WorldWideScience

Sample records for abnormal grain growth

  1. 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

  2. Dynamic Abnormal Grain Growth in Refractory Metals

    Science.gov (United States)

    Noell, Philip J.; Taleff, Eric M.

    2015-11-01

    High-temperature plastic deformation of the body-centered cubic (BCC) refractory metals Mo and Ta can initiate and propagate abnormal grains at significantly lower temperatures and faster rates than is possible by static annealing alone. This discovery reveals a new and potentially important aspect of abnormal grain growth (AGG) phenomena. The process of AGG during plastic deformation at elevated temperatures, termed dynamic abnormal grain growth (DAGG), was observed at homologous temperatures between 0.52 and 0.72 in both Mo and Ta sheet materials; these temperatures are much lower than those for previous observations of AGG in these materials during static annealing. DAGG was used to repeatedly grow single crystals several centimeters in length. Investigations to date have produced a basic understanding of the conditions that lead to DAGG and how DAGG is affected by microstructure in BCC refractory metals. The current state of understanding for DAGG is reviewed in this paper. Attention is given to the roles of temperature, plastic strain, boundary mobility and preexisting microstructure. DAGG is considered for its potential useful applications in solid-state crystal growth and its possibly detrimental role in creating undesired abnormal grains during thermomechanical processing.

  3. Abnormal grain growth in Ni-5at.%W

    Science.gov (United States)

    Witte, M.; Belde, M.; Barrales Mora, L.; de Boer, N.; Gilges, S.; Klöwer, J.; Gottstein, G.

    2012-12-01

    The growth of abnormally large grains in textured Ni-5at.%W substrates for high-temperature superconductors deteriorates the sharp texture of these materials and thus has to be avoided. Therefore the growth of abnormal grains is investigated and how it is influenced by the grain orientation and the annealing atmosphere. Texture measurements and grain growth simulations show that the grain orientation only matters so far that a high-angle grain boundary exists between an abnormally growing grain and the Cube-orientated matrix grains. The annealing atmosphere has a large influence on abnormal grain growth which is attributed to the differences in oxygen partial pressure.

  4. Topological and metrical aspects of normal and abnormal grain growth

    Directory of Open Access Journals (Sweden)

    Paulo Rangel Rios

    2007-12-01

    Full Text Available Grain growth theories normally describe a grain using the concept of ‘grain radius’. However, this assumption bypasses all topological information relating to the grain, viz., the number of its faces, edges, etc. This study, by contrast, introduces a new methodology, treating normal and abnormal grain growth in three dimensions in terms of both metrical and topological properties of the grains.

  5. 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.

  6. The Effects of Grain Size and Texture on Dynamic Abnormal Grain Growth in Mo

    Science.gov (United States)

    Noell, Philip J.; Taleff, Eric M.

    2016-07-01

    This is the first report of abnormal grain morphologies specific to a Mo sheet material produced from a commercial-purity arc-melted ingot. Abnormal grains initiated and grew during plastic deformation of this material at temperatures of 1793 K and 1813 K (1520 °C and 1540 °C). This abnormal grain growth during high-temperature plastic deformation is termed dynamic abnormal grain growth, DAGG. DAGG in this material readily consumes nearly all grains near the sheet center while leaving many grains near the sheet surface unconsumed. Crystallographic texture, grain size, and other microstructural features are characterized. After recrystallization, a significant through-thickness variation in crystallographic texture exists in this material but does not appear to directly influence DAGG propagation. Instead, dynamic normal grain growth, which may be influenced by texture, preferentially occurs near the sheet surface prior to DAGG. The large grains thus produced near the sheet surface inhibit the subsequent growth of the abnormal grains produced by DAGG, which preferentially consume the finer grains near the sheet center. This produces abnormal grains that span the sheet center but leave unconsumed polycrystalline microstructure near the sheet surface. Abnormal grains are preferentially oriented with the new evidence that boundary curvature is the primary driving force for DAGG in Mo.

  7. Investigation of Abnormal Grain Growth in Sintered Nd-Fe-B Permanent Magnet

    Institute of Scientific and Technical Information of China (English)

    Liu Guozheng; Liu Shufeng; Wu Bin; Lu Weidong; Zhao Mingjing; Lu Fuqiang; Zhao Ruijin

    2004-01-01

    The abnormal growth of grains of sintering Nd13.6 Dy0.4 Fe79.5 B6.5 magnets were investigated in low oxygen manufacturing process.The abnormal growth of grains occurs easily when the sintering temperature is higher than 1080℃ during the manufacture process.In the magnets, the oxygen content is less than 700 × 10-6 and the average particle size of powder is smaller than 4 μm.The squareness of demagnetization curve of magnet is deteriorated.For high performance magnets, the abnormal growth grain should be avoided by selecting a suitable sintering temperature.

  8. Abnormal grain growth effects on the mechanical behavior of Ni electrodeposits

    Energy Technology Data Exchange (ETDEWEB)

    Arnould, O. [LMT-Cachan, ENS Cachan/CNRS-UMR 8535/Univ. Paris VI, Cachan (France); Lab. de Mecanique et Genie Civil, Univ. Montpellier II, Montpellier (France); Hubert, O.; Hild, F. [LMT-Cachan, ENS Cachan/CNRS-UMR 8535/Univ. Paris VI, Cachan (France)

    2004-07-01

    The study deals with the long-term reliability of a high precision pressure sensor using bellows. They are mainly made of electroplated Ni whose thermal stability is investigated by DSC. EBSD measurements and SEM observations give some evidence for an abnormal grain growth mechanism whose effects on the elasto-plastic properties of the Ni deposit are experimentally investigated. Abnormal grain growth leads to an increase in the elastic modulus and a strong decrease in the yield strength. (orig.)

  9. Interaction Between Second-Phase Particle Dissolution and Abnormal Grain Growth in an Austenitic Stainless Steel

    Directory of Open Access Journals (Sweden)

    J.C. Dutra

    2002-09-01

    Full Text Available The continuing development of stainless steels has resulted in complex steel compositions with substantial amounts of alloying elements. The benefits of such additions invariably come attached to unavoidable disadvantages. One of the most critical item is the potential microstructural instability of the material. Alloying elements may be in a supersaturated solid solution, in which the precipitation of carbides, nitrides, borides and intermetallic phases occurs in a wide range of temperatures. In order to dissolve the mentioned precipitates, solution annealing is commonly performed. However, at the temperature range in which this treatment is carried out, the onset of abnormal grain growth can occur. The interaction between the dissolution of these second-phase particles and the occurrence of abnormal grain growth is investigated in this work. This study also shows that the thermodynamics and the kinetics of dissolution of precipitates may be used to predict whether abnormal grain growth takes place.

  10. The role of abnormal grain growth on solid-state dewetting kinetics

    International Nuclear Information System (INIS)

    Continuous thin films of Pt on A-plane (112¯0) sapphire substrates were dewetted to characterize the morphological evolution and dewetting kinetics at 800 °C using an oxygen partial pressure of 10−20 atm. Hole growth was studied, focusing on partially dewetted samples. Four different low-index orientation relationships were found between the Pt and sapphire substrate by electron backscattered diffraction combined with transmission electron diffraction patterns. Abnormal grains adjacent to the holes with a small deviation from one of the low-index orientation relationships were observed. The difference in the heights of the abnormal grains adjacent to the holes (rim-height) is influenced by the initial position of the hole, and the existence of grains with a low-energy interface orientation relationship, and not only by diffusivity rates dictated by surface orientation as described in existing edge-retraction models. The existence of low-index orientation relationships is seen as the driving force for abnormal grain growth in the vicinity of the holes, and is a dominant factor in controlling the dewetting rate of thin metal films on oxide surfaces

  11. 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.

  12. Mitigating Abnormal Grain Growth for Friction Stir Welded Al-Li 2195 Spun Formed Domes

    Science.gov (United States)

    Chen, Po-Shou; Russell, Carolyn

    2012-01-01

    Formability and abnormal grain growth (AGG) are the two major issues that have been encountered for Al alloy spun formed dome development using friction stir welded blanks. Material properties that have significant influence on the formability include forming range and strain hardening exponent. In this study, tensile tests were performed for two 2195 friction stir weld parameter sets at 400 F to study the effects of post weld anneal on the forming range and strain hardening exponent. It was found that the formability can be enhanced by applying a newly developed post weld anneal to heat treat the friction stir welded panels. This new post weld anneal leads to a higher forming range and much improved strain hardening exponent. AGG in the weld nugget is known to cause a significant reduction of ductility and fracture toughness. This study also investigated how AGG may be influenced by the heating rate to the solution heat treatment temperature. After post-weld annealing, friction stir welds were strained to 15% and 39% by compression at 400 F before they were subjected to SHT at 950 F for 1 hour. Salt bath SHT is very effective in reducing the grain size as it helps arrest the onset of AGG and promote normal recrystallization and grain growth. However, heat treating a 18 ft dome using a salt bath is not practical. Efforts are continuing at Marshall Space Flight Center to identify the welding parameters and heat treating parameters that can help mitigate the AGG in the friction stir welds.

  13. Abnormal grain growth in sintered YBa2Cu3O7-δ nanocrystalline powders produced by high energy ball milling

    International Nuclear Information System (INIS)

    The sintering and crystal growth of YBa2Cu3O7-δ (123) nanocrystalline powders produced by high energy ball milling has been studied. After rapid densification, microstructural examination indicates for the first time the occurrence of an abnormal grain growth phenomenon or secondary recrystallization (SR). This phenomenon was not observed during the sintering of unmilled YBa2Cu3O7-δ powders. Optical, TEM and calorimetric techniques were used to characterize the occurrence of SR in this system. Following an incubation period where normal grain growth is observed, large tabular grains progressively appear in the microstructure. Their length and shape factors (s=Lenght/Width) measured on a cross section can reach values as high as 0.5 mm and 46 respectively after 6 h. at 950 C. The bimodal grain size distribution typical of SR processes evolves toward a single distribution of large grains when the faster growing abnormal grains consume the remaining population of normal grains. The observations indicate that SR in YBa2Cu3O7-δ is the result of a combined effect of milling and the presence of a small amount of transient yttrium deficient liquid that wets some of the grain boundaries during the sintering step. The liquid originates either from an incomplete synthesis of the 123 compound and/or by air contamination of the milled powders. The control of this abnormal grain growth is of interest for the formation of bulk textured large grain microstructure desirable for the attainment of good superconducting properties. (orig.)

  14. Effect of second phase particles topology on the onset temperature of abnormal grain growth in Fe - 3%Si steels

    Directory of Open Access Journals (Sweden)

    Stoyka, V.

    2008-01-01

    Full Text Available The relations between regimes of dynamic annealing, state of secondary particles system and the onset temperature of abnormal grain growth are investigated. Two distinguish types of Fe-3%Si grain-oriented steels, after one and two stage cold rolling, were studied. The second phase particles remain unaffected in first type of steel during the heat treatment. Vice versa, the increased density of second phases was observed after annealing in the second type of the investigated materials. It is shown that start/onset of abnormal grain growth strongly depends on both volume fraction of second phase particles and annealing temperature. Texture and magnetic properties of the investigated samples are investigated within the current study.

  15. 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.)

  16. 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.

  17. Study on grain growth of fine grained WC-Co hardmetal by numerical calculation

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, N. [Kobe Steel, Ltd., Kobe (Japan); Hayashi, K. [The University of Tokyo, Tokyo (Japan). Institute of industrial Science

    2000-12-15

    This paper reviews our simulation study by numerical calculation based on two-, three- and multi-grain-size models on WC grain growth in fine grained WC-Co hardmetal doped with VC. The study aimed to presume or predict the following: (1) the cause and conditions for the abnormal grain growth which occurs in some cases in the fine grained hardmetal prepared from fine WC powders with mean grain size below about 0.2{mu}m, and (2) how the mean grain size of the hardmetal varies with decreasing mean grain size of the WC starting powder to 0.1 pm or nano-meter size. The calculation results by these three kinds of models suggested the following, respectively: (1) the occurrence of the abnormal grain growth is generally substantial for WC starting powder with bimodal size-distribution and mean gram size below 0.1 - 0.2{mu}m, and not due to the non-uniform distribution of the grain growth inhibitor, (2) the introduction of middle grains caused the disappearance of small (fine) grains during sintering, leading to abruptly increase of the mean grain size of alloy, and (3) the mean grain size of alloy becomes so large as about 0.3 - 0.4{mu}m, even when the WC starting powders with nano-size as well as 0.1 {mu}m are used. (author)

  18. Characterization of abnormal grain coarsening in Alloy 718

    Directory of Open Access Journals (Sweden)

    Watson Richard

    2014-01-01

    Full Text Available Even though the phenomenon of abnormal grain coarsening (AGC or “exploded grains” has been known to occur in Alloy 718 industrial forgings there is still no satisfactory explanation for it. For this reason, detailed microstructure analysis has been carried out in normal and abnormal regions. Electron Backscatter Diffraction (EBSD was employed to determine grain size, boundary distribution and measure stored energy, while backscattered imagining in a FEGSEM was used to measure δ precipitate size and morphology. It was found that abnormal regions show almost 3 times as many twin boundaries compared to a normal region. In addition, the δ phase morphologies differ very significantly when comparing these two different regions. Normal regions display δ phase with a plate like nature, whereas in abnormal regions, δ particles appear to be more spherical. Furthermore, there are clear indications of differences in δ volume fractions between the two regions. Whilst in normal regions the δ phase is found predominantly at grain boundaries, in abnormal regions the δ is also found within grains. Both backscatter images and EBSD scans indicate that there are higher levels of stored energy within the normal regions, compared to the abnormal regions. These observations suggest that AGC occurs in regions where dynamic recrystallization does not happen and where recrystallization during solution heat treatment is affected by the local particle distribution.

  19. Austenite grain growth calculation of 0.028% Nb steel

    Directory of Open Access Journals (Sweden)

    Priadi D.

    2011-01-01

    Full Text Available Modeling of microstructural evolution has become a powerful tool for materials and process design by providing quantitative relationships for microstructure, composition and processing. Insufficient attention has been paid to predicting the austenite grain growth of microalloyed steel and the effect of undissolved microalloys. In this research, we attempted to calculate a mathematical model for austenite grain growth of 0.028% Nb steel, which can account for abnormal grain growth. The quantitative calculation of austenite grain growth generated from this model fit well with the experimental grain growth data obtained during reheating of niobium steels. The results of this study showed that increasing the temperature increases the austenite grain size, with a sharp gradient observed at higher temperatures.

  20. Grain nucleation and growth during phase transformations

    DEFF Research Database (Denmark)

    Offerman, S.E.; Dijk, N.H. van; Sietsma, J.;

    2002-01-01

    of individual grains. Our measurements show that the activation energy for grain nucleation is at least two orders of magnitude smaller than that predicted by thermodynamic models. The observed growth curves of the newly formed grains confirm the parabolic growth model but also show three...... fundamentally different types of growth. Insight into the grain nucleation and growth mechanisms during phase transformations contributes to the development of materials with optimal mechanical properties....

  1. 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.

  2. Abnormal mandibular growth and the condylar cartilage.

    Science.gov (United States)

    Pirttiniemi, Pertti; Peltomäki, Timo; Müller, Lukas; Luder, Hans U

    2009-02-01

    Deviations in the growth of the mandibular condyle can affect both the functional occlusion and the aesthetic appearance of the face. The reasons for these growth deviations are numerous and often entail complex sequences of malfunction at the cellular level. The aim of this review is to summarize recent progress in the understanding of pathological alterations occurring during childhood and adolescence that affect the temporomandibular joint (TMJ) and, hence, result in disorders of mandibular growth. Pathological conditions taken into account are subdivided into (1) congenital malformations with associated growth disorders, (2) primary growth disorders, and (3) acquired diseases or trauma with associated growth disorders. Among the congenital malformations, hemifacial microsomia (HFM) appears to be the principal syndrome entailing severe growth disturbances, whereas growth abnormalities occurring in conjunction with other craniofacial dysplasias seem far less prominent than could be anticipated based on their often disfiguring nature. Hemimandibular hyperplasia and elongation undoubtedly constitute the most obscure conditions that are associated with prominent, often unilateral, abnormalities of condylar, and mandibular growth. Finally, disturbances of mandibular growth as a result of juvenile idiopathic arthritis (JIA) and condylar fractures seem to be direct consequences of inflammatory and/or mechanical damage to the condylar cartilage. PMID:19164410

  3. Methods of assessing grain-size distribution during grain growth

    DEFF Research Database (Denmark)

    Tweed, Cherry J.; Hansen, Niels; Ralph, Brian

    1985-01-01

    This paper considers methods of obtaining grain-size distributions and ways of describing them. In order to collect statistically useful amounts of data, an automatic image analyzer is used, and the resulting data are subjected to a series of tests that evaluate the differences between two related...... distributions (before and after grain growth). The distributions are measured from two-dimensional sections, and both the data and the corresponding true three-dimensional grain-size distributions (obtained by stereological analysis) are collected. The techniques described here are illustrated by reference to...

  4. Global Goss grain growth and grain boundary characteristics in magnetostrictive Galfenol sheets

    International Nuclear Information System (INIS)

    Single Goss grains were globally grown in magnetostrictive Galfenol thin sheets via an abnormal grain growth (AGG) process. The sample behaves like single crystal Galfenol, exhibiting large magnetostriction along the 〈100〉 axes. Small variations in surface energy conditions, which were governed by different flow rates of 0.5% H2S gas in argon during annealing, had a significant impact of the development of AGG. AGG with a fully developed Goss (011) grain over 95% of the sample surface is very reproducible and feasible for a broad range of annealing conditions. In addition, the 〈100〉 orientation of the single-crystal-like Galfenol sheet aligns exactly with the rolling direction, and produces magnetostriction values of ∼300 ppm. AGG often produces isolated grains inside Goss grains due to anisotropic properties of grain boundaries. To better understand island formation mechanisms, grain orientation and grain boundary characteristics of island grains in Goss-oriented Galfenol thin sheets were also investigated. We examined samples annealed either under an argon atmosphere or under a sulfur atmosphere, and characterized the observed island grain boundaries in terms of grain misorientation angles. Trends in measured and simulated data on misorientation angles indicate that the presence of (001) island grain boundaries with angles higher than 45° can be explained by the high energy grain boundary (HEGB) model, whereas (111) boundaries with intermediate angles (20°–45°) cannot. The role of low energy coincident site lattice (CSL) boundaries on AGG in both annealing cases was found to be negligible. (paper)

  5. 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.

  6. Grain Growth in Collapsing Clouds

    Science.gov (United States)

    Rossi, S. C. F.; Benevides-Soares, P.; Barbuy, B.

    1990-11-01

    RESUMEN. Se ha considerado un proceso de coagulaci6n de granos en nubes colapsantes de diferentes metalicidades. Se aplicaron los calculos al intervalo de densidades n = lO to , forrespondiendo a la fase isotermica de contracci6n de nubes. A lo largo de esta fase en el colap- so, la temperatura es por lo tanto constante, en donde se alcanza T Q lOKpara nubes de metalicidad solar y T 100 K para nubes de baja metalicidad. El tamano final del grano es mayor para las mayores metali- cidades. ABSTRACT. A process of grain coagulation in collapsing clouds of different metallicities is considered. The calculations are applied to the density range n = 1O to , corresponding to the isothermal phase of cloud contraction. Along this phase in the collapse, the temperature is thus a constant, where T % 10 K for solar-metallicity clouds, and T % 100 K for low metallicity clouds is reached. The final grain size is larger for the higher metallicities. Keq : INTERSTELLAR-CLOUDS - INTERSTELLAR-CRAINS

  7. An Atmospheric Structure Equation for Grain Growth

    CERN Document Server

    Ormel, Chris W

    2014-01-01

    We present a method to include the evolution of the grain size and grain opacity $\\kappa_\\mathrm{gr}$ in the equations describing the structure of protoplanetary atmospheres. The key assumption of this method is that a single grain size dominates the grain size distribution at any height $r$. In addition to following grain growth, the method accounts for mass deposition by planetesimals and grain porosity. We illustrate this method by computation of a simplified atmosphere structure model. In agreement with previous works, grain coagulation is seen to be very efficient. The opacity drops to values much below the often-used `ISM-opacities' ($\\sim$$1\\ \\mathrm{cm^2\\ g}^{-1}$) and the atmosphere structure profiles for temperature and density resemble that of the grain-free case. Deposition of planetesimals in the radiative part of the atmosphere hardly influences this outcome as the added surface is quickly coagulated away. We observe a modest dependence on the internal structure (porosity), but show that filling...

  8. 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.

  9. In situ observations of austenite grain growth in Fe-C-Mn-Si super bainitic steel

    Institute of Scientific and Technical Information of China (English)

    Feng Liu; Guang Xu; Yu-long Zhang; Hai-jiang Hu; Lin-xin Zhou; Zheng-liang Xue

    2013-01-01

    In situ observations of austenite grain growth in Fe-C-Mn-Si super bainitic steel were conducted on a high-temperature laser scanning confocal microscope during continuous heating and subsequent isothermal holding at 850, 1000, and 1100◦C for 30 min. A grain growth model was proposed based on experimental results. It is indicated that the austenite grain size increases with austenitizing temperature and holding time. When the austenitizing temperature is above 1100◦C, the austenite grains grow rapidly, and abnormal austenite grains occur. In addition, the eff ect of heating rate on austenite grain growth was investigated, and the relation between austenite grains and bainite morphology after bainitic transformations was also discussed.

  10. Three Dimension Monte Carlo Simulation of Austenite Grain Growth in CGHAZ of an Ultrafine Grain Steel

    Institute of Scientific and Technical Information of China (English)

    Dong CHEN; Yongping LEI; Xiaoyan LI; Yaowu SHI; Zhiling TIAN

    2003-01-01

    In the present research Monte Carlo technique was used to simulate the grain growth in heat-affected zone(HAZ) of an ultrafine grain steel. An experimental data based (EBD) model proposed by Gao was used to establish the relation between tMCS and real time temperature kinetics in our simulation. The simulations give out the evolution of grain structure and grain size distribution in HAZ of the ultrafine grain steel. A Microsoft Window based on computer program for the simulation of grain growth in the HAZ of weldment in three dimensions has been developed using Monte Carlo technique. For the system, inputting the temperature field data and material properties, the evolution of grain structure, both image of simulated grain structure and numerical datum reflecting grain size distribution can be produced by the program. The system was applied to the ultrafine grain steel welding, and the simulated results show that the ultrafine grain steel has large tendency of grain growth.

  11. Kinetics of austenite grain growth in medium-carbon niobium-bearing steel

    Institute of Scientific and Technical Information of China (English)

    Ying-li ZHAO; Jie SHI; Wen-quan CAO; Mao-qiu WANG; Gang XIE

    2011-01-01

    In order to locate a reasonable heating system, the austenite grain growth behavior of Nb microalloyed medium carbon steel has been experimentally studied at various austenitizing temperatures and for different holding times. It is indicated that austenite grain growth increases with increasing austenitizing temperatures and holding times. Particularly when the austenitizing temperature was above 1100 ℃, austenite grains grew rapidly, and an abnormal austenite grain growth was observed. When the austenitizing temperature was lower than 1100 ℃, austenite grain size and growth rate were small. The activation energy of grain growth in the tested steel is 397 679.5 J/mol. To ensure an absence of coarse grains in microstructures, the heating technology of the tested steel should be controlled for 1 h at 1100 ℃. The relationships of austenite average grain size with soaking temperature and time of tested steel were obtained by mathematical calculation, and austenite average grain size was found to be in agreement with the measured size for different holding times.

  12. 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. PMID:27282392

  13. Abnormal sex chromosome constitution and longitudinal growth

    DEFF Research Database (Denmark)

    Aksglaede, Lise; Skakkebaek, Niels E; Juul, Anders

    2008-01-01

    Growth is a highly complex process regulated by the interaction between sex steroids and the GH IGF-axis. However, other factors such as sex chromosome-related genes play independent roles.......Growth is a highly complex process regulated by the interaction between sex steroids and the GH IGF-axis. However, other factors such as sex chromosome-related genes play independent roles....

  14. 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.)

  15. Description of Aphelenchoides besseyi from Abnormal Rice with 'Small Grains and Erect Panicles' Symptom in China

    Institute of Scientific and Technical Information of China (English)

    LIN Mao-song; DING Xiao-fan; WANG Zi-ming; ZHOU Feng-ming; LIN Na

    2005-01-01

    The abnormal rice with small grains and erect panicles were found on a large scale in China, which showed shortend rice panicle and decreased number of grains in comparison with normal rice, and the grain was small and black-brown, and some of them were distorted, while the flag leaf was normal. A kind of nematode of Aphelenchoides was isolated from the grains of rice variety and up to 74 in single grain, 92 percent of the grains tested had nematodes in the infested panicles. The diagnosis characters of nematode include lateral fields about one-fourth as wide as body, with 4 incisures. The terminus bears a mucro of diverse shape with 3-4 pointed processes. The female post-vulval uterine sac extends less than 50% of distance from vulva to anus, no sperm in it.Oocytes usually arrange in 2-4 rows. The male spicules have a moderately developed rostrum. Morphological measurements showed it to be conspecific with Aphelenchoides besseyi Christie, 1942.

  16. Competitive growth of high purity aluminum grains in directional solidification

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jiao; SHU Da; WANG De-lin; SUN Bao-de; CHEN Gang

    2006-01-01

    A self-made directional solidification setup was used to prepare high purity aluminum ingots of 100mm in diameter. The morphology of the growth interface was detected by SEM and AFM, and the grain lattice orientation was detected by XRD. The results indicate that the grains suffer competitive growth under any conditions in experiments. The lattice orientation of the preferred grains is determined by the flow field above the solid-liquid interface. The horizontal lattice position does not change during the growth process. However, the lattice orientation in the growth direction varies with the growth velocity and approaches to [100]gradually during the growth process.

  17. 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.

  18. Normal and Abnormal Country Growth Behavior: Country Classification and Ranking

    OpenAIRE

    William R. DiPietro

    2001-01-01

    It is common to classify human behavior as normal or abnormal, but, what about economic behavior? What is a normal growth path for an economy over time? What is an erratic or eccentric growth path? In order to address these basic or primordial questions, eight possible growth states are defined. The countries in the world are classified into these growth states in each of six five-year periods beginning in 1967 and ending in 1996. Provided all the data is available, the results yield a growth...

  19. 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...

  20. Analysis of Grain Growth in Strain Annealing of Low Carbon Steel

    Energy Technology Data Exchange (ETDEWEB)

    An, Sung Kwon [Union Steel MFG. Co., Ltd., Busan (Korea, Republic of); Hong, Seung Hyun [Hyundai Motor Company and Kia Motors Corporation, Hwasung (Korea, Republic of)

    2007-10-15

    A study has been made of the grain growth in IF steel during strain annealing. A 92.3% cold rolled and annealed IF steel sheet was temper rolled by 0.4% and subsequently annealed at 670, 750 and 850 .deg. C for various time periods in 25%H{sub 2}+75%N{sub 2}. The grains occasionally started to grow abnormally near the surface and grew into the center during strain annealing. The pole figure and EBSD measurements showed that the abnormally grown grains did not have any orientation relation with the primary recrystallization texture before temper rolling. Thus, the major coarsening mechanism was regarded to be the strain induced grain boundary migration rather than grain boundary characteristics. The permeability increased initially and then decreased along with the increased of grain size, therefore there existed an optimum grain size showing maximum value of permeability. The maximum permeability was measured up to be 13,000, then optimum grain size is 83 {mu}m at 850 .deg. C for 30 min.

  1. Runaway growth of fractal dust grains

    CERN Document Server

    Mattsson, Lars

    2015-01-01

    Fractal grains have large surface area, which leads to more efficient condensation. The special limit case where the volume-area ratio is constant (corresponding to, e.g., a very rough grain surface or non-compacts aggregates) is particularly interesting, as well as convenient, from a mathematical point of view. If dust grains from AGB stars have `rough surfaces', it may have important implications for our understanding of dust and wind formation in AGB stars.

  2. Phase field modelling of stressed grain growth: Analytical study and the effect of microstructural length scale

    Energy Technology Data Exchange (ETDEWEB)

    Jamshidian, M., E-mail: mostafa.jamshidian@gmail.com [Department of Mechanical Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Institute of Structural Mechanics, Bauhaus-University Weimar, Marienstrasse 15, 99423 Weimar (Germany); Rabczuk, T., E-mail: timon.rabczuk@uni-weimar.de [Institute of Structural Mechanics, Bauhaus-University Weimar, Marienstrasse 15, 99423 Weimar (Germany); School of Civil, Environmental and Architectural Engineering, Korea University, Seoul (Korea, Republic of)

    2014-03-15

    We establish the correlation between the diffuse interface and sharp interface descriptions for stressed grain boundary migration by presenting analytical solutions for stressed migration of a circular grain boundary in a bicrystalline phase field domain. The validity and accuracy of the phase field model is investigated by comparing the phase field simulation results against analytical solutions. The phase field model can reproduce precise boundary kinetics and stress evolution provided that a thermodynamically consistent theory and proper expressions for model parameters in terms of physical material properties are employed. Quantitative phase field simulations are then employed to investigate the effect of microstructural length scale on microstructure and texture evolution by stressed grain growth in an elastically deformed polycrystalline aggregate. The simulation results reveal a transitional behaviour from normal to abnormal grain growth by increasing the microstructural length scale.

  3. 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.

  4. Abnormal Stability in Growth of Diffusion-Limited Aggregation

    Science.gov (United States)

    Ohta, Shonosuke

    2009-01-01

    An abnormal and unsteady growth of an isotropic cluster in diffusion-limited aggregation (DLA) is observed in stability analyses. Macroscopic fluctuation due to the delay of transition from a dendritic tip to a tip-splitting growth induces the anisotropy of DLA. An asymptotic deformation factor \\varepsilon∞ = 0.0888 is obtained from large DLA clusters. A symmetric oval model proposed from the dual-stability growth of DLA gives an asymptotic fractal dimension of 1.7112 using \\varepsilon∞. The correspondence of this model to the box dimension is excellent.

  5. Modelling grain growth in the framework of Rational Extended Thermodynamics

    Science.gov (United States)

    Kertsch, Lukas; Helm, Dirk

    2016-05-01

    Grain growth is a significant phenomenon for the thermomechanical processing of metals. Since the mobility of the grain boundaries is thermally activated and energy stored in the grain boundaries is released during their motion, a mutual interaction with the process conditions occurs. To model such phenomena, a thermodynamic framework for the representation of thermomechanical coupling phenomena in metals including a microstructure description is required. For this purpose, Rational Extended Thermodynamics appears to be a useful tool. We apply an entropy principle to derive a thermodynamically consistent model for grain coarsening due to the growth and shrinkage of individual grains. Despite the rather different approaches applied, we obtain a grain growth model which is similar to existing ones and can be regarded as a thermodynamic extension of that by Hillert (1965) to more general systems. To demonstrate the applicability of the model, we compare our simulation results to grain growth experiments in pure copper by different authors, which we are able to reproduce very accurately. Finally, we study the implications of the energy release due to grain growth on the energy balance. The present unified approach combining a microstructure description and continuum mechanics is ready to be further used to develop more elaborate material models for complex thermo-chemo-mechanical coupling phenomena.

  6. Effects of Free Surface and Heterogeneous Residual Internal Stress on Stress-Driven Grain Growth in Nanocrystalline Metals

    Directory of Open Access Journals (Sweden)

    F. Wang

    2013-01-01

    Full Text Available By reevaluating the experimental study of Zhang et al. (2005, here we demonstrate that the extent of grain growth, previously proposed to be solely driven by external stress, may have been significantly overestimated. A new physical mechanism, termed as free surface assisted stress-driven grain growth (or self-mechanical annealing, is proposed and discussed in detail. Representing the cooperative effect of free surface and heterogeneous residual internal stress, the proposed mechanism is considered more favorable than the traditional pure stress-driven mechanism for interpreting the abnormal grain growth widely observed in deforming nanocrystalline metals at room temperature.

  7. Lattice Boltzmann models for the grain growth in polycrystalline systems

    Directory of Open Access Journals (Sweden)

    Yonggang Zheng

    2016-08-01

    Full Text Available In the present work, lattice Boltzmann models are proposed for the computer simulation of normal grain growth in two-dimensional systems with/without immobile dispersed second-phase particles and involving the temperature gradient effect. These models are demonstrated theoretically to be equivalent to the phase field models based on the multiscale expansion. Simulation results of several representative examples show that the proposed models can effectively and accurately simulate the grain growth in various single- and two-phase systems. It is found that the grain growth in single-phase polycrystalline materials follows the power-law kinetics and the immobile second-phase particles can inhibit the grain growth in two-phase systems. It is further demonstrated that the grain growth can be tuned by the second-phase particles and the introduction of temperature gradient is also an effective way for the fabrication of polycrystalline materials with grained gradient microstructures. The proposed models are useful for the numerical design of the microstructure of materials and provide effective tools to guide the experiments. Moreover, these models can be easily extended to simulate two- and three-dimensional grain growth with considering the mobile second-phase particles, transient heat transfer, melt convection, etc.

  8. Lattice Boltzmann models for the grain growth in polycrystalline systems

    Science.gov (United States)

    Zheng, Yonggang; Chen, Cen; Ye, Hongfei; Zhang, Hongwu

    2016-08-01

    In the present work, lattice Boltzmann models are proposed for the computer simulation of normal grain growth in two-dimensional systems with/without immobile dispersed second-phase particles and involving the temperature gradient effect. These models are demonstrated theoretically to be equivalent to the phase field models based on the multiscale expansion. Simulation results of several representative examples show that the proposed models can effectively and accurately simulate the grain growth in various single- and two-phase systems. It is found that the grain growth in single-phase polycrystalline materials follows the power-law kinetics and the immobile second-phase particles can inhibit the grain growth in two-phase systems. It is further demonstrated that the grain growth can be tuned by the second-phase particles and the introduction of temperature gradient is also an effective way for the fabrication of polycrystalline materials with grained gradient microstructures. The proposed models are useful for the numerical design of the microstructure of materials and provide effective tools to guide the experiments. Moreover, these models can be easily extended to simulate two- and three-dimensional grain growth with considering the mobile second-phase particles, transient heat transfer, melt convection, etc.

  9. 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...

  10. Effect of ferrite formation on abnormal austenite grain coarsening in low-alloy steels during the hot rolling process

    Science.gov (United States)

    Asahi, Hitoshi; Yagi, Akira; Ueno, Masakatsu

    1998-05-01

    Abnormal coarsening of austenite (γ) grains occurred in low-alloy steels during a seamless pipe hotrolling process. Often, the grains became several hundred micrometers in diameter. This made it difficult to apply direct quenching to produce high-performance pipes. The phenomenon of grain coarsening was successfully reproduced using a thermomechanical simulator, and the factors which affected grain coarsening were clarified. The mechanism was found to be basically strain-induced grain rowth which occurred during reheating at around 930 °C. Furthermore, once a pipe temperature decreased to the dual-phase region after the minimal hot working and prior to the reheating process, the grain coarsening was more pronounced. It was understood that the formation of ferrite along grain boundaries had the role of reducing the migration of grain boundaries into neighboring grains, leaving a strain-free, recrystallized region behind. This abnormal grain coarsening was found to be effectively prevented by an addition of Nb, the content of which varied depending on the C content. The effect of the Nb addition was confirmed by an in-line test.

  11. Dynamic Demonstration 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 we re dynamically demonstrated with 3D graphical display techniques. Based on the p rinciples of grain growth in ceramics, the data of coordination in different ato ms were calculated with Monte-Carlo method at atomistic scale. Realistic images in three-dimension were displayed onto two-dimension monitor by projection, i llumination and atomization, using Visual C++ and OpenGL languages. Different small spheres were used to model different kind of atoms,...

  12. Study of grain growth and thermal stability of nanocrystalline RuAl thin films deposited by magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Guitar, M.A., E-mail: a.guitar@mx.uni-saarland.de [Functional Materials, Materials Science Department, Saarland University, Saarbrücken D-66123 (Germany); Woll, K. [Functional Materials, Materials Science Department, Saarland University, Saarbrücken D-66123 (Germany); Ramos-Moore, E. [Functional Materials, Materials Science Department, Saarland University, Saarbrücken D-66123 (Germany); Facultad de Fisica, Pontificia Universidad Catolica de Chile, Santiago 7820436 (Chile); Mücklich, F. [Functional Materials, Materials Science Department, Saarland University, Saarbrücken D-66123 (Germany)

    2013-01-01

    Special properties of RuAl regarding temperature stability and resistance against corrosion and oxidation, make this intermetallic material suitable to be used under high-temperature and chemically aggressive working conditions. In the present work, the microstructure, thermal stability and grain growth are studied by means of scanning transmission electron microscopy, peak broadening analysis of X-ray diffraction and electron backscatter diffraction. Isothermal kinetics analysis revealed that annealing at temperatures as low as 650 °C does not activate the grain growth, whilst at 700 °C and times lower than 6 h, the growth is induced by a 3D curvature-driven evolution characterised by a monomodal grain size distribution. Higher temperatures and/or annealing times show also abnormal grain growth characterised by a bimodal distribution of the grain sizes, which is correlated with the presence of impurities and grain-orientation-specific driving forces. The corresponding grain boundary activation energy is 145 ± 14 kJ/mol, indicating that the growth is highly dominated by grain-boundary diffusion due to the high volume fraction of grain boundaries compared with coarse-grained polycrystalline materials. - Highlights: ► Thermal stability and grain growth kinetics of RuAl thin films were studied. ► Annealing temperatures between 650 and 750 °C were used for the study. ► Grain size (GS) was determined by image analysis. ► GS was also calculated using X-ray and electron backscatter diffraction measurements. ► The activation energy for grain growth in nanocrystalline RuAl was also estimated.

  13. The accumulation and trapping of grains at planet gaps: effects of grain growth and fragmentation

    CERN Document Server

    Gonzalez, J -F; Maddison, S T; Pinte, C; Ménard, F

    2015-01-01

    We model the dust evolution in protoplanetary disks with full 3D, Smoothed Particle Hydrodynamics (SPH), two-phase (gas+dust) hydrodynamical simulations. The gas+dust dynamics, where aerodynamic drag leads to the vertical settling and radial migration of grains, is consistently treated. In a previous work, we characterized the spatial distribution of non-growing dust grains of different sizes in a disk containing a gap-opening planet and investigated the gap's detectability with the Atacama Large Millimeter/submillimeter Array (ALMA). Here we take into account the effects of grain growth and fragmentation and study their impact on the distribution of solids in the disk. We show that rapid grain growth in the two accumulation zones around planet gaps is strongly affected by fragmentation. We discuss the consequences for ALMA observations.

  14. A new model of grain growth kinetics in UO{sub 2} fuel pellets. Part 1: Grain growth kinetics controlled by grain face bubble migration

    Energy Technology Data Exchange (ETDEWEB)

    Veshchunov, M.S. [Russian Academy of Sciences, Nuclear Safety Institute (IBRAE), 52, B. Tulskaya, Moscow 115191 (Russian Federation)]. E-mail: vms@ibrae.ac.ru

    2005-11-15

    A new mechanism of the lenticular grain face bubble migration which controls the bubble mobility and determines the drag force exerted on the grain boundary, is developed. It is shown that besides a more complicated (so called 'lenticular') shape of grain face bubbles, the migration mechanism of these bubbles might be essentially different from the intragranular bubbles, owing to their specific location on and interaction with a grain boundary. The model is validated against tests on grain growth kinetics during steady irradiation exposure and during post-irradiation annealing of UO{sub 2} fuel samples, and allows explanation of a strong retarding effect of irradiation on the grain growth observed in these tests.

  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. Kinetics of Grain Growth in 718 Ni-Base Superalloy

    Directory of Open Access Journals (Sweden)

    Huda Z.

    2014-10-01

    Full Text Available The Haynes® 718 Ni-base superalloy has been investigated by use of modern material characterization, metallographic and heat treatment equipment. Grain growth annealing experiments at temperatures in the range of 1050 – 1200 oC (1323–1473K for time durations in the range of 20 min-22h have been conducted. The kinetic equations and an Arrhenius-type equation have been applied to compute the grain-growth exponent n and the activation energy for grain growth, Qg, for the investigated alloy. The grain growth exponent, n, was computed to be in the range of 0.066-0.206; and the n values have been critically discussed in relation to the literature. The activation energy for grain growth, Qg, for the investigated alloy has been computed to be around 440 kJ/mol; and the Qg data for the investigated alloy has been compared with other metals and alloys and ceramics; and critically analyzed in relation to our results.

  17. Austenite Grain Growth and Precipitate Evolution in a Carburizing Steel with Combined Niobium and Molybdenum Additions

    Science.gov (United States)

    Enloe, Charles M.; Findley, Kip O.; Speer, John G.

    2015-11-01

    Austenite grain growth and microalloy precipitate size and composition evolution during thermal processing were investigated in a carburizing steel containing various additions of niobium and molybdenum. Molybdenum delayed the onset of abnormal austenite grain growth and reduced the coarsening of niobium-rich precipitates during isothermal soaking at 1323 K, 1373 K, and 1423 K (1050 °C, 1100 °C, and 1150 °C). Possible mechanisms for the retardation of niobium-rich precipitate coarsening in austenite due to molybdenum are considered. The amount of Nb in solution and in precipitates at 1373 K (1100 °C) did not vary over the holding times evaluated. In contrast, the amount of molybdenum in (Nb,Mo)C precipitates decreased with time, due to rejection of Mo into austenite and/or dissolution of fine Mo-rich precipitates. In hot-rolled alloys, soaking in the austenite regime resulted in coarsening of the niobium-rich precipitates at a rate that exceeded that predicted by the Lifshitz-Slyozov-Wagner relation for volume-diffusion-controlled coarsening. This behavior is attributed to an initial bimodal precipitate size distribution in hot-rolled alloys that results in accelerated coarsening rates during soaking. Modification of the initial precipitate size distribution by thermal processing significantly lowered precipitate coarsening rates during soaking and delayed the associated onset of abnormal austenite grain growth.

  18. Austenitic grain growth study in a low carbon HSLA steel; Estudio del crecimiento de grano de la fase austenitica en un acero HSLA de bajo contenido en carbono

    Energy Technology Data Exchange (ETDEWEB)

    Illescas, S.; Fernandez, J.; Guilemany, J. M.

    2008-07-01

    The austenitic grain growth has been studied in a low carbon HSLA steel using a model of simples carbides and nitrides. A quantitative criterion for abnormal grain growth has been established and the optimal conditions of heat treatment have also been found. these optimal conditions are the time and the temperature that provide the minimum homogeneous grain size. This optimisation is important because the grain growth at the beginning of the {gamma}{yields}{alpha} determines the development of this, and the final properties of the structure. (Author) 11 refs.

  19. The pleiotropic ABNORMAL FLOWER AND DWARF1 affects plant height, floral development and grain yield in rice

    Institute of Scientific and Technical Information of China (English)

    Deyong Ren; Li Zhu; Zhenyu Gao; Guojun Dong; Guangheng Zhang; Longbiao Guo; Dali Zeng; and Qian Qian; Yuchun Rao; Liwen Wu; Qiankun Xu; Zizhuang Li; Haiping Yu; Yu Zhang; Yujia Leng; Jiang Hu

    2016-01-01

    Moderate plant height and successful establish-ment of reproductive organs play pivotal roles in rice grain production. The molecular mechanism that controls the two aspects remains unclear in rice. In the present study, we characterized a rice gene, ABNORMAL FLOWER AND DWARF1 (AFD1) that determined plant height, floral development and grain yield. The afd1 mutant showed variable defects including the dwarfism, long panicle, low seed setting and reduced grain yield. In addition, abnormal floral organs were also observed in the afd1 mutant including slender and thick hulls, and hull-like lodicules. AFD1 encoded a DUF640 domain protein and was ex-pressed in all tested tissues and organs. Subcellular localization showed AFD1-green fluorescent fusion protein (GFP) was localized in the nucleus. Meantime, our results suggested that AFD1 regulated the expression of cell division and expansion related genes.

  20. The pleiotropic ABNORMAL FLOWER AND DWARF1 affects plant height, floral development and grain yield in rice

    Science.gov (United States)

    Ren, Deyong; Rao, Yuchun; Wu, Liwen; Xu, Qiankun; Li, Zizhuang; Yu, Haiping; Zhang, Yu; Leng, Yujia; Hu, Jiang; Zhu, Li; Gao, Zhenyu; Dong, Guojun; Zhang, Guangheng; Guo, Longbiao

    2016-01-01

    Abstract Moderate plant height and successful establishment of reproductive organs play pivotal roles in rice grain production. The molecular mechanism that controls the two aspects remains unclear in rice. In the present study, we characterized a rice gene, ABNORMAL FLOWER AND DWARF1 (AFD1) that determined plant height, floral development and grain yield. The afd1 mutant showed variable defects including the dwarfism, long panicle, low seed setting and reduced grain yield. In addition, abnormal floral organs were also observed in the afd1 mutant including slender and thick hulls, and hull‐like lodicules. AFD1 encoded a DUF640 domain protein and was expressed in all tested tissues and organs. Subcellular localization showed AFD1‐green fluorescent fusion protein (GFP) was localized in the nucleus. Meantime, our results suggested that AFD1 regulated the expression of cell division and expansion related genes. PMID:26486996

  1. Strain Rates and Grain Growth in Al 5754 and Al 6061 Friction Stir Spot Welds

    Science.gov (United States)

    Gerlich, A.; Yamamoto, M.; North, T. H.

    2007-06-01

    The stir zone temperature and microstructures are compared in friction stir spot welds produced in Al 5754 and Al 6061 alloys. Electron backscattered diffraction was used to determine the relationship between tool rotation speed during welding and final stir zone grain size. Comparison of the grain sizes in rapidly quenched welds with those in air-cooled joints confirmed that grain growth occurred only in Al 6061 spot welds. There was no evidence of abnormal grain growth in the stir zones of Al 6061 welds; the final grain size could be represented using an Arrhenius equation. The strain rates during welding were determined by incorporating the stir zone temperature and average subgrain sizes in quenched spot welds in the Zener-Hollomon relation. When the tool rotation speed increased from 750 to 3000 RPM, the strain rate values ranged from 180 to 497 s-1 in Al 5754 spot welds and from 55 to 395 s-1 in Al 6061 spot welds. It is suggested that a no-slip boundary condition may be appropriate during numerical modeling of Al 5754 and 6061 friction stir spot welding. This is not the case during Al 7075, Al 2024, and Mg-alloy AZ91 spot welding because spontaneous melting facilitates slippage at the tool contact interface.

  2. Giant secondary grain growth in Cu films on sapphire

    Directory of Open Access Journals (Sweden)

    David L. Miller

    2013-08-01

    Full Text Available Single crystal metal films on insulating substrates are attractive for microelectronics and other applications, but they are difficult to achieve on macroscopic length scales. The conventional approach to obtaining such films is epitaxial growth at high temperature using slow deposition in ultrahigh vacuum conditions. Here we describe a different approach that is both simpler to implement and produces superior results: sputter deposition at modest temperatures followed by annealing to induce secondary grain growth. We show that polycrystalline as-deposited Cu on α-Al2O3(0001 can be transformed into Cu(111 with centimeter-sized grains. Employing optical microscopy, x-ray diffraction, and electron backscatter diffraction to characterize the films before and after annealing, we find a particular as-deposited grain structure that promotes the growth of giant grains upon annealing. To demonstrate one potential application of such films, we grow graphene by chemical vapor deposition on wafers of annealed Cu and obtain epitaxial graphene grains of 0.2 mm diameter.

  3. Microstructure Evolution and Grain Growth Kinetics in Annealed Nanocrystalline Chromium

    Energy Technology Data Exchange (ETDEWEB)

    Chojnowski, Grzegorz [Warsaw University; Przenioslo, Radoslaw [Warsaw University; Sosnowska, Izabela [Warsaw University; Bukowski, Mirko [University of Saarbrucken, Saarbrucken, Germany; Natter, Harald [University of Saarbrucken, Saarbrucken, Germany; Hempelmann, Rolf [University of Saarbrucken, Saarbrucken, Germany; Fitch, Andrew [European Synchrotron Radiation Facility (ESRF); Urban, Volker S [ORNL

    2007-01-01

    The kinetics of thermal evolution of the microstructure of nanocrystalline chromium (nano-Cr) has been studied by time-resolved synchrotron radiation techniques: high-resolution powder diffraction and small-angle X-ray scattering (SAXS). The as-prepared electrodeposited nano-Cr with average grain size of 27 nm shows the same bcc structure as {alpha}-Cr. The nano-Cr cubic lattice parameter thermal expansion is the same as that of reference polycrystalline {alpha}-Cr. Annealing of nano-Cr at temperatures above 400 C leads to a grain growth process with the final grain size not exceeding 125 nm even at a temperature of 700 C. The single power-law behavior is observed by SAXS in as-prepared nano-Cr changes during annealing above 400 C. In nano-Cr samples annealed at temperatures between 400 and 700 C, the low-q part of the SAXS signal shows a Porod-type behavior while the high-q part shows a power-law Q-{alpha} with the exponent {alpha} < 4. This effect is probably due to changes of the grain surface roughness during grain growth.

  4. Modeling nano-scale grain growth of intermetallics

    Indian Academy of Sciences (India)

    Mohsen Kazeminezhad

    2009-02-01

    The Monte Carlo simulation is utilized to model the nano-scale grain growth of two nanocrystalline materials, Pd81Zr19 and RuAl. In this regard, the relationship between the real time and the time unit of simulation, i.e. Monte Carlo step (MCS), is determined. The results of modeling show that with increasing time of heating, the grain sizes of both nano-crystalline materials increased as in the case of conventional materials. Moreover, it is found that for both nano-crystalline materials the relationship between the real time and MCS is in power law form, which is linear for the conventional materials.

  5. Recrystallization and grain growth in NiAl

    Science.gov (United States)

    Haff, G. R.; Schulson, E. M.

    1982-01-01

    Aluminide intermetallics, because of their strength, microstructural stability, and oxidation resistance at elevated temperatures, represent potential structural materials for use in advanced energy conversion systems. This inherent potential of the intermetallics can currently not be realized in connection with the general brittleness of the materials under ambient conditions. It is pointed out, however, that brittleness is not an inherent characteristic. Single crystals are ductile and polycrystals may be, too, if their grains are fine enough. The present investigation is concerned with an approach for reducing material brittleness, taking into account thermal-mechanically induced grain refinement in NiAl, a B2 aluminide which melts at 1638 C and which retains complete order to its melting point. Attention is given to the kinetics of recrystallization and grain growth of warm-worked, nickel-rich material.

  6. Simulation of grain growth in nanocrystalline nickel induced by ion irradiation

    CERN Document Server

    Voegeli, W; Hahn, H

    2003-01-01

    Molecular dynamics simulations of 5 keV cascades in nanocrystalline nickel with grain sizes of 5 and 10 nm are presented. If the spike volume is exceeding the grain size or overlapping the grain boundary (GB) area we observe ion-beam induced grain growth for both grain sizes. In contrast cascades located in the grain volume lead to the formation of vacancies and interstitials, where the latter are mostly accommodated by the GBs upon annealing. Finally, we show that ion-beam induced grain growth is a direct result of recrystallisation of the thermal spike and therefore inherently different to grain growth observed in long time thermal annealing simulations.

  7. The acrophysis: a unifying concept for understanding enchondral bone growth and its disorders. II. Abnormal growth

    Energy Technology Data Exchange (ETDEWEB)

    Oestreich, Alan E. [Department of Radiology, Cincinnati Children' s Hospital Medical Center, 3333 Burnet Avenue, OH 45229-3039, Cincinnati (United States)

    2004-03-01

    In order to discuss and illustrate the effects common to normal and abnormal enchondral bone at the physes and at all other growth plates of the developing child, the term ''acrophysis'' was proposed. Acrophyses include the growth plates of secondary growth centers including carpals and tarsals and apophyses, and the growth plates at the nonphyseal ends of small tubular bones. Abnormalities at acrophyseal sites are analogous to those at the physeal growth plates and their metaphyses. For example, changes relating to the zone of provisional calcification (ZPC) are often important to the demonstration of such similarities. Lead lines were an early example of the concept of analogy from abnormality due to physeal and to acrophyseal disturbance. The ZPC is a key factor in understanding patterns of rickets and its healing. Examples (including hypothyroidism, scurvy and other osteoporosis, Ollier disease, achondroplasia, and osteopetrosis, as well as the family of frostbite, Kashin-Beck disease, and rat bite fever) illustrate the acrophysis principle and in turn their manifestations are explained by that principle. (orig.)

  8. Constitutive modeling of stress-driven grain growth in nanocrystalline metals

    KAUST Repository

    Gürses, Ercan

    2013-02-08

    In this work, we present a variational multiscale model for grain growth in face-centered cubic nanocrystalline (nc) metals. In particular, grain-growth-induced stress softening and the resulting relaxation phenomena are addressed. The behavior of the polycrystal is described by a conventional Taylor-type averaging scheme in which the grains are treated as two-phase composites consisting of a grain interior phase and a grain boundary-affected zone. Furthermore, a grain-growth law that captures the experimentally observed characteristics of the grain coarsening phenomena is proposed. To this end, the grain size is not taken as constant and varies according to the proposed stress-driven growth law. Several parametric studies are conducted to emphasize the influence of the grain-growth rule on the overall macroscopic response. Finally, the model is shown to provide a good description of the experimentally observed grain-growth-induced relaxation in nc-copper. © 2013 IOP Publishing Ltd.

  9. KINETICS OF GRAIN-GROWTH OF YTTRIUM ALUMINUM GARNET FIBERS PREPARED BY SOL-GEL METHOD

    Directory of Open Access Journals (Sweden)

    Tan H.

    2013-12-01

    Full Text Available The yttrium aluminum garnet (YAG long fibers were prepared by the sol-gel method using aluminum chloride, aluminum powder, yttrium oxide and acetic acid as raw materials. The grain growth law is given by Dn – D0n = Kt (D0 = initial grain size, D = average grain size at time t, n = grain growth exponent and K = reaction constant. The grain growth exponent and activation energy of YAG fibers are ≈ 3 and 200 kJ/mol, respectively. The grain-growth behaviors of YAG were influenced by experimental conditions such as raw materials, initial particle size, initial particle distribution, etc.

  10. What is the value of ultrasound soft tissue measurements in the prediction of abnormal fetal growth?

    LENUS (Irish Health Repository)

    Farah, N

    2012-02-01

    Abnormal fetal growth increases the complications of pregnancy not only for the baby but also for the mother. Growth abnormalities also have lifelong consequences. These babies are at increased risk of insulin resistance, diabetes and hypertension later in life. It is important to identify these babies antenatally to optimise their clinical care. Although used extensively antenatally to monitor fetal growth, ultrasound has its limitations. Despite the use of more than 50 different formulae to estimate fetal weight, their performance has been poor at the extremes of fetal weight. Over the past 20 years there has been emerging interest in studying fetal soft tissue measurements to improve detection of growth abnormalities. This review paper outlines the value of soft tissue measurements in identifying fetal growth abnormalities, in estimating fetal weight and in managing diabetes mellitus in pregnancy.

  11. Strain induced grain boundary migration effects on grain growth of an austenitic stainless steel during static and metadynamic recrystallization

    International Nuclear Information System (INIS)

    Static and metadynamic recrystallization of an AISI 304L austenitic stainless steel was investigated at 1100 °C and 10− 2 s− 1 strain rate. The kinetics of recrystallization was determined through double hit compression tests. Two strain levels were selected for the first compression hit: εf = 0.15 for static recrystallization (SRX) and 0.25 for metadynamic recrystallization (MDRX). Both the as-deformed and the recrystallized microstructures were investigated through optical microscopy and electron back-scattered diffraction (EBSD) technique. During deformation, strain induced grain boundary migration appeared to be significant, producing a square-like grain boundary structure aligned along the directions of the maximum shear stresses in compression. EBSD analysis revealed to be as a fundamental technique that the dislocation density was distributed heterogeneously in the deformed grains. Grain growth driven by surface energy reduction was also investigated, finding that it was too slow to explain the experimental data. Based on microstructural results, it was concluded that saturation of the nucleation sites occurred in the first stages of recrystallization, while grain growth driven by strain induced grain boundary migration (SIGBM) dominated the subsequent stages. - Highlights: • Recrystallization behavior of a stainless steel was investigated at 1100 °C. • EBSD revealed that the dislocation density distribution was heterogeneous during deformation. • Saturation of nucleation sites occurred in the first stages of recrystallization. • Strain induced grain boundary migration (SIGBM) effects were significant. • Grain growth driven by SIGBM dominated the subsequent stages

  12. Microstructural Evolutions During Annealing of Plastically Deformed AISI 304 Austenitic Stainless Steel: Martensite Reversion, Grain Refinement, Recrystallization, and Grain Growth

    Science.gov (United States)

    Naghizadeh, Meysam; Mirzadeh, Hamed

    2016-08-01

    Microstructural evolutions during annealing of a plastically deformed AISI 304 stainless steel were investigated. Three distinct stages were identified for the reversion of strain-induced martensite to austenite, which were followed by the recrystallization of the retained austenite phase and overall grain growth. It was shown that the primary recrystallization of the retained austenite postpones the formation of an equiaxed microstructure, which coincides with the coarsening of the very fine reversed grains. The latter can effectively impair the usefulness of this thermomechanical treatment for grain refinement at both high and low annealing temperatures. The final grain growth stage, however, was found to be significant at high annealing temperatures, which makes it difficult to control the reversion annealing process for enhancement of mechanical properties. Conclusively, this work unravels the important microstructural evolution stages during reversion annealing and can shed light on the requirements and limitations of this efficient grain refining approach.

  13. Grain growth in thin Al films during deposition from partially ionized vapor

    Science.gov (United States)

    Gusev, I. V.; Mokhniuk, A. A.

    2016-07-01

    Grain growth in thin Al films during deposition from partially ionized vapor flux with simultaneous self-ion bombardment was studied in this work. The films were deposited at constant ion energy of 940 eV and total specific power of 0.4 W/cm2 while the deposition time t of 6 s to 246 s and the resulting substrate temperature (Ts/Tm of 0.35-0.96) were varied. Thin continuous Al films exhibited normal grain growth through the entire experimental range of deposition time without limitation of grain growth by the film thickness effect. Three kinetic stages of the grain growth were observed within 100 s of deposition time: the first one exhibits very slow grain growth, accelerated grain growth occurs in the second stage and then it rapidly changes to a retardation and stagnation mode in the third stage. Large average grain sizes Dg up to 11.3 μm at film thickness of 1.4 μm and integral grain growth rates up to 0.16 μm/s were observed in this study. The experimental results were evaluated against various mechanisms of inhibition of grain growth. An estimate of the effective activation energy of the grain growth yields a value of 0.27 eV which is lower than that of the bulk Al and much higher than the activation energy of surface self-diffusion on (1 1 1)Al monocrystal. The power law Dg = (k t)0.5 gives good match with experimental results in the initial deposition phase preceding the grain growth retardation, while another model that is based on the grain size dependent pinning force adequately explains the entire grain size dependence on time. It is deemed both ion enhanced film/surface interaction and impurities on one side and thermal grooves on another side contribute to the rapid retardation of the grain grooves commencing the second growth stage.

  14. On grain growth kinetics in two-phase polycrystalline materials through Monte Carlo simulation

    Indian Academy of Sciences (India)

    K R Phaneesh; Anirudh Bhat; Gautam Mukherjee; K T Kashyap

    2013-08-01

    Monte Carlo Potts model simulation was carried out on a 2D square lattice for various surface fractions of second phase particles for over 50,000 iterations. The observations are in good agreement with known theoretical and experimental results with respect to both growth kinetics as well as grain size distribution. Further, the average grain size and the largest grain size were computed for various surface fractions which have indicated normal grain growth and microstructure homogeneity. The surface fraction of the second phase particles interacting with the grain boundaries (), hitherto not computed through the simulation route, is shown to vary inversely as the average grain size due to Zener pinning.

  15. Grain growth of Al-4Cu-Mg alloy during isothermal heat treatment

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The microstructure of an Al-4Cu-Mg alloy during isothermal heat treatment in the Strain Induced Melt Activation (SIMA)process was investigated and the kinetics of grain growth was analyzed. The grain growth during isothermal heat treatment of the Al4Cu-Mg alloy coincided with the Ostwald ripening theory. During isothermal heat treatment, both grain shape and the high volume fraction of solid phase have significant effects on grain growth. Therefore, a new grain growth model based on the Ostwald ripening theory was proposed taking into consideration the grain shape and the volume fraction of solid phase. By comparing the calculated results with the experimental results, it was confirmed that the present model could be applied to grain growth during isothermal heat treatment of the Al-4Cu-Mg alloy in the SIMA process.

  16. Grain size distribution and topology in 3D grain growth simulation with large-scale Monte Carlo method

    Institute of Scientific and Technical Information of China (English)

    Hao Wang; Guo-quan Liu; Xiang-ge Qin

    2009-01-01

    Three-dimensional normal grain growth was appropriately simulated using a Potts model Monte Carlo algorithm.The quasi-stationary grain size distribution obtained from simulation agreed well with the experimental result of pure iron.The Weibull function with a parameter β=2.77 and the Yu-Liu function with a parameter v =2.71 fit the quasi-stationary grain size distribution well.The grain volume distribution is a function that decreased exponentially with increasing grain volume.The distribution of boundary area of grains has a peak at S/=0.5,where S is the boundary area of a grain and is the mean boundary area of all grains in the system.The lognormal function fits the face number distribution well and the peak of the face number distribution is f=10.The mean radius of f=faced grains is not proportional to the face number,but appears to be related by a curve convex upward.In the 2D cross-section,both the perimeter law and the Aboav-Weaire law are observed to hold.

  17. Derivation of Hillert-type 3D grain growth rate model with topological considerations and discussion on its grain size parameter

    Institute of Scientific and Technical Information of China (English)

    Guoquan Liu; Haibo Yu; Xiaoyan Song; Xiangge Qin; Chao Wang

    2004-01-01

    A Hillert-type three-dimensional grain growth rate model was derived through the grain topology-size correlation model,combined with a topology-dependent grain growth rate equation in three dimensions. It shows clearly that the Hillert-type 3D grain growth rate model may also be described with topology considerations of microstructure. The size parameter bearing in the model is further discussed both according to the derived model and in another approach with the aid of quantitative relationship between the grain size and the integral mean curvature over grain surface. Both approaches successfully demonstrate that, if the concerned grains can be well approximated by a space-filling convex polyhedra in shape, the grain size parameter bearing in the Hillert-type 3D grain growth model should be a parameter proportional to the mean grain tangent radius.

  18. A Study of Grain Growth Kinetics in Sintered NdFeB Magnets

    Institute of Scientific and Technical Information of China (English)

    刘湘涟; 何建平; 董清飞; 周寿增

    2001-01-01

    The Nd2Fe14B grain growth kinetics in sintered NdFeB magnets with nominal compositions of Nd30+xDy1.5Fe67.08-xAl0.4B1.02 (%, x=0, 3) was studied. The grain size parameters were determined by means of the linear intercept method on SEM secondary electron images. It is observed that the grain growth process is more sensitive to sintering temperature than to sintering time although the grain size rises with both sintering temperature and time. It is also found that magnets prepared from the pre-alloy powder with a higher oxygen content exhibit a lower grain growth rate and magnets made from the pre-alloy powder with a broader particle size distribution demonstrate a higher grain growth rate. It is believed that the presence of appropriate amounts of Nd oxides effectively impedes the grain growth process and a larger difference in sizes between pre-alloy powder particles significantly accelerates the grain growth process. On the basis of experimental results, the grain growth exponent and the corresponding activation energy were obtained. A possible grain growth mechanism in NdFeB magnets during sintering was briefly discussed.

  19. Abnormal Skeletal Growth in Adolescent Idiopathic Scoliosis Is Associated with Abnormal Quantitative Expression of Melatonin Receptor, MT2

    Directory of Open Access Journals (Sweden)

    Alain Moreau

    2013-03-01

    Full Text Available The defect of the melatonin signaling pathway has been proposed to be one of the key etiopathogenic factors in adolescent idiopathic scoliosis (AIS. A previous report showed that melatonin receptor, MT2, was undetectable in some AIS girls. The present study aimed to investigate whether the abnormal MT2 expression in AIS is quantitative or qualitative. Cultured osteoblasts were obtained from 41 AIS girls and nine normal controls. Semi-quantification of protein expression by Western blot and mRNA expression by TaqMan real-time PCR for both MT1 and MT2 were performed. Anthropometric parameters were also compared and correlated with the protein expression and mRNA expression of the receptors. The results showed significantly lower protein and mRNA expression of MT2 in AIS girls compared with that in normal controls (p = 0.02 and p = 0.019, respectively. No differences were found in the expression of MT1. When dichotomizing the AIS girls according to their MT2 expression, the group with low expression was found to have a significantly longer arm span (p = 0.036. The results of this study showed for the first time a quantitative change of MT2 in AIS that was also correlated with abnormal arm span as part of abnormal systemic skeletal growth.

  20. Verification of topological relationship in 2-D grain growth process by simulation

    Institute of Scientific and Technical Information of China (English)

    Chao Wang; Guoquan Liu; Ya Sun; Xiangge Qin

    2004-01-01

    Behaviors of the quasi-steady state grain size distribution and the corresponding topological relationship were investigated using the Ports Monte Carlo method to simulate the normal grain growth process. The observed quasi-steady state grain size distribution can be well fit by the Weibull function rather than the Hillert distribution. It is also found that the grain size and average number of grain sides are not linearly related. The reason that the quasi-steady state grain size distribution deviates from the Hillert distribution may contribute to the nonlinearity of the relation of the average number of grain sides with the grain size. The results also exhibit the reasonability of the relationship deduced by Mullins between the grain size distribution and the average number of grain sides.

  1. Coincidence grain boundary and role of primary recrystallized grain growth on secondary recrystallization texture evolution in Fe-3%Si alloy

    Energy Technology Data Exchange (ETDEWEB)

    Yoshitomi, Y.; Takahashi, N. (Nippon Steel Corp., Kitakyushu (Japan). Yawata R D Lab.); Ushigami, Y.; Harase, J.; Nakayama, T.; Masui, H. (Nippon Steel Corp., Chiba (Japan). Steel Research Lab.)

    1994-08-01

    Secondary recrystallization behavior in the presence of AlN in Fe-3%Si alloy was investigated with special reference to the influence of primary recrystallized grain growth on secondary recrystallization texture. The more dominant grain growth was marked by the evolution of [110]<001> secondary recrystallized grains in the higher temperature range. In the case of smaller primary recrystallized grains, the [110]<227> secondary recrystallized grains were mainly evolved on annealing at the lower temperature range. The frequency of [Sigma]9 coincidence boundaries in relation to the [110]<001> texture component was higher than that of [Sigma]5 coincidence boundaries in relation to [110]<227> component. The mechanism of these evolutions of secondary recrystallization texture can be explained by the assumption that the [Sigma]5 coincidence boundaries are more mobile than the [Sigma]9 coincidence boundaries in the lower temperature range. The primary recrystallized grain growth is considered to have a role in determining what should be the secondary recrystallization temperature.

