Sample records for capillary permeability

  1. Capillary permeability in adipose tissue

    Paaske, W P; Nielsen, S L


    A method for measurement of capillary permeability using external registration of gamma emitting isotopes after close arterial bolus injection was applied to the isolated inguinal fat pad in slightly fasting rabbits. An average extraction of 26 per cent for 51Cr-EDTA was found at a plasma flow of...... about 7 ml/100 g-min. This corresponds to a capillary diffusion capacity of 2.0 ml/100 g-min which is half the value reported for vasodilated skeletal muscle having approximately twice as great capillary surface area. Thus, adipose tissue has about the same capillary permeability during slight metabolic...

  2. Method to calculate reservoir permeability using nuclear magnetic resonance logging and capillary pressure data

    In view of the problems of SDR and Tim-Coates models in calculating permeability using nuclear magnetic resonance logging data, based on the fact that nuclear magnetic resonance T2 distribution and capillary pressure curves reflect the reservoir pore structure, a method was presented to calculate reservoir permeability using nuclear magnetic resonance logging and capillary pressure data. The correlation between Swanson parameter and permeability was established by comparing 31 core samples which were measured by mercury penetration and nuclear magnetic resonance logging. Considering the problem that capillary pressure data are limited by their quantity, the good correlativity between T2 geometric mean value of lateral relaxation time of nuclear magnetic resonance and Swanson parameter can be used to determine the Swanson parameter and to calculate reservoir permeability consecutively. The processing of the data in well A yields a permeability closer to the result of core analysis, and this indicates the accuracy of the method. (authors)

  3. Tracer kinetic modelling in MRI: estimating perfusion and capillary permeability

    The tracer-kinetic models developed in the early 1990s for dynamic contrast-enhanced MRI (DCE-MRI) have since become a standard in numerous applications. At the same time, the development of MRI hardware has led to increases in image quality and temporal resolution that reveal the limitations of the early models. This in turn has stimulated an interest in the development and application of a second generation of modelling approaches. They are designed to overcome these limitations and produce additional and more accurate information on tissue status. In particular, models of the second generation enable separate estimates of perfusion and capillary permeability rather than a single parameter Ktrans that represents a combination of the two. A variety of such models has been proposed in the literature, and development in the field has been constrained by a lack of transparency regarding terminology, notations and physiological assumptions. In this review, we provide an overview of these models in a manner that is both physically intuitive and mathematically rigourous. All are derived from common first principles, using concepts and notations from general tracer-kinetic theory. Explicit links to their historical origins are included to allow for a transfer of experience obtained in other fields (PET, SPECT, CT). A classification is presented that reveals the links between all models, and with the models of the first generation. Detailed formulae for all solutions are provided to facilitate implementation. Our aim is to encourage the application of these tools to DCE-MRI by offering researchers a clearer understanding of their assumptions and requirements. (topical review)

  4. Determining CO2-brine relative permeability and capillary pressure simultaneously: an insight to capillary entrance and end effects

    Chen, X.; Kianinejad, A.; DiCarlo, D. A.


    CO2-brine relative permeability relations are important parameters in modeling scenarios such as CO2 sequestration in saline aquifers and CO2 enhanced recovery in oil reservoir. Many steady-state experimental studies on CO2-brine relative permeability showed that the CO2-brine relative permeability differs greatly from typical oil-brine relative permeability. Particularly, they reported a very small endpoint CO2 relative permeability of 0.1~0.2 at a relative high residual water saturation of 0.4~0.6. In this study, we hypothesize the measured low endpoint CO2 relative permeability in previous studies was an experimental artifact that is primary due to low CO2 viscosity. We conducted steady-state CO2 drainage experiments by co-injecting equlibrated CO2 and brine into a long (60.8 cm) and low permeability (116-mD) Berea sandstone core at 20 °C and 1500 psi. During every experiment, both the overall pressure drop across the core and the pressure drops of the five independent and continuous sections of the core were monitored. The in-situ saturation was measured with a medical X-ray Computed Tomography (CT) scanner. In the center three sections where saturation was uniform, we determined the relative permeability to both brine and CO2 phases. In the entrance and exit sections, both measured pressure gradients and saturation were non-uniform. To cope with this, we make several self-consistent assumptions that reveal the nature of capillary entrance and effect in steady-state two-phase core flooding experiments. Based on these assumptions we determined the relative permeability to CO2 and CO2-brine capillary pressure simultaneously using measured pressure drops. We found: (1) a much higher endpoint CO2 relative permeability of 0.58 at a water saturation of 48%, (2) the entrance region with non-uniform saturation expanded CO2 relative permeability data to much lower water saturation, (3) the determined CO2-brine capillary pressure curve is self-consistent and matches

  5. Decreased capillary permeability and capillary density in patients with systemic sclerosis using large-window sodium fluorescein videodensitometry of the ankle

    Hettema, M E; Zhang, D; Stienstra, Y; Oomen, P N H; Smit, Andries; Kallenberg, C G M; Bootsma, H


    OBJECTIVE: Local capillary permeability in patients with SSc has been reported increased when assessed by nail-fold capillaroscopy. We measured capillary permeability at a clinically less affected site by using large-window fluorescein videodensitometry of the ankle. We hypothesized that increased c

  6. Measurement of capillary permeability in canine heart determined by the tissue injection, residue detection method

    Svendsen, Jesper Hastrup; Paaske, W P; Haunsø, S; Sejrsen, P


    In previous studies the tissue injection, residue detection method failed to provide results of diffusional capillary permeability comparable to those of other methods. For this reason we reconsidered the kinetic theory and found that it is necessary to take into account the apparent (restricted......S-product similar to those obtained with a number of other methods based on indicator diffusion, so the tissue injection, residue detection method in its new kinetically correct formulation could prove useful in clinical studies of capillary permeability since it is applicable to determination of relative changes...

  7. PKQuest: capillary permeability limitation and plasma protein binding – application to human inulin, dicloxacillin and ceftriaxone pharmacokinetics

    Levitt, David G.


    Background It is generally assumed that the tissue exchange of antibiotics is flow limited (complete equilibration between the capillary and the tissue water). This assumption may not be valid if there is a large amount of plasma protein binding because the effective capillary permeability depends on the product of the intrinsic capillary permeability (PS) and the fraction of solute that is free in the blood (fwB). PKQuest, a new generic physiologically based pharmacokinetic software routine ...

  8. A capillary-based method determining the permeability of sand layer for geothermal applications

    Huajun Wang, Hongjie Zhao, Chengying Qi


    Full Text Available The hydraulic permeability is a major parameter for modelling the heat transfer of borehole heat exchangers (BHEs in an aquifer, where the groundwater advection has a significant impact on the thermal performance of BHEs. This paper presented a novel method determining the hydraulic permeability of sand layer using the theory of capillary rise (CR. In this method, based on the observation on the dynamic CR process, the equilibrium height together with the fluid velocity was determined by the steepest descent method to calculate the hydraulic permeability. Further, a laboratory experimental setup was built to measure the hydraulic permeability of screened dry sand with different grain diameters. The measured results were in a good agreement with the predictions by other theoretical models. Finally, the effects of the filling height and immersion depth of the capillary tube on the test accuracy were discussed. The present method can also be applied for other porous materials with the grain diameter of 0.1-0.6mm.

  9. Capillary permeability is increased in normo- and microalbuminuric Type I diabetic patients : amelioration by ACE-inhibition

    Jager, J; Hoogenberg, K; Dullaart, RPF; Smit, AJ


    Background Capillary leakage of sodium-fluorescein (NaF) in the skin reflects capillary permeability and may be a marker of diabetes-associated microcirculatory abnormalities. Design We evaluated transcapillary skin NaF leakage by fluorescence videodensitometry in 10 normoalbuminuric, 10 microalbumi

  10. Influence of clay and silica on permeability and capillary entry pressure of chalk reservoirs in the North Sea

    Røgen, Birte; Fabricius, Ida Lykke


    The permeability and capillary entry pressure of chalk reservoirs are controlled by their porosity and specific surface area. Measured permeabilities are in the range 0.025-5.3 mD and are successfully predicted by use of the Kozeny equation. In this paper we focus on the factors that control spec...




    SUMMARYIn this study, a simple, rapid and accurate capillary electrophoresis method has been developed for the determination of lactulose and mannitol in urine for estimating the intestinal permeability. The urine samples were prepared to analyze by using solid phase extraction. For analysis a background electrolyte (BGE) consisted of 6 mmol/L sorbic acid, 1.25mmol/L hexadecyltrimethylammoniumbromide (HDTMA), 50 mmol/L LiOH (pH 12.5) was used. Separation was performed at -5 kV over 20 min wit...

  12. Pulmonary oxygen toxicity: demonstration of abnormal capillary permeability using contrast-enhanced MRI

    An animal model of oxygen-induced pulmonary injury was used to assess the potential of contrastenhanced MRI to identify and quantify abnormal capillary permeability. Spargue-Dawley rats were exposed to 100% oxygen for 48 h (n=5) or 60 h (n=9). Axial spinecho MR images were acquired in intubated, anesthetized rats with ECG-gating (TR 400; TE 6) immediately or 7 days after the cessation of oxygen exposure. Polylysine-Gd-DTPA, was then given intravenously and the lungs were serially imaged for 42 to 47 min. Pulmonary enhancement was stable in rats exposed to 48 h of oxygen, and in rats exposed to 60 h of oxygen and given 7 days to recover. However, animals exposed to 100% oxygen for 60 h without a period of recovery showed a progressive increase in lung signal intensity for 15 min after polylysine-Gd-DTPA. Pleural effusions also showed progressively increasing signal. Given the assumption of our kinetic model, MRI following intravenous administration of polylysine-Gd-DTPA can be used to quantitate changes in capillary integrity induced by hyperoxia, including acute capillary leakiness and return to normal endothelial integrity with recovery from hyperoxic injury. (UWA)

  13. The influence of low-permeability cap on capillary pressure during pumping in unconfined aquifer

    黄辉; 钱家忠; 匡星星; 陈冰宇; 马雷; 吴亚楠


    The pumping test in an unconfined aquifer with and without a low-permeability soil was studied experimentally to reveal the influence of the negative air pressure (NP) caused by the upper layer on the water content(w), the water pressure(Pw), as well as on the capillary pressure(Pc). The study demonstrates that the NP generated in the vadose zone during pumping in the capper aquifer has a significant influence onw,wP andPc. ThecP obtained from the capped aquifer is smaller than that without the upper layer. After the NP reaches a peak, the influence of the NP onPc is gradually declined as the air inflows through the upper layer which makes the NP gradually return to zero. When the air pressure returns to the atmospheric pressure,Pc in the vadose zone is only correlated withPw, the same as the case with no upper layer.

  14. Increased pulmonary alveolar-capillary permeability in patients at risk for adult respiratory distress syndrome

    Two methods for predicting adult respiratory distress syndrome (ARDS) were evaluated prospectively in a group of 81 multitrauma and sepsis patients considered at clinical high risk. A popular ARDS risk-scoring method, employing discriminant analysis equations (weighted risk criteria and oxygenation characteristics), yielded a predictive accuracy of 59% and a false-negative rate of 22%. Pulmonary alveolar-capillary permeability (PACP) was determined with a radioaerosol lung-scan technique in 23 of these 81 patients, representing a statistically similar subgroup. Lung scanning achieved a predictive accuracy of 71% (after excluding patients with unilateral pulmonary contusion) and gave no false-negatives. We propose a combination of clinical risk identification and functional determination of PACP to assess a patient's risk of developing ARDS

  15. A FORTRAN program for interpretation of relative permeability from unsteady-state displacements with capillary pressure included

    Udegbunam, E.O.


    This paper presents a FORTRAN program for the determination of two-phase relative permeabilities from unsteady-state displacement data with capillary pressure terms included. The interpretative model employed in this program combines the simultaneous solution of a variant of the fractional flow equation which includes a capillary pressure term and an integro-differential equation derived from Darcy's law without assuming the simplified Buckley-Leverett flow. The incorporation of capillary pressure in the governing equations dispenses with the high flowrate experimental requirements normally employed to overcome capillarity effects. An illustrative example is presented herein which implements this program for the determination of oil/water relative permeabilities from a sandstone core sample. Results obtained compares favorably with results previously given in the literature. ?? 1991.

  16. Clinical studies of alveolar-capillary permeability using technetium-99m DTPA aerosol

    Soluble radioaerosols such as technetium-99m diethylene triamine pentacetate (DTPA) permit simple quantitative studies of alveolar-capillary permeability to be performed, since the submicronic aerosols are deposited mainly at the lung periphery and are cleared across the alveolar-capillary membrane. Regional alterations in permeability can also be noted using this radionuclide technique. We have measured the pulmonary epithelial permeability in normal subjects and the alteration in smokers, glue-sniffers, patients with inhalation burns, chronic obstructive pulmonary disease (COPD) and patients with lung metastases from thyroid cancer treated with radioiodine 131I. In the normal volunteers, the time taken for 50% of inhaled 99mTc DTPA to be cleared from the lungs (T1/2) was 66 minutes±1 sd of 12 mins. The smokers had a mean T1/2 of 20 mins±1 sd 4 min. In the hard-core glue-sniffing group, the majority were smokers who had stopped smoking and glue-sniffing for periods varying from 1 day to 42 days, and it was possible to note the changes in clearance times against period of abstinence. In the patients with inhalation burns, there was change in lung clearance arising from pulmonary epithelial damage; these patients showed increased rate of clearance (short T1/2) with mean T1/2 of 36 min±1 sd of 11 mins, while the retention images revealed regional lung damage in moderately severe inhalation burns. Twenty-four patients with COPD had inhalation scans done with Tc-99m tin colloid radioaerosol, and these images were compared with the perfusion lung scans done with 99mTc macroaggregated albumin (MAA); in general the perfusion images matched the defects noted in the inhalation scans. The 99mTc DTPA clearance rate in these patients was normal i.e. T1/2=78±14 mins. In the thyroid cancer patients with lung metastases, who had high doses of radioiodine treatment, the T1/2 values were normal or prolonged slightly, mean T1/2=76 min±23. (author)

  17. Permeability estimation of porous media by using an improved capillary bundle model based on micro-CT derived pore geometries

    Jiang, Lanlan; Liu, Yu; Teng, Ying; Zhao, Jiafei; Zhang, Yi; Yang, Mingjun; Song, Yongchen


    The purpose of this work is to develop a permeability estimation method for porous media. This method is based on an improved capillary bundle model by introducing some pore geometries. We firstly carried out micro-CT scans to extract the 3D digital model of porous media. Then we applied a maximum ball extraction method to the digital model to obtain the topological and geometrical pore parameters such as the pore radius, the throat radius and length and the average coordination number. We also applied a random walker method to calculate the tortuosity factors of porous media. We improved the capillary bundle model by introducing the pore geometries and tortuosity factors. Finally, we calculated the absolute permeabilities of four kinds of porous media formed of glass beads and compared the results with experiments and several other models to verify the improved model. We found that the calculated permeabilities using this improved capillary bundle model show better agreement with the measured permeabilities than the other methods.

  18. Influence of clay and silica on permeability and capillary entry pressure of chalk reservoirs in the North Sea

    Røgen, Birte; Fabricius, Ida Lykke


    The permeability and capillary entry pressure of chalk reservoirs are controlled by their porosity and specific surface area. Measured permeabilities are in the range 0.025-5.3 mD and are successfully predicted by use of the Kozeny equation. In this paper we focus on the factors that control...... specific surface area. Fifty-nine Tor and Ekofisk Formation chalk samples from five North Sea chalk reservoirs were investigated. All contain quartz and clay minerals, most commonly kaolinite and smectite, with trace amounts of illite. The contents of calcite and quartz are inversely correlated and both...

  19. Effect of Heat Transfer on Oscillatory Flow of Blood through a Permeable Capillary

    Aniruddha Sinha


    Full Text Available Of concern in the paper is a study on heat transfer in the unsteady magnetohydrodynamic (MHD flow of blood through a porous segment of a capillary subject to the action of an external magnetic field. Nonlinear thermal radiation and velocity slip condition are taken into account. The time-dependent permeability and suction velocity are considered. The governing non-linear patial differential equations are transformed into a system of coupled non-linear ordinary differential equations using similarity transformations and then solved numerically using Crank-Nicolson scheme. The computational results are presented in graphical/tabular form and thereby some theoretical predictions are made with respect to the hemodynamical flow of blood in a hyperthermal state under the action of a magnetic field. Effects of different parameters are adequately discussed. The results clearly indicate that the flow is appreciably influenced by slip velocity and also by the value of the Grashof number. It is also observed that the thermal boundary layer thickness enhances with increase of thermal radiation.

  20. Comparison of histamine and hyperosmotic arabinose infusion on brain capillary permeability to hydrophilic solutes

    The effect of bilateral intracarotid infusion of histamine (HA) on capillary permeability-surface area products (PS) of two metabolically inert tracers was determined and compared to that of L(+)arabinose (ARAB) in rat brain. Ringer's solution alone, or with 1 mg/kg HA diphosphate or 1.6M ARAB added, was infused (0.9 ml over 0.5 min) into each external carotid artery (CA). Five minutes later, a bolus of 14C-sucrose and 3H-L-glucose was injected i.v. Estimates of PS for both tracers were computed by the method of Ohno et al after brain concentration was corrected for tracer within cerebral blood vessels. Brain blood volume, based on the 14C-dextran space, was the same (.016 ml/g) in discrete cortical and midbrain regions of all rats except those treated with ARAB. The latter yielded .033 ml/g, presumably due to dextran extravasation. Infusion of ARAB, HA and Ringer's increased the PS's of sucrose and L-glucose by 10x, 8x, and 3x in brain regions perfused by the internal CA's. The ratio, PS-sucrose/PS-L-glucose was unchanged by any treatment. Both ARAB and HA caused transient falls in arterial pressure, but only ARAB caused deaths (3 of 9 rats). While as effective as ARAB in opening the blood-brain barrier, HA may be safer than hyperosmotic shock to enhance delivery of chemotherapeutic agents to brain tumors

  1. Myocardial capillary permeability after regional ischemia and reperfusion in the in vivo canine heart. Effect of superoxide dismutase

    Svendsen, Jesper Hastrup; Bjerrum, P J; Haunsø, S


    This study assesses the effect of the superoxide anion scavenger superoxide dismutase on myocardial capillary permeability-surface area (PS) products for small hydrophilic molecules after ischemia and reperfusion. Open-chest dogs underwent a 20-minute occlusion of the left anterior descending...... start of reperfusion. In 13 dogs, no scavenger treatment was given (nonprotected control group), whereas eight dogs were treated systemically with 15,000 units/kg superoxide dismutase during 1 hour, starting 20 minutes before ischemia. In the control group, three dogs developed reperfusion ventricular...... fraction and PS values seen in the control group suggest an increased capillary permeability after ischemia and reperfusion. Superoxide anions seem to participate, directly or indirectly, in this response....

  2. Contrast-enhanced magnetic resonance imaging estimation of altered capillary permeability in experimental mammary carcinomas after x-irradiation

    Dynamic magnetic resonance imaging (MRI) enhanced with a macromolecular contrast medium, albumin-(Gd-DTPA)35, was used to detect changes in microvascular characteristics in R3230 mammary adenocarcinomas induced by x-irradiation. Tumors were implanted in either flank in nine rats. One of the tumors was exposed to single-dose x-irradiation (30 Gy) 3 days before MRI. The contralateral control tumor was shielded from irradiation. Capillary permeability to macromolecular contrast medium in irradiated tumors was elevated significantly (P -1 cm-3 compared with 0.121 ± .011 mL hr-1 cm-3 for the nonirradiated tumors. This radiation-induced increase in permeability was corroborated using a macromolecular Evans blue-protein complex measured in the same tumors using an invasive spectrophotometric technique. Dynamic MRI-enhanced with macromolecular contrast medium permits noninvasive quantitative estimates of capillary permeability in tumors, with and without x-irradiation. Because the transendothelial permeability for macromolecular solutes likely influences tumoral accumulation of macromolecular chemotherapeutic agents, this noninvasive technique may prove to be clinically useful in tailoring tumor treatment programs which combine radiation and chemotherapy. 51 refs., 4 figs., 1 tab

  3. Simultaneous determination of capillary pressure and relative permeability curves from core-flooding experiments with various fluid pairs

    Pini, Ronny; Benson, Sally M.


    Capillary pressure and relative permeability drainage curves are simultaneously measured on a single Berea Sandstone core by using three different fluid pairs, namely gCO 2/water, gN2/water and scCO 2/brine. This novel technique possesses many of the characteristics of a conventional steady-state relative permeability experiment and consists of injecting the nonwetting fluid at increasingly higher flow rates in a core that is initially saturated with the wetting phase, while observing fluid saturations with a medical x-ray CT scanner. Injection flow rates (0.5-75 mL/min) are varied so as to generate a large range of capillary pressures (up to 18 kPa), whereas fluid-pairs and experimental conditions are selected in order to move across a range interfacial tension values (γ12=40-65 mN/m), while maintaining a constant viscosity ratio (μw/μnw ≈30). Moreover, these experiments, carried out at moderate pressures (P=2.4 MPa and T=50°C), can be compared directly with results for gas/liquid pairs reported in the literature and they set the benchmark for the experiment at a higher pressure (P=9 MPa and T=50°C), where CO 2 is in the supercritical state. Contrary to some prior investigations, from these experiments we find no evidence that the scCO 2/brine system behaves differently than any of these other fluid pairs. At the same time, capillary pressure data show a significant (but consistent) effect of the different values for the interfacial tension. The fact that the three different fluid pairs yield the same drainage relative permeability curve is consistent with observations in the petroleum literature. Additionally, the observed end-point values for the relative permeability to the nonwetting phase (kr,nw ≈0.9) and the corresponding irreducible water saturations (Sw,irr ≈0.35) suggest that water-wet conditions are maintained in each experiment. The reliability of the measured relative permeability curves is supported by the very good agreement with data from

  4. Dynamic 99mTc-DTPA radioaerosol lung scanning for the evaluation of alveolar-capillary barrier permeability

    Pulmonary clearance of small droplet 99mTc-DTPA radioaerosol was studied in 100 patients (12 normal subjects, N; 10 asymptomatic healthy smoker, FA; 31 patients with interstitial lung diseases, IP; 47 patients with chronic obstructive lung disease, BPCO). The first seven minutes of clearance were described with the function At=Ao*exp(-K*t) and the time constant K was considered representative of the 99mTc-DTPA clearance rate and hence of the alveolar-capillary barrier permeability. Groups FA, IP and BPCO showed a significant (p99mTc-DTPA dynamic lung scanning is an easy, non-invasive method to assess derangements of alveolar-capillary barrier permeability secondary to epithelial damage; 2) permeability increase is a very early effect of cigarette smoke damafe to the epithelium; 3) other mechanisms of epithelial injury are present in diffuse lung disease; 4) while the clinical role of this new pathophysiological test is not yet clear, it is likely that it may become a very early marker of pulmonary epithelial damage in diffuse lung disease

  5. Cerebral extraction of N-13 ammonia: its dependence on cerebral blood flow and capillary permeability, surface area product

    13N-labeled ammonia was used to investigate: (1) the cerebral extraction and clearance of ammonia; (2) the mechanicsm by which capillaries accommodate changes in cerebral blood flow (CBF); and (3) its use for the measure of CBF. This was investigated by measuring the single pass extraction of 13NH3 in rhesus monkeys during P/sub a/CO2 induced changes in CBF, and with dog studies using in vitro tissue counting techniques to examine 13NH3 extraction in gray and white matter, mixed tissue, and cerebellum during variations in CBF produced by combinations of embolization, local brain compression, and changes in P/sub a/CO2. The single pass extraction fraction of 13NH3 varied from about 70 to 20% over a CBF range of 12 to 140cc/min/100gms. Capillary permeability-surface area product (PS) estimates from this data and the dog experiments show PS increasing with CBF. The magnitude and rate of increase in PS with CBF was highest in gray matter > mixed tissue > white matter. Tissue extraction of 13NH3 vs CBF relationship was best described by a unidirectional transport model in which CBF increases by both recruitment of capillaries and by increases of blood velocity in open capillaries. Glutamine synthetase, which incorporates 13NH3 into glutamine, appears to be anatomically located in astrocytes in general and specifically in the astrocytic pericapillary end-feet that are in direct contact with gray and white matter capillaries. The net 13NH3 extraction subsequent to an i.v. injection increases nonlinearly with CBF. Doubling or halving basal CBF produced from 40 to 50% changes in the 13N tissue concentrations with further increases in CBF associated with progressively smaller changes in 13N concentrations. 13NH3 appears to be a good tracer for the detection of cerebral ischemia with positron tomography but exhibits a poor response at high values of CBF

  6. Cysteinyl Leukotriene Receptor Antagonists Inhibit Tumor Metastasis by Inhibiting Capillary Permeability

    Nozaki, Masako; Yoshikawa, Masanobu; Ishitani, Kunihiko; Kobayashi, Hiroyuki; HOUKIN, KIYOHIRO; Imai, Kohzoh; Ito, Yoichiro; Muraki, Takamura


    We explored the possibility of the cysteinyl leukotriene receptor antagonists, pranlukast and montelukast, preventing tumor cell migration through both cerebral and peripheral capillaries. To study tumor cell migration through brain capillaries, male Fisher rats were cannulated via the cisterna magna under pentobarbital anesthesia. RCN9 cells labeled with a fluorescent marker PKH67 were intravenously administered following arachidonic acid administration into the subarachnoid space, and speci...

  7. Relative permeability hysteresis and capillary trapping characteristics of supercritical CO2/brine systems: An experimental study at reservoir conditions

    Akbarabadi, Morteza; Piri, Mohammad


    We present the results of an experimental study on the effects of hysteresis on capillary trapping and relative permeability of CO2/brine systems at reservoir conditions. We performed thirty unsteady- and steady-state drainage and imbibition full-recirculation flow experiments in three different sandstone rock samples, low- and high-permeability Berea and Nugget sandstones. The experiments were carried out at various flow rates with both supercritical CO2 (scCO2)/brine and gaseous CO2 (gCO2)/brine fluid systems. The unsteady-state experiments were carried out with a wide range of flow rates to establish a broad range of initial brine saturations (Swi). This allowed investigation of the sensitivity of residual trapped CO2 saturation (S) to changes in Swi. The values were successfully compared with those available in the literature. For a given Swi, the trapped scCO2 saturation was less than that of gCO2 in the same sample. This was attributed to brine being less wetting in the presence of scCO2 than in the presence of gCO2. Post-imbibition dissolution of trapped CO2 and formation of dissolution front was also investigated. During the steady-state experiments, scCO2 and brine were co-injected with monotonically increasing or decreasing fractional flows to perform drainage and imbibition processes. We carried out seven sets of steady-state flow tests with various trajectories generating a comprehensive group of relative permeability hysteresis curves. The scanning curves revealed distinct features with potentially important implications for storage of scCO2 in geological formations. For both series of experiments, the ratio of S to initial CO2 saturation (1- Swi) was found to be much higher for low initial CO2 saturations. The results indicate that very promising fractions (about 49 to 83%) of the initial CO2 saturation can be stored through capillary trapping.

  8. Myocardial capillary permeability for small hydrophilic indicators during normal physiological conditions and after ischemia and reperfusion

    Svendsen, Jesper Hastrup


    including microvascular alterations. In open chest dogs transitory increases in capillary extraction fraction and PdS for small hydrophilic solutes were seen following 20 minutes of regional myocardial ischemia and reperfusion. This response could be inhibited by treatment directed against superoxide...... injected indicator molecules in an extracted and a transmitted fraction of molecules. In open chest dog hearts measurements performed during normal physiological conditions gave mean capillary extraction values of 43.5-47.5% and the corresponding calculated PdS values were 47.1 - 57.5 ml.(100g.min)-1. From...

  9. Evaluation of two-phase relative permeability and capillary pressure relations for unstable displacements in a pore network

    Dehoff, Karl J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Oostrom, Martinus [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhang, Changyong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Grate, Jay W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)


    A series of displacement experiments was conducted using five wetting-nonwetting immiscible fluid pairs in a homogenous and uniform pore network. The micromodel was initially saturated with either polyethylene glycol 200 (PEG) or water as a wetting fluid, which was subsequently displaced by a nonwetting fluid (dodecane, hexadecane, or mineral oil) at different flow rates. The experiments were designed to allow determinations of nonwetting fluid relative permeabilities ( ), fluid saturations ( ), and capillary pressure heads ( ). In the displacements, nonwetting fluid saturations increased with increasing flow rates for all five fluid pairs, and viscous fingering, capillary fingering, and stable displacement were observed. Viscous fingering occurred when PEG was displaced by either dodecane or hexadecane. For the water displacements, capillary fingers were observed at low capillary numbers. Due to unstable fingering phenomena, values for the PEG displacements were smaller than for the water displacements. A fitting exercise using the Brooks-Corey (1964) relationship showed that the fitted entry pressure heads are reasonably close to the computed entry pressure head. The fitted pore geometry factor, Sn values for the displacements are considerably lower than what is expected for displacements in homogeneous, highly uniform, porous systems, demonstrating the impact of unstable displacement on the apparent value of Sn. It was shown that a continuum-based multiphase model could be used to predict the average behavior for wetting fluid drainage in a pore network as long as independently fitted - and - relations are used. The use of a coupled approach through the Brooks-Corey pore geometry factor underpredicts observed values.

