Krzysztof Rębilas - Academia.edu (original) (raw)
Papers by Krzysztof Rębilas
Foundations of Physics Letters, 2006
The quantities E and B are then manifestly interdependent. We prove that they are determined by M... more The quantities E and B are then manifestly interdependent. We prove that they are determined by Maxwell's equations, so they represent the electric and magnetic fields in the new frame and the force F is the well known from experiments Lorentz force. In this way Maxwell's equations may be discovered theoretically for this particular situation of uniformly moving sources. The general solutions of the discovered Maxwell's equations lead us to fields produced by accelerating sources.
Emergence of one-time-direction macroscopic evolution of a classical system of two mixed gases ha... more Emergence of one-time-direction macroscopic evolution of a classical system of two mixed gases having different temperatures is derived and explained. The analysis performed at the microscopic level, where the time-symmetric laws of mechanics govern the particles collisions, leads to a time-asymmetric macroscopic heat transfer equation and a theorem analogous to the Boltzmann H-theorem. Some statistical symmetries in the velocity distribution that should be satisfied by the incoming and outgoing particles are pointed out. The time reversed evolution is shown to be highly improbable because in this case these typical symmetries are broken. Additionally, some remarks explaining implicit time-asymmetry of the Boltzmann Stosszahlansatz are made.
We present the first study of light induced atom desorption (LIAD) of an alkali atom (Rb) in poro... more We present the first study of light induced atom desorption (LIAD) of an alkali atom (Rb) in porous alumina. We observe the variation due to LIAD of the rubidium density in a vapor cell as a function of illumination time, intensity and wavelength. The simple and regular structure of the alumina pores allows a description of the atomic diffusion in the porous medium in which the diffusion constant only depends on the known pore geometry and the atomic sticking time to the pore wall. A simple one-dimensional theoretical model is presented which reproduces the essential features of the observed signals. Fitting of the model to the experimental data gives access to the diffusion constant and consequently the atom-wall sticking time and its dependence on light intensity and wavelength. The non-monotonic dependence of the LIAD yield on the illumination light frequency is indicative of the existence of Rb clusters in the porous medium.
Acta Physica Polonica A, 2021
The phenomenon of static friction is demonstrated in some challenging situations. The work-energy... more The phenomenon of static friction is demonstrated in some challenging situations. The work-energy theorem and the center-mass equation are elucidated and clearly discerned when used and interpreted in problems with static friction. Especially, it is demonstrated that it is indispensable to refer to thermodynamics to provide a complete and adequate description of some seemingly purely mechanical problems with static friction involved. The static frictional force, although being a zero-work force, is proved to influence energy acquired by a system. Unexpected values and directions of the static frictional forces are shown for some specific cases. Finally, it is explained how static friction plays a crucial role in the working of a store security tag, a device commonly used at clothes shops to prevent theft.
American Journal of Physics, 2010
Besides the well known scalar invariants, there exist also vectorial invariants in the realm of s... more Besides the well known scalar invariants, there exist also vectorial invariants in the realm of special relativity. It is shown that the three-vector d p dt v +γ v d p dt ⊥v is invariant under the Lorentz transformation. The indices v and ⊥v denote the respective components established with respect to the direction of the velocity of body v, and p is the relativistic momentum. We prove that this vector is equal to a force of F R satisfying the classical Newtonian law F R = m a R in the instantaneous inertial rest frame of an accelerated body. Therefore the equation F R = d p dt v + γ v d p dt ⊥v , based on the Lorentz-invariant vectors, may be used as a truly invariant (not merely a covariant) relativistic equation of motion in any inertial system of reference. An alternative approach to classical electrodynamics based on the invariant three-vectors is proposed.
Polimery, 2008
Formation of surface and inclusion complexes of single-walled carbon nanotubes (SWCNT) with dextr... more Formation of surface and inclusion complexes of single-walled carbon nanotubes (SWCNT) with dextrans of M w 6000 to 2 000 000 was proven spectrally, rheologically, and calorimetrically. Band shifts in the Raman spectra, increase in the viscosity of aqueous ...
