In a previous study, multiple yield components and spike characteristics were associated with the Q gene interval in the bread wheat ‘Forno’ × European spelt ‘Oberkulmer’ recombinant inbred line population. Here we reported that this interval was also associated with grain yield, grains m -2 , grain morphology and spike dry weight at anthesis. To clarify the roles of Q in agronomic trait performance, a functional marker for the Q gene was developed. Analysis of allelic effects showed that the bread wheat Q allele conferred free-threshing habit, soft glumes, and short and compact spikes compared with q. In addition, the Q allele contributed to higher grain yield, more grains m –2 and higher thousand grain weight, whereas q contributed to more grains per spike/spikelet likely resulting from increased preanthesis spike growth. For grain morphology, the Q allele was associated with reduced ratio of grain length to height, indicating a rounder grain. These results are supported by analysis of four Q mutant lines in the Chinese Spring background. Therefore, the transition from q to Q during wheat domestication had profound effects on grain yield and grain shape evolution as well, being a consequence of pleiotropy.
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Both the grain size and the SDAS are aﬀected by alloy composition and cooling rate through CU parameters. The major diﬀerence is that the grain size is aﬀected by the constitutional conditions as solidiﬁcation begins, whilst the SDAS is more aﬀected by the CU generated by the liquid remaining near the end of solidiﬁcation. Hence solute additions that have a large eﬀect on the grain size, such as Ti, do not necessarily have a signiﬁcant eﬀect on the SDAS. Increasing the cooling rate decreases both the SDAS and the grain size, although it has a greater eﬀect on the SDAS. The diﬀerent eﬀects of grain reﬁner additions and cooling rate on grain size and SDAS means that a wide variety of grain morphologies can be generated. It is suggested that the ratio of grain size to SDAS can be used to deﬁne the grain morphology. At ratios less than two the grain morphology is spherical or globular, between 2 and 4 it is rosette-like or cellular and above 4 it is equiaxed dendritic. Understanding these relationships may assist with engineering problems such as optimization of microstructure during rheocasting and the understanding of hot tearing.
specimens were produced through rolling reductions up to 99% of an as-cast ingot and a subsequent 1100 or 590 °C anneal. The high temperature anneal produced a recrystallized grain structure having a wide variation in crystal orientation as determined by orientation imaging microscopy. This recrystallized specimen exhibited a net magnetostriction of ⬃ 170 ppm in the rolling direction and was well correlated with the finite element model result. The low temperature annealed specimen possessed fine elongated grains having dispersed 兵 001 其具 110 典 and 兵 111 其具 211 典 textures. Net magnetostrictions of 30 and 37 ppm were measured in the rolling direction and 45° off the rolling direction, respectively. The low magnetostriction value in the 45° direction disagrees substantially with the finite element solution of 157 ppm and suggests that unknown factors are dominating the response. © 2003 American Institute of Physics. 关 DOI: 10.1063/1.1540062 兴
The roasting of coffee or coffee substitutes, including cereal grains, provides useful information for under- standing the effect of heat on wheat grain. Coffee bean composition is broadly similar to that of cereals, though there is a higher percentage of lipids, and chlorogenic acid is also present. Coffee beans are typically roasted at 200 – 240°C in open, aerobic con- ditions for periods of c.3 – 12minutes (Illy 2002). During roasting, the beans pass through two ‘ cracking ’ stages of extreme morphological change (marked by audible ‘ cracks ’ ) at c.190 and 224°C, which are thought to be caused by processes of dehydration and pyrolysis, respectively. The onset of pyrolysis, causing the release of bound water and carbon dioxide, continues for up to c.17.5 minutes and results in a reduction in grain mass (Rodrigues 2003). Changes in bean shape and colour occur within seconds of the roasting tem- perature being reached (Fischer and Cammenga 2001), producing a wide range of surface colours from dark brown to black depending on the precise tem- perature and duration of roasting. Mass lost decreases consistently with both temperature and time and, after the roasting period, averages 17.6% (Bekedam et al. 2008; Geiger et al. 2005; Redgwell et al. 2002), exceeding the typical water content estimates for green coffee beans, and presumably re ﬂ ecting the release of volatiles. Polysaccharides within the beans are degraded as the cells expand under pressure from the release of steam and carbon dioxide (Redgwell et al. 2002); at 240°C, a 35–40% decrease in poly- saccharides can be seen after 7–8.5minutes (Bekedam et al. 2008; Geiger et al. 2005; Redgwell et al. 2002).
