Temporal radiance caching

Curved planar reformation (CPR) has proven to be a practical and widely used tool for the visualization of curved tubular structures within the human body. It has been useful in medical procedures involving the examination of blood vessels and the spine. However, it is more difficult to use it for large tubular structures such as the trachea and the colon because abnormalities may be smaller relative to the size of the structure and may not have such distinct density and shape characteristics. Our new approach improves on this situation by using volume rendering for hollow regions and standard CPR for the surrounding tissue. This effectively combines gray-scale contextual information with detailed color information from the area of interest. The approach is successfully used with each of the standard CPR types, and the resulting images are promising as an alternative to virtual endoscopy. Because CPR and volume rendering are tightly coupled, the projection method used has a significant effect on the properties of the volume renderer, such as distortion and isometry. We describe and compare the different CPR projection methods and how they affect the volume rendering process. A version of the algorithm is also presented which makes use of importance-driven techniques; this ensures the users' attention is always focused on the area of interest and also improves the speed of the algorithm.     

Rendering Trees with Indirect Lighting in Real Time

High quality lighting is one of the challenges for interactive tree rendering. To this end, this paper presents a lighting model allowing real‐time rendering of trees with convincing indirect lighting. Rather than defining an empirical model to mimic lighting of real trees, we work at a lower level by modeling the spatial distribution of leaves and by assigning them probabilistic properties. We focus mainly on precise low‐frequency lighting that our eyes are more sensitive to and we add high‐frequency details afterwards. The resulting model is efficient and simple to implement on a GPU.     

Subsurface texture mapping.

This article presents a rendering technique for multilayered materials. Unlike existing methods, our technique does not assume that the thickness of these layers is constant. We use relief texture mapping to model a material's interior. Instead of representing the surface details, we use this method to represent the object's inner structure. We describe the material's layers using a simple 2D texture, in which each channel encodes a thickness. Our method supports nonplanar surfaces and falls between subsurface rendering methods based on surfaces and 3D texture-based algorithms. Furthermore, our solution provides a compact way to design translucent objects using a small amount of data.     

Characterisation of low-grade Barsua iron ore fines and identification of possible beneficiation strategies

The consumption of iron ore has increased rapidly over the past decade due to the tremendous growth of the iron and steel industry. The depletion of high-grade iron ore resources makes it inevitable to utilise the existing low-grade iron ores/fines/tailings with proper beneficiation to meet the present specification and demand. Beneficiation and utilisation of these fines/tailings still remains a challenging task. In order to find out an effective way of utilisation of these fines, an in-depth characterisation study is essential. A detailed insight into the different mineralogical attributes involving microscopic (both optical and electron), X-ray diffraction, Fourier Transform Infrared Spectroscopy, Thermo Gravimetric Analysis, physical and chemical characterisation, are undertaken on the Barsua iron ore fines. These studies revealed that haematite and goethite are the major iron-bearing minerals with gibbsite, kaolinite and quartz present as gangue. Traces of magnetite are also observed. The liberation size of the sample is found to be below 150?µm. The bulk chemical composition shows around 57.67% Fe, 6.29% Al₂O₃, 3.52% SiO₂ and 6.93% LOI. Based on the detailed characterisation, a possible route of beneficiation of these iron ore fines is discussed and successful implementation of the beneficiation strategies is envisaged.     

Mycobacterium tuberculosis Acetyltransferase Suppresses Oxidative Stress by Inducing Peroxisome Formation in Macrophages

Mycobacterium tuberculosis (Mtb) inhibits host oxidative stress responses facilitating its survival in macrophages; however, the underlying molecular mechanisms are poorly understood. Here, we identified a Mtb acetyltransferase (Rv3034c) as a novel counter actor of macrophage oxidative stress responses by inducing peroxisome formation. An inducible Rv3034c deletion mutant of Mtb failed to induce peroxisome biogenesis, expression of the peroxisomal β-oxidation pathway intermediates (ACOX1, ACAA1, MFP2) in macrophages, resulting in reduced intracellular survival compared to the parental strain. This reduced virulence phenotype was rescued by repletion of Rv3034c. Peroxisome induction depended on the interaction between Rv3034c and the macrophage mannose receptor (MR). Interaction between Rv3034c and MR induced expression of the peroxisomal biogenesis proteins PEX5p, PEX13p, PEX14p, PEX11β, PEX19p, the peroxisomal membrane lipid transporter ABCD3, and catalase. Expression of PEX14p and ABCD3 was also enhanced in lungs from Mtb aerosol-infected mice. This is the first report that peroxisome-mediated control of ROS balance is essential for innate immune responses to Mtb but can be counteracted by the mycobacterial acetyltransferase Rv3034c. Thus, peroxisomes represent interesting targets for host-directed therapeutics to tuberculosis.     

