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On the limits of acoustic emission detectability for twinning

Using synchronized rapid video imaging and calibrated acoustic emission (AE) measurements, a direct correspondence is found between the length of emerging twin and its AE transient response during in-situ testing of Mg polycrystals. The detectability limit for twin nucleation in Mg and its alloys is evaluated to be as small as 0.3 µm or even less. It is shown that the use of appropriate calibratio

Field and laboratory stress-wave measurements of asphalt concrete

Non-contact surface wave measurements are performed on a new asphalt concrete (AC) pavement using 48 micro-electro-mechanical system (MEMS) sensors as receivers to estimate the real part of the dynamic moduli of the AC top layer. Laboratory measurements of core samples, extracted from the field measurement positions, are used to construct master curves for comparison with the field measurements. T

Effect of ion implantation on the physical and mechanical properties of Ti-Si-N multifunctional coatings for biomedical applications

In the present work, multifunctional Ti-Si-N coatings have been deposited using CAVD method with the aim of studying their chemical, physical, structural and mechanical properties. Coatings of Ti-Si-N were modified by high-intensity ion implantation using copper ions with dose D = 2 × 1017 ions/cm2 and energy E = 60 keV. The results demonstrated that ion implantation has an effect on the grain siz

Simulation of microstructural evolution during repair welding of an IN718 plate

A precipitate evolution model based on classical nucleation, growth and coarsening theory is adapted and solved using the multi-class approach for the superalloy IN718. The model accounts for dissolution of precipitates and is implemented in a finite element program. The model is used to simulate precipitate evolution in the fused zone and the adjacent heat affected zone for a welding simulation.

Atomic-level mechanisms of magnesium oxidation

Magnesium has been recently becoming an increasingly popular material for various applications. However, excessive chemical reactivity, and oxidation rate in particular, is a major obstruction on the way of Mg to become widely adopted. A significant problem causing the lack of Mg reactivity control is insufficient understanding of mechanisms involved in the oxidation of magnesium surface. Herewith

Features of twist extrusion : Method, structures & material properties

During the last decade it has been shown that severe plastic deformation (SPD) is a very effective for obtaining ultra-fine grained (UFG) and nanostructured materials. The basic SPD methods are High Pressure Torsion (HPT) and Equal Channel Angular Extrusion (ECAE). Recently several new methods have been developed: 3D deformation, Accumulative Roll Bonding, Constrained Groove Pressing, Repetitive C

A field study of fluorescent and LED classroom lighting

Indoor lighting is facing a massive retrofit to LED lighting. Research is needed to assess whether LED-based lighting can promote energy efficiency, boost visual comfort and support biological functions. This field study considered the lighting of four identical classrooms in an upper secondary school in Helsingborg, Sweden. Two classrooms were fitted with state-of-the-art ceiling pendants contain

Designing online support for families living with depression.

Families living with mental illness experience an added burden and may experience such psychological distress that they require therapeutic intervention. The Internet is used as a daily tool by a growing share of the population worldwide, including for health related matters. Its potential as a health care tool, including advantages and drawbacks, should be explored. The overall aim of the present

Global, regional, and national incidence, prevalence, and years lived with disability for 310 diseases and injuries, 1990-2015 : a systematic analysis for the Global Burden of Disease Study 2015

BACKGROUND: Non-fatal outcomes of disease and injury increasingly detract from the ability of the world's population to live in full health, a trend largely attributable to an epidemiological transition in many countries from causes affecting children, to non-communicable diseases (NCDs) more common in adults. For the Global Burden of Diseases, Injuries, and Risk Factors Study 2015 (GBD 2015), we