Large Number Of Grains Research Articles

Partitioning of 15N Applied at Reproductive Stages among Grains and in Grain Tissues of Rice Plants.

Hydroponically-grown rice (Oryza sativa L.) plants were pulse-labelled with 15N-ammonium sulphate at various stages of reproductive growth, and partitioning of 15N among grains or grain tissues were examined at full maturity for a better understanding of the ripening process of rice panicle, which consisted of a large number of grains. Labelled nitrogen applied before heading was equally distributed to all grains. 15N applied at heading or the milk-ripe stage was mainly distributed to the early developing grains located on the upper part of the panicle, while that administered at a later period of ripening was principally transported to the later developing grains on the basal part. Thus, the position of grains actively accumulating nitrogen moved down from the upper to the basal part of the panicle with ripening. Active incorporation of 15N into husk continued up to the milk-ripe stage. At the later stages of grain filling, 15N uptake in the embryo became lower than that in the endosperm, indicating the formation of embryo preceded the endosperm. 15N levels incorporated into the inner parts of the endosperm decreased earlier than the outer parts ; this suggested that the deposition of nitrogen in the endosperm was first completed at the central part then extended to the peripheral layer. Based on these results, it could be concluded that the increase in the source-sink ratio is not sufficient to improve grain filling in the rice plants. It is also very important to maintain the physiological activities of leaves and roots until the later stages of ripening when the inferior spikelets continue to accumulate materials.

Preparation and Characterization of Grain Boundary Josephson Junction from Amorphous Thin Film

To prepare the grain boundary Josephson junction, Y-Ba-Cu-O amorphous thin film was first etched into a bridge shape and then annealed at a high temperature, 990°C, to form grain boundaries. The bridge thus prepared showed clear Shapiro steps under the irradiation of microwaves at 4.2 K. Grains of the films sensitively varied their structures, sizes and electric properties with annealing temperature. The grains annealed at a lower temperature, 960°C, were as small as a few micrometers or less. Large grains appeared when the annealing temperature became higher, and the higher the annealing temperature, the greater the number of large grains, untill 990°C. The bridge of 5 µm in width that had grains over 10 µm in size exhibited a.c. Josephson effect, but the effect was not observed with the bridge which consisted of only small grains of a few µm.

Control of Grain Yield by Sink Capacity and Assimilate Supply in Various Rice (Oryza sativa) cultivars

SummaryThe objective of this study was to identify whether grain yield in four contrasting rice cultivars is limited by supply of assimilate to fill the grains or by sink capacity to accept the assimilate. Grain yield was limited mostly by sink capacity, with little variation in single grain weight among cultivars, but an old cultivar showed some ability to adjust single grain weight. Sink capacity was very sensitive to variation in assimilate supply immediately after anthesis. Reduction in assimilate supply in the anthesis to early grain filling period reduced filled grain percentage and grain yield, particularly in high yielding cultivars with a large number of grains per panicle.

Melhoramento do trigo: XXIV. Avaliação de novos genótipos no Estado de São Paulo

Compararam-se vinte e três linhagens de diversas origens e dois cultivares de trigo em ensaios tanto em condição de irrigação por aspersão como de sequeiro, analisando-se a produção de grãos, outros componentes da produção e resistência às doenças. Em casa de vegetação, estudou-se a resistência às misturas de raças prevalecentes dos agentes causais da ferrugem-do-colmo e da-folha e, em condições de laboratório, a tolerância ao alumínio, em soluções nutritivas. As linhagens IAC-243, IAC-187 e IAC-188, de porte baixo, resistentes ao acamamento e de ciclo médio, e a linhagem IAC-190, de porte médio, salientaram-se quanto à produção de grãos em condições de irrigação por aspersão. Em sequeiro, destacaram-se quanto à produtividade as linhagens IAC-188 e IAC-193, de porte baixo, resistentes ao acamamento e de ciclo precoce. A linhagem 17 mostrou resistência às três misturas de raças prevalecentes do agente causal da ferrugem-da-folha em estádio de plântula, imunidade a essa ferrugem em condições de campo (planta adulta), resistência às duas misturas de raças de ferrugem-do-colmo, moderada resistência ao oídio e menor grau de área infectada pelos patógenos causadores de manchas foliares. O cultivar Alondra-S-46 mostrou ser fonte genética do caráter espiga comprida; a linhagem IAC-182, de maior número de espiguetas por espiga; 'Anahuac', de maior número de grãos por espiga e por espigueta e as linhagens IAC-188 e 17, de grãos mais pesados. As linhagens 2, IAC-182, IAC-243, 7, IAC-186, IAC-187 e IAC-193 foram as mais tolerantes à toxicidade de alumínio.