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Grain morphology is the inherited characters of a variety (Wan et al., 2008; Bai et al., 2010). Different morphology (Table 4) was shown in the rice cultivars although they are given a similar name by farmers. The rice cultivars were differentiated into four physical grain morphology groups, i.e. medium-medium grain, medium- slender grain, long-slender grain and short-medium grain. Medium grain length and shape was the dominance group among the cultivars. Wide range of thousand kernels weights was shown with the values ranging from 10.08 g to 21.33 g. Tuan and Pulut with genotypic similarity of 85.7% were found to be morphological distinct from the remaining rice cultivars.
The suitability of silica sand deposits of Gada and Muvur in Mubi North Local Government Area of Adamawa State, Nigeria for commercial glass production was assessed based on the chemical and physical properties of the silica sand samples collected along the river sides. The test was carried out at National Metallurgical Development Centre (NMDC) Jos. Chemical analysis was carried out using x-ray florescence spectrometer (XRFS) and the physical properties such as the particle size, grain morphology and specific gravity examinations were carried out using mechanical shaker (sieving method), electronic microscope to reveal the shape of the samples and the specific gravity testing machine respectively. The results obtained were assessed and compared with the standard requirements for glass making. Gada had the highest percentage of silica content of 81.00% and Muvur had the lowest percentage of silica content of 79.40%, but all samples are within the acceptable limits for glass making. The iron oxide content in all the samples was found to be high, with highest value of 1.33% for Muvur and lowest value of 1.28% for Gada. However, the iron content for all the samples was above 1% thereby limiting the range of applications to coloured and amber glass manufacturing. The physical properties that is, the grain morphology which was found to be angular with specific gravity of 2.50 for both the samples were found to satisfy the standard requirements for glass making.
Melt-spun, rapid solidiﬁed Fe-Ga ribbon sample exhibited large magnetostriction and good ductility as compared with conventional bulk sample. But the origin was not clear yet. In order to investigate the occurrence of large magnetostriction in Fe-Ga ribbon sample, the correlation between magnetostriction and the crystal grain morphology was inspected in detail by SEM/EBSP method for Fe-15 at%Ga alloy. In comparison with as-spun ribbon sample, short-time (0.5 h) heat treated ribbon had stronger  oriented texture and exhibited larger magnetostriction of 140 ppm (10 6 ) at 800 kA/m. These phenomena suggest that such a large magnetostriction is caused by the release of
Since calibration is performed on a single realization of the mesoscopic structure, it is important to validate that the variation of the calibrated EOS among different realizations is low. The sensitivity to the randomness of the grain morphology is examined on 9 realizations of grain ensembles containing 80 grains. The pressure- density curves of all simulations along with the deviation from the average EOS are presented in Fig. 6. The variation in pressure is up to 5%. Hence, the accuracy of the calibrated EOS can be roughly taken as 5%.
Microstructural variations affect deformation response of materials and it is not presented in most of plastic flow prediction models. This work presents a unified description for the deformation response of Ti-6Al-4V (Ti-64) that successfully captures the differences in strength between microstructures produced by conventional cast & wrought routes (C&W) and those obtained by Additive Manufacturing (AM), under various deformation conditions. In the developed model the grain morphology, grain size, phase volume fractions and phase chemical compositions have been linked to the mechanical properties of the studied Ti-64 alloys to predict the effect of processing routes on deformation behaviour of the materials. The model performance has been tested on seven different microstructures from C&W to AM processing routs. It has been found that altering the microstructure greatly affects the yield strength of the tested materials. Additionally, the strength of Ti-64 was found to be mostly affected by the relative volume fraction of , and ’, and their respective morphology. The results showed that the model not only successfully predicts the strength of martensitic structures generated through AM but also those obtained by quenching in conventional C&W processing. The findings from this study also suggest that the model could be extended to other titanium alloys within the + family .
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thick film depends on the shape and size of the grains. It is well known that as polarization increases dielectric constant also increases, and polarization is affected by structural homogeneity, stoichiometry, density, grain size and porosity . Due to increase in copper content the structural homogeneity decreases which may cause a slight increase in polarization.