  10. A Relatioship between Capillary Pressure and Permeability as Revealed by a Pore Network Model

    Čapek, P.; Hejtmánek, Vladimír

    Praha : Process Engineering Publisher, 2004, s. 857. ISBN 80-86059-40-5. [International Congress of Chemical and Process Engineering CHISA 2004 /16./. Praha (CZ), 22.08.2004-26.08.2004] Institutional research plan: CEZ:AV0Z4072921 Keywords : pore network model * capillary pressure curve * slip flow Subject RIV: CF - Physical ; Theoretical Chemistry

  11. Upper and lower bounds on capillary permeability ratios of Cr-EDTA to cyanocobalamin in rat hindquarters.

    Haraldsson, B; Rippe, B


    The single injection indicator dilution technique, often used for assessing capillary permeability, was employed for estimations of the equivalent pore radius of skeletal muscle microvessels according to the theory of restricted diffusion. There are, however, certain important sources of error that must be considered in order to allow conclusions regarding the degree of restricted diffusion. In this study, we have recalculated previously published data in order to minimize the effect of heterogeneity of the second kind, i.e. a transit-time dependence of the fractional extraction values. The method used makes it possible to calculate reliable intervals of confidence for the permeability surface area products, and hence for the permeability surface area product-ratios (and equivalent pore radius), taking into account the maximal theoretical impact of back diffusion on measured extraction data. After correction for transit-time dependent effects of heterogeneity, the permeability surface area product-ratio of Cr-EDTA to cyanocobalamin (vit. B12) from 48 measurements in eight rats was found to have a theoretical 'upper bound' of 2.63 +/- 0.06 and a lower bound of 2.10 +/- 0.07, corresponding to an equivalent pore radius of 60 to 109 A. This minimum pore radius estimate was even further reduced by corrections for plasma flow dependent reductions in overall extraction fraction (heterogeneity of the first kind) to 45 A, whereas the upper bound on pore radius was reduced to 60 A. These data strongly support the presence of marked restricted diffusion of small solutes in the maximally vasodilated rat hindquarter microvasculature. PMID:1772031

  12. An experimental study of relative permeability hysteresis, capillary trapping characteristics, and capillary pressure of CO2/brine systems at reservoir conditions

    Austin Suthanthiraraj, Pearlson Prashanth

    We present the results of an extensive experimental study on the effects of hysteresis on permanent capillary trapping and relative permeability of CO2/brine and supercritical (sc)CO2+SO2/brine systems. We performed numerous unsteady- and steady-state drainage and imbibition full-recirculation flow experiments in three different sandstone rock samples, i.e., low and high-permeability Berea, Nugget sandstones, and Madison limestone carbonate rock sample. A state-of-the-art reservoir conditions core-flooding system was used to perform the tests. The core-flooding apparatus included a medical CT scanner to measure in-situ saturations. The scanner was rotated to the horizontal orientation allowing flow tests through vertically-placed core samples with about 3.8 cm diameter and 15 cm length. Both scCO2 /brine and gaseous CO2 (gCO2)/brine fluid systems were studied. The gaseous and supercritical CO2/brine experiments were carried out at 3.46 and 11 MPa back pressures and 20 and 55°C temperatures, respectively. Under the above-mentioned conditions, the gCO2 and scCO2 have 0.081 and 0.393 gr/cm3 densities, respectively. During unsteady-state tests, the samples were first saturated with brine and then flooded with CO2 (drainage) at different maximum flow rates. The drainage process was then followed by a low flow rate (0.375 cm 3/min) imbibition until residual CO2 saturation was achieved. Wide flow rate ranges of 0.25 to 20 cm3/min for scCO2 and 0.125 to 120 cm3min for gCO2 were used to investigate the variation of initial brine saturation (Swi) with maximum CO2 flow rate and variation of trapped CO2 saturation (SCO2r) with Swi. For a given Swi, the trapped scCO2 saturation was less than that of gCO2 in the same sample. This was attributed to brine being less wetting in the presence of scCO2 than in the presence of gCO 2. During the steady-state experiments, after providing of fully-brine saturated core, scCO2 was injected along with brine to find the drainage curve and as

  13. Tissue to plasma capillary permeability of 131I-albumin in the perfused rabbit ear

    The tissue to plasma transfer of 131I-albumin was recorded in perfused rabbit ears (n = 6) following equilibration for 24 hr. 125I-fibrinogen served as the plasma marker, and was introduced intravenously 15 min before clamping. The ears were rollerpump perfused with isotonic diluted plasma at a constant rate of (mean ± SD) 5.1 ± 1.5 ml (min.100 g)-1. The mean extravascular albumin distribution volume was 12.4 ± 1.1 ml.100 g-1, and the fibrinogen volume (plasma volume in tissue) was 3.1 ± 0.4 ml.100 g-1 as determined from biopsies of the contralateral ear. The initial transfer of albumin was marked, and occurred at rates corresponding to a unidirectional clearance (Cl(0)) of 0.068 ± 0.012 ml (min.100 g)-1. However, with a reduction of mean interstitial albumin tracer content of no more than 4%, net transport decreased to reach slowly declining levels 5 to 10 times lower within 10 min of continued perfusion. The decrease was considered due to rapid exhaustion of a small interstitial pool of tracer immediately adjacent to the exchange vessel membrane, followed by an increasingly retarded outwash from more distant areas. The results suggest a bimodal structural resistance to albumin movement: a relatively low resistance in the capillary membrane, and a considerable restriction to albumin transport located within the interstitial space

  14. An Integrated Capillary, Buoyancy, and Viscous-Driven Model for Brine/CO2Relative Permeability in a Compositional and Parallel Reservoir Simulator

    Kong, X.


    The effectiveness of CO2 storage in the saline aquifers is governed by the interplay of capillary, viscous, and buoyancy forces. Recent experimental study reveals the impact of pressure, temperature, and salinity on interfacial tension (IFT) between CO2 and brine. The dependence of CO2-brine relative permeability and capillary pressure on pressure (IFT) is also clearly evident in published experimental results. Improved understanding of the mechanisms that control the migration and trapping of CO2 in subsurface is crucial to design future storage projects that warrant long-term and safe containment. Simulation studies ignoring the buoyancy and also variation in interfacial tension and the effect on the petrophysical properties such as trapped CO2 saturations, relative permeability, and capillary pressure have a poor chance of making accurate predictions of CO2 injectivity and plume migration. We have developed and implemented a general relative permeability model that combines effects of pressure gradient, buoyancy, and IFT in an equation of state (EOS) compositional and parallel simulator. The significance of IFT variations on CO2 migration and trapping is assessed.

  15. Isotopic test of capillary permeability to albumin in diabetic patients: effects of hypertension, microangiopathy, and duration of diabetes

    Capillary permeability to albumin (CPA) was studied by performing an isotopic noninvasive test with venous compression on 87 nonselected diabetics with no edema, no cardiac failure, and no peripheral vascular disease. Excessive albumin retention (AR greater than or equal to 8%) ten minutes after removal of the compression was found in 27 patients (31%). The radioactivity disappearance curve was then analyzed using the Fast Fourier Transform (FFT). An abnormal isotopic CPA test was thus found in at least 45 out of the 87 patients. The prevalence of an abnormal test was not different in type 1 and type 2 diabetics. We studied the independent effects of hypertension, presence of specific clinical signs of microangiopathy (retinopathy and/or significant proteinuria), and duration of diabetes. Among diabetics free of specific clinical signs of microangiopathy, the prevalence of an AR greater than or equal to 8% was significantly higher in those with hypertension (11/19) than in those with normal blood pressure (2/28) and in nondiabetic hypertensive patients (0/16). Among normotensive diabetics, the prevalence of an abnormal test was higher, but not significantly, in patients with specific clinical signs of microangiopathy (8/11) than in those free of them (7/18). Seven normotensive diabetics without specific clinical signs of microangiopathy had an abnormal test; five of them had had diabetes for more than five years. The prevalence of diabetes of more than five years duration was significantly higher in patients with an abnormal test (35/45) than in normotensive diabetics free of specific clinical signs of microangiopathy with a normal test (4/11)

  16. Measurement of the increase in the capillary permeability in skin with Evans blue labelled with iodine-125 or 131

    The quantitative evaluation of bradykinin and histamine with Evans blue labelled with iodine -125 or 131 is described. The activity upon vascular permeability was performed in the abdominal wall of rats injecting intravenously solution of labelled Evans blue and 0,1 ml of vasoactive drugs solution intradermally. Skin discs were cut with circular punch for external counting, quantitative results being compared with control discs. By using this method, satisfactory log dose-reponse curves were obtained for bradykinin and histamine that followed the general trend of S - shaped curves

  17. Unilateral renal ischaemia in rats induces a rapid secretion of inflammatory markers to renal lymph and increased capillary permeability.

    Bivol, Liliana Monica; Iversen, Bjarne Magnus; Hultström, Michael; Wallace, Paal William; Reed, Rolf Kåre; Wiig, Helge; Tenstad, Olav


    A better understanding of the inflammatory process associated with renal ischaemia-reperfusion (IR) injury may be clinically important. In this study we examined the role of the kidney in production of inflammatory mediators by analysing renal lymph after 30 min unilateral occlusion of renal artery followed by 120 min reperfusion, as well as the effect of IR on size selectivity for proteins in both glomerular and peritubular capillaries. All measured mediators increased dramatically in renal hilar lymph, plasma and renal cortical tissue samples and returned to control levels after 120 min reperfusion. The responses were differentiated; interleukin-1β, monocyte chemoattractant protein-1 and leptin were markedly increased in plasma before reperfusion, reflecting an extrarenal response possibly induced by afferent renal nerve activity from the ischaemic kidney. Tumour necrosis factor-α was the only mediator showing elevated lymph-to-plasma ratio following 30 min reperfusion, indicating that most cytokines were released directly into the bloodstream. The IR-induced rise in cytokine levels was paralleled by a significant increase in high molecular weight plasma proteins in both lymph and urine. The latter was shown as a 14- to 166-fold increase in glomerular sieving coefficient of plasma proteins assessed by a novel proteomic approach, and indicated a temporarily reduced size selectivity of both glomerular and peritubular capillaries. Collectively, our data suggest that cytokines from the ischaemic kidney explain most of the rise in plasma concentration, and that the locally produced substances enter the systemic circulation through transport directly to plasma and not via the interstitium to lymph. PMID:26584508

  18. Studies on the increase of capillary permeability in rat skin under the action of pyridoxal 5' phosphate

    The activity of pyridoxal 5'-phosphate (PLP) is described on the vascular permeability response, measured in the abdominal wall of rats from the amount of extravased Evans blue labelled with radioactive iodine 125 or 131. The PLP effect is related to histamine release as it has been showed by tha use of antihistaminics. An attempt has been made in order to correlate structure and biological activity by using PLP analogs. The intact molecule of PLP seems to be the proper active substance. The critical role of calcium in histamine release is discussed in relation to our observations. In the presence of high concentrations of calcium and lantanium, PLP fails to increase the vascular permeability; magnesium does not show any influence. The calcium mobilization produced by theophylline results in inhibition of the response. The course of the reaction between PLP and histamine in vitro was followed; the synthetic cyclic product is deprived of activity and does not interfere with the intrinsic effects of PLP and histamine. (Author)

  19. Adrenergic-induced enhancement of brain barrier system permeability to small nonelectrolytes: choroid plexus versus cerebral capillaries

    Acute hypertension induced by adrenergic agents opens up the blood-CSF barrier (choroid plexus) to nonelectrolyte and protein tracers. Sprague-Dawley adult rats anesthetized with ketamine were given an intravenous bolus of either epinephrine (10 micrograms/kg), phenylephrine (100 micrograms/kg), isoproterenol (10 micrograms/kg), or D,L-amphetamine (2 mg/kg). Tracers were injected simultaneously with test agents, and the animals killed 10 min later. Epinephrine raised MABP by 57 mm Hg, to a peak pressure of 160 mm Hg; and it increased the volume of distribution (Vd) of urea, mannitol, and 125I-bovine serum albumin in CSF by 1.5-, 2.7-, and 30-fold, respectively. There was enhanced uptake by lateral and fourth ventricle choroid plexuses, cerebral cortex, cerebellum, medulla, and thalamus. Phenylephrine also elevated MABP to 160 mm Hg, but it increased permeation of tracers into CSF (and several brain regions) to a lesser extent than epinephrine, attributable to protective vasoconstriction associated with alpha-agonist activity. Ratio analysis of Vd data provides evidence that augmented permeation of nonelectrolyte tracers in acute hypertension occurs predominantly by diffusion rather than vesicular transport. It is postulated that elevated MABP distends the central cores of choroid plexus villi and cerebral capillaries, with resultant stretching and opening of tight junctions in both barrier systems; with less hindrance to diffusion, urea and mannitol are cleared at rates closer to free diffusion. Neither isoproterenol (decreased MABP by 40 mm Hg) nor amphetamine (did not alter MABP) significantly opened the choroid plexus or blood-brain barrier to tracers

  20. Protective Effects of N-Acetyl Cysteine against Diesel Exhaust Particles-Induced Intracellular ROS Generates Pro-Inflammatory Cytokines to Mediate the Vascular Permeability of Capillary-Like Endothelial Tubes.

    Chia-Yi Tseng

    Full Text Available Exposure to diesel exhaust particles (DEP is associated with pulmonary and cardiovascular diseases. Previous studies using in vitro endothelial tubes as a simplified model of capillaries have found that DEP-induced ROS increase vascular permeability with rearrangement or internalization of adherens junctional VE-cadherin away from the plasma membrane. This allows DEPs to penetrate into the cell and capillary lumen. In addition, pro-inflammatory cytokines are up-regulated and mediate vascular permeability in response to DEP. However, the mechanisms through which these DEP-induced pro-inflammatory cytokines increase vascular permeability remain unknown. Hence, we examined the ability of DEP to induce permeability of human umbilical vein endothelial cell tube cells to investigate these mechanisms. Furthermore, supplementation with NAC reduces ROS production following exposure to DEP. HUVEC tube cells contributed to a pro-inflammatory response to DEP-induced intracellular ROS generation. Endothelial oxidative stress induced the release of TNF-α and IL-6 from tube cells, subsequently stimulating the secretion of VEGF-A independent of HO-1. Our data suggests that DEP-induced intracellular ROS and release of the pro-inflammatory cytokines TNF- α and IL-6, which would contribute to VEGF-A secretion and disrupt cell-cell borders and increase vasculature permeability. Addition of NAC suppresses DEP-induced ROS efficiently and reduces subsequent damages by increasing endogenous glutathione.

  1. Importance of the terminal α-amino group of bradykinin and some kynins on capillary permeability increase

    A simple and reliable method is described for the quantitative evaluation of vascular permeability increase induced by vasoactive drugs with Evans blue labelled with iodine-125 or 131. By using this method the importance of α-amino group of bradykinin (Bk), kallidin (Kd) and methionyl-kallidin (Met-Kd) on the biological activity were studied after reacting the kinins with pyridoxal 5'-phosphate followed by reduction with sodium borohydride. Phosphopyridoxyl-kinins were formed leaving free the guanidino groups. Aminoacid analysis of phosphopyridoxyl-kinin showed that the efficiency of the reaction was extremely good in the blockage of α-amino groups [phosphopyridoxyl-bradikinin (PP-Bk) = 98,8%, phosphopyridoxyl-kallidin (PP-Kd) = 95,2%, phosphopyridoxyl-methionyl-kallidin (PP-Met-Kd) = 98,0%. Log dose-response curves were obtained for Bk, Kd, Met-Kd, acetyl-bradykinin (Ac-Bk), PP-Bk, PP-Kd and PP-Met-Kd and the relative potencies calculated through the Lineweaver-Burk plots. The relative potencies were: PP-Bk about 16% the activity of Bk, Ac-Bk about 31% the activity of Bk, PP-Kd about 17% the activity of Kd, PP-Met-Kd about 12% the activity of Met-Kd. The results show that the terminal α-amino group of kinins is important in the mechanisms of biological activity. (Author)

  2. Effect of capillary pressure on water flooding development in low permeability reservoir%低渗透油藏毛管压力对水驱开发效果的影响



    The dynamic effect of capillary force during oil-water phase seepage in low permeability reservoir is crucial in two-phase flow mechanism and water flooding effect.The research on the rules helps to improve the water flooding development effect in this reservoir.This article presents the influential factors of dynamic effect of capillary force and dynamic capillary force,as well as impacts of dynamic capillary force,water injection intensity,well spacing on water flooding effects in low permeability reservoir.%低渗透油藏油水两相渗流过程中毛管力的动态效应是影响两相渗流机理及水驱油效果的重要因素,掌握其规律有助于提高这一特殊油藏的水驱开发效果。分析了低渗透油藏油水两相渗流中毛管力的动态效应以及动态毛管力的影响因素,以及动态毛管力、注水强度、井距等因素对低渗透油藏水驱油效果的影响。

  3. Measurement and evaluation of the relationships between capillary pressure, relative permeability, and saturation for surrogate fluids for laboratory study of geological carbon sequestration

    Mori, H.; Trevisan, L.; Sakaki, T.; Cihan, A.; Smits, K. M.; Illangasekare, T. H.


    Multiphase flow models can be used to improve our understanding of the complex behavior of supercritical CO2 (scCO2) in deep saline aquifers to make predictions for the stable storage strategies. These models rely on constitutive relationships such as capillary pressure (Pc) - saturation (Sw) and relative permeability (kr) - saturation (Sw) as input parameters. However, for practical application of these models, such relationships for scCO2 and brine system are not readily available for geological formations. This is due to the complicated and expensive traditional methods often used to obtain these relationships in the laboratory through high pressure and/or high-temperature controls. A method that has the potential to overcome the difficulty in conducting such experiments is to replicate scCO2 and brine with surrogate fluids that capture the density and viscosity effects to obtain the constitutive relationships under ambient conditions. This study presents an investigation conducted to evaluate this method. An assessment of the method allows us to evaluate the prediction accuracy of multiphase models using the constitutive relationships developed from this approach. With this as a goal, the study reports multiple laboratory column experiments conducted to measure these relationships. The obtained relationships were then used in the multiphase flow simulator TOUGH2 T2VOC to explore capillary trapping mechanisms of scCO2. A comparison of the model simulation to experimental observation was used to assess the accuracy of the measured constitutive relationships. Experimental data confirmed, as expected, that the scaling method cannot be used to obtain the residual and irreducible saturations. The results also showed that the van Genuchten - Mualem model was not able to match the independently measured kr data obtained from column experiments. Simulated results of fluid saturations were compared with saturation measurements obtained using x-ray attenuations. This

  4. Porosity, single-phase permeability, and capillary pressure data from preliminary laboratory experiments on selected samples from Marker Bed 139 at the Waste Isolation Pilot Plant. Volume 1 of 3: Main report, appendix A

    Three groups of core samples from Marker Bed 139 of the Salado Formation at the Waste Isolation Pilot Plant (WIPP) were analyzed to provide data to support the development of numerical models used to predict the long-term hydrologic and structural response of the WIPP repository. These laboratory experiments, part of the FY93 Experimental Scoping Activities of the Salado Two-Phase Flow Laboratory Program, were designed to (1) generate WIPP-specific porosity and single-phase permeability data, (2) provide information needed to design and implement planned tests to measure two-phase flow properties, including threshold pressure, capillary pressure, and relative permeability, and (3) evaluate the suitability of using analog correlations for the Salado Formation to assess the long-term performance of the WIPP. This report contains a description of the boreholes core samples, the core preparation techniques used, sample sizes, testing procedures, test conditions, and results of porosity and single-phase permeability tests performed at three laboratories: TerraTek, Inc. (Salt Lake City, UT), RE/SPEC, Inc. (Rapid City, SD), and Core Laboratories-Special Core Analysis Laboratory (Carrollton, TX) for Rock Physics Associates. In addition, this report contains the only WIPP-specific two-phase-flow capillary-pressure data for twelve core samples. The WIPP-specific data generated in this laboratory study and in WIPP field-test programs and information from suitable analogs will form the basis for specification of single- and two-phase flow parameters for anhydrite markers beds for WIPP performance assessment calculations

  5. Capillary permeability of 99mTc-DTPA and blood flow rate in the human myocardium determined by intracoronary bolus injection and residue detection

    Svendsen, Jesper Hastrup; Efsen, F; Haunsø, S


    .7 ml.(100 g.min)-1 (SD 13.0). Similar values of blood flow rate, capillary extraction fraction and the PS product were determined in 6 patients with localized coronary atheroma without hemodynamically significant coronary artery stenosis (25-50% luminal narrowing). The values for the regional...... myocardial blood flow rate in the human heart are in accordance with values obtained by other methods, and the PS product of 99mTc-DTPA is similar to results obtained in canine hearts. Localized coronary atheroma leading to insignificant coronary artery stenosis does not produce any measurable dysfunction of...

  6. Capillary saturation and desaturation.

    Hilfer, R; Armstrong, R T; Berg, S; Georgiadis, A; Ott, H


    Capillary desaturation experiments produce disconnected (trapped) ganglia of mesoscopic sizes intermediate between pore size and system size. Experimental evidence for interactions between these mesoscale clusters during desaturation is analyzed and discussed within the established microscopic and macroscopic laws of Newton, Young-Laplace, and Darcy. A theoretical expression for capillary number correlations is introduced that seems to have remained unnoticed. It expresses capillary desaturation curves in terms of stationary capillary pressures and relative permeabilities. The theoretical expression shows that the plateau saturation in capillary desaturation curves may in general differ from the residual nonwetting saturation defined through the saturation limit of the main hysteresis loop. Hysteresis effects as well as the difference between wetting and nonwetting fluids are introduced into the analysis of capillary desaturation experiments. The article examines experiments with different desaturation protocols and discusses the existence of a mesoscopic length scale intermediate between pore scale and sample scale. The theoretical expression is derived entirely within the existing traditional theory of two-phase flow in porous media and compared to a recent experiment. PMID:26764820

  7. Capillary saturation and desaturation

    Hilfer, R.; Armstrong, R. T.; Berg, S.; Georgiadis, A.; Ott, H.


    Capillary desaturation experiments produce disconnected (trapped) ganglia of mesoscopic sizes intermediate between pore size and system size. Experimental evidence for interactions between these mesoscale clusters during desaturation is analyzed and discussed within the established microscopic and macroscopic laws of Newton, Young-Laplace, and Darcy. A theoretical expression for capillary number correlations is introduced that seems to have remained unnoticed. It expresses capillary desaturation curves in terms of stationary capillary pressures and relative permeabilities. The theoretical expression shows that the plateau saturation in capillary desaturation curves may in general differ from the residual nonwetting saturation defined through the saturation limit of the main hysteresis loop. Hysteresis effects as well as the difference between wetting and nonwetting fluids are introduced into the analysis of capillary desaturation experiments. The article examines experiments with different desaturation protocols and discusses the existence of a mesoscopic length scale intermediate between pore scale and sample scale. The theoretical expression is derived entirely within the existing traditional theory of two-phase flow in porous media and compared to a recent experiment.

  8. 重症急性胰腺炎大鼠肝脏毛细血管渗漏的发生机理%Mechanism of Liver Capillary Permeability in Rats with Severe Acute Pancreatitis

    李洪森; 黄鹤光


    Objective To explore the mechanism of liver capillary permeability in rats with severe acute pancreatitis (SAP).Methods Totally 40 healthy Sprague-Dawley (SD) rats were randomly divided into two groups:sham operation (SO) group and SAP group, SAP group were divided into four subgroups according to sampling time (3 h, 6 h, 12 h, and 24 h).The model was established by injecting 5% sodium taurocholate retrogradely into pancreaticobiliary ducts.The changes of tumor necrosis factor-α (TNF-α), pathohistology, and tissue moisture content were compared among different groups.Liver occludin protein expression was analyzed by immunohistochemistry method, and occludin mRNA was measured by RT-PCR.Results There was no significant pathological changes of liver tissue in the SO group.Typical pathological changes of SAP, such as interstitial edema, vasodilatation, infiltration of inflammatory cells, were found in the SAP group.TNF-α level and tissue moisture content of each phase increased gradually, and the highest level appeared at 24 h within the observing period.The two above indicators at different time point in subgroups were significantly different from each other and higher than those in the SO group (P<0.05).In the SAP group, the expression of occludin and it's mRNA began to decrease at 3 h to the bottom at 6 h and rebounced significantly at 12 h, 24 h compared with those at 6 h (P<0.05), but still lower than those in the SO group (P<0.05).Conclusion Upregulation in TNF-α and subsequent downregulation in occludin protein and mRNA maybe strongly related to the severe liver capillary permeability in rats with SAP.%目的 探讨重症急性胰腺炎(SAP)大鼠肝脏毛细血管渗漏的发生机理.方法 40只SD大鼠采用完全随机法随机分为假手术(sham operation,SO)组和SAP组,SAP按不同的取材时间又分为3、6、12及24 h 4个亚组,每组8只.以胰胆管逆行注射5%牛磺胆酸钠建立SAP模型,观察各组肝脏组织病理改变,检

  9. Capillary electrophoresis

    After a short historical introduction, the different modes of separation in capillary electrophoresis are explained and illustrated by practical examples. In addition, the most important parameters that can be used to optimize the selectivity of the separation, are discussed. (author) 27 refs.; 8 figs

  10. Impacts on oil recovery from capillary pressure and capillary heterogeneities

    Bognoe, Thomas


    The main conclusions drawn from this thesis are; 7 scientific papers are published on a broad variety of subjects, and describes in detail the experiments and research treated in this thesis. Scientific research has been performed, investigating the subjects of capillary pressure and capillary heterogeneities from different angles. This thesis discusses the findings in this study and aims to illustrate the benefits of the results obtained for further development of other experiments, and/or even the industrial benefits in field development. The methods for wettability alteration have developed throughout the work. From producing heterogeneous wettability alterations, the methods have improved to giving both radial and lateral uniform wettability alterations, which also remains unaltered throughout the duration of the experimental work. The alteration of wettability is dependent on initial water saturation, flow rate, aging time and crude oil composition. Capillary pressure and relative permeability curves have been measured for core plugs at different wettabilities using conventional centrifuge methods. The trends observed are mostly consistent with theory. The production mechanisms of strongly and moderately water wet chalk has been investigated. At strongly water wet conditions in fractured chalk; the flow is governed by capillary forces, showing strong impact from the fractures. At moderately water wet conditions, the impact of the fractures are absent, and a dispersed water front is observed during the displacement. The oil recovery is about the same, at the two wettabilities. Fracture crossing mechanisms at the same wettability conditions have been mapped. And the observations are consistent with those of the water floods. During strongly water wet displacement, the fracture crossing is occurring once the inlet core has reached endpoint of spontaneous imbibition. At moderately water wet conditions the fracture crossing is less abrupt, and creation of wetting

  11. a Comprehensive Model for Capillary Pressure Difference across a Drop/bubble Flowing Through a Constricted Capillary

    Liang, Mingchao; Wei, Junhong; Han, Hongmei; Fu, Chengguo; Liu, Jianjun


    The capillary pressure is one of the crucial parameters in many science and engineering applications such as composite materials, interface science, chemical engineering, oil exploration, etc. The drop/bubble formation and its mechanisms that affect the permeability of porous media have steadily attracted much attention in the past. When a drop/bubble moves from a larger capillary to a smaller one, it is often obstructed by an additional pressure difference caused by the capillary force. In this paper, a comprehensive model is derived for the capillary pressure difference when a drop/bubble flows through a constricted capillary, i.e. a geometrically constricted passage with an abrupt change in radius. The proposed model is expressed as a function of the smaller capillary radius, pore-throat ratio, contact angle, surface tension and length of the drop/bubble in the smaller capillary. The model predictions are compared with the available experimental data, and good agreement is found between them.

  12. Capillary Micro-Flow Through a Fiber Bundle(Ⅰ)

    ZHU Ying-dan; WANG Ji-hui; TAN Hua; GAO Guo-qiang


    The present work considered the capillary micro-flow through a fiber bundle. The resin heights in the fiber bundle as a function of time were used to determine the experimental values of capillary pressure and the permeability by the nonlinear regression fitting method. The fitting curves showed a good agreement with experiments. However, these values of capillary pressure from short- time experiments were much lower than the theoretical results from the Yang-Laplace Equation. More accurate capillary pressure was predicted from the presented long-run experiment.

  13. Porosity, single-phase permeability, and capillary pressure data from preliminary laboratory experiments on selected samples from Marker Bed 139 at the Waste Isolation Pilot Plant. Volume 3 of 3: Appendices C, D, E, and F

    This volume contains the mineralogy, porosity, and permeability results from the Marker Bed 139 anhydrite specimens evaluated by TerraTek, Inc. for the Waste Isolation Pilot Plant. This volume also documents the brine recipe used by RE/SPEC, Inc., the parameter package submitted to Performance Assessment based on all the data, and a memo on the mixed Brooks and Corey two-phase characteristic curves

  14. Porosity, single-phase permeability, and capillary pressure data from preliminary laboratory experiments on selected samples from Marker Bed 139 at the Waste Isolation Pilot Plant. Volume 3 of 3: Appendices C, D, E, and F

    Howarth, S.M.; Christian-Frear, T.


