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Sample records for brachypodium distachyon grain

  1. Grain dormancy and light quality effects on germination in the model grass Brachypodium distachyon.

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    Barrero, José M; Jacobsen, John V; Talbot, Mark J; White, Rosemary G; Swain, Stephen M; Garvin, David F; Gubler, Frank

    2012-01-01

    • Lack of grain dormancy in cereal crops such as barley and wheat is a common problem affecting farming areas around the world, causing losses in yield and quality because of preharvest sprouting. Control of seed or grain dormancy has been investigated extensively using various approaches in different species, including Arabidopsis and cereals. However, the use of a monocot model plant such as Brachypodium distachyon presents opportunities for the discovery of new genes related to grain dormancy that are not present in modern commercial crops. • In this work we present an anatomical description of the Brachypodium caryopsis, and we describe the dormancy behaviour of six common diploid Brachypodium inbred genotypes. We also study the effect of light quality (blue, red and far-red) on germination, and analyse changes in abscisic acid levels and gene expression between a dormant and a non-dormant Brachypodium genotype. • Our results indicate that different genotypes display high natural variability in grain dormancy and that the characteristics of dormancy and germination are similar to those found in other cereals. • We propose that Brachypodium is an ideal model for studies of grain dormancy in grasses and can be used to identify new strategies for increasing grain dormancy in crop species.

  2. Anther ontogeny in Brachypodium distachyon.

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    Sharma, Akanksha; Singh, Mohan B; Bhalla, Prem L

    2015-03-01

    Brachypodium distachyon has emerged as a model plant for the improvement of grain crops such as wheat, barley and oats and for understanding basic biological processes to facilitate the development of grasses as superior energy crops. Brachypodium is also the first species of the grass subfamily Pooideae with a sequenced genome. For obtaining a better understanding of the mechanisms controlling male gametophyte development in B. distachyon, here we report the cellular changes during the stages of anther development, with special reference to the development of the anther wall. Brachypodium anthers are tetrasporangiate and follow the typical monocotyledonous-type anther wall formation pattern. Anther differentiation starts with the appearance of archesporial cells, which divide to generate primary parietal and primary sporogenous cells. The primary parietal cells form two secondary parietal layers. Later, the outer secondary parietal layer directly develops into the endothecium and the inner secondary parietal layer forms an outer middle layer and inner tapetum by periclinal division. The anther wall comprises an epidermis, endothecium, middle layer and the secretory-type tapetum. Major documented events of anther development include the degradation of a secretory-type tapetum and middle layer during the course of development and the rapid formation of U-shaped endothecial thickenings in the mature pollen grain stage. The tapetum undergoes degeneration at the tetrad stage and disintegrates completely at the bicellular stage of pollen development. The distribution of insoluble polysaccharides in the anther layers and connective tissue through progressive developmental stages suggests their role in the development of male gametophytes. Until sporogenous cell stage, the amount of insoluble polysaccharides in the anther wall was negligible. However, abundant levels of insoluble polysaccharides were observed during microspore mother cell and tetrad stages and gradually

  3. Starch bioengineering in Brachypodium distachyon

    DEFF Research Database (Denmark)

    Tanackovic, Vanja; Svensson, Jan Tommy; Glaring, Mikkel Andreas;

    2011-01-01

    Brachypodium distachyon was recently introduced as a model plant for temperate cereals (Opanowicz et al., 2008). We aim to establish Brachypodium as a model for cereal starch metabolism. Grain starch from two lines: Bd21 and Bd21-3 are being characterized. Microscopic, chemical and structural data...... including amylopectin chain length distribution, phosphate content and amylose content provided further evidence for the close relationship to temperate cereals even though starch content and starch granule size were considerably lower than that for barley (Hordeum vulgare). Bioinformatics analyses...... identified starch biosynthesis genes including seven soluble starch synthases (SS), three granule bound starch syntheses (GBSS), four starch branching enzymes (SBE), two glucan- and one phosphoglucan- water dikinases (GWD, PWD). Phylogenetic analysis based on the SS genes provided evidence for a close...

  4. The deposition and characterization of starch in Brachypodium distachyon

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    Tanackovic, Vanja; Svensson, Jan T.; Jensen, Susanne Langgård;

    2014-01-01

    Brachypodium distachyon is a non-domesticated cereal. Nonetheless, Brachypodium was recently introduced as a model plant for temperate cereals. This study compares grain starch metabolism in Brachypodium and barley (Hordeum vulgare). In Brachypodium, we identified and annotated 28 genes involved...... in starch metabolism and identified important motifs including transit peptides and putative carbohydrate-binding modules (CBMs) of the families CBM20, CBM45, CBM48, and CBM53. Starch content was markedly lower in Brachypodium grains (12%) compared to barley grains (47%). Brachypodium starch granules were...... doughnut shaped and bimodally distributed into distinct small B-type (2.5-10 µm) and very small C-type (0.5-2.5 µm) granules. Large A-type granules, typical of cereals, were absent. Starch-bound phosphate, important for starch degradation, was 2-fold lower in Brachypodium compared with barley indicating...

  5. Agrobacterium-mediated transformation of Brachypodium distachyon.

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    Thole, Vera; Vain, Philippe

    2012-01-01

    Brachypodium distachyon is an attractive genomics and biological model system for grass research. Recently, the complete annotated genome sequence of the diploid line Bd21 has been released. Genetic transformation technologies are critical for the discovery and validation of gene function in Brachypodium. Here, we describe an efficient procedure enabling the Agrobacterium-mediated transformation of a range of diploid and polyploid genotypes of Brachypodium. The procedure relies on the transformation of compact embryogenic calli derived from immature embryos using either chemical selection alone or a combination of chemical and visual screening of transformed tissues and plants. Transformation efficiencies of around 20% can routinely be achieved using this protocol. In the context of the BrachyTAG programme (BrachyTAG.org), this procedure made possible the mass production of Bd21T-DNA mutant plant lines.

  6. Use of Agrobacterium rhizogenes Strain 18r12v and Paromomycin Selection for Transformation of Brachypodium distachyon and Brachypodium sylvaticum.

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    Collier, Ray; Bragg, Jennifer; Hernandez, Bryan T; Vogel, John P; Thilmony, Roger

    2016-01-01

    The genetic transformation of monocot grasses is a resource intensive process, the quality and efficiency of which is dependent in part upon the method of DNA introduction, as well as the ability to effectively separate transformed from wildtype tissue. Agrobacterium-mediated transformation of Brachypodium has relied mainly on Agrobacterium tumefaciens strain AGL1. Currently the antibiotic hygromycin B has been the selective agent of choice for robust identification of transgenic calli in Brachypodium distachyon and Brachypodium sylvaticum but few other chemicals have been shown to work as well for selection of transgenic Brachypodium cells in tissue culture. This study demonstrates that Agrobacterium rhizogenes strain 18r12v and paromomycin selection can be successfully used for the efficient generation of transgenic B. distachyon and B. sylvaticum. Additionally we observed that the transformation rates were similar to or higher than those obtained with A. tumefaciens strain AGL1 and hygromycin selection. The A. rhizogenes strain 18r12v harboring the pARS1 binary vector and paromomycin selection is an effective means of generating transgenic Brachypodium plants. This novel approach will facilitate the transgenic complementation of T-DNA knockout mutants of B. distachyon which were created using hygromycin selection, as well as aid the implementation of more complex genome manipulation strategies which require multiple rounds of transformation.

  7. Use of Agrobacterium rhizogenes strain 18r12v and paromomycin selection for transformation of Brachypodium distachyon and Brachypodium sylvaticum

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    Ray eCollier

    2016-05-01

    Full Text Available The genetic transformation of monocot grasses is a resource intensive process, the quality and efficiency of which is dependent in part upon the method of DNA introduction, as well as the ability to effectively separate transformed from wildtype tissue. Agrobacterium-mediated transformation of Brachypodium has relied mainly on Agrobacterium tumefaciens strain AGL1. Currently the antibiotic hygromycin B has been the selective agent of choice for robust identification of transgenic calli in Brachypodium distachyon and Brachypodium sylvaticum but few other chemicals have been shown to work as well for selection of transgenic Brachypodium cells in tissue culture. This study demonstrates that Agrobacterium rhizogenes strain 18r12v and paromomycin selection can be successfully used for the efficient generation of transgenic B. distachyon and B. sylvaticum. Additionally we observed that the transformation rates were similar to or higher than those obtained with A. tumefaciens strain AGL1 and hygromycin selection. The A. rhizogenes strain 18r12v harboring the pARS1 binary vector and paromomycin selection is an effective means of generating transgenic Brachypodium plants. This novel approach will facilitate the transgenic complementation of T-DNA knockout mutants of B. distachyon which were created using hygromycin selection, as well as aid the implementation of more complex genome manipulation strategies which require multiple rounds of transformation.

  8. Brachypodium distachyon as a model system for studies of copper transport in cereal crops

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    Ha-il eJung

    2014-05-01

    Full Text Available Copper (Cu is an essential micronutrient that performs a remarkable array of functions in plants including photosynthesis, cell wall remodeling, flowering, and seed set. Of the world's major cereal crops, wheat, barley, and oat are the most sensitive to Cu deficiency. Cu deficient soils include alkaline soils, which occupy approximately 30% of the world’s arable lands, and organic soils that occupy an estimated 19% of arable land in Europe. We used Brachypodium distachyon (brachypodium as a proxy for wheat and other grain cereals to initiate analyses of the molecular mechanisms underlying their increased susceptibility to Cu deficiency. In this report, we focus on members of the CTR/COPT family of Cu transporters because their homologs in A. thaliana are transcriptionally upregulated in Cu-limited conditions and are involved either in Cu uptake from soils into epidermal cells in the root, or long-distance transport and distribution of Cu in photosynthetic tissues. We found that of five COPT proteins in brachypodium, BdCOPT3 and BdCOPT4 localize to the plasma membrane and are transcriptionally upregulated in roots and leaves by Cu deficiency. We also found that BdCOPT3, BdCOPT4, and BdCOPT5 confer low affinity Cu transport, in contrast to their counterparts in A. thaliana that confer high affinity Cu transport. These data suggest that increased sensitivity to Cu deficiency in some grass species may arise from lower efficiency and, possibly, other properties of components of Cu uptake and tissue partitioning systems and reinforce the importance of using brachypodium as a model for the comprehensive analyses of Cu homeostasis in cereal crops.

  9. Diversity of morphology and function in arbuscular mycorrhizal symbioses in Brachypodium distachyon.

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    Hong, Jeon J; Park, Yong-Soon; Bravo, Armando; Bhattarai, Kishor K; Daniels, Dierdra A; Harrison, Maria J

    2012-09-01

    Brachypodium distachyon is a grass species that serves as a useful model for wheat and also for many of the grass species proposed as feedstocks for bioenergy production. Here, we monitored B. distachyon symbioses with five different arbuscular mycorrhizal (AM) fungi and identified symbioses that vary functionally with respect to plant performance. Three symbioses promoted significant increases in shoot phosphorus (P) content and shoot growth of Brachypodium, while two associations were neutral. The Brachypodium/Glomus candidum symbiosis showed a classic 'Paris-type' morphology. In the other four AM symbioses, hyphal growth was exclusively intracellular and linear; hyphal coils were not observed and arbuscules were abundant. Expression of the Brachypodium ortholog of the symbiosis-specific phosphate (Pi) transporter MtPT4 did not differ significantly in these five interactions indicating that the lack of apparent functionality did not result from a failure to express this gene or several other AM symbiosis-associated genes. Analysis of the expression patterns of the complete PHT1 Pi transporter gene family and AMT2 gene family in B. distachyon/G. intraradices mycorrhizal roots identified additional family members induced during symbiosis and again, transcript levels were similar in the different Brachypodium AM symbioses. This initial morphological, molecular and functional characterization provides a framework for future studies of functional diversity in AM symbiosis in B. distachyon.

  10. Genome sequence analysis of the model grass Brachypodium distachyon: insights into grass genome evolution

    Energy Technology Data Exchange (ETDEWEB)

    Schulman, Al

    2009-08-09

    Three subfamilies of grasses, the Erhardtoideae (rice), the Panicoideae (maize, sorghum, sugar cane and millet), and the Pooideae (wheat, barley and cool season forage grasses) provide the basis of human nutrition and are poised to become major sources of renewable energy. Here we describe the complete genome sequence of the wild grass Brachypodium distachyon (Brachypodium), the first member of the Pooideae subfamily to be completely sequenced. Comparison of the Brachypodium, rice and sorghum genomes reveals a precise sequence- based history of genome evolution across a broad diversity of the grass family and identifies nested insertions of whole chromosomes into centromeric regions as a predominant mechanism driving chromosome evolution in the grasses. The relatively compact genome of Brachypodium is maintained by a balance of retroelement replication and loss. The complete genome sequence of Brachypodium, coupled to its exceptional promise as a model system for grass research, will support the development of new energy and food crops

  11. Whole plant phenotypic variability in nitrogen and phosphorus response of Brachypodium distachyon

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    This work evaluates the phenotypic response of the model grass (Brachypodium distachyon) to nitrogen and phosphorus nutrition. Reference line Bd21-3 was grown in sand under controlled conditions using 11 phosphorus and 11 nitrogen application rates. We established a dose-response curve for both nit...

  12. Comparative analyses reveal potential uses of Brachypodium distachyon as a model for cold stress responses in temperate grasses

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    Li Chuan

    2012-05-01

    Full Text Available Abstract Background Little is known about the potential of Brachypodium distachyon as a model for low temperature stress responses in Pooideae. The ice recrystallization inhibition protein (IRIP genes, fructosyltransferase (FST genes, and many C-repeat binding factor (CBF genes are Pooideae specific and important in low temperature responses. Here we used comparative analyses to study conservation and evolution of these gene families in B. distachyon to better understand its potential as a model species for agriculturally important temperate grasses. Results Brachypodium distachyon contains cold responsive IRIP genes which have evolved through Brachypodium specific gene family expansions. A large cold responsive CBF3 subfamily was identified in B. distachyon, while CBF4 homologs are absent from the genome. No B. distachyon FST gene homologs encode typical core Pooideae FST-motifs and low temperature induced fructan accumulation was dramatically different in B. distachyon compared to core Pooideae species. Conclusions We conclude that B. distachyon can serve as an interesting model for specific molecular mechanisms involved in low temperature responses in core Pooideae species. However, the evolutionary history of key genes involved in low temperature responses has been different in Brachypodium and core Pooideae species. These differences limit the use of B. distachyon as a model for holistic studies relevant for agricultural core Pooideae species.

  13. Reduced susceptibility to Fusarium head blight in Brachypodium distachyon through priming with the Fusarium mycotoxin deoxynivalenol.

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    Blümke, Antje; Sode, Björn; Ellinger, Dorothea; Voigt, Christian A

    2015-06-01

    The fungal cereal pathogen Fusarium graminearum produces deoxynivalenol (DON) during infection. The mycotoxin DON is associated with Fusarium head blight (FHB), a disease that can cause vast grain losses. Whilst investigating the suitability of Brachypodium distachyon as a model for spreading resistance to F. graminearum, we unexpectedly discovered that DON pretreatment of spikelets could reduce susceptibility to FHB in this model grass. We started to analyse the cell wall changes in spikelets after infection with F. graminearum wild-type and defined mutants: the DON-deficient Δtri5 mutant and the DON-producing lipase disruption mutant Δfgl1, both infecting only directly inoculated florets, and the mitogen-activated protein (MAP) kinase disruption mutant Δgpmk1, with strongly decreased virulence but intact DON production. At 14 days post-inoculation, the glucose amounts in the non-cellulosic cell wall fraction were only increased in spikelets infected with the DON-producing strains wild-type, Δfgl1 and Δgpmk1. Hence, we tested for DON-induced cell wall changes in B. distachyon, which were most prominent at DON concentrations ranging from 1 to 100 ppb. To test the involvement of DON in defence priming, we pretreated spikelets with DON at a concentration of 1 ppm prior to F. graminearum wild-type infection, which significantly reduced FHB disease symptoms. The analysis of cell wall composition and plant defence-related gene expression after DON pretreatment and fungal infection suggested that DON-induced priming of the spikelet tissue contributed to the reduced susceptibility to FHB.

  14. Comparative and Evolutionary Analysis of Grass Pollen Allergens Using Brachypodium distachyon as a Model System

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    Sharma, Akanksha; Sharma, Niharika; Bhalla, Prem; Singh, Mohan

    2017-01-01

    Comparative genomics have facilitated the mining of biological information from a genome sequence, through the detection of similarities and differences with genomes of closely or more distantly related species. By using such comparative approaches, knowledge can be transferred from the model to non-model organisms and insights can be gained in the structural and evolutionary patterns of specific genes. In the absence of sequenced genomes for allergenic grasses, this study was aimed at understanding the structure, organisation and expression profiles of grass pollen allergens using the genomic data from Brachypodium distachyon as it is phylogenetically related to the allergenic grasses. Combining genomic data with the anther RNA-Seq dataset revealed 24 pollen allergen genes belonging to eight allergen groups mapping on the five chromosomes in B. distachyon. High levels of anther-specific expression profiles were observed for the 24 identified putative allergen-encoding genes in Brachypodium. The genomic evidence suggests that gene encoding the group 5 allergen, the most potent trigger of hay fever and allergic asthma originated as a pollen specific orphan gene in a common grass ancestor of Brachypodium and Triticiae clades. Gene structure analysis showed that the putative allergen-encoding genes in Brachypodium either lack or contain reduced number of introns. Promoter analysis of the identified Brachypodium genes revealed the presence of specific cis-regulatory sequences likely responsible for high anther/pollen-specific expression. With the identification of putative allergen-encoding genes in Brachypodium, this study has also described some important plant gene families (e.g. expansin superfamily, EF-Hand family, profilins etc) for the first time in the model plant Brachypodium. Altogether, the present study provides new insights into structural characterization and evolution of pollen allergens and will further serve as a base for their functional

  15. Memory of the Vernalized State in Plants including the Model Grass Brachypodium distachyon

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    Daniel P Woods

    2014-03-01

    Full Text Available Plant species that have a vernalization requirement exhibit variation in the ability to remember winter—i.e., variation in the stability of the vernalized state. Studies in Arabidopsis have demonstrated that molecular memory involves changes in the chromatin state and expression of the flowering repressor FLOWERING LOCUS C, and have revealed that single-gene differences can have large effects on the stability of the vernalized state. In the perennial Arabidopsis relative Arabis alpina, the lack of memory of winter is critical for its perennial life history. Our studies of flowering behavior in the model grass Brachypodium distachyon reveal extensive variation in the vernalization requirement, and studies of a particular Brachypodium accession that has a qualitative requirement for both cold exposure and inductive daylength reveals that Brachypodium can exhibit a highly stable vernalized state.

  16. PHYTOCHROME C is an essential light receptor for photoperiodic flowering in the temperate grass, Brachypodium distachyon.

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    Woods, Daniel P; Ream, Thomas S; Minevich, Gregory; Hobert, Oliver; Amasino, Richard M

    2014-09-01

    We show that in the temperate grass, Brachypodium distachyon, PHYTOCHROME C (PHYC), is necessary for photoperiodic flowering. In loss-of-function phyC mutants, flowering is extremely delayed in inductive photoperiods. PHYC was identified as the causative locus by utilizing a mapping by sequencing pipeline (Cloudmap) optimized for identification of induced mutations in Brachypodium. In phyC mutants the expression of Brachypodium homologs of key flowering time genes in the photoperiod pathway such as GIGANTEA (GI), PHOTOPERIOD 1 (PPD1/PRR37), CONSTANS (CO), and florigen/FT are greatly attenuated. PHYC also controls the day-length dependence of leaf size as the effect of day length on leaf size is abolished in phyC mutants. The control of genes upstream of florigen production by PHYC was likely to have been a key feature of the evolution of a long-day flowering response in temperate pooid grasses.

  17. Cell walls and the developmental anatomy of the Brachypodium distachyon stem internode.

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    Dominick A Matos

    Full Text Available While many aspects of plant cell wall polymer structure are known, their spatial and temporal distribution within the stem are not well understood. Here, we studied vascular system and fiber development, which has implication for both biofuel feedstock conversion efficiency and crop yield. The subject of this study, Brachypodium distachyon, has emerged as a grass model for food and energy crop research. Here, we conducted our investigation using B. distachyon by applying various histological approaches and Fourier transform infrared spectroscopy to the stem internode from three key developmental stages. While vascular bundle size and number did not change over time, the size of the interfascicular region increased dramatically, as did cell wall thickness. We also describe internal stem internode anatomy and demonstrate that lignin deposition continues after crystalline cellulose and xylan accumulation ceases. The vascular bundle anatomy of B. distachyon appears to be highly similar to domesticated grasses. While the arrangement of bundles within the stem is highly variable across grasses, B. distachyon appears to be a suitable model for the rind of large C4 grass crops. A better understanding of growth and various anatomical and cell wall features of B. distachyon will further our understanding of plant biomass accumulation processes.

  18. Genome Wide Analysis of Nucleotide-Binding Site Disease Resistance Genes in Brachypodium distachyon

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    Shenglong Tan

    2012-01-01

    Full Text Available Nucleotide-binding site (NBS disease resistance genes play an important role in defending plants from a variety of pathogens and insect pests. Many R-genes have been identified in various plant species. However, little is known about the NBS-encoding genes in Brachypodium distachyon. In this study, using computational analysis of the B. distachyon genome, we identified 126 regular NBS-encoding genes and characterized them on the bases of structural diversity, conserved protein motifs, chromosomal locations, gene duplications, promoter region, and phylogenetic relationships. EST hits and full-length cDNA sequences (from Brachypodium database of 126 R-like candidates supported their existence. Based on the occurrence of conserved protein motifs such as coiled-coil (CC, NBS, leucine-rich repeat (LRR, these regular NBS-LRR genes were classified into four subgroups: CC-NBS-LRR, NBS-LRR, CC-NBS, and X-NBS. Further expression analysis of the regular NBS-encoding genes in Brachypodium database revealed that these genes are expressed in a wide range of libraries, including those constructed from various developmental stages, tissue types, and drought challenged or nonchallenged tissue.

  19. Brachypodium distachyon as a model for defining the allergen potential of non-prolamin proteins.

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    Juhász, A; Gell, Gy; Sebestyén, E; Haraszi, R; Tamás, L; Balázs, E

    2012-08-01

    Epitope databases and the protein sequences of published plant genomes are suitable to identify some of the proteins causing food allergies and sensitivities. Brachypodium distachyon, a diploid wild grass with a sequenced genome and low prolamin content, is the closest relative of the allergen cereals, such as wheat or barley. Using the Brachypodium genome sequence, a workflow has been developed to identify potentially harmful proteins which may cause either celiac disease or wheat allergy-related symptoms. Seed tissue-specific expression of the potential allergens has been determined, and intact epitopes following an in silico digestion with several endopeptidases have been identified. Molecular function of allergen proteins has been evaluated using Gene Ontology terms. Biologically overrepresented proteins and potentially allergen protein families have been identified.

  20. Exploring valid reference genes for gene expression studies in Brachypodium distachyon by real-time PCR

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    Xiang Fengning

    2008-11-01

    Full Text Available Abstract Background The wild grass species Brachypodium distachyon (Brachypodium hereafter is emerging as a new model system for grass crop genomics research and biofuel grass biology. A draft nuclear genome sequence is expected to be publicly available in the near future; an explosion of gene expression studies will undoubtedly follow. Therefore, stable reference genes are necessary to normalize the gene expression data. Results A systematic exploration of suitable reference genes in Brachypodium is presented here. Nine reference gene candidates were chosen, and their gene sequences were obtained from the Brachypodium expressed sequence tag (EST databases. Their expression levels were examined by quantitative real-time PCR (qRT-PCR using 21 different Brachypodium plant samples, including those from different plant tissues and grown under various growth conditions. Effects of plant growth hormones were also visualized in the assays. The expression stability of the candidate genes was evaluated using two analysis software packages, geNorm and NormFinder. In conclusion, the ubiquitin-conjugating enzyme 18 gene (UBC18 was validated as a suitable reference gene across all the plant samples examined. While the expression of the polyubiquitin genes (Ubi4 and Ubi10 was most stable in different plant tissues and growth hormone-treated plant samples, the expression of the S-adenosylmethionine decarboxylase gene (SamDC ranked was most stable in plants grown under various environmental stresses. Conclusion This study identified the reference genes that are most suitable for normalizing the gene expression data in Brachypodium. These reference genes will be particularly useful when stress-responsive genes are analyzed in order to produce transgenic plants that exhibit enhanced stress resistance.

  1. The α-gliadin genes from Brachypodium distachyon L. provide evidence for a significant gap in the current genome assembly.

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    Chen, G X; Lv, D W; Li, W D; Subburaj, S; Yu, Z T; Wang, Y J; Li, X H; Wang, K; Ye, X G; Ma, Wujun; Yan, Y M

    2014-03-01

    Brachypodium distachyon, is a new model plant for most cereal crops while gliadin is a class of wheat storage proteins related with wheat quality attributes. In the published B. distachyon genome sequence databases, no gliadin gene is found. In the current study, a number of gliadin genes in B. distachyon were isolated, which is contradictory to the results of genome sequencing projects. In our study, the B. distachyon seeds were found to have no gliadin protein expression by gel electrophoresis, reversed-phase high-performance liquid chromatography and Western blotting analysis. However, Southern blotting revealed a presence of more than ten copies of α-gliadin coding genes in B. distachyon. By means of AS-PCR amplification, four novel full-ORF α-gliadin genes, and 26 pseudogenes with at least one stop codon as well as their promoter regions were cloned and sequenced from different Brachypodium accessions. Sequence analysis revealed a few of single-nucleotide polymorphisms among these genes. Most pseudogenes were resulted from a C to T change, leading to the generation of TAG or TAA in-frame stop codon. To compare both the full-ORFs and the pseudogenes among Triticum and Triticum-related species, their structural characteristics were analyzed. Based on the four T cell stimulatory toxic epitopes and two ployglutamine domains, Aegilops, Triticum, and Brachypodium species were found to be more closely related. The phylogenetic analysis further revealed that B. distachyon was more closely related to Aegilops tauschii, Aegilops umbellulata, and the A or D genome of Triticum aestivum. The α-gliadin genes were able to express successfully in E. coli using the functional T7 promoter. The relative and absolute quantification of the transcripts of α-gliadin genes in wheat was much higher than that in B. distachyon. The abundant pseudogenes may affect the transcriptional and/or posttranscriptional level of the α-gliadin in B. distachyon.

  2. Investigations of barley stripe mosaic virus as a gene silencing vector in barley roots and in Brachypodium distachyon and oat

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    Pacak, Andrzej; Geisler, Katrin; Jørgensen, Bodil;

    2010-01-01

    -expressed genes we wanted to explore the potential of BSMV for silencing genes in root tissues. Furthermore, the newly completed genome sequence of the emerging cereal model species Brachypodium distachyon as well as the increasing amount of EST sequence information available for oat (Avena species) have created...

  3. Analysis of saccharification in Brachypodium distachyon stems under mild conditions of hydrolysis

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    Statham Emily R

    2008-10-01

    Full Text Available Abstract Background Brachypodium distachyon constitutes an excellent model species for grasses. It is a small, easily propagated, temperate grass with a rapid life cycle and a small genome. It is a self-fertile plant that can be transformed with high efficiency using Agrobacteria and callus derived from immature embryos. In addition, considerable genetic and genomic resources are becoming available for this species in the form of mapping populations, large expressed sequence tag collections, T-DNA insertion lines and, in the near future, the complete genome sequence. The development of Brachypodium as a model species is of particular value in the areas of cell wall and biomass research, where differences between dicots and grasses are greatest. Here we explore the effect of mild conditions of pretreatment and hydrolysis in Brachypodium stem segments as a contribution for the establishment of sensitive screening of the saccharification properties in different genetic materials. Results The non-cellulosic monosaccharide composition of Brachypodium is closely related to grasses of agricultural importance and significantly different from the dicot model Arabidopsis thaliana. Diluted acid pretreatment of stem segments produced significant release of sugars and negatively affected the amount of sugars obtained by enzymatic hydrolysis. Monosaccharide and oligosaccharide analysis showed that the hemicellulose fraction is the main target of the enzymatic activity under the modest hydrolytic conditions used in our assays. Scanning electron microscopy analysis of the treated materials showed progressive exposure of fibrils in the stem segments. Conclusion Results presented here indicate that under mild conditions cellulose and hemicellulose are hydrolysed to differing extents, with hemicellulose hydrolysis predominating. We anticipate that the sub-optimal conditions for hydrolysis identified here will provide a sensitive assay to detect variations in

  4. Molecular Characterization and Expression Profiling of NAC Transcription Factors in Brachypodium distachyon L.

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    Zhu, Gengrui; Chen, Guanxing; Zhu, Jiantang; Zhu, Yan; Lu, Xiaobing; Li, Xiaohui; Hu, Yingkao; Yan, Yueming

    2015-01-01

    NAC (NAM, ATAF1/2, CUC2) transcription factors are involved in regulating plant developmental processes and response to environmental stresses. Brachypodium distachyon is an emerging model system for cereals, temperate grasses and biofuel crops. In this study, a comprehensive investigation of the molecular characterizations, phylogenetics and expression profiles under various abiotic stresses of the NAC gene family in Brachypodium distachyon was performed. In total, 118 BNAC genes in B. distachyon were identified, of which 22 (18.64%) were tandemly duplicated and segmentally duplicated, respectively. The Bayesian phylogenetic inference using Markov Chain Monte Carlo (MCMC) algorithms showed that they were divided into two clades and fourteen subfamilies, supported by similar motif compositions within one subfamily. Some critical amino acids detected using DIVERGE v3.0 might contribute to functional divergence among subfamilies. The different exon-intron organizations among subfamilies revealed structural differentiation. Promoter sequence predictions showed that the BNAC genes were involved in various developmental processes and diverse stress responses. Three NAC domain-encoding genes (BNAC012, BNAC078 and BNAC108), orthologous of NAC1, were targeted by five miRNA164 (Bdi-miR164a-c, e, f), suggesting that they might function in lateral organ enlargement, floral development and the responses to abiotic stress. Eleven (~9.32%) BNAC proteins containing α-helical transmembrane motifs were identified. 23 representative BNAC genes were analyzed by quantitative real-time PCR, showing different expression patterns under various abiotic stresses, of which 18, 17 and 11 genes were up-regulated significantly under drought, H2O2 and salt stresses, respectively. Only four and two genes were up-regulated under cold and cadmium stresses, respectively. Dynamic transcriptional expression analysis revealed that six genes showed constitutive expression and period

  5. Molecular Characterization and Expression Profiling of NAC Transcription Factors in Brachypodium distachyon L.

    Directory of Open Access Journals (Sweden)

    Gengrui Zhu

    Full Text Available NAC (NAM, ATAF1/2, CUC2 transcription factors are involved in regulating plant developmental processes and response to environmental stresses. Brachypodium distachyon is an emerging model system for cereals, temperate grasses and biofuel crops. In this study, a comprehensive investigation of the molecular characterizations, phylogenetics and expression profiles under various abiotic stresses of the NAC gene family in Brachypodium distachyon was performed. In total, 118 BNAC genes in B. distachyon were identified, of which 22 (18.64% were tandemly duplicated and segmentally duplicated, respectively. The Bayesian phylogenetic inference using Markov Chain Monte Carlo (MCMC algorithms showed that they were divided into two clades and fourteen subfamilies, supported by similar motif compositions within one subfamily. Some critical amino acids detected using DIVERGE v3.0 might contribute to functional divergence among subfamilies. The different exon-intron organizations among subfamilies revealed structural differentiation. Promoter sequence predictions showed that the BNAC genes were involved in various developmental processes and diverse stress responses. Three NAC domain-encoding genes (BNAC012, BNAC078 and BNAC108, orthologous of NAC1, were targeted by five miRNA164 (Bdi-miR164a-c, e, f, suggesting that they might function in lateral organ enlargement, floral development and the responses to abiotic stress. Eleven (~9.32% BNAC proteins containing α-helical transmembrane motifs were identified. 23 representative BNAC genes were analyzed by quantitative real-time PCR, showing different expression patterns under various abiotic stresses, of which 18, 17 and 11 genes were up-regulated significantly under drought, H2O2 and salt stresses, respectively. Only four and two genes were up-regulated under cold and cadmium stresses, respectively. Dynamic transcriptional expression analysis revealed that six genes showed constitutive expression and period

  6. Centromeres cluster de novo at the beginning of meiosis in Brachypodium distachyon.

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    Ruoyu Wen

    Full Text Available In most eukaryotes that have been studied, the telomeres cluster into a bouquet early in meiosis, and in wheat and its relatives and in Arabidopsis the centromeres pair at the same time. In Arabidopsis, the telomeres do not cluster as a typical telomere bouquet on the nuclear membrane but are associated with the nucleolus both somatically and at the onset of meiosis. We therefore assessed whether Brachypodium distachyon, a monocot species related to cereals and whose genome is approximately twice the size of Arabidopsis thaliana, also exhibited an atypical telomere bouquet and centromere pairing. In order to investigate the occurrence of a bouquet and centromere pairing in B distachyon, we first had to establish protocols for studying meiosis in this species. This enabled us to visualize chromosome behaviour in meiocytes derived from young B distachyon spikelets in three-dimensions by fluorescent in situ hybridization (FISH, and accurately to stage meiosis based on chromatin morphology in relation to spikelet size and the timing of sample collection. Surprisingly, this study revealed that the centromeres clustered as a single site at the same time as the telomeres also formed a bouquet or single cluster.

  7. The complete chloroplast genome sequence of Brachypodium distachyon: sequence comparison and phylogenetic analysis of eight grass plastomes

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    Anderson Olin D

    2008-07-01

    Full Text Available Abstract Background Wheat, barley, and rye, of tribe Triticeae in the Poaceae, are among the most important crops worldwide but they present many challenges to genomics-aided crop improvement. Brachypodium distachyon, a close relative of those cereals has recently emerged as a model for grass functional genomics. Sequencing of the nuclear and organelle genomes of Brachypodium is one of the first steps towards making this species available as a tool for researchers interested in cereals biology. Findings The chloroplast genome of Brachypodium distachyon was sequenced by a combinational approach using BAC end and shotgun sequences derived from a selected BAC containing the entire chloroplast genome. Comparative analysis indicated that the chloroplast genome is conserved in gene number and organization with respect to those of other cereals. However, several Brachypodium genes evolve at a faster rate than those in other grasses. Sequence analysis reveals that rice and wheat have a ~2.1 kb deletion in their plastid genomes and this deletion must have occurred independently in both species. Conclusion We demonstrate that BAC libraries can be used to sequence plastid, and likely other organellar, genomes. As expected, the Brachypodium chloroplast genome is very similar to those of other sequenced grasses. The phylogenetic analyses and the pattern of insertions and deletions in the chloroplast genome confirmed that Brachypodium is a close relative of the tribe Triticeae. Nevertheless, we show that some large indels can arise multiple times and may confound phylogenetic reconstruction.

  8. Linking dynamic phenotyping with metabolite analysis to study natural variation in drought responses of Brachypodium distachyon

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    Lorraine H.C. Fisher

    2016-11-01

    Full Text Available Drought is an important environmental stress limiting the productivity of major crops worldwide. Understanding drought tolerance and possible mechanisms for improving drought resistance is therefore a prerequisite to develop drought-tolerant crops that produce significant yields with reduced amounts of water. Brachypodium distachyon (Brachypodium is a key model species for cereals, forage grasses and energy grasses. In this study, initial screening of a Brachypodium germplasm collection consisting of 138 different ecotypes exposed to progressive drought, highlighted the natural variation in morphology, biomass accumulation and responses to drought stress. A core set of ten ecotypes, classified as being either tolerant, susceptible or intermediate, in response to drought stress, were exposed to mild or severe (respectively 15% and 0% soil water content drought stress and phenomic parameters linked to growth and colour changes were assessed. When exposed to severe drought stress, phenotypic data and metabolite profiling combined with multivariate analysis revealed a remarkable consistency in separating the selected ecotypes into their different pre-defined drought tolerance groups. Increases in several metabolites, including for the phytohormones jasmonic acid and salicylic acid, and TCA-cycle intermediates, were positively correlated with biomass yield and with reduced yellow pixel counts; suggestive of delayed senescence, both key target traits for crop improvement to drought stress. While metabolite analysis also separated ecotypes into the distinct tolerance groupings after exposure to mild drought stress, similar analysis of the phenotypic data failed to do so, confirming the value of metabolomics to investigate early responses to drought stress. The results highlight the potential of combining the analyses of phenotypic and metabolic responses to identify key mechanisms and markers associated with drought tolerance in both the Brachypodium

  9. Investigations of barley stripe mosaic virus as a gene silencing vector in barley roots and in Brachypodium distachyon and oat

    DEFF Research Database (Denmark)

    Pacak, Andrzej; Geisler, Katrin; Jørgensen, Bodil;

    2010-01-01

    -expressed genes we wanted to explore the potential of BSMV for silencing genes in root tissues. Furthermore, the newly completed genome sequence of the emerging cereal model species Brachypodium distachyon as well as the increasing amount of EST sequence information available for oat (Avena species) have created...... the wealth of genome information in the new cereal model plant B. distachyon. On the other hand, the silencing induced by BSMV in oat seemed too weak to be of practical use. The new BSMV vectors modified for ligation-free cloning will allow rapid insertion of plant gene fragments for future experiments....

  10. Molecular and Physiological Analysis of Growth-Limiting Drought Stress in Brachypodium distachyon Leaves

    Institute of Scientific and Technical Information of China (English)

    Wim Verelst; Edoardo Bertolini; Stefanie De Bodt; Klaas Vandepoele; Marlies Demeulenaere; Mario Enrico Pè; Dirk Inzé

    2013-01-01

    The drought-tolerant grass Brachypodium distachyon is an emerging model species for temperate grasses and cereal crops.To explore the usefulness of this species for drought studies,a reproducible in vivo drought assay was developed.Spontaneous soil drying led to a 45% reduction in leaf size,and this was mostly due to a decrease in cell expansion,whereas cell division remained largely unaffected by drought.To investigate the molecular basis of the observed leaf growth reduction,the third Brachypodium leaf was dissected in three zones,namely proliferation,expansion,and mature zones,and subjected to transcriptome analysis,based on a whole-genome tiling array.This approach allowed us to highlight that transcriptome profiles of different developmental leaf zones respond differently to drought.Several genes and functional processes involved in drought tolerance were identified.The transcriptome data suggest an increased energy availability in the proliferation zones,along with an up-regulation of sterol synthesis that may influence membrane fluidity.This information may be used to improve the tolerance of temperate cereals to drought,which is undoubtedly one of the major environmental challenges faced by agriculture today and in the near future.

  11. Brachypodium distachyon-Cochliobolus sativus Pathosystem is a New Model for Studying Plant-Fungal Interactions in Cereal Crops.

    Science.gov (United States)

    Zhong, Shaobin; Ali, Shaukat; Leng, Yueqiang; Wang, Rui; Garvin, David F

    2015-04-01

    Cochliobolus sativus (anamorph: Bipolaris sorokiniana) causes spot blotch, common root rot, and kernel blight or black point in barley and wheat. However, little is known about the molecular mechanisms underlying the pathogenicity of C. sativus or the molecular basis of resistance and susceptibility in the hosts. This study aims to establish the model grass Brachypodium distachyon as a new model for studying plant-fungus interactions in cereal crops. Six B. distachyon lines were inoculated with five C. sativus isolates. The results indicated that all six B. distachyon lines were infected by the C. sativus isolates, with their levels of resistance varying depending on the fungal isolates used. Responses ranging from hypersensitive response-mediated resistance to complete susceptibility were observed in a large collection of B. distachyon (2n=2x=10) and B. hybridum (2n=4x=30) accessions inoculated with four of the C. sativus isolates. Evaluation of an F2 population derived from the cross between two of the B. distachyon lines, Bd1-1 and Bd3-1, with isolate Cs07-47-1 showed quantitative and transgressive segregation for resistance to C. sativus, suggesting that the resistance may be governed by quantitative trait loci from both parents. The availability of whole-genome sequences of both the host (B. distachyon) and the pathogen (C. sativus) makes this pathosystem an attractive model for studying this important disease of cereal crops.

  12. Final technical report for: Insertional Mutagenesis of Brachypodium distachyon DE-AI02-07ER64452

    Energy Technology Data Exchange (ETDEWEB)

    John, Vogel P. [DOE Joint Genome Institute, Walnut Creek, CA (United States)

    2015-10-29

    Several bioenergy grasses are poised to become a major source of energy in the United States. Despite their increasing importance, we know little about the basic biology underlying the traits that control the utility of grasses as energy crops. Better knowledge of grass biology (e.g. identification of the genes that control cell wall composition, plant architecture, cell size, cell division, reproduction, nutrient uptake, carbon flux, etc.) could be used to design rational strategies for crop improvement and shorten the time required to domesticate these species. The use of an appropriate model system is an efficient way to gain this knowledge. Brachypodium distachyon is a small annual grass with all the attributes needed to be a modern model organism including simple growth requirements, fast generation time, small stature, small genome size and self-fertility. These attributes led to the recommendation in the DOE’s “Breaking the Biological Barriers to Cellulosic Ethanol: A Joint Research Agenda” report to propose developing and using B. distachyon as a model for energy crops to accelerate their domestication. Strategic investments (e.g. genome sequencing) in B. distachyon by the DOE are now bearing fruit and B. distachyon is being used as a model grass by hundreds of laboratories worldwide. Sequence indexed insertional mutants are an extremely powerful tool for both forward and reverse genetics. They allow researchers to order mutants in any gene tagged in the collection by simply emailing a request. The goal of this project was to create a collection of sequence indexed insertional mutants (T-DNA lines) for the model grass Brachypodium distachyon in order to facilitate research by the scientific community. During the course of this grant we created a collection of 23,649 B. distachyon T-DNA lines and identified 26,112 unique insertion sites. The collection can be queried through the project website (http://jgi.doe.gov/our-science/science-programs/plant-genomics/brachypodium/brachypodium

  13. Evaluation of Brachypodium distachyon L-Tyrosine Decarboxylase Using L-Tyrosine Over-Producing Saccharomyces cerevisiae.

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    Shuhei Noda

    Full Text Available To demonstrate that herbaceous biomass is a versatile gene resource, we focused on the model plant Brachypodium distachyon, and screened the B. distachyon for homologs of tyrosine decarboxylase (TDC, which is involved in the modification of aromatic compounds. A total of 5 candidate genes were identified in cDNA libraries of B. distachyon and were introduced into Saccharomyces cerevisiae to evaluate TDC expression and tyramine production. It is suggested that two TDCs encoded in the transcripts Bradi2g51120.1 and Bradi2g51170.1 have L-tyrosine decarboxylation activity. Bradi2g51170.1 was introduced into the L-tyrosine over-producing strain of S. cerevisiae that was constructed by the introduction of mutant genes that promote deregulated feedback inhibition. The amount of tyramine produced by the resulting transformant was 6.6-fold higher (approximately 200 mg/L than the control strain, indicating that B. distachyon TDC effectively converts L-tyrosine to tyramine. Our results suggest that B. distachyon possesses enzymes that are capable of modifying aromatic residues, and that S. cerevisiae is a suitable host for the production of L-tyrosine derivatives.

  14. Daily changes in temperature, not the circadian clock, regulate growth rate in Brachypodium distachyon.

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    Dominick A Matos

    Full Text Available Plant growth is commonly regulated by external cues such as light, temperature, water availability, and internal cues generated by the circadian clock. Changes in the rate of growth within the course of a day have been observed in the leaves, stems, and roots of numerous species. However, the relative impact of the circadian clock on the growth of grasses has not been thoroughly characterized. We examined the influence of diurnal temperature and light changes, and that of the circadian clock on leaf length growth patterns in Brachypodium distachyon using high-resolution time-lapse imaging. Pronounced changes in growth rate were observed under combined photocyles and thermocycles or with thermocycles alone. A considerably more rapid growth rate was observed at 28°C than 12°C, irrespective of the presence or absence of light. In spite of clear circadian clock regulated gene expression, plants exhibited no change in growth rate under conditions of constant light and temperature, and little or no effect under photocycles alone. Therefore, temperature appears to be the primary cue influencing observed oscillations in growth rate and not the circadian clock or photoreceptor activity. Furthermore, the size of the leaf meristem and final cell length did not change in response to changes in temperature. Therefore, the nearly five-fold difference in growth rate observed across thermocycles can be attributed to proportionate changes in the rate of cell division and expansion. A better understanding of the growth cues in B. distachyon will further our ability to model metabolism and biomass accumulation in grasses.

  15. Daily changes in temperature, not the circadian clock, regulate growth rate in Brachypodium distachyon.

    Science.gov (United States)

    Matos, Dominick A; Cole, Benjamin J; Whitney, Ian P; MacKinnon, Kirk J-M; Kay, Steve A; Hazen, Samuel P

    2014-01-01

    Plant growth is commonly regulated by external cues such as light, temperature, water availability, and internal cues generated by the circadian clock. Changes in the rate of growth within the course of a day have been observed in the leaves, stems, and roots of numerous species. However, the relative impact of the circadian clock on the growth of grasses has not been thoroughly characterized. We examined the influence of diurnal temperature and light changes, and that of the circadian clock on leaf length growth patterns in Brachypodium distachyon using high-resolution time-lapse imaging. Pronounced changes in growth rate were observed under combined photocyles and thermocycles or with thermocycles alone. A considerably more rapid growth rate was observed at 28°C than 12°C, irrespective of the presence or absence of light. In spite of clear circadian clock regulated gene expression, plants exhibited no change in growth rate under conditions of constant light and temperature, and little or no effect under photocycles alone. Therefore, temperature appears to be the primary cue influencing observed oscillations in growth rate and not the circadian clock or photoreceptor activity. Furthermore, the size of the leaf meristem and final cell length did not change in response to changes in temperature. Therefore, the nearly five-fold difference in growth rate observed across thermocycles can be attributed to proportionate changes in the rate of cell division and expansion. A better understanding of the growth cues in B. distachyon will further our ability to model metabolism and biomass accumulation in grasses.

  16. Comparative genome analysis between Agrostis stolonifera and members of the Pooideae subfamily, including Brachypodium distachyon.

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    Loreto Araneda

    Full Text Available Creeping bentgrass (Agrostis stolonifera, allotetraploid 2n = 4x = 28 is one of the major cool-season turfgrasses. It is widely used on golf courses due to its tolerance to low mowing and aggressive growth habit. In this study, we investigated genome relationships of creeping bentgrass relative to the Triticeae (a consensus map of Triticum aestivum, T. tauschii, Hordeum vulgare, and H. spontaneum, oat, rice, and ryegrass maps using a common set of 229 EST-RFLP markers. The genome comparisons based on the RFLP markers revealed large-scale chromosomal rearrangements on different numbers of linkage groups (LGs of creeping bentgrass relative to the Triticeae (3 LGs, oat (4 LGs, and rice (8 LGs. However, we detected no chromosomal rearrangement between creeping bentgrass and ryegrass, suggesting that these recently domesticated species might be closely related, despite their memberships to different Pooideae tribes. In addition, the genome of creeping bentgrass was compared with the complete genome sequence of Brachypodium distachyon in Pooideae subfamily using both sequences of the above-mentioned mapped EST-RFLP markers and sequences of 8,470 publicly available A. stolonifera ESTs (AgEST. We discovered large-scale chromosomal rearrangements on six LGs of creeping bentgrass relative to B. distachyon. Also, a total of 24 syntenic blocks based on 678 orthologus loci were identified between these two grass species. The EST orthologs can be utilized in further comparative mapping of Pooideae species. These results will be useful for genetic improvement of Agrostis species and will provide a better understanding of evolution within Pooideae species.

  17. CG Methylation Covaries with Differential Gene Expression between Leaf and Floral Bud Tissues of Brachypodium distachyon.

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    Kyria Roessler

    Full Text Available DNA methylation has the potential to influence plant growth and development through its influence on gene expression. To date, however, the evidence from plant systems is mixed as to whether patterns of DNA methylation vary significantly among tissues and, if so, whether these differences affect tissue-specific gene expression. To address these questions, we analyzed both bisulfite sequence (BSseq and transcriptomic sequence data from three biological replicates of two tissues (leaf and floral bud from the model grass species Brachypodium distachyon. Our first goal was to determine whether tissues were more differentiated in DNA methylation than explained by variation among biological replicates. Tissues were more differentiated than biological replicates, but the analysis of replicated data revealed high (>50% false positive rates for the inference of differentially methylated sites (DMSs and differentially methylated regions (DMRs. Comparing methylation to gene expression, we found that differential CG methylation consistently covaried negatively with gene expression, regardless as to whether methylation was within genes, within their promoters or even within their closest transposable element. The relationship between gene expression and either CHG or CHH methylation was less consistent. In total, CG methylation in promoters explained 9% of the variation in tissue-specific expression across genes, suggesting that CG methylation is a minor but appreciable factor in tissue differentiation.

  18. Digital imaging approaches for phenotyping whole plant nitrogen and phosphorus response in Brachypodium distachyon

    Institute of Scientific and Technical Information of China (English)

    Richard Poir; Vincent Chochois; Xavier R.R.Sirault; John P.Vogel; Michelle Watt; Robert T.Furbank

    2014-01-01

    This work evaluates the phenotypic response of the model grass (Brachypodium distachyon (L.) P. Beauv.) to nitrogen and phosphorus nutrition using a combination of imaging techniques and destructive harvest of shoots and roots. Reference line Bd21-3 was grown in pots using 11 phosphorus and 11 nitrogen concentrations to establish a dose-response curve. Shoot biovolume and biomass, root length and biomass, and tissue phosphorus and nitrogen concentrations increased with nutrient concentration. Shoot biovolume, estimated by imaging, was highly correlated with dry weight (R2>0.92) and both biovolume and growth rate responded strongly to nutrient availability. Higher nutrient supply increased nodal root length more than other root types. Photochemical efficiency was strongly reduced by low phosphorus concentrations as early as 1 week after germination, suggesting that this measurement may be suitable for high throughput screening of phosphorus response. In contrast, nitrogen concentration had little effect on photochemical efficiency. Changes in biovolume over time were used to compare growth rates of four accessions in response to nitrogen and phosphorus supply. We demonstrate that a time series image-based approach coupled with mathematical modeling provides higher resolution of genotypic response to nutrient supply than traditional destructive techniques and shows promise for high throughput screening and determina-tion of genomic regions associated with superior nutrient use efficiency.

  19. Accelerated Growth Rate and Increased Drought Stress Resilience of the Model Grass Brachypodium distachyon Colonized by Bacillus subtilis B26.

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    François Gagné-Bourque

    Full Text Available Plant growth-promoting bacteria (PGB induce positive effects in plants, for instance, increased growth and reduced abiotic stresses susceptibility. The mechanisms by which these bacteria impact the host plant are numerous, diverse and often specific. Here, we studied the agronomical, molecular and biochemical effects of the endophytic PGB Bacillus subtilis B26 on the full life cycle of Brachypodium distachyon Bd21, an established model species for functional genomics in cereal crops and temperate grasses. Inoculation of Brachypodium with B. subtilis strain B26 increased root and shoot weights, accelerated growth rate and seed yield as compared to control plants. B. subtilis strain B26 efficiently colonized the plant and was recovered from roots, stems and blades as well as seeds of Brachypodium, indicating that the bacterium is able to migrate, spread systemically inside the plant, establish itself in the aerial plant tissues and organs, and is vertically transmitted to seeds. The presence of B. subtilis strain B26 in the seed led to systemic colonization of the next generation of Brachypodium plants. Inoculated Brachypodium seedlings and mature plants exposed to acute and chronic drought stress minimized the phenotypic effect of drought compared to plants not harbouring the bacterium. Protection from the inhibitory effects of drought by the bacterium was linked to upregulation of the drought-response genes, DREB2B-like, DHN3-like and LEA-14-A-like and modulation of the DNA methylation genes, MET1B-like, CMT3-like and DRM2-like, that regulate the process. Additionally, total soluble sugars and starch contents increased in stressed inoculated plants, a biochemical indication of drought tolerance. In conclusion, we show a single inoculation of Brachypodium with a PGB affected the whole growth cycle of the plant, accelerating its growth rates, shortening its vegetative period, and alleviating drought stress effects. These effects are relevant to

  20. Final technical report for Phenomic Analysis of Natural and Induced Variation in Brachypodium Distachyon DE-SC0001526

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, John P. [USDA ARS Western Regional Research Center, Albany, NY (United States)

    2014-12-17

    The goal of this project was to apply high-throughput, non-destructive phenotyping (phenomics) to collections of natural variants and induced mutants of the model grass Brachypodium distachyon and characterize a small subset of that material in detail. B. distachyon is well suited to this phenomic approach because its small size and rapid generation time allow researchers to grow many plants under carefully controlled conditions. In addition, the simple diploid genetics, high quality genome sequence and existence of numerous experimental tools available for B. distachyon allow us to rapidly identify genes affecting specific phenotypes. Our phenomic analysis revealed great diversity in biofuel-relevant traits like growth rate, biomass and photosynthetic rate. This clearly demonstrated the feasibility of applying a phenomic approach to the model grass B. distachyon. We also demonstrated the utility of B. distachyon for studying mature root system, something that is virtually impossible to do with biomass crops. We showed tremendous natural variation in root architecture that can potentially be used to design crops with superior nutrient and water harvesting capability. Finally, we demonstrated the speed with which we can link specific genes to specific phenotypes by studying two mutants in detail. Importantly, in both cases, the specific biological lessons learned were grass-specific and could not have been learned from a dicot model system. Furthermore, one of the genes affects cell wall integrity and thus may be a useful target in the context of biomass crop improvement. Ultimately, all this information can be used to accelerate the creation of improved biomass crops.

  1. Functional conservation and diversification of APETALA1/FRUITFULL genes in Brachypodium distachyon.

    Science.gov (United States)

    Li, Qi; Wang, Ye; Wang, Fuxiang; Guo, Yuyu; Duan, Xueqing; Sun, Jinhao; An, Hailong

    2016-08-01

    The duplicated grass APETALA1/FRUITFULL (AP1/FUL) genes have distinct but overlapping patterns of expression, suggesting their discrete roles in transition to flowering, specification of spikelet meristem identity and specification of floral organ identity. In this study, we analyzed the expression patterns and functions of four AP1/FUL paralogs (BdVRN1, BdFUL2, BdFUL3 and BdFUL4) in Brachypodium distachyon, a model plant for the temperate cereals and related grasses. Among the four genes tested, only BdVRN1 could remember the prolonged cold treatment. The recently duplicated BdVRN1 and BdFUL2 genes were expressed in a highly consistent manner and ectopic expressions of them caused similar phenotypes such as extremely early flowering and severe morphological alterations of floral organs, indicating their redundant roles in floral transition, inflorescence development and floral organ identity. In comparison, ectopic expressions of BdFUL3 and BdFUL4 only caused a moderate early flowering phenotype, suggesting their divergent function. In yeast two-hybrid assay, both BdVRN1 and BdFUL2 physically interact with SEP proteins but only BdFUL2 is able to form a homodimer. BdVRN1 also interacts weakly with BdFUL2. Our results indicate that, since the separation of AP1/FUL genes in grasses, the process of sub- or neo-functionalization has occurred and paralogs function redundantly and/or separately in flowering competence and inflorescence development.

  2. Brachypodium distachyon – A Useful Model in the Qualification of Mutagen-Induced Micronuclei Using Multicolor FISH

    Science.gov (United States)

    Kus, Arita; Kwasniewska, Jolanta; Hasterok, Robert

    2017-01-01

    Brachypodium distachyon (Brachypodium) is now intensively utilized as a model grass species in various biological studies. Its favorable cytological features create a unique foundation for a convenient system in mutagenesis, thereby potentially enabling the ‘hot spots’ and ‘cold spots’ of DNA damage in its genome to be analyzed. The aim of this study was to analyze the involvement of 5S rDNA, 25S rDNA, the Arabidopsis-type (TTTAGGG)n telomeric sequence and the Brachypodium-originated centromeric BAC clone CB33J12 in the micronuclei formation in Brachypodium root tip cells that were subjected to the chemical clastogenic agent maleic hydrazide (MH). To the best of our knowledge, this is the first use of a multicolor fluorescence in situ hybridization (mFISH) with four different DNA probes being used simultaneously to study plant mutagenesis. A quantitative analysis allowed ten types of micronuclei, which were characterized by the presence or absence of specific FISH signal(s), to be distinguished, thus enabling some specific rules governing the composition of the MH-induced micronuclei with the majority of them originating from the terminal regions of chromosomes, to be identified. The application of rDNA sequences as probes showed that 5S rDNA-bearing chromosomes are involved in micronuclei formation more frequently than the 25S rDNA-bearing chromosomes. These findings demonstrate the promising potential of Brachypodium to be a useful model organism to analyze the effects of various genotoxic agents on the plant nuclear genome stability, especially when the complex FISH-based and chromosome-specific approaches such as chromosome barcoding and chromosome painting will be applied in future studies. PMID:28118403

  3. Analysis of global gene expression in Brachypodium distachyon reveals extensive network plasticity in response to abiotic stress.

    Directory of Open Access Journals (Sweden)

    Henry D Priest

    Full Text Available Brachypodium distachyon is a close relative of many important cereal crops. Abiotic stress tolerance has a significant impact on productivity of agriculturally important food and feedstock crops. Analysis of the transcriptome of Brachypodium after chilling, high-salinity, drought, and heat stresses revealed diverse differential expression of many transcripts. Weighted Gene Co-Expression Network Analysis revealed 22 distinct gene modules with specific profiles of expression under each stress. Promoter analysis implicated short DNA sequences directly upstream of module members in the regulation of 21 of 22 modules. Functional analysis of module members revealed enrichment in functional terms for 10 of 22 network modules. Analysis of condition-specific correlations between differentially expressed gene pairs revealed extensive plasticity in the expression relationships of gene pairs. Photosynthesis, cell cycle, and cell wall expression modules were down-regulated by all abiotic stresses. Modules which were up-regulated by each abiotic stress fell into diverse and unique gene ontology GO categories. This study provides genomics resources and improves our understanding of abiotic stress responses of Brachypodium.

  4. Fine mapping of the Bsr1 barley stripe mosaic virus resistance gene in the model grass Brachypodium distachyon.

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    Yu Cui

    Full Text Available The ND18 strain of Barley stripe mosaic virus (BSMV infects several lines of Brachypodium distachyon, a recently developed model system for genomics research in cereals. Among the inbred lines tested, Bd3-1 is highly resistant at 20 to 25 °C, whereas Bd21 is susceptible and infection results in an intense mosaic phenotype accompanied by high levels of replicating virus. We generated an F(6:7 recombinant inbred line (RIL population from a cross between Bd3-1 and Bd21 and used the RILs, and an F(2 population of a second Bd21 × Bd3-1 cross to evaluate the inheritance of resistance. The results indicate that resistance segregates as expected for a single dominant gene, which we have designated Barley stripe mosaic virus resistance 1 (Bsr1. We constructed a genetic linkage map of the RIL population using SNP markers to map this gene to within 705 Kb of the distal end of the top of chromosome 3. Additional CAPS and Indel markers were used to fine map Bsr1 to a 23 Kb interval containing five putative genes. Our study demonstrates the power of using RILs to rapidly map the genetic determinants of BSMV resistance in Brachypodium. Moreover, the RILs and their associated genetic map, when combined with the complete genomic sequence of Brachypodium, provide new resources for genetic analyses of many other traits.

  5. Quantitative trait loci associated with natural diversity in water-use efficiency and response to soil drying in Brachypodium distachyon.

    Science.gov (United States)

    Des Marais, David L; Razzaque, Samsad; Hernandez, Kyle M; Garvin, David F; Juenger, Thomas E

    2016-10-01

    All plants must optimize their growth with finite resources. Water use efficiency (WUE) measures the relationship between biomass acquisition and transpired water. In the present study, we performed two experiments to understand the genetic basis of WUE and other parameters of plant-water interaction under control and water-limited conditions. Our study used two inbred natural accessions of Brachypodium distachyon, a model grass species with close phylogenetic affinity to temperate forage and cereal crops. First, we identify the soil water content which causes a reduction in leaf relative water content and an increase in WUE. Second, we present results from a large phenotyping experiment utilizing a recombinant inbred line mapping population derived from these same two natural accessions. We identify QTLs associated with environmentally-insensitive genetic variation in WUE, including a pair of epistatically interacting loci. We also identify QTLs associated with constitutive differences in biomass and a QTL describing an environmentally-sensitive difference in leaf carbon content. Finally, we present a new linkage map for this mapping population based on new SNP markers as well as updated genomic positions for previously described markers. Our studies provide an initial characterization of plant-water relations in B. distachyon and identify candidate genomic regions involved in WUE.

