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Slender flexible structures are vulnerable to vibrations under wind loads. The dynamic model of a frame-like structure is obtained by finite element approximation in this paper and used further for the design of an active control mechanism. The behavior of the structure is described by simplified linear equations. A linear quadratic regulator and an H-2 optimal control method are used for the suppression of the extended vibration effects. Structured uncertainties are considered to reflect the errors between the model and the reality. To accommodate directly the plant uncertainties and to obtain a best possible performance in the face of uncertainties a robust H., optimal control for active control structure is used. The two latter robust controllers take into account as well incompleteness of the measured information, a fact that cannot be neglected in civil engineering, and lead to applicable designs of smart structures. The numerical simulation shows that vibrations can be suppressed by means of the proposed methods. (c) 2006 Elsevier Ltd. All rights reserved. Journal of Wind Engineering and Industrial Aerodynamics

This paper presents a layerwise modeling approach for smart piezoelectric beams and applications. The theoretical development is extended to a finite element discretization. The model is applicable for integration with various optimal control schemes and used in the design of smart structures. Moreover it allows for the investigation of delamination and interlayer damage models, their effects on the structural control as well as the design of robust control schemes and damage identification problems. International Journal for Numerical Methods in Engineering

Summarization: This paper presents a study of the implications of using auxetic materials in the design of smart structures. By using auxetic materials as core and piezoelectric actuators as face layers to provide control forces, the problem of the shape control of sandwich beams is analyzed under loading conditions. The mechanical model is based on the shear deformable theory for beams and the linear theory of piezo- electricity. The numerical solution of the model is based on superconvergent (locking-free) finite ele- ments for the beam theory, using Hamilton's principle. The optimal voltages of the piezo-actuators for shape control of a cantilever beams with classical and auxetic material are determined by using a genetic optimization procedure. Related numerical solutions of static problems demonstrate the role of auxetic material in the deformation, shape control and stress distribution of the beam and related two- dimensional composite elastic structures. Παρουσιάστηκε στο: Computational Methods in Science and Technology

A study was undertaken to determine whether blue fluorescent light might affect the sister chromatid exchange (SCE) frequency of peripheral lymphocytes in icteric newborns undergoing continuous phototherapy treatment (72 h). Also, the potential preventive effect of vitamin E on SCE frequency was studied in a subgroup of 11 preterm and 9 fullterm newborns after daily administration of vitamin E (46.44 mumol/kg/d, im). The results revealed that only the preterm icteric newborns showed an increase in mean SCE frequency of peripheral lymphocytes after phototherapy (9%, p = 0.02), but in no case did the highest SCEs/cell ratio exceed the normal values. No correlation was found between the average SCE rate and birth weight, gestational age or bilirubin levels. Also, no difference in SCEs was observed between newborns treated or untreated with vitamin E.

53 mother-neonate couples, of different gestational ages, were studied for PGF2α levels in the mother’s blood at the beginning of the first stage of labor and in the umbilical cord blood. PGF2α levels were found to be increased in all neonates compared to their mothers and in the blood of the mothers of prematures compared to the mothers of the post-mature babies. No correlation could be found between the gestational age of the neonate and the umbilical cord levels of PGF2α. © 1977 S. Karger AG, Basel.

The serum vitamin E levels of 11 full-term and 10 premature infants, jaundiced and subjected to phototherapy, were measured and compared with 9 premature and 10 full-term jaundiced control infants. No differences were observed before or after phototherapy or 1 week after stopping it. The same negative results were noted in the two groups of infants regarding the values of microhematocrit, Hb and reticulocytes.

The etiological correlations of congenital heart diseases to antenatal exposure of pregnant women to sex hormones were studied retrospectively. Of a total of 15,535 women who delivered between the years 1975-1977, 91 had babies with congenital heart disease (frequency 5.8%‰). From these babies 11 were born to 559 mothers who had taken during pregnancy hormones of the estrogen-progesterone type (frequency 19%‰). The remaining 80 babies were born to 14,976 mothers who had not taken such hormones (frquency 5%‰). The main reason for having been given hormones were: bleeding of the first trimester in 80%, and the pregnancy test in 20%. Both groups of mothers had the same possibility for being affected by factors causing congenital heart diseases. An attempt is made to correlate the structure of the hormones given, the cause and time of the administration, the outcome of the newborn, and the type of heart disease.

The histological specimens of the pancreas of 33 newborn jaundiced infants were examined and compared to 35 controls. In 4 babies the jaundice was due to Rhesus incompatibility, in 8 to ABO incompatibility, in 13 to G-6-PD deficiency and in 8 the etiology of jaundice could not be ascertained. The Langerhans’ islets were found to be hyperplastic not only in the 4 infants, whose severe jaundice was due to Rhesus incompatibility, but, to a lesser degree, in the majority of the other jaundiced infants’ pancreas as well. The surface of the Langer-hans’ islets was well correlated with the highest bilirubin level in all groups of jaundiced infants. © 1973 S. Karger AG, Basel.