Kailash Kumar - Academia.edu (original) (raw)

Papers by Kailash Kumar

Australian Journal of Physics, 1966

An expression is given for the integral over the domain of Euler angles of a product of any numbe... more An expression is given for the integral over the domain of Euler angles of a product of any number of rotation matrices. As a result a scheme has been set up in which any number of angular momenta may be coupled on an equal footing. Explicit algebraic exp

Il Nuovo Cimento, 1959

SummaryThe nucleus is treated as a Fermi gas under the constraint of a given angular momentumI. I... more SummaryThe nucleus is treated as a Fermi gas under the constraint of a given angular momentumI. Its energy is expressed as a power series inI2, and the rotational and rotation-vibration interaction terms are identified. The interparticle interactions do not influence the rotational energies whereas they have important influence on the rotation-vibration energies. Several models for angular momentum production are considered. The experimental trend of the moments of inertia is reproduced by a model in which only nucleons outside a certain «core» produce the total angular momentum. The vibrational frequency is insensitive to such models. The surface effects and the influence of velocity dependent forces are also taken into account.RiassuntoSi tratta il nucleo come un gas di Fermi con l’imposizione di un dato impulso angolareI. Si esprime la sua energia come una serie di potenze inI2 e si identificano i termini d’interazione rotazionali e vibrorotazionali. Le interazioni fra particelle non influsicono sulle energie rotazionali, mentre agiscono in modo rilevante sulle energie vibrorotazionali. Si considerano vari modelli per la produzione degli impulsi angolari. La tendenza dei momenti d’inerzia risultante sperimentalmente è riprodotta da un modello in cui solo i nucleoni esterni a un determinato «core» producono l’impulso angolare totale. La frequenza vibrazionale non è influenzata da tale modello. Si tiene anche conto degli effetti superficiali e dell’influenza delle forze dipendenti dalla velocità.

Physics Reports, 1984

Introduction 321 2.3. Kinetic equations for transport coefficients and the 0.1. General 321 metho... more Introduction 321 2.3. Kinetic equations for transport coefficients and the 0.1. General 321 methods of solving them 341 0.2. A historical sketch 323 2.4. Representations of the collision operator 345 1. Principles of experiments and phenomenological descrip-2.5. Some results from applications: cross-sections, distion 326 tribution functions and potentials 354 1.1. Measurement of drift and longitudinal diffusion 327 2.6. Nonhydrodynamic effects 356 1.2. Direct measurement of diffusion: Cavalleri's experi-3. Finite enclosure and boundary effects 361 ment 329 3,1. The two-term approximation 361 1.3. Transverse diffusion: Townsend-Huxley steady-state 3.2. Finite enclosure without field: diffusion cooling 363 experiment 330 3.3, Boundary problem in presence of fields 364 1.4. lonisation, attachment and reaction processes 331 4. Theory of swarms in a finite enclosure 366 1.5. Phenomenological description 331 4.1. Physical boundaries and boundary conditions 366 2. Kinetic theory of swarms in free space 333 4.2. The Boltzmann equation for a finite enclosure 367 2.1. Outline of the general theory 333 5. Conclusions 371 2.2. Qualitative considerations 335 References 373

Australian Journal of Physics, 1973

The conditions that usually prevail in drift tube experiments for the measurement of mobility and... more The conditions that usually prevail in drift tube experiments for the measurement of mobility and diffusion of electron and ion swarms are appropriate for the application of a linearized Boltzmann equation. Starting from such an equation, formulae for mobility and (anisotropic) diffusion coefficients are derived for the case where only elastic collisions are important. No restriction is placed on the masses of particles or on the nature of interaction potential. Results of earlier theories are shown to be special cases of the formulae obtained here. The intended application of the equations is mainly to the case of alkali metal ions in neutral rare gases, where numerical evaluation of the formulae is necessary. The m!lin features of some of the numerical procedures are discussed.

Australian Journal of Physics, 1980

The kinetic theory of charged test particles in a neutral gas, in the presence of static and unif... more The kinetic theory of charged test particles in a neutral gas, in the presence of static and uniform electric and magnetic fields, is reviewed. The effects of inelastic processes and reactions are included. The general space-time development of the swarms is considered and the relation between the nonhydrodynamic anQ hydrodynamic developments is pointed out. The transport coefficients are identified as statistical averages over the configuration-space and phase-space distributions. The evaluation of these averages by computer simulations is briefly discussed.

