Scalar Source Research Articles

A lagrangian analysis of scalar transfer in vegetation canopies

AbstractTo study the dispersion of scalar trace constituents such as heat, water vapour or CO2 from extensive sources within vegetation canopies, a Lagrangian approach is essential because of the need to account for the influence of travel time (as a fraction of the Lagrangian time scale) on the dispersion properties of marked fluid particles. A simple, analytic Lagrangian theory is developed for a canopy in which the turbulence is homogeneous. For a given scalar source distribution, predictions are obtained for mean scalar concentration, vertical flux, terms in the balance equation for vertical flux, and vertical diffusivities at first, second and third order. the predictions agree remarkably well with measurements of dispersion from an elevated plane source within a model plant canopy in a wind tunnel. the theory also explains the countergradient heat and CO2 fluxes observed in real forest canopies.

A Lagrangian analysis of scalar transfer in vegetation canopies

To study the dispersion of scalar trace constituents such as heat, water vapour or CO2 from extensive sources within vegetation canopies, a Lagrangian approach is essential because of the need to account for the influence of travel time (as a fraction of the Lagrangian time scale) on the dispersion properties of marked fluid particles. A simple, analytic Lagrangian theory is developed for a canopy in which the turbulence is homogeneous. For a given scalar source distribution, predictions are obtained for mean scalar concentration, vertical flux, terms in the balance equation for vertical flux, and vertical diffusivities at first, second and third order. the predictions agree remarkably well with measurements of dispersion from an elevated plane source within a model plant canopy in a wind tunnel. the theory also explains the countergradient heat and CO2 fluxes observed in real forest canopies.

Three-dimensional classical spacetimes

The authors extend what is known about the structure of (2+1)-dimensional gravitational field theories. The non-existence of any Newtonian limit to these theories is investigated in the presence of Brans-Dicke scalar fields and non-linear curvature terms in the gravitational action. A number of new exact static and non-static solutions of (2+1) general relativity with scalar field, perfect fluid and magnetic field sources are presented and studied in detail. Some of these possess a correspondence with (3+1) solutions of general relativity through a Kaluza-Klein type reduction and exhibit the 'wedge' structure of (3+1)-dimensional solutions describing line sources like vacuum strings. An algebraic classification of (2+1) gravitational fields is derived using the Bach-Weyl tensor. The description of the general cosmological solution is given in terms of arbitrary spatial functions independently specified on a spacelike surface of constant time together with a series approximation to spacetime in the vicinity of a general cosmological singularity.

A very broad band analysis of the Michoacan, Mexico, Earthquake of September 19, 1985

Long‐period seismograms from the GDSN, RSTN, and IDA network are used in a centroid‐moment tensor analysis of the September 19, 1985 Michoacan, Mexico, earthquake (Ms=8.1). The long‐period data are also used together with broad band displacement P‐waveforms in a joint very broad band inversion for the moment tensor and the moment rate distribution in time and space. Results are that the earthquake had a total scalar moment of 1.1×1028 dyne‐cm and that the moment release occurred mainly in two subevents, the second of which was located approximately 70 km southeast of the first. Observations of Earth's normal modes at ultra long periods (600 to 2000 sec) are shown to be consistent with the obtained scalar moment and source mechanism.

Supersymmetry — lost or found?

We present a comprehensive analysis of missing transverse-energy events at the CERN p p collider which would arise from a supersymmetric theory. This analysis takes into account, the new 1984 UA1 cuts, triggers and resolutions. Our conclusions from the newly reported 1984 data are that any excess number of monojet events is highly unlikely to come from gluino or scalar quark production. The new data lead to the very restrictive limits: M( g ̃ ) and M( q ̃ ) > 60−70 GeV . The two intriguing dijet events with E T(missing) > 55 GeV are not inconsistent with an 80 GeV gluino or scalar quark source. The above conclusions have been obtained assuming that photinos are lighter than gluinos and live long enough to escape collider detectors. An alternative picture where the higgsino is the lightest supersymmetric particle is briefly discussed.

Five-dimensional cosmological models with massless scalar fields

Simple cosmologies are constructed from solutions of the five-dimensional Einstein equations with a real massless non-self-interacting scalar field source. It is demonstrated that non-trivial cosmological models occur only if the metric of the homogeneous and isotropic three-space of the universe has non-positive constant curvature. For the case of flat three-space, it is further demonstrated that two classes of solutions result - one of which has a power-law type of expansion for three-space and contraction of the one-dimensional internal space, while the other class has an exponential expansion for three-space and exponential contraction of the internal space. The exponentially expanding solutions are the limiting case of the power-law expanding solutions. Hence, our model is consistent with a simple inflationary scenario.

