波流作用下太湖水体悬浮物输运实验及模拟

利用室内外实验和数学模型对波浪和湖流共同作用下太湖水体悬浮物输运过程进行了研究。结果表明：当太湖日平均风速在2—8m／s时，水体悬浮物再悬浮通量与平均风速符合正相关关系；太湖悬浮物沉降属于絮凝沉降。悬浮物浓度较低时，其沉降速率与浓度无明显的相关关系；而浓度较高时，沉降速率随浓度升高而增大。悬浮物浓度和沉降速率符合logistic函数；将太湖湖流模型和波浪模型耦合，有效地反映了太湖的水动力过程；在太湖悬浮物模型中，引入底泥起悬条件，将底泥的起悬量与沉降量分开处理，有效地模拟了太湖悬浮物的输运过程。模拟结果表明太湖悬浮物沿岸区域受湖流的影响较大，湖心区域受波浪影响较大。

X射线辐射输运分解实验研究

在“星光Ⅱ”激光装置上进行了X射线辐射输运分解实验研究.实验中利用高时空分辨的MCP选通X射线皮秒分幅相机和软X射线条纹相机从缝口观测腔内壁X射线辐射时空分布,得到X射线在腔中的输运速率、X射线持续发射时间和轴向强度衰减量;利用X射线CCD针孔透射光栅谱仪观测到腔内X射线辐射光谱随空间位置的变化,得到X射线在输运过程中被多次吸收和发射后谱的变化特征;用X射线二极管和亚千X射线能谱仪分别得到源和输运末端X射线辐射总量和辐射温度.介绍了实验中采用的诊断技术和实验方法,并给出了获得的典型结果.

Digital core approach to the effects of clay on the electrical properties of saturated rocks using lattice gas automation

Clay has a significant influence on the relationship between resistivity index I and water saturation Sw （i.e, I-Sw relationship） of reservoir rocks because it complicates the current paths of these rocks. It is difficult to reveal the physical mechanisms of these clay effects on the conductivities of various rocks by physical laboratory measurements because the pore structure, micro distribution and content of clay inside a rock can not be observed and controlled during the experiments. We present a digital rock approach to study these clay effects on the electrical transport properties of reservoir rocks at pore scale using lattice gas automation （LGA） method. The digital rock samples are constructed with the information of grain size distribution from SEM images of reservoir rocks. The LGA is then applied on these digital rocks fully saturated with fluids to simulate the electrical transport properties for revealing the effects of volume and distribution patterns of clay on the non-Archie behaviors of the I-Sw relationship. The very good agreement between the simulated results and the laboratory measurements clearly demonstrates the validity of the LGA in numerical research of rock physics. Based on these studies, a new model has been developed for quantitatively describing the relationship between the saturation exponent and the volume of clay （Vsh）. This development may improve the evaluation for the fluid saturations in reservoir rocks.

Experimental Study on the Resistance of a Transport Ship Navigating in Level Ice

This study investigates the resistance of a transport ship navigating in level ice by conducting a series of model tests in an ice tank at Tianjin University. The laboratory-scale model ship was mounted on a rigid carriage using a one-directional load cell and then towed through an ice sheet at different speeds. We observed the ice-breaking process at different parts of the ship and motion of the ice floes and measured the resistances under different speeds to determine the relationship between the ice-breaking process and ice resistance. The bending failure at the shoulder area was found to cause maximum resistance. Furthermore, we introduced the analytical method of Lindqvist （1989） for estimating ice resistance and then compared these calculated results with those from our model tests. The results indicate that the calculated total resistances are higher than those we determined in the model tests.

Computer simulation of flow and mixing at the duodenal stump after gastric resection

AIM： To investigate the flow and mixing at the duodenal stump after gastric resection, a computer simulation was implemented. METHODS： Using the finite element method, two different Billroth fl procedure cases （A and B） were modeled. Case A was defined with a shorter and almost straight duodenal section, while case B has a much longer and curved duodenal section. Velocity, pressure and food concentration distribution were determined and the numerical results were compared with experimental observations. RESULTS： The pressure distribution obtained by numerical simulation was in the range of the recorded experimental results. Case A had a more favorable pressure distribution in comparison with case B. However, case B had better performance in terms of food transport because of more continual food distribution, as well as better emptying of the duodena section. CONCLUSION： This study offers insight into the transport process within the duodenal stump section after surgical intervention, which can be useful for future patient-specific predictions of a surgical outcome.

