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Showing papers by "Cornell University published in 1979"


Journal ArticleDOI
N. D. Mermin1
TL;DR: Aspects of the theory of homotopy groups are described in a mathematical style closer to that of condensed matter physics than that of topology in this paper, where the focus is on mathematical pedagogy rather than on a systematic review of applications.
Abstract: Aspects of the theory of homotopy groups are described in a mathematical style closer to that of condensed matter physics than that of topology. The aim is to make more readily accessible to physicists the recent applications of homotopy theory to the study of defects in ordered media. Although many physical examples are woven into the development of the subject, the focus is on mathematical pedagogy rather than on a systematic review of applications.

1,612 citations


Journal ArticleDOI
01 Oct 1979-Icarus
TL;DR: In this paper, an expression for the effects of radiation pressure and Poynting-Robertson drag on small, spherical particles using the energy and momentum transformation laws of special relativity is derived.

1,419 citations



Journal ArticleDOI
TL;DR: Soy protein ingredients must possess appropriate functional properties for food applications and consumer acceptability as discussed by the authors, these properties reflect the composition and conformation of the proteins, their interactions with other food components, and they are affected by processing treatments and the environment.
Abstract: Soy protein ingredients must possess appropriate functional properties for food applications and consumer acceptability. these are the intrinsic physicochemical characteristics which affect the behavior of protein in food systems during processing, manufacturing, storage and preparation, e.g., sorption, solubility, gelation, surfactancy, ligand-binding, and film formation. These properties reflect the composition and conformation of the proteins, their interactions with other food components, and they are affected by processing treatments and the environment. Because functional properties are influenced by the composition, structure and conformation of ingredient proteins, systematic elucidation of the physical properties of component protein is expedient for understanding the mechanism of particular functional traints. The composition and properties of the major components of soy proteins are summarized, and the functional properties of soy proteins of importance in current applications (e.g., hydration, gelation, emulsifying, foaming and flavorbinding characteristics) are briefly reviewed.

1,194 citations


Book ChapterDOI
TL;DR: In this article, it is shown that direct simulation is not an alternative for practical computation and that the various sophisticated closures suffer from essentially the same problems as the direct simulations and therefore, are limited to homogeneous situations.
Abstract: Publisher Summary This chapter discusses that in many situations of practical importance, “second-order modeling” technique makes possible computations that often agree with what data is available. Inevitably, the technique is also applied in many situations in which data does not exist, which must be regarded as a dangerous practice as the limitations of the technique are not known with any precision. It is primarily the possibility of practical computation that has been responsible for the great interest in this method. Even in its most stripped-down form, it results in general in the simultaneous solution of four partial differential equations in the domain of interest; more elaborate models in a three-dimensional situation might require the simultaneous solution of as many as 36 partial differential equations to obtain the mechanical field only. This is within the capabilities of present computers at a reasonable price, which cannot be said of any other technique. The chapter explores that direct simulation is not an alternative for practical computation. The various sophisticated closures suffer from essentially the same problems as the direct simulations and therefore, are limited to homogeneous situations. Thus, the second-order modeling is the only possibility for practical computation.

1,069 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of hydrodynamic interactions on the coarsening rate of a cloud of droplets combining through diffusive coalescence is examined in detail, and the competing LifshitzSlyozov or evaporation-condensation mechanism is dominant.
Abstract: The influence of hydrodynamic interactions on the coarsening rate r of a mist of droplets combining through diffusive coalescence is examined in detail. For a sufficiently rarified mist, the competing LifshitzSlyozov or evaporation-condensation mechanism is dominant, but the volume fraction of precipitate actually produced in most off-critical quench experiments probably favors direct coalescence, When the minority phase is continuous, as in a quench at the critical concentration, surface-tension eA'ects lead to a crossover from r -t'" to r -t, where t is the time.

