ltw public reporting burden foi (Mi collection of information «s estimated to swag* ' nour per re... more ltw public reporting burden foi (Mi collection of information «s estimated to swag* ' nour per response <nrntr1mg the time (or reviewing msttuctinnt Kaarchmg existing data sources gathering and maintaining the data needed, end completing end reviewing the collection o* information. Send comments legerding this ourden eshmeie or any other aspect o' this collection (if information, mclud.ng »ogge*tmn» lor reducing the burden to the Deportment ol Defense fcxecutrve Services end Communicaiions Directorate (0704-01881. Respondent* should be aware th«t nptwithstanding any other proviston ol lew. no person shall be subject to any [wneUv (or f*krtg to comniv with • .-.oBectw of irrformatHm tf it does not thaptey • Current** «eJaj OMB control number
The circuit equations for the inductor driven rail launcher are integrated numerically using a fo... more The circuit equations for the inductor driven rail launcher are integrated numerically using a fourth order Runge-Kutta method. Their solution is also obtained as a perturbation expansion for small resistance. The EMACK parameters are used to study the results. For high current shots the full numerical solution agress with the first order approximation to 3%. For low current shots they agree to 5%. A very simple zeroth order approximation agress with the full numerical solution to 5% in the high current case and to 3% in the low current case.
Our paper in the Astrophysical Journal, vol. 596, pp. 646-655 presented the results of our one di... more Our paper in the Astrophysical Journal, vol. 596, pp. 646-655 presented the results of our one dimensional computations using an adiabatic energy equation and an FCT algorithm. Those results showed that strong plane polarized Alfvén waves that propagate along magnetic field lines up into the solar corona can develop into MHD shocks and act as a significant mechanism for coronal
The researchers present a calculation in a simplified geometry for the current distribution in th... more The researchers present a calculation in a simplified geometry for the current distribution in the rails, taking into account the motion of the armature and the time variation of the current. Closed form, asymptotic, results for the current density are obtained for arbitrary time dependent electrical conductivity of the rails, and upsilon is the speed of the armature. Because of eddy current effects the rail current may reverse in portions of the rails when the total current decreases. The current is used as a source of Joule heating to find the temperature distribution in the rails. The heat diffusivity is negligible and give numerical results concerning melting.
The purpose of this paper is to begin to investigate the use of the commercial particle in cell (... more The purpose of this paper is to begin to investigate the use of the commercial particle in cell (PIC) code MAGIC for simulations of Dielectric Barrier Discharges (DBD). We only treat discharges of very short duration in pure N2 at atmospheric pressure. The only particle creation - ...
Exact closed-form expressions for the Fresnel region electric and magnetic fields of circular loo... more Exact closed-form expressions for the Fresnel region electric and magnetic fields of circular loop and annular slot antennas are given in terms of the functions en(σ,Γ)=(1∕2π)02π cos(n&PHgr;) sin[σ(1–2Γ cos&PHgr;)1∕2] d&PHgr; and fn(σ,Γ)=(1∕2π)02π cos(n&PHgr;) cos[σ(1–2Γ cos&PHgr;)1∕2] d&PHgr;, where - ∞ < σ < ∞ and 0 ≤ Γ ≤ 1∕2. For a circular loope antenna with a constant current distribution the Fresnel region fields are obtained in terms of the functions qn (σ,Γ)=fn (σ,Γ)+ien(σ,Γ), with n =0,1, and 2, and for a cosine current distribution the Fresnel region fields are obtained in terms of the functions qn(σ,Γ), with n =0,1,2,3, and 4. The magnetic field of an annular slot antenna excited by a constant voltage is expressed exactly in terms of an infinite series involving the functions qn (σ,Γ). The Fresnel region magnetic field of the annular slot antenna is simply given in terms of q1(σ,Γ). The functions qn(σ,Γ) permitted a simple evaluation of the electric and magnetic field strength in the Fresnel region. The functions qn(σ,Γ) for n =0,1,2,3, and 4 are tabulated for values of σ=0.5, 1, 2, 5, 10, 25, and 50 and values of Γ from 0.01 to 0.5.
... Theoretical and cxperiment.al investigations huvo been conducted (Brody et (/1. I!ln, Geisler... more ... Theoretical and cxperiment.al investigations huvo been conducted (Brody et (/1. I!ln, Geisler and Gerstein l!l(jI, Hosek ei ul . I!l7S, Schneider I!J74) to enhance the interprcta.t.ion of informa.tion obtained from surface potentials. ...
The exact Green&#x27;s function solution for the surface potential produced by a point dipole... more The exact Green&#x27;s function solution for the surface potential produced by a point dipole current source immersed in a stratified prolate spheroidal or spherical volume conductor is given. The transmission matrix approach used allows a systematic calculation for any number of stratifications or dipole locations. Numerical results are given for prolate spheroidal and spherical models of the human head.