Cellular automata models of granular flow.

Simple experiments demonstrate the importance of particle irregularity on the flow of granular materials. We introduce cellular automata to model these flows with rules that are derived from experiments. Automata that model nonspherical particles can reproduce a number of important features of the physical flows, including alignment of the particles, the formation of a complex channel region, the formation of defects in the body of the material, and the overall shape of the upper free surface of the material.

Abnormal grain growth in sintered Nd-Fe-B magnets

Abnormal grain growth was found in sintered Nd-Fe-B magnets which are made from powder milled after hydrogen decrepitation. The abnormal grain size in the magnets sintered at 1000 °C for 1.5 h was as large as 400 μm. The formation of abnormally large grains reduced the magnetic properties. As sintering temperature increased, the number of large grains increased and coercivity reduced. However, abnormal grain growth was rarely found when the magnets were fabricated without hydrogen decrepitation. A grain growth mechanism is discussed in relation to the effect of hydrogenation and sintering process.

Melhoramento do trigo: XXIII. Avaliação de linhagens na região do vale do Paranapanema, em Capão Bonito e em Tietê, em 1984-88

Compararam-se vinte e duas linhagens e três cultivares de trigo em seis ensaios, instalados na região do Vale do Paranapanema, em 1984-88, analisando-se os seguintes parâmetros: rendimento de grãos; altura das plantas; ciclo, em dias, da emergência ao florescimento; porcentagem de plantas acamadas; comprimento da espiga; número de grãos por espiga e por espigueta; número de espiguetas por espiga; peso de cem grãos; resistência à ferrugem-do-colmo e da-folha em condições de campo e de casa de vegetação; resistência ao oídio e às manchas foliares em condição de campo. Realizaram-se também mais dois ensaios: um em Tietê, em condição de boa fertilidade do solo, e outro em Capão Bonito, em solo ácido. Em laboratório, efetuaram-se estudos da tolerância ao alumínio em soluções nutritivas. Em condição de sequeiro, na região do Vale do Paranapanema e em solo ácido de Capão Bonito, sobressaiu, quanto à produção de grãos, a linhagem 19 (CNT-9 x BH-1146) = IAC-227, com ciclo e porte médio. Em Tietê, destacaram-se pela produtividade as linhagens de ciclo médio: 1 (Alondra-S-46 x IAC-5) = IAC-225, e 17 (Alondra-1 x IAC-5) = IAC-226, ambas de porte baixo, e 3 (Alondra-S-46 x C-3), de porte alto. A 21 (IAC-5 x Alondra-S-46) mostrou-se resistente às duas misturas de raças da ferrugem-do-colmo, à ferrugem-da-folha em condição de campo e às duas misturas de raças dessa ferrugem em condição de casa de vegetação, com resistência, em planta adulta, ao oídio, e com menor área foliar infectada pelos patógenos causadores de manchas foliares, constituindo fonte de resistência a essas doenças. As linhagens 6 (C-3 x Sonora-64) e 17 mostraram-se fontes genéticas do caráter espiga comprida; a 17, de maior número de espiguetas e de grãos por espiga; a 10 (Jupateco x IAC-13), de maior número de grãos por espigueta, e a 5 (Tobari-66 x BH-1146), de grãos mais pesados. As linhagens 7, 9, 13, 16, 17 e 19 e o 'BH-1146' exibiram tolerância a presença de 10 mg/litro de Al3+ na solução nutritiva.

Does Σ Control Intergranular Cracking in Ni3Al?

