Advanced Materials Research Vols. 821-822

Abstract: In order to improve the safety and stability of dredger crane (DC), three dimensional finite element models for the DC were established. By applied loads and boundary conditions, the area of stress concentrations, the axis force of jib cylinder and the reaction force of the king structure was obtained under four typical working conditions. Meanwhile, the related theoretical calculations were accomplished to comparing finite element results and at last some suggestions were given. The conclusions can provide a theoretical reference for the further structure design and optimization of DC.

Abstract: In view of orthogonal cutting, finite element simulation geometry is built. the friction model, thermal conduction model and chip separation model are established between chip and tool using Abaqus which is a finite element analysis software. Through a specific example, two-dimensional finite element model have been established, simulating the cutting process stress distribution of the work piece surface is also obtained during processing. While simulation analyzes the relationship between the rake angle and shear angle, the results of simulation and experiment are basically the same, thus further verify the credibility of Abaqus simulation results on orthogonal cutting, and the feasible is also proved of obtaining cutting data by the use of Abaqus simulation cutting process.

Abstract: When gas kick Occurs during drilling, because of pressure, temperature, coefficient of gas compressibility and other parameters changing continuously, gas will slip along the borehole and also accompany expansion some extent, and bottom hole differential pressure increases, resulting in the amount of invasion gas increasing continuously until blowout. The procedure of gas kick till blowout in the borehole is transient gas-liquid two-phase flow, studying on The development of gas-liquid two-phase flow parameters variation characteristics and bottom hole pressure variation characteristics plays an significant role to understand blowout occurrence and development characteristics. This paper using methane-mud as the circulating medium simulates the procedure of gas kick till blowout near the bottom under the condition which is almost the onsite drilling process, Analyzing the flow pattern, bottom hole pressure variation characteristics, and velocity distribution under the different stages of gas kick, different influx, and obtained an initial understanding.

Abstract: Drilling string lateral vibration is a severe damage,which is influenced by many complex factors. This paper makes a theoretical analysis of the drilling string lateral vibration frequency caused by drilling fluid flow velocity inside and outside the drilling string, which supplies some evidence for calculating rotation speed of rotary table and reduces the times of drill string resonance. The influence of drilling fluid flow velocity inside the drilling string on lateral vibration frequency is analyzed by Euler method. Besides,through the use of mechanical analysis method and the introduction of additional mass coefficient. A differential equation of drilling string lateral vibration with the consideration of drilling fluid flow velocity inside and outside the drilling string is built up, and a mathematical model of drilling string lateral vibration under the influence of drilling fluid flow velocity is obtained. Field applications indicate that this model is in agreement with the field condition. Key words: mass coefficient;differential equation; drilling fluid flow velocity; lateral vibration frequency;

Abstract: The complexity and depth of drilling are increasing constantly, so an advanced well control technology is required, and early kick detection as the key to well control is very important. Rapid and accurate kick detection helps to eliminate kick and rebalance the wellbore pressure, which not only improves drilling operation efficiency, but also reduces the probability of blowout, well collapse and other accidents. Accordingly, this paper has analyzed the applicable conditions, advantages and shortcomings, and field applications of the existing kick detection technology including mud pit surface detection, delta flow method, liquid level monitoring in the wellbore detection, gas invasion detection, kick detection while drilling, multi-parameter comprehensive detection system and comprehensive logging detection and analysis technology, and proposed the research trends and application suggestions of kick detection technology.

Abstract: Nowadays, wireless sensor networks (WSN) focus on sounds and images and other complex patterns such as data collection, processing, transmission, integration and reconstruction. In order to support these types of data, network node processors need the higher requirements. The embedded multi-core processors are able to play a great role. For improving the efficiency of multi core processing node, a cache allocation algorithm which provides suitable cache to parallel tasks is proposed. By experiment verification, the proposed algorithm achieves higher performance than that adopting conventional LRU scheduling algorithm which improves the WSN performance and utilization effectively.

Abstract: In the paper, the specific issues is discussed whether or not the points on the convergence circle are the singular point of a sum function of a class of power series. Whats more, the relationship between divergence of the power series on the convergence circle and the pole of its function on the convergence circle is explored. And a new result is obtained that there exists the pole of its function on the convergence circle, the power series has the characteristic of everywhere divergence on the convergence circle.

Abstract: In this paper a algorithm of digital image watermark based on wavelet bit plane is introduced, and the original image is not required for detecting the watermarking. The digital watermark is embedded by changing information of some bit planes in DWT images at different resolutions. The watermark can be extracted on the difference bit plane values of subimages of the decomposed watermarked image which is then mapped to an image with a few shades of gray. Experimental results show that the watermark is robust to several signal processing techniques, including JPEG compression and some image processing operations

Abstract: In the process of the Installation and quality testing of the slewing ring , In connection withinjuries for workers installing ball and inconvenience for quality testing of slewing ring , we establish a slewing bearing assembly and quality inspection system based on virtual instrument .with labview interface , the system goes to control the stepper motor forward, reverse , indexing stepping and stopping , in order to stimulate the slewing ring to rotate , so that workers install ball ; Meanwhile, wo can go to collect, display, store the information of the slewing ring , generate reports, and query historical data .

Abstract: The paper introduces the structure and working principle of coreless disc tensioner, using Euler tension formula to calculate the output tension, analyzing the yarn diameterin ideal and actual situations and getting amplification characteristics of the disc tensioner against tension fluctuation. It is found that the tension disc will not expand the tension fluctuation amplitude in ideal condition, and its own performance has certain compensation for the tension fluctuation, which provides a the oretical basis for the design of the coreless disc tensioner and its wide application.