scholarly journals Empirical Determination of Sieve Size Statistics from Grain Measurement

2021 ◽  
Author(s):  
◽  
John Edward Adams
Keyword(s):  
Grain Size ◽  
Thin Section ◽  
Shape Change ◽  
Regression Line ◽  
Apparent Size ◽  
Regression Equations ◽  
Simple Addition ◽  
Sieve Size ◽  
Mean Size ◽  
Log Normal

<p>Relationships between sieve grain size and thin section grain size have been determined empirically from the study of 72 artificially created sendstone samples. Modern sands were sieved into size fractions, which were recombined in a log normal distribution to give samples with a range of means and standard deviations, but with similar individual grain properties. Sample splits of these were impregnated with resin, and the size distribution of grain long axes selected by point counter in thin section was compared with that found by sieving the remaining sample. This method attempts to minimise the effects of factors that influence apparent size in thin section. The results have been compared with those of (1958, 1962) who studied the same size relationships in 38 natural sandstones, e.g. This work: Sieve size from Folk = 1.078(thin section mean) + 0.200 phi graphical mean 1/3(Ø16+Ø50+Ø84) Friedman (1958): Sieve size mean from = 0.903(thin section mean) + 0.381 phi combined quartile measures Ø25, Ø50,Ø75 The regression coefficients differ from those of Friedman, probably because of the range of mean sizes investigated in the present work was twice as large (5.7 phi units vs. 2.6 phi units). The correlation coefficient relating sieve to thin section analysis decreases progressively, as Friedman found, from mean (0.992) to standard deviation (0.958), skewness (O.536), and kurtosis (0.249). The correlation for skewness and kurtosis is not significant. The size range was extended to -3.5 phi by the study of the mean size of selected gravel samples measured in sawn slabs. The resulting regression line has a slope of one and an intercept of 0.4 phi and is close to that found for the sands. Grain size in grain mount is also closely related to sieve and thin section size, and a preliminary study of pebble size measured from photographs suggests that this may also be converted to an equivalent sieve size. On qualitative grounds the relationships between the various mean size statistics should involve the simple addition of a constant phi value. However the slopes of the regression equations found in the present work differ slightly from a slope of one. This difference is shown to represent a progressive shape change with size. For a constant b/a ratio of 0.73 or 0.70 conversion of thin section mean size (in phi units) to an equivalent sieve value should therefore be made by the simple addition of a 0.33 or 0.40 phi constant respectively.</p>

scholarly journals Empirical Determination of Sieve Size Statistics from Grain Measurement

2021 ◽  
Author(s):  
◽  
John Edward Adams
Keyword(s):  
Grain Size ◽  
Thin Section ◽  
Shape Change ◽  
Regression Line ◽  
Apparent Size ◽  
Regression Equations ◽  
Simple Addition ◽  
Sieve Size ◽  
Mean Size ◽  
Log Normal

<p>Relationships between sieve grain size and thin section grain size have been determined empirically from the study of 72 artificially created sendstone samples. Modern sands were sieved into size fractions, which were recombined in a log normal distribution to give samples with a range of means and standard deviations, but with similar individual grain properties. Sample splits of these were impregnated with resin, and the size distribution of grain long axes selected by point counter in thin section was compared with that found by sieving the remaining sample. This method attempts to minimise the effects of factors that influence apparent size in thin section. The results have been compared with those of (1958, 1962) who studied the same size relationships in 38 natural sandstones, e.g. This work: Sieve size from Folk = 1.078(thin section mean) + 0.200 phi graphical mean 1/3(Ø16+Ø50+Ø84) Friedman (1958): Sieve size mean from = 0.903(thin section mean) + 0.381 phi combined quartile measures Ø25, Ø50,Ø75 The regression coefficients differ from those of Friedman, probably because of the range of mean sizes investigated in the present work was twice as large (5.7 phi units vs. 2.6 phi units). The correlation coefficient relating sieve to thin section analysis decreases progressively, as Friedman found, from mean (0.992) to standard deviation (0.958), skewness (O.536), and kurtosis (0.249). The correlation for skewness and kurtosis is not significant. The size range was extended to -3.5 phi by the study of the mean size of selected gravel samples measured in sawn slabs. The resulting regression line has a slope of one and an intercept of 0.4 phi and is close to that found for the sands. Grain size in grain mount is also closely related to sieve and thin section size, and a preliminary study of pebble size measured from photographs suggests that this may also be converted to an equivalent sieve size. On qualitative grounds the relationships between the various mean size statistics should involve the simple addition of a constant phi value. However the slopes of the regression equations found in the present work differ slightly from a slope of one. This difference is shown to represent a progressive shape change with size. For a constant b/a ratio of 0.73 or 0.70 conversion of thin section mean size (in phi units) to an equivalent sieve value should therefore be made by the simple addition of a 0.33 or 0.40 phi constant respectively.</p>

