Rock compressibility from microcomputed tomography images: Controls on digital rock simulations

Geophysics ◽  
2019 ◽  
Vol 84 (4) ◽  
pp. WA127-WA139 ◽  
Author(s):  
Nishank Saxena ◽  
Ronny Hofmann ◽  
Amie Hows ◽  
Erik H. Saenger ◽  
Luca Duranti ◽  
...  
Keyword(s):  
Microcomputed Tomography ◽  
Image Resolution ◽  
Production Performance ◽  
Reservoir Rock ◽  
Micro Ct ◽  
Sandstone Sample ◽  
Digital Rock ◽  
Relative Contribution ◽  
Rock Compressibility

Rock compressibility is a major control of reservoir compaction, yet only limited core measurements are available to constrain estimates. Improved analytical and computational estimates of rock compressibility of reservoir rock can improve forecasts of reservoir production performance and the geomechanical integrity of compacting reservoirs. The fast-evolving digital rock technology can potentially overcome the need for simplification of pores (e.g., ellipsoids) to estimate rock compressibility as the computations are performed on an actual pore-scale image acquired using 3D microcomputed tomography (micro-CT). However, the computed compressibility using a digital image is impacted by numerous factors, including imaging conditions, image segmentation, constituent properties, choice of numerical simulator, rock field of view, how well the grain contacts are resolved in an image, and the treatment of grain-to-grain contacts. We have analyzed these factors and quantify their relative contribution to the rock moduli computed using micro-CT images of six rocks: a Fontainebleau sandstone sample, two Berea sandstone samples, a Castelgate sandstone sample, a grain pack, and a reservoir rock. We find that image-computed rock moduli are considerably stiffer than those inferred using laboratory-measured ultrasonic velocities. This disagreement cannot be solely explained by any one of the many controls when considered in isolation, but it can be ranked by their relative contribution to the overall rock compressibility. Among these factors, the image resolution generally has the largest impact on the quality of image-derived compressibility. For elasticity simulations, the quality of an image resolution is controlled by the ratio of the contact length and image voxel size. Images of poor resolution overestimate contact lengths, resulting in stiffer simulation results.

scholarly journals Effect of BioPlus YC Probiotic Supplementation on Gut Microbiota, Production Performance, Carcass and Meat Quality of Pigs

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1581
Author(s):  
Artur Rybarczyk ◽  
Elżbieta Bogusławska-Wąs ◽  
Alicja Dłubała
Keyword(s):  
Bacillus Subtilis ◽  
Meat Quality ◽  
Bacillus Licheniformis ◽  
Average Daily Gain ◽  
Production Performance ◽  
Probiotic Bacteria ◽  
Control Group ◽  
Production Traits ◽  
Feed Conversion

The objective of the study was to determine the effects of probiotic bacteria Bacillus licheniformis and Bacillus subtilis on microbiological properties of feed mixtures and on the digestive tract content as applicable to production traits and carcass characteristics of fatteners. The experiment was performed on 83,838 fatteners from four successive (insertions) productions in two groups. From the seventy eighth day of age till marketing to the slaughter plant, the pigs were supplied with BioPlus YC probiotic (Chr. Hansen) in the amount of 400 g/t. The preparation contained a complex of probiotic bacteria Bacillus licheniformis DSM 5749, and Bacillus subtilis DSM 5750 spores in a 1:1 ratio. From the fourth insertion, after reaching a body weight of approximately 112 kg, 60 fatteners were selected from each group to measure carcass quality and half of them for meat quality evaluation. Moreover, microbiological analyses in feed and colon were performed. The study showed that BioPlus YC probiotics supplementation resulted in a significantly higher count of B. subtilis and B. licheniformis in the feed, a higher count of B. subtilis, B. licheniformis and LAB, as well as a lower count of Enterobacteriaceae, Enterococcus, Clostridium and Bacillus sp. in the mucosa and in the colorectal content of the test pigs. Our work has shown that supplementation with the BioPlus YC probiotic had a positive effect on the production traits of pigs mainly by reducing mortality (2.83%, p = 0.010), lowering feed conversion ratio—FCR (2.59 kg/kg, p = 0.013), better average daily gain—ADG (0.95 kg/day, p = 0.002) and shorter fattening period (77.25 days, p = 0.019) when compared to the control group (4.19%; 2.79 kg/kg; 0.89 kg/day; 92.8 days, respectively). The addition of the specific Bacillus bacteria did not influence carcass and meat characteristics of the test fatteners.

