Large Number Of Grains Research Articles

Extreme Strain Fluctuations in Polycrystalline Materials

The stochastic structure of polycrystalline materials causes a high inhomogeneity of the kinematic and force fields in grains of materials and large fluctuations of these fields. The inhomogeneity and fluctuations are insignificant in some cases, but they become crucial in the study of various critical phenomena whose occurrence strongly depends on the type of material microstructure. Fluctuations mainly arise due to the elastic interaction of grains, which has a long-range effect. Therefore, it is necessary to account for the interaction of a large number of grains, which is difficult to do using conventional methods (direct computer modeling and others). In the present paper, inhomogeneous mesostrain fluctuations in grains of polycrystalline materials were estimated using a field-theoretical approach to a boundary-value problem of microheterogeneous material deformation. Particular attention is paid to the calculation of extreme fluctuations that are important for some critical phenomena, such as, e.g., crack initiation under gigacycle fatigue when the macrostress amplitude and the mean stresses in grains are much lower than the quantities included in any macroscopic damage or fatigue criteria. Phe maximum mesostrains in grains can exceed several times the macrostrains. Extreme fluctuations in a grain are generated in grain clusters of specific configuration. Phe applied approach makes it possible to predict patterns of such clusters. Extreme fluctuations in the bulk grains of a polycrystalline body are much higher than in the surface grains, due to which the behavior of the material surface layers and bulk volumes is different. Quantitative data are given for the case of uniaxial tension of polycrystalline zinc.

Assessment of the quality and safety of carpets with mycotoxicosis

Assessment of the quality and safety of carpets with mycotoxicosis

Reakcja odmian pszenicy jarej na zróżnicowany poziom intensywności technologii produkcji

W badaniach oceniono reakcję odmian pszenicy jarej na dwa zróżnicowane poziomy intensywności technologii uprawy. Doświadczenie przeprowadzono w latach 2013–2015 na polach Zakładu Doświadczalnego Oceny Odmian w Skołoszowie. Uzyskane wyniki badań wykazały, że intensywny poziom technologii produkcji powodował wzrost plonu ziarna pszenicy o 1,6 t·ha-1, w porównaniu do plonu uzyskanego w technologii średnio intensywnej. Wzrost plonu ziarna pszenicy uprawianej według technologii intensywnej w odniesieniu do technologii średnio intensywnej wynikał z większej liczby kłosów na jednostce powierzchni. Odmiany pszenicy jarej różniły się poziomem plonowania oraz wartością elementów składowych plonu. Największy plon ziarna uzyskała odmiana KWS Torridon, a najmniejszy Izera. Odmiana Izera, KWS Torridon i Tybalt uzyskały największą obsadę kłosów na jednostce powierzchni, z kolei odmiana Parabola uzyskała największą masę 1000 ziaren, a największą liczbę ziaren z kłosa uzyskała odmiana KWS Torridon.

Variability of the constituent elements of the productivity of maize hybrids of different ripeness groups under irrigation conditions

Purpose. To determine the correlation dependences of the constituent elements of the productivity of maize hybrids of different ripeness groups with grain producti­vity under irrigation conditions in the Southern Steppe of Ukraine. Methods. Field, laboratory, mathematical and statistical. Results. The article presents the results of studies to determine the correlation dependencies between the biometric features of the corn cob, in order to assess plant productivity. According to the number of rows per ear, hybrids of late ripening groups stood out – 17.7 pcs., medium late forms were statistically close to this – 16.8 pcs. The largest number of grains in a row was formed by hybrids of the middle-late group (FAO 400–490) 48.8 pcs. The highest grain weight from the cob wasfound in hybrids of the middle-late group – 312.5 g. It was shown that the number of rows has significant correlation with the diameter of the core and cob. The number of rows had a stable low directed effect on productivity. A significant correlation is fixed between the number of grains in a row and such signs as the length of the core and the length of the grained cob. Connection was high in all FAO groups. The mass of grains per cob is the main component of the structure of the corn crop. A close correlation of the mass of grains per cob was observed with the following signs: grain productivity, length of the core, length of the cob with grains, diameter of the cob, weight of 1000 seeds, grain yield. Conclusions. Under irrigation conditions the genotypic variability of the constituent elements of the maize hybrids productivity was revealed, which allows predicting the conduct of effective screening on specific characteristics according to ripeness groups.The revealed correlation dependences between quantitative signs of the cob structure and grain yield will allow to make a preliminary assessment of potential yield by factorial charac­teristics adapted to the conditions of irrigation of corn hybrids with FAO 180–600.

