Solute and Second Phase Evolution during Industrial Processing of AA3103

2007 ◽  
Vol 539-543 ◽  
pp. 281-286 ◽  
Author(s):  
A. Miroux ◽  
Zacharias J. Lok ◽  
Knut Marthinsen ◽  
Sybrand van der Zwaag
Keyword(s):  
Hot Rolling ◽  
Particle Growth ◽  
Phase Evolution ◽  
Constituent Particle ◽  
Precipitation Process ◽  
Second Phase ◽  
Solute Content ◽  
Industrial Processing ◽  
Solute Depletion ◽  
Second Phases

The complete evolution of solute content and second phases during full-scale industrial processing of AA3103 sheets has been measured. During pre-heating, dispersoids, which appear as plates or small polyhedra grow and the Mn solute content decreases. During subsequent breakdown rolling the dispersoid number-density increases significantly. The measured decrease of solute Mn after hot rolling and coil cooling is attributed to constituent particle growth, whereas the solute depletion during the final back-annealing is mainly caused by the growth of the dispersoids. These observations are compared to the predictions obtained by a semi-physical model for precipitation. Although simulations have been performed without any retro-fitting, for hot rolling the results compare quantitatively well with experiment, while for coil cooling and back annealing the modelled Mn solute depletion is underestimated. The precipitation process is found to be very sensitive to the microstructure, which illustrates the importance of coupling precipitation models with work hardening and softening models to obtain reliable predictions.

Solute and Second Phase Evolution during Industrial Processing of AA3103

2007 ◽  
pp. 281-286
Author(s):  
A. Miroux ◽  
Zacharias J. Lok ◽  
Knut Marthinsen ◽  
Sybrand van der Zwaag
Keyword(s):  
Phase Evolution ◽  
Second Phase ◽  
Industrial Processing

Structure of second phases in TiAl alloys containing Cr and B

1991 ◽  
Vol 49 ◽  
pp. 576-577
Author(s):  
Ernest L. Hall ◽  
Shyh-Chin Huang
Keyword(s):  
Grain Size ◽  
Second Phase ◽  
Structure And Properties ◽  
Tial Alloys ◽  
Second Phases ◽  
Interstitial Elements

Addition of interstitial elements to γ-TiAl alloys is currently being explored as a method for improving the properties of these alloys. Previous work in which a number of interstitial elements were studied showed that boron was particularly effective in refining the grain size in castings, and led to enhanced strength while maintaining reasonable ductility. Other investigators have shown that B in γ-TiAl alloys tends to promote the formation of TiB2 as a second phase. In this study, the microstructure of Bcontaining TiAl alloys was examined in detail in order to describe the mechanism by which B alters the structure and properties of these alloys.

Structural Changes in a 9%Cr Creep Resistant Steel during Creep Test

2012 ◽  
Vol 715-716 ◽  
pp. 895-900
Author(s):  
Valeriy Dudko ◽  
Andrey Belyakov ◽  
Vladimir Skorobogatykh ◽  
Izabella Schenkova ◽  
Rustam Kaibyshev
Keyword(s):  
Structural Changes ◽  
Subgrain Size ◽  
Large Strain ◽  
Particle Growth ◽  
Second Phase ◽  
Second Phase Particles ◽  
Creep Rupture Test ◽  
Lath Structure ◽  
Creep Regime ◽  
Effective Stabilization

Structural changes in a 9%Cr martensitic steel after 1%, 4% creep and creep rupture test at 650°C and stress of 118 MPa were examined. Heat treatment provided the formation of tempered martensite lath structure (TMLS) in the steel. The precipitations of second phase particles along block and lath boundaries provide effective stabilization of the TMSL under annealing/aging condition. This structure hardly changed under creep conditions in grip portion of crept sample. Significant coarsening of both the second phase particles and the martensite laths takes place in neck portion. In addition, the latter ones lose their original morphology and are replaced by large strain-induced subgrains. It should be noted that the increase of subgrain size is in almost direct proportion to the particle growth during the creep to 4% strain. The rapid growth of martesite laths followed by their evolution to deformation subgrains takes place within the tertiary creep regime.