  6. Addressing the Role of microRNAs in Reprogramming Leaf Growth during Drought Stress in Brachypodium distachyon

    Institute of Scientific and Technical Information of China (English)

    Edoardo Bertolini; Wim Verelst; David Stephen Horner; Luca Gianfranceschi; Viviana Piccolo; Dirk Inzé; Mario Enrico Pè

    2013-01-01

    Plant responses to drought are regulated by complex genetic and epigenetic networks leading to rapid reprogramming of plant growth,miRNAs have been widely indicated as key players in the regulation of growth and development.The role of miRNAs in drought response was investigated in young leaves of Brachypodium distachyon,a drought-tolerant monocot model species.Adopting an in vivo drought assay,shown to cause a dramatic reduction in leaf size,mostly due to reduced cell expansion,small RNA libraries were produced from proliferating and expanding leaf cells.Next-generation sequencing data were analyzed using an in-house bioinformatics pipeline allowing the identification of 66 annotated miRNA genes and 122 new high confidence predictions greatly expanding the number of known Brachypodium miRNAs.In addition,we identified four TAS3 loci and a large number of siRNA-producing loci that show characteristics suggesting that they may represent young miRNA genes.Most miRNAs showed a high expression level,consistent with their involvement in early leaf development and cell identity.Proliferating and expanding leaf cells respond differently to drought treatment and differential expression analyses suggest novel evidence for an miRNA regulatory network controlling cell division in both normal and stressed conditions and demonstrate that drought triggers a genetic reprogramming of leaf growth in which miRNAs are deeply involved.

  7. Investigations of barley stripe mosaic virus as a gene silencing vector in barley roots and in Brachypodium distachyon and oat

    Directory of Open Access Journals (Sweden)

    Nilsson Lena

    2010-11-01

    Full Text Available Abstract Background Gene silencing vectors based on Barley stripe mosaic virus (BSMV are used extensively in cereals to study gene function, but nearly all studies have been limited to genes expressed in leaves of barley and wheat. However since many important aspects of plant biology are based on root-expressed genes we wanted to explore the potential of BSMV for silencing genes in root tissues. Furthermore, the newly completed genome sequence of the emerging cereal model species Brachypodium distachyon as well as the increasing amount of EST sequence information available for oat (Avena species have created a need for tools to study gene function in these species. Results Here we demonstrate the successful BSMV-mediated virus induced gene silencing (VIGS of three different genes in barley roots, i.e. the barley homologues of the IPS1, PHR1, and PHO2 genes known to participate in Pi uptake and reallocation in Arabidopsis. Attempts to silence two other genes, the Pi transporter gene HvPht1;1 and the endo-β-1,4-glucanase gene HvCel1, in barley roots were unsuccessful, probably due to instability of the plant gene inserts in the viral vector. In B. distachyon leaves, significant silencing of the PHYTOENE DESATURASE (BdPDS gene was obtained as shown by photobleaching as well as quantitative RT-PCR analysis. On the other hand, only very limited silencing of the oat AsPDS gene was observed in both hexaploid (A. sativa and diploid (A. strigosa oat. Finally, two modifications of the BSMV vector are presented, allowing ligation-free cloning of DNA fragments into the BSMV-γ component. Conclusions Our results show that BSMV can be used as a vector for gene silencing in barley roots and in B. distachyon leaves and possibly roots, opening up possibilities for using VIGS to study cereal root biology and to exploit the wealth of genome information in the new cereal model plant B. distachyon. On the other hand, the silencing induced by BSMV in oat seemed too

  8. Imaging with the fluorogenic dye Basic Fuchsin reveals subcellular patterning and ecotype variation of lignification in Brachypodium distachyon

    Science.gov (United States)

    Kapp, Nikki; Barnes, William J.; Richard, Tom L.; Anderson, Charles T.

    2015-01-01

    Lignin is a complex polyphenolic heteropolymer that is abundant in the secondary cell walls of plants and functions in growth and defence. It is also a major barrier to the deconstruction of plant biomass for bioenergy production, but the spatiotemporal details of how lignin is deposited in actively lignifying tissues and the precise relationships between wall lignification in different cell types and developmental events, such as flowering, are incompletely understood. Here, the lignin-detecting fluorogenic dye, Basic Fuchsin, was adapted to enable comparative fluorescence-based imaging of lignin in the basal internodes of three Brachypodium distachyon ecotypes that display divergent flowering times. It was found that the extent and intensity of Basic Fuchsin fluorescence increase over time in the Bd21-3 ecotype, that Basic Fuchsin staining is more widespread and intense in 4-week-old Bd21-3 and Adi-10 basal internodes than in Bd1-1 internodes, and that Basic Fuchsin staining reveals subcellular patterns of lignin in vascular and interfascicular fibre cell walls. Basic Fuchsin fluorescence did not correlate with lignin quantification by acetyl bromide analysis, indicating that whole-plant and subcellular lignin analyses provide distinct information about the extent and patterns of lignification in B. distachyon. Finally, it was found that flowering time correlated with a transient increase in total lignin, but did not correlate strongly with the patterning of stem lignification, suggesting that additional developmental pathways might regulate secondary wall formation in grasses. This study provides a new comparative tool for imaging lignin in plants and helps inform our views of how lignification proceeds in grasses. PMID:25922482

  9. Gene space dynamics during the evolution of Aegilops tauschii, Brachypodium distachyon, Oryza sativa, and Sorghum bicolor genomes.

    Science.gov (United States)

    Massa, A N; Wanjugi, H; Deal, K R; O'Brien, K; You, F M; Maiti, R; Chan, A P; Gu, Y Q; Luo, M C; Anderson, O D; Rabinowicz, P D; Dvorak, J; Devos, K M

    2011-09-01

    Nine different regions totaling 9.7 Mb of the 4.02 Gb Aegilops tauschii genome were sequenced using the Sanger sequencing technology and compared with orthologous Brachypodium distachyon, Oryza sativa (rice), and Sorghum bicolor (sorghum) genomic sequences. The ancestral gene content in these regions was inferred and used to estimate gene deletion and gene duplication rates along each branch of the phylogenetic tree relating the four species. The total gene number in the extant Ae. tauschii genome was estimated to be 36,371. The gene deletion and gene duplication rates and total gene numbers in the four genomes were used to estimate the total gene number in each node of the phylogenetic tree. The common ancestor of the Brachypodieae and Triticeae lineages was estimated to have had 28,558 genes, and the common ancestor of the Panicoideae, Ehrhartoideae, and Pooideae subfamilies was estimated to have had 27,152 or 28,350 genes, depending on the ancestral gene scenario. Relative to the Brachypodieae and Triticeae common ancestor, the gene number was reduced in B. distachyon by 3,026 genes and increased in Ae. tauschii by 7,813 genes. The sum of gene deletion and gene duplication rates, which reflects the rate of gene synteny loss, was correlated with the rate of structural chromosome rearrangements and was highest in the Ae. tauschii lineage and lowest in the rice lineage. The high rate of gene space evolution in the Ae. tauschii lineage accounts for the fact that, contrary to the expectations, the level of synteny between the phylogenetically more related Ae. tauschii and B. distachyon genomes is similar to the level of synteny between the Ae. tauschii genome and the genomes of the less related rice and sorghum. The ratio of gene duplication to gene deletion rates in these four grass species closely parallels both the total number of genes in a species and the overall genome size. Because the overall genome size is to a large extent a function of the repeated

  10. Identification of genes that regulate phosphate acquisition and plant performance during arbuscular my corrhizal symbiosis in medicago truncatula and brachypodium distachyon

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Maria J [Boyce Thompson Institute, Ithaca, NY (United States); Hudson, Matthew E [Univ. of Illinois, Champaign, IL (United States)

    2015-11-24

    Most vascular flowering plants have the ability to form symbiotic associations with arbuscular mycorrhizal (AM) fungi. The symbiosis develops in the roots and can have a profound effect on plant productivity, largely through improvements in plant mineral nutrition. Within the root cortical cells, the plant and fungus create novel interfaces specialized for nutrient transfer, while the fungus also develops a network of hyphae in the rhizosphere. Through this hyphal network, the fungus acquires and delivers phosphate and nitrogen to the root. In return, the plant provides the fungus with carbon. In addition, to enhancing plant mineral nutrition, the AM symbiosis has an important role in the carbon cycle, and positive effects on soil health. Here we identified and characterized plant genes involved in the regulation and functioning of the AM symbiosis in Medicago truncatula and Brachypodium distachyon. This included the identification and and characterization of a M. truncatula transcription factors that are required for symbiosis. Additionally, we investigated the molecular basis of functional diversity among AM symbioses in B. distachyon and analysed the transcriptome of Brachypodium distachyon during symbiosis.

  11. In silico sequence analysis and homology modeling of predicted beta-amylase 7-like protein in Brachypodium distachyon L.

    Directory of Open Access Journals (Sweden)

    ERTUĞRUL FILIZ

    2014-04-01

    Full Text Available Beta-amylase (β-amylase, EC 3.2.1.2 is an enzyme that catalyses hydrolysis of glucosidic bonds in polysaccharides. In this study, we analyzed protein sequence of predicted beta-amylase 7-like protein in Brachypodium distachyon. pI (isoelectric point value was found as 5.23 in acidic character, while the instability index (II was found as 50.28 with accepted unstable protein. The prediction of subcellular localization was revealed that the protein may reside in chloroplast by using CELLO v.2.5. The 3D structure of protein was performed using comparative homology modeling with SWISS-MODEL. The accuracy of the predicted 3D structure was checked using Ramachandran plot analysis showed that 95.4% in favored region. The results of our study contribute to understanding of β-amylase protein structure in grass species and will be scientific base for 3D modeling of beta-amylase proteins in further studies.

  12. Integrative proteome analysis of Brachypodium distachyon roots and leaves reveals a synergetic responsive network under H2O2 stress.

    Science.gov (United States)

    Bian, Yan-Wei; Lv, Dong-Wen; Cheng, Zhi-Wei; Gu, Ai-Qin; Cao, Hui; Yan, Yue-Ming

    2015-10-14

    The plant oxidative stress response is vital for defense against various abiotic and biotic stresses. In this study, ultrastructural changes and the proteomic response to H2O2 stress in roots and leaves of the model plant Brachypodium distachyon were studied. Transmission electron microscopy (TEM) showed that the ultrastructural damage in roots was more serious than in leaves. Particularly, the ultrastructures of organelles and the nucleus in root tip cells were damaged, leading to the inhibition of normal biological activities of roots, which then spread throughout the plant. Based on two-dimensional electrophoresis (2-DE) and MALDI-TOF/TOF-MS, 84 and 53 differentially accumulated protein (DAP) spots representing 75 and 45 unique proteins responsive to H2O2 stress in roots and leaves, respectively, were identified. These protein species were mainly involved in signal transduction, energy metabolism, redox homeostasis/stress defense, protein folding/degradation, and cell wall/cell structure. Interestingly, two 14-3-3 proteins (GF14-B and GF14-D) were identified as DAPs in both roots and leaves. Protein-protein interaction (PPI) analysis revealed a synergetic H2O2-responsive network.

  13. Analysis of two heterologous flowering genes in ¤Brachypodium distachyon¤ demonstrates its potential as a grass model plant

    DEFF Research Database (Denmark)

    Olsen, P.; Lenk, I.; Jensen, Christian S.

    2006-01-01

    date up to 10 weeks in plants of the T, generation. Furthermore, a positive correlation between Terminal Flower 1 expression level and delay in heading date was apparent for most of the lines. The short life cycle and fast transformation system of B. distachyon allowed heading date analyses in the T-1......Despite the great contribution of model organisms, such as Arabidopsis and rice to understand biological processes in plants, these models are less valuable for functional studies of particular genes from temperate grass crop species. Therefore a new model plant is required, displaying features...... including close phylogenetic relationship to the temperate grasses, vernalisation requirement, high transformation efficiency, small genome size and a rapid life cycle. These requirements are all fulfilled by the small annual grass Brachypodium distachyon. As a first step towards implementing this plant...

  14. Evaluation of the use of the polyubiquitin genes, Ubi4 and Ubi10 as reference genes for expression studies in Brachypodium distachyon.

    Directory of Open Access Journals (Sweden)

    John P Chambers

    Full Text Available BACKGROUND: Brachypodium distachyon is emerging as the model plant for temperate grass research and the genome of the community line Bd21 has been sequenced. Additionally, techniques have been developed for Agrobacterium-mediated transformation for the generation of T-DNA insertional lines. Recently, it was reported that expression of the polyubiquitin genes, Ubi4 and Ubi10 are stable in different tissues and growth hormone-treated plant samples, leading to the conclusion that both Ubi4 and Ubi10 are good reference genes for normalization of gene expression data using real-time, quantitative PCR (qPCR. PRINCIPAL FINDINGS: Mining of the Joint Genome Institute (JGI 8X Brachypodium distachyon genome assembly showed that Ubi4 and Ubi10 share a high level of sequence identity (89%, and in silico analyses of the sequences of Ubi4 (Bradi3g04730 and Ubi10 (Bradi1g32860 showed that the primers used previously exhibit multiple binding sites within the coding sequences arising from the presence of tandem repeats of the coding regions. This can potentially result in over-estimation of steady-state levels of Ubi4 and Ubi10. Additionally, due to the high level of sequence identity between both genes, primers used previously for amplification of Ubi4 can bind to Ubi10 and vice versa, resulting in the formation of non-specific amplification products. CONCLUSIONS: The results from this study indicate that the primers used previously were not sufficiently robust and specific. Additionally, their use would result in over-estimation of the steady-state expression levels of Ubi4. Our results question the validity of using the previously proposed primer sets for qPCR amplification of Ubi4 and Ubi10. We demonstrate that primers designed to target the 3'-UTRs of Ubi4 and Ubi10 are better suited for real-time normalization of steady-state expression levels in Brachypodium distachyon.

  15. A high-throughput Agrobacterium-mediated transformation system for the grass model species Brachypodium distachyon L.

    Science.gov (United States)

    Păcurar, Daniel Ioan; Thordal-Christensen, Hans; Nielsen, Klaus Kristian; Lenk, Ingo

    2008-10-01

    In the ongoing process of developing Brachypodium distachyon as a model plant for temperate cereals and forage grasses, we have developed a high-throughput Agrobacterium-mediated transformation system for a diploid accession. Embryogenic callus, derived from immature embryos of the accession BDR018, were transformed with Agrobacterium tumefaciens strain AGL1 carrying two T-DNA plasmids, pDM805 and pWBV-Ds-Ubi-bar-Ds. Transient and stable transformation efficiencies were optimised by varying the pre-cultivation period, which had a strong effect on stable transformation efficiency. On average 55% of 17-day-old calli co-inoculated with Agrobacterium regenerated stable transgenic plants. Stable transformation frequencies of up to 80%, which to our knowledge is the highest transformation efficiency reported in graminaceous species, were observed. In a study of 177 transgenic lines transformed with pDM805, all of the regenerated transgenic lines were resistant to BASTA, while the gusA gene was expressed in 88% of the transgenic lines. Southern blot analysis revealed that 35% of the tested plants had a single T-DNA integration. Segregation analysis performed on progenies of ten selected T(0) plants indicated simple Mendelian inheritance of the two transgenes. Furthermore, the presence of two selection marker genes, bar and hpt, on the T-DNA of pWBV-Ds-Ubi-bar-Ds allowed us to characterize the developed transformation protocol with respect to full-length integration rate. Even when not selected for, full-length integration occurred in 97% of the transformants when using bialaphos as selection agent.

  16. A DNA barcoding method to discriminate between the model plant Brachypodium distachyon and its close relatives B. stacei and B. hybridum (Poaceae.

    Directory of Open Access Journals (Sweden)

    Diana López-Alvarez

    Full Text Available BACKGROUND: Brachypodium distachyon s. l. has been widely investigated across the world as a model plant for temperate cereals and biofuel grasses. However, this annual plant shows three cytotypes that have been recently recognized as three independent species, the diploids B. distachyon (2n = 10 and B. stacei (2n = 20 and their derived allotetraploid B. hybridum (2n = 30. METHODOLOGY/PRINCIPAL FINDINGS: We propose a DNA barcoding approach that consists of a rapid, accurate and automatable species identification method using the standard DNA sequences of complementary plastid (trnLF and nuclear (ITS, GI loci. The highly homogenous but largely divergent B. distachyon and B. stacei diploids could be easily distinguished (100% identification success using direct trnLF (2.4%, ITS (5.5% or GI (3.8% sequence divergence. By contrast, B. hybridum could only be unambiguously identified through the use of combined trnLF+ITS sequences (90% of identification success or by cloned GI sequences (96.7% that showed 5.4% (ITS and 4% (GI rate divergence between the two parental sequences found in the allopolyploid. CONCLUSION/SIGNIFICANCE: Our data provide an unbiased and effective barcode to differentiate these three closely-related species from one another. This procedure overcomes the taxonomic uncertainty generated from methods based on morphology or flow cytometry identifications that have resulted in some misclassifications of the model plant and its allies. Our study also demonstrates that the allotetraploid B. hybridum has resulted from bi-directional crosses of B. distachyon and B. stacei plants acting either as maternal or paternal parents.

  17. High-Throughput Sequencing Reveals H2O2 Stress-Associated MicroRNAs and a Potential Regulatory Network in Brachypodium distachyon Seedlings

    Science.gov (United States)

    Lv, Dong-Wen; Zhen, Shoumin; Zhu, Geng-Rui; Bian, Yan-Wei; Chen, Guan-Xing; Han, Cai-Xia; Yu, Zi-Tong; Yan, Yue-Ming

    2016-01-01

    Oxidative stress in plants can be triggered by many environmental stress factors, such as drought and salinity. Brachypodium distachyon is a model organism for the study of biofuel plants and crops, such as wheat. Although recent studies have found many oxidative stress response-related proteins, the mechanism of microRNA (miRNA)-mediated oxidative stress response is still unclear. Using next generation high-throughput sequencing technology, the small RNAs were sequenced from the model plant B. distachyon 21 (Bd21) under H2O2 stress and normal growth conditions. In total, 144 known B. distachyon miRNAs and 221 potential new miRNAs were identified. Further analysis of potential new miRNAs suggested that 36 could be clustered into known miRNA families, while the remaining 185 were identified as B. distachyon-specific new miRNAs. Differential analysis of miRNAs from the normal and H2O2 stress libraries identified 31 known and 30 new H2O2 stress responsive miRNAs. The expression patterns of seven representative miRNAs were verified by reverse transcription quantitative polymerase chain reaction (RT-qPCR) analysis, which produced results consistent with those of the deep sequencing method. Moreover, we also performed RT-qPCR analysis to verify the expression levels of 13 target genes and the cleavage site of 5 target genes by known or novel miRNAs were validated experimentally by 5′ RACE. Additionally, a miRNA-mediated gene regulatory network for H2O2 stress response was constructed. Our study identifies a set of H2O2-responsive miRNAs and their target genes and reveals the mechanism of oxidative stress response and defense at the post-transcriptional regulatory level.

  18. Phylogeny in defining model plants for lignocellulosic ethanol production: a comparative study of Brachypodium distachyon, wheat, maize, and Miscanthus x giganteus leaf and stem biomass.

    Science.gov (United States)

    Meineke, Till; Manisseri, Chithra; Voigt, Christian A

    2014-01-01

    The production of ethanol from pretreated plant biomass during fermentation is a strategy to mitigate climate change by substituting fossil fuels. However, biomass conversion is mainly limited by the recalcitrant nature of the plant cell wall. To overcome recalcitrance, the optimization of the plant cell wall for subsequent processing is a promising approach. Based on their phylogenetic proximity to existing and emerging energy crops, model plants have been proposed to study bioenergy-related cell wall biochemistry. One example is Brachypodium distachyon, which has been considered as a general model plant for cell wall analysis in grasses. To test whether relative phylogenetic proximity would be sufficient to qualify as a model plant not only for cell wall composition but also for the complete process leading to bioethanol production, we compared the processing of leaf and stem biomass from the C3 grasses B. distachyon and Triticum aestivum (wheat) with the C4 grasses Zea mays (maize) and Miscanthus x giganteus, a perennial energy crop. Lambda scanning with a confocal laser-scanning microscope allowed a rapid qualitative analysis of biomass saccharification. A maximum of 108-117 mg ethanol·g(-1) dry biomass was yielded from thermo-chemically and enzymatically pretreated stem biomass of the tested plant species. Principal component analysis revealed that a relatively strong correlation between similarities in lignocellulosic ethanol production and phylogenetic relation was only given for stem and leaf biomass of the two tested C4 grasses. Our results suggest that suitability of B. distachyon as a model plant for biomass conversion of energy crops has to be specifically tested based on applied processing parameters and biomass tissue type.

  19. Arabidopsis and Brachypodium distachyon transgenic plants expressing Aspergillus nidulans acetylesterases have decreased degree of polysaccharide acetylation and increased resistance to pathogens.

    Science.gov (United States)

    Pogorelko, Gennady; Lionetti, Vincenzo; Fursova, Oksana; Sundaram, Raman M; Qi, Mingsheng; Whitham, Steven A; Bogdanove, Adam J; Bellincampi, Daniela; Zabotina, Olga A

    2013-05-01

    The plant cell wall has many significant structural and physiological roles, but the contributions of the various components to these roles remain unclear. Modification of cell wall properties can affect key agronomic traits such as disease resistance and plant growth. The plant cell wall is composed of diverse polysaccharides often decorated with methyl, acetyl, and feruloyl groups linked to the sugar subunits. In this study, we examined the effect of perturbing cell wall acetylation by making transgenic Arabidopsis (Arabidopsis thaliana) and Brachypodium (Brachypodium distachyon) plants expressing hemicellulose- and pectin-specific fungal acetylesterases. All transgenic plants carried highly expressed active Aspergillus nidulans acetylesterases localized to the apoplast and had significant reduction of cell wall acetylation compared with wild-type plants. Partial deacetylation of polysaccharides caused compensatory up-regulation of three known acetyltransferases and increased polysaccharide accessibility to glycosyl hydrolases. Transgenic plants showed increased resistance to the fungal pathogens Botrytis cinerea and Bipolaris sorokiniana but not to the bacterial pathogens Pseudomonas syringae and Xanthomonas oryzae. These results demonstrate a role, in both monocot and dicot plants, of hemicellulose and pectin acetylation in plant defense against fungal pathogens.

  20. Down-regulation of BdBRI1, a putative brassinosteroid receptor gene produces a dwarf phenotype with enhanced drought tolerance in Brachypodium distachyon.

    Science.gov (United States)

    Feng, Ying; Yin, Yanhai; Fei, Shuizhang

    2015-05-01

    Brassinosteroids (BRs) play important roles in plant growth, development and responses to a range of environmental cues. Although the mechanism of how BRs regulate growth and development is well-understood in Arabidopsis, the effect of BRs on stress tolerance, particularly drought tolerance remains unknown. We isolated a BRI1 (BRASSINOSTEROID INSENSITIVE 1) homologous gene, BdBRI1 from Brachypodium distachyon, a model for temperate grasses and cereals, created and characterized RNA interference (RNAi) knockdown mutants for BdBRI1 in Brachypodium. The loss-of-function BdBRI1-RNAi mutants exhibited reduced plant height, shortened internodes, narrow and short leaf, and reduced expression of BR signaling genes, BdBES1, BdBZR1, BdBLE2, and enhanced expression of BR biosynthesis genes BdD2, BdCPD and BdDWF4. More importantly, BdBRI1 RNAi mutants exhibited enhanced drought tolerance, accompanied by highly elevated expression of drought-responsive genes, BdP5CS, BdCOR47/BdRD17, together with BdERD1 and BdRD26, two putative targets of the transcription factors BES1 and BZR1 that are key components of the BR signaling pathway. Our results suggest that BR signaling and biosynthesis are largely conserved among Arabidopsis, rice and Brachypodium, and that BR signaling plays an important role in drought tolerance by directly regulating expression of key drought-responsive genes. The effect of BR biosynthesis or crosstalks between BR and other hormones or components of stress signaling pathways on drought tolerance is discussed.

  1. Mannans and endo-β-mannanases (MAN) in Brachypodium distachyon: expression profiling and possible role of the BdMAN genes during coleorhiza-limited seed germination.

    Science.gov (United States)

    González-Calle, Virginia; Barrero-Sicilia, Cristina; Carbonero, Pilar; Iglesias-Fernández, Raquel

    2015-07-01

    Immunolocalization of mannans in the seeds of Brachypodium distachyon reveals the presence of these polysaccharides in the root embryo and in the coleorhiza in the early stages of germination (12h), decreasing thereafter to the point of being hardly detected at 27h. Concurrently, the activity of endo-β-mannanases (MANs; EC 3.2.1.78) that catalyse the hydrolysis of β-1,4 bonds in mannan polymers, increases as germination progresses. The MAN gene family is represented by six members in the Brachypodium genome, and their expression has been explored in different organs and especially in germinating seeds. Transcripts of BdMAN2, BdMAN4 and BdMAN6 accumulate in embryos, with a maximum at 24-30h, and are detected in the coleorhiza and in the root by in situ hybridization analyses, before root protrusion (germination sensu stricto). BdMAN4 is not only present in the embryo root and coleorhiza, but is abundant in the de-embryonated (endosperm) imbibed seeds, while BdMAN2 and BdMAN6 are faintly expressed in endosperm during post-germination (36-42h). BdMAN4 and BdMAN6 transcripts are detected in the aleurone layer. These data indicate that BdMAN2, BdMAN4 and BdMAN6 are important for germination sensu stricto and that BdMAN4 and BdMAN6 may also influence reserve mobilization. Whether the coleorhiza in monocots and the micropylar endosperm in eudicots have similar functions, is discussed.

  2. A Member of the 14-3-3 Gene Family in Brachypodium distachyon, BdGF14d, Confers Salt Tolerance in Transgenic Tobacco Plants

    Science.gov (United States)

    He, Yuan; Zhang, Yang; Chen, Lihong; Wu, Chunlai; Luo, Qingchen; Zhang, Fan; Wei, Qiuhui; Li, Kexiu; Chang, Junli; Yang, Guangxiao; He, Guangyuan

    2017-01-01

    Plant 14-3-3 proteins are involved in diverse biological processes, but for the model monocotyledonous species, Brachypodium distachyon, their roles in abiotic stress tolerance are not well understood. In this study, a total of eight Bd14-3-3 genes were identified from B. distachyon and these were designated respectively as BdGF14a–BdGF14g. The qRT-PCR analyses of 3-month-old plants of B. distachyon showed that these genes were all expressed in the stems, leaves, and spikelets. By contrast, most of the plants had relatively lower transcriptional levels in their roots, except for the BdGF14g gene. The different expression profiles of the Bd14-3-3s under various stress treatments, and the diverse interaction patterns between Bd14-3-3s and BdAREB/ABFs, suggested that these gene products probably had a range of functions in the stress responses. The NaCl-induced Bd14-3-3 gene, BdGF14d, was selected for overexpression in tobacco. BdGF14d was found to be localized throughout the cell and it conferred enhanced tolerance to salt in the transgenic plants. Lowered contents of malondialdehyde, H2O2, and Na+, and lower relative electronic conductance (Rec%), yet greater activities of catalase and peroxidase, were observed in the overexpressing plants. Higher photosynthetic rate, transpiration rate, stomatal conductance, and water use efficiency were measured in the transgenic lines. Following abscisic acid (ABA) or NaCl treatment, stomatal aperture in leaves of the BdGF14d-overexpression plants was significantly lower than in leaves of the wild type (WT) controls. The stress-related marker genes involved in the ABA signaling pathway, the reactive oxygen species (ROS)-scavenging system, and the ion transporters were all up-regulated in the BdGF14d-overexpressing plants as compared with WT. Taken together, these results demonstrate that the Bd14-3-3 genes play important roles in abiotic stress tolerance. The ABA signaling pathway, the ROS-scavenging system, and ion

  3. Heat Stress Regulates the Expression of Genes at Transcriptional and Post-Transcriptional Levels, Revealed by RNA-seq in Brachypodium distachyon

    Science.gov (United States)

    Chen, Shoukun; Li, Haifeng

    2017-01-01

    Heat stress greatly affects plant growth/development and influences the output of crops. With the increased occurrence of extreme high temperature, the negative influence on cereal products from heat stress becomes severer and severer. It is urgent to reveal the molecular mechanism in response to heat stress in plants. In this research, we used RNA-seq technology to identify differentially expressed genes (DEGs) in leaves of seedlings, leaves and inflorescences at heading stage of Brachypodium distachyon, one model plant of grasses. Results showed many genes in responding to heat stress. Of them, the expression level of 656 DEGs were altered in three groups of samples treated with high temperature. Gene ontology (GO) analysis showed that the highly enriched DEGs were responsible for heat stress and protein folding. According to KEGG pathway analysis, the DEGs were related mainly to photosynthesis-antenna proteins, the endoplasmic reticulum, and the spliceosome. Additionally, the expression level of 454 transcription factors belonging to 49 gene families was altered, as well as 1,973 splicing events occurred after treatment with high temperature. This research lays a foundation for characterizing the molecular mechanism of heat stress response and identifying key genes for those responses in plants. These findings also clearly show that heat stress regulates the expression of genes not only at transcriptional level, but also at post-transcriptional level. PMID:28119730

  4. Pushing the boundaries of resistance: insights from Brachypodium-rust interactions

    Directory of Open Access Journals (Sweden)

    Melania eFigueroa

    2015-07-01

    Full Text Available The implications of global population growth urge transformation of current food and bioenergy production systems to sustainability. Members of the family Poaceae are of particular importance both in food security and for their applications as biofuel substrates. For centuries, rust fungi have threatened the production of valuable crops such as wheat, barley, oat and other small grains; similarly, biofuel crops can also be susceptible to these pathogens. Emerging rust pathogenic races with increased virulence and recurrent rust epidemics around the world point out the vulnerability of monocultures. Basic research in plant immunity, especially in model plants, can make contributions to understanding plant resistance mechanisms and improve disease management strategies. The development of the grass Brachypodium distachyon as a genetically tractable model for monocots, especially temperate cereals and grasses, offers the possibility to overcome the experimental challenges presented by the genetic and genomic complexities of economically valuable crop plants. The numerous resources and tools available in Brachypodium have opened new doors to investigate the underlying molecular and genetic bases of plant-microbe interactions in grasses and evidence demonstrating the applicability and advantages of working with B. distachyon is increasing. Importantly, several interactions between B. distachyon and devastating plant pathogens, such rust fungi, have been examined in the context of non-host resistance. Here, we discuss the use of B. distachyon in these various pathosystems. Exploiting B. distachyon to understand the mechanisms underpinning disease resistance to non-adapted rust fungi may provide effective and durable approaches to fend off these pathogens. The close phylogenetic relationship among Brachypodium spp. and grasses with industrial and agronomic value support harnessing this model plant to improve cropping systems and encourage its use in

  5. Variation in Adult Plant Phenotypes and Partitioning among Seed and Stem-Borne Roots across Brachypodium distachyon Accessions to Exploit in Breeding Cereals for Well-Watered and Drought Environments.

    Science.gov (United States)

    Chochois, Vincent; Vogel, John P; Rebetzke, Gregory J; Watt, Michelle

    2015-07-01

    Seedling roots enable plant establishment. Their small phenotypes are measured routinely. Adult root systems are relevant to yield and efficiency, but phenotyping is challenging. Root length exceeds the volume of most pots. Field studies measure partial adult root systems through coring or use seedling roots as adult surrogates. Here, we phenotyped 79 diverse lines of the small grass model Brachypodium distachyon to adults in 50-cm-long tubes of soil with irrigation; a subset of 16 lines was droughted. Variation was large (total biomass, ×8; total root length [TRL], ×10; and root mass ratio, ×6), repeatable, and attributable to genetic factors (heritabilities ranged from approximately 50% for root growth to 82% for partitioning phenotypes). Lines were dissected into seed-borne tissues (stem and primary seminal axile roots) and stem-borne tissues (tillers and coleoptile and leaf node axile roots) plus branch roots. All lines developed one seminal root that varied, with branch roots, from 31% to 90% of TRL in the well-watered condition. With drought, 100% of TRL was seminal, regardless of line because nodal roots were almost always inhibited in drying topsoil. Irrigation stimulated nodal roots depending on genotype. Shoot size and tillers correlated positively with roots with irrigation, but partitioning depended on genotype and was plastic with drought. Adult root systems of B. distachyon have genetic variation to exploit to increase cereal yields through genes associated with partitioning among roots and their responsiveness to irrigation. Whole-plant phenotypes could enhance gain for droughted environments because root and shoot traits are coselected.

  6. Update on the genomics and basic biology of Brachypodium

    DEFF Research Database (Denmark)

    Catalan, Pilar; Chalhoub, Boulos; Chochois, Vincent

    2014-01-01

    The scientific presentations at the First International Brachypodium Conference (abstracts available at http://www.brachy2013.unimore.it) are evidence of the wide-spread adoption of Brachypodium distachyon as a model system. Furthermore, the wide range of topics presented (genome evolution, roots...

  7. Genome-wide Identification and Analysis of WRKY Gene Family Members from Brachypodium distachyon%二穗短柄草WRKY基因家族成员的鉴定和分析

    Institute of Scientific and Technical Information of China (English)

    蒋明; 尹龙飞; 张志仙; 余沁欣; 罗礼礼

    2012-01-01

    WRKY转录因子以基因家族形式存在,在植物生长、发育和逆境反应中起着重要作用。二穗短柄草是大麦、小麦和禾本科牧草的模式植物,为了给基因表达和功能鉴定奠定基础,本研究利用生物信息学方法鉴定和分析其WRKY转录因子。结果表明,二穗短柄草有76个WRKY基因,它们具有0~6个内含子,编码区全长396~2 847 bp,基因分布在5条染色体上;进化分析结果表明,二穗短柄草WRKY在系统发生树上聚为3组,分属于I、II和III类转录因子;核心序列除WRKYGQK外,还有WKKYGQK、WRKYGKK、WRKY-GEK、WRKYGQT和WKKYGPK等多种变异类型;锌指模体也存在多种变异,它们是C-X4-C-X21-H-X1-H、C-X3-C-X22-H-X1-H、C-X7-C-X28-H-X1-C、C-X7-C-X24-H-X1-C、C-X7-C-X26-H-X1-C、C-X6-C-X24-H-X1-C、C-X7-C-X33-H-X1-C、C-X6-C-X32-H-X1-C和C-X7-C-X32-H-X1-C。%WRKY transcription factors belong to a gene family,and play important roles in plant growth,development as well as stress responses.Brachypodium distachyonacts as a model plant for Hordeum vulgare,Triticum aestivum and Gramineae grasses.To provide a basis for gene expression and functional characterization of genes,bioinformatic techniques were performed to identify WRKY transcription factors.Results indicated that there were 76 WRKY genes in B.distachyon with 0~6 introns.The coding sequences were 396~2 847 bp in length,and the genes distributed in 5 different chromosomes.Phylogenetic analysis revealed that the WRKYs were clustered into 3 groups and they belonged to I,II and III transcription factors,respectively.Besides WRKYGQK,several core sequence variants as WKKYGQK,WRKYGKK,WRKYGEK,WRKYGQT and WKKYGPK were identified.Mutations in zinc finger motifs were also observed,the variants included C-X4-C-X21-H-X1-H,C-X3-C-X22-H-X1-H,C-X7-C-X28-H-X1-C,C-X7-C-X24-H-X1-C,C-X7-C-X26-H-X1-C,C-X6-C-X24-H-X1-C,C-X7-C-X33-H-X1-C,C-X6-C-X32-H-X1-C and C-X7-C-X32-H-X1-C.

  8. Brachypodium distachyon

    DEFF Research Database (Denmark)

    Tanackovic, Vanja

    Starch is one of the most abundant polysaccharides on the Earth, the principal energy storage of most plant species and of crucial significance for humans as a major nutrient in human diet. The majority of produced starch comes from cereals, domesticated grasses, characterized by specific en...

  9. Genome-Wide Analysis of miRNA targets in Brachypodium and Biomass Energy Crops

    Energy Technology Data Exchange (ETDEWEB)

    Green, Pamela J. [Univ. of Delaware, Newark, DE (United States)

    2015-08-11

    MicroRNAs (miRNAs) contribute to the control of numerous biological processes through the regulation of specific target mRNAs. Although the identities of these targets are essential to elucidate miRNA function, the targets are much more difficult to identify than the small RNAs themselves. Before this work, we pioneered the genome-wide identification of the targets of Arabidopsis miRNAs using an approach called PARE (German et al., Nature Biotech. 2008; Nature Protocols, 2009). Under this project, we applied PARE to Brachypodium distachyon (Brachypodium), a model plant in the Poaceae family, which includes the major food grain and bioenergy crops. Through in-depth global analysis and examination of specific examples, this research greatly expanded our knowledge of miRNAs and target RNAs of Brachypodium. New regulation in response to environmental stress or tissue type was found, and many new miRNAs were discovered. More than 260 targets of new and known miRNAs with PARE sequences at the precise sites of miRNA-guided cleavage were identified and characterized. Combining PARE data with the small RNA data also identified the miRNAs responsible for initiating approximately 500 phased loci, including one of the novel miRNAs. PARE analysis also revealed that differentially expressed miRNAs in the same family guide specific target RNA cleavage in a correspondingly tissue-preferential manner. The project included generation of small RNA and PARE resources for bioenergy crops, to facilitate ongoing discovery of conserved miRNA-target RNA regulation. By associating specific miRNA-target RNA pairs with known physiological functions, the research provides insights about gene regulation in different tissues and in response to environmental stress. This, and release of new PARE and small RNA data sets should contribute basic knowledge to enhance breeding and may suggest new strategies for improvement of biomass energy crops.

  10. Insight into the karyotype evolution of brachypodium species using comparative chromosome barcoding.

    Directory of Open Access Journals (Sweden)

    Dominika Idziak

    Full Text Available Paleogenomic studies based on bioinformatic analyses of DNA sequences have enabled unprecedented insight into the evolution of grass genomes. They have revealed that nested chromosome fusions played an important role in the divergence of modern grasses. Nowadays, studies on karyotype evolution based on the sequence analysis can also be effectively complemented by the fine-scale cytomolecular approach. In this work, we studied the karyotype evolution of small genome grasses using BAC-FISH based comparative chromosome barcoding in four Brachypodium species: diploid B. distachyon (2n = 10 and B. sylvaticum (2n = 18, diploid (2n = 18 and allopolyploid (2n = 28 B. pinnatum as well as B. phoenicoides (2n = 28. Using BAC clones derived from the B. distachyon genomic libraries for the chromosomes Bd2 and Bd3, we identified the descending dysploidy events that were common for diploids with x = 9 and B. distachyon as well as two nested chromosome fusions that were specific only for B. distachyon. We suggest that dysploidy events that are shared by different lineages of the genus had already appeared in their common ancestor. We also show that additional structural rearrangements, such as translocations and duplications, contributed to increasing genome diversification in the species analysed. No chromosomes structured exactly like Bd2 and Bd3 were found in B. pinnatum (2n = 28 and B. phoenicoides. The structure of Bd2 and Bd3 homeologues belonging to the two genomes in the allopolyploids resembled the structure of their counterparts in the 2n = 18 diploids. These findings reinforce the hypothesis which excludes B. distachyon as a potential parent for Eurasian perennial Brachypodium allopolyploids. Our cytomolecular data elucidate some mechanisms of the descending dysploidy in monocots and enable reconstructions of the evolutionary events which shaped the extant karyotypes in both the genus Brachypodium and in grasses as a whole.

  11. Deep sequencing of Brachypodium small RNAs at the global genome level identifies microRNAs involved in cold stress response

    Directory of Open Access Journals (Sweden)

    Chong Kang

    2009-09-01

    Full Text Available Abstract Background MicroRNAs (miRNAs are endogenous small RNAs having large-scale regulatory effects on plant development and stress responses. Extensive studies of miRNAs have only been performed in a few model plants. Although miRNAs are proved to be involved in plant cold stress responses, little is known for winter-habit monocots. Brachypodium distachyon, with close evolutionary relationship to cool-season cereals, has recently emerged as a novel model plant. There are few reports of Brachypodium miRNAs. Results High-throughput sequencing and whole-genome-wide data mining led to the identification of 27 conserved miRNAs, as well as 129 predicted miRNAs in Brachypodium. For multiple-member conserved miRNA families, their sizes in Brachypodium were much smaller than those in rice and Populus. The genome organization of miR395 family in Brachypodium was quite different from that in rice. The expression of 3 conserved miRNAs and 25 predicted miRNAs showed significant changes in response to cold stress. Among these miRNAs, some were cold-induced and some were cold-suppressed, but all the conserved miRNAs were up-regulated under cold stress condition. Conclusion Our results suggest that Brachypodium miRNAs are composed of a set of conserved miRNAs and a large proportion of non-conserved miRNAs with low expression levels. Both kinds of miRNAs were involved in cold stress response, but all the conserved miRNAs were up-regulated, implying an important role for cold-induced miRNAs. The different size and genome organization of miRNA families in Brachypodium and rice suggest that the frequency of duplication events or the selection pressure on duplicated miRNAs are different between these two closely related plant species.

  12. MORE SPIKELETS1 is required for spikelet fate in the inflorescence of Brachypodium.

    Science.gov (United States)

    Derbyshire, Paul; Byrne, Mary E

    2013-03-01

    Grasses produce florets on a structure called a spikelet, and variation in the number and arrangement of both branches and spikelets contributes to the great diversity of grass inflorescence architecture. In Brachypodium (Brachypodium distachyon), the inflorescence is an unbranched spike with a terminal spikelet and a limited number of lateral spikelets. Spikelets are indeterminate and give rise to a variable number of florets. Here, we provide a detailed description of the stages of inflorescence development in Brachypodium. To gain insight into the genetic regulation of Brachypodium inflorescence development, we generated fast neutron mutant populations and screened for phenotypic mutants. Among the mutants identified, the more spikelets1 (mos1) mutant had an increased number of axillary meristems produced from inflorescence meristem compared with the wild type. These axillary meristems developed as branches with production of higher order spikelets. Using a candidate gene approach, mos1 was found to have a genomic rearrangement disrupting the expression of an ethylene response factor class of APETALA2 transcription factor related to the spikelet meristem identity genes branched silkless1 (bd1) in maize (Zea mays) and FRIZZY PANICLE (FZP) in rice (Oryza sativa). We propose MOS1 likely corresponds to the Brachypodium bd1 and FZP ortholog and that the function of this gene in determining spikelet meristem fate is conserved with distantly related grass species. However, MOS1 also appears to be involved in the timing of initiation of the terminal spikelet. As such, MOS1 may regulate the transition to terminal spikelet development in other closely related and agriculturally important species, particularly wheat (Triticum aestivum).

  13. Brachypodium as an experimental system for the study of stem parenchyma biology in grasses.

    Science.gov (United States)

    Jensen, Jacob Krüger; Wilkerson, Curtis Gene

    2017-01-01

    Stem parenchyma is a major cell type that serves key metabolic functions for the plant especially in large grasses, such as sugarcane and sweet sorghum, where it serves to store sucrose or other products of photosynthesis. It is therefore desirable to understand the metabolism of this cell type as well as the mechanisms by which it provides its function for the rest of the plant. Ultimately, this information can be used to selectively manipulate this cell type in a controlled manner to achieve crop improvement. In this study, we show that Brachypodium distachyon is a useful model system for stem pith parenchyma biology. Brachypodium can be grown under condition where it resembles the growth patterns of important crops in that it produces large amounts of stem material with the lower leaves senescing and with significant stores of photosynthate located in the stem parenchyma cell types. We further characterize stem plastid morphology as a function of tissue types, as this organelle is central for a number of metabolic pathways, and quantify gene expression for the four main classes of starch biosynthetic genes. Notably, we find several of these genes differentially regulated between stem and leaf. These studies show, consistent with other grasses, that the stem functions as a specialized storage compartment in Brachypodium.

  14. Accelerated rates of protein evolution in barley grain and pistil biased genes might be legacy of domestication.

    Science.gov (United States)

    Shi, Tao; Dimitrov, Ivan; Zhang, Yinling; Tax, Frans E; Yi, Jing; Gou, Xiaoping; Li, Jia

    2015-10-01

    Traits related to grain and reproductive organs in grass crops have been under continuous directional selection during domestication. Barley is one of the oldest domesticated crops in human history. Thus genes associated with the grain and reproductive organs in barley may show evidence of dramatic evolutionary change. To understand how artificial selection contributes to protein evolution of biased genes in different barley organs, we used Digital Gene Expression analysis of six barley organs (grain, pistil, anther, leaf, stem and root) to identify genes with biased expression in specific organs. Pairwise comparisons of orthologs between barley and Brachypodium distachyon, as well as between highland and lowland barley cultivars mutually indicated that grain and pistil biased genes show relatively higher protein evolutionary rates compared with the median of all orthologs and other organ biased genes. Lineage-specific protein evolutionary rates estimation showed similar patterns with elevated protein evolution in barley grain and pistil biased genes, yet protein sequences generally evolve much faster in the lowland barley cultivar. Further functional annotations revealed that some of these grain and pistil biased genes with rapid protein evolution are related to nutrient biosynthesis and cell cycle/division. Our analyses provide insights into how domestication differentially shaped the evolution of genes specific to different organs of a crop species, and implications for future functional studies of domestication genes.

  15. Range of cell-wall alterations enhance saccharification in Brachypodium distachyon mutants

    DEFF Research Database (Denmark)

    Marriott, Poppy E; Sibout, Richard; Lapierre, Catherine

    2014-01-01

    Lignocellulosic plant biomass is an attractive feedstock for the production of sustainable biofuels, but the commercialization of such products is hampered by the high costs of processing this material into fermentable sugars (saccharification). One approach to lowering these costs is to produce ...

  16. Molecular genetic investigations of root gravitropism and other complex growth behaviors using Arabidopsis and Brachypodium as models

    Science.gov (United States)

    Masson, Patrick; Barker, Richard; Miller, Nathan; Su, Shih-Hao; Su, Shih-Heng

    2016-07-01

    When growing on hard surfaces, Arabidopsis roots tend to grown downward, as dictated by positive gravitropism. At the same time, surface-derived stimuli promote a wavy pattern of growth that is superimposed to a rightward root-skewing trend. This behavior is believed to facilitate obstacle avoidance in soil. To better understand these complex behaviors, we have isolated and characterized mutations that affect them. Some of these mutations were shown to affect gravitropism whereas others did not. Within the latter group, most of the mutations affected mechanisms that control anisotropic cell expansion. We have also characterized mutations that affect early steps of gravity signal transduction within the gravity-sensing columella cells of the root cap. Upon reorientation within the gravity field, starch-filled plastids sediment to the bottom-side of these cells, triggering a pathway that leads to re-localization of auxin efflux facilitators to the bottom membrane. Lateral auxin transport toward the bottom flank ensues, leading to gravitropic curvature. Several of the mutations we characterized affect genes that encode proteins associated with the vesicle trafficking pathway needed for this cell polarization. Other mutations were shown to affect components of the plastid outer envelope protein import complex (TOC). Their functional analysis suggests an active role for plastids in gravity signal transduction, beyond a simple contribution as sedimenting gravity susceptors. Because most cultivated crops are monocots, not dicots like Arabidopsis, we have also initiated studies of root-growth behavior with Brachypodium distachyon. When responding to a gravistimulus, the roots of Brachypodium seedlings develop a strong downward curvature that proceeds until the tip reaches a ~50-degree curvature. At that time, an oscillatory tip movement occurs while the root continues its downward reorientation. These root-tip oscillations also occur if roots are allowed to simply grow

  17. Protein (Viridiplantae): 357118651 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 15368:1608 PREDICTED: uncharacterized protein LOC100826717 Brachypodium distachyon MGACVSRPSACVGKPNTPRSGDAARAGGARRRRRRGKGRRTAPSRAASM...ETIQEAEGSVSPSAAAASASGDCRTYSNPAFQVTGSLEEAWYDSFAISESDGEDDF

  18. Protein (Viridiplantae): 357159140 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 2 PREDICTED: thiosulfate sulfurtransferase, chloroplastic-like Brachypodium distachyon MATADNKEQAILPMVDADEARALLSSGHGYLDARMPEDFDKGHAPG...ARNIPYYVYVAPGQGREKNPHFEQEVAALYGKEDHLIVGCFTGTRSKLATSDLLKAGFKNVRNLQGGYRAFLQSASQQQPVNDQQPSAN ...

  19. Using the Model Perennial Grass Brachypodium sylvaticum to Engineer Resistance to Multiple Abiotic Stresses

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, Sean; Reguera, Maria; Sade, Nir; Cartwright, Amy; Tobias, Christian; Thilmony, Roger; Blumwald, Eduardo; Vogel, John

    2015-03-20

    We are using the perennial model grass Brachypodium sylvaticum to identify combinations of transgenes that enhance tolerance to multiple, simultaneous abiotic stresses. The most successful transgene combinations will ultimately be used to create improved switchgrass (Panicum virgatum L.) cultivars. To further develop B. sylvaticum as a perennial model grass, and facilitate our planned transcriptional profiling, we are sequencing and annotating the genome. We have generated ~40x genome coverage using PacBio sequencing of the largest possible size selected libraries (18, 22, 25 kb). Our initial assembly using only long-read sequence contained 320 Mb of sequence with an N50 contig length of 315 kb and an N95 contig length of 40 kb. This assembly consists of 2,430 contigs, the largest of which was 1.6 Mb. The estimated genome size based on c-values is 340 Mb indicating that about 20 Mb of presumably repetitive DNA remains yet unassembled. Significantly, this assembly is far superior to an assembly created from paired-end short-read sequence, ~100x genome coverage. The short-read-only assembly contained only 226 Mb of sequence in 19k contigs. To aid the assembly of the scaffolds into chromosome-scale assemblies we produced an F2 mapping population and have genotyped 480 individuals using a genotype by sequence approach. One of the reasons for using B. sylvaticum as a model system is to determine if the transgenes adversely affect perenniality and winter hardiness. Toward this goal, we examined the freezing tolerance of wild type B. sylvaticum lines to determine the optimal conditions for testing the freezing tolerance of the transgenics. A survey of seven accessions noted significant natural variation in freezing tolerance. Seedling or adult Ain-1 plants, the line used for transformation, survived an 8 hour challenge down to -6 oC and 50% survived a challenge down to -9 oC. Thus, we will be able to easily determine if the transgenes compromise freezing tolerance. In the

  20. Brachypodium sylvaticum, a model for perennial grasses: transformation and inbred line development.

    Directory of Open Access Journals (Sweden)

    Michael A Steinwand

    Full Text Available Perennial species offer significant advantages as crops including reduced soil erosion, lower energy inputs after the first year, deeper root systems that access more soil moisture, and decreased fertilizer inputs due to the remobilization of nutrients at the end of the growing season. These advantages are particularly relevant for emerging biomass crops and it is projected that perennial grasses will be among the most important dedicated biomass crops. The advantages offered by perennial crops could also prove favorable for incorporation into annual grain crops like wheat, rice, sorghum and barley, especially under the dryer and more variable climate conditions projected for many grain-producing regions. Thus, it would be useful to have a perennial model system to test biotechnological approaches to crop improvement and for fundamental research. The perennial grass Brachypodiumsylvaticum is a candidate for such a model because it is diploid, has a small genome, is self-fertile, has a modest stature, and short generation time. Its close relationship to the annual model Brachypodiumdistachyon will facilitate comparative studies and allow researchers to leverage the resources developed for B. distachyon. Here we report on the development of two keystone resources that are essential for a model plant: high-efficiency transformation and inbred lines. Using Agrobacterium tumefaciens-mediated transformation we achieved an average transformation efficiency of 67%. We also surveyed the genetic diversity of 19 accessions from the National Plant Germplasm System using SSR markers and created 15 inbred lines.

  1. Protein (Viridiplantae): 357168562 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available TED: LOW QUALITY PROTEIN: dihydroflavonol-4-reductase-like, partial Brachypodium distachyon KVGADHDTRITPMSSE...LIYVIKGGPNAISDMSWHIVDVHDVADALLLVYEKPELSGRYICAPNXISTKVVLELLKKTYPDYNYVMCKVGADHDTRITPISSKKLRNLGWKPRKLEETLLDSVEYCXETGILQDVEGRAYRLPNVFLFFHAIEE ...

  2. Protein (Viridiplantae): 357112535 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 368:1152 PREDICTED: putative calmodulin-like protein 6-like Brachypodium distachyon MCPGGRYAGLDIPAGAGAADLRPAFDVLDADHD...GRISREDLKSFYAKAGAHEPFDDDDIAAMIAAADADHDGFVQYDEFEGLLGRAAATGTAGGCRSAMEDAFRLMDRDGDGKVGFEDLKAYLGWAGMPVADDEIRAMIGMAGDVDGGVGLEAFARVLAVDLDGIL ...

  3. Dicty_cDB: SHB481 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 5_075 Brachypodium distachyon developing spike EST library Brachypodium distachyon cDNA clone 5484_C09_E18, ...257_H11_P21, mRNA sequence. 42 7.6 1 DV474787 |DV474787.1 5484_C09_E18ZE5_075 Brachypodium distachyon developing

  4. Characterization of Phosphate Transporters BdPT4 and BdPT8 in Mycorrhizal and Non-Mychorrhizal Brachypodium distachyon

    DEFF Research Database (Denmark)

    Clausen, Signe Sandbech

    was generated by Agrobacterium tumefaciens-mediated transformation. The transgenic lines were characterized for effects on growth and plant P uptake, and their subcellular localization was moreover determined by confocal microscopy. Quantitative expression analysis of 11 BdPTs in AM and non-mycorrhizal (NM...

  5. Effects of Environmental Conditions on the Fitness Penalty in Herbicide Resistant Brachypodium hybridum

    Science.gov (United States)

    Frenkel, Eyal; Matzrafi, Maor; Rubin, Baruch; Peleg, Zvi

    2017-01-01

    Herbicide-resistance mutations may impose a fitness penalty in herbicide-free environments. Moreover, the fitness penalty associated with herbicide resistance is not a stable parameter and can be influenced by ecological factors. Here, we used two Brachypodium hybridum accessions collected from the same planted forest, sensitive (S) and target-site resistance (TSR) to photosystem II (PSII) inhibitors, to study the effect of agro-ecological parameters on fitness penalty. Both accessions were collected in the same habitat, thus, we can assume that the genetic variance between them is relatively low. This allow us to focus on the effect of PSII TSR on plant fitness. S plants grains were significantly larger than those of the TSR plants and this was associated with a higher rate of germination. Under low radiation, the TSR plants showed a significant fitness penalty relative to S plants. S plants exhibiting dominance when both types of plants were grown together in a low-light environment. In contrast to previous documented studies, under high-light environment our TSR accession didn’t show any significant difference in fitness compared to the S accession. Nitrogen deficiency had significant effect on the R compared to the S accession and was demonstrated in significant yield reduction. TSR plants also expressed a high fitness penalty, relative to the S plants, when grown in competition with wheat plants. Two evolutionary scenarios can be suggested to explain the coexistence of both TSR and S plants in the same habitat. The application of PSII inhibitors may have created selective pressure toward TSR dominancy; termination of herbicide application gave an ecological advantage to S plants, creating changes in the composition of the seed bank. Alternatively, the high radiation intensities found in the Mediterranean-like climate may reduce the fitness penalty associated with TSR. Our results may suggest that by integrating non-herbicidal approaches into weed

  6. Protein (Viridiplantae): 357120636 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 8 15368:3518 PREDICTED: fatty acyl-CoA reductase 2-like Brachypodium distachyon MGSSPCVNLSRAAARRPAAGRGFAHRRS...NPDVGKIYVVIKAKDSEAALQRLRNEVVDTELFRCLQEIHGKDYHSFVAAKLVPVVGDVREANIGIAPELADEIAERVDIIVNSAANTTFDERYDVAMDINTVGPFRIMSFAHR

  7. Protein (Viridiplantae): 357123379 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available :497 PREDICTED: BTB/POZ and MATH domain-containing protein 2-like Brachypodium distachyon MEKDCKSITNVARWVKLLKIDGYCAAKTMGNEDC...PSPEKSVSCIFNRSWISRCLEMCSPFVNEDCSLPVCLKSTGELAASGYLRNDSFTVQCTITVLKEDVPAARIPVKEVSVSSPSLQHHLAELLHNKTGTDVTFLVSGKS

  8. Genome-wide distribution and organization of microsatellites in plants: an insight into marker development in Brachypodium.

    Science.gov (United States)

    Sonah, Humira; Deshmukh, Rupesh K; Sharma, Anshul; Singh, Vinay P; Gupta, Deepak K; Gacche, Raju N; Rana, Jai C; Singh, Nagendra K; Sharma, Tilak R

    2011-01-01

    Plant genomes are complex and contain large amounts of repetitive DNA including microsatellites that are distributed across entire genomes. Whole genome sequences of several monocot and dicot plants that are available in the public domain provide an opportunity to study the origin, distribution and evolution of microsatellites, and also facilitate the development of new molecular markers. In the present investigation, a genome-wide analysis of microsatellite distribution in monocots (Brachypodium, sorghum and rice) and dicots (Arabidopsis, Medicago and Populus) was performed. A total of 797,863 simple sequence repeats (SSRs) were identified in the whole genome sequences of six plant species. Characterization of these SSRs revealed that mono-nucleotide repeats were the most abundant repeats, and that the frequency of repeats decreased with increase in motif length both in monocots and dicots. However, the frequency of SSRs was higher in dicots than in monocots both for nuclear and chloroplast genomes. Interestingly, GC-rich repeats were the dominant repeats only in monocots, with the majority of them being present in the coding region. These coding GC-rich repeats were found to be involved in different biological processes, predominantly binding activities. In addition, a set of 22,879 SSR markers that were validated by e-PCR were developed and mapped on different chromosomes in Brachypodium for the first time, with a frequency of 101 SSR markers per Mb. Experimental validation of 55 markers showed successful amplification of 80% SSR markers in 16 Brachypodium accessions. An online database 'BraMi' (Brachypodium microsatellite markers) of these genome-wide SSR markers was developed and made available in the public domain. The observed differential patterns of SSR marker distribution would be useful for studying microsatellite evolution in a monocot-dicot system. SSR markers developed in this study would be helpful for genomic studies in Brachypodium and related

  9. Testing assumptions of the enemy release hypothesis: generalist versus specialist enemies of the grass Brachypodium sylvaticum.

    Science.gov (United States)

    Halbritter, Aud H; Carroll, George C; Güsewell, Sabine; Roy, Bitty A

    2012-01-01

    The enemy release hypothesis (ERH) suggests greater success of species in an invaded range due to release from natural enemies. The ERH assumes there will be more specialist enemies in the native range and that generalists will have an equal effect in both ranges. We tested these assumptions with the grass Brachypodium sylvaticum in the native range (Switzerland) and invaded range (Oregon, USA). We assessed all the kinds of damage present (caused by fungi, insects, mollusk and deer) on both leaves and seeds at 10 sites in each range and correlated damage with host fitness. Only two of the 20 fungi found on leaves were specialist pathogens, and these were more frequent in the native range. Conversely there was more insect herbivory on leaves in the invaded range. All fungi and insects found on seeds were generalists. More species of fungi were found on seeds in the native range, and a higher proportion of them were pathogenic than in the invaded range. There were more kinds of enemies in the native range, where the plants had lower fitness, in accordance with the ERH. However, contrary to assumptions of the ERH, generalists appear to be equally or more important than specialists in reducing host fitness.

  10. Population regulation by enemies of the grass Brachypodium sylvaticum: demography in native and invaded ranges.

    Science.gov (United States)

    Roy, Bitty A; Coulson, Tim; Blaser, Wilma; Policha, Tobias; Stewart, Julie L; Blaisdell, G Kai; Güsewell, Sabine

    2011-03-01

    The enemy-release hypothesis (ERH) states that species become more successful in their introduced range than in their native range because they leave behind natural enemies in their native range and are thus "released" from enemy pressures in their introduced range. The ERH is popularly cited to explain the invasive properties of many species and is the underpinning of biological control. We tested the prediction that plant populations are more strongly regulated by natural enemies (herbivores and pathogens) in their native range than in their introduced range with enemy-removal experiments using pesticides. These experiments were replicated at multiple sites in both the native and invaded ranges of the grass Brachypodium sylvaticum. In support of the ERH, enemies consistently regulated populations in the native range. There were more tillers and more seeds produced in treated vs. untreated plots in the native range, and few seedlings survived in the native range. Contrary to the ERH, total measured leaf damage was similar in both ranges, though the enemies that caused it differed. There was more damage by generalist mollusks and pathogens in the native range, and more damage by generalist insect herbivores in the invaded range. Demographic analysis showed that population growth rates were lower in the native range than in the invaded range, and that sexually produced seedlings constituted a smaller fraction of the total in the native range. Our removal experiment showed that enemies regulate plant populations in their native range and suggest that generalist enemies, not just specialists, are important for population regulation.

