyro-synchrotron emission. Whereas the interpretation of X-ray spectra is relatively straightforward, the interpretation of microwave spectra is difficult because the source at low frequencies can be made optically thick by several different mechanisms.Electrons travelling further inward presumably thermalize and produce impulsive EUV and Hα emission. The theory for these emissions, although amenable to present techniques in radiative transfer, has not been worked out. Electrons travelling outward give rise to type III radio bursts by excitation of electron plasma waves and the electrons observed at the Earth. Study of the interaction of a stream of electrons with the ambient plasma shows that the electron spectra observed at the Earth do not necessarily reflect their spectrum at the acceleration region since they interact via plasma waves as well as through Coulomb collisions. The mechanisms for the conversion of plasma waves into radiation and the propagation of the radiation from its source to the observer are reviewed.

2014 A review is presented of the various kinds of energies occurring to determine the arrangement of the localised magnetic moments : the exchange energy, the magnetostatic energy, the magnetocrystalline anisotropy, the magnetoelastic effects, and the coupling energy with lattice defects. Then it results that any ferromagnetic sample divides itself spontaneously in domains of uniform magnetization with the object of decreasing the total energy of the moments system, two adjacent domains being separated by a transition region called a wall. We examine the main technics used to observe the domains and the effects of the general configuration on the magnetization processes. REVUE DE PHYSIQUE APPLIQUEE TOME 9, SEPTEMBRE 1974, PAGE Introduction. Pour analyser le comportement d’un bon nombre de materiaux magnetiques, il est souvent utile et parfois indispensable de tenir compte de l’existence des domaines magnetiques. L’expose qui suit, destine a un public de non-specialistes, se limite aux aspects consideres comme classiques. On essaie d’expliquer, le plus simplement possible, pourquoi il y a des domaines magnetiques et comment cette structure, a une echelle intermediaire entre l’echelle atomique et l’echelle macroscopique, rend compte des aspects parmi les plus originaux du comportement des materiaux magnetiques. 1. Le modele microscopique. A l’echelle atomique on peut concevoir un solide ferroou ferrimagnetique comme un assemblage regulier de moments magnetiques localises, c’est-a-dire attaches a chacun des atomes ou des ions qui composent le cristal, et caracteristiques de sa structure electronique. Toutes les influences exterieures, un champ magnetique applique par exemple, ou encore l’agitation thermique, n’entrainant que des modifications negligeables de la structure electronique ne peuvent que provoquer des rotations des moments. Toutes les proprietes d’un cristal, l’aimantation a saturation, l’hysteresis, l’aimantation remanente ne sont que le reflet des rotations des N moments atomiques qui le composent. Avec un tel modele on se trouve alors devant un probleme a 2 N degres de liberte. 2. Les differentes especes d’energie. Pour comprendre comment s’orientent les moments atomiques, il faut commencer par recenser toutes les energies mises en jeu dans un tel systeme. Nous allons suivre un expose propose initialement par C. Kittel [1]. Par ordre d’importance decroissante, on trouve : Z .1 L’INTERACTION D’ECHANGE RESPONSABLE DU FERROOU DU FERRIMAGNETISME. Deux moments magnetiques voisins tendent a s’aligner soit parallelement dans un ferromagnetique, soit antiparallelement dans un antiferromagnetique. S’il n’y avait en jeu que ce type d’interaction on observerait un alignement parfait des N moments qui composent le cristal et le moment resultant serait en permanence le moment a

In order to clarify the water particle velocity field of breaking waves on beaches, experiments were carried out for three kinds of beach slopes (1/10, 1/20 and 1/30). Neutrally buoyant particles were used as tracers to measure the velocities with a 16 mm high speed cinecamera. Since photographs of the wave profile near breaking were also taken in the same films, the change of the wave profile near breaking was also examined. It was found that vertical distributions of horizontal water particle velocities at the crest and trough phases of breaking waves on beaches cannot be explained by the finite amplitude wave theories for uniform depth. Then, they were discussed in comparison with the breaker types. As a result, it was shown that the dimensionless vertical distribution of horizontal water particle velocity at the crest phase of breaking waves is determined by the combination of the beach slope and the deep-water wave steepness.