Extended granular micromechanics approach: a micromorphic theory of degree n

For many problems in science and engineering, it is necessary to describe the collective behavior of a very large number of grains. Complexity inherent in granular materials, whether due the variability of grain interactions or grain-scale morphological factors, requires modeling approaches that are both representative and tractable. In these cases, continuum modeling remains the most feasible approach; however, for such models to be representative, they must properly account for the granular nature of the material. The granular micromechanics approach has been shown to offer a way forward for linking the grain-scale behavior to the collective behavior of millions and billions of grains while keeping within the continuum framework. In this paper, an extended granular micromechanics approach is developed that leads to a micromorphic theory of degree n. This extended form aims at capturing the detailed grain-scale kinematics in disordered (mechanically or morphologically) granular media. To this end, additional continuum kinematic measures are introduced and related to the grain-pair relative motions. The need for enriched descriptions is justified through experimental measurements as well as results from simulations using discrete models. Stresses conjugate to the kinematic measures are then defined and related, through equivalence of deformation energy density, to forces conjugate to the measures of grain-pair relative motions. The kinetic energy density description for a continuum material point is also correspondingly enriched, and a variational approach is used to derive the governing equations of motion. By specifying a particular choice for degree n, abridged models of degrees 2 and 1 are derived, which are shown to further simplify to micro-polar or Cosserat-type and second-gradient models of granular materials.

Evaluation of the Superabsorbent Effect on the Yield and Some Growth Factors of Pisum sativum L. under Drought Stress Conditions.

Deficit irrigation is an optimum technique for producing products under drought stress conditions. The superabsorbent hydrogel is a hydrophilic polymer with cross-linked 3-D hydrophilic nets that are able to take up and keep noteworthy values of water and aquatic liquids. Recently published patents have provided significant information about the superabsorbent application in agriculture. The aim of this study was to investigate the superabsorbent effect on the yield and some of the growth factors of Pisum sativum L. under drought stress conditions. The experimental factors included: irrigation treatments at two levels of 100% and 75% water requirement by the plant. The second factor included the levels of superabsorbent application which included three levels of control treatment, potting soil with a weight percentage of 0.5 and 1. The third factor was the location of the superabsorbent application. According to the results, the largest root length value corresponded to I2S1U treatment plan, the largest root dry weight value corresponded to I1S2U treatment plan, the largest plant dry weight corresponded to I2S1U treatment plan, the largest grain dry weight corresponded to I2S1U treatment plan, the largest number of grains per pod corresponded to I2S2U treatment plan and the largest number of pods per plant corresponded to I2S1U treatment plan which were significant at 5% level. It was concluded that the presence of the superabsorbent at the lower end of the pot was effective in providing water and nutrients for the plant root.

PRODUCT CHARACTERISTICS OF TRITICUM PETROPAVLOVSKYI AND ITS SPONTANEOUS MACROMUTANTS

The studies were conducted on the experimental field of the FSBSI “Federal Russian Agricultural Research Center”, whose soils are ordinary blackearth (chernozem). 25 productive shoots of each sample were taken in their full ripeness, and, when the seeds reached standard humidity, there was performed a structural analysis in the laboratory. T. petropavlovskyi and spontaneous macromutant forms emerged from cultivation were used as the objects of study. In the process of a long-term cultivation of T. petropavlovskyi in the collection, there were identified numerous spontaneous macromutant forms of a specific nature. The paper presents the study results of the product characteristics of T.petropavlovskyi and spontaneous macromutant forms which are phenotypically close to T. spelta and soft-like T. aestivum and typical soft wheat T. aestivum. It has been established that product characteristics of speltoid macromutant wheat are significantly inferior to the original T. petropavlovskyi and macromutant soft wheat T. aestivum. Product features of soft-like macromutant T. aestivum is similar to the original T. petropavlovskyi, but has a smaller sprout weight and, correspondingly, lower grain productivity. The most promising variety for breeding process is the macromutant typical soft wheat T. aestivum, which forms a larger number of grains and, due to this, has an advantage in ‘kernel weight per head’ over all samples, including the initial form. The value of this macromutant form can also be determined by the high coefficient of specific productivity (Csp), which indicates a more efficient work of its vegetative organs. Consequently, the macromutant T. aestivum, which is phenomenally similar to the existing varieties of soft wheat, promises a high hybridization efficiency with the latter. Thus, the macromutant form of T. aestivum, developed on the basis of the T. petropavlovskyi genotype, is of some value as an initial material for breeding practice.