  2. Direct observation of 3-D grain growth in Al–0.1% Mn

    DEFF Research Database (Denmark)

    Schmidt, Søren; Olsen, Ulrik Lund; Poulsen, Henning Friis;

    2008-01-01

    Grain growth in an Al-0.1% Mn sample has been measured non-destructively using a three-dimensional X-ray diffraction (3DXRD) microscope. The 3-D grain morphology as well as the crystallographic orientation was determined for 483 grains in the illuminated volume prior to annealing. After annealing...

  3. Influence of Annealing on the Grain Growth and Thermal Diffusivity of Nanostructured YSZ Thermal Barrier Coating

    Institute of Scientific and Technical Information of China (English)

    Na WANG; Chungen ZHOU; Shengkai GONG; Huibin XU

    2006-01-01

    The nanostructured zirconia coatings were deposited by atmospherically plasma spraying. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction were used to investigate the microstructure of the zirconia coatings. Thermal diffusivity values at normal temperatures have been evaluated by laser flash technique. Effect of annealing on the microstructure evolution of the zirconia coating has been performed. The grains and thermal diffusivity are increased with increasing annealing time and temperature.The grain growth is according to the GRIGC (the grain rotation induced grain coalescence) mechanism. The increase in thermal diffusivity is attributed to the grain growth and the decrease in porosity of nanostructured zirconia coatings.

  4. Fast grain growth of olivine in liquid Fe-S and the formation of pallasites with rounded olivine grains

    Science.gov (United States)

    Solferino, Giulio F. D.; Golabek, Gregor J.; Nimmo, Francis; Schmidt, Max W.

    2015-08-01

    Despite their relatively simple mineralogical composition (olivine + Fe-Ni metal + FeS ± pyroxene), the origin of pallasite meteorites remains debated. It has been suggested that catastrophic mixing of olivine fragments with Fe-(Ni)-S followed by various degrees of annealing could explain pallasites bearing solely or prevalently fragmented or rounded olivines. In order to verify this hypothesis, and to quantify the grain growth rate of olivine in a liquid metal matrix, we performed a series of annealing experiments on natural olivine plus synthetic Fe-S mixtures. The best explanation for the observed olivine grain size distributions (GSD) of the experiments are dominant Ostwald ripening for small grains followed by random grain boundary migration for larger grains. Our results indicate that olivine grain growth in molten Fe-S is significantly faster than in solid, sulphur-free metal. We used the experimentally determined grain growth law to model the coarsening of olivine surrounded by Fe-S melt in a 100-600 km radius planetesimal. In this model, an impact is responsible for the mixing of olivine and Fe-(Ni)-S. Numerical models suggest that annealing at depths of up to 50 km allow for (i) average grain sizes consistent with the observed rounded olivine in pallasites, (ii) a remnant magnetisation of Fe-Ni olivine inclusions as measured in natural pallasites and (iii) for the metallographic cooling rates derived from Fe-Ni in pallasites. This conclusion is valid even if the impact occurs several millions of years after the differentiation of the target body was completed.

  5. Strain induced grain boundary migration effects on grain growth of an austenitic stainless steel during static and metadynamic recrystallization

    Energy Technology Data Exchange (ETDEWEB)

    Paggi, A., E-mail: alpaggi@tenaris.com [Tenaris Dalmine R& D, Dalmine S.p.A., Piazza Caduti 6 Luglio 1944 n.1, 24044 Dalmine (Italy); Angella, G.; Donnini, R. [National Research Council (CNR), Institute for Energetics and Interphases (IENI), Via Roberto Cozzi 53, 20125 Milano (Italy)

    2015-09-15

    Static and metadynamic recrystallization of an AISI 304L austenitic stainless steel was investigated at 1100 °C and 10{sup −} {sup 2} s{sup −} {sup 1} strain rate. The kinetics of recrystallization was determined through double hit compression tests. Two strain levels were selected for the first compression hit: ε{sub f} = 0.15 for static recrystallization (SRX) and 0.25 for metadynamic recrystallization (MDRX). Both the as-deformed and the recrystallized microstructures were investigated through optical microscopy and electron back-scattered diffraction (EBSD) technique. During deformation, strain induced grain boundary migration appeared to be significant, producing a square-like grain boundary structure aligned along the directions of the maximum shear stresses in compression. EBSD analysis revealed to be as a fundamental technique that the dislocation density was distributed heterogeneously in the deformed grains. Grain growth driven by surface energy reduction was also investigated, finding that it was too slow to explain the experimental data. Based on microstructural results, it was concluded that saturation of the nucleation sites occurred in the first stages of recrystallization, while grain growth driven by strain induced grain boundary migration (SIGBM) dominated the subsequent stages. - Highlights: • Recrystallization behavior of a stainless steel was investigated at 1100 °C. • EBSD revealed that the dislocation density distribution was heterogeneous during deformation. • Saturation of nucleation sites occurred in the first stages of recrystallization. • Strain induced grain boundary migration (SIGBM) effects were significant. • Grain growth driven by SIGBM dominated the subsequent stages.

  6. Grain growth in U-7Mo alloy: A combined first-principles and phase field study

    Science.gov (United States)

    Mei, Zhi-Gang; Liang, Linyun; Kim, Yeon Soo; Wiencek, Tom; O'Hare, Edward; Yacout, Abdellatif M.; Hofman, Gerard; Anitescu, Mihai

    2016-05-01

    Grain size is an important factor in controlling the swelling behavior in irradiated U-Mo dispersion fuels. Increasing the grain size in U-Mo fuel particles by heat treatment is believed to delay the fuel swelling at high fission density. In this work, a multiscale simulation approach combining first-principles calculation and phase field modeling is used to investigate the grain growth behavior in U-7Mo alloy. The density functional theory based first-principles calculations were used to predict the material properties of U-7Mo alloy. The obtained grain boundary energies were then adopted as an input parameter for mesoscale phase field simulations. The effects of annealing temperature, annealing time and initial grain structures of fuel particles on the grain growth in U-7Mo alloy were examined. The predicted grain growth rate compares well with the empirical correlation derived from experiments.

  7. Nanoscale grain growth behaviour of CoAl intermetallic synthesized by mechanical alloying

    Indian Academy of Sciences (India)

    S N Hosseini; M H Enayati; F Karimzadeh

    2014-05-01

    Grain growth behaviour of the nanocrystalline CoAl intermetallic compound synthesized by mechanical alloying has been studied by isothermal annealing at different temperatures and durations. X-ray diffraction method was employed to investigate structural evolutions during mechanical alloying and annealing processes. The disordered CoAl phase with the grain size of about 6 nm was formed via a gradual reaction during mechanical alloying. The results of isothermal annealing showed that the grain growth behaviour can be explained by the parabolic grain growth law. The grains were at nanometric scale after isothermal annealing up to 0.7 m. The grain growth exponent remained constant above 873 K indicating that grain growth mechanism does not change at high temperatures. The calculated activation energy indicated that the grain growth mechanism in the disordered CoAl phase at high temperatures was diffusing Co and Al atoms in two separate sublattices. Furthermore, an equation has been suggested to describe the grain growth kinetics of nanocrystalline CoAl under isothermal annealing at temperatures above 873 K (/m ≥ 0.5).

  8. Grain growth in calibre rolled Mg–3Al–1Zn alloy and its effect on hardness

    Directory of Open Access Journals (Sweden)

    R.L. Doiphode

    2015-12-01

    Full Text Available Calibre rolling of Mg–3Al–1Zn alloy at 300 °C led to development of fine grain size of 3 µm. Subsequent annealing, from 5 to 6000 minutes at 300–450 °C, revealed faster grain growth initially up to 60 minutes, which became sluggish on prolonged annealing. The time exponent for grain growth kinetics (n suggests bi-linear behaviour with n = 0.11 and 0.008 over these time scales. The activation energy, based on various n values, varied over wide ranges that made the understanding of the mechanisms for grain growth difficult. This problem is explained by concurrent evolution of texture and grain boundary structure. The effect of grain growth on hardness at ambient temperature was found to follow the H–P type relationship.

  9. Dendritic grain growth simulation in weld pool of nickel base alloy

    Institute of Scientific and Technical Information of China (English)

    Zhan Xiaohong; Wei Yanhong; Ma Rui; Dong Zhibo

    2008-01-01

    Dendritic grain growth at the edge of the weld pool is simulated using a stochastic numerical model of cellular automaton algorithm. The grain growth model is established based upon the balance of solute in the solid/liquid interface of the dendrite tip. Considering the complicated nucleation condition and competitive growth, the dendrite morphologies of different nucleation condition are simulated. The simulated results reproduced the dendrite grain evolution process at the edge of the weld pool. It is indicated that the nucleation condition is an important factor influencing the grain morphologies especially the morphologies of secondary and tertiary arms.

  10. Effect of surface roughness on grain growth and sintering of alumina

    Indian Academy of Sciences (India)

    Padmaja Parameswaran Nampi; Shoichi Kume; Yuji Hotta; Koji Watari

    2011-07-01

    The production of ceramic bodies with less surface roughness is industrially important when one considers the aspect of final machining processes. Hence an attempt have been made to study the variation in surface roughness parameters (a, y, z) of alumina having three different kinds of roughness features at different sintering temperatures. Variation in surface roughness properties are also correlated with grain size. z shows significant difference between fine and intermediate surfaces, hence predicts small difference in their microstructural features. As a general trend, average grain size increases with increase in sintering temperature, but wide distribution of grains with enhanced non-uniform grain growth is observed when the surface is coarse. Hence, creation of fine surface in the green body is necessary for homogeneously distributed grains with controlled uniform grain growth. The final roughness and grain size of the sintered alumina depend on the initial surface roughness of the green body.

  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. Relationship between recrystallization, grain growth and creep strength of molybdenum at high temperatures

    International Nuclear Information System (INIS)

    With the aid of earlier and own investigations, the grain growth processes are presented in dependence of the degree of deformation and of the heat treatment, and the temperature regions for crystal recovery, primary recrystallization, permanent grain growth and discontinuous grain growth in the temperature region upto 2,4000C are defined. The creep strength is an important property for the application of molybdenum at high temperatures, especially as a current leading electrode for melting glasses and ceramics. The influence of the initial grain size of molybdenum on the creep rate was determined in the one-sided fixed bending test for the technically interesting grain size range of 10 to 2,000 K/cm2 at temperatures of 1,7500C and times of up 14 days. The relationship of the creep deformation to the measured grain size values is discussed. (orig./LH)

  13. Is abnormal vaginal microflora a risk factor for intrauterine fetal growth restriction?

    Institute of Scientific and Technical Information of China (English)

    NatalijaVedmedovska; Dace Rezeberga; GilbertG G Donders

    2015-01-01

    Objective:To conduct a literature review in search of possible preventable causes for fetal growth restriction.Methods:We performed a systematic literature search regarding abnormal vaginal microflora and fetal growth encompassing the last 27-year (starting from 1986) in PubMed, Embase, and Cochrane Central to study the evidence that abnormal vaginal microflora is may be related to diminished fetal growth or small for date birth.Results:Most of the 14 studies suggested a significant role of vaginal organisms in impaired fetal growth, unrelated to preterm birth. The neonatal outcome has shown to be largely linked to the preventable or foreseeable fetal factors, such as genetic abnormalities, but also ascending intrauterine infections. Our previous work suggested a role of vaginal organisms in adverse pregnancy outcome, not only preterm birth, but also impaired fetal growth.Conclusions:There is a need for cohort studies designed to unravel this link between abnormal microflora and FGR, in order to enable preventive actions to protect these small babies from severe damage and death by early screening and treatment.

  14. Grain growth and morphology of In{sub 2}O{sub 3}:Pd nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    Amani, Matin; Gregory, Otto J., E-mail: gregory@egr.uri.edu

    2013-09-02

    Thin film nanocomposites based on semiconducting oxides and palladium have been systematically studied using combinatorial chemistry techniques to optimize their thermoelectric properties. These nanocomposites have considerable potential for energy harvesting applications in harsh environments and were prepared by embedding palladium nanoparticles into an indium oxide matrix via co-sputtering from metal and ceramic targets. The as-deposited films were largely amorphous and thus were subsequently heat treated in nitrogen ambients to produce crystalline nanocomposites. These nanocomposite films were screened for their thermoelectric properties at room temperature as a function of composition, and the resulting films exhibited thermoelectric power factors that were significantly greater than the semiconducting oxides deposited directly from ceramic targets. Based on these rapid screening protocols employing hundreds of micro-thermocouples, the most promising nanocomposite films in terms of thermoelectric power factor were down-selected. Transmission electron microscopy, selected area electron diffraction, and scanning electron microscopy were then used to study the microstructural changes in these films as a function of temperature. When thermally cycled to 800 °C, an abrupt transition from normal, equiaxed grain growth to abnormal (spherulitic growth) was observed at a threshold palladium loading which was also optimal for thermoelectric energy harvesting. - Highlights: • Films consisting of Pd nanoparticles in an In{sub 2}O{sub 3} matrix were grown by sputtering. • These films have previously shown promising thermoelectric properties. • Transmission and scanning electron microscopy were used to investigate the films • This was determined for various compositions and annealing temperatures.

  15. Strain-induced grain growth of cryomilled nanocrystalline Al in trimodal composites during forging

    Energy Technology Data Exchange (ETDEWEB)

    Yao, B. [Advanced Materials Processing and Analysis Center, and Department of Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, FL 32816 (United States); Simkin, B.; Majumdar, B. [Materials and Metallurgical Engineering Department, New Mexico Institute of Mining and Technology, Socorro, NM 87801 (United States); Smith, C.; Bergh, M. van den [DWA Aluminum Composites, Chatsworth, CA 91311 (United States); Cho, K. [Weapons and Materials Research Directorate, U.S. Army Research Laboratory, Aberdeen Proving Ground, MD 21005 (United States); Sohn, Y.H., E-mail: Yongho.Sohn@ucf.edu [Advanced Materials Processing and Analysis Center, and Department of Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, FL 32816 (United States)

    2012-02-28

    Highlights: Black-Right-Pointing-Pointer Grain growth of cryomilled nanocrystalline aluminum during hot forging. Black-Right-Pointing-Pointer Use of hollow cone dark field imaging technique in TEM for grain size measurement. Black-Right-Pointing-Pointer Grain growth model of strain, strain rate and temperature for forging optimization. - Abstract: Grain growth of nanocrystalline aluminum ({sup nc}Al) in trimodal Al metal-matrix-composites (MMCs) during hot forging was investigated. The {sup nc}Al phase formed through cryomilling of inert gas-atomized powders in liquid nitrogen has an average grain size down to 21 nm, exhibits excellent thermal stability. However, substantial grain growth of {sup nc}Al up to 63 nm was observed when the Al MMCs were thermo-mechanically processed even at relatively low temperatures. Grain growth of the cryomilled {sup nc}Al phase in trimodal Al MMCs after hot forging was documented with respect to temperature ranging from 175 Degree-Sign C to 287 Degree-Sign C, true strain ranging from 0.4 to 1.35 and strain rate ranging from 0.1 to 0.5 s{sup -1}. Hollow cone dark field imaging technique was employed to provide statistically confident measurements of {sup nc}Al grain size that ranged from 21 to 63 nm. An increase in forging temperature and an increase in true strain were correlated with an increase in grain size of {sup nc}Al. Results were correlated to devise a phenomenological grain growth model for forging that takes strain, strain rate and temperature into consideration. Activation energy for the grain growth during thermo-mechanical hot-forging was determined to be 35 kJ/mol, approximately a quarter of activation energy for bulk diffusion of Al and a half of activation energy for static recrystallization.

  16. Modeling of Austenite Grain Growth During Austenitization in a Low Alloy Steel

    Science.gov (United States)

    Dong, Dingqian; Chen, Fei; Cui, Zhenshan

    2016-01-01

    The main purpose of this work is to develop a pragmatic model to predict austenite grain growth in a nuclear reactor pressure vessel steel. Austenite grain growth kinetics has been investigated under different heating conditions, involving heating temperature, holding time, as well as heating rate. Based on the experimental results, the mathematical model was established by regression analysis. The model predictions present a good agreement with the experimental data. Meanwhile, grain boundary precipitates and pinning effects on grain growth were studied by transmission electron microscopy. It is found that with the increasing of the temperature, the second-phase particles tend to be dissolved and the pinning effects become smaller, which results in a rapid growth of certain large grains with favorable orientation. The results from this study provide the basis for the establishment of large-sized ingot heating specification for SA508-III steel.

  17. Grain growth and thermal stability accompanying recrystallization in undercooled Ni-3at.%Sn alloy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z., E-mail: chenzheng1218@163.com [School of Material Science and Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221116 (China); State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an, Shaanxi 710016 (China); Chen, Q.; Shen, C.J. [School of Material Science and Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221116 (China); Liu, F. [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an, Shaanxi 710016 (China)

    2015-10-15

    The grain growth and thermal stability after recrystallization in as-solidified highly undercooled Ni-3at.%Sn alloy melt were investigated. As for undercooled Ni-3at.%Sn alloy, a transition from dendritic to granular crystals occurred when ΔT≥ΔT{sup *}, which was induced by the plastic deformation of dendrites and subsequent recrystallization. On this basis, the subsequent grain growth and solute segregation accompanying recalescence were calculated by a recently proposed thermo-kinetic model, which showed close agreement with the experimental results. It is concluded that the grain growth process was interrelated to recalescence, solute trapping and solute segregation of Sn atoms captured by solute trapping, which was responsible for the reduction of grain boundary energy and improvement of thermal stability. - Highlights: • A transition from dendritic to granular crystals occurred when ΔT≥ΔT{sup *}. • The grain growth accompanying recalescence was calculated. • A close agreement with the experimental results was shown.

  18. Effect of zirconium on grain growth and mechanical properties of a ball-milled nanocrystalline FeNi alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kotan, Hasan, E-mail: hkotan@ncsu.edu [Department of Materials Science and Engineering, NC State University, 911 Partners Way, Room 3078, Raleigh, NC 27606-7907 (United States); Darling, Kris A. [U.S. Army Research Laboratory, Weapons and Materials Research Directorate, RDRL-WMM-F, Aberdeen Proving Ground, MD 21005-5069 (United States); Saber, Mostafa; Koch, Carl C.; Scattergood, Ronald O. [Department of Materials Science and Engineering, NC State University, 911 Partners Way, Room 3078, Raleigh, NC 27606-7907 (United States)

    2013-02-25

    Highlights: Black-Right-Pointing-Pointer Pure Fe, Fe{sub 92}Ni{sub 8}, and Fe{sub 91}Ni{sub 8}Zr{sub 1} powders were hardened up to 10 GPa by ball milling. Black-Right-Pointing-Pointer Annealing of Fe and Fe{sub 92}Ni{sub 8} leads to reduced hardness and extensive grain growth. Black-Right-Pointing-Pointer The addition of Zr to Fe{sub 92}Ni{sub 8} increases its stability and strength by second phases. Black-Right-Pointing-Pointer The second phases are found to promote the stability of Fe{sub 91}Ni{sub 8}Zr{sub 1} by Zener pinning. Black-Right-Pointing-Pointer The Zr-containing precipitates contribute to the overall strength of the material. - Abstract: Grain growth of ball-milled pure Fe, Fe{sub 92}Ni{sub 8}, and Fe{sub 91}Ni{sub 8}Zr{sub 1} alloys has been studied using X-ray diffractometry (XRD), focused ion beam (FIB) microscopy and transmission electron microscopy (TEM). Mechanical properties with respect to compositional changes and annealing temperatures have been investigated using microhardness and shear punch tests. We found the rate of grain growth of the Fe{sub 91}Ni{sub 8}Zr{sub 1} alloy to be much less than that of pure Fe and the Fe{sub 92}Ni{sub 8} alloy at elevated temperatures. The microstructure of the ternary Fe{sub 91}Ni{sub 8}Zr{sub 1} alloy remains nanoscale up to 700 Degree-Sign C where only a few grains grow abnormally whereas annealing of pure iron and the Fe{sub 92}Ni{sub 8} alloy leads to extensive grain growth. The grain growth of the ternary alloy at high annealing temperatures is coupled with precipitation of Fe{sub 2}Zr. A fine dispersion of precipitated second phase is found to promote the microstructural stability at high annealing temperatures and to increase the hardness and ultimate shear strength of ternary Fe{sub 91}Ni{sub 8}Zr{sub 1} alloy drastically when the grain size is above nanoscale.

  19. Effect of electric current pulse on grain growth in superplastic deformation of 2091 Al-Li alloy

    Institute of Scientific and Technical Information of China (English)

    刘志义; 许晓嫦; 崔建忠

    2003-01-01

    The effect of electric current pulse on the grain growth in the superplastic deformation of 2091 Al-Li alloy was investigated. Optical metallographic microstructure observation and average linear intercept measuring results show that at same strain, the grain size in the superplastic deformation loaded with electric current pulse is smaller than that unemploying electric current pulse, and so does the grain growth rate. TEM observation shows that the dislocation density at grain boundary in the superplastic deformation applied with electric current pulse is lower than that unemploying electric current pulse.It indicates that electric current pulse increases the rate of dislocation slip and climb in grain boundary, which leads to a decrease of both the density of the dislocation slipping across grain boundary at same strain rate and the driving force for grain growth, therefore the rate of grain growth decreases.The established model for grain growth shows an exponential relation of grain size with strain.

  20. Grain growth kinetics for B2O3-doped ZnO ceramics

    Directory of Open Access Journals (Sweden)

    Yuksel Berat

    2015-06-01

    Full Text Available Grain growth kinetics in 0.1 to 2 mol % B2O3-added ZnO ceramics was studied by using a simplified phenomenological grain growth kinetics equation Gn = K0 · t · exp(-Q/RT together with the physical properties of sintered samples. The samples, prepared by conventional ceramics processing techniques, were sintered at temperatures between 1050 to 1250 °C for 1, 2, 3, 5 and 10 hours in air. The kinetic grain growth exponent value (n and the activation energy for the grain growth of the 0.1 mol % B2O3-doped ZnO ceramics were found to be 2.8 and 332 kJ/mol, respectively. By increasing B2O3 content to 1 mol %, the grain growth exponent value (n and the activation energy decreased to 2 and 238 kJ/mol, respectively. The XRD study revealed the presence of a second phase, Zn3B2O6 formed when the B2O3 content was > 1 mol %. The formation of Zn3B2O6 phase gave rise to an increase of the grain growth kinetic exponent and the grain growth activation energy. The kinetic grain growth exponent value (n and the activation energy for the grain growth of the 2 mol % B2O3-doped ZnO ceramics were found to be 3 and 307 kJ/mol, respectively. This can be attributed to the second particle drag (pinning mechanism in the liquid phase sintering.

  1. Annealing twin development during recrystallization and grain growth in pure nickel

    OpenAIRE

    Jin, Yuan; Lin, Brian; Bernacki, Marc; Gregory S. Rohrer; Rollet, Anthony D.; Bozzolo, Nathalie

    2014-01-01

    International audience A 99.995% pure Ni sample, compressed to 25%, was annealed in a SEM chamber and changes in the density of annealing twins were monitored in situ during recrystallization and grain growth. In addition to average microstructural measurements, the evolution of individual grains was also observed. Both the average annealing twin density in the recrystallized domain and the annealing twin density per grain increased during recrystallization. The rate of increase in twin de...

  2. Austenite Grain Growth and the Surface Quality of Continuously Cast Steel

    Science.gov (United States)

    Dippenaar, Rian; Bernhard, Christian; Schider, Siegfried; Wieser, Gerhard

    2014-04-01

    Austenite grain growth does not only play an important role in determining the mechanical properties of steel, but certain surface defects encountered in the continuous casting industry have also been attributed to the formation of large austenite grains. Earlier research has seen innovative experimentation, the development of metallographic techniques to determine austenite grain size and the building of mathematical models to simulate the conditions pertaining to austenite grain growth during the continuous casting of steel. Oscillation marks and depressions in the meniscus region of the continuously casting mold lead to retarded cooling of the strand surface, which in turn results in the formation of coarse austenite grains, but little is known about the mechanism and rate of formation of these large austenite grains. Relevant earlier research will be briefly reviewed to put into context our recent in situ observations of the delta-ferrite to austenite phase transition. We have confirmed earlier evidence that very large delta-ferrite grains are formed very quickly in the single-phase region and that these large delta-ferrite grains are transformed to large austenite grains at low cooling rates. At the higher cooling rates relevant to the early stages of the solidification of steel in a continuously cast mold, delta-ferrite transforms to austenite by an apparently massive type of transformation mechanism. Large austenite grains then form very quickly from this massive type of microstructure and on further cooling, austenite transforms to thin ferrite allotriomorphs on austenite grain boundaries, followed by Widmanstätten plate growth, with almost no regard to the cooling rate. This observation is important because it is now well established that the presence of a thin ferrite film on austenite grain boundaries is the main cause of reduction in hot ductility. Moreover, this reduction in ductility is exacerbated by the presence of large austenite grains.

  3. Grain growth in four dimensions: A comparison between simulation and experiment

    DEFF Research Database (Denmark)

    McKenna, I.M.; Poulsen, S.O.; Lauridsen, Erik Mejdal;

    2014-01-01

    A 3-D isotropic phase field simulation was used to predict the morphology of individual grains during grain growth. The simulation employed a polycrystalline array of titanium alloy Ti-β-21S experimentally characterized by X-ray tomography as an initial condition. The non-destructive nature of X...

  4. Grain growth kinetics of textured-BaTiO3 ceramics

    Indian Academy of Sciences (India)

    Fang Fu; Jiwei Zhai; Zhengkui Xu; Bo Shen; Xi Yao

    2014-06-01

    Textured BaTiO3 (BT) ceramics were fabricated by templated grain growth method. Effects of sintering conditions on the grain growth process of textured-BT ceramics were investigated. Orientation degree increased initially and then decreased with increasing soaking time. The ceramics were composed of equiaxed matrix grains and brick-like template particles. The brick-like particles aligned parallel to the casting direction by observing from SEM images. A (ℎ00)-preferred orientation was confirmed by SAED and XRD patterns. Mechanism of grain growth in textured-BT ceramics was studied. Both consumption of matrix by templates and grain growth of templates determined the orientation degree of ceramics. The kinetic mechanism for grain orientation was also discussed by the simplified phenomenological kinetic equation. The average activation energies were 364 kJ/mol for matrix grain and 918 kJ/mol for template particle, respectively. Finally, a dense ceramic with 85% grain orientation was obtained after sintering at 1400°C for 2 h.

  5. In situ observation of austenite grain growth behavior in the simulated coarse-grained heat-affected zone of Ti-microalloyed steels

    Institute of Scientific and Technical Information of China (English)

    Xiang-liang Wan; Kai-ming Wu; Gang Huang; Ran Wei; Lin Cheng

    2014-01-01

    The austenite grain growth behavior in a simulated coarse-grained heat-affected zone during thermal cycling was investigated via in situ observation. Austenite grains nucleated at ferrite grain boundaries and then grew in different directions through movement of grain boundaries into the ferrite phase. Subsequently, the adjacent austenite grains impinged against each other during theα→γtransformation. After theα→γtransformation, austenite grains coarsened via the coalescence of small grains and via boundary migration between grains. The growth process of austenite grains was a continuous process during heating, isothermal holding, and cooling in simulated thermal cy-cling. Abundant finely dispersed nanoscale TiN particles in a steel specimen containing 0.012wt%Ti effectively retarded the grain boundary migration, which resulted in refined austenite grains. When the Ti concentration in the steel was increased, the number of TiN particles de-creased and their size coarsened. The big particles were not effective in pinning the austenite grain boundary movement and resulted in coarse austenite grains.

  6. Abnormal mandibular growth after craniovertebral surgery in Morquio syndrome type A.

    Science.gov (United States)

    Defraia, Efisio; Marinelli, Andrea; Antonini, Antonino; Giuntini, Veronica

    2005-05-01

    Morquio syndrome or MPS4A is an autosomal recessive inherited metabolic disease, due to a deficiency of N-acetil-galactosamine-6-sulfatase (OMIM 253000). Hypoplastic odontoid processes causing atlantoaxial subluxation and cervical myelopathy are usual clinical findings. Surgical intervention of craniocervical fusion is often performed to prevent this complication. Clinical and cephalometric findings in a patient affected by Morquio syndrome after craniovertebral surgery are described. Facial growth pattern in the lateral plane changed dramatically. The mandibular gonial angle (ArGoMe), the body of the mandible (GoGn), and the total length of the mandible (CoGn) increased abnormally, whereas the mandibular ramus (CoGo) exhibited normal growth. Knowledge of the possibility of abnormal mandibular growth may contribute in long-term orthodontic management of such subjects. PMID:15898389

  7. Growth Abnormalities in Children with Type 1 Diabetes, Juvenile Chronic Arthritis, and Asthma

    Directory of Open Access Journals (Sweden)

    Cosimo Giannini

    2014-01-01

    Full Text Available Children and adolescents with chronic diseases are commonly affected by a variable degree of growth failure, leading to an impaired final height. Of note, the peculiar onset during childhood and adolescence of some chronic diseases, such as type 1 diabetes, juvenile idiopathic arthritis, and asthma, underlines the relevant role of healthcare planners and providers in detecting and preventing growth abnormalities in these high risk populations. In this review article, the most relevant common and disease-specific mechanisms by which these major chronic diseases affect growth in youth are analyzed. In addition, the available and potential targeting strategies to restore the physiological, hormonal, and inflammatory pattern are described.

  8. Recrystallization and Grain Growth in Austenitic Stainless Steels: a Statistical Approach

    Institute of Scientific and Technical Information of China (English)

    A.Di Schino; G.Abbruzzese; J.M. Kenny

    2003-01-01

    A mathematical model, able to describe the recrystallization and grain growth in metals, has been developed. Taking into account the classical constitutive equations of the Taylor′s theory, the model involves only two free parameters (the dislocation den

  9. MODELING OF FERRITE GRAIN GROWTH OF LOW CARBON STEELS DURING HOT ROLLING

    Institute of Scientific and Technical Information of China (English)

    Y.T. Zhang; D.Z. Li; Y.Y. Li

    2002-01-01

    For most commercial steels the prediction of the final properties depends on accuratelycalculating the room temperature ferrite grain size. A grain growth model is proposedfor low carbon steels Q235B during hot rolling. By using this model, the initial ferritegrain size after continuous cooling and ferrite grain growing in coiling procedure canbe predicted. Finally, in-plant trials were performed in the hot strip mill of Ansteel.The calculated final ferrite grain sizes are in good agreement with the experimentalones. It is helpful both for simulation of microstructure evolution and prediction ofmechanical properties.

  10. Bounding box framework for efficient phase field simulation of grain growth in anisotropic systems

    CERN Document Server

    Vanherpe, L; Blanpain, B; Vandewalle, S

    2011-01-01

    A sparse bounding box algorithm is extended to perform efficient phase field simulations of grain growth in anisotropic systems. The extended bounding box framework allows to attribute different properties to different grain boundary types of a polycrystalline microstructure and can be combined with explicit, implicit or semi-implicit time stepping strategies. To illustrate the applicability of the software, the simulation results of a case study are analysed. They indicate the impact of a misorientation dependent boundary energy formulation on the evolution of the misorientation distribution of the grain boundary types and on the individual growth rates of the grains as a function of the number of grain faces. (C) 2011 Elsevier B.V. All rights reserved.

  11. Dynamic Recrystallization and Grain Growth Behavior of 20SiMn Low Carbon Alloy Steel

    Institute of Scientific and Technical Information of China (English)

    DONG Lanfeng; ZHONG Yuexian; MA Qingxian; YUAN Chaolong; MA Lishen

    2008-01-01

    A senes of thermodynamics experiments were used to optimize the hot forging process of 20SiMn low-carbon alloy steel.A dynamic recrystallization and grain growth model was developed for the 20SiMn steel for common production conditions of heavy forgings by doing a nonlinear curve fit of the expenment data.Optimized forging parameters were developed based on the control of the dynamic recrystallization and the MnS secondary phase.The data shows that the initial grain size and the MnS secondary phase all affect the behavior of the 20SiMn dynamic recrystallization and grain growth.

  12. Growth competition of columnar dendritic grains: A phase-field study

    International Nuclear Information System (INIS)

    We report the results of an extensive phase-field study of the growth competition of columnar dendritic grains in two dimensions. We investigate the influence of the temperature gradient and grain bicrystallography on the selection of both grain and microstructure, focusing on a geometry with two grains with principal crystal axes oriented parallel and at a finite misorientation angle with respect to the axis of the temperature gradient. Our first main finding is that, for well-developed dendritic structures forming at a low-temperature gradient, the rate of elimination of the misoriented grain is a non-monotonic function of the difference in undercooling between the dendrite tips of the two grains. Hence this rate cannot be predicted even qualitatively by the common assumption that the elimination rate increases with this undercooling difference. The breakdown of this assumption is particularly striking for highly misoriented dendritic and degenerate structures that persist for very long times despite growing at a substantially larger undercooling than the well-oriented neighboring grains. Our second main finding is that microscopic thermal fluctuations at the origin of sidebranching can induce significant variations in the macroscopic trajectories of grain boundaries (GBs), thereby making grain selection a stochastic process, while yielding limited variations in the selected primary spacings. In contrast, in the absence of fluctuations, GB motion becomes essentially deterministic and grain elimination is suppressed. In addition, our simulations reproduce quantitatively scaling laws deduced from experiments for both the primary dendritic spacing and the dendrite growth direction of misoriented grains. They further reveal that the “intergrain” primary spacing selected by tertiary branching events at GBs is systematically larger than the “intragrain” primary spacing selected by the transient growth competition between primary branches within a single grain

  13. Combining cellular automata and Monte Carlo algorithm to simulate three-dimensional grain growth

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; CHEN Ju-hua; GUO Pei-quan; ZHAO Ping

    2006-01-01

    A 3-D simulation of grain growth was conducted by utilizing cellular automata (CA) and Monte Carlo (MC) algorithm. In the simulating procedure, the three-dimensional space is divided into a large number of 2-D isometric planes. Then, each of the planes is divided into identical square cells. Finally, the cellular automata and Monte Carlo algorithm are combined together to simulate the grain growth. Through an evolutionary simulation, the recrystallized microstructure, the grain growth rate and the grain size distribution are acceptably predicted. The simulation routine can be used to simulate the real physical-metallurgy processes and to predict quantitative dynamic information of the evolution of microstructure. Further more, the method is also useful for optimization of materials properties by controlling the microstructure evolution.

  14. In situ measurements of growth rates and grain-averaged activation energies of individual grains during recrystallization of 50% cold-rolled aluminium

    International Nuclear Information System (INIS)

    Research highlights: → We study recrystallization kinetics - and activation energies of individual grains. → The kinetics is found to deviate significantly from mean kinetics. → An explanation for the observed kinetics is proposed. → Activation energies of individual grains are found to form a broad distribution. -- Three-dimensional X-ray diffraction has been used to study the growth kinetics of 1406 individual grains recrystallizing in 50% cold-rolled aluminium. It is found that each grain follows its own kinetics. The radial growth of individual grains is found to often be piecewise linear, and an explanation based on the cell block microstructure of cold-rolled aluminium is proposed. Grain-averaged activation energies of 793 individual grains are determined, and found to constitute a broad distribution. Reasons and implications of these findings are discussed.

  15. Abnormal Doppler flow velocimetry in the growth restricted foetus as a predictor for necrotising enterocolitis.

    OpenAIRE

    Bhatt A; Tank P; Barmade K; Damania K

    2002-01-01

    BACKGROUND: Obstetric decision- making for the growth restricted foetus has to take into consideration the benefits and risks of waiting for pulmonary maturity and continued exposure to hostile intra-uterine environment. Necrotising Enterocolitis (NEC) results from continued exposure to hostile environment and is an important cause of poor neonatal outcome. AIMS: To evaluate the predictive value of abnormal Doppler flow velocimetry of the foetal umbilical artery for NEC and neonatal mortality...

  16. Electrical Properties and Grain Growth Kinetics of PZN-based Ceramics Using Microwave Sintering

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Effectiveness of microwave sintering process through investigation of microstructural characteristics and electrical properties of x(0.94PbZn1/3 Nb2/3O3 + 0.06BaTiO3) + (1 - x)PbZryTi1-yO3 (PBZNZT) ceramics with x = 0.6 and y = 0.52 was evaluated. The relative density of 95% was achieved with sintering at 800℃ for 2 h. The small grain growth exponents indicate how easy the grain growth in these materials sintered using microwave radiation. Grain growth rate increases abruptly and is higher than that of conventional sintering at a temperature higher than 1050℃. This is attributed to the lower activation energy and higher grain boundary mobility. The activation energy required for the grain growth is found to be 132kJ/mol. Higher remanent polarization (Pr = 50.1μC/cm2) and increase in remanent polarization with sintering temperature are observed in microwave sintering process when compared to that of conventional sintering process,due to fast increase in grain growth rate and homogeneity in the specimen. The results indicate lower sintering energy and reduction of PbO pollution in the working environment by microwave sintering process.

  17. The effect of maternal exercise during pregnancy on abnormal fetal growth

    OpenAIRE

    Tomić, Vlatka; Sporiš, Goran; Tomić, Jozo; Milanović, Zoran; Zigmundovac-Klaić, Djurdja; Pantelić, Saša

    2013-01-01

    Aim To assess the effect of maternal physical activity during pregnancy on abnormal fetal growth. Methods The study group of 166 women in gestational week 6-8 exercised regularly three days per week at submaximal intensity during their entire pregnancy and the control group of 168 women received standard antenatal care. The main outcomes were macrosomia and intrauterine growth restriction. Results The study group had a lower frequency of macrosomia in newborns (6.0% vs 12.5%, P = 0.048) and g...

  18. Grain growth of Ni-based superalloy IN718 coating fabricated by pulsed laser deposition

    Science.gov (United States)

    Zhang, Yaocheng; Yang, Li; Dai, Jun; Huang, Zedong; Meng, Tao

    2016-06-01

    The pulsed laser deposited Ni-based superalloy coating was fabricated with successive 12 layers using single tracks. The microstructure of the deposited coating was observed by scanning electron microscopy (SEM). The grain growth and the grain boundary misorientation were investigated by electron backscatter diffraction (EBSD), the precipitation phase was determined by transmission electron microscope (TEM). The results showed that the dendrites were the most common microstructure in the coating, and the dendritic growth orientation was paralleled to the direction of the laser deposition. The dendrite got coarser and its space was increased with increasing laser deposited layers. Most grains grew along the preferential grain orientation and formed anisotropy with grain boundaries misorientation angle about 2° in the pulsed laser deposited coating. The grain size along the texture orientation was 3-10 times larger than that in the transverse orientation. The cross section microhardness of the coating ranged between 240-280 HV, and decreased along the depositional direction due to the reasons of the variation of eutectic morphology, grain size distribution, grain misorientation and a small amounts of strengthening phase precipitation.

  19. Maternal risk factors for abnormal placental growth: The national collaborative perinatal project

    Directory of Open Access Journals (Sweden)

    Nicholson Wanda K

    2008-09-01

    Full Text Available Abstract Background Previous studies of maternal risk factors for abnormal placental growth have focused on placental weight and placental ratio as measures of placental growth. We sought to identify maternal risk factors for placental weight and two neglected dimensions of placental growth: placental thickness and chorionic plate area. Methods We conducted an analysis of 24,135 mother-placenta pairs enrolled in the National Collaborative Perinatal Project, a prospective cohort study of pregnancy and child health. We defined growth restriction as th percentile and hypertrophy as > 90th percentile for three placental growth dimensions: placental weight, placental thickness and chorionic plate area. We constructed parallel multinomial logistic regression analyses to identify (a predictors of restricted growth (vs. normal and (b predictors of hypertrophic growth (vs. normal. Results Black race was associated with an increased likelihood of growth restriction for placental weight, thickness and chorionic plate area, but was associated with a reduced likelihood of hypertrophy for these three placental growth dimensions. We observed an increased likelihood of growth restriction for placental weight and chorionic plate area among mothers with hypertensive disease at 24 weeks or beyond. Anemia was associated with a reduced likelihood of growth restriction for placental weight and chorionic plate area. Pre-pregnancy BMI and pregnancy weight gain were associated with a reduced likelihood of growth restriction and an increased likelihood of hypertrophy for all three dimensions of placental growth. Conclusion Maternal risk factors are either associated with placental growth restriction or placental hypertrophy not both. Our findings suggest that the placenta may have compensatory responses to certain maternal risk factors suggesting different underlying biological mechanisms.

  20. EFFECT OF SOME PLANT GROWTH REGULATORS WITH RETARDING ACTIVITY ON SPRING PEA FOR GRAIN

    Directory of Open Access Journals (Sweden)

    Tsenka ZHELYAZKOVA

    2012-12-01

    Full Text Available A field experiment was conducted at Trakia University - Stara Zagora to establish the effect of some growth retardants on morphological and productive parameters in spring pea for grain variety Bogatir. Three combined preparations: Trisalvit (phenylphthalamic acid + chlorocholine chloride + chlorophenoxyacetic acid +salicylic acid at doses of 300 and 400 сmз*ha-1; SM-21 (phenylphthalamic acid + chlorocholine chloride at doses of 300 and 400 сmз*ha-1 and PNSA-44 (phenylphthalamic acid + naphthaleneacetic acid + chlorophenoxyacetic acid at doses of 200 and 300 сmз*ha-1 were applied in the early growth phase of the plant up to a height of 15-20 cm. The study showed that the greatest reduction in the stem height (by 12.8% compared to untreated plants was achieved by applying SM-21 (400 сmз*ha-1. The application of growth regulators Trisalvit and SM-21 had no appreciable effect on the production of spring pea grain. Maximum values of yield structure components (number of pods and grain per plant, grain mass per plant and mass of 1000 grain and the yield were obtained after application of PNSA-44 (300 сmз*ha-1 - up to 5.6% (117.2 kg*ha-1 more grain than the control. The investigation of the influence of tested factors (retardant, dose and year demonstrated that the conditions of the year as a factor had the strongest effect on plant height and grain yield.

  1. Predicting the Probability of Abnormal Stimulated Growth Hormone Response in Children After Radiotherapy for Brain Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Hua Chiaho, E-mail: Chia-Ho.Hua@stjude.org [Department of Radiological Sciences, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Wu Shengjie [Department of Biostatistics, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Chemaitilly, Wassim [Division of Endocrinology, Department of Pediatric Medicine, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Lukose, Renin C.; Merchant, Thomas E. [Department of Radiological Sciences, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States)

    2012-11-15

    Purpose: To develop a mathematical model utilizing more readily available measures than stimulation tests that identifies brain tumor survivors with high likelihood of abnormal growth hormone secretion after radiotherapy (RT), to avoid late recognition and a consequent delay in growth hormone replacement therapy. Methods and Materials: We analyzed 191 prospectively collected post-RT evaluations of peak growth hormone level (arginine tolerance/levodopa stimulation test), serum insulin-like growth factor 1 (IGF-1), IGF-binding protein 3, height, weight, growth velocity, and body mass index in 106 children and adolescents treated for ependymoma (n = 72), low-grade glioma (n = 28) or craniopharyngioma (n = 6), who had normal growth hormone levels before RT. Normal level in this study was defined as the peak growth hormone response to the stimulation test {>=}7 ng/mL. Results: Independent predictor variables identified by multivariate logistic regression with high statistical significance (p < 0.0001) included IGF-1 z score, weight z score, and hypothalamic dose. The developed predictive model demonstrated a strong discriminatory power with an area under the receiver operating characteristic curve of 0.883. At a potential cutoff point of probability of 0.3 the sensitivity was 80% and specificity 78%. Conclusions: Without unpleasant and expensive frequent stimulation tests, our model provides a quantitative approach to closely follow the growth hormone secretory capacity of brain tumor survivors. It allows identification of high-risk children for subsequent confirmatory tests and in-depth workup for diagnosis of growth hormone deficiency.

  2. Abnormal Doppler flow velocimetry in the growth restricted foetus as a predictor for necrotising enterocolitis.

    Directory of Open Access Journals (Sweden)

    Bhatt A

    2002-07-01

    Full Text Available BACKGROUND: Obstetric decision- making for the growth restricted foetus has to take into consideration the benefits and risks of waiting for pulmonary maturity and continued exposure to hostile intra-uterine environment. Necrotising Enterocolitis (NEC results from continued exposure to hostile environment and is an important cause of poor neonatal outcome. AIMS: To evaluate the predictive value of abnormal Doppler flow velocimetry of the foetal umbilical artery for NEC and neonatal mortality. SETTINGS AND DESIGN: A retrospective study carried out at a tertiary care centre for obstetric and neonatal care. MATERIALS AND METHOD: Seventy-seven neonates with birth weight less than 2000 gm, born over a period of 18 months were studied. These pregnancies were identified as having growth abnormalities of the foetus. Besides other tests of foetal well-being, they were also subjected to Doppler flow velocimetry of the foeto-placental vasculature. Obstetric outcome was evaluated with reference to period of gestation and route of delivery. The neonatal outcome was reviewed with reference to birth weight, Apgar scores and evidence of NEC. STATISTICAL ANALYSIS USED: Chi square test. RESULTS: In the group of patients with Absent or Reverse End Diastolic Frequencies (A/R EDF in the umbilical arteries, positive predictive value for NEC was 52.6%, (RR 30.2; OR 264. The mortality from NEC was 50%. When umbilical artery velocimetry did not show A/REDF, there were no cases of NEC or mortality. Abnormal umbilical or uterine artery flow increased the rate of caesarean section to 62.5% as compared to 17.6% in cases where umbilical artery flow was normal. CONCLUSION: In antenatally identified pregnancies at risk for foetal growth restriction, abnormal Doppler velocimetry in the form of A/REDF in the umbilical arteries is a useful guide to predict NEC and mortality in the early neonatal period.

  3. Grain growth studies of silicon nitride dispersed in an oxynitride glass

    International Nuclear Information System (INIS)

    Isothermal growth of β-Si3N4 crystals dispersed in an oxynitride glass (Y-Si-Al-O-N) was studied by electron microscopy after heat treatment at temperatures between 1,550 and 1,640 C for 1 to 18 h. The β-crystals exhibited growth striations introduced by intermediate coolings and these striations were used for developing a sophisticated technique for analysis of growth. It was determined that α/β-transformation and Ostwald ripening can be treated as different kinetic stages of grain growth, while β-nucleation was found to be insignificant. The mean diameter of the needle like β-grains was almost constant during phase transformation, indicating negligible growth of the β-prism plane; growth was mainly one-dimensional with the maximum mean length and aspect ratio just at the end of the phase transformation. The growth rate of the β-basal plane was independent of diameter, indicating interface-controlled growth. During Ostwald ripening, the length distribution broadened and the aspect ratio of smaller grains decreased. Dissolution of small grains caused an increase in the mean diameter, while the mean aspect ratio decreased

  4. Analysis of the growth of individual grains during recrystallization in pure nickel

    DEFF Research Database (Denmark)

    Zhang, Y.B.; Godfrey, A.; Liu, Q.;

    2009-01-01

    The growth of individual grains during recrystallization in 96% cold-rolled pure nickel has been followed using electron backscatter pattern maps of the same surface area taken after each of several annealing steps. It was found that the growth is quite complex, with boundaries moving, stopping...

  5. Studies of methods to restrict the grain growth of nanocrystalline metal oxides

    CERN Document Server

    Al-Angari, Y

    2002-01-01

    There is considerable interest in nanocrystalline materials. This thesis is concerned with nanocrystalline oxides and the development of methods to prevent their grain growth on heating. This growth, which is evident at temperatures as low as 400 deg C, presents a serious problem in the study and applications of nanocrystalline oxides. The systems that were studied were nanocrystalline magnesium oxide, zirconium oxide, cerium oxide and tin oxide. The methods of preventing grain growth included the encapsulation of the oxide in the pores of porous silica, mixing with nanocrystals of alumina and treating the surface with a silanising agent, hexamethyldisilazane. All the methods employed showed some effect on reducing the grain growth. Encapsulation in the pores of silica was effective, however it proved difficult to get large amounts of the oxides into the pores. A more efficient method of preparing large samples was the incorporation of alumina, which was achieved by a sol-gel process. An alkoxide of the targe...

  6. Texture development of Ni{sub 3}Al thin foils during recrystallization and grain growth

    Energy Technology Data Exchange (ETDEWEB)

    Demura, M.; Kishida, K.; Xu, Y.; Hirano, T. [Materials Engineering Lab., National Inst. for Materials Science, Tsukuba, Ibaraki (Japan)

    2004-07-01

    The texture evolution of 83% cold-rolled Ni{sub 3}Al foils during recrystallization was examined through heat treatments at 600 C, 800 C, and 1000 C for 30 min. X-ray texture measurements revealed that the texture changed from the as-rolled Goss to a transitional complicated one by primary recrystallization and eventually returned to the Goss texture during grain growth. The SEM-EBSD analysis revealed that the return to the Goss texture was accompanied by the decrease of random boundaries (RBs) and the increase of {sigma}1 boundaries. The preferential growth of the Goss-oriented grains was explained by the difference in the grain boundary energy between the RBs and {sigma}1, based on the observed grain-orientation maps. (orig.)

  7. Inhibition effect of phosphate on the crystal grain growth of nanosized titania

    Institute of Scientific and Technical Information of China (English)

    FENG Xiaohui; LIE Jingze; LI Ping; ZHANG Yanfeng; WEI Yu

    2009-01-01

    The inhibitory effect of phosphate on the crystal grain growth of nanosized titania during high temperature calcination was investigated. Nanosized titanium dioxide powders prepared by hydrolysis of titanium tetrachloride were soaked in phosphate solutions with different con-centrations. The obtained powders calcined at various temperatures were characterized by X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), and X-ray photoelectronic spectroscopy (XPS). The grain size of the samples without phosphate treatment in-creased quickly when calcined at high temperatures, while the grain size of the samples with phosphate modification increased slowly when calcined at the same temperature. This phenomenon implies that phosphate treatment plays an important role in inhibiting the crystal grain growth of titania. The possible mechanism of the inhibition effect of phosphate on titania is discussed.

  8. Multiseeding with (100)/(100) Grain Junctions in Top Seeded Melt Growth Processed YBCO Superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, C.J.; Gee, Y.A.; Hong, G.W. [Korea Atomic Energy Research Institute, Taejon (Korea); Kim, H.J.; Joo, J.H. [Sungkyunkwan University, Suwon (Korea); Han, S.C.; Han, Y.H.; Sung, T.H.; Kim, S.J. [Korea Electric Power Research Institute, Taejon (Korea)

    2000-06-01

    Multiseeding with (100)/(100) grain junctions of top-seeded melt growth (TSMG) processed YBCO superconductors was studied. Multiple seeding shortened the processing time for the fabrication of TSMG-processed YBCO superconductors. The relationship among the number of seeds, the levitation forces and the trapped magnetic fields of the TSMG-processed YBCO samples is reported. The characteristic of the (100)/(100) grain junction is discussed in terms of a wetting angle of a melt. (author). 25 refs., 7 figs.

  9. Modelling of Grain Growth Kinetics in Porous Ceramic Materials under Normal and Irradiation Conditions

    Directory of Open Access Journals (Sweden)

    Mikhail S. Veshchunov

    2009-09-01

    Full Text Available Effect of porosity on grain growth is both the most frequent and technologically important situation encountered in ceramic materials. Generally this effect occurs during sintering, however, for nuclear fuels it also becomes very important under reactor irradiation conditions. In these cases pores and gas bubbles attached to the grain boundaries migrate along with the boundaries, in some circumstances giving a boundary migration controlled by the movement, coalescence and/or sintering of these particles. New mechanisms of intergranular bubble and pore migration which control the mobility of the grain boundary under normal and irradiation conditions are reviewed in this paper.

  10. Computer simulation of grain growth and Ostwald ripening in alumina-zirconia two-phase composites

    International Nuclear Information System (INIS)

    The kinetics of grain growth and Ostwald ripening in Al2O3-ZrO2 two-phase composites was systematically investigated using two-dimensional (2-D) computer simulations, based on a diffuse-interface field model. Using average values for the experimentally measured ratios of the grain boundary energies to the interphase boundary energy as the input, the predicted 2-D microstructural features and their evolution are in excellent qualitative agreement with experimental observations on 2-D cross sections of 3-D Al2O3-ZrO2 two-phase composite microstructures. It was found that the coupled grain growth in Al2O3-ZrO2 composites is controlled by long-range diffusion and the average size (Rt) as a function of time (t) follows the power-growth law, Rtm - R0m = kt with m = 3, which is independent of the initial microstructures and volume fractions of the two phases. The predicted variation of the kinetic coefficient (k) on the volume fraction follows a trend similar to that experimentally measured through the entire range of volume fractions. The scaling of grain size distributions is observed at a given volume fraction, i.e., they are time-invariant in the steady state. However, the characteristics of size distributions vary with the initial microstructures and the volume fractions. The relationship between matrix grain size and second-phase grain size is discussed

  11. Isothermal grain growth of reactive spray formed 7075 alloys in semi-solid state

    Institute of Scientific and Technical Information of China (English)

    Huimin Liu; Hua Cui; Bin Yang; Jishan Zhang

    2004-01-01

    The grain growth behavior in reactive spray formed 7075+2.91vol%TiC Al alloy was studied and compared with that of spray formed 7075 Al alloy at semi-solid state. The effects of in-situ TiC particles on the microstructure of spray formed 7075 Al alloy were also investigated. The specimens were heat-treated isothermally at various temperatures between the solidus and liquidus of 7075 Al alloy for times in the range of 10-60 min, then quenched in water. The microstructure of reheated specimens was characterized using scanning electron microscopy and optical microscopy. The grain size was measured using a mean linear intercept method.Results show that the in-situ TiC particles can effectively retard grain growth and refine the grain at a limited size. The grain growth exponent in Arrhenius equation increases from 2 to 3, which indicates that the in-situ TiC particles have the significant pinning effect on grain coarsening in the semi-solid state.

  12. Austenite grain growth and microstructure control in simulated heat affected zones of microalloyed HSLA steel

    International Nuclear Information System (INIS)

    The roles of microalloying niobium, titanium and vanadium for controlling austenite grain growth, microstructure evolution and hardness were investigated at different simulated heat affected zones (HAZ) for high strength low alloy (HSLA) S690QL steel. High resolution FEG-SEM has been used to characterize fine bainitic ferrite, martensite and nanosized second phases at simulated coarse and fine grain HAZs. It was found that for Ti bearing steel (Ti/N ratio is 2) austenite grain had the slowest growth rate due to the presence of most stable TiN. The fine cuboidal particles promoted intragranular acicular ferrite (IGF) formation. Nb bearing steel exhibited relatively weaker grain growth retardation compared with titanium bearing steels and a mixed microstructure of bainite and martensite was present for all simulated HAZs. IGF existed at coarse grain HAZ of Ti+V bearing steel but it was totally replaced by bainite at fine grain HAZs. Hardness result was closely related to the morphology of bainitic ferrite, intragranular ferrite and second phases within ferrite. The microstructure and hardness results of different simulated HAZs were in good agreement with welded experimental results

  13. Austenite grain growth and microstructure control in simulated heat affected zones of microalloyed HSLA steel

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lei [Department of Machine Tools and Factory Management, Technical University of Berlin, Pascalstraße 8 – 9, 10587, Berlin (Germany); Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205, Berlin (Germany); Kannengiesser, Thomas [Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205, Berlin (Germany); Institute of Materials and Joining Technology, Otto von Guericke University Magdeburg, Universitetsplatz 2, 39106, Magdeburg (Germany)

    2014-09-08

    The roles of microalloying niobium, titanium and vanadium for controlling austenite grain growth, microstructure evolution and hardness were investigated at different simulated heat affected zones (HAZ) for high strength low alloy (HSLA) S690QL steel. High resolution FEG-SEM has been used to characterize fine bainitic ferrite, martensite and nanosized second phases at simulated coarse and fine grain HAZs. It was found that for Ti bearing steel (Ti/N ratio is 2) austenite grain had the slowest growth rate due to the presence of most stable TiN. The fine cuboidal particles promoted intragranular acicular ferrite (IGF) formation. Nb bearing steel exhibited relatively weaker grain growth retardation compared with titanium bearing steels and a mixed microstructure of bainite and martensite was present for all simulated HAZs. IGF existed at coarse grain HAZ of Ti+V bearing steel but it was totally replaced by bainite at fine grain HAZs. Hardness result was closely related to the morphology of bainitic ferrite, intragranular ferrite and second phases within ferrite. The microstructure and hardness results of different simulated HAZs were in good agreement with welded experimental results.

  14. Grain Growth and Bubble Evolution in U-Mo Alloy by Multiscale Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Mei, Zhi-Gang; Liang, Linyun; Kim, Yeon Soo; Wiencek, Tom; Hofman, Gerard; Anitescu, Mihai; Yacout, Abdellatif M.

    2015-01-01

    Increased grain size in U-Mo dispersion fuel is believed to affect the fuel swelling at high fission density. In this work, a multiscale simulation approach combining first-principles calculation and phase-field modeling is used to investigate the grain growth behavior in U-Mo alloys. The material properties of U-Mo alloys predicted by first-principles calculations are incorporated into the mesoscale phase-field models to study the effect of annealing temperature, annealing time and the initial grain structures of fuel particles on the grain growth. The grain growth rate is evaluated and compared with experiment. Meanwhile, the gas bubble evolution kinetics in irradiated U-Mo alloy fuels is investigated to understand its effect on fuel swelling. We systematically examine the effect of Xe, vacancy, and SIA concentration, fission defect generation, and elastic interaction on the growth kinetics of gas bubble. The bubble size distribution and swelling of U-Mo are simulated and compared to experimental measurements.

  15. Influence of Different Growth Conditions on the Kefir Grains Production, used in the Kefiran Synthesis

    Directory of Open Access Journals (Sweden)

    Carmen Rodica Pop

    2014-11-01

    Full Text Available The purpose of this study was to optimize the kefir grains biomass production, using milk as culture media. The kefir grains were cultured at different changed conditions (temperature, time, shaker rotating speed, culture media supplemented to evaluate their effects. Results showed that optimal culture conditions were using the organic skim milk, incubated at 25°C for 24 hours with a rotation rate of 125 rpm. According to results, the growth rate was 38.9 g/L for 24 h, at 25°C using the organic milk - OSM, 36.87 g/L during 24 hours, optimal time for propagation process gave 37.93 g/L kefir grains biomass when the effect of temperature level was tested. The homogenization of medium with shaker rotating induced a greater growth rate, it was obtained 38.9 g/L for 24 h, at 25°C using rotation rate at 125 rpm. The growing medium (conventional milk supplemented with different minerals and vitamins may lead to improve the growth conditions of kefir grains biomass. The optimization of the growth environment is very important for achieving the maximum production of kefir grains biomass, substrate necessary to obtain the polysaccharide kefiran

  16. Synchrotron characterization of nanograined UO2 grain growth

    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.

  17. Grain Growth Kinetics of BaTiO3 Nanocrystals During Calcining Process

    Science.gov (United States)

    Song, Xiao-lan; He, Xi; Yang, Hai-ping; Qu, Yi-xin; Qiu, Guan-zhou

    2008-06-01

    BaTiO3 nanocrystals were synthesized by sol-gel method using barium acetate (Ba(CH3COO)2) and tetra-butyl titanate (Ti(OC4H9)4) as raw materials. Xerogel precursors and products were characterized by means of thermogravimetric/differential scanning calorimetry (TG/DSC), X-ray diffraction (XRD) and transmission electron microscope (TEM). The influence of the calcination temperature and duration on the lattice constant, the lattice distortion, and the grain size of BaTiO3 nanocrystals was discussed based on the XRD results. The grain growth kinetics of BaTiO3 nanocrystals during the calcination process were simulated with a conventional grain growth model which only takes into account diffusion, and an isothermal model proposed by Qu and Song, which takes into account both diffusion and surface reactions. Using these models, the pre-exponential factor and the activation energy of the rate constant were estimated. The simulation results indicate that the isothermal model is superior to the conventional one in describing the grain growth process, implying that both diffusion and surface reactions play important roles in the grain growth process.

  18. An experimental study of grain growth in mixed oxide samples with various microstructures and plutonium concentrations

    International Nuclear Information System (INIS)

    Samples of (U, Pu)O2 Mixed Oxide (MOX) with various microstructure and plutonium contents ranging between 4% and 25% have been submitted to a series of heat treatments in order to assess grain growth between 1350 and 1750 °C. XRD measurements on the samples indicated that they were not affected by modifications in the oxygen-to-metal ratio during annealing. The grain size distributions inferred by means of image analysis of metallographic pictures reveal that, when taking into account the experimental uncertainties, the grain growth kinetics are similar to those observed in conventional UO2 fuel that was also tested under the same conditions. An analysis of experimental data available in the open literature for both UO2 and MOX fuel leads to the same conclusion. It is therefore suggested that grain growth models for UO2 fuel can be applied to MOX fuel for fuel performance simulations, when taking into consideration the uncertainties pertaining to grain growth measurements

  19. Pulmonary interstitial glycogenosis in the setting of lung growth abnormality: radiographic and pathologic correlation

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, Monette; Vade, Aruna; Lim-Dunham, Jennifer Eden [Loyola University Health System, Department of Radiology, Maywood, IL (United States); Masuda, Emi [Henry Ford Hospital, Department of Radiology, Detroit, MI (United States); Massarani-Wafai, Rasan [Loyola University Health System, Department of Pathology, Maywood, IL (United States)

    2010-09-15

    Pulmonary interstitial glycogenosis (PIG) is a rare pediatric interstitial lung disease. We report a case of a term boy presenting with tachypnea at birth requiring supplemental oxygen. Chest radiographs followed by high-resolution CT (HRCT) demonstrated hyperinflation and diffuse interstitial markings interspersed with multiple cystic spaces. An open lung biopsy demonstrated a minor component of PIG superimposed upon poor alveolarization. PIG in the setting of lung growth abnormality might be more common than previously described. Additionally, radiographic findings associated with most pediatric interstitial lung diseases are nonspecific, and histopathologic correlation is essential for diagnosis. (orig.)

  20. Crystal grain growth during room temperature high pressure Martensitic alpha to omega transformation in zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Velisavljevic, Nenad [Los Alamos National Laboratory; Chesnut, Gary N [Los Alamos National Laboratory; Stevens, Lewis L [Los Alamos National Laboratory; Dattelbaum, Dana M [Los Alamos National Laboratory

    2008-01-01

    Systematic increase in transition pressure with increase in interstitial impurities is observed for the martensitic {alpha} {yields} {omega} structural phase transition in Zr. Significant room temperature crystal grain growth is also observed for the two highest purity samples at this transition, while in the case of the lowest purity sample interstitial impurities obstruct grain growth even as the sample is heated to 1279 K. Our results show the importance of impurities in controlling structural phase stability and other mechanical properties associated with the {alpha} {yields} {omega} structural phase transition.

  1. Chemically driven growth of tungsten grains during liquid phase sintering of W-Ni-Fe alloys

    International Nuclear Information System (INIS)

    In the alloys where the solid grains immersed in liquid matrix grow by Ostwald ripening process, the growth rate can be suddenly altered by changing the matrix composition. In this study, W-Ni-(Fe) specimens have been sintered and annealed at the temperatures around 15000C until the grains have coarsened, and then annealed further after adding Fe or Ni. After adding Fe or Ni and further annealing treatments, strong etching has revealed that a new solid phase in equilibrium with the changed matrix composition has been deposited preferentially on the larger grains. The smaller grains, which would be dissolving continuously, have maintained the old composition. This composition difference between the new solid phase on the larger grains and the old solid phase on the smaller ones can provide a driving force for grain coarsening in addition to that arising from the size difference. When Fe is added to sintered W-Ni, the grain coarsening rate during further annealing momentarily increases. The calculation shows that the molar free energy of the new solid phase should be lower than that of the old solid phase. Therefore, the solution reprecipitation process is ascelerated by this chemical free energy difference. If, on the other hand, Ni is added to sintered W-Ni-Fe, the coarsening rate decreases during further annealing. The calculation shows indeed that in this case the new solid phase should have higher molar free energy than the old. It is therefore demonstrated that if the matrix composition is altered during Ostwald ripening, the grain coarsening can be accelerated or retarded because of the chemical composition difference between the old grains and the newly precipitated solid phase on the larger grains. (author)

  2. Stochastic simulation of grain growth during continuous casting

    International Nuclear Information System (INIS)

    The evolution of microstructure is a very important topic in material science engineering because the solidification conditions of steel billets during continuous casting process affect directly the properties of the final products. In this paper a mathematical model is described in order to simulate the dendritic growth using data of real casting operations; here a combination of deterministic and stochastic methods was used as a function of the solidification time of every node in order to create a reconstruction about the morphology of cast structures

  3. Recrystallization and grain growth induced by ELMs-like transient heat loads in deformed tungsten samples.

    Science.gov (United States)

    Suslova, A; El-Atwani, O; Sagapuram, D; Harilal, S S; Hassanein, A

    2014-11-04

    Tungsten has been chosen as the main candidate for plasma facing components (PFCs) due to its superior properties under extreme operating conditions in future nuclear fusion reactors such as ITER. One of the serious issues for PFCs is the high heat load during transient events such as ELMs and disruption in the reactor. Recrystallization and grain size growth in PFC materials caused by transients are undesirable changes in the material, since the isotropic microstructure developed after recrystallization exhibits a higher ductile-to-brittle transition temperature which increases with the grain size, a lower thermal shock fatigue resistance, a lower mechanical strength, and an increased surface roughening. The current work was focused on careful determination of the threshold parameters for surface recrystallization, grain growth rate, and thermal shock fatigue resistance under ELM-like transient heat events. Transient heat loads were simulated using long pulse laser beams for two different grades of ultrafine-grained tungsten. It was observed that cold rolled tungsten demonstrated better power handling capabilities and higher thermal stress fatigue resistance compared to severely deformed tungsten. Higher recrystallization threshold, slower grain growth, and lower degree of surface roughening were observed in the cold rolled tungsten.

  4. The Growth Path of Agricultural Labor Productivity in Major Grain Producing Areas

    Institute of Scientific and Technical Information of China (English)

    Ning; ZHOU; Qifeng; CUI

    2014-01-01

    The growth of agricultural labor productivity in major grain producing areas arises from the increase in production factors or improvement of efficiency,and is related to the sustainability of agricultural economic growth and national food security. We study the growth path of agricultural labor productivity in 13 major grain producing areas of China,and the analysis results show that from the relative endowments of land and labor in major grain producing areas,the growth rate of the output value per unit of labor is higher than that of the productivity per unit of land; in essence,this growth path of increasing the output value relying on increasing the production factor inputs is the reduction of labor,and the reduction of agricultural labor has a great elasticity of impact on the total value of agricultural production. In the case of stable future number of agricultural labor in China,the growth of agricultural labor productivity will be impossible to rely more on the increase in agricultural production factor inputs,and the growth path of agricultural economy still has to rely on the improvement of land productivity and take the efficiency-based path.

  5. EFFECT OF STRONTIUM OXIDE ON GRAIN GROWTH AND DENSIFICATION IN BNN SYSTEM

    Directory of Open Access Journals (Sweden)

    CHANDRA SEKHAR BEERA

    2013-02-01

    Full Text Available Grain size and density parameters have been investigated in SrO added Tungsten Bronze (TB type Ferroelectric Barium Sodium Niobate (BNN ceramic as a function of sintering time and sintering temperature. Addition of SrO has greatly improved the density of the system. The sample BNN with 3% SrO has showed above 95% of theoretical density. Scanning Electron Micrographs revealed normal grain growth in the present study. Activation energies for the formation of grain growth and densification in all the samples have been estimated and found lying in the range of 50-60 kcal/mole. The results are discussed in the light of present understanding.

