We show analytically that there exists a nonlinear (U-shaped) relationship between credit spreads... more We show analytically that there exists a nonlinear (U-shaped) relationship between credit spreads and the liquidity of the market for a firm's real assets. We empirically verify that indeed there is an interior optimum level of market liquidity at which credit spreads are at their lowest. Our results are particularly pronounced for highly leveraged firms and firms with large growth options. We further find that cash holdings affect the influence of real asset liquidity on credit spreads. However, this interaction between cash holdings and real asset liquidity is only significant in circumstances in which real asset liquidity is high.
Sustainability Accounting, Management and Policy Journal, 2021
Purpose The purpose of this study is to examine whether the choice of a firm to spend resources o... more Purpose The purpose of this study is to examine whether the choice of a firm to spend resources on corporate social responsibility (CSR) activities is associated with its actual social impacts as measured by its energy consumption and the quality of its financial reporting. Based on legitimacy theory, the authors argue firms in India use CSR expenditures as mere smoke screens to build a positive public image. Design/methodology/approach By using energy consumption per unit of sale as a measure of real environmental impact, the authors model firms' CSR investment behavior. Additionally, the authors use earnings management measures to examine whether CSR spenders engage in manipulating reported earnings, a practice socially responsible firms would not engage in. These hypotheses are tested using a panel data set of Indian firms for the period 2012–2014. Findings Consistent with legitimacy theory, the authors show firms that participate in socially undesirable activities such as he...
Journal of the Nigerian Association of Mathematical Physics, 2009
Here, we use our new metric tensor exterior to a massiv3e oblate spheroid to study the gravitatio... more Here, we use our new metric tensor exterior to a massiv3e oblate spheroid to study the gravitational phenomena of time dilation and length contraction. It turns out most profoundly that, the above phenomena hold good in the gravitational field exterior to an oblate spheroid. We then use the oblate spheroidal Earth to exemplify our findings in approximate gravitational fields. Journal of the Nigerian Association of Mathematical Physics , Volume 15 (November, 2009), pp 247 - 252
This dissertation examines the relationship between the ability of a firm to sell its real assets... more This dissertation examines the relationship between the ability of a firm to sell its real assets (asset liquidity) and its cash holdings behavior as well as its cost of debt. In essay 1, I show that for financially constrained firms there exists a negative relationship between the liquidity of a firm’s real assets and the size of its cash holdings, however no such relationship is present for financially unconstrained firms. This indicates a substitution effect between cash balances and liquid real assets when access to external capital markets is limited. Additionally, I find that among financial constrained firms the market value of cash holdings is lower among firms possessing more liquid real assets. In essay 2, I examine the implications of this cash holdings/asset liquidity relationship on the cost of corporate debt. First, I develop a simple two period model of credit spreads endogenizing the cash holdings/asset liquidity trade-off and show that there exists a non-linear (U-s...
Here, we use our new metric tensor exterior to homogeneous oblate spheroidal mass distributions t... more Here, we use our new metric tensor exterior to homogeneous oblate spheroidal mass distributions to study gravitational spectral shift of light in the vicinity of the Sun, Earth and other oblate spheroidal planets. It turns out most profoundly that, this experimentally verified phenomenon holds good in the gravitational field exterior to an oblate spheroid using our approach. In approximate gravitational fields, our obtained theoretical value for the Pound-Rebka experiment on gravitational spectra shift along the equator of the Earth (2.578×10−15) agrees satisfactorily with the experimental value of 2.45×10−15. We also predict theoretical values for the Pound-Rebka experiment on the surface (along the equator) of the Sun and other oblate spheroidal planets.
