Technical note Temporal remote sensing data and GIS application in landslide hazard zonation of part of Western ghat,India

Spatial and temporal multi-layered information is required to assess landslide hazard susceptibility. The manual method of data integration for targeting potential zones susceptible to landslide hazard is time consuming. The present study highlights the utility of temporal remotely-sensed data and knowledgebased Geographical Information Systems for collection, integration and analysis of spatially-oriented data, as well as in finding out the inherent relation between separate entities in parts of West ghat in India.     

Adaptive Discretization for Computerized Tomography

Two adaptive discretization frameworks are tested for computerized tomography (CT) data reconstruction. Removal of inactive pixels is primary motivation. Efficient and user independent entropy optimized masking is employed for spatial filtering purposes. Density of nodes at high gradient of reconstructed physical property is used as adaptation criterion. An alternative option, independent from noisy projection data and nature of the physical properties, is also discussed. Sensitivity analysis between the uniform and nonuniform (evolved via adaptive route) reconstruction grid reveals the utility of nonuniform grids. Iterative and transform based reconstruction techniques are used. Outcomes are tested successfully on three real world projection data from two different compact CT setups and one commercial high-resolution micro-CT scanner.     

Rebar corrosion in chloride environment

Chloride induced reinforcement corrosion in concrete is a serious durability problem. Different sources of chloride, i.e. chloride introduced at the fresh stage of concrete (i.e. internal chloride) and chloride entered during the hardened state (i.e. external chloride) may affect the performance of concrete in different ways. For the performance evaluation of reinforced concrete in chloride environment (i.e. both internal and external chloride), there is a need for performing different electrochemical tests to obtain various corrosion parameters that will specify the possibility and the magnitude of corrosion in concrete. In the present study, the results of an experimental investigation that includes different corrosion tests namely potential measurement, corrosion rate measurement and potentiodynamic polarization test have been presented and analyzed to evaluate the performance of concrete both in internal chloride and external chloride exposure conditions. In addition an attempt is made to correlate the corrosion parameters obtained from internal and external chloride exposure conditions. From the results it was observed that, dropped half-cell potential value obtained from external chloride exposure mostly lie in the active zone obtained from internal chloride exposure. In addition it was observed that there was significant difference in corrosion current values obtained from both internal and external chloride exposure conditions. Further on the basis of overall ranking obtained from the results of critical parameters from different exposure conditions, the performance of different cement–steel combinations against chloride induced rebar corrosion has been evaluated.     

Thermodynamic mechanism of free heme action on sickle cell hemoglobin polymerization

For insights into the mechanisms of heme action on the rate of sickle cell hemoglobin polymerization, we determine the erythrocytic concentration of free heme using a novel method based on enzymatic catalysis and luminescence. We find in sickle cell patients 44 ± 10 µM, in sickle trait individuals, 33 ± 4 µM, and in healthy adults, 21 ± 2 µM. We test the applicability of two mechanisms of heme action: a kinetic one, whereby heme aggregates serve as heterogeneous nucleation centers, and a thermodynamic pathway, in which free heme enhances the attraction between sickle hemoglobin (HbS) molecules in solution. We show that the latter mechanism exclusively operates. The enhanced attraction leads to increase of the total volume of a population of dense liquid clusters by about two orders of magnitude. As the dense liquid clusters serve as locations and precursors to the formation of the HbS polymer nuclei, their increased volume directly leads to faster polymer nucleation. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2861–2870, 2015     

Experimental and simulation study of magnetorheological miniature gear-profile polishing (MRMGPP) method using flow restrictor

Journal of Mechanical Science and Technology - In this article, a new flow restrictor is utilized in the magnetorheological miniature gear-profile polishing (MRMGPP) method to ensure a consistent...     

Fragmentation and granular transition of ceramics for high rate loading

The paper presents a numerical model to study the transition of brittle materials from a cracked solid to a granular medium under impact loading. The model addresses competitive crack coalescence in the transition regime and provides insight into the onset of comminution and the initial conditions for subsequent granular flow. Crack statistics obtained from initial flaws using a wing crack growth-based damage model have been used to discretely model elliptical cracks in three dimensions. These discrete cracks are either generated randomly in space or with a constraint that minimizes the intersection between neighboring cracks. These cracks are then allowed to coalesce with nearby cracks along with favorable directions and the output fragment statistics are predicted. A simple statistical model is proposed that suggests a transition criterion resembling the one obtained from the numerical model. Initial fragments are power-law distributed similarly to experimental observations and particle-based models. A generalized form of a microstructure-dependent granular transition criterion based on a threshold measure of crack lengths has been proposed. This model can be implemented in numerical codes to activate granular physics and calibrate the initial conditions of granular flow, such as fragment size and morphology.     