948 citations


Journal ArticleDOI
A. P. Young1
TL;DR: In this paper, the dislocation theory of two-dimensional melting due to Kosterlitz and Thouless is investigated for the triangular lattice, paying special attention to angular forces between dislocation pairs, which are equal in magnitude to the radial forces.
Abstract: The dislocation theory of two-dimensional melting due to Kosterlitz and Thouless is investigated for the triangular lattice, paying special attention to angular forces between dislocation pairs, which are equal in magnitude to the radial forces. Generalizing the dislocation Hamiltonian to an arbitrary vector Coulomb gas with different radial and angular interactions we find ${K}_{R}^{i}(T)\ensuremath{-}{K}_{R}^{i}({T}_{c}^{\ensuremath{-}})\ensuremath{\sim}{t}^{\overline{\ensuremath{ u}}}$, where ${K}_{R}^{i}$ is a renormalized coupling which includes the screening effect of bound dislocation pairs, the superscript $i$ signifies either a radial, $r$, or angular, $\ensuremath{\theta}$ part and $t$ is the reduced temperature, $t=\frac{({T}_{c}\ensuremath{-}T)}{{T}_{c}}$. The exponent $\overline{\ensuremath{ u}}$ varies as the ratio $\frac{{K}_{R}^{\ensuremath{\theta}}({T}_{c}^{\ensuremath{-}})}{{K}_{R}^{r}({T}_{c}^{\ensuremath{-}})}$ is changed and is equal to 0.3696... for the physical value of ${K}^{\ensuremath{\theta}}={K}^{r}$. In this case the shear and bulk elastic constants have the same temperature dependence as the ${K}_{R}^{i}$. We find that ${K}_{R}^{r}$ has finite universal value at ${T}_{c}$ and ${K}_{R}^{i}=0$ for $Tg{T}_{c}$, corresponding to metallic behavior of the vector Coulomb gas.

921 citations


Journal ArticleDOI
TL;DR: In this article, the eigenvalues of the evolution equations appear as exponents in anomalous logarithm corrections to the nominal power law of form factors determined by dimensional counting.

892 citations


Journal ArticleDOI
TL;DR: Evidence is analyzed regarding the extent, pathways, and mechanisms of the renal accumulation, filtration, absorption, and metabolism of small proteins, a heterogenous group of substances which constitute a small but biologically important fraction of total circulating proteins.

805 citations


Journal ArticleDOI
TL;DR: A new method is proposed which differs from the Bartels-Stewart algorithm in that A is only reduced to Hessenberg form, and the resulting algorithm is between 30 and 70 percent faster depending upon the dimensions of the matrices A and B.
Abstract: One of the most effective methods for solving the matrix equation AX+XB=C is the Bartels-Stewart algorithm. Key to this technique is the orthogonal reduction of A and B to triangular form using the QR algorithm for eigenvalues. A new method is proposed which differs from the Bartels-Stewart algorithm in that A is only reduced to Hessenberg form. The resulting algorithm is between 30 and 70 percent faster depending upon the dimensions of the matrices A and B . The stability of the new method is demonstrated through a roundoff error analysis and supported by numerical tests. Finally, it is shown how the techniques described can be applied and generalized to other matrix equation problems.

795 citations


Book
01 Jan 1979
TL;DR: Pimentel and Pimentel as discussed by the authors discussed the impact of energy use on the environment and the potential of solar energy in agricultural systems, including fish and aquacultural production.
Abstract: Energy and society / David Pimentel and Marcia Pimentel -- Energy and power / David Pimentel and Marcia Pimentel -- Solar energy in natural and managed ecosystems / David Pimentel and Marcia Pimentel -- Ecological systems, natural resources, and food supplies / David Pimentel and Marcia Pimentel -- Manipulating ecosystems for agriculture / David Pimentel and Marcia Pimentel -- Hunter-gatherers and early agriculture / David Pimentel and Marcia Pimentel -- Early livestock systems and animal power / David Pimentel and Marcia Pimentel -- Energy use in livestock production / David Pimentel and Marcia Pimentel -- Energy use in fish and aquacultural production / David Pimentel, Roland E. Shanks, and Jason C. Rylander -- Energy use in grain and legume production/ David Pimentel and Marcia Pimentel -- Energy use in fruit, vegetable, and forage production / David Pimentel and Marcia Pimentel -- Competition for land : development, food and fuel / David Pimentel and Marcia Pimentel -- Water resources for crop and biomass production / David Pimentel and Marcia Pimentel -- Biological diversity and agricultural/forestry systems / D. Pimentel ...[et al.] -- Food processing, packaging, and preparation / David Pimentel and Marcia Pimentel -- Transport of agricultural supplies and food / David Pimentel and Marcia Pimentel -- Solar energy production systems / D. Pimentel ... [et al.] -- Biomass : food versus fuel / D. Pimentel ... [et al.] -- Ethanol fuels : energy, economics, and the environment / David Pimentel -- The impact of energy use on the environment / D. Pimentel ... [et al.] -- Summing up : options and solutions / David Pimentel and Marcia Pimentel.

