Grain Size Distribution Of Samples Research Articles

Wide temperature range magnetoresistance enhancement of La0.67Ca0.33MnO3: NiO nanocomposites

This paper reports the addition of NiO nanoparticles into the LCMO nanocomposites through a simplified methodology in the heat treatment process compared to the previous work. Structural analysis showed that LCMO and NiO co-existed in the samples without the formation of other phases and confirmed their composite structures. The grain size distribution of samples was observed to become narrower and left-skewed as the concentration of NiO nanoparticles increased. This indicates that the NiO nanoparticles were distributed near the grain boundaries or on the grain surfaces. The presence of La, Ca, Mn, O, and Ni was confirmed by EDX analysis, and no additional impurities were noticeable, which revealed that the composites here are chemically pure in the composition. Temperature dependence magnetisation measurement (100–300 K) revealed the occurrence of ferromagnetic to paramagnetic transition. The Curie temperature, TC recorded at 260 K for all samples. However, the metal–insulator transition temperature, TMI was found to decrease from 246 to 120 K as the NiO content increased. Magnetoresistance of composites was observed to enhance over a wide temperature range at 10 kOe. The findings of LCMO: NiO composites in this work can set up a new perspective and unlock its potential to be utilised in magnetic field sensor element functioning at a wide range of temperatures.

Suitability of gravel deposits in Kirkuk city for concrete & roads works

The aim of research to a study some Engineering properties, Mechanical abrasion (Loss Anglos) test and Californian bearing ratio (CBR), with some physical properties such as optimum water content and specific gravity tests for aggregate deposits in Kirkuk / Iraq . Six samples taken from (Chiman) and (Shurau) sits , three samples from each sit which represented (Bai Hassan Formation) from (Shurau) sit , and Quaternary deposits from (Chiman) sit to estimate its resistance to abrasion and friction of the outer surface for course aggregate to show the suitability of geotechnical qualification of road layers and concrete works. The physical geotechnical evaluation results grain size distribution for samples (1, 2, 3) are matching for class (A) with simple shift in fine sizes according designation[1], while the samples (4, 6) are matching with class (B), while sample (5) matching exactly class (A), through represented the result as a curves and matching with standard curves all samples gave well graded curves. A results of specific gravity (dry, wet) of coarse aggregate (gravel) for samples (1, 2, 3) reached at average (2.583, 2.6) respectively, while a results of samples (4, 5, 6) reached at average (2.607, 2.624), and results of specific gravity (dry, wet) of fine aggregate (sand) for samples (1, 2, 3) reached at average (2.56, 2.542) respectively, while a results of samples (4, 5, 6) reached at average (2.491, 2.511), all the results within of limits that allowable according on American designation[2] between (2.3 – 3.2) . The strength tests (California bearing ratio) shows suitability to qualification needs to road works for sub base layer , where the values are (36%), (35%) respectively. Durability geotechnical tests (loss Angeles) results shows the weight loss for samples (1,2,3) are (% 20.4 ,% 25 , % 22.7) respectively, while for samples (4, 5, 6) the result are (19.80%, 22.3%, 20.06%) respectively. The Soundness test results for coarse aggregate (gravel) are (1.236%) for sample (1) and (1.062%) for sample (4) ,while the Soundness test results for fine aggregate (sand) are (2.897%) for sample (1) and (2.717%) for sample (4), so all samples are suitable to use in roads & concrete works .

