Showing papers by "Naval Postgraduate School published in 1977"
TL;DR: In this article, the linear, lumped-constant, behaviour of single bubbles is reviewed and formulated in terms of the physical constants of the medium liquid, the bubble gas and the interface between.
291 citations
TL;DR: In this article, an entrainment hypothesis dependent upon the relative distribution of turbulent energy between horizontal and vertical components is offered as a plausible mechanism for governing both entrainments and layer retreat.
Abstract: A new one-dimensional bulk model of the mixed layer of the upper ocean is presented. An entrainment hypothesis dependent upon the relative distribution of turbulent energy between horizontal and vertical components is offered as a plausible mechanism for governing both entrainment and layer retreat. This model has two properties not previously demonstrated: (i) The fraction of wind-generated turbulent kinetic energy partitioned to potential energy increase by means of mixed layer deepening is dependent upon layer stability, H*=h/L, as measured by the ratio of mixed layer depth h to Obukhov length L. This results in a modulation of the mean entrainment rate by the diurnal heating and cooling cycle. (ii) Viscous dissipation is enhanced for increased values of Ro−1= hf/u*, where f is the Coriolis parameter and u*. the friction velocity for the water. This enables a cyclical steady state to occur over an annual period by limiting maximum layer depth. A nondimensional framework used to present the gen...
147 citations
122 citations
TL;DR: In this article, it was shown that simple linear damping, justified by budget studies which revealed the important role of cumulus momentum transport, has a strong influence at low frequencies on the forced equatorial waves and results in two types of dispersive relationships.
Abstract: In this paper we deal with the interpretation of observed oscillations in the tropical troposphere and stratosphere within the framework of the equatorial wave theory. A difficulty with this problem arises when one compares the short vertical wavelength (or equivalent depth) predicted by the classical theory and the observed large vertical scales associated with the low Doppler-shifted frequencies of the tropospheric oscillations. In this analysis it is shown that the inclusion of simple linear damping, justified by budget studies which revealed the important role of cumulus momentum transport, has a strong influence at low frequencies on the forced equatorial waves and results in two types of dispersive relationships. The first type is characteristic of the regular internal gravity waves which have fast phase speeds and weak vertical attenuation. The second type is dominated by the viscous damping time scale and has slow phase speeds and strong vertical trapping. The theory predicts that the str...
120 citations
73 citations
TL;DR: In this article, a computer model was developed for the solid-fuel ramjet combustor, which appears to be a good qualitative tool for examining the effects of combustor geometry and test environment on fuel regression rate, flame pattern, and combustion efficiency.
Abstract: A computer model was developed for the solid-fuel ramjet combustor. The model appears to be a good qualitative tool for examining the effects of combustor geometry and test environment on fuel regression rate, flame pattern, and combustion efficiency. Additional model verification is required.
69 citations
TL;DR: In this article, the authors examined the relationship between perceived environmental uncertainty and the information search behavior of managers in organizational boundary-spanning positions, and found that certain information search behaviors appear to be associated with perceived uncertainty.
Abstract: This study empirically examines the relationship between perceived environmental uncertainty and the information search behavior of managers in organizational boundary-spanning positions. It tests hypotheses related to the perceived importance managers attach to external, internal, formal, and informal information sources, as environmental uncertainty increases. Managerial search behavior of electronics firms is contrasted with that in wood products firms. The findings suggest that certain information search behaviors appear to be associated with perceived uncertainty. Significant positive correlations were found to exist between the level of uncertainty perceived by managers and (1) their reliance on external sources of information, (2) their use of informal sources of information, (3) their frequency of use of all information sources, and (4) the amount of time they allocate to information gathering activities.
48 citations
TL;DR: In this article, a class of methods for local interpolation at irregularly spaced points for functions of two or more variables is developed, based on a weighted average of the values of local interpolating functions.
Abstract: : A class of methods for local interpolation at irregularly spaced points for functions of two or more variables is developed. The methods are based on a weighted average of the values of local interpolating functions, with the local interpolating functions and the weighting functions chosen so as to incorporate the desired smoothness. Numerical results for several interpolation functions from this class are compared with global approximations, some of which are local when implemented on a computer.
45 citations
TL;DR: In this paper, the performance of coherent anti-stokes Raman spectroscopy (CARS) relative to incoherent Raman scattering (RSS) for gases is compared for four gases: hydrogen, nitrogen, oxygen, and carbon monoxide.