Journal ArticleDOI
TL;DR: In this article, the phase diagram of lattice gauge theories coupled to fixed-length scalar (Higgs) fields is studied and it is shown that when the Higgs fields transform like the fundamental representation of the gauge group, the confining phases are smoothly connected, i.e., they are not separated by a phase boundary.
Abstract: We study the phase diagram of lattice gauge theories coupled to fixed-length scalar (Higgs) fields. We consider several gauge groups: ${Z}_{2}$, U(1), and $\mathrm{SU}(N)$. We find that when the Higgs fields transform like the fundamental representation of the gauge group the Higgs and confining phases are smoothly connected, i.e., they are not separated by a phase boundary. When the Higgs fields transform like some representation other than the fundamental, a phase boundary may exist. This is the case for $\mathrm{SU}(N)$ with all the Higgs fields in the adjoint representation and for U(1) with all the Higgs fields in the charge-$N(Ng1)$ representation. We present an argument due to Wegner that indicates the stability of the pure gauge transition. Another phase, free charge or Coulomb, is generally present. In this regime, the spectrum of the theory contains massless gauge bosons (for continuous groups) and finite-energy states that represent free charges.

Journal ArticleDOI
TL;DR: In this article, a modified Benedict-Webb-Rubin equation has been used to derive an equation of state for the Lennard-Jones fluid that is valid over a wide range of temperatures and densities.
Abstract: Molecular dynamics calculations of the pressure and configurational energy of a Lennard-Jones fluid are reported for 108 state conditions in the density range 0·35 ≦ ρ* ≦ 1·20 and temperature range 0·5 ≦ T* ≦ 6 (where ρ* = ρσ3, T* = kT/e). Particular attention is paid to the dense fluid region (ρ* ≧ 0·9), including state conditions in the subcooled liquid region. These new simulation results for P and U are combined with those of previous workers, together with low density values calculated from the virial series and values of the second virial coefficients themselves, to derive an equation of state for the Lennard-Jones fluid that is valid over a wide range of temperatures and densities. The equation of state used is a modified Benedict-Webb-Rubin equation having 33 constants. It fits the data well over the density range 0 ≦ ρ* ≦ 1·2 and for T* values ranging from 0·5 to 6·0 (the exact temperature range depending to some extent on the density considered). We also calculate for the same range of state con...

Journal ArticleDOI
01 Jun 1979-Science
TL;DR: The cameras aboard Voyager 1 have provided a closeup view of the Jupiter system, revealing heretofore unknown characteristics and phenomena associated with the planet's atmosphere and the surfaces of its five major satellites.
Abstract: The cameras aboard Voyager 1 have provided a closeup view of the Jupiter system, revealing heretofore unknown characteristics and phenomena associated with the planet's atmosphere and the surfaces of its five major satellites. On Jupiter itself, atmospheric motions-the interaction of cloud systems-display complex vorticity. On its dark side, lightning and auroras are observed. A ring was discovered surrounding Jupiter. The satellite surfaces display dramatic differences including extensive active volcanism on Io, complex tectonism on Ganymede and possibly Europa, and flattened remnants of enormous impact features on Callisto.

