43 research outputs found
Redefining genomic privacy: trust and empowerment
Fulfilling the promise of the genetic revolution requires the analysis of large datasets containing information from thousands to millions of participants. However, sharing human genomic data requires protecting subjects from potential harm. Current models rely on de-identification techniques in which privacy versus data utility becomes a zero-sum game. Instead, we propose the use of trust-enabling techniques to create a solution in which researchers and participants both win. To do so we introduce three principles that facilitate trust in genetic research and outline one possible framework built upon those principles. Our hope is that such trust-centric frameworks provide a sustainable solution that reconciles genetic privacy with data sharing and facilitates genetic research
Minding rights: Mapping ethical and legal foundations of ‘neurorights’
The rise of neurotechnologies, especially in combination with artificial intelligence (AI)-based methods for brain data analytics, has given rise to concerns around the protection of mental privacy, mental integrity and cognitive liberty – often framed as “neurorights” in ethical, legal, and policy discussions. Several states are now looking at including neurorights into their constitutional legal frameworks, and international institutions and organizations, such as UNESCO and the Council of Europe, are taking an active interest in developing international policy and governance guidelines on this issue. However, in many discussions of neurorights the philosophical assumptions, ethical frames of reference and legal interpretation are either not made explicit or conflict with each other. The aim of this multidisciplinary work is to provide conceptual, ethical, and legal foundations that allow for facilitating a common minimalist conceptual understanding of mental privacy, mental integrity, and cognitive liberty to facilitate scholarly, legal, and policy discussions
Microstructure characterization, mechanical, and tribological properties of slow-cooled Sb-treated Al-20Mg2Si-Cu in situ composites
Role of Sb addition on structural characteristics, mechanical properties, and wear behavior of Al-20Mg2Si-Cu in situ composite under slow cooling condition was thoroughly investigated in this study using stereomicroscopy, optical and scanning electron microscopy, thermal analysis, tensile, impact, hardness tests, and wear tester. Results show that addition of 0.8 wt.% Sb was found to produce a change in the morphology of primary Mg2Si from dendrite to fine polygonal shape. At this Sb addition, the primary Mg2Si phase also exhibited a reduction in size from 179.4 to 128.6 μm, an increase in density of Mg2Si per area from 12.5 to 32.2 particle/mm2, and a decrease in the aspect ratio from 1.24 to 1.11. Increasing the amount of Sb added up to 1 wt.% also resulted in a decrease in both nucleation and growth temperatures of the eutectic Mg2Si by 2.6 and 1.7 °C respectively, which is most likely due to change of eutectic Mg2Si morphology from flake to fibrous structure. Thermal analysis technique showed that distribution of Mg2Si particles influences the heat conductivity during the solidification process of Al-Mg2Si composite. The results also showed that improvements in mechanical properties of composite were obtained with increasing Sb content due to modification of both primary and eutectic Mg2Si and due to intermetallic compound transformation from β-Al5FeSi to α-Al15(Fe,Mn)3Si2. Examination of fracture surfaces from tensile and impact samples showed that the base composite failed in a brittle manner with decohered or debonded Mg2Si particles, whereas the 0.8 wt.% Sb-treated composite showed more cracked Mg2Si and ductile fracture in the matrix. Wear properties improved significantly with addition of Sb due to modification and better dispersion of fine Mg2Si particles in matrix
Effect of modifier elements on machinability of Al-20Mg2Si metal matrix composite during dry turning
The principle aim of this study was to observe the effect of machining parameters as well as the separate additions of 0.4 wt% bismuth, 0.01 wt% strontium, and 0.8 wt% antimony on the machinability of Al-20%Mg2Si in situ metal matrix composite. Microstructure alteration, surface roughness, main cutting force, and chip morphology were taken into account as indices to examine the effect of modifiers and machinability during dry turning. It was found that the additives modify the Mg2SiP particles by changing the particle shape from coarse primary to polygonal shape and decrease the particle size and aspect ratio as well as increase the particle density. Results show that the modified work-pieces present adequate machinability with respect to cutting force and surface roughness. The smaller reinforcements enable lower surface roughness values to be obtained even if they are pulled out, fractured, or elongated. In addition, the modified work-pieces encourage lower surface roughness values in comparison with unmodified work-piece due to less built-up-edge formation. A scenario for surface roughness of Al-Mg2Si composite with respect to the size and aspect ratio of reinforcement particles is proposed in this study
Microstructure development, phase reaction characteristics and mechanical properties of a commercial Al-20%Mg<inf>2</inf>Si-xCe in situ composite solidified at a slow cooling rate