Abstract: The performance capabilities of coherent anti-stokes Raman spectroscopy (CARS) relative to incoherent Raman scattering and absorption spectroscopy are considered for gases. Four gases are considered for model calculations: hydrogen, nitrogen, oxygen, and carbon monoxide. The signal/noise ratio is estimated for these molecules under a number of assumed experimental conditions. The signal/noise ratios for CARS and Raman scattering scale quite differently with partial pressure and temperature. CARS offers distinct advantages when detecting a major component of a gas mixture at total pressures of considerably less than 1 atm pressure. Raman scattering offers 1 to 2 orders of magnitude greater sensitivity for a signal/noise ratio of unity when detecting a minor component of a gaseous mixture at 1 atm total pressure. These model calculations should be of use when a specific experimental method is to be chosen for spectroscopic examination.
43 citations
TL;DR: In this article, the saturation range in the frequency spectrum of wind-generated waves is derived using linear wave theory as a spectral transfer function and the horizontal velocity spectrum Su(ω) ∝ ω−3.
Abstract: The saturation range in the frequency spectrum of wind-generated waves is rederived. Laboratory and theoretical work show that wave breaking is the result of kinematic instability, suggesting that wave celerity is the governing parameter in the saturation range. Using similarity arguments, a general formulation is rederived giving the wave profile spectrum Sη(ω) ∝ ω−5 in deep water as derived by Phillips and Sη(ω) ∝ ω−3 in shallow water. The velocity spectrum in the saturation range is derived using linear wave theory as a spectral transfer function. In both deep and shallow water the horizontal velocity spectrum Su(ω) ∝ ω−3. Wave and velocity measurements made in deep and shallow water are presented showing agreement with theory.
41 citations
01 Jan 1977
TL;DR: In this article, the mean and variance of a linear function with arbitrary multivanate randomness in its components are estimated using Tchebycheff-type probability statements, which can be used to accomodate and exploit stochastic dependence.
Abstract: Applications in operations research often employ models which contain linear functions. These linear functions may have some components coefficients and variables which are random. For instance, linear functions in mathematical programming often represent models of processes which exhibit randomness in resource availability, consumption rates, and activity levels. Even when the linearity assumptions of these models is unquestioned, the effects of the randomness in the functions is of concern. Methods to accomodate, or at least estimate for a linear function the implications of randomness in its components typically make several simplifying assumptions. Unfortunately, when components are known to be random in a general, multivariate dependent fashion, concise specification of the randomness exhibited by the linear function is, at best, extremely complicated, usually requiring severe, unrealistic restrictions on the density functions of the random components. Frequent stipulations include assertion of normality of independence-yet, observed data, accepted collateral theory and common sense may dictate that a symmetric distribution with infinite domain limits is inappropriate, or that a dependent structure is definitely present. For example, random resource levels may be highly correlated due to economic conditions, and non-negative for physical reasons. Often, an investigation is performed by discretizing the random components at point quantile levels, or by replacing the random components by their means-methods which give a deterministic “equivalent” model with constant terms, but possibly very misleading results. Outright simulation can be used, but requires considerable time investment for setup and debugging especially for generation of dependent sequences of pseudorandom variates and gives results with high parametric specificity and computation cost. This paper shows how to use elementary methods to estimate the mean and variance of a linear function with arbitrary multivanate randomness in its components. Expressions are given for the mean and variance and are used to make Tchebycheff-type probability statements which can accomodate and exploit stochastic dependence. Simple estimation examples are given which lead to illustrative applications with dependent-stochastic programming models.
01 Jun 1977
TL;DR: A relatively straightforward, nearly algorithmic procedure for deriving model-based pilot-centered display requirements is presented, and some novel applications of the optimal pilot model are discussed, including the generation of vehicle-handling-qualities levels via numerical pilot-opinion ratings.
Abstract: A relatively straightforward, nearly algorithmic procedure for deriving model-based pilot-centered display requirements is presented. A pilot model based on modern control theory serves as the backbone of the design methodology, which is specifically directed toward the synthesis of head-down, electronic cockpit display formats. Some novel applications of the optimal pilot model are discussed, including the generation of vehicle-handling-qualities levels via numerical pilot-opinion ratings. An analytical design example is offered which aids in the definition of a format for the electronic display to be used in a UH-1H helicopter in a landing-approach task involving longitudinal and lateral degrees of freedom. It is proposed that the design procedure offers a systematic means for generating candidate display formats and flight-director laws for simulator evaluation.
TL;DR: In this article, the performance of various materials used in contemporary lead-acid storage batteries are reviewed and their relevance to service behavior is emphasized. And the interrelationships between the various component materials of leadacid systems, including grid alloys, active material compounds, polymeric separators, and conductors and containers, are considered.
TL;DR: In this article, the morphology of anodic deposits on zinc was studied by scanning electron microscopy and potentiostatic techniques, and the anodic film structure for zinc-steel couples in sea water is a porous three-dimensional network of discrete single crystal plates of ZnO.