Journal ArticleDOI
TL;DR: A review of previously suggested methods for analysis of experimental data of non-isothermal crystallization kinetics based on the Johnson-Mehl-Avrami transformation rate equation is given in this paper.
Abstract: A brief review is given of previously suggested methods for analysis of experimental data of non-isothermal crystallization kinetics based on the Johnson-Mehl-Avrami transformation rate equation. Conditions for applicability are outlined and an estimate of error is made. A method of non-isothermal analysis is presented which facilitates rapid data evaluation over large temperature ranges and which justifies the previous applications in the literature of Kissinger's method to the analysis of crystallizations kinetics. An extension of these methods is made to the case of growth rates which obey a Vogel-Further temperature relation.

Journal ArticleDOI
TL;DR: In this article, the weak limit in C[0, 1] of the integrated process is investigated, and it is shown that it converges for all m≧1 to some process that depends essentially on m.
Abstract: Let {X(s), −∞0.

Journal ArticleDOI
P. Holmes1
TL;DR: In this paper, the authors studied the bifurcational behavior of a nonlinear oscillator with a qualitative viewpoint and showed that for a wide range of moderate f extremely complicated nonperiodic motions arise.
Abstract: We study the nonlinear oscillator ẍ + δẋ — βx + αx 3 = f cos (ω t ) (A) from a qualitative viewpoint, concentrating on the bifurcational behaviour occurring as f > 0 increases for α, β, δ, ω to fixed > 0. In particular, we study the global nature of attracting motions arising as a result of bifurcations. We find that, for small and for large f , the behaviour is much as expected and that the conventional Krylov-Bogoliubov averaging theorem yields acceptable results. However, for a wide range of moderate f extremely complicated non-periodic motions arise. Such motions are called strange attractors or chaotic oscillations and have been detected in previous studies of autonomous o.d.es of dimension > 3. In the present case they are intimately connected with homoclinic orbits arising as a result of global bifurcations. We use recent results of Mel’nikov and others to prove that such motions occur in (A) and we study their structure by means of the Poincare map associated with (A). Using analogue and digital computer simulations, we provide a fairly complete characterization of the strange attractor arising for moderate f . This ergodic motion arises naturally from the deterministic differential equation (A).

Journal ArticleDOI
TL;DR: In this paper, the authors presented experimental evidence for chaotic type non-periodic motions of a deterministic magnetoelastic oscillator, analogous to solutions in non-linear dynamic systems possessing what have been called "strange attractors".

Journal ArticleDOI
TL;DR: In this paper, it is shown to within the accuracy of present-day computer-simulation studies that the bridge functions (i.e., the sum of elementary graphs, assumed zero in the hypernetted-chain approximation) constitute the same universal family of curves irrespective of the assumed pair potential.
Abstract: It is shown to within the accuracy of present-day computer-simulation studies that the bridge functions (i.e., the sum of elementary graphs, assumed zero in the hypernetted-chain approximation) constitute the same universal family of curves, irrespective of the assumed pair potential. In view of the known parametrized results for hard spheres, this observation introduces a new method in the theory of fluids, one that is applicable to any potential. The method requires the solution of a modified hypernetted-chain equation with inclusion of a one-parameter bridge-function family appropriate to hard spheres, and the single free parameter (the hard-sphere packing fraction) can be determined by appealing to the requirements of thermodynamic consistency. The assertion of universality is actually demonstrated via the application of this new method to a wide class of different potentials: e.g., hard spheres, Lennard-Jones, an inverse fifth power (${r}^{\ensuremath{-}5}$) applicable to the helium problem, the Coulomb potential (i.e., the one-component plasma), charged hard spheres, an oscillatory potential proposed for certain liquid metals, and the Yukawa potential.