  6. Experimental study on grain and pore growth of Niobia-added UO2 pellets

    International Nuclear Information System (INIS)

    An experimental study on niobia-added UO2 had been done with aid of x-ray diffraction and metallography. It was observed that Nb5+ ions were very difficult to occupy UO2 only at the sample with y = 0.01 (where y=Nb/(Nb+U) atomic ratio). The second, second phase appeared at the samples with larger y. It was preferable that the rapid grain and pore growth is based on the theory expressing that occupation of Nb5+ ions UO2 crystal produces oxygen interstitial that then active grain and intergranular pore growth. It was known also that second phase containing uranium and niobium with low melting point (lower than 1390oC was formed at the samples with large y. The second phase melted during sintering and created rounded grains in the pellets

  7. Study of Grain Growth of CZTS Nanoparticles Annealed in Sulfur Atmosphere

    DEFF Research Database (Denmark)

    Engberg, Sara Lena Josefin; Crovetto, Andrea; Hansen, Ole;

    2014-01-01

    of the main limitations for this approach, and (2) that grain boundaries and defects are believed to be a site for recombination that limits the efficiency. Annealing in vacuum and/or a nitrogen atmosphere facilitates grain growth and improves the electronic properties. Conventionally selenization (annealing...... in selenium) shows the best results, however sulfurization (annealing in sulfur) has the advantage of leading to a non-toxic material. In this work, nanocrystals of CZTS with a targeted Cu-poor/Zn-rich composition are synthesized through a hot-injection method with oleylamine as the solvent. The nanocrystal...... inks are deposited through doctor blading in octanethiol, and annealed in a vacuum furnace using a graphite box with sulfur. The surface morphology and thus grain growth are studied for various annealing conditions in a 10-mbar nitrogen atmosphere with a varying amount of sulfur.The films...

  8. Grain boundary microstructure and fatigue crack growth in Allvac 718Plus superalloy

    International Nuclear Information System (INIS)

    Research highlights: → Hold-time crack growth rates for Allvac 718Plus are shown to be affected by delta-phase. → Delta-phase is shown to alter microstructure and chemistry at and about grain boundaries. → Two types of oxides were found and their presence was linked to the different fracture modes. - Abstract: The correlation between grain boundary microstructure and fatigue crack growth with hold-times was investigated for two conditions of the superalloy Allvac 718Plus; a Standard condition with the recommended distribution of grain boundary phases and a Clean condition with virtually no grain boundary phases. Fatigue testing was performed at 704 deg. C using 10 Hz cyclic load with intermittent hold-times of 100 s at maximum tensile load. Microstructural characterization and fractography were conducted using scanning- and transmission electron microscopy techniques. Auger electron- and X-ray photoelectron spectroscopy techniques were used for oxide analyses on fracture surfaces. It was found that in the Standard condition crack growth is mostly transgranular for 10 Hz loading and intergranular for hold-times, while for the Clean condition crack growth is intergranular in both load modes. The lower hold-time crack growth rates in the Standard condition are attributed to grain boundary δ-phase precipitates. No effect of δ-phase was observed for 10 Hz cyclic loading crack growth rates. Two different types of oxides and oxide colours were found on the fracture surfaces in the Standard condition and could be correlated to the different loading modes. For cyclic loading a bright thin Cr-enriched oxide was dominate and for hold-times a dark and slightly thicker Nb-enriched oxide was dominant These oxide types could be related to the oxidation of δ-phase and the matrix respectively. The influence of δ-phase precipitates on crack propagation is discussed.

  9. Reaction induced nucleation and growth v. grain coarsening in contact metamorphic, impure carbonates

    DEFF Research Database (Denmark)

    Berger, Alfons; Brodhag, Sabine; Herwegh, Marco

    2010-01-01

    , although the latter formed later but at higher temperatures. Moreover, different kinetic processes, attributed to different driving forces for growth of the newly nucleated grains in comparison with coarsening processes of the pre-existing phases, must have been involved. Chemically induced driving forces...

  10. CULTIVAR RELEASE - BRS Esplendor – Common bean cultivar with black grain, upright growth and disease resistance

    Directory of Open Access Journals (Sweden)

    Joaquim Geraldo Cáprio da Costa

    2011-01-01

    Full Text Available BRS Esplendor is a common bean cultivar with black grain, suitable for 12 Brazilian states. The mean productivity is 2,156 kg ha-1, by 7.5 % higher than of controls, has a high yield potential (4,120 kg ha-1, upright growth, high tolerance to lodging and high resistance to anthracnose, fusarium wilt and common bacterial blight.

  11. Watching the growth of bulk grains during recrystallization of deformed metals

    DEFF Research Database (Denmark)

    Schmidt, Søren; Fæster Nielsen, Søren; Gundlach, C.;

    2004-01-01

    , contradicting the classical assumption of smooth and spherical growth of new grains during recrystallization. This type of in situ bulk measurement opens up the possibility of obtaining experimental data on scientific topics that before could only be analyzed theoretically on the basis of the statistical...

  12. Grain growth signatures in the protoplanetary discs of Chamaeleon and Lupus

    CERN Document Server

    Ubach, Catarina; Wright, Christopher M; Wilner, David J; Lommen, Dave J P; Koribalski, Baerbel

    2012-01-01

    We present ATCA results of a 3 and 7 mm continuum survey of 20 T Tauri stars in the Chamaeleon and Lupus star forming regions. This survey aims to identify protoplanetary discs with signs of grain growth. We detected 90% of the sources at 3 and 7 mm, and determined the spectral slopes, dust opacity indices and dust disc masses. We also present temporal monitoring results of a small sub-set of sources at 7, 15 mm and 3+6 cm to investigate grain growth to cm sizes and constrain emission mechanisms in these sources. Additionally, we investigated the potential correlation between grain growth signatures in the infrared (10 \\mu m silicate feature) and millimetre (1-3 mm spectral slope, {\\alpha}). Eleven sources at 3 and 7 mm have dominant thermal dust emission up to 7 mm, with 7 of these having a 1-3 mm dust opacity index less than unity, suggesting grain growth up to at least mm sizes. The Chamaeleon sources observed at 15 mm and beyond show the presence of excess emission from an ionised wind and/or chromo- sphe...

  13. A Multi-Wavelength Study of Grain Growth in Protoplanetary Disks

    Science.gov (United States)

    Ubach, Catarina

    2014-01-01

    Protoplanetary disk around young stellar objects contain the building blocks of planets. Observations at millimeter wavelengths are used to directly probe the cooler outer regions and mid-plane of the disk where the bulk of the dust resides. Observations at 1 and 3 mm can provide signatures of growth to mm-sized grains. Signatures of grains up to cm sizes can only be obtained by increasing the observing wavelength to 7 and 15 mm. If thermal dust emission dominates at 7 mm and beyond, the spectral slope should remain constant into the cm bands. However, as the observing wavelength is increased from 3 to 7 and 15 mm, other forms of emission besides thermal dust emission can also be present. The contributions from other processes cause an excess in flux above the expected thermal dust emission, and thus disentangling the emission mechanisms is required before conclusions can be made about the maximum grain size. We present results of our Australia Telescope Compact Array 3 and 7 mm continuum survey of 20 T Tauri stars, which aims to identify protoplanetary disks with signs of grain growth and temporal monitoring results of a sub-set of sources at 7, 15 mm and 3+6 cm to investigate grain growth up to cm sizes and disentangle the emission mechanisms present in these sources. We found 11 sources have dominant thermal dust emission up to 7 mm, with 7 of these having a 1-3 mm dust opacity index < 1, suggesting grain growth up to at least mm sizes. Sources observed at 15 mm and beyond show the presence of excess emission from multiple emission mechanisms. Long timescale monitoring at 7 mm indicates that cm-sized pebbles are present in at least 4 sources, while short timescale monitoring at 15 mm suggests the excess emission is from thermal free-free emission. These results provide evidence that grain growth up to cm-sized pebbles and the presence of excess emission at 7 mm and beyond are common in these systems, and to disentangle the thermal dust emission from other

  14. Grain growth of nanocrystalline 3C-SiC under Au ion irradiation at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Limin; Jiang, Weilin; Dissanayake, Amila C.; Varga, Tamas; Zhang, Jiandong; Zhu, Zihua; Hu, Dehong; Wang, Haiyan; Henager, Charles H.; Wang, Tieshan

    2016-01-09

    Nanocrystalline silicon carbide (SiC) represents an excellent model system for a fundamental study of interfacial (grain boundary) processes under nuclear radiation, which are critical to the understanding of the response of nanostructured materials to high-dose irradiation. This study reports on a comparison of irradiation effects in cubic phase SiC (3C-SiC) grains of a few nanometers in size and single-crystal 3C-SiC films under identical Au ion irradiation to a range of doses at 700 K. In contrast to the latter, in which lattice disorder is accumulated to a saturation level without full amorphization, the average grain size of the former increases with dose following a power-law trend. In addition to coalescence, the grain grows through atomic jumps and mass transport, where irradiation induced vacancies at grain boundaries assist the processes. It is found that a higher irradiation temperature leads to slower grain growth and a faster approach to a saturation size of SiC nanograins. The results could potentially have a positive impact on structural components of advanced nuclear energy systems.

  15. Evolution of the Annealing Twin Density during δ-Supersolvus Grain Growth in the Nickel-Based Superalloy Inconel™ 718

    Directory of Open Access Journals (Sweden)

    Yuan Jin

    2015-12-01

    Full Text Available Grain growth experiments were performed on Inconel™ 718 to investigate the possible correlation of the annealing twin density with grain size and with annealing temperature. Those experiments were conducted at different temperatures in the δ supersolvus domain and under such conditions that only capillarity forces were involved in the grain boundary migration process. In the investigated range, there is a strong inverse correlation of the twin density with the average grain size. On the other hand, the twin density at a given average grain size is not sensitive to annealing temperature. Consistent with previous results for pure nickel, the twin density evolution in Inconel™ 718 is likely to be mainly controlled by the propagation of the pre-existing twins of the growing grains; i.e., the largest ones of the initial microstructure. Almost no new twin boundaries are created during the grain growth process itself. Therefore, the twin density at a given average grain size is mainly dependent on the twin density in the largest grains of the initial microstructure and independent of the temperature at which grains grow. Based on the observations, a mean field model is proposed to predict annealing twin density as a function of grain size during grain growth.

  16. Centre seeded infiltration and growth process for fabrication of large grain bulk YBCO/Ag superconducting composites

    Science.gov (United States)

    Parthasarathy, R.; Seshubai, V.

    2012-06-01

    We report the fabrication of a large grain bulk YBCO/Ag superconductor using a novel technique which we call Centre Seeded Infiltration and Growth Process (CSIGP). Using this technique, it has been made possible to get bulk YBCO/Ag composite sample with uniform grain growth textured along the c-axis. The resulting large grain sample has been found to have high critical current densities up to large magnetic fields. We correlate the improved superconducting and magnetic properties to the modified grain growth conditions employed in this fabrication technique.

  17. Geometric and topological properties of the canonical grain-growth microstructure.

    Science.gov (United States)

    Mason, Jeremy K; Lazar, Emanuel A; MacPherson, Robert D; Srolovitz, David J

    2015-12-01

    Many physical systems can be modeled as large sets of domains "glued" together along boundaries-biological cells meet along cell membranes, soap bubbles meet along thin films, countries meet along geopolitical boundaries, and metallic crystals meet along grain interfaces. Each class of microstructures results from a complex interplay of initial conditions and particular evolutionary dynamics. The statistical steady-state microstructure resulting from isotropic grain growth of a polycrystalline material is canonical in that it is the simplest example of a cellular microstructure resulting from a gradient flow of an energy that is directly proportional to the total length or area of all cell boundaries. As many properties of polycrystalline materials depend on their underlying microstructure, a more complete understanding of the grain growth steady state can provide insight into the physics of a broad range of everyday materials. In this paper we report geometric and topological features of these canonical two- and three-dimensional steady-state microstructures obtained through extensive simulations of isotropic grain growth. PMID:26764854

  18. Anomalous grain growth in nanocrystalline Fe73.5Cu1Nb3Su13.5B9 alloys

    DEFF Research Database (Denmark)

    Jiang, Jianzhong

    1997-01-01

    The grain growth of the FeSi phase during the crystallization process of the amorphous Fe73.5Cu1Nb3Si13.5B9 alloy was studied using transmission electron microscopy and x-ray diffractometry. An anomalous grain growth behaviour of the FeSi phase in the samples annealed in temperature range from 74...

  19. Grain growth and Ostwald ripening in chromia-doped uranium dioxide

    International Nuclear Information System (INIS)

    The use of solid solution additives such as ''corundum'' types oxides is a practical mean for enhancing grain growth of stoichiometric uranium dioxide. The present paper deals with chromia-doped UO2 samples. Large-grain sized fuels can be produce by addition of less than 1000 ppm of chromia to UO2 powder prior to sintering. Above the solubility limit, excess of insoluble Cr2O3 precipitates from solid solution to create second phase inclusions in UO2 matrix. These inclusions coalesce by an Ostwald ripening phenomenon. (orig.)

  20. Grain growth and Ostwald ripening in chromia-doped uranium dioxide

    OpenAIRE

    V. Peres; Bourgeois, L.; Dehaudt, P.

    1993-01-01

    The use of solid solution additives such as "corundum" types oxides is a practical mean for enhancing grain growth of stoichiometric uranium dioxide. The present paper deals with chromia-doped UO2 samples. Large-grain sized fuels can be produce by addition of less than 1000 ppm of chromia to UO2 powder prior to sintering. Above the solubility limit, excess of insoluble Cr2O3 precipitates from solid solution to create second phase inclusions in UO2 matrix. These inclusions coalesce by an Ostwa...

  1. A low temperature synthesized NbC grain growth inhibitor in WC-Co hardmetal alloy

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, U.U.; Silva, A.G.P. da [Dept. de Fisica, Univ. Federal do Rio Grande do Norte, Natal, RN (Brazil); Souza, C. de; Medeiros, F.F.P. [Dept. de Quimica, Univ. Federal do Rio Grande do Norte, Natal RN (Brazil); Ciaravino, C.; Roubin, M. [Lab. de Physico-Chimie des Materiaux, LPCM3, Univ. de Toulon, La Garde (France)

    2001-07-01

    The efficiency of NbC on WC grain coarsening in a WC-10wt.%Co hardmetal alloy was demonstrated by hardness measurement and WC granulation observation. The heterogeneous and overall grain growth were controlled. A low temperature experimentally produced NbC was used and compared to the inhibition potential of a commercial NbC powder. The results were the same in terms of structural fineness and hardness. The dispersion of the experimental NbC was not a problem, in spite of its size. The experimental NbC has very large particles, formed by agglomerates of small crystallites. During milling these agglomerates could be broken down. (orig.)

  2. Grain growth and temperature distribution in the irradiated fuel elements designed for Qinshan Power Plant

    International Nuclear Information System (INIS)

    The micro-analysis results of UO2 fuel core of irradiated test elements designed for Qinshan Power Plant are presented. The temperature of element centers is quantitatively calculated by using the grain size measurement results according to the principle of grain growth dynamics, and the results are in accordance with that of the FRAP-CON calculation. Based on the post-irradiation examination data, the dynamic parameters, K and Q which are particularly suitable to description of irradiation behaviours of UO2 fuel made in China are deduced

  3. CELLULAR AUTOMATA MODELLING OF GRAIN COARSENING DURING REIHEATING AND VALIDATION WITH THE EXPERIMENTAL RESULTS

    Institute of Scientific and Technical Information of China (English)

    W.H. Yu; E.J. Palmiere; S.P. Banks; J.T. Han

    2005-01-01

    A novel 2D cellular automata (CA) model has been developed for description of normal grain coarsening and abnormal grain coarsening process. The program reflects the grain coarsening quite well even through the average grain size becomes very large. Follow results have been obtained: (a) The model reflect the normal grain growth kinetics gradually increase with probability and grain growth speed can be controlled. Based on this result, temperature can be coupled in the model. (b) Abnormal grain growth is modelled successfully. (c) Methodology has been put forward to find the relationship between the experiment results and modelling results. The experimental work on the grain coarsening has been carried out. Graphical output matched the realistic microstructure in every detail. Because many physical parameters can be taken into account in the CA programme, this CA model could not only qualitatively demonstrate the grain growth process, but also quantitatively predict and analyse the grain coarsening process.

  4. Abnormal test growth in benthic foraminifera from hypersaline coastal ponds of the United Arab Emirates

    Science.gov (United States)

    Fiorini, Flavia; Lokier, Stephen W.

    2014-05-01

    The living (Rose-Bengal stained) benthic foraminifera assemblage from shallow coastal ponds located in the intertidal area of the United Arab Emirate Western Region was investigated. The studied coastal ponds are located between a lagoonal area, characterized by carbonate sedimentation, and the supratidal, evaporite-dominated, sabkha. Sampling was undertaken when the maximum water depth in the ponds was 50 cm with a water temperature ranging from 27 to 35°C, a pH of 8 and a maximum salinity of 60 ppt. The sides and floor of the pond were characterized by a microbial mat. Detached blades of sea grass were present in the ponds and are inferred to have been transported into the pond either during high-tides or storm surges. Collected samples were stained with Rose-Bengal at the moment of sample collection and the living assemblage was studied. The benthic foraminifera that were present show a low-diversity assemblage. Epiphytic larger benthic foraminifera dominate the living assemblage with Peneroplis pertusus and P. planatus characterizing 90% of the living assemblage and the species Spirolina areatina, S. aciculata, Sorites marginalis and Quinqueloculina spp. comprising the rest of the foraminifera community. High percentages (up to 50% of the stained assemblage) of anomalous tests of benthic foraminifera belonging to the genera Peneroplis, Spirolina and Sorites were observed. The anomalies included dissolution, microboring and abnormality in growth. Three different forms of abnormal shell architecture were recorded; the presence of multiple apertures with reduced size, deformation in the general shape of the test and abnormal coiling. The high percentage of abnormal tests reflects natural environmental stress caused by instability of physical parameters (particularly high and variable salinity and temperature) in this kind of transitional marine environment. The unique presence of epiphytic species, suggests that epiphytic foraminifera may be transported into the

  5. Effects of Rice Variety and Growth Location in Cambodia on Grain Composition and Starch Structure

    Institute of Scientific and Technical Information of China (English)

    Seila SAR; Morgan J.TIZZOTTI; Jovin HASJIM; Robert G.GILBERT

    2014-01-01

    The effects of variety and growth location on grain composition and starch structures were investigated using three rice (Oryza sativa L.) cultivars (Phka Romduol, Sen Pidao and IR66) with different amylose contents. All the three cultivars were planted in three different agro-climatic zones (Phnom Penh, Coastal and Plateau) of Cambodia. The protein content of polished grains increased when rice was planted at a location with higher average temperature, but their lipid content decreased. The amylose content and degree of branching were not greatly affected by the minor temperature differences among the growing locations. Starch fine structures characterized by the chain-length distribution were significantly different among the cultivars, but not significantly among different locations. The results suggested that protein and lipid biosyntheses were more sensitive to the environmental temperature than that of starch in rice grains.

  6. Effects of Aerated Irrigation on Leaf Senescence at Late Growth Stage and Grain Yield of Rice

    Institute of Scientific and Technical Information of China (English)

    ZHU Lian-feng; Yu Sheng-miao; JIN Qian-yu

    2012-01-01

    With the japonica inbred cultivar Xiushui 09,indica hybrid combinations Guodao 6 and Liangyoupeijiu as materials,field experiments were conducted in 2007 and 2008 to study the effects of aerated irrigation on leaf senescence at late growth stage and grain yield of rice.The dissolved oxygen concentration of aerated water evidently increased and decreased at a slow rate.The soil oxidation-reduction potential under aerated irrigation treatment was significantly higher than that of the CK,contributing to significant increases in effective panicles,seed setting rate and grain yield.In addition,the aerated irrigation improved root function,increased superoxide dismutase activity and decreased malondialdehyde content in flag leaves at post-flowering,which delayed leaf senescence process,prolonged leaf functional activity and led to enhanced grain filling.

  7. Abnormalities of the axial and proximal appendicular skeleton in adults with Laron syndrome (growth hormone insensitivity)

    Energy Technology Data Exchange (ETDEWEB)

    Kornreich, L.; Konen, O.; Schwarz, M.; Horev, G. [Schneider Children' s Medical Center of Israel, Imaging Department, Petah Tiqwa (Israel); Tel Aviv University, Sackler Faculty of Medicine, Tel Aviv (Israel); Siegel, Y. [Rabin Medical Center, Imaging Department, Petah Tiqwa (Israel); Jackson Memorial Hospital, Department of Radiology, Thoracic Section, Miami, FL (United States); Hershkovitz, I. [Tel Aviv University, Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv (Israel); Laron, Z. [Schneider Children' s Medical Center of Israel, Endocrinology and Diabetes Research Unit, Petah Tiqwa (Israel); Tel Aviv University, Sackler Faculty of Medicine, Tel Aviv (Israel)

    2008-02-15

    To investigate abnormalities in the skeleton (with the exclusion of the skull, cervical spine, hands and feet) in patients with Laron syndrome, who have an inborn growth hormone resistance and congenital insulin-like growth factor-1 (IGF-1) deficiency. The study group was composed of 15 untreated patients with Laron syndrome (seven male and eight female) aged 21-68 years. Plain films of the axial and appendicular skeleton were evaluated retrospectively for abnormalities in structure and shape. The cortical width of the long bones was evaluated qualitatively and quantitatively (in the upper humerus and mid-femur), and the cortical index was calculated and compared with published references. Measurements were taken of the mid-anteroposterior and cranio-caudal diameters of the vertebral body and spinous process at L3, the interpedicular distance at L1 and L5, and the sacral slope. Thoracic and lumbar osteophytes were graded on a 5-point scale. Values were compared with a control group of 20 healthy persons matched for age. The skeleton appeared small in all patients. No signs of osteopenia were visible. The cortex of the long bones appeared thick in the upper limbs in 11 patients and in the lower limbs in four. Compared with the reference values, the cortical width was thicker than average in the humerus and thinner in the femur. The vertebral diameters at L3 and the interpedicular distances at L1 and L5 were significantly smaller in the patients than in the control subjects (P < 0.001); however, at L5 the canal was wider, relative to the vertebral body. The study group had a higher rate of anterior osteophytes in the lumbar spine than the controls had, and their osteophytes were also significantly larger. In the six patients for whom radiographs of the upper extremity in its entirety were available on one film, the ulna appeared to be rotated. In one 22-year-old man, multiple epiphyses were still open. Congenital IGF-1 deficiency leads to skeletal abnormalities

  8. Kinetics of Austenite Grain Growth During Heating and Its Influence on Hot Deformation of LZ50 Steel

    Science.gov (United States)

    Du, Shiwen; Li, Yongtang; Zheng, Yi

    2016-07-01

    Grain growth behaviors of LZ50 have been systematically investigated for various temperatures and holding times. Quantitative evaluations of the grain growth kinetics over a wide range of temperature (950-1200 °C) and holding time (10-180 min) have been performed. With the holding time kept constant, the average austenite grain size has an exponential relationship with the heating temperature, while with the heating temperature kept constant, the relationship between the austenite average grain size and holding time is a parabolic curve approximately. The holding time dependence of average austenite grain size obeys the Beck's equation. As the heating temperature increases, the time exponent for grain growth n increases from 0.21 to 0.39. On the basis of previous models and experimental results, taking the initial grain size into account, the mathematical model for austenite grain growth of LZ50 during isothermal heating and non-isothermal heating is proposed. The effects of initial austenite grain size on hot deformation behavior of LZ50 are analyzed through true stress-strain curves under different deformation conditions. Initial grain size has a slight effect on peak stress.

  9. An analytical model for stress-induced grain growth in the presence of both second-phase particles and solute segregation at grain boundaries

    International Nuclear Information System (INIS)

    A theoretical framework that incorporates the influence of second-phase particles and solute segregation at grain boundaries (GBs) on stress-induced GB migration and grain rotation is formulated in the present paper. In our work, we modified the well-established Cahn–Taylor model to account for the drag stresses generated by second-phase particles and by solute atoms segregated at GBs. The theoretical framework is then implemented to rationalize GB migration and grain rotation using experimental data from a previously published study on stress-induced grain growth in the presence of both second-phase particles and solute segregation at GBs. The calculated grain growth results are generally consistent with the experimental data, providing support to the proposed theoretical model, despite the various assumptions involved. Moreover, the influence of second-phase particles and solute segregation at GBs on GB migration and grain rotation was also investigated using the model, and our results suggest that both second-phase particles and solute atoms segregated at GBs reduce the velocities of GB migration and grain rotation as compared to those in the case of high-purity Al

  10. Effect of solidification rate on competitive grain growth in directional solidification of a nickel-base superalloy

    Institute of Scientific and Technical Information of China (English)

    ZHOU YiZhou; SUN XiaoFeng

    2012-01-01

    The mechanism of grain structure evolution during directional solidification is a fundamental subject in material science.Within the published research there exist conflicting views on the mechanism of grain overgrowth.To study the effect of solidification rate on grain structure evolution,bi-crystals samples were produced in a nickel-base superalloy at different solidification rates.It was found that at the convergent grain boundaries those grains better aligned with respect to the heat flux more readily overgrew neighbouring grains with misaligned orientations and the effect became more pronounced as solidification rate was increased.However,at diverging grain boundaries the rate of overgrowth was invariant to the solidification rate.These experimental results were compared with models in the literature.Thus,a better insight into competitive grain growth in directional solidification processes was obtained.

  11. Investigating grain growth in disks around southern T Tauri stars at millimetre wavelengths

    CERN Document Server

    Lommen, D; Maddison, S T; Jørgensen, J K; Bourke, T L; Van Dishoeck, E F; Hughes, A; Wilner, D J; Burton, M; Van Langevelde, H J; Lommen, Dave; Wright, Chris M.; Maddison, Sarah T.; Jorgensen, Jes K.; Bourke, Tyler L.; Dishoeck, Ewine F. van; Hughes, Annie; Wilner, David J.; Burton, Michael; Langevelde, Huib Jan van

    2006-01-01

    CONTEXT - Low-mass stars form with disks in which the coagulation of grains may eventually lead to the formation of planets. It is not known when and where grain growth occurs, as models that explain the observations are often degenerate. A way to break this degeneracy is to resolve the sources under study. AIMS - To find evidence for the existence of grains of millimetre sizes in disks around in T Tauri stars, implying grain growth. METHODS - The Australia Telescope Compact Array (ATCA) was used to observe 15 southern T Tauri stars, five in the constellation Lupus and ten in Chamaeleon, at 3.3 millimetre. The five Lupus sources were also observed with the Submillimeter Array (SMA) at 1.4 millimetre. Our new data are complemented with data from the literature to determine the slopes of the spectral energy distributions in the millimetre regime. RESULTS - Ten sources were detected at better than 3sigma with the ATCA, with sigma ~1-2 mJy, and all sources that were observed with the SMA were detected at better t...

  12. Sintering boron carbide ceramics without grain growth by plastic deformation as the dominant densification mechanism

    Science.gov (United States)

    Ji, Wei; Rehman, Sahibzada Shakir; Wang, Weimin; Wang, Hao; Wang, Yucheng; Zhang, Jinyong; Zhang, Fan; Fu, Zhengyi

    2015-10-01

    A new ceramic sintering approach employing plastic deformation as the dominant mechanism is proposed, at low temperature close to the onset point of grain growth and under high pressure. Based on this route, fully dense boron carbide without grain growth can be prepared at 1,675-1,700 °C and under pressure of (≥) 80 MPa in 5 minutes. The dense boron carbide shows excellent mechanical properties, including Vickers hardness of 37.8 GPa, flexural strength of 445.3 MPa and fracture toughness of 4.7 MPa•m0.5. Such a process should also facilitate the cost-effective preparation of other advanced ceramics for practical applications.

  13. Sintering boron carbide ceramics without grain growth by plastic deformation as the dominant densification mechanism.

    Science.gov (United States)

    Ji, Wei; Rehman, Sahibzada Shakir; Wang, Weimin; Wang, Hao; Wang, Yucheng; Zhang, Jinyong; Zhang, Fan; Fu, Zhengyi

    2015-10-27

    A new ceramic sintering approach employing plastic deformation as the dominant mechanism is proposed, at low temperature close to the onset point of grain growth and under high pressure. Based on this route, fully dense boron carbide without grain growth can be prepared at 1,675-1,700 °C and under pressure of (≥) 80 MPa in 5 minutes. The dense boron carbide shows excellent mechanical properties, including Vickers hardness of 37.8 GPa, flexural strength of 445.3 MPa and fracture toughness of 4.7 MPa•m(0.5). Such a process should also facilitate the cost-effective preparation of other advanced ceramics for practical applications.

  14. MODELING AND SIMULATION OF DYNAMIC RECRYSTALLIZATION AND GRAIN GROWTH DURING HOT WORKING OF INCONEL 783 SUPERALLOY

    OpenAIRE

    JONG-TAEK YEOM; EUN JEOUNG JUNG; JEE HOON KIM; JEOUNG HAN KIM; JAE-KEUN HONG; NHO-KWANG PARK; KOOK-JOO KIM; SEUNG-SIK CHOI

    2010-01-01

    In this study, the modeling of recrystallization and grain growth was investigated to predict the microstructure evolution during hot working of INCONEL 783 superalloy (Alloy 783). The recrystallization model was constructed on the basis of the Avrami formation. A least-square optimization technique was used to determine several important parameters within the model from isothermal heat treatment and hot compression test results. High temperature compression tests were carried out under diffe...

  15. A Paradox of Decreasing Entropy in Multiscale Monte Carlo Grain Growth Simulations

    OpenAIRE

    Esche, Sven K.; Michael Nosonovsky

    2008-01-01

    Grain growth in metals is driven by random thermal fluctuations and increases the orderliness of the system. This random process is usually simulated by the Monte Carlo (MC) method and Cellular Automata (CA). The increasing orderliness results in an entropy decrease, thus leading to a paradoxical apparent violation of the second law of thermodynamics. In this paper, it is shown that treating the system as a multiscale system resolves this paradox. MC/CA simulations usually take into considera...

  16. The role of grain boundary structure and crystal orientation on crack growth asymmetry in aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Adlakha, I. [School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ 85287 (United States); Tschopp, M.A. [U.S. Army Research Laboratory, Aberdeen Proving Ground, MD 21005 (United States); Solanki, K.N., E-mail: kiran.solanki@asu.edu [School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ 85287 (United States)

    2014-11-17

    Atomistic simulations have shown that the grain boundary (GB) structure affects a number of physical, mechanical, thermal, and chemical properties, which can have a profound effect on macroscopic properties of polycrystalline materials. The research objective herein is to use atomistic simulations to explore the role that GB structure and the adjacent crystallographic orientations have on the directional asymmetry of an intergranular crack (i.e. cleavage behavior is favored along one direction, while ductile behavior along the other direction of the interface) for aluminum grain boundaries. Simulation results from seven 〈110〉 symmetric tilt grain boundaries (STGBs) show that the GB structure and the associated free volume directly influence the stress–strain response, crack growth rate, and crack tip plasticity mechanisms for middle-tension (M(T)) crack propagation specimens. In particular, the structural units present within the GB promote whether a dislocation or twinning-based mechanism operates at the crack tip during intergranular fracture along certain GBs (e.g., the ‘E’ structural unit promotes twinning at the crack tip in Al). Furthermore, the crystallography of the adjacent grains, and therefore the available slip planes, can significantly affect the crack growth rates in both directions of the crack – this creates a strong directional asymmetry in the crack growth rate in the Σ11 (113) and the Σ27 (552) STGBs. Upon comparing these results with the theoretical Rice criterion, it was found that certain GBs in this study (Σ9 (221), Σ11 (332) and Σ33 (441)) show an absence of directional asymmetry in the observed crack growth behavior, in conflict with the Rice criterion. The significance of the present research is that it provides a physical basis for the role of GB character and crystallographic orientation on intergranular crack tip deformation behavior.

  17. Effects of carbon nanotubes incorporation on the grain growth and properties of WC/Co nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Faming; Sun Jianfei; Shen Jun [School of Materials Science and Engineering, Harbin Inst. of Tech. (China)

    2005-07-01

    Carbon nanotubes (CNTs) combining unique mechanical and physical properties could offer a kind of nanosized reinforcements for composite materials. Incorporating of CNTs to develop advance engineering composites has become an interesting concept, but the cermets based CNTs composites have been less focused. WC-Co-CNTs nanocomposites were consolidated by spark plasma sintering (SPS) to investigate the effects of CNTs incorporation on the grain growth and mechanical properties of WC-Co nanocomposites. Experimental results show that CNTs could preserve their tubular structures in high temperature SPS process, some CNTs are surviving in the WC-Co fracture surfaces featured bridging and pulling out manner. The interaction between the CNTs and the matrix has a retardation effect of grain growth of WC, but CNTs additions could be resulted in an increase of carbon content in the binder phase that causes enhanced tendency of grain growth, either of which plays the dominated role depending on the CNTs content. The WC-10Co-0.5wt% CNTs nanocomposites possess superior hardness to toughness combinations, which hardness is about 15% and fracture toughness is about 40% higher than that of the pure nano-WC-10Co cermets consolidated under the same process. (orig.)

  18. Ice Formation and Grain Growth in the Quiescent Medium of the Lupus Molecular Clouds

    Science.gov (United States)

    Boogert, Abraham C.; Chiar, J. E.; Knez, C.; Oberg, K. I.; Mundy, L. G.; Pendleton, Y. J.; Tielens, X.; van Dishoeck, E.

    2014-01-01

    Infrared photometry and spectroscopy of background stars reddened by the Lupus molecular cloud complex are used to determine the properties of the grains and the composition of the ices before they are incorporated into circumstellar envelopes and disks. H2O ices form at extinctions of A_V=2.1+/-0.6. Such a low ice formation threshold is consistent with the absence of nearby hot stars. Overall, the Lupus clouds are in an early chemical phase. The abundance of H2O ice (2.3+/-0.1 10^-5 relative to N_H) is a factor of 3-4 lower compared to dense envelopes of YSOs. CO is not fully frozen out, and a low solid CH3OH abundance is consistent with that. Furthermore it is found that the grains in Lupus experienced growth by coagulation. The mid-infrared continuum extinction relative to A_K increases as a function of A_K. Most Lupus lines of sight are well fitted with extinction curves corresponding to R_ 3.5 and R_ 5.0. The τ_9.7/A_K ratio follows that of dense cores for lines of sight with A_K>1.0 mag. Below 1.0 mag, values scatter between the dense and diffuse medium ratios, indicating that local conditions matter in the process that sets the τ_9.7/A_K ratio. This process is likely related to grain growth, but not to ice mantle formation. Conversely, ice mantles form on grains before the process of grain coagulation has started.

  19. Establishment of growth medium and quantification of pollen grains and germination of pear tree cultivars

    Directory of Open Access Journals (Sweden)

    Paulyene Vieira Nogueira

    2016-06-01

    Full Text Available ABSTRACT To support breeding programs of pear tree, on the selection of cultivars to subtropical area in Brazil, the objective of this research was to adjust the growth medium basic to pollen grain germination. The pollen grains of 'D'Água' cultivar were spread on the surface of Petri dishes containing 20 ml of culture medium in accordance with the following sequential experiments: 1 ágar (4; 6; 8 and 10 g L-1 and pH (3,5; 4,5; 5,5 and 6,5; 2 sucrose (0; 30; 60 and 90 g L-1; 3 calcium nitrate (0; 200; 400 and 800 mg L-1; 4 boric acid (0; 400; 800 and 1200 mg L-1; 5 temperature of incubation (15; 20; 25 e 30 ºC and 6 emission time of the pollen tube (0; 1; 2; 3; 4; 5 and 6 hours after inoculation. After incubation, the germination rate of pollen grains of nine pear cultivars ('Rocha', 'Abate Fetel', 'Packham's Triumph', 'Atago', 'Hosui', 'Primorosa', 'Triunfo', 'Seleta' and 'D'Água' was evaluated, and number of stamens, the number of pollen grains per anther and per flower. The protocol for germination of pollen grains of pear tree consist in the culture medium have to be solidified with 10 g L-1 ágar, being the pH measured to 5,2 , added with 90 g L-1 sucrose, 145 mg L-1 calcium nitrate and 700 mg L-1 boric acid, with incubation temperature of 23 ºC. The readings germination percentage should be performed after five hours of incubation. The pollen grain 'Rocha' cultivar showed higher germination percentage.

  20. NEW ISOTHERMAL MODEL FOR GRAIN GROWTH IN NANOCRYSTALLITES%纳米晶等温生长新模型

    Institute of Scientific and Technical Information of China (English)

    屈一新; 宋晓岚

    2004-01-01

    @@ INTRODUCTION Nanocrystallites with an average grain size of less than 100 nm have attracted considerable scientific interest because of the improvements in a variety of properties resulted from grain-size refinement in the nanometer scale.The investigation of the thermal stability or grain growth behavior is therefore important from the technological point of view as well as for the purpose of scientific study.

  1. Testing the theory of grain growth and fragmentation by millimeter observations of protoplanetary disks

    CERN Document Server

    Birnstiel, T; Trotta, F; Dullemond, C P; Natta, A; Testi, L; Dominik, C; Henning, T; Ormel, C W; Zsom, A

    2010-01-01

    Context. Observations at sub-millimeter and mm wavelengths will in the near future be able to resolve the radial dependence of the mm spectral slope in circumstellar disks with a resolution of around a few AU at the distance of the closest star-forming regions. Aims. We aim to constrain physical models of grain growth and fragmentation by a large sample of (sub-)mm observations of disks around pre-main sequence stars in the Taurus-Auriga and Ophiuchus star-forming regions. Methods. State-of-the-art coagulation/fragmentation and disk-structure codes are coupled to produce steady-state grain size distributions and to predict the spectral slopes at (sub-)mm wavelengths. Results. This work presents the first calculations predicting the mm spectral slope based on a physical model of grain growth. Our models can quite naturally reproduce the observed mm-slopes, but a simultaneous match to the observed range of flux levels can only be reached by a reduction of the dust mass by a factor of a few up to about 30 while ...

  2. Evaluation of Grain Growth of Corn and Sorghum under K2O Application and Irrigation According

    Directory of Open Access Journals (Sweden)

    Sayed Alireza Valadabadi

    2009-08-01

    Full Text Available In this experiment, interactive effects of different potassium application and water restrict on graingrowth in Iran. The experimental unit had designed by achieved treatment in factorial on the basis completelyrandomized block design with three replicates. Certain factors including potassium and non-potassiumapplications (0 and 200 kg/ha, certain field crops (corn and sorghum and w ater supply were studied. In thisstudy crops water supply was determined by indicated irrigation conditions by keeping leaf Relative WaterContent (RW C > 95% (non-drought stress condition or irrigation conditions and drought condition by RWC= 60-70%. We noticed, however K fertilizer significantly increased the grain growth rate of plants and althoughthe non-drought stress treatment significantly increased grain growth rate. Whereas K application persist lessdamaging of drought stress result and it enabled plant to significantly grow its grain under the droughtconditions. Our finding may give applicable advice to commercial farmers and agricultural researches formanagement and concern on fertilizer strategy and carefully estim ate soil potassium supply w ithin dry or semidryareas as most challengeable issues of environmental safety.

  3. A low temperature synthesized NbC as grain growth inhibitor for WC-Co composites

    Energy Technology Data Exchange (ETDEWEB)

    Da Silva, A.G.P.; De Souza, C.P.; Gomes, U.U.; Medeiros, F.F.P. [Rio Grande do Norte Univ., Natal (Brazil); Ciaravino, C.; Roubin, M. [Universite de Toulon et du Var, Laboratoire de Physico-Chimie des Materiaux (LPCM3), Cedex, La Garde (France)

    2000-11-30

    Niobium carbide can be used to inhibit WC grain growth in hardmetal. The performance of a NbC powder produced at low temperature by solid-gas reaction (an experimental powder) as WC grain growth inhibitor is compared with that of a commercial NbC powder. It is verified that NbC effectively inhibits heterogeneous WC coarsening. This results in an increase in hardness. The commercial and experimental NbC powders exhibit a comparable performance in inhibiting the WC grain coarsening, in spite of a significant difference in particle size and shape. The commercial NbC powder is very fine while the experimental one is coarse and porous, but its crystallites are finer than those of the commercial product. The milling procedure used to prepare the alloys is able to reduce the particle size of the experimental NbC, and thus guarantee a dispersion of the particles with a quality level comparable to that found for the alloy prepared with the commercial NbC. (orig.)

  4. Integrating statistical and ecophysiological analysis of genotype by environment interaction for grain filling of barley in Mediterranean areas. II. Grain growth

    NARCIS (Netherlands)

    Voltas, J.; Eeuwijk, van F.A.; Araus, J.L.; Romagosa, I.

    1999-01-01

    In Mediterranean areas, grain growth of temperate cereals often progresses under the harmful influence of drought and high temperature. Genotypic responses are mediated by the specific occurrence of these constraints, thus causing genotype by environment (G × E) interaction. Field experiments were c

  5. ON MODELLING RECRYSTALLIZATION PROCESSES WITH RANDOM GROWTH VELOCITIES OF THE GRAINS IN MATERIALS SCIENCE

    Directory of Open Access Journals (Sweden)

    Elena Villa

    2012-11-01

    Full Text Available Heterogeneous transformations (or reactions  may be defined as those transformations in which there is a sharp moving boundary between the transformed and untransformed region. In Materials Science such transformations are normally called nucleation and growth transformations, whereas birth-and-growth processes is the preferred denomination in Mathematics. Recently, the present authors in a series of papers have derived new analytical expressions for nucleation and growth transformations with the help of stochastic geometry methods. Those papers focused mainly on the role of nuclei location in space, described by point processes, on transformation kinetics.  In this work we focus on the effect that a random velocity of the moving boundaries of the grains has in the overall kinetics. One example of a practical situation in which such a model may be useful is that of recrystallization.  Juul Jensen and Godiksen reviewed recent 3-d experimental results  on recrystallization kinetics and concluded that there is compelling evidence  that  every  grain has its own distinct growth rate. Motivated by this practical application we present here new general kinetics expressions for various situations of practical interest, in which a random distribution of growth velocities is assumed. In order to do this, we  make use of tools from Stochastic Geometry and Geometric Measure Theory. Previously known results follow here as particular cases. Although the motivation for this paper was recrystallization the expressions derived here may be applied to nucleation and growth reactions in general.

  6. Variations in grain lipophilic phytochemicals, proteins and resistance to Fusarium spp. growth during grain storage as affected by biological plant protection with Aureobasidium pullulans (de Bary).

    Science.gov (United States)

    Wachowska, Urszula; Tańska, Małgorzata; Konopka, Iwona

    2016-06-16

    Modern agriculture relies on an integrated approach, where chemical treatment is reduced to a minimum and replaced by biological control that involves the use of active microorganisms. The effect of the antagonistic yeast-like fungus Aureobasidium pullulans on proteins and bioactive compounds (alkylresorcinols, sterols, tocols and carotenoids) in winter wheat grain and on the colonization of wheat kernels by fungal microbiota, mainly Fusarium spp. pathogens, was investigated. Biological treatment contributed to a slight increase contents of tocols, alkylresorcinols and sterols in grain. At the same time, the variation of wheat grain proteins was low and not significant. Application of A. pullulans enhanced the natural yeast colonization after six months of grain storage and inhibited growth of F. culmorum pathogens penetrating wheat kernel. This study demonstrated that an integrated approach of wheat grain protection with the use of the yeast-like fungus A. pullulans reduced kernel colonization by Fusarium spp. pathogens and increased the content of nutritionally beneficial phytochemicals in wheat grain without a loss of gluten proteins responsible for baking value. PMID:27055191

  7. FePt L1{sub 0} ordering and grain growth using millisecond pulse laser processing

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, Yuki [Center for Materials and Information Technology, University of Alabama, Tuscaloosa, AL 35487 (United States); Torres, Karen L. [Department of Metallurgical and Materials Engineering, Box 870202, University of Alabama, Tuscaloosa, AL 35487 (United States); Kang, Shishou [Center for Materials and Information Technology, University of Alabama, Tuscaloosa, AL 35487 (United States); Vanfleet, Richard [Department of Physics and Astronomy, Brigham Young University, Provo, UT 84602 (United States); Izatt, Jerald R. [Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487 (United States); Harrell, J.W. [Center for Materials and Information Technology, University of Alabama, Tuscaloosa, AL 35487 (United States); Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487 (United States); Thompson, Gregory B., E-mail: gthompson@eng.ua.ed [Center for Materials and Information Technology, University of Alabama, Tuscaloosa, AL 35487 (United States); Department of Metallurgical and Materials Engineering, Box 870202, University of Alabama, Tuscaloosa, AL 35487 (United States); Klemmer, Tim; Kubota, Yukiko [Seagate Technology, Fremont, CA 94538 (United States)

    2010-12-15

    The structural and magnetic properties of {approx}12 nm thick FePt thin films grown on Si substrates annealed using a 1064 nm wavelength laser with a 10 ms pulse have been examined. The A1 to L1{sub 0} ordering phase transformation was confirmed by electron and X-ray diffraction. An order parameter near 50% and a maximum coercivity of 12 kOe were obtained with laser energy densities of 25-32 J/cm{sup 2}. Grain growth, quantified by dark field transmission electron microscopy, occurred during chemical ordering at the laser pulse widths studied.

  8. Dendritic growth and crystalline quality of nickel-base single grains

    Science.gov (United States)

    Siredey, Nathalie; Boufoussi, M'Bareck; Denis, Sabine; Lacaze, Jacques

    1993-05-01

    It is a usual observation that subgrains exist in nickel-base single grain components solidified by the lost wax process. The associated misorientations are generally small, but they can eventually lead to casting defects in the case of highly complex mold shapes. This work presents an attempt to relate the formation of subgrain boundaries with the development of the dendritic solidification microstructure. Experimental investigations have been undertaken on cast components made of AM1 nickel-base superalloy designed for high temperature turbine blades. Single grains were obtained by means of a grain selector at the bottom of each part. Metallographic observations have been made to characterize the dendritic array, together with gamma diffraction to measure the crystalline quality of the material and X-ray topography for mapping of misorientations on a dendritic scale. Small misorientations between dendrite stems have been found at the upper end of the selector which lead to the formation of subgrains. Moreover, during the growth process, the total mosaicity of the material increases, firstly as a consequence of an increase in the misorientations between subgrains, and secondly because of a decrease of the internal quality of each subgrain. It is proposed that misorientations are due to thermomechanical stresses which build up during λ' precipitation at temperatures slightly below the solidus temperature of the alloy.

  9. Dendritic growth and crystalline quality of nickel-base single grains

    Energy Technology Data Exchange (ETDEWEB)

    Siredey, N. (Lab. de Science et Genie des Materiaux Metalliques, Ecole des Mines, 54 - Nancy (France)); Boufoussi, M.B. (Lab. de Science et Genie des Materiaux Metalliques, Ecole des Mines, 54 - Nancy (France)); Denis, S. (Lab. de Science et Genie des Materiaux Metalliques, Ecole des Mines, 54 - Nancy (France)); Lacaze, J. (Lab. de Science et Genie des Materiaux Metalliques, Ecole des Mines, 54 - Nancy (France))

    1993-05-01

    It is a usual observation that subgrains exist in nickel-base single grain components solidified by the lost wax process. The association misorientations are generally small, but they can eventually lead to casting defects in the case of highly complex mold shapes. This work presents and attempt to relate the formation of subgrain boundaries with the development of the dendritic solidification microstructure. Experimental investigations have been undertaken on cast components made of AM1 nickel-base superalloy designed for high temperature turbine blades. Single grains were obtained by means of a grain selector at the bottom of each part. Metallographic observations have been made to characterize the dendritic array, together with gamma diffraction to measure the crystalline quality of the material and X-ray topography for mapping of misorientations on a dendritic scale. Small misorientations between dendrite stems have been found at the upper end of the selector which lead to the formation of subgrains. Moreover, during the growth process, the total mosaicity of the material increases, firstly as a consequence of an increase in the misorientations between subgrains, and secondly because of the decrease of the internal quality of each subgrain. It is proposed that misorientations are due to thermomechanical stresses which build up during [gamma]' precipitation at temperatures slightly below the solidus temperature of the alloy. (orig.)

  10. Pollen Grain Germination and Pollen Tube Growth in Pistil of Rice

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The germination of pollen grain in vitro and the growth of pollen tube in the pistil of rice were observed with a microscope.The stigma was removed at different time points after pollination to study its effect on seed setting rate.The rice pollen grain started to germinate at 2 min after pollination and the pollen tube penetrated stigma into style in 5-10 min,30 min later the end of pollen tube reached the bottom of ovary,and only some pollen tubes arrived at embryo sac at 40 min after pollination.Meanwhile,a small amount of catlose began to deposit in the pollen tubes,a great deal of callose was observed at 50 min after pollination,whereas the pollen grain began to shrink.The growing rates of pollen tube in the rice stigma,style and ovary were 1500,5000,and 5400 pm/h,respectively.The seed setting rate was quite low when the stigma was removed at about 10-15 min after pollination,gradually increased when it removed at 20 min to 50 min after pollination,and over 60%when it removed at 50 min after pollination and finally tended to be stable.

  11. CONSTRAINTS ON THE RADIAL VARIATION OF GRAIN GROWTH IN THE AS 209 CIRCUMSTELLAR DISK

    Energy Technology Data Exchange (ETDEWEB)

    Perez, Laura M.; Carpenter, John M.; Isella, Andrea; Ricci, Luca; Sargent, Anneila I. [Astronomy Department, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Chandler, Claire J. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Andrews, Sean M.; Harris, Robert J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Calvet, Nuria [Department of Astronomy, University of Michigan, 830 Dennison Building, 500 Church Street, Ann Arbor, MI 48109 (United States); Corder, Stuartt A. [Joint ALMA Observatory, Av. Alonso de Cordova 3107, Vitacura, Santiago (Chile); Deller, Adam T. [The Netherlands Institute for Radio Astronomy (ASTRON), 7990-AA Dwingeloo (Netherlands); Dullemond, Cornelis P.; Linz, Hendrik [Center for Astronomy, Heidelberg University, Albert Ueberle Str. 2, D-69120 Heidelberg (Germany); Greaves, Jane S. [School of Physics and Astronomy, University of St. Andrews, North Haugh, St Andrews KY16 9SS (United Kingdom); Henning, Thomas [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Kwon, Woojin [Department of Astronomy, University of Illinois, 1002 West Green Street, Urbana, IL 61801 (United States); Lazio, Joseph [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91106 (United States); Mundy, Lee G.; Storm, Shaye [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Testi, Leonardo [European Southern Observatory, Karl Schwarzschild Str. 2, D-85748 Garching (Germany); and others

    2012-11-20

    We present dust continuum observations of the protoplanetary disk surrounding the pre-main-sequence star AS 209, spanning more than an order of magnitude in wavelength from 0.88 to 9.8 mm. The disk was observed with subarcsecond angular resolution (0.''2-0.''5) to investigate radial variations in its dust properties. At longer wavelengths, the disk emission structure is notably more compact, providing model-independent evidence for changes in the grain properties across the disk. We find that physical models which reproduce the disk emission require a radial dependence of the dust opacity {kappa}{sub {nu}}. Assuming that the observed wavelength-dependent structure can be attributed to radial variations in the dust opacity spectral index ({beta}), we find that {beta}(R) increases from {beta} < 0.5 at {approx}20 AU to {beta} > 1.5 for R {approx}> 80 AU, inconsistent with a constant value of {beta} across the disk (at the 10{sigma} level). Furthermore, if radial variations of {kappa}{sub {nu}} are caused by particle growth, we find that the maximum size of the particle-size distribution (a{sub max}) increases from submillimeter-sized grains in the outer disk (R {approx}> 70 AU) to millimeter- and centimeter-sized grains in the inner disk regions (R {approx}< 70 AU). We compare our observational constraint on a{sub max}(R) with predictions from physical models of dust evolution in protoplanetary disks. For the dust composition and particle-size distribution investigated here, our observational constraints on a{sub max}(R) are consistent with models where the maximum grain size is limited by radial drift.

  12. The strategy of the wheat plant in acclimating growth and grain production to nitrogen availability.

    Science.gov (United States)

    Oscarson, P

    2000-11-01

    Two cultivars of spring wheat (Triticum aestivum L.) were grown to maturity in hydroponic cultures. Nitrogen accumulation was controlled by daily growth-limiting additions of nitrate together with all other nutrients in excess. Six different curves of N accumulation were used, with the same relative changes from day to day, but with different amplitudes. These curves were obtained by using the same mathematic formula of the N accumulation curves but varying the value of initial N content. The total amount of nitrogen added varied from 20 mg plant(-1) to 65 mg plant(-1). Plant bioproductivity showed a linear response to accumulated N. The number of grains per plant increased linearly with increased N availability whereas grain weights were essentially unaffected. Grain N concentrations and N content varied slightly, with highest values generally at the lower N availability levels. The quantitatively most important response to increased N availability was an increased number of earbearing tillers per plant. This varied from 0.1 tiller plant(-1) at maturity when given 20 mg N plant(-1), up to about 2 tillers plant(-1) when given 65 mg N plant(-1). Not all tillers that were initiated developed ears. The reduction of tillers seems to be one important mechanism in adapting plant productivity to N availability. Other individual characters influenced by N availability were straw height and the number of spikelets per spike. The two cultivars behaved in a qualitatively similar manner over the range of N availability even though they quantitatively differed in grain size, N concentrations and yield. PMID:11113170

  13. Increased Fetal Plasma Erythropoietin in Monochorionic Twin Pregnancies With Selective Intrauterine Growth Restriction and Abnormal Umbilical Artery Doppler.

    Science.gov (United States)

    Chang, Yao-Lung; Chao, An-Shine; Peng, Hsiu-Huei; Chang, Shuenn-Dyh; Su, Sheng-Yuan; Chen, Kuan-Ju; Cheng, Po-Jen; Wang, Tzu-Hao

    2016-08-01

    Hypoxia is the primary stimulus for the production of erythropoietin (EPO) in both fetal and adult life. Here, we investigated fetal plasma EPO concentrations in monochorionic (MC) twin pregnancies with selective intrauterine growth restriction (sIUGR) and abnormal umbilical artery (UA) Doppler. We diagnosed sIUGR in presence of (1) birth-weight discordance >20% and (2) either twin with a birth weight <10th percentile. An abnormal UA Doppler was defined as a persistent absent-reverse end diastolic flow (AREDF). The intertwin EPO ratio was calculated as the plasma EPO level of the smaller (or small-for-gestational-age) twin divided by the EPO concentration of the larger (or appropriate-for-gestational-age (AGA)) twin. Thirty-two MC twin pairs were included. Of these, 17 pairs were normal twins (Group 1), seven pairs were twins with sIUGR without UA Doppler abnormalities (Group 2), and eight pairs were twins with sIUGR and UA Doppler abnormalities (Group 3). The highest EPO ratio was identified in Group 3 (p < .001) but no significant differences were observed between Groups 1 and 2. Fetal hemoglobin levels did not differ significantly in the three groups, and fetal EPO concentration did not correlate with gestational age at birth. We conclude that fetal plasma EPO concentrations are selectively increased in MC twin pregnancies with sIUGR and abnormal UA Doppler, possibly as a result of uncompensated hypoxia. PMID:27161360

  14. Topological evolution during coupled grain growth and Ostwald ripening in volume-conserved 2-D two-phase polycrystals

    International Nuclear Information System (INIS)

    The topological evolution during coupled grain growth and Ostwald ripening in volume-conserved two-phase polycrystalline systems was studied in two dimensions (2-D), employing computer simulations based on a continuum diffuse-interface field model. The topological distributions were found to scale with time, but dependent on the ratios of grain boundary energies to the interphase boundary energy, the volume fractions and the initial microstructures. The correlations between topological class and grain size, as well as the topological correlations of grains with their neighbor grains were observed. The differences in topological features between volume-conserved two-phase systems and single-phase systems are discussed for ZrO2 and Al2O3 phases

  15. Using Soil Plant Analysis Development Chlorophyll Meter for Two Growth Stages to Assess Grain Yield of Malaysian Rice (Oryza sativa

    Directory of Open Access Journals (Sweden)

    Asa Gholizadeh

    2011-01-01

    Full Text Available Problem statement: Proper yield management in rice influences grain quality and quantity. Nitrogen site-specific management is also effective on final product of crops because excessive nitrogen application at any growth stage can reduce yield and increase disease incidence. In contrast, suboptimal nitrogen levels at discrete growth stages may substantially reduce plant productivity. The nitrogen status at specific growth stages may be used for estimating supplemental nitrogen requirements and yield potential. The SPAD chlorophyll meter is a quick and non-destructive tool used for directly measuring leaf chlorophyll and indirectly assessing the proportional parameter of leaf, plant nitrogen status and finally, grain yield. Approach: Describing within-field variability in a typical Malaysian paddy field was conducted to show the temporal variability of SPAD readings and also grain yield. Furthermore, the study aimed to introduce the rice growth stage which SPAD readings show higher relationship with grain yield. SPAD readings data was collected at two different growth stages (55 DAT and 80 DAT using a Minolta SPAD 502. Grain yield was then collected at the end of the season to compare results with SPAD values. Results: Analysis of variance, variogram and kriging were conducted to determine the variability of parameters and also their relationship. Conclusion: Variability maps of the aforementioned parameters were generated. Increasing of SPAD values with growth stage could be observed in this study. SPAD readings taken at 55 DAT had a better relationship to grain yield than those taken at 80 DAT; therefore assessment of grain yield status is better to be done at 55 DAT.

  16. EBSD coupled to SEM in situ annealing for assessing recrystallization and grain growth mechanisms in pure tantalum.

    Science.gov (United States)

    Kerisit, C; Logé, R E; Jacomet, S; Llorca, V; Bozzolo, N

    2013-06-01

    An in situ annealing stage has been developed in-house and integrated in the chamber of a Scanning Electron Microscope equipped with an Electron BackScattered Diffraction system. Based on the Joule effect, this device can reach the temperature of 1200°C at heating rates up to 100°C/s, avoiding microstructural evolutions during heating. A high-purity tantalum deformed sample has been annealed at variable temperature in the range 750°C-1030°C, and classical mechanisms of microstructural evolutions such as recrystallization and grain coarsening phenomena have been observed. Quantitative measurements of grain growth rates provide an estimate of the mean grain boundary mobility, which is consistent with the value estimated from physical parameters reported for that material. In situ annealing therefore appears to be suited for complementing bulk measurements at relatively high temperatures, in the context of recrystallization and grain growth in such a single-phase material. PMID:23521093

  17. EBSD coupled to SEM in situ annealing for assessing recrystallization and grain growth mechanisms in pure tantalum.

    Science.gov (United States)

    Kerisit, C; Logé, R E; Jacomet, S; Llorca, V; Bozzolo, N

    2013-06-01

    An in situ annealing stage has been developed in-house and integrated in the chamber of a Scanning Electron Microscope equipped with an Electron BackScattered Diffraction system. Based on the Joule effect, this device can reach the temperature of 1200°C at heating rates up to 100°C/s, avoiding microstructural evolutions during heating. A high-purity tantalum deformed sample has been annealed at variable temperature in the range 750°C-1030°C, and classical mechanisms of microstructural evolutions such as recrystallization and grain coarsening phenomena have been observed. Quantitative measurements of grain growth rates provide an estimate of the mean grain boundary mobility, which is consistent with the value estimated from physical parameters reported for that material. In situ annealing therefore appears to be suited for complementing bulk measurements at relatively high temperatures, in the context of recrystallization and grain growth in such a single-phase material.

  18. Effect of stress-induced grain growth during room temperature tensile deformation on ductility in nanocrystalline metals

    Indian Academy of Sciences (India)

    Weichang Xu; Pinqiang Dai; Xiaolei Wu

    2010-10-01

    In the present study defect-free nanocrystalline (nc) Ni–Co alloys with the Co content ranging from 2.4–59.3% (wt.%) were prepared by pulse electrodeposition. X-ray diffraction analysis shows that only a single face-centred cubic solid solution is formed for each alloy and that the grain size reduces monotonically with increasing Co content, which is consistent with transmission electron microscopy (TEM) observations. In the nc Ni–Co alloys, both the ultimate tensile strength and the elongation to failure increase as the Co content increases. The TEM observations reveal that stress-induced grain growth during tensile deformation is significantly suppressed for the nc Ni–Co alloys rich in Co in sharp contrast to those poor in Co. We believe that sufficient solutes could effectively pin grain boundaries making grain boundary motions (e.g. grain boundary migration and/or grain rotation) during deformation more difficult. Thus, stress-induced grain growth is greatly suppressed. At the same time, shear banding plasticity instability is correspondingly delayed leading to the enhanced ductility.

  19. Analysis of ferrite grain growth mechanisms during {gamma}-{alpha} transformation in a niobium alloyed steel using EBSD

    Energy Technology Data Exchange (ETDEWEB)

    Novillo, E. [CEIT and TECNUN, P Manuel de Lardizabal 15, 20018 Donostia-San Sebastian (Spain); Hernandez, D. [CEIT and TECNUN, P Manuel de Lardizabal 15, 20018 Donostia-San Sebastian (Spain); Gutierrez, I. [CEIT and TECNUN, P Manuel de Lardizabal 15, 20018 Donostia-San Sebastian (Spain)]. E-mail: igutierrez@ceit.es; Lopez, B. [CEIT and TECNUN, P Manuel de Lardizabal 15, 20018 Donostia-San Sebastian (Spain)

    2004-11-15

    The austenite to ferrite phase transformation was studied in a C-Mn-Nb steel after different hot deformation schedules, leading to deformed and recrystallized austenite. The mechanisms of nucleation and growth of ferrite grains were investigated by means of the electron back scattered diffraction (EBSD) technique. The ferrite microstructures were characterised in terms of the misorientation angles between ferrite grains and the deviations from an ideal Kurdjumov-Sachs orientation relationship with the austenite. The results show that the grain refinement produced by the accumulation of the deformation in the austenite is limited to a certain extent by the ferrite grain coarsening taking place behind the transformation front. Both coalescence and normal grain growth have been observed to contribute to this coarsening. Coalescence is enhanced as a result of the variant selection taking place in transformation from a recrystallized austenite. The accumulation of the deformation in the austenite results in ferrite-ferrite boundaries of higher misorientation, causing coalescence in this case to be less favoured, as compared with normal grain growth.

  20. Roles of plant growth regulators on yield, grain qualities and antioxidant enzyme activities in super hybrid rice (Oryza sativa L.)

    OpenAIRE

    Pan, Shenggang; Rasul, Fahd; Li, Wu; Tian, Hua; Mo, Zhaowen; Duan, Meiyang; Tang, Xiangru

    2013-01-01

    Background Plant growth regulators play important roles in plant growth and development, but little is known about roles of plant growth regulators in yield, grain qualities and antioxidant enzyme activities in super hybrid rice. In this study, gibberellic acid(GA3), paclobutrazol (PBZ), 6-Benzylaminopurine(6-BA) treatments and distilled water (control) were sprayed to two hybrid rice cultivars (Peizataifeng and Huayou 86) at the heading stage in the field experiments in both early and late s...

  1. Nanoscale Investigation of Grain Growth in RF-Sputtered Indium Tin Oxide Thin Films by Scanning Probe Microscopy

    Science.gov (United States)

    Lamsal, B. S.; Dubey, M.; Swaminathan, V.; Huh, Y.; Galipeau, D.; Qiao, Q.; Fan, Q. H.

    2014-11-01

    This work studied the electronic characteristics of the grains and grain boundaries of indium tin oxide (ITO) thin films using electrostatic and Kelvin probe force microscopy. Two types of ITO films were compared, deposited using radiofrequency magnetron sputtering in pure argon or 99% argon + 1% oxygen, respectively. The average grain size and surface roughness increased with substrate temperature for the films deposited in pure argon. With the addition of 1% oxygen, the increase in the grain size was inhibited above 150°C, which was suggested to be due to passivation of the grains by the excess oxygen. Electrostatic force microscopy and Kelvin probe force microscopy (KPFM) images confirmed that the grain growth was defect mediated and occurred at defective interfaces at high temperatures. Films deposited at room temperature with 1% oxygen showed crystalline nature, while films deposited with pure argon at room temperature were amorphous as observed from KPFM images. The potential drop across the grain and grain boundary was determined by taking surface potential line profiles to evaluate the electronic properties.

  2. Effects of oxide coating on the growth of single grain YBCO bulk superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.D.; Jun, B.-H. [Neutron Science Division, Korea Atomic Energy Research Institute (KAERI), Daejeon 305-353 (Korea, Republic of); Park, B.J.; Jung, S.Y. [Superconductivity and Applications Group, Korea Electric Power Research Institute (KEPRI), Daejeon 305-380 (Korea, Republic of); Seong, B.S. [Neutron Science Division, Korea Atomic Energy Research Institute (KAERI), Daejeon 305-353 (Korea, Republic of); Kim, C.-J., E-mail: cjkim2@kaeri.re.k [Neutron Science Division, Korea Atomic Energy Research Institute (KAERI), Daejeon 305-353 (Korea, Republic of)

    2009-10-15

    Surface oxide coating and bottom inserting of oxide plates have been conducted to top seeded melt growth (TSMG) processed YBa{sub 2}Cu{sub 3}O{sub 7-y} (Y123) bulk superconductors with an aim of controlling the Y123 nucleation and growth. The coating medium for surfaces was Yb{sub 2}O{sub 3} solution and the bottom inserts were Yb{sub 2}O{sub 3}/Y{sub 2}O{sub 3} powder compact. Many vertical cracks were found to develop at the compact/insert interfaces when an Yb{sub 2}O{sub 3} insert was used, but the crack evolution was greatly reduced when a (Yb{sub 2}O{sub 3} + Y{sub 2}O{sub 3}) insert was used. The formation of the vertical cracks is ascribed to the difference in thermal expansion between the YBCO compact and bottom insert. Presence of vertical cracks was found to be crucial to the trapped magnetic field and levitation forces of single grain YBCO bulk superconductors. The Y123 nucleation and growth in TSMG-processed YBCO bulk superconductors were successfully controlled by conducting surface coating and bottom plating using a (Yb{sub 2}O{sub 3} + Y{sub 2}O{sub 3}) insert and as a result, the levitation properties were much enhanced.

  3. Texture development in Al-high Mg alloys during recrystallization and grain growth

    Energy Technology Data Exchange (ETDEWEB)

    Endou, S.; Inagaki, H. [Shonan Inst. of Tech., Fujisawashi (Japan)

    2001-07-01

    Al-high Mg alloys containing Mg more than 6% were cold rolled 95% and annealed at temperatures between 275 and 450 C. Textures developed in these alloys were investigated with the orientation distribution function analysis. It was found that the heating rate to the annealing temperature strongly influenced the annealing textures of these alloys. Annealing with the slow heating rate resulted in the development of {l_brace}100{r_brace} left angle 001 right angle, whereas annealing with the rapid heating rate enhanced the development of {l_brace}100{r_brace} left angle 013 right angle and {l_brace}103{r_brace} left angle 321 right angle. This is because the orientation distribution established at complete recrystallization had strong influences on the texture development during subsequent grain growth. Annealing textures in the Al-9% Mg alloy were always random, since its rolling textures were random (orig.)