Australian Journal of Physics, 1980

Polynomials of a three-dimensional vector x, orthogonal with respect to a weight function ~exp( -... more Polynomials of a three-dimensional vector x, orthogonal with respect to a weight function ~exp( -tx2) and expressed in spherical polar coordinates, are called Burnett functions. The matrix relating the Burnett functions of x = IX(C- W) to those of c is constructed for the case where IX is a real nonsingular 3 x 3 matrix and W is a real vector. These matrices are infinite dimensional, block lower triangular representations of the group whose elements (IX, W) satisfy the composition law

Australian Journal of Physics, 1995

The transport theory of swarms in a time dependent electric field is formulated in terms of the B... more The transport theory of swarms in a time dependent electric field is formulated in terms of the Boltzmann equation expressed as an integral equation in time. It allows for a convenient physical description of the time development of the swarm for the case of a periodically time dependent field. The exact solution of the ideal charge transfer or BGK model, obtained earlier by Robson and Makabe, is expressed in a closed form.

Australian Journal of Physics, 1975

Starting from the two-term approximation to the Boltzmann equation, a study is made of the time d... more Starting from the two-term approximation to the Boltzmann equation, a study is made of the time dependence of the density of electrons released inside a finite enclosure containing a neutral gas. The dominant behaviour can be represented by a diffusion equation containing an effective diffusion constant which depends upon pressure and dimensions of the enclosure. In the limit of large pressure and large enclosure the usual expression of the diffusion constant is obtained. The approach to this limit dePends upon the electron-neutral interaction. The effect of various model and measured cross sections for some inert gases is discussed.

Australian Journal of Physics, 1974

Baxter's method of solving the eight-vertex model in lattice statistical mechanics is examine... more Baxter's method of solving the eight-vertex model in lattice statistical mechanics is examined from an elementary point of view. It is shown that the algebraic operations in the method can be carried out without recourse to elliptic functions. These include: construction of certain subspaces invariant uti.der the action of the transfer matrix; reduction of the transfer matrix eigenvalue problem to an equivalent ice-type problem and construction of certain matrices which commute with the transfer matrix and satisfy a functional matrix equation.

Nuclear Physics, 1958

The contribution of the strong hyperon-K-meson-nucleon interaction to the nucleon magnetic moment... more The contribution of the strong hyperon-K-meson-nucleon interaction to the nucleon magnetic moment has been calculated, to the first order. In order to fit. the observed values with pseudoscalar K-mesons one needs gars/4x _ 9.6 and gxNY2 /gpr 2 = 0.06. If, however, the K-meson is assumed to be scalar, the last ratio becomes 0.016, which is perhaps too small, and g~re!4n in this case is 11 .3 .

Physical Review, 1956

Certain symmetry arguments have been used to suggest that the beta-decay interaction is S-T+P. It... more Certain symmetry arguments have been used to suggest that the beta-decay interaction is S-T+P. It is shown that if the negative electron in these arguments is replaced by the positron, the result is S+T+P and that the proposed symmetries do not lead to Hermitian Hamiltonians which treat negatrons and positrons on the same footing.

Physical Review, 1957

The methods of calculating the energy levels in spheroidal nuclei are discussed. It is shown that... more The methods of calculating the energy levels in spheroidal nuclei are discussed. It is shown that the expansion of the perturbation in powers of the deformation parameter, beta, leads to a very slowly convergent series representation of the matrix elements. An alternative method of expressing the perturbation, due to Moszkowski, which can allow a better calculation, is also discussed.

Swarm Studies and Inelastic Electron-Molecule Collisions, 1987

The effect of boundaries and finite enclosures on swarms has been the subject of a number of stud... more The effect of boundaries and finite enclosures on swarms has been the subject of a number of studies. We recall the work on electrons from a steady source incident on a planeabsorbing boundary [1], on diffusion cooling of electrons in finite enclosures [2], on attachment cooling [3] and on pressure dependence of mobility of ions (or runaway ions)[4]. The study of retarding potential difference analysis of the ion distribution function [5], and the considerations presented in the preceding talk by Tagashira [6], are also related to such effects.

The Journal of Infection in Developing Countries, 2013

Introduction: It is important to identify Salmonella Typhi infection quickly to treat acute fever... more Introduction: It is important to identify Salmonella Typhi infection quickly to treat acute fever patients and to prevent transmission by chronic typhoid carriers; therefore, a very specific and sensitive diagnostic technique is highly desirable, especially in endemic areas. The objective of this study was to develop a PCR protocol targeting the putative fimbrial staA gene of S. Typhi. This is a preferred target gene that is specifically amplified in the S. Typhi serotype compared to the commonly targeted fliC gene which may also be amplified from the non-typhoidal Salmonella Munchen serotype. Methodology: A new nested PCR primer methodology was designed to target the staA gene, which is a member of the fimbrial gene family specific to Salmonella Typhi only. Results: The primers were found to be very specific as the desired amplicon (377 bp) could be generated exclusively from S. Typhi strains including the reference strain (MTCC 3216) and 78 clinical isolates . Restriction digestio...