International Agrophysics
The aim of the study was to describe the distribution of pea root mass in the soil, over a three-... more The aim of the study was to describe the distribution of pea root mass in the soil, over a three-year period, under varying weather conditions and at different levels of phosphorus application, by means of evaluating and comparing parameters of a mathematical model characterising cumulative root mass distribution. A two-factor experiment was conducted in Prusy, near Krakow: the first factor was the level of phosphorus application (0-70-140 kg P2O5 ha−1) and the second was the cultivars (six cultivars were tested). Experimental data produced using the model indicated that the root distribution was strongly differentiated by water availability in the years of the study. This appeared in some cases to be a more important factor than phosphorus application rates. The estimated soil depth at which 50% of the root mass was accumulated differed significantly for the dry and the wet year. In the wet year, only very high phosphorus application rates contributed to an increase in root mass di...
Starting from the classical Newton's second law which, according to our assumption, is valid ... more Starting from the classical Newton's second law which, according to our assumption, is valid in any instantaneous inertial rest frame of body that moves in Minkowskian space-time we get the relativistic equation of motion vecF=dvecp/dt\vec{F}=d\vec{p}/dtvecF=dvecp/dt, where vecp\vec{p}vecp is the relativistic momentum. The relativistic momentum is then derived without referring to any additional assumptions concerning elastic collisions of bodies. Lorentz-invariance of the relativistic law is proved without tensor formalism. Some new method of force transformation is also presented.
American Journal of Physics, 2015
ABSTRACT The spin of a gyroscope that undergoes Thomas precession seems to change its direction w... more ABSTRACT The spin of a gyroscope that undergoes Thomas precession seems to change its direction without any torque, which would mean that conservation of angular momentum is violated. To resolve this paradox, it is shown that the spin dynamics equation describing Thomas precession (the BMT equation) can be written in terms of a torque applied to the spin. A simple method of finding an explicit expression for the torque is presented in the case of a gyroscope performing circular motion. An unexpected oscillatory character of the torque is explained in terms of the difference between the proper spin and the spin observed in the laboratory frame.
The Physics Teacher, 2013
ABSTRACT Consider a skier who goes down a takeoff ramp, attains a speed V, and jumps, attempting ... more ABSTRACT Consider a skier who goes down a takeoff ramp, attains a speed V, and jumps, attempting to land as far as possible down the hill below (Fig. 1). At the moment of takeoff the angle between the skier's velocity and the horizontal is α. What is the optimal angle α that makes the jump the longest possible for the fixed magnitude of the velocity V? Of course, in practice, this is a very sophisticated problem; the skier's range depends on a variety of complex factors in addition to V and α. However, if we ignore these and assume the jumper is in free fall between the takeoff ramp and the landing point below, the problem becomes an exercise in kinematics that is suitable for introductory-level students. The solution is presented here.
Plant Cell, Tissue and Organ Culture, 2008
A theoretical model explaining the average DNA content in cells of in vitro cultures as a functio... more A theoretical model explaining the average DNA content in cells of in vitro cultures as a function of concentration of auxin 2,4-D in medium is provided. The model assumes influence of auxin on the functioning of the main G1/S and G2/M control points of the cell cycle. Theoretical results are compared to experimental data obtained from the callus cultures of Allium sativum and Allium cepa conducted during 18 months. Adaptation of the model to explanation of the shape of the doseresponse curves is suggested and successfully verified for the example of Nicotiana tabacum cultures. Keywords Auxin 2,4-D Á Cell cycle Á DNA content Á Dose response Á Theoretical model Abbreviations 2,4-D 2,4-Dichlorophenoxyacetic acid MS Murashige and Skoog (1962) medium NAA a-Naphthalene acetic acid TIR1 Transport inhibitor response protein 1 K. Rębilas (&)
Physical Review A, 2009
ABSTRACT The light-induced atomic desorption effect, known as LIAD, has been explained so far by ... more ABSTRACT The light-induced atomic desorption effect, known as LIAD, has been explained so far by a debatable Atutov’s theory [ S. N. Atutov et al. Phys. Rev. A 60 4693 (1999)]. In this Brief Report, we propose an approach in which the difficulties of this theory are removed. The theory yields predictions for the atomic vapor density n(t) in a fully illuminated resonance cell, the time tmax that it takes the vapor density to arrive at a maximum value nmax and the dependence of nmax and dn/dtt=+0 on the desorbing light intensity. Some of our results are at variance with outcomes of Atutov’s model (such as saturation effect for nmax and the dependence of tmax on the light intensity) but are in agreement with the experimental data. Additionally, the model presented in this Brief Report satisfactorily explains a reservoir effect recently investigated in experiments where cells equipped with a lockable stem were used.