Measurements of the electronic thermal conductivity of superconducting lead and lead-manganese-alloys are reported. The samples are quench condensed-films. The thermal conductance of lead films is in good agreement with the BRT-theory. In spite of lead-manganese perhaps being a Kondo-system the thermal conductivity of this alloy is reasonably well described by the Ambegaokar-Griffin theory. Our measurements do not agree with those on indium-manganese alloys reported by other authors.

The fluorescence characteristics of hematoporphyrin have been studied at 26°C as a function of concentration and pH. The pk values are 4.7 and 8.2 as determined in water and water-ethanol mixtures. The fluorescence spectrum consists of a peak at 625 nm and a second, less intense band at 675 nm. These emission bands are assigned to the Qy (0 → 0) and Qx(0 → 0) states. The four absorption bands in the visible region are assigned to π → π* transitions as follows: 502 nm, (1 ← 0); 536 nm, Qy (0 ← 0); 557 nm, Qx (1 ← 0); and 605 nm, Qx (0 ← 0). Corresponding excitation wavelengths include 505,540,570, and 620 nm. Polarized fluorescence is used to establish molecular association as a function of concentration. The polarization factor is used to verify the change from D2hto D4hsymmetry as a function of pH.

Waves will dissipate their energy rapidly after breaking. In this paper, the behaviors of breaking waves are discussed experimentally and theoretically. The experiments are carried out by using a composite slope consisting of an approach ramp with a 1/18 slope leading up to a horizontal surface.A new basic equation for a breaking wave is presented and the theoretical curves computed numerically have a consistent agreement with the experimental data.

The basic idea of the renormalization group is introduced and illustrative examples are presented. Emphasis is put on the application to the theory of critical phenomena. This article is prepared for pedagogical purposes. It is written at a level that a second-year graduate student in physical sciences can understand. No previous knowledge of critical phenomena or field theory is needed. We make no attempt to survey the field or cover a wide range of subjects. On the contrary, we limit the scope to the most basic aspects. We choose to elaborate at length to make the basic idea clear and the definitions precise, and to go through the examples very carefully. We feel that once these basic aspect are understood, there will be no difficulty in confronting the rapidly expanding literature on this subject.

Microclimatic modifications introduced by windbreak networks result from the primary effect of shelters on wind velocity and its vertical profile. Measurements were made near Avignon (France), in order to support theoretical conceptions about land roughness and its influence on turbulent exchanges. Wind velocity profiles between ground level and 12 m were measured simultaneously at two places, near to each other: a large airfield, which can be considered as the reference, and a small grass surface, downwind a succession of hedges about 8 m high. While wind profiles in an unprotected zone fit the classical semi-logarithmic law, profiles in a protected zone exhibit kinks, which separate two logarithmic parts. The lower part corresponds to the local scale, as shown by the roughness length which is characteristic for a grass surface. The friction velocity u∗ is reduced compared to that observed in the unprotected zone. The upper part, corresponding to the regional scale (with a roughness length about 1/10 of the shelter height) shows an increased u∗ . Windbreak effects then result in a global reduction of the horizontal component of wind velocity and a modification of momentum turbulent exchange intensity (which is reduced at the local scale and increased at the regional scale). These first measurements, which appear to support theoretical suggestions, will be later completed by a denser experimental program.

Compton-scattering cross sections of Si and Ge for $\mathrm{Cu}K\ensuremath{\alpha}$ radiation are determined by direct absolute measurement of the intensity scattered from a single crystal. Parasitic components are eliminated by an evacuated specimen chamber and by combined use of a scintillation counter and a Si(Li) solid-state detector. The contribution of the thermal diffuse scattering is subtracted by a calculation based on independently determined phonon frequecies. At large scattering angles the contribution of the Compton scattering is separated directly by the Si(Li) detector. In the case of Si, a good agreement with the Waller-Hartree theory is obtained above $\frac{sin\ensuremath{\theta}}{\ensuremath{\lambda}}=0.2$ ${\mathrm{\AA{}}\mathrm{A}}^{\ensuremath{-}1}$. The experimental values for Ge are considerably larger than the theoretical ones, particularly at small scattering angles. To explain the origin of these discrepancies theoretical calculations which allow for electron binding in the Compton process and include the effects of the band structure of Ge crystal are needed.