Methods and approaches to improving the design of flexible backing grinding tools

Grinding with flexible backing grinding tools, such as flap wheels and grinding belts, has found wide application at all stages from roughing to decorative surface finish. At the same time, the performance of traditional factory-built flap wheels and grinding belts in many respects do not meet the expectations of consumers. Among other reasons, this is due to the fact that the designs of flap wheels and grinding belts are based on traditional sandpaper. In turn, the sandpaper is made from abrasive mass which is not sorted by shape and not oriented relative to the backing plate surface. The described situation leads to the fact that a large number of grains does not participate in the cutting process, but on the contrary, have a negative impact on it, because the abrasive particles fall out of the bond, heat and deform the material to be ground without cutting it off. The approaches to improving the design of flexible backing grinding tools are discussed, the issues of their design and manufacture using the abrasive grains with controlled shape and orientation are revealed in the article. The data on the impact of the grain shape and orientation on the cutting ability of grinding belts are given.

Reconstruction of Grains in Polycrystalline Materials From Incomplete Data Using Laguerre Tessellations.

Far-field three-dimensional X-ray diffraction microscopy allows for quick measurement of the centers of mass and volumes of a large number of grains in a polycrystalline material, along with their crystal lattice orientations and internal stresses. However, the grain boundaries-and, therefore, individual grain shapes-are not observed directly. The present paper aims to overcome this shortcoming by reconstructing grain shapes based only on the incomplete morphological data described above. To this end, cross-entropy (CE) optimization is employed to find a Laguerre tessellation that minimizes the discrepancy between its centers of mass and cell sizes and those of the measured grain data. The proposed algorithm is highly parallel and is thus capable of handling many grains (>8,000). The validity and stability of the CE approach are verified on simulated and experimental datasets.

Size effect on plastic anisotropy in microscale deformation of metal foil

Metal foils are extensively used for manufacturing microparts with a high depth-to-thickness ratio by microforming processes. Since there are few grains participating in the deformation of metal foil, the mechanical response of each individual grain intensively affects the deformation behavior and the quality of the formed micropart, which leads to strong anisotropy in microforming. To clarify the size effect on material anisotropy and the impact of scale-dependent plastic anisotropy on the formability of metal foil, a series of tensile experiments and geometrically scaled-down deep-drawing tests of SUS304 foil with different thicknesses of 50–200 μm and grain sizes of 10.2–80.5 μm were performed. The experimental results indicate that the anisotropy of flow stress, yield tensile ratio (i.e., ratio of the yield strength to the tensile strength) and elongation at angles of 0°, 45° and 90° to the rolling direction is prominently enhanced with decreasing thickness and that the anisotropy generally shows a substantial sensitivity to grain size. In addition, the abnormally increased hardening rate of flow behavior for metal foil with few grains in thickness direction arises from the deformation-induced transformation from austenite to martensite. The Lankford values in different orientations, the planar anisotropy and normal anisotropy coefficients decrease with increasing grain size and decreasing foil thickness. The foil manifests strong plastic anisotropy when the grain size is comparable to the foil thickness due to the dominant response of individual grains in terms of crystal orientation, texture, size and shape at a low value of t/d ratio (i.e., the ratio of the thickness to the grain size). Furthermore, several macroscale yield criteria are adopted to characterize the anisotropic phenomenon in the multi-scaled deep drawing process. The results suggest that the Yld2000-2d criterion is more suitable than Hill’48 and Von Mises functions to predict the anisotropic behavior of metal foil with a large number of grains involved in microforming. However, the prediction precision is worsened with decreasing t/d ratio, and the use of Yld2000-2d becomes problematic when the foil thickness is of the same magnitude as grain size, which is closely linked to the interactive effects of grain size, foil thickness and crystallographic texture in microscale plastic deformation.

