Effect of β/α Strength Ratio on the Stress-Strain Curve of Beta Titanium Alloy by Finite Element Modelling

A systematic study was undertaken to determine the effect of the β/α strength ratio on the stress-strain behavior of near beta titanium alloy by the finite element method where the volume percent of the second phase was constant at 16 vol.%. The β/α strength ratio of the harder β phase to the softer α phase was varied from approximately 4 to 5 where the a phase strength (0.2% YS) was kept constant at 296 MPa. It was found that the flow stress did not vary linearly with the strength ratio. Stress gradients were found in both α and β phases and the nature of the stress gradient was found to depend on α particle shape. In some locations higher stresses were found in near the interface. In β, the stresses were generally higher near the interfaces

A single molecule switch based on two Pd nanocrystals linked by a conjugated dithiol

Tunneling spectroscopy measurements have been carried out on a single molecule device formed by two Pd nanocrystals (dia, $\sim$5 nm) electronically coupled by a conducting molecule, dimercaptodiphenylacetylene. The I-V data, obtained by positioning the tip over a nanocrystal electrode, exhibit negative differential resistance (NDR) on a background M-I-M characteristics. The NDR feature occurs at $\sim$0.67 V at 300 K and shifts to a higher bias of 1.93 V at 90 K. When the tip is held in the middle region of the device, a coulomb blockade region is observed ($\pm\sim$0.3 V).Comment: Accepted in Praman

When and how to choose ferroalloys for cast iron foundry

Ferroalloys find extensive use in foundry for various specific purposes. The present paper discusses the use of ferroalloys in cast iron foundry as an, additive to moulding sand, as an inoculant for the production of graded cast irons, as an alloying element for the product-ion of alloy cast irons, also as an inoculant for the production of special cast irons such as S.G. iron, Mall-eable iron, compacted graphite cast irons. The paper also discusses the scope of production of complex inoculants as a present day need for foundry industry

The eigenspectra of Indian musical drums

In a family of drums used in the Indian subcontinent, the circular drum head is made of material of non-uniform density. Remarkably, and in contrast to a circular membrane of uniform density, the low eigenmodes of the non-uniform membrane are harmonic. In this work we model the drum head by a non-uniform membrane whose density varies smoothly between two prescribed values. Using a Fourier-Chebyshev spectral collocation method we obtain the eigenmodes and eigenvalues of the drum head. For a suitable choice of parameters, which we find by optimising a cost function, the eigenspectra obtained from our model are in excellent agreement with experimental values. Our model and the numerical method should find application in numerical sound synthesis

Studies on the extraction and characterization of thermostable a-amylase from pericarp of Borassus indica

Thermostable a-amylase was extracted and characterized from the fruits (pericarp) of Borassus indica. Analysis on the influence of various physico-chemical parameters on the extracted enzyme revealed a Vmax of 0.793 and a Km of 0.022. The optimum temperature was found to be 370C at pH 4.5. The stability studies on enzyme activity envisaged that the enzyme is stable up to 800C and retained its activity over a wide range of pH (4.0 – 8.5). Significant enhancement in the enzyme activity was observed in the presence of metal ions like Manganese and Strontium and an insignificant decrement in the presence of Sodium ions.African Journal of Biotechnology Vol. 4 (3), pp. 289-291, 200

White Lines and 3d-Occupancy for the 3d Transition-Metal Oxides

Electron energy-loss spectrometry was employed to measure the white lines at the L23 absorption edges of the 3d transition-metal oxides and lithium transition-metal oxides. The white-line ratio (L3/L2) was found to increase between d^0 and d^5 and decrease between d^5 and d^10, consistent with previous results for the transition metals and their oxides. The intensities of the white lines, normalized to the post-edge background, are linear for the 3d transition-metal oxides and lithium transition-metal oxides. An empirical correlation between normalized white-line intensity and 3d occupancy is established. It provides a method for measuring changes in the 3d-state occupancy. As an example, this empirical relationship is used to measure changes in the transition-metal valences of Li_{1-x}Ni_{0.8}Co_{0.2}O_2 in the range of 0 < x < 0.64. In these experiments the 3d occupancy of the nickel ion decreased upon lithium deintercalation, while the cobalt valence remained constant.Comment: 6 pages, 7 figure

Unsupervised decoding of long-term, naturalistic human neural recordings with automated video and audio annotations

Fully automated decoding of human activities and intentions from direct neural recordings is a tantalizing challenge in brain-computer interfacing. Most ongoing efforts have focused on training decoders on specific, stereotyped tasks in laboratory settings. Implementing brain-computer interfaces (BCIs) in natural settings requires adaptive strategies and scalable algorithms that require minimal supervision. Here we propose an unsupervised approach to decoding neural states from human brain recordings acquired in a naturalistic context. We demonstrate our approach on continuous long-term electrocorticographic (ECoG) data recorded over many days from the brain surface of subjects in a hospital room, with simultaneous audio and video recordings. We first discovered clusters in high-dimensional ECoG recordings and then annotated coherent clusters using speech and movement labels extracted automatically from audio and video recordings. To our knowledge, this represents the first time techniques from computer vision and speech processing have been used for natural ECoG decoding. Our results show that our unsupervised approach can discover distinct behaviors from ECoG data, including moving, speaking and resting. We verify the accuracy of our approach by comparing to manual annotations. Projecting the discovered cluster centers back onto the brain, this technique opens the door to automated functional brain mapping in natural settings