AbstractThe relation between intergranular fracture and grain boundary character was studied in Ni3Al using the electron backscattering pattern (EBSP) technique. Using specimens of small grain size, we are able to index the orientation of a large number of grains, thus improving the statistical quality of the data compared to previous results. Furthermore, we are able to characterize the boundary planes using the EBSP method because of the special specimen geometry used. It was found that Σ3 boundaries do have a substantially lower propensity for cracking as compared to other boundaries, but there is no correlation between grain boundary Σ value and the propensity for cracking for low Σ and low angle boundaries. These results are in general agreement with recent theoretical predictions of grain boundary structure.

Vasoactive intestinal peptide in the hypothalamohypophysial system of the mongolian gerbil

By use of the indirect peroxidase-antiperoxidase immunohistochemical technique the location of perikarya and fibers exhibiting vasoactive intestinal peptide (VIP)-like immunoreactivity was investigated in the hypothalamus and the posterior pituitary of the Mongolian gerbil (Meriones unguiculatus), because of the involvement of VIP in several neuroendocrine functions. In the hypothalamus, a large number of VIP-immunoreactive perikarya were seen in the ventromedial part of the suprachiasmatic nucleus. Few VIP-positive perikarya were present in the periventricular, paraventricular, and supraoptic nuclei and in the medial preoptic area close to the third ventricle. The perikarya in the paraventricular nucleus projected fibers in the direction of the median eminence. In the median eminence VIP-immunoreactive fibers were present especially in the external layer, concentrated in the perivascular spaces surrounding the portal vessels. Scattered VIP-immunoreactive fibers were also located in the internal layer of the median eminence as well as in the posterior pituitary lobe. In the latter, large VIP-positive Herring-like bodies were observed. With receptor autoradiography a large number of grains were demonstrated in the anterior pituitary lobe in contrast to the neural lobe. Many VIP-positive fibers and some perikarya were observed within the ependyma covering the rostroventral part of the third ventricle. Finally, fibers exhibiting VIP immunoreactivity were also seen in the organum vasculosum laminae terminalis (OVLT). These results support the concept that VIP is released into the portal vascular system and plays a role in the regulation of the activity of the anterior pituitary. In addition, VIP might be secreted into the cerebrospinal fluid of the third ventricle.

The relationship between microtexture and grain boundary parameters

The orientations of individuals grains in an Ni-based superalloy have been measured by a new electron back scattering technique. This micro texture analysis is applied in conjunction with a scanning electron microscope, enabling the orientations of large numbers of grains to be acquired in a short time. Also the data has been collected in a grain specific manner, so that the orientations of large grains (which are a common feature of the grain structure of this alloy) may be assessed separately to the orientations of small grains. Microtextural differences between the smalland large-grain data sets were apparent and were found to be a function of the distribution of the large grains. Furthermore, the grain texture was shown to have a significant effect on the grain misorientation texture. The proportion of boundaries very close to a coincident site lattice geometry was small, and this was interpreted in terms of the relationship between boundary solute supersaturation and boundary misfit.

Microfracture of polycrystals and the Bishop & Hill stress states

Tungsten wires develop during their forming process a pronounced fibre texture that causes anisotropic deformation of single grains. The aim of this work is to simulate the crystallographic texture and microstructure evolution that arises during wire drawing using two different texture models. A visco-plastic self-consistent model that allows simulations using a large number of grains is compared with a crystal plasticity finite element model that provides a more detailed insight into the wire’s microstructure. Texture predictions of both models are discussed and quantitatively compared with experimental texture measurements obtained by neutron diffraction. The developed fibre texture causes plane strain deformation of single grains, which induces grain curling. The prediction of grain curling is of importance because it allows studying the residual stresses that trigger splits, at the grain level.

