Influence of thermomechanical loads on the energetics of precipitation in magnesium aluminum alloys

We use first principles calculations to study the influence of thermomechanical loads on the energetics of precipitation in magnesium-aluminum alloys. Using Density Functional Theory simulations, we present expressions of the energy of magnesium-aluminum binary solid solutions as a function of concentration, strain and temperature. Additionally, from these calculations, we observe an increase in equilibrium volume (and hence the equilibrium lattice constants) with the increase in concentration of magnesium. We also observe an increase in the cohesive energy of solutions with increase in concentration, and also present their dependence on strain. Calculations also show that the formation enthalpy of β phase solutions to be strongly influenced by hydrostatic stress, however the formation enthalpy of α phase solutions remain unaffected by hydrostatic stress. We present an expression of the free energy of any magnesium aluminum solid solution, that takes into account the contributions of strain and temperature. We note that these expressions can serve as input to process models of magnesium-aluminum alloys. We use these expressions to report the influence of strains and temperature on the solubility limits and equilibrium chemical potential in Mg-Al alloys. Finally, we report the influence of thermomechanical loads on the growth of precipitates, where we observe compressive strains along the c axis promotes growth of precipiates with a (0001)_α habit plane, whereas strains along the a and b directions do not influence the growth of precipitates

Affine Connections in Quantum Gravity and New Scalar Fields

International audienceIn this manuscript, we will discuss the construction of covariant derivative operator inquantum gravity. We will find it is more perceptive alternative to use affine connections more general than metric compatible connections in quantum gravity. We will demonstrate this using the canonical quantization procedure.This is valid irrespective of the presence and nature of sources. The conventional Palatini and metric-affine formalisms, where the actionsare linear in the scalar curvature with metric and affine connections being the the independent variables, are not much suitable to construct a source-free theory of gravity with general affine connections. This is also valid for many minimally coupled interacting theories where sources only couple with metric by using the Levi-Civita connectionsexclusively. We will discuss potential formalism of affine connections to introduce affine connectionsmore general than metric compatible connections in gravity.We will also discuss possible extensions of the actions for this purpose. General affine connections introduce new fieldsin gravity besides metric. In this article, we will consider a simple potential formalism with symmetric affine connections and symmetric Ricci tensor.Corresponding affine connections introduce only two massless scalar fields.One of these fields contributes a stress-tensor with opposite sign to the sources of Einstein's equationwhen we state the equation using the Levi-Civita connections.This means we have a massless scalar field with negative stress-tensor in Einstein's equation. These scalar fields can be useful to explain dark energy andinflation. These fields bring us beyond strict local Minkowski geometries

Addressing and Solving the problem of Data Authenticity due to Packet Dropping by Selfish Nodes in WSN

Wireless Sensor Networks (WSN) consists of large number sensor nodes. Wireless sensor nodes are generally deployed in the far places like forests deserts and used to sense the network conditions like temperature pressure etc. In such far places it is very difficult to recharge or replace the battery of the sensor node.  The sensor nodes are battery powered devices, they communicate over a wireless medium and consumes energy during data transmission. The various types of active and passive attacks are possible in routing the data from source to sink. In this paper, we propose new technique to prevent these attacks. The mobile sinks is been deployed in the network which collect data from the sensor node and deliver data to fixed base station. In the proposed technique, the data privacy is ensured in the mobile sink. KEYWORDS WSN, Mobile Sinks, Sensor node, Query, batter

Providing Privacy and security of Wireless sensor network using ACTOR nodes

Wireless Sensor Networks (WSN) consists of large number sensor nodes. Wireless sensor nodes are generally deployed in the far places like forests deserts and used to sense the network conditions like temperature pressure etc. In such far places it is very difficult to recharge or replace the battery of the sensor node.  The sensor nodes are battery powered devices, they communicate over a wireless medium and consumes energy during data transmission. The various types of active and passive attacks are possible in routing the data from source to sink. In this paper, we propose new technique to prevent these attacks. The mobile sinks is been deployed in the network which collect data from the sensor node and deliver data to fixed base station. In the proposed technique, the data privacy is ensured in the mobile sink. KEYWORDS WSN, Mobile Sinks, Sensor node, Query, batter

Developing Effective Crowdsourcing Systems for Medical Diagnosis: Challenges and Recommendations

Diverse medical traditions follow different ‘grammar’ making encapsulation of varied body of knowledge challenging. However, the advances in information technology in the 21st century provide an opportunity to aggregate knowledge from varied cultures and medical traditions to tackle difficult health issues for which no cure has been developed. In addition to accumulating knowledge from wide-ranging sources, an ideal crowdsourcing system (CS) can benefit from the use of appropriate algorithms to choose the best solution. This conceptual paper examines existing classification of crowdsourcing and the various challenges involved with the capture and transmission of medical knowledge. It proposes the steps involved in developing an effective CS for dealing with medical problems. The ideal CS should involve the crowd and medical experts from all across the world, who together with the help of algorithms and other technology features in the CS could provide a useful solution for hard to solve health problems