Effects Of Grain Research Articles

A new quantitative relation between deformation textures and corresponding mechanical properties of FCC metals

Quantitative analysis of deformation-induced textures and texture-induced mechanical properties is an important issue for optimal design and control of plastic forming of metals. Deformation-induced textures were predicted through the crystal plasticity finite-element method (CPFEM) in this study, and varying deformation modes, including uniaxial compression, uniaxial tension, simple shear, and plane-strain compression, were considered. The predicted textures were proven by experiments. Then, a theoretical model was proposed to build the quantitative relation between textures and the corresponding mechanical properties. This model takes into account the effects of grain’s orientation, grain’s interaction, and the property in the level of single grain. It captures the macroscopic anisotropy owing to textures and microscopic anisotropy owing to crystallographic structures. By applying this model, the macroscopic stress responses of grains’ aggregate with varying textures were calculated according to grain’s orientations and the intrinsic properties of the single crystal along [100] and [111] crystallographic directions. The theoretical model is proven to have high efficiency and acceptable accuracy in the prediction of texture-induced mechanical properties comparing with CPFEM model.

Theoretical breakage mechanics and experimental assessment of stresses surrounding piles penetrating into dense silica sand

This letter extends an earlier theoretical and numerical analysis that aimed to improve predictions for the large-displacement end-bearing capacity of piles in sand by considering the boundary conditions applying to steady penetration and the effects of grain crushing via breakage mechanics. The earlier work led to good agreement with the end-bearing capacities, soil displacements and evolution of grain size distributions observed in experiments of penetrating model piles. The purpose of the current paper is to complement the previous evaluation through comparisons with more recently published calibration chamber measurements of the stresses surrounding instrumented model piles penetrating into dense silica sand. Encouraging agreement is demonstrated for the radial, circumferential and vertical stress components. Scope for further improvements is also identified.

Investigation of structural and electrical properties of CuO modified SnO2 nanoparticles

Nanocrystalline SnO2 was prepared by the co-precipitation method and doped with CuO. Crystallite sizes were estimated by Scherrer formula to be of the order of 90nm and lesser. A.C. conduction behaviour of the samples has been described by the different hopping processes. From impedance analysis multi-relaxation processes in the samples are evident. Shrinkage of Cole–Cole plots with increase in temperature is also observed in our case which shows role of grain and grain boundary effects in the conduction mechanism with rise in temperature. Dielectric constant decreases with frequency but increases with rise in temperature which is governed by different components of polarizability (deformational and relaxational polarization). Dielectric constant increases with rise in temperature but at higher frequency range it takes constant value. Impedance analysis is used to explain the effects of grain and grain boundary on transport mechanism of undoped and CuO modified SnO2 nanoparticles.

Phase-field modelling of martensitic transformation: the effects of grain and twin boundaries

In this work, we present the non-linear elasto-plastic phase-field model and simulation of the martensitic transformation in a polycrystalline material including the effects of grain and twin boundaries. The phase-field microelasticity theory proposed by Khachaturyan is used to perform 2D and 3D simulations of fcc → bct martensitic transformation in a Fe–0.3%C polycrystalline alloy, incorporating the effect of both coherent and incoherent boundaries. The effect of plastic accommodation is also introduced into the model, by solving a time-dependent equation, during the solid-to-solid phase transformation. It is found that the given phase-field model, with the effect of grain boundaries, not only respects the morphological features of martensite but also conforms well with the physics of the problem. Different sets of simulations are performed to validate the model and it is concluded that the given model can correctly predict the evolution of the martensitic microstructure in a polycrystal, as opposed to previous models where the effects of grain and twin boundaries are neglected.