The Hall coefficient RH of Ge specimens with doping concentrations between 1014 acceptors and 1015 donors per cm3 is determined as a function of magnetic field (2 × 10−3 to 15 T) in the temperature range from 30 to 250 K. At temperatures below 85 K a saturation value of RH at high magnetic fields is reached for all doping concentrations which is independent of specimen orientation. Empirical rules are derived for determining the exact carrier density from Hall effect measurements at medium and low magnetic fields. In einer Serie von Germanium-Proben mit Dotierungen zwischen 1014 Akzeptoren und 1015 Donatoren pro cm3 wird der Hallkoeffizient RH in Abhangigkeit vom Magnetfeld (2 × 10−3 bis 15 T) im Temperaturintervall von 30 bis 250 K bestimmt. Bei Temperaturen unter 85 K wird unabhangig von Dotierung und Orientierung bei hohen Magnetfeldern immer ein Sattigungswert fur RH erreicht. Daher ist es moglich, Mesvorschriften zur Bestimmung der exakten Tragerdichte durch Halleffektmessungen bei mittleren und niedrigen Magnetfeldern anzugeben.

Der in Luft zugangliche Teil der Absorptionsspektra wird fur Rubidiumbromid und Kaliumjodid bei Temperaturen zwischen +220 und −253° C untersucht. Die Lage der ersten Energiestufe, gemessen in Voltmas, verschiebt sich nahezu linear mit der Temperatur. Diese Verschiebung erklart die bekannte starke Temperaturabhangigkeit des Brechungsindex der Alkalihalogenide.

The operation of a mass spectrometer equipped with a molecular beam gas sampling system is described. Polymeric ions, (CO2)n+ where n varies from two to twelve, are observed when sampling CO2 at 1 to 6.5 atm; similar polymers are found in SO2 and N2O. A possible explanation is advanced in terms of isentropic expansion in the sampling process and subsequent condensation.

Es wird das Auftreten von Spektrallinien hoher Anregungsenergie in der Lichtbogensaule bei vermindertem Druck begrundet und es werden Messungen des Intensitatsanstieges der roten Wasserstofflinie bei Druckerniedrigung mitgeteilt.

A thin Bi layer is irradiated by X-rays so thatL-Auger electrons are emitted. A magnetic lens spectrometer is used to measure the electron spectrum. Energy, transition, and relativ intensity are given for 14 lines. Under the most favourable conditions the number ofLIII ionisations is about ten times that ofLII ionisations. In this case only a small intensity ofLII-Auger electrons is superposed on theLIII-Auger spectrum. The ratiod of intensities of line groupLIIIM N to line groupLIIIM M is found by extrapolation to bed=0·46±0·02. This combined with earlier results gives anLIII-Auger yielda3= 0·64±0·04. TheLIII fluorescenc yield isω3=0·36±0·04, correspondingly. A further application of the experimental method is described.

The first part of an experimental and theoretical investigation into the feasibility of transpiration cooled combustion chambers is discussed, as well as the design and testing of two Rolls-Royce ‘Dart’ porous flame tubes. The theory of heat transfer in porous materials is briefly described and correlations for heat transfer and pressure drop-mass flow are presented for selected samples of porous metal. Experimental results are presented in which the cooling efficiency of the original ‘Dart’ splash-cooled flame tube is compared with two porous replacements constructed from sintered woven wire porous metal compacts having different permeabilities. Tests were conducted at 1 and 4 atm pressure and some selected results are compared with theoretical predictions made with and without account being taken of the effect of coolant injection on the convective heat flux. The high effectiveness of transpiration cooling is clearly demonstrated but it is also shown that the distribution of static pressure in the annulus formed between the flame tube and the casing, both longitudinally and circumferentially, plays a very important part in the design of a porous flame tube.

The Raman and infrared spectra of Na2MoO4, K2MoS4, and Cs2MoS4with92Mo and100Mo have been measured. The exact force field has been determined from these spectra. The results are compared with those obtained by using various approximation methods.

An analytical method has been developed using a spark-source mass spectrograph for rapid, routine analysis. Using an electrical detection system and reproducible sample positioning, precisions of ±3% are attained under routine conditions with an accuracy of ±7% for several elements in the NBS 460 series of iron standards. Repetitive analyses of Ag in Cu demonstrate the method can analyze trace elements in metals with accuracies approaching ±2%. Details of the electrode positioning procedure and the analytical accuracy and precision of the technique are presented.

