Scattering of electromagnetic waves with a grating of microstrip conductors on an anisotropic substrate

Translated from Izmeritel'naya Tekhnika, No. 2, pp. 45–46, February, 1992.     

A refined statistical approach to thermal fatigue life prediction

Finding new applications for ceramic materials requires a better knowledge of thermal fatigue behaviour. However, result-scattering inherent to thermal fatigue and duration of a thermal fatigue cycle lead to a lack of experimental results. For these reasons, we have developed a new approach that permits the determination of a relevant stress intensity factor exponent n with a minimum testing sample number. From knowledge of the distribution function of artificial cracks, the analytical formula of the failure probability F(N) can be completely determined. Thus, it is possible to calculate n from a correlation of F(N) with experimental results obtained for only one temperature difference. Correlations between theoretical curves F(N) and experimental results, conducted for two temperature differences, lead to the same value of n. This and the good agreement between the experimental points and the theoretical curves validate this new approach.     

Stabilization of high-impact polystyrene/ polyethylene blends

Commercial poly(styrene-b-butadiene) copolymers (SBS) can act as effective compatibilizers in blends between high-impact polystyrene (HIPS) and polyethylene (PE), allowing a fine dispersion of PE in the polystyrene matrix, with a good balance of stiffness and impact strength. However, when processed under more severe conditions (e.g. in multiple extrusions, which simulate customer's product scrap recovery), the above blends show rather poor stability and their useful properties are rapidly lost. That undesirable effect is mainly due to cross-linking of SBS, which thus looses its compatibilizing activity. A correlation has been found between the time-to-cross-linking of SBS rubber in a Brabender mixer and the rapid decay of mechanical properties. The analysis of the mixing process and the morphology examinations of the final blend sample by TEM seem to support the above hypothesis. A significant reduction of block copolymer degradation has been achieved by means of a suitable stabilization.     

Three-dimensional fracture simulation with a single-domain,direct boundary element formulation

An efficient hypersingular boundary integral equation method for three-dimensional fracture mechanics was presented in a previous paper. The details of the numerical implementation of this method are further discussed herein. In particular, an algorithm for achieving the required differentiability of the crack surface displacement function is discussed. To illustrate the utility of the method, computational results for several strongly interacting multiple-crack geometries are presented. The calculated stress intensity factors are in excellent agreement with those obtained by an approximate analytical method due to Kachanov and Laures.     

Scattering codes to implement short 3-secure fingerprinting forcopyright protection

Collusion attacks are a major issue in fingerprinting schemes for copyright protection. A new class of codes, called scattering codes, is presented which can be used to control colluders' strategy in collusions of size up to 3. Scattering codes can be combined with dual Hamming codes to obtain 3-secure fingerprinting codes much shorter than those resulting from Boneh-Shaw's general construction     

Use of stem cells from mismatched related donors

Mismatched haploidentical bone marrow transplantations from a related donor have been the topic of clinical and laboratory research for more than 20 years. During that time, new treatment strategies have been designed based on animal experiments, and, since our group introduced the megadose inoculum which combines T-cell-depleted bone marrow cells with a large number of granulocyte colony-stimulating factor-mobilized peripheral blood stem cells and a more intensive conditioning regimen, have done much to overcome the problems of graft-versus-host disease and graft rejection. As most patients have a full haplotype mismatched relative available, this technique means that a far greater number of patients with hematologic malignancies can be offered a T-cell-depleted transplantation as curative therapy.     

Hepatic vein thrombosis. Diagnostic and therapeutic difficulties

Budd Chiari syndrome (liver vein thrombosis) may be a diagnostic and therapeutic problem. On the basis of four different cases we review the major diagnostic and therapeutic principles involved. Imaging techniques are necessary in order to establish the diagnosis. Ultrasound examination with Duplex doppler is usually sufficient, but MR angiography is also useful. Treatment options are thrombolysis, surgery or liver transplantation. What treatment is selected will depend on the clinical situation and the prognosis.