scholarly journals Predicting Resistivity and Permeability of Porous Media Using Minkowski Functionals

2019 ◽  
Vol 131 (2) ◽  
pp. 705-722 ◽  
Author(s):  
Per Arne Slotte ◽  
Carl Fredrik Berg ◽  
Hamid Hosseinzade Khanamiri
Keyword(s):  
Surface Roughness ◽  
Predictive Power ◽  
Pore Space ◽  
Random Systems ◽  
Minkowski Functional ◽  
Two Dimensional ◽  
Formation Factor ◽  
Minkowski Functionals ◽  
Functional Value ◽  
Wide Range

AbstractPermeability and formation factor are important properties of a porous medium that only depend on pore space geometry, and it has been proposed that these transport properties may be predicted in terms of a set of geometric measures known as Minkowski functionals. The well-known Kozeny–Carman and Archie equations depend on porosity and surface area, which are closely related to two of these measures. The possibility of generalizations including the remaining Minkowski functionals is investigated in this paper. To this end, two-dimensional computer-generated pore spaces covering a wide range of Minkowski functional value combinations are generated. In general, due to Hadwiger’s theorem, any correlation based on any additive measurements cannot be expected to have more predictive power than those based on the Minkowski functionals. We conclude that the permeability and formation factor are not uniquely determined by the Minkowski functionals. Good correlations in terms of appropriately evaluated Minkowski functionals, where microporosity and surface roughness are ignored, can, however, be found. For a large class of random systems, these correlations predict permeability and formation factor with an accuracy of 40% and 20%, respectively.

Measurements and Predictions of Surface Roughness Effects on the Turbine Vane Aerodynamics

2003 ◽  
Author(s):  
R. J. Boyle ◽  
R. G. Senyitko
Keyword(s):  
Surface Roughness ◽  
Turbulence Models ◽  
Reynolds Numbers ◽  
Aerodynamic Performance ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Roughness Effects ◽  
Linear Cascade ◽  
Wide Range ◽  
Turbine Vane

The aerodynamic performance of a turbine vane was measured in a linear cascade. These measurements were conducted for exit-true chord Reynolds numbers between 150,000 and 1,800,000. The vane surface rms roughness-to-true chord ratio was approximately 2 × 10−4. Measurements were made for exit Mach numbers between 0.3 and 0.9 to achieve different loading distributions. Measurements were made at three different inlet turbulence levels. High and intermediate turbulence levels were generated using two different blown grids. The turbulence was low when no grid was present. The wide range of Reynolds numbers was chosen so that, at the lower Reynolds numbers the rough surfaces would be hydraulically smooth. The primary purpose of the tests was to provide data to verify CFD predictions of surface roughness effects on aerodynamic performance. Data comparisons are made using a two-dimensional Navier-Stokes analysis. Both two-equation and algebraic roughness turbulence models were used. A model is proposed to account for the increase in loss due to roughness as the Reynolds number increases.

scholarly journals Magnetic Resonance Pore Imaging, a new tool for porous media research

2021 ◽  
Author(s):  
◽  
Stefan A. Hertel
Keyword(s):  
Porous Media ◽  
Magnetic Resonance ◽  
Pore Space ◽  
Biological Tissues ◽  
Porous System ◽  
Two Dimensional ◽  
Phase Problem ◽  
Average Pore ◽  
Wide Range ◽  
Pgse Nmr

<p>Porous media are highly prevalent in nature and span a wide range of systems including biological tissues, chemical catalysts or rocks in oil reservoirs. Imaging of the structure of the constituent pores is therefore highly desirable for life sciences and technological applications. This thesis presents the new development and application of a nuclear magnetic resonance (NMR) technique to acquire high resolution images of closed pores. The technique is a further development of diffusive-diffraction Pulsed Gradient Spin Echo (PGSE) NMR, which has been shown to image the pore auto-correlation function averaged over all pores. Until recently it was conventional wisdom that diffusive-diffraction PGSE NMR can only measure the magnitude of the form factor, due to its similarity to diffraction techniques such as x-ray and neutron scattering. In diffraction applications the loss of phase information is commonly referred to as the “phase problem”, which prevents the reconstruction of images of the pore space by inverse Fourier transform. My work is based on a recently suggested modification of the diffusive-diffraction PGSE NMR method, which creates a hybrid between Magnetic Resonance Imaging (MRI) and PGSE NMR. Therefore, we call this approach Magnetic Resonance Pore Imaging (MRPI). We provide experimental confirmation that MRPI does indeed measure the diffractive signal including its phase and thus the “phase problem” is lifted. We suggest a two-dimensional version of MRPI and obtain two-dimensional average pore images of cylindrical and triangular pores with an unprecedented resolution as compared to state of the art MRI. Utilizing a laser machined phantom sample we present images of microscopic pores with triangular shape even in the presence of wall relaxation effects. We therefore show that MRPI is able to reconstruct the pore shape without any prior knowledge or assumption about the porous system under study. Furthermore, we demonstrate that the MRPI approach integrates seamlessly with known MRI concepts. For instance we introduce “MRPI mapping” which acquires the MRPI signal for each pixel in an MRI image. This enables one to resolve pore sizes and shapes spatially, thus expanding the application of MRPI to samples with heterogeneous distributions of pores.</p>

