David W. Kraft - Academia.edu (original) (raw)
Papers by David W. Kraft
Nucleation and Atmospheric Aerosols, 2004
It is proposed that when the era of the big-bang nucleosynthesis ended, almost all of the 75 perc... more It is proposed that when the era of the big-bang nucleosynthesis ended, almost all of the 75 percent of the observed total baryonic matter remained in the form of hydrogen and continued to exist in the form of protons and electrons. They are present today as baryonic dark matter in the form of intergalactic hydrogen plasma. To test our hypothesis we have investigated the effects of Thomson scattering by free electrons on the reported dimming of Type Ia supernovae. The quantitative results of our calculation suggest that the dimming of these supernovae, which are dimmer than expected and hence more distant than predicted by Hubble expansion, is a result of Thomson scattering without cosmic acceleration.
Bulletin of the American Physical Society, Nov 7, 2015
Primary cosmic rays are nucleons from outer space incident upon the Earth’s atmosphere. Their flu... more Primary cosmic rays are nucleons from outer space incident upon the Earth’s atmosphere. Their flux varies with energy E as \u1d438^(−\u1d6fe) in which the exponent assumes values between 2.5 and 3.2. We provide herein a framework to account for these values. We consider the particles’ kinetic temperature T and introduce a damping factor \u1d447^(−\u1d45a) to account for non head-on collisions. It is the presence of the index m which can provide values of γ
Bulletin of the American Physical Society, 2016
We study the evolution of asteroid orbits in a restricted three-body problem formulation consisti... more We study the evolution of asteroid orbits in a restricted three-body problem formulation consisting of the Sun, the planet Jupiter and an unspecified asteroid of negligible mass. It was discovered by Kirkwood [l] that the distribution of asteroid orbits contains gaps for orbits whose period is commensurate with that of Jupiter. Detailed computations in threedimensional, many-body formulations found that test bodies initially placed in a forbidden orbit did not develop large eccentricities or leave the gap even after the passage of 10 5 years [2]. In the present two-dimensional simulation, an extension of earlier work [3], we perform numerical integrations of the coupled equations of motion for Jupiter and the asteroid. Under assumptions of a stationary Sun and a circular orbit for Jupiter, we find that test bodies initially placed in a forbidden orbit can develop a large eccentricity after relatively few orbits.
Fusion Science and Technology, 2012
Energy is released when light nuclei fuse to form heavier nuclei. This is the energy which powers... more Energy is released when light nuclei fuse to form heavier nuclei. This is the energy which powers stars such as the Sun. The amount of energy released is related to the difference in the masses of the initial and final nuclei according to E = mc 2. Nuclear forces are of short range. Hence reactions occur only when nuclei are in close proximity and to achieve this they must have energy sufficient to overcome their repulsive electrostatic forces. This requires such high temperatures as 15,000,000 K as in the Sun.
The Physics Teacher, 1995
EJ518772 - Geometric Derivation of Radial Acceleration Magnitude.
Proceedings of the 2014 Zone 1 Conference of the American Society for Engineering Education, 2014
Treatments of the exponential function in Calculus textbooks are often cursory in that they treat... more Treatments of the exponential function in Calculus textbooks are often cursory in that they treat unchecked (Malthusian) growth processes without examination of their consequences. Through the use of problems posed to students, we illustrate the implications of such processes when applied to growth of populations and to growth in the rates of consumption of nonrenewable resources.
Causality and Locality in Modern Physics, 1998
The universal constants G, c and ħ comprise the Planck mass, (ћ c/G) 1/2 ≈ 10−5 g. We present arg... more The universal constants G, c and ħ comprise the Planck mass, (ћ c/G) 1/2 ≈ 10−5 g. We present arguments for the existence and properties of particles with this mass, describe how they serve as the constituents for a gravitational theory of matter, and explore the cosmological implications of this theory. Specifically, we describe a gravitational rotator model for baryons and show how this accounts for baryon stability and the three-quark saturation of baryons and that it predicts the Gell-Mann-Okubo mass formula for the SU 3 octet and the equal spacing rule for the SU 3 decuplet. We review how these particles provide a unified approach to major cosmological problems and we treat such current problems as the formation of stars and galaxies, the cosmic ray spectrum and the solar neutrino deficiency.