Genetic and Environmental Effects on Grain Size Uniformity in Winter Wheat

Grain size is an important yield component and also influences flour yield, seed vigor and early plantlet development. It is usually described by the weight (or mass) of thousand grains or average of dimensions of a sample, without paying attention to the variability of individual grains. However, variation in individual grain size is economically important for milling industry, because many small grains are lost during the cleaning process prior to milling and a high proportion of small grains is indicative of a poor flour yield. Also, when grains are sown for a new crop, grain mass variability increases the heterogeneity of germination and leads to non-uniform seedling emergence and crop establishment, often leading to decreased yield. We analyzed using the software ImageJ (http://imagej.nih.gov/ij/) individual grain size distributions of samples 80 to 120 individual grains each, harvested from yield trials at NARDI Fundulea Romania with 13 cultivars grown on four management variants, during two years. Individual grain projected area, as a proxy of grain size, ranged from 8.18 to 29.06 mm2, and for most cultivars minimum values of individual grain projected area were less than half of maximum values. On average over all management variants and years, coefficients of variation (s%) varied from less than 14% in cultivars Bezostaya 1, Glosa and Pajura to more than 15.5% in cultivars Adelina and Litera. ANOVA for the coefficients of variation of grain projection areas showed that the main source of variation was the effect of cultivars, which was significant when tested both against the Error and the interaction Cultivars*Years. The effect of the four studied managements was significant when tested against the Error, but not when tested against the interaction with Years, suggesting that the managements did not have the same effect in the two years of study. The large differences between cultivars found in our study provide opportunities in breeding for higher grain uniformity.

Surface and subsurface characterisation of salt pans expressing polygonal patterns

Abstract. The data set described here contains information about the surface, subsurface, and environmental conditions of salt pans that express polygonal patterns in their surface salt crust (Lasser et al., 2020b; https://doi.org/10.5880/fidgeo.2020.037). Information stems from 5 field sites at Badwater Basin and 21 field sites at Owens Lake – both in central California. All data were recorded during two field campaigns from between November and December 2016 and in January 2018. Crust surfaces, including the mean diameter and fluctuations in the height of the polygonal patterns, were characterised by a terrestrial laser scanner (TLS). The data contain the resulting three-dimensional point clouds that describe these surfaces. The subsurface is characterised by grain size distributions of samples taken from depths between 5 and 100 cm below the salt crust and measured with a laser particle size analyser. Subsurface salinity profiles were recorded, and the groundwater density was also measured. Additionally, the salts present in the crust and pore water were analysed to determine their composition. To characterise the environmental conditions at Owens Lake, including the differences between nearby crust features, records were made of the temperature and relative humidity during 1 week in November 2016. The field sites are characterised by images showing the general context of each site, such as pictures of selected salt polygons, including any which were sampled, a typical core from each site at which core samples were taken, and close-ups of the salt crust morphology. Finally, two videos of salt crust growth over the course of spring 2018 and reconstructed from time lapse images are included.

Grain-size evidence for the transport pathway of the Xiashu loess in northern subtropical China and its linkage with fluvial systems

Abstract Knowledge of dust sources is crucial for understanding the aeolian system of the Xiashu loess which is distributed in the middle and lower reaches of the Yangtze River and in the Huai River region, and provides a unique long-term record of the environmental evolution of the humid subtropical region of East Asia. The debate on the dust source of the Xiashu loess arises partly from the lack of spatial information on its source signatures. In this study, we investigated spatial changes in the grain-size distributions of samples from 20 Xiashu and 6 Chinese Loess Plateau (CLP) loess sections of the Last Glacial period. The aims were to determine the genetic relationship between the Xiashu and the CLP loess, and to determine the transport pathway of the Xiashu loess. The grain-size data reveal that the trends in fining and sorting of the Xiashu loess do not conform to its being an extension of the CLP loess. This conflicts with the early view that the Xiashu loess represents a southward extension of the CLP loess. The southward-fining trend indicates that the Xiashu loess was mainly transported from north-to-south, and that the prevailing aeolian transport agent is the East Asian winter monsoon. We also examined present and published records of the transport pathway of the Xiashu loess and concluded that the deposits are mainly linked to the adjacent dessicated fluvial system of the Huai River. Thus, the Xiashu loess is mainly a repository of information on the evolution of this adjacent fluvial system.