scholarly journals Magnetic Resonance Pore Imaging, a new tool for porous media research

2021 ◽  
Author(s):  
◽  
Stefan A. Hertel
Keyword(s):  
Porous Media ◽  
Magnetic Resonance ◽  
Pore Space ◽  
Biological Tissues ◽  
Porous System ◽  
Two Dimensional ◽  
Phase Problem ◽  
Average Pore ◽  
Wide Range ◽  
Pgse Nmr

<p>Porous media are highly prevalent in nature and span a wide range of systems including biological tissues, chemical catalysts or rocks in oil reservoirs. Imaging of the structure of the constituent pores is therefore highly desirable for life sciences and technological applications. This thesis presents the new development and application of a nuclear magnetic resonance (NMR) technique to acquire high resolution images of closed pores. The technique is a further development of diffusive-diffraction Pulsed Gradient Spin Echo (PGSE) NMR, which has been shown to image the pore auto-correlation function averaged over all pores. Until recently it was conventional wisdom that diffusive-diffraction PGSE NMR can only measure the magnitude of the form factor, due to its similarity to diffraction techniques such as x-ray and neutron scattering. In diffraction applications the loss of phase information is commonly referred to as the “phase problem”, which prevents the reconstruction of images of the pore space by inverse Fourier transform. My work is based on a recently suggested modification of the diffusive-diffraction PGSE NMR method, which creates a hybrid between Magnetic Resonance Imaging (MRI) and PGSE NMR. Therefore, we call this approach Magnetic Resonance Pore Imaging (MRPI). We provide experimental confirmation that MRPI does indeed measure the diffractive signal including its phase and thus the “phase problem” is lifted. We suggest a two-dimensional version of MRPI and obtain two-dimensional average pore images of cylindrical and triangular pores with an unprecedented resolution as compared to state of the art MRI. Utilizing a laser machined phantom sample we present images of microscopic pores with triangular shape even in the presence of wall relaxation effects. We therefore show that MRPI is able to reconstruct the pore shape without any prior knowledge or assumption about the porous system under study. Furthermore, we demonstrate that the MRPI approach integrates seamlessly with known MRI concepts. For instance we introduce “MRPI mapping” which acquires the MRPI signal for each pixel in an MRI image. This enables one to resolve pore sizes and shapes spatially, thus expanding the application of MRPI to samples with heterogeneous distributions of pores.</p>

scholarly journals Wettability in complex porous materials, the mixed-wet state, and its relationship to surface roughness

2018 ◽  
Vol 115 (36) ◽  
pp. 8901-8906 ◽  
Author(s):  
Ahmed AlRatrout ◽  
Martin J. Blunt ◽  
Branko Bijeljic
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Pore Space ◽  
Contact Angles ◽  
Wettability Alteration ◽  
Water Repellent ◽  
Local Degree ◽  
Wide Range ◽  
Mixed Wettability ◽  
The Impact

A quantitative in situ characterization of the impact of surface roughness on wettability in porous media is currently lacking. We use reservoir condition micrometer-resolution X-ray tomography combined with automated methods for the measurement of contact angle, interfacial curvature, and surface roughness to examine fluid/fluid and fluid/solid interfaces inside a porous material. We study oil and water in the pore space of limestone from a giant producing oilfield, acquiring millions of measurements of curvature and contact angle on three millimeter-sized samples. We identify a distinct wetting state with a broad distribution of contact angle at the submillimeter scale with a mix of water-wet and water-repellent regions. Importantly, this state allows both fluid phases to flow simultaneously over a wide range of saturation. We establish that, in media that are largely water wet, the interfacial curvature does not depend on solid surface roughness, quantified as the local deviation from a plane. However, where there has been a significant wettability alteration, rougher surfaces are associated with lower contact angles and higher interfacial curvature. The variation of both contact angle and interfacial curvature increases with the local degree of roughness. We hypothesize that this mixed wettability may also be seen in biological systems to facilitate the simultaneous flow of water and gases; furthermore, wettability-altering agents could be used in both geological systems and material science to design a mixed-wetting state with optimal process performance.