Nuclear Physics, 1963

A generalised Fermi-Thomas method, in which Kmatrices are used to obtain ; the potential energy, ... more A generalised Fermi-Thomas method, in which Kmatrices are used to obtain ; the potential energy, is used to calculate the energies and density distributions ; of nuclei for all mass values. It is shown that satisfactory agreement with the ; known empirical values, neglecting small shell effects, can be obtained but the ; corresponding Kmatrices will differ from those given

Nuclear Physics, 1964

Abstract The approximations involved in obtaining a Fermi-Thomas type of theory for nuclei are he... more Abstract The approximations involved in obtaining a Fermi-Thomas type of theory for nuclei are here related to the structure of the single-particle density matrix. Cases of both uniform and varying density are discussed.

Physical Review, 1961

The Hartree-Fock to Fermi-Thomas reduction is carried through for finite nuclei, starting with th... more The Hartree-Fock to Fermi-Thomas reduction is carried through for finite nuclei, starting with the iT-matrix formulation. The resulting expression represents the nuclear energy to good accuracy in terms of the density and its first derivatives only; it differs in detail from the semiempirical expressions previously proposed for this purpose. This improved expression shows the inadequacy of the "semi-infinite" approximation used often in earlier studies.

Vacuum, 1967

232 235 (f) Completion of the second approximation: Navier-Stokes equations 235 (g) General schem... more 232 235 (f) Completion of the second approximation: Navier-Stokes equations 235 (g) General scheme of the Chapman-Enskog method 236

Journal of the Physical Society of Japan, 1995

The basic formulation of the flight-time-integral method of Ikuta and coworkers is examined from ... more The basic formulation of the flight-time-integral method of Ikuta and coworkers is examined from a physical point of view. It is shown that if all equivalent flights are treated on an equal footing some corrections are needed. The content of the method then becomes the same as that of the path-integral method and therefore connection can also be made with the gradient expansion method. The expression for the drift velocity obtained in the flight-time-integral method is in agreement with that obtained from other methods and after some correction the expression for the diffusion coefficient can also be made to agree.

Australian Journal of Physics, 1966

An expression is given for the integral over the domain of Euler angles of a product of any numbe... more An expression is given for the integral over the domain of Euler angles of a product of any number of rotation matrices. As a result a scheme has been set up in which any number of angular momenta may be coupled on an equal footing. Explicit algebraic exp

Il Nuovo Cimento, 1959

SummaryThe nucleus is treated as a Fermi gas under the constraint of a given angular momentumI. I... more SummaryThe nucleus is treated as a Fermi gas under the constraint of a given angular momentumI. Its energy is expressed as a power series inI2, and the rotational and rotation-vibration interaction terms are identified. The interparticle interactions do not influence the rotational energies whereas they have important influence on the rotation-vibration energies. Several models for angular momentum production are considered. The experimental trend of the moments of inertia is reproduced by a model in which only nucleons outside a certain «core» produce the total angular momentum. The vibrational frequency is insensitive to such models. The surface effects and the influence of velocity dependent forces are also taken into account.RiassuntoSi tratta il nucleo come un gas di Fermi con l’imposizione di un dato impulso angolareI. Si esprime la sua energia come una serie di potenze inI2 e si identificano i termini d’interazione rotazionali e vibrorotazionali. Le interazioni fra particelle non influsicono sulle energie rotazionali, mentre agiscono in modo rilevante sulle energie vibrorotazionali. Si considerano vari modelli per la produzione degli impulsi angolari. La tendenza dei momenti d’inerzia risultante sperimentalmente è riprodotta da un modello in cui solo i nucleoni esterni a un determinato «core» producono l’impulso angolare totale. La frequenza vibrazionale non è influenzata da tale modello. Si tiene anche conto degli effetti superficiali e dell’influenza delle forze dipendenti dalla velocità.