TL;DR: In this paper, the problem of formulating lumpability hypotheses when the transition probability matrix P is not known and is possibly of large dimension is discussed, and an approximate test of these hypotheses is described, based on well-known nonparametric methods.
Abstract: Under certain conditions the state space of a discrete parameter Markov chain may be partitioned to form a smaller lumped chain that retains the Markov property. The problem of formulating lump-ability hypotheses when the transition probability matrix P is not known and is possibly of large dimension is discussed. An approximate test of these hypotheses is described, based on well-known nonparametric methods. The procedure is illustrated with an application to a Markov manpower model.
TL;DR: In this paper, an analysis of the tidal forces present during occurrence of the major earthquakes recorded in periods of several years duration is presented for two regions along the San Andreas fault in central California, and the evidence provided by these analyses does not support the hypothesis that tidal-force levels or rates of change have significant effects on earthquake occurrences in the regions considered.
Abstract: Analyses of tidal forces present during occurrence of the major earthquakes recorded in periods of several years duration are presented for two regions along the San Andreas fault in central California. Components of tidal force and their time rates of change are computed for each earthquake in the sample. The distributions of these force and jerk quantities for actual earthquakes are compared with corresponding distributions obtained for pseudo-earthquakes generated under the hypothesis of random occurrence. It is concluded that the evidence provided by these analyses does not support the hypothesis that tidal-force levels or rates of change have significant effects on earthquake occurrences in the regions considered.
TL;DR: In this paper, a mathematical theory for predicting force annihilation from initial conditions without explicitly computing force-level trajectories for deterministic Lanchester-type attrition equations for combat between two homogeneous forces with temporal variations in fire effectivenesses (as expressed by the Lanchester attrition-rate coefficients).
Abstract: This paper develops a mathematical theory for predicting force annihilation from initial conditions without explicitly computing force-level trajectories for deterministic Lanchester-type “square-law” attrition equations for combat between two homogeneous forces with temporal variations in fire effectivenesses (as expressed by the Lanchester attrition-rate coefficients). It introduces a canonical auxiliary parity-condition problem for the determination of a single parity-condition parameter (“the enemy force equivalent of a friendly force of unit strength”) and new exponential-like general Lanchester functions. Prediction of force annihilation within a fixed finite time would involve the use of tabulations of the quotient of two Lanchester functions. These force-annihilation results provide further information on the mathematical properties of hyperbolic-like general Lanchester functions: in particular, the parity-condition parameter is related to the range of the quotient of two such hyperbolic-like general Lanchester functions. Different parity-condition parameter results and different new exponential-like general Lanchester functions arise from different mathematical forms for the attrition-rate coefficients. This theory is applied to general power attrition-rate coefficients: exact force-annihilation results are obtained when the so-called offset parameter is equal to zero; while upper and lower bounds for the parity-condition parameter are obtained when the offset parameter is positive.
TL;DR: In this article, the geometric slip distance lambda/sub G/ is incorporated into the model for elevated temperature deformation and the mechanical behavior of these particulate composites is then consistently and accurately described for temperatures from 0.1 to 0.8 T/sub M/.
TL;DR: In this article, the authors investigated the energy dependence of photoabsorption experiments in the spherical nucleus 141 Pr, the quasispherical dynamically deformed 197 Au, and the statically deformed 165 Ho, and found that the function which describes best the reduced transition probability is given by the Breit-Wigner form rather than the Lorentz form.
TL;DR: In this paper, an unsteady linearized formulation based on Oswatitsch-Keune's parabolic method is developed to analyze transonic flow past oscillating slender bodies, and all solutions can be derived by a simpler method directly in the physical plane.
Abstract: An unsteady linearized formulation based on Oswatitsch-Keune's parabolic method is developed to analyze transonic flow past oscillating slender bodies. In contrast to the widely used integral transform method, it is shown that all solutions can be derived by a simpler method directly in the physical plane. By various expansion procedures, low-frequency solutions then are derived according to two clearly defined frequency ranges. Adams-Sears' iteration is employed to account for the second-order effects. Stability derivatives are compared with available theories and data. It is found that the derivatives depend more sensitively on thickness than on the reduced frequency. Finally, a critical assessment of the present method is given.
TL;DR: In this paper, a nonparametric test of the hypothesis of no treatment effect is suggested for a situation where measures of the severity of the condition treated can be obtained and ranked both pre- and post-treatment.
Abstract: A nonparametric test of the hypothesis of no treatment effect is suggested for a situation where measures of the severity of the condition treated can be obtained and ranked both pre- and post-treatment. The test allows use to be made of the pre-treatment rank as a "concomitant variable," and is based on the nature and degree of permutation of the post-treatment ranks relative to the pre-treatment ranks. Evidence is given which shows that the distribution of the suggested test statistic rapidly approaches the F distribution as the number of subjects is increased. For small samples, a randomization test may be performed.