The study of productivity and elements of its structure of the winter soft wheat varieties sown after sunflower

At present new varieties and hybrids capable to produce high and stable grain yields are of great demand. One of the main requirements to which they must meet is the ability to withstand environmental factors that reduce their productivity. Sunflower is a severe forecrop that extremely dries the soil, and it in its turn affects the productivity. Therefore, testing and selection of varieties able to withstand unfavourable conditions is of great urgency. This paper presents the study results of productivity and elements of its structure of 18 winter soft wheat varieties. The studies were carried out in the fields of the FSBSI “ARC “Donskoy”. Sowing was carried out with a Wintersteiger Plotseed planter with 4–6 cm of seeding depth. The seeding rate was 550 germinating grains per 1 m². Registration plot was 10 m² with 4-time periodicity. The winter soft wheat variety “Don 107” was used as a standard. According to a complex of traits, there were identified the varieties “Krasa Dona”, “Lilit”, “Volnitsa”, “Lidiya”, sown after sunflower which are able to produce high yields (6.9–7.5 t / ha), large number of grains per ear (30.7–36.2 pcs.) and 1000-kernel weight (41.1–45.5 g). The analysis found out that the productivity of winter soft wheat varieties had an average positive correlation between the number of productive stems (r = 0.32±0.24) and 1000-kernel weight (r = 0.43±0.22). There was a weak positive correlation between productivity, the number of kernels per ear, kernel weight per ear (r = 0.25±0.24 and r = 0.21±0.24 respectively).

Modeling and Simulation of KWC-type Phase-field Model for Nucleation Phenomena Considering a Large Number of Grains

Modeling and Simulation of KWC-type Phase-field Model for Nucleation Phenomena Considering a Large Number of Grains

Analysis on driving factors of improvement of quality and efficiency and transformation development of grasslands and animal husbandry industry

During the past several decades, the traditional agriculture structure has been unsustainable since decrease in grain consumption and increase in animal food consumption, resulting in a large number of grain to be used as forage. Grasslands and animal husbandry will gradually become the agricultural mainstream and lead the agriculture to get out of dilemma. Therefore, the cropping structure should be adjusted timely because the lower productivity of grassland for animal husbandry that is far not satisfied for human needs. Understanding how to solve the problems of “three rural” and “three animal husbandry” is of high importance for facing the growing demands for food structure and the desire for ecological civilization. Although grasslands and animal husbandry has developed vibrantly and achieved some achievements, forage grass and livestock production are considerably low and the industrial capacity is insufficient, and facing enormous challenges. Certainly, the development potential of grass and animal husbandry is also huge due to fast growing market demand in China. Our analysis showed that developing “animal-husbandry development” model by relying on scientific and technological innovation, talent construction, social needs and national policy support, which grasslands and animal husbandry industry will rapidly transform and develop, is an effective way to promote the forage grass and livestock production in China. We also discussed the driven factors about improvement of quality and efficiency and transformation development of grasslands and animal husbandry industry, and proposed seven principles for the development of “animal-husbandry development” in China, including construction of high quality forage production system, breeding and promotion of improved varieties, ecological protection of natural grassland, exploring different regional development modes and optimizing the industrial development environment. Grass animal husbandry development has reached breaking point, must optimize the structure of the industrial for the combination of economic, ecological and social benefits the coordinated development of the green road. At the same time, modern industrial development modes should be introduced to reform the traditional prataculture and agricultural and achieve a sustainable developing stage. Moreover, the society has provided a good opportunity for the transformation and upgrading of grassland and animal husbandry by the construction of ecological engineering and the protection of national food security. These will help us to realize the improvement of efficiency and quality, increase industrial benefits and the industrialization level, finally explore a sustainable development way with effective output, safe production, resource conservation and environment-friendly.