Thermonuclear fusion rates for particles of a single species are proportional to n2, where n is t... more Thermonuclear fusion rates for particles of a single species are proportional to n2, where n is the number density of the reacting particles. Standard magnetic confinement techniques employ relatively thin plasmas with n ≈ 1015 cm-3 and therefore require temperatures of the order of 108 K. We propose a method to exploit the n2 factor and hence to attain appreciable fusion rates at lower temperatures. We consider a dense gas of deuterium to undergo a rapid, adiabatic compression by a piston in an adiabatically insulated reaction chamber. A reduction in the degrees of freedom of the plasma particles, such as may be effected by an electric discharge during the compression or by application of suitably disposed external magnetic fields, results in a higher final temperature for a given energy input. In model calculations we consider the adiabatic compression of one mole of deuterium initially at room temperature and pressure and we compare the fusion energy release with the work done by...
Recent observations of Type Ia supernovae appear to suggest that the universe is accelerating. Th... more Recent observations of Type Ia supernovae appear to suggest that the universe is accelerating. These results are not only surprising but beyond the realm of any standard model of modern cosmology. Most of the new ideas proposed for understanding the acceleration include a new type of matter (dark energy or axions) or Einstein's cosmological constant. Although such attempts are reasonably successful in fitting the observed data, there is as yet no direct evidence to support the existence of such matter or energy. The present work examines whether the question of acceleration can be resolved within the limits of the established laws of physics. For this purpose we have calculated the contributions of Thomson scattering to the dimming of supernovae within the framework of Friedmann-Robertson-Walker cosmology for the special case of flat universe, also consistent with the prediction of the inflationary model. The results and conclusion of our investigation will be presented.
The report summarizes the work performed during FY 1967. After a brief description of the system ... more The report summarizes the work performed during FY 1967. After a brief description of the system and its characteristics, a number of background studies are described. Particular attention has been given to microbarographic pressure fluctuation levels (power spectra) and cross-spectral properties such as coherence and phase lags between pairs of instruments. It is found that an important fraction of the background, in the 5 to 50 min period range, consists of slowly traveling disturbances (20-40 m/sec) probably associated with the jet stream. This part of the background is coherent over distances of a few km, and decorrelates rapidly for distances greater than 10 km. This report also discusses briefly immediate plans for FY 1968. (Author)
Recent observations of distant type Ia supernovae indicate an acceleration in the expansion rate ... more Recent observations of distant type Ia supernovae indicate an acceleration in the expansion rate of the universe footnote R.A. Kerr, Science 279, 651 (1998). Specifically, distances inferred from observations of the apparent magnitudes of objects with z >=0.18 are found to deviate from those predicted by the Hubble law. To account for these deviations we employ a cosmological model proposed by Motz (L. Motz, Comments Astrophys. 13, 67 (1989)) in which the initial universe was dominated by Planck-mass particles. The gravitational attraction between these massive particles caused them to coalesce in triplets to form the present baryons and the attendant release of energy produced the big bang. Motz further proposed that the dark matter consists of relict particles which did not coalesce. We attribute the recent observations to the effects of energy released in the coalescence of relict particles. We calculate the work required to displace a body to a location other than that predic...
Measurements of distance to Type Ia supernovae have been interpreted as evidence for an accelerat... more Measurements of distance to Type Ia supernovae have been interpreted as evidence for an accelerating expansion of the Universe. There is, however, no known compatible theoretical framework to account for this effect. Proposed mechanisms include introduction of a new type of matter (``dark energy" or ``quintessence") or invocation of Einstein's cosmological constant which, in modern terms, corresponds to vacuum energy associated with quantum fluctuations. Yet there are no experimental observations to support the existence of such matter or energy associated with our Universe. The goal of the present work is to examine whether the conclusion that the Universe is accelerating is conclusive. Evidence for an accelerating expansion is based on measurements of the redshift and luminosity of supernovae billions of light years away. These measurements depend on the velocity of light which itself depends on the medium of propagation. Hence it is critical to analyze the propertie...