DEFORESTATION, CANNABIS CULTIVATION AND SCHWINGMOOR FORMATION AT CORS LLYN (LLYN MIRE), CENTRAL WALES

SummaryPollen and macrofossil diagrams from the schwingmoor sediments of Llyn Mire are presented. Prior to the formation of the schwingmoor, Cannabis sativa was cultivated around Llyn lake, first to the east and later to the west of the basin. Despite Cannabis cultivation so close to Llyn, there is no evidence to suggest that the lake was used for retting purposes.A period of woodland clearance occurred immediately after the Cannabis cultivation and this process may have been responsible for the changes which led to schwingmoor formation in the basin. It is suggested that increased soil erosion into the lake, together with some eutrophication, encouraged the colonization of the lake surface by a floating mat of vegetation. The schwingmoor was formed in historic times by a floating carpet of such taxa as Carex rostrata, Sphagnum recurvum and Sphagnum section Subsecunda. The mat was initiated in the western part of the basin.The use made of Cannabis/Humulus pollen density as a marker horizon in these studies demanded that these pollen taxa should be adequately separated, and the large numbers of grains of this type present in the sediments permitted the employment of numerical methods based on pore protrusion, which are described here.

酸化物磁性材料におけるＤｕｐｌｅｘ構造 ＩＩ 各種フェライトにおける発生およびその粒成長

Some small fraction of large grains was observed in the microstructure of sintered ZnFe2O4, MnZnFe2O4, Fe3O4 (in N2) and MnFe2O4 (in air). This structure is sometimes called "duplex structure". As the sintering proceeded, the number of large grains increased to form the continuous structure of large grains, while the size of large grains did not increase remarkably. On the other hand, the duplex structure was not observed in the ferrites with the composition of NiFe2O4 and CoFe2O4, independent of prefiring and sintering conditions. However, when amounts of Fe2O3 were excess in the composition of the ferrites, duplex-like structures were observed. This structure was also formed in the CoFe2O4 containing platinum powder (Pt black) known as a redox catalyst. From these results, the duplex structures seem to be formed in such ferrites that are easy to vary their compositions or valencies at high temperatures. In addition, the growth of small grains was very slow during the formation of duplex structure. It was considered that the exaggerate grain growth was generated by the local activation of the stabilized grain boundaries, which was caused by the variation of compositions or valencies during the sintering.

The presence of vasoactive intestinal polypeptide (VIP)-like-immunoreactive nerve fibres and VIP-receptors in the pineal gland of the Mongolian gerbil (Meriones unguiculatus). An immunohistochemical and receptor-autoradiographic study.

By use of the indirect peroxidase-antiperoxidase immunohistochemical technique, nerve terminals exhibiting vasoactive intestinal polypeptide (VIP)-like-immunoreactivity were demonstrated in the pineal gland of the Mongolian gerbil (Meriones unguiculatus). Incubation of the superficial pineal gland of the gerbil with 60 pM of 125I-VIP showed that the gland exhibited saturation kinetics, and about 80% of the bound 125I-VIP could be displaced by adding a surplus of cold VIP. Incubation of unfixed, 0.1% and 4% paraformaldehyde-fixed cryostat sections of the gerbil forebrain with 125I-VIP also exhibited saturation kinetics, and displacement was possible by adding a surplus of the cold tracer. Receptor autoradiography on cryostat sections that had been incubated for 60 min with 125I-VIP showed a large number of grains over cortical areas, especially over the pyramidal layer of the hippocampus and the granular layer of the dentate gyrus. A prominent labelling of the pineal gland was also observed. The presence of VIP-like-immunoreactive nerve terminals and receptors for this molecule in the pineal gland of the Mongolian gerbil supports the biochemical studies demonstrating a stimulatory function of this molecule in the synthesis of melatonin.

Yield responses by modern wheat genotypes to phosphate fertilizer and their implications for breeding

The response to phosphate fertilizer by modern wheat genotypes was examined in the field under natural rainfall in three seasons. Models were developed which show that grain yield was positively correlated with biological yield and harvest index. In one of the seasons, which was relatively dry, shorter statured wheats gave higher yields at each level of applied phosphate. Higher levels of phosphate tended to offset the reduction in yield associated with late heading and the importance of biological yield on grain yield. The genotypes which produced the largest number of grains m-2 produced the highest yields. Implications for plant breeding programs are discussed.

