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Самовозгорание угля остается важной проблемой для угольных шахт, которая может привести к взрыву метана и угольной пыли. Аварии, связанные с самовозгоранием угля, могут нанести угледобывающим компаниям значительные экономические убытки, а также влекут за собой социальный ущерб – травмы и гибель людей. На шахтах Кузбасса известны аварии, произошедшие в результате халатного отношения к опасности возникновения очагов самовозгорания угля, жертвами которых стали десятки человек. Анализ аварийных ситуаций, связанных с самовозгоранием угля, показывает, что существующий широкий спектр средств профилактики эндогенных пожаров не обеспечивает полную безопасность при отработке пластов угля, склонного к самовозгоранию, поэтому в шахтах продолжают возникать очаги самовозгорания. Последствия, которые могут возникнуть в результате взрыва метана, инициированного очагом самовозгорания, указывают на необходимость совершенствования применяемых технологий. Цель работы – определить влияние современных технологических решений, применяемых на действующих шахтах при подземной отработке пологих пластов угля, склонного к самовозгоранию, и разработать новые решения, позволяющие снизить эндогенную пожароопасность. Представлены выводы о влиянии оставления целиков угля в выработанном пространстве, изолированного отвода воздуха из очистного забоя по выработанному пространству, длины очистного забоя и выемочного столба и других факторов на опасность формирования очагов самовозгорания. Также сделаны выводы о возможности использования современных технологических решений в будущем.

We describe and analyze the experimental realization of the speckle interferometry scheme designed to measure deformation of an object surface. It can be shifted along the surface itself as well as turned or inclined. In contrast to the classical speckle interferometric schemes, we use a specially formed two-dimensional pattern of random binary structure as a speckle structure. The pattern being illuminated by the white light is photographed with the use of a digital camera. Further processing of the information related to the Fourier transformation of the pictures registered and determination of the obtained fringe structure period is carried out in PC.© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

An analysis is made of a method for determination of the amplitude, phase, spectral, and time characteristics of laser radiation pulses. The method is based on recording two spectra of an investigated radiation pulse: the original pulse and that transformed by a filter with characteristics that vary with time. An analysis of the resultant distributions of the intensity in these two spectra then yields the amplitude and phase spectra and the structure of a pulse.

Currently, research work modelling of interface phenomena of nanoparticle-reinforced composite materials, notably Carbon Nanotubes (CNT)-epoxy composites are investigated across the length scales. This paper describes the kinematics of nanoparticle-reinforced composite materials as a continuum media, the formulation of governing equations (fundamentals) and the statement of boundary conditions for multi-scale modelling of the material. The identification problem for the non-classical parameters of the model has been solved by experimental results and a method of conjugated gradients. The model has been validated to predict some basic mechanical properties of a polymeric matrix reinforced with nanoscale particles/fibres/tubes (including CNT) as a function of size and also dispersion of nanoparticles. The outcome of this paper is expected to have wide-ranging technical benefits with direct relevance to industry in the areas of transportation (aerospace, automotive, rail, maritime) and civil infrastructure development.

A new method is proposed for an analysis of amplitude?phase characteristics of short laser radiation pulses. The method is based on determination of a pattern of the interference between the spectra of the investigated pulse and of a second pulse obtained from the original one by a frequency shift. An analysis of the intensity distribution in the spectral interference pattern can yield the phases of the spectral components, which?in combination with the conventional spectrum?provides complete information on the time dependence of the signal.

A theoretical and experimental investigation is made of the photoelectric recording and separation of a signal from a noise background by correlation processing of information carried by the optical fields. The Fourier transformation is operated by an optical method. Filtering and the inverse Fourier transformation are performed to obtain the correlation function during the recording process by using a transient reference wave with a linear frequency variation over its cross section and containing a spatial filter. This wave is formed by the quasilinear motion of a filter in the focal plane of a lens. The signal is recorded on an oscillograph screen.

