Advanced Materials Research Vols. 753-755

Abstract: According to the present state that traditional regular repair methods are always adopted for mining equipment maintenance, this paper puts forward a method of installing various sensors on the equipment which are combined with computer and signal analysis technology so as to realize on-line monitoring, fault prewarning, and remote release. This paper analyses the common faults of mine ventilator and their characteristics, selects the vibration sensor and its mounting points based on the characteristics of the fault signal, selects the signal acquisition cards based on equipment operating conditions and analysis parameters accuracy, builds up the hardware and software platform, completes the design of system function module and data flow, and achieves modularization programming for the whole software system by combining labVIEW and database. This system realizes the condition-based equipment maintenance so that informatization and automation can be achieved in equipment management.

Abstract: The paper puts forward a method of ventilator running state prediction which is based on EMD and Neural Network, which aims at ventilators non-stationary vibration signals. First of all, vibration data are decomposed into eight intrinsic mode signals and one residual quantity by EMD. Then Neural Network is adopted to predict the decomposition components and reconstruct them. Finally, the final prediction results are achieved. In this paper, the ventilator vibration signals of Tangshan Iron and Steel Group Coking Plant from March 1, 2012 to July 1, 2012 are used as the research data. Comparative study method is adopted to compare this prediction method with direct Neural Network prediction in terms of results, which shows that this method has better accuracy.

Abstract: Error detection is relatively a new field of Software level control. A Software Developer always aims to produce good level software with a few errors. Good level of software is correlated with the number of errors as well as it is limited by time. So, error detection is very important in the field of Software level and software stability. This paper gives you a explaining about software error detection. It describes the key areas of software error detection practice, and emphasizes some key open problems for the future.

Abstract: For indoor location estimation based on Wi-Fi fingerprinting, how to reduce localization effort while maintaining high location estimate accuracy is of critical concern. The paper introduces a new approach Reward and Penalty Localization (RP-Loc) algorithm, which extends the classic WKNN Localization algorithm. The parameter of observable Access Point (AP) occurrence rate is added into the fingerprint database in the offline training phrase to increase the increase the anti-interference ability. The experimental results prove that the RP-Loc algorithm exhibits superior performance in terms of location accuracy and robustness.

Abstract: A method for analyzing the value of cepstrum without taking the logarithm is proposed. The bottom of abscissa of cepstrum is cycle of power spectrum.Ordinate of the cepstrum can identify how many lines in the sideband of power spectrum without logarithmic.Application to fault diagnosis of the test bench and the gearbox is successfully, and thus significant results are achieved.

Abstract: This Paper studied the typical PD in GIS by ultrasonic method. A GIS PD simulating and testing system is established, including a PD simulating system, an ultrasonic detecting system and a conventional pulse current method measurement system. The thesis focuses on four typical kinds of PD signals in GIS, including metal particles, bad contacts on high and grounding potential conductor, the protrusion on the high potential conductor. The statistics characteristics are obtained which include N-Φ spectrogram (relationship between discharge frequency and discharge phase Spectrogram) and Umax-Φ spectrogram (relationship between discharge amplitude and discharge phase Spectrogram). Experimental results show that low-frequency ultrasonic sensors can detect this four PD signals， signal spectra analysis shows that ultrasonic signals of different statistical model are with different characteristics. The results provide test data for the pattern recognition of Partial Discharge in GIS.

Abstract: Hypotension after spinal anesthesia for elective cesarean delivery may be harmful. This article first proposed pulse transit time variability (PTTV) analysis could be applied in the preoperative assessment of its risk. 42 patients were classified into groups of Mild, Moderate and Severe. Frequency domain analysis was performed on the day before surgery using autoregressive model. We divided the frequency band according to the troughs and extracted relevant parameters of power spectrum, while differences between groups were evaluated by t-test. The results indicating significant differences are presented in PR5, PR1/PR5, PR3/PR5 and PR4/PR5, with their discriminant accuracy on the 42 patients reaching 80.77% in low-BP group and 75% in norm-BP group. We conclude PTTV analysis can help predict the risk of hypotension on the day before surgery and the physiological mechanism is mainly due to parasympathetic regulation.

Abstract: The ball mills, which have great energy consumption, are commonly used in coal-fired power plant. The key to reduce their energy consumption is to determine the best ball loading, the optimum gradation and the complement parameters. The premise of determining these parameters is to give the balls wear law. The wear matrix model, which determines the balls probability distribution through their diameters, is one of the practice methods to determine the balls attrition rule. This study assessed the wear law through the change of balls weight, determines the program feasibility and the test time through the test of a ball mill.

Abstract: To the inconvenience problem of laying the cable, a new remote monitoring system for power based on wireless communication is designed. The overall structure of system is put forward to bring the design method of the remote terminal unit which is the key of monitoring system. Adopting the commercial wireless serial data transfer radio to realize the wireless communication between center RTU or computer and remote field RTU. According to design the multiple control modes (including: remote manual control, remote automatic control, and local control) to introduce the application of system and indicate that it is satisfied to monitor remote field power in the aerospace experiment tasks.

Abstract: Contamination of groundwater and soil by petroleum hydrocarbons is a widespread environmental problem. In order to quantify the potential of natural attenuation of groundwater at a petroleum contaminated site. The total petroleum hydrocarbons (TPH) concentrations of 11 rounds were collected during the 1 year monitoring period, and the mass flux technique is used to calculate the attenuation rates. The calculated attenuation rates are between 0.0046-0.0064d^-1, which indicating the time to achieve the remediation goal for the contamination site is possible within 3 years by natural attenuation alone.