Semilog Analysis of the Pulse-Decay Technique of Permeability Measurement

1984 ◽  
Vol 24 (06) ◽  
pp. 639-642 ◽  
Author(s):  
Techien Chen ◽  
P.W. Stagg
Keyword(s):  
Experimental Data ◽  
Pressure Difference ◽  
Constant Pressure ◽  
Error Function ◽  
Initial Pressure ◽  
Core Sample ◽  
Alternative Solution ◽  
Dimensionless Time ◽  
Permeability Measurement ◽  
The Core

Semilog Analysis of the Pulse-Decay Technique Pulse-Decay Technique of Permeability Measurement Abstract An alternative solution to the system of equations describing the pulse-decay technique of permeability measurement has been obtained. It is a solution in which the sample PV is not neglected. The experimental data are analyzed by using the slope of a semilog plot to evaluate permeability. permeability. Introduction The pulse-decay technique of permeability measurement has been used by workers interested in radioactive waste storage and low-permeability gas reservoirs. The basic idea of this method is to allow the pressure in two vessels, initially maintained at different pressures, equilibrate by flowing through a core sample. The permeability of the sample then can be determined from permeability of the sample then can be determined from the pressure-decay record. Brace et al. assumed that the compressibility of the rock matrix is negligible compared with that of the pore fluid and that the PV is negligible compared with the downstream volume. Subsequent attempts have been made to eliminate one or both of these assumptions by numerical 12.4 or analytical solutions. Of these solutions, the error-function solution of Bourbie and Walls is particularly well suited to experimental-data reduction. However the applicable range of their solution is limited to dimensionless time, tD, of less than unity and a ratio of PV to downstream volume, y, of less than 0.6. This paper presents an alternative solution that is not restricted paper presents an alternative solution that is not restricted by to or y. It reduces to an exponential-decay solution similar to Brace et al.'s solution when to is greater than 0. 3. Experimental Setup A schematic of the setup is shown in Fig. 1. A cylindrical core sample is mounted inside the coreholder and hydrostatic pressure is applied to the circumference and ends of the sample. With Valves 1 and 2 open, nitrogen is pumped into Vessel 1 to a pressure of p 0. When the pressure in the system has reached equilibrium, Valves pressure in the system has reached equilibrium, Valves 1 and 2 are closed and the pressure in Vessel 1 is raised slightly to pi. A few minutes are allowed for the temperature and pressure in Vessel 1 to equilibrate. The test begins at time t=O with the opening of Valve 1. The differential pressure transducer measures the pressure drop as the gas in the large Vessel 1 flows through the core into the small Vessel 2. The test continues until the pressure difference is 50 to 80% of the initial pressure pressure difference is 50 to 80% of the initial pressure difference. Theory The diffusion equation for flow across the core is .....................................(1) where p1-p(x, t) PD (xD, tD = ., ............(2) PD (xD, tD = ., ............(2) p1-p02 Xd=x/L,..............................(3) .....................................(4) p1 is the constant pressure of the upstream vessel, p02 p1 is the constant pressure of the upstream vessel, p02 is the initial pressure of Vessel 2, L is the length of the core, and the rest of the symbols are as defined in the nomenclature. The initial and boundary conditions are PD (xD,0)=1,.........................(5) PD (xD,0)=1,.........................(5) Pd (0, tD)=0,.........................(6) Pd (0, tD)=0,.........................(6) and .....................................(7) where .....................................(8) A is the cross-sectional area of the core sample, and V2, is the volume of Vessel 2. Therefore, is the ratio of the PV to the volume of Vessel 2. SPEJ P. 639

scholarly journals Searching for optimum adsorption curve for metal sorption on soils: comparison of various isotherm models fitted by different error functions

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Péter Sipos
Keyword(s):  
Experimental Data ◽  
Error Function ◽  
Isotherm Models ◽  
Metal Sorption ◽  
Error Functions ◽  
Sorption System ◽  
Geochemical Properties ◽  
Function Combination ◽  
Soil Metal ◽  
Sorption Curve

AbstractStudies comparing numerous sorption curve models and different error functions are lacking completely for soil-metal adsorption systems. We aimed to fill this gap by studying several isotherm models and error functions on soil-metal systems with different sorption curve types. The combination of fifteen sorption curve models and seven error functions were studied for Cd, Cu, Pb, and Zn in competitive systems in four soils with different geochemical properties. Statistical calculations were carried out to compare the results of the minimizing procedures and the fit of the sorption curve models. Although different sorption models and error functions may provide some variation in fitting the models to the experimental data, these differences are mostly not significant statistically. Several sorption models showed very good performances (Brouers-Sotolongo, Sips, Hill, Langmuir-Freundlich) for varying sorption curve types in the studied soil-metal systems, and further models can be suggested for certain sorption curve types. The ERRSQ error function exhibited the lowest error distribution between the experimental data and predicted sorption curves for almost each studied cases. Consequently, their combined use could be suggested for the study of metal sorption in the studied soils. Besides testing more than one sorption isotherm model and error function combination, evaluating the shape of the sorption curve and excluding non-adsorption processes could be advised for reliable data evaluation in soil-metal sorption system.