An experiment to demonstrate the finite velocity of light (educational exhibit) J M Osborne STIMULATED RAMAN SCATTERING OF LIGHT Vladimir A Zubov, M M Sushchinski and I K Shuvalov Recent applications of lasers O S Heavens Doped-crystal and gas lasers D W Goodwin and O S Heavens Ruby laser damage associated with a liquid Raman frequency changer A J Gibson MODERN TRENDS IN THE SPECTROSCOPY OF RAMAN SCATTERING OF LIGHT Vladimir A Zubov, M M Sushchinski and I K Shuvalov Laser light scattering in laboratory plasmas D E Evans and J Katzenstein Frequency changing of laser radiation

A method was developed for recording a one-dimensional optical field pattern using a photoelectric detector with a large sensitive area. A transient reference wave was formed as a result of approximately linear and uniform motion of an aperture in the front focal plane of a lens. Model one-dimensional transparencies were recorded in this way. It was found that amplitude and phase information, carried by the optical field, could be stored in this way.

It is shown that the diffraction efficiencies are identical for holograms obtained using a time-dependent reference wave with a linear variation of the frequency in the cross section and of holograms recorded frame by frame; this is true for a single resolvable element and for the whole hologram. An analysis of the noise shows that the scattering of light in the recording material then plays a major role. However, the signal/noise ratio remains satisfactory even for a large number of resolvable time intervals. Moreover, considerable averaging of the noise pattern is possible in the observation of the reconstructed signal and this improves the signal/noise ratio.

An analysis is made of a photoelectric recording method based on the use of an unsteady reference wave. The object field is recorded after a preliminary conversion into a spatial spectrum, which is performed by an optical method. The signal can be recorded on magnetic tape, transmitted along communication channels, and reproduced as a transparency on the screen of an image converter. The field reconstructed from such a transparency is identical with the original object field. The proposed method makes it possible to reduce the amount of the information that has to be recorded. The object field can be recorded directly in difficult spectral regions. The inverse Fourier transformation is performed during the reconstruction in the visible part of the spectrum.

A description is given of a proposed system for continuous recording and reproduction of a holographic cine film. The system is based on the use of a uniformly moving photographic film and a reference wave formed by a diffuser.

A study was made of a holographic system for recording modulated optical signals with the aid of a time-dependent reference wave formed by linear motion of an element of a telescopic unit. The time-dependent interaction of an object with the optical signal was simulated by mechanical modulation. The theoretically calculated parameters of the system and the predicted recording and reconstruction data were in good agreement with the experimental values.

A description is given of a correlator utilizing a transient reference wave, double-beam interferometry, and photoelectric recording of output data. A single-frequency semiconductor injection laser is used as a light source. Such a correlator is a compact data-processing device in which the coherence requirements can be relaxed and in which light beams can be transformed differently in different channels.

A method is proposed for the reconstruction of an optical field with the aid of two transparencies. Information on the distribution of the amplitudes and phases of the optical field is recorded by directing radiation into two channels. The distribution of the field amplitudes is recorded in the usual way in one channel, whereas the other channel visualizes the phase distribution and ensures that it is recorded in a phase-sensitive material. Reconstruction involves illumination of these two transparencies used in combination with a plane monochromatic wave.

A scheme for recording information in a holographic memory is analyzed theoretically and implemented experimentally. It involves the use of a random scatterer imaged in the hologram plane. A high noise immunity of the scheme and a high diffraction efficiency of periodic transparencies are reported.

An analysis is made of the process of obtaining information on the spectrum of laser-radiation modulation resulting from the interaction between the radiation with an object or a substance. The process is based on holographic recording of the information on a transient signal and extraction of the spectral data. A theoretical analysis is made of the variant when the spectral resolution representing a fraction of a hertz is considerably greater than the width of the laser radiation spectrum. Experiments are reported to confirm the feasibility of the method and its high spectral resolution.

It is shown that interaction between an optical signal and a special nonmonochromatic reference wave with a bulk light-sensitive material can be used to record information on the spatial and temporal characteristics of the signal. Illumination of a hologram obtained in this way with a special reconstructing wave produces a three-dimensional time-dependent image of the original object. The amount of information which can be recorded in this way is calculated.