  4. Effects of Nitrogen Application in Different Wheat Growth Stages on the Floret Development and Grain Yield of Winter Wheat

    Institute of Scientific and Technical Information of China (English)

    ZHU Yun-ji; WANG Chen-yang; GUO Tian-cai; CUI Jin-mei; XIA Guo-jun; LIU Wan-dai; WANG Yong-hua

    2002-01-01

    The study was carried out on the effect of nitrogen application in different wheat growth stage on the floret development, the photosynthetic rate, the yield and its components of winter wheat. The result indicated that nitrogen application in the pistil-stamen primordium formation stage and the tetrad formation stage of wheat growth prolonged the duration of floret development, promoted the balance growth of floret and reduced the floret decadence number, thus increased the grain number per spike. Nitrogen application in the middle and in the late stages of wheat development increased the photosynthetic ability of the plant leaves in the later stage, and also lengthened the peak of grain filling stage, thus enhanced the grain weight and yield of wheat significantly.

  5. The role of gallium sulfide in SrS:Ce grain growth

    Energy Technology Data Exchange (ETDEWEB)

    Evans, N.D. [Oak Ridge Inst. for Science and Education, TN (United States); Naman, A.; Jones, K.S.; Holloway, P.H. [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering; Rice, P.M. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1997-04-01

    Whereas efficient red (ZnS:Mn) and green (ZnS:Tb) phosphors are available for full-color flat-panel display technology, efficient blue phosphors are still under development. SrS:Ce is being investigated as a suitable material. As part of a larger study, annealed SrS:Ce films produced from sputter targets incorporating Ga{sub 2}S{sub 3} were found to be five times brighter than films produced from targets containing no Ga{sub 2}S{sub 3}. Consequently, the significance of added gallium sulfide to the morphology of SrS:Ce films during annealing is being investigated. Following deposition, plan view specimens of films were prepared for transmission electron microscopy by mechanical grinding, dimpling, and Ar{sup +} milling. Films were examined in a Philips CM12, and a JEOL 200CX. Additionally, EDS line scans were obtained in the scanning-transmission mode of a Philips CM200FEG, integrated with an EMiSPEC Vision acquisition system. The EDS line scans were defined as a series of 40 points along a line, spaced approximately 3.6 nm apart. The dwell time for EDS acquisition at each point was 10 sec. It was found that the addition of Ga{sub 2}S{sub 3} increases the brightness of SrS:Ce films by enhancing grain growth during annealing. Also being investigated is the possibility that Ga{sub 2}S{sub 3}, either as a sub-sulfide or as a source of Ga, is involved in a liquid-phase sintering mechanism, which would account for the increased grain growth observed after annealing.

  6. Abnormal growth of the corticospinal axons into the lumbar spinal cord of the hyt/hyt mouse with congenital hypothyroidism.

    Science.gov (United States)

    Hsu, Jung-Yu C; Stein, Stuart A; Xu, Xiao-Ming

    2008-11-01

    Thyroid hormone deficiency may cause severe neurological disorders resulting from developmental deficits of the central nervous system. The mutant hyt/hyt mouse, characterized by fetal-onset, life-long hypothyroidism resulting from a point mutation of the thyroid-stimulating hormone receptor of the thyroid gland, displays a variety of abnormalities in motor behavior that are likely associated with dysfunctions of specific brain regions and a defective corticospinal tract (CST). To test the hypothesis that fetal and neonatal hypothyroidism cause abnormal CST development, the growth of the CST was investigated in hypothyroid hyt/hyt mice and their euthyroid progenitors, the BALB/cByJ mice. Anterograde labeling with biotinylated dextran amine demonstrated a decrease in the number of CST axons in the hyt/hyt mouse at the first lumbar level at postnatal day (P) 10. After retrograde tracing with fast blue (FB), fewer FB-labeled neurons were found in the motor cortex, the red nucleus, and the lateral vestibular nucleus of the hyt/hyt mouse. At the fourth lumbar level, the hyt/hyt mouse also showed smaller CST cross-sectional areas and significantly lower numbers of unmyelinated axons, myelinated axons, and growth cones within the CST during postnatal development. At P10, the hyt/hyt mouse demonstrated significantly lower immunoreactivity of embryonic neural cell adhesion molecule in the CST at the seventh cervical level, whereas the expression of growth-associated protein 43 remained unchanged. Our study demonstrated an abnormal development of the CST in the hyt/hyt mouse, manifested by reduced axon quantity and retarded growth pattern at the lumbar spinal cord. PMID:18543337

  7. Effects of Grain Boundaries and Dislocation Cell Walls on Void Nucleation and Growth in Aluminium during Fast Neutron Irradiation

    DEFF Research Database (Denmark)

    Horsewell, Andy; Rahman, F. A.; Singh, Bachu Narain

    1983-01-01

    High purity aluminium irradiated to fluences between 2 multiplied by 10**2**1 and 1 multiplied by 10**2**4 n. m** minus **2 (E greater than 1 Mev) at 120 degree C has been investigated by TEM. A void denuded zone is seen both at grain boundaries and dislocation cell walls. Enhanced void formation...... and growth occurs in a zone extending up to 10 mu m from grain boundaries in annealed material. In polygonized material, the presence of dislocation cell walls leads to cell size dependent void formation and growth; the swelling rate in the large cells is substantially higher than in the annealed material....

  8. Aging Precursor Solution in High Humidity Remarkably Promoted Grain Growth in Cu₂ZnSnS₄ Films.

    Science.gov (United States)

    Guan, Zhongjie; Luo, Wenjun; Xu, Yao; Tao, Qiuchen; Wen, Xin; Zou, Zhigang

    2016-03-01

    Earth-abundant Cu2ZnSnS4 (CZTS) is a promising material for thin film solar cells or solar water splitting cells. Generally, large grain size and vertical penetration are highly desirable microstructures to high-efficiency solar conversion devices. Up to date, some kinds of vacuum methods have been used to prepare large grain-sized CZTS, which are expensive and limit their applications on a large scale. It is still a key challenge to prepare large-grained and vertical-penetration CZTS by a low-cost solution method. In this study, we obtained vertical-penetration CZTS thin film with 1.3 μm grain sizes by a faclie solution method. Different from previous studies, precursor solution was aged in high-humidity air before it was used to prepare CZTS films. The grain size prepared with aging precursor solution was one of the largest among the samples prepared by a solution method after sulfurizing. Moreover, the large-grained CZTS films were used as photocathodes for solar water splitting, which exhibited a much higher photocurrent than those of the samples without aging. To the best of our knowledge, this is the first demonstration to promote grain growth in CZTS by aging precursor solution in high-humidity air. This aging method can offer a reference to prepare other high-performance films. PMID:26863181

  9. Screening effect during the growth of spheroidal grains vs deviations from Kolmogorov- Johnson-Mehl-Avrami equation

    Directory of Open Access Journals (Sweden)

    A. A. Burbelko

    2008-03-01

    Full Text Available To forccast rhc kinc~icso f phasc transformations which consist in nucleation and growth of rhc grains of a ncw phnsc, rhc wcll-knownKolmogorov-lohson-Mchl-Avrami (KJM A equation has becn used. It is gencr;llly known that in lhc case of pnrsllcl gr;cin prowlh indiffcrcnt phascs proceeding at difrcrcnl vclocirics. tbc rcsulis OF thc ralcularions arc burdcncd with an crror. 111 this study. applying rhcassumpfions of n stnist ical thcory or thc scrccncd grain growlh. an attcrnpt has bccn madc to cstimatc this crror ror thc casc or prowl11 ofthc sphcroidnl grains of two rypcs. Thc ohiaincd rcsulls indicate that thc vatuc of an crror in typical equations incrcsscs with iacrcasingdilrfercncc in the growth vclocity of thc particlcs of bath typcs.

  10. Controlled grain growth in granular FePt-SiO{sub 2} thin films under single pulsed laser anneals

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, Y. [Center for Materials and Information Technology, The University of Alabama, Tuscaloosa, AL 35487 (United States); Klemmer, T.J.; Kubota, Y. [Seagate Technologies, Fremont, CA 94536 (United States); Harrell, J.W. [Department of Physics and Astronomy, The University of Alabama, Tuscaloosa, AL 35487 (United States); Thompson, G.B., E-mail: gthompson@eng.ua.edu [Department of Metallurgical and Materials Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States)

    2012-12-01

    The high magnetocrystalline phase of L1{sub 0} FePt has received considerable attention for achieving stable magnetization states in small volumes which could increase magnetic areal storage densities. When FePt is sputter-deposited, it adopts a magnetically soft A1 phase requiring annealing to phase transform to the L1{sub 0} phase; this annealing results in detrimental grain growth which reduces the capacity for high areal storage densities. In the current work, a series of 10 nm thick granular FePt-SiO{sub 2} thin films with various silica contents has been annealed at different fluences using a 10 ms pulse width, 1064 nm wavelength laser to determine if the silica matrix could inhibit this grain growth. The A1 to L1{sub 0} phase transformation was confirmed by selected area electron diffraction. In general, the films annealed with approximately 25 J/cm{sup 2} exhibited the highest L1{sub 0} c/a tetragonality, 0.97, and coercivity of approximately 875 kA/m (11 kOe). For these films, the 38 vol.% silica incorporation resulted in a FePt grain size of approximately 8.5 nm as compared to 30 nm for films with no silica. The granular encasement of the FePt grains was effective at reducing but unable at inhibiting grain growth using single pulsed laser anneals. - Highlights: Black-Right-Pointing-Pointer Grain growth was hindered by laser annealing in a granular matrix. Black-Right-Pointing-Pointer Laser annealing allowed the preservation of the granular microstructure. Black-Right-Pointing-Pointer Fluences exceeding 25 J/cm{sup 2} resulted in microstructure breakdown.

  11. Drought priming at vegetative growth stages improves tolerance to drought and heat stresses occurring during grain filling in spring wheat

    DEFF Research Database (Denmark)

    Wang, Xiao; Vignjevic, Marija; Liu, Fulai;

    2015-01-01

    Plants of spring wheat (Triticum aestivum L. cv. Vinjett) were exposed to moderate water deficit at the vegetative growth stages six-leaf and/or stem elongation to investigate drought priming effects on tolerance to drought and heat stress events occurring during the grain filling stage. Compared...

  12. Analytical expression for the evolution of interfacial area density between transformed grains during nucleation and growth transformations

    DEFF Research Database (Denmark)

    Rios, P.R.; Godiksen, R.B.; Schmidt, Søren;

    2006-01-01

    This paper shows that interfacial area density between transformed grains during nucleation and growth transformations and the contiguity are useful descriptors of microstructural evolution. These descriptors are evaluated analytically and compared with results from computer simulation. Usage of ...... of these descriptors makes microstructural path analysis even more reliable and robust. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved....

  13. Effect of γ radiation processing on fungal growth and quality characteristcs of millet grains.

    Science.gov (United States)

    Mahmoud, Nagat S; Awad, Sahar H; Madani, Rayan M A; Osman, Fahmi A; Elmamoun, Khalid; Hassan, Amro B

    2016-05-01

    The aim of this study was to evaluate the effect of gamma radiation processing of millet grains on fungal incidence, germination, free fatty acids content, protein solubility, digestible protein, and antinutritional factors (tannin and phytic acid). The grains were exposed to gamma radiation at doses 0.25, 0.5, 0.75, 1.0, and 2.0 kGy. Obtained results revealed that radiation of millet grains at a dose level higher than 0.5 kGy caused significant (P phytic acid content and gradual increment on in vitro protein digestibility of the grains. On the other hand, the treatments significantly (P < 0.05) increased the protein solubility of the grains. Obtained results indicate that gamma irradiation might improve the quality characteristics of millet grains, and can be used as a postharvest method for disinfestations and decontamination of millet grains. PMID:27247763

  14. Studies of "reactive templated grain growth" in some complex-oxide perovskites

    Science.gov (United States)

    West, David Lawrence

    This thesis details research on "reactive-templated grain growth" (RTGG) processing of complex-oxide perovskites. Four independent yet interwoven investigations are described. In the first, molten-salt synthesis yielded plate-like (˜0.2 x 5 x 5 mum) Ruddlesden-Popper (Sr3Ti 2O7) and Aurivillius (Bi4Ti3O 12 (BiT) and BaBi2Nb2O9) phases which served as "templates" in the subsequent studies. "Chemical preparation" routes were designed to produce intimately mixed, fine-grain matrix powders for the second and third investigations. A "citrate gel" method was developed for Bi1/2Na 1/2TiO3 (BNT)-based powders and a "sequential precipitation" method for PbNi1/3Nb2/3O3 - PbTiO3 (PNNT)-based powders. Both methods were original to the present investigation and resulted in dense, mum to sub-mum scale microstructures when applied to un-templated compositions. Microstructure studies of templated, chemically-prepared mixtures indicated that both Aurivillius phases behaved similarly with BNT-based matrices: An initially heterogeneous microstructure evolved towards a dense assemblage of anisometric (˜1 x 5 x 5 mum) grains. Sr3Ti 2O7 exhibited consistent behavior with both BNT and PNNT-based matrices: The microstructure evolved towards an aggregation of equi-axed, mum-scale grains with larger, isolated pores. A qualitative model was proposed to account for the behavior. It considered the excess matrix constituents after reaction to ABO3 perovskite and predicted an A-excess matrix in BNT-based mixtures templated with the Aurivillius phases and a B-excess matrix in BNT-based mixtures templated with Sr3Ti2O7. Predictions for PNNT-based matrices were less definite but not contradictory. In the final phase of the investigation, the solids formulation for BiT-templated, RTGG-processed Bi1/2Na17/40K3/40TiO 3 (BNKT) was systematically varied. This approach, original to this thesis, involved pre-reacting to well-defined alkali and bismuth titanate precursors. Use of these in different BNKT

  15. Spinal muscular atrophy astrocytes exhibit abnormal calcium regulation and reduced growth factor production.

    Science.gov (United States)

    McGivern, Jered V; Patitucci, Teresa N; Nord, Joshua A; Barabas, Marie-Elizabeth A; Stucky, Cheryl L; Ebert, Allison D

    2013-09-01

    Spinal muscular atrophy (SMA) is a genetic disorder caused by the deletion of the survival motor neuron 1 (SMN1) gene that leads to loss of motor neurons in the spinal cord. Although motor neurons are selectively lost during SMA pathology, selective replacement of SMN in motor neurons does not lead to full rescue in mouse models. Due to the ubiquitous expression of SMN, it is likely that other cell types besides motor neurons are affected by its disruption and therefore may contribute to disease pathology. Here we show that astrocytes in SMAΔ7 mouse spinal cord and from SMA-induced pluripotent stem cells exhibit morphological and cellular changes indicative of activation before overt motor neuron loss. Furthermore, our in vitro studies show mis-regulation of basal calcium and decreased response to adenosine triphosphate stimulation indicating abnormal astrocyte function. Together, for the first time, these data show early disruptions in astrocytes that may contribute to SMA disease pathology. PMID:23839956

  16. Dust grain growth in the interstellar medium of galaxies at redshifts 4

    CERN Document Server

    Michałowski, Michał J; Hjorth, Jens; Watson, Darach; Gall, Christa; Dunlop, James S

    2011-01-01

    To discriminate between different dust formation processes is a key issue in order to understand its properties. We analysed six submillimeter galaxies at redshifts 4grain growth in the interstellar medium is responsible for bulk of the dust mass accumulation in these galaxies.

  17. Spectroscopic infrared extinction mapping as a probe of grain growth in IRDCs

    CERN Document Server

    Lim, Wanggi; Tan, Jonathan C

    2015-01-01

    We present spectroscopic tests of MIR to FIR extinction laws in IRDC G028.36+00.07, a potential site of massive star and star cluster formation. Lim & Tan (2014) developed methods of FIR extinction mapping of this source using ${\\it Spitzer}$-MIPS ${\\rm 24\\mu m}$ and ${\\it Herschel}$-PACS ${\\rm 70\\mu m}$ images, and by comparing to MIR ${\\it Spitzer}$-IRAC $3$--${\\rm 8\\mu m}$ extinction maps, found tentative evidence for grain growth in the highest mass surface density regions. Here we present results of spectroscopic infrared extinction (SIREX) mapping using ${\\it Spitzer}$-IRS (14 to ${\\rm 38\\mu m}$) data of the same IRDC. These methods allow us to first measure the SED of the diffuse Galactic ISM that is in the foreground of the IRDC. We then carry out our primary investigation of measuring the MIR to FIR opacity law and searching for potential variations as a function of mass surface density within the IRDC. We find relatively flat, featureless MIR-FIR opacity laws that lack the $\\sim{\\rm 12\\mu m}$ an...

  18. Abnormal growth patterns in the sea urchin Tripneustes cf. gratilla (l. ) under pollution (Echinodermata, Echinoidea)

    Energy Technology Data Exchange (ETDEWEB)

    Dafni, J.

    1980-10-07

    Two populations of deformed sea-urchins were found near a combined power and desalination plant in the Gulf of Eilat, Red Sea. This area is highly polluted by thermohaline and heavy metal ion effluents. More than 60% of the urchins showed irregular bulging of the aboral half of the test. The height to diameter ratio for the most affected population was 0.70, compared with 0.53 for a normal population. The deformed sea-urchins had a wider peristome aperture and larger Aristotle's lantern, and fewer interambulacral plants than normal urchins of the same diameter. Growth rate of highly deformed urchins was very low. Growth lines in the deformed urchins' plates indicate excessive growth in the meridional direction. Some possible controlling mechanisms are suggested. (4 graphs, 1 map, 11 photos, 32 references, 3 tables)

  19. Screening effect during the growth of spheroidal grains vs deviations from Kolmogorov- Johnson-Mehl-Avrami equation

    OpenAIRE

    A.A. Burbelko

    2008-01-01

    To forccast rhc kinc~icso f phasc transformations which consist in nucleation and growth of rhc grains of a ncw phnsc, rhc wcll-knownKolmogorov-lohson-Mchl-Avrami (KJM A) equation has becn used. It is gencr;llly known that in lhc case of pnrsllcl gr;cin prowlh indiffcrcnt phascs proceeding at difrcrcnl vclocirics. tbc rcsulis OF thc ralcularions arc burdcncd with an crror. 111 this study. applying rhcassumpfions of n stnist ical thcory or thc scrccncd grain growlh. an attcrnpt has bccn madc t...

  20. Effect of Plant Essential Oils and Gamma Irradiation on Growth and Aflatoxin Production by Aspergillus Flavus Isolated from Wheat Grains

    International Nuclear Information System (INIS)

    The antifungal potential of essential oils of Thyme (Thymus vulgaris L.) and camphor ( Eucalyptus rostrata L.) was determined on Aspergillus flavus link isolated from wheat grains on Potato dextrose agar (PDA). They inhibited completely mycelia growth of the fungus at 1000 and 2000 ppm, and prevented aflatoxin production at sub lethal dose 500 and 1000 ppm respectively. Gamma radiation was used to control mycelia growth of Aspergillus flavus Link and inhibiting aflatoxin production. A dose level of 3.5 KGy gamma radiation prevented the fungal growth and aflatoxin production by A. flavus link, where a dose of 2.5 K Gy ( the sub lethal dose) prevented about 85% of aflatoxin production

  1. Abnormal Polyamine Metabolism in Hereditary Muscular Dystrophies: EFFECT OF HUMAN GROWTH HORMONE

    OpenAIRE

    Rudman, Daniel; Kutner, Michael H.; Chawla, Rajender K.; Goldsmith, Martin A.

    1980-01-01

    Previous studies showed hyperre-sponsiveness to human growth hormone (hGH) in men with myotonic or limb girdle dystrophies (MMD or LGD). Because polyamines may mediate some actions of hGH, we have now investigated polyamine metabolism in these and other dystrophies.

  2. Abnormal cortical development after premature birth shown by altered allometric scaling of brain growth.

    Directory of Open Access Journals (Sweden)

    Olga Kapellou

    2006-08-01

    Full Text Available BACKGROUND: We postulated that during ontogenesis cortical surface area and cerebral volume are related by a scaling law whose exponent gives a quantitative measure of cortical development. We used this approach to investigate the hypothesis that premature termination of the intrauterine environment by preterm birth reduces cortical development in a dose-dependent manner, providing a neural substrate for functional impairment. METHODS AND FINDINGS: We analyzed 274 magnetic resonance images that recorded brain growth from 23 to 48 wk of gestation in 113 extremely preterm infants born at 22 to 29 wk of gestation, 63 of whom underwent neurodevelopmental assessment at a median age of 2 y. Cortical surface area was related to cerebral volume by a scaling law with an exponent of 1.29 (95% confidence interval, 1.25-1.33, which was proportional to later neurodevelopmental impairment. Increasing prematurity and male gender were associated with a lower scaling exponent (p < 0.0001 independent of intrauterine or postnatal somatic growth. CONCLUSIONS: Human brain growth obeys an allometric scaling relation that is disrupted by preterm birth in a dose-dependent, sexually dimorphic fashion that directly parallels the incidence of neurodevelopmental impairments in preterm infants. This result focuses attention on brain growth and cortical development during the weeks following preterm delivery as a neural substrate for neurodevelopmental impairment after premature delivery.

  3. The Impact of Abnormal Glucose Tolerance and Obesity on Fetal Growth

    Directory of Open Access Journals (Sweden)

    Erin Graves

    2015-01-01

    Full Text Available Objective. Factors linked with insulin resistance were examined for their association with large-for-gestational-age (LGA infant birth weight and gestational diabetes. Study Design. Data came from a longitudinal cohort study of 2,305 subjects without overt diabetes, analyzed using multinomial logistic and linear regression. Results. High maternal BMI (OR=1.53 (1.11, 2.12, height (1.98 (1.62, 2.42, antidepressant use (1.71 (1.20, 2.44, pregnancy weight-gain exceeding 40 pounds (1.79 (1.25, 2.57, and high blood sugar (2.68, (1.53, 5.27 were all positively associated with LGA birth. Strikingly, the difference in risk from diagnosed and treated gestational diabetes compared to women with a single abnormal glucose tolerance test (but no diagnosis of gestational diabetes was significant (OR=0.65, p=0.12 versus OR=2.84, p<0.01. When weight/length ratio was used instead, different factors were found to be significant. BMI and pregnancy weight-gain were found to influence the development of gestational diabetes, through an additive interaction. Conclusions. High prepregnancy BM, height, antidepressant use, pregnancy weight-gain exceeding 40 pounds, and high blood sugar were associated with LGA birth, but not necessarily infant weight/length ratio. An additive interaction between BMI and pregnancy weight-gain influenced gestational diabetes development.

  4. Two-dimensional phase-field study of competitive grain growth during directional solidification of polycrystalline binary alloy

    Science.gov (United States)

    Takaki, Tomohiro; Ohno, Munekazu; Shibuta, Yasushi; Sakane, Shinji; Shimokawabe, Takashi; Aoki, Takayuki

    2016-05-01

    Selections of growing crystals during directional solidification of a polycrystalline binary alloy were numerically investigated using two-dimensional phase-field simulations. To accelerate the simulations, parallel graphics processing unit (GPU) simulations were performed using the GPU-rich supercomputer TSUBAME2.5 at the Tokyo Institute of Technology. Twenty simulations with a combination of five sets of different seed orientation distributions and four different temperature gradients covering dendritic and cellular growth regions were performed. The unusual grain selection phenomenon, in which the unfavorably oriented grains preferentially grow instead of the favorably oriented grains, was observed frequently. The unusual selection was more remarkable in the cellular structure than in the dendritic structure.

  5. Prospect for vaginal delivery of growth restricted fetuses with abnormal umbilical artery blood flow.

    OpenAIRE

    Li, Hui; Gudmundsson, Saemundur; Olofsson, Per

    2003-01-01

    Background. The best mode of delivery in cases of intrauterine growth restriction (IUGR) with umbilical artery blood flow changes is not well elucidated. Objective. To evaluate outcome in IUGR with umbilical artery blood flow changes planned for vaginal delivery after a negative oxytocin challenge test (OCT). Methods. In 84 term singleton pregnancies with suspected IUGR and no unanimous indication for abdominal delivery, Doppler velocimetry and OCT were performed. Positive OCT c...

  6. Melt growth of CdTe crystals and transmission electron microscopic investigations of their grain boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Sabinina, I.V.; Gutakovski, A.K.; Milenov, T.I.; Lyakh, N.N.; Sidorov, Y.G.; Gospodinov, M.M. (Inst. of Semiconductor Physics, Academy of Sciences of the USSR (Siberian Branch), Novosibirsk (USSR) Inst. of Solid State Physics, Bulgarian Academy of Sciences, Sofia (Bulgaria))

    1991-01-01

    Transmission electron microscopy investigations are carried out on CdTe crystals grown in quartz ampoules in a temperature region (1020-1091degC) near to the melting point of 1092degC, by travelling heater method in quasi-closed and in sealed (at 0.135 Pa) volume, and by the Bridgman method from nearly stoichiometric melts. An original method for preparation of CdTe thin foil is reported. Two types of grain boundaries are observed: high-angle misoriented grain boundaries (more than ten degrees misorientation between adjacent grains) and low-angle misoriented grain boundaries (less than one degree misorientation between adjacent sub-grain). Both dislocations with Burgers vector b=a/6<112> and b=a/2<110> are present. (orig.).

  7. Grain Growth Orientation and Anisotropy in Cu6Sn5 Intermetallic: Nanoindentation and Electron Backscatter Diffraction Analysis

    Science.gov (United States)

    Choudhury, Soud Farhan; Ladani, Leila

    2014-04-01

    As the size of joints in micro/nano-electronics diminishes, the role of intermetallic (IMC) layers becomes more significant. It was shown that solder joint strength is controlled largely by IMC strength at higher strain rates. Additionally, there is a possibility that very small joints are completely composed of IMCs. Further miniaturization of joints may result in statistical grain size effects. Therefore, it is essential to characterize IMC materials and understand their anisotropic mechanical properties. One of the most common types of IMCs in microelectronic joints is Cu6Sn5, which is formed in a variety of bonding materials with different compositions of Sn, Cu, and Ag. This work studies through nanoindentation elastic-plastic properties of a single grain of Cu6Sn5 IMC in a Sn-3.5Ag/Cu system with reflow soldering. Elastic properties such as elastic modulus and hardness were determined from the nanoindentation load-depth curve. The reverse analysis model described by Dao et al. was used to extract plastic properties such as yield strength and strain hardening exponent from nanoindentation data. Care was taken to achieve indentation of single grains with sufficient accuracy and repeatability. Electron backscatter diffraction (EBSD) mapping was used to determine orientation of Cu6Sn5 grains and to relate the orientation with the load-depth curve results of nanoindentation and the corresponding elastic and plastic properties. The EBSD results indicated that the Cu6Sn5 crystal structure is hexagonal. Columnar growth of the Cu6Sn5 grains was observed as the grains mostly grew along the c-axis of the crystal. Indentation of different grains parallel to the basal plane showed no significant difference in mechanical properties.

  8. Supernova dust formation and the grain growth in the early universe: The critical metallicity for low-mass star formation

    CERN Document Server

    Chiaki, Gen; Nozawa, Takaya; Yoshida, Naoki; Schneider, Raffaella; Omukai, Kazuyuki; Limongi, Marco; Chieffi, Alessandro

    2014-01-01

    We investigate the condition for the formation of low-mass second-generation stars in the early universe. It has been proposed that gas cooling by dust thermal emission can trigger fragmentation of a low-metallicity star-forming gas cloud. In order to determine the critical condition in which dust cooling induces the formation of low-mass stars, we follow the thermal evolution of a collapsing cloud by a one-zone semi-analytic collapse model. Earlier studies assume the dust amount in the local universe, where all refractory elements are depleted onto grains, and/or assume the constant dust amount during gas collapse. In this paper, we employ the models of dust formation and destruction in early supernovae to derive the realistic dust compositions and size distributions for multiple species as the initial conditions of our collapse calculations. We also follow accretion of heavy elements in the gas phase onto dust grains, i.e., grain growth, during gas contraction. We find that grain growth well alters the frag...

  9. Computer simulation of grain growth of intermediate--and final-stage sintering and Ostwald ripening of BaTiO3-based PTCR ceramics

    International Nuclear Information System (INIS)

    This paper presented a novel modified Q-states Potts Monte-Carlo computer simulation procedure applied to simulate the grain growth of intermediate and final stages of sintering and Ostwald ripening process of BaTiO3 Positive Temperature Coefficient of Resistance (PTCR) ceramics, and the effects of liquid-phases on the grain growth of BaTiO3-based PTCR ceramics. The computer simulating models of the grain growth of the sintering process were established by the theory of the grain growth. The simulating results indicated that (1) the liquid-phase would hinder the motion of the grain-boundary, and the ratio of the grain growth was limited so that the size of the grains was smaller than those of the single-phase system; (2) the shrinkage of a BaTiO3 PTCR ceramics almost ceased at the temperature of 1513 K or so in the two-phase system, and the soaking stage involved the densification and grain growth of ceramics controlled by liquid-phases

  10. Abnormal bone collagen morphology and decreased bone strength in growth hormone-deficient rats

    DEFF Research Database (Denmark)

    Lange, Martin; Qvortrup, Klaus; Svendsen, Ole Lander;

    2004-01-01

    rats as compared to their controls (P rats with isolated GHD. Whether similar conditions are present in GHD patients need further investigations. The changes described, however, may provide...... collagen morphology and bone mineralisation in cortical bone as well as bone strength in GHD rats to try to clarify the explanation for the increased fracture rate. The Dw-4 rat was used as a model for GHD. This strain of rats has an autosomal recessive disorder, reducing GH synthesis to approximately 10......% and growth rate to approximately 40-50% when compared to normal control rats. Five male Dw-4 rats were examined at age 12 weeks and five healthy Lewis rats served as age-matched controls. The animals were examined for (1) bone mineral status by dual energy X-ray absorptometry (DXA) and ash weight/bone volume...

  11. Analysis Of The Austenite Grain Growth In Low-Alloy Boron Steel With High Resistance To Abrasive Wear

    Directory of Open Access Journals (Sweden)

    Białobrzeska B.

    2015-09-01

    Full Text Available Today low-alloy steels with boron achieve high resistance to abrasive wear and high strength. These features are obtained by using advanced technology of manufacturing. This makes boron steels increasingly popular and their application more diverse. Application of these steels can extend the lifetime of very expensive machine construction in many industries such as mining, the automotive, and agriculture industries. An interesting subgroup of these materials is steel with boron intended for heat treatment. These steels are supplied by the manufacturer after cold or hot rolling so that it is possible for them to be heat treated in a suitable manner by the purchaser for its specific application. Very important factor that determines the mechanical properties of final product is austenite grain growth occurring during hot working process such us quenching or hot rolling. Investigation of the effect of heating temperature and holding time on the austenite grain size is necessary to understand the growth behavior under different conditions. This article presents the result of investigation of austenite grain growth in selected low-allow boron steel with high resistance to abrasive wear and attempts to describe the influence of chemical composition on this process.

  12. Kinetics of heterogeneous nucleation and growth: An approach based on a grain explicit model

    OpenAIRE

    Rouet-Leduc, Bertrand; Maillet, Jean-Bernard; Denoual, Christophe

    2013-01-01

    A model for phase transitions initiated on grain boundaries is proposed and tested against numerical simulations: this approach based on a grain explicit model (GEM) allows to consider the granular structure, yielding accurate predictions for a wide span of nucleation processes. Comparisons are made with classical models of homogeneous (JMAK) as well as heterogeneous (Cahn) nucleation. A transition scale based on material properties is proposed, allowing to discriminate between random and sit...

  13. Metabolic Abnormalities in growth hormone deficiency Anormalidades metabólicas en la deficiencia de la hormona de crecimiento

    Directory of Open Access Journals (Sweden)

    Roberto Lanes

    2008-12-01

    Full Text Available Increased cardiovascular morbidity and mortality has been reported in adult subjects with growth hormone deficiency (GHD. Long term follow up of a large cohort of patients with adult onset GHD, suggests that GH therapy may contribute to a reduced risk of nonfatal stroke, particularly in women and in a decline in nonfatal cardiac events in GHD men(1,2. Adult hypopituitary patients with untreated growth hormone deficiency have been shown to have a cluster of cardiovascular risk factors such as increased visceral adiposity, disturbances in lipoprotein metabolism, premature atherosclerosis, impaired fibrinolytic activity, increased peripheral insulin resistance, abnormal cardiac structure, impaired cardiac performance and endothelial dysfunction (3,4. Several of these risk factors have now been confirmed in double blind, randomized, placebo controlled trials (5,6. Metabolic changes in GH deficient children and adolescents have been evaluated only quite recently and superficially. In this article we will discuss these metabolic abnormalities and their underlying mechanism in untreated GHD subjects and we will review the beneficial effect of growth hormone therapy in adults, adolescents and children with GHD.Se ha reportado un aumento en la morbilidad y mortalidad de pacientes adultos con deficiencia de la hormona de crecimiento (DHC. El seguimiento a largo plazo de una cohorte de pacientes con DHC sugiere que la administracion de hormona de crecimiento puede contribuir a una reducción en el número de los accidentes cerebrovasculares no fatales, particularmente en mujeres y de eventos cardíacos en hombres(1,2. Pacientes adultos con hipopituitarismo y una DHC cursan con un acúmulo de factores de riesgo cardiovascular tales como un aumento en la adiposidad visceral, alteraciones en el metabolismo lipoproteico, ateroesclerosis prematura, actividad fibrinolítica alterada, resistencia a la insulina, masa y función cardíaca alterada y disfunci

  14. Using pollen grains as novel hydrophilic solid-phase extraction sorbents for the simultaneous determination of 16 plant growth regulators.

    Science.gov (United States)

    Lu, Qian; Wu, Jian-Hong; Yu, Qiong-Wei; Feng, Yu-Qi

    2014-11-01

    In this article, pollen grains were for the first time used as a hydrophilic solid-phase extraction (HILIC-SPE) sorbent for the determination of 16 plant growth regulators (PGRs) in fruits and vegetables. Fourier transform infrared spectroscopy (FT-IR), scanning electronic microscopy (SEM) and nitrogen sorption porosimetry (NSP) were used to investigate the chemical structure and the surface properties of the pollen grains. Pollen grains exhibited an excellent adsorption capacity for some polar compounds due to their particular functional groups. Several parameters influencing extraction performance were investigated. A green and simple HILIC-SPE-method using pollen grain cartridge for purification of fruit and vegetable extractions, followed by ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry (UHPLC-MS/MS) was established. Good linear relationships were obtained for 16 PGRs with correlation coefficients (R) above 0.9980. The limits of detection (LODs) of 16 PGRs in cucumber were in the range of 0.01-1.10 μg · kg(-1). Reproducibility of the method was evaluated by intra-day and inter-day precisions with relative standard deviations (RSDs), which were less than 14.4%. We successfully applied this methodology to analyze 16 PGRs in 8 different kinds of fruits and vegetables. The recoveries from samples spiked with 16 PGRs were from 80.5% to 119.2%, with relative standard deviations less than 15.0%.

  15. Establishment of growth medium and quantification of pollen grains of olive cultivars in Brazil's subtropical areas

    Directory of Open Access Journals (Sweden)

    Luiz Fernando de Oliveira da Silva

    2015-01-01

    Full Text Available ABSTRACT Pollen grain germination in vitro indicates viability and consequently provides information related to fruit set. It also assists in the development of hybrids. Along with a suitable species, a standard culture medium is essential for evaluating pollen viability. It should contain a gelling agent consisting of carbohydrates and enhancer elements as well as have the correct pH, temperature, and incubation time. The objective of this study was to optimise the culture medium, determine the pollen germination capacity, and quantify the number of pollen grains per flower of certain olive tree cultivars. A basic sequential culture medium for pollen grain germination was determined, always utilizing the best result from the previous experiment to continue the sequence.The factorial treatment arrangement was: 1 agar versus boric acid; 2 pH versus sucrose; 3 calcium nitrate versus magnesium sulfate. After determining the culture medium components, two experiments were conducted evaluating temperature and incubation time. Another experiment evaluated both the germination percentage and the number of flower pollen grains of 28 cultivars. The culture medium should be composed of 4 g∙L-1 of agar, 90 g∙L-1 of sucrose, and 400 mg∙L-1 of boric acid with a pH adjusted to 5.79 and an incubation time of 60 h at 28 °C. The Manzanilla 215 cultivar had the highest germination rate while Ascolano 315 presented the highest number of pollen grains per flower.

  16. Effects of Genotype and Growth Temperature on the Contents of Tannin, Phytate and In Vitro Iron Availability of Sorghum Grains.

    Directory of Open Access Journals (Sweden)

    Gangcheng Wu

    Full Text Available It has been predicted that the global temperature will rise in the future, which means crops including sorghum will likely be grown under higher temperatures, and consequently may affect the nutritional properties.The effects of two growth temperatures (OT, day/night 32/21°C; HT 38/21°C on tannin, phytate, mineral, and in vitro iron availability of raw and cooked grains (as porridge of six sorghum genotypes were investigated.Tannin content significantly decreased across all sorghum genotypes under high growth temperature (P ≤0.05, while the phytate and mineral contents maintained the same level, increased or decreased significantly, depending on the genotype. The in vitro iron availability in most sorghum genotypes was also significantly reduced under high temperature, except for Ai4, which showed a pronounced increase (P ≤0.05. The cooking process significantly reduced tannin content in all sorghum genotypes (P ≤0.05, while the phytate content and in vitro iron availability were not significantly affected.This research provides some new information on sorghum grain nutritional properties when grown under predicted future higher temperatures, which could be important for humans where sorghum grains are consumed as staple food.

  17. The Signature of Primordial Grain Growth in the Polarized Light of the AU Microscopii Debris Disk

    Science.gov (United States)

    Graham, James R.; Kalas, Paul G.; Matthews, Brenda C.

    2007-01-01

    We have used the Hubble Space Telescope Advanced Camera for Surveys coronagraph to make the first polarization maps of the AU Microscopii debris disk. The polarization rises from 5% at 20 AU to 40% at 80 AU. The polarization is perpendicular to the disk, indicating that the scattered light originates from micron-sized grains in an optically thin disk. Disk models show that interior to the ``birth ring'' (40-50 AU) there is a hole in the dust distribution where micron-sized dust is depleted by a factor of more than 300. The disk is collision dominated, and grains that fall inward due to drag forces undergo a destructive collision. The presence of this hole implies that the localized enhancements in surface brightness that occur at projected radii interior to the birth ring are caused by nonaxisymmetric structures in the outer disk. The grains exhibit strong forward scattering and high polarization. Spherical grains composed of conventional materials cannot reproduce these optical properties. A Mie/Maxwell-Garnett analysis demands highly porous (91%-94%) particles. In the inner solar system, porous particles form in cometary dust, where the sublimation of ices leaves a ``bird's nest'' of refractory material. In AU Mic, the grain porosity may be primordial, because the dust birth ring lies beyond the ice sublimation point. The observed porosities span the range of values implied by laboratory studies of particle coagulation by ballistic cluster-cluster aggregation. To avoid compactification, the upper size limit for the parent bodies is in the decimeter range, in agreement with theoretical predictions based on collisional lifetime arguments. Consequently, AU Mic may exhibit the signature of the primordial agglomeration process whereby interstellar grains first assembled to form macroscopic objects.

  18. Grain growth control and transparency in spark plasma sintered self-doped alumina materials

    International Nuclear Information System (INIS)

    Doping alumina particles with aluminum alkoxides allows dense spark plasma sintered (SPSed) materials to be obtained that have a refined grain size compared to pure materials, which is critical for their transparency. An optical model considering pore and grain size distributions has been developed to obtain information about porosity in dense materials. This work suggests that the atomic diffusion mechanisms do not depend on the sintering technique. A reduction in the activation energy by a factor of 2 has been found in SPSed materials.

  19. The structure and dielectric tunable properties of preferred oriented BST ceramics prepared by templated grain growth method

    International Nuclear Information System (INIS)

    In this work, textured barium strontium titanate ceramics with a high degree of preferred orientation were prepared by templated grain growth technique. The structure and dielectric tunable properties of textured BST ceramic were investigated. A high degree of fiber texture was achieved using oriented SrTiO3 as template particles in fine-grained BST matrix. The dielectric tunability of textured BST ceramic were significantly increased compared to random oriented ceramic. Furthermore the P-E curve of textured BST ceramic presented a more visible hysteresis loop. Combined with origin of the tunability, these effects could be interpreted on the base of both hardening mechanism of soft mode and polar nano-region mechanism

  20. Heat stress in wheat (Triticum aestivum L.) : Effects on grain growth and quality traits

    NARCIS (Netherlands)

    Spiertz, J.H.J.; Hamer, R.J.; Xu, H.; Primo Martin, C.; Don, C.; Putten, van der P.E.L.

    2006-01-01

    Heat stress effects on grain dry mass and quality were studied in spring wheat genotypes (Triticum aestivum L.). Three cultivars were chosen with respect to heat tolerance: Lavett (genotype 1), selected for temperate growing conditions and two CIMMYT cultivars, Ciano-79 (genotype 2) and Attila (geno

  1. Heat stress in wheat (Triticum aestivum L.): Effects on grain growth and quality traits

    NARCIS (Netherlands)

    Spiertz, J.H.J.; Hamer, R.J.; Xu, H.; Primo-Martin, C.; Don, C.; Putten, P.E.L. van der

    2006-01-01

    Heat stress effects on grain dry mass and quality were studied in spring wheat genotypes (Triticum aestivum L.). Three cultivars were chosen with respect to heat tolerance: Lavett (genotype 1), selected for temperate growing conditions and two CIMMYT cultivars, Ciano-79 (genotype 2) and Attila (geno

  2. Curved walls: Grain growth, settling, and composition patterns in T Tauri disk dust submlimation fronts

    CERN Document Server

    McClure, M K; Calvet, N; Espaillat, C; Hartmann, L; Sargent, B; Watson, D M; Ingleby, L; Hernandez, J

    2013-01-01

    The dust sublimation walls of disks around T Tauri stars represent a directly observable cross-section through the disk atmosphere and midplane. Their emission properties can probe the grain size distribution and composition of the innermost regions of the disk, where terrestrial planets form. Here we calculate the inner dust sublimation wall properties for four classical T Tauri stars with a narrow range of spectral types and inclination angles and a wide range of mass accretion rates to determine the extent to which the walls are radially curved. Best-fits to the near- and mid-IR excesses are found for curved, 2-layer walls in which the lower layer contains larger, hotter, amorphous pyroxene grains with Mg/(Mg+Fe)=0.6 and the upper layer contains submicron, cooler, mixed amorphous olivine and forsterite grains. As the mass accretion rates decrease from 10^(-8) to 10^(-10) Msol/yr, the maximum grain size in the lower layer decreases from 3 to 0.5 microns. We attribute this to a decrease in fragmentation and ...

  3. Partial rescue of postnatal growth plate abnormalities in Ihh mutants by expression of a constitutively active PTH/PTHrP receptor

    OpenAIRE

    Maeda, Yukiko; Schipani, Ernestina; Densmore, Michael J.; Lanske, Beate

    2009-01-01

    Indian hedgehog (Ihh) is essential for chondrocyte proliferation/differentiation and osteoblast differentiation during prenatal endochondral bone formation. Ihh expression in postnatal chondrocytes has a non-redundant role in maintaining a growth plate and sustaining trabecular bone after birth. Loss of Ihh in postnatal chondrocytes results in fusion of the growth plate and a decrease in trabecular bone. In order to normalize this abnormal chondrocyte phenotype and to investigate whether a pu...

  4. Heterologous expression of a ketohexokinase in potato plants leads to inhibited rates of photosynthesis, severe growth retardation and abnormal leaf development

    DEFF Research Database (Denmark)

    Geigenberger, P.; Regierer, B.; Lytovchenko, A.;

    2004-01-01

    of ketohexokinase but did not accumulate fructose 1-phosphate. They were, however, characterised by a severe growth retardation and abnormal leaf development. Studies of (14)CO(2) assimilation and metabolism, and of the levels of photosynthetic pigments, revealed that these lines exhibited restricted photosynthesis...

  5. The Herschel exploitation of local galaxy Andromeda (HELGA) VI: Strengthening the case for substantial interstellar grain growth

    CERN Document Server

    Mattsson, L; Andersen, A C; Smith, M W L; De Looze, I; Baes, M; Viaene, S; Gentile, G; Fritz, J; Spinoglio, L

    2014-01-01

    In this paper we consider the implications of the distributions of dust and metals in the disc of M31. We derive mean radial dust distributions using a dust map created from Herschel images of M31 sampling the entire far-infrared (FIR) peak. Modified blackbodies are fit to approximately 4000 pixels with a varying, as well as a fixed, dust emissivity index (beta). An overall metal distribution is also derived using data collected from the literature. We use a simple analytical model of the evolution of the dust in a galaxy with dust contributed by stellar sources and interstellar grain growth, and fit this model to the radial dust-to-metals distribution across the galaxy. Our analysis shows that the dust-to-gas gradient in M31 is steeper than the metallicity gradient, suggesting interstellar dust growth is (or has been) important in M31. We argue that M31 helps build a case for cosmic dust in galaxies being the result of substantial interstellar grain growth, while the net dust production from stars may be lim...

  6. The Difference in Growth and Four Microelement Concentrations Between Two Rice Genotypes Differing in Grain Cadmium-Accumulating Capacity

    Institute of Scientific and Technical Information of China (English)

    CHENG Wang-da; ZHANG Guo-ping; YAO Hai-gen; Peter Dominy; WANG Run-yi

    2004-01-01

    A pot experiment was conducted with two rice genotypes having different Cd concentrations in their grains to study the effect of soil Cd level on biomass, Cd and Fe, Zn, Cr and Pb accumulation in different plant parts. Cd was added into soil to form 4 levels, i.e.,0, 0.5, 2.5 and 12.5 mg kg-1, respectively. The results showed that the Cd-induced reduction in biomass accumulation varied in both genotypes and growth stages. The Cd-induced reduction in biomass became less with the progress of growth, and Xiushui63, a genotype with relatively higher grain Cd concentration, was more severely inhibited than Xiushui217,a relatively lower Cd concentration. Both Cd concentration and accumulation in the various plant parts increased substantially with the increase of Cd levels. The difference between two genotypes in Cd concentration and accumulation became more pronounced with increased Cd level as well as prolonged duration of exposure. Xuishui63 had much greater Cd accumulation than Xiushui217, in particular at late growth stage. Xuishui63 had a remarkably higher Cd translocation of roots to shoots than Xiushui217 in all Cd levels.The effect of Cd addition on four microelement concentrations in straw and milled rice also varied in genotypes and Cd levels. Without Cd addition, Xiushui63 was significantly lower than Xiushui217 in the concentrations of all four elements in straw, while the case was just opposite in milled rice. Zn, Fe and Pb concentrations decreased in milled rice with the increase of Cd level, although the reduction extent differed in two genotypes.The results indicated that Cd concentration in rice grain is primarily dependent on the shoot Cd concentration, which is in turn mainly determined by Cd translocation from roots to shoots.

  7. Inversion boundary induced grain growth in ZnO ceramics: from atomic-scale investigations to microstructural engineering

    International Nuclear Information System (INIS)

    In semiconducting materials special boundaries play the key role in crystal growth. They introduce an abrupt structural and chemical anisotropy, which is readily reflected in an unusual microstructure evolution, whereas their local structure affects the physical properties of semiconducting materials. These effects, however, can be exploited to tailor the electronic and optical properties of the materials, as demonstrated in this review. The presented topic fits in the field of preparatory stage of phase transformations, manifested through evolution of chemically induced structural faults. In the noncentrosymmetric structure of ZnO, inversion boundaries (IBs) are the most common type of planar faults that can be triggered by the addition of specific spinel-forming dopants (Sb2O3, SnO2, TiO2). In addition to conventional HRTEM techniques several new methods were developed to resolve crystallography and atomic-scale chemistry of IBs. The absolute orientation of the polar c-axes on both sides of the IB was determined by a novel quantitative microdiffraction method, providing a reliable identification of crystal polarity in noncentrosymmetric crystals. To determine sub-monolayer quantities of dopants on the IB, we developed a special technique of analytical electron microscopy using concentric electron probe (CEP) in EDS or EELS mode, providing more accurate and precise results than any other available technique. Knowing the local crystal chemistry of IBs we were able to design experiments to identify their formation mechanism. IBs nucleate in the early stage of grain growth as a dopant-rich topotaxial 2D reaction product on Zn-terminated surfaces of ZnO grains. Soon after their nucleation, ZnO is epitaxially grown on the inherent 2D phase in an inverted orientation, which effectively starts to dictate anisotropic growth of the infected crystallite. In very short time the grains with IBs dominate the entire microstructure in ZnO ceramics via IB-induced exaggerated

  8. Sintering process and grain growth of Mn-Zn ferrite nanoparticles

    Institute of Scientific and Technical Information of China (English)

    WANG Xin; CUI Yinfang; WANG Yongming; HAO Shunli; LIU Chunjing

    2006-01-01

    The density, microstructure and magnetic properties of non-doped Mn-Zn ferrite nanoparticles sintered compacts were investigated. The compacts of non-doped Mn-Zn ferrite nanoparticles were sintered by segmented-sintering process at lower sintering temperature. The density of sintered samples was measured by Archimedes method, and the phase composition and microstructure were examined by XRD and SEM. The sintered Mn-Zn ferrite magnetic measurements were carried out with Vibrating Sample. The results show that the density of sintered compacts increases with the rising of sintering temperature, achieving 4.8245 g·cm-3 when sintered at 900 ℃, which is the optimal density of Mn-Zn functional ferrite needed and from the fractured surface of sintered samples, it can be seen that the grain grows well with small grain size and homogeneous distribution.

  9. Impact of integrated nutrient management on growth and grain yield of wheat under irrigated cropping system

    International Nuclear Information System (INIS)

    Field study was conducted during 2001-02 and 2002-03 to investigate the effect of cropping patterns and farm yard manure, potassium and zinc on the grain yield of wheat. Trials were conducted at Agricultural Research Farm, KPK Agricultural University Peshawar, Pakistan. Two factors cropping patterns and manures/fertilizers were studied in the experiment. Randomized complete block design was used with split plot arrangements and four replications having net plot size of 12 m/sup 2/. Wheat variety Ghaznavi-98 was sown in November soon after ploughing the soil at proper moisture level suitable for wheat seed germination. Five cropping patterns were allotted to main plots and the eight combinations of FYM, K and Zn to the sub-plots. Same plots were used for next year sowing. Effects of five cropping patterns i.e., rice-wheat, maize-wheat, sunflower-wheat, sorghum-wheat and pigeon pea-wheat and three organic and in-organic fertilizers (Farmyard Manure, Potassium and Zinc) on subsequent wheat crop were observed. Highest grain yield was obtained when wheat was planted after pigeon pea. Manures/fertilizer application (Farmyard Manure, Potassium and Zinc) produced significantly higher grain yield than the control plots. The findings of the present study revealed that leguminous crops can significantly increase the yield of succeeding crops. Thus use of Farmyard Manure, Potassium and Zinc should be included in integrated crop management approaches for sustainable agriculture. (author)

  10. Thickness dependence of grain growth orientation in MgB2 films fabricated by hybrid physical-chemical vapor deposition

    International Nuclear Information System (INIS)

    We have investigated the effect of thickness of the MgB2 film on the grain growth direction as well as on their superconducting properties. MgB2 films of various thicknesses were fabricated on c-cut Al2O3 substrates at a temperature of 540 degree by using hybrid physical-chemical vapor deposition (HPCVD) technique. The superconducting transition temperature (Tc) was found to increase with increase in the thickness of the MgB2 film. X-ray diffraction analysis revealed that the orientation of grains changed from c-axis to a-axis upon increasing the thickness of the MgB2 film from 0.6 to 2.0 μm. MgB2 grains of various orientations were observed in the microstructures of the films examined by scanning electron microscopy. It is observed that at high magnetic fields the 2.0-μm-thick film exhibit considerably larger critical current density (Jc) as compared to 0.6-μm-thick film. The results are discussed in terms of an intrinsic-pinning in MgB2 similarly as intrinsic-pinning occurring in high-Tc cuprate superconductors with layered structure.

  11. Cholinergic Abnormalities, Endosomal Alterations and Up-Regulation of Nerve Growth Factor Signaling in Niemann-Pick Type C Disease

    Directory of Open Access Journals (Sweden)

    Cabeza Carolina

    2012-03-01

    Full Text Available Abstract Background Neurotrophins and their receptors regulate several aspects of the developing and mature nervous system, including neuronal morphology and survival. Neurotrophin receptors are active in signaling endosomes, which are organelles that propagate neurotrophin signaling along neuronal processes. Defects in the Npc1 gene are associated with the accumulation of cholesterol and lipids in late endosomes and lysosomes, leading to neurodegeneration and Niemann-Pick type C (NPC disease. The aim of this work was to assess whether the endosomal and lysosomal alterations observed in NPC disease disrupt neurotrophin signaling. As models, we used i NPC1-deficient mice to evaluate the central cholinergic septo-hippocampal pathway and its response to nerve growth factor (NGF after axotomy and ii PC12 cells treated with U18666A, a pharmacological cellular model of NPC, stimulated with NGF. Results NPC1-deficient cholinergic cells respond to NGF after axotomy and exhibit increased levels of choline acetyl transferase (ChAT, whose gene is under the control of NGF signaling, compared to wild type cholinergic neurons. This finding was correlated with increased ChAT and phosphorylated Akt in basal forebrain homogenates. In addition, we found that cholinergic neurons from NPC1-deficient mice had disrupted neuronal morphology, suggesting early signs of neurodegeneration. Consistently, PC12 cells treated with U18666A presented a clear NPC cellular phenotype with a prominent endocytic dysfunction that includes an increased size of TrkA-containing endosomes and reduced recycling of the receptor. This result correlates with increased sensitivity to NGF, and, in particular, with up-regulation of the Akt and PLC-γ signaling pathways, increased neurite extension, increased phosphorylation of tau protein and cell death when PC12 cells are differentiated and treated with U18666A. Conclusions Our results suggest that the NPC cellular phenotype causes neuronal

  12. Zirconium Carbide Produced by Spark Plasma Sintering and Hot Pressing: Densification Kinetics, Grain Growth, and Thermal Properties

    Directory of Open Access Journals (Sweden)

    Xialu Wei

    2016-07-01

    Full Text Available Spark plasma sintering (SPS has been employed to consolidate a micron-sized zirconium carbide (ZrC powder. ZrC pellets with a variety of relative densities are obtained under different processing parameters. The densification kinetics of ZrC powders subjected to conventional hot pressing and SPS are comparatively studied by applying similar heating and loading profiles. Due to the lack of electric current assistance, the conventional hot pressing appears to impose lower strain rate sensitivity and higher activation energy values than those which correspond to the SPS processing. A finite element simulation is used to analyze the temperature evolution within the volume of ZrC specimens subjected to SPS. The control mechanism for grain growth during the final SPS stage is studied via a recently modified model, in which the grain growth rate dependence on porosity is incorporated. The constant pressure specific heat and thermal conductivity of the SPS-processed ZrC are determined to be higher than those reported for the hot-pressed ZrC and the benefits of applying SPS are indicated accordingly.

  13. Growth temperature and genotype both play important roles in sorghum grain phenolic composition

    OpenAIRE

    Gangcheng Wu; Johnson, Stuart K.; Bornman, Janet F.; Bennett, Sarita J.; Clarke, Michael W.; Vijaya Singh; Zhongxiang Fang

    2016-01-01

    Polyphenols in sorghum grains are a source of dietary antioxidants. Polyphenols in six diverse sorghum genotypes grown under two day/night temperature regimes of optimal temperature (OT, 32/21 °C and high temperature (HT, 38/21 °C) were investigated. A total of 23 phenolic compounds were positively or tentatively identified by HPLC-DAD-ESIMS. Compared with other pigmented types, the phenolic profile of white sorghum PI563516 was simpler, since fewer polyphenols were detected. Brown sorghum IS...

  14. Constraints on the Radial Variation of Grain Growth in the AS 209 Circumstellar Disk

    CERN Document Server

    Pérez, Laura M; Chandler, Claire J; Isella, Andrea; Andrews, Sean M; Ricci, Luca; Calvet, Nuria; Corder, Stuartt A; Deller, Adam T; Dullemond, Cornelis P; Greaves, Jane S; Harris, Robert J; Henning, Thomas; Kwon, Woojin; Lazio, Joseph; Linz, Hendrik; Mundy, Lee G; Sargent, Anneila I; Storm, Shaye; Testi, Leonardo; Wilner, David J

    2012-01-01

    We present dust continuum observations of the protoplanetary disk surrounding the pre-main sequence star AS 209, spanning more than an order of magnitude in wavelength from 0.88 to 9.8 mm. The disk was observed with sub-arcsecond angular resolution (0.2"-0.5") to investigate radial variations in its dust properties. At longer wavelengths, the disk emission structure is notably more compact, providing model-independent evidence for changes in the grain properties across the disk. We find that physical models which reproduce the disk emission require a radial dependence of the dust opacity \\kappa_{\

  15. Growth temperature and genotype both play important roles in sorghum grain phenolic composition.

    Science.gov (United States)

    Wu, Gangcheng; Johnson, Stuart K; Bornman, Janet F; Bennett, Sarita J; Clarke, Michael W; Singh, Vijaya; Fang, Zhongxiang

    2016-01-01

    Polyphenols in sorghum grains are a source of dietary antioxidants. Polyphenols in six diverse sorghum genotypes grown under two day/night temperature regimes of optimal temperature (OT, 32/21 °C and high temperature (HT, 38/21 °C) were investigated. A total of 23 phenolic compounds were positively or tentatively identified by HPLC-DAD-ESIMS. Compared with other pigmented types, the phenolic profile of white sorghum PI563516 was simpler, since fewer polyphenols were detected. Brown sorghum IS 8525 had the highest levels of caffeic and ferulic acid, but apigenin and luteolin were not detected. Free luteolinidin and apigeninidin levels were lower under HT than OT across all genotypes (p ≤ 0.05), suggesting HT could have inhibited 3-deoxyanthocyanidins formation. These results provide new information on the effects of HT on specific polyphenols in various Australian sorghum genotypes, which might be used as a guide to grow high antioxidant sorghum grains under projected high temperature in the future. PMID:26907726

  16. INFRARED SPECTROSCOPIC SURVEY OF THE QUIESCENT MEDIUM OF NEARBY CLOUDS. I. ICE FORMATION AND GRAIN GROWTH IN LUPUS

    Energy Technology Data Exchange (ETDEWEB)

    Boogert, A. C. A. [IPAC, NASA Herschel Science Center, Mail Code 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Chiar, J. E. [SETI Institute, Carl Sagan Center, 189 Bernardo Avenue, Mountain View, CA 94043 (United States); Knez, C.; Mundy, L. G. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Öberg, K. I. [Departments of Chemistry and Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Pendleton, Y. J. [Solar System Exploration Research Virtual Institute, NASA Ames Research Center, Moffett Field, CA 94035 (United States); Tielens, A. G. G. M.; Van Dishoeck, E. F., E-mail: aboogert@ipac.caltech.edu [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)

    2013-11-01

    Infrared photometry and spectroscopy (1-25 μm) of background stars reddened by the Lupus molecular cloud complex are used to determine the properties of grains and the composition of ices before they are incorporated into circumstellar envelopes and disks. H{sub 2}O ices form at extinctions of A{sub K} = 0.25 ± 0.07 mag (A{sub V} = 2.1 ± 0.6). Such a low ice formation threshold is consistent with the absence of nearby hot stars. Overall, the Lupus clouds are in an early chemical phase. The abundance of H{sub 2}O ice (2.3 ± 0.1 × 10{sup –5} relative to N{sub H}) is typical for quiescent regions, but lower by a factor of three to four compared to dense envelopes of young stellar objects. The low solid CH{sub 3}OH abundance (<3%-8% relative to H{sub 2}O) indicates a low gas phase H/CO ratio, which is consistent with the observed incomplete CO freeze out. Furthermore it is found that the grains in Lupus experienced growth by coagulation. The mid-infrared (>5 μm) continuum extinction relative to A{sub K} increases as a function of A{sub K}. Most Lupus lines of sight are well fitted with empirically derived extinction curves corresponding to R{sub V} ∼ 3.5 (A{sub K} = 0.71) and R{sub V} ∼ 5.0 (A{sub K} = 1.47). For lines of sight with A{sub K} > 1.0 mag, the τ{sub 9.7}/A{sub K} ratio is a factor of two lower compared to the diffuse medium. Below 1.0 mag, values scatter between the dense and diffuse medium ratios. The absence of a gradual transition between diffuse and dense medium-type dust indicates that local conditions matter in the process that sets the τ{sub 9.7}/A{sub K} ratio. This process is likely related to grain growth by coagulation, as traced by the A{sub 7.4}/A{sub K} continuum extinction ratio, but not to ice mantle formation. Conversely, grains acquire ice mantles before the process of coagulation starts.

  17. INFRARED SPECTROSCOPIC SURVEY OF THE QUIESCENT MEDIUM OF NEARBY CLOUDS. I. ICE FORMATION AND GRAIN GROWTH IN LUPUS

    International Nuclear Information System (INIS)

    Infrared photometry and spectroscopy (1-25 μm) of background stars reddened by the Lupus molecular cloud complex are used to determine the properties of grains and the composition of ices before they are incorporated into circumstellar envelopes and disks. H2O ices form at extinctions of AK = 0.25 ± 0.07 mag (AV = 2.1 ± 0.6). Such a low ice formation threshold is consistent with the absence of nearby hot stars. Overall, the Lupus clouds are in an early chemical phase. The abundance of H2O ice (2.3 ± 0.1 × 10–5 relative to NH) is typical for quiescent regions, but lower by a factor of three to four compared to dense envelopes of young stellar objects. The low solid CH3OH abundance (2O) indicates a low gas phase H/CO ratio, which is consistent with the observed incomplete CO freeze out. Furthermore it is found that the grains in Lupus experienced growth by coagulation. The mid-infrared (>5 μm) continuum extinction relative to AK increases as a function of AK. Most Lupus lines of sight are well fitted with empirically derived extinction curves corresponding to RV ∼ 3.5 (AK = 0.71) and RV ∼ 5.0 (AK = 1.47). For lines of sight with AK > 1.0 mag, the τ9.7/AK ratio is a factor of two lower compared to the diffuse medium. Below 1.0 mag, values scatter between the dense and diffuse medium ratios. The absence of a gradual transition between diffuse and dense medium-type dust indicates that local conditions matter in the process that sets the τ9.7/AK ratio. This process is likely related to grain growth by coagulation, as traced by the A7.4/AK continuum extinction ratio, but not to ice mantle formation. Conversely, grains acquire ice mantles before the process of coagulation starts

  18. Influences of oxygen partial pressure on YBCO grain growth by a zone melting method

    International Nuclear Information System (INIS)

    This study reports investigation on influences of Y endash Ba endash Cu endash O compounds solidification under different oxygen partial pressures by a zone melting method. In Y endash Ba endash Cu endash O system, P(O2) ranged from 0.02 to 1 atm, following reaction occurred during heating: YBa2Cu3O6+δ(Y123)→Y2BaCuO5(Y211)+L. With an increase of oxygen partial pressure or decrease of pulling rate, the morphology of solidified interface changed from mushy to equiaxed, cellular, and planar. The continuous Y123 grains were readily obtained under high oxygen partial pressure. Based on the constitutional supercooling theory and combining the result of the yttrium solubility limit for different oxygen partial pressures, the influences of oxygen partial pressure on Y123 morphological evolution were clarified. copyright 1996 Materials Research Society

  19. Investigation of fatigue crack growth rate of Al 5484 ultrafine grained alloy after ECAP process

    Energy Technology Data Exchange (ETDEWEB)

    Brynk, Tomasz; Rasinski, Marcin; Pakiela, Zbigniew; Kurzydlowski, Krzysztof J. [Faculty of Materials Science and Engineering, Warsaw University of Technology (Poland); Olejnik, Lech [Faculty of Production Engineering, Warsaw University of Technology (Poland)

    2010-05-15

    During the last decade equal-channel angular pressing (ECAP) has emerged as a widely used fabrication route of ultrafine-grained (UFG) metals and alloys. Enhanced mechanical properties of UFG materials produced by severe plastic deformation, with a grain size smaller than 1 {mu}m, have been reported in a large number of publications. However, the higher strength does not imply higher resistance to fatigue both high- and low-cyclic. In fact, due to reduced plasticity, higher fatigue crack propagation rates are reported for UFG materials, particularly in low-amplitude range. The aim of this work was to investigate fatigue crack propagation in samples of Al 5483 alloy subjected to ECAP treatment. Because of small dimensions of the coupons processed by ECAP, non-standard, mini-samples were used in a crack propagation tests. Two test procedures were used to estimate stress intensity factor (K). The first was based on optical measurements of crack length from images recorded during the test. The second method was based on digital image correlation (DIC), which was used to determine K value directly from displacement field near the crack tip. Comparison of these two methods is made and the relationship between the intensity of ECAP process (measured in terms of the number of ECAP passes) and fatigue crack propagation rates proposed. In addition to fatigue resistance, the results of tensile tests carried out with mini-samples are presented. Applicability of such samples in the investigations of the mechanical properties of UFG materials is discussed. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  20. On the mechanisms governing the texture and microstructure evolution during static recrystallization and grain growth of low alloyed zirconium sheets (Zr702)

    International Nuclear Information System (INIS)

    Low alloyed zirconium sheets (Zr702) have been cold-rolled up to 80% thickness reduction and submitted to various isothermal treatments. The aim was to identify the mechanisms which produce microstructure and texture changes during recrystallization and grain growth. XRD and texture analysis, FEG-SEM with EBSD as well as TEM were used to analyze the various specimens. Three types of substructures were observed in the initial deformed material. Accordingly, the nucleation starts in the most deformed areas and continues in the somewhat less deformed areas, which corresponds to a non oriented nucleation and results in a set of new grains, the size of which is very rapidly stabilized. In the last stage of recrystallization, the grains which have resisted the recrystallization disappear progressively by several mechanisms including in situ recrystallization. Therefore, the texture at the end of the recrystallization resembles the one of the deformed state. Normal grain growth leads to a moderate grain size increase due to the precipitates which slow down the grain boundary motion. This is also the stage where the texture changes due to the size advantage, after recrystallization, of grains in some specific orientations. (orig.)

