Origin Of Grains Research Articles

How Important Are Genetic Diversity and Cultivar Uniformity in Wheat? The Case of Gliadins.

Improvements in self-pollinated crops rely on crosses between different genotypes. It has been suggested that the repeated use of "the best" genotypes may lead to the restriction of the genetic diversity of the crop. In wheat, the analysis of gliadin (storage protein) polymorphism has provided evidence that genetic diversity was high and stable throughout the 20th century. Moreover, a worldwide analysis of gliadin polymorphism shows that genetic diversity is structured spatially across countries and their regions. Therefore, the analysis of gliadin genotypes in a given grain sample can provide reliable information about the origin of grains in this sample. An unexpected finding is that many registered common wheat cultivars are genetically non-uniform and composed of authentic biotypes (genotypically related lines originated from the initial cross) in spite of current crop-registration rules that include a strict demand for each new cultivar to be genetically uniform (DUS rules). In summary, the results suggest that each cultivar is the fruit of joint effects of a breeder and of a region's environmental factors. We believe this finding will not be restricted to wheat and suggest there may be a need to re-evaluate relevant rules of cultivar registration for crop species in general.

A novel microwall sliding test uncovering the origin of grain refined tribolayers

The tribology induced microstructure determines the tribological properties of metals. Yet the complex interaction of multiple microcontacts makes it impossible to decouple the fundamental plastic mechanisms. Single nano-/microasperity sliding tests allow to separate the microcontacts and to study the origins of plastic evolution during the initial stages of wear. However, the fundamental formation mechanisms of the sliding induced grain refinement are still largely unknown. In this work, we pre-remove material around the wear track and produce microwalls, which simplify the stress state and allow to directly inspect the contact zone. After sliding on the microwalls, a misorientation jump forms in the crystal orientation below the wear track. The crystallographic misorientation reaches 30° in some configurations, resulting in the formation of large angle grain boundaries. The misorientation jump formation depends on the grain orientation, wear direction and on twin boundaries in its path. We unravel the grain formation mechanism via slip-step and dislocation analysis and address dislocation arrangements at the grain boundary. This novel microwall sliding test has a potential to better understand the origins of microstructure modification in metals during the run-in stage of wear.

Volcanic Origin and Significance of Glauconite Grains in the Upper Cretaceous Austin Chalk Formation in the Balcones Igneous Province, South and Central Texas

Abundant glauconite grains occur in the upper Austin Chalk A and B1 units within the confines of the Balcones Igneous Province (BIP) in the area of the Maverick Basin and San Marcos Arch in Central to South Texas. Controversy exists as to whether the origin of the grains is related to sedimentary hardgrounds or to alteration of volcanic ash and lapilli. The Austin Chalk A and B1 units were deposited contemporaneously with active volcanism (i.e., BIP), and glauconite grains are closely associated with and limited to the area of the BIP. Abundant ash and lapilli are noted near volcanic mounds, where many of these grains are converted to vermiculite and glauconite. It is well established that the BIP pyroclastics underwent alteration in seawater soon after deposition. An unambiguous transition from vermiculite and glauconite-altered volcanic fragments to sand-size glauconite is clearly demonstrated by thin-section and scanning electron microscopy analysis. Grains of glauconite (highly altered ash) deposited away from volcanic mounds have the same origin as those near the mounds. The sand-size glauconite grains can retain internal outlines of gas vesicles and other volcanic microstructures. The misidentification of these volcanic grains as sedimentary-formed glauconite, and not as altered volcanic ash, can lead to misinterpretation of the geologic history and sequence stratigraphy of the upper Austin Chalk section.

Mineral and nutritional assessments of soybean, buckwheat, spelt, and maize grains grown conventionally and organically

The present work determined complete mineral profile of four different types of grains (spelt, soybean, maize, and buckwheat) grown under two growing systems – conventional and organic. The contents of 20 macro-, micro- and trace elements were analysed in the examined grains by inductively coupled plasma-optical emission spectrometry (ICP-OES). In most samples, nine elements were present in concentrations higher than 10 mg/kg. The remaining elements were present at lower concentrations or in traces or not detected in certain samples. Aluminium and arsenic, as two toxic elements, were detected only in organic buckwheat grains. Based on the obtained results for the mineral contents, a nutritive assessment of the quality of grains of spelt, soybean, maize, and buckwheat were made. Results of nutritional assessment showed that spelt, soybean, and buckwheat grains could potentially be good sources of several minerals for human diet. On the other hand, the presence of some toxic elements, such as cadmium and strontium, should be monitored. Results of principal component analysis (PCA) and hierarchical cluster analysis (HCA) shown that the mineral composition, to a much greater extent, depended on the botanical origin of grains as compared to the production system.