A Lubrication Equation Incorporating Two-Dimensional Roughness Effects, With Emphasis on the Patterned Data Islands of a Recording Disk

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
James White
Keyword(s):  
Surface Roughness ◽  
Multiple Scale ◽  
Industrial Applications ◽  
Two Dimensional ◽  
Roughness Effects ◽  
Design And Optimization ◽  
Lubrication Equation ◽  
Wide Range ◽  
Level Of Understanding ◽  
Dimensional Surface

Current industrial applications require a consideration of two-dimensional surface roughness effects in design and optimization of fluid bearings. Although the influence of striated surface roughness on fluid lubrication is now at a fairly mature level of understanding, the knowledge and understanding of two-dimensional roughness effects is not nearly at the same level as that achieved over the past several decades for one-dimensional striations. The subject of this paper includes the formulation of a practical “roughness averaged” lubrication equation that is appropriate for two-dimensional surface roughness and applicable over a wide range of Knudsen numbers. After derivation by multiple-scale analysis, the resulting lubrication equation is specialized to treat the patterned data islands located on a storage medium as a two-dimensional roughness pattern, and then used to determine the effect of this roughness on the air-bearing interface between recording head slider and disk. The roughness averaged lubrication equation is solved numerically by a variable-grid finite-difference algorithm, and computed results are included for several bearing geometries.

Aromatic Volatile Composition of Celery and Celeriac Cultivars

HortScience ◽  
1990 ◽  
Vol 25 (5) ◽  
pp. 556-559 ◽  
Author(s):  
Fredy Van Wassenhove ◽  
Patrick Dirinck ◽  
Georges Vulsteke ◽  
Niceas Schamp
Keyword(s):  
Volatile Compounds ◽  
Chromatographic Method ◽  
Apium Graveolens ◽  
Volatile Components ◽  
Two Dimensional ◽  
Qualitative Composition ◽  
Volatile Composition ◽  
Wide Range ◽  
Gas Chromatographic Method ◽  
Identification And Quantification

A two-dimensional capillary gas chromatographic method was developed to separate and quantify aromatic volatiles of celery in one analysis. The isolation, identification, and quantification of the volatile compounds of four cultivars of blanching celery (Apium graveolens L. var. dulce) and six cultivars of celeriac (Apium graveolens L. var. rapaceum) are described. The qualitative composition of Likens-Nickerson extracts of both cultivars is similar. The concentration of terpenes and phthalides, the key volatile components, found in various cultivars of both celery and celeriac varied over a wide range.

scholarly journals Health Benefits of Uses and Applications of Moringa oleifera in Bakery Products

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 318
Author(s):  
Paula García Milla ◽  
Rocío Peñalver ◽  
Gema Nieto
Keyword(s):  
Moringa Oleifera ◽  
Essential Amino Acids ◽  
Bakery Products ◽  
Unani Medicine ◽  
Functional Value ◽  
Organoleptic Characteristics ◽  
Wide Range ◽  
Potential Applications ◽  
Medicinal Properties ◽  
Excellent Source

Moringa oleifera belongs to the Moringaceae family and is the best known of the native Moringa oleifera genus. For centuries, it has been used as a system of Ayurvedic and Unani medicine and has a wide range of nutritional and bioactive compounds, including proteins, essential amino acids, carbohydrates, lipids, fibre, vitamins, minerals, phenolic compounds, phytosterols and others. These characteristics allow it to have pharmacological properties, including anti-diabetic, anti-inflammatory, anticarcinogenic, antioxidant, cardioprotective, antimicrobial and hepatoprotective properties. The entire Moringa oleifera plant is edible, including its flowers, however, it is not entirely safe, because of compounds that have been found mainly in the root and bark, so the leaf was identified as the safest. Moringa oleifera is recognised as an excellent source of phytochemicals, with potential applications in functional and medicinal food preparations due to its nutritional and medicinal properties; many authors have experimented with incorporating it mainly in biscuits, cakes, brownies, meats, juices and sandwiches. The results are fascinating, as the products increase their nutritional value; however, the concentrations cannot be high, as this affects the organoleptic characteristics of the supplemented products. The aim of this study is to review the application of Moringa oleifera in bakery products, which will allow the creation of new products that improve their nutritional and functional value.

