Hot Grains Research Articles

Pertumbuhan Dan Hasil Padi (Oryza sativa. L) Melalui Aplikasi Zink Sulfat

East Java rice production in 2021 reach 9.79 million tons.ha-1, but it decrease to 9.69 million tons.ha-1 in 2022. One effort to increase rice production can be done by adding zinc sulfate. Zinc plays a role in increasing the photosynthetic metabolism of plants, thereby it’s triggering growth and yield of rice. This study aims to examine the effect of the addition and time of application of zinc sulfate on rice growth and yield. The experiment was designed using a factorial Completely Randomized Design (CRD) consisting of 2 factors and 4 replications. The first factor was the dose of zinc sulfate which consisted of 4 levels: 0, 8, 12, and 16 kg.ha-1. The second factor was the application time, namely 10 dap and 40 dap. The results showed that there was no interaction between zinc sulfate dosage and application time on rice growth and yield. The application of zinc sulfate 16 kg.ha-1 showed significant results on plant height (144.83 cm), number of tillers (28.33 tillers), number of hot grain per panicle (122.58 grains) and weight of grain per clump (47.13 g ). The addition of a zinc sulfate dose of 16 kg.ha-1 was able to increase plant photosynthetic activity and assist in the process of preparing protein so that it affected rice growth and production. While the application of zinc sulfate at the age of 40 dap showed a significant effect on the number of grain per panicle (121.95 grains). This is because the addition of zinc sulfate in the flowering phase can reduce the risk of increased formation of abscisic acid which can cause loss of flower buds and abnormal growth of anthers and pollen grains.

Granular material drying and energy analysis of a scaled-up rotating fluidized bed dryer of fixed geometry

The present investigation is focused on the grain drying in a scaled-up rotating fluidized bed in static geometry (RFB-SG) dryer, and then gradual cooling of the dried hot grains in the temperature stabilization unit (TSU). A freshly harvested crop in abundance seeks massive energy consumption in the drying process. Hence, to minimize these losses, energy-exergy analysis of grain-drying, for the inventory of 500 to 3000 g paddy, at temperature of 328–338 K and AFR 400–600 m3/h. It is observed that with the increase of drying air velocity and drying temperature positively affect both the production rate and production cost. Due reduction in drying time, cost, and energy requirement, the drying efficiency is improved. The energy utilization is found to be maximum of 3.52 kJ/s, at the AFR of 600 m3/h and the temperature of 338 K. Furthermore, the time of temperature stabilization of dried grains is observed 38 s with no effect on the nutritional value of the grains.

ИСПОЛЬЗОВАНИЕ СУШИЛКИ С-40 ПРИ ДВУХСТАДИЙНОЙ СУШКЕ ЗЕРНА КУКУРУЗЫ

The paper provides rationale for safe modes and methods for calculating a two-stage drying technology with partial recirculation of grain, in which the grain is under-dried by 2…3% to the standard humidity in a grain dryer, and the hot grain is cooled by active ventilation with outside air, while drying it to the standard humidity. The safe mode of two-stage drying in S-40 provides for partial recirculation of grain with moisture removal close to the standard, and the moisture content of the recirculated mixture not exceeding 18%. The recirculation coeffi cient calculated based on this condition is used to determine the temperature of the recirculating grain mixture, taking into account the reversible component in the shaft dryer. The minimized recirculation ratio provides for the permissible unevenness in drying and minimal fracturing. The recirculation drying process was analyzed according to the standard method, but with the adjusted values of moisture removal and temperature of the grain mixture. Economic tests of the S-40 dryer were carried out using a two-stage technology on corn grain. It has been experimentally established that the S-40 dryer with a recirculation coeffi cient of 2 and a moisture pick-up of 4% per cycle when drying corn grain with a moisture content of 23.5 to 15.6%, at a drying agent temperature of 95°C, provides a throughput of 10 t/h (without refrigeration). Cooling was carried out in the warehouse. No signifi cant changes in the quality of dried and cooled grain have been established: the starch content and fracturing practically did not change; the unevenness of the dried seeds did not exceed the original requirements. The expediency of using the S-40 direct-fl ow dryer in the recirculation mode has been experimentally established.

