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Wind energy is generated via the use of wind blades, turbines and generators that are deployed over a given area. To achieve a higher energy and system reliability, the wind blade and other units of the system must be designed with suitable materials. In this paper however, a computational intelligent model based on an artificial neutral network has been propose for the evaluation of the reliability of the wind turbine blade designed with the FRP material. The simulation results show that there was a reduction in the training mean square error, testing (re–training) mean square error and validation mean square error, when the number of training epochs is increased by 50% such that the minimum mean square error and maximum mean square error were 0.0011 and 0.0061, respectively. The low validation mean square error in the simulation results implies that the developed artificial neural network has a good accuracy when determining the reliability and the failure probability of the wind turbine blade.

The contractile behaviour of Triton-X 100 skinned left ventricular papillary muscle from 19 patients undergoing cardiac surgery for mitral valve stenosis: n = 6, mitral valve incompetence: n = 7, or combined mitral valve disease: n = 6 was analyzed. At supramaximal activation the "vibration induced force clamping technique" was used for isometric analysis of time course and extent of isometric postvibration force recovery. Afterloaded contractions were applied for extrapolation of the maximum shortening velocity at zero load (Vmax). The Calcium sensitivity was analysed by variation of the free EGTA-buffered Calcium concentration at a passive resting force of 2 mN at 26 degrees C. In different types of mitral valve disease the characteristics of isometric force development were unaltered in terms of maximum force development, force per square mm, Calcium sensitivity and the time course of isometric contraction after force clamping. However the capability to shorten as expressed by Vmax was reduced in mitral valve incompetence (3.87 +/- 0.37 ML/s) as compared with mitral valve stenosis (5.29 +/- 0.35 ML/s) or combined mitral valve disease (4.83 +/- 0.51 ML/s). The ratio between the inverse value of Vmax and the time constant of isometric force development after force clamping was significantly different in mitral valve incompetence as compared with other types of mitral valve disease (p < 0.0001). These data argue for the presence of different resistances against shortening in various types of mitral valve disease, due to altered cross-bridge cycling characteristics or to morphological factors.

The influence of calcium, resting force and temperature on the contractile behaviour in isolated demembranized ("skinned") pig papillary muscle fibers (n = 36) was analysed. Demembranisation excludes the influence of any membrane related processes on the contractile response as the myofilaments are in direct contact with the bathing medium. Resting force (1 mN-9 mN), temperature (22 degrees C or 32 degrees C) and pCa 7.0-4.3 were varied and the contractile response was analyzed by studying the time constant and the extent of post vibration force recovery (PVFR) of the activated preparations (the vibration method). Additional constant-load experiments and detection of sarcomere-length were carried out. There was an inverse-linear relationship between time constants of post vibration force recovery and maximum shortening velocity as estimated by constant load experiments. Resting force affected the extent of force development but not the time constant of post vibration force recovery and modulated the pCa-force relationship without altering the calcium concentration required for half-maximal activation (calcium sensitivity). In contrast lowering the bath temperature from 32 degrees C to 22 degrees C caused a significant leftward shift of the pCa-force relationship potentially due to changes of the contractile filaments' calcium sensitivity. The effect of temperature on the myocardial contractile system is of special interest as hypothermia is frequently used in cardiac surgery. Analysis of alterations of the contractile proteins' calcium sensitivity during the rewarming period of the patient may provide further insight in the pathophysiology of reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

UNLABELLED The contractile behaviour of demembranized atrial and ventricular myocardium of 7 patients transplanted for end-stage heart failure (ESHF) was analyzed. Atrial muscle specimens of patients undergoing coronary artery bypass surgery (n = 9) and pig papillary muscle were used as reference preparations (n = 9). Extreme care was taken for dissection and mounting the muscle fibres (0.3 x 6 mm) in order to keep the passive series compliance small. Calcium sensitivity, cross-bridge cycling rate (estimated by the force-clamping technique and calculation of the shortening velocity at zero load [Vmax]) and isometric force development were measured. Analysis on light- and electronmicroscopic level was carried out. RESULTS 1) Calcium sensitivity was not altered in ESHF patients; 2) the velocity of the force generating process (cross-bridge cycling rate) was normal in ventricular and reduced in atrial ESHF myocardium, 3) maximum isometric force development was reduced in ventricular, but not in atrial myocardium of ESHF patients, and 4) Vmax was significantly reduced in ventricular and atrial ESHF myocardium (p < 0.0001). Perimysial and endomysial fibrosis was present in ventricular, not in atrial myocardium of ESHF patients. CONCLUSION A normal cross-bridge cycling rate in left-ventricular ESHF myocardium combined with a decreased capability of muscle shortening indicates the presence of a resistance against shortening localized either on the cross-bridge level or/and due to intra- and pericellular fibrosis. Left-ventricular contractile dysfunction in patients with end-stage heart failure may be related to a normal contractile apparatus contracting within an abnormal intracellular or interstitial environment.