Dynamics of glucose-induced insulin secretion in normal human islets

2015 ◽  
Vol 309 (7) ◽  
pp. E640-E650 ◽  
Author(s):  
Jean-Claude Henquin ◽  
Denis Dufrane ◽  
Julie Kerr-Conte ◽  
Myriam Nenquin
Keyword(s):  
Insulin Secretion ◽  
Stimulation Index ◽  
Human Islets ◽  
Diabetic Patients ◽  
Second Phase ◽  
Biphasic Insulin ◽  
Biphasic Insulin Secretion ◽  
Normal Human ◽  
Second Phases

The biphasic pattern of glucose-induced insulin secretion is altered in type 2 diabetes. Impairment of the first phase is an early sign of β-cell dysfunction, but the underlying mechanisms are still unknown. Their identification through in vitro comparisons of islets from diabetic and control subjects requires characterization and quantification of the dynamics of insulin secretion by normal islets. When perifused normal human islets were stimulated with 15 mmol/l glucose (G15), the proinsulin/insulin ratio in secretory products rapidly and reversibly decreased (∼50%) and did not reaugment with time. Switching from prestimulatory G3 to G6–G30 induced biphasic insulin secretion with flat but sustained (2 h) second phases. Stimulation index reached 6.7- and 3.6-fold for the first and second phases induced by G10. Concentration dependency was similar for both phases, with half-maximal and maximal responses at G6.5 and G15, respectively. First-phase response to G15–G30 was diminished by short (30–60 min) prestimulation in G6 (vs. G3) and abolished by prestimulation in G8, whereas the second phase was unaffected. After 1–2 days of culture in G8 (instead of G5), islets were virtually unresponsive to G15. In both settings, a brief return to G3–G5 or transient omission of CaCl2 restored biphasic insulin secretion. Strikingly, tolbutamide and arginine evoked immediate insulin secretion in islets refractory to glucose. In conclusion, we quantitatively characterized the dynamics of glucose-induced insulin secretion in normal human islets and showed that slight elevation of prestimulatory glucose reversibly impairs the first phase, which supports the view that the similar impairment in type 2 diabetic patients might partially be a secondary phenomenon.

Internal Stresses in Nanocrystalline Nickel and Nickel-Iron Alloys

2012 ◽  
Vol 706-709 ◽  
pp. 1607-1611 ◽  
Author(s):  
J.D. Giallonardo ◽  
Uwe Erb ◽  
G. Palumbo ◽  
G.A. Botton ◽  
C. Andrei
Keyword(s):  
Grain Size ◽  
Internal Stress ◽  
Structural Difference ◽  
Intrinsic Stress ◽  
Internal Stresses ◽  
Second Phase ◽  
Nickel Iron ◽  
Second Phase Particles ◽  
Second Phases ◽  
Rule Out

Nanocrystalline metals are often produced in a state of stress which can adversely affect certain properties, e.g. corrosion resistance, wear, fatigue strength, etc. This stress is referred to as internal or “intrinsic” stress since it is not directly caused by applied loads. The structural causes of these stresses in nanocrystalline materials are not fully understood and are therefore an area of particular interest. The internal stresses of nanocrystalline Ni and Ni-16wt%Fe were measured and found to increase with the addition of iron. Characterization using HR-TEM revealed no signs of porosity, second phase particles, or a high density of dislocations. Both materials possessed well defined high-angle grain boundaries. The main structural difference between the two materials was found to be grain size and correspondingly, a decrease in grain size resulted in an increase in internal stress which supports the applicability of the coalescence theory. The current study also provides evidence to rule out the effect of voids (or porosity), dislocations, and second phases as possible causes of internal stress.

scholarly journals The effect of soybean formula and formula 100 supplementation on the growth of preschool children

2016 ◽  
Vol 45 (6) ◽  
pp. 256
Author(s):  
M Mexitalia ◽  
Yohanes Tri Nugroho ◽  
J C Susanto
Keyword(s):  
Preschool Children ◽  
Body Height ◽  
High Energy ◽  
Second Phase ◽  
Z Score ◽  
Health Food ◽  
Alternative Health ◽  
Second Phases ◽  
The Difference ◽  
Weight For Age