We describe a laboratory experiment in which the local acceleration of gravity, g, was determined... more We describe a laboratory experiment in which the local acceleration of gravity, g, was determined. This work is primarily one utility of a theory for conversion of mechanical energy into electrical energy. It involves measurement of impact time between two metallic bodies. The setup consists of a thin copper wire suspending a pendulum metal bob. The wire was passed over into connection with a chosen resistor in series with an electrolytic capacitor. The latter connected to a larger metallic body. At a determined height, the bob was allowed to make an impact with the larger metallic body to induce an electric current of which voltage was recorded by means of a voltmeter connected across the electrolytic capacitor. Errors due to oscillations in the conventional pendulum experiment were avoided because only one impact was allowed for every set of readings. Interesting common analyses were found sufficient for calculations of standard errors on g . Keywords: Didactic, local acceleration...
The low-income member countries of the Organization of the Islamic Conference (OIC-LDCs) receive ... more The low-income member countries of the Organization of the Islamic Conference (OIC-LDCs) receive substantial amount of official development assistant (ODA) purposely to improve economic condition which is characteristically and persistently poor. 23 OIC-LDCs, being common ODA recipients were, selected over period 1960-2007. This paper investigate the effect ODA, oil-price increase and conflict on OIC-LDCs’ economic growth employing Fixed Effect Error Component (FEEC) technique. We found that little interrelationship exist between OIC-recipient countries’ GDP and ODA, which is consistent with Burnside and Dollar (2000, 2004) findings. The civil armed conflict is negatively related with GDP growth. We also found that a shock effect of $10 increase in price of crude oil per barrel, on average, will reduce oil-importing OIC member countries’ economic growth by 0.3%.
In This work, the Maxwell's equations were used to obtain a transverse wave equation. A trial sol... more In This work, the Maxwell's equations were used to obtain a transverse wave equation. A trial solution of the wave equation that has both the amplitude and the field distribution function of the terahertz (THz) radiation were used to generate a dimensionless nonlinear Schrödinger equation (NLSE) for the fourth order harmonics. The numerical simulation of the NLSE for the THz radiation was tested on a fiberlike nonlinear uniaxial crystal based on three parameters. The nonlinear coefficient, the dimensionless pulsewidth, and the order of the solitary wave. The dynamic pulse profiles show that THz could have an application in optical communications, just like Laser in optical fiber communication.
*This work is an attempt to elucidate benefits assoc iated with higher order nonlinear Schrodinge... more *This work is an attempt to elucidate benefits assoc iated with higher order nonlinear Schrodinger equat ions (NLSE’s) as compared with to the cubic nonlinear Schrodinger eq uation (CNLSE). The higher order nonlinear Schrodinger equations are: (1) the cubic quintic nonlinear Schrodinger equatio n, (CQNLSE); (2) the single saturable nonlinear Schr odinger equation (SSNLSE); (3) the double saturable nonlinear Schrodinger equation (DSNLSE); and (4) the coupled cubic quintic nonlinear Schrodinger equations (CCQNLSE’s). Before now, a few of merits of the higher order NLSE’s were tacitly mi sunderstood and thus partially explained. Consequently, a state of vagueness has been, for long, making it impossi ble to enable considerations and utilities for scientific and tec hnological applications. The NLSE’s considered are used to describe physics of pulses in variety of mono-mode optical fibres. T hese pulses are termed solitary waves or solitons o f which concepts are thoroughly explained. The generalized NLSE’s and their methods of solutions are also reviewed. Novel c lear tabulation of data is given for physical implications that make t he higher order NLSE’s necessary. In addition, resu lts of a variational method (VM) of solutions applied to the SSNLSE are presented in contradistinction to the results for CQ NLSE for the same VM. Moreover, this article has been intentionally p repared to serve as a dependable resource to guide researchers in the fields of nonlinear optics applicable to optical me dia.