Characteristics of grain size distribution and the shear strength analysis of Chenjiaba long runout coseismic landslide

Study on the grain size distribution characteristics and the frictional strength behavior of the slide deposits are helpful to disclose the landslide runout process and understand the mechanism of a long runout landslide. We performed grain size distribution analysis on samples collected from Chenjiaba landslide induced by Wenchuan earthquake. The grain size distribution of samples from the landslide sections quantitatively depicts a gradual coarsening upward grading from shear zone to the top section. Then a multistage - multiphase ring shearing approach was used to determine a comparative shear strength behavior of samples from each landslide section. In this method, a sample was sheared continuously for large displacement and fast rate on different normal stress conditions. The multiphase shear mode with a maximum of 105 mm/min rate has allowed observing the qualitative change and patterns of the frictional resistance behaviors of soils under different normal stresses. The results of coefficient of friction values under multiphase shear mode have shown substantial post peak shear weakening behaviors after large shear displacement that can be narrated with long runout processes. The shear strength test results indicate that the shear zone samples have developed higher friction angle values compared to overlying section samples, on the last phase of shear process, which may be very important to understand the braking mechanism of a long runout landslide.

Production of environmentally friendly cements using synthetic zeolite catalyst as the pozzolanic material

This study aimed at investigating the effect of addition of varying proportions of synthetic zeolite catalyst on the performance of produced cement and subsequently on the reduction of clinker content and the amount of CO2 emitted to the atmosphere. Mechanical and physical properties represented by compressive strength, fineness, and setting time of five zeolite-blended cement clinker specimens prepared using different proportions (1–10% by weight) of synthetic zeolite catalyst were examined. In addition, reference samples (synthetic zeolite-free) were considered to benchmark synthetic zeolite-added samples. Compressive strength and setting time tests were conducted for 2, 7, and 28 days of curing to identify mechanical behavior of the cement because of introducing synthetic zeolite. Crystal structure, chemical composition, and grain size distribution of samples in micro-areas were also characterized using scanning electron microscopy, energy-dispersive spectrometry, and X-ray diffraction analyses. Observations made in this study indicated that optimum proportions of synthetic zeolite could be introduced up to an upper limit of 10% without causing adverse effects on the mechanical behavior, quality, and performance of the produced cement. From the economic point of view, the findings of this study concluded that reduction of CO2 emission in cement-producing industry and saving in energy consumption could be implicitly achieved as a result of the replacement of the partial cement clinker with synthetic zeolite catalyst as the pozzolanic material. The results will be promising to use such additives in cement production to manufacture environmentally sustainable cement.

Heavy minerals in the late Eocene sandstone of Medicine Pole Hills, southwestern North Dakota

Late Eocene sandstone capping hills and small buttes in the Medicine Pole Hills in southwestern North Dakota has been correlated with the Chalky Buttes Member of the Chadron Formation. Heavy-mineral analysis was used to assess this correlation. Optical microscopy and chemical analysis using a scanning electron microscope/energy dispersive spectrometer (SEM/EDS) system were used to determine abundances and compositions of heavy minerals separated from 0.25–0.30 mm fractions of nine samples from seven depositional units (353–602 grains per sample). The 0.063–0.125 mm fraction was also studied for one of these samples. Samples ranged from coarse- to medium- to fine-grained poorly consolidated sandstone. Total heavy mineral recovery (0.4–14.1%) generally corresponded with the grain-size distribution of samples, with higher recoveries in coarser samples. Opaque grains (ferruginous aggregates, Fe-Ti oxides, and leucoxene) comprised 0.8–15.6 percent of heavy mineral grains. Non-opaque grains were dominated by amphibole (24.4–52.2%) and epidote-clinozoisite (10.6–38.1%), with variable diopside (0–51.1%). Generally less abundant minerals included garnet, apatite (bone fragments), biotite, and muscovite. One sample was biotite-rich (36.5%). Chemical compositions of heavy minerals showed no significant stratigraphic variations, suggesting the nature of the sources did not vary. Diopside, biotite, and approximately 1/3 of the amphibole grains were interpreted as derived from Tertiary volcanic sources. The majority of the amphibole grains (tremolite and blue-green hornblende), epidote, and garnet were derived from Precambrian metamorphic sources. The relative contribution of volcanic sources was variable (19–64%), being highest in those samples with more diopside and (with the exception of the biotite-rich sample) highest in those samples with higher overall heavy-mineral abundances. Individual heavy-mineral abundances also correlated fairly well with grain size. Overall, variations in heavy minerals were explained by variable volcanic source contributions and variations in grain-size distributions of the samples. Despite the variability found, cluster analysis showed that the samples from Medicine Pole Hills were consistently different than the generally much more stable heavy-mineral assemblages found in the Chalky Buttes Member. They were also consistently different when volcanic heavy minerals were ignored. The differences could not be explained by variable volcanic contributions, grain-size effects, and/or differences in heavy mineral stabilities alone. They require differences in provenance, suggesting that the sandstone of Medicine Pole Hills should not be correlated with the Chalky Buttes Member, or, at the very least, it should be considered a distinct facies of the Chalky Buttes Member.

