Studies on the flow and distribution of leukocytes in mesentery microcirculation of rats

AIM To study the effect of leukocyteendothelium interaction (LEI) on the flow anddistribution of leukocytes in microcirculationunder physiological condition.METHODS A microcirculation image multipleparameter computer analysis system (MIMPCAS)was used to study the flow and distribution ofleukocytes in mesentery microcirculation of ratsIn vivo.RESULTS The difference of visible leukocyteflux (VLF) was as high as 131 times in thearterioles and venules with similar diameter andblood velocity. The visible leukocytes rolledalong the blood vessel wall as a" jerky"movement. The frequency distribution of thevisible leukocyte velocity (VLV) showed a "twopeak" Curve. The low peak value was at 10 pm/ s-- 15 pm/ s while the high peak fell between25 pm/ s-- 30 pm/ s. With the increase of diameterof venules, VLF increased while the VLVremained at the same level. With the increase ofRBC velocity, VLV trends to elevate and VLF tofal I down.CONCLUSION The results herein might providea basic theory for the study on the mechanism ofLEI under physiological condition and novelmethods for the prevention and treatment of highLEI in many pathological

Numerical study on three-dimensional flow field of continuously rotating detonation in a toroidal chamber

Gaseous detonation propagating in a toroidal chamber was numerically studied for hydrogen/oxygen/nitrogen mixtures. The numerical method used is based on the three-dimensional Euler equations with detailed finiterate chemistry. The results show that the calculated streak picture is in qualitative agreement with the picture recorded by a high speed streak camera from published literature. The three-dimensional flow field induced by a continuously rotating detonation was visualized and distinctive features of the rotating detonations were clearly depicted. Owing to the unconfined character of detonation wavelet, a deficit of detonation parameters was observed. Due to the effects of wall geometries, the strength of the outside detonation front is stronger than that of the inside portion. The detonation thus propagates with a constant circular velocity. Numerical simulation also shows three-dimensional rotating detonation structures, which display specific feature of the detonation- shock combined wave. Discrete burning gas pockets are formed due to instability of the discontinuity. It is believed that the present study could give an insight into the interest- ing properties of the continuously rotating detonation, and is thus beneficial to the design of continuous detonation propulsion systems.

Modeling study on the flow patterns of gas–liquid flow for fast decarburization during the RH process

A water model and a high-speed video camera were utilized in the 300-t RH equipment to study the effect of steel flow patterns in a vacuum chamber on fast decarburization and a superior flow-pattern map was obtained during the practical RH process. There are three flow patterns with different bubbling characteristics and steel surface states in the vacuum chamber： boiling pattern（BP）, transition pattern（TP）, and wave pattern（WP）. The effect of the liquid-steel level and the residence time of the steel in the chamber on flow patterns and decarburization reaction were investigated, respectively. The liquid-steel level significantly affected the flow-pattern transition from BP to WP, and the residence time and reaction area were crucial to evaluate the whole decarburization process rather than the circulation flow rate and mixing time. A superior flow-pattern map during the practical RH process showed that the steel flow pattern changed from BP to TP quickly, and then remained as TP until the end of decarburization.

AN APPLICATION OF TOPOLOGICAL ANALYSIS TO STUDYING THE THREE-DIMENSIONAL FLOW IN CASCADES;PART I—TOPOLOGICAL RULES FOR SKIN-FRICTION LINES AND SECTION STREAMLINES

Based on the working of Lighthill and Hunt et al., in the present paper the author has established the topological rules adapting to analysing the skin-friction lines and the section streamlines in cascades. These rules are (1) for a rotor cascade without shroud band, the total number of nodal points equals that the saddle points on the skin-friction line vector fields in eachpitch range; (2) for an annular or straight cascade with no-clearances at blade ends, the total number of saddle points is two more than that of nodal points on the skin-friction line fields in a pitch; (3) the total number of saddles in the secondary flow fields on cross-sections in cascade is one less than that of nodes; (4) in the section streamline vector fields on a meridian surface penetrating a flow passage, and on leading and trailing edge sections, the total number of nodes is equal to that of saddles; (5) on the streamline vector fields of a blade-to-blade surface, the total number of nodes is one less than that of saddles.

CLINICAL OBSERVATION ABOUT THE EFFECT OF BLOOD-LETTING OF JING-POINTS ON CEREBRAL BLOOD FLOW IN STROKE PATIENTS AT THE EARLY STAGE AND EXPERIMENTAL STUDY ON ITS MECHANISMS IN THE RABBIT