  11. Contracts for Grain Biosecurity and Grain Quality

    OpenAIRE

    Abougamos, Hoda; White, Benedict; Sadler,Rohan

    2012-01-01

    The export of grain from Western Australia depends upon a grain supply network that takes grain from farm to port through Cooperative Bulk Handling receival and storage sites. The ability of the network to deliver pest free grain to the port and onto ship depends upon the quality of grain delivered by farmers and the efficacy of phosphine based fumigation in controlling stored grain pests. Phosphine fumigation is critical to the grain supply network because it is the cheapest effective fumiga...

  12. Grain Spectroscopy

    Science.gov (United States)

    Allamandola, L. J.

    1992-01-01

    Our fundamental knowledge of interstellar grain composition has grown substantially during the past two decades thanks to significant advances in two areas: astronomical infrared spectroscopy and laboratory astrophysics. The opening of the mid-infrared, the spectral range from 4000-400 cm(sup -1) (2.5-25 microns), to spectroscopic study has been critical to this progress because spectroscopy in this region reveals more about a materials molecular composition and structure than any other physical property. Infrared spectra which are diagnostic of interstellar grain composition fall into two categories: absorption spectra of the dense and diffuse interstellar media, and emission spectra from UV-Vis rich dusty regions. The former will be presented in some detail, with the latter only very briefly mentioned. This paper summarized what we have learned from these spectra and presents 'doorway' references into the literature. Detailed reviews of many aspects of interstellar dust are given.

  13. Dormancy and Germination of Brochypodium distachyon Caryopses Derived from Israel%以色列二穗短柄草(Brochypodium distachyon)种子的休眠与萌发特性

    Institute of Scientific and Technical Information of China (English)

    严俊; 程剑平; 王莹; GUTTERMAN Yitzchak; NEVO Eviatar

    2008-01-01

    对以色列3个群体的二穗短柄草(Brochypodium distachyon)种子的休眠与萌发进行了研究.结果表明:以色列二穗短柄草种子都具有休眠的习性,且不属于外源休眠(种壳休眠)类型;储藏温度和时间等因素对不同群体的二穗短柄草种子的休眠和萌发有着极显著的影响,高温(40℃)储藏可以加快种子后熟,打破种子的休眠;3个群体的二穗短柄草种子休眠深度不同,依次是:Sede Boqer>Yatk>Mt.carmel;且休眠深度与群体生长地年平均降雨量呈负相关关系.二穗短柄草的这些休眠和萌发特性可能是其长期与环境相互作用,在自然选择压力下进化形成的存活机制.

  14. Microbiota of kefir grains

    Directory of Open Access Journals (Sweden)

    Tomislav Pogačić

    2013-03-01

    Full Text Available Kefir grains represent the unique microbial community consisting of bacteria, yeasts, and sometimes filamentous moulds creating complex symbiotic community. The complexity of their physical and microbial structures is the reason that the kefir grains are still not unequivocally elucidated. Microbiota of kefir grains has been studied by many microbiological and molecular approaches. The development of metagenomics, based on the identification without cultivation, is opening new possibilities for identification of previously nonisolated and non-identified microbial species from the kefir grains. Considering recent studies, there are over 50 microbial species associated with kefir grains. The aim of this review is to summarise the microbiota composition of kefir grains. Moreover, because of technological and microbiological significance of the kefir grains, the paper provides an insight into the microbiological and molecular methods applied to study microbial biodiversity of kefir grains.

  15. Against the Grain

    DEFF Research Database (Denmark)

    Pedersen, Peter Ole

    2016-01-01

    Katalog-tekst til udstillingen Against the Grain om atomar-fotografi og det antropocæne. Kurateret af Peter Ole Pedersen på Galleri Image, august-oktober 2016.......Katalog-tekst til udstillingen Against the Grain om atomar-fotografi og det antropocæne. Kurateret af Peter Ole Pedersen på Galleri Image, august-oktober 2016....

  16. GrainSpotter

    DEFF Research Database (Denmark)

    Schmidt, Søren

    2014-01-01

    A new approach for indexing multigrain diffraction data is presented. It is based on the use of a monochromatic beam simultaneously illuminating all grains. By operating in sub-volumes of Rodrigues space, a powerful vertex-finding algorithm can be applied, with a running time that is compatible...... with online analysis. The resulting program, GrainSpotter, is sufficiently fast to enable online analysis during synchrotron sessions. The program applies outlier rejection schemes, leading to more robust and accurate data. By simulations it is shown that several thousand grains can be retrieved. A new method...... to derive partial symmetries, called pseudo-twins, is introduced. Uniquely, GrainSpotter includes an analysis of pseudo-twins, which is shown to be critical to avoid erroneous grains resulting from the indexing....

  17. Physics of Grain Alignment

    CERN Document Server

    Lazarian, A

    2000-01-01

    Aligned grains provide one of the easiest ways to study magnetic fields in diffuse gas and molecular clouds. How reliable our conclusions about the inferred magnetic field depends critically on our understanding of the physics of grain alignment. Although grain alignment is a problem of half a century standing recent progress achieved in the field makes us believe that we are approaching the solution of this mystery. I review basic physical processes involved in grain alignment and show why mechanisms that were favored for decades do not look so promising right now. I also discuss why the radiative torque mechanism ignored for more than 20 years looks right now the most powerful means of grain alignment.

  18. Grain Boundary Complexions

    Science.gov (United States)

    2014-05-01

    theories of grain boundary adsorption were based on the McLean model, which assumes that segregation is constrained to a monolayer of atomic sites at the...New York: McGraw- Hill ; 1956. [58] de Boer JH. The dynamical character of adsorption . London: Oxford University Press; 1953. [59] McLean D. Grain...Overview No. 152 Grain boundary complexions Patrick R. Cantwell a, Ming Tang b,1, Shen J. Dillon c, Jian Luo d, Gregory S . Rohrer e, Martin P. Harmer

  19. Folding of Pollen Grains

    Science.gov (United States)

    Katifori, Eleni; Alben, Silas; Cerda, Enrique; Nelson, David; Dumais, Jacques

    2008-03-01

    At dehiscence, which occurs when the anther reaches maturity and opens, pollen grains dehydrate and their volume is reduced. The pollen wall deforms to accommodate the volume loss, and the deformation pathway depends on the initial turgid pollen grain geometry and the mechanical properties of the pollen wall. We demonstrate, using both experimental and theoretical approaches, that the design of the apertures (areas on the pollen wall where the stretching and the bending modulus are reduced) is critical for controlling the folding pattern, and ensures the pollen grain viability. An excellent fit to the experiments is obtained using a discretized version of the theory of thin elastic shells.

  20. Syntenic relationships between the U and M genomes of Aegilops, wheat and the model species Brachypodium and rice as revealed by COS markers.

    Science.gov (United States)

    Molnár, István; Šimková, Hana; Leverington-Waite, Michelle; Goram, Richard; Cseh, András; Vrána, Jan; Farkas, András; Doležel, Jaroslav; Molnár-Láng, Márta; Griffiths, Simon

    2013-01-01

    Diploid Aegilops umbellulata and Ae. comosa and their natural allotetraploid hybrids Ae. biuncialis and Ae. geniculata are important wild gene sources for wheat. With the aim of assisting in alien gene transfer, this study provides gene-based conserved orthologous set (COS) markers for the U and M genome chromosomes. Out of the 140 markers tested on a series of wheat-Aegilops chromosome introgression lines and flow-sorted subgenomic chromosome fractions, 100 were assigned to Aegilops chromosomes and six and seven duplications were identified in the U and M genomes, respectively. The marker-specific EST sequences were BLAST-ed to Brachypodium and rice genomic sequences to investigate macrosyntenic relationships between the U and M genomes of Aegilops, wheat and the model species. Five syntenic regions of Brachypodium identified genome rearrangements differentiating the U genome from the M genome and from the D genome of wheat. All of them seem to have evolved at the diploid level and to have been modified differentially in the polyploid species Ae. biuncialis and Ae. geniculata. A certain level of wheat-Aegilops homology was detected for group 1, 2, 3 and 5 chromosomes, while a clearly rearranged structure was showed for the group 4, 6 and 7 Aegilops chromosomes relative to wheat. The conserved orthologous set markers assigned to Aegilops chromosomes promise to accelerate gene introgression by facilitating the identification of alien chromatin. The syntenic relationships between the Aegilops species, wheat and model species will facilitate the targeted development of new markers specific for U and M genomic regions and will contribute to the understanding of molecular processes related to allopolyploidization.

  1. Syntenic relationships between the U and M genomes of Aegilops, wheat and the model species Brachypodium and rice as revealed by COS markers.

    Directory of Open Access Journals (Sweden)

    István Molnár

    Full Text Available Diploid Aegilops umbellulata and Ae. comosa and their natural allotetraploid hybrids Ae. biuncialis and Ae. geniculata are important wild gene sources for wheat. With the aim of assisting in alien gene transfer, this study provides gene-based conserved orthologous set (COS markers for the U and M genome chromosomes. Out of the 140 markers tested on a series of wheat-Aegilops chromosome introgression lines and flow-sorted subgenomic chromosome fractions, 100 were assigned to Aegilops chromosomes and six and seven duplications were identified in the U and M genomes, respectively. The marker-specific EST sequences were BLAST-ed to Brachypodium and rice genomic sequences to investigate macrosyntenic relationships between the U and M genomes of Aegilops, wheat and the model species. Five syntenic regions of Brachypodium identified genome rearrangements differentiating the U genome from the M genome and from the D genome of wheat. All of them seem to have evolved at the diploid level and to have been modified differentially in the polyploid species Ae. biuncialis and Ae. geniculata. A certain level of wheat-Aegilops homology was detected for group 1, 2, 3 and 5 chromosomes, while a clearly rearranged structure was showed for the group 4, 6 and 7 Aegilops chromosomes relative to wheat. The conserved orthologous set markers assigned to Aegilops chromosomes promise to accelerate gene introgression by facilitating the identification of alien chromatin. The syntenic relationships between the Aegilops species, wheat and model species will facilitate the targeted development of new markers specific for U and M genomic regions and will contribute to the understanding of molecular processes related to allopolyploidization.

  2. Fingering phenomena during grain-grain displacement

    Science.gov (United States)

    Mello, Nathália M. P.; Paiva, Humberto A.; Combe, G.; Atman, A. P. F.

    2016-05-01

    Spontaneous formation of fingered patterns during the displacement of dense granular assemblies was experimentally reported few years ago, in a radial Hele-Shaw cell. Here, by means of discrete element simulations, we have recovered the experimental findings and extended the original study to explore the control parameters space. In particular, using assemblies of grains with different geometries (monodisperse, bidisperse, or polydisperse), we measured the macroscopic stress tensor in the samples in order to confirm some conjectures proposed in analogy with Saffman-Taylor viscous fingering phenomena for immiscible fluids. Considering an axial setup which allows to control the discharge of grains and to follow the trajectory and the pressure gradient along the displacing interface, we have applied the Darcy law for laminar flow in fluids in order to measure an "effective viscosity" for each assembly combination, in an attempt to mimic variation of the viscosity ratio between the injected/displaced fluids in the Saffman-Taylor experiment. The results corroborate the analogy with the viscous fluids displacement, with the bidisperse assembly corresponding to the less viscous geometry. But, differently to fluid case, granular fingers only develop for a specific combination of displaced/injected geometries, and we have demonstrated that it is always related with the formation of a force chain network along the finger direction.

  3. Composite circumstellar dust grains

    Science.gov (United States)

    Gupta, Ranjan; Vaidya, Dipak B.; Dutta, Rajeshwari

    2016-10-01

    We calculate the absorption efficiencies of composite silicate grains with inclusions of graphite and silicon carbide in the spectral range 5-25 μm. We study the variation in absorption profiles with volume fractions of inclusions. In particular we study the variation in the wavelength of peak absorption at 10 and 18 μm. We also study the variation of the absorption of porous silicate grains. We use the absorption efficiencies to calculate the infrared flux at various dust temperatures and compare with the observed infrared emission flux from the circumstellar dust around some M-type and asymptotic giant branch stars obtained from IRAS and a few stars from Spitzer satellite. We interpret the observed data in terms of the circumstellar dust grain sizes, shape, composition and dust temperature.

  4. Composite Circumstellar Dust Grains

    CERN Document Server

    Gupta, Ranjan; Dutta, Rajeshwari

    2016-01-01

    We calculate the absorption efficiencies of composite silicate grains with inclusions of graphite and silicon carbide in the spectral range 5--25$\\rm \\mu m$. We study the variation in absorption profiles with volume fractions of inclusions. In particular we study the variation in the wavelength of peak absorption at 10 and 18$\\rm \\mu m$. We also study the variation of the absorption of porous silicate grains. We use the absorption efficiencies to calculate the infrared flux at various dust temperatures and compare with the observed infrared emission flux from the circumstellar dust around some M-Type \\& AGB stars obtained from IRAS and a few stars from Spitzer satellite. We interpret the observed data in terms of the circumstellar dust grain sizes; shape; composition and dust temperature.

  5. Whole Grains and Fiber

    Science.gov (United States)

    ... whole grains. Does not contain partially hydrogenated oils. Dietary Fiber Dietary fiber is the term for several materials that make ... water. When eaten regularly as part of a diet low in saturated fat and trans fat soluble fiber has been associated with increased diet quality and ...

  6. Formation on grain surfaces

    NARCIS (Netherlands)

    Cazaux, S; Tielens, AGGM

    2004-01-01

    The most abundant interstellar molecule, H-2, is generally thought to form by recombination of H atoms on grain surfaces. On surfaces, hydrogen atoms can be physisorbed and chemisorbed and their mobility can be governed by quantum mechanical tunneling or thermal hopping. We have developed a model fo

  7. Grain Boundary Segregation in Metals

    CERN Document Server

    Lejcek, Pavel

    2010-01-01

    Grain boundaries are important structural components of polycrystalline materials used in the vast majority of technical applications. Because grain boundaries form a continuous network throughout such materials, their properties may limit their practical use. One of the serious phenomena which evoke these limitations is the grain boundary segregation of impurities. It results in the loss of grain boundary cohesion and consequently, in brittle fracture of the materials. The current book deals with fundamentals of grain boundary segregation in metallic materials and its relationship to the grain boundary structure, classification and other materials properties.

  8. Why Is It Important to Eat Grains, Especially Whole Grains?

    Science.gov (United States)

    ... Nutrients and health benefits Print Share Why is it important to eat grains, especially whole grains? Eating ... diabetes. Fiber is important for proper bowel function. It helps reduce constipation and diverticulosis. Fiber-containing foods ...

  9. Grain rotation mediated by grain boundary dislocations in nanocrystalline platinum

    Science.gov (United States)

    Wang, Lihua; Teng, Jiao; Liu, Pan; Hirata, Akihiko; Ma, En; Zhang, Ze; Chen, Mingwei; Han, Xiaodong

    2014-01-01

    Grain rotation is a well-known phenomenon during high (homologous) temperature deformation and recrystallization of polycrystalline materials. In recent years, grain rotation has also been proposed as a plasticity mechanism at low temperatures (for example, room temperature for metals), especially for nanocrystalline grains with diameter d less than ~15 nm. Here, in tensile-loaded Pt thin films under a high-resolution transmission electron microscope, we show that the plasticity mechanism transitions from cross-grain dislocation glide in larger grains (d>6 nm) to a mode of coordinated rotation of multiple grains for grains with d<6 nm. The mechanism underlying the grain rotation is dislocation climb at the grain boundary, rather than grain boundary sliding or diffusional creep. Our atomic-scale images demonstrate directly that the evolution of the misorientation angle between neighbouring grains can be quantitatively accounted for by the change of the Frank–Bilby dislocation content in the grain boundary. PMID:25030380

  10. Predictive coarse-graining

    Science.gov (United States)

    Schöberl, Markus; Zabaras, Nicholas; Koutsourelakis, Phaedon-Stelios

    2017-03-01

    We propose a data-driven, coarse-graining formulation in the context of equilibrium statistical mechanics. In contrast to existing techniques which are based on a fine-to-coarse map, we adopt the opposite strategy by prescribing a probabilistic coarse-to-fine map. This corresponds to a directed probabilistic model where the coarse variables play the role of latent generators of the fine scale (all-atom) data. From an information-theoretic perspective, the framework proposed provides an improvement upon the relative entropy method [1] and is capable of quantifying the uncertainty due to the information loss that unavoidably takes place during the coarse-graining process. Furthermore, it can be readily extended to a fully Bayesian model where various sources of uncertainties are reflected in the posterior of the model parameters. The latter can be used to produce not only point estimates of fine-scale reconstructions or macroscopic observables, but more importantly, predictive posterior distributions on these quantities. Predictive posterior distributions reflect the confidence of the model as a function of the amount of data and the level of coarse-graining. The issues of model complexity and model selection are seamlessly addressed by employing a hierarchical prior that favors the discovery of sparse solutions, revealing the most prominent features in the coarse-grained model. A flexible and parallelizable Monte Carlo - Expectation-Maximization (MC-EM) scheme is proposed for carrying out inference and learning tasks. A comparative assessment of the proposed methodology is presented for a lattice spin system and the SPC/E water model.

  11. Grain alcohol study: summary

    Energy Technology Data Exchange (ETDEWEB)

    The study has concentrated upon a detailed examination of all considerations involved in the production, use, and marketing of ethyl alcohol (Ethanol) as produced from the fermentation of agricultural grains. Each parameter was examined in the light of current energy markets and trends; new sources and technological, and processes for fermentation, the capability of the agricultural industry to support fermentaton demand; the optimization of value of agricultureal crops; and the efficiencies of combining related industries. Anhydrous (200 proof) ethanol makes an excellent blending component for all present automotive fuels and an excellent octane additive for unleaded fuels in proportions up to 35% without requiring modifications to current engines. There is no difference between ethanol produced by fermentation and ethanol produced synthetically from petroleum. The decision to produce ethanol one way or the other is purely economic. The agricultural industry can support a major expansion in the fermentation industry. The residue (distillers grains) from the fermentation of corn for ethanol is an excellent and economical feed for livestock and poultry. A reliable supply of distillers grains can assist in making the large beef feedlot operations more economically viable. The source materials, fuels, products and by-products of an ethanol plant, beef feedlot, gas biodigester plant, municipal waste recovery plant and a steam generated electrical plant are interrelated and mutually beneficial for energy efficiencies and economic gains when co-located. The study concludes that the establishment of such agricultural-environment industrial energy complexes, would provide a broad range of significant benefits to Indiana.

  12. Grain alcohol study: summary

    Energy Technology Data Exchange (ETDEWEB)

    The study has concentrated upon a detailed examination of all considerations involved in the production, use, and marketing of ethyl alcohol (ethanol) as produced from the fermentation of agricultural grains. Each parameter was examined in the light of current energy markets and trends; new sources and technological, and processes for fermentation, the capability of the agricultural industry to support fermentation demand; the optimizaton of value of agricultural crops; and the efficiencies of combining related industries. Ahydrous (200 proof) ethanol makes an excellent blending component for all present automotive fuels and an excellent octane additive for unleaded fuels in proportions up to 35% without requiring modifications to current engines. There is no difference between ethanol produced by fermentation and ethanol produced synthetically from petroleum. The decision to produce ethanol one way or the other is purely economic. The agricultural industry can support a major expansion in the fermentation industry. The residue (distillers grains) from the fermentation of corn for ethanol is an excellent and economical feed for livestock and poultry. A reliable supply of distillers grain can assist in making the large beef feedlot operations more economically viable. The source materials, fuels, products and by-products of an ethanol plant, beef feedlot, gas biodigester plant, municipal waste recovery plant and a steam generated electrical plant are interrelated and mutually beneficial for energy efficiencies and economic gains when co-located. The study concludes that the establishment of such agricultural- environment industrial energy complexes, would provide a broad range of significant benefits to Indiana.

  13. Grain Destruction in Interstellar Shocks

    OpenAIRE

    1995-01-01

    Interstellar shock waves can erode and destroy grains present in the shocked gas, primarily as the result of sputtering and grain-grain collisions. Uncertainties in current estimates of sputtering yields are reviewed. Results are presented for the simple case of sputtering of fast grains being stopped in cold gas. An upper limit is derived for sputtering of refractory grains in C-type MHD shocks: shock speeds $v_s \\gtrsim 50 \\kms$ are required for return of more than 30\\% of the silicate to t...

  14. Whole grains and human health.

    Science.gov (United States)

    Slavin, Joanne

    2004-06-01

    Epidemiological studies find that whole-grain intake is protective against cancer, CVD, diabetes, and obesity. Despite recommendations to consume three servings of whole grains daily, usual intake in Western countries is only about one serving/d. Whole grains are rich in nutrients and phytochemicals with known health benefits. Whole grains have high concentrations of dietary fibre, resistant starch, and oligosaccharides. Whole grains are rich in antioxidants including trace minerals and phenolic compounds and these compounds have been linked to disease prevention. Other protective compounds in whole grains include phytate, phyto-oestrogens such as lignan, plant stanols and sterols, and vitamins and minerals. Published whole-grain feeding studies report improvements in biomarkers with whole-grain consumption, such as weight loss, blood-lipid improvement, and antioxidant protection. Although it is difficult to separate the protective properties of whole grains from dietary fibre and other components, the disease protection seen from whole grains in prospective epidemiological studies far exceeds the protection from isolated nutrients and phytochemicals in whole grains.

  15. Alternative grains in nutrition

    Directory of Open Access Journals (Sweden)

    Jevcsák Sz.

    2016-12-01

    Full Text Available Many people suffer from gluten sensitivity or gluten intolerance. They have to avoid or limit their gluten intake. Sorghum and millet are gluten-free cereals, wherefore persons with gluten sensitivity or gluten intolerance could consume them. Moreover, they have a lot of positive effects due to their phenolic compounds as phenol acid or flavonoid. Antioxidant activity in sorghum is especially high in comparison with other cereals. Our aim was to compare literature data about the chemical compositions of sorghum and millet with other grains.

  16. Good Grains Gone Bad: How Grain to Grain Interactions Complicate the Onset of Motion

    Science.gov (United States)

    Yager, E.; Schmeeckle, M. W.

    2015-12-01

    Predictions of the onset of sediment motion are integral components of bed stability and bedload flux estimates. Mechanistic equations for initial motion employ a balance between driving and resisting forces. Driving forces are modeled as functions of the magnitude and duration of turbulence events whereas resisting forces are simply approximated by the grain weight and a static friction angle. Such resistance approximations do not include the effects of grain packing and dynamic interactions with surrounding sediment. To better understand and quantify grain resistance, we used a Discrete Element Method (DEM) model for a single test grain surrounded by a bed of smaller grains. We applied a constant external force on the test grain in each run and progressively increased the force between runs until the test grain moved out of its resting pocket. The DEM model calculated the test grain velocity, position and net force (sum of applied external force and forces from other grains) at time steps of 1×10-7 s. Despite applying a constant external force, the net force on the test grain fluctuated by three to six orders of magnitude, depending on the run. These fluctuations were driven by the creation and destruction of force chains, and the rearrangement of the positions of surrounding bed sediment. Stick-slip behavior, which has been observed in shear tests of granular material, occurred during test-grain motion. The frequency of stick-slip behavior generally declined with higher applied external forces. Therefore, the onset of grain motion was not continuous, as is often assumed even in the presence of fluctuating applied fluid forces. The duration and magnitude of turbulence fluctuations have received considerable attention but our results suggest that grain resistance oscillations are also important. Whether turbulence and resistance fluctuations are synchronous will likely dictate if grain movement occurs, and we are currently conducting model runs to better

  17. Germinated grains: a superior whole grain functional food?

    Science.gov (United States)

    Nelson, Kristina; Stojanovska, Lily; Vasiljevic, Todor; Mathai, Michael

    2013-06-01

    Grains are global dietary staples that when consumed in whole grain form, offer considerable health benefits compared with milled grain foods, including reduced body weight gain and reduced cardiovascular and diabetes risks. Dietary patterns, functional foods, and other lifestyle factors play a fundamental role in the development and management of epidemic lifestyle diseases that share risks of developing adverse metabolic outcomes, including hyperglycaemia, hypertension, dyslipidaemia, oxidative stress, and inflammation. Whole grains provide energy, nutrients, fibres, and bioactive compounds that may synergistically contribute to their protective effects. Despite their benefits, the intake of grains appears to be lower than recommended in many countries. Of emerging interest is the application of germination processes, which may significantly enhance the nutritional and bioactive content of grains, as well as improve palatability. Enhancing grain foods in a natural way using germination techniques may therefore offer a practical, natural, dietary intervention to increase the health benefits and acceptability of whole grains, with potentially widespread effects across populations in attenuating adverse lifestyle disease outcomes. Continuing to build on the growing body of in-vitro studies requires substantiation with extended in-vivo trials so that we may further develop our understanding of the potential of germinated grains as a functional food.

  18. Grain charging in protoplanetary discs

    CERN Document Server

    Ilgner, Martin

    2011-01-01

    Recent work identified a growth barrier for dust coagulation that originates in the electric repulsion between colliding particles. Depending on its charge state, dust material may have the potential to control key processes towards planet formation such as MHD (magnetohydrodynamic) turbulence and grain growth which are coupled in a two-way process. We quantify the grain charging at different stages of disc evolution and differentiate between two very extreme cases: compact spherical grains and aggregates with fractal dimension D_f = 2. Applying a simple chemical network that accounts for collisional charging of grains, we provide a semi-analytical solution. This allowed us to calculate the equilibrium population of grain charges and the ionisation fraction efficiently. The grain charging was evaluated for different dynamical environments ranging from static to non-stationary disc configurations. The results show that the adsorption/desorption of neutral gas-phase heavy metals, such as magnesium, effects the ...

  19. Grain Handling and Storage Safety

    OpenAIRE

    Webster, Jill, Ph.D.

    2005-01-01

    Agricultural Health and Safety Fact Sheet AHS-02 Grain Handling and Storage Safety Jill Webster Ph.D., S. Christian Mariger, Graduate Assistant Agricultural Systems Technology and Education There are several hazards that should be considered when working with grain. Storage structures, handling equipment, and the grain itself have all caused serious injuries and deaths. Storage structures (bins, silos, and granaries), like all confined spaces, have significant hazards associated with them. Be...

  20. Urbanization and Grain Production Efficiency

    Institute of Scientific and Technical Information of China (English)

    Xiaoyang; LI; Dongge; LIU

    2015-01-01

    Based on DEA-Malmquist method,this paper calculated the integrated technology efficiency of grain production and total factor productivity and analyzed factors influencing the grain production technology efficiency using working documents of panel structure. Research results indicate that grain production integrated technology efficiency of China is relatively low,technology utilization level is low,and it remains at the stage of decreasing returns to scale,and the pure technology efficiency still has space to increase. Total factor productivity is declining and the total factor productivity of many provinces is relatively low. Since the total factor productivity of eastern areas is higher than central and western areas,it is required to strengthen technological support for grain production. The implementation of urbanization is helpful for promoting increase of grain production technology efficiency in central and eastern areas,but it will exert negative influence on western areas.

  1. Autonomous grain combine control system

    Science.gov (United States)

    Hoskinson, Reed L.; Kenney, Kevin L.; Lucas, James R.; Prickel, Marvin A.

    2013-06-25

    A system for controlling a grain combine having a rotor/cylinder, a sieve, a fan, a concave, a feeder, a header, an engine, and a control system. The feeder of the grain combine is engaged and the header is lowered. A separator loss target, engine load target, and a sieve loss target are selected. Grain is harvested with the lowered header passing the grain through the engaged feeder. Separator loss, sieve loss, engine load and ground speed of the grain combine are continuously monitored during the harvesting. If the monitored separator loss exceeds the selected separator loss target, the speed of the rotor/cylinder, the concave setting, the engine load target, or a combination thereof is adjusted. If the monitored sieve loss exceeds the selected sieve loss target, the speed of the fan, the size of the sieve openings, or the engine load target is adjusted.

  2. Coarse Grained Quantum Dynamics

    CERN Document Server

    Agon, Cesar; Kasko, Skyler; Lawrence, Albion

    2014-01-01

    We consider coarse graining a quantum system divided between short distance and long distance degrees of freedom, which are coupled by the Hamiltonian. Observations using purely long distance observables can be described by the reduced density matrix that arises from tracing out the short-distance observables. The dynamics of this density matrix is that of an open quantum system, and is nonlocal in time, on the order of some short time scale. We describe these dynamics in a model system with a simple hierarchy of energy gaps $\\Delta E_{UV} > \\Delta E_{IR}$, in which the coupling between high-and low-energy degrees of freedom is treated to second order in perturbation theory. We then describe the equations of motion under suitable time averaging, reflecting the limited time resolution of actual experiments, and find an expansion of the master equation in powers of $\\Delta E_{IR}/\\Delta E_{UV}$, in which the failure of the system to be Hamiltonian or even Markovian appears at higher orders in this ratio. We com...

  3. Quantitative characterisation of sedimentary grains

    Science.gov (United States)

    Tunwal, Mohit; Mulchrone, Kieran F.; Meere, Patrick A.

    2016-04-01

    Analysis of sedimentary texture helps in determining the formation, transportation and deposition processes of sedimentary rocks. Grain size analysis is traditionally quantitative, whereas grain shape analysis is largely qualitative. A semi-automated approach to quantitatively analyse shape and size of sand sized sedimentary grains is presented. Grain boundaries are manually traced from thin section microphotographs in the case of lithified samples and are automatically identified in the case of loose sediments. Shape and size paramters can then be estimated using a software package written on the Mathematica platform. While automated methodology already exists for loose sediment analysis, the available techniques for the case of lithified samples are limited to cases of high definition thin section microphotographs showing clear contrast between framework grains and matrix. Along with the size of grain, shape parameters such as roundness, angularity, circularity, irregularity and fractal dimension are measured. A new grain shape parameter developed using Fourier descriptors has also been developed. To test this new approach theoretical examples were analysed and produce high quality results supporting the accuracy of the algorithm. Furthermore sandstone samples from known aeolian and fluvial environments from the Dingle Basin, County Kerry, Ireland were collected and analysed. Modern loose sediments from glacial till from County Cork, Ireland and aeolian sediments from Rajasthan, India have also been collected and analysed. A graphical summary of the data is presented and allows for quantitative distinction between samples extracted from different sedimentary environments.

  4. An Improved Implementation of Grain

    CERN Document Server

    Mansouri, Shohreh Sharif

    2009-01-01

    A common approach to protect confidential information is to use a stream cipher which combines plain text bits with a pseudo-random bit sequence. Among the existing stream ciphers, Non-Linear Feedback Shift Register (NLFSR)-based ones provide the best trade-off between cryptographic security and hardware efficiency. In this paper, we show how to further improve the hardware efficiency of Grain stream cipher. By transforming the NLFSR of Grain from its original Fibonacci configuration to the Galois configuration and by introducing a clock division block, we double the throughput of the 80 and 128-bit key 1bit/cycle architectures of Grain with no area penalty.

  5. Export Rebates on Grain Finished

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ According to the State Statistics Bureau, China's consumer price index (CPI) jumped by 6.9 percent year-on-year last November, approaching the high levels seen at the end of 1996, one of the largest areas of increase was the price of grain,which rose by 6.6 percent. There is no doubt the growth in CPI can be mainly attributed to soaring food prices and the diffusion effect of oil price adjustments. Large orders for grain exports have put Chinese grain suppliers under tremendous pressure. In order to solve this problem, the Finance Ministry and State Administration of Taxation together announced that 84 categories of export tax rebates on major types of grain will be eliminated.

  6. Export Rebates on Grain Finished

    Institute of Scientific and Technical Information of China (English)

    Liu; Xinwen

    2008-01-01

      According to the State Statistics Bureau, China's consumer price index (CPI) jumped by 6.9 percent year-on-year last November, approaching the high levels seen at the end of 1996, one of the largest areas of increase was the price of grain,which rose by 6.6 percent. There is no doubt the growth in CPI can be mainly attributed to soaring food prices and the diffusion effect of oil price adjustments. Large orders for grain exports have put Chinese grain suppliers under tremendous pressure. In order to solve this problem, the Finance Ministry and State Administration of Taxation together announced that 84 categories of export tax rebates on major types of grain will be eliminated.……

  7. PARASITE MYCOPOPULATION OF SOYBEAN GRAIN

    Directory of Open Access Journals (Sweden)

    Jasenka Ćosić

    2008-07-01

    Full Text Available Disease appearance on soybean can influence quality and quantity of yield. Different spieces of saprophyte and parasite fungi can be isolated from stems, pods and grain of soybean. The aim of the research was to evaluate the incidence of important disease on natural soybean grain over the period of 4 years (2004-2007 of experiment held on the location Sopot-Vinkovci and included 9 cultivars of soybean. The following plant pathogenic fungi were identified: Peronospora, Sclerotinia, Cercospora, Fusarium and Diaporthe/Phomopsis. The most frequent fungi on soybean grains were: Cladosporium, Alternaria, Penicillium, Aspergillus and Epicoccum. The health condition of the natural soybean grains over the four years period on all cultivars was good.

  8. PARASITE MYCOPOPULATION OF SOYBEAN GRAIN

    OpenAIRE

    Jasenka Ćosić; Karolina Vrandečić; Draženka Jurković; Ivan Ereš; Jelena Poštić

    2008-01-01

    Disease appearance on soybean can influence quality and quantity of yield. Different spieces of saprophyte and parasite fungi can be isolated from stems, pods and grain of soybean. The aim of the research was to evaluate the incidence of important disease on natural soybean grain over the period of 4 years (2004-2007) of experiment held on the location Sopot-Vinkovci and included 9 cultivars of soybean. The following plant pathogenic fungi were identified: Peronospora, Sclerotinia, Cercospora...

  9. Superconductivity of small metal grains

    Institute of Scientific and Technical Information of China (English)

    ZHENG; Renrong; CHEN; Zhiqian; ZHU; Shunquan

    2005-01-01

    The formulas of the energy gap and superconducting critical temperature appropriate for systems with both odd and even number of electrons are derived; the bases of the derivations are BCS theory and energy level statistics. Numerical results qualitatively agree with the experimental phenomena. i.e., the superconductivity of small metallic grains will first enhance then decrease to zero when the grain are getting smaller and smaller. The calculations indicate that the above phenomena happen in the metallic grains belonging to Gaussian Orthogonal Ensemble (GOE) and Gaussian Unitary ensemble (GUE) with zero spin; The superconductivity of small metallic grains in Gaussian Symplectic Ensemble (GSE) will monotonically decrease to zero with the decreasing of the grain size. The analyses suggest that the superconductivity enhancements come from pairing and the balance of the strengths between spin-orbital coupling and external magnetic field. In order to take the latter into account, it is necessary to include the level statistics given by Random Matrix Theory (RMT) in describing small metallic grains.

  10. Protein (Viridiplantae): 357148991 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 024:1950 3398:1950 4447:782 4734:782 38820:782 4479:782 359160:428 147368:988 147385:988 15367:988 15368:988 PREDICTED: putative adag...io-like protein 2-like Brachypodium distachyon MEWDSDSDGGSGDEEEEEEGVGPWGGGGGGGGAGFS

  11. Protein (Viridiplantae): 357137776 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available ctomannan galactosyltransferase 1-like Brachypodium distachyon MARALGDALLFSAGAAVATV...024:2964 3398:2964 4447:4420 4734:4420 38820:4420 4479:4420 359160:2412 147368:2211 147385:2211 15367:2211 15368:2211 PREDICTED: gala

  12. Protein (Viridiplantae): 357152031 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available ctomannan galactosyltransferase 1-like Brachypodium distachyon MASESAPFCLSGTGGGKGAA...024:2964 3398:2964 4447:4420 4734:4420 38820:4420 4479:4420 359160:2412 147368:2211 147385:2211 15367:2211 15368:2211 PREDICTED: gala

  13. Protein (Viridiplantae): 357112985 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 58024:7047 3398:7047 4447:4465 4734:4465 38820:4465 4479:4465 359160:2518 147368:2334 147385:2334 15367:2334... 15368:2334 PREDICTED: josephin-like protein-like Brachypodium distachyon MEPGAKSEANQNEEGSGAVGSSGGSSKVYHERQR

  14. Protein (Viridiplantae): 357148126 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 5 15368:6125 PREDICTED: IMPACT family member in pol 5'region-like Brachypodium distachyon MAAVRVVTPRLRSIPLLL...8024:15552 3398:15552 4447:7995 4734:7995 38820:7995 4479:7995 359160:5958 147368:6125 147385:6125 15367:612

  15. Protein (Viridiplantae): 357130643 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 121 3398:3121 4447:340 4734:340 38820:340 4479:340 359160:3145 147368:3033 147385:3033 15367:3033 15368:3033 PREDICTED: Werner Syndro...me-like exonuclease-like Brachypodium distachyon MATDTYVTDVTFEENVIITTVTSSGVAVEGWLRE

  16. Protein (Viridiplantae): 357132051 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 15368:4872 PREDICTED: craniofacial development protein 1-like Brachypodium distachyon MASRSSASEAGGSGAKVVAAD...58024:4234 3398:4234 4447:6074 4734:6074 38820:6074 4479:6074 359160:4801 147368:4872 147385:4872 15367:4872

  17. Protein (Viridiplantae): 357135844 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 8024:5377 3398:5377 4447:5981 4734:5981 38820:5981 4479:5981 359160:5029 147368:5115 147385:5115 15367:5115 15368:5115 PREDICTED: bor...on transporter 4-like Brachypodium distachyon MDLLRNPFKGVVADVKGRASWYKDDWVAGLRAGFRIL

  18. Protein (Viridiplantae): 357134432 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 8024:5377 3398:5377 4447:5981 4734:5981 38820:5981 4479:5981 359160:5029 147368:5115 147385:5115 15367:5115 15368:5115 PREDICTED: bor...on transporter 4-like Brachypodium distachyon MEHKKTLFKGVIEDFRGRAACYKQDWHNGFSSGFRIL

  19. A synteny-based draft genome sequence of the forage grass Lolium perenne

    DEFF Research Database (Denmark)

    Byrne, Stephen; Nagy, Istvan; Pfeifer, Matthias;

    2015-01-01

    Here we report the draft genome sequence of perennial ryegrass (Lolium perenne), an economically important forage and turf grass species that is widely cultivated in temperate regions worldwide. It is classified along with wheat, barley, oats and Brachypodium distachyon in the Pooideae sub-family...

  20. Protein (Viridiplantae): 357168326 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available :7145 PREDICTED: craniofacial development protein 2-like Brachypodium distachyon MKPKRISLGRNPLSDAPYRNPGVVSNG...2 3398:112 4447:10886 4734:10886 38820:10886 4479:10886 359160:6892 147368:7145 147385:7145 15367:7145 15368

  1. Protein (Viridiplantae): 357117309 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 327 PREDICTED: protein UNUSUAL FLORAL ORGANS-like Brachypodium distachyon MINNNRHHQLPLPSSIVSSVQHHPSHSQLSSPTP...24:4516 3398:4516 4447:2114 4734:2114 38820:2114 4479:2114 359160:480 147368:327 147385:327 15367:327 15368:

  2. Protein (Viridiplantae): 357130639 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 121 3398:3121 4447:340 4734:340 38820:340 4479:340 359160:3145 147368:3033 147385:3033 15367:3033 15368:3033 PREDICTED: Werner Syndro...me-like exonuclease-like Brachypodium distachyon MAITYHAPRQVASGRRSRADKIHTDVIMDDGTSI

  3. Protein (Viridiplantae): 357120544 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 121 3398:3121 4447:340 4734:340 38820:340 4479:340 359160:3145 147368:3033 147385:3033 15367:3033 15368:3033 PREDICTED: Werner Syndro...me-like exonuclease-like Brachypodium distachyon MTTARYTVRFSSALIDTTVTSDAAAADEWARSVR

  4. Protein (Viridiplantae): 357130647 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 121 3398:3121 4447:340 4734:340 38820:340 4479:340 359160:3145 147368:3033 147385:3033 15367:3033 15368:3033 PREDICTED: Werner Syndro...me-like exonuclease-like Brachypodium distachyon MATETYVTPVAFEGYVITATVTSSGKAVEDWIQE

  5. Protein (Viridiplantae): 357130641 [PGDBj - Ortholog DB

    Lifescience Database Archive (English)

    Full Text Available 121 3398:3121 4447:340 4734:340 38820:340 4479:340 359160:3145 147368:3033 147385:3033 15367:3033 15368:3033 PREDICTED: Werner Syndro...me-like exonuclease-like Brachypodium distachyon MAATRVTHVASPLEEGSVIICTVTSSGNAAAAWV

  6. Grain dynamics in zero gravity

    Science.gov (United States)

    Werner, B. T.; Haff, P. K.

    1987-01-01

    The dynamics of granular materials has proved difficult to model, primarily because of the complications arising from inelastic losses, friction, packing, and the effect of many grains being in contact simultaneously. One interesting limit for which it was recently possible to construct a theory is that where the grain-grain interactions are dominated by binary collisions. The kinetic model of granular systems if similar to the kinetic theory of gases, except that collisional energy losses are always present in the former and must be treated explicitly. Few granular materials on Earth are describable by this limiting model, since gravity tends to collapse the grains into a high-density state where Coulombic friction effects are dominant. The planned Space Station offers an unusual opportunity to test the kinetic grain model and to explore its predictions. Without gravity, the regime of low interparticle velocities, where an elastic description of the collision is still valid, is investigated. This will allow direct interpretation by dynamical computer simulations as well as by kinetic theory.

  7. Deformation strain inhomogeneity in columnar grain nickel

    DEFF Research Database (Denmark)

    Wu, G.L.; Godfrey, A.; Juul Jensen, D.

    2005-01-01

    A method is presented for determination of the local deformation strain of individual grains in the bulk of a columnar grain sample. The method, based on measurement of the change in grain area of each grain, is applied to 12% cold rolled nickel. Large variations are observed in the local strain...

  8. Interstellar Grains: 50 Years On

    CERN Document Server

    Wickramasinghe, N Chandra

    2011-01-01

    Our understanding of the nature of interstellar grains has evolved considerably over the past half century with the present author and Fred Hoyle being intimately involved at several key stages of progress. The currently fashionable graphite-silicate-organic grain model has all its essential aspects unequivocally traceable to original peer-reviewed publications by the author and/or Fred Hoyle. The prevailing reluctance to accept these clear-cut priorities may be linked to our further work that argued for interstellar grains and organics to have a biological provenance - a position perceived as heretical. The biological model, however, continues to provide a powerful unifying hypothesis for a vast amount of otherwise disconnected and disparate astronomical data.

  9. Grain centre mapping - 3DXRD measurements of average grain characteristics

    DEFF Research Database (Denmark)

    Oddershede, Jette; Schmidt, Søren; Lyckegaard, Allan;

    2014-01-01

    Three-Dimensional X-ray Diraction (3DXRD) Microscopy is a generic term covering a variety of dierent techniques for characterising the mi- crostructure within the bulk of polycrystalline materials. One strategy | namely grain centre mapping | enables fast measurements of the av- erage characteris...

  10. AGB stars and presolar grains

    CERN Document Server

    Busso, M; Maiorca, E; Palmerini, S

    2013-01-01

    Among presolar materials recovered in meteorites, abundant SiC and Al$_{2}$O$_{3}$ grains of AGB origins were found. They showed records of C, N, O, $^{26}$Al and s-element isotopic ratios that proved invaluable in constraining the nucleosynthesis models for AGB stars \\cite{zin,gal}. In particular, when these ratios are measured in SiC grains, they clearly reveal their prevalent origin in cool AGB circumstellar envelopes and provide information on both the local physics and the conditions at the nucleosynthesis site (the H- and He-burning layers deep inside the structure). Among the properties ascertained for the main part of the SiC data (the so-called {\\it mainstream} ones), we mention a large range of $^{14}$N/$^{15}$N ratios, extending below the solar value \\cite{mar}, and $^{12}$C/$^{13}$C ratios $\\gtrsim$ 30. Other classes of grains, instead, display low carbon isotopic ratios ($\\gtrsim 10$) and a huge dispersion for N isotopes, with cases of large $^{15}$N excess. In the same grains, isotopes currently...

  11. Concepts on Low Temperature Mechanical Grain Growth

    Energy Technology Data Exchange (ETDEWEB)

    Sharon, John Anthony [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Metallurgy and Materials Joining Dept.; Boyce, Brad Lee [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Metallurgy and Materials Joining Dept.

    2013-11-01

    In metals, as grain size is reduced below 100nm, conventional dislocation plasticity is suppressed resulting in improvements in strength, hardness, and wears resistance. Existing and emerging components use fine grained metals for these beneficial attributes. However, these benefits can be lost in service if the grains undergo growth during the component’s lifespan. While grain growth is traditionally viewed as a purely thermal process that requires elevated temperature exposure, recent evidence shows that some metals, especially those with nanocrystalline grain structure, can undergo grain growth even at room temperature or below due to mechanical loading. This report has been assembled to survey the key concepts regarding how mechanical loads can drive grain coarsening at room temperature and below. Topics outlined include the atomic level mechanisms that facilitate grain growth, grain boundary mobility, and the impact of boundary structure, loading scheme, and temperature.

  12. AGB stars and presolar grains

    Energy Technology Data Exchange (ETDEWEB)

    Busso, M.; Trippella, O. [INFN and University of Perugia, Perugia (Italy); Maiorca, E. [INAF - Arcetri Astrophysical Observatory, Firenze, Italy and INFN - Section of Perugia, Perugia (Italy); Palmerini, S. [Departamento de Fìsica Teòrica y del Cosmsos, Universidad de Granada, Granada (Spain)

    2014-05-09

    Among presolar materials recovered in meteorites, abundant SiC and Al{sub 2}O{sub 3} grains of AGB origins were found. They showed records of C, N, O, {sup 26}Al and s-element isotopic ratios that proved invaluable in constraining the nucleosynthesis models for AGB stars [1, 2]. In particular, when these ratios are measured in SiC grains, they clearly reveal their prevalent origin in cool AGB circumstellar envelopes and provide information on both the local physics and the conditions at the nucleosynthesis site (the H- and He-burning layers deep inside the structure). Among the properties ascertained for the main part of the SiC data (the so-called mainstream ones), we mention a large range of {sup 14}N/{sup 15}N ratios, extending below the solar value [3], and {sup 12}C/{sup 13}C ratios ≳ 30. Other classes of grains, instead, display low carbon isotopic ratios (≳ 10) and a huge dispersion for N isotopes, with cases of large {sup 15}N excess. In the same grains, isotopes currently feeded by slow neutron captures reveal the characteristic pattern expected from this process at an efficiency slightly lower than necessary to explain the solar main s-process component. Complementary constraints can be found in oxide grains, especially Al{sub 2}O{sub 3} crystals. Here, the oxygen isotopes and the content in {sup 26}Al are of a special importance for clarifying the partial mixing processes that are known to affect evolved low-mass stars. Successes in modeling the data, as well as problems in explaining some of the mentioned isotopic ratios through current nucleosynthesis models are briefly outlined.

  13. Grain Refinement of Deoxidized Copper

    Science.gov (United States)

    Balart, María José; Patel, Jayesh B.; Gao, Feng; Fan, Zhongyun

    2016-10-01

    This study reports the current status of grain refinement of copper accompanied in particular by a critical appraisal of grain refinement of phosphorus-deoxidized, high residual P (DHP) copper microalloyed with 150 ppm Ag. Some deviations exist in terms of the growth restriction factor ( Q) framework, on the basis of empirical evidence reported in the literature for grain size measurements of copper with individual additions of 0.05, 0.1, and 0.5 wt pct of Mo, In, Sn, Bi, Sb, Pb, and Se, cast under a protective atmosphere of pure Ar and water quenching. The columnar-to-equiaxed transition (CET) has been observed in copper, with an individual addition of 0.4B and with combined additions of 0.4Zr-0.04P and 0.4Zr-0.04P-0.015Ag and, in a previous study, with combined additions of 0.1Ag-0.069P (in wt pct). CETs in these B- and Zr-treated casts have been ascribed to changes in the morphology and chemistry of particles, concurrently in association with free solute type and availability. No further grain-refining action was observed due to microalloying additions of B, Mg, Ca, Zr, Ti, Mn, In, Fe, and Zn (~0.1 wt pct) with respect to DHP-Cu microalloyed with Ag, and therefore are no longer relevant for the casting conditions studied. The critical microalloying element for grain size control in deoxidized copper and in particular DHP-Cu is Ag.

  14. Cool Down!——The State Administration of Grain Lower Expectation of Grain Price

    Institute of Scientific and Technical Information of China (English)

    He Jun

    2010-01-01

    @@ The rising grain price in the first half of the year,coupled with the news that China's summer grain output fell for the first time in seven years,has enhanced market expectation for the grain price to rise.

  15. Spinodal decomposition in fine grained materials

    Indian Academy of Sciences (India)

    H Ramanarayan; T A Abinandanan

    2003-01-01

    We have used a phase field model to study spinodal decomposition in polycrystalline materials in which the grain size is of the same order of magnitude as the characteristic decomposition wavelength ($\\lambda_{SD}$). In the spirit of phase field models, each grain () in our model has an order parameter ($\\eta_i$) associated with it; $\\eta_i$ has a value of unity inside the th grain, decreases smoothly through the grain boundary region to zero outside the grain. For a symmetric alloy of composition, = 0.5, our results show that microstructural evolution depends largely on the difference in the grain boundary energies, $\\gamma_{gb}$, of A-rich () and B-rich () phases. If $\\gamma^{\\alpha}_{gb}$ is lower, we find that the decomposition process is initiated with an layer being formed at the grain boundary. If the grain size is sufficiently small (about the same as $\\lambda_{SD}$), the interior of the grain is filled with the phase. If the grain size is large (say, about 10 $\\lambda_{SD}$ or greater), the early stage microstructure exhibits an A-rich grain boundary layer followed by a B-rich layer; the grain interior exhibits a spinodally decomposed microstructure, evolving slowly. Further, grain growth is suppressed completely during the decomposition process.

  16. Coarse-graining complex dynamics

    DEFF Research Database (Denmark)

    Sibani, Paolo

    2013-01-01

    Continuous Time Random Walks (CTRW) are widely used to coarse-grain the evolution of systems jumping from a metastable sub-set of their configuration space, or trap, to another via rare intermittent events. The multi-scaled behavior typical of complex dynamics is provided by a fat-tailed distribu......Continuous Time Random Walks (CTRW) are widely used to coarse-grain the evolution of systems jumping from a metastable sub-set of their configuration space, or trap, to another via rare intermittent events. The multi-scaled behavior typical of complex dynamics is provided by a fat......-law and logarithmic relaxation behaviors ubiquitous in complex dynamics, together with the sub-diffusive time dependence of the Mean Square Displacement characteristic of single particles moving in a complex environment....

  17. Molecule Formation on Interstellar Grains

    Science.gov (United States)

    Vidali, G.

    2011-05-01

    The first experiments that were expressively designed to be applicable to hydrogen formation reactions in the ISM measured the efficiency of formation of molecular hydrogen on a polycrystalline olivine (Pirronello et al. (1997a)). It soon turned out that more was needed, and research began on the mechanism of reaction, on the in uence of the surface morphology, and on the excitation of the just- ormed molecule. In this review, I summarize what we learned from these and other experiments, and where more work is needed: in the elementary steps of reaction, in the bridging of the laboratory-ISM gap (large ux/large surface - small ux/small grain) using simulations, and in using realistic samples of dust grains. Understanding what experiments can and cannot deliver will help in designing and targeting observations, and vice-versa.

  18. Solid Propellant Grain Structural Integrity Analysis

    Science.gov (United States)

    1973-01-01

    The structural properties of solid propellant rocket grains were studied to determine the propellant resistance to stresses. Grain geometry, thermal properties, mechanical properties, and failure modes are discussed along with design criteria and recommended practices.

  19. Efficient radiative transfer in dust grain mixtures

    CERN Document Server

    Wolf, S

    2003-01-01

    The influence of a dust grain mixture consisting of spherical dust grains with different radii and/or chemical composition on the resulting temperature structure and spectral energy distribution of a circumstellar shell is investigated. The comparison with the results based on an approximation of dust grain parameters representing the mean optical properties of the corresponding dust grain mixture reveal that (1) the temperature dispersion of a real dust grain mixture decreases substantially with increasing optical depth, converging towards the temperature distribution resulting from the approximation of mean dust grain parameters, and (2) the resulting spectral energy distributions do not differ by more than 10% if >= 2^5 grain sizes are considered which justifies the mean parameter approximation and the many results obtained under its assumption so far. Nevertheless, the dust grain temperature dispersion at the inner boundary of a dust shell may amount to >>100K and has therefore to be considered in the cor...

  20. Automatic Coarse Graining of Polymers

    OpenAIRE

    Faller, Roland

    2003-01-01

    Several recently proposed semi--automatic and fully--automatic coarse--graining schemes for polymer simulations are discussed. All these techniques derive effective potentials for multi--atom units or super--atoms from atomistic simulations. These include techniques relying on single chain simulations in vacuum and self--consistent optimizations from the melt like the simplex method and the inverted Boltzmann method. The focus is on matching the polymer structure on different scales. Several ...

  1. Grain boundary wetness of partially molten dunite

    Science.gov (United States)

    Mu, S.; Faul, U.

    2013-12-01

    The grain scale melt distribution plays a key role for physical properties of partially molten regions in Earth's upper mantle, but our current understanding of the distribution of basaltic melt at the grain scale is still incomplete. A recent experimental study shows that wetted two-grain boundaries are a common feature of partially molten dunite at small melt fractions (Garapic et al., G3, 2013). In early ideal models which assume isotropic surface energy, the grain scale melt distribution is uniquely determined by knowing the melt fraction and the dihedral angle between two crystalline grains and the melt (von Bargen and Waff, JGR, 1986). Olivine is anisotropic in surface energy, hence the grain scale melt distribution at given melt fraction cannot be characterized by the dihedral angle alone. The grain boundary wetness, which is defined as the ratio of solid-liquid boundary area over the total interfacial area (Takei, JGR, 1998), is a more objective measure of the grain scale melt distribution. The aim of this study is to quantify the relationship between grain size, melt fraction, temperature and grain boundary wetness of partially molten dunite under dry conditions. We annealed olivine-basalt aggregates with melt fractions from 0.03% to 6% at a range of temperatures and 1 GPa in a piston cylinder for 1 to 336 hours, with resulting mean grain sizes of 10 to 60 μm. The samples were sectioned, polished and imaged at high resolution by using a field emission SEM. Each image had a size of 2048 x 1536 pixels with a resolution of 0.014 to 0.029 μm/pixel, depending on magnification. For each sample, depending on grain sizes, we made mosaics of 3 x 3 or 6 x 6 overlapping images. Measurements of melt fraction, grain boundary wetness and grain size were carried out on these high resolution mosaics by using ImageJ software. Analyses of mosaics show that grain boundary wetness increases with increasing melt fraction at constant grain size to values well above those

  2. Grain Boundary Energies in Copper.

    Science.gov (United States)

    Omar, Ramli

    Available from UMI in association with The British Library. Requires signed TDF. The dependence of grain boundary energy on boundary orientation was studied in copper annealed at 1000 ^circC. Grain boundary orientations and the disorientations across the boundaries were measured. A rotation matrix notation is used to interpret selected area electron channelling patterns observed in a scanning electron microscope. The Herring and Shewmon torque terms were investigated using wire specimens having a "bamboo" structure. The Herring torque terms were determined using the Hess relation. The (110) section of the Sigma 11 gamma-plot (i.e. the variation of grain boundary energy with boundary orientation) was evaluated. In this plot, minima in energies were found at the (311) and (332) mirror planes. Sigma 3 and Sigma9 boundaries were investigated in sheet specimens. The (110) and (111) sections of the Sigma3 gamma -plot were evaluated. In addition to the sharp cusps occurring at the Sigma3 {111} planes, the further shallower cusps occur at the incoherent Sigma 3 boundaries with the interfacial planes approximately parallel to {322} in one crystal and {11.44} in the other crystal. Flat and curved Sigma9 boundaries were investigated. The break up of Sigma9 boundaries into two Sigma3 boundaries and the relation between the Sigma3 and Sigma 9 gamma-plots was also examined. The (110) section of the Sigma9 gamma-plot was constructed.

  3. Whole grains: benefits and challenges.

    Science.gov (United States)

    Jones, Julie Miller; Engleson, Jodi

    2010-01-01

    Inclusion of whole grains (WG) in the diet is recommended in dietary guidance around the world because of their associations with increased health and reduced risk of chronic disease. WGs are linked to reduced risk of obesity or weight gain; reduced risk of cardiovascular disease (CVD), including coronary heart disease (CHD), hypertension, and stroke; improved gut health and decreased risk of cancers of the upper gut; perhaps reduced risk of colorectal cancer; and lower mortality rate. The 2005 United States Dietary Guidelines Advisory Committee has recommended that consumers make "half their grains whole." Yet, whole grains are puzzling both consumers and scientists. Scientists are trying to determine whether their health benefits are due to the synergy of WG components, individual WG components, or the fact that WG eaters make many of the recommended diet and lifestyle choices. Consumers need to understand the WG benefits and how to identify WG foods to have incentive to purchase and use such foods. Industry needs to develop great-tasting, clearly-labeled products. With both these factors working together, it will be possible to change WG consumption habits among consumers.

  4. Grain Boundary (GB) Studies in Nano- and Micro- Crystalline Materials

    OpenAIRE

    Tanju, Mst Sohanazaman

    2011-01-01

    Polycrystalline materials are composed of grains and grain boundaries. The total volume of occupied grain boundaries in polycrystalline material depends on the grain size. When grain size decreases the volume fraction of grain boundaries increases. For example, when grain size is 10 nm grain boundary volume fraction is ~ 25%. In polycrystalline materials, different properties (mechanical, electrical, optical, magnetic) are affected by the size of their grains and by the atomic structure of...

  5. Whole grain gluten-free flat breads

    Science.gov (United States)

    The USDA food guide recommends that at least ½ of all the grains eaten should be whole grains. The FDA allows food health claim labels for food containing 51% whole gains and 11 g of dietary fiber. This is the only report demonstrating innovative whole grain gluten free (without yeast or chemicals) ...

  6. Ancient whole grain gluten-free flatbreads

    Science.gov (United States)

    The USDA food guide recommends that at least ½ of all the grains eaten should be whole grains. The FDA allows food Health Claim labels for food containing 51% whole gains and 11 g of dietary fiber. This is the only report demonstrating innovative ancient whole grain gluten-free (no yeast or chemical...

  7. Bioactive compounds in whole grain wheat

    NARCIS (Netherlands)

    Mateo Anson, N.

    2010-01-01

    Bread can be healthier! Consuming whole-grain foods can prevent cardiovascular diseases, type-2 diabetes and metabolic syndrome. This is due to bioactive compounds in whole grain, such as antioxidants and anti-inflammatory compounds. We found that the different fractions of a wheat grain vary much i

  8. Determination of grain boundary geometry using TEM

    NARCIS (Netherlands)

    Jang, H.; Farkas, D.; Hosson, J.T.M. De

    1992-01-01

    An experimental method to obtain the grain boundary geometry using the transmission electron microscope is presented. The method allows Σ determination including grain boundary plane orientation. In order to determine the specialness of the grain boundary, three different criteria for maximum allowa

  9. Weighing in on whole grains: A review of evidence linking whole grains to body weight

    Science.gov (United States)

    U.S. dietary guidelines support the consumption of whole grains in lieu of refined grains. On January 31, 2011, the 2010 Dietary Guidelines for Americans (DGA) were released and the recommendations with respect to grains were for individuals to “Consume at least half of all grains as whole grains” a...

  10. Choosing Whole-Grain Foods: 10 Tips for Purchasing and Storing Whole-Grain Foods

    Science.gov (United States)

    ... Newsroom Dietary Guidelines Communicator’s Guide 10 Tips: Choosing Whole-Grain Foods You are here Home 10 Tips: Choosing Whole-Grain Foods Print Share 10 Tips: Choosing Whole-Grain Foods Whole grains are important sources of nutrients ...

  11. Grain-size sorting and slope failure in experimental subaqueous grain flows

    NARCIS (Netherlands)

    Kleinhans, M.G.; Asch, Th.W.J. van

    2005-01-01

    Grain-size sorting in subaqueous grain flows of a continuous range of grain sizes is studied experimentally with three mixtures. The observed pattern is a combination of stratification and gradual segregation. The stratification is caused by kinematic sieving in the grain flow. The segregation is ca

  12. Spinodal decomposition in fine grained materials

    OpenAIRE

    Ramanarayan, H.; Abinandanan, TA

    2003-01-01

    We have used a phase field model to study spinodal decomposition in polycrystalline materials in which the grain size is of the same order of magnitude as the characteristic decomposition wavelength (lambda(SD))In the spirit of phase field models, each grain (i) in our model has an order parameter (eta(i)) associated with it; eta(i) has a value of unity inside the ith grain, decreasessmoothly through the grain boundary region to zero outside the grain. For a symmetric alloy of composition, c ...