Physics Reports, 1984

Introduction 321 2.3. Kinetic equations for transport coefficients and the 0.1. General 321 metho... more Introduction 321 2.3. Kinetic equations for transport coefficients and the 0.1. General 321 methods of solving them 341 0.2. A historical sketch 323 2.4. Representations of the collision operator 345 1. Principles of experiments and phenomenological descrip-2.5. Some results from applications: cross-sections, distion 326 tribution functions and potentials 354 1.1. Measurement of drift and longitudinal diffusion 327 2.6. Nonhydrodynamic effects 356 1.2. Direct measurement of diffusion: Cavalleri's experi-3. Finite enclosure and boundary effects 361 ment 329 3,1. The two-term approximation 361 1.3. Transverse diffusion: Townsend-Huxley steady-state 3.2. Finite enclosure without field: diffusion cooling 363 experiment 330 3.3, Boundary problem in presence of fields 364 1.4. lonisation, attachment and reaction processes 331 4. Theory of swarms in a finite enclosure 366 1.5. Phenomenological description 331 4.1. Physical boundaries and boundary conditions 366 2. Kinetic theory of swarms in free space 333 4.2. The Boltzmann equation for a finite enclosure 367 2.1. Outline of the general theory 333 5. Conclusions 371 2.2. Qualitative considerations 335 References 373

Australian Journal of Physics, 1973

The conditions that usually prevail in drift tube experiments for the measurement of mobility and... more The conditions that usually prevail in drift tube experiments for the measurement of mobility and diffusion of electron and ion swarms are appropriate for the application of a linearized Boltzmann equation. Starting from such an equation, formulae for mobility and (anisotropic) diffusion coefficients are derived for the case where only elastic collisions are important. No restriction is placed on the masses of particles or on the nature of interaction potential. Results of earlier theories are shown to be special cases of the formulae obtained here. The intended application of the equations is mainly to the case of alkali metal ions in neutral rare gases, where numerical evaluation of the formulae is necessary. The m!lin features of some of the numerical procedures are discussed.

Australian Journal of Physics, 1980

The kinetic theory of charged test particles in a neutral gas, in the presence of static and unif... more The kinetic theory of charged test particles in a neutral gas, in the presence of static and uniform electric and magnetic fields, is reviewed. The effects of inelastic processes and reactions are included. The general space-time development of the swarms is considered and the relation between the nonhydrodynamic anQ hydrodynamic developments is pointed out. The transport coefficients are identified as statistical averages over the configuration-space and phase-space distributions. The evaluation of these averages by computer simulations is briefly discussed.

Australian Journal of Physics, 1980

Polynomials of a three-dimensional vector x, orthogonal with respect to a weight function ~exp( -... more Polynomials of a three-dimensional vector x, orthogonal with respect to a weight function ~exp( -tx2) and expressed in spherical polar coordinates, are called Burnett functions. The matrix relating the Burnett functions of x = IX(C- W) to those of c is constructed for the case where IX is a real nonsingular 3 x 3 matrix and W is a real vector. These matrices are infinite dimensional, block lower triangular representations of the group whose elements (IX, W) satisfy the composition law

Australian Journal of Physics, 1995

The transport theory of swarms in a time dependent electric field is formulated in terms of the B... more The transport theory of swarms in a time dependent electric field is formulated in terms of the Boltzmann equation expressed as an integral equation in time. It allows for a convenient physical description of the time development of the swarm for the case of a periodically time dependent field. The exact solution of the ideal charge transfer or BGK model, obtained earlier by Robson and Makabe, is expressed in a closed form.

Australian Journal of Physics, 1975

Starting from the two-term approximation to the Boltzmann equation, a study is made of the time d... more Starting from the two-term approximation to the Boltzmann equation, a study is made of the time dependence of the density of electrons released inside a finite enclosure containing a neutral gas. The dominant behaviour can be represented by a diffusion equation containing an effective diffusion constant which depends upon pressure and dimensions of the enclosure. In the limit of large pressure and large enclosure the usual expression of the diffusion constant is obtained. The approach to this limit dePends upon the electron-neutral interaction. The effect of various model and measured cross sections for some inert gases is discussed.

Australian Journal of Physics, 1974

Baxter's method of solving the eight-vertex model in lattice statistical mechanics is examine... more Baxter's method of solving the eight-vertex model in lattice statistical mechanics is examined from an elementary point of view. It is shown that the algebraic operations in the method can be carried out without recourse to elliptic functions. These include: construction of certain subspaces invariant uti.der the action of the transfer matrix; reduction of the transfer matrix eigenvalue problem to an equivalent ice-type problem and construction of certain matrices which commute with the transfer matrix and satisfy a functional matrix equation.

Nuclear Physics, 1958

The contribution of the strong hyperon-K-meson-nucleon interaction to the nucleon magnetic moment... more The contribution of the strong hyperon-K-meson-nucleon interaction to the nucleon magnetic moment has been calculated, to the first order. In order to fit. the observed values with pseudoscalar K-mesons one needs gars/4x _ 9.6 and gxNY2 /gpr 2 = 0.06. If, however, the K-meson is assumed to be scalar, the last ratio becomes 0.016, which is perhaps too small, and g~re!4n in this case is 11 .3 .