Spatially resolving the chemical composition of the planet building blocks

ABSTRACT The inner regions of protoplanetary discs (from ∼0.1 to 10 au) are the expected birthplace of planets, especially telluric. In those high-temperature regions, solids can experience cyclical annealing, vapourisation, and recondensation. Hot and warm dusty grains emit mostly in the infrared domain, notably in N-band (8–13 μm). Studying their fine chemistry through mid-infrared spectro-interferometry with the new Very Large Telescope Interferometer (VLTI) instrument Multi AperTure mid-Infrared SpectroScopic Experiment (MATISSE), which can spatially resolve these regions, requires detailed dust chemistry models. Using radiative transfer, we derived infrared spectra of a fiducial static protoplanetary disc model with different inner-disc (<1 au) dust compositions. The latter were derived from condensation sequences computed at local thermodynamic equilibrium (LTE) for three initial C/O ratios: subsolar (C/O = 0.4), solar (C/O = 0.54), and supersolar (C/O = 1). The three scenarios return very different N-band spectra, especially when considering the presence of sub-micron-sized dust grains. MATISSE should be able to detect these differences and trace the associated sub-au-scale radial changes. We propose a first interpretation of N-band ‘inner-disc’ spectra obtained with the former VLTI instrument MID-infrared Interferometric instrument (MIDI) on three Herbig stars (HD 142527, HD 144432, HD 163296) and one T Tauri star (AS 209). Notably, we could associate a supersolar (‘carbon-rich’) composition for HD 142527 and a subsolar (‘oxygen-rich’) one for HD 1444432. We show that the inner-disc mineralogy can be very specific and not related to the dust composition derived from spatially unresolved mid-infrared spectroscopy. We highlight the need for including more complex chemistry when interpreting solid-state spectroscopic observations of the inner regions of discs, and for considering dynamical aspects for future studies.

STUDY OF MOISTURE ABSORPTION OF SWEET CORN GRAIN OF DIFFERENT FRACTIONS

In Ukraine, as the raw material for the production of cereals, flour, flakes, the following main crops are used: wheat,barley, buckwheat, oats, corn, rice, millet, peas. The volume of world grain production has grown significantly in recentyears. In Ukraine, corn is the main fodder crop, and only a small amount is used as a food. Corn has the leading place amongthe major grain crops in world agricultural production. Corn grain production is concentrated in warm regions. In some regions,corn is the basis of the traditional nutrition of the population, but basically it forms part of the feed in the feeding offarm animals.Today about 3500 food and technological products are produced from corn. Corn can largely satisfy the needs oflivestock, its share is almost 30% of concentrated feed. With the advent of new directions in the development of biotechnologyin the world, the significance of this culture will increase even more. The programs of biofuel production are gaining momentum,in connection with which a significant expansion of the sown area under the corn is foreseen.In this article features of water-heat treatment of corn grain during preparation for processing are provided. Featuresof the use of hot and cold grain conditioning in the cereal industry are considered. In the course of this study, it wasdetermined that the optimum water temperature for humidifying corn sugar is 60 ºС. Using a certain water temperature duringhumidification will enable to perform more efficiently the directed change of technological properties of grain, to ensurethe high efficiency of its further processing. The results of research of the water absorption capacity of sugar corn grain arepresented. As can be seen from the research carried out to improve the efficiency of the STI and optimize the processing technology,the grain lots are fractionated into more homogeneous flows of physical properties and treated separately.

Hot grain dynamics by electric charging and magnetic trapping in debris disks

The recent discovery of hot dust grains in the vicinity of main-sequence stars has become a hot issue among the scientific community of debris disks. Hot grains must have been enormously accumulated near their sublimation zones, but it is a mystery how such a high concentration of hot grains is sustained. The most difficult conundrum is that the size of hot dust grains is estimated to lie in the submicrometer range, while submicrometer-sized grains are instantly swept away from near-stellar environments by stellar radiation pressure. One and only mechanism proposed for prolonging the residence time of hot grains in the near-stellar environments is trapping of charged nanoparticles by stellar magnetic fields. We revisit the model of magnetic grain trapping around main-sequence stars of various spectral classes by taking into account sublimation and electric charging of the grains. The model of magnetic grain trapping predicts that hot dust grains are present in the vicinity of main-sequence stars with high rotation velocities and intermediate magnetic-field strengths. On the contrary, we find that the detection of hot dust grains has no correlation with the rotation velocities of central stars nor the magnetic field strengths of the stars. Our numerical evaluation of electric grain charging indicates that the surface potential of submicrometer-sized grains in the vicinity of main-sequence stars is typically 4– 5V, which is one order of magnitude smaller than the value assumed by the model of magnetic grain trapping. On the basis of our numerical simulation on sublimation of dust grains in the vicinity of a star, it turns out that their lives end due to sublimation in a timescale much shorter than the period of one revolution at the gyroradius. It is, therefore, infeasible to dynamically extend the dwell time of hot grains inside the sublimation zone by magnetic trapping, while we cannot completely rule out the possibility of magnetic grain trapping outside the sublimation zone where the strength of stellar magnetic field has been underestimated in the previous model. Nevertheless, the independence of hot dust detection on the stellar rotational velocity and magnetic field strength favors a scenario that some other (yet unnoticed/overlooked) ubiquitous mechanism of grain trapping is at work.