Since Tokamak devices require temperatures of the order of 10^8 K for their operation, it is temp... more Since Tokamak devices require temperatures of the order of 10^8 K for their operation, it is tempting to assume that appreciable nuclear fusion rates can be attained only at such high temperatures. However it may not be widely appreciated that fusion rates are proportional to the square of the particle density and that these temperature requirements result from use of relatively thin plasmas. We describe herein means to achieve high fusion rates at temperatures of only a few million K. Specifically we consider the compression by an explosively-driven piston of a dense plasma with reduced degrees of freedom such as may be effected by an electric discharge or by application of magnetic fields. Model calculations of the temperature increase employ one mole of deuterium initially at room temperature and pressure and assume an ideal gas undergoing a reversible adiabatic compression. The energy release computed for primary fusion reactions is compared with the work to compress the gas. Re...
It is widely held that quarks are conserved by flavor only in strong interactions. However this l... more It is widely held that quarks are conserved by flavor only in strong interactions. However this limitation appears to exist only because leptons are considered fundamental, i.e. particles with no structure. If we take conservation of quarks by flavor as a general principle, applicable to weak interactions as well as to strong interactions, we find leptons to be composite particles. We discuss implications for the structure of matter and for conservation laws.
Modern Physics Letters A, 1998
A mechanism is proposed for the emission of radiation by charged particles in the gravitational f... more A mechanism is proposed for the emission of radiation by charged particles in the gravitational field of a quasar whereby the gravitational field is coupled directly to the radiation field of the charge via the principle of equivalence. A generalized Larmor formula for the radiation emitted by a charge at rest in a gravitational field can account for the total radiant energy and spectral distribution emitted by quasars. This gravitational mechanism for the emission of electromagnetic radiation becomes more important than any other mechanism when the radius of the quasar is near its Schwarzschild radius.
The Journal of the Acoustical Society of America, 1974
A simple relation shown by White to exist between plane shear and compressional elastic waves und... more A simple relation shown by White to exist between plane shear and compressional elastic waves undergoing mode conversion when normally incident upon an empty or fluid-filled cylindrical scatterer is extended to include the case of a solid scatterer. The obstacle is assumed to be an infinitely long cylinder embedded in an infinite isotropic solid medium. A sign error in White's result is corrected.
Journal of Applied Physics, 1971
Measurements of ultrasonic attenuation due to the scattering of longitudinal elastic waves from a... more Measurements of ultrasonic attenuation due to the scattering of longitudinal elastic waves from a distribution of cavities in a solid medium are found to be consistent with theoretical predictions. Under certain conditions such measurements can be utilized to nondestructively characterize the size and number density of such a collection of scatterers.
Journal of Applied Physics, 1972
Cross sections are computed for the scattering of a plane transverse elastic wave by an elastic s... more Cross sections are computed for the scattering of a plane transverse elastic wave by an elastic sphere in an infinite isotropic homogeneous elastic solid. Analytic expressions are derived for the matrix elements indicated by Einspruch, Witterholt, and Truell, and the resulting matrix equations are solved numerically. The dependence of the scattering cross section upon K1a (K1 is the transverse propagation constant, a is the obstacle radius) over the range 0.01–10 is computed for various combinations of host and scatterer materials. The sensitivity of the cross section and its component terms to the elastic properties of the host and scatterer materials, and their behavior in the Rayleigh limit approximation are discussed. The calculations include the case of a constant host with a varying obstacle, and a constant scatterer in a varying host medium. It is found that most of the examples tested can be grouped conveniently into four classes, with a fifth category containing unstable re...
Journal of Applied Physics, 1976
The scattering of plane shear and compressional waves incident normally upon an infinitely long c... more The scattering of plane shear and compressional waves incident normally upon an infinitely long circular cylindrical obstacle in an isotropic homogeneous elastic solid medium is examined in the case in which the incident wavelength is large compared to the obstacle diameter. The scatterer can be either an empty cavity, a nonviscous-fluid-filled cavity, or an elastic solid cylinder. Explicit approximate expressions for the scattering cross sections are derived from the general theory formulated by White. The cross sections are proportional to (ka)3, where k is the compressional or shear wave-vector amplitude, and a is the cylinder radius.
