Thiruvananthapuram, India

The Indian Institute of Space Science and Technology is a government aided institute and deemed university for the study and research of space science, located at Valiamala, Thiruvananthapuram, Kerala. It is the first university in Asia to be solely dedicated to the study and research of Outer Space. It was inaugurated on 14 September 2007 by G. Madhavan Nair, the then Chairman of ISRO. IIST is sponsored by the Indian Space Research Organisation under the Department of Space, Government of India. A. P. J. Abdul Kalam, former President of India, is the Chancellor of IIST.IIST offers regular engineering undergraduate courses and graduate programs including master's and doctorate degrees. IIST is rated as one of the most prestigious engineering institutes in India admitting a little more than 150 students to its undergraduate courses every year. All undergraduate students are granted full scholarships during the entire four-year period. Complete boarding and lodging are offered to the students inside the campus at no cost, provided they meet prescribed academic standards. The students meeting these standards are then recruited as scientists and engineers in the Department of Space facilities and Indian Space Research Organization centres all over India. Wikipedia.

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Cyriac J.,Indian Institute of Technology Madras | Cyriac J.,Purdue University | Cyriac J.,Indian Institute of Space Science and Technology | Pradeep T.,Indian Institute of Technology Madras | And 3 more authors.
Chemical Reviews | Year: 2012

A study was conducted to demonstrate low-energy ionic collisions at molecular solids. The investigations were limited to molecular surfaces and associated chemical processes occurring during impact of a hyperthermal energy ion. The term 'molecular solid' comprised the wide range of molecular materials that were used in ion/surface collision experiments. The energy regime considered in the investigations lied in an intermediate range. Primary ion energies of several kiloelectronvolts used in a secondary ion mass spectrometry (SIMS) experiment was considered in the case of condensed molecular solids to allow correlation with the results of chemical sputtering (CS) or other low-energy sputtering (LES) experiments.

Amarnath M.,Indian Institute of Information Technology, Design and Manufacturing | Praveen Krishna I.R.,Indian Institute of Space Science and Technology
Measurement: Journal of the International Measurement Confederation | Year: 2014

Gear is a vital transmission element, finding numerous applications in small, medium and large machinery. Excessive loads, speeds and improper operating conditions may cause defects on their bearing surfaces, thereby triggering abnormal vibrations in whole machine structures. This paper describes the implementation of empirical mode decomposition (EMD) method for monitoring simulated faults using vibration and acoustic signals in a two stage helical gearbox. By using EMD method, a complicated signal can be decomposed into a number of intrinsic mode functions (IMF) based on the local characteristic time scale of the signal. Vibration and acoustic signals are decomposed to extract higher order statistical parameters. Results demonstrate the effectiveness of EMD based statistical parameters to diagnose severity of local faults on helical gear tooth. Kurtosis values from EMD and that obtained from vibration and acoustic signals are compared to demonstrate the superiority of EMD based technique. © 2014 Elsevier Ltd. All rights reserved.

Gupta N.,Indian Institute of Space Science and Technology | Gupta N.,Raman Research Institute
Astroparticle Physics | Year: 2012

The PeV gamma ray background produced in the interactions of ultra high energy cosmic rays with the ambient matter and radiations during their propagation in the Milky Way has been calculated in this paper. If the primary ultra high energy cosmic rays are produced from Galactic point sources then those point sources are also emitting PeV gamma rays. We discuss that the detection of galactocentric PeV gamma rays in the future would be a signature of the presence of EeV cosmic accelerators in the Milky Way. © 2011 Elsevier B.V. All rights reserved.