Effects Of Drying Techniques On Grain-Size Analyses of Fine-Grained Sediment

Abstract To assess the effects of drying on subsequent grain-size analyses, a variety of drying approaches, including drying in ambient air, oven drying, and freeze drying, were applied to sediment collected from modern fluvial, lacustrine, and paludal settings, containing a wide range of clay-size fraction (16–61%). Samples were subsequently rehydrated and subjected to grain-size analysis in a laser particle-size analyzer, and histograms compared with those from control samples never subjected to drying. Results indicate that drying techniques induced no effect on grain-size distribution for samples containing 39% clay-size material, only freeze drying produced reproducible results statistically identical to the control samples.

Controlling of the polymorphic phase transition on lead-free piezoelectric Li0.08(Na0.52+xK0.48)0.92NbO3 ceramics

Abstract The polymorphic phase transition (PPT) from tetragonal to orthorhombic symmetry was tailored in lead-free piezoelectric ceramics Li 0.08 (Na 0.52+ x K 0.48 ) 0.92 NbO 3 (LN 0.52+ x KN) by controlling excess Na content, which is opposite to the usually reported orthorhombic–tetragonal phase transition. The grain growth was accelerated by adding excess Na, resulting in an increased grain size from 2–3 μm to 7–8 μm and a bimodal grain size distribution for samples x =0.015–0.04. The optimized piezoelectric properties with, i.e. d 33 =226 pC/N and k p =36.8% were obtained in sample x =0.04 due to the PPT effect. The corresponding T C , P r , and E r were 468 °C, 25.5 μC/cm 2 and 1.20 kV/mm, respectively.

An investigation of aspects of mine waste from a kyanite mine, Central Virginia, USA

Kyanite Mining Corporation, located in Dillwyn, Virginia has been in operation for over 50 years and their local operation is the largest kyanite mine in the world. As part of the processing at this location, a magnetic separate is generated and a minimum estimation of 3.57 million tons of waste has accumulated. Currently no use for the magnetic separate has been identified. We investigated eight representative samples of the magnetic mine waste which varied in color from a dark tan to black, to determine if the waste could be recycled as an ore or could be used as an environmental media. Mineralogical investigations indicate the composition of the magnetic mine waste is dominated by magnetite, kyanite, lesser amounts of hematite and charcoal. Magnetite occurs as fine grained crystals and as inclusions in kyanite. Hematite occurs largely as botryoidal textures, as discrete grains, and as coatings on kyanite grains. Fe-oxide spheres ranging in diameter from approximately 5–100 µm are common and may compose up to 10% in some samples. Titanium dioxide was rarely observed as coatings on silicate mineral grains. Energy dispersive spectroscopy analysis on magnetite crystals indicates they have end-member compositions. Bulk property investigations indicate that grain size distributions of samples are primarily unimodal with 20–40% of material being between 0.600 and 0.250 mm. Hydraulic conductivity values of samples investigated vary between 0.0036 and 0.0077 cm/s and are broadly consistent with those expected of sands with similar grain size distributions. In addition to the magnetic waste stream a light blue, water soluble, amorphous Cu sulfate occurs as a coating on surfaces of boulders. The coating is composed of rounded interlocking particles 5–60 μm in diameter. This material is of some environmental concern for freshwater invertebrates, but can be managed using sorption media. Hyperspectral data were gathered of the magnetic separate, kyanite ore samples, and the light blue Cu sulfate. The signatures of the kyanite ore, the blue mineral coating, and a mixture of the two provide spectral fingerprints that an imaging spectrometer could exploit for rapid detection and subsequent environmental monitoring.