Illuminating past river incision, sediment source and pathways using luminescence signals of individual feldspar grains (Rangitikei River, New Zealand)

AbstractSingle‐grain post‐infrared infrared stimulated luminescence (SG‐pIRIR) of feldspar has recently been introduced as a method to date Quaternary deposits. The method is particularly appropriate for fluvial deposits that cannot be dated by more conventional quartz optically stimulated luminescence dating and that are heterogeneously bleached (i.e. where only part of the grains is exposed to sufficient light to remove the full luminescence signal). Besides age estimation, single grain equivalent dose (De) distributions also reflect the variable bleaching degree and origins of grains. Thereby, the SG‐pIRIR signal offers a valuable tool to reconstruct sediment pathways. This study builds upon these ideas and develops a dual aspect that combined river terrace dating and SG‐pIRIR sediment pathway reconstruction for fluvial deposits in terraces and modern river floodplain along the Rangitikei River (RR), New Zealand. We found that the RR last aggrading phase (17.4 ± 1.9 ka to 11.6 ± 1.5 ka) was followed by a first phase of fast incision related to knickpoint retreat followed by a steady incision and widening of the RR canyon. TheDedistribution of fluvial deposits varies accordingly, due in particular to variable input of bedrock particles with saturated pIRIR signal from landsliding of valley flanks. Our study illustrates that the SG‐pIRIR approach is well suited to date terraces and shows how SG‐pIRIRDedistributions provide proxies to reconstruct sediment sources and pathways.

Current understanding of the origin of equiaxed grains in pure metals during ultrasonic solidification and a comparison of grain formation processes with low frequency vibration, pulsed magnetic and electric-current pulse techniques

The formation of fine, non-dendritic equiaxed grains throughout a casting without the addition of refiners (i.e. independent of alloy chemistry), is made possible by using ultrasonic, magnetic or pulsed magnetic and electric current pulse techniques. The dominant mechanisms proposed for the grain refinement produced during the application of an external field are cavitation phenomena assisted nucleation or fragmentation of dendrites (ultrasonic field), wall crystals arising from the cold surface of the mould (electric current pulse, magnetic and pulsed magnetic fields). In all these cases fluid flow provides an additional contribution (e.g. reduced temperature gradients, growth rate and remelting of dendrites) to maintaining an equiaxed grain structure. The origin of equiaxed grains under an external field also depends on the casting conditions (volume and shape of casting) and the type of alloy other than the mechanisms specific to a particular technique. The current work aims to provide a detailed understanding of the various factors and mechanisms that influence the grain refinement achieved during the solidification of pure metals (magnesium and zinc) subjected to UltraSonic Treatment (UST). The role of the temperature range of UST application, time duration and an unpreheated sonotrode are examined with respect to the origin, evolution of equiaxed grain structure, morphology and the columnar to equiaxed transition. The origin of grains was analysed from three fundamental aspects that contribute to refinement (i) heterogeneous nucleation (ii) fragmentation of existing dendrites and (iii) grains produced from the colder surfaces (arising from mould walls or vibrating surfaces as wall crystals). A comparison of UST refinement with mechanical, low-frequency vibration, electric current pulse and magnetic field solidification of pure metals has also been provided to highlight the importance of the cold surfaces (sonotrode and mould wall) in influencing grain refinement.

Application of risk solver platform to improve soybean crushing profitability

The growing number of participants in the grain market shows just how globalized this sector is in Brazil nowadays. It is difficult to note how mergers and acquisitions between local companies as major tradings and funds have been acquiring part or even the totality of Brazilian companies, like the soybean crushing company “XYZ” that acquired some assets such as crushing plants in the state of Mato Grosso, located on the center-west region of Brazil and access to 2 port terminals to export the byproducts. This work contains data from January of 2014 to September of 2017 including prices of soybean and by products, freight rates, basis at the ports and operational costs. This information comes from different sources including government and private agencies and Thomson Reuters Eikon software. This information was used to build a model in Microsoft Excel and by using the Risk Solver Platform, a powerful statistic calculator tool, to find a solution to improve “XYZ” profitability. The results of the model suggest changes in the origin of grains, reducing the volume in some locations and increasing the volume originated in other locations. After running 2 different scenarios, “XYZ” profits was increased by 1.24 million of US dollars.