Ravi V.,Indian Institute of Space Science and Technology
Journal of Cleaner Production | Year: 2012

Primary constituents of e-waste from end-of-life (EOL) computers consist of glass, metals and plastics. Thus the quality of recycling of e-waste is dependent upon individual indicators like cathode ray tube (CRT) recycling, plastics recycling and recovery of metals which in turn is dependent upon various other attributes. The problem of assigning a single overall measure of quality to each system in a set of similar EOL computers recycling systems has not been duly addressed in literature. An aggregate measure of total quality of recycling system for EOL computers would be helpful to top management in accessing overall development where different versions of recycled products are produced. Thus, the central idea in this research is to combine different types of recycling process parameters into an aggregate value representing the overall quality of recycling of each of the systems. In this research, we have used Multi-Attribute Global Inference of Quality (MAGIQ) technique for accomplishing this objective. Results of research conducted in a case company show that application of this technique can provide decision makers with a clear picture on the quality of various recycling systems under evaluation. © 2011 Elsevier Ltd. All rights reserved.

Rajesh R.,Indian Institute of Space Science and Technology | Ravi V.,Indian Institute of Space Science and Technology
Journal of Cleaner Production | Year: 2015

Suppliers can be considered as inevitable sources of external risks in modern supply chains. In this context, resilience that stands for the adaptive capability to respond to disruptions and recovering from it needs to be considered in supplier selection. But selection of suppliers is a challenging issue that involves the evaluation of both qualitative and quantitative attributes, in usual have imprecise and limited information. Grey relational analysis based on linguistic assessment of supplier rating and attribute weightings could judiciously be used under these situations to obtain a set of possibility values for prioritizing supplier selection. In this research, a supplier to be selected in the context of a resilient supply chain is termed as a resilient supplier. Taking electronic supply chain as a case study, with six alternative suppliers, grey possibility values for supplier selection were calculated and the suppliers were prioritized. Sensitivity analysis was also conducted to identify how far the selection priorities of suppliers change by varying the weightings given to each of the resilience attributes. This helps us in identifying the attributes of resilience where a particular supplier performs well. A comparison of proposed grey methodology with analytic hierarchy process (AHP) and analytic network process (ANP) was also conducted to comprehend extent of out-performance. The results of the proposed research could help top management in taking strategic level decision making with respect to selection of suppliers in a resilient supply chain. © 2014 Elsevier Ltd.

Mukthar Ali M.,Indian Institute of Space Science and Technology | Sandhya K.Y.,Indian Institute of Space Science and Technology
Carbon | Year: 2014

Titanium dioxide (TiO2)-fullerene (C60) composite is prepared from TiO2 and β-cylcodextrin (CD) encapsulated C 60 using the solar light irradiation. The absorption of the composite extends to the visible light region due to the charge transfer from CD and C60 to TiO2. The composite shows reduced charge recombination compared to that of the bare TiO2 and TiO 2/CD. The rate constant values for the photodegradation reactions of methylene blue and 4-chlorophenol (4-CP) are significantly higher (∼2-5 times) for the composites with 0.5 and 1.5 wt.% C60 compared to that of the bare TiO2. Photocatalytic studies in the presence of scavengers reveal that the composites produce higher amount of reactive oxygen species (ROS). The enhanced photocatalytic activity of the composites is attributed to the visible light responsiveness, reduced charge recombination and increased formation of ROS. The photodegradation of 4-CP is significantly faster in the presence of the composite with 1.5 wt.% C60 and is attributed to the synergistic effect of higher adsorption and increased ROS formation. The ROS formation by C60 is possible because of the non-aggregated state of C60 molecules in the composite and is assigned to the method which employs CD molecules to disperse C60 in the composite. © 2013 Elsevier Ltd. All rights reserved.

Remyamol T.,Indian Institute of Space Science and Technology | John H.,Indian Institute of Space Science and Technology | Gopinath P.,Indian Institute of Space Science and Technology
Carbon | Year: 2013

Reduced graphene oxide covalently decorated with polyaniline was synthesized through a novel three step approach. Graphite oxide synthesized by a modified Hummers method, was first subjected to acylation, followed by a covalent functionalization with phenylene diamine and then it was polymerized along with aniline monomer, hence forming amide linkages between polyaniline and reduced graphene oxide. The covalent linkage formed was characterized by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Morphology was studied by scanning electron microscopy. The hybrid showed improved nonlinear optical properties compared to the graphene oxide precursor and the pristine polyaniline. The improvement in the optical limiting performance of the hybrid is attributed to a combination of outstanding properties of graphene oxide and polyaniline, like nonlinear scattering, two photon absorption and reverse saturable absorption. © 2013 Elsevier Ltd.