Determination of grain size by XRD profile analysis and TEM counting in nano-structured Cu

In this work, a serial of pure copper sample with different grain sizes from nano- to micro-scale were prepared by sparkle plasma sintering (SPS) and following anneal treatment at 873 K and 1073 K, respectively. The grain size distributions of these samples were determined by both X-ray diffraction (XRD) profile analysis and transmission electronic microscope (TEM) micrograph counting. Although these two methods give similar distributions of grain size in the case of as-SPS sample with nano-scale grain size (around 10 nm), there are apparent discrepancies between the grain size distributions of the annealed samples obtained from XRD and TEM, especially for the sample annealed at 1073 K after SPS with micro-scale grain size (around 2 μm), which TEM counting provides much higher values of grain sizes than XRD analysis does. It indicates that for large grain-sized material, XRD analysis lost its validity for determination of grain size. It might be due to some small sized substructures possibly existed in even annealed (large grain-sized) samples, whereas there is no substructures in as-SPS (nanocrystalline) sample. Moreover, it has been found that the effective outer cut-off radius R e derived from XRD analysis coincides with the grain sizes given by TEM counting. The potential relationship between grain size and R e was discussed in the present work. These results might provide some new hints for deeper understanding of the physical meaning of XRD analysis and the parameters derived.

Sediment trend analysis of the hylebos waterway: Implications for liability allocations

Sediment trend analysis of the hylebos waterway: Implications for liability allocations

Using Grain Size Analysis as the Basis for a Research Project in an Undergraduate Sedimentology Course

Multi-week, research style projects within the context of a one-semester undergraduate course provide scope to explore topics in depth and build student skills. I developed a research-style project for an undergraduate sedimentology course using grain size analysis of sediments that combines developing field and laboratory skills, improving writing ability, exploring statistical techniques and encouraging critical thinking. The project asks students to consider the hypothesis that the grain size distribution of sediment samples can be successfully used as fingerprints to identify sediment transport processes and depositional environments. To do this groups of students work together collecting sediment from beach environments, analyzing the grain size distribution of these samples and use statistical analyses such as histograms and log-probability graphs to help interpret their data. The use of log-probability graphs, which are a somewhat controversial technique in sediment grain size analysis, is chosen to introduce students to contentious issues in scientific research and to encourage critical thinking. Success of the project is dependent on providing students with sufficient time and feedback and to re-write reports, analyze data and contribute to classroom presentations and discussions. Development of such projects requires thoughtful selection of a topic that will meet desired pedagogical objectives and careful structure so that time is managed effectively.

Measurements of spectral induced polarization for environmental purposes

Hydraulic permeability is one of the most important parameters for the evaluation of sediments relevant to environmental and hydrogeological problems. Up to now, permeability could be determined only by time-consuming and expensive methods like pumping tests or sampling and laboratory investigations. The results are confined to few locations, and they depend on the scale of the investigation method. Measurements on rock samples in a laboratory can differ significantly from well test results. Geophysical measurements are performed on different scales from high resolution measurements in boreholes up to large-scale soundings. Variations in permeability are mainly caused by varying grain size and by changes in porosity. A decrease of average grain diameter results in an increasing internal surface area. Petrophysical investigations have shown a reliable correlation between the imaginary part of electrical conductivity and the porespace-related internal surface. The formation resistivity factor, which is related to porosity, can be determined by geoelectrical measurements if the electrical conductivity of the pore fluid is known. The internal surface area and the formation factor are the only two parameters used by a Kozeny-Carman-like equation to evaluate the permeability or hydraulic conductivity for the investigated representative volume. Complex electrical conductivity is determined by measurements of induced polarization in the frequency domain. Frequencies below 10 Hz are used to avoid electromagnetic coupling. The permeability values determined by electrical measurements in boreholes can well be compared with those derived from the grain size distribution of samples. The same algorithm can be applied to evaluate the hydraulic conductivity of subsurface layers by complex resistivity soundings. The high sensitivity of the imaginary conductivity component to changes at the internal surface may be used as an indicator for contaminations.