Physical Review A, 2010
ABSTRACT In a recent article [Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.81.037801 81, 037801 (2... more ABSTRACT In a recent article [Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.81.037801 81, 037801 (2010)] a theory of light-induced atomic desorption for Rb in porous alumina is proposed. We point out that both the main assumption of this theory (the diffusion inside the pores treated as a random walk with the adsorption to the inner surface of the pores at any step) and several further hypotheses supporting the theoretical model require a revision.
Physical Review A, 2009
The commonly accepted theory of light-induced atomic desorption (LIAD) [S. N. Atutov , Phys. Rev.... more The commonly accepted theory of light-induced atomic desorption (LIAD) [S. N. Atutov , Phys. Rev. A 60, 4693 (1999)] explains the dynamics of this effect by referring to a light-enhanced diffusion process proceeding in the absorbing medium. On the other hand, recently performed measurements show that in siloxane films which are used in LIAD experiments, the characteristic time of diffusion is extremely short (a fraction of 1 s) compared to the duration of the LIAD effect (hundreds of seconds). This is in contradiction to the conceptual basis of the theory of Atutov that requires the characteristic diffusion time to be sufficiently long. What is more, the theory of Atutov relies on an unjustified assumption about the dependence of the diffusion coefficient on the light intensity. In consequence, the theoretical results of Atutov yield unsatisfactory predictions and do not fit well with experimental data. In this paper, we consider a partially illuminated siloxane-coated cell and propose an alternative theory of LIAD dynamics based on an assumption about lateral diffusion proceeding in the siloxane coating. Our theory provides a unique solution for the desorbed atoms' density regardless of the power of the laser light, explains the lengthy duration of LIAD, and accurately reproduces experimental results. A reasoning which explains how the boundary condition at the siloxane surface is established by the incident light gives us a proper relation between the desorbed atoms' density and the intensity of the desorbing light.
Foundations of Physics Letters, 2000
It is shown that Unnikrishnan's theory, which is believed to be a local realist theory resolving ... more It is shown that Unnikrishnan's theory, which is believed to be a local realist theory resolving the EPR puzzle, in two possible interpretations is either realist and nonlocal or local and non-realist.
Foundations of Physics, 2011
A direct method showing the Thomas precession for an evolution of any vector quantity (a spatial ... more A direct method showing the Thomas precession for an evolution of any vector quantity (a spatial part of a four-vector) is proposed. A useful application of this method is a possibility to trace correctly the presence of the Thomas precession in the Bargmann-Michel-Telegdi equation. It is pointed out that the Thomas precession is not incorporated in the kinematical term of the Bargmann-Michel-Telegdi equation, as it is commonly believed. When the Bargmann-Michel-Telegdi equation is interpreted in curved spacetimes, this term is shown to be equivalent to the affine connection term in the covariant derivative of the spin four-vector evolving in a gravitational field. It then contributes to the geodetic precession. The described problem is an interesting and unexpected example showing that approximate methods used in special relativity, in this case to identify the Thomas precession, can distort the true meaning of physical laws.
Food Hydrocolloids, 2006
Viscosity of aqueous solutions of dextrans of M w 19,500, 71,400, and 282,000 is fairly insensiti... more Viscosity of aqueous solutions of dextrans of M w 19,500, 71,400, and 282,000 is fairly insensitive to admixed L-arabinose, lactose, rhamnose, sorbitol, and xylitol. These results, together with results of polarimetric studies, suggested that a subtle increase in the viscosity of solutions, accompanied with increase in concentration of the additive was induced by changes in water activity rather than direct interactions between dextrans and additives.