Filling quality of several obturation techniques in the presence of apically separated instruments: A Micro‐CT study

2020 ◽  
Author(s):  
Sevinç Aktemur Türker ◽  
Emel Uzunoğlu‐Özyürek ◽  
Sena Kaşikçi ◽  
Melike Öndeş ◽  
Ferhat Geneci ◽  
...  
Keyword(s):  
Micro Ct

scholarly journals Validation of Digital Rock Physics Algorithms

Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 669
Author(s):  
Rongrong Lin ◽  
Leon Thomsen
Keyword(s):  
Rock Physics ◽  
Image Resolution ◽  
Staggered Grid ◽  
Static Properties ◽  
Shear Moduli ◽  
Digital Rock Physics ◽  
Digital Rock ◽  
Saturated Rock ◽  
Theoretical Predictions ◽  
Theoretical Test

With a detailed microscopic image of a rock sample, one can determine the corresponding 3-D grain geometry, forming a basis to calculate the elastic properties numerically. The issues which arise in such a calculation include those associated with image resolution, the registration of the digital numerical grid with the digital image, and grain anisotropy. Further, there is a need to validate the numerical calculation via experiment or theory. Because of the geometrical complexity of the rock, the best theoretical test employs the Hashin–Shtrikman result that, for an aggregate of two isotropic components with equal shear moduli, the bulk modulus is uniquely determined, independent of the micro-geometry. Similarly, for an aggregate of two isotropic components with a certain combination of elastic moduli defined herein, the Hashin–Shtrikman formulae give a unique result for the shear modulus, independent of the micro-geometry. For a porous, saturated rock, the solid incompressibility may be calculated via an “unjacketed” test, independent of the micro-geometry. Any numerical algorithm proposed for digital rock physics computation should be validated by successfully confirming these theoretical predictions. Using these tests, we validate a previously published staggered-grid finite difference damped time-stepping algorithm to calculate the static properties of digital rock models.

The Relevance of Personal Domain Satisfaction for the Quality of Life in South Africa

1988 ◽  
Vol 18 (3) ◽  
pp. 69-75 ◽  
Author(s):  
Valerie Møller
Keyword(s):  
Quality Of Life ◽  
South African ◽  
Well Being ◽  
Positive Influence ◽  
Subjective Well Being ◽  
South Africans ◽  
Relative Contribution ◽  
Personal Domain ◽  
The Impact

South African psychologists have identified the improvement of quality of life as a major goal of the 1980s. This paper reviews the impact of satisfaction with personal aspects of life on perceived well-being. The results of an exploratory study of South African quality of life conducted among 5 587 individuals of all population groups are discussed. Findings confirm the salience of the personal domain and the positive influence of personal satisfactions on subjective well-being. However, results of regression analyses suggest that the relative contribution of satisfactions in the personal domain is too low to play a major role in improving the quality of life of all South Africans in the longer term.

Digital rock physics and application of high-resolution micro-CT techniques for geomaterials

2018 ◽  
pp. 299-307 ◽  
Author(s):  
Bankim Mahanta ◽  
P.G. Ranjith ◽  
T.N. Singh ◽  
Vikram Vishal ◽  
WenHui Duan ◽  
...  
Keyword(s):  
High Resolution ◽  
Rock Physics ◽  
Micro Ct ◽  
Digital Rock Physics ◽  
Digital Rock

scholarly journals Trends and Decomposition of Wheat Production in Western Maharashtra

2020 ◽  
pp. 69-78
Author(s):  
P. P. Baviskar ◽  
U. T. Dangore ◽  
A. D. Dhunde ◽  
U. P. Gaware ◽  
A. G. Kadu
Keyword(s):  
Decomposition Analysis ◽  
Parametric Models ◽  
Production Performance ◽  
Wheat Crop ◽  
Secondary Source ◽  
Research Activity ◽  
Wheat Production ◽  
Area Effect ◽  
Relative Contribution ◽  
Almost All

The study was aimed to investigate the production performance of wheat in western Maharashtra. The data of 20 years regarding area, production and productivity of wheat was made available through the secondary source for all the districts of the western Maharashtra region. The study period of 1996-97 to 2015-16 was split into two sub periods i.e. period-I (1996-97 to 2005-2006), period-II (2006-07 to 2015-16) and overall period. The growth rates were calculated using the exponential function. The instability in area, production, and productivity was measured with a coefficient of variation (CV) and Cuddy Della Valle’s Instability index. The relative contribution of area and yield to change in output was estimated by Minhas decomposition model. The district-wise analysis was carried out which resulted that, during the period-I and period-II, almost all districts in the western Maharashtra region registered negative growth including the region as a whole. The area and productivity showed stability in wheat crop in almost all the districts of western Maharashtra region. In the western Maharashtra region, among all the parametric models fitted to the area, production and productivity of wheat crop, the maximum R2 was observed in the case of cubic model in all the districts of Western Maharashtra region with the region as a whole. The region as a whole recorded 59 per cent which marked as the highest R2 in productivity as compared to area and production. The decomposition analysis for western Maharashtra region depicted the largest area effect on wheat production. It was also observed that for both periods the area effect was more pronounced than the yield effect and interaction effect. Hence, there is need for policy maker to formulate development-oriented policies and the researchers to design an investigative research activity for promoting a sustainable wheat production system in the region for expansion of area under wheat cultivation.