SEMIEMPIRICAL SCF–LCAO–MO TREATMENT OF THIOPHENE, FURAN, AND PYRROLE

1965 ◽  
Vol 43 (5) ◽  
pp. 1569-1576 ◽  
Author(s):  
N. Solony ◽  
F. W. Birss ◽  
John B. Greenshields
Keyword(s):  
Experimental Data ◽  
Satisfactory Agreement ◽  
Electronic Structures ◽  
Spectroscopic Data ◽  
Variable Parameter ◽  
Coulomb Repulsion ◽  
Resonance Integral ◽  
Electronic Transitions ◽  
The Core ◽  
Lcao Mo

The semiempirical SCF–LCAO–MO method of Pariser–Parr–Pople is utilized in the study of the π-electronic structures of thiophene, furan, and pyrrole. The core Hamiltonian expansion contains a Uz++ term, the potential due to the ionized hetero-atom contributing two electrons to the π-system. The γzz, one-center coulomb repulsion integral for the hetero-atom is evaluated from the experimental spectroscopic data only. With the resonance integral βczc as the only variable parameter, the calculated π*–π electronic transitions are in a satisfactory agreement with the experimental data.

The Petrogenetic Model, an Extension of Bowen's Petrogenetic Grid

1962 ◽  
Vol 99 (6) ◽  
pp. 558-569 ◽  
Author(s):  
Peter J. Wyllie
Keyword(s):  
Experimental Data ◽  
Constant Pressure ◽  
Three Dimensional ◽  
Pore Fluid ◽  
Fluid Composition ◽  
Solid Reaction ◽  
Petrogenetic Model ◽  
Wide Range ◽  
Opposite Face ◽  
Reaction Surfaces

AbstractBowen's petrogenetic grid is a PT projection containing univariant curves for decarbonation, dehydration, and solid-solid reactions, with vapour pressure (Pf) equal to total pressure (Ps). Analysis of experimental data in the system MgO–CO2–H2O leads to an expansion of this grid. Three of the important variables in metamorphism when Pf = Ps are P, T, and variation of the pore fluid composition between H2O and CO2. These can be illustrated in a three-dimensional petrogenetic model; one face is a PT plane for reactions occurring with pure H2O, and the opposite face is a similar plane for reactions with pure CO2; these are separated by an axis for pore fluid composition varying between H2O and CO2. Superposition of the PT faces of the model provides the petrogenetic grid. The reactions within the model are represented by divariant surfaces, which may meet along univariant lines. For dissociation reactions, the surfaces curve towards lower temperatures as the proportion of non-reacting volatile increases, and solid-solid reaction surfaces are parallel to the vapour composition axis and perpendicular to the PT axes. The relative temperatures of reactions and the lines of intersections of the surfaces can be illustrated in isobaric sections. Isobaric sections are used to illustrate reactions proceeding at constant pressure with (1) pore fluid composition remaining constant during the reaction, with temperature increasing (2) pore fluid composition changing during the reaction, with temperature increasing, and (3) pore fluid changing composition at constant temperature. The petrogenetic model provides a convenient framework for a wide range of experimental data.

Abstract P457: Systems Analysis To Understand The Impact Of The CDK Module On Cardiomyocyte Proliferation

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Bryana N Harris ◽  
Laura Woo ◽  
Jeffrey J Saucerman
Keyword(s):  
Experimental Data ◽  
Cell Cycle ◽  
Transcription Factor ◽  
Dna Synthesis ◽  
Current Knowledge ◽  
Cycle Phase ◽  
Cyclin D ◽  
Cardiomyocyte Proliferation ◽  
The Core ◽  
The Impact