Les bandes de la vapeur d'eau à 2,7 et I,8 μ ont été étudiées au moyen d'un spectrographe à réseau à cellule au sulfure de plomb. On a essayé d'interpréter une partie des bandes de rotation-vibration obtenues au moyen des transitions permises entre les niveaux d'énergie de la molécule dans les états (I, 0, 0) (o, o, I) (o, I, I) et l'état fondamental (o, o, o), et l'on a calculé les constantes de rotation dans les trois états (I, 0, 0) (0, 0, I) et (o, I, I).

La lumière de fluorescence émise par des atomes de néon d'une cellule C soumise à un champ magnétique et placée à l'intérieur de la cavité d'un laser à gaz est modifiée lors de l'irradiation par la raie laser λ = 6 328 Å (3s2-2p4) du néon. L'étude détaillée de ces modifications sur les raies de fluorescence émises par le niveau 2p 4 permet de vérifier les prévisions théoriques développées dans un article antérieur (2) . Elle montre, en particulier, l'importance de l'effet de cascade par émission spontanée sur la transition λ = 6 328 Å. On trouve que les temps de relaxation de la population et de l'alignement du niveau 2p4 sont très différents. Les sections efficaces de collision correspondantes ont été mesurées. De plus, on a mis en évidence un phénomène de diffusion multiple cohérente sur la raie 5 943 Å (2p4-1s5) sensible au courant de la décharge excitatrice de C.

Die Arbeit vergleicht alle im Konzentrationsbereich des latenten Bildes mit unseren physikalischen Methoden ausgefuhrten Untersuchungen uber die Photochemie der Alkalisalze einerseits, der Silbersalze andererseits. Sie stellt die vollige Identitat aller beobachteten Erscheinungen fest. Sie beseitigt vor allem eine Differenz in den elektrischen Beobachtungen: Man findet in den Silbersalzen im Gegensatz zu den Alkalisalzen schon wahrend der Entstehung des latenten Bildes eine leicht mesbare Elektrizitatsbewegung im Innern des Kristalls. Diese Elektrizitatsbewegung in den Silbersalzen ruhrt jedoch von einem an den Elementarprozes anschliesenden Vorgang her. Der Elementarprozes selbst, die Entstehung des ersten, noch atomar verteilten Reaktionsproduktes geht sowohl bei den Silberwie den Alkalisalzen ohne Elektrizitatsbewegungmeβbarer Grose vor sich. Es handelt sich in beiden Fallen um den Elektronenubergang von Anion zum Kation, also um eine Elektrizitatsbewegung in nur molekularen Dimensionen.

Es wurde die Abhangigkeit der Detonationsgrenzen und der Detonationsgeschwindigkeit vom Rohrdurchmesser fur die Systeme H2-O2-N2, H2-O2-He, H2-O2-Ar, CH4-O2 und C2H4-O2 bei Normaldruck und Zimmertemperatur in Rohren bis zu 16 mm Innendurchmesser bestimmt. Dabei ergab sich ein linearer Zusammenhang zwischen der Grenzkonzentration des Brenngases und dem reziproken Grenzdurchmesser. Eine Abhangigkeit der Detonationsgeschwindigkeit vom Rohrdurchmesser konnte dagegen im Rahmen unserer Mesgenauigkeit (∼1%) auch in unmittelbarer Nahe der Grenzen nicht beobachtet werden. –- Im Anschlus an die Messungen wurde versucht, die gefundenen Ergebnisse zu erklaren. Es zeigte sich, das die Grenzen nicht allein durch kinetische Faktoren bestimmt werden, sondern das hydrodynamische Faktoren fur die Grenzen mitverantwortlich sind. Die Behandlung der hydrodynamischen Einflusse fuhrte auf ein Randwertproblem fur die Differentialgleichungen der isentropen wirbelfreien Stromung (siehe Teil III). The dependence of the limits of detonability and of the detonation velocity on tube diameter was determined at normal pressure and room temperature in tubes up to 16 mm in internal diameter for the systems H2-O2-N2, H2-O2-He, H2-O2-Ar, CH4-O2 and C2H4-O2. A linear relation between the limiting concentration of the combustion gas and the reciprocal of the limiting diameter was found. Within the limits of accuracy of our measurements (-1%) it was not possible to observe a dependence of the detonation velocity on the diameter of the tube, even in the immediate vicinity of the explosion limit. An explanation of the results was attempted. It was found that the limits are governed not solely by kinetic factors but also by hydrodynamic factors. The treatment of the hydrodynamic effects led to a boundary value problem for the differential equations of isentropic irrotational flow (see Part 111).

