Applied Mechanics and Materials Vol. 367

Abstract: Some of the heart valve diseases can be treated by surgical replacement with either a mechanical or bioprosthetic heart valve (BHV). Recently, tissue-engineered heart valves (TEHVs) have been proposed to be the ultimate solution for treating valvular heart disease. In order to improve the durability and design of artificial heart valves, recent studies have focused on quantifying the biomechanical interaction between the organ, tissue, and cellular –level components in native heart valves. Such data is considered fundamental to designing improved BHVs. Mechanical communication from the larger scales affects active biomechanical processes. For instance any organ-scale motion deforms the tissue, which in turn deforms the interstitial cells (ICs). Therefore, a multiscale solution is required to study the behavior of human aortic valve and to predict local cell deformations. The proposed multiscale finite element approach takes into account large deformations and nonlinear anisotropic hyperelastic material models. In this simulation, the organ scale motion is computed, from which the tissue scale deformation will be extracted. Similarly, the tissue deformation will be transformed into the cell scale. Finally, each simulation is verified against a number of experimental measures.

Abstract: In this paper, a novel method is proposed by combining of radar clinometry and interferometry to improve the accuracy of digital elevation model (DEM) reconstruction. In synthetic aperture radar (SAR) signal processing, the interferometry method uses a couple of high-coherence SAR complex images and the clinometry method uses only one. On one hand, interferometry-derived DEM is much more accurate in regions of higher coherence than the clinometry one. However, in regions of lower coherence, some pronounced errors are produced with the interferometry method due to phase filtering and unwrapping problems. On the other hand, the clinometry method can produce a more robust DEM result by using the intensity of SAR image. Therefore the clinometry-and interferometry-derived DEM is fused by introducing a user-defined weighting factor, where in regions of higher coherence, the DEM results with the interferometry method are remained, and in regions of lower coherence, the interferometry-derived DEM is updated with the clinometry-derived one. Finally, the experimental results with Envisat data show the effectiveness of our approach.

Abstract: A self-adaptation method for natural-coordinate systems is proposed, in order to automate the selection of natural coordinates for each rigid element of a multibody system. The four-step method includes: First, find out all empty positions, which come from the feature points or vectors of the joints attached to the element, and give equal weight to them; second, delete redundant empty positions and add their weight to the unique one; third, select at most four empty positions which have a maximum total weight and can be occupied by a natural-coordinate system at the same time; fourth, the standard natural-coordinate system on the element can adapt itself to the selected empty positions, leading to an actual natural-coordinate system, which contains twelve rational natural coordinates for the element. The implementation of the method has been achieved on a multibody dynamics and motion analysis platform, InteDyna, with the result that modeling efficiency is enhanced and model quality improved.

Abstract: The soil water deficit and strong transpiration can give rise to the phenomenon of plant water stress. Because of the water stress produces the fracture of the water column in conduits, and the fracture is the reflection of energy release which can be detected by the ultrasonic acoustic emissions (UAEs) technology. In order to avoid background noise interference, the UAEs detecting frequency is between 100K Hz and 1 MHz. The PCI-2 data acquisition (DAQ) card and R15 sensors are used to improve the precision of UAEs detection. When the water stress and dehydration gets heavier, the UAEs get higher. Use the tomato plant data with the empirical deduction under the modern greenhouse conditions, the relationships among UAEs, transpiration and UAEs signal strength is described by curve. The UAEs signals occur generally from 5:00~7:00 am, and stop after 20:00 at night. In the daytime, when the plant body water storage is few, and transpiration is strong, the UAEs occur two peaks, called the “Twin Peaks Area” (TPA). In the different conditions of soil water content status and environmental factors, the TPA occur time will be advance or lag, which is generally in the range of 8:00~15:00. An acoustic emission event maybe produces several UAEs counts, while the UAEs counts have a correspondence with the UAEs signal strength. It is better to use UAEs technique to diagnose the plant water status and carry out automatic and precise irrigation for the plant and to improve the effect of Water-saving irrigation.

Abstract: The precise measure of atmospheric refractive index is one of the key factors which leads a guarantee of accurate estimate in the atmospheric refraction error margin and the forecast of atmosphere wave in the electronics systems, such as radar and correspondence...etc.. The error of 59 radiosonde which are in common used to measure atmospheric refractive refraction index is bigger, the microwave refract meter which has high accuracy also has the characteristics of high expenses, big weight of the instrument, those all bring very big restriction to engineering physically applications. For this cause, according to the principle that the variety of atmospheric refractive index brings frequency to the LC shock loop which composed by fixed inductance and air capacitor, this paper designs a light capacitance type refract meter which is use low temperature degree coefficient air capacitor for measure of sensitive component. Experiment validated: The precision of light capacitance type refract meter is more better than 59 radiosonde in measuring atmospheric refractive index, and it has no space-time measure error when sending out the temperature, wet, pressure respectively which is common find in 59 radiosonde, and it has advantages like light weight, small lag coefficient etc.

Abstract: This paper is concerned with the structural stability problem involving uncertain-but-bounded parameters, specified as bounds on these parameters. This produces interval stand and geometry stiffness matrices, and the problem is transformed into a interval buckling eigenvalue problem in interval mathematics. The perturbation method is proposed to determine the lower and upper bounds on the buckling eigenvalues and due to uncertain-but-bounded parameters. Moreover, the critical load of the uncertain structure can be obtained. The effectiveness of the presented method was demonstrated by comparison with conventional stability theory, using a typical numerical example.

Abstract: The manual work or Excel based material mixing ratio method has low computer application level and lays high computer capacity on design construction workers. It is difficult to obtain the most optimal technical and economic program from a number of optional programs. The paper built mathematical model of materials mixing ratio based on genetic and identified constraint conditions. Data pre-processing was performed according to the constructed model. According to specific circus of material mixing ratio calculation, the fitness function and various operators were designed and parameters of model were also configured. At the same time of meeting requirements of project quality, multiple target optimizations were considered to give new model and constraints. The highway construction mixing materials ratio calculation based on genetic algorithm achieves expected goal and improve accuracy and efficiency of operations.

Abstract: In this paper the Real Interpolation Method is offered for the solution of systems Identification problem. The Real Interpolation Method allows to create a sufficiently cost-effective algorithmic basis and to solve all complex of Identification problems. It is based on use of a special case of the Laplace transformation, when the complex variable s =δ + jω is degenerated to real value δ.

Abstract: According to the world health organization, major depressive disorder (MDD) is considered as the fourth main cause of death and premature weakness in the whole world. Abnormality in the hormones and neurotransmitters level is the one of the main factors which may result in this disorder. In this article melatonin is chosen among these hormones, which is the most implicated to control sleep and depression. Because the measurement of melatonin is crucial important, the fuzzy logic approach as the mathematical method is utilized to making melatonin behavior model. In this paper, two effective factors on melatonin are modeled by fuzzy logic. This model is only a part of our project which is performed for modeling of the major depression.

Abstract: The deep sea magnetic field detection is influenced by the environment of marine and the platform, the influence of the platform is mainly caused by platform rotation. The variation of the geomagnetic fields three-components caused by different directions of the platform rotation are compared by using the World Magnetic Model WMM2010.The results show that the changes of the three-components of the Earth's magnetic field caused by the platform rotation can not be ignored. So the measured results of the deep sea geomagnetic field detection should be compensated. The conclusion can be used for automatic correction of the deep sea magnetic field observation platform.