  1. On the mechanisms governing the texture and microstructure evolution during static recrystallization and grain growth of low alloyed zirconium sheets (Zr702)

    Energy Technology Data Exchange (ETDEWEB)

    Dewobroto, N. [LETAM (Lab. d' Etude des Textures et Application aux Materiaux), Univ. Paul Verlaine, Metz (France); Dept. of Microstructure Physics and Metal Forming, Max Planck Inst. for Iron Research, Duesseldorf (Germany); Bozzolo, N.; Wagner, F. [LETAM (Lab. d' Etude des Textures et Application aux Materiaux), Univ. Paul Verlaine, Metz (France); Barberis, P. [Cezus Research Centre, Ugine (France)

    2006-06-15

    Low alloyed zirconium sheets (Zr702) have been cold-rolled up to 80% thickness reduction and submitted to various isothermal treatments. The aim was to identify the mechanisms which produce microstructure and texture changes during recrystallization and grain growth. XRD and texture analysis, FEG-SEM with EBSD as well as TEM were used to analyze the various specimens. Three types of substructures were observed in the initial deformed material. Accordingly, the nucleation starts in the most deformed areas and continues in the somewhat less deformed areas, which corresponds to a non oriented nucleation and results in a set of new grains, the size of which is very rapidly stabilized. In the last stage of recrystallization, the grains which have resisted the recrystallization disappear progressively by several mechanisms including in situ recrystallization. Therefore, the texture at the end of the recrystallization resembles the one of the deformed state. Normal grain growth leads to a moderate grain size increase due to the precipitates which slow down the grain boundary motion. This is also the stage where the texture changes due to the size advantage, after recrystallization, of grains in some specific orientations. (orig.)

  2. An evaluation on fatigue crack growth in a fine-grained isotropic graphite

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hongtao; Sun Libin [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Li Chenfeng [College of Engineering, Swansea University, Singleton Park, Swansea SA2 8PP (United Kingdom); Shi Li [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Wang Haitao, E-mail: wanght@tsinghua.edu.cn [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer The propagation of micro- and macro-fatigue cracks in IG-11 graphite was studied. Black-Right-Pointing-Pointer The curves of the fatigue crack growth rate versus the SIF range show three stages. Black-Right-Pointing-Pointer The fatigue microcrack propagation is very sensitive to graphite's microstructures. Black-Right-Pointing-Pointer Graphite's microstructures have no significant impact on fatigue macrocrack growth. Black-Right-Pointing-Pointer The fatigue fracture surface indicates the fracture mechanism of the IG-11 graphite. - Abstract: The aim of this paper is to investigate the mechanism of fatigue crack propagation in IG-11 graphite, and determine the crack growth rate in relation to the stress level. Experimental studies were performed at both micro and macro scales. For fatigue microcrack propagation, single-edge-notch specimens were chosen for testing and the fatigue crack growth was measured in situ with a scanning electron microscope. For fatigue macrocrack propagation, CT specimens were used and the fatigue crack growth was measured with a high-accuracy optic microscope. Combining the two groups of experimental results, the following conclusions are derived: (1) The heterogeneous microstructures of the graphite material have significant impact on the fatigue microcrack growth, while their influence on fatigue macrocrack growth is very limited. (2) The relationship between the fatigue crack growth rate and the crack-tip stress intensity factor range can be expressed in the form of Paris formulae, which contains three stages: an initial rising part with a small slope, an abrupt rise with a very large acceleration, and a short final part with a small slope. (3) The fatigue fracture surface of the graphite material contains considerable sliding of leaf-shape graphite flakes combined with small cotton-shape plastic deformations. These sliding traces are approximately aligned at 45 Degree-Sign , showing the

  3. In vitro growth environment produces lipidomic and electron transport chain abnormalities in mitochondria from non-tumorigenic astrocytes and brain tumours

    Directory of Open Access Journals (Sweden)

    Thomas N Seyfried

    2009-05-01

    Full Text Available The mitochondrial lipidome influences ETC (electron transport chain and cellular bioenergetic efficiency. Brain tumours are largely dependent on glycolysis for energy due to defects in mitochondria and oxidative phosphorylation. In the present study, we used shotgun lipidomics to compare the lipidome in highly purified mitochondria isolated from normal brain, from brain tumour tissue, from cultured tumour cells and from non-tumorigenic astrocytes. The tumours included the CT-2A astrocytoma and an EPEN (ependymoblastoma, both syngeneic with the C57BL/6J (B6 mouse strain. The mitochondrial lipidome in cultured CT-2A and EPEN tumour cells were compared with those in cultured astrocytes and in solid tumours grown in vivo. Major differences were found between normal tissue and tumour tissue and between in vivo and in vitro growth environments for the content or composition of ethanolamine glycerophospholipids, phosphatidylglycerol and cardiolipin. The mitochondrial lipid abnormalities in solid tumours and in cultured cells were associated with reductions in multiple ETC activities, especially Complex I. The in vitro growth environment produced lipid and ETC abnormalities in cultured non-tumorigenic astrocytes that were similar to those associated with tumorigenicity. It appears that the culture environment obscures the boundaries of the Crabtree and the Warburg effects. These results indicate that in vitro growth environments can produce abnormalities in mitochondrial lipids and ETC activities, thus contributing to a dependency on glycolysis for ATP production.

  4. Responses of Rapid Viscoanalyzer Profile and Other Rice Grain Qualities to Exogenously Applied Plant Growth Regulators under High Day and High Night Temperatures.

    Science.gov (United States)

    Fahad, Shah; Hussain, Saddam; Saud, Shah; Hassan, Shah; Chauhan, Bhagirath Singh; Khan, Fahad; Ihsan, Muhammad Zahid; Ullah, Abid; Wu, Chao; Bajwa, Ali Ahsan; Alharby, Hesham; Amanullah; Nasim, Wajid; Shahzad, Babar; Tanveer, Mohsin; Huang, Jianliang

    2016-01-01

    High-temperature stress degrades the grain quality of rice; nevertheless, the exogenous application of plant growth regulators (PGRs) might alleviate the negative effects of high temperatures. In the present study, we investigated the responses of rice grain quality to exogenously applied PGRs under high day temperatures (HDT) and high night temperatures (HNT) under controlled conditions. Four different combinations of ascorbic acid (Vc), alpha-tocopherol (Ve), brassinosteroids (Br), methyl jasmonates (MeJA) and triazoles (Tr) were exogenously applied to two rice cultivars (IR-64 and Huanghuazhan) prior to the high-temperature treatment. A Nothing applied Control (NAC) was included for comparison. The results demonstrated that high-temperature stress was detrimental for grain appearance and milling qualities and that both HDT and HNT reduced the grain length, grain width, grain area, head rice percentage and milled rice percentage but increased the chalkiness percentage and percent area of endosperm chalkiness in both cultivars compared with ambient temperature (AT). Significantly higher grain breakdown, set back, consistence viscosity and gelatinization temperature, and significantly lower peak, trough and final viscosities were observed under high-temperature stress compared with AT. Thus, HNT was more devastating for grain quality than HDT. The exogenous application of PGRs ameliorated the adverse effects of high temperature in both rice cultivars, and Vc+Ve+MejA+Br was the best combination for both cultivars under high temperature stress.

  5. Responses of Rapid Viscoanalyzer Profile and Other Rice Grain Qualities to Exogenously Applied Plant Growth Regulators under High Day and High Night Temperatures

    Science.gov (United States)

    Fahad, Shah; Hussain, Saddam; Saud, Shah; Hassan, Shah; Chauhan, Bhagirath Singh; Khan, Fahad; Ihsan, Muhammad Zahid; Ullah, Abid; Wu, Chao; Bajwa, Ali Ahsan; Alharby, Hesham; Amanullah; Nasim, Wajid; Shahzad, Babar; Tanveer, Mohsin; Huang, Jianliang

    2016-01-01

    High-temperature stress degrades the grain quality of rice; nevertheless, the exogenous application of plant growth regulators (PGRs) might alleviate the negative effects of high temperatures. In the present study, we investigated the responses of rice grain quality to exogenously applied PGRs under high day temperatures (HDT) and high night temperatures (HNT) under controlled conditions. Four different combinations of ascorbic acid (Vc), alpha-tocopherol (Ve), brassinosteroids (Br), methyl jasmonates (MeJA) and triazoles (Tr) were exogenously applied to two rice cultivars (IR-64 and Huanghuazhan) prior to the high-temperature treatment. A Nothing applied Control (NAC) was included for comparison. The results demonstrated that high-temperature stress was detrimental for grain appearance and milling qualities and that both HDT and HNT reduced the grain length, grain width, grain area, head rice percentage and milled rice percentage but increased the chalkiness percentage and percent area of endosperm chalkiness in both cultivars compared with ambient temperature (AT). Significantly higher grain breakdown, set back, consistence viscosity and gelatinization temperature, and significantly lower peak, trough and final viscosities were observed under high-temperature stress compared with AT. Thus, HNT was more devastating for grain quality than HDT. The exogenous application of PGRs ameliorated the adverse effects of high temperature in both rice cultivars, and Vc+Ve+MejA+Br was the best combination for both cultivars under high temperature stress. PMID:27472200

  6. Formation of Graphene Grain Boundaries on Cu(100) Surface and a Route Towards Their Elimination in Chemical Vapor Deposition Growth

    Science.gov (United States)

    Yuan, Qinghong; Song, Guangyao; Sun, Deyan; Ding, Feng

    2014-10-01

    Grain boundaries (GBs) in graphene prepared by chemical vapor deposition (CVD) greatly degrade the electrical and mechanical properties of graphene and thus hinder the applications of graphene in electronic devices. The seamless stitching of graphene flakes can avoid GBs, wherein the identical orientation of graphene domain is required. In this letter, the graphene orientation on one of the most used catalyst surface -- Cu(100) surface, is explored by density functional theory (DFT) calculations. Our calculation demonstrates that a zigzag edged hexagonal graphene domain on a Cu(100) surface has two equivalent energetically preferred orientations, which are 30 degree away from each other. Therefore, the fusion of graphene domains on Cu(100) surface during CVD growth will inevitably lead to densely distributed GBs in the synthesized graphene. Aiming to solve this problem, a simple route, that applies external strain to break the symmetry of the Cu(100) surface, was proposed and proved efficient.

  7. Formation of graphene grain boundaries on Cu(100) surface and a route towards their elimination in chemical vapor deposition growth.

    Science.gov (United States)

    Yuan, Qinghong; Song, Guangyao; Sun, Deyan; Ding, Feng

    2014-01-01

    Grain boundaries (GBs) in graphene prepared by chemical vapor deposition (CVD) greatly degrade the electrical and mechanical properties of graphene and thus hinder the applications of graphene in electronic devices. The seamless stitching of graphene flakes can avoid GBs, wherein the identical orientation of graphene domain is required. In this letter, the graphene orientation on one of the most used catalyst surface - Cu(100) surface, is explored by density functional theory (DFT) calculations. Our calculation demonstrates that a zigzag edged hexagonal graphene domain on a Cu(100) surface has two equivalent energetically preferred orientations, which are 30 degree away from each other. Therefore, the fusion of graphene domains on Cu(100) surface during CVD growth will inevitably lead to densely distributed GBs in the synthesized graphene. Aiming to solve this problem, a simple route, that applies external strain to break the symmetry of the Cu(100) surface, was proposed and proved efficient. PMID:25286970

  8. Crossing barriers in planetesimal formation: The growth of mm-dust aggregates with large constituent grains

    CERN Document Server

    Jankowski, Tim; Kelling, Thorben; Teiser, Jens; Sabolo, Walter; Gutiérrez, Pedro J; Bertini, Ivano; 10.1051/0004-6361/201218984

    2012-01-01

    Collisions of mm-size dust aggregates play a crucial role in the early phases of planet formation. We developed a laboratory setup to observe collisions of dust aggregates levitating at mbar pressures and elevated temperatures of 800 K. We report on collisions between basalt dust aggregates of from 0.3 to 5 mm in size at velocities between 0.1 and 15 cm/s. Individual grains are smaller than 25 \\mum in size. We find that for all impact energies in the studied range sticking occurs at a probability of 32.1 \\pm 2.5% on average. In general, the sticking probability decreases with increasing impact parameter. The sticking probability increases with energy density (impact energy per contact area). We also observe collisions of aggregates that were formed by a previous sticking of two larger aggregates. Partners of these aggregates can be detached by a second collision with a probability of on average 19.8 \\pm 4.0%. The measured accretion efficiencies are remarkably high compared to other experimental results. We at...

  9. Surfactant-assisted growth of anodic nanoporous niobium oxide with a grained surface

    International Nuclear Information System (INIS)

    Nanoporous niobium oxide film with a maximum thickness of 520 nm was prepared by anodizing niobium in a mixture of 1 wt% HF, 1 M H3PO4, and a small amount of Sodium Dodecyl Sulfate (SDS) surfactant. The porosity of the anodic niobium oxide prepared without SDS is irregular with the surface of the oxide suggesting a grained surface pattern rather than an ordered porous structure. A proper amount of SDS addition can prepare a pore arrangement with stripe patterns. The pore depth and surface pattern were strongly affected by the concentration of SDS and bath temperature. We found that the addition of SDS surfactant facilitated improvement in the chemical resistance of niobium oxide, leading to the formation of pores with a longer length compared to those prepared without a SDS surfactant. This can be in part ascribed to the protection of the surface by the physical adsorption of SDS on the surface due to a charge-charge interaction and be in part attributed to the formation of Nb=O bonding on the outermost oxide layer by SDS. When anodization was carried out for 4 h, the surface dissolution of niobium oxide was observed, which means that the maximum tolerance time against chemical dissolution was less than 4 h.

  10. Preparation of ZrB{sub 2}-based nanocomposites with limited grain growth by means of low-temperature hot-pressing using Cu additive

    Energy Technology Data Exchange (ETDEWEB)

    He, Rujie; Zhang, Xinghong; Hu, Ping; Han, Wenbo [Harbin Institute of Technology (China). National Key Lab. of Science and Technology on Advanced Composites in Special Environments

    2013-10-15

    The purpose of the present study is to prepare ZrB{sub 2}-based nanocomposites with limited or no obvious grain growth. For ZrB{sub 2} nanoparticles, the densification on-set temperature was about 1300 C, whereas the obvious grain growth on-set temperature for ZrB{sub 2} nanoparticles was found to be about 1500 C. Therefore, there was a temperature 'window' 1300-1500 C where ZrB{sub 2} nanoparticles could be densified with limited or no grain growth. In this study, densification of ZrB{sub 2}-based nanocomposite was finally realized by means of low-temperature hot-pressing at 1450 C for 60 min under a uniaxial pressure of 30 MPa using Cu as a sintering additive. After hot-pressing, the grain growth of ZrB{sub 2} nanoparticles was greatly suppressed, and the average grain size for ZrB{sub 2} was only 310 nm. The microstructure and mechanical properties were examined, and the flexural strength and fracture toughness were 472.8 {+-} 36.4 MPa and 12.4 {+-} 0.5M Pa . m{sup 1/2}, respectively. We believe this paper can lay the foundation for the preparation of ZrB{sub 2}-based nanocomposites. (orig.)

  11. Effect of Nano-Particle Addition on Grain Structure Evolution of Friction Stir-Processed Al 6061 During Postweld Annealing

    Science.gov (United States)

    Guo, Junfeng; Lee, Bing Yang; Du, Zhenglin; Bi, Guijun; Tan, Ming Jen; Wei, Jun

    2016-08-01

    The fabrication of nano-composites is challenging because uniform dispersion of nano-sized reinforcements in metallic substrate is difficult to achieve using powder metallurgy or liquid processing methods. In the present study, Al-based nano-composites reinforced with Al2O3 particles have been successfully fabricated using friction stir processing. The effects of nano-Al2O3 particle addition on grain structure evolution of friction stir-processed Al matrix during post-weld annealing were investigated. It was revealed that the pinning effect of Al2O3 particles retarded grain growth and completely prevented abnormal grain growth during postweld annealing at 470°C. However, abnormal grain growth can still occur when the composite material was annealed at 530°C. The mechanism involved in the grain structure evolution and the effect of nano-sized particle addition on the mechanical properties were discussed therein.

  12. Influence of second-phase particles on grain growth in AZ31 magnesium alloy during equal channel angular pressing by phase field simulation

    Science.gov (United States)

    He, Ri; Wang, Mingtao; Zhang, Xiangang; Yaping Zong, Bernie

    2016-06-01

    A phase-field model was established to simulate the refinement effect of different morphological factors of second-phase particles such as Al2O3 on the grain growth of AZ31 magnesium alloy during equal channel angular pressing (ECAP) in realistic spatiotemporal evolution. The simulation results agreed well with limited existing experimental data for the ECAP-processed AZ31 magnesium alloy and were consistent with the law of Zener. Simulations were performed to evaluate the influences of the fraction, size, distribution, and shape of incoherent second-phase particles. The simulation results showed that during high-temperature ECAP processes, the addition of 2 wt.% Al2O3 particles resulted in a strong refinement effect, reducing the grain size by 28.7% compared to that of the alloy without the particles. Nevertheless, when the fraction of particles was greater than 4 wt.%, adding more particles had little effect. In AZ31 Mg alloy, it was found that second-phase particles should have a critical size of 0.5–0.8 μm for the grain refinement effect to occur. If the size is smaller than the critical size, large particles will strongly hinder grain growth; in contrast, if the size is larger than the critical size, large particles will exhibit a weaker hindering effect than small particles. Moreover, the results showed that the refinement effect increased with increasing particle fraction located at grain boundaries with respect to the total particle content. However, the refinement effect was less pronounced when the fraction of particles located at boundaries was greater than 70%. Further simulations indicated that spherical second-phase particles hindered grain growth more than ellipsoid particles and much more than rod-shaped particles when the volume fraction of reinforcing particles was 2%. However, when the volume fraction was greater than 8%, rod-shaped particles best hindered grain growth, and spherical particles exhibited the weakest effect.

  13. Effect of Irrigation Timing on Root Zone Soil Temperature, Root Growth and Grain Yield and Chemical Composition in Corn

    Directory of Open Access Journals (Sweden)

    Xuejun Dong

    2016-05-01

    Full Text Available High air temperatures during the crop growing season can reduce harvestable yields in major agronomic crops worldwide. Repeated and prolonged high night air temperature stress may compromise plant growth and yield. Crop varieties with improved heat tolerance traits as well as crop management strategies at the farm scale are thus needed for climate change mitigation. Crop yield is especially sensitive to night-time warming trends. Current studies are mostly directed to the elevated night-time air temperature and its impact on crop growth and yield, but less attention is given to the understanding of night-time soil temperature management. Delivering irrigation water through drip early evening may reduce soil temperature and thus improve plant growth. In addition, corn growers typically use high-stature varieties that inevitably incur excessive respiratory carbon loss from roots and transpiration water loss under high night temperature conditions. The main objective of this study was to see if root-zone soil temperature can be reduced through drip irrigation applied at night-time, vs. daytime, using three corn hybrids of different above-ground architecture in Uvalde, TX where day and night temperatures during corn growing season are above U.S. averages. The experiment was conducted in 2014. Our results suggested that delivering well-water at night-time through drip irrigation reduced root-zone soil temperature by 0.6 °C, increase root length five folds, plant height 2%, and marginally increased grain yield by 10%. However, irrigation timing did not significantly affect leaf chlorophyll level and kernel crude protein, phosphorous, fat and starch concentrations. Different from our hypothesis, the shorter, more compact corn hybrid did not exhibit a higher yield and growth as compared with taller hybrids. As adjusting irrigation timing would not incur an extra cost for farmers, the finding reported here had immediate practical implications for farm

  14. The influence of the recrystallization mechanisms and grain growth on the texture of a hot rolled AZ31 sheet during subsequent isochronal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Victoria-Hernandez, J., E-mail: jose.victoria-hernandez@hzg.de; Yi, S.; Bohlen, J.; Kurz, G.; Letzig, D.

    2014-12-15

    Highlights: • The rolling texture of a twin roll cast AZ31 shows broad off-basal orientations. • Prismatic and pyramidal slip, and secondary twins influence the rolling texture. • Discontinuous recrystallization is promoted in grains deformed by pyramidal slip. • Recovery and extended recovery are promoted in grains deformed by prismatic slip. • Fast growing grain with orientation close to (0 0 0 1) lead the formation of a basal texture. - Abstract: The texture development during isochronal annealing at 250, 300 and 350 °C for 30 min of a hot rolled Mg AZ31 sheet produced by twin-roll casting was studied in this work. It was found that the rolling texture shows some features that resemble the textures that develop in rolled Mg alloys with rare earth additions. During further heat treatment, special attention was given to the deformation and recrystallization mechanisms, and grain growth that control the texture development. It was found that at 250 and 300 °C extended recovery and discontinuous recrystallization influence the texture by generating strain free grains with off-basal orientation. Conversely, during annealing at 350 °C growth of grains with their c-axis close to the (0 0 0 1) leads to the formation of the well-known basal type texture.

  15. The influence of the recrystallization mechanisms and grain growth on the texture of a hot rolled AZ31 sheet during subsequent isochronal annealing

    International Nuclear Information System (INIS)

    Highlights: • The rolling texture of a twin roll cast AZ31 shows broad off-basal orientations. • Prismatic and pyramidal slip, and secondary twins influence the rolling texture. • Discontinuous recrystallization is promoted in grains deformed by pyramidal slip. • Recovery and extended recovery are promoted in grains deformed by prismatic slip. • Fast growing grain with orientation close to (0 0 0 1) lead the formation of a basal texture. - Abstract: The texture development during isochronal annealing at 250, 300 and 350 °C for 30 min of a hot rolled Mg AZ31 sheet produced by twin-roll casting was studied in this work. It was found that the rolling texture shows some features that resemble the textures that develop in rolled Mg alloys with rare earth additions. During further heat treatment, special attention was given to the deformation and recrystallization mechanisms, and grain growth that control the texture development. It was found that at 250 and 300 °C extended recovery and discontinuous recrystallization influence the texture by generating strain free grains with off-basal orientation. Conversely, during annealing at 350 °C growth of grains with their c-axis close to the (0 0 0 1) leads to the formation of the well-known basal type texture

  16. Polymer-Coated Urea Delays Growth and Accumulation of Key Nutrients in Aerobic Rice but Does Not Affect Grain Mineral Concentrations

    Directory of Open Access Journals (Sweden)

    Terry J. Rose

    2016-01-01

    Full Text Available Enhanced efficiency nitrogen (N fertilizers (EEFs may improve crop recovery of fertilizer-N, but there is evidence that some EEFs cause a lag in crop growth compared to growth with standard urea. Biomass and mineral nutrient accumulation was investigated in rice fertilized with urea, urea-3,4-dimethylpyrazole phosphate (DMPP and polymer-coated urea (PCU to determine whether any delays in biomass production alter the accumulation patterns, and subsequent grain concentrations, of key mineral nutrients. Plant growth and mineral accumulation and partitioning to grains did not differ significantly between plants fertilized with urea or urea-DMPP. In contrast, biomass accumulation and the accumulation of phosphorus, potassium, calcium, magnesium, copper, zinc and manganese were delayed during the early growth phase of plants fertilized with PCU. However, plants in the PCU treatment ultimately compensated for this by increasing growth and nutrient uptake during the latter vegetative stages so that no differences in biomass or nutrient accumulation generally existed among N fertilizer treatments at anthesis. Delayed biomass accumulation in rice fertilized with PCU does not appear to reduce the total accumulation of mineral nutrients, nor to have any impact on grain mineral nutrition when biomass and grain yields are equal to those of rice grown with urea or urea-DMPP.

  17. Burkholderia ambifaria and B. caribensis promote growth and increase yield in grain amaranth (Amaranthus cruentus and A. hypochondriacus) by improving plant nitrogen uptake.

    Science.gov (United States)

    Parra-Cota, Fannie I; Peña-Cabriales, Juan J; de Los Santos-Villalobos, Sergio; Martínez-Gallardo, Norma A; Délano-Frier, John P

    2014-01-01

    Grain amaranth is an emerging crop that produces seeds having high quality protein with balanced amino-acid content. However, production is restricted by agronomic limitations that result in yields that are lower than those normally produced by cereals. In this work, the use of five different rhizobacteria were explored as a strategy to promote growth and yields in Amaranthus hypochondriacus cv. Nutrisol and A. cruentus cv. Candil, two commercially important grain amaranth cultivars. The plants were grown in a rich substrate, high in organic matter, nitrogen (N), and phosphorus (P) and under greenhouse conditions. Burkholderia ambifaria Mex-5 and B. caribensis XV proved to be the most efficient strains and significantly promoted growth in both grain amaranth species tested. Increased grain yield and harvest index occurred in combination with chemical fertilization when tested in A. cruentus. Growth-promotion and improved yields correlated with increased N content in all tissues examined. Positive effects on growth also occurred in A. cruentus plants grown in a poor soil, even after N and P fertilization. No correlation between non-structural carbohydrate levels in roots of inoculated plants and growth promotion was observed. Conversely, gene expression assays performed at 3-, 5- and 7-weeks after seed inoculation in plants inoculated with B. caribensis XV identified a tissue-specific induction of several genes involved in photosynthesis, sugar- and N- metabolism and transport. It is concluded that strains of Burkholderia effectively promote growth and increase seed yields in grain amaranth. Growth promotion was particularly noticeable in plants grown in an infertile soil but also occurred in a well fertilized rich substrate. The positive effects observed may be attributed to a bio-fertilization effect that led to increased N levels in roots and shoots. The latter effect correlated with the differential induction of several genes involved in carbon and N metabolism

  18. Effects of ocean acidification driven by elevated CO2 on larval shell growth and abnormal rates of the venerid clam, Mactra veneriformis

    Science.gov (United States)

    Kim, Jee-Hoon; Yu, Ok Hwan; Yang, Eun Jin; Kang, Sung-Ho; Kim, Won; Choy, Eun Jung

    2016-03-01

    The venerid clam (Mactra veneriformis Reeve 1854) is one of the main cultured bivalve species in intertidal and shallow subtidal ecosystems along the west coast of Korea. To understand the effects of ocean acidification on the early life stages of Korean clams, we investigated shell growth and abnormality rates and types in the D-shaped, umbonate veliger, and pediveliger stages of the venerid clam M. veneriformis during exposure to elevated seawater pCO2. In particular, we examined abnormal types of larval shell morphology categorized as shell deformations, shell distortions, and shell fissures. Specimens were incubated in seawater equilibrated with bubbled CO2-enriched air at (400±25)×10-6 (ambient control), (800±25)×10-6 (high pCO2), or (1 200±28)×10-6 (extremely high pCO2), the atmospheric CO2 concentrations predicted for the years 2014, 2084, and 2154 (70-year intervals; two human generations), respectively, in the Representative Concentration Pathway (RCP) 8.5 scenario. The mean shell lengths of larvae were significantly decreased in the high and extremely high pCO2 groups compared with the ambient control groups. Furthermore, under high and extremely high pCO2 conditions, the cultures exhibited significantly increased abundances of abnormal larvae and increased severity of abnormalities compared with the ambient control. In the umbonate veliger stage of the experimental larvae, the most common abnormalities were shell deformations, distortions, and fissures; on the other hand, convex hinges and mantle protuberances were absent. These results suggest that elevated CO2 exerts an additional burden on the health of M. veneriformis larvae by impairing early development.

  19. Constitutive expression of CaPLA1 conferred enhanced growth and grain yield in transgenic rice plants.

    Science.gov (United States)

    Park, Ki Youl; Kim, Eun Yu; Seo, Young Sam; Kim, Woo Taek

    2016-03-01

    Phospholipids are not only important components of cell membranes, but participate in diverse processes in higher plants. In this study, we generated Capsicum annuum phospholipiase A1 (CaPLA1) overexpressing transgenic rice (Oryza sativa L.) plants under the control of the maize ubiquitin promoter. The T4 CaPLA1-overexpressing rice plants (Ubi:CaPLA1) had a higher root:shoot mass ratio than the wild-type plants in the vegetative stage. Leaf epidermal cells from transgenic plants had more cells than wild-type plants. Genes that code for cyclin and lipid metabolic enzymes were up-regulated in the transgenic lines. When grown under typical paddy field conditions, the transgenic plants produced more tillers, longer panicles and more branches per panicle than the wild-type plants, all of which resulted in greater grain yield. Microarray analysis suggests that gene expressions that are related with cell proliferation, lipid metabolism, and redox state were widely altered in CaPLA1-overexpressing transgenic rice plants. Ubi:CaPLA1 plants had a reduced membrane peroxidation state, as determined by malondialdehyde and conjugated diene levels and higher peroxidase activity than wild-type rice plants. Furthermore, three isoprenoid synthetic genes encoding terpenoid synthase, hydroxysteroid dehydrogenase and 3-hydroxy-3-methyl-glutaryl-CoA reductase were up-regulated in CaPLA1-overexpressing plants. We suggest that constitutive expression of CaPLA1 conferred increased grain yield with enhanced growth in transgenic rice plants by alteration of gene activities related with cell proliferation, lipid metabolism, membrane peroxidation state and isoprenoid biosynthesis. PMID:26803502

  20. Antagonistic activity of Ocimum sanctum L. essential oil on growth and zearalenone production by Fusarium graminearum in maize grains

    Directory of Open Access Journals (Sweden)

    Naveen Kumar eKalagatur

    2015-09-01

    Full Text Available The present study was aimed to establish the antagonistic effects of Ocimum sanctum L. essential oil (OSEO on growth and zearalenone (ZEA production of Fusarium graminearum. GC-MS chemical profiling of OSEO revealed the existence of 43 compounds and the major compound was found to be eugenol (34.7%. DPPH free radical scavenging activity (IC50 of OSEO was determined to be 8.5µg/mL. Minimum inhibitory concentration (MIC and minimum fungicidal concentration (MFC of OSEO on F. graminearum were recorded as 1250 µg/mL and 1800 µg/mL, respectively. Scanning electron microscope observations showed significant micro morphological damage in OSEO exposed mycelia and spores compared to untreated control culture. Quantitative UHPLC studies revealed that OSEO negatively effected the production of ZEA; the concentration of toxin production was observed to be insignificant at 1500 µg/mL concentration of OSEO. On other hand ZEA concentration was quantified as 3.23 µg/mL in OSEO untreated control culture. Reverse transcriptase qPCR analysis of ZEA metabolic pathway genes (PKS4 and PKS13 revealed that increase in OSEO concentration (250 µg/mL to 1500 µg/mL significantly downregulated the expression of PKS4 and PKS13. These results were in agreement with the artificially contaminated maize grains as well. In conlusion, the antifungal and antimycotoxic effects of OSEO on F. graminearum in the present study reiterated that, the essential oil of O. sanctum could be a promising herbal fungicide in food processing industries as well as grain storage centers.

  1. Antagonistic activity of Ocimum sanctum L. essential oil on growth and zearalenone production by Fusarium graminearum in maize grains.

    Science.gov (United States)

    Kalagatur, Naveen K; Mudili, Venkataramana; Siddaiah, Chandranayaka; Gupta, Vijai K; Natarajan, Gopalan; Sreepathi, Murali H; Vardhan, Batra H; Putcha, Venkata L R

    2015-01-01

    The present study was aimed to establish the antagonistic effects of Ocimum sanctum L. essential oil (OSEO) on growth and zearalenone (ZEA) production of Fusarium graminearum. GC-MS chemical profiling of OSEO revealed the existence of 43 compounds and the major compound was found to be eugenol (34.7%). DPPH free radical scavenging activity (IC50) of OSEO was determined to be 8.5 μg/mL. Minimum inhibitory concentration and minimum fungicidal concentration of OSEO on F. graminearum were recorded as 1250 and 1800 μg/mL, respectively. Scanning electron microscope observations showed significant micro morphological damage in OSEO exposed mycelia and spores compared to untreated control culture. Quantitative UHPLC studies revealed that OSEO negatively effected the production of ZEA; the concentration of toxin production was observed to be insignificant at 1500 μg/mL concentration of OSEO. On other hand ZEA concentration was quantified as 3.23 μg/mL in OSEO untreated control culture. Reverse transcriptase qPCR analysis of ZEA metabolic pathway genes (PKS4 and PKS13) revealed that increase in OSEO concentration (250-1500 μg/mL) significantly downregulated the expression of PKS4 and PKS13. These results were in agreement with the artificially contaminated maize grains as well. In conlusion, the antifungal and antimycotoxic effects of OSEO on F. graminearum in the present study reiterated that, the essential oil of O. sanctum could be a promising herbal fungicide in food processing industries as well as grain storage centers. PMID:26388846

  2. Computer simulation model for coupled grain growth and Ostwald ripening -- Application to Al2O3-ZrO2 two-phase systems

    International Nuclear Information System (INIS)

    A kinetic model based on generalized continuum time-dependent Ginzburg-Landau (TDGL) equations is proposed for studying coupled grain growth and Ostwald ripening in multiphase systems. In this model, an arbitrary multiphase microstructure is described by many orientation field variables which represent crystallographic orientations of grains in each phase and by n - 1 composition field variables which distinguish the compositional differences among n phases. Microstructural development during simultaneous grain growth and Ostwald ripening is predicted by the temporal evolution of these field variables by numerically solving the TDGL equations. A particular example, Al2O3-ZrO2 particulate composite, was considered. The effects of the volume fraction of ZrO2 on the microstructural features and their evolution were studied and compared to experimental observations and previous thermodynamic analysis

  3. 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.

  4. Polymer-Coated Urea Delays Growth and Accumulation of Key Nutrients in Aerobic Rice but Does Not Affect Grain Mineral Concentrations

    OpenAIRE

    Terry J. Rose

    2016-01-01

    Enhanced efficiency nitrogen (N) fertilizers (EEFs) may improve crop recovery of fertilizer-N, but there is evidence that some EEFs cause a lag in crop growth compared to growth with standard urea. Biomass and mineral nutrient accumulation was investigated in rice fertilized with urea, urea-3,4-dimethylpyrazole phosphate (DMPP) and polymer-coated urea (PCU) to determine whether any delays in biomass production alter the accumulation patterns, and subsequent grain concentrations, of key minera...

  5. Enhancement effects of dietary wheat distiller's dried grains with solubles on growth, immunology, and resistance to Edwardsiella ictaluri challenge of channel catfish, Ictalurus punctatus

    Science.gov (United States)

    This study evaluated the effects of the inclusion of wheat distiller’s dried grains with solubles (WDDGS) at levels of 0 (control), 10, 20, 30 and 40% without (diets 2-5) and with (diets 6-9) lysine supplementation, as substitutes of soybean meal and corn meal mixture on growth, body composition, he...

  6. Growth Response and Resistance to Streptococcus iniae of Nile Tilapia Oreochromis niloticus Fed Diets Containing Distiller’s Dried Grains with Solubles

    Science.gov (United States)

    This study was conducted to evaluate the effect of dietary levels of distiller’s dried grains with solubles (DDGS) on growth performance, body composition, hematology, immune response and resistance of Nile tilapia to Streptococcus iniae challenge. Five isocaloric diets containing DDGS at levels of ...

  7. Densification and Grain Growth during Early-stage Sintering of Ce0.9Gd0.1O1.95-δ in Reducing Atmosphere

    DEFF Research Database (Denmark)

    He, Zeming; Yuan, Hao; Glasscock, Julie;

    2010-01-01

    The present work investigates the processes of densification and grain growth of Ce0.9Gd0.1O1.95-δ (CGO10) during sintering in reducing atmosphere. Sintering variables were experimentally characterized and analyzed using defect chemistry and sintering constitutive laws. Based on the achieved...

  8. Effects of dietary electrolyte balance and molasses in diets with corn-based distiller's dried grains with solubles on growth performance in nursery and finishing pigs

    Science.gov (United States)

    Two assays were conducted to determine the effects of dietary electrolyte balance dEB) and molasses in diets with corn-based distiller’s dried grains with solubles (DDGS, Sioux River Ethanol, Hudson, SD) on growth performance of nursery and finishing pigs. For the first experiment, 126 nursery pigs ...

  9. Microwave sintering of nano-grained zinc ferrite and its grain growth kinetics%微波法制备纳米铁酸锌及其晶粒生长动力学

    Institute of Scientific and Technical Information of China (English)

    张瑞妮; 张帅国; 武蒙蒙; 上官炬; 米杰

    2015-01-01

    纳米铁酸锌广泛应用于催化和材料领域,为了避免传统焙烧法高耗能的缺点,本实验选用高效微波法制备纳米铁酸锌,并与常规焙烧进行对比,研究了铁酸锌晶粒生长动力学.采用FTIR、XRD和SEM对样品进行表征.结果表明,相同焙烧温度和焙烧时间下,微波法制备的铁酸锌比常规制备的样品结晶度高,颗粒大小更均匀.通过谢乐公式计算不同温度下铁酸锌粒径得出,焙烧温度低于 500℃时,焙烧方式对铁酸锌粒径影响较大;纳米铁酸锌晶粒生长动力学研究显示,微波焙烧时晶粒的平均生长指数为 9.66,低于常规焙烧生长指数(10.6),表明微波焙烧时晶粒的平均生长速率较高,有利于晶粒生长;同时,微波晶粒生长平均活化能为122.1kJ/mol,远低于常规焙烧平均活化能(179.4kJ/mol),说明微波可以降低晶粒生长活化能,且微波的"非热效应"影响晶粒的生长.%The nano-grained zinc ferrite was prepared by high-efficiency microwave sintering,which eliminated the drawback of high energy consumption in traditional sintering. The grain growth kinetics of zinc ferrite by both microwave and traditional sintering were studied. The Fourier transforms infrared spectra,X-ray diffraction and scanning electron microscope were used to characterize the microstructure of the zinc ferrite. Our results showed that zinc ferrite samples obtained by microwave sintering were of better-crystallized phase and more homogeneous grain size distribution than those by the traditional sintering. The particle size of zinc ferrite was calculated by the Scherrer equation. Calcinations method has a significant impact on the grain size when the calcinations temperature is lower than 500℃. The kinetic studies of grain growth showed that the average exponent value of grain growth was 9.66 for the nano-grained zinc ferrite sintered by microwave,lower than that of the traditional sintered samples. It indicates that microwave

  10. Facile solvothermal synthesis of abnormal growth of one-dimensional ZnO nanostructures by ring-opening reaction of polyvinylpyrrolidone

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Facile solvothermal synthesis of ZnO nanostructures in super high alkaline alcoholic condition. • The exact role and chemical transformations of PVP in solvothermal synthesis of ZnO nanostructures was revealed. • Mechanism of abnormal growth of ZnO nanopyramids was proposed based on ring-opening reaction of PVP. - Abstract: Abnormal growth of one-dimensional (1-D) ZnO nanostructures (NSs) have been accomplished with the assistance of polyvinylpyrrolidone (PVP) under a super high alkaline alcoholic solvothermal condition. The products were characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (1H NMR) spectroscopy. The effect of synthetic conditions, such as reaction temperature and the addition of PVP, on the morphologies of ZnO products were investigated. The results show that PVP molecules had the significant role in the transformation of morphologies of ZnO NSs ranging from nanorods, nanoparticles to pyramids, as well as flower-like assembly features. The possible growth mechanism of ZnO pyramids was proposed based on ring-opening reaction of PVP

  11. Coarse-grained molecular simulation of epidermal growth factor receptor protein tyrosine kinase multi-site self-phosphorylation.

    Directory of Open Access Journals (Sweden)

    John G Koland

    2014-01-01

    Full Text Available Upon the ligand-dependent dimerization of the epidermal growth factor receptor (EGFR, the intrinsic protein tyrosine kinase (PTK activity of one receptor monomer is activated, and the dimeric receptor undergoes self-phosphorylation at any of eight candidate phosphorylation sites (P-sites in either of the two C-terminal (CT domains. While the structures of the extracellular ligand binding and intracellular PTK domains are known, that of the ∼225-amino acid CT domain is not, presumably because it is disordered. Receptor phosphorylation on CT domain P-sites is critical in signaling because of the binding of specific signaling effector molecules to individual phosphorylated P-sites. To investigate how the combination of conventional substrate recognition and the unique topological factors involved in the CT domain self-phosphorylation reaction lead to selectivity in P-site phosphorylation, we performed coarse-grained molecular simulations of the P-site/catalytic site binding reactions that precede EGFR self-phosphorylation events. Our results indicate that self-phosphorylation of the dimeric EGFR, although generally believed to occur in trans, may well occur with a similar efficiency in cis, with the P-sites of both receptor monomers being phosphorylated to a similar extent. An exception was the case of the most kinase-proximal P-site-992, the catalytic site binding of which occurred exclusively in cis via an intramolecular reaction. We discovered that the in cis interaction of P-site-992 with the catalytic site was facilitated by a cleft between the N-terminal and C-terminal lobes of the PTK domain that allows the short CT domain sequence tethering P-site-992 to the PTK core to reach the catalytic site. Our work provides several new mechanistic insights into the EGFR self-phosphorylation reaction, and demonstrates the potential of coarse-grained molecular simulation approaches for investigating the complexities of self-phosphorylation in

  12. Hormonal growth-promotant effects on grain-fed cattle maintained under different environments

    Science.gov (United States)

    Gaughan, J. B.; Kreikemeier, W. M.; Mader, T. L.

    2005-07-01

    Six steers (3/4 Charolais×1/4 Brahman) (mean body weight 314±27 kg) and six spayed heifers (3/5 Shorthorn×2/5 Red Angus) (mean body weight 478±30 kg) were used to determine the effects of climatic conditions and hormone growth promotants (HGP) on respiration rate (RR; breaths/min), pulse rate (beats/min), rectal temperature (RT; °C), and heat production (HP; kJ). Cattle were exposed to the following climatic conditions prior to implantation with a HGP and then again 12 days after implantation: 2 days of thermoneutral conditions (TNL) [21.9±0.9°C ambient temperature (TA) and 61.7±22.1% relative humidity (RH)] then 2 days of hot conditions [HOT; 29.2±4°C (TA) and 78.3±13.2% (RH)], then TNL for 3 days and then 2 days of cold conditions [COLD; 17.6±0.9°C (TA) and 63.4±1.8% (RH); cattle were wet during this treatment]. The HGP implants used were: estrogenic implant (E), trenbolone acetate implant (TBA), or both (ET). Both prior to and following administration of HGP, RRs were lower (P0.5°C greater (P0.8°C higher than for the heifers, while under TNL and HOT, RTs of steers were 0.2 0.35°C higher than those of heifers. Prior to implantation, HP per hour and per unit of metabolic body weight was higher (P<0.05) for cattle exposed to hot conditions, when compared to HP on cold days. After implantation, HP was greater (P<0.05) on hot days than on cold days. Under TNL, ET cattle had the lowest HP and greatest feed intake. On hot days, E cattle had the lowest HP, and the highest RT; therefore, if the potential exists for cattle death from heat episodes, the use of either TBA or ET may be preferred. Under cold conditions HP was similar among implant groups.

  13. The effect of heat treatment and thermal spray processes on the grain growth of nanostructured composite CoNiCrAlY/YSZ powders

    International Nuclear Information System (INIS)

    This research investigated thermal stability of mechanically milled MCrAlY/YSZ composites during heat treatment and high velocity oxy-fuel (HVOF) thermal spray processes. MCrAlY powder was mixed with 5%, 10% and 15% YSZ and then milled for 12 and 24 h. A powder without YSZ reinforcement ball was milled for 12 and 24 h too. The composite powders were annealed for 10 h at 1273 K to investigate thermal stability. Nanocrystalline and commercial powders were deposited on Inconel-617 substrate using the HVOF process. The morphology and thermal stability of mechanically milled and heat treated powders and coatings were investigated using X-ray diffractometry, scanning electron microscopy (SEM) and optical microscopy (OM). It was found that the increase in milling time resulted in the uniform distribution of reinforcements in the γ phase matrix. The uniform distribution of reinforcements caused reduction in grain growth during heat treatment process. On the other hand, increasing YSZ percentage decreased grain growth, but when the YSZ amount exceeded 10%, the ceramic reinforcements could not prevent the grain growth of nanostructure powders. The heat absorbed by nanostructured powders during thermal spraying process resulted in the grain growth of the γ-phase, but due to the presence of YSZ reinforcement, the grain growth was very lower than that of unreinforced coatings. It could be suggested that nanostructure coating formed due to thermo mechanical phenomena occurred in commercial powder particles during thermal spray process. - Highlights: • CoNiCrAlY/YSZ composite. • Nanostructure powder. • Heat treatment of CoNiCrAlY/YSZ

  14. The effect of heat treatment and thermal spray processes on the grain growth of nanostructured composite CoNiCrAlY/YSZ powders

    Energy Technology Data Exchange (ETDEWEB)

    Tahari, Mostafa, E-mail: fa.tahari@yahoo.com [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Department of Engineering, Esfarayen University of Technology, Esfarayen-North Khorasan 96619-98195 (Iran, Islamic Republic of); Shamanian, Morteza; Salehi, Mehdi [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2015-10-15

    This research investigated thermal stability of mechanically milled MCrAlY/YSZ composites during heat treatment and high velocity oxy-fuel (HVOF) thermal spray processes. MCrAlY powder was mixed with 5%, 10% and 15% YSZ and then milled for 12 and 24 h. A powder without YSZ reinforcement ball was milled for 12 and 24 h too. The composite powders were annealed for 10 h at 1273 K to investigate thermal stability. Nanocrystalline and commercial powders were deposited on Inconel-617 substrate using the HVOF process. The morphology and thermal stability of mechanically milled and heat treated powders and coatings were investigated using X-ray diffractometry, scanning electron microscopy (SEM) and optical microscopy (OM). It was found that the increase in milling time resulted in the uniform distribution of reinforcements in the γ phase matrix. The uniform distribution of reinforcements caused reduction in grain growth during heat treatment process. On the other hand, increasing YSZ percentage decreased grain growth, but when the YSZ amount exceeded 10%, the ceramic reinforcements could not prevent the grain growth of nanostructure powders. The heat absorbed by nanostructured powders during thermal spraying process resulted in the grain growth of the γ-phase, but due to the presence of YSZ reinforcement, the grain growth was very lower than that of unreinforced coatings. It could be suggested that nanostructure coating formed due to thermo mechanical phenomena occurred in commercial powder particles during thermal spray process. - Highlights: • CoNiCrAlY/YSZ composite. • Nanostructure powder. • Heat treatment of CoNiCrAlY/YSZ.

  15. Dust properties and disk structure of evolved protoplanetary disks in Cep OB2: Grain growth, settling, gas and dust mass, and inside-out evolution

    CERN Document Server

    Sicilia-Aguilar, Aurora; Dullemond, Cornelis P; Patel, Nimesh; Juhász, Attila; Bouwman, Jeroen; Sturm, Bernhard

    2011-01-01

    We present Spitzer/IRS spectra of 31 TTS and IRAM/1.3mm observations for 34 low- and intermediate-mass stars in the Cep OB2 region. Including our previously published data, we analyze 56 TTS and the 3 intermediate-mass stars with silicate features in Tr 37 (~4 Myr) and NGC 7160 (~12 Myr). The silicate emission features are well reproduced with a mixture of amorphous (with olivine, forsterite, and silica stoichiometry) and crystalline grains (forsterite, enstatite). We explore grain size and disk structure using radiative transfer disk models, finding that most objects have suffered substantial evolution (grain growth, settling). About half of the disks show inside-out evolution, with either dust-cleared inner holes or a radially-dependent dust distribution, typically with larger grains and more settling in the innermost disk. The typical strong silicate features require nevertheless the presence of small dust grains, and could be explained by differential settling according to grain size, anomalous dust distr...

  16. Whole-plant dynamic system of nitrogen use for vegetative growth and grain filling in rice plants (Oryza sativa L. as revealed through the production of 350 grains from a germinated seed over 150 days: a review and synthesis

    Directory of Open Access Journals (Sweden)

    Tadakatsu Yoneyama

    2016-08-01

    Full Text Available A single germinated rice (Oryza sativa L seed can produce 350 grains with the sequential development of 15 leaves on the main stem and 7 ‒ 10 leaves on 4 productive tillers (forming 5 panicles in total, using nitrogen (N taken up from the environment over a 150-day growing season. Nitrogen travels from uptake sites to the grain through growing organ-directed cycling among sequentially developed organs. Over the past 40 years, the dynamic system for N allocation during vegetative growth and grain filling has been elucidated through studies on N and 15N transport as well as enzymes and transporters involved. In this review, we synthesize the information obtained in these studies along the following main points: (1 During vegetative growth before grain-filling, about half of the total N in the growing organs, including young leaves, tillers, root tips and differentiating panicles is supplied via phloem from mature source organs such as leaves and roots, after turnover and remobilization of proteins, whereas the other half is newly taken up and supplied via xylem, with an efficient xylem-to-phloem transfer at stem nodes. Thus, the growth of new organs depends equally on both N sources. (2 A large fraction (as much as 80% of the grain N is derived largely from mature organs such as leaves and stems by degradation, including the autophagy pathway of chloroplast proteins (e.g., Rubisco. (3 Mobilized proteinogenic amino acids, including arginine, lysine, proline and valine, are derived mainly from protein degradation, with amino acid transporters playing a role in transferring these amino acids across cell membranes of source and sink organs, and enabling their efficient reutilization in the latter. On the other hand, amino acids such as glutamine, glutamic acid, γ-amino butyric acid, aspartic acid, and alanine are produced by assimilation of newly taken up N by roots and transported via xylem and phloem. The formation of 350 filled grains over 50

  17. Whole-Plant Dynamic System of Nitrogen Use for Vegetative Growth and Grain Filling in Rice Plants (Oryza sativa L.) as Revealed through the Production of 350 Grains from a Germinated Seed Over 150 Days: A Review and Synthesis.

    Science.gov (United States)

    Yoneyama, Tadakatsu; Tanno, Fumio; Tatsumi, Jiro; Mae, Tadahiko

    2016-01-01

    A single germinated rice (Oryza sativa L) seed can produce 350 grains with the sequential development of 15 leaves on the main stem and 7-10 leaves on four productive tillers (forming five panicles in total), using nitrogen (N) taken up from the environment over a 150-day growing season. Nitrogen travels from uptake sites to the grain through growing organ-directed cycling among sequentially developed organs. Over the past 40 years, the dynamic system for N allocation during vegetative growth and grain filling has been elucidated through studies on N and (15)N transport as well as enzymes and transporters involved. In this review, we synthesize the information obtained in these studies along the following main points: (1) During vegetative growth before grain-filling, about half of the total N in the growing organs, including young leaves, tillers, root tips and differentiating panicles is supplied via phloem from mature source organs such as leaves and roots, after turnover and remobilization of proteins, whereas the other half is newly taken up and supplied via xylem, with an efficient xylem-to-phloem transfer at stem nodes. Thus, the growth of new organs depends equally on both N sources. (2) A large fraction (as much as 80%) of the grain N is derived largely from mature organs such as leaves and stems by degradation, including the autophagy pathway of chloroplast proteins (e.g., Rubisco). (3) Mobilized proteinogenic amino acids (AA), including arginine, lysine, proline and valine, are derived mainly from protein degradation, with AA transporters playing a role in transferring these AAs across cell membranes of source and sink organs, and enabling their efficient reutilization in the latter. On the other hand, AAs such as glutamine, glutamic acid, γ-amino butyric acid, aspartic acid, and alanine are produced by assimilation of newly taken up N by roots and and transported via xylem and phloem. The formation of 350 filled grains over 50 days during the

  18. A novel, two-step top seeded infiltration and growth process for the fabrication of single grain, bulk (RE)BCO superconductors

    Science.gov (United States)

    Namburi, Devendra K.; Shi, Yunhua; Palmer, Kysen G.; Dennis, Anthony R.; Durrell, John H.; Cardwell, David A.

    2016-09-01

    A fundamental requirement of the fabrication of high performing, (RE)-Ba-Cu-O bulk superconductors is achieving a single grain microstructure that exhibits good flux pinning properties. The top seeded melt growth (TSMG) process is a well-established technique for the fabrication of single grain (RE)BCO bulk samples and is now applied routinely by a number of research groups around the world. The introduction of a buffer layer to the TSMG process has been demonstrated recently to improve significantly the general reliability of the process. However, a number of growth-related defects, such as porosity and the formation of micro-cracks, remain inherent to the TSMG process, and are proving difficult to eliminate by varying the melt process parameters. The seeded infiltration and growth (SIG) process has been shown to yield single grain samples that exhibit significantly improved microstructures compared to the TSMG technique. Unfortunately, however, SIG leads to other processing challenges, such as the reliability of fabrication, optimisation of RE2BaCuO5 (RE-211) inclusions (size and content) in the sample microstructure, practical oxygenation of as processed samples and, hence, optimisation of the superconducting properties of the bulk single grain. In the present paper, we report the development of a near-net shaping technique based on a novel two-step, buffer-aided top seeded infiltration and growth (BA-TSIG) process, which has been demonstrated to improve greatly the reliability of the single grain growth process and has been used to fabricate successfully bulk, single grain (RE)BCO superconductors with improved microstructures and superconducting properties. A trapped field of ˜0.84 T and a zero field current density of 60 kA cm-2 have been measured at 77 K in a bulk, YBCO single grain sample of diameter 25 mm processed by this two-step BA-TSIG technique. To the best of our knowledge, this value of trapped field is the highest value ever reported for a sample

  19. A novel, two-step top seeded infiltration and growth process for the fabrication of single grain, bulk (RE)BCO superconductors

    Science.gov (United States)

    Namburi, Devendra K.; Shi, Yunhua; Palmer, Kysen G.; Dennis, Anthony R.; Durrell, John H.; Cardwell, David A.

    2016-09-01

    A fundamental requirement of the fabrication of high performing, (RE)–Ba–Cu–O bulk superconductors is achieving a single grain microstructure that exhibits good flux pinning properties. The top seeded melt growth (TSMG) process is a well-established technique for the fabrication of single grain (RE)BCO bulk samples and is now applied routinely by a number of research groups around the world. The introduction of a buffer layer to the TSMG process has been demonstrated recently to improve significantly the general reliability of the process. However, a number of growth-related defects, such as porosity and the formation of micro-cracks, remain inherent to the TSMG process, and are proving difficult to eliminate by varying the melt process parameters. The seeded infiltration and growth (SIG) process has been shown to yield single grain samples that exhibit significantly improved microstructures compared to the TSMG technique. Unfortunately, however, SIG leads to other processing challenges, such as the reliability of fabrication, optimisation of RE2BaCuO5 (RE-211) inclusions (size and content) in the sample microstructure, practical oxygenation of as processed samples and, hence, optimisation of the superconducting properties of the bulk single grain. In the present paper, we report the development of a near-net shaping technique based on a novel two-step, buffer-aided top seeded infiltration and growth (BA-TSIG) process, which has been demonstrated to improve greatly the reliability of the single grain growth process and has been used to fabricate successfully bulk, single grain (RE)BCO superconductors with improved microstructures and superconducting properties. A trapped field of ∼0.84 T and a zero field current density of 60 kA cm‑2 have been measured at 77 K in a bulk, YBCO single grain sample of diameter 25 mm processed by this two-step BA-TSIG technique. To the best of our knowledge, this value of trapped field is the highest value ever reported for a

  20. Large Perovskite Grain Growth in Low-Temperature Solution-Processed Planar p-i-n Solar Cells by Sodium Addition.

    Science.gov (United States)

    Bag, Santanu; Durstock, Michael F

    2016-03-01

    Thin-film p-i-n type planar heterojunction perovskite solar cells have the advantage of full low temperature solution processability and can, therefore, be adopted in roll-to-roll production and flexible devices. One of the main challenges with these devices, however, is the ability to finely control the film morphology during the deposition and crystallization of the perovskite layer. Processes suitable for optimization of the perovskite layer film morphology with large grains are highly desirable for reduced recombination of charge carriers. Here, we show how uniform thin films with micron size perovskite grains can be made through the use of a controlled amount of sodium ions in the precursor solution. Large micrometer-size CH3NH3PbI3 perovskite grains are formed during low-temperature thin-film growth by adding sodium ions to the PbI2 precursor solution in a two-step interdiffusion process. By adjusting additive concentration, film morphologies were optimized and the fabricated p-i-n planar perovskite-PCBM solar cells showed improved power conversion efficiences (an average of 3-4% absolute efficiency enhancement) compared to the nonsodium based devices. Overall, the additive enhanced grain growth process helped to reach a high 14.2% solar cell device efficiency with low hysteresis. This method of grain growth is quite general and provides a facile way to fabricate large-grained CH3NH3PbI3 on any arbitrary surface by an all solution-processed route. PMID:26862869

  1. Large Perovskite Grain Growth in Low-Temperature Solution-Processed Planar p-i-n Solar Cells by Sodium Addition.

    Science.gov (United States)

    Bag, Santanu; Durstock, Michael F

    2016-03-01

    Thin-film p-i-n type planar heterojunction perovskite solar cells have the advantage of full low temperature solution processability and can, therefore, be adopted in roll-to-roll production and flexible devices. One of the main challenges with these devices, however, is the ability to finely control the film morphology during the deposition and crystallization of the perovskite layer. Processes suitable for optimization of the perovskite layer film morphology with large grains are highly desirable for reduced recombination of charge carriers. Here, we show how uniform thin films with micron size perovskite grains can be made through the use of a controlled amount of sodium ions in the precursor solution. Large micrometer-size CH3NH3PbI3 perovskite grains are formed during low-temperature thin-film growth by adding sodium ions to the PbI2 precursor solution in a two-step interdiffusion process. By adjusting additive concentration, film morphologies were optimized and the fabricated p-i-n planar perovskite-PCBM solar cells showed improved power conversion efficiences (an average of 3-4% absolute efficiency enhancement) compared to the nonsodium based devices. Overall, the additive enhanced grain growth process helped to reach a high 14.2% solar cell device efficiency with low hysteresis. This method of grain growth is quite general and provides a facile way to fabricate large-grained CH3NH3PbI3 on any arbitrary surface by an all solution-processed route.

  2. Bulk tungsten in the JET divertor: Potential influence of the exhaustion of ductility and grain growth on the lifetime

    Science.gov (United States)

    Mertens, Ph.; Thompson, V.; Matthews, G. F.; Nicolai, D.; Pintsuk, G.; Riccardo, V.; Devaux, S.; Sieglin, B.; JET-EFDA contributors

    2013-07-01

    The divertor of the ITER-like Wall in JET currently includes a solid tungsten row for the outer strike point. The use of plasma-facing tungsten in fusion devices is limited by its brittleness in the low temperature domain (arbitrarily ˜TW 1200 °C). In the absence of active cooling, an extreme case of thermal cycling is represented by the situation in JET: the plasma-facing surface of the bulk tungsten tile experiences cyclic excursions from 200 °C to about 2000 °C. Thermal fatigue for impact factors of 11-24 MW m-2 s0.5 is investigated with a Manson-Coffin model; tungsten properties come from production samples. Recrystallization is studied in metallographic cuts of tungsten lamellae identical to those installed in the torus which were exposed in the MARION facility to JET relevant heat fluxes for >300 pulses (Pdep ⩽ 9 MW/m2, angle of attack 6°). The calculations suggest that the number of high temperature cycles should be limited with appropriate budgeting, especially if the grain growth degrades material properties. Values for JET range from 150 to thousands of pulses depending on the temperatures reached.

  3. The tolerance of grain amaranth (Amaranthus cruentus L.) to defoliation during vegetative growth is compromised during flowering.

    Science.gov (United States)

    Vargas-Ortiz, Erandi; Délano-Frier, John Paul; Tiessen, Axel

    2015-06-01

    The biochemical processes underlying variations of tolerance are often accompanied by source-sink transitions affecting carbon (C) metabolism. We investigated the tolerance of Amaranthus cruentus L. to total mechanical defoliation through development and in different growing seasons. Defoliated A. cruentus recovered ∼80% of their above-ground biomass and ∼100% of grain yield compared to intact plants if defoliation occurred early during ontogeny, but could not compensate when defoliation occurred during flowering. Tolerance index was higher in the summer season (-0.3) than in the winter season (-0.7). Overall, defoliation tolerance was closely related to phosphoenolpyruvate carboxylase (PEPC) activity in leaves and the subsequent accumulation of starch (∼500 μmol/gDW) and sucrose (∼140 μmol/gDW) in stems and roots. Thus, A. cruentus accumulated sufficient C in roots and stem to allow branching and shoot re-growth after defoliation, but it only possessed sufficient C reserves to maintain <19% seed yield in the absence of new vegetative tissue. Seed size was larger during the warm season but it was not affected by foliar damage. Seed chemical composition was altered by defoliation at flowering. We conclude that A. cruentus defoliation tolerance depends on both, the re-allocation of starch from stem and roots, and the activation of dormant meristems before flowering to generate new photosynthetic capacity to sustain seed filling. PMID:25863889

  4. Smoke in the Pipe Nebula: dust emission and grain growth in the starless core FeSt 1-457

    CERN Document Server

    Forbrich, Jan; Lombardi, Marco; Roman-Zuñiga, Carlos; Alves, João

    2015-01-01

    (abridged) Methods: We derive maps of submillimeter dust optical depth and effective dust temperature from Herschel data that were calibrated against Planck. After calibration, we then fit a modified blackbody to the long-wavelength Herschel data, using the Planck-derived dust opacity spectral index beta, derived on scales of 30' (or ~1 pc). We use this model to make predictions of the submillimeter flux density at 850 micron, and we compare these in turn with APEX-Laboca observations. Results: A comparison of the submillimeter dust optical depth and near-infrared extinction data reveals evidence for an increased submillimeter dust opacity at high column densities, interpreted as an indication of grain growth in the inner parts of the core. Additionally, a comparison of the Herschel dust model and the Laboca data reveals that the frequency dependence of the submillimeter opacity, described by the spectral index beta, does not change. A single beta that is only slightly different from the Planck-derived value ...

  5. A Study on the Thermodynamics of Grain Growth in R.F. Magnetron Sputtered NiO Thin Films

    Directory of Open Access Journals (Sweden)

    I. Dhanya

    2013-01-01

    Full Text Available Postdeposition annealing of thin nickel films synthesized using R.F. magnetron sputtering technique is carried in this study. The XRD analysis indicates that annealing of the nickel films leads to the formation of nickel oxide with a preferential growth along (200 plane. The oxidation mechanism is observed with a phase transformation and results in polycrystalline NiO films. The surface morphology of the thin films was investigated by scanning electron microscopy (SEM and atomic force microscopy (AFM as a function of annealing temperature. The studies indicate the formation of well-defined grain boundaries due to agglomeration of nanocrystallites. The films annealed in the range 573–773 K are found to be porous. The optical transmission spectra of the films annealed at 773 K exhibit interference effects for photon energies below the fundamental absorption edge. The optical studies indicate the existence of direct interband transition across a bandgap of 3.7 eV in confirmation with earlier band structure calculations.

  6. Ultra-fine ferrite grain refinement by static re-crystallization of hot rolled vanadium micro-alloyed steels

    International Nuclear Information System (INIS)

    The phenomenon of ultrafine-grain refinement of ferrite during transformational grain refinement (TGR) followed by static re-crystallization of vanadium micro-alloyed steels was studied. A substantial grain refinement (2.8 mu m) was attained during TGR process by rolling at 900 deg. C. Cold rolling with 70% of reduction introduced strain, utilized for re-crystallization during annealing at different temperatures. Electron Backscattered Diffraction (EBSD) technique was employed to quantify the low angle grain boundaries (LAGB) and high angle grain boundaries (HAGB) spacings and results were correlated with hardness drops during annealing process. At higher annealing times and temperatures the vanadium precipitates restricted the process of grain growth probably due to effective dispersion strengthening. The abnormal grain growth during annealing, predicted previously for niobium steels, found absent in the present vanadium microalloyed steels. (author)

  7. Densification and grain growth during sintering of porous Ce0.9Gd0.1O1.95tape cast layers: A comprehensive study on heuristic methods

    DEFF Research Database (Denmark)

    Ni, De Wei; Schmidt, Cristine Grings; Teocoli, Francesca;

    2013-01-01

    The sintering behavior of porous Ce0.9Gd0.1O1.95(CGO10) tape cast layers was systematically investigated to establish fundamental kinetic parameters associated to densification and grain growth. Densification and grain growth were characterized by a set of different methods to determine the domin...

  8. A new seeding technique for the reliable fabrication of large, SmBCO single grains containing silver using top seeded melt growth

    Science.gov (United States)

    Shi, Y.-H.; Dennis, A. R.; Cardwell, D. A.

    2015-03-01

    Silver (Ag) is an established additive for improving the mechanical properties of single grain, (RE)Ba2Cu3O7-δ [(RE)BCO, RE = Sm, Gd and Y] bulk superconductors. The presence of Ag in the (RE)BCO bulk composition, however, typically reduces the melting temperature of the single crystal seed in the top seeded melt growth (TSMG) process, which complicates significantly the controlled nucleation and subsequent epitaxial growth of a single grain, which is essential for high field engineering applications. The reduced reliability of the seeding process in the presence of Ag is particularly acute for the SmBCO system, since the melting temperature of SmBCO is very close to that of the generic NdBCO(MgO) seed. SmBCO has a high superconducting transition temperature, Tc, and exhibits the most pronounced ‘peak’ effect at higher magnetic field of all materials in the family of (RE)BCO bulk superconductors and, therefore, has the greatest potential for use in practical applications (compared to GdBCO and YBCO, in particular). Development of an effective seeding process, therefore, is one of the major challenges of the TSMG process for the growth of large, high quantity single grain superconductors. In this paper, we report a novel technique that involves introducing a buffer layer between the seed crystal and the precursor pellet, primarily to inhibit the diffusion of Ag from the green body to the seed during melt processing in order to prevent the melting of the seed. The success rate of the seeding process using this technique is 100% for relatively small batches of samples. The superconducting properties, critical temperature, Tc, critical current density, Jc and trapped fields, of the single grains fabricated using the buffers are reported and the microstructures in the vicinity of the buffer of single grains fabricated by the modified technique are analysed to understand further the effects of buffers on the growth process of these technologically important

  9. KINETICS OF SECONDARY RECRYSTALLIZATION IN GRAIN-ORIENTED SILICON STEEL STUDIED BY HIGH-TEMPERATURE BACKGROUND

    OpenAIRE

    Iwasaki, Y.; Fujimoto, K

    1981-01-01

    Secondary recrystallization in grain-oriented silicon steel is studied by the high-temperature background damping. Abnormal grain growth involves an abrupt drop of the background. The temperatures of initiation and completion of the secondary recrystallization are, thus, determined for the same sample from the definite change in background with increasing temperature. The background measured on isothermal annealing yields a transposed sigmoidal curve consisting of three stages when plotted as...

  10. Secondary recrystallization behavior in the rolled columnar-grained Fe–Ga alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Chao; Li, Jiheng; Zhang, Wenlan; Bao, Xiaoqian; Gao, Xuexu, E-mail: gaox@skl.ustb.edu.cn

    2015-10-01

    The secondary recrystallization behavior with temperature increasing from 900 to 1080 °C was investigated in the rolled columnar-grained magnetostrictive Fe–Ga alloy sheets. The abnormal Goss grain growth occurred due to the inhibitory action of NbC in the Fe–Ga–0.1 at%NbC sheets. With the temperature increasing at a rate of 0.25 °C/min, the secondary recrystallization started below 950 °C. In addition to the S-induced surface energy effect, sulfur annealing also introduced a large number of S-rich and Nb-rich precipitates, which retarded the grain boundary migration on the surface. The abnormal grain growth was found to be restricted inside the sheet during the sulfur annealing process when the temperature was below 1000 °C, and a large amount of small island-like grains was remained on S-annealed sheets. After final Ar/H{sub 2} annealing processes, the S-rich precipitates and small island-like grains were eliminated, and sharp Goss orientation and high magnetostriction of 245 ppm were obtained in the final S-annealed sheets. - Highlights: • Secondary recrystallization started below 1000 °C in rolled Fe–Ga sheets. • Inhibition effect was introduced on the surfaces by sulfur annealing. • Abnormal Goss grains develop inside the sheets during sulfur annealing.

