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

Thermal analysis and microscopic characterisation of the Al-20%Mg2Si in-situ composite

Al-Mg2Si is an in-situ composite composed of aluminium, magnesium and silicon elements. The reinforcement of Mg2Si crystal structure occurs due to very small solid solubility of Si into Mg. This material is becoming an attractive candidate to manufacture most of industrial products especially automotive and aerospace components. In this research paper, four different phase reactions were detected under slow solidification of base alloy by computer-aided cooling curve thermal analysis (CA-CCTA). Backscattered electron (BSE) imaging and elemental mapping revealed that those phase evolutions corresponded to the formation of primary Mg2Si reinforcement particle, Al-Mg2Si eutectic, Si eutectic and Iron intermetallic respectively

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

Effects of quenching media on phase transformation characteristics and hardness of Cu-Al-Ni-Co shape memory alloys

This paper presents the investigation on the effects of various thermal treatments and quenching media on the phase transformation behaviour of Cu-Al-Ni-Co shape memory alloys (SMAs). The transformation temperatures were determined using a differential scanning calorimeter. The variation of cooling rates had a consequential effect on the phase transformation characteristics of the Cu-Al-Ni-Co SMAs. Nevertheless, the transformation temperature peaks were varied in terms of location as well as heat flow. The results indicated that there was an improvement in transformation temperatures whenever ice water was used as quenching medium. It was also observed that the forward transformation temperatures were higher than the reverse transformation. It was verified that the required heat for the transformation of martensite into austenite was more than the transformation of austenite into martensite. Moreover, thermodynamic parameters, such as enthalpy and entropy, tended to decrease and increase as a result of the changes in the cooling rates of each medium. To clarify the variations of the structures and properties of Cu-Al-Ni-Co SMA quenched samples, x-ray diffraction, atomic force microscopy, field emission scanning electron microscopy, energy dispersive spectroscopy, and Vickers hardness were used