The mechanics of star interiors has remained a subject of much research concern. Many theories ha... more The mechanics of star interiors has remained a subject of much research concern. Many theories have been proposed to account for the behavior of stars. However, these theories have one shortcoming or the other. A star model based on general relativity theory and current astrophysical observations was recently proposed. High gravitational forces, mass concentration in cores, rapid rates of spin and high centripetal forces gives stars their spheroidal shapes. In this article, the gravitational metric tensor of a spherically symmetric sphere containing a non compressible liquid is extended to formulate an oblate spheroidal plasma star model. Using removable space singularities at the Hilbert radius and in outer space, the plasma stars are classified into three major groups (regular, neutron stars and pulsars, black holes). The metric tensor for an oblate spheroidal liquid star obtained has six non zero components as opposed to four for spherical plasma star model.
The mechanics of star interiors has remained a subject of much research concern. Many theories ha... more The mechanics of star interiors has remained a subject of much research concern. Many theories have been proposed to account for the behavior of stars. However, these theories have one shortcoming or the other. A star model based on general relativity theory and current astrophysical observations was recently proposed. High gravitational forces, mass concentration in cores, rapid rates of spin and high centripetal forces gives stars their spheroidal shapes. In this article, the gravitational metric tensor of a spherically symmetric sphere containing a non compressible liquid is extended to formulate an oblate spheroidal plasma star model. Using removable space singularities at the Hilbert radius and in outer space, the plasma stars are classified into three major groups (regular, neutron stars and pulsars, black holes). The metric tensor for an oblate spheroidal liquid star obtained has six non zero components as opposed to four for spherical plasma star model.
Journal of the Nigerian Association of Mathematical Physics, 2011
We investigate the question over the nature of the left and right derivatives of Moufang loops an... more We investigate the question over the nature of the left and right derivatives of Moufang loops and find out that the derivatives of a Moufang loop are Moufang loops that is, loops of Bol-Moufang type. Keywords: Derivatives, Moufang loops, Isotopism, Principal isotopism, k-isotope Journal of the Nigerian Association of Mathematical Physics , Volume 19 (November, 2011), pp 33 – 36
Ecotourism is regarded as an ideal mechanism for achieving both economic and ecological sustainab... more Ecotourism is regarded as an ideal mechanism for achieving both economic and ecological sustainability. The objective of this study is to determine the tourists' willingness to pay for conservation in Yankari game reserve using a dichotomous choice contingent valuation method (DC-CVM) on 335 local tourists. The result of the study showed that the mean willingness to pay as entrance fee by a tourist is 508 Naira (USD 3.4). The findings of this study would provide a guide to the management of the game reserve to take into account the benefits associated with resources conservation and the need to review their pricing policy.
In this article, we extend the metric tensor exterior to astrophysically real or imaginary spheri... more In this article, we extend the metric tensor exterior to astrophysically real or imaginary spherical distributions of mass whose tensor field varies with polar angle only; to derive equations of motion for test particles in this field. The time, radial, polar and azimuthal equations of motion for particles of non-zero rest masses moving in this gravitational field have been derived. The expression for the variation of the time on a clock moving in this gravitational field has been obtained for pure radial motion, the particles move with a constant velocity.
Phase transitions in a recently discovered class of hydrogen-bonded organic crystals are analyzed... more Phase transitions in a recently discovered class of hydrogen-bonded organic crystals are analyzed by Landau theory. It is shown that the transitions are ferroelastic. Two types of transition, orthorhombic-to-monoclinic and monoclinic-to-triclinic, are analysed using an expansion of the free energy in symmetry-allowed powers of the strain components. For three examples, new data are presented for the crystallographic parameters in a range of temperature including the phase transition point T c : These data show that the transitions are second order and the temperature dependences are consistent with the mean-field analysis. We propose that the making and breaking of the hydrogen bond interactions with variation of temperature accounts for these reversible ferroelastic phase transitions. Expressions are derived for the entropy and the specific-heat discontinuity at T c : It is pointed out that the transitions should be accompanied by 'soft-mode' behavior in a phonon of appropriate symmetry.
Journal of Physics A: Mathematical and General, 1998
Solitary wave solutions are determined analytically for two forms of nonlinear Schrödinger equati... more Solitary wave solutions are determined analytically for two forms of nonlinear Schrödinger equations with saturation effects in the denominators of their nonlinearity terms. Pertinent parameters, being explicitly stated, make the results applicable to soliton phenomena.