Foundations of Physics Letters, 2006
The quantities E and B are then manifestly interdependent. We prove that they are determined by M... more The quantities E and B are then manifestly interdependent. We prove that they are determined by Maxwell's equations, so they represent the electric and magnetic fields in the new frame and the force F is the well known from experiments Lorentz force. In this way Maxwell's equations may be discovered theoretically for this particular situation of uniformly moving sources. The general solutions of the discovered Maxwell's equations lead us to fields produced by accelerating sources.
Emergence of one-time-direction macroscopic evolution of a classical system of two mixed gases ha... more Emergence of one-time-direction macroscopic evolution of a classical system of two mixed gases having different temperatures is derived and explained. The analysis performed at the microscopic level, where the time-symmetric laws of mechanics govern the particles collisions, leads to a time-asymmetric macroscopic heat transfer equation and a theorem analogous to the Boltzmann H-theorem. Some statistical symmetries in the velocity distribution that should be satisfied by the incoming and outgoing particles are pointed out. The time reversed evolution is shown to be highly improbable because in this case these typical symmetries are broken. Additionally, some remarks explaining implicit time-asymmetry of the Boltzmann Stosszahlansatz are made.
We present the first study of light induced atom desorption (LIAD) of an alkali atom (Rb) in poro... more We present the first study of light induced atom desorption (LIAD) of an alkali atom (Rb) in porous alumina. We observe the variation due to LIAD of the rubidium density in a vapor cell as a function of illumination time, intensity and wavelength. The simple and regular structure of the alumina pores allows a description of the atomic diffusion in the porous medium in which the diffusion constant only depends on the known pore geometry and the atomic sticking time to the pore wall. A simple one-dimensional theoretical model is presented which reproduces the essential features of the observed signals. Fitting of the model to the experimental data gives access to the diffusion constant and consequently the atom-wall sticking time and its dependence on light intensity and wavelength. The non-monotonic dependence of the LIAD yield on the illumination light frequency is indicative of the existence of Rb clusters in the porous medium.
Acta Physica Polonica A, 2021
The phenomenon of static friction is demonstrated in some challenging situations. The work-energy... more The phenomenon of static friction is demonstrated in some challenging situations. The work-energy theorem and the center-mass equation are elucidated and clearly discerned when used and interpreted in problems with static friction. Especially, it is demonstrated that it is indispensable to refer to thermodynamics to provide a complete and adequate description of some seemingly purely mechanical problems with static friction involved. The static frictional force, although being a zero-work force, is proved to influence energy acquired by a system. Unexpected values and directions of the static frictional forces are shown for some specific cases. Finally, it is explained how static friction plays a crucial role in the working of a store security tag, a device commonly used at clothes shops to prevent theft.
American Journal of Physics, 2010
Besides the well known scalar invariants, there exist also vectorial invariants in the realm of s... more Besides the well known scalar invariants, there exist also vectorial invariants in the realm of special relativity. It is shown that the three-vector d p dt v +γ v d p dt ⊥v is invariant under the Lorentz transformation. The indices v and ⊥v denote the respective components established with respect to the direction of the velocity of body v, and p is the relativistic momentum. We prove that this vector is equal to a force of F R satisfying the classical Newtonian law F R = m a R in the instantaneous inertial rest frame of an accelerated body. Therefore the equation F R = d p dt v + γ v d p dt ⊥v , based on the Lorentz-invariant vectors, may be used as a truly invariant (not merely a covariant) relativistic equation of motion in any inertial system of reference. An alternative approach to classical electrodynamics based on the invariant three-vectors is proposed.
Polimery, 2008
Formation of surface and inclusion complexes of single-walled carbon nanotubes (SWCNT) with dextr... more Formation of surface and inclusion complexes of single-walled carbon nanotubes (SWCNT) with dextrans of M w 6000 to 2 000 000 was proven spectrally, rheologically, and calorimetrically. Band shifts in the Raman spectra, increase in the viscosity of aqueous ...