Physical Review, 1956

Certain symmetry arguments have been used to suggest that the beta-decay interaction is S-T+P. It... more Certain symmetry arguments have been used to suggest that the beta-decay interaction is S-T+P. It is shown that if the negative electron in these arguments is replaced by the positron, the result is S+T+P and that the proposed symmetries do not lead to Hermitian Hamiltonians which treat negatrons and positrons on the same footing.

Physical Review, 1957

The methods of calculating the energy levels in spheroidal nuclei are discussed. It is shown that... more The methods of calculating the energy levels in spheroidal nuclei are discussed. It is shown that the expansion of the perturbation in powers of the deformation parameter, beta, leads to a very slowly convergent series representation of the matrix elements. An alternative method of expressing the perturbation, due to Moszkowski, which can allow a better calculation, is also discussed.

Swarm Studies and Inelastic Electron-Molecule Collisions, 1987

The effect of boundaries and finite enclosures on swarms has been the subject of a number of stud... more The effect of boundaries and finite enclosures on swarms has been the subject of a number of studies. We recall the work on electrons from a steady source incident on a planeabsorbing boundary [1], on diffusion cooling of electrons in finite enclosures [2], on attachment cooling [3] and on pressure dependence of mobility of ions (or runaway ions)[4]. The study of retarding potential difference analysis of the ion distribution function [5], and the considerations presented in the preceding talk by Tagashira [6], are also related to such effects.

The Journal of Infection in Developing Countries, 2013

Introduction: It is important to identify Salmonella Typhi infection quickly to treat acute fever... more Introduction: It is important to identify Salmonella Typhi infection quickly to treat acute fever patients and to prevent transmission by chronic typhoid carriers; therefore, a very specific and sensitive diagnostic technique is highly desirable, especially in endemic areas. The objective of this study was to develop a PCR protocol targeting the putative fimbrial staA gene of S. Typhi. This is a preferred target gene that is specifically amplified in the S. Typhi serotype compared to the commonly targeted fliC gene which may also be amplified from the non-typhoidal Salmonella Munchen serotype. Methodology: A new nested PCR primer methodology was designed to target the staA gene, which is a member of the fimbrial gene family specific to Salmonella Typhi only. Results: The primers were found to be very specific as the desired amplicon (377 bp) could be generated exclusively from S. Typhi strains including the reference strain (MTCC 3216) and 78 clinical isolates . Restriction digestio...

Nuclear Physics, 1963

A generalised Fermi-Thomas method, in which Kmatrices are used to obtain ; the potential energy, ... more A generalised Fermi-Thomas method, in which Kmatrices are used to obtain ; the potential energy, is used to calculate the energies and density distributions ; of nuclei for all mass values. It is shown that satisfactory agreement with the ; known empirical values, neglecting small shell effects, can be obtained but the ; corresponding Kmatrices will differ from those given

Nuclear Physics, 1964

Abstract The approximations involved in obtaining a Fermi-Thomas type of theory for nuclei are he... more Abstract The approximations involved in obtaining a Fermi-Thomas type of theory for nuclei are here related to the structure of the single-particle density matrix. Cases of both uniform and varying density are discussed.

Physical Review, 1961

The Hartree-Fock to Fermi-Thomas reduction is carried through for finite nuclei, starting with th... more The Hartree-Fock to Fermi-Thomas reduction is carried through for finite nuclei, starting with the iT-matrix formulation. The resulting expression represents the nuclear energy to good accuracy in terms of the density and its first derivatives only; it differs in detail from the semiempirical expressions previously proposed for this purpose. This improved expression shows the inadequacy of the "semi-infinite" approximation used often in earlier studies.

Vacuum, 1967

232 235 (f) Completion of the second approximation: Navier-Stokes equations 235 (g) General schem... more 232 235 (f) Completion of the second approximation: Navier-Stokes equations 235 (g) General scheme of the Chapman-Enskog method 236

Journal of the Physical Society of Japan, 1995

The basic formulation of the flight-time-integral method of Ikuta and coworkers is examined from ... more The basic formulation of the flight-time-integral method of Ikuta and coworkers is examined from a physical point of view. It is shown that if all equivalent flights are treated on an equal footing some corrections are needed. The content of the method then becomes the same as that of the path-integral method and therefore connection can also be made with the gradient expansion method. The expression for the drift velocity obtained in the flight-time-integral method is in agreement with that obtained from other methods and after some correction the expression for the diffusion coefficient can also be made to agree.