Crystal structure changes in Ni3Al and its anomalous temperature dependence of strength

The existence of a structural transformation in Ni3Al alloys established earlier through X-ray diffraction, dilatometry and TEM investigations are summarised. The results obtained are discussed through a model proposed. The L12 structure appears to transform to another L12 or to a DO22 structure during heating. Such a transformation starts at around 700°C and seems to complete around 1100°C. In the temperature range 700-1100°C both phases coexist. This causes a tetragonal distortion of the L12 lattice giving rise to a tweed morphology in TEM observations. The flow stress studies indicate that the anomalous strengthening behaviour is not only due to the dislocation kind of mechanism as proposed in the literature but also due to the structural changes noticed in this work

Teacher Allocation and Equity in Malaysian Schools

Although inequalities in education are relatively well researched, little attention is given to the inequalities in the educational resources used in education. This is clearly a shortcoming in the course of providing equitable education to all. One of the educational resources frequently used in discussion is teachers. Other than being very mobile, teachers are often used as proxy for educational resources because of their role and importance in educating a child. However, not many researchers have evaluated them/this resource in terms of availability in a school. In this paper, allocation of trained teachers to schools is measured. Using Malaysian data from 1986-2006 and Gini coefficient, a well known measure of distribution, trends and patterns of equity are examined. By estimating the Gini coefficient, we aim to enhance our understanding of resource inequalities and their drivers. Inequity is examined at two levels of education, i.e. primary schools and secondary schools. Initial results reveal that the level of equity in primary schools is less desirable than in secondary schools. In this paper, possible reasons on this outcome are delved into.- education, teachers, equity, Gini coefficient

Incorporating Local Water Quality in Welfare Measures of Agri-environmental Policy: A Choice Modelling Approach Employing GIS

The spatial distribution of agro-environmental policy benefits has important implications for the efficient allocation of management effort. The practical convenience of relying on sample mean values of individual benefits for aggregation can come at the cost of biased aggregate estimates. The main objective of this paper is to test spatial hypotheses regarding respondents’ local water quality and quantity, and their willingness-to-pay for improvements in water quality attributes. This paper combines choice experiment and spatially related water quality data via a Geographical Information System (GIS) to develop a method that evaluates the influence of respondents’ local water quality on willingness-to-pay for river and stream conservation programs in Canterbury, New Zealand. Results show that those respondents who live in the vicinity of low quality waterway are willing to pay more for improvements relative to those who live near to high quality waterways.Water Quality, Choice Experiment, Geographical Information System, Environmental Economics and Policy, Resource /Energy Economics and Policy, Q51, Q25, Q58,

A Circle Has No End: Role of Cyclic Topology and Accompanying Structural Reorganization on the Hole Distribution in Cyclic and Linear Poly‑p‑phenylene Molecular Wires

π-Conjugated organic oligomers/polymers hold great promise as long-range charge-transfer materials for modern photovoltaic applications. However, a set of criteria for the rational design of functional materials is not yet available, in part because of a lack of understanding of charge distribution in extended π-conjugated systems of different topologies, and concomitant effects on redox and optical properties. Herein we demonstrate the role of cyclic versus linear topology in controlling the redox/optical properties and hole distribution in poly-p-phenylenes (PPs) with the aid of experiment, computation, and our recently developed multistate parabolic model (MPM). It is unequivocally shown that the hole distribution in both cyclic and linear poly-p-phenylene (n ≥ 7) cation radicals is limited to seven p-phenylene units, despite the very different topologies. However, the effect of topology is evidenced in the very different trends in oxidation potentials of cyclic versus linear PPs, which are shown to originate largely from the geometrical distortion of individual p-phenylene units in cyclic PPs. The presence of additional pairwise electronic coupling element in cyclic PPs, absent in linear PPs, plays a significant role only in smaller cyclic PP5 and PP6. This study provides a detailed conceptual description of cyclic and linear poly-p-phenylene cation radicals and demonstrates the versatility and predictive power of MPM, an important new tool for the design and synthesis of novel and efficient charge-transfer materials for molecular electronics and photovoltaic applications, an area of widespread interest

Significance of thermal fluctuations and hydrodynamic interactions in receptor-ligand mediated adhesive dynamics of a spherical particle in wall bound shear flow

The dynamics of adhesion of a spherical micro-particle to a ligand-coated wall, in shear flow, is studied using a Langevin equation that accounts for thermal fluctuations, hydrodynamic interactions and adhesive interactions. Contrary to the conventional assumption that thermal fluctuations play a negligible role at high P$\acute{e}$clet numbers, we find that for particles with low surface densities of receptors, rotational diffusion caused by fluctuations about the flow and gradient directions aids in bond formation, leading to significantly greater adhesion on average, compared to simulations where thermal fluctuations are completely ignored. The role of wall hydrodynamic interactions on the steady state motion of a particle, when the particle is close to the wall, has also been explored. At high P$\acute{e}$clet numbers, the shear induced force that arises due to the stresslet part of the Stokes dipole, plays a dominant role, reducing the particle velocity significantly, and affecting the states of motion of the particle. The coupling between the translational and rotational degrees of freedom of the particle, brought about by the presence of hydrodynamic interactions, is found to have no influence on the binding dynamics. On the other hand, the drag coefficient, which depends on the distance of the particle from the wall, plays a crucial role at low rates of bond formation. A significant difference in the effect of both the shear force and the position dependent drag force, on the states of motion of the particle, is observed when the P$\acute{e}$let number is small.Comment: The manuscript has been accepted as an article in Physical Review E Journa

DESIGN, ANALYSIS AND FABRICATION OF CANARD WING CONFIGURATION

In aeronautics, canard is an airframe configuration of fixed wing aircraft in which the forward surface is smaller than the rearward, the former being known as the "canard", the aim of this project is to design, analysis and fabricate of the canard wing configuration. The first step in our project we do design of the canard wing configuration and analysis the aerofoil we do take in the design and conduct the 2D flow analysis by putting the canard aerofoil followed by main wing aerofoil by means the flow pattern how seriously affect the main wing. Then we fabricate the canard configuration by placing the canard in the best place that does not affect the main wing flow parameter. A canard design tends to be less controllable than a conventional design because aileron on the main wing may be subject to turbulence from the canards that varies widely at different angle of attack leading to conditions of deep stall. If the ailerons were located on the canards, we used to find the best place where the canard aero foil suits well and it does affect the main wing flow parameter in the cruise speed at high angle attack. Canards have poor stealth characteristics because they present large, angular surfaces that tend to reflect radar signals