1,773,398 research outputs found
Osteoindctivization of dental implants and bone- defect-filling materials
No full texthttp://www.woodheadpublishing.com/en/book.aspx?bookID=159
CMAS corrosion of EB PVD TBCs: Identifying the minimum level to initiate damage
Get PDFOver the last decade a significant amount of research has been conducted into
the durability of thermal barrier coatings (TBCs) focusing mainly on issues of
oxidation, erosion and foreign object damage (FOD). However, as the performance
and durability of TBCs has improved the temperatures at which they operate has
increased. This increase in temperature has resulted in another lifing issue for
EB PVD TBCs, namely that of CMAS attack. Calciumâ  magnesiumâ  alumino-silicate
(CMAS) attack occurs when atmospheric dust that has deposited on the surface of
turbine blades melts and wicks into the columns of the TBC. This occurs at
temperatures above 1240â  1260 à °C and results in the degradation of the
columnar microstructure of the TBCs. Due to the fact that TBCs operate in a
temperature gradient CMAS only infiltrates part of the coating before
solidifying. There are a number of issues associated with CMAS attack, both
chemical and mechanical. From a chemical point of view CMAS attack of electron
beam (EB) physical vapour deposited (PVD) TBCs can be considered as a form of
corrosion; when there is a lot of excess CMAS on the surface of a coated
component Yttria diffuses out of the TBC into the molten CMAS resulting in a
tâ ² to monoclinic phase transformation in the yttria stabilised zirconia (YSZ),
CMAS attack also results in localised melting and subsequent re-precipitation of
the coating resulting in a loss of the defined columnar microstructure. While
from a mechanical point of view the CMAS, once re-solidified, reduces the strain
compliance of the EB PVD and can result in spallation of the TBC on cooling.
Furthermore, current studies have indicated that small amount of CMAS
infiltration significantly increases the erosion rate of EB PVD TBCs. This paper
covers various aspects of CMAS attack of EB PVD TBCs, specifically looking at
minimum levels of CMAS required to initiate damage, as well as investigating it
from an erosionâ  corrosion
EB-NPCs are significantly different than our previously differentiated NPCs.
No full textEB-NPCs cluster away from both pluripotent stem cells and NPCs derived from both ESCs and iPSCs by our previously published method in both (A) Principal component analysis and (B) hierarchical clustering. (C) EB-NPCs show a lack of TGFβ2 transcript as shown by whole genome expression analysis.</p
EB-derived erythrocytes are uniformly of the primitive lineage.
No full textA) Single-cell RT-PCR (Biomark System, Fluidigm) from FACS-sorted primary and EB-derived erythroid cells as indicated in the colour coded groups for embryonic (Hba-x and Hbb-y) and adult (Hba-a1/2 and Hbb-b1/2) globin genes. B) PCA of expression data from a panel of 40 probes used for single-cell RT-PCR (Biomark System, Fluidigm) to distinguish primitive and definitive lineages of specific differentiation stages. EB-derived erythroid cells (dark and light blue dots) most closely resemble E9.5 primary cells (orange circles with a black outline) as indicated with the black dotted circle.</p
Preprosthetic and maxillofacial surgery: Biomaterials, bone grafting and tissue engineering
No full textA Német Fürjész eb alkalmazhatósága hazánkban
No full textA Német Fürjész eb mint hazánkban ritkának számító kutya fajta jellemzése, fajtaleírása, standardje. A különböző vadászterületeken történő alkalmazása, eredményessége. A különböző minősítések, vizsgakövetelmények leírásai. A fajta ajánlás mindazoknak akik szeretik a vadászatot, illetve vadászathoz egy kutyát szeretnének használni, valamint meglátják az értéket a kutyában. Összehasonlítás más német vadászkutyákkal.vadgazda mérnökBSc/B
Supplementary Figure 7 from <sup>177</sup>Lu-DOTA-EB-TATE, a Radiolabeled Analogue of Somatostatin Receptor Type 2, for the Imaging and Treatment of Thyroid Cancer