Nucleation and Atmospheric Aerosols, 2004
It is proposed that when the era of the big-bang nucleosynthesis ended, almost all of the 75 perc... more It is proposed that when the era of the big-bang nucleosynthesis ended, almost all of the 75 percent of the observed total baryonic matter remained in the form of hydrogen and continued to exist in the form of protons and electrons. They are present today as baryonic dark matter in the form of intergalactic hydrogen plasma. To test our hypothesis we have investigated the effects of Thomson scattering by free electrons on the reported dimming of Type Ia supernovae. The quantitative results of our calculation suggest that the dimming of these supernovae, which are dimmer than expected and hence more distant than predicted by Hubble expansion, is a result of Thomson scattering without cosmic acceleration.
Bulletin of the American Physical Society, Nov 7, 2015
Primary cosmic rays are nucleons from outer space incident upon the Earth’s atmosphere. Their flu... more Primary cosmic rays are nucleons from outer space incident upon the Earth’s atmosphere. Their flux varies with energy E as \u1d438^(−\u1d6fe) in which the exponent assumes values between 2.5 and 3.2. We provide herein a framework to account for these values. We consider the particles’ kinetic temperature T and introduce a damping factor \u1d447^(−\u1d45a) to account for non head-on collisions. It is the presence of the index m which can provide values of γ
Bulletin of the American Physical Society, 2016
We study the evolution of asteroid orbits in a restricted three-body problem formulation consisti... more We study the evolution of asteroid orbits in a restricted three-body problem formulation consisting of the Sun, the planet Jupiter and an unspecified asteroid of negligible mass. It was discovered by Kirkwood [l] that the distribution of asteroid orbits contains gaps for orbits whose period is commensurate with that of Jupiter. Detailed computations in threedimensional, many-body formulations found that test bodies initially placed in a forbidden orbit did not develop large eccentricities or leave the gap even after the passage of 10 5 years [2]. In the present two-dimensional simulation, an extension of earlier work [3], we perform numerical integrations of the coupled equations of motion for Jupiter and the asteroid. Under assumptions of a stationary Sun and a circular orbit for Jupiter, we find that test bodies initially placed in a forbidden orbit can develop a large eccentricity after relatively few orbits.
Fusion Science and Technology, 2012
Energy is released when light nuclei fuse to form heavier nuclei. This is the energy which powers... more Energy is released when light nuclei fuse to form heavier nuclei. This is the energy which powers stars such as the Sun. The amount of energy released is related to the difference in the masses of the initial and final nuclei according to E = mc 2. Nuclear forces are of short range. Hence reactions occur only when nuclei are in close proximity and to achieve this they must have energy sufficient to overcome their repulsive electrostatic forces. This requires such high temperatures as 15,000,000 K as in the Sun.
The Physics Teacher, 1995
EJ518772 - Geometric Derivation of Radial Acceleration Magnitude.
Proceedings of the 2014 Zone 1 Conference of the American Society for Engineering Education, 2014
Treatments of the exponential function in Calculus textbooks are often cursory in that they treat... more Treatments of the exponential function in Calculus textbooks are often cursory in that they treat unchecked (Malthusian) growth processes without examination of their consequences. Through the use of problems posed to students, we illustrate the implications of such processes when applied to growth of populations and to growth in the rates of consumption of nonrenewable resources.
Causality and Locality in Modern Physics, 1998
The universal constants G, c and ħ comprise the Planck mass, (ћ c/G) 1/2 ≈ 10−5 g. We present arg... more The universal constants G, c and ħ comprise the Planck mass, (ћ c/G) 1/2 ≈ 10−5 g. We present arguments for the existence and properties of particles with this mass, describe how they serve as the constituents for a gravitational theory of matter, and explore the cosmological implications of this theory. Specifically, we describe a gravitational rotator model for baryons and show how this accounts for baryon stability and the three-quark saturation of baryons and that it predicts the Gell-Mann-Okubo mass formula for the SU 3 octet and the equal spacing rule for the SU 3 decuplet. We review how these particles provide a unified approach to major cosmological problems and we treat such current problems as the formation of stars and galaxies, the cosmic ray spectrum and the solar neutrino deficiency.
