Densities and Viscosities of Oleic Acid at Atmospheric Pressure

The densities of oleic acid were measured over the temperature range from (293 to 459) K at atmospheric pressure using a densimeter based on the modified hydrostatic weighing method. The dynamic viscosities of the same oleic acid sample were measured using a capillary viscometer (VPZ-2 m) in the range from (293 to 363) K at atmospheric pressure. The combined expanded uncertainty of the density, atmospheric pressure, viscosity, and temperature measurements at the 95% confidence level with a coverage factor of k = 2 is estimated to be 0.15%, 1.0%, 3.5%, and 15 mK, respectively. The values of uncertainty for density and viscosity include the effects of purity and calibration (total expanded uncertainty). These experimental data were used to develop wide-range correlations for the density and viscosity based on theoretically confirmed Arrhenius–Andrade and Vogel-Tamman-Fulcher (VTF) models. The value of the glass temperature ( T _g= 179.78 K.) for the oleic acid was estimated using the VTF parameters derived from the present viscosity measurements. To additionally validate the reliability of the measured density data, the same oleic acid samples were measured using the pycnometric method. The present study showed that the densities measured using the modified hydrostatic weighing densimeter (HWD) agree with the values obtained using the pycnometric method within 0.09% for Sample 1 and 0.25% for Sample 2.     

Characteristics of hydrostatic bearing/seal parts for water hydraulic pumps and motors. Part 1: Experiment and theory

In this paper, the load-carrying capacity, power losses and stiffness of disk-type hydrostatic thrust bearings including the case of eccentric loading are discussed theoretically. The numerical analysis method is established based on a two-dimensional elastohydrostatic problem with an elastic deformation model, which is extended to adapt it for a non-axisymmetric load acting on the thrust bearing. The bearing is made of a combination of stainless steel/stainless steel and stainless steel/plastics. For the elastic materials, the maximum stiffness derived from, i.e., minimum film thickness is, larger than that of the rigid material in the range of a large ratio of pocket pressure and a hydrostatic balance ratio of over unity, which is defined as the ratio of the load to the maximum hydrostatic load-carrying capacity. The maximum load-carrying capacity and minimum power loss can exist in the domain of the hydrostatic balance ratio over unity for the case of the bearing consisting of elastic/rigid materials, in comparison with that composed of the same rigid materials. For the case of water, the power loss due to leakage flow is slightly larger but that due to frictional torque is much smaller than that in the case of hydraulic oil. Then, the total power loss is much smaller than that of hydraulic oil.     

RADIOACTIVE OR NATURAL TRACER。TECHNIQUES FOR LEAK DETERMINING OF DAM ABUTMENT

Infiltration and localization of preferential infiltration zones at the dam abutment are measured using radioactive tracer tests of flow in boreholes,meanwhile interconnection between boreholes and the energing water points is analysed.The theory and practice of radioactive tracer synthetic detective method are described to give methods and calculation formulae used under the condition of stable flow in single well to measure permeability coefficient and hydrostatic heads.Major single hole techniques including measurement for seepage line,velocity,rate of seepage flow and relationship of recharge of groundwater in aquifers are introduced briefly.The possibilities offered by natureal tracers are analysed,uincluding electric-conduct,pH-value and temperature of water as well as stable isotopes(D,^18O) and tritium.Furthermore,the sensibilities of this theory and methods were confirmed by detecting seepage flow field of Xinanjiang Dam.     

Deformation transition of intact coal induced by gas injection

Gas migration in coal bed is a multiple-physical process, of which not only includes gas desorption/diffusion through coal matrix and gas Darcy flow through the cleat system, but also results in deform...     

变粘度条件下静压支承滑靴副的理论研究

本文对变粘度条件下的静压支承滑靴副进行了一定的理论研究和分析，通过计算机仿真，得出了滑靴副泄漏流量和支承反力不仅与中心油室压力有关，而且还与流体的粘温系数、粘压系数、密度和比热容等有关的结论，为高速高压轴向柱塞泵的设计提供了一定的理论依据。     

雷达天线座静压轴承的可视化设计

本文通过对雷达天线座液体静压轴承的受力分析与结构设计，利用可视化编程工具Visual Basic6.0编制了一套快捷，实用的垫式静压轴承及节流器的设计软件，应用表明，该软件有助于提高设计效率和质量。     

Design and construction of a multi-sensor position monitoring system applied to key components of synchrotron sources

Abstracts High-accuracy position monitoring of key components is required for modern synchrotron sources, such as free-electron lasers and diffraction-limited storage rings. Although various position monitoring sensors have been adopted to monitor the displacement of key compo-nents in each direction in real time, these monitoring sys-tems are usually based on their own coordinate system. Data from such systems are meaningful when evaluating and examining the data from each positioning monitoring system in a unified coordinate system. This paper presents the design and construction of a multi-sensor position monitoring system (MPMS). A hydrostatic levelling sys-tem, a wire position sensor (WPS) and a tiltmeter are fixed to a stainless steel plate that has been calibrated by a coordinate-measurement machine. Several plates form the MPMS. The system must compensate for the sag of the stretched wires so that the WPSs create a straight line. The method of the coordinate transformation from the sensor coordinate system to the MPMS coordinate system was thoroughly studied. An experimental MPMS that includes five plates was setup in a 20-m tunnel, and a validation study to verify fully the feasibility of the MPMS was performed.     

Compression Stability of Reversed Austenite in 9Ni Steel

The effect of compressive stress on the stability of reversed austenite in 9Ni steel was investigated by uniaxial and hydrostatic compression.It was found that the uniaxial compressive pressure promoted the γ→α transformation,while the hydrostatic pressure suppressed the γ→α transformation.The pressure dependent transformation behavior can be explained according to thermodynamic analysis.     

Development of a novel point absorber in heave for wave energy conversion

This paper presents an advanced design methodology for electric power generation from the vast ocean wave energy. A novel single-buoy heaving device called wave energy converter (WEC) based on hydrostatic transmission (HST), or can be shortened as HSTWEC, is proposed to convert mechanical energy generated by ocean waves into electric energy. Modeling and simulations with both regular and irregular waves were then carried out to investigate working performances of the designed HSTWEC. The results showed that more than 78% of wave energy can be absorbed. In addition, an adaptive controller was designed to improve the performance of the suggested device. Effectiveness of the overall HSTWEC control system was finally proved by simulations.     

Application of the pressure grouting in the hydraulic tunnels

Present paper presents the application of pressure grouting in hydraulic tunnels subjected to high internal pressure of water. Structural analysis of the pressure grouting used for pre-stressing of concrete lining is shown along with the methods used to control the pressure grouting effects. The paper also presents a new experimental method for measuring the loss of water along the complete tunnel under operating conditions and a mathematical model for the evaluation of tunnel impermeability and functionality. All presented test methods have been developed and all measurements were performed by the “Jaroslav Cerni” Institute for Development of Water Resources in Belgrade (Serbia). These methods are presented on the example of a hydraulic tunnel of the “Bajina Basta” pumped storage plant in Serbia, during the stages of its construction and operation.