Abstract: With regard to the problem that only single index has been used in assessment of reliability, a suitable comprehensive assessment method about reliability index of electromagnetic flowmeter was established, and Mean Time To First Failure(MTTFF), Mean Time Between Failure(MTBF) and equivalent failure rate(D) were selected as the standards of reliability evaluation for the electromagnetic flowmeter in this paper. Because many evaluation elements involved and failure information and evaluation indexes are fuzzy, fuzzy comprehensive evaluation based on entropy weight was introduced to quantify the qualitative evaluation indexes, and indexes weight were determined scientifically by using comprehensive evaluation obtained from combining a subjective expert’s evaluation weight with objective entropy weight. Two kinds of the domestically produced electromagnetic flowmeter were studied, the censored data obtained from the process of consumers’s use were analyzed, and fuzzy comprehensive evaluation method based on entropy weight was used to evaluate the indexes of reliability in two kinds of electromagnetic flowmeter comprehensively. The results show that the conclusion is consistent with the fact, the method can effectively solve the problem existed in current modeling, and evaluation of electromagnetic flowmeter reliability has great practical value in the application.
Abstract: ABB and SIEMENS schemes based on the voltage change rate are the existing main protection for HVDC transmission lines. But the analysis and simulation tests show that these protection schemes may be unreliable as high impedance faults or as disturbances of above 2% noisy. The paper presents a new protection scheme of traveling wave current polarity comparison for a bipolar HVDC transmission line. The traveling wave current polarity is represented by the wavelet modulus maxima (WMM) of the fault current traveling wave. The traveling wave current polarity comparison protection scheme is evaluated by PSCAD. The extensive simulation studies show that the proposed scheme is reliable to distinguish internal faults from external faults of HVDC transmission lines. And the protection scheme is immune to high impedance faults and able to accurately detect the fault line under the electromagnetic coupling circumstance.
Abstract: Objective To study the correlation between the airway dimensions from third to five generation of bronchi, and pulmonary function test(PFT) results in patients with chronic obstructive pulmonary disease(COPD) by using inspiratory and expiratory multisection computed tomography(MSCT). Materials and Methods The study included 19 patients with COPD who underwent both inspiratory and expiratory CT. For each patient, airway luminal areas and wall thickness from the third to fifth generations of RB1 and RB10 were measured. Correlations between these parameters and PFT results were evaluated. Results The correlation coefficients between airway luminal at expiratory CT and PFT results were higher than those for inspiratory CT, and improved as the airway size decreased from the third to the fifth generations. Conclusion Some parameters of airway luminal are significantly correlated with PFT. MSCT can be used to assess the pulmonary function of patients with COPD.
Abstract: According to the electromagnetic acoustic technology, an automatic system was constructed to detect the defects of steel tubes. On the basis of analyzing the principle of detecting the defects of steel tubes by the electromagnetic acoustic technology, an electromagnetic acoustic transducer was designed to transmit and receive the electromagnetic acoustic signals. The data were acquired by the high-speed data acquisition card and transferred to computer by PCI bus, and then analyzed and processed by computer. In addition, the selective frequency and amplification technology was used to process the weak received signal, which improved the anti-jamming ability of the system. Experiments on steel tubes with different diameter through-hole were performed, and the res
Abstract: This paper discusses the sustainability of the areaway-attached basement concept with the attentions focused on wind-driven single-sided natural ventilation. First, numerical simulations were performed on an areaway-attached basement with a single-sided opening. Two CFD approaches: Reynolds averaged Navier-Stokes (RANS) and large-eddy simulation (LES) were used and compared with the previous experimental results of effective ventilation rate. A good agreement between the measurement and LES model was found and RANS model tends to underestimate the ventilation rates. Furthermore, Based on LES with the inflow turbulent fluctuations, the mean airflow patterns within and around the areaway-attached basement was investigated for different wind incidence angles to examine the influences of wind direction on ventilation performances.
