Rheological Force Research Articles

Petrophysical Properties of Tight Marl Reservoir and Its Influence on Fluid Percolation Capacity

Tight marl reservoir has always been a essential place for oil and gas storage in geophysical exploration. The oil under the Marl reservoir is a essential oil and gas storage resource in geophysical research, which accounts for more than half of all oil and gas resources. The marl reservoir has the characteristics of strong heterogeneity, complex lithology, and complex reservoir system, because most of them are buried deep underground, the research risk and cost are very high. In the past decade, most of the low-speed oil and gas resources developed in oil and gas fields have been exhausted, so the marl area has become an important distribution area of oil and gas research. This paper mainly studies the petrophysical properties of tight marl oil and gas reservoir and its influence on fluid percolation capacity. Through studying the characteristics of marl, it has the petrophysical properties of oil and gas reservoirs, pre-stack seismic inversion of shale oil and gas reservoirs, further exploration of natural resources, and its use to better benefit mankind. In this paper, the core sample basic parameter measurement, stress model, rock rheological force, petrophysical application method and related experiments are used to study the petrophysical properties of tight marl oil and gas reservoir and its influence on fluid percolation capacity, which is of great significance to the long-term stability of high arch dam, And the utilization and production of natural resources are of great practical engineering significance and social significance. The results show that the rock content varies about 5% in different rock physical properties, which shows different fluid percolation capacity. In the analysis of marl oil and gas reservoirs, it has important theoretical significance and engineering value to analyze the rheological effect of seepage field and stress field of dam bedrock under long-term load.

Induction of inverted morphology in brain organoids by vertical-mixing bioreactors

Organoid technology provides an opportunity to generate brain-like structures by recapitulating developmental steps in the manner of self-organization. Here we examined the vertical-mixing effect on brain organoid structures using bioreactors and established inverted brain organoids. The organoids generated by vertical mixing showed neurons that migrated from the outer periphery to the inner core of organoids, in contrast to orbital mixing. Computational analysis of flow dynamics clarified that, by comparison with orbital mixing, vertical mixing maintained the high turbulent energy around organoids, and continuously kept inter-organoid distances by dispersing and adding uniform rheological force on organoids. To uncover the mechanisms of the inverted structure, we investigated the direction of primary cilia, a cellular mechanosensor. Primary cilia of neural progenitors by vertical mixing were aligned in a multidirectional manner, and those by orbital mixing in a bidirectional manner. Single-cell RNA sequencing revealed that neurons of inverted brain organoids presented a GABAergic character of the ventral forebrain. These results suggest that controlling fluid dynamics by biomechanical engineering can direct stem cell differentiation of brain organoids, and that inverted brain organoids will be applicable for studying human brain development and disorders in the future.

Analyzing the influence of the disk motion on longitudinal oscillations of a beam with rheological properties

The paper gives the analysis of the influence of longitudinal oscillations of a beam, which is caused by a circular hard disk motion along the beam, on the mode of disk motion. The problem of rolling the disk on the plane in its various formulations has been investigated by different researchers as well as by the authors of this paper. The paper considers two variants of properties of the beam material: an elastic beam and a viscoelastic beam, which fits the Kelvin rheological model and has relaxation and creep properties. When solving the problem, the Fourier method is used as a method of separation of variables. When examining the beam, and assuming it as hereditary deformable, a rheological force of the reaction is introduced, this depends on both on longitudinal strains and on the rate of these strains The result is presented as functions of time which are adaptable for numerical integration. It is shown that oscillations of a rheological beam are produced by a moving disk and can be considered as self-oscillations.

Analysis motion of borehole-expander - device for densifying subsurface walls of boreholes

The paper introduces an algorithm for analyzing the following solids of rotation and their motion: a bearing roller and a borehole-expander - a device for densifying subsurface walls of boreholes. These devices are moving in the environment with rheological properties typical for the Kelvin model, with nonholonomic constraints that impose restrictions on the velocity of the disk points. The research presents both mathematical models of the standard viscoelastic hereditary-deformed cylinder and a weakly singular model proposed by A.R. Rzhanitsin, representing a nonautonomous system of differential equations in the form of Routh. The fact that this system is nonautonomous complicates its sustainability analysis. The presentation of a rheological force in a differential form does not lead to a system of equations in the form of Chaplygin. The solution was found by numerical integration. The solution is multivariant as one initial value of generalized coordinates and generalized accelerations corresponds to a series of initial generalized speeds. It is shown that the disk is not able to fall in the course of motion because its point of contact being in a radial vibration is still within the tension region of the cylinder wall.

Non-bacterial thrombotic endocarditis in the right atrium caused by pectus excavatum.