Grain-size distribution in deforming subglacial tills: Role of grain fracture

Research Article| January 01, 1995 Grain-size distribution in deforming subglacial tills: Role of grain fracture Roger LeB. Hooke; Roger LeB. Hooke 1Department of Geology and Geophysics, University of Minnesota, Minneapolis, Minnesota 55455 Search for other works by this author on: GSW Google Scholar Neal R. Iverson Neal R. Iverson 1Department of Geology and Geophysics, University of Minnesota, Minneapolis, Minnesota 55455 Search for other works by this author on: GSW Google Scholar Geology (1995) 23 (1): 57–60. https://doi.org/10.1130/0091-7613(1995)023<0057:GSDIDS>2.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Roger LeB. Hooke, Neal R. Iverson; Grain-size distribution in deforming subglacial tills: Role of grain fracture. Geology 1995;; 23 (1): 57–60. doi: https://doi.org/10.1130/0091-7613(1995)023<0057:GSDIDS>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract New ways of looking at grain-size distributions may yield insights into sedimentary processes or environments. For example, during shearing of a granular material, alignments of grains, or bridges, develop with orientations such that compressive forces parallel to these alignments support most of the applied shear stress. If deformation is due to failure of such bridges by fracture, rather than by, say, dilation, the grain-size distribution will tend toward one that provides the maximum support for the grains. This size distribution is fractal and has a fractal dimension of 2.6. We analyzed the grain-size distribution of three deforming tills collected from beneath modern glaciers. The size distributions are fractal, and the mean fractal dimension is ∼2.9, suggesting an excess of fines. For comparison, grain-size distributions of samples from some other common sedimentary environments were also analyzed. Samples of dune sand and of glacial outwash were not fractal, but a debris-flow sample was, and had a fractal dimension of 2.8. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

VSA: a new fast size analysis technique for low sample weight based on Stokes' settling velocity

A new technique, VSA, provides a rapid, accurate, and precise method of determining the grain-size distribution of low weight samples. Its name, VSA, stands for volume size analysis. The apparatus is inexpensive and the proposed system can analyze four samples simultaneously in 85 min when used down to 0.45 μm size. The results are provided in sedimentation diameters. A set of equations, which discretely define the increasing volume of a homogeneous sediment sample settling in an enclosed volume of water, is solved to adequately approximate the continuous distribution. The final distribution is in terms of weight percent when bulk densities of discrete settled volumes are calculated. This additional calculation has only a marginal effect on the grain-size distribution of samples having means greater than 3 μm.VSA was compared with the pipette method and found to produce "statistically identical" size distributions.

Modes of turbidite deposition deduced from grain-size analyses

SummaryValues of quartile deviations (QDa) and medians (Mdmm) have been calculated from over 400 grain-size distributions of modern and ancient turbidites. Each QDa–Md pair is plotted on double-log paper to establish any distinctive trends. The QDa–Md analysis of modern turbidites reveals a steep gradient trend derived from the grain-size distributions of submarine canyon and delta fan sediments, and a shallow gradient trend derived from the grain-size distributions of samples from oceanic bottoms and nepheloid water layers. The QDa–Md analysis of ancient turbidites reveals two trends, but these do not coincide with their modern counterparts. The steeper gradient trend is related to distal and proximal turbidites, while the shallow trend is related to fluxoturbidites. The disparity between the ancient and modern QDa–Md analyses is caused by textural modifications of turbidites by diagenetic disintegration of unstable minerals. The alteration products are incorporated subsequently in the matrix. The diagenetic effects on the positions of the QDa–Md plots are demonstrated theoretically by computing the textural alteration of six modern turbidites by assuming that they will lose 20%, and then 40%, of their sand-sized particles to the matrix. By working in reverse the QDa–Md plots of ancient turbidites can be ‘restored’ to their diagenetically unaltered positions. Their restored positions correspond to the QDa–Md trends of modern turbidites.