Influence of the Strain History on TWIP Steel Deformation Mechanisms in the Deep-Drawing Process

A study of preferable deformation modes on strain path and strain level in a TWIP steel sheet was performed. Different strain paths were obtained by stretch forming of specimens with various shapes and tensile tests. TEM analysis was performed on samples cut from various locations in the deformed specimens, which had different strain paths and strain levels and the preferable deformation modes were identified. Stresses caused by various strain paths were considered and an analytical analysis performed to identify the preferable deformation modes for the case of single crystal. For a single crystal, in assumption of the absence of lattice rotation, the strain path and the level of accumulated equivalent strain define the preferable deformation mode. For a polycrystalline material, such analytical analysis is not possible due to the large number of grains and, therefore, numerical simulation was employed. For the polycrystalline material, the role of strain path diminishes due to the presence of a large number of grains with random orientations and the effect of accumulated strain becomes dominant. However, at small strains the strain path still defines the level of twinning activity. TEM analysis experimentally confirmed that various deformation modes lead to different deformation strengthening mechanisms.

Evaluation of different wheat cultivars under salinity stress

A field experiment was conducted to study the response of different 11 wheat (Triticum aestivum L.) cultivars under saline condition and by applying saline irrigation water during rabi 2016-17 at Krishi Vigyan Kendra, Sri Muktsar Sahib (Punjab). Experiment site was chosen with high salinity condition (EC=1.87 dS/m) to check the response of particular cultivars in these conditions. The field was only irrigated with tube well water having very high EC (4630 micro mhos/cm). Results showed that the grain yield was recorded higher in KH 65 (5648 kg/ha), KRL 210 (5440 kg/ha), KRL 386 (5290 kg/ha) and DBW 246 (5048 kg/ha) as compared to lower grain yield recorded with KRL 384 (4353 kg/ha), KRL 19 (4423 kg/ha), KRL 370 (4538 kg/ha), DBW 248 (4608 kg/ha),WH 1316 (4838 kg/ha), DBW 247 (4860 kg/ha) and KRL 377 (4895 kg/ha). The experimental site was slightly saline in nature, so the cultivar KH 65, KRL 210, KRL 386 and DBW 246 are very suitable for the area as these were less affected due to salinity. Grain yield among these varieties were higher due higher number of effective tiller per unit area and due to large number of grains per ear. Whereas, KH 65, KRL 377 and KRL 386 also produced significantly higher straw yield from WH 1316, DBW 248, DBW 247, KRL 210, KRL 384, DBW 246, KRL 370 and KRL 19.

Modeling and simulation of ultrasonic beam skewing in polycrystalline materials

Ultrasonic wave propagation through polycrystalline media results in scattering caused by the anisotropy of single grains and randomness in the orientation of the individual grains making up the polycrystal. Scattering leads to variation in phase velocity and beam skewing of elastic waves leading to a loss in energy of the forward propagating wave, significantly affecting the ability to perform material characterization, defect detection and sizing in structural components. The present work addresses the problem of beam skewing of ultrasonic longitudinal waves using FEM-based wave propagation studies in a simulated polycrystal. A well-established Voronoi tessellation algorithm is used to represent an equiaxed polycrystalline morphology. Numerical simulations are performed on beam skewing in both weak (Aluminum) and strong (Copper) anisotropic media as a function of beam launch angles. The effect of a small number of large grains and a large number of small grains on the beam quality is described. The effective refraction in polycrystals is quantified with respect to the corresponding reference isotropic media and the implications for various applications are discussed.

Single-grain dating of potassium-rich feldspar grains: Towards a global standardised growth curve for the post-IR IRSL signal

Abstract Potassium-rich feldspar (K-feldspar) grains were extracted from 28 sediment samples from sites in Asia, Europe and Africa and the dose response curves — or growth curves — were constructed from the post-infrared infrared stimulated luminescence (pIRIR) signals emitted by individual grains. The samples exhibit large between-grain variation in both pIRIR signal intensity and the shape of the corresponding growth curves; the latter can be largely explained as a result of measurement uncertainties, including counting statistics and instrumental irreproducibility. This between-grain variation can be reduced by applying a least-squares normalisation (LS-normalisation) procedure, which allows a common growth curve — or global standardised growth curve (gSGC) — to be established for individual K-feldspar grains from the range of samples investigated. Equivalent dose (De) values for single grains can be estimated using the fitting parameters of the gSGC, together with measurements of the natural signal (Ln), one regenerative-dose signal (Lx) and their corresponding test-dose signals (Tn, Tx). The De values obtained using the gSGC approach are consistent at 2σ with those obtained from the individual growth curves constructed for each of the grains. The establishment of a gSGC greatly reduces the time required to measure a large number of grains for old samples, and it also overcomes the problem of De underestimation that can occur using a full single-aliquot (or single-grain) regenerative-dose (SAR) procedure when a large number of grains are rejected due to issues of ‘saturation’. The construction of a gSGC may, therefore, potentially extend the dating range of pIRIR signals beyond the reliable limit of De estimation using the standard SAR method.