Background Preschool children are vulnerable in growth. Soy-bean formula (SF) and formula-100 (F100) are supplementary foodswhich contain of high energy and are available at low price; how-ever, they are not widely used for preschool children.Objectives To investigate the effect of SF compared to F100 onthe growth of preschool children.Methods A cross-over trial was conducted on 96 preschool chil-dren aged 4-7 years. Subjects were randomly divided into 2 groupswhich received 200 ml soybean formula (n=49) or F100 (n=47) for1 month and crossed-over after a six-week wash-out period. Bodyweight was measured weekly. Body height and food analysis by 3-day food recall were measured at the beginning and the end of thestudy. The criteria of the acceptability of the formula was eithergood or poor.Results Supplementation with SF as well as F100 induced catchup growth as shown by the increase of Δz-score. There were nosignificant difference of Δ weight for age z-score, Δ height for agez-score, and Δ weight for height z score between groups duringthe first and second phases of the trial. The acceptability of F100was significantly better than that of SF at the beginning; neverthe-less, the difference was not significant at the second phase trial.Conclusions Soybean formula and F100 given for a one monthperiod can induce catch-up growth in preschool children. Soybeanformula as an alternative health food can be accepted by preschoolchildren

Numerical simulation of the Late Jurassic closure of the Vardar Tethys

2021 ◽  
Author(s):  
Nikola Stanković ◽  
Vesna Cvetkov ◽  
Vladica Cvetković
Keyword(s):  
Boundary Conditions ◽  
Numerical Simulations ◽  
Stokes Equations ◽  
Numerical Study ◽  
Phase Evolution ◽  
Staggered Grid ◽  
Second Phase ◽  
Weak Zone ◽  
Ongoing Research ◽  
Magmatic Complex

<p>We report updated results of our ongoing research on constraining geodynamic conditions associated with the final closure of the Vardar branch of the Tethys Ocean by means of application of numerical simulations (previous interim results reported in EGU2020-5919).</p><p>The aim of our numerical study is to test the hypothesis that a single eastward subduction in the Jurassic is a valid explanation for the occurrence of three major, presently observed geological entities that are left behind after the closure of the Vardar Tethys. These include: ophiolite-like igneous rocks of the Sava-Vardar zone and presumably subduction related Timok Magmatic Complex, both Late Cretaceous in age as well as Jurassic ophiolites obducted onto the Adriatic margin. In our simulations we initiate an intraoceanic subduction in the Early/Middle Jurassic, which eventually transitions into an oceanic closure and subsequent continental collision processes.</p><p>In the scope of our study numerical simulations are performed by solving a set of partial differential equations: the continuity equation, the Navier-Stokes equations and the temperature equation. To this end we used I2VIS thermo-mechanical code which utilizes marker in cell approach with finite difference discretization of equations on a staggered grid [Gerya et al., 2000; Gerya&Yuen, 2003].</p><p>The 2D model consists of two continental plates separated by two oceanic slabs connected at a mid-oceanic ridge. Intraoceanic subduction is initiated along the ridge by assigning a weak zone beneath the ridge. Time-dependent boundary conditions for velocity are imposed on the simulation in order to model a transient spreading period. The change of sign in plate velocities is found to be useful for both obtaining obduction / ophiolite emplacement [Duretz et al., 2016] and causing back-arc extension. Changes in velocities are linear in time. Simulations follow a three-phase evolution of velocity boundary conditions consisting of two convergent phases separated by a single divergent phase where spreading regime is dominant. Effect of duration and magnitude of the second phase on model evolution is also explored.</p><p>Our so far obtained simulations were able to reproduce the westward obduction and certain extension processes along the active (European) margin, which match the existing geological relationships. However, the simulations involve an unreasonably short geodynamic event (cca 15-20 My) and we are working on solving this problem with new simulations. </p>

Effect of galanin on glucose-, arginine-, or potassium-stimulated insulin release

1989 ◽  
Vol 256 (5) ◽  
pp. E619-E623
Author(s):  
T. Yoshimura ◽  
J. Ishizuka ◽  
G. H. Greeley ◽  
J. C. Thompson
Keyword(s):  
Insulin Release ◽  
High Glucose ◽  
Second Phase ◽  
Dependent Manner ◽  
Perfused Pancreas ◽  
Isolated Perfused Pancreas ◽  
Second Phases ◽  
High Concentrations ◽  
Dose Dependent ◽  
Stimulation Of