    This volume contains the mineralogy, porosity, and permeability results from the Marker Bed 139 anhydrite specimens evaluated by TerraTek, Inc. for the Waste Isolation Pilot Plant. This volume also documents the brine recipe used by RE/SPEC, Inc., the parameter package submitted to Performance Assessment based on all the data, and a memo on the mixed Brooks and Corey two-phase characteristic curves.

  15. Experimental Investigation on Sandstone Rock Permeability of Pakistan Gas Fields

    Raza, Arshad; Bing, Chua Han; Nagarajan, Ramasamy; Hamid, Mohamed Ali


    Permeability is the ability of formation to produce hydrocarbon which is affected by compaction, pore size, sorting, cementation, layering and clay swelling. The effect of texture on permeability in term of grain size, sorting, sphericity, degree of cementing has been reported in literature. Also, the effect of permeability on capillary pressure, irreducible water saturation, displacement pressure and pore geometry constant has been studied separately. This preliminary study presents the experimental results of eight samples to understand the effect of similar factors of texture on permeability. With the knowledge of the results, it can be said that the effect of grain size, cementation, texture material, sphericity, and porosity can't be observed on permeability except sorting when less than ten samples are considered from different depositional environment. The results also show the impact of permeability on capillary pressure, irreducible water saturation, and displacement pressure and pore geometry index as similar as published in the literature.

  16. Differential Capillary Effect Model of Fabric and Its Application

    王其; 冯勋伟


    The concept of the differential capillary effect was presented by foreign scholars several years ago, and the principle was used to design sportswear fabrics with good wet permeability and good drying functions for famous sports teams. Because the differential capillary effect model was not established in theory,it was impossible to fulfill the best functions. In this paper, by setting up the differential capillary effect of fabric, the factors to influence wet permeability and drying functions of the model is discussed in theory, and the means to optimize the design of the fabric is presented and proven practically by the experiment. The optimum fabric with good permeability and good drying functions can be designed using the model at last.

  17. Capillary flow through heat-pipe wicks

    Eninger, J. E.


    Theoretical expressions are obtained for the capillary-pressure limit and permeability of a fibrous wick in terms of the porosity and fiber diameter. Hysteresis in capillary pressure is included through the introduction of an empirical hysteresis constant. A partial-saturation model based on the statistical distribution of local porosity requires an additional empirical constant, the standard deviation. The theory is compared to results of a beta-ray absorption experiment that measured the liquid content of a partially saturated wick and to results of permeability measurements on partially and fully saturated wicks. A simple wick-weighing experiment is described that yields values for the empirical hysteresis constant and the standard deviation. Theoretical results are used to design an optimum wick.

  18. Water block effects in low permeability gas reservoirs

    Gruber, N. G. [Core Laboratories Canada Ltd, Calgary, AB (Canada)


    The mechanism of permeability reduction as a result of extraneous fluid invasion was studied. Laboratory data showed that for water-wet reservoirs, areas of porosity where bound water exists, contribute little to permeability. Even in extremely low permeability cores, the effect of irreducible water saturation on gas permeability was only a 20 per cent reduction. These results led to the conclusion that permeability damage is only slightly worse in dessicated gas reservoirs than in gas reservoirs controlled by capillary pressure. Similarly, it was concluded that the primary mechanism of permeability loss due to water block is the blocking of macro pores; microporosity contributes little if any to permeability. 11 refs., 1 tab., 12 figs.

  19. The Effects of Alcohol Abuse on Pulmonary Alveolar-Capillary Barrier Function in Humans

    Burnham, Ellen L.; Halkar, Raghuveer; Burks, Marsha; Moss, Marc


    Aims: Alcohol abuse is associated with the development of the acute respiratory distress syndrome, a disorder characterized by abnormal alveolar-capillary permeability. We hypothesized that individuals with a history of alcohol abuse would have clinical evidence of abnormal alveolar-capillary permeability even in the absence of symptoms. This could contribute to their propensity for the development of this disorder. Methods: Thirty-three subjects with a history of alcohol abuse, but no other ...

  20. Ultrastructural localization of cholinergic muscarinic receptors in rat brain cortical capillaries

    Luiten, PGM; deJong, GI; VanderZee, EA; vanDijken, H; Dijken, H. van


    Cholinergic innervation of the cerebrovasculature is known to regulate vascular tone, perfusion rate and permeability of the microvascular wall. Notably the cholinergic innervation of cerebral capillaries is of interest since these capillaries form the blood-brain barrier. Although there is a genera

  1. Ultrastructural localization of cholinergic muscarinic receptors in rat brain cortical capillaries

    Luiten, PGM; DEJONG, GI; VANDERZEE, EA; vanDijken, H; van Dijken, H.


    Cholinergic innervation of the cerebrovasculature is known to regulate vascular tone, perfusion rate and permeability of the microvascular wall. Notably the cholinergic innervation of cerebral capillaries is of interest since these capillaries form the blood-brain barrier. Although there is a general consensus as to the presence of nicotinic and muscarinic receptors in the domain of the capillary wall, their precise anatomical position is unknown. The subcellular localization of muscarinic re...

  2. Effect of Implementing Three-Phase Flow Characteristics and Capillary Pressure in Simulation of Immiscible WAG

    Dale, Elisabeth Iren; Skauge, Arne


    The effect of including a three-phase representation of the flow parameters and capillary pressure has been investigated using a black oil simulator. The simulation approaches include the complexity of three-phase flow, relative permeability hysteresis, dynamic phase trapping functions and capillary pressure. A WAG simulation case was used to study the effect of three-phase flow parameters and capillary pressure on the size of the three-phase zone, breakthrough time of the inje...

  3. Relative permeability in dual porosity porous media

    Deghmoum, A. [SONATRACH CRD, Boumerdes (Algeria); Tiab, D. [Oklahoma Univ., Norman, OK (United States); Mazouzi, A. [SONATRACH PED (Algeria)


    One of the important factors in the field of reservoir simulation of dual-porosity systems is reliable relative permeability data. Laboratory limitations hinder measurements. The real behaviour of naturally fractures reservoirs is not reflected in the reservoir core samples, which as a rule originate from zones without induced or natural fractures. Therefore, it is commonly assumed that the relative permeability of a naturally fractured system is a straight line, which can cause errors. The authors undertook to conduct special core analyses on Berea outcrop core samples, to simulate fracture opening through the cutting of the samples to get different fracture apertures, to study the effects of dual porosity on the shape of capillary pressure curves, and to evaluate absolute and relative permeability, as they are affected by fracture opening. The correlation obtained between absolute permeability and fracture aperture was good, and capillary pressure curves permitted the observation of the effect of dual porosity. High residual oil saturation was present in the matrix, since the fractures became the easiest route for water flow, and this situation prevented the use of unsteady-state tests to measure relative permeability on the samples. Instead, the centrifuge technique was successfully used. A naturally fractured reservoir (NFR), the Tin Fouye Tabankort (TFT) reservoir in Algeria was selected to extend the findings. The site was principally selected due to the availability of naturally fractured cores and published data. Core observations, well test analysis and borehole imager tools were all TFT natural fracture indicators presented in the paper. Representative data of relative permeability was obtained by conducting a displacement test on a full diameter core to solve the laboratory limitations. The correlation between permeability and fracture opening was used to estimate the aperture of natural fractures in TFT reservoir. 17 refs., 2 tabs., 24 figs.

  4. Intramedullary capillary haemangioma.

    Kelleher, T


    Intramedullary capillary haemangioma is extremely rare and only four cases have been previously reported. We describe a further case, outlining the clinical, radiological, surgical and pathological features.

  5. Developments in permeable and low permeability barriers

    The concept of the reactive treatment zone whereby pollutants are attenuated as they move along a pathway in the ground has enabled a re-thinking of many of the concepts of containment. In particular it offers the potential for the control of the flux from a contaminated area by controlling the contaminant concentration in the pathway(s) as well as or instead of using a low permeability barrier. The paper outlines the basic concepts of the reactive treatment zone and the use of permeable and low permeability reactive systems. The paper then gives a case history of the installation of a permeable barrier using an in-situ reaction chamber

  6. Network Modelling of Capillary Pressure Curves, Permeability, and Diffusivity.

    Čapek, P.; Hejtmánek, Vladimír; Brabec, Libor; Zikánová, Arlette; Kočiřík, Milan


    Roč. 62, 18-20 (2007) , s. 5117-5122. ISSN 0009-2509 R&D Projects: GA ČR(CZ) GA203/05/0347 Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z40400503 Keywords : porous media * pore network model * stochastic reconstruction Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.775, year: 2007

  7. Reinforcing endothelial junctions prevents microvessel permeability increase and tumor cell adhesion in microvessels in vivo

    Bingmei M Fu; Jinlin Yang; Bin Cai; Jie Fan; Lin Zhang; Min Zeng


    Tumor cell adhesion to the microvessel wall is a critical step during tumor metastasis. Vascular endothelial growth factor (VEGF), a secretion of tumor cells, can increase microvessel permeability and tumor cell adhesion in the microvessel. To test the hypothesis that inhibiting permeability increase can reduce tumor cell adhesion, we used in vivo fluorescence microscopy to measure both microvessel permeability and adhesion rates of human mammary carcinoma MDA-MB-231 cells in post-capillary v...

  8. A multiple fractal model for estimating permeability of dual-porosity media

    Li, Bo; Liu, Richeng; Jiang, Yujing


    A multiple fractal model that considers the fractal properties of both porous matrices and fracture networks is proposed for the permeability of dual-porosity media embedded with randomly distributed fractures. In this model, the aperture distribution is verified to follow the fractal scaling law, and the porous matrix is assumed to comprise a bundle of tortuous capillaries that also follow the fractal scaling law. Analytical expressions for fractal aperture distribution, total flow rate, total equivalent permeability, and dimensionless permeability are established, where the dimensionless permeability is defined as the ratio of permeability of the porous matrices to that of the fracture networks. The dimensionless permeability is closely correlated to the structural parameters (i.e., α, θ, Dtf, Dtp, De, Dp, emax, λmax) of the dual-porosity media, and it is more sensitive to the fractal dimension for the size distribution of fracture aperture than to that for the size distribution of pore/capillary diameter. The maximum pore/capillary diameter has a greater impact on the dimensionless permeability than that of the maximum fracture aperture. The dimensionless permeability of fracture networks constructed by the fractal aperture distribution has close values with those of models with lognormal aperture distribution. The proposed multiple fractal model does not involve any empirical constants that do not have clear physical meanings, which could serve as a quick estimation method for assessing permeability of dual-porosity media.

  9. CO2 Capillary-Trapping Processes in Deep Saline Aquifers

    Gershenzon, Naum I.; Soltanian, Mohamadreza; Ritzi, Robert W., Jr.; Dominic, David F.


    The idea of reducing the Earth's greenhouse effect by sequestration of CO2 into the Earth's crust has been discussed and evaluated for more than two decades. Deep saline aquifers are the primary candidate formations for realization of this idea. Evaluation of reservoir capacity and the risk of CO2 leakage require a detailed modeling of the migration and distribution of CO2 in the subsurface structure. There is a finite risk that structural (or hydrodynamic) trapping by caprock may be compromised (e.g. by improperly abandoned wells, stratigraphic discontinuities, faults, etc.). Therefore, other trapping mechanisms (capillary trapping, dissolution, and mineralization) must be considered. Capillary trapping may be very important in providing a "secondary-seal", and is the focus of our investigation. The physical mechanism of CO2 trapping in porous media by capillary trapping incorporates three related processes, i.e. residual trapping, trapping due to hysteresis of the relative permeability, and trapping due to hysteresis of the capillary pressure. Additionally CO2 may be trapped in heterogeneous media due to difference in capillary pressure entry points for different materials. The amount of CO2 trapped by these processes is a complicated nonlinear function of the spatial distribution of permeability, permeability anisotropy, capillary pressure, relative permeability of brine and CO2, permeability hysteresis and residual gas saturation (as well as the rate, total amount and placement of injected CO2). Geological heterogeneities essentially affect the dynamics of a CO2 plume in subsurface environments. Recent studies have led to new conceptual and quantitative models for sedimentary architecture in fluvial deposits over a range of scales that are relevant to the performance of some deep saline reservoirs [1, 2]. We investigated how the dynamics of a CO2 plume, during and after injection, is influenced by the hierarchical and multi-scale stratal architecture in such

  10. Permeability of the small intestine after intra-arterial injection of histamine-type mediators and irradiation

    Permeability and selectivity of rabbit small intestine were estimated by a perfusion technique after intra-arterial injection of histamine-type mediators and an intestinal dose of 1.5 Mr gamma irradiation. It was shown that the histamine-type mediators caused an increase in capillary permeability which produced an overall moderate increase in transmucosal permeability with a moderate loss of selectivity. Local intestinal irradiation caused a very marked increase in permeability and a profound loss of selectivity. It was felt that this was produced partly by an increase in capillary permeability but largely by damage to the epithelial basement membrane. It is concluded that the intestinal capillary endothelium is both rate-limiting and selective, though not to a major degree in either case. The epithelial basement membrane, however, appears to be both rate-limiting and markedly selective. (author)

  11. Stress failure of pulmonary capillaries: role in lung and heart disease

    West, J. B.; Mathieu-Costello, O.


    Pulmonary capillaries have extremely thin walls to allow rapid exchange of respiratory gases across them. Recently it has been shown that the wall stresses become very large when the capillary pressure is raised, and in anaesthetised rabbits, ultrastructural damage to the walls is seen at pressures of 40 mm Hg and above. The changes include breaks in the capillary endothelial layer, alveolar epithelial layer, and sometimes all layers of the wall. The strength of the thin part of the capillary wall can be attributed to the type IV collagen in the extracellular matrix. Stress failure of pulmonary capillaries results in a high-permeability form of oedema, or even frank haemorrhage, and is apparently the mechanism of neurogenic pulmonary oedema and high-altitude pulmonary oedema. It also explains the exercise-induced pulmonary haemorrhage that occurs in all racehorses. Several features of mitral stenosis are consistent with stress failure. Overinflation of the lung also leads to stress failure, a common cause of increased capillary permeability in the intensive care environment. Stress failure also occurs if the type IV collagen of the capillary wall is weakened by autoantibodies as in Goodpasture's syndrome. Neutrophil elastase degrades type IV collagen and this may be the starting point of the breakdown of alveolar walls that is characteristic of emphysema. Stress failure of pulmonary capillaries is a hitherto overlooked and potentially important factor in lung and heart disease.

  12. How Capillary Rafts Sink

    Protiere, S; Aristoff, J; Stone, H


    We present a fluid dynamics video showing how capillary rafts sink. Small objects trapped at an interface are very common in Nature (insects walking on water, ant rafts, bubbles or pollen at the water-air interface, membranes...) and are found in many multiphase industrial processes. Thanks to Archimedes principle we can easily predict whether an object sinks or floats. But what happens when several small particles are placed at an interface between two fluids. In this case surface tension also plays an important role. These particles self-assemble by capillarity and thus form what we call a "capillary raft". We show how such capillary rafts sink for varying sizes of particles and define how this parameter affects the sinking process.

  13. Exploring the pressure resistance limits of monolithic silica capillary columns.

    Hara, Takeshi; Eeltink, Sebastiaan; Desmet, Gert


    We report on an experimental approach to measure the pressure stability and mechanical strength of monolithic silica capillary columns with different diameters (50 and 100μm i.d.) and considering two different domain sizes, typical for the second generation monoliths or smaller. The approach consists of exposing the capillaries to ultra-high pressures (gradually stepwise increased from 20 to 80MPa), with intermediate measurements of the column efficiency, permeability and retention factors to check the mechanical stability of the bed. It was observed that all tested columns withstood the imposed pressure stress, i.e., all the tested parameters remained unaffected up till the maximal test pressure of 80MPa. The applied pressure gradient corresponded to 320MPa/m. The two 100μm i.d.-capillary columns were also exposed to pressures between 80 and 90MPa for a prolonged time (8h), and this did not cause any damage either. PMID:27086284

  14. A capillary network model for coupled gas and water flow in engineered barriers

    A two-dimensional capillary network model for gas migration through a water-saturated medium is presented. The model is an extension of previously developed capillary bundle models, and provides a discrete alternative to classical continuum Darcy models. The need for such an alternative has become apparent from recent experimental results that suggest gas migrates through low permeability water-saturated media via a small number of preferential pathways

  15. Capillary electrophoresis - electrospray ionization mass spectrometry in small diameter capillaries

    Wahl, J.H.; Goodlett, D.R.; Udseth, H.R.; Smith, R.D.


    Methods (such as small inner diameter capillaries) are being explored to increase analyte sensitivity in capillary electrophoresis- electrospray ionization/mass spectroscopy(CE-ESI/MS). Results are reported for melittin in a protein mixture, with 10 to 100 {mu}m ID capillaries; and for a mixture of aprotinin, cytochrome c, myoglobin, and carbonic anhydrase, with 5 to 50 {mu}m ID capillaries. It is shown that an increase in solute sensitivity occurs when small ID capillaries ({lt} 20 {mu}m) are used in CE-ESI/MS for both a peptide and a protein mixture. 3 figs. (DLC)

  16. Changes in permeability caused by transient stresses: field observations, experiments, and mechanisms

    Manga, Michael; Beresnev, Igor; Brodsky, Emily E.; Elkhoury, Jean E.; Elsworth, Derek; Ingebritsen, Steve E.; Mays, David C.; Wang, Chi-yuen


    Oscillations in stress, such as those created by earthquakes, can increase permeability and fluid mobility in geologic media. In natural systems, strain amplitudes as small as 10–6 can increase discharge in streams and springs, change the water level in wells, and enhance production from petroleum reservoirs. Enhanced permeability typically recovers to prestimulated values over a period of months to years. Mechanisms that can change permeability at such small stresses include unblocking pores, either by breaking up permeability-limiting colloidal deposits or by mobilizing droplets and bubbles trapped in pores by capillary forces. The recovery time over which permeability returns to the prestimulated value is governed by the time to reblock pores, or for geochemical processes to seal pores. Monitoring permeability in geothermal systems where there is abundant seismicity, and the response of flow to local and regional earthquakes, would help test some of the proposed mechanisms and identify controls on permeability and its evolution.

  17. Permeability of Dentine

    Ghazali, Farid Bin Che


    This is an update on the present integrated knowledge regarding dentine permeability that assumed a role in dentine sensitivity and contribute clinically to the effective bonding properties of restorative dental materials. This paper will attempt to refer to in vivo and in vitro studies of dentine permeability and the various interrelated factors governing it.

  18. Permeable Pavements at Purdue

    Knapp, Jim


    Two case studies will be presented describing sustainable drainage alternatives. The processes used for the 2nd Street project in Seymour will provide a comparison of the design processes for conventional and green infrastructure solutions. Purdue University will discuss a number of permeable pavement installations on campus and provide a map for viewing. Asphalt, concrete, and permeable paver options will be discussed.

  19. Dynamic up-scaling of relative permeability in chalk

    Frykman, P.; Lindgaard, H.F.


    This paper describes how fine-scale geo-statistic reservoir models can be utilised for the up-scaling of two-phase flow properties, including both relative permeability and capillary pressure function. The procedure is applied to a North Sea chalk carbonate reservoir example, which is a high-porosity/low-permeability reservoir type. The study focuses on waterflooding as the main recovery scheme and for the given flow regime in the reservoir. The main purpose of the paper is to demonstrate the use of dynamic multi-step up-scaling methods in the preparation of detailed geological information for full field reservoir simulation studies. (au) EFP-96. 39 refs.

  20. Permeability prediction in chalks

    Alam, Mohammad Monzurul; Fabricius, Ida Lykke; Prasad, Manika


    The velocity of elastic waves is the primary datum available for acquiring information about subsurface characteristics such as lithology and porosity. Cheap and quick (spatial coverage, ease of measurement) information of permeability can be achieved, if sonic velocity is used for permeability...... prediction, so we have investigated the use of velocity data to predict permeability. The compressional velocity fromwireline logs and core plugs of the chalk reservoir in the South Arne field, North Sea, has been used for this study. We compared various methods of permeability prediction from velocities....... The relationships between permeability and porosity from core data were first examined using Kozeny’s equation. The data were analyzed for any correlations to the specific surface of the grain, Sg, and to the hydraulic property defined as the flow zone indicator (FZI). These two methods use two...

  1. Characterizing flow behavior for gas injection: Relative permeability of CO2-brine and N2-water in heterogeneous rocks

    Reynolds, C. A.; Krevor, S.


    We provide a comprehensive experimental study of steady state, drainage relative permeability curves with CO2-brine and N2-deionized water, on a single Bentheimer sandstone core with a simple two-layer heterogeneity. We demonstrate that, if measured in the viscous limit, relative permeability is invariant with changing reservoir conditions, and is consistent with the continuum-scale multiphase flow theory for water wet systems. Furthermore, we show that under capillary limited conditions, the CO2-brine system is very sensitive to heterogeneity in capillary pressure, and by performing core floods under capillary limited conditions, we produce effective relative permeability curves that are flow rate and fluid parameter dependent. We suggest that the major uncertainty in past observations of CO2-brine relative permeability curves is due to the interaction of CO2 flow with pore space heterogeneity under capillary limited conditions and is not due to the effects of changing reservoir conditions. We show that the appropriate conditions for measuring intrinsic or effective relative permeability curves can be selected simply by scaling the driving force for flow by a quantification of capillary heterogeneity. Measuring one or two effective curves on a core with capillary heterogeneity that is representative of the reservoir will be sufficient for reservoir simulation.

  2. Integrity of the alveolar-capillary barrier and alveolar surfactant system in smokers.

    Schmekel, B; Bos, J.A.; A. R. Khan; Wohlfart, B; Lachmann, B.; Wollmer, P.


    BACKGROUND: The permeability of the alveolar-capillary barrier to technetium-99m labelled diethylenetriamine pentaacetate (99mTc DTPA) is known to be greatly increased in smokers, but the underlying mechanism is poorly understood. Abnormal permeability of the alveolar epithelium as well as impaired surfactant function has been suggested. The purpose of this study was to examine transudation of urea and albumin into the alveoli and alveolar surfactant function in smokers and non-smokers and to...

  3. Effect of kaolin treatment temperature on mortar chloride permeability

    Puertas, F.; Mejía de Gutiérrez, R.; J. Torres


    The present paper discusses the results of chloride resistance tests conducted on ordinary Portland cement (OPC) mortars containing a Colombian kaolin pre-treated at temperatures of from 600 to 800 ºC. The resulting metakaolin (MK) was added to OPC mortar mixes in proportions of 10 and 20% by cement weight. The mortars were compared for physical and chemical properties, including capillary absorption, chloride permeability and pore microstructure as assessed by mercury porosimetry....

  4. Characterization and estimation of permeability correlation structure from performance data

    Ershaghi, I.; Al-Qahtani, M. [Univ. of Southern California, Los Angeles, CA (United States)


    In this study, the influence of permeability structure and correlation length on the system effective permeability and recovery factors of 2-D cross-sectional reservoir models, under waterflood, is investigated. Reservoirs with identical statistical representation of permeability attributes are shown to exhibit different system effective permeability and production characteristics which can be expressed by a mean and variance. The mean and variance are shown to be significantly influenced by the correlation length. Detailed quantification of the influence of horizontal and vertical correlation lengths for different permeability distributions is presented. The effect of capillary pressure, P{sub c1} on the production characteristics and saturation profiles at different correlation lengths is also investigated. It is observed that neglecting P{sub c} causes considerable error at large horizontal and short vertical correlation lengths. The effect of using constant as opposed to variable relative permeability attributes is also investigated at different correlation lengths. Next we studied the influence of correlation anisotropy in 2-D reservoir models. For a reservoir under five-spot waterflood pattern, it is shown that the ratios of breakthrough times and recovery factors of the wells in each direction of correlation are greatly influenced by the degree of anisotropy. In fully developed fields, performance data can aid in the recognition of reservoir anisotropy. Finally, a procedure for estimating the spatial correlation length from performance data is presented. Both the production performance data and the system`s effective permeability are required in estimating the correlation length.

  5. Comparative study of models for predicting permeability from nuclear magnetic resonance (NMR) logs in two Chinese tight sandstone reservoirs

    Xiao, Liang; Liu, Xiao-Peng; Zou, Chang-Chun; Hu, Xiao-Xin; Mao, Zhi-Qiang; Shi, Yu-Jiang; Guo, Hao-Peng; Li, Gao-Ren


    Based on the analysis of mercury injection capillary pressure (MICP) and nuclear magnetic resonance (NMR) experimental data for core plugs, which were drilled from two Chinese tight sandstone reservoirs, permeability prediction models, such as the classical SDR, Timur-Coates, the Swanson parameter, the Capillary Parachor, the R10 and R35 models, are calibrated to estimating permeabilities from field NMR logs, and the applicabilities of these permeability prediction models are compared. The processing results of several field examples show that the SDR model is unavailable in tight sandstone reservoirs. The Timur-Coates model is effective once the optimal T 2cutoff can be acquired to accurately calculate FFI and BVI from field NMR logs. The Swanson parameter model and the Capillary Parachor model are not always available in tight sandstone reservoirs. The R35 based model cannot effectively work in tight sandstone reservoirs, while the R10 based model is optimal in permeability prediction.

  6. Changes of microvascular architecture, ultrastructure and permeability of rat jejunal villi at different ages

    Yan-Min Chen; Jin-Sheng Zhang; Xiang-Lin Duan


    AIM: To investigate the changes of microvascular architecture, ultrastructure and permeability of rat jejunal villi at different ages.METHODS: Microvascular corrosion casting, scanning electron microscopy, transmission electron microscopy and Evans blue infiltration technique were used in this study.RESULTS: The intestinal villous plexus of adult rats consisted of arterioles, capillary network and venules. The marginal capillary extended to the base part of the villi and connected to the capillary networks of adjacent villi. In newborn rats,the villous plexus was rather simple, and capillary network was not formed. The villous plexus became cone-shaped and was closely arrayed in ablactation rats. In adult rats,the villous plexus became tongue-shaped and was enlarged both in height and width. In aged rats, the villous plexus shrank in volume and became shorter and narrower. The diametral ratio of villous arteriole to villous venule increased as animals became older. The number of endothelial holes,the thickness of basal membrane and the permeability of microvasculature were increased over the entire course of development from newborn period to aged period.CONCLUSION: The digestive and absorptive functions of the rat jejunum at different ages are highly dependent upon the state of villous microvascular architecture and permeability, and blood circulation is enhanced by collateral branches such as marginal capillary, through which blood is drained to the capillary networks of adjacent villi.

  7. Barrier Functionality of Porcine and Bovine Brain Capillary Endothelial Cells

    Ailar Nakhlband


    Full Text Available Introduction: To date, isolated cell based blood-brain barrier (BBB models have been widely used for brain drug delivery and targeting, due to their relatively proper bioelectrical and permeability properties. However, primary cultures of brain capillary endothelial cells (BCECs isolated from different species vary in terms of bioelectrical and permeability properties. Methods: To pursue this, in the current investigation, primary porcine and bovine BCECs (PBCECs and BBCECs, respectively were isolated and used as an in vitro BBB model. The bioelectrical and permeability properties were assessed in BCECs co-cultured with C6 cells with/without hydrocortisone (550 nM. The bioelectrical properties were further validated by means of the permeability coefficients of transcellular and paracellular markers. Results: The primary PBCECs displayed significantly higher trans-endothelial electrical resistance (~900 W.cm2 than BBCECs (~700 W.cm2 - both co-cultured with C6 cells in presence of hydrocortisone. Permeability coefficients of propranolol/diazepam and mannitol/sucrose in PBCECs were ~21 and ~2 (×10-6 cm.sec-1, where these values for BBCECs were ~25 and ~5 (×10-6 cm.sec-1. Conclusion: Upon our bioelectrical and permeability findings, both models display discriminative barrier functionality but porcine BCECs seem to provide a better platform than bovine BCECs for drug screening and brain targeting.

  8. Factors influencing unsteady relative permeability of a mixed-wet reservoir rock

    Capillarity, viscous fingering, and heterogeneity influence the flow in a core plug and hence affect the relative permeability determined from an unsteady test. Several unsteady water/oil relative permeability tests were carried out in a mixed-wet core while in-situ 3D saturation distribution was monitored by a computerized-tomography (CT) scanner. Results illustrate included in this paper that, in the early part of the Johnson-Bossler-Naumann (JBN) method, relative permeability is dominated by fingering and heterogeneity effects. The later part of this method (>1 PV), however, represents the relative permeability of the end-face saturation and is influenced by the capillary number and throughput. Thus, laboratory results must be scaled to the field on the basis of the flow parameters: end-effect, capillary, instability, and heterogeneity numbers

  9. Comparative study of four immortalized human brain capillary endothelial cell lines, hCMEC/D3, hBMEC, TY10, and BB19, and optimization of culture conditions, for an in vitro blood–brain barrier model for drug permeability studies

    Eigenmann, Daniela E; Xue, Gongda; Kwang S Kim; Moses, Ashlee V.; Hamburger, Matthias; Oufir, Mouhssin


    Background Reliable human in vitro blood–brain barrier (BBB) models suitable for high-throughput screening are urgently needed in early drug discovery and development for assessing the ability of promising bioactive compounds to overcome the BBB. To establish an improved human in vitro BBB model, we compared four currently available and well characterized immortalized human brain capillary endothelial cell lines, hCMEC/D3, hBMEC, TY10, and BB19, with respect to barrier tightness and paracellu...

