Deformation twinning during high temperature compression tests of the Ni-base superalloy ATI 718Plus®

This study discusses the deformation mechanisms active during high temperature compression tests of the Ni-base superalloy ATI 718Plus R. Deformation twins were observed in deformed grains across a range of temperatures and strain rates by use of transmission electron microscopes (TEM). Even at strain rates as low as 0.01 s-1 and temperatures up to 1025C the microstructure contained of grains which deformed by deformation twinning. It was concluded that the low stacking fault energy of the alloy, which was measured to be 15mJm-2 caused the formation of the deformation twins. In addition, several examples of the early stages of twin formation were captured. The twinning partials were in most cases emitted from grain boundaries. In a second instance cross-slip events from a Frank-Read source lead to the formation of partials which formed stacking faults

Editorial: Grazing in future multi-scapes: From thoughtscapes to landscapes, creating health from the ground up

More than half the land surface of the Earth is used for grazing (United Nations General Assembly, 2022), with Asia at 36% and Africa at 30% of the total. About 91% of global grass- and range-lands are unfenced with few boundaries and limited crop farming (Reid et al., 2014). The remaining grass- and range-lands are privately owned and used, with 13% in North America, 10% in Australia and New Zealand, 8% in South America, and 3% in Europe; all with a mix of more intensive grazing and cultivated land. No wonder why across the world's landscapes, grazing and browsing herbivores—both wild and livestock—(be they within a spatial and temporal pastoral context, whether they naturally graze or are grazed by farmers, ranchers, shepherds, and nomadic peoples—all termed pastoralists), fulfill essential roles in driving the composition, structure, and dynamics of pastoral ecosystem. The provision of ecosystem services, including social, economic, and cultural benefits to families, farms, and communities, is accordingly impacted (Gregorini, 2015)

Intracellular trafficking and cellular uptake mechanism of PHBV nanoparticles for targeted delivery in epithelial cell lines

Indexación: Web of Science; Scopus; Scielo.Background: Nanotechnology is a science that involves imaging, measurement, modeling and a manipulation of matter at the nanometric scale. One application of this technology is drug delivery systems based on nanoparticles obtained from natural or synthetic sources. An example of these systems is synthetized from poly(3-hydroxybutyrate-co-3-hydroxyvalerate), which is a biodegradable, biocompatible and a low production cost polymer. The aim of this work was to investigate the uptake mechanism of PHBV nanoparticles in two different epithelial cell lines (HeLa and SKOV-3). Results: As a first step, we characterized size, shape and surface charge of nanoparticles using dynamic light scattering and transmission electron microscopy. Intracellular incorporation was evaluated through flow cytometry and fluorescence microscopy using intracellular markers. We concluded that cellular uptake mechanism is carried out in a time, concentration and energy dependent way. Our results showed that nanoparticle uptake displays a cell-specific pattern, since we have observed different colocalization in two different cell lines. In HeLa (Cervical cancer cells) this process may occur via classical endocytosis pathway and some internalization via caveolin-dependent was also observed, whereas in SKOV-3 (Ovarian cancer cells) these patterns were not observed. Rearrangement of actin filaments showed differential nanoparticle internalization patterns for HeLa and SKOV-3. Additionally, final fate of nanoparticles was also determined, showing that in both cell lines, nanoparticles ended up in lysosomes but at different times, where they are finally degraded, thereby releasing their contents. Conclusions: Our results, provide novel insight about PHBV nanoparticles internalization suggesting that for develop a proper drug delivery system is critical understand the uptake mechanism.https://jnanobiotechnology.biomedcentral.com/articles/10.1186/s12951-016-0241-

On direct measurement of the W production charge asymmetry at the LHC

The prospects for making a direct measurement of the W production charge asymmetry at the LHC are discussed. A modification to the method used at the Tevatron is proposed for measurements at the LHC. The expected sensitivity for such a measurement to parton distribution functions is compared to that for a measurement of the lepton charge asymmetry. The direct measurement approach is found to be less useful for placing constraints on parton distribution functions at the LHC than a measurement of the lepton charge asymmetry.Comment: 18 pages, 10 figures, v2: references and keywords updated v3: Additional paragraph discussing inclusion of W asymmetry in global fits adde