Effects of grain, fructose, and histidine feeding on endotoxin and oxidative stress measures in dairy heifers

Ruminal endotoxin and plasma oxidative stress biomarker concentrations were studied in dairy heifers challenged with grain, fructose, and histidine in a partial factorial study. Holstein-Friesian heifers [n=30; average body weight (BW) of 359.3±47.3kg] were randomly allocated to 5 treatment groups: (1) control (no grain); (2) grain [crushed triticale at 1.2% of BW dry matter intake (DMI)]; (3) grain (0.8% of BW DMI) + fructose (0.4% of BW DMI); (4) grain (1.2% of BW DMI) + histidine (6g/head); and (5) grain (0.8% of BW DMI) + fructose (0.4% of BW DMI) + histidine (6g/head). Rumen samples were collected by stomach tube 5, 65, 115, 165, and 215min after diet consumption and blood samples at 5 and 215min after consumption. Rumen fluid was analyzed for endotoxin concentrations. Plasma was analyzed for concentrations of the following oxidative stress biomarkers: reactive oxygen metabolites (dROM), biological antioxidant potential (BAP), advanced oxidation protein products, and ceruloplasmin, and activity of glutathione peroxidase. Dietary treatment had no effect on concentrations of endotoxin or oxidative stress biomarkers. We observed no interactions of treatment by time. Ruminal concentrations of endotoxin decreased during the sampling period from 1.12×105 ± 0.06 to 0.92×105 endotoxin units/mL ± 0.05 (5 and 215min after diet consumption, respectively). Concentrations of dROM and the oxidative stress index (dROM/BAP × 100) increased over the sampling period, from 108.7 to 123.5 Carratelli units (Carr U), and from 4.1 to 4.8, respectively. Ceruloplasmin concentrations markedly declined 5min after the consumption of diets, from 190 to 90mg/L over the 215-min sampling period. Overall, a single feeding challenge for dairy cattle with grain, fructose, and histidine, and combinations thereof, may not be sufficient to induce marked changes in endotoxin or oxidative stress biomarker concentrations.

The end-bearing capacity of piles penetrating into crushable soils

A new formula is proposed for the end-bearing capacity of piles penetrating into crushable soils. The formula is based on a breakage mechanics model that accounts for the evolution of the grain size distribution (GSD) due to grain crushing with only physically meaningful parameters. The model is integrated using the finite-element method to study the penetration problem. Predictions of GSDs surrounding piles and pile end-bearing capacities are validated against experiments. Next, a parametric study is carried out to quantify the effects of grain crushing on the bearing capacity, and then to establish the formula. The predictive capability of the new formula is highlighted against predictions by previous formulae, which highlights its superior origins.

Grain refining technique of AM60B magnesium alloy by MgCO3

The effects of grain refining parameters on microstructure of AM60B magnesium alloy with MgCO3 were investigated and then a refining technique was developed. Simultaneously, the corresponding mechanisms were discussed. The results indicate that increasing addition temperature of MgCO3 or pouring temperature is beneficial for obtaining fine grains. There is an optimal addition amount of 1.2% at the addition temperature of 790 °C. Prolonging holding time at 790 °C will increase grain size. The grain refining technique that 1.2% MgCO3 is added at 790 °C followed by holding for 10 min and pouring can decrease the grain size from 348 μm of the un-refined alloy to 69 μm. The nucleation substrates are actually the Al4C3 particles formed from reactions between the MgCO3 and alloying elements in the melt. Besides the heterogeneous nucleation regime, growth restriction of the Al4C3 particles agglomerated at growing front is the other mechanism.

Effects of grain, fructose, and histidine on ruminal pH and fermentation products during an induced subacute acidosis protocol

