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Nucleation of Recrystallization of High Purity Aluminium

Nucleation of Recrystallization of High Purity Aluminium

Abstract— Investigating nucleation and recrystallization in high purity aluminium foil during the different heating up rates of annealing, it generally analysed the evolution of microstructure and texture. The improvement of the recrystallization surface in business immaculateness Al containing extensive aluminium cadmium (Alcd) hastens was researched to decide the reliance on the level of disfigurement and recrystallization temperature by methods for X-ray macro texture examination. The recrystallization surfaces create from the challenge between the Cube-introduction, and haphazardly situated grains because of molecule animated nucleation. The development of these introductions is examined regarding their nucleation and ensuing development conduct. Specific consideration is centered around the impact of the procedure parameters, for example strain, temperature and warming rate, on the proportion between the individual introductions in the recrystallization surfaces. The majority of the transformation structural in materials occurs with the help of nucleation and growth this is a heterogeneous transformation that that was first identified by Gibbs, is complete in regions of the structure. With these transformed regions separated with sharp interface from the other untransformed regions. Recrystallization, is such a transformation the recrystallization you can observe that high angle grain boundaries. These homogeneous reactions which occurs in the material and they are delocalised in these initially the transformation was incomplete. You can able to observe two stages that is the first one is nucleation and second one is growth.
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Quenching Studies of Lattice Vacancies in High Purity Aluminium

Quenching Studies of Lattice Vacancies in High Purity Aluminium

(a) The difference between the change of the specimen volume relative to a vacancy-free low-temperature reference state as measured by dilatometry and as calculated from the temperature variation of the lattice parameter gives us the absolute concentration of the vacancies in high-temperature thermal equilibrium. From the point of view of deducing H 1V F , the weakness of this method is its limited sensitivity. It allows only fairly large vacancy concentrations ( ≥ 1 × 10 − 4 ) to be de- termined accurately, of which, however, a substantial fraction may be present as divacancies or even larger agglomerates. Since the method measures the total concentration of vacant lattice sites,
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Microstructural Evolution and Mechanical Properties of High Purity Aluminium Processed by Equal Channel Angular Pressing

Microstructural Evolution and Mechanical Properties of High Purity Aluminium Processed by Equal Channel Angular Pressing

equiaxed grain structure is not simple when the orientation image after 2 passes shown in Fig. 3(b) is inspected. It has a similar orientation throughout the observed area, suggesting that the structure consists of subgrains with grain boundaries having low angle of misorientation. The results of EBSD seem to be consistent with the hardness variation shown in Fig. 1. It is suggested that the dislocation density is high after 2 passes but decreases after 8 passes to form grains with an average grain size of 15 mm. In this study, TEM observation was further conducted to reveal microstructural evolution.
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Production of High Purity Metals: A Review on Zone Refining Process

Production of High Purity Metals: A Review on Zone Refining Process

DOI: 10.4236/jcpt.2018.81003 43 Journal of Crystallization Process and Technology the far end of the bar, even further than any other zone molten scheme. That means through VZS technique, the production value of the final product with the same purity efficiency is considerably higher. But it is not validated experi- mentally due to the huge difficulty in instant adjustment of zone length. With the aim of maximizing the separation of impurities in the first half of the bar in each pass, Ho, et al [47] and Ghosh, et al [48] have conducted more practical op- timization approaches, in which an optimal zone length is quantitatively eva- luated in every single pass. The biggest difference between these two approaches was the dependence (in [47]) or independence (in [48]) of the optimum zone length from distribution coefficients of impurities. In contrast to the above men- tioned works, Spim, et al [28] simulated a model of zone length adaption during different passes. In this model e.g. the zone length is kept equal to 0.2 L for the initial three passes, followed by 0.1 L for the subsequent four to six passes, and then 0.05 L for the remnant passes (L = the total length of the bar). This model is easier to control and its results showed to be even more satisfactory in compari- son with VZS technique.
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High purity Cu nanocrystal synthesis by a dynamic decomposition method