Phase Transformations in Third Generation Gamma Titanium Aluminides: Ti-45Al-(5, 10) Nb-0.2B-0.2C

Third generation γ-titanium aluminides with nominal compositions Ti–45Al–5Nb–0.2B–0.2C and Ti–45Al–10Nb–0.2B–0.2C were investigated to identify the phase transformation and their morphological stability with temperature. Electron microscopy and differential scanning calorimetry were employed for the characterization of phases and for recording the corresponding transformations, respectively. It has been inferred that the order–disorder transformation temperatures α₂ → α increased with increasing Niobium (Nb), while the α-transus temperature decreases. The stability of the microstructure for both alloys with temperature were also investigated. Mass change measured for the heating rates 20 °C s⁻¹ and 30 °C s⁻¹ reveals that the alloy Ti–45Al–10Nb–0.2–0.2C shows stability up to 1100 °C, and the alloy Ti–45Al–5Nb–0.2B–0.2C is stable up to 900 °C. The orientation relationship between the phases indicates that with the change in shape of the α phase from lamellar to equiaxed, it deviates from the Blackburn orientation relationship.

     

Identifying Erosion Mechanism: A Novel Approach

Understanding the erosion mechanism is a key to improve the performance of material subjected to erosive condition. Capability to predict the erosion mechanism could prove to be useful tool. In this work, a parameter named “erosion mechanism identifier,” ξ, is proposed to predict the erosion mechanism in materials. Suitability of ξ in predicting erosion mechanism of ductile and brittle materials was evaluated using the data reported in the literature. It was observed that ξ is able to predict the erosion mechanism for both categories of material. The predictability of ξ was not restrained by different operating conditions.     

Removal of lead from contaminated water bodies using sea nodule as an adsorbent

Adsorption of water soluble lead on polymetallic sea nodule has been studied in detail. Complete decontamination of lead is possible by appropriate sea nodule dosing. Adsorption is also dependent on pH and best adsorption is achieved at pH 6. Beyond pH 6, the desorption of lead from sea nodule surface is practically zero. Residual metal concentrations in the filtrate after adsorption is negligible. Both Freundlich and Langmuir isotherms may reasonably explain adsorption of lead on sea nodule. Chemically bound moisture plays a very crucial role in lead adsorption. Lead adsorptive capability of sea nodule is practically destroyed when calcined at a temperature of 900 degrees C. Lead loading capacity of sea nodule has been estimated at 440 mg of lead per gram of sea nodule. The performance of sea nodule as a lead adsorbent has been successfully tested over six simulated lead contaminated water systems. Lead loading capacity of sea nodule compares favorably with other adsorbents like activated carbon, ion exchange resin, anionic clay, granulated blast furnace slag and natural and treated zeolites.     

Olfactometric characterization of aroma active compounds in fermented fish paste in comparison with fish sauce,fermented soy paste and sauce products

Aroma active compounds in commercial fermented fish meat paste product (fish miso), fermented soy paste (soy miso), fish sauce and soy sauces were characterized by using a dynamic headspace method for volatile isolation and GC olfactometry for odor perception. A total of 123 volatile compounds consisting mainly of aldehydes, alcohols, esters, ketones, furans, sulfur and nitrogen-containing compounds, aromatics and acids were consistently identified. A major 16 odor-active compounds were distinguished to contribute as key aroma compounds for the miso and sauce products. Olfactometric and sensory findings clearly differentiated miso products with caramelic, fruity aroma notes, whereas fish sauce products were characterized by ammoniacal, fishy, nutty and cheesy odor note. Soy sauce products, however, were dominated by nutty and cheese aroma. Use of koji for fish miso production was found effective to enhance sweet aroma to the product with a reduction of nutty, meaty and rancid nuance. Principal component analysis employed for statistical interpretations clearly elucidated the relationship among different types of fermented products.