We have examined the effect of galanin infusion on glucose-stimulated release of insulin from the isolated perfused pancreas of the rat to better characterize the effect of galanin on the first and second phases of insulin release. The effects of galanin on insulin release stimulated by L-arginine or high concentrations of potassium were also examined. When perfusion of galanin was started 4 min before the start of perfusion of high glucose (16.7 mM), galanin (10(-8)-10(-11) M) inhibited both the first and second phases of insulin release in a dose-dependent manner. When perfusion of galanin (10(-8) or 10(-9) M) was started simultaneously with high glucose (16.7 mM), only the second phase of insulin release was suppressed (P less than 0.05). Galanin (10(-9) M) failed to inhibit insulin release stimulated by L-arginine (10 and 5 mM) or potassium (25 and 20 mM). These findings suggest that the inhibitory action of galanin on glucose-stimulated insulin release is exerted on early intracellular events that occur during the stimulation of insulin release and that are common to both phases. Because galanin does not inhibit insulin release stimulated by L-arginine or potassium, galanin may inhibit glucose-stimulated closure of potassium channels.

scholarly journals Effect of Zn Content on the Microstructure and Mechanical Properties of Mg–Al–Sn–Mn Alloys

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3102
Author(s):  
Tianshuo Zhao ◽  
Yaobo Hu ◽  
Fusheng Pan ◽  
Bing He ◽  
Maosheng Guan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Dendritic Structure ◽  
Second Phase ◽  
Microstructure And Mechanical Properties ◽  
Zn Content ◽  
Dislocation Movement ◽  
Cast Alloys ◽  
Complete Recrystallization ◽  
Second Phases

High performance Mg–6Al–3Sn–0.25Mn–xZn alloys (x = 0, 0.5, 1.0, 1.5, and 2.0 wt %) without rare earth were designed. The effects of different Zn contents on the microstructure and mechanical properties were systematically investigated. The addition of Zn obviously refines the as-cast alloys dendritic structure because of the increase in the number in the second phase. For the as-extruded alloys, an appropriate amount of Zn promotes complete recrystallization, thus increasing the grain size. As the Zn content increases, the texture gradually evolves into a typical strong basal texture, which means that the basal slip is difficult to initiate. Meanwhile, the addition of Zn promotes the precipitation of small-sized second phases, which can hinder the dislocation movement. The combination of texture strengthening and precipitation strengthening is the main reason for the improvement of alloys’ strength.

Composition-induced microstructures in rhombohedral carbonates

1987 ◽  
Vol 51 (359) ◽  
pp. 71-86 ◽  
Author(s):  
D. J. Barber ◽  
M. Riaz Khan
Keyword(s):  
Electron Diffraction ◽  
Crystallographic Orientation ◽  
Solid Solubility ◽  
Single Phase ◽  
Crystal Defects ◽  
Second Phase ◽  
Two Phase ◽  
Diffraction Contrast ◽  
Second Phases ◽  
Metallic Impurities

AbstractRecent TEM observations of two-phase microstructures and associated crystal defects in selected, rare dolomites have been extended to calcite-structured (R3̄c) carbonates and to other natural and synthetic carbonates that crystallize with the dolomite (R3̄) structure. The samples included siderites (FeCO3), smithsonites (ZnCO3), ankerites (Ca[Mg,Fe](CO3)2), and kutnahorites (Ca[Mn,Fe](CO3)2).TEM methods show that the forms of second phases which result from the presence of common, divalent, metallic impurities are morphologically similar in R3̄c and R3̄ carbonates and occur more widely than hitherto realized. The most common form consists of thin ribbons of second phase which are coherent with and have the same crystallographic orientation as the host carbonate. Another form of microstructure, manifest as modulations in diffraction contrast, appears to be associated with incipient breakdown of single-phase carbonate. The results of extensive TEM/EDS microanalyses show that in siderite and ankerite the formation of ribbons is promoted by Ca impurity or Ca excess (with respect to R3̄c stoichiometry). In smithsonite, Cu and Ca impurities can play similar roles in relation to modulated microstructures. In kutnahorites, the perfection of grains and the absence of second-phase effects is strongly dependent on the ratio of Fe to Mn but is also affected by Ca in excess of the stoichiometric requirement. Electron diffraction results from several of the minerals show c-type spots, which can be interpreted as indicating ordering within basal layers of cations.The results show that, by correlating analytical TEM data with the study of second phases and incipient two-phase microstructures, it should be possible to determine the limits of solid solubility in carbonate systems.

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