No full textSupplemental Figure 7: VAC treatment did not improve therapeutic efficacy of DOTA-EB-TATE in either low- or high-SSTR2 expressing tumors. (A) No effect of VAC on the tumor progression in the 177Lu-DOTA-EB-TATE treated FTC133 (low-SSTR2-expressing) subcutaneous xenograft mice model. C-control mice that received 177Lu-DOTA-EB-TATE (n=8); VAC-valproic acid treated mice that received 177Lu-DOTA-EB-TATE (n=9). Data are presented as mean{plus minus}SEM. (B) No effect of VAC on the tumor progression in the 177Lu-DOTA-EB-TATE treated AR42J (high-SSTR2-expressing) subcutaneous xenograft mice model. C-control mice that received 177Lu-DOTA-EB-TATE (n=8); VAC-valproic acid treated mice that received 177Lu-DOTA-EB-TATE (n=7). Data are presented as mean{plus minus}SEM.</p
The processing windows for NiTi alloy manufactured by PBF-EBessing windows for NiTi alloy manufactured by PBF-EB
No full textNickel titanium (NiTi) as one of the most utilized shape memory alloy has drawn significant interest due to its unique characteristics. However, NiTi is also considered a susceptible material to smoke during electron beam powder bed fusion (PBF-EB) process, which restricts the manufacturing possibility of the components. This work investigates processing windows for pre-heating and melting of NiTi powder to allow fabricating healthy parts. The smoke tests were carried out at different focus offsets and beam currents in relation to beam speeds. It is noted that a smaller EB spot can effectively prevents smoking while it may cause the strong powder bonding which can affect powder recycling negatively. Thus, a less focused beam (or larger EB spot) was selected to reach medium but efficient sintering. Moreover, it was observed that a negative defocused EB mitigates the smoke phenomenon compared to the positive defocused EB with a similar spot size. After that, parts having a relative density over 99% were successfully manufactured with PBF-EB. It is also found that with the same level of energy input, a set of low power with low scan speed leads to denser parts compared to a set of high power with high scan speed. This is attributed to less complexities in the melt dynamic which is related to lower density of impacting electrons. Besides, the combination of low power with low scan speed also improves geometrical accuracy of the parts attributed to the smaller spot size and smaller melt pool sizes. </p
Development of EB-PVD TBC'S : the role of deposition temperature and plasma assistance
No full textGas turbine manufacturers have achieved continuingly improved engine
efficiency and thrust-to-weight ratio by designing with increased Turbine
Entry Temperature (TET). The protection of High Pressure Turbine (HPT)
aerofoils with thin insulating ceramic coatings, referred to as Thermal Barrier
Coatings (TBC's), has emerged as the next key technology to allow for further
increases in TET. Electron Beam Physical Vapour Deposition (EB-PVD) is
today's most promising processing route for the manufacture of TBC's applied
on aerofoils.
The purpose of this work was to generate a sound understanding of the
relationship between the EB-PVD process and the structure of Zr02-
8wt%Y2O3 ceramic deposits, which could be exploited to achieve improved
TBC performance. In particular, the role of deposition temperature and the
potential benefits in using RF and DC plasma assistance of the EB-PVD
process were investigated, together with their influence on the erosion
performance of EB-PVD TBC's. The significance of particulate erosion as a
degradation mode is assessed under conditions representative of the HPT
environment. New explorable routes to achieve reduced thermal conductivity
of EB-PVD TBC's are identified.
It is shown that EB-PVD TBC's deposited at low temperature contain a
massive content of microscopic voidage (-50%) which is responsible for their
lack of thermal stability. The growth of EB-PVD TBC's at elevated deposition
temperatures is explained in terms of dynamic sintering, whereby diffusion
processes compete against the high rate arrival of vapour atoms to overcome
the spontaneous defectiveness of the atomic build up. Modelling of the gas
discharge physics has highlighted scope for improving the effectiveness of
plasma assistance in causing ceramic structural damage, capable of modifying
the coating thermal properties.
The erosion rate of EB-PVD TBC's is shown to be controlled by their degree
of plastic deformation upon particle impacts, which in turn depends on the
ceramic column diameter and inherent porosity
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