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The effect of different deposition regimes (constant and reversing currents, constant and pulsating overpotential), on the powdered and dendritic silver electrodeposits morphology were investigated. The morphology of electrodeposited silver powder was studied utilizing a scanning electron microscope. The results obtained in constant regimes were compared with those obtained in pulsating and reversing regimes. The size of dendrites decreased strongly with increased overpotential or current. It was also shown that the agglomeration of silver dendrites in spongy-like agglomerates was strongly decreased by pulsating overpotential electrodeposition or reversing current. The possibility of obtaininig powder particles, with different properties, depending on conditions of electrolysis was demonstrated.
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Table 2 presented above shows the result of the KNN classification of the three rice grain varieties namely: Glutinous, Maharlika and Sinandomeng rice. The proposed KNN classifier have a good accuracy percentage in classifying the glutinous rice variety, for k=1 to k=10 the range of error is from 10 to 13 errors out of 60 samples which results for obtaining 83.33% rate. The morphological features of the maharlika and sinandomeng are overlapping thus they are very close neighbors as shown in Table 2. Given with enough and good accuracy rate, the results show that there is a high probability in classifying rice grain variety using KNN classifier specially when using a K of 1 and 2. The k=1 yields the highest accuracy rate on the right classification of the rice grains aside from k=2 and k=4. Thus, the features of a single grain compare to its neighbor will yield the same features of the same variety together with when the value of k is equal to 1.
Although great progress has been made, it is worth noting that the excessive addition of saccharin is detrimental to Ni–Co coatings. Increasing saccharin concentration leads to a rise in sulfur and carbon impurities, resulting in poorer ductility and tensile strength . Moreover, it is necessary to further refine the grain size of Ni–Co coatings. To the best of our knowledge, a supergravity field has not been applied to improve the performance of electrodeposited Ni–Co coatings. Atobe first reported the effects of supergravity on the polymerization rate of polyaniline and on the performance of polymeric aromatic compounds formed by electrodeposition . Eftekhai improved the properties of soft magnetic materials by employing an external centrifugal force during the deposition process . Using supergravity, Liu prepared flocky MnO 2 /carbon nanotube coatings that proved extremely
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Electrodeposition of FeCo alloy films is one of the most popular fabrication processes for its low cost and simple, flexible operation, inexpensive apparatus and easy reliable control by changing the parameters in the whole electrodeposition process although stable plating baths are needed for commercial processing. In electrodeposition, the growth mechanism, morphology, and microstructural properties of the film depend on electrodeposition conditions such as electrolyte pH, temperature, deposition potential and electrolyte composition. The variations of these parameters have been shown to affect the growth mechanism, morphology, microstructure, and magnetic properties of the deposited films [4–14]. By adjusting these deposition parameters, it can be possible to control and optimize the structural, mechanical, magnetic and magneto-transport properties of electrodeposited films. Generally, the aim of the work is to clarify the effect of deposition conditions on electrodeposited FeCo films. It is well established that the variation of current density produces a variation in grain size, due to the occurrence of hydrogen evolution at the cathode interface. A variation of this hydrogen evolution reaction that occurred at the cathode surface caused the modification of the growth interface and consequently the change of the surface energy and growth process which in order conducted the formation of larger grain size [15-19]. Also, the bath temperature in electrodeposition solutions is extremely important due to their influence on the nucleation-growth and microstructure of the resulting deposits. It is well known that bath temperature affect the physical and mechanical properties of electrodeposited thin films such as surface roughness, grain size, texture, brightness, internal stress, current efficiency, and even chemical composition [18-24]. In addition, it was observed that the solution pH changes the condition of metal ions, which usually plays a key role to control the film properties [23-28]. A modification of bath pH can also affect the crystallite size and consequently the magnetic properties such as magnetoresistance of some materials obtained by electrodeposition [23- 28]. Consequently, the electrolyte pH is one of critical parameters to achieve the desired structural and functional properties.
Surface morphology of the thin film coatings was inspected using a FESEM (Zeiss Neon 40EsB). Sample was mounted on the substrate holder using carbon tape and sputter-coated with platinum to reduce charging effects prior to analysis. FESEM images were obtained using InLens detectors at various magnifications at 5 kV. Solar absorptance values were established using the AM1.5 solar spectrum standard via hemispherical reflectance recorded from 300 to 2700 nm via UV-Vis-NIR Jasco V-670 double beam spectrophotometer with 60 mm integrating sphere.