Thermonuclear fusion rates for particles of a single species are proportional to n2, where n is t... more Thermonuclear fusion rates for particles of a single species are proportional to n2, where n is the number density of the reacting particles. Standard magnetic confinement techniques employ relatively thin plasmas with n ≈ 1015 cm-3 and therefore require temperatures of the order of 108 K. We propose a method to exploit the n2 factor and hence to attain appreciable fusion rates at lower temperatures. We consider a dense gas of deuterium to undergo a rapid, adiabatic compression by a piston in an adiabatically insulated reaction chamber. A reduction in the degrees of freedom of the plasma particles, such as may be effected by an electric discharge during the compression or by application of suitably disposed external magnetic fields, results in a higher final temperature for a given energy input. In model calculations we consider the adiabatic compression of one mole of deuterium initially at room temperature and pressure and we compare the fusion energy release with the work done by...
Recent observations of Type Ia supernovae appear to suggest that the universe is accelerating. Th... more Recent observations of Type Ia supernovae appear to suggest that the universe is accelerating. These results are not only surprising but beyond the realm of any standard model of modern cosmology. Most of the new ideas proposed for understanding the acceleration include a new type of matter (dark energy or axions) or Einstein's cosmological constant. Although such attempts are reasonably successful in fitting the observed data, there is as yet no direct evidence to support the existence of such matter or energy. The present work examines whether the question of acceleration can be resolved within the limits of the established laws of physics. For this purpose we have calculated the contributions of Thomson scattering to the dimming of supernovae within the framework of Friedmann-Robertson-Walker cosmology for the special case of flat universe, also consistent with the prediction of the inflationary model. The results and conclusion of our investigation will be presented.
The report summarizes the work performed during FY 1967. After a brief description of the system ... more The report summarizes the work performed during FY 1967. After a brief description of the system and its characteristics, a number of background studies are described. Particular attention has been given to microbarographic pressure fluctuation levels (power spectra) and cross-spectral properties such as coherence and phase lags between pairs of instruments. It is found that an important fraction of the background, in the 5 to 50 min period range, consists of slowly traveling disturbances (20-40 m/sec) probably associated with the jet stream. This part of the background is coherent over distances of a few km, and decorrelates rapidly for distances greater than 10 km. This report also discusses briefly immediate plans for FY 1968. (Author)
Recent observations of distant type Ia supernovae indicate an acceleration in the expansion rate ... more Recent observations of distant type Ia supernovae indicate an acceleration in the expansion rate of the universe footnote R.A. Kerr, Science 279, 651 (1998). Specifically, distances inferred from observations of the apparent magnitudes of objects with z >=0.18 are found to deviate from those predicted by the Hubble law. To account for these deviations we employ a cosmological model proposed by Motz (L. Motz, Comments Astrophys. 13, 67 (1989)) in which the initial universe was dominated by Planck-mass particles. The gravitational attraction between these massive particles caused them to coalesce in triplets to form the present baryons and the attendant release of energy produced the big bang. Motz further proposed that the dark matter consists of relict particles which did not coalesce. We attribute the recent observations to the effects of energy released in the coalescence of relict particles. We calculate the work required to displace a body to a location other than that predic...
Measurements of distance to Type Ia supernovae have been interpreted as evidence for an accelerat... more Measurements of distance to Type Ia supernovae have been interpreted as evidence for an accelerating expansion of the Universe. There is, however, no known compatible theoretical framework to account for this effect. Proposed mechanisms include introduction of a new type of matter (``dark energy" or ``quintessence") or invocation of Einstein's cosmological constant which, in modern terms, corresponds to vacuum energy associated with quantum fluctuations. Yet there are no experimental observations to support the existence of such matter or energy associated with our Universe. The goal of the present work is to examine whether the conclusion that the Universe is accelerating is conclusive. Evidence for an accelerating expansion is based on measurements of the redshift and luminosity of supernovae billions of light years away. These measurements depend on the velocity of light which itself depends on the medium of propagation. Hence it is critical to analyze the propertie...