Experimental Investigation and Numerical Simulation for Bacteria Transport in Soil

A thorough understanding of bacteria transport in soil and groundwater is vital to the successful practice of environmental bioremediation.In this work,a dual-process adsorption with growth and decay model of bacterial transport was proposed.The onsite soil and the high efficiency methyl tertbutyl ether （MTBE） degrading bacterium Chryseobacterium sp.A-3,was used in the experiments.The model was validated using one-dimensional soil column experiments.The results show that the dual-process adsorption with growth and decay model proposed well describes the migration mechanism of microorganisms in soil and groundwater environment.According to the model analysis and simulation,the bacterial transport is enhanced as flow velocity and inlet cell concentration increase.Compared with the contaminant MTBE,the bacteria show stronger transport capacity but the irreversible straining in soil prevents the bacteria from transporting longer than MTBE.The results have certain instructive significance to the insitu contamination remediation operation.

Philosophy of Science and Post-theoretical Life-World

Philosophy of science has arisen as alternative to epistemology, because scientific development wanted another kind of explanation than traditional epistemological one. The latter kind of explanation is theoretically loaded and based on latent ontological assumptions. Epistemology offers science a ＂road map＂ for researcher＇s thinking. Thus epistemology knows what science should be, and philosophy of science take science for granted--existing as an empirical fact. Philosophy of science had always been a reflective and critical discipline that didn＇t want any a-priory knowledge. The main distinction between these fields of knowledge is as follows： epistemology is theoretical and projective kind of knowledge whereas philosophy of science is a non-theoretical, or better, a ＂post-theoretical＂ discipline. All facts and statements arising from philosophy of science lie within the heterogeneous space, where there is continuous transit of pre-theoretical, theoretical and post-theoretical versions of knowledge. The inevitability of conservation and utilization of human thought products is recognized, which is supplemented by the need to study the impact of theoretical thinking upon social practices.

Concentration of Vinasse Using Membrane Filtration Processes

The application of single nanofiltration （NF） and sequential filtration of microfiltration （MF） and NF for the concentration of vinasse were studied. Filtration experiments were performed at 60 ℃, 500 rpm and different transmembrane pressures using four commercial membranes： MF, PVDF 0.2 μm; NF, PES 300, 500 and 1000 Da. The process effectiveness was evaluated through the permeate flux and the total solids （TS） concentration in the retentate. Because the retention of TS and permeate fluxes were very similar for MF, PVDF-0.2 membrane at 0.10 MPa was selected because of its lower power consumption. The best conditions tested for NF were the following： PES-1000 at 3.50 MPa with a flux of 183.2 kg/m^2 h at a volume reduction factor （VRF） of 2, under which 68% of solids were retained. For the MF ＋ NF, a PES-1000 at 3.50 MPa was selected because a higher permeate flux was achieved at a VRF of 4, and PES-500 at 3.50 MPa because a higher retention of TS was achieved compared to the other experiments. A single NF resulted in a retentate concentration that was almost twice as high as the hybrid MF and NF process, allowing reduced costs in its transportation from distilleries to distant areas.

Chloride ion transport performance in slag mortar under fatigue loading

The transport performance of chloride ion in slag cement mortar was investigated experimentally. In the self-designed experiment, fatigue loading was coupled simultaneously with ion transportation process, the diffusion law of chloride ion was obtained by titration and the AE (acoustic emission) technique was employed to detect the real-time damage distribution in the mortar specimen. The results for fatigue stress levels of 0.3, 0.4 and 0.5 and slag contents of 0, 10%, 30% and 50% showed that fatigue loading accelerated the diffusion of chloride ion in mortar and the acceleration effect increased with the increase in stress levels. Slag addition was found to improve anti-chloride ion erosion performance effectively with the best substitution level at 30%, because the inhibition effect of slag on chloride ion diffusion diminished when the slag content exceeded 30%. The comparative experiments indicated that dynamic load has a significant effect on the transport performance of chloride ion in slag cement mortar.

Experimental study of viscosity characteristics of hightemperature heat transfer molten salts

In this paper several kinds of high temperature molten salts were investigated experimentally on viscosity-temperature characteristics with high-temperature viscometer.The viscosities of the molten salts were measured and compared with those from references to verify the reliability of the viscometer and measuring methods,and a good agreement was observed from the comparisons.Then,two new high-temperature molten salts were made from the HITEC salt by some additives and the viscosity-temperature profiles of them were obtained by experiments.The results show that the new molten salts have much lower viscosities,thus suitable for reducing the flow resistance in transportation system of high-temperature solar thermal power generation.