Rationale: Heart failure is caused by the inability of adult mammalian hearts to overcome the loss of cardiomyocytes (CMs). This is due partly to the limited proliferative capacity of CMs, which exit the cell cycle and do not undergo cell division. Current knowledge in cardiac regeneration lacks an understanding of the molecular regulatory networks that determine whether CMs will progress through the cell cycle to proliferate. Our goal is to use computational modeling to understand the expression and activation levels of the core cell cycle network, specifically cyclins and cyclin-cyclin-dependent kinase (CDK) complexes. Methods: A model of core cell cycle dynamics was curated using previously published studies of CM proliferation regulators. This model incorporates those regulators known to stimulate G1/S and G2/M transitions through the core CDKs. The activity of each of the 22 network nodes (22 reactions) was predicted using a logic-based differential equation approach. The CDK model was then coupled with a minimal ODE model of cell cycle phase distributions and validated based on descriptions and experimental data from the literature. To prioritize key nodes for experimental validation, we performed a sensitivity analysis by stimulating individual knockdown for every node in the network, measuring the fractional activity of all nodes. Results: Our model confirmed that the knockdown of p21 and Rb protein and the overexpression of E2F transcription factor and cyclinD-cdk4 showed an increase in cells going through DNA synthesis and entering mitosis. A combined knockdown of p21 and p27 showed an increase of cells entering mitosis. Cyclin D-cdk4 and p21 overexpression showed a decrease and increase of Rb expression, respectively. Of the 14 model predictions, 12 agreed with experimental data in the literature. A comprehensive knockdown of the model nodes suggests that E2F (a key transcription factor driving DNA synthesis) is positively regulated by cyclin D while negatively regulated by GSK3B, SMAD3, and pRB. Conclusion: This model enables us to predict how cardiomyocytes respond to stimuli in the CDK network and identify potential therapeutic regulators that induce cardiomyocyte proliferation.

Prediction of Cavitation Inception Within Regions of Flow Separation

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Eduard Amromin
Keyword(s):  
Experimental Data ◽  
Turbulent Flow ◽  
Flow Separation ◽  
Computational Method ◽  
Average Flow ◽  
Cavitation Inception ◽  
The Core ◽  
Good Agreement

Cavitation within regions of flow separation appears in drifting vortices. A two-part computational method is employed for prediction of cavitation inception number there. The first part is an analysis of the average flow in separation regions without consideration of an impact of vortices. The second part is an analysis of equilibrium of the bubble within the core of a vortex located in the turbulent flow of known average characteristics. Computed cavitation inception numbers for axisymmetric flows are in the good agreement with the known experimental data.

scholarly journals CO2-brine injectivity tests in high co2 content carbonate field, sarawak basin, offshore east Malaysia

2019 ◽  
Vol 89 ◽  
pp. 04005 ◽  
Author(s):  
A Giwelli ◽  
MZ Kashim ◽  
MB Clennell ◽  
L Esteban ◽  
R Noble ◽  
...  
Keyword(s):  
Packed Column ◽  
Core Sample ◽  
Chemical Analyses ◽  
Core Flooding ◽  
Flow Rates ◽  
X Ray ◽  
The Core ◽  
Reservoir Conditions ◽  
Post Test ◽  
Porosity And Permeability

We conducted relatively long duration core-flooding tests on three representative core samples under reservoir conditions to quantify the potential impact of flow rates on fines production/permeability change. Supercritical CO2 was injected cyclically with incremental increases in flow rate (2─14 ml/min) with live brine until a total of 7 cycles were completed. To avoid unwanted fluid-rock reaction when live brine was injected into the sample, and to mimic the in-situ geochemical conditions of the reservoir, a packed column was installed on the inflow accumulator line to pre-equilibrate the fluid before entering the core sample. The change in the gas porosity and permeability of the tested plug samples due to different mechanisms (dissolution and/or precipitation) that may occur during scCO2/live brine injection was investigated. Nuclear magnetic resonance (NMR) T2 determination, X-ray CT scans and chemical analyses of the produced brine were also conducted. Results of pre- and post-test analyses (poroperm, NMR, X-ray CT) showed no clear evidence of formation damage even after long testing cycles and only minor or no dissolution (after large injected pore volumes (PVs) ~ 200). The critical flow rates (if there is one) were higher than the maximum rates applied. Chemical analyses of the core effluent showed that the rock samples for which a pre-column was installed do not experience carbonate dissolution.

scholarly journals Moisture Absorption Effects on the Mechanical Properties of Sandwich Biocomposites with Cork Core and Flax/PLA Face Sheets

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7295
Author(s):  
Hom Nath Dhakal ◽  
Chulin Jiang ◽  
Moumita Sit ◽  
Zhongyi Zhang ◽  
Moussa Khalfallah ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Failure Modes ◽  
Moisture Absorption ◽  
Mechanical Performance ◽  
Core Sample ◽  
Environmental Benefits ◽  
Matrix Cracking ◽  
Core Material ◽  
Poly Lactic Acid ◽  
The Core

