蒸氨工艺的应用与改进

介绍并分析了间接蒸氨工艺应用中出现的问题。结合生产实际对原有工艺进行了改进,使蒸氨废水指标更稳定,蒸氨工艺更符合节能环保的要求。     

Geomembrane tensions and strains resulting from differential settlement around rigid circular structures

A simplified model is presented that analyzes tensions and strains in a geomembrane. The membrane analysis is applied to circular structures subjected to differential settlement. It was found that wrinkles are induced in the geomembrane around the circular structure and the associated mechanism was investigated. An improved predictive model was developed based on the wrinkled membrane theory. The model introduced the concept of a “variable Poisson's ratio”, and allowed tensions and strains associated with wrinkles in the geomembrane to be considered. Parametric studies and a comparison between the simplified model and the improved model were performed. Limitations associated with the two models are discussed and some practical recommendations are made with regard to the control of geomembrane tensions and strains around circular structures.     

A new method for resolving the influence of circular birefringence in FBG weak pressure sensor

Ideally, there is a linear relationship between the max of PDL and pressure in FBG weak pressure sensor. However, the linear relationship has been broken down because of the cross sensitivity about the circular birefringence and pressure. In this paper, the relative PDL was proposed to solve the cross sensitivity problem. For different circular birefringences, the experimental results show the same pressure sensitivity value of 2.29 dB/(N/nm). The theoretical analysis and experimental results prove that the proposed method can solve the cross-sensitivity problem in FBG weak pressure sensor. This research can provide useful information to practical application.     

6/8极双绕组电机环流实例分析与对策

6/8极双速电机功率为53kW/23kW。因功率相差较大,故设计时采用双绕组,但产生环流使电机不能起动。文章分析了环流产生的原因并提出了解决方法。     

Comparison of open-air and semi-enclosed cultivation system for massive microalgae production in sub-tropical and temperate latitudes

This study compared open-air and semi-enclosed production system of the marine microalgae Nannochloropsis oculata in a sub-tropical region (32°S; 52°W) under uncontrolled environmental conditions. The semi-enclosed system was composed of 1.2 m³ circular tanks installed inside of a greenhouse. Water temperature was 4 °C higher in the indoor treatment than in the outdoor, mainly in winter although no difference was observed in warmer seasons. Moreover, variation in salinity was observed in the outdoor treatment due to rainfall (winter) and evaporation (spring), whereas indoor treatment experienced an increase (up to 100 PSU) due to evaporation only in warmer seasons. Light transmission was approximately 20% lower in the indoor treatment although cell densities and biomass yields were higher indoor during winter. As the temperature increased (spring) no differences were observed among treatments. In summary, partial control of temperature and salinity in the semi-enclosed system, especially during the colder and rainy season, allowed higher microalgae biomass production. Further experiments must be conducted with CO₂ addition, larger pH range and salinity control.     

Geometrically Non-Linear Rapid Heating of Temperature-Dependent Circular FGM Plates

Based on the uncoupled thermoelasticity assumptions, axisymmetric thermally induced vibrations of a circular plate made of functionally graded materials (FGMs) are analyzed. Each thermomechanical property of the circular plate is assumed to be functions of temperature and thickness coordinate. Solution of the transient one-dimensional heat conduction equation with the arbitrary type of time-dependent boundary conditions is carried out employing the central finite difference method combined with the Crank–Nicolson time marching scheme. Afterwards, with the establishment of the associated Hamilton's principle and the accountancy of the von Kármán type of geometrical non-linearity, the motion equations are obtained with the aid of the conventional multi-term Ritz method. The solution of highly coupled non-linear motion equations is obtained utilizing a hybrid iterative Newton–Raphson–Newmark scheme. After validating the developed computer code, some parametric studies are accomplished to show the influences of various involved parameters. It is shown that temperature dependency, geometrical non-linearity, plate thickness, power law index, and the type of thermal in-plane and out-of-plane mechanical boundary conditions, all affect the temporal evolution of plate characteristics.     

Use of coordinate measuring machines and digital optical machines for the geometric characterization of circumference arcs using the minimum zone method

This paper presents an optimised method for the characterization of circular features of any amplitude, which includes the capture of geometric data, by means of the use of three-coordinate measuring machine or digital optical machines with a CCD camera, and its subsequent mathematical processing. The proposed model determines the radius and the circularity error, based on the minimum zone method, and to this end it uses linear programming techniques, the Simplex programming principles and the limaçon approximation. An experimental study on ring gauges and reference disks is provided, including a comparative analysis using the Chauvenet and Grubbs filtering procedures. Last of all, an uncertainty estimation method is proposed by means of the Monte Carlo simulation. The experimental analysis carried out on ring gauges and reference disks accredit that the algorithm developed, implemented in a Matlab® environment, gives reliable results for any circumference arc considered, regardless of its amplitude.     

Evaluation of impending collapse in circular tunnels by analytical and numerical approaches

On the basis of a straightforward analytical approach which has been recently proposed by the present authors, a comparison with numerical procedures to predict plastic collapse in circular rock tunnels is reported. In fact, numerical modeling of the evolution of progressive failure leading to collapse in tunnels is a quite complicated matter and requires great care in modeling the problem and interpretating the results. In order to provide a guide to engineers facing rock limit state problems, a few examples by means of three commercial packages are presented, discussed in details and confronted with the analytical results.     

上海市长江隧道工程洞门中心坐标精确测定

根据上海市长江隧道工程贯通处洞门中心坐标测量的卖际情况，利用数学方法将空间三维的洞门钢环实测坐标拟合出三维方程，精确求取钢环中心的三维坐标。     

圆轮廓特征综合分析的探讨与测量分析系统的研究

对圆轮廓只给出单项的圆度误差评定已不能满足使用和研究的要求。为此,本文提出了圆轮廓特征分析的概念,规定了它的作用范围,并在此基础上提出了圆轮廓特征的综合分析方法,研制了测量分析系统。