TL;DR: In this article, the authors investigated the possible roles played by the temporal and spatial sea surface temperature (SST) variations on the tropical easterly waves and found that the warmer SST represents stronger thermal control through cumulus heating.
Abstract: The structure and properties of tropical easterly waves have been found to vary considerably between different regimes and time periods. This study investigates the possible roles played by the temporal and spatial sea surface temperature (SST) variations on the waves. Time series of tropical western Pacific radiosonde data during two contrasting 8-month periods of SST anomalies, May–December 1972, which had abnormally high SST in the central and eastern Pacific, and May-December 1973 which had below normal SST in the same region, are analyzed. In both periods, the waves have the same periodicity of 4–5 days and a lower tropospheric zonal wavelength on the order of 3300 km, but their vertical phase and amplitude distributions as well as the thermal structures are different. The results are discussed in terms of two possible influences the SST variations may have on the waves: 1) a direct effect in which the warmer SST represents stronger thermal control through cumulus heating and 2) an indirect ...
01 Jan 1977
TL;DR: The concepts, framework and methodology of the technology transfer process are discussed, and a model of the transfer mechanism is developed that is useful in terms of exposing difficiencies in the acceptance of new and/or innovative technology.
Abstract: The concepts, framework and methodology of the technology transfer process are discussed. On the basis of research a model of the transfer mechanism is developed. This model is carried through several iterations to arrive at a predictive model of technology transfer. The model is useful in terms of exposing difficiencies in the acceptance of new and/or innovative technology. In addition the model has a future usefulness in terms of providing a basis for a quantitative measure of the effectiveness of an organization to capitalize on the technology transfer process.
TL;DR: In this article, the formation and deterioration of oxide films on several contemporary high-temperature alloys was studied in various carbonaceous gas atmospheres, and the effects of various preoxidation treatments were evaluated.
Abstract: Formation and deterioration of oxide films on several contemporary high-temperature alloys was studied in various carbonaceous gas atmospheres. Scanning electron microscopy and metallographic examination were applied to films on Fe-Cr-Ni and Ni-Cr-Al type alloy compositions exposed in CH4/H2 and CO/CO2 atmospheres at temperatures up to 900° C and pressures up to 900 psi (6.2 × 106 N/m2). The effects of various preoxidation treatments were evaluated. Reduction of certain oxide phases is observed to promote catalytic gas decomposition. Al2O3components in the films are observed to be stable under the reducing conditions experienced. Carbon uptake by various alloys is found to be quite sensitive to surface finish, with an observed increase in penetration with surface roughness.
01 Jan 1977
TL;DR: In this article, the authors compared two Fourier transform formulations of the propagation problem: the Fresnel integral and the spatial frequency domain approach, and the following features are compared: restrictions on maximum and minimum propagation distances, sample sizes and number of samples required, adaptability to image processing techniques and computational requirements.
Abstract: Computer-aided acoustical imaging systems and computer simulations of other acoustic imaging techniques frequently require simulation of linear acoustic diffraction of large complex-valued data arrays. Computation efficiency requires the use of fast Fourier transform techniques. This paper compares two Fourier transform formulations of the propagation problem: the Fresnel integral and the spatial frequency domain approach. The following features are compared: restrictions on maximum and minimum propagation distances, sample sizes and number of samples required, adaptability to image processing techniques, and computational requirements.
TL;DR: In this paper, the performance of particulate composites of cadmium containing 0.6 to 3 μm size particles of boron and tungsten (up to 30 vol %) were studied from −196 to 260° C (0.13 to 0.9Tm).
Abstract: Mechanical behaviour of particulate composites of cadmium containing 0.6 to 3 μm size particles of boron and tungsten (up to 30 vol %) were studied from −196 to 260° C (0.13 to 0.9Tm). The marked strengthening of cadmium by the presence of fine particles is attributed to significant grain size and texture strengthening effects as well as to dispersion hardening effects.
TL;DR: In this paper, a new approach to the stochastic analysis of general compartment models is presented based on the concept of diffusion approximations, where the state of a compartment system is represented as the superposition of a deterministic process and a random-noise process.
Abstract: A new approach to the stochastic analysis of general compartment models is presented. The analysis is based on the concept of diffusion approximations. The state of a compartment system is represented as the superposition of a deterministic process (characterized by a system of ordinary differential equations) and a random-noise process (characterized by stochastic differential equations). All transition-rate parameters are permitted to be time-dependent. Numerical solutions are presented for the two-compartment case and compared with those of Cardenas and Matis [10]. Extensions to nonlinear compartment models are discussed.