The aim of this study was to evaluate the moisture absorption behaviour and its influence on the mechanical properties of newly developed sandwich biocomposites with flax fibre-reinforced poly-lactic acid (PLA) face sheets and soft cork as the core material. Three different types of sandwich biocomposite laminates comprised of different layup configurations, namely, non-woven flax/PLA (Sample A), non-woven flax/PLA and cork as core (Sample B) and non-woven flax/paper backing/PLA, cork as core (Sample C), were fabricated. In order to evaluate the influence of moisture ingress on the mechanical properties, the biocomposites were immersed in seawater for a period of 1200 h. The biocomposites (both dry and water immersed) were then subjected to tensile, flexural and low-velocity falling weight impact tests. It was observed from the experimental results that the moisture uptake significantly influenced the mechanical properties of the biocomposites. The presence of the cork and paper in sample C made it more susceptible to water absorption, reaching a value of 34.33%. The presence of cork in the core also has a considerable effect on the mechanical, as well as energy dissipation, behaviours. The results of sample A exhibited improved mechanical performance in both dry and wet conditions compared to samples B and C. Sample A exhibits 32.6% more tensile strength and 81.4% more flexural strength in dry conditions than that in sample C. The scanning electron microscopy (SEM) and X-ray micro-CT images revealed that the failure modes observed are a combination of matrix cracking, core crushing and face core debonding. The results from this study suggest that flax/PLA sandwich biocomposites can be used in various lightweight applications with improved environmental benefits.

scholarly journals Design and Manufacture of Data Gloves for Rehabilitation Training and Gesture Recognition Based on Flexible Sensors

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Kai Guo ◽  
Senhao Zhang ◽  
Shasha Zhao ◽  
Hongbo Yang
Keyword(s):  
Experimental Data ◽  
Gesture Recognition ◽  
The Self ◽  
Hand Rehabilitation ◽  
Data Glove ◽  
Flexible Sensors ◽  
Rehabilitation Training ◽  
Flexible Sensor ◽  
The Core ◽  
Design And Manufacture

This work takes the production and usage scenarios of the data glove as the research object and studies the method of applying the flexible sensor to the data glove. Many studies are also devoted to exploring the transplantation of flexible sensors to data gloves. However, this type of research still lacks the display of specific application scenarios such as gesture recognition or hand rehabilitation training. A small amount of experimental data and theoretical analysis are difficult to promote the development of flexible sensors and flexible data gloves design schemes. Therefore, this study uses the self-made flexible sensor of the research group as the core sensing unit to produce a flexible data glove to monitor the bending changes of the knuckles and then use it for simple gesture recognition and rehabilitation training.

Effect of glycidyl methacrylate (GMA) on the stability of acrylic latex

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Guangfeng Wu ◽  
Yue Tao ◽  
Hong Kang ◽  
Huixuan Zhang
Keyword(s):  
Experimental Data ◽  
Glycidyl Methacrylate ◽  
Sodium Dodecyl ◽  
The Other ◽  
Lower Amount ◽  
Core Shell ◽  
Acrylic Latex ◽  
The Core ◽  
Shell Particles ◽  
The Stability

AbstractThe stability of core-shell particles (CSPs) with butyl acrylate (BA) as the core and methyl methacrylate (MMA)/glycidyl methacrylate (GMA) mixture in various compositions as the shell was investigated by turbidity measurements. The experiments demonstrate that lower amount addition of GMA could not improve the latex stability. When the amount of GMA exceeded 2% of the total reactants, it began to improve the stability of the latex. With the increasing content of GMA, the latex became more and more stable. On the other hand, experimental data also show that the stability was improved by increasing the concentration of sodium dodecyl sulfate (SDS).

scholarly journals Experimental and Numerical Study on Hydromechanical Coupled Deformation Behavior of Beishan Granite considering Permeability Evolution

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Z. H. Wang ◽  
W. G. Ren ◽  
Y. L. Tan ◽  
Heinz Konietzky
Keyword(s):  
Pressure Difference ◽  
Numerical Study ◽  
Volumetric Strain ◽  
Initial Pressure ◽  
Numerical Code ◽  
Permeability Evolution ◽  
Beishan Granite ◽  
Pore Pressures ◽  
Damaged Zone ◽  
Hlw Repository

Beishan granite is a potential host rock for a high-level radioactive waste (HLW) repository in China. Understanding the hydromechanical (HM) behavior and permeability evolution of Beishan granite is important for the HLW repository safety. Therefore, the granite of Beishan in Gansu province was studied. HM coupled tests are carried out on Beishan granite under different pore pressures. The results show that the initial pressure difference has little influence on permeability measurement before dilatancy starts. However, after onset of dilatancy, the permeability increases with the increasing initial pressure difference. The initial permeability of Beishan granite is about 10−18 m2 under a confining pressure of 20 MPa. In the initial loading phase, the permeability shows a relatively large reduction. Then, the permeability almost keeps constant until dilatancy starts. From dilatancy point to peak stress, permeability increases linearly with volumetric strain. The proposed permeability evolution rule is implemented into a numerical code to perform HM coupled simulations. The simulation results show that the damaged zone first appears at the model boundary and then extends to the inside, forming high volumetric strain areas. And it provides seepage channels for fluid flow. The macroscopic fracture patterns indicate that pore pressure accelerates rock degradation during HM coupling. The obtained results help to understand the damage mechanisms of granite caused by pore pressures and are of great importance for the safety of a HLW repository.

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