High purity Cu nanocrystal synthesis by a dynamic decomposition method

200°C. As the temperature increases to 250°C, the size of the Cu nanocrystals increases remarkably and some floc- cules can be found among Cu nanocrystals (Figure 5b). Decomposition at 350°C results in a decrease of the floc- cules, implying a higher purity of the Cu nanocrystals. The Cu nanocrystals become larger with the temperature increases to 350°C and 400°C, as shown in Figure 5c, d. These results indicate that lower decomposition tempera- tures favor producing Cu nanocrystals with smaller sizes but lower purity. Higher temperatures are favorable for forming Cu nanocrystals with higher purities, but aggrega- tions of the nanocrystals can easily occur.
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Self Diffusion along Dislocations in Ultra High Purity Iron

Self Diffusion along Dislocations in Ultra High Purity Iron

solution was supplied from New England Nuclear Corpora- tion, U.S.A. A few drops of the solution containing the ra- dioisotope was deposited on the mirror-like surface of the specimen and dried under a heating lamp. Then the speci- men was diffused at temperatures in the range 623–1053 K for 2.7–328.3 ks in a stream of the purified hydrogen gas in furnaces controlled within ± 1 K. To measure the penetra- tion profiles of the radioisotope in the specimen, two types of the serial sputter-microsectioning apparatus were used; the radio-frequency type for long penetration profiles diffused at high temperatures and the ion-beam type for short penetration profiles diffused at low temperatures. The details of the meth- ods were described elsewhere. 9, 10) For each specimen 15–40 successive sections were sputtered. A constant fraction more than 60% of the sputtered-off material was collected on an aluminum foil. The intensity of the radioactivity of the iso- tope in each section was measured by a well-type Tl-activated NaI detector with a 1024-channels pulse height analyzer. 3. Results and Discussion
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Robust control of a high-purity disttilation column using synthesis

Robust control of a high-purity disttilation column using synthesis

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List of high purity metals available from American producers

List of high purity metals available from American producers

All prices given in this report are quoted from the producer and are subject to change. The stated purities and analyses are also those of the producer. We have made no attempt to check these analyses and assume no responsibility as to their reliability. Where more detailed information is needed concerning the latest prices, purity and other shapes of a particular metal, we suggest direct correspondence with the listed producers. It is our intention that only those who produce and supply pure metals be included in this compilation. Some listings include grades of metal of not exceptional purity, especially for some of the less common metals, and are included because they could be of interest in research on alloys where that metal is a minor constituent.
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Simulation of Square Beam Subjected to Side Impact

Simulation of Square Beam Subjected to Side Impact

Figs, 10 and 11 show the impact behaviour for the aluminium structure with two different rib materials, aluminium and steel. The mechanical characteristics are shown in Table 1. It can be seen in Fig. 10 that the aluminium structure with an aluminium rib has the maximum SEA, which is about 15.0827e8 N.mm/ton. On the other hand, Fig. 11 shows that the amount of deflection is approximately the same for the aluminium structure with both aluminium and steel ribs, which is about 3.3 mm. Hence it is again observed that the type of rib material is not a significant factor in the amount of deflection. However, the rigid rib (steel) results in lower SEA and a high impact force.
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Aluminium adjuvants and adverse events in sub-cutaneous allergy immunotherapy

Aluminium adjuvants and adverse events in sub-cutaneous allergy immunotherapy

their efficacy in promoting immune reactions to anti- gens (preventative therapy) and modifying the immune response to allergens (tolerance therapy) respectively. While the detailed mechanisms of their activities as ad- juvants remain to be elucidated [4] their immunopo- tency is testimony to their biological availability and biological reactivity at injection sites and elsewhere in the body. Contrary to the view of a recent otherwise informed commentary [5] aluminium adjuvants are not ‘harmless salts’! They are far from being benign partici- pants in vaccination and immunotherapy and their reac- tivity’s have been associated with adverse events in the recipients of such therapies. Adverse reactions to alu- minium adjuvants might have been avoided if there had been a requirement to demonstrate the safety of their use in humans. However, no such regulations exist and the amount of aluminium salt which is included as an adjuvant is wholly determined by its immuno-efficacy in tandem with the respective antigen or allergen. Indeed it is an anomaly of many trials of the safety of aluminium- adjuvanted vaccines and immunotherapies that the (essen- tially toxic) aluminium adjuvant is considered to be the appropriate placebo in such clinical trials [6].
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INVESTIGATION OF REFINING TECHNIQUE IN ULTRA HIGH PURITY GE FOR PHARMACEUTICAL USE