scholarly journals Mudrock Microstructure: A Technique for Distinguishing between Deep-Water Fine-Grained Sediments

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 653
Author(s):  
Shereef Bankole ◽  
Dorrik Stow ◽  
Zeinab Smillie ◽  
Jim Buckman ◽  
Helen Lever
Keyword(s):  
Grain Size ◽  
Deep Water ◽  
Sedimentary Facies ◽  
X Ray Diffraction ◽  
Weak Current ◽  
Large Area ◽  
Fine Grained ◽  
Mean Size ◽  
The Mean ◽  
Water Facies

Distinguishing among deep-water sedimentary facies has been a difficult task. This is possibly due to the process continuum in deep water, in which sediments occur in complex associations. The lack of definite sedimentological features among the different facies between hemipelagites and contourites presented a great challenge. In this study, we present detailed mudrock characteristics of the three main deep-water facies based on sedimentological characteristics, laser diffraction granulometry, high-resolution, large area scanning electron microscopy (SEM), and the synchrotron X-ray diffraction technique. Our results show that the deep-water microstructure is mainly process controlled, and that the controlling factor on their grain size is much more complex than previously envisaged. Retarding current velocity, as well as the lower carrying capacity of the current, has an impact on the mean size and sorting for the contourite and turbidite facies, whereas hemipelagite grain size is impacted by the natural heterogeneity of the system caused by bioturbation. Based on the microfabric analysis, there is a disparate pattern observed among the sedimentary facies; turbidites are generally bedding parallel due to strong currents resulting in shear flow, contourites are random to semi-random as they are impacted by a weak current, while hemipelagites are random to oblique since they are impacted by bioturbation.

scholarly journals Relevance of processing parameters for grain growth of metal halide perovskites with nanoimprint

2021 ◽  
Vol 127 (9) ◽  
Author(s):  
Andre Mayer ◽  
Tobias Haeger ◽  
Manuel Runkel ◽  
Johannes Rond ◽  
Johannes Staabs ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Growth ◽  
Secondary Growth ◽  
Processing Parameters ◽  
Post Processing ◽  
Perovskite Layer ◽  
Processing Step ◽  
Similar Preparation ◽  
Materials Used ◽  
Log Normal

AbstractThe quality and the stability of devices prepared from polycrystalline layers of organic–inorganic perovskites highly depend on the grain sizes prevailing. Tuning of the grain size is either done during layer preparation or in a post-processing step. Our investigation refers to thermal imprint as the post-processing step to induce grain growth in perovskite layers, offering the additional benefit of providing a flat surface for multi-layer devices. The material studied is MAPbBr3; we investigate grain growth at a pressure of 100 bar and temperatures of up to 150 °C, a temperature range where the pressurized stamp is beneficial to avoid thermal degradation. Grain coarsening develops in a self-similar way, featuring a log-normal grain size distribution; categories like ‘normal’ or ‘secondary’ growth are less applicable as the layers feature a preferential orientation already before imprint-induced grain growth. The experiments are simulated with a capillary-based growth law; the respective parameters are determined experimentally, with an activation energy of Q ≈ 0.3 eV. It turns out that with imprint as well the main parameter relevant to grain growth is temperature; to induce grain growth in MAPbBr3 within a reasonable processing time a temperature of 120 °C and beyond is advised. An analysis of the mechanical situation during imprint indicates a dominance of thermal stress. The minimization of elastic energy and surface energy together favours the development of grains with (100)-orientation in MaPbBr3 layers. Furthermore, the experiments indicate that the purity of the materials used for layer preparation is a major factor to achieve large grains; however, a diligent and always similar preparation of the layer is equally important as it defines the pureness of the resulting perovskite layer, intimately connected with its capability to grow. The results are not only of interest to assess the potential of a layer with respect to grain growth when specific temperatures and times are chosen; they also help to rate the long-term stability of a layer under temperature loading, e.g. during the operation of a device.