Journal of Nonlinear Optical Physics & Materials, 1998
With a variational method, we study the cubic-quintic nonlinear Schrödinger equation for pulse pr... more With a variational method, we study the cubic-quintic nonlinear Schrödinger equation for pulse propagation in optical fibers. Anomalous dispersion that gives rise to fundamental bright solitary waves is considered. It is shown that within the specified limits, the present variational model demonstrates (for 1 picosecond pulse) good agreements with its analytical equivalent. It is proved that for negative coefficient of the fifth-order nonlinearity existence of the two-state solitary wave solution is a peculiarity of the variational formulation.
Birefringence is a phenomenon that produces doublevalue nature of refractive indices in uniaxial ... more Birefringence is a phenomenon that produces doublevalue nature of refractive indices in uniaxial crystals. This phenomenon gives rise to effects such as ordinary (o) and extraordinary waves (e) and Kerr effect which produces nonlinear coefficients called Kerr constants. In this work, twelve uniaxial crystals are considered. The minimum electric field intensity that is required to produce nonlinear birefringence is determined. The magnitudes of the nonvanishing dielectric tensor components and their corresponding critical angles have been evaluated for the twelve uniaxial crystals. The result shows that in negative uniaxial crystals, electromagnetic waves travel faster in the extraordinary axis than in the ordinary axes. The reverse is however obtained in positive uniaxial axis. The work has also provided the series to be employed when determining the Kerr constants for even order nonlinear coefficients. A motivation for this work is an attempt to make nonlinear optical phenomena accessible to physics undergraduate.
Resumen: Detailed discussions are presented on the determination of Planck's constant from t... more Resumen: Detailed discussions are presented on the determination of Planck's constant from the Planck radiation law. The laboratory setup consists of a low cost lamp and a photodiode such that a light filter of known wavelength is interposed between the two ...
We show analytically that there exists a nonlinear (U-shaped) relationship between credit spreads... more We show analytically that there exists a nonlinear (U-shaped) relationship between credit spreads and the liquidity of the market for a firm's real assets. We empirically verify that indeed there is an interior optimum level of market liquidity at which credit spreads are at their lowest. Our results are particularly pronounced for highly leveraged firms and firms with large growth options. We further find that cash holdings affect the influence of real asset liquidity on credit spreads. However, this interaction between cash holdings and real asset liquidity is only significant in circumstances in which real asset liquidity is high.
Sustainability Accounting, Management and Policy Journal, 2021
Purpose The purpose of this study is to examine whether the choice of a firm to spend resources o... more Purpose The purpose of this study is to examine whether the choice of a firm to spend resources on corporate social responsibility (CSR) activities is associated with its actual social impacts as measured by its energy consumption and the quality of its financial reporting. Based on legitimacy theory, the authors argue firms in India use CSR expenditures as mere smoke screens to build a positive public image. Design/methodology/approach By using energy consumption per unit of sale as a measure of real environmental impact, the authors model firms' CSR investment behavior. Additionally, the authors use earnings management measures to examine whether CSR spenders engage in manipulating reported earnings, a practice socially responsible firms would not engage in. These hypotheses are tested using a panel data set of Indian firms for the period 2012–2014. Findings Consistent with legitimacy theory, the authors show firms that participate in socially undesirable activities such as he...
