Applied Mechanics and Materials Vols. 239-240

Abstract: The thermocouple is extremely wide application in temperature measurement. The active sensor has the advantages of simple structure, wide measuring range, high precision, signal stability and other advantages and is widely used in the detection of furnace and pipeline temperature. The author analyzes the theory of measurement of thermocouple, and put forward a kind of originality of thought. According to this idea, the author derives several laws of thermocouple, and finds that a simple estimation method. Finally, some of the common thermocouple method measurement results are given.

Abstract: One measurement of rotation angle about rotating object was proposed, it can realize precise and non-contact measurement. This measurement was executed as follow: firstly, select one image that it has abundant information, and the object which need rotation was pasted by this image. Secondly, when this object is begin to rotation, use CCD to collect the external images of the object before and after rotation respectively. Lastly, convert these two collected images from Descartes coordinate to polar coordinate, then calculate these two images in polar coordinate with phase correlation. The rotated angle was found by these steps. The result of this measurement experiment shows that this method can measure the rotated angle correctly. So this measurement method is worth to research and apply according to the theory and the experiment.

Abstract: Polygon ranging-based space coordinate measurement network, which has high measurement accuracy and simple structure, is suitable for large-scale metrology. In practice, the measurement network should be constructed flexibly according to coverage and shape and measurement accuracy of different measurand. Based on this, a universal analysis model of structural optimization is proposed. The relation between structural parameters (amount and layout of measurement base stations) and distribution of measurement accuracy of the measurement network are researched on the model. The model can provide theoretic basis for optimized and flexible design of the measurement network. A case is used to illustrate this model. The results verify that the module can be used for scientifically establishing measurement system of ultra-large size, and also preliminarily simulating and optimally designing the being adopted measurement network and measurement method for meeting requirements of size and measurement accuracy (including global and local accuracy) of different work pieces.

Abstract: Roller kiln is a kind of advanced fast sintering kiln. In production process of roller kiln, materials sintering of burning zone is the key working procedure which affects product quality directly. Hence, the temperature detection process of burning zone became the key link in roller kiln control system. This paper proposed a kind of fusion method of both temperature point detection and flame image recognition of imitating ‘artificial-look-fire’. Flame image processing-based temperature detection scheme was also given. In the scheme, expert system fuses temperature data detected by the thermocouple with flame image data of burning zone detected by CCD so as to obtain the actual temperature of burning zone. The method proposed greatly improves the temperature detection precision of burning zone working conditions. The experimental results show that the proposed method is feasible and effective.

Abstract: This work presents an analysis of atmospheric electrostatic field (EF) networking using radar and sounding data base on a quasi-normal charge distribution model in isolated storm cells. The charge distribution parameters of the thundercloud are first estimated and inversed with the model, and then the networked EF of the ground can be recalculated using the obtained parameters. The method was used to analyze three isolated thunderstorms that passed through the experiment site in 2009. It was found that the EF networking and the charge distribution were concordant with the location of lightning and radar echo. It is revealed that the method for EF networking using radar and sounding data is feasible. It was also found out that the charge structures of three thunderstorms were similar, i.e., the charge structure was dipole in the development, tripole in the mature stage and dipole in the extinct stage. The charge structures at different stages, charge space-distribution around cloud-ground (CG) lightning occurrence may be conducive for electrostatic characteristics research and lightning forecasting.

Abstract: As the technology of sensor network advances, wearable health monitoring becomes feasible. Here we present a context-aware monitoring system for cardiac health, which consists of three modules: signal acquisition for physiological signal as well as context information; processing, analysis and interpretation of signal modality as well as fusion of context to generate cardiac health indices; interface for human-machine interaction. Both captured original data and analysis results are stored in an SD card for further processing in the server. The system works continuously for 24 hours. The proposed cardiac health indices can be applied for health status monitoring and early prediction of cardiovascular disease.

Abstract: Radial velocity (RV) of a star caused by Doppler shift could be easily measured by cross-correlated it’s spectrum with a serial template. Generally, the RV error of a spectrum always is given by the widths of the cross-correlation function of the target spectrum and related template spectrum. RV error comes from many factors, causing from instruments, observation weather, etc.. In this paper, simulation with different types of stellar spectra, which has different temperature, is implemented. The results show that there is an internal error which is not generated by the calculation steps for a given resolution step, for example, 5km/s error exists in the cross-correlation based RV measurement method for resolution about R~2000. The simulation also proves that this error could not be avoided for any type of stars.

Abstract: Objective To assess the three dimensional (3D) accuracy of deciduous tooth surface model reconstruction from cone-beam CT(CBCT) scans using image superimposition method. Methods 14 sound extracted human deciduous teeth were scanned by micro-CT and CBCT scanner. The digital tooth models reconstructed from CBCT scans were superimposed onto the standard model from micro-CT scans respectively. Distribution patterns of shape discrepancy were presented using histogram, as well as shown in different colors on the superimposed images. The voluminal discrepancy versus the volume of the standard image (RVD/VS) were calculated and analyzed, using t test. Results There was no statistically significant difference between deciduous anterior teeth and molars(P>0.05). The mean RVD/VS of digital tooth images obtained by CBCT scans was 3.932±4.038%, and significant difference were found (P<0.01), compared with the standard tooth model from micro-CT. Marked by different colors, the superimposed images could give visualized information on the dimensions and distribution patterns of discrepancies. Histogram gave the statistical description about the numbers and magnitude of the discrepancies. Conclusions The superimposition method and the concept of RVD/VS are recommended for 3D accuracy evaluation. CBCT is of high accuracy for tooth modeling and suits for clinical and research purpose.

Abstract: Using triaxial tests of rock mechanics on stress testing instrument to analyze the results of its parameters, and obstained the the region that was consistent with the transformation between static and dynamic rock mechanics, the relationship between formation pore pressure and rock mechanical parameters, the pressure profile in the basis of rock mechanics parameters, etc. Combination of logging information and data, the method was identified which was in line with the use of rock mechanics parameters to strike a formation pressure. Using this method, I have analysised the formation pressure profiles of several wells in a block, and established the corresponding formation pressure detection section and the section of rock mechanics. The tested pressure and the measured pressure were compared more than 85% accuracy.

Abstract: Life parameters signal has characteristics of extremely low frequency, low signal-to-noise ratio, and the easy submerged in strong clutter noises. The method for detecting life signal based on filter bank and high order statistics is presented, in which neither the Gaussian supposition of the observed signal, nor a prior information about the waveform and arrival time of the observed signal is necessary. The principle of method is to separate the spectrum of input signal into many narrow frequency bands, whose Sub-band signal is followed by a short-time estimation of higher-order statistics so as to suppress Gaussian noises. Simulated results show that the method not only can completely descript life signals in the time-frequency domain, but improve the signal-to-noise ratio and the ability of detecting algorithm. Moreover, the method is effective and practical.