  10. Seismic waves increase permeability.

    Elkhoury, Jean E; Brodsky, Emily E; Agnew, Duncan C


    Earthquakes have been observed to affect hydrological systems in a variety of ways--water well levels can change dramatically, streams can become fuller and spring discharges can increase at the time of earthquakes. Distant earthquakes may even increase the permeability in faults. Most of these hydrological observations can be explained by some form of permeability increase. Here we use the response of water well levels to solid Earth tides to measure permeability over a 20-year period. At the time of each of seven earthquakes in Southern California, we observe transient changes of up to 24 degrees in the phase of the water level response to the dilatational volumetric strain of the semidiurnal tidal components of wells at the Piñon Flat Observatory in Southern California. After the earthquakes, the phase gradually returns to the background value at a rate of less than 0.1 degrees per day. We use a model of axisymmetric flow driven by an imposed head oscillation through a single, laterally extensive, confined, homogeneous and isotropic aquifer to relate the phase response to aquifer properties. We interpret the changes in phase response as due to changes in permeability. At the time of the earthquakes, the permeability at the site increases by a factor as high as three. The permeability increase depends roughly linearly on the amplitude of seismic-wave peak ground velocity in the range of 0.21-2.1 cm s(-1). Such permeability increases are of interest to hydrologists and oil reservoir engineers as they affect fluid flow and might determine long-term evolution of hydrological and oil-bearing systems. They may also be interesting to seismologists, as the resulting pore pressure changes can affect earthquakes by changing normal stresses on faults. PMID:16810253

  11. Tapered capillary optics

    Hirsch, Gregory


    A metal or glass wire is etched with great precision into a very narrowly tapering cone which has the shape of the desired final capillary-optics bore. By controlling the rate of removal of the wire from an etchant bath, a carefully controlled taper is produced. A sensor measures the diameter of the wire as it leaves the surface of the etchant. This signal is used for feedback control of the withdrawal speed. The etched wire undergoes a treatment to produce an extremely low surface-roughness. The etched and smoothed wire is coated with the material of choice for optimizing the reflectivity of the radiation being focused. This could be a vacuum evaporation, sputtering, CVD or aqueous chemical process. The coated wire is either electroplated, built up with electroless plating, or encapsulated in a polymer cylinder such as epoxy to increase the diameter of the wire for easier handling and greater robustness. During this process, the wire is vertically oriented and tensioned to assure that the wire is absolutely straight. The coated and electroformed wire is bonded to a flat, rigid substrate and is then periodically segmented by cutting or etching a series of narrow slits or grooves into the wire. The wire is vertically oriented and tensioned during the bonding process to assure that it is straight. The original wire material is then chemically etched away through the slits or otherwise withdrawn to leave the hollow internal bore of the final tapered-capillary optical element.

  12. Biomedical applications of capillary electrophoresis

    Kartsova, L. A.; Bessonova, E. A.


    The review deals with modern analytical approaches used in capillary electrophoresis for solving medical and biological problems: search for biomarkers of various diseases and rapid diagnosis based on characteristic profiles of biologically active compounds by capillary electrophoresis with mass spectrometric detection; monitoring of the residual drugs in biological fluids for evaluating the efficiency of drug therapy; testing of the enantiomeric purity of pharmaceutical products; the use of novel materials as components of stationary and pseudo-stationary phases in capillary electrophoresis and capillary electrochromatography to increase the selectivity of separation of components of complex matrices; and identification of various on-line preconcentration techniques to reduce the detection limits of biologically active analytes. A topical trend in capillary electrophoresis required in clinical practice, viz., the design of microfluidic systems, is discussed. The bibliography includes 173 references.

  13. Capillary optics for radiation focusing

    Capillary lens technology may ultimately bring benefits to neutron and x-ray-based science like conventional lenses with visible light. Although the technology is not yet 10 years old, these lenses have already had a significant impact in engineering, science, and medicine. Capillary lenses are advantageous when it is desirable to increase the radiation flux at a location without regard to its angular divergence. PNNL has worked to improve the technology in several ways. A single, optimally tapered capillary was manufactured, which allows intensity gains of a factor of 270 for an initially parallel, incident x-ray beam. Feasibility of constructing neutron lenses using 58Ni (particularly effective at reflecting neutrons) has been explored. Three applications for capillary optics have been identified and studied: neutron telescope, Gandolphi x-ray diffractometry, and neutron radiotherapy. A brief guide is given for determining which potential applications are likely to be helped by capillary optics

  14. Effect of carbon dioxide on the permeability of synthetic Hanford salt cake

    In well-drained salt cakes where no capillary-held mother liquor was present, the reaction between NaOH and CO2(g) produced enough solids to lower the permeability by a factor of 20. This same reaction lowered the permeability by at least three orders of magnitude when the salt cake was saturated with mother liquor. Thus, while the reaction between CO2 and NaOH can dry the liquids in Hanford salt cake, the permeability is decreased to such an extent that use of this method becomes impracticable

  15. Measurements of the capillary trapping of super-critical carbon dioxide in Berea sandstone

    Pentland, Christopher H.; El-Maghraby, Rehab; Iglauer, Stefan; Blunt, Martin J.


    We measure primary drainage capillary pressure and the relationship between initial and residual non-wetting phase saturation for a supercritical carbon dioxide (CO2)-brine system in Berea sandstone. We use the semi-permeable disk (porous-plate) coreflood method. Brine and CO2 were equilibrated prior to injection to ensure immiscible displacement. A maximum CO2 saturation of 85% was measured for an applied capillary pressure of 296 kPa. After injection of brine the CO2 saturation dropped to 35%; this is less than the maximum trapped saturation of 48% measured in an equivalent n-decane (oil)-brine experiment. The dimensionless capillary pressure is the same to within experimental error for supercritical CO2-brine, n-decane-brine and a mercury-air system. CO2 is the non-wetting phase and significant quantities can be trapped by capillary forces. We discuss the implications for CO2 storage.

  16. Modeling of the permeability of a sandstone reservoir of the North Sea using a combination of image processing data and capillary pressure curves; Modelisation de la permeabilite d'un reservoir greseux de Mer du Nord par combinaison de donnees d'analyse d'images et de courbes de pression capillaire

    Belin, S.; Fritz, B. [Centre de Geochimie de la Surface, UMR 7517, 67 - Strasbourg (France); Anguy, Y.; Bernard, D. [Lab. Energetique et Phenomenes de transfert, UMR 8508, 33 - Talence (France)


    This study deals with the relation between the micro-geometry and the permeability in a series of samples from a sandstone reservoir of the Alwyn area (North Sea). The samples have various petro-physical properties with porosities comprised between 13 and 26% and permeabilities ranging from 0.1 to 3000 mD. Five different types of pores were identified using micro-graphic images of the porosity. The spatial organization of pores and the 3-D connectivity between adjacent pores is deduced from the image processing data and the petrophysical data combined using multi-linear regression models. This approach has permitted to demonstrate a relation between the type of pores and size of the access radius. (J.S.)

  17. A capillary network model for gas migration in engineered barriers

    Gas may be generated in a waste repository by a number of mechanisms, including anaerobic corrosion of metals and microbial degradation. Scoping calculations indicate that a free gas phase will probably form. Here attention is focused on two hazards this may pose. First, a gas pressure buildup may damage engineered barriers. Second, migrating gas may displace contaminated pore water. In previous studies, Darcy two-phase flow models have been used to calculate gas pressures and pore water displacement. A two-dimensional capillary network model has been developed and implemented in a numerical code, GARNET. Example calculations of the migration of gas from a point source have been undertaken to demonstrate its functionality and to indicate how phenomena, such as intermittent gas fluxes, may be modelled. Results indicate that the capillary network model reproduces behaviour observed in gas migration through low permeability media, and is a viable alternative to Darcy two-phase flow models

  18. Advances in capillary electrophoresis

    In the 1980s, capillary electrophoresis (CE) developed rapidly into a first-class analytical separation technique. Its advances in instru-mentation and method development will not only enhance or complement existing mature separation techniques such as liquid chromatography and conventional slab gel electrophoresis, but will also severely challenge these separation methods. A brief overview of most striking achievement of CE in the 1980s is given, which illustrates the challenge to liquid chromatography and conventional slab gel electrophoresis, and some detailed discussions are presented to highlight the advantages of CE. New developments in CE that can be expected for the 1990s include especially column technology, separation chemistry and instrumentation, which will serve further to diversify and improve the applicability of this technique in areas which are poorly addressed by other separation methods. This paper considers and speculates on the technological advancements that can be expected to emerge for CE in the 1990s. (author). 95 refs.; 14 figs

  19. Permeability heterogeneity in cross-bedded sandstones: Impact on water/oil displacement in fluvial reservoirs. Doctoral thesis

    Hartkamp-Bakker, C.A.


    This study focuses on quantitatively defining the permeability/capillary-pressure characteristics in a number of well-exposed analoges and cored reservoirs by minipermeametry. Average contrasts in permeability are determined for fluvial cross-bedding and combined with thin-section studies to characterize the grain size, sorting and compositional characteristics that determine permeability contrasts. In addition capillary pressure experiments of laminated samples were carried out to study the contrasting capillary-pressure characteristics between the laminae. Water/oil displacement through cross-bedding by numerical and physical modelling were performed in close corporation with reservoir engineers to increase the understanding of the geological and physical conditions under which movable-oil entrapment occurs. Finally, the likely percentages of movable oil that are initially trapped in a cross-bedded reservoir are estimated.

  20. Liquid CO2 displacement of water in a dual-permeability pore network micromodel.

    Zhang, Changyong; Oostrom, Mart; Grate, Jay W; Wietsma, Thomas W; Warner, Marvin G


    Permeability contrasts exist in multilayer geological formations under consideration for carbon sequestration. To improve our understanding of heterogeneous pore-scale displacements, liquid CO(2) (LCO(2))-water displacement was evaluated in a pore network micromodel with two distinct permeability zones. Due to the low viscosity ratio (logM = -1.1), unstable displacement occurred at all injection rates over 2 orders of magnitude. LCO(2) displaced water only in the high permeability zone at low injection rates with the mechanism shifting from capillary fingering to viscous fingering with increasing flow rate. At high injection rates, LCO(2) displaced water in the low permeability zone with capillary fingering as the dominant mechanism. LCO(2) saturation (S(LCO2)) as a function of injection rate was quantified using fluorescent microscopy. In all experiments, more than 50% of LCO(2) resided in the active flowpaths, and this fraction increased as displacement transitioned from capillary to viscous fingering. A continuum-scale two-phase flow model with independently determined fluid and hydraulic parameters was used to predict S(LCO2) in the dual-permeability field. Agreement with the micromodel experiments was obtained for low injection rates. However, the numerical model does not account for the unstable viscous fingering processes observed experimentally at higher rates and hence overestimated S(LCO2). PMID:21774502

  1. Permeability mapping in porous media by magnetization prepared centric-scan SPRITE

    Romanenko, Konstantin V.; Balcom, Bruce J.


    The ability of porous media to transmit fluids is commonly referred to as permeability. The concept of permeability is central for hydrocarbon recovery from petroleum reservoirs and for studies of groundwater flow in aquifers. Spatially resolved measurements of permeability are of great significance for fluid dynamics studies. A convenient concept of local Darcy's law is suggested for parallel flow systems. The product of porosity and mean velocity images in the plane across the average flow direction is directly proportional to permeability. Single Point Ramped Imaging with T 1 Enhancement (SPRITE) permits reliable quantification of local fluid content and flow in porous media. It is particularly advantageous for reservoir rocks characterized by fast magnetic relaxation of a saturating fluid. Velocity encoding using the Cotts pulsed field gradient scheme improves the accuracy of measured flow parameters. The method is illustrated through measurements of 2D permeability maps in a capillary bundle, glass bead packs and composite sandstone samples.

  2. Analysis of Capillary Rise in Asymmetric Branch-Like Capillary

    Li, Caoxiong; Shen, Yinghao; Ge, Hongkui; Yang, Zhihui; Su, Shuai; Ren, Kai; Huang, Heyu


    Transport in porous media is common in nature, attracting many attentions for a long time. Tree-like network model is often used as a simplification for porous space, expressing the complexity of pore spaces instead of capillary bundle. To investigate spontaneous imbibition characteristics in this network, a dynamic asymmetric branch-like capillary model is used to represent basic network structure, using fractal method to represent tortuosity. This work investigates the influence of parameters on imbibition process in the branch-like capillary model. An analytical equation for the imbibition mass versus time is derived. Parameters from capillary structures to liquid properties are taken into account and analyzed based on the numerical solution of the equation. It is found that the imbibition process in asymmetric branch-like capillary model can be recognized by four sections and brunching tubes are positive for imbibition process. Concomitantly, meniscus arrest event is simulated and discussed. Moreover, the influence of parameters on imbibition process is discussed. These parameters can be classified as static and dynamic. Static parameters mainly change the capillary force, which are related to the ultimate imbibition mass or imbibition ability, while dynamic parameters mainly have influence on resistance of flowing fluid, which are related to the imbibition speed in the imbibition process.

  3. Permeability measuremens of brazilian Eucalyptus

    Marcio Rogério da Silva; Gilmara de Oliveira Machado; Jay Deiner; Carlito Calil Junior


    The permeability of Brazilian Eucalyptus grandis and Eucalyptus citriodora wood was measured in a custom build gas analysis chamber in order to determine which species could be successfully treated with preservatives. Liquid permeability was tested using an emulsion of Neen oil and a control of distillated water. Air was used to test the gas phase permeability. For both Eucalyptus grandis and Eucalyptus citriodora, the longitudinal permeability of gas was shown to be about twice as great as t...

  4. Surface Tension and Capillary Rise

    Walton, Alan J.


    Discussion of the shortcomings of textbook explanations of surface tension, distinguishing between concepts of tension and capillary rise. The arguments require only a clear understanding of Newtonian mechanics, notably potential energy. (DF)

  5. Capillary Condensation in Confined Media

    Charlaix, Elisabeth


    We review here the physics of capillary condensation of liquids in confined media, with a special regard to the application in nanotechnologies. The thermodynamics of capillary condensation and thin film adsorption are first exposed along with all the relevant notions. The focus is then shifted to the modelling of capillary forces, to their measurements techniques (including SFA, AFM and crack tips) and to their influence on AFM imaging techniques as well as on the static and dynamic friction properties of solids (including granular heaps and sliding nanocontacts). A great attention is spent in investigating the delicate role of the surface roughness and all the difficulties involved in the reduction of the probe size to nanometric dimensions. Another major consequence of capillary condensation in nanosystems is the activation of several chemical and corrosive processes that can significantly alter the surface properties, such as dissolution/redeposition of solid materials and stress-corrosion crack propagati...

  6. Capillary electrophoresis electrospray ionization mass spectrometry interface

    Smith, Richard D.; Severs, Joanne C.


    The present invention is an interface between a capillary electrophoresis separation capillary end and an electrospray ionization mass spectrometry emitter capillary end, for transporting an anolyte sample from a capillary electrophoresis separation capillary to a electrospray ionization mass spectrometry emitter capillary. The interface of the present invention has: (a) a charge transfer fitting enclosing both of the capillary electrophoresis capillary end and the electrospray ionization mass spectrometry emitter capillary end; (b) a reservoir containing an electrolyte surrounding the charge transfer fitting; and (c) an electrode immersed into the electrolyte, the electrode closing a capillary electrophoresis circuit and providing charge transfer across the charge transfer fitting while avoiding substantial bulk fluid transfer across the charge transfer fitting. Advantages of the present invention have been demonstrated as effective in providing high sensitivity and efficient analyses.

  7. Biodiesel permeability in polyethylene

    RICHAUD, Emmanuel; FLACONNÈCHE, Bruno; Verdu, Jacques


    This paper reports solubility and diffusivity data for soy and rapeseed methyl esters in polyethylene together with comparisons with methyl oleate and linoleate. These data showed that there is no significant difference in diffusivity and solubility between all these penetrants. Data were used to discuss the reliability of predictive models for diffusion and solubility of additive type molecules into semi-crystalline thermoplastic polymers. Permeability data were monitored by a new device, th...

  8. Stainless Steel Permeability

    Buchenauer, Dean A. [Sandia National Laboratories (SNL-CA), Livermore, CA (United States); Karnesky, Richard A. [Sandia National Laboratories (SNL-CA), Livermore, CA (United States)


    An understanding of the behavior of hydrogen isotopes in materials is critical to predicting tritium transport in structural metals (at high pressure), estimating tritium losses during production (fission environment), and predicting in-vessel inventory for future fusion devices (plasma driven permeation). Current models often assume equilibrium diffusivity and solubility for a class of materials (e.g. stainless steels or aluminum alloys), neglecting trapping effects or, at best, considering a single population of trapping sites. Permeation and trapping studies of the particular castings and forgings enable greater confidence and reduced margins in the models. For FY15, we have continued our investigation of the role of ferrite in permeation for steels of interest to GTS, through measurements of the duplex steel 2507. We also initiated an investigation of the permeability in work hardened materials, to follow up on earlier observations of unusual permeability in a particular region of 304L forgings. Samples were prepared and characterized for ferrite content and coated with palladium to prevent oxidation. Issues with the poor reproducibility of measurements at low permeability were overcome, although the techniques in use are tedious. Funding through TPBAR and GTS were secured for a research grade quadrupole mass spectrometer (QMS) and replacement turbo pumps, which should improve the fidelity and throughput of measurements in FY16.

  9. Determination Permeability Coefficient from Piezocone

    Qiang Wang


    Full Text Available The permeability coefficient of soil profile is one of the problems concerned by engineers, and the determination of permeability coefficient method mainly relies on the laboratory permeability test and field pumping test, but these tests are time-consuming and inefficient, and especially the permeability coefficient of soil under the condition of partial drainage was difficult to determine; in this paper, the modern digital CPTU technology was used. Dimensional permeability KT was defined by using the dimensionless normalized cone tip resistance Qt, friction factor Fr, and pore pressure ratio Bq, these parameters enable plots of Bq-Qt, Fr-Qt, Bq-Fr to be contoured KT and hence for permeability coefficient. The relationship has been applied to Nanjing 4th Yangtze river bridge, and compared with laboratory penetration test. The results indicate that the method can accurately determine the permeability coefficient of soil under partial drainage condition and provide the theoretical basis for engineering application.

  10. Relative permeability and the microscopic distribution of wetting and nonwetting phases in the pore space of Berea sandstone

    Schlueter, E.M.; Cook, N.G.W. [Lawrence Berkeley Lab., CA (United States)]|[California Univ., Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering; Witherspoon, P.A.; Myer, L.R. [Lawrence Berkeley Lab., CA (United States)


    Experiments to study relative permeabilities of a partially saturated rock have been carried out in Berea sandstone using fluids that can be solidified in place. The effective permeability of the spaces not occupied by the wetting fluid (paraffin wax) or the nonwetting fluid (Wood`s metal), have been measured at various saturations after solidifying each of the phases. The tests were conducted on Berea sandstone samples that had an absolute permeability of about 600 md. The shape of the laboratory-derived relative permeability vs. saturation curves measured with the other phase solidified conforms well with typical curves obtained using conventional experimental methods. The corresponding wetting and nonwetting fluid distributions at different saturations are presented and analyzed in light of the role of the pore structure in the invasion process, and their impact on relative permeability and capillary pressure. Irreducible wetting and nonwetting phase fluid distributions are studied. The effect of clay minerals on permeability is also assessed.

  11. A 3D lattice Boltzmann effective media study: understanding the role of C-S-H and water saturation on the permeability of cement paste

    A 3D lattice Boltzmann model is developed and used to calculate the water and gas permeabilities of model cement pastes at different degrees of water saturation. In addition to permeable micron-sized capillary pores and impermeable solid inclusions, the lattice Boltzmann model comprises weakly-permeable nano-porous calcium silicate hydrate (C-S-H). The multi-scale problem is addressed by using an effective media approach based on the idea of partial bounce-back. The model cement paste microstructures are generated with the platform µic. The critical parameters, C-S-H density and capillary porosity, are taken from 1H nuclear magnetic resonance relaxation analysis. The distribution of water and air is defined according to the Kelvin–Laplace law. It is found that when the capillary porosity is completely saturated with a fluid (either water or gas), the calculated intrinsic permeability is in good agreement with measurements of gas permeability on dried samples (10−17–10−16 m2). However, as the water saturation is reduced, the calculated apparent water permeability decreases and spans the full range of experimentally measured values (10−16–10−22 m2). It is concluded that the degree of capillary water saturation is the major cause for variation in experimental permeability measurements. It is further concluded that the role of the weakly-permeable C-S-H, omitted in earlier modelling studies, is critical for determining the permeability at low capillary saturation. (paper)

  12. Relative permeability through fractures

    Diomampo, Gracel, P.


    The mechanism of two-phase flow through fractures is of importance in understanding many geologic processes. Currently, two-phase flow through fractures is still poorly understood. In this study, nitrogen-water experiments were done on both smooth and rough parallel plates to determine the governing flow mechanism for fractures and the appropriate methodology for data analysis. The experiments were done using a glass plate to allow visualization of flow. Digital video recording allowed instantaneous measurement of pressure, flow rate and saturation. Saturation was computed using image analysis techniques. The experiments showed that gas and liquid phases flow through fractures in nonuniform separate channels. The localized channels change with time as each phase path undergoes continues breaking and reforming due to invasion of the other phase. The stability of the phase paths is dependent on liquid and gas flow rate ratio. This mechanism holds true for over a range of saturation for both smooth and rough fractures. In imbibition for rough-walled fractures, another mechanism similar to wave-like flow in pipes was also observed. The data from the experiments were analyzed using Darcy's law and using the concept of friction factor and equivalent Reynold's number for two-phase flow. For both smooth- and rough-walled fractures a clear relationship between relative permeability and saturation was seen. The calculated relative permeability curves follow Corey-type behavior and can be modeled using Honarpour expressions. The sum of the relative permeabilities is not equal one, indicating phase interference. The equivalent homogeneous single-phase approach did not give satisfactory representation of flow through fractures. The graphs of experimentally derived friction factor with the modified Reynolds number do not reveal a distinctive linear relationship.

  13. Permeability measuremens of brazilian Eucalyptus

    Marcio Rogério da Silva


    Full Text Available The permeability of Brazilian Eucalyptus grandis and Eucalyptus citriodora wood was measured in a custom build gas analysis chamber in order to determine which species could be successfully treated with preservatives. Liquid permeability was tested using an emulsion of Neen oil and a control of distillated water. Air was used to test the gas phase permeability. For both Eucalyptus grandis and Eucalyptus citriodora, the longitudinal permeability of gas was shown to be about twice as great as the liquid phase permeability. No radial permeability was observed for either wood. The permeability of air and water through the sapwood of Eucalyptus grandis was greater than that through the sapwood of Eucalyptus citriodora. The permeability of neen oil preservative through the sapwood of Eucalyptus grandis was also greater than through the sapwood of E. Citradora, but the difference was not statistically significant. Scanning Electron Microscopy images showed that the distribution and obstruction in the vessels could be correlated with observed permeability properties. Irrespective of the causes of differences in permeability between the species, the fluid phase flux through the sapwood of both species was significant, indicating that both Eucalyptus grandis and Eucalyptus citriodora could be successfully treated with wood preservative.

  14. Laser-based capillary polarimeter.

    Swinney, K; Hankins, J; Bornhop, D J


    A laser-based capillary polarimeter has been configured to allow for the detection of optically active molecules in capillary tubes with a characteristic inner diameter of 250 microm and a 39-nL (10(-9)) sample volume. The simple optical configuration consists of a HeNe laser, polarizing optic, fused-silica capillary, and charge-coupled device (CCD) camera in communication with a laser beam analyzer. The capillary scale polarimeter is based on the interaction between a polarized laser beam and a capillary tube, which results in a 360 degree fan of scattered light. This array of scattered light contains a set of interference fringe, which respond in a reproducible manner to changes in solute optical activity. The polarimetric utility of the instrument will be demonstrated by the analysis of two optically active solutes, R-mandelic acid and D-glucose, in addition to the nonoptically active control, glycerol. The polarimetric response of the system is quantifiable with detection limits facilitating 1.7 x 10(-3) M or 68 x 10(-12) nmol (7 psi 10(-9) g) sensitivity. PMID:11315158


    based mixes leads to high total and capillary porosities. These two conditions generally lead to higher permeabilities as has been well documented in the literature for typical cementitious pastes in water. Therefore, it is not unexpected that the hydraulic conductivities of these Saltstone mixes are relatively high

  16. Reservoir characteristics of low-permeability sandstones in the Rocky Mountains

    Byrnes, A.P.


    Understanding gas production from low-permeability sandstones requires an understanding of the in situ porosity, brine saturation, and effective gas permeability at reservoir brine saturation. Diagenesis in these sandstones commonly resulted in the destruction of much of the original intergranular porosity and left dissolved grains, clay-filled pores, and sheet-like connecting intergranular pore throats. Pore throats or channels that connect larger pores typically range in size from 1 to 0.1 micron and represent only a small portion of the total porosity. In most low-permeability sandstones, porosity is not significantly changed by confining stress changes, but in situ effective gas permeabilities range from 10 to 1,000 times less than routine air permeability. The influence of confining stress on permeability can be attributed primarily to the decrease in size of the thin, tabular pore throats that connect the larger pores. Under stress, pore throats decrease in diameter by up to 50% to 70% resulting in permeability decreases of 10 to 40 times. Gas effective permeabilities also decrease rapidly to less than 1% of absolute values at water saturations above approximately 40% to 50%. {open_quotes}Irreducible{close_quotes} water saturations increase with decreasing porosity and permeability, and, in sandstones with less than 0.01 md permeability, {open_quotes}irreducible{close_quotes} water saturations increase dramatically. Cumulative flow and storage capacity plots indicate that very thin higher permeability intervals typically yield a large percentage of the cumulative flow capacity. Increased water saturations due to drilling or stimulation result in lower effective gas permeabilities and can unknowingly be stabilized by capillary pressure forces if pore pressures are decreased. This type of formation damage can be remedied by increasing the gas pore pressure to displace mobile water.

  17. Non-Aqueous Capillary Electrophoresis

    Szumski, Michał; Buszewski, Bogusław

    Non-aqueous capillary electrophoresis and capillary electrochromatography are special variants of these techniques. Here, organic solvents or their mixtures with or without dissolved electrolytes are used as separation buffer or mobile phase, respectively. The most important features of non-aqueous systems are: better solubility of more hydrophobic ionic substances (many natural products) than in water, much less current and Joule heating allows for using highly concentrated buffers and/or larger capillary internal diameters, polar interactions are enhanced in organic solvents which is often highly advantageous in chiral separation systems. This chapter presents most frequently used solvents, their properties, as well as shows pH* scale which is often used in non-aqueous systems.

  18. a Fractal Permeability Model for Shale Matrix with Multi-Scale Porous Structure

    Sheng, Mao; Li, Gensheng; Tian, Shouceng; Huang, Zhongwei; Chen, Liqiang


    Nanopore structure and its multiscale feature significantly affect the shale-gas permeability. This paper employs fractal theory to build a shale-gas permeability model, particularly considering the effects of multiscale flow within a multiscale pore space. Contrary to previous studies which assume a bundle of capillary tubes with equal size, in this research, this model reflects various flow regimes that occur in multiscale pores and takes the measured pore-size distribution into account. The flow regime within different scales is individually determined by the Knudsen number. The gas permeability is an integral value of individual permeabilities contributed from pores of different scales. Through comparing the results of five shale samples, it is confirmed that the gas permeability varies with the pore-size distribution of the samples, even though their intrinsic permeabilities are the same. Due to consideration of multiscale flow, the change of gas permeability with pore pressure becomes more complex. Consequently, it is necessary to cover the effects of multiscale flow while determining shale-gas permeability.

  19. Vertical permeability from in situ horizontal measurements in shaly sand reservoirs

    Zahaf, K. [SONATRACH CRD, Boumerdes (Algeria); Tiab, D. [Oklahoma Univ., Norman, OK (United States)


    Complex variations of reservoir continuity, like porosity, permeability, and capillary pressure are exhibited by reservoirs, and the oil industry is becoming increasingly aware of this situation. They are a reflection of the depositional process and the diagenetic and tectonic changes that took place afterwards. The inadequacy of simple models is often apparent to accurately predict reservoir performance and for the design of a field production management plan optimizing recovery. The quality of the reservoir under water injection where the recovery factor is very sensitive to reservoir heterogeneity has a great influence on the optimization of recovery. Vertical and lateral permeability distribution must be accurately understood. The determination of vertical permeability from in-situ horizontal permeability in shaly reservoirs was the main focus of a research project, whose results are presented in this paper. The type of shale (Kaolinite, Chlorite, and Illite) and grain size were examined. Various water saturation correlations for Shaly-Sand formation were used to derive the in-situ vertical permeability correlations. A number of vertical permeability relationships were established as function of horizontal permeability, hydraulic mean radius grain size, and the amount and/or type of shale. The calculation of real oil field vertical and horizontal permeabilities was effected using the generalized models developed. The Trias Argileux Greseux inferior (TAGI) was selected for the field study and is located in Algeria.16 refs., 8 figs.

