Applied Mechanics and Materials Vols. 121-126

Abstract: With Ilmenite residues as raw material, the inorganic high molecular weigh coagulant is prepared by orthogonal experiment method. It shows that optimum synthesis conditions are: the polymerization temperature being 50°C, the dosage of acid being 20ml, the polymerization time being 2h,and the dosage of oxidant being 8ml. The structure and morphology characteristics are analyzed by FT-IR and SEM. The application of the coagulants in printing and dyeing wastewater treatment is explored.The coagulation experiment results show that the removals of chroma and COD are affected by preparation conditions.

Abstract: With the implementation of crash-toughened adhesives in automotive industry, adhesive bonding has become one effective joining technology instead of resistance spot welding especially for AHSS materials because of its better fatigue performance and greater flexibility. However, while chisel test has been widely used for resistance weld inspection, no practical inspection method is available for adhesive bond discrepancies identification. The inspection method we need for use in a high-volume, low-cost production environment should be fast, convenient, nondestructive, cost-effective, and able to effectively assure some minimum acceptable level of joint quality. The method we finally conducted was based on the weld-bonding process of different adhesive bonding joints by acquiring and analyzing the dynamic welding parameters’ signal curves such as the electrode displacement and dynamic resistance from different sensors installed onto the welding gun. Based on the integrated inspection system, lots of experiments and analysis showed that this inspection method is basically feasible, that is, it could identify different adhesive bond discrepancies qualitatively and accurately. Especially, the on-line inspection is conducted before the complete curing of joints in paint shop. If the inspection results are nonideal and some discrepancies are detected, the further repairing work is much easier and cost-effective. So the inspection method has a good potential especially applied in production line. The findings in this study provide the guidelines for using adhesive bonding AHSS materials in automotive industry.

Abstract: In the present investigation four kinds of lexical diversity measurement have been applied to the sets of word chunks with monotone increasing size. The computational experiment with corpus processing and statistical test has been conducted to find out the most effective lexical diversity measurement in evaluating a small-sized corpus of 350~550 words, and the result shows that D-estimate is the most appropriate among the four lexical diversity measurements which are considered in this research. Also D-estimate shows more stable results than other measurements when the number of words varies between texts.

Abstract: Multi-layered unconsolidated sandstone gas reservoir is featured by unconsolidated lithology, interbeded gas-water zones and active edge water. Irrational production proration will lead to water breakthrough and sand inflow(AOF) is already incompetent in solving problems nowadays. Based on multipoint well test deliverability analysis, production data dynamic analysis, single well controlled reserves and critical situation of inflow calculation, and combining the calculation of minimum liquid hold-up gas rate an maximum erosion gas rate, meanwhile considering balanced gas recovery factor, balanced pressure drop, safe sand inflow and safe liquid hold-up, the multi-factor production plan has been set up, which is improved and adjusted by integrating water influx performance and years of stable production, through gas reservoir numerical simulation. A scientific and rational production proration pattern particularly for this type of gas reservoir has been determined. The reservoir simulation results of case study show that the water production in gas well can be controlled and the gas reservoir sustained stable production can last more than 1.3 year.

Abstract: Globoidal continuous cam with ball is a new type of transmission mechanism which can realize rolling instead of sliding. By designing the double-circular arc raceway and reforming ball seats of the indexing plate, energy loss caused by friction in the meshing movement can be decreased greatly. In this paper, firstly, the raceway is designed and the integral structure is presented. Then, the contact characteristic between raceway and steel balls is further studied based on Hertz theory; the influence of structural parameter to contact stress is discussed and methods for enhancing the load capacity of cam mechanism are proposed. Finally, the load distribution model of the ball seat is established through Stribeck load distribution theory, the meshing characteristic between ball and the ball seat is investigated. This research provides theoretical basis for the design, manufacturing and experimental study of globoidal continuous cam with ball.

Abstract: With the application scale and area of the building PV power station continuous extension, data transmission and monitoring management of the building PV power station have become increasingly important.This paper introduces a kind of data delivering and distributed monitoring management system of the building PV power station based on ZigBee wireless network,this system has information transmission modules based on ZigBee wireless network, region monitoring and magement module and remote access module. ZigBee wireless network could deliver datas of the building PV power station to the center of region monitoring and management system,ultimately,the datas were deposited in the database of region monitoring and management system,The Electricity Regulatory Office and The Power Company used remote transmission and monitoring system by remote access system on the Internet, to access data reports of the building PV power station in the database of region monitoring and magement system.System test results can carry out the building PV power station’s data transmission, monitoring system’s data management and remote access by the Internet.

Abstract: This paper reviews shearography and its applications for testing of aircraft composite structures and honeycomb-based specimen. Shearography is a laser-based interferometry in conjunction with the digital imaging processing technique for full-field measurement of surface deformation. It reveals defects in an object by looking for defect-induced deformation anomalies. It does not require special vibration isolation, and with the development of a small and mobile measuring device (portable inspection system), it can be employed easily in field/factory environments.

Abstract: In this paper, a novel method is investigated to detect short-circuit fault signal transmission lines in strong noise environment based on discrete wavelet transform theory. Simulation results show that the method can accurately determine the fault position, can effectively analyze the non-stationary signal and be suitable for transmission line fault occurred after transient signal detection. Furthermore, it can effectively eliminate noise effects of fault signal so as to realize the transmission lines of accurate fault.

Abstract: This paper discusses the principle and method of Double-Crossed Step-Down-Stress Accelerated Life Testing (DCSDS-ALT) for pneumatic cylinders. As to pneumatic cylinder, the step-down-stress testing failure physics can be described as cumulative degradation model. Temperature and frequency are normally chosen as the test stresses. The failure data obtained under DCSDS-ALT testing steps can be converted to those under constant stress testing. And the reliability specifications can be derived accordingly. To compare Double-stress ALTs with traditional constant stress testing shows Double-stress ALTs can meet the accuracy demand. The 5% of average lifetime estimation error and 1.85% of the characteristic lifetime error are very satisfying for pneumatic industrial lifetime prediction.

Abstract: Combined with partial dynamic threshold MOSFET connection scheme, a high density 7T subthreshold SRAM bitcell operating at supply voltage of 200 mV is proposed in this paper. Dual write and single read ensures high read static noise margin of the SRAM bitcell without expense of writability degradation. The 7T SRAM exhibits robust efficiency, making the design less vulnerable to process variation. Compared to the referenced 6T and the 8T SRAM bitcell, the proposed bitcell has four aspects of improvement: (1) 5.1% and 6.1% larger hold margin, (2) 80.6% and 85.5% of standard deviation, (3) 50% and 18% reduction of area (at 200 mV), and (4) 16X and 32X bitcells per bitline. To our best knowledge, the area penalty of proposed SRAM is the smallest with robustness and functionality of subthreshold SRAM achieved.