BackgroundNon-bacterial thrombotic endocarditis (NBTE) is an uncommon pathological situation, which involves the presence of bland, fibrin-platelet thrombi. It usually occurs at the endocardium of cardiac valves, in association with endothelial injury and a hypercoagulative state. However, NBTE on the endocardium at the right atrial free wall in a patient without any apparent hypercoagulative background is rarely reported.Case presentationA girl aged 4 years with severe pectus excavatum was referred to our hospital for treatment of a recurrent right atrial tumor. The tumor was removed concomitant with pectus excavatum repair. The tumor was revealed as recurrent thrombus. Pathological findings showed that NBTE caused by an operative scar on the endocardium of the right atrium and sustained rheological stress in the right atrium due to compression from pectus excavatum lead to recurrent thrombus formation. Three years after the discontinuation of anticoagulation therapy, no sign of thrombus formation was found.ConclusionsTo our knowledge, this is the first report of NBTE related to an interaction between sustained rheological stress from cardiac compression and endocardial injury. In such patients, we recommend concomitant chest wall repair when the operative scar is present at the site of the rheological force.

Finite Element Modeling and Physical Property Estimation of Rheological Food Objects

<p>The purpose of this study is to accurately simulate the rheological behaviors of food objects undergoing a loading-unloading operation using finite element (FE) model. Due to the presence of residual deformation, it is difficult to model rheological behaviors. Especially, it is hard to accurately reproduce both rheological force and residual deformation simultaneously. In this study, objects made of food materials were tested. Force and deformation measurements were recorded for parameter estimation. Constitutive models were investigated for describing rheological behaviors. A parallel five-element model including two dual-moduli viscous elements was proposed to accurately predict both rheological force and residual deformation simultaneously. 2D/3D FE model was formulated for simulating rheological behaviors. To estimate the parameters, an effective four-step method was established based on nonlinear optimization which aimed at minimizing the differences of forces and deformation between simulation and experiments. The proposed FE model and parameter estimation method were validated in both 2D and 3D cases and good agreements were achieved in both rheological forces and deformation between numerically simulated and experimentally measured data.</p>

Rheological and Morphological Properties of Phosphorus-Containing Polysulfones

Polysulfones with bulky phosphorus pendant groups, obtained by chemical modification of the chloromethylated polysulfones were subjected to rheological, surface tension and atomic force microscopy investigations, to establish the processing/morphology/property relationships of these polymers. The effects of the substitution degrees, of the bulky phosphorus pendant groups bound in different positions, and also of intermolecular and intramolecular interactions, influenced the rheological results. High hydrophobicity, low work of water adhesion and low adhesion to interface, would be advantageous for some applications. Atomic force microscopy showed that increasing of the bulky phosphorus pendant groups influences the pores characteristics and roughness, confirming the poor adhesion.

Modeling and estimation of rheological properties of food products for manufacturing simulations

The rheological properties of food products related to their engineering and manufacturing were modeled and estimated. A 2D/3D dynamic FE model for the simulation of uniform objects was formulated based on a five-element physical model and was further extended to deal with nonuniform layered objects. Three kinds of food materials (Japanese sweets) were tested to assess their deformation and force behaviors. An approach based on inverse FE optimization was then proposed to estimate the rheological properties of these objects. Two different sets of rheological parameters were estimated for describing the deformation and force respectively. The estimated parameters were then employed to simulate three-layered food products (consisting of two different materials) in two kinds of compressive operations. The validation results showed that the FE model and property-estimation method accurately reproduced both rheological force and deformation. The FE model can be used to predict the rheological behaviors of food products during their manufacture.

Dry Spinning of Polymer Fibers in Ternary Systems

Abstract In this work, predictions based on the 2D dry spinning model developed in Part I of this work [2] along with a die swell subroutine supplied by an industrial company, are used to compare with fiber concentration and elongation to break data from an industrial spinline. Die swell ratio predictions agree well with measured values and solidification along the spinline is shown to be due to homogeneous glass transition in the absence of phase separation. Concentration profiles along the spinline are well fit by the model using previously determined prefactors for the diffusion coefficients. A good correlation of elongation at break data is found to occur with a characteristic variable σGTP, the ratio of the rheological force of the viscoelastic Giesekus contribution to the total rheological force (Giesekus + viscous) at the glass transition point. Moreover, the regression obtained from this fit can be further used to make predictions for elongation at break under different operating conditions. Finally, the effects of spinning conditions and model parameters on fiber mechanical properties were investigated.