Prinos i komponente prinosa zrna tritikalea gajenog na zemljištu tipa pseudoglej

A field trial was conducted on an acid pseudogley soil during the 2011/12, 2012/13 and 2013/14 growing seasons to evaluate grain yield and its components in four triticale cultivars ('Favorit', 'Tango', 'Odisej' and 'KG-20'). The highest values of grain yield, 1,000-grain weight, number of grains per spike, spike length and plant height in all cultivars were obtained in the year characterised by moderate temperatures during grain filling and high amounts of rainfall in the second part of the growing season. 'Favorit' gave the highest grain yield, the largest number of grains per spike, the lowest 1,000-grain weight and the smallest plant height. The highest 1,000-grain weight and the lowest number of grains per spike were found in 'Tango'. 'KG-20' had the greatest plant height and the lowest average grain yield during the three experimental years, with the lowest grain yield achieved in the driest year, and the highest in the wettest year. 'Odisej' exhibited a high grain yield, fewer grains per spike, and the lowest grain weight per spike compared to the other cultivars.

Simulation of wave propagation in polycrystalline materials

The propagation and scattering of elastic waves within heterogeneous materials is of wide interest in seismology, medical ultrasound, and non-destructive evaluation. Accurate models of the behavior of the waves are important for the development of methods to characterize the materials using this information, as well as for the development of methods pursuing other information about the materials for which the attenuation and scattering are a nuisance to be minimized. Until recently, the leading models have been limited to analytical methods based on low-order scattering assumptions. However, it has now become possible to perform accurate three-dimensional Finite Element simulations, using spatial representation at grain scale, in significant sample volumes of large numbers of grains. Recent work by the authors has demonstrated that this approach can deliver attenuation and wave speed predictions that are good enough to enable evaluations of the features and approximations of the analytical models. Current work is addressing the use of this approach, in combination with analytical models, to investigate the physical phenomena of the scattering attenuation and wave speed dispersion, including the influences of materials symmetries and degree of anisotropy, and the effects of metal forming such as grain elongation.

Effects of Zirconium Ions Doping on the Structural and Thermochromic Properties of VO2 Thin Films

As an inorganic functional material, VO2 thin films are expected to be used for smart windows. However, these films are not conducive to practical applications when the phase transition temperature (Tc) of the VO2 is approximately 68°C, which is greater than room temperature. To decrease Tc, the effect of Zr4+ doping on the structure and properties of VO2 films were investigated. The films were prepared using a sol–gel process, spin-coating on quartz glasses, and annealing at 525°C in a tube furnace within a nitrogen atmosphere. The results demonstrate that these films have a highly preferential crystalline orientation on the substrate; however, the primary two x-ray diffraction pattern peaks shift slightly toward the small angle, and when 7 at.% Zr4+ was doped in the VO2 film, the deviation angle was 0.16°, and the crystallite size was approximately 98 nm. A large number of grains were found on the surface of the pure VO2 films, but all the Zr4+ doped films had a layered structure, and the thickness of the films was approximately 200 nm. The Tc of these films was characterized using differential scanning calorimetry, and the luminous and solar transmittance was characterized using a UV–Vis–NIR spectrophotometer, which demonstrated that the effect of Zr4+ doping decreased Tc by approximately 1°C per 1 at.% on average, and the Tc of the 7 at.% film was slightly greater than that of the 5 at.% film, the phase transition temperature of which was 61.4°C. The transmittance decreased as the doping concentration increased, and 1 at.% Zr4+ doping increased the luminous regulation efficiency (ΔT lum) and solar modulation efficiency (ΔT sol). The ΔT lum of the pure VO2 film and the 1 at.% Zr4+-doped VO2 films was 10.9% and 11.2%, and ΔT sol was 14.4 and 15.2%, respectively.