  13. 3D modeling of metallic grain growth

    Energy Technology Data Exchange (ETDEWEB)

    George, D.; Carlson, N.; Gammel, J.T.; Kuprat, A.

    1999-06-01

    This paper will describe simulating metallic grain growth using the Gradient Weighted Moving Finite Elements code, GRAIN3D. The authors also describe the set of mesh topology change operations developed to respond to changes in the physical topology such as the collapse of grains and to maintain uniform calculational mesh quality. Validation of the method is demonstrated by comparison to analytic calculations. The authors present results of multigrain simulations where grain boundaries evolve by mean curvature motion and include results which incorporate grain boundary orientation dependence.

  14. Subsonic Mechanical Alignment of Irregular Grains

    CERN Document Server

    Lazarian, Alex

    2007-01-01

    We show that grains can be efficiently aligned by interacting with a subsonic gaseous flow. The alignment arises from grains having irregularities that scatter atoms with different efficiency in the right and left directions. The grains tend to align with long axes perpendicular to magnetic field, which corresponds to Davis-Greenstein predictions, but does not involve magnetic field. For rather conservative factors characterizing the grain helicity and scattering efficiency of impinging atoms, the alignment of helical grains is much more efficient than the Gold-type alignment processes.

  15. Airborne Pollen Grains Of Afyon, Turkey

    Institute of Scientific and Technical Information of China (English)

    Adem BICAKCI; Süheyla ERGUN; Sevcan TATLIDIL; Hulusi MALYER; Sabri OZYURT; Ahmet AKKAYA; Nihat SAPAN

    2002-01-01

    The airborne pollen grains of Afyon have been studied for a two-year period (1999-2000) with a Durham sampler. A total of 14 367 pollen grains belonging to 40 taxa have been identified and recorded with some unidentified ones. Of them, 6 732 were identified in 1999 and 7 635 in 2000. Of the total pollen grains, 69.67% were arboreal, 26.64% non-arboreal and 3.68 % unidentified. The majority of the investigated pollen grains were from Pinus, Gramineae, Cupressaceae, Platanus, Chenopodiaceae/Amaranthaceae, Quercus, Ailanthus, Moraceae, Juglans, Salix, Cedrus and Rosaceae. The highest level of pollen grains was in May.

  16. Establishment of Grain Farmers’ Supply Response Model and Empirical Analysis under Minimum Grain Purchase Price Policy

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Based on farmers’ supply behavior theory and price expectations theory,this paper establishes grain farmers’ supply response model of two major grain varieties (early indica rice and mixed wheat) in the major producing areas,to test whether the minimum grain purchase price policy can have price-oriented effect on grain production and supply in the major producing areas. Empirical analysis shows that the minimum purchase price published annually by the government has significant positive impact on farmers’ grain supply in the major grain producing areas. In recent years,China steadily raises the level of minimum grain purchase price,which has played an important role in effectively protecting grain farmers’ interests,mobilizing the enthusiasm of farmers’ grain production,and ensuring the market supply of key grain varieties.

  17. Nonresonant Grain Acceleration in MHD Turbulence

    CERN Document Server

    Yan, Huirong

    2009-01-01

    We discuss a new type of dust acceleration mechanism that acts in a turbulent magnetized medium. The magnetohydrodynamic (MHD) turbulence can accelerate grains through resonant as well as nonresonant interactions. We show that the magnetic compression provides higher velocities for super-Alfv\\'enic turbulence and can accelerate an extended range of grains in warm media compared to gyroresonance. While fast modes dominate the acceleration for the large grains, slow modes can be important for sub-micron grains. We provide comprehensive discussion of all the possible grain acceleration mechanisms in interstellar medium. We show that supersonic velocities are attainable for Galactic dust grains. We discuss the consequence of the acceleration. The implications for extinction curve, grain alignment, chemical abundance, etc, are provided.

  18. Study on Fluctuation of Grain Yield in China’s Major Grain Producing Areas

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    By using the statistical data of grain yield in China’s major grain producing areas from 1949 to 2008,and fluctuation theory,the historical process and main cause of fluctuation of grain yield in China’s major grain producing areas are analyzed.The results of research show that the grain yield in China’s major grain producing areas grows in unstable fluctuation,with high-frequency fluctuation cycle and regular length;the amplitude of fluctuation,on the whole,is moderate,with not strong stability;the fluctuation of grain yield has correspondence,reflecting the N-shape developmental trend of grain production at present;the fluctuation of grain yield has gradient characteristics;in the process of comparison of grain yield,the average growth rate annually of grain yield in China’s major grain producing areas is higher than that of the national average,but the relative fluctuation coefficient is also higher than that of the national average.From five aspects,namely natural disaster,agricultural policy,production input,grain price and grain circulation,the cause of fluctuation of grain yield in China’s major grain producing areas is analyzed,and measures of preventing and arresting super-long fluctuation of grain yield are put forward.Firstly,stick to strict farmland protection system,and strive to promote farmland quality;secondly,strengthen infrastructure construction of grain production and beef up the ability of preventing natural disaster;thirdly,quicken the pace of agricultural technology and establish robust technology supporting system;fourthly,lay stress on innovation of agricultural organization system and provide implementation path and vehicle for application of agricultural technology measures;fifthly,perfect disaster precaution system and grain market system,and strengthen the ability of preventing risk of grain production.

  19. Direct imaging of grain boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Gronsky, R.

    1979-09-01

    There are currently two types of microscopes which, in principle, are capable of imaging atom positions at grain boundaries. One, the field ion microscope (FIM), yields a projection of the specimen surface (approximately stereographic) by field ionization of an imaging gas at protruding atom sites, and provides topographic information in high-index pole regions which may be interpreted atom-by-atom. The other, a transmission electron microscope (TEM), yields a projection (approximately linear) of the entire specimen thickness by electron optical imaging, and provides atomic resolution detail throughout the illuminated area. In this paper, both methods are described and compared, using examples from practical materials systems.

  20. More than Rising Grain Prices

    Institute of Scientific and Technical Information of China (English)

    Hu Junhua

    2010-01-01

    @@ According to the bulletin of the National Bureau of Statistics,the summer harvest nationwide this year was 246.2billion jin,a decline of 0.3% compared to last year.The cold spell in late spring and high temperatures afterwards are considered as the main causes for this round of rising grain prices.However,"natural disasters"are dwarfed by another worrisome picture: young and strong farming hands flooding out of the rural areas and the elderly,the weak,females and children are made the mainstay of the tilling army.

  1. High Temperature at Grain-filling Stage Affects Nitrogen Metabolism Enzyme Activities in Grains and Grain Nutritional Quality in Rice

    Institute of Scientific and Technical Information of China (English)

    LIANG Cheng-gang; CHEN Li-ping; WANG Yan; LIU Jia; Xu Guang-li; LI Tian

    2011-01-01

    Rice plants would more frequently suffer from high temperature (HT) stress at the grain-filling stage in future.A japonica rice variety Koshihikari and an indica rice variety IR72 were used to study the effect of high temperature on dynamic changes of glutamine synthetase (GS) activity,glutamate synthase (GOGAT) activity,glutamic oxalo-acetic transminase (GOT) activity,glutamate pyruvate transminase (GPT) activity in grains and grain nutritional quality at the grain-filling stage.Under HT,the activities of GOGAT,GOT,GPT and soluble protein content in grains significantly increased,whereas GS activity significantly decreased at the grain-filling stage.In addition to the increase of protein and amino acids contents,it was suggested that GOGAT,GOT and GPT in grains played important roles in nitrogen metabolism at the grain-filling stage.Since the decrease of GS activity in grains did not influence the accumulations of amino acids and protein,it is implied that GS might not be the key enzyme in regulating glutamine content in grains.

  2. Whole grains and health: from theory to practice--highlights of The Grains for Health Foundation's Whole Grains Summit 2012.

    Science.gov (United States)

    McKeown, Nicola M; Jacques, Paul F; Seal, Chris J; de Vries, Jan; Jonnalagadda, Satya S; Clemens, Roger; Webb, Densie; Murphy, Lee Anne; van Klinken, Jan-Willem; Topping, David; Murray, Robyn; Degeneffe, Dennis; Marquart, Leonard F

    2013-05-01

    The Grains for Health Foundation's Whole Grains Summit, held May 19-22, 2012 in Minneapolis, was the first meeting of its kind to convene >300 scientists, educators, food technologists, grain breeders, food manufacturers, marketers, health professionals, and regulators from around the world. Its goals were to identify potential avenues for collaborative efforts and formulate new approaches to whole-grains research and health communications that support global public health and business. This paper summarizes some of the challenges and opportunities that researchers and nutrition educators face in expanding the knowledge base on whole grains and health and in translating and disseminating that knowledge to consumers. The consensus of the summit was that effective, long-term, public-private partnerships are needed to reach across the globe and galvanize the whole-grains community to collaborate effectively in translating whole-grains science into strategies that increase the availability and affordability of more healthful, grain-based food products. A prerequisite of that is the need to build trust among diverse multidisciplinary professionals involved in the growing, producing, marketing, and regulating of whole-grain products and between the grain and public health communities.

  3. Whole Grains: Hearty Options for a Healthy Diet

    Science.gov (United States)

    ... Lifestyle Nutrition and healthy eating Find out why whole grains are better than refined grains and how to ... your diet. By Mayo Clinic Staff Grains, especially whole grains, are an essential part of a healthy diet. ...

  4. Grain alignment in starless cores

    Energy Technology Data Exchange (ETDEWEB)

    Jones, T. J.; Bagley, M. [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455 (United States); Krejny, M. [Cree Inc., 4600 Silicon Dr., Durham, NC (United States); Andersson, B.-G. [SOFIA Science Center, USRA, Moffett Field, CA (United States); Bastien, P., E-mail: tjj@astro.umn.edu [Centre de recherche en astrophysique du Québec and Départment de Physique, Université de Montréal, Montréal (Canada)

    2015-01-01

    We present near-IR polarimetry data of background stars shining through a selection of starless cores taken in the K band, probing visual extinctions up to A{sub V}∼48. We find that P{sub K}/τ{sub K} continues to decline with increasing A{sub V} with a power law slope of roughly −0.5. Examination of published submillimeter (submm) polarimetry of starless cores suggests that by A{sub V}≳20 the slope for P versus τ becomes ∼−1, indicating no grain alignment at greater optical depths. Combining these two data sets, we find good evidence that, in the absence of a central illuminating source, the dust grains in dense molecular cloud cores with no internal radiation source cease to become aligned with the local magnetic field at optical depths greater than A{sub V}∼20. A simple model relating the alignment efficiency to the optical depth into the cloud reproduces the observations well.

  5. Grain refinement of AZ31 magnesium alloy by electromagnetic stirring under effect of grain-refiner

    Indian Academy of Sciences (India)

    S Y Gao; Q C Le; Z Q Zhang; J Z Cui

    2012-08-01

    The effects of electromagnetic stirring and Al4C3 grain refiner on the grain refinement of semicontinuously cast AZ31 magnesium alloy were discussed in this investigation. The results indicate that electromagnetic stirring has an effective refining effect on the grain size of AZ31 magnesium alloy under the effect of Al4C3 grain refiner. Electromagnetic stirring can `activate’ the Al4C3 particles, resulting in more heterogeneous nucleation sites for the primary -Mg grains. But, longer holding time can `deactivate’ the Al4C3 particles and poison the grain refining effect.

  6. Prediction of HAZ grain size in welding of ultra fine grained steel with different parameters

    Institute of Scientific and Technical Information of China (English)

    Zhao Hongyun; Zhang Hongtao; Li Dongqing; Wang Guodong

    2010-01-01

    The temperature field and thermal cycling curve in the heat-affected zone during welding 400 MPa ultra fine grained steel by plasma arc were simulated using finite element method.The principle of grain growth kinetics was used to predict the grain size in the heat-affected zone under different welding parameters.The simulation results show that the growing tendency of HAZ grain could be controlled by adjusting the welding parameters,but the growth of HAZ grain could not be eliminated at all.The HAZ grain size became small with increasing of the cooling rate and added with increasing of welding current,arc voltage and welding speed.

  7. Quasiclassical Coarse Graining and Thermodynamic Entropy

    CERN Document Server

    Gell-Mann, Murray; Gell-Mann, Murray; Hartle, James

    2006-01-01

    Our everyday descriptions of the universe are highly coarse-grained, following only a tiny fraction of the variables necessary for a perfectly fine-grained description. Coarse graining in classical physics is made natural by our limited powers of observation and computation. But in the modern quantum mechanics of closed systems, some measure of coarse graining is inescapable because there are no non-trivial, probabilistic, fine-grained descriptions. This essay explores the consequences of that fact: Quantum theory allows for various coarse-grained descriptions some of which are mutually incompatible. For most purposes, however, we are interested in the small subset of ``quasiclassical descriptions'' defined by ranges of values of averages over small volumes of densities of conserved quantities such as energy and momentum and approximately conserved quantities such as baryon number. The near-conservation of these quasiclassical quantities results in approximate decoherence, predictability, and local equilibriu...

  8. Determination of grain boundary geometry using TEM

    Energy Technology Data Exchange (ETDEWEB)

    Jang, H.; Farkas, D. (Department of Materials Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0237 (United States)); De Hosson, J.T.M. (Department of Applied Physics, University of Groningen, Nijenborgh 18, 9747 AG, Groningen (Netherlands))

    1992-07-01

    An experimental method to obtain the grain boundary geometry using the transmission electron microscope is presented. The method allows {Sigma} determination including grain boundary plane orientation. In order to determine the specialness of the grain boundary, three different criteria for maximum allowable deviations from exact CSL misorientations were examined. We tested these three criteria from a statistical distribution of grain boundary types in terms of {Sigma}. We compared grain boundary distributions from other studies in Ni{sub 3}Al and found discrepancies among them. It seems that the discrepancy came from the different criteria for special boundaries in {Sigma} determination and different experimental procedures they used. The statistical distribution of grain boundary plane orientations showed that low {Sigma} boundaries ({Sigma}{lt}11) were oriented to the plane of high density of coincident sites.

  9. Grain Boundary Engineering of Electrodeposited Thin Films

    DEFF Research Database (Denmark)

    Alimadadi, Hossein

    of the favorable boundaries that break the network of general grain boundaries. Successful dedicated synthesis of a textured nickel film fulfilling the requirements of grain boundary engineered materials, suggests improved boundary specific properties. However, the textured nickel film shows fairly low......Grain boundary engineering aims for a deliberate manipulation of the grain boundary characteristics to improve the properties of polycrystalline materials. Despite the emergence of some successful industrial applications, the mechanism(s) by which the boundary specific properties can be improved...... is not yet well-understood. This, at least partly, owes to the lack of robust characterization methods for analyzing the nature of grain boundaries including the grain boundary plane characteristics, until recently. In the past decade, significant improvements in the 2-dimensional and 3-dimensional analysis...

  10. Interstellar Extinction by Spheroidal Dust Grains

    OpenAIRE

    Gupta, Ranjan; Mukai, Tadashi; Vaidya, D. B.; Sen, Asoke K.; Okada, Yasuhiko

    2005-01-01

    Observations of interstellar extinction and polarization indicate that the interstellar medium consists of aligned non-spherical dust grains which show variation in the interstellar extinction curve for wavelengths ranging from NIR to UV. To model the extinction and polarization, one cannot use the Mie theory which assumes the grains as solid spheres. We have used a T-matrix based method for computing the extinction efficiencies of spheroidal silicate and graphite grains of different shapes (...

  11. Grain legumes in organic cropping systems

    OpenAIRE

    Hauggaard-Nielsen, Dr. Henrik

    2002-01-01

    Grain legumes are valuable protein and energy sources in animal feeds and in human diets low in meat. Furthermore, grain legumes strongly benefit the cropping system, via biological fixation of atmospheric N2 - a fundamental process for maintaining soil fertility in organic farming systems. Other positive effects in the crop rotations are recycled N-rich crop residues and the break-crop effect in cereals-rich rotations. However, yield variability in grain legumes is well known and related to...

  12. Grain boundaries in silicon solar cells

    Science.gov (United States)

    Kazmerski, L. L.; Russell, P. E.; Ireland, P. J.; Herrington, C. R.; Dick, J. R.; Matson, R. J.; Jones, K. M.

    The correlations between the electrical and compositional properties of grain boundaries in polycrystalline Si are examined in detail. High-resolution surface analysis techniques (AES, SIMS, XPS, EELS) and microelectrical (SAM, EBIC, minority-carrier lifetime) characterization methods are used. The direct evidence for impurity segregation to the intergrain regions is presented. Effect of illumination on the grain boundary electrical characteristics are correlated with impurity compositions. Finally, the interrelationships among heat-treatment, oxygen segregation and grain boundary electrical activity are discussed.

  13. 7 CFR 868.310 - Grades and grade requirements for the classes Long Grain Milled Rice, Medium Grain Milled Rice...

    Science.gov (United States)

    2010-01-01

    ... Grain Milled Rice, Medium Grain Milled Rice, Short Grain Milled Rice, and Mixed Milled Rice. (See also Â... Milled Rice Principles Governing Application of Standards § 868.310 Grades and grade requirements for the classes Long Grain Milled Rice, Medium Grain Milled Rice, Short Grain Milled Rice, and Mixed Milled...

  14. Interactions between grain boundary faceting, migration and grain rotation: Color group and molecular dynamics simulation approaches

    Science.gov (United States)

    Huang, Yue

    Color group theory and molecular dynamics (MD) simulations were used to study the faceting and rotation of grains in nanocrystalline materials and their interactions. Color group arguments were used to determine symmetry-dictated extrema with respect to misorientation of the grains and with respect to grain boundary normal orientations. MD simulations were used to study the evolution of the system and to elucidate the interactions between grain rotation and faceting in nano-scale systems. The systems of study were fcc bicrystalline systems with two grains sharing their [110] directions. Two geometric parameters were studied: the misorientation between two grains with a common rotation axis in the [110] direction of both grains, and the grain boundary normal orientation of fcc (110) tilt grain boundaries. The symmetry-dictated extremum (SDE) with respect to misorientation around both grains' [110] direction is 90 degrees. The SDE with respect to GB normal orientations for (110) tilt GBs are located on top of the color and classical mirror planes of their dichromatic patterns. By using periodic boundary conditions and a cylindrical embedded grain structure in our simulations, grains are only free to vary the misorientation between grains around the common [110] direction, and the normal of the grain boundaries are always perpendicular to both grains [110] direction. All SDE studied in our simulation are observed to be local energy minimum states. We observed the systems reducing their excess energy through three main modes: forming facets at the boundaries, rotating between the two grains, and reduction of grain boundary area through grain shrinkage. Facets are formed in low-energy grain boundaries and oscillating rotation occurred when the initial misorientation was not a SDE. A new algorithm was developed to quantitatively measure the grain rotation. The ovsered rotations are not rigid-body rotations and have strong interaction with faceting. Systems with lower

  15. The Role of Grain Boundary Energy on Grain Boundary Complexion Transitions

    Energy Technology Data Exchange (ETDEWEB)

    Bojarski, Stephanie A. [Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Materials Science and Engineering; Rohrer, Gregory S. [Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Materials Science and Engineering

    2014-09-01

    Grain boundary complexions are distinct equilibrium structures and compositions of a grain boundary and complexion transformations are transition from a metastable to an equilibrium complexion at a specific thermodynamic and geometric conditions. Previous work indicates that, in the case of doped alumina, a complexion transition that increased the mobility of transformed boundaries and resulted in abnormal grain growth also caused a decrease in the mean relative grain boundary energy as well as an increase in the anisotropy of the grain boundary character distribution (GBCD). The current work will investigate the hypothesis that the rates of complexion transitions that result in abnormal grain growth (AGG) depend on grain boundary character and energy. Furthermore, the current work expands upon this understanding and tests the hypothesis that it is possible to control when and where a complexion transition occurs by controlling the local grain boundary energy distribution.

  16. Grain growth and experimental deformation of fine-grained ice aggregates

    Science.gov (United States)

    Diebold, Sabrina; de Bresser, Hans; Spiers, Chris; Durham, William B.; Stern, Laura

    2010-05-01

    Ice is one of the most abundant materials in our solar system. It is the principal constituent of most of the moons of the outer solar system. Thus, the flow behavior of ice is of great interest when studying geodynamic processes on icy moons. Grain growth is an elementary process that is assumed to be important in the ice sheet layering of planetary moons, where temperatures 100-273 K exist. We concentrate on the questions to what extent grain growth may influence the evolution of strength of deforming ice and if the grain growth process is independent or dependent of deformation. The answers to these questions will help us to quantitatively test the hypothesis that the progressive evolution of the grain (crystal) size distribution of deforming and recrystallizing ice directly affects its rheological behaviour in terms of composite grain-size-sensitive (GSS) and grain-size-insensitive (GSI) creep, and that this might, after time, result in a steady state balance between mechanisms of GSS and GSI creep. We performed static grain growth experiments at different temperatures and a pressure (P) of 1 atm, and deformation experiments at P = 30-100 MPa starting in the GSS-creep field. The starting material ice Ih has a grain size growth tests a Hart Scientific temperature bath was filled with d-Limonene as cooling medium. The ice specimens were put into sealed alumina cylinders. For the grain growth tests, temperatures (T) between 213 K and 268 K were chosen. The durations of these tests varied between one day and two weeks. For the deformation experiments, temperatures of > 170 K and strain rates between 10-8 s-1 and 10-4 s-1 were chosen. Grain sizes, grain size distributions and grain topologies were measured by cryogenic SEM and image analysis techniques. We found clear evidence of grain growth and a significantly T-dependent variation of grain size distributions. The observations allow us to calibrate values for the grain size exponent n and the activation energy Q

  17. Grain boundary corrosion of copper canister material

    Energy Technology Data Exchange (ETDEWEB)

    Fennell, P.A.H.; Graham, A.J.; Smart, N.R.; Sofield, C.J. [AEA Technology plc, Harwell (United Kingdom)

    2001-03-01

    The proposed design for a final repository for spent fuel and other long-lived residues in Sweden is based on the multi-barrier principle. The waste will be encapsulated in sealed cylindrical canisters, which will then be placed in granite bedrock and surrounded by compacted bentonite clay. The canister design is based on a thick cast inner container fitted inside a corrosion-resistant copper canister. During fabrication of the outer copper canisters there will be some unavoidable grain growth in the welded areas. As grains grow they will tend to concentrate impurities within the copper at the new grain boundaries. The work described in this report was undertaken to determine whether there is any possibility of enhanced corrosion at grain boundaries within the copper canister. The potential for grain boundary corrosion was investigated by exposing copper specimens, which had undergone different heat treatments and hence had different grain sizes, to aerated artificial bentonite-equilibrated groundwater with two concentrations of chloride, for increasing periods of time. The degree of grain boundary corrosion was determined by atomic force microscopy (AFM) and optical microscopy. AFM showed no increase in grain boundary 'ditching' for low chloride groundwater. In high chloride groundwater the surface was covered uniformly with a fine-grained oxide. No increases in oxide thickness were observed. No significant grain boundary attack was observed using optical microscopy either. The work suggests that in aerated artificial groundwaters containing chloride ions, grain boundary corrosion of copper is unlikely to adversely affect SKB's copper canisters.

  18. Grain Unloading of Arsenic Species in Rice

    Energy Technology Data Exchange (ETDEWEB)

    Carey, Anne-Marie; Scheckel, Kirk G.; Lombi, Enzo; Newville, Matt; Choi, Yongseong; Norton, Gareth J.; Charnock, John M.; Feldmann, Joerg; Price, Adam H.; Meharg, Andrew A. (EPA); (U. South Australia); (Manchester); (Aberdeen); (UC)

    2010-01-11

    Rice (Oryza sativa) is the staple food for over half the world's population yet may represent a significant dietary source of inorganic arsenic (As), a nonthreshold, class 1 human carcinogen. Rice grain As is dominated by the inorganic species, and the organic species dimethylarsinic acid (DMA). To investigate how As species are unloaded into grain rice, panicles were excised during grain filling and hydroponically pulsed with arsenite, arsenate, glutathione-complexed As, or DMA. Total As concentrations in flag leaf, grain, and husk, were quantified by inductively coupled plasma mass spectroscopy and As speciation in the fresh grain was determined by x-ray absorption near-edge spectroscopy. The roles of phloem and xylem transport were investigated by applying a {+-} stem-girdling treatment to a second set of panicles, limiting phloem transport to the grain in panicles pulsed with arsenite or DMA. The results demonstrate that DMA is translocated to the rice grain with over an order magnitude greater efficiency than inorganic species and is more mobile than arsenite in both the phloem and the xylem. Phloem transport accounted for 90% of arsenite, and 55% of DMA, transport to the grain. Synchrotron x-ray fluorescence mapping and fluorescence microtomography revealed marked differences in the pattern of As unloading into the grain between DMA and arsenite-challenged grain. Arsenite was retained in the ovular vascular trace and DMA dispersed throughout the external grain parts and into the endosperm. This study also demonstrates that DMA speciation is altered in planta, potentially through complexation with thiols.

  19. Superior grains determined by grain weight are not fully correlated with the lfowering order in rice

    Institute of Scientific and Technical Information of China (English)

    PENG Ting; ZHAO Quan-zhi; L Qiang; ZHAO Ya-fan; SUN Hong-zheng; HAN Ying-chun; DU Yan-xiu; ZHANG Jing; LI Jun-zhou; WANG Lin-lin

    2015-01-01

    Rice panicles are composed of many branches with two types of extreme grains, the superior and the inferior. Traditional y, it has been wel accepted that earlier lfowers result in superior grains and late lfowers generate inferior grains. However, these correlations have never been strictly examined in practice. In order to determine the accurate relationship between superior and inferior grains and the lfowering order, we localized al the seeds in a panicle in four distinct rice species and systematical y documented the rice lfowering order, lfower locations and the ifnal grain weight for their relationships. Our results demonstrated that the grain weight is more heavily determined by the position of the seeds than by the lfowering order. Despite earlier lfowering has a positive correlation with the grain weight in general, grains from lfowers blooming on the second day after anthesis general y gained the highest weight. This suggests earlier lfowers may not result in superior grains. Therefore, we concluded that superior and inferior grains, commonly determined by grain weight, are not ful y cor-related with the lfowering order in rice. Fol owing the order of the grain weight, the superior grains are general y localized at the middle parts of the primary branches, whereas inferior grains were mainly on the last two secondary branches of the lower half part of the panicle. In addition, the weight of inferior grains were affected by spikelet thinning and spraying with exogenous plant growth regulators, indicating that physiological incompetence might be the major reason for the occurrence of the inferior grains.

  20. Plagioclase-Rich Itokawa Grains: Space Weathering, Exposure Ages, and Comparison to Lunar Soil Grains

    Science.gov (United States)

    Keller, L. P.; Berge, E.

    2017-01-01

    Regolith grains returned by the Hayabusa mission to asteroid 25143 Itokawa provide the only samples currently available to study the interaction of chondritic asteroidal material with the space weathering environment. Several studies have documented the surface alterations observed on the regolith grains, but most of these studies involved olivine because of its abundance. Here we focus on the rarer Itokawa plagioclase grains, in order to allow comparisons between Itokawa and lunar soil plagioclase grains for which an extensive data set exists.

  1. Irradiation-induced grain growth and defect evolution in nanocrystalline zirconia with doped grain boundaries.

    Science.gov (United States)

    Dey, Sanchita; Mardinly, John; Wang, Yongqiang; Valdez, James A; Holesinger, Terry G; Uberuaga, Blas P; Ditto, Jeff J; Drazin, John W; Castro, Ricardo H R

    2016-06-22

    Grain boundaries are effective sinks for radiation-induced defects, ultimately impacting the radiation tolerance of nanocrystalline materials (dense materials with nanosized grains) against net defect accumulation. However, irradiation-induced grain growth leads to grain boundary area decrease, shortening potential benefits of nanostructures. A possible approach to mitigate this is the introduction of dopants to target a decrease in grain boundary mobility or a reduction in grain boundary energy to eliminate driving forces for grain growth (using similar strategies as to control thermal growth). Here we tested this concept in nanocrystalline zirconia doped with lanthanum. Although the dopant is observed to segregate to the grain boundaries, causing grain boundary energy decrease and promoting dragging forces for thermally activated boundary movement, irradiation induced grain growth could not be avoided under heavy ion irradiation, suggesting a different growth mechanism as compared to thermal growth. Furthermore, it is apparent that reducing the grain boundary energy reduced the effectiveness of the grain boundary as sinks, and the number of defects in the doped material is higher than in undoped (La-free) YSZ.

  2. Stabilisation of the grain market by the flexible use of grain for bioethanol

    NARCIS (Netherlands)

    Helming, J.F.M.; Pronk, A.; Woltjer, I.

    2010-01-01

    This report reviews whether the grain market and grain price can be stabilised by the variation of the use of grain in the EU-27's production of bioethanol. The time horizon of this study is 2020, whereby account is taken of the minimum 10% obligation for biofuel use in the EU-27. An economic comput

  3. Linear grain growth kinetics and rotation in nanocrystalline Ni

    OpenAIRE

    Farkas, Diana; Mohanty, S.; Monk, J.

    2007-01-01

    We report three-dimensional atomistic molecular dynamics studies of grain growth kinetics in nanocrystalline Ni. The results show the grain size increasing linearly with time, contrary to the square root of the time kinetics observed in coarse-grained structures. The average grain boundary energy per unit area decreases simultaneously with the decrease in total grain boundary area associated with grain growth. The average mobility of the boundaries increases as the grain size increases. The r...

  4. Reducing grain storage losses in developing countries

    Science.gov (United States)

    We investigated the use of insecticide-treated material and modified atmosphere storage for reducing insect damage in stored maize. Results showed that insecticide treated netting and insecticide treated seed bags protected grain from insect damage for up to nine months if the grain was free from i...

  5. SEGMENTATION AND GRAIN SIZE OF CERAMICS

    Directory of Open Access Journals (Sweden)

    Xavier Arnould

    2011-05-01

    Full Text Available This paper presents some methods to automatically extract the grain boundaries of materials in order to develop an automatic method to determine the grain size and morphological parameters of ceramic materials. Results are presented in the case of sintered cerine (CeO2 materials.

  6. Grain transport mechanics in shallow overland flow

    Science.gov (United States)

    A physical model based on continuum multiphase flow is described to represent saltating transport of grains in shallow overland flow. The two phase continuum flow of water and sediment considers coupled St.Venant type equations. The interactive cumulative effect of grains is incorporated by a disper...

  7. Grain transport mechanics in shallow flow

    Science.gov (United States)

    A physical model based on continuum multiphase flow is described to represent saltating transport of grains in shallow overland flows. The two-phase continuum flow of water and sediment considers coupled St.Venant type equations. The interactive cumulative effect of grains is incorporated by a dispe...

  8. Insect Population Dynamics in Commercial Grain Elevators

    Science.gov (United States)

    Data were collected in 1998-2002 from wheat stored in commercial grain elevators in south-central Kansas. Storage bins at these elevators had concrete walls and were typically 6-9 m in diameter and 30-35 m tall. A vacuum-probe sampler was used to collect ten 3-kg grain samples in the top 12 m of the...

  9. Temperature fluctuations of interstellar dust grains

    CERN Document Server

    Horn, Kobi; Biham, Ofer

    2007-01-01

    The temperatures of interstellar dust grains are analyzed using stochastic simulations, taking into account the grain composition and size and the discreteness of the photon flux. [...] The distribution of grain temperatures is calculated for a broad range of grain sizes and for different intensities of the interstellar radiation field, relevant to diffuse clouds and to PDRs. The dependence of the average grain temperature on its size is shown for different irradiation intensities. It is found that the average temperatures of grains with radii smaller than about 0.02 $\\mu$m are reduced due to the fluctuations. The average temperatures of grains of radii larger than about 0.35 $\\mu$m are also slightly reduced due to their more efficient emission of infrared radiation, particularly when exposed to high irradiation intensities. The average temperatures of silicate and carbonaceous grains are found to depend on the radiation field intensity X_MMP according to ~X_MMP^gamma, where the exponent gamma depends on the...

  10. Topological Transformation during Normal Grain Growth

    Institute of Scientific and Technical Information of China (English)

    Chaogang LOU; Michael A.Player

    2004-01-01

    This paper investigates topological transformation during normal grain growth by carrying out a computer vertex simulation.Results show that topological correlation agrees with the models proposed by Blanc et al. and Weaire. Topological transformation occurs more often on grains with some topological classes instead of equal probability on each boundary. This can be qualitatively explained by topological correlation.

  11. Grain boundaries in high-Tc superconductors

    NARCIS (Netherlands)

    Hilgenkamp, H.; Mannhart, J.

    2002-01-01

    Since the first days of high-Tc superconductivity, the materials science and the physics of grain boundaries in superconducting compounds have developed into fascinating fields of research. Unique electronic properties, different from those of the grain boundaries in conventional metallic supercondu

  12. Constraining the Porosities of Interstellar Dust Grains

    CERN Document Server

    Heng, Kevin

    2009-01-01

    We present theoretical calculations of the X-ray scattering properties of porous grain aggregates with olivine monomers. The small and large angle scattering properties of these aggregates are governed by the global structure and substructure of the grain, respectively. We construct two diagnostics, R_X and T_X, based on the optical and X-ray properties of the aggregates, and apply them to a Chandra measurement of the dust halo around the Galactic binary GX13+1. Grain aggregates with porosities higher than about 0.55 are ruled out. Future high-precision observations of X-ray dust haloes together with detailed modeling of the X-ray scattering properties of porous grain mixtures will further constrain the presence of porous grain aggregates in a given dust population.

  13. Refinement and stability of grain structure

    Energy Technology Data Exchange (ETDEWEB)

    John Humphreys, F.; Bate, P.S. [Manchester Univ. (United Kingdom). Manchester Materials Science Centre

    2001-07-01

    The various methods of producing fine-grained alloys are discussed and it is concluded that thermomechanical processing routes are most suitable for the economic production of the large quantities of material required for structural applications. The limits of grain refinement by conventional discontinuous recrystallization are considered, and the production of micron-grained alloys by continuous recrystallization processes during or after large strain deformation is discussed. The stability of highly deformed microstructures against recrystallization is analysed, and the effect of second-phase particles on grain growth is discussed. It is shown that perturbations of the Zener drag during high temperature deformation may lead to dynamic grain growth in two-phase alloys. (orig.)

  14. Coarse graining of polystyrene sulfonate

    Science.gov (United States)

    Perahia, Dvora; Agrawal, Anupriya; Grest, Gary S.

    2015-03-01

    Capturing large length scales in soft matter while retaining atomistic properties is imperative to computational studies. Here we develop a new coarse-grained model for polystyrene sulfonate (PSS) that often serves as a model system because of its narrow molecular weight distribution and defined degree of sulfonation. Four beads are used to represent polymer where the backbone, the phenyl group, and the sulfonated group are each represented by a different bead and the fourth one represents counterion, which is sodium in our case. Initial atomistic simulations of PSS melt with sulfonation levels of 2-10%, with a dielectric constant ɛ = 1 revealed a ``locked'' phase where motion of the polymer is limited. Dielectric constant of ɛ = 5 was used to accelerate the dynamics. Bonded interactions were obtained using Boltzmann inversion on the bonded distributions extracted from atomistic simulation. Non-bonded interaction of polystyrene monomer was taken from our previous work and potential of mean force was used as the initial guess for interaction of the ionic beads. This set of potential was subsequently iterated to get a good match with radial distribution functions. This potential and its transferability across dielectric constants and temperatures will be presented. Grant DE-SC007908.

  15. Entropy production in coarse grained Vlasov equations

    Energy Technology Data Exchange (ETDEWEB)

    Morawetz, K. [Grand Accelerateur National d' Ions Lourds (GANIL), LPC-ISMRA, 14 - Caen (France); Walke, R. [Rostock Univ., Fachbereich Physick (Germany)

    2000-07-01

    The Vlasov equation is analyzed for coarse grained distributions. This coarse graining resembles a finite width of test-particles as used in numerical implementations. It is shown that this coarse grained distribution obeys a kinetic equation similar to the Vlasov equation, but with additional terms. These terms give rise to entropy production indicating dissipative features. The reason is a nonlinear mode coupling due to the finite width of the test-particles. The interchange of coarse graining and dynamical evolution is discussed with the help of an exactly solvable model and practical consequences are worked out. By calculating analytically the stationary solution we can show that a sum of modified Boltzmann-like distributions is approached dependent on the initial distribution. This behavior is independent of degeneracy and only controlled by the width of test-particles. The condition for approaching a stationary solution is derived in that the coarse graining energy given by momentum coarse graining should be smaller than a quarter of the kinetic energy. Observable consequences of this coarse graining are: (i) In the thermodynamics the coarse graining leads to spatial correlations in observables. (ii) Too large radii of nucleus in self-consistent treatments are observed and an explicit correction term appears in the Thomas Fermi equation. (iii) The momentum coarse graining translates into a structure term in the response function and resembles to a certain extent vertex correction correlations or internal structure effects. (iv) The coarse graining which is numerically unavoidable leads to a modified centroid energy and higher damping width of collective modes. The numerical codes should be revised in that a refolding is proposed. (author)

  16. ISOCHRONS IN PRESOLAR GRAPHITE GRAINS FROM ORGUEIL

    Energy Technology Data Exchange (ETDEWEB)

    Zinner, Ernst; Jadhav, Manavi, E-mail: ekz@wustl.edu [Laboratory for Space Sciences and the Physics Department, Washington University, One Brookings Drive, St. Louis, MO 63130 (United States)

    2013-05-10

    Primitive meteorites contain tiny dust grains that condensed in stellar outflows and explosions. These stardust grains can be extracted from their host meteorites and studied in detail in the laboratory. We investigated depth profiles of the Al-Mg, Ca-K, and Ti-Ca isotopic systems obtained during NanoSIMS isotopic analysis of presolar graphite grains from the CI carbonaceous meteorite Orgueil. Large {sup 26}Al/{sup 27}Al, {sup 41}Ca/{sup 40}Ca, and {sup 44}Ti/{sup 48}Ti ratios, inferred from {sup 26}Mg, {sup 41}K, and {sup 44}Ca excesses from the decay of the short-lived radioisotopes {sup 26}Al, {sup 41}Ca, and {sup 44}Ti, indicate a supernova (SN) origin. From the depth distribution of the radiogenic isotopes and the stable isotopes of their parent elements we constructed isochron-type correlation plots. The plots indicate quantitative retention of radiogenic {sup 26}Mg, {sup 41}K, and {sup 44}Ca in most grains. Deviations from straight lines in the Al-Mg and Ca-K plots can be explained by contamination with {sup 27}Al and isotopically normal Ca, respectively. For the Ti-Ca system in some grains, the lack of parent-daughter correlation indicates either redistribution of radiogenic {sup 44}Ca or heterogeneity in the initial {sup 44}Ti/{sup 48}Ti ratio. We also obtained Si isotopic depth profiles in three graphite grains with large {sup 29}Si and {sup 30}Si excesses, for which a SN origin has been proposed. In two grains no Si-rich subgrains are observed; in the third grain with an apparent Si-rich subgrain the anomalous Si isotopic ratios in the subgrain are the same as in the rest of the graphite host. Our studies show that by measuring depth profiles, information on presolar grains can be obtained that cannot be obtained by whole-grain analysis.

  17. Influence of China’s Grain Industrial Market Structure over Grain Pricing Power

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    From the point of view of industrial market structure,we analyze the influence of market structure on grain production,circulation,and processing,and on the grain pricing power of entities along China’s grain industrial chain.Through analysis,it is indicated that different features of market structure play a significant role in pricing power of such microeconomic entities as farmers and grain enterprises in grain production and transaction.And the market structure determines welfare distribution model of consumers’ surplus and producers’ surplus at the market.

  18. Short Communication. Effect of phosphorus nutrition and grain position within maize cob on grain phosphorus accumulation

    Directory of Open Access Journals (Sweden)

    Muhamamad Nadeem

    2014-04-01

    Full Text Available Nutritional status of grains may vary due to external nutrient supply and their position within parent maize cob. Phosphorus (P is the least mobile nutrient in the soil and therefore newly growing seedlings are largely dependent on the stored grain P contents which are accumulated during the crop maturity period. Objective of this study was to access the effects of different P applications and grain positions on P and dry matter contents in grains. Phosphorus application and grain position has significant (p<0.05 effects on P contents in grains whereas dry weight and P content are highly correlated. Grain weight and P contents decreased linearly from base to apical position possibly due to flow of nutrients from base towards apical position within cob. Significantly higher grain dry weight (0.35±0.01 g and P contents (962±57 µg P are recorded in high P application (92.50 kg ha-1 rate on base position whereas minimum grain dry weight (0.14±0.01 g and P contents (219±11 µg P were recorded on apical grain position in low P application (5.60 kg ha-1 rate. The results suggest that for better seedling P nutrition especially in soils of low inherent P, maize grains should be selected from base or middle position where maximum dry weight and P contents are concentrated to support the seedlings to reach at growth at which roots are capable of external P uptake.

  19. A constitutive model of nanocrystalline metals based on competing grain boundary and grain interior deformation mechanisms

    KAUST Repository

    Gurses, Ercan

    2011-12-01

    In this work, a viscoplastic constitutive model for nanocrystalline metals is presented. The model is based on competing grain boundary and grain interior deformation mechanisms. In particular, inelastic deformations caused by grain boundary diffusion, grain boundary sliding and dislocation activities are considered. Effects of pressure on the grain boundary diffusion and sliding mechanisms are taken into account. Furthermore, the influence of grain size distribution on macroscopic response is studied. The model is shown to capture the fundamental mechanical characteristics of nanocrystalline metals. These include grain size dependence of the strength, i.e., both the traditional and the inverse Hall-Petch effects, the tension-compression asymmetry and the enhanced rate sensitivity. © 2011 Elsevier B.V. All rights reserved.

  20. AC susceptibility studies of grain-aligned superconductors by grained Bean model

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Nobuyoshi; Akune, Tadahiro [Department of Electrical Engineering and Information Technology, Kyushu Sangyo University, 2-3-1 Matsukadai, Fukuoka (Japan); Matsumoto, Yasukuni, E-mail: saka@te.kyusan-u.ac.j [Department of Electrical Engineering, Fukuoka University, 8-19-1 Nanakuma Fukuoka (Japan)

    2009-03-01

    AC susceptibility of low-T{sub c} metallic superconductors shows smooth transition in the in-phase chi' and a peak in the out-phase chi''. High-T{sub c} oxide superconductors with anisotropic and grain-textured structures show deformed complex characteristics, such as double peaks in chi'' and shoulders in chi'. Instead of simple Bean model, a grained Bean model, where the superconducting grains is immersed in weak superconducting matrix, are proposed. The susceptibilities numerically analyzed using the grained Bean model show varied and deformed curves as observed in the high-T{sub c} superconductors. From the dependence of chi' and chi'' on temperatures T and DC magnetic fields B{sub dc} in grain-aligned Hg(Re)-1223 superconductors, textures of grains and interconnecting links and their grain-aligned nature can be estimated.

  1. AC susceptibility studies of grain-aligned superconductors by grained Bean model

    Science.gov (United States)

    Sakamoto, Nobuyoshi; Akune, Tadahiro; Matsumoto, Yasukuni

    2009-03-01

    AC susceptibility of low-Tc metallic superconductors shows smooth transition in the in-phase χ' and a peak in the out-phase χ". High-Tc oxide superconductors with anisotropic and grain-textured structures show deformed complex characteristics, such as double peaks in χ" and shoulders in χ'. Instead of simple Bean model, a grained Bean model, where the superconducting grains is immersed in weak superconducting matrix, are proposed. The susceptibilities numerically analyzed using the grained Bean model show varied and deformed curves as observed in the high-Tc superconductors. From the dependence of χ' and χ" on temperatures T and DC magnetic fields Bdc in grain-aligned Hg(Re)-1223 superconductors, textures of grains and interconnecting links and their grain-aligned nature can be estimated.

  2. Densification and grain coarsening of melting snow

    Institute of Scientific and Technical Information of China (English)

    周石硚; 中尾正义; 桥本重将; 坂井亚规子; 成田英器; 石川信敬

    2003-01-01

    A field work was conducted at Moshiri in Japan.The work included intensive snow pit work, taking snow grain photos, recording snow and air temperatures, as well as measuring snow water content.By treating the snow as a viscous fluid, it is found that the snow compactive viscosity decreases as the density increases, which is opposite to the relation for dry snow.Based on the measurements of snow grain size, it is shown that, similar to the water-saturated snow, the frequency distributions of grain size at different times almost have the same shape.This reveals that the water-unsaturated melting snow holds the same grain-coarsening behavior as the water-saturated snow does.It is also shown that the water-unsaturated melting snow coarsens much more slowly than the water-saturated snow.The C value, which is the viscosity when the snow density is zero, is related to the mean grain size and found to decrease with increasing grain size.The decreasing rate of C value increases with decreasing grain-coarsening rate.

  3. Spatial correlation in grain misorientation distribution

    Energy Technology Data Exchange (ETDEWEB)

    Beausir, Benoit, E-mail: benoit.beausir@univ-metz.fr [Laboratoire de Physique et Mecanique des Materiaux, Universite Paul Verlaine - Metz/CNRS, Ile du Saulcy, 57045 Metz (France)] [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Fressengeas, Claude [Laboratoire de Physique et Mecanique des Materiaux, Universite Paul Verlaine - Metz/CNRS, Ile du Saulcy, 57045 Metz (France); Gurao, Nilesh P. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Toth, Laszlo S. [Laboratoire de Physique et Mecanique des Materiaux, Universite Paul Verlaine - Metz/CNRS, Ile du Saulcy, 57045 Metz (France); Suwas, Satyam [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India)

    2009-10-15

    Grain misorientation was studied in relation to the nearest neighbor's mutual distance using electron back-scattered diffraction measurements. The misorientation correlation function was defined as the probability density for the occurrence of a certain misorientation between pairs of grains separated by a certain distance. Scale-invariant spatial correlation between neighbor grains was manifested by a power law dependence of the preferred misorientation vs. inter-granular distance in various materials after diverse strain paths. The obtained negative scaling exponents were in the range of -2 {+-} 0.3 for high-angle grain boundaries. The exponent decreased in the presence of low-angle grain boundaries or dynamic recrystallization, indicating faster decay of correlations. The correlations vanished in annealed materials. The results were interpreted in terms of lattice incompatibility and continuity conditions at the interface between neighboring grains. Grain-size effects on texture development, as well as the implications of such spatial correlations on texture modeling, were discussed.

  4. Interstellar Grains: Effect of Inclusions on Extinction

    CERN Document Server

    Katyal, Nisha; Vaidya, D B

    2011-01-01

    A composite dust grain model which simultaneously explains the observed interstellar extinction, polarization, IR emission and the abundance constraints, is required. We present a composite grain model, which is made up of a host silicate oblate spheroid and graphite inclusions. The interstellar extinction curve is evaluated in the spectral region 3.4-0.1$\\mu m$ using the extinction efficiencies of the composite spheroidal grains for three axial ratios. Extinction curves are computed using the discrete dipole approximation (DDA). The model curves are subsequently compared with the average observed interstellar extinction curve and with an extinction curve derived from the IUE catalogue data.

  5. Interstellar grains: Effect of inclusions on extinction

    Science.gov (United States)

    Katyal, N.; Gupta, R.; Vaidya, D. B.

    2011-10-01

    A composite dust grain model which simultaneously explains the observed interstellar extinction, polarization, IR emission and the abundance constraints, is required. We present a composite grain model, which is made up of a host silicate oblate spheroid and graphite inclusions. The interstellar extinction curve is evaluated in the spectral region 3.4-0.1 μm using the extinction efficiencies of composite spheroidal grains for three axial ratios. Extinction curves are computed using the discrete dipole approximation (DDA). The model curves are subsequently compared with the average observed interstellar extinction curve and with an extinction curve derived from the IUE catalogue data.

  6. CASS Ferrite and Grain Structure Relationship

    Energy Technology Data Exchange (ETDEWEB)

    Ruud, Clayton O. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ramuhalli, Pradeep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Meyer, Ryan M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Diaz, Aaron A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Anderson, Michael T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-07-13

    This document summarizes the results of research conducted at Pacific Northwest National Laboratory (PNNL) to determine whether, based on experimental measurements, a correlation existed between grain structure in cast austenitic stainless steel (CASS) piping and ferrite content of the casting alloy. The motivation for this research lies in the fact that ultrasonic testing (UT) is strongly influenced by CASS grain structure; knowledge of this grain structure may help improve the ability to interpret UT responses, thereby improving the overall reliability of UT inspections of CASS components.

  7. RF installation for the grain disinfestation

    CERN Document Server

    Zajtzev, B V; Kobetz, A F; Rudiak, B I

    2001-01-01

    The ecologically pure method of grain product disinfestations through the grain treatment with the RF electric field is described. The experimental data obtained showed that with strengths of the electrical RF field of E=5 kV/cm and frequency of 80 MHz the relative death rate is 100%.The time of the grain treatment it this case is 1 sec. The pulses with a duration of 600 mu s and repetition rate of 2 Hz were used, the duration of the front was 10 mu s. The schematic layout of installation with a productivity of 50 tones/h and power of 10 kW is given.

  8. Parsing abnormal grain growth in specialty aluminas

    Science.gov (United States)

    Lawrence, Abigail Kremer

    Grain growth in alumina is strongly affected by the impurities present in the material. Certain impurity elements are known to have characteristic effects on abnormal grain growth in alumina. Specialty alumina powders contain multiple impurity species including MgO, CaO, SiO2, and Na 2O. In this work, sintered samples made from alumina powders containing various amounts of the impurities in question were characterized by their grain size and aspect ratio distributions. Multiple quantitative methods were used to characterize and classify samples with varying microstructures. The grain size distributions were used to partition the grain size population into subpopulations depending on the observed deviation from normal behavior. Using both grain size and aspect ratio a new visual representation for a microstructure was introduced called a morphology frequency map that gives a fingerprint for the material. The number of subpopulations within a sample and the shape of the distribution on the morphology map provided the basis for a classification scheme for different types of microstructures. Also using the two parameters a series of five metrics were calculated that describe the character of the abnormal grains in the sample, these were called abnormal character values. The abnormal character values describe the fraction of grains that are considered abnormal, the average magnitude of abnormality (including both grain size and aspect ratio), the average size, and variance in size. The final metric is the correlation between grain size and aspect ratio for the entire population of grains. The abnormal character values give a sense of how different from "normal" the sample is, given the assumption that a normal sample has a lognormal distribution of grain size and a Gaussian distribution of aspect ratios. In the second part of the work the quantified measures of abnormality were correlated with processing parameters such as composition and heat treatment conditions. A

  9. Hard-core thinnings of germ-grain models with power-law grain sizes

    CERN Document Server

    Kuronen, Mikko

    2012-01-01

    Random sets with long-range dependence can be generated using a Boolean model with power-law grain sizes. We study thinnings of such Boolean models which have the hard-core property that no grains overlap in the resulting germ-grain model. A fundamental question is whether long-range dependence is preserved under such thinnings. To answer this question we study four natural thinnings of a Poisson germ-grain model where the grains are spheres with a regularly varying size distribution. We show that a thinning which favors large grains preserves the slow correlation decay of the original model, whereas a thinning which favors small grains does not. Our most interesting finding concerns the case where only disjoint grains are retained, which corresponds to the well-known Mat\\'ern type I thinning. In the resulting germ-grain model, typical grains have exponentially small sizes, but rather surprisingly, the long-range dependence property is still present. As a byproduct, we obtain new mechanisms for generating hom...

  10. In vitro binding of Sorghum bicolor transcription factors ABI4 and ABI5 to a conserved region of a GA 2-OXIDASE promoter: possible role of this interaction in the expression of seed dormancy.

    Science.gov (United States)

    Cantoro, Renata; Crocco, Carlos Daniel; Benech-Arnold, Roberto Luis; Rodríguez, María Verónica

    2013-12-01

    The precise adjustment of the timing of dormancy release according to final grain usage is still a challenge for many cereal crops. Grain sorghum [Sorghum bicolor (L.) Moench] shows wide intraspecific variability in dormancy level and susceptibility to pre-harvest sprouting (PHS). Both embryo sensitivity to abscisic acid (ABA) and gibberellin (GA) metabolism play an important role in the expression of dormancy of the developing sorghum grain. In previous works, it was shown that, simultaneously with a greater embryo sensitivity to ABA and higher expression of SbABA-INSENSITIVE 4 (SbABI4) and SbABA-INSENSITIVE 5 (SbABI5), dormant grains accumulate less active GA4 due to a more active GA catabolism. In this work, it is demonstrated that the ABA signalling components SbABI4 and SbABI5 interact in vitro with a fragment of the SbGA 2-OXIDASE 3 (SbGA2ox3) promoter containing an ABA-responsive complex (ABRC). Both transcription factors were able to bind the promoter, although not simultaneously, suggesting that they might compete for the same cis-acting regulatory sequences. A biological role for these interactions in the expression of dormancy of sorghum grains is proposed: either SbABI4 and/or SbABI5 activate transcription of the SbGA2ox3 gene in vivo and promote SbGA2ox3 protein accumulation; this would result in active degradation of GA4, thus preventing germination of dormant grains. A comparative analysis of the 5'-regulatory region of GA2oxs from both monocots and dicots is also presented; conservation of the ABRC in closely related GA2oxs from Brachypodium distachyon and rice suggest that these species might share the same regulatory mechanism as proposed for grain sorghum.

  11. Grains storage using a field technique

    Directory of Open Access Journals (Sweden)

    Gourgue, H.

    1987-01-01

    Full Text Available Maize or other grains can be protected from insects during storage by filling empty drums, and adding a few handfuls of dry laterite soil. The tap is then rescrewed. The drum is ready for storage.

  12. The NGDC Seafloor Sediment Grain Size Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NGDC (now NCEI) Seafloor Sediment Grain Size Database contains particle size data for over 17,000 seafloor samples worldwide. The file was begun by NGDC in 1976...

  13. Scale effect and geometric shapes of grains

    Institute of Scientific and Technical Information of China (English)

    GUO Hui; GUO Xing-ming

    2007-01-01

    The rule-of-mixture approach has become one of the widely spread ways to investigate the mechanical properties of nano-materials and nano-structures, and it is very important for the simulation results to exactly compute phase volume fractions. The nanocrystalline (NC) materials are treated as three-phase composites consisting of grain core phase, grain boundary (GB) phase and triple junction phase, and a two-dimensional three-phase mixture regular polygon model is established to investigate the scale effect of mechanical properties of NC materials due to the geometrical polyhedron characteristics of crystal grain. For different multi-sided geometrical shapes of grains, the corresponding regular polygon model is adopted to obtain more precise phase volume fractions and exactly predict the mechanical properties of NC materials.

  14. Grain operator miffed at port administration

    Index Scriptorium Estoniae

    2006-01-01

    Ventspils Grain Terminal saatis president Vaira Vike-Freibergale ja mitmetele ministritele kirja sõnumiga, et Ventspilsi Vabasadama (Ventspils Free Port) administratsiooni tegevus takistab terminali äritegevust

  15. Thermomagnetic Stability in Pseudo Single Domain Grains

    Science.gov (United States)

    Nagy, Lesleis; Williams, Wyn; Muxworthy, Adrian; Fabian, Karl; Conbhuí, Pádraig Ó.

    2016-04-01

    The reliability of paleomagnetic remanences are well understood for fine grains of magnetite that are single-domain (SD, uniformly magnetized). In particular Néel's theory [1] outlined the thermal energies required to block and unblock magnetic remanences. This lead to determination of thermal stability for magnetization in fine grains as outlined in Pullaiah et. al. [2] and a comprehensive understanding of SD paleomagnetic recordings. It has been known for some time that single domain magnetite is possible only in the grain size range 30 - 80nm, which may only account for a small fraction of the grain size distribution in any rock sample. Indeed rocks are often dominated by grains in the pseudo single domain (PSD) size range, at approximately 80 - 1000nm. Toward the top end of this range multi-domain features begin to dominate. In order to determine thermomagnetic stability in PSD grains we need to identify the energy barriers between all possible pairs of local energy minima (LEM) domain states as a function of both temperature and grain size. We have attempted to do this using the nudged elastic band (NEB) method [3] which searches for minimum energy paths between any given pair of LEM states. Using this technique we have determined, for the first time, complete thermomagnetic stability curves for PSD magnetite. The work presented is at a preliminary stage. However it can be shown that PSD grains of magnetite with simple geometries (e.g. cubes or cuboctahedra) have very few low energy transition paths and the stability is likely to be similar to that observed for SD grains (as expected form experimental observations). The results will provide a basis for a much more rigorous understanding of the fidelity of paleomagnetic signals in assemblages of PSD grains and their ability to retain ancient recordings of the geomagnetic field. References: [1] Néel, Louis. "Théorie du traînage magnétique des ferromagnétiques en grains fins avec applications aux terres

  16. Lifetime grain consumption and breast cancer risk.

    Science.gov (United States)

    Farvid, Maryam S; Cho, Eunyoung; Eliassen, A Heather; Chen, Wendy Y; Willett, Walter C

    2016-09-01

    We evaluated individual grain-containing foods and whole and refined grain intake during adolescence, early adulthood, and premenopausal years in relation to breast cancer risk in the Nurses' Health Study II. Grain-containing food intakes were reported on a baseline dietary questionnaire (1991) and every 4 years thereafter. Among 90,516 premenopausal women aged 27-44 years, we prospectively identified 3235 invasive breast cancer cases during follow-up to 2013. 44,263 women reported their diet during high school, and from 1998 to 2013, 1347 breast cancer cases were identified among these women. Cox proportional hazards regression was used to estimate relative risks (RR) and 95 % confidence intervals (95 % CI) of breast cancer for individual, whole and refined grain foods. After adjusting for known breast cancer risk factors, adult intake of whole grain foods was associated with lower premenopausal breast cancer risk (highest vs. lowest quintile: RR 0.82; 95 % CI 0.70-0.97; P trend = 0.03), but not postmenopausal breast cancer. This association was no longer significant after further adjustment for fiber intake. The average of adolescent and early adulthood whole grain food intake was suggestively associated with lower premenopausal breast cancer risk (highest vs lowest quintile: RR 0.74; 95 % CI 0.56-0.99; P trend = 0.09). Total refined grain food intake was not associated with risk of breast cancer. Most individual grain-containing foods were not associated with breast cancer risk. The exceptions were adult brown rice which was associated with lower risk of overall and premenopausal breast cancer (for each 2 servings/week: RR 0.94; 95 % CI 0.89-0.99 and RR 0.91; 95 % CI 0.85-0.99, respectively) and adult white bread intake which was associated with increased overall breast cancer risk (for each 2 servings/week: RR 1.02; 95 % CI 1.01-1.04), as well as breast cancer before and after menopause. Further, pasta intake was inversely associated with

  17. 3-D analysis of grain selection process

    Science.gov (United States)

    Arao, Tomoka; Esaka, Hisao; Shinozuka, Kei

    2012-07-01

    It is known that the grain selection plays an important role in the manufacturing process for turbine blades. There are some analytical or numerical models to treat the grain selection. However, the detailed mechanism of grain selection in 3-D is still uncertain. Therefore, an experimental research work using Al-Cu alloy has been carried out in order to understand the grain selection in 3-D.A mold made by Al2O3 was heated to 600 °C ( = liquids temperature of the alloy) and was set on a water-colded copper chill plate. Molten Al-20 wt%Cu alloy was cast into the mold and unidirectional solidified ingot was prepared. The size of ingot was approximately phi25×65H mm. To obtain the thermal history, 4 thermocouples were placed in the mold. It is confirmed that the alloy solidified unidirectionally from bottom to top. Solidified structure on a longitudinal cross section was observed and unidirectional solidification up to 40 mm was ensured. EBSD analysis has been performed on horizontal cross section at an interval of ca.200 μm. These observations were carried out 7-5 mm from the bottom surface. Crystallographic orientation of primary Al phase and size of solidified grains were characterized. A large solidified grain, the crystallographic orientation of which is approximately along heat flow direction, is observed near the lowest cross section. The area of grain decreased as solidification proceeded. On the other hand, it is found that the area of grain increased.

  18. Coarse graining lessons from simple examples

    CERN Document Server

    Akritas, P; Yarevsky, E

    2001-01-01

    We assess Coarse Graining by studying different partitions of the phase space of the Baker transformation and the periodic torus automorphisms. It turns out that the shape of autocorrelation functions for the Baker transformation is more or less reproduced. However, for certain partitions the decay rates turn out to be irrelevant, even decay may stop in a finite time. For the periodic torus automorphisms, Coarse Graining introduces artificial dumping.

