A behavior-oriented diffusion model, governing the time evolution of the cross-shore position of coastal profiles, is studied. Here, two time-independent, space-varying coefficients, which embody the relevant physical properties, are identified simultaneously. Two sets of real data, the first measured over 10 years at Duck, in NC (USA), the second obtained over 39 years measurements at Delfland (Holland), have been processed numerically by a suitable “inversion algorithm”, earlier developed by the authors. This is based on the minimization of a certain cost functional in order to identify both coefficients. The numerical results, obtained by solving the diffusion equation with the so-determined coefficients, favorably agree with the real data, which fact validates and calibrates somehow the diffusion model under investigation. A short-term prediction is finally obtained for coastal profiles, using such a model.

A special system for mareogram processing is proposed. Such a system is based on two different approaches, namely, neural network technique, and inverse problems. By using two alternative methods, it is possible to achieve better accuracy in determining space parameters of a tsunami source. The above mentioned approaches are described in the paper. Model numerical tests, processed over the realistic depth profile, are then demonstrated.

The Maxwell and Lame systems are considered in the case when the electromagnetic (EM) field is generated by elastic oscillations. We neglect the reverse influence of the EM field on the elastic oscillations. The influence of the EM field on the deformation field is considered as a result of the Lorentz forces. We consider the problem of recovering some elastic and EM parameters of a layered medium from a weakly coupled linearized set of equations of electromagnetoelasticity. To solve the inverse problem for electromagnetoelasticity equations optimization methods are used.

Article Numerical solution of some direct and inverse problems of electromagnetoelasticity was published on January 1, 1999 in the journal Journal of Inverse and Ill-posed Problems (volume 7, issue 5).

A numerical method for solution of the inverse problem for the equations of electromagnetoelasticity is described. We consider the case when electromagnetic waves are generated by elastic deformations and neglect the reverse influence of the electromagnetic field on elastic oscillations. The solution of the inverse problem (unknown elastic and electromagnetic parameters of the medium) is sought by minimization of the data misfit functionals which are the mean square deviations of registered fields from the fields calculated for some "test" models of the medium.

One of the possible statements of inverse problems connected with electrodynamics of vibrating elastic media is considered. The motion of an elastic conductive medium in the electromagnetic field is described by two sets of equations: that of elasticity and that of electrodynamics. The waves arising in the result of this interaction are usually referred to as electromagnetoelastic. These waves contain information about both electromagnetic and elastic parameters of a medium. The electromagnetic wave rides the "back" of the seismic wave, that is, the induced electromagnetic wave is "frozen" into the seismic wave and propagates either with P- or with S- seismic wave velocity, depending on the type of waves. The dominant frequency and the velocity of the induced seismo-magnetic wave is equal to the frequency and velocity of the seismic wave. L. Knopoff [1] studied the influence of electromagnetic fields on the propagation of elastic waves and arrived at the conclusion that in the class of geophysical problems the effect of electromagnetic phenomena on the process of elastic waves propagation is negligible, at least in the case of not too large electromagnetic disturbances.

The given work deals with the problem of combined inversion of wave and electromagnetic fields. It was assumed that there exists the functional relation between the velocity and electric conductivity. However, the constants of the correlational dependence are given not precisely. The distributions of velocity and conductivity chosen such that the minimization process of data misfit functionals for the individual problems could not bring to a satisfactory solution. The complex functional containing a number of free parameters was used. Changing these parameters, we managed to do away with the strong ravine structure of the individual functionals in the combined functional and reconstruct the distributions of velocity and conductivity with a good accuracy.