Journal ArticleDOI
TL;DR: The authors found that bowlers often smile when socially engaged, looking at and talking to others, but not necessarily after scoring a spare or a strike at a bowling alley, while hockey fans rarely smiled while facing the pins but often smiled when facing their friends.
Abstract: Did smiling evolve as an expression of happiness, friendliness, or both? Naturalistic observation at a bowling alley (N — 1,793 balls) shows that bowlers often smile when socially engaged, looking at and talking to others, but not necessarily after scoring a spare or a strike. In a second study, bowlers (N =166 balls) rarely smiled while facing the pins but often smiled when facing their friends. At a hockey game, fans (N = 3,726 faces) smiled both when they were socially involved and after events favorable to their team. Pedestrians (TV = 663) were much more likely to smile when talking but only slightly more likely to smile in response to nice weather than to unpleasant weather. These four studies suggest a strong and robust association of smiling with a social motivation and an erratic association with emotional experience.

Journal ArticleDOI
20 Apr 1979-Science
TL;DR: Combined results from areas of silicate bedrock in the United States and Europe suggest that aluminum represents an important biogeochemical linkage between terrestrial and aquatic environments exposed to acid precipitation.
Abstract: Atmospheric inputs of sulfuric acid and nitric acid to noncalcareous higher-elevation watersheds in the White Mountain and Adirondack regions lead to comparatively high concentrations of dissolved aluminum in surface and ground waters. This phenomenon appears to result from modern increases in soil aluminum leaching. Transport of this aluminum to acidified lakes can lead to fish mortality. Combined results from areas of silicate bedrock in the United States and Europe suggest that aluminum represents an important biogeochemical linkage between terrestrial and aquatic environments exposed to acid precipitation.

Journal ArticleDOI
TL;DR: In this paper, the authors use the framework of network analysis to assess the social ecology of the parent and child in relation to its possible effects upon child development. But, they focus on the development of reciprocal exchange skills.
Abstract: COCHRAN, MONCRIEFF M., and BRASSARD, JANE ANTHONY. Child Development and Personal Social Networks. CmLD DEVELOPMENT, 1979, 50, 601-616. In this article we use the framework of network analysis to assess the social ecology of the parent and child in relation to its possible effects upon child development. The personal social network is defined, and several routes of network influence transmission articulated. Access to direct assistance, the provision of childrearing controls, and the availability of role models are postulated as major processes through which this influence is transmitted. In a section about the direct influences of networks on parent and child we discuss cognitive and social stimulation, direct support, observational model, and opportunities for participation. This section is followed by one devoted to the developing child, where we place particular emphasis on the formation of reciprocal exchange skills. We then shift to a consideration of possible child developmental outcomes, both cognitive and social. The final sections of the paper include discussions of the key elements making up the personal network as a social system and proposed directions for future research.

Journal ArticleDOI
TL;DR: A condensed monolayer of carbon on the surface of C-doped nickel single crystals has been observed at different bulk doping levels in the range of 10−1 to 1 at as discussed by the authors.

Journal ArticleDOI
23 Nov 1979-Science
TL;DR: Voyager 2, during its encounter with the Jupiter system, provided images that both complement and supplement in important ways the Voyager 1 images, which revealed a complex and, as yet, little-understood system of overlapping bright and dark linear features.
Abstract: Voyager 2, during its encounter with the Jupiter system, provided images that both complement and supplement in important ways the Voyager 1 images. While many changes have been observed in Jupiter's visual appearance, few, yet significant, changes have been detected in the principal atmospheric currents. Jupiter's ring system is strongly forward scattering at visual wavelengths and consists of a narrow annulus of highest particle density, within which is a broader region in which the density is lower. On Io, changes are observed in eruptive activity, plume structure, and surface albedo patterns. Europa's surface retains little or no record of intense meteorite bombardment, but does reveal a complex and, as yet, little-understood system of overlapping bright and dark linear features. Ganymede is found to have at least one unit of heavily cratered terrain on a surface that otherwise suggests widespread tectonism. Except for two large ringed basins, Callisto's entire surface is heavily cratered.