  20. Low Permeability Polyimide Insulation Project

    National Aeronautics and Space Administration — Resodyn Technologies proposes a new technology that enables the application of polyimide based cryogenic insulation with low hydrogen permeability. This effort...

  1. Spectroscopic Approach to Capillary-Alveolar Membrane Damage Induced Acute Lung Injury

    Jing Wang


    Full Text Available BACKGROUND: Acute (or adult respiratory distress syndrome (ARDS is often associated with a high mortality rate in the critical care population. The term acute lung injury (ALI, a primitive phase of ARDS, was introduced by the European and American consensus groups to provide early diagnoses of ARDS. The pathophysiological characterization of ALI/ARDS – an increased pulmonary capillary-alveolar membrane barrier permeability – is generally not included in current intensive care unit diagnosis criteria.

  2. Effect and mechanism of stresses on rock permeability at different scales

    YIN Shangxian; WANG Shangxu


    The effect of geo-stress fields on macroscopic hydro-geological conditions or microcosmic permeability of water-bearing media should follow some laws or principles. Cases study and tests show that: (1) At macro-geologic large scale, deformed and crashed rocks which were induced by geo-stress fields changing provided space for groundwater storage and flow. Groundwater adjusts water-bearing space and dilatants fractures by flowing and press transferring. Coupling of liquid and solid can be implemented for rocks and groundwater. Although tectonic fields witness several times of change and build-up in geological time, stress fields forming regional tectonic framework are coherent with seepage fields, orientation of the maximum horizontal stress demonstrates main seepage directions. (2) At macro-geologic middle scale, zones of stresses changing sharply, quite low stresses,stress or shear concentration can be used to show locations and types of main fractures, zones of geo-stresses changing equably can be acted as normal base media zones of tri-porosity media. (3) At micro-geologic small scale, tri-porosity media include fractured rocks, porous rocks and capillary rocks. Investigations indicate that porosity or permeability is functions of effective stresses, and porosity or permeability changing rules of porous rocks with variation of effective stresses can be described as the index model, the model of power exponent functions is suitable for those of fractured rocks, the model of the second power parabola for capillary rocks. The porosity and permeability loss in fractured rocks, which are greater than that in porous rocks, are shown by calculation of effective compressive coefficient and closing pressure in cracks. The calculations can also explain themechanism why porosity changes are always larger than permeability changes. It is proved by the thick wall cylinder theory that the second power parabola relation between porosity or permeability loss and effective

  3. Capillary thinning of polymeric filaments

    Kolte, Mette Irene; Szabo, Peter


    The capillary thinning of filaments of a Newtonian polybutene fluid and a viscoelastic polyisobutylene solution are analyzed experimentally and by means of numerical simulation. The experimental procedure is as follows. Initially, a liquid sample is placed between two cylindrical plates. Then, th...

  4. Capillary thinning of polymeric filaments

    Kolte, Mette Irene; Szabo, Peter; Hassager, Ole

    The capillary thinning of a polymeric filament is analysed experimentally as well as by means of numerical simulation. The experimental procedure is as follows. Initially a liquid sample is kept between two cylindrical plates. Then the bottom plate is lowered under gravity to yield a given strain...

  5. Ion guiding in alumina capillaries

    Juhász, Z.; Sulik, B.; Biri, S.;


    Transmission of a few keV impact energy Ne ions through capillaries in anodic alumina membranes has been studied with different ion counting methods using an energy dispersive electrostatic spectrometer, a multichannel plate (MCP) array and sensitive current-measurement. In the present work, we...

  6. Capillary Rise in a Wedge

    Piva, M.


    In introductory-level physics courses, the concept of surface tension is often illustrated using the example of capillary rise in thin tubes. In this paper the author describes experiments conducted using a planar geometry created with two small plates forming a thin wedge. The distribution of the fluid entering the wedge can be studied as a…

  7. Physico-chemical characterization of liposomes and drug substance-liposome interactions in pharmaceutics using capillary electrophoresis and electrokinetic chromatography

    Franzen, Ulrik; Østergaard, Jesper


    electrophoresis and liposome electrokinetic chromatography for the characterization of liposomes in a pharmaceutical context. Capillary electrophoretic techniques have been used for the measurement of electrophoretic mobility, which provides information on liposome surface charge, size and membrane permeability...... of liposomes. The use of liposome electrokinetic chromatography and capillary electrophoresis for determination of liposome/water partitioning and characterization of drug-liposome interactions is reviewed. A number of studies indicate that capillary electrophoresis may have a role in the...... characterization of liposome drug delivery systems, e.g., for the investigation of encapsulation efficiency and drug leakage. The well-known characteristics of capillary electrophoresis, i.e., low sample volume requirement, high separation efficiency in aqueous media without a stationary phase, minimal sample...

  8. Pulmonary epithelial permeability is immediately increased after embolisation with oleic acid but not with neutral fat.

    Jones, J G; Minty, B D; Beeley, J. M.; Royston, D; Crow, J; Grossman, R F


    Pulmonary fat embolism occurs frequently after trauma but its functional significance is often unclear. To obtain direct evidence of lung damage caused by fat embolism we have measured changes in permeability of the alveolar-capillary interface. A permeability index was derived from the half time clearance from lung to blood (T1/2LB) of 99mTcDTPA introduced into the lung in a 1 ml bolus. Three groups of rabbits were studied. Baseline T1/2LB. did not differ significantly between groups. After ...

  9. Electrokinetic effects and fluid permeability

    G. Berryman, James


    Fluid permeability of porous media depends mainly on connectivity of the pore space and two physical parameters: porosity and a pertinent length-scale parameter. Electrical imaging methods typically establish connectivity and directly measure electrical conductivity, which can then often be related to porosity by Archie's law. When electrical phase measurements are made in addition to the amplitude measurements, information about the pertinent length scale can then be obtained. Since fluid permeability controls the ability to flush unwanted fluid contaminants from the subsurface, inexpensive maps of permeability could improve planning strategies for remediation efforts. Detailed knowledge of fluid permeability is also important for oil field exploitation, where knowledge of permeability distribution in three dimensions is a common requirement for petroleum reservoir simulation and analysis, as well as for estimates on the economics of recovery.

  10. Water permeability of elastomers.

    Held, H R; Landi, S


    In a previous study it has been shown that the free moisture content in freeze-dried BCG vaccine dispensed in vials sealed with rubber stoppers increased during storage. The search for the source of this increase led us to explore the possibility that this additional moisture could originate from the rubber stoppers themselves. Therefore, the water permeability of various rubber stoppers has been studied, and the water content of grey butyl stoppers during some operations (autoclaving, oven-drying, freeze-drying, storage) used in the manufacturing of BCG vaccine has been determined. Our experiments showed: rapid water uptake during steam-autoclaving and rapid water release during subsequent oven-drying of the stoppers; a slow water uptake of the stoppers during freeze-drying and a slow water permeation through the stoppers when vials containing Indicating Drierite were stored in a water-saturated atmosphere. Among 12 types of rubber stoppers tested, the grey butyl stoppers and the silicone stoppers showed the lowest water uptake. Moisture-resistant wrappings decreased significantly the moisture uptake of Drierite. To delay moisture from reaching the vaccine it is recommended that the stoppers employed be as dry as possible. PMID:881425

  11. Myeloid tissue factor does not modulate lung inflammation or permeability during experimental acute lung injury

    Shaver, Ciara M.; Grove, Brandon S.; Clune, Jennifer K.; Nigel Mackman; Lorraine B. Ware; Bastarache, Julie A


    Tissue factor (TF) is a critical mediator of direct acute lung injury (ALI) with global TF deficiency resulting in increased airspace inflammation, alveolar-capillary permeability, and alveolar hemorrhage after intra-tracheal lipopolysaccharide (LPS). In the lung, TF is expressed diffusely on the lung epithelium and intensely on cells of the myeloid lineage. We recently reported that TF on the lung epithelium, but not on myeloid cells, was the major source of TF during intra-tracheal LPS-indu...

  12. Reinforcing endothelial junctions prevents microvessel permeability increase and tumor cell adhesion in microvessels in vivo

    Fu, Bingmei M.; Yang, Jinlin; Cai, Bin; Fan, Jie; Zhang, Lin; Zeng, Min


    Tumor cell adhesion to the microvessel wall is a critical step during tumor metastasis. Vascular endothelial growth factor (VEGF), a secretion of tumor cells, can increase microvessel permeability and tumor cell adhesion in the microvessel. To test the hypothesis that inhibiting permeability increase can reduce tumor cell adhesion, we used in vivo fluorescence microscopy to measure both microvessel permeability and adhesion rates of human mammary carcinoma MDA-MB-231 cells in post-capillary venules of rat mesentery under the treatment of VEGF and a cAMP analog, 8-bromo-cAMP, which can decrease microvessel permeability. By immunostaining adherens junction proteins between endothelial cells forming the microvessel wall, we further investigated the structural mechanism by which cAMP abolishes VEGF-induced increase in microvessel permeability and tumor cell adhesion. Our results demonstrate that 1) Pretreatment of microvessels with cAMP can abolish VEGF-enhanced microvessel permeability and tumor cell adhesion; 2) Tumor cells prefer to adhere to the endothelial cell junctions instead of cell bodies; 3) VEGF increases microvessel permeability and tumor cell adhesion by compromising endothelial junctions while cAMP abolishes these effects of VEGF by reinforcing the junctions. These results suggest that strengthening the microvessel wall integrity can be a potential approach to inhibiting hematogenous tumor metastasis.

  13. Permeability testing of biomaterial membranes

    Dreesmann, L; Hajosch, R; Nuernberger, J Vaz; Schlosshauer, B [NMI Natural and Medical Sciences Institute at University Tuebingen, Markwiesenstr. 55, D-72770 Reutlingen (Germany); Ahlers, M [GELITA AG, Gammelsbacher Str. 2, D-69412 Eberbach (Germany)], E-mail:


    The permeability characteristics of biomaterials are critical parameters for a variety of implants. To analyse the permeability of membranes made from crosslinked ultrathin gelatin membranes and the transmigration of cells across the membranes, we combined three technical approaches: (1) a two-chamber-based permeability assay, (2) cell culturing with cytochemical analysis and (3) biochemical enzyme electrophoresis (zymography). Based on the diffusion of a coloured marker molecule in conjunction with photometric quantification, permeability data for a gelatin membrane were determined in the presence or absence of gelatin degrading fibroblasts. Cytochemical evaluation after cryosectioning of the membranes was used to ascertain whether fibroblasts had infiltrated the membrane inside. Zymography was used to investigate the potential release of proteases from fibroblasts, which are known to degrade collagen derivatives such as gelatin. Our data show that the diffusion equilibrium of a low molecular weight dye across the selected gelatin membrane is approached after about 6-8 h. Fibroblasts increase the permeability due to cavity formation in the membrane inside without penetrating the membrane for an extended time period (>21 days in vitro). Zymography indicates that cavity formation is most likely due to the secretion of matrix metalloproteinases. In summary, the combination of the depicted methods promises to facilitate a more rational development of biomaterials, because it provides a rapid means of determining permeability characteristics and bridges the gap between descriptive methodology and the mechanistic understanding of permeability alterations due to biological degradation.

  14. Permeability testing of biomaterial membranes

    The permeability characteristics of biomaterials are critical parameters for a variety of implants. To analyse the permeability of membranes made from crosslinked ultrathin gelatin membranes and the transmigration of cells across the membranes, we combined three technical approaches: (1) a two-chamber-based permeability assay, (2) cell culturing with cytochemical analysis and (3) biochemical enzyme electrophoresis (zymography). Based on the diffusion of a coloured marker molecule in conjunction with photometric quantification, permeability data for a gelatin membrane were determined in the presence or absence of gelatin degrading fibroblasts. Cytochemical evaluation after cryosectioning of the membranes was used to ascertain whether fibroblasts had infiltrated the membrane inside. Zymography was used to investigate the potential release of proteases from fibroblasts, which are known to degrade collagen derivatives such as gelatin. Our data show that the diffusion equilibrium of a low molecular weight dye across the selected gelatin membrane is approached after about 6-8 h. Fibroblasts increase the permeability due to cavity formation in the membrane inside without penetrating the membrane for an extended time period (>21 days in vitro). Zymography indicates that cavity formation is most likely due to the secretion of matrix metalloproteinases. In summary, the combination of the depicted methods promises to facilitate a more rational development of biomaterials, because it provides a rapid means of determining permeability characteristics and bridges the gap between descriptive methodology and the mechanistic understanding of permeability alterations due to biological degradation

  15. Relative Permeability of Fractured Rock

    Mark D. Habana


    Contemporary understanding of multiphase flow through fractures is limited. Different studies using synthetic fractures and various fluids have yielded different relative permeability-saturation relations. This study aimed to extend the understanding of multiphase flow by conducting nitrogen-water relative permeability experiments on a naturally-fractured rock from The Geysers geothermal field. The steady-state approach was used. However, steady state was achieved only at the endpoint saturations. Several difficulties were encountered that are attributed to phase interference and changes in fracture aperture and surface roughness, along with fracture propagation/initiation. Absolute permeabilities were determined using nitrogen and water. The permeability values obtained change with the number of load cycles. Determining the absolute permeability of a core is especially important in a fractured rock. The rock may change as asperities are destroyed and fractures propagate or st rain harden as the net stresses vary. Pressure spikes occurred in water a solute permeability experiments. Conceptual models of an elastic fracture network can explain the pressure spike behavior. At the endpoint saturations the water relative permeabilities obtained are much less than the nitrogen gas relative permeabilities. Saturations were determined by weighing and by resistivity calculations. The resistivity-saturation relationship developed for the core gave saturation values that differ by 5% from the value determined by weighing. Further work is required to complete the relative permeability curve. The steady-state experimental approach encountered difficulties due to phase interference and fracture change. Steady state may not be reached until an impractical length of time. Thus, unsteady-state methods should be pursued. In unsteady-state experiments the challenge will be in quantifying rock fracture change in addition to fluid flow changes.

  16. Reservoir condition special core analyses and relative permeability measurements on Almond formation and Fontainebleu sandstone rocks

    Maloney, D.


    This report describes the results from special core analyses and relative permeability measurements conducted on Almond formation and Fontainebleu sandstone plugs. Almond formation plug tests were performed to evaluate multiphase, steady-state,reservoir-condition relative permeability measurement techniques and to examine the effect of temperature on relative permeability characteristics. Some conclusions from this project are as follows: An increase in temperature appeared to cause an increase in brine relative permeability results for an Almond formation plug compared to room temperature results. The plug was tested using steady-state oil/brine methods. The oil was a low-viscosity, isoparaffinic refined oil. Fontainebleu sandstone rock and fluid flow characteristics were measured and are reported. Most of the relative permeability versus saturation results could be represented by one of two trends -- either a k{sub rx} versus S{sub x} or k{sub rx} versus Sy trend where x and y are fluid phases (gas, oil, or brine). An oil/surfactant-brine steady-state relative permeability test was performed to examine changes in oil/brine relative permeability characteristics from changes in fluid IFTS. It appeared that, while low interfacial tension increased the aqueous phase relative permeability, it had no effect on the oil relative permeability. The BOAST simulator was modified for coreflood simulation. The simulator was useful for examining effects of variations in relative permeability and capillary pressure functions. Coreflood production monitoring and separator interface level measurement techniques were developed using X-ray absorption, weight methods, and RF admittance technologies. The three types of separators should be useful for routine and specialized core analysis applications.

  17. Direct measurement of the wetting front capillary pressure in a clay brick ceramic

    The absorption of a liquid into a rectangular bar of an initially dry porous material that is sealed on all surfaces except the inflow face is analysed in terms of Sharp Front theory. Sharp Front models are developed for both complete and incomplete displacement of air ahead of the advancing wetting front. Experiments are described from which a characteristic capillary potential of the material is obtained by measuring the equilibrium pressure of the air displaced and compressed ahead of the advancing wetting front. Results for the absorption of water and n-heptane by a fired clay brick ceramic suggest that this wetting front capillary pressure (or capillary potential) scales approximately with the surface tension and also that the permeability scales inversely with the liquid viscosity. The pressure of the air trapped in the wetted region is found to be the same as the pressure of the displaced air. For this material the wetting front capillary pressure for water at 20 C is 0.113 MPa, equivalent to a hydraulic tension head of 11.5 m and to a Young-Laplace pore diameter of 2.6 μm. The capillary pressure so measured is apparently a fundamental percolation property of the material that can be interpreted as the air pressure at which liquid phase continuity and unsaturated conductivity both vanish. The method described can be applied generally to porous materials

  18. Capillary hemangioma of palatal mucosa

    Bharti, Vipin; Singh, Jagmohan


    Hemangiomas are common tumors characterized microscopically by proliferation of blood vessels. The congenital hemangioma is often present at birth and may become more apparent throughout life. They are probably developmental rather than neoplastic in origin. Despite their benign origin and behavior, hemangiomas in the oral cavity are always of clinical importance to the dental profession and require appropriate clinical management. This case report presents a case of capillary hemangioma of a...

  19. Exponential asymptotics and capillary waves

    Chapman, S. J.; Vanden-Broeck, J.


    Recently developed techniques in exponential asymptotics beyond all orders are employed on the problem of potential flows with a free surface and small surface tension, in the absence of gravity. Exponentially small capillary waves are found to be generated on the free surface where the equipotentials from singularities in the flow (for example, stagnation points and corners) meet it. The amplitude of these waves is determined, and the implications are considered for many quite general flows....

  20. Nonlinear waves in capillary electrophoresis

    Ghosal, Sandip; Chen, Zhen


    Electrophoretic separation of a mixture of chemical species is a fundamental technique of great usefulness in biology, health care and forensics. In capillary electrophoresis the sample migrates in a microcapillary in the presence of a background electrolyte. When the ionic concentration of the sample is sufficiently high, the signal is known to exhibit features reminiscent of nonlinear waves including sharp concentration ‘shocks’. In this paper we consider a simplified model consisting of a ...

  1. Inertial Rise in Short Capillaries

    Shardt, Orest; Derksen, J J; Mitra, Sushanta K


    In this fluid dynamics video we show capillary rise experiments with diethyl ether in short tubes. The height of each short tube is less than the maximum height the liquid can achieve, and therefore the liquid reaches the top of the tube while still rising. Over a narrow range of heights, the ether bulges out from the top of the tube and spreads onto the external wall.

  2. Experimental study of heterogeneity-induced capillary trapping in the context of leakage from geologic carbon sequestration sites

    Liang, B.; Clarens, A. F.


    Leakage of CO2 from geologic carbon sequestration sites could undermine the long-term goal of reducing emissions to the atmosphere. Despite this, leakage processes, especially the vertical transport of gases through geologic formations overlaying target repositories, are poorly characterized. The goal of this work was to experimentally assess how sub-basin scale heterogeneity in overlaying formations could reduce CO2 leakage. High-pressure columns packed with sand and glass beads of different sizes were used to create a capillary barrier, which is an analog of low-permeability inter-beds. Transport of the resulting plume was recorded in real time using electrical resistivity. The effect of pressure, temperature, permeability, surface wettability, and CO2 flow rate were all assessed. Real-time monitoring and quantification of CO2 saturation suggests that capillary heterogeneity trapping is primarily controlled by permeability contrast, pressure, temperature and water/CO2 wettability on mineral surfaces. The amount of trapping was considerably enhanced when permeability contrasted increased, showing a good agreement with equilibrium capillary pressure - saturation analysis in the literature. Temperature and pressure controlled experiments demonstrated the sensitivity of capillary trapping to geothermal and pressure gradient. Wettability alterations also increased initial trapping when more CO2-philic materials is presented and a much greater increase in residual trapping (defined as 10 pore volume water re-imbibition). Variation of leakage rate was not shown to result in significant difference in the overall saturation values, but the stability of the trapped plume was reduced at high CO2 injection rates. These results suggest that local capillary trapping could contribute to secondary trapping and slow the buoyancy-driven rise of CO2. These measurements could have important implications for minimizing risk associated with leakage from carbon sequestration sites.

  3. Treelike networks accelerating capillary flow

    Shou, Dahua; Ye, Lin; Fan, Jintu


    Transport in treelike networks has received wide attention in natural systems, oil recovery, microelectronic cooling systems, and textiles. Existing studies are focused on transport behaviors under a constant potential difference (including pressure, temperature, and voltage) in a steady state [B. Yu and B. Li, Phys. Rev. E 73, 066302 (2006), 10.1103/PhysRevE.73.066302; J. Chen, B. Yu, P. Xu, and Y. Li, Phys. Rev. E 75, 056301 (2007), 10.1103/PhysRevE.75.056301]. However, dynamic (time-dependent) transport in such systems has rarely been concerned. In this work, we theoretically investigate the dynamics of capillary flow in treelike networks and design the distribution of radius and length of local branches for the fastest capillary flow. It is demonstrated that capillary flow in the optimized tree networks is faster than in traditional parallel tube nets under fixed constraints. As well, the flow time of the liquid is found to increase approximately linearly with penetration distance, which differs from Washburn's classic description that flow time increases as the square of penetration distance in a uniform tube.

  4. Estimation of permeability of a sandstone reservoir by a fractal and Monte Carlo simulation approach: a case study

    Vadapalli, U.; Srivastava, R. P.; Vedanti, N.; Dimri, V. P.


    Permeability of a hydrocarbon reservoir is usually estimated from core samples in the laboratory or from well test data provided by the industry. However, such data is very sparse and as such it takes longer to generate that. Thus, estimation of permeability directly from available porosity logs could be an alternative and far easier approach. In this paper, a method of permeability estimation is proposed for a sandstone reservoir, which considers fractal behavior of pore size distribution and tortuosity of capillary pathways to perform Monte Carlo simulations. In this method, we consider a reservoir to be a mono-dispersed medium to avoid effects of micro-porosity. The method is applied to porosity logs obtained from Ankleshwar oil field, situated in the Cambay basin, India, to calculate permeability distribution in a well. Computed permeability values are in good agreement with the observed permeability obtained from well test data. We also studied variation of permeability with different parameters such as tortuosity fractal dimension (Dt), grain size (r) and minimum particle size (d0), and found that permeability is highly dependent upon the grain size. This method will be extremely useful for permeability estimation, if the average grain size of the reservoir rock is known.

  5. Progression of Diabetic Capillary Occlusion: A Model.

    Xiao Fu


    Full Text Available An explanatory computational model is developed of the contiguous areas of retinal capillary loss which play a large role in diabetic maculapathy and diabetic retinal neovascularization. Strictly random leukocyte mediated capillary occlusion cannot explain the occurrence of large contiguous areas of retinal ischemia. Therefore occlusion of an individual capillary must increase the probability of occlusion of surrounding capillaries. A retinal perifoveal vascular sector as well as a peripheral retinal capillary network and a deleted hexagonal capillary network are modelled using Compucell3D. The perifoveal modelling produces a pattern of spreading capillary loss with associated macular edema. In the peripheral network, spreading ischemia results from the progressive loss of the ladder capillaries which connect peripheral arterioles and venules. System blood flow was elevated in the macular model before a later reduction in flow in cases with progression of capillary occlusions. Simulations differing only in initial vascular network structures but with identical dynamics for oxygen, growth factors and vascular occlusions, replicate key clinical observations of ischemia and macular edema in the posterior pole and ischemia in the retinal periphery. The simulation results also seem consistent with quantitative data on macular blood flow and qualitative data on venous oxygenation. One computational model applied to distinct capillary networks in different retinal regions yielded results comparable to clinical observations in those regions.

  6. Predicting permeability and electrical conductivity of sedimentary rocks from microgeometry

    The determination of hydrologic parameters that characterize fluid flow through rock masses on a large scale (e.g., hydraulic conductivity, capillary pressure, and relative permeability) is crucial to activities such as the planning and control of enhanced oil recovery operations, and the design of nuclear waste repositories. Hydraulic permeability and electrical conductivity of sedimentary rocks are predicted from the microscopic geometry of the pore space. The cross-sectional areas and perimeters of the individual pores are estimated from two-dimensional scanning electron micrographs of rock sections. The hydraulic and electrical conductivities of the individual pores are determined from these geometrical parameters, using Darcy's law and Ohm's law. Account is taken of the fact that the cross-sections are randomly oriented with respect to the channel axes, and for possible variation of cross-sectional area along the length of the pores. The effective medium theory from solid-state physics is then used to determine an effective average conductance of each pore. Finally, the pores are assumed to be arranged on a cubic lattice, which allows the calculation of overall macroscopic values for the permeability and the electrical conductivity. Preliminary results using Berea, Boise, Massilon and Saint-Gilles sandstones show reasonably close agreement between the predicted and measured transport properties. 12 refs., 5 figs., 1 tab

  7. Development of Acidizing Techniques for Low-permeability Carbonate Reservoirs

    Liu Tongbin


    @@ Geological Background In accordance with gas reservoir occurrence, reserve type and trap type, the discovered and developed carbonate reservoirs in Sichuan Basin can be classified into the following three types: the first type is the layered porous gas reservoir (including porous and fractured porous gas reservoir), mainly distributed in East Sichuan area; the second is the block vug bottom water drive gas reservoir; the third is the irregular gas reservoir with fracture system, mainly distributed in the areas of South Sichuan and Southwest Sichuan. The reservoirs of these gas pools are mainly of carbonatite. The matrix porosity and permeability of carbonatite are very low, the porosity being below 1% - 3% and the permeability, 0.1×10-3-8× 10-3 μm2. Also the throat capillary resistance force is considerable with the mid-value width of the throat (γ50)of 0.1 - 4 μm, most below 2 μm. Owing to the low permeability and porosity as well as the serious heterogeneity of the reservoir, the productivi ty of gas wells changes greatly.

  8. Geothermal Permeability Enhancement - Final Report

    Joe Beall; Mark Walters


    The overall objective is to apply known permeability enhancement techniques to reduce the number of wells needed and demonstrate the applicability of the techniques to other undeveloped or under-developed fields. The Enhanced Geothermal System (EGS) concept presented in this project enhances energy extraction from reduced permeability zones in the super-heated, vapor-dominated Aidlin Field of the The Geysers geothermal reservoir. Numerous geothermal reservoirs worldwide, over a wide temperature range, contain zones of low permeability which limit the development potential and the efficient recovery of heat from these reservoirs. Low permeability results from poorly connected fractures or the lack of fractures. The Enhanced Geothermal System concept presented here expands these technologies by applying and evaluating them in a systematic, integrated program.

  9. Permeability of soils in Mississippi

    O'Hara, Charles G.


    The permeability of soils in Mississippi was determined and mapped using a geographic information system (GIS). Soil permeabilities in Mississippi were determined to range in value from nearly 0.0 to values exceeding 5.0 inches per hour. The U.S. Soil Conservation Service's State Soil Geographic Data Base (STATSGO) was used as the primary source of data for the determination of area-weighted soil permeability. STATSGO provides soil layer properties that are spatially referenced to mapped areas. These mapped areas are referred to as polygons in the GIS. The polygons arc boundaries of soils mapped as a group and are given unique Map Unit Identifiers (MUIDs). The data describing the physical characteristics of the soils within each polygon are stored in a tabular data base format and are referred to as attributes. The U.S. Soil Conservation Service developed STATSGO to be primarily used as a guide for regional resource planning, management, and monitoring. STATSGO was designed so that soil information could be extracted from properties tables at the layer level, combined by component, and statistically expanded to cover the entire map unit. The results of this study provide a mapped value for permeability which is representative of the vertical permeability of soils in that area. The resultant permeability map provides a representative vertical soil permeability for a given area sufficient for county, multi- county, and area planning, and will be used as the soil permeability data component in the evaluation of the susceptibility of major aquifers to contami- nation in Mississippi.

  10. Permeability within basaltic oceanic crust

    Fisher, Andrew T.


    Water-rock interactions within the seafloor are responsible for significant energy and solute fluxes between basaltic oceanic crust and the overlying ocean. Permeability is the primary hydrologic property controlling the form, intensity, and duration of seafloor fluid circulation, but after several decades of characterizing shallow oceanic basement, we are still learning how permeability is created and distributed and how it changes as the crust ages. Core-scale measurements of basaltic oceanic crust yield permeabilities that are quite low (generally 10-22 to 10-17 m²), while in situ measurements in boreholes suggest an overlapping range of values extending several orders of magnitude higher (10-18 to 10-13 m²). Additional indirect estimates include calculations made from borehole temperature and flow meter logs (10-16 to 10-11 m²), numerical models of coupled heat and fluid flow at the ridge crest and within ridge flanks (10-16 to 10-9 m²), and several other methods. Qualitative indications of permeability within the basaltic oceanic crust come from an improved understanding of crustal stratigraphy and patterns of alteration and tectonic modification seen in ophiolites, seafloor samples and boreholes. Difficulties in reconciling the wide range of estimated permeabilities arise from differences in experimental scale and critical assumptions regarding the nature and distribution of fluid flow. Many observations and experimental and modeling results are consistent with permeability varying with depth into basement and with primary basement lithology. Permeability also seems to be highly heterogeneous and anisotropic throughout much of the basaltic crust, as within crystalline rocks in general. A series of focused experiments is required to resolve permeability in shallow oceanic basement and to directly couple upper crustal hydrogeology to magmatic, tectonic, and geochemical crustal evolution.

