Emitter near an arbitrary body: Purcell effect, optical theorem and the Wheeler-Feynman absorber

The altered spontaneous emission of an emitter near an arbitrary body can be elucidated using an energy balance of the electromagnetic field. From a classical point of view it is trivial to show that the field scattered back from any body should alter the emission of the source. But it is not at all apparent that the total radiative and non-radiative decay in an arbitrary body can add to the vacuum decay rate of the emitter (i.e.) an increase of emission that is just as much as the body absorbs and radiates in all directions. This gives us an opportunity to revisit two other elegant classical ideas of the past, the optical theorem and the Wheeler-Feynman absorber theory of radiation. It also provides us alternative perspectives of Purcell effect and generalizes many of its manifestations, both enhancement and inhibition of emission. When the optical density of states of a body or a material is difficult to resolve (in a complex geometry or a highly inhomogeneous volume) such a generalization offers new directions to solutions.Comment: 18 pages, 2 figure

Quasichemical Models of Multicomponent Nonlinear Diffusion

Diffusion preserves the positivity of concentrations, therefore, multicomponent diffusion should be nonlinear if there exist non-diagonal terms. The vast variety of nonlinear multicomponent diffusion equations should be ordered and special tools are needed to provide the systematic construction of the nonlinear diffusion equations for multicomponent mixtures with significant interaction between components. We develop an approach to nonlinear multicomponent diffusion based on the idea of the reaction mechanism borrowed from chemical kinetics. Chemical kinetics gave rise to very seminal tools for the modeling of processes. This is the stoichiometric algebra supplemented by the simple kinetic law. The results of this invention are now applied in many areas of science, from particle physics to sociology. In our work we extend the area of applications onto nonlinear multicomponent diffusion. We demonstrate, how the mechanism based approach to multicomponent diffusion can be included into the general thermodynamic framework, and prove the corresponding dissipation inequalities. To satisfy thermodynamic restrictions, the kinetic law of an elementary process cannot have an arbitrary form. For the general kinetic law (the generalized Mass Action Law), additional conditions are proved. The cell--jump formalism gives an intuitively clear representation of the elementary transport processes and, at the same time, produces kinetic finite elements, a tool for numerical simulation.Comment: 81 pages, Bibliography 118 references, a review paper (v4: the final published version

CHARACTERISTICS OF 2017 HOJEDK EARTHQUAKE SEQUENCE IN KERMAN PROVINCE, SOUTHEAST IRAN

Kerman province in southeast Iran, has experienced historical and instrumentally recorded earthquakes. In December 2017, three destructive earthquakes have occurred around Hojedk, in Kerman within 11 days. In this study, first the regional seismotectonics and seismicity is presented. Then, the source mechanisms of main shocks are modeled and the results are compared with the active faults and seismicity pattern is discussed. Moment tensor inversion in time domain is used to obtain the source mechanism of earthquakes. The results indicate that the mechanisms of main shocks and aftershocks are mainly reverse and are in agreement with the trend of tectonic forces as well as the mechanisms of other earthquakes. The epicentral distribution of aftershocks indicates two clusters. The spatial distributions of clusters are in agreement with the epicentral distribution of main shocks. The cluster around the first earthquake in EW cross section has a length 15-20 Km, while the cluster around the second and third has a length about 20-25 Km. The Hojedk earthquakes occurred along the northern extension of previous earthquakes where a kind of seismic gap could be observed and still exists. In 1972, within five days four earthquakes with magnitudes 5.5 to 6.2 occurred in Sefidabeh region in eastern edge of Lut block. In both regions earthquakes have reverse mechanisms and associated with surface ruptures. Thus, it could be concluded that the energy was mainly released with several moderate earthquakes in adjacent faults. In northern extensions of both regions, seismic gaps still could be observed and major earthquakes might occur in future.A província de Kerman, no sudeste do Irã, é uma região que apresenta terremotos históricos registrados. Em dezembro de 2017, três terremotos destrutivos ocorreram em torno de Hojedk, em Kerman, durante o período de 11 dias. Neste estudo, em um primeiro momento é apresentada a sismotectônica regional e a sismicidade dessa região. Em seguida, os mecanismos de origem dos choques principais são modelados e os resultados são comparados com as falhas ativas e o padrão de sismicidade é discutido. A inversão do tensor de momento no tempo é usada para obter o mecanismo de origem dos terremotos. Os resultados indicam que os mecanismos dos principais choques e primários e secundários são principalmente de origem reversa e estão de acordo com a tendência das forças tectônicas, bem como com os mecanismos de outros terremotos. A distribuição epicentral dos tremores secundários indicam dois grupos. As distribuições espaciais em clusters estão de acordo com a distribuição epicentral dos choques principais. O aglomerado em torno do primeiro terremoto na seção transversal EW tem um comprimento de 15-20 Km, enquanto o aglomerado em torno do segundo e terceiro tem um comprimento de cerca de 20-25 Km. Os terremotos de Hojedk ocorreram ao longo da extensão norte do local onde foram registrados terremotos anteriores, onde uma espécie de lacuna sísmica pode ser observada e ainda existente. Em 1972, em cinco dias, quatro terremotos com magnitudes de 5,5 a 6,2 ocorreram na região de Sefidabeh na borda leste do bloco de Lut. Em ambas as regiões, os terremotos têm mecanismos reversos e associados a rupturas de superfície. Assim, pode-se concluir que a energia foi liberada principalmente com vários tremores moderados em falhas adjacentes. Em extensões ao norte de ambas as regiões, lacunas sísmicas ainda podem ser observadas e grandes terremotos podem ocorrer no futuro