  19. Evaluation of special grains bean lines for grain yield, cooking time and mineral concentrations

    Directory of Open Access Journals (Sweden)

    Nerinéia Dalfollo Ribeiro

    2014-03-01

    Full Text Available Genetic variability of 32 inbred special grains bean lines was investigated for grain yield, mass of 100 grains, cooking time, and mineral concentrations in grains, and Z index was used for selection of superior lines in most of the characters. IAC Centauro, IAC Galante, Xamego, Ouro Branco, Montcalm, and Hooter lines presented high yield grain, short cooking time (less than 24 min, and high potassium (>14 g kg-1 dry matter [DM], calcium (>1.42 g kg-1 DM, iron (>97.60 mg kg-1 DM, zinc (>29.05 mg kg-1 DM and copper (>8.67 mg kg-1 DM concentrations, and their dietary use is therefore recommended. Cal-96 line presents higher Z index for grain yield and for the most of the minerals, and its use is recommended for crosses for the development of superior lines.

  20. Whole grains protect against atherosclerotic cardiovascular disease.

    Science.gov (United States)

    Anderson, James W

    2003-02-01

    Atherosclerotic cardiovascular disease (ASCVD) is the most common cause of death in most Western countries. Nutrition factors contribute importantly to this high risk for ASCVD. Favourable alterations in diet can reduce six of the nine major risk factors for ASCVD, i.e. high serum LDL-cholesterol levels, high fasting serum triacylglycerol levels, low HDL-cholesterol levels, hypertension, diabetes and obesity. Wholegrain foods may be one the healthiest choices individuals can make to lower the risk for ASCVD. Epidemiological studies indicate that individuals with higher levels (in the highest quintile) of whole-grain intake have a 29 % lower risk for ASCVD than individuals with lower levels (lowest quintile) of whole-grain intake. It is of interest that neither the highest levels of cereal fibre nor the highest levels of refined cereals provide appreciable protection against ASCVD. Generous intake of whole grains also provides protection from development of diabetes and obesity. Diets rich in wholegrain foods tend to decrease serum LDL-cholesterol and triacylglycerol levels as well as blood pressure while increasing serum HDL-cholesterol levels. Whole-grain intake may also favourably alter antioxidant status, serum homocysteine levels, vascular reactivity and the inflammatory state. Whole-grain components that appear to make major contributions to these protective effects are: dietary fibre; vitamins; minerals; antioxidants; phytosterols; other phytochemicals. Three servings of whole grains daily are recommended to provide these health benefits.

  1. Coarse-graining methods for computational biology.

    Science.gov (United States)

    Saunders, Marissa G; Voth, Gregory A

    2013-01-01

    Connecting the molecular world to biology requires understanding how molecular-scale dynamics propagate upward in scale to define the function of biological structures. To address this challenge, multiscale approaches, including coarse-graining methods, become necessary. We discuss here the theoretical underpinnings and history of coarse-graining and summarize the state of the field, organizing key methodologies based on an emerging paradigm for multiscale theory and modeling of biomolecular systems. This framework involves an integrated, iterative approach to couple information from different scales. The primary steps, which coincide with key areas of method development, include developing first-pass coarse-grained models guided by experimental results, performing numerous large-scale coarse-grained simulations, identifying important interactions that drive emergent behaviors, and finally reconnecting to the molecular scale by performing all-atom molecular dynamics simulations guided by the coarse-grained results. The coarse-grained modeling can then be extended and refined, with the entire loop repeated iteratively if necessary.

  2. Applications of surface analysis techniques to photovoltaic research: Grain and grain boundary studies

    Science.gov (United States)

    Kazmerski, L. L.

    Complementary surface analysis techniques (AES, SIMS, XPS) are applied to photovoltaic devices in order to assess the limiting factors of grain and grain boundary chemistry to the performance of polycrystalline solar cells. Results of these compositional and chemical studies are directly correlated with electrical measurements (EBIC) and with resulting device performance. Examples of grain boundary passivation in polycrystalline Si and GaAs solar cells are cited. The quality of the intragrain material used in these devices is shown to be equally important to the grain boundary activity in determining overall photovoltaic performance.

  3. SIMULATIVE INVESTIGATION OF GRAIN BOUNDARIES IN NiAl ALLOY

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Using embedded atom potentials and molecular static relaxation method or Monte Carlo relaxation method, the grain boundary atomic structures of a series of [100], [110] and [111] symmetric tilt grain boundaries in NiAl with different geometrical indexes and compositions were studied. The grain boundary energies, grain boundary cohesive energies and point defects formation energies at the grain boundary were calculated. The results show that the grain boundaries of NiAl alloy have a periodic unit structure. Grain boundary energies of Al rich grain boundary is very high, but the cohesive energies are lower than those of others. The interaction of point defects and grain boundaries shows that grain boundaries incline to absorb point defects to decrease their orders and to relax the distortions caused by point defects. The boundary atomic structures relaxed by Monte Carlo method show that the disorder of them, grain boundary energies and cohesive energies increase with increasing temperature.

  4. Organic Wheat Farming Improves Grain Zinc Concentration.

    Science.gov (United States)

    Helfenstein, Julian; Müller, Isabel; Grüter, Roman; Bhullar, Gurbir; Mandloi, Lokendra; Papritz, Andreas; Siegrist, Michael; Schulin, Rainer; Frossard, Emmanuel

    2016-01-01

    Zinc (Zn) nutrition is of key relevance in India, as a large fraction of the population suffers from Zn malnutrition and many soils contain little plant available Zn. In this study we compared organic and conventional wheat cropping systems with respect to DTPA (diethylene triamine pentaacetic acid)-extractable Zn as a proxy for plant available Zn, yield, and grain Zn concentration. We analyzed soil and wheat grain samples from 30 organic and 30 conventional farms in Madhya Pradesh (central India), and conducted farmer interviews to elucidate sociological and management variables. Total and DTPA-extractable soil Zn concentrations and grain yield (3400 kg ha-1) did not differ between the two farming systems, but with 32 and 28 mg kg-1 respectively, grain Zn concentrations were higher on organic than conventional farms (t = -2.2, p = 0.03). Furthermore, multiple linear regression analyses revealed that (a) total soil zinc and sulfur concentrations were the best predictors of DTPA-extractable soil Zn, (b) Olsen phosphate taken as a proxy for available soil phosphorus, exchangeable soil potassium, harvest date, training of farmers in nutrient management, and soil silt content were the best predictors of yield, and (c) yield, Olsen phosphate, grain nitrogen, farmyard manure availability, and the type of cropping system were the best predictors of grain Zn concentration. Results suggested that organic wheat contained more Zn despite same yield level due to higher nutrient efficiency. Higher nutrient efficiency was also seen in organic wheat for P, N and S. The study thus suggests that appropriate farm management can lead to competitive yield and improved Zn concentration in wheat grains on organic farms.

  5. The use of cover crops to increase soil organic carbon in Mediterranean vineyards

    Science.gov (United States)

    García-Díaz, Andrés; Bienes Allas, Ramón; Sastre Rodriguez, Blanca

    2016-04-01

    In Central Spain the vineyards are commonly managed with conventional tillage (CT) to remove water and nutrient competition between the spontaneous vegetation and the vine plants. The continuous tillage promotes high mineralization rates resulting in soils with low organic matter content and prone to erosion. Consequently the increase of soil organic carbon (SOC) in Mediterranean soils has been a main concern in the last years. It is necessary to carry out different soil managements to enhance soil fertility and reduce erosion through the increase of SOC. The aim of this study was to assess the capacity of cover crops (CC) to increase SOC in vineyards in Mediterranean climate. The experiment consisted in four vineyards in four different locations (different type of soil and microclimate), in the same region, to analyze the influence of CC on different conditions. A seeded CC (Brachypodium distachyon L. P. Beauv) and spontaneous vegetation were performed to compare to CT. The Brachypodium distachyon cover was seeded in December, 2012. We analyzed the organic carbon content and bulk density after three agronomy seasons. The samples were taken in the summer of 2015 at the depth of 0-5 cm. The bulk density of Brachypodium distachyon was 1.42 t•m-3, which was statistically significant comparing to both CT (1.33 t•m-3) and spontaneous vegetation (1.34 t•m-3). The SOC percentage of CT, Brachypodium distachyon and spontaneous vegetation was 0.82, 0.96 and 1.10 respectively. Only spontaneous vegetation showed statistically significant differences compared to CT. The results were highly variable depending on the vineyard. The spontaneous vegetation was the most effective CC increasing SOC with an average of 2 t•ha-1 more than CT in three agronomy seasons. These results point out the different efficiency of CC and the high influence of local conditions on SOC increase.

  6. Increased Night Temperature Negatively Affects Grain Yield, Biomass and Grain Number in Chilean Quinoa

    Science.gov (United States)

    Lesjak, Jurka; Calderini, Daniel F.

    2017-01-01

    Quinoa high nutritive value increases interest worldwide, especially as a crop that could potentially feature in different cropping systems, however, climate change, particularly rising temperatures, challenges this and other crop species. Currently, only limited knowledge exists regarding the grain yield and other key traits response to higher temperatures of this crop, especially to increased night temperatures. In this context, the main objective of this study was to evaluate the effect of increased night temperature on quinoa yield, grain number, individual grain weight and processes involved in crop growth under the environmental conditions (control treatment) and night thermal increase at two phases: flowering (T1) and grain filling (T2) in southern Chile. A commercial genotype, Regalona, and a quinoa accession (Cod. BO5, N°191, grain bank from Semillas Baer, hereby referred to as Accession) were used, due to their adaptability to Southern Chilean conditions and contrasting grain yield potential, grain weight and size of plants. Temperature was increased ≈4°C above the ambient from 8 pm until 9 am the next morning. Control treatments reached a high grain yield (600 and 397 g m-2, i.e., Regalona and Accession). Temperature increase reduced grain yield by 31% under T1 treatment and 12% when under T2 in Regalona and 23 and 26% in Accession, respectively. Aboveground biomass was negatively affected by the thermal treatments and a positive linear association was found between grain yield and aboveground biomass across treatments. By contrast, the harvest index was unaffected either by genotype, or by thermal treatments. Grain number was significantly affected between treatments and this key trait was linearly associated with grain yield. On the other hand, grain weight showed a narrow range of variation across treatments. Additionally, leaf area index was not affected, but significant differences were found in SPAD values at the end of T1 treatment, compared

  7. Performance of organic grain legumes in Tuscany

    Directory of Open Access Journals (Sweden)

    Valentina Moschini

    2014-03-01

    Full Text Available In 2005-2007 growing season, few varieties of field bean, high protein pea and white lupin were compared in an organic farm of Central Italy (Mugello area, Tuscany, to evaluate their agronomic performance in terms of grain yield, nutritional quality and competitive ability against weeds. The experiment was performed under rain-fed conditions. Furthermore, grain legumes features were compared between two different sowing seasons (autumnal vs late-winter for two years, in order to get information on the best time of sowing of these species, and the stability of yields of different genotypes in those climatic and soil conditions. These legumes could be an alternative protein source to external soybean, a high-risk alimentary source of genetically modified organisms, in the organic livestock sector. The main findings indicate that higher yields in grain and crude protein were obtained with the pea species and in particular with cultivars Hardy (4.0 t/ha grain yield; 626 kg/ha crude protein yield and Classic (3.1 t/ha grain yield; 557 kg/ha crude protein yield; followed by field bean cv. Chiaro di Torre Lama (2.9 t/ha grain yield; 624 kg/ha crude protein yield and cv. Vesuvio (2.5 t/ha grain yield; 549 kg/ha crude protein yield. Furthermore the field bean is interesting for the stability of yield in both years despite climatic conditions rather different. The white lupin has showed the lower yield but the best values of grain quality, with higher values in lupin Multitalia for dry matter, crude protein and ether extract and in lupin Luxe also for crude fibre, respect to the other legumes analysed. Among lupin varieties, lupin Multitalia showed the best yield results for the pedo-climatic conditions of Mugello area (0.9 t/ha lupin Multitalia; 0.2 t/ha lupin Luxe. The total yield of organic grain legumes, in the experimental site, is resulted higher with an autumnal seeding respect to the late-winter seeding (2.8 t/ha vs 1.9 t/ha.

  8. Grain Boundaries From Theory to Engineering

    CERN Document Server

    Priester, Louisette

    2013-01-01

    Grain boundaries are a main feature of crystalline materials. They play a key role in determining the properties of materials, especially when grain size decreases and even more so with the current improvements of  processing tools and methods that allow us to control various elements in a polycrystal. This book presents the theoretical basis of the study of  grain boundaries and aims to open up new lines of research in this area. The treatment is light on mathematical approaches while emphasizing practical examples; the issues they raise are discussed with reference to theories. The general approach of the book has two main goals: to lead the reader from the concept of ‘ideal’ to ‘real’ grain boundaries; to depart from established knowledge and address the opportunities emerging through "grain boundary engineering",  the control of morphological and crystallographic features that affect material properties. The book is divided in three parts:  I ‘From interganular order to disorder’ deals wit...

  9. Internetwork chromospheric bright grains observed with IRIS

    CERN Document Server

    Martínez-Sykora, Juan; Carlsson, Mats; De Pontieu, Bart; Pereira, Tiago M D; Boerner, Paul; Hurlburt, Neal; Kleint, Lucia; Lemen, James; Tarbell, Ted D; Title, Alan; Wuelser, Jean-Pierre; Hansteen, Viggo H; Golub, Leon; McKillop, Sean; Reeves, Kathy K; Saar, Steven; Testa, Paola; Tian, Hui; Jaeggli, Sarah; Kankelborg, Charles

    2015-01-01

    The Interface Region Imaging Spectrograph (IRIS) reveals small-scale rapid brightenings in the form of bright grains all over coronal holes and the quiet sun. These bright grains are seen with the IRIS 1330 \\AA, 1400 \\AA\\ and 2796 \\AA\\ slit-jaw filters. We combine coordinated observations with IRIS and from the ground with the Swedish 1-m Solar Telescope (SST) which allows us to have chromospheric (Ca II 8542 \\AA, Ca II H 3968 \\AA, H\\alpha, and Mg II k 2796 \\AA), and transition region (C II 1334 \\AA, Si IV 1402) spectral imaging, and single-wavelength Stokes maps in Fe I 6302 \\AA at high spatial (0.33"), temporal and spectral resolution. We conclude that the IRIS slit-jaw grains are the counterpart of so-called acoustic grains, i.e., resulting from chromospheric acoustic waves in a non-magnetic environment. We compare slit-jaw images with spectra from the IRIS spectrograph. We conclude that the grain intensity in the 2796 \\AA\\ slit-jaw filter comes from both the Mg II k core and wings. The signal in the C II ...

  10. Interstellar grain chemistry and organic molecules

    Science.gov (United States)

    Allamandola, L. J.; Sandford, S. A.

    1990-01-01

    The detection of prominant infrared absorption bands at 3250, 2170, 2138, 1670 and 1470 cm(-1) (3.08, 4.61, 4.677, 5.99 and 6.80 micron m) associated with molecular clouds show that mixed molecular (icy) grain mantles are an important component of the interstellar dust in the dense interstellar medium. These ices, which contain many organic molecules, may also be the production site of the more complex organic grain mantles detected in the diffuse interstellar medium. Theoretical calculations employing gas phase as well as grain surface reactions predict that the ices should be dominated only by the simple molecules H2O, H2CO, N2, CO, O2, NH3, CH4, possibly CH3OH, and their deuterated counterparts. However, spectroscopic observations in the 2500 to 1250 cm(-1)(4 to 8 micron m) range show substantial variation from source reactions alone. By comparing these astronomical spectra with the spectra of laboratory-produced analogs of interstellar ices, one can determine the composition and abundance of the materials frozen on the grains in dense clouds. Experiments are described in which the chemical evolution of an interstellar ice analog is determined during irradiation and subsequent warm-up. Particular attention is paid to the types of moderately complex organic materials produced during these experiments which are likely to be present in interstellar grains and cometary ices.

  11. China’s Price System Jeopardizes its Grain Reserves

    Institute of Scientific and Technical Information of China (English)

    李宾

    2008-01-01

    2008 is a year of bumper harvest in summer grain across China. The failure of numerous state-owned grain depots to purchase grain in times of bumper harvest, however, directly threatens grain reserve security and state control over grain prices in the upcoming year. An important factor underpinning the difficulty of state grain depots to purchase grain is the unwillingness of farmers to sell grain due to the excess of the current market price over the government "protected price" aimed at preventing cheap grain from harming farmers. When grassroots grain depots find themselves in trouble, foreign capital stealthily moves in by taking advantage of this situation. To fulfill grain storage tasks and receive various state subsidies, some state-owned grain depots have no alternative but to surreptitiously raise the purchase price. By contrast, some not so courageous state-owned grain depots can only borrow money to finance the purchase of commodity grain at market prices and subsequently figure out a way to pay back such loans. Behind such distorted grain purchase behavior lies a rough and rugged history of grain price reform in China.

  12. Whole grain gluten-free egg-free pasta

    Science.gov (United States)

    The USDA food guide recommends that at least ½ of all the grains eaten should be whole grains. The FDA allows food Health Claim labels for food containing 51% whole grains and 11 g of dietary fiber. This is the only report demonstrating innovative whole grain gluten free, egg free (no chemicals adde...

  13. Volatile organic compounds of whole grain soft winter wheat

    Science.gov (United States)

    The aroma from volatile organic compounds (VOCs) is an indicator of grain soundness and also an important quality attribute of grain foods. To identify the inherent VOCs of wheat grain unaffected by fungal infestation and other extrinsic factors, grains of nine soft wheat varieties were collected at...

  14. Evolution of orientations and deformation structures within individual grains in cold rolled columnar grained nickel

    DEFF Research Database (Denmark)

    Wu, G.L.; Godfrey, A.; Winther, Grethe;

    2011-01-01

    Columnar grained Ni is used as a model material allowing simultaneous non-surface investigations of the evolution of crystallographic orientations and deformation microstructures within individual grains as a function of rolling strain up to ε=0.7. Electron channelling contrast and electron...

  15. A unified model of grain alignment: Radiative Alignment of Interstellar Grains with magnetic inclusions

    CERN Document Server

    Hoang, Thiem

    2016-01-01

    The radiative torque (RAT) alignment of interstellar grains with ordinary paramagnetic susceptibilities has been supported by a number of earlier studies. The alignment of such grains depends on the so-called RAT parameter $q^{\\max}$ that is determined by the grain shape. For interstellar grains with a broad range of $q^{\\max}$, a significant fraction of grains is expected to get aligned with low angular momentum at the so-called low-J attractor points, which entail degrees of alignment between 20 or 30 percent, irrespectively of the strength of RATs. The latter value may not be sufficient for explaining the observed interstellar alignment in the diffuse medium. In this paper, we elaborate our model of radiative alignment for grains with enhanced magnetic susceptibility due to magnetic inclusions, such that both Magnetic torque and RAdiative Torque (MRAT) play a role in grain alignment. Such grains can get aligned with high angular momentum at the so-called high-J attractor points, which achieve a high degree...

  16. Activation of Big Grain1 significantly improves grain size by regulating auxin transport in rice.

    Science.gov (United States)

    Liu, Linchuan; Tong, Hongning; Xiao, Yunhua; Che, Ronghui; Xu, Fan; Hu, Bin; Liang, Chengzhen; Chu, Jinfang; Li, Jiayang; Chu, Chengcai

    2015-09-01

    Grain size is one of the key factors determining grain yield. However, it remains largely unknown how grain size is regulated by developmental signals. Here, we report the identification and characterization of a dominant mutant big grain1 (Bg1-D) that shows an extra-large grain phenotype from our rice T-DNA insertion population. Overexpression of BG1 leads to significantly increased grain size, and the severe lines exhibit obviously perturbed gravitropism. In addition, the mutant has increased sensitivities to both auxin and N-1-naphthylphthalamic acid, an auxin transport inhibitor, whereas knockdown of BG1 results in decreased sensitivities and smaller grains. Moreover, BG1 is specifically induced by auxin treatment, preferentially expresses in the vascular tissue of culms and young panicles, and encodes a novel membrane-localized protein, strongly suggesting its role in regulating auxin transport. Consistent with this finding, the mutant has increased auxin basipetal transport and altered auxin distribution, whereas the knockdown plants have decreased auxin transport. Manipulation of BG1 in both rice and Arabidopsis can enhance plant biomass, seed weight, and yield. Taking these data together, we identify a novel positive regulator of auxin response and transport in a crop plant and demonstrate its role in regulating grain size, thus illuminating a new strategy to improve plant productivity.

  17. Grain size dependent mechanical properties in nanophase materials

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, R.W. [Argonne National Lab., IL (United States); Fougere, G.E. [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering

    1995-02-01

    It has become possible in recent years to synthesize metals and ceramics under well controlled conditions with constituent grain structures on a manometer size scale (below 100 nm). These new materials have mechanical properties that are strongly grain-size dependent and often significantly different than those of their coarser grained counterparts. Nanophase metals tend to become stronger and ceramics are more easily deformed as grain size is reduced. The observed mechanical property changes appear to be related primarily to grain size limitations and the large percentage of atoms in grain boundary environments. A brief overview of our present knowledge about the grain-size dependent mechanical properties of nanophase materials is presented.

  18. A Model for Evaluation of Grain Sizes of Aluminum Alloys with Grain Refinement Additions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on the assumption that the nucleation substrates are activated by constitutional undercooling generated by an adjacent grain growth and solute distribution during the initial solidification, a model for calculation of the grain size of aluminum alloys with the grain refinement is developed, where the nucleation is dominated by two parameters, I.e. Growth restriction factor Q and the undercooling parameter P. The growth restriction factor Q is proportional to the initial rate of constitutional undercooling development and can be used directly as a criterion of the grain refinement in the alloys with strong potential nucleation particles. The undercooling parameter P can be regarded as the maximum of constitutional undercooling △TC. For weak potential nucleation particles, the use of RGS would be more accurate. The experimental data of the grain refinement of pure aluminum and AISi7 alloys are coincident predicted results with the model.

  19. INFLUENCE OF ABNORMAL AUSTENITE GRAIN GRAIN GROWTH IN QUENCHED ABNT 5135 STEEL

    Directory of Open Access Journals (Sweden)

    Camila de Brito Ferreira

    2015-03-01

    Full Text Available Grain size in the steels is a relevant aspect in quenching and tempering heat treatments. It is known that high austenitizing temperature and long time provide an increase in austenitic grain sizes. Likewise, after hardening of low alloy steel, the microstructure consists of martensite and a volume fraction of retained austenite. This paper evaluates the influence of austenite grain size on the volume fraction of retained austenite measured by metallographic analyses and X-ray diffraction. The Mi and Mf temperatures were calculated using an empirical equation and experimentally determined by differential thermal analysis. The mechanical behavior of the steel was evaluated by Vickers microhardness testing. Differently from other results published in the literature that steel hardenability increases with the austenite grain size, it was observed that the increase in austenite grain promotes greater volume fraction of retained austenite after water quenching.

  20. Abnormal grain growth in undoped strontium and barium titanate

    Energy Technology Data Exchange (ETDEWEB)

    Baeurer, M., E-mail: m.baeurer@ikm.uka.de [Institut fuer Keramik im Maschinenbau, Universitaet Karlsruhe, Karlsruhe (Germany); Shih, S.-J.; Bishop, C. [Department of Materials, University of Oxford, Oxford (United Kingdom); Harmer, M.P. [Center for Advanced Materials and Nanotechnology, Lehigh University, Bethlehem, PA (United States); Cockayne, D. [Department of Materials, University of Oxford, Oxford (United Kingdom); Hoffmann, M.J. [Institut fuer Keramik im Maschinenbau, Universitaet Karlsruhe, Karlsruhe (Germany)

    2010-01-15

    Abnormal grain growth is a commonly observed phenomenon in perovskite materials. In order to study this phenomenon, grain growth experiments were conducted over a temperature range from 1425 to 1600 deg. C for the model system SrTiO{sub 3} to analyse the nucleation of abnormal grains and to identify the growth mechanism involved for normal and abnormal grains. Grain boundaries of normal and abnormal grains were investigated in quenched samples by high-resolution transmission electron microscopy and by energy-dispersive spectroscopy in a scanning transmission electron microscope. No amorphous film was observed at the grain boundaries for either normal or abnormal grains. Non-stoichiometry at the grain boundaries was identified as a possible reason for the differences in growth speed. The results are compared to the nucleation and growth of abnormal grains in BaTiO{sub 3}.

  1. Radiative torques on interstellar grains; 1, superthermal spinup

    CERN Document Server

    Draine, B T; Weingartner, Joseph C

    1996-01-01

    Irregular dust grains are subject to radiative torques when irradiated by interstellar starlight. It is shown how these radiative torques may be calculated using the discrete dipole approximation. Calculations are carried out for one irregular grain geometry, and three different grain sizes. It is shown that radiative torques can play an important dynamical role in spinup of interstellar dust grains, resulting in rotation rates which may exceed even those expected from H_2 formation on the grain surface. Because the radiative torque on an interstellar grain is determined by the overall grain geometry rather than merely the state of the grain surface, the resulting superthermal rotation is expected to be long-lived. By itself, long-lived superthermal rotation would permit grain alignment by normal paramagnetic dissipation on the "Davis-Greenstein" timescale. However, radiative torques arising from anisotropy of the starlight background can act directly to alter the grain alignment on much shorter timescales, a...

  2. Charging and Growth of Fractal Dust Grains

    CERN Document Server

    Matthews, Lorin S

    2007-01-01

    The structure and evolution of aggregate grains formed within a plasma environment are dependent upon the charge acquired by the micron-sized dust grains during the coagulation process. The manner in which the charge is arranged on developing irregular structures can affect the fractal dimension of aggregates formed during collisions, which in turn influences the coagulation rate and size evolution of the dust within the plasma cloud. This paper presents preliminary models for the charge and size evolution of fractal aggregates immersed in a plasma environment calculated using a modification to the orbital-motion-limited (OML) theory. Primary electron and ion currents incident on points on the aggregate surface are determined using a line-of-sight (LOS) approximation: only those electron or ion trajectories which are not blocked by another grain within the aggregate contribute to the charging current. Using a self-consistent iterative approach, the equilibrium charge and dipole moment are calculated for the d...

  3. Calculating Cross Sections of Composite Interstellar Grains

    CERN Document Server

    Voshchinnikov, N V; Voshchinnikov, Nikolai V.; Mathis, John S.

    1999-01-01

    Interstellar grains may be composite collections of particles of distinct materials, including voids, agglomerated together. We determine the various optical cross sections of such composite grains, given the optical properties of each constituent, using an approximate model of the composite grain. We assume it consists of many concentric spherical layers of the various materials, each with a specified volume fraction. In such a case the usual Mie theory can be generalized and the extinction, scattering, and other cross sections determined exactly. We find that the ordering of the materials in the layering makes some difference to the derived cross sections, but averaging over the various permutations of the order of the materials provides rapid convergence as the number of shells (each of which is filled by all of the materials proportionately to their volume fractions) is increased. Three shells, each with one layer of a particular constituent material, give a very satisfactory estimate of the average cross...

  4. Structure of grain boundaries in hexagonal materials

    CERN Document Server

    Sarrazit, F

    1998-01-01

    which allows the behaviour of line-defects to be studied in complex interfacial processes. The work presented in this thesis describes experimental and theoretical aspects associated with the structure of grain boundaries in hexagonal materials. It has been found useful to classify grain boundaries as low-angle, special or general on the basis of their structure. High-angle grain boundaries were investigated in tungsten carbide (WC) using conventional electron microscopy techniques, and three examples characteristic of the interfaces observed in this material were studied extensively. Three-dimensionally periodic patterns are proposed as plausible reference configurations, and the Burgers vectors of observed interfacial dislocations were predicted using a theory developed recently. The comparison of experimental observations with theoretical predictions proved to be difficult as contrast simulation techniques require further development for analysis to be completed confidently. Another part of this work invol...

  5. Alternating grain orientation and weld solidification cracking

    Science.gov (United States)

    Kou, S.; Le, Y.

    1985-10-01

    A new mechanism for reducing weld solidification cracking was proposed, based on the concept of the crack path and resistance to crack propagation, and its effectiveness was verified in magnetically oscillated GTA welds of a rather crack susceptible material 2014 aluminum alloy. This mechanism, i.e., alternating grain orientation, was most pronounced in welds made with transverse arc oscillation of low frequency and high amplitude, and solidification cracking was dramatically reduced in these welds. The effect of the arc oscillation pattern, amplitude, and frequency on the formation of alternating columnar grains and the reduction of solidification cracking in GTA welds of 2014 aluminum alloy was examined and explained. The present study demonstrated for the first time that columnar grains can, in fact, be very effective in reducing solidification cracking, provided that they are oriented favorably.

  6. AC susceptibilities of grain-textured superconductors

    Science.gov (United States)

    Sakamoto, N.; Fukuda, Y.; Koga, M.; Akune, T.; Khan, H. R.; Lüders, K.

    2008-09-01

    In-phase χ n‧ and out-phase χ n″ components of nth harmonics of AC susceptibility with measuring parameters of a DC magnetic field Bdc, an amplitude Ba and a frequency f of the superimposed AC magnetic fields give substantial information of the superconducting properties. In low- Tc metallic superconductors, χ1‧ shows smooth transition and χ1″ does single peak. High- Tc oxide superconductors with anisotropic and grain-textured structures show deformed complex characteristics. Double peaks in χ1″ and shoulders in χ1‧ appear in AC susceptibility of Hg-1223 superconductors. Instead of simple Bean model, a grained model, where the superconducting grains are immersed in weak superconducting matrix, are proposed. The susceptibilities numerically analyzed using the model show varied and deformed curves and are successfully compared with the measured results.

  7. Mining the Change of the Quality of Stored Grain

    Institute of Scientific and Technical Information of China (English)

    SHANG Zhi-gen; LOU Wei; ZHOU Wei-min

    2006-01-01

    The quality of grain changes continually during its storage,including the change of its physical characteristics and physiological characteristics. This paper presents an approach to predict the change of the quality of stored grain with data mining technology. Logistic Regression, Decision Tree and Multilayer Perceptron are applied to predict the change of the grains' quality control index and to obtain the grains' quality change probability. The grain sampling with higher probability can be processed earlier.

  8. The major achievements of grain storage in P. R. China

    OpenAIRE

    Wang, J.-J.; Deng, Y.-X.; W. Dou; Yang, Z.-L.; Jiang, T.-K.

    2010-01-01

    During the past several decades, China has made great progress in grain storage research, which greatly improved and promoted grain storage techniques and facilities. Especially in the 1990s, modern grain storage depots were constructed, in which four new technologies of grain inspection automation, machinery aeration, grain cooling, and phosphine recirculating fumigation were popularized. The main technologies to phase out methyl bromide in national depots are under-film phosphine recirculat...

  9. Does Whole Grain Consumption Alter Gut Microbiota and Satiety?

    OpenAIRE

    Danielle N. Cooper; Martin, Roy J.; Keim, Nancy L.

    2015-01-01

    This review summarizes recent studies examining whole grain consumption and its effect on gut microbiota and satiety in healthy humans. Studies comparing whole grains to their refined grain counterparts were considered, as were studies comparing different grain types. Possible mechanisms linking microbial metabolism and satiety are described. Clinical trials show that whole grain wheat, maize, and barley alter the human gut microbiota, but these findings are based on a few studies that do not...

  10. Malta and the Nineteenth Century Grain Trade

    DEFF Research Database (Denmark)

    Sharp, Paul Richard

    2009-01-01

    It is often assumed that Britain's colonies followed the British doctrine of free trade in the second half of the nineteenth century. Malta, which became a British colony in 1814, did indeed become an early free trader. However, she failed to liberalize the grain trade, even when the mother country....... The duties on grain in Malta were therefore not protectionist, but rather for revenue purposes, in contrast to the UK Corn Laws. Taxing an inelastic demand for foreign wheat by Maltese, who were unable to grow enough food to support themselves, was certainly an effective way of raising revenue, but probably...

  11. Malta and the Nineteenth Century Grain Trade

    DEFF Research Database (Denmark)

    Sharp, Paul Richard

    It is often assumed that Britain's colonies followed the British doctrine of free trade in the second half of the nineteenth century. Malta, which became a British colony in 1814, did indeed become an early free trader. However, she failed to liberalize the grain trade, even when the mother country....... The duties on grain in Malta were therefore not protectionist, but rather for revenue purposes, in contrast to the UK Corn Laws. Taxing an inelastic demand for foreign wheat by Maltese, who were unable to grow enough food to support themselves, was certainly an effective way of raising revenue, but probably...

  12. Fine-grained concrete with organomineral additive

    Directory of Open Access Journals (Sweden)

    Solovyov Vitaly

    2016-01-01

    Full Text Available The article deals with the issues concerning the formation of the structure and properties of fine-grained concrete with organomineral additive produced through mechanochemical activation of thermal power plant fly ash together with superplasticizer. The additive is produced in a high-speed activator at the collision particles’ speed of about 80 m/s. The use of the additive in fine-grained concrete in the amounts of 0.5-1% increased the strength by 30-50% and reduced the size and volume of pores. The cement consumption in such concrete is close to the cement consumption in common concrete of equal resistance.

  13. A Granular Model of Rolling Grain Ripples

    CERN Document Server

    Andersen, K H

    1999-01-01

    A simple model is presented for the formation of rolling grain ripples on a flat sand bed by the oscillatory flow from a surface wave. The model is related to physical parameters of the problem, and is solved for the equilibrium spacing and height of the ripples. Good agreement between the model and measurements of rolling grain ripples is demonstrated. It is found that the length of the ripples scale with the square-root of the non-dimensional shear stress on a flat bed.

  14. Simulation of grain size effects in nanocrystalline shape memory alloys

    Science.gov (United States)

    Ahluwalia, Rajeev; Quek, Siu Sin; Wu, David T.

    2015-06-01

    Recently, it has been demonstrated that martensitic transformation in nanocrystalline shape memory alloys can be suppressed for small grain sizes. Motivated by these results, we study the grain size dependence of martensitic transformations and stress-strain response of nanocrystalline shape memory alloys within the framework of the Ginzburg-Landau (GL) theory. A GL model for a square to rectangle transformation in polycrystals is extended to account for grain boundary effects. We propose that an inhibition of the transformation in grain boundary regions can occur, if the grain boundary energy of the martensite is higher than that of the austenite phase. We show that this inhibition of transformation in grain boundary regions has a strong influence on domain patterns inside grains. Although the transformation is inhibited only at the grain boundaries, it leads to a suppression of the transformation even inside the grains as grain size is decreased. In fact, below a critical grain size, the transformation can be completely suppressed. We explain these results in terms of the extra strain gradient cost associated with grain boundaries, when the transformation is inhibited at grain boundaries. On the other hand, no significant size effects are observed when transformation is not inhibited at grain boundaries. We also study the grain size dependence of the stress strain curve. It is found that when the transformation is inhibited at grain boundaries, a significant reduction in the hysteresis associated with stress-strain curves during the loading-unloading cycles is observed. The hysteresis for this situation reduces even further as the grain size is reduced, which is consistent with recent experiments. The simulations also demonstrate that the mechanical behavior is influenced by inter-granular interactions and the local microstructural neighbourhood of a grain has a stronger influence than the orientation of the grain itself.

  15. The influence of grain boundary structure on the penetration of gallium into aluminum grain boundaries

    Science.gov (United States)

    Hugo, Richard Charles

    1998-12-01

    Liquid Metal Embrittlement is a form of environmental embrittlement that dramatically reduces the fracture toughness of many metals and alloys. It occurs when surfaces of certain solid metals are wet by certain liquid metals. The Al-Ga system provides a remarkable example of intergranular attack. The Al-Ga equilibrium phase diagram reveals no intermetallic compounds and very limited mutual solubilities, which implies that interactions between Al and Ga should be minimal. Yet when liquid Ga wets the surface of an unstressed Al specimen, the Ga will penetrate the Al grain boundaries, replacing each boundary with a liquid layer. The driving force is generally considered to be the reduction in energy when a grain boundary is replaced by two Ga-Al interfaces. Once an Al sample has been penetrated by Ga, it fails at almost no load. In this dissertation, in-situ Transmission Electron Microscope (TEM) studies are presented that elucidate the physical nature of the Ga penetration front. Although many of the TEM specimens were bicrystals, all but one of the grain boundaries studied were "general" boundaries; that is, they were low symmetry boundaries with high-index rotation axes, and no low-index planes common to both grains. Since the atomic structure of these grain boundaries cannot be resolved experimentally, atomistic computer models were constructed to assist in interpreting TEM results. TEM observations indicated that the penetration front is a line defect, possessing a stress field that interacts with lattice dislocations. The penetration front was also observed to interact with structural variations within the grain boundary. Interactions with lattice dislocations were used to estimate the penetration front thickness. Penetration speeds were not found to be determined by grain boundary energy or grain boundary excess volume. Penetration speeds were, however, found to depend qualitatively on the presence of penetration barriers in the grain boundary.

  16. Learning To Teach Against the (New) Grain.

    Science.gov (United States)

    Cochran-Smith, Marilyn

    2001-01-01

    Examines the importance of learning to teach for social justice, social change, and social responsibility. All teachers must learn to teach against the grain by collaborating closely with university- and school-based mentors to develop critique, challenge common practices, and engage in inquiry. Preservice programs must provide the social,…

  17. Against the Grain: Teaching Historical Complexity

    Science.gov (United States)

    Neumann, Dave

    2013-01-01

    Many teachers and scholars have written about the importance of inquiry in effective history instruction. At its core, inquiry involves student investigation of a significant historical problem. Experienced teachers, however, often reveal their skill in purposely teaching against the grain. Skilled teachers help students appreciate historical…

  18. Malta and the Nineteenth Century Grain Trade

    DEFF Research Database (Denmark)

    Sharp, Paul Richard

    It is often assumed that Britain's colonies followed the British doctrine of free trade in the second half of the nineteenth century. Malta, which became a British colony in 1814, did indeed become an early free trader. However, she failed to liberalize the grain trade, even when the mother country...

  19. Malta and the Nineteenth Century Grain Trade

    DEFF Research Database (Denmark)

    Sharp, Paul Richard

    2009-01-01

    It is often assumed that Britain's colonies followed the British doctrine of free trade in the second half of the nineteenth century. Malta, which became a British colony in 1814, did indeed become an early free trader. However, she failed to liberalize the grain trade, even when the mother country...

  20. TO THE PROBLEM OF COMPLEX GRAIN HARVESTING

    Directory of Open Access Journals (Sweden)

    Rinas N. A.

    2014-11-01

    Full Text Available The ways and the methods of the solution of the problem of complex cleaning of grain crops were proved; the de-pendences of engine capacity of the Massey Ferguson tractors of 8200 series on the capacity of a thresher of the hook-on combine were received

  1. Grain legume genetic resources for allele mining

    Science.gov (United States)

    Sequencing capacities for higher throughput at significantly lower costs have enabled larger scale genotyping of plant genetic resources. One challenge to sequencing the USDA grain legume collections of pea, chickpea and lentil core accessions is the amount of heterogeneity in the landrace accessio...

  2. Whole Grains: Processing, fiber, color, and phytonutrients

    Science.gov (United States)

    Increased consumption of whole grains, especially wheat, can reduce cancer and cardiovascular disease due to dietary fiber and phenolic antioxidants. Yet, remarkably little is known about the fate of fiber (arabinoxylans) and phenolics during wheat food processing. Our long-term goal is to facilitat...

  3. Mineral Analysis of Whole Grain Total Cereal

    Science.gov (United States)

    Hooker, Paul

    2005-01-01

    The quantitative analysis of elemental iron in Whole Grain Total Cereal using visible spectroscopy is suitable for a general chemistry course for science or nonscience majors. The more extensive mineral analysis, specifically for the elements iron, calcium and zinc, is suitable for an instrumental or quantitative analysis chemistry course.

  4. Large grain cavities from pure niobium ingot

    Science.gov (United States)

    Myneni, Ganapati Rao [Yorktown, VA; Kneisel, Peter [Williamsburg, VA; Cameiro, Tadeu [McMurray, PA

    2012-03-06

    Niobium cavities are fabricated by the drawing and ironing of as cast niobium ingot slices rather than from cold rolled niobium sheet. This method results in the production of niobium cavities having a minimum of grain boundaries at a significantly reduced cost as compared to the production of such structures from cold rolled sheet.

  5. Cycling of grain legume residue nitrogen

    DEFF Research Database (Denmark)

    Jensen, E.S.

    1995-01-01

    Symbiotic nitrogen fixation by legumes is the main input of nitrogen in ecological agriculture. The cycling of N-15-labelled mature pea (Pisum sativum L.) residues was studied during three years in small field plots and lysimeters. The residual organic labelled N declined rapidly during the initial...... management methods in order to conserve grain legume residue N sources within the soil-plant system....

  6. Fermentation alcohol from grain sorghum starch

    Energy Technology Data Exchange (ETDEWEB)

    Du Preez, J.C.; De Jong, F.; Botes, P.J.; Lategan, P.M.

    1985-01-01

    Grain sorghum is an attractive agricultural feedstock for ethanol production because of its high starch content and the fact that it is more drought-resistant than other cereal crops such as maize. The popular bird-proof grain sorghum variety was investigated. This was subjected to a chemical pretreatment to remove the polyphenolic compounds prior to starch hydrolysis and subsequent fermentation. Starch hydrolysis was accomplished with a commercial alpha-amylase for liquefaction and amyloglucosidase for saccharification. Depending on the saccharification conditions, the hydrolysate contained 65 to 128 g/litre glucose with corresponding maltose concentrations of 50 to 20 g/litre. Several yeast strains were evaluated for their ability to ferment maltose. The total saccharification plus fermentation time could be shortened substantially by inoculating after a brief saccharification period. The addition of ammonium chloride to the hydrolysate improved the fermentation rate. From a 30% grain sorghum slurry an ethanol concentration of over 12% (v/v) was obtained, which was 84% of the theoretical maximum. The data indicated that about 380 litres of ethanol could be produced per ton grain sorghum. 38 references.

  7. Charging of grains in sprite-plasma

    Science.gov (United States)

    Serozhkin, Y.; Oryeshko, E.

    The presence of a charged dust component at a mesosphere substantially determines properties of this atmospheric layer and has manifold manifestations One of possible sources of free electrons for a charge of grains can be served the electrical discharges in a mesosphere sprites 1 As sprites take huge volume about 10000 cubic kilometer and happen approximately 1 time per one second their role in the charging of grains in a mesosphere necessarily should be taken into account In supported work is estimated the value of a charge which grains obtained in sprite-plasma The parameters of sprite-plasma velocity concentration of an electronic component duration of existence make possible a charge of submicron grains up to value at which in case of sufficient concentration of particles the sprite-plasmas can to be possessed of the dusty plasma properties 2 begin enumerate item V P Pasko U S Inan T F Bell Y N Taranenko Sprites produced by quasi-electrostatic heating ldots J Geophys Res Vol 102 No A3 pages 4529-4561 March 1 1997 item Yu Serozhkin Dusty sprite-plasma and conditions for its formation AIP Conference Proceedings New vistas in dusty plasmas Fourth International Conferences on the Physics of Dusty Plasmas Orleans France 13-17 June 2005 Vol 799 pages 383-386 end enumerate

  8. Physical properties of sunflower grains after drying

    Directory of Open Access Journals (Sweden)

    Paulo Carteri Coradi

    2015-12-01

    Full Text Available The knowledge of the physical properties of the grains is important for the optimization of post-harvest operations. This study aimed to evaluate the effects of convective drying with different air temperatures (45, 55, 65 and 75 °C the physical properties of sunflower seeds. The drying sunflower grains was performed in convection oven with forced air. In natural conditions, samples of 5 kg of pellets were used for each repetition drying. During the drying process, the grains samples were weighed periodically until they reach 10% (wet basis, w.b., then were subjected to evaluations of physical properties. According to the results it was observed that the porosity, apparent density, thousand kernel weight to the drag coefficient, roundness, sphericity and width of sunflower seed did not change with increasing temperature drying air. It was concluded that the drying air temperatures of 45 °C and 55 retained the initial physical characteristics of sunflower seeds. The temperature of the drying air of 75 °C had greater influence on changes in volumetric shrinkage of the grains.

  9. Grain Unloading Of Arsenic Species In Rice

    Science.gov (United States)

    Rice (Oryza sativa) is the staple food for over half the world's population yet may represent a significant dietary source of inorganic arsenic (As), a nonthreshold, class 1 human carcinogen. Rice grain As is dominated by the inorganic species, and the organic species dim...

  10. Cereal grains for nutrition and health benefits

    DEFF Research Database (Denmark)

    Björck, Inger; Östman, Elin; Kristensen, Mette

    2012-01-01

    Epidemiological studies have linked whole grain intake to the prevention of the metabolic syndrome, obesity and associated chronic diseases such as CVD and T2D. The Nutrition module within the HEALTHGRAIN project, included 10 partners and undertook in vitro, animal and human in vivo studies...

  11. Assessment of MARMOT Grain Growth Model

    Energy Technology Data Exchange (ETDEWEB)

    Fromm, B. [Idaho National Lab. (INL), Idaho Falls, ID (United States). Fuel Modeling and Simulation Dept.; Zhang, Y. [Idaho National Lab. (INL), Idaho Falls, ID (United States). Fuel Modeling and Simulation Dept.; Schwen, D. [Idaho National Lab. (INL), Idaho Falls, ID (United States). Fuel Modeling and Simulation Dept.; Brown, D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pokharel, R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-12-01

    This report assesses the MARMOT grain growth model by comparing modeling predictions with experimental results from thermal annealing. The purpose here is threefold: (1) to demonstrate the validation approach of using thermal annealing experiments with non-destructive characterization, (2) to test the reconstruction capability and computation efficiency in MOOSE, and (3) to validate the grain growth model and the associated parameters that are implemented in MARMOT for UO2. To assure a rigorous comparison, the 2D and 3D initial experimental microstructures of UO2 samples were characterized using non-destructive Synchrotron x-ray. The same samples were then annealed at 2273K for grain growth, and their initial microstructures were used as initial conditions for simulated annealing at the same temperature using MARMOT. After annealing, the final experimental microstructures were characterized again to compare with the results from simulations. So far, comparison between modeling and experiments has been done for 2D microstructures, and 3D comparison is underway. The preliminary results demonstrated the usefulness of the non-destructive characterization method for MARMOT grain growth model validation. A detailed analysis of the 3D microstructures is in progress to fully validate the current model in MARMOT.

  12. Structures and transitions in tungsten grain boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Frolov, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zhu, Q. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Marian, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rudd, R. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-02-07

    The objective of this study is to develop a computational methodology to predict structure, energies of tungsten grain boundaries as a function of misorientation and inclination. The energies and the mobilities are the necessary input for thermomechanical model of recrystallization of tungsten for magnetic fusion applications being developed by the Marian Group at UCLA.

  13. Ignition Delay Studies on Hypergolic Fuel Grains

    Directory of Open Access Journals (Sweden)

    S. R. Jain

    1988-07-01

    Full Text Available The ignition delays of several solid hypergolic fuel compositions, casted using various polymeric binders, or as melts, have been determined with fuming nitric acid as oxidizer. The ignition delays of various hypergolic fuel compositions increase drasticaliy on casting with binders like. carboxyl or hydroxyl termninated polybutadiene. Fuel grains cast using some newly syhthesised epoxy  resins with other ingrcdients, such as curing agent, magnesium powder and fuel, have short ignition delays of the order of 200 ms, and also good mechanical strength. Increasing the amount of binder in the composition retards the hypergolicity of the rain. Similar studies have been made on melt-cast systems using low melting hypergolic fuels for casting fuel powders. The ignition delays of the melt-cast grains, are longer than those determined taking the composition in the powder form. The effect of highly hypergolic additives, and metal powders, on the ignition delay of the cast compositions has been determined. Grains having good mechanical strength and short ignition delays have been obtained by optimising the fuel grain composition.

  14. Molecular hydrogen formation on grain surfaces

    CERN Document Server

    Cazaux, S; Tielens, A G G M; Le Bourlot, J; Walmsley, M C

    2005-01-01

    We reconsider H2 formation on grain surfaces. We develop a rate equation model which takes into account the presence of both physisorbed and chemisorbed sites on the surface, including quantum mechanical tunnelling and thermal diffusion. In this study, we took into consideration the uncertainties on the characteristics of graphitic surfaces. We calculate the H2 formation efficiency with the Langmuir Hinshelwood and Eley Rideal mechanisms, and discuss the importance of these mechanisms for a wide range of grain and gas temperatures. We also develop a Monte Carlo simulation to calculate the H2 formation efficiency and compare the results to our rate equation models. Our results are the following: (1) Depending on the barrier against chemisorption, we predict the efficiency of H2 formation for a wide range of grain and gas temperatures. (2) The Eley-Rideal mechanism has an impact on the H2 formation efficiency at high grain and gas temperatures. (3) The fact that we consider chemisorption in our model makes the ...

  15. Analysis of Grain Boundary Character in a Fine-Grained Nickel-Based Superalloy 718

    Science.gov (United States)

    Araujo, L. S.; dos Santos, D. S.; Godet, S.; Dille, J.; Pinto, A. L.; de Almeida, L. H.

    2014-11-01

    In the current work, sheets of superalloy 718 were processed via thermomechanical route by hot and cold rolling, followed by annealing below the δ phase solvus temperature and precipitation hardening to optimum strength. Grain boundary character distribution throughout the processing was mapped via EBSD and its evolution discussed. The results show that it is possible to process the alloy to a fine grain size obtaining concomitantly a considerably high proportion of special boundaries Σ3, Σ9, and Σ27. The precipitation of δ phase presented a strong grain refining role, without significantly impairing the twinning mechanism and, consequently, the Σ3, Σ9, and Σ27 boundary formations.

  16. Surface grain coarsening and surface softening during machining of ultra-fine grained titanium

    Directory of Open Access Journals (Sweden)

    Symonova A.A.

    2012-01-01

    Full Text Available Experiments are run to show that different machining conditions applied to ultra-fine grained pure titanium lead to different levels of grain coarsening and softening near the machined surface. Under “hard” machining conditions the upper 40 microns of the machined surface are altered with a decreased microhardness. The experimental results are reasonably reproduced by model calculations. Expanding the parameter field of the model calculations, the surface coarsening diagram and the surface softening diagram due to machining are presented, showing the region of technological parameters, under which neither grain coarsening nor softening takes place along the machined surface.

  17. Grain growth by Ordered Coalescence of crystallites in Ceramics : Grain Growth Mechanisms, Microstructure Evolution and Sintering

    OpenAIRE

    Hu, Jianfeng

    2013-01-01

    Grain growth and densification process play the two most crucial roles on the microstructure evolution and the achieved performances during sintering of ceramics. In this thesis, the grain growth of SrTiO3, BaTiO3-SrTiO3 solid solutions and Si3N4 ceramics during spark plasma sintering (SPS) were investigated by electron microscopy. SrTiO3 ceramics starting from nanopowders were fabricated by SPS. A novel grain growth mechanism was discovered and named as ordered coalescence (OC) of nanocrysta...

  18. Grain legume protein quality: a hot subject

    Directory of Open Access Journals (Sweden)

    Vaz Patto, Maria Carlota

    2016-06-01

    Full Text Available Grain legumes, also called pulses, play a key role in the nutritional improvement of food and feed. These legumes are important sources of protein as well as other nutritional compounds. Today, protein is one of the most sought after ingredients in the market and grain legumes represent one of the most sustainable protein sources. However, not all grain legume proteins are nutritionally equal. Their quality varies and depends on their amino acid composition and digestibility. In this article, we review concepts related to grain legume protein quality and discuss challenges regarding their genetic improvement. A comprehensive database of grain legume amino acid profiles and protein digestibility is needed to address the matter of protein quality in grain legume breeding. This database will be enhanced by quantitative information on digestibility-reducing bioactive compounds and the development of reliable screening tools. The achievement of higher protein quality grain legume varieties, better adjusted to animal and human requirements, will cut dietary protein content, associated costs and nitrogen excretion, thus reducing the environmental impact.Las leguminosas grano tienen un alto potencial en alimentación humana y animal siendo una importante fuente de proteínas así como de otros compuestos beneficiosos para la nutrición y salud. La proteína es uno de los ingredientes más demandados y las leguminosas grano son una delas fuentes más sostenible de proteína. Sin embargo, no todas las leguminosas grano son igual de nutritivas, variando la calidad con la composición de aminoácidos y su digestibilidad. En este artículo revisaremos los conceptos de calidad de la proteína y discutiremos las posibilidades de mejora genética. Para abordar con éxito la mejora de la calidad de la proteína será de gran ayuda disponer de bases de datos con los perfiles de aminoácidos y de digestibilidad, así como de información cuantitativa sobre los

  19. Paleowattmeters: A scaling relation for dynamically recrystallized grain size

    Science.gov (United States)

    Austin, Nicholas J.; Evans, Brian

    2007-04-01

    During dislocation creep, mineral grains often evolve to a stable size, dictated by the deformation conditions. We suggest that grain-size evolution during deformation is determined by the rate of mechanical work. Provided that other elements of microstructure have achieved steady state and that the dissipation rate is roughly constant, then changes in internal energy will be proportional to changes in grain-boundary area. If normal grain-growth and dynamic grain-size reduction occur simultaneously, then the steady-state grain size is determined by the balance of those rates. A scaling model using these assumptions and published grain-growth and mechanical relations matches stress grain-size relations for quartz and olivine rocks with no fitting. For marbles, the model also explains scatter not rationalized by assuming that recrystallized grain size is a function of stress alone. When extrapolated to conditions typical for natural mylonites, the model is consistent with field constraints on stresses and strain rates.

  20. The Evolution of the Whole Grain Partnership in Denmark

    DEFF Research Database (Denmark)

    Greve, Carsten; Neess, Rikke Iben

    products. The Whole Grain Partnership is a campaign organization supported by 35 partners from government, health NGOs and the food industry. A public‐private partnership holds much promise and presents an exciting opportunity to increase whole grain intake for the benefit of public health. Before......This paper is about the evolution of the Whole Grain Partnership in Denmark. The partnership’s objective is to increase public health by encouraging Danes to eat more whole grain. The partnership also provides a business opportunity for the food industry to expand the market for whole grain...... the Danish Whole Grain Partnership was established in January 2008, Danes ate on average only 36 grams of whole grain per day per 10MJ (mega joules). Today, Danes eat on average 63 grams of whole grain per day per 10MJ. 30% of the population now eats the recommended intake of 75 grams of whole grain per day...

  1. Impact of Industrialization on Grain Consumption and Countermeasures

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    This paper analyzes the impact of industrialization on grain consumption from growth of residents’ income and change of diet structure,expansion of size of population,and development of new biomass energy industry.The economic growth in the course of industrialization promotes growth of residents’ income,changes residents’ diet structure;industrialization leads to rural urbanization and rise of urban residents;industrial development brings about grain demand of biomass energy.All of these greatly increase demand of grain consumption.On the basis of these situations,it presents following countermeasures to guarantee grain consumption demand in the course of industrialization:heighten awareness to fully realize the significance of rapid development of industrialization to grain security;control population growth and improve grain conversion ratio;strengthen grain-saving construction and advocate moderate consumption;develop non-grain biomass energy in many channels to guarantee grain security.

  2. Systematic Comparisons of Orthologous Selenocysteine Methyltransferase and Homocysteine Methyltransferase Genes from Seven Monocots Species

    Directory of Open Access Journals (Sweden)

    De-yong ZHAO

    2015-06-01

    Full Text Available Identifying and manipulating genes underlying selenium metabolism could be helpful for increasing selenium content in crop grain, which is an important way to overcome diseases resulted from selenium deficiency. A reciprocal smallest distance algorithm (RSD approach was applied using two experimentally confirmed Homocysteine S-Methyltransferases genes (HMT1 and HMT2 and a putative Selenocysteine Methyltransferase (SMT from dicots plant Arabidopsis thaliana, to explore their orthologs in seven sequenced diploid monocot species: Oryza sativa, Zea mays, Sorghum bicolor, Brachypodium distachyon, Hordeum vulgare, Aegilops tauschii (the D-genome donor of common wheat and Triticum urartu (the A-genome donor of common wheat. HMT1 was apparently diverged from HMT2 and most of SMT orthologs were the same with that of HMT2 in this study, leading to the hypothesis that SMT and HMT originate from one common ancestor gene. Identifying orthologs provide candidates for further experimental confirmation; also it could be helpful in designing primers to clone SMT or HMT orthologs in other crops.

  3. Whole grains and health: perspective for Asian Indians.

    Science.gov (United States)

    Misra, A; Rastogi, Kavita; Joshi, Shashank R

    2009-02-01

    Grains are a part of human diet for about 10,000 years. Grains are the most important food source of Indian population, due to this carbohydrate consumption constitute approx. 60-70% of total food intake. Variety of grains are available in India, and different grains form staple diets of people in different part of the country. Whole grains are now recognized as an important source of fiber and other nutrients like trace minerals a vitamins. Grains have shown to have a role in prevention and reducing the risk of type 2 diabetes, coronary heart disease, cancer and obesity.

  4. Analysis of Theoretical Basis of Direct Subsidies for Grain Production

    Institute of Scientific and Technical Information of China (English)

    Shengping; SHI; Xiaorong; LUO; Hongjing; LI

    2014-01-01

    Financial distribution to compensate grain production reflects governmental macro-control on grain production and supply. With the reference of agricultural basic theory,agricultural multi-function theory,economic externality theory,public finance and other theories,this article points out that direct subsidies for grain production is reasonable and necessary with six main theoretical basis,namely fundamentality,multi-function,positive externality of grain production,particularity of grain supply and demand,grain safety being closely linked with national security and basic function of service-oriented government.

  5. Superconductivity of individual grains and inter-grain boundaries for polycrystalline FeSrYCuO

    Science.gov (United States)

    Yamaguchi, K.; Hata, Y.; Mochiku, T.; Yasuoka, H.

    2013-04-01

    Polycrystalline FeSrYCuO was synthesized and its transport and magnetic properties were studied. Diamagnetism was observed below 60 K. Zero resistivity was observed below 38 K under zero magnetic field and below 10 K under 160 kOe. A two-step transition was observed in resistivity measurement due to the superconductivity in individual grains and across inter-grain boundaries. The critical current density in individual grains, Jcintra, at 2 K under 1 kOe was deduced 3.4 × 105 A/cm2 from the Bean model. In contrast, the critical current density in inter-grain boundaries, Jcinter, at 2 K was 1.7 A/cm2 in voltage-current measurement. The two-step transition seems to result from the large difference between Jcintra and Jcinter.

  6. Reproductive performance of reindeer fed all-grain and hay-grain rations

    Directory of Open Access Journals (Sweden)

    J. M. Blanchard

    1986-06-01

    Full Text Available Reproductive performance of grain-fed reindeer {Rangifer tarandus was evaluated over a 2-year period. Groups of pregnant reindeer were fed one of three rations, (1 100% whole-grain barley, (2 98.9% whole-grain barley and 1.2% mineral and trace element supplement, and (3 70% whole-grain barley and 30% finely-chopped bluegrass hay. Reindeer fed unsupplemented whole-barley failed to produce a single live calf. The addition of mineral and trace element supplement to the ration did not result in any significant improvement in reproductive performance. Eighty-five percent of the reindeer consuming unsupplemented and supplemented all-barley rations became pregnant; however, 76% of the pregnancies resulted in stillborn calves. One-hundred percent of the cows maintained on the grain/hay ration produced live calves. We speculate that reproductive failure in reindeer cows maintained on all-grain rations is most likely a result of a diet induced disfunction in maternal rumen and/or carbohydrate metabolism rather than a micro-nutrient deficiency. More research is neeeded to determine which metabolic pathways are affected.

  7. Grain-boundary structures in hexagonal materials: Coincident and near coincident grain boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, D. (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Materials Science and Engineering)

    1994-07-01

    Embedded atom method (EAM) simulations of the structure of grain boundaries in hexagonal metal, are presented. The simulations use recently developed interatomic potentials for Ti and Co. Structures were calculated for various symmetrical tilt boundaries with the [1,100] tilt axis. The structures obtained for both metals are very similar. The energies for the Co boundaries are higher than those for Ti by a factor of 2. The structural unit model was applied to the computed grain-boundary structures in these hexagonal materials. As in cubic materials, the structural unit model can describe a series of symmetrical tilt coincident boundaries. In addition, when the coincidence ratio in the grain-boundary plane varies with the c/a ratio, a structural unit-type model can describe the variation of grain-boundary structure with c/a ratio. This model is adequate for describing series of symmetrical tilt boundaries with the grain-boundary plane oriented perpendicular to a fixed crystallographic direction and varying c/a ratios. For the structures of the so-called near coincident boundaries that appear in these materials, it was concluded that near coincident boundaries behave similarly to exact coincidence boundaries if there is a coincident periodic structure in the grain-boundary plane. This may occur even without a three-dimensional (3-D) coincident site lattice.