  11. Abnormalities of growth hormone release in response to human pancreatic growth hormone releasing factor (GRF (1-44) ) in acromegaly and hypopituitarism.

    OpenAIRE

    Wood, S M; Ch'ng, J L; Adams, E. F.; Webster, J D; Joplin, G F; Mashiter, K; Bloom, S. R.

    1983-01-01

    Human pancreatic growth hormone releasing factor (GRF (1-44)) is the parent molecule of several peptides recently extracted from pancreatic tumours associated with acromegaly. A study was conducted to examine its effects on the release of growth hormone in normal volunteers and in patients with hypopituitarism and acromegaly. GRF (1-44) dose dependently stimulated the release of growth hormone in normal people and produced no appreciable side effect. This response was grossly impaired in pati...

  12. Efficacy of insect growth regulators as grain protectants against two stored-product pests in wheat and maize.

    Science.gov (United States)

    Kavallieratos, Nickolas G; Athanassiou, Christos G; Vayias, Basileios J; Tomanović, Zeljko

    2012-05-01

    Insect growth regulators (IGRs) (two juvenile hormone analogues [fenoxycarb and pyriproxifen], four chitin synthesis inhibitors [diflubenzuron, flufenoxuron, lufenuron, and triflumuron], one ecdysteroid agonist [methoxyfenozide], and one combination of chitin synthesis inhibitors and juvenile hormone analogues [lufenuron plus fenoxycarb]) were tested in the laboratory against adults of Prostephanus truncatus in maize and against adults of Rhyzopertha dominica in wheat. The tested IGRs were applied in maize at three doses (1, 5, and 10 ppm) and assessed at three temperature levels (20, 25, and 30°C) in the case of P. truncatus, while in the case of R. dominica the above doses were assessed only at 25°C in wheat. In addition to progeny production, mortality of the treated adults after 14 days of exposure in the IGR-treated commodities was assessed. All IGRs were very effective (>88.5% suppression of progeny) against the tested species at doses of $ 5 ppm, while diflubenzuron at 25°C in the case of P. truncatus or lufenuron and pyriproxyfen in the case of R. dominica completely suppressed (100%) progeny production when they were applied at 1 ppm. At all tested doses, the highest values of R. dominica parental mortality were observed in wheat treated with lufenuron plus fenoxycarb. Temperature at the levels examined in the present study did not appear to affect the overall performance in a great extent of the tested IGRs in terms of adult mortality or suppression of progeny production against P. truncatus in treated maize. The tested IGRs may be considered viable grain protectants and therefore as potential components in stored-product integrated pest management. PMID:22564945

  13. Research on the growth orientation of pyrite grains in the colloform textures in Baiyunpu Pb-Zn polymetallic deposit, Hunan, China

    Science.gov (United States)

    Gao, Shang; Huang, Fei; Gu, Xiangping; Chen, Zhenyu; Xing, Miaomiao; Li, Yongli

    2016-08-01

    A large number of colloform-textured pyrites were found in Baiyunpu Pb-Zn ore bodies in Xinshao County, Hunan, China. This study investigates the growth orientation of the pyrite grains in these structures by field emission scanning electron microscopy (FE-SEM), in situ micro X-ray diffraction (μXRD) and electron backscatter diffraction (EBSD). The growth proceeded from micro-crystalline cores in the colloform textures. Moreover, the pyrite layers were discrete and separated by locally significant quantities of galena and calcite. The μXRD results suggested clear crystalline characteristics and weakly preferred orientations of the colloform textures. EBSD confirmed that the pyrite grains exist preferred orientations or in the layered zones. According to the crystal growth theory, the formation and variation of crystal preferred orientations (CPOs) in pyrite are mainly restricted by the internal crystal structure of the pyrite and depends on the external environment conditions, such as trace element concentrations and the supersaturation degree. We inferred the evolutionary regularity of lattice planes with different indices in the pyrite crystal structure from morphological, compositional and growth orientation information, which reflect the crystal growth history of the colloform pyrite. This study will advance our understanding of the growth processes of colloform pyrite and environmental evolution in the Baiyunpu Pb-Zn polymetallic deposits.

  14. Influence of porosity on densification and grain growth kinetics of Ce0.9Gd0.1O1.95 tape

    DEFF Research Database (Denmark)

    Ni, De Wei; Esposito, Vincenzo; Foghmoes, Søren Preben Vagn;

    determined from master viscosity curves, which are comparable to the kinetic values obtained from densification and grain growth. It is indicated that porosity has negligible effect on densification kinetics, but high porosity decreases the chance of particle contact, and grain boundary mobility is therefore...... is accompanied by the change of shape, size and fraction of pores in a given volume. Therefore, porosity can be treated as an extra phase during sintering study. In this work, we presented the densification and grain growth behaviour of Ce0.9Gd0.1O1.95 tape cast layers with different percentage of...... porosity. The emphasis was put on the effect of porosity on densification and grain growth kinetics. Derived from the sintering constitutive laws, the densification and grain growth kinetics were experimentally characterized and analyzed. Furthermore, the activation energies for viscous flow were...

  15. Irradiation induced grain growth and surface emission enhancement of chemically tailored ZnS : Mn/PVOH nanoparticles by Cl+9 ion impact

    International Nuclear Information System (INIS)

    Manganese doped zinc sulfide nanoparticles are fabricated on polyvinyl alcohol dielectric matrix. They are bombarded with energetic chlorine ions (100 MeV). The size of the crystallites is found to increase with ion fluence due to melting led grain growth under ion irradiation. The increased size as a result of grain growth has been observed both in the optical absorption spectra in terms of redshift and in electron microscopic images. The photoluminescence (PL) study was carried out by band to band excitation λex = 220 nm) upon ZnS : Mn, which results into two emission peaks corresponding to surface states and Mn+2 emission, respectively. The ion fluence for irradiation experiment so chosen were 1 x 1011, 5 x 1011, 5 x 1012 and 1013 Cl/cm2. (author)

  16. Irradiation induced grain growth and surface emission enhancement of chemically tailored ZnS : Mn/PVOH nanoparticles by Cl+9 ion impact

    Indian Academy of Sciences (India)

    D Mohanta; S S Nath; N C Mishra; A Choudhury

    2003-04-01

    Manganese doped zinc sulfide nanoparticles are fabricated on polyvinyl alcohol dielectric matrix. They are bombarded with energetic chlorine ions (100 MeV). The size of the crystallites is found to increase with ion fluence due to melting led grain growth under ion irradiation. The increased size as a result of grain growth has been observed both in the optical absorption spectra in terms of redshift and in electron microscopic images. The photoluminescence (PL) study was carried out by band to band excitation ($\\lambda_{ex}$ = 220 nm) upon ZnS : Mn, which results into two emission peaks corresponding to surface states and Mn+2 emission, respectively. The ion fluence for irradiation experiment so chosen were 1 × 1011, 5 × 1011, 5 × 1012 and 1013 Cl/cm2.

  17. Prospecting plant growth promoting bacteria and cyanobacteria as options for enrichment of macro- and micronutrients in grains in rice–wheat cropping sequence

    OpenAIRE

    Anuj Rana; Soumya Ranjan Kabi; Shikha Verma; Anurup Adak; Madan Pal; Yashbir Singh Shivay; Radha Prasanna; Lata Nain

    2015-01-01

    The influence of plant growth promoting bacteria (PGPB) and cyanobacteria, alone and in combination, was investigated on micronutrient enrichment and yield in rice–wheat sequence, over a period of two years. Analysis of variance (ANOVA) in both crops indicated significant differences in soil dehydrogenase activity and micronutrient enrichment in grains (Fe, Zn in rice, and Cu, Mn in wheat). The combined inoculation of Anabaena oscillarioides CR3, Brevundimonas diminuta PR7, and Ochrobactrum a...

  18. Comparison of gene expression profiles and responses to zinc chloride among inter- and intraspecific hybrids with growth abnormalities in wheat and its relatives.

    Science.gov (United States)

    Takamatsu, Kiyofumi; Iehisa, Julio C M; Nishijima, Ryo; Takumi, Shigeo

    2015-07-01

    Hybrid necrosis is a well-known reproductive isolation mechanism in plant species, and an autoimmune response is generally considered to trigger hybrid necrosis through epistatic interaction between disease resistance-related genes in hybrids. In common wheat, the complementary Ne1 and Ne2 genes control hybrid necrosis, defined as type I necrosis. Two other types of hybrid necrosis (type II and type III) have been observed in interspecific hybrids between tetraploid wheat and Aegilops tauschii. Another type of hybrid necrosis, defined here as type IV necrosis, has been reported in F1 hybrids between Triticum urartu and some accessions of Triticum monococcum ssp. aegilopoides. In types I, III and IV, cell death occurs gradually starting in older tissues, whereas type II necrosis symptoms occur only under low temperature. To compare comprehensive gene expression patterns of hybrids showing growth abnormalities, transcriptome analysis of type I and type IV necrosis was performed using a wheat 38k oligo-DNA microarray. Defense-related genes including many WRKY transcription factor genes were dramatically up-regulated in plants showing type I and type IV necrosis, similarly to other known hybrid abnormalities, suggesting an association with an autoimmune response. Reactive oxygen species generation and necrotic cell death were effectively inhibited by ZnCl2 treatment in types I, III and IV necrosis, suggesting a significant association of Ca(2+) influx in upstream signaling of necrotic cell death in wheat hybrid necrosis. PMID:26081164

  19. Microstructure degradation of cermet anodes for solid oxide fuel cells: Quantification of nickel grain growth in dry and in humid atmospheres

    Science.gov (United States)

    Holzer, L.; Iwanschitz, B.; Hocker, Th.; Münch, B.; Prestat, M.; Wiedenmann, D.; Vogt, U.; Holtappels, P.; Sfeir, J.; Mai, A.; Graule, Th.

    The effects of compositional and environmental parameters on the kinetics of microstructural degradation are investigated for porous Ni/CGO anodes in solid oxide fuel cells (SOFC). Improved methodologies of SEM-imaging, segmentation and object recognition are described which enable a precise quantification of nickel grain growth over time. Due to these methodological improvements the grain growth can be described precisely with a standard deviation of only 5-15 nm for each time step. In humid atmosphere (60 vol.% H 2O, 40% N 2/H 2) the growth rates of nickel are very high (up to 140%/100 h) during the initial period (1000 h) the growth rates decrease significantly to nearly 0%/100 h. In contrast, under dry conditions (97 vol.% N 2, 3 vol.% H 2) the growth rates during the initial period are much lower (ca. 1%/100 h) but they do not decrease over a period of 2000 h. In addition to the humidity factor there are other environmental and compositional parameters which have a strong influence on the kinetics of the microstructural degradation. The nickel coarsening is strongly depending on the gas flow rate. Also the initial microstructures and the anode compositions have a big effect on the degradation kinetics. Thereby small average grain sizes, wide distribution of particle size and high contents of nickel lead to higher coarsening and degradation rates. Whereas the nickel coarsening appears to be the dominant degradation mechanism during the initial period (1000 h) in humidified gas. Thereby the evaporation of volatile nickel species may lead to a local increase of the Ni/CGO ratio. Due to the surface wetting of CGO a continuous layer tends to form on the surface of the nickel grains which prevents further grain growth and evaporation of nickel. These phenomena lead to a microstructural reorganization between 1000 and 2300 h of exposure. This complex pattern of degradation phenomena also leads to a change of the amount of active microstructural sites that are

  20. The Effect of Lithium Doping on the Sintering and Grain Growth of SPS-Processed, Non-Stoichiometric Magnesium Aluminate Spinel

    Directory of Open Access Journals (Sweden)

    Yuval Mordekovitz

    2016-06-01

    Full Text Available The effects of lithium doping on the sintering and grain growth of non-stoichiometric nano-sized magnesium aluminate spinel were studied using a spark plasma sintering (SPS apparatus. Li-doped nano-MgO·nAl2O3 spinel (n = 1.06 and 1.21 powders containing 0, 0.20, 0.50 or 1.00 at. % Li were synthesized by the solution combustion method and dense specimens were processed using a SPS apparatus at 1200 °C and under an applied pressure of 150 MPa. The SPS-processed samples showed mutual dependency on the lithium concentration and the alumina-to-magnesia ratio. For example, the density and hardness values of near-stoichiometry samples (n = 1.06 showed an incline up to 0.51 at. % Li, while in the alumina rich samples (n = 1.21, these values remained constant up to 0.53 at. % Li. Studying grain growth revealed that in the Li-MgO·nAl2O3 system, grain growth is limited by Zener pining. The activation energies of undoped, 0.2 and 0.53 at. % Li-MgO·1.21Al2O3 samples were 288 ± 40, 670 ± 45 and 543 ± 40 kJ·mol−1, respectively.

  1. 肺泡生长异常所致婴幼儿肺间质疾病%Alveolar growth abnormalities interstitial lung disease

    Institute of Scientific and Technical Information of China (English)

    邹映雪

    2014-01-01

    虽然间质性肺疾患可见于儿童生长发育的各个时期,但婴幼儿时期有其特殊类型的弥漫性肺间质疾病(diffuse interstitial lung disease,ILD),这种与肺发育直接相关的肺疾患与成人ILD不同.肺泡生长异常(alveolar growth abnormalities,AGA)是常见的导致婴幼儿ILD的原因,本文对此类婴幼儿特殊类型ILD的临床表现、诊断评估、治疗和临床转归进行探讨.

  2. No asthma, no parasites is a rare type of leukemia: chronic myeloid neoplasm with eosinophilia and abnormality of platelet-derived growth factor receptor alpha.

    Science.gov (United States)

    Santiago-Casiano, Mónica; Alemán, Jesse R; Matos-Fernández, Nelson A; Cáceres-Perkins, Wlliam; De La Paz, Maryknoll

    2012-01-01

    Chronic myeloid neoplasm with eosinophilia and abnormality of platelet-derived growth factor receptor alpha (PDGFRA), referred as chronic eosinophilic leukemia, is an extremely rare neoplasm where long-term prognosis is uncertain though a high grade of responsiveness to Imatinib has been reported. The mortality and morbidity associated with chronic eosinophilic leukemia is associated with the degree of tissue involvement, damage, or both at diagnosis. We discuss a case of a young male patient with past medical history of hypoglycemia that presented to the emergency room with a complaints of a sharp abdominal pain localized in the upper quadrants. Laboratories were remarkable for elevated white blood cells with eosinophils predominance, anemia and thrombocytopenia. Bone marrow biopsy dislocated a FIP1L1-PDGFRA fusion gene chronic eosinophilic leukemia. Physicians need to have a high index of suspicion of this rare entity since not all eosinophilias can be interpreted as asthma or parasitis infections. PMID:23156891

  3. The extent of grain yield and plant growth enhancement by plant growth-promoting broad-spectrum Streptomyces sp. in chickpea.

    Science.gov (United States)

    Gopalakrishnan, Subramaniam; Srinivas, Vadlamudi; Alekhya, Gottumukkala; Prakash, Bandikinda; Kudapa, Himabindu; Rathore, Abhishek; Varshney, Rajeev Kumar

    2015-01-01

    The physiological and molecular responses of five strains of Streptomyces sp. (CAI-17, CAI-68, CAI-78, KAI-26 and KAI-27), with their proven potential for charcoal rot disease control in sorghum and plant growth-promotion (PGP) in sorghum and rice, were studied to understand the mechanisms causing the beneficial effects. In this investigation, those five strains were evaluated for their PGP capabilities in chickpea in the 2012-13 and 2013-14 post-rainy seasons. All of the Streptomyces sp. strains exhibited enhanced nodule number, nodule weight, root weight and shoot weight at 30 days after sowing (DAS) and pod number, pod weight, leaf area, leaf weight and stem weight at 60 DAS in both seasons over the un-inoculated control. At crop maturity, the Streptomyces strains had enhanced stover yield, grain yield, total dry matter and seed number plant(-1) in both seasons over the un-inoculated control. In the rhizosphere, the Streptomyces sp. also significantly enhanced microbial biomass carbon, dehydrogenase activity, total nitrogen, available phosphorous and organic carbon in both seasons over the un-inoculated control. Of the five strains of Streptomyces sp., CAI-17, CAI-68 and CAI-78 were superior to KAI-26 and KAI-27 in terms of their effects on root and shoot development, nodule formation and crop productivity. Scanning electron microscopy (SEM) micrographs had revealed the success in colonization of the chickpea roots by all five strains. Quantitative real-time PCR (qRT-PCR) analysis of selected PGP genes of actinomycetes revealed the selective up-regulation of indole-3-acetic acid (IAA)-related and siderophore-related genes by CAI-68 and of β-1,3-glucanase genes by KAI-26. PMID:25646153

  4. Nail abnormalities

    Science.gov (United States)

    ... nails include systemic amyloidosis , malnutrition, vitamin deficiency, and lichen planus . Skin cancers near the nail and fingertip ... the nail bed. Chemotherapy medicines can affect nail growth. Normal aging affects the growth and development of ...

  5. Effects of feeding processed corn stover and distillers grains on growth performance and metabolism of beef cattle.

    Science.gov (United States)

    Chapple, W P; Cecava, M J; Faulkner, D B; Felix, T L

    2015-08-01

    Objectives were to evaluate the effects of replacing corn in feedlot finishing diets with processed corn stover (CS), processed by various combinations of chemical and physical methods, and modified wet distillers grain with solubles (MWDGS) on growth performance, carcass characteristics, digestibility, and ruminal metabolism of cattle. Corn stover was physically processed (ground or extruded) and chemically processed with alkaline agents (CaO and NaOH) to reduce the crystallinity of the lignocellulosic structure. In Exp. 1 steers ( = 18, initial BW = 385 ± 32 kg) and heifers ( = 41, initial BW = 381 ± 27 kg) were allotted to 1 of 5 dietary treatments: 1) 55% dry, cracked corn, 35% MWDGS, 5% vitamin-mineral supplement, and 5% untreated ground CS (), 2) CS treated with 5% CaO (DM basis) and stored in an Ag-Bag (BGCS), 3) CS treated with 5% CaO (DM basis) and extruded (5 EXCS), 4) CS treated with 4% CaO and 1% NaOH (DM basis) and extruded (4,1 EXCS), or 5) CS treated with 3% CaO and 2% NaOH (DM basis) and extruded (3,2 EXCS). Extruded CS was hydrated to 34% moisture, then an additional 16% water was added, as a solution carrying CaO or NaOH or both, via a calibrated pump during processing through a dual-shafted encased extruder (Readco Kurimoto Continuous Processor, York, PA) with the desired exiting temperature of 76.7°C ± 2.8°C. All treated CS diets contained 20% CS and 40% MWDGS (DM basis) to replace 20% corn when compared to CON. There were no effects ( ≥ 0.20) of dietary treatment on ADG, G:F, 12th-rib back fat, marbling score, LM area, or yield grade. However, cattle fed CON had increased ( = 0.02) DMI compared to cattle fed the treated CS diets. In Exp. 2, using the same diets as fed in Exp. 1, ruminally cannulated steers ( = 5; initial BW = 417 ± 21 kg) were fed for 90% of ad libitum intake in a 5 × 5 Latin square design. Apparent digestibility of NDF and ADF increased ( corn with treated CS in feedlot diets containing MWDGS increased fiber

  6. Thermal stability, thermal expansion and grain-growth in exchange-coupled Fe-Pt-Ag-B bulk nanocomposite magnets

    Energy Technology Data Exchange (ETDEWEB)

    Nicula, R., E-mail: radu.nicula@empa.ch [Empa, Swiss Federal Laboratories for Materials Science and Technology, Advanced Materials Processing, Feuerwerkerstr. 39, CH-3602 Thun (Switzerland); Crisan, O.; Crisan, A.D.; Mercioniu, I. [National Institute for Materials Physics, P.O. Box MG-7, 077125 Bucharest-Magurele (Romania); Stir, M. [University of Berne, Department of Chemistry and Biochemistry, Freiestrasse 3, CH-3012 Berne (Switzerland); Vasiliu, F. [National Institute for Materials Physics, P.O. Box MG-7, 077125 Bucharest-Magurele (Romania)

    2015-02-15

    Highlights: • Formation of the L10 FePt hard-magnetic phase (>90%) directly in the as-cast state. • Specific alternating hard/soft nanostructure is stable to 600 °C without grain growth. • Anisotropic and non-linear thermal expansion effects. • The FePtAgB alloy behaves like a single magnetic phase (full exchange coupling). - Abstract: Rare-earth free (RE-free) exchange coupling nanocomposite magnets are intensively studied nowadays due to their potential use in applications demanding stable high-temperature operation and corrosion resistance. In this respect, the FePt alloy system is one of the most actively addressed potential permanent magnet solutions. In FePt alloys, promising magnetic features arise from the co-existence of hard magnetic L1{sub 0} FePt and soft magnetic L1{sub 2} Fe{sub 3}Pt phases emerged from the same metastable precursor. The present work deals with an in-situ temperature-resolved synchrotron radiation study of the thermal stability, thermal expansion and microstructure evolution in exchange-coupled FePtAgB alloys. The as-cast microstructural state as well as the optimized magnetic behavior are given as reference and correlated to the observed microstructural evolution with temperature. The melt-spun Fe{sub 48}Pt{sub 28}Ag{sub 6}B{sub 18} alloy ribbons were examined in situ by synchrotron X-ray powder diffraction from ambient temperature up to 600 °C. The FePt-Fe{sub 3}Pt exchange-coupled microstructure achieved by rapid solidification is not significantly altered during the high temperature exposure. The thermal expansion of the FePt L1{sub 0} unit cell has been found to be strongly anisotropic, being essentially an in-plane expansion which may be seen as an anisotropic invar effect. For the FePt L1{sub 0} phase, a significant deviation from linear thermal expansion is observed at the Curie temperature T{sub C} = 477 °C. This non-linear behavior above T{sub C} is tentatively linked to a diffusion/segregation mechanism of Ag

  7. Effects of feeding processed corn stover and distillers grains on growth performance and metabolism of beef cattle.

    Science.gov (United States)

    Chapple, W P; Cecava, M J; Faulkner, D B; Felix, T L

    2015-08-01

    Objectives were to evaluate the effects of replacing corn in feedlot finishing diets with processed corn stover (CS), processed by various combinations of chemical and physical methods, and modified wet distillers grain with solubles (MWDGS) on growth performance, carcass characteristics, digestibility, and ruminal metabolism of cattle. Corn stover was physically processed (ground or extruded) and chemically processed with alkaline agents (CaO and NaOH) to reduce the crystallinity of the lignocellulosic structure. In Exp. 1 steers ( = 18, initial BW = 385 ± 32 kg) and heifers ( = 41, initial BW = 381 ± 27 kg) were allotted to 1 of 5 dietary treatments: 1) 55% dry, cracked corn, 35% MWDGS, 5% vitamin-mineral supplement, and 5% untreated ground CS (), 2) CS treated with 5% CaO (DM basis) and stored in an Ag-Bag (BGCS), 3) CS treated with 5% CaO (DM basis) and extruded (5 EXCS), 4) CS treated with 4% CaO and 1% NaOH (DM basis) and extruded (4,1 EXCS), or 5) CS treated with 3% CaO and 2% NaOH (DM basis) and extruded (3,2 EXCS). Extruded CS was hydrated to 34% moisture, then an additional 16% water was added, as a solution carrying CaO or NaOH or both, via a calibrated pump during processing through a dual-shafted encased extruder (Readco Kurimoto Continuous Processor, York, PA) with the desired exiting temperature of 76.7°C ± 2.8°C. All treated CS diets contained 20% CS and 40% MWDGS (DM basis) to replace 20% corn when compared to CON. There were no effects ( ≥ 0.20) of dietary treatment on ADG, G:F, 12th-rib back fat, marbling score, LM area, or yield grade. However, cattle fed CON had increased ( = 0.02) DMI compared to cattle fed the treated CS diets. In Exp. 2, using the same diets as fed in Exp. 1, ruminally cannulated steers ( = 5; initial BW = 417 ± 21 kg) were fed for 90% of ad libitum intake in a 5 × 5 Latin square design. Apparent digestibility of NDF and ADF increased ( diets compared with CON, regardless of the treatment applied. Ruminal pH was

  8. Strategies to suppress grain growth of nanocrystalline aluminum%纳米铝晶粒生长的抑制方法

    Institute of Scientific and Technical Information of China (English)

    Gowoon JEONG; Jooyoung PARK; Singon KANG; Hyunjoo CHOI

    2014-01-01

    对纳米铝、铝合金和铝基化合物的晶粒生长行为进行了比较。首先,采用球磨粉末的烧结方法制备纳米铝。然后,添加能在晶界形成热稳定二次相和阻碍晶界运动的元素,如Mn、Zr和混合稀土元素,形成纳米铝合金。最后,因为多壁碳纳米管有望在晶界处抑制晶粒生长,因此,制备含有多壁碳纳米管的纳米铝复合材料。将3种样品在550ºC,5 d下进行退火处理,比较了退火时间对样品维氏硬度的影响。结果表明,采用多壁碳纳米管阻碍纳米铝晶粒生长的方法最为有效。%The grain growth behaviors of nanocrystalline aluminum, alloy and composite are compared. First, nanocrystalline aluminum is fabricated by consolidation of ball-milled powder. Second, nanocrystalline aluminum alloy is designed to have elements such as Mn, Zr, and Misch metals, which can form thermally stable second phases at grain boundaries and also drag the movement of grain boundaries. Third, nanocrystalline aluminum-based composites containing multi-walled carbon nanotubes (MWCNTs) are also prepared because MWCNTs are expected to be located at grain boundaries and to suppress the grain growth of nanocrystalline aluminum. These three types of samples are annealed at 550 °C for up to 5 d and the effect of annealing time on Vickers hardness of the samples is compared. As a result, MWCNTs are found to be most effective to impede grain growth of nanocrystalline aluminum.

  9. Abnormal expression of vascular endothelial growth factor (VEGF) and its clinical features in tissues of human lung cancer

    Institute of Scientific and Technical Information of China (English)

    Xinhua Wu; Dengfu Yao; Gongshen Shi; Liwei Qiu; Wei Wu; Songshi Ni; Xueguang Zhang

    2005-01-01

    Objective: Angiogennesis, the formation of new blood vessels from the existing vascular bed, is essential step for growth and invasion of primary tumor. Vascular endothelial growth-factor (VEGF) is known to play crucial role in tumor angiogenesis. In the present study, we investigate the expression of VEGF and VEGF-mRNA in the angiogennesis, metastasis and prognosis of lung cancer.Methods: The VEGF cellular distributions and expression in 38 specimens of patients with lung cancer were investigated with immunohistochemistry stain technology. The total RNAs in 38 tissues of lung cancer was measured, then the levels of VEGF-mRNA expression were analyzed by a reverse-transcription polymerase chain reaction (RT-PCR) assay. The levels of VEGF in sera of patients with lung cancer, benign lung diseases and healthy controls were detected through Enzyme linked immunosorbent assay (ELISA) method. Results: The VEGF positive stain was 76% in 38 cases of lung cancer specimens. The 89% rate of VEGF stain was found for clinical stage Ⅲ cases and 92%for stage Ⅳ lung cancers. The significantly higher expression of VEGF was evidenced in patients with lymph node metastasis (84 % ), distant metastasis (90%), and lung cancers with lower histological differentiation (89%), respectively. The expression level of total RNA was significantly higher in patients with lung cancers than that in their paracancerous or distant lung tissues. The VEGF expressions were tightly correlated with total RNA concentration of lung carcinoma ( P < 0.01 ). The predominant expressions of VEGF121 and VEGF165 gene fragments were found in lung cancer specimens by RT-PCR analysis. No significant difference of serum VEGF levels was detected between cases with lung cancer and patients with benign diseases. However, the VEGF level of cases with benign diseases was decreased significantly after patients with anti-inflammation medication. Conclusion: The present data suggested that the tumor tissue VEGF

  10. A splice site mutation in laminin-α2 results in a severe muscular dystrophy and growth abnormalities in zebrafish.

    Directory of Open Access Journals (Sweden)

    Vandana A Gupta

    Full Text Available Congenital muscular dystrophy (CMD is a clinically and genetically heterogeneous group of inherited muscle disorders. In patients, muscle weakness is usually present at or shortly after birth and is progressive in nature. Merosin deficient congenital muscular dystrophy (MDC1A is a form of CMD caused by a defect in the laminin-α2 gene (LAMA2. Laminin-α2 is an extracellular matrix protein that interacts with the dystrophin-dystroglycan (DGC complex in membranes providing stability to muscle fibers. In an N-ethyl-N-nitrosourea mutagenesis screen to develop zebrafish models of neuromuscular diseases, we identified a mutant fish that exhibits severe muscular dystrophy early in development. Genetic mapping identified a splice site mutation in the lama2 gene. This splice site is highly conserved in humans and this mutation results in mis-splicing of RNA and a loss of protein function. Homozygous lama2 mutant zebrafish, designated lama2(cl501/cl501, exhibited reduced motor function and progressive degeneration of skeletal muscles and died at 8-15 days post fertilization. The skeletal muscles exhibited damaged myosepta and detachment of myofibers in the affected fish. Laminin-α2 deficiency also resulted in growth defects in the brain and eye of the mutant fish. This laminin-α2 deficient mutant fish represents a novel disease model to develop therapies for modulating splicing defects in congenital muscular dystrophies and to restore the muscle function in human patients with CMD.

  11. Significance of abnormal serum binding of insulin-like growth factor II in the development of hypoglycemia in patients with non-islet-cell tumors

    International Nuclear Information System (INIS)

    The authors reported that serum and tumor from a hypoglycemic patient with a fibrosarcoma contained insulin-like growth factor II (IGF-II), mostly in a large molecular form designated big IGF-II. They now describe two additional patients with non-islet-cell tumor with hypoglycemia (NICTH) whose sera contained big IGF-II. Removal of the tumor eliminated most of the big IGF-II from the sera of two patients. Because specific IGF-binding proteins modify the bioactivity of IGFs, the sizes of the endogenous IGF-binding protein complexes were determined after neutral gel filtration through Sephadex G-200. Normally about 75% of IGFs are carried as a ternary complex of 150 kDa consisting of IGF, a growth hormone (GH)-dependent IGF-binding protein, and an acid-labile complexing component. The three patients with NICTH completely lacked the 150-kDa complex. IGF-II was present as a 60-kDa complex with variable contributions of smaller complexes. In the immediate postoperative period, a 110-kDa complex appeared rather than the expected 150-kDa complex. Abnormal IGF-II binding may be important in NICTH because the 150-kDa complexes cross the capillary membrane poorly. The smaller complexes present in our patients' sera would be expected to enter interstitial fluid readily, and a 4- to 5-fold increase in the fraction of IGFs reaching the target cells would result

  12. Significance of abnormal serum binding of insulin-like growth factor II in the development of hypoglycemia in patients with non-islet-cell tumors

    Energy Technology Data Exchange (ETDEWEB)

    Daughaday, W.H.; Kapadia, M. (Washington Univ. School of Medicine, St. Louis, MO (USA))

    1989-09-01

    The authors reported that serum and tumor from a hypoglycemic patient with a fibrosarcoma contained insulin-like growth factor II (IGF-II), mostly in a large molecular form designated big IGF-II. They now describe two additional patients with non-islet-cell tumor with hypoglycemia (NICTH) whose sera contained big IGF-II. Removal of the tumor eliminated most of the big IGF-II from the sera of two patients. Because specific IGF-binding proteins modify the bioactivity of IGFs, the sizes of the endogenous IGF-binding protein complexes were determined after neutral gel filtration through Sephadex G-200. Normally about 75% of IGFs are carried as a ternary complex of 150 kDa consisting of IGF, a growth hormone (GH)-dependent IGF-binding protein, and an acid-labile complexing component. The three patients with NICTH completely lacked the 150-kDa complex. IGF-II was present as a 60-kDa complex with variable contributions of smaller complexes. In the immediate postoperative period, a 110-kDa complex appeared rather than the expected 150-kDa complex. Abnormal IGF-II binding may be important in NICTH because the 150-kDa complexes cross the capillary membrane poorly. The smaller complexes present in our patients' sera would be expected to enter interstitial fluid readily, and a 4- to 5-fold increase in the fraction of IGFs reaching the target cells would result.

  13. Mechanism of the formation of peripheral coarse grain structure in hot extrusion of Al-4.5Zn-1Mg

    Science.gov (United States)

    Eivani, A. R.; Zhou, J.; Duszczyk, J.

    2016-04-01

    Microstructural evolution leading to peripheral coarse grain (PCG) structure in hot extruded Al-4.5Zn-1Mg rods is investigated. The extent of dynamic recrystallization (DRX) in the as-extruded product falls not in line with the basis over which the existing mechanisms for interpretation of PCG formation are built. A new mechanism is therefore proposed based on partial DRX during extrusion and nucleation and abnormal growth of statically recrsystallised grains.

  14. Cerebellar microfolia and other abnormalities of neuronal growth, migration, and lamination in the Pit1dw-J homozygote mutant mouse

    Science.gov (United States)

    Sekiguchi, M.; Abe, H.; Moriya, M.; Tanaka, O.; Nowakowski, R. S.

    1998-01-01

    The Snell dwarf mouse (Pit1dw-J homozygote) has a mutation in the Pit1 gene that prevents the normal formation of the anterior pituitary. In neonates and adults there is almost complete absence of growth hormone (GH), prolactin (PRL), thyroxin (T4), and thyroid-stimulating hormone (TSH). Since these hormones have been suggested to play a role in normal development of the central nervous system (CNS), we have investigated the effects of the Pit1dw-J mutation on the cerebellum and hippocampal formation. In the cerebellum, there were abnormalities of both foliation and lamination. The major foliation anomalies were 1) changes in the relative size of specific folia and also the proportional sizes of the anterior vs posterior cerebellum; and 2) the presence of between one and three microfolia per half cerebellum. The microfolia were all in the medial portion of the hemisphere in the caudal part of the cerebellum. Each microfolium was just rostral to a normal fissure and interposed between the fissure and a normal gyrus. Lamination abnormalities included an increase in the number of single ectopic granule cells in the molecular layer in both cerebellar vermis (86%) and hemisphere (40%) in comparison with the wild-type mouse. In the hippocampus of the Pit1dw-J homozygote mouse, the number of pyramidal cells was decreased, although the width of the pyramidal cell layer throughout areas CA1-CA3 appeared to be normal, but less densely populated than in the wild-type mouse. Moreover, the number of granule cells that form the granule cell layer was decreased from the wild-type mouse and some ectopic granule cells (occurring both as single cells and as small clusters) were observed in the innermost portion of the molecular layer. The abnormalities observed in the Pit1dw-J homozygote mouse seem to be caused by both direct and indirect effects of the deficiency of TSH (or T4), PRL, or GH rather than by a direct effect of the deletion of Pit1.

  15. Improved plant growth and Zn accumulation in grains of rice (Oryza sativa L.) by inoculation of endophytic microbes isolated from a Zn Hyperaccumulator, Sedum alfredii H.

    Science.gov (United States)

    Wang, Yuyan; Yang, Xiaoe; Zhang, Xincheng; Dong, Lanxue; Zhang, Jie; Wei, Yanyan; Feng, Ying; Lu, Lingli

    2014-02-26

    This study is to investigate the possibility of zinc (Zn) biofortification in the grains of rice (Oryza sativa L.) by inoculation of endophytic strains isolated from a Zn hyperaccumulator, Sedum alfredii Hance. Five endophytic strains, Burkholderia sp. SaZR4, Burkholderia sp. SaMR10, Sphingomonas sp. SaMR12, Variovorax sp. SaNR1, and Enterobacter sp. SaCS20, isolated from S. alfredii, were inoculated in the roots of Japonica rice Nipponbare under hydroponic condition. Fluorescence images showed that endophytic strains successfully colonized rice roots after 72 h. Improved root morphology and plant growth of rice was observed after inoculation with endophytic strains especially SaMR12 and SaCS20. Under hydroponic conditions, endophytic inoculation with SaMR12 and SaCS20 increased Zn concentration by 44.4% and 51.1% in shoots, and by 73.6% and 83.4% in roots, respectively. Under soil conditions, endophytic inoculation with SaMR12 and SaCS20 resulted in an increase of grain yields and elevated Zn concentrations by 20.3% and 21.9% in brown rice and by 13.7% and 11.2% in polished rice, respectively. After inoculation of SaMR12 and SaCS20, rhizosphere soils of rice plants contained higher concentration of DTPA-Zn by 10.4% and 20.6%, respectively. In situ micro-X-ray fluorescence mapping of Zn confirmed the elevated Zn content in the rhizosphere zone of rice treated with SaMR12 as compared with the control. The above results suggested that endophytic microbes isolated from S. alfredii could successfully colonize rice roots, resulting in improved root morphology and plant growth, increased Zn bioavailability in rhizosphere soils, and elevated grain yields and Zn densities in grains. PMID:24447030

  16. Combining x-ray diffraction contrast tomography and mesoscale grain growth simulations in strontium titanate: An integrated approach for the investigation of microstructure evolution

    DEFF Research Database (Denmark)

    Syha, Melanie; Baürer, Michael; Rheinheimer, Wolfgang;

    2013-01-01

    Motivated by the recently reported a growth anomaly in strontium titatate bulk samples1, the microstructure of bulk strontium titanate has been investigated by an integrated approach comprising conventional metallography, three dimensional X-ray diffraction contrast tomography (DCT)2, and the obs......Motivated by the recently reported a growth anomaly in strontium titatate bulk samples1, the microstructure of bulk strontium titanate has been investigated by an integrated approach comprising conventional metallography, three dimensional X-ray diffraction contrast tomography (DCT)2......, and the observation of pore shapes in combination with mesoscale grain growth simulations. The microstructural evolution in strontium titanate has been characterized alternating ex-situ annealing and high energy X-ray DCT measurements, resulting in three dimensional microstructure reconstructions which...

  17. Fenton process-affected transformation of roxarsone in paddy rice soils: Effects on plant growth and arsenic accumulation in rice grain.

    Science.gov (United States)

    Qin, Junhao; Li, Huashou; Lin, Chuxia

    2016-08-01

    Batch and greenhouse experiments were conducted to examine the effects of Fenton process on transformation of roxarsone in soils and its resulting impacts on the growth of and As uptake by a rice plant cultivar. The results show that addition of Fenton reagent markedly accelerated the degradation of roxarsone and produced arsenite, which was otherwise absent in the soil without added Fenton reagent. Methylation of arsenate was also enhanced by Fenton process in the earlier part of the experiment due to abundant supply of arsenate from Roxarsone degradation. Overall, addition of Fenton reagent resulted in the predominant presence of arsenate in the soils. Fenton process significantly improved the growth of rice in the maturity stage of the first crop, The concentration of methylated As species in the rice plant tissues among the different growth stages was highly variable. Addition of Fenton reagent into the soils led to reduced uptake of soil-borne As by the rice plants and this had a significant effect on reducing the accumulation of As in rice grains. The findings have implications for understanding As biogeochemistry in paddy rice field receiving rainwater-borne H2O2 and for development of mitigation strategies to reduce accumulation of As in rice grains.

  18. A novel way of modifying nano grain size by solution concentration in the growth of ZnAl2O4 thin films

    International Nuclear Information System (INIS)

    A novel route to the growth of thin films of ZnAl2O4 in nano-scale order was developed and nano-thin films of ZnAl2O4 are grown. The variation of grain size with solution concentration is reported. The thin film was deposited by modified liquid-phase deposition (LPD) technique using a novel acid based chemical reaction for the first time to ternary system. This modified LPD is based on a novel reaction that favours the formation of nanostructures during the treatment of a precursor (here ZnO) and a metal foil (Al) in diluted HF acid. The acid serves both as a solvent and catalyst. Usually, in wet process synthesis of binary systems, the metal foil will act as F- ion scavenger. In this method, formation of a ternary compound as well as growth of thin film nanostructures of that compound was achieved by the same chemical reaction at room temperature. The role of acid concentration in the nanostructure formation is discussed. The relationship between HF concentration and grain size were also graphically enumerated. Structural, compositional and surface morphological properties of thin films were studied using Philips, Xpert-MPD: X-ray diffractometer and Philips, ESEM-TMP + EDAX, Nanoscope-III: AFM. The technique is a novel, simple and low cost route for the growth of nano-thin films of ternary oxide material

  19. Formation of Graphene Grain Boundaries on Cu(100) Surface and a Route Towards Their Elimination in Chemical Vapor Deposition Growth

    OpenAIRE

    Qinghong Yuan; Guangyao Song; Deyan Sun; Feng Ding

    2014-01-01

    Grain boundaries (GBs) in graphene prepared by chemical vapor deposition (CVD) greatly degrade the electrical and mechanical properties of graphene and thus hinder the applications of graphene in electronic devices. The seamless stitching of graphene flakes can avoid GBs, wherein the identical orientation of graphene domain is required. In this letter, the graphene orientation on one of the most used catalyst surface — Cu(100) surface, is explored by density functional theory (DFT) calculatio...

  20. Effect of Mg Addition on Inhibiting Austenite Grain Growth in Heat Affected Zones of Ti-Bearing Low Carbon Steels%Effect of Mg Addition on Inhibiting Austenite Grain Growth in Heat Affected Zones of Ti-Bearing Low Carbon Steels

    Institute of Scientific and Technical Information of China (English)

    ZHU Kai; YANG Jian; WANG Rui-zhi; YANG Zhen-guo

    2011-01-01

    To study the effect of Mg addition on inhibiting weld heat affected zones (HAZ) austenite grain growth of Ti-bearing low carbon steels, two steels with and without Mg treated were prepared using a laboratory vacuum. The welding testing was simulated by Gleeble 3500 thermomechanical simulator. The performance of HAZ was investiga ted that the toughness was improved from 3.3 to 185 J by adding 0. 005%Mg (in mass percent) to the steel, and the fracture mechanism changed from cleavage fracture to toughness fracture. Through in-situ observation by a confocal scanning laser microscope, a significant result was found that the austenite grain of the steel with Mg treated was still keeping fine-grained structure after holding at 1 400℃ and lasting for 300 s. This inhibition of austenite grain growth was mainly attributed to the formation of pinning particles after the addition of Mg. The obtained results pro pose a potential method for improving HAZ toughness of structure steels.

  1. Section 1: Interfacial reactions and grain growth in ferroelectric SrBi{sub 2}Ta{sub 2}O (SBT) thin films on Si substrates

    Energy Technology Data Exchange (ETDEWEB)

    Dickerson, B.D.; Zhang, X.; Desu, S.B. [Virginia Polytechnic Institute and State Univ., Blacksburg, VA (United States)] [and others

    1997-04-01

    Much of the cost of traditional infrared cameras based on narrow-bandgap photoelectric semiconductors comes from the cryogenic cooling systems required to achieve high detectivity. Detectivity is inversely proportional to noise. Generation-recombination noise in photoelectric detectors increases roughly exponentially with temperature, but thermal noise in photoelectric detectors increases only linearly with temperature. Therefore `thermal detectors perform far better at room temperature than 8-14 {mu}m photon detectors.` Although potentially more affordable, uncooled pyroelectric cameras are less sensitive than cryogenic photoelectric cameras. One way to improve the sensitivity to cost ratio is to deposit ferroelectric pixels with good electrical properties directly on mass-produced, image-processing chips. `Good` properties include a strong temperature dependence of the remanent polarization, P{sub r}, or the relative dielectric constant, {epsilon}{sub r}, for sensitive operation in pyroelectric or dielectric mode, respectively, below or above the Curie temperature, which is 320 C for SBT. When incident infrared radiation is chopped, small oscillations in pixel temperature produce pyroelectric or dielectric alternating currents. The sensitivity of ferroelectric thermal detectors depends strongly on pixel microstructure, since P{sub r} and {epsilon}{sub r} increase with grain size during annealing. To manufacture SBT pixels on Si chips, acceptable SBT grain growth must be achieved at the lowest possible oxygen annealing temperature, to avoid damaging the Si chip below. Therefore current technical progress describes how grain size, reaction layer thickness, and electrical properties develop during the annealing of SBT pixels deposited on Si.

  2. Prospecting plant growth promoting bacteria and cyanobacteria as options for enrichment of macro- and micronutrients in grains in rice–wheat cropping sequence

    Directory of Open Access Journals (Sweden)

    Anuj Rana

    2015-12-01

    Full Text Available The influence of plant growth promoting bacteria (PGPB and cyanobacteria, alone and in combination, was investigated on micronutrient enrichment and yield in rice–wheat sequence, over a period of two years. Analysis of variance (ANOVA in both crops indicated significant differences in soil dehydrogenase activity and micronutrient enrichment in grains (Fe, Zn in rice, and Cu, Mn in wheat. The combined inoculation of Anabaena oscillarioides CR3, Brevundimonas diminuta PR7, and Ochrobactrum anthropi PR10 (T6 significantly increased nitrogen, phosphorus, and potassium (NPK content and improved rice yield by 21.2%, as compared to the application of recommended dose of NPK fertilizers (T2. The treatment T5 (Providencia sp. PR3 + B. diminuta PR7 + O. anthropi PR10 recorded an enhancement of 13–16% in Fe, Zn, Cu, and Mn concentrations, respectively, in rice grains. In wheat, Providencia sp. PW5 (T6 recorded the highest yield (5.23 Mg ha−1 and significantly higher enrichment of Fe and Cu (44–45% in the grains. This study highlighted the promise of combinations of cyanobacteria/bacteria and their synergistic action in biofortification and providing savings of 40–60 kg N ha−1. Future focus needs to be towards integrating such promising environment-friendly and environmentally sustainable options in nutrient management strategies for this cropping sequence.

  3. Increased Lung Expression of Anti-Angiogenic Factors in Down Syndrome: Potential Role in Abnormal Lung Vascular Growth and the Risk for Pulmonary Hypertension

    Science.gov (United States)

    Galambos, Csaba; Minic, Angela D.; Bush, Douglas; Nguyen, Dominique; Dodson, Blair; Seedorf, Gregory; Abman, Steven H.

    2016-01-01

    Background and Aims Infants with Down syndrome (DS) or Trisomy 21, are at high risk for developing pulmonary arterial hypertension (PAH), but mechanisms that increase susceptibility are poorly understood. Laboratory studies have shown that early disruption of angiogenesis during development impairs vascular and alveolar growth and causes PAH. Human chromosome 21 encodes known anti-angiogenic factors, including collagen18a1 (endostatin, ES), ß-amyloid peptide (BAP) and Down Syndrome Critical Region 1 (DSCR-1). Therefore, we hypothesized that fetal lungs from subjects with DS are characterized by early over-expression of anti-angiogenic factors and have abnormal lung vascular growth in utero. Methods Human fetal lung tissue from DS and non-DS subjects were obtained from a biorepository. Quantitative reverse transcriptase PCR (qRT-PCR) was performed to assay 84 angiogenesis-associated genes and individual qRT-PCR was performed for ES, amyloid protein precursor (APP) and DSCR1. Western blot analysis (WBA) was used to assay lung ES, APP and DSCR-1 protein contents. Lung vessel density and wall thickness were determined by morphometric analysis. Results The angiogenesis array identified up-regulation of three anti-angiogenic genes: COL18A1 (ES), COL4A3 (tumstatin) and TIMP3 (tissue inhibitor of metallopeptidase 3) in DS lungs. Single qRT-PCR and WBA showed striking elevations of ES and APP mRNA (p = 0.022 and p = 0.001) and protein (p = 0.040 and p = 0.002; respectively). Vessel density was reduced (p = 0.041) and vessel wall thickness was increased in DS lung tissue (p = 0.033) when compared to non-DS subjects. Conclusions We conclude that lung anti-angiogenic factors, including COL18A1 (ES), COL4A3, TIMP3 and APP are over-expressed and fetal lung vessel growth is decreased in subjects with DS. We speculate that increased fetal lung anti-angiogenic factor expression due to trisomy 21 impairs lung vascular growth and signaling, which impairs alveolarization and

  4. In-situ observations on interphase boundary migration and grain growth during α/γ phase transformation in iron-4. 2%Cr alloy%Fe-4.2%Cr合金α/γ相变中相边界移动和晶粒长大的原位观察

    Institute of Scientific and Technical Information of China (English)

    渡边忠雄

    2005-01-01

    In-situ observations on α/γ phase transformation were made to study the effects of grain boundary microstructures on the formation of a new phase and the migration of α/γ interphase boundary in an iron-4. 2%Cr alloy. It was found that triple junctions with more random boundaries could be the primary nucleation sites for a new phase, while triple junctions with low angle or low ∑ coincidence boundaries did not play any role as preferential sites. The migration of α/γ interphase boundary during heating over the transformation temperature range showed the two stage behaviour characterized by a stage with a migration velocity of 0. 33~0. 75 mm/s and secondly by a stage with 3. 7~7. 6 mm/s. It was also found that abnormal grain growth and a high density of ∑3 coincidence boundaries could occur in a phase with bcc structure after cycling of α/γ phase transformation. A new mechanism of nucleation and growth of a new phase in α/γ phase transformation is proposed on the basis of roles of plane-matching interphase boundaries, as previously discussed on the origin of anisotropy of grain growth due to the migration of {110} plane-matching boundaries in Fe-3%Si alloy. The most recent theoretical work on the distribution of plane-matching boundaries in solids with different crystal structures was found to be useful for the understanding of nucleation and growth during α/γ phase transformation.

  5. Environmental factors and interactions with mycobiota of grain and grapes: effects on growth, deoxynivalenol and ochratoxin production by Fusarium culmorum and Aspergillus carbonarius.

    Science.gov (United States)

    Magan, Naresh; Aldred, David; Hope, Russell; Mitchell, David

    2010-03-01

    Mycotoxigenic fungi colonizing food matrices are inevitably competing with a wide range of other resident fungi. The outcomes of these interactions are influenced by the prevailing environmental conditions and the competing species. We have evaluated the competitiveness of F. culmorum and A. carbonarius in the grain and grape food chain for their in vitro and in situ dominance in the presence of other fungi, and the effect that such interactions have on colony interactions, growth and deoxynivalenol (DON) and ochratoxin A (OTA) production. The Index of Dominance shows that changes in water activity (a(w)) and temperature affect the competitiveness of F. culmorum and A. carbonarius against up to nine different fungi. Growth of both mycotoxigenic species was sometimes inhibited by the presence of other competing fungi. For example, A. niger uniseriate and biseriate species decreased growth of A. carbonarius, while Aureobasidium pullulans and Cladosporium species stimulated growth. Similar changes were observed when F. graminearum was interacting with other grain fungi such as Alternaria alternata, Cladopsorium herbarum and Epicoccum nigrum. The impact on DON and OTA production was very different. For F. culmorum, the presence of other species often inhibited DON production over a range of environmental conditions. For A. carbonarius, on a grape-based medium, the presence of certain species resulted in a significant stimulation of OTA production. However, this was influenced by both temperature and a(w) level. This suggests that the final mycotoxin concentrations observed in food matrices may be due to complex interactions between species and the environmental history of the samples analyzed. PMID:22069589

  6. Grain charging in protoplanetary discs

    OpenAIRE

    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 a...

  7. Nanocrystal grain growth and device architectures for high-efficiency CdTe ink-based photovoltaics.

    Science.gov (United States)

    Crisp, Ryan W; Panthani, Matthew G; Rance, William L; Duenow, Joel N; Parilla, Philip A; Callahan, Rebecca; Dabney, Matthew S; Berry, Joseph J; Talapin, Dmitri V; Luther, Joseph M

    2014-09-23

    We study the use of cadmium telluride (CdTe) nanocrystal colloids as a solution-processable "ink" for large-grain CdTe absorber layers in solar cells. The resulting grain structure and solar cell performance depend on the initial nanocrystal size, shape, and crystal structure. We find that inks of predominantly wurtzite tetrapod-shaped nanocrystals with arms ∼5.6 nm in diameter exhibit better device performance compared to inks composed of smaller tetrapods, irregular faceted nanocrystals, or spherical zincblende nanocrystals despite the fact that the final sintered film has a zincblende crystal structure. Five different working device architectures were investigated. The indium tin oxide (ITO)/CdTe/zinc oxide structure leads to our best performing device architecture (with efficiency >11%) compared to others including two structures with a cadmium sulfide (CdS) n-type layer typically used in high efficiency sublimation-grown CdTe solar cells. Moreover, devices without CdS have improved response at short wavelengths.

  8. Nanocrystal grain growth and device architectures for high-efficiency CdTe ink-based photovoltaics.

    Science.gov (United States)

    Crisp, Ryan W; Panthani, Matthew G; Rance, William L; Duenow, Joel N; Parilla, Philip A; Callahan, Rebecca; Dabney, Matthew S; Berry, Joseph J; Talapin, Dmitri V; Luther, Joseph M

    2014-09-23

    We study the use of cadmium telluride (CdTe) nanocrystal colloids as a solution-processable "ink" for large-grain CdTe absorber layers in solar cells. The resulting grain structure and solar cell performance depend on the initial nanocrystal size, shape, and crystal structure. We find that inks of predominantly wurtzite tetrapod-shaped nanocrystals with arms ∼5.6 nm in diameter exhibit better device performance compared to inks composed of smaller tetrapods, irregular faceted nanocrystals, or spherical zincblende nanocrystals despite the fact that the final sintered film has a zincblende crystal structure. Five different working device architectures were investigated. The indium tin oxide (ITO)/CdTe/zinc oxide structure leads to our best performing device architecture (with efficiency >11%) compared to others including two structures with a cadmium sulfide (CdS) n-type layer typically used in high efficiency sublimation-grown CdTe solar cells. Moreover, devices without CdS have improved response at short wavelengths. PMID:25133302

  9. Inhibitory effect of cinnamon, clove, lemongrass, oregano and palmarose essential oils on growth and fumonisin B1 production by Fusarium proliferatum in maize grain.

    Science.gov (United States)

    Velluti, A; Sanchis, V; Ramos, A J; Egido, J; Marín, S

    2003-12-31

    The effect of cinnamon, clove, oregano, palmarose and lemongrass oils on growth and FB1 production by three different isolates of F. proliferatum in irradiated maize grain at 0.995 and 0.950 aw and at 20 and 30 degrees C was evaluated. The five essential oils inhibited growth of F. proliferatum isolates at 0.995 aw at both temperatures, while at 0.950 aw only cinnamon, clove and oregano oils were effective in inhibiting growth of F. proliferatum at 20 degrees C and none of them at 30 degrees C. Cinnamon, oregano and palmarose oils had significant inhibitory effect on FB1 production by the three strains of F. proliferatum at 0.995 aw and both temperatures, while clove and lemongrass oils had only significant inhibitory effect at 30 degrees C. No differences were found using 500 or 1000 microg essential oil g(-1). At 0.950 aw, none of the essential oils had any significant effect on FB1 production. The results suggest that mainly cinnamon and oregano oils could be effective in controlling growth and FB1 production by F. proliferatum in maize under preharvest conditions. PMID:14623380

  10. 激光熔注中增强相颗粒对晶粒生长影响的CA模拟∗%Simulation of effect of reinforcement particles on grain growth during laser melt inj ection based on CA

    Institute of Scientific and Technical Information of China (English)

    赵明娟; 邓志成; 赵龙志

    2015-01-01

    基于元胞自动机法,结合 Moore 型邻居定义和晶粒生长理论,建立了增强相颗粒 SiC 对镁合金激光熔注中表层316L不锈钢晶粒生长的影响模型,模型考虑了晶界迁移率和晶界能等因素,实现了不同增强相颗粒体积分数和颗粒尺寸对晶粒生长影响的计算机模拟.结果表明,所建立的模型能较好的模拟晶粒生长过程,所得晶粒生长指数为0.42;增强相颗粒体积分数含量越高,晶粒生长越慢,晶粒尺寸越小;增强相颗粒尺寸越小,晶粒生长的越慢,晶粒尺寸越小,组织越均匀.%Based on the cellular automaton method,the definition of Moore neighbor type and the grain growth theory,a model of simulation for the grain growth process was established,which simulated the influence of the SiC reinforcement particles and 316L stainless steel reinforced the surface of magnesium alloy by laser melt inj ection.Many factors such as grain boundary mobility and grain boundary energy were considered in the mod-el.Simulated the influence of different volume fraction and size of reinforcement particles on the grain growth process were obtained.The results show that:the grain growth process can be simulated very well by the meth-od,the grain growth index can be obtained as 0.42;the higher volume fraction of the particles,the slower the speed of the grain growth,the smaller grain size;the smaller the particles size is,the slower the grain grows, the smaller grain size and the microstructure is more uniform.

  11. Effect of presowing gamma irradiation of seeds on the growth, development and yield of maize grain and green mass

    International Nuclear Information System (INIS)

    The experiment was carried out during the 1982-1983 period with maize hybrids Px-20, Kn-611 and H-708 irradiated with 500, 1000, 1500, 2000 and 3000 R. Gamma irradiation of the seeds had no unidirectional effect on the germinative power, laboratory and field germinating ability, volume of the root system (up to day 20 after germination), height of plants and cobbing, structural elements of the cobs and plants. Presowing seed germination with the three hybrids did not increase the grain yield neither that of the green mass and the dry matter. Under 500 R irradiation of the H-708 hybrid a reliable difference in the green mass yield was obtained only in 1982. 2 tabs., 8 refs

  12. Potassium Management for Improving Growth and Grain Yield of Maize (Zea mays L.) under Moisture Stress Condition

    Science.gov (United States)

    Amanullah; Iqbal, Asif; Irfanullah; Hidayat, Zeeshan

    2016-01-01

    Potassium (K) fertilizer management is beneficial for improving growth, yield and yield components of field crops under moisture stress condition in semiarid climates. Field experiments were conducted to study the response of maize (Zea mays L., cv. Azam) to foliar and soil applied K during summer 2013 and 2014. The experiments were carried out at the Agronomy Research Farm of The University of Agriculture Peshawar, Northwest Pakistan under limited irrigation (moisture stress) condition. It was concluded from the results that application of foliar K at the rate of 1–3% and foliar Zn at the rate of 0.1–0.2% was more beneficial in terms of better growth, higher yield and yield components of maize under moisture stress condition. Early spray (vegetative stage) resulted in better growth and higher yield than late spray (reproductive stage). Soil K treated plots (rest) plots performed better than control (K not applied) in terms of improved growth, higher yield and yield components of maize crop. The results further demonstrated that increasing the rate of soil applied K up to 90 kg P ha−1 in two equal splits (50% each at sowing and knee height) improve growth and maize productivity under semiarid climates. PMID:27694964

  13. Interstellar Grains

    OpenAIRE

    Draine, B. T.

    2000-01-01

    Our current understanding of interstellar dust is summarized at an introductory level. Submicron-sized interstellar dust grains absorb and scatter light, and reradiate the absorbed energy in the infrared. The grain population spans a range of sizes, from molecules containing only tens of atoms, to particles containing 10^{10} atoms. Most of the grain mass appears to be due to two types of solid, in approximately equal amounts: amorphous silicate mineral, and carbonaceous material. Approximate...

  14. Improvement in the Grain Growth of Plasma-Treated Nano-Sized ZnO Films and Their Characterization.

    Science.gov (United States)

    Chen, Mi; Chou, Ching-Chuan; Lin, Ching-Cheng; Koo, Horng-Show

    2015-11-01

    The well-aligned ZnO nanorods were rapidly grown on an indium tin oxide (ITO)-coated glass substrate using Al-doped ZnO (AZO) thin film as seed layer by the microwave-assisted hydrothermal chemical route. The optimal growth conditions for the well-aligned ZnO nanorods were obtained by modulating H2 plasma pretreatment time for the seed layer and synthesis time for ZnO nanorods. The H2 plasma effect of the seed layer on the alignment, growth rate and crysallinity of ZnO nanods is also demonstrated. The synthesized ZnO nanorods were annealed in atmosphere of N2, O2 and H2 + N2 mixed gas to improve the related physical characteristics, the ZnO nanorods on grapheme/ITO substrate were also investigated. The results show that the alignment and growth rate of ZnO nanorods depends on the physical characteristics and roughness of the seed layer, which can be improved by H2 plasma pretreatment. The average growth rate of ZnO nanorods synthesized by microwave hydrothermal technique is about 2.2 μm/hr which significantly superior to other conventional techniques. After the appropriate N2 annealing treatment, good quality and well-aligned ZnO nanorods, which are single crystal with stacking defects and pyramid or candle shape, were obtained. A fundamental model of the effect of H2 plasma pretreatment on the surface of seed layer and the growth of ZnO nanorods using a microwave-assisted hydrothermal chemical route is also described. PMID:26726662

  15. Enhancement of trapped field in single grain Y–Ba–Cu–O bulk superconductors by a modified top-seeded melt-textured growth

    Science.gov (United States)

    Tang, Tian-wei; Wu, Dong-jie; Xu, Ke-Xi

    2016-08-01

    The modified top-seeded melt-textured growth technique for fabricating single grain Y–Ba–Cu–O (YBCO) bulk superconductors with high field-trapping ability by using modified precursor pellets was reported. The modified precursor pellets are composed of different precursor powders YBa2Cu3O{}7-δ (Y123) + x mol% Y2BaCuO5 (Y211) + 1 wt% CeO2 without any further chemical doping. The modified YBCO bulks up to 25 and 34 mm in diameter were successfully fabricated from the modified precursor pellets. Microstructural observation results showed that the modified YBCO bulk exhibited a homogeneous distribution of Y211 phase particles, which was qualitatively explained by the solute diffusion growth model in combination with the trapping/pushing theory. As a result, it is notable that the peak trapped field values of 0.91 T (maximum 0.96 T) and 1.2 T (maximum 1.28 T) at 77 K were achieved for 25 and 34 mm modified YBCO bulks, respectively. In a word, the results from present work are very helpful to understand the melt growth mechanism and to further improve the properties of YBCO bulk superconductors for practical applications.

  16. Discarded oranges and brewer's spent grains as promoting ingredients for microbial growth by submerged and solid state fermentation of agro-industrial waste mixtures.

    Science.gov (United States)

    Aggelopoulos, Theodoros; Bekatorou, Argyro; Pandey, Ashok; Kanellaki, Maria; Koutinas, Athanasios A

    2013-08-01

    The exploitation of various agro-industrial wastes for microbial cell mass production of Kluyveromyces marxianus, kefir, and Saccharomyces cerevisiae is reported in the present investigation. Specifically, the promotional effect of whole orange pulp on cell growth in mixtures consisting of cheese whey, molasses, and potato pulp in submerged fermentation processes was examined. A 2- to 3-fold increase of cell mass was observed in the presence of orange pulp. Likewise, the promotional effect of brewer's spent grains on cell growth in solid state fermentation of mixtures of whey, molasses, potato pulp, malt spent rootlets, and orange pulp was examined. The cell mass was increased by 3-fold for K. marxianus and 2-fold for S. cerevisiae in the presence of these substrates, proving their suitability for single-cell protein production without the need for extra nutrients. Cell growth kinetics were also studied by measurements of cell counts at various time intervals at different concentrations of added orange pulp. The protein content of the fermented substrates was increased substantially, indicating potential use of mixed agro-industrial wastes of negligible cost, as protein-enriched livestock feed, achieving at the same time creation of added value and waste minimization. PMID:23780341

  17. Infrared Spectroscopic Survey of the Quiescent Medium of Nearby Clouds: I. Ice Formation and Grain Growth in Lupus

    CERN Document Server

    Boogert, A C A; Knez, C; Öberg, K I; Mundy, L G; Pendleton, Y J; Tielens, A G G M; van Dishoeck, E F

    2013-01-01

    Infrared photometry and spectroscopy (1-25 um) of background stars reddened by the Lupus molecular cloud complex are used to determine the properties of the grains and the composition of the ices before they are incorporated into circumstellar envelopes and disks. H2O ices form at extinctions of Ak=0.25+/-0.07 mag (Av=2.1+/-0.6). Such a low ice formation threshold is consistent with the absence of nearby hot stars. Overall, the Lupus clouds are in an early chemical phase. The abundance of H2O ice (2.3+/-0.1*10^-5 relative to Nh) is typical for quiescent regions, but lower by a factor of 3-4 compared to dense envelopes of YSOs. The low solid CH3OH abundance (5 um) continuum extinction relative to Ak increases as a function of Ak. Most Lupus lines of sight are well fitted with empirically derived extinction curves corresponding to Rv~ 3.5 (Ak=0.71) and Rv~5.0 (Ak=1.47). For lines of sight with Ak>1.0 mag, the tau9.7/Ak ratio is a factor of 2 lower compared to the diffuse medium. Below 1.0 mag, values scatter be...

  18. Effect of Irrigation Timing on Root Zone Soil Temperature, Root Growth and Grain Yield and Chemical Composition in Corn

    OpenAIRE

    Xuejun Dong; Wenwei Xu; Yongjiang Zhang; Daniel I. Leskovar

    2016-01-01

    High air temperatures during the crop growing season can reduce harvestable yields in major agronomic crops worldwide. Repeated and prolonged high night air temperature stress may compromise plant growth and yield. Crop varieties with improved heat tolerance traits as well as crop management strategies at the farm scale are thus needed for climate change mitigation. Crop yield is especially sensitive to night-time warming trends. Current studies are mostly directed to the elevated night-time ...

  19. Effects of feeding corn modified wet distillers grain plus solubles co-ensiled with chopped whole plant corn on heifer growth performance and diet digestibility in beef cattle.

    Science.gov (United States)

    Arias, R P; Unruh-Snyder, L J; Scholljegerdes, E J; Baird, A N; Johnson, K D; Buckmaster, D; Lemenager, R P; Lake, S L

    2013-09-01

    Two experiments were conducted to evaluate the effect of feeding corn modified wet distillers grain plus solubles (MWDGS; 48% DM) co-ensiled with chopped whole plant corn (WC) on growth performance, dietary intake, and nutrient digestibility of beef cattle. In Exp. 1, 96 Angus-crossed heifers (2 yr old; 522 ± 49.1 kg BW; 5.3 ± 0.1 BCS) were stratified and blocked according to BW and stratified by BCS in each block in a randomized complete block design (24 pens; 4 heifers/pen; 6 treatment replications). Groups were assigned to 1 of 4 dietary treatments for a 62 d trial. Treatments were 1) corn silage (CS) and soybean meal (CON), 2) MWDGS co-ensiled with chopped whole plant corn (WC; CO-EN), 3) CS mixed with MWDGS at feeding (CS+WDG), and 4) CS mixed with dry distillers grain plus solubles (DDGS) at feeding (CS+DDG). In Exp. 2, 4 crossbred beef steers (initial BW = 278 ± 18 kg) fitted with permanent ruminal cannulas were used in a balanced 4 × 4 Latin square to test the effects of feeding MWDGS co-ensiled with WC on DM intake, ruminal fermentation characteristics, and total tract digestibility. There were four 14-d periods, with 10 d for diet adaptation and 4 d for samples collection. Orthogonal contrasts were used and compared CON vs. diets containing distillers grains (DGD), CO-EN vs. diets where distillers grains were mixed at feeding (MIX), and CS+WDG vs. CS+DDG. In Exp. 1, the CON fed heifers resulted in greater G:F (P = 0.04) compared with those fed DGD. However, ADG (P = 0.03), final BW (P = 0.04), and BW gain (P = 0.03) were greatest for DGD diets compared with CON and greatest (P = 0.04) for CO-EN when compared with MIX. Apart from a slightly greater acetate concentration (P = 0.05), which resulted in a greater acetate to propionate ratio (P = 0.03) for the CON diet compared with DGD, no important differences were observed on intake, diet digestibility, or fermentation characteristics when comparing the CON treatment with DGD or when comparing CS

  20. Sharp Goss orientation and large magnetostriction in the rolled columnar-grained Fe–Ga alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Chao; Li, Jiheng; Zhang, Wenlan; Bao, Xiaoqian; Gao, Xuexu, E-mail: gaox@skl.ustb.edu.cn

    2015-01-15

    In this work, the 〈1 0 0〉 directional solidified feedstock slabs were used to produce the rolled Fe–Ga sheets, and sharp Goss orientation was developed in the 0.3 mm sheets after annealing processes. The area fraction of Goss grains in the annealed binary Fe–Ga sheets approached to 62.4% without abnormal grain growth, accompanied with a maximum magnetostriction (λ{sub //}−λ{sub ⊥}) of 199 ppm. The addition of only 0.1 at% NbC notably promoted the abnormal Goss grain growth without sulfur annealing, and large single-crystal-like grains, up to several centimeters, were obtained with few island-like grains after sulfur annealing and final Ar/H{sub 2} annealing processes. High magnetostriction (λ{sub //}−λ{sub ⊥}) of 245 ppm with little deviation was achieved in the (Fe{sub 83}Ga{sub 17}){sub 99.9}(NbC){sub 0.1} sheets, and a large magnetostrictive strain (λ{sub //}) up to 243 ppm under no pre-stress was observed with an applied magnetic field along the rolling direction. - Highlights: • The 〈1 0 0〉 oriented feedstock slabs were used to prepare Goss oriented Fe–Ga sheets. • Abnormal Goss grain growth was observed in the 0.3 mm sheets with only 0.1 at% NbC. • A high λ{sub //} of 243 ppm under no pre-stress was observed along the RD.

