Stochastic Pulse Switching in a Degenerate Resonant Optical Medium

Using the idealized integrable Maxwell-Bloch model, we describe random optical-pulse polarization switching along an active optical medium in the Lambda-configuration with disordered occupation numbers of its lower energy sub-level pair. The description combines complete integrability and stochastic dynamics. For the single-soliton pulse, we derive the statistics of the electric-field polarization ellipse at a given point along the medium in closed form. If the average initial population difference of the two lower sub-levels vanishes, we show that the pulse polarization will switch intermittently between the two circular polarizations as it travels along the medium. If this difference does not vanish, the pulse will eventually forever remain in the circular polarization determined by which sub-level is more occupied on average. We also derive the exact expressions for the statistics of the polarization-switching dynamics, such as the probability distribution of the distance between two consecutive switches and the percentage of the distance along the medium the pulse spends in the elliptical polarization of a given orientation in the case of vanishing average initial population difference. We find that the latter distribution is given in terms of the well-known arcsine law

Effect of an Optical Negative Index Thin Film on Optical Bistability

We investigate nonlinear transmission in a layered structure consisting of a slab of positive index material (PIM) with Kerr-type nonlinearity and a sub-wavelength layer of linear negative index material (NIM) sandwiched between semi-infinite linear dielectrics. We find that a thin layer of NIM leads to significant changes in the hysteresis width when the nonlinear slab is illuminated at an angle near that of total internal reflection. Unidirectional diode-like transmission with enhanced operational range is demonstrated. These results may be useful for NIMs characterization and for designing novel NIMs based devices

Negative diffraction pattern dynamics in nonlinear cavities with left-handed materials

We study a ring cavity filled with a slab of a right-handed material and a slab of a left-handed material. Both layers are assumed to be nonlinear Kerr media. First, we derive a model for the propagation of light in a left-handed material. By constructing a mean-field model, we show that the sign of diffraction can be made either positive or negative in this resonator, depending on the thicknesses of the layers. Subsequently, we demonstrate that the dynamical behavior of the modulation instability is strongly affected by the sign of the diffraction coefficient. Finally, we study the dissipative structures in this resonator and reveal the predominance of a two-dimensional up-switching process over the formation of spatially periodic structures, leading to the truncation of the homogeneous hysteresis cycle.Comment: 8 pages, 5 figure

Investigation of Benthic Foraminiferal Non-Traditional Stable Isotopes to Reconstruct Methane Fluxes in Sedimentary Environments

Methane (CH4) is an important greenhouse gas, with a global warming potential much higher than carbon dioxide (CO2) on a short time scale. Even if the residence time of CH4 in the atmosphere is relatively short (tens of years), one of the products of CH4 oxidation is CO2, a greenhouse gas with a much longer residence time in the atmosphere (tens to hundreds of years). CH4 has been proposed as one of the trigger mechanisms for rapid global climate change today and in the geological past. With regards to the geological past, numerous studies proposed the benthic foraminiferal carbon isotope ratio (Delta13C) as a tool to reconstruct the impact of marine CH4 on rapid climate changes; however, the investigation of modern benthic foraminiferal Delta13C have produced inconclusive results. CH4 has a distinctive hydrogen isotope (Delta(D)) and Delta13C signature compared to seawater, and sulfate reduction, often coupled to CH4 anaerobic oxidation in sediments, changes the sulfur isotope signature (Delta34S) of the remaining sulfate in porewater. Therefore, we hypothesize that the Delta(D) and Delta34S signature of infaunal benthic foraminiferal species can provide a complementary approach to Delta13C to study CH4 dynamics in sedimentary environments. Here, we present the preliminary results obtained analyzing Uvigerina peregrina Delta(D) and Delta34S from three different locations at Hydrate Ridge, offshore Oregon. Unfortunately, the lack of chemical data related to the moment of foraminiferal calcification makes difficult to build a robust relationship among the U. peregrina stable isotopes and the CH4 fluxes at the sampling sites. However, our results look very promising, as each site is characterized by a different Delta(D) and Delta34S signature. We emphasize that this study represents the first step in the development of new proxies (Delta(D)) and Delta34S), which may complement the more traditional benthic foraminiferal Delta13C values, to reconstruct marine CH4 fluxes in the geological past