International Agrophysics
The aim of the study was to describe the distribution of pea root mass in the soil, over a three-... more The aim of the study was to describe the distribution of pea root mass in the soil, over a three-year period, under varying weather conditions and at different levels of phosphorus application, by means of evaluating and comparing parameters of a mathematical model characterising cumulative root mass distribution. A two-factor experiment was conducted in Prusy, near Krakow: the first factor was the level of phosphorus application (0-70-140 kg P2O5 ha−1) and the second was the cultivars (six cultivars were tested). Experimental data produced using the model indicated that the root distribution was strongly differentiated by water availability in the years of the study. This appeared in some cases to be a more important factor than phosphorus application rates. The estimated soil depth at which 50% of the root mass was accumulated differed significantly for the dry and the wet year. In the wet year, only very high phosphorus application rates contributed to an increase in root mass di...
Starting from the classical Newton's second law which, according to our assumption, is valid ... more Starting from the classical Newton's second law which, according to our assumption, is valid in any instantaneous inertial rest frame of body that moves in Minkowskian space-time we get the relativistic equation of motion vecF=dvecp/dt\vec{F}=d\vec{p}/dtvecF=dvecp/dt, where vecp\vec{p}vecp is the relativistic momentum. The relativistic momentum is then derived without referring to any additional assumptions concerning elastic collisions of bodies. Lorentz-invariance of the relativistic law is proved without tensor formalism. Some new method of force transformation is also presented.
American Journal of Physics, 2015
ABSTRACT The spin of a gyroscope that undergoes Thomas precession seems to change its direction w... more ABSTRACT The spin of a gyroscope that undergoes Thomas precession seems to change its direction without any torque, which would mean that conservation of angular momentum is violated. To resolve this paradox, it is shown that the spin dynamics equation describing Thomas precession (the BMT equation) can be written in terms of a torque applied to the spin. A simple method of finding an explicit expression for the torque is presented in the case of a gyroscope performing circular motion. An unexpected oscillatory character of the torque is explained in terms of the difference between the proper spin and the spin observed in the laboratory frame.
The Physics Teacher, 2013
ABSTRACT Consider a skier who goes down a takeoff ramp, attains a speed V, and jumps, attempting ... more ABSTRACT Consider a skier who goes down a takeoff ramp, attains a speed V, and jumps, attempting to land as far as possible down the hill below (Fig. 1). At the moment of takeoff the angle between the skier's velocity and the horizontal is α. What is the optimal angle α that makes the jump the longest possible for the fixed magnitude of the velocity V? Of course, in practice, this is a very sophisticated problem; the skier's range depends on a variety of complex factors in addition to V and α. However, if we ignore these and assume the jumper is in free fall between the takeoff ramp and the landing point below, the problem becomes an exercise in kinematics that is suitable for introductory-level students. The solution is presented here.
Plant Cell, Tissue and Organ Culture, 2008
A theoretical model explaining the average DNA content in cells of in vitro cultures as a functio... more A theoretical model explaining the average DNA content in cells of in vitro cultures as a function of concentration of auxin 2,4-D in medium is provided. The model assumes influence of auxin on the functioning of the main G1/S and G2/M control points of the cell cycle. Theoretical results are compared to experimental data obtained from the callus cultures of Allium sativum and Allium cepa conducted during 18 months. Adaptation of the model to explanation of the shape of the doseresponse curves is suggested and successfully verified for the example of Nicotiana tabacum cultures. Keywords Auxin 2,4-D Á Cell cycle Á DNA content Á Dose response Á Theoretical model Abbreviations 2,4-D 2,4-Dichlorophenoxyacetic acid MS Murashige and Skoog (1962) medium NAA a-Naphthalene acetic acid TIR1 Transport inhibitor response protein 1 K. Rębilas (&)
Physical Review A, 2009
ABSTRACT The light-induced atomic desorption effect, known as LIAD, has been explained so far by ... more ABSTRACT The light-induced atomic desorption effect, known as LIAD, has been explained so far by a debatable Atutov’s theory [ S. N. Atutov et al. Phys. Rev. A 60 4693 (1999)]. In this Brief Report, we propose an approach in which the difficulties of this theory are removed. The theory yields predictions for the atomic vapor density n(t) in a fully illuminated resonance cell, the time tmax that it takes the vapor density to arrive at a maximum value nmax and the dependence of nmax and dn/dtt=+0 on the desorbing light intensity. Some of our results are at variance with outcomes of Atutov’s model (such as saturation effect for nmax and the dependence of tmax on the light intensity) but are in agreement with the experimental data. Additionally, the model presented in this Brief Report satisfactorily explains a reservoir effect recently investigated in experiments where cells equipped with a lockable stem were used.