Characterization of a Lignite Ash from the Metc Gasifier I. Mineralogy

AbstractUtilization or disposal of gasification ash requires detailed characterization of its chemistry and phase formation (mineralogy). A North Dakota lignite ash produced in the Morgantown Energy Technology Center (METC) gasifier has been studied in detail by x-ray diffraction and electron microprobe analysis. The ash was coarse (84% of grains larger than 1.0 mm) but a typical grain was composed of a dozen or more crystalline phases with dimensions on the micrometer scale as well as less abundant glass phases. Hard centimeter-size clinkers suggested partial melting followed by crystallization. Silicates (dicalcium silicates (C2S), merwinite, Ca-Na-silicate (CNS), quartz), aluminosilicates (melilite, nepheline, carnegieite), oxides (ferrite spinels, periclase, hematite), calcite and minor zeolites comprised the dominant mineralogy. Microprobe analyses were obtained for large numbers of grains of the C2S phases, CNS, merwinite, melilite, ferrite spinels and calcite. The remaining phases had crystal sizes too small for analysis. A model is proposed for the genesis of this ash based on the inorganic constituents of lignite and the gasifier operating conditions.

Structure of indium tin oxide electrodes on zirconia

A necessary condition for the preparation of smooth indium tin oxide (ITO) layers prepared by chemical vapour deposition is that the substrate is smooth. For the thinnest films of ITO on zirconia the layer is smooth, but pores were observed along the boundaries of the substrate grains. For layers thicker than 0.25 μm, small and large grains appear, and the sizes of both grow linearly with the layer thickness. On annealing the films in air the number of large grains increases. The difference between the large grains and the background is not chemical. The layers grown are polycrystalline, but there is a preferred direction.

Evaluation of Optical and X-Ray Techniques for Detecting Source-Rock-Controlled Variation in Detrital Potassium Feldspars

ABSTRACT Potassium (K-) feldspar grains from Little Pipestone Creek and its tributaries within the Boulder Batholith of southwest Montana have been analyzed in order to evaluate the effectiveness of optical and X-ray techniques of K-feldspar structural-state discrimination for the definition of detrital mineralogical provinces and the interpretation of provenance. Source-rock-controlled structural-state variations in the detrital K-feldspar in Little Pipestone Creek were detected by two methods: the optical determination of the percentage of cross-hatch (albite-pericline) twinning, and the (131)-(131) X-ray diffraction (XRD) determination of the obliquity of individual K-feldspar grains. The optical method is the more efficient; a much larger number of grains can be analyzed in a given period of time. However, the (131)-(131) XRD method has greater resolving power; each analysis reveals much more about the true structural state and mode of origin of the K-feldspar grain than does the mere presence or absence of twinning. The even more precise (060)-(204) XRD method for determining K-feldspar structural state was found to be ineffective in his application because of its much lower efficiency. Neither XRD method proved to be effective when applied to aggregate-grain samples. K-feldspar structural-state provinces within this small, Holocene sand body were most effectively delineated by the combination of the optical determination of the percentage of cross-hatch twinning and the (131)-(131) XRD characterization of the structural state of selected individual K-feldspar grains. In larger, ancient bodies, particularly in complex alluvial systems where the feldspars have been derived from a varied array of feldspathic parent rocks (e.g., by the unroofing of plutons and their associated volcanic piles) this combined optical and X-ray approach should be even more effective.

Determination of the quantitative phase composition of alite and belite in portland cement clinker by microphotometry

In the light of the growing technical interest in the phase constitution of alite and belite in portland cement clinker, an optical method for determining the quantitative phase composition has been proposed. The change in birefringence upon transition between the relevant phases (M 1 to M 3 for alite and α to α′ for belite) is utilized for this purpose. In the present method the birefringence change with temperature has been recorded by microphotometry as the corresponding change in the integrated light intensity from a large number of grains in the field of view.

Ultrasonic attenuation and microstructure in low-carbon steels

AbstractUltrasonic attenuation measurements up to a frequency of 30 MHz have been made on a low-carbon steel. The microstructure was controlled to produce a series of specimens with varying ferrite grain size. Analysis of the attenuation data was not possible using a simple Rayleigh scattering model and the mean grain size. It was concluded that the grain size distribution is an important factor in determining the attenuation and that a relatively small number of large grains can dominate the scattering processes.