Theory of Pump Depletion and Spike Formation in Stimulated Raman Scattering

By using the inverse spectral transform, the SRS equations are solved and the explicit output data is given for arbitrary laser pump and Stokes seed profiles injected on a vacuum of optical phonons. For long duration laser pulses, this solution is modified such as to take into account the damping rate of the optical phonon wave. This model is used to interprete the experiments of Druhl, Wenzel and Carlsten (Phys. Rev. Lett., (1983) vol. 51, p. 1171), in particular the creation of a spike of (anomalous) pump radiation. The related nonlinear Fourier spectrum does not contain discrete eigenvalue, hence this Raman spike is not a soliton.Comment: LaTex file, includes two figures in LaTex format, 9 page

Productivity of corn Ross 140 depending on the level of the chemicalization of zonal soils of the republic of Tatarstan

It is known that one and the same corn plant material can be used to produce silage, cornage, milled grain, or grain for fodder. Each of them contains completely different amounts of nutrients and a wide range of gross yield of fodder units. The results of the research show the direct dependence of the choice of corn use on zonal features of the soil cover and the existing level of chemicalization of agricultural formations of the Republic of Tatarstan, which are considered in detail in this paper. Thus, in order to produce the ploughed grain or corn with the gross harvest of fodder units 7.94–8.82 t/ha and profitability of 78.7% on leached chernozems, which account for 38% of soils of the Republic of Tatarstan, it is recommended to cultivate corn using the complex application of agromeliorants and calculated norms of mineral fertilizers. Liming of acidic dark gray and gray forest soils with phosphorite and zeolite application in combination with NPK provides increase in gross harvest of fodder units of corn silage from 4.22 to 6.13 and 3.34 to 5.86 t/ha respectively. The high efficiency of agrochemicals application on corn crops and forage harvesting of different types of fodder taking into account zonal features of soil cover of the Republic of Tatarstan is also confirmed by economic indicators. The profitability of production of rolled grain reaches the maximum value (78.8%) in the variant with liming and phosphating of leached chernozem combined with the application of mineral fertilizers in rates calculated for obtaining the planned 35 t/ha of green mass. At the same time, on dark gray and gray forest soils as the yield of green mass increases under the influence of agromeliorants the total costs of silage production increases by 13.1 and 16.5 thousand rubles/ha compared with the control variants of the experiment (without agrochemicals). However, the costs of production of 1 000 fodder units are reduced to 9.9 and 10.4 thousand rubles respectively, provided that the sale price is about14 thousand rubles

RESEARCH OF DRYING SOLID WASTE

The mathematical model heat and mass transfer in a layer of solid waste, which allows you to explore the process of drying. The model allows the calculation of temperature fields in the layer of solid waste in the process of drying, taking into account the distributed internal heat sink. The proposed model can be applied in the calculations for the design of the thermal reactor for processing multicomponent organic waste.Предложена математическая модель тепломассопереноса в слое ТБО, которая позволяет исследовать процесс его сушки. Модель позволяет рассчитать температурные поля в слое ТБО в процессе его сушки с учетом распределенного внутреннего стока теплоты. Предложенная модель может быть применена в расчетах при проектировании термических реакторов для переработки многокомпонентных органических отходов

RESEARCH OF SOLID WASTE PYROLYSIS IN THE THERMAL REACTOR OF MINE TYPE

In this work was to investigate the process of pyrolysis of municipal solid waste morphological composition of medium, in order to determine the effective heat of pyrolysis.В работе был исследован процесс пиролиза твердых бытовых отходов среднего морфологического состава, с целью определения эффективной теплоты пиролиза

IMPROVING THE EFFICIENCY OF WORK OF A THERMAL REACTOR FOR DISPOSAL OF SOLID WASTES

The paper presents the results of the calculation of the gas output when the moisture content of municipal solid waste in the process of their disposal. The design of a shaft-type thermal reactor for utilization of solid municipal waste has been proposed.В работе изложены результаты расчета выхода газа при изменении влажности твердых коммунальных отходов в процессе их утилизации. Предложена конструкция термического реактора шахтного типа для утилизации твердых коммунальных отходов

Application of microprocesses method for determining the effective coefficient of the temperature conductivity of solid municipal wastes

A calculation and experimental technique for determining the effective coefficient of thermal diffusivity of a mixture of municipal solid waste (MSW) during their drying is proposed. Dependences of the effective coefficient of thermal diffusivity on temperature are obtained for different values of the porosity of the layer.Предложена расчетно-экспериментальная методика определения эффективного коэффициента температуропроводности смеси твердых коммунальных отходов (ТКО) в процессе их сушки. Получены зависимости эффективного коэффициента температуропроводности от температуры при различных значениях порозности слоя