INVESTIGATION OF REFINING TECHNIQUE IN ULTRA HIGH PURITY GE FOR PHARMACEUTICAL USE

A refiner of vertical zone was built to refine germanium of 8N purity. (Fig. 1A) It is composed of alternate three heating parts and cooling parts. This alignment was made to rapid process the ingot than passing it through a single unit although the effect of final refining remains the same. Ethanol is used as the cooling agent, which is passed through the cooler and a adjustable chiller monitors the cooling agent flow. The cooling part provide to fasten the molten regions produced by the heating part and help to gain qualified crystallization from the melt quickly. Through the heating and cooling part assembly, the tube was made to pass vertically downwards by the lowering and zone travel rate of the tube was fixed at 2.5 cm/h by the drive motor controller. After passing of zone refinement, the zone refined germanium was located into three-dimensional freezing system. This three- dimensional freezing system has individual control for hot, gradient and cold zone phases, shown in Fig. 1B. The hot zone was maintained at 500℃ for 2 hours. The gradient zone temperature was controlled from 200℃ for 2 hours, 75℃ for 2 hours and after which it was fixed at 0℃. Finally, the cold zone temperature was controlled from -20℃ for 0.5 hours, 4℃ for 1 hours and -10℃ for 3 hours. This system consists of a rotation machine for rotating the
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Study on Aluminium Contamination in Mettur Soil and its Subsequent Uptake by Medicinal Plants

Study on Aluminium Contamination in Mettur Soil and its Subsequent Uptake by Medicinal Plants

the correlation between metal levels in plants and the soil in which these plants grow. In the present investigation, we focused on soil aluminium pollution in the Mettur area. It is also called aluminium city of Tamilnadu, having Aluminium plant Called MALCO- Madras Aluminium Company Ltd, Steel industry, Chemplast Sanmar/Mettur Chemicals. Since, it is a place surrounded with aluminium industries, there is a possibility of more aluminium pollution in soil 6 .

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The Production of Ultra-pure Hydrogen124-128

The Production of Ultra-pure Hydrogen124-128

IOO per cent purity. I n practice very high purity can only be achieved by skilful design and by stringent quality control procedures during fabrication to minimise the oc[r]

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Optimal High Purity Acetone Production in a Batch Extractive Distillation Column

Optimal High Purity Acetone Production in a Batch Extractive Distillation Column

In this work, a maximum distillate problem into step 3 of batch extractive distillation operation is considered to be an objective function subject to a given product purity constraints. The reflux ratio is selected as the decision variable to be optimized for the fixed batch time and reboiler heat duty to so as to maximize the weight of the distillate product. The optimization problem can be stated as follows: Maximum Distillate Problem

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The production of low cost solar grade silicon from rice husk

The production of low cost solar grade silicon from rice husk

The shortage o f high purity silicon feedstock stimulated the launching of numerous projects to refine impure silicon to one with acceptable purity. The single crystal has a continuous and unbroken lattice structure that repeat itself. Poly-crystalline or multi-crystalline materials composed o f many small crystals called grains. Metallurgical grade silicon (MG-Si) is multi-crystalline silicon not purified and thus, contains higher concentration o f impurities than all other silicon grades. The grains texture is randomly oriented or has a preferential direction. The regions between the grains are called grain boundaries and are considered to be interfacial defects that are detrimental to electrical and thermal conductivity. In the past 8 - 1 0 years, attempts to make solar cell from metallurgical grade silicon has increased tremendously following the broadly inspired similar attempts during the 70-80s o f last century; using those initiatives to research and develop on commercial low cost solar cell (Bye and Ceccaroli, 2014). Different researcher uses different purification process normally based on several steps with each taking care o f groups of impurities e.g. donor (p), acceptor (B), transition elements etc. Majority o f the processes used are explained in section (2.15). The use o f wafers made from solar grade silicon can reduce cost dramatically. Upgraded metallurgical grade silicon (UMG-Si) is produced via leaching and purifying o f MG-Si, followed by casting process. Multi-crystalline silicon o f about three orders o f magnitude less than S0G-Si or 2 - 4N is resulted. Using
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Effect of Aging on the Tensile Properties of High Purity Fe 50Cr Alloys