Journal of the Nigerian Association of Mathematical Physics, 2009
Here, we use our new metric tensor exterior to a massiv3e oblate spheroid to study the gravitatio... more Here, we use our new metric tensor exterior to a massiv3e oblate spheroid to study the gravitational phenomena of time dilation and length contraction. It turns out most profoundly that, the above phenomena hold good in the gravitational field exterior to an oblate spheroid. We then use the oblate spheroidal Earth to exemplify our findings in approximate gravitational fields. Journal of the Nigerian Association of Mathematical Physics , Volume 15 (November, 2009), pp 247 - 252
This dissertation examines the relationship between the ability of a firm to sell its real assets... more This dissertation examines the relationship between the ability of a firm to sell its real assets (asset liquidity) and its cash holdings behavior as well as its cost of debt. In essay 1, I show that for financially constrained firms there exists a negative relationship between the liquidity of a firm’s real assets and the size of its cash holdings, however no such relationship is present for financially unconstrained firms. This indicates a substitution effect between cash balances and liquid real assets when access to external capital markets is limited. Additionally, I find that among financial constrained firms the market value of cash holdings is lower among firms possessing more liquid real assets. In essay 2, I examine the implications of this cash holdings/asset liquidity relationship on the cost of corporate debt. First, I develop a simple two period model of credit spreads endogenizing the cash holdings/asset liquidity trade-off and show that there exists a non-linear (U-s...
Here, we use our new metric tensor exterior to homogeneous oblate spheroidal mass distributions t... more Here, we use our new metric tensor exterior to homogeneous oblate spheroidal mass distributions to study gravitational spectral shift of light in the vicinity of the Sun, Earth and other oblate spheroidal planets. It turns out most profoundly that, this experimentally verified phenomenon holds good in the gravitational field exterior to an oblate spheroid using our approach. In approximate gravitational fields, our obtained theoretical value for the Pound-Rebka experiment on gravitational spectra shift along the equator of the Earth (2.578×10−15) agrees satisfactorily with the experimental value of 2.45×10−15. We also predict theoretical values for the Pound-Rebka experiment on the surface (along the equator) of the Sun and other oblate spheroidal planets.
We describe a laboratory experiment in which the local acceleration of gravity, g, was determined... more We describe a laboratory experiment in which the local acceleration of gravity, g, was determined. This work is primarily one utility of a theory for conversion of mechanical energy into electrical energy. It involves measurement of impact time between two metallic bodies. The setup consists of a thin copper wire suspending a pendulum metal bob. The wire was passed over into connection with a chosen resistor in series with an electrolytic capacitor. The latter connected to a larger metallic body. At a determined height, the bob was allowed to make an impact with the larger metallic body to induce an electric current of which voltage was recorded by means of a voltmeter connected across the electrolytic capacitor. Errors due to oscillations in the conventional pendulum experiment were avoided because only one impact was allowed for every set of readings. Interesting common analyses were found sufficient for calculations of standard errors on g . Keywords: Didactic, local acceleration...
The low-income member countries of the Organization of the Islamic Conference (OIC-LDCs) receive ... more The low-income member countries of the Organization of the Islamic Conference (OIC-LDCs) receive substantial amount of official development assistant (ODA) purposely to improve economic condition which is characteristically and persistently poor. 23 OIC-LDCs, being common ODA recipients were, selected over period 1960-2007. This paper investigate the effect ODA, oil-price increase and conflict on OIC-LDCs’ economic growth employing Fixed Effect Error Component (FEEC) technique. We found that little interrelationship exist between OIC-recipient countries’ GDP and ODA, which is consistent with Burnside and Dollar (2000, 2004) findings. The civil armed conflict is negatively related with GDP growth. We also found that a shock effect of $10 increase in price of crude oil per barrel, on average, will reduce oil-importing OIC member countries’ economic growth by 0.3%.
In This work, the Maxwell's equations were used to obtain a transverse wave equation. A trial sol... more In This work, the Maxwell's equations were used to obtain a transverse wave equation. A trial solution of the wave equation that has both the amplitude and the field distribution function of the terahertz (THz) radiation were used to generate a dimensionless nonlinear Schrödinger equation (NLSE) for the fourth order harmonics. The numerical simulation of the NLSE for the THz radiation was tested on a fiberlike nonlinear uniaxial crystal based on three parameters. The nonlinear coefficient, the dimensionless pulsewidth, and the order of the solitary wave. The dynamic pulse profiles show that THz could have an application in optical communications, just like Laser in optical fiber communication.
