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Halim Cevizci

References Boshoff D., Webber-Youngman R. C. W., 2011. Testing stemming performance, possible or not? The J. ofthe South African Inst. of Min. and Metall., December, p. 871-874. Cevizci H., 2012. A newly developed plaster stemming method for blasting. The J. of the South African Inst. of Min. and Metall., December, p. 1071-1078. Cevizci H., Özkahraman H. T., 2012. The effect of blast hole stemming length to rockpile fragmentation at limestone quarries. International Journal of Rock Mechanics and Mining Sciences, vol. 53, p. 32-35. Devine J., Beck

Open access

A. Kruk, G. Cempura, S. Lech and A. Czyrska -Filemonowicz

Abstract

Allvac 718Plus (718Plus) is a high strength, corrosion resistant nickel- based superalloy used for application in power generation, aeronautics and aerospace industry. The 718Plus microstructure consists of a γ matrix with γ’-Ni3(Al,Ti) and some δ- Ni3Nb phases as well as lamellar particles (η-Ni3Ti, η*-Ni6AlNb or Ni6(Al,Ti)Nb) precipitated at the grain boundaries.

The primary strengthening mechanism for this alloy is a precipitation hardening, therefore size and distribution of precipitates are critical for the performance of the alloy. The aim of this study was to characterize precipitates in the 718Plus superalloy using Scanning Transmission Electron Microscope combined with Energy Dispersive X-ray Spectroscopy (STEM-EDX) and Focused Ion Beam Scanning Electron Microscope (FIB-SEM). The STEM-EDX and FIB-SEM tomography techniques were used for 3D imaging and metrology of the precipitates. Transmission electron microscopy and EDX spectroscopy were used to reveal details of the 718Plus microstructure and allow determine chemical composition of the phases. The study showed that electron tomography techniques permit to obtain complementary information about microstructural features (precipitates size, shape and their 3D distribution) in the reconstructed volume with comparison to conventional particle analysis methods, e.g. quantitative TEM and SEM metallography

Open access

M. Pawlyta, K. Labisz and K. Matus

Abstract

Aluminium recycling is cost-effective and beneficial for the environment. It is expected that this trend will continue in the future, and even will steadily increase. The consequence of the use of recycled materials is variable and difficult to predict chemical composition. This causes a significant reduction in the production process, since the properties of produced alloy are determined by the microstructure and the presence of precipitates of other phases. For this reason, the type and order of formation of precipitates were systematically investigated in recent decades. These studies involved, however, only the main systems (Al-Cu, Al-Mg-Si, Al-Cu-Mg, Al-Mg-Si-Cu), while more complex systems were not analysed. Even trace amounts of additional elements can significantly affect the alloy microstructure and composition of precipitates formed. This fact is particularly important in the case of new technologies such as laser surface treatment. As a result of extremely high temperature and temperature changes after the laser remelting large amount of precipitates are observed. Precipitates are nanometric in size and have different morphology and chemical composition. A full understanding of the processes that occur during the laser remelting requires their precise but also time effectively phase identification, which due to the diversity and nanometric size, is a major research challenge. This work presents the methodology of identification of nanometer phase precipitates in the alloy AlSi9Cu, based on the simultaneous TEM imaging and chemical composition analysis using the dispersion spectroscopy using the characteristic X-ray. Verification is performed by comparing the simulation unit cell of the identified phase with the experimental high-resolution image.

Open access

Ramya Prasanthi Mokkapati, Jayasravanthi Mokkapati and Venkata Nadh Ratnakaram

, G.M., Chen, L., Deng, J.H., Zhang, X.R. & Niu, Q.Y. (2012). Copper (II) removal by pectin–iron oxide magnetic nanocomposite adsorbent. Chem. Eng. J. 185, 100–107. DOI: 10.1016/j.cej.2012.01.050. 21. Li, K., Fu, S., Zhan, H., Zhan, Y. & Lucia, L. (2010). Analysis of the chemical composition and morphological structure of banana pseudo-stem. Bioresources 5(2), 576–585. DOI: 10.15376/biores.5.2.576-585 22. Firdous, R. & Gilani, A.H. (2001). Changes in chemical composition of sorghum as influenced by growth stages and cultivar. Asian Australas. J

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Łucja Dybowska-Sarapuk, Sławomir Rumiński, Grzegorz Wróblewski, Marcin Słoma, Anna Młożniak, Ilona Kalaszczyńska, Małgorzata Lewandowska-Szumieł and Małgorzata Jakubowska

Res. 4(7), 675–684. DOI: 10.1007/s12274-011-0123-z. 3. Jangho, K., Kyoung, S.C., Yeonju, K., Ki-Tack, L., Hoon, S., Yensil, P., Deok-Ho, K., Pill-Hoon, C., Chong-Su, C., Soo, Y.K., Yun-Hoon, C. & Jong, H.C. (2013). Bioactive effects of graphene oxide cell culture substratum on structure and function of human adipose-derived stem cells. J. Biomed. Mater. Res. Part A. 101(12), 3520–3530. DOI: 10.1002/jbm.a.34659. 4. Carrow, J.K. & Gaharwar, A.K. (2015). Bioinspired Polymeric Nanocomposites for Regenerative Medicine. Macromol. Chem. Phys. 216(3), 248