  11. An Experimental Study of CO2-Brine Relative Permeability in Sandstone

    Chen, X.; DiCarlo, D. A.


    Accurate determinations of CO2-brine relative permeability are important for modeling potential CO2 storage scenarios. The most common assumption is that CO2-brine relative permeability is likely to be similar to oil-brine relative permeability for water-wet rocks. But recent measurements of CO2-brine relative permeability have differed greatly from oil-brine relative permeability; particularly, the measurements show a very low CO2 end point relative permeability (kr,CO2=0.1~0.2) and a relatively high residual water saturation (Swr>0.4) ( Lee et al. 2010, Zuo et al. 2012, Akbarabadi et al. 2013 and etc.). It has been hypothesized that the differences are related to CO2-brine having a different contact angle from oil-brine. In this study, we hypothesize that the differences are caused by large capillary end effects resulted from the very low CO2 viscosity. We conduct steady-state CO2-brine flow experiments in 2-foot-long and 2.8-inch-diamter Berea sandstone cores at 20 °C and 1500 psi. Four pressure taps drilled on a core allow both the total pressure drop and that across five individual sections to be measured. Three experiments, two drainage and one imbibition, have been conducted so far. Our results show: (1) The relative permeability to both brine and CO2 of the last section (downstream, 15 cm long) is significantly smaller than that of any of the middle three sections. This testifies that the capillary end effect makes the relative permeability under-measured at the end of a core. (2) The values of the middle three sections are very close to each other, which indicate the middle part of our core is free of capillary end effect. (3) The CO2 end point relative permeability is 0.3~0.5, which is much higher than the recent measurements. (4) The brine end point relative permeability during imbibition is about 0.08, which is close to literature data. Reference: Lee, Y.S, Kim, K. H. and Lee, T.H. et al. Analysis of CO2 Endpoint Relative Permeability and Injectivity

  12. Capillary pumped loop body heat exchanger

    Swanson, Theodore D. (Inventor); Wren, deceased, Paul (Inventor)


    A capillary pumped loop for transferring heat from one body part to another body part, the capillary pumped loop comprising a capillary evaporator for vaporizing a liquid refrigerant by absorbing heat from a warm body part, a condenser for turning a vaporized refrigerant into a liquid by transferring heat from the vaporized liquid to a cool body part, a first tube section connecting an output port of the capillary evaporator to an input of the condenser, and a second tube section connecting an output of the condenser to an input port of the capillary evaporator. A wick may be provided within the condenser. A pump may be provided between the second tube section and the input port of the capillary evaporator. Additionally, an esternal heat source or heat sink may be utilized.

  13. Microfluidic PMMA interfaces for rectangular glass capillaries

    We present the design and fabrication of a polymeric capillary fluidic interface fabricated by micro-milling. The design enables the use of glass capillaries with any kind of cross-section in complex microfluidic setups. We demonstrate two different designs of the interface; a double-inlet interface for hydrodynamic focusing and a capillary interface with integrated pneumatic valves. Both capillary interfaces are presented together with examples of practical applications. This communication shows the design optimization and presents details of the fabrication process. The capillary interface opens up for the use of complex microfluidic systems in single-use glass capillaries. They also enable simple fabrication of glass/polymer hybrid devices that can be beneficial in many research fields where a pure polymer chip negatively affects the device's performance, e.g. acoustofluidics. (technical note)

  14. Monolithic molecularly imprinted polymeric capillary columns for isolation of aflatoxins.

    Szumski, Michał; Grzywiński, Damian; Prus, Wojciech; Buszewski, Bogusław


    Monolithic molecularly imprinted polymers extraction columns have been prepared in fused-silica capillaries by UV or thermal polymerization in a two-step process. First, a poly-(trimethylolpropane trimethacrylate) (polyTRIM) core monolith was synthesized either by UV or thermal polymerization. Then it was grafted with the mixture of methacrylic acid (MAA) as a functional monomer, ethylene dimethacrylate (EDMA) as a cross-linking agent, 5,7-dimethoxycoumarin (DMC) as an aflatoxin-mimicking template, toluene as a porogen solvent and 2,2-azobis-(2-methylpropionitrile) (AIBN) as an initiator of the polymerization reaction. Different thermal condition of the photografting and different concentrations of the grafting mixture were tested during polymerization. The extraction capillary columns were evaluated in the terms of their hydrodynamic and chromatographic properties. Retention coefficients for aflatoxin B1 and DMC were used for assessment of the selectivity and imprinting factor. The obtained results indicate that the temperature of photografting and concentration of the grafting mixture are key parameters that determine the quality of the prepared MIPs. From the MIP columns characterized by the highest permeability the column of the highest imprinting factor was applied for isolation of aflatoxins B1, B2, G1 and G2 from the model aqueous sample followed by on-line chromatographic separation. The process was performed using a micro-MISPE-microLC-LIF system of a novel design, which allowed for detection of the eluates from the sample preparation part as well as from the chromatographic separation. PMID:25218633

  15. DNA Sequencing Using capillary Electrophoresis

    Dr. Barry Karger


    The overall goal of this program was to develop capillary electrophoresis as the tool to be used to sequence for the first time the Human Genome. Our program was part of the Human Genome Project. In this work, we were highly successful and the replaceable polymer we developed, linear polyacrylamide, was used by the DOE sequencing lab in California to sequence a significant portion of the human genome using the MegaBase multiple capillary array electrophoresis instrument. In this final report, we summarize our efforts and success. We began our work by separating by capillary electrophoresis double strand oligonucleotides using cross-linked polyacrylamide gels in fused silica capillaries. This work showed the potential of the methodology. However, preparation of such cross-linked gel capillaries was difficult with poor reproducibility, and even more important, the columns were not very stable. We improved stability by using non-cross linked linear polyacrylamide. Here, the entangled linear chains could move when osmotic pressure (e.g. sample injection) was imposed on the polymer matrix. This relaxation of the polymer dissipated the stress in the column. Our next advance was to use significantly lower concentrations of the linear polyacrylamide that the polymer could be automatically blown out after each run and replaced with fresh linear polymer solution. In this way, a new column was available for each analytical run. Finally, while testing many linear polymers, we selected linear polyacrylamide as the best matrix as it was the most hydrophilic polymer available. Under our DOE program, we demonstrated initially the success of the linear polyacrylamide to separate double strand DNA. We note that the method is used even today to assay purity of double stranded DNA fragments. Our focus, of course, was on the separation of single stranded DNA for sequencing purposes. In one paper, we demonstrated the success of our approach in sequencing up to 500 bases. Other

  16. A fractal approach to low velocity non-Darcy flow in a low permeability porous medium

    In this paper, the mechanism for fluid flow at low velocity in a porous medium is analyzed based on plastic flow of oil in a reservoir and the fractal approach. The analytical expressions for flow rate and velocity of non-Newtonian fluid flow in the low permeability porous medium are derived, and the threshold pressure gradient (TPG) is also obtained. It is notable that the TPG (J) and permeability (K) of the porous medium analytically exhibit the scaling behavior J ∼ K−DT/(1=DT), where DT is the fractal dimension for tortuous capillaries. The fractal characteristics of tortuosity for capillaries should be considered in analysis of non-Darcy flow in a low permeability porous medium. The model predictions of TPG show good agreement with those obtained by the available expression and experimental data. The proposed model may be conducible to a better understanding of the mechanism for nonlinear flow in the low permeability porous medium. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  17. A New Conductivity Detector for Capillary Electrophoresis


    A new conductivity detector for capillary electrophoresis consisting of an electrochemical cell and a conductive meter was developed. In the cell, the microelectrode and capillary were inserted through the cell wall and fixed by screws and sealing ring, the ends of microelectrode and capillary were located by a guide with two cross holes. LOD for K+ was 1.5×10-5 mol/L.

  18. Serum proteins analysis by capillary electrophoresis

    Uji, Yoshinori; Okabe, Hiroaki


    The purpose of this study was to evaluate the efficacy of multi-capillary electrophoresis instrument in clinical laboratory. An automated clinical capillary electrophoresis system was evaluated for performing serum proteins electrophoresis and immuno-fixation electrophoresis by subtraction. In this study the performance of capillary electrophoresis was compared with the cellulose acetate membrane electrophoresis and agarose gel immunofixation electrophoresis for serum proteins. The results of...

  19. Cytokine Analysis by Immunoaffinity Capillary Electrophoresis

    Mendonca, Mark; Kalish, Heather


    Immunoaffinity capillary electrophoresis (ICE) is a powerful tool used to detect and quantify target proteins of interest in complex biological fluids. The target analyte is captured and bound to antibodies immobilized onto the wall of a capillary, labeled in situ with a fluorescent dye, eluted and detected online using laser-induced fluorescence following electrophoretic separation. Here, we illustrate how to construct an immunoaffinity capillary and utilize it to run ICE in order to capture...

  20. Slope wavenumber spectrum models of capillary and capillary-gravity waves

    贾永君; 张杰; 王岩峰


    Capillary and capillary-gravity waves possess a random character, and the slope wavenumber spectra of them can be used to represent mean distributions of wave energy with respect to spatial scale of variability. But simple and practical models of the slope wavenumber spectra have not been put forward so far. In this article, we address the accurate definition of the slope wavenumber spectra of water surface capillary and capillary-gravity waves. By combining the existing slope wavenumber models and using th...

  1. Radioisotope albumin flux measurement of microvascular lung permeability: an independent parameter in acute respiratory failure?

    Aim: To evaluate the extent to which single measurements of microvascular lung permeability may be relevant as an additional parameter in a heterogenous clinical patient collective with Acute Lung Injury (ALI) and Acute Respiratory Distress Syndrome (ARDS). Methods: In 36 patients with pneumonia (13), non pneumogenic sepsis (9) or trauma (14) meeting the consensus conference criteria of ALI or ARDS double-isotope protein flux measurements (51Cr erythrocytes as intravascular tracer, Tc-99m human albumin as diffusible tracer) of microvascular lung permeability were performed using the Normalized Slope Index (NSI). The examination was to determine whether there is a relationship between the clinical diagnosis of ALI/ARDS, impaired permeability and clinical parameters, that is the underlying disease, oxygenation, duration of mechanical ventilation and mean pulmonary-artery pressure (PAP). Results: At the time of study, 25 patients presented with increased permeability (NSI > 1 x 10-3 min-1) indicating an exudative stage of disease, and 11 patients with normal permeability. The permeability impairment correlated with the underlying disease (p > 0.05). With respect to survival, there was a negative correlation to PAP (p < 0.01). Apart from that no correlations between the individual parameters were found. Especially no correlation was found between permeability impairment and oxygenation, duration of disease of PAP. Conclusion: In ALI and ARDS, pulmonary capillary permeability is a diagnostic parameter which is independent from clinical variables. Permeability measurement makes a stage classification (exudative versus non exudative phase) of ALI/ARDS possible based on a measurable pathophysiological correlate. (orig.)

  2. Electromigration dispersion in Capillary Electrophoresis

    Chen, Zhen; 10.1007/s11538-011-9708-7


    In a previous paper (S. Ghosal and Z. Chen Bull. Math. Biol. 2010, vol. 72, pg. 2047) it was shown that the evolution of the solute concentration in capillary electrophoresis is described by a nonlinear wave equation that reduced to Burger's equation if the nonlinearity was weak. It was assumed that only strong electrolytes (fully dissociated) were present. In the present paper it is shown that the same governing equation also describes the situation where the electrolytic buffer consists of a single weak acid (or base). A simple approximate formula is derived for the dimensionless peak variance which is shown to agree well with published experimental data.

  3. Microbeam-coupled capillary electrophoresis

    Within the first few microseconds following a charged particle traversal of a cell, numerous oxygen and nitrogen radicals are formed along the track. Presented here is a method, using capillary electrophoresis, for simultaneous measurement, within an individual cell, of specific reactive oxygen species, such as the superoxide radical (O2-*) as well as the native and oxidised forms of glutathione, an ubiquitous anti-oxidant that assists the cell in coping with these species. Preliminary data are presented as well as plans for integrating this system into the charged particle microbeam at Columbia University. (authors)

  4. Capillary electrophoresis theory and practice

    Grossman, Paul D


    This book is designed to be a practical guide, used by wide audience, including those new to CE, those more experienced, routine users, those interested in technology development, and those involved with applications research. References have been emphasized to allow the reader to explore the detailed specifics and theoretical foundations.This book draws together the rapidly evolving, diverse, and multidisciplinary subject of capillary electrophoresis (CE). It is designed as a practical guide to be used by a wide audience, including those new to CE as well as more experienced users. T

  5. Exotic containers for capillary surfaces

    Concus, Paul; Finn, Robert


    This paper discusses 'exotic' rotationally symmetric containers that admit an entire continuum of distinct equilibrium capillary free surfaces. The paper extends earlier work to a larger class of parameters and clarifies and simplifies the governing differential equations, while expressing them in a parametric form appropriate for numerical integration. A unified presentation suitable for both zero and nonzero gravity is given. Solutions for the container shapes are depicted graphically along with members of the free-surface continuum, and comments are given concerning possible physical experiments.

  6. Geologic CO2 sequestration in saline aquifers accounting for dual permeability/porosity environments.

    Randolph, J. B.; Saar, M. O.


    The State of Minnesota, like many regions of the United States and beyond, has mandated significant reductions in CO2 emissions by mid-century, and geologic CO2 sequestration is recognized as one means by which to meet emissions goals. Unfortunately, the state, like many other regions, does not contain sedimentary basins that meet the currently established criteria for CO2 sequestration in deep saline aquifers. That is, existing basins, though expansive, are shallower (e.g., the Mount Simon aquifer in Minnesota) or less permeable (e.g., the Midcontinental Rift System) than sedimentary units that are typically considered for sequestration. The field of karst hydrogeology recognizes the importance of multiple permeability/porosity systems in groundwater transport and storage. High permeability fracture networks permit rapid groundwater transport while the large, lower permeability matrix allows for significant storage. With this motivation, we develop a geologic CO2 sequestration model, using TOUGH2 and TOUGHREACT, which accounts for the presence of multiple permeability/porosity structures. Capillary forces play an important role in these multiphase, multi-permeability and porosity systems. Our preliminary models investigate whether the Midcontinental Rift System could prove a viable candidate for geologic CO2 sequestration, should suitable fracture networks (among other criteria) be located there.

  7. Air permeability of polyester nonwoven fabrics

    Zhu Guocheng; Kremenakova Dana; Wang Yan; Militky Jiri


    Air permeability is one of the most important properties of non-woven fabrics in many applications. This paper aims to investigate the effects of thickness, porosity and density on the air permeability of needle-punched non-woven fabrics and compare the experimental values with two models which are based on hydraulic radius theory and drag theory, respectively. The air permeability of the samples was measured by an air permeability tester FX3300. The results showed that the air permeability o...

  8. Computational micro-scale model of control of extravascular water and capillary perfusion in the air blood barrier.

    Mazzuca, Enrico; Aliverti, Andrea; Miserocchi, Giuseppe


    A computational model of a morphologically-based alveolar capillary unit (ACU) in the rabbit is developed to relate lung fluid balance to mechanical forces between capillary surface and interstitium during development of interstitial edema. We hypothesize that positive values of interstitial liquid pressure Pliq impact on capillary transmural pressure and on blood flow. ACU blood flow, capillary recruitment and filtration are computed by modulating vascular and interstitial pressures. Model results are compared with experimental data of Pliq increasing from ~-10 (control) up to ~4cmH2O in two conditions, hypoxia and collagenase injection. For hypoxia exposure, fitting data requires a linear increase in hydraulic conductivity Lp and capillary pressure PC, that fulfils the need of increase in oxygen delivery. For severe fragmentation of capillary endothelial barrier (collagenase injection), fitting requires a rapid increase in both hydraulic and protein permeability, causing ACU de-recruitment, followed by an increase in PC as a late response to restore blood flow. In conclusion, the model allows to describe the lung adaptive response to edemagenic perturbations; the increase in Pliq, related to the low interstitial compliance, provides an efficient control of extravascular water, by limiting microvascular filtration. PMID:27059893

  9. Water Tank with Capillary Air/Liquid Separation

    Ungar, Eugene K.; Smith, Frederick; Edeen, Gregg; Almlie, Jay C.


    A bladderless water tank (see figure) has been developed that contains capillary devices that allow it to be filled and emptied, as needed, in microgravity. When filled with water, the tank shields human occupants of a spacecraft against cosmic radiation. A membrane that is permeable by air but is hydrophobic (neither wettable nor permeable by liquid water) covers one inside surface of the tank. Grooves between the surface and the membrane allow air to flow through vent holes in the surface as the tank is filled or drained. A margin of wettable surface surrounds the edges of the membrane, and all the other inside tank surfaces are also wettable. A fill/drain port is located in one corner of the tank and is covered with a hydrophilic membrane. As filling begins, water runs from the hydrophilic membrane into the corner fillets of the tank walls. Continued filling in the absence of gravity will result in a single contiguous air bubble that will be vented through the hydrophobic membrane. The bubble will be reduced in size until it becomes spherical and smaller than the tank thickness. Draining the tank reverses the process. Air is introduced through the hydrophobic membrane, and liquid continuity is maintained with the fill/drain port through the corner fillets. Even after the tank is emptied, as long as the suction pressure on the hydrophilic membrane does not exceed its bubble point, no air will be drawn into the liquid line.

  10. Permeability enhancement by shock cooling

    Griffiths, Luke; Heap, Michael; Reuschlé, Thierry; Baud, Patrick; Schmittbuhl, Jean


    The permeability of an efficient reservoir, e.g. a geothermal reservoir, should be sufficient to permit the circulation of fluids. Generally speaking, permeability decreases over the life cycle of the geothermal system. As a result, is usually necessary to artificially maintain and enhance the natural permeability of these systems. One of the methods of enhancement -- studied here -- is thermal stimulation (injecting cold water at low pressure). This goal of this method is to encourage new thermal cracks within the reservoir host rocks, thereby increasing reservoir permeability. To investigate the development of thermal microcracking in the laboratory we selected two granites: a fine-grained (Garibaldi Grey granite, grain size = 0.5 mm) and a course-grained granite (Lanhelin granite, grain size = 2 mm). Both granites have an initial porosity of about 1%. Our samples were heated to a range of temperatures (100-1000 °C) and were either cooled slowly (1 °C/min) or shock cooled (100 °C/s). A systematic microstructural (2D crack area density, using standard stereological techniques, and 3D BET specific surface area measurements) and rock physical property (porosity, P-wave velocity, uniaxial compressive strength, and permeability) analysis was undertaken to understand the influence of slow and shock cooling on our reservoir granites. Microstructurally, we observe that the 2D crack surface area per unit volume and the specific surface area increase as a result of thermal stressing, and, for the same maximum temperature, crack surface area is higher in the shock cooled samples. This observation is echoed by our rock physical property measurements: we see greater changes for the shock cooled samples. We can conclude that shock cooling is an extremely efficient method of generating thermal microcracks and modifying rock physical properties. Our study highlights that thermal treatments are likely to be an efficient method for the "matrix" permeability enhancement of

  11. Ultrastructural changes in the optic nerve and capillary vessels during early stages of optic nerve injury

    Xuehong Ju; Xiuyun Li; Xiaoshuang Li; Hongtao Tang; Hongguo Liu


    were observed. At 6 hours, medullary and vacuolar degeneration in the mitochondria, and swollen endothelial cells in the capillary, were visible. At 12 hours, these changes were more obvious. At 48 hours, granular dissolution of microtubules, micro filaments, and mitochondria, as well as diffuse degeneration of mitochondria in the endothelial cells, were observed. At 96 hours, axonal disintegration, vacuolar degeneration, and dilated capillaries were observed. CONCLUSION: During early stages, the injured intracanalicular optic nerve exhibited swollen axons with vacuolar degeneration, swollen and degenerated mitochondria, decreased number of microtubules and microfilaments, and dilated capillaries with increased permeability.

  12. Sheathless interface for coupling capillary electrophoresis with mass spectrometry

    Wang, Chenchen; Tang, Keqi; Smith, Richard D.


    A sheathless interface for coupling capillary electrophoresis (CE) with mass spectrometry is disclosed. The sheathless interface includes a separation capillary for performing CE separation and an emitter capillary for electrospray ionization. A portion of the emitter capillary is porous or, alternatively, is coated to form an electrically conductive surface. A section of the emitter capillary is disposed within the separation capillary, forming a joint. A metal tube, containing a conductive liquid, encloses the joint.

  13. Diagnostics of a high current capillary discharge

    We have demonstrated that thin (10 to 25 μm diameter) capillaries can be fabricated in suitably configured insulators for use in pulse power machines. Large currents can be used to heat these capillaries which produce photons with an energies greater than 1 keV

  14. Pulmonary capillary haemangiomatosis in a premature infant

    Pulmonary capillary haemangiomatosis (PCH) is a rare disorder characterized by widespread capillary proliferation in the lung, infiltrating the interstitium and the alveolar walls. We present the HRCT features of PCH in a surviving ex-premature infant. To our knowledge, this is a unique case of the radiological features of PCH in a young living infant. (orig.)

  15. Pulmonary capillary haemangiomatosis in a premature infant

    Silva, Cicero J.T.A.; Massie, John; Mandelstam, Simone A. [University of Melbourne, Royal Children' s Hospital, Parkville, VIC (Australia)


    Pulmonary capillary haemangiomatosis (PCH) is a rare disorder characterized by widespread capillary proliferation in the lung, infiltrating the interstitium and the alveolar walls. We present the HRCT features of PCH in a surviving ex-premature infant. To our knowledge, this is a unique case of the radiological features of PCH in a young living infant. (orig.)

  16. Increased cardiac index due to terbutaline treatment aggravates capillary-alveolar macromolecular leakage in oleic acid lung injury in dogs

    Briot, Raphael; Bayat, Sam; Anglade, Daniel; Martiel, Jean-Louis; Grimbert, Francis


    Introduction We assessed the in vivo effects of terbutaline, a beta2-agonist assumed to reduce microvascular permeability in acute lung injury. Methods We used a recently developed broncho-alveolar lavage (BAL) technique to repeatedly measure (every 15 min. for 4 hours) the time-course of capillary-alveolar leakage of a macromolecule (fluorescein-labeled dextran) in 19 oleic acid (OA) lung injured dogs. BAL was performed in a closed lung sampling site, using a bronchoscope fitted with an infl...

  17. Autoradiographic study of the permeability characteristics of the small intestine

    This autoradiographic study demonstrates the distribution of a range of small solutes and macromolecules in the mucosa of the guinea-pig small intestine after intracardiac injection. The substances investigated were: 14C-urea, 3H-mannose, 3H-inulin, and 125I polyvinylpyrrolidone (PVP). Small bowel biopsies were taken at intervals from one to 60 minutes after injection and the tissues processed for autoradiography. Light microscopic examination of the autoradiographs showed that the compartmental distribution depended on the molecular size of the substances being studied. Urea and mannose, as small solutes, were uniformly distributed throughout the intravascular, extravascular, and epithelial compartments. Inulin was evenly distributed in the vessel lumen and extravascular space but there was a considerable drop in concentration in the epithelium. PVP exhibited the most marked gradients, the concentration being greatest in the vascular lumina, lower in the extravascular space, least in the epithelium. Thus there appear to be two barriers to macromolecular passage which are freely permeable to small solutes: the capillary wall and the epithelium. At a light microscopical level it was not possible to observe whether the limiting membrane of each of these barriers is the cell plasmalemmal membrane or the basement membrane. The selectivity of the epithelial barrier was greater than that of the capillary barrier. (author)

  18. Capillary Discharge XUV Radiation Source

    M. Nevrkla


    Full Text Available A device producing Z-pinching plasma as a source of XUV radiation is described. Here a ceramic capacitor bank pulse-charged up to 100 kV is discharged through a pre-ionized gas-filled ceramic tube 3.2 mm in diameter and 21 cm in length. The discharge current has amplitude of 20 kA and a rise-time of 65 ns. The apparatus will serve as experimental device for studying of capillary discharge plasma, for testing X-ray optics elements and for investigating the interaction of water-window radiation with biological samples. After optimization it will be able to produce 46.9 nm laser radiation with collision pumped Ne-like argon ions active medium. 

  19. High membrane permeability for melatonin.

    Yu, Haijie; Dickson, Eamonn J; Jung, Seung-Ryoung; Koh, Duk-Su; Hille, Bertil


    The pineal gland, an endocrine organ in the brain, synthesizes and secretes the circulating night hormone melatonin throughout the night. The literature states that this hormone is secreted by simple diffusion across the pinealocyte plasma membrane, but a direct quantitative measurement of membrane permeability has not been made. Experiments were designed to compare the cell membrane permeability to three indoleamines: melatonin and its precursors N-acetylserotonin (NAS) and serotonin (5-HT). The three experimental approaches were (1) to measure the concentration of effluxing indoleamines amperometrically in the bath while cells were being dialyzed internally by a patch pipette, (2) to measure the rise of intracellular indoleamine fluorescence as the compound was perfused in the bath, and (3) to measure the rate of quenching of intracellular fura-2 dye fluorescence as indoleamines were perfused in the bath. These measures showed that permeabilities of melatonin and NAS are high (both are uncharged molecules), whereas that for 5-HT (mostly charged) is much lower. Comparisons were made with predictions of solubility-diffusion theory and compounds of known permeability, and a diffusion model was made to simulate all of the measurements. In short, extracellular melatonin equilibrates with the cytoplasm in 3.5 s, has a membrane permeability of ∼1.7 µm/s, and could not be retained in secretory vesicles. Thus, it and NAS will be "secreted" from pineal cells by membrane diffusion. Circumstances are suggested when 5-HT and possibly catecholamines may also appear in the extracellular space passively by membrane diffusion. PMID:26712850

  20. Albuminuria and overall capillary permeability of albumin in acute altitude hypoxia

    Hansen, J M; Olsen, N V; Feldt-Rasmussen, B;


    groups. Exercise did not reveal any further renal dysfunction. In both groups, high altitude increased TERalb from 4.8 to > 6.7%/h (P < 0.05). In conclusion, acute altitude hypoxia increases Ualb despite unchanged tubular function and independent of effects of isradipine on filtration fraction. The......The mechanism of proteinuria at high altitude is unclear. Renal function and urinary excretion rate of albumin (Ualb) at rest and during submaximal exercise and transcapillary escape rate of 125I-labeled albumin (TERalb) were investigated in 12 normal volunteers at sea level and after rapid and...... passive ascent to 4,350 m. The calcium antagonist isradipine (5 mg/day; n = 6) or placebo (n = 6) was administered to abolish hypoxia-induced rises in blood pressure. Lithium clearance and urinary excretion of beta 2-microglobulin were used to evaluate renal tubular function. High altitude increased Ualb...

  1. Tissue to plasma capillary permeability of 131I-albumin in the perfused rabbit ear

    Bent-Hansen, L; Svendsen, Jesper Hastrup


    The tissue to plasma transfer of 131I-albumin was recorded in perfused rabbit ears (n = 6) following equilibration for 24 hr. 125I-fibrinogen served as the plasma marker, and was introduced intravenously 15 min before clamping. The ears were rollerpump perfused with isotonic diluted plasma at a...

  2. User's Guide for Hysteretic Capillary Pressure and Relative Permeability Functions in TOUGH2

    Doughty, C. A.


    This document provides a user’s guide for the most recent version of the hysteretic code, which runs within iTOUGH2 (Finsterle, 1999a,b,c) or TOUGH2 V2.1 (Pruess et al., 2012). The usage of the hysteretic module is the same in both codes, which for brevity here are both referred to simply as TOUGH2. The current code differs only slightly from what was presented in Doughty (2007), hence that document provides the basic information on the processes being modeled and how they are conceptualized. This document focuses on a description of the user-specified parameters required to run hysteretic TOUGH2. In the few instances where the conceptualization differs from that of Doughty (2007), the features described here are the current ones. Sample problems presented in this user’s guide use the equation-of-state module ECO2N (Pruess, 2005). The components present in ECO2N are H{sub 2}O, NaCl, and CO{sub 2}. Two fluid phases and one solid phase are considered: an aqueous phase, which primarily consists of liquid H{sub 2}O and may contain dissolved NaCl and CO{sub 2}; a supercritical phase which primarily consists of CO{sub 2}, but also includes a small amount of gaseous H{sub 2}O; and a solid phase consisting of precipitated NaCl. Details of the ECO2N formulation may be found in Pruess (2005). The aqueous phase is the wetting phase and is denoted ‘liquid’, whereas the supercritical phase is the non-wetting phase and is denoted ‘gas’. The hysteretic formalism may be applied to other TOUGH2 equation-of-state modules that consider two fluid phases, as long as the liquid phase is the wetting phase and the gas phase is the non-wetting phase.

  3. Albuminuria and overall capillary permeability of albumin in acute altitude hypoxia

    Hansen, J M; Olsen, Niels Vidiendal; Feldt-Rasmussen, B;


    The mechanism of proteinuria at high altitude is unclear. Renal function and urinary excretion rate of albumin (Ualb) at rest and during submaximal exercise and transcapillary escape rate of 125I-labeled albumin (TERalb) were investigated in 12 normal volunteers at sea level and after rapid...... groups. Exercise did not reveal any further renal dysfunction. In both groups, high altitude increased TERalb from 4.8 to > 6.7%/h (P function and independent of effects of isradipine on filtration fraction...... and passive ascent to 4,350 m. The calcium antagonist isradipine (5 mg/day; n = 6) or placebo (n = 6) was administered to abolish hypoxia-induced rises in blood pressure. Lithium clearance and urinary excretion of beta 2-microglobulin were used to evaluate renal tubular function. High altitude increased Ualb...