Since Tokamak devices require temperatures of the order of 10^8 K for their operation, it is temp... more Since Tokamak devices require temperatures of the order of 10^8 K for their operation, it is tempting to assume that appreciable nuclear fusion rates can be attained only at such high temperatures. However it may not be widely appreciated that fusion rates are proportional to the square of the particle density and that these temperature requirements result from use of relatively thin plasmas. We describe herein means to achieve high fusion rates at temperatures of only a few million K. Specifically we consider the compression by an explosively-driven piston of a dense plasma with reduced degrees of freedom such as may be effected by an electric discharge or by application of magnetic fields. Model calculations of the temperature increase employ one mole of deuterium initially at room temperature and pressure and assume an ideal gas undergoing a reversible adiabatic compression. The energy release computed for primary fusion reactions is compared with the work to compress the gas. Re...
It is widely held that quarks are conserved by flavor only in strong interactions. However this l... more It is widely held that quarks are conserved by flavor only in strong interactions. However this limitation appears to exist only because leptons are considered fundamental, i.e. particles with no structure. If we take conservation of quarks by flavor as a general principle, applicable to weak interactions as well as to strong interactions, we find leptons to be composite particles. We discuss implications for the structure of matter and for conservation laws.
Modern Physics Letters A, 1998
A mechanism is proposed for the emission of radiation by charged particles in the gravitational f... more A mechanism is proposed for the emission of radiation by charged particles in the gravitational field of a quasar whereby the gravitational field is coupled directly to the radiation field of the charge via the principle of equivalence. A generalized Larmor formula for the radiation emitted by a charge at rest in a gravitational field can account for the total radiant energy and spectral distribution emitted by quasars. This gravitational mechanism for the emission of electromagnetic radiation becomes more important than any other mechanism when the radius of the quasar is near its Schwarzschild radius.
The Journal of the Acoustical Society of America, 1974
A simple relation shown by White to exist between plane shear and compressional elastic waves und... more A simple relation shown by White to exist between plane shear and compressional elastic waves undergoing mode conversion when normally incident upon an empty or fluid-filled cylindrical scatterer is extended to include the case of a solid scatterer. The obstacle is assumed to be an infinitely long cylinder embedded in an infinite isotropic solid medium. A sign error in White's result is corrected.
Journal of Applied Physics, 1971
Measurements of ultrasonic attenuation due to the scattering of longitudinal elastic waves from a... more Measurements of ultrasonic attenuation due to the scattering of longitudinal elastic waves from a distribution of cavities in a solid medium are found to be consistent with theoretical predictions. Under certain conditions such measurements can be utilized to nondestructively characterize the size and number density of such a collection of scatterers.
Journal of Applied Physics, 1972
Cross sections are computed for the scattering of a plane transverse elastic wave by an elastic s... more Cross sections are computed for the scattering of a plane transverse elastic wave by an elastic sphere in an infinite isotropic homogeneous elastic solid. Analytic expressions are derived for the matrix elements indicated by Einspruch, Witterholt, and Truell, and the resulting matrix equations are solved numerically. The dependence of the scattering cross section upon K1a (K1 is the transverse propagation constant, a is the obstacle radius) over the range 0.01–10 is computed for various combinations of host and scatterer materials. The sensitivity of the cross section and its component terms to the elastic properties of the host and scatterer materials, and their behavior in the Rayleigh limit approximation are discussed. The calculations include the case of a constant host with a varying obstacle, and a constant scatterer in a varying host medium. It is found that most of the examples tested can be grouped conveniently into four classes, with a fifth category containing unstable re...
Journal of Applied Physics, 1976
The scattering of plane shear and compressional waves incident normally upon an infinitely long c... more The scattering of plane shear and compressional waves incident normally upon an infinitely long circular cylindrical obstacle in an isotropic homogeneous elastic solid medium is examined in the case in which the incident wavelength is large compared to the obstacle diameter. The scatterer can be either an empty cavity, a nonviscous-fluid-filled cavity, or an elastic solid cylinder. Explicit approximate expressions for the scattering cross sections are derived from the general theory formulated by White. The cross sections are proportional to (ka)3, where k is the compressional or shear wave-vector amplitude, and a is the cylinder radius.