CHARACTERISTICS OF 2017 HOJEDK EARTHQUAKE SEQUENCE IN KERMAN PROVINCE, SOUTHEAST IRAN

Kerman province in southeast Iran, has experienced historical and instrumentally recorded earthquakes. In December 2017, three destructive earthquakes have occurred around Hojedk, in Kerman within 11 days. In this study, first the regional seismotectonics and seismicity is presented. Then, the source mechanisms of main shocks are modeled and the results are compared with the active faults and seismicity pattern is discussed. Moment tensor inversion in time domain is used to obtain the source mechanism of earthquakes. The results indicate that the mechanisms of main shocks and aftershocks are mainly reverse and are in agreement with the trend of tectonic forces as well as the mechanisms of other earthquakes. The epicentral distribution of aftershocks indicates two clusters. The spatial distributions of clusters are in agreement with the epicentral distribution of main shocks. The cluster around the first earthquake in EW cross section has a length 15-20 Km, while the cluster around the second and third has a length about 20-25 Km. The Hojedk earthquakes occurred along the northern extension of previous earthquakes where a kind of seismic gap could be observed and still exists. In 1972, within five days four earthquakes with magnitudes 5.5 to 6.2 occurred in Sefidabeh region in eastern edge of Lut block. In both regions earthquakes have reverse mechanisms and associated with surface ruptures. Thus, it could be concluded that the energy was mainly released with several moderate earthquakes in adjacent faults. In northern extensions of both regions, seismic gaps still could be observed and major earthquakes might occur in future.A província de Kerman, no sudeste do Irã, é uma região que apresenta terremotos históricos registrados. Em dezembro de 2017, três terremotos destrutivos ocorreram em torno de Hojedk, em Kerman, durante o período de 11 dias. Neste estudo, em um primeiro momento é apresentada a sismotectônica regional e a sismicidade dessa região. Em seguida, os mecanismos de origem dos choques principais são modelados e os resultados são comparados com as falhas ativas e o padrão de sismicidade é discutido. A inversão do tensor de momento no tempo é usada para obter o mecanismo de origem dos terremotos. Os resultados indicam que os mecanismos dos principais choques e primários e secundários são principalmente de origem reversa e estão de acordo com a tendência das forças tectônicas, bem como com os mecanismos de outros terremotos. A distribuição epicentral dos tremores secundários indicam dois grupos. As distribuições espaciais em clusters estão de acordo com a distribuição epicentral dos choques principais. O aglomerado em torno do primeiro terremoto na seção transversal EW tem um comprimento de 15-20 Km, enquanto o aglomerado em torno do segundo e terceiro tem um comprimento de cerca de 20-25 Km. Os terremotos de Hojedk ocorreram ao longo da extensão norte do local onde foram registrados terremotos anteriores, onde uma espécie de lacuna sísmica pode ser observada e ainda existente. Em 1972, em cinco dias, quatro terremotos com magnitudes de 5,5 a 6,2 ocorreram na região de Sefidabeh na borda leste do bloco de Lut. Em ambas as regiões, os terremotos têm mecanismos reversos e associados a rupturas de superfície. Assim, pode-se concluir que a energia foi liberada principalmente com vários tremores moderados em falhas adjacentes. Em extensões ao norte de ambas as regiões, lacunas sísmicas ainda podem ser observadas e grandes terremotos podem ocorrer no futuro

THE EFFECT OF MYOELECTRIC STIMULATION ON PERONEAL MUSCLES TO RESIST SUDDEN SIMULATED ANKLE SPRAIN MOTIONS

This study evaluated the effect of myoelectric stimulation on peroneal muscles to resist sudden simulated ankle sprain motions. Ten male subjects performed unanticipated inversion and supination spraining motions simulated by a mechanical sprain simulator. Myoelectric stimulations with different delay time were delivered to the peroneal muscles to initiate involuntary muscle contraction and ankle joint pronation torque to resist the spraining motion. The motion was captured and analyzed by a motion analysis system, and was quantified by the reduction of maximum heel tilting angle and angular velocity. Results showed significant effect in all conditions with the myoelectric stimulation of any delay time within 15ms. The maximum heel tilting angle and angular velocity dropped from 18 to 9-13 degrees and from 200-250 to 140-170 degree/s respectively. The present corrective mechanism could be implemented in our current research to develop an intelligent sprain-free sport shoe attempting to prevent ankle sprain injury in sports