The effects of grain, fructose, and histidine on ruminal pH and fermentation products were studied in dairy cattle during an induced subacute acidosis protocol. Thirty Holstein heifers were randomly allocated to 5 treatment groups: (1) control (no grain); (2) grain [fed at a crushed triticale dry matter intake (DMI) of 1.2% of body weight (BW)]; (3) grain (0.8% of BW DMI)+fructose (0.4% of BW DMI); (4) grain (1.2% of BW DMI)+histidine (6g/head); and (5) grain (0.8% of BW DMI)+fructose (0.4% of BW DMI)+histidine (6g/head) in a partial factorial arrangement. Heifers were fed 1kg of grain daily with ad libitum access to ryegrass silage and alfalfa hay for 10d. Feed was withheld for 14h before challenge day, on which heifers were fed 200g of alfalfa hay and then the treatment diets immediately thereafter. Rumen samples were collected 5min after diet ingestion, 60min later, and at 3 subsequent 50-min intervals. Grain decreased ruminal pH and increased ammonia, total volatile fatty acid (VFA), acetate, butyrate, propionate, and valerate concentrations compared with controls. The addition of grain had no effect on ruminal d- and l-lactate concentrations. Fructose markedly decreased ruminal pH and markedly increased d- and l-lactate concentrations. Fructose increased total VFA and butyrate and decreased valerate concentrations. Although histidine did not have a marked effect on ruminal fermentation, increased concentrations of histamine were observed following feeding. This study demonstrates that the substitution of some grain for fructose can lower ruminal pH and increase VFA and lactate concentrations, warranting further investigation into the role of sugars on the risk of acidosis in dairy cattle.

Effect of Melt Treatment on Forming and Brazing Characteristics of 4343/3003/4343 Aluminum Clad Sheet

In this study, it was aimed to investigate the effects of grain refining of 3003 core alloy on forming and brazing characteristics of 4343/3003/4343 aluminum clad sheet. Ti inoculation level was changed up to 0.1wt% by adding Al-10Ti master alloy into 3003 aluminum melt as grain refiner. The three-layer aluminum clad sheets of 0.7 mm thickness were fabricated by hot roll bonding process. The forming and brazing characteristics were evaluated by measuring FLD (forming limit diagram), bonding strength and sagging resistance.

Influence of Homogeneous Interfaces on the Strength of 500 nm Diameter Cu Nanopillars

Interfaces play an important role in crystalline plasticity as they affect strength and often serve as obstacles to dislocation motion. Here we investigate effects of grain and nanotwin boundaries on uniaxial strength of 500 nm diameter Cu nanopillars fabricated by e-beam lithography and electroplating. Uniaxial compression experiments reveal that strength is lowered by introducing grain boundaries and significantly rises when twin boundaries are present. Weakening is likely due to the activation of grain-boundary-mediated processes, while impeding dislocation glide can be responsible for strengthening by twin boundaries.

Effects of Grain and Malt â-Glucan on Distilling Quality in a Population of Hull-less Barley

A population of barley lines, derived by mutation in the hull-less variety, Penthouse, was included in a replicated trial, along with Penthouse and the hulled malting cultivar, Optic. Samples were assessed for a range of grain quality traits, then malted, with germination for either 4 or 5 days, prior to kilning. Most lines had grain β-glucan contents lower than that of Penthouse, but there was no significant correlation between grain and malt β-glucan content. Malt β-glucan levels were indicative of differences in cell wall breakdown between 4 and 5 days germination, but negative associations with distilling parameters Extract and Alcohol Yield, were not statistically significant. It was concluded that the lines differed in the rate and extent of cell wall breakdown and that grain shape may influence modification in distal parts of the grain. However, a malting regime, optimised to suit Optic may be less suited to discriminating between hull-less lines of reasonable quality.

Dynamic Effects of Grain and Energy Prices on the Catfish Feed and Farm Sectors

This study examines the dynamic effects of grain prices and energy prices on catfish feed prices and the price of food-sized catfish at the farm level. Using the autoregressive distributed lag model and bounds testing procedure, a long-run relationship between feed and farm prices and their determinants was confirmed. Given the effect of corn and soybean meal prices on catfish feed prices, and catfish fish feed prices on farm prices, the long-run responsiveness of feed prices to a percentage increase in U.S. ethanol production is 0.325, and the responsiveness of catfish farm prices is 0.064. Although both feed and farm prices increase with ethanol production, the relatively small responsiveness of farm prices when compared with feed prices suggests that catfish farmers are worse off. Results are conditional on ethanol production causing an increase in grain prices.