  8. Genetic dissection of grain size and grain number trade-offs in CIMMYT wheat germplasm.

    Directory of Open Access Journals (Sweden)

    Simon Griffiths

    Full Text Available Grain weight (GW and number per unit area of land (GN are the primary components of grain yield in wheat. In segregating populations both yield components often show a negative correlation among themselves. Here we use a recombinant doubled haploid population of 105 individuals developed from the CIMMYT varieties Weebill and Bacanora to understand the relative contribution of these components to grain yield and their interaction with each other. Weebill was chosen for its high GW and Bacanora for high GN. The population was phenotyped in Mexico, Argentina, Chile and the UK. Two loci influencing grain yield were indicated on 1B and 7B after QTL analysis. Weebill contributed the increasing alleles. The 1B effect, which is probably caused by to the 1BL.1RS rye introgression in Bacanora, was a result of increased GN, whereas, the 7B QTL controls GW. We concluded that increased in GW from Weebill 7B allele is not accompanied by a significant reduction in grain number. The extent of the GW and GN trade-off is reduced. This makes this locus an attractive target for marker assisted selection to develop high yielding bold grain varieties like Weebill. AMMI analysis was used to show that the 7B Weebill allele appears to contribute to yield stability.

  9. Development of two-stage grain grinder

    Directory of Open Access Journals (Sweden)

    V. N. Trubnikov

    2016-01-01

    Full Text Available The most important task in the development of the diet of farm animals feeding is a selection of the most balanced in its composition and most nutritious feeds, which are safe and meet all the necessary requirements at the same time. To evaluate the productive value of feeds and their effectiveness the rate of food productive action η was proposed. This ratio reflects the productive part of the total value of the exchange energy of the daily feed ration and is an essential criterion of the feed quality indicators. In the feed rations of animals the most expensive, but energy-rich feed is a mixed fodder, a mixture of grinded seeds of agricultural crops and protein, mineral and vitamin additives. In the diet for its nutritional value, this feed product is for cattle – 50, pigs – 60… 100 and birds – 100%. The basic operation in the production of mixed fodder is seeds grinding, i.e. their destruction under the influence of external forces, exceeding the forces of molecular adhesion of the grains particles. To grind the grain different ways are used: chopping, grinding, impact «in flight», crushing, etc. In the production of mixed fodder on the existing production equipment, there is the problem of getting the grain mixed fodder the necessary degree of grinding and uniform in its particle size distribution at the same time. When receiving too coarse grinding there is a problem of difficult digestibility of mixed fodder by farm animals. Moreover grinding process is accompanied by a high energy consumption. Grain grinder, the principle of which is based on the implementation of two ways of grinding grain: splitting and impact «in flight» is proposed. The proposed constructive solutions allow to obtain a high-performance technical means for crushing seeds of crops, as well as reduce energy costs that arise during the course of the process of obtaining of mixed fodder. The methodology justification of degree of grain grinding by

  10. Shattering and coagulation of dust grains in interstellar turbulence

    CERN Document Server

    Hirashita, Hiroyuki

    2008-01-01

    We investigate shattering and coagulation of dust grains in turbulent interstellar medium (ISM). The typical velocity of dust grain as a function of grain size has been calculated for various ISM phases based on a theory of grain dynamics in compressible magnetohydrodynamic turbulence. In this paper, we develop a scheme of grain shattering and coagulation and apply it to turbulent ISM by using the grain velocities predicted by the above turbulence theory. Since large grains tend to acquire large velocity dispersions as shown by earlier studies, large grains tend to be shattered. Large shattering effects are indeed seen in warm ionized medium (WIM) within a few Myr for grains with radius $a\\ga 10^{-6}$ cm. We also show that shattering in warm neutral medium (WNM) can limit the largest grain size in ISM ($a\\sim 2\\times 10^{-5} \\mathrm{cm}$). On the other hand, coagulation tends to modify small grains since it only occurs when the grain velocity is small enough. Coagulation significantly modifies the grain size ...

  11. Modulation of phytochrome signaling networks for improved biomass accumulation using a bioenergy crop model

    Energy Technology Data Exchange (ETDEWEB)

    Mockler, Todd C. [Donald Danforth Plant Science Center, Saint Louis, MO (United States)

    2016-11-07

    Plant growth and development, including stem elongation, flowering time, and shade-avoidance habits, are affected by wavelength composition (i.e., light quality) of the light environment. the molecular mechanisms underlying light perception and signaling pathways in plants have been best characterized in Arabidopsis thaliana where dozens of genes have been implicated in converging, complementary, and antagonistic pathways communicating light quality cues perceived by the phytochrome (red/far-red) cryptochrome (blue) and phototropin (blue) photorecptors. Light perception and signaling have been studied in grasses, including rice and sorghum but in much less detail than in Arabidopsis. During the course of the Mocker lab's DOE-funded wrok generating a gene expression atlas in Brachypodium distachyon we observed that Brachypodium plants grown in continuous monochromatic red light or continuous white light enriched in far-red light accumulated significantly more biomass and exhibited significantly greater seed yield than plants grown in monochromatic blue light or white light. This phenomenon was also observed in two other grasses, switchgrass and rice. We will systematically manipulate the expression of genes predicted to function in Brachypodium phytochrome signaling and assess the phenotypic consequences in transgenic Brachypodium plants in terms of morphology, stature, biomass accumulation, and cell wall composition. We will also interrogate direct interactions between candidate phytochrome signaling transcription factors and target promoters using a high-throughput yeast one-hybrid system. Brachypodium distachyon has emerged as a model grass species and is closely related to candidate feedstock crops for bioethanol production. Identification of genes capable of modifying growth characteristics of Brachypodium, when misexpressed, in particular increasing biomass accumulation, by modulating photoreceptor signaling will provide valuable candidates for

  12. Coarse-grained Modeling of DNA Curvature

    CERN Document Server

    Freeman, Gordon S; Lequieu, Joshua P; Whitmer, Jonathan K; de Pablo, Juan J

    2014-01-01

    Modeling of DNA-protein interactions is a complex process involving many important time and length scales. This can be facilitated through the use of coarse-grained models which reduce the number of degrees of freedom and allow efficient exploration of binding configurations. It is known that the local structure of DNA can significantly affect its protein-binding properties (i.e. intrinsic curvature in DNA-histone complexes). In a step towards comprehensive DNA-protein modeling, we expand the 3SPN.2 coarse-grained model to include intrinsic shape, and validate the refined model against experimental data including melting temperature, local flexibility, persistence length, and minor groove width profile.

  13. Argyrophilic grain disease: An underestimated tauopathy

    Directory of Open Access Journals (Sweden)

    Roberta Diehl Rodriguez

    Full Text Available Argyrophilic grain disease (AGD is an under-recognized, distinct, highly frequent sporadic tauopathy, with a prevalence reaching 31.3% in centenarians. The most common AGD manifestation is slowly progressive amnestic mild cognitive impairment, accompanied by a high prevalence of neuropsychiatric symptoms. AGD diagnosis can only be achieved postmortem based on the finding of its three main pathologic features: argyrophilic grains, oligodendrocytic coiled bodies and neuronal pretangles. AGD is frequently seen together with Alzheimer's disease-type pathology or in association with other neurodegenerative diseases. Recent studies suggest that AGD may be a defense mechanism against the spread of other neuropathological entities, particularly Alzheimer's disease. This review aims to provide an in-depth overview of the current understanding on AGD.

  14. Grain yield stability of early maize genotypes

    Directory of Open Access Journals (Sweden)

    Chitra Bahadur Kunwar

    2016-12-01

    Full Text Available The objective of this study was to estimate grain yield stability of early maize genotypes. Five early maize genotypes namely Pool-17, Arun1EV, Arun-4, Arun-2 and Farmer’s variety were evaluated using Randomized Complete Block Design along with three replications at four different locations namely Rampur, Rajahar, Pakhribas and Kabre districts of Nepal during summer seasons of three consecutive years from 2010 to 2012 under farmer’s fields. Genotype and genotype × environment (GGE biplot was used to identify superior genotype for grain yield and stability pattern. The genotypes Arun-1 EV and Arun-4 were better adapted for Kabre and Pakhribas where as pool-17 for Rajahar environments. The overall findings showed that Arun-1EV was more stable followed by Arun-2 therefore these two varieties can be recommended to farmers for cultivation in both environments.

  15. STUDY ON GRAIN MARKET IN THE WORLD

    Directory of Open Access Journals (Sweden)

    Elena COFAS

    2013-01-01

    Full Text Available In the global economy, the market occupies a representative place because the grain is grown on a large area and it is important both to ensure food security and safety, but also for animal feed. In order to accomplish this study we have used certain indicators, of which the most representative are: acreage, production obtained, yield per hectare, food consumption, imports, exports and last but not least the price. World market of cereals has increased in the past decade due to increased consumption of cereals, especially in less developed countries economically. World grain market evolution in the analyzed period was disrupted on one side by the global economic crisis and on the other side by bad weather changes that occur on a global scale and have had a negative impact on acreage, production achieved, prices etc. According to forecasts the global market for cereals is expected to increase trade with cerereale, while diminishing stocks.

  16. Economic efficiency of the maize grain

    Directory of Open Access Journals (Sweden)

    Ana Mariana Dincu

    2014-11-01

    Full Text Available In this work, was calculated and the level of profitability for several levels of production for grain maize cultivation. We chose corn because it is one of the most important forage crops, we could say even the largest, occupying third place among cultivated plants worldwide. Along with wheat and barley, the food is the biggest part of the population in the world, directly or converted to animal products. Maize can be used in animal feed in various forms. The most used is corn grain, which is characterized by a very high nutritional value, this product is properly regarded as a feed concentrate. Culture of maize have been designed two levels of production: 4000 kg / ha and 6000 kg / ha.

  17. Fatigue In Tension Perpendicular to the Grain

    DEFF Research Database (Denmark)

    Clorius, Christian Odin; Pedersen, Martin Uhre; Hoffmeyer, Preben;

    2004-01-01

    mechanism and a mechanism connected to damage introduced in the loading sequences. The purpose of the present study is to disentangle the effect of duration of load from the effect of load oscillation in fatigue in tension perpendicular to the grain. Fatigue experiments are made on small specimens...... and on dowel type joints with slotted in steel plates. In series of ten, the small specimens are taken to fatigue failure in uniform tension at square wave shaped load cycles at 0.01 Hz and 0.1 Hz. In arder to test the predictive validity of the result from the small tension specimens, fatigue experiments......Traditionally fatigue resistance is quantified as number of cycles to failure at a given stress level. A previous study by the authors showed that fatigue in compression parallel to the grain is governed partly by duration of load and partly by an effect of loading, i.e. a combination of a creep...

  18. Fatigue in tension perpendicular to the grain

    DEFF Research Database (Denmark)

    Clorius, Christian Odin; Pedersen, Martin Bo Uhre; Hoffmeyer, Preben;

    1999-01-01

    mechanism and a mechanism connected to damage introduce in the loading sequences. The purpose of the present study is to disentangle the effect of duration of load from the effect of load oscillation in fatigue in tension perpendicular to the grain. Fatigue experiments are made on small specimens...... and on dowel type joints with slotted in steel plates. In series of ten, the small specimens are taken to fatigue failure in uniform tension at square wave shaped load cycles at 0.01 Hz and 0.1 Hz. In order to test the predictive validity of the result from the small tension specimens, fatigue experiments......Traditinally fatigue resistance is quantified as number of cycles to failure at a given stress level. A previous study by the authors showed that fatigue in compression parallel to the grain is governed partly by duration of load and partly by an effect of loading, i.e. a combination of a creep...

  19. Composite grains: Application to circumstellar dust

    Directory of Open Access Journals (Sweden)

    D. B. Vaidya

    2011-09-01

    Full Text Available Using the discrete dipole approximation (DDA we calculate the absorption efficiency of the composite grain, made up of a host silicate spheroid and inclusions of graphite, in the spectral region 5.0-25.0μm. We study the absorption as a function of the voulume fraction of the inclusions. In particular, we study the variation in the 10.0μm and 18.0μm emission features with the volume fraction of the inclusions. Using the extinction efficiencies, of the composite grains we calculate the infrared fluxes at several dust temperatures and compare the model curves with the observed infrared emission curves (IRAS-LRS, obtained for circumstellar dust shells around oxygen rich M-type stars.

  20. Breakdown of Superconductivity in Small Metallic Grains

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhi-Qian; ZHENG Ren-Rong

    2000-01-01

    Superconductivity in small metallic grains is carefully checked as their size is decreased to a few nm when the average level spacing d could be compared with the bulk gap Δ. Using random matrix theory to the mean field, we find that the average theoretical values of the critical level spacing for both odd and even numbers of electrons and the transition temperature Tc in three Gauss ensembles are quite different for those from the model of uniformly spaced levels. For Sz = 1/2, as grain size is reduced, the transition temperature or the granular gap decreases monotonously, and the relation 2△(0)/kB Tc ≤ 3.53 always exists.

  1. CHP plant reduces grain whisky costs

    Energy Technology Data Exchange (ETDEWEB)

    Forrester, R.

    1989-04-01

    Scottish Grain Distillers Limited operate one of the largest grain whisky spirit production units in Scotland at Port Dundas Distillery, Glasgow. In 1972, a treatment plant for the distillery residues was installed. This was a major user of steam and fuelled by oil. In 1983, prompted by spiralling oil price rises, changes in the plant were initiated resulting in a significant move away from steam to electricity as the main source of energy and replacing oil by gas as the boiler fuel. To further improve the economics, an on-site gas turbine combined heat and power (CHP) system has been installed, any excess power being exported to the national grid. Estimated savings achieved by the CHP system point to a payback of 5.2 years on the gross investment capital. (U.K.).

  2. Grain boundary and triple junction diffusion in nanocrystalline copper

    Energy Technology Data Exchange (ETDEWEB)

    Wegner, M., E-mail: m.wegner@uni-muenster.de; Leuthold, J.; Peterlechner, M.; Divinski, S. V., E-mail: divin@uni-muenster.de [Institut für Materialphysik, Universität Münster, Wilhelm-Klemm-Straße 10, D-48149, Münster (Germany); Song, X., E-mail: xysong@bjut.edu.cn [College of Materials Science and Engineering, Beijing University of Technology, 100124 Beijing (China); Wilde, G. [Institut für Materialphysik, Universität Münster, Wilhelm-Klemm-Straße 10, D-48149, Münster (Germany); Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering, Shanghai University, 200444 Shanghai (China)

    2014-09-07

    Grain boundary and triple junction diffusion in nanocrystalline Cu samples with grain sizes, 〈d〉, of ∼35 and ∼44 nm produced by spark plasma sintering were investigated by the radiotracer method using the {sup 63}Ni isotope. The measured diffusivities, D{sub eff}, are comparable with those determined previously for Ni grain boundary diffusion in well-annealed, high purity, coarse grained, polycrystalline copper, substantiating the absence of a grain size effect on the kinetic properties of grain boundaries in a nanocrystalline material at grain sizes d ≥ 35 nm. Simultaneously, the analysis predicts that if triple junction diffusion of Ni in Cu is enhanced with respect to the corresponding grain boundary diffusion rate, it is still less than 500⋅D{sub gb} within the temperature interval from 420 K to 470 K.

  3. Longitudinal Decline in Lung Function Measurements among Saskatchewan Grain Workers

    Directory of Open Access Journals (Sweden)

    Punam Pahwa

    2003-01-01

    Full Text Available OBJECTIVE: To evaluate the relationship between the long term effects of grain dust and decline in lung function among grain elevator workers in Saskatchewan, studied over a 15-year period.

  4. "Eat Fresh Vegetables, Fruit, and Whole Grain Products"

    Science.gov (United States)

    ... on. Feature: Diverticulitis "Eat fresh vegetables, fruit, and whole grain products." Past Issues / Winter 2010 Table of Contents ... once again eat fresh vegetables and fruit and whole grain products. My two episodes of diverticulitis were not ...

  5. Can Whole-Grain Foods Lower Blood Pressure?

    Science.gov (United States)

    ... Conditions High blood pressure (hypertension) Can eating more whole-grain foods help lower my blood pressure? Answers from ... G. Sheps, M.D. It might. Eating more whole-grain foods on a regular basis may help reduce ...

  6. Understanding Solidification Based Grain Refinement in Steels

    Science.gov (United States)

    2014-12-18

    interatomic spacing along [uvw]s, and 0 = the angle between the [uvwjjand [uvw]n.^’ Work on the grain refinement of aluminum and magnesium alloys has found...chemistry ternary plot from ASPEX system. The author found some evidence of reactions occurring with some rare earth oxide or sulfide inclusions and... sulfide .^^"^^ Another approach would be to react a sample of misch metal or rare earth silicide at elevated temperatures to form the desired oxide or

  7. Genetic engineering for high methionine grain legumes.

    Science.gov (United States)

    Müntz, K; Christov, V; Saalbach, G; Saalbach, I; Waddell, D; Pickardt, T; Schieder, O; Wüstenhagen, T

    1998-08-01

    Methionine (Met) is the primary limiting essential amino acid in grain legumes. The imbalance in amino acid composition restricts their biological value (BV) to 55 to 75% of that of animal protein. So far improvement of the BV could not be achieved by conventional breeding. Therefore, genetic engineering was employed by several laboratories to resolve the problem. Three strategies have been followed. A) Engineering for increased free Met levels; B) engineering of endogenous storage proteins with increased numbers of Met residues; C) transfer of foreign genes encoding Met-rich proteins, e.g. the Brazil nut 2S albumin (BNA) and its homologue from sunflower, into grain legumes. The latter strategy turned out to be most promising. In all cases the gene was put under the control of a developmentally regulated seed specific promoter and transferred into grain legumes using the bacterial Agrobacterium tumefaciens-system. Integration into and copy numbers in the plant genome as well as Mendelian inheritance and gene dosage effects were verified. After correct precursor processing the mature 2S albumin was intracellularly deposited in protein bodies which are part of the vacuolar compartment. The foreign protein amounted to 5 to 10% of the total seed protein in the best transgenic lines of narbon bean (Vicia narbonensis L., used in the authors' laboratories), lupins (Lupinus angustifolius L., used in CSIRO, Australia), and soybean (Glycine max (L.) Merr., used by Pioneer Hi-Bred, Inc., USA). In the narbon bean the increase of Met was directly related to the amount of 2S albumin in the transgenic seeds, but in soybean it remained below the theoretically expected value. Nevertheless, trangenic soybean reached 100%, whereas narbon bean and lupins reached approximately 80% of the FAO-standard for nutritionally balanced food proteins. These results document that the Met problem of grain legumes can be resolved by genetic engineering.

  8. Soaring Grain Prices Raise Global Concerns

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ rain prices often dominate all other product prices, and an increase in their price is usually considered as a prelude to inflation. The three fairly serious inflations, in 1985, 1988-1989, and 1993-1995respectively, were all preceded by grain price hikes. Furthermore, the money supply surged in the preceding year or during the same year in which these inflations occurred. This year has witnessed the same symptoms.

  9. Coarse graining flow of spin foam intertwiners

    Science.gov (United States)

    Dittrich, Bianca; Schnetter, Erik; Seth, Cameron J.; Steinhaus, Sebastian

    2016-12-01

    Simplicity constraints play a crucial role in the construction of spin foam models, yet their effective behavior on larger scales is scarcely explored. In this article we introduce intertwiner and spin net models for the quantum group SU (2 )k×SU (2 )k, which implement the simplicity constraints analogous to four-dimensional Euclidean spin foam models, namely the Barrett-Crane (BC) and the Engle-Pereira-Rovelli-Livine/Freidel-Krasnov (EPRL/FK) model. These models are numerically coarse grained via tensor network renormalization, allowing us to trace the flow of simplicity constraints to larger scales. In order to perform these simulations we have substantially adapted tensor network algorithms, which we discuss in detail as they can be of use in other contexts. The BC and the EPRL/FK model behave very differently under coarse graining: While the unique BC intertwiner model is a fixed point and therefore constitutes a two-dimensional topological phase, BC spin net models flow away from the initial simplicity constraints and converge to several different topological phases. Most of these phases correspond to decoupling spin foam vertices; however we find also a new phase in which this is not the case, and in which a nontrivial version of the simplicity constraints holds. The coarse graining flow of the BC spin net models indicates furthermore that the transitions between these phases are not of second order. The EPRL/FK model by contrast reveals a far more intricate and complex dynamics. We observe an immediate flow away from the original simplicity constraints; however, with the truncation employed here, the models generically do not converge to a fixed point. The results show that the imposition of simplicity constraints can indeed lead to interesting and also very complex dynamics. Thus we need to further develop coarse graining tools to efficiently study the large scale behavior of spin foam models, in particular for the EPRL/FK model.

  10. Combining abilities of silage maize grain yield

    Directory of Open Access Journals (Sweden)

    Živanović Tomislav

    2005-01-01

    Full Text Available The aim of the present study was to evaluate the following parameters of maize grain yield: variability of inbred lines and their diallel hybrids superior-parent heterosis and general and special combining abilities. According to obtained results of the two-year study, it can be concluded that variability of this trait is significantly affected by a genotype, year and their interaction. As expected, hybrids had higher average grain yields than inbreds due to the depression of this trait that occurs in inbreds during inbreeding. The highest average value of heterosis for gain yield was detected in the hybrid ZPLB405 x ZPLB406 (123.0% and 178.1% in 1997 and 1998, respectively. The estimation of combining abilities was done on the basis of diallel hybrids after the method established by Griffing, 1956 (method II, mathematical model I. The analysis of variance of combining ability for grain yield indicated highly significant values of GCA and SCA for the observed trait in both study years. Grain yield inheritance was more affected by non-additive genes (dominance and epistasis as indicated by the GCA to SCA ratio that was smaller than unity. The inbreds ZPLB401 and ZPLB406 had high GCA effects, while the hybrid combinations ZPLB40Î x ZPLB402, ZPLB401 x ZPLB403, ZPLB401 x ZPLB405, ZPLB402 x ZPLB406, ZPLB403 x ZPLB406, ZPLB404 x ZPLB406, ZPLB405 x ZPLB406 had high SCA effects in both study years. These hybrid combinations include one parent with high GCA effects and other with low GCA effects. Furthermore, there are combinations ZPLB402 x ZPLB405, ZPLB403 x ZPLB405 and ZPLB404 x ZPLB405 with significant SCA effects that include parents with low GCA effects. This is probably the result of the additive type (additive x additive of interaction between parents.

  11. Statistic Ensemble Theory of Small Superconducting Grains

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhi-Qian; ZHENG Ren-Rong

    2001-01-01

    We apply the random matrix theory to small metallic grains in different spin states of S = 0, 1/2, 1, 3/2, 2, 5/2, .., and find that there exist theoretical critical level spacings de at which the superconductivity would breakdown. We also find that the higher the spin state, the smaller the critical level spacing, and for the state of S = 0superconducting enhancement actually exists.

  12. Feed grain improvement through biopreservation and bioprocessing

    OpenAIRE

    Olstorpe, Matilda

    2008-01-01

    Fermentation is an environmentally friendly method to improve feed quality. Fermented liquid feed and airtight stored moist crimped cereal grain systems that are of increasing importance in agricultural practice were studied. Both rely on spontaneous microbial developments with poorly understood population dynamics, resulting in unpredictable final quality. Temperature, fermentation time and ingredients affected final properties of the feed. Molecular-based species identification showed that ...

  13. Regulation of aleurone development in cereal grains.

    Science.gov (United States)

    Becraft, Philip W; Yi, Gibum

    2011-03-01

    The aleurone layer of cereal grains is important biologically as well as nutritionally and economically. Here, current knowledge on the regulation of aleurone development is reviewed. Recent reports suggest that the control of aleurone development is more complex than earlier models portrayed. Multiple levels of genetic regulation control aleurone cell fate, differentiation, and organization. The hormones auxin and cytokinin can also influence aleurone development. New technical advances promise to facilitate future progress.

  14. Grain Size Dependence of Exchange-Coupling Interaction between Magnetically Soft-Hard Grains and Effective Anisotropy

    Institute of Scientific and Technical Information of China (English)

    韩广兵; 高汝伟; 傅爽; 刘汉强; 冯维存; 陈伟

    2004-01-01

    Taking α-Fe and Nd2Fe14B grains as example, the grain size dependence of the exchange-coupling interaction and effective anisotropy and also their variations depending on the ratio of magnetically soft and hard grain sizes, Ds∶ Dh, were investigated. When grain size D>Lex, the grain's anisotropy is the statistic value of the coupled and uncoupled part. The anisotropy constant of uncoupled part is the common value K1 and that of coupled part varies with the distance to the grain surface. The effective anisotropy constant between magnetically soft and hard grains, Keff, can be expressed as the sum of the products of volume fractions for soft and hard grains, respectively, and the corresponding mean anisotropy constants. The calculation results indicate that the exchange-coupling interaction is enhanced with the reduction of grain size, and the effective anisotropy decreases with reducing grain size and increasing ratio of Ds∶ Dh. In order to get high effective anisotropy constant, Keff, in composite magnetically soft-hard grains, the hard grain size should be larger than 30 nm and the soft grain size should be about 10 nm.

  15. Coarse-grained protein molecular dynamics simulations

    Science.gov (United States)

    Derreumaux, Philippe; Mousseau, Normand

    2007-01-01

    A limiting factor in biological science is the time-scale gap between experimental and computational trajectories. At this point, all-atom explicit solvent molecular dynamics (MD) are clearly too expensive to explore long-range protein motions and extract accurate thermodynamics of proteins in isolated or multimeric forms. To reach the appropriate time scale, we must then resort to coarse graining. Here we couple the coarse-grained OPEP model, which has already been used with activated methods, to MD simulations. Two test cases are studied: the stability of three proteins around their experimental structures and the aggregation mechanisms of the Alzheimer's Aβ16-22 peptides. We find that coarse-grained isolated proteins are stable at room temperature within 50ns time scale. Based on two 220ns trajectories starting from disordered chains, we find that four Aβ16-22 peptides can form a three-stranded β sheet. We also demonstrate that the reptation move of one chain over the others, first observed using the activation-relaxation technique, is a kinetically important mechanism during aggregation. These results show that MD-OPEP is a particularly appropriate tool to study qualitatively the dynamics of long biological processes and the thermodynamics of molecular assemblies.

  16. Fungicide and insecticide residues in rice grains

    Directory of Open Access Journals (Sweden)

    Gustavo Mack Teló

    2017-01-01

    Full Text Available The objective of this study was to analyse residues of fungicides and insecticides in rice grains that were subjected to different forms of processing. Field work was conducted during three crop seasons, and fungicides and insecticides were applied at different crop growth stages on the aerial portion of the rice plants. Azoxystrobin, difenoconazole, propiconazole, tebuconazole, and trifloxystrobin fungicides were sprayed only once at the R2 growth stage or twice at the R2 and R4 growth stages; cypermethrin, lambda-cyhalothrin, permethrin, and thiamethoxam insecticides were sprayed at the R2 growth stage; and permethrin was sprayed at 5-day intervals from the R4 growth stage up to one day prior to harvest. Pesticide residues were analysed in uncooked, cooked, parboiled, polished and brown rice grains as well as rice hulls during the three crop seasons, for a total of 1458 samples. The samples were analysed by gas chromatography with electron capture detection (GC-ECD using modified QuEChERS as the extraction method. No fungicide or insecticide residues were detected in rice grain samples; however, azoxystrobin and cypermethrin residues were detected in rice hull samples.

  17. Grain Surface Models and Data for Astrochemistry

    Science.gov (United States)

    Cuppen, H. M.; Walsh, C.; Lamberts, T.; Semenov, D.; Garrod, R. T.; Penteado, E. M.; Ioppolo, S.

    2017-01-01

    The cross-disciplinary field of astrochemistry exists to understand the formation, destruction, and survival of molecules in astrophysical environments. Molecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst. A broad consensus has been reached in the astrochemistry community on how to suitably treat gas-phase processes in models, and also on how to present the necessary reaction data in databases; however, no such consensus has yet been reached for grain-surface processes. A team of {˜}25 experts covering observational, laboratory and theoretical (astro)chemistry met in summer of 2014 at the Lorentz Center in Leiden with the aim to provide solutions for this problem and to review the current state-of-the-art of grain surface models, both in terms of technical implementation into models as well as the most up-to-date information available from experiments and chemical computations. This review builds on the results of this workshop and gives an outlook for future directions.

  18. Dust grains from the heart of supernovae

    CERN Document Server

    Bocchio, M; Schneider, R; Bianchi, S; Limongi, M; Chieffi, A

    2016-01-01

    Dust grains are classically thought to form in the winds of AGB stars. However, nowadays there is increasing evidence for dust formation in SNe. In order to establish the relative importance of these two classes of stellar sources of dust it is important to know what is the fraction of freshly formed dust in SN ejecta that is able to survive the passage of the reverse shock and be injected in the interstellar medium. With this aim, we have developed a new code, GRASH_Rev, that allows to follow the dynamics of dust grains in the shocked SN ejecta and to compute the time evolution of the mass, composition and size distribution of the grains. We consider four well studied SNe in the Milky Way and LMC: SN 1987a, Cas A, the Crab Nebula, and N49. For all the simulated models, we find good agreement with observations. Our study suggests that SN 1987A is too young for the reverse shock to have affected the dust mass. Conversely, in the other three SNe, the reverse shock has already destroyed between 10 and 40% of the...

  19. Multiple age components in individual molybdenite grains

    Science.gov (United States)

    Aleinikoff, John N.; Creaser, Robert A.; Lowers, Heather; Magee, Charles W.; Grauch, Richard I.

    2012-01-01

    Re–Os geochronology of fractions composed of unsized, coarse, and fine molybdenite from a pod of unusual monazite–xenotime gneiss within a granulite facies paragneiss, Hudson Highlands, NY, yielded dates of 950.5 ± 2.5, 953.8 ± 2.6, and 941.2 ± 2.6 Ma, respectively. These dates are not recorded by co-existing zircon, monazite, or xenotime. SEM–BSE imagery of thin sections and separated grains reveals that most molybdenite grains are composed of core and rim plates that are approximately perpendicular. Rim material invaded cores, forming irregular contacts, probably reflecting dissolution/reprecipitation. EPMA and LA-ICP-MS analyses show that cores and rims have different trace element concentrations (for example, cores are relatively enriched in W). On the basis of inclusions of zircon with metamorphic overgrowths, we conclude that molybdenite cores and rims formed after high-grade regional metamorphism. The discovery of cores and rims in individual molybdenite grains is analogous to multi-component U-Pb geochronometers such as zircon, monazite, and titanite; thus, molybdenite should be carefully examined before dating to ensure that the requirement of age homogeneity is fulfilled.

  20. ELECTROSTATICALLY SUPPORTED MIXING OF FINE GRAINED PARTICLES

    Institute of Scientific and Technical Information of China (English)

    K.-E.; Wirth; M.; Linsenbühler

    2005-01-01

    The processing of fine-grained particles with diameters between 1 and 10 microns is difficult due to strong van-der-Waals attraction forces. In order to improve the handling properties, the fine-grained particles, i.e. host-particles,are coated with various nanoparticles, i.e. guest-particles. The mixing of fine-grained powders is influenced by particle-particle interactions. If these forces are distinctively used, both interactive and ordered mixtures can be produced.These particle mixtures consist of composite-particles that have new physical properties. These modified properties d epend strongly on the coating process, the diameter- and mass-relationship of the guest- and the host-particles. The properties of the composite-particles can systematically be adjusted to the requirements of industrial applications. For example, a laboratory bubbling fluidized bed can be used to describe the conveying behavior of the functionalized host-particles. Applications for the functionalized particles are in the pharmaceutical and the powder coating industries,e.g. enhanced dry powder inhalers and thin lacquer films. The present research compares three different mixing/coating processes. The composite-particles are characterized by TEM, SEM and with their fluidization characteristics. The coating process itself is monitored by the electrostatic charge of the particles.

  1. Communication Optimizations for Fine-Grained UPCApplications

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wei-Yu; Iancu, Costin; Yelick, Katherine

    2005-07-08

    Global address space languages like UPC exhibit high performance and portability on a broad class of shared and distributed memory parallel architectures. The most scalable applications use bulk memory copies rather than individual reads and writes to the shared space, but finer-grained sharing can be useful for scenarios such as dynamic load balancing, event signaling, and distributed hash tables. In this paper we present three optimization techniques for global address space programs with fine-grained communication: redundancy elimination, use of split-phase communication, and communication coalescing. Parallel UPC programs are analyzed using static single assignment form and a data flow graph, which are extended to handle the various shared and private pointer types that are available in UPC. The optimizations also take advantage of UPC's relaxed memory consistency model, which reduces the need for cross thread analysis. We demonstrate the effectiveness of the analysis and optimizations using several benchmarks, which were chosen to reflect the kinds of fine-grained, communication-intensive phases that exist in some larger applications. The optimizations show speedups of up to 70 percent on three parallel systems, which represent three different types of cluster network technologies.

  2. AC susceptibilities of grain-textured superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, N. [Department of Electrical Engineering, Kyushu Sangyo University, 2-3-1 Matsukadai, 813-8503 Fukuoka (Japan)], E-mail: saka@te.kyusan-u.ac.jp; Fukuda, Y.; Koga, M.; Akune, T. [Department of Electrical Engineering, Kyushu Sangyo University, 2-3-1 Matsukadai, 813-8503 Fukuoka (Japan); Khan, H.R. [Institut von Ionenstrahl und Vakuum Technologie, 73728 Esslingen (Germany); Lueders, K. [Freie Universitaet Berlin, Arnimallee, Fac.Physik, D-14195 Berlin (Germany)

    2008-09-15

    In-phase {chi}{sub n}' and out-phase {chi}{sub n}'' components of nth harmonics of AC susceptibility with measuring parameters of a DC magnetic field B{sub dc}, an amplitude B{sub a} and a frequency f of the superimposed AC magnetic fields give substantial information of the superconducting properties. In low-T{sub c} metallic superconductors, {chi}{sub 1}' shows smooth transition and {chi}{sub 1}'' does single peak. High-T{sub c} oxide superconductors with anisotropic and grain-textured structures show deformed complex characteristics. Double peaks in {chi}{sub 1}'' and shoulders in {chi}{sub 1}' appear in AC susceptibility of Hg-1223 superconductors. Instead of simple Bean model, a grained model, where the superconducting grains are immersed in weak superconducting matrix, are proposed. The susceptibilities numerically analyzed using the model show varied and deformed curves and are successfully compared with the measured results.

  3. Effect of foliar fertilization on soybean grain yield

    OpenAIRE

    Mandić V.; Simić A.; Krnjaja V.; Bijelić Z.; Tomić Z.; Stanojković A.; Ruzić-Muslić D.

    2015-01-01

    The aim of this investigation was to estimate the effects of foliar fertilization on quantitative traits (plant height, first pod height, number of nodes per plant, number of pods per plant, number of grain per plant, grain yield per plant, 1000-grain weight and grain yield) in two soybean cultivars (Balkan and Bečejka). Studied cultivars belong to different maturity groups (Balkan - I and Bečejka - 0). Four treatments of fertilization were tested: control ...

  4. Annealing-induced Grain Refinement in a Nanostructured Ferritic Steel

    Institute of Scientific and Technical Information of China (English)

    Limin Wang; Zhenbo Wangt; Sheng Guo; Ke Lu

    2012-01-01

    A nanostructured surface layer with a mean ferrite grain size of -8 nm was produced on a Fe-gCr steel by means of surface mechanical attrition treatment. Upon annealing, ferrite grains coarsen with increasing temperature and their sizes increase to -40 nm at 973 K. Further increasing annealing temperature leads to an obvious reduction of ferrite grain sizes, to -14 nm at 1173 K. The annealing-induced grain refinement is analyzed in terms of phase transformations in the nanostructured steel.

  5. Acceleration of small astrophysical grains due to charge fluctuations

    CERN Document Server

    Ivlev, A V; Tsytovich, V N; de Angelis, U; Hoang, Thiem; Morfill, G E

    2010-01-01

    We discuss a novel mechanism of dust acceleration which dominates for particles smaller than $\\sim0.1 \\mu$m. The acceleration is caused by charge fluctuations occurring on grains during their mutual Coulomb collisions. The energy source for the acceleration are the irreversible plasma fluxes continuously absorbed by grains. In particular, this mechanism of charge-fluctuation-induced acceleration affects the rate of grain coagulation and shattering of the population of small grains.

  6. Recrystallization at grain boundaries in deformed copper bicrystals

    NARCIS (Netherlands)

    Heller, H.W.F.; Verbraak, C.A.; Kolster, B.H.

    1984-01-01

    The role of specific grain boundaries in the nucleation of recrystallization textures is demonstrated by experiments on copper bicrystals. It is deduced that the major part of the recrystallized grains that have nucleated at the grain boundary can be traced back to having nucleated in {100} <001>, {

  7. 7 CFR 800.61 - Prohibited grain handling practices.

    Science.gov (United States)

    2010-01-01

    ... Official United States Standards for Grain. (3) Add water to grain for purposes other than milling, malting... by the Official United States Standards for Grain, may be blended to adjust quality. Broken corn or... material or dockage has been added to the broken corn or broken kernels. (2) Insect and fungi...

  8. Association of Phytate Formation with Grain Filling in Rice

    Institute of Scientific and Technical Information of China (English)

    WANG Ruo-zhong; XIAO Lang-tao; DING Jun-hui; YAN Qin-quan

    2003-01-01

    The grain-filling characteristics of six rice varieties (combinations) and the relationships between their relative biochemistry composition during phytate synthesizing and grain plumpness were studied. Regarding results for ISHR1,ISHR2, R198 and JW21, with good grain plumpness, the two-step-filling in superior spikelets and inferior spikelets was not clear, while for ISHR3 and 559, with poor grain plumpness, it was very clear. From booting stage to flowering stage, the contents of phytate and inositol in varieties with good grain plumpness was obviously higher than those in varieties with poor grain plumpness. While at grain filling stage, the content of inorganic phosphorus in varieties with poor grain plumpness was obviously higher than that in varieties with good grain plumpness. The contents of phytate and inositol from booting stage to flowering stage was highly significantly correlated with the initial filling power (RO), the mean filling rate (RM) and grain filling percentage (PGF), and the content of inorganic phosphorus at grain filling stage was negatively significantly correlated with R0, FM and PGF. Furthermore, effective approach to improving grain filling was put forward.

  9. Mechanical properties of ultra-fine grained zirconia ceramics

    NARCIS (Netherlands)

    Theunissen, G.S.A.M.; Bouma, J.S.; Winnubst, A.J.A.; Burggraaf, A.J.

    1992-01-01

    The mechanical properties of tetragonal zirconia (TZP) materials doped with Y, Ce or Ti were studied as a function of temperature and grain size. Fine grained Y-TZP (grain size < 0.3 mgrm) shows values for fracture toughness and strength at room temperature, which are comparable with the coarse grai

  10. Ancient whole grain gluten-free egg-free Pasta

    Science.gov (United States)

    The USDA food guide recommends that at least ½ of all the grains eaten should be whole grains. The FDA allows food Health Claim labels for food containing 51% whole gains and 11 g of dietary fiber per serving. This is the only report demonstrating innovative ancient whole grain, gluten-free, egg-fre...

  11. Effects of whole grains on coronary heart disease risk.

    Science.gov (United States)

    Harris, Kristina A; Kris-Etherton, Penny M

    2010-11-01

    Characterizing which types of carbohydrates, including whole grains, reduce the risk for coronary heart disease (CHD) is challenging. Whole grains are characterized as being high in resistant carbohydrates as compared with refined grains, meaning they typically are high in fiber, nutrients, and bound antioxidants. Whole grain intake consistently has been associated with improved cardiovascular disease outcomes, but also with healthy lifestyles, in large observational studies. Intervention studies that assess the effects of whole grains on biomarkers for CHD have mixed results. Due to the varying nutrient compositions of different whole grains, each could potentially affect CHD risk via different mechanisms. Whole grains high in viscous fiber (oats, barley) decrease serum low-density lipoprotein cholesterol and blood pressure and improve glucose and insulin responses. Grains high in insoluble fiber (wheat) moderately lower glucose and blood pressure but also have a prebiotic effect. Obesity is inversely related to whole grain intake, but intervention studies with whole grains have not produced weight loss. Visceral fat, however, may be affected favorably. Grain processing improves palatability and can have varying effects on nutrition (e.g., the process of milling and grinding flour increases glucose availability and decreases phytochemical content whereas thermal processing increases available antioxidants). Understanding how individual grains, in both natural and processed states, affect CHD risk can inform nutrition recommendations and policies and ultimately benefit public health.

  12. Causality Between Market Liquidity and Depth for Energy and Grains

    NARCIS (Netherlands)

    R. Sari (Ramazan); S.M. Hammoudeh (Shawkat); C-L. Chang (Chia-Lin); M.J. McAleer (Michael)

    2011-01-01

    textabstractThis paper examines the roles of futures prices of crude oil, gasoline, ethanol, corn, soybeans and sugar in the energy-grain nexus. It also investigates the own- and cross-market impacts for lagged grain trading volume and open interest in the energy and grain markets. According to the

  13. Does whole grain consumption alter gut microbiota and satiety?

    Science.gov (United States)

    This review summarizes recent studies examining whole grain consumption and its effect on gut microbiota and satiety in healthy humans. Both individual whole grain cereals and interventions with combined whole grain cereals were considered. Possible links between the fermentation of non-digestible c...

  14. Ammonia disinfection of corn grains intended for ethanol fermentation

    Directory of Open Access Journals (Sweden)

    Magdalena Broda

    2009-12-01

    Full Text Available Background. Bacterial contamination is an ongoing problem for commercial bioethanol plants. It concerns factories using grain and also other raw materials for ethanol fermentation. Bacteria compete with precious yeasts for sugar substrates and micronutrients, secrete lactic and acetic acids, which are toxic for yeast and this competition leads to significant decrease of bioethanol productivity. For this study, bacterial contamination of corn grain was examined. Then the grain was treated by ammonia solution to reduce microbial pollution and after that the microbiological purity of grain was tested one more time. Disinfected and non-disinfected corn grains were ground and fermentation process was performed. Microbiological purity of this process and ethanol yield was checked out. Material and methods. The grain was disinfected by ammonia solution for two weeks. Then the grain was milled and used as a raw material for the ethanol fermentation. The fermentation process was carried out in 500-ml Erlenmeyer flasks. Samples were withdrawn for analysis at 0, 24, 48, 72 hrs. The number of total viable bacteria, lactic acid bacteria, acetic acid bacteria, anaerobic bacteria and the quantity of yeasts and moulds were signified by plate method. Results. Ammonia solution effectively reduces bacterial contamination of corn grain. Mash from grain disinfected by ammonia contains less undesirable microorganisms than mash from crude grain. Moreover, ethanol yield from disinfected grain is at the highest level. Conclusions. The ammonia solution proved to be a good disinfection agent for grain used as a raw material for bioethanol fermentation process.

  15. Supplying materials needed for grain growth characterizations of nano-grained UO2

    Energy Technology Data Exchange (ETDEWEB)

    Mo, Kun [Argonne National Lab. (ANL), Argonne, IL (United States); Miao, Yinbin [Argonne National Lab. (ANL), Argonne, IL (United States); Yun, Di [Argonne National Lab. (ANL), Argonne, IL (United States); Jamison, Laura M. [Argonne National Lab. (ANL), Argonne, IL (United States); Lian, Jie [Rensselaer Polytechnic Inst., Troy, NY (United States); Yao, Tiankei [Rensselaer Polytechnic Inst., Troy, NY (United States)

    2015-09-30

    This activity is supported by the US Nuclear Energy Advanced Modeling and Simulation (NEAMS) Fuels Product Line (FPL) and aims at providing experimental data for the validation of the mesoscale simulation code MARMOT. MARMOT is a mesoscale multiphysics code that predicts the coevolution of microstructure and properties within reactor fuel during its lifetime in the reactor. It is an important component of the Moose-Bison-Marmot (MBM) code suite that has been developed by Idaho National Laboratory (INL) to enable next generation fuel performance modeling capability as part of the NEAMS Program FPL. In order to ensure the accuracy of the microstructure based materials models being developed within the MARMOT code, extensive validation efforts must be carried out. In this report, we summarize our preliminary synchrotron radiation experiments at APS to determine the grain size of nanograin UO2. The methodology and experimental setup developed in this experiment can directly apply to the proposed in-situ grain growth measurements. The investigation of the grain growth kinetics was conducted based on isothermal annealing and grain growth characterization as functions of duration and temperature. The kinetic parameters such as activation energy for grain growth for UO2 with different stoichiometry are obtained and compared with molecular dynamics (MD) simulations.

  16. Proteomics of Rice Grain under High Temperature Stress

    Directory of Open Access Journals (Sweden)

    Toshiaki eMitsui

    2013-03-01

    Full Text Available Recent proteomic analyses revealed dynamic changes of metabolisms during rice grain development. Interestingly, proteins involved in glycolysis, citric acid cycle, lipid metabolism, and proteolysis were accumulated at higher levels in mature grain than those of developing stages. High temperature stress in rice ripening period causes damaged (chalky grains which have loosely packed round shape starch granules. The high temperature stress response on protein expression is complicated, and the molecular mechanism of the chalking of grain is obscure yet. Here, the current state on the proteomics research of rice grain grown under high temperature stress is briefly overviewed.

  17. Strategic Analysis on Objectives of National Grain Security

    Institute of Scientific and Technical Information of China (English)

    Hong; YANG

    2015-01-01

    Price of global agricultural products rises with great fluctuation. China’s food price also increases constantly. This leads to high concern of both at home and abroad for food and grain security. On the basis of making an overall analysis on current situation of grain security and making judgment on future grain security in China,this paper analyzed objectives,strategies and policies of national grain security in the new period. Finally,it came up with strategies and policy recommendations for improving agricultural production and guaranteeing national grain security.

  18. Foreign Grain Security Mechanisms and Implications for China

    Institute of Scientific and Technical Information of China (English)

    Shuhua; CAO; Lei; NIE; Weipeng; MA

    2014-01-01

    With constant growth of China’s population and increasingly serious situation of farmland protection,the grain security has become a hot issue of China.This study firstly elaborated grain security measures in grain exporters,such as the United States,Australia,and EU,and grain importers such as Japan,South Korea and India.In line with these security measures,it analyzed implementation background of these policies.Finally,combining social and economic development situations and natural resource endowment of China,it revealed the implications of these measures for China and came up with policy recommendations for China’s grain security.

  19. Recrystallization from a Three-Grain Crystalline Iron

    Directory of Open Access Journals (Sweden)

    Bo Zhao

    2015-01-01

    Full Text Available The solid state recrystallization and grain boundary migrations in an iron nanoparticle Fe2616 with three grains were studied by a molecular dynamics simulation. It was found that nucleation rates could be determined as the smaller grains were consumed by the larger ones. Moreover, the grain disorder was more important than the misorientation angle in governing the rates. Suggestions about the critical nuclei for the recrystallization are proposed. No obvious interaction between the grain boundaries was observed in the example studied in this report.

  20. Kinetic Modeling of Sunflower Grain Filling and Fatty Acid Biosynthesis

    Science.gov (United States)

    Durruty, Ignacio; Aguirrezábal, Luis A. N.; Echarte, María M.

    2016-01-01

    Grain growth and oil biosynthesis are complex processes that involve various enzymes placed in different sub-cellular compartments of the grain. In order to understand the mechanisms controlling grain weight and composition, we need mathematical models capable of simulating the dynamic behavior of the main components of the grain during the grain filling stage. In this paper, we present a non-structured mechanistic kinetic model developed for sunflower grains. The model was first calibrated for sunflower hybrid ACA855. The calibrated model was able to predict the theoretical amount of carbohydrate equivalents allocated to the grain, grain growth and the dynamics of the oil and non-oil fraction, while considering maintenance requirements and leaf senescence. Incorporating into the model the serial-parallel nature of fatty acid biosynthesis permitted a good representation of the kinetics of palmitic, stearic, oleic, and linoleic acids production. A sensitivity analysis showed that the relative influence of input parameters changed along grain development. Grain growth was mostly affected by the specific growth parameter (μ′) while fatty acid composition strongly depended on their own maximum specific rate parameters. The model was successfully applied to two additional hybrids (MG2 and DK3820). The proposed model can be the first building block toward the development of a more sophisticated model, capable of predicting the effects of environmental conditions on grain weight and composition, in a comprehensive and quantitative way. PMID:27242809

  1. Grain Growth Behavior in Sintered Nd-Fe-B Magnets

    Institute of Scientific and Technical Information of China (English)

    Liu Xianglian; Zhou Shouzeng

    2007-01-01

    The Nd2Fe14B grain growth behavior in sintered Nd-Fe-B magnets was quantitatively described. The effects of sintering temperature and time, and alloy powder size and its distribution on grain growth process were analyzed. Hence, possible grain growth mechanisms in these magnets were qualitatively discussed. The Nd2Fe14B grain growth proceeded at quite a high rate in the initial 0~1 h of sintering and from then onwards the grain growth rate decreased. A large average particle size or a wide particle size distribution of initial alloy powders was found to remarkably accelerate the grain growth process and even result in the occurrence of abnormal grain growth. On the basis of experimental results, two grain growth mechanisms were considered to operate during sintering of Nd-Fe-B magnets, that is, dissolution and re-precipitation of Nd2Fe14B particles, and Nd2Fe14B particle growth by coalescence. It was believed that Nd2Fe14B particle growth by coalescence not only produced a large average grain size and a wide grain size distribution, but also was the fundamental reason for the formation of abnormally large grains in the microstructure of sintered Nd-Fe-B magnets.

  2. A new approach to grain boundary engineering for nanocrystalline materials.

    Science.gov (United States)

    Kobayashi, Shigeaki; Tsurekawa, Sadahiro; Watanabe, Tadao

    2016-01-01

    A new approach to grain boundary engineering (GBE) for high performance nanocrystalline materials, especially those produced by electrodeposition and sputtering, is discussed on the basis of some important findings from recently available results on GBE for nanocrystalline materials. In order to optimize their utility, the beneficial effects of grain boundary microstructures have been seriously considered according to the almost established approach to GBE. This approach has been increasingly recognized for the development of high performance nanocrystalline materials with an extremely high density of grain boundaries and triple junctions. The effectiveness of precisely controlled grain boundary microstructures (quantitatively characterized by the grain boundary character distribution (GBCD) and grain boundary connectivity associated with triple junctions) has been revealed for recent achievements in the enhancement of grain boundary strengthening, hardness, and the control of segregation-induced intergranular brittleness and intergranular fatigue fracture in electrodeposited nickel and nickel alloys with initial submicrometer-grained structure. A new approach to GBE based on fractal analysis of grain boundary connectivity is proposed to produce high performance nanocrystalline or submicrometer-grained materials with desirable mechanical properties such as enhanced fracture resistance. Finally, the potential power of GBE is demonstrated for high performance functional materials like gold thin films through precise control of electrical resistance based on the fractal analysis of the grain boundary microstructure.

  3. A new approach to grain boundary engineering for nanocrystalline materials

    Directory of Open Access Journals (Sweden)

    Shigeaki Kobayashi

    2016-11-01

    Full Text Available A new approach to grain boundary engineering (GBE for high performance nanocrystalline materials, especially those produced by electrodeposition and sputtering, is discussed on the basis of some important findings from recently available results on GBE for nanocrystalline materials. In order to optimize their utility, the beneficial effects of grain boundary microstructures have been seriously considered according to the almost established approach to GBE. This approach has been increasingly recognized for the development of high performance nanocrystalline materials with an extremely high density of grain boundaries and triple junctions. The effectiveness of precisely controlled grain boundary microstructures (quantitatively characterized by the grain boundary character distribution (GBCD and grain boundary connectivity associated with triple junctions has been revealed for recent achievements in the enhancement of grain boundary strengthening, hardness, and the control of segregation-induced intergranular brittleness and intergranular fatigue fracture in electrodeposited nickel and nickel alloys with initial submicrometer-grained structure. A new approach to GBE based on fractal analysis of grain boundary connectivity is proposed to produce high performance nanocrystalline or submicrometer-grained materials with desirable mechanical properties such as enhanced fracture resistance. Finally, the potential power of GBE is demonstrated for high performance functional materials like gold thin films through precise control of electrical resistance based on the fractal analysis of the grain boundary microstructure.

  4. Predicting Wheat Grain Number by Photothermal Quotient in Anthesis Stage

    Directory of Open Access Journals (Sweden)

    A. Abhari

    2014-12-01

    Full Text Available This study was conducted to examine effects photothermal Quotient on grain number of four wheat cultivars under four planting dates and four replications. The experiment conducted at the Sabzevar Agricultural Sciences Research during 2007-2008 and 2008-2009. Various responses functions were evaluated to quantify the response of grain number to influencing parameters (environmental and non- environmental- based factors. The best relationship was found between grain number and grain yield, thus we evaluated and modeled other influence parameters (photothermal Quotient and temperature on grain number. Result indicated that the grain number per area with mean temperature (r=0.88 at stem elongation to anthesis stage the highest correlation coefficient and grain number reduced with increasing temperature, in first and second years,12150.3 and 1118.9 grain number /°C respectively. In 27 and 30 ° C mean temperature grain was not formed. Qquadratic equation was obtained between grain number per unit area and photothermal Quotient at stem elongation to anthesis stage and the highest grain number of wheat were observed in 0.55 photothermal Quotient.

  5. Grain structure evolution during cryogenic rolling of alpha brass

    Energy Technology Data Exchange (ETDEWEB)

    Konkova, T. [Institute for Metals Superplasticity Problems, Rssian Academy of Science, 39 Khalturin Str., Ufa 450001 (Russian Federation); Mironov, S. [Department of Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02 Aramaki-aza-Aoba, Sendai 980-8579 (Japan); Korznikov, A. [Institute for Metals Superplasticity Problems, Rssian Academy of Science, 39 Khalturin Str., Ufa 450001 (Russian Federation); National Research Tomsk State University, 36 Lenina av., Tomsk 634050 (Russian Federation); Korznikova, G. [Institute for Metals Superplasticity Problems, Rssian Academy of Science, 39 Khalturin Str., Ufa 450001 (Russian Federation); Myshlyaev, M.M. [Baikov Institute of Metallurgy and Material Science, Russian Academy of Science, 49 Lenin-av., Moscow 119991 (Russian Federation); Semiatin, S.L. [Air Force Research Laboratory, Materials and Manufacturing Directorate, AFRL/RXCM, Wright-Patterson AFB, OH 45433-7817 (United States)

    2015-04-25

    Highlights: • Cryogenic rolling produced inhomogeneous ultrafine-grained microstructure. • Grain refinement was mainly related with twinning and shear banding. • Grain refinement preferentially occurred in Copper {1 1 0}(1 1 2) grains. - Abstract: High-resolution electron backscatter diffraction (EBSD) was used to study grain structure development during cryogenic rolling of Cu–29.5Zn brass. Microstructure evolution was found to be broadly similar to that occurring during rolling at room temperature. Specifically, favorably-oriented grains (Copper {1 1 2}(1 1 1) and S {1 2 3}(6 3 4)) experienced profuse deformation twinning followed by extensive shear banding. This eventually produced an ultrafine structure with a mean grain size of ~0.2 μm. On the other hand, grains with crystallographic orientations close to Brass {1 1 0}(1 1 2) and Goss {1 1 0}(1 0 0) were found to be stable against twinning/shear banding and thus showed no significant grain refinement. As a result, the final structure developed in heavily-rolled material was distinctly inhomogeneous consisting of mm-scale remnants of original grains with poorly developed substructure and ultra-fine grain domains.

  6. Grain refinement in magnesium alloy AZ31 during hot deformation

    Energy Technology Data Exchange (ETDEWEB)

    Yang Xuyue; Miura, H.; Sakai, T. [Dept. of Mechanical Engineering and Intelligent Systems, Univ. of Electro-Communications, Chofu, Tokyo (Japan)

    2004-07-01

    The deformation behavior and structure changes of magnesium alloy AZ31 were studied in compression at temperatures ranging from 523 K to 673 K and at a strain rate of 3 x 10{sup -3} s{sup -1}. They depend sensitively on deformation temperature. At high temperatures, grain fragmentation takes place due to frequent formation of kink bands initially at corrugated grain boundaries and then in grain interiors, followed by full development of new grains in high strain. At lower temperatures, in contrast, twinning takes place in rather coarse grains and kink bands are formed mainly in finer original ones in low strain. It is concluded that new grain evolution can be controlled by a deformation-induced continuous reaction resulting in grain fragmentation by kink bands, i.e. continuous dynamic recrystallization (cDRX). The latter is discussed comparing with conventional, i.e. discontinuous, DRX. (orig.)

  7. Grain growth in nanocrystalline Ni-20%Fe alloy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Y.B.; Park, J.; Kim, S.S. [Dept. of Materials Science and Metallurgical Engineering, Sunchon National Univ., Sunchon (Korea); Yim, T.H. [Materials Process Technology R and D Center, Korea Inst. of Industrial Technology, Chonan (Korea)

    2001-07-01

    Grain growth was investigated in a nanocrystalline Ni-20wt-%Fe alloy fabricated by an electrodeposition method, and its effect on the texture evolution was examined. The as-deposited specimens revealed a strong {l_brace}100{r_brace} and a weak {l_brace}111{r_brace} fibre-type textures. Grain growth in the material occurred on annealing beyond 370 C and resulted in the texture change that the {l_brace}111{r_brace} fibre strongly developed at the expense of the {l_brace}100{r_brace} fibre. It was observed using orientation imaging microscopy (OIM) that the {l_brace}111{r_brace} grains are much coarser than other oriented grains in the early stages of grain growth. The relationship between the texture evolution and the microstructural change accompanied by grain growth is interpreted and discussed in terms of the orientation dependency of grain growth. (orig.)

  8. Textures and grain growth in nanocrystalline Fe-Ni alloys

    Energy Technology Data Exchange (ETDEWEB)

    Seo, J.H.; Kim, J.K.; Park, Y.B. [Dept. of Materials Science and Metallurgical Engineering, Nanomaterials Research Center, Sunchon National Univ. (Korea); Yim, T.H. [Production Technology Center, Korea Inst. of Industrial Technology, Chonan (Korea)

    2005-07-01

    The texture evolution due to grain growth that takes place during annealing was investigated in nanocrystalline Fe-Ni alloys fabricated by using a continuous electroforming method. In the current materials, grain growth occurred during annealing at much lower temperatures than in conventional coarse-grained counterparts. With regard to the macrotextures, the as-deposited textures were of fibre-type characterized by strong <100>//ND and weak <111>//ND components, and the occurrence of grain growth resulted in the strong development of the <111>//ND fibre texture with the minor <100>//ND components. It was clarified using orientation imaging microscopy that abnormal growth of the <111>//ND grains in the early stages of grain growth plays an important role on the texture evolution. The origin of the abnormal grain growth has been discussed in terms of the orientation dependence of energy density. (orig.)

  9. Landau-Lifhsitz-Bloch equation for exchange coupled grains

    CERN Document Server

    Vogler, Christoph; Bruckner, Florian; Suess, Dieter

    2014-01-01

    Heat assisted recording is a promising technique to further increase the storage density in hard disks. Multilayer recording grains with graded Curie temperature is discussed to further assist the write process. Describing the correct magnetization dynamics of these grains, from room temperature to far above the Curie point, during a write process is required for the calculation of bit error rates. We present a coarse grained approach based on the Landau-Lifshitz-Bloch (LLB) equation to model exchange coupled grains with low computational effort. The required temperature dependent material properties such as the zero-field equilibrium magnetization as well as the parallel and normal susceptibilities are obtained by atomistic Landau-Lifshitz-Gilbert (LLB) simulations. Each grain is described with one magnetization vector. In order to mimic the atomistic exchange interaction between the grains a special treatment of the exchange field in the coarse grained approach is presented.

  10. Detectability of dirty dust grains in brown dwarf atmospheres

    CERN Document Server

    Helling, C H; Thi, W F; Woitke, P; Helling, CH.

    2006-01-01

    Dust clouds influence the atmospheric structure of brown dwarfs, and they affect the heat transfer and change the gas-phase chemistry. However, the physics of their formation and evolution is not well understood. In this letter, we predict dust signatures and propose a potential observational test of the physics of dust formation in brown dwarf atmosphere based on the spectral features of the different solid components predicted by dust formation theory. A momentum method for the formation of dirty dust grains (nucleation, growth, evaporation, drift) is used in application to a static brown dwarf atmosphere structure to compute the dust grain properties, in particular the heterogeneous grain composition and the grain size. Effective medium and Mie theory are used to compute the extinction of these spherical grains. Dust formation results in grains whose composition differs from that of grains formed at equilibrium. Our kinetic model predicts that solid amorphous SiO2[s] (silica) is one of the most abundant so...