Narasimman R.,Indian Institute of Space Science and Technology | Prabhakaran K.,Indian Institute of Space Science and Technology
Carbon | Year: 2013

Boric acid was used as a blowing agent as well as a boron precursor for the preparation of boron-doped carbon foams from molten sucrose. The H+ generated, due to the formation of a complex between sucrose and boric acid, catalyzes the -OH to -OH condensation reaction leading to the polymerization and the foaming of the molten sucrose. The char yield of the solid organic foams increased from 24 to 39 wt.% when the boric acid concentration increased from 0 to 8 wt.%, due to the formation of the B-O-C cross-links between sucrose polymer by B-OH to C-OH condensation. The inductively coupled plasma analysis showed the presence of 0.44-3.4 wt.% boron in the carbon foams. The density and compressive strength decreased and cell size increased with boric acid concentration. The room temperature thermal conductivity of the boron-doped carbon foams was in the range of 0.057-0.043 W m-1 K-1. The weight loss studies by dynamic and isothermal heating showed the increased oxidation resistance with boron concentration. © 2012 Elsevier Ltd. All rights reserved.

Narasimman R.,Indian Institute of Space Science and Technology | Prabhakaran K.,Indian Institute of Space Science and Technology
Carbon | Year: 2012

Thermo-foaming of activated carbon (AC) powder dispersions in an aqueous sucrose resin followed by carbonization has been studied to prepare carbon foams. The dispersions were characterized by viscosity measurements and sedimentation studies. The OH to OH condensation reactions, leading to the cross-linking of the sucrose polymer, were retarded by the AC powder. The AC particles adsorbed on the gas-liquid interface stabilized the gas bubbles that resulted in foaming of the poorly cross-linked sucrose polymer resin having low viscosity. The carbon produced by the carbonization of the sucrose polymer binds the AC particles as in reaction bonding. The carbon foams have an interconnected cellular structure. Density (0.138-0.22 g/cc), cell size (0.62-3 mm) and compressive strength (0.42-3.4 MPa) of the carbon foams depends on the AC powder to sucrose weight ratio. Incorporation of the AC powder in the sucrose resin decreases the carbonization shrinkage that enables the preparation of large carbon foam bodies without warping. The carbon foam prepared at an AC powder to sucrose weight ratio of 0.1 shows the highest density and compressive strength and the lowest cell size. © 2012 Elsevier Ltd. All rights reserved.

Narasimman R.,Indian Institute of Space Science and Technology | Prabhakaran K.,Indian Institute of Space Science and Technology
Carbon | Year: 2012

Low density carbon foams have been prepared by thermo-foaming of molten sucrose using aluminium nitrate as a blowing agent to produce solid organic foams followed by dehydration and carbonization. Gas bubbles are generated in the molten sucrose due to water vapour produced by the acid catalysed condensation between sucrose hydroxyl groups and NO x gases produced by the thermal decomposition of the aluminium nitrate. Higher melt viscosity achieved by cross-linking of the condensation products of sucrose through co-ordination of the aluminium ions with the hydroxyl groups stabilizes the bubbles against coalescence and rupture. The foam volume, foaming time and setting time depend on the aluminium nitrate concentrations. The carbon obtained by the pyrolysis of the solid organic foams has turbostratic graphite structure. The foams produced have an interconnected near-spherical cellular structure. The carbon foams prepared at aluminium nitrate concentrations in the range of 0.5-4 wt.% have a density and average cell size in the ranges of 0.085-0.053 g/cc and 1.55-0.83 mm, respectively. The alumina (∼0.17-1.34 wt.%) produced from the aluminium nitrate is concentrated more on the surface of cell walls, ligaments, and struts. © 2012 Elsevier Ltd. All rights reserved.

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