Effect of sulphur and acid soluble aluminium content on grain oriented silicon steel

The effect of sulphur (S) and acid soluble aluminium (Als) content on precipitation behaviours, microstructures and textures of hot rolled grain oriented silicon steels were investigated. The results showed that precipitates were mainly MnS and a little amount of MnS–AlN composite. Similar characteristics of precipitates, microstructures and textures were found in specimens containing similarly higher S content and different Als content. More fine precipitates, less recrystallisation and more and stronger Goss texture component were presented in specimen containing lower S content. It was not Als content but S content that played a key role during hot rolling. High proportion and intensity of Goss texture component were due to the effective inhibiting effect of finely and uniformly dispersed precipitates on dynamic recrystallisation.

Effect of Nitrogen Content on Hot Deformation Behavior and Grain Growth in Nuclear Grade 316LN Stainless Steel

316LN stainless steel with 0.08%N (08N) and 0.17%N (17N) was compressed at 1073–1473 K and 0.001–10 s−1. The hot deformation behavior was investigated using stress-strain curve analysis, processing maps, and so forth. The microstructure was analyzed through electron backscatter diffraction analysis. Under most conditions, the deformation resistance of 17N was higher than that of 08N. This difference became more pronounced at lower temperatures. The strain rate sensitivity increased with increasing temperature for types of steel. In addition, the higher the N content, the higher the strain rate sensitivity. Hot deformation activation energy increased from 487 kJ/mol to 549 kJ/mol as N concentration was increased from 0.08% to 0.17%. The critical strain for initiation of dynamic recrystallization was lowered with increasing N content. In the processing maps, both power dissipation ratio and unstable region increased with increasing N concentration. In terms of microstructure evolution, N promoted dynamic recrystallization kinetic and decreased dynamic recrystallization grain size. The grain growth rate was lower in 17N than in 08N during heat treatment. Finally, it was found that N favored twin boundary formation.

Multiscale Modeling for 42CrMo Ring during Blank-casting and Rolling Compound Forming Process

A modeling approach coupling with both macroscopic and microscopic as-cast 42 CrMo alloy ring short process flow casting-rolling compound forming process is proposed based on finite element(FE) theory and cellular automata(CA) model. Within the theory framework of casting-rolling compound forming new process, boundary transition conditions of macro/micro interfaces are defined in consideration of ring hot deformation behavior and grain special topological structure, these boundary conditions are contribute to solve the bottleneck problem of controlling ring shape/property. Within the framework of CA model, the grain topology deformation technology is studied, the space overlapping problem of grain structures are considered fully and the grain topological structures are optimized by using the independent component analysis. The hybrid model is applied to simulate the ring short process flow casting-rolling compound forming process. The results indicate that hybrid modeling can simulate process respectively by using different level macro micro models according to different scales of the integral and the local of a ring, the simulation efficiency of ring short process flow casting-rolling compound forming process is enhanced effectively.

