Towards an improved understanding of plasticity, friction and wear mechanisms in precipitate containing AZ91 Mg alloy

This work reports a combined experimental and atomistic simulation study on continuous precipitates (CPs) and discontinuous precipitates (DPs) affecting the scratch induced wear in AZ91 magnesium alloy. Nanoscratching experiments complemented by atomic simulations were performed to understand the directional dependence and origins of plasticity, friction and wear mechanisms as benchmarked to nanocrystalline HCP magnesium. Post scratch deformation analysis was performed using electron back scattering diffraction, scanning electron microscope and molecular dynamics (MD) simulation. The direction of orientation of the precipitates was observed to make a significant influence on the deformation behaviour. For example, regardless of the precipitates type (CP or DP), a ductile-brittle transition becomes pronounced while scratching along the direction (orientation) of precipitates, whilst a fully ductile response was obtained while scratching along the direction normal to the precipitates. However, regardless of the direction of orientation, DPs showed a higher wear resistance and coefficient of friction compared to the CPs. These observations were supported by the quantitative analysis of the planar defects such as coherent twins, extrinsic and intrinsic stacking faults in the deformation zone as well as 1/3〈11¯00〉" role="presentation"> ( and 1/3〈12¯10〉" role="presentation"> dislocations type extracted from the MD analysis.These observations will facilitate an improved design of AZ91 alloys in particular and intermetallic precipitate containing alloys in general

A new synthetic approach to 8-aza analogs of prostaglandins

A new synthetic approach to (dl)-8-aza-13,14-dihydroprostanoic acid and its corresponding ll-hydroxy derivative is described

Metal-insulator transitions in tetrahedral semiconductors under lattice change

Although most insulators are expected to undergo insulator to metal transition on lattice compression, tetrahedral semiconductors Si, GaAs and InSb can become metallic on compression as well as by expansion. We focus on the transition by expansion which is rather peculiar; in all cases the direct gap at $\Gamma$ point closes on expansion and thereafter a zero-gap state persists over a wide range of lattice constant. The solids become metallic at an expansion of 13 % to 15 % when an electron fermi surface around L-point and a hole fermi surface at $\Gamma$-point develop. We provide an understanding of this behavior in terms of arguments based on symmetry and simple tight-binding considerations. We also report results on the critical behavior of conductivity in the metal phase and the static dielectric constant in the insulating phase and find common behaviour. We consider the possibility of excitonic phases and distortions which might intervene between insulating and metallic phases.Comment: 12 pages, 8 figure

Methods of obtaining smooth surface in 2D/3D surface reconstruction

Surface reconstruction is an emergent research area in the field of computer aided design and manufacturing. There are various methods / algorithms which are working considerably well for surface reconstruction problem but we cannot say to the best of our knowledge that we got all the solutions. Missing surface can be repaired either by surface patch or by extending boundary curves. However, in both cases, surface smoothening problem arises in form of flat surface. The present paper has been tried to offer a solution to above problem which makes the curve smoother

Feminist mobilisation for policy change on violence against women: insights from Asia

This article explores how women’s movements in China, India and Indonesia have mobilized to influence processes of legal reform on violence against women (VAW). Legal change is a complex and iterative process, in which both state and non-state actors negotiate and bargain over the content of law in the ‘policy space’, bringing different interests and needs to bear. The three countries featured here differ in many ways, including population size, political system (including varying levels and degrees of democratization and decentralization, and regional and local autonomy), and diversity in the population, including ethnicities and religions. A comparative study such as this offers important potential for understanding policy change on VAW, the role of women’s movements in this, and the obstacles to change

Topical application of substance P promotes wound healing in streptozotocin-induced diabetic rats

a b s t r a c t Substance P (SP) is known to stimulate angiogenesis, fibroblasts proliferation and expressions of cytokines and growth factors involved in wound healing. However, SP level reduces in dermis in diabetics and, hence, it was hypothesized that exogenously applied SP could be helpful in improving wound healing in diabetic rats. Excision skin wound was created on the back of diabetic rats and rats were divided into three groups i.e. (i) saline-, (ii) gel-and (iii) SP-treated. Normal saline, pluronic gel and SP (10 À6 M) in gel were topically applied once daily for 19 days. SP treatment significantly increased the wound closure, levels of interleukin-10, and expressions of vascular endothelial growth factor, transforming growth factor-beta1, heme oxygenase-1 and endothelial nitric oxide synthase, whereas it significantly decreased the expression of tumor necrosis factor-alpha, interleukin-1beta and matrix metalloproteinases-9 in the granulation/healing tissue. The inflammatory cells were present for long time in normal saline-treated group. Histological evaluation revealed better extracellular matrix formation with marked fibroblast proliferation and collagen deposition in SP-treated group. Early epithelial layer formation, increased microvessel density and greater growth associated protein-43 positive nerve fibers were also evidenced in SP-treated group. In conclusion, SP treatment markedly accelerated cutaneous wound healing in diabetic rats

Cooling rate effects on the structure of 45S5 bioglass: Insights from experiments and simulations

Due to its ability to bond with living tissues upon dissolution, 45S5 bioglass and related compositions materials are extensively used for the replacement, regeneration, and repair of hard tissues in the human body. However, the details of its atomic structure remain debated. This is partially due to the non-equilibrium nature of glasses, as their non-crystalline structure is highly dependent on their thermal history, namely, the cooling rate used during quenching. Herein, combining molecular dynamics (MD) simulations with cooling rates ranging over several orders of magnitude and experimental studies using nuclear magnetic resonance (NMR), we investigate the structure of the nominal 45S5 bioglass composition. These results suggest that the MD simulation results when extrapolated to experimental cooling rates can provide a reasonable estimate of the structure of 45S5 bioglass. Finally, based on these results, we suggest the propensity of the phosphate group to form isolated orthophosphate species. Overall, these results reconcile the simulation and experimental results on the structure of 45S5 bioglass, and particularly on the speciation of the phosphate group, which may be key in controlling the bioactivity of 45S5 bioglass

Co-Creation of Breast Cancer Risk Communication Tools and an Assessment of Risk Factor Awareness: A Qualitative Study of Patients and the Public in India

The incidence of breast cancer (BC) is increasing worldwide, and India reported 179,790 cases in 2020. It is important to inform people of risk factors and methods for risk management through interactive risk communication techniques. Affordable, easy-to-understand transmedia tools for the communication of BC risk were co-created by a multidisciplinary team of doctors, clinical researchers, epidemiologists, health economists, digital designers, and public representatives. Qualitative in-depth interviews were conducted in regional languages to assess the views of patients, relatives, the public, and health professionals in India of these prototypes. There was low awareness of BC, with some understanding of age and hereditary risk factors but limited knowledge of reproductive factors amongst the general public, patients, and relatives. Participants favored storytelling techniques (animation and comic strips/infographics) to explain complex issues such as genetic risk and testing. Co-created BC risk communication transmedia tools should be used to support informed decision making