*This work is an attempt to elucidate benefits assoc iated with higher order nonlinear Schrodinge... more *This work is an attempt to elucidate benefits assoc iated with higher order nonlinear Schrodinger equat ions (NLSE’s) as compared with to the cubic nonlinear Schrodinger eq uation (CNLSE). The higher order nonlinear Schrodinger equations are: (1) the cubic quintic nonlinear Schrodinger equatio n, (CQNLSE); (2) the single saturable nonlinear Schr odinger equation (SSNLSE); (3) the double saturable nonlinear Schrodinger equation (DSNLSE); and (4) the coupled cubic quintic nonlinear Schrodinger equations (CCQNLSE’s). Before now, a few of merits of the higher order NLSE’s were tacitly mi sunderstood and thus partially explained. Consequently, a state of vagueness has been, for long, making it impossi ble to enable considerations and utilities for scientific and tec hnological applications. The NLSE’s considered are used to describe physics of pulses in variety of mono-mode optical fibres. T hese pulses are termed solitary waves or solitons o f which concepts are thoroughly explained. The generalized NLSE’s and their methods of solutions are also reviewed. Novel c lear tabulation of data is given for physical implications that make t he higher order NLSE’s necessary. In addition, resu lts of a variational method (VM) of solutions applied to the SSNLSE are presented in contradistinction to the results for CQ NLSE for the same VM. Moreover, this article has been intentionally p repared to serve as a dependable resource to guide researchers in the fields of nonlinear optics applicable to optical me dia.
The mechanics of star interiors has remained a subject of much research concern. Many theories ha... more The mechanics of star interiors has remained a subject of much research concern. Many theories have been proposed to account for the behavior of stars. However, these theories have one shortcoming or the other. A star model based on general relativity theory and current astrophysical observations was recently proposed. High gravitational forces, mass concentration in cores, rapid rates of spin and high centripetal forces gives stars their spheroidal shapes. In this article, the gravitational metric tensor of a spherically symmetric sphere containing a non compressible liquid is extended to formulate an oblate spheroidal plasma star model. Using removable space singularities at the Hilbert radius and in outer space, the plasma stars are classified into three major groups (regular, neutron stars and pulsars, black holes). The metric tensor for an oblate spheroidal liquid star obtained has six non zero components as opposed to four for spherical plasma star model.
The mechanics of star interiors has remained a subject of much research concern. Many theories ha... more The mechanics of star interiors has remained a subject of much research concern. Many theories have been proposed to account for the behavior of stars. However, these theories have one shortcoming or the other. A star model based on general relativity theory and current astrophysical observations was recently proposed. High gravitational forces, mass concentration in cores, rapid rates of spin and high centripetal forces gives stars their spheroidal shapes. In this article, the gravitational metric tensor of a spherically symmetric sphere containing a non compressible liquid is extended to formulate an oblate spheroidal plasma star model. Using removable space singularities at the Hilbert radius and in outer space, the plasma stars are classified into three major groups (regular, neutron stars and pulsars, black holes). The metric tensor for an oblate spheroidal liquid star obtained has six non zero components as opposed to four for spherical plasma star model.
Journal of the Nigerian Association of Mathematical Physics, 2011
We investigate the question over the nature of the left and right derivatives of Moufang loops an... more We investigate the question over the nature of the left and right derivatives of Moufang loops and find out that the derivatives of a Moufang loop are Moufang loops that is, loops of Bol-Moufang type. Keywords: Derivatives, Moufang loops, Isotopism, Principal isotopism, k-isotope Journal of the Nigerian Association of Mathematical Physics , Volume 19 (November, 2011), pp 33 – 36
Ecotourism is regarded as an ideal mechanism for achieving both economic and ecological sustainab... more Ecotourism is regarded as an ideal mechanism for achieving both economic and ecological sustainability. The objective of this study is to determine the tourists' willingness to pay for conservation in Yankari game reserve using a dichotomous choice contingent valuation method (DC-CVM) on 335 local tourists. The result of the study showed that the mean willingness to pay as entrance fee by a tourist is 508 Naira (USD 3.4). The findings of this study would provide a guide to the management of the game reserve to take into account the benefits associated with resources conservation and the need to review their pricing policy.