In this paper, the authors sum their research results about the effect of blood-letting of Jing (Well)-point on cerebral blood flow both in stroke patients and in experimental cerebral ischemia, cerebral hematoma and hypertension rabbits. In 30 cases of stroke (cerebral hemorrhage and cerebral infarction) patients, blood flow state of the anterior cerebral artery (ACA), middle cerebral artery (MCA) and the posterior cerebral artery (PCA), and the blood flow velocity of the bilateral vertebral artery (VA) and the basil artery (BA) are determined before and after pricking blood of the Twelve Jing-points. In experimental cerebral ischemia (by occlusion of the common carotid artery) rabbits, cerebral hematoma model rabbits and intravenous injection of noradrenaline induced hypertension rabbits, rheoencephalogram (REC) is detected before and after blood letting of the twelve "Jing"-points. In these 30 stroke patients, ultrasound Doppler examination’s results show that in 22 cases (73.33%) whose blood flow velocity decreases, after blood-letting of the 12 Jing-points, it increases significantly (P<0.01); in the rest 8 cases ( 26.67%) whose blood flow velocity speeds up, after treatment, it decreases evidently (P<0.01), showing a good dual-directional regulative effect of blood-letting therapy. In experimental cerebral ischemia rabbits, cerebral hematoma rabbits and hypertension rabbits whose REG lowers in the amplitude apparently (P<0.01), after blood letting stimulation of the 12 Jing-points, it increases at different degrees. Three patterns of stimulation as blood letting stimulation, pain stimulation and Jing-point stimulation, also the 3 factors of blood-letting therapy, may contribute to their effect on improvement of the cerebral blood flow. Somatic afferent nerve, sympathetic nerve of the vascular wall, central cholinergic nerve (M receptors) and adrenergic nerve (α receptors) participate in the effect of blood letting on cerebral blood flow.

A STUDY ON YIELD AND FLOW OF ORTHOTROPIC MATERIALS

On the assumption that the yield criterion of orthotropic materials is isomorphic with Huber-Mises criterion of isotropic materials, we put forward a dimensionless stress yield criterion, and obtained the associated plastic flow law. Using experimental stress-strain curves in various simple stress states, generalized effective stress-strain formulae may be derived correspondingly in various forms.

Simulation and Calibration of Hydro-Debris 2D Model （HD2DM） to Predict the Particle Segregation Processes in Debris Flow

The principal aim of a vertical two-dimensional numerical model development is for estimating the particle tracing and mechanism of 10 mm and 2.5 mm debris. The particle tracing movement can be visually analyzed by using a high speed video camera （HSVC）. A numerical model was developed using the Marker and Cell Method, which involves a Subgrid-Scale （SGS） model and the Particle Source in Cell （PSI-Cell） Method. The transportation processes of debris and air bubble were simulated in lagrangian form by introducing air bubbles and debris markers. Air bubble movement characteristics were simulated by this numerical model. Bigger particles flow at the upper part, while smaller particles attach near to the bottom. This phenomenon is similar to what we observed in the experimental studies. As a conclusion, the calibration processes for velocity was successful. The value of virtual mass （CM） was found to be one of the most important criteria that should be considered in the calibration process, as this parameter dominates fundamental characteristics of sediment particle movement in the lagrangian numerical scheme. The best fitted CM in this study was 0.35. The mean average velocity value ranging from 1.2% to 22.61% is obtained from the velocity results of numerical studies compared to the experimental studies.

NUMERICAL INVESTIGATION OF THREE-DIMENSIONAL VISCOUS INCOMPRESSIBLE FLOWS IN DIVERGENT CURVED CHANNELS AND TURBULENT MODEL STUDY

In order to make the numerical calculation of viscous flows more convenient for the flows in channel with complicated profile governing equations expressed in the arbitrary curvilinear coordinates were derived by means of Favre density-weighted averaged method, and a turbulent model with effect of curvature modification was also derived. The numerical calculation of laminar and turbulent flown in divergent curved channels was carried out by means of parabolizeil computation method. The calculating results were used to analyze and investigate the aerodynamic performance of talor cascades in compressors preliminarily.

Studies on flow injection analysis of platinum metals——I. Flow injection catalytic determination of ruthenium by phthalin-hydrogen peroxide reaction

A new method has been developed for the determination of trace ruthenium by flow in- jection analysis. The proposed method is rapid, simple and sensitive. The method has a limit of detection for ruthenium of 0.020 μg/mL and permits 70 determinations per hour. The method has been applied to determine ruthenium in refined ore with satisfactory result.

AN EXPERIMENTAL STUDY ON THE FLOW FIELDS OF THE WEST LAKE BY ELECTRO-HYDRODYNAMIC ANALOGUE METHOD

Electro hydrodynamic analogue (EHA) method is applied to study the flow fields in the West Lake. It gives out a satisfactory result on water velocities and discharges of the bridge openings.

A numerical study of sound field radiated by the flow around a circular cylinder

The Von-Karman vortex street flow behind a circular cylinder is successfully solved at Re= 100 for incompressible N- S equations in the form of stream function and vorticity. The method adopted here involves ADI - BGE schemes, a recent treatment of body boundary conditions and a new acceptable perturbation model. The solutions of the flow field obtained here are better than previous numerical ones and agree with the experimental data closer. Therefore, it can be used to study sound field numerically. The Curie equation is directly and numerically solved to analyze the distribution of sound sources and the characteristics of their radiated sound field at Re= 100 and to compare with the solution from the theory of vortex sound. It is shown that this method is successful.