DESCRIPTIVE ANALYSIS OF CARAMEL TEXTURE1

ABSTRACTOral sensory evaluation of caramel texture was conducted using six texture terms and results were compared to instrumental testing of texture. Trained panelists (n = 11) evaluated 6 caramel formulations by descriptive analysis. Mean texture values indicated that a slight increase in sweetened condensed skim milk and vegetable fat content (1% w/w at a 2:1 ratio) significantly decreased stickiness (P≤ 0.05). Decreasing corn syrup dextrose equivalent (DE) decreased stickiness and increased hardness (P≤ 0.05). Pearson correlation coefficients revealed that stickiness to teeth while chewing, toothpacking, and tooth adhesiveness were highly correlated with one another (P≤ 0.05). Sensory hardness, cohesiveness, and number of chews were correlated with the rheological properties of storage modulus and viscosity, while stickiness was correlated with probe tack force (P≤ 0.05). Such correlations show that fundamental rheological and tack force measurements can be used to help determine molecular mechanisms for sensory texture and stickiness.

Self-assembly of submicron particles between electrodes

A method for the fabrication of opal films between parallel transparent electrodes is described. Monodispersed particles are assembled by taking advantage of the rheological force induced by the evaporation of a solvent in a thin capillary cell. Three-dimensional opal films with controllable thickness could be fabricated, in which a regular hexagonal arrangement of particles parallel to the substrates over a large area was observed. Such a sandwich-like photonic device may find applications in fabricating electrically tunable photonic crystals.

Kinetics of thermal softening of potato tissue heated by different methods

The kinetics of thermal softening of potato tissue heated by steaming, steaming+hot air and microwave exposure were evaluated using the rheological properties from four objective methods as firmness indicators. In the three heat treatments, the rate of thermal softening of tissue could be described by two simultaneous first-order kinetic mechanisms. Shear rheological properties were best for studying softening of the tissue with these methods on the basis of chemical kinetic theory. A comparison of kinetic parameters showed that steaming produced a greater degree of softening than the other two heating methods used. The firmness ratios for shear force showed that approximately 16% of the firmness of fresh potato is retained after steaming treatments as compared to 46% and 36%, respectively, for steaming+hot air and microwave. The loss of moisture of samples accounted for the increase in the firmness ratios, especially in steaming+hot air treatments, resulting in a potato with greater firmness but with a texture unacceptable to the consumer. Tension rheological properties and relaxed force detected the loss of moisture to a more significant degree and could therefore be considered very suitable for studying thermal treatments that involve the drying of tissues. With these heating methods, gelatinization contributes less than cell wall structure to potato tissue softening as determined either by kinetic parameters or by microscopic observations.

Rheological behavior of aromatic polyamide gel fibres in amide-salt systems

For a given polymer-solvent-precipitator system, specific features in the deformational behavior of the gel related both to sharp changes in the quality of the precipitator with a fixed composition and to the components of the spinning medium are observed during precipitation. For certain ratios of solvent (DMAA) and precipitator (water) in the precipitating system, sharp changes are observed in the deformational behavior of the gel fibre, which is confirmed by the uneven changes in the maximum possible spinneret drawing and rheological force (tension in take-up on a disk). These concentration ranges of DMAA (40, 45–55, 55–60, and 60–65% DMAA) are also characteristic of a sharp change in the precipitating power of the coagulation medium, determined with the precipitation number.

Role and Initiation Mechanism of the Interaction of Glycoprotein Ib With Surface-Immobilized von Willebrand Factor in a Solid-Phase Platelet Cohesion Process

To know the role and initiation mechanism of the interaction of glycoprotein (GP) Ib with surface-immobilized von Willebrand factor (vWF), we examined the effect of shear stress levels on platelet binding to vWF-coated plates using a cone-and-plate type viscometer capable of loading various levels of shear stress. The extent of platelet binding to immobilized vWF reached a plateau at the shortest period tested (20 seconds) under high shear stress (90 dyne/cm2), whereas 9 to 12 minutes was necessary for saturable platelet binding under static conditions. This shear effect, which was found to be dependent on the vWF-GP Ib interaction, was observed even under the lowest shear stress (1.5 dyne/cm2) examined. In contrast with the high shear effect previously reported to initiate the interaction of GP Ib with soluble vWF, these results indicate that relatively low levels of shear stress can promote the interaction of GP Ib with surface-immobilized vWF. This effect of shear stress was observed regardless of the manner in which vWF was immobilized, suggesting that immobilization itself and not, as previously hypothesized, a conformational change in vWF induced by direct adsorption to the surface is responsible for the enhanced GPIb binding. Thus, the present findings suggest that the vWF-GP Ib interaction contributes optimally to rapid platelet cohesion on a thrombogenic surface when vWF is in a static state and when platelets are moved by an appropriate rheological force such as low shear stress.

Growth of a dent on an isothermal fluid filament in uniaxial extension a spinnability model in Lagrangian coordinate

Growth of an arbitrarily shaped dent made on a filament of power law and Maxwell type fluids being uniaxially extended was analysed in the Lagrangian coordinate assuming inertia, surface tension, gravity and air drag forces to be negligible in comparison to the rheological force.