The microstructure, phase reaction characteristics and mechanical properties of fabricated Al–20%Mg2Si in situ composite with different contents of cerium have been investigated using optical microscopy, scanning electron microscopy, X-ray diffraction, thermal analysis and hardness tests. The results show that addition of Ce not only refined Mg2Si reinforcement particles but also changed the morphology of eutectic Al–Mg2Si, Al5FeSi (β) intermetallic and Al5Cu2Mg8Si6 (Q) + Al2Cu (Ɵ) phases. It was found that 0.8 wt% Ce is the optimum concentration to transform the phases into refined structures. The structure of the skeleton of Mg2SiP changed to a polygonal shape with uniform distribution and decrease in size from 124 μm to 60 μm and increased in density from 12 to 45 particles/mm2. Flake-like Mg2SiE transformed into a rod-like morphology. In addition, the aspect ratio of needle-like β structures reduced from 40.5 to 22.9, accompanied with an increase of solid fraction for Q + Ɵ phase. Ce addition increased the nucleation temperature of Mg2SiP and β phases; however, it had an opposite effect for the Mg2SiE and Q + Ɵ phases. The composite hardness increased from 61.32 to 74.15 HV because of refinement of the microstructure. The refining mechanism of Mg2SiP and Mg2SiE phases is discussed in the current study, and formation of new Ce compounds is believed to be responsible for the refinement effect
Effect of primary and eutectic Mg2Si crystal modifications on the mechanical properties and sliding wear behaviour of an Al–20Mg2Si–2Cu–xBi composite
This work investigated the microstructure evolution, tensile, impact, hardness, and sliding wear properties of an Al–20Mg2Si–2Cu in situ composite treated with different Bi contents. The desired modification of primary Mg2Si particles was achieved with the addition of 0.4 wt% Bi. Increasing Bi beyond 0.4 wt% resulted in a loss of modification, possibly due to the formation of Al8MgBiSi4 compound before the precipitation of the primary Mg2Si. Additionally, the structure of the pseudo-eutectic Mg2Si was transformed from plate to fibrous, which was consistent with decrease of growth temperature extracted from the cooling curve thermal analysis. Addition of Bi had an effect on the morphology of Al5FeSi (β), Al2Cu (θ) and Al5Cu2Mg8Si6 (Q) intermetallic compounds. The tensile strength, elongation percentage, impact toughness, and hardness increased by 6%, 13%, 75%, and 23%, respectively, due to modification of both the primary and eutectic Mg2Si crystals. The tensile and impact fracture surfaces showed fewer decohered particles in the Bi-treated composite. The enhancement in wear resistance of the Bi-treated composite could be attributed to solid lubricant function of insoluble soft Bi phase and modification effects on Mg2Si particles
Effects of cutting condition on surface roughness when turning untreated and sb-treated al-11%si alloys using pvd coated tools
Surface roughness is an important output in different manufacturing processes. Its characteristic affects directly the performance of mechanical components and the fabrication cost. In this current work, an experimental investigation was conducted to determine the effects of various cutting speeds and feed rates on surface roughness in turning the untreated and Sb-treated Al-11%Si alloys. Experimental trials carried out using PVD TIN coated inserts. Experiments accomplished under oblique dry cutting when three different cutting speeds have been used at 70, 130 and 250 m/min with feed rates of 0.05, 0.1 and 0.15 mm/rev, whereas depth of cut kept constant at 0.05 mm. The results showed that Sb-treated Al-11%Si alloys have poor surface roughness in comparison to untreated Al-11%Si alloy. The surface roughness values reduce with cutting speed increment from 70 m/min to 250 m/min. Also, the surface finish deteriorated with increase in feed rate from 0.5 mm/rev to 0.15 mm/rev
Perceptions of nature, nurture and behaviour
Trying to separate out nature and nurture as explanations for behaviour, as in classic genetic studies of twins and families, is now said to be both impossible and unproductive. In practice the nature-nurture model persists as a way of framing discussion on the causes of behaviour in genetic research papers, as well as in the media and lay debate. Social and environmental theories of crime have been dominant in criminology and in public policy while biological theories have been seen as outdated and discredited. Recently, research into genetic variations associated with aggressive and antisocial behaviour has received more attention in the media. This paper explores ideas on the role of nature and nurture in violent and antisocial behaviour through interviews and open-ended questionnaires among lay publics. There was general agreement that everybody’s behaviour is influenced to varying degrees by both genetic and environmental factors but deterministic accounts of causation, except in exceptional circumstances, were rejected. Only an emphasis on nature was seen as dangerous in its consequences, for society and for individuals themselves. Whereas academic researchers approach the debate from their disciplinary perspectives which may or may not engage with practical and policy issues, the key issue for the public was what sort of explanations of behaviour will lead to the best outcomes for all concerned