  1. Route and Regulation of Zinc, Cadmium, and Iron Transport in Rice Plants (Oryza sativa L.) during Vegetative Growth and Grain Filling: Metal Transporters, Metal Speciation, Grain Cd Reduction and Zn and Fe Biofortification.

    Science.gov (United States)

    Yoneyama, Tadakatsu; Ishikawa, Satoru; Fujimaki, Shu

    2015-01-01

    Zinc (Zn) and iron (Fe) are essential but are sometimes deficient in humans, while cadmium (Cd) is toxic if it accumulates in the liver and kidneys at high levels. All three are contained in the grains of rice, a staple cereal. Zn and Fe concentrations in rice grains harvested under different levels of soil/hydroponic metals are known to change only within a small range, while Cd concentrations show greater changes. To clarify the mechanisms underlying such different metal contents, we synthesized information on the routes of metal transport and accumulation in rice plants by examining metal speciation, metal transporters, and the xylem-to-phloem transport system. At grain-filling, Zn and Cd ascending in xylem sap are transferred to the phloem by the xylem-to-phloem transport system operating at stem nodes. Grain Fe is largely derived from the leaves by remobilization. Zn and Fe concentrations in phloem-sap and grains are regulated within a small range, while Cd concentrations vary depending on xylem supply. Transgenic techniques to increase concentrations of the metal chelators (nicotianamine, 2'-deoxymugineic acid) are useful in increasing grain Zn and Fe concentrations. The elimination of OsNRAMP5 Cd-uptake transporter and the enhancement of root cell vacuolar Cd sequestration reduce uptake and root-to-shoot transport, respectively, resulting in a reduction of grain Cd accumulation. PMID:26287170

  2. Route and Regulation of Zinc, Cadmium, and Iron Transport in Rice Plants (Oryza sativa L. during Vegetative Growth and Grain Filling: Metal Transporters, Metal Speciation, Grain Cd Reduction and Zn and Fe Biofortification

    Directory of Open Access Journals (Sweden)

    Tadakatsu Yoneyama

    2015-08-01

    Full Text Available Zinc (Zn and iron (Fe are essential but are sometimes deficient in humans, while cadmium (Cd is toxic if it accumulates in the liver and kidneys at high levels. All three are contained in the grains of rice, a staple cereal. Zn and Fe concentrations in rice grains harvested under different levels of soil/hydroponic metals are known to change only within a small range, while Cd concentrations show greater changes. To clarify the mechanisms underlying such different metal contents, we synthesized information on the routes of metal transport and accumulation in rice plants by examining metal speciation, metal transporters, and the xylem-to-phloem transport system. At grain-filling, Zn and Cd ascending in xylem sap are transferred to the phloem by the xylem-to-phloem transport system operating at stem nodes. Grain Fe is largely derived from the leaves by remobilization. Zn and Fe concentrations in phloem-sap and grains are regulated within a small range, while Cd concentrations vary depending on xylem supply. Transgenic techniques to increase concentrations of the metal chelators (nicotianamine, 2′-deoxymugineic acid are useful in increasing grain Zn and Fe concentrations. The elimination of OsNRAMP5 Cd-uptake transporter and the enhancement of root cell vacuolar Cd sequestration reduce uptake and root-to-shoot transport, respectively, resulting in a reduction of grain Cd accumulation.

  3. Effect of wheat dried distillers grains with solubles and fibrolytic enzymes on ruminal fermentation, digestibility, growth performance, and feeding behavior of beef cattle.

    Science.gov (United States)

    He, Z X; Walker, N D; McAllister, T A; Yang, W Z

    2015-03-01

    Two experiments were conducted to evaluate the effect of wheat dried distillers grains with solubles (DDGS) and fibrolytic enzymes (FE) on ruminal fermentation, in situ ruminal and in vivo total tract digestibility, growth performance, and feeding behavior of growing beef cattle. In Exp. 1, 6 ruminally cannulated Angus heifers (average BW of 794 ± 44.2 kg) were used in a 6 × 6 Latin square design with 2 × 3 factorial arrangement of treatments. Treatments were a control diet consisting of 50% barley silage, 10% grass hay, and 40% barley grain-based concentrate (CON) and the CON with 15% DDGS substituted for barley grain (WDG) combined with either 0, 1, or 2 mL FE/kg diet DM, respectively. Inclusion of DDGS increased total tract digestibility of CP ( effects of DDGS inclusion or FE on ruminal pH or VFA concentration except that propionate was greater ( = 0.04) with the WDG. In situ ruminal DM and NDF disappearance of barley silage was greater ( < 0.04) in heifers fed the WDG than in heifers fed the CON after 24 h of incubation. Increasing FE linearly ( = 0.03) increased in situ NDF disappearance of barley silage after 24 h of incubation. In Exp. 2, 120 weaned steers (initial BW of 289 ± 11.0 kg) were fed diets similar to those in Exp. 1. The steers fed the WDG had greater ( < 0.01) final BW, ADG, DMI, and G:F compared with steers fed the CON. Increasing FE did not alter ADG or G:F but tended ( < 0.07) to linearly decrease DMI. There were interactions ( < 0.02) between DDGS and FE on eating rate and the time spent at the feed bunk. Supplementing FE decreased ( < 0.01) time at the bunk and increased ( < 0.01) eating rate for steers fed the WDG but not for steers fed the CON. Eating rate ( < 0.01) and meal frequency ( = 0.02) were greater but eating duration was shorter ( < 0.01) for steers fed the WDG than for those fed the CON. These results indicate that inclusion of wheat DDGS in a growing diet increased total tract digestibility of NDF and CP and improved the

  4. Effect of rice and other cereal grains on growth performance, pig removal, and antibiotic treatment of weaned pigs under commercial conditions.

    Science.gov (United States)

    Che, T M; Perez, V G; Song, M; Pettigrew, J E

    2012-12-01

    Three experiments were conducted to evaluate effects of rice and other cereal grains on growth performance and health of weanling pigs. Pigs (1,008 in Exp. 1 and 3 and 1,004 in Exp. 2; 21 d old) with an initial BW of 5.8 ± 1.0 kg were used. Pigs in each experiment were divided into 3 BW blocks (heavy, medium, or light) in each of 4 rooms, resulting in 12 blocks per experiment. Each pen within a block had 20 or 21 pigs and equal sex distribution. Pens were allotted to dietary treatments in a randomized complete block design. Pigs were fed in a 4-phase feeding program with Phases 1 and 2 of 1 wk each and Phases 3 and 4 of 2 wk each. Diets were formulated to meet the same nutritional standards within each phase. In Exp. 1, effects of different cereal grains on pig performance and removal rate (mortality plus morbidity) were investigated. Pigs were fed 4 diets based on corn, barley, rolled oats, or rice as the only cereal grain. Over a 6-wk period, the ADG of pigs fed rice was greater (P oats. Pigs fed corn or rice did not differ in ADFI, which was greater (P oats (P < 0.05), and tended to be less than those pigs fed corn (P = 0.075). Experiment 2 was conducted to determine if the benefits observed in Exp. 1 could be obtained by feeding rice for less than 6 wk. Treatments included rice diets fed for 0, 1, 2, or 4 wk before changing to corn diets. All pigs received a common diet during wk 5 and 6. Pig performance and antibiotic treatments did not differ among dietary treatments. However, pigs fed rice for 1, 2, or 4 wk had a reduced overall removal rate (P < 0.05) compared with those fed corn. Experiment 3 was conducted to investigate if the amount of rice fed in wk 1 could be reduced without reducing pig performance. Rice replaced 0, 50, 75, or 100% of corn in Phase 1 diets. All pigs received a common diet from wk 2 to 6. No differences in pig performance or antibiotic treatments among dietary treatments were observed. However, pigs fed the diet with 100% rice had a

  5. The extent of grain yield and plant growth enhancement by plant growth-promoting broad-spectrum Streptomyces sp. in chickpea

    OpenAIRE

    Gopalakrishnan, Subramaniam; Srinivas, Vadlamudi; Alekhya, Gottumukkala; Prakash, Bandikinda; Kudapa, Himabindu; Rathore, Abhishek; Varshney, Rajeev Kumar

    2015-01-01

    The physiological and molecular responses of five strains of Streptomyces sp. (CAI-17, CAI-68, CAI-78, KAI-26 and KAI-27), with their proven potential for charcoal rot disease control in sorghum and plant growth-promotion (PGP) in sorghum and rice, were studied to understand the mechanisms causing the beneficial effects. In this investigation, those five strains were evaluated for their PGP capabilities in chickpea in the 2012–13 and 2013–14 post-rainy seasons. All of the Streptomyces sp. str...

  6. Route and Regulation of Zinc, Cadmium, and Iron Transport in Rice Plants (Oryza sativa L.) during Vegetative Growth and Grain Filling: Metal Transporters, Metal Speciation, Grain Cd Reduction and Zn and Fe Biofortification

    OpenAIRE

    Tadakatsu Yoneyama; Satoru Ishikawa; Shu Fujimaki

    2015-01-01

    Zinc (Zn) and iron (Fe) are essential but are sometimes deficient in humans, while cadmium (Cd) is toxic if it accumulates in the liver and kidneys at high levels. All three are contained in the grains of rice, a staple cereal. Zn and Fe concentrations in rice grains harvested under different levels of soil/hydroponic metals are known to change only within a small range, while Cd concentrations show greater changes. To clarify the mechanisms underlying such different metal contents, we synt...

  7. Feeding distillers dried grains in replacement of forage in limit-fed dairy heifer rations: Effects on growth performance, rumen fermentation, and total-tract digestibility of nutrients.

    Science.gov (United States)

    Manthey, A K; Anderson, J L; Perry, G A

    2016-09-01

    The objective of this study was to determine the effects of increasing dietary concentration of distillers dried grains (DDGS) in dairy heifer rations. A 16-wk randomized complete block design study was conducted using 48 Holstein heifers [199±2 d of age; body weight (BW) 206±2kg] to evaluate effects of dietary treatment on dry matter (DM) intake, average daily gain, growth performance, rumen fermentation, and nutrient digestibility. Treatments were (1) 30% DDGS with the diet fed at 2.65% of BW, (2) 40% DDGS with the diet fed at 2.50% of BW, and (3) 50% DDGS with the diet fed at 2.35% of BW. The remainder of the diet consisted of grass hay and 1.5% mineral mix. Heifers were individually limit-fed using Calan gates. Heifers were weighed every 2 wk and the ration amount offered was adjusted accordingly. Frame measurements and body condition score were recorded every 2wk. Rumen fluid was collected via esophageal tubing during wk 12 and 16 for pH, ammonia N, and volatile fatty acid analysis. Total-tract digestibility of nutrients was evaluated during wk 16 using fecal grab sampling. No treatment by week interactions were found for any of the growth parameters measured, and growth parameters did not differ among treatments. Heifer DM intake linearly decreased with increasing concentrations of DDGS. Body weight and average daily gain were similar among treatments, whereas gain:feed linearly increased across treatments, with a tendency for a treatment by time interaction. As the dietary concentrations of DDGS increased, rumen ammonia N linearly increased. Acetate proportion and acetate:propionate linearly decreased as DDGS increased, whereas propionate linearly increased. There were treatment by time interactions for propionate proportion and acetate:propionate. Increasing dietary concentrations of DDGS linearly increased total-tract digestibility of DM, organic matter, and crude protein. Limit-feeding diets with greater concentrations of DDGS improved gain:feed and

  8. Frequency of wet brewers grains supplementation during late gestation of beef cows and its effects on offspring postnatal growth and immunity.

    Science.gov (United States)

    Moriel, P; Artioli, L F A; Piccolo, M B; Marques, R S; Poore, M H; Cooke, R F

    2016-06-01

    Our objectives were to evaluate postnatal growth and measurements of innate and humoral immunity of beef calves born to dams fed wet brewers grains (WBG) daily or 3 times weekly during late gestation. On d 0 (approximately 60 d before calving), 28 multiparous, spring-calving Angus cows (BW = 578 ± 19 kg; age = 4.7 ± 0.65 yr; BCS = 7.0 ± 0.18) were stratified by sire, age, BW, and BCS and then randomly allocated into 1 of 14 drylot pens (2 cows/pen; 18 by 3 m; 27 m/cow). Cows were offered ground tall fescue hay ad libitum and received similar weekly WBG supplementation (DMI = 0.5% of BW multiplied by 7 d). Treatments were randomly assigned to pens (7 pens/treatment) and consisted of cows receiving WBG supplementation daily (S7; weekly DMI of WBG divided by 7 d) or 3 times weekly (S3; weekly DMI of WBG divided by 3 d; Mondays, Wednesdays, and Fridays) from d 0 until calving. Cow-calf pairs were managed as a single group on tall fescue pastures from calving to weaning (d 226). Calves were immediately submitted to a preconditioning period from d 226 to 266 and vaccinated against infectious bovine rhinotracheitis, bovine viral diarrhea virus, , and on d 231 and 245. Decreasing the frequency of WBG supplementation did not impact ( ≥ 0.21) precalving intake of total DM, CP, and TDN; BW and BCS change; overall plasma cortisol concentrations; and postcalving growth and pregnancy rate of cows. Overall plasma concentrations of glucose and insulin did not differ ( ≥ 0.28) between S3 and S7 cows, whereas S3 cows had greater ( = 0.002) plasma glucose concentrations and tended ( = 0.06) to have greater plasma insulin concentrations on days they were not fed WBG vs. days of WBG supplementation. Calf plasma concentrations of haptoglobin and cortisol at birth but not serum IgG ( = 0.63) tended ( = 0.10) to be greater for S3 vs. S7 calves. However, additional calf growth and immunity variables obtained during pre- and postweaning phases did not differ between S3 and S7 calves

  9. Abnormal sex chromosome constitution and longitudinal growth: serum levels of insulin-like growth factor (IGF)-I, IGF binding protein-3, luteinizing hormone, and testosterone in 109 males with 47,XXY, 47,XYY, or sex-determining region of the Y chromosome (SRY)-positive 46,XX karyotypes

    DEFF Research Database (Denmark)

    Aksglaede, L.; Skakkebaek, N.E.; Juul, A.

    2008-01-01

    CONTEXT: Growth is a highly complex process regulated by the interaction between sex steroids and the GH IGF-axis. However, other factors such as sex chromosome-related genes play independent roles. AIM: The aim of the study was to evaluate the role of abnormal chromosome constitution for longitu...

  10. Growth and yield of two grain crops on sites former covered with euca-lypt plantations in Koga Watershed, northwestern Ethiopia

    Institute of Scientific and Technical Information of China (English)

    Desalegn Tadele; Demel Teketay

    2014-01-01

    Farmers in the highlands of Ethiopia often plant Eucalyptus on their farmlands. However, growing Eucalyptus, especially on farm-lands suitable for crop production has become a great concern due to its alleged long-term site effects. Our study was conducted at Koga water-shed, Mecha District, northwestern Ethiopia to investigate whether crop-lands afforested with Eucalyptus camaldulensis Dehnh. can be restored for annual crop production after tree harvest. We compared growth and yield of two agricultural crops, barley (Hordeum vulgare L.) and finger millet (Eleusine coracana (L.) Gaertn.), grown in clear-felled stands of E. camaldulensis and continuously cultivated croplands at twelve paired farmlands under a conventional farming system. Plant height and dry matter production were evaluated as indices of crop growth, while grain weight was evaluated as an index of crop yield. Crop growth and yield measurements averaged over all farmlands differed between land-use types. For both crops, plants grown on clear-felled stands were taller than on croplands. Dry matter production and yield were also significantly greater in crops cultivated on clear-felled stands. Cropland aboveground and belowground dry matter productions were lower by 31.8 and 25.4%for barley and 32.8%and 37%for finger millet, respectively. Clear-felled stands gave an average yield of 2.91 t⋅ha-1 for barley and 3.27 t⋅ha-1 for finger millet while cropland gave a yield of 1.97 and 2.31 t⋅ha-1 for barley and finger millet, respectively. Farmers also responded that farm plots on former eucalypt plantations showed greater crop growth and yield than did continuously cultivated croplands. Farmers perceived that Eucalyptus plantations improved soil fertility and they preferred clear-felled stands for crop production and wished to plant Eucalyptus on their farmlands. Our results suggest that conversion of agricultural lands to Eucalyptus plantations can increase post-felling yields of cereal crops.

  11. Effects of different methods of wheat grain processing on skeletal growth, blood metabolites, feed consumption and digestion in neonatal Holstein calves

    Directory of Open Access Journals (Sweden)

    S. S. Mirghaffari,

    2012-03-01

    Full Text Available Fifty six neonatal Holstein calves (22 male and 34 female were fed calf starters and post weaning diets containing 35 and 21.90% Popped (PW, steam flaked (SFW, dry-rolled (DRW or ground (GW to 12 weeks of age. Particle size distribution of processed wheat grains, skeletal growth measures, starter digestibility, starter intake, health status, and blood metabolites of neonatal calves were assessed in weeks 4, 8 and 12 to assess rumen development and find the optimum method of wheat processing for calves. The experiment started when calves were 3 ± 1 d old and studied for 90 days. Calves were weaned at the end of 9th week and a post weaning specific starter diets were fed for one month. PW and SFW dramatically decreased fine particles in comparison to GW or DRW. PW had the most proportion of larger particles (93.52% >3.38 mm where GW had the finest texture (70.71% <2 mm. Health status parameters of calves did not affected by treatments, but respiratory index was affected by time. Skeletal growth measures including body length, body barrel, wither height and hip width did not affected by treatments, but these measures progressed by age. Calves received PW had the highest body weight and daily gain, but feed; gain ratio was not affected by treatments. These parameters were also affected by age. Although, calves received DRW had the lowest starter intake, but the highest digestibility coefficients for dry matter, organic matter, crude protein, NDF and energy. This higher digestibility was attributed to lower starter intake resulted in probably higher rumen retention time and thus the most rumen degradation of nutrients. Calves received PW, had the highest serum glucose, BHBA and insulin concentrations which may indicate that PW could cause a better rumen development and performance in comparison with other types of processed wheat.

  12. Effects of local structure on helium bubble growth in bulk and at grain boundaries of bcc iron: A molecular dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Li [Univ. of Electronic Science and Technology of China, Chengdu (China); Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gao, Fei [Univ. of Michigan, Ann Arbor, MI (United States); Kurtz, Richard J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zu, Xiaotao [Univ. of Electronic Science and Technology of China, Chengdu (China); Peng, S. M. [China Academy of Engineering Physics, Mianyang (China); Long, X. G. [China Academy of Engineering Physics, Mianyang (China); Zhou, X. S. [China Academy of Engineering Physics, Mianyang (China)

    2015-07-15

    The nucleation and growth of helium (He) bubbles in the bulk and at Σ3 <110> {112} and Σ73b <110> {661} grain boundaries (GBs) in bcc iron have been investigated using molecular dynamics simulations. The results show that a 1/2 <111> {111} dislocation loop is formed with the sequential collection of <111> interstitial crowdions at the periphery of the He cluster and is eventually emitted from the He cluster. Insertion of 45 He atoms into a He cluster leads to the formation of a 1/2 <111> dislocation loop in Σ3 GB. It is of interest to notice that the transition of a dislocation segment through the GB leads to the formation of a step at the GB plane following the loop formation, accounting for the formation of a residual GB defect. A 1/2 <111> loop, with a {110} habit plane, is emitted with further increase of the He bubble size in the Σ3 GB. In contrast, the sequential insertion of He atoms in Σ73b GB continuously emits self-interstitial atoms (SIAs), but these SIAs rearrange at the core of the inherent GB dislocation, instead of forming a dislocation loop, which leads the GB dislocation to propagate along the [1¯1¯ 1 2] direction. In the bulk and Σ3 GB, the He bubble exhibits three-dimensionally spherical shape, but it forms longitudinal shape along the dislocation line in the Σ73 GB, a shape commonly observed at GBs in experiments.

  13. In operando spatiotemporal study of Li(2)O(2) grain growth and its distribution inside operating Li-O(2) batteries.

    Science.gov (United States)

    Shui, Jiang-Lan; Okasinski, John S; Chen, Chen; Almer, Jonathan D; Liu, Di-Jia

    2014-02-01

    Nanocrystalline lithium peroxide (Li2 O2 ) is considered to play a critical role in the redox chemistry during the discharge-charge cycling of the Li-O2 batteries. In this report, a spatially resolved, real-time synchrotron X-ray diffraction technique was applied to study the cyclic formation/decomposition of Li2 O2 crystallites in an operating Li-O2 cell. The evaluation of Li2 O2 grain size, concentration, and spatial distribution inside the cathode is demonstrated under the actual cycling conditions. The study not only unambiguously proved the reversibility of the Li2 O2 redox reaction during reduction and evolution of O2 , but also allowed for the concentration and dimension growths of the peroxide nanocrystallites to be accurately measured at different regions within the cathode. The results provide important insights for future investigation on mass and charge transport properties in Li2 O2 and improvement in cathode structure and material design. PMID:24399807

  14. Electronic properties of grains and grain boundaries in graphene grown by chemical vapor deposition

    OpenAIRE

    Jauregui, Luis A.; Cao, Helin; Wu, Wei; Yu, Qingkai; Chen, Yong P.

    2011-01-01

    We synthesize hexagonal shaped single-crystal graphene, with edges parallel to the zig-zag orientations, by ambient pressure CVD on polycrystalline Cu foils. We measure the electronic properties of such grains as well as of individual graphene grain boundaries, formed when two grains merged during the growth. The grain boundaries are visualized using Raman mapping of the D band intensity, and we show that individual boundaries between coalesced grains impede electrical transport in graphene a...

  15. Urine - abnormal color

    Science.gov (United States)

    ... medlineplus.gov/ency/article/003139.htm Urine - abnormal color To use the sharing features on this page, please enable JavaScript. The usual color of urine is straw-yellow. Abnormally colored urine ...

  16. 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.

  17. Biofuel feedstock and blended coproducts compared with deoiled corn distillers grains in feedlot diets: Effects on cattle growth performance, apparent total tract nutrient digestibility, and carcass characteristics.

    Science.gov (United States)

    Opheim, T L; Campanili, P R B; Lemos, B J M; Ovinge, L A; Baggerman, J O; McCuistion, K C; Galyean, M L; Sarturi, J O; Trojan, S J

    2016-01-01

    Crossbred steers (British × Continental; = 192; initial BW 391 ± 28 kg) were used to evaluate the effects of feeding ethanol coproducts on feedlot cattle growth performance, apparent nutrient digestibility, and carcass characteristics. Steers were blocked by initial BW and assigned randomly to 1 of 6 dietary treatments within block. Treatments (replicated in 8 pens with 4 steers/pen) included 1) control, steam-flaked corn-based diet (CTL), 2) corn dried distillers grains with solubles (DGS; DRY-C), 3) deoiled corn dried DGS (DRY-CLF), 4) blended 50/50 corn/sorghum dried DGS (DRY-C/S), 5) sorghum dried DGS (DRY-S), and 6) sorghum wet DGS (WET-S). Inclusion of DGS was 25% (DM basis). The DGS diets were isonitrogenous, CTL was formulated for 13.5% CP, and all diets were balanced for ether extract. Final shrunk BW, ADG, and DMI did not differ among CTL and DGS treatments ( ≥ 0.19). Overall G:F did not differ from CTL for DRY-C, DRY-CLF, or WET-S ( ≥ 0.12); however, G:F was 9.6% less for DRY-S compared with CTL ( < 0.01) and tended ( = 0.09) to be less for DRY-C/S than CTL. For grain source, ADG and G:F were less for DRY-S vs. DRY-C ( < 0.05), but blending DRY-C/S tended ( = 0.07) to increase ADG and increased ( = 0.05) carcass-adjusted G:F vs. DRY-S. For WET-S, final BW and ADG were greater ( < 0.05), and G:F tended ( = 0.06) to be greater than for DRY-S. There was no difference in ADG, DMI, or G:F of steers fed DRY-C vs. DRY-CLF ( ≥ 0.35). Apparent DM and OM digestibility did not differ for CTL, DRY-C, DRY-CLF, and WET-S ( ≥ 0.30) but were lower for DRY-C/S and DRY-S ( < 0.05). Nutrient digestibility was lower for DRY-S vs. DRY-C ( < 0.01), but apparent digestibility of OM, DM, NDF, ADF, CP, ether extract, and starch were increased ( < 0.01) for DRY-C/S vs. DRY-S. Although starch digestibility did not differ between DRY-S and WET-S ( 0.18), digestibility of other measured nutrients was greater for WET-S vs. DRY-S ( < 0.01). Ether extract digestibility was

  18. Effects of late gestation distillers grains supplementation on fall-calving beef cow performance and steer calf growth and carcass characteristics.

    Science.gov (United States)

    Wilson, T B; Schroeder, A R; Ireland, F A; Faulkner, D B; Shike, D W

    2015-10-01

    Fall-calving, mature Angus and Simmental × Angus cows ( = 251 total) and their progeny were used to evaluate the effects of late gestation dried distillers grains plus solubles (DDGS) supplementation on cow performance and progeny growth and carcass characteristics. Cows were blocked by breed and allotted to 12 tall fescue pastures (6.8 ha average). Pastures were randomly assigned to 1 of 2 treatments: cows were offered 2.1 kg DM DDGS·cow·d (SUP; CP = 23%, fat = 7%; = 6 pastures) or were not offered a supplement (CON; = 6 pastures) 69 ± 9 d before expected calving date. Cows remained on treatments until calving. Once weekly, cows that had calved were removed from treatment pastures and were moved to new tall fescue pastures (21.6 ha average) where cows from both treatments were comingled without further supplementation. Cows ( = 74) were removed from study for calving more than 30 d after expected calving date, calf loss and injury, or euthanasia. Cow BW and BCS were recorded at the beginning of the supplementation period, after calving, and at breeding. Calf BW was taken at birth and early weaning (82 ± 14 d of age). After weaning, 71 steer progeny (representative of dam breed and treatment pastures) were transitioned to a common feedlot diet with individual feed intake monitored using the GrowSafe feeding system. Steers were slaughtered at 47 ± 4 d after a minimum 12th rib fat thickness (back fat) estimation of 0.6 cm, with cattle being shipped in 3 groups. Forage availability was not different between treatments ( = 0.69). Cows offered SUP gained more BW and BCS ( ≤ 0.02) during the supplementation period. There were no differences ( ≥ 0.12) in calving date, calf birth or weaning BW, or preweaning ADG. Cow BW at breeding was not different ( = 0.19); however, BCS at breeding was greater ( carcass characteristics. PMID:26523577

  19. Mechanical properties and radiation tolerance of ultrafine grained and nanocrystalline metals

    Science.gov (United States)

    Sun, Cheng

    Austenitic stainless steels are commonly used in nuclear reactors and have been considered as potential structural materials in fusion reactors due to their excellent corrosion resistance, good creep and fatigue resistance at elevated temperatures, but their relatively low yield strength and poor radiation tolerance hinder their applications in high dose radiation environments. High angle grain boundaries have long been postulated as sinks for radiation-induced defects, such as bubbles, voids, and dislocation loops. Here we provide experimental evidence that high angle grain boundaries can effectively remove radiation-induced defects. The equal channel angular pressing (ECAP) technique was used to produce ultrafine grained Fe-Cr-Ni alloy. Mechanical properties of the alloy were studied at elevated temperature by tensile tests and in situ neutron scattering measurements. Enhanced dynamic recovery process at elevated temperature due to dislocation climb lowers the strain hardening rate and ductility of ultrafine grained Fe-Cr-Ni alloy. Thermal stability of the ultrafine grained Fe-Cr-Ni alloy was examined by ex situ annealing and in situ heating within a transmission electron microscope. Abnormal grain growth at 827 K (600°C) is attributed to deformation-induced martensite, located at the triple junctions of grains. Helium ion irradiation studies on Fe-Cr-Ni alloy show that the density of He bubbles, dislocation loops, as well as irradiation hardening are reduced by grain refinement. In addition, we provide direct evidence, via in situ Kr ion irradiation within a transmission electron microscope, that high angle grain boundaries in nanocrystalline Ni can effectively absorb irradiation-induced dislocation loops and segments. The density and size of dislocation loops in irradiated nanocrystalline Ni were merely half of those in irradiated coarse grained Ni. The results imply that irradiation tolerance in bulk metals can be effectively enhanced by microstructure

  20. Supercube grains leading to a strong cube texture and a broad grain size distribution after recrystallization

    Science.gov (United States)

    Lin, F. X.; Zhang, Y. B.; Pantleon, W.; Jensen, D. Juul

    2015-08-01

    This work revisits the classical subject of recrystallization of cold-rolled copper. Two characterization techniques are combined: three-dimensional X-ray diffraction using synchrotron X-rays, which is used to measure the growth kinetics of individual grains in situ, and electron backscatter diffraction, which is used for statistical analysis of the microstructural evolution. As the most striking result, the strong cube texture after recrystallization is found to be related to a few super large cube grains, which were named supercube grains. These few supercube grains become large due to higher growth rates. However, most other cube grains do not grow preferentially. Because of the few supercube grains, the grain size distribution after recrystallization is broad. Reasons for the higher growth rates of supercube grains are discussed, and are related to the local deformed microstructure.

  1. Supercube grains leading to a strong cube texture and a broad grain size distribution after recrystallization

    DEFF Research Database (Denmark)

    Lin, F.X.; Zhang, Y. B.; Pantleon, W.;

    2015-01-01

    diffraction, which is used for statistical analysis of the microstructural evolution. As the most striking result, the strong cube texture after recrystallization is found to be related to a few super large cube grains, which were named supercube grains. These few supercube grains become large due to higher......This work revisits the classical subject of recrystallization of cold-rolled copper. Two characterization techniques are combined: three-dimensional X-ray diffraction using synchrotron X-rays, which is used to measure the growth kinetics of individual grains in situ, and electron backscatter...... growth rates. However, most other cube grains do not grow preferentially. Because of the few supercube grains, the grain size distribution after recrystallization is broad. Reasons for the higher growth rates of supercube grains are discussed, and are related to the local deformed microstructure....

  2. Sistemas de manejo de plantas daninhas no desenvolvimento e na produtividade da soja Burndown systems on growth and grain yield in soybeans in Paraná State, Brazil

    Directory of Open Access Journals (Sweden)

    Jamil Constantin

    2009-01-01

    glyphosate occurred within 48 hours prior to sowing. The trials were developed in 2003/2004 growing season, in six localities in Paraná State: Sertãozinho, Campo Mourão, Iretama, Pitanga, Boa Esperança, and Mamborê, in areas with high density of weeds preceding no-till soybean sowing. Evaluations related to weed control and soybean development and grain yield were performed. MA burndown systems provided improved control of weeds after crop emergence. Soybean plants from AP areas were shorter, in comparison to ME, evidencing a delay in the shoot growth. Reduction of grain yield was verified for all localities when AP burndown system was adopted, with reductions between 15% and 50%.

  3. EFFECT OF TREATMENT WITH MOLD INHIBITORS ON PLANT GROWTH OF CORN AND SOME NUTRITIONAL COMPONENTS OF STORED GRAINS, INFECTED WITH A. FLAVUS AND F. VERTICILLOIDES

    Directory of Open Access Journals (Sweden)

    Mervat S. Youssef

    2012-12-01

    Full Text Available Planting sterilized corn grains in soil, treated with the mold inhibitors Fix-a-tox (FAT or Antitox Plus (AP resulted, in cases, in dwarfed and malformed corn plants and in the development of deformed, bone-shaped and grain-free corn cobs. Moreover, treating corn grains with the mold inhibitors before storage for one month caused significant changes in some nutritional components of corn grains, i.e. proteins, aminoacids, crude fibers, moisture, fats, ash and carbohydrates. Insignificant differences in protein percetage were detected between control inoculated with Aspergillus flavus and those treated with butyl hydroxyanisole (BHA antioxidant or FAT treatments, whereas ground clove significantly reduced protein content. In corn grains inoculated with Fusariumverticillioides, previous treatment with FAT resulted in significant reduction in the content of proline, aspartic acid, cysteine, valine, isoleucine and leucine, whereas treatment with BHA significantly reduced the content of threonine, serine, glutamic, glycine, alanine, phenylalanine and tyrosine. In Aspergillus flavus treatments, FAT significantly increased the content of methionine and threonine, whereas, aspartic acid showed 26 percentage decreases, compared to the control. Pronounced reductions in threonine, isoleucine and leucine were also detected in corn grains treated with BHA. Significant increases in fiber content were detected in inoculated corn grains treated with BHA, attaining 1.34 to 2.05-fold over that of control, respectively. Treatment with FAT and BHA led to pronounced reductions in moisture content in corn inoculated with both F. verticilloides and A. flavus trials. However, treatment with ground clove significantly increased the moisture content in A. flavus treatment. FAT treatment led to significant increase in ash and fat contents in both A. flavus and F. verticilloides treatments, whereas the other tested treatments of F. verticilloides significantly

  4. Effect of feeding peroxidized dried distillers grains with solubles to sows and progeny on growth performance and metabolic oxidative status of nursery pigs.

    Science.gov (United States)

    Hanson, A R; Wang, L; Johnston, L J; Baidoo, S K; Torrison, J L; Chen, C; Shurson, G C

    2015-01-01

    This experiment evaluated the effects of including peroxidized corn dried distillers grains with solubles (DDGS) in diets for sows and nursery pigs on growth performance, vitamin E (VE), and Se status, and the incidence of mulberry heart disease (MHD) of nursery pigs. Sows (n = 12) were fed corn-soybean meal diets (C-SBM) or C-SBM diets with DDGS (40% and 20% in gestation and lactation, respectively) for 3 parities. In the third parity, 108 weaned pigs (BW = 6.6 ± 0.36 kg) were blocked by BW within litter, assigned to pens (2 pigs/pen; 5 and 4 pens per litter for groups 1 and 2, respectively), and pens were assigned 1 of 3 nursery diets: 1) corn-soybean meal (CON), 2) 30% peroxidized DDGS (Ox-D), and 3) 30% Ox-D with 5 × NRC (1998) level of VE (Ox-D+5VE) for 7 wk, in a 2 × 3 factorial arrangement of sow and nursery diets (n = 9 pens/treatment). The peroxidized DDGS source in nursery diets contained concentrations of thiobarbituric acid reactive substances (TBARS) and peroxide values that were 25 and 27 times greater than a reference corn sample. Sow colostrum, milk, and serum, as well as pig serum and liver samples, were analyzed for α-tocopherol and Se concentrations. Pig serum was analyzed for glutathione peroxidase activity (GPx), TBARS, and sulfur-containing AA (SAA). Pig hearts were evaluated for gross and histopathological lesions indicative of MHD, but none were detected. Pigs from sows fed DDGS tended to have reduced (P = 0.07) VE in serum during lactation and reduced VE at weaning (P pigs from sows fed C-SBM. Inclusion of DDGS in sow diets reduced the VE status of pigs during lactation, but not in the nursery when MHD can be a concern. Pigs fed Ox-D+5VE (P = 0.08) tended to have, and those fed Ox-D (P = 0.04) had greater ADFI than pigs fed CON, but ADG was not affected (P > 0.1) by nursery diet. Feeding Ox-D or Ox-D+5VE increased (P pigs fed Ox-D or Ox-D+5VE compared with those fed C-SBM, which was likely due to greater (P pigs fed Ox-D. The

  5. Effects of late gestation distillers grains supplementation on fall-calving beef cow performance and steer calf growth and carcass characteristics.

    Science.gov (United States)

    Wilson, T B; Schroeder, A R; Ireland, F A; Faulkner, D B; Shike, D W

    2015-10-01

    Fall-calving, mature Angus and Simmental × Angus cows ( = 251 total) and their progeny were used to evaluate the effects of late gestation dried distillers grains plus solubles (DDGS) supplementation on cow performance and progeny growth and carcass characteristics. Cows were blocked by breed and allotted to 12 tall fescue pastures (6.8 ha average). Pastures were randomly assigned to 1 of 2 treatments: cows were offered 2.1 kg DM DDGS·cow·d (SUP; CP = 23%, fat = 7%; = 6 pastures) or were not offered a supplement (CON; = 6 pastures) 69 ± 9 d before expected calving date. Cows remained on treatments until calving. Once weekly, cows that had calved were removed from treatment pastures and were moved to new tall fescue pastures (21.6 ha average) where cows from both treatments were comingled without further supplementation. Cows ( = 74) were removed from study for calving more than 30 d after expected calving date, calf loss and injury, or euthanasia. Cow BW and BCS were recorded at the beginning of the supplementation period, after calving, and at breeding. Calf BW was taken at birth and early weaning (82 ± 14 d of age). After weaning, 71 steer progeny (representative of dam breed and treatment pastures) were transitioned to a common feedlot diet with individual feed intake monitored using the GrowSafe feeding system. Steers were slaughtered at 47 ± 4 d after a minimum 12th rib fat thickness (back fat) estimation of 0.6 cm, with cattle being shipped in 3 groups. Forage availability was not different between treatments ( = 0.69). Cows offered SUP gained more BW and BCS ( ≤ 0.02) during the supplementation period. There were no differences ( ≥ 0.12) in calving date, calf birth or weaning BW, or preweaning ADG. Cow BW at breeding was not different ( = 0.19); however, BCS at breeding was greater ( BCS but did not alter milk production, subsequent reproduction, or subsequent calf performance or carcass characteristics.

  6. Static Recrystallized Grain Size of Coarse-Grained Austenite in an API-X70 Pipeline Steel

    Science.gov (United States)

    Sha, Qingyun; Li, Guiyan; Li, Dahang

    2013-12-01

    The effects of initial grain size and strain on the static recrystallized grain size of coarse-grained austenite in an API-X70 steel microalloyed with Nb, V, and Ti were investigated using a Gleeble-3800 thermomechanical simulator. The results indicate that the static recrystallized grain size of coarse-grained austenite decreases with decreasing initial grain size and increasing applied strain. The addition of microalloying elements can lead to a smaller initial grain size for hot deformation due to the grain growth inhibition during reheating, resulting in decreasing of static recrystallized grain size. Based on the experimental data, an equation for the static recrystallized grain size was derived using the least square method. The grain sizes calculated using this equation fit well with the measured ones compared with the equations for fine-grained austenite and for coarse-grained austenite of Nb-V microalloyed steel.

  7. GRAIN GROWTH MODEL OF INCONEL 718 ALLOY FORGED SLAB IN REHEATING PROCESS PRIOR TO ROUGH ROLLING%Inconel 718合金方坯粗轧加热过程晶粒长大模型

    Institute of Scientific and Technical Information of China (English)

    陈礼清; 隋凤利; 刘相华

    2009-01-01

    The Inconel 718 superalloy is extensively used to manufacture critical parts in aero-nautical, astronautical, oil and chemical industries due to its excellent mechanical, physical and anti-corrosion behavior. Usually, these parts are shaped by hot forging or rolling in open-train mills. Recently, the tandem hot rolling has been applied to form superalloy bar products. In some cases, it can replace the traditional rolling, since it has higher productivity and product quality. In order to obtain the most favorable microstructure and the best mechanical properties of Inconel 718 alloy in tandem hot rolling, it is necessary to control its microstructural evolution in every step of the whole rolling process. With the aid of computer modeling, it is possible to make such a controlling process possible. As the first step in tandem hot rolling, reheating process of a forged slab prior to rough rolling plays a predominant role in predicting the grain size change or even the microstructural evo-lution. Thus, in this study, an Inconel 718 alloy forged slab was used as the experimental material and the effects of reheating temperature and holding time on its grain growth were investigated. A universal model was developed and verified for the grain growth of Inconel 718 alloy forged slab in reheating process prior to rough rolling. With the increase of holding time, the grain size shows no remarkable change up to 1173 K. The grain growth presents a linear trend in the range from 1173 to 1323 K. A parabolic trend of grain growth can be observed when reheating temperature is higher than 1323 K. The established grain growth model of Inconel 718 alloy would be suitable to calculate the grain size evolution under the both isothermal and non-isothermal reheating conditions. This could also provide a basis in formulating the technological parameters for tandem hot rolling of Inconel 718 superalloy.%以Inconel 718合金锻坯为研究对象,在1173-1423 K的温度范围内,研究

  8. [Abnormality in bone metabolism after burn].

    Science.gov (United States)

    Gong, X; Xie, W G

    2016-08-20

    Burn causes bone metabolic abnormality in most cases, including the changes in osteoblasts and osteoclasts, bone mass loss, and bone absorption, which results in decreased bone mineral density. These changes are sustainable for many years after burn and even cause growth retardation in burned children. The mechanisms of bone metabolic abnormality after burn include the increasing glucocorticoids due to stress response, a variety of cytokines and inflammatory medium due to inflammatory response, vitamin D deficiency, hypoparathyroidism, and bone loss due to long-term lying in bed. This article reviews the pathogenesis and regularity of bone metabolic abnormality after burn, the relationship between bone metabolic abnormality and burn area/depth, and the treatment of bone metabolic abnormality, etc. and discusses the research directions in the future. PMID:27562160

  9. 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.

  10. Interface Orientation Distribution during Grain Growth in Bulk SrTiO3 Measured by Means of 3D X-Ray Diffraction Contrast Tomography

    DEFF Research Database (Denmark)

    Syha, Melanie; Rheinheimer, Wolfgang; Bäurer, Michael;

    2012-01-01

    3D x-ray diffraction contrast tomography (DCT) is a non-destructive technique for the determination of grain shape and crystallography in polycrystalline bulk materials. Using this technique, a strontium titanate specimen was repeatedly measured between annealing steps.. A systematic analysis of ...... normal distribution clearly shows a preference for (100) oriented interfaces in the selected grains when annealed at 1600°C. This observation can be connected to existent interfacial energy estimations resulting from capillarity vector reconstructions. © 2012 Materials Research Society....

  11. Grain Structure Simulation of Magnesium Alloy Based on Corner Growth Algorithm%基于角点生长算法的镁合金晶粒组织模拟

    Institute of Scientific and Technical Information of China (English)

    宋迎德; 郝海; 张爱民; 李明; 张兴国

    2012-01-01

    A probabilistic method-cellular automata method with square cells, von Neumann neighborhood configuration for microstructure simulation of magnesium alloys was developed. During the solidification process, nucleation was controlled by the Gaussian distribution model; the crystallographic orientation was taken randomly; the growth kinetics of dendrite tips were obtained by solving KGT model and the relationship between undercooling and growth rate of dendrite tips was established with a third order polynomial; comer growth algorithm was proposed and applied to determine the capture and state transition of the cell. By using this new method, the growth of a single grain and more grains was simulated. The good agreement between experiments and simulation results of more grains shows the efficiency of this method.%建立了一种新的模型来模拟镁合金凝固组织,该模型采用了概率性元胞法(正方形元胞、四邻胞配置).凝固过程中的形核由高斯分布形核模型控制;枝晶的晶向随机定义;枝晶尖端的生长速度由KGT模型计算后拟合成三次多项式;元胞的捕捉和状态转换规则由针对镁合金密排六方特性设计的角点生长算法控制.利用该模型计算了单个及多个晶粒的生长过程,并通过多个晶粒模拟结果与实验结果的对比验证了模型的准确性.

  12. 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.

  13. 宁夏南山区籽粒苋根系生长特征研究%Study on Root System Growth Characteristics of Grain Amaranth in the South of Ningxia

    Institute of Scientific and Technical Information of China (English)

    杨俱和; 高继飞

    2012-01-01

    [Objective] The root system growth characteristics of grain amaranth were studied to provide the basis for management. [ Method] The root system growth characteristics of four species including ZL01, ZH01, K472 and ZH02 were observed and studied. [Result] The results showed that the root growth speed appeared rule of fast, slow, more faster and slower, which had a relationship between growth rule and root' s nutrient and the soil compactness. Ratio between root and shoot declined with growth period extend. [ Conclusion] Management must be strengthened to promote root growth when root of grain amaranth grow fastest.%[目的]研究籽粒苋的根系生长特征,为栽培管理提供依据.[方法]研究自繁绿苋ZL01、大田红苋黑籽ZH01、红苋K472、大田绿苋黑籽ZH024个籽粒苋品种的根系生长特性.[结果]籽粒苋根系长呈“先快、后慢、更快、再慢”的变化趋势,其变化特征与自身的营养条件和土壤紧实度有关,根冠比随着生育期的延长呈下降趋势.[结论]籽粒苋根系的生长最快时期应加强管理,以促进根系生长.

  14. 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.

  15. 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.……

  16. 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.

  17. Evolution of non-uniform grain structure during hot defornnation of a Nb-Ti microalloyed steel

    Directory of Open Access Journals (Sweden)

    Katajarinne, T.

    2004-10-01

    Full Text Available Recrystallisation and the evolution of the abnormally grown austenite grains were investigated for a continuously cast slab of a 0.13 C-1.41 Mn-0.027 Nb-0.012 Ti steel during reheating and after the subsequent deformation. The stability of the recrystallised structure and the uniformity of the final microstructure were also studied. The abnormally grown grains appear in a few minutes at reheating temperatures around 1200 °C. All grains in the bimodal grain structure recrystallised at 1100 °C for strains > 0.2 within about 40 s. The coarse grains are refined, while the fine grains become slightly larger. Some abnormal grain growth can occur again in the recrystallised structure within 10 min. After cooling at 1° C/s the coarse austenite grains transform into large areas of upper bainite, while the finer grains transform to fine ferrite and pearlite. The transformed microstructure in specimens cooled at l°C/s consists of large upper bainitic areas corresponding to the prior coarse austenite grains, surrounded by fine ferrite-pearlite grains.

    Se ha estudiado la recristalización y la evolución del crecimiento anormal de grano, durante el recalentamiento y tras deformaciones sucesivas, en un acero 0,13 C-1,41 Mn-0,027 Nb- 0,012 Ti procedente de colada continua. Se ha estudiado, así mismo, la estabilidad de la estructura recristalizada y la uniformidad de la microestructura final. Para temperaturas de recalentamiento próximas a 1.200 °C, aparece crecimiento anormal de grano en unos pocos minutos. Todos los granos pertenecientes a la estructura bimodal resultante recristalizan durante, aproximadamente, 40 s, a 1.100 °C, para una deformación de 0,2. El tamaño de grano se afina en aquellas regiones con granos más gruesos de partida y crece, ligeramente, en las que tenían un grano m��s fino. En 10 min, se puede desencadenar, de nuevo, un cierto crecimiento anormal de grano en la estructura recristalizada. La microestructura final

  18. Fractal dust grains in plasma

    Energy Technology Data Exchange (ETDEWEB)

    Huang, F. [College of Science, China Agricultural University, Beijing 100083 (China); Peng, R. D. [State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing 100083 (China); Liu, Y. H. [Institute of Complexity Science, Qingdao University, Qingdao 266071 (China); Chen, Z. Y. [Department of Physics, Beijing University of Chemical Technology, Beijing 100029 (China); Ye, M. F.; Wang, L. [Institute of Physics, Chinese Academy of Science, Beijing 100190 (China)

    2012-09-15

    Fractal dust grains of different shapes are observed in a radially confined magnetized radio frequency plasma. The fractal dimensions of the dust structures in two-dimensional (2D) horizontal dust layers are calculated, and their evolution in the dust growth process is investigated. It is found that as the dust grains grow the fractal dimension of the dust structure decreases. In addition, the fractal dimension of the center region is larger than that of the entire region in the 2D dust layer. In the initial growth stage, the small dust particulates at a high number density in a 2D layer tend to fill space as a normal surface with fractal dimension D = 2. The mechanism of the formation of fractal dust grains is discussed.

  19. Chromosomal Abnormalities in ADHD

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2002-07-01

    Full Text Available The prevalence of fragile X syndrome, velocardiofacial syndrome (VCFS, and other cytogenetic abnormalities among 100 children (64 boys with combined type ADHD and normal intelligence was assessed at the NIMH and Georgetown University Medical Center.

  20. Chromosomal abnormalities and autism

    Directory of Open Access Journals (Sweden)

    Farida El-Baz

    2016-01-01

    Conclusion: Chromosomal abnormalities were not detected in the studied autistic children, and so the relation between the genetics and autism still needs further work up with different study methods and techniques.

  1. Abnormal protein aggregationand neurodegenerativediseases

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Abnormal protein aggregation or amyloid is the major cause ofmany neurodegenerative disorders. The present review focuses on the correlation between sequence and structure features of proteins related to the diseases and abnormal protein aggregation. Recent progress has improved our knowledge on understand-ing the mechanism of amyloid formation. We suggest a nucleation model for ordered protein aggregation, which can also explain pathogenesis mechanisms of these neurodegenerative diseases in vivo.

  2. Sintering and grain growth kinetics in La0.85Sr0.15MnO3–Ce0.9Gd0.1O1.95 (LSM–CGO) porous composite

    DEFF Research Database (Denmark)

    Ni, De Wei; Andersen, Kjeld Bøhm; Esposito, Vincenzo

    2014-01-01

    The sintering kinetics in La0.85Sr0.15MnO3–Ce0.9Gd0.1O1.95 (LSM–CGO) porous composite was studied by applying a two-stage master sintering curve (MSC) approach and comparing with LSM and CGO single-phase materials. In the two-stage MSC, sintering mechanisms occurring at different stages were...... of the composite. Similarly, constrain effect was also observed in grain growth in the composite. Particularly, in the investigated temperature range (1100–1250°C), the determined grain boundary mobility of CGO in the LSM–CGO composite (10−18–10−16m3N−1s−1) is comparable with the single-phase CGO, while the grain...... boundary mobility of LSM in the composite (10−17–10−16m3N−1s−1) is around 1 order of magnitude smaller than the single-phase LSM....

  3. Large grain growth of Ge-rich Ge{sub 1−x}Sn{sub x} (x ≈ 0.02) on insulating surfaces using pulsed laser annealing in flowing water

    Energy Technology Data Exchange (ETDEWEB)

    Kurosawa, Masashi, E-mail: kurosawa@alice.xtal.nagoya-u.ac.jp [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); JSPS, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083 (Japan); Taoka, Noriyuki; Nakatsuka, Osamu; Zaima, Shigeaki [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Ikenoue, Hiroshi [Graduate School of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan)

    2014-02-10

    We investigate Sn incorporation effects on the growth characteristics of Ge-rich Ge{sub 1−x}Sn{sub x} (x < 0.02) on SiO{sub 2} crystallized by pulsed laser annealing (PLA) in air and water. Despite the very low Sn content of 2%, Sn atoms within the GeSn layers play a role in preventing ablation and aggregation of the layers during these PLA. Raman and electron backscatter diffraction measurements demonstrate achievement of large-grain (∼800 nmϕ) growth of Ge{sub 0.98}Sn{sub 0.02} polycrystals by using PLA in water. These polycrystals also show a tensile-strain of ∼0.68%. This result opens up the possibility for developing GeSn-based devices fabricated on flexible substrates as well as Si platforms.

  4. Grain amaranths are defoliation tolerant crop species capable of utilizing stem and root carbohydrate reserves to sustain vegetative and reproductive growth after leaf loss.

    Directory of Open Access Journals (Sweden)

    Erandi Vargas-Ortiz

    Full Text Available Tolerance to defoliation can be defined as the degree to which productivity is affected by photosynthetic area reduction. This trait was studied in grain amaranth (Amaranthus cruentus and A. hypochondriacus, which are considered to be a highly defoliation-tolerant species. The physiological and biochemical responses to increasing levels of mechanical leaf removal up to total defoliation were quantified. Tolerance appeared to be dependent on various factors: ( i amount of lost tissue; (ii mechanics of leaf tissue removal; (iii environment, and (iv species tested. Thus, grain amaranth was found to be a highly tolerant species under green-house conditions when leaf tissue loss was performed by gradual perforation. However, tolerance was compromised under similar conditions when defoliation was done by gradual cutting of the leaf. Also tolerance in completely defoliated plants tended to decrease under field conditions, where differences between A. cruentus and A. hypochondriacus were observed. All non-structural carbohydrate (NSC levels were reduced in stems and roots of totally defoliated amaranths one day after treatment. Such depletion probably provided the carbon (C resources needed to sustain the early recovery process in the absence of photosynthetic capacity. This was corroborated by shading of intact plants, which produced the same rapid and drastic reduction of NSC levels in these tissues. These results emphasize the role of stored NSCs, particularly starch, in buffering the impact of severe defoliation in amaranth. The fall in sucrose synthase and cell wall invertase activity observed in stems and roots soon after defoliation was consistent with their predicted shift from sink to source tissues. It is concluded that mobilization of C stores in stems and roots, is a physiologically important trait underlying tolerance to defoliation in grain amaranth.

  5. Fabrication of single-grain GdBa2Cu3O7− bulk superconductors with a new kind of liquid source by the top seeded infiltration and growth technique

    Indian Academy of Sciences (India)

    Guo-Zheng Li; Wan-Min Yang; Xiao-Fang Cheng; Jing Fan; Xiao-Dan Guo

    2010-05-01

    Compared to the conventional melt growth (MG) method, the top seeded infiltration and growth (TSIG) process is an effective way for preparing bulk REBa2Cu3O7− (RE-123) with finely dispersed RE2BaCuO5 (RE-211) particles. However, it is more complicated and time-consuming, because three kinds of precursor powders, namely, RE-211, RE-123 and BaCuO2, have to be prepared for the conventional TSIG process. In this paper, a new liquid source (NLS) composed of RE-211 and Ba3Cu5O8, was proposed for simplifying the TSIG process, which is different from the regular liquid source (RLS) composed of RE-123 and Ba3Cu5O8. In this modified TSIG technique, we need to prepare only RE-211 and BaCuO2 powders. Single-grain GdBa2Cu3O7− (GdBCO) bulk super-conductors have been fabricated using the RLS and NLS separately. The morphology, microstructure and levitation force of the bulk GdBCO have also been investigated. The results indicate that the NLS can be used to simplify the process flow and improve the efficiency on the fabrication of single-grain GdBCO superconductors.

  6. Growth performance, behaviour, forestomach development and meat quality of veal calves provided with barley grain or ground wheat straw for welfare purpose

    Directory of Open Access Journals (Sweden)

    Igino Andrighetto

    2010-01-01

    Full Text Available Two different feeding plans for veal calves were compared in the study: a traditional liquid diet supplemented with 250  g/calf/d of barley grain or with 250 g/calf/d of ground wheat straw. The two solid feeds had different chemical composi-  tion but a similar particle size obtained by grinding the straw in a mill with an 8-mm mesh screen. Twenty-four Polish  Friesian male calves were used in the study and they were housed in individual wooden stalls (0.83 x 1.80 m. The health  status of all the calves was satisfactory for the entire fattening period and no specific medical treatment was required  during the trial. Calves fed wheat straw showed a greater intake of solid feed (196 vs. 139 g/d; P  average daily gain (1288 vs. 1203 g/d; P  not affected by the type of solid feed and no milk refusal episodes were detected. The haemoglobin concentration was  similar in calves receiving the two feeding treatments despite the higher iron intake provided by the wheat straw through-  out the fattening period (2.12 vs. 1.15 g; P  calves’ metabolism. Feeding behaviour was affected by the provision of solid feeds. Eating and chewing were prolonged  in calves receiving ground wheat straw and the same solid feed reduced the frequency of oral stereotypies at the end of  the fattening period. At the slaughterhouse, no differences were observed between the feeding treatments as regards  carcass weight and dressing percentage. The calves fed ground wheat straw had a heavier weight of the empty omasum  (518 vs. 341 g; P  fed barley grain. The incidence of abomasal erosions, ulcers and scars was similar in both treatments; however the index  of abomasal damage, which considers the number and the seriousness of different type of lesions, was higher in calves  receiving barley grain. Therefore, the grinding of straw particles, as opposed to barley grain, can reduce the abrasive-  ness of roughage at the abomasum level. Visual evaluation of the

  7. [Hair shaft abnormalities].

    Science.gov (United States)

    Itin, P H; Düggelin, M

    2002-05-01

    Hair shaft disorders may lead to brittleness and uncombable hair. In general the hair feels dry and lusterless. Hair shaft abnormalities may occur as localized or generalized disorders. Genetic predisposition or exogenous factors are able to produce and maintain hair shaft abnormalities. In addition to an extensive history and physical examination the most important diagnostic examination to analyze a hair shaft problem is light microscopy. Therapy of hair shaft disorders should focus to the cause. In addition, minimizing traumatic influences to hair shafts, such as dry hair with an electric dryer, permanent waves and dyes is important. A short hair style is more suitable for such patients with hair shaft disorders.

  8. Neurological abnormalities predict disability

    DEFF Research Database (Denmark)

    Poggesi, Anna; Gouw, Alida; van der Flier, Wiesje;

    2014-01-01

    was performed. MRI assessment included age-related white matter changes (ARWMC) grading (mild, moderate, severe according to the Fazekas' scale), count of lacunar and non-lacunar infarcts, and global atrophy rating. Of the 633 (out of the 639 enrolled) patients with follow-up information (mean age 74.1 ± 5......, presence and number of neurological examination abnormalities predicted global functional decline independent of MRI lesions typical of the aging brain and other determinants of disability in the elderly. Systematically checking for neurological examination abnormalities in older patients may be cost...

  9. 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.

  10. Predicting gas in place in abnormal reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Stelly, O.V. II; Farshad, F.F.

    1981-06-01

    Application of the conventional gas material balance equation to abnormally pressured volumetric reservoirs results in erroneous estimates of ultimate recovery. In view of the increasing number and importance of this type of reservoir, the program presented results in more realistic predictions. In abnormally pressured reservoirs, the formation is not supporting as great a portion of the overburden stress. Thus, when pressure is depleted, the sand grains and connate water of the formation expand. These factors tend to reduce the available hydrocarbon pore space acting as a drive mechanism. Thus, production is due to a combination of factors that cause subsequent changes in effective compressibility of the formation rather than just gas compressibility. Hammelindl proposed a correction factor equivalent to the ratio of effective compressibility to gas compressibility. This is applied to the results obtained for normally pressured reservoirs.

  11. Comparative proteomic analysis provides new insights into cadmium accumulation in rice grain under cadmium stress

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Dawei, E-mail: dwxue@hznu.edu.cn [College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036 (China); State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006 (China); Jiang, Hua [State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Science, Hangzhou 310021 (China); Deng, Xiangxiong; Zhang, Xiaoqin [College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036 (China); Wang, Hua [State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Science, Hangzhou 310021 (China); Xu, Xiangbin [College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036 (China); Hu, Jiang; Zeng, Dali [State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006 (China); Guo, Longbiao, E-mail: guolongbiao@caas.cn [State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006 (China); Qian, Qian, E-mail: qianqian188@hotmail.com [College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036 (China); State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006 (China)

    2014-09-15

    Graphical abstract: - Highlights: • Cd is the most toxic heavy metal and is a major pollutant in rice grains. • The mechanism of Cd accumulation in rice grains has not been well demonstrated. • Proteomics analysis is carried out and the verification is implemented by QPCR. • Proteins associated with ROS and photosynthesis showed large variation in expression. - Abstract: Rice is one of the most important staple crops. During the growth season, rice plants are inevitably subjected to numerous stresses, among which heavy metal stress represented by cadmium contamination not only hindering the yield of rice but also affecting the food safety by Cd accumulating in rice grains. The mechanism of Cd accumulation in rice grains has not been well elucidated. In this study, we compare the proteomic difference between two genotypes with different Cd accumulation ability in grains. Verification of differentially expressed protein-encoding genes was analyzing by quantitative PCR (QPCR) and reanalysis of microarray expression data. Forty-seven proteins in total were successfully identified through proteomic screening. GO and KEGG enrichment analysis showed Cd accumulation triggered stress-related pathways in the cells, and strongly affecting metabolic pathways. Many proteins associated with nutrient reservoir and starch-related enzyme were identified in this study suggesting that a considerably damage on grain quality was caused. The results also implied stress response was initiated by the abnormal cells and the transmission of signals may mediated by reactive oxygen species (ROS). Our research will provide new insights into Cd accumulation in rice grain under Cd stress.

  12. Chromosomal phenotypes and submicroscopic abnormalities

    Directory of Open Access Journals (Sweden)

    Devriendt Koen

    2004-01-01

    Full Text Available Abstract The finding, during the last decade, that several common, clinically delineated syndromes are caused by submicroscopic deletions or, more rarely, by duplications, has provided a powerful tool in the annotation of the human genome. Since most microdeletion/microduplication syndromes are defined by a common deleted/duplicated region, abnormal dosage of genes located within these regions can explain the phenotypic similarities among individuals with a specific syndrome. As such, they provide a unique resource towards the genetic dissection of complex phenotypes such as congenital heart defects, mental and growth retardation and abnormal behaviour. In addition, the study of phenotypic differences in individuals with the same microdeletion syndrome may also become a treasury for the identification of modifying factors for complex phenotypes. The molecular analysis of these chromosomal anomalies has led to a growing understanding of their mechanisms of origin. Novel tools to uncover additional submicroscopic chromosomal anomalies at a higher resolution and higher speed, as well as the novel tools at hand for deciphering the modifying factors and epistatic interactors, are 'on the doorstep' and will, besides their obvious diagnostic role, play a pivotal role in the genetic dissection of complex phenotypes.

  13. 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.

  14. Abnormal austenite-ferrite transformation behavior in pure iron

    Institute of Scientific and Technical Information of China (English)

    LIU Yongchang; F.Sommer; E.J. Mittemeijer

    2004-01-01

    The austenite → ferrite transformation is the most important reaction route in the manufacture of Fe-based materials. Here the austenite (γ) → ferrite (α)transformation of pure iron was systematically explored by high-resolution dilatometry. Abnormal transformation kinetics, multi-peak discontinuous reaction, was recognized in pure iron according to the variation of the ferrite-formation rate. The occurrence the one or the other type of γ→α trans formation strongly depends on the grain size: the transformation type changes from abnormal to normal (single-peak continuous reaction) with decreasing grain size. The inherent reason for the occurrence of abnormal transformation could be attributed to the repeated nucleation in front of the moving γ/α interface induced by the accumulation of elastic and plastic accommodation energy.

  15. 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.

  16. Abnormal ionization in sonoluminescence

    Institute of Scientific and Technical Information of China (English)

    张文娟; 安宇

    2015-01-01

    Sonoluminescence is a complex phenomenon, the mechanism of which remains unclear. The present study reveals that an abnormal ionization process is likely to be present in the sonoluminescing bubble. To fit the experimental data of previous studies, we assume that the ionization energies of the molecules and atoms in the bubble decrease as the gas density increases and that the decrease of the ionization energy reaches about 60%–70%as the bubble flashes, which is difficult to explain by using previous models.

  17. Ultrasonography of splenic abnormalities

    Institute of Scientific and Technical Information of China (English)

    Ming-Jen Chen; Ming-Jer Huang; Wen-Hsiung Chang; Tsang-En Wang; Horng-Yuan Wang; Cheng-Hsin Chu; Shee-Chan Lin; Shou-Chuan Shih

    2005-01-01

    AIM: This report gives a comprehensive overview of ultrasonography of splenic abnormalities. Certain ultrasonic features are also discussed with pathologic correlation.METHODS: We review the typical ultrasonic characteristics of a wide range of splenic lesions, illustrating them with images obtained in our institution from 2000 to 2003.One hundred and three patients (47 men, 56 women),with a mean age of 54 years (range 9-92 years), were found to have an abnormal ultrasonic pattern of spleen.RESULTS: We describe the ultrasonic features of various splenic lesions such as accessory spleen, splenomegaly,cysts, cavernous hemangiomas, lymphomas, abscesses,metastatic tumors, splenic infarctions, hematomas, and rupture, based on traditional gray-scale and color Doppler sonography.CONCLUSION: Ultrasound is a widely available, noninvasive,and useful means of diagnosing splenic abnormalities. A combination of ultrasonic characteristics and clinical data may provide an accurate diagnosis. If the US appearance alone is not enough, US may also be used to guide biopsy of suspicious lesions.

  18. Comparative effect of salinity on growth, grain yield, water use efficiency, δ(13)C and δ(15)N of landraces and improved durum wheat varieties.

    Science.gov (United States)

    Chamekh, Zoubeir; Ayadi, Sawsen; Karmous, Chahine; Trifa, Youssef; Amara, Hajer; Boudabbous, Khaoula; Yousfi, Salima; Serret, Maria Dolors; Araus, José Luis

    2016-10-01

    Supplemental irrigation with low-quality water will be paramount in Mediterranean agriculture in the future, where durum wheat is a major crop. Breeding for salinity tolerance may contribute towards improving resilience to irrigation with brackish water. However, identification of appropriate phenotyping traits remains a bottleneck in breeding. A set of 25 genotypes, including 19 landraces and 6 improved varieties most cultivated in Tunisia, were grown in the field and irrigated with brackish water (6, 13 and 18dSm(-1)). Improved genotypes exhibited higher grain yield (GY) and water use efficiency at the crop level (WUEyield or 'water productivity'), shorter days to flowering (DTF), lower N concentration (N) and carbon isotope composition (δ(13)C) in mature kernels and lower nitrogen isotope composition (δ(15)N) in the flag leaf compared with landraces. GY was negatively correlated with DTF and the δ(13)C and N of mature kernels and was positively correlated with the δ(15)N of the flag leaf. Moreover, δ(13)C of mature kernels was negatively correlated with WUEyield. The results highlight the importance of shorter phenology together with photosynthetic resilience to salt-induced water stress (lower δ(13)C) and nitrogen metabolism (higher N and δ(15)N) for assessing genotypic performance to salinity. PMID:27593462

  19. Micromechanical testing of stress corrosion cracking of individual grain boundaries

    International Nuclear Information System (INIS)

    Grain boundaries of different misorientation and chemistry have differing susceptibilities to stress corrosion cracking but carrying out mechanical tests on individual grain boundaries of known character has until now been very difficult. We present a method for manufacturing specimens containing a single grain boundary (in 304 stainless steel) using focused ion beam machining. A nanoindenter/atomic force microscope was used to drive controlled grain boundary crack growth under load in an active solution. Scanning electron microscopy examination confirmed the growth of the crack along the grain boundary.