Journal ArticleDOI
TL;DR: In this paper, it was shown that the space of measured foliations with the quadratic forms on a fixed Riemann surface is homeomorphic to a sphere, and that the existence of projective classes of foliations is also homeomorphic.
Abstract: This paper concerns the interplay between the complex structure of a Riemann surface and the essentially Euclidean geometry induced by a quadratic differential. One aspect of this geometry is the " trajectory structure" of a quadratic differential which has long played a central role in Teichmfiller theory starting with Teichmiiller's proof of the existence and uniqueness of extremal maps. Ahlfors and Bers later gave proofs of that result. In other contexts, Jenkins and Strebel have studied quadratic differentials with closed trajectories. Starting from the dynamical problem of studying diffeomorphisms on a C ~ surface M, Thurston [17] invented measured ]ol~t io~. These are foliations with certain kinds of singularities and an invariantly defined transverse measure. A precise definition is given in Chapter I, w 1. This notion turns out to be the correct abstraction of the trajectory structure and metric induced by a quadratic differential. In this language our main statement says that given any measured ]oliation F on M and any complex structure X on M, there is a unique quadratic diHerential on the Riemann surface X whose horizontal trajectory structure realizes F. In particular any trajectory structure on one Riemann surface occurs uniquely on every Riemann surface of that genus. In the special case when the foliation has closed leaves, an analogous theorem was proved by Strebel [15]. Earlier Jenkins [13] had proved that quadratic differentials with closed trajectories existed as solutions of certain extremal problems. We deduce Strebel's theorem from ours in Chapter I, w 3. By identifying the space of measured foliations with the quadratic forms on a fixed Riemann surface, we are able to give an analytic and entirely different proof of a result of Thurston's [17]; that the space of projective classes of measured foliations is homeomorphic to a sphere. This is also done in Chapter I, w 3.

Journal ArticleDOI
TL;DR: In this paper, a model of a monolayer of atoms adsorbed on a crystalline surface is discussed, and the spectrum of small oscillations has two acoustic branches, one vanishing at the phase transition.
Abstract: A model of a monolayer of atoms adsorbed on a crystalline surface is discussed. When the initial incommensurability, $\ensuremath{\delta}$, between a reciprocal lattice vector of the monolayer and one of the substrate is small, the monolayer has a one-dimensional superstructure with period depending on $\ensuremath{\delta}$. For $\ensuremath{\delta}g{\ensuremath{\delta}}_{c}(T)$ the state is incommensurate; ${\ensuremath{\delta}}_{c}(T)$ decreases and vanishes at a ${T}_{c}$ given by the elastic moduli of the monolayer. The spectrum of small oscillations has two acoustic branches, one vanishing at the phase transition.

Journal ArticleDOI
J. van Buren1
TL;DR: In this article, the chemistry of the major primary cell wall components, pectins, hemicelluloses and cellulose, under conditions found during the normal handling of fruits and vegetables is discussed.
Abstract: This review is concerned with the chemistry of the major primary cell wall components, pectins, hemicelluloses and cellulose, under conditions found during the normal handling of fruits and vegetables. These polymeric components are considered separately, then their combined changes during maturation, storage and processing are covered. The effects of tissue conditions, pH, enzymes and salt concentrations on the rate and degree of change are discussed. A large part of the review deals with the important texture-affecting reactions of pectic materials including glycosidic hydrolysis, β-elimination type depolymerization, demethoxylation, and complex formation.



Journal ArticleDOI
11 Jan 1979-Nature
TL;DR: In this article, it is suggested that tholins occur in the interstellar medium and are responsible for some of the properties of the interstellar grains and gas, and additional occurrences of tholin are considered.
Abstract: The paper discusses tholins, defined as complex organic solids formed by the interaction of energy - for example, UV light or spark discharge - with various mixtures of cosmically abundant gases - CH4, C2H6, NH3, H2O, HCHO, and H2S. It is suggested that tholins occur in the interstellar medium and are responsible for some of the properties of the interstellar grains and gas. Additional occurrences of tholins are considered. Tholins have been produced experimentally; 50 or so pyrolytic fragments of the brown, sometimes sticky substances have been identified by gas chromatography-mass spectrometry, and the incidence of these fragments in tholins produced by different procedures is reported.