ABSTRACT The Euler equations for a reacting polytropic gas with model losses, applied to unsuppor... more ABSTRACT The Euler equations for a reacting polytropic gas with model losses, applied to unsupported steady detonation waves, lead to fast and slow detonation speeds for a given loss. The reaction rate is taken to have the Arrhenius form. The differential equations for the Mach number squared m and the reaction progress variable lambda are integrated numerically using a fourth-order Runge-Kutta-Fehlberg method. The calculations are presented as plots of trajectories in the lambda-log(m) plane. The main parameters that are varied are the activation temperature, the heat of reaction, the order of the reaction, and the polytropic exponent gamma. The onset of detonation failure, and a continuum of solutions that appears in some parameter ranges, are explored in detail. The results are summarized in plots of the detonation Mach number squared m0 versus the logarithm of the loss parameter.
Este trabajo tiene por objeto mostrar los avances de un proyecto de investigación más amplio que ... more Este trabajo tiene por objeto mostrar los avances de un proyecto de investigación más amplio que se encuentra en la fase experimental. Se discute la noción de mapa conceptual y se reinterpreta desde las matemáticas, se revisa el estado de la investigación sobre esta herramienta y sus usos para la investigación en Educación Matemática y se expone, finalmente, la fase experimental del proyecto, haciendo hincapié en los participantes y en los objetivos. Se incluye un conjunto abundante de referencias que dan cuenta de los mapas conceptuales en la investigación, en contextos diferentes. VI Simposio de la SEIEM 225 Los mapas conceptuales en Educación Matemática Los mapas conceptuales en Educación Matemática 236 Los mapas conceptuales en Educación Matemática
The formation of orderly, steady, spatial structures in rf-heated plasmas that have metastable st... more The formation of orderly, steady, spatial structures in rf-heated plasmas that have metastable states is studied as the development of an instability of the solution to the reaction-diffusion equations for the plasma species. Plasma-species (electrons, ions, and metastable atoms) source functions are given in terms of the electron energy distribution in strong electric fields and of the various collision cross sections. The methods of two-time expansions and bifurcation theory are used to calculate the nonuniform states that bifurcate from the unstable uniform steady state for straight and toroidal tubes. The sinusoidal density variations give the discharge the appearance of glowing balls of gas. This pattern formation is analogous to the morphogenesis found in certain chemical reactions and biological processes.
ltw public reporting burden foi (Mi collection of information «s estimated to swag* ' nour per re... more ltw public reporting burden foi (Mi collection of information «s estimated to swag* ' nour per response <nrntr1mg the time (or reviewing msttuctinnt Kaarchmg existing data sources gathering and maintaining the data needed, end completing end reviewing the collection o* information. Send comments legerding this ourden eshmeie or any other aspect o' this collection (if information, mclud.ng »ogge*tmn» lor reducing the burden to the Deportment ol Defense fcxecutrve Services end Communicaiions Directorate (0704-01881. Respondent* should be aware th«t nptwithstanding any other proviston ol lew. no person shall be subject to any [wneUv (or f*krtg to comniv with • .-.oBectw of irrformatHm tf it does not thaptey • Current** «eJaj OMB control number
The circuit equations for the inductor driven rail launcher are integrated numerically using a fo... more The circuit equations for the inductor driven rail launcher are integrated numerically using a fourth order Runge-Kutta method. Their solution is also obtained as a perturbation expansion for small resistance. The EMACK parameters are used to study the results. For high current shots the full numerical solution agress with the first order approximation to 3%. For low current shots they agree to 5%. A very simple zeroth order approximation agress with the full numerical solution to 5% in the high current case and to 3% in the low current case.
Our paper in the Astrophysical Journal, vol. 596, pp. 646-655 presented the results of our one di... more Our paper in the Astrophysical Journal, vol. 596, pp. 646-655 presented the results of our one dimensional computations using an adiabatic energy equation and an FCT algorithm. Those results showed that strong plane polarized Alfvén waves that propagate along magnetic field lines up into the solar corona can develop into MHD shocks and act as a significant mechanism for coronal
The researchers present a calculation in a simplified geometry for the current distribution in th... more The researchers present a calculation in a simplified geometry for the current distribution in the rails, taking into account the motion of the armature and the time variation of the current. Closed form, asymptotic, results for the current density are obtained for arbitrary time dependent electrical conductivity of the rails, and upsilon is the speed of the armature. Because of eddy current effects the rail current may reverse in portions of the rails when the total current decreases. The current is used as a source of Joule heating to find the temperature distribution in the rails. The heat diffusivity is negligible and give numerical results concerning melting.
The purpose of this paper is to begin to investigate the use of the commercial particle in cell (... more The purpose of this paper is to begin to investigate the use of the commercial particle in cell (PIC) code MAGIC for simulations of Dielectric Barrier Discharges (DBD). We only treat discharges of very short duration in pure N2 at atmospheric pressure. The only particle creation - ...