Effects of Grain for Green Project on the Eco-Environmental Vulnerability of Mudanjiang Region, Heilongjiang Province

Effects of Grain for Green Project on the Eco-Environmental Vulnerability of Mudanjiang Region, Heilongjiang Province

Scale dependent inference in landscape genetics

Ecological relationships between patterns and processes are highly scale dependent. This paper reports the first formal exploration of how changing scale of research away from the scale of the processes governing gene flow affects the results of landscape genetic analysis. We used an individual-based, spatially explicit simulation model to generate patterns of genetic similarity among organisms across a complex landscape that would result given a stipulated landscape resistance model. We then evaluated how changes to the grain, extent, and thematic resolution of that landscape model affect the nature and strength of observed landscape genetic pattern–process relationships. We evaluated three attributes of scale including thematic resolution, pixel size, and focal window size. We observed large effects of changing thematic resolution of analysis from the stipulated continuously scaled resistance process to a number of categorical reclassifications. Grain and window size have smaller but statistically significant effects on landscape genetic analyses. Importantly, power in landscape genetics increases as grain of analysis becomes finer. The analysis failed to identify the operative grain governing the process, with the general pattern of stronger apparent relationship with finer grain, even at grains finer than the governing process. The results suggest that correct specification of the thematic resolution of landscape resistance models dominates effects of grain and extent. This emphasizes the importance of evaluating a range of biologically realistic resistance hypotheses in studies to associate landscape patterns to gene flow processes.

Effects of grain and oilseed prices on the costs of US poultry production

In 2002, the US government encouraged the production of ethanol and other biofuels through a combination of tax benefits and direct subsidies. Most of the ethanol produced in the United States comes from corn, the most abundant crop available. In 2002, 11% of available US corn was used for ethanol production. By 2008, approximately 30% of the US corn crop was used for ethanol production. The increased demand for corn supplies as a result of the diversion of significant amounts of corn for biofuel production in the United States, combined with increased world demands for feed grains, have resulted in unprecedented feed prices for livestock and poultry. Feed ingredient costs as a percentage of live production costs have increased from 51.8% in 2001 to 68.7% in 2008. Live production costs for broilers increased from $0.25 per pound of live weight in September 2006 to $0.45 in 2008. Similarly, live production costs for turkey meat increased from $0.35 per pound in 2006 to $0.58 in 2008, whereas the live production costs for a dozen eggs increased from $0.34 to $0.56. The increased costs of feed ingredients in the United States have resulted in $9.36 billion in cumulative additional costs to the poultry industries since 2006. Despite increases in land planted to corn and soybeans, the demand for feed grains has outpaced the supply. These factors will likely continue to put pressure on poultry producers in the United States as they seek to regain profitability.

The Effects of Grain-boundary Orientations on Failure Behavior in F.C.C. Polycrystalline Systems

A multiple-slip rate-dependent crystalline constitutive formulation that is coupled to the evolutionary equations of mobile and immobile dislocation densities is used with specialized finite-element methodologies to obtain a detailed microstructural prediction of the inelastic deformation and interrelated physical mechanisms that affect different failure modes in f.c.c. crystalline materials. The effects of grain and grain-boundary (GB) orientations, grain shape and size, GB strength, and mechanical properties on the inelastic finite deformation and failure mode mechanisms in polycrystalline aggregates with Σ3 and Σ17b GBs have been investigated. Results from this study are consistent with experimental observations that microstructures with desired material properties, such as resistivity to crack nucleation, can be potentially achieved by the control of grain aggregate size and CSL GB orientations. Furthermore, it is also shown that transgranular failure modes can occur in aggregates with a high frequency of Σ3 GBs, whereas intergranular fracture modes can occur with a high frequency of Σ17b GBs.