scholarly journals Investigation of Two-Dimensional Ultrasonic Surface Burnishing Process on 7075-T6 Aluminum

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Zhenyu Zhou ◽  
Qiuyang Zheng ◽  
Cong Ding ◽  
Guanglei Yu ◽  
Guangjian Peng ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Parameter Optimization ◽  
Wear Mechanism ◽  
Feed Rate ◽  
Sample Surface ◽  
Original Sample ◽  
Two Dimensional ◽  
Delamination Wear ◽  
Treated Sample ◽  
Burnishing Process

AbstractA novel two-dimensional ultrasonic surface burnishing process (2D-USBP) is proposed. 7075-T6 aluminum samples are processed by a custom-designed 2D-USBP setup. Parameter optimization of 2D-USBP is conducted to determine the best processing strategy of 7075-T6 aluminum. A uniform design method is utilized to optimize the 2D-USBP process. U13(133) and U7(72) tables are established to conduct parameter optimization. Burnishing depth, spindle speed, and feed rate are taken as the control parameters. The surface roughness and Vickers hardness are taken as the evaluation indicators. It establishes the active control models for surface quality. Dry wear tests are conducted to compare the wear-resistance of the 2D-USBP treated sample and the original sample. Results show that the machining quality of 2D-USBP is best under 0.24 mm burnishing depth, 5000 r/min spindle speed, and 25 mm/min feed rate. The surface roughness Sa of the sample is reduced from 2517.758 to 50.878 nm, and the hardness of the sample surface is improved from 167 to 252 HV. Under the lower load, the wear mechanism of the 2D-USBP treated sample is mainly abrasive wear accompanied by delamination wear, while the wear mechanism of the original sample is mainly delamination wear. Under the higher load, the accumulation of frictional heat on the sample surface transforms the wear mechanisms of the original and the 2D-USBP treated samples into thermal wear.

scholarly journals Prediction of Wide Range Two-Dimensional Refractivity Using an IDW Interpolation Method from High-Altitude Refractivity Data of Multiple Meteorological Observatories

2021 ◽  
Vol 11 (4) ◽  
pp. 1431
Author(s):  
Sungsik Wang ◽  
Tae Heung Lim ◽  
Kyoungsoo Oh ◽  
Chulhun Seo ◽  
Hosung Choo
Keyword(s):  
High Altitude ◽  
Korean Peninsula ◽  
Interpolation Method ◽  
Atmospheric Condition ◽  
Propagation Path ◽  
Two Dimensional ◽  
Data Set ◽  
Wide Range ◽  
Atmospheric Data ◽  
Terrain Surface

This article proposes a method for the prediction of wide range two-dimensional refractivity for synthetic aperture radar (SAR) applications, using an inverse distance weighted (IDW) interpolation of high-altitude radio refractivity data from multiple meteorological observatories. The radio refractivity is extracted from an atmospheric data set of twenty meteorological observatories around the Korean Peninsula along a given altitude. Then, from the sparse refractive data, the two-dimensional regional radio refractivity of the entire Korean Peninsula is derived using the IDW interpolation, in consideration of the curvature of the Earth. The refractivities of the four seasons in 2019 are derived at the locations of seven meteorological observatories within the Korean Peninsula, using the refractivity data from the other nineteen observatories. The atmospheric refractivities on 15 February 2019 are then evaluated across the entire Korean Peninsula, using the atmospheric data collected from the twenty meteorological observatories. We found that the proposed IDW interpolation has the lowest average, the lowest average root-mean-square error (RMSE) of ∇M (gradient of M), and more continuous results than other methods. To compare the resulting IDW refractivity interpolation for airborne SAR applications, all the propagation path losses across Pohang and Heuksando are obtained using the standard atmospheric condition of ∇M = 118 and the observation-based interpolated atmospheric conditions on 15 February 2019. On the terrain surface ranging from 90 km to 190 km, the average path losses in the standard and derived conditions are 179.7 dB and 182.1 dB, respectively. Finally, based on the air-to-ground scenario in the SAR application, two-dimensional illuminated field intensities on the terrain surface are illustrated.

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