  11. Nanocrystalline and ultrafine grain copper obtained by mechanical attrition

    Directory of Open Access Journals (Sweden)

    Rodolfo Rodríguez Baracaldo

    2011-03-01

    Full Text Available This article presents a method for the sample preparation and characterisation of bulk copper having grain size lower than 1 μm (ultra-fine grain and lower than 100 nm grain size (nanocrystalline. Copper is initially manufactured by a milling/alloying me- chanical method thereby obtaining a powder having a nanocrystalline structure which is then consolidated through a process of warm compaction at high pressure. Microstructural characterisation of bulk copper samples showed the evolution of grain size during all stages involved in obtaining it. The results led to determining the necessary conditions for achieving a wide range of grain sizes. Mechanical characterisation indicated an increase in microhardness to values of around 3.40 GPa for unconsolida- ted nanocrystalline powder. Compressivee strength was increased by reducing the grain size, thereby obtaining an elastic limit of 650 MPa for consolidated copper having a ~ 62 nm grain size.

  12. Towards the limit of ferroelectric nanosized grains

    Science.gov (United States)

    Roelofs, A.; Schneller, T.; Szot, K.; Waser, R.

    2003-02-01

    Ferroelectric random access memories are non-volatile, low voltage, high read/write speed devices which have been introduced into the market in recent years and which show the clear potential of future gigabit scale universal non-volatile memories. The ultimate limit of this concept will depend on the ferroelectric limit (synonymous superparaelectric limit), i.e. the size limit below which the ferroelectricity is quenched. While there are clear indications that 2D ferroelectric oxide films may sustain their ferroelectric polarization below 4 nm in thickness (Tybell T, Ahn C H and Triscone J M 1999 Appl. Phys. Lett. 75 856), the limit will be quite different for isolated 3D nanostructures (nanograins, nanoclusters). To investigate scaling effects of ferroelectric nanograins on Si wafers, we studied PbTiO3 (PTO) and Pb(ZrxTi1-x)O3 grown by a self-assembly chemical solution deposition method. Preparing highly diluted precursor solutions we achieved single separated ferroelectric grains with grain sizes ranging from 200 nm down to less than 20 nm. For grains smaller than 20 nm, no piezoresponse was observed and we suppose this could be due to the transition from the ferroelectric to the paraelectric phase which has no spontaneous polarization. Recent calculations (Zhong W L, Wang Y G, Zhang P L and Qu B D 1994 Phys. Rev. B 50 698) and experiments (Jiang B, Peng J L, Zhong W L and Bursill L A 2000 J. Appl. Phys. 87 3462) showed that the ferroelectricity of fine ferroelectric particles decrease with decreasing particle size. From these experiments the extrapolated critical size of PTO particles was found to be around 4.2-20 nm.

  13. The Gravitational Description of Coarse Grained Microstates

    CERN Document Server

    Alday, L F; Messamah, I; Alday, Luis F.; Boer, Jan de; Messamah, Ilies

    2006-01-01

    In this paper we construct a detailed map from pure and mixed half-BPS states of the D1-D5 system to half-BPS solutions of type IIB supergravity. Using this map, we can see how gravity arises through coarse graining microstates, and we can explicitly confirm the microscopic description of conical defect metrics, the M=0 BTZ black hole and of small black rings. We find that the entropy associated to the natural geometric stretched horizon typically exceeds that of the mixed state from which the geometry was obtained.

  14. An algebraic approach to coarse graining

    CERN Document Server

    Markopoulou, F

    2000-01-01

    We propose that Kreimer's method of Feynman diagram renormalization via a Hopf algebra of rooted trees can be fruitfully employed in the analysis of block spin renormalization or coarse graining of inhomogeneous statistical systems. Examples of such systems include spin foam formulations of non-perturbative quantum gravity as well as lattice gauge and spin systems on irregular lattices and/or with spatially varying couplings. We study three examples which are Z_2 lattice gauge theory on irregular 2-dimensional lattices, Ising/Potts models with varying bond strengths and (1+1)-dimensional spin foam models.

  15. Influence of Grain Boundary on Melting

    Institute of Scientific and Technical Information of China (English)

    王暾; 周富信; 刘曰武

    2001-01-01

    The temperature behaviour of an Al bicrystal with surfaces consisting of (110) and (111) crystals is simulated using molecular dynamics. The result shows that the (110) crystal losses its crystalline order at 820K, whereas the disorder does not propagate through the (111) crystal at this temperature. Instead, some disordered atoms are recrystallized into the (111) crystal and the initial grain boundary changes into a stable order-disorder interface. Thus, it was discovered that at a temperature near its melting point, the (111) crystal grew and obstructed the propagation of disorder. Such an obstruction is helpfulfor understanding melting.

  16. The gravitational description of coarse grained microstates

    Energy Technology Data Exchange (ETDEWEB)

    Alday, Luis F. [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, 3508 TD Utrecht (Netherlands); Boer, Jan de [Instituut voor Theoretische Fysica, Valckenierstraat 65, 1018XE Amsterdam (Netherlands); Messamah, Ilies [Instituut voor Theoretische Fysica, Valckenierstraat 65, 1018XE Amsterdam (Netherlands)

    2006-12-15

    In this paper we construct a detailed map from pure and mixed half-BPS states of the D1-D5 system to half-BPS solutions of type IIB supergravity. Using this map, we can see how gravity arises through coarse graining microstates, and we can explicitly confirm the microscopic description of conical defect metrics, the M = 0 BTZ black hole and of small black rings. We find that the entropy associated to the natural geometric stretched horizon typically exceeds that of the mixed state from which the geometry was obtained.

  17. Electronic and molecular structure of carbon grains

    Science.gov (United States)

    Almloef, Jan; Luethi, Hans-Peter

    1990-01-01

    Clusters of carbon atoms have been studied with large-scale ab initio calculations. Planar, single-sheet graphite fragments with 6 to 54 atoms were investigated, as well as the spherical C(sub 60) Buckminsterfullerene molecule. Polycyclic aromatic hydrocarbons (PAHs) have also been considered. Thermodynamic differences between diamond- and graphite-like grains have been studied in particular. Saturation of the peripheral bonds with hydrogen is found to provide a smooth and uniform convergence of the properties with increasing cluster size. For the graphite-like clusters the convergence to bulk values is much slower than for the three-dimensional complexes.

  18. Fine grain tungsten produced with nanoscale powder

    Institute of Scientific and Technical Information of China (English)

    Tao Lin; Fang Zhao; Liying Zhang; Chengyi Wu; Zhimeng Guo

    2005-01-01

    Nanoscale tungsten powder was prepared by reducing nanoscale tungsten trioxide in hydrogen to WO2.90 and further to W powder. After compacted with a rubber die, the nanoscale tungsten powder was sintered in a high-temperature dilatometer to investigate its shrinkage process. The results show that the compact of the nanoscale tungsten powder starts to shrink at 1050℃ and ends at 1500℃. The shrinkage rate reaches the maximum value at 1210℃. The relative density of sintered samples is 96.4%, and its grain size is about 5.8 μm.

  19. Strength of Rocks Affected by Deformation Enhanced Grain Growth

    Science.gov (United States)

    Kellermann Slotemaker, A.; de Bresser, H.; Spiers, C.

    2005-12-01

    One way of looking into the possibility of long-term strength changes in the lithosphere is to study transient effects resulting from modifications of the microstructure of rocks. It is generally accepted that mechanical weakening may occur due to progressive grain size refinement resulting from dynamic recrystallization. A decrease in grain size may induce a switch from creep controlled by grain size insensitive dislocation mechanisms to creep governed by grain size sensitive (GSS) mechanisms involving diffusion and grain boundary sliding processes. This switch forms a well-known scenario to explain localization in the lithosphere. However, fine-grained rocks in localized deformation zones are prone to grain coarsening due to surface energy driven grain boundary migration (SED-GBM). This might harden the rock, affecting its role in localizing strain in the long term. The question has arisen if grain growth by SED-GBM in a rock deforming in the GSS creep field can be significantly affected by strain. The broad aim of this study is to shed more light onto this. We have experimentally investigated the microstructural and strength evolution of fine-grained (~0.6 μm) synthetic forsterite and Fe-bearing olivine aggregates that coarsen in grain size while deforming by GSS creep at elevated pressure (600 MPa) and temperature (850-1000 °C). The materials were prepared by `sol-gel' method and contained 0.3-0.5 wt% water and 5-10 vol% enstatite. We performed i) static heat treatment tests of various time durations involving hot isostatic pressing (HIP), and ii) heat treatment tests starting with HIP and continuing with deformation up to 45% axial strain at strain rates in the range 4x10-7 - 1x10-4 s-1. Microstructures were characterized by analyzing full grain size distributions and textures using SEM/EBSD. In addition to the experiments, we studied microstructural evolution in simple two-dimensional numerical models, combining deformation and SED-GBM by means of the

  20. Grain destruction in shocks in the interstellar medium

    Science.gov (United States)

    Jones, A. P.; Tielens, A. G. G. M.; Hollenbach, D. J.; McKee, C. F.

    1994-10-01

    Destruction of interstellar dust occurs predominantly in supernova shock waves in the warm neutral/ionized medium (density approximately = 0.25/cu cm, temperature approximately = 104 K). Recent theoretical developments and laboratory data for sputtering processes and grain-grain collisional vaporization allows us to better evaluate the grain destruction rate in interstellar shocks in the warm medium. We find that, independent of composition, grain destruction in supernova blast waves is dominated by nonthermal sputtering for shock velocities greater than 50 km/s and less than or equal to 150 km/s and thermal sputtering at higher shock velocities. We use a detailed scheme for the vaporization of grains colliding at high velocities (vs greater than or equal to 20 km/s) and show that the grain-grain collision destruction process is only dominant for shock velocities of less than or equal to 50-80 km/s and is less important than previously assumed. Nevertheless, the grain-grain destruction rates are of order 30%-90% of the sputtering rates at vs greater than 100 km/s and less than 200 km/s and are important in vaporizing the cores of grains. Detailed results for grain destruction as a function of grain size and composition are presented. We also present results for silicon carbide, iron, ice, and porous test particles. For carbonaceous grains we find that the fractional destruction is less than or equal to 0.29, and for silicate it is less than or equal to 0.45, for vs less than or equal to 200 km/s. We have calculated grain lifetimes, using the three-phase model of the interstellar medium, and find lifetimes of 4 x 108 yr for carbonaceous grains and 2.2 x 108 yr for silicate grains. Given that the typical stardust injection timescale of 2.5 x 109 yr, we conclude that efficient mechanisms for grain growth in the interstellar medium must exist in order that a significant fraction of the refractory elements be incorporated in dust, as observed. Therefore, although our

  1. Grain boundary and grain interior conduction in {gamma}'-Bi{sub 2}MoO{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Vera, C.M.C. [Laboratorio de Peliculas Delgadas, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina)]. E-mail: cvera@fi.uba.ar; Aragon, R. [Laboratorio de Peliculas Delgadas, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina); CINSO, CONICET, CITEFA, Lasalle 4397, Villa Martelli, Buenos Aires (Argentina)

    2005-07-25

    Impedance spectroscopy of fine grained (<10 {mu}m) {gamma}'-Bi{sub 2}MoO{sub 6} samples, in the frequency range of 0.1 Hz-250 kHz, relevant to sensor applications, up to 800 deg. C, has been used to characterize grain boundary and grain interior contributions to conduction. Above 500 deg. C, the grain boundary contribution is no longer rate limiting and conduction is dominated by the grain interior component. The corresponding activation energies are 0.98 eV for grain boundary and 0.73 eV for grain interior components. The weak dependence of conductivity on oxygen partial pressure below 500 deg. C can be attributed to electrode-electrolyte interface phenomena, whereas the robust response to ethanol is commensurate with changes in intrinsic ionic conductivity.

  2. Origins of Shear Jamming for Frictional Grains

    Science.gov (United States)

    Wang, Dong; Zheng, Hu; Ren, Jie; Dijksman, Joshua; Bares, Jonathan; Behringer, Robert

    2016-11-01

    Granular systems have been shown to be able to behave like solids, under shear, even when their densities are below the critical packing fraction for frictionless isotropic jamming. To understand such a phenomena, called shear jamming, the question we address here is: how does shear bring a system from a unjammed state to a jammed state, where the coordination number, Z, is no less than 3, the isotropic jamming point for frictional grains? Since Z can be used to distinguish jammed states from unjammed ones, it is vital to understand how shear increases Z. We here propose a set of three particles in contact, denoted as a trimer, as the basic unit to characterize the deformation of the system. Trimers, stabilized by inter-grain friction, fail under a certain amount of shear and bend to make extra contacts to regain stability. By defining a projection operator of the opening angle of the trimer to the compression direction in the shear, O, we see a systematically linear decrease of this quantity with respect to shear strain, demonstrating the bending of trimers as expected. In addition, the average change of O from one shear step to the next shows a good collapse when plotted against Z, indicating a universal behavior in the process of shear jamming. We acknowledge support from NSF DMR1206351, NASA NNX15AD38G, the William M. Keck Foundation and a RT-MRSEC Fellowship.

  3. Equilibrium behavior of coarse-grained chaos

    Science.gov (United States)

    Egolf, David A.; Ballard, Christopher C.; Esty, C. Clark

    2015-03-01

    A wide variety of systems exhibiting spatiotemporal chaos have been shown to be extensive, in that their fractal dimensions grow linearly with volume. Ruelle argued that this extensivity is evidence that these systems can be viewed as a gas of weakly-interacting regions. We have tested this idea by performing large-scale computational studies of spatiotemporal chaos in the 1D complex Ginzburg-Landau equation, and we have found that aspects of the coarse-grained system are well-described not only as a gas, but as an equilibrium gas -- in particular, a Tonks gas (and variants) in the grand canonical ensemble. Furthermore, for small system sizes, the average number of particles in the corresponding Tonks gas exhibits oscillatory, decaying deviations from extensivity in agreement with deviations in the fractal dimension found by Fishman and Egolf. This result not only supports Ruelle's picture but also suggests that the coarse-grained behavior of this far-from-equilibrium system might be understood using equilibrium statistical mechanics.

  4. Coarse graining flow of spin foam intertwiners

    CERN Document Server

    Dittrich, Bianca; Seth, Cameron J; Steinhaus, Sebastian

    2016-01-01

    Simplicity constraints play a crucial role in the construction of spin foam models, yet their effective behaviour on larger scales is scarcely explored. In this article we introduce intertwiner and spin net models for the quantum group $\\text{SU}(2)_k \\times \\text{SU}(2)_k$, which implement the simplicity constraints analogous to 4D Euclidean spin foam models, namely the Barrett-Crane (BC) and the Engle-Pereira-Rovelli-Livine/Freidel-Krasnov (EPRL/FK) model. These models are numerically coarse grained via tensor network renormalization, allowing us to trace the flow of simplicity constraints to larger scales. In order to perform these simulations we have substantially adapted tensor network algorithms, which we discuss in detail. The BC and the EPRL/FK model behave very differently under coarse graining: While the unique BC intertwiner model is a fixed point and therefore constitutes a 2D topological phase, BC spin net models flow away from the initial simplicity constraints and converge to several different ...

  5. Grain Exchange Probabilities Within a Gravel Bed

    Science.gov (United States)

    Haschenburger, J.

    2008-12-01

    Sediment transfers in gravel-bed rivers involve the vertical exchange of sediments during floods. These exchanges regulate the virtual velocity of sediment and bed material texture. This study describes general tendencies in the vertical exchange of gravels within the substrate that result from multiple floods. Empirical observations come from Carnation Creek, a small gravel-bed river with large woody debris located on the west coast of Vancouver Island, British Columbia. Frequent floods and the relatively limited armor layer facilitate streambed activity and relatively high bedload transport rates, typically under partial sediment transport conditions. Over 2000 magnetically tagged stones, ranging in size from 16 to 180 mm, were deployed on the bed surface between 1991 and 1992. These tracers have been recovered 10 times over 12 flood seasons to quantify their vertical position in the streambed. For analysis, the bed is divided into layers based on armor layer thickness. Once tracers are well mixed within the streambed, grains in the surface layer are most likely to be mixed into the subsurface, while subsurface grains are most likely to persist within the subsurface. Fractional exchange probabilities approach size independence when the most active depth of the substrate is considered. Overall these results highlight vertical mixing as an important process in the dispersion of gravels.

  6. A coarse-grained spectral signature generator

    Science.gov (United States)

    Lam, K. P.; Austin, J. C.; Day, C. R.

    2007-01-01

    This paper investigates the method for object fingerprinting in the context of element specific x-ray imaging. In particular, the use of spectral descriptors that are illumination invariant and viewpoint independent for pattern identification was examined in some detail. To improve generating the relevant "signature", the spectral descriptor constructed is enhanced with a differentiator which has built-in noise filtration capability and good localisation properties, thus facilitating the extraction of element specific features at a coarse-grained level. In addition to the demonstrable efficacy in identifying significant image intensity transitions that are associated with the underlying physical process of interest, the method has the distinct advantage of being conceptually simple and computationally efficient. These latter properties allow the descriptor to be further utilised by an intelligent system capable of performing a fine-grained analysis of the extracted pattern signatures. The performance of the spectral descriptor has been studied in terms of the quality of the signature vectors that it generated, quantitatively based on the established framework of Spectral Information Measure (SIM). Early results suggested that such a multiscale approach of image sequence analysis offers a considerable potential for real-time applications.

  7. Coarse grained model of entangled polymer melts

    Science.gov (United States)

    Rakshit, Abhik

    A coarse graining procedure aimed at reproducing both the chain structure and dynamics in entangled polymeric melts is presented. The reference, fine scale system is a beadspring-type representation of the melt. This model is used to calibrate the coarse model for a specific monodisperse melt of linear chains. The coarse model is then used to represent the structure and dynamics of various other systems in thermodynamic equilibrium and non-equilibrium. Extensive comparison with equivalent fine scale models is performed to verify the coarse model. The level of coarse graining is selected equal to the number of beads in the entanglement segment, Ne. The coarse model is discrete and contains blobs each representing Ne consecutive beads in the fine scale model. The mapping is defined by the following conditions: the probability of given state of the coarse system is equal to that of all fine system states compatible with the respective coarse state, the dissipation per coarse grained object is similar in the two systems, constraints to the motion of a representative chain exist in the fine phase space and the coarse phase space is adjusted such to capture them. Specifically, the chain inner blobs are constrained to move along the backbone of the coarse grained chain, while the end blobs move in the 3D embedding space. The end blobs continuously re-define the diffusion path for the inner blobs. The input parameters governing the dynamics of the coarse grained system are calibrated based on the fine scale model behavior. These are the characteristic length scale, Ne, and the effective friction coefficient per coarse grained object. Although the coarse model cannot reproduce the whole thermodynamics of the fine system, it ensures that the pair and end-to-end distribution functions, the rate of relaxation of segmental and end-to-end vectors, the Rouse modes and the diffusion dynamics are properly represented. The model intrinsically captures contour length fluctuations and

  8. Transmission Electron Microscopy of Itokawa Regolith Grains

    Science.gov (United States)

    Keller, Lindsay P.; Berger, E. L.

    2013-01-01

    Introduction: In a remarkable engineering achievement, the JAXA space agency successfully recovered the Hayabusa space-craft in June 2010, following a non-optimal encounter and sur-face sampling mission to asteroid 25143 Itokawa. These are the first direct samples ever obtained and returned from the surface of an asteroid. The Hayabusa samples thus present a special op-portunity to directly investigate the evolution of asteroidal sur-faces, from the development of the regolith to the study of the effects of space weathering. Here we report on our preliminary TEM measurements on two Itokawa samples. Methods: We were allocated particles RA-QD02-0125 and RA-QD02-0211. Both particles were embedded in low viscosity epoxy and thin sections were prepared using ultramicrotomy. High resolution images and electron diffraction data were ob-tained using a JEOL 2500SE 200 kV field-emission scanning-transmission electron microscope. Quantitative maps and anal-yses were obtained using a Thermo thin-window energy-dispersive x-ray (EDX) spectrometer. Results: Both particles are olivine-rich (Fo70) with µm-sized inclusions of FeS and have microstructurally complex rims. Par-ticle RA-QD02-0125 is rounded and has numerous sub-µm grains attached to its surface including FeS, albite, olivine, and rare melt droplets. Solar flare tracks have not been observed, but the particle is surrounded by a continuous 50 nm thick, stuctur-ally disordered rim that is compositionally similar to the core of the grain. One of the surface adhering grains is pyrrhotite show-ing a S-depleted rim (8-10 nm thick) with nanophase Fe metal grains (<5 nm) decorating the outermost surface. The pyrrhotite displays a complex superstructure in its core that is absent in the S-depleted rim. Particle RA-QD02-0211 contains solar flare particle tracks (2x109 cm-2) and shows a structurally disordered rim 100 nm thick. The track density corresponds to a surface exposure of 103-104 years based on the track production rate

  9. Cometary Refractory Grains: Interstellar and Nebular Sources

    Science.gov (United States)

    Wooden, D. H.

    2008-07-01

    Comets are heterogeneous mixtures of interstellar and nebular materials. The degree of mixing of interstellar sources and nebular sources at different nuclear size scales holds the promise of revealing how cometary particles, cometesimals, and cometary nuclei accreted. We can ascribe cometary materials to interstellar and nebular sources and see how comets probe planet-forming process in our protoplanetary disk. Comets and cometary IDPs contain carbonaceous matter that appears to be either similar to poorly-graphitized (amorphous) carbon, a likely ISM source, or highly labile complex organics, with possible ISM or outer disk heritage. The oxygen fugacity of the solar nebula depends on the dynamical interplay between the inward migration of carbon-rich grains and of icy (water-rich) grains. Inside the water dissociation line, OH- reacts with carbon to form CO or CO2, consuming available oxygen and contributing to the canonical low oxygen fugacity. Alternatively, the influx of water vapor and/or oxygen rich dust grains from outer (cooler) disk regions can raise the oxygen fugacity. Low oxygen fugacity of the canonical solar nebula favors the condensation of Mg-rich crystalline silicates and Fe-metal, or the annealing of Fe-Mg amorphous silicates into Mg-rich crystals and Fe-metal via Fe-reduction. High oxygen fugacity nebular conditions favors the condensation of Fe-bearing to Fe-rich crystalline silicates. In the ISM, Fe-Mg amorphous silicates are prevalent, in stark contrast to Mg-rich crystalline silicates that are rare. Hence, cometary Mg-rich crystalline silicates formed in the hot, inner regions of the canonical solar nebula and they are the touchstone for models of the outward radial transport of nebular grains to the comet-forming zone. Stardust samples are dominated by Mg-rich crystalline silicates but also contain abundant Fe-bearing and Fe-rich crystalline silicates that are too large (≫0.1 μm) to be annealed Fe-Mg amorphous silicates. By comparison

  10. Measurement and Simulation of Grain Size in Strong Textured and Coarse-Grained Metal Sheets

    Institute of Scientific and Technical Information of China (English)

    Leng CHEN; Weimin MAO; Yongning YU; Huiping FENG

    2003-01-01

    An X-ray diffractometer that equipped with a two-dimensional detector is used for developing the technique of grainsize measurement for strong textured and coarse-grained Si steel sheet. The method is based on the concept thatthe position of diffraction s

  11. Relating optical and microwave grain metrics of snow: the relevance of grain shape

    Science.gov (United States)

    Krol, Quirine; Löwe, Henning

    2016-11-01

    Grain shape is commonly understood as a morphological characteristic of snow that is independent of the optical diameter (or specific surface area) influencing its physical properties. In this study we use tomography images to investigate two objectively defined metrics of grain shape that naturally extend the characterization of snow in terms of the optical diameter. One is the curvature length λ2, related to the third-order term in the expansion of the two-point correlation function, and the other is the second moment μ2 of the chord length distributions. We show that the exponential correlation length, widely used for microwave modeling, can be related to the optical diameter and λ2. Likewise, we show that the absorption enhancement parameter B and the asymmetry factor gG, required for optical modeling, can be related to the optical diameter and μ2. We establish various statistical relations between all size metrics obtained from the two-point correlation function and the chord length distribution. Overall our results suggest that the characterization of grain shape via λ2 or μ2 is virtually equivalent since both capture similar aspects of size dispersity. Our results provide a common ground for the different grain metrics required for optical and microwave modeling of snow.

  12. [Effects of applying selenium on selenium allocation, grain yield, and grain quality of two maize cultivars].

    Science.gov (United States)

    Hao, Yu-Bo; Liu, Hua-Lin; Ci, Xiao-Ke; An, Hong-Ming; Shu-Ting, Dong; Zhang, Ji-Wang; Liu, Peng; Zhao, Bin

    2012-02-01

    A pot experiment with conventional maize cultivar ZD958 and glutinous maize cultivar JN218 was conducted to study the effects of applying different concentrations (0, 10, 25 and 50 mg x kg(-1)) of selenium (Se) on the Se allocation in plant organs, grain yield, and its quality. At low concentrations (x kg(-1)), Se stimulated maize growth, and increased biomass accumulation and grain yield significantly. At high concentrations (> 25 mg x kg(-1)), Se inhibited maize growth, and decreased dry mass accumulation, grain yield, and its quality. The Se concentration in plant organs was in the order of root > leaf > stalk > sheath. The Se concentrations in plant organs had a positive correlation with the Se concentration in soil. Comparing with ZD958, JN218 could accumulate more Se in natural low-Se environment, but enrich lesser Se in the environment with 10 mg x kg(-1) of Se. Taking the Se accumulation amount in grain and aboveground vegetative organs as the standard for evaluation, JN218 was more available planted on natural low-Se (0.25 mg x kg(-1)) soil or high-Se (25 mg x kg(-1)) soil, while ZD958 was appropriate planted on Se-rich (10 mg x kg(-1)) soil or Se-polluted (50 mg x kg(-1)) soil.

  13. China’s grain production: status and prospects

    Institute of Scientific and Technical Information of China (English)

    姜长云; 张晓敏; 张艳平

    2009-01-01

    In this paper, we first look back at China’s grain production since reform and opening up and review the main factors of grain production at different stages. Secondly we find that the improvement of the per unit yield has become a major factor in the increase of grain production, and that corn has become a major grain production support variety; compared with the other varieties, paddy rice is most vulnerable in production; grain production has increasingly become dependant on scientific and technological progress and the role of infrastructure. Thirdly, the transformation of low-yielding fields in the future, the development of reserve land resources and acceleration of scientific and technological progress – these factors together promote China’s great potential for grain production; but through adjusting variety structure to promote grain production is nearly impossible. Finally, the main constraints of China’s future grain production are as follows: reduction of arable land and water shortages is becoming increasingly constrained; agricultural comparative advantage is low; opportunity cost is high and accelerating at the same time; and the uncertainties of (1) whether the agricultural inputs by government at all levels of can significantly increase the intensity; (2) whether support of the reform of grain production and systems can achieve breakthrough; and (3) whether the risk of the development of grain production can be effectively prevented. On this basis, we draw the relevant conclusions and policy recommendations.

  14. Grain Accumulation of Selenium Species in Rice (Oryza sativa L.)

    Energy Technology Data Exchange (ETDEWEB)

    Carey, Anne-Marie; Scheckel, Kirk G.; Lombi, Enzo; Newville, Matt; Choi, Yongseong; Norton, Gareth J.; Price, Adam H.; Meharg, Andrew A. (EPA); (U. South Australia); (Aberdeen); (UC)

    2012-09-05

    Efficient Se biofortification programs require a thorough understanding of the accumulation and distribution of Se species within the rice grain. Therefore, the translocation of Se species to the filling grain and their spatial unloading were investigated. Se species were supplied via cut flag leaves of intact plants and excised panicle stems subjected to a {+-} stem-girdling treatment during grain fill. Total Se concentrations in the flag leaves and grain were quantified by inductively coupled plasma mass spectrometry. Spatial accumulation was investigated using synchrotron X-ray fluorescence microtomography. Selenomethionine (SeMet) and selenomethylcysteine (SeMeSeCys) were transported to the grain more efficiently than selenite and selenate. SeMet and SeMeSeCys were translocated exclusively via the phloem, while inorganic Se was transported via both the phloem and xylem. For SeMet- and SeMeSeCys-fed grain, Se dispersed throughout the external grain layers and into the endosperm and, for SeMeSeCys, into the embryo. Selenite was retained at the point of grain entry. These results demonstrate that the organic Se species SeMet and SeMeSeCys are rapidly loaded into the phloem and transported to the grain far more efficiently than inorganic species. Organic Se species are distributed more readily, and extensively, throughout the grain than selenite.

  15. Reducing arsenic accumulation in rice grain through iron oxide amendment.

    Science.gov (United States)

    Farrow, Eric M; Wang, Jianmin; Burken, Joel G; Shi, Honglan; Yan, Wengui; Yang, John; Hua, Bin; Deng, Baolin

    2015-08-01

    Effects of soil-arsenic (As), phosphorus and iron oxide on As accumulation in rice grain were investigated. Cultivars that have significantly different sensitivity to As, straighthead-resistant Zhe 733 and straighthead-susceptible Cocodrie, were used to represent different cultivar varieties. The grain accumulation of other elements of concern, selenium (Se), molybdenum (Mo), and cadmium (Cd) was also monitored. Results demonstrated that high soil-As not only resulted in high grain-As, but could also result in high grain-Se, and Zhe 733 had significantly less grain-As than Cocodrie did. However, soil-As did not impact grain-Mo and Cd. Among all elements monitored, iron oxide amendment significantly reduced grain-As for both cultivars, while the phosphate application only reduced grain-Se for Zhe 733. Results also indicated that cultivar type significantly impacted grain accumulation of all monitored trace elements. Therefore, applying iron oxide to As-contaminated land, in addition to choosing appropriate rice cultivar, can effectively reduce the grain accumulation of As.

  16. Consumption of whole grains in French children, adolescents and adults.

    Science.gov (United States)

    Bellisle, France; Hébel, Pascale; Colin, Justine; Reyé, Béatrice; Hopkins, Sinead

    2014-11-28

    The consumption of whole grain foods is associated with many nutritional, health and weight control benefits. The present study assessed whole grain intake in France on the basis of a 7 d dietary survey in a representative sample of children, adolescents and adults (Comportements et Consommations Alimentaires en France 2010 survey). Special care was taken to identify and assess the intake of all whole grains. All foods consumed were considered, with no lower limit on whole grain content. For the majority of foods, details regarding the whole grain contents were obtained from brand information and quantitative nutrient declarations on food labels. Over half of the respondents reported never consuming any whole grain. In participants who did, consumption levels were very low (about 9·1 g/d in children and 14·4 g/d in adults). The main food sources of whole grains were breakfast cereals in children and adolescents and bread in adults. Consumers of whole grains had higher daily intakes of fibre and several vitamins and minerals than non-consumers. In adults but not in children, the OR for overweight/obesity decreased significantly as the level of whole grain consumption increased. Although a majority of French consumers comply with the national recommendation to consume a starchy food with each meal, they do so with minimal consumption of whole grain foods.

  17. Airtight storage of moist wheat grain improves bioethanol yields

    Directory of Open Access Journals (Sweden)

    Piens Kathleen

    2009-08-01

    Full Text Available Abstract Background Drying is currently the most frequently used conservation method for cereal grain, which in temperate climates consumes a major part of process energy. Airtight storage of moist feed grain using the biocontrol yeast Pichia anomala as biopreservation agent can substantially reduce the process energy for grain storage. In this study we tested the potential of moist stored grain for bioethanol production. Results The ethanol yield from moist wheat was enhanced by 14% compared with the control obtained from traditionally (dry stored grain. This enhancement was observed independently of whether or not P. anomala was added to the storage system, indicating that P. anomala does not impair ethanol fermentation. Starch and sugar analyses showed that during pre-treatment the starch of moist grain was better degraded by amylase treatment than that of the dry grain. Additional pre-treatment with cellulose and hemicellulose-degrading enzymes did not further increase the total ethanol yield. Sugar analysis after this pre-treatment showed an increased release of sugars not fermentable by Saccharomyces cerevisiae. Conclusion The ethanol yield from wheat grain is increased by airtight storage of moist grain, which in addition can save substantial amounts of energy used for drying the grain. This provides a new opportunity to increase the sustainability of bioethanol production.

  18. Activation energies of grain growth mechanisms in aluminum coatings

    Energy Technology Data Exchange (ETDEWEB)

    Jankowski, Alan [Lawrence Livermore National Laboratory, Chemistry and Materials Science, CA (United States)]. E-mail: jankowski1@11nl.gov; Ferreira, James [Lawrence Livermore National Laboratory, Chemistry and Materials Science, CA (United States); Hayes, Jeffrey [Lawrence Livermore National Laboratory, Mechanical Engineering, Livermore, CA 94551-9900 (United States)

    2005-11-22

    To produce a specific grain size in metallic coatings requires precise control of the time at temperature during the deposition process. Aluminum coatings are deposited using electron-beam evaporation onto heated substrate surfaces of both mica and lithium flouride. The grain size of the coating is determined upon examination of the microstructure in plan view and cross-section. Ideal grain growth is observed over the entire experimental range of temperature examined from 413 to 843 K. A transition in the activation energy for grain growth from 0.87 to 2.04 eV atom{sup -1} is observed as the temperature increases from < 526 K to > 588 K. The transition is indicative of the dominant mechanism for grain growth shifting with increasing temperature from grain boundary to lattice diffusion.

  19. The bio refinery; producing feed and fuel from grain.

    Science.gov (United States)

    Scholey, D V; Burton, E J; Williams, P E V

    2016-04-15

    It is both possible and practicable to produce feed and fuel from grain. Using the value of grain to produce renewable energy for transport, while using the remaining protein content of the grain as a valuable protein source for livestock and for fish, can be seen as a complimentary and optimal use of all the grain constituents. Consideration must be given to maximise the value of the yeast components, as substantial yeast is generated during the fermentation of the grain starch to produce ethanol. Yeast is a nutritionally rich feed ingredient, with potential for use both as feed protein and as a feed supplement with possible immunity and gut health enhancing properties. Bioprocessing, with the consequent economies of scale, is a process whereby the value of grain can be optimised in a way that is traditional, natural and sustainable for primarily producing protein and oil for feed with a co-product ethanol as a renewable fuel.

  20. Effects and mechanisms of grain refinement in aluminium alloys

    Indian Academy of Sciences (India)

    K T Kashyap; T Chandrashekar

    2001-08-01

    Grain refinement plays a crucial role in improving characteristics and properties of cast and wrought aluminium alloys. Generally Al–Ti and Al–Ti–B master alloys are added to the aluminium alloys to grain refine the solidified product. The mechanism of grain refinement is of considerable controversy in the scientific literature. The nucleant effects i.e. which particle and its characteristics nucleate -Al, has been the subject of intensive research. Lately the solute effect i.e. the effect of dissolved titanium on grain refinement, has come into forefront of grain refinement research. The present paper attempts to review the literature on the nucleant effects and solute effects on grain refinement and addresses the importance of dissolved titanium in promoting nucleation of -Al on nucleant particles.

  1. Microstructural stability of ultrafine grained cold sprayed 6061 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Rokni, M.R., E-mail: mohammadreza.rokni@mines.sdsmt.edu [Department of Materials and Metallurgical Engineering, Advanced Materials Processing Center, South Dakota School of Mines and Technology (SDSM and T), SD (United States); Widener, C.A. [Department of Materials and Metallurgical Engineering, Advanced Materials Processing Center, South Dakota School of Mines and Technology (SDSM and T), SD (United States); Champagne, V.R. [U.S. Army Research Laboratory, Weapons and Materials Research Directorate, Aberdeen Proving Ground, MD (United States)

    2014-01-30

    The microstructural stability of ultrafine grained (UFG) cold spray 6061 aluminum deposits produced by high pressure cold spray were investigated by in situ heating to a fully annealed state via a hot-stage transmission electron microscope (TEM). It was possible to observe the precise locations and temperatures of different microstructural changes, like dislocation movement and other restoration processes. Even after heating up to the annealing temperature for this alloy, the deposited layer in the perpendicular direction was found to preserve the UFG structures, which were the result of different recrystallization mechanisms caused by the high strains present during cold spraying. Extensive solute segregation at the grain boundaries acted as an obstruction for grain boundary migration in this direction, thereby preventing grain growth. However, in the direction parallel to the deposited surface, the UFGs were not resistant to grain coursing like the other direction, since the grain boundaries had much less solute segregation.

  2. Grain Alignment: Role of Radiative Torques and Paramagnetic Relaxation

    CERN Document Server

    Lazarian, A; Hoang, Thiem

    2015-01-01

    Polarization arising from aligned dust grains presents a unique opportunity to study magnetic fields in the diffuse interstellar medium and molecular clouds. Polarization from circumstellar regions, accretion disks and comet atmospheres can also be related to aligned dust.To reliably trace magnetic fields quantitative theory of grain alignment is required. Formulating the theory that would correspond to observations was one of the longstanding problems in astrophysics. Lately this problem has been successfully addressed and in this review we summarize some of the most important theoretical advances in the theory of grain alignment by radiative torques (RATs) that act on realistic irregular dust grains. We discuss an analytical model of RATs and the ways to make RAT alignment more efficient, e.g. through paramagnetic relaxation when grains have inclusions with strong magnetic response. For very small grains for which RAT alignment is inefficient, we also discuss paramagnetic relaxation and a process termed res...

  3. Kinetic constants of abnormal grain growth in nanocrystalline nickel

    Science.gov (United States)

    Aleshin, A. N.

    2016-02-01

    The grain growth in nanocrystalline nickel with a purity of 99.5 at % during non-isothermal annealing was experimentally investigated using differential scanning calorimetry and transmission electron microscopy. Nanocrystalline nickel was prepared by electrodeposition and had an average grain size of approximately 20 nm. It was shown that, at a temperature corresponding to the calorimetric signal peak, abnormal grain growth occurs with the formation of a bimodal grain microstructure. Calorimeters signals were processed within the Johnson-Mehl-Avrami formalism. This made it possible to determine the exponent of the corresponding equation, the frequency factor, and the activation energy of the grain growth, which was found to be equal to the activation energy of the vacancy migration. The reasons for the abnormal grain growth in nanocrystalline nickel were discussed.

  4. Modification of computer simulation of normal grain growth

    Institute of Scientific and Technical Information of China (English)

    李剑; 李世晨; 郑子樵; 刘祖耀; 陈大钦

    2004-01-01

    A set of principles on transition probability was supplied for the physical process of grain growth. In accord with these principles, a modified transition probability considering the influence of temperature was put forward to simulate the normal grain growth relying on temperature and second phase particles. The modified transition probability correctly reflects the dependence of grain growth on the temperature. The effect of different shapes of second phase particles on the grain growth process was taken into account using the modified transition probability.The relationship between the area fraction of second phase particles and the limit of grain size of the matrix was given. The microstructural evolution patterns employed to 2-D were given. The results agree well with the real grain growth process. All these suggest that the modified transition probability is better than the conventional one.

  5. Subset Feature Learning for Fine-Grained Category Classification

    OpenAIRE

    Ge, Zongyuan; McCool, Christopher; Sanderson, Conrad; Corke, Peter

    2015-01-01

    Fine-grained categorisation has been a challenging problem due to small inter-class variation, large intra-class variation and low number of training images. We propose a learning system which first clusters visually similar classes and then learns deep convolutional neural network features specific to each subset. Experiments on the popular fine-grained Caltech-UCSD bird dataset show that the proposed method outperforms recent fine-grained categorisation methods under the most difficult sett...

  6. ON THE QUESTION OF PROCESS CONTROL COMBINED GRAIN DRYING

    Directory of Open Access Journals (Sweden)

    Valentina Afonkina

    2016-03-01

    Full Text Available A large part of the grain produced in the South Urals has high humidity and needs to be dried before storage. Drying is an energy-intensive process and is about 70 % of the total energy consumption for post-harvest processing of grain. Modern grain drying equip¬ment, implements high-convection drying, and heat provides cost 5 350–5 500 kJ per 1 kg of evaporated moisture, which is well above the theoretical calculations. Combined drying, which involves high-temperature drying step and aeration enables to reduce heat costs up to 30 %. To control the combined drying process it is necessary that final grain moisture relates to such parameters of high-temperature drying and aeration as the initial moisture content, the temperature of grain and the time subsequent aering. The paper describes the said relation as a mathematical model of the second order obtained experi¬mentally for wheat. The model has been derived from the implementation of Box-Benkin plan for three factors – the initial grain moisture, temperature and time of grain heating and aering. The experiment was conducted for a 200 mm thick fixed grain bed. We also have got a model relating energy consumption to the said parameters. The model of the final grain moisture within the variation of factors can be used to create a control algorithm for combined drying. Taking as the set parameters final moisture, initial moisture and grain heating temperature, a microcontroller calculates the time for active aering necessary to obtain final grain moisture and an unloading mechanism provides the necessary time through regulating the discharge rate. The model makes it possible to calculate the energy usage for drying at different values of initial moisture, temperature and time of grain heating and aering.

  7. Nano-Sized Grain Refinement Using Friction Stir Processing

    Science.gov (United States)

    2013-03-01

    friction stir weld is a very fine grain microstructure produced as a result of dynamic recrystallization. The friction stir ... Friction Stir Processing, Magnesium, Nano-size grains Abstract A key characteristic of a friction stir weld is a very fine grain microstructure...state process developed on the basis of the friction stir welding (FSW) technique invented by The Welding Institute (TWI) in 1991 [2]. During

  8. Dust extinction and absorption: the challenge of porous grains

    OpenAIRE

    Voshchinnikov, N. V.; Il'in, V. B.; Henning, Th.; Dubkova, D. N.

    2005-01-01

    In many models of dusty objects in space the grains are assumed to be composite or fluffy. However, the computation of the optical properties of such particles is still a very difficult problem. We analyze how the increase of grain porosity influences basic features of cosmic dust -- interstellar extinction, dust temperature, infrared bands and millimeter opacity. Porous grains can reproduce the flat extinction across the $3 - 8 \\mkm$ wavelength range measured for several lines of sight by {\\...

  9. Complicated hollow turbine blades and surface grain refinement process

    OpenAIRE

    Peng Zhijiang; Jia Shuqin; Zhang Zehai

    2010-01-01

    The control of grain size in superalloys is critical in the manufacture of gas turbine blades. The aim of the present research is to provide the technology for producing complicated hollow turbine blades with fine surface grains and better comprehensive mechanical properties. By melt superheating treatment and coating the internal surfaces of shell mould using a cobalt aluminate-bearing coating material, the influence of cobalt aluminate as inoculant on the surface grain sizes of turbine blad...

  10. Consumer Knowledge, Food Label Use and Grain Consumption

    OpenAIRE

    Lin, Biing-Hwan; Yen, Steven T.

    2005-01-01

    Responding to mounting evidence of the association between whole-grain consumption and a reduced risk of heart problems and other diseases as well as body weight maintenance, the U.S. Government has strongly encouraged its citizens to increase consumption of whole grains. However, compared against the 2005 Federal dietary recommendations, in 1994-96 only 6 percent of Americans met the current recommended whole-grain consumption. To narrow this huge gap between actual and recommended consumpti...

  11. A Simple Method for Grain Refinement of Pure Aluminium

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In order to produce the fully equiaxed and fine grained pure Al, a simple casting process that used cooling slope was examined and compared with conventional casting process under same casting conditions. By using cooling slope,grains over the whole section of castings were suddenly refined and ability of grain refinement kept up at very high mold temperature up to 550℃ in examined casting conditions.

  12. Adaptive Coarse Graining, Environment, Strong Decoherence, and Quasiclassical Realms

    CERN Document Server

    Gell-Mann, Murray

    2013-01-01

    Three ideas are introduced that when brought together characterize the realistic quasiclassical realms of our quantum universe as particular kinds of sets of alternative coarse-grained histories defined by quasiclassical variables: (1) Branch dependent adaptive coarse grainings that can be close to maximally refined and can simplify calculation. (2) Narrative coarse grainings that describe how features of the universe change over time and allow the construction of an environment. (3) A notion of strong decoherence that characterizes realistic mechanisms of decoherence.

  13. Bioethanol production from germinated grain by inherent enzymes

    OpenAIRE

    Kádár, Zsófia; Christensen, Anne Deen; Thomsen, Mette Hedegaard; Thomsen, Anne Belinda

    2009-01-01

    The malting in brewing process develops enzymes that are required to hydrolyze the complex starch in grain into simple fermentable sugars. These proceed the three following steps: Steeping encourages germination to start, germination prepares the conversion of the starch to sugars, and kilning stops the germination. In this study, a method for bioethanol production from rye grain was developed by utilizing the inherent amylase activity from germination of the seed. Grain germination was pe...

  14. Toxigenicity of fungi from grain sorghum.

    Science.gov (United States)

    Diener, U L; Morgan-Jones, G; Wagener, R E; Davis, N D

    1981-07-10

    The mycoflora of nine varieties of grain sorghum was determined by plating serial dilutions of ground samples on rose bengal-streptomycin agar. Seventeen species of fungi representing 10 genera were identified. Curvularia, Penicillium, Mucor, and Aspergillus were dominant genera. Extracts of P. herquei were highly toxic to brine shrimp, while those of C. clavata, C. lunata, and Mucor mucedo showed low to moderate toxicity. Extracts of C. clavata, C. lunata, and M. mucedo were highly toxic to chicken embryos; those of six other species showed low to moderate toxicity. Extracts of C. clavata, C. lunata, M. mucedo, Fusarium moniliforme, Alternaria tenuissima. P. herquei, and P. steckii showed varying degrees of toxicity to day-old cockerels.

  15. Coarse graining in spin foam models

    Energy Technology Data Exchange (ETDEWEB)

    Markopoulou, Fotini

    2003-03-07

    We formulate the problem of finding the low-energy limit of spin foam models as a coarse-graining problem in the sense of statistical physics. This suggests that renormalization group methods may be used to find that limit. However, since spin foams are models of spacetime at the Planck scale, novel issues arise: these microscopic models are sums over irregular, background-independent lattices. We show that all of these issues can be addressed by the recent application of the Kreimer Hopf algebra for quantum field theory renormalization to non-perturbative statistical physics. The main difference from the standard renormalization group is that the Hopf algebra executes block transformations in parts of the lattice only but in a controlled manner so that the end result is a fully block-transformed lattice.

  16. Optical Properties of Complex Dust Grains

    CERN Document Server

    Andersen, A C; Niklasson, G A; Pustovit, V N

    2004-01-01

    Dust particles in space may appear as clusters of individual grains. The morphology of these clusters could be of a fractal or more compact nature. To investigate how the cluster morphology influences the calculated extinction of different clusters in the wavelength range 0.1 - 100 micron, we have preformed extinction calculations of three-dimensional clusters consisting of identical touching spherical particles arranged in three different geometries: prefractal, simple cubic and face-centered cubic. In our calculations we find that the extinction of prefractal and compact clusters are of the same order of magnitude. For the calculations, we have performed an in-depth comparison of the theoretical predictions of extinction coefficients of multi-sphere clusters derived by rigorous solutions, on the one hand, and popular discrete-dipole approximations, on the other. This comparison is essential if one is to assess the degree of reliability of model calculations made with the discrete-dipole approximations, whic...

  17. Dust grains from the heart of supernovae

    Science.gov (United States)

    Bocchio, M.; Marassi, S.; Schneider, R.; Bianchi, S.; Limongi, M.; Chieffi, A.

    2016-03-01

    Dust grains are classically thought to form in the winds of asymptotic giant branch (AGB) stars. However, there is increasing evidence today for dust formation in supernovae (SNe). To establish the relative importance of these two classes of stellar sources of dust, it is important to know the fraction of freshly formed dust in SN ejecta that is able to survive the passage of the reverse shock and be injected in the interstellar medium. With this aim, we have developed a new code, GRASH_Rev, that allows following the dynamics of dust grains in the shocked SN ejecta and computing the time evolution of the mass, composition, and size distribution of the grains. We considered four well-studied SNe in the Milky Way and Large Magellanic Cloud: SN 1987A, CasA, the Crab nebula, and N49. These sources have been observed with both Spitzer and Herschel, and the multiwavelength data allow a better assessment the mass of warm and cold dust associated with the ejecta. For each SN, we first identified the best explosion model, using the mass and metallicity of the progenitor star, the mass of 56Ni, the explosion energy, and the circumstellar medium density inferred from the data. We then ran a recently developed dust formation model to compute the properties of freshly formed dust. Starting from these input models, GRASH_Rev self-consistently follows the dynamics of the grains, considering the effects of the forward and reverse shock, and allows predicting the time evolution of the dust mass, composition, and size distribution in the shocked and unshocked regions of the ejecta. All the simulated models aagree well with observations. Our study suggests that SN 1987A is too young for the reverse shock to have affected the dust mass. Hence the observed dust mass of 0.7-0.9 M⊙ in this source can be safely considered as indicative of the mass of freshly formed dust in SN ejecta. Conversely, in the other three SNe, the reverse shock has already destroyed between 10-40% of the

  18. Production and Recoil Loss of Cosmogenic Nuclides in Presolar Grains

    Science.gov (United States)

    Trappitsch, Reto; Leya, Ingo

    2016-05-01

    Presolar grains are small particles that condensed in the vicinity of dying stars. Some of these grains survived the voyage through the interstellar medium (ISM) and were incorporated into meteorite parent bodies at the formation of the Solar System. An important question is when these stellar processes happened, i.e., how long presolar grains were drifting through the ISM. While conventional radiometric dating of such small grains is very difficult, presolar grains are irradiated with galactic cosmic rays (GCRs) in the ISM, which induce the production of cosmogenic nuclides. This opens the possibility to determine cosmic-ray exposure (CRE) ages, i.e., how long presolar grains were irradiated in the ISM. Here, we present a new model for the production and loss of cosmogenic 3He, 6,7Li, and 21,22Ne in presolar SiC grains. The cosmogenic production rates are calculated using a state-of-the-art nuclear cross-section database and a GCR spectrum in the ISM consistent with recent Voyager data. Our findings are that previously measured 3He and 21Ne CRE ages agree within the (sometimes large) 2σ uncertainties and that the CRE ages for most presolar grains are smaller than the predicted survival times. The obtained results are relatively robust since interferences from implanted low-energy GCRs into the presolar SiC grains and/or from cosmogenic production within the meteoroid can be neglected.

  19. Austenite and ferrite grain size evolution in plain carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Militzer, M.; Giumelli, A.; Hawbolt, E.B.; Meadowcroft, T.R. [British Columbia Univ., Vancouver, BC (Canada)

    1995-01-01

    Grain size evolution in a 0.17%C, 0.74%Mn plain carbon steel is investigated using a Gleeble 1500 thermomechanical simulator. Austenite grain growth measurements in the temperature range from 900 to 1150{degrees}C have been used to validate the Abbruzzese and Luecke model, which is recommended for simulating grain growth during reheating. For run-out table conditions, the ferrite grain size decreases from 1l{mu}m to 4{mu}m when the cooling rate from the austenite is increased from 1 to 80{degrees}C/s.

  20. Steady-state grain growth in UO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Galinari, C.M.; Lameiras, F.S. [CDTN/CNEN, Belo Horizonte (Brazil)

    1998-06-05

    The authors have observed steady-state grain growth in sintered UO{sub 2} pellets of nuclear purity at 2,003 K under H{sub 2}. The behavior of the grain size distribution at different instants is consistent with the grain growth model proposed by one of the authors. The total number of grains was estimated using the Saltykov`s method, and the evolution is in accordance with the model proposed by Rhines and Craig. The parabolic growth law was observed for the mean intercept length with n = 0.4.

  1. Conditional differential cryptanalysis of 105 round Grain v1

    DEFF Research Database (Denmark)

    Banik, Subhadeep

    2016-01-01

    In this paper we propose conditional differential cryptanalysis of 105 round Grain v1. This improves the attack proposed on 97 round Grain v1 by Knellwolf et al at Asiacrypt 2010. We take the help of the tool ΔGrain KSA, to track the differential trails introduced in the internal state of Grain v1...... by any difference in the IV bits. We prove that a suitably introduced difference in the IV leads to a distinguisher for the output bit produced in the 105th round. This helps determine the values of 6 expressions in the Secret Key bits. Using the above attack as a subroutine, we propose a method...

  2. Communities of fungi in grain from several generations of triticale

    Directory of Open Access Journals (Sweden)

    Jacek Kwiatkowski

    2012-12-01

    Full Text Available An assessment of health status of winter triticale grain obtained from a longterm reproduction experiment was performed in 1993-1994. Grain from six generations of triticale was examined each year. In both years of the study, the most frequently isolated fungus was Alternaria alternata. The number of isolated pathogens as well as the total extent of grain infestation by fungi depended on the weather conditions during the vegetative growth of triticale plants. There was no correlation between the generations of triticale and fungal infestation of triticale grain.

  3. Whole-grain consumption and chronic disease: protective mechanisms.

    Science.gov (United States)

    Slavin, J; Jacobs, D; Marquart, L

    1997-01-01

    Dietary guidance recommends consumption of whole grains to reduce the risk of chronic diseases including cancer and cardiovascular disease. Epidemiologic studies support the belief that whole grains are protective against cancers, especially gastrointestinal cancers such as gastric and colonic, and cardiovascular disease. Components in whole grains that may be protective are diverse and include compounds that affect the gut environment, i.e., dietary fiber, resistant starch, and other undigestible compounds in whole grains, compounds that function as antioxidants such as trace minerals and phenolic compounds, and compounds that are phytoestrogens with potential hormonal effects. Many of the protective compounds in whole grains are also in fruits and vegetables, but some plant compounds are more concentrated in whole grains, such as phenolic compounds including ferulic and caffeic acid. Other potential mechanistic effects of whole grains include binding of carcinogens and modulation of glycemic index. Clearly, the range of protective substances in whole grains is impressive, and advice to consume additional whole grains is justifiable.

  4. Simulation of Ceramic Grain Growth in Three Dimensions

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Microstructural evolutions of ceramic grain growth at atomistic scale were modeled. The simulation was preceded with Monte-Carlo method, using Visual C++ and OpenGL languages. Realistic images in series were monitored both in two d imensions and three dimensions. Simulated image of grain growth in this series i s presented in left figure with N 0=25, r=0.40 nm, α=0.1, T=1 300 ℃, and P 0=50 %. It was seen that the average grain size increases wit h the time of grain growth. It is in good agreement with t...

  5. Radiation pressure on fluffy submicron-sized grains

    CERN Document Server

    Silsbee, Kedron

    2015-01-01

    We investigate the claim that the ratio {\\beta} of radiation pressure force to gravitational force on a dust grain in our solar system can substantially exceed unity for some grain sizes, provided that grain porosity is high enough. For model grains consisting of random aggregates of silicate spherules, we find that the maximum value of {\\beta} is almost independent of grain porosity, but for small (<0.3 {\\mu}m) grains, {\\beta} actually decreases with increasing porosity. These results affect the interpretation of the grain trajectories estimated from the Stardust mission, which were modeled assuming {\\beta} values exceeding one. We find that radiation pressure effects are not large enough for particles Orion and Hylabrook captured by Stardust to be of interstellar origin given their reported impact velocities. We also investigate the effect of metallic iron inclusions in the dust grains, and find that metallic iron will increase {\\beta}, but at least half the grain (by mass) must be iron in order to raise...

  6. Determination of grain boundary impurity effects in polycrystalline silicon

    Science.gov (United States)

    Kazmerski, L. L.; Dick, J. R.

    1984-06-01

    An analysis is made of the relationships existing between the chemistry and composition of the intergrain regions in polycrystalline silicon, the electrooptical properties of the grain boundaries, and the performance of polycrystalline Si solar cells. The following two impurity mechanisms are emphasized: segregation of oxygen to grain boundaries during heat treatments and the passivation of grain boundaries by incorporation of hydrogen. It is shown that hydrogen is localized at the defects; the effects of hydrogen localization on the electrical characteristics of the grain boundary and of the solar cell are discussed.

  7. New Process for Grain Refinement of Aluminum. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Joseph A. Megy

    2000-09-22

    A new method of grain refining aluminum involving in-situ formation of boride nuclei in molten aluminum just prior to casting has been developed in the subject DOE program over the last thirty months by a team consisting of JDC, Inc., Alcoa Technical Center, GRAS, Inc., Touchstone Labs, and GKS Engineering Services. The Manufacturing process to make boron trichloride for grain refining is much simpler than preparing conventional grain refiners, with attendant environmental, capital, and energy savings. The manufacture of boride grain refining nuclei using the fy-Gem process avoids clusters, salt and oxide inclusions that cause quality problems in aluminum today.

  8. Grain growth in Al-2% Cu thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, J.E. Jr. (Max-Planck-Institut fuer Metallforschung, Stuttgart (Germany)); Frear, D.R. (Sandia National Labs., Albuquerque, NM (United States)); Morris, J.W. Jr. (Lawrence Berkeley Lab., CA (United States))

    1991-06-01

    The grain size and grain growth kinetics in sputter deposited Al-2% Cu films on silicon substrates were determined by TEM for various film thicknesses and anneal times, temperatures and methods. Grain sizes were found to be typically lognormally distributed. The as- deposited grain size (d{sub o}) dependence on film thickness (TH) was found to be d{sub o} = C TH{sup {1/2}}, due to competitive grain growth during film formation. Annealed grain size (d) after Rapid Thermal Annealing (RTA) for time (t) at temperature (T) is described by the general equation d {minus} do = C TH{sup 0.7} {l brace}t exp ({minus}{Delta}E{sub a}/kT){r brace}{sup 1/8}, where {Delta}E{sub a} = 0.85 ev for 0.4 {mu}m films and {Delta}E{sub a} = 1.1 ev for 0.8 {mu}m films. Grain growth is largely saturated for these anneals. Grain growth is shown to be more extensive during RTA anneals than furnace annealing and more extensive in 0.4 {mu}m films than 0.8 {mu}m films for equivalent RTA cycles. The results are discussed in terms of models, simulations and previous results of grain growth in thin metal films. 21 refs., 4 figs.

  9. Barium concentration in grain of Aegilops and Triticum species

    Directory of Open Access Journals (Sweden)

    Denčić Srbislav S.

    2015-01-01

    Full Text Available The aim of this study was to evaluate the concentration of barium in grain of various Aegilops and Triticum species with different genomes. The studied species differed significantly with respect to the concentration of barium. The grain of wild diploid Aegilops speltoides, the donor of B genome, contained significantly higher Ba concentration than all other analyzed genotypes. Wild and cultivated tetraploid wheats (Triticum diciccoides, Triticum dicoccon, Triticum turgidum and Triticum durum had the lowest Ba concentration in grain. The modern cultivated hexaploid varieties presented substantial variation in grain concentration of barium. The highest Ba concentration (3.42 mg/kg occurred in Serbian winter wheat variety Panonnia.

  10. Design of zirconia grain boundaries——An exploration of the design of oxide ceramic grain boundaries

    Institute of Scientific and Technical Information of China (English)

    郭新; 袁润章

    1996-01-01

    The grain-boundary resistance of ZrO2 mainly consists of the contribution from the space-charge layers Rsc and that from the grain-boundary phase Rgbp The reduction of Rsc can be realized by the segregations of solutes with positive effective charge in the space-charge layers,while the reduction of Rgbp can be achieved by decreasing the amount of the grain-boundary phase,changing the morphology of the phase and forming grain-boundary phase with high conductivity.The best grain-boundary design effect can only be achieved by the joint design of the space-charge layers and the grain-boundary phase.

  11. A comparison between corn and grain sorghum fermentation rates, Distillers Dried Grains with Solubles composition, and lipid profiles.

    Science.gov (United States)

    Johnston, David J; Moreau, Robert A

    2017-02-01

    The aim of this study was to determine if the compositional difference between grain sorghum and corn impact ethanol yields and coproduct value when grain sorghum is incorporated into existing corn ethanol facilities. Fermentation properties of corn and grain sorghum were compared utilizing two fermentation systems (conventional thermal starch liquefaction and native starch hydrolysis). Fermentation results indicated that protease addition influenced the fermentation rate and yield for grain sorghum, improving yields by 1-2% over non-protease treated fermentations. Distillers Dried Grains with Solubles produced from sorghum had a statistically significant higher yields and significantly higher protein content relative to corn. Lipid analysis of the Distillers Dried Grains with Solubles showed statistically significant differences between corn and sorghum in triacylglycerol, diacylglycerol and free fatty acid levels.

  12. Effects of grain size and grain boundary on critical current density of high T(sub c) superconducting oxides

    Science.gov (United States)

    Zhao, Y.; Zhang, Q. R.; Zhang, H.

    1990-01-01

    By means of adding impurity elements in high T sub c oxides, the effects were studied of grain size and grain boundary on the critical current density of the following systems: YBa2Cu3O(7-y) and Bi-Pr-Sr-Ca-Cu-O. In order to only change the microstructure instead of the superconductivity of the grains in the samples, the impurity elements were added into the systems in terms of the methods like this: (1) substituting Y with the lanthanide except Pr, Ce, and Tb in YBa2Cu3O(7-y) system to finning down grains in the samples, therefore, the effect can be investigated of the grain size on the critical current density of 1:2:3 compounds; (2) mixing the high T sub c oxides with the metal elements, such as Ag, according to the composition of (high T sub c oxide)1-xAgx to metallize the grain boundaries in the samples, studying the effect of the electric conductivity of the grain boundaries on the critical current density; (3) adding SiO2, PbO2, and SnO2 into the high T sub c oxide to form impurity phases in the grain boundaries, trying to find out the effects of the impurity phases or metalloid grain boundaries on the critical current density of the high T sub c superconductors. The experimental results indicate that in the case of of the presence of the metalloid grain boundaries finning down grains fails to enhance the j sub c, but restrains it strongly, the granular high T sub c superconductors with the small size grains coupled weakly is always the low j sub c system.