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The current approaches used to produce the NC-materials can be roughly classified into two groups: (1) powder metallurgy and (2) severe plastic deformation (SPD) e.g. via high-pressure torsion (HPT). Other SPD methods including equal channel angular extrusion (ECAE) or “abc” deformation enable to obtain bulk material but a final grain size is typically significantly large than 100 nm. At the same time, dimensions of HPT-samples are limited to the size of a small coin. For testing of such miniature samples, special micromechanical testing machines were developed. For the typical nanostructured HPT sample with a thickness of ~0.1 mm, about 2000 grains with the average size of 50 nm may fit the thickness of the sample. Furthermore the microstructure after HPT is often heterogeneous with a broad grain size distribution. Mechanical behavior of such samples will differ from the samples with homogeneous structure. The samples produced by compacting of nanopowders can be essentially larger , their microstructures are more homogeneous, and residual porosity may be close to zero. However, contamination by impurities and oxides during the sample production may influence the mechanical behavior. Thus, production of bulk fully dense samples with grain sizes less than 100 nm and homogeneous microstructure using processing way that eliminates contamination of material by impurities and oxides is of a great importance for understanding of deformation behaviour of nanomaterials.
the magnetic properties of nanocomposite materials depend strongly on the grain size, structure and morphology of phases, distribution of the magnetically hard and soft phases, and impurity. Numerous efforts have recently been made into the fabrication of nanocomposite particles to enhance exchange coupling interaction by controlling the particle size and distribution particles. A mong the hard materials (NdFeB, SmCo 5 , FePt…), strontium ferrite (SrM) has high coercivity H C , large magneto- crystalline
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Phase ﬁeld models have been known as one of the most adequate deterministic models for directlysimulating the dendrite growth morphology, nevertheless, it was not clear how the grain morphologies were inﬂuenced by the constant parameters in the models. In this paper, it was studied quantitativelythat the connection between the growth morphologies and some parameters including undercooling, the coupling coeﬃcient between the temperature ﬁeld and the phase ﬁeld, the anisotropic coeﬃcient and so on. The formation and transformation between the dendrite morphologyand seaweed morphologywere discussed. Besides, the relations between the tip growth speed and the parameters were studied, the theoryof the growth tip branching-oﬀ and the theoryof side-branching were analyzed.
event (400 to 600 mm) over 24 to 48 h (Pias and Stuckmann, 1970; Kallel et al., 1972; Boujarra and Ktita, 2009). The 1979 flood event is characterised by a heavy precipitation during 4 days (Bonvallot, 1979). Only one horizon corresponds to these events in the BL12-10 core. Consequently, we assume that this unique flood deposit registers a period during which these three high-precipitation events occurred (i.e. AD 1969, 1972 and 1979). The activity of 210 Pb in this flood deposit is not disturbed; it is homogeneous (Fig. 10). For this reason we assume that no significant erosion happened in the lagoon during this period. During these heavy precipitation events, most of the sedimentary material was deposited in the flood- plain and the lagoon and probably transported to the Mediter- ranean Sea through the passes. The sedimentation rate corre- sponding to these events is not very high. The thickness of the sediment layer associated with these flood events is low, i.e. about 5 cm. The grain size and geochemical values of this flood deposit are rather homogeneous. This homogene- ity is probably linked to the action of weak bottom currents within the El Bibane Lagoon. Finally, since these three ex- treme flood events are very close together in time (1969– 1979) and the sedimentation rate is low, they are recorded as only one sedimentary deposit (FL2) in our archive. The third flood event FL3 was dated at AD 1945 ± 9 (Fig. 12). It could be associated with the 1932 flood event (Fehri, 2014). This event was characterised by a flash flood event with a pre- cipitation event of 449 mm in a few days. Bonvallot (1979) demonstrated that this event presents a similar characteristic to that of 1979.
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Pollen grain morphological abnormalities were detected under the three different observation techniques (SEM, TEM and LM). The abnormalities were relatively easy to determine in the SEM images, where details of pollen grain surface morphology could be closely examined (Fig. 2). Some debris and bacteria were observed on the SEM images due to unavoidable contamination during harvesting and short-‐term storage (Fig. 2), but the quality of most images was acceptable. An example of different developmental fates for individual pollen grains after mother-‐cell meiosis was seen in a group of three attached pollen grains (probably members of a single tetrad) which contained one normal grain, a misshapen grain and an undeveloped grain (Fig. 3).
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