Die and Process Design for Hot Forging of a Gear Wheel – A Case Study

Gearing components are an example for widely used machining parts in engines. Nowadays the development and optimization of materials and process chains are driven towards a concurrent improvement of final product properties and production efficiency. Excellent mechanical properties needed for gearing components e.g. high load capacity and high fatigue resistance depend on a fine homogeneous microstructure in the final product. Efficiency in gear manufacturing can be optimized by increasing the temperature during processing, which allows for lower forging loads and lower die stresses, thus improving die life in terms of mechanical fatigue. Additionally, increasing the temperature during case hardening reduces the process duration significantly. Hence process efficiency also increases. To meet the need of a fine homogenous microstructure, dynamic recrystallization has to be initiated during hot forging and grain growth has to be avoided during dwell times and case hardening. This grain size control can be achieved by applying micro-alloying concepts. Recently, an Nb-Ti-based alloying concept for case hardening steels was introduced, which increases fine grain stability and therefore potentially allows for higher forging and case hardening temperatures, leading to improved process efficiency [1]. In this paper a 25MoCr4-Nb-Ti steel grade is characterized in terms of flow resistance and microstructure evolution by hot compression tests and annealing experiments. The processing limits of this material in terms of abnormal grain growth are determined and a JMAK-based microstructure model considering these limits is presented and implemented in the FE-Software DEFORM 3dTM. The model is used in a case study to design a laboratory scale forging process for lowest possible die stresses and finest possible grain sizes. Experimentally measured grain sizes and forging loads from forgings at the laboratory scale are used to evaluate the process design. It is shown that considering microstructure evolution in process design is absolutely necessary to jointly optimize for process efficiency and final properties. The application of the Nb-Ti-based micro-alloying concepts allows for lower die stresses and thus seems to reduce mechanical fatigue of the dies compared to conventional case-hardening steels. [1] S. Konovalov et. al.: Testcase gearing component. In: G. J. Schmitz, U. Prahl (Ed.): Integrative Computational Materials Engineering, Wiley-VCH Verlag GmbH & Co. KGaA, 2012, ISBN 978-3-527-33081-2

INFRARED SPECTRAL MAPPING OF SUPERNOVA REMNANTS. I. N63A AND ITS ENVIRONMENT

We present Spitzer Space Telescope spectra of the supernova remnant (SNR) N63A and its native H II region N63 in the Large Magellanic Cloud. We measure nebular fine-structure lines, H2 lines, and polycyclic aromatic hydrocarbons (PAHs). The lines contribute half of the flux in the Spitzer 24 μm image of N63A shocked lobes, but only ≤10% elsewhere. The mid-IR flux is largely due to thermal continuum emission from dust in and around N63A plasma. Electron densities are low everywhere; the differences in mid-IR line ratios separate N63A plasma and its high-excitation surroundings from N63A low-excitation optical lobes. We compare the observed line fluxes and ratios within N63A's shocked lobes and plasma with the predictions from models for moderate and fast shocks to constrain pre-shock densities and shock velocities. N63A's photoionized lobe contains a warm photodissociation region in pressure equilibrium with optically ionized gas. We apply a physical dust model to our spectra supplemented by MIPS photometry. We derive the intensity of radiation heating the dust, the mass fraction due to PAHs, and the masses of dust within our sampled regions and of cooler grains in the diffuse interstellar medium. N63A's shocked lobes and plasma contain ~0.07 M ☉ of hot grains, comparable to amounts in other SNRs. Within N63A there is ~0.7 M ☉ of warm grains exposed to ≥100 times the intensity of the local interstellar radiation field. Within the regions, 92% of the total dust mass resides in cool grains emitting ≤27% of their mid-IR luminosity.

EVOLUTION OF COATED GRAINS IN SPIRAL SHOCKS OF SELF-GRAVITATING PROTOPLANETARY DISKS

We investigate the evolution of grains composed of an ice shell surrounding an olivine core as they pass through a spiral shock in a protoplanetary disk. We use published three-dimensional radiation-hydrodynamics simulations of massive self-gravitating protoplanetary disks to extract the thermodynamics of spiral shocks in the region between 10 and 20 AU from the central star. As the density wave passes, it heats the grains, causing them to lose their ice shell and resulting in a lowering of the grain opacity. In addition, since grains of different sizes will have slightly different temperatures, there will be a migration of ice from the hotter grains to the cooler ones. The rate of migration depends on the temperature of the background gas, so a grain distribution that is effectively stable for low temperatures, can undergo an irreversible change in opacity if the gas is temporarily heated to above $\sim 150$\,K. We find that the opacity can drop more, and at a significantly faster rate throughout the spiral shocks relative to the prediction of standard dust grains models adopted in hydrodynamical calculations of protoplanetary disks. This would lead to faster gas cooling within spiral arms. We discuss the implications of our results on the susceptibility of disk fragmentation into sub-stellar objects at distances of a few tens of astronomical units.