  4. Hollow fiber membranes for advanced life support systems. [permeable capillaries for medical filtration

    Roebelen, G. J., Jr.; Lysaght, M. J.


    This paper describes an investigation of the practicability of utilizing hollow fiber membranes in vehicular and portable life support system applications. A preliminary screening of potential advanced life support applications resulted in the selection of five applications for feasibility study and testing. As a result of the feasibility study and testing, three applications, heat rejection, deaeration, and bacteria filtration, were chosen for breadboard development testing. Breadboard hardware has been manufactured and tested, and the physical properties of the three hollow fiber membrane assemblies applicable to use aboard future spacecraft have been characterized.

  5. Influence of local capillary trapping on containment system effectiveness

    Bryant, Steven [University Of Texas At Austin, Austin, TX (United States). Center for Petroleum and Geosystems Engineering


    , approaching a percolation threshold while non-barrier regions remain numerous. The maximum possible extent of LCT thus occurs at Pc,entrycrit near this threshold. Testing predictions of this simple algorithm against full-physics simulations of buoyancy-driven CO2 migration support the concept of critical capillary entry pressure. However, further research is needed to determine whether a single value of critical capillary entry pressure always applies and how that value can be determined a priori. Simulations of injection into high-resolution (cells 0.3 m on a side) 2D and 3D heterogeneous domains show two characteristic behaviors. At small gravity numbers (vertical flow velocity much less than horizontal flow velocity) the CO2 fills local traps as well as regions that would act as local barriers if CO2 were moving only due to buoyancy. When injection ceases, the CO2 migrates vertically to establish large saturations within local traps and residual saturation elsewhere. At large gravity numbers, the CO2 invades a smaller portion of the perforated interval. Within this smaller swept zone the local barriers are not invaded, but local traps are filled to large saturation during injection and remain during post-injection gravity-driven migration. The small gravity number behavior is expected in the region within 100 m of a vertical injection well at anticipated rates of injection for commercial GCS. Simulations of leakage scenarios (through-going region of large permeability imposed in overlying seal) indicate that LCT persists (i.e. CO2 remains held in a large fraction of the local iv traps) and the persistence is independent of injection rate during storage. Simulations of leakage for the limiting case of CO2 migrating vertically from an areally extensive emplacement in the lower portion of a reservoir showed similar strong persistence of LCT. This research has two broad

  6. Geometry of the capillary net in human hearts.

    Rakusan, K; Cicutti, N; Spatenka, J; Samánek, M


    The geometry of the coronary capillary bed in human hearts was studied using samples obtained during cardiac surgery of children operated for tetralogy of Fallot and samples from fresh normal hearts used for valve harvesting. The results revealed a similar coronary capillary density and heterogeneity of capillary spacing in samples from both groups. A double-staining method was used to distinguish between capillary segments close to the feeding arteriole (proximal capillaries) and segments distant from the arteriole (distal capillaries). In both groups of hearts, capillary segment length was consistently shorter on the venular than the arteriolar portion of the capillary. Similarly, capillary domain areas were also smaller and the resulting capillary supply unit was smaller along venular portions compared to arteriolar regions of the capillary bed. This distinctive geometry would provide advantageous geometric conditions for tissue oxygen supply. PMID:9176723

  7. The air permeability of gypsum insulating structures

    Krikunenko, V.K.; Denisova, G.F.; Omelchenko, A.S.


    The air permeability of materials made from gypsum binders used to build insulation and blast-resistant crosspieces is studied, and it is established that the materials tested provided reliable insulation due to the low air permeability factor.

  8. Permeable Pavement Research - Edison, New Jersey

    This presentation provides the background and summary of results collected at the permeable pavement parking lot monitored at the EPA facility in Edison, NJ. This parking lot is surfaced with permeable interlocking concrete pavers (PICP), pervious concrete, and porous asphalt. ...

  9. Quantifying porosity, compressibility and permeability in Shale

    Mbia, Ernest Ncha; Fabricius, Ida Lykke; Frykman, Peter;

    strain data. We found that Kozeny's modelled permeability fall in the same order of magnitude with measured permeability for shale rich in kaolinite but overestimates permeability by two to three orders of magnitudes for shale with high content of smectite. The empirical Yang and Aplin model gives good...... permeability estimate comparable to the measured one for shale rich in smectite. This is probably because Yang and Aplin model was calibrated in London clay which is rich in smectite....

  10. Effects of diagnostic ultrasound-targeted microbubble destruction on permeability of normal liver in rats.

    Yang, Dan; Tan, Kai-Bin; Gao, Yun-Hua; Liu, Hong; Yang, Wei-Xiao


    This work investigated the effect of diagnostic ultrasound-targeted microbubble destruction (UTMD) on the permeability of normal liver tissue and the safety of this technique. One hundred and four rats were divided into four groups: the control group, the microbubble-only (MB) group, the ultrasound-only (US) group, and the ultrasound-targeted microbubble destruction group (UTMD). The permeabilities of capillaries and cell membranes were determined using Evans blue and lanthanum nitrate as tracers, respectively. The amount of Evans blue was approximately fourfold higher in the UTMD group than in the control, MB-only, and US-only groups (all Precoverable and that this technique had no obvious effect on renal function. Cellular swelling was observed in liver cells in the UTMD group at 0.5 h, but this swelling was no longer apparent after 1 week. These results suggest that diagnostic ultrasound-targeted microbubble destruction can increase the capillary and cell membrane permeabilities in normal liver tissue without a significant increase in hepatic and renal toxicity. PMID:23021237

  11. "Getting the best sensitivity from on-capillary fluorescence detection in capillary electrophoresis" - A tutorial.

    Galievsky, Victor A; Stasheuski, Alexander S; Krylov, Sergey N


    Capillary electrophoresis with Laser-Induced Fluorescence (CE-LIF) detection is being applied to new analytical problems which challenge both the power of CE separation and the sensitivity of LIF detection. On-capillary LIF detection is much more practical than post-capillary detection in a sheath-flow cell. Therefore, commercial CE instruments utilize solely on-capillary CE-LIF detection with a Limit of Detection (LOD) in the nM range, while there are multiple applications of CE-LIF that require pM or lower LODs. This tutorial analyzes all aspects of on-capillary LIF detection in CE in an attempt to identify means for improving LOD of CE-LIF with on-capillary detection. We consider principles of signal enhancement and noise reduction, as well as relevant areas of fluorophore photochemistry and fluorescent microscopy. PMID:27543015


    Alina Coldea; Dorin Vlad


    This paper presents a study on the air permeability of knitted fabric manufactured using the yarns of different raw materials. The air permeability of plain pure knits wool, cotton and wool was investigated. The variation in air permeability depending on the area density, linear density, loop length and thickness of yarns.

  13. The kinetics of denitrification in permeable sediments

    Evrard, Victor; Glud, Ronnie N.; Cook, Perran L. M.


    Permeable sediments comprise the majority of shelf sediments, yet the rates of denitrification remain highly uncertain in these environments. Computational models are increasingly being used to understand the dynamics of denitrification in permeable sediments, which are complex environments to...... environment experienced in permeable sediments. In contrast to previous studies, we did not observe any significant rates of oxic denitrification....

  14. Pulmonary epithelial permeability in hyaline-membrane disease

    Neonatal hyaline-membrane disease is complicated by pulmonary edema, yet left atrial pressures are normal. Alveolar-capillary-membrane permeability may therefore be increased. To assess pulmonary epithelial permeability, we measured the pulmonary clearance and half-life of aerosolized /sup 99m/Tc-diethylenetriamine pentacetate (/sup 99m/Tc-DTPA) on 31 occasions in 15 intubated premature infants with hyaline-membrane disease. Three infants with respiratory failure due to other diseases were studied on four occasions. All studies of infants with hyaline-membrane disease that were performed in the first 72 hours of life demonstrated a biphasic clearance curve with a rapid-phase half-life of 1.6 +/- 0.6 minutes (mean +/- S.D.). As these infants recovered, the curve became monophasic with a half-life of 56.0 +/- 32.1 minutes. Two infants remained dependent on oxygen and ventilator support and had persistent biphasic curves with a rapid-phase half-life of 1.5 +/- 0.7 minutes. All infants without hyaline-membrane disease had monophasic curves with a half-life of 65.4 +/- 33.6 minutes. Using a similar technique, we observed that newborn lambs and piglets have a monophasic pulmonary clearance of /sup 99m/Tc-DTPA (114 +/- 59 minutes in lambs and 52.5 +/- 16.3 minutes in piglets). We conclude that the lungs of neonates with hyaline-membrane disease are abnormally permeable to small solutes and that this abnormality persists in infants with subsequent chronic lung disease

  15. Sanding process and permeability change

    Xue, S. [Petroleum Univ., Beijing (China); Yuan, Y.


    Sand production is a major problem in the petroleum industry, particularly with operators aggressive production schedules. Sand production occurs when the well fluid under high pumping rate dislodges part of the formation solids causing a continuous flux of formation solids. It increases completion costs, plus it erodes casings, pipes and pumps. However, sand production can also effectively increase well productivity in heavy oil and light oil reservoirs.The challenge in understanding the sanding process lies in developing a mathematical model which can predict the amount of sand production. A quantitative model would allow engineers to understand the unique phenomena and evaluate the impact of sand production on reservoir enhancement. Measures could then be taken to reduce unnecessary costs during field operations. In order to develop such a model, the complicated sanding process equations was divided into a fluid flow and sand transport equation, and into a porous solid matrix deforming and stress concentration or failure function equation. The two types of sand production mechanisms that were presented in this paper were the production of coarse sands under mechanical failure and the production of fine sands under hydro-dynamical erosion. The behaviour of sandstone deformation was examined using the Drucker-Prager constitutive law with cap hardening criterion. The governing equation system was solved using the finite element method. The model was validated using field data for sand production and permeability change obtained from 10 wells in Gudong, China. It was shown that permeability can be modified at any time during the sanding process of a well. Permeability can be reduced by up to 60 per cent of the initial level under depletion production. It was determined that the best way to control permeability decline is to balance the pore pressure. 9 refs., 1 tab., 7 figs.

  16. Uniaxial creep as a control on mercury intrusion capillary pressure in consolidating rock salt

    Dewers, Thomas [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Heath, Jason E. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Leigh, Christi D. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)


    The nature of geologic disposal of nuclear waste in salt formations requires validated and verified two - phase flow models of transport of brine and gas through intact, damaged, and consolidating crushed salt. Such models exist in oth er realms of subsurface engineering for other lithologic classes (oil and gas, carbon sequestration etc. for clastics and carbonates) but have never been experimentally validated and parameterized for salt repository scenarios or performance assessment. Mo dels for waste release scenarios in salt back - fill require phenomenological expressions for capillary pressure and relative permeability that are expected to change with degree of consolidation, and require experimental measurement to parameterize and vali date. This report describes a preliminary assessment of the influence of consolidation (i.e. volume strain or porosity) on capillary entry pressure in two phase systems using mercury injection capillary pressure (MICP). This is to both determine the potent ial usefulness of the mercury intrusion porosimetry method, but also to enable a better experimental design for these tests. Salt consolidation experiments are performed using novel titanium oedometers, or uniaxial compression cells often used in soil mech anics, using sieved run - of - mine salt from the Waste Isolation Pilot Plant (WIPP) as starting material. Twelve tests are performed with various starting amounts of brine pore saturation, with axial stresses up to 6.2 MPa (%7E900 psi) and temperatures to 90 o C. This corresponds to UFD Work Package 15SN08180211 milestone "FY:15 Transport Properties of Run - of - Mine Salt Backfill - Unconsolidated to Consolidated". Samples exposed to uniaxial compression undergo time - dependent consolidation, or creep, to various deg rees. Creep volume strain - time relations obey simple log - time behavior through the range of porosities (%7E50 to 2% as measured); creep strain rate increases with temperature and applied stress as

  17. Capillary electrochromatography using fibers as stationary phases.

    Jinno, K; Watanabe, H; Saito, Y; Takeichi, T


    Fiber-packed capillary columns have been evaluated in chromatographic performance in capillary electrochromatography (CEC). The change of electroosmotic flow (EOF) velocity and selectivity using different kinds of fiber materials was examined. Although the EOF velocity among the different fiber packed columns was almost the same, retention of parabens was larger on the Kevlar-packed column than on the Zylon-packed one, and was larger on the as-span-type fiber-packed column than on the high-modulus-type packed one. Using 200 microm ID x 5 cm Kevlar packed column combined with a 100 microm ID x 20 cm precolumn capillary and a 530 microm ID x 45 cm postcolumn capillary, the separation of three parabens within 30 s was achieved. Other compounds were also separated in a few minutes by the fiber-packed CEC method. PMID:11669512

  18. Uptake of water droplets by nonwetting capillaries

    Willmott, Geoff R; Hendy, Shaun C


    We present direct experimental evidence that water droplets can spontaneously penetrate non-wetting capillaries, driven by the action of Laplace pressure due to high droplet curvature. Using high-speed optical imaging, microcapillaries of radius 50 to 150 micron, and water microdroplets of average radius between 100 and 1900 micron, we demonstrate that there is a critical droplet radius below which water droplets can be taken up by hydrophobised glass and polytetrafluoroethylene (PTFE) capillaries. The rate of capillary uptake is shown to depend strongly on droplet size, with smaller droplets being absorbed more quickly. Droplet size is also shown to influence meniscus motion in a pre-filled non-wetting capillary, and quantitative measurements of this effect result in a derived water-PTFE static contact angle between 96 degrees and 114 degrees. Our measurements confirm recent theoretical predictions and simulations for metal nanodroplets penetrating carbon nanotubes (CNTs). The results are relevant to a wide ...

  19. Capillary Electrophoresis coupled with Automated Fraction Collection

    Huge, Bonnie Jaskowski; Flaherty, Ryan; Dada, Oluwatosin O.; Dovichi, Norman J.


    A fraction collector based on a drop-on-demand ink-jet printer was developed to interface capillary zone electrophoresis with a 96 well microtiter plate. We first evaluated the performance of the collector by using capillary zone electrophoresis to analyze a 1 mM solution of tetramethylrhodamine; a fluorescent microtiter plate reader was then used to detect the analyte and characterize fraction carryover between wells. Relative standard deviation in peak height was 20% and the relative standa...

  20. The capillary electrophoresis of the influenza viruses

    Horká, Marie; Kubesová, Anna; Kubíček, O.; Kubíčková, Z.; Rosenbergová, K.; Šlais, Karel

    Tallinn: Tallinn University of Technology, 2009 - (Borissova, M.; Vaher, M.). s. 93 ISBN 978-9985-59-930-3. [Nordic Separation Science Society (NoSSS) International Conference /5./. 26.08.2009-29.08.2009, Tallinn] R&D Projects: GA AV ČR IAAX00310701 Institutional research plan: CEZ:AV0Z40310501 Keywords : capillary isoelectric focusing * capillary electrophoresis * influenza swine and equine viruses Subject RIV: CB - Analytical Chemistry, Separation

  1. Selectivity and detection in capillary electrophoresis

    Khaled, Maha Yehia


    This work is a contribution to the minimization of some of the selectivity and detection limitations in capillary electrophoresis. A more practical design of an electrochemical detector is introduced with simultaneous on-line UV detection (1), for the selective detection of a number of pungent and neurological compounds, the piperines and the capsacinoids. Commercially available microelectrodes together with large 25 μm id fused silica capillary columns are used for the fir...

  2. Aspects of tensor permeability in reservoir simulation

    Rogers, C.F.


    A number of simulation grids relevant to reservoir engineering practice are studied. The impact of neglecting correct local flux and pressure continuity at the grid cell interfaces is assessed. It is shown that the correct local interface conditions with increased discretisation support lead to improved solutions on non-orthogonal grids with the generation of a full permeability tensor. A full tensor permeability arises even when the permeability is non-isotropic on orthogonal grids. The approach described efficiently includes the permeability tensor contributions from the geometric grid structure, but also implies the importance of modelling the full permeability tensor pressure equation in the reservoir simulation up-scaling process. (orig.)

  3. On the permeability of fractal tube bundles

    Zinovik, I


    The permeability of a porous medium is strongly affected by its local geometry and connectivity, the size distribution of the solid inclusions and the pores available for flow. Since direct measurements of the permeability are time consuming and require experiments that are not always possible, the reliable theoretical assessment of the permeability based on the medium structural characteristics alone is of importance. When the porosity approaches unity, the permeability-porosity relationships represented by the Kozeny-Carman equations and Archie's law predict that permeability tends to infinity and thus they yield unrealistic results if specific area of the porous media does not tend to zero. The goal of this paper is an evaluation of the relationships between porosity and permeability for a set of fractal models with porosity approaching unity and a finite permeability. It is shown that the two-dimensional foams generated by finite iterations of the corresponding geometric fractals can be used to model poro...

  4. Ammonia and urea permeability of mammalian aquaporins

    Litman, Thomas; Søgaard, Rikke; Zeuthen, Thomas


    /arginine region, and an exclusively water-permeable aquaporin can be transformed into an ammonia-permeable aquaporin by single point mutations in this region. The ammonia-permeable aquaporins fall into two groups: those that are permeable (AQP3, 7, 9, 10) and those that are impermeable (AQP8) to glycerol. The two......The human aquaporins,AQP3,AQP7, AQP8,AQP9, and possibly AQP10, are permeable to ammonia, and AQP7, AQP9, and possibly AQP3, are permeable to urea. In humans, these aquaporins supplement the ammonia transport of the Rhesus (Rh) proteins and the urea transporters (UTs). The mechanism by which...... significant at alkaline pH. It is debated whether the H(+) ion passes via the aquaporin or by some external route; the investigation of this problem requires the aquaporin-expressing cell to be voltage-clamped. The ammonia-permeable aquaporins differ from other aquaporins by having a less restrictive aromatic...

  5. Capillary fracture of soft gels.

    Bostwick, Joshua B; Daniels, Karen E


    A liquid droplet resting on a soft gel substrate can deform that substrate to the point of material failure, whereby fractures develop on the gel surface that propagate outwards from the contact line in a starburst pattern. In this paper, we characterize (i) the initiation process, in which the number of arms in the starburst is controlled by the ratio of the surface tension contrast to the gel's elastic modulus, and (ii) the propagation dynamics showing that once fractures are initiated they propagate with a universal power law L[proportional]t(3/4). We develop a model for crack initiation by treating the gel as a linear elastic solid and computing the deformations within the substrate from the liquid-solid wetting forces. The elastic solution shows that both the location and the magnitude of the wetting forces are critical in providing a quantitative prediction for the number of fractures and, hence, an interpretation of the initiation of capillary fractures. This solution also reveals that the depth of the gel is an important factor in the fracture process, as it can help mitigate large surface tractions; this finding is confirmed with experiments. We then develop a model for crack propagation by considering the transport of an inviscid fluid into the fracture tip of an incompressible material and find that a simple energy-conservation argument can explain the observed material-independent power law. We compare predictions for both linear elastic and neo-Hookean solids, finding that the latter better explains the observed exponent. PMID:24229192

  6. Use of capillary electrophoresis and indirect detection to quantitate in-capillary enzyme-catalyzed microreactions.

    Zhang, Y; el-Maghrabi, M R; Gomez, F A


    The use of capillary electrophoresis and indirect detection to quantify reaction products of in-capillary enzyme-catalyzed microreactions is described. Migrating in a capillary under conditions of electrophoresis, plugs of enzyme and substrate are injected and allowed to react. Capillary electrophoresis is subsequently used to measure the extent of reaction. This technique is demonstrated using two model systems: the conversion of fructose-1,6-bisphosphate to dihydroxyacetone phosphate and glyceraldehyde-3-phosphate by fructose-biphosphate aldolase (ALD, EC, and the conversion of fructose-1,6-bisphosphate to fructose-6-phosphate by fructose-1,6-bisphospatase (FBPase, EC These procedures expand the use of the capillary as a microreactor and offer a new approach to analyzing enzyme-mediated reactions. PMID:10892022

  7. A Novel Polybrene/Chondroitin Sulfate C Double Coated Capillary and Its Application in Capillary Electrophoresis

    DU,Ying-Xiang(杜迎翔); HONDA,Susumu; TAGA,Atsushi; LIU,Wen-Ying(刘文英); SUZUKI,Shigeo


    A new capillary coated by double polymer, polybrene/chondroitin sulfate C (P/CC), was developed using a simple procedure. The P/CC double coated capillary showed long lifetime,strong chemical stability and good reproducibility. It endured during more than 100 replicated analyses and was also tolerant to HCl (1 mol/L), NaOH (0.01 mol/L), CH3OH and CH3CN. The P/CC double coated capillary can be applied to basic drug analyses. The adsorption of basic drugs to the capillary wall was suppressed and the peak tailing greatly decreased. The use of the P/CC double coated capillary allowed excelent separation of the enantiomers of some basic drugs by using chondroitin sulfate C as the chiral selector, ami the peak symmetry of basic drugs was further improved under these conditions.

  8. Nanoparticle-based capillary electroseparation of proteins in polymer capillaries under physiological conditions

    Nilsson, C.; Harwigsson, I.; Becker, K.;


    of nanoparticles, i.e. in CE mode, the protein samples adsorbed completely to the capillary walls and could not be recovered. In contrast, nanoparticle-based capillary electroseparation resolved green fluorescent protein from several of its impurities within I min. Furthermore, a mixture of native green...... fluorescent protein and two of its single-amino-acid-substituted variants was separated within 2.5 min with efficiencies of 400 000 plates/m. The nanoparticles prevent adsorption by introducing a large interacting surface and by obstructing the attachment of the protein to the capillary wall. A one......Totally porous lipid-based liquid crystalline nanoparticles were used as pseudostationary phase for capillary electroseparation with LIF detection of proteins at physiological conditions using unmodified cyclic olefin copolymer capillaries (Topas (R), 6.7 cm effective length). In the absence...

  9. Capillary-Tube Model and Experiment of Multiphase Flow in Capillary Fringes

    武晓峰; 唐杰; 吕贤弼


    Contamination of soil and groundwater by organic substances is causing more and more problems worldwide. Analysis of the movement and distribution of nonaqueous phase liquids (NAPLs) in subsurface domain is critical for contaminant remediation. Two-dimensional experiments were conducted in a transparent plexiglass trough (105.0 cm×70.0 cm×1.5 cm) to simulate the release and redistribution of gasoline and kerosene in porous media. The results show that before the contaminant distribution reaches equilibrium, the movement of light NAPLs (LNAPLs) can be divided into four sub-stages. After the contaminant front reaches the upper boundary of the capillary fringe, contaminant movement along the upper boundary of the capillary fringe is the primary transport process. Most of the contaminants then move into the capillary fringe except for the residual part. One-dimensional and two-dimensional capillary tube models were developed to analyze the movement of LNAPLs in the capillary fringe.

  10. Flow Rate- and Fracture Property Dependence of Fracture-Matrix Ensemble Relative Permeability

    Matthai, S. K.; Lang, P.; Bazrafkan, S.


    The grid-block scale ensemble relative permeability, kri of fractured porous rock with appreciable matrix permeability is of decisive interest to reservoir simulation and the prediction of production, injector-producer water breakthrough, and ultimate recovery. While the dynamic behaviour of naturally fractured reservoirs (NFR) already provides many clues about (pseudo) kri on the inter-well length scale, such data are difficult to interpret because, in the subsurface, the exact fracture geometry is unknown. Here we present numerical simulation results from discrete fracture and matrix (DFM) unstructured grid hybrid FEM-FVM simulation models, predicting the shape of fracture-matrix kri curves. In contrast to our earlier work, we also simulate capillary fracture matrix transfer (CFMT) and without relying the frequently made simplifying assumption that fracture saturation reflects fracture-matrix capillary pressure equilibrium. We also employ a novel discretization of saturation which permits jump discontinuities to develop across the fracture-matrix interface. This increased physical realism permits - for the first time - to test our earlier semi-analytical model of the flow rate dependence of relative permeability, ensuing from CFMT. The sensitivity analysis presented here constrains CMFT-related flow rate dependence of kri and illustrates how it manifests itself in two geometries of layer-restricted well-developed fracture patterns mapped in the field. We have also investigated the dependence of kri on fracture aperture as computed using discrete element analysis for plausible states of in situ stress. Our results indicate that fracture-matrix ensemble relative permeability can be matched with a new semi-analytic model taking into account the fracture-matrix flux ratio, the wetted fracture-matrix interface area as a function of saturation and the breakthrough saturation. However, we also detect a scale dependence of kri requiring a more elaborate treatment.

  11. A new method of building permeability model in low-permeability reservoir numerical simulation

    Lei Su; Lin-Song Cheng; Yong-Chao Xue


    Aiming at solving the problem that big differ-ence exists between logging permeability and true permeability of micro-fractured low-permeability sand reservoir, this paper puts forward a new method to revise logging per-meability by using primiparity data of oil field. This method has been successfully applied to revise logging permeability of micro-fractured low-permeability sand reservoir in Baiyushan area of Jing’An oil field, which shows that the method is reliable because the geological ...

  12. Steam-water relative permeability

    Ambusso, W.; Satik, C.; Home, R.N. [Stanford Univ., CA (United States)


    A set of relative permeability relations for simultaneous flow of steam and water in porous media have been measured in steady state experiments conducted under the conditions that eliminate most errors associated with saturation and pressure measurements. These relations show that the relative permeabilities for steam-water flow in porous media vary approximately linearly with saturation. This departure from the nitrogen/water behavior indicates that there are fundamental differences between steam/water and nitrogen/water flows. The saturations in these experiments were measured by using a high resolution X-ray computer tomography (CT) scanner. In addition the pressure gradients were obtained from the measurements of liquid phase pressure over the portions with flat saturation profiles. These two aspects constitute a major improvement in the experimental method compared to those used in the past. Comparison of the saturation profiles measured by the X-ray CT scanner during the experiments shows a good agreement with those predicted by numerical simulations. To obtain results that are applicable to general flow of steam and water in porous media similar experiments will be conducted at higher temperature and with porous rocks of different wetting characteristics and porosity distribution.

  13. The capillary hysteresis model HYSTR: User's guide

    The potential disposal of nuclear waste in the unsaturated zone at Yucca Mountain, Nevada, has generated increased interest in the study of fluid flow through unsaturated media. In the near future, large-scale field tests will be conducted at the Yucca Mountain site, and work is now being done to design and analyze these tests. As part of these efforts a capillary hysteresis model has been developed. A computer program to calculate the hysteretic relationship between capillary pressure φ and liquid saturation (S1) has been written that is designed to be easily incorporated into any numerical unsaturated flow simulator that computes capillary pressure as a function of liquid saturation. This report gives a detailed description of the model along with information on how it can be interfaced with a transport code. Although the model was developed specifically for calculations related to nuclear waste disposal, it should be applicable to any capillary hysteresis problem for which the secondary and higher order scanning curves can be approximated from the first order scanning curves. HYSTR is a set of subroutines to calculate capillary pressure for a given liquid saturation under hysteretic conditions

  14. Synthetic Capillaries to Control Microscopic Blood Flow

    Sarveswaran, K.; Kurz, V.; Dong, Z.; Tanaka, T.; Penny, S.; Timp, G.


    Capillaries pervade human physiology. The mean intercapillary distance is only about 100 μm in human tissue, which indicates the extent of nutrient diffusion. In engineered tissue the lack of capillaries, along with the associated perfusion, is problematic because it leads to hypoxic stress and necrosis. However, a capillary is not easy to engineer due to its complex cytoarchitecture. Here, it is shown that it is possible to create in vitro, in about 30 min, a tubular microenvironment with an elastic modulus and porosity consistent with human tissue that functionally mimicks a bona fide capillary using “live cell lithography”(LCL) to control the type and position of cells on a composite hydrogel scaffold. Furthermore, it is established that these constructs support the forces associated with blood flow, and produce nutrient gradients similar to those measured in vivo. With LCL, capillaries can be constructed with single cell precision—no other method for tissue engineering offers such precision. Since the time required for assembly scales with the number of cells, this method is likely to be adapted first to create minimal functional units of human tissue that constitute organs, consisting of a heterogeneous population of 100-1000 cells, organized hierarchically to express a predictable function.

  15. EUV radiation from nitrogen capillary discharge

    Frolov, Oleksandr; Kolacek, Karel; Schmidt, Jiri; Straus, Jaroslav


    In the last decade EUV sources attract interest from researchers over the world. One of the main motivations is EUV lithography, which could lead to further miniaturization in electronics. Nitrogen recombination laser at wavelength of 13.4 nm based on capillary discharge Z-pinch configuration could be used in experiments with testing of resolution of photoresist for EUV lithography (close to wavelength of 13.5 nm Si/Mo multilayer mirrors have a high reflectivity at normal incidence angles). In this work, pinching of nitrogen-filled capillary discharge is studied for the development of EUV laser, which is based on recombination pumping scheme. The goal of this study is achieving the required plasma conditions using a capillary discharge Z-pinch apparatus. In experiments with nitrogen, the capillary length was shortened from 232 mm to 90 mm and current quarter-period was changed from 60 ns to 50 ns in contrast with early experiments with Ne-like argon laser. EUV radiation from capillary discharge was registered by X-ray vacuum diode for different pressure, amplitude and duration of pre-pulse and charging voltage of the Marx generator.