Physical Review A, 2010
ABSTRACT In a recent article [Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.81.037801 81, 037801 (2... more ABSTRACT In a recent article [Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.81.037801 81, 037801 (2010)] a theory of light-induced atomic desorption for Rb in porous alumina is proposed. We point out that both the main assumption of this theory (the diffusion inside the pores treated as a random walk with the adsorption to the inner surface of the pores at any step) and several further hypotheses supporting the theoretical model require a revision.
Physical Review A, 2009
The commonly accepted theory of light-induced atomic desorption (LIAD) [S. N. Atutov , Phys. Rev.... more The commonly accepted theory of light-induced atomic desorption (LIAD) [S. N. Atutov , Phys. Rev. A 60, 4693 (1999)] explains the dynamics of this effect by referring to a light-enhanced diffusion process proceeding in the absorbing medium. On the other hand, recently performed measurements show that in siloxane films which are used in LIAD experiments, the characteristic time of diffusion is extremely short (a fraction of 1 s) compared to the duration of the LIAD effect (hundreds of seconds). This is in contradiction to the conceptual basis of the theory of Atutov that requires the characteristic diffusion time to be sufficiently long. What is more, the theory of Atutov relies on an unjustified assumption about the dependence of the diffusion coefficient on the light intensity. In consequence, the theoretical results of Atutov yield unsatisfactory predictions and do not fit well with experimental data. In this paper, we consider a partially illuminated siloxane-coated cell and propose an alternative theory of LIAD dynamics based on an assumption about lateral diffusion proceeding in the siloxane coating. Our theory provides a unique solution for the desorbed atoms' density regardless of the power of the laser light, explains the lengthy duration of LIAD, and accurately reproduces experimental results. A reasoning which explains how the boundary condition at the siloxane surface is established by the incident light gives us a proper relation between the desorbed atoms' density and the intensity of the desorbing light.
Foundations of Physics Letters, 2000
It is shown that Unnikrishnan's theory, which is believed to be a local realist theory resolving ... more It is shown that Unnikrishnan's theory, which is believed to be a local realist theory resolving the EPR puzzle, in two possible interpretations is either realist and nonlocal or local and non-realist.
Foundations of Physics, 2011
A direct method showing the Thomas precession for an evolution of any vector quantity (a spatial ... more A direct method showing the Thomas precession for an evolution of any vector quantity (a spatial part of a four-vector) is proposed. A useful application of this method is a possibility to trace correctly the presence of the Thomas precession in the Bargmann-Michel-Telegdi equation. It is pointed out that the Thomas precession is not incorporated in the kinematical term of the Bargmann-Michel-Telegdi equation, as it is commonly believed. When the Bargmann-Michel-Telegdi equation is interpreted in curved spacetimes, this term is shown to be equivalent to the affine connection term in the covariant derivative of the spin four-vector evolving in a gravitational field. It then contributes to the geodetic precession. The described problem is an interesting and unexpected example showing that approximate methods used in special relativity, in this case to identify the Thomas precession, can distort the true meaning of physical laws.
Food Hydrocolloids, 2006
Viscosity of aqueous solutions of dextrans of M w 19,500, 71,400, and 282,000 is fairly insensiti... more Viscosity of aqueous solutions of dextrans of M w 19,500, 71,400, and 282,000 is fairly insensitive to admixed L-arabinose, lactose, rhamnose, sorbitol, and xylitol. These results, together with results of polarimetric studies, suggested that a subtle increase in the viscosity of solutions, accompanied with increase in concentration of the additive was induced by changes in water activity rather than direct interactions between dextrans and additives.