  13. Method of aeration disinfecting and drying grain in bulk and pretreating seeds and a transverse blow silo grain dryer therefor

    Science.gov (United States)

    Danchenko, Vitaliy G.; Noyes, Ronald T.; Potapovych, Larysa P.

    2012-02-28

    Aeration drying and disinfecting grain crops in bulk and pretreating seeds includes passing through a bulk of grain crops and seeds disinfecting and drying agents including an ozone and air mixture and surrounding air, subdividing the disinfecting and drying agents into a plurality of streams spaced from one another in a vertical direction, and passing the streams at different heights through levels located at corresponding heights of the bulk of grain crops and seeds transversely in a substantially horizontal direction.

  14. Role of Zinc Fertilizers in Increasing Grain Zinc Concentration and Improving Grain Yield of Rice

    OpenAIRE

    Phattarakul, Nattinee; Cakmak, Ismail; Boonchuay, Panomwan; Wongmo, Jumniun; Rerkasem, Benjavan

    2009-01-01

    Iron (Fe) toxicity is a widespread nutrient disorder and limit to grain yield in lowland rice. As it is, however, sometimes associated with deficiency of other nutrients, Fe toxicity might be also managed and alleviated by applications of concerned nutrients such as potassium (K) and zinc (Zn). However, the information on this topic available in literature is very limited, especially in the case of Zn. The objective of this study was to evaluate the effects of soil and foliar Zn applicatio...

  15. High night temperatures during grain number determination reduce wheat and barley grain yield: a field study.

    Science.gov (United States)

    García, Guillermo A; Dreccer, M Fernanda; Miralles, Daniel J; Serrago, Román A

    2015-11-01

    Warm nights are a widespread predicted feature of climate change. This study investigated the impact of high night temperatures during the critical period for grain yield determination in wheat and barley crops under field conditions, assessing the effects on development, growth and partitioning crop-level processes driving grain number per unit area (GN). Experiments combined: (i) two contrasting radiation and temperature environments: late sowing in 2011 and early sowing in 2013, (ii) two well-adapted crops with similar phenology: bread wheat and two-row malting barley and (iii) two temperature regimes: ambient and high night temperatures. The night temperature increase (ca. 3.9 °C in both crops and growing seasons) was achieved using purpose-built heating chambers placed on the crop at 19:000 hours and removed at 7:00 hours every day from the third detectable stem node to 10 days post-flowering. Across growing seasons and crops, the average minimum temperature during the critical period ranged from 11.2 to 17.2 °C. Wheat and barley grain yield were similarly reduced under warm nights (ca. 7% °C(-1) ), due to GN reductions (ca. 6% °C(-1) ) linked to a lower number of spikes per m(2) . An accelerated development under high night temperatures led to a shorter critical period duration, reducing solar radiation capture with negative consequences for biomass production, GN and therefore, grain yield. The information generated could be used as a starting point to design management and/or breeding strategies to improve crop adaptation facing climate change.

  16. Influences of Cadmium on Grain Mineral Nutrient Contents of Two Rice Genotypes Differing in Grain Cadmium Accumulation

    Institute of Scientific and Technical Information of China (English)

    CHENG Wang-da; YAO Hai-gen; ZHANG Hong-mei; TAO Xian-guo

    2009-01-01

    A pot experiment was conducted to study the effects of Cd on grain Cd, K, P, Mg, Zn, Cu, Pb, Fe and Mn accumulation in two rice genotypes (Xiushui 63 and Xiushui 217) differing in grain Cd accumulation under four Cd levels, i.e. 0, 0.5, 2.5 and 12.5 mg/kg. Rice genotype greatly affected the grain K content, but not significantly for P, Mg, Zn, Cu, Pb, Fe and Mn contents. There were remarkable effects of additional Cd on the contents of P, Mg and Zn in grains, while not significant for K, Cu, Pb, Fe and Mn contents. No significant differences were found in the interaction of genotype by additional Cd on these nine element contents. The low grain Cd accumulation genotype Xiushui 217 had significantly higher grain K, Mg, Cu and Mn contents than the high grain Cd accumulation genotype Xiushui 63, but the case was opposite for Zn, Pb and Fe contents. It also showed that Cd addition levels significantly influenced the K, P, Mg, Zn, Cu, Pb, Fe and Mn contents in rice grains. Grain K, P, Mg, Zn, Fe and Mn contents reduced with the increasing rate of Cd addition.

  17. Grain-damage hysteresis and plate tectonic states

    Science.gov (United States)

    Bercovici, David; Ricard, Yanick

    2016-04-01

    Shear localization in the lithosphere is an essential ingredient for understanding how and why plate tectonics is generated from mantle convection on terrestrial planets. The theoretical model for grain-damage and pinning in two-phase polycrystalline rocks provides a frame-work for understanding lithospheric shear weakening and plate-generation, and is consistent with laboratory and field observations of mylonites. Grain size evolves through the competition between coarsening, which drives grain-growth, and damage, which drives grain reduction. The interface between crystalline phases controls Zener pinning, which impedes grain growth. Damage to the interface enhances the Zener pinning effect, which then reduces grain-size, forcing the rheology into the grain-size-dependent diffusion creep regime. This process thus allows damage and rheological weakening to co-exist, providing a necessary positive self-weakening feedback. Moreover, because pinning inhibits grain-growth it promotes shear-zone longevity and plate-boundary inheritance. However, the suppression of interface damage at low interface curvature (wherein inter-grain mixing is inefficient and other energy sinks of deformational work are potentially more facile) causes a hysteresis effect, in which three possible equilibrium grain-sizes for a given stress coexist: (1) a stable, large-grain, weakly-deforming state, (2) a stable, small-grain, rapidly-deforming state analogous to ultramylonites, and (3) an unstable, intermediate grain-size state perhaps comparable to protomylonites. A comparison of the model to field data suggests that shear-localized zones of small-grain mylonites and ultra-mylonites exist at a lower stress than the co-existing large-grain porphyroclasts, rather than, as predicted by paleopiezometers or paleowattmeters, at a much higher stress; this interpretation of field data thus allows localization to relieve instead of accumulate stress. The model also predicts that a lithosphere that

  18. Biofortification and localization of zinc in wheat grain.

    Science.gov (United States)

    Cakmak, I; Kalayci, M; Kaya, Y; Torun, A A; Aydin, N; Wang, Y; Arisoy, Z; Erdem, H; Yazici, A; Gokmen, O; Ozturk, L; Horst, W J

    2010-08-25

    Zinc (Zn) deficiency associated with low dietary intake is a well-documented public health problem, resulting in serious health and socioeconomic problems. Field experiments were conducted with wheat to test the role of both soil and foliar application of ZnSO4 in Zn concentration of whole grain and grain fractions (e.g., bran, embryo and endosperm) in 3 locations. Foliar application of ZnSO4 was realized at different growth stages (e.g., stem elongation, boot, milk, dough stages) to study the effect of timing of foliar Zn application on grain Zn concentration. The rate of foliar Zn application at each growth stage was 4 kg of ZnSO4·7H2O ha(-1). Laser ablation (LA)-ICP-MS was used to follow the localization of Zn within grain. Soil Zn application at a rate of 50 kg of ZnSO4·7H2O ha(-1) was effective in increasing grain Zn concentration in the Zn-deficient location, but not in the locations without soil Zn deficiency. In all locations, foliar application of Zn significantly increased Zn concentration in whole grain and in each grain fraction, particularly in the case of high soil N fertilization. In Zn-deficient location, grain Zn concentration increased from 11 mg kg(-1) to 22 mg kg(-1) with foliar Zn application and to 27 mg kg(-1) with a combined application of ZnSO4 to soil and foliar. In locations without soil Zn deficiency, combination of high N application with two times foliar Zn application (e.g., at the booting and milk stages) increased grain Zn concentration, on average, from 28 mg kg(-1) to 58 mg kg(-1). Both ICP-OES and LA-ICP-MS data showed that the increase in Zn concentration of whole grain and grain fractions was pronounced when Zn was sprayed at the late growth stage (e.g., milk and dough). LA-ICP-MS data also indicated that Zn was transported into endosperm through the crease phloem. To our knowledge, this is the first study to show that the timing of foliar Zn application is of great importance in increasing grain Zn in wheat, especially in

  19. The spatial distribution of grains and crystals in rocks

    Science.gov (United States)

    Jerram, D. A.; Cheadle, Michael J.; Hunter, Robert H.; Elliott, Michael T.

    1996-09-01

    Characterisation and analysis of the spatial distribution pattern (SDP) of grains or crystals in rocks is potentially a powerful technique which can be used to constrain the processes which operate in the formation of rocks. A method to quantify the SDP of grains in thin section is presented. The distance betwen the centre of a grain and the centre of its nearest neighbour is calculated for all the grains in the sample area to produce a distribution of distances that characterises the spatial pattern of grains in the rock. This distribution is then normalised to a random distribution of points with the same population density to give a descriptive value, R. Values of R for rock samples are plotted against porosity (modal abundance of other phases in igneous and metamorphic rocks) to characterise the SDP. The SDP of randomly packed distributions of equal size spheres varies systematically with porosity, producing a line on a porosity versus R plot, termed the random sphere distribution line (RSDL). Rocks which plot above the RSDL have an ordered SDP and those that plot below, a clustered SDP. The effects of variation in grain packing order, grain sorting, compaction and random crystallisation (overgrowth) on determined R values were investigated using a combination of 3-D sphere models and 2-D texture models. The maximum possible value of R is 2.148, corresponding to a perfect section through hexagonal/cubic close packing of grains. The minimum value of R is dependent on the proportion of grains in the sample volume and may be as low as 1.2, for a sample volume with 30% grains which are clustered. Variations in size sorting can cause R to vary by approximately 0.25. Mechanical compaction of a loose framework of grains results in a higher packing order and an increase in R. Continued compaction creates a fabric in the texture and R decreases as cluster patterns are developed perpendicular to the principal stress. The overgrowth of grains in a touching framework

  20. Creep of quartz by dislocation and grain boundary processes

    Science.gov (United States)

    Fukuda, J. I.; Holyoke, C. W., III; Kronenberg, A. K.

    2015-12-01

    Wet polycrystalline quartz aggregates deformed at temperatures T of 600°-900°C and strain rates of 10-4-10-6 s-1 at a confining pressure Pc of 1.5 GPa exhibit plasticity at low T, governed by dislocation glide and limited recovery, and grain size-sensitive creep at high T, governed by diffusion and sliding at grain boundaries. Quartz aggregates were HIP-synthesized, subjecting natural milky quartz powder to T=900°C and Pc=1.5 GPa, and grain sizes (2 to 25 mm) were varied by annealing at these conditions for up to 10 days. Infrared absorption spectra exhibit a broad OH band at 3400 cm-1 due to molecular water inclusions with a calculated OH content (~4000 ppm, H/106Si) that is unchanged by deformation. Rate-stepping experiments reveal different stress-strain rate functions at different temperatures and grain sizes, which correspond to differing stress-temperature sensitivities. At 600-700°C and grain sizes of 5-10 mm, flow law parameters compare favorably with those for basal plasticity and dislocation creep of wet quartzites (effective stress exponents n of 3 to 6 and activation enthalpy H* ~150 kJ/mol). Deformed samples show undulatory extinction, limited recrystallization, and c-axis maxima parallel to the shortening direction. Similarly fine-grained samples deformed at 800°-900°C exhibit flow parameters n=1.3-2.0 and H*=135-200 kJ/mol corresponding to grain size-sensitive Newtonian creep. Deformed samples show some undulatory extinction and grain sizes change by recrystallization; however, grain boundary deformation processes are indicated by the low value of n. Our experimental results for grain size-sensitive creep can be compared with models of grain boundary diffusion and grain boundary sliding using measured rates of silicon grain boundary diffusion. While many quartz mylonites show microstructural and textural evidence for dislocation creep, results for grain size-sensitive creep may apply to very fine-grained (<10 mm) quartz mylonites.

  1. Processing of magnesium alloys with ultrafine grain structure

    Science.gov (United States)

    Figueiredo, Roberto Braga

    The relationship between processing, structure and properties is analyzed in magnesium alloys subjected to equal-channel angular pressing. Finite element modeling is used to show that the flow softening behavior associated with grain refinement might cause shear localization and billet failure in magnesium alloys processed by ECAP. It also shows that increasing the angle between the channels of the die reduces the accumulated damage in the billets and increasing the material strain rate sensitivity reduces the tendency for shear localization. Both procedures reduce the tendency for billet cracking. The mechanism of grain refinement in magnesium alloys deformed at moderate temperatures differs from that observed in other metals such as copper and aluminum. Fine grains nucleate along pre-existing grain boundaries in a necklace pattern in coarse-grained magnesium while homogeneous nucleation of fine grains is observed in fine-grained. A bimodal grain size distribution is observed after processing alloys from an initial coarse structure and a homogeneous distribution of ultrafine grains is the outcome of a starting fine one. Experiments and simulations are used to analyze the evolution of texture. It is shown that different components are formed depending on the activity ratio of non-basal slip and processing route. The measured pole figures exhibit features characteristic of high activity of non-basal slip. It is also shown that the development of some texture components and their orientation depends on the initial texture and the die angle which provide the basis for future texture engineering. Excellent superplastic properties, including a record elongation for a magnesium alloy, were observed after ECAP. Systematic research showed that the structure characteristics prior and after ECAP play significant role on these properties. Grain growth during superplastic deformation causes a strain hardening effect. The experimental results showed good agreement with the

  2. Manipulating plant geometry to improve microclimate, grain yield, and harvest index in grain sorghum

    Science.gov (United States)

    Stewart, Bob A.; Xue, Qingwu; Chen, Yuanquan

    2017-01-01

    Cultivar selection, planting geometry, and plant population are the key factors determining grain sorghum yields in water deficit areas. The objective of this study was to investigate whether clump geometry (three plants clustered) improves microclimate within crop canopy when plants are grown under varying water levels. In a 2-yr sorghum (Sorghum bicolor L. Moench) greenhouse study, plants were grown at two geometries (clump and conventional evenly spaced planting, ESP), two water levels (high and low, representing well-watered and water-limited condition, respectively), and three soil surface treatments (lid covered, straw-mulched, and bare). Air temperature and relative humidity (RH) within the plant canopy were measured every five minutes at different growth stages. Mean vapor pressure deficits (VPDs) within the clumps were consistently lower than those for ESPs, indicating that clumps improved the microclimate. Clumps had significantly higher harvest index (HI) compared to ESPs (0.48 vs. 0.43), which was largely due to clumps having an average of 0.4 tillers per plant compared to 1.2 tillers per plant for ESPs. Grain yield in the current study was similar between clumps and ESPs. However, our results suggest that improved microclimate was likely a reason for clumps producing significantly higher grain yields compared to ESPs in previous studies. PMID:28264051

  3. Laboratory Studies Of Circumstellar Carbonaceous Grain Formation

    Science.gov (United States)

    Contreras, Cesar; Sciamma-O'Brien, Ella; Salama, Farid

    2014-06-01

    The study of the formation processes of dust is essential to understand the budget of extraterrestrial organic molecules. Although dust with all its components plays an important role in the evolution of interstellar (IS) chemistry and in the formation of organic molecules, little is known on the formation processes of carbonaceous dust. We report the progress that was recently achieved in this domain using NASA Ames’ COSmIC facility (Contreras & Salama 2013, ApJS, 208, 6). PAHs are important chemical building blocks of IS dust. They are detected in IDPs and in meteoritic samples. Additionally, observational, laboratory, and theoretical studies have shown that PAHs are an important, ubiquitous component of the ISM. The formation of PAHs from smaller molecules has not been extensively studied. Therefore, we have performed laboratory experiments to study the dynamic processes of carbon grain formation, starting from the smallest hydrocarbon molecules into the formation of larger PAH and further into nanograins. Studies of IS dust analogs formed from a variety of PAH and hydrocarbon precursors as well as species that include the atoms O, N, and S, have recently been performed in our laboratory using the COSmIC facility to provide conditions that simulate IS and circumstellar environments. The species formed in the COSmiC chamber through a pulsed discharge nozzle plasma source are detected and characterized with a cavity ringdown spectrometer coupled to a time-of-flight mass spectrometer, thus providing both spectroscopic and ion mass information in-situ. Analysis of solid soot particles was also conducted using scanning electron microscopy at the UCSC/NASA Ames’ MACS facility. The SEM analysis of the deposition of soot from methane and acetylene precursors seeded in argon plasmas provide examples on the types of nanoparticles and micrograins that are produced in these gas mixtures under our experimental conditions. From these measurements, we derive information on

  4. Bioactivities and antiradical properties of millet grains and hulls.

    Science.gov (United States)

    Chandrasekara, Anoma; Shahidi, Fereidoon

    2011-09-14

    Antioxidant activities of phenolic extracts of kodo and pearl millet whole grains, dehulled grains, and hulls were examined by monitoring inhibition of radical-induced DNA scission, human low-density lipoprotein (LDL) cholesterol, and phospholipid liposome oxidation. Total phenolic content (TPC), hydroxyl and peroxyl radical inhibition, and antiproliferative activities against HT-29 cells were also determined. Major hydroxycinnamic acids in dehulled grains and hulls were identified and quantified using HPLC. Phenolic extract of kodo millet exhibited higher inhibition activities against oxidation of LDL cholesterol and liposome than that of pearl millet. All phenolic extracts exhibited a dose-dependent inhibition of DNA scission. The TPC of hulls of kodo and pearl millets were 3 times higher than those of their corresponding whole grains. At the end of 96 h of incubation, kodo millet extracts inhibited cell proliferation in the range of 75-100%. Antioxidant activities of phenolic extracts were in the order hull > whole grain > dehulled grain. Dehulling reduced the antioxidant potential of whole millet grains. Ferulic and p-coumaric acids were the major hydroxycinnamic acids, and their contents ranged from 17.8 to 1685 μg/g defatted meal and from 3.5 to 680 μg/g defatted meal, respectively. Dehulled grains, as well as the hull fraction, may serve as potential sources of nutraceutical and functional food ingredients in health promotion.

  5. 7 CFR 457.113 - Coarse grains crop insurance provisions.

    Science.gov (United States)

    2010-01-01

    ... total production in bushels (tons for corn silage) (see subsection 11(d)) to count from all insurable... production to count for corn will be in bushels for grain and in tons for silage as follows: (1) For... coarse grain production (excluding corn insured or harvested as silage) may be adjusted for...

  6. Deformation of fine-grained synthetic peridotite under wet conditions

    NARCIS (Netherlands)

    McDonnell, R.D.

    1997-01-01

    Fine-grained hydrated peridotite mylonites have been proposed to play an important role in controlling the strength of the continental lithosphere during rifting. For this reason, the deformation behaviour of wet fine-grained forsterite and forsterite-enstatite materials and the underlying deformati

  7. Observational tests for grain chemistry: posterior isotopic labelling

    NARCIS (Netherlands)

    Charnley, S.B.; Ehrenfreund, P.; Millar, T.J.; Boogert, A.C.A.; Markwick, A.J.; Butner, H.M.; Ruiterkamp, R.; Rodgers, S.D.

    2004-01-01

    We propose a series of detailed observations that should allow current ideas concerning the important catalytic pathways to interstellar molecules on interstellar dust grains to be tested. The atoms and molecules that accrete on cold grains and take part in surface reactions will be selectively frac

  8. Field measurements for food grain packing factors in US

    Science.gov (United States)

    Grain is commonly stored in tall bins, often exceeding 30 m deep, in commercial storage facilities. Grain can support the large overbearing pressure without crushing; however, it yields somewhat to compaction due to the overbearing pressure leading to an increase in bulk density and change in volume...

  9. D2 dining center wins whole grains challenge

    OpenAIRE

    Dawson, Brandi

    2007-01-01

    The Whole Grains Council and Oldways food issues advocacy group challenged restaurants and foodservice operations across the country to step up to the plate and offer more whole grain options this summer. Virginia Tech's Dining Services did just that and swept the competition, winning the college/university category, as well as the grand prize, beating out entries from nine other categories.

  10. Accommodation of Plastic Deformation by Ultrasound-Induced Grain Rotation

    NARCIS (Netherlands)

    Dutta, R.K.; Petrov, R.H.; Hermans, M.J.M.; Richardson, I.M.

    2015-01-01

    Electron backscatter diffraction was used to investigate the softening effect in low-carbon steel [Fe-0.051C-0.002Si-0.224Mn-0.045Al (wt pct)] during tensile deformation with in situ ultrasonic treatment. A bimodal grain size distribution is observed with relatively small equiaxed grains with an ave

  11. Dynamic recrystallization and grain growth in olivine rocks

    NARCIS (Netherlands)

    Kellermann Slotemaker, A.

    2006-01-01

    A mechanism based description of the rheology of olivine is essential for modeling of upper mantle geodynamics. Previously, mantle flow has been investigated using flow laws for grain size insensitive (GSI) dislocation creep and/or grain size sensitive (GSS) diffusion creep of olivine. Generally, fl

  12. 76 FR 59186 - Renewal of National Grain Car Council

    Science.gov (United States)

    2011-09-23

    ... Board intends to renew the charter of the National Grain Car Council (NGCC). ADDRESSES: A copy of the charter is available at the Library of the Surface Transportation Board, 395 E Street, SW., Washington, DC... Surface Transportation Board Renewal of National Grain Car Council AGENCY: Surface Transportation...

  13. 78 FR 58383 - Renewal of National Grain Car Council

    Science.gov (United States)

    2013-09-23

    ... Board intends to renew the charter of the National Grain Car Council (NGCC). ADDRESSES: A copy of the charter is available at the Library of the Surface Transportation Board, 395 E Street SW., Washington, DC... Surface Transportation Board Renewal of National Grain Car Council AGENCY: Surface Transportation...

  14. Ecology and IPM of Insects at Grain Elevators

    Science.gov (United States)

    Cost-effectiveness of insect pest management depends upon its integration with other elevator operations. Successful integration may require consideration of insect ecology. Field infestation has not been observed for grain received at elevators. Grain may be infested during harvest by residual inse...

  15. Complicated hollow turbine blades and surface grain refinement process

    Directory of Open Access Journals (Sweden)

    Peng Zhijiang

    2010-05-01

    Full Text Available The control of grain size in superalloys is critical in the manufacture of gas turbine blades. The aim of the present research is to provide the technology for producing complicated hollow turbine blades with fine surface grains and better comprehensive mechanical properties. By melt superheating treatment and coating the internal surfaces of shell mould using a cobalt aluminate-bearing coating material, the influence of cobalt aluminate as inoculant on the surface grain sizes of turbine blade was studied with addition of cobalt aluminate: 0, 35%, 45% – 65% and 100% respectively. At the same time, the effects of cooling circumstances of the blades on surface grain sizes were also experimented under the same addition of cobalt aluminate. The results showed that the melt superheating treatment plays a significant role in the grain size and carbide morphology; and fine surface grains were obtained when the internal surfaces of shell mould were coated using cobalt aluminate coatings. When the addition of cobalt aluminate in coating is between 45% - 65%, and the melt is poured into preheated shell moulds with fine silica sand as backing sand, the blades satisfied the surface grain size requirement is over 90%. In addition, comparisons of the surface grain size and the mechanical properties were also conducted between home-made and foreign-made blades.

  16. Computing wheat nitrogen requirements from grain yield and protein maps

    Science.gov (United States)

    Optical protein sensors and mass-flow yield monitors provide the opportunity to continuously measure grain quality and quantity during harvesting. This chapter illustrates how yield monitor and grain protein measurements may provide useful postharvest information for evaluating water or nitrogen (N)...

  17. Exploring the Use of Whole Grain Pasta in School Lunches

    Science.gov (United States)

    Rosen, Renee A.; Hauge, Denise A.; Arndt, Elizabeth A.; Veal, Mike; Marquart, Len

    2011-01-01

    Pasta is a popular grain food served as an entree or side dish in both home and away-from-home settings. In schools, pasta is served less frequently than other entrees. Pasta, especially whole-grain pasta, offers an opportunity to incorporate less expensive, nutritious, and versatile dishes into school meals. A need exists to develop whole-grain…

  18. Enhancing the health-beneficial qualities of whole grain rice

    Science.gov (United States)

    Various pre- and post-harvest approaches (i.e. pre-germination of whole grains and reduced milling degree) to enhancing the health beneficial compounds of whole grain and milled rice have been reported. A discussion of the results from our pre-harvest efforts is as follows. The majority of rice cons...

  19. Expression of lipoxygenase isoenzymes in developing barley grains

    NARCIS (Netherlands)

    Schmitt, N.F.; Mechelen, J.R. van

    1997-01-01

    Expression of lipoxygenase was studied in whole developing barley grains from 5 days after flowering (DAF) to full maturity. Lipoxygenase showed two distinct peaks of activity. The first peak of activity occurred in the early stages of grain development from 5 until 20 DAF, whereas the second peak o

  20. Size modification of recent pollen grains under different treatments

    NARCIS (Netherlands)

    Reitsma, Tj.

    1969-01-01

    The effect of various chemicals on the size of recent pollen grains of Corylus avellana L. and Quercus robur L. was studied. The size of acetolysed grains was affected by the treatment prior to acetolysis and moreover by the duration of acetolysis. Preparation methods, which produce comparable sizes

  1. Cavitation-aided grain refinement in aluminium alloys

    NARCIS (Netherlands)

    Atamanenko, T.V.

    2010-01-01

    This thesis deals with grain refinement under the influence of ultrasonic-driven cavitation in aluminium casting processes. Three major goals of this research were: (1) to identify the mechanism of the cavitation-aided grain refinement at different stages of solidification; (2) to reveal the conditi

  2. Revisiting Acceleration of Charged Grains in Magnetohydrodynamic Turbulence

    CERN Document Server

    Hoang, Thiem; Schlickeiser, R

    2011-01-01

    We study the acceleration of charged grains by magnetohydrodynamics (MHD) turbulence in the interstellar medium (ISM). We begin with revisiting gyroresonance acceleration by taking into account fluctuations of the grain guiding center along a uniform magnetic field (i.e. non-linear theory, NLT). We calculate grain velocity due to gyroresonance acceleration by fast modes using the NLT for different phases of the ISM, and compare with results obtained using quasi-linear theory (QLT). We find that the fluctuations of the grain guiding center reduce the grain velocity by less than 15 percent, but large grains are still accelerated to super-Alfvenic speed. For such super-Alfvenic grains, we investigate the effect of transit time damping (TTD) by fast modes. We find that due to the broadening of resonance condition in the NLT, the TTD acceleration is not only important for the cosine pitch angle $\\mu>V_{A}/v$, but also for $\\mugrain velocity and $V_{\\A}$ is Alfven speed. We show that t...

  3. Does Whole Grain Consumption Alter Gut Microbiota and Satiety?

    Directory of Open Access Journals (Sweden)

    Danielle N. Cooper

    2015-05-01

    Full Text Available This review summarizes recent studies examining whole grain consumption and its effect on gut microbiota and satiety in healthy humans. Studies comparing whole grains to their refined grain counterparts were considered, as were studies comparing different grain types. Possible mechanisms linking microbial metabolism and satiety are described. Clinical trials show that whole grain wheat, maize, and barley alter the human gut microbiota, but these findings are based on a few studies that do not include satiety components, so no functional claims between microbiota and satiety can be made. Ten satiety trials were evaluated and provide evidence that whole oats, barley, and rye can increase satiety, whereas the evidence for whole wheat and maize is not compelling. There are many gaps in the literature; no one clinical trial has examined the effects of whole grains on satiety and gut microbiota together. Once understanding the impact of whole grains on satiety and microbiota is more developed, then particular grains might be used for better appetite control. With this information at hand, healthcare professionals could make individual dietary recommendations that promote satiety and contribute to weight control.

  4. Single Grain Si TFTs for RF and 3D ICs

    NARCIS (Netherlands)

    Ishihara, R.; Baiano, A.; Chen, T.; Derakhshandeh, J.; Tajari Mofrad, M.R.; Danesh, M.; Saputra, N.; Long, J.; Beenakker, C.I.M.

    2009-01-01

    Single-grain Si TFTs have been fabricated using accurate 2D location control of large Si grain with the μ-Czochralski process. TFTs fabricated inside the crystalline islands of 6 μm show a mobility (600cm2/Vs) as high as that of the SOI counterpart, despite of the low-temperature (<350oC) process. B

  5. A Madurella mycetomatis Grain Model in Galleria mellonella Larvae.

    Directory of Open Access Journals (Sweden)

    Wendy Kloezen

    Full Text Available Eumycetoma is a chronic granulomatous subcutaneous infectious disease, endemic in tropical and subtropical regions and most commonly caused by the fungus Madurella mycetomatis. Interestingly, although grain formation is key in mycetoma, its formation process and its susceptibility towards antifungal agents are not well understood. This is because grain formation cannot be induced in vitro; a mammalian host is necessary to induce its formation. Until now, invertebrate hosts were never used to study grain formation in M. mycetomatis. In this study we determined if larvae of the greater wax moth Galleria mellonella could be used to induce grain formation when infected with M. mycetomatis. Three different M. mycetomatis strains were selected and three different inocula for each strain were used to infect G. mellonella larvae, ranging from 0.04 mg/larvae to 4 mg/larvae. Larvae were monitored for 10 days. It appeared that most larvae survived the lowest inoculum, but at the highest inoculum all larvae died within the 10 day observation period. At all inocula tested, grains were formed within 4 hours after infection. The grains produced in the larvae resembled those formed in human and in mammalian hosts. In conclusion, the M. mycetomatis grain model in G. mellonella larvae described here could serve as a useful model to study the grain formation and therapeutic responses towards antifungal agents in the future.

  6. Grain Growth in Samples of Aluminum Containing Alumina Particles

    DEFF Research Database (Denmark)

    Tweed, C. J.; Hansen, Niels; Ralph, B.

    1983-01-01

    A study of the two-dimensional and three-dimensional grain size distributions before and after grain growth treatments has been made in samples having a range of oxide contents. In order to collect statistically useful amounts of data, an automatic image analyzer was used and the resulting data w...

  7. Computer-aided analysis of grain growth in metals

    DEFF Research Database (Denmark)

    Klimanek, P.; May, C.; Richter, H.

    1993-01-01

    Isothermal grain growth in aluminium, copper and alpha-iron was investigated experimentally at elevated temperatures and quantitatively interpreted by computer simulation on the base of a statistical model described in [4,5,6]. As it is demonstrated for the grain growth kinetics, the experimental...

  8. New 3DXRD results on recrystallization and grain growth

    DEFF Research Database (Denmark)

    Juul Jensen, Dorte; West, Stine; Poulsen, Stefan Othmar;

    2012-01-01

    New in-situ 3DXRD results obtained since the last Rex&GG conference are presented and discussed. This includes: Documentation of the formation of nuclei with new orientations, determination of apparent activation energies for individual bulk grains during recrystallization and evolution in the 3D...... microstructure during grain growth...

  9. A numerical model of stress driven grain boundary diffusion

    Science.gov (United States)

    Sethian, J. A.; Wilkening, Jon

    2004-01-01

    The stress driven grain boundary diffusion problem is a continuum model of mass transport phenomena in microelectronic circuits due to high current densities (electromigration) and gradients in normal stress along grain boundaries. The model involves coupling many different equations and phenomena, and difficulties such as non-locality, stiffness, complex geometry, and singularities in the stress tensor near corners and junctions make the problem difficult to analyze rigorously and simulate numerically. We present a new numerical approach to this problem using techniques from semigroup theory to represent the solution. The generator of this semigroup is the composition of a type of Dirichlet to Neumann map on the grain boundary network with the Laplace operator on the network. To compute the former, we solve the equations of linear elasticity several times, once for each basis function on the grain boundary. We resolve singularities in the stress field near corners and junctions by adjoining special singular basis functions to both finite element spaces (2d for elasticity, 1d for grain boundary functions). We develop data structures to handle jump discontinuities in displacement across grain boundaries, singularities in the stress field, complicated boundary conditions at junctions and interfaces, and the lack of a natural ordering for the nodes on a branching grain boundary network. The method is used to study grain boundary diffusion for several geometries.

  10. Genetic Potential of Winter Wheat Grain Quality in Central Asia

    Science.gov (United States)

    Abugaliyeva, Aigul I.; Morgounov, Alexey I.

    2016-01-01

    The grain quality of winter wheat varies significantly by cultivars and growing region, not previously differentiated by end-use (baking, confectionery, etc.) in the national breeding programs. In these conditions it is advisable to determine the genetic potential and analyze the actual grain quality. Determining the genetic potential requires the…

  11. The influence of grain size, grain color, and suspended-sediment concentration on light attenuation: why fine-grained terrestrial sediment is bad for coral reef ecosystems

    Science.gov (United States)

    Storlazzi, Curt; Norris, Benjamin; Rosenberger, Kurt

    2015-01-01

    Sediment has been shown to be a major stressor to coral reefs globally. Although many researchers have tested the impact of sedimentation on coral reef ecosystems in both the laboratory and the field and some have measured the impact of suspended sediment on the photosynthetic response of corals, there has yet to be a detailed investigation on how properties of the sediment itself can affect light availability for photosynthesis. We show that finer-grained and darker-colored sediment at higher suspended-sediment concentrations attenuates photosynthetically active radiation (PAR) significantly more than coarser, lighter-colored sediment at lower concentrations and provide PAR attenuation coefficients for various grain sizes, colors, and suspended-sediment concentrations that are needed for biophysical modeling. Because finer-grained sediment particles settle more slowly and are more susceptible to resuspension, they remain in the water column longer, thus causing greater net impact by reducing light essential for photosynthesis over a greater duration. This indicates that coral reef monitoring studies investigating sediment impacts should concentrate on measuring fine-grained lateritic and volcanic soils, as opposed to coarser-grained siliceous and carbonate sediment. Similarly, coastal restoration efforts and engineering solutions addressing long-term coral reef ecosystem health should focus on preferentially retaining those fine-grained soils rather than coarse silt and sand particles.

  12. Science at the interface : grain boundaries in nanocrystalline metals.

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Mark Andrew; Follstaedt, David Martin; Knapp, James Arthur; Brewer, Luke N.; Holm, Elizabeth Ann; Foiles, Stephen Martin; Hattar, Khalid M.; Clark, Blythe B.; Olmsted, David L.; Medlin, Douglas L.

    2009-09-01

    Interfaces are a critical determinant of the full range of materials properties, especially at the nanoscale. Computational and experimental methods developed a comprehensive understanding of nanograin evolution based on a fundamental understanding of internal interfaces in nanocrystalline nickel. It has recently been shown that nanocrystals with a bi-modal grain-size distribution possess a unique combination of high-strength, ductility and wear-resistance. We performed a combined experimental and theoretical investigation of the structure and motion of internal interfaces in nanograined metal and the resulting grain evolution. The properties of grain boundaries are computed for an unprecedented range of boundaries. The presence of roughening transitions in grain boundaries is explored and related to dramatic changes in boundary mobility. Experimental observations show that abnormal grain growth in nanograined materials is unlike conventional scale material in both the level of defects and the formation of unfavored phases. Molecular dynamics simulations address the origins of some of these phenomena.

  13. Buchert coarse-graining and the classical energy conditions

    CERN Document Server

    Visser, Matt

    2015-01-01

    So-called "Buchert averaging" is actually a coarse-graining procedure, where fine detail is "smeared out" due to limited spatio-temporal resolution. For technical reasons, (to be explained herein), "averaging" is not really an appropriate term, and I shall consistently describe the process as a "coarse-graining". Because Einstein gravity is nonlinear the coarse-grained Einstein tensor is typically not equal to the Einstein tensor of the coarse-grained spacetime geometry. The discrepancy can be viewed as an "effective" stress-energy, and this "effective" stress-energy often violates the classical energy conditions. To keep otherwise messy technical issues firmly under control, I shall work with conformal-FLRW (CFLRW) cosmologies. These CFLRW-based models are particularly tractable, and are also particularly attractive observationally: the CMB is not distorted. In this CFLRW context one can prove some rigorous theorems regarding the interplay between Buchert coarse-graining, tracelessness of the effective stres...

  14. Diffusion behaviors of helium atoms at two Pd grain boundaries

    Institute of Scientific and Technical Information of China (English)

    XIA Ji-xing; HU Wang-yu; YANG Jian-yu; AO Bing-yun

    2006-01-01

    The diffusion behaviors of helium atoms at two symmetric grain boundaries (Σ5{210} and Σ3 {112}) of Pd were investigated using molecular dynamics simulations through an analytical embedded-atom method(MAEAM) model. The simulations demonstrate that the interstitial helium atoms are easily trapped at the grain boundaries and precipitated into clusters. Due to the closed-shell electronic configurations of both helium and palladium,Pd grain boundaries yield strong capability of retaining helium atoms. By calculating the mean square displacements(MSD) of an interstitial helium atom at the grain boundaries,the diffusion coefficients were determined,and the linear fits to Arrhenius relation. The diffusion activation energies of interstitial helium atom at these two Pd grain boundaries were also evaluated.

  15. Improving Rollback-Recovery Efficiency by Tuning Pessimism Grain

    Institute of Scientific and Technical Information of China (English)

    YANG Jinmin; ZHANG Dafang; LI Kin Fun; CHENG Jing

    2007-01-01

    Wide-area systems are becoming a popular infrastructure for long-running applications. Rollbackrecovery, as a common technology for fault tolerance and load balance, must meet the challenges of scalability and inherent variability in such applications. Most of the rollback-recovery protocols, however, are poor in scalability. Although pessimistic message logging protocols have no such problem, their fault-free overhead sometimes is prohibitive. Aiming at good scalability and acceptable overhead, this paper introduces the concept of pessimism grain and presents a coarse-grained pessimistic message-logging scheme. The paper also evaluates the impact of pessimism grain on the performance of the recovery scheme. Experimental results show that pessimism grain is one of the key configuration parameters to reach a desired performance level. In practice, the proper pessimism grain should be selected based on the characteristics of the applications.

  16. Effects of grain boundaries on electrical property of copper wires

    Institute of Scientific and Technical Information of China (English)

    严文; 陈建; 范新会

    2003-01-01

    By means of annealing at different temperatures, the copper wires with various numbers of grain boundaries were achieved. And the resistivity of copper wires was measured. The results show that with increasing the number of grain boundaries, the resistivity of copper wires increases, the relationship between the number of grain boundaries and the resistivity of cooper wires can be expressed as y=1.86×10-8e-0.90/x. Unlike dislocation and lattice vacant sites, the curve of the grain boundary vs the resistivity is not linear. Grain boundary controls the general trend of the curve, but the type and the quantity of impurity controls the details of the curve.

  17. Porous and Fluffy Grains in the Regions of Anomalous Extinction

    Indian Academy of Sciences (India)

    D. B. Vaidya; B. G. Anandarao; J. N. Desai; R. Gupta

    2000-06-01

    It has long been established that the ratio of total to selective extinction is anomalously large (≥ 5) in certain regions of the interstellar medium. In these regions of anomalous extinction the dust grains are likely to be irregular in shape and fluffy in structure. Using discrete dipole approximation (DDA) we calculate the extinction for porous and fluffy grains. We apply DDA first to solid spheroidal particles assumed to be made of a certain (large) number of dipoles. Then we systematically reduce the number of dipoles to model the porous grains. The aggregates of these particles are suggested to form the fluffy grains. We study the extinction for these particles as a function of grain size, porosity and wavelength. We apply these calculations to interpret the observed extinction data in the regions of star formation (e.g. the Orion complex).

  18. Whole grain foods and health - A Scandinavian perspective

    DEFF Research Database (Denmark)

    Frølich, Wenche; Aman, Per; Tetens, Inge

    2013-01-01

    and health effects of the final whole grain products. Future research should consider the specific properties of each cereal and its processing methods to further identify the uniqueness and health potentials of whole grain products. This would enable the authorities to provide more specific food......The food-based dietary guidelines in the Scandinavian countries that recommend an intake of minimum 75 g whole grain per 10 MJ (2,388 kcal) per day are mainly derived from prospective cohort studies where quantitative but little qualitative details are available on whole grain products....... The objective of the current paper is to clarify possible differences in nutritional and health effects of the types of whole grain grown and consumed in the Scandinavian countries. A further objective is to substantiate how processing may influence the nutritional value and potential health effects...

  19. Atomistic aspects of crack propagation along high angle grain boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, D. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Materials Science and Engineering

    1997-12-31

    The author presents atomistic simulations of the crack tip configuration near a high angle {Sigma} = 5 [001](210) symmetrical tilt grain boundary in NiAl. The simulations were carried out using molecular statics and embedded atom (EAM) potentials. The cracks are stabilized near a Griffith condition involving the cohesive energy of the grain boundary. The atomistic configurations of the tip region are different in the presence of the high angle grain boundary than in the bulk. Three different configurations of the grain boundary were studied corresponding to different local compositions. It was found that in ordered NiAl, cracks along symmetrical tilt boundaries show a more brittle behavior for Al rich boundaries than for Ni-rich boundaries. Lattice trapping effects in grain boundary fracture were found to be more significant than in the bulk.

  20. Grain boundary structure in Ni{sub 3}Al

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, D. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Materials Engineering

    1996-08-01

    The multiplicity of possible grain boundary structures was studied for the ordered compound Ni{sub 3}Al. Two symmetrical tilt boundaries were chosen for the detailed study corresponding to {Sigma}=3 left angle 110 right angle {l_brace}112{r_brace} and {Sigma}=9 left angle 110 right angle {l_brace}114{r_brace}. These boundaries were investigated considering possible variations of the local chemical composition and environment using atomistic computer simulation with EAM interatomic potentials. Many different grain boundary structures were found having very similar energies for the same orientation of the two crystals and the grain boundary plane. Possible transformations among these structures may result from the interaction of the boundaries with dislocations or antiphase boundaries. The role of the multiplicity of structures and these transformations in the grain boundary mechanical properties is discussed. In this paper, we explore the role that different possible grain boundary structures play in intermetallic alloys. (orig.)

  1. Cereal Grains: Their Impacts on Health and Food Safety

    Institute of Scientific and Technical Information of China (English)

    P Rayas-Duarte; J Uriyapongson

    2006-01-01

    Cereal grains can contribute to maintain health and prevent chronic diseases by supplying biologically active components. The exact mechanism of action of these components is not completely understood, but extensive evidence suggests the antioxidants that are present in the grains are the likely source of benefits. These activities or properties might protect against coronary heart disease and diabetes. The relationships of complex carbohydrates, whole grain products and the prevention of diseases, including type2 diabetes mellitus and coronary heart disease continue to challenge the scientific community. Though cereal grains contribute to a healthy diet there are some people that can not tolerate the proteins present in the grain. This can lead to food allergies and when severe can be diagnosed as celiac disease.

  2. Pure iron grains are rare in the universe

    Science.gov (United States)

    Kimura, Yuki; Tanaka, Kyoko K.; Nozawa, Takaya; Takeuchi, Shinsuke; Inatomi, Yuko

    2017-01-01

    The abundant forms in which the major elements in the universe exist have been determined from numerous astronomical observations and meteoritic analyses. Iron (Fe) is an exception, in that only depletion of gaseous Fe has been detected in the interstellar medium, suggesting that Fe is condensed into a solid, possibly the astronomically invisible metal. To determine the primary form of Fe, we replicated the formation of Fe grains in gaseous ejecta of evolved stars by means of microgravity experiments. We found that the sticking probability for the formation of Fe grains is extremely small; only a few atoms will stick per hundred thousand collisions so that homogeneous nucleation of metallic Fe grains is highly ineffective, even in the Fe-rich ejecta of type Ia supernovae. This implies that most Fe is locked up as grains of Fe compounds or as impurities accreted onto other grains in the interstellar medium. PMID:28116359

  3. Granular gases of rod-shaped grains in microgravity.

    Science.gov (United States)

    Harth, K; Kornek, U; Trittel, T; Strachauer, U; Höme, S; Will, K; Stannarius, R

    2013-04-05

    Granular gases are convenient model systems to investigate the statistical physics of nonequilibrium systems. In the literature, one finds numerous theoretical predictions, but only few experiments. We study a weakly excited dilute gas of rods, confined in a cuboid container in microgravity during a suborbital rocket flight. With respect to a gas of spherical grains at comparable filling fraction, the mean free path is considerably reduced. This guarantees a dominance of grain-grain collisions over grain-wall collisions. No clustering was observed, unlike in similar experiments with spherical grains. Rod positions and orientations were determined and tracked. Translational and rotational velocity distributions are non-Gaussian. Equipartition of kinetic energy between translations and rotations is violated.

  4. Pure iron grains are rare in the universe.

    Science.gov (United States)

    Kimura, Yuki; Tanaka, Kyoko K; Nozawa, Takaya; Takeuchi, Shinsuke; Inatomi, Yuko

    2017-01-01

    The abundant forms in which the major elements in the universe exist have been determined from numerous astronomical observations and meteoritic analyses. Iron (Fe) is an exception, in that only depletion of gaseous Fe has been detected in the interstellar medium, suggesting that Fe is condensed into a solid, possibly the astronomically invisible metal. To determine the primary form of Fe, we replicated the formation of Fe grains in gaseous ejecta of evolved stars by means of microgravity experiments. We found that the sticking probability for the formation of Fe grains is extremely small; only a few atoms will stick per hundred thousand collisions so that homogeneous nucleation of metallic Fe grains is highly ineffective, even in the Fe-rich ejecta of type Ia supernovae. This implies that most Fe is locked up as grains of Fe compounds or as impurities accreted onto other grains in the interstellar medium.

  5. Pipe and grain boundary diffusion of He in UO2

    Science.gov (United States)

    Galvin, C. O. T.; Cooper, M. W. D.; Fossati, P. C. M.; Stanek, C. R.; Grimes, R. W.; Andersson, D. A.

    2016-10-01

    Molecular dynamics simulations have been conducted to study the effects of dislocations and grain boundaries on He diffusion in \\text{U}{{\\text{O}}2} . Calculations were carried out for the {1 0 0}, {1 1 0} and {1 1 1} edge dislocations, the screw dislocation and Σ5, Σ13, Σ19 and Σ25 tilt grain boundaries. He diffusivity as a function of distance from the dislocation core and grain boundaries was investigated for the temperature range 2300-3000 K. An enhancement in diffusivity was predicted within 20 Å of the dislocations or grain boundaries. Further investigation showed that He diffusion in the edge dislocations follows anisotropic behaviour along the dislocation core, suggesting that pipe diffusion occurs. An Arrhenius plot of He diffusivity against the inverse of temperature was also presented and the activation energy calculated for each structure, as a function of distance from the dislocation or grain boundary.

  6. Grain Alignment by Radiative Torques in Special Conditions and Implications

    CERN Document Server

    Hoang, Thiem

    2014-01-01

    Grain alignment by radiative torques (RATs) has been extensively studied for various environment conditions, including interstellar medium, dense molecular clouds, and accretion disks, thanks to significant progress in observational, theoretical and numerical studies. In this paper, we explore the alignment by RATs and provide quantitative predictions of dust polarization for a set of astrophysical environments that can be tested observationally. We first consider the alignment of grains in the local interstellar medium and compare predictions for linear polarization by aligned grains with recent observational data for nearby stars. We then revisit the problem of grain alignment in accretions disks by taking into account the dependence of RAT alignment efficiency on the anisotropic direction of radiation fields relative to magnetic fields. Moreover, we study the grain alignment in interplanetary medium, including diffuse Zodiacal cloud and cometary comae, and calculate the degree of circular polarization (CP)...

  7. Acceleration of Small Dust Grains due to Charge Fluctuations

    CERN Document Server

    Hoang, Thiem

    2011-01-01

    We consider the acceleration of very small dust grains including Polycyclic Aromatic Hydrocarbons (PAHs) arising from the electrostatic interactions of dust grains that have charge fluctuates in time due to charging events. We simulate the charge fluctuations of very small grains due to their sticking collisions with electrons and ions in plasma and the emission of photoelectrons by UV photons using Monte Carlo method. We identify the acceleration induced by the charge fluctuations as the dominant acceleration mechanism of very small grains in the diffuse interstellar medium (ISM). We show that this acceleration mechanism is more efficient for environments with low ionization, where the charge fluctuations are slow but have a large amplitude. We also discuss the implications of the present mechanism for grain coagulation and shattering in the diffuse ISM, molecular clouds and protoplanetary disks.

  8. High Standard Capital Farmland Construction Based on Grain Security

    Institute of Scientific and Technical Information of China (English)

    Zhi ZHANG; Zhongxiang YU

    2016-01-01

    In the context that global grain security is still in very severe situation,the grain security situation in China is not optimistic as well. The " Red Line of Farmland Area" cannot completely solve the grain security problems in China. We still need to seek new breakthroughs in the quality and yield of farmland. The construction of high standard capital farmland is the important premise to guarantee national grain security. On this basis,this paper has summarized the difficulties we are facing in the construction of high standard capital farmland,and has proposed the methods and measures to construct high standard capital farmland and lay a solid foundation for grain security in China.

  9. Grain boundaries in polycrystalline Si solar cells Impurities and passivation

    Science.gov (United States)

    Kazmerski, L. L.

    The interrelationships among the chemistry and composition of the intergrain regions, the electro-optical properties of the grain boundaries, and the resulting photovoltaic performance of polycrystalline Si solar cells are examined. Specifically, two impurity-related mechanisms are reported. The first is that of the segregation of oxygen to the grain boundaries during thermal processing of the material/devices. Direct evidence is presented that correlates this oxygen localization to the electrical activation of the grain boundaries. The second is the passivation of the grain boundaries by incorporation of hydrogen in these regions. The localization of hydrogen at the intergrain defects is shown by surface analysis methods, and the effects on the electrical characteristics of the grain boundary and the solar cells are reported.

  10. STRESS DISTRIBUTION NEAR GRAIN BOUNDARY IN ANISOTROPIC BICRYSTALS AND TRICRYSTALS

    Institute of Scientific and Technical Information of China (English)

    万建松; 岳珠峰

    2004-01-01

    The rate dependent crystallographic finite element program was implemented in ABAQUS as a UMAT for the analysis of the stress distributions near grain boundary in anisotropic bicrystals and tricrystals, taking the different crystallographic orientations into consideration. The numerical results of bicrystals model with the different crystallographic orientations shows that there is a high stress gradient near the grain boundaries. The characteristics of stress structures are dependent on the crystallographic orientations of the two grains. The existing of triple junctions in the tricrystals may result in the stress concentrations, or may not, depending on the crystallographic orientations of the three grains. The conclusion shows that grain boundary with different crystallographic orientations can have different deformation, damage, and failure behaviors. So it is only on the detail study of the stress distribution can the metal fracture be understood deeply.

  11. Changes of Dust Grain Properties Under Particle Bombardment

    Science.gov (United States)

    Pavlů, J.; Richterová, I.; Fujita, D.; Šafránková, J.; Němeček, Z.

    2008-09-01

    The dust in space environments is exposed to particle bombardment. Under an impact of ions, electrons, and photons, the charge of a particular grain changes and, in some cases, the grain structure can be modified. The present study deals with spherical melamine formaldehyde resin grains that are frequently used in many dusty plasmas and microgravity experiments and it concentrates on the influence of the electron beam impact on a grain size. We have performed series of experiments based on the SEM technique. Our investigation has shown that the electron impact can cause a significant increase of the grain size. We discuss changes of material properties and consequences for its applications in laboratory and space experiments.

  12. From protein catalogues towards targeted proteomics approaches in cereal grains

    DEFF Research Database (Denmark)

    Finnie, Christine; Sultan, Abida; Grasser, Klaus D.

    2011-01-01

    Due to their importance for human nutrition, the protein content of cereal grains has been a subject of intense study for over a century and cereal grains were not surprisingly one of the earliest subjects for 2D-gel-based proteome analysis. Over the last two decades, countless cereal grain...... proteomes, mostly derived using 2D-gel based technologies, have been described and hundreds of proteins identified. However, very little is still known about post-translational modifications, subcellular proteomes, and protein–protein interactions in cereal grains. Development of techniques for improved...... of proteins. These “next-generation” proteomics studies will vastly increase our depth of knowledge about the processes controlling cereal grain development, nutritional and processing characteristics....

  13. Cyclitols in maturing grains of wheat, triticale and barley

    Directory of Open Access Journals (Sweden)

    Lesław B. Lahuta

    2011-01-01

    Full Text Available In the present study, the feeding of stem-flag leaf-ear explants of wheat, triticale and barley with d-chiro-inositol and d-pinitol was used for modification of the composition of soluble carbohydrates in grains without genetic transformation of plants. Maturing grains indicated ability to uptake exogenously applied cyclitols, not occurring naturally in cereal plants, and synthesized their a-d-galactosides. The pattern of changes in soluble carbohydrates during grain maturation and germination was not disturbed by the uptake and accumulation of cyclitols. Both, d-chiro-inositol and d-pinitol as well as their a-d-galactosides can be an additional pool of soluble carbohydrates accumulated by maturing grains, without decreasing seeds viability. This is the first report indicating the possibility of introduction of cyclitols with potentially human health benefits properties into cereal grains.

  14. Collisions between carbonaceous grains in the interstellar medium

    CERN Document Server

    Papoular, R J

    2004-01-01

    Semi-empirical molecular dynamics is used to simulate hydrocarbon grain sputtering and collisions which are extremely difficult to study experimentally. This microscopic and dynamic approach is particularly suited to high velocity impacts, where target destruction occurs far from equilibrium. A wide variety of processes are encountered, depending on grain size and velocity: vaporization, fragmentation, atomic implantation, sticking, elastic recoil, atomic chemisorption, H abstraction and H2 formation, etc. The impact-velocity threshold is about 10 km/s but complete grain destruction requires much higher velocities and nearly equal grain sizes. The main outcome of strong collisions is vaporization, i.e. formation of small molecules rather than solid fragments; most of the impact energy is carried away by these molecules in the form of kinetic energy. As a consequence, the energy left in the bulk is insufficient for shattering or even thermal processing. Grain size distribution is hardly affected by such collis...

  15. A stalk of grain and light

    Directory of Open Access Journals (Sweden)

    Erín Moure

    2010-11-01

    Full Text Available "Stalk of Grain and Light" is an excerpt from O Resplandor (Toronto: Anansi, forthcoming 2010, a book of poetry that explodes notions of authorship and translation. In it, the heteronymic character Elisa Sampedrín translates from Nichita Stãnescu, though she knows no Romanian, and the orthonymic character Erín Moure translates Paul Celan, using not Celan but English transcreations from the language of Celan by Oana Avasilichioaei which she appropriates and reorganizes to create the true translation of a poem by Paul Celan, which exists only in her mind. In this world where corporations copyright human cells, where academics and libraries appropriate works of writers, and where writing itself - moreso than visual art - is limited by expanded notions of plagiarism and ownership, of continuity of copyright for decades that prevents works from influencing art's future, Moure refutes the idea that writing is inspired out of nowhere. Here it is rooted to human interaction, to love and loss, to the art of others, and is dedicated to creating a world where the free irruption of thought is possible, and lineages are acknowledged.

  16. Deuterium enrichment of the interstellar grain mantle

    CERN Document Server

    Das, Ankan; Chakrabarti, Sandip K

    2015-01-01

    We carry out Monte-Carlo simulation to study deuterium enrichment of interstellar grain mantles under various physical conditions. Based on the physical properties, various types of clouds are considered. We find that in diffuse cloud regions, very strong radiation fields persists and hardly a few layers of surface species are formed. In translucent cloud regions with a moderate radiation field, significant number of layers would be produced and surface coverage is mainly dominated by photo-dissociation products such as, C,CH_3,CH_2D,OH and OD. In the intermediate dense cloud regions (having number density of total hydrogen nuclei in all forms ~ 2 x 10^4 cm^-3), water and methanol along with their deuterated derivatives are efficiently formed. For much higher density regions (~ 10^6 cm^-3), water and methanol productions are suppressed but surface coverage of CO,CO_2,O_2,O_3 are dramatically increased. We find a very high degree of fractionation of water and methanol. Observational results support a high frac...

  17. Dust grains from the heart of supernovae

    CERN Document Server

    Bocchio, M; Schneider, R; Bianchi, S; Limongi, M; Chieffi, A

    2016-01-01

    Dust grains are classically thought to form in the winds of asymptotic giant branch (AGB) stars. However, there is increasing evidence today for dust formation in supernovae (SNe). To establish the relative importance of these two classes of stellar sources of dust, it is important to know the fraction of freshly formed dust in SN ejecta that is able to survive the passage of the reverse shock and be injected in the interstellar medium. We have developed a new code (GRASH\\_Rev) which follows the newly-formed dust evolution throughout the supernova explosion until the merging of the forward shock with the circumstellar ISM. We have considered four well studied SNe in the Milky Way and Large Magellanic Cloud: SN1987A, CasA, the Crab Nebula, and N49. For all the simulated models, we find good agreement with observations and estimate that between 1 and 8$\\%$ of the observed mass will survive, leading to a SN dust production rate of $(3.9 \\pm 3.7) \\times 10^{-4}$ M$_{\\odot}$yr$^{-1}$ in the Milky Way. This value i...

  18. Cast Stainless Steel Ferrite and Grain Structure

    Energy Technology Data Exchange (ETDEWEB)

    Ruud, Clayton O.; Ramuhalli, Pradeep; Meyer, Ryan M.; Mathews, Royce; Diaz, Aaron A.; Anderson, Michael T.

    2012-09-01

    In-service inspection requirements dictate that piping welds in the primary pressure boundary of light-water reactors be subject to a volumetric examination based on the rules contained within the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section XI. The purpose of the inspection is the reliable detection and accurate sizing of service-induced degradation and/or material flaws introduced during fabrication. The volumetric inspection is usually carried out using ultrasonic testing (UT) methods. However, the varied metallurgical macrostructures and microstructures of cast austenitic stainless steel piping and fittings, including statically cast stainless steel and centrifugally cast stainless steel (CCSS), introduce significant variations in the propagation and attenuation of ultrasonic energy. These variations complicate interpretation of the UT responses and may compromise the reliability of UT inspection. A review of the literature indicated that a correlation may exist between the microstructure and the delta ferrite content of the casting alloy. This paper discusses the results of a recent study where the goal was to determine if a correlation existed between measured and/or calculated ferrite content and grain structure in CCSS pipe.

  19. Lipid composition of grains from wild grasses

    Directory of Open Access Journals (Sweden)

    Zydgalo, J. A.

    1995-02-01

    Full Text Available Physicochemical characteristics, fatty acid and sterol composition were studied in grains of Agropyron elongatum, Bromus catharticus, Festuca arundinacea, Stipa hyaline and Panicum maximum. The highest protein level was found in A. elongatum. Linoleic and palmitic acids were the predominant fatty acids in all species, β-sitosterol was by far the most prominent sterol component in all samples, while Δ7-stigmasterol was detected in only trace amounts.

    Se estudió las características físico-químicas, la composición de ácidos grasos y esteroles de Agropyron elongatum, Bromus catharticus, Festuca arundinacea, Stipa hialina y Panicum maximum. Los niveles más altos de proteínas fueron encontrados en A. elongatum. Dentro de los ácidos grasos el linoleico y el palmítico fueron los predominantes. En todas las muestras el β-sitosterol fue el esterol que se presentó en mayor cantidad, mientras que el Δ7-estigmasterol fue detectado en cantidades trazas.

  20. Dust grains from the heart of supernovae

    Science.gov (United States)

    Bocchio, Marco; Marassi, Stefania; Schneider, Raffaella; Bianchi, Simone; Limongi, Marco; Chieffi, A.

    2016-06-01

    Dust grains are classically thought to form in the winds of asymptotic giant branch (AGB) stars. However, there is increasing evidence today for dust formation in supernovae (SNe). To establish the relative importance of these two classes of stellar sources of dust, it is important to know the fraction of freshly formed dust in SN ejecta that is able to survive the passage of the reverse shock and be injected in the interstellar medium. We have developed a new code (GRASH_Rev) which follows the newly-formed dust evolution throughout the supernova explosion until the merging of the forward shock with the circumstellar ISM. We have considered four well studied SNe in the Milky Way and Large Magellanic Cloud: SN1987A, CasA, the Crab Nebula, and N49. For all the simulated models, we find good agreement with observations and estimate that between 1 and 8% of the observed mass will survive, leading to a SN dust production rate of (3.9± 3.7)×10^(-4) MM_{⊙})/yr in the Milky Way. This value is one order of magnitude larger than the dust production rate by AGB stars but insufficient to counterbalance the dust destruction by SNe, therefore requiring dust accretion in the gas phase.