scholarly journals ON THE ROLE OF HISTOMORPHOMETRIC (STEREOLOGICAL) MICROSTRUCTURE PARAMETERS IN THE PREDICTION OF VERTEBRAE COMPRESSION STRENGTH

2019 ◽  
Vol 38 (1) ◽  
pp. 63 ◽  
Author(s):  
Leszek Karol Wojnar ◽  
Aneta Gądek-Moszczak ◽  
Jacek Pietraszek
Keyword(s):  
Compression Strength ◽  
Correlation Coefficients ◽  
Diagnostic Techniques ◽  
Micro Ct ◽  
Compression Tests ◽  
Mineral Density ◽  
3D Images ◽  
Microstructure Parameters

The well-documented relation between bone mineral density (BMD) and bone compression strength constitutes the basis for osteoporosis diagnostics and the assessment of fracture risk. Simultaneously, this relation demonstrates a considerable scatter of results as bones of identical mineral density may have significantly different properties. The experimentally confirmed theorem that two materials or tissues of identical microstructure have identical properties leads to the evaluation of various quantitative stereological parameters (also referred to in biomedicine as histomorphology). These parameters, obtained from analysis of 2D or 3D images, have been used in numerous attempts to explain changes in bone strength. Although numerous correlation dependencies, often with high correlation coefficients, were evaluated, we do not know which parameters are worth evaluating, and there is no physical interpretation of these relations. An extended statistical analysis was accomplished on the basis of analysis of 3D images from 23 lumbar (L3) vertebrae scanned with micro-CT and the results of subsequent compression tests. A new parameter called SDF (structure destruction factor) was proposed in order to characterise the quality of 3D trabecular structures, and its significance was demonstrated. The final correlation function, which uses only three stereological parameters, made it possible to predict compression strength with considerable precision. The estimated values correlated very well with the apparent values (correlation coefficient r=0.96). Finally, the stereological parameters most suitable for characterisation of bone compression strength were chosen and a mechanism responsible for the changes in mechanical properties was proposed. The results obtained defined the necessary improvements in diagnostic techniques that would allow for more efficient quantitative microstructure evaluation and guidelines on how to improve treatment of patients with weakened bones.

scholarly journals Effects on egg production and quality of supplementing drinking water with calcium and magnesium

2021 ◽  
Vol 51 (4) ◽  
pp. 469-476
Author(s):  
X.J. Yi ◽  
A. Rehman ◽  
R.W. Akhtar ◽  
A. Abbas ◽  
K. Hussain ◽  
...  
Keyword(s):  
Drinking Water ◽  
Egg Production ◽  
Laying Hens ◽  
Egg Quality ◽  
Production Performance ◽  
Egg Weight ◽  
Calcium And Magnesium ◽  
Eggshell Colour ◽  
Haugh Unit

This study was conducted to appraise the effects on egg quality and production performance of laying hens when drinking water was supplemented with calcium (Ca) and magnesium (Mg). A total of 384 (64-week-old) Hy-line Brown laying hens were assigned at random to four treatments, which consisted of CON: unsupplemented drinking water; T1: drinking water + 2 mg/L Ca + 250 mg/L Mg; T2: drinking water + 4 mg/L Ca + 510 mg/L Mg /10 L; and T3: drinking water + 5 mg/L Ca and 760 mg/L Mg. The experiment lasted six weeks. Water intake increased linearly in week 1 with the rising levels of Ca and Mg in the drinking water. Increasing the Ca and Mg levels improved eggshell strength (week 2 (P =0.01), week 5 (P =0.01), and week 6 (P = 0.03), and eggshell thickness (week 6) (P =0.02) and reduced the rate at which eggs were broken (week 4) (P =0.01). The supplemental Ca and Mg did not affect egg production, egg weight, Haugh unit, albumen height, eggshell colour, and yolk colour compared with CON. Nor did they influence the Haugh unit and albumen height after storing for 1, 5, 10 and 15 days. In conclusion, adding Ca and Mg to the drinking water increased the thickness and strength of the eggshells.

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