In this article, we extend the metric tensor exterior to astrophysically real or imaginary spheri... more In this article, we extend the metric tensor exterior to astrophysically real or imaginary spherical distributions of mass whose tensor field varies with polar angle only; to derive equations of motion for test particles in this field. The time, radial, polar and azimuthal equations of motion for particles of non-zero rest masses moving in this gravitational field have been derived. The expression for the variation of the time on a clock moving in this gravitational field has been obtained for pure radial motion, the particles move with a constant velocity.
Phase transitions in a recently discovered class of hydrogen-bonded organic crystals are analyzed... more Phase transitions in a recently discovered class of hydrogen-bonded organic crystals are analyzed by Landau theory. It is shown that the transitions are ferroelastic. Two types of transition, orthorhombic-to-monoclinic and monoclinic-to-triclinic, are analysed using an expansion of the free energy in symmetry-allowed powers of the strain components. For three examples, new data are presented for the crystallographic parameters in a range of temperature including the phase transition point T c : These data show that the transitions are second order and the temperature dependences are consistent with the mean-field analysis. We propose that the making and breaking of the hydrogen bond interactions with variation of temperature accounts for these reversible ferroelastic phase transitions. Expressions are derived for the entropy and the specific-heat discontinuity at T c : It is pointed out that the transitions should be accompanied by 'soft-mode' behavior in a phonon of appropriate symmetry.
Journal of Physics A: Mathematical and General, 1998
Solitary wave solutions are determined analytically for two forms of nonlinear Schrödinger equati... more Solitary wave solutions are determined analytically for two forms of nonlinear Schrödinger equations with saturation effects in the denominators of their nonlinearity terms. Pertinent parameters, being explicitly stated, make the results applicable to soliton phenomena.
Journal of Nonlinear Optical Physics & Materials, 1998
With a variational method, we study the cubic-quintic nonlinear Schrödinger equation for pulse pr... more With a variational method, we study the cubic-quintic nonlinear Schrödinger equation for pulse propagation in optical fibers. Anomalous dispersion that gives rise to fundamental bright solitary waves is considered. It is shown that within the specified limits, the present variational model demonstrates (for 1 picosecond pulse) good agreements with its analytical equivalent. It is proved that for negative coefficient of the fifth-order nonlinearity existence of the two-state solitary wave solution is a peculiarity of the variational formulation.
Birefringence is a phenomenon that produces doublevalue nature of refractive indices in uniaxial ... more Birefringence is a phenomenon that produces doublevalue nature of refractive indices in uniaxial crystals. This phenomenon gives rise to effects such as ordinary (o) and extraordinary waves (e) and Kerr effect which produces nonlinear coefficients called Kerr constants. In this work, twelve uniaxial crystals are considered. The minimum electric field intensity that is required to produce nonlinear birefringence is determined. The magnitudes of the nonvanishing dielectric tensor components and their corresponding critical angles have been evaluated for the twelve uniaxial crystals. The result shows that in negative uniaxial crystals, electromagnetic waves travel faster in the extraordinary axis than in the ordinary axes. The reverse is however obtained in positive uniaxial axis. The work has also provided the series to be employed when determining the Kerr constants for even order nonlinear coefficients. A motivation for this work is an attempt to make nonlinear optical phenomena accessible to physics undergraduate.
Resumen: Detailed discussions are presented on the determination of Planck's constant from t... more Resumen: Detailed discussions are presented on the determination of Planck's constant from the Planck radiation law. The laboratory setup consists of a low cost lamp and a photodiode such that a light filter of known wavelength is interposed between the two ...
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