Multidimensional illumination functions for visualization of complex 3D environments

This paper presents a new view-independent, energy equilibrium method for determining the light distributed in a complex 3D environment consisting of surfaces with general reflectance properties. The method does not depend on discretization of directions or discretization of surfaces to differential elements. Hence, it is a significant improvement over the earlier complete view-independent method which is computationally intractable for complex environments or the hybrid methods which include an extended view-dependent ray tracing second pass. The new method is based on an efficient data structure of order O(N²) called the spherical cover. The spherical cover elegantly captures the complex multidimensional directional nature of light distributed over surfaces. Subdivision techniques based on range estimation of various parameters using interval-arithmetic-like methods are next described for efficiently computing the spherical cover for a given 3D environment. Using the spherical cover, light is progressively propagated through the environment until energy equilibrium is reached. Complexity analysis of the propagation step is carried out to show that the method is computationally tractable. The paper also includes a comprehensive review of earlier rendering techniques viewed from the point of view of capturing the multidimensional nature of light distribution over surfaces.     

Virtual grid-based rendezvous point and sojourn location selection for energy and delay efficient data acquisition in wireless sensor networks with mobile sink

Wireless Networks - Rendezvous points (RPs) based data acquisition methods are widely accepted as the solution for data acquisition delay/latency problem. In these methods, RPs are a subset of...     

Kinetics and Grain Boundary Selectivity of Discontinuous Precipitation in Binary Ni-Cr Alloy

A supersaturated Ni-Cr alloy (42 wt pct Cr) was subjected to a series of aging heat treatments in the two-phase region in the temperature range of 923 K to 1123 K (650 °C to 850 °C) for different time periods. The resultant microstructures were seen to be composed of varying volume fractions of continuous (CP) and discontinuous precipitation (DP). The DP dominated at lower temperatures, while CP dominated at higher temperatures and the expected DP termination temperature was estimated to be 1138 K (865 °C). The kinetics of DP followed the Turnbull model at lower temperatures and the Aaronson–Liu model at higher temperatures. The nucleation and growth of DP cells, which occurred via the ‘precipitate driven grain boundary migration,’ was seen to be a strong function of the nature of the participating grain boundaries.

     

Selection of a Viable Upgradation Strategy Through Physico-chemical and Mineralogical Approach: A Case Study of Low Grade Barsua Iron Ore Fines

Detailed characterization study is the pioneer step for any mineral beneficiation scheme. A series of mineralogical and peterographic studies coupled with (Brunauer–Emmett–Teller) surface area, (atomic force microscopy), (laser diffraction particle size analyser), FTIR (Fourier transform infrared spectroscopy), contact angle measurement, zeta potential were carried out, and the findings about the mineralogical and physico-chemical nature of the sample have been described. This paper provides a guide on the proper selection of beneficiation route for iron ore with complex mineral assemblage (Hematite–Goethite–Laterite–Quartz–Kaolinite–Gibbsite). The beneficiation method, especially froth flotation process, potential after a thorough characterization is suggested analysed and the successful upgradation by froth flotation route is envisaged. Flotation results indicated that it is possible to achieve high grade iron concentrate along with lower silica, and alumina content providing a specific reagent regime/system for specific mineral assemblages.     

PVT variations aware low leakage INDEP approach for nanoscale CMOS circuits

Increasing in device parameter variations is the critical issue in very deep sub-micron regime due to continue scaling of the transistor dimensions. The overall performance yield of the logic circuit is diminished by raising leakage current and variability issues in scaled devices. In this article; we have proposed an approach called INDEP, based on Boolean logic calculation for the input signals of the extra inserted transistors between the pull-up and pull-down network of the CMOS logic. INDEP approach is not only reduces the leakage current but also mitigates the variability issues with minimum susceptible delay paths. Various process, voltage and temperature (PVT) variations are analyzed at 22 nm BSIM4 bulk CMOS PTM technology node for chain of 5-inverters using HSPICE tool. Several guidelines are provided to design the variability aware CMOS circuits in nanoscale regime by considering the leakage current variation. INDEP approach works effectively in both active as well as standby state of the circuit and keeping the modal performance characteristics of the CMOS gate. The electrical simulation results show that our proposed INDEP approach is less susceptible to PVT variations as compared to conventional circuit. The Monte-Carlo simulation results confirm that average INDEP leakage current reduction is 62.31% at ±20% PVT variations under 3σ Gaussian distribution for chain of 5-inverters.