A Study on Ryukyu Dynasty's Documented Myths about Origin of Grains

A Study on Ryukyu Dynasty's Documented Myths about Origin of Grains

Computationally efficient approximate likelihood procedures for the Boolean model

The Boolean model is a simple nontrivial random closed set process. It consists of a Poisson point process (producing germs) coupled with an independent random shape process (grains). Origins of grains are translated to germs to produce an arrangement of overlapping (or interpenetrating) shapes. An accurate discrete approximation to the continuous Boolean model on the real line offers computationally efficient likelihood procedures including maximum-likelihood estimation and likelihood ratio tests. The discrete approximation allows covering probabilities to be calculated using recursive formulas, which approach continuous densities as the sampling rate increases. Inference for higher dimensional Boolean models can be handled by linear transects. Several 2D estimation examples demonstrate the efficacy of this method.

Local strain in interface: Origin of grain tilting in diamond (001)/silicon (001) heteroepitaxy

Diamond grain tilting, one of the central problems of diamond heteroepitaxy on silicon (001) surface, has been studied by means of atomic-force and high-resolution electron microscopic observations, and by theoretical simulation using the molecular-orbital method. It is shown that, due to interface mismatch-induced local lattice strain and three-dimensional stacking, diamond nucleation in small areas results naturally in grain tilting. For more perfect heteroepitaxy, nucleation with reduced silicon surface damage and over relatively large lateral domains is required.

Size Distribution of Grains Growing by Thermal Grain-Grain Collision

The time variation in the size distribution of dqst grains is. investigated for the case where the grains are in thermal motion under the impact of ambient gas molecules and they are growing by sticking in grain-grain collisions. The growth of grains in this manner may be expected to occur in .highly dense interstellar .clouds (or protostars) and, especially, in the primordial solar nebula. · · The growth equation for the grains is formulated and some features of its solutions are studied analytically. Furthermore, for some initial condition the equation is numerically solved with a result that the mass spectrum of the grains tends to have a peak and the peak mass itself increases continuously with time. Finally, the shap~ of the spectrum approaches that given by a similarity solution of the equation. The final spectrum has a shape such that with increasing mass it rapidly rises to a peak and for large mass it decreases nearly exponentially. The peak mass is 8.8 times smaller than the mean mass. The analysis of the origin and composition of interstellar dust grains has so . far been made by many people, mainly on the l,o,asis of . the optical properties of the grains known from studies of the visible, infrared and ultraviolet spectrum of light from distant stars. The origin of the grains is not yet clear, but it is generally believed that they are formed somewhere by the condensation of vapor molecules of graphites, silicates and ices at temperatures between 2,000 and 100°K. For the condensation to proceed, high gas density is favorable. As possible places of the grain formation which requires relatively low temperatures and high densities, we can consider the cool atmospheres of red supergiants, planetary nebulae, expanding shells of novae and supernovae and very dense interstellar clouds (see, for example, a ·recent article of Salpeter 1'). After the condensation of grains from the vapor phase has been completed in the objects mentioned above, the grains ~ill further grow by sticking in grain­ grain collisions. The growth of this. type may be expected to occur in objects of high gas densities such as Q.ense interstellar clouds and, especially, in a rotating gaseous disk of the primordial solar nebula as studied by Kusaka, Nakano and Hayashi. 2' The motion of a grain in a dense gas will be thermalized relatively easily by the collisions of ambient hydrogen molecules and helium atoms, unless the gas is in a state of violent turbulence. In this paper, we shall study the change in the size distribution of grains

Simultaneous observation of grain structure and orientation in oriented silicon steel

To determine the origin of grains having spurious orientations in otherwise well-oriented silicon steel, it is sometimes desirable to observe simultaneously the shape and distribution of grains having specific orientations in a large sample of a coarse-grained polycrystalline sheet. A technique related to optical goniometry and an optical device for making the desired observations are described in detail. Photographic records of such observations are presented and explained. This device and rapid technique can be used to depict the preferred orientation in large (and therefore, statistically significant) samples of coarse-grained polycrystalline material. Present methods, which involve the stereographic plotting of poles of many grains, whose orientations have been determined by as many Laue interpretations, could be supplanted. Resulting photographic records could be more widely and intuitively understood, particularly by less technically skilled observers, since interpretation does not require familiarity with pole figures or stereographic projection.

Tales concerning the Origin of Grains in the Insular Areas of Eastern and Southeastern Asia

Tales concerning the Origin of Grains in the Insular Areas of Eastern and Southeastern Asia

Med bragende flammer. Brændingskulturens metoder i fortid og nutid.

Med bragende flammer. Brændingskulturens metoder i fortid og nutid.