Die Absorptionsbandkanten von Brom und Chlor werden ausgemessen und in ein Serienschema geordnet. Die Temperaturveranderlichkeit des Spektrums wird untersucht und ein Zusammenhang zwischen der Lage der Absorptionsmaxima und der Natur der Bindung nachgewiesen. Aus den Bandenkonvergenzstellen und aus Daten der Atomspektren werden die Dissoziationswarmen mit groser Genauigkeit berechnet.

On donne les résultats de mesures de sections efficaces de formation de plusieurs isotopes du thorium et de l'actinium, par bombardement de Th 232 par des protons de 155 MeV. Ces sections sont également calculées en admettant un processus de spallation en trois étapes : interaction directe, évaporation de neutrons de compétition fission-évaporation dans les noyaux éxcités. On examine les valeurs de Γn/Γf et on compare avec les résultats expérimentaux.

A study is described which attempts to obtain information about the vertical correlation of ocean currents at frequencies higher than inertial. Current velocity and temperature data for sensor separations of 4–12 m were taken with a mooring at ‘Site D’. The coherence and phase spectra for velocity component pairs reveals that motions are rotational at low frequencies. A cut-off frequency exists above which coherence drops to low values. The limiting frequency coincides with the minimum Väisälä frequency of the total water column. These cross-spectral properties support the assumption that the motion in this frequency range is governed by internal wave dynamics. The coherence and phase spectra of temperature pairs indicate that a field of temperature structure is superimposed on the mean field which is weakly correlated to the field of motion.

SUMMARY Lagrangian methods in heat-flow problems and transport phenomena were introduced by the writer in some previous work. The present paper develops further one particular aspect of the method,-i.e., the elimination of “ignorable coordinates.” This is accomplished by a special choice of generalized coordinates, each of which is constituted by an arbitrary temperature distribution and an “associated flow field.” The latter is a vector field which is derived from the corresponding scalar field by a variational method. The procedure is valid for a certain class of nonlinear problems, provided we replace the temperature by the heat content as the unknown. It is shown that for normal coordinates derivation of the associated flow field is immediate. The use of normal coordinates and their associated flow fields is illustrated by an example. Introduction of Dirac functions and associated flow fields yields a procedure which constitutes a generalization of the classical formulation by Green’s functions and integral equations. This is illustrated by application to onedimensional problems of heating of a homogeneous or composite slab and directly verified by classical methods in the Appendix. N A PREVIOUS PUBLICATION~~~ haveintroducednew methods in heat-flow analysis. These methods have a two-fold basis; first, a new formulation of the thermodynamics of irreversible processes, and, second, the application of Lagrangian techniques to the mathematical analysis itself. The earlier developments were carried out in references 2, 3, and 4. We have recently reviewed in more detail in reference 5 the basic thermodynamic concepts and principles. The formulation of dissipative phenomena into a variational language can be achieved in many ways.$ The particular method which we have chosen is different from the classical variational approaches. It appears to be the most general and fits into a unified thermodynamic theory embracing a large category of physical phenomena, which leads to equations of the same type as in Lagrangian mechanics. A particularly useful concept which has been introduced is the generalized thermodynamic force by a @inciple of virtual work. In the case of thermal problems this results in a representation of the physical system by means of a vectorial flow field and to the use of a generalized thermal force to represent the externally applied tem

Mit Hilfe einer elektrischen Waage wird in einem Silber-Atomstrahl Dichte, mittlere Molekulargeschwindigkeit und deren Temperaturabhangigkeit mit einer Genauigkeit von ± 3% gemessen.

Die Arbeit gibt einen kurzen Bericht uber die Entstehung und die optischen Eigenschaften der Farbzentren, sowie ihre Rolle bei der Untersuchung des photochemischen Elementarprozesses in Salzkristallen.

A general survey is made of the field of mass spectrometry with special emphasis on those aspects considered important (a) because of extensive literature references and/or (b) by prospect for future development. These aspects include instrumentation, correlation studies, data storage, automation, and special types of spectra.