A body-wave analysis of the 1966 Gisborne, New Zealand, earthquake

The M l = 6.2 Gisborne earthquake of March 4, 1966 occurred along the East Coast of the North Island, New Zealand. Modeling of P and S body waves shows that the focal mechanism of this event is consistent with northwestward thrusting of the Pacific Plate beneath the North Island ( ϑ = 249°, δ = 25° and λ = 131°). The focal depth is constrained to 18 km, significantly less than the values of 25–30 km computed from local network data. Estimates of the scalar moment, source duration and stress-drop for the event are 4 × 10 24 dyne-cm, 2–3 s, and 20–120 bar, respectively. Cross-correlation errors of synthetic to observed waveforms were computed for all possible P and T axis locations and slip vector orientations and contoured on a projection of the focal sphere. The error contour at which the synthetic waveforms distinctly diverged from the observed waveforms was established by eye. The procedure shows that the analysis of long-period body waves, at least in this case, provides much better constraint on focal mechanism orientation than does first motion data alone.

Finiteness of gravitational corrections to magnetic moments and supergravity embedding

We calculate the one-loop O( κ 2) contribution to the anomalous magnetic moment of a lepton in the framework of N = 1 supergravity coupled to super-QED with a charged massive scalar multiplet source, using both supersymmetry violating and preserving regularizations. Since a Pauli term is forbidden by supersymmetry, the ordinary gravity plus QED contribution must be just the negative of that given by the new supersymmetry diagrams in the latter scheme. In particular, the infinite part of the new terms' contribution vanishes; the reason for this is traced to an effective chiral-dual symmetry of our sector. Thus, the “miracle” of the moment's finiteness in ordinary gravity is accounted by supergravity embedding. The significance and implications of regularization ambiguities are also discussed.

Transverse vertices in electrodynamics and the gauge technique

The inclusion of transverse vertex corrections in the gauge technique, needed for the restoration of gauge covariance, results in a self-consistent equation for the source propagator spectral function which agrees with perturbation theory when expanded to order e4. The authors have managed to solve the equation in the infrared and ultraviolet limits, for scalar and spinor sources, in an arbitrary covariant gauge. The gauge covariance at asymptopia is thus established.

Three-dimensional magnetostatic fields from point-matched integral equations with linearly varying scalar sources

Analytic formulas are given for the shape factors necessary to compute the scalar magnetic potential from single and double layers and the magnetic fields from the single layers using integral equations with linear varying sources. The formulas apply to triangular elements of the polyhedral body comprising the problem geometry. Several problems have been analyzed; the computed results compare favorably with existing approximate theory, experimental data, and other integral equation formulations.

Functional integral and anomalies in theories withS,P,V, andAcurrents

We investigate anomalous divergences in a theory of fermions coupled in an $\mathrm{SU}(N)$-invariant way to scalar, pseudoscalar, vector, and axial-vector sources using a path-integral formulation of the theory. All of the naive anomalous divergences for normal- and abnormal-parity $n$-point functions which were previously obtained in Pauli-Villars-regulated perturbation theory are reproduced. A mnemonic for characterizing all the possible anomalies in the path-integral scheme we use is described. We eliminate all of the normal-parity anomalies without introducing Lagrangian counterterms.

Scalar timing in memory.

A recent report of ours’ proposed an information-processing account of temporal generalization. The account posited a clock process, which was the basic time measurement device, and working and reference memory for storing the output of the clock either temporarily or relatively permanently. Records of time intervals in working and reference memory were then compared using a binary decision process, which dictated responding or not responding. The analysis concentrated on a relativistic Weber’s law property of the data from temporal generalization, and the constraints this property imposed on sources of variance in the information-processing stages. Our purpose here is to summarize that work and generalize the model in two ways: First we consider several sources of variance operating simultaneously. The original analysis demonstrated that if only one source of variance is present, it must be a scalar source, that is, it must result in a variable memory for which variance increases with the square of the mean.’ In the generalized account proposed here, we will develop the conclusion that scalar sources dominate in some time ranges, while other sources may dominate in others. These ideas are then applied to two additional timing tasks with different characteristics.