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Fred Coolborn Akharaiyi and Obehi Betsy Ugberase

-284. 22. Lee K.W., Kim Y.J., Kim D.O., Lee H.J., Lee C.Y. (2003), Major phenolics in apple and their contribution to the total antioxidant capacity, J. Agric and Food Chem ., 51(22), pp. 6516–6520. http://dx.doi.org/10.1021/jf034475w 23. Maitera O.N., Khan M.E., James T. F. (2011), Phytochemical analysis and the chemotherapeutics of leaves and stem-bark of Nauclealatifolia grown in Hong, Adamawa State Nigeria, Asian J. Plant Sci. and Res ., 1(3)., pp.16-22. 24. Matthews K. R. (2006) Microorganisms associated with fruits and vegetables, In Microbiology

Open access

Y. Matsuoka, K. Watanabe, J. Nakamura, W. Lefebvre, S. Saikawa, S. Ikeno and K. Matsuda

Abstract

In this study, the early stage of aging in Mg-Gd-Y alloys has been observed by transmission electron microscopy (TEM), high angle annular dark field – scanning transmission electron microscopy (HAADF-STEM) and calculations of images and electron density and bond overlap population (BOP) by first principal to understand the origin of precipitation in this alloy. The small hexagon of 0.37 nm is the first precipitate in this alloy, and this is the evidence of short range ordering of D019 structure. This is referred as the pre β”-phase. In the peak aged condition, β’ phase with bco structure was mainly observed.

Open access

M. Rozmus-Górnikowska and M. Blicharski

The aim of this work was to investigate the microsegregation and precipitates formed due to segregation in Inconel 625 arc weld overlay coatings on boiler pipes. Examination of microsegregation and precipitates were carried out by means of a scanning electron microscope (SEM) equipped with an EDS detector as well as a transmission electron microscope (TEM) equipped with a HAADF (STEM) and an EDS detectors. The presence of precipitations in the weld overlay was also confirmed with X-ray diffraction analysis (XRD) of residue in the form of powder that remained after the electrolytic dissolution of weld overlay matrix.

The investigations showed that the interdendritic regions were considerably enriched during microsegregation with Nb, and less so with Mo. The distribution of Cr and Fe in the weld overlay is relatively uniform. The value of the partition coefficient k for Mo and Nb is lower than 1. Therefore, these elements segregate during solidification into the liquid and, once solidification is finished, the interdendritic regions are considerably enriched with these elements. The value of k for Cr, Ni and Fe are only slightly higher than 1. Though the Inconel 625 is a solid-solution strengthened alloy, precipitation of secondary phases occurs in weld overlays. Precipitations were identified as a Laves phase and carbonitrides (Nb, Ti)(C, N).

Open access

Maryam I. S. Alkurdi, Sabiha S. Mustafa and Ján Supuka

Abstract

The study of vegetative propagation of the Vitex agnus-castus L., was conducted in the Agriculture College - Salahaddin University field under controlled condition (plastic greenhouse) in two periods (summer time: from 26.5.2008 to 2.9.2008 and winter time: from 15.1.2009 to 28.4.2009). The object of the studies were different soil substrates (sand and river (sharp) sand - sand and peat moss - sand and river (sharp) sand and peat moss). We used two types of stem cuttings (semi-hardwood cuttings „m“ - softwood cuttings „a“). The statistical analysis is based on the experimental project Complete Randomized Design (CRD) with three replications. The results were compared with results from Duncan test at 0.05 level. The study showed that planting in the second period (T2) causes increase in number of branches and leaves, whereas planting in the first period (T1) causes increase in number of roots and root length, the increase in the weight of biomass and dry mass has been observed in the second period of planting (T2). Planting in the sand substrate using semi-hardwood cuttings (m) causes increase in number of branches, leaves, fresh weight, number of roots and root length

Open access

A. Urbańczyk-Gucwa, K. Radwański and K. Rodak

Abstract

The effect of second phase particles on grain refinement in CuFe2 alloy has been investigated by using rolling with the cyclic movement of rolls (RCMR) method. Two different population of second phase particles of Fe: coherent, about 10 nm in diameter and about 100 nm in size were obtained by applying aging treatment followed at 500°C for 2 h and at 700°C for 24 h respectively. In addition, solution treated samples were deformed by RCMR method at the same parameters. The microstructures of the CuFe2 alloy were analyzed using light microscope (LM), electron backscattered diffraction (EBSD) microscope technique and scanning transmission electron microscope (STEM). The presence of high-density of coherent Fe particles in the matrix inhibits recovery process and in the result obtained grain/subgrain boundaries have diffused character and are weakly visible. The largest particles which are not coherent with the matrix act as an effective barrier against the boundary motion.