Radiation thermo-chemical models of protoplanetary discs - III. Impact of inner rims on spectral energy distributions

We study the hydrostatic density structure of the inner disc rim around HerbigAe stars using the thermo-chemical hydrostatic code ProDiMo. We compare the Spectral Energy Distributions (SEDs) and images from our hydrostatic disc models to that from prescribed density structure discs. The 2D continuum radiative transfer in ProDiMo includes isotropic scattering. The dust temperature is set by the condition of radiative equilibrium. In the thermal-decoupled case the gas temperature is governed by the balance between various heating and cooling processes. The gas and dust interact thermally via photoelectrons, radiatively, and via gas accommodation on grain surfaces. As a result, the gas is much hotter than in the thermo-coupled case, where the gas and dust temperatures are equal, reaching a few thousands K in the upper disc layers and making the inner rim higher. A physically motivated density drop at the inner radius ("soft-edge") results in rounded inner rims, which appear ring-like in near-infrared images. The combination of lower gravity pull and hot gas beyond ~1 AU results in a disc atmosphere that reaches a height over radius ratio z/r of 0.1 while this ratio is 0.2 only in the thermo-coupled case. This puffed-up disc atmosphere intercepts larger amount of stellar radiation, which translates into enhanced continuum emission in the 3- 30 micron wavelength region from hotter grains at ~500 K. We also consider the effect of disc mass and grain size distribution on the SEDs self-consistently feeding those quantities back into the gas temperature, chemistry, and hydrostatic equilibrium computation.

A simple model to interpret the ultraviolet, optical and infrared emission from galaxies

We present a simple, largely empirical but physically motivated model to interpret the mid- and far-infrared spectral energy distributions of galaxies consistently with the emission at ultraviolet, optical and near-infrared wavelengths. Our model relies on an existing angle-averaged prescription to compute the absorption of starlight by dust in stellar birth clouds and in the ambient ISM in galaxies. We compute the spectral energy distribution of the power reradiated by dust in stellar birth clouds as the sum of three components: a component of PAHs; a mid-IR continuum characterising the emission from hot grains; and a component of warm grains in thermal equilibrium with adjustable temperature. In the ambient ISM, we fix for simplicity the relative proportions of these three components to reproduce the spectral shape of diffuse cirrus emission in the Milky Way, and we include a component of cold grains in thermal equilibrium with adjustable temperature. Our model can be used to derive statistical constraints on the star formation histories and dust contents of large samples of galaxies using UV, optical and IR observations. We illustrate this by deriving median-likelihood estimates of the star formation rates, stellar masses, effective dust optical depths, dust masses, and relative strengths of different dust components of 66 well-studied nearby star- forming galaxies from the Spitzer Infrared Nearby Galaxy Survey (SINGS). From this analysis, we conclude that the mid- and far-IR colours of galaxies correlate strongly with the specific star formation rate, as well as with other galaxy-wide quantities connected to this parameter. Our model can be straightforwardly applied to interpret UV, optical and IR spectral energy distributions from any galaxy sample. [abridged]

Radiative transfer revisited for emission lines in photon dominated regions

Context. Transfer in lines controls the gas cooling of photon dominated regions (PDR) and provides many of the observational constraints that are available for their modelling. Aims. The interpretation of infrared and radio observations by the new generation of instruments, such as Herschel, requires sophisticated line radiative-transfer methods. The effect of dust emission on the excitation of molecular species in molecular regions is investigated in detail to explicitly show the origin of various approximations used in the literature. Application to H2O is emphasised. Methods. The standard 1D radiative transfer equation is written as a function of the space variable (as opposed to the usual optical depth). This permits to simultaneously consider all pumping contributions to a multi-level species in a non-uniform slab of dust and gas. This treatment is included in the Meudon PDR Code (available at http://aristote.obspm.fr/MIS/). Results. Infrared emission from hot grains at the edge of the PDR may penetrate deep inside the cloud, providing an efficient radiation source to excite some species at a location where cold grains no longer emit. This leads to non-negligible differences with classical escape probability methods for some lines, e.g. water. Cooling efficiency does not follow directly from line emissivities. The infrared pumping contribution leads to a higher excitation that enhances collisional de-excitation and reduces cooling efficiency.

A near-infrared interferometric survey of debris disk stars

Context.The quest for hot dust in the central region of debris disks requires high resolution and high dynamic range imaging. Near-infrared interferometry is a powerful means to directly detect faint emission from hot grains.

