A Novel Approach to Predict Field Strength in the Shadow of a 3-D Building Scenario

A novel approach to predict field strength in the shadow of a 3-D building scenario is presented. The field strength predicted by the proposed model is compared with available measurements and earlier predicted fields based on Fresnel-Kirchhoff theory. Two different scenarios have been considered to validate our model. The proposed model gives an improvement of 7.7 dB for Scenario 1; and 5.8 dB for Scenario 2. A good agreement between the prediction and the measurement is also observed.     

Singular points and singular lines in problems of diffraction by bodies with an anisotropic impedance

The effect (earlier discovered) of penetration of an electromagnetic-field power flux into a wall exhibiting perfect mixed anisotropic conductivity is considered in more detail. It is shown that the power transmitted into the screen through the nodes of conductivity lines and through resonance-length closed contours can be regarded as the limit value of the power absorbed in a wall characterized by an anisotropic impedance when the absorbing impedance approaches the values corresponding to the case of perfect mixed conductivity.     

Ultrasonic Evaluation of Adhesive Bonding

The capabilities of existing ultrasonic nondestructive evaluation (NDE) methods for the strength-related properties of bonds in structural components is reviewed. The severe limitations of conventional NDE methods in yielding quantitative results are indicated. Some recent results of a joint theoretical and experimental program of research using leaky Lamb waves (LLW) in laboratory specimens are presented. The LLW technique is shown to have several advantages over conventional techniques. Potential applications of the technique to determine non-destructively the quality of bonds in a variety of models are discussed.     

Heat transfer during boiling of a liquid metal during emergency cooldown of a fast-neutron reactor

The physics of the processes, the characteristics, and the stability of different regimes, of boiling (nucleate, projectile, disperse-ring), which are observed in experiments investigating the boiling of liquid-metal coolant in a model of a fuel assembly for a fast-neutron reactor in the emergency cooldown regime with low circulation velocity, are analyzed. The experimental setup, the, methods for performing measurements, and the experimental data on the boiling of a liquid metal are described. A mathematical model of the process of boiling of a liquid-metal, coolant in a natural-circulation loop is described, and the results of test calculations for regimes with an increase in heating and with sharp pressure drop are prresented. 7 figures, 12 references. State Science Center of the Russian Federration–A. I. Leipunskii Physics and Power Engineering Institute. Translated from Atomnaya énergiya, Vol. 87, No. 5, pp. 337–342, November, 1999.     

Direct and reverse elastic aftereffects of spring ribbon from nitrogen-bearing steel Kh21G10N7MBF

Direct and reverse elastic aftereffects in corrosion-resistant nitrogen-bearing steel Kh21G10N7MBF (0.5% N) are considered depending on the preliminary heat treatment (quenching + deformation + aging) and on the temperature and time conditions of the occurrence of the direct and reverse elastic aftereffects. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 1, pp. 8–11, January, 2006.     

A microwave scattering model for layered vegetation

A microwave scattering model was developed for layered vegetation based on an iterative solution of the radiative transfer equation up to the second order to account for multiple scattering within the canopy and between the ground and the canopy. The model is designed to operate over a wide frequency range for both deciduous and coniferous forest and to account for the branch size distribution, leaf orientation distribution, and branch orientation distribution for each size. The canopy is modeled as a two-layered medium above a rough interface. The upper layer is the crown, containing leaves, stems, and branches. The lower layer is the trunk region, modeled as randomly positioned cylinders with a preferred orientation distribution above an irregular soil surface. Comparisons of results obtained using this model with measurements from deciduous and coniferous forests show good agreement at several frequencies for both like and cross polarizations