  16. Effect of temperature on sandstone permeability

    Rosenbrand, Esther; Kjøller, Claus

    Hot water injection in geothermal sandstone aquifers is considered for seasonal energy storage in Denmark. However, an increase in the aquifer temperature might reduce permeability, and thereby increase production costs. An understanding of the factors that control permeability is required in order...... to address the effects of temperature on permeability. Therefore, different aspects of sandstone permeability are investigated in this research project. Data from a range of sources including: published literature; a database containing over 120 tight gas sandstone samples; new flow...... permeability to sandstone texture. The simple physically based Kozeny (1927) equation, relates permeability to porosity and specific surface per pore volume, or equivalent pore size, for a homogeneous porous medium with a uniform pore size. As pore sizes in sandstones can range from nanometres to micrometres...

  17. Modelling of water permeability in cementitious materials

    Guang, Ye; Lura, Pietro; van Breugel, K.


    This paper presents a network model to predict the permeability of cement paste from a numerical simulation of its microstructure. Based on a linked list pore network structure, the effective hydraulic conductivity is estimated and the fluid flow is calculated according to the Hagen-Poiseuille law....... The pressure gradient at all nodes is calculated with the Gauss elimination method and the absolute permeability of the pore network is calculated directly from Darcy's law. Finally, the permeability model is validated by comparison with direct water permeability measurements. According to this model......, the predicted permeability of hydrating cement pastes is extremely sensitive to the particle size distribution of the cement and especially to the minimum size of the cement particles. Both in simulations and experiments, the permeability of cement pastes is mainly determined by the critical diameter...

  18. The Role of Capillary Barrier in Reducing Moisture Content on Waste Packages

    Assessment of the performance of engineered capillary barriers at the potential Yucca Mountain nuclear waste repository site, in which 1.67-m-diameter waste packages are to be emplaced in 5-m-diameter tunnels according to current design, brings up aspects not commonly considered in more typical applications of capillary barriers (e.g., near-surface landfills). Engineered capillary barriers typically consist of two layers of granular materials with a sloping interface, in which the contrast in capillarity between the layers keeps infiltrating water in the upper layer. One issue is the effect of thermohydrologic processes that would occur at elevated repository temperatures (and temperature gradients). For example, backfill materials may be altered from that of the as-placed material by the hydrothermal regime imposed by the emplacement of waste in the repository, changing hydrologic properties in a way that degrades the performance of the barrier. A reduction of permeability in the upper layer might diminish the capacity of the upper layer to divert incoming seepage or to cause a ''vapor lid'' whereby buoyant vapor flow would be trapped, then condense and drain onto waste packages. Other concerns are the result of highly spatially and temporally variable seepage distribution and the very limited spatial scale available for flow attenuation and diversion

  19. Water vapour permeability of clay bricks

    Dondi, M.; Principi, P.; Raimondo, M.; Zanarini, G.


    The water vapour permeability of clay bricks has been experimentally measured in order to draw a representative outline of industrial products without pore-forming additives. The correlations between water vapour permeability and the main compositional and microstructural parameters of both bricks and clay bodies have been investigated. A statistical model was set up in order to predict with reasonable precision and reliability, the water vapour permeability on the basis of open porosity, bul...

  20. Flow unit modeling and fine-scale predicted permeability validation in Atokan sandstones: Norcan East Kansas

    Bhattacharya, S.; Byrnes, A.P.; Watney, W.L.; Doveton, J.H.


    Characterizing the reservoir interval into flow units is an effective way to subdivide the net-pay zone into layers for reservoir simulation. Commonly used flow unit identification techniques require a reliable estimate of permeability in the net pay on a foot-by-foot basis. Most of the wells do not have cores, and the literature is replete with different kinds of correlations, transforms, and prediction methods for profiling permeability in pay. However, for robust flow unit determination, predicted permeability at noncored wells requires validation and, if necessary, refinement. This study outlines the use o f a spreadsheet-based permeability validation technique to characterize flow units in wells from the Norcan East field, Clark County, Kansas, that produce from Atokan aged fine- to very fine-grained quartzarenite sandstones interpreted to have been deposited in brackish-water, tidally dominated restricted tidal-flat, tidal-channel, tidal-bar, and estuary bay environments within a small incised-valley-fill system. The methodology outlined enables the identification of fieldwide free-water level and validates and refines predicted permeability at 0.5-ft (0.15-m) intervals by iteratively reconciling differences in water saturation calculated from wire-line log and a capillary-pressure formulation that models fine- to very fine-grained sandstone with diagenetic clay and silt or shale laminae. The effectiveness of this methodology was confirmed by successfully matching primary and secondary production histories using a flow unit-based reservoir model of the Norcan East field without permeability modifications. The methodologies discussed should prove useful for robust flow unit characterization of different kinds of reservoirs. Copyright ?? 2008. The American Association of Petroleum Geologists. All rights reserved.

  1. Literature review and recommendation of methods for measuring relative permeability of anhydrite from the Salado Formation at the Waste Isolation Pilot Plant

    This report documents a literature review of methods for measuring relative permeability as applied to low permeability anhydrite rock samples from the Salado Formation. About one hundred papers were reviewed, and four methods were identified as promising techniques for measuring the relative permeability of the Salado anhydrite: (1) the unsteady-state high-rate method, (2) the unsteady-state stationary-liquid method, (3) the unsteady-state centrifuge method, and (4) the unsteady-state low-rate method. Except for the centrifuge method, all have been used for low permeability rocks. The unsteady-state high-rate method is preferred for measuring relative permeability of Salado anhydrite, and the unsteady-state stationary-liquid method could be well suited for measuring gas relative permeability of Salado anhydrite. The unsteady-state low-rate method, which combines capillary pressure effects with relative permeability concepts may also prove effective. Likewise, the unsteady-state centrifuge method may be an efficient means for measuring brine relative permeability for Salado anhydrite, especially at high gas saturations

  2. Permeability Tests on Eastern Scheldt Sand

    Jakobsen, Kim Parsberg

    The flow through porous media plays an important role in various engineering disciplines, as for example in ground water hydrology and soil mechanics. In the present study the permeability is determined for a fine, saturated sand. As the flow through a porous media strongly depends on the...... characteristics of the soil matrix, the permeability is determined for different void ratios. All tests are performed on reconstituted specimens of Eastern Scheldt Sand. The permeability is determined by use of a falling head apparatus. Finally the test results are briefly summarised and a relationship between...... void ratio and permeability is established....

  3. Permeability of Electrospun Superhydrophobic Nanofiber Mats

    Sarfaraz U. Patel


    Full Text Available This paper discusses the fabrication and characterization of electrospun nanofiber mats made up of poly(4-methyl-1-pentene polymer. The polymer was electrospun in different weight concentrations. The mats were characterized by their basis weight, fiber diameter distribution, contact angles, contact angle hysteresis, and air permeability. All of the electrospun nonwoven fiber mats had water contact angles greater than 150 degrees making them superhydrophobic. The permeabilities of the mats were empirically fitted to the mat basis weight by a linear relation. The experimentally measured air permeabilities were significantly larger than the permeabilities predicted by the Kuwabara model for fibrous media.

  4. Novel absorption detection techniques for capillary electrophoresis

    Xue, Y.


    Capillary electrophoresis (CE) has emerged as one of the most versatile separation methods. However, efficient separation is not sufficient unless coupled to adequate detection. The narrow inner diameter (I.D.) of the capillary column raises a big challenge to detection methods. For UV-vis absorption detection, the concentration sensitivity is only at the {mu}M level. Most commercial CE instruments are equipped with incoherent UV-vis lamps. Low-brightness, instability and inefficient coupling of the light source with the capillary limit the further improvement of UV-vis absorption detection in CE. The goals of this research have been to show the utility of laser-based absorption detection. The approaches involve: on-column double-beam laser absorption detection and its application to the detection of small ions and proteins, and absorption detection with the bubble-shaped flow cell.

  5. Capillary filling in closed end nanochannels.

    Phan, Vinh Nguyen; Nguyen, Nam-Trung; Yang, Chun; Joseph, Pierre; Djeghlaf, Lyes; Bourrier, David; Gue, Anne-Marie


    We investigated the interactions between liquid, gas, and solid phases in the capillary filling process of closed-end nanochannels. This paper presents theoretical models without and with absorption and diffusion of gas molecules in the liquid. Capillary filling experiments were carried out in closed-end silicon nanochannels with different lengths. The theoretical and measured characteristics of filling length versus time are compared. The results show that the filling process consists of two stages. The first stage resembles the capillary filling process in an open-end nanochannel. However, a remarkable discrepancy between the experimental results and the theory without gas absorption is observed in the second stage. A closer investigation of the second stage reveals that the dissolution of gas in the liquid is important and can be explained by the model with gas absorption and diffusion. PMID:20695566

  6. Capillary interactions in nano-particle suspensions

    We have investigated the structures formed by colloidal particles suspended in solvents at volume fractions below 10% and interacting through capillary bridges. Such systems resemble colloidal gas of sticky nano-spheres that form pearl-necklace like chains that, in turn, induce strong viscoelasticity due to the formation of 3-D fractal network. The capillary force dominates the electrostatic and Van der Waals forces in solutions and can bridge multiple particles depending of the volume of the capillary bridge. We have investigated the morphology of the structures formed at different fractions of the bridging fluid. Small-angle neutron scattering (SANS) is used to study nanoparticles with an average diameter of 10 nm in polar and non-polar organic solvents at ambient temperatures. SANS intensity as a function of the scattering vector is analyzed as a product of a form factor, that depends on the particle shape, and a structure factor, that characterizes the interparticle inter reactions. The interaction of particles in polar solvents is considered to be through electrostatic repulsion and the data is successfully fitted by Hayter-Penfold mean spherical approximation (HPMSA). Computer simulations of a pearl necklace-like chain of spheres is conducted to explain the structure factor when capillary bridges are present. Alternatively, we have analyzed the slope of the intensity at low scattering vector in a double logarithmic plot to determine the dimension of the fractal structures formed by the particles at different volume fraction of the bridging fluid. We have also studied the properties of the capillary bridge between a pair of particles. The significance of this study is to explore the possibility of using capillary force as a tool to engineer new colloidal structures and materials in solutions and to optimize their viscoelastic properties. (author)

  7. Capillary Rise of Liquids in Nanopores

    Huber, Patrick; Kityk, Andriy V


    We present measurements on the spontaneous imbibition (capillary rise) of water, a linear hydrocarbon (n-C16H34) and a liquid crystal (8OCB) into the pore space of monolithic, nanoporous Vycor glass (mean pore radius 5 nm). Measurements on the mass uptake of the porous hosts as a function of time, m(t), are in good agreement with the Lucas-Washburn square root of time prediction, typical of imbibition of liquids into porous hosts. The relative capillary rise velocities scale as expected from the bulk fluid parameters.

  8. A lymph nodal capillary-cavernous hemangioma.

    Dellachà, A; Fulcheri, E; Campisi, C


    A capillary-cavernous hemangioma in an obturator lymph node was found incidentally in a 64 year-old woman who had undergone unilateral salpingo-oophorectomy and lymphadenectomy for an ovarian neoplasm. Vascular tumors of lymph nodes are briefly reviewed including eight previously described nodal capillary-cavernous hemangiomas. The association with other splanchnic hemangiomas is pointed out and the likelihood that the lesion is a hamartoma rather than a true neoplasm is addressed. Despite its rarity, this entity needs to be recognized by lymphologists who image lymph nodes by lymphangiography as well as by lymph nodal pathologists. PMID:10494525

  9. Intracerebral Capillary Hemangioma: A Case Report

    Youn, In Young; Kim, Jae Kyun; Byun, Jun Soo [Dept. of Radiology, Chung Ang University Medical Center, Chung Ang University College of Medicine, Seoul (Korea, Republic of); Park, Eon Sub [Dept. of Radiology, Chung Ang University Medical Center, Chung Ang University College of Medicine, Seoul (Korea, Republic of)


    Intracerebral capillary hemangiomas are very rare benign vascular tumors that mostly occur during infancy. We described a 69-year-old man with generalized tonic-clonic seizures who was diagnosed with an intracranial mass. Multidetector computed tomography, magnetic resonance imaging and digital subtraction angiography studies were performed for evaluation of brain, and there was a well-enhancing mass found in the right temporal lobe without a definite feeding vessel. The patient underwent surgery and the pathologic examination demonstrated marked proliferation of small vessels with a lobular pattern in the brain parenchyma, which was confirmed to be capillary hemangioma.

  10. Microfluidic chip-capillary electrophoresis devices

    Fung, Ying Sing; Du, Fuying; Guo, Wenpeng; Ma, Tongmei; Nie, Zhou; Sun, Hui; Wu, Ruige; Zhao, Wenfeng


    Capillary electrophoresis (CE) and microfluidic chip (MC) devices are relatively mature technologies, but this book demonstrates how they can be integrated into a single, revolutionary device that can provide on-site analysis of samples when laboratory services are unavailable. By introducing the combination of CE and MC technology, Microfluidic Chip-Capillary Electrophoresis Devices broadens the scope of chemical analysis, particularly in the biomedical, food, and environmental sciences.The book gives an overview of the development of MC and CE technology as well as technology that now allows


    A. S. Markova


    Full Text Available The paper describes a clinical case of testicular capillary hemangioma in a 24-year-old man undergone a partial resection of the testis with the intraoperative morphological examination. Testicular capillary hemangioma is a rare benign tumor of a vascular origin, which can be similar to malignant testicular tumors on the clinical presentation, as well as on the imaging methods, in particular to seminoma. The intraoperative histological study can assist in avoiding organ-removing surgical interventions in diagnostically ambiguous cases if a benign testicular tumor is diagnosed.

  12. Quantification of nucleotides by ICPMS: coupling of ICPMS with capillary electrophoresis or capillary HPLC

    Full text: Quantification of nucleotides in small volumes of biological samples has eagerly been demanded. A method using ICPMS coupled with capillary electrophoresis or capillary liquid chromatography is reported. A new interface system, which consists of a double tube nebulizer inserted with a fused silica capillary tube and a cylinder mini-chamber with a sheath gas inlet, was designed. Moreover, the surface conditions of the sampling and skimmer cones, and the introduction of H2 gas into the plasma were found to significantly improve the signal/background ratio for phosphorus determination at m/z 31. (author)

  13. Permeability Calculation in a Fracture Network - 12197

    Laminar flow of a viscous fluid in the pore space of a saturated fractured rock medium is considered to calculate the effective permeability of the medium. The effective permeability is determined from the flow field which is calculated numerically by using the finite element method. The computation of permeability components is carried out with a few different discretizations for a number of fracture arrangements. Various features such as flow field in the fracture channels, the convergence of permeability, and the variation of permeability among different fracture networks are discussed. The longitudinal permeability in general appears greater than the transverse ones. The former shows minor variations with fracture arrangement whereas the latter appears to be more sensitive to the arrangement. From the calculations of the permeability in a rock medium with a fracture network (two parallel fractures aligned in the direction of 45-deg counterclockwise from the horizontal and two connecting fractures(narrowing, parallel and widening) the following conclusions are drawn. 1. The permeability of fractured medium not only depends on the primary orientation of the main fractures but also is noticeably influenced by the connecting fractures in the medium. 2. The transverse permeability (the permeability in the direction normal to the direction of the externally imposed macro-scale pressure gradient) is only a fraction of the longitudinal one, but is sensitive to the arrangement of the connecting fractures. 3. It is important to figure out the pattern of the fractures that connect (or cross) the main fractures for reliable calculation of the transverse permeability. (authors)

  14. Viscosity measurement in the capillary tube viscometer under unsteady flow

    The objective of the present study is to develop a new device that the viscous characteristics of fluids are determined by applying the unsteady flow concept to the traditional capillary tube viscometer. The capillary tube viscometer consists of a small cylindrical reservoir, capillary tube, a load cell system that measures the mass flow rate, interfaces, and computer. Due to the small size of the reservoir the height of liquid in the reservoir decreases as soon as the liquid in the reservoir drains out through the capillary and the mass flow rate in the capillary decreases as the hydrostatic pressure in the reservoir decreases resulting in a decrease of the shear rate in the capillary tube. The instantaneous shear rate and driving force in the capillary tube are determined by measuring the mass flow rate through the capillary, and the fluid viscosity is determined from the measured flow rate and the driving force

  15. A Rare Association of Trigeminal Autonomic Cephalgia: Pontine Capillary Telangiectasia

    Gocmen, Rahsan; Kurt, Erdal; Arslan, Sabina; Unal-Cevik, Isin; Karli Oguz, Kader; Tezer, F Irsel


    This report describes a case of pontine capillary telangiectasia in a 43-year-old woman with a clinical diagnosis of trigeminal autonomic cephalgia. The possible association with pontine capillary telangiectasia and trigeminal autonomic cephalgia is discussed.

  16. Method to quantify the notional permeability

    Verhagen, H.J.; Jumelet, D.; Vilaplana Domingo, A.; Van Broekhoven, P.


    In de Van der Meer formulas for armour stability the Notional Permeability is used as a parameter. Unfortunately the physical basis of this parameter is weak. It is therefore suggested to use a relation between the Notional Permeability P and the reduction of wave run-up due to infiltration into the

  17. Accurate determination of characteristic relative permeability curves

    Krause, Michael H.; Benson, Sally M.


    A recently developed technique to accurately characterize sub-core scale heterogeneity is applied to investigate the factors responsible for flowrate-dependent effective relative permeability curves measured on core samples in the laboratory. The dependency of laboratory measured relative permeability on flowrate has long been both supported and challenged by a number of investigators. Studies have shown that this apparent flowrate dependency is a result of both sub-core scale heterogeneity and outlet boundary effects. However this has only been demonstrated numerically for highly simplified models of porous media. In this paper, flowrate dependency of effective relative permeability is demonstrated using two rock cores, a Berea Sandstone and a heterogeneous sandstone from the Otway Basin Pilot Project in Australia. Numerical simulations of steady-state coreflooding experiments are conducted at a number of injection rates using a single set of input characteristic relative permeability curves. Effective relative permeability is then calculated from the simulation data using standard interpretation methods for calculating relative permeability from steady-state tests. Results show that simplified approaches may be used to determine flowrate-independent characteristic relative permeability provided flow rate is sufficiently high, and the core heterogeneity is relatively low. It is also shown that characteristic relative permeability can be determined at any typical flowrate, and even for geologically complex models, when using accurate three-dimensional models.

  18. Small-bowel permeability in collagenous colitis

    Wildt, Signe; Madsen, Jan L; Rumessen, Jüri J


    , indicating that CC is a pan-intestinal disease. In small-intestinal disease, the intestinal barrier function may be impaired, and the permeability of the small intestine altered. The purpose of this research was to study small-bowel function in patients with CC as expressed by intestinal permeability....

  19. Intercomparison on measurement of water vapour permeability

    Hansen, Kurt Kielsgaard

    Three different materials are tested - hard woodfibre board - damp proof course - underlay for roofing The water vapour permeability has been measured according to EN ISO 12572 (2001).......Three different materials are tested - hard woodfibre board - damp proof course - underlay for roofing The water vapour permeability has been measured according to EN ISO 12572 (2001)....

  20. ATP-sensitive potassium channels in capillaries isolated from guinea-pig heart

    Schnitzler, Michael Mederos y; Derst, Christian; Daut, Jürgen; Preisig-Müller, Regina


    The full-length cDNAs of two different α-subunits (Kir6.1 and Kir6.2) and partial cDNAs of three different β-subunits (SUR1, SUR2A and SUR2B) of ATP-sensitive potassium (KATP) channels of the guinea-pig (gp) were obtained by screening a cDNA library from the ventricle of guinea-pig heart. Cell-specific reverse-transcriptase PCR with gene-specific intron-spanning primers showed that gpKir6.1, gpKir6.2 and gpSUR2B were expressed in a purified fraction of capillary endothelial cells. In cardiomyocytes, gpKir6.1, gpKir6.2, gpSUR1 and gpSUR2A were detected. Patch-clamp measurements were carried out in isolated capillary fragments consisting of 3–15 endothelial cells. The membrane capacitance measured in the whole-cell mode was 19.9 ± 1.0 pF and was independent of the length of the capillary fragment, which suggests that the endothelial cells were not electrically coupled under our experimental conditions. The perforated-patch technique was used to measure the steady-state current-voltage relation of capillary endothelial cells. Application of K+ channel openers (rilmakalim or diazoxide) or metabolic inhibition (250 μm 2,4-dinitrophenol plus 10 mM deoxyglucose) induced a current that reversed near the calculated K+ equilibrium potential. Rilmakalim (1 μm), diazoxide (300 μm) and metabolic inhibition increased the slope conductance measured at −55 mV by a factor of 9.0 (±1.8), 2.5 (±0.2) and 3.9 (±1.7), respectively. The effects were reversed by glibenclamide (1 μm). Our results suggest that capillary endothelial cells from guinea-pig heart express KATP channels composed of SUR2B and Kir6.1 and/or Kir6.2 subunits. The hyperpolarization elicited by the opening of KATP channels may lead to an increase in free cytosolic Ca2+, and thus modulate the synthesis of NO and the permeability of the capillary wall. PMID:10835035

  1. Application of CHESS single-bounce capillaries at synchrotron beamlines

    Huang, R.; Szebenyi, T.; Pfeifer, M.; Woll, A.; Smilgies, D.-M.; Finkelstein, K.; Dale, D.; Wang, Y.; Vila-Comamala, J.; Gillilan, R.; Cook, M.; Bilderback, D. H.


    Single-bounce capillaries are achromatic X-ray focusing optics that can provide efficient and high demagnification focusing with large numerical apertures. Capillary fabrication at CHESS can be customized according to specific application requirements. Exemplary applications are reviewed in this paper, as well as recent progress on condensers for high-resolution transmission X-ray microscopy and small focal size capillaries.

  2. Evaluation of brain tumor endothelial permeability by dynamic magnetic resonance Magnevist contrast imaging on a low-field MR-tomograph

    In order to study the endothelial permeability to hydrophilic macromolecules in brain tumors the technique for evaluating the Gd-DTPA absorption kinetics on results of dynamic MRI performed by means of the low-field MR-tomograph Magnetom Open and for calculating the index of blood-tumor GdDTPA transport is developed. 27 patients with various brain tumors are examined. The indices of Magnevist transport to tumor tissue vary substantially, depending on the degree of malignancy and deliver essential information on permeability of tumor capillary bed

  3. Different Methods of Predicting Permeability in Shale

    Mbia, Ernest Ncha; Fabricius, Ida Lykke; Krogsbøll, Anette

    Permeability is often very difficult to measure or predict in shale lithology. In this work we are determining shale permeability from consolidation tests data using Wissa et al., (1971) approach and comparing the results with predicted permeability from Kozeny’s model. Core and cuttings materials...... were obtained from Fjerritslev shale Formation in Juassic interval of Stenlille and Vedsted on-shore wells of Danish basin. The calculated permeability from specific surface and porosity vary from 0.09 to 48.53 μD while that calculated from consolidation tests data vary from 1000 μD at a low vertical...... effective stress to 9 μD at high vertical effective stress of 100 MPa. The indirect permeability calculated from consolidation tests falls in the same magnitude at higher vertical effective stress, above 40 MPa, as that of the Kozeny model for shale samples with high non-clay content ≥ 70% but are higher by...

  4. Numerical simulations of capillary barrier field tests

    Morris, C.E. [Univ. of Wollongong (Australia); Stormont, J.C. [Univ. of New Mexico, Albuquerque, NM (United States)


    Numerical simulations of two capillary barrier systems tested in the field were conducted to determine if an unsaturated flow model could accurately represent the observed results. The field data was collected from two 7-m long, 1.2-m thick capillary barriers built on a 10% grade that were being tested to investigate their ability to laterally divert water downslope. One system had a homogeneous fine layer, while the fine soil of the second barrier was layered to increase its ability to laterally divert infiltrating moisture. The barriers were subjected first to constant infiltration while minimizing evaporative losses and then were exposed to ambient conditions. The continuous infiltration period of the field tests for the two barrier systems was modelled to determine the ability of an existing code to accurately represent capillary barrier behavior embodied in these two designs. Differences between the field test and the model data were found, but in general the simulations appeared to adequately reproduce the response of the test systems. Accounting for moisture retention hysteresis in the layered system will potentially lead to more accurate modelling results and is likely to be important when developing reasonable predictions of capillary barrier behavior.

  5. Modeling of Throttling Process inside Capillary Tube

    Vinš, Václav; Vacek, V.

    Praha : ČVUT, 2009, s. 250-251. ISBN 978-80-01-04286-1. [ANNUAL CTU UNIVERSITY-WIDE SEMINAR /18./. Praha (CZ), 16.02.2009-20.02.2009] Institutional research plan: CEZ:AV0Z20760514 Keywords : capillary tube * numerical model * metastable flow Subject RIV: BJ - Thermodynamics

  6. Planetary In Situ Capillary Electrophoresis System (PISCES)

    Willis, P. A.; Stockton, A. M.; Mora, M. F.; Cable, M. L.; Bramall, N. E.; Jensen, E. C.; Jiao, H.; Lynch, E.; Mathies, R. A.


    We propose to develop PISCES, a 3-kg, 2W, flight-capable microfluidic lab-on-a-chip capillary electrophoresis analyzer capable of ingesting solid, liquid, or gas samples and performing a suite of chemical analyses with parts per trillion sensitivity.

  7. Imbibition of ``Open Capillary'': Fundamentals and Applications

    Tani, Marie; Kawano, Ryuji; Kamiya, Koki; Okumura, Ko


    Control or transportation of small amount of liquid is one of the most important issues in various contexts including medical sciences or pharmaceutical industries to fuel delivery. We studied imbibition of ``open capillary'' both experimentally and theoretically, and found simple scaling laws for both statics and dynamics of the imbibition, similarly as that of imbibition of capillary tubes. Furthermore, we revealed the existence of ``precursor film,'' which developed ahead of the imbibing front, and the dynamics of it is described well by another scaling law for capillary rise in a corner. Then, to show capabilities of open capillaries, we demonstrated two experiments by fabricating micro mixing devices to achieve (1) simultaneous multi-color change of the Bromothymol blue (BTB) solution and (2) expression of the green florescent protein (GFP). This research was partly supported by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan). M. T. is supported by the Japan Society for the Promotion of Science Research Fellowships for Young Scientists.

  8. Analytical biotechnology: Capillary electrophoresis and chromatography

    The papers describe the separation, characterization, and equipment required for the electrophoresis or chromatography of cyclic nucleotides, pharmaceuticals, therapeutic proteins, recombinant DNA products, pheromones, peptides, and other biological materials. One paper, On-column radioisotope detection for capillary electrophoresis, has been indexed separately for inclusion on the data base

  9. Macroscopic theory for capillary-pressure hysteresis.

    Athukorallage, Bhagya; Aulisa, Eugenio; Iyer, Ram; Zhang, Larry


    In this article, we present a theory of macroscopic contact angle hysteresis by considering the minimization of the Helmholtz free energy of a solid-liquid-gas system over a convex set, subject to a constant volume constraint. The liquid and solid surfaces in contact are assumed to adhere weakly to each other, causing the interfacial energy to be set-valued. A simple calculus of variations argument for the minimization of the Helmholtz energy leads to the Young-Laplace equation for the drop surface in contact with the gas and a variational inequality that yields contact angle hysteresis for advancing/receding flow. We also show that the Young-Laplace equation with a Dirichlet boundary condition together with the variational inequality yields a basic hysteresis operator that describes the relationship between capillary pressure and volume. We validate the theory using results from the experiment for a sessile macroscopic drop. Although the capillary effect is a complex phenomenon even for a droplet as various points along the contact line might be pinned, the capillary pressure and volume of the drop are scalar variables that encapsulate the global quasistatic energy information for the entire droplet. Studying the capillary pressure versus volume relationship greatly simplifies the understanding and modeling of the phenomenon just as scalar magnetic hysteresis graphs greatly aided the modeling of devices with magnetic materials. PMID:25646688

  10. Numerical simulations of capillary barrier field tests

    Numerical simulations of two capillary barrier systems tested in the field were conducted to determine if an unsaturated flow model could accurately represent the observed results. The field data was collected from two 7-m long, 1.2-m thick capillary barriers built on a 10% grade that were being tested to investigate their ability to laterally divert water downslope. One system had a homogeneous fine layer, while the fine soil of the second barrier was layered to increase its ability to laterally divert infiltrating moisture. The barriers were subjected first to constant infiltration while minimizing evaporative losses and then were exposed to ambient conditions. The continuous infiltration period of the field tests for the two barrier systems was modelled to determine the ability of an existing code to accurately represent capillary barrier behavior embodied in these two designs. Differences between the field test and the model data were found, but in general the simulations appeared to adequately reproduce the response of the test systems. Accounting for moisture retention hysteresis in the layered system will potentially lead to more accurate modelling results and is likely to be important when developing reasonable predictions of capillary barrier behavior