Abundance, morphological composition, vertical distribution, production and activity of total bacterioplankton and its specific groups in the Black Sea were investigated in August–September 1989. The total bacterioplankton was highest in the upper mixed layer (0.7–1 × 106 cells ml−1), corresponding to that in mesotrophic basins. In the N-E shallow part of the sea it attained 3 × 106. Below the thermocline (50–100 m) the total number of bacteria decreased to 0.2–0.4 × 106 ml−1. In the redox gradient zone (zone of O2-H2S interface), it increased again. In deep anoxic waters the bacterioplankton, numbering 0.15–0.2 × 106 ml−1, was functionally inactive. Its biomass was 12–40 mg C m−3 in the upper mixed layer, 5–10 mg C m−3 in the intermediate cold layer (40–100 m depth), and 10–20 mg C−3 in the redox zone. Maximum production rates occurred in the upper mixed layer (8–20 mg C−3 d−1) and in the redox-zone, 80–90% of it was due to chemosynthesis of thiobacilli. Below 200 m, microbial production decreased to about zero in the anoxic zone. Maximum activity of heterotrophic bacteria was recorded in the upper mixed layer, while thiobacilli and methaneoxidezing bacteria were most active in the redox-zone. Here, the maximum rates of H2S and of thiosulfate oxidation, as well as maximum sulfate reduction were recorded. Chemical oxidation of H2S was dominant. These results are discussed with respect to the present ecological situation of the Black Sea.

The authors describe a closed cycle of mathematical modelling of wave propagation processes. The half-space z>0 is assumed to be filled with a vertically-inhomogeneous medium with the wave propagation velocity c(z). A source located on the free surface z=0 causes the wave process U(x,y,z,t), described by the initial boundary value problem for the wave equation. They consider two main problems: (1) Assuming c*(z) is known for all z, the authors wish to calculate the wave field U(x,y,z,t); (2) If c*(z) is unknown, they find it using the additional information U(x,y,t)=U(x,y,0,t). In order to solve problem (2) the optimization approach is proposed and verified. Uniqueness and stability of the minimum point of the data misfit functional are proved and convergence of iterative methods for its search is investigated. The search for the minimum point in the domain of space-time frequencies can essentially increase the efficiency of the whole process of finding the velocity c(z).

A number of publications dealing with the optical-band quantum electronics (OBQE) since 1963 till 1987 has been counted by studying the content of the Soviet abstract journal "Physics". It has been found that the rate of growth of the whole complex of publications on the OBQE increases to the end of 1980s; the rates of growth of the number of publications on different trends of the OBQE differ considerably; beginning with the end of 1970s the volume of publications on general problems of the OBQE and on the theory grows faster than that on laser applications; within the last 10-15 years the number of publications on gas lasers is distinguished by the greatest temporal dynamism, that on glass lasers-by the least one.

The inverse dynamic problem for the wave equation in the class of vertically inhomogeneous media is considered in this paper. It is required to determine the unknown wave propagation velocity c(z). Solution of this problem is sought for as the minimum point of the data misfit functional. Stability of the minimum point is analyzed depending on the initial approximation and ranges of spatial and time frequencies. The results of numerical experiments for two models are given.

ChemInformVolume 20, Issue 39 Isocyclic Compounds ChemInform Abstract: Hydrogenation and Isomerization of Allylbenzene in the Presence of the Catalytic System (Cp2TiCl)2-LiAlH4. A. V. AVDEEV, A. V. AVDEEV Inst. org. khim. im. Zelinskogo AN SSSR, MoskvaSearch for more papers by this authorL. I. GVINTER, L. I. GVINTER Inst. org. khim. im. Zelinskogo AN SSSR, MoskvaSearch for more papers by this authorV. Z. SHARF, V. Z. SHARF Inst. org. khim. im. Zelinskogo AN SSSR, MoskvaSearch for more papers by this author A. V. AVDEEV, A. V. AVDEEV Inst. org. khim. im. Zelinskogo AN SSSR, MoskvaSearch for more papers by this authorL. I. GVINTER, L. I. GVINTER Inst. org. khim. im. Zelinskogo AN SSSR, MoskvaSearch for more papers by this authorV. Z. SHARF, V. Z. SHARF Inst. org. khim. im. Zelinskogo AN SSSR, MoskvaSearch for more papers by this author First published: September 26, 1989 https://doi.org/10.1002/chin.198939137AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume20, Issue39September 26, 1989 RelatedInformation