Papers by Keyword: Growth

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Authors: Manfred Schneider, Günter Gottstein, L. Löchte, Jürgen Hirsch
Authors: Elizabeth A. Holm, Mark A. Miodownik, Kristopher J. Healey
Abstract: The origin of the strain-free crystallites that nucleate the recrystallization process has been debated for decades. Realistic, three-dimensional computer simulations indicate that the nucleation event is the mobility-driven abnormal growth of certain subgrains. Based on these observations, we derive a model that incorporates subgrain topology, texture, boundary distribution and boundary properties to predict the frequency of the abnormal growth events that lead to nucleation. The qualitative and quantitative agreement between theory, simulation, and experiments is excellent.
Authors: Amélie Michel, C. Sabathier, G. Carlot, M. Cabié, S. Bouffard, Philippe Garcia
Abstract: Transmission electron microscopy (TEM) characterizations were carried out on a set of UO2 thin foils previously implanted at room temperature with 400 keV Xe2+ and 250 keV Kr2+ ions at the fluence 7.1015 (equivalent to 1 at.%/at. UO2). The experiment was devoted to the study of the evolution of the fission gases bubbles populations with increasing temperature. Annealings were performed in the laboratory furnace at 600°C, 800°C, 1000°C for 12h, 1400°C for 4h and 1500°C for 2h under Ar-5%H2 atmosphere. For each annealing condition and for as-implanted specimens the bubble population has been characterized in size and number density. A comparison between Xe and Kr has been done that showed a similar behaviour. Globally, from the as-implanted sample to the 1500°C annealed, the bubbles growth phenomenon and the microstructure evolution with temperature was put in relieve.
Authors: Dong Fang Ma, Gao Tao Deng, Da Nian Chen, Shan Xing Wu, Huan Ran Wang
Abstract: The multi-tension loading in the optimized tensile split Hopkinson bar tests for pure copper sheets was used to investigating growth and coalescence of drilled voids in pure copper sheets, recorded by a high-speed camera. The results of scanning electron microscopical investigation of the microvoid evolution in recovered pure copper sheets showed void coalescence mechanisms which are similar to that of visualized drilled voids. The semi-empirical relation [8] for void shape evolution under quasi-static tension was compared with our computed results revealing the dynamic and clustering effects on void growth. The possibility of application of Thomason model[9] and Considere’s condition[10] for void coalescence to thermoviscoplatic constitutive model was explored under impact tension. The main effects affecting dynamic growth and coalescence of voids were presented including the geometry (void size, shape, orientation, spacing), the material properties (dynamic constitutive model) and the stress state (impact tension condition).
Authors: Lei Liu, Qing Cai Su, Mu Sen Li
Abstract: The growth process of synthetic diamond single crystals under high-pressure and high-temperature (HPHT) was investigated using acoustic emission (AE) technique. And AE parameters corresponding to growth process were analyzed. However, the AE features of diamond growth are relativelyweak and easily obscured by other AE sources. So the fast Fourier transformation (FFT) was used to calculate the frequency spectra of AE signals for identifying different AE sources. The results showed that the variation of AE counts and energy is in a good agreement with the formation process of synthetic diamond crystals. And the AE signals pronounced from diamond growth are concentrated in the frequency range from 100 to 250 kHz. Thus, AE technique is an effective way to monitor and study the diamond growth, and the frequency analysis can be a useful way to identify different AE sources.
Authors: Harshad K.D.H. Bhadeshia
Authors: Yu Hong Wu, Xu Cheng, Qing Nian Cai, Chao Wen Lin
Abstract: In laboratory bioassay, conducted to study the allelopathic influence of aqueous extracts (0, 2.5, 5.0, 7.5, 10.0% concentration) of twelve hedgerow plant species (Amorpha fruticosa L., Citrus reticulate Banco., Coronilla varia L., Eriobotrya japonica Thunb., Eulaliopsis binata Retz., Gynura bicolor DC., Hemerocallis citrine Baroni., Medicago sativa L., Morus alba L., Toona sinensis Roem., Vetiveria zizanioides L., Zanthoxylum schinifolium Sieb.) which planted in the purple hilly area of Sichuan basin in China was on the germination and seedling growth of wheat (Triticum astivum L.). At 10.0% concentration, The aqueous extracts of twelve hedgerow plant species significantly inhibited the seed germination and seedling growth of wheat except that A. fruticosa, E. binata and V. zizanioides extracts had no effect or slight inhibition on germination of wheat, but the degree of inhibition was species dependent. The allelopathic effect of aqueous extracts from hedgerow plants on wheat was maximum with G. bicolor, H. citrine, C. varia and M. sativa in terms of germination, and G. bicolor , M. sativa, M. alba and H. citrine in terms of shoot length, root length and dry weight, respecitively. The degree of inhibition increased with increase in concentration. Duplication of this work under field conditions is needed, for which the results of this study will form a valuable base.
Authors: Ling Xiao, Yan Hua Sun, Chun Hua Ding, Chao Zhu, Lie Yu
Abstract: Two-phase thin solid films consisted of Au nanoparticles imbedded in an amorphous matrix were prepared via a series of galvanic replacement reactions between chloroauric acid solution and reducing metals. The Au nanoparticles were in situ crystallized from the amorphous films rather than precipitated from solution directly. Amorphous films with partly crystallized Au nanoparticles only existed stably in dilute chloroauric acid solution. The higher concentration of chloroauric acid evidently promoted the strain-induced crystallization process and accelerated the crystallization of amorphous films into Au nanoparticles with many stacking faults, twins and dislocations. The coexistence of amorphous and crystalline Au nanoparticles makes it possible to synthesize two-phase nanostructured films.
Authors: Davinder Singh, Jaimal Singh Khamba, Tarun Nanda
Abstract: Micro, Small and Medium Enterprises (MSMEs) have been noted to play a significant role in promoting economic growth in less developed countries, developing and also in developed countries. Worldwide, the micro and small enterprises have been accepted as the engine of economic growth of any nation. Small and Medium Enterprises are the backbone of the economies, because it trigger employment, output, export, poverty alleviation, economic empowerment, economic development etc. in developed as well as in developing countries. It is more important to developing countries as the poverty and unemployment are burning problems. MSMEs have been playing a momentous role in overall economic development of a country like India where millions of people are unemployed or underemployed. Therefore, the growth of small sectors is essential for the growth in the GDP, employment generation, total manufacturing production and export. India, being one of the fastest growing economies of the world, needs to pay an honest attention for the utmost growth of MSMEs for its increased contribution in above areas.
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