  20. 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.

  1. 大晶粒多晶硅铸锭生长的热场设计与模拟%Thermal System Design and Simulation for Growth of Large Grain Multi-crystal Silicon Ingot

    Institute of Scientific and Technical Information of China (English)

    娄中士; 左然; 苏文佳; 杨琳

    2011-01-01

    为了生长大晶粒的多晶硅铸锭,晶体从形核到后续生长的热场环境控制至关重要.本文首先在侧加热器与散热块之间加一可移动的隔热环.通过向上移动隔热环,并在底部喷射氩气冷却,对生长工艺进行优化控制.然后利用数值模拟,对改进后的生长界面形状、晶体和熔体中的等温线、晶体和熔体的轴向温度分布以及冷却量对生长环境的影响进行分析.模拟结果表明:冷却速率的最佳值在5 ~ 15 W/m2之间,且优化后的晶体和熔体中等温线更平坦,晶体轴向温度梯度增大约1.72 K/cm,从而可有效地避免侧壁形核,促进大晶粒的生长,同时提高了生长速率.%In order to grow large grain multi-crystalline silicon in DSS silicon casting, the key process is to control the thermal system for bulk growth. In this study a moving partition block between the side heater and the heat exchanger block is added. By lifting the partition block and adding a jet cooling on the bottom block, casting process is controlled optimally. Through the numerical simulation, effects of different cooling flux on growth environment are discussed, and then growth interface, isotherm in the melt and crystal, axial temperature distribution in melt and in crystal are modeled. The results indicate; the optimal value of cooling flux is between 5 W/m2 and 15 W/m2; for the new design, the isotherms in the melt and crystal become more flat, and the axial temperature gradient in crystal increases about 1.72 K/cm, which are helpful for avoiding nucleation on the crucible wall, obtaining large grain multi-crystal, and also increasing the growth rate.

  2. PRESENT STATE AND PROBLEMS OF FORMING AN EFFECTIVE GRAIN MARKET

    OpenAIRE

    Tsvyrko, A.

    2012-01-01

    The article deals with current issues of forming a highly grain market. Statistical data reflecting the current state of the problem. Based on studies of the current state of the grain market highlighted the main target indicators defined the conditions for achieving the projected performance of the grain market and its products and recommendations for further development and growth of grain production capacity in Russia.

  3. Foreign Grain Security Mechanisms and Implications for China

    OpenAIRE

    Cao, Shuhua; Nie, Lei; Ma, Weipeng

    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 na...

  4. Marketing Farm Grain Crops.

    Science.gov (United States)

    Ridenour, Harlan E.

    This vocational agriculture curriculum on grain marketing contains three parts: teacher guide, student manual, and student workbook. All three are coordinated and cross-referenced. The course is designed to give students of grain marketing a thorough background in the subject and provide practical help in developing grain marketing strategies for…

  5. Growth Status, Grain Yield and Heavy Metals Content of Rice(Oryza sativa L.) as Affected by Biogas Slurry Application%沼液对水稻生长产量及其重金属含量的影响

    Institute of Scientific and Technical Information of China (English)

    张进; 张妙仙; 单胜道; 骆林平; 王敏艳

    2009-01-01

    Biogas slurry, in agriculture, is a typical high-quality organic material. At present in China, two hundred million tons of biogas slur-ry is producing per year. So, the secondary use of biogas slurry in agriculture production is to avoid environmental pollution and to achieve the ecological sustainable development for the livestock and poultry industries, is of great practical significance and the social meanings. So the effects of biogas slurry and chemical fertilizer application on plant growth, grain yield and heavy metals content in rice seeds of the japonica 'No.1 Ya You Hong' were studied with series of field trials. The results showed that a highest rice grain yield(55.9 g·plant~(-1)) was obtained with the application of biogas slurry as basal fertilizer and the compound K_2SO_4 fertilizer(N:P_2O_5:K_2O=15:15:15) as supplemental fertilizer. The cost of rice production was obviously low for biogas slurry as basal fertilizer though no significant grain yield improvement was observed in compare to the customarily local fertilization in which both the basal and supplemental fertilizers were K_2SO_4 compound fertilizers. Meanwhile, that biogas slurry as basal fertilizer and the compound fertilizer as supplemental fertilizer could increase markedly rice plant tillers and growth, and could enhance Fe and Zn contents and reduce significantly Pb content in rice seeds, although no significant changes in Cu and Cd contents in rice seeds were obtained. Uncertainly, the experiment results also showed that only biogas slurry application on rice production could not meet the nutrition demand for rice plant growth as well as grain yield.%沼气发酵残余液(沼液)是一种典型的优质有机物料,目前我国每年产生2亿多吨的沼液,农业生产中寻求沼液的资源化利用,对避免环境二次污染和实现畜禽养殖业的生态可持续发展具有重大的现实意义和社会意义.在田间小区试验条件

  6. Abnormal ionization in sonoluminescence

    Science.gov (United States)

    Zhang, Wen-Juan; An, Yu

    2015-04-01

    Sonoluminescence is a complex phenomenon, the mechanism of which remains unclear. The present study reveals that an abnormal ionization process is likely to be present in the sonoluminescing bubble. To fit the experimental data of previous studies, we assume that the ionization energies of the molecules and atoms in the bubble decrease as the gas density increases and that the decrease of the ionization energy reaches about 60%-70% as the bubble flashes, which is difficult to explain by using previous models. Project supported by the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20120002110031) and the National Natural Science Foundation of China (Grant No. 11334005).

  7. 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

  8. 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

  9. Interstellar grains in elliptical galaxies grain evolution

    CERN Document Server

    Tsai, J C; Tsai, John C; Mathews, William G

    1995-01-01

    We consider the lifecycle of dust introduced into the hot interstellar medium in isolated elliptical galaxies. Dust grains are ejected into galactic-scale cooling flows in large ellipticals by normal mass loss from evolving red giants. Newly introduced dust rapidly enters the hot gas environment and is sputtered away by thermal collisions with ions. Before the grains are completely sputtered away, they emit prodigious amounts of infrared radiation which may contribute to the large far infrared luminosities observed in ellipticals. In order to study the global properties of grains in ellipticals we construct a new series of King-type galactic models which are consistent with the fundamental plane, galactic mass to light ratios and other relevant observational correlations. We describe a new ``continuity'' procedure to construct simple time-dependent gas dynamic models for cooling flows. In all galaxy models, although grains can flow a considerable distance from their radius of origin before being sputtered awa...

  10. Manganese Abnormity in Holocene Sediments of the Bohai Sea

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Manganese abnormity has been observed in the Holocene sediments of the mud area of Bohai Sea. On the basis of grain size, chemical composition, heavy mineral content and accelerator mass spectrometry (AMS) 14C dating of foraminifer, relationships between manganese abnormity and sedimentation rates, material source, hydrodynamic conditions are probed. Manganese abnormity occurred during the Middle Holocene when sea level and sedimentation rates were higher than those at present. Sedimentary hiatus was not observed when material sources and hydrodynamic conditions were quite similar. Compared with the former period, the latter period showed a decrease in reduction environment and an inclination toward oxidation environment with high manganese content, whereas provenance and hydrodynamic conditions showed only a slight change. From the above observations, it can be concluded that correlation among manganese abnormity, material source, and hydrodynamic conditions is not obvious. Redox environment seems to be the key factor for manganese enrichment, which is mainly related to marine authigenic process.

  11. The effect of S-(ferrocenylmethyl-thiosalicylic acid sodium salt on the germination and growth of cereal grains and seedlings and on the development of pathogenic fungi

    Directory of Open Access Journals (Sweden)

    Jan Michalczyk

    2014-02-01

    Full Text Available The sodium salt of S-(ferrocenylmethyl-thiosalicylic acid was studied in the context of its possible use as a systemic fungicide and, concurrently, as a source of physiologically active iron fur crop plants. It was found that this metallocene was taken up by maize seedlings growing in liquid mediums, and used for chlorophyll synthesis, in a concentration range as low as 0.05-0.08 mM dm-3. In the concentration range of 0.05-1.5 mM dm-3, it inhibited germination, seedling growth and Y-amylase activity while it stimulated the activities of proteinases, catalase and peroxidase. When sprayed on cereal leaves at a concentration of 1.0-2.0 mM dm-3, it exhibited fungicidal properties: inhibition of fungus development without harming cereal plant leaves and stimulated chlorophyll synthesis.

  12. Abnormal Austenite-Ferrite Transformation Behaviors of Fe-Si:Dilatometric Measurements

    Institute of Scientific and Technical Information of China (English)

    LIU Yong-chang; ZHANG Zhe-ping; ZHAO Kai; LI Bao-yin

    2004-01-01

    The isochronal γ→α transformation of Fe-1Si alloy was measured by high-resolution dilatometry. According to the variation of the ferrite formation rate, an abnormal γ→α phase transformation was recognized, while normal reaction,i.e. one peak continuous reaction, was also detected. The occurrence the one or the other type of γ→α transformation strongly depends on the grain size: the transformation type changes from abnormal to normal with decreasing grain size. In the abnormal transformation process the first stage of the transformation corresponds to the first peaks in the transformation rate, which are not thermally activated.

  13. A Rare Stapes Abnormality

    Directory of Open Access Journals (Sweden)

    Hala Kanona

    2015-01-01

    Full Text Available The aim of this study is to increase awareness of rare presentations, diagnostic difficulties alongside management of conductive hearing loss and ossicular abnormalities. We report the case of a 13-year-old female reporting progressive left-sided hearing loss and high resolution computed tomography was initially reported as normal. Exploratory tympanotomy revealed an absent stapedius tendon and lack of connection between the stapes superstructure and footplate. The footplate was fixed. Stapedotomy and stapes prosthesis insertion resulted in closure of the air-bone gap by 50 dB. A review of world literature was performed using MedLine. Middle ear ossicular discontinuity can result in significant conductive hearing loss. This can be managed effectively with surgery to help restore hearing. However, some patients may not be suitable or decline surgical intervention and can be managed safely conservatively.

  14. Growth

    Science.gov (United States)

    Waag, Andreas

    This chapter is devoted to the growth of ZnO. It starts with various techniques to grow bulk samples and presents in some detail the growth of epitaxial layers by metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), and pulsed laser deposition (PLD). The last section is devoted to the growth of nanorods. Some properties of the resulting samples are also presented. If a comparison between GaN and ZnO is made, very often the huge variety of different growth techniques available to fabricate ZnO is said to be an advantage of this material system. Indeed, growth techniques range from low cost wet chemical growth at almost room temperature to high quality MOCVD growth at temperatures above 1, 000∘C. In most cases, there is a very strong tendency of c-axis oriented growth, with a much higher growth rate in c-direction as compared to other crystal directions. This often leads to columnar structures, even at relatively low temperatures. However, it is, in general, not straight forward to fabricate smooth ZnO thin films with flat surfaces. Another advantage of a potential ZnO technology is said to be the possibility to grow thin films homoepitaxially on ZnO substrates. ZnO substrates are mostly fabricated by vapor phase transport (VPT) or hydrothermal growth. These techniques are enabling high volume manufacturing at reasonable cost, at least in principle. The availability of homoepitaxial substrates should be beneficial to the development of ZnO technology and devices and is in contrast to the situation of GaN. However, even though a number of companies are developing ZnO substrates, only recently good quality substrates have been demonstrated. However, these substrates are not yet widely available. Still, the situation concerning ZnO substrates seems to be far from low-cost, high-volume production. The fabrication of dense, single crystal thin films is, in general, surprisingly difficult, even when ZnO is grown on a ZnO substrate. However

  15. 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.

  16. Grain Refinement of Deoxidized Copper

    Science.gov (United States)

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

    2016-08-01

    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.

  17. 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.

  18. Abnormal uterine bleeding.

    Science.gov (United States)

    Whitaker, Lucy; Critchley, Hilary O D

    2016-07-01

    Abnormal uterine bleeding (AUB) is a common and debilitating condition with high direct and indirect costs. AUB frequently co-exists with fibroids, but the relationship between the two remains incompletely understood and in many women the identification of fibroids may be incidental to a menstrual bleeding complaint. A structured approach for establishing the cause using the Fédération International de Gynécologie et d'Obstétrique (FIGO) PALM-COEIN (Polyp, Adenomyosis, Leiomyoma, Malignancy (and hyperplasia), Coagulopathy, Ovulatory disorders, Endometrial, Iatrogenic and Not otherwise classified) classification system will facilitate accurate diagnosis and inform treatment options. Office hysteroscopy and increasing sophisticated imaging will assist provision of robust evidence for the underlying cause. Increased availability of medical options has expanded the choice for women and many will no longer need to recourse to potentially complicated surgery. Treatment must remain individualised and encompass the impact of pressure symptoms, desire for retention of fertility and contraceptive needs, as well as address the management of AUB in order to achieve improved quality of life. PMID:26803558

  19. Ictal Cardiac Ryhthym Abnormalities.

    Science.gov (United States)

    Ali, Rushna

    2016-01-01

    Cardiac rhythm abnormalities in the context of epilepsy are a well-known phenomenon. However, they are under-recognized and often missed. The pathophysiology of these events is unclear. Bradycardia and asystole are preceded by seizure onset suggesting ictal propagation into the cortex impacting cardiac autonomic function, and the insula and amygdala being possible culprits. Sudden unexpected death in epilepsy (SUDEP) refers to the unanticipated death of a patient with epilepsy not related to status epilepticus, trauma, drowning, or suicide. Frequent refractory generalized tonic-clonic seizures, anti-epileptic polytherapy, and prolonged duration of epilepsy are some of the commonly identified risk factors for SUDEP. However, the most consistent risk factor out of these is an increased frequency of generalized tonic-clonic seizures (GTC). Prevention of SUDEP is extremely important in patients with chronic, generalized epilepsy. Since increased frequency of GTCS is the most consistently reported risk factor for SUDEP, effective seizure control is the most important preventive strategy. PMID:27347227

  20. Communication and abnormal behaviour.

    Science.gov (United States)

    Crown, S

    1979-01-01

    In this paper the similarities between normal and abnormal behaviour are emphasized and selected aspects of communication, normal and aberrant, between persons are explored. Communication in a social system may be verbal or non-verbal: one person's actions cause a response in another person. This response may be cognitive, behavioural or physiological. Communication may be approached through the individual, the social situation or social interaction. Psychoanalysis approaches the individual in terms of the coded communications of psychoneurotic symptoms or psychotic behaviour; the humanist-existential approach is concerned more with emotional expression. Both approaches emphasize the development of individual identity. The interaction between persons and their social background is stressed. Relevant are sociological concepts such as illness behaviour, stigma, labelling, institutionalization and compliance. Two approaches to social interactions are considered: the gamesplaying metaphor, e.g. back pain as a psychosocial manipulation--the 'pain game'; and the 'spiral of reciprocal perspectives' which emphasizes the interactional complexities of social perceptions. Communicatory aspects of psychological treatments are noted: learning a particular metaphor such as 'resolution' of the problem (psychotherapy), learning more 'rewarding' behaviour (learning theory) or learning authenticity or self-actualization (humanist-existential).

  1. Communication and abnormal behaviour.

    Science.gov (United States)

    Crown, S

    1979-01-01

    In this paper the similarities between normal and abnormal behaviour are emphasized and selected aspects of communication, normal and aberrant, between persons are explored. Communication in a social system may be verbal or non-verbal: one person's actions cause a response in another person. This response may be cognitive, behavioural or physiological. Communication may be approached through the individual, the social situation or social interaction. Psychoanalysis approaches the individual in terms of the coded communications of psychoneurotic symptoms or psychotic behaviour; the humanist-existential approach is concerned more with emotional expression. Both approaches emphasize the development of individual identity. The interaction between persons and their social background is stressed. Relevant are sociological concepts such as illness behaviour, stigma, labelling, institutionalization and compliance. Two approaches to social interactions are considered: the gamesplaying metaphor, e.g. back pain as a psychosocial manipulation--the 'pain game'; and the 'spiral of reciprocal perspectives' which emphasizes the interactional complexities of social perceptions. Communicatory aspects of psychological treatments are noted: learning a particular metaphor such as 'resolution' of the problem (psychotherapy), learning more 'rewarding' behaviour (learning theory) or learning authenticity or self-actualization (humanist-existential). PMID:261653

  2. Stability of the grain structure in 2219-O aluminum alloy friction stir welds during solution treatment

    International Nuclear Information System (INIS)

    The stability of the grain structure in 2219-O aluminum alloy friction stir welds during solution treatment has been investigated. Experimental results show that the solution treatment causes drastic grain growth, Grain growth initiates at the surface and the bottom of the weld and then extends to the weld centre within several minutes. The solution treatment temperature and the welding heat input have a significant effect on grain growth. The higher the solution temperature, or the higher the welding heat input, the greater the grain growth. The instability of the grains is attributed to an imbalance between thermodynamic driving forces for grain growth and the pinning forces impeding grain boundary migration during solution treatment

  3. Comparative feeding value of distillers dried grains plus solubles as a partial replacement for steam-flaked corn in diets for calf-fed Holstein steers: characteristics of digestion, growth performance, and dietary energetics.

    Science.gov (United States)

    Carrasco, R; Arrizon, A A; Plascencia, A; Torrentera, N G; Zinn, R A

    2013-04-01

    Two experiments were conducted to examine the effect of level of dried distillers grains plus solubles (DDGS) supplementation (0, 10, 20, and 30%; DM basis), replacing steam-flaked (SF) corn in finishing diets, on characteristics of digestion (Exp. 1) and growth performance (Exp. 2) in calf-fed Holstein steers. In Exp.1, 4 cannulated Holstein steers (349 ± 12 kg) were used to evaluate treatment effects on characteristics of digestion. Ruminal NDF digestion tended to increase (quadratic effect, P = 0.09) and ruminal OM digestion decreased (linear effect, P = 0.01) with DDGS substitution. There were no treatment effects on duodenal flow of microbial N (MN). Substitution with DDGS increased (linear effect, P acetate:propionate molar ratio. In Exp.2, 144 Holsteins steer (112 ± 6 kg) were used in a 305-d trial to evaluate treatment effects on growth performance and carcass characteristics. During the initial 126 d, DDGS substitution increased ADG (linear effect, P = 0.03), G:F (quadratic effect, P = 0.03), and dietary NE (quadratic effect, P = 0.02), maximal for both at 20% DDGS inclusion rate. Based on estimated indispensable AA supply to the small intestine as a percentage of requirements during the initial 126-d period, histidine was first limiting followed by methionine. During the final 179-d period and overall (305-d feeding period), treatment effects on ADG and G:F were small (P ≥ 0.22). Compared with the other treatments, HCW was greater (3.4; P = 0.03) at the 20% level of DDGS substitution. The NE value for DDGS in SF corn-based diets for the calf-fed Holstein are consistent with current tabular standards. Extra-caloric value of DDGS as a metabolizable AA source is apparent during the initial growing phase. The UIP value of DDGS used in this study (35%) was considerably less than current tabular estimates (52%; NRC, 2000). PMID:23408804

  4. Impact of Industrialization on Grain Consumption and Countermeasures

    OpenAIRE

    Zeng, Jing

    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...

  5. 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....

  6. Systemic abnormalities in liver disease

    Institute of Scientific and Technical Information of China (English)

    Masami Minemura; Kazuto Tajiri; Yukihiro Shimizu

    2009-01-01

    Systemic abnormalities often occur in patients with liver disease. In particular, cardiopulmonary or renal diseases accompanied by advanced liver disease can be serious and may determine the quality of life and prognosis of patients. Therefore, both hepatologists and non-hepatologists should pay attention to such abnormalities in the management of patients with liver diseases.

  7. Abnormal pressure in hydrocarbon environments

    Science.gov (United States)

    Law, B.E.; Spencer, C.W.

    1998-01-01

    Abnormal pressures, pressures above or below hydrostatic pressures, occur on all continents in a wide range of geological conditions. According to a survey of published literature on abnormal pressures, compaction disequilibrium and hydrocarbon generation are the two most commonly cited causes of abnormally high pressure in petroleum provinces. In young (Tertiary) deltaic sequences, compaction disequilibrium is the dominant cause of abnormal pressure. In older (pre-Tertiary) lithified rocks, hydrocarbon generation, aquathermal expansion, and tectonics are most often cited as the causes of abnormal pressure. The association of abnormal pressures with hydrocarbon accumulations is statistically significant. Within abnormally pressured reservoirs, empirical evidence indicates that the bulk of economically recoverable oil and gas occurs in reservoirs with pressure gradients less than 0.75 psi/ft (17.4 kPa/m) and there is very little production potential from reservoirs that exceed 0.85 psi/ft (19.6 kPa/m). Abnormally pressured rocks are also commonly associated with unconventional gas accumulations where the pressuring phase is gas of either a thermal or microbial origin. In underpressured, thermally mature rocks, the affected reservoirs have most often experienced a significant cooling history and probably evolved from an originally overpressured system.

  8. Effect of Na Environment on growth rate of grain and nucleation of precipitate in F/M steel cladding under Sodium and Ar-gas environment at 650 .deg. C

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Yong; Kim, Ji Hyun [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of); Shin, Sang Hun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    During the design life time (30 to 60 years), the cladding and structural materials are exposed to liquid sodium and aged at the designed operation temperature. When cladding and structural materials exposed to high temperature liquid sodium, the constituents of the components dissolve and exist as various compounds. This can accelerate the dissolution of components into coolant or disrupt flow of coolant with cumulated obstacle in loop. This change can cause a degradation of mechanical strength of structure material and thermal efficiency of UCFR. Therefore, the thermochemical reaction research, on effects of liquid sodium on ferrite/martensite steel for a long time, should additionally be performed. The goal of this study is to investigate growth and nucleation of precipitates of ferrite/martensite steels in liquid sodium and its effect on grain growth. There are many changes such as Cr depletion, decarburization, segregation, precipitate and oxidation, affecting into microstructural evolution of the steels. In a specific procedure, the micro-structure and the surface phenomenon of ferrite/martensite steels that are exposed in liquid sodium at high temperature by using scanning electron microscope (SEM) and transmission electron microscope (TEM) have been investigated. After investigating precipitates formed at surface on liquid sodium and Ar-gas environments, the precipitates' Gibbs free energy is calculated with enthalpy and entropy included in the precipitates. Finally, the calculated values with diffusivity of components will become reason why the phases have different tendency on the growth rate of precipitates. As analyzing the chemical composition by TEM images, the correlation is investigated with supplementary materials. When Gr.92 is exposed to sodium containing oxygen, oxide is formed and there are depletion of Cr and presumably decarburization into sodium. So, the amount of M{sub 23}C{sub 6} is decreased. At Ar-gas environment, there is no

  9. Responses of ethylene and ACC in rice grains to soil moisture and their relations to grain filling

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The objectives of this study were to-investigate ethylene and 1-aminocylopropane-1-carboxylic acid (ACC) in rice grains and root bleeding sap during the grain filling period and their relationship to the grain filling rate.Two high lodging-resistant rice (Oryza sativa L.) cultivars were grown in pots or tanks.Three treatments,including well watered (WW),moderate soil-drying (MD) and severe soil-drying (SD),were conducted from 9 days of post-anthesis until maturity.The effects of chemical regulators on the concentrations of ethylene and ACC in the grains were also studied.The results show that MD significantly increased the grainfilling rate and grain weight,whereas SD significantly reduced the grain-filling rate and grain weight.Concentrations of ethylene and ACC in the grains were very high at the early grain filling stage and then sharply decreased during the linear period of grain growth.MD reduced the ACC concentrations and ethylene evolution rate,whereas SD remarkably increased the ACC concentrations and ethylene evolution rate.Both the ethylene evolution rate in rice grains and the ACC concentrations in the root-bleeding sap were significantly and positively correlated with the ACC concentrations in rice grains.The ethylene evolution rate was significantly and negatively correlated with the grain-filling rate.The application of amino-ethoxyvinylglycine (AVG),an inhibitor of ethylene synthesis,at 9-13 days of postanthesis significantly reduced the ACC concentrations and ethylene evolution rate of grains,but significantly enhanced the activities of sucrose synthase,ADP glucose pyrophosphorylase and soluble starch synthase.The results were reversed when ethephon,an ethylenereleasing agent,was applied.The results suggest that moderate soil drying during the grain-filling period in rice could inhibit the production of ethylene and ACC and therefore accelerate grain filling and increase grain weight.

  10. Texture evolution in grain-oriented electrical steel during hot band annealing and cold rolling.

    Science.gov (United States)

    Shin, S M; Birosca, S; Chang, S K; De Cooman, B C

    2008-06-01

    The optimization of magnetic and physical properties of electrical steel is imperative for many engineering applications. The key factors to improve magnetic properties are the steel composition as well as control of the crystallographic orientation and microstructure of the steel during processing. However, this requires careful control of processing at all stages of production. Under certain conditions of deformation and annealing, electrical steel can be produced to have favourable texture components. For grain-oriented (GO) electrical steels that are used in most transformer cores, a pronounced {110} Goss texture plays a vital role to achieve low power losses and high permeability. Essentially, Goss texture develops during secondary re-crystallization in GO electrical steels; however, the mechanism of the abnormal Goss grain growth is still disputed in the literature. In the current study, the influence of the annealing conditions on the development of annealing, cold rolling and re-crystallization textures of hot-rolled GO electrical steel were investigated in detail following each processing step. Furthermore, the orientation data from electron backscatter diffraction were used to evaluate the orientation-dependent stored energy of deformed grains after hot rolling. In the light of new findings in the present study, annealing and deformation texture development mechanisms were critically reviewed. PMID:18503668

  11. 层流作用下随机取向多晶粒生长的相场法模拟%Phase-field simulation of forced flow effect on random preferred growth direction of multiple grains

    Institute of Scientific and Technical Information of China (English)

    王军伟; 朱昌盛; 王智平; 冯力; 肖荣振

    2011-01-01

    为了更客观地再现强迫层流对多晶粒凝固过程的影响,自行设计了随机格子法以解决多个枝晶择优生长方向随机分布问题.以高纯丁二腈(SCN)为例,采用耦合流场的单相场模型研究强迫层流对多晶粒非等温生长过程的影响.结果表明:随机格子法可以更合理地处理枝晶择优取向随机分布问题,计算效率较高.当固相率较低时,熔体质点绕过枝晶流向下游侧,两枝晶臂之间的熔体流动速度值变大;在凝固计算时间小于1800Δt时,各个枝晶自由生长,上游侧枝晶臂均比下游侧枝晶臂发达;并且,熔体流入速度越快,固相率越高.当固相率较高时,多个枝晶臂相互交织,仅有未被枝晶包裹的残留熔体可以流动;同时,固相率趋于与熔体无流动时的固相率相同.%The random distribution problem of dendrite preferred growth direction was settled by random grid method.This method was used to study the influence of forced laminar flow effect on multiple grains during solidification.Taking high pure succinonitrile (SCN) undercooled melt as an example,the forced laminar flow effect on multiple grains was studied by phase-field model of single grain which coupled with flow equations at non-isothermal condition.The simulation results show that the random grid method can reasonably settle the problem of random distribution and is more effective.When the solid fraction is relatively low,melt particles flow around the downstream side of dendrite,and the flow velocity between two dendrite arms becomes high.At the stage of solidification time less than 1800Δt,every dendrite grows freely; the upstream dendrites are stronger than the downstream ones.The higher the melt flow rate,the higher the solid fraction.However,when the solid fraction is relatively high,the dendrite arm intertwins and only a little residual melt which is not encapsulated can flow; the solid fraction will gradually tend to equal to solid fraction

  12. 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.

  13. Effect of Free Air CO2 Enrichment (FACE) on the Growth and Grain Yield of Winter Wheat%FACE条件下冬小麦生长特征及产量构成的影响

    Institute of Scientific and Technical Information of China (English)

    韩雪; 郝兴宇; 王贺然; 林而达

    2012-01-01

    Simulating on the atmosphere CO2 concentration in 2050 in a wheat field, investigating on the growth and yield response of winter wheat to elevated CO2, enable people to estimate the impacts of elevated C02 on winter wheat in a CO2-rich world. Winter wheat (Triticum aestivum L. cv CA0493, high gluten wheat) was grown to maturity at ambient CO2 (415±16 μmol/mol) or elevated CO2 (550±17 μmol/mol) under 2 levels of N: normal N (NN, basal dressing N 118 kg/hm2+sidedressing N 70 kg/hm2) and low N (LN, basal dressing N 66 kg/hm2 + sidedressing N 17 kg/hm2) at FACE (Free Air CO2 Enrichment) system, to investigate the effects of elevated CO2 (550 μmol/mol) and N fertilizer input on height, flag leaf area and the top three leaves area, tiller number seasonal changes, grain yield and yield components of winter wheat. Results showed that elevated CO2 increased wheat height by 5.12% at jointing stage, the scale of increasing was larger under normal N than low N input. Elevated CO2 increased flag leaf area and the top three leaves area by 14.87%, 10.02% at flowering stage, respectively. Increased leaf size under elevated CO2 was determined by longer leaf length (8.97%). Elevated CO2 tend to increase the tiller number under normal N input. Grain yield increased by 18.3% under elevated CO2 (P<0.05), with 6% in low N input and 31.4% in normal N input. Panicle number per square meter and grain number per panicle increased by 5.3% and 14.5% (P<0.05) under elevated CO2, and the increase amplitude was more in normal N than low N input. Infertile spikelet number decreased significantly by 11.12% at high CO2, while thousand grains weight showed no significant change under elevated CO2. Elevated CO2 reduced the degenerated spikelet number, thus increased grain number per panicle, which accounted for the yield increase under elevated CO2.%模拟2050年冬小麦生长的CO2浓度下,冬小麦生长和产量的响应,有助于评价未来CO2浓度升高对小麦生产的影响.

  14. Control and characterization of individual grains and grain boundaries in graphene grown by chemical vapour deposition

    Science.gov (United States)

    Yu, Qingkai; Jauregui, Luis A.; Wu, Wei; Colby, Robert; Tian, Jifa; Su, Zhihua; Cao, Helin; Liu, Zhihong; Pandey, Deepak; Wei, Dongguang; Chung, Ting Fung; Peng, Peng; Guisinger, Nathan P.; Stach, Eric A.; Bao, Jiming; Pei, Shin-Shem; Chen, Yong P.

    2011-06-01

    The strong interest in graphene has motivated the scalable production of high-quality graphene and graphene devices. As the large-scale graphene films synthesized so far are typically polycrystalline, it is important to characterize and control grain boundaries, generally believed to degrade graphene quality. Here we study single-crystal graphene grains synthesized by ambient chemical vapour deposition on polycrystalline Cu, and show how individual boundaries between coalescing grains affect graphene’s electronic properties. The graphene grains show no definite epitaxial relationship with the Cu substrate, and can cross Cu grain boundaries. The edges of these grains are found to be predominantly parallel to zigzag directions. We show that grain boundaries give a significant Raman ‘D’ peak, impede electrical transport, and induce prominent weak localization indicative of intervalley scattering in graphene. Finally, we demonstrate an approach using pre-patterned growth seeds to control graphene nucleation, opening a route towards scalable fabrication of single-crystal graphene devices without grain boundaries.

  15. Effect of gamma radiation on the growth of Aspergillus Flavus aflatoxins producer and on the use of polymerase chain reaction technique (PCR) in samples of maize grains artificially inoculated

    International Nuclear Information System (INIS)

    The aim of this present study was to verify the effects of gamma radiation on the growth of Aspergillus flavus Link aflatoxins producer; to demonstrate the application of Polymerase Chain Reaction (PCR) technique in the diagnostic of A. Flavus, as well to verify the effect of radiation in the profile of DNA bands. Twenty samples of grains maize with 200 g each were individually irradiated with 20 kGy, to eliminate the microbial contamination. In following, the samples were inoculated with an toxigenic A. flavus (1x106 spores/ml), incubated for 15 days at 25 deg C with a relative humidity of around 97,5% and irradiated with 0, 2; 5 and 10 kGy. The samples, 5 to each dose of irradiation, were individually analyzed for the number of fungal cells, water activity, viability test (fluorescein diacetate and ethidium bromide), PCR and aflatoxins (AFB) detection. The results showed that the doses used were effective in reducing the number of Colony Forming Units (CFU/g) mainly the doses of 5 and 10 kGy. In addition, the viability test showed a decrease of viable cells with increase of irradiation doses. The reduction of AFB1 and AFB-2, was more efficient with the use of 2 kGy in comparison with the dose of 5 kGy, while the dose of 10 kGy, degraded the aflatoxins. Thereby, it was observed that AFB2 showed to be more radiosensitive. The use of PCR technique showed the presence of DNA bands, in all samples. (author)

  16. Effect of yeast-derived products and distillers dried grains with solubles (DDGS) on growth performance, gut morphology, and gene expression of pattern recognition receptors and cytokines in broiler chickens.

    Science.gov (United States)

    Alizadeh, M; Rodriguez-Lecompte, J C; Rogiewicz, A; Patterson, R; Slominski, B A

    2016-03-01

    An experiment was carried out to investigate the effect of yeast-derived products and distillers' dried grains with solubles (DDGS) on growth performance, small intestinal morphology, and innate immune response in broiler chickens from 1 to 21 d of age. Nine replicates of 5 birds each were assigned to dietary treatments consisting of a control diet without antibiotic (C), and diets containing 11 mg/kg of virginiamycin, 0.25% of yeast cell wall (YCW), 0.2% of a commercial product Maxi-Gen Plus, 0.025% of nucleotides, 0.05% of nucleotides, or a diet containing 10% of DDGS. On d 21, 5 birds per treatment were euthanized and approximately 5-cm long duodenum, jejunum, and ileum segments were collected for intestinal morphology measurements. Cecal tonsils and spleen were collected to measure the gene expression of toll-like receptors TLR2b, TLR4, and TLR21, macrophage mannose receptor (MMR), and cytokines IFN-γ, IL-12, IL-10, and IL-4. No significant difference was observed for growth performance parameters. However, diets containing 0.05% of nucleotides and YCW significantly increased (P < 0.05) villus height in the jejunum. Furthermore, the number of the goblet cells per unit area in the ileum was increased (P < 0.05) in diets supplemented with yeast-derived products. The expression of TLR2b in the spleen was down-regulated for diets supplemented with nucleotides and antibiotic. In addition, lower expression of TLR21 and MMR was observed in the spleen of birds receiving yeast-derived products and antibiotic. However, expression of TLR4 in the spleen was up-regulated in diets supplemented with YCW and nucleotides. The expression of IFN-γ and IL-12 was down-regulated in the spleen of birds fed diets supplemented with yeast-derived products. In addition, inclusion of YCW, Maxi-Gen Plus, or 0.05% of nucleotides down-regulated the expression of IL-10 and IL-4 in the cecal tonsils. In conclusion, down-regulation of receptors and cytokines in spleen and cecal tonsils of

  17. Microstructural evolutions and stability of gradient nano-grained copper under tensile tests and subsequent storage

    Science.gov (United States)

    Chen, W.; You, Z. S.; Tao, N. R.; Lu, L.

    2015-08-01

    A gradient nano-grained (GNG) surface layer is produced on a bulk coarse-grained Cu by means of a surface mechanical grinding treatment. Homogeneous grain coarsening induced by mechanical deformation is observed in the GNG Cu layer under tensile tests at both 300 K and 123 K. The concurrent grain coarsening during tensile deformation is proven to be also thermally activated, because the extent of grain coarsening of the GNG Cu layer is less significant at 123 K than at 300 K, although a higher flow stress is achieved at 123 K. During the subsequent storage at 258 K after tensile tests, no obvious change can be found for the grain size in the GNG Cu layer deformed at 300 K. In contrast, widespread abnormal grain coarsening is frequently observed in the GNG Cu layer deformed at 123 K and stored for 100 days, which may be caused by the higher stored energy in the non-equilibrium grain boundary structures.

  18. Autism and chromosome abnormalities-A review.

    Science.gov (United States)

    Bergbaum, Anne; Ogilvie, Caroline Mackie

    2016-07-01

    The neuro-behavioral disorder of autism was first described in the 1940s and was predicted to have a biological basis. Since that time, with the growth of genetic investigations particularly in the area of pediatric development, an increasing number of children with autism and related disorders (autistic spectrum disorders, ASD) have been the subject of genetic studies both in the clinical setting and in the wider research environment. However, a full understanding of the biological basis of ASDs has yet to be achieved. Early observations of children with chromosomal abnormalities detected by G-banded chromosome analysis (karyotyping) and in situ hybridization revealed, in some cases, ASD associated with other features arising from such an abnormality. The introduction of higher resolution techniques for whole genome screening, such as array comparative genome hybridization (aCGH), allowed smaller imbalances to be detected, some of which are now considered to represent autism susceptibility loci. In this review, we describe some of the work underpinning the conclusion that ASDs have a genetic basis; a brief history of the developments in genetic analysis tools over the last 50 years; and the most common chromosome abnormalities found in association with ASDs. Introduction of next generation sequencing (NGS) into the clinical diagnostic setting is likely to provide further insights into this complex field but will not be covered in this review. Clin. Anat. 29:620-627, 2016. © 2016 Wiley Periodicals, Inc. PMID:27012322

  19. Influence of anisotropic grain boundary properties on the evolution of grain boundary character distribution during grain growth—a 2D level set study

    International Nuclear Information System (INIS)

    The present study elaborates on a 2D level set model of polycrystal microstructures that was recently established by adding the influence of anisotropic grain boundary energy and mobility on microstructure evolution. The new model is used to trace the evolution of grain boundary character distribution during grain growth. The employed level set formulation conveniently allows the grain boundary characteristics to be quantified in terms of coincidence site lattice (CSL) type per unit of grain boundary length, providing a measure of the distribution of such boundaries. In the model, both the mobility and energy of the grain boundaries are allowed to vary with misorientation. In addition, the influence of initial polycrystal texture is studied by comparing results obtained from a polycrystal with random initial texture against results from a polycrystal that initially has a cube texture. It is shown that the proposed level set formulation can readily incorporate anisotropic grain boundary properties and the simulation results further show that anisotropic grain boundary properties only have a minor influence on the evolution of CSL boundary distribution during grain growth. As anisotropic boundary properties are considered, the most prominent changes in the CSL distributions are an increase of general low-angle Σ1 boundaries as well as a more stable presence of Σ3 boundaries. The observations also hold for the case of an initially cube-textured polycrystal. The presence of this kind of texture has little influence over the evolution of the CSL distribution. Taking into consideration the anisotropy of grain boundary properties, grain growth alone does not seem to be sufficient to promote any significantly increased overall presence of CSL boundaries. (paper)

  20. Skin - abnormally dark or light

    Science.gov (United States)

    ... ency/article/003242.htm Skin - abnormally dark or light To use the sharing features on this page, ... the hands. The bronze color can range from light to dark (in fair-skinned people) with the ...

  1. Artabas of grain or artabas of grains?

    OpenAIRE

    Clarysse, Willy

    2014-01-01

    Survey of the use of the singular and plural with Greek words for grain. The original plural gives way to the singular in the course of the Hellenistic period, but the plural reappears in the later Roman period for barley, whereas wheat, for which σῖτος is then used rather than πυρός, occurs in the singular. There are, however, a number of exceptions to the general picture, often depending on the case in which the words occur.

  2. Nucleation and growth of a multicomponent metallic glass@

    Indian Academy of Sciences (India)

    Arun Pratap; K G Raval; Ajay Gupta; S K Kulkarni

    2000-06-01

    The metallic glass samples of Fe67Co18B14Si1 (2605CO), prepared by the melt spinning technique were procured from the Allied Corporation. The kinetics of crystallization of this multicomponent glassy alloy is studied using differential scanning calorimetry (DSC). The crystallization data have been examined in terms of modified Kissinger and Matusita equations for the non-isothermal crystallization. The results show enhanced bulk nucleation in general. At high heating rates added to it is surface induced abnormal grain growth resulting in fractal dimensionality.

  3. 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.

  4. Analysis of the Changes in China’s Grain Production Costs over the Past Decade

    Institute of Scientific and Technical Information of China (English)

    Shuangjin; WANG; Chen; LIANG

    2015-01-01

    China’s grain production cost has risen constantly since 2003. This paper starts from the grain production cost changes of unit area and unit quality,to analyze the reasons for China’s grain production cost change in the last decade. It points out that the direct cause of changes in grain production cost is the steady growth of material and services costs,the fastest growth of labor costs and fast growth of land costs. The indirect cause of grain production high cost is the low efficiency in numerous and dispersive farmer production management,obviously insufficient agricultural infrastructure construction,waste phenomenon grain in production process and low contribution rate of agricultural technology.On this basis,it is recommended to reduce China’s grain production cost and improve grain production conditions.

  5. Growth and yield of corn grain and green ear in competition with weeds Crescimento e rendimento de espigas verdes e de grãos de milho em competição com plantas daninhas

    Directory of Open Access Journals (Sweden)

    P.S.L Silva

    2009-12-01

    Full Text Available Studies on plant growth are interesting because they provide explanations for the factors that influence yield in various crops. The objective of this work was to evaluate growth and yield in corn cultivar AG1051, when in competition with weeds. Cultivar AG 1051 was submitted to two groups of treatments: weed control, and sampling periods for dry biomass evaluation. The weed control treatments consisted of hoeing (two hoeings performed at 20 and 40 days after sowing and no hoeing. Sampling periods consisted of collecting the above-ground part and roots of corn every fifteen days, until 105 days after sowing (DAS; the first sampling was performed 30 DAS. A completely randomized block design with ten replicates was used. For the characteristics evaluated in a single season, statistical analyses were carried out as a random block experiment. For the characteristics evaluated in several periods, statistical analyses were carried out as random blocks with split-plots (weed control assigned to plots. Fourteen weed species, unevenly distributed throughout the experimental area, were the most important. The growth observed for the above-ground part and root system of corn was 30% smaller in the non-hoed plots, compared to the hoed plots. Lack of weed control increased dry matter of the above-ground part of the weeds and reduced the number of unhusked and husked marketable green ears by 23% and 49%, respectively. Grain yield reduction caused by lack of weed control reached 38%.Apesar de trabalhosos, os estudos sobre o crescimento são de interesse porque fornecem explicações sobre os fatores que influenciam o rendimento das culturas. O objetivo do presente trabalho foi avaliar o crescimento e o rendimento de espigas verdes e de grãos do cultivar de milho AG 1051, em competição com plantas daninhas. Esse cultivar foi submetido a dois grupos de tratamento: controle de plantas daninhas e épocas de amostragem para avaliação da biomassa seca. Os

  6. Memetics clarification of abnormal behavior

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: Biological medicine is hard to fully and scientifically explain the etiological factor and pathogenesis of abnormal behaviors; while, researches on philosophy and psychology (including memetics) are beneficial to better understand and explain etiological factor and pathogenesis of abnormal behaviors. At present, the theory of philosophy and psychology is to investigate the entity of abnormal behavior based on the views of memetics.METHODS: Abnormal behavior was researched in this study based on three aspects, including instinctive behavior disorder, poorly social-adapted behavior disorder and mental or body disease associated behavior disorder. Most main viewpoints of memetics were derived from "The Meme Machine", which was written by Susan Blackmore. When questions about abnormal behaviors induced by mental and psychological diseases and conduct disorder of teenagers were discussed, some researching achievements which were summarized by authors previously were added in this study, such as aggressive behaviors, pathologically aggressive behaviors, etc.RESULTS: The abnormal behaviors mainly referred to a part of people's substandard behaviors which were not according with the realistic social environment, culture background and the pathologic behaviors resulted from people's various psychological diseases. According to the theory of "meme", it demonstrated that the relevant behavioral obstacles of various psychological diseases, for example, the unusual behavior of schizophrenia, were caused, because the old meme was destroyed thoroughly but the new meme was unable to establish; psychoneurosis and personality disorder were resulted in hard establishment of meme; the behavioral obstacles which were ill-adapted to society, for example, various additional and homosexual behaviors, were because of the selfish replications and imitations of "additional meme" and "homosexual meme"; various instinct behavioral and congenital intelligent obstacles were not significance

  7. 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.

  8. 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.

  9. Thyroid abnormality in perimenopausal women with abnormal uterine bleeding

    Directory of Open Access Journals (Sweden)

    Prasanna Byna

    2015-11-01

    Full Text Available Background: AUB is a common but complicated clinical presentation and occurs in 15-20% of women between menarche to menopause and significantly affects the women's health. Women with thyroid dysfunction often have menstrual irregularities, infertility and increased morbidity during pregnancy. The objective of present study is to find the correlation between thyroid disorders and AUB in perimenopausal women attending gynecology OPD. Methods: In the present study, fifty five patients with AUB were included and were evaluated for the cause including thyroid abnormality. Thyroid function tests were done in all patients. Results: Among 55 patients, 12 patients were diagnosed as hypothyroidism and 7 as hyperthyroidism, women with AUB 36 (65.4% were euthyroid. Among 19 women with thyroid abnormality, heavy menstrual bleeding was seen in 8 (42% women, 6 (31.57% had polymenorrhagia, 5 (26.31% had oligomenorrhoea. The frequent menstrual abnormality in women with hypothyroidism (12 women was heavy menstrual bleeding in 5 (41.6% women, 3 (25% had oligomennorhoea, 4 (33.3% had polymenorrhagia. Out of 7 women with hyperthyroidism, 2 (28.57% had oligomenorrhoea, 3 (42.8% had heavy menstrual bleeding, 2 (28.57% had polymenorrhagia. In a total of 55 patients with AUB, 11 (20% had structural abnormalities in uterus and ovaries. 5 (9% had adenomyosis, 3 (5.4% had ovarian cysts, 3 (5.4% had fibroids. Conclusions: It is important to screen all women for thyroid abnormality who are presenting with AUB especially with non-structural causes of AUB. Correction of thyroid abnormalities also relieves AUB. This will avoid unnecessary hormonal treatment and surgery. [Int J Res Med Sci 2015; 3(11.000: 3250-3253

  10. Study on Haploid Inducing and Its Meiotic Abnormality in Maize

    Institute of Scientific and Technical Information of China (English)

    TANG Qi-lin; FENG Yun-chao; HAN Xue-li; ZHENG Ming-min; RONG Ting-zhao

    2009-01-01

    The haploid-inducing line Stock 6 was used to produce haploid maize and expected to obtain maize haploid plants successfully. The detailed meiotic studies on selected haploid maize (n=x=10) were conducted. Cytogenetie analysis revealed a high frequency of meiotic abnormality occurred in both meiosis Ⅰ and meiosis Ⅱ. During the prophase I, univalents were common configurations, and there were bivalents or trivalents in some pollen mother cells, however, a few cells containing five bivalents were also observed. After prophase I, chromosomes did not congregate in a single metaphase plate but they were scattered in the cytoplasm. At anaphase I, the chromosome distribution was highly irregular with almost all possible combinations. In some cells, chromosomes were grouped into the three or four masses and several spindles appeared. At the tetrad stage of meiosis Ⅱ, cytokinesis splitting abnormality occurred, and a variety of diad, triad, tetrad, pentad, hexad, as well as decury microspores were easily observed. As a consequence of abnormalities of the two meiotic stages, various microspores and the pollen grains with different size were formed, and its pollen grains were almost completely sterile.

  11. 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.

  12. Knee loading for abnormal gait

    OpenAIRE

    Hutchison, J.; Madsen, D.; Norman, T. L.; -Blaha, J. D.

    2014-01-01

    The purpose of the study was to develop a mathematical model for determining knee loads for abnormal gait. Abnormal gait was defined as a person with varus, i.e. “bowleggedness”, or a person who had an external rotation of the femur (or the inability to internally rotate the femur) which caused an indirect varus in the forward positions of gait. Conditions such as these have been observed clinically to result in increased wear on the medial condyle of total knee replacements. This problem was...

  13. Secondary Abnormalities of Neurotransmitters in Infants with Neurological Disorders

    Science.gov (United States)

    Garcia-Cazorla, A.; Serrano, M.; Perez-Duenas, B.; Gonzalez, V.; Ormazabal, A.; Pineda, M.; Fernandez-Alvarez, E.; Campistol, J. M. D.; Artuch, R. M. D.

    2007-01-01

    Neurotransmitters are essential in young children for differentiation and neuronal growth of the developing nervous system. We aimed to identify possible factors related to secondary neurotransmitter abnormalities in pediatric patients with neurological disorders. We analyzed cerebrospinal fluid (CSF) and biogenic amine metabolites in 56 infants…

  14. Forecasting grain production costs in the backdrop of economic cycles

    Institute of Scientific and Technical Information of China (English)

    蓝海涛; 姜长云

    2009-01-01

    This research indicates that with the changes in economic cycles, China’s production costs are experiencing "wave-shaped" spiral growth. From 2004 to 2008, China’s grain production costs increased rapidly, with the primary driving force the rapid growth of labor, land and material costs. In the middle stage of industrialization, China’s grain production costs will experience spiral growth following economic cyclical fluctuations, entering relative stability after a certain period. From 2009 to around 2012, grain production costs will drop, but average production costs may be higher than in the current upward cycle. From 2013 to around 2020, grain production costs will rise again and be much higher than in the current upward cycle.

  15. Normalisation of a severely abnormal ductus venosus Doppler flow velocity waveform in a growth-retarded fetus with absent end-diastolic flow in the umbilical artery and congenital anomalies.

    Science.gov (United States)

    Müller, T; Rehn, M; Girschick, G; Kristen, P; Dietl, J

    2001-01-01

    Doppler recordings of fetal venous blood flow seem to be superior to arterial velocimetry and CTG concerning the prediction of fetal outcome and optimal time of delivery in pregnancies with fetal growth retardation and AREDV. An improvement of arterial Doppler flow velocities has been described. We report the reappearance of a normal end-diastolic flow velocity in a ductus venosus temporarily showing reversed end-diastolic flow in a growth-retarded fetus with congenital anomalies. This normalization was accompanied by an improvement of the CTG, a loss of umbilical vein pulsations, a reappearance of umbilical diastolic flow and a progressive return of cerebral and venous blood flow into the 'normal' range. Improvement of fetal condition may be the explanation for our observation.

  16. Kinetics of individual grains during recrystallization of cold-rolled copper

    DEFF Research Database (Denmark)

    Lin, Fengxiang; Zhang, Yubin; Poulsen, S.O.;

    2015-01-01

    The formation of a recrystallization texture is closely related to the nucleation and growth of recrystallizing grains, which may vary from grain to grain. Cube texture is a commonly observed recrystallization texture in face centered cubic metals of medium to high stacking fault energy after hea...

  17. Simultaneous monitoring of stored grain with relative humidity, temperature, and carbon dioxide sensors

    Science.gov (United States)

    Grain moisture content (MC) and temperature (T) are the primary factors affecting grain deterioration in storage. If these factors are not properly monitored and controlled, grain quality can deteriorate quickly due to mold growth and insect infestation. This research examined use of relative humi...

  18. 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.

  19. Cardiac abnormalities after subarachnoid hemorrhage

    NARCIS (Netherlands)

    Bilt, I.A.C. van der

    2016-01-01

    Aneurysmal subarachnoid hemorrhage(aSAH) is a devastating neurological disease. During the course of the aSAH several neurological and medical complications may occur. Cardiac abnormalities after aSAH are observed often and resemble stress cardiomyopathy or Tako-tsubo cardiomyopathy(Broken Heart Syn

  20. Congenital abnormalities in methylmercury poisoning

    Energy Technology Data Exchange (ETDEWEB)

    Gilani, S.H.

    1975-04-01

    This study was undertaken to determine the teratogenic potential of methylmercury on chick embryogenesis. Methylmercuric chloride was dissolved in sodium bicarbonate (0.2%) and administered to the chick embryos at doses ranging from 0.0009 to 0.010 mg per egg. The injections were made at days 2 and 3 on incubation (Groups A and B). All the embryos including controls were examined on the 7th day of incubation. Methylmercury poisoning was observed to be both embryolethal and teratogenic. Within the two groups, embryolethality was higher in Group A. The following congenital abnormalities were observed: exencephaly, shortened and twisted limbs, microphthalmia, shortened and twisted neck, beak abnormalities, everted viscera, reduced body size and hemorrhage all over the body. Exencephaly and limb abnormalities were very common. No differences in the incidence and types of gross abnormalities within both the groups (A and B) were noted. The incidence of malformations among the controls was low. The results of present investigation show that methylmercury poisoning is both embryolethal and teratogenic to early chick embryogenesis. (auth)

  1. Grain Marketing Tools: A Survey of Illinois Grain Elevators

    OpenAIRE

    Whitacre, Rick C.; Spaulding, Aslihan D.

    2007-01-01

    As with most sectors of the agriculture economy, the U. S. country grain elevator industry has experienced considerable consolidation and concentration. By the same token, the country elevator's customer base (grain producers and landlords) has also changed rather dramatically as grain production takes place on larger and fewer farms. The profitability of operating a country elevator is directly related to the volume of grain the country elevator purchases over the course of a marketing year....

  2. 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

  3. Surface Roughness and Grain Size Characterization of Annealing Temperature Effect For Growth Gallium and Tantalum Doped Ba0.5 Sr0.5TiO3Thin Film

    Directory of Open Access Journals (Sweden)

    Irzaman

    2009-01-01

    Full Text Available Thin films 10 % gallium oxide doped barium strontium titanate (BGST and 10 % tantalum oxide doped barium strontium titanate (BTST were prepared on p-type Si (100 substrates using chemical solution deposition (CSD method with 1.00 M precursor. The films were deposited by spin coating method with spinning speed at 3000 rpm for 30 seconds. The post deposition annealing of the films were carried out in a furnace at 200oC, 240oC, 280oC (low temperature for 1 hour in oxygen gas atmosphere. The surface roughness and grain size analysis of the grown thin films are described by atomic force microscope (AFM method at 5000 nm x 5000 nm area. The rms surface roughness BGST thin films at 5000 nm x 5000 nm area are 0.632 nm, 0.564 nm, 0.487 nm for temperature 200oC, 240oC, 280oC, respectively, whereas the grain size (mean diameter are 238.4 nm, 219.0 nm, 185.1 nm for temperature 200oC, 240oC, 280oC, respectively. In fact, to increase annealing temperature from 200oC to 280oC would result in decreasing the rms roughness and grain size. Therefore, rms roughness and grain size would have the strong correlation annealing temperature.

  4. Short-term high temperature growth conditions during vegetative-to-reproductive phase transition irreversibly compromise cell wall invertase-mediated sucrose catalysis and microspore meiosis in grain sorghum

    Science.gov (United States)

    Grain sorghum (Sorghum bicolor L. Moench) crop yield is significantly compromised by high temperature stress-induced male sterility, and is attributed to reduced cell wall invertase (CWI)-mediated sucrose hydrolysis in microspores and anthers leading to altered carbohydrate metabolism and starch def...

  5. Densification and grain growth kinetics of Ce0.9Gd0.1O1.95 in tape cast layers: The influence of porosity

    DEFF Research Database (Denmark)

    Ni, De Wei; Esposito, Vincenzo; Foghmoes, Søren Preben Vagn;

    2014-01-01

    The sintering behavior of Ce0.9Gd0.1O1.95(CGO) tape cast layers with different porosity was investigated by an extensive characterization of densification, microstructural evolution, and applying the constitutive laws of sintering. The densification of CGO tapes associates with grain coarsening p...

  6. Surface Roughness and Grain size Characterization of Effect of Annealing Temperature for Growth Gallium and Tantalum Doped Ba0.5 Sr0.5 TiO3 Thin Film

    International Nuclear Information System (INIS)

    Thin films 10 % gallium oxide doped barium strontium titanate (BGST) and 10 % tantalum oxide doped barium strontium titanate (BTST) were prepared on p-type Si (100) substrates using chemical solution deposition (CSD) method with 1.00 M precursor. The films were deposited by spin coating method with spinning speed at 3000 rpm for 30 seconds. The post deposition annealing of the films were carried out in a furnace at 200oC, 240oC, 280oC (low temperature) for 1 hour in oxygen gas atmosphere. The surface roughness and grain size analysis of the grown thin films are described by atomic force microscope (AFM) method at 5000 nm x 5000 nm area. The rms surface roughness BGST thin films at 5000 nm x 5000 nm area are 0.632 nm, 0.564 nm, 0.487 nm for temperature 200oC, 240oC, 280oC, respectively, whereas the grain size (mean diameter) are 238.4 nm, 219.0 nm, 185.1 nm for temperature 200oC, 240oC, 280oC, respectively. In fact, to increase annealing temperature from 200oC to 280oC would result in decreasing the rms roughness and grain size. Therefore, rms roughness and grain size would have the strong correlation annealing temperature. (author)

  7. Recrystallization behaviour of fine-grained magnesium alloy after hot deformation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Annealing behaviors of hot-deformed magnesium alloy AZ31 were studied at temperatures from 300 to 673 K by optical and SEM/EBSD metallographic observation. Temperature dependence of the average grain size(D) is categorized into three temperature regions, i.e. an incubation period for grain growth, rapid grain coarsening, and normal grain growth. The number of fine grains per unit area, however, is reduced remarkably even in incubation period. This leads to grain coarsening taking place continuously in the whole temperature regions. In contrast, the deformation texture scarcely changes even after full annealing at high temperatures. It is concluded that the annealing processes operating in hot-deformed magnesium alloy with continuous dynamic recrystallized grain structures can be mainly controlled by grain coarsening accompanied with no texture change, that is, continuous static recrystallization.

  8. Intragranular nucleation sites of massive gamma grains in a TiAl-based alloy

    DEFF Research Database (Denmark)

    Dey, Suhash Ranjan; Bouzy, E.; Hazotte, A.

    2007-01-01

    Massive gamma grains were generated in a TiAl-based alloy through ice-water quenching from the alpha domain. Apart from those located along alpha(2)/alpha(2) grain boundaries, a few massive gamma grains were detected inside the alpha(2) grains. Some of these intragranular grains were revealed...... to be attached to particular alpha(2) twins (K-1: "{212103}" eta(1): ), in a Blackburn orientation relationship with them. Others were identified as developing in feathery colonies of similar crystallographic orientation. Whatever the nucleation site, further growth of all massive gamma grains involves...

  9. 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.

  10. 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.

  11. Titanium oxide as substrate for neural cell growth.

    Science.gov (United States)

    Carballo-Vila, Mónica; Moreno-Burriel, Berta; Chinarro, Eva; Jurado, José R; Casañ-Pastor, Nieves; Collazos-Castro, Jorge E

    2009-07-01

    Titanium oxide has antiinflammatory activity and tunable electrochemical behavior that make it an attractive material for the fabrication of implantable devices. The most stable composition is TiO2 and occurs mainly in three polymorphs, namely, anatase, rutile, and brookite, which differ in its crystallochemical properties. Here, we report the preparation of rutile surfaces that permit good adherence and axonal growth of cultured rat cerebral cortex neurons. Rutile disks were obtained by sinterization of TiO2 powders of commercial origin or precipitated from hydrolysis of Ti(IV)-isopropoxide. Commercial powders sintered at 1300-1600 degrees C produced rutile surfaces with abnormal grain growth, probably because of impurities of the powders. Neurons cultured on those surfaces survived in variable numbers and showed fewer neurites than on control materials. On the other hand, rutile sintered from precipitated powders had less contaminants and more homogenous grain growth. By adjusting the thermal treatment it was possible to obtain surfaces performing well as substrate for neuron survival for at least 10 days. Some surfaces permitted normal axonal elongation, whereas dendrite growth was generally impaired. These findings support the potential use of titanium oxide in neuroprostheses and other devices demanding materials with enhanced properties in terms of biocompatibility and axon growth promotion. PMID:18481786

  12. Kabuki Syndrome: a case report with severe ocular abnormalities

    Directory of Open Access Journals (Sweden)

    Flavio Mac Cord Medina

    2013-10-01

    Full Text Available Kabuki syndrome is a rare congenital anomaly, characterized by five fundamental features, the "Pentad of Niikawa": dysmorphic facies, skeletal anomalies, dermatoglyphic abnormalities, mild to moderate mental retardation and postnatal growth deficiency. Patients present characteristic external ocular features, nonetheless they may also present significant ocular abnormalities. We report a case of a brazilian child diagnosed with Kabuki syndrome, addressing the clinical features observed, with emphasis on the ocular manifestations. This case highlights the existence of this syndrome and all of its complexity. The identification of preventable causes of loss of vision underlines the value of detailed ophthalmologic examination of Kabuki syndrome patients.

  13. Ostwald Ripening of Diffusion-Limited Small-Size Precipitates at Grain Boundaries

    OpenAIRE

    A.V. Koropov

    2012-01-01

    The paper describes a theoretical study of the Ostwald ripening of two-dimensional small-size precipitates of a newly formed phase at the grain boundary of finite thickness, taking into account the diffusion of impurity atoms from the grain interior to the grain boundary. The precipitate growth is believed to be limited by the impurity-atom diffusion in the grain boundary. The asymptotic time dependences are found for the average and critical precipitate radius, supersaturation of solid solut...

  14. Effect of initial grain size on texture evolution and magnetic properties in nonoriented electrical steels

    International Nuclear Information System (INIS)

    The magnetic properties of nonoriented electrical steels are influenced by the grain size and crystallographic texture. The technologies used to control the grain size in nonoriented electrical steels are approaching their limits. However, there is still some room for improvement of the magnetic properties through texture control. Hot-band annealing is known to be one of the most effective processing stages for texture modification. In this study, two types of initial grain sizes prior to cold rolling are obtained by different hot-band annealing. The effect of initial grain size on texture evolution and magnetic properties in nonoriented electrical steels containing 2% Si is examined. The specimens having different initial grain sizes have significantly different textures in the cold-rolled state and the annealed state. During the recrystallization stage, new grains formed in the coarse-grained specimens have stronger Goss but weaker γ-fibre texture than those in the fine-grained specimens. During the grain growth after complete recrystallization, the coarse-grained specimens still have weaker γ-fibre texture than the fine-grained specimens. The magnetic induction of the coarse-grained specimens is always higher at the same temperature than that of the fine-grained specimens. The core loss of the coarse-grained specimens is lower at the same temperature than that of fine-grained specimens. However, the improvement of the core loss becomes less pronounced as the annealing temperature increases.

  15. Radiological appearances of sinonasal abnormalities

    Energy Technology Data Exchange (ETDEWEB)

    El-Beltagi, A.H.; Sobeih, A.A.; Valvoda, M.; Dahniya, M.H.; Badr, S.S

    2002-08-01

    The aim of this pictorial review is to present a variety of abnormalities of the sinonasal cavities to emphasize the diversity of lesions occurring in this region. These include congenital, neoplastic and granulomatous disorders and some allergic and inflammatory lesions with uncommon radiological appearances, as well as expanding lesions of the facial bones or of dental origin with secondary involvement of the related sinus(es). El-Beltagi, A.H. et al. (2002). Clinical Radiology 57, 702-718.

  16. Is Dark Energy Abnormally Weighting?

    OpenAIRE

    Fuzfa, A.; Alimi, J. -M.

    2006-01-01

    We present a new interpretation of dark energy in terms of an \\textit{Abnormally Weighting Energy} (AWE). This means that dark energy does not couple to gravitation in the same way as ordinary matter, yielding a violation of the weak and strong equivalence principles on cosmological scales. The resulting cosmological mechanism accounts for the Hubble diagram of type Ia supernovae in terms of both cosmic acceleration and variation of the gravitational constant while still accounting for the pr...

  17. 小儿正常和异常生长发育知识网络课程的开发与实践%Development and practice of online courses on knowledge about children's normal and abnormal growth and development

    Institute of Scientific and Technical Information of China (English)

    苏喆; 古玉芬; 马华梅; 李燕虹; 陈秋莉; 张军; 蒋小云

    2015-01-01

    Growth and development is one of the basis of pediatrics, and growth disorder is a clinical problem facing every pediatrician.We aim at creating a set of online courses on knowledge about children's normal and abnormal growth and development.The courses, dominated by CAI courseware, make use of modern means of Internet and multimedia, abundant actual clinical materials to carry out lively and effective online teaching with various levels and targets, providing users with valuable learning resources beyond theoretical knowledge in books.Practice proves that this set of courses have a positively practical value for undergraduates, postgraduates and pediatricians, and will become an important style of learning related to pediatric growth and development disorders.%生长发育是儿科学的基础之一,生长发育障碍是每个儿科医生都会面临的临床问题。该课题旨在开发创建一套关于小儿正常和异常生长发育知识的网络课程,它以CAI课件为主导,利用现代网络和多媒体手段,通过丰富的实际临床素材,分层次、有目标地进行生动有效的网络教学,为使用者提供书本理论知识以外的宝贵学习资源。实践表明:该课程对本科生、研究生和儿科医生均有积极的实用价值,将成为儿科生长发育障碍学习的重要学习方式。

  18. Grain size reduction by electromagnetic stirring inside gold alloys

    Science.gov (United States)

    Ernst, R.; Mangelinck-Noël, N.; Hamburger, J.; Garnier, C.; Ramoni, P.

    2005-06-01

    The final properties of cast materials depend greatly on the solidification process undergone by the material. In this paper, we study gold alloys dedicated to the watch industry and jewellery in the framework of a research collaboration with the Metalor Company. The aim is to improve the concentration homogeneity of the ingots by controlling the solidification step. It can be achieved by reducing segregations by a decrease in the grain size. For this purpose, we set up a multiphase electromagnetic stirring of the melt to favour the growth of finer grains and improve the homogeneity of the composition. We first design an electromagnetic stirrer by numerical simulation. The stirrer is then implemented on a model experiment. Eventually, the alloys are characterised by metallography and etching to evidence the grain structure. As expected, we obtain a substantial reduction of the grain size although, some work remains to be done to attain the final goal of even finer grains.

  19. The Abnormal Choroidal Vessels in Aged Patients

    Institute of Scientific and Technical Information of China (English)

    Shizhou Huang; Feng Wen; Dezheng Wu; Guangwei Luo; Caijiao Liu

    2002-01-01

    Background: To show the abnormal choroidal vessels in aged patients with indocyanine-green angiography (ICGA).Methods: ICGA was performed in 350 patients with TOPCON TRC-50IA fundus camera.The images were recorded and retrospectively reviewed.Results: Five aged patients out of 350 cases were found to have abnormal choroidalvessels. The incidence was 1.43%. The abnormal choroidal vessels showed round- shapet,focal enlargement, abnormal shape and entrance, satellite appearance, and vascularloops. These might be due to congenital abnormality of choroid.Conclusion: ICGA could be used to observe the abnormal choroidal vessels.

  20. Assessing China's Potential Surge on Demand for Grain Sorghum

    OpenAIRE

    Wang, Haiyan; Malaga, Jaime E.

    2015-01-01

    China is one of the world's fastest growing economies showing an impressive growth on consumption of animal protein which has resulted on a rapidly increasing derived demand for feed grains. Corn is the key feed crop for China, however, the government policies have boosted domestic corn prices above international levels. Some important facts signal that China is becoming a large market of feed grain where sorghum is a close and cheaper substitute for corn. This paper used a derived demand mod...