Response of storage molds to different initial moisture contents of maize (corn) stored at 25 °C, and effect on respiration rate and nutrient composition

Maize was stored for 2 months in chambers maintained at 25 °C to simulate conditions observed in the central part of the “Corn Belt” of the United States when the grain warms because of high summertime temperatures after a period of winter storage. Maize was brought to three moisture contents (m.c.) within the range typically observed in farm and commercial storage, and was inoculated to simulate the amount of storage mold contamination typical of this situation. Certain of the experimental units were packed in insulation so that heat could accumulate within the grain masses to simulate hot spots. The wettest grain heated rapidly and became semi-anaerobic. The hot grain then dried rapidly, with the amount of moisture loss influenced by the ratio of water vapor pressures inside and outside the grain. The hot grain cooled and became more aerobic over time. New infections by storage molds, disappearance of viable field molds, development of kernel damage, and changes in atmospheric gases within the grain masses were correlated with the grain moisture or temperature and the rate at which the moisture and temperature changed. The rate of increase in new kernel damage was as high as 3.3% per week. Both the rate of respiration and the estimated ratio of starch to fat consumed were associated with the mean grain m.c. during the trial, and the estimated ratio of starch to fat consumed was in the range of 2.2/1–2.6/1 in the grain containing 16.6–18.2% m.c. That both fat and starch were consumed calls into question loss estimates based on starch metabolism alone. The fat content of the grain decreased more than 10% in some experimental units, but increased less than 5% in others. The protein content generally increased as other grain constituents were consumed.

Further 2MASS mapping of hot dust in planetary nebulae

We have used 2 Micron All Sky Survey (2MASS) mapping results to investigate the distribution of hot dust continua in 12 planetary nebulae (PNe). The nature of this emission is unclear, but it is possible that where the continuum is extended, as is the case for M 1-12 and NGC 40, then the grains concerned may be very small indeed. The absorption of individual photons by such grains may lead to sharp spikes in temperature, as has previously discussed for several other such outflows. Other sources (such as MaC 1-4, He 2-25, B1 2-1 and K 3-15) appear to be relatively compact, and the high temperatures observed are understandable in terms of more normal heating processes. It is possible that the grains in these cases are experiencing high radiant flux levels. Finally, it is noted that whilst the core of M 2-2 appears to show hot grain emission, this is less the case for its more extended envelope. The situation may, in this case, be similar to that of NGC 2346, in which much of the emission is located within an unresolved nucleus. Similarly, it is noted that in addition to hot dust and gas thermal continua, the emission in the interior of NGC 40 may be enhanced through rotational–vibrational transitions of H2, and/or the 2p3P0–2s3S transition of He i.

Hot dust haloes in planetary nebulae

We point out that many planetary nebulae (PNe) have large infrared indices (H-Ks), and that this is likely to result from the presence of hot grains, and/or H 2 S(1) line emission at λ = 2.122 μm. We are able to identify two groups of sources associated with each of these mechanisms, both of which appear to possess distinct physical characteristics. One difference between these groups concerns the near-infrared dimensions of the sources. It appears that hot dust outflows frequently have sizes θ(K S ) > θ(H) > 0(J). Four of the sources are particularly extreme in this regard, and show emission extending well outside of the primary shells. We propose that this is likely to arise from high-temperature grains located in low-density haloes. The location of such grains at large distances from the central stars represents a challenge for any mechanism purporting to explain this phenomenon. The most likely explanation appears to be in terms of photon heating of very small grains.

An Impingement – Spheroidisation Theory for Nucleation and Grain Growth

In an investigation of nucleation of recrystallisation in an Interstitial Free steel it was found that new crystals were almost always contained within the rolled-out hot band grain envelopes and were mostly equiaxed. At a later stage they grew and had an aspect ratio of 2:1 but at the completion of recrystallisation were again equiaxed. This is explained by the notion that nucleation occurs relatively frequently in certain grains, that these nuclei have very similar orientations and are thus orientation pinned within the solute and precipitate containing envelopes of the hot band grains. Provided the misorientation is small the impinged group are capable of spheroidisation provided the driving force across the pinned boundary is sufficient to overcome the pinning, because, by definition, this pinned boundary is of high angle character. The theory, as it is presented as coalescence, relies on a form of Östwald ripening and therefore provides a possible explanation of why grain growth kinetics obeys a time exponent of between 1/2 and 1/3. A similar observation of high aspect ratio grains has been made many times in the case of cold rolled copper which forms cube texture. Again, nuclei are formed in the cube bands, but these are prevented from lengthening because of orientation pinning. However, when the length of a group of such impinged nuclei is sufficient, spheroidisation will produce equiaxed grains.