Abstract: How to determine a representative and economical soil sampling method that combines soil properties with advanced technologies has been an unsolved issue in soil related studies. This paper proposes a new method for soil sampling based on some measured salinity data and remote sensing images, as well as analysis of spatial distributions of soil properties in Lubotan land reclamation area in Shaanxi, China. The results showed that with the available data sets of 33 points, up to 101 unknown points can be estimated, and further interpolation of 343 points displayed spatial distribution of soil salinity in the study area, the coefficients of determination (R2) for the predicted soil salinity were 0.817, respectively. A further Kriging analysis for top soil salinity distribution in the study area showed that soil salinity has a medium degree of autocorrelation and low variability. The study in this paper may help understand the effect of soil reclamation efforts and local water management practice.
Abstract: Based on the determination method of the comprehensive domestic and international surface roughness, by the method of indoor artificial rainfall, the determination of soil surface roughness had been studied from the measurement accuracy, time-consuming and resolution. The results showed that the laser scanner method was the best to determine the surface roughness, followed by pin meter method, the roller chain meter method, and the ruler was the worst. The results of determination had the better correlation between the laser scanner method and the roller chain meter method before rainfall, however they had poor correlation after rainfall. They had the better correlation between the laser scanner method and pin meter method both before rainfall and after rainfall. And on this basis, the relationships were established among the different methods. The results provide theory basis for the further study on soil surface roughness. At the same time, it would serve for harnessing soil and water loss of the slope farmland in Loess Plateau.
Abstract: This paper presents an observer-based hybrid adaptive cerebellar model articulation controller (CMAC) with a supervisory controller for uncertain chaotic systems, in which the hybrid adaptive control composed of a direct adaptive CMAC and an indirect adaptive CMAC control is performed as the sliding mode control (SMC). The total states of the chaotic system are not assumed to be available for measurement. A state observer is used to estimate unmeasured states of the systems. The supervised control is appended to assure that the hybrid adaptive CMAC controller achieve a stable closed-loop system through Lyapunov stability theory. Finally, simulation results show that the effect of the approximation error on the tracking error can be attenuated efficiently.
Abstract: This paper presents an analysis of liquid drinks concentration using microprocessor based sensor. A prototype model based on hardware and software is used to run this analysis. The model then is tested and a few type of branded sold drinks base is analyzed on its concentration. The hardware comprises of a portable device that has been design to detect the differences between selected liquid drinks concentration. Those tested experimental drinks are Sunquick Blackcurrant, Sunquick Orange, Greenhill Rose, Greenhill Mango and Dutch Lady Full cream milk. A light dependant resistor (LDR) is used as the sensor to measure the light density through the liquid. The method has obtained the input voltage from the LDR circuit and display the concentration measurement on the liquid crystal display (LCD). Successful output has been gathered from the designing circuit. A printed circuit board (PCB) layout and programming using Basic language is developed and design in the identified hardware and software. This research has produced a data collections and statistical analysis on the identified drinks concentration. Comparison has been made and mathematical concept on the design system has been carried out.
Abstract: The automated guided vehicle (AGV) is a key component for the successful implementation of flexible manufacturing systems (FMS). AGVs are wheeled mobile robots (WMR) employed for material handling in the constantly evolving layouts of these modern factory shop floors. As such their ability to navigate autonomously is an equally important aspect to sustain an efficient manufacturing process. However, their mobility efficiency is inherently affected by the unproductive systematic and non-systematic odometry errors. Odometry errors mainly occur due to the mobility configuration of the AGV drive train and the surface characteristics the robot is interacting with. Odometry error accumulates over the distance traveled and leads to severe dead reckoning inaccuracy if the robot’s feedback control mechanism is unable to correct the error fast. This paper proposes an innovative drive train mechanism called dual planetary drive (DPD) that will minimize odometry errors without the need for complex electronic feedback control systems