scholarly journals Statistical characteristics for the type and length of deformation-induced cracks in columnar-grain ice

1997 ◽  
Vol 43 (144) ◽  
pp. 311-320 ◽  
Author(s):  
Lorne W. Gold
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Strain Rate ◽  
Relative Proportion ◽  
Constant Strain Rate ◽  
Statistical Characteristics ◽  
Columnar Grain ◽  
Log Normal ◽  
Almost All ◽  
Log Normal Distribution

AbstractObservations are reported on cracks formed during compressive, unidirectional, constant-strain-rate deformation of columnar-grain ice. The axis of hexagonal crystallographic symmetry of each grain tended to be in the plane perpendicular to the long direction of the grains and to have a random orientation in that plane. For stress applied perpendicular to the long direction of the grains, the deformation was practically two-dimensional. It was found that the relative proportion of grain-boundary cracks increased with increasing strain rate, decreasing temperature and, for strain rate greater than 7 × 10−5 s−1, with decreasing grain-size. Almost all the grain-boundary cracks had at least one edge at a triple point. For each test, the grain-boundary and transcrystalline crack lengths tended to have a log-normal distribution. The logarithmic mean crack length (LMCL) decreased with increasing strain rate, decreasing grain-size and decreasing temperature and tended to a constant value of 0.75 mm at 10°C. For grain-size of 3 mm or greater, the LMCL had a maximum at a strain rate of 10−5 to 10−6 S−1 at −10°C. The LMCLs and the relative proportion of grain-boundary cracks tended to be normally distributed for given load conditions.

scholarly journals Laboratory study of the properties of frazil ice particles and flocs in water of different salinities

2019 ◽  
Vol 13 (10) ◽  
pp. 2751-2769 ◽  
Author(s):  
Christopher C. Schneck ◽  
Tadros R. Ghobrial ◽  
Mark R. Loewen
Keyword(s):  
Growth Rate ◽  
High Resolution ◽  
Saline Water ◽  
Camera System ◽  
Average Growth ◽  
Frazil Ice ◽  
Ice Particles ◽  
Thermodynamic Conditions ◽  
Mean Size ◽  
Log Normal

Abstract. Measurements of the size and shape of frazil ice particles and flocs in saline water and of frazil ice flocs in freshwater are limited. This study consisted of a series of laboratory experiments producing frazil ice at salinities of 0 ‰, 15 ‰, 25 ‰ and 35 ‰ to address this lack of data. The experiments were conducted in a large tank in a cold room with bottom-mounted propellers to create turbulence. A high-resolution camera system was used to capture images of frazil ice particles and flocs passing through cross-polarizing lenses. The high-resolution images of the frazil ice were processed using a computer algorithm to differentiate particles from flocs and determine key properties including size, concentration and volume. The size and volume distributions of particles and flocs at all four salinities were found to fit log-normal distributions closely. The concentration, mean size, and standard deviation of flocs and particles were assessed at different times during the supercooling process to determine how these properties evolve with time. Comparisons were made to determine the effect of salinity on the properties of frazil ice particles and flocs. The overall mean size of frazil ice particles in saline water and freshwater was found to range between 0.52 and 0.45 mm, with particles sizes in freshwater ∼13 % larger than in saline water. However, qualitative observations showed that frazil ice particles in saline water tend to be more irregularly shaped. The overall mean size of flocs in freshwater was 2.57 mm compared to a mean size of 1.47 mm for flocs in saline water. The average growth rate of frazil particles was found to be 0.174, 0.070, 0.033, and 0.024 mm min−1 and the average floc growth rate was 0.408, 0.118, 0.089, and 0.072 mm min−1 for the 0 ‰, 15 ‰, 25 ‰, and 35 ‰, respectively. Estimates for the porosity of frazil ice flocs were made by equating the estimated volume of ice produced based on thermodynamic conditions to the estimated volume of ice determined from the digital images. The estimated porosities of frazil ice flocs were determined to be 0.86, 0.82, 0.8 and 0.75 for 0 ‰, 15 ‰, 25 ‰ and 35 ‰ saline water, respectively.