Exact closed-form expressions for the Fresnel region electric and magnetic fields of circular loo... more Exact closed-form expressions for the Fresnel region electric and magnetic fields of circular loop and annular slot antennas are given in terms of the functions en(σ,Γ)=(1∕2π)02π cos(n&PHgr;) sin[σ(1–2Γ cos&PHgr;)1∕2] d&PHgr; and fn(σ,Γ)=(1∕2π)02π cos(n&PHgr;) cos[σ(1–2Γ cos&PHgr;)1∕2] d&PHgr;, where - ∞ < σ < ∞ and 0 ≤ Γ ≤ 1∕2. For a circular loope antenna with a constant current distribution the Fresnel region fields are obtained in terms of the functions qn (σ,Γ)=fn (σ,Γ)+ien(σ,Γ), with n =0,1, and 2, and for a cosine current distribution the Fresnel region fields are obtained in terms of the functions qn(σ,Γ), with n =0,1,2,3, and 4. The magnetic field of an annular slot antenna excited by a constant voltage is expressed exactly in terms of an infinite series involving the functions qn (σ,Γ). The Fresnel region magnetic field of the annular slot antenna is simply given in terms of q1(σ,Γ). The functions qn(σ,Γ) permitted a simple evaluation of the electric and magnetic field strength in the Fresnel region. The functions qn(σ,Γ) for n =0,1,2,3, and 4 are tabulated for values of σ=0.5, 1, 2, 5, 10, 25, and 50 and values of Γ from 0.01 to 0.5.
... Theoretical and cxperiment.al investigations huvo been conducted (Brody et (/1. I!ln, Geisler... more ... Theoretical and cxperiment.al investigations huvo been conducted (Brody et (/1. I!ln, Geisler and Gerstein l!l(jI, Hosek ei ul . I!l7S, Schneider I!J74) to enhance the interprcta.t.ion of informa.tion obtained from surface potentials. ...
The exact Green&#x27;s function solution for the surface potential produced by a point dipole... more The exact Green&#x27;s function solution for the surface potential produced by a point dipole current source immersed in a stratified prolate spheroidal or spherical volume conductor is given. The transmission matrix approach used allows a systematic calculation for any number of stratifications or dipole locations. Numerical results are given for prolate spheroidal and spherical models of the human head.
ABSTRACT The Euler equations for a reacting polytropic gas with model losses, applied to unsuppor... more ABSTRACT The Euler equations for a reacting polytropic gas with model losses, applied to unsupported steady detonation waves, lead to fast and slow detonation speeds for a given loss. The reaction rate is taken to have the Arrhenius form. The differential equations for the Mach number squared m and the reaction progress variable lambda are integrated numerically using a fourth-order Runge-Kutta-Fehlberg method. The calculations are presented as plots of trajectories in the lambda-log(m) plane. The main parameters that are varied are the activation temperature, the heat of reaction, the order of the reaction, and the polytropic exponent gamma. The onset of detonation failure, and a continuum of solutions that appears in some parameter ranges, are explored in detail. The results are summarized in plots of the detonation Mach number squared m0 versus the logarithm of the loss parameter.
Este trabajo tiene por objeto mostrar los avances de un proyecto de investigación más amplio que ... more Este trabajo tiene por objeto mostrar los avances de un proyecto de investigación más amplio que se encuentra en la fase experimental. Se discute la noción de mapa conceptual y se reinterpreta desde las matemáticas, se revisa el estado de la investigación sobre esta herramienta y sus usos para la investigación en Educación Matemática y se expone, finalmente, la fase experimental del proyecto, haciendo hincapié en los participantes y en los objetivos. Se incluye un conjunto abundante de referencias que dan cuenta de los mapas conceptuales en la investigación, en contextos diferentes. VI Simposio de la SEIEM 225 Los mapas conceptuales en Educación Matemática Los mapas conceptuales en Educación Matemática 236 Los mapas conceptuales en Educación Matemática
The formation of orderly, steady, spatial structures in rf-heated plasmas that have metastable st... more The formation of orderly, steady, spatial structures in rf-heated plasmas that have metastable states is studied as the development of an instability of the solution to the reaction-diffusion equations for the plasma species. Plasma-species (electrons, ions, and metastable atoms) source functions are given in terms of the electron energy distribution in strong electric fields and of the various collision cross sections. The methods of two-time expansions and bifurcation theory are used to calculate the nonuniform states that bifurcate from the unstable uniform steady state for straight and toroidal tubes. The sinusoidal density variations give the discharge the appearance of glowing balls of gas. This pattern formation is analogous to the morphogenesis found in certain chemical reactions and biological processes.
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Papers by Manuel Huerta