Local symmetries of the Einstein-Yang-Mills theory as phase-space transformations

For Einstein's theory of gravitation coupled to scalar and Yang-Mills sources we implement local symmetries as canonical transformations in a phase space. This is carried out without any action principle. The procedure allows one to rederive the supermomentum for the Einstein-scalar fields, and both the supermomentum and super-Hamiltonian of the coupled Einstein-Yang-Mills system. For the latter theory it turns out that general coordinate transformations alone cannot be realized in a phase space.

Correlation Theory of Wavefields Generated by Fluctuating, Three-dimensional, Scalar Sources

The general results derived in part I of this investigation are applied to study the radiant intensity and the degree of spatial coherence of the far field generated by certain types of fluctuating three-dimensional scalar sources. One class of sources that are considered are the three-dimensional analogues of quasihomogeneous sources, which provide a good representation for many natural sources of light. Three-dimensional analogues of the so-called Schell-model sources are also considered, under the assumptions that both the spatial distribution of the intensity and of the degree of spatial coherence of the source have the form of gaussian distributions. Several general theorems relating to fields generated by sources of both kinds are derived and the main results are illustrated by curves. Various limiting forms of the solutions are also considered.

Correlation Theory of Wavefields Generated by Fluctuating, Three-dimensional, Primary, Scalar Sources

Correlation Theory of Wavefields Generated by Fluctuating, Three-dimensional, Primary, Scalar Sources

High-frequency electromagnetic fields on perfectly conducting concave cylindrical surfaces

High-frequency fields are investigated on the surface of a perfectly conducting concave circular cylindrical segment excited by an arbitrarily oriented dipole located on the surface. The vector fields are derived from two scalar Green's functions which are constructed as contour integrals and evaluated asymptotically in two alternative ways. In one representation an appropriate number of geometrical optics rays is extracted to provide canonical remainder integrals with highly improved convergence characteristics. In the second approach a properly determined combination of rays together with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</tex> - and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</tex> -type whispering gallery modes is utilized. Numerical results are presented for the magnitude and polarization of the fields as functions of dipole orientation and observation point location, and are interpreted in terms of the physical models implied by the various field representations. As for scalar sources, the hybrid ray-mode formulation of vector-source excited fields provides a physically attractive and numerically efficient scheme.

Impulse response function for a scalar wave source in a compliant baffle

The velocity potential impulse response function is computed for a cylindrical piston in a compliant baffle. It is shown that, in general, the impulse response is that of a piston in a noncompliant baffle, plus a small wake, or reverberation, which dies out in a time the order of the transit time of the wave to the point in space. The slow decay of the wake means that the energy in the wake from a short pulse will be considerable fraction of the total energy. The solution is obtained in closed from from a baffle which matches the fluid impedance. Second sound heat pulse propagation in helium II obeys the scalar wave equation and it will have a second sound heat pulse impulse response which is isomorphous with that of the pressure wave in a fluid. It is pointed out that the analyses of the transient electromagnetic field of a vertical dipole antenna above a conducting earth, and the seismic transients in a layered earth can be of use in discussing the acoustic problem explored here.

Solving the gauge identities

The author shows how one may 'solve' the Ward-Takahashi identities of a gauge theory to determine the longitudinal Green functions in terms of the basic source propagators and in such a way that on-shell amplitudes reduce to their classical values. The method is demonstrated for scalar, spinor and vector sources in Lorentz covariant and non-covariant Abelian gauges; but for non-Abelian groups he works in the axial gauge in order to avoid fictitious terms which otherwise spoil the procedure.

On the question of the existence of nonradiating primary planar sources of finite extent

It is known that certain oscillating three-dimensional charge-current distributions do not radiate. In this paper we show that no monochromatic, well-behaved, two-dimensional scalar source distribution that is localized within a finite area may be nonradiating. We also generalize this result to fluctuating, stationary planar source distributions of any arbitrary state of coherence.

On solutions of Einstein's equations with scalar zero-mass source

It is shown that most, if not all, previously known solutions of the gravitational field equations with a zero-mass scalar sourceo can be found “without solving the field equations” by applying known theorems. Penney's recent solution, characterized in part by having a conformally flat metricds2=e2σηijdxidxj is shown to be insufficiently general when his vectorai is null. The problem is reformulated and new solutions of the conformally flat type are found. These are, in general, such that o and σ are no longer linearly related.