Effect of Aging on the Tensile Properties of High Purity Fe 50Cr Alloys

Yoshinaga and Morozumi reported that the friction stress of mobile dislocations caused by dragging solute atmosphere in- creases with decreasing the velocity of dislocation. 5) How- ever, in a Fe-high Cr alloy there is no report about the re- lationship between strain rate relating to dislocation velocity and stress-strain curves visually representing plastic deforma- tion. On the other hand, there are also few reports that de- formation twinning occurs at elevated temperature. Anglada et al. reported that in Fe–28Cr–Mo–Ni alloys deformation twinning appearing at elevated temperatures is related to dy- namic strain aging caused by substitutional atoms, 6) and that
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Influence of Carbon Additions on the Dynamic Recrystallization
of High Purity α Iron

Influence of Carbon Additions on the Dynamic Recrystallization of High Purity α Iron

device, ensuring an homogeneity of 2 Kelvins along the sam- ple height. Argon was used to protect samples and tools from oxidation and prevent them from pollution. Particular atten- tion was paid to the lubrication of the specimens, because the tribological properties of high purity iron are very bad and may lead to sticking phenomena, and very large friction cor- rections. The lubrication procedure was as follows: polishing before each test and deposition of a boron nitride layer (spray) on the sample and the tools. The heating stage was operated with 3 thermal ramps: 105 K/min up to T 1 = ( T testing − 100 K ) ,
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Hydrogen Diffusion Technology12-16

Hydrogen Diffusion Technology12-16

In this high technology industry a reliable supply of high purity gas is regarded as an essential everyday service, and new designs of palladium alloy diffusion un[r]

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High strain rate properties of structural aluminium

High strain rate properties of structural aluminium

As early as 1947, Taylor (38) and Wiffens (39) looked extensively into ballistic compression to investigate material behaviour and dynamic yield strength at high strain rates. Taylor's (38) work was mainly theoretical analysis. Subsequently, he conducted tests to support his analysis by using flat ended transparent cylinders made from cast blocks of paraffin wax. The cylinders were projected by means of a catapult at a rigid anvil. He used the momentum equation, ignoring the radial inertia effect, so that the stress can be considered constant over any cross-section. Wiffens (39) followed in Taylor's (38) steps using the same approach theory. He conducted his tests on steel, copper and lead in the same manner as Taylor's (38), looking as well at the effect of pre-straining on the stress-strain character­ istics . He reported that an increase in the dynamic strength of mild steel can be obtained by pre-straining either in tension or in compression. He also established equations relating stress ratio (dynamic strength/static strength) to the static strength of steel and duralumin.
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The characterisation of AGATA high purity germanium detectors for pulse shape analysis

The characterisation of AGATA high purity germanium detectors for pulse shape analysis

The development of radioactive ion beam (RIB) facilities, including RIBF (Japan), TRIUMF-ISAC (Canada), SPIRAL2 (France), HIE-ISOLDE (Switzerland), FAIR (GSI) and SPES (Italy), allows the study of nuclei far from stability [12]. These facilities provide beams with a broad range of exotic proton- and neutron- rich nuclei. Greater experimental challenges including large background, high Doppler broadening and low count rate require more efficient detector arrays. Highly sensitive -ray spectroscopy tools are necessary to deal with these chal- lenges. The goal of the next stage of development is to create spectrometers strictly from HPGe material with the goal of identification of interactions within a few millimetre throughout the detectors.
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