Finite Schur filtration dimension for modules over an algebra with Schur filtration

Let G be GL_N or SL_N as reductive linear algebraic group over a field k of positive characteristic p. We prove several results that were previously established only when N 2^N. Let G act rationally on a finitely generated commutative k-algebra A. Assume that A as a G-module has a good filtration or a Schur filtration. Let M be a noetherian A-module with compatible G action. Then M has finite good/Schur filtration dimension, so that there are at most finitely many nonzero H^i(G,M). Moreover these H^i(G,M) are noetherian modules over the ring of invariants A^G. Our main tool is a resolution involving Schur functors of the ideal of the diagonal in a product of Grassmannians.Comment: 22 pages; final versio

Bifurcation Boundary Conditions for Switching DC-DC Converters Under Constant On-Time Control

Sampled-data analysis and harmonic balance analysis are applied to analyze switching DC-DC converters under constant on-time control. Design-oriented boundary conditions for the period-doubling bifurcation and the saddle-node bifurcation are derived. The required ramp slope to avoid the bifurcations and the assigned pole locations associated with the ramp are also derived. The derived boundary conditions are more general and accurate than those recently obtained. Those recently obtained boundary conditions become special cases under the general modeling approach presented in this paper. Different analyses give different perspectives on the system dynamics and complement each other. Under the sampled-data analysis, the boundary conditions are expressed in terms of signal slopes and the ramp slope. Under the harmonic balance analysis, the boundary conditions are expressed in terms of signal harmonics. The derived boundary conditions are useful for a designer to design a converter to avoid the occurrence of the period-doubling bifurcation and the saddle-node bifurcation.Comment: Submitted to International Journal of Circuit Theory and Applications on August 10, 2011; Manuscript ID: CTA-11-016

Communicating risk from the frontline: projecting community voices into disaster risk management policies across scales, in: Urban Ark Briefing No 19. October 2018

Research carried out in Dar es Salaam, Tanzania on cross-scalar risk communication and disaster risk governance reveals that, while there is considerable potential for communities to measure and communicate risk and to prioritise actions, there is little scope for them to influence disaster risk governance at this point in time. This is partly because, although disaster risk management (DRM) is devolved in Tanzania, it has not gone far enough to give adequate powers and financing to the lowest level of government at the sub-wards, which are at the frontline of managing the biggest everyday risks that people face. The effective communication of risks upwards from communities to governments, and of DRM policies and opportunities downwards to communities and across sectors is crucial to overcome these gaps. When communication is participatory and collaborative, there is scope for local city actors to reflect on the need for action to be joined across governance scales, and to ensure communication plays a key role at and between all levels

Fatigue analysis-based numerical design of stamping tools made of cast iron

This work concerns stress and fatigue analysis of stamping tools made of cast iron with an essentially pearlitic matrix and containing foundry defects. Our approach consists at first, in coupling the stamping numerical processing simulations and structure analysis in order to improve the tool stiffness geometry for minimizing the stress state and optimizing their fatigue lifetime. The method consists in simulating the stamping process by considering the tool as a perfect rigid body. The estimated contact pressure is then used as boundary condition for FEM structure loading analysis of the tool. The result of this analysis is compared with the critical stress limit depending on the automotive model. The acceptance of this test allows calculating the fatigue lifetime of the critical zone by using the S–N curve of corresponding load ratio. If the prescribed tool life requirements are not satisfied, then the critical region of the tool is redesigned and the whole simulation procedures are reactivated. This method is applied for a cast iron EN-GJS-600-3. The stress-failure (S–N) curves for this material is determined at room temperature under push pull loading with different load ratios R0σmin/σmax0−2, R0−1 and R00.1. The effects of the foundry defects are determined by SEM observations of crack initiation sites. Their presence in tested specimens is associated with a reduction of fatigue lifetime by a factor of 2. However, the effect of the load ratio is more important