Effects of grain, grain boundary, and dc electric field on giant dielectric response in high purity CuO ceramics

Giant dielectric constant ε′ of ∼(2.8–3.7)×104 was observed in high purity CuO (99.999%) ceramics with grain sizes of 4.57±1.71 and 9.57±3.01 μm. The ε′ and Ea increase with an increase in grain size due to the different electrical properties in the grains. The high dielectric response observed in the CuO ceramics can be described by the internal barrier layer capacitance model. The resistance of grain boundaries (Rgb) and the dielectric constant of the CuO samples decrease with increasing dc bias due to the decrease in grain boundaries capacitance, whereas the resistance of grains (Rg) remains constant.

Effect of grain refining on primary α phase in semi-solid A356 alloy prepared by low superheat pouring and slight electromagnetic stirring

The semi-solid slurry of A356 alloy, which is grain-refined by Al-Ti-B master alloy, is prepared by low superheat pouring and slight electromagnetic stirring. The effects of grain refining on the morphology and the grain size of the primary α phase in the slurry manufactured are researched. The results indicate that the slurry with particle-like and rosette-like primary α phases can be prepared by low superheat pouring and slight electromagnetic stirring from liquid A356 alloy grain-refined, in which the pouring temperature can be suitably raised. Compared with the A356 samples without grain refining, the grain size and particle morphology of primary α phase as well as the distribution of the grain with particle-like or rosette-like along radial in the ingot in A356 are markedly improved by grain refining. KEY WORDS Semi-solid; Grain-refined; Low superheat pouring; Slight electromagnetic stirring; A356 alloy; Al-Ti-B

Effect of Grain Refinement on Structure Evolution, “Floating” Grains, and Centerline Macrosegregation in Direct-Chill Cast AA2024 Alloy Billets

Direct-chill (DC) cast billets 192 mm in diameter of an Al-Cu-Mg alloy were examined in detail with the aim to reveal the effects of grain refining (GR) and casting speed on structure, “floating” grains, and centerline macrosegregation. Experimental results show that grain size and dendrite arm spacing (DAS) tend to coarsen toward the billet center with a local refinement DAS in the center. In GR billets, grain size does not change much with the cooling rate, casting speed, and grain refiner amount. Coarse-DAS (floating) grains are observed around the billet axis regardless of GR and the amount of Ti, though their amount is significantly higher in GR billets. Macrosegregation profiles show a negligible influence of GR, while the effect of casting speed is large. The concept of solute-depleted floating grains contributing to the centerline macrosegregation is substantiated by microsegregation measurements, which show that, independent of GR, coarse dendrite branches have a depleted concentration plateau in contrast to the fine dendrite arms.

Effects of washing procedure, particle size and dilution on the distribution between non‐washable, insoluble washable and soluble washable fractions in concentrate ingredients

AbstractThe effects of washing procedure, particle size and dilution on the distribution of non‐washable (NWF), insoluble washable (ISWF) and soluble washable (SWF) fractions were studied. The effects of three washing procedures (Yang (Y), Melin (M) and in situ (IS)) on the size of NWF, ISWF and SWF in six concentrate ingredients (maize, barley, milo, peas, lupins and faba beans), ground at two different particle sizes, were compared. Method M was further developed (method SM) by reducing the dilution ratio; its effect on NWF, ISWF and SWF was compared. A new washing method was developed (method AA) which involved continuous washing of nylon bags in a centrifuge beaker; its effect on NWF, ISWF and SWF at different dilutions with water was compared with the IS, M, SM and Y methods. The effects of different dilutions on SWF and soluble true protein (STP) in six concentrate ingredients were studied. The effects of grain, washing method and particle size on the size of NWF and ISWF were significant, with significant interactions between grain and particle size, grain and washing method, particle size and washing method, but no interaction between grain type, washing method and particle size. In method Y the size of NWF was smaller than in the other methods. The results showed that, except in lupins, NWF in grains was significantly higher than in legume seeds. Increasing the particle size significantly increased NWF, whereas ISWF was decreased. The size of SWF in legume seeds was higher than in the grains. Increasing the dilution, increased STP in legume seeds, but not in grains. Copyright © 2007 Society of Chemical Industry