scholarly journals Characterization of glacial silt and clay using automated mineralogy

2019 ◽  
Vol 60 (80) ◽  
pp. 49-65
Author(s):  
Jeff W. Crompton ◽  
Gwenn E. Flowers ◽  
Brendan Dyck
Keyword(s):  
Grain Size ◽  
Size Composition ◽  
Rock Properties ◽  
Fine Grained ◽  
Rock Fragments ◽  
Grain Sizes ◽  
Automated Mineralogy ◽  
Log Normal ◽  
Discrete Populations

AbstractGlacial erosion produces vast quantities of fine-grained sediment that has a far-reaching impact on Earth surface processes. To gain a better understanding of the production of glacial silt and clay, we use automated mineralogy to quantify the microstructure and mineralogy of rock and sediment samples from 20 basins in the St. Elias Mountains, Yukon, Canada. Sediments were collected from proglacial streams, while rock samples were collected from ice marginal outcrops and fragmented using electrical pulse disaggregation. For both rock fragments and sediments, we observe a log-normal distribution of grain sizes and a sub-micrometer terminal grain size. We find that the abrasion of silt and clay results in both rounding and the exploitation of through-going fractures. The abundance of inter- versus intragranular fractures depends on mineralogy and size. Unlike the relatively larger grains, where crushing and abrasion are thought to exploit and produce discrete populations of grain sizes, the comminution of fines leads to a grain size, composition and rounding that is continuously distributed across size, and highly dependent on source-rock properties.

Tail Departure of Log-Normal Grain Size Distributions in Synthetic Three-Dimensional Microstructures

2011 ◽  
Vol 43 (8) ◽  
pp. 2810-2822 ◽  
Author(s):  
Joseph C. Tucker ◽  
Lisa H. Chan ◽  
Gregory S. Rohrer ◽  
Michael A. Groeber ◽  
Anthony D. Rollett
Keyword(s):  
Grain Size ◽  
Three Dimensional ◽  
Size Distributions ◽  
Grain Size Distributions ◽  
Log Normal

scholarly journals Comparative Study of Statistical Distributions in Electromigration-Induced Failures of Al/Cu Thin-Film Interconnects

1994 ◽  
Vol 16 (2) ◽  
pp. 119-126 ◽  
Author(s):  
M. I. Loupis ◽  
J. N. Avaritsiotis ◽  
G. D. Tziallas
Keyword(s):  
Thin Film ◽  
Grain Size ◽  
Extreme Value Distribution ◽  
Statistical Distributions ◽  
Post Processing ◽  
Failure Times ◽  
Life Data ◽  
Cu Thin Film ◽  
Log Normal ◽  
Log Normal Distribution

In electromigration failure studies, it is in general assumed that electromigration-induced failures may be adequately modelled by a log-normal distribution. Further to this, it has been argued that a lognormal distribution of failure times is indicative of electromigration mechanisms. We have combined post processing of existing life-data from Al/Cu + TiW bilayer interconnects with our own results from Al/Cu interconnects to show that the Log Extreme Value distribution is an equally good statistical model for electromigration failures, even in